JP2013155798A - Stop valve having slow return function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stop valve having a slow return function, with simple structure and superior productivity.SOLUTION: A valve case 13 includes a first port 11, a second port 12, and a valve unit for closing communication between the fist and second ports 11, 12. The valve unit in contact with a first seat part 26 closes the communication between the first and second ports 11, 12. The valve unit includes a first valve body 21 and a second valve body 22. A first through-hole 35 is formed to penetrate through the first valve body 21. The first port 11 communicates with the second port 12 via the first through-hole 35. In the first through-hole 35, the second valve body 22 moves from the rear. A second seat part 27 is formed in the first valve body 21. The second valve body 22 is brought into abutment with the second seat part 27 to close the first through-hole 35, and the communication between the first and second ports 11, 12 is closed.

Description

  The present invention relates to a stop valve having a slow return function in which a stop valve and a slow return valve are integrally formed when a stop valve and a slow return valve are provided on a hydraulic circuit.

  Conventionally, on the hydraulic circuit, a stop valve that closes the flow path and a slow return valve that adjusts the flow rate of hydraulic fluid that passes through the valve by restricting the flow path have been installed separately. However, providing the two valves separately increases the number of parts, complicates the structure, and requires a large space for the hydraulic circuit.

  Therefore, as shown in Patent Document 1, a stop valve having a slow return function that combines a stop valve function and a slow return valve function has been proposed.

JP 2001-54302 A

  As shown in FIG. 10, the stop valve having a slow return function in Patent Document 1 is formed between a first port 111 connected to an actuator and a second port 112 connected to a pump and a tank. The stop valve having the slow return function includes a first seat portion 126 formed in the valve case 113, a columnar first valve body 121 in contact with the first seat portion 126, and a first along the center line. A through-hole 135 penetrating through the valve body 121, a second seat portion 127 formed in the first valve body, a second valve body 122 that comes into contact with the second seat portion 127 from the rear, and the like are provided. A stopper ST is provided in front of the first valve body 121, and a spring 123 is interposed between the stopper ST and the first valve body 121. The first valve body 121 is subjected to an elastic force in the direction of the second valve body 122 by the spring 123. A slow return throttle can be formed between the first valve body 121 and the first seat portion 126. In the stop valve having such a slow return function, groove portions G1, G2, and G3 are formed between the cylindrical body portion 101 and the conical head portion 102. The groove portions G1, G2, and G3 are for the hydraulic oil to pass when the hydraulic oil is sent from the second port 112 side to the first port side 111 with the slow return throttle closed. The hydraulic oil that has passed through the grooves G1, G2, and G3 flows to the first port 111 through the through hole 135.

  However, the stop valve having such a slow return function has a problem that the structure of the grooves G1, G2, G3 of the first valve body 121 is complicated and the productivity of the first valve body 121 is poor. Therefore, the present invention is to provide a stop valve having a slow return function with a simple structure and good productivity.

For this reason, the invention according to claim 1 includes a first port connected to the actuator,
A second port connected to the pump and the tank and in communication with the first port;
A valve case including a valve body unit capable of closing communication between the first port and the second port;
In the stop valve having a slow return function that closes the communication between the first port and the second port by contacting the front portion of the valve body unit with the first seat portion formed in the valve case,
The valve body unit is composed of a first valve body and a second valve body,
The first valve body is configured integrally with a cylindrical body portion and a head portion that comes into contact with the first seat portion,
Forming a first through hole so as to penetrate the first valve body along the center line of the body portion;
Enabling the first port and the second port to communicate with each other through the first through hole;
A stop valve having a slow return function that allows the second valve body to move from the rear in the first through hole,
A second seat portion is formed in the body portion of the first valve body, and the second valve body is configured integrally with a cylindrical body portion and a head portion that contacts the second seat portion,
By contacting the head of the second valve body with the second seat portion, the first through hole is closed and the communication between the first port and the second port is closed. .

  According to a second aspect of the present invention, in the stop valve having a slow return function according to the first aspect, an elastic member is provided between the first valve body and the second valve body, and the elastic member is the first valve body. The first valve body and the second valve body are contracted.

  According to a third aspect of the present invention, there is provided the stop valve having a slow return function according to the first or second aspect, wherein the valve body operating means is capable of moving the valve body unit in contact with a rear portion of the second valve body. Is provided in a valve case through a valve body operating means guide.

