JP2013241956A - Hydraulic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device capable of shortening time from valve opening control start time to actual valve opening.SOLUTION: A hydraulic control device includes an opening and closing valve 1 with an output port 6 for outputting oil pressure supplied from an oil pressure source 2 to a hydraulically-controlled part 3, a valve element 12 for closing the output port 6, a piston 10 moving according to a pressure difference of oil pressures acting on both of the front and back sides thereof integral with the valve element 12, and an input port 5 formed and communicated with the oil pressure source 2 so that the oil pressure supplied from the oil pressure source 2 acts on the surface 11 of the piston 10. Moreover, the hydraulic control device includes an elastic member 14 which applies an elastic force to the piston 10 in a direction where the valve element 12 separates from the output port 6, a communication part 13 with a throttle for making the oil pressure acting on both of the front and back sides of the piston 10 communicated, and decompression mechanisms 18, 19, 20 which selectively decompress the oil pressure acting on a back surface 15 of the piston 10.

Description

  The present invention relates to a hydraulic control device configured to suppress or prevent leakage of oil from a valve by bringing a valve body into contact with an output port, and particularly includes an elastic member that biases the valve body to one side. The present invention relates to a hydraulic control device.

  The hydraulic pressure of the hydraulic actuator mounted on the vehicle is configured to be controlled using the hydraulic pressure output from the hydraulic power source as a source pressure. Therefore, by suppressing or preventing the leakage of oil from the hydraulic control device provided to control the hydraulic pressure of the hydraulic actuator, the drive frequency of the hydraulic power source can be reduced, and consequently the fuel consumption can be reduced. it can. As an example of such a hydraulic control device, a poppet-type electromagnetic valve configured to close an output port by bringing a valve body into contact with the output port is known. A conventionally known poppet-type solenoid valve acts to apply the hydraulic pressure supplied from a hydraulic power source to one end of the valve body and to press the valve body to the output port side by the elastic force of the elastic member. In addition, an electromagnetic force corresponding to the electric power supplied to the solenoid is configured to act in a direction in which the valve body is separated from the output port. Therefore, the load based on the hydraulic pressure of the hydraulic actuator, the load based on the hydraulic pressure supplied from the hydraulic source, the elastic force of the elastic member, and the electromagnetic force act on the valve body, and the output port is opened and closed by the balance of those loads. Is configured to do. In other words, the output port is configured to open and close by controlling the power supplied to the solenoid.

  Patent Document 1 describes a poppet type valve configured to apply an elastic force of an elastic member in a direction in which a valve body is separated from an output port. The poppet type valve described in Patent Document 1 includes a flow control valve body that prevents a flow of fluid by contacting the output port, a stepping motor that moves the flow control valve body in the axial direction, and an output port. When a plurality of bypass valve ports formed at predetermined intervals in the circumferential direction on the outer circumferential side of the cylinder and the flow control valve body move to the output port side, the fluid control valve body is pressed to the output port side. And an on-off valve body that abuts the bypass valve port to prevent the flow of fluid, and a spring that biases the on-off valve body in a direction away from each port. Therefore, by driving the stepping motor and moving the flow control valve body toward the output port, the output port is closed, and the open / close valve body is configured to close the bypass port valve port, on the contrary, By moving the fluid control valve body in a direction away from the output port, the output port is opened, and the open / close valve body is pressed by a spring to open the bypass valve port. That is, the spring is arranged so that the on-off valve body moves integrally with the fluid control valve body, and functions as a so-called return spring.

  On the other hand, Patent Document 2 describes a poppet-type electromagnetic valve having an elastic member that presses the valve body toward the output port. This poppet-type electromagnetic valve is configured such that a source pressure is supplied to a space on the side where the valve body comes into contact with the output port. Further, the valve body is formed with a bypass path communicating with both end sides in the axial direction. Through the bypass path, the back side of the valve body, that is, the end side opposite to the end contacting the output port Is configured to be supplied with a source pressure. Furthermore, an elastic member that presses the valve body toward the output port from the rear side of the valve body is provided. A pilot valve that can reduce the hydraulic pressure on the rear side of the valve body is provided, and by opening the pilot valve, the hydraulic pressure on the rear side of the valve body is reduced to separate the valve body from the output port. It is configured to let you. The pilot valve is configured to move by a solenoid, and when the pilot valve is opened, the working fluid output from the rear side of the valve body communicates between the output port and the actuator. Is configured to do.

