JP2006170397A - Hydraulic clutch control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic clutch control valve having two-stage pressure property that pressure quickly rises up to preset one at the beginning of connecting a hydraulic clutch and the pressure more gently rises at the ending of connecting the hydraulic clutch than at the beginning. <P>SOLUTION: The hydraulic clutch control valve 6 comprises a valve body 11, a piston 21, and a spring assembly 31 to be compressed between the piston 21 and a spring supporting face 11c of the valve body 11 by the thrusting load of the piston 21. The spring assembly 31 has a first spring 32 thrust and compressed to the side of the spring supporting face 11c by the piston 21 and a second spring 33 arranged between the first spring 32 and the spring supporting face 11c, on which the thrusting load of the piston 21 operates via the first spring 32. The second spring 33 is compressed when the thrusting load of the piston 21 operating thereon via the first spring 32 exceeds a preset value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydraulic clutch control valve, and more particularly to a hydraulic clutch control valve that is provided in a hydraulic circuit for supplying hydraulic oil to the hydraulic clutch and gradually increases the pressure of the hydraulic oil supplied to the hydraulic clutch.

  Some transmissions for construction machinery and industrial machinery use a hydraulic clutch to move forward and backward. The hydraulic oil used for controlling such a hydraulic clutch includes an oil pump, a main pressure adjusting valve provided on the discharge side of the oil pump, a direction switching valve that controls supply and discharge of hydraulic oil to the hydraulic clutch, and a hydraulic clutch Is supplied from a hydraulic circuit connected to a hydraulic clutch control valve for gradually increasing the pressure of the hydraulic oil supplied to the engine (see, for example, Patent Document 1).

  A hydraulic clutch control valve that gradually increases the pressure of hydraulic oil supplied to the hydraulic clutch mainly includes a valve body, a piston, and a spring. The valve body has a hollow space communicating with the hydraulic circuit. The piston divides this space into a piston chamber that communicates with the hydraulic circuit and a spring chamber that does not communicate with the hydraulic circuit, and is movably provided in this space. The spring is disposed between the piston and the spring receiving surface of the valve body facing the piston. When the piston moves toward the spring receiving surface by supplying hydraulic oil into the piston chamber, the spring is pressed. The load is compressed between the piston and the spring receiving surface.

When the circuit is formed so that the hydraulic oil can be supplied to the hydraulic clutch by switching the direction switching valve or the like, the hydraulic oil boosted by the oil pump flows into the piston chamber of the hydraulic clutch control valve. The piston moves to the spring receiving surface side. At this time, since the pressing load of the piston acts on the spring, the spring is compressed between the piston and the spring receiving surface by the pressing load. As a result, the piston moves toward the spring receiving surface while being controlled by the spring force of the spring, and the pressure of the hydraulic oil in the piston chamber gradually increases. Accordingly, the pressure of the hydraulic oil supplied to the hydraulic clutch is gradually increased. Thus, the hydraulic clutch is connected.
Japanese Patent Laid-Open No. 2002-235846

  By using the conventional hydraulic clutch control valve, it is possible to reduce the shock when the hydraulic clutch is engaged, but the response time until the hydraulic clutch is engaged after the supply of hydraulic oil is started. It tends to be longer. Further, since the hydraulic clutch is configured to be connected by engagement between a plurality of friction plates that rotate relative to each other, for example, the load that starts the engagement between the friction plates is quickly applied, and this load is applied. It is desirable to continue the application until the engagement between the friction plates is completed. For this reason, the pressure characteristics of the hydraulic oil supplied to the hydraulic clutch include a predetermined pressure (specifically, the pressure of the hydraulic oil corresponding to the load at which engagement between the friction plates starts to be started) at the initial connection of the hydraulic clutch. It is desirable to have a two-stage pressure characteristic in which the pressure rises quickly until the end of the engagement of the hydraulic clutch, and the pressure rises more slowly than the beginning of the connection.

  In order to obtain such a two-stage pressure characteristic, a configuration such as providing a timing valve is conceivable. However, there arises a problem that the configuration becomes complicated.

  It is an object of the present invention to control a hydraulic clutch that enables a two-stage pressure characteristic in which the hydraulic clutch quickly rises to a predetermined pressure at the initial stage of engagement and the pressure gradually rises at the end of the hydraulic clutch. To provide a valve.

