JPH0522101B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to a hydraulic control device for an automatic transmission that improves shock during shifting between high and low gears. [Prior Art] Generally, a hydraulic control device for an automatic transmission engages or disengages a plurality of frictional engagement devices by supplying or discharging hydraulic servo line pressure to or from a plurality of frictional engagement devices. In this way, a vehicle having a transmission mechanism that changes gears between a high gear and a low gear by selectively connecting the components of the planetary gear set to a rotating member or a fixed member in the automatic transmission case, is used while driving at high speed. When an increase in output torque is required, such as when driving on a steep slope, a driving state with a large output torque can be obtained by shifting to a low gear. [Problems to be Solved by the Invention] The vehicle with the above configuration has a large gear ratio difference between the high gear H and the low gear L (reduction ratio H:L=1:3), and has a two-stage shift between the high gear and the low gear. In the case of a transmission mechanism, when shifting from a low gear to a high gear, Fig. 10 shows a case where the drain orifice in the oil drain passage of the low gear has a small diameter, and Fig. 11 shows a case where the drain orifice has a large diameter. . (x: oil pressure of the high-speed gear hydraulic servo, y: oil pressure of the low-speed gear hydraulic servo). In Figure 10, from Tc
Since there is engagement between the high-speed gear friction engagement device and the low-speed gear friction engagement device between Td, the output shaft is fixed.
The vehicle brakes suddenly and the shifting feeling becomes worse. Furthermore, in FIG. 11, between Tc and Tb, both the high-speed friction engagement device and the low-speed friction engagement device are disengaged, resulting in an increase in engine rotation. The throttle opening is large and engine overrun may occur at high speeds. SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic control device for an automatic transmission that reduces shock during shifting between high and low gears and improves the durability of a frictional engagement device. [Means for Solving the Problems] The hydraulic control device for an automatic transmission according to the present invention includes a hydraulic pressure source 102, a pressure regulating valve 130 that adjusts the hydraulic pressure from the hydraulic source 102, and at least a high speed gear and a low gear gear. Selectable transmission mechanism 40 and the pressure regulating valve 1
When an output oil pressure of 30 is supplied, the transmission mechanism 4
High-speed stage hydraulic servo C- that sets 0 to high-speed stage
High-speed gear friction engagement device C3 operated by 3.
and a low gear friction engagement device B4 operated by a low gear hydraulic servo B-4 that sets the transmission mechanism 40 to a low gear when the output hydraulic pressure of the pressure regulating valve 130 is supplied. In the hydraulic control device 100, 400 for an automatic transmission, a switching valve that controls the supply of the output hydraulic pressure of the pressure regulating valve 130 to the high speed gear oil servo C-3 and the low gear gear hydraulic servo B-4. 440, means for controlling an increase in the oil pressure of the high-speed gear hydraulic servo C-3, means for controlling an increase in oil pressure of the low-speed gear hydraulic servo B-4, and the high-speed gear hydraulic servo A shift timing mechanism 450 is provided for promoting exhaust pressure of the low gear hydraulic servo B-4 as the hydraulic pressure of C-3 increases, and the shift timing mechanism 450
is the oil drain path 9 of the hydraulic servo B-4 next to the low speed stage.
Drain orifice 451 located near the outlet of
and the oil drain path 9 of the hydraulic servo B-4 next to the low speed stage.
