JP2009133362A - Hydraulic control device of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately take advantage of a cooler by-pass pipe without being influenced by a capacity of an oil pump, while detecting damages of an oil cooler and an input check valve. <P>SOLUTION: A cooler by-pass valve 5 absorbs each hydraulic pressure at the both ends of a cooler piping passage 3 and detects the pressure differential between an input port 1c of an input check valve 1 and an input port 4c of an output check valve 4 and when both inputs are small and when both the inputs become bigger, the input port 5c of the cooler by-pass valve 5 remains closed. However, if a difference in hydraulic pressure occurs between the both ends of the cooler piping passage 3 and the input port 5c of the cooler by-pass valve 5 has an increasing difference in hydraulic pressure when the piston 5a is depressed against an elastic force of the spring 5b and a hydraulic pressure of the other input port 5e, the input port 5c and the output port 5d are communicated, so that the operating oil passing through the cooler by-pass piping passage 6 is outputted to a predetermined region. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to an abnormality process for a cooling pipe of an oil passage that supplies hydraulic pressure to the automatic transmission.

As a conventional hydraulic control device for an automatic transmission, the technique of Patent Document 1 shown in FIG. 3 is known. FIG. 3 is a piping diagram for explaining the relationship between an oil cooler of a conventional hydraulic control device for an automatic transmission and its bypass system.
In particular, the relationship between the oil cooler and its bypass system in Patent Document 1 will be described as follows.
When the hydraulic oil is sent by an oil pump (not shown) as an oil cooler input for cooling the hydraulic oil contained in the automatic transmission, the hydraulic oil disposed in the cooler piping 20 is specified when the hydraulic pressure exceeds a predetermined level. After the input check valve 21 flowing in the direction is pressed and cooled by the oil cooler 22, it is output as an oil cooler output to be supplied to each lubricating element as lubricating oil.
Normally, when hydraulic oil of a predetermined pressure or higher is sent as an oil cooler input in this state, the input check valve 21 is opened, the hydraulic oil passes through the cooler pipe line 20, and is cooled by the oil cooler 22. After that, it is output as lubricating oil and used as lubricating oil.

Here, when the hydraulic oil pressure further rises to a predetermined pressure or higher, the oil cooler bypass valve 23 moves the valve against the urging force in the valve closing direction. The valve is opened, a cooler bypass piping 24 is formed, and hydraulic oil is output through the cooler bypass piping 24 without passing through the oil cooler 22.
As described above, the oil cooler bypass valve 23 opens when the oil pressure of the cooler pipe line 20 in the oil cooler 22 becomes equal to or higher than a predetermined pressure, and the oil cooler 22 is damaged due to the rise of the cooler pipe line 20. It serves as a protective conduit to avoid. The pressure at which the oil cooler bypass valve 23 is opened can be adjusted by setting a built-in spring.
JP2007-2111968

However, since the technique of Patent Document 1 has a protective function for avoiding damage to the oil cooler 22 due to the rise of the cooler piping 20, the pressure at which the oil cooler bypass valve 23 is opened is normally The drag in the valve closing direction of the built-in spring is set to a high value so as not to hinder the operation. Therefore, even if the oil cooler 22 is damaged, there is a possibility that the oil cooler bypass valve 23 does not operate because the elastic force of the spring built in the oil cooler bypass valve 23 is set high. In particular, when the capacity of the oil pump decreases, the probability that the oil cooler 22 will not operate even if it is damaged increases.
Further, when the engine is started, the viscosity of the hydraulic oil is lowered in a cold region, so that the oil passage resistance (fluid resistance) of the oil cooler is lowered and the supply to the lubrication member in the oil cooler downstream circuit is insufficient. there is a possibility.

  Accordingly, the present invention has been made to solve such a problem. Even when the hydraulic oil is at a low temperature, the supply to the lubricating member is sufficiently performed, and the oil cooler and the input are not affected by the ability of the oil pump. An object of the present invention is to provide a hydraulic control device for an automatic transmission that can detect damage to a check valve and accurately utilize a cooler bypass pipe.

