JPH0560208A - Oil pressure control device for automatic transmission - Google Patents

Abstract

PURPOSE:To surely make an engine brake effective at a gear shift stage where the engine brake is required. CONSTITUTION:A check ball valve 700 is arranged so as to bypass a coast brake cut-off valve 500, which is controlled by a third solenoid valve S3 to selectively supply D range pressure to a third brake B3, so that L range pressure may be supplied to the third brake B3 via this check ball valve 700. Even when a failure is caused in the third solenoid valve S3 and the coast brake cut-off valve 500, the third brake B3 is surely engaged to enhance its durability.

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 controlling supply / discharge of hydraulic pressure to / from a friction engagement device in an automatic transmission for a vehicle.

[0002]

2. Description of the Related Art As is well known, an automatic transmission for a vehicle has a one-way clutch incorporated in a gear transmission to prevent a shift shock. When the direction in which the torque acts is switched to the opposite direction, that is, when the driven state is switched to the driven state, the one-way clutch is released and the engine braking is disabled. Therefore, generally, a friction engagement device capable of transmitting torque in both directions, such as a multi-disc brake, is provided in parallel with the one-way clutch, and the friction engagement device is engaged during engine braking.

A solenoid valve may be used as a means for controlling this type of so-called frictional engagement device for engine brakes. In the invention disclosed in Japanese Patent Laid-Open No. 62-159839, as a countermeasure against the failure of the solenoid valve. , The control valve hydraulic pressure is supplied directly from the manual valve to the shift valve that controls the supply and discharge of the hydraulic pressure to the frictional engagement device for the engine brake, and the shift valve is kept in a specific state where the engine brake is applied in a predetermined range. It is configured as follows.

[0004]

The electrical fail, however, has two modes: non-energized and normally energized, and the solenoid valve may be a mechanical fail in addition to the electrical fail. In the conventional device described above, for example, the hydraulic pressure sent to the friction engagement device for engine brake via the shift valve becomes low, and the effectiveness of the engine brake becomes unstable, which may reduce the durability of the friction engagement device. ..

The present invention has been made in view of the above circumstances, and an object thereof is to improve the durability of a friction engagement device for an engine brake.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a first range in which engine braking may not be effective at a predetermined low speed stage and an engine braking effect at the predetermined low speed stage. A first range pressure output from the manual valve when the first range is selected by a manual valve that selects at least two ranges including a second range to be controlled by an electronic means. In the hydraulic control device of the automatic transmission configured to supply to the friction engagement device for engine brake via
A switching valve mechanism is provided, which supplies the second range pressure output from the manual valve when the second range is selected by the manual valve, bypassing the valve to the friction engagement device for engine braking. It is characterized by that.

[0007]

The valve controlled by electrical means is arranged between the manual valve and the friction engagement device for engine braking, so that the first valve output from the manual valve when the first range is selected. Range pressure is supplied to the friction engagement device for engine braking through the valve,
On the other hand, on the contrary, the valve is blocked and is not supplied to the engine brake frictional engagement device. That is, in the hydraulic control device of the present invention, the engine brake can be activated or not activated while the first range is selected. On the other hand, when the second range is selected by the manual valve, the second range pressure output from the manual valve can be supplied to the engine brake friction engagement device via the switching valve mechanism.
It will bypass the valve. Therefore, when the second range is selected, the engine brake can be activated regardless of the electrical means for controlling the valve, and the supplied hydraulic pressure is also sufficient. The durability of the friction engagement device is improved.

[0008]

1 and 2 are hydraulic circuit diagrams showing an embodiment of the present invention, showing an automatic transmission including the hydraulic circuit. An example of the overall configuration is shown in FIG.

That is, the automatic transmission A connected to the engine E has a torque converter 21 having a lock-up clutch 20, a second speed change portion 30 having a set of planetary gear mechanisms, and two sets of planets as a transmission mechanism. A first transmission unit 40 that sets a plurality of forward gears and reverse gears by a gear mechanism is provided.

The second transmission section 30 is for performing two-stage switching between high and low. The carrier 31 of the planetary gear mechanism is connected to the turbine runner 22 of the torque converter 21, and the carrier 31 is also provided. Between the sun gear 32 and the sun gear 32, a clutch C0 and a one-way clutch Fo are provided in parallel relationship with each other.
A brake B0 is provided between the housing and the housing Hu.