a first position communicating with the drain port 474;
A valve body 472 is movable between a second position where communication between the oil drain passage 9 and the drain port 474 is cut off, and is urged to the first position by hydraulic pressure supplied from the high-speed stage side hydraulic servo C-3. The means for controlling the increase in the oil pressure of the low gear side hydraulic servo B-4 includes an oil passage that communicates the switching valve 440 and the low gear side hydraulic servo B-4. an orifice 511 provided in the hydraulic servo B between the orifice 511 and the low speed stage;
-4, the first valve is installed between the
The means for controlling the increase in the oil pressure of the high-speed side hydraulic servo C-3 includes an oil passage 6B connecting the switching valve 440 and the high-speed side hydraulic servo C-3. an orifice 459 provided therein, an accumulator control valve 460 which is a pressure regulating valve provided between the orifice 459 and the high speed side hydraulic servo C-3, and the high speed side hydraulic servo C-3. and a second accumulator 480 in communication via an orifice 452, and the accumulator control valve 460 includes:
It has a structure that controls the hydraulic pressure supplied to the high-speed stage hydraulic servo C-3 according to the hydraulic pressure accumulated in the second accumulator 480. [Operations and Effects of the Invention] With the above configuration, the hydraulic control device for an automatic transmission of the present invention has the following operations and effects. A switching valve for controlling the supply of the output hydraulic pressure of the pressure regulating valve to the high-speed side hydraulic servo and the low-speed side hydraulic servo, a means for controlling an increase in the hydraulic pressure of the high-speed side hydraulic servo, and It consists of a means for controlling the increase in the oil pressure of the hydraulic servo, and is equipped with a shift timing mechanism that accelerates the exhaust pressure of the low gear hydraulic servo as the hydraulic pressure of the high gear hydraulic servo increases. The transmission mechanism including the frictional engagement device can be simplified, and the transmission mechanism does not require a one-way clutch, so the axial dimension can be reduced. [Example] A hydraulic control device for an automatic transmission according to the present invention will be described based on an example shown in the drawings. FIG. 1 shows a four-wheel drive automatic transmission A to which the hydraulic control device of the present invention is applied, and FIG. 2 shows its gear train. 10 is a 4-speed automatic transmission with overdrive that is a main transmission; 40 is a 4-wheel drive transfer that is a sub-transmission connected to the output shaft 32 of the planetary gear transmission of the 4-speed automatic transmission 10; shows. The four-wheel drive transfer 40 is attached to the four-speed automatic transmission 10 attached to the engine E, and is connected to the first output shaft 4.
2 is connected to the rear wheel drive propeller shaft C,
The second output shaft 52 is a propeller shaft B for front wheel drive.
connected to. The 4-speed automatic transmission 10 includes a hydraulic torque converter T, an overdrive mechanism OD, and a forward speed 3.
Equipped with an underdrive mechanism UD for one stage after advancing. The torque converter T includes a pump 11 connected to the output shaft of the engine E, a turbine 13 connected to the output shaft 12 of the torque converter T, a stator 15 connected to a fixed part via a one-way clutch 14, and a direct coupling clutch. 16, and the output shaft 12 of the torque converter T serves as the input shaft of the overdrive mechanism OD. The overdrive mechanism OD includes frictional engagement elements such as a multi-disc clutch C ₀ , a multi-disc brake B ₀ and a one-way clutch F ₀ , and the selective engagement of these frictional engagement elements allows the components to be attached to a fixed member such as a transmission case. It consists of a planetary gear set P ₀ that is fixed to the input shaft, output shaft, or other components, or is released from the fixation or connection. The planetary gear set _P0 is connected to the input shaft 12.
The carrier 21 is connected to the ring gear 2, and the ring gear 2 is connected to the output shaft 25 of the overdrive mechanism OD.
2. Rotatably fitted onto the input shaft 12 and fixed to the transmission case via the brake _B0 ,
A sun gear 23 is connected to the carrier 21 via a clutch C ₀ and a one-way clutch F ₀ parallel to the clutch C ₀ , and is rotatably supported by the carrier 21 and has teeth on the sun gear 23 and ring gear 22. It consists of a planetary pinion 24 that is fitted together. The output shaft 25 of the overdrive mechanism OD also serves as the input shaft of the underdrive mechanism UD, which has three forward stages and one reverse stage. The underdrive mechanism UD includes multi-disc clutches C1 and C2, which are frictional engagement elements, a belt brake B1, multi-disc brakes B2 and B3, one-way clutches F1 and F2, a front planetary gear set P1, and a rear planetary gear. Set P2
It consists of. The front gear set P1 is the clutch C.