  The hydraulic clutch control valve according to claim 1 is provided in a hydraulic circuit for supplying hydraulic oil to the hydraulic clutch, and is a hydraulic clutch control valve that gradually increases the pressure of the hydraulic oil supplied to the hydraulic clutch. A valve body, a piston, and a spring assembly are provided. The valve body has a hollow space communicating with the hydraulic circuit. The piston is divided into a piston chamber that communicates with the hydraulic circuit and a spring chamber that does not communicate with the hydraulic circuit, and is movably provided in the space. The spring assembly is disposed in the spring chamber between the piston and the spring receiving surface of the valve body facing the piston, and when the piston moves toward the spring receiving surface by supplying hydraulic oil into the piston chamber. Furthermore, the piston is compressed between the piston and the spring receiving surface by the pressing load from the piston. The spring assembly includes a first spring and a second spring. The first spring is pressed and compressed by the piston toward the spring receiving surface. The second spring is disposed between the first spring and the spring receiving surface so that the pressing load from the piston acts via the first spring. The second spring is provided after the first spring starts to be compressed by the pressing load from the piston, and is compressed when the pressing load acting from the piston via the first spring exceeds a predetermined value. It has been.

  In this hydraulic clutch control valve, since the pressure load acting on the first spring from the piston is small when the piston moves to the spring receiving surface side by the hydraulic oil flowing into the piston chamber at the initial connection of the hydraulic clutch, The spring functions as a rigid body and only the first spring is compressed. That is, the pressure of the hydraulic oil in the piston chamber gradually increases while being controlled by the spring force of the first spring constituting the spring assembly. Next, when the pressure of the hydraulic oil in the piston chamber rises and the pressing load acting on the first spring from the piston exceeds a predetermined value, the second spring also functions as an elastic body. Both the first spring and the second spring are compressed. That is, the pressure of the hydraulic oil in the piston chamber gradually increases while being controlled by the spring force when the first spring and the second spring constituting the spring assembly are connected in series (hereinafter referred to as the end of the connection of the hydraulic clutch). To do).

  Here, the spring force of the spring assembly at the initial connection of the hydraulic clutch is determined only by the spring constant of the first spring, and the spring force of the spring assembly at the end of the connection of the hydraulic clutch is the first spring and the second spring. The spring constant when two springs are connected in series is the reciprocal of the reciprocal sum of the spring constants of the two springs, and is smaller than the spring constant of each spring. In particular, the rising speed of the hydraulic oil pressure in the piston chamber at the end of the engagement of the hydraulic clutch is smaller than the rising speed of the hydraulic oil pressure in the piston chamber at the initial connection of the hydraulic clutch.

  In this way, this hydraulic clutch control valve has a simple structure consisting of a single piston, and the hydraulic clutch quickly rises to a predetermined pressure at the beginning of the coupling, and the hydraulic clutch is more slowly at the end of the coupling than at the beginning of the coupling. Can be obtained.

  The hydraulic clutch control valve according to claim 2 is provided in a hydraulic circuit for supplying hydraulic oil to the hydraulic clutch, and is a hydraulic clutch control valve that gradually increases the pressure of the hydraulic oil supplied to the hydraulic clutch. A valve body, a piston, and a spring assembly are provided. The valve body has a hollow space communicating with the hydraulic circuit. The piston divides the space into a piston chamber that communicates with the hydraulic circuit and a spring chamber that does not communicate with the hydraulic circuit, and is provided movably in the space. The spring assembly is disposed in the spring chamber between the piston and the spring receiving surface of the valve body facing the piston, and when the piston moves toward the spring receiving surface by supplying hydraulic oil into the piston chamber. Furthermore, the piston is compressed between the piston and the spring receiving surface by the pressing load from the piston. The spring assembly includes a first spring, a second spring, and an intermediate member. The first spring is pressed and compressed by the piston toward the spring receiving surface. The second spring is disposed between the first spring and the spring receiving surface so that a pressing load from the piston acts via the first spring. The intermediate member is interposed between the first spring and the second spring, and is movable to the spring receiving surface side and restricted to move to the piston side.

