JP2002168330A - Hydraulic control device of automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device of an automatic transmission considering the downsizing of the device and the fail-safe for achieving safety. SOLUTION: A fail-safe hydraulic circuit 15 has a first open/close valve 17 for feeding/cutting a C1 feed pressure from a hydraulic control unit 9 to a C1 clutch 7a, a first check valve 19 connected in parallel to the first open/ close valve 17 for feeding the C1 feed pressure to the C1 clutch 7a, bypassing the first open/close valve 17, when the first open/close valve 17 is fastened in a closed state, and a fine orifice 21 for dropping the oil pressure inside the C1 clutch 7a down to a drain. In the fail-safe oil pressure circuit 15, a hydraulic passage for feeding the oil pressure from the hydraulic control unit 9 to the C1 clutch 7a is communicated at ordinary time. When the engine is stopped, the hydraulic control unit 9 and the C1 clutch 7a are separated and the oil pressure from a motor-driven hydraulic pump 11 is fed to the C1 clutch 7a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device used for automatic engine stop / start control for saving fuel and improving exhaust emission by executing automatic stop and automatic start of an engine at an intersection, for example. More particularly, the present invention relates to a hydraulic control device for an automatic transmission used in a vehicle having a hydraulic automatic transmission.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic control device for a vehicle for automatically stopping and starting an engine, for example, Japanese Unexamined Patent Publication No.
As disclosed in Japanese Patent Application Laid-Open No. 177, in order to suppress a shock (due to an increase in hydraulic pressure) generated from the hydraulic automatic transmission when the engine is restarted after the automatic stop of the engine, the hydraulic pressure is increased by an electric hydraulic pump or the like while the engine is stopped. Is known.

[0003] In the vehicle hydraulic control apparatus having the above-described structure for automatically stopping and starting the engine, the required flow rate can be reduced by connecting an electric hydraulic pump immediately before a manual valve that switches between forward and backward. However, in the case of this hydraulic control device, each shift control valve and each clutch / brake are arranged downstream of the manual valve, and there is a place where hydraulic pressure leaks due to this. Therefore, the electric hydraulic pump is located upstream of the manual valve. Even if is connected, reducing the required flow rate is limited.

[0004] On the other hand, as another technique, an electric hydraulic pump is connected immediately before a hydraulic supply destination such as a starting clutch, and a hydraulic control unit upstream of a connection portion of the electric hydraulic pump supplies oil to the hydraulic supply destination. Devices for providing an on-off valve in a road have been studied. In the case of this hydraulic control device, the required flow rate can be made extremely small because each shift control valve is not interposed in the middle.

[0005]

However, if the on-off valve is locked (the valve body is fixed) in a closed state, the operation of the original transmission may be hindered. For example, the vehicle cannot be started due to the inability to supply hydraulic pressure to the clutch of the automatic transmission, the creep occurs in neutral due to the inability to release the hydraulic pressure from the clutch, or the internal lock of the transmission due to inappropriate hydraulic pressure (that is, inappropriate Malfunctions such as a combination of gears) may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to reduce transmission shock at the time of restarting an engine, for example, when performing automatic engine stop and start, and to reduce the required flow rate. It is an object of the present invention to provide a hydraulic pressure control device for an automatic transmission that does not impair the original function of the transmission even when the device configuration such as a small hydraulic pump is provided and the on-off valve is locked in a closed state.

[0007] That is, an object of the present invention is to provide a hydraulic control apparatus for an automatic transmission in which fail-safe operation is realized, which realizes downsizing of the apparatus and ensures safety.

[0008]

(1) In the hydraulic pressure control device for an automatic transmission according to the first aspect of the present invention, a friction engagement element (for example, a clutch or a brake) of the automatic transmission and the first fluid are controlled. A first on-off valve for opening and closing the hydraulic path is disposed in a hydraulic path between the pressure generating means (for example, a mechanical hydraulic pump driven by an engine). When the engine is driven, the first hydraulic pressure generating means supplies the hydraulic pressure to the friction engagement element via the first on-off valve, and when the engine is stopped, the first on-off valve is closed and the second hydraulic pressure is generated. The hydraulic pressure is supplied to the friction engagement element by means (for example, an electric hydraulic pump).

In particular, in the present invention, when the first on-off valve is fixed (locked) in a closed state, when the engine is driven (for example, when the engine is restarted), the first fail-safe mechanism (for example, Supply hydraulic pressure to the friction fastening element (bypassing the first on-off valve). Therefore, in the present invention, for example, transmission shock at the time of restarting the engine is reduced by supplying the hydraulic pressure to the friction engagement element which is minimum necessary for starting while the engine is stopped from the second hydraulic pressure generating means. Can be.

Further, in the present invention, the hydraulic pressure control unit which easily causes hydraulic pressure leakage (adjusts the supply state of the hydraulic pressure to the frictional engagement element) is not required to be disposed downstream of the second hydraulic pressure generating means. Therefore, the required flow rate is reduced, and the second hydraulic pressure generating means can be reduced in size. Further, in the present invention, for example, a hydraulic circuit (first fail-safe mechanism) is configured so that hydraulic pressure can be supplied to a clutch or the like bypassing the first on-off valve (for example, via a first check valve described later). By doing so, it is possible to supply hydraulic pressure to the clutch and the like even if the first on-off valve is locked in a closed state. As a result, the supply of the hydraulic pressure to the clutch and the like is not interrupted, and the running of the vehicle is not hindered.