JP 2006-242502 A JP 2011-241904 A

  The poppet type valve described in Patent Document 1 is configured such that an output port and a bypass valve port are opened and closed when a stepping motor is driven. Therefore, when the poppet type valve described in Patent Document 1 is used as a hydraulic control valve, the driving of the stepping motor is controlled according to the hydraulic pressure supplied to the hydraulic control target unit, so that the control is complicated. Alternatively, there is a possibility that it may become complicated, or there is a possibility that the controllability of the hydraulic pressure of the hydraulic control target unit will be reduced.

  On the other hand, in the poppet type solenoid valve described in Patent Document 2, since the valve body is pressed to the output port side by the pressing member, the difference in load based on the hydraulic pressure acting on both the front and back surfaces of the valve body is The valve body is configured to be separated from the output port when the elastic force acting on the valve becomes greater than the elastic force. Therefore, even if the pilot valve is opened to reduce the hydraulic pressure behind the valve body, the valve body may not be separated from the output port when the hydraulic pressure behind the valve body starts to decrease. For this reason, there is a possibility that it takes time from when the control is started to open the valve until the output port is actually opened and the hydraulic pressure of the hydraulic control target portion changes.

  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 that can shorten the time from the start of valve opening control to the actual valve opening. .

  In order to achieve the above object, an invention according to claim 1 is directed to an output port that outputs hydraulic pressure supplied from a hydraulic pressure source to a hydraulic control target unit, and a valve body that contacts the output port and closes the output port. The piston that moves integrally with the valve body according to the pressure difference of the hydraulic pressure acting on both the front and back sides, and the hydraulic pressure supplied from the hydraulic source acts on the surface of the piston on the side where the valve body is provided In the hydraulic control apparatus having an on-off valve having an input port formed in communication with the hydraulic power source, an elastic member that applies an elastic force to the piston in a direction in which the valve body separates from the output port And a pressure-reducing portion that selectively connects the pressure acting on both the front and back sides of the piston, and the pressure acting on the back surface of the piston opposite to the surface on which the valve element is provided. Do And it is characterized in that it comprises a pressure mechanism.

  According to a second aspect of the present invention, in the first aspect of the invention, when the hydraulic pressure is started to be supplied to the on-off valve, the hydraulic pressure supplied from the hydraulic source to the on-off valve is changed to a state in which the piston closes the output port. The hydraulic control apparatus is characterized by temporarily increasing the hydraulic pressure that can be maintained.

  A third aspect of the present invention is the hydraulic control apparatus according to the first or second aspect, wherein the hydraulic pressure discharged from the pressure reducing mechanism is supplied to the hydraulic control target unit. is there.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the pressure reducing mechanism includes a discharge portion that discharges hydraulic pressure supplied to the back side of the piston, a pilot valve that closes the discharge portion, And a solenoid that opens and closes the discharge portion by applying an electromagnetic force to the pilot valve when energized.

  According to the first aspect of the present invention, the piston moves in accordance with the pressure difference between the hydraulic pressures acting on the front and back surfaces of the piston, and the valve body moves integrally with the piston. Therefore, depending on the pressure difference of the oil pressure acting on the front and back surfaces of the piston, the valve body abuts the output port and closes the output port, or the oil pressure supplied from the hydraulic source away from the output port is supplied to the hydraulic control target part You can do it. In addition, since the elastic force of the elastic member acts on the piston in the direction in which the valve element is separated from the output port, the valve element moves in the direction away from the output port when a pressure difference between the hydraulic pressure acting on both the front and back surfaces of the piston occurs. can do. That is, the time from the start of the valve opening control to the actual valve opening can be shortened. Therefore, the hydraulic response of the hydraulic control target unit can be improved. Furthermore, a communication part with a throttle for communicating the hydraulic pressure acting on both the front and back sides of the piston and a pressure reducing mechanism for reducing the hydraulic pressure acting on the back surface of the piston opposite to the surface on which the valve body is provided are provided. Therefore, the same hydraulic pressure can be applied to both the front and back surfaces of the piston, and the piston can be moved in a direction away from the output port by reducing the hydraulic pressure acting on the back surface by the pressure reducing mechanism. it can. That is, the opening / closing operation of the output port can be controlled by controlling the pressure reducing mechanism to control the hydraulic pressure acting on the back surface of the piston.

