JPH01112061A - Hydraulic shifting device for automatic speed change gear - Google Patents

Abstract

PURPOSE:To cause a single shift valve to suffice for operation of a device and to enable increase of the number of steps of a small automatic speed change gear, by a method wherein, during gear shift between a 2-step and a 3-step and between a 3-step and a 4-step, the engaging and disengaging timings of a plurality of frictional engaging devices are controlled by a shifting means. CONSTITUTION:During gear shift, for example, from 2-step to 3-step, a shift valve 7 is shifted with the aid of a motor, a line pressure is introduced to oil passages 103, 110, 111 to move rightward first timing valve 8. The line pressure is fed to a hydraulic servo C-2 through a 2-way valve 19 with an orifice, and is also fed to a hydraulic servo B-1 to release a brake. A second timing valve 9 is shifted in a delay by a given time by means of a 2-way valve 18 with an orifice to feed a line pressure to a hydraulic servo C-O. Thus, a clutch C2 is first engaged to release a brake B1, and thereafter a clutch C0 is engaged to prevent the occurrence of gear shift shock. This constitution causes a single shift valve to suffice for operation of a device, and eliminates a solenoid valve, resulting in the possibility to increase the number of steps of a small automatic speed change gear with a limited space.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic switching device in an automatic transmission for a vehicle.

[Conventional technology]

In general, automatic transmissions for vehicles include a planetary gear mechanism and a plurality of friction engagement devices such as clutches or brakes.
By changing the engagement states of these frictional engagement devices in various ways, selectively connecting some rotating elements in the planetary gear mechanism to each other, or braking the rotation of certain rotating elements, the current driving state of the vehicle can be adjusted. The system is configured to automatically achieve the optimum gear position for the vehicle. for that,
Switching control of the frictional engagement device is normally performed by a hydraulic circuit, and is performed by manually operating a manual lever in the vehicle interior and positioning a manual valve connected by links and cables. Hydraulic pressure is supplied to and discharged from the engagement device using a 1-2 shift valve,
This is carried out by multiple shift valves such as 2-3 shift valves and 3-4 shift valves, and on the other hand, vehicle speed and throttle opening signals corresponding to the driving state of the vehicle are input to an electronic control circuit and stored in advance. Based on the result of this judgment, a solenoid valve provided in the hydraulic circuit is actuated to control switching of the gear shift valve to achieve the optimum gear position according to the operating condition of the vehicle. It looks like this.

In addition, a control device for an automatic transmission that eliminates the manual lever described above and can control gear changes with a single shift valve operated by a push button switch has been disclosed in Japanese Patent Application Laid-Open No. 61-20197.
This is proposed in Publication No. 3 or Japanese Patent Application Laid-Open No. 61-206859.

FIG. 9 shows a pulp control device proposed in the above-mentioned Japanese Patent Laid-Open No. 61-201973.

The figure shows the parking range P, where only the second solenoid valve 215b is turned on and drains, and the second plunger 211b protrudes due to the biasing force of the spring 212 and comes into contact with the first valley part A of the cam part 210. There is. In this state, the line pressure boat 207 is blocked, and
The R port and the D, 2, and L ports communicate with drain ports 206 and 206', respectively.

Then, when the driver presses the push button switch,
While turning off the second solenoid valve 215b, the first solenoid valve 215b is turned off.
When the solenoid valve 215a is turned on, the first plunger 211a comes into contact with the slope of the cam portion 210, moves the spool 205 to the right, and engages with the second valley opening.

Next, when the first solenoid valve 215a is turned off and the third solenoid valve 215c is turned on, the third plunger 211c comes into contact with the slope of the cam part 210 and moves the spool 205 further to the right to move the spool 205 to the first valley. Engage with part A. As a result, the line pressure 207
communicates with the R port and becomes reverse range.

