阅读说明：本技术 阀构造体和作业机械 (Valve structure and working machine ) 是由 山本良宏 冈田泰辅 于 2019-07-26 设计创作，主要内容包括：本发明提供一种能够抑制阀芯的振动的简单的构造的阀构造体和作业机械。阀构造体(10)具备：阀芯(11)、阀座构件(12)以及按压部(14)。阀芯(11)和阀座构件(12)沿着轴向(da)排列配置。按压部(14)具有弹簧(13),利用该弹簧13将阀芯(11)朝向阀座构件(12)推压。按压部(14)基于弹簧(13)的构造使轴向(da)的弹性力和与轴向(da)成直角的径向(dr)的弹性力作用于阀芯(11)。(The invention provides a valve structure and a working machine with a simple structure, which can restrain the vibration of a valve core. A valve structure (10) is provided with: a valve element (11), a valve seat member (12), and a pressing portion (14). The valve element (11) and the valve seat member (12) are arranged in an axial direction (da). The pressing part (14) has a spring (13), and the valve element (11) is pressed toward the valve seat member (12) by the spring (13). The pressing portion (14) causes an elastic force in the axial direction (da) and an elastic force in the radial direction (dr) perpendicular to the axial direction (da) to act on the valve body (11) based on the structure of the spring (13).)

1. A valve structure body, wherein,

the valve structure comprises:

a valve element and a valve seat member arranged in an axial direction; and

and a pressing portion that has a spring, presses the valve element toward the valve seat member by the spring, and causes the valve element to be acted upon by an elastic force in the axial direction and an elastic force in a radial direction perpendicular to the axial direction based on a structure of the spring.

2. A valve structure body, wherein,

the valve structure comprises:

a valve element and a valve seat member arranged in an axial direction;

a pressing portion having a spring, the spring pressing the valve body toward the valve seat member; and

and an elastic adjustment member for adjusting the elasticity of the spring, which has the same position in the axial direction as at least a part of the spring, and which causes the axial elastic force and a radial elastic force perpendicular to the axial direction to act on the valve body from the pressing portion.

3. The valve construct of claim 1 wherein,

the spring is provided to be elastically deformable in the axial direction, and is provided to be elastically deformable in the radial direction.

4. The valve construction of claim 2,

the spring is provided to be elastically deformable in the axial direction, and is provided to be elastically deformable in the radial direction.

5. The valve construct of claim 1 wherein,

the spring is curved along a curve extending in the axial direction and extending in the radial direction.

6. The valve construction of claim 2,

the spring is curved along a curve extending in the axial direction and extending in the radial direction.

7. The valve construct of claim 1 wherein,

the spring has an end face which is an end face contacting the valve element and extends nonparallel to the radial direction.

8. The valve construction of claim 2,

the spring has an end face which is an end face contacting the valve element and extends nonparallel to the radial direction.

9. The valve construction of claim 2,

the elastic adjustment member restrains a portion of the spring to restrict the axial movement of the portion.

10. The valve construct of claim 1 wherein,

the spring has another end surface provided on the opposite side of the one end surface in contact with the valve element and extending in parallel with the radial direction.

11. The valve construction of claim 2,

the spring has another end surface provided on the opposite side of the one end surface in contact with the valve element and extending in parallel with the radial direction.

12. The valve construct of claim 1 wherein,

the spring has an end face which is an end face contacting the spool and extends parallel to the radial direction.

13. The valve construction of claim 2,

the spring has an end face which is an end face contacting the spool and extends parallel to the radial direction.

14. The valve construct of claim 1 wherein,

the valve structure comprises:

a main valve unit for closing or opening a 1 st connection path between the 1 st flow path and the 2 nd flow path; and

a sub-valve unit that closes or opens a 2 nd connection path between a 3 rd flow path and a 4 th flow path, the 3 rd flow path communicating with the 1 st flow path,

at least one of the parent valve unit and the child valve unit includes the valve element, the valve seat member, and the pressing portion.

15. The valve construction of claim 2,

the valve structure comprises:

a main valve unit for closing or opening a 1 st connection path between the 1 st flow path and the 2 nd flow path; and

a sub-valve unit that closes or opens a 2 nd connection path between a 3 rd flow path and a 4 th flow path, the 3 rd flow path communicating with the 1 st flow path,

at least one of the parent valve unit and the child valve unit includes the valve element, the valve seat member, and the pressing portion.

