JP2018053931A - Shockless relief valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shockless relief valve enabling a device to be simplified and its size to become small.SOLUTION: A shockless relief valve 2 acts to shut off or communicate between a high pressure passage 61 and a low pressure passage 62 formed at a main body 60. An annular piston member 77 movably supported in an axial direction by an outer peripheral part of a hollow body 64 divides a slide space 79 into a first oil chamber 81 and a second oil chamber 82. The high pressure passage 61 is communicated with a cavity part 67 through an open hole 73. The hollow body 64 has a second orifice part 76 to cause the cavity part 67 and the first oil chamber 81. The second oil chamber 82 is communicated with the low pressure passage 62. The main body 60 has a shoulder part 85 defining a part of the second oil chamber 82. The piston member 77 moves in an axial direction at the slide space 79 in response to a difference of pressure of hydraulic oil in the first oil chamber 81 and pressure of hydraulic oil in the second oil chamber 82. Under a state in which the piston member 77 is contacted with the shoulder part 85, a part between the first oil chamber 81 and the second oil chamber 82 is shut off.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a shockless relief valve applicable to a hydraulic motor for driving a construction vehicle such as a crawler vehicle.

  The shockless relief valve is a relief valve that can apply an appropriate braking force while alleviating an impact that may occur when applying a braking force to a drive mechanism such as a motor. This shockless relief valve is preferably applied to, for example, a hydraulic motor that continues to rotate with inertia during braking.

  The shockless relief valve disclosed in Patent Literature 1 includes a first communication valve and a second communication valve provided between the first load passage and the second load passage, and a space between the first communication valve and the second communication valve. And an accumulator provided. The accumulator of the shockless relief valve includes a delay passage provided in the piston so as to connect the first cylinder chamber and the second cylinder chamber separated via the piston, and the first cylinder chamber and the second cylinder chamber. And have. The shockless time is extended by arranging a throttle in the delay passage.

JP 2012-127477 A

  When using the shockless relief valve disclosed in Patent Document 1, it is necessary to install a first communication valve, a second communication valve, and an accumulator between the first load passage and the second load passage. It is required to secure a large installation space. Moreover, it is necessary to form an oil passage that connects the first communication valve, the second communication valve, and the accumulator so that the pressure oil can flow appropriately between the first communication valve, the second communication valve, and the accumulator. is there. Further, the accumulator needs to appropriately form the first cylinder chamber, the second cylinder chamber, the delay passage, and the throttle, and is required to process the piston that defines these elements with high accuracy.

  Therefore, when using the shockless relief valve disclosed in Patent Document 1, the device tends to be complicated and large.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a shockless relief valve capable of simplifying and downsizing the apparatus.

  One aspect of the present invention is a shockless relief valve that blocks or communicates between a high-pressure passage and a low-pressure passage formed in a main body, the hollow body having a hollow portion, and at least a part of the hollow portion A through hole communicating with the high-pressure passage and the cavity, and a first aperture for locally reducing the cross-sectional area of the through hole And an annular piston member that is supported by the outer peripheral portion of the hollow body so as to be movable in the axial direction, and is arranged in a slide space formed between the main body and the hollow body, and the slide space Is divided into a first oil chamber formed on one side of the piston member with respect to the axial direction and a second oil chamber formed on the other side of the piston member, and the poppet has a high pressure Aisle pressure oil and low When the pressure difference with the pressure oil in the passage is larger than the first value, it is arranged at a position where the high pressure passage and the low pressure passage communicate with each other. When the pressure difference is less than the first value, the high pressure passage and the low pressure passage are arranged. The hollow body has a second throttle portion that communicates the cavity and the first oil chamber, the second oil chamber communicates with the low-pressure passage, and the main body has the second A shoulder portion defining a part of the oil chamber, the shoulder portion contacting the piston member to stop the movement of the piston member to the other side, and the piston member is formed of the pressure oil in the first oil chamber. The slide space is moved in the axial direction according to the difference between the pressure and the pressure oil pressure in the second oil chamber, and the first oil chamber and the second oil chamber are disconnected when the piston member is in contact with the shoulder. The related shockless relief valve.

  The piston member has at least one throttle hole. The at least one throttle hole communicates the first oil chamber and the second oil chamber when the piston member is separated from the shoulder portion, and the piston member is the shoulder portion. In a state where the first oil chamber and the second oil chamber are in contact with each other, the first oil chamber and the second oil chamber may not be communicated with each other.