Thereafter, by sequentially operating the solenoid pulps 215a to 215c, the plungers 211a to 211c are projected, and the spool 205 is moved stepwise to the right, thereby closing the line pressure boat 2-07 in the N range. , a D range that connects the line pressure port 207 to the D/2/L boat, and a D range that connects the line pressure port 207 to the D/2/L boat.
・2 ranges connected to L port and 2・L boat,
An L range is obtained in which the line pressure port 207 is communicated with the D/2/L port, the 2/L port, and the L boat.

[Problem that the invention seeks to solve]

In the case of recent small vehicles, especially front-wheel drive light vehicles, there is the issue of having to design automatic transmissions that are small and have multiple shift stages of 3 to 4, making mechanical parts such as gear trains smaller. However, the size of the hydraulic control unit that controls the shift gears is related to the number of shift gears, regardless of the size of the gear train, so it is necessary to reduce the size of the hydraulic control unit. It is difficult.

However, in the conventional automatic transmissions for vehicles that use manual levers, in recent years it has become necessary to install various information devices such as road surface condition determination, traffic information, and navigation systems in the vehicle interior. ,
The manual lever has a problem in that it occupies a large area in the vehicle interior. In addition, since the manual lever and manual pulp are linked together, the connection method,
There are restrictions on size, operating force, mounting position, etc., and there are problems in that the space inside the vehicle cannot be used effectively and the parts used for link connection are complicated.

In addition, it incorporates a manual valve that changes the gear range in conjunction with the shift lever, and a shift valve that switches depending on the throttle opening and vehicle speed, so when increasing the number of gears, As the number of shift valves required increases, the valve body becomes larger, the hydraulic circuit becomes more complex, and the weight, volume, and cost increase, creating a major obstacle to miniaturization and cost reduction of automatic transmissions. There is.

Furthermore, in the system shown in Fig. 9 above, when increasing the number of gears, it is necessary to provide a corresponding number of solenoid pulps, which complicates the structure and increases weight, volume, and cost. have. Furthermore, since the solenoid is constantly energized and the solenoid valve is constantly operated, there are problems in that the durability of the solenoid device is reduced, power consumption increases, and it is necessary to increase the power generation capacity of the alternator. Furthermore, if the solenoid is inoperable due to a disconnection or a malfunction in the electrical circuit, the oil pressure will fluctuate and the shift position will change unexpectedly, so it is necessary to provide a special fail-safe function in the electronic control circuit to prevent this. I have a problem.

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and aims to provide a hydraulic switching device for an automatic transmission that can simplify the configuration of a hydraulic circuit and make effective use of space within a vehicle interior.

[Means for solving problems]

To this end, the hydraulic switching device in the automatic transmission of the present invention includes a plurality of frictional engagement devices that selectively connect some rotating elements in a planetary gear mechanism to each other, and a hydraulic circuit that switches and controls the frictional engagement devices. In the automatic transmission for a vehicle, the hydraulic circuit includes a regulator pulp that generates line pressure, one shift pulp that selectively switches the line pressure to the frictional engagement device, and the shift pulp. The present invention is characterized in that it has a motor that switches and drives the motor, and a switching means that controls the timing of engagement and disengagement of the plurality of frictional engagement devices during shifting between 2nd and 3rd speeds and between 3rd and 4th speeds.

[Action and effect of the invention]

In the present invention, for example, as shown in FIG. 1, when shifting from second to third speed, the motor switches the shift pulp 7 to the position shown in FIG. 111 is also communicated with line pressure, and other oil passages leading in and out of the shift pulp 7 are drained. Therefore, line pressure acts on the left side of the first timing valve 8,
Since the pulp 8 is switched to the lower side in the figure, the line pressure is applied to the oil passage 109, the pulp 8, and the two-way valve with orifice 19.
It is supplied to the hydraulic servo C-2 via the hydraulic servo C-2, and also releases the re-brake on the lower side of the second spool 16 of the hydraulic servo B-1. Moreover, since pressure acts on the spring side of the second timing valve 9 via the oil passage 112 and the two-way valve with orifice 18, the pulp 9 is switched upward in the figure after a predetermined time delay, and the oil passage 109 , the line pressure is supplied to the hydraulic servo C-0 via the pulp 9. Therefore, clutch C2 is first engaged, brake B1 is released, and then clutch C0 is engaged, thereby preventing shift shock.

