JPH0474577B2 - - Google Patents

Description

[Detailed description of the invention]

(1) Technical Field The present invention relates to an automatic transmission, and more particularly to a low clutch which is hydraulically operated at a plurality of low speeds below a certain speed and whose input torque ratio is smaller in the certain speed than in other low speeds; The present invention relates to a device for reducing shift shock during a downshift to a certain speed in an automatic transmission including a high clutch operated at a plurality of high speed speeds higher than a certain speed. (2) Prior Art As the above-mentioned type of automatic transmission, the applicant of the present application has previously proposed the one shown in FIG. FIG. 1 shows a schematic diagram of the power transmission mechanism of the automatic transmission, and this power transmission mechanism consists of a torque converter T/
An input shaft I transmits the rotational force from the engine output shaft E through C, an output shaft O transmits the driving force to the final drive device, a first planetary gear set G1, and a second planetary gear set G1.
It has a planetary gear set G2, a first clutch C1, a second clutch (high clutch) C2, a third clutch (low clutch) C3, a first brake B1, a second brake B2, and a one-way clutch OWC. The first planetary gear set G1 is composed of a sun gear S1, an internal gear R1, and a carrier PC1 that supports a pinion gear P1 that meshes with both gears S1 and R1 at the same time. , Internal Gear R2
and a carrier PC2 that supports a pinion gear P2 that meshes with both gears S2 and R2 at the same time. Carrier PC1 can be connected to input shaft I via clutch C2, and sun gear S
1 can be connected to an input shaft I via a clutch C1. Carrier PC1 can also be connected to internal gear R2 via clutch C3. Sun gear S2 is always connected to input shaft I, and internal gear R1 and carrier PC2 are always connected to output shaft O. Brake B1 can fix carrier PC1, and brake B2 can fix sun gear S1. One-way clutch OWC is carrier
Normal rotation of PC1 (rotation in the same direction as the engine output shaft E)
It has a structure that allows rotation, but does not allow reverse rotation (rotation in the opposite direction to forward rotation) (that is, a structure that acts as a brake only during reverse rotation). The above power transmission mechanism includes clutches C1, C2 and C3, and brake B1 (one-way clutch OWC).
and B2 in various combinations, each element (S1,
S2, R1, R2, PC1, and PC2) can be changed, thereby making it possible to variously change the rotational speed of the output shaft O relative to the rotational speed of the input shaft. By operating the clutches C1, C2 and C3 and the brakes B1 and B2 in combination as shown in the table below, four forward speeds and one reverse speed can be obtained.

[Table] In the above table, the ○ mark indicates the clutch and brake that are in operation, and α ₁ and α ₂ are the sun gear S1 relative to the number of teeth of internal gears R1 and R2, respectively.
and S2, and the gear ratio is the ratio of the rotation speed of the input shaft I to the rotation speed of the output shaft O. Further, the display (OWC) below B1 indicates that the first speed can be obtained by the one-way clutch OWC even when the brake B1 is not operated. However, in the first speed in this case, it is not possible to drive from the output shaft O side.
(i.e. engine braking does not work). By the way, in such an automatic transmission, the first speed,
Considering the input torque ratio of the low clutch C3 that is activated when 2nd and 3rd gears are selected (3rd gear corresponds to the above-mentioned certain gear stage), this is the ratio between 1st gear, 2nd gear, and
In the third speed selected state, the results are as shown in the following table, and the example of the input torque ratio in this table is shown for the case where the tooth number ratio α ₂ is set to 0.45, which is the same as in Table 1 above.

[Table] As is clear from this table, the input torque ratio of low clutch C3 is 1st and 2nd when 3rd gear is selected.
Therefore, the required clutch capacity of the low clutch C3 in the third speed selection state is approximately one third of that in the first and second speed selection states. On the other hand, the friction elements of the automatic transmission (clutch C1,
C2, C3 and brakes B1, B2) are hydraulically operated, and the operating hydraulic pressure is the standard pressure of the automatic transmission, that is, the line pressure P _L that changes depending on the throttle opening as shown by the solid line in FIG. However, if the low clutch C3 is operated by the same oil pressure P _L when selecting 1st, 2nd, and 3rd speeds,
The clutch capacity of the clutch C3 is the same for each gear, and the clutch capacity of the low clutch C3 becomes excessive in the third gear selection state. Therefore, as shown in Table 1 above, the fourth
When downshifting from the speed selection state to the third speed selection state in which the low clutch is actuated, the low clutch C3 causes a large shift shock due to the excessive clutch capacity. In order to solve this problem, it may be possible to install an accumulator that gradually increases the hydraulic pressure of the low clutch C3.
Since the clutch capacity of the automatic transmission is approximately three times the required clutch capacity when the third gear is selected, an extremely large accumulator is required, making the automatic transmission whose mission is to be compact, large and impractical. (3) Purpose of the Invention The present invention provides a method for controlling the working hydraulic pressure of a low clutch that is hydraulically operated in a plurality of lower gears (first, second, third) below a certain gear (third gear). If the pressure is reduced to match the required clutch capacity only when selecting a gear, the shift shock when downshifting to a certain gear (shifting from 4th gear to 3rd gear) can be reduced, and the above-mentioned problem can be solved. From the perspective of obtaining
It is an object of the present invention to provide a shift shock reduction device for an automatic transmission that embodies this idea. (4) Structure of the Invention For this purpose, the device of the present invention, in the automatic transmission of the above type, generates output pressure when the high clutch is not activated in response to activation or deactivation of the high clutch, and dissipates the output pressure when activated. A high clutch operation identification valve; and a low clutch pressure reducing valve that reduces the hydraulic pressure toward the low clutch while the output pressure of the high clutch operation identification valve disappears, and stops this pressure reducing action while the output pressure is generated. It is characterized by (5) Examples Hereinafter, the present invention will be explained in detail with reference to illustrated examples. FIG. 2 shows the device of the present invention incorporated into a hydraulic circuit for controlling the speed change of the power transmission mechanism shown in FIG. 1, and this hydraulic circuit includes a regulator valve 2, a manual valve 4, a throttle valve 6, Throttle fail safe valve 8, throttle modulator valve 10, pressure modifier valve 12, cutback valve 14, line pressure booster valve 16, governor valve 18, 1-2 shift valve 20, 2-3 shift valve 22 , 3-4
Shift valve 24, 2-4 timing valve 2
6, 2-3 timing valve 28, 3-4 timing valve 30, 3-2 timing valve 32,
1st speed fixed range pressure reducing valve 34, torque converter pressure reducing valve 36, 1-2 accumulator 38,
The device of the present invention has a 4-3 accumulator 40 and an overdrive inhibitor solenoid 42, and further includes a low clutch pressure reducing valve 801 and a third speed identification valve (high clutch operation identification valve) 802,
These valves are connected to each other as shown in FIG. 2, and also to the oil pump O/P, torque converter T/C, clutches C1, C2, C3, and brakes B1 and B2 as shown. The brake B2 is divided into a servo brake chamber S/A, which is a hydraulic chamber for engaging the brake, and a servo release chamber S/A, which is a hydraulic chamber for releasing the brake.
R (The pressure receiving area of the servo release chamber S/R is larger than the pressure receiving area of the servo brining chamber S/A, so when hydraulic pressure is supplied to the servo release chamber S/R, the hydraulic pressure is applied to the servo blazing chamber S/A. Brake B2 is released even if B2 is supplied.) Overdrive inhibitor solenoid 42 is electrically connected to overdrive inhibitor switch SW. Next, the structure and operation of each valve will be explained. The regulator valve 2 has ports 102a to 1
02i and the valve hole 10
The spool 202 has lands 202a to 202d corresponding to the ports 252a and 2 and is fitted into the valve hole 102 so as to be movable in the axial direction.
52b and fixed within the valve hole 102; a spool 203 having lands 203a and 203b corresponding to the inner diameter of the sleeve 252 and fitted into the inner diameter of the sleeve 252 so as to be movable in the axial direction; Spring seat 254 arranged at the upper end of sleeve 252 in the figure, spring seat 245 and land 2 of spool 202
03d and a spring 302 provided between the two. Land 202 of spool 202
b, 202c and 202d have the same diameter, and the diameter of land 202a is smaller than the diameter of these lands. The land 254a of the spool 203 has a larger diameter than the land 254b. port 102
a, 102c and 102g are drain ports. The ports 102b and 102e are connected to an oil passage 402 (line pressure circuit) through which pressure oil is discharged from the oil pump O/P. An orifice 606 is provided at the entrance of the port 102b. The port 102 is connected to the oil pump O/P via the oil passage 404.
It is connected to the variable capacity oil chamber C/C. The oil pump O/P is a variable displacement vane pump, and is configured to reduce the discharge amount according to the oil pressure supplied to the oil chamber C/C. Port 102f is connected to port 136b of torque converter pressure reducing valve 36 via oil passage 406. In addition,
An orifice 608 is provided in the oil passage 406.
The port 102h is connected to the ports 114c and 114g of the cut valve 14 via an oil passage 410, and the port 102i is connected to the ports 114a and 114d of the cutback valve 14 and the pressure modifier valve 12 via an oil passage 411. ports 112c and 112e. The regulator valve 2 is connected to the oil passage 4 as follows.
Adjust the line pressure of 02. The port 10 is located at the difference in area between the lands 202a and 202b of the spool 202.
Hydraulic pressure acts from 2b and applies a downward force to the spool 202 in the figure. On the other hand, an upward force in the figure from a spring 302 and an upward force from a spool 203 (described later) are acting on the spool 202. The oil pressure in the port 102b is adjusted so as to balance the upward force by discharging the oil in the port 102e, which communicates with the port 102e through the oil passage 402, to the port 102f. That is, when the hydraulic pressure of the port 102b becomes high and the downward force becomes larger than the upward force, the spool 2
02 moves slightly downward, a gap is formed between the land 202d and the port 102f, and the oil in the port 102e flows out from this gap, and the oil in the port 102e flows out.
