JPS645179B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a shift valve for a hydraulic control device for an automatic transmission. A conventional shift valve for an automatic transmission is disclosed in, for example, Japanese Patent Application Laid-Open No. 55-47038.
The shift valve shown here is composed of a spool and a plug provided in one spool hole, and is configured so that a down position holding signal hydraulic pressure can be introduced into the port between the spool and the plug. ing. Thereby, when hydraulic pressure is applied to the port, the spool is forcibly switched to the down position. However, such conventional shift valves have
There are the following problems. In other words, the pressure receiving area of the land on which the spool down position holding signal hydraulic pressure acts is equal to the pressure receiving area of the land on which the governor pressure on the other end of the spool acts, and when the down position holding signal hydraulic pressure acts, the spool is always switched to the down position. Therefore, when the down position holding signal hydraulic pressure is output, the vehicle is switched to the down position regardless of the vehicle speed. For example, when driving in 3rd gear at a high speed of 100 km/h or more, if the down position holding signal hydraulic pressure is output by operating the select lever, the 2nd
This means that it can be switched quickly. Therefore, there is a possibility that the engine will overrun if the vehicle is forcibly downshifted to second gear while driving at high speed. Furthermore, in this conventional shift valve, the spool and plug operate as one body except when forcing the second speed, and the shift line is determined as a function of governor pressure and throttle pressure. Therefore, there is a problem in that when the throttle opening is low, the vehicle speed on the shift line becomes very low, making it impossible to obtain a desired shift line. The present invention has been made by focusing on the above-mentioned problems with conventional shift valves, and the pressure receiving area of the spool on which the down position holding signal oil pressure acts is made smaller than the pressure receiving area on which governor pressure acts. The purpose of this invention is to solve the above problems by making the spool have a structure with hysteresis and by making the spool and plug separate at low throttle openings. Figure 1 shows 4 forward speeds and 1 reverse speed with overdrive.
This figure shows the power transmission mechanism and framework of a high-speed automatic transmission. 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.
Planetary gear set G2, first clutch C1, second clutch C2, third clutch C3, first brake B1,
2nd brake B2 and one-way clutch
Has OWC. The first planetary gear set G1 includes a sun gear S1, an internal gear R1, and a pinion gear P1 that meshes with both gears S1 and R1 simultaneously.
It consists of a carrier PC1 that supports
The planetary gear set G2 also includes a carrier that supports a sun gear S2, an internal gear R2, and a pinion gear P2 that meshes with both gears S2 and R2 at the same time.
It consists of PC2. Carrier PC1 can be connected to input shaft I via clutch C2,
The sun gear S1 can also be connected to the 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 Bucherer brake B2 can fix sun gear S1.
It is possible to fix the The one-way clutch OWC has a structure that allows the carrier PC1 to rotate forward (rotation in the same manner as the engine output shaft E) but does not allow reverse rotation (forward rotation and rotation in the customer direction (i.e., a structure that acts as a brake only when reversed). 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】

[Table] In the above table, the ○ mark indicates the clutch and brake that are in operation, and α1 and α2 are sun gear S corresponding to the number of teeth of internal gears R1 and R2, respectively.
1 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. Furthermore, 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 activated. However, in the first speed in this case, it is not possible to drive from the output shaft O side (that is, the engine brake is not effective). FIG. 2 is a hydraulic circuit diagram of a hydraulic control device for controlling the power transmission mechanism. This hydraulic control device includes a regulator valve 2,
Manual valve 4, throttle valve 6, throttle fuel safety 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 26, 2-3 timing valve 28, 3-4 timing valve 30, 3-2 timing valve 3
2. 1st speed fixed range pressure reducing valve 34, torque converter pressure reducing valve 36, 1-2 accumulator 3
It has an 8, 4-3 accurator 40, and an overdrive inhibitor solenoid 42, and each of these valves is connected to each other as shown in FIG. 2, and an oil pump O/P, torque converter T/C, and clutch C1, C2 and boo rake B
1 and B2 are also connected as shown.
The brake B2 includes a servo apply chamber S/A, which is a hydraulic chamber for applying the brake, and a servo release chamber S/A, which is a hydraulic chamber for releasing the brake.