  According to a fourth aspect of the present invention, in the stop valve having a slow return function according to the third aspect, the second valve body and the valve body operating means are integrally formed.

  According to a fifth aspect of the present invention, in the stop valve having a slow return function according to the third or fourth aspect, an elastic member is provided between the first valve body and the valve body operating means guide, and the elastic member Is contracted by the first valve body and the valve body operating means guide.

  According to the first aspect of the present invention, the first port connected to the actuator, the second port connected to the pump and the tank and communicated with the first port, the first port, and the second port The valve case includes a valve body unit capable of closing communication, and the front portion of the valve body unit is in contact with a first seat portion formed in the valve case, so that the first port and the second port In the stop valve having a slow return function for closing the communication, the valve body unit is composed of a first valve body and a second valve body, and the first valve body includes a cylindrical body portion, and the first valve body. A head part that abuts on one seat part is formed integrally, a first through hole is formed so as to penetrate the first valve body along a center line of the body part, and the first through hole is formed. Via the first port and the second port A stop valve having a slow return function that allows communication and allows the second valve body to move from the rear in the first through hole, and the second seat portion is formed in the body portion of the first valve body The second valve body is formed integrally with a cylindrical body portion and a head portion that contacts the second seat portion, and the head portion of the second valve body is abutted against the second seat portion. By making contact, the first through hole is closed, and the communication between the first port and the second port is closed.

  Therefore, it is possible to provide a stop valve having a slow return function with a simple structure and good productivity.

  According to the second aspect of the present invention, an elastic member is provided between the first valve body and the second valve body, and the elastic member is contracted by the first valve body and the second valve body. Therefore, the followability of the first valve body to the first seat can be improved by the elastic force of the elastic member acting in the direction in which the first valve body is brought into contact with the first seat.

  According to the third aspect of the invention, the valve case is provided with the valve body operating means that contacts the rear portion of the second valve body and that allows the valve body unit to move through the valve body operating means guide. The size of the slow return throttle can be adjusted by the valve body operating means.

  According to the invention described in claim 4, since the second valve body and the valve body operating means are integrally formed, a stop valve having a slow return function with a simpler structure and good productivity is provided. be able to.

  According to the invention described in claim 5, an elastic member is provided between the first valve body and the valve body operating means guide, and the elastic member is formed by the first valve body and the valve body operating means guide. Since it is contracted, the followability of the first valve body to the first seat can be improved by the elastic force of the elastic member acting in the direction in which the first valve body is brought into contact with the first seat. Further, when the body operating means is operated to push the second valve body, the elastic force of the elastic body does not act on the operating means, so that the force for operating the operating means can be reduced. Further, the elastic force of the elastic body can be adjusted by changing the contraction amount of the elastic body without being affected by the operation of the valve body operating means.

It is sectional drawing of the principal part of the stop valve which has a slow return function of an example of this invention. It is an expanded sectional view of the valve body unit of FIG. (A) is a perspective view of the 1st valve body of FIG. 1, (b) is sectional drawing of the 1st valve body of (a), (c) is a perspective view of the 2nd valve body of FIG. (A) is a figure of the state which closed the circuit with the stop valve which has a slow return function of Drawing 2, (b) is a figure of the state where the stop valve which has the slow return function of Drawing 2 functions as a slow return valve. It is sectional drawing of the principal part of the stop valve which has a slow return function of another example of this invention. It is an expanded sectional view of the valve body unit of FIG. (A) is a perspective view of the 1st valve body of FIG. 5, (b) is a perspective view of the 2nd valve body of FIG. (A) is a figure of the state which closed the circuit with the stop valve which has the slow return function of FIG. 6, (b) is a figure of the state which the stop valve which has the slow return function of FIG. 6 functions as a slow return valve. It is sectional drawing of the principal part of the stop valve which has a slow return function of another example of this invention. It is sectional drawing of the principal part of the stop valve which has the conventional slow return function.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In this example, a stop valve having a slow return function as an example of the present invention that can be used in a slow lowering device for a working machine when an actuator is a hydraulic lift device for a working machine of a tractor will be described. As shown in FIG. 1, a stop valve 10 having a slow return function includes a first port 11 connected to an actuator, a second port 12 connected to a pump and a tank, and communicated with the first port 11, and a first port. The valve case 13 includes a valve body unit 20 that can block communication between the first port 11 and the second port 12.