(2) In the hydraulic control apparatus for an automatic transmission according to the second aspect of the present invention, a friction engagement element (eg, clutch or brake) of the automatic transmission and first hydraulic pressure generating means (eg, driven by an engine) A first on-off valve for opening and closing the hydraulic path is disposed in a hydraulic path between the first hydraulic valve and the mechanical hydraulic pump. When the engine is driven, the first hydraulic pressure generating means supplies the hydraulic pressure to the friction engagement element via the first on-off valve, and when the engine is stopped, the first on-off valve is closed and the second hydraulic pressure is generated. The hydraulic pressure is supplied to the friction engagement element by means (for example, an electric hydraulic pump).

In particular, in the present invention, when the first on-off valve is fixed (locked) in a closed state, the hydraulic pressure is applied from the frictional engagement element (for example, bypassing the first on-off valve) by the second fail-safe mechanism. Can be omitted. Therefore, according to the present invention, similarly to the first aspect of the invention, the transmission shock at the time of restarting the engine can be reduced, and the size of the second hydraulic pressure generating means can be reduced.

Further, in the present invention, for example, the hydraulic circuit (second fail-safe mechanism) is configured so that the hydraulic pressure can be released (dropped) from the clutch or the like bypassing the first on-off valve. 1 Even if the on-off valve is locked in the closed state, the hydraulic pressure can be released from the clutch or the like. As a result, it is possible to prevent the occurrence of creep in neutral (which causes an undesired vehicle start) and the internal lock of the transmission due to inappropriate hydraulic pressure.

The second fail-safe mechanism includes not only a structure bypassing the first on-off valve, but also a first fail-safe mechanism.
A configuration in which a minute orifice is provided in the flow path when the on-off valve is closed may be adopted. In this case, even if the first on-off valve is locked in the closed state, it is possible to release the hydraulic pressure from the clutch or the like via the minute orifice.

(3) The invention of claim 3 is provided with the configuration of the invention of claim 1 and the invention of claim 2, and accordingly, the invention of claim 1 and the invention of claim 2 is provided. It has both effects. That is, in the present invention, when the first on-off valve is fixed in the closed state, the first fail-safe mechanism supplies the hydraulic pressure to the friction engagement element (for example, bypassing the first on-off valve). In addition, the hydraulic pressure can be released from the friction engagement element (for example, bypassing the first on-off valve) by the second fail-safe mechanism.

(4) According to the fourth aspect of the present invention, as the first fail-safe mechanism, the first hydraulic pressure generating means (or a hydraulic control unit downstream thereof) and the friction engagement element are connected in parallel with the first on-off valve. A first check valve is interposed in the hydraulic path between the first hydraulic valve and the first check valve. Flow is prohibited.

That is, in the present invention, since the first check valve is arranged in parallel with the first on-off valve, even if the first on-off valve is fixed in the closed state, the first hydraulic pressure generating means is driven. By doing so, it is possible to supply hydraulic pressure to the friction engagement element via the first check valve (bypassing the first on-off valve).

(5) In the invention of claim 5, a minute orifice is interposed between the friction fastening element and the drain as the second fail-safe mechanism. Therefore, even when the first on-off valve is fixed in the closed state, the hydraulic pressure can be released from the frictional engagement element through the minute orifice (bypassing the first on-off valve).

Since the second fail-safe mechanism is a small orifice, it supplies a predetermined hydraulic pressure to the friction engagement element when the first hydraulic pressure generating means supplies the hydraulic pressure to the friction engagement element. There is no hindrance to doing so. That is, since the hydraulic pressure dropped through the minute orifice is very small, the hydraulic pressure supplied from the second hydraulic pressure generating means and the hydraulic pressure control unit are not all dropped, so that the normal operation is not affected.

(6) In the invention of claim 6, as the second fail-safe mechanism, the first hydraulic pressure generating means (or a hydraulic control unit downstream thereof) and the frictional engagement element are connected in parallel with the first on-off valve. A hydraulic pressure switching valve is interposed in the intervening hydraulic pressure path, and the hydraulic pressure switching valve switches between a state in which the hydraulic pressure from the friction engagement element is released and a state in which the hydraulic pressure is not released.

Therefore, even if the first on-off valve is stuck in the closed state, the hydraulic pressure switching valve can be operated to release the hydraulic pressure from the frictional engagement element (bypassing the first on-off valve). In particular, for example, if a hydraulic pressure switching valve is arranged in place of the micro orifice, the hydraulic pressure can be leaked only when the clutch hydraulic pressure or the like is unnecessary, instead of constantly leaking the hydraulic pressure. Efficient use is possible.

(7) According to the seventh aspect of the present invention, the hydraulic pressure switching valve is provided with a hydraulic pressure from the first hydraulic pressure generating means (or a hydraulic control unit downstream thereof) or a hydraulic pressure from the second hydraulic pressure generating means. Open and close by sensing the fluid pressure. Therefore, for example, when the hydraulic pressure is supplied from the hydraulic control unit (therefore, the first hydraulic pressure generating means), the hydraulic switching valve is operated by the increased hydraulic pressure, and the hydraulic pressure of the friction engagement element is increased. Can be set to be held. Conversely, when the hydraulic pressure is not supplied from, for example, the hydraulic pressure control unit (accordingly, the first hydraulic pressure generating means), the hydraulic pressure is reduced, and the hydraulic pressure switching valve is operated, so that the hydraulic pressure is reduced from the frictional engagement element. Can be set to pull out.