The oil pressure at port 02e decreases, but since port 102e communicates with port 102b through oil passage 402, the oil pressure at port 102b eventually decreases, and the downward force becomes smaller, so spool 202 is pushed back upward. . By continuously repeating such operations, the oil pressure of the port 102b, that is, the oil pressure of the oil passage 402, is regulated so as to always balance the upward force. The oil pressure (ie, line pressure) obtained in this manner changes in accordance with the upward force exerted by the spool 203, since the force exerted by the spring 302 is constant. Since the positions of the ports 102h and 102i of the valve hole 102 correspond to the positions of the ports 252a and 252b of the sleeve 252, respectively, the oil pressure of the oil passage 410 acts on the difference in area between the lands 203a and 203b of the spool 203. , also Land 203
The oil pressure of the oil passage 411 acts on the lower end of the spool 203, and the spool 203 receives an upward force. Therefore,
Line pressure is controlled according to the oil pressure in oil passages 410 and 411. The specific characteristics of the line pressure will be explained after other related valves are explained. The manual valve 4 has ports 104a to 10
A valve hole 104 having a diameter of 4f and a valve hole 104
The spool 204 has lands 204a and 204b corresponding to the spool 204 and is fitted into the valve hole 104 so as to be movable in the axial direction. The spool 204 is operated by a shift lever on the driver's seat (not shown), and is positioned in six positions: parking position P, reverse travel position R, neutral position N, forward automatic shift travel position D, 2nd gear position, and 1st gear position. It is set to stop at . port 104
a is a drain port, and the port 104b is connected to the clutch C1 and the port 502a of the shuttle valve 502 via an oil passage 408.
The port 104c is connected to the oil passage 402 which is the line pressure circuit described above, and the port 104d is connected to the oil passage 412.
via 1-2 shift valve 20 port 120
g, connected to the port 124h of the 3-4 shift valve 24 and the governor valve 18, and the port 104e
is connected to the line pressure booster valve 1 via the oil passage 414.
6 port 116e, 2-3 shift valve 22 port 122a, and shuttle valve 504 port 504a, and port 104f is connected to 1st speed fixed range pressure reducing valve 34 via oil passage 416.
It is connected to port 134d of. Spool 2
04 stops at each stop position, the port 104c to which line pressure is supplied communicates with each port as shown in the table below, and the line pressure is distributed to each port.

[Table] Note that line pressure is supplied to the ports marked with a circle in the above table, and all other ports are connected to the drain port. The throttle valve 6 has a valve hole 106 having ports 106a to 106f, and lands 206a to 206c corresponding to the valve hole 106, and a spool 2 fitted into the valve hole 106 so as to be movable in the axial direction.
06, a spring 306 that presses the spool 206 to the left in the figure, a plunger 207 that can move within the valve hole 106 in conjunction with an accelerator pedal (not shown) and a linkage, etc.;
07 and a spring 307 provided between the spool 206 and the spool 206. Land 206c has a smaller diameter than lands 206a and 206b. Ports 106a and 106f are drain ports. The port 106b is connected to an oil passage 418 which is a kick-down pressure circuit, and as described later, kick-down pressure (pressure equivalent to line pressure) is supplied only when the accelerator pedal is depressed to the kick-down position, and otherwise. is connected to the drain port 106a. port 10
6c and 106e are connected to an oil passage 420 which is a throttle pressure circuit, and port 106d is connected to an oil passage 402 which is a line pressure circuit. Note that an orifice 610 is provided at the entrance of the port 106e. In the throttle valve 6 having such a configuration, the force exerted by the spring 306 and the force of the hydraulic pressure of the port 106e acting on the area difference between the lands 206b and 206c, which is directed to the left in the figure, and the force directed to the right by the spring 307 are balanced. As such, the line pressure of the port 106d is used as a hydraulic pressure source, and the hydraulic pressure of the ports 106e and 106c is regulated by a well-known pressure regulating action. Therefore, the oil passage 420
, a hydraulic pressure proportional to the pressure of the spring 307 is obtained, but since the pressure of the spring 307 is variable by the plunger 207 that is linked to the accelerator pedal, the amount of depression of the hydraulic accelerator pedal in the oil passage 420 (throttle opening) is variable. The oil pressure (i.e., throttle pressure) becomes proportional to the In addition,
During kickdown, throttle valve 6
is pushed to the right side in the figure by plunger 207 and spring 307, loses its pressure regulating function, and oil passage 4
Since the line pressure is also supplied to the drain port 20, the line pressure is also supplied to the port 106b, which is a drain port, as will be described later. The throttle fuel safety valve 8 has a valve hole 108 having ports 108a-e (this valve hole 108 is connected to the valve hole 10 of the throttle valve 6).
6) and the land 208a
- c and is fitted into the valve hole 108 so as to be movable in the axial direction, and the land 207
The aforementioned plunger 207 (land 20
7a is fit into the inner diameter part of the sleeve 208 so as to be freely movable in the axial direction), and a plug 209 that seals the valve hole 108 (however, the plunger 207
) and a plug 2
09 and a spring 308 provided between the sleeve 208 and the sleeve 208. Ports 108a and 108d of the valve hole 108 are connected to an oil passage 420, which is the aforementioned throttle pressure circuit, and port 108b is connected to an oil passage 402, which is a line pressure circuit. Port 108c is connected to port 506a of shuttle valve 506 via oil passage 402. Further, the port 108e is connected to the oil passage 418, which is the aforementioned kickdown circuit. The throttle fail-safe valve 8 having such a configuration normally has the function of reducing the pressure on the plunger 207 (that is, except during kickdown and when the accelerator linkage fails). That is, the throttle pressure supplied to the port 108a reaches the inner diameter of the sleeve 208 and the plunger 20
7 and applies a force in the right direction in the figure. Therefore, the force of the plunger 207 to compress the spring 307 (that is, the force of pressing the accelerator pedal) is reduced. The more the spring 307 is compressed, the greater the reaction force becomes, and the throttle pressure also increases as described above, so that the throttle pressure is increased by the plunger 207.
The force with which you press the accelerator pedal also increases, allowing you to maintain a nearly constant pressure on the accelerator pedal at all times. During kickdown, the plunger 207 is pushed to the position shown in the upper half of the figure, thereby opening the port 108.
e communicates with the port 108a through the inner diameter of the sleeve 208. Therefore, the oil pressure in the oil passage 420 is sent to the oil passage 418. The oil passage 420 is a throttle pressure circuit, and normally throttle pressure is supplied thereto, but during kickdown, the spool 206 of the throttle valve 6 mentioned above is also pushed in as shown in the upper half of the figure, and the ports 106d and 106c are connected to the oil passage 420. are in communication, and line pressure is also sent to the oil passage 420. Therefore, line pressure is also supplied to the oil passage 418. Since the sleeve 208 is pushed into the deep right side in the figure by the spring 308 (the upper half position in the figure), the ports 108c and 108d are
The lands 208a and 208b of the sleeve 208 communicate with each other, and the throttle pressure of the oil passage 420 is sent to the oil passage 422. However, if a failure occurs in the linkage connecting the accelerator pedal and the plunger 207 and the plunger 207 is pushed back to the left in the figure, the sleeve 208 also moves to the left together with the plunger 207, resulting in the state shown in the lower half of the figure. becomes. Therefore, the port 108c communicates with the port 108b, and the oil passage 422 is connected to the oil passage 402.
Line pressure is fed from the line pressure, and as described below, the line pressure reaches its highest state, so there is no slippage in the clutch or brake, and the car can be driven as necessary despite the above-mentioned failure. can. (For example, when driving the vehicle to a repair shop by itself.) The throttle modulator valve 10 has a valve hole 110 having ports 110a to 110e, and a spool 210 that has lands 210a to 210c corresponding to the valve hole 110 and is fitted into the valve hole 110 so as to be movable in the axial direction. and a spring 810 that presses the spool 210 to the left in the figure. Land 210a is connected to lands 210b and 2
It has a larger diameter than 10c. Ports 110a and 110d are connected to oil passage 420, which is the aforementioned throttle pressure circuit, and port 110b is connected to oil passage 418, which is the aforementioned kickdown pressure circuit. Furthermore, the ports 110c and 110e are connected to the port 122d of the 2-3 shift valve 22 via an oil passage 424. Port 110e
An orifice 612 is provided at the entrance.
In the throttle modulator valve 10 having such a configuration, the port 110b serves as a drain port via the oil passage 418 in the non-kickdown state, so the port 110d serves as a high pressure side port (throttle pressure is supplied ), and the port 110b is used as a drain port to perform pressure regulation. The balance of the spool 210 is determined by adjusting the oil pressure (throttle pressure) of the port 110a to the land 21.
Spring 3
This is accomplished by applying a force of 10 to the left. Therefore, the oil pressure of the port 110e (hereinafter referred to as "throttle modulate pressure") changes in accordance with the throttle pressure, and has a characteristic that it maintains a value lower than this by a certain value. This throttle modulate pressure is controlled by the oil passage 424 as described above.
3 shift valve 22 and used to control its switching. During kickdown, the kickdown pressure (line pressure) is supplied to the port 110b, which used to be the drain port, and the throttle modulator valve 10 loses its pressure regulating function and enters the state shown in the upper half of the figure. will be supplied with line pressure. The pressure modifier valve 12 has a valve hole 112 having ports 112a to 112e, and lands 212a and b of equal diameter corresponding to the valve hole 112, and is fitted into the valve hole 112 so as to be freely movable in the axial direction. spool 212 and spool 2
12 downward in the figure. Ports 112a and 112b are both drain ports. The ports 112c and 112e are connected to the port 102i of the regulator valve 2 via the oil passage 411 described above,
Further, the port 112d is connected to a port 506c of the shuttle valve 506 via an oil passage 426. An orifice 622 is installed at the entrance of port 112e.
is provided. In the pressure modifier valve 12 having such a configuration, the port 112d is a high pressure side port (to which throttle pressure or line pressure is supplied as described later), and the port 112d is a high pressure side port (throttle pressure or line pressure is supplied as described later).
2b is used as a drain port to perform pressure regulation.