  The valve case 13 includes a first seat portion 26 that closes communication between the first port 11 and the second port 12 when the front portion of the valve body unit 20 contacts the first seat portion 26. The first port 11 is formed in front of the front part of the valve body unit 20, and the second port 12 is formed in the rear of the valve body unit 20 from the front part. In addition, an opening is formed in the valve case 13 behind the first seat portion 26 so that the valve body unit 20 can be inserted. The valve body unit 20 has a straight line between the first seat portion 26 and the opening. Can be moved.

  A valve body operating means guide 15 for closing the opening is installed in the valve case 13. The valve element operating means guide 15 is provided with a valve element operating means 14 and includes a screw portion that allows the valve element operating means 14 to move in the front-rear direction by rotating the valve element operating means 14. The valve body operating means guide 15 is sealed so that hydraulic oil does not flow out of the opening. The shape of the valve element operating means guide 15 is not limited to the above, and can be arbitrarily designed as long as the valve element operating means 14 can be moved in the front-rear direction and the opening can be sealed.

  The valve body operating means 14 is formed in a rod shape, and the valve body operating means 14 moves in the front-rear direction by rotating the valve body operating means 14. Further, the valve body operating means 14 can come into contact with the valve body unit 20 via the ball 16 and can move the valve body unit 20 in the front-rear direction. Further, the valve body operating means 14 includes a scale that displays the amount of movement of the valve body operating means 14 in the front-rear direction, and a stopper that fixes the rotation of the valve body operating means 14. In addition, the shape of the valve body operating means 14 is not limited to the above, and can be arbitrarily designed as long as the valve body unit 20 can be moved back and forth by the valve body operating means 14. Further, the ball 16 may not be disposed, and the valve body operating means 14 may be formed integrally with a second valve body 22 described later, or formed integrally with a second valve body 22 and a spring holder 24 described later. .

  As shown in FIGS. 2 and 3A to 3C, the valve body unit 20 is movable in the front-rear direction between the first seat portion 26 and the opening, and is disposed at the front portion. A valve body 21, a second valve body 22 disposed at the rear, and a spring 23 disposed behind the first valve body 21 are provided. A spring holder 24 is provided between the spring 23 and the valve body operating means 14, and a valve body presser 25 is provided between the spring 23 and the first valve body 21.

  The first valve body 21 is configured integrally with a cylindrical body portion 31, and a head portion 32 including a cylindrical portion 33 having a diameter larger than that of the body portion 31, a cylindrical portion 33, and a conical portion 34 having the same diameter. doing. Moreover, the top part of the cone-shaped part 34 is excised, and forms the plane. Further, the first through hole 35 is provided so as to penetrate the inside of the first valve body 21 along the center line of the body portion 31. However, the 1st through-hole 35 is a shape which ensures the flow path which does not act as an aperture | diaphragm | restriction at the time of hydraulic oil passing. With the outer peripheral surface of the conical portion 34 coming into contact with the first seat portion 26 formed in the valve case 13, the hydraulic oil passing through the outside of the valve body unit 20 is connected to the first port 11 and the second port 12. Block communication. In addition, a second seat portion 27 is provided in which the second valve body 22 comes into contact with the outer peripheral surface of the hole forming the first through hole 35. When the second valve body 22 abuts on the second seat portion 27, the first through hole 35 is closed, and the hydraulic oil passing through the valve body unit 20 is connected to the first port 11 and the second port 12. Block communication.

  Further, the first valve body 21 includes a second through hole 36 that penetrates in the diameter direction of the body portion 31 slightly behind the second seat portion 27. The second through holes 36 are provided radially, and the angle formed by the center lines of the two adjacent second through holes 36 is 45 °. If the first through hole 35 and the second port 12 communicate with each other without forming a restriction between the first through hole 35 and the second port 12 in a state where the first through hole 35 is not closed. The shape and the number of the second through holes 36 are not limited to the above, and the second through holes 36 may not be provided.

  The second valve body 22 integrally includes a cylindrical body portion 37, a body portion 37, and a conical head portion 38 having the same diameter, and is inserted into the first through hole 35 from the rear. The first port 11 and the second port are used for the hydraulic fluid that closes the first through hole 35 and passes through the inside of the valve body unit 20 by the outer peripheral surface of the head portion 38 coming into contact with the second seat portion 27. Communication with 12 is blocked. Here, the second valve body 22 only needs to allow at least a part of the head portion 38 to move from the rear in the first through hole 35, and the body portion 37 and the head portion 38 are inserted into the first through hole 35. There is no need to be. Therefore, if the second valve body 22 has at least a part of the head 38 inserted into the first through hole 35, the outer peripheral surface of the hole forming the first through hole 35 is moved when the second valve body 22 moves. The second sheet portion 27 can be reliably abutted and the first through hole 35 can be reliably closed. Further, the second valve body 22 may be formed integrally with the spring holder 24, and further may be formed integrally with the valve body operating means 14. Reference numeral 42 denotes a gap between the outer peripheral surface of the head 38 and the second sheet portion 27.