Further, for example, when the hydraulic pressure is supplied from the second hydraulic pressure generating means, the hydraulic pressure of the frictional engagement element can be set to be maintained by the increased hydraulic pressure.
Conversely, when the hydraulic pressure is not supplied from the second hydraulic pressure generating means, a state in which the hydraulic pressure is released from the friction engagement element can be set.

(8) In the invention according to claim 8, the first fail-safe mechanism and / or the second fail-safe mechanism may include:
In parallel with the first on-off valve, a second on-off valve is interposed in a hydraulic path between the first hydraulic pressure generating means (or a hydraulic control unit downstream thereof) and the frictional engagement element. The hydraulic path can be opened and closed by the on-off valve.

Therefore, when the first on-off valve is fixed in the closed state, the second on-off valve is opened to operate the first hydraulic pressure generating means, thereby bypassing the first on-off valve and closing the second on-off valve. Via this, hydraulic pressure can be supplied to the friction engagement element. Further, when the first on-off valve is stuck in the closed state, the second on-off valve is opened to stop the first hydraulic pressure generating means or the second hydraulic pressure generating means, thereby bypassing the first on-off valve and removing the first on-off valve. The hydraulic pressure can be released from the friction engagement element via the two-way valve.

(9) According to the ninth aspect of the present invention, the second check valve is interposed between the second hydraulic pressure generating means and the frictional engagement element downstream of the first on-off valve. With the second check valve,
The supply of the hydraulic pressure from the second hydraulic pressure generating means side to the friction fastening element side is permitted, and the supply in the opposite direction is prohibited.

(10) According to the tenth aspect of the present invention, the hydraulic control unit is provided between the first hydraulic pressure generating means and the frictional engagement element, and the hydraulic control unit provides the hydraulic control unit with the hydraulic control unit. The pressure supply condition can be adjusted. (10) According to the eleventh aspect, the first on-off valve, the first check valve, the hydraulic switching valve, the second on-off valve, and the like are interposed between the hydraulic pressure control unit and the friction engagement element. .

Therefore, in this case, the fluid pressure from the first fluid pressure generating means is adjusted by the fluid pressure control unit, and the first on-off valve, the first check valve, the fluid pressure switching valve, the second on-off valve, It will be supplied to the valve side. (12) In the twelfth aspect, the above-described hydraulic control apparatus for an automatic transmission is mounted on a vehicle that controls automatic stop and automatic start of an engine.

Therefore, by controlling the hydraulic pressure of the automatic transmission in conjunction with the automatic stop and automatic start of the engine, the above-described hydraulic shock required when the engine is restarted and the hydraulic pressure required for the clutch of the automatic transmission are reduced. Problems such as the inability to start the vehicle due to the inability to supply, the occurrence of creep in neutral due to the inability to release the hydraulic pressure from the clutch or the like, and the internal lock of the transmission due to inappropriate hydraulic pressure can be effectively prevented.

(13) The invention of claim 13 exemplifies the first on-off valve and the second on-off valve. Here, an electromagnetic on-off valve can be adopted as the first on-off valve and the second on-off valve. (14) The invention of claim 14 exemplifies an automatic transmission. Here, a planetary gear type automatic transmission (operated by hydraulic pressure) can be adopted.

The first on-off valve and the second on-off valve not only open and close the hydraulic path completely, but also, for example, in a closed state, unless the operation and effect of the present invention are greatly impaired. A structure in which a flow path is opened is also within the scope of the present invention. The second hydraulic pressure generating means only needs to maintain the hydraulic pressure, and may be an accumulator, an electric hydraulic pump, or a combination of an accumulator and an electric hydraulic pump.

Further, the degree to which the hydraulic pressure is released by the minute orifice is smaller than the flow rate supplied to the friction engagement element (for example, the C1 clutch).

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a hydraulic control device for an automatic transmission according to the present invention will be described below in detail with reference to the drawings by way of examples (embodiments). (Embodiment 1) A hydraulic pressure control device (hydraulic control device) for an automatic transmission according to the present embodiment is mounted on a vehicle that controls automatic stop and start of an engine, and the automatic transmission (automatic transmission; AT) is a planetary gear type automatic transmission operated by hydraulic pressure.

A) First, the schematic structure of the hydraulic control device for an automatic transmission according to the first embodiment will be described with reference to FIG. FIG.
FIG. 3 is an explanatory diagram showing a basic configuration of the automatic transmission. As shown in FIG. 1, a hydraulic automatic transmission 1 mounted on a vehicle that performs engine automatic stop / start control includes a mechanical hydraulic pump 5 driven by an engine 3 and a hydraulic pressure supplied from the mechanical hydraulic pump 5. And a hydraulic control unit 9 for switching hydraulic pressure supply to each of the friction engagement elements 7a to 7f (based on a command from an ECU (not shown)), and an electric hydraulic pump 11 for driving and supplying hydraulic pressure when the engine is automatically stopped.
And a second check valve 1 downstream of the electric hydraulic pump 11 for preventing hydraulic oil from flowing back to the electric hydraulic pump 11.
3 and a later-described fail-safe hydraulic circuit 15 provided between the hydraulic control unit 9 and a C1 clutch (start clutch) 7a, which is coupled when the vehicle starts.