(The pressure receiving area of the servo release chamber S/R is larger than the pressure receiving area of the servo apply chamber S/A, so when hydraulic pressure is supplied to the servo release chamber S/R, the pressure receiving area of the servo apply chamber S/A Brake B2 is released even if hydraulic pressure is supplied to the brake B2. 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; A spring seat 254 disposed at the upper end of the sleeve 252 in the figure, and a land 2 of the spring seat 254 and the spool 202.
02d 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 102d is connected to the oil pump O/through the oil passage 404.
It is connected to the variable capacity oil chamber C/C of P. 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. Note that an orifice 608 is provided in the oil passage 406. Port 102h is connected to ports 114c and 114g of cutback valve 14 via oil passage 410, and port 102i is connected to port 114a of cutback valve 14 via oil passage 411.
and 114d, and ports 112c and 112e of the pressure modifier valve 12. 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 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 oil pressure of the port 102b becomes high and the downward force becomes larger than the upward force, the spool 202 moves slightly downward, forming a gap between the land 202d and the port 102f, and from this gap the port The oil in port 102e flows out and the oil pressure in port 102e decreases, but since port 102e communicates with port 102b through oil passage 402, the oil pressure in port 102b eventually decreases.
Since the downward force becomes smaller, the 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 (i.e. line pressure) obtained in this way is
Since the force caused by 2 is constant, it will change depending on the upward force caused by spool 203. The ports 102h and 102i of the valve hole 102 are located at the port 252a of the sleeve 252, respectively.
and 252b, the oil pressure of the oil passage 410 acts on the area difference between the lands 203a and 203b of the spool 203, and the land 203b
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, the line pressure is controlled according to the oil pressure in the 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
Halb hole 104 having 4f and Halb 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 set to a parking position P, a reverse travel position R, a neutral position N, a forward automatic shift travel position D, a 2nd gear position II, and a 1st gear position I. It is set to stop at position 6. 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 individual 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 O in the above table, and all other ports are connected to drain ports. 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 pushing force of the spring 307 is obtained, but since the pushing force of the spring 307 is variable by the plunger 207 that is linked to the accelerator pedal, the hydraulic pressure in the oil passage 420 ultimately depends on the amount of depression of the accelerator pedal ( The oil pressure (i.e., throttle pressure) is proportional to the throttle opening. The characteristics of this throttle pressure are shown by the solid line in FIG. 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 422. Further, the port 108e is connected to the oil passage 418, which is the aforementioned kickdown circuit. The throttle fuel safety valve 8 having such a configuration normally has the function of reducing the pushing force of 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. At the time of kick-down, the planer gear 207 is pushed to the position shown in the upper half of the figure, thereby opening the port 10.
8e and port 108a communicate through the inner diameter of 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 at the time of kickdown, the spool 206 of the aforementioned throttle valve 6 is also pushed in as shown in the upper half of the figure, and the ports 106d and 106c are
The 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 (upper half position in the figure), the ports 108c and 108d are connected to the lands 208a and 208 of the sleeve 208.
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 422.
Line pressure is sent from 02, and as described later, 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. I can do it. (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 310 that presses the spool 210 to the left in the figure. Land 210a is connected to lands 210b and 2
The diameter is larger 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 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. An orifice 612 is provided at the entrance of the port 110e. Throttle modulator valve 1 with such a configuration
0, since the port 110b is a drain port via the oil passage 418 when the engine is not in a kickdown state, the port 110d is set as a high pressure side port (throttle pressure is supplied) and the port 110b is adjusted as a drain port. Perform pressure action. The balance of the spool 210 is determined by adjusting the oil pressure (throttle pressure) of the port 110a to the land 210.
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 depending on the throttle pressure, and has characteristics as shown by the broken line in FIG. 3. This throttle modulate pressure is
As described above, the oil is sent to the 2-3 shift valve 22 through the oil passage 424, and is used to control the switching thereof. 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 used as a high pressure side port (throttle pressure or line pressure is supplied as described later), and the port 112d
1b is used as a drain port to perform pressure regulation. The balance of spool 212 is
The hydraulic pressure of e 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 is 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 has characteristics as shown in FIG. If the accelerator pedal linkage fails, the throttle fuel fail-safe valve 8 switches to close the oil passage 4 as described above.
Since line pressure is supplied to 22, the pressure modifier pressure remains constant. Furthermore, when the manual valve 4 is switched from the D position to the D position as described later, line pressure is supplied from the line pressure booster valve 16 to the port 506b of the shuttle valve 506 via the oil passage 428, so the oil passage 4
Port 11 regardless of the throttle pressure value of 22.