1, and the output shaft 3 of the underdrive mechanism UD.
2, a carrier 33 connected to the input shaft 25 via a clutch C2, a belt brake B1, a brake B2 parallel to the belt brake B1, and a one-way clutch F1 connected in series with the brake B2. A sun gear 34 is fixed to the transmission case via a sun gear 34, and a planetary pinion 35 is rotatably supported by the carrier 33 and meshed with the sun gear 34 and the ring gear 31.
It consists of. Rear planetary gear set P2 is brake B
3, a carrier 36 fixed to the transmission case via a one-way clutch F2 parallel to the brake B3, and the front planetary gear set P1.
A sun gear 37 is integrally formed with the sun gear shaft 401 together with the sun gear 34, a ring gear 38 is connected to the output shaft 32, and is rotatably supported by the carrier 36 and meshed with the sun gear 37 and the ring gear 38. It consists of a planetary pinion 39. The shift levers (not shown) of the main transmission provided at the driver's seat for driving the manual valve 210 of the main hydraulic control device 100, which will be described later, are P (parking), R (reverse), N (neutral), and D. It has a main shift position MSP of each range (drive), S (second), and L (low), and the setting range of this main shift position MSP and the 4th gear (4),
Table 1 shows the operating relationships of the clutch and brake in 3rd gear (3), 2nd gear (2), and 1st gear (1).

[Table] Main hydraulic control device 100 of 4-speed automatic transmission 10
includes an oil strainer 101, a hydraulic pump 102 which is a line oil pressure generation source, and a cooler bypass valve 11.
5. Pressure relief valve 116, release clutch control valve 117, release brake control valve 118, lock-up relay valve 12
0, pressure regulating valve (regulator valve) 130, second
Pressure adjustment valve 150, cutback valve 160, lockup control valve 170, first accumulator control valve 180, second accumulator control valve 1
90, throttle valve 200, manual valve 21
0, 1-2 shift valve 220, 2-3 shift valve 23
0, 3-4 shift valve 240, intermediate coast modulator valve 245 that adjusts the hydraulic pressure supplied to the brake B1, low coast modulator valve 250 that adjusts the hydraulic pressure supplied to the hydraulic servo B-3, clutch An accumulator 260 that smoothly engages C0, an accumulator 270 that smoothly engages brake B0, an accumulator 280 that smoothly engages clutch C2, and an accumulator 280 that smoothly engages brake B2. Accumulator 290 and clutch C0, C for smooth operation
Pressure oil supplied to hydraulic servos C-0, C-1, C-2 of 1, C2 and hydraulic servos B-0, B-1, B-2, B-3 of brakes B0, B1, B2, B3. Flow control valve 3 with check valve to control the flow rate of
01,303,304,305,306,30
7,308,309, shuttle valve 302, opened and closed by the output of the electronic control device (computer) 2-
A first solenoid valve S1 that controls the 3-shift valve 230, a second solenoid valve S that controls both the 1-2 shift valve 220 and the 3-4 shift valve 240.
2. Consists of a third solenoid valve S3 that controls both the lock-up relay valve 120 and the lock-up control valve 170, and an oil passage that communicates between each valve and the hydraulic cylinders of the clutch and brake;
ST1, ST2, ST3, and ST4 indicate oil strainers provided between each oil passage, L1 and L2 indicate lubricating oil passages, and O/C indicates an oil cooler. Hydraulic oil pumped up from a hydraulic source by a hydraulic pump 102 via an oil strainer 101 is adjusted to a predetermined oil pressure (line pressure) by a pressure regulating valve 130, and is then transferred to a line oil pressure output oil path (hereinafter abbreviated as oil path) 1.
