JPH0321785B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides hydraulic control for controlling a continuously variable automatic transmission for vehicles using a V-belt type continuously variable transmission according to vehicle running conditions such as vehicle speed and throttle opening. The present invention relates to a reduction ratio control device that is provided in a control device and controls the V-belt type continuously variable transmission.

[Prior Art] Conventionally, a reduction ratio control device in a continuously variable automatic transmission for a vehicle includes a valve that controls the supply and discharge of hydraulic fluid to a hydraulic servo, and a first valve that biases this valve in the upshift direction. It consists of an oil chamber, a second oil chamber for biasing in the downshift direction, and an electromagnetic solenoid valve that controls the supply of hydraulic pressure to each oil chamber. Alternatively, this is achieved by displacing the downshifting electromagnetic solenoid valve by opening and closing the valve.

[Problems to be Solved by the Invention] However, when starting or suddenly downshifting, the operating oil is discharged from the first oil chamber by opening the downshifting electromagnetic solenoid valve, and the upshifting electromagnetic solenoid valve is opened. By supplying hydraulic oil to the second oil chamber by the closing operation of
The valve is displaced to the downshift side, and when the valve is operated on the downshift side, hydraulic oil from the oil pump is constantly discharged through the downshift electromagnetic solenoid valve. Therefore, there is a problem in that oil pump loss increases.

In addition, since the downshift solenoid valve must be kept open at all times when the valve is activated, the downshift solenoid valve must be constantly energized, which reduces the durability of the downshift solenoid valve. be.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the oil pump loss when the reduction ratio control means is set to the downshift side, and to reduce the loss of the electromagnetic solenoid. An object of the present invention is to provide a reduction ratio control device for a continuously variable automatic transmission for a vehicle, which can improve the durability of the device.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention comprises an input pulley, an output pulley, and an endless belt stretched between these input and output pulleys, In a continuously variable automatic transmission for vehicles, which performs continuously variable speed by changing the effective diameter at the frictional engagement position between each pulley and an endless belt using a hydraulic servo, Reduction ratio control means controlled by control hydraulic pressure to control the supply and discharge of hydraulic pressure to the hydraulic servo; and upshift electromagnetic solenoid means for controlling the control hydraulic pressure so as to set the reduction ratio control means to the upshift side. a downshift electromagnetic solenoid means for controlling the control oil pressure so as to set the reduction ratio control means to the downshift side; and an operation of the downshift electromagnetic solenoid means to control the control oil pressure to shift the reduction ratio control means. The present invention is characterized in that a holding means is provided for holding the reduction ratio control means on the downshift side by cutting off control hydraulic pressure from the hydraulic oil from the oil pump when the gear ratio control means is set on the downshift side.

[Function and Effects of the Invention] According to the reduction ratio control device for a continuously variable automatic transmission for a vehicle of the present invention configured as described above, the reduction ratio control device is controlled by the control oil pressure using the hydraulic oil from the oil pump,
reduction ratio control means for controlling the supply and discharge of hydraulic pressure to the hydraulic servo; upshift electromagnetic solenoid means for controlling the control hydraulic pressure so as to set the reduction ratio control means to the upshift side; a downshift electromagnetic solenoid means for controlling the control hydraulic pressure so as to set it to the shift side; and when the control hydraulic pressure is controlled by the operation of the downshift electromagnetic solenoid means and the reduction ratio control means is set to the downshift side. and a holding means for holding the reduction ratio control means on the downshift side by cutting off the control hydraulic pressure from the hydraulic oil from the oil pump, so that when the reduction ratio control means is set on the downshift side, Even if the power supply to the downshift electromagnetic solenoid means is stopped and the electromagnetic solenoid means is deactivated, the control hydraulic pressure by the hydraulic oil from the pump is cut off by the holding means, and the reduction ratio control means is held on the downshift side. Ru.
Therefore, the hydraulic oil from the pump is not discharged unnecessarily, and oil pump loss is reduced. Furthermore, while the reduction ratio control means is being set to the downshift side, the downshift electromagnetic solenoid means does not need to be energized all the time, so the durability of the electromagnetic solenoid means is improved.

[Example] Hereinafter, an example of the present invention will be described using the drawings.

FIG. 1 is a sectional view showing an example of a continuously variable automatic transmission for a vehicle to which an embodiment of the reduction ratio control mechanism for a continuously variable automatic transmission for a vehicle according to the present invention is applied.

As shown in FIG. 1, a continuously variable automatic transmission for a vehicle includes a hydraulic torque converter 100 with a direct coupling clutch,
It includes a planetary gear transmission mechanism 120 for forward/reverse switching, a V-belt continuously variable transmission 140, and a differential gear 170.

The torque converter 100 includes a front cover 101 connected to the output shaft of the engine, a pump impeller shell 102 welded to the front cover 101 and having an impeller attached to its inner periphery, and a torque converter in the center via a turbine hub 104. Turbine runner 1 connected to output shaft 103
05, consists of a stator 107 fixed to an inner case 110 via a one-way clutch 106, and a direct coupling clutch 108 that directly couples the turbine hub 104 and the front cover 101, and between the torque converter 100 and the planetary gear transmission mechanism 120. There is an oil pump 20 driven by the output of the engine.
is provided.

The forward/reverse switching planetary gear transmission 120 connects the output shaft 103 of the torque converter to the input shaft 10.
3, and the input shaft 141 of the V-belt type continuously variable transmission 140 connected in series with the output shaft is connected to the output shaft 141.
and a multi-disc clutch C1, a hydraulic servo 121 for operating the multi-disc clutch C1, and a multi-disc brake B.
1. Consists of a hydraulic servo 122 and a planetary gear set 130 for operating the multi-disc brake B1.
The planetary gear set 130 is connected to the input shaft 10.
3, annular hydraulic cylinder 123 of hydraulic servo 121
A sun gear 132 is connected to the hydraulic cylinder 123 via a multi-disc clutch C1 and is spline-fitted to the output shaft 141, and a transmission case via the multi-disc brake B1. A ring gear 133 and the carrier 131 that can be fixed to 220
The double planetary gear 134 is rotatably supported by the sun gear 132 and the ring gear 133, respectively.

The V-belt type continuously variable transmission 140 has the input shaft 1
41 and an output shaft 142 arranged parallel to the input shaft 141 are each driven by a hydraulic servo. Input pulley 150 and output pulley 16
0, and these input pulley 150 and output pulley 160 are connected by a V-belt 145 made of a steel band 143 made of overlapping ring-shaped thin plates and a large number of metal blocks 144 attached to it. The input pulley 150 includes a fixed flange 151 formed integrally with the input shaft 141 and a double piston 15.
a movable flange 155 driven by a hydraulic servo 154 of the input pulley having 2 and 153 to be axially displaced to increase or decrease the effective diameter of the input pulley;
Equipped with. The output pulley 160 is connected to the output shaft 1
A fixed flange 161 integrally formed with 42;
A movable flange 165 is provided which is driven by a hydraulic servo 164 of the output pulley having double pistons 162 and 163 to be displaced in the axial direction to increase or decrease the effective diameter of the output pulley.