Line pressure is supplied to 2d, and the pressure modifier pressure becomes constant. 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
When the manual valve 4 is not in the position or 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 set to high pressure. In addition, the port 114b is used as a drain port to perform pressure regulation. Spool 214
and 215 act like a single spool, and the rightward force exerted by the pressure modifier pressure of the port 114a on the land 214a is
The hydraulic pressure of the port 114g balances the leftward force of the force acting on the land 215b, and the hydraulic pressure (governor pressure) of the port 114f acts on the area difference between the lands 215a and 215b. Therefore, when the governor pressure increases, the oil pressure at port 114g (hereinafter referred to as
The cutback pressure (hereinafter referred to as "cutback pressure") decreases, and when the governor pressure exceeds a certain value, the cutback pressure becomes zero, as shown in the lower half of the figure. Also,
The cutback pressure decreases as the preload modifier pressure decreases. The characteristics of this cutback pressure are shown in FIG. 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 prepressure 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 in the oil passage 410 is 0 regardless of the governor pressure and the pre-modifier pressure.
become. Line pressure booster valve 16 is connected to port 116
Halb hole 116 having a to f, and Halb 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 2nd speed position (up side).
The port 116a is connected to the port 122g of the 2-3 shift valve 22 via the oil passage 434, but the port 122g is connected to the 2-3 shift valve 22 as described below.
Line pressure is supplied when the shift valve 22 is in the third gear position (up side). The line pressure booster valve with such a configuration differs when the 2-3 shift valve 22 is switched from the 2nd gear position (down side) to the 3rd gear position, and vice versa when it is switched from the 3rd gear position to the 2nd gear position. , their behavior is different. 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 21 of the line pressure booster valve 16
6 is pressed by a spring 316 and is in the position shown in the upper half of the figure (1-2 shift valve 20
When the engine is in the second speed position, line pressure is supplied to port 116b, but since this port 116b is blocked by land 216b, line pressure booster valve 16 is not switched). In this state, port 116d communicates with drain port 116c. Next, when the 2-3 shift valve 22 is switched to the 3rd speed position, line pressure is supplied to the oil passage 434 as described later. Oil road 434
The line pressure of port 116a and spool 21
It acts on the left end surface of the spool 216 through the hole 216d of No. 6, and moves the spool 216 rightward 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, port 116b
and the hole 216d of the spool 216 (the port 116a is closed by the land 216a), and the pressure of the oil passage 432 acts on the left end of the spool 216. Therefore, 2-3 shift valve 2
2 is switched to the second 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 position in the figure, if the manual valve 4 is not in the or position, the port 104 of the manual valve 4
Since e is a drain port, oil passage 42
8 is port 116d, port 116e, oil passage 4
The oil is drained to port 104e through 14.
However, when the manual valve 4 is in the or position, line pressure is supplied to the oil passage 414, so the oil passage 4
28 is supplied with line pressure. The line pressure of the oil passage 428 is supplied to the port 112d of the pressure modifier valve 12 via the shuttle valve 506, and acts to increase the line pressure as described above. Therefore, when driving in 3rd gear, if you switch the manual valve 4 to 2nd gear and use engine braking to force 2nd gear, the line pressure will increase, so you can quickly shift gears and use engine braking effectively. can do. In addition, 1-
When the 2nd shift valve 20 is in the 1st gear position, the oil passage 43
Since the hydraulic pressure No. 2 is discharged, 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 attached so as to rotate together with the output shaft O of the automatic transmission, and the line pressure supplied from the oil passage 412 (the line pressure supplied when the manual valve 4 is in the D or position ) to adjust the pressure,
Hydraulic pressure (governor pressure) corresponding to the vehicle speed is supplied to the oil passage 430. The governor pressure has characteristics as shown in FIG. 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 apply chamber S/A of the brake B2. The port 120d is connected to the shuttle valve 5 via a no-way 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 apply 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 122d 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 obtained by subtracting the area difference between land 222d and land 222d (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, causing spool 222 to move upward. It is set so that it is pressed. Port 122f, which is provided with orifice 616 at its inlet, 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. It's like this. 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 according to 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. Port 124c is connected to clutch C3 via oil passage 442. This port 124c is connected to the oil passage 444 when the spool 224 is in the up position.
