JPH0783323A - Oil pressure controller of automatic transmission - Google Patents

Abstract

PURPOSE:To appropriately suppress shock at the time of clamping frictional element. CONSTITUTION:A reducing valve 77 is set on a line 125 in which line pressure is introduced when it is set at L range, and then the line 125 is connected to one end of a ball valve 78 continuing to a rolley berth brake 46 via a rolley berth brake line 127, etc. A line 129 in which the line pressure in produced when it is set in a R range is connected to the other end of the ball valve 78. A line 163 is branched from the output line 141 of a modulator valve 89 for line pressure control for variably controlling the output pressure, for example by a duty solenoid valve 90, and the line 163 is connected to the control port 77a of the reducing valve 77.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to a hydraulic control device for an automatic transmission configured to engage a predetermined friction element in an engine braking range such as an L range.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile is a combination of a torque converter and a speed change mechanism, and a power transmission path of the speed change mechanism is switched by selective operation of a plurality of friction elements such as clutches and brakes. The automatic transmission of this type is provided with a hydraulic control circuit for controlling the supply and discharge of hydraulic pressure to and from the actuators of the friction elements. This hydraulic control circuit includes, for example, a regulator valve that adjusts the discharge pressure of the oil pump to a predetermined line pressure, a manual valve that switches the range by manual operation,
A plurality of shift valves and the like are provided that are activated according to operating conditions and switch the oil passages leading to the actuators to selectively activate a plurality of friction elements.
Then, in recent years, a duty solenoid valve for changing the adjustment value of the line pressure by the regulator valve according to an operating state such as the throttle opening of the engine, or an ON-type valve for activating a shift valve at the time of gear shifting.
There may be a case where an OFF solenoid valve or the like is provided and these are electrically controlled so that the shift control can be accurately performed.

On the other hand, in this type of automatic transmission, in order to achieve both coasting performance and engine braking performance, for example, a low-reverse brake is provided in parallel with a one-way clutch that idles during coasting.
In some normal driving ranges such as ranges, the low reverse brake is set in a released state, and the low reverse brake is engaged when the range is switched to an engine braking range such as the L range. According to this, for example, when the accelerator pedal is released while the vehicle is running in the D range, good coasting performance can be obtained because the one-way clutch parallel to the low reverse brake idles, and the range can be adjusted by operating the shift lever. Since the low reverse brake is engaged when switching to the L range, strong engine braking performance is also secured.

By the way, when the range is shifted from the D range to the L range for the purpose of operating the engine brake, the line pressure is directly supplied to the low reverse brake. However, when the brake is applied, a great shock occurs, which deteriorates the riding comfort of the vehicle.

To solve this problem, for example, Japanese Patent Laid-Open No. 4-5
As disclosed in Japanese Patent Publication No. 9, a decompression valve is installed in a fastening oil passage leading to the low reverse brake, and
O is fed to the control source pressure oil passage led to the control port of the pressure reducing valve.
When an N-OFF solenoid valve is connected, for example, when manually shifting from the D range to the L range, the ON-OFF solenoid valve is turned on until a predetermined time elapses.
As the control pressure acting on the pressure reducing valve is discharged through the control port, the output pressure of the pressure reducing valve is reduced, and the ON-OF is reduced after a predetermined time has elapsed.
A configuration is shown in which the output pressure of the pressure reducing valve is increased by turning off the F solenoid valve and applying a control pressure to the pressure reducing valve. According to this
Since the engagement pressure supplied to the low reverse brake rises via an intermediate pressure state called a shelf pressure, the shock at the time of engagement is reduced.

[0006]

However, even in the prior art described in the above publication, there is still room for improvement as described below.

That is, it is assumed that, for example, the range is switched from the D range to the L range in order to operate the engine brake when the automobile is running. In this case, when the shelf pressure level supplied to the low reverse brake is set to a relatively low level in order to give priority to the suppression of shocks, the low reverse due to the inertia of the vehicle during gear shifting from the high speed running state. The brakes will slip unnecessarily, which not only causes a problem in durability, but also causes the driver to feel an unintended idling feeling. In order to deal with this, if the above shelf pressure level is set to a high level, the low reverse brake will be quickly engaged when shifting from a low speed running state, and a large shock will occur. It becomes.

The present invention addresses the above-mentioned problems that occur when the range is switched to the engine brake range in an automatic transmission provided with an engine brake friction element that is engaged in the engine brake range. An object of the present invention is to appropriately suppress a shock at the time of engaging the friction element without complicating the structure of the hydraulic control circuit in this type of automatic transmission.

[0009]

That is, a hydraulic control device for an automatic transmission according to the invention of claim 1 of the present application (hereinafter referred to as the first invention) is a friction element for an engine brake that is engaged in an engine brake range. And an oil pressure control circuit having a pressure reducing valve for reducing the engagement pressure supplied to the friction element for engine braking, and a regulator valve for adjusting the line pressure. The electromagnetic hydraulic control means for controlling the line pressure by electrically changing the control pressure to be applied, and the control pressure for supplying the hydraulic pressure controlled by the operation of this control means to the control port for adjusting the output pressure in the pressure reducing valve. A supply means is provided.

In a hydraulic control device for an automatic transmission according to a second aspect of the present invention (hereinafter referred to as the second aspect of the invention), the control pressure supply means of the first aspect of the invention is used for adjusting the output pressure of the pressure reducing valve. It is characterized in that the control pressure supplied to the regulator valve is distributed and supplied to the control port.

The invention of claim 3 of the present application (hereinafter, referred to as the third
The hydraulic control device for an automatic transmission according to the invention is a low reverse brake in which the engine brake friction element in the first and second inventions is engaged in the engine brake range and the reverse range on the low speed stage side. The hydraulic control circuit includes a first oil passage to which the working oil pressure is supplied when the range is set to the engine braking range, and a second oil passage to which the working oil pressure is supplied when the range is set to the reverse range. In the case where a switching valve for selectively communicating the first and second oil passages with the oil passage leading to the low reverse brake by the movement of the shuttle ball is provided, the first valve upstream of the switching valve is provided. It is characterized in that a pressure reducing valve is arranged on the oil passage.

On the other hand, the invention of claim 4 of the present application (hereinafter, referred to as the fourth
The hydraulic control device for an automatic transmission according to the invention is a low reverse brake in which the engine brake friction element in the first and second inventions is engaged in the engine brake range and the reverse range on the low speed stage side. The hydraulic control circuit includes a first oil passage to which the working oil pressure is supplied when the range is set to the engine braking range, and a second oil passage to which the working oil pressure is supplied when the range is set to the reverse range. When a switching valve that selectively connects the first and second oil passages to the oil passage that communicates with the low reverse brake by the movement of the shuttle ball is provided, the low reverse brake downstream of the switching valve. A pressure reducing valve is arranged on the oil passage leading to the.

[0013]

According to the above construction, the following operation can be obtained.

That is, in any of the first to fourth inventions, the hydraulic pressure controlled by the electromagnetic hydraulic control means is supplied to the control port of the pressure reducing valve for the friction element for engine brake such as low reverse brake. Therefore, when the friction element is engaged, if the control pressure or line pressure of the regulator valve adjusted by the electromagnetic hydraulic pressure control means is changed according to the vehicle speed, the output pressure generated by the pressure reducing valve also becomes the vehicle speed. Therefore, it is possible to effectively suppress the shock that occurs when the friction element is fastened.
Moreover, since the electromagnetic hydraulic pressure control means is used for adjusting the line pressure, the structure of the hydraulic pressure control circuit in the automatic transmission of this type is simplified.

