JP2013194829A - Hydraulic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device which suppresses variations in oil quantity in an oil pan by using an existing space effectively.SOLUTION: A hydraulic control device is configured to reserve oil supplied to at least either of a hydraulic control subject part and a lubricating part in an oil pan 1 and to temporarily reserve a part of oil pumped up from the oil pan 1 in an accumulator 10 in which a back pressure is set up by an elastic force of an elastic member 16 accommodated in a back pressure chamber 11. The hydraulic control device is also equipped with an oil passage 12a for guiding oil, which has a pressure lower than that of oil supplied to the hydraulic control subject part, to the back pressure chamber 11, and a discharge regulation mechanism 18 for reducing an amount of oil flowing out from the back pressure chamber 11 to the oil pan 1 when the amount of oil in the oil pan 1 is large, and for increasing the amount of oil when the amount of oil in the oil pan 1 is small.

Description

  The present invention relates to a hydraulic apparatus capable of controlling the amount of oil in an oil pan that stores oil supplied to a hydraulic actuator, a lubrication site, and the like.

  An oil pan for storing oil is provided at the bottom of the transmission and transaxle mounted on the vehicle, and the oil stored in the oil pan is scraped up by a gear or pumped up by an oil pump. And the gear meshing surface of the transaxle or the sliding surface of the sliding member is supplied for lubrication. The oil pumped up from the oil pan by the oil pump and pressurized is supplied to a hydraulic actuator provided in a continuously variable transmission, a hydraulic clutch or the like, and further supplied to an accumulator that temporarily stores hydraulic pressure. Sometimes.

  Patent Document 1 describes a device that controls the hydraulic pressure of a hydraulic actuator provided in a belt-type continuously variable transmission, a clutch, a brake, or the like. The hydraulic control device described in Patent Document 1 includes an accumulator that communicates with a hydraulic chamber of a brake that is engaged when the vehicle travels backward. The accumulator includes an input port communicating with a hydraulic chamber of the brake, and a supply port formed facing the input port and communicated with a lubricating pressure oil passage. And a spring that presses toward the input port. And according to the hydraulic control apparatus described in Patent Document 1, by controlling so that the hydraulic pressure supplied to the space on the supply port side is increased, pressure is accumulated only when the hydraulic pressure on the input port side is high, It is said that the shock when the brake is engaged can be suppressed.

  Patent Document 2 describes a control valve that includes a port communicating with a clutch discharge passage and a port communicating with a back pressure chamber in an accumulator. The control valve is configured to control the oil drain resistance of the clutch and to control the back pressure of the accumulator.

JP-A-3-223565 JP-A-7-54978

  In a configuration in which an accumulator that supplies hydraulic pressure to a hydraulic actuator or a hydraulic clutch is provided as in the hydraulic control device described in Patent Document 1, the oil amount of the oil pan is set according to the amount of oil accumulated in the accumulator. Change. Therefore, for example, if the amount of pressure stored in the accumulator is small, the amount of oil stored in the oil pan increases, and a part of one of the gears in the transmission or transaxle is immersed in the oil stored in the oil pan. Since the gear is stirred by the rotation of the gear, the loss due to the viscous resistance of the oil may increase. On the other hand, if the amount of pressure accumulated in the accumulator is large, if the amount of oil stored in the oil pan is small, the amount of oil pumped up by the gear will decrease, and the amount of oil supplied to the lubrication site will decrease. There was a possibility.

  The present invention has been made against the background described above, and it is an object of the present invention to provide a hydraulic control device capable of effectively utilizing an existing space and suppressing fluctuations in the amount of oil in an oil pan. Is.

  In order to achieve the above object, the invention of claim 1 stores oil supplied to at least one of the hydraulic control target part and the lubrication part in the oil pan, and the oil pumped from the oil pan. In the hydraulic control apparatus configured to temporarily store a part in an accumulator in which the back pressure is set by the elastic force of the elastic member housed in the back pressure chamber, the oil supplied to the hydraulic control target unit An oil passage for guiding oil of a lower pressure to the back pressure chamber, and the amount of oil flowing out from the back pressure chamber to the oil pan is reduced when the oil amount in the oil pan is large and in the oil pan And a discharge adjusting mechanism that increases when the amount of oil is small.

  According to a second aspect of the present invention, in the first aspect of the present invention, the exhaust pan further includes a discharge oil passage that allows the back pressure chamber to communicate with the oil pan, and the discharge adjustment mechanism is configured to perform the discharge when the amount of oil in the oil pan is large. The hydraulic control device includes a valve mechanism that reduces the opening of the oil passage and increases the opening of the oil discharge passage when the amount of oil in the oil pan is small.

