JPH0510430A - Hydraulic circuit for automatic transmission - Google Patents

Abstract

PURPOSE:To simplify the structure of the hydraulic circuit of an automatic transmission formed in such a way as to perform operating pressure regulating and supply/discharge timing control to plural friction elements element by element. CONSTITUTION:In regard to two sets of friction elements 44, 45 and 41, 43 to which oil pressure is not applied simultaneously, pressure regulating means formed of linear solenoid valves 71, 72 and pressure regulating valves 61, 62 regulated in pilot pressure by the valves 71, 72 are used in common. Two friction elements and one pressure regulating means are made into one set, and in relation to plural sets thereof, there is provided one switching means formed of an on-off solenoid valve 91 and a switching valve 81 to which the supply/ discharge of switching pressure is performed by the on-off solenoid valve 91.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hydraulic circuit for an automatic transmission,
In particular, the present invention relates to a hydraulic circuit in which adjustment of operating pressure for a plurality of friction elements or supply / discharge control is performed for each friction element.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile is designed to automatically shift a shift stage by selectively engaging a plurality of engaging elements to switch a power transmission path of a transmission gear mechanism. So, in this kind of automatic transmission,
A hydraulic circuit for controlling the supply and discharge of the fastening hydraulic pressure to and from the friction element is provided.

This hydraulic circuit is disclosed, for example, in JP-A-63-18.
As disclosed in Japanese Patent No. 6055, basically,
It is composed of a regulator valve for generating a line pressure of a predetermined pressure and a plurality of shift valves for switching a supply path of the line pressure to each friction element. In that case, in recent years, in order to more appropriately perform the line pressure adjusting operation and the shift valve switching operation by the regulator valve,
A duty solenoid valve or an ON-OFF solenoid valve may be used.

However, according to the conventional hydraulic circuit using such a regulator valve and a shift valve, the same line pressure is supplied to each friction element, so that the requirements of each friction element are met. It is not possible to adjust the individual operating pressures accordingly, and various timing valves are required in order to properly set the supply / discharge timing of the operating pressures during gear shifting.

For this, an operating pressure adjusting means is provided for each friction element, and these adjusting means are used for controlling the supply / discharge timing of the operating pressure at the time of shifting and adjusting the pressure for each friction element. Have been tried to do.

[0006]

By the way, when the operating pressure is adjusted for each friction element as described above, the adjusting means is a pressure regulating valve whose control pressure is adjusted by an electromagnetic valve such as a duty solenoid valve. However, as many sets of the electromagnetic valve and the pressure regulating valve as the number of friction elements are required, so that the hydraulic circuit is complicated and the cost is increased.

Therefore, an object of the present invention is to simplify the structure of a hydraulic circuit in which the adjustment of the operating pressure for a plurality of friction elements or the control of the supply / discharge timing is performed for each friction element.

[0008]

In order to solve the above problems, the hydraulic circuit of the automatic transmission according to the present invention is characterized in that it is configured as follows.

First, the invention according to claim 1 of the present application (hereinafter,
The first invention) is common to two friction elements to which operating pressure is not supplied at the same time in a hydraulic circuit of an automatic transmission in which operating pressures are supplied to a plurality of friction elements and are selectively engaged to switch gears. One switching means that includes a pressure adjusting means, and that sets the two friction elements and one pressure adjusting means as one set, and simultaneously switches the friction elements connected to the pressure adjusting means in each of the plurality of sets. Is provided.

The invention according to claim 2 of the present application (hereinafter,
In the second invention), a pressure regulating valve whose control pressure is adjusted by a linear solenoid valve is used as the pressure regulating means in the first invention, and ON-O is used as the switching means.
It is characterized by using a switching valve in which switching pressure is supplied and discharged by an FF solenoid valve.

[0011]

According to the above construction, the pressure adjusting means is shared by the two friction elements according to both the first invention and the second invention, and the two friction elements and one pressure adjusting means are provided. Since the switching operation is performed by one switching means for a plurality of sets, the total number of the pressure adjusting means and the switching means is smaller than the number of friction elements, and the pressure adjusting means is provided for each friction element. The number of the pressure adjusting means and the like is reduced as compared with the case where it is provided. Since the two friction elements that share one pressure adjusting means are not supplied with the working pressure at the same time, the required gear shift operation performed by selectively supplying the working pressure to each friction element is hindered. Never invite.