In particular, according to the second aspect of the invention, the control pressure supplied to the regulator valve is supplied as the control pressure for adjusting the output pressure of the pressure reducing valve to the friction element for engine braking. The output pressure of the pressure reducing valve can be precisely controlled, and the shock can be suppressed more effectively.

According to the third aspect of the invention, the friction element for engine braking is a low reverse brake which is fastened between the engine braking range and the reverse range on the low speed stage side, and the hydraulic control circuit includes a range. A first oil passage to which the working oil pressure is supplied when the engine brake range is set, and a second oil passage to which the working oil pressure is supplied when the engine brake range is set to the reverse range, and the first and second oil passages. An automatic transmission provided with a switching valve that selectively communicates with an oil passage communicating with the low reverse brake by movement of a shuttle ball. A pressure reducing valve is arranged on the first oil passage upstream of the switching valve. Therefore, even if the spool of the pressure reducing valve is stuck at the time of shifting to the reverse range, the reverse stage is reliably achieved and It means that vacuum pressure is led to the valve, there is a practical benefit in that the durability of the shuttle ball or separate plate constituting the said changeover switching valve is improved.

On the other hand, according to the fourth aspect of the invention, since the pressure reducing valve is arranged on the downstream side of the switching valve, the fastening pressure supplied to the low reverse brake is controlled by the pressure reducing valve even during the shift operation to the reverse range. Not only can it be controlled by using it, but there is the actual benefit that an accumulator for forming the shelf pressure is unnecessary.

[0018]

EXAMPLES Examples of the present invention will be described below.

First, the mechanical structure of the automatic transmission 10 according to the embodiment will be described with reference to FIG.
Is a torque converter 20 as a main component,
Transmission mechanism 30 driven by the output of the converter 20
And a plurality of friction elements 41 to 46 such as clutches and brakes for switching the power transmission path of the mechanism 30 and one-way clutches 51 and 52, by which the D, S, L and R ranges as a travel range are provided. And 1 to 4 speeds in the D range, 1 to 3 speeds in the S range, and 1 in the L range
You can get 2nd speed.

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 oil by means of a hydraulic fluid, and 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 2 above
1 and the turbine 23, and is constituted by a lockup 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 mechanism 30 side via the turbine shaft 27. Here, a pump shaft 12 penetrating the inside of the turbine shaft 27 is connected to the engine output shaft 1, and the oil pump 13 provided at the rear end portion of the transmission by the shaft 12
Are being driven.

On the other hand, the speed change mechanism 30 is constituted by a Ravigneaux type planetary gear unit, and the turbine shaft 27
A small-sized small sun gear 31 loosely fitted on the upper side, and a turbine shaft 27 on the rear side of the sun gear 31
A large sun gear 32 having a large diameter loosely fitted above, a plurality of short pinion gears 33 meshed with the small sun gear 31, and a front half of 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 ring gear 36 meshed with the long pinion gear 34. It is composed of.

A forward clutch 41 and a first one-way clutch 51 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 51. 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. Further, between the large sun gear 32 and the reverse clutch 44, a 2-4 brake 45, which is a band brake for fixing the large sun gear 32, is provided, and
A second one-way clutch 52 that receives the reaction force of the carrier 35 and a low reverse brake 46 that fixes the carrier 35 are provided in parallel between the carrier 35 and the transmission case 11. 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 elements 41 to 46 such as the above-mentioned clutches and brakes and the one-way clutches 51 and 52.
Table 1 below summarizes the relationship between the operating state and the gear position.

[0024]

[Table 1] Next, a hydraulic control circuit that supplies and discharges hydraulic pressure to and from the actuators of the friction elements 41 to 46 will be described.
The automatic transmission 10 is provided with a hydraulic control circuit 60 as shown in FIG. Here, among the above actuators, the hydraulic actuator 4 of the 2-4 brake 45
5a is composed of a servo piston having an apply port 45b and a release port 45c.
When the hydraulic pressure is supplied only to 5b, the 2-4 brake 45 is engaged, and when the hydraulic pressure is not supplied to both ports 45b and 45c and when the hydraulic pressure is supplied to both ports 45b and 45c, 2 -4 The brake 45 is released. In addition, other friction elements 41 to 4
The actuators 4, 46 are composed of normal hydraulic pistons, and when the hydraulic pressure is supplied, the friction elements are engaged.

The hydraulic control circuit 60 has, as main components, a regulator valve 61 for adjusting the pressure of the hydraulic oil discharged from the oil pump 13 shown in FIG. 1 to the main line 110 to a predetermined line pressure, and a manual operation. A manual valve 62 for selecting a range by means of each of the friction elements (actuators) 41 to 4 which operates in accordance with a gear position.
First, second, and third shift valves 63, 64, and 65 for supplying and discharging hydraulic pressure to and from the engine 6 are provided.

The manual valve 62 includes D, S, L
Each forward range, R range, N range, and P range can be set. In the forward range, the main line 110 is connected to the forward line 111, and in the R range, it is connected to the backward line 112. It has become.

The first, second, and third shift valves 63, 64, 65 have control ports 63 at one end.
a, 64a, 65a are provided. And the first,
Control ports 63a, 6 of the second shift valves 63, 64
4a is connected to the first and second control source pressure lines 113 and 114 respectively branched from the forward line 111, and the control port 65a of the third shift valve 65 is provided with the third control source pressure line 115. In addition to being connected, these control source pressure lines 113, 114, 115 are provided with first, second, and third ON-OFF solenoid valves 66, 67, 68 for shifting, respectively. Of these, the first and second ON-OFF solenoid valves 66,
67 is an ordinary two-way valve, each of which is ON
The control pressures of the corresponding control ports 63a and 64a are discharged to position the spools of the first and second shift valves 63 and 64 on the left side in the drawing, and when the spools are off, the control ports 63a and 64a are controlled. A control pressure is introduced from the first and second control source pressure lines 113 and 114 to position the spool on the right side against the biasing force of the spring.

On the other hand, the third ON-OFF solenoid valve 68 is composed of a three-way valve, and when it is ON, the third control source pressure line 115 on the upstream side is shut off, and
In that state, the control port 65 of the third shift valve 65
The control pressure of a is discharged, and the spool of the valve 65 is positioned on the right side in the drawing. Also, OFF
At this time, the control pressure is introduced from the third control source pressure line 115 to the control port 65a, and in this case as well, the spool is positioned on the left side against the biasing force of the spring.

Here, these ON-OFF solenoid valves 66 to 68 are turned on based on a map preset according to the vehicle speed of the automobile and the throttle opening of the engine in response to a signal from a controller described later. OF
These friction elements 41 to 46 are shown in Table 1 above by F control, and accordingly, the spool positions of the shift valves 63 to 65 are switched and the oil passages leading to the friction elements 41 to 46 are switched. The gears are fastened in combination so that the shift speed can be switched according to the operating condition. In that case, each shift stage in the forward range of D, S, L and each ON-OFF solenoid valve 66 to
The relationship between the 68 ON / OFF combination pattern is set as shown in Table 2 below.