The sun gears 41, 42 in each planetary gear mechanism of the first transmission unit 40 are provided on a common sun gear shaft 43, and in the planetary gear mechanism on the left side (front side) of the first transmission unit 40 in the drawing. Ring gear 44 and second
A first clutch C1 is provided between the gear unit 30 and the ring gear 33, and a second clutch C2 is provided between the sun gear shaft 43 and the ring gear 33 of the second gear unit 30. The carrier 45 of the planetary gear mechanism on the left side of the drawing and the ring gear 46 of the planetary gear mechanism on the right side (rear side) of the first transmission unit 40 are integrally connected, and
The output shaft 47 is attached to the carrier 45 and the ring gear 46.
Are connected.

The first brake B1 which is a band brake is provided on the outer peripheral side of the clutch drum of the second clutch C2 so as to stop the rotation of the sun gear shaft 43, more specifically, the sun gear shaft 43 and the housing. A first one-way clutch F1 and a second brake B2 are arranged in series with Hu, and a second one-way clutch F2 with a carrier 48 and a housing Hu in the planetary gear mechanism on the rear side. The third brake B3 is arranged in parallel.

A hydraulic circuit 50 for supplying and discharging hydraulic pressure to and from the clutches C0, C1 and C2 and the brakes B0, B1, B2 and B3 is provided. This hydraulic circuit 50
Is provided with first and second solenoid valves S1 and S2 for executing the first to fourth speed shifts, and a third solenoid valve S3 for engine braking.
An electronic control unit (ECU) 51 is provided to control on / off of these solenoid valves S1, S2, S3. The electronic control unit 51 is mainly composed of a central processing element, a storage element and an input / output interface, and has the solenoid valves S1, S2, S.
As data for controlling 3, the vehicle speed signal detected by the vehicle speed sensor 52, the throttle opening signal detected by the throttle opening sensor 53 attached to the engine E, various signals output from the shift lever device 54, and the power mode A pattern select signal output from the shift pattern selection switch 55 such as the economy mode and the economy mode, an engine water temperature signal detected by the water temperature sensor 56, a brake signal output from the foot brake switch 57 and the side brake switch 58, and the like are input. ..

The automatic transmission A described above is constructed so that it can be selected between an automatic mode and a manual mode. Here, the automatic mode is the gear shift in the forward gear,
This is a shift mode that is automatically executed based on the running state of the vehicle such as vehicle speed and engine load. In the manual mode, the shift lever device 54 is manually set to the manual shift position by selecting each shift stage in the forward shift stage. The shift lever device 54 is operated by operating the shift lever device 54. Therefore, the shift lever device 54, as shown in FIG. 3, includes parking (P), reverse (R), neutral (N), drive (D), and second (N).
Each range of the speed holding (S) and the first speed holding (L) and the manual shift positions of the first speed to the fourth speed can be selected by the shift lever, and the manual shift positions of the first speed to the fourth speed are shown in FIG. As shown in FIG. 5, the shift lever is moved from the D range position to the H-shaped arrangement. Further, the shift lever device 54 and the hydraulic control circuit 50 are connected by a link mechanism (not shown) in order to switch a manual valve which will be described later in accordance with the shift to the P range or the L range. A signal corresponding to the manual shift position is output to the electronic control unit 51.

In the above-described automatic transmission A, each gear is set by engaging each friction engagement device as shown in FIG. In FIG. 4, ◯ indicates ON for the solenoid valve, engagement for the friction engagement device, X indicates OFF for the solenoid valve, release for the friction engagement device, and Δ indicates the solenoid valve. Indicates that it can be switched to ON / OFF, and that the friction engagement device can be switched between engagement and disengagement as appropriate.

The hydraulic circuit shown in FIGS. 1 and 2 is incorporated in the hydraulic circuit 50 shown in FIG. 3, and includes a manual valve 100 for selecting a range and each shift valve 200,
In addition to 300 and 400, a coast brake cutoff valve 500 for controlling the supply and discharge of hydraulic pressure to and from the friction engagement device for engine brake is provided. 1 and 2
The circled numbers in indicate that the lines with the numbers are connected to each other.