Brake B ₂ servo release chamber S/R through
The port 124d is connected to the port 124d. Port 124d communicates with port 124e when spool 224 is in the down position. Port 124e
is connected to clutch C ₂ via oil passage 434 . The port 124f is connected to the 2-
The port 124g is connected to the 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 12
4k is connected to an oil passage 430 which is a governor pressure circuit, and is connected to the above-mentioned 1-2 shift valve 20 and 2.
-3 Similar to the shift valve 22, the spool 224
When the spool 224 is in the down position, the governor pressure acts on the area of the land 224c, and when the spool 224 is in the up position, the governor pressure acts on the area of the land 224d, pushing the spool 224 upward. 3 of such configurations
The -4 shift valve 24 controls the supply of pressure oil to the clutch _C3 and the servo release chamber S/R according to 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 led 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, causing the spool 226 to move downward in the figure. I'm pushing.
The port 126d is connected to the oil passage 446, and when the spool 226 is in the down position, the port 126d is connected to the oil passage 446.
6e, and when the spool 226 is in the up position, it communicates with the port 126c. Port 126f is connected to clutch _C2 via oil passage 434.
2-4 timing valve 26 with such a configuration
This functions to supply pressure oil to clutch C ₂ and discharge pressure oil from clutch C ₃ at predetermined timing during 2-4 gear shifting, 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 having a to c shape and fitted into the valve hole 128 so as to be movable in the axial direction, and a spring 328 when the spool 228 is pushed upward in the figure. 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
Valve hole 130 having a to e and 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. Both ports 130c and 130d are connected to the oil passage 442, but the port 130c is connected to a check valve 752 and an orifice 652 provided in the middle of the oil passage 442 (both are provided in parallel).
upstream side (port 12 of 3-4 shift valve 24)
Connected to the side closer to 4c, 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 c 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. An oil passage 430 is provided in the port 132a.
Governor pressure is supplied from the spool 232.
is receiving a 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 provided in the middle of the oil passage 434.
and the upstream side (the side that directly communicates with the port 122g of the 2-3 shift valve 22) of the orifice 654 (both are provided in parallel),
Port 132d is on the downstream side (3-4 shift valve 2
(the side that directly communicates with port 124e of No. 4). 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 consists of. Ports 134a and 134b
is the drain port. The port 134d is connected to an oil passage 416 (an oil passage to which line pressure is supplied when the manual valve 4 is in the position),
Further, 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 1-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
A spool 236 having 36a and 36b and fitted into the valve hole 136 so as to be movable in the axial direction, and a spring 33 that pushes the spool 236 to the left in the figure.
It consists of 6. Ports 136d and 136
e is a drain port. Port 136b is connected to oil passage 406 (port 102 of regulator valve 2).
The ports 136a and 136c are connected to the torque converter T/C via an oil path 450. An orifice 624 is provided at the entrance of the port 136a. The torque converter pressure reducing valve 36 having such a configuration has the port 136b as a high pressure port, the port 136d as a drain port, and performs a pressure regulating function, and the port 136a as a drain port.
so that the hydraulic pressure of the spring 336 balances 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. 4-3 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, allowing the 4-3 gear shift to be performed smoothly, and also for manual control. To reduce shock when a valve 4 is moved from N position to 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. Switch SW
is off, the 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. Even if the oil is drained, it will not affect the line pressure). When the switch SW is turned on, the opening 409a is closed by the rod 42a, so the oil passage 409 has the same pressure as the oil passage 402 (ie, line pressure). By this,
As will be described later, the 3-4 shift valve 24 is held in the down position to prevent it from going into 4th gear (overdrive). Orifices 62 are installed at the entrances of clutch C1, clutch C3, and servo apply chamber S/A, respectively.
6, 628 and 630 are provided. Next, the general operation of the hydraulic control device having the above configuration will be explained. First, the line pressure regulated by the regulator valve 2 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 cutback pressure have the characteristics shown in Figures 4 and 5, respectively, the obtained line pressure is expressed based on the throttle opening as shown in Figure 7. Become. However, when driving in second gear with the manual valve 4 in the D position or with the manual valve 4 in the D position, the pressure modifier pressure is constant and the cutback pressure is 0, so the line pressure remains regardless of the throttle pressure and governor pressure. (In other words, under the above conditions, line pressure is generated in the oil passage 428 by the action of the line pressure booster valve 16, so the line pressure in the oil passage 428 is changed to the oil passage 426 by switching the shuttle valve 506. It gets through.