[0030]

[Table 2] On the other hand, the spool of the manual valve 62 is set to D, S,
Main line 110 when set to each forward range of L
A line 116 is branched from a forward line 111 communicating with the forward clutch 41. The line 116 serves as a forward clutch line, and the forward clutch 41 is connected via a one-way orifice 69 that performs a throttle action in the hydraulic oil supply direction.
Have been led to. Therefore, the forward clutch 41 is always engaged in the D, S, and L ranges. An ND accumulator 70 is connected to the forward clutch line 116 downstream of the one-way orifice 69.

The forward line 111 is guided to the first shift valve 63, the first ON-OFF solenoid valve 66 is turned ON, and the spool of the shift valve 63 is positioned on the left side. Servo piston 45a communicating with each other and through the orifice 71
To the Apply port 45b. Therefore, D, S,
The first ON-OFF solenoid valve 66 is O in the L range.
At N, that is, at the 2nd, 3rd and 4th speeds in the D range, the 2nd and 3rd speeds in the S range, and the 2nd speed in the L range, hydraulic pressure (servo apply pressure) is introduced to the apply port 45b, and the release port 45c. The 2-4 brake 45 is engaged when the hydraulic pressure (servo release pressure) is not introduced. In addition, line 1 is provided at the above-mentioned Apply port 45b.
1 via 18 and timing control valve 72
-2 accumulator 73 is connected.

The forward line 111 is also guided to the third shift valve 65, the third ON-OFF solenoid valve 68 is OFF, and when the spool of the shift valve 65 is located on the left side, the coast clutch line 119.
Communicate with. The coast clutch line 119 reaches the coast clutch 42 via a coast reducing valve 74 and a one-way orifice 75 that performs a throttle action in the hydraulic oil supply direction. Therefore, the third ON-OFF solenoid valve 68 is OFF in the D, S, L ranges.
At this time, that is, the coast clutch 42 is engaged in the third speed of the D and S ranges, the second speed of the S and L ranges, and the first speed of the L range.

Further, the forward line 111 is also led to the second shift valve 64. And the line 111
The second ON-OFF solenoid valve 67 is OFF
Thus, when the spool of the second shift valve 64 is located on the right side, it communicates with the 3-4 clutch line 120. The line 120 further reaches the 3-4 clutch 43 via the 3-4 control valve 76. Therefore,
When the second ON-OFF solenoid valve 67 is OFF in the D, S, and L ranges, that is, the 3-4 clutch 43 is engaged in the 3rd and 4th speeds of the D range and the 3rd speed of the S range.

Here, the 3-4 clutch line 120 is used.
The line 121 branched from the line is guided to the third shift valve 65, and the third ON-OFF solenoid valve 68 is opened.
At F, when the spool of the shift valve 65 is located on the left side, it communicates with the servo release line 122 that communicates with the release port 45c of the servo piston 45a. Therefore, when the second and third ON-OFF solenoid valves 67, 68 are both OFF in the D, S, L ranges, that is, in the third speed of the D range and the third speed of the S range, the servo is applied to the release port 45c of the servo piston 45a. Release pressure is introduced and the 2-4 brake 45 is released.

A line 123 is branched from the forward line 111, and this line 123 also has the second line.
It is guided to the shift valve 64. This line 123
Is the second ON-OFF solenoid valve 67 is ON,
When the spool of the second shift valve 64 is located on the left side, it communicates with the line 124 that communicates with the first shift valve 63. On the other hand, the first shift valve 63 has a first ON-OF
When the F solenoid valve 66 is OFF and the spool of the valve 63 is located on the right side, a line 125 communicating with the line 124 is connected, and the line 125 is connected via a low reducing valve 77, a ball valve 78 and a line 126. 3rd ON-OFF solenoid valve 6
Guided to 8. And this line 126 is the third
When the ON-OFF solenoid valve 68 is OFF and the spool of the third shift valve 65 is located on the left side, it communicates with the low reverse brake line 127 leading to the low reverse brake 46. Therefore, in the D, S, and L ranges, the first, second, and third ON-OFF solenoid valves 6
When 6 to 68 are OFF, ON, and OFF, respectively, that is, the low reverse brake 46 is engaged at the first speed in the L range.

Here, when the spool of the second shift valve 64 is located on the left side, the line 124 communicating with the forward line 111 via the line 123 communicates with the pressure reducing restriction port 74a of the coast control valve 74. Line 128 is connected. The line pressure of the main line 110 is constantly supplied to the back pressure port 74b formed on one end side of the coast control valve 74. Therefore, the second O in the S and L ranges
When the N-OFF solenoid valve 67 is ON, specifically, the first and second speeds in the S range and the first and second speeds in the L range, the main line 110 is always guided to the back pressure port 74b of the coast control valve 74. In addition to the above line pressure, the line pressure of the forward line 111 is also supplied to the pressure reduction limiting port 74a via the line 123, the line 124, and the line 128, and the pressure reduction of the coast clutch pressure is suppressed accordingly. As a result, the transmission torque of the coast clutch 42 increases. On the other hand, when the second ON-OFF solenoid valve 67 is OFF in the D and S ranges, specifically, the third speed in the D range and the third speed in the S range, the spool of the second shift valve 64 should be located on the left side. From the decompression restriction port 74 in the coast control valve 74
a communicates with the drain port of the shift valve 64 via the lines 128 and 124. As a result, the coast control valve 74 is released from the depressurized state, and the coast clutch pressure is reduced by that amount as compared to the above case, and the coast clutch 4 is accordingly reduced.
The transmission torque of 2 will also decrease.

Further, a line 129 is branched from the retreat line 112 communicating with the main line 110 in the R range, and this line 129 is also as shown in FIG.
It is guided to the other end of the ball valve 78 via a one-way orifice 79 or the like that performs a throttle action in the hydraulic oil supply direction.

A shuttle ball 78a is built in the ball valve 78, and when the line pressure from the retreat line 112 is supplied through the line 129,
Since the shuttle ball 78a is located on one end side as shown in the figure, the shuttle ball 78a is moved to the first position via the low reducing valve 77.
The line 125 communicating with the shift valve 63 is blocked, and the line 129 is communicated with the line 126 communicating with the third shift valve 65.

The reverse line 112 serves as a reverse clutch line 130, and a reverse clutch 4 is provided via a one-way valve 80 that opens when hydraulic oil is supplied.
It has reached 4. Therefore, in the R range, the third ON
While the low-off brake 46 is engaged when the -OFF solenoid valve 68 is off, the reverse clutch 44 is always engaged. A line 131 branched from the line 128 between the one-way orifice 79 and the ball valve 78.
An N-R accumulator 81 is connected to.

Further, in the forward range such as the D range, when the line pressure from the forward line 111 is supplied to the line 125 leading to the ball valve 78, the shuttle ball 78a in the ball valve 78 is moved to the position shown in FIG.
From the state of 1 to the other end side, the line 1
25 is connected to the line 126, and the line 129 leading to the retreat line 112 is cut off.

Further, the hydraulic control circuit 60 includes the hydraulic circuit shown in FIG.
A fourth shift valve 82 for controlling the lockup clutch 26 in the torque converter 20 and a lockup control valve 83 shown in FIG.