  In this hydraulic clutch control valve, an intermediate member that is movable toward the spring receiving surface and restricted to move toward the piston is interposed between the first spring and the second spring. Even when is not applied to the first spring, the second spring can be provided so as to be shorter than its free length. For this reason, the 2nd spring can be made into the state where the load according to the displacement from the free length was always accumulated irrespective of the state of the 1st spring. As a result, the second spring is compressed when the pressing load acting on the first spring from the piston exceeds the load corresponding to the displacement from the free length (hereinafter referred to as a predetermined value).

  For this reason, in this hydraulic clutch control valve, the pressing load acting on the first spring from the piston is small when the piston moves to the spring receiving surface side by the hydraulic oil flowing into the piston chamber at the initial connection of the hydraulic clutch. The second spring functions as a rigid body, and only the first spring is compressed. That is, the pressure of the hydraulic oil in the piston chamber gradually increases while being controlled by the spring force of the first spring constituting the spring assembly. Next, when the pressure of the hydraulic oil in the piston chamber rises and the pressing load acting on the first spring from the piston exceeds a predetermined value, the second spring also functions as an elastic body. Both the first spring and the second spring are compressed. That is, the pressure of the hydraulic oil in the piston chamber gradually increases while being controlled by the spring force when the first spring and the second spring constituting the spring assembly are connected in series (hereinafter referred to as the end of the connection of the hydraulic clutch). To do).

  Here, the spring force of the spring assembly at the initial connection of the hydraulic clutch is determined only by the spring constant of the first spring, and the spring force of the spring assembly at the end of the connection of the hydraulic clutch is the first spring and the second spring. The spring constant when two springs are connected in series is the reciprocal of the reciprocal sum of the spring constants of the two springs, and is smaller than the spring constant of each spring. In particular, the rising speed of the hydraulic oil pressure in the piston chamber at the end of the engagement of the hydraulic clutch is smaller than the rising speed of the hydraulic oil pressure in the piston chamber at the initial connection of the hydraulic clutch.

  In this way, this hydraulic clutch control valve has a simple structure consisting of a single piston, and the hydraulic clutch quickly rises to a predetermined pressure at the beginning of the coupling, and the hydraulic clutch is more slowly at the end of the coupling than at the beginning of the coupling. Can be obtained.

  The hydraulic clutch control valve according to the present invention has a simple structure consisting of a single piston, and the hydraulic clutch quickly rises to a predetermined pressure at the initial stage of coupling, and the hydraulic clutch has a gentler pressure at the end of coupling than at the initial stage of coupling. Ascending two-stage pressure characteristics can be obtained.

  Hereinafter, an embodiment of a hydraulic circuit including a hydraulic clutch control valve according to the present invention will be described based on the drawings.

(1) Schematic Configuration of Hydraulic Circuit FIG. 1 is a schematic configuration diagram of a hydraulic circuit 1 including a hydraulic clutch control valve 6 according to the present invention.

  The hydraulic circuit 1 is a hydraulic circuit for supplying hydraulic oil to the hydraulic clutch 7. The hydraulic circuit 1 mainly includes an oil tank 2, an oil pump 3, a main pressure adjustment valve 4, an orifice 5, and a hydraulic clutch control valve 6. And are connected.

  The oil tank 2 is a container for storing hydraulic oil. The oil pump 3 has a suction port connected to the oil tank 2, and is a device that sucks in the hydraulic oil accumulated in the oil tank 2, boosts it, and discharges it. The main pressure adjustment valve 4 is connected to the discharge side of the oil pump 3 and is a valve mechanism that adjusts the pressure of the hydraulic oil that has been boosted and discharged by the oil pump 3. The orifice 5 is a mechanism that throttles the flow path of the hydraulic oil whose pressure is adjusted by the main pressure adjustment valve 4 and depressurizes the pressure of the hydraulic oil that passes therethrough. The hydraulic clutch 7 is connected so that hydraulic oil after being throttled by the orifice 5 is supplied. The hydraulic clutch control valve 6 is connected to an oil passage 8 between the orifice 5 and the hydraulic clutch 7, and is a valve mechanism that gradually increases the pressure of hydraulic oil supplied to the hydraulic clutch 7. When a plurality of hydraulic clutches 7 are provided, a hydraulic circuit in which a direction switching valve for controlling supply and discharge of hydraulic oil to and from the hydraulic clutch 7 is provided between the hydraulic clutch control valve 6 and the hydraulic clutch 7 is provided. Adopted.