In FIG. 1, a manual valve 100
By the shift lever device 54.
The primary regulator valve (not shown) is used to switch the hydraulic pressure supply / discharge state by moving the
Line pressure oil passage 60 for supplying the line pressure PL regulated by
Is connected to the input port 102, and in the D range, the spool 101 is in the position shown in the figure so that the input port 102 communicates with the D port 103. Also S
In the range, the spool 101 moves to the lower side of the figure and the input port 102 communicates with the D port 103 and the S port 104. In the L range, the spool 101 moves further to the lower side and the input port 102 moves to the D port 103. In the N range, the spool 101 closes the input port 102, and in the R range, the input port 102 communicates with the R port 106, and the S port 104 and the L port 105 communicate with each other.
In the P range, the input port 102 is closed and other ports are connected to the drain port.

The 1-2 shift valve 200 for shifting between the first speed and the second speed is a spool 2 having four lands.
01 and a spring 202 arranged at one end thereof, the control port 203 formed at the end opposite to the spring 202 is connected to the second solenoid valve S2, and when the second solenoid valve S2 is OFF. From the line pressure oil passage 61 to the strainer 62 and the orifice 63.
The line pressure PL supplied through the control port 203 is generated at the control port 203. Below the control port 203 in the drawing, a second coast port 204 that is opened and closed by the uppermost land, and a first brake port 206 that is selectively communicated with the second coast port 204 and the drain port 205 are sequentially arranged. The second coast modulator valve 64 is formed on the first brake port 206.
The first brake B1 is connected via. The manual valve 1 is located below the drain port 205 in the figure.
A D port 207 connected to the D port 103 of 00 is formed, and this D port 207 and another drain port 2
Second brake port 209 selectively connected to 08
The second brake B2 is connected to. Further another drain port 2 below the other drain port 208 in the drawing.
10 is formed, and the third brake B3 is connected to the third brake port 212 that selectively communicates with the drain port 210 and the low coast port 211. A hold port 213 is formed at the lowermost end where the spring 202 is arranged.

As shown in FIG. 2, a 2-3 shift valve 300 for shifting between the second speed and the third speed has a spool 301 having six lands and one end portion (the lower end portion in the drawing) of the spool 301. ), And the control port 3 formed at the end opposite to the spring 302.
03 is connected to the first solenoid valve S1, and when the first solenoid valve S1 is OFF, the line pressure PL supplied from the D port 103 of the manual valve 100 via the strainer 65 and the orifice 66 is supplied to the control port 303. It is supposed to work.

The 2-3 shift valve 300 includes a first drain port 304 and a brake port 3 in order from the top of the drawing.
05, D port 306 is formed, the brake port 305 is connected to the second coast port 204 of the 1-2 shift valve 200, and the brake port 305 is connected to the first drain port 304 and the D port 306. It is designed to communicate selectively. Following the above ports, a hold output port 307, an input port 308, a clutch port 309, and a second drain port 310 are sequentially formed, and the first drain port 304
And the brake port 305 communicate with each other, the D port 306, the hold output port 307, and the input port 3
08 and the clutch port 309 communicate with each other, and when the brake port 305 communicates with the D port 306, the hold output port 307 and the input port 308, and the clutch port 309 and the second drain port 310 communicate with each other. It has become. Further, following the second drain port 310, the brake port 311, the L port 31
2 are formed in order, and when the clutch port 309 communicates with the input port 308, the second drain port 3
10 communicates with the brake port 311, and conversely, when the clutch port 309 communicates with the second drain port 310, the brake port 311 and the L port 312 communicate with each other. Furthermore, spring 30
A hold port 313 is formed at the lowermost end where 2 is arranged.

The second clutch C2 is connected to the clutch port 309, while the 1-2 shift valve 2 is connected.
00 hold port 213 and this clutch port 30
9 and 9 are connected to each other. In addition, the brake port 31
1 through 1-2 via the low coast modulator valve 67
It is connected to the low coast port 211 of the shift valve 200.