The fourth shift valve 82 and the lockup control valve 83 include a regulator valve 6
The converter line 132 led from 1 is connected, and the control source pressure line 133 branched from the main line 110 is connected to the control port 82a provided at one end of the fourth shift valve 82. Also, the fourth
In the control port 82a of the shift valve 82,
Fourth ON-OFF solenoid valve 8 for lockup
4 is connected and the spool of the fourth shift valve 82 is located on the left side when the ON-OFF solenoid valve 84 is OFF, so that the converter line 132 causes the lock-up release chamber 26a in the torque converter 20. The lockup clutch 26 is released to enter the converter state. Here, a converter relief valve 85 is connected to the line 135 connected to the fourth shift valve 82 so as to always communicate with the converter line 132.

On the other hand, when the fourth ON-OFF solenoid valve 84 is turned on and the control pressure is discharged from the control port 82a of the fourth shift valve 82, the spool of the valve 82 moves to the right side in the drawing. When moved, the converter line 132 communicates with the engagement line 136 that communicates with the lockup engagement chamber 26b in the torque converter 20, whereby the lockup clutch 26 is engaged. Then, at this time, the release line 134 is the fourth
The lockup control valve 83 is communicated with the lockup release valve 26 via the shift valve 82 and the intermediate line 137, and the operating pressure adjusted by the control valve 83 is supplied to the lockup release chamber 26a as a lockup release pressure.

That is, the control source pressure line 138 led from the main line 110 through the reducing valve 86 is connected to the control port 83a at one end of the lockup control valve 83, and the other end side thereof is connected. A pressure regulation prevention line 139 leading to the forward line 111 is connected to the pressure regulation prevention port 83b. A first duty solenoid valve 88 is installed on the downstream side of the orifice 87 provided in the control source pressure line 138, and the lockup control is performed according to the duty value given to the first duty solenoid valve 88. By adjusting the control pressure supplied to the control port 83a of the valve 83, the pressure regulation blocking port 83 on the other end side
The converter in-line 13 is provided on condition that the line pressure is not supplied to b via the pressure regulation blocking line 139.
2 and the fastening line 136 through the lock-up fastening chamber 2
The differential pressure between the engagement pressure supplied to 6a and the release pressure supplied to the lockup release chamber 26b via the intermediate line 137 and the release line 134 is adjusted, and the lockup clutch 26 is controlled to a predetermined slip state. To be done.

On the other hand, the lockup control valve 8
The pressure regulation prevention line 139 is attached to the pressure regulation prevention port 83b of No. 3 described above.
When the line pressure is supplied via the, the spool of the control valve 83 is fixed in a state of being located on the left side. Therefore, the lock-up release chamber 26a
The operating pressure of the release line 134, the fourth shift valve 82
Also, the pressure is drained from the drain port 83c of the lock-up control valve 83 via the intermediate line 137, and the lock-up clutch 26 is in a completely engaged lock-up state. In that case, the drain port 83c is provided with an orifice whose diameter is appropriately set, so that the hydraulic oil supplied to the lock-up fastening chamber 26b via the fastening line 136 is in a communicating state. Even if it flows into the lockup release chamber 26a, it is not excessively discharged.

In addition, since the lockup state and the slip state are switched by controlling the line pressure supply state to the pressure regulation blocking port 83b of the lockup control valve 83, the control valve 83 is regulated. By setting the pressure range small, it becomes possible to precisely control the engagement force of the lockup clutch 26 in the slip mode.

The operation characteristic of the first duty solenoid valve 88 is set so that the duty control pressure decreases as the duty value D increases. That is, when the duty value D is 1, the drain port is always open, and the pressure level of the control source pressure line 138 on the downstream side of the orifice 87 is the maximum pressure reducing state. On the other hand, when the duty value D is 0, the drain port is always shut off and the pressure level is maintained at the maximum pressure.

Further, the hydraulic pressure control circuit 60 includes a throttle modulator valve 89 and a second duty solenoid valve 90 for operating the valve for controlling the line pressure adjusted by the regulator valve 61.
Is provided.

A line 140 communicating with the control source pressure line 138 is led to the throttle modulator valve 89, and a second duty solenoid valve 90 that periodically opens and closes a control port 89a on one end side. The adjusted duty control pressure is introduced to generate the throttle modulator pressure according to the duty value D of the duty solenoid valve 90. In that case, the duty value D is set according to, for example, the throttle opening of the engine, and the throttle modulator pressure corresponding to this is increased by the first increase of the regulator valve 61 via the line 141. By being introduced into the pressure port 61a, the line pressure adjusted by the valve 61 is increased in accordance with the increase in the throttle opening. On the other hand, regulator valve 6
The second pressure increasing port 61b provided in
A line 142 branched from 12 is connected. As a result, the line pressure is further increased in the R range.

In this embodiment, the duty control pressure generated by the first duty solenoid valve 88 for adjusting the engagement force of the lockup clutch 26 is also supplied to the control port 91a of the modulator valve 91. It has become so. This modulator valve 9
1 adjusts the line pressure supplied from the main line 110 via the line 143 according to the duty control pressure from the first duty solenoid valve 88 to generate a modulator pressure, and the modulator pressure is generated by the line 144. Is supplied to the back pressure chamber 81a of the N-R accumulator 81 and the like.

A line 145 branched from the line 144 is connected to the control port 76a of the 3-4 control valve 76 on the 3-4 clutch line 120. Therefore, if the duty control of the first duty solenoid valve 88 is performed, the modulator pressure corresponding to the duty value D is increased.
1 and is introduced into the control port 76a of the 3-4 control valve 76, whereby the hydraulic pressure (3-4 clutch pressure) adjusted by the control valve 76 also corresponds to the duty value D. Is adjusted to the specified value.

On the other hand, this 3-4 control valve 76
Is provided with a pressure regulation blocking port 76b for blocking a pressure regulation (pressure reduction) operation at one end thereof, and the pressure regulation blocking port 76b is connected to the main line 110 via the switching valve 92 and the line 146. The pressure blocking line 147 is connected. When the pressure regulation blocking line 147 communicates with the line 146 through the switching valve 92, the line pressure of the main line 110 is supplied to the pressure regulation blocking port 76b of the 3-4 control valve 76, The pressure regulating operation of the control valve 76 is blocked.

That is, in the control port 92a on one end side of the switching valve 92, the orifice 87 in the control source pressure line 138 and the first duty solenoid valve 8 are provided.
8 is connected to the line 148, and the balance port 92b on the other end side is connected to the line 149 branched from the control source pressure line 138 on the upstream side of the orifice 87. Then, when the duty control pressure generated by the first duty solenoid valve 88 is equal to or higher than a predetermined value, the spool of the switching valve 92 is located on the left side in the drawing, and the pressure regulation blocking line 147 becomes the main line 110. Line 14 leading to
6 to the main line 11 via the line 146.
By supplying the line pressure of 0 to the pressure regulation blocking port 76b of the 3-4 control valve 76, the pressure regulation operation of the control valve 76 is blocked. On the other hand, when the duty control pressure generated by the first duty solenoid valve 88 falls below a predetermined value, the spool of the switching valve 92 overcomes the spring force and moves to the right side, whereby the pressure regulation prevention line 14 is reached.
7 is disconnected from the line 146.