  According to a third aspect of the present invention, in the second aspect of the present invention, the valve mechanism floats on the oil in the oil pan and rises as the oil level of the oil pan rises to open the opening area of the drain oil passage And a float that descends as the oil level of the oil pan descends to increase the opening area of the discharge passage.

  According to a fourth aspect of the present invention, in the second aspect of the present invention, the valve mechanism includes an electromagnetic on-off valve provided in the middle of the oil discharge passage, a sensor for detecting the amount of oil in the oil pan, and the sensor And a controller that changes an opening degree of the electromagnetic on-off valve in accordance with a detection signal.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, the exhaust oil passage further connecting the back pressure chamber to the oil pan is provided, and the exhaust adjustment mechanism is disposed in the exhaust oil passage, and the temperature of the oil Including a thermally expandable plug that expands in response to an increase in the flow rate to reduce the opening cross-sectional area of the exhaust oil passage and contracts in response to a decrease in oil temperature to increase the cross-sectional area in the discharge oil passage. Is a hydraulic control device characterized by

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the oil having a lower pressure than the oil supplied to the hydraulic control target unit regulates the hydraulic pressure supplied to the hydraulic control target unit. The oil pressure control apparatus includes oil whose primary pressure is drain oil generated along with the oil pressure.

  In this invention, since the accumulator is configured to have the elastic force of the elastic member as the back pressure, the back pressure chamber in which the elastic member is accommodated is a space portion excluding the elastic member, Oil is introduced into the space and stored. The oil is a lower pressure oil than the oil to be supplied to the hydraulic control target part, more specifically a drain oil. Therefore, the back pressure of the accumulator does not change in particular, and the amount of oil in the oil pan Can be reduced according to the amount of oil stored in the back pressure chamber. As a result, the oil level in the oil pan is lowered, so that oil agitation and power loss caused by the oil can be reduced. The oil in the back pressure chamber is supplied to the oil pan, and the amount thereof is adjusted according to the amount of oil in the oil pan. That is, if the amount of oil in the oil pan is reduced, the amount of oil discharged from the back pressure chamber is increased. On the other hand, if the amount of oil in the oil pan is increased, the oil discharged from the back pressure chamber is increased. The amount of is reduced. Therefore, fluctuations in the oil amount or the oil level of the oil pan are reduced, and it is possible to avoid or suppress the oil in the oil pan from being excessively agitated and accompanying with the increase in power loss.

  In particular, in the configuration described in claim 3, the amount of oil discharged from the back pressure chamber can be automatically adjusted without requiring special control equipment and without performing special control. .

  According to the configuration described in claim 4, the amount of oil discharged from the back pressure chamber or the amount of oil in the oil pan can be adjusted more accurately.

  On the other hand, according to the configuration described in claim 5, when the temperature of the oil is high, the viscosity of the oil decreases and the amount of oil returning to the oil pan increases. In this case, the back pressure chamber Since the amount of oil discharged from the oil pan is reduced, the increase in the amount of oil in the oil pan can be suppressed.On the contrary, when the temperature is low, the viscosity of the oil increases and the oil pan In this case, the amount of oil discharged from the back pressure chamber is increased, so that a decrease in the amount of oil in the oil pan can be suppressed. As a result, the oil in the oil pan is reduced. Variation in quantity or oil level can be reduced.

It is a figure for demonstrating an example of the hydraulic control apparatus which concerns on this invention. It is a figure which shows the hydraulic circuit which supplies oil to each site | part in a transmission with an oil pump. It is a figure for demonstrating the other example of the hydraulic control apparatus which concerns on this invention. It is a figure for demonstrating the further another example of the hydraulic control apparatus which concerns on this invention.

  The hydraulic control apparatus according to the present invention is capable of controlling the amount of oil in an oil pan provided at the lower part of a transmission or a transaxle (hereinafter referred to as a transmission) mounted on a vehicle. That is, the gear train and the hydraulic actuator in the transmission are housed in a single case, and an oil pan is provided below the gear train. The oil pan stores oil to be supplied to a lubrication site such as a meshing surface of a gear and a sliding surface of a sliding member and a hydraulic control target unit such as a hydraulic actuator. The oil stored in the oil pan is scraped up by a gear partly immersed in the oil pan, or pumped up by an oil pump driven by an engine or an electric motor, and supplied to a lubrication part or a hydraulic control target unit. Further, the oil supplied to the lubrication site or the hydraulic control target part is dropped from the lubrication site or flows through a discharge oil passage in the lubrication site or the hydraulic control target unit and is discharged to the oil pan. That is, the oil in the oil pan circulates inside the transmission case.