supplied to The pressure regulating valve 130 is controlled by the pressure (throttle pressure) corresponding to the engine torque request signal generated by the throttle valve 200, and outputs the pressure (line pressure) corresponding to the torque request signal. The transfer 40 in FIG. 2 includes a clutch C3 that is a high-speed gear friction engagement device, a brake B4 that is a low gear friction engagement device, a clutch C4 that is a two-wheel/four-wheel switching friction engagement device, and a planetary clutch. The output shafts 32 of gear sets P2 and P3 are used as input shafts, a first output shaft 42 of a transfer is arranged in series with the input shaft 32, and a first output shaft 42 is arranged between the input shaft 32 and the first output shaft 42. planetary gear set
Pf, a four-wheel drive sleeve 51 rotatably fitted around the first output shaft 42; a second output installed parallel to the input shaft 32 and in the opposite direction to the first output shaft 42; shaft 52, the sleeve 51
and a second output shaft 52. The planetary gear set Pf includes a sun gear 44 spline-fitted to the end of the input shaft 32, a planetary pinion 45 that meshes with the sun gear 44, and a ring gear 4 that meshes with the planetary pinion 45.
6, and a carrier 47 that rotatably holds the planetary pinion 45 and is connected to the tip of the first output shaft 42 of the transfer shaft 40. In this embodiment, as shown in FIG. 4, the brake B4
is a multi-plate friction brake for engaging the ring gear 46 with the transfer case 48, and is composed of a cylinder 49 formed within the transfer case 48 and a piston 49P mounted within the cylinder 49. It is operated by a stage hydraulic servo B-4 (hereinafter referred to as hydraulic servo B-4). The clutch C3 is arranged on the 4-speed automatic transmission 10 side of the planetary gear set Pf, and connects and disconnects the sun gear 44 and the carrier 47, and connects the cylinder 50 connected to the carrier 47 with the cylinder 50.
A high-speed stage hydraulic servo C-3 (hereinafter referred to as hydraulic servo C-3) is composed of a piston 50P mounted inside the
3). Clutch C4 is a multi-plate friction clutch for connecting and connecting the first output shaft 42 connected to carrier 47 and sleeve 51 connected to one sprocket 56 of transmission mechanism 53 for driving second output shaft 52 of transfer 40. A hydraulic servo C-4 is a clutch, and is composed of a cylinder 58 spline-fitted to the first output shaft 42 and a piston 59P mounted within the cylinder 58.
activated by The transmission mechanism 53 is connected to the sleeve 5
1, a sprocket 55 formed on the second output shaft 52, and a chain 5 stretched between these sprockets.
Consists of 7. A parking gear 59 is provided around the outer circumferential side of the cylinder 50 of the hydraulic servo C-3, and when the shift lever of the 4-speed automatic transmission 10 is selected to the parking position, the pawl 59a moves to the parking gear 5.
9 and fixes the first output shaft 42. During normal driving, the line pressure supplied to the hydraulic control device of the automatic transmission is supplied to hydraulic servo C-3 to engage clutch C3, and hydraulic servos B-4 and C-4 are exhausted to engage brake B4 and clutch. Release C4. As a result, the sun gear 44 and carrier 47 of the planetary gear set Pf are connected, and power is transmitted from the input shaft 32 to the first output shaft 42.
The transmission is transmitted at a reduction ratio of 1 to enable two-wheel drive driving with only the rear wheels. At this time, the power from the input shaft 32 is transmitted from the carrier 47 to the first output shaft 42 via the clutch C3 without passing through the sun gear 44, planetary pinion 45, or ring gear 46, so that a load is applied to the tooth surface of each gear. This increases the life of the gear. During this two-wheel drive driving, when four-wheel drive driving becomes necessary, a shift lever 401 installed on the driver's seat etc.
When the first output shaft 4 is manually shifted and line pressure is gradually supplied to the hydraulic servo C-4 of the transfer control device 400 to smoothly engage the clutch C4, the first output shaft 4
2 and the sleeve 51 are connected, and the transmission mechanism 53,
The second output shaft 52 and the propeller shaft B (first
The power is also transmitted to the front wheels via the input shaft 32 to the first output shaft 42 and the second output shaft 52 at a reduction ratio of 1, in a four-wheel drive direct-coupled running state (high-speed four-wheel drive state). ) is obtained. During this 4-wheel drive driving, when the shift lever is manually shifted when an increase in output torque is required, such as on a steep slope, the hydraulic pressure to the hydraulic servo is changed to the inhibitor, which is a switching valve between high-speed 4-wheel drive and low-speed 4-wheel drive. The valve 440 is activated to gradually supply line pressure to the hydraulic servo B-4, and at the same time, the hydraulic servo C is activated at an appropriate timing.