  The shockless relief valve includes an elastic member disposed in the cavity, and a pressure adjusting member that is provided between the poppet and the elastic member, and that can adjust the force applied to the poppet from the elastic member by changing the thickness. Further, it may be provided.

  When the pressure oil pressure in the high pressure passage is greater than the pressure oil pressure in the low pressure passage and the piston member is away from the shoulder, the pressure oil existing between the high pressure passage and the first throttle portion in the through hole. Is higher than the pressure of the pressure oil in the cavity, the pressure of the pressure oil in the cavity is greater than the pressure of the pressure oil in the first oil chamber, and the pressure of the pressure oil in the first oil chamber is the pressure of the second oil chamber. It may be larger than the pressure of the pressure oil.

  When the pressure oil pressure in the high pressure passage is greater than the pressure oil pressure in the low pressure passage and the piston member is in contact with the shoulder, the pressure oil in the through hole, the pressure oil in the cavity, and the first oil chamber The pressure oil may have the same pressure.

  When the pressure oil pressure in the high pressure passage is greater than the pressure oil pressure in the low pressure passage and the piston member is away from the shoulder, the pressure oil pressure in the cavity portion is the same as the pressure oil pressure in the high pressure passage. The pressure oil pressure may be larger than the pressure oil pressure in the cavity portion in a state where the piston member is in contact with the shoulder portion.

  According to the present invention, by combining a poppet at least a part of which is disposed in the hollow portion of the hollow body and a piston member provided on the outer peripheral portion of the hollow body, a shockless device that can simplify and reduce the size of the device. A relief valve can be provided.

FIG. 1 is a circuit diagram illustrating an example of a hydraulic motor. FIG. 2 is a cross-sectional view showing an example of a shockless relief valve. FIG. 3 is a cross-sectional view showing an example of a piston member. FIG. 4 is a cross-sectional view showing another example of the piston member. FIG. 5 is a cross-sectional view for explaining the operation of the shockless relief valve. FIG. 6 is a cross-sectional view for explaining the operation of the shockless relief valve.

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

  The shockless relief valve described below can be applied to, for example, a traveling hydraulic motor that drives a construction vehicle such as a hydraulic excavator. Generally, oil (also referred to as “pressure oil”) is used as a fluid for operating the traveling hydraulic motor, but the types of components of the fluid that can be controlled by the shockless relief valve are not particularly limited.

[Hydraulic motor]
FIG. 1 is a circuit diagram illustrating an example of a hydraulic motor 100.

  The hydraulic motor 100 includes a motor mechanism 1, a counter balance valve 3, a shockless relief valve 2, 2 ′, and a high / low speed switching valve 4 (two speed switching valve) for switching the operation state between the low speed mode and the high speed mode. ), A shuttle valve 5, a first load passage 51, and a second load passage 52.

  The hydraulic motor 100 is connected to a direction switching valve 101 that controls supply and discharge of pressure oil. A pump 104 for supplying pressure oil to the hydraulic motor 100 is connected to the direction switching valve 101. The direction switching valve 101 is a three-position valve, and is switched to the first switching position 101a when the motor mechanism 1 is rotated forward (or reversely rotated), and when the motor mechanism 1 is rotated reversely (or forwardly rotated). When the motor mechanism 1 is stopped, the position is switched to the neutral position 101b.

  The hydraulic motor 100 is also connected to a pilot pump 105 that supplies pilot pressure oil to the high / low speed switching valve 4 and a speed reducer 103. The motor mechanism 1 and the direction switching valve 101 are connected to each other via the first load passage 51 and the second load passage 52.

[Variable speed mechanism]
The hydraulic motor 100 includes a speed variable mechanism for switching the operation state between the low speed mode and the high speed mode. The speed variable mechanism includes the tilt cylinder 35 and the high / low speed switching valve 4 (two speed switching valve). ) And the shuttle valve 5.

[Shockless relief valve]
The shockless relief valves 2, 2 ′ are provided between the first load passage 51 and the second load passage 52. Each of the shockless relief valves 2, 2 ′ has a first load passage when the pressure difference between the pressure oil in the first load passage 51 and the pressure oil in the second load passage 52 is greater than a predetermined value. 51 is a valve formed so that pressure oil flows from a high pressure passage (high pressure passage) to a low pressure passage (low pressure passage) by communicating 51 and the second load passage 52. The first load passage 51 may be a passage with high hydraulic pressure (high pressure passage) and the second load passage 52 may be a passage with low hydraulic pressure (low pressure passage). Conversely, the second load passage 52 is hydraulic. In some cases, the first load passage 51 becomes a low oil pressure passage (low pressure passage).