  FIG. 2 shows a hydraulic circuit that supplies oil to each part of the transmission by means of an oil pump. The hydraulic circuit shown in FIG. 2 is configured to pump oil stored in the oil pan 1 by an oil pump 2 and supply it to each part. Specifically, the oil pumped up by the oil pump 2 is supplied to the lubrication parts 4 and 5 via a pressure regulating valve 3 which will be described later, and the oil is supplied to the hydraulic control target unit 7 via a check valve 6. It is configured to be.

  Here, the configuration of the hydraulic circuit shown in FIG. 2 will be specifically described. The hydraulic circuit shown in FIG. 2 is provided with a pressure regulating valve 3 for regulating the hydraulic pressure supplied to the hydraulic control target unit 7. Specifically, the pressure regulating valve 3 is provided in the oil passage 8 through which the oil discharged from the oil pump 2 flows. The pressure regulating valve 3 may be any valve that can regulate the oil pressure of the oil passage 8, and various valves such as an electromagnetic valve and a mechanical valve can be used.

  The hydraulic pressure regulated by the pressure regulating valve 3 is the original pressure of the hydraulic control target unit 7 and is supplied to the hydraulic control target unit 7 via the check valve 6. Specifically, the oil passage 8 branches and communicates with the hydraulic control target unit 7, and a check valve 6 is provided in the branched oil passage 9. The check valve 6 is formed so that the hydraulic pressure is supplied to the hydraulic control target unit 7 when the hydraulic pressure of the hydraulic control target unit 7 is lower than the hydraulic pressure of the oil path 9. An accumulator 10 for accumulating hydraulic pressure is provided on the output side of the check valve 6 in FIG. The accumulator 10 is provided to supply the accumulated hydraulic pressure to the hydraulic control target unit 7 when the oil pump 2 is not driven or when the hydraulic pressure of the hydraulic control target unit 7 is transiently increased. Yes. Note that the hydraulic control target unit 7 may be provided with a control valve that increases or decreases the hydraulic pressure of the hydraulic actuator. That is, a control valve for opening and closing the oil passage and supplying the oil pressure of the oil passage 9 to the hydraulic actuator to increase the pressure may be provided in the oil passage communicating with the oil passage 9 and the hydraulic actuator.

  On the other hand, the pressure regulating valve 3 is opened in order to reduce the oil pressure in the oil passage 8, and the oil discharged from the output port 3 a of the pressure regulating valve 3 flows into the lubrication parts 4 and 5 and the back pressure chamber 11 of the accumulator 10. The fluid is supplied through the oil passage 12. The oil passage 12 is provided with a variable relief valve 13, which opens when the oil pressure in the oil passage 12 increases during a failure or the like, and discharges the oil in the oil passage 12 to the oil pan 1. Is configured to do.

  The hydraulic circuit shown in FIG. 2 changes the amount of oil stored in the oil pan 1 in accordance with the amount of oil supplied to the accumulator 10, the hydraulic control target unit 7 or the lubrication parts 4, 5. The hydraulic control device is configured so that the amount of oil stored in the oil pan 1 can be controlled to be constant. Specifically, when the amount of oil stored in the oil pan 1 is small, the oil is discharged from the accumulator 10, and when the amount of oil stored in the oil pan 1 is large, the oil is stored in the accumulator 10. Has been.