-3 hydraulic pressure is discharged, the brake B4 is gradually engaged, and the clutch C3 is smoothly released. As a result, sun gear 44 and carrier 47 are released, and ring gear 46 is fixed.
The power is decelerated from the input shaft 32 via the sun gear 44, planetary pinion 45, and carrier 47, and is transmitted to the first output shaft 42 and the second output shaft 52.
A four-wheel drive deceleration driving state (low-speed four-wheel drive state) with large torque is obtained. The shift lever (not shown) of the transfer manual valve 410 provided in the driver's seat for driving the transfer manual valve 410 is H2 (directly connected to two-wheel drive),
It has a sub-shift position SSP for each range of H4 (4-wheel drive direct connection) and L4 (4-wheel drive deceleration), and the setting range of this sub-shift position SSP and brake B
4. Table 2 shows the operational relationship between the engagement and release of clutches C3 and C4 and the running state of the vehicle.

[Table] In Tables 1 and 2, ○ in S1, S2, and S4 indicates energization, and × in S1, S2, S3, and S4
Indicates de-energized. ◎ becomes a lock-up state by energizing S3. Once S4 is de-energized, α maintains the directly connected running state even if S4 is energized. Once S4 is energized, β maintains the decelerated running state even if S4 is de-energized. E indicates that the corresponding clutch or brake is engaged, and X indicates that the corresponding clutch or brake is released. The corresponding one-way clutch of L is engaged in the engine drive state, but this engagement is not necessarily required as power transmission is guaranteed by the clutch or brake built in parallel. Indicates that (lock). (L) indicates that the corresponding one-way clutch is engaged only in engine drive conditions and not in engine brake conditions. f indicates that the corresponding one-way clutch is free. The transfer control device 400, which is a sub-hydraulic control device of the four-wheel drive transfer 40, is supplied with line hydraulic pressure to the transfer control device 400 from the oil path 1 of the main hydraulic control device 100 via the manual valve 210. When the manual valve 210 is in the parking (P) position, as shown in Table 3, the transfer control device 4
00, the load on the parking mechanism is reduced by fixing only the first output shaft 42 regardless of the set position of the shift lever or shift switch of the auxiliary transmission, and Always has stable parking performance,
As shown in FIG. 5, a transfer manual valve 410 supplies the line pressure oil supplied through the oil passage 6 to the oil passages 7 and 8 by means of a shift lever provided at the driver's seat, and serves as a gear selection means. ,
Relay valve 420, inhibitor valve 440 that switches engagement between C3 and B4, accumulator 490 that smoothly engages brake B4, and brake B.
4, installed in the oil drain path 9 of the hydraulic servo B-4, L4
→H4 or L4 →H2 hydraulic servo B-4 when shifting
A shift timing mechanism 450 that relates the timing (adjustment) of the exhaust pressure of the clutch C3 to the timing of supplying the hydraulic pressure of the hydraulic servo C-3 of the clutch C3;
A shock relaxation mechanism 500 provided in the supply oil path 6A to the hydraulic servo C-3 of No. 3 to relieve the rise of the line oil pressure, the hydraulic servos B-4 and C-4 of the brake B4 and the clutch C4 are supplied. Flow control valve 51 with check valve that controls the flow rate of line pressure oil
1,512, oil strainers ST5, ST6, fourth solenoid valve S4 opened and closed by the output of electronic control device 600, oil return oil path O/R to 4-speed automatic transmission 10, and between each valve and clutch,
Consists of oil passages that connect the brake hydraulic cylinders. The shift timing mechanism 450 includes a drain orifice 4 provided in the oil drain passage 9 as shown in FIG.