Here, the switching valve 92 is connected to a line 150 which communicates with the pressure regulation blocking line 147 when the spool is located on the right side. This line 150 is guided to the fourth shift valve 82 for lockup control, and a line 151 leading to the main line 110 when the spool of the shift valve 82 is located on the right side.
It is designed to communicate with. That is, the fourth ON-OF
When the F solenoid valve 84 is turned on and the spool of the fourth shift valve 82 is located on the right side in the drawing to control the engagement force of the lockup clutch 26, the line pressure of the main line 110 is changed to the line 15
It is guided to the pressure regulation blocking line 147 via the first and fourth shift valves 82 and the line 150. The fourth
In the converter state in which the spool of the shift valve 82 is located on the left side, the line 150 communicates with the drain port provided in the shift valve 82.

The switching valve 92 has a drain line 1 which communicates with the servo apply line 117 when the spool of the first shift valve 63 is located on the right side.
51 is connected. And this drain line 15
1 is selectively communicated with two drain ports having different throttle amounts.

The above-mentioned third control source pressure line 115 is branched from the control source pressure line 138 on the upstream side of the switching valve 92, and this source pressure line 115 is connected to the third ON-OFF solenoid valve. The control port 65 a of the third shift valve 65 is reached via 68.

Here, in the first shift valve 63,
3-4 The pressure regulation prevention line 14 for the control valve 14
The line 152 branched from 7 is connected, and when the first ON-OFF solenoid valve 66 is turned on and the spool of the first shift valve 63 is located on the left side, the first back pressure chamber 73a is connected to the main line 110. Line 153 leading to the second back pressure chamber 73b of the 1-2 accumulator 73 to which the line pressure is constantly introduced;
It is configured to communicate with 52. Therefore,
When the line pressure is supplied to the pressure regulation blocking line 147, this line pressure is supplied via the lines 152 and 153 only when the spool of the first shift valve 63 is located on the left side. It is introduced into the second back pressure chamber 74b of 73.

Further, the servo apply line 117 leading to the apply port 45b of the servo piston 45a.
The timing control valve 72 installed on the line 118 leading to the 1-2 accumulator 73 from the timing control valve 72 has a control port 72a at one end thereof.
A line 154 branched from the 3-4 clutch line 120 is connected to the downstream side of the 3-4 control valve 76, and the ball valve 93 and the ball valve 93 are connected to the accumulation cut prevention port 72b provided on the other end side. The lock-up control valve 8 via the line 155.
The line 156 leading to the pressure regulation blocking line 139 for pressure regulation blocking of No. 3 is connected. A line 157 branched from the line 125 connected to the second shift valve 64 is connected to the intermediate port 72c provided in the intermediate portion of the timing control valve 72.

The timing control valve 72
The ball valve 93 connected to the line 156 leading to the accumulation cut-inhibiting port 72b is connected to the line 1 leading to the lock-up pressure regulating blocking line 139.
Located on the opposite side of 55, a line 158 branched from a line 150 provided between the switching valve 92 and the fourth shift valve 82 is connected.

In addition to the above configuration, this hydraulic control circuit 6
0 is equipped with a fifth shift valve 94 mainly used for adjusting the shift timing. The fifth shift valve 94 is a first bypass line 159 that bypasses the orifice 72 on the servo apply line 117.
And a second bypass line 160 that bypasses the one-way valve 80 on the reverse clutch line 130, and the pressure regulation blocking port 8 of the lockup control valve 83.
The control source pressure line 161 branched from the main line 110 is guided to the control port 94a on one end side while being installed so as to straddle the lockup pressure regulation prevention line 139 guided to 3b. Then, the fifth ON-OFF solenoid valve 95 installed in the control source pressure line 161 is turned on and off to turn on the fifth ON.
The spool position of the -OFF solenoid valve 95 is switched, and the first and second bypass lines 159 and 16 are switched.
0 and the pressure regulation prevention line 139 are opened or closed.

That is, when the fifth ON-OFF solenoid valve 95 is OFF and the spool of the fifth shift valve 94 is located on the right side in the drawing, the first bypass line 159 and the pressure regulation blocking line 139 are opened. On the other hand, the second bypass line 160 is cut off. At this time, the downstream portion of the second bypass line 160 is a line 129 provided with the one-way orifice 79.
And the reverse clutch line 130 or the reverse line 112 through the line 129. On the other hand, when the fifth ON-OFF solenoid valve 95 is turned on and the spool of the fifth shift valve 94 is moved to the left side in the drawing, the first bypass line 159 and the pressure regulation prevention line 139 are each blocked, and the second The bypass line 160 is opened.

Further, the first bypass line 159 is provided with a one-way orifice 96 located downstream of the fifth shift valve 94 for performing a throttling action in the hydraulic oil supply direction, and the fifth bypass valve 159 is provided. A normal orifice 97 is provided on the upstream side of the shift valve 94. In the branch line 162 branched from the first bypass line 159 on the upstream side of the orifice 97, the orifice 98 having a smaller throttle amount than the orifice 97 and the passage of hydraulic oil in the discharge direction are blocked. The one-way valve 99 is provided, and when the branch line 162 turns on the fifth ON-OFF solenoid valve 95 and the spool of the fifth shift valve 94 is located on the left side, the branch line 162 is more than the valve 94. The first bypass line 159 is joined on the downstream side.

Next, the low reducing valve 77 according to the characteristic part of the present invention will be described more specifically. That is, as shown in FIG. 3, this reducing valve 7
A control port 77a is formed on the right end side of 7, and a spool 77b inserted in the valve 77 is pressed to the left side by the biasing force of a spring 77c arranged on the right side. Further, the output port 77d communicating with the ball valve 78 is selectively communicated with the input port 77e located on the left side and the drain port 77f located on the right side by the axial movement of the spool 77b. ing. Furthermore, the spool 77b
A feedback port 77g is formed on the left side of the output port 77g. When the output pressure fed back to the feedback port 77g is lower than the set pressure regulated by the spring force of the spring 77c, the output port 77d is input. When communicating with the port 77e and the output pressure is larger than the set pressure,
Since the output port 77d communicates with the drain port f, the maximum output pressure is limited to the pressure corresponding to the set pressure. Then, the maximum value is adjusted according to the control pressure introduced into the control port 77a. In this case, in this embodiment, a line 1 branched from the output line 141 of the throttle modulator valve 89 led to the first pressure increasing port 61a of the regulator valve 61 with respect to the control port 77a.
Leading 63. Therefore, the second line pressure control
When the duty solenoid valve 90 is duty controlled, a modulator pressure corresponding to the duty value D is generated by the throttle modulator valve 89 and introduced into the control port 77a of the low reducing valve 77. Therefore, the low reverse brake pressure adjusted by the reducing valve 77 is also adjusted to a value corresponding to the duty value D.