For this reason, the pressure modifier valve 12
Line pressure is supplied to the port 112d, and the pressure modifier valve 12 generates a constant pressure in the oil passage 411 as described above. Also, the line pressure of the oil passage 428 is supplied to the port 114e of the cutback valve 14, so the spool 214 is pushed to the left in the figure, the spool 215 is pushed to the right in the figure, and the oil passage 410 is connected to the drain port 114b. The oil pressure becomes 0. ). In addition, N ₀ in Fig. 7 is the rotation speed of the output shaft O,
The line pressure varies depending on the vehicle speed as shown in the diagram. Furthermore, the line pressure is shown in FIG. 8 based on the vehicle speed. Next, the operation at each position of the manual valve 4 will be explained. When manual valve 4 is in the N position,
Ports 104b, 104d, 104e and 104
Since line pressure is not supplied to any of the clutches and the brakes are drain ports, no hydraulic pressure is supplied to any of the clutches and brakes, and the automatic transmission is in a neutral state with no power 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 1-2 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 reaches clutch C3 through orifices 658 and 628, causing it to engage. This allows the one-way clutch to be activated as described above.
A state of first forward speed is achieved through cooperation with OWC. Note that the oil passage 442 also communicates with the chamber 140b of the 4-3 accumulator 40, so the chamber 14
Line pressure is supplied to 0b, and chamber 1 is
The piston 240 of the 4-3 accumulator 40, which has been pushed down in the figure by the line pressure acting on the piston 40a, is slowly moved upward by the force of the spring 340. Therefore, the oil pressure on the downstream side of the orifice 658 will rise slowly, and the clutch C3 will be engaged with a relatively low oil pressure, reducing the shock (select shock) when switching from the N position to the D position. be done. 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 320.
The spools 220 and 221 begin to rise from the down position by overcoming the downward force due to the throttle pressure acting on the area difference between the ports 120c and the lands 220b and 220c. At that time, the land 221d of the spool 221 cuts off the port 120j, and at the same time the land 221d
1c opens the drain port 120i, the area of action of the governor pressure suddenly increases, and the spools 220 and 221 instantly rise 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 apply 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 from the oil passage 402 to the chamber 138b. Therefore, the oil pressure in the portion of the oil passage 432 downstream of the orifice 656 rises slowly, and the brake B2 operates slowly. This alleviates the shock (shift shock) when shifting from the first speed to the second speed. When the vehicle speed further increases while driving in second gear and the governor pressure reaches a certain value, the force of the governor pressure acting upward on the spool 222 of the 2-3 shift valve 22 is combined with the downward force of the spring 322 and the port 122e to lands 222b and 222c
The spool 222 overcomes the downward force due to the throttle pressure acting on the area difference between the two, 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 opens the drain port 122h, so the area of action of the governor pressure suddenly increases and the upward force increases, and at the same time, the land 222d opens the drain port 122h.
Port 122e is connected to the area difference between 22b and 222c.
The throttle pressure acting from port 122d
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). Therefore, the ports 122f and 122g communicate with each other, and the line pressure of the oil passage 432 is introduced into the oil passage 434. Oil road 434
is connected to clutch C2, so clutch C
2 is concluded. Further, the oil passage 434 communicates with a port 124e of the 3-4 shift valve 24, and this port 124e is connected to the 3-4 shift valve 24.
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 brake B2 is released. Clutches C2 and C3 are therefore engaged;
Third gear condition is achieved. In addition, as mentioned above, when shifting from 2nd speed to 3rd speed, brake B2
It is necessary to release the clutch C2 and engage the clutch C2 at the same time, and if they are not operated at the appropriate timing, a large shift shock or engine racing may occur. For this reason, the oil passage 434 from the 2-3 shift valve 22 to the clutch C2
A 2-3 timing valve 28 is provided in the middle. 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. , the upstream side and the downstream side of the oil passage 434 are connected 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, the port 122g of the 2-3 shift valve 22
A 3-2 timing valve 32, a check valve 754, and an orifice 654 are arranged in parallel in the middle of the oil passage 434 leading from the port 124e of the 3-4 shift valve 24.