The 3-4 shift valve 400 is controlled by the second solenoid valve S2 and the hydraulic pressure sent from the hold output port 307 of the 2-3 shift valve 300,
The second gear shifting unit 30 is configured to carry out gear shifting, and includes a spool 401 having four lands formed therein and a spring 402 arranged at one end thereof, and an end opposite to the spring 402. Control port 4 formed on
03 is connected to the second solenoid valve S2 similarly to the control port 203 of the 1-2 shift valve 200 described above, and the hold port 404 formed at the end where the spring 402 is arranged has a 2-3 shift. It is connected to the hold output port 307 of the valve 300. This 3-4 shift valve 400 has an input port 405 connected to the line pressure oil passage 61 when the second solenoid valve S2 is OFF and the line pressure PL is acting on the control port 403. , The brake B0 is connected to the connected brake port 406, and conversely, when the pressure is discharged from the control port 403 or when the hydraulic pressure acts on the hold port 404, the input port 4
05 is the clutch port 4 to which the clutch C0 is connected
It is designed to communicate with 07.

The first clutch C1 is connected to the D port 103 of the manual valve 100, and in the manual mode in the oil passage 68 from the first clutch C1 to the D port 306 of the 2-3 shift valve 300. In order to apply the engine brake between the first speed and the second speed of the vehicle, in other words, the coast brake cutoff valve 500 for preventing the engine brake between the first speed and the second speed in the automatic mode, and the switching. A first check ball valve 600, which is a valve mechanism, is provided. This coast brake cutoff valve 500 has a first clutch C.
The clutch port 501 connected to 1 and the brake port 50 connected to the first check ball valve 600
2 for selectively communicating with the spring 5
03 has a spool 504 that is pressed in one direction, and a third solenoid is attached to a control port 506 formed at the end opposite to the port 505 that is open at the end where the spring 503 is arranged. The valve S3 is connected. This third solenoid valve S3 is connected to the first clutch C.
1 and the control port 506 are connected to the oil passage 71 connecting the strainer 69 and the orifice 70,
In the FF state, the drain port is closed to generate hydraulic pressure in the control port 506, and in the ON state, the drain port is opened to exhaust the pressure from the control port 506.

As shown in FIG. 2, the first check ball valve 600 connected to the brake port 502 of the above coast brake cutoff valve 500 has two input ports 601 and 60 formed to face each other on the same axis.
The output port 603 is formed between two input ports, and the ball 604 is pushed by the hydraulic pressure input from any one of the input ports to close the other input port so that the one input port and the output port 603 are communicated with each other. It is composed. The brake port 502 of the coast brake cutoff valve 500 is connected to the first input port 601 through the oil passage 68, and the second input port 602 is connected to the S port 1 of the manual valve 100.
04 is connected, and the output port 603 is connected to the above-mentioned 2
-3 is connected to the D port 306 of the shift valve 300.

Coast brake cutoff valve 5
00 brake port 502 and manual valve 100
The L port 105 is connected to the 2-3 shift valve 30 via the second check pole valve 700 which is another switching valve mechanism.
It is connected to 0. That is, the second check ball valve 700 is the same as the first check ball valve 6 described above.
Similarly to 00, a pair of input ports 701 and 702, an output port 703 formed between these input ports 701 and 702, and a ball 704 that switches a communication state between the input ports 701 and 702 and the output port 703. And the brake port 502 of the coast brake cutoff valve 500 is connected to the first input port 701, the L port 105 of the manual valve 100 is connected to the second input port 702, and the output port 703 is 2-3 L port 312 of shift valve 300
And the hold port 313.

Since the first and second solenoid valves S1 and S2 are turned on or off as shown in FIG. 4, in the 1-2 shift valve 200, the spool as shown in the right half at the first speed. 201 is pushed down, the spool 201 is pushed up as shown in the left half of the figure at the other forward speeds, and in the 2-3 shift valve 300, as shown in the right half of the figure at the first speed and the second speed. Spool 3
01 is pushed up, and in the third and fourth gears, the spool 301 is pushed down as shown in the left half of the figure, and
In the 3-4 shift valve 400, the spool 401 is pushed up in the first speed to the third speed as shown in the right half of the figure,
In 4th gear, it is pushed down as shown in the left half of the figure. As a result, each friction engagement device is engaged or disengaged as shown in FIG. 4, and each gear stage is set.