The differential gear 170 includes a large drive gear 171 as an input gear, a gear box 172, a small differential gear 173, a large differential gear 174, and an output shaft 175 connected to an axle.

A governor valve 25 is provided at one end of the output shaft of the V-belt type continuously variable transmission, and an output gear 188 is rotatably supported at the other end, and a reduction planetary gear set 180 is provided at the other end. The planetary gear set 180 for deceleration includes a sun gear 181 connected to the output shaft 142, a ring gear 182 fixed to the transmission case 220, a carrier 183 connected to the output gear 188, and sun gear 181 and ring gear 182, respectively. It consists of a double planetary gear 184 which meshes with each other and is rotatably supported by a carrier 183.
The output gear 188 is connected to the driving large gear 171 of the differential gear by a chain 190.

FIG. 2 shows a control device for controlling the speed change of the continuously variable automatic transmission for a vehicle shown in FIG. 1 shows a hydraulic control device in a control device for a continuously variable automatic transmission for a vehicle, which includes a hydraulic control device controlled by the device.

The hydraulic control device of this embodiment includes the oil pump 20 which is a hydraulic source and is driven by an engine, the governor valve 25 which outputs a governor pressure corresponding to the vehicle speed or the output shaft rotation speed of the V-belt continuously variable transmission;
A primary regulator valve 30 that supplies primary line pressure to the hydraulic control device, a secondary regulator valve 35 that supplies secondary line pressure to the hydraulic control device, a throttle valve 40 that outputs throttle pressure according to the throttle opening, and a governor. Outputs cutback pressure corresponding to the valve pressure to the throttle valve,
A cutback valve 45 that relates throttle pressure to vehicle speed (governor pressure), a line pressure adjustment valve 47 that outputs throttle control pressure regulated in relation to governor pressure to the primary regulator valve, input according to vehicle running conditions A reduction ratio control mechanism 50 that controls the supply and discharge of hydraulic oil to the hydraulic servo of the pulley and increases/decreases the reduction ratio of the V-belt continuously variable transmission, and is supplied to the hydraulic servo of the output pulley of the V-belt continuously variable transmission. A shift sequence mechanism 60 that changes the type of hydraulic pressure from primary line pressure to secondary line pressure in response to the operation of the reduction ratio control mechanism 50, balances the hydraulic pressure of the hydraulic servo during steady running of the input pulley, and balances the hydraulic pressure of the hydraulic servo. Input pulley modulator mechanism 66 to compensate for leakage, planetary gear transmission mechanism 1 operated by a shift lever provided to the driver
20, a manual valve 70 for switching between forward and reverse movement;
A shift control mechanism 75 and a torque converter 100 for smoothly engaging a multi-disc clutch or a multi-disc brake during N→D shifts and N→R shifts, and for inertial running in the D range.
The lockup control mechanism 80 operates the direct coupling clutch 108.

In the oil pump 20, a slide casing 204, which has a spring 202 on one side and a hydraulic servo 203 on the other side, is housed in a body 201 so as to be slidable about a fulcrum 205. 20
This is a variable displacement vane pump equipped with a rotor 207 with a 6-piece rotor 207, and sucks oil from an oil reservoir 208 through an oil strainer 209 and discharges it into the oil passage 1.

The governor valve 25 has a known configuration and is attached to the output shaft of the V-belt continuously variable transmission, and controls the line pressure supplied from the oil passage 1 to the output of the V-belt continuously variable transmission corresponding to the vehicle speed. The pressure is regulated according to the shaft rotation speed, and is output to the oil passage 6 as governor pressure, as shown in FIG.

The primary regulator valve 30 includes a spool 3 having a spring 31 on its back on one side (lower side in the figure).
2, and a regulator plunger 33 which is provided in series in the lower part of the figure in contact with the spool 32 so as to press the spool 32 from the same direction as the spring 31. The regulator plunger 33 is provided with an upper land 331 of a large diameter and a lower land 332 of a small diameter.
Throttle modulator pressure output from the line pressure regulating valve 48 supplied from the oil passage 7B via the orifice 341 or governor pressure supplied from the oil passage 6A connected to the oil passage 6 via the orifice 341 is applied. Throttle pressure is applied to the lower land 332 via the oil passage 7, and the spool 32 is pushed upward in the drawing by a pressing force corresponding to the input oil pressure. The spool 32 is displaced by the feedback of the primary line pressure applied from above in the figure through the orifice 301 to the top end land in the figure, and the spring load of the spring 31 and the pressing force of the regulator plunger 33 received from below in the figure. The communication area between the oil passage 1 and the oil passage 2 is increased or decreased to allow excess oil to flow out into the oil passage 2, and excess oil exceeding the outflow capacity from the oil passage 2 is drained from the drain port 302. As a result, the oil pressure in the oil passage 1 generates a primary line pressure P1 shown in FIG. 4, which is related to vehicle speed (governor pressure) and throttle opening (throttle pressure), which are the driving conditions of the vehicle.

The secondary regulator valve 35 includes a spool 3 having a spring 36 on its back on one side (lower side in the figure).
7 and a plunger 38 provided in series in the lower part of the drawing in contact with the spool 37, the first port 371 outputs the secondary line pressure, and the torque converter converts surplus oil when regulating the secondary line pressure. 100 and a second port 372 that supplies lubricating oil to the necessary parts of the automatic transmission, a third port 373 that outputs hydraulic pressure to control the amount of oil discharged to the variable displacement oil pump 20, and a drain port 35.
2,353, an input port 354 for throttle pressure, which is input oil pressure according to vehicle operating conditions, and an input port 355 for secondary line pressure.

The oil passage 5 communicating with the second port 372 is connected to an orifice 371 having a relatively large diameter.
It communicates with the oil passage 5A that supplies hydraulic oil to the torque converter 100 via the lock-up control valve 81 of the torque converter, and also communicates with the oil passage 5A that supplies hydraulic oil to the torque converter 100 through the lock-up control valve 81 of the torque converter. Oil passage 5B that supplies lubricating oil to parts that require lubrication
is in contact with.

The oil passage 2 where the secondary line pressure is generated and the oil passage 5A communicating with the lockup control valve 81 are connected via a small diameter orifice 393.
In addition, the oil passage 2 and the oil passage 5B for supplying lubricating oil are:
Further communication is provided via a small diameter orifice 394.

This secondary regulator valve 35 operates as follows.