Since the direction of oil flow from port 124e to port 124e matches the direction in which check valve 754 allows flow, there is no restriction in servo release chamber S/R regardless of the state of 3-2 timing valve 2. Hydraulic pressure is supplied without any 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 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 upward force increases, 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.
Although it is connected to the port 126d of the timing valve 26, 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, so the port 126d is connected to the drain. port 12
It communicates with 6c. Therefore, the hydraulic pressure in the clutch C3 and the servo release chamber S/R are both discharged, and the clutch C3 is released and the brake B2 is applied. By this, clutch C2
and brake B2 are operated to achieve the fourth speed state. 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, port 1
A 3-4 timing valve 30, a check valve 752, and an orifice 652 are provided in parallel in the middle of the oil passage 442 from 24c to port 124g. /R hydraulic pressure discharge speeds 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 1
24g bypassing orifice 652, while in the coasting state, communication between ports 124c and 124g is cut off (thus, both ports are connected via orifice 652). Therefore, in the coasting state, the oil pressure in the servo release chamber S/R gradually decreases,
The engagement of brake B2 is slightly delayed from the release of clutch C3. During this short period of time, the engine speed decreases, so the shift shock is reduced accordingly. 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 this oil pressure of the clutch C2 is also guided to the port 126f of the 2-4 timing valve 26. There is. In the second speed state, the 2-4 timing valve 26 is pushed down to the position shown in the left half of the figure by the throttle pressure introduced to the port 126b. Therefore, ports 126d and 126
The oil pressure of the clutch C3 is communicated with the oil passage 442 and the port 12 of the 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 up 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 will occur. 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 clutch C2 and clutch C3 are operated. Clutch C
When the oil pressure of 3 increases, 4-3 accumulator 4
0 is activated so that the oil pressure increases gradually. That is, the piston 240 of the 4-3 accumulator 40 is in the chamber 14 in the fourth speed state.
Since the oil pressure in 0b is discharged through the oil passage 442, it is pushed down by the line pressure in the chamber 140a, but when the 3-4 shift valve 24 is switched and oil pressure is generated in the oil passage 442, the spring 340
pushed up by the force of During this time, oil line 44
2 (that is, the oil pressure of clutch C3) rises slowly, and clutch C3 is engaged while the oil pressure is rising, clutch C3 is engaged with an appropriate pressing force and does not cause a large shift shock. When the governor pressure further decreases or the throttle pressure increases while driving in third gear, 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 3-2 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. Therefore, the hydraulic pressure acting on the servo apply 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 also passes through the shuttle valve 508 and the oil passage 440 to the 3-3 shift valve 20.
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 in the gear down state, the gear will not be shifted 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 the tight down).
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 shift and the 3-2 shift 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, 1-
The vehicle speed for second shift and 2-1 shift becomes significantly higher than in the non-kickdown state. When the relationship between the vehicle speed and the throttle opening during automatic gear shifting obtained as described above is shown in a diagram, the shift diagram is shown in FIG. 9. 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 want to drive in the fourth gear (overdrive) depending on the driving conditions, the driver can prevent the vehicle from going into the fourth gear 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 port 116d, and oil passage 428
generates line pressure. As a result, as mentioned above, the line pressure is at its highest regardless of the throttle opening, so even when the throttle opening is small, brake B2, which is a handbrake, can be operated strongly, and the second gear Shifting to and fro is performed quickly, and engine braking can be applied 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 acting on the left end of 6 in the figure 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 so, 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 guided to the first speed fixed range port 134d of the pressure reducing valve 34. This line pressure is
34c and oil passage 448 to reach port 134e, push spool 234 upward in the figure, and balance spool 234 with drain port 134b slightly open. Therefore, port 13
The oil pressure of 4E (that is, the oil pressure of oil passage 448) is
A constant value of pressure (lower than the line pressure) corresponds to the force of the spring 334. This oil passage 44
The constant pressure of 8 is led to the port 120d of the 1-2 shift valve 20 via the shuttle valve 502 and the oil passage 436, and is applied to the land 22 of the spool 221.