  In the example shown in FIG. 1, the left shockless relief valve 2 and the right shockless relief valve 2 ′ have basically the same structure, but the left shockless relief valve 2 is for forward rotation, The shockless relief valve 2 ′ is for reverse rotation. That is, when the motor mechanism 1 stops from the forward rotating state, the left shockless relief valve 2 performs a shockless function, and when the motor mechanism 1 stops from the reverse rotating state, the right side The shockless relief valve 2 'performs a shockless function. In addition, when the motor mechanism 1 stops from the state of normal rotation, the first load passage 51 becomes a high pressure passage described later, and the second load passage 52 becomes a low pressure passage described later. On the other hand, when the motor mechanism 1 is stopped from the reverse rotation state, the second load passage 52 becomes a high pressure passage described later, and the first load passage 51 becomes a low pressure passage described later.

  In the following description of the structure of the shockless relief valve with reference to FIG. 2 to FIG. 6, it is assumed that the motor mechanism 1 stops from the state of normal rotation, and in particular, the left shockless relief for normal rotation. Attention is focused on valve 2. However, when the motor mechanism 1 is stopped from the reverse rotation state, the same operation and effect are shown. The reverse rotation right shockless relief valve 2 'is also the same as the forward rotation left shockless relief valve 2. It operates in the same way.

[Shockless relief valve structure]
FIG. 2 is a cross-sectional view showing an example of the shockless relief valve 2. FIG. 2 illustrates the shockless relief valve 2 in the case where the first load passage 51 is the high pressure passage 61 and the second load passage 52 is the low pressure passage 62.

  The shockless relief valve 2 is a relief valve that blocks or communicates between the high-pressure passage 61 and the low-pressure passage 62 formed in the main body 60, and includes a hollow body 64, a poppet 70, a piston member 77, and a pedestal portion. 69.

  The hollow body 64 includes a hollow main body 65 and a hollow plug portion 66. The hollow main body 65 is inserted into a hole provided in the main body 60. The hollow plug portion 66 is disposed so as to cover the hollow main body 65 inserted into the hole portion of the main body 60 and blocks the inside of the hole portion from the outside. Each of the hollow main body 65 and the hollow plug portion 66 is formed in a hollow shape and has a hollow portion 67 inside. The hollow main body 65 is fitted in the hollow plug portion 66. The hollow portion 67 formed in the hollow main body 65 is connected to the hollow portion 67 formed in the hollow plug portion 66, and an integral hollow portion 67 is formed by both the hollow main body 65 and the hollow plug portion 66.

  At least a part of the poppet 70 (all in the example shown in FIG. 2) is disposed in the hollow portion 67, and is moved in the axial direction (see symbols “D1” and “D2” shown in FIG. Supported as possible. The poppet 70 has a through hole 73 and a first throttle portion 75. The through hole 73 communicates the high pressure passage 61 and the cavity portion 67, and the pressure oil from the high pressure passage 61 can flow into the cavity portion 67 through the through hole 73. The first restricting portion 75 locally reduces the cross-sectional area of the through-hole 73 to restrict the flow passage area, and a flow passage having a diameter of, for example, 1 mm or less is formed by the first restricting portion 75. The pressure oil that has flowed into the through-hole 73 from the high-pressure passage 61 flows into the cavity portion 67 through the flow path formed by the first throttle portion 75.

  An elastic member 89 formed of a spring or the like is disposed in the hollow portion 67 of the hollow body 64 (that is, the hollow main body 65 and the hollow plug portion 66). One end of the elastic member 89 is seated on the bottom of the hollow plug portion 66, and the other end of the elastic member 89 is seated on the pressure adjusting member 91 attached to the poppet 70. The elastic member 89 is disposed in a compressed state between the bottom portion of the hollow plug portion 66 and the pressure adjusting member 91, and applies an elastic force in the first direction D1 to the bottom portion of the hollow plug portion 66 and in the second direction. The elastic force to D2 is applied to the pressure adjusting member 91 and the poppet 70. Therefore, in order to move the poppet 70 in the first direction D1, it is necessary to apply a force in the first direction D1 against the elastic force of the elastic member 89, and the poppet 70 moves in the first direction D1. As this occurs, the elastic force provided by the elastic member 89 increases. The force applied from the elastic member 89 to the poppet 70 can be adjusted by changing the thickness of the pressure adjusting member 91 provided between the poppet 70 and the elastic member 89.

  The hollow main body 65 further includes a second throttle portion 76 that communicates the cavity portion 67 and the first oil chamber 81. Accordingly, the first oil chamber 81 communicates with the high-pressure passage 61 via the second throttle portion 76, the cavity portion 67 and the through hole 73.