Furthermore, when shifting from 3rd gear to 2nd gear, hydraulic servo C-2
Since the pulp 9 is drained with a delay through the orifice-equipped two-way valve 19, the clutch C0 is first released, then the clutch C2 is released and the brake B is activated.

Therefore, according to the present invention, the following effects are achieved.

(a) Since the manual lever has been eliminated, space inside the vehicle can be used more effectively.

(b) Only one shift pulp is required, and there is no need for a solenoid valve to operate it, so the pulp body becomes compact and can be installed in small transmissions for small cars. Further, it becomes possible to control multi-stages of a small automatic transmission.

(c) In the event of a failure in the electric circuit or a break in the wiring, the motor will stop and the shift stage will remain the same, making it safe without the need for special measures.

(d) Since it is necessary to operate the motor only when switching gears, the durability of the device is improved and power consumption is significantly reduced.

(e) Since the main switching pulp is forcibly operated by motor drive, pulp stick is less likely to occur.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows one of the hydraulic switching devices in the automatic transmission of the present invention.
2 is a schematic diagram showing an example of an automatic transmission to which the present invention is applied; FIG. 3 is a diagram for explaining the operation of FIGS. 1 and 2; 4 is a sectional view showing the switching mechanism of the shift valve in FIG. 1, FIG. 5 is a sectional view showing the position of the shift valve in the shift range,
FIG. 6 is a hydraulic circuit diagram showing another embodiment of the hydraulic switching device in the automatic transmission of the present invention, FIG. 7 is a sectional view showing the position of the shift pulp in the shift range in FIG. 6,
FIG. 8 is a diagram for explaining the operation of FIG. 6.

First, an automatic transmission to which the present invention is applied will be explained with reference to FIG. 2. The torque converter section A consists of a torque converter 30 and a lock amplifier clutch 31, and converts engine rotation from a crankshaft 32 to oil in the torque converter 30. The signal is transmitted to the input shaft 33 in the automatic transmission mechanism section B through a mechanical connection by the flow or lock amplifier clutch 31.

The 4-speed automatic transmission mechanism part B has a second clutch c2, a first brake B11, a planetary gear unit 34, a first clutch c1, and a third clutch C0 arranged in order from the engine output side on the outer periphery of the input shaft 33. Further, a hollow shaft 35 is rotatably fitted onto the outer periphery of the input shaft 33.

The planetary gear unit 34 is of a dual type, and has a carrier CR that supports a sun gear S formed on a hollow shaft 35, a small ring gear R1, and a long pinion P1 that meshes with these gears.
R also supports a short pinion P2 that meshes with a long pinion P3 and a large ring gear R2.

On the other hand, the second clutch c2 has a hollow shaft 35 and an input shaft 33.
A first brake B, which is a band brake, can be moved into and out of contact with the outer periphery of the second clutch C2.

Further, a counter drive gear 36 is disposed approximately in the center of the automatic transmission mechanism section B, and the inner circumference of the drive gear 3G is spline-coupled to the carrier CR. A one-way clutch F is spline-coupled, and a clutch-type second brake B2 is interposed between the outer periphery of the large ring gear R2 and the axle housing. Furthermore, the first clutch CI is interposed between the input shaft 33 and the outer periphery of the small ring gear R5 of the planetary gear unit 34, and the third clutch CO is interposed between the input shaft 33
and the outer periphery of the large ring gear R2 of the planetary gear unit 34.

The automatic transmission with the above configuration has a planetary gear unit 34.
However, since the carrier CR and sun gear S are integrally configured, the size can be reduced, and since the counter drive gear 36 is located approximately in the center of the automatic transmission mechanism, the transmission path is reciprocating. Therefore, it is possible to achieve compactness in the axial direction.