  Accordingly, the first seat portion 26 is formed in the valve case 13 and comes into contact with the outer peripheral surface of the conical portion 34 of the first valve body 21 to remove the flow path passing through the first through hole 35. The communication between the first port 11 and the second port 12 is blocked. Further, the second seat portion 27 closes the first through hole 35 by contacting the outer peripheral surface of the head portion 38 of the second valve body 22.

  Therefore, when the first valve body 21 and the first seat portion 26 come into contact with each other and the second valve body 22 and the second seat portion 27 come into contact with each other, the communication between the first port 11 and the second port 12 is established. Is blocked.

  The spring 23 is disposed in a contracted state with both end portions in contact with the valve body presser 25 and the spring holder 24. Further, the body portion 31 of the first valve body 21 is accommodated in the spring 23. Therefore, when the valve body unit 20 moves, the spring 23 serves as a guide, so that the valve body unit 20 can move integrally without disturbing the mounting structure. The elastic force of the spring 23 acts in a direction in which the first valve body 21 is brought into contact with the first seat portion 26 via the valve body presser 25. Accordingly, the followability of the first valve body 21 to the first seat portion 26 can be improved. The spring 23 is not limited to a coil spring, and may be any elastic member such as various compression springs or a cylindrical rubber member as long as it has a repulsive force when contracted. Moreover, it is good also as a structure without the spring 23. FIG.

  The spring holder 24 is formed in a columnar shape, is in contact with the spring 23 and the second valve body 22 at the front end face, and is in contact with the valve body operating means 14 via the ball 16 at the rear end face. Further, by operating the valve body operating means 14, the spring holder 24 moves forward and the spring 23 is contracted, but the first holder 21 and the spring holder 24 are prevented from coming into contact with each other. A depression is formed in the front side end face of.

  The valve body presser 25 is formed in a cylindrical shape, and the body part 31 of the first valve body 21 is inserted into the cylinder, and the front side end face abuts on the columnar part 33 of the first valve body 21, and the rear side end face Is in contact with the spring 23. Further, a gap through which hydraulic oil can flow is provided between the inside of the cylinder and the body portion 31 of the first valve body 21. Moreover, the hole 39 penetrated in the diameter direction is provided. If the hole 39 has a shape that allows the second port 12 and the first through hole 35 to communicate with each other and that ensures a flow path that does not act as a throttle when the hydraulic oil passes, the hole 39 may be a round hole or a square hole. May be arbitrarily designed.

  The material of the valve case 13, the valve body operating means 14, the valve body operating means guide 15, the ball 16, the first valve body 21, the second valve body 22, the spring holder 24, and the valve body presser 25 is a strength that forms a valve. If it has, it will not specifically limit, For example, iron, stainless steel, etc. are mentioned. Further, the working fluid is not particularly limited to oil, and may be water. When water is used as the working fluid, the material of the valve components is preferably stainless steel that is not easily oxidized. Further, in order to prevent oxidation by water, surface treatment may be applied to the components of the valve.

  Next, the operation of the stop valve having the slow return function configured as described above will be described. When the pressure P1 of the first port 11 is equal to the pressure P2 of the second port 12 (P1 = P2), that is, when a constant pressure is maintained in the actuator, the valve body operating means 14 is operated to operate the valve body. When the operation means 14 is moved forward, the valve body unit 20 moves forward via the ball 16 and moves until the first valve body 21 contacts the first seat portion 26. At this time, the pressure of the hydraulic oil is applied as resistance to the operating force of the valve body operating means 14. Further, when the valve element operating means 14 is operated to move the valve element operating means 14 forward, the spring 23 is contracted. This state is the state shown in FIG. 2, which is the initial installation state of the valve of the present invention. Here, since the elastic force of the spring 23 is acting on the first valve body 21, the first valve body 21 is the first valve body 21 unless an external force larger than the elastic force acts on the first valve body 21 in the rearward direction. It remains in contact with the sheet 26.