For balancing the spool 212, the port 112e
This hydraulic pressure is achieved by the upward force in the figure acting on the land 212b and the downward force by the spring 312. Therefore, the oil pressure of port 112e (hereinafter referred to as "pressure modifier pressure")
is a constant value corresponding to the force of the spring 312. However, if the hydraulic pressure supplied to the port 112d is smaller than the force exerted by the spring 312, the pressure modifier valve 12 will not be in the pressure regulating state and will remain in the state shown in the right half of the figure. The oil pressure of 112d goes directly to the oil passage 411.
The oil pressure in the oil passage 411 becomes the same as the oil pressure in the oil passage 426. In normal cases (if the accelerator pedal linkage is not faulty and if manual valve 4 is not in position), port 1
12d is the throttle fuel safety valve 8.
Since the throttle pressure is supplied through the port 108c, the oil passage 422, the shuttle valve 506, and the oil passage 426, the pressure modifier pressure gradually increases up to a certain throttle opening and then maintains a constant value. becomes. If the accelerator pedal linkage fails, the throttle fail-safe valve 8 switches as described above and line pressure is supplied to the oil passage 422, so that the pressure modifier pressure becomes the constant pressure. In addition, when the manual valve 4 is switched from the D position to the D position as described later, the line pressure booster valve 16 is connected to the port 5 of the shuttle valve 506 via the oil passage 428.
Since line pressure is supplied to 06b, oil passage 422
Port 112d regardless of the throttle pressure value of
The line pressure is supplied to the pressure modifier, and the pressure modifier pressure remains at the above-mentioned constant pressure in this case as well. Since the pressure modifier pressure is led to the port 102i of the regulator valve 2 via the oil passage 411, the line pressure increases in accordance with the pressure modifier pressure. The pressure modifier pressure is also led to a cutback valve 14. The cutback valve 14 has ports 114a to 114a.
g and the land 214a~
a spool 214 having a diameter of 1.c and fitted in the valve hole 114 so as to be freely movable in the axial direction, and the port 114.
Port 256 corresponding to f and 114g respectively
a and 256b and fitted into the valve hole 114; and lands 215a and b.
and a spool 215 fitted to the inner diameter portion of the sleeve 256 so as to be freely movable in the axial direction. Land 214a of spool 214 has a smaller diameter than lands 214b and 214c. Also, the land 215a of the spool 215 is the land 2
It has a larger diameter than 15b. The ports 114a and 114d are connected to the oil passage 411 and supplied with the pressure modifier pressure described above.
Port 114b is a drain port. Port 114c and port 114g are connected to oil passage 410, port 114e is connected to oil passage 428, and port 114f is connected to oil passage 430, which is a governor pressure circuit. Note that an orifice 614 is provided at the entrance of the port 114g. Cutback valve 14 having such a configuration
In this case, when the manual valve 4 is not in the position or when the line pressure booster valve 16 is in the upper half position in the figure (i.e., when the oil passage 428 is a drain oil passage), the port 114d is connected to the high pressure port. At the same time, the port 114b is used as a drain port to perform pressure regulation. The spools 214 and 215 act together like a single spool, and the rightward force exerted by the pressure modifier pressure of the port 114a on the land 214a is the force exerted by the hydraulic pressure of the port 114g on the land 215b. The oil pressure (governor pressure) in port 114f balances the leftward force acting on the area difference between lands 215a and 215b. Therefore, when the governor pressure increases, the oil pressure at the port 114g (hereinafter referred to as "cutback pressure") decreases, and when the governor pressure exceeds a certain value, the state shown in the lower half of the figure occurs, and the cutback pressure decreases. It becomes 0. Also, the cutback pressure decreases as the pressure modifier pressure decreases. Cutback pressure is oil line 4
Port 10 of regulator valve 2 via 10
2h, the line pressure decreases as the governor pressure increases and as the pressure modifier pressure decreases. When the manual valve 4 is switched from the D position to the D position, line pressure is supplied to the oil passage 428 as described above, so the line pressure acts on the port 114e, and the spool 214 is pushed to the left in the figure. Therefore,
Port 114c is the drain port port 1
14b, and the oil pressure of the oil passage 410 is 0 regardless of the governor pressure and pressure modifier pressure.
become. Line pressure booster valve 16 is connected to port 116
Valve hole 116 having a to f, and valve hole 11
It consists of a spool 216 which has lands 216a to 6c corresponding to the numbers 6 and is fitted into the valve hole 116 so as to be freely movable in the axial direction, and a spring 316 which presses the spool 216 to the left in the figure. The lands 216a to 216c of the spool 216 have the same diameter, and the spool 216 is provided with a hole 216d that communicates the space between the lands 216a and 216b with the left end of the spool 216.
Ports 116c and 116f are drain ports, port 116d is connected to oil passage 428 described above, and port 116e is connected to oil passage 414. The port 116b is connected to the port 120h of the 1-2 shift valve 20 via the oil passage 432.
As will be described later, line pressure is supplied to this port 120h when the 1-2 shift valve 20 is in the speed position (up side). The port 116a is connected to the port 122g of the 2-3 shift valve 2 via the oil passage 434,
As will be described later, line pressure is supplied to this port 122g when the 2-3 shift valve 22 is in the 3rd speed position (up side). The line pressure booster valve with such a configuration is a 2-3 shift valve 22.
The behavior is different when switching from the 2nd speed position (down side) to the 3rd speed position and when switching from the 3rd speed position to the 2nd speed position. That is, 1-2
When the shift valve 20 is in the 1st gear position or when it is switched up to the 2nd gear position, the spool 216 of the line pressure booster valve 16 is pressed by the spring 316 and moves to the upper half in the figure. (When the 1-2 shift valve 20 is in the 2nd speed position, line pressure is supplied to the port 116b.
6b, so the line pressure booster valve 16 is not switched). In this state, port 116d is connected to drain port 116c.
It communicates with Next, the 2-3 shift valve 22
When the is switched to the 3rd speed position, the oil passage 43
Line pressure is supplied to 4. The line pressure of the oil passage 434 is applied to the port 116a and the hole 21 of the spool 216.
acts on the left end surface of the spool 216 through 6d,
The spool 216 is moved to the right in the figure against the force of the spring 316, so that it is in the lower half state in the figure. In this state, the port 116b and the hole 216d of the spool 216 communicate with each other (the port 116b
a is closed by land 216a), and the pressure of oil passage 432 acts on the left end of spool 216. Therefore, even when the 2-3 shift valve 22 is switched to the 2nd speed position, the line pressure booster valve 16 is maintained at the lower half position in the figure. Even if the line pressure booster valve 16 is in the lower half of the figure, if the manual valve 4 is not in the
Since the port 104e of the manual valve 4 serves as a drain port, oil is drained from the oil passage 428 to the port 104e via the port 116d, the port 116e, and the oil passage 414. However, if the manual valve 4 is in the reverse position,
Because line pressure is supplied to oil passage 415, port 1
Line pressure is supplied to the oil passage 428 via 16e and 116d. The line pressure of the oil passage 428 is supplied to the port 112d of the pressure modifier valve 12 via the shift valve 506, and acts to increase the line pressure as described above. Therefore,
When driving in 3rd gear, when switching the manual valve 4 to the 2nd or 3rd gear positions to forcefully switch to 2nd gear and use engine braking, the line pressure increases, so it is difficult to shift gears quickly and use engine braking effectively. can. Note that when the 1-2 shift valve 20 reaches the 1st speed position, the oil pressure in the oil passage 432 is discharged, so the line pressure booster valve 16 returns to the state shown in the upper half of the figure, and no longer has the effect of increasing the line pressure. The governor valve 18 is mounted so as to rotate together with the output shaft O of the automatic transmission, and is supplied with line pressure supplied from the oil passage 412 (supplied when the manual valve 4 is in the D or position). Line pressure) is used to adjust the pressure, and the oil line 430
supplies hydraulic pressure (governor pressure) corresponding to the vehicle speed. The 1-2 shift valve 20 has ports 120a to 120a.
It consists of a valve hole 120 having a diameter k, two spools 220 and 221 fitted in the valve hole 120 so as to be freely movable in the axial direction, and a spring 320 that presses the spool 220 downward in the figure. The spool 220 has lands 220a to 220c with diameters increasing in order, and the spool 221 has lands 221a to d (lands 221a to 221d).
c is the same diameter, land 221d is larger diameter than these)
have. Ports 120a, 120f and 1
20i is a drain port. port 120b
is connected to oil passage 418 which is a kickdown pressure circuit, and the oil pressure of port 120b is connected to spool 2.
When spool 20 is on the down side (right half in the figure), it affects the area difference between lands 220a and 220b, and when spool 220 is on the up side (left half in the figure), it affects the area between lands 220a and 220c. The spool 220 is pushed downward in the figure by acting on the difference. The port 120c is connected to an oil passage 420 which is a throttle pressure circuit.
When the spool 220 is on the down side, the oil pressure c acts on the area difference between the lands 220b and 220c and pushes the spool 220 downward, but when the spool 220 is on the up side, the oil pressure on the land 220c
It is designed so that it only acts around the periphery and does not generate any downward pushing force. Ports 120j and 120k
is connected to an oil passage 430 which is a governor pressure circuit, and when the spool 221 is in the down position, the land 221d and c are connected from the area of the land 221d.
(i.e. land 22
1c), and when the spool 221 is in the up position, the land 2
The governor pressure acts on the area of 21d, and the spool 22
1 is pushed upwards. The port 120g connected to the oil passage 412 is cut off by the land 221b when the spool 221 is in the down position, and communicates with the oil passage 432 via the port 120h when the spool 221 is in the up position. There is. The oil passage 432 is connected to the servo brining chamber S/A of the brake B2. The port 120d is connected to the shuttle valve 5 via an oil passage 436.
02 port 502c. The port 120d communicates with the port 120e when the spool 221 is in the down position. Port 120e is connected to brake B1 via oil passage 438. 1- of such a configuration
The 2-shift valve 20 controls the supply of pressure oil to the servo brining chamber S/A and the brake B1 according to its down position and up position, the details of which will be described later. The 2-3 shift valve 22 has ports 122a to 122a.