16. A working machine, wherein,

the work machine is provided with the valve structure according to any one of claims 1 to 15.

Technical Field

The present invention relates to a valve structure such as a relief valve and a working machine.

Background

In general, a relief valve is placed in a closed valve state by pressing a valve element urged by a compression coil spring against a valve seat, and placed in an open valve state by separating the valve element, which receives pressure from a working fluid against the pressing force of the compression coil spring, from the valve seat. Since the valve body becomes unstable in the open valve state, it tends to vibrate in the radial direction. The valve body vibrates and repeatedly collides with a component such as a valve seat, thereby generating noise (particularly, high-frequency sound), and there is a fear that the component such as the valve body and the valve seat is damaged and the life is shortened.

Patent documents 1 to 3 disclose techniques for reducing the vibration of such a valve body. For example, in the pressure control valve of patent document 1, the support surface of the spring seat is inclined, and only a part of the valve element is separated from the valve seat while the valve element is partially pressed against the valve seat at the time of opening the valve, thereby preventing the valve element from vibrating. In the relief valve disclosed in patent document 2, the surface of the piston that contacts the sub-valve is inclined, thereby preventing vibration in the radial direction of the sub-valve. In addition, with the valve disclosed in patent document 3, the spring holding member formed of a material having a lower elastic coefficient than that of the compression coil spring holds the compression coil spring in contact with the compression coil spring, so that the movement of the compression coil spring in the radial direction is restricted and the vibration of the valve body is suppressed.

Disclosure of Invention

Problems to be solved by the invention

According to the valve structures of patent documents 1 to 3, the following new proposals for the valve structures are desired: the vibration of the valve body can be suppressed when the valve is opened, but the valve body is more simply structured, the vibration of the valve body can be efficiently suppressed, and the valve body can be manufactured at low cost.

For example, in the valve structures of patent documents 1 and 2, it is necessary to form a slant surface on the spring seat or a slant surface on the piston. The work of forming such an inclined surface on each member takes time and labor, and high processing accuracy is required to make the inclination angle of the inclined surface equal to a desired angle. In addition, in the valve structures of patent documents 1 and 3, it is necessary to provide a spring seat having an inclined surface and a spring holding member. Such provision of special additional elements not only increases the cost, but also complicates the structure and requires labor and time for manufacturing. In the valve structure of patent document 1, the inclination of the spring seat is used to adjust the posture of the spring, thereby indirectly preventing the valve body from vibrating. Such an indirect method is difficult to efficiently suppress the vibration of the valve body, and it is necessary to form an optimum inclined surface in the spring seat depending on the spring to be actually used. In the valve structure of patent document 1, the spring seat needs to be disposed at a position offset from the spring in the axial direction, and therefore the structure tends to be complicated in the axial direction and to be large in size.

As described above, as a valve structure for suppressing vibration of the valve body when the valve is opened, a valve structure having a simple structure (particularly, a valve structure capable of preventing complication and enlargement of the structure in the axial direction), a valve structure capable of suppressing vibration efficiently, and a valve structure capable of being manufactured at low cost are desired.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a valve structure and a working machine having a simple structure capable of suppressing vibration of a valve body, and to provide a valve structure and a working machine capable of preventing, for example, the structure in the axial direction from being complicated and large-sized. Further, it is an object to provide a valve structure and a working machine capable of efficiently suppressing vibration of a valve body. Further, it is an object to provide a valve structure and a working machine which can suppress vibration of a valve body and can be manufactured at low cost.

Means for solving the problems

One aspect of the present invention relates to a valve structure including: a valve element and a valve seat member arranged in an axial direction; and a pressing portion that has a spring, presses the valve element toward the valve seat member by the spring, and causes an elastic force in an axial direction and an elastic force in a radial direction perpendicular to the axial direction to act on the valve element based on a structure of the spring.

Another aspect of the present invention relates to a valve structure including: a valve element and a valve seat member arranged in an axial direction; a pressing portion having a spring, the valve body being pressed toward the valve seat member by the spring; and an elastic adjustment member for adjusting the elasticity of the spring, the position of which in the axial direction is the same as the position of at least a part of the spring in the axial direction, and which causes an elastic force in the axial direction and an elastic force in a radial direction perpendicular to the axial direction to act on the valve body from the pressing portion.