Further, as shown in FIG. 4, the automatic transmission 10 has first to third ON-OFF solenoid valves 66 to 68 for gear shift control and a fourth ON-OFF for lockup.
A controller 200 for controlling the operation of the OFF solenoid valve 84, the first duty solenoid valve 88, the second duty solenoid valve 90 for adjusting the line pressure, and the fifth ON-OFF solenoid valve 95 is provided. This controller 200 includes a signal from a vehicle speed sensor 201 that detects the vehicle speed of the vehicle, and a throttle opening sensor 202 that detects the throttle opening of the engine.
Shift position sensor 20 for detecting a signal from the shift lever and a position (range) of a shift lever included in the automatic transmission 10.
3 and the like are input, and the operation of each solenoid valve is controlled in accordance with the operating state indicated by these signals and the driver's request.

Although the automatic transmission 10 according to this embodiment has the above-mentioned structure, as described above, the output pressure of the low reducing valve 77 is variably controlled by the second duty solenoid valve 90 for controlling the line pressure. It has become. In that case, the duty solenoid valve 90
Controlled by throttle modulator valve 89
The output pressure of is controlled by the operation of the controller 200 according to the flowchart shown in FIG.

That is, the controller 200 reads various signals in step S1 and then executes step S2 to determine whether or not the value of the flag F is set to 1. If NO is determined, the shift position sensor 2
It is determined whether or not the range indicated by the signal from 03 is the L range. If YES is determined, it is also determined whether or not the range is the L range last time (steps S3 and S4). That is, it is determined whether or not the range has just been switched to the L range. Then, when it is determined that the previous time is not in the L range, the routine proceeds to step S5, and it is determined whether or not the throttle opening θ indicated by the signal from the throttle opening sensor 202 is smaller than a predetermined value θo (opening substantially corresponding to the idle position). If it is determined YES, the countdown process of the timer is started in step S6, the value of the flag F is set to 1 in step S7, and then step S8 is executed to determine the value based on the vehicle speed V. The duty value D output to the second duty solenoid valve 90 is determined.

That is, the controller 200 applies the vehicle speed V indicated by the signal from the vehicle speed sensor 201 to the map of the target modulator pressure, which is set by using the vehicle speed as a parameter as shown in FIG. 6, and sets the corresponding value. The target modulator pressure Pt is read. Then, by applying this target modulator pressure Pt to the duty value map shown in FIG. 7, the corresponding value is determined as the duty value D. In this case, the target modulator pressure Pt is set to a characteristic that increases as the vehicle speed V increases, as shown in FIG. 6, so the duty value D becomes smaller as the vehicle speed V increases.

The controller 200 then proceeds to step S9.
Is executed to output a duty control signal to the second duty solenoid valve 90 according to the duty value D obtained in step S8, and the timer value T is decremented in step S10, and then the timer value T is set to 0 in step S11. When it is determined to be YES, the value of the flag F is reset in step S12, and when it is determined to be NO, the step S12 is skipped and the process returns.

On the other hand, when the controller 200 determines in step S2 that the value of the flag F is set to 1, it skips steps S3 to S7, moves to step S8, and executes the following steps.

When it is determined in step S3 that the range is not the L range, the controller 200 executes step S13 to execute normal line pressure control. That is, the controller 200 determines the duty value D so that the target line pressure set based on, for example, the throttle opening degree is realized, and the second duty solenoid valve 90 outputs the duty control signal according to the determined duty value D. Output to.

Next, the operation of the embodiment will be described.

Assuming that the automobile is running at the second speed in the D range, for example, as shown in FIG. 3, the spools 6 of the first to third shift valves 63, 64 and 65 are provided.
3b, 64b, and 65b are located on the left side, the left side, and the right side, respectively. In this case, the first shift valve 63
The line pressure of the forward line 111, which is guided to the drive line 111, is applied via the servo apply line 117 to the apply port 4 of the servo piston 45a in the 2-4 brake 45 (not shown).
5b will be supplied. The servo release line 122 communicating with the release port 45c of the servo piston 45a (not shown) communicates with the drain port 65c of the third shift valve 65.
5 has been fastened. At this time, the low reverse brake line 127 leading to the low reverse brake 46 is also connected to the drain port 65d of the third shift valve 65.
The brake 46 is in a released state.

In the D-speed 2nd speed running state, the driver operates the shift lever to shift the range to L.
If the operating range belongs to the 1st speed range of the L range, the solenoid pattern is switched from the 2nd speed pattern of the D range to the 1st speed pattern of the L range according to the conditions shown in Table 2 above. , First and third ON-OFF solenoid valves 66, 6
8 is turned off. Therefore, as shown in FIG. 8, the spools 63b and 65b of the first and third shift valves 63 and 65 move to the right and left sides, respectively. As a result, the line 125 communicating with the ball valve 78 via the low reducing valve 77 becomes
The line 12 connected to the ball valve 78 while being connected to the line 124 leading to the shift valve 64.
6 communicates with the low reverse brake line 127 that communicates with the low reverse brake 46.

Here, in the 1st speed pattern of the L range, the spool 64b of the second shift valve 64 is located on the left side, and the line 124 communicates with the line 123 leading to the forward line 111. Line pressure is introduced to the third shift valve 65 via the second shift valve 64, the first shift valve 63, the low reducing valve 77 and the ball valve 78, and is reduced via the low reverse brake line 127 in the open state. By being supplied to the reverse brake 46, the fastening operation of the brake 46 is started. In that case, if the shift operation is performed with the accelerator pedal released, the control port 77a of the low reducing valve 77 will be described.
The control pressure supplied to the vehicle is controlled according to the vehicle speed V.

That is, when the vehicle speed indicated by the signal from the vehicle speed sensor 201 is high, the duty value D output to the second duty solenoid valve 90 is set small,
Along with this, the throttle modulator pressure generated by the throttle modulator valve 89 becomes high, and the control pressure introduced to the control port 77a of the low reducing valve 77 via the output line 141 and line 163 of the valve 89. Will also be higher. Therefore, the maximum value of the output pressure of the low reducing valve 77 becomes high, and the output pressure is used as the low reverse brake pressure, and the ball valve 7
8, line 126 and low reverse brake line 12
It is supplied to the low reverse brake 46 via 7. As a result, as indicated by reference numeral (a) in FIG.
The shelf pressure level formed by the low reducing valve 77 becomes high, and the low reverse brake 46 is quickly engaged without unnecessarily slipping.

For the 2-4 brake 45 in the engaged state in the second speed state, the servo piston 45a
The servo apply line 117 that communicates with the apply port 45b of the above is communicated with the drain line 151 that communicates with the drain port of the switching valve 92 in the hydraulic control circuit 60 of FIG. .

On the other hand, when the vehicle speed indicated by the signal from the vehicle speed sensor 201 is low, the duty value D output to the second duty solenoid valve 90 is set to a large value and the throttle modulator valve 89 accordingly generates it. The throttle modulator pressure decreases, and the control pressure introduced to the control port 77a of the low reducing valve 77 also decreases. Therefore, the maximum value of the output pressure of the low reducing valve 77 becomes low, and the output pressure is supplied to the low reverse brake 46 as the low reverse brake pressure. As a result, as shown by the symbol (a) in FIG. 9, the shelf pressure level formed by the low reducing valve 77 is lowered, and the low reverse brake 46 is smoothly engaged. In this case, since the throttle modulator pressure for controlling the line pressure is guided to the control port 77a of the low reducing valve 77, there is an advantage that the shelf pressure can be precisely controlled according to the vehicle speed.