The valve hole 122 having the j and the lands 222a~
A spool 222 having a diameter e and fitted in the valve hole 122 so as to be movable in the axial direction;
2, and a spring 322 disposed between the spool 222 and the plug 223. The diameters of the lands 222a to 222c increase in order, the lands 222c and 222d have the same diameter, and the land 222e has an even larger diameter. Ports 122b and 122h are drain ports. Port 122a is oil passage 414
(an oil passage to which line pressure is supplied when the manual valve 4 is in the or position), and the oil pressure of the port 112a is configured to act on the upper end surface of the plug 223. The port 122c is connected to an oil passage 418 which is a kickdown pressure circuit, and the oil pressure of the port 122c is connected to the spool 222.
A downward force is applied to the spool 222 by acting on the area difference between the lands 222a and 222b. Throttle modulate pressure is supplied to the port 123d from the oil passage 424,
When the spool 222 is in the up position, the throttle modulate pressure acts on the area difference between the lands 222b and 222c to apply a downward force. Throttle pressure is supplied to the port 122e from the oil passage 420, and the spool 222
is in the down position, lands 222b and 22
Throttle pressure acts on the area difference between 2c to apply a downward force. Governor pressure is supplied to the ports 122i and 122j from the oil passage 430, and when the spool 222 is in the down position, the area of the land 222e
Governor pressure acts on the area where the area difference between land 222d and land 222d is felt (that is, equal to the area of land 222d), and when spool 222 is in the up position, governor pressure acts on the area of land 222e,
The spool 222 is pushed upward.
Port 12 with orifice 616 at the entrance
2f is connected to oil passage 432, and port 122g is connected to oil passage 434, and both ports 122f and 122g communicate with each other when spool 222 is in the up position. Oil passage 434 is connected to clutch C2. 2-3 shift valve 22 with such a configuration
controls the supply of pressure oil to the clutch C2 in accordance with its down and up positions, the details of which will be described later. The 3-4 shift valve 24 has ports 124a~
The valve hole 124 having a diameter k and the lands 224a~
d and is fitted into the valve hole 124 so as to be freely movable in the axial direction, and the valve hole 12
4, and a spring 324 disposed between the spool 224 and the plug 225. The lands 224a to 224c have the same diameter,
The land 224d has a larger diameter than the lands 224a to 224c. The port 124a is connected to an oil passage 420 which is a throttle pressure circuit, and the oil pressure of the port 124a acts on the end face of the plug 225 to push it downward in the figure. The port 124b is connected to the shuttle valve 5 via an oil passage 440.
It is connected to port 508c of 08. The oil pressure of this port 124b always acts on the upper side of the land 224a and pushes the spool 224 downward. The port 124c is connected to the clutch C3 via an oil passage 442 into which a low clutch pressure reducing valve 801 is inserted. This port 124c is connected to the spool 224
When in the up position, it communicates with the port 124d connected to the servo release chamber S/R of the brake B2 via the oil passage 444. port 124d
communicates with port 124e when spool 224 is in the down position. Port 124e is oil path 4
34 to clutch C2. Port 124f is connected to port 126d of 2-4 timing valve 26 via oil passage 446, and port 124g is connected to oil passage 442. Ports 124f and 124g communicate when spool 224 is in the up position. Further, the port 124g communicates with the port 124h connected to the oil passage 412 when the spool 224 is in the down position. Port 124i is a drain port. ports 124j and 124k
is connected to the oil passage 430 which is the governor pressure circuit, and is connected to the aforementioned 1-3 shift valve 20 and 2-3 shift valve 20.
Similar to shift valve 22, when spool 224 is in the down position, governor pressure acts on the area of land 224c, and when spool 224 is in the up position, governor pressure acts on the area of land 224d, pushing spool 224 upward. 3-4 of such a configuration
The shift valve 24 controls the supply of pressure oil to the clutch C3 and the servo release chamber S/R in accordance with its down position and up position, the details of which will be described later. 2-4 timing valve 26 is connected to port 126
Valve hole 126 having a to f and land 226
It consists of a spool 226 having a to c shape and fitted into the valve hole 126 so as to be freely movable in the axial direction. Lands 226b and 226c have the same diameter, and land 226a has a smaller diameter than these.
Ports 126a and 126c are drain ports, and port 126e is also a drain port, but an orifice 602 is provided in the middle of the drain oil path. An orifice 618 is provided in the oil passage 446. Throttle pressure is guided to the port 126b from an oil passage 420, which is a throttle pressure circuit, and the throttle pressure of this port 126b constantly acts on the area difference between the spools 226a and 226b, pushing the spool 226 downward in the figure. There is. The port 126d is connected to the oil passage 446,
When the spool 226 is in the down position, the port 126e
When the spool 226 is in the up position, the spool 226 communicates with the port 126c. Port 126f is oil path 4
34 to clutch C2. The 2-4 timing valve 26 with such a configuration is
During the 2-4 gear shift, pressure oil is supplied to clutch C2 and pressure oil is discharged from clutch C3 at predetermined timings, the details of which will be described later. 2-3 timing valve 28 is connected to port 128
Valve hole 128 having a to e and land 228
It consists of a spool 228 fitted in a valve hole 128 having numbers a to c so as to be movable in the axial direction, and a timing 328 for pushing the spool 228 upward in the drawing. Governor pressure is supplied to the port 128a from the oil passage 430, and the spool 228 receives downward force. On the other hand, throttle pressure is supplied to the port 128e from the oil passage 420, and the spool 228 receives an upward force. Port 128b is a drain port. Both ports 128c and 128d are connected to oil path 4.
34, but the port 128c is connected to the upstream side (closer to the 2-3 shift valve 22) of the check valve 750 and orifice 650 (both are provided in parallel) provided in the middle of the oil path 434. The port 128d is connected to the downstream side (the side closer to the clutch C2). The 2-3 timing valve 28 having such a configuration controls the pressure oil supplied to the clutch C2 according to the magnitude of the throttle pressure and the governor pressure, so that the 2-3 timing valve 28 controls the pressure oil supplied to the clutch C2.
To be fastened at a desired timing when changing gears. 3-4 timing valve 30 is connected to port 130
A valve hole 130 having a to e and a land 230
It consists of a spool 230 having a to c shape and fitted into the valve hole 130 so as to be movable in the axial direction, and a spring 330 that pushes the spool 230 upward in the figure. Governor pressure is supplied to the port 130a from the oil passage 430, and the spool 230 receives downward force. On the other hand, throttle pressure is supplied to the port 130e from the oil passage 420, and the spool 230 receives an upward force. Port 130b is a drain port. Ports 130c and 13d are both oil passage 4
42, but the port 130c is connected to the upstream side of the check valve 752 and orifice 652 (both are provided in parallel) provided in the middle of the oil passage 442 (port 124 of the 3-4 shift valve 24).
port 130d) and is connected to port 130d
is connected to the downstream side (the side closer to clutch C3). The 3-4 timing valve 30 having such a configuration controls the pressure oil discharged from the clutch C3 depending on the magnitude of the throttle pressure and the governor pressure, and the clutch C3 is released at a desired timing when the 3-4 gear is shifted. Do it like this. 3-2 timing valve 32 is connected to port 132
Valve hole 132 having a to e and land 232
It consists of a spool 232 having a to o shape and fitted into the valve hole 132 so as to be movable in the axial direction, and a spring 232 that pushes the spool 232 upward in the figure. Governor pressure is supplied to the port 132a from the oil passage 430, and the spool 232 receives downward force. On the other hand, throttle pressure is supplied to the port 132e from the oil passage 420 in opposition to this, and the spool 230 receives an upward force. Port 132b is a drain port. Both ports 132c and 132d are connected to the oil passage 434, but the port 132c is connected to a check valve 754 and an orifice 654 provided in the middle of the oil passage 434 (both are provided in parallel).
upstream side (port 12 of 2-3 shift valve 22)
The port 132d is connected to the downstream side (the side that directly communicates with the port 124e of the 3-4 shift valve 24). The 3-2 timing valve 32 having such a configuration controls the pressure oil discharged from the clutch C2 according to the magnitude of the throttle pressure and the governor pressure, and the clutch C2 is released at a desired timing during the 3-2 gear shift. Do it like this. The first speed fixed range pressure reducing valve 34 is connected to port 13.
Valve hole 134 having 4a to 4e and land 23
4a and 4b and are fitted into the valve hole 134 so as to be movable in the axial direction, and a spring 334 that pushes the spool 234 downward in the figure.
It has become so. Ports 134a and 134b are drain ports. Port 134d is oil path 4
16 (an oil passage to which line pressure is supplied when the manual valve 4 is in the position), and the ports 134c and 134e are connected to an oil passage 448. An orifice 620 is provided at the entrance of the port 134e. The single-speed fixed range pressure reducing valve 34 configured as described above uses the port 134d as a high-pressure port and the port 134b as a drain port for pressure regulation.
Make sure that the oil pressure of e balances the force of the spring 334. Therefore, the first speed fixed range pressure reducing valve 34
When line pressure is generated in the oil passage 416, the oil passage 4
48 has a function of generating hydraulic pressure reduced to a constant value. Torque converter pressure reducing valve 36 is connected to port 1
Valve hole 136 having 36a-e and land 2
36a and 36b and is fitted into the valve hole 136 so as to be movable in the axial direction, and a spring 336 that pushes the spool 236 to the left in the figure.
It consists of. Ports 136d and 136e
is the drain port. Port 136b is connected to oil passage 406 (port 102f of regulator valve 2).
The ports 136a and 136c are connected to the oil passage 45, through which pressure oil discharged from the oil passage 45 is supplied.
It is connected to the torque converter T/C via 0. An orifice 62 is installed at the entrance of the port 136a.
4 is provided. The torque converter pressure reducing valve 36 configured as described above uses the port 136b as a high pressure port and the port 136d as a drain port to perform a pressure regulating action so that the oil pressure of the port 136a is balanced with the force of the spring 336. Therefore, the torque converter pressure reducing valve 36
has a function of supplying pressure oil at a constant pressure to the torque converter T/C regardless of fluctuations in the oil pressure in the oil passage 406. The 1-2 accumulator 38 includes a stepped cylinder hole 138, a piston 238 fitted into the cylinder hole 138 so as to be movable in the axial direction, and a spring 338 that pushes the piston 238 upward in the figure.