The spring may be provided to be elastically deformable in the axial direction and may be provided to be elastically deformable in the radial direction.

It is also possible that the spring is curved along a curve extending in the axial direction and extending in the radial direction.

The spring may have an end face which is an end face contacting the valve element and extends in a direction not parallel to the radial direction.

The elastic adjustment member may restrict a part of the spring to restrict the part from moving in the axial direction.

The spring may have another end surface provided on the opposite side of the one end surface in contact with the valve element and extending in parallel with the radial direction.

The spring may have an end surface that is an end surface that contacts the valve element and extends parallel to the radial direction.

The valve structure may include: a main valve unit for closing or opening a 1 st connection path between the 1 st flow path and the 2 nd flow path; and a sub-valve unit that closes or opens a 2 nd connection path between a 3 rd flow path and a 4 th flow path, the 3 rd flow path communicating with the 1 st flow path, at least one of the main valve unit and the sub-valve unit including a valve body, a valve seat member, and a pressing portion.

Another aspect of the present invention relates to a working machine including the valve structure.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a valve structure having a simple structure that can suppress vibration of a valve element. Further, according to the present invention, it is possible to provide a valve structure capable of efficiently suppressing vibration of a valve body. Further, according to the present invention, it is possible to provide a valve structure that can suppress vibration of a valve body, which can be manufactured at low cost.

Drawings

Fig. 1 is a schematic main-part sectional view illustrating a valve structure according to an embodiment of the present invention.

Fig. 2 is a schematic main-part sectional view illustrating a valve structure according to an embodiment of the present invention.

Fig. 3 is a schematic diagram showing a cross-sectional structure example of the spring.

Fig. 4 is a schematic diagram showing a cross-sectional structure example of the spring.

Fig. 5 is a schematic diagram showing a cross-sectional structure example of the spring.

Fig. 6 is a longitudinal sectional side view of the relief valve.

Fig. 7 is a schematic external view showing a typical configuration example of a hydraulic excavator (working machine).

Description of the reference numerals

10. A valve structure; 11. a valve core; 12. a valve seat member; 13. a spring; 14. a pressing part; 30. an elastic adjustment member; 41. 1 st connection path; 42. a 2 nd connection path; 50. an overflow valve; 210. a hydraulic excavator (working machine); A. an axis; as, spring center axis; C. a gap; da. Axial direction; dr, radial; e1, rim; e2, rim; r1, flow path 1; r2, flow path 2; s1, an end face; s2, the other end face.

Detailed Description

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 and 2 are main partial sectional views schematically illustrating a valve structure 10 according to an embodiment of the present invention. The valve structure 10 includes a valve element 11, a valve seat member 12, and a pressing portion 14.

The valve body 11 and the valve seat member 12 are arranged in parallel in the axial direction da, and the size of the gap C therebetween is variable. The axial direction da is a direction in which the valve body 11 is movable in the 2 nd flow passage R2 formed in the valve seat member 12, and is a direction along the axis a (for example, the central axis of the valve structure 10) that passes through the valve structure 10 in the longitudinal direction.

The pressing portion 14 has a spring 13, and presses the valve body 11 toward the valve seat member 12 by the spring 13. Typically, the spring 13 is a coil spring, but the specific structure is not limited, and it is a mechanical element utilizing the following properties: when the force is applied, the elastic deformation is generated, and when the force is released, the original state is restored. In the valve structure 10 shown in fig. 1 and 2, the bottom surface (upper side surface in fig. 1 and 2) of the valve element 11 formed in a conical shape is pressed toward the edge portions E1 and E2 (downward in fig. 1 and 2) of the valve seat member 12 in the axial direction da by a spring (compression coil spring) 13.

