JP2006194334A - Relief valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relief valve having a reduced size with a less number of components and reduced cost to achieve simplified construction. <P>SOLUTION: A valve body 49 consists of a retainer 35 threaded to a casing 31 and a plug 43 threaded to the retainer 35. A piston 52 is provided adjacent to the plug 43 and slidably fitted through the retainer 35. A poppet valve element 68 is slidably provided on the retainer 35. The poppet valve element 68 has one end at which a conical portion 62 is provided for communicating an inlet passage 40 and an outlet passage 42 in the retainer 35 with each other and shutting one off the other, and the other end which is supported by the plug 43 and the piston 52. A pressure control spring member 76 is provided between the plug 43 and an adjusting bolt 72 threaded to the plug 43. A hydraulic pressure chamber 73 consists of the plug 43, the adjusting bolt 72, and the poppet valve element 68. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a relief valve for a hydraulic motor for driving a turning device for a construction machine, and more particularly to an improvement of a relief valve that realizes a reduction in size, weight and stability of performance.

  Conventionally, this type of relief valve is disposed inside the valve body 6 so as to be movable by a predetermined distance in the axial direction, and opens and closes the communication path between the pressure fluid supply side and the relief side, and the valve body 6 The movable spring receiving member 13 disposed on the inner periphery of the movable spring 13 and movable in the axial direction by a predetermined distance is interposed between one end of the movable receiving member 13 and one end of the plunger 9 so that the plunger 9 is on one end side. And a main spring 14 for urging the movable spring receiving member 13 toward the other end, and an inner periphery of the movable spring receiving member 13 which is integrally connected to the plunger 9 and extends to the other end in the axial direction. A rod 8 slidably penetrating the surface is provided.

Furthermore, the liquid chamber 20 is provided on the other end surface of the movable spring receiving member 13, and the rod 8 is formed with a hole 8a for introducing a part of the supply-side pressure liquid acting on the plunger 9 into the liquid chamber 20, In the relief valve for adjusting the set pressure by compressing the main spring 14 via the movable spring receiving member 13 by the hydraulic pressure of the liquid chamber 20, the liquid chamber 20 is engaged with the rod 8 and the rod The adjusting spring 24 for urging the plunger 9 toward the closing side in the axial direction via the shaft 8 is retracted, and a variable means 25 for varying the urging force of the adjusting spring 24 is provided so as to be operable from the outside of the valve body 6. 8 has a closed space 23 in which a bush 21 is mounted at the other end and is surrounded by the rod 8 and the bush 21, and the hole 8 a of the rod 8 communicates with the closed space 23. Drill the rod 8 along the radial direction Communicates with the liquid chamber 20 through the pores 8b that is (for example, see Patent Document 1).
Japanese Utility Model Publication No. 1-77174 (FIG. 1)

However, the relief valve described in Patent Document 1 requires the plug 5, the rod 8, the adjustment bolt 19, the bush 21, and the retainer 22 in order to form a closed space 23 for pressure adjustment and hunting prevention. . For this reason, the relief valve becomes longer in the axial direction, making it difficult to attach to the actual machine. Furthermore, since the number of parts increases, it causes a cost increase.
Further, in order to increase the stroke length of the movable spring receiving member 13, an annular gap is used in the throttle mechanism, so that the flow rate of the pressurized liquid passing through the throttle changes depending on the oil temperature (viscosity of the pressurized liquid) and is movable. The moving speed of the spring receiving member 13 changes. Therefore, when the oil temperature changes, the hydraulic motor starts and the feeling during braking changes, which makes it very difficult to use.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a relief valve that can be reduced in size by reducing the number of parts in order to simplify the structure and reduce the cost. And