According to the second aspect of the invention, the control pressure adjusted by the linear solenoid valve is supplied to the pressure regulating valve constituting the pressure regulating means, so that the operating pressure is supplied to the friction element during shifting. The discharge control can be performed with higher responsiveness than when other valves such as a duty solenoid valve are used.

[0013]

EXAMPLES Examples of the present invention will be described below.

First, the mechanical structure of the automatic transmission according to this embodiment will be described with reference to FIG.
Is a torque converter 20 as a main component,
It has a speed change gear mechanism 30 driven by the output of the converter 20, a plurality of friction engagement elements 41 to 46 such as clutches and brakes for switching the power transmission path of the mechanism 30, and one-way clutches 47 and 48. Each range of D, S, L, R as a running range, 1 to 4 speeds in the D range, 1 to 3 speeds in the S range, 1 in the L range
~ 2nd speed can be obtained.

The torque converter 20 is a pump 2 fixed in a case 21 connected to the engine output shaft 1.
2 and the pump 22 disposed so as to face the pump 22.
A turbine 23 driven by hydraulic fluid by means of a hydraulic fluid, a stator 25 interposed between the pump 22 and the turbine 23 and supported by the transmission case 11 via a one-way clutch 24 to perform a torque increasing action, Case 21
And a turbine 23, and is constituted by a lock-up clutch 26 that directly connects the engine output shaft 1 and the turbine 23 via the case 21. The rotation of the turbine 23 is output to the transmission gear mechanism 30 side via the turbine shaft 27.
Here, the turbine shaft 2 is attached to the engine output shaft 1.
A pump shaft 12 penetrating the inside of the transmission 7 is connected, and the shaft 12 drives an oil pump 13 provided at the rear end of the transmission.

On the other hand, the speed change gear mechanism 30 is composed of a Ravigneaux type planetary gear device, and has a small diameter small sun gear 31 loosely fitted on the turbine shaft 27.
A large-diameter large sun gear 32 that is also loosely fitted on the turbine shaft 27 behind the sun gear 31, a plurality of short pinion gears 33 meshed with the small sun gear 31, and a front half portion meshes with the short pinion gear 33. A long pinion gear 34 whose rear half is meshed with the large sun gear 32, a carrier 35 rotatably supporting the long pinion gear 34 and the short pinion gear 33, and a long pinion gear 34.
And a ring gear 36 meshed with the front half of the.

A forward clutch 41 and a first one-way clutch 47 are provided in series between the turbine shaft 27 and the small sun gear 31, and a coast clutch 42 is provided in parallel with these clutches 41 and 47. A 3-4 clutch 43 is provided between the turbine shaft 27 and the carrier 35, and the turbine shaft 27 and the large sun gear 3 are provided.
A reverse clutch 44 is interposed between the two. A 2-4 brake 45, which is a band brake for fixing the large sun gear 32, is provided between the large sun gear 32 and the reverse clutch 44, and between the carrier 35 and the transmission case 11. , The second one-way clutch 4 that receives the reaction force of the carrier 35
8 and a low reverse brake 4 for fixing the carrier 35
6 and 6 are provided in parallel. The ring gear 36 is connected to the output gear 14, and the rotation is transmitted from the output gear 14 to the left and right wheels (not shown) via a differential device.

Here, the friction engagement elements 41 to 46 such as the above-mentioned clutches and brakes and the one-way clutches 47 and 4 are used.
Table 1 summarizes the relationship between the operating state of No. 8 and the shift speed.

[0019]

[Table 1] Next, the hydraulic circuit 50 that supplies and discharges hydraulic pressure to and from the actuators of the friction engagement elements 41 to 46 and the lockup clutch 26 in the torque converter 20 will be described with reference to FIG.

The hydraulic circuit 50 includes a regulator valve 51 for adjusting the discharge pressure of the oil pump 13 shown in FIG. 1 to a predetermined line pressure and outputting the line pressure to the main line 100, and a constant control valve for reducing the line pressure to a certain level. Line 10 as the source pressure
1 and a reducing valve 52 for outputting to 1. Further, the main line 100 has a manual valve 53.
At the same time, the lockup release line 102 is introduced to the lockup clutch 26 in the torque converter 20, and the line pressure is supplied to the lockup clutch 26 as a release pressure.