It acts on the upper side of 1a 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 line pressure in the oil passage 432 is discharged to the drain port 120i, and the brake B2 is released. At the same time, the ports 120d and 120e of the 1-2 shift valve 20 communicate with each other, 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 first speed (first speed in which engine braking can be applied) with clutch C3 and brake B1 activated. Note that when the governor pressure is above the above-mentioned certain value, the port 12
Since the spool 221 does not switch even if a constant pressure from the first speed fixed range pressure reducing valve 34 acts on 0d, the first speed will not be reached even if the manual valve 4 is in the position while the vehicle is running at a certain speed or higher. Engine overrun 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 brake B1. Therefore,
Clutch C1 and brake B1 are activated, and the automatic transmission is placed in reverse. As mentioned above, the present invention provides a 3-4 shift valve 24.
has been applied, and this will be briefly explained again. The 3-4 shift valve 24 includes the spool 224, the plug 225, and the spring 324 as described above. When the throttle pressure is large, the spring 324 is compressed, so the spool 224 and the plug 225 operate as one unit to switch the oil path. When the throttle pressure is small, the plug 225 is pushed upward in the figure by the spring 324, and the spool 224 and plug 225 are separated. Therefore, the spool 224 is switched depending on the magnitude relationship between the force caused by the spring 324 and the force caused by the governor pressure, and the spool 224 is switched at a constant vehicle speed regardless of the throttle pressure. When line pressure is introduced into the port 124b, the plug 225 is pushed up and the spool 224 is pushed down regardless of the values of the throttle pressure and governor pressure. Therefore, 3-4 shift valve 2
4 is always in the down position. Port 124a on which throttle pressure acts and port 124 on which line pressure (signal oil pressure for holding in the down position) acts
Since it is a separate port from port b, there is no need to use a shuttle valve to switch between throttle pressure and line pressure, and the configuration of the hydraulic circuit is simplified. In addition, in the above-mentioned embodiment, the characteristics of the line pressure and governor pressure and the pressure receiving area of the spool 224 were set so that the 3-4 shift valve is always in the down position when the line pressure is introduced into the port 124b. The pressure-receiving area where the line pressure acts to push down the spool 224, and the governor pressure which acts on the spool 224
It is also possible to increase the difference between the pressure receiving area acting in the direction of pushing down the spool 224 and prevent the spool 224 from switching to the down position even if line pressure is applied when the governor pressure is greater than a predetermined value.
In this case, even if line pressure is introduced to the port 124b, the shift from 4th gear to 3rd gear is not performed at a predetermined vehicle speed or higher, the 4th gear state is maintained, and after the vehicle speed has decreased to a predetermined value, the gear shift is not performed. A shift to third gear will be performed. This makes it possible to prevent the engine from overrunning due to extremely high speed shifting to third gear. In addition, the spool 22
4 is provided with hysteresis, so once a shift is made from 4th gear to 3rd gear, the 3rd gear state is maintained and the shift to 4th gear is never made. Also,
As mentioned above, at a small throttle opening, the 3-4 shift valve 24 switches at a constant vehicle speed regardless of the throttle opening (the 3-4 shift line and 4-4 shift line in FIG. 9).
(Refer to the part of the 3rd shift line where the throttle opening is 1/4 or less).
As a result, the region of large throttle opening and the region of small throttle opening can be adjusted independently.
A desired shift line can be obtained over the entire throttle opening. Moreover, the constant vehicle speed can be easily changed only by the setting force of the spring 324. As explained above, according to the present invention, there is a spool for switching oil passages to which governor pressure is applied from one end (in this embodiment, the spool 224 of the 3-4 shift valve 24), and a spool disposed at the other end of the spool. A widthwise movable plug on which throttle pressure acts in a direction opposite to governor pressure (in this embodiment, plug 2
25) and a spring (in this example, spring 324) disposed between the spool and the plug.
and a shift valve (in this example, 3-4
A down position holding signal oil pressure (line pressure output when the manual valve is in the 2 or 1 position,
(line pressure, etc. output when the overdrive inhibitor solenoid is activated) is guided, and the pressure receiving area where the down position holding signal hydraulic pressure acts on the spool is guided, and the governor pressure acts on the spool when the spool is in the up position. In addition, the spool has a structure with hysteresis so that when it is in the down position, the governor pressure receiving area is smaller than when it is in the up position, and the area of the throttle pressure receiving part of the plug is The relationship with the setting force of the spring is set so that when the throttle pressure is a predetermined value larger than the value when the throttle is fully closed, the force exerted by the throttle pressure on the plug is equal to the setting force of the spring. A downshift shift point exists even when the down position holding signal oil pressure is output, and in a high speed state higher than a predetermined speed, even if the down position holding signal oil pressure is output, the shift to the down position is not performed, and the engine The effect is that overrun can be prevented, and when the throttle pressure is below the predetermined value, the shift line is determined by the magnitude relationship between the spring setting force and the force due to the governor pressure, and at a small throttle opening the desired This provides the advantage of being able to shift gears at a constant vehicle speed.