(2) Structure of Hydraulic Clutch Control Valve The hydraulic clutch control valve 6 mainly includes a valve main body 11, a piston 21, and a spring assembly 31.

  The valve body 11 has a hollow space S that communicates with the oil passage 8. The space S is an elongated columnar space in the present embodiment. The valve body 11 is provided with a communication hole 11a that communicates the space S with the oil passage 8 at one end in the longitudinal direction, and a drain hole 11b that communicates with the space S near the center in the longitudinal direction. Further, the end in the longitudinal direction (that is, the other end in the longitudinal direction) of the space S where the communication hole 11 a of the valve body 11 is not provided is closed, and the other end in the longitudinal direction of the valve body 11 is closed with a spring assembly. A spring receiving surface 11c that receives the three-dimensional body 31 is provided. Furthermore, an annular groove 11 d is formed on the inner surface of the valve body 11 near the center in the longitudinal direction. In the present embodiment, the valve main body 11 includes a first main body portion 12 that forms a portion from one end in the longitudinal direction including the communication hole 11a and the drain hole 11b to the vicinity of the center in the longitudinal direction, a spring receiving surface 11c, and a groove portion 11d. It has a structure that can be divided into a second main body portion 13 that forms a portion from the vicinity of the center in the longitudinal direction to the other end in the longitudinal direction.

  The piston 21 does not communicate with the hydraulic circuit 1 with the piston chamber S1 that communicates the space S with the oil passage 8 of the hydraulic circuit 1 (that is, one end side in the longitudinal direction of the valve body 11). It is divided into a spring chamber S2 on the other end side, and is provided in the space S so as to be movable in the longitudinal direction of the valve body 11. For this reason, when the piston 21 moves in the space S toward the spring receiving surface 11c, the volume of the piston chamber S1 increases and the volume of the spring chamber S2 decreases, and the piston 21 moves in the space S to the anti-spring receiving surface 11c side. Is moved, the volume of the piston chamber S1 is decreased and the volume of the spring chamber S2 is increased. In the present embodiment, the piston 21 has a flat plate portion 21a facing one end in the longitudinal direction of the valve body 11, and a cylindrical portion 21b extending from the outer peripheral end of the flat plate portion 21a toward the spring receiving surface 11c. On the spring receiving surface 11c side of the flat plate portion 21a, an end portion on the side opposite to the spring receiving surface 11c of the spring assembly 31 is received, and a pressing surface 21c that presses the spring assembly 31 toward the spring receiving surface 11c is formed. ing. The outer peripheral surface of the cylindrical portion 21b is in sliding contact with the inner surface of the valve body 11, and when the pressure of the hydraulic oil in the piston chamber S1 rises, the hydraulic oil leaks from the piston chamber S1 to the spring chamber S2. Sealed so that there is no.

  The spring assembly 31 is disposed in the spring chamber S2 between the piston 21 (specifically, the pressing surface 21c) and the spring receiving surface 11c facing the piston 21, and operates in the piston chamber S1. When the piston 21 moves toward the spring receiving surface 11c by the supply of oil, the piston 21 is compressed between the piston 21 and the spring receiving surface 11c by the pressing load from the piston 21, and mainly the first spring 32. And a second spring 33. In the present embodiment, the first spring 32 and the second spring 33 are coil springs. In addition, the coil outer diameter of the first spring 32 is slightly smaller than the coil outer diameter of the second spring 33 in the present embodiment. One end of the first spring 32 is in contact with the pressing surface 21 c of the piston 21. The second spring 33 is disposed between the end of the first spring 32 on the spring receiving surface 11c side (that is, the other end of the first spring 32) and the spring receiving surface 11c.

  In addition, a washer 34 as an intermediate member is interposed between the other end of the first spring 32 and an end of the second spring 33 on the first spring 31 side (hereinafter referred to as one end of the second spring 32). ing. The washer 34 is an annular member whose surface on the piston 21 side abuts on the other end of the first spring 31 and whose surface on the spring receiving surface 11 c side abuts on one end of the second spring 32. In the present embodiment, the outer diameter of the washer 34 is substantially the same as the outer diameter of the coil of the second spring 32, and a slight gap exists between the inner surface of the space S. Further, the inner diameter of the washer 34 is substantially the same as the inner diameter of the coil of the first spring 31.