The manual valve 53 switches the range of P, R, N, D, S and L by manual operation. In the forward range of D, S and L, the main line 1 is operated.
00 is connected to port a connected to forward line 103, main line 100 is connected to port b connected to reverse line 104 in R range, and line 105 is connected to drain port c in D range. It is designed to communicate.

Of the lines 103 to 105, the forward line 103 is three lines 106 and 10.
7, 108, and its first branch line 106
Is connected to the input port 61a of the first pressure regulating valve 61 via the one-way ball 109 and the line 110, and the second and third branch lines 107, 108 are connected to the second,
Input ports 62a, 64 of the fourth pressure regulating valves 62, 64
a respectively connected to a. The lockup release line 102 (main line 100) through the orifice 11 is connected to the input port 63a of the third pressure regulating valve 63.
The line 112 branched via 1 is connected to the line 112, and the line 112 is connected to the line 105 communicating with the drain port c of the manual valve 53. Further, the line 113 branched from the retreat line 104 is the one-way ball 109 and the line 1
It is connected to the input port 61 a of the first pressure regulating valve 61 via 10.

On the other hand, the control source pressure line 101 has four
Is branched into one line 114, 115, 116, 117, and the first to fourth linear solenoid valves 71, 72, 7
The input ports 71a to 74a of 3, 74 are respectively connected. These linear solenoid valves 71 to 7
4 is the operation of the linear solenoids 71b to 74b,
The control source pressure input to the input ports 71a to 74a is adjusted to a predetermined pilot pressure by a signal from the control unit (see FIG. 3), and the pilot pressure is supplied via lines 118, 119, 120, 121. To supply the pilot ports 61b to 64b of the first to fourth pressure regulating valves 61 to 64, respectively. Therefore,
In each of the pressure regulating valves 61 to 64, the input port 61a
The line pressures input to 64a are adjusted to the above pilot pressures, that is, the hydraulic pressures corresponding to the operation amounts of the linear solenoids 71b to 74b in the linear solenoid valves 71 to 74, respectively. Where the first, third,
In the fourth pressure regulating valves 61, 63, 64, the higher the pilot pressure, the higher the hydraulic pressure that is output, and in the second pressure regulating valve 62, the higher the pilot pressure, the lower the hydraulic pressure that is output.

Then, these hydraulic pressures are used as the operating pressures of the friction elements, and the output ports 61c of the pressure regulating valves 61 to 64 are used.
To 64c, among them, the operating pressure output from the output ports 61c and 62c of the first and second pressure regulating valves 61 and 62 is supplied to the first switching valve 81 via the lines 122 and 123, and the third Output port 6 of pressure regulating valve 63
The operating pressure output from 3c is the second via line 124.
It is supplied to the switching valve 82, and the fourth pressure regulating valve 64
The operating pressure output from the output port 64c of the
It is adapted to be directly supplied to the coast clutch 42 via 5.

The first and second switching valves 81 and 82 are
Each of the switching ports 81a and 82a has a switching port 81a and 82a.
First and second switching lines 126 and 127 branched from 1
Is the first and second ON-OFF solenoid valves 91, 92
Are respectively connected via. These ON-OF
When the F solenoid valves 91 and 92 are ON, the first,
The second switching lines 126, 127 are made to communicate with each other, and at this time, the control source pressure in the line 101 serves as the switching pressure and the switching ports 81a, 8 of the first and second switching valves 81, 82.
2a, the spools of these valves 81 and 82 are located on the right side in the drawing.

The first switching valve 81 has first to fourth input ports 81b, 8 in addition to the switching port 81a.
1c, 81d, 81e and the first and second drain ports 81
f, 81g and the first to fourth output ports 81h, 81i,
81j and 81k, and the first input port 81b has
The retreat line 104 is directly connected, and the output port 6 of the first pressure regulating valve 61 is connected to the second input port 81c.
1c is connected to the line 122, the third input port 81d is directly connected to the forward line 103, and the fourth input port 81e is connected to the output port 62c of the second pressure regulating valve 62. Led line 123
Are connected. Further, the first output port 81h is guided to the reverse clutch 44 via the line 128, and
The output port 81i is guided to the 2-4 brake 45 via the line 129, and the third output port 81j is connected to the line 130.
To the forward clutch 41, and the fourth output port 81k is guided to the 3-4 clutch 43 via the line 131.