  According to the invention of claim 2, when the hydraulic pressure is started to be supplied to the on-off valve, the hydraulic pressure supplied from the hydraulic source to the on-off valve is temporarily higher than the hydraulic pressure at which the piston can maintain the output port closed. Therefore, even when the hydraulic pressure is not supplied to the on-off valve and the valve body is separated from the output port, when the hydraulic pressure is started to be supplied to the on-off valve, high hydraulic pressure is supplied from the hydraulic source. Thus, the hydraulic pressure of the hydraulic control target part and the on-off valve can be increased at an early stage. As a result, it is possible to increase the hydraulic pressure of the hydraulic control target part at an early stage and to supply a high hydraulic pressure from the on-off valve when there is a pressure increase request of the hydraulic control target part. The hydraulic response of the part can be improved. Further, by increasing the hydraulic pressure supplied to the on-off valve, the pressure loss of the hydraulic pressure supplied from the hydraulic source can be increased, and the increase in the on-off valve hydraulic pressure is promoted, and the output port can be closed early. it can.

  According to the invention of claim 3, since the hydraulic pressure discharged from the pressure reducing mechanism is configured to be supplied to the hydraulic pressure control target portion, when the hydraulic pressure on the back side of the piston is reduced to move the piston, Even so, the hydraulic pressure discharged to reduce the pressure can be supplied to the hydraulic control target unit. Further, since the output port is opened by reducing the oil pressure on the back side of the piston, the oil pressure discharged along with the pressure reduction and the oil pressure output from the output port can be supplied to the hydraulic control target unit. As a result, the substantial opening area for supplying the hydraulic pressure to the hydraulic control target part can be increased, and the hydraulic response of the hydraulic control target part can be improved.

  According to the invention of claim 4, the pressure reducing mechanism causes an electromagnetic force to act on the pilot valve by energizing the discharge part for discharging the hydraulic pressure supplied to the back side of the piston, the pilot valve for closing the discharge part. Therefore, by controlling the electric power supplied to the solenoid, it is possible to control the opening / closing of the discharging unit, and as a result, the opening / closing operation of the opening / closing valve can be controlled.

It is a figure for demonstrating an example of a structure of the hydraulic control apparatus which concerns on this invention. 2 is a flowchart for explaining an example of control when the hydraulic control device shown in FIG. 1 is mounted on a vehicle.

  Next, an example of a hydraulic control device according to the present invention will be described. FIG. 1 shows a poppet-type solenoid valve that can be a target of the hydraulic control device according to the present invention. A solenoid valve 1 shown in FIG. 1 controls a hydraulic pressure of a hydraulic actuator 3 that is a hydraulic control target unit using a hydraulic pressure supplied from a hydraulic pressure source 2 as a source pressure. In FIG. An electromagnetic valve 1 is provided so as to control the hydraulic pressure of a hydraulic actuator 3 attached to one pulley 4 in the continuously variable transmission.

  The hydraulic power source 2 shown in FIG. 1 may be a mechanical oil pump that is driven by the power of any rotating member in a power transmission path that transmits power from a power source such as an internal combustion engine or an electric motor to drive wheels. An electric oil pump driven by an electric motor may be used. The oil pressure output from the hydraulic pressure source 2 is regulated by a pressure regulating valve (not shown). As the pressure regulating valve, a regulator valve configured to regulate the hydraulic pressure of oil output from the hydraulic pressure source based on a signal pressure corresponding to an accelerator opening, a braking force, or the like can be used.