Next, the operation of the automatic transmission having the above structure will be explained with reference to the operation table shown in FIG.

First, in the speed state, the first clutch CI is engaged. Then, the rotation of the input shaft 33 is transmitted to the small ring gear R3 via the first clutch CI, and at this time, since the rotation of the large ring gear R2 is prevented by the one-way clutch F1, it causes the sun gear S to idle in the opposite direction. Meanwhile, the common carrier CR is rotated in the forward direction at a significantly reduced speed, and the rotation is taken out from the counter drive gear 36.

In the second speed state, in addition to the engagement of the first clutch C1, the first brake B is activated, and the rotation of the sun gear S is stopped by the first brake B1, so that the rotation of the sun gear S is stopped by the first brake B1. The rotation is made by rotating the carrier CR at a reduced speed in the positive direction while causing the large ring gear R2 to idle in the positive direction.
This rotation is taken out from counter drive gear 36 as second speed.

In the third speed state, in addition to the engagement of the first clutch C1, the third
Clutch C0 and second clutch c2 are engaged, and the rotation of input shaft 33 is transmitted to small ring gear R,
At the same time, the transmission is transmitted to the large ring gear R2 via the clutch Co, and each element of the planetary gear unit 34 rotates as a unit.Therefore, the carrier CR also rotates as a unit, and the signal is transmitted from the counter drive gear 36 to the input shaft 33. The same speed rotation is extracted. In addition, in the 3rd speed state shown in Fig. 3,
This shows that hydraulic pressure is being supplied to brake B, but as will be explained later, clutch C is not connected to the brake B1 release mechanism.
Since the two pressures are in communication, the brake B1 is not engaged and integral rotation is possible.

In addition, in the 4th speed state, when the first clutch CI is released and the third clutch C0 and the first brake B1 are activated, the rotation of the human power shaft 33 is transmitted to the large ring gear R8 via the clutch C0, At this time, since the sun gear S is stopped by the brake B1, the carrier CR rotates at high speed while causing the small ring gear R+ to accelerate and idle, and this high speed rotation acts as an overdrive to the counter drive gear 3.
6.

In the reverse range, the second clutch C2 and the second brake B are engaged, and the rotation of the input shaft 33 is transmitted to the sun gear S via the second clutch C2, and at this time, the large ring gear nt is Since it is fixed by the braking of the brake B2, the carrier CR is also reversed while the small ring gear R6 is being reversed, and the reverse rotation of the carrier CR is taken out from the counter drive gear 36.

Furthermore, in the l-speed state during coasting, the one-way clutch F is in a free state, but the first clutch C1
In addition to the engagement of the second brake B2, the second brake B2 is engaged, and the large ring gear R2 is fixed by the brake Bi, so that the first gear shift state is maintained and the engine brake is effectively operated.

Next, one embodiment of a hydraulic switching device for an automatic transmission according to the present invention will be described with reference to FIG. Its configuration is: oil pump 1, primary regulator valve 2, secondary regulator valve 3, lock amplifier control valve 5,
Shift valve 7, first to fourth timing valves 8 to 1
1, Brake B+, Bz, Clutch C+, C0,
Hydraulic servo B-1, B- for engaging and releasing c.
2, C-1, c-o, C-2 and d, consisting of numerous one-way valves and orifices. In the figure, ■, ■, ■, ■ displayed on the left side of the first to fourth timing valves 8 to 11 indicate the gear stage when each timing valve is fixed to the upper or lower side in the figure. ing.