  The annular piston member 77 is supported by the outer peripheral portion of the hollow main body 65 so as to be movable in the axial direction, and is slidably provided on the outer peripheral surface of the hollow main body 65. The piston member 77 is disposed in a slide space 79 formed between the main body 60 and the hollow main body 65. The piston member 77 includes a first oil chamber 81 formed on one side of the slide space 79 with respect to the axial direction in the axial direction (the first direction D1 side (that is, the right side in FIG. 2)) and the piston member 77. It is divided into a second oil chamber 82 formed on the other side (second direction D2 side (that is, the left side in FIG. 2)). The piston member 77 is in contact with the hollow main body 65 and the main body 60 that define the slide space 79, and pressure oil cannot basically flow through the portions where the piston member 77 is in contact with each of the hollow main body 65 and the main body 60.

  The main body 60 has a shoulder 85 that defines a part of the second oil chamber 82. The shoulder 85 comes into contact with the piston member 77 to stop the movement of the piston member 77 in the other side (that is, the second direction D2). That is, the movement of the piston member 77 in the slide space 79 in the second direction D <b> 2 is limited by the shoulder portion 85. On the other hand, the movement of the piston member 77 in the first direction D <b> 1 in the slide space 79 is limited by the hollow plug portion 66. A gap is formed between the shoulder 85 and the hollow body 65, and the slide space 79 (particularly the second oil chamber 82) communicates with the low pressure passage 62 via the gap, and the low pressure passage 62 and the second oil are communicated. Pressure oil can freely move to and from the chamber 82.

  FIG. 3 is a cross-sectional view showing an example of the piston member 77. The piston member 77 has at least one throttle hole 87 (one groove-like throttle hole 87 in the example shown in FIG. 3). The throttle hole 87 is provided so as to penetrate the piston member 77 in the axial direction, and is a hole for communicating the first oil chamber 81 and the second oil chamber 82 described above. The throttle hole 87 connects the first oil chamber 81 and the second oil chamber 82 to form a pressure oil flow path, and also serves as a throttle. Therefore, the flow path area of the throttle hole 87 is very small, and a flow path having a diameter of, for example, 1 mm or less is constituted by the throttle hole 87.

  Further, the throttle hole 87 is provided radially outside the inner peripheral position of the shoulder portion 85 represented by the symbol “A” in FIG. 3, and when the piston member 77 is pressed against the shoulder portion 85, the throttle hole 87. Is closed by the shoulder 85. That is, the throttle hole 87 allows the first oil chamber 81 and the second oil chamber 82 to communicate with each other when the piston member 77 is away from the shoulder portion 85. On the other hand, in a state where the piston member 77 is in contact with the shoulder portion 85, the first throttle portion 75 is blocked by the shoulder portion 85, and the first throttle portion 75 connects the first oil chamber 81 and the second oil chamber 82. Do not communicate. As described above, in the state where the piston member 77 is separated from the shoulder portion 85, the pressure oil can be circulated between the first oil chamber 81 and the second oil chamber 82 through the throttle hole 87. In a state where 77 is in contact with the shoulder 85, the pressure oil basically does not flow between the first oil chamber 81 and the second oil chamber 82.

  The shape of the throttle hole 87 is not particularly limited. Although FIG. 3 shows a throttle hole 87 formed in a groove shape, the throttle hole 87 may be formed in a hole shape having a circular cross section as shown in FIG. Further, the piston member 77 may have a plurality of throttle holes 87. However, all the throttle holes 87 are provided on the radially outer side than the inner peripheral position of the shoulder portion 85 (see reference numeral “A” in FIGS. 3 and 4). Thus, when the piston member 77 is away from the shoulder portion 85, the first oil chamber 81 and the second oil chamber 82 are communicated with each other through the throttle hole 87, and the piston member 77 is in contact with the shoulder portion 85. In the state, the throttle hole 87 is closed by the shoulder 85, and the first oil chamber 81 and the second oil chamber 82 are blocked.

  As described above, the piston member 77 moves the slide space 79 surrounded by the hollow main body 65, the hollow plug portion 66, and the main body 60 (including the shoulder portion 85) into the pressure oil pressure of the first oil chamber 81 and the second oil chamber 82. It slides in the axial direction according to the pressure oil pressure. That is, the piston member 77 moves in the slide space 79 in the axial direction according to the difference between the pressure oil pressure in the first oil chamber 81 and the pressure oil pressure in the second oil chamber 82.