The valve seat member 12 has a 1 st flow path R1 and a 2 nd flow path R2 that are adjacently arranged in the axial direction da, and a working fluid (including liquid and gas) such as pressure oil flows through the 1 st flow path R1 and the 2 nd flow path R2. The 1 st flow path R1 and the 2 nd flow path R2 each have a circular cross section and have a substantially cylindrical (i.e., cylindrical) shape with the axis a as a center axis. In a radial direction dr perpendicular to the axial direction da, the diameter (diameter) of the 1 st flow path R1 is smaller than the maximum diameter (maximum diameter) of the valve body 11, and the diameter of the 2 nd flow path R2 is larger than the maximum diameter of the valve body 11. Therefore, a step portion including the rim portions E1 and E2 of the seat member 12 is formed at the boundary between the 1 st flow path R1 and the 2 nd flow path R2. In the 2 nd flow path R2, the spool 11 is reciprocally movable in the axial direction da. Further, a front portion (a lower portion of the valve body 11 in fig. 1 and 2) of the valve body 11 having a smaller cross-sectional area than the diameter of the 1 st flow passage R1 (particularly, the diameter of the radial direction dr at the edge portions E1 and E2) can move in and out of the 1 st flow passage R1 in the axial direction da. On the other hand, the rear portion (the upper portion of the valve body 11 in fig. 1 and 2) of the valve body 11 having a size equal to or larger than the diameter of the 1 st flow path R1 (particularly, the diameter of the radial dr at the edge portions E1 and E2) is obstructed by the valve seat member 12 (particularly, the edge portions E1 and E2) and cannot enter the 1 st flow path R1.

The 1 st and 2 nd flow paths R1 and R2 are filled with the working fluid, and the position in the axial direction da of the spool 11 is determined by the difference between the pressure of the working fluid in the 1 st flow path R1 and the pressure of the working fluid in the 2 nd flow path R2. When the difference between the pressure of the working fluid in the 1 st flow path R1 and the pressure of the working fluid in the 2 nd flow path R2 is within a predetermined range, the valve body 11 is pressed by the spring 13 of the pressing portion 14 and comes into close contact with the edge portions E1 and E2 of the valve seat member 12. In this case, as shown in fig. 1, there is no clearance C between the valve body 11 and the valve seat member 12 (that is, "the size of the clearance C in the axial direction da is 0 (zero)"), and the 1 st flow path R1 and the 2 nd flow path R2 are blocked by the valve body 11, and the working fluid does not substantially flow between the 1 st flow path R1 and the 2 nd flow path R2. Therefore, the pressure of the working fluid in the 1 st flow path R1 and the pressure of the working fluid in the 2 nd flow path R2 do not affect each other.

On the other hand, when the pressure of the working fluid in the 1 st flow path R1 is higher than the pressure of the working fluid in the 2 nd flow path R2 and the difference between the pressure of the working fluid in the 1 st flow path R1 and the pressure of the working fluid in the 2 nd flow path R2 exceeds a predetermined range, the valve body 11 moves against the pressing force of the spring 13 of the pressing portion 14, and a gap C is formed between the valve body 11 and the valve seat member 12 (that is, "the size of the gap C in the axial direction da > 0"). By forming the clearance C, the working fluid flows from the 1 st flow path R1 to the 2 nd flow path R2, and the pressure of the working fluid in the 1 st flow path R1 is reduced. The predetermined range here is determined by the force acting on the valve body 11 in the axial direction da, and is determined by the elastic force applied to the valve body 11 from the pressing portion 14 (spring 13) and the force applied to the valve body 11 from the working fluid.

In the valve structure 10 described above, the pressing portion 14 of the present embodiment causes the elastic force in the axial direction da and the elastic force in the radial direction dr to act on the valve body 11 based on at least one of the structure of the spring 13 and an elastic adjustment member (see reference numeral "30" in fig. 5, which will be discussed later) that adjusts the elasticity of the spring 13. That is, the pressing portion 14 can cause the elastic force in the axial direction da and the elastic force in the radial direction dr to act on the valve body based on the configuration of the spring 13. Further, the elastic force in the axial direction da and the elastic force in the radial direction dr can be applied to the valve body 11 from the pressing portion 14 by the elastic adjustment member. Further, the case where the spring 13 causes the elastic force to act on the spool 11 in the radial direction dr does not include the following case: the spring 13 applies different plural-directional elastic forces to the spool 11, and the plural-directional elastic forces cancel each other out so that the elastic force from the spring 13 does not substantially act on the spool 11 in the radial direction dr.