  Here, the structure of the accumulator 10 shown in FIG. 2 is demonstrated concretely. The accumulator 10 shown in FIG. 2 is an oil formed by branching a hydraulic chamber 14 to which hydraulic pressure is supplied from an oil passage 9 communicating with the hydraulic control target unit 7 and an oil passage 12 through which the drain hydraulic pressure of the pressure regulating valve 3 flows. Oil is supplied from the passage 12 a and the piston 15 separates the back pressure chamber 11 that stores the supplied oil. More specifically, the hydraulic port 14a that opens downward and the supply port 11a that opens upward are formed in the accumulator 10, and the piston 15 extends vertically in the center in the axial direction of the accumulator 10. It is arranged so that it can move. That is, the piston 15 is disposed so that the space below the piston 15 becomes the hydraulic chamber 14 and the space above the back pressure chamber 11. A spring 16 that applies a load to the lower side is provided on the upper surface of the piston 15. Therefore, if the load based on the hydraulic pressure of the hydraulic chamber 14 is larger than the spring force acting on the piston 15, the piston 15 moves upward and the volume of the hydraulic chamber 14 increases. That is, the amount of oil accumulated in the accumulator 10 increases. On the contrary, if the load based on the hydraulic pressure of the hydraulic chamber 14 is smaller than the spring force acting on the piston 15, the piston 15 moves downward and the volume of the hydraulic chamber 14 decreases. That is, the amount of oil accumulated in the accumulator 10 decreases. The accumulator 10 configured as described above is configured such that oil having a relatively low pressure discharged from the pressure regulating valve 3 is supplied to the back pressure chamber 11. Therefore, the accumulator 10 is set with a hydraulic pressure that accumulates pressure based on the spring force. In other words, the hydraulic pressure accumulated in the accumulator 10 does not change according to the amount of oil supplied to the back pressure chamber 11.

  On the other hand, a drain port 11 b for discharging the oil supplied to the back pressure chamber 11 to the oil pan 1 is formed in the back pressure chamber 11. More specifically, the drain port 11b is formed on the side wall surface above the upper limit position where the piston 15 rises when the oil pressure of the oil passage 9, that is, the line pressure reaches the maximum value. That is, the oil supplied to the hydraulic chamber 14 is not discharged from the drain port 11b. The oil discharged from the drain port 11b flows through an oil passage 17 disposed above the oil pan 1 and opened toward the oil surface, and is discharged to the oil pan 1. The oil passage 17 corresponds to the exhaust oil passage in the present invention.

  Furthermore, as shown in FIG. 1, a float 18 is provided that can open and close the opening 17 a of the oil passage 17 communicating with the drain port 11 b. The float 18 is floating in the oil of the oil pan 1, and when the amount of oil stored in the oil pan 1 is small and the oil level is low, the float 18 is separated from the opening 17a, thereby opening the opening 17a. Is opened and oil is discharged from the accumulator 10. That is, the amount of oil stored in the oil pan 1 increases. Further, when the amount of oil stored in the oil pan 1 is large and the oil level is high, the float 18 is disposed so as to be fitted and sealed in the opening 17 a of the oil passage 17. In FIG. 1A, the amount of oil stored in the oil pan 1 is small, and the oil stored in the back pressure chamber 11 of the accumulator 10 flows out to the oil pan 1 when the float 18 moves away from the opening 17a. As a result, the oil accumulated in the back pressure chamber 11 is decreasing. Further, FIG. 1B shows a state in which the amount of oil stored in the oil pan 1 is large, and the oil is stored in the back pressure chamber 11 of the accumulator 10 by the float 18 sealing the opening 17a. Show.

  As shown in FIG. 1, when the amount of oil stored in the oil pan 1 is small, the oil supplied to the back pressure chamber 11 of the accumulator 10 is discharged to the oil pan 1 to be stored in the oil pan 1. The amount of oil can be increased. As a result, it is possible to suppress or prevent a reduction in the amount of oil scooped up from the oil pan 1 by a gear (not shown), and improve the lubricity of the lubrication parts 4 and 5. Further, when the amount of oil stored in the oil pan 1 is large, the oil supplied from the oil passage 12a to the accumulator 10 is stored in the accumulator 10 by sealing the opening 17a of the oil passage 17, and the oil pan It is possible to suppress or prevent the amount of oil stored in 1 from increasing. As a result, it is possible to reduce the agitation loss and the power loss resulting therefrom when the oil is scraped up by the gear. Even when the amount of oil in the oil pan 1 is large, the oil is supplied by the oil pump 2 to the hydraulic control target unit 7 and the lubrication parts 4 and 5, so that the oil in the oil pan 1 decreases and the oil pan 1 The oil stored in 1 does not increase excessively. Further, by setting the valve for opening and closing the oil passage 17 to the float 18, the oil passage 17 can be opened and closed following the amount of oil stored in the oil pan 1, so that a special for opening and closing the oil passage 17 is provided. It is possible to automatically adjust the amount of oil stored in the oil pan 1 without requiring a special control device and without performing special control.