Since the third solenoid valve S3 is ON / OFF controlled as shown in the table of FIG. 5, the first and second speeds S and S in the manual mode and the L range are controlled.
The engine brake will be activated at the second speed in the range. In FIG. 5, the meanings of the circles and the crosses are the same as those in FIG. 4 and 5, the manual mode is “manual” and the auto mode is “automatic”.
Is written.

Hereinafter, the first in each range and mode
The control for applying or not applying the engine braking at the second speed and the second speed will be described. First, the automatic mode in the state where the manual valve 100 selects the D range will be described. In this case, the third solenoid valve S3 is turned off in both the first speed and the second speed. Therefore, since the drain port of the third solenoid valve S3 is closed and the hydraulic pressure acts on the control port 506 of the coast brake cutoff valve 500, its spool 504 is pushed down to the position shown in the right half of FIG. Valve 1
Clutch port 5 connected to D port 103 of 00
01 is closed. Moreover, S of the manual valve 100
Since the port 104 and the L port 105 communicate with the drain port, the D port 306 of the 2-3 shift valve 300
No hydraulic pressure is sent to the or L port 312, and therefore the first brake B1 and the third brake B3 to which hydraulic pressure is supplied via these ports remain released. Ie D
The engine braking does not work in the first speed and the second speed in the automatic mode with the range selected.

On the other hand, in the first speed in the manual mode, the third solenoid valve S3 is turned ON when the vehicle speed is equal to or lower than a predetermined vehicle speed. In that case, the drain port of the third solenoid valve S3 is opened and the pressure is exhausted from the control port 506 of the coast brake cutoff valve 500.
04 is pushed up to the state shown in the left half of FIG. As a result, since the clutch port 501 and the brake port 502 are in communication with each other, hydraulic pressure is supplied to the L port 312 of the 2-3 shift valve 300 via the oil passage 68 and the second check ball valve 700. In the 2-3 shift valve 300, since the first solenoid valve S1 is ON and the pressure is exhausted from the control port 303, the spool 301 is pushed up to the state shown in the right half of FIG. The hydraulic pressure supplied to the port 312 is passed through the brake port 311 and the low coast modulator valve 67 to the low coast port 2 of the 1-2 shift valve 200.
11 is supplied. Then, in the 1-2 shift valve 200, the second solenoid valve S2 is turned off, and the hydraulic pressure acts on the control port 203, so that the spool 2
Since 01 is pushed down to the state shown in the right half of FIG. 1, the hydraulic pressure supplied to the low coast port 211 is supplied to the third brake B3 via the third brake port 212, and this is engaged. That is, since the third brake B3, which is arranged in parallel with the second one-way clutch F2 that applies a reaction force in the power-on state, is engaged, the engine brake can be activated.

Further, since the third solenoid valve S3 is turned on even in the second speed in the manual mode, the clutch port 501 and the brake port 502 of the coast brake cutoff valve 500 are in communication with each other, and the oil passage 68 and the first port are connected. Hydraulic pressure is supplied to the D port 306 of the 2-3 shift valve 300 via the check ball valve 600.
Since the spool 301 of the 2-3 shift valve 300 is pushed up to the position shown in the right half of the figure as in the case of the first speed, the hydraulic pressure of the D port 306 is 1-2 shifts via the brake port 305. It is sent to the second coast port 204 of the valve 200. In second gear, 1
The spool 201 of the -2 shift valve 200 is in the state shown in the left half of FIG. 1 because the spool 201 is exhausted from the control port 203, and therefore the second coast port 20
4 communicates with the first brake port 206, and as a result, hydraulic pressure is supplied to the first brake B1 via the second coast modulator valve 64, and this is engaged. That is, the first brake B arranged in parallel with the first one-way clutch F1 that applies a reaction force in the power-on state of the second speed.
When 1 is engaged, engine braking can be activated.

Explaining the S range, the third solenoid valve S3 is turned off in the first speed of the S range, so that the coast brake cutoff valve 500 pushes down the spool 504 to the position shown in the right half of FIG. As a result, the clutch port 501 is cut off, so that the hydraulic pressure is not supplied through the oil passage 68. However, when the S range is selected, the S port 104 of the manual valve 100 communicates with the input port 102, and this S port 104 is connected to the second input port 602 of the first check ball valve 600. Is supplied to the D port 306 of the 2-3 shift valve 300 via the first check ball valve 600, and is further sent to the second coast port 204 of the 1-2 shift valve 200 via the brake port 305. Since the second coast port 204 is closed at the first speed, the hydraulic pressure is not supplied to the first brake B1.