  If the valve element operating means 14 is further operated from the above-described state to move the valve element operating means 14 forward, the outer peripheral surface of the head 38 of the second valve element 22 becomes the first as shown in FIG. The first through hole 35 is closed by contacting the two sheet portions 27. It should be noted that the pressure of the hydraulic oil and the force for contracting the spring are added as resistance to the operating force of the valve body operating means 14 at this time. Moreover, the 1st valve body 21 is pinched | interposed by the 1st seat part 26 and the 2nd valve body 22, and cannot move back and forth. Therefore, the communication between the first port 11 and the second port 12 is blocked, and functions as a stop valve.

  Next, in the state shown in FIG. 2, when the pressure P1 of the first port 11 is higher than the pressure P2 of the second port 12 (P1> P2), that is, from the actuator communicating with the first port 11 to the second port 12 The operation of the stop valve having a slow return function when the working oil is allowed to flow through the communicating tank and the work implement is slowly lowered will be described.

  As shown in FIG. 4 (b), the first valve body 21 overcomes the elastic force of the spring due to the pressure difference between the first port 11 and the second port 12, moves backward, and the head of the second valve body 22. The outer peripheral surface of the portion 38 contacts the second sheet portion 27. Accordingly, the first through hole 35 is closed, and a gap 41 is formed between the outer peripheral surface of the conical portion 34 of the first valve body 21 and the first seat portion 26. The hydraulic oil flowing from the first port 11 to the second port 12 passes only through this gap 41, but the gap 41 serves as a throttle, so the flow rate of the hydraulic oil flowing from the first port 11 to the second port 12 is limited. Is done. That is, the gap 41 serves as a slow return throttle, which acts as a slow return valve, and slowly lowers the work implement.

  Here, the lowering speed of the work implement can be adjusted by changing the size of the gap 41 which is a slow return throttle. The size of the gap 41 is determined by the movable range of the first valve body 21. Therefore, it can be adjusted by changing the position of the second valve body 22 in the initial state by operating the valve body operating means 14.

  Next, in the state shown in FIG. 2, when the pressure P1 of the first port 11 is smaller than the pressure P2 of the second port 12 (P1 <P2), that is, from the pump communicating with the second port 12, the first port 11 The operation of the stop valve having a slow return function when the working oil is caused to flow through the communicating actuator and the work machine is raised will be described.

  The first valve body 21 is in contact with the first seat portion 26 by the elastic force of the spring 23, but a force is applied forward due to the pressure difference between the first port 11 and the second port 12, and the first seat Further pressed against the portion 26. Accordingly, the gap 41 is reliably closed, and the gap 42 between the outer peripheral surface of the head portion 38 of the second valve body 22 and the second seat portion 27 is maintained. The hydraulic fluid flowing from the second port 12 to the first port 11 sequentially passes through the through hole 39, the second through hole 36, the gap 42, and the first through hole 35. Since any flow path does not serve as a throttle, the flow rate of the hydraulic oil flowing from the second port 12 to the first port 11 is not limited. That is, the valve body unit 20 does not act as a resistance in the fluid circuit, and hinders the response of the actuator, so that the work machine is raised with good response.

  Here, the gap 41 needs to be smaller than the minimum cross-sectional area of the flow path connecting the first port 11 and the second port 12. That is, the first valve body 21 and the first seat portion 26 are designed so that the gap 41 acts as a throttle. Further, the gap 42 needs to be larger than the minimum cross-sectional area of the flow path connecting the first port 11 and the second port 12. That is, the first valve body 21 and the second valve body 22 are designed so that the gap 42 does not act as a throttle.

  Moreover, you may comprise the stop valve which has a slow return function as shown in FIG.5, FIG.6 and FIG.7 (a) (b). The valve body unit 20 ′ includes a first valve body 21 ′, a second valve body 22 ′ formed integrally with a spring holder, and a spring 23.