Here, the frictional engagement element includes a C1 clutch 7a, a C2 clutch 7b, a C3 clutch 7c, which is a device for transmitting power by bringing power transmission members (not shown) into contact with each other, and a power transmission member (not shown). B which is a device for reducing the number of rotations of the power transmission member by contacting the fixed member
1 brake 7d, B2 brake 7e, B3 brake 7f
Is mentioned.

B) Next, the fail-safe hydraulic circuit 15, which is a main part of the hydraulic control device, will be described with reference to FIG. FIG. 2 is an explanatory diagram showing the fail-safe hydraulic circuit 15 and the like. As shown in FIG. 2, the fail-safe hydraulic circuit 15 is provided by the hydraulic control unit 9 and the C1 clutch 7.
a solenoid on-off valve (first on-off valve) 17 for supplying and shutting off the hydraulic pressure (C1 supply pressure) to the valve a, and the first on-off valve 17 when the first on-off valve 17 is fixed (locked) in a closed state. A first check valve 19 for supplying the C1 supply pressure to the C1 clutch 7a by bypassing the C1 clutch, and a minute orifice 21 capable of reducing the oil pressure in the C1 clutch 7a to the drain.

As will be described later in detail, the fail-safe hydraulic circuit 15 normally communicates a circuit (hydraulic path) so as to supply the hydraulic pressure from the hydraulic control unit 9 to the C1 clutch 7a, while stopping the engine. Sometimes, the hydraulic control unit 9 and the C1 clutch 7a are separated from each other, and the circuit operates to supply the hydraulic pressure from the electric hydraulic pump 11 to the C1 clutch 7a.

The first opening / closing valve 17 is a normally open valve that connects a hydraulic path by a spring when power is not supplied and shuts off the hydraulic path when power is supplied. Further, the first check valve 19 is a check valve connected in parallel with the first opening / closing valve 17 and permitting only the supply of the C1 supply pressure from the hydraulic control unit 9 to the C1 clutch 7a.

C) Next, the operation of the hydraulic control device of this embodiment will be described. First, the normal operation of the hydraulic control device will be described. When the C1 supply pressure is supplied from the hydraulic control unit 9 by the operation of the mechanical hydraulic pump 5, the first open / close valve 17 is normally open.
It is supplied to one clutch 7a.

At this time, although there is some leakage of hydraulic oil from the micro orifice 21, there is not enough leakage to drop all the hydraulic pressure of the C1 clutch 7a, so that the C1 clutch 7a can be operated normally. Also,
When the engine 3 stops, such as during an idle stop (in the automatic stop of the engine 3), the mechanical hydraulic pump 5 driven by the engine 3 also stops, and the C1 supply pressure is not supplied. Therefore, in order to suppress a transmission shock at the time of restarting the engine (during automatic start of the engine 3), the electric hydraulic pump 11 is driven to supply hydraulic pressure to the C1 clutch 7a. At this time, by operating the first on-off valve 17 to close it, it is possible to prevent the hydraulic oil from leaking to the hydraulic control unit 9 side.

By supplying the hydraulic pressure only to the C1 clutch 7a, which is the minimum required, a small electric hydraulic pump 11 can be used. As described above, in the present embodiment, the hydraulic pressure is maintained even when the engine is stopped, so that the transmission shock due to the restart of the engine can be suppressed.

Next, the operation when the first on-off valve 17 is locked in the closed state will be described. In a state where the first on-off valve 17 is locked, the C1 supply pressure from the hydraulic control unit 9 cannot be supplied via the first on-off valve 17 even if the mechanical hydraulic pump 5 is operated. It is supplied to the C1 clutch 7a through a first check valve 19 arranged in parallel with the first on-off valve 17.

Even if the first on-off valve 17 is locked, if the supply of hydraulic pressure from the hydraulic control unit 9 (or the electric hydraulic pump 11) stops, the minute orifice 21
Through this, the hydraulic pressure in the C1 clutch 7a can be dropped. By these operations, it is possible to prevent the vehicle from being unable to start without supplying the hydraulic pressure to the C1 clutch 7a, to generate creep in the N range due to the hydraulic pressure of the C1 clutch 7a not being appropriately reduced, and to change the speed. The occurrence of lock inside the machine can be prevented.

As described above, the hydraulic control apparatus for the automatic transmission according to the present embodiment includes the fail-safe hydraulic circuit 15 having a configuration corresponding to the first fail-safe mechanism and the second fail-safe mechanism. Various shift operations and the accompanying operations can be suitably performed on the vehicle that controls the automatic stop and start of the vehicle. Therefore, in this embodiment, the original function of the automatic transmission 1 is not impaired.

The hydraulic control unit 9, the second check valve 13, and the fail-safe hydraulic circuit 15 are configured as follows.
This corresponds to the hydraulic control device of the present invention, and the configuration of the first check valve 19 corresponds to the first fail-safe mechanism of the present invention.
The configuration using the small orifice 21 corresponds to the second fail-safe mechanism of the present invention.

