JPS604659A - Hydraulic controller for continuously variable transmission - Google Patents

Abstract

PURPOSE:To improve the fuel consumption by branching a drain circuit from a line pressure circuit while providing a valve openable only under idling and a check valve for setting the line pressure to the minimum necessary level in the drain circuit. CONSTITUTION:A drain circuit 39 is branched from a line pressure circuit 40 while a valve 65 to be controlled by the signals from a rotary sensor 66 and a throttle switch 67 and opens only under idling and a check valve 62 for setting the line pressure to the minimum necessary level are provided in series. Consequently, the delivery pressure and the driving load of an oil pump 37 can be reduced under idling even if the speed change ratio is at the maximum. Consequently, the idlin operation of engine is stabilized to improve the fuel consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a belt-type continuously variable transmission for vehicles.
- Automatically stepless while converting boolean ratio * * 1
Regarding the hydraulic control device that performs the lil f311, in particular, the oil pump that is directly driven by the engine is used as the power source. i' ”) ” J5 in case A, which reduces the engine load associated with driving the oil pump during idling.

' Regarding the hydraulic control system for this type of continuously variable transmission, conventionally, for example, Japanese Patent Application Laid-Open Nos. 54-157930 and 1987-66
There is a prior art in each of the publications of 553, in which the discharge hydraulic pressure of the oil pump is regulated by a pressure regulating valve and acts on the sub pulley side. The control valve is configured to also act on the main pulley side to control the boolean ratio, that is, speed change.

In particular, for the pressure regulating valve, the line pressure is raised at low speeds where the pulley ratio is large and the transmission torque is large, as shown by the solid line in Figure 3, depending on the relationship between the actual gear ratio, auxiliary pulley revolution oil pressure, and engine speed. , the pressure is regulated so that the line pressure decreases as the pulley ratio moves to a high speed stage.

The pulley pushing force required to transmit the maximum torque of the engine at each gear ratio, that is, the FJ friction force between the belt and the bobbin, is reduced by 1q.

Therefore, when J3 is in idle link operation, the engine speed is very low and the gear ratio is maximized by draining oil from the gear change control valve r main pulley, so the line pressure is maximized by the pressure regulating valve. Pump drive load is highest. Therefore, in the case where the oil pump is directly driven by the engine, the pump drive load mentioned above is largely effective when the engine output is low during idling, and in order to maintain stable idling operation, the slot opening must be adjusted to compensate for the pump drive load. - It is necessary to increase the number of holes in the fuel tank, and this has the problem of poor fuel efficiency.

The present invention has been made in view of the problems associated with the conventional technology's speed change control that maximizes the speed ratio during idling. The object of the present invention is to provide an oil drain control system for a continuously variable transmission that reduces the load, stabilizes idling operation of one engine, and improves fuel efficiency.

For this reason, in the Eff system according to the present invention, when the clutch is in the idle state, the clutch at the front stage of the continuously variable transmission is disengaged, and the pulley and belt remain stationary to transmit power.
Focusing on the fact that line pressure is not required to maintain the pulley pressing force necessary for torque transmission, we installed an on-off valve in the drain circuit that branches from the line pressure circuit on the oil pump's discharge side and checked the minimum required pressure. The idea is to install a valve to reduce the line pressure to the minimum required pressure during idling determined by the engine speed and throttle opening, reducing the drive load as well as the oil pump discharge pressure. It is something to do.

Hereinafter, one embodiment of the present invention will be explained in detail with reference to the drawings.
I will clarify. First, as an example of a continuously variable transmission to which the present invention is applied in FIG. 1, a continuously variable transmission with an electromagnetic powder clutch will be described. The step-change transmission@2 is roughly divided into a forward/reverse switching section 3, a bell 1-type continuously variable transmission section 4, a final reduction section 5, and a hydraulic control section 6.

In the electromagnetic powder clutch 1, a drive member 9 with a built-in coil 8 is integrally connected to a crankshaft 7 from the engine, and a driven member 11 is integrally connected in the rotational direction by a spline to a transmission input shaft 10. The drive and driven members 9 and 11 are loosely fitted through the gap 12 so that the powder chamber 13rF'3 accumulates electromagnetic powder i in the gap 12.

Further, a slip ring 15 is installed on the drive member 9 via a holder 14, and a TT is supplied to the slip ring 15.
The brush 1G for i is in sliding contact so that the clutch current flows through the coil 8.