[Operation of shockless relief valve]
Next, the operation of the shockless relief valve 2 will be described. First, the operation of the shockless relief valve 2 as a normal relief valve will be described.

  When the pressure difference between the pressure oil in the high pressure passage 61 and the pressure oil in the low pressure passage 62 is larger than the first value T1, the poppet 70 is disposed at a position where the high pressure passage 61 and the low pressure passage 62 are communicated. On the other hand, when the pressure difference between the pressure oil in the high pressure passage 61 and the pressure oil in the low pressure passage 62 is equal to or less than the first value T1, the poppet 70 is disposed at a position where the high pressure passage 61 and the low pressure passage 62 are blocked. The That is, when the pressure difference Pd between the pressure oil in the high pressure passage 61 and the pressure oil in the low pressure passage 62 is relatively small and equal to or less than the first value T1 (that is, when “Pd ≦ T1” is satisfied), the poppet 70 It is pushed by the elastic member 89 and is seated on the pedestal 69 without any gap. Thereby, the flow path between the high pressure passage 61 and the low pressure passage 62 is blocked by the pedestal 69 and the poppet 70. On the other hand, when the pressure difference Pd between the pressure oil in the high pressure passage 61 and the pressure oil in the low pressure passage 62 is relatively large and becomes larger than the first value T1 (that is, when “Pd> T1” is satisfied). The poppet 70 is pushed away from the pedestal 69 by the pressure oil from the high pressure passage 61. As a result, the high pressure passage 61 and the low pressure passage 62 are communicated with each other via a flow path formed between the pedestal 69 and the poppet 70, and pressure oil flows from the high pressure passage 61 into the low pressure passage 62.

  The first value T1 here can be an arbitrary value, and may be zero (0), for example. In this case, at the timing when the pressure oil pressure in the high pressure passage 61 (first load passage 51 in this example) exceeds the pressure oil pressure in the low pressure passage 62 (second load passage 52 in this example), the poppet 70 The pressure oil flows away from the pedestal 69 and flows into the low pressure passage 62 from the high pressure passage 61.

  Next, shockless braking performed by the shockless relief valve 2 will be described.

  5 and 6 are cross-sectional views for explaining the operation of the shockless relief valve 2.

  While the pressure difference between the pressure oil in the high pressure passage 61 and the pressure oil in the low pressure passage 62 is zero (0) or very small, the poppet 70 is seated on the pedestal 69 as shown in FIG. The connection between 61 and the low pressure passage 62 is blocked. During the forward rotation of the motor mechanism 1, the pressure oil in the second load passage 52 is higher in pressure than the pressure oil in the first load passage 51. Therefore, while the motor mechanism 1 is rotating forward, the pressure oil in the second oil chamber 82 communicating with the second load passage 52 is more than the pressure oil in the first oil chamber 81 communicating with the first load passage 51. The pressure is large, and the piston member 77 receives a force from the second oil chamber 82 toward the first oil chamber 81 (a force toward the right side in FIGS. 5 and 6). For this reason, immediately after the motor mechanism 1 is stopped from the state of normal rotation, the piston member 77 is spaced apart from the shoulder portion 85 in the slide space 79 and is disposed at a position close to the hollow plug portion 66.

  On the other hand, when the pressure oil pressure in the high-pressure passage 61 becomes larger than the pressure oil pressure in the low-pressure passage 62 and the pressure difference becomes larger than the first value T1, the poppet 70 has a pedestal portion as shown in FIG. The pressure oil flows from the high-pressure passage 61 into the low-pressure passage 62 via a flow passage that is separated from the poppet 70 and formed between the poppet 70 and the pedestal 69.

  In this case, the pressure oil also flows into the through hole 73 from the high pressure passage 61. The pressure oil that has flowed into the through-hole 73 flows into the cavity portion 67 through the flow passage whose flow passage area is narrowed by the first restricting portion 75. Then, the pressure oil in the cavity 67 flows into the first oil chamber 81 via the second throttle portion 76. Note that pressure loss occurs in the pressure oil passing through each of the first throttle portion 75 and the second throttle portion 76, and there is a pressure difference between the pressure oil before and after each of the first throttle portion 75 and the second throttle portion 76. Exists.