In this secondary regulator valve 35, the spool 37 receives the feedback of the secondary line pressure of the oil passage 2 applied from the upper side in the figure via the orifice 351 to the upper end land in the figure, and receives the spring load from the spring 36 from the lower side in the figure. and oil road 7
It is displaced in response to the throttle pressure applied to the plunger 38 from above, and increases or decreases the communication area between the first port 371 communicating with the oil passage 2 and the second port 372 communicating with the supply oil passage 5 for lubricating oil, etc. When the primary line pressure is regulated by the primary regulator valve 30, the oil pressure in the oil passage 2, which is the oil passage through which excess oil spills, is regulated in accordance with the input oil pressure, which is the throttle pressure, and the secondary line shown in FIG. Outputs pressure P,
and a third port 373 communicating with the oil passage 8 that outputs control oil pressure to the oil pump hydraulic servo 203.
The communication area between the first port 371 and the drain port 352, which communicate with the oil passage 2, is adjusted to output hydraulic pressure to the hydraulic servo 203, thereby controlling the discharge capacity of the oil pump 20.

FIG. 6 shows the displacement of the spool 37 and the characteristics of oil pressure changes in the oil passages 5A, 5B, and 8 when the throttle pressure is constant.

When the secondary line pressure is within the set appropriate range (zone A in Figure 6).

The first port 371 and the second port 372 communicate with each other, and hydraulic pressure is generated in the oil passage 5, and the torque converter supply pressure in the oil passage 5A and the lubricating oil pressure in the oil passage 5B are mainly applied to the orifices 391 and 392, respectively. Hydraulic pressure is sufficiently supplied through the valve and is at an appropriate value.

The engine is running at low rpm and the oil pump 2
0, the amount of oil discharged from the primary regulator valve 30 is small, and as a result, the excess oil discharged from the primary regulator valve 30 to the oil path 2 is small, and the oil temperature is high, so oil leaks from various parts of the hydraulic circuit. When the pressure falls below the set appropriate range (zone B in Figure 6).

The spool 37 is displaced upward in the drawing to close the second port 372, stopping the discharge of excess oil from the oil passage 5 and maintaining the secondary line pressure. At this time, if no pressure oil is supplied to the oil passage 5A, the direct coupling clutch 10 in the torque converter 100
8 cannot be reliably maintained in the released state, resulting in wear due to the drag of the direct coupling clutch, and insufficient circulation of the hydraulic oil to the oil cooler, which tends to cause excessive temperature rise of the hydraulic oil in the torque converter. In the present invention, the minimum necessary hydraulic oil is supplied from the oil passage 2 through the small diameter orifice 393 into the oil passage 5A, and from the oil passage 5A is supplied to the torque converter 100 via the direct coupling clutch control valve 81. Prevents clutch drag and excessive temperature rise of hydraulic oil. Also, oil path 5B
If no lubricating oil is supplied to the sliding parts that require lubrication, seizure is likely to occur, so the minimum necessary lubricating oil is supplied through an orifice 394 having a smaller diameter. Note that these small diameter orifices 3
Since the amount of pressure oil flowing out from the flow path 2 via 93 and 394 is minute, it hardly affects the maintenance of the secondary line pressure of the flow path 2.

When the engine is operated in a high rotation speed range and there are many discharge oil passages of the oil pump 20, there is a large amount of surplus oil discharged from the primary regulator valve 30 to the oil passage 2 (zone C in FIG. 6).

Since the secondary line pressure becomes higher than the appropriate range, the spool 37 is displaced downward in the figure, the third port 373 and the first port 371 communicate with each other, and pressure oil is supplied from the oil path 8 to the hydraulic servo 203 of the oil pump 20. The amount of oil discharged from the oil pump 20 is reduced,
This acts to reduce excess oil in the primary regulator valve 30 and lower the secondary line pressure to a set appropriate range. By reducing the discharge capacity of the oil pump 20, the output torque of the engine consumed by the oil pump 20 is reduced, making it possible to increase the engine output and improve fuel efficiency.

Note that this secondary line pressure is approximately 1/2 of the primary regulator pressure outputted to the oil passage 1 by the primary regulator valve 30.

The throttle valve 40 has a spool 42 having a spring 41 on its back on one side (upper side in the drawing), and is arranged in series with the spool 42 via a spring 43, and one end 44A (lower end in the drawing) protruding from the valve body is connected to the engine. The throttle plunger 44 is in contact with the operating surface of a throttle cam (not shown) that rotates in accordance with the throttle opening. The throttle plunger 44 is a large diameter land 44 on the upper side in the figure.
In addition to the pressing force from the throttle cam, the throttle pressure of the oil passage 7 is applied to the effective pressure-receiving surface of the large-diameter land 441, thereby increasing the effective pressure-receiving pressure of the lower small-diameter land 442. The surface receives the cutback pressure of the oil passage 7A, is displaced upward in the figure, and is connected to the spool 42 via the spring 43.
Press upward. The spool 42 receives the pressing force from the spring 43 from below, and the spring load from the spring 41 from above is applied to the upper end land 421.
The cutback pressure of the oil passage 7A applied to the effective pressure receiving surface of the intermediate land 4 via the orifice 401
It is displaced in response to the feedback of the throttle pressure applied to the effective pressure-receiving surface of the oil passage 22, increasing or decreasing the communication area between the oil passage 2 and the oil passage 7, and adjusting the secondary line pressure supplied from the oil passage 2 to the throttle opening. The throttle pressure is adjusted to the throttle pressure shown in FIG. 7, which changes in relation to the governor pressure (output shaft rotational speed).

The cutback valve 45 has a large diameter lower end land 46.
1. A spool 46 having an intermediate land 462 and an upper end land 463 is provided, and when the spool 46 is set downward in the figure, the oil passage 7 and the oil passage 7A communicate with each other, and a cutback pressure Pc is generated in the oil passage 7A. The spool 46 receives governor pressure Pg supplied from above to the effective pressure receiving area S1 of the lower end land 461 via the oil passage 6, and receives cutback pressure Pc from below to the pressure receiving area S2 of the lower end land 461 from below via the orifice 451. Pg×S1=Pc
The equilibrium expressed by the equilibrium equation of ×S2 is displaced. As the spool 46 is displaced upward, the area of the oil passage 7A communicating with the oil passage 7 decreases, and the area of the oil passage 7A communicating with the drain port 451 increases, so the cutback pressure Pc decreases and Pg ×S1＞
Since Pc×S2, the spool 46 is moved downward. In this way, the spool 46 is Pg×S1=
The cutback pressure is maintained at a position determined by the balance equation of Pc×S2 and output to the oil passage 7A. Figure 8 shows the cutback pressure Pc characteristics.

The line pressure regulating valve 47 includes a spool 49 having a spring 48 on its back on one side (lower side in the figure). The spool 49 is connected to the spring 48 from below.
The upper end land 49 shown from above receives the load from the bending.
1 is displaced in response to the governor pressure Pg of the oil passage 6, and the communication area between the oil passage 7B that outputs the throttle control pressure, the oil passage 7 to which the throttle pressure is supplied, and the drain port 471 is adjusted, and the oil passage Adjust the throttle control pressure output to 7B.
Figure 3 shows the characteristics of the throttle control pressure Psm.