  The above-described configuration is configured so that the oil stored in the accumulator 10 is not discharged to the oil pan 1 by sealing the float 18 in the opening 17a. However, as shown in FIG. It may be provided to electrically control the opening / closing operation of the electromagnetic valve 19. Here, the configuration shown in FIG. 3 will be described. First, the oil pan 1 is provided with a sensor 20 that detects the amount of stored oil. The sensor 20 is configured to detect the oil level of the oil, and the oil level detected by the sensor 20 is input as an electrical signal to a controller 21 electrically connected to the sensor 20. The The sensor 20 may be a sensor configured to constantly detect the oil level height and output a signal, and when the oil level height is other than a predetermined allowable oil level height. The sensor may be configured to output a signal.

  The oil passage 17 is provided with an electromagnetic valve 19 that can control the state in which the oil passage 17 communicates and the state in which the oil passage 17 does not communicate according to the energized power. The electromagnetic valve 19 is electrically connected to the controller 21. Therefore, electric power corresponding to the oil level detected by the sensor 20 is output from the controller 21, and the electromagnetic valve 19 is opened and closed according to the electric power. Here, an example of the electromagnetic valve 19 will be briefly described. The electromagnetic valve 19 includes a spring that presses one end of the spool, and a coil that generates an electromagnetic force that opposes the spring. By generating electromagnetic force, the spool moves in the direction of compressing the spring and can be opened.

  As described above, the amount of oil stored in the oil pan 1 can be controlled by detecting the oil level height of the oil pan 1 and opening and closing the electromagnetic valve 19 according to the oil level height. That is, when the oil level is low, the solenoid valve 19 is energized and opened to discharge the oil from the accumulator 10 to the oil pan 1 and increase the amount of oil stored in the oil pan 10. it can. As a result, it is possible to suppress or prevent a reduction in the amount of oil scooped up from the oil pan 1 by the gear, and improve the lubricity of the lubrication parts 4 and 5. On the contrary, when the oil level is high, by closing the solenoid valve 19 without energizing the oil, the oil is stored in the accumulator 10 and the amount of oil stored in the oil pan 1 increases. It can be suppressed or prevented. As a result, it is possible to reduce the agitation loss and the power loss resulting therefrom when the oil is scraped up by the gear. Further, since the oil level is detected by the sensor 20, the amount of oil stored in the oil pan 1 can be adjusted with high accuracy.

  In each of the above-described configuration examples, the oil pan 1 is configured to switch whether or not the oil is discharged from the accumulator 10 according to the amount of oil stored in the oil pan 1. You may comprise so that oil may be discharged from the accumulator 10 without detecting. An example of the configuration is shown in FIG. The example shown in FIG. 4 is configured to switch whether or not to discharge oil from the accumulator 10 according to the temperature of the oil. That is, when the temperature of the oil is low, the viscosity of the oil increases, so that the oil adheres to the wall surface of the case and the amount of oil discharged to the oil pan 1 decreases, so that the oil pan 1 from the accumulator 10 decreases. It is configured to drain oil. FIG. 4A shows a state where the oil temperature is low, and FIG. 4B shows a state where the oil temperature is high.

  The configuration will be specifically described. In the configuration shown in FIG. 4, a member 22 that expands and contracts due to temperature, more specifically, a plug 22 is provided inside the oil passage 17. The plug 22 is formed so that when the oil temperature is high, the oil passage 17 is closed and the oil does not flow due to thermal expansion, and when the oil temperature is low, the plug 22 contracts to open the oil passage 17 and the oil flows. Has been. That is, the plug 22 can function as a valve that opens and closes the oil passage 17 according to the temperature of the oil. That is, as shown in FIG. 4A, when the temperature of the oil is low, the plug 22 contracts and the oil passage 17 is opened, whereby the oil in the accumulator 10 is discharged to the oil pan 1. FIG. 4A shows a state in which the oil accumulated in the accumulator 10 is reduced due to the oil in the accumulator 10 being discharged. On the contrary, as shown in FIG. 4B, when the temperature of the oil is high, the plug 22 expands and the oil passage 17 is closed, so that the oil is not discharged from the accumulator 10, Oil is stored in the accumulator 10. FIG. 4B shows a state in which the oil accumulated in the accumulator 10 is increasing because the oil in the accumulator 10 is not discharged.

  As shown in FIG. 4, when it is assumed that the amount of oil stored in the oil pan 1 is small, that is, when the oil temperature is low, the oil passage 17 is opened and the oil is discharged from the accumulator 10 to the oil pan 1. By doing so, the amount of oil stored in the oil pan 1 can be increased. As a result, it is possible to suppress or prevent a reduction in the amount of oil scooped up from the oil pan 1 by the gear, and improve the lubricity of the lubrication parts 4 and 5. On the contrary, when it is assumed that the amount of oil stored in the oil pan 1 is large, that is, when the oil temperature is high, the oil passage 1 is closed and the oil is stored in the accumulator 10 to thereby store the oil pan 1. It is possible to suppress or prevent an increase in the amount of oil stored in the tank. As a result, it is possible to reduce the agitation loss and the power loss resulting therefrom when the oil is scraped up by the gear.