Moreover, since the low reducing valve 77 is arranged on the upstream side of the ball valve 78, the pressure reduced by the valve 77 is applied to the ball valve 78.
The shuttle ball 78a built into the disk has an advantage that the durability of the shuttle ball 78a and the separate plate is improved.

Further, during the shift operation to the R range, the hydraulic oil discharged from the main line 110 to the retreat line 112 passes through the line 112, the line 129, the ball valve 78, and the fourth shift valve 82. 126 leading to low reverse brake line 127
Therefore, even if the spool 77b of the low reducing valve 77 sticks in a state where the output port 77d and the drain port 77f are in communication with each other, the reverse stage can be reliably realized.

Next, another embodiment of the present invention will be described with reference to FIGS. Since the skeleton part of this embodiment is common to the above embodiment, the same reference numerals as those of the embodiment are used for the elements that do not need to be changed, and the drawings are also incorporated.

That is, in this embodiment, FIG.
As shown in, the line 125 connected to the first shift valve 63 is directly connected to the ball valve 78, and the low reverse brake line 12 led to the low reverse brake 46 from the third shift valve 65.
7 on the low reducing valve 7 according to this embodiment.
7'is installed.

The low reducing valve 77 'has a control port formed at an intermediate portion thereof, and a spool 77b inserted in the valve 77'.
Is pressed to the left side by receiving the biasing force of the spring 77c arranged on the right side. Further, the output port 77d communicating with the low reverse brake 46 is connected to the spool 7
7b moves in the axial direction so that the input port 77e located on the left side and the drain port 77f located on the right side
It is designed to communicate selectively with. Even in this case, the feedback port 77g is formed on the left side of the spool 77b, and the output pressure fed back to the feedback port 77g is
When the pressure is higher than the set pressure regulated by the spring force of the spring 77c, the output port 77d communicates with the drain port f, so that the maximum output pressure is limited to the pressure corresponding to the set pressure. Become.

Also in this embodiment, the line 163 branched from the output line 141 led from the throttle modulator valve 89 to the regulator valve 61 (not shown).
Is connected to the control port 77a of the low reducing valve 77 '.

Further, in this embodiment, the pressure increasing port 77h is formed on the right end side of the low reducing valve 77 ', and the reverse line 1 is formed at this pressure increasing port 77h.
A pressure boosting line 164 branched from 12 is introduced.
Therefore, when the range is set to the R range, a part of the line pressure introduced from the main line 110 to the retreat line 112 is supplied to the pressure increasing port 77h of the low reducing valve 77 'via the pressure increasing line 164. As a result, the maximum value of the output pressure of the valve 77 'is increased by that amount.

Further, in this embodiment, the throttle modulator pressure generated by the throttle modulator valve 89 is controlled by the operation of the controller 200 as follows in accordance with the flowchart shown in FIG. ing.

That is, the controller 200 reads various signals in step T1 and then executes step T2 to determine whether or not the value of the first flag F1 is set to 1, and when it is determined to be NO. In step T3, it is determined whether or not the value of the second flag F2 is set to 1 this time. If NO is determined, it is determined whether or not it is immediately after the N-R shift is performed based on the signal from the shift position sensor 203 by executing step T4, and Y
When it is determined to be ES, the process proceeds to step T5 to start the countdown process of the first timer, and at step T6, the value of the first flag F1 is set to 1, and then step T8 is executed to execute the above based on the throttle opening θ. The duty value D output to the second duty solenoid valve 90 is determined.

That is, the controller 200 applies the throttle opening θ indicated by the signal from the throttle opening sensor 202 to the map of the target modulator pressure, which is set in advance with the parameter of the throttle opening as shown in FIG. Then, the corresponding value is read out as the target modulator pressure Pt. Then, by applying the target modulator pressure Pt to the duty value map shown in FIG. 7, the corresponding value is determined as the duty value D.

The controller 200 then proceeds to step T8.
Is executed to output the duty control signal to the second duty solenoid valve 90 in accordance with the duty value D obtained in step T7, and the timer value T1 is decremented in step T9, and then the timer value T1 is set to 0 in step T10. If YES, the value of the flag F1 is reset in step T11, and if NO, the step T11 is executed.
Skip and return.

On the other hand, when the controller 200 determines NO in step T4, it determines whether or not the signal from the shift position sensor 203 is in the L range, as in the case of the above embodiment. Also L
It is determined whether or not it is in the range (steps T12 and T13).
That is, it is determined whether or not the range has just been switched to the L range. Then, when it is determined that the previous time is not in the L range, the routine proceeds to step T14, where it is determined whether the throttle opening θ indicated by the signal from the throttle opening sensor 202 is smaller than a predetermined value θo, and YES
When it is determined that the second timer countdown process is started in step T15, the second timer countdown process is started in step T16.
After the value of the flag F2 is set to 1, step T17 is executed to execute the second operation based on the vehicle speed V as in the above embodiment.
The duty value D output to the duty solenoid valve 90 is determined. Even in this case, the duty value D is set to a smaller value as the vehicle speed V increases. The initial value of the second timer is set to a value smaller than the initial value of the first timer.

The controller 200 then proceeds to step T1.
8 is executed and the duty value D obtained in step T17
According to the above, the duty control signal is output to the second duty solenoid valve 90, and the second timer value T2 is decremented in step T19.
At 0, it is determined whether or not the timer value T2 has become 0, and YE
When it is determined to be S, the value of the second flag F2 is reset in step T21, and when it is determined to be NO, the process skips step T21 and returns.

When the controller 200 determines in step T2 that the value of the first flag F1 is set to 1, the controller 200 proceeds to step T7 and executes the following steps, and in step T3 described above. When it is determined that the value of the second flag F2 is set to 1, the process proceeds to step T17 and the following steps are executed.

Also in this case, the controller 200
When it is determined in step T12 that the range is not the L range, step T22 is executed and normal line pressure control is executed.

Next, the operation of this embodiment will be described.

If the range is switched to the L range by the driver's operation of the shift lever in the 2nd speed running state of the D range as in the above embodiment, when the operating state belongs to the 1st speed range of the L range, As shown in Table 2, the solenoid pattern is switched from the second speed pattern of the D range to the first speed pattern of the L range, and the first and third ON-OFF solenoid valves 66 and 68 are turned off. Therefore, FIG.
As shown in FIG. 3, the spools 63b and 65b of the first and third shift valves 63 and 65 move to the right and left sides, respectively. As a result, the first shift valve 63
A line 125 communicating with the ball valve 78 communicates with a line 124 communicating with the second shift valve 64, while a line 126 connected with the ball valve 78.
However, it will communicate with the low reverse brake line 127 leading to the low reverse brake 46. In this case, if the shift operation is performed with the accelerator pedal released, the control pressure supplied to the control port 77a of the low reducing valve 77 'will be controlled according to the vehicle speed V. .

That is, when the vehicle speed V indicated by the signal from the vehicle speed sensor 201 is high, the shelf pressure level formed by the low reducing valve 77 'becomes high as shown by the symbol (c) in FIG. When V is low, the shelf pressure level formed by the low reducing valve 77 'becomes low as indicated by reference numeral (D) in the figure.