(Embodiment 2) Next, Embodiment 2 will be described. The schematic configuration of the hydraulic control device for the automatic transmission according to the second embodiment is the same as that in FIG.
Note that the same configuration will be described with the same number.

A) First, a fail-safe hydraulic circuit, which is a main part of the hydraulic control device, will be described with reference to FIG. FIG. 3A is an explanatory diagram showing a fail-safe hydraulic circuit and the like, and FIG. 3B is an explanatory diagram of a hydraulic switching valve. As shown in FIG. 3A, the fail-safe hydraulic circuit 3
Reference numeral 1 denotes an electromagnetic on-off valve (first on-off valve) 17 for supplying and shutting off the C1 supply pressure from the hydraulic control unit 9, and a first on-off valve 1
When the lock is performed in the closed state, the first bypass valve 17 is bypassed to supply the C1 supply pressure to the C1 clutch 7a.
It includes a check valve 19 and a hydraulic switching valve 35 that operates by sensing the C1 supply pressure from the hydraulic control unit 9 or the supply pressure from the electric hydraulic pump 11.

Here, the first opening / closing valve 17 is a normally open valve that connects a hydraulic path by a spring when power is not supplied and shuts off the hydraulic path when power is supplied. The first check valve 19 is connected in parallel with the first on-off valve 17, and is a check valve that permits only the supply of the C1 supply pressure from the hydraulic control unit 9 to the C1 clutch 7a.

In order to apply the hydraulic pressure from the hydraulic control unit 9 to the hydraulic switching valve 35, the fail-safe hydraulic circuit 31 receives the hydraulic switching valve 35 from the hydraulic control unit 9.
The hydraulic path 34a is provided between the electric hydraulic pump 11 and the second check valve 13 so as to supply hydraulic pressure from the electric hydraulic pump 11 to the hydraulic switching valve 35. A hydraulic path 34b reaching the valve 35 is provided.

The hydraulic switching valve 35 has a spool valve structure as shown in FIG. 3 (b), and is pressed to the right in FIG. Are both open. Therefore, when the hydraulic switching valve 35 senses the C1 supply pressure from the hydraulic control unit 9 or the supply pressure from the electric hydraulic pump 11, the hydraulic switching valve 35 cuts off the hydraulic path from the C1 clutch 7a to the drain. When the supply pressure is not sensed, it operates to open the hydraulic path from the C1 clutch 7a to the drain.

In this embodiment, the second check valve 13 is also shown as a configuration of the fail-safe hydraulic circuit 31. c)
Next, the operation of the hydraulic control device of the present embodiment will be described. First, the normal operation of the hydraulic control device will be described.

As shown in FIG. 3B, when the C1 supply pressure acts on the hydraulic pressure switching valve 35 from the hydraulic pressure control unit 9 in the normal state, the area of the pressure receiving surface 43 provided on the valve body 47 is reduced.
5 is larger than the area of the valve body 4,
7 moves to the left in the figure. When the valve element 47 moves to the left, the communication port 39 communicating with the C1 clutch 7a and the communication port 41 communicating with the drain are closed, so that the hydraulic pressure in the C1 clutch 7a does not leak.

When the C1 supply pressure is no longer supplied from the hydraulic control unit 9 to the hydraulic switching valve 35, the hydraulic pressure acting on the pressure receiving surface 43 and the pressure receiving surface 45 is lost, and the valve body 47 is moved by the spring force of the spring 37. To the right to open the communication port 39 and the communication port 41.

When the oil pressure is supplied from the oil pressure control unit 9 by the operation of the oil pressure switching valve 35, the leakage from the C1 clutch 7a is extremely reduced. On the other hand, at the time of the idle stop, the supply of the hydraulic pressure by the mechanical hydraulic pump 5 stops with the stop of the engine. At this time, the first
Since the on-off valve 17 is driven and its hydraulic path is closed, it is possible to prevent the hydraulic pressure in the C1 clutch 7a from leaking to the hydraulic control unit 9 side.

At this time, the hydraulic pressure on the hydraulic control unit 9 side decreases. However, since the electric hydraulic pump 11 is driven to supply the hydraulic pressure, the supply pressure from the electric hydraulic pump 11 flows through the hydraulic path 34b. Acts on the pressure receiving surface 49 through the valve body 47 to maintain the state in which the valve body 47 is pressed to the left.

Accordingly, since the valve element 47 is pressed to the left, the communication port 39 communicating with the C1 clutch 7a is provided.
The communication port 41 communicating with the C1 clutch 7a is kept closed, so that the hydraulic pressure in the C1 clutch 7a does not leak. By the above two actions, the C1 clutch 7a becomes a closed space and the leakage of hydraulic pressure is very small, so that a small electric hydraulic pump 11 can be used.
In addition, since the hydraulic pressure of the C1 clutch 7a is secured, the transmission shock accompanying the restart of the engine does not occur.

After that, when the engine restart is completed, the first
When the on-off valve 17 is not driven and its hydraulic path is opened, the oil path connecting the C1 clutch 7a and the hydraulic control unit 9 is opened. At this time, while the C1 supply pressure is supplied and the hydraulic pressure of the C1 clutch 7a is maintained, the valve body 47
Is also left-moving, so that the vehicle can be started.