With the valve construction body 10 shown in the figure, the spring 13 is arranged to be elastically deformable in the axial direction da and in the radial direction dr. This causes an imbalance in the force applied from the spring 13 to the radial direction dr of the spool 11, and a stronger force acts on the spool 11 in a specific radial direction dr. Therefore, when the valve element 11 moves in the axial direction da against the pressing force of the spring 13 and the clearance C is formed between the valve element 11 and the valve seat member 12 (i.e., in the valve-open state), as shown in fig. 2, the valve element 11 is partially separated from the edge portion of the valve seat member 12 (the edge portion E2 in fig. 2) while maintaining a state in which a part of the valve element 11 is in close contact with the edge portion of the valve seat member 12 (the edge portion E1 in fig. 2). In this way, even when the clearance C is formed between the valve element 11 and the valve seat member 12, the valve element 11 is supported by the valve seat member 12, and therefore, the valve element 11 in the valve-open state can be prevented from vibrating.

In particular, since the generation of such vibration of the valve body 11 is prevented by at least one of the structure of the spring 13 and the elastic adjustment member (see reference numeral "30" in fig. 5), it is not necessary to provide a slope surface in another member in order to prevent the vibration of the valve body 11. In addition, when the vibration of the valve body 11 is prevented from occurring due to the structure of the spring 13, the valve structure 10 can be manufactured at low cost without providing any special additional element, and the vibration of the valve body 11 can be directly and efficiently suppressed. Further, when the vibration of the valve body 11 is prevented from being generated by the elastic adjustment member (see reference numeral "30" in fig. 5), the structure of the valve structure 10 in the axial direction da can be prevented from being complicated or enlarged by making the position of the elastic adjustment member in the axial direction da the same as the position of at least a part of the spring 13 in the axial direction da.

Hereinafter, a more specific structural example for preventing the occurrence of vibration of the valve body 11 will be described.

Fig. 3 to 5 are schematic diagrams showing cross-sectional structural examples of the spring 13. Fig. 3 and 4 illustrate the spring 13 in the case of preventing the vibration of the valve body 11 from being generated based on the structure of the spring 13, and fig. 5 illustrates the spring 13 in the case of preventing the vibration of the valve body 11 from being generated based on the elastic adjustment member 30, respectively.

The spring 13 shown in fig. 3 is curved along a curve extending in the axial direction da and in the radial direction dr. When the spring 13 is formed of a compression coil spring As described above, the center axis of the spring 13 (hereinafter, also referred to As "spring center axis") As shown in fig. 3 describes a curve having a curvature other than 0 (zero). Furthermore, the curve may have a single curvature or a plurality of different curvatures. Thereby, the spring 13 can apply the elastic force in the axial direction da and the elastic force in the radial direction dr to the valve body 11. That is, the elastic force exerted by the spring 13 when the spring 13 is compressed in the axial direction da includes the elastic force in the axial direction da and the elastic force in the radial direction dr, and the overall direction of the elastic force of the spring 13 is not parallel to the axial direction da and not parallel to the radial direction dr.

With the spring 13 shown in fig. 4, one end surface S1 thereof in contact with the spool 11 does not extend parallel to the radial direction dr. In this case, the elastic force exerted by the spring 13 includes the elastic force in the axial direction da and the elastic force in the radial direction dr, but the overall direction of such elastic forces is not parallel to the axial direction da and is not parallel to the radial direction dr. Further, the spring center axis As of the spring 13 shown in fig. 4 depicts a straight line and extends in parallel with the axial direction da. However, it is also possible that the one end surface S1 does not extend parallel to the radial direction dr, and the spring center axis As is curved not parallel to the axial direction da.

With the spring 13 shown in fig. 5, the elastic adjustment member 30 restrains a part of the spring 13 to restrict movement of a part of the spring 13 in the axial direction da. More specifically, the elastic adjustment member 30 is fixed to a fixed member such as the valve seat member 12, and fixes only a part of the spring 13 in the axial direction da on one side (i.e., only a part of the radial direction dr; in fig. 5, the lower side) of the spring 13 in the radial direction dr. Since the portion of the spring 13 fixed by the elastic adjustment member 30 is substantially prevented from moving in the axial direction da, it does not substantially exhibit elasticity and does not exert an elastic force (pressing force). This causes the spring 13 to generate an imbalance in the elastic force applied to the spool 11 in the radial direction dr. Therefore, in this case, the elastic force exerted by the spring 13 includes the elastic force in the axial direction da and the elastic force in the radial direction dr, but the overall direction of such elastic force is not parallel to the axial direction da and not parallel to the radial direction dr. Further, the elasticity adjusting member 30 may not necessarily completely fix a part of the spring 13, and may be configured to reduce the elasticity in the axial direction da of the spring 13 to make the contacted part of the spring 13 difficult to deform. In addition, although the elasticity of the elastic adjustment member 30 is not limited, it is preferable that the elastic modulus of the elastic adjustment member 30 is larger than the elastic modulus of the spring 13 in the axial direction da from the viewpoint of restricting the movement of the spring 13.