  Here, reference numeral 26 'denotes a first seat portion, 27' denotes a second seat portion, 31 'denotes a body portion of the first valve body 21', 32 'denotes a head portion of the first valve body 21', and 33 'denotes a head portion. The cylindrical portion of the portion 31 ′, 34 ′ is the conical portion of the head portion 31 ′, 35 ′ is the first through hole, 37 ′ is the body portion of the second valve body 22 ′, and 38 ′ is the second valve body 22 ′. The head portion 42 'indicates a gap between the outer peripheral surface of the head portion 38' and the second sheet portion 27 '. In addition, the first valve body 21 ′ is the first valve body 21 in the above example, the second valve body 22 ′ is the second valve body 22, the first seat portion 26 ′ is the first seat portion 26, the second seat The seat portion 27 ′ is the second seat portion 27, the trunk portion 31 ′ is the trunk portion 31, the head portion 32 ′ is the head portion 32, the columnar portion 33 ′ is the columnar portion 33, and the conical portion 34 ′ is In the conical portion 34, the first through hole 35 ′ corresponds to the first through hole 35, the body portion 37 ′ corresponds to the body portion 37, the head portion 38 ′ corresponds to the head portion 38, and the gap 42 ′ corresponds to the gap 42. .

  The first valve body 21 'includes a cylindrical body portion 31', a columnar portion 33 'having a diameter larger than that of the body portion 31', and a conical portion 34 'having the same diameter as the columnar portion 33'. 32 'is integrally formed. The top of the conical portion 34 'is cut off to form a flat surface. Further, a first through hole 35 ′ is provided so as to penetrate the first valve body 21 ′ along the center line of the body portion 31 ′. However, the first through hole 35 ′ has a shape that ensures a flow path that does not act as a throttle when hydraulic fluid passes through. The first port 11 and the second port for the hydraulic fluid passing outside the valve body unit 20 ′ by the outer peripheral surface of the conical portion 34 ′ coming into contact with the first seat portion 26 ′ formed in the valve case 13 Communication with 12 is blocked. In addition, a second seat portion 27 ′ is provided in which the second valve body 22 ′ is in contact with the rear end portion of the outer peripheral surface of the hole forming the first through hole 35 ′. When the second valve body 22 ′ abuts on the second seat portion 27 ′, the first port 11 and the second oil are closed with respect to the hydraulic fluid that closes the first through hole 35 ′ and passes through the inside of the valve body unit 20 ′. Communication with the port 12 is blocked.

  The second valve body 22 ′ is configured by integrally forming a cylindrical body portion 37 ′ and a cone-shaped head portion 38 ′ having the same diameter as the body portion 37 ′, and the head portion 38 from the rear is formed in the first through hole 35 ′. A part of 'is inserted. And the 1st port 11 is about the hydraulic fluid which obstruct | occludes 1st through-hole 35 'and passes the inside of valve body unit 20' because the outer peripheral surface of head 38 'contact | abuts to 2nd sheet | seat part 27'. And the communication with the second port 12 is blocked. Here, since a part of the head portion 38 'is inserted into the first through hole 35' from the rear, the outer peripheral surface of the hole forming the first through hole 35 'is in the movement of the second valve body 22'. It plays the role of a guide, can contact | abut with 2nd sheet | seat part 27 'reliably, and can obstruct | occlude 1st through-hole 35' reliably. Further, the rear end portion is provided with a flange portion that contacts the spring 23.

  The spring 23 has a front end surface in contact with the cylindrical portion 33 ′ of the first valve body 21 ′ and a rear side end surface in contact with a flange portion formed at the rear end portion of the second valve body 22 ′. It is arranged in the state. The spring 23 houses the body 31 'of the first valve body 21' and the body 37 'of the second valve body 22'. Therefore, when the valve body unit 20 'moves, the spring 23 serves as a guide, so that the valve body unit 20' can move together without disturbing the mounting structure. Further, the elastic force of the spring 23 acts in a direction in which the first valve body 21 ′ is brought into contact with the first seat portion 26 ′. Accordingly, the followability of the first valve body 21 'to the first seat portion 26' can be improved.

  Next, the operation of the stop valve having the slow return function configured as described above will be described. When the pressure P1 of the first port 11 is equal to the pressure P2 of the second port 12 (P1 = P2), that is, when a constant pressure is maintained in the actuator, the valve body operating means 14 is operated to operate the valve body. When the operating means 14 is moved forward, the valve body unit 20 ′ moves forward via the ball 16 and moves until the first valve body 21 ′ contacts the first seat portion 26 ′. At this time, the pressure of the hydraulic oil is applied as resistance to the operating force of the valve body operating means 14. Further, when the valve element operating means 14 is operated to move the valve element operating means 14 forward, the spring 23 is contracted. This state is the state shown in FIG. 6, which is the initial installation state of the valve of the present invention. Here, since the elastic force of the spring 23 is acting on the first valve body 21 ′, the first valve body 21 ′ is not subject to the first valve body 21 ′ unless an external force larger than this elastic force acts backward. Remains in contact with the first sheet 26 '.