  Here, the configuration of the electromagnetic valve 1 shown in FIG. 1 will be specifically described. The electromagnetic valve 1 shown in FIG. 1 includes an input port 5 that communicates with a hydraulic source 2 and an output port 6 that communicates with a hydraulic actuator 3. Specifically, the input port 5 is formed on the side wall surface of the housing 7 formed in a bottomed cylindrical shape, and the output port 6 is formed in the lid 8 that seals the opening in the housing 7. Further, the output port 6 is configured to be closed when a valve body 12 (to be described later) abuts from the inside of the housing 7, so that the opening on the inside of the housing 7 in the output port 6 The cross-sectional area is formed in a tapered shape toward the surface, and the tapered surface functions as the valve seat 9.

  A disk-shaped piston 10 is provided inside the housing 7. The piston 10 defines the interior of the housing 7 and is arranged so as to move in the axial direction within the housing 7. Therefore, the outer diameter of the piston 10 and the inner diameter of the housing 7 are almost the same size. It has become. Further, a cylindrical valve body 12 is integrally formed on a side surface (hereinafter referred to as a surface 11) of the piston 10 on the output port 6 side. The valve body 12 is configured to contact the valve seat 9 described above to close the output port 6 and has a hemispherical tip. Further, the piston 10 is formed with a through hole 13 penetrating in the axial direction. Specifically, an orifice 13 communicating with both the front and back surfaces of the piston 10 is formed. The input port 5 described above is formed at a position that opens in a space closed by the piston 10 and the output port 6 when the valve body 12 contacts the valve seat 9.

  Further, a coil spring 14 that presses the surface 11 of the piston 10 in a direction away from the output port 9 is provided. That is, the coil spring 14 is sandwiched and accommodated between the surface 11 of the piston 10 and the inner surface of the lid 8, and is always configured to apply a load in a direction separating the piston 10 from the output port 6. Yes.

  Therefore, the load based on the hydraulic pressure (hereinafter referred to as line pressure) supplied from the hydraulic power source 2 is applied to the back surface 15 of the piston 10 described above, that is, the surface 15 opposite to the surface 11 to which the valve body 12 is connected. More specifically, a load obtained by integrating the area of the back surface 15 of the piston 10 acts on the line pressure, and the line pressure is integrated on the surface 11 of the piston 10 excluding the portion where the valve body 12 is provided. Based on the load and the elastic force of the coil spring 14 and the hydraulic pressure of the hydraulic actuator 3, the load received by the valve body 12 is configured to act.

  Further, in the electromagnetic valve 1 shown in FIG. 1, a through hole 16 is formed in the bottom portion 7 a of the housing 7, and a bypass port 17 is formed through the through hole 16. Specifically, a bypass port 17 communicating with the hydraulic actuator 3 is formed on the output side of the through hole 16 formed in the bottom portion 7a, that is, on the side opposite to the direction in which the piston 10 is provided. Therefore, the hydraulic pressure output from the back surface 15 of the piston 10 through the through hole 16 and the bypass port 17 is supplied to the hydraulic actuator 3.

  Moreover, the opening part of the output side in the through-hole 16 is formed in the taper shape, and the pilot valve 18 is provided so that the taper surface may be contact | connected. The pilot valve 18 includes a tip portion 18a having a hemispherical tip so as to contact the tapered surface, and an iron core 18b formed so that an electromagnetic force generated by energizing a solenoid 19 to be described later acts. It is configured. And the spring 20 which presses the edge part of the iron core 18b in the direction in which the front-end | tip part 18a approaches a taper surface is provided, and the solenoid 19 which applies electromagnetic force to the iron core 18b is arrange | positioned so that the outer peripheral side of the iron core 18b may be enclosed. ing. That is, the pilot valve 18 is configured to be attracted by applying an electromagnetic force generated by the solenoid 19 and the elastic force of the spring 20 is applied in a direction opposite to the attracting force.