It consists of. The large diameter chamber 138a defined by the piston 238 is connected to the oil passage 432, the small diameter chamber 138b is connected to the oil passage 402 (line pressure circuit), and the middle chamber 1
38c is a drain chamber. In addition, oil path 43
An orifice 656 and a check valve 756 are provided in parallel at the upstream portion of the 1-2 accumulator 38 and the servo apply chamber S/A. The 1-2 accumulator 38 having such a configuration is connected to the oil path 4.
32 hydraulic pressure (i.e. servo apply chamber S/A
It has a function that allows the oil pressure (hydraulic pressure) to rise gradually, allowing 1-2 gear shifts to be carried out smoothly. 3-4 Accumulator 40 has cylinder hole 14
0, a piston 240 fitted into the cylinder hole 140 so as to be movable in the axial direction, and a piston 2
40 upward in the figure. The upper chamber 140a in the figure divided by the piston 240 is connected to an oil passage 402 (line pressure circuit), and the lower chamber 140b is connected to an oil passage 442 (oil passage communicating with clutch C3). has been done. In addition, the clutch C3 of the oil passage 442
On the upstream side of the 4-3 accumulator 40, an orifice 658 and a check valve 758 are provided in parallel. The 4-3 accumulator 40 having such a configuration has a function of allowing the oil pressure in the oil passage 442 (hydraulic pressure in the clutch C3) to rise gradually, and allows the 4-3 gear shift to be performed smoothly in conjunction with the device of the present invention, which will be described later. This also reduces the shock when the manual valve 4 is moved from the N position to the D position. The overdrive inhibitor solenoid 42 is
Oil passage 402 and orifice 60, which are line pressure circuits
Opening 4 provided in oil passage 409 connected via 4
09a, and in the operating state, the rod 42a closes the opening 409a.
It is possible to close the In addition,
Oil passage 409 is connected to port 50 of shuttle valve 504
4b. The overdrive inhibitor solenoid 42 is operated by a switch SW that can be operated from the driver's seat. When the switch SW is off, oil flowing into the oil passage 409 through the orifice 604 is discharged from the opening 409a, so no pressure is generated in the oil passage 409.
Since the area of connection 604 is small, the line pressure will not be affected even if oil is discharged from opening 409a). When the switch SW is turned on, opening 4
09a is closed by the rod 42a,
Oil passage 409 has the same pressure as oil passage 402 (i.e.
line pressure). As a result, the 3-4 shift valve 24 is held in the down position as described below,
It is designed to prevent it from going into 4th gear (overdrive). Orifices 62 are installed at the entrances of clutch C1, clutch C3, and servo brining chamber S/A, respectively.
6, 628 and 630 are provided. Next, the structure and operation of the low clutch pressure reducing valve 801 and the third speed identification valve 802 that constitute the device of the present invention will be explained. The low clutch pressure reducing valve 801 is a low clutch C
Oil passage 442 that supplies working oil pressure (line pressure) to 3.
A spool 801 is installed in a valve hole that has a port 801a connected to the upstream side of the oil passage, a port 801b connected to the downstream side of the oil passage, and a drain port 801c.
d are slidably fitted together, and the spool 801
d has two adjacent lands 801e, 8 of the same diameter.
01f and one small diameter land 801g are provided.
The port 801b is always communicated between the lands 801e and 801f, and is communicated with the chamber 801h facing the land 801e via an oil passage 803, and the spool 801d is elastically supported in the right half position in the figure by the spring 801i toward the chamber 801h. do. In this spool position, the port 801a is positioned so that the port 801b communicates with the port 801a, and when the spool 801d resists the spring 801i and is moved to the left half position in the figure, and the land 801e closes the port 801a, the land 801f is connected to the drain port 801c. Position this drain port so that it opens. Also, land 8
The chamber 801 between 01f and 801g is communicated with the throttle pressure circuit 420 through an oil passage 804. The third speed identification valve 802 is a low clutch pressure reducing valve 8
A spool 802d is slidably fitted into a valve hole having a port 802a, a drain port 802b, and a port 802c connected via a circuit 805 to a chamber 801k in which a spring 801i of No. 01 is provided, and the spool is connected to a chamber 802f by a spring 802e. It is configured with a bullet support in the right half position in the figure. The spool 802d has a shape having two lands of the same diameter,
A port 802a is provided so that communication between these lands is constant.
At the same time, the port 802a is connected to the drain port 802 at the left half position of the spool 802d in the figure.
Position this drain port so that it communicates with b.
Further, the port 802c is positioned so as to communicate with the port 802a when the spool 802d is in the right half position in the figure, and the port 802c is connected to the line pressure circuit 402 through an oil passage 806. Further, the chamber 802f is connected to the oil passage 434 by an oil passage 807, and in the third and fourth gears when the high clutch C2 is operated (see the table above), the operating oil pressure (line pressure) is
Even though the spool 802d is moved to the left half position in the figure to allow the port 802a to communicate with the drain port 802b, since the high clutch C2 does not receive hydraulic pressure in other gears, the spool 802d
d is moved to the right half position in the figure by the spring 802e, allowing the port 802a to communicate with the port 802c. In the former position of the spool 802d, the low clutch pressure reducing valve 801 connects the chamber 801k to the drain port 80.
2b and is brought into a pressureless state, the hydraulic pressure toward the low clutch C3 can be reduced to a predetermined value by a pressure reducing action, which will be described later. However, even if the spool 802d is in the former position, this pressure reduction effect is not performed in the fourth gear because the low clutch operating pressure does not reach the port 801a, as will be described later and as is clear from Table 1 above. 801a, as will be described later, and as is clear from Table 1 above, the third
The above pressure reducing action is performed only when the speed is selected. In the latter position of the spool 802d, the low clutch pressure reducing valve 801 is supplied with line pressure from the oil passage 402 to the chamber 801k via the oil passage 806, so that the spool 801d is maintained at the right half position in the figure. , ports 801a and 801b are always communicated, and the above-mentioned pressure reducing action is not performed. The general operation of the hydraulic control system having the device of the present invention as described above will be explained. As mentioned above, the line pressure in the oil passage 402 is determined by the force acting upward in the figure on the spool 203, but the spool 203 is also supplied with the pressure modifier pressure from the pressure modifier valve 12 and Since the cutback pressure from the cutback valve 14 is acting, it changes in response to these pressures. Since the pressure modifier pressure and the cutback pressure each have the characteristics described above, the line pressure obtained varies up and down depending on the vehicle speed, but when expressed based on the throttle opening, it is already as shown in Figure 3. become that way. However, while driving in second gear with the manual valve 4 in or out of the D position, the pressure modifier pressure remains constant and the cutback pressure becomes 0, so the line pressure remains unchanged regardless of the throttle pressure and governor pressure. (In other words, under the above conditions, the pressure in the oil passage 428 is maintained by the action of the line pressure booster valve 16.
In order to generate line pressure in the oil passage 428, the line pressure in the oil passage 428 is changed by switching the shuttle valve 506.
Leads to 6. Therefore, line pressure is supplied to the port 112d of the pressure modifier valve 12, and as described above, the pressure modifier valve 12 supplies a constant pressure to the oil passage 411.
cause to occur. Also, since the line pressure of the oil passage 428 is supplied to the port 114e of the cutback valve 14, the spool 214 is pushed to the left in the figure, and the spool 215 is pushed to the right in the figure, and the oil passage 428 is pushed to the left in the figure.
10 communicates with the drain port 114b and the oil pressure becomes 0. ). Next, the operation at each position of the manual valve 4 will be explained. When the manual valve 4 is in the N position, the ports 104b, 104d, 1
Since line pressure is not supplied to either 04e or 104f and they are drain ports, hydraulic pressure is not supplied to either clutch or brake.
The automatic transmission is in a neutral state in which no power is transmitted. Next, when the manual valve 4 is switched from the N position to the D position, line pressure is supplied from the port 104c to the port 104d as described above, and this line pressure is supplied to the 1-3 shift valve 2 through the oil passage 412.
0 port 120g, 3-4 shift valve 24 port 124h, and governor valve 18. The governor valve 18 uses this line pressure to generate governor pressure corresponding to the vehicle speed as described above, and transmits this to each shift valve 2 via the oil passage 430.
0, 22 and 24. However, since the governor pressure is low while the vehicle speed is low, each shift valve 2
0, 22, and 24 are held in the down position by the throttle pressure acting downward in the figure.
Therefore, the port 120 of the 1-2 shift valve 20
The line pressure supplied to g is cut off by land 221b. On the other hand, the 3-4 shift valve 24
Since the port 124h communicates with the port 124g, line pressure is supplied to the oil passage 442, and the oil passage 442
line pressure passes through orifice 658 to low clutch C3. By the way, right now, High Clutch C2
Since pressure is not supplied to the oil path 434 to
The spool 802d of the third speed identification valve 802 is located at the right half position in the figure, and the spool 801d of the low clutch pressure reducing valve 801 is held at the right half position in the figure.
A and 801b are always communicated. Because of this,
The low clutch pressure reducing valve 801 is connected to the oil passage 44 as described above.
2, the line pressure toward the low clutch C3 is not reduced, but is allowed to reach the low clutch C3 as it is, and is strongly engaged so that the required clutch capacity described above in Table 2 is obtained. As a result, the state of the first forward speed is achieved by the operation of the low clutch C3 and the one-way clutch OWC as shown in Table 1 above. Note that the oil passage 442 is a 4-3 accumulator 40.
Since it also communicates with the chamber 140b, line pressure is supplied to the chamber 140b, and the oil passage 402 is connected to the chamber 140a.
The piston 2 of the 4-3 accumulator 40 is pushed downward in the figure by the line pressure acting on the piston 2.
40 is slowly moved upward by the force of spring 340. Therefore, the oil pressure on the downstream side of the orifice 658 will rise slowly, and the clutch C3 will be initially engaged at a relatively low oil pressure, so that the select shock when switching from the N position to the D position will be Reduced. When the automobile starts in the first gear state and the vehicle speed increases and the governor pressure reaches a certain value, the force due to the governor pressure acting upward on the spools 220 and 221 of the 1-2 shift valve 20 is applied to the spring 32.