  When the valve element operating means 14 is further operated from the above state to move the valve element operating means 14 forward, as shown in FIG. 8A, the outer peripheral surface of the head 38 'of the second valve element 22'. Is in contact with the second sheet portion 27 ′ to close the first through hole 35 ′. It should be noted that the pressure of the hydraulic oil and the force for contracting the spring are added as resistance to the operating force of the valve body operating means 14 at this time. The first valve body 21 'is sandwiched between the first seat portion 26' and the second valve body 22 'and cannot move back and forth. Therefore, the communication between the first port 11 and the second port 12 is blocked, and functions as a stop valve.

  Next, in the state shown in FIG. 6, when the pressure P1 of the first port 11 is higher than the pressure P2 of the second port 12 (P1> P2), that is, from the actuator communicating with the first port 11 to the second port 12 The operation of the stop valve having a slow return function when the working oil is allowed to flow through the communicating tank and the work implement is slowly lowered will be described.

  As shown in FIG. 8B, the first valve body 21 ′ overcomes the elastic force of the spring due to the pressure difference between the first port 11 and the second port 12, moves rearward, and the second valve body 22 ′. The outer peripheral surface of the head portion 38 'comes into contact with the second sheet portion 27'. Accordingly, the first through hole 35 ′ is closed and a gap 41 ′ is formed between the outer peripheral surface of the conical portion 34 ′ of the first valve body 21 ′ and the first seat portion 26 ′. The hydraulic fluid flowing from the first port 11 to the second port 12 passes only through this gap 41 ′, but the gap 41 ′ serves as a throttle, so the flow rate of hydraulic fluid flowing from the first port 11 to the second port 12 Is limited. That is, the gap 41 'serves as a slow return throttle, which acts as a slow return valve, and slowly lowers the work implement.

  Here, the lowering speed of the work implement can be adjusted by changing the size of the gap 41 'which is a slow return throttle. The size of the gap 41 'is determined by the movable range of the first valve body 21'. Therefore, it can be adjusted by changing the position of the second valve body 22 ′ in the initial state by operating the valve body operating means 14.

  Next, in the state shown in FIG. 6, when the pressure P1 of the first port 11 is smaller than the pressure P2 of the second port 12 (P1 <P2), that is, from the pump communicating with the second port 12, The operation of the stop valve having a slow return function when the working oil is caused to flow through the communicating actuator and the work machine is raised will be described.

  The first valve body 21 ′ is in contact with the first seat portion 26 ′ by the elastic force of the spring 23, but a force is applied forward due to the pressure difference between the first port 11 and the second port 12, The sheet is further pressed against the sheet portion 26 '. Accordingly, the gap 41 ′ is reliably closed, and the gap 42 ′ is maintained between the outer peripheral surface of the head 38 ′ of the second valve body 22 ′ and the second seat portion 27 ′. The hydraulic fluid flowing from the second port 12 to the first port 11 sequentially passes through the gap 42 'and the first through hole 35'. Since any flow path does not serve as a throttle, the flow rate of the hydraulic oil flowing from the second port 12 to the first port 11 is not limited. That is, the valve body unit 20 does not act as a resistance in the fluid circuit, and hinders the response of the actuator, so that the work machine is raised with good response.

  Here, the gap 41 ′ needs to be smaller than the minimum cross-sectional area of the flow path that connects the first port 11 and the second port 12. That is, the first valve body 21 ′ and the first seat portion 26 ′ are designed so that the gap 41 ′ acts as a throttle. Further, the gap 42 ′ needs to be larger than the minimum cross-sectional area of the flow path connecting the first port 11 and the second port 12. That is, the first valve body 21 'and the second valve body 22' are designed so that the gap 42 'does not act as a throttle.

  By adopting such a configuration, the number of parts can be reduced, and each part has a simple shape, thereby improving productivity and maintainability.

  A stop valve having a slow return function may be configured as shown in FIG. The valve body unit 20 ″ includes a first valve body 21 ″, a second valve body 22 ″ integrally formed with a valve body operating means, and a spring 23.

  Here, reference numeral 26 ″ denotes a first seat portion, 27 ″ denotes a second seat portion, and 35 ″ denotes a first through hole. Further, the first valve body 21 ″ corresponds to the first valve body 21 in the above-described example, The second valve body 22 ″ is the second valve body 22, the first seat portion 26 ″ is the first seat portion 26, the second seat portion 27 ″ is the second seat portion 27, and the first through hole 35 ″ is the first through hole 35 ″. It corresponds to 1 through hole 35 respectively.