  On the other hand, the piston member 77 moves in the slide space 79 in the axial direction according to the pressure difference between the pressure oil in the first oil chamber 81 and the pressure oil in the second oil chamber 82, and in particular, the first oil chamber 81. When the pressure P3 of the pressure oil is larger than the pressure P4 of the pressure oil in the second oil chamber 82, the pressure oil moves in the second direction D2. Therefore, the pressure oil in the high pressure passage 61 having a pressure higher than that of the pressure oil in the low pressure passage 62 flows into the first oil chamber 81 through the through hole 73, the cavity portion 67 and the second throttle portion 76, and the first oil chamber 81 When the pressure oil pressure P3 is larger than the pressure oil pressure P4 in the second oil chamber 82, the piston member 77 moves in the second direction D2 toward the shoulder 85, and the second oil chamber 82 gradually increases. It is narrowed to.

  If the pressure P3 of the pressure oil in the first oil chamber 81 is larger than the pressure P4 of the pressure oil in the second oil chamber 82, the first oil is passed through the throttle hole 87 formed in the piston member 77. Pressure oil flows from the chamber 81 into the second oil chamber 82. As a result, the pressure difference between the pressure oil pressure P 3 in the first oil chamber 81 and the pressure oil pressure P 4 in the second oil chamber 82 becomes smaller than when the throttle hole 87 is not formed in the piston member 77. Therefore, the moving speed of the piston member 77 in the second direction D2 becomes slow, and the time until the piston member 77 contacts the shoulder 85 can be increased.

  Thus, in a state where the pressure oil pressure in the high pressure passage 61 is greater than the pressure oil pressure in the low pressure passage 62 and the piston member 77 is separated from the shoulder portion 85, the high pressure passage 61 and the first throttle in the through hole 73. The pressure P1 of the pressure oil existing between the portion 75 and the pressure oil P2 of the cavity 67 is larger. Further, the pressure oil pressure P <b> 2 in the cavity 67 is larger than the pressure oil pressure P <b> 3 in the first oil chamber 81. The pressure oil pressure P3 in the first oil chamber 81 is larger than the pressure oil pressure P4 in the second oil chamber 82.

  On the other hand, when the piston member 77 comes into contact with the shoulder 85 as shown in FIG. 6, the throttle hole 87 is blocked by the shoulder 85, and the pressure oil in the first oil chamber 81 flows into the second oil chamber 82. In addition, the piston member 77 stops and the volume of the first oil chamber 81 does not change. Therefore, the pressure oil in the first oil chamber 81 stagnates and the inflow of the pressure oil from the cavity 67 to the first oil chamber 81 also stops. Thereby, the pressure P1 of the pressure oil in the through hole 73, the pressure P2 of the pressure oil in the cavity 67, and the pressure P3 of the pressure oil in the first oil chamber 81 gradually increase, and finally the pressure in the high pressure passage 61 It rises to the same level as the oil pressure.

  As described above, when the pressure oil pressure in the high pressure passage 61 is larger than the pressure oil pressure in the low pressure passage 62 and the piston member 77 is in contact with the shoulder 85, the pressure oil pressure P1 in the through hole 73, the cavity The pressure P2 of the pressure oil in the portion 67 and the pressure P3 of the pressure oil in the first oil chamber 81 are the same.

  “The pressure oil pressure P2 in the cavity 67 when the pressure oil pressure in the high pressure passage 61 is larger than the pressure oil pressure in the low pressure passage 62 and the piston member 77 is separated from the shoulder portion 85 (see FIG. 5 ”indicates that“ the pressure of the cavity 67 when the pressure oil pressure in the high pressure passage 61 is greater than the pressure oil pressure in the low pressure passage 62 and the piston member 77 is in contact with the shoulder portion 85 ”. The pressure is smaller than the oil pressure P2 (see FIG. 6). On the other hand, due to the structure of the shockless relief valve 2, as the pressure oil pressure in the cavity 67 increases, the force required to push down the poppet 70 by the pressure oil in the high pressure passage 61 (that is, movement in the first direction D1). And the braking force and impact force provided by the shockless relief valve 2 are increased. Therefore, when the state shown in FIG. 5 is compared with the state shown in FIG. 6, the shockless relief valve 2 in the state shown in FIG. 5 can further reduce the impact force, and the shockless state in the state shown in FIG. The relief valve 2 can obtain a larger braking force.

  The shockless relief valve 2 of the present embodiment can perform shockless braking as a primary response according to the state shown in FIG. 5 and can perform normal braking as a secondary response according to the state shown in FIG. it can. Therefore, by adjusting the “movement speed of the piston member 77 in the second direction D2” and the “time from when the piston member 77 starts moving in the second direction D2 until it comes into contact with the shoulder portion 85”, the primary The time of response (ie shockless braking) and secondary response (ie normal braking) and the degree of braking can be varied. Specifically, the size of the slide space 79 in the axial direction, the channel area of the throttle hole 87, the channel area of the channel formed by the second throttle unit 76, and the flow formed by the first throttle unit 75. By adjusting the flow path area of the road, the time of primary response and secondary response and the degree of braking can be changed.