The hydraulic control device for an automatic transmission according to claim 1 outputs hydraulic oil contained in the automatic transmission to an oil cooler via an input check valve that operates at a specific hydraulic pressure, and also outputs a predetermined portion from the oil cooler. When the pressure difference between the upstream side and the downstream side of the oil cooler exceeds a predetermined threshold value in the hydraulic control device for the automatic transmission that outputs the hydraulic oil to the upstream side of the oil cooler by the cooler bypass piping. The hydraulic oil is output to the predetermined portion without passing through the oil cooler.
Here, the cooler bypass pipe takes in the oil pressure at both ends of the oil cooler, and when the oil pressure on the upstream side of the oil cooler is larger than a predetermined threshold value, the upstream side of the oil cooler via the cooler bypass pipe line Is output to the predetermined part.

In the cooler bypass piping of the hydraulic control device for an automatic transmission according to claim 2, the input check valve is disposed on the upstream side of the oil cooler, and the upstream side of the input check valve and the downstream of the oil cooler. A cooler bypass valve that outputs the hydraulic pressure upstream of the input check valve to the predetermined portion when the pressure difference on the side is larger than a predetermined threshold value.
Here, the cooler bypass valve takes in the oil pressure at both ends of the oil cooler, and when the oil pressure on the upstream side of the oil cooler is larger than a predetermined threshold value, the upstream side of the oil cooler via the cooler bypass pipe line Is used as an output to the predetermined part. The output check valve only needs to have a function as a check valve.

In the cooler bypass piping of the hydraulic control device for an automatic transmission according to claim 3, the input check valve is disposed on the upstream side of the oil cooler, and the upstream side of the input check valve and the downstream of the oil cooler. When the pressure difference between the upstream side of the input check valve and the downstream side of the oil cooler is greater than a predetermined threshold value, the input check valve A switching valve for switching to output the hydraulic pressure on the upstream side to the predetermined portion.
Here, the switching valve takes in the oil pressure at both ends of the oil cooler, and when the oil pressure on the upstream side of the oil cooler is larger than a predetermined threshold value, the upstream side of the oil cooler is connected via a cooler bypass pipe line. Switching is performed so that the hydraulic pressure is output to the predetermined portion. That is, the switching valve may be any valve that detects the hydraulic pressure of the hydraulic oil and opens and closes the valve.

  The cooler bypass piping that is output to the predetermined part of the hydraulic control device for an automatic transmission according to claim 4 has an inflow from the cooler bypass piping to the oil cooler between the downstream side of the oil cooler. An output check valve for blocking is provided. The output check valve is for making the outputs of the oil cooler and the cooler bypass valve as a single output, but any output check valve may be used as long as it has a function as a check valve.

The hydraulic control device for an automatic transmission according to claim 1 outputs hydraulic oil contained in the automatic transmission to an oil cooler via an input check valve that operates at a specific hydraulic pressure, and also outputs a predetermined portion from the oil cooler. In the hydraulic control device for the automatic transmission that outputs hydraulic oil to the oil pressure, when the pressure difference between the upstream side and the downstream side of the oil cooler is larger than a predetermined threshold value, the hydraulic pressure on the upstream side of the oil cooler is reduced by a cooler bypass piping. Output directly to the predetermined part.
Therefore, when the temperature of the hydraulic oil at the oil cooler input that is output from the oil pump rises and the oil flow resistance (fluid resistance) decreases, the fluidity of the hydraulic oil increases, and a hydraulic pressure exceeding a predetermined threshold is applied to the input check valve The hydraulic oil can be cooled by the oil cooler. However, when the input check valve malfunctions, the oil cooler is clogged with foreign matter, or the pipeline is damaged, the oil pressure on the upstream side of the oil cooler increases and the pressure difference from the oil pressure on the downstream side is large. Become. When this is detected by the cooler bypass valve, the hydraulic oil that is input to the oil cooler is output through the cooler bypass pipe line without being cooled. Therefore, even if the capacity of the oil pump is reduced, the pressure difference between the upstream side and the downstream side of the oil cooler is detected at the same time, so that the influence can be removed. Even if the operating pressure of the input check valve is close to the threshold value of the pressure difference between the two sides of the oil cooler, the pressure difference between the two sides of the oil cooler cancels out the capability of the oil pump. High operation can be expected.

  The cooler bypass piping of the hydraulic control device for an automatic transmission according to claim 2 is provided with a cooler bypass valve, the input check valve is disposed upstream of the oil cooler, and upstream of the input check valve. In addition to the effect according to claim 1, the hydraulic pressure on the upstream side of the input check valve is output to the predetermined part when the pressure difference between the side of the oil cooler and the downstream side of the oil cooler is greater than a predetermined threshold value. Thus, the number of valves can be reduced and the overall configuration can be simplified.