The reduction ratio control mechanism 50 connects the hydraulic servo 154 of the input pulley 150 and the oil path 1 or the drain port 5.
Controls communication with 11 and V-belt continuously variable transmission 14
A reduction ratio control valve 51 that changes the reduction ratio of 0 is controlled by an electronic control device that receives vehicle running conditions such as input pulley rotation speed and throttle opening.
It consists of an upshift electromagnetic solenoid valve 55 (hereinafter referred to as up solenoid 55) and a downshift electromagnetic solenoid valve (hereinafter referred to as down solenoid 56) 56, which are turned off and control the reduction ratio control valve 51. The reduction ratio control valve 51 has a spring 52 installed behind it on one side (lower side in the figure), and an intermediate land 532 between an upper end land 531 and a lower end land 534 in contact with the upper end of the spring 52.
and 533, and the oil chamber 521 between the lands 531 and 532 communicates with the oil passage 9 and also with the oil passage 1 where the spool 53 is displaced upward, and when the spool 53 is displaced downward. Contact Drainport 511. The oil chamber 522 between the intermediate lands 532 and 533 is the lower end oil chamber 5.
24, which connects with oil passage 12A, which connects with land 532.
The hydraulic pressure in the oil passage 12A is leaked from the drain port 511 whose opening area is adjusted to adjust the pressure and hold the spool at an intermediate position. A notch 511A is provided in the drain port 511 and the oil passage 12 is provided with a notch 511A.
The amount of hydraulic pressure leaking from A changes gradually, and the spool is smoothly maintained at an intermediate position. intermediate land 53
3 and the lower end land 534 communicates with the oil passage 6A via the orifice 512, and when the spool 53 is held at the intermediate position, the oil chamber 523 communicates with the oil passage 6A through the orifice 512.
A and the drain port 513 are connected to the oil passage 6A.
When the spool 53 is displaced upward, the lower end land 534 connects to the communication port 514 with the oil passage 6A.
is closed to maintain the oil pressure in the oil passage 6A, and the communication port 515 of the oil passage 12A, which communicates with the lower end oil chamber 524, is communicated with the drain port 513 to discharge pressure from the oil passage 12A. Up solenoid 55
is attached to the oil passage 2A which is supplied with secondary line pressure from the oil passage 2 via the orifice 551 and communicates with the illustrated upper end oil chamber 525 of the reduction ratio control valve 51, and when it is OFF, the oil pressure of the oil passage 2A is set to high. It is maintained at the same level (equivalent to the secondary line pressure) and discharges the hydraulic pressure in oil path 2A when it is ON. The down solenoid valve 56 communicates with the oil passage 12 via an orifice 561 and also connects to the reduction ratio control valve 51.
A port 515 communicates with the lower end oil chamber 524 of the reduction ratio control valve, and further communicates with the oil chamber 522 of the spool when the spool 53 of the reduction ratio control valve is held in the intermediate position.
It is installed in oil passage 12A that connects to
When it is OFF, the oil pressure in the oil passage 12A is maintained, and when it is ON, the oil pressure in the oil passage 12A is exhausted.

In the above configuration, the primary line pressure of the oil passage 1 is controlled as follows.

When a shift signal for upshifting or downshifting is issued from an electronic control circuit that receives vehicle driving conditions such as input pulley rotation speed and throttle opening as input, the up solenoid 55 or the down solenoid 56 is turned on, and the reduction ratio control valve 51 is turned on.
spool 53 is displaced upward or downward from the intermediate position, thereby cutting off communication between the oil passage 6A and the drain port 513, governor pressure is generated in the oil passage 6A, and the governor pressure in the oil passage 6A is The upper land 3 of the regulator plunger 33 is transmitted as a shift signal oil pressure via the check valve 34 and the oil passage 11.
31 and pushes the spool 32 upward. This shift signal oil pressure reduces the communication area between oil passage 1 and oil passage 2 of primary regulator valve 30. As a result, the line pressure regulated by the regulator valve 30 increases in level as shown by the broken line in FIG.

In this way, during steady running, the input pulley's hydraulic servo is kept constant at a low line pressure, and the line pressure is leveled up only when the torque ratio changes, and this level-up line pressure is supplied to the input pulley's hydraulic servo during upshifts. During a downshift, it is supplied to the hydraulic servo of the output pulley to control the reduction ratio. This allows the V-belt continuously variable transmission to perform rapid upshifts and downshifts, resulting in excellent acceleration and deceleration performance.At the same time, the line pressure remains at a low level when not shifting, and the engine's output is consumed by the oil pump. can be reduced. In this embodiment, a governor pressure that increases as shown in FIG. 3 in response to an increase in the vehicle speed or the rotational speed of the output shaft 142 is used as the shift signal oil pressure. This is because the above-mentioned characteristics of the governor pressure are suitable for obtaining the line pressure required during shifting, but the shift signal oil pressure may be another oil pressure other than the governor pressure.

The shift sequence mechanism 60 consists of a shift sequence valve 61 and check valves 64 and 65.

The shift sequence valve 61 is located on one side (lower side in the figure).
A spring 62 is provided on the back of the upper end land 6 shown in the figure.
31, a spool 63 having an intermediate land 632, a lower end land 633 shown in the figure with which the upper end of the spring 62 is in contact, and a port 611 communicating with the oil passage 1;
A port 61 that communicates with the oil passage 10 for supplying hydraulic oil to the hydraulic servo 164 of the output pulley 160
2. It has a port 613 communicating with the oil passage 12 and a drain port 614. Check valve 64 is connected to oil line 2
The check valve 65 is inserted into an oil passage communicating between the oil passage 2 and the oil passage 10, and the check valve 65 is inserted into an oil passage communicating between the oil passage 2 and the oil passage 12.

The spool 63 of the shift sequence valve 61 is displaced by receiving the spring load of the spring 62 from below and receiving pressure from the oil passage 9 supplied from above through the orifice 601 on the upper end land 631,
When the oil pressure in oil passage 9 is higher than the set value (during steady running or upshifting), the oil pressure in oil passage 1 is set to the lower position in the diagram.
2 and oil passage 10, and oil passage 1 and oil passage 1.
0, and further connects oil passage 1 and oil passage 13. When the oil pressure in oil passage 9 is exhaust pressure (during downshift), the oil passage 1 and oil passage 10 are set upward in the figure.
At the same time, the oil passage 12 is connected to the drain port 614 to discharge pressure, and the oil passage 1 and the oil passage 1
Cut off contact with 3. The check valve 64 functions to supply the secondary line pressure of the oil passage to the oil passage 10 and the oil passage 12 when the spool 63 of the shift sequence valve is set downward in the figure, and the check valve 65 functions to supply the oil pressure of the oil passage 12 to the oil passage 10 and the oil passage 12. When the pressure becomes higher than the oil pressure in the oil passage 2, the pressure oil in the oil passage 12 is discharged to the oil passage 2. FIG. 9 shows changes in the oil pressure P9 of the oil passage 9, the oil pressure P10 of the oil passage 10, and the oil pressure P12 of the oil passage 12 with respect to the output shaft rotation speed.