  As described above, in the shockless relief valve 2 of the present embodiment, shockless braking (primary response) is realized by the axial movement of the piston member 77 on the outer peripheral portion of the hollow main body 65. In particular, the above-described shockless relief valve 2 has a configuration in which an annular piston member 77 is mounted on the outer peripheral portion of a relief valve having a general structure, and thus can be easily downsized. It is also possible to easily attach to the oil passage (that is, the first load passage 51 and the second load passage 52). Further, the primary pressure response time can be changed easily and reliably by adjusting the speed and distance of the axial movement of the piston member 77, and the highly functional shockless relief valve 2 can be realized with a simple configuration.

[Hydraulic motor operation]
Next, the operation of the hydraulic motor 100 shown in FIG. 1 to which the above-described shockless relief valve 2 is applied will be described.

  Here, after the direction switching valve 101 is switched from the neutral position 101b to the first switching position 101a and the motor mechanism 1 is rotated, the direction switching valve 101 is returned to the neutral position 101b to brake the motor mechanism 1 and apply the motor. A case where the mechanism 1 is stopped will be described as an example. In this case, the first load passage 51 becomes the high pressure passage 61 and the second load passage 52 becomes the low pressure passage 62. When the direction switching valve 101 is switched to the second switching position 101c to rotate the motor mechanism 1 and then returned to the neutral position 101b to stop the motor mechanism 1, the second load passage 52 becomes the high-pressure passage 61. The first load passage 51 is a low pressure passage 62, and the motor mechanism 1 is braked by an operation mechanism similar to the operation mechanism described below.

[Driving of motor mechanism 1]
When the direction switching valve 101 is switched from the neutral position 101b to the first switching position 101a, the pressure oil from the pump 104 is supplied to the motor mechanism 1 through the second load passage 52, and the counter balance valve 3 is set to the neutral position. The position is switched from 3b to the first switching position 3a. When the counter balance valve 3 is switched to the first switching position 3a, the pressure oil is also supplied to the pressure chamber of the motor mechanism 1 through the passage 53, and the brake 32 (that is, the parking brake) of the motor mechanism 1 is released. When the counter balance valve 3 is switched to the first switching position 3a, the pressure oil discharged from the motor mechanism 1 is discharged to the tank 102 via the first load passage 51, the counter balance valve 3, and the direction switching valve 101. Is done. The motor mechanism 1 is rotationally driven by these series of operations.

[Stopping motor mechanism 1]
Next, the operation for stopping the motor mechanism 1 will be described. When the direction switching valve 101 is returned from the first switching position 101a to the neutral position 101b, the pump 104 is in communication with the tank 102, and the pressure of the pressure oil discharged from the pump 104 decreases. Thereby, the counter balance valve 3 returns from the 1st switching position 3a to the neutral position 3b. On the other hand, the motor mechanism 1 continues to rotate due to inertia. When the counterbalance valve 3 returns to the neutral position 3b, the first load passage 51 and the direction switching valve 101 are disconnected, so that the pressure oil discharged from the motor mechanism 1 that continues to rotate due to inertia flows to the tank 102. Since the first load passage 51 remains in the first load passage 51 without being discharged, the first load passage 51 becomes a high-pressure passage. On the other hand, the second load passage 52 is a low pressure passage.

  In this state, the shockless relief valve 2 operates. By the operation of the shockless relief valve 2, the pressure oil in the first load passage 51 flows into the second load passage 52 and returns to the motor mechanism 1. The resistance of the shockless relief valve 2 becomes a braking force, and the motor mechanism 1 stops after a predetermined time has elapsed.

  In particular, while the shockless relief valve 2 is in the state shown in FIG. 5 described above, the braking force provided by the shockless relief valve 2 is small, so that the braking distance is increased while the stop shock is alleviated. On the other hand, while the shockless relief valve 2 is in the state shown in FIG. 6 described above, since the braking force provided by the shockless relief valve 2 is large, the braking distance is shortened while the stop shock is increased. Thus, according to the shockless relief valve 2 of the present embodiment, the first half of the shockless braking (see FIG. 5) can alleviate the stop shock immediately after the braking of the motor mechanism 1 starts, while the latter half of the normal braking (see FIG. 6). It is possible to prevent the braking distance from becoming long.