51 and a shift timing valve 470. The shift timing valve 470 has a spring 4 located downward in the figure.
When the transfer 40 is changed to H2 or H4 running state,
Line pressure enters the lower end oil chamber 473 via the oil passage 6A, and the spool 472 is set upward in the figure by the action of the spring 471, allowing the drain oil passage 9 and the drain port 474 to communicate in the intermediate oil chamber 475, and the hydraulic servo B - Promote the exhaust pressure of 4. Transfer 4
When the manual valve 410 of 0 is in L4, the lower end oil chamber 4
The line pressure is exhausted from 73, and the line pressure is discharged from the upper end oil chamber 476 which is always in communication with the oil passage 6.
The spool 472 is set at the bottom in the figure. Line pressure acts on the upper end oil chamber 476 of the shift timing valve 470, whereby the shift timing valve 470
The characteristics of the engine change depending on the throttle opening. By performing this control in accordance with the line pressure, the transfer control device 400 may be provided with a new means for generating pressure in accordance with the torque request signal for the control, and the main hydraulic control device 100 may be provided with an oil that communicates the signal pressure. There is no need to arrange a path between the main hydraulic control device 100 and the transfer control device 400. The shock relief mechanism 500 includes a third accumulator control valve 460 and an accumulator 480 that smoothly engages the clutch C3. The third accumulator control valve 460 has a spool 462 with a spring 461 mounted on its back in the upper direction in the drawing. Load, oil passage 6B, intermediate oil chamber 4
63, the oil passage 6D is displaced in response to the feedback of the output oil pressure applied to the lower end oil chamber 464 via the orifice 513, regulates the line pressure supplied from the oil passage 6B, and outputs it to the oil passage 6D as output oil pressure. The oil pressure is supplied to the accumulator chamber 482 from the port 481 of the accumulator 480 to perform pressure accumulation control of the accumulator 480, and the output hydraulic pressure from the accumulator chamber 482 is fed back to the upper end land 485 via the oil path 6E. Ru. This third accumulator control valve 460
Since the diameter of the orifice 452 of the oil passage 6A of the accumulator 480 can be provided separately from the orifice 459 to the hydraulic servo C-3, the operating time of the accumulator 480 can be set relatively freely. When the accumulator 490 is changed from the H2 or H4 running state to the L4 running state, the hydraulic pressure supplied to B-4 from the oil passage 6C is applied to the accumulator chamber 493, so that the brake B4 is engaged. is performed smoothly, and the line pressure supplied from the oil passage 6 is supplied to the back pressure chamber from the back pressure port 491 to control the back pressure of the accumulator 490.
The rise control of the engagement hydraulic pressure is performed. When shifting from low gear L4 to high gear, as shown in Fig. 7, when the hydraulic pressure Y of hydraulic servo B-4 of brake B4 is equal to the line pressure, that is, when shifting from low gear L4 to high gear
In this state, the driving vehicle operates the shift lever of the transfer 40 from L4 to H4 (to point), the oil passage 6 and the oil passage 7 are communicated, and the spool 4 of the relay valve 420 is opened.
21 and the plunger 422 have a fourth solenoid valve S4 in the lower end oil chamber 423 if the change is permitted.
is in a de-energized state, solenoid pressure enters, and the oil passage 7 and the oil passage 7A are set upward in the drawing to communicate with each other, line pressure enters the lower end oil chamber 441 of the inhibitor valve 440, and the plunger 442 and spool 443
is set upward in the figure (point ta). In this respect, the oil passage 6C and the exhaust pressure oil passage 9 communicate with each other through the inhibitor valve 440, and the oil pressure of the hydraulic servo B-4 is gradually exhausted through the drain orifice 513, and the oil passage 6 and the oil passage 6B, line pressure is supplied to the intermediate oil chamber 463 of the third accumulator control valve 460, and the output oil pressure of the third accumulator control valve 460 is output to the accumulator 480, The humerator 480 starts operating (point tb). At this time, line pressure is supplied to the oil passage 6A to the lower end oil chamber 473 of the shift timing valve 470, so the spool 472 is set upward in the figure and passes through the oil drain passage 9 and the intermediate oil chamber 475 to the drain port 473.