0 and the throttle pressure acting on the area difference between the lands 220b and 220c from the port 120c, the spools 220 and 221 begin to rise from the down position. At that time, the land 221d of the spool 221
At the same time as the port 120j is cut off, land 2
21c opens the drain port 120i, the area of action of the governor pressure suddenly increases, and the spool 220
and 221 instantly rises to the left half position in the figure. Therefore, the ports 120g and 120h communicate with each other, and the line pressure of the oil passage 412 is introduced into the oil passage 432. The line pressure of the oil passage 432 is determined by the orifice 65.
6 and 630 to the servo abrasion chamber S/A. By doing this, brake B2
is activated, and the state of the second forward speed is achieved by the joint action with the clutch C3 which is in the above-mentioned engaged state. In addition,
The line pressure of the oil passage 432 is 1-2 accumulator 3
The piston 238 is also guided to the chamber 138a of No. 8, and is pushed back upward in the drawing by the line pressure acting on the chamber 138b from the oil passage 402. For this reason, the orifice 6 of the oil passage 432
The oil pressure in the portion downstream of 56 rises slowly, and the brake B2 operates slowly. This alleviates the shock (shift shock) when shifting from the first speed to the second speed. Also, in this second speed selection state, as in the first speed selection state, no oil pressure is applied to the oil passage 434 to the high clutch C2, so the third speed identification valve 802 and the low high clutch pressure reducing valve 801 are at the above spool position. can be maintained, and the clutch capacity of the low clutch C3 can be made to match the required value described above in connection with Table 2 above. When the vehicle speed further increases and the governor pressure reaches a certain value while driving in 2nd gear, the 2-3 shift valve 22
The force due to the governor pressure acting upward on the spool 222 of the
The spool 222 overcomes the downward force due to the throttle pressure acting on the area difference between the two positions, and starts rising from the down position. At this time, the land 222e of the spool 222 cuts off the port 122i, and at the same time the land 222d cuts off the drain port 122h.
To open the area, the area of action of the governor pressure suddenly increases, and the upward force increases, and at the same time, due to the area difference between the lands 222b and 222c, the port 122
The throttle pressure acting from e is transferred to port 122.
The spool 222 instantly rises to the left half position in the figure because the downward force is reduced by switching to the throttle modulate pressure (the oil pressure is somewhat lower than the throttle pressure) at d. Therefore, the ports 122f and 122g communicate with each other, and the oil passage 432
line pressure is introduced into the oil passage 434. Oil road 43
4 is in communication with clutch C2, so clutch C2 is engaged. In addition, the oil passage 434 is 3-4
It communicates with the port 124e of the shift valve 24, and this port 124e is connected to the 3-4 shift valve 2.
4 is in the down position, it communicates with the port 124d, so line pressure is also introduced into the oil passage 444 connected to the port 124d. Therefore, hydraulic pressure is supplied to the servo release chamber S/R connected to the oil passage 444, and the valve B2 is released. Therefore, clutches C2 and C3 are engaged, and the third speed condition as shown in Table 1 is achieved. By the way, when line pressure is generated in the oil passage 434 as described above, this line pressure keeps the spool 802d of the third speed identification valve 802 in the left half position in the figure, and keeps the chamber 801k of the low clutch pressure reducing valve 801 in an unpressurized state. . Therefore, the low clutch pressure reducing valve 801 receives the supply pressure to the low clutch C3 (hereinafter referred to as low clutch pressure PC3) which reaches the chamber 801h via the oil passage 803, and the throttle pressure which reaches the chamber 801i via the spring force of the spring 801i and the oil passage 804. The position of the spool 801d is determined by
The PC 3 can be reduced in pressure, for example, as shown by the dotted line in FIG. Therefore, when selecting 1st speed or 2nd speed, the line pressure shown by the solid line in FIG.
Low clutch C3, which had been supplied with PL, is now supplied with pressure PC3 (indicated by the dotted line in the middle of Figure 3) corresponding to about one-third of that when the third gear is selected, and the clutch of low clutch C3 at this time The capacity can be made to match the above-mentioned required value (approximately one-third of the time when the first and second speeds are selected) according to the second table. Note that when shifting from 2nd to 3rd speed, it is necessary to release brake B2 and engage clutch C2 at the same time, and if both are not activated at the appropriate timing, a large shift shock or engine racing may occur. or For this reason, a 2-3 timing valve 28 is provided in the middle of the oil passage 434 from the 2-3 shift valve 22 to the clutch CN. 2-3 Spool 22 of timing valve 28
8 is a downward force due to the action of governor pressure from the oil passage 430 led to port 128a and port 1
Depending on the magnitude of the upward force caused by the throttle pressure from the oil passage 420 guided to the oil passage 28e and the upward force exerted by the spring 328, the position is in the right half or the left half in the figure. In other words, when the accelerator pedal is depressed greatly and the throttle pressure is high, the 2-3 timing valve 28 is in the right half position in the figure, and the ports 128c and 128d are
The upstream side of the oil passage 434 (the side close to the port 122g of the 2-3 shift valve 22) and (the side close to the clutch C2) are connected by bypassing the orifice 650, and the clutch C2 is quickly engaged. be done. On the other hand, when the stroke amount of the accelerator pedal is decreased, the throttle pressure decreases and the 2-3 timing valve 28 is switched to the state shown in the left half of the figure, and communication between ports 128c and 128d is suddenly cut off. , and is connected to the upstream side of the oil passage 434 only through the orifice 650. Therefore, the hydraulic pressure of the clutch C2 increases slowly, and the engagement of the clutch C2 is slightly delayed. During this short period of time, the engine speed decreases, so the shift shock is reduced accordingly. That is, the 2-3 timing valve 28 has a function of reducing shock when shifting from second speed to third speed in a coasting state. In addition, 2-
3-4 from port 122g of shift valve 22
Oil passage 4 leading to port 124e of shift valve 24
A 3-2 timing valve 32, a check valve 754, and an orifice 654 are arranged in parallel in the middle of the port 3, and the direction of the oil flow from the port 122g to the port 124e allows the flow of the check valve 754. Since the directions match, regardless of the state of the 3-2 timing valve 2, hydraulic pressure is supplied to the servo release chamber S/R without being subjected to a throttling effect. When the vehicle speed further increases while driving in third gear and the governor pressure reaches a certain value, the 3-4 shift valve 24
The force due to the governor pressure acting upward on the spool 224 overcomes the downward force due to the throttle pressure acting on the upper end surface of the plug lug 225 from the port 124a, and the spool 224 begins to rise from the down position. Note that, when the throttle pressure is small, the force exerted by the spring 324 becomes larger than the above-mentioned downward force, so that the plug 225 is pushed upward, and only the constant force exerted by the spring 324 is exerted. When the spool 224 rises, the land 224d of the spool 224 cuts off the port 124j, and at the same time the land 224c opens the drain port 124i, so the area of action of the governor pressure suddenly increases, the force in the direction becomes large, and the spool 22
4 instantly reaches the up position in the left half of the figure. Therefore, the port 124d connected to the servo release chamber S/R communicates with the port 124c connected to the oil passage 442. In addition, the oil path 44
Port 124g connected to 2 is port 124f
communicate with. Therefore, both clutch C3 and servo release chamber S/R communicate with port 124f. Port 124f is connected to 2-4 via oil passage 446.
It is connected to the port 126d of the timing valve 26, but since the 2-4 timing valve 26 is pushed up by the oil pressure acting on the port 126f from the oil passage 434 and is in the right half position in the figure, the port 126d is a drain port. Port 126c is
It communicates with Therefore, the hydraulic pressure in clutch C3 and servo release chamber S/R is discharged together, and as clutch C3 is released, brake B is released.
2 is concluded. As a result, the clutch C2 and the brake B2 are operated to achieve the fourth speed state as shown in Table 1 above. At this time, the hydraulic pressure of the clutch C3 flows through the check valve 758 in the forward direction (direction that allows flow) and is quickly discharged.
On the other hand, in the middle of the oil passage 442 from the port 124c to the port 124g, there is a 3-4 timing valve 30, a check valve 752, and an orifice 65.
2 are provided in parallel, so depending on the position of the 3-4 timing valve 30, the servo release chamber S/R
The hydraulic discharge speeds of are different. The configuration of the 3-4 timing valve 30 is basically the same as the timing valve 28 described above, and in the acceleration state, the ports 124c and 124g communicate with each other by bypassing the orifice 652, while in the coasting state, the ports 124c and 124g communicate with each other, bypassing the orifice 652. 124g (so both ports are connected via orifice 652). Therefore, in the coasting state, the oil in the servo release chamber S/R gradually decreases, and the engagement of the brake B2 is slightly delayed from the release of the clutch C3. During this short period of time, the engine speed decreases, so the shift shock is reduced accordingly. Note that even in this fourth speed selection state, the third speed identification valve 8
02, the spool 802d is moved to the left half position in the figure by the line pressure in the oil path 434 to the high clutch C2, and the chamber 80 of the low clutch pressure reducing valve 801 is moved to the left half position in the figure.
In order to keep C1k in an unpressurized state, the low clutch pressure reducing valve 801 can perform a pressure reducing action in the same manner as in the third gear. The spool 801d is kept at the right half position in the figure by the spring 801i without creating pressure on the spool 801d.
The above-mentioned pressure reduction action is not performed. Therefore, the third speed identification valve 802 is activated when the high clutch C2 is actuated.
The low clutch pressure reducing valve 8 responds to the operating oil pressure (line pressure) in both 5th and 4th speeds, but only in 3rd speed.
01 will be applied to reduce the pressure. Next, the operation of the 2-4 timing valve 26 will be explained. If the throttle pressure is suddenly reduced while the vehicle is running in second gear, the 2-3 shift valve 22 and the 3-4 shift valve 24 may be simultaneously switched from the down position to the up position. That is,
Shifts directly from 2nd gear to 4th gear. In this case, clutch C3 is released and clutch C2 is engaged. In order to prevent the gear shift shock and engine from racing, it is necessary to release clutch C3 and release clutch C2.
It is necessary to perform the tightening at a predetermined timing. The oil pressure of the clutch C2 increases due to the oil sent from the 2-3 shift valve 22 through the oil passage 434, but the oil pressure of the clutch C2 increases through the port 126f of the 2-4 timing valve 26.