  The present invention is not limited to the above-described embodiments and modifications, and can include various aspects to which various modifications that can be conceived by those skilled in the art can be included. The effects achieved by the present invention are also described above. It is not limited to the matter of. Therefore, various additions, modifications, and partial deletions can be made to each element described in the claims and the specification without departing from the technical idea and spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Motor mechanism 2 Shockless relief valve 3 Counter balance valve 4 High / low speed switching valve 5 Shuttle valve 32 Brake 51 1st load path 52 2nd load path 60 Main body 61 High pressure path 62 Low pressure path 64 Hollow body 65 Hollow body 66 Hollow plug part 67 Cavity 69 Base 70 Poppet 73 Through Hole 75 First Restriction 76 76 Second Restriction 77 Piston Member 79 Slide Space 81 First Oil Chamber 82 Second Oil Chamber 85 Shoulder 87 Restriction Hole 89 Elastic Member 91 Pressure Adjusting Member DESCRIPTION OF SYMBOLS 100 Hydraulic motor 101 Directional switching valve 102 Tank 103 Reduction gear 104 Pump 105 Pilot pump

Claims (6)

A shockless relief valve that blocks or communicates between the high-pressure passage and the low-pressure passage formed in the main body,
A hollow body having a cavity,
A poppet that is at least partially disposed in the hollow portion and is movably supported by an inner peripheral portion of the hollow body, and includes a through-hole communicating the high-pressure passage and the hollow portion, and a break of the through-hole. A poppet having a first throttle to locally reduce the area;
An annular piston member supported by an outer peripheral portion of the hollow body so as to be movable in the axial direction, and disposed in a slide space formed between the main body and the hollow body, and the slide space is axially A first oil chamber formed on one side of the piston member and a piston member divided into a second oil chamber formed on the other side of the piston member,
When the pressure difference between the pressure oil in the high-pressure passage and the pressure oil in the low-pressure passage is greater than a first value, the poppet is disposed at a position where the high-pressure passage and the low-pressure passage communicate with each other. When the difference is less than or equal to the first value, the high pressure passage and the low pressure passage are disposed at a position where they are blocked,
The hollow body has a second throttle part that communicates the cavity and the first oil chamber,
The second oil chamber communicates with the low pressure passage;
The main body is a shoulder portion defining a part of the second oil chamber, and has a shoulder portion that stops moving to the other side of the piston member by contacting the piston member,
The piston member moves in the axial direction in the slide space according to the difference between the pressure oil pressure in the first oil chamber and the pressure oil pressure in the second oil chamber, and the piston member is A shockless relief valve that shuts off the first oil chamber and the second oil chamber when in contact with each other. The piston member has at least one throttle hole;
The at least one throttle hole communicates the first oil chamber and the second oil chamber in a state where the piston member is separated from the shoulder portion, and the piston member is in contact with the shoulder portion. The shockless relief valve according to claim 1, wherein the shockless relief valve is closed by the shoulder portion and does not communicate the first oil chamber and the second oil chamber. An elastic member disposed in the cavity;
The shockless according to claim 1, further comprising: a pressure adjusting member provided between the poppet and the elastic member and capable of adjusting a force applied to the poppet from the elastic member by changing a thickness. Relief valve. In a state where the pressure oil pressure in the high pressure passage is greater than the pressure oil pressure in the low pressure passage and the piston member is away from the shoulder,
The pressure oil pressure between the high pressure passage and the first throttle portion in the through hole is larger than the pressure oil pressure in the cavity, and the pressure oil pressure in the cavity is the first oil. The shockless relief according to any one of claims 1 to 3, wherein the pressure oil pressure is greater than the pressure oil pressure in the chamber, and the pressure oil pressure in the first oil chamber is greater than the pressure oil pressure in the second oil chamber. valve. In a state where the pressure oil pressure in the high pressure passage is greater than the pressure oil pressure in the low pressure passage and the piston member is in contact with the shoulder,
The shockless relief valve according to any one of claims 1 to 4, wherein the pressure oil in the through hole, the pressure oil in the cavity, and the pressure oil in the first oil chamber have the same pressure.   The pressure oil pressure in the cavity in a state where the pressure oil pressure in the high pressure passage is larger than the pressure oil pressure in the low pressure passage and the piston member is separated from the shoulder portion is the pressure in the high pressure passage. The pressure of the oil is larger than the pressure of the pressure oil in the low pressure passage and smaller than the pressure of the pressure oil in the cavity in a state where the piston member is in contact with the shoulder. The shockless relief valve according to one item.

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