74, the exhaust pressure is promoted and the brake B4 is released (point tc). Between (ta point) and (td) point, the hydraulic pressure of brake B4 and accumulator 490 is drained through drain orifice 513, so high pressure is maintained for a long time by reaction force elements (spring, back pressure) of accumulator. sufficient torque capacity can be obtained and fluctuations in engine speed and output shaft torque can be suppressed. A neutral state exists between (tc point) and (ta point), the engine speed decreases, and the output shaft torque is found at (tc point), then (td
point). In this way, the release of brake B4 and the engagement of clutch C3 (td point) coincide with each other, so there is no increase in engine rotation speed or sudden drop in engine rotation speed, and fluctuations in output shaft torque are small. Shift feeling improves. At (point te), the operation of the accumulator 480 is completed, and the hydraulic pressure X of the hydraulic servo C-3 becomes the same pressure as the line pressure. FIG. 9 shows another embodiment of the hydraulic control device for an automatic transmission according to the present invention. In this embodiment, the brake B4 is replaced with an accumulator that smoothly engages the brake B4.
cushion plate 5 between the piston 49P and the piston 49P.
There are 20. This cushion plate 52
0 has the same function and effect as the accumulator 480. Further, the storage plate 480 may be a cushion plate provided between the clutch C3 and the piston 50P. FIG. 10 shows still another embodiment of the hydraulic control device for an automatic transmission according to the present invention. This embodiment includes an accumulator 490 and a cushion plate 5 for smooth engagement of the brake B4.
20, a cushion plate is provided for smooth engagement when the output torque of the 4-speed automatic transmission 10, which is the main transmission, is small, and an accumulator is used for smooth engagement when the output torque is large. By setting this to occur, a smooth H4→L4 shift is possible regardless of the magnitude of the output torque of the 4-speed automatic transmission 10. Table 3 shows the communication state between oil passage 1 and oil passages 2 to 6 at the shift position of the shift lever of the main transmission. The manual valve 510 is connected to a shift lever provided on the driver's seat, and is manually operated to switch between P (parking) and R according to the range of the shift lever.
(Reverse), N (Neutral), D (Drive),
Move to the S (second) and L (low) positions.
Table 3 shows the communication state between oil passage 1 and oil passages 2 to 6 in the shift range of each shift lever. ○ indicates the case where line pressure is supplied through communication, and x indicates the case where the line pressure is exhausted.

[Table] Table 4 shows the communication state between the oil passage 6 and the oil passages 7 and 8 at the shift position of the sub-transmission.

[Table] In Tables 3 and 4, ◯ indicates the case where line pressure is supplied through communication, and × indicates the case where the line pressure is exhausted. The electronic control device 600, which controls the energization of the solenoid valves S1 to S4 of the hydraulic control device 100 and the transfer control device 400, detects the main transmission shift lever position as shown in FIG. A sensor 610, a transfer shift lever position sensor 620 that detects the position of the setting range of the sub-transmission, and a vehicle speed sensor 6 that converts a signal detected from the output shaft rotational speed of the sub-transmission into vehicle speed.