On the other hand, when the shift operation from the N range to the R range is performed, the spool 62a of the manual valve 62 is positioned in the state of FIG. 15, and the line pressure of the main line 110 moves to the retreat line 112. Will be supplied. And this line pressure is the backward line 1
12 and the reverse clutch line 130 and is guided to the reverse clutch 44, and a part thereof is also guided to the line 129, and the ball valve 78 and the line 126.
Through the third shift valve 65. And the third
When the ON-OFF solenoid valve 68 is OFF and the spool 65a of the third shift valve 65 is located on the left side in the drawing, it is guided to the low reverse brake line 127 and the low reducing valve on the line 127. The pressure is adjusted to a predetermined pressure at 77 'and then supplied to the low reverse brake 46. In this case, since the line pressure is supplied to the pressure increasing port 77h of the valve 77 ′ through the pressure increasing line 164, the shelf pressure level is relatively high as shown by the reference numeral (e) in FIG. Become higher.
Since the shelf pressure level is adjusted according to the throttle opening θ, the reverse gear can be realized without causing an excessive shock.

Moreover, since the low reverse brake pressure can be controlled by the low reducing valve 77 'even during the N-D shift, there is a practical advantage that an accumulator for alleviating the N-R shock is unnecessary.

In the above embodiment, the throttle modulator pressure guided to the regulator valve 61 is used as the control pressure for the low reducing valve 77 (77 '). The control pressure may be supplied to the low reducing valve 77 (77 ').

[0099]

As described above, according to the present invention, the hydraulic pressure controlled by the electromagnetic hydraulic control means for controlling the line pressure is supplied to the control port of the pressure reducing valve for the friction element for the engine brake such as the low reverse brake. Therefore, when the friction elements are fastened,
If the control pressure or line pressure of the regulator valve adjusted by the electromagnetic hydraulic control means is changed according to the vehicle speed, the output pressure generated by the pressure reducing valve also changes according to the vehicle speed. It is possible to effectively suppress the shock that occurs when the friction elements are fastened. Moreover, since the electromagnetic hydraulic control means is used for controlling the line pressure, the structure of the hydraulic control circuit in this type of automatic transmission is simplified.

Particularly, according to the second aspect of the invention, the control pressure supplied to the regulator valve is supplied as the control pressure for adjusting the output pressure of the pressure reducing valve to the friction element for engine braking. The output pressure of the pressure reducing valve can be precisely controlled, and the shock can be suppressed more effectively.

According to the third aspect of the invention, the friction element for engine braking is a low reverse brake which is fastened between the engine braking range on the low speed stage side and the reverse range, and the range is set in the hydraulic control circuit. First hydraulic oil is supplied when set to the engine braking range
An oil passage, a second oil passage to which the working oil pressure is supplied when set to the reverse range, and the first and second oil passages are selectively connected to the oil passage leading to the low reverse brake by the movement of the shuttle ball. In the automatic transmission provided with the switching valve, the pressure reducing valve is arranged on the first oil passage upstream of the switching valve, so that the spool of the pressure reducing valve sticks when shifting to the reverse range. Even if it does, the reverse stage is definitely achieved,
Since the depressurized pressure is introduced to the switching valve, there is a practical advantage that the durability of the shuttle ball and the separate plate forming the switching valve is improved.

On the other hand, according to the fourth aspect of the invention, since the pressure reducing valve is arranged on the downstream side of the switching valve, the fastening pressure supplied to the low reverse brake is controlled by the pressure reducing valve even during the shift operation to the reverse range. Not only can it be controlled by using it, but there is the actual benefit that an accumulator for forming the shelf pressure is unnecessary.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing a hydraulic control circuit of an automatic transmission according to an embodiment.

FIG. 3 is an enlarged view of a main part of a hydraulic control circuit in a second speed state.

FIG. 4 is a control system diagram for each valve in the hydraulic control circuit of FIG.

FIG. 5 is a flowchart showing low reverse brake pressure or line pressure control by a second duty solenoid valve in the embodiment.

FIG. 6 is an explanatory diagram of a map used in the control.

FIG. 7 is an explanatory diagram of a map similarly used in the control.

FIG. 8 is an enlarged view of a main part of a hydraulic control circuit during a 2-1 shift.

FIG. 9 is a time chart showing changes in low reverse brake pressure.

FIG. 10 is an enlarged view of a main part of a hydraulic control circuit showing another embodiment of the present invention.

FIG. 11 is a flowchart showing low reverse brake pressure or line pressure control by a second duty solenoid valve in the embodiment.

FIG. 12 is an explanatory diagram of a map used in the control.

FIG. 13 is an enlarged view of a main part of a hydraulic control circuit during the 2-1 shift of the embodiment.

FIG. 14 is a time chart diagram showing changes in the low reverse brake pressure in the embodiment.

FIG. 15 is an enlarged view of a main part of a hydraulic control circuit in the R range.

[Explanation of symbols]

 10 Automatic Transmission 46 Low Reverse Brake 60 Hydraulic Control Circuit 61 Regulator Valve 77 Low Reducing Valve 77a Control Port 78 Ball Valve 78a Shuttle Ball 89 Throttle Modulator Valve 90 Second Duty Solenoid Valve 97 Fifth Solenoid Valve 112 Backward Line 125 Line 126 Line 127 Low reverse brake line 129 Line 130 Reverse clutch line 141 Output line 163 Line 200 Controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinya Kamata 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (4)

[Claims] 1. A pressure reducing valve for reducing the engagement pressure supplied to the friction element for engine braking, and a line pressure are provided in a hydraulic control circuit, which has a friction element for engine braking that is engaged in an engine braking range. And a regulator valve for controlling the line pressure by electrically changing the control pressure applied to the regulator valve, and an electromagnetic hydraulic control means for controlling the line pressure. A hydraulic pressure control device for an automatic transmission, comprising: a control pressure supply means for supplying a hydraulic pressure controlled by operation to a control port for adjusting an output pressure in the pressure reducing valve. 2. The control pressure supply means is configured to distribute and supply the control pressure supplied to the regulator valve to the control port for adjusting the output pressure in the pressure reducing valve. Hydraulic control device for automatic transmission. 3. The engine brake friction element is a low reverse brake that is fastened between an engine brake range and a reverse range on the low speed stage side, the hydraulic control circuit comprising:
A first oil passage to which the working oil pressure is supplied when the range is set to the engine braking range, a second oil passage to which the working oil pressure is supplied when the range is set to the reverse range, and the first and second oil passages. When a switching valve for selectively communicating the passage with the oil passage leading to the low reverse brake by the movement of the shuttle ball is provided, the pressure reduction is performed by being located on the first oil passage upstream of the switching valve. The hydraulic control device for an automatic transmission according to claim 1, wherein a valve is provided. 4. The engine brake friction element is a low reverse brake that is engaged between an engine brake range and a reverse range on the low speed stage side, and a hydraulic control circuit includes:
A first oil passage to which the working oil pressure is supplied when the range is set to the engine braking range, a second oil passage to which the working oil pressure is supplied when the range is set to the reverse range, and the first and second oil passages. A switching valve for selectively communicating the passage with the oil passage leading to the low reverse brake by the movement of the shuttle ball, a pressure reducing valve on the oil passage leading to the low reverse brake downstream of the switching valve. 3. The hydraulic control device for an automatic transmission according to claim 1, wherein the hydraulic pressure control device is arranged.