The cooler bypass piping of the hydraulic control device for an automatic transmission according to claim 3 includes a switching valve, the input check valve is disposed upstream of the oil cooler, and the upstream side of the input check valve. When the pressure difference between the oil cooler and the downstream side of the oil cooler is greater than or equal to a predetermined threshold value, the hydraulic pressure on the upstream side of the input check valve is switched to be output to the predetermined portion. In addition, when an abnormality occurs in the cooler pipe line, it is possible to smoothly switch to the cooler bypass pipe line and stably supply hydraulic oil to the predetermined part as an oil cooler output.
In particular, since the pressure difference between the two sides of the oil cooler cancels out the capacity of the oil pump, a highly reliable operation can be expected. When an abnormality occurs in the oil cooler, the oil cooler can be smoothly switched to the cooler bypass piping, and output to the predetermined portion.

  An inflow from the cooler bypass piping to the oil cooler is provided between the cooler bypass piping to be output to the predetermined portion of the hydraulic control device for the automatic transmission according to claim 4 and a downstream side of the oil cooler. Therefore, in addition to the effect described in any one of claims 1 to 3, inflow from the cooler bypass piping to the oil cooler can be prevented. Since the pressure on the downstream side of the oil cooler does not fluctuate, the amount of oil in the cooler bypass piping can be stably supplied to the predetermined portion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the drawings, in the embodiment, the same symbols and the same reference numerals are the same or corresponding functional parts, and therefore, redundant description is omitted here.
[Embodiment 1]

FIG. 1 is a piping diagram showing a connection relationship of a hydraulic control device for an automatic transmission according to a first embodiment of the present invention.
In FIG. 1, an oil cooler input is a hydraulic pressure sent out by applying pressure to hydraulic oil by an oil pump driven by rotation of a turbine runner (not shown). The input check valve 1 functioning as a torque converter check valve comprising a check valve presses the piston 1a against the elastic force of the spring 1b when the oil pressure of the oil cooler input exceeds a predetermined value, and the input port The valve 1c communicates with the output port 1d.

  The hydraulic oil that has passed through the output port 1 d of the input check valve 1 is cooled by the oil cooler 2. In addition, the cooler piping 3 of this Embodiment is comprised from the input port 1c of the input check valve 1 to the output of the oil cooler 2 (up to the input port 4c of the output check valve 4).

  The downstream side of the cooler piping 3 is connected to an input port 4c of an output check valve 4 that functions as a torque converter check valve including a check valve. The output check valve 4 determines the direction in which the hydraulic oil cooled by the oil cooler 2 flows. When the piston 4a is pressed against the elastic force of the spring 4b, the input port 4c and the output port 4d communicate with each other. To do. That is, in the output check valve 4, the hydraulic oil cooled by the oil cooler 2 passes through the input port 4c and the output port 4d and becomes an oil cooler output. The output check valve 4 acts as a check valve and is opened when the input port 4c is equal to or higher than a predetermined low hydraulic pressure.

  The oil cooler input hydraulic pressure is input to one input port 5 c of the cooler bypass valve 5. The cooler bypass valve 5 has two input ports 5c, an input port 5e, and an output port 5d as an output of the input port 5c. The piston 5a responds to the hydraulic pressure of the two input ports 5c and the input port 5e. The hydraulic pressure of the input port 5e and the elastic force of the spring 5b are applied to one side, and the hydraulic pressure of the input port 5c is applied to the other side. The oil pressure after passing through the oil cooler 2 is introduced into the input port 5 e from the input port 4 c on the output check valve 4 side of the cooler piping 3.

Accordingly, the cooler bypass valve 5 allows the sum of the hydraulic pressure of the input port 5e and the elastic force of the spring 5b, that is, the sum of the hydraulic pressure of the cooling hydraulic oil output from the oil cooler 2 and the elastic force set in the spring 5b and the input port 5c. The difference between the hydraulic pressure, that is, the oil cooler input hydraulic pressure is detected.
Here, the pipeline from the oil cooler input to the oil cooler output (output port 4d of the output check valve 4) through the input port 5c and the output port 5d constitutes the cooler bypass piping 6 of the present embodiment. ing.