On the other hand, in the second speed of the S range, the third speed
The solenoid valve S3 is turned on, so that the hydraulic pressure is supplied to the first brake B1 and is engaged in the same manner as in the case of the second speed in the manual mode described above. That is, the engine brake comes to work.

At the second speed in the S range, there is some abnormality in the third solenoid valve S3 or the coast brake cutoff valve 500, and the hydraulic pressure sent through the oil passage 68 is low or the hydraulic pressure is not sent. If not, the ball 604 is pushed downward in FIG. 2 by the hydraulic pressure input from the second input port 602 in the first check ball valve 600. Therefore, in the case of such an abnormality, the manual valve 100
The hydraulic pressure (S range pressure) output from the S port 104 of the first check ball valve 600, the 2-3 shift valve 300, and the 1-2 shift valve 200
Since the hydraulic pressure is supplied to the brake B1 and the line pressure is a normal pressure, the first brake B1 is reliably engaged and the durability is prevented from lowering.

The case where the L range is selected will be further described. The third solenoid valve S3 is turned on in both the first speed and the second speed in the L range.
Therefore, the 1-2 shift valve 200 has a second coast port 211 and a second coast port 204 which have a second
Check ball valve 700 and 2-3 shift valve 3
00 or the first check ball valve 60
Since the hydraulic pressure is sent through the 0 and 2-3 shift valves 300, in the case of the first speed, the low coast port 211 communicates with the third brake port 212 and the hydraulic pressure is supplied to the third brake B3. In the case of high speed, the second coast port 204 communicates with the first brake port 206 and hydraulic pressure is supplied to the first brake B1. As a result, the first
The engine braking is effective at any one of the first speed and the second speed.

When the L range is selected, in the manual valve 100, the D port 103, the S port 104,
Since each of the L ports 105 communicates with the input port 102, in the first check ball valve 600, the S port 1 of the manual valve 100 is connected to the second input port 602.
The hydraulic pressure (S range pressure) from 04 is supplied, and in the second check ball valve 700, the second input port 7
The oil pressure (L range pressure) from the L port 105 of the manual valve 100 is supplied to 02. Therefore, when the third solenoid valve S3 or the coast brake cutoff valve 500 has some abnormality at the first speed in the L range and the oil pressure in the oil passage 68 is lowered, the L range pressure is set to the second check ball valve 700. Since it is sent to the L port 312 of the 2-3 shift valve 300 via the second input port 702 and the output port 703, the spool 301 and the 1-2 shift valve 200 of the 2-3 shift valve 300.
Since the spools 201 are in the states shown in the right half of the figure, the hydraulic pressure is supplied to the third brake B3 and the third brake B3 is engaged. That is, even if there is an abnormality in the third solenoid valve S3 or the coast brake cutoff valve 500, the hydraulic pressure of the necessary and sufficient pressure is reliably sent to the third brake B3, so that the third brake B3 is engaged without slipping. , Its durability is improved. The same applies to the case of the second speed, and when the L range is selected, the first speed is set.
Second input port 602 of check ball valve 600
When the oil pressure in the oil passage 68 is low, the S range pressure is applied to the first check ball valve 6 because
00 from the second input port 602 through the output port 603 to the D port 306 of the 2-3 shift valve 300. In the second speed, the spool 301 of the 2-3 shift valve 300 is in the state shown in the right half of FIG.
Since the spool 201 of the shift valve 200 is in the state shown in the left half of FIG. 1, the hydraulic pressure is supplied to the first brake B1 to engage it. That is, the third solenoid valve S
Even if there is an abnormality in 3 or the coast brake cutoff valve 50, the hydraulic pressure of the necessary and sufficient pressure is reliably sent to the first brake B1, so the first brake B1 is engaged without slipping and the durability is improved. To do.