Further, the orientation and shape of the one end surface S1 and the other end surface S2 of the spring 13 can be determined appropriately. For example, the other end surface S2 of the spring 13, which is provided on the opposite side of the one end surface S1 that contacts the valve body 11, may extend parallel to the radial direction dr. In this case, the support surface of the member that supports the other end surface S2 of the spring 13 is formed parallel to the radial direction dr, and thus the spring 13 can be stably supported. For example, in the spring 13 shown in fig. 3 and 5, the one end surface S1 that contacts the spool 11 may or may not extend parallel to the radial direction dr. When the one end surface S1 extends parallel to the radial direction dr, the entire one end surface S1 of the spring 13 can be stably brought into contact with the valve body 11 (for example, the valve body 11 shown in fig. 1), and a pressing force (elastic force) can be stably applied from the spring 13 to the valve body 11.

Next, an application example of the valve structure 10 will be described.

The above-described valve structure 10 (particularly, the configuration of the spring 13, the elastic regulation member 30) can be applied to various types of valves, and applicable valves thereof are not limited. For example, the valve structure 10 can be applied to a pressure control valve such as a relief valve or a pressure reducing valve, or another valve such as a check valve. An example of a relief valve to which the valve structure 10 described above can be applied will be described below.

Fig. 6 is a longitudinal sectional side view of relief valve 50.

The relief valve 50 shown in fig. 6 is a balanced piston type relief valve, and includes body members 110 and 112 constituting a valve main body. The valve body incorporates an anti-cavitation valve 114, a pressure regulating valve body 115, a piston 116, a pilot valve body 118, a plug (spring housing member) 119, and a pilot spring (compression coil spring) 120.

The body member 110 has a small diameter portion 110a on the front end side (left side in fig. 6) and a large diameter portion 110b on the rear end side (right side in fig. 6), and the body member 112 also has a small diameter portion 112a on the front end side and a large diameter portion 112b on the rear end side. The inner peripheral surface of the large diameter portion 110b of the body member 110 and the outer peripheral surface of the small diameter portion 112a of the body member 112 are connected by a screw structure, and a seal member 122 is provided between the large diameter portion 110b and the small diameter portion 112 a. The outer peripheral surface of the small diameter portion 110a of the body member 110 is connected to the threaded hole of the directional control valve 150 by a screw structure. Further, a seal member 138 is disposed between the small diameter portion 110a and the directional control valve 150.

A seat portion (valve seat member) 112s having a smaller diameter than the small diameter portion 112a extends from the small diameter portion 112a of the main body member 112 toward the distal end side, and a valve hole (working fluid flow passage) 112c having a small diameter is formed on the central axis of the seat portion 112 s. The rear end (right end in fig. 6) opening peripheral edge of the valve hole 112c is chamfered in a tapered shape, thereby forming a valve seat 113. Further, a communication port 112d for communicating the inside and outside of the main body member 112 in the radial direction dr is formed in a portion near the boundary between the seat portion 112s and the small diameter portion 112 a.

The cavitation prevention valve 114 has a small diameter portion 114a on the front end side and a large diameter portion 114b on the rear end side, and a stepped portion 114e is provided between the small diameter portion 114a and the large diameter portion 114 b. A primary flow path 135 for the working fluid is formed inside the small diameter portion 114a, and a secondary flow path 136 for the working fluid is formed between the cavitation prevention valve 114 and the main body member 110.

The rear end of the large diameter portion 114b is fitted to the seat portion 112s outside the seat portion 112s, and a seal member 124 is provided between the large diameter portion 114b and the seat portion 112 s. A flow port 114c for the working fluid penetrating the large diameter portion 114b in the radial direction dr is formed in the front portion of the large diameter portion 114 b. The small diameter portion 114a has a tapered end surface, and forms a seal surface 114f that partitions the pump port (primary port) P and the tank port (secondary port) T in the direction control valve 150. The sealing surface 114f is seated on a tapered valve seat 152 formed at the intersection of the ports P, T, thereby defining the port P, T.