The input pulley modulator mechanism 66 consists of a modulator valve 67 and a check valve 69. The modulator valve 67 has a spring 6 on one side (lower in the figure).
A check valve 69 is inserted between the output oil path 13A of the modulator valve 67 and the operation supply oil path 9 to the hydraulic servo 154 of the input pulley. The spool 68 of the modulator valve 67 receives the spring load of the spring 671 and the governor pressure supplied from the oil passage 6 from one side, and receives the output oil pressure of the oil passage 13A through the orifice 672 from the other side to the upper end land shown in the figure. The oil passages 13A and 1 are displaced in response to feedback.
3 and the drain port 673, the line pressure supplied from the oil passage 13 is regulated in relation to the governor pressure, and is output to the oil passage 13A as line modulator pressure.

FIG. 10 shows the line modulator pressure Pm and the required pressure Pn required by the input pulley hydraulic servo during steady running.

In the conventional reduction ratio control mechanism, in order to maintain a steady running state, the tension of the V-belt pulled by the input pulley and the output pulley is maintained.
It is necessary to supply hydrostatic pressure that takes into account the hydraulic pressure in the hydraulic servo generated by centrifugal force to the hydraulic servo of each pulley, and to balance the clamping force of the V-belt by the hydraulic servo between the input pulley and the output pulley. However, the rotational speeds of the input pulley and output pulley fluctuate according to the reduction ratio (torque ratio), so in order to achieve the above-mentioned balance, the reduction ratio control mechanism must be operated to supply hydraulic oil to the hydraulic servo of the input pulley or the like. It was necessary to drain hydraulic oil from the input pulley's hydraulic servo. Therefore, even during steady driving, the solenoid valve always operates ON and OFF.
This placed a heavy burden on the solenoid valve, which was disadvantageous from the viewpoint of durability of the electromagnetic solenoid valve.

The input pulley modulator mechanism 66 determines the speed at which the driving force of the engine and the steady-state running resistance are balanced at each throttle opening, and adjusts the hydraulic servo pressure of the input pulley necessary for that state (in steady state) to the reduction ratio control mechanism. Balances the hydraulic servo pressure of the input pulley by supplying it from the input pulley modulator mechanism without going through the
This turns the downshift and upshift electromagnetic solenoid valves ON and OFF when the reduction ratio control mechanism maintains steady running or downshift.
The number of operations is reduced.

Next, the reduction ratio control mechanism 50, the shift sequence mechanism 60, the input pulley modulator mechanism 66, and the primary regulator valve 30 of the hydraulic adjustment device
Explain the effect of

When the vehicle starts from a stop, when the manual valve is set to the N position, both the up solenoid valves 5 are in the OFF state.
5 and the down solenoid valve 56, the down solenoid valve 56 is turned on for a short time by the action of the electronic control circuit that inputs the N-D shift signal of the manual valve.
The spool 53 is set downward in the figure. As a result, the oil passage 9 that supplies hydraulic oil to the input pulley's hydraulic servo 154 communicates with the drain port 511, and its oil pressure is discharged and lowered. When the oil pressure in the oil passage 9 decreases and reaches the set value, the spool 63 of the shift sequence valve 61 is displaced upward in the figure by the action of the spring 62, and the oil is supplied to the oil passage 1 and the hydraulic servo 164 of the output pulley. The oil passage 10 is connected to supply primary line pressure to the oil passage 10, and at the same time, the oil passage 12 and the drain port 614 are connected to exhaust pressure from the oil passage 12. As the primary line pressure is supplied to the oil passage 10, the hydraulic servo 164 of the output pulley quickly increases the effective diameter of the output pulley to the maximum value, and the tension of the V-belt 145 due to the increase in the effective diameter of the output pulley causes The movable flange of the input pulley is pushed and moved, and the hydraulic servo 15
The effective diameter is reduced to the minimum value while promoting the drainage pressure of the hydraulic oil in 4. At the same time, the oil passage 12A communicates with the drain port 513 and is evacuated, and the oil passage 12 is also evacuated, so that the evacuated pressure state is maintained regardless of whether the down solenoid valve 56 is ON or OFF. The throttle control pressure in the oil passage 7B is applied to the primary regulator valve 30 via the oil passage 11.
The pressure is input to the regulator plunger 33 to raise the level of the primary line pressure. This level-up primary line pressure is supplied to the hydraulic servo 164 of the output pulley as described above.
The effective diameter of the output pulley 160 increases quickly and strongly, making it possible to start the vehicle smoothly.

When the vehicle is upshifted after starting or during a rapid upshift while the vehicle is running, the up solenoid valve 55 is turned on and the down solenoid valve 56 is turned off. As a result, the spool 53 of the reduction ratio control valve 51 is set upward in the figure, and the oil passage 9 and the oil passage 1 communicate with each other. Since the primary line pressure is supplied to the oil passage 9, the spool 63 of the shift sequence valve 60 is displaced downward in the figure.
Communication between oil passage 10 and oil passage 1 is cut off, and communication between oil passage 10 and oil passage 12 is established. Therefore, the check valve 64 is supplied to the oil passage 10 with the secondary line pressure of the oil passage 2. In a V-belt type continuously variable transmission, the hydraulic servo 154 of the input pulley, which is supplied with primary line pressure from oil path 9, is connected to oil path 1.
The load is larger than the hydraulic servo 164 of the output pulley to which secondary line pressure is supplied from 0, the effective diameter of the input pulley 150 increases, and the output pulley 1
The effective diameter of 60 is reduced and upshifted. The secondary line pressure supplied to the oil passage 10 is guided to the oil passage 12A via the oil passage 12, and allows the down solenoid valve 56 to control the oil pressure of the oil passage 12A. Also, since the spool 53 is set upward in the figure, the oil passage 6A and the drain port 51
3 is cut off by the land 534, the governor pressure of the oil passage 6A is maintained, and the oil passage 6A
The governor pressure is input to the regulator plunger 33 of the primary regulator valve 30 to raise the level of the primary line pressure as shown in FIG. Since this level-up primary line pressure is supplied to the input pulley hydraulic servo 154 as described above, the effective diameter of the input pulley 150 increases quickly and strongly, allowing the vehicle to shift up rapidly and achieve excellent acceleration performance. A continuously variable automatic transmission for a vehicle is obtained.

During steady running, both the up solenoid valve 55 and the down solenoid valve 56 are turned off.

The spool 53 of the reduction ratio control valve 51 is held at an intermediate position, the oil passage 9 is cut off from both the oil passage 1 and the drain port 511, and the oil pressure is maintained.
As a result, the spool 6 of the shift sequence valve 61
3 is held at the bottom in the figure. In this state, hydraulic oil is supplied to the oil passage 9 from the oil passage 12B through the check valve to replenish the leakage of hydraulic oil in the oil passage 9 or to slightly change (increase) the reduction ratio as the output shaft rotational speed increases. This is done by the input pulley modulator valve via the input pulley modulator valve 69, and is done without turning on or off the up solenoid valve 55 or the downshift valve 56. As a result, the up solenoid valves 55 and 5
6 durability can be improved.