In this way, the electromagnetic powder is chained in the gap 12 between the coil 8 and the driven members 9 and 11 due to the magnetic lines of force generated between the clutch current and the driven members 9 and 11, resulting in a loss of ν, which causes the coupling force to increase the drive. The driven member 11 slides and meshes with the member 9, resulting in a C-connected state. On the other hand, when the clutch current is cut to 1, the driving force caused by the electromagnetic powder and the coupling force between the driven members 9 and 11 disappear, and the clutch becomes disconnected. In this case, if the supply of clutch current and the clutch operation are performed in conjunction with the operation of the switching section 3 of the continuously variable transmission 2 with a shift lever, etc., it is possible to move from P (parking) to N to neutral). to D (drive), L (0-) or R (reverse)
Clutch 1 automatically disconnects and disconnects when switching to range.
Clutch pedal operation becomes unnecessary.

Next, in the continuously variable transmission 2, the switching section 3 is installed between the input horn shaft 10 from the clutch 1 and the main shaft 17 of the continuously variable transmission section 4 disposed coaxially therewith. A reverse drive gear A718 integrally coupled to the shaft 10 and a reverse driven gear 19 rotatably fitted to the main shaft 17 are meshed with each other via a counter gear 20 and an idler gear 21, and these main shaft 17 gears A718.19 A switching clutch 22 is provided between the two.

Then, from the neutral position of the P or N range, the switching clutch 22
When engaged with the gear 18 side, the main shaft 11 is directly connected to the input shaft 10 and the forward state is set to the D or L range, and the switching clutch 2 is engaged.
2 is engaged with the gear 19 side, the power of the input shaft 10 is reversed by the gears 718 to 21 to bring the vehicle into the R-range reverse state.

In the continuously variable transmission section 4, a counter shaft 23 is arranged parallel to the main shaft 17, and a main pulley 24 is connected to both shafts 17 and 23, respectively.
, the sub-pulley 25 is installed, and between the pulleys 24 and 25]: the endless drive bell [-26 is the loop passing]. Both pulleys 211.25 are configured in two parts,
Hydraulic servo mounting surfaces 27 and 28 are provided on the movable pulley half-rests 24a and 25a to make the pulley interval variable.

In this case, the main pulley 24 is fixed side boo
4b, the movable pulley half-rest 24a is moved closer to the fixed-side boom 25b, and the pulley interval is gradually changed. By changing the ratio of the diameters of the pulleys 24 and 25 of the drive belt 26 and the pulleys 24 and 25 of the drive belt 26, continuously variable power is taken out to the subshaft 23.

In the punch reduction unit 5, a large-diameter Noah-Inorgi V732 meshes with an output key A731 of an output shaft 30 connected to the side @23 via an intermediate reduction gear A729, and this final gear A73
2 to the left and right drive wheel axles 34°3j) via a differential 4jlI transverse 33.

Further, the hydraulic control unit 6 is directly connected to the engine crankshaft 7 by passing through the main shaft 11 and the input @ 10 to the main pulley 24 side. A hydraulic pump 37 is installed so that oil pressure is always generated by a pump drive shaft 36 during engine operation.The pump oil pressure is controlled by a hydraulic control circuit 38 based on throttle opening, engine speed, etc. 39.4
0 to each hydraulic servo device 2 on the main pulley and sub pulley side.
7.28, and is configured to perform continuously variable speed control of the continuously variable transmission section 4.

To explain the speed change control system in Fig. 2, in the hydraulic servo device 27 on the main pulley side, the main pulley movable side half 24a is fitted into the cylinder 27a, which also serves as a piston, and is operated by the line pressure of the servo chamber 27b. Even if J5 is in the hydraulic valve device 28 on the sub-pulley side, the sub-pulley movable side half-rest 25a is in contact with the cylinder 28a, and the V-bow chamber 28
b, in which case half 2
The pressure receiving area of line-in pressure is larger in case 4a than in case 25a. The oil passage 40 from the sub-pulley nervo chamber 28b is connected to the A oil hydraulic pump 37. which is directly driven by the engine. A pressure regulating valve 43 and a speed change control valve 44 are provided in an oil passage 39 that communicates with an oil reservoir 42 via a filter 41, branches from the oil pump discharge side of this oil passage 40, and communicates with the main pulley 1 novo chamber 27b. ing.

The speed change control valve 44 includes a valve body 45, a spool 4G, and a spool.