To achieve the above object, the present invention according to claim 1 is a movable body that is disposed in the valve body so as to be movable by a predetermined distance in the axial direction and opens and closes the communication path between the pressure oil supply side and the discharge side. When,
A piston member disposed between an outer periphery of the movable body and an inner periphery of the valve main body and displaceable in an axial direction;
A main spring member that is provided between the piston member and the movable body and biases the movable body toward one end and the piston member toward the other end;
A hydraulic chamber composed of the valve body, the movable body, and an adjustment bolt member screwed to the movable body;
An adjustment spring member provided in the hydraulic pressure chamber and biasing the movable body in the axial direction;
Provided,
A hole is formed in the movable body for introducing a part of the supply-side pressure oil acting on one end surface of the movable body into the hydraulic chamber, and the hydraulic oil in the hydraulic chamber passes the adjustment spring member through the adjustment spring member. In a relief valve that adjusts the set pressure by compressing the main spring member,
A plurality of orifice mechanisms for extending the movement time of the piston member are provided in series in the valve body.
According to the first aspect of the present invention, since the hydraulic chamber can be constituted by three points of the plug, the poppet valve body, and the adjusting bolt member, the number of parts is small, and the length in the axial direction can be shortened to be inexpensive. .
According to a second aspect of the present invention, the orifice mechanism includes a second orifice oriented in the diametrical direction and a third orifice oriented in the axial direction, and is arranged in series. An effect can be acquired and it is suitable.

In the present invention, since the hydraulic chamber is composed of three points of the plug, the poppet valve body and the adjusting bolt member, the number of parts is small, and the second orifice is provided in the diameter direction in the throttle in order to increase the moving time of the piston member. Since the third orifice is provided in the axial direction and arranged in series, the length in the axial direction can be shortened and the cost can be reduced.
Further, since the orifice is used for the throttle, the change in performance with respect to the change in the oil temperature is small, and the change in feeling at the start brake of the hydraulic motor with respect to the change in the oil temperature can be reduced.
In addition, it is possible to change the performance of the relief valve by changing the orifice diameter provided in the valve body, and it is easy to tune the performance in the actual machine without replacing main parts.

A relief valve according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a schematic structure of a relief valve 30 according to an embodiment of the present invention.
As shown in FIG. 1, reference numeral 31 denotes a casing, and a supply passage 32 and a discharge passage 33 that are communication passages are formed in the casing 31. One end side (left side in FIG. 1) of the cylindrical retainer 35 is inserted into the hole 34 formed in the casing 31 and is screwed to the casing 31 via a screw mechanism 36. Yes. In this case, the retainer 35 is positioned in the axial direction of the retainer 35 by the stepped portion 37a in which the cylindrical portion 38 is formed abutting against the casing 31. Further, a cylindrical portion 39 that forms a stepped portion 37b larger than the stepped portion 37a is formed on the other end side (right side in FIG. 1) from the substantially central portion of the retainer 35.

An inlet passage 40 having a substantially circular cross section that communicates with the supply passage 32 is formed at one end of the retainer 35 (left end in FIG. 1). The inlet passage 40 is provided with a circular hole 41 that is larger in cross section than the inlet passage 40, and an outlet passage 42 that communicates with the discharge passage 33 is appropriately provided in the circumferential direction in the hole 41. A plurality (two are displayed in FIG. 1) are provided at a small interval.
On the other hand, the outer periphery of one end side of the substantially cylindrical plug 43 is screwed to the inner periphery of the other end of the retainer 35. In this case, the plug 43 is screwed to the retainer 35 by the screw means 44, and the stepped portion 46 of the large diameter portion 45 at the substantially central portion of the plug 43 is brought into contact with the side wall surface 47 of the retainer 35. Is fixed to a predetermined position of the retainer 35. An internal thread 48 is formed on the inner periphery of one end of the plug 43. The casing 31, the retainer 35 and the plug 43 constitute a valve body 49. The other end side (left side in FIG. 1) of the plug 43, that is, the large diameter portion 45 is fitted into a hole 51 formed in the retainer 35. Further, a piston (piston member) 52 is slidably inserted into the hole 51, and the side wall surface 54 of the piston 52 is brought into contact with the end surface 88 of the large-diameter portion 45 of the plug 43 by the elastic force of the spring member 53. Abutted. Note that annular recesses 56 and 57 are formed in the side wall surfaces 54 and 55 of the piston 52.