During a normal upshift and a gradual upshift, the up solenoid valve 55 is intermittently turned ON and OFF by the output of the electronic control device, and the spool 53 of the reduction ratio control valve is vibrated upwardly displaced in oil passages 1 and 9. There is also communication between the two over a small area. As a result, the oil pressure in the oil passage 9 increases, and the hydraulic servo 154 of the input pulley connected to the oil passage 9 increases the effective diameter of the input pulley in accordance with the amount of hydraulic oil supplied from the oil passage 1 to the oil passage 9. and an upshift is performed.

During a normal downshift and a gradual downshift, the down solenoid valve 56 is intermittently turned ON and OFF by the output of the electronic control device, and the spool 53 of the reduction ratio control valve is vibrated downward, and the drain port 511 and oil passage It also communicates with 9 through a small communication area. As a result, the oil pressure in the oil passage 9 decreases, and the oil pressure in the oil passage 9 decreases.
The hydraulic servo 154 of the input pulley connected to the input pulley reduces the effective diameter of the input pulley in accordance with the amount of hydraulic oil discharged from the oil passage 9 to the oil passage 511, thereby performing a downshift.

During a sudden downshift, the up solenoid valve 55 is turned OFF, and the down solenoid valve 56 is turned ON or OFF. As a result, the spool 53 of the reduction ratio control valve 51 is set downward in the figure, and the oil passage 9 communicates with the drain port 511. The pressure in the oil passage 9 is exhausted, and as a result, the shift sequence valve 61 is activated so that the spool 63 is connected to the spring 6.
2, the oil passage 10 is set upward in the figure, and the oil passage 1
The primary line pressure is supplied to the hydraulic servo 164 of the output pulley, and the oil passage 12 is connected to the drain port 614 for exhaust pressure. In the V-belt type continuously variable transmission 120, the effective diameter of the output pulley 120 rapidly increases due to the primary line pressure being supplied to the hydraulic servo of the output pulley, and as the effective diameter increases, the V-belt 14
With a tension of 5, the movable flange of the input pulley is pushed and moved, reducing the effective diameter while promoting the discharge pressure of the hydraulic fluid of the hydraulic servo 154. At this time, oil passage 12
Since A communicates with the drain port 513 and is depressurized, the depressurized state is maintained regardless of whether the downshift solenoid valve 56 is turned on or off. Furthermore, since the spool 53 is set downward in the figure, the communication between the oil passage 6A and the drain port 513 is blocked by the land 533, so the governor pressure of the oil passage 6A is maintained, and the governor pressure of the oil passage 6A is The pressure is input to the regulator plunger 33 of the primary regulator valve 30, and the primary line pressure is leveled up as shown in FIG. Since this level-up primary line pressure is supplied to the output pulley hydraulic servo 164 as described above, the effective diameter of the output pulley 160 increases rapidly and strongly, and the vehicle is rapidly accelerated.

The manual valve 70 includes a spool 71 that is manually displaced by a shift lever provided on the driver's seat. ),
L
(Low), and at each shift position, oil passages 1 and 2 are connected to oil passages 3 and 4 as shown in Table 1, and a line is connected to oil passages 3 and 4. pressure or secondary line pressure, or connect oil passage 3 or oil passage 4 with drain port 701 or 702 to exhaust pressure. In addition, the drain port 702 that drains pressure from the oil passage 4 that communicates with the clutch C1 is set so that its opening is above the oil level 712 to prevent the clutch from dragging due to residual oil in the hydraulic servo of the clutch C1. ing.

Table 1 P R N D L Oilway 3 × 〇 × × × Oilway 4 × × × △ △ In Table 1, 〇 indicates communication with oilway 1, △ indicates communication with oilway 2, and × indicates communication with oilway 2. Indicates exhaust pressure.

The shift control mechanism 75 includes a shift control valve 76;
Secondary line pressure is supplied from the oil passage 2 via an orifice 91, which is attached to the oil passage 2D that communicates with the oil chamber at the left end in the diagram of the shift control valve 76, and controls the shift control valve 76 according to the output of the electronic control device. It consists of a shift control electromagnetic solenoid valve (hereinafter referred to as shift solenoid valve) 79. The shift control valve 76 is provided with a spring 77 on one side (right side in the figure), and has a left end land 781 in the figure and an intermediate land 78.
2 and 783, and a spool 78 having a small diameter and a right end land 784 in the figure, to which the left end of the spring 77 is abutted. The spool 78 receives the hydraulic pressure of the oil passage 2D on the land 781 from the left side, and receives the spring load of the spring 77 and the hydraulic oil supply/drain passage 3a to the hydraulic servo 122 of the brake B1 from the right side.
From the effective pressure receiving area of land 783 (land 783
(cross-sectional area of the land 784 - cross-sectional area of the land 784) or the feedback of the hydraulic pressure received from the land 784 from the hydraulic oil supply/discharge passage 4a to the hydraulic servo 121 of the clutch C1.

Next, the functions of the manual valve 70 and the shift control mechanism 75 will be explained.

When the manual valve is shifted from the N position (range) to the D range, the oil passage 3 becomes a discharge pressure state and the secondary line pressure is supplied to the oil passage 4. The N→D shift signal causes the shift solenoid valve 79, which had been turned off during the N range, to be turned on for a set short time, thereby setting the spool 78 to the left in the figure. At this time, the oil passage 4 and the oil passage 4a are cut off, the oil passage 4a is connected to the drain port 761, and the pressure is discharged, and the clutch C1 is released. . The duty control turns ON and OFF so that the ON time gradually decreases, and the oil pressure of the oil passage 2D is gradually increased. As a result, the spool 78 is gradually displaced to the right in the figure, and the oil passage 4a has a communication area with the oil passage 4. The area of communication with the drain port 761 is increased, and the communication area with the drain port 761 is decreased.
The oil pressure at a smoothly approaches the secondary line pressure. In this way, a smooth N→D shift is performed. Shift solenoid valve after a certain period of time 7
9 is turned off.

When the manual valve is shifted from N range to R range, primary line pressure is supplied to oil path 3 and oil path 4
maintains the exhaust pressure state. In response to the N-R shift signal, the shift solenoid valve 79, which was turned off in the N range, is turned on and off so that the off time is gradually reduced by the duty control, whereby the oil pressure in the oil passage 2D gradually decreases. As a result, the spool 78, which had been set to the right in the drawing, is gradually displaced to the left in the drawing, and the communication area of the oil passage 3a with the drain port 761 is gradually decreased, and the communication area with the oil passage 3 is gradually increased, resulting in a smooth N. →R shift is performed. Fixed time shift solenoid valve 79
is turned on.