  Here, the operation of the electromagnetic valve 1 configured as described above will be described. FIG. 1 shows a state where the output port 6 and the through hole 16 are closed. That is, the solenoid 19 is not energized. In this state, the load based on the line pressure, the elastic force of the coil spring 14, and the load that the valve body 12 receives based on the hydraulic pressure of the hydraulic actuator 3 act on the surface 11 of the piston 10. Further, since the line pressure is supplied to the back surface 15 side of the piston 10 through the orifice 13, a load based on the line pressure acts. It should be noted that the area that receives the load based on the line pressure is larger on the back surface 15 than the surface 11 of the piston 10, and the hydraulic pressure of the hydraulic actuator 3 is controlled using the line pressure as a source pressure. Low. Therefore, even when an elastic force is applied to the surface 12 of the piston 10, in a state where the through hole 16 is closed by the pilot valve 18 by determining the elastic force so as to be equal to or less than the load on the back surface 15 of the piston 10. The valve body 12 is pressed against the output port 6.

  In the state shown in FIG. 1, since the output port 6 and the through hole 16 are closed, the hydraulic pressure supplied from the hydraulic source 2 to the electromagnetic valve 1 is confined, and the hydraulic pressure of the hydraulic actuator 3 hardly increases or decreases. Therefore, the gear ratio and torque capacity in the belt type continuously variable transmission do not change.

  On the other hand, when the solenoid 19 is energized from the state shown in FIG. 1 and the suction force by the electromagnetic force becomes larger than the load that the pilot valve 18 is pressed by the spring 20, the pilot valve 18 is separated from the tapered surface in the through hole 16. The oil pressure supplied to the back surface 15 side of the piston 10 is supplied to the hydraulic actuator 3 via the bypass port 17, and the oil pressure of the back surface 15 of the piston 10 is reduced. Therefore, the balance of the load acting on the piston 10 is lost, the piston 10 moves in a direction in which the valve body 12 is separated from the output port 6, and as a result, the output port 6 is opened. Therefore, the line pressure is supplied to the hydraulic actuator 3 via the output port 6 and the oil supplied to the hydraulic actuator 3 is increased.

  As described above, when the solenoid 19 is energized, the pilot valve 18 is separated from the tapered surface of the through hole 16 and the line pressure is supplied to the hydraulic actuator 3, so that the hydraulic pressure of the hydraulic actuator 3 can be reduced at an early stage from the start of control. Can be increased. That is, the responsiveness of hydraulic control can be improved. Further, since the output port 6 is then opened and the line pressure is supplied to the hydraulic actuator 3, the hydraulic pressure can be supplied to the hydraulic actuator 3 via the bypass port 17 and the output port 6. Therefore, the substantial opening area for outputting the hydraulic pressure from the electromagnetic valve 1 can be increased, and the time for increasing the pressure of the hydraulic actuator 3 can be shortened.

  Next, a control example of the hydraulic control device using the above-described electromagnetic valve 1 will be described. When the above-described electromagnetic valve 1 is mounted on a vehicle, oil leaks not a little from an oil passage communicating with the electromagnetic valve 1 from the hydraulic power source 2 or the hydraulic actuator 3, so that the vehicle is stopped for a long period of time. The hydraulic pressure inside the electromagnetic valve 1 is reduced. Therefore, at the time of starting the hydraulic control device using the solenoid valve 1, in other words, at the time when the line pressure is not supplied to the solenoid valve 1, the ratio of the elastic force to the load acting on the valve body 12 increases and the valve body. 12 is separated from the output port 6, and the hydraulic source 2 and the hydraulic actuator 3 are in communication with each other via the electromagnetic valve 1.