  The amount of oil stored in the oil pan 1 can be controlled by opening and closing the oil passage 17 connected to the drain port 11 b of the accumulator 10 by the float 18, the electromagnetic valve 19, or the plug 22 described above. That is, when the amount of oil stored in the oil pan 1 is small, the amount of oil stored in the oil pan 1 can be increased by discharging the oil to the oil pan 1 through the accumulator 10. On the other hand, when the amount of oil stored in the oil pan 1 is large, the accumulator 10 functions as a tank for temporarily storing oil by closing the oil passage 17 and is stored in the oil pan 1. It is possible to suppress or prevent the oil amount from increasing. As a result, since the amount of oil stored in the oil pan 1 can be set to an appropriate amount, the amount of the gear immersed in the oil stored in the oil pan 1 is reduced or agitated when it is scraped up. Loss and power loss caused by the loss can be increased.

  Note that the hydraulic control device according to the present invention may be configured so that oil is discharged from the back pressure chamber 11 in the accumulator 10 according to the amount of oil stored in the oil pan 1, and thus the oil path 17 may be provided with a valve for opening and closing the drain port 11b. Further, when the oil passage 17 is provided as in each of the above-described configurations, it is only necessary to include a valve that can open and close the oil passage 17, so that the oil passage 17 is provided by the float 18 or the electromagnetic valve 19 described above. May be added to the configuration for opening and closing the oil passage 17 by thermal expansion or contraction according to the oil temperature.

  DESCRIPTION OF SYMBOLS 1 ... Oil pan, 2 ... Oil pump, 3 ... Pressure regulating valve, 7 ... Hydraulic control object part, 8, 9, 12, 12a, 17 ... Oil path, 10 ... Accumulator, 11 ... Back pressure chamber, 11b ... Drain port, 14 ... Hydraulic chamber, 18 ... Float, 19 ... Solenoid valve, 22 ... Plug.

Claims (6)

The oil supplied to at least one of the hydraulic control target part and the lubrication part is stored in the oil pan, and a part of the oil pumped from the oil pan is elasticized by the elastic member accommodated in the back pressure chamber. In the hydraulic control device configured to temporarily store in the accumulator in which the back pressure is set by
An oil passage for guiding oil having a pressure lower than oil supplied to the hydraulic control target part to the back pressure chamber;
A discharge adjustment mechanism that reduces the amount of oil flowing out from the back pressure chamber to the oil pan when the amount of oil in the oil pan is large and increases when the amount of oil in the oil pan is small. A hydraulic control device characterized by that. A drain oil passage for communicating the back pressure chamber with the oil pan;
The discharge adjustment mechanism includes a valve mechanism that reduces the opening of the discharge oil passage when the amount of oil in the oil pan is large and increases the opening of the discharge oil passage when the amount of oil in the oil pan is small. The hydraulic control device according to claim 1.   The valve mechanism floats on the oil in the oil pan, rises as the oil level of the oil pan rises to reduce the opening area of the drain oil passage, and as the oil level of the oil pan falls. The hydraulic control device according to claim 2, further comprising a float that descends to increase an opening area of the discharge passage.   The valve mechanism includes an electromagnetic on-off valve provided in the middle of the oil discharge passage, a sensor for detecting the amount of oil in the oil pan, and an opening degree of the electromagnetic on-off valve according to a detection signal of the sensor. The hydraulic control device according to claim 2, further comprising: A drain oil passage for communicating the back pressure chamber with the oil pan;
The discharge adjustment mechanism is disposed in the discharge oil passage, expands in response to an increase in oil temperature, reduces an opening cross-sectional area of the discharge oil passage, and contracts in response to a decrease in oil temperature to discharge the discharge. The hydraulic control device according to claim 1, further comprising a thermally expandable plug that increases an opening cross-sectional area of the oil passage.   Oil having a pressure lower than that of oil supplied to the hydraulic control target unit includes oil whose main pressure is drain oil that is generated when the hydraulic pressure supplied to the hydraulic control target unit is regulated. The hydraulic control device according to any one of claims 1 to 5.

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