Next, the operation when the first on-off valve 17 is locked in the closed state will be described. First on-off valve 17
Is locked in the closed state, the C1 supply pressure from the hydraulic control unit 9 bypasses the first opening / closing valve 17 and is supplied to the C1 clutch 7a through the first check valve 19.

When the supply of the hydraulic pressure from the hydraulic control unit 9 is stopped, the hydraulic pressure acting on the pressure receiving surfaces 43 and 45 disappears, and the force for pressing the valve body 47 to the left disappears. Moves to the right by the spring force of
The communication ports 39 and 41 are opened. Similarly, when the supply of hydraulic pressure from the electric hydraulic pump 11 stops, there is no longer any force to press the valve body 47 to the left, and the valve body 47 moves to the right by the spring force of the spring 37, and the communication ports 39, 41 To release.

That is, even if the first on-off valve 17 is locked,
Since the hydraulic pressure in the C1 clutch 7a can be dropped through the hydraulic pressure switching valve 35, the original function of the automatic transmission 1 is not impaired. That is, it is possible to prevent the vehicle from being unable to start without the hydraulic pressure of the C1 clutch 7a being supplied, to prevent creep in the N range due to the hydraulic pressure of the C1 clutch 7a not being appropriately reduced, Locking can be prevented.

As described above, in the hydraulic control apparatus for the automatic transmission according to the present embodiment, the same effect as that of the first embodiment is obtained, and particularly, since the hydraulic pressure is controlled by the hydraulic switching valve 35, a minute orifice is used. There is an advantage that unnecessary hydraulic pressure can be reduced as compared with the case.

The structure of the first check valve 19 corresponds to the first fail-safe mechanism of the present invention, and the hydraulic switching valve 35
Corresponds to the second fail-safe mechanism of the present invention. Third Embodiment Next, a third embodiment will be described.

The schematic structure of the hydraulic control device for an automatic transmission according to the third embodiment is the same as that shown in FIG. 1, and a description thereof will be omitted. Note that the same configuration will be described with the same number. a) First, a fail-safe hydraulic circuit, which is a main part of the hydraulic control device, will be described with reference to FIG. FIG. 4 is an explanatory diagram showing a fail-safe hydraulic circuit and the like.

As shown in FIG. 4, the fail-safe hydraulic circuit 51 supplies the C1 supply pressure from the hydraulic control unit 9
An electromagnetic on-off valve (first on-off valve) 53 that shuts off and an electromagnetic on-off valve (second on-off valve) 55 that is connected in parallel with the first on-off valve 53 and opens and closes a hydraulic path thereof are provided.

Here, the first on-off valve 53 is a normally open valve that normally opens the hydraulic path by the urging force of the spring and closes the hydraulic path when energized, while the second on-off valve 55 is normally open. This is a normally closed valve that closes the hydraulic path by the biasing force of a spring and opens the hydraulic path when power is supplied.

C) Next, the operation of the hydraulic control device of this embodiment will be described. First, the normal operation of the hydraulic control device will be described. When the C1 supply pressure is supplied from the hydraulic control unit 9 by the operation of the mechanical hydraulic pump 5, the first on-off valve 53 is normally open and the second on-off valve 55 is normally closed. The C1 supply pressure is directly supplied to the C1 clutch 7a via the valve 53.

Further, when the engine 3 stops, as in the idle stop, the mechanical hydraulic pump 5 driven by the engine 3 also stops, and the C1 supply pressure is not supplied.
Therefore, in order to suppress the transmission shock when the engine is restarted, the electric hydraulic pump 11 is driven to drive the C1 clutch 7a.
Supply hydraulic pressure to

At this time, by operating the first on-off valve 53 to close it, it is possible to prevent the hydraulic oil from leaking to the hydraulic control unit 9 side. Next, an operation when the first on-off valve 53 is locked in a closed state will be described.

In a state where the first on-off valve 53 is locked, the C1 supply pressure from the hydraulic control unit 9 cannot be supplied via the first on-off valve 53.
3 is locked (for example, with a sensor or switch)
When it is detected, the second on-off valve 55 is energized to open the second on-off valve 55.

As a result, the first on-off valve 53 is bypassed and the second
The C1 supply pressure can be supplied to the C1 clutch 7a via the on-off valve 55. When the hydraulic pressure of the C1 clutch 7a needs to be released, the hydraulic pressure of the C1 clutch 7a can be released to the hydraulic control unit 9 by energizing and opening the second on-off valve 55.

With these operations, in this embodiment, the original functions of the automatic transmission 1 are not impaired. That is, C
It is possible to prevent the vehicle from being unable to start without the hydraulic pressure of the one clutch 7a being supplied, to generate creep in the N range due to the hydraulic pressure of the C1 clutch 7a not being appropriately reduced, and to lock the inside of the transmission. Occurrence can be prevented.

Incidentally, the configuration of the second on-off valve 55 corresponds to the first and second fail-safe mechanisms of the present invention. Further, as a configuration different from the third embodiment, instead of the normally open first on-off valve 53 and the normally closed second on-off valve 55 of the present embodiment, both of them are normally open electromagnetic on-off valves. The configuration of the on-off valve and the second on-off valve can be adopted.