30, a throttle opening sensor 640 that detects the amount of accelerator, a rotation speed detection sensor 650 that is a rotation speed detection means that detects the rotation speed of the output shaft 32 of the 4-speed automatic transmission, which is the input shaft of the transfer 40; The I/O port 660, which is an input port and an output port to the solenoid valves S1 to S4, the central processing unit CPU, the random access memory RAM that performs shift point processing, and the shift pattern data to the shift point and lock-up point. Consists of read-only memory ROM that stores data.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a four-wheel drive vehicle, Figure 2 is a skeleton diagram of Figure 1, Figure 3 is a hydraulic circuit diagram of a 4-speed automatic transmission, and Figure 4 is a sub-shift of a 4-speed automatic transmission. 5 is a hydraulic circuit diagram of an auxiliary transmission of a 4-speed automatic transmission that employs the hydraulic circuit inhibitor valve of the present invention, FIG. 6 is a schematic diagram of FIG. 5, and FIG. 7 is a diagram of the main transmission. Figure 8 is a graph showing the servo reaction characteristics, engine output wheel characteristics, and output shaft torque characteristics during an L→H shift in the hydraulic control device of the automatic transmission of the invention, which was adopted in a four-wheel drive dynamic transmission. A block diagram of an electronic control device, FIG. 9 is a hydraulic circuit diagram showing another embodiment of the hydraulic control device for an automatic transmission of the present invention, and FIG. 10 is a hydraulic circuit diagram showing another embodiment of the hydraulic control device for an automatic transmission of the present invention. Hydraulic circuit diagrams showing examples, Figures 11 and 12 are conventional L
→This is a graph showing servo pressure characteristics, engine output shaft characteristics, and output shaft torque characteristics during H shift. In the figure, A...4-wheel drive automatic transmission, 1...Line hydraulic output oil path, 10...Main transmission (4-speed automatic transmission), 40...4-wheel drive transfer, 1
00... Main hydraulic control device, 400... Sub-hydraulic control device (transfer hydraulic control device).

Claims (1)

[Claims] 1. A hydraulic source, a pressure regulating valve that adjusts the hydraulic pressure from the hydraulic source, a transmission mechanism that can select at least a high speed gear and a low gear gear, and when the output hydraulic pressure of the pressure regulating valve is supplied. , a high-speed gear friction engagement device operated by a high-speed gear hydraulic servo that sets the transmission mechanism to a high gear; and when the output hydraulic pressure of the pressure regulating valve is supplied, sets the transmission mechanism to a low gear. A hydraulic control device for an automatic transmission comprising a low gear friction engagement device operated by a low gear gear hydraulic servo that adjusts the pressure to the high gear gear hydraulic servo and the low gear gear hydraulic servo. a switching valve that controls the supply of the output hydraulic pressure of the valve; a means for controlling an increase in the hydraulic pressure of the high-speed gear hydraulic servo; a means for controlling an increase in the hydraulic pressure of the low-speed gear hydraulic servo; and the high-speed gear hydraulic servo. A shift timing mechanism is provided that accelerates the discharge pressure of the lower gear hydraulic servo as the oil pressure of the lower gear hydraulic servo increases, and the shift timing mechanism is arranged near the outlet of the drainage path of the lower gear hydraulic servo. A drain orifice arranged in the lower speed stage hydraulic servo is movable between a first position where the oil drain passage of the low speed stage side hydraulic servo is communicated with the drain port, and a second position where communication between the oil drain passage and the drain port is cut off. and a shift timing valve having a valve body biased to a first position by the hydraulic pressure supplied to the high-speed gear hydraulic servo, and the means for controlling the increase in the oil pressure of the low-speed gear hydraulic servo, an orifice provided in an oil passage connecting the switching valve and the low-speed gear side hydraulic servo; and a first storage space provided between the orifice and the low-speed gear side hydraulic servo to accumulate supply hydraulic pressure. The means for controlling the rise in the hydraulic pressure of the high-speed stage hydraulic servo includes an orifice provided in an oil passage connecting the switching valve and the high-speed stage hydraulic servo; an accumulator control valve that is a pressure regulating valve provided between the high-speed stage hydraulic servo and a second accumulator that communicates with the high-speed stage hydraulic servo via an orifice; A hydraulic control device for an automatic transmission, wherein the control valve controls the hydraulic pressure supplied to the high-speed gear hydraulic servo according to the hydraulic pressure accumulated in the second accumulator. 2. The hydraulic control device for an automatic transmission according to claim 1, wherein the low gear friction engagement device includes a cushion plate.