  Therefore, the hydraulic pressure of the input port 5c of the cooler bypass valve 5 presses the piston 5a against the elastic force of the spring 5b and the hydraulic pressure of the other input port 5e when the oil pressure of the oil cooler input exceeds a predetermined value. The input port 5c and the output port 5d communicate with each other. At this time, the output of the output check valve 4 is higher than that of the cooling hydraulic oil output from the oil cooler 2, so that the output check valve 4 blocks the flow of the oil cooler. Without passing 2, the oil cooler output is passed through the cooler bypass piping 6.

  The hydraulic control device for an automatic transmission according to the present embodiment outputs hydraulic oil contained in the automatic transmission to an oil cooler 2 via an input check valve 1 that operates at a specific hydraulic pressure, and from the oil cooler 2. In a hydraulic control device for an automatic transmission that outputs hydraulic oil to a predetermined portion, when the pressure difference between the upstream side and the downstream side of the oil cooler 2 is larger than a predetermined threshold value, the hydraulic pressure on the upstream side of the oil cooler 2 is changed to the oil cooler 2. The cooler bypass piping 6 that directly outputs to a predetermined part without using the air is provided.

  Specifically, it has an input check valve 1 that operates at a specific hydraulic pressure and flows hydraulic oil stored in the automatic transmission in a specific direction, a cooler piping 3 that cools the hydraulic oil by an oil cooler 2, and a cooler. The oil pressure at both ends of the pipe line 3 is taken in, and the pressure difference between the upstream side of the cooler pipe line 3, that is, the input port 1 c of the input check valve 1, and the downstream side, that is, the input port 4 c of the output check valve 4. When the pressure difference between the upstream side and the downstream side of the cooler pipe line 3 is detected and larger than a predetermined threshold, the cooler bypass valve that outputs the hydraulic pressure on the upstream side of the cooler pipe line 3 through the cooler bypass pipe line 6 5, between the downstream side of the cooler pipe line 3 and the output of the cooler bypass valve 5, and the cooler bypass from the downstream side of the cooler pipe line 3 In only one direction of the output side of the lube 5 is to comprise an output check valve 4 to flow the hydraulic oil.

The hydraulic control device for the automatic transmission according to the first embodiment configured as described above operates as follows.
First, at the initial driving of the engine, the input check valve 1 is opened by a predetermined pressure of hydraulic oil as an oil cooler input output from an oil pump driven by the rotation of the turbine runner. Of course, the cooler bypass valve 5 detects the pressure difference between the input port 1c of the input check valve 1 and the input port 4c of the output check valve 4 by taking in the hydraulic pressure at both ends of the cooler piping 3 respectively. When the input is small, the input port 5c of the cooler bypass valve 5 remains closed.

  When the temperature of the hydraulic oil as an oil cooler input output from the oil pump increases due to the driving of the engine, the oil flow resistance decreases and the viscosity of the hydraulic oil decreases. Then, the fluidity of the hydraulic oil is increased, and a hydraulic pressure of a predetermined value or more is applied to the input check valve 1. When a hydraulic pressure higher than a predetermined value is applied to the input check valve 1, the hydraulic oil stored in the automatic transmission passes through the cooler piping 3 and is heat-exchanged and cooled by the oil cooler 2. The cooled hydraulic oil passes from the input port 4c of the output check valve 4 to the output port 4d, becomes an oil cooler output, and is supplied for lubrication of the clutch and brake of the transmission mechanism.

  However, when the temperature is low, the viscosity of the hydraulic oil is decreased, the oil passage resistance (fluid resistance) is decreased, or the fluid resistance that causes the hydraulic oil to flow through the cooler piping 3 is increased, for example, the failure of the oil cooler 2, the input check When the failure of the valve 1 or the damage of the cooler pipe line 3 such as clogging occurs, a difference occurs in the oil pressure at both ends of the cooler pipe line 3. Specifically, the oil pressure of the input port 1c of the input check valve 1 is It becomes higher than the hydraulic pressure of the input port 4 c of the output check valve 4. If a pressure difference equal to or greater than a predetermined threshold value occurs in the oil pressure of the input port 5c of the cooler bypass valve 5 between the elastic force of the spring 5b of the piston 5a and the oil pressure pressed against the oil pressure of the other input port 5e. And the output port 5d communicate with each other. Therefore, the hydraulic oil that passes through the cooler bypass piping 6 without passing through the oil cooler 2 is output for lubrication of clutches, brakes, and the like of the transmission mechanism.