In this case, the same effect as that of the third embodiment, such as hydraulic control, is obtained, and the sensor for detecting the lock of the first on-off valve by simultaneously driving the first on-off valve and the second on-off valve. There is an advantage that an appropriate opening / closing operation of the second opening / closing valve can be performed without providing such an arrangement.

For example, in order to open the hydraulic path from the hydraulic control unit 9 to the C1 clutch 7a, when both open / close valves are operated from closed to open, the both open / close valves may be de-energized. For example, even if the first on-off valve is locked, the hydraulic path can be opened by the second on-off valve. The second
When the on-off valve is locked, the opening and closing of the hydraulic path can be controlled by the first on-off valve.

(Fourth Embodiment) Next, a fourth embodiment will be described. The schematic configuration of the hydraulic control device for an automatic transmission according to the fourth embodiment is the same as that in FIG.
Note that the same configuration will be described with the same number.

A) First, a fail-safe hydraulic circuit, which is a main part of the hydraulic control device, will be described with reference to FIG. FIG. 5 is an explanatory diagram showing a fail-safe hydraulic circuit and the like. As shown in FIG. 5, the fail-safe hydraulic circuit 61
A solenoid on-off valve (first on-off valve) 63 for supplying and shutting off the C1 supply pressure from the hydraulic control unit 9;
And a first check valve 65 that bypasses the first opening / closing valve 63 and supplies the C1 supply pressure to the C1 clutch 7a when locked in a closed state.

The first opening / closing valve 33 is a normally open valve that opens a hydraulic path by a spring when power is not supplied, and substantially shuts off the hydraulic path when power is supplied. The small orifice 63a is formed so that a small amount of hydraulic oil can leak without completely shutting off the oil.

The first check valve 65 is provided with a first on-off valve 63.
The check valve is connected in parallel with the first control valve and permits only the supply of the C1 supply pressure from the hydraulic control unit 9 to the C1 clutch 7a. c) Next, the operation of the hydraulic control device of the present embodiment will be described. First, the normal operation of the hydraulic control device will be described.

When the C1 supply pressure is supplied from the hydraulic control unit 9 by the operation of the mechanical hydraulic pump 5, the first open / close valve 63 is normally open.
, The C1 supply pressure is supplied to the C1 clutch 7a as it is. Also, as in idle stop, the engine 3
Stops, the mechanical hydraulic pump 5 also stops, and the C1 supply pressure is no longer supplied. Therefore, in order to suppress the transmission shock when the engine is restarted, the electric hydraulic pump 11 is driven to supply the hydraulic pressure to the C1 clutch 7a.

At this time, by operating the first on-off valve 63 to close it, it is possible to prevent the hydraulic oil from leaking to the hydraulic control unit 9 side. Next, an operation when the first on-off valve 63 is locked in a closed state will be described.

In a state where the first on-off valve 63 is locked, the C1 supply pressure from the hydraulic control unit 9 cannot be supplied via the first on-off valve 63.
3, the C1 supply pressure can be supplied to the C1 clutch 7a via the first check valve 65.

Even if the first on-off valve 63 is locked, if the supply of hydraulic pressure from the hydraulic control unit 9 (or the electric hydraulic pump 11) stops, the minute orifice 63
The hydraulic pressure in the C1 clutch 7a can be dropped through a. By these operations, in the present embodiment, the original function of the automatic transmission 1 is not impaired. That is,
It is possible to prevent the vehicle from being unable to start due to the hydraulic pressure of the C1 clutch 7a not being supplied, to generate creep in the N range due to the hydraulic pressure of the C1 clutch 7a not being appropriately reduced, and to lock the inside of the transmission. Occurrence can be prevented.

The configuration using the first check valve 65 corresponds to a first fail-safe mechanism according to the present invention, and the configuration using the small orifice 63a corresponds to a second fail-safe mechanism according to the present invention. It is needless to say that the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a schematic configuration of a hydraulic control device for an automatic transmission according to a first embodiment.

FIG. 2 is an explanatory diagram showing a configuration of a fail-safe hydraulic circuit according to the first embodiment and peripheral components thereof;

FIG. 3A is an explanatory view showing a fail-safe hydraulic circuit according to a second embodiment and a configuration around the fail-safe hydraulic circuit, and FIG. 3B is an explanatory view showing a hydraulic switching valve.

FIG. 4 is an explanatory diagram showing a configuration of a fail-safe hydraulic circuit according to a third embodiment and a configuration around the fail-safe hydraulic circuit;

FIG. 5 is an explanatory diagram showing a fail-safe hydraulic circuit according to a fourth embodiment and a configuration around the fail-safe hydraulic circuit;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Automatic transmission 3 ... Engine 5 ... Mechanical hydraulic pump 7a ... C1 clutch 9 ... Hydraulic control unit 11 ... Electric hydraulic pump 13 ... Second check valve 15, 31, 51, 61 ... Fail safe hydraulic circuit 17, 63: first on-off valve 19, 65 ... first check valve 21, 63a ... minute orifice 35 ... hydraulic switching valve 55 ... second on-off valve