  When the vehicle has been stopped for a long period of time, there is a possibility that oil has leaked from the hydraulic actuator 3 as described above. Therefore, it is preferable to increase the hydraulic pressure of the hydraulic actuator 3 at an early stage. That is, it is preferable to increase the hydraulic pressure of the hydraulic actuator 3 so that the belt and the pulley do not slip when the driving torque is transmitted. In addition, by accumulating the line pressure in the electromagnetic valve 1, high hydraulic pressure can be supplied to the hydraulic actuator 3 when the hydraulic actuator 3 is requested to increase pressure. It is preferable to increase the hydraulic pressure applied, that is, the hydraulic pressure supplied to both the front and back sides of the piston 10 in the electromagnetic valve 1. Furthermore, by closing the solenoid valve 1 at an early stage, the oil consumption can be reduced by shortening the start time of the hydraulic control device, that is, the control mode for enabling the hydraulic pressure of the hydraulic actuator 3 to be controlled. Therefore, it is preferable to increase the hydraulic pressure of the solenoid valve 1 at an early stage.

  A control example for quickly increasing the hydraulic pressure of the hydraulic actuator 3 and the electromagnetic valve 1 is shown in FIG. The control example shown in FIG. 2 shows control from the time when the hydraulic control device is activated. First, the set pressure of the regulator valve for adjusting the above-described line pressure is set to the maximum pressure (step S1). Specifically, the signal pressure supplied to the regulator valve is set high. Next, the other valves are closed and the operation of oil is prohibited (step S2). The control in step S2 is a control for supplying all the hydraulic pressure output from the hydraulic power source 2 to the solenoid valve 1. The other valves are hydraulic pressures such as clutches and brakes (not shown). It is a valve to control. And the rotation speed of the oil pump which is the hydraulic power source 2 is made into the high rotation speed for starting (step S3). FIG. 2 shows an example of control when an electric oil pump is used, and is configured to control the rotation speed of the electric oil pump. For example, even in the case of a mechanical oil pump, the power source and oil You may control the rotation speed of a mechanical oil pump by providing a transmission between pumps.

  By executing the control from step S1 to step S3 described above, the hydraulic pressure discharged from the hydraulic pressure source 2 is supplied to the hydraulic actuator 3 via the electromagnetic valve 1. Further, by controlling so that all the hydraulic pressure discharged from the hydraulic source 8 is supplied to the solenoid valve 1, the pressure loss in the oil passage communicating with the solenoid valve 1 and the hydraulic actuator 3 or in the solenoid valve 1 increases. Therefore, the hydraulic pressure in the electromagnetic valve 1 becomes equal to or higher than the hydraulic pressure of the hydraulic actuator 3. When the internal hydraulic pressure of the electromagnetic valve 1 becomes equal to or higher than a predetermined hydraulic pressure, the load acting on the back surface 15 of the piston 10 becomes greater than or equal to the load acting on the surface 11, and the valve body 12 closes the output port 6. That is, by supplying the hydraulic pressure output from the hydraulic pressure source 2 at a level higher than the hydraulic pressure at which the valve body 12 can close the output port 6, the hydraulic pressure of the electromagnetic valve 1 increases and the output port 6 is closed. The elastic coefficient of the coil spring 14 is determined so that the output port 6 is closed when the hydraulic pressure of the electromagnetic valve 1 becomes equal to or higher than a predetermined hydraulic pressure. Therefore, in step S4, it is determined whether or not the valve body 12 has closed the output port 6 (step S4). The determination in step S4 is performed by, for example, providing a hydraulic pressure sensor in an oil passage communicating with the solenoid valve 1 and the hydraulic actuator 3, the hydraulic pressure sensor is equal to or higher than a predetermined hydraulic pressure, and the change rate of the hydraulic pressure is equal to or lower than the predetermined change rate. It is possible to detect whether the valve body 12 has closed the output port 6 by providing a sensor for detecting contact between the valve body 12 and the output port 6.

  If a negative determination is made in step S4, the process returns to step S1 in order to continuously increase the hydraulic pressure of the hydraulic actuator 3 and the electromagnetic valve 1. On the other hand, if a positive determination is made in step S4, the set pressure of the regulator valve is set to the normal pressure (step S5), and the operation of other valves is permitted (step S6), and then the oil pump Is set to a normal value (step S7). The control from step S5 to step S7 is essentially for shifting to the normal control mode, and returning the set pressure of the regulator valve and the rotational speed of the oil pump to normal means that the vehicle travels. Sometimes it is necessary to change to the required hydraulic pressure or rotational speed.