  A substantially cylindrical poppet 58 is disposed on the axial center of the retainer 35, and axial holes 59, 60 are formed on the axial center of the poppet 58. The first orifice 61 communicates. One end of the poppet 58 is formed as a conical portion 62, the seat surface 63 is defined by engaging with the inlet passage 40, and the other end (right side in FIG. 1) from the substantially central portion is the piston 52. And it is inserted in the plug 43 so that sliding is possible. When the conical portion 62 of the poppet 58 is engaged with the inlet passage 40, the outer peripheral surface of the cylindrical portion 64 is fitted into the inner peripheral surface of the hole 41 of the retainer 35 and guided by the hole 41, so that the seat surface 63 Is ensured.

The stepped portion 66 formed between the cylindrical portion 64 and the cylindrical portion 65 is fitted with the inner peripheral surface of the spacer 67 on the outer peripheral surface of the cylindrical portion 65. A valve body (movable body) 68 is configured. A spring member 53 wound around the cylindrical portion of the poppet valve body 68 is disposed between the stepped portion 66 of the poppet valve body 68 and the annular portion 57 of the piston 52.
The spring member (main spring member) 53 engages the conical portion 62 of the poppet valve body 68 with the end of the inlet passage 40 to define the seat surface 63, so that the inlet passage 40 and the outlet passage 42 are separated from each other. The space is communicated and disconnected, and the piston 52 is pressed against the plug 43. That is, a cylindrical spring chamber 70 for accommodating the spring member 53 is formed between the inner periphery of the retainer 35 and the outer periphery of the poppet valve body 68, and the spring chamber 70 is discharged through the hole 71. It communicates with the passage 33. A plurality of the holes 71 are formed in the retainer 35 at appropriate intervals in the circumferential direction.

An adjustment bolt (adjustment bolt member) 72 is screwed into the female screw 48 of the plug 43, and a hydraulic pressure chamber 73 is formed by the adjustment bolt 72, the plug 43, and the poppet valve body 68.
The hydraulic pressure chamber 73 is provided with circular projections 74 and 75 projecting axially from one end of the poppet valve body 68 and the adjusting bolt 72. Both ends of a spring member (adjustment spring member) 76 are wound and engaged with one end of the plug 43 and the poppet valve body 68. The spring member 76 is urged against the poppet valve body 68 and the plug 43 by an elastic force. Therefore, the conical portion 62 of the poppet valve body 68 is pressed against the end face of the inlet passage 40 of the valve body 49. Therefore, the pressing force to the poppet valve body 68 due to the elastic force of the spring member 76 can be adjusted by the turning operation of the adjusting bolt 72, and the adjusting bolt 72 and the position of the adjusting bolt 72 are screwed into the adjusting bolt 72. An adjusting means 79 for adjusting the resilience of the spring member 76 is constituted by a nut 77 for fixing the nut and a washer 78 mounted between the nut 77 and the plug 43.

The spring member 53 has one end engaged with the spacer 67 and the other end engaged with the annular recess 57 of the side wall surface 55 of the piston 52.
On the other hand, the second orifice 80 oriented in the diameter direction communicates with the hydraulic chamber 73, and the third orifice 81 oriented in the axial direction communicates with the orifice 80. The second and third orifices 80 and 81 are constituted by a fine hole 82, a guide hole 83, a fine hole 84, and a guide hole 85, respectively. In this case, the second orifice 80 communicates with an annular groove 86 formed on the outer peripheral surface of the large diameter portion 45 of the plug 43. The guide hole 85 of the third orifice 81 communicates with the end surface 88 of the large diameter portion 45 of the plug 42 that engages the side wall surface 54 of the piston 52.