The brake B1 is of a type that uses a band brake to stop rotation, and the hydraulic servo B-1 is connected to a first spool 15 attached via a spring to a fixed circle at3 fixed in the cylinder 12, and Spool 15
It consists of a second spool 16 that is fitted into the interior and urged upward by a spring, and a piston 17 that is attached to the spool 16 and operates the band brake. Above the first spool 15 is an oil pump. Hydraulic pressure is supplied from the shift valve 7 to the upper part of the second spool 16, and hydraulic pressure from the hydraulic servo C-2 is supplied to the lower part of the second spool 16. As a result, when line pressure is supplied from the shift valve 7, the second spool 16 and piston 17 move down as shown in the figure, operating the brake B, but at the same time, hydraulic pressure is supplied to the hydraulic servo C-2. Second spool 16 and piston 1
7 will rise in the figure, and brake B will be released.

FIG. 4 shows the switching mechanism of the shift valve 7.

A shift valve 7 is disposed within a cylinder 21 formed in a valve body 20. The cyst valve 7 includes:
Large diameter lands 21a, 21b, 21c and small diameter lands 22a, 22b are formed. On the other hand, a linear motor 23 is arranged at the opening of the cylinder 21 of the valve body 20. The linear motor 23 has a rotor 25 rotated by a well-known electromagnetic coil 24, and the rotor 25 is supported by a bearing 26. A sliding shaft 2G is screwed to the inner periphery of the rotor 25, and a fixing ring 27 is attached to the center of the sliding shaft 26. It is screwed to the part. The other end of the sliding shaft 26 is coupled to the shift valve 7 through a pin, so that the rotation of the rotor 25 causes the sliding shaft 26 and the shift valve 7 to slide from side to side in the figure. Note that as the motor 23, a stepping motor, an ultrasonic motor, or the like may be used.

FIG. 5 shows the state of line pressure supply and drain when the position of the shift valve 7 is changed by the linear motor 23. (a) to (h) are R range, P-N range, engine brake 1st gear, 2nd gear, and 3rd gear, respectively.
These are the states of each gear stage: 1st, 4th, and 4th lockup.

Next, the operation of the hydraulic switching device in the automatic transmission configured as described above will be explained.

The oil pressurized by the oil pump 1 is sent to the lock amplifier control pulp 5 and the hydraulic servo B-1 via the oil path 101, and is also supplied to the primary regulator pulp 2 where it is regulated to line pressure. The oil is supplied to the shift valve 7 and the first and second timing pulps 8.9 through the oil passage 102, and the remaining oil is supplied to the secondary regulator valve 3, and the secondary pressure regulated by the pulp 3 is supplied to the lubrication system and The lock-up control pulp 5 is supplied.

The line pressure supplied to the shift valve 7 operates as follows depending on the position of the shift range shown in FIG.

At the first speed, the shift valve 7 is in the position shown in FIG. 5(d), allowing line pressure to be communicated only to the oil passage 103, and all other oil passages leading in and out of the shift valve 7 are drained.

At this time, since the third timing pulp 10 is fixed to the upper side in the figure by a spring, the third timing pulp 10 and the oil path 1
Line pressure is supplied to the hydraulic servo C-1 via 05.

At this time, the pressures of the hydraulic servos B-2 and C-2 are drained through the oil passages 106 and 107 and the shift valve 7, respectively. Further, line pressure enters the left side of the second timing pulp through the oil passage 109 and is fixed at the lower side in the figure, so the pressure of the hydraulic servo c-o is drained from the opening X of the valve 9. In addition, the second spool 1 of the hydraulic servo B-1
No line pressure is supplied to the upper side of 6. Therefore, a first speed state is obtained. Note that the first timing pulp 8 is fixed at the upper side in the figure by a spring, and the fourth timing valve 11 is fixed at the lower side in the figure because line pressure enters the left side of the valve from the oil passage 105.

From the 1st speed to the 2nd speed, the shift valve 7 is switched to the position shown in FIG. Ru. Therefore, line pressure is supplied to the upper side of the second spool 16 of the hydraulic servo B-1 through the oil passage 110, and the second speed state is established. Note that the other hydraulic servo and timing valve states are the same as in the first gear.