  In the control example described above, the hydraulic pressure of the hydraulic actuator 3 and the electromagnetic valve 1 can be increased quickly. Therefore, it is possible to shorten the time from when the hydraulic control device is started to when normal control is performed. In addition, by making the hydraulic pressure of the solenoid valve 1 higher than the hydraulic pressure of the hydraulic actuator 3, a high hydraulic pressure can be supplied when there is a request to increase the hydraulic pressure of the hydraulic actuator 3. Can be improved. Furthermore, since the increase in the hydraulic pressure of the solenoid valve 1 is promoted by the pressure loss, the time until the solenoid valve 1 is closed can be shortened. can do.

  The hydraulic control device according to the present invention is not limited to the configuration of the electromagnetic valve 1 described above. That is, in the electromagnetic valve 1 described above, an example in which the coil spring 14 is disposed on the output port 6 side of the piston 10 has been shown, but the point is that the valve body 12 only needs to be able to apply a load in a direction away from the output port 6. Therefore, the coil spring 14 may be provided between the back surface 15 of the piston 10 and the bottom 7 a of the housing 7 so as to draw the piston 10 toward the bottom 7 a of the housing 7. In the above-described example, the pilot valve 18 is configured to be moved by the solenoid 19. However, the pilot valve 18 is configured to be moved by a motor and a feed screw mechanism as long as the opening / closing of the pilot valve 18 can be controlled. It may be a valve. That is, the poppet valve that can be the target of the hydraulic control device according to the present invention is not limited to a solenoid valve. Furthermore, although the through-hole 13 is formed in the piston 10 in the electromagnetic valve 1 described above, the hydraulic pressure acting on both the front and back surfaces of the piston 10 can be communicated, and the hydraulic pressure on the back side of the piston 10 is reduced. Sometimes, it is only necessary to provide a throttle so that a hydraulic pressure difference is temporarily generated. The hydraulic control target is not limited to the hydraulic actuator 3 attached to the belt-type continuously variable transmission, but may be a hydraulic actuator provided in a toroidal-type continuously variable transmission, a clutch, a brake, or the like.

  DESCRIPTION OF SYMBOLS 1 ... Solenoid valve, 2 ... Hydraulic source, 3 ... Hydraulic actuator, 5 ... Input port, 6 ... Output port, 10 ... Piston, 12 ... Valve body, 13 ... Orifice, 14 ... Coil spring, 18 ... Pilot valve, 19 ... Solenoid, 20 ... spring.

Claims (4)

An output port that outputs the hydraulic pressure supplied from the hydraulic source to the hydraulic control target unit, a valve body that contacts the output port and closes the output port, and a hydraulic pressure that acts on both the front and back sides together with the valve body An input port formed in communication with the hydraulic pressure source so that a hydraulic pressure supplied from the hydraulic pressure source acts on a piston that moves in accordance with the pressure difference and a surface of the piston on which the valve body is provided In a hydraulic control device having an on-off valve having
An elastic member for applying an elastic force to the piston in a direction in which the valve body is separated from the output port;
A communicating portion having a throttle for communicating hydraulic pressure acting on both sides of the piston;
A hydraulic control device comprising: a pressure reducing mechanism that selectively reduces the hydraulic pressure acting on a back surface of the piston opposite to a surface on which the valve body is provided.   When the hydraulic pressure is started to be supplied to the on-off valve, the hydraulic pressure supplied from the hydraulic source to the on-off valve is temporarily increased beyond the hydraulic pressure at which the piston can keep the output port closed. The hydraulic control device according to claim 1.   The hydraulic control apparatus according to claim 1, wherein the hydraulic pressure discharged from the pressure reducing mechanism is configured to be supplied to the hydraulic pressure control target unit.   The pressure reducing mechanism opens and closes the discharge unit by applying an electromagnetic force to the pilot valve by energizing a discharge unit that discharges the hydraulic pressure supplied to the back side of the piston, and a pilot valve that closes the discharge unit. The hydraulic control device according to claim 1, further comprising a solenoid to be operated.

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