The spool 4G consists of a spring 41 that is biased by one force of the spool 4G and an operating member 48 that changes the spring force.
The pitot pressure of the rotary spring 49/p+, which is mounted on the main spring side and detects the engine speed, is guided to the bow 145a on the opposite side of the G spring 41 via the oil passage 5o.
The actuating member 48 is in contact with a thrower cam 51 that rotates -C depending on the throttle opening. In addition, the valve body 45
Boat 45b has spool 4G and land 46a.

46(), the line pressure supply boat 45c and the drain boat 45 (boat 451) are selectively communicated with one of the line pressure supply boats 45c and drain boat 45 (boat 451), and the boat 45G is communicated with the pressure W4 regulating valve 43 side through the oil passage 39b, and 45G is connected to the drain port T.
d is oil road! i21: Connects to the oil sump side.

As a result, on the spool 46 of the speed change control valve 44, the pitot pressure corresponding to the engine speed of the board 45a and the spring force corresponding to the throttle opening caused by the rotation of the throttle cam 51 act against each other. However, the operation depends on the relationship between these two. In other words, the higher the engine speed,
The smaller the throttle opening is, the more the boats 45b and 45c communicate with each other to introduce line pressure into the main valve-relief chamber 27b, thereby reducing the gear ratio and shifting to a high speed gear.

Next, the pressure regulating valve 43 includes a valve body 53, a spool 54,
It consists of a spring 55 and a spring 5 of a spool 54.
The pitot pressure of the oil passage 50 and the line-in pressure of the oil passage 39c are guided to the bows 1-53a and 53Ll on the opposite side from the main pulley movable half 24a to the spring 55, respectively.
A doppler link 5G is connected to detect the actual gear ratio. Furthermore, oil on the pump side j71.39
c always communicates with the oil passage 39b on one side of the speed change control regardless of the position of the spool 54. Moreover, the oil passage 52 on the drain side also communicates with the boat 53d. The spool 54 is caught in the force of pitot pressure and spring! [It is moving slightly to the right, and the line pressure is regulated by controlling the communication between the line pressure boat 53c and the drain side oil passage 52 due to the missing part of the run 1548 of the spool 54. .

As a result, the sprue 54 of the pressure regulating valve 43 has a pitot.
The sum of pressure and line pressure acts against the spring force of the actual gear ratio (-1), and the operation is based on these relationships.In other words, when the engine speed is 1-yI
+Si, Pi1--The pressure is high and the gear ratio shifts to the high speed side, causing the spring 5 of the feedback link 56;
When the push force decreases, the pitot pressure increases to 54.
When the line pressure is low, the spool 54 moves to the left and the oil passages 39c and 52 are connected to each other. is connected, and the line pressure is regulated so as to drop by draining a portion, reducing the line pressure to the required oil pressure on the high speed stage side.

In addition, the thrower 1 due to the throttle being fully opened when the engine is down by 1
-The action of the pulley cam 51 and the decrease in engine rotation (when the main pulley servo chamber 27b is drained by the shift control valve 44 and the shift to the lower gear side is performed)
G increases the spring front wheel of the pressure regulating valve 43, closes the communication from the oil passage 39c to the oil passage 52, and adjusts the pressure to increase the auxiliary pulley servo oil pressure, thereby achieving the required line pressure on the low speed side. Therefore, a pulley pressing force that does not cause belt slip is obtained with respect to the transmitted torque corresponding to each gear ratio between the low speed gear and the high speed gear.

In this configuration, a drain oil passage 60 is further connected to the oil passage 52 from the oil passage 39c of the discharge side line pressure circuit of the A-il pump 37, and an electromagnetic on-off valve 61 is provided in the oil passage 60.
A check valve 62 is installed (pulled).The on-off valve 61 is connected to the spring 64 when the solenoid G3 is energized.
The check valve 62 maintains a minimum required pressure sufficiently lower than the line pressure regulated by the pressure regulating valve 43 during shift control. The spring force is prescribed to be set. And rotation sensor + J6G that turns on at idle speed
, and when the switch is turned on during the idle period, the switch 67 is electrically connected to the solenoid 63 of the electromagnetic on-off valve 61 indicated by -F via the control circuit 68 of the AND gate. It is connected to the.

Because of this configuration, during idle link, the line pressure discharged from the sub-boot and reservo chamber 28bk:A oil pump 37 is introduced, whereas the line pressure discharged from the main pulley 24 side i 27b is discharged by the speed change control valve 44. This causes the drive belt 26 to reach its maximum position on the main pulley 24 side.
Wind it up, and set the low gear with the maximum gear ratio along with the boolean ratio.