Continuation of the front page (72) Inventor Akira Kato 1-1-1, Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (reference) 3J552 MA02 MA11 NA01 NB01 PA02 PA06 PA26 PA46 PA67 PB06 QA06A QA28A QA30C QA36A QA42A QB01 QB08 RC01 RC02 SA07 VA52W VA79W VC01W VC02W

Claims (14)

[Claims] A first opening / closing valve disposed in a hydraulic path between a friction engagement element of the automatic transmission and a first hydraulic pressure generating means for opening and closing the hydraulic path; By the first hydraulic pressure generating means,
Hydraulic pressure is supplied to the friction engagement element through the first on-off valve, and when the engine is stopped, the first on-off valve is closed, and hydraulic pressure is applied to the friction engagement element by a second hydraulic pressure generating means. A fluid pressure control device for an automatic transmission for supplying, wherein when the first on-off valve is fixed in a closed state and the engine is driven, the first fluid pressure generation means causes the frictional engagement element to be driven. A fluid pressure control device for an automatic transmission, comprising: a first fail-safe mechanism capable of supplying a fluid pressure. A first opening / closing valve disposed in a hydraulic path between the friction engagement element of the automatic transmission and the first hydraulic pressure generating means for opening and closing the hydraulic path; The first hydraulic pressure generating means
Hydraulic pressure is supplied to the friction engagement element of the automatic transmission via the on-off valve, and when the engine is stopped, the first on-off valve is closed, and hydraulic pressure is applied to the friction engagement element by the second hydraulic pressure generation means. A fluid pressure control device for an automatic transmission, comprising: a second fail-safe mechanism that can release fluid pressure from the frictional engagement element when the first on-off valve is fixed in a closed state. A hydraulic pressure control device for an automatic transmission, characterized by: A first opening / closing valve disposed in a hydraulic path between the friction engagement element of the automatic transmission and the first hydraulic pressure generating means for opening and closing the hydraulic path; The first hydraulic pressure generating means
Hydraulic pressure is supplied to the friction engagement element of the automatic transmission via the on-off valve, and when the engine is stopped, the first on-off valve is closed, and hydraulic pressure is applied to the friction engagement element by the second hydraulic pressure generation means. A hydraulic pressure control device for an automatic transmission for supplying, comprising: a first fail-safe mechanism according to claim 1, and a second fail-safe mechanism according to claim 2. Machine hydraulic pressure control device. 4. The first fail-safe mechanism, wherein the first fail-safe mechanism is disposed in parallel with the first on-off valve in a fluid pressure path between the first fluid pressure generating means and the frictional engagement element, and 4. A first check valve according to claim 1, further comprising a first check valve for permitting the supply of the hydraulic pressure from the pressure generating means side to the friction fastening element side and prohibiting the supply in the opposite direction. Hydraulic pressure control device for automatic transmission. 5. A small orifice interposed between the frictional engagement element and the drain as the second fail-safe mechanism.
3. The hydraulic pressure control device for an automatic transmission according to claim 1. 6. The friction-fastening element, wherein the second fail-safe mechanism is interposed in a hydraulic path between the first hydraulic-pressure generating means and the friction-engaging element in parallel with the first on-off valve. 4. The hydraulic pressure control device for an automatic transmission according to claim 2, further comprising a hydraulic pressure switching valve capable of switching between a state in which the hydraulic pressure is released from the state and a state in which the hydraulic pressure is not released. 7. The hydraulic pressure switching valve according to claim 1, wherein the hydraulic pressure switching valve opens and closes by sensing a hydraulic pressure from the first hydraulic pressure control means side or a hydraulic pressure from the second hydraulic pressure generation means side. Item 7. A hydraulic pressure control device for an automatic transmission according to Item 6. 8. The first fail-safe mechanism and / or the second fail-safe mechanism may include: The hydraulic pressure control device for an automatic transmission according to any one of claims 1 to 3, further comprising a second on-off valve interposed and capable of opening and closing the hydraulic pressure path. 9. The downstream side of the first on-off valve, wherein the second
A second hydraulic pressure generating means interposed between the hydraulic pressure generating means and the frictional fastening element for permitting supply of hydraulic pressure from the second hydraulic pressure generating means side to the frictional fastening element side and prohibiting supply in the reverse direction; The hydraulic pressure control device for an automatic transmission according to any one of claims 1 to 8, further comprising a two check valve. 10. A hydraulic pressure control unit, which is provided between the first hydraulic pressure generating means and the frictional engagement element and adjusts a state of supply of hydraulic pressure to the frictional engagement element. The hydraulic pressure control device for an automatic transmission according to claim 1. 11. At least one of the first on-off valve, the first check valve, the hydraulic pressure switching valve, and the second on-off valve between the hydraulic control unit and the friction engagement element. The hydraulic pressure control device for an automatic transmission according to claim 10, further comprising: 12. The hydraulic pressure control device for an automatic transmission according to claim 1, wherein the hydraulic pressure control device is mounted on a vehicle that controls automatic stop and automatic start of the engine. 13. The valve according to claim 1, wherein the first on-off valve and / or the second on-off valve is an electromagnetic on-off valve.
The hydraulic pressure control device for an automatic transmission according to any one of claims 12 to 12. 14. The hydraulic pressure control device for an automatic transmission according to claim 1, wherein the automatic transmission is a planetary gear type automatic transmission.