I am also guided by 2-4 timing valve 26
In the second speed state, the throttle pressure introduced to the port 126b pushes down to the position shown in the left half of the figure. Therefore, ports 126d and 12
6e, and the hydraulic pressure of clutch C3 is
Oil passage 442, port 12 of 3-4 shift valve 24
4g and 124f, oil passage 446, ports 126d and 126e of 2-4 timing valve 26, and orifice 602. Therefore,
The hydraulic pressure of the clutch C3 is throttled by the orifice 602 and initially flows out slowly. However, when the oil pressure of the clutch C2 increases and exceeds a predetermined value, the 2-4 timing valve 26 is pushed to the position shown in the right half of the figure. Therefore, the hydraulic pressure of the clutch C3, which has been discharged through the port 126e, is now discharged through the port 126c and is no longer affected by the throttling effect of the orifice 602, so that the hydraulic pressure of the clutch C3 rapidly decreases. Therefore, after clutch C2 starts to engage, clutch C3 will be released.
No large gear shifting shocks or engine racing occurs. In addition, 2-4 timing valve 2
The pressure in clutch C2 when 6 switches from the left half to the right half in the figure increases as the throttle pressure increases, so the smaller the stroke amount of the accelerator pedal, the sooner clutch C3 is released and the clutch remains in neutral for a short time. During this period, the engine rotational speed decreases in proportion to the vehicle speed, so the shift shock becomes smaller. Above, we have explained the operation of gradually changing gears from 1st gear to 4th gear (upshifting), but next we will reverse the gear shifting from 4th gear to 1st gear (downshifting).
I will explain the actions that will be taken. When the governor pressure decreases or the throttle pressure increases while driving in fourth gear, the 3-4 shift valve 24 is switched from the up position to the down position, and the oil passage 4 is switched from the up position to the down position.
12 line pressure is applied to clutch C via oil passage 442.
3 is supplied to the clutch C3, and the line pressure of the oil passage 434 is supplied to the servo release chamber S/R via the oil passage 444, thereby releasing the brake B2. This results in the third speed state in which clutches C2 and C3 operate. At this time,
The line pressure that operates the clutch C2 moves the spool 802d of the third speed identification valve 802 to the left half position in the figure, and the chamber 801 of the low clutch pressure reducing valve 801
Since the low clutch pressure reducing valve 801 performs the pressure reducing action described above, the low clutch pressure (the working oil pressure of the clutch C3) PC3 is maintained at the third pressureless state.
If the clutch capacity of the low clutch C3 is lowered as shown by the dotted line in the figure to match the required value, and the low clutch C3 is switched from inoperative to operative during the gear shift, the shift shock can be alleviated. This shift shock reduction is achieved by reducing the rise of the hydraulic pressure PC3 of the clutch C3 by 4-3 accumulator 4.
This is further aided by easing the following operation of 0. That is, in the fourth speed state, the piston 240 of the 4-3 accumulator 40 is pushed down by the line pressure in the chamber 140a because the oil pressure in the chamber 140b is drained through the oil passage 442. However, 3-4 shift valve 24
When the oil pressure is switched as described above and hydraulic pressure is generated in the oil passage 442, the force of the spring 340 pushes it up. During this time, the oil pressure in the oil passage 442, that is, the oil pressure toward the port 801a of the low clutch pressure reducing valve 801, increases slowly, and the low clutch pressure reducing valve 801 reduces this oil pressure as described above and supplies it to the low clutch C3, so that the clutch C3 It is gradually engaged, and the shift shock during the shift can be completely eliminated. While driving in third gear, if the governor pressure further decreases or the throttle pressure increases, the 2-3 shift valve 22 is switched from the up position to the down position.
The oil pressure in the oil passage 434 is discharged to the drain port 122h. Therefore, the hydraulic pressure acting on the clutch C2 disappears, the clutch C2 is released, and the servo release chamber S/R of the brake B2 is released.
The oil pressure of the oil passage 444, ports 124d and 124
e and is discharged through the oil passage 434, so the brake B2 is activated. Therefore, the state of the second speed is reached in which the clutch C3 and the brake B2 are activated.
In addition, the discharge of pressure oil from the servo release chamber S/R is as follows.
3-2 timing valve 32 provided in oil passage 434
controlled by. That is, the 2-3 timing valve 32, the check valve 754, and the orifice 654 are provided in parallel in the middle of the oil passage 434 from the port 124e of the 3-4 shift valve 24 to the port 122g of the 2-3 shift valve 22. When the -2 timing valve 32 is in the left half position in the figure, the port 124e and the port 122g communicate with each other bypassing the orifice 654, and when the 3-2 timing valve 32 is in the right half position in the figure, the port 124e and the port 122g communicate with each other, bypassing the orifice 654.
24e and port 122g are separated at the 3-2 timing valve and communicate only through orifice 654. 3-2 timing valve 32
When the force due to the throttle pressure acting on the port 132e is larger than the force due to the governor pressure acting on the port 132a (i.e., in an acceleration state),
The position is in the right half of the figure, and in the opposite case (that is, coasting state), the position is in the left half of the figure. Therefore, in the acceleration state, the oil pressure in the servo release chamber S/R is discharged through the orifice 654, so that the oil pressure in the servo release chamber S/R slowly decreases. For this reason, the operation of brake B2 is slightly delayed (the hydraulic pressure of clutch C2 is
(It is quickly discharged through the check valve 750), the engine becomes in a neutral state, albeit for a short time, and the engine rotation increases in accordance with the vehicle speed. As a result, fluctuations in engine rotational speed during gear shifting are reduced, and gear shifting shocks are reduced. When the governor pressure further decreases or the throttle pressure increases while driving in second gear, the 1-2 shift valve 20 is switched from the up position to the down position.
The hydraulic pressure in the oil passage 432 is discharged to the drain port 120i. As a result, the hydraulic pressure discharged to the servo brining chamber S/A disappears, and the brake B2 is released. As a result, only the clutch C3 becomes engaged, and the first speed state is achieved in cooperation with the one-way clutch OWC. Next, we will explain the effect during kickdown when the stroke of the accelerator pedal is 7/8 or more. When the accelerator pedal is fully depressed, the plunger 207 of the throttle valve 6 is pushed to the right in the figure, resulting in the state shown in the upper half of the figure, the throttle valve is in a non-pressure regulating state, and there is no line in the oil passage 420. pressure is supplied. Oil line 420 to port 1
The line pressure sent to 08a is supplied to oil passage 418, which is a kickdown pressure circuit, through port 108e. The line pressure of the oil passage 418 is supplied to the port 120b of the 1-2 shift valve 20 and the port 122c of the 2-3 shift valve 22, and is also supplied to the 3-3 shift valve 20 through the shuttle valve 508 and the oil passage 440.
It is supplied to the port 124b of the 4-shift valve 24. When line pressure is supplied to the port 124b of the 3-4 shift valve 24, the plug 225 is pushed upward in the figure, and the spool 224 is pushed downward. No matter how high the vehicle speed is, the governor pressure will never be higher than the line pressure, so the spool 224 is held in the down position as long as it is in the down position. Therefore, if the gear is turned down while running in the 4th gear, the gear will always be lower than the 3rd gear, and as long as the gear is kicked down, the gear will not change from the 3rd gear to the 4th gear. The supplied kickdown pressure (line pressure) acts on the difference in area between lands 222a and 222b of spool 222 to push spool 222 downward. Therefore, since a downward force is added, the 2-3 shift valve 22 will not be switched unless the governor pressure that applies the upward force increases by that amount. That is, in the kickdown state, the vehicle speeds for 2-3 and 3-2 gear shifts are significantly higher than in the non-kickdown state. Note that the kickdown pressure in the oil passage 418 is also supplied to the port 110b of the throttle modulator valve 10, so the throttle modulator valve 10 is in a non-pressure regulating state, and the throttle modulate pressure has been supplied until now. Line pressure is generated in the oil passage 424, which had been Therefore, the 2-3 shift valve 22
Line pressure is supplied to the port 122d of the spool 22, and line pressure is also supplied to the port 122e (up to now it was throttle pressure, but it has become line pressure due to kickdown).
The same hydraulic pressure acts on the difference in area between the two lands 222b and 222c both in the up position and in the down position, and the difference in governor pressure between moving up and down is small. That is, during kickdown, the hysteresis between the 2-3 and 3-2 gear shifts becomes smaller.
The kickdown pressure supplied to port 120b of 1-2 shift valve 20 acts on the area difference between lands 220a and 220b when spool 220 is in the down position, and acts on the area difference between lands 220a and 220b when spool 220 is in the up position. It acts on the area difference between lands 220b and 220c and pushes spool 220 downward. Therefore, the 1-2 shift valve 20 will not switch unless the governor pressure that applies the downward force becomes that much higher. That is, in the kickdown state, the vehicle speed at which the 1-2 shift and the 2-1 shift are performed becomes significantly higher than in the non-kickdown state. Next, overdrive inhibitor solenoid 4
The effect of 2 will be explained. As mentioned above, when the solenoid 42 is turned on, line pressure is generated in the oil passage 409. The oil pressure in the oil passage 409 is applied to the port 124b of the 3-4 shift valve 24 through the shuttle valve 504, the shuttle valve 508, and the oil passage 440.
, the plug 225 is pushed upward in the figure, and the spool 224 is pushed downward. Therefore, regardless of the magnitude of the governor pressure, the 3-4 shift valve 24 is held in the down position and does not enter the fourth speed state. Therefore, if the driver does not wish to drive in the fourth speed (overdrive) depending on driving conditions, the driver can prevent the vehicle from going into the fourth speed by operating the switch SW. Next, set the manual valve 4 to the D position and set it to the third position.
The effect when the manual valve 4 is set to the position while the vehicle is running in the first or fourth gear will be explained. When manual valve 4 is positioned, port 1
Since line pressure is generated in the port 104e in addition to the port 104d, the line pressure is supplied to the oil passage 414. The line pressure of the oil passage 414 is controlled by the shuttle valve 5.