As described above, the cooler bypass valve 5 detects the pressure difference between the input port 1 c of the input check valve 1 and the input port 4 c of the output check valve 4 by taking in the hydraulic pressure at both ends of the cooler piping 3. Therefore, even when both inputs are small and when both inputs are large, both pressure differences do not occur, so the input port 5c of the cooler bypass valve 5 remains closed. However, there is a difference in the hydraulic pressure at both ends of the cooler piping 3, and there is a hydraulic pressure difference that presses the piston 5 a against the elastic force of the spring 5 b and the hydraulic pressure of the other input port 5 e on the input port 5 c of the cooler bypass valve 5. When this occurs, the input port 5c and the output port 5d communicate with each other, and the hydraulic oil that passes through the cooler bypass piping 6 is output without passing through the cooler piping 3 side. Accordingly, the hydraulic oil is supplied for lubrication of the clutch and brake of the transmission mechanism without being cooled.
[Embodiment 2]

FIG. 2 is a piping diagram showing the connection relationship of the hydraulic control device for an automatic transmission according to the second embodiment of the present invention.
In the first embodiment, a check valve is used as the output check valve 4, but this can be replaced with a switching valve. Here, only differences from the first embodiment will be described.

  The cooler bypass valve 7 has an input port 7f and an input port 7g as passages for two hydraulic oils, and an output port 7d as a common output thereof. Moreover, it has the pressure receiving port 7c and the pressure receiving port 7e which detect the hydraulic pressure of two hydraulic fluids. The piston 7a that switches between the two input ports 7f and the input port 7g is configured such that the hydraulic pressure of the pressure receiving port 7e and the elastic force of the spring 7b are applied to one, and the hydraulic pressure of the pressure receiving port 7c is applied to the other. ing. That is, the switching valve used as the cooler bypass valve 7 detects the hydraulic pressure of the hydraulic oil and opens and closes the valve. In detail, the hydraulic pressure at both ends of the oil cooler 2 is taken in, and the upstream side of the oil cooler 2 is taken in. When the hydraulic pressure is larger than a predetermined threshold value, the hydraulic pressure on the upstream side of the oil cooler 2 is switched via the cooler bypass piping 6 to output to a predetermined portion for lubrication of the clutch, brake, etc. of the transmission mechanism. Is.

An oil cooler input is introduced into the pressure receiving port 7c, and the oil pressure after passing through the oil cooler 2 is introduced into the pressure receiving port 7e. Therefore, the cooler bypass valve 7 has the sum of the hydraulic pressure of the pressure receiving port 7e and the elastic force of the spring 7b, that is, the sum of the hydraulic pressure of the cooling hydraulic oil output from the oil cooler 2 and the elastic force set in the spring 7b, and the pressure receiving port 7c. The difference between the oil pressure and the oil cooler input oil pressure is detected.
Here, from the oil cooler input to the oil cooler output through the input port 7f and the output port 7d, the cooler bypass piping 6 is constructed, and from the input port 1c of the input check valve 1 to the output of the oil cooler 2 (cooler bypass) The cooler piping 3 is constituted by the valve 7).

  The hydraulic control device for the automatic transmission according to the second embodiment outputs the hydraulic oil contained in the automatic transmission to the oil cooler 2 through the input check valve 1 that operates at a specific hydraulic pressure, and the oil cooler 2. In the hydraulic control device for an automatic transmission that outputs hydraulic oil to a predetermined part, when the pressure difference between the upstream side and the downstream side of the oil cooler 2 is larger than a predetermined threshold value, the hydraulic pressure on the upstream side of the oil cooler 2 is changed to the oil cooler. 2 is provided with a cooler bypass pipe line 6 that directly outputs to a predetermined portion without passing through 2, and the cooler bypass pipe line 6 is provided with a cooler bypass valve 7 composed of a switching valve, and upstream of the oil cooler 2. The input check valve 1 is disposed on the side, and the pressure difference between the upstream side of the input check valve 1 and the downstream side of the oil cooler 2 is predetermined. It is determined whether or not it is greater than a threshold value, and when the pressure difference between the upstream side of the input check valve 1 and the downstream side of the oil cooler 2 is greater than a predetermined threshold value, the hydraulic pressure on the upstream side of the input check valve 1 It is switched to output to.