[Brief explanation of drawings]

Figure 1 is a framework diagram of a 4-speed automatic transmission with overdrive, Figure 2 is a hydraulic circuit diagram showing the entire hydraulic control system, Figure 3 is a diagram showing throttle pressure and throttle modulate pressure characteristics, and Figure 3 is a diagram showing throttle pressure and throttle modulate pressure characteristics. Figure 4 is a diagram showing pressure modifier pressure characteristics, Figure 5 is a diagram showing cutback pressure characteristics, Figure 6 is a diagram showing governor pressure characteristics, and Figure 7 is a diagram showing line pressure characteristics. ,
FIG. 8 is a diagram showing line pressure characteristics, and FIG. 9 is a diagram showing shift patterns. 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, C
1, C2, C3...Clutch, B1, B2...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, 10
2,104,106,108,110,112,
114, 116, 120, 122, 124, 12
6,128,130,132,134,136...
...Valve holes, 102a-j, 104a-f, 10
6a-f, 108a-e, 110a-e, 112
a~e, 114a~g, 116a~f, 120a
~k, 122a-j, 124a-k, 1266a
~e, 130a~e, 132a~e, 134a~
e, 136a-e...Port, 138, 140...
...Cylinder hole, 202, 203, 204, 20
6,210,212,214,215,216,
220, 221, 222, 224, 226, 22
8,230,232,234,236...Spool, 202a-d, 203a-b, 204a-
b, 206a-c, 208a, 210a-c, 2
12a-b, 214a-c, 215a-b, 21
6a-c, 220a-c, 221a-d, 222
a~e, 224a~d, 226a~c, 228a
~c, 230a~c, 232a~c, 234a~
b, 236a-d...Land, 207...Plunger, 208...Sleeve, 209...Plug,
223...Plug, 225...Plug, 238,
240...Piston, 252...Sleeve, 25
2a-c...port, 254...spring seat, 302, 306, 307, 308, 310,
312, 316, 320, 322, 324, 32
8,330,332,334,336,338,
340... Spring, 402, 404, 40
6,408,409,410,411,412,
414, 416, 418, 420, 422, 42
4,426,428,430,432,434,
436, 438, 440, 442, 444, 44
6,448,450...Oil road, 502,504,
506,508...Shuttle valve, 602,6
04,606,608,610,612,61
4,616,618,620,622,624,
626, 628, 630, 650, 652, 65
4,656,658... Orifice, 750,7
52,754,756,758...Check valve.

Claims (1)

[Scope of Claims] 1: an oil passage switching spool to which governor pressure is applied from one end; an axially movable plug disposed at the other end of the spool and to which throttle pressure is applied in a direction opposite to the governor pressure; a spring disposed between the spool and the plug; a port that guides a down position holding signal hydraulic pressure between the spool and the plug;
In a shift valve for changing gears of an automatic transmission equipped with a shift valve, the pressure receiving area of the spool on which the down position holding signal oil pressure acts is smaller than the pressure receiving area of the spool on which governor pressure acts when the spool is in the up position. The spool has a hysteresis structure in which the governor pressure receiving area is smaller when it is in the down position than when it is in the up position, and the area of the throttle pressure receiving part of the plug and the setting force of the spring mentioned above are The relationship is characterized in that when the throttle pressure is a predetermined value greater than the value when the throttle is fully closed, the force exerted on the plug by the throttle pressure is set to be equal to the set force of the spring. Automatic transmission shift valve. 2. The shift valve is a valve that makes the automatic transmission have the smallest reduction ratio in its up position, and the down position holding signal oil pressure is the oil pressure that is output when the manual valve is in a forward travel position other than the D position. , the automatic transmission according to claim 1, which is the hydraulic pressure output when the gear is turned down, or the hydraulic pressure generated by an electric device that is operated when it is desired to prevent the reduction ratio from reaching the lowest state. machine shift valve.