When the solenoid valve 77 is turned on, pressure is discharged from the oil passage 2D, so the spool 78 is set to the left in the figure and communicates with the oil passage 3 and oil passage 3a, and pressure oil is supplied to the hydraulic servo 122, which then operates the brake B1. When engaged, the oil passage 4a communicates with the drain port 761 and is discharged, and the clutch C1 is released. As a result, the planetary gear transmission mechanism 120 enters the reverse traveling state. Furthermore, when the solenoid valve 79 is turned OFF, the oil pressure in the oil passage 2D becomes the secondary line pressure, and the spool 78 is set to the right in the figure, and the oil pressure in the oil passage 2D becomes the secondary line pressure.
is connected to the oil passage 4a, and the oil passage 3a is connected to the drain port 761. As a result, pressure oil is supplied to the hydraulic servo 121, pressure is discharged from the hydraulic servo 122, the clutch C1 is engaged, and the brake B1 is released. As a result, the planetary gear transmission mechanism 120
is in the forward state.

Furthermore, when the vehicle speed is below the set speed and the throttle opening is below the set throttle opening while driving in the D range, the shift solenoid valve 79 is turned ON by the output of the electronic control device, thereby releasing the clutch C1, and connecting the input shaft and output shaft of the planetary gear transmission. By breaking the connection between the two, it is possible to run inertia, thereby improving fuel efficiency.

The lock-up control mechanism 80 includes a lock-up control valve 81, a lock-up signal valve 85, and a lock-up electromagnetic solenoid valve 8 as an auxiliary device.
It has 8.

The lock-up control valve 81 includes a spool 82 disposed at the bottom in the figure, and a plunger 8 disposed in series with the spool 82 via a spring 83.
4. The spool 82 has a lower end land 821, an intermediate land 822, and an upper end land 823 shown in the figure, each having the same diameter, and the plunger 84 is set to have a smaller outer diameter than the land of the spool 82.

The lock-up signal valve 85 has a spool 87 with a spring 86 on its back. When the oil passage 2 receives the hydraulic pressure of the oil passage 10 from the other side and is displaced and set upward in the figure
and the oil passage 2B, and when the oil passage 2B is set downward in the drawing, the communication between the oil passage 2B and the oil passage 2 is cut off, and the oil passage 2B is connected to the drain port 851.

The lock-up electromagnetic solenoid valve 88 is connected to the oil path 2.
C, when it is turned ON, the hydraulic pressure of the oil passage 2C is discharged and the spool 87 of the lock-up signal valve 85 can be displaced by the change in the oil pressure of the oil passage 10, and when it is turned OFF, the oil pressure of the oil passage 2C is discharged. Hold it to lock the spool 85 of the lock-up signal valve 85 upward in the figure.

Next, the operation of the lockup control mechanism 80 will be explained.

The lock-up control valve 81 receives an input signal hydraulic pressure for controlling the release and engagement of the direct coupling clutch through the oil passage 2, the lock-up signal valve 85, and the oil passage 2B on the pressure-receiving surface of the illustrated lower end land 821 of the spool 82. A secondary line Ps is applied to the pressure receiving area L2 (pressure receiving area L2), and a hydraulic pressure P10 of the hydraulic servo 164 of the output pulley is applied as a counter hydraulic pressure from the oil passage 10 to the pressure receiving surface of the plunger 84 (pressure receiving area L1).

(a) When the hydraulic pressure of the hydraulic servo 164 of the output pulley is the primary line pressure P1, this lock-up control valve 81 receives the pressure of the spool 82 and plunger 84 so that P10・L1>Ps・L2 since P10=P1. The area is set. Therefore, the oil pressure D10 of the oil passage 10
is the primary line pressure P1, the spool 82 is fixed to the direct clutch release side, and the input signal oil pressure (secondary line pressure Ps)
Regardless of the above, the oil passage 5A and the oil passage 5C are connected, and the oil passage 5D and the oil passage 5F are connected. The hydraulic oil flows in the order of oil passage 2 → secondary regulator valve 35 → oil passage → oil passage 5A → lock-up control valve 81 → oil passage 5C → oil passage 5D → lock-up control valve 81 → oil passage 5F → oil cooler, and is directly connected. Clutch 108 is released.

(b) When the hydraulic pressure of the output pulley's hydraulic servo 164 is the secondary line pressure, the spool 82 is set upward in the figure (direct coupling clutch engagement side) due to the relationship P10=Ps P10・L1<Ps・L2, and the spool 82 is set upward in the figure (direct coupling clutch engagement side) and oil road 5
D and the oil passage 5C communicate with the drain port 811. Hydraulic oil goes through oil path 2 → secondary regulator valve 35 → oil path 5 → oil path 5A
→ Lockup control valve 81 → Oil passage 5D → Oil passage 5
C→Drain port 81 of lock-up control valve
1, the lock-up clutch engages. FIG. 11 shows the relationship between the position of the spool of the lock-up control valve 81 and the oil pressure P2B in the oil passage 2B and the oil pressure P10 in the oil passage 10, and FIG. 12 shows the characteristics of P2B and P10 with respect to vehicle speed.

The lock-up signal valve 85 has a pressure receiving area L
The hydraulic pressure of the oil passage 10, which is the hydraulic pressure of the hydraulic servo 164 of the output pulley, is shown from above on the spool 87 of
P10 is applied to the spring 86 from below in the figure.
The spring load SP2 and the secondary line pressure Ps of the oil passage 2C connected to the oil passage 2 via the orifice 881 are applied.

(c) Oil pressure P10 of oil passage 10 is primary line pressure P1
When , the spring load is set so that the relationship is P10=P1 P10・L>Ps・L+SP2, so the spool 87 is set downward in the figure, and the oil path 2
The communication between the oil passage 2B and the oil passage 2B is cut off, and the oil passage 2B and the drain port 851 are connected.
The pressure in the oil passage 2B is exhausted. Due to this exhaust pressure in the oil passage 2B, the spool 82 is set downward in the figure, and the direct coupling clutch 108 is released. That is, oil passage 10
When the oil pressure of 8 is the primary line pressure, the input signal oil pressure (the oil pressure of oil passage 2B) is the lock-up control valve 8.
1, the direct coupling clutch 108 is released regardless of other conditions.

By the way, as is clear from FIG. 9, the oil pressure in the oil passage 10 is high when the rotational speed of the output shaft of the V-belt type continuously variable transmission is a small value below a predetermined value, in other words, at a low vehicle speed below a predetermined vehicle speed. Therefore, at low vehicle speeds below this predetermined vehicle speed, the direct coupling clutch 108 will not engage regardless of other conditions. As a result, due to the malfunction, the control hydraulic pressure, which is a lock-up signal, is sent from the lock-up signal valve 85 to the oil path 2.
When input to lockup control valve 81 through B, engagement of direct coupling clutch 108 is reliably prevented.