When shifting from 2nd speed to 3rd speed, the shift valve 7 is in the position shown in FIG.
11 is also communicated with line pressure, and other oil passages leading in and out of the shift valve 7 are drained. Therefore, line pressure acts on the left side of the first timing valve 8, and this valve 8
is switched to the lower side in the figure, so the line pressure is
, is supplied to the hydraulic servo C-2 via the valve 8 and the orifice-equipped two-way valve 19, and also enters the lower side of the second spool 1G of the hydraulic servo B-1 to release the brake.

Further, since pressure acts on the spring side of the second timing pulp 9 via the oil passage 112 and the two-way valve with orifice 18, the pulp 9 is switched to the upper side in the figure after a predetermined time delay, and the oil passage 109 , hydraulic servo c via valve 9
-o is supplied with line pressure. Therefore, first clutch c
2 is engaged and after brake B is released, clutch C0
is engaged, thereby preventing shift shock.

Furthermore, when shifting from 3rd gear to 2nd gear, hydraulic servo c-2
Since the pressure of the pulp 9 is drained with a delay through the orifice-equipped two-way valve 19, the clutch C0 is first released, and then the clutch c2 is released and the brake B is activated.

When shifting from 3rd gear to 4th gear, the shift valve 7 is in the position shown in FIG.
Other oil passages leading to and from the area will be drained. Therefore,
Since pressure acts on the left side of the third timing pulp 10 and the valve 10 is switched downward in the figure, the hydraulic servo C-
The pressure of t is drained through the oil B105 and the opening X of the valve 10. Further, since the pressure from the oil passage 105 no longer acts on the fourth timing valve 11, the fourth timing valve 11
is switched to the upper side in the figure, the line pressure acts on the spring side of the first timing valve via the oil passage 114 and the oil passage 115 of the valve 11, and the valve 8 is switched to the upper side in the figure after a predetermined time delay, The pressure of the hydraulic servo C-2 is drained from the opening X of the first timing valve 8. Therefore, first, clutch CI is released, and then clutch C8 is released and brake B is operated, so that shift shock is prevented. Note that when shifting from 4th gear to 3rd gear, line pressure no longer acts on the oil passage 114, but the third timing valve 10 is switched upward after a predetermined time delay by the orifice 20, so the clutch C2 is first engaged. After brake B is released, clutch C1 is engaged.

When the 4th gear rotation is up, the shift valve 7 moves as shown in Fig. 5 (h
), oil line 103.1101111.114
In addition to this, line pressure is also communicated to the oil passage 116, and other oil passages leading in and out of the shift valve 7 are drained. Therefore, pressure acts above the lock-up control valve, fixing the valve to the left in the figure and supplying secondary pressure to the lock-up clutch.

In addition, in the R range, P-N range, and engine brake l speed, the shift valve 7 operates as shown in Fig. 5 (a), (b), and (c).
), and the hydraulic servo is switched as shown in the operation table of FIG. 3, which is obvious, so the explanation will be omitted.

Next, other embodiments of the present invention will be explained with reference to FIGS. 6 to 8. This embodiment differs from the above embodiments in the following points:
Instead of reducing the number of timing valves from four to two, the number of oil passages going in and out of the shift pulp was increased, and a gear change range as shown in FIG. 8 was provided. That is, 2.5 speed and 3.5 speed change ranges are provided.

Although its operation is similar to that of the above embodiment, only the shift from 3rd speed to 4th speed will be described.

At the third speed, the shift valve 7 is in the position shown in FIG. 7(g), and the line pressure is communicated to the oil passages 121, 122, 123, and 124, and the other oil passages leading in and out of the shift pulp 7 are drained. Therefore, line pressure is acting on the opposite side of the spring of the first switching valve 51 via the oil passage 121, so the valve 51 is fixed at the lower position in the figure, and the second switching valve 51 is fixed at the lower position in the figure. Because line pressure is acting on the opposite side of the switching pulp 52 from the spring through the oil passage 123,
The valve 52 is fixed in the lower position in the figure. Therefore, line pressure is supplied to the hydraulic servos C-01C-1 and C-2, the hydraulic servo B-1 enters the brake release state, and the hydraulic servo B-2 is drained, resulting in the third speed state.