  That is, it has an input check valve 1 that operates at a specific hydraulic pressure and flows hydraulic oil stored in the automatic transmission in a specific direction, and cools the hydraulic oil by heat exchange with the oil cooler 2. 3 and the oil pressure at both ends of the cooler pipe line 3 are taken in, and the pressure difference between the upstream side of the cooler pipe line 3, that is, the input port 1c of the input check valve 1 and the downstream side, that is, the output of the oil cooler 2 is detected. When the pressure difference between the upstream side and the downstream side of the cooler piping 3 is larger than a predetermined threshold value, the cooler bypass valve 7 that outputs the hydraulic pressure on the upstream side of the cooler piping 3 via the cooler bypass piping 6 is provided. It has.

The hydraulic control device for an automatic transmission according to the second embodiment configured as described above operates as follows.
In the initial stage of engine driving, the input check valve 1 is opened by a predetermined pressure of hydraulic oil as an oil cooler input output from an oil pump driven by the rotation of the turbine runner. Of course, the cooler bypass valve 7 takes in the hydraulic pressure at both ends of the series pipe line of the cooler pipe line 3 composed of the oil cooler 2 and the input check valve 1, and the pressure of the input port 1 c of the input check valve 1 and the output of the oil cooler 2. Since the difference is detected, since both inputs are small, the spring 7b of the cooler bypass valve 7 communicates the input port 7g of the cooler bypass valve 7 with the output port 7d.

  When the temperature of the hydraulic oil as an oil cooler input output from the oil pump increases due to the driving of the engine, the oil flow resistance decreases and the viscosity of the hydraulic oil decreases. Then, the fluidity of the hydraulic oil is increased, and a hydraulic pressure of a predetermined value or more is applied to the input check valve 1. When a hydraulic pressure higher than a predetermined value is applied to the input check valve 1, the hydraulic oil stored in the automatic transmission passes through the cooler piping 3 and is heat-exchanged and cooled by the oil cooler 2. The cooled hydraulic oil is communicated with the output port 7d by the input port 7g of the cooler bypass valve 7 by the oil pressure of the spring 7b and the pressure receiving port 7e of the cooler bypass valve 7, and the cooled hydraulic oil is transmitted to the clutch and brake of the transmission mechanism. Is output for lubrication.

  Here, when an abnormality such as an increase in fluid resistance for flowing hydraulic oil to the cooler piping 3, for example, an abnormality of the oil cooler 2, a failure of the input check valve 1, a foreign object clogging in the cooler piping 3, A difference occurs in the oil pressure at both ends of the cooler piping 3. Specifically, the oil pressure at the input port 1 c of the input check valve 1 is abnormally higher than the oil pressure at the output side of the oil cooler 2. A hydraulic pressure difference is generated in the pressure receiving port 7c of the cooler bypass valve 7 to press the piston 7a against the elastic force of the spring 7b and the hydraulic pressure of the other pressure receiving port 7e, and the input port 7f and the output port 7d communicate with each other. . Therefore, the hydraulic oil that passes through the cooler bypass piping 6 without passing through the oil cooler 2 is output for lubrication of clutches, brakes, and the like of the transmission mechanism.

  In this way, the input check valve 1 opens and closes depending on the temperature of the hydraulic oil as the oil cooler input, and the cooler bypass valve 7 takes in the oil pressure at both ends of the oil cooler 2 respectively. Since the pressure difference between the input port 1c and the oil cooler 2 output is detected, the input port 7f and the output port 7d of the cooler bypass valve 7 can be used regardless of whether both inputs are small or both inputs are large. The space remains closed. However, there is a difference in the oil pressure at both ends of the cooler piping 3, and the oil pressure that presses the piston 7 a against the pressure receiving port 7 c of the cooler bypass valve 7 against the elastic force of the spring 7 b and the oil pressure of the other pressure receiving port 7 e. When weakened, the input port 7f and the output port 5d communicate with each other, and hydraulic oil passing through the cooler bypass piping 6 is output without passing through the oil cooler 2. Therefore, the hydraulic oil is output for lubrication of the clutch, brake, etc. of the transmission mechanism without being cooled by the oil cooler 2.