A cylindrical pressure regulating valve body 115 is housed in a position forward of the seat 112s so as to be movable in the axial direction da in the large diameter portion 114b of the cavitation prevention valve 114, and a back pressure chamber 126 is formed between the pressure regulating valve body 115 and the seat 112 s. A seal member 123 is provided between the outer peripheral surface of the pressure regulating valve body 115 and the inner peripheral surface of the large diameter portion 114 b.

A tapered surface 115d is formed on the outer peripheral portion of the tip end of the pressure regulating spool 115, and a stepped portion whose position changes in the radial direction dr is formed on the large diameter portion 114b, and the valve seat 114d is constituted by this stepped portion. Since the tapered surface 115d of the pressure regulating valve body 115 is pressed against the valve seat 114d, the flow port 114c is closed by the pressure regulating valve body 115. On the other hand, the tapered surface 115d is separated from the valve seat 114d, whereby the flow port 114c is opened.

The piston 116 includes a main body tube portion 116a, a flange portion 116b, and a poppet pressing shaft portion 116c, which are arranged in this order from the front end side to the rear end side. A pressure receiving chamber 116d that opens forward is formed on the central axis of the main body tube 116a, an orifice 116e is formed in the main body tube 116a, and the back pressure chamber 126 on the inner side and the outer side of the pressure receiving chamber 116d communicate with each other through the orifice 116 e.

The inner diameter of the pressure regulating valve body 115 is smaller in the front portion than in the rear portion, and the main body tube 116a of the piston 116 is inserted into the front portion with substantially no gap. An adjustment spring 128 formed of a compression coil spring is provided between the stepped portion 115a and the flange portion 116b of the piston 116, and the stepped portion 115a is formed at a boundary between an inner surface of a front portion and an inner surface of a rear portion of the pressure regulating valve body 115. The poppet pressing shaft portion 116c is inserted into the valve hole 112c of the seat portion 112s, and a flow passage extending in the axial direction da through which the working fluid can flow is secured between the inner peripheral surface of the valve hole 112c and the outer peripheral surface of the poppet pressing shaft portion 116 c.

The pilot spool 118 includes: a poppet 118a whose cross-sectional diameter gradually decreases toward the front; and a shaft portion 118b extending rearward from a center portion of the poppet 118a in the radial direction dr. The outer peripheral surface of the poppet 118a has a shape capable of contacting the valve seat 113 of the seat 112 s.

The plug 119 is inserted into and fixed to the large diameter portion 112b of the body member 112. Specifically, a male screw formed in the plug 119 is screwed into a female screw formed in the large diameter portion 112 b. The plug 119 is fixed to the large-diameter portion 112b at a desired insertion position by a nut 132 screwed to the external thread of the plug 119, and the elastic force of the pilot spring 120 is adjusted in accordance with the insertion position of the plug 119. Further, a seal member 130 is provided between the front outer peripheral surface of the plug 119 and the inner peripheral surface of the small diameter portion 112 a.

The plug 119 has a spring receiving chamber 134 opened in the front, and the valve chamber is formed by the spring receiving chamber 134 and the space inside the body member 112. The pilot spring 120 is housed in the spring housing chamber 134. The pilot spring 120 is compressed between a rear end surface of the poppet 118a of the pilot valve spool 118 and a rear end surface (rear end surface) of the spring housing chamber 134 in a state of being fitted to the shaft portion 118b outside the shaft portion 118b of the pilot valve spool 118, and the pilot valve spool 118 is pressed forward by an elastic force (compression force) of the pilot spring 120. The conical surface of the poppet 118a is pressed against the valve seat 113, thereby ensuring a closed valve state.

Basically, the inner diameter of the spring housing chamber 134 is set to be larger than the outer diameter of the pilot spring 120, but only the inner diameter of the rear end 134a of the spring housing chamber 134 is set to be substantially equal to the outer diameter of the pilot spring 120. The rear end of pilot spring 120 is inserted into and fixed to rear end portion 134 a.