When shifting from 3rd speed to 3.5th speed, as shown in FIG. 7(h), line pressure is also supplied to the oil passage 125, pressure acts on the spring side of the first switching pulp 51, and the valve 51
is switched to the upper side in the figure.

Therefore, the pressure of the hydraulic servo C-1 is applied to the opening X of the valve 51.
It is drained from.

When shifting from 3.5 speed to 4 speed, as shown in FIG. 7(j), line pressure is also supplied to the oil passage 126, pressure acts on the spring side of the second switching pulp 52, and the valve 51
is switched to the upper side in the figure.

Therefore, the pressure of the hydraulic servo C-2 is drained from the three-way valve with orifice 53, the second switching pulp 52, the oil passage 127, and the opening X of the first switching pulp 51.

Therefore, similarly to the embodiment shown in FIG. 1, shifting from 2nd to 3rd speed involves releasing B and C! 00 is engaged after the engagement of 0 is carried out at the same time, and for shifting from 3rd speed to 2nd speed, after C0 is released, the engagement of B and the release of 02 are carried out at the same time.

Also, when shifting from 3rd to 4th speed, release C1 and then press B.
1 is held and 02 is released at the same time, and shifting from 4th speed to 3rd speed is possible by simultaneously releasing B and engaging C1, and then engaging C5.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible.

For example, in the above embodiment, 'L1' is applied to a 4-speed automatic transmission, but it is of course applicable to a 3-speed or 5-speed automatic transmission.

[Brief explanation of the drawing]

FIG. 1 shows one of the hydraulic switching devices in the automatic transmission of the present invention.
2 is a schematic diagram showing an example of an automatic transmission to which the present invention is applied; FIG. 3 is a diagram for explaining the operation of FIGS. 1 and 2; 4 is a sectional view showing the switching mechanism of the shift valve in FIG. 1, FIG. 5 is a sectional view showing the position of the shift valve in the shift range,
FIG. 6 is a hydraulic circuit diagram showing another embodiment of the hydraulic switching device in an automatic transmission of the present invention, FIG. 7 is a sectional view showing the position of the shift valve in the shift range in FIG. 6, and FIG. 6 is a diagram for explaining the operation of FIG. 6, and FIG. 9 is a diagram for explaining a hydraulic switching device in a conventional automatic transmission. 2...Regulator valve, 7...Shift valve,
8-11...timing valve, 23...motor,
51.52...Switching valve. Figure 2 Figure 3 C2 A (JIC Yosu square gear missing, Figure 5 (A) Figure 5 (0) Figure 7 (A) Figure 7 (B) Figure 8 O heartbreak x release・ C2 light healing 11 color ￥ direction Riko Figure 9

Claims (3)

[Claims] (1) A vehicle automatic transmission comprising a plurality of frictional engagement devices that selectively connect some rotating elements of a planetary gear mechanism to each other, and a hydraulic circuit that switches and controls the frictional engagement devices, The hydraulic circuit includes a regulator valve that generates line pressure, a shift valve that selectively switches the line pressure to the frictional engagement device, a motor that switches and drives the shift valve, and a 2nd-3rd gear. A hydraulic switching device for an automatic transmission, comprising a switching means for controlling the timing of engagement and release of the plurality of frictional engagement devices during shifting between speeds and between third and fourth speeds. (2) The hydraulic switching device for an automatic transmission according to claim 1, wherein the switching means is a plurality of timing valves provided between a shift valve and a frictional engagement device. (3) The above switching means is a two-speed switch formed in a shift valve.
The hydraulic switching device for an automatic transmission according to claim 1, characterized in that the hydraulic switching device is an oil passage and a switching valve for an intermediate shift range between 3rd speed and between 3rd and 4th speeds.