  A cylindrical stop pin 36 is provided in the coils of the first spring 32 and the second spring 33. When the first spring 32 and the second spring 33 are compressed between the pressing surface 21c of the piston 21 and the spring receiving surface 11c, both ends in the longitudinal direction of the stop pin 36 are the pressing surface 21c and the spring receiving surface 11c. It is a member which contacts. The length of the stop pin 36 is the displacement when the first spring 32 and the second spring 33 are compressed (in other words, the distance L2 between the piston 21 and the spring receiving surface 11c in FIG. 4) and the connection of the hydraulic clutch 7. It is set in consideration of the pressure of the hydraulic oil that is sometimes required (that is, the load acting on the first spring 32 and the second spring 33 from the piston 21).

  As described above, the spring assembly 31 is basically pressed by the pressing load from the piston 21 and pressed to the spring receiving surface 11c side to be compressed, and the pressing load from the piston 21. Are provided in series via the first spring 32, a washer 34 interposed between the first spring 32 and the second spring 33, the first spring 32 and the second spring 32. It is comprised from the column-shaped stop pin 36 provided in the coil of the spring 33. As shown in FIG.

  Further, a snap ring 35 is fitted in the groove 11 d of the valve body 11. The snap ring 35 is an annular member whose surface on the spring receiving surface 11c side comes into contact with the surface on the piston 21 side of the washer 34, and restricts the movement of the washer 34 toward the piston 21 side when fitted in the groove 11d. It functions as a locking part. The inner diameter of the snap ring 35 is smaller than the outer diameter of the first spring 32 so that it does not interfere with the outer periphery of the first spring 32.

  Here, even when the second spring 33 is arranged so that the second spring 33 is shorter than the free length even when the pressing load from the piston 21 is not applied to the first spring 32, Since the movement of the end of the second spring 33 on the piston 21 side to the piston 21 side is limited by the snap ring 35 fitted in the groove 11d, the second spring 33 is not dependent on the state of the first spring 32, A load corresponding to the displacement from the free length (hereinafter referred to as a predetermined value) is always set to be accumulated. Thus, even if the second spring 33 starts to apply a pressing load from the piston 21 to the first spring 32 due to the hydraulic oil flowing into the piston chamber S <b> 1, the pressing load acting on the first spring 32 from the piston 21 is not applied. It is not compressed until it exceeds a predetermined value (see the load F1 in FIG. 5), and when it exceeds the predetermined value, it can be compressed together with the first spring 32.

(3) Operation of Hydraulic Clutch Control Valve when Hydraulic Clutch is Connected Next, the operation of the hydraulic clutch control valve 6 when the hydraulic clutch 7 is connected will be described with reference to FIGS. 2 to 4 are views showing the operation of the hydraulic clutch control valve 6 when the hydraulic clutch 7 is connected. FIG. 5 is a graph showing the pressure characteristics of the hydraulic oil in the piston chamber S1 of the hydraulic clutch control valve 6 and the load characteristics of the first spring 32 and the second spring 33 when the hydraulic clutch 7 is connected.

  First, before the hydraulic clutch 7 is connected, as shown in FIG. 2, the piston chamber S1 has the smallest volume due to the spring force of the first spring 32 and the second spring 33, that is, the piston 21 is The valve body 11 is located at a position L0 away from the spring receiving surface 11c. At this time, the pressure of the hydraulic oil in the piston chamber S1 is the pressure P0. The coil length of the first spring 32 is A0. The load applied from the piston 21 to the first spring 32 is the load F0. The end of the second spring on the piston 21 side is set to a length B0 shorter than the free length by a snap ring 35 fitted in the groove 11d, and a load corresponding to the displacement from the free length is set. The corresponding load F1 is accumulated.