The hydraulic control device for the automatic transmission according to the first embodiment and the second embodiment is based on the premise that the oil cooler output is single, but when the oil cooler output is not single. Has an input check valve 1 that operates at a specific hydraulic pressure and flows hydraulic oil contained in the automatic transmission in a specific direction, and cools the hydraulic oil by heat exchange with the oil cooler 2. 3 and the oil pressure at both ends of the cooler pipe line 3 are taken in, respectively, upstream of the serial line of the cooler pipe line 3 and the input check valve 1, that is, the input port 1c and the downstream side of the input check valve 1, that is, output When the pressure difference at the input port 4c of the check valve 4 is detected and the pressure difference between the upstream side and the downstream side of the cooler piping 3 is larger than a predetermined threshold value, It can be configured to cooler bypass valve 5 for outputting a hydraulic pressure on the upstream side of the cooler pipe line 3 through a chromatography bypass pipe passage 6.

Furthermore, the cooler piping 3 in the hydraulic control device for the automatic transmission according to the first and second embodiments is a piping having at least the input check valve 1 and the oil cooler 2. Therefore, the abnormality detection of the oil cooler 2 and the abnormality detection of the input check valve 1 can be performed, and the influence of the oil cooler input hydraulic pressure can be eliminated.

Furthermore, the hydraulic control device for the automatic transmission according to the first embodiment includes a cooler bypass piping 6 that outputs to a predetermined part such as a clutch and a brake of the transmission mechanism, and a downstream side of the oil cooler 2. Since the output check valve 4 for preventing the inflow from the cooler bypass pipe line 6 to the oil cooler 2 is provided, the reverse flow from the cooler bypass pipe line 6 to the oil cooler 2 can be prevented, and the downstream side of the oil cooler 2 can be prevented. Since the pressure does not fluctuate, the amount of oil in the cooler bypass piping 6 is stabilized and can be supplied to predetermined parts such as a clutch and a brake of the speed change mechanism. The output check valve 4 can also be disposed on the output side of the oil cooler 2 of the second embodiment.

FIG. 1 is a piping diagram showing a connection relationship of a hydraulic control device for an automatic transmission according to a first embodiment of the present invention. FIG. 2 is a piping diagram showing the connection relationship of the hydraulic control device for an automatic transmission according to the second embodiment of the present invention. FIG. 3 is a piping diagram for explaining the relationship between an oil cooler of a conventional hydraulic control device for an automatic transmission and its bypass system.

Explanation of symbols

1 Input Check Valve 2 Oil Cooler 3 Cooler Piping 4 Output Check Valve 5, 7 Cooler Bypass Valve 6 Cooler Bypass Piping

Claims (4)

A hydraulic control device for an automatic transmission that outputs hydraulic oil stored in the automatic transmission to an oil cooler via an input check valve that operates at a specific hydraulic pressure, and outputs the hydraulic oil from the oil cooler to a predetermined portion. In
An automatic transmission comprising: a cooler bypass pipe that outputs an oil pressure upstream of the oil cooler to the predetermined portion when a pressure difference between the upstream side and the downstream side of the oil cooler is larger than a predetermined threshold value. Hydraulic control device for the machine.   In the cooler bypass piping, the input check valve is disposed on the upstream side of the oil cooler, and when the pressure difference between the upstream side of the input check valve and the downstream side of the oil cooler is larger than a predetermined threshold value, The hydraulic control device for an automatic transmission according to claim 1, further comprising a cooler bypass valve that outputs an oil pressure upstream of the input check valve to the predetermined portion.   Whether the input check valve is disposed on the upstream side of the oil cooler in the cooler bypass piping, and whether the pressure difference between the upstream side of the input check valve and the downstream side of the oil cooler is greater than a predetermined threshold value. When the pressure difference between the upstream side of the input check valve and the downstream side of the oil cooler is larger than a predetermined threshold value, the hydraulic pressure upstream of the input check valve should be output to the predetermined part. The hydraulic control device for an automatic transmission according to claim 1, further comprising a switching valve for switching. An output check valve for preventing an inflow from the cooler bypass piping to the oil cooler is provided between the cooler bypass piping that outputs to the predetermined portion and a downstream side of the oil cooler. The hydraulic control device for an automatic transmission according to any one of claims 1 to 3.

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