On the other hand, at this time, the il Q of the pressure regulating valve 43 (and the spring 5! by the feedback link 5G) is increased, and as a result, the land 5411 of the spool 54 closes the oil passage 52 on the drain side, and the oil passage 40°3 ! lc,
3 The pressure is adjusted to increase the internal pressure.

However, when idling like C1: [Since the engine rotation speed is no idle rotation, the rotation sensor 6G is turned on,
1) When the dollar opening is in the idle position, 1] 1-
The idle state is detected by turning on the switch G7, and the output signal from the control circuit 68 energizes the Tsurenoro Dro 3 to listen to the electromagnetic on-off valve 61.

Most of the hydraulic pressure is discharged from the oil pump 37 by the lever and drained through the oil passage 60, so even though the pressure regulating valve 43 is in the state of maximizing the line pressure as described above, The line pressure is controlled by the third check valve 62.
The minimum required pressure is set as shown by the broken line in the figure.

Then, at the start of travel, the switching section 3 of the continuously variable transmission 2 is placed in the forward or reverse state. On the other hand, when the throttle opening degree is increased to 17i1 by this operation and the depression of the accelerator pedal, the electromagnetic powder clutch 1 is connected and starts transmitting power by being supplied with clutch current. Then, due to the increase in the opening degree of the solenoid valve 61, the solenoid 6
3 is de-energized and closed, the discharge pressure of the oil pump 31 is no longer drained, and as a result, the line pressure immediately returns to the high value set by the pressure regulating valve 43, and the maximum gear ratio 1 to 3 is closed.
The pulley pressing force necessary for torque transmission is exerted. and,
After this, the line pressure is regulated by the pressure regulating valve 43 as in the conventional case, and oil is supplied to the main pulley amount nervo chamber 27b by the speed change control valve 46, and continuously variable speed control is performed by converting the boolean ratio.

As is clear from the above description, according to the present invention, during idle linking, the I! ■Most of the hydraulic pressure output is drained, reducing the driving load.
Low output - The load on the L engine side is reduced, idling operation becomes stable, and there is no need to increase the throttle rating, resulting in improved fuel efficiency. Furthermore, during idling, the check valve G2 maintains a small required pressure of 1a, so that the line pressure is quickly restored at the start of running, and there is no risk of bell 1 slipping or the like. Furthermore, a drain oil passage 6
By connecting 0 to the lubrication circuit, it is possible to avoid the lubrication discipline of each part.

[Brief explanation of the drawing]

Figure 1 shows an example of a stepless insect to which the present invention is applied.
Figure 1 is a schematic diagram, Figure 2 is a circuit diagram showing an embodiment of a hydraulic control system according to the present invention, and Figure 3 is a characteristic line diagram. 1... Electromagnetic powder clutch, 2... Continuously variable transmission, 3...
...Switching section, 4...Continuously variable transmission section, 5...Final reduction section,
6...Hydraulic pressure ff1lI 011 part, 1...Crankshaft, 8...:1il, 9...Driver, eve member, 1
0...Input shaft, 11...Driven member, 11...
・Main shaft, 22...Switching clutch, 43...Subshaft, 2
4... Main pulley, 25... Sub pulley, 26... Drive bell 1~. 27.28... Hydraulic servo device, 30.
... Output shaft, 37... Oil pump, 38... Hydraulic control circuit, 39c... Line pressure circuit oil path, 43...
- Pressure adjustment valve, 44... Speed change control valve, 52... Drain circuit oil path, 61... Open/close valve, 62... Check valve. Patent applicant: Fuji Heavy Industries Co., Ltd. Agent: Patent attorney: Makoto Kobashi Ukiyo Patent attorney: Susumu Muratsuki

Claims (1)

[Claims] The line pressure, which is obtained by adjusting the discharge hydraulic pressure of the oil pump directly driven by the engine with a pressure regulating valve, is constantly supplied to the gear unit on one side of a pair of pulleys around which the drive belt is wound, and the transmission control valve In a hydraulic control device that performs continuously variable speed by supplying oil to the other servo device of the pair of boobies, a drain circuit is branched from the line pressure circuit on the outlet side of the A-il pump 11, and the drain circuit is connected to the drain circuit. A hydraulic control device for a continuously variable transmission, characterized in that the same valve is installed only during idle link and a check valve for setting line pressure to the minimum required pressure.