  In this state, when the hydraulic oil boosted by the oil pump 3 flows into the piston chamber S1 of the hydraulic clutch control valve 6, the piston 21 moves toward the spring receiving surface 11c. At this time, since the pressing load of the piston 21 acts on the spring assembly 31, the spring assembly 31 is compressed between the pressing surface 21c of the piston 21 and the spring receiving surface 11c by the pressing load. Here, since the load F1 is accumulated in the second spring 33, in the range where the pressing load from the piston 21 is smaller than the load F1, the second spring 33 that has already accumulated the load F1 functions as a rigid body, The second spring 33 is not compressed, and only the first spring 32 is compressed between the pressing surface 21 c and the washer 34. As a result, the piston 21 moves to the spring receiving surface 11c side while being controlled by the spring force of the first spring 32, and gradually increases to the pressure P1 of the hydraulic oil in the piston chamber S1. The pressure of the supplied hydraulic oil is also gradually increased. Then, as shown in FIG. 3, the first spring 32 is compressed to the length A <b> 1 by increasing the pressing load applied from the piston 21 to the first spring 32 from the load F <b> 0 to the load F <b> 1. This process (hereinafter referred to as an initial connection process of the hydraulic clutch 7) is performed between time T0 and time T1.

  Next, when the pressing load from the piston 21 exceeds the load F1, the second spring 33 also functions as an elastic body, and both the first spring 32 and the second spring 33 are compressed by the pressing load from the piston 21. It will be. As a result, the piston 21 moves toward the spring receiving surface 11c and gradually increases to the pressure P2 of the hydraulic oil in the piston chamber S1 while being controlled by the spring force when the first spring 32 and the second spring 33 are connected in series. Therefore, according to this, the pressure of the hydraulic oil supplied to the hydraulic clutch 7 is also gradually increased. As shown in FIG. 4, the first spring 32 and the second spring 33 increase the pressing load acting on the first spring 32 from the piston 21 from the load F1 to the load F2, respectively. Will be compressed to B2. This process (hereinafter referred to as a connection end process of the hydraulic clutch 7) is performed between time T1 and time T2.

  Further, when a pressing load is applied to the first spring 32 and the second spring 33 from the piston 21, the pressing surface 21 c of the piston 21 comes into contact with the stop pin 36, so that the control by the spring force of the first spring 32 and the second spring 33 is performed. Is raised to a pressure P3 near the discharge pressure of the oil pump 3.

  By such an operation of the hydraulic clutch control valve 6, the pressure of the hydraulic oil supplied to the hydraulic clutch 7 is gradually increased, and the hydraulic clutch 7 is connected.

(4) Features of the hydraulic clutch control valve The hydraulic clutch control valve 6 of this embodiment has the following features.

(A)
In the hydraulic clutch control valve 6 of the present embodiment, the washer 34 as an intermediate member that is movable toward the spring receiving surface 11 c and restricted to move toward the piston 21 is provided between the first spring 32 and the second spring 33. Therefore, even when the pressing load from the piston 21 is not applied to the first spring 32, the second spring 33 can be provided so as to be shorter than the free length. For this reason, regardless of the state of the first spring 32, the second spring 33 can be in a state in which a load corresponding to the displacement from the free length is always accumulated. Thereby, the second spring 33 is compressed when the pressing load acting on the first spring 32 from the piston 21 exceeds the load corresponding to the displacement from the free length (see the load F1 in FIG. 5). become.

  Here, the spring force of the spring assembly 31 at the initial connection of the hydraulic clutch 7 is determined only by the spring constant of the first spring 32, and the spring force of the spring assembly 31 at the end of the connection of the hydraulic clutch 7 is the first. The spring constant when the two springs 32 and 33 are connected in series is the reciprocal of the reciprocal sum of the spring constants of the two springs 32 and 33. As a result, the increase rate of the hydraulic oil pressure in the piston chamber S1 at the end of connection of the hydraulic clutch 7 results in the piston chamber S1 in the initial connection of the hydraulic clutch 7 being smaller than the spring constant of each spring 32, 33. It becomes smaller than the rate of increase in the pressure of the hydraulic oil inside (see FIG. 5).

  On the other hand, the conventional hydraulic clutch control valve that gradually increases the pressure of the hydraulic oil in the piston chamber by the spring force of one spring has a one-stage pressure characteristic indicated by a two-dot chain line in FIG. The pressure characteristics up to P1 are the same as those of the hydraulic clutch control valve 6 of this embodiment, but the pressure rise time (ie, T2-T1) from the pressure P1 to the pressure P2 is higher than the pressure rise time (ie, T2-T1). It can be seen that the pressure effective for connecting the hydraulic clutch cannot be continuously applied for a long time because T′−T1) is short.