When the first ON-OFF solenoid valve 91 is OFF and the spool is located on the left side, the retreat line 1 connected to the first input port 81b.
04 is the reverse clutch 44 from the first output port 81h
Line 122 from the first pressure regulating valve 61 connected to the second input port 81c is connected to the second output port 81i.
From the 2-4 brake 45 to the third input port 81
The forward line 103 connected to d is the third output port 8
1j communicates with the forward clutch 41, and the line 123 from the second pressure regulating valve 62 connected to the fourth input port 81e communicates with the 3-4 clutch 43 from the fourth output port 81k. There is. Further, when the first ON-OFF solenoid valve 91 is ON and the spool is located on the right side, the retreat line 104 connected to the first input port 81b and the third input port 81d.
At the same time that the forward line 103 is cut off, the line 122 from the first pressure regulating valve 61 connected to the second input port 81c communicates with the reverse clutch 44 from the first output port 81h, and the fourth input port 81e. The line 123 from the second pressure regulating valve 62 connected to the third communication port 81j communicates with the forward clutch 41, and
The 2-4 brake 45 and the 3-4 clutch 43 connected to the second output port 81i and the fourth output port 81k are connected to the first and second drain ports 81f and 81g, respectively.

In addition to the switching port 82a, the second switching valve 82 has an input port 82b and first and second switching ports 82a.
Output ports 82c and 82d, a drain port 82e,
It has a cooler output port 82f to which a line 132 leading to an oil cooler is connected together with the port 63d of the third pressure regulating valve 63, and is guided from the output port 63c of the third pressure regulating valve 63 to the input port 82b. Line 12
4 is connected. Further, the first output port 82c is connected to the inside of the torque converter 20 via the line 133,
The second output port 82d is connected to the low reverse brake 46 via a line 134.

Then, when the second ON-OFF solenoid valve 92 is ON and the spool is located on the right side, the line 124 from the third pressure regulating valve 63 connected to the input port 82b receives the torque from the first output port 82c. The low reverse brake 46 communicates with the inside of the converter 20 to supply the engagement pressure of the lockup clutch 26, and communicates with the drain port 82e. In addition, the second ON-OF
When the F solenoid valve 92 is OFF and the spool is located on the left side, the line 124 led from the third pressure regulating valve 63 communicates with the low reverse brake 46 from the second output port 82d and the torque converter 20.
The inside communicates with the cooler output port 82f.

Here, the first to fourth linear solenoid valves 71 to 74 and the first and second ON-OFF solenoid valves 91 and 92 are operated by a signal from the control unit 200 as shown in FIG. It has become. And this control unit 200
Is a signal from a vehicle speed sensor 201 that detects the vehicle speed of the vehicle, a signal from a throttle sensor 202 that detects the throttle opening of the engine, and the position (range) of the shift lever that operates the manual valve 53.
A signal or the like from the shift position sensor 203 for detecting the shift is input to control the shift speed and the lock-up clutch 26 according to the driving state. The relationship between each range and ON / OFF of the first and second ON-OFF solenoid valves 91 and 92 in that case is as shown in Table 2.

[0031]

[Table 2] Next, specific operations of the shift control and the lockup control by the control unit 200 will be described.

First, in the non-travel range P and N ranges, the first and second ON-OFF solenoid valves 9 are used.
Although both 1 and 92 are ON and the spools of the first and second switching valves 81 and 82 are located on the right side, in this case, the manual valve 53 is not connected to any of the input ports of these switching valves 81 and 82. Alternatively, the pressure regulating valve 61 to
No operating pressure is supplied from 64, and therefore each friction element 41 to 46 is released, and the lockup clutch 26 is also released by the release pressure from the lines 100 and 102.

Next, in the D range, the first ON-O
FF solenoid valve 91 is OFF, second ON-OFF
The solenoid valve 92 is turned on, and accordingly, the spool of the first switching valve 81 is on the left side, and the second switching valve 8 is on the left side.
Two spools are located on the right side. Further, in the manual valve 53, the forward line 103 communicates with the main line 100, so that the line 106,
Line pressures via 107 and 108 are input ports 61a and 62 of the first, second and fourth pressure regulating valves 61, 62 and 64, respectively.
up to 64a.