  The first valve body 21 ″ is formed in the same manner as the first valve body 21 ′. The second valve body 21 ″ eliminates the flange portion formed at the rear end portion of the second valve body 22 ′. At the same time, it is formed integrally with the valve body operating means 14. The spring 23 is disposed in a contracted state with the front end surface in contact with the cylindrical portion of the first valve body 21 ″ and the rear end surface in contact with the valve body operating means guide 15. The body of the first valve body 21 ″ is accommodated in the spring 23. Therefore, when the first valve body 20 ″ moves, the spring 23 serves as a guide, so that the first valve body 20 ″ can move together without disturbing the mounting structure with the spring 23. . Further, the elastic force of the spring 23 acts in a direction in which the first valve body 21 ″ is brought into contact with the first seat portion 26 ″. Accordingly, the followability of the first valve body 21 ″ to the first seat portion 26 ″ can be improved. The remaining configuration of the valve body unit 20 ″ is the same as that of the valve body unit 20 ′.

  Next, the operation of the stop valve having the slow return function configured as described above will be omitted because it is the same operation as the valve body unit 20 '.

  By adopting such a configuration, the number of parts can be reduced, and each part has a simple shape, thereby improving productivity and maintainability. Further, when the valve element operating means 14 is operated to move forward, the elastic force of the spring 23 does not act on the valve element operating means 14, so that the force for operating the valve element operating means 14 can be reduced. Further, since the amount of contraction of the spring 23 can be changed by the amount of pushing from the opening of the valve element operating means guide 15, the elastic force of the spring can be adjusted without being affected by the operation of the valve element operating means 14. Can do.

  The present invention is not limited to the above-described example, and can take any form within a scope not departing from the gist of the invention.

  The stop valve having a slow return function of the present invention can be used for a slow lowering device for a working machine when the actuator is a hydraulic lift device for a working machine of a tractor, but is not limited thereto, The present invention can be applied to a stop valve having a slow return function used for any fluid circuit.

DESCRIPTION OF SYMBOLS 10 Stop valve which has a slow return function 11 1st port 12 2nd port 13 Valve case 14 Valve body operation means 15 Valve body operation means guide 20, 20 ', 20 "Valve body unit 21, 21', 21" 1st valve Body 22, 22 ', 22 "Second valve body 23 Spring 26, 26', 26" First seat part 27, 27 ', 27 "Second seat part 31, 31' Body part 32, 32 of first valve body 'Head of first valve body 35, 35', 35 "First through hole 37, 37 'Body portion of second valve body 38, 38' Head of second valve body

Claims (5)

A first port connected to the actuator;
A second port connected to the pump and the tank and in communication with the first port;
A valve case including a valve body unit capable of closing communication between the first port and the second port;
In the stop valve having a slow return function that closes the communication between the first port and the second port by contacting the front portion of the valve body unit with the first seat portion formed in the valve case,
The valve body unit is composed of a first valve body and a second valve body,
The first valve body is configured integrally with a cylindrical body portion and a head portion that comes into contact with the first seat portion,
Forming a first through hole so as to penetrate the first valve body along the center line of the body portion;
Enabling the first port and the second port to communicate with each other through the first through hole;
A stop valve having a slow return function that allows the second valve body to move from the rear in the first through hole,
A second seat portion is formed in the body portion of the first valve body, and the second valve body is configured integrally with a cylindrical body portion and a head portion that contacts the second seat portion,
By contacting the head of the second valve body with the second seat portion, the first through hole is closed and the communication between the first port and the second port is closed. Stop valve with slow return function.   The elastic member is provided between the first valve body and the second valve body, and the elastic member is contracted by the first valve body and the second valve body. A stop valve having a slow return function described in 1.   3. The valve case according to claim 1, further comprising: a valve body operating unit that contacts the rear part of the second valve body to move the valve body unit through a valve body operating unit guide. 4. Stop valve with slow return function.   The stop valve having a slow return function according to claim 3, wherein the second valve body and the valve body operating means are integrally formed.   An elastic member is provided between the first valve body and the valve body operating means guide, and the elastic member is contracted by the first valve body and the valve body operating means guide. Item 5. A stop valve having a slow return function according to Item 3 or 4.

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