6 and 7 are hydraulic circuit diagrams showing another embodiment of the present invention. In the example shown here, the arrangement of the second check ball valve 700 is described above with reference to FIGS. 1 and 2.
It is different from the example shown in, and some changes are made. That is, the second check ball valve 7
The output port 703 of 00 is L of the 2-3 shift valve 300.
Only the port 312 is connected, and the L port 105 of the manual valve 100 is a 2-3 shift valve 30.
0 hold port 313 and second check ball valve 700 second input port 702. Therefore, in the embodiment shown in FIGS. 6 and 7, unlike the above-mentioned embodiment, the D port 1 of the manual valve 100 is different.
The hydraulic pressure output from 03 is applied to the coast brake cutoff valve 500 and the second check ball valve 700.
2-3 Hold port 313 of shift valve 300
When the vehicle is traveling at the fourth speed in the D range, the spool 504 of the coast brake cutoff valve 500 is changed from the state shown in the right half of the figure due to an abnormality in the third solenoid valve S3. Even if it suddenly switches to the state shown in the left half, 2-3 shift valve 30
0 spool 301 does not switch from the third speed / fourth speed state shown in the left half of the figure to the first speed / second speed state shown in the right half of the figure, and the spool of 3-4 shift valve 400 Since the 401 does not switch from the fourth speed state shown in the right half of the figure to the first speed to the third speed state, the downshift from the fourth speed to the first speed due to the abnormality of the third solenoid valve S3. Can be prevented in advance. The other operations of the embodiment shown in FIGS. 6 and 7 are the same as those of the embodiment shown in FIGS. 1 and 2 described above.

In the above embodiment, an example in which the shift lever device in which the first-speed to the fourth-speed manual shift positions are arranged in an H shape is adopted is explained, but the shift lever which can be used in the present invention is explained. The device is not limited to the one shown in the above embodiment, and may be configured to upshift or downshift one step each time the shift lever is operated in a predetermined direction.

The present invention can also be applied to a hydraulic control system for an automatic transmission having a gear train other than the gear train shown in the skeleton diagram of FIG.

[0039]

As described above, according to the hydraulic control system of the present invention, in the range where the engine brake is effective in the low speed stage, the friction for the engine brake is not required even through the valve controlled by the electric means. Since the hydraulic pressure can be supplied to the engagement device, it is possible to reliably engage the engine brake friction engagement device at a shift speed that requires engine braking and improve its durability.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing a part of a hydraulic circuit of a hydraulic control device according to the present invention.

FIG. 2 is a hydraulic circuit diagram showing another portion of the hydraulic circuit of the hydraulic control device according to the present invention.

FIG. 3 is a schematic configuration diagram showing an overall configuration of an automatic transmission.

FIG. 4 is an operation table.

FIG. 5 is a table showing ON / OFF states of solenoid valves for controlling the coast brake cutoff valve and engagement / release states of the first brake and the third brake.

FIG. 6 is a hydraulic circuit diagram showing a part of a hydraulic circuit of another hydraulic control device according to the present invention.

FIG. 7 is a hydraulic circuit diagram showing another portion of the hydraulic circuit of another hydraulic control device according to the present invention.

[Explanation of symbols]

 100 Manual valve 500 Low coast brake cut-off valve 600 1st check ball valve 700 2nd check ball valve B1 1st brake B2 2nd brake B3 3rd brake S3 3rd solenoid valve

Front Page Continuation (72) Inventor Takayuki Okada 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (72) Inventor Takeshi Inukazuka 10 Takane, Fujii-cho, Aichi-prefecture Aisin A / D Abri (72) Inventor Masashi Hattori 10 Akane Takane, Fujii-cho, Aichi Prefecture Aisin A-Daburi Co., Ltd.

Claims (1)

[Claims] 1. A manual valve for selecting at least two ranges, a first range in which engine braking may not be applied at a predetermined low speed stage and a second range in which engine braking may be applied at a predetermined low speed stage. A hydraulic control device for an automatic transmission configured to supply the first range pressure output from the manual valve when the first range is selected to the engine brake friction engagement device via the valve, wherein the manual valve When the second range is selected by, a switching valve mechanism is provided for supplying the second range pressure output from the manual valve to the engine brake friction engagement device, bypassing the valve. Hydraulic control device for automatic transmission.