Since the spool of the first switching valve 81 is located on the left side, the advancing line 103 moves the third input port 81d to the third output port 8 of the valve 81.
3i, and further communicates with the forward clutch 41 via the line 130. Therefore, in the D range,
The forward clutch 41 is always engaged.
At this time, the first output port 81h to which the reverse clutch 44 is connected communicates with the first input port 81b, but the reverse line 104 connected to the first input port 81b is drained at the manual valve 53. Therefore, the reverse clutch 44 is not engaged in the D range.

Then, in the D range, when the first speed is set as the first speed, the signal from the control unit 200 stops the supply of pilot pressure from the first linear solenoid valve 71 to the first pressure regulating valve 61. Then, the pilot pressure is supplied from the second linear solenoid valve 72 to the second pressure regulating valve 62. As a result, the output ports 61c of the first and second pressure regulating valves 61 and 62,
No operating pressure is output from 62c, so that only the forward clutch 41 is engaged, and the shift speed becomes the first speed.

When the shift speed is set to the second speed, the first linear solenoid valve 71 operates from the above-described first speed state and the pilot pressure is supplied to the first pressure regulating valve 61.
At this time, the operating pressure is supplied from the output port 61c of the first pressure regulating valve 61 to the second input port 81c of the first switching valve 81 via the line 122, and this operating pressure is supplied to the first switching valve 81. Line 1 from the second output port 81i
It is supplied to the 2-4 brake 45 via 29. As a result, the 2-4 brake 45 is engaged in addition to the forward clutch 41, and the shift speed becomes the second speed.

Further, when the shift speed is set to the third speed, the first and second linear solenoid valves 71, 7 are moved from the second speed state.
2 operates, and the supply of pilot pressure to the first and second pressure regulating valves 61 and 62 is stopped. Therefore, the output of the working pressure from the first pressure regulating valve 61 is stopped, the 2-4 brake 45 is released, and at the same time, the second pressure regulating valve 62 is released.
The operating pressure is supplied to the fourth input port 81e of the first switching valve 81 from the output port 62c of the above through the line 123. This operating pressure is supplied from the fourth output port 81k of the first switching valve 81 to the 3-4 clutch 43 via the line 131. Therefore, in addition to the forward clutch 41, the 3-4 clutch 43 is provided.
Is engaged, and the shift speed becomes the third speed.

Further, when the shift speed is set to the fourth speed, the first linear solenoid valve 71 operates from the state of the third speed and the pilot pressure is supplied to the first pressure regulating valve 61 again. Therefore, the 2-4 brake 45 is re-engaged and the forward clutch 4 is engaged as in the case of the above-described second speed.
Since the 1st and 3-4 clutches 45 are in the engaged state, the shift stage is the 4th speed.

Here, in each of the above shift speeds, the first,
The operating pressures regulated by the first and second pressure regulating valves 61, 62 according to the actuation amounts of the second linear solenoid valves 71, 72 are supplied to the 2-4 brake 45 and the 3-4 clutch 43, respectively. The torque transmission capacities of these friction elements 43, 45 are adjusted to their respective optimum values, and the supply / discharge timing of the operating pressure is particularly controlled appropriately at the time of shifting the gear, so that the gear shifting operation causes a shock or the like. It will be carried out satisfactorily.

Further, at these shift speeds, the third linear solenoid valve 73 operates as necessary to supply pilot pressure to the third pressure regulating valve 63, so that the output of the third pressure regulating valve 63 is increased. Line 63 from port 63c
The operating pressure is supplied to the input port 82b of the second switching valve 82 via. Then, this operating pressure is introduced into the torque converter 20 through the line 133, and acts so as to engage the lockup clutch 26. In that case, the pilot pressure or the working pressure introduced into the torque converter 20 is adjusted according to the working amount of the third linear solenoid valve 73, so that the lockup clutch 26 is completely engaged or a predetermined slippage occurs. Controlled by the state.

Further, in the S range and the L range, the first and second ON-OFF solenoid valves 9 are operated at the first speed.
Both 1 and 92 are turned off, and along with this, the first and second
The spools of the switching valves 81 and 82 are both located on the left side. Therefore, although the forward clutch 41 is engaged via the first switching valve 81 as in the case of the D range, the output port 6 of the third pressure regulating valve 63 is used.
The operating pressure supplied from 3c to the input port 82b of the second switching valve 82 via the line 124 is introduced from the second output port 82d to the low reverse brake 46 via the line 134. Therefore, in the S and L ranges, the low reverse brake 46 is engaged, and the first speed in which the engine brake operates during deceleration is obtained.