(d) Oil pressure P10 of oil passage 10 is secondary line pressure
When Ps, P10=Ps P10・L<Ps・L+SP2, so the spool 87 is set upward in the figure, and the oil path 2B communicates with the oil path 2 to provide secondary line pressure.
Ps is supplied.

Therefore, the force applied to the spool 82 of the lock-up control valve 81 that biases the direct coupling clutch 108 toward the engagement side is greater than the force that biases the direct coupling clutch 108 toward the disengagement side. It is set on the engagement side of the direct coupling clutch 108.

(e) When the lock-up solenoid 88 is turned on, the spool 87 is fixed at the lower position in the figure regardless of the oil pressure in the oil passage 10, as described above, and the oil passage 2
B is exhausted, no input signal oil pressure is supplied to the lock-up control valve 81, and the direct coupling clutch 108 is released. Therefore, the lock-up control valve 8
1 is only when the vehicle speed is above a predetermined speed and there is an input signal oil pressure (lock-up-on signal) in the oil path 2B.
The direct coupling clutch 108 is now engaged. An orifice 5G is provided between the oil passage 5D and the oil passage 5F to constantly supply the minimum amount of hydraulic oil necessary to prevent the oil temperature from rising excessively to the oil cooler.

FIG. 13 shows another embodiment. In this embodiment, the reduction ratio control valve 51 is not provided with an input pulley modulator mechanism. Similar to the reduction ratio control mechanism in the hydraulic control device shown in FIG. 2, the reduction ratio control mechanism of this continuously variable automatic transmission for a vehicle also achieves downshifting and low gear running without operating the down solenoid.

As described above, according to the reduction ratio control device for a continuously variable automatic transmission for vehicles of the present invention, the control is performed by the control hydraulic pressure using the hydraulic oil from the oil pump, and the supply and discharge of hydraulic pressure to each of the hydraulic servos is controlled by the control hydraulic pressure using the hydraulic oil from the oil pump. upshift electromagnetic solenoid means for controlling the control hydraulic pressure so as to set the reduction ratio control means to the upshift side; downshift electromagnetic solenoid means for controlling control hydraulic pressure; and when the control hydraulic pressure is controlled by the operation of the downshift electromagnetic solenoid means and the reduction ratio control means is set to the downshift side, hydraulic oil from the oil pump is Since a holding means is provided to hold the reduction ratio control means on the downshift side by cutting off the control hydraulic pressure caused by the Even if the electromagnetic solenoid means is deactivated by stopping the energization, the control hydraulic pressure from the hydraulic oil from the pump is cut off by the holding means, and the reduction ratio control means is held on the downshift side. Therefore, the hydraulic oil from the pump is not discharged unnecessarily, and oil pump loss is reduced. Furthermore, while the reduction ratio control means is being set to the downshift side, the downshift electromagnetic solenoid means does not need to be energized all the time, so the durability of the electromagnetic solenoid means is improved.

[Brief explanation of drawings]

Figure 1 is a skeleton diagram of a continuously variable automatic transmission for vehicles, Figure 2
The figure is a hydraulic circuit diagram of the hydraulic control device, FIG. The figure is a graph showing the primary line pressure characteristics by the hydraulic pressure adjustment device in the hydraulic control device of the continuously variable automatic transmission for vehicles of the present invention, and Fig. 5 is the hydraulic pressure adjustment in the hydraulic control device for the continuously variable automatic transmission for vehicles of the present invention. A graph showing the secondary line pressure characteristics by the device, Fig. 6 a graph showing the output oil pressure characteristics from each port of the secondary regulator valve, Fig. 7 a graph showing the throttle pressure characteristics output from the throttle valve,
Figure 8 is a graph showing cutback pressure characteristics, Figure 9 is a graph showing cutback pressure characteristics.
The figure is a graph showing the input and output oil pressure characteristics of the shift sequence valve, and Figure 10 is a graph showing the characteristics of the line modulator pressure Pm output from the input pulley modulator valve and the required oil pressure Pn of the input pulley.
Fig. 11 is a graph showing the relationship between the spool position of the lock-up control valve and the input signal oil pressure and counter oil pressure. Fig. 12 is a graph showing the characteristics of the input signal oil pressure and counter oil pressure of the lock-up control valve with respect to vehicle speed. Fig. 13 FIG. 2 is a hydraulic circuit diagram showing another embodiment of a reduction ratio control mechanism for a continuously variable automatic transmission for a vehicle according to the present invention. In the figure, 20...variable volume oil pump, 25
...Governor valve, 30...Primary regulator valve, 35...Secondary regulator valve, 40...
... Throttle valve, 45 ... Cutback valve, 47
... Line pressure regulating valve, 50 ... Reduction ratio control mechanism,
51... Reduction ratio control valve, 55... Upshift electromagnetic solenoid valve, 56... Downshift electromagnetic solenoid valve, 60... Shift sequence mechanism, 61
...Shift sequence valve, 66...Input pulley modulator mechanism, 67...Modulator valve, 3
4,64,65,69...check valve, 70...
Manual valve, 75...Shift control mechanism, 76...
...Shift control valve, 79...Electromagnetic solenoid valve for shift control, 80...Lockup control mechanism, 81
... Lockup control valve, 85 ... Lockup signal valve, 88 ... Lockup electromagnetic solenoid valve, 100 ... Torque converter, 120 ...
Planetary gear transmission mechanism for forward/reverse switching, 140...
V-belt continuously variable transmission, 150...input pulley,
160...Output pulley, 170...Differential gear, 180...Output gear, 190...Chain.

Claims (1)

[Scope of Claims] 1 Consists of an input pulley, an output pulley, and an endless belt stretched between these input and output pulleys, and the effective frictional engagement position between each pulley and the endless belt In a continuously variable automatic transmission for a vehicle that performs continuously variable speed by changing the diameter using a hydraulic servo, the hydraulic pressure is controlled by the control hydraulic pressure from hydraulic oil from an oil pump, and the hydraulic pressure to the hydraulic servo is controlled by hydraulic pressure from the hydraulic oil from an oil pump. a reduction ratio control means for controlling supply and discharge; an upshift electromagnetic solenoid means for controlling the control hydraulic pressure so as to set the reduction ratio control means to an upshift side;
A downshift electromagnetic solenoid means for controlling the control hydraulic pressure so as to set the reduction ratio control means to the downshift side, and the control oil pressure is controlled by the operation of the downshift electromagnetic solenoid means to shift the reduction ratio control means down. A holding means for holding the reduction ratio control means on the downshift side by cutting off control hydraulic pressure by hydraulic oil from the oil pump when the gear ratio control means is set on the downshift side. Reduction ratio control device for automatic transmission. 2. The holding means inputs the hydraulic pressure of the hydraulic servo of the input side pulley, and when this input hydraulic pressure is below a set value, the shift sequence controls the control hydraulic pressure so as to hold the reduction ratio control means on the downshift side. The reduction ratio control device for a continuously variable automatic transmission for a vehicle according to claim 1, wherein the reduction ratio control device is a valve.