In the relief valve 50 shown in fig. 6, the tank unit for closing or opening the 1 st connection path 41 between the primary flow path 135 (1 st flow path) and the secondary flow path 136 (2 nd flow path) includes a pressure regulating valve body 115, an anti-cavitation valve 114, and a regulating spring 128. The 1 st connection path 41 is closed by the tapered surface 115d and the valve seat 114d being fitted to each other without a gap, and the 1 st connection path 41 is opened by the tapered surface 115d and the valve seat 114d being at least partially separated from each other. The sub-valve unit that closes or opens the 2 nd connection path 42 between the back pressure chamber 126 (the 3 rd flow path) and the spring housing chamber 134 (the 4 th flow path) includes the pilot spool 118, the body member 112, and the pilot spring 120, and the back pressure chamber 126 (the 3 rd flow path) communicates with the primary side flow path 135 (the 1 st flow path) via the pressure receiving chamber 116d and the orifice 116 e. The 2 nd connection path 42 is closed by causing the poppet 118a and the valve seat 113 to fit each other without a gap, and the 2 nd connection path 42 is opened by causing the poppet 118a and the valve seat 113 to be at least partially separated from each other.

As specific characteristics of the relief valve 50 including the above-described parent valve unit and the child valve unit, for example, japanese patent application laid-open No. 2002-295702 is referred to.

In the relief valve 50 having the above-described configuration, at least one of the parent valve unit and the child valve unit includes the valve body 11, the valve seat member 12, and the pressing portion 14, and thus vibration of the valve body 11 can be effectively prevented when the valve is opened. That is, the spring (specifically, the adjustment spring 128 and/or the pilot spring 120) provided in the pressing portion 14 of the parent valve unit and/or the child valve unit can suppress the vibration of the valve body 11 as described above by applying the elastic force in the axial direction da and the elastic force in the radial direction dr to the valve body 11.

Therefore, for example, the pilot spring 120 is constituted by the spring 13 shown in fig. 3 and 4, or the pilot spring 120 is constituted by the spring 13 shown in fig. 5 and the elastic adjustment member 30, so that vibration in the radial direction dr when the pilot spool 118 is opened can be suppressed. Further, by constituting the adjustment spring 128 by the spring 13 shown in fig. 3 and 4 or constituting the adjustment spring 128 by the spring 13 and the elastic adjustment member 30 shown in fig. 5, it is possible to suppress vibration in the radial direction dr when the valve opening of the pressure regulating valve body 115 is performed.

The present invention is not limited to the above-described embodiments and modifications. For example, various modifications may be applied to the respective elements of the above-described embodiments and modifications, or the embodiments and modifications may be partially combined. The effects of the present invention are not limited to the above-described effects, and specific effects according to specific configurations are exhibited.

For example, in the spring 13 shown in fig. 3, the spring 13 has a curved structure, and the spring 13 may be curved by a member (elastic adjustment member (not shown)) provided separately from the spring 13. The position of the separate member is not particularly limited, but is preferably the same as the position of at least a part of the spring 13 in the axial direction da, and may be provided at a position adjacent to the spring 13 in the radial direction dr, for example, as in the position of the elastic adjustment member 30 shown in fig. 5.

The valve structure 10 described above may be applied to either a pilot type valve or a direct acting type valve.

[ application example ]

The valve structure 10 described above can be mounted on various machines, and particularly, a construction machine such as a hydraulic excavator, and other work machines can be provided with the valve structure 10 described above.

Fig. 7 is a schematic external view showing a typical configuration example of the hydraulic excavator 210. In general, the hydraulic excavator 210 includes: a lower frame 244 provided with crawler belts; an upper frame 245 provided to be rotatable with respect to the lower frame 244; a boom 247 attached to the upper frame 245; an arm 248 attached to the boom 247; and a bucket 249 attached to the arm 248. Hydraulic cylinders 267, 268, and 269 serving as actuators are hydraulic cylinders for a boom, an arm, and a bucket, and drive a boom 247, an arm 248, and a bucket 249, respectively. A rotational driving force from the swing motor 246 is transmitted to the upper frame 245 to swing the upper frame 245 by the swing motor 246. The rotational driving force from the travel motor 251 is transmitted to the crawler belt of the lower frame 244, and the crawler belt is driven by the travel motor 251 to travel the excavator 210.

In the hydraulic excavator 210, for example, a valve including the valve structure 10 described above may be provided at an appropriate position in an oil passage included in or connected to the hydraulic cylinders 267, 268, 269, the swing motor 246, and/or the traveling motor 251.