In addition to the first speed, the second ON-O
By turning on the FF solenoid valve 92, second and third speeds can be obtained in exactly the same manner as in the case of the D range.

In the first speed in the S and L ranges, the third pressure regulating valve 63 and the second switching valve 82 are used for supplying the working pressure to the low reverse brake 46, so that the torque converter 20 is provided. The engagement operation of the lockup clutch 26 due to the supply of the operating pressure to the lockup clutch 26 is not performed.

Further, in the above forward range, the fourth linear solenoid valve 74 operates at the required shift speed to supply the pilot pressure to the fourth pressure regulating valve 64.
Therefore, the operating pressure is supplied from the output port 64c of the fourth pressure regulating valve 64 to the coast clutch 42 via the line 125, the coast clutch 42 is engaged, and the engine brake operates during deceleration. In that case, the gear stages for engaging the coast clutch 42 are set to the second and third speeds of the D range, the second and third speeds of the S range, the second speed of the L range, etc., as shown in Table 1 above. .

On the other hand, in reverse speed, the first and second ON
-OFF The solenoid valves 91 and 92 are both turned off, the spools of the first and second switching valves 81 and 82 are both located on the left side, and the manual valve 53 has the port b to which the retreat line 104 is connected. Leads to the main line 100. Therefore, the line pressure is supplied to the first input port 81b of the first switching valve 81 via the retreat line 104, and the valve 81 is further supplied.
Is supplied to the reverse clutch 44 from the first output port 81h of the reverse clutch 44 through the line 128.
Is concluded. In this case, the input port 61a of the first pressure regulating valve 61 from the retreat line 104 through the branch line 113, the one-way ball 109 and the line 110.
Although the line pressure is supplied to, the output of the operating pressure from the output port 61c of the first pressure regulating valve 61 is stopped by the operation of the first linear solenoid valve 71.
The 4 brake 45 is never engaged.

In this R range, since the drain port c of the manual valve 53 to which the line 105 is connected is closed, the main line 100 to the line 10 are closed.
The line pressure is supplied to the input port 63a of the third pressure regulating valve 63 via the line 112 having the 2 and the orifice 111. Then, the pilot pressure is supplied to the third pressure regulating valve 63 by the operation of the third linear solenoid valve 73, and the working pressure is output from the output port 63c of the third pressure regulating valve 63. This operating pressure is supplied to the input port 82b of the second switching valve 82 via the line 124, and is further supplied to the low reverse brake 46 via the line 134 because the spool of the valve 82 is located on the left side. , The low reverse brake 46 is engaged. As a result, the reverse clutch 44 and the low reverse brake 46 are engaged, and a reverse speed is obtained.

Further, the hydraulic circuit 50 operates in the D, S, L and R ranges from the non-running range such as the N range or the P range.
In order to suppress the so-called ND shock or NR shock that accompanies switching to the running range such as the range, the following operation is performed.

That is, in the non-driving range, the first O
Since the N-OFF solenoid valve 91 is ON and the spool of the first switching valve 81 is located on the right side, the output ports 61c, 6 of the first and second pressure regulating valves 61, 62 are
2c is the second and fourth input ports 8 of the first switching valve 81.
1c, 81e and first and third output ports 81h, 81j
The reverse clutch 44 and the forward clutch 41 are respectively communicated with each other via the, and the neutral state is maintained by stopping the output of the operating pressure from the first and second pressure regulating valves 61 and 62 in this state. . Then, when the manual valve 53 is operated when switching from this state to the traveling range, the line pressure is changed from the backward line 104 to the line 113, the one-way ball 109 and the line 1.
10 is supplied to the input port 61a of the first pressure regulating valve 61, or from the forward line 103 to the line 107.
If the first linear solenoid valve 71 or the second linear solenoid valve 72 is operated in this state while being supplied to the input port 62a of the second pressure regulating valve 62 via the Regulator valve 6
In that case, the operating pressure is output from the second clutch, the reverse clutch 44 or the forward clutch 41 is engaged, and the shift speed is switched to the reverse speed or the first speed. In that case, the first linear solenoid valve 71 or the second linear solenoid valve 71
When the linear solenoid valve 72 is actuated, if the actuation amount and actuation timing are appropriately controlled, the rise of the actuation pressure supplied to the reverse clutch 44 or the forward clutch 41 will be in the most favorable state. The shock generated when the clutches 44 and 41 are engaged is reduced.