The relief valve 30 according to the embodiment of the present invention is basically constructed as described above. Next, the operation and effect thereof will be described.
Pressure oil supplied from a pressure supply source (not shown) enters the inlet passage 40 from the supply passage 32, acts on the conical portion 62 of the poppet valve body 68, and resists the elastic force of the spring members 53, 76. 68 is displaced in the arrow Y direction. As a result, the pressure oil causes the inlet passage 40 and the outlet passage 42 to communicate with each other by separating the seat surface 63 between the opening end face of the inlet passage 40 of the valve body 49 and the conical portion 62 of the poppet valve body 68 from the inlet passage 40. . Accordingly, the pressure oil is discharged from the supply passage 32 to the discharge passage 33. At this time, the poppet valve body 68 starts to open, the spring force of the spring member 53 is small, and the pressure oil is at a low pressure, for example, the pressure P1, as shown in FIG.

  Next, the pressure oil that has flowed into the inlet passage 40 is supplied to the hydraulic pressure chamber 73 through the hole 59, the first orifice 81, and the hole 60, and passes through the second orifice 80 and the third orifice 81 from the hydraulic pressure chamber 73. After that, it flows into the closed space 87. The pressure oil flowing into the closed space 87 presses the piston 52 in the direction of the arrow X against the elastic force of the spring member 53 and moves it to the slow end. Thereby, the elastic force of the spring member 53 increases, and the maximum amount of pressure oil is discharged to the outlet passage 33 at a high pressure corresponding to this elastic force, for example, the pressure P2 (see FIG. 2).

  According to the relief valve 30 according to the embodiment of the present invention, the hydraulic chamber 73 is configured by the plug 43, the poppet valve body 68, and the adjusting bolt 72, so the number of parts is small and the length in the axial direction is shortened. Can be cheap. As a throttle for extending the moving time of the piston 52, for example, t (see FIG. 2), the plug 43 is formed with the second orifice 80 in the diameter direction and the third orifice 81 in the axial direction. A sufficient throttling effect can be obtained by arranging the orifices 80 and 81 in series to form a structure.

It is a longitudinal section showing a schematic structure of a relief valve concerning an embodiment of the invention. FIG. 2 is a pressure-time diagram showing a relationship between a displacement time by the poppet valve body of FIG. 1 and a relief pressure.

Explanation of symbols

30 Relief valve 31 Casing 35 Retainer 43 Plug 49 Valve body 52 Piston 61, 80, 81 Orifice 68 Poppet valve body 53, 76 Spring member 72 Adjustment bolt

Claims (2)

A movable body that is arranged in the valve body so as to be movable a predetermined distance in the axial direction and opens and closes the communication path between the pressure oil supply side and the discharge side;
A piston member disposed between an outer periphery of the movable body and an inner periphery of the valve main body and displaceable in an axial direction;
A main spring member that is provided between the piston member and the movable body and biases the movable body toward one end and the piston member toward the other end;
A hydraulic chamber composed of the valve body, the movable body, and an adjustment bolt member screwed to the movable body;
An adjustment spring member provided in the hydraulic pressure chamber and biasing the movable body in the axial direction;
Provided,
A hole is formed in the movable body for introducing a part of the supply-side pressure oil acting on one end surface of the movable body into the hydraulic chamber, and the hydraulic oil in the hydraulic chamber passes the adjustment spring member through the adjustment spring member. In a relief valve that adjusts the set pressure by compressing the main spring member,
A relief valve according to claim 1, wherein a plurality of orifice mechanisms for increasing the movement time of the piston member are provided in series in the valve body. The relief valve according to claim 1,
2. The relief valve according to claim 1, wherein the orifice mechanism includes a second orifice oriented in a diameter direction and a third orifice oriented in an axial direction.

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