04, reaches the port 124b of the 3-4 shift valve 24 via the shuttle valve 508 and the oil passage 440. When line pressure is applied to port 124b, spool 224 is placed in the down position, as in the case of kickdown and activation of overdrive inhibitor solenoid 42 described above. In addition, the line pressure of the oil passage 414 is also guided to the port 122a of the 2-3 shift valve 22, so
It acts on the upper end of the plug 223 to push the plug 223 and spool 222 down to the down position in the right half of the figure. Therefore, the automatic transmission is in the second speed state and will not be shifted to the third or fourth speed regardless of the vehicle speed. Note that the line pressure of the oil passage 414 is also guided to the port 116e of the line pressure booster valve 16, but the line pressure booster valve 16 is led to the port 116b.
The state shown in the lower half of the figure is due to the hydraulic pressure acting on the port 116 (hydraulic pressure in the oil passage 432).
The oil pressure of e is guided to the port 116d, and the oil pressure is passed through the oil path 423.
generates line pressure. As a result, as mentioned above, the line pressure is at its highest regardless of the throttle opening, so valve B2, which is a band brake, can be operated strongly even when the throttle opening is small, and the second speed Shifting to and fro is quick and the engine valves can be activated immediately. Even when the manual valve 4 is in the above position, the relationship between the oil pressures acting on the 1-2 shift valve 20 is exactly the same as when the manual valve 4 is in the D position, so the 1-2 shift valve 20 is Switches depending on the magnitude of governor pressure and throttle pressure. Therefore, even when the manual valve 4 is in the position, automatic shifting between the first speed and the second speed is performed. As mentioned above, if the manual valve 4 is moved from 4th or 3rd gear to 2nd gear, the line pressure will be higher regardless of the throttle opening, but once the 1st gear is reached, When shifting to the second speed, the line pressure becomes the same pressure as in the case of the D position in the following manner. When shifting from 2nd gear to 1st gear (i.e., the 1-2 shift valve 20
is in the down position), the hydraulic pressure in the oil passage 432 is discharged to the port 120i. For this purpose, the spool 21 is inserted through the port 116b of the line pressure booster valve 16 and the hole 216d of the spool 216.
The hydraulic pressure that was acting on the left end in the figure of 6 disappears, and the spool 216 is pushed to the left by the spring 316 to the upper half position in the figure. Therefore, oil passage 414
The connection between the oil passage 428 and the oil passage 428 is cut off, and the oil passage 428
The hydraulic pressure is discharged to port 116c. Therefore, the pressure modifier valve 12 and the cutback valve 14 operate in the same manner as when the manual valve 4 is in the D position. In this state, even if the 1-2 shift valve 20 returns to the up position and hydraulic pressure is generated in the oil passage 432, the port 116 of the line pressure booster valve 16
b is cut off by the land 216b of the spool 216, so the line pressure booster valve 16 remains in the upper half position in the figure. Therefore, in this case, the line pressure does not rise to the maximum value even in the second gear. By doing this, the shift shock between the first and second speeds at the position of the manual valve 4 is made equal to the shift shock at the D position. Next, when the manual valve 4 is set to the position, line pressure is generated not only in the ports 104d and 104e but also in the port 104f.
16 is supplied with line pressure. The line pressure of the oil passage 416 is the port 1 of the 1st speed fixed range pressure reducing valve 34.
34d. This line pressure is
4c and the oil passage 448 to reach the port 134e, push the spool 234 upward in the figure, and balance the spool 234 with the drain port 134b slightly open. Therefore, port 134
The oil pressure of e (that is, the oil pressure of the oil passage 448) has a constant value (lower than the line pressure) corresponding to the force of the spring 334. This constant pressure in the oil passage 448 is maintained between the shuttle valve 502 and the oil passage 43.
6 through port 12 of 1-2 shift valve 20
0d, the land 221a of the spool 221
acts on the upper side of the spool 221 and pushes the spool 221 downward.
Therefore, when the governor pressure pushing the spool 221 upward is below a certain value, the spool 221 is pushed down to the down position (the spool 220 remains in the up position). As a result, the oil passage 43
2 line pressure is discharged to drain port 120i, and brake B2 is released. At the same time,
1-2 Ports 120d and 20 of shift valve 20
e is in communication, and the constant pressure in the oil passage 436 is supplied to the brake B1 via the oil passage 438. Therefore, the automatic transmission is in the first speed (first speed in which the engine brake can be applied) in which the clutch C3 and the brake B1 are activated. Note that when the governor pressure is above the above-mentioned constant value, the spool 221 will not switch even if the constant pressure from the first speed fixed range pressure reducing valve 34 acts on the port 120d, so the manual Even if the valve 4 is set to the position, the first speed will not be reached, and overrun of the engine can be prevented. Next, the operation when the manual valve 4 is moved from the N position to the R position will be explained. When manual valve 4 is in R position, port 104b
Line pressure is generated only in the oil passage 4.
08 to clutch C1, and oil passage 408;
1 via the shuttle valve 502 and the oil passage 436.
-2 is led to the port 120d of the shift valve 20. This oil pressure acting on the port 120d always moves the spool 221 of the 1-2 shift valve 20 to the down position (the governor pressure is
12 is not generated because the line pressure does not exist), the oil passage 436 and the oil passage 438 are in communication,
Line pressure is supplied to valve B1. Therefore, the clutch C1 and the brake B1 are operated, and the first
The automatic transmission goes into reverse just like the speed. (6) Effects of the Invention Thus, as described above, the device of the present invention is capable of controlling a plurality of lower gears (first gear, second gear, second gear, etc.) below a certain gear (third gear).
The low clutch C3 is hydraulically actuated in the third gear, but the input torque ratio is smaller in the certain gear than in other low gears, and the low clutch C3 is hydraulically operated in the above-mentioned certain gears than in other low gears. In an automatic transmission equipped with a high clutch C2 which is operated at a high speed), a high clutch operation discrimination valve 802 generates an output pressure when the high clutch C2 is not actuated and dissipates the output pressure when it is actuated in response to the actuation or non-operation of the high clutch C2. , and a low clutch pressure reducing valve 801 that reduces the hydraulic pressure to the low clutch C3 while the output pressure disappears, and stops this pressure reducing action while the output pressure is generated. If the input torque ratio of the low clutch C3 becomes small, the clutch capacity can be adjusted to the required clutch capacity commensurate with the input torque ratio at that certain gear, and therefore the low clutch C3 changes from the non-operating state to the operating state. It is possible to reliably reduce the shift shock at the time of downshift shifting to a certain gear position. By the way, in low gears (first gear, second gear) that are lower than a certain gear mentioned above, the high clutch operation identification valve 802 stops the pressure reducing action of the low clutch pressure reducing valve 801. The clutch capacity will not be reduced unnecessarily and problems such as slippage will not occur. The pressure reducing action is stopped by locking the low clutch pressure reducing valve 801 at the corresponding limit position, but the hydraulic pressure of the high clutch C2 cannot be used as the hydraulic pressure for locking (in the first and second speeds mentioned above). Even in automatic transmissions of this type (because the high clutch is not activated), the present invention provides a high clutch identification valve
By adopting 02, the above-mentioned low clutch pressure reducing valve can be locked with its output pressure. Incidentally, when the device of the present invention is used together with the accumulator 40 as shown in the example in the figure, the effect of reducing the shift shock is further enhanced, and the shift shock can be almost completely eliminated. In this case, the accumulator 40 is
Since the clutch capacity of the low clutch C3 matches the required value, it can be extremely small and there is no need to make it as large as when used alone, so even if an accumulator is used, this is an automatic transmission. This does not interfere with the machine's mission of making it more compact.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram illustrating a power transmission mechanism of an automatic transmission whose shift shock is to be reduced by the device of the present invention, and Fig. 2 shows the device of the present invention incorporated into a hydraulic circuit that performs shift control of the same mechanism. Shift control hydraulic circuit diagram, FIG. 3 is a comparison diagram showing the low clutch pressure reduced by the device of the present invention together with the line pressure of the automatic transmission. T/C...Torque converter, E...Engine output shaft, I...Input shaft, O...Output shaft, G1, G
2... Planetary gear set, S1, S2... Sun gear, R
1, R2...Internal gear, PC1, PC2...
...Carrier, P1, P2...Pinion gear, C1
...First clutch, C2...Second clutch (high clutch), C3...Third clutch (low clutch), B1...First brake, B2...Second brake, OWC...One-way clutch, O/P...
...Oil pump, SW...Overdrive inhibitor switch, S/A...Servo apply chamber,
S/R... Servo release chamber, 2... Regulator valve, 4... Manual valve, 6... Throttle valve, 8... Throttle fail safe valve, 14... Cutback valve, 16...
Line pressure booster valve, 18... Governor valve, 20... 1-2 Shift valve, 22... 2-
3 shift valve, 24...3-4 shift valve,
26...2-4 timing valve, 28...2-
3 timing valve, 30...3-4 timing valve, 32...3-2 timing valve, 34
...1st speed fixed range pressure reducing valve, 36...torque converter pressure reducing valve, 38...1-2 accumulator, 40...4-3 accumulator, 42...
...Overdrive inhibitor solenoid, 402
...Line pressure oil path, 420...Throttle pressure oil path, 434...High clutch operating pressure oil path, 442
...Low clutch operating pressure oil path, 801...Low clutch pressure reducing valve, 801a, 801b...Connection port, 801c...Drain port, 801d...Spool, 801h, 801j, 801k...Chamber,
801i... Spring, 802... Third identification valve (high clutch operation identification valve), 802a, 802c...
Connection port, 802b...Drain port, 802
d...Spool, 802e...Spring, 802f...
...Room, 803-807... Oil road.

Claims (1)

[Scope of Claims] 1. A low clutch that is hydraulically operated at a plurality of low gears below a certain gear and whose input torque ratio is smaller in the certain gear than in other low gears; an automatic transmission comprising a high clutch that is operated in a high speed gear; The low clutch pressure reducing valve reduces the hydraulic pressure toward the low clutch while the output pressure of the high clutch operation identification valve disappears, and stops this pressure reducing action while the output pressure is generated. Shift shock reduction device for automatic transmission.