Then, after that, the first ON-OFF solenoid valve 91 is turned off, and the first switching valve 8 is turned on.
If you move the spool of 1 to the left side, as described above,
Reverse clutch 44 or forward clutch 41
Then, the line pressure is directly supplied from the reverse line 104 or the forward line 103, and the normal reverse speed state or the first speed state is entered.

As described above, according to the hydraulic circuit 50, control of the shift speed, control of the lockup clutch 26,
Control of the coast clutch 42 for engine braking, reduction control of shift shock at the time of switching from the non-running range to the running range, and the like are performed. Particularly, adjustment or supply of operating pressure to a plurality of friction elements is performed. Even though the discharge timing control is performed for each friction element, each control described above is realized with a small number of valves by sharing the valve for each friction element. That is, the first
The pressure regulating valve 61 and the first linear solenoid valve 71 for controlling the pressure regulating valve 61 are shared by the reverse clutch 44 and the 2-4 brake 45 at the 2nd and 4th speeds when the N-R switching is not performed at the same time. The pressure valve 62 and the second linear solenoid valve 72 for controlling the pressure valve 62 are shared by the forward clutch 41 and the 3-4 clutch 43 in the 3rd and 4th speeds when the N-D switching is not performed at the same time. Further, the third pressure regulating valve 63 and the third linear solenoid valve 73 for controlling the third pressure regulating valve 63 and the low reverse brake 4 do not operate at the same time.
It is shared with 6 and 6. Regarding the first and second pressure regulating valves 61 and 62, the operation of the reverse clutch 44 at the time of the N-R switching and the 2nd speed at the 2nd and 4th speeds are performed.
-4 The operation of the brake 45 is switched, the operation of the forward clutch 41 at the time of ND switching, and the operation at the 3rd and 4th speeds are performed.
-4 The switching of the operation of the clutch 43 is performed by sharing the first switching valve 81 and the first ON-OFF solenoid valve 91 for controlling the same, and in this way, a small number of valves are required. All the actions that are performed are executed.

[0051]

As described above, according to the present invention, the pressure adjusting means is shared for the two friction elements that do not operate at the same time, and the two friction elements and the one pressure adjusting means are combined. Since one switching means is provided for a plurality of sets, the total number of the pressure adjusting means and the switching means is smaller than the case where the pressure adjusting means is provided for each friction element. As a result, a hydraulic circuit having a simple structure and a low cost can be realized as a hydraulic circuit for adjusting the operating pressure and controlling the supply / discharge timing for each friction element.

According to the second aspect of the invention, since the linear solenoid valve is used as the control means of the pressure adjusting means, the supply / discharge control of the working pressure to the friction element at the time of shifting can be performed with good responsiveness. Like

[Brief description of drawings]

FIG. 1 is a skeleton diagram of an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of the embodiment.

FIG. 3 is a control system diagram of the embodiment.

[Explanation of symbols]

41-46 Friction element 50 hydraulic circuit 61-64 Pressure regulating valve 71-74 Linear solenoid valve 81,82 switching valve 91, 92 ON-OFF solenoid valve

Claims (2)

[Claims] 1. A hydraulic circuit of an automatic transmission for switching a gear stage by supplying operating pressure to a plurality of friction elements and selectively engaging them, which is common to two friction elements to which operating pressure is not supplied at the same time. One switching means that includes a pressure adjusting means, and that sets the two friction elements and one pressure adjusting means as one set, and simultaneously switches the friction elements connected to the pressure adjusting means in each of the plurality of sets. A hydraulic circuit for an automatic transmission characterized by being provided with. 2. The pressure adjusting means is a pressure adjusting valve whose control pressure is adjusted by a linear solenoid valve, and the switching means is O.
The hydraulic circuit for an automatic transmission according to claim 1, wherein the hydraulic circuit is a switching valve in which switching pressure is supplied and discharged by an N-OFF solenoid valve.