  In this way, the hydraulic clutch control valve 6 has a simple structure consisting of one piston 21, and the initial connection of the hydraulic clutch 7 quickly rises to a predetermined pressure. The final connection of the hydraulic clutch 7 is earlier than the initial connection. A two-stage pressure characteristic in which the pressure gradually increases can be obtained.

(B)
In the hydraulic clutch control valve 6 of the present embodiment, the groove portion 11d and the snap ring 35 are used as a locking portion for freely moving the washer 34 to the spring receiving surface 11c side and restricting the movement to the piston 21 side. Therefore, the configuration is not complicated.

(5) Other Embodiments Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments and can be changed without departing from the gist of the invention. It is.

  For example, in the above-described embodiment, the groove portion 11d and the snap ring 35 are used as a locking portion for allowing the washer 34 to be movable to the spring receiving surface 11c side and restricting the movement to the piston 21 side. Instead, a protrusion may be provided on the valve body 11 to form a locking portion.

It is a schematic block diagram of the hydraulic circuit provided with the valve for hydraulic clutch control concerning this invention. It is a figure which shows operation | movement of the valve for hydraulic clutch control at the time of hydraulic clutch connection. It is a figure which shows operation | movement of the valve for hydraulic clutch control at the time of hydraulic clutch connection. It is a figure which shows operation | movement of the valve for hydraulic clutch control at the time of hydraulic clutch connection. It is a graph which shows the pressure characteristic of the hydraulic fluid of the piston chamber of the hydraulic clutch control valve at the time of a hydraulic clutch connection, and the load characteristic of a 1st spring and a 2nd spring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic circuit 6 Hydraulic clutch control valve 7 Hydraulic clutch 11 Valve body 11c Spring receiving surface 21 Piston 31 Spring assembly 32 First spring 33 Second spring 34 Washer (intermediate member)
S space S1 piston chamber S2 spring chamber

Claims (2)

A hydraulic clutch control valve that is provided in a hydraulic circuit for supplying hydraulic oil to the hydraulic clutch and gradually increases the pressure of the hydraulic oil supplied to the hydraulic clutch;
A valve body having a hollow space communicating with the hydraulic circuit;
Dividing the space into a piston chamber communicating with the hydraulic circuit and a spring chamber not communicating with the hydraulic circuit, and a piston movably provided in the space;
In the spring chamber, the piston is disposed between the piston and a spring receiving surface of the valve body facing the piston, and the piston moves toward the spring receiving surface by supplying hydraulic oil into the piston chamber. A spring assembly that is compressed between the piston and the spring receiving surface by a pressing load from the piston.
The spring assembly includes a first spring that is pressed and compressed by the piston toward the spring receiving surface, and the first spring and the spring so that a pressing load from the piston acts via the first spring. A second spring disposed between the spring receiving surface and
The second spring is compressed after the first spring starts to be compressed by the pressing load from the piston and the pressing load acting from the piston via the first spring exceeds a predetermined value. Provided to be,
Hydraulic clutch control valve. A hydraulic clutch control valve that is provided in a hydraulic circuit for supplying hydraulic oil to the hydraulic clutch and gradually increases the pressure of the hydraulic oil supplied to the hydraulic clutch;
A valve body having a hollow space communicating with the hydraulic circuit;
Dividing the space into a piston chamber communicating with the hydraulic circuit and a spring chamber not communicating with the hydraulic circuit, and a piston movably provided in the space;
In the spring chamber, the piston is disposed between the piston and a spring receiving surface of the valve body facing the piston, and the piston moves toward the spring receiving surface by supplying hydraulic oil into the piston chamber. A spring assembly that is compressed between the piston and the spring receiving surface by a pressing load from the piston.
The spring assembly includes a first spring that is pressed and compressed by the piston toward the spring receiving surface, and the first spring and the spring so that a pressing load from the piston acts via the first spring. The second spring disposed between the spring receiving surface and the first spring and the second spring are interposed between the second spring and the spring receiving surface, and the movement toward the piston is restricted. Intermediate member,
Hydraulic clutch control valve.

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