Fluid supply and discharge device

Abstract

This reduces the effects of grease accumulation and allows the piston member to move smoothly. [Solution] The pressurized oil supply / discharge device (2) comprises a cylindrical piston member (5) with a bottom, a female screw member (6) provided on the piston member (5), and a male screw member (7) that is inserted into a guide hole (53) of the piston member (5) and threads with the female screw member (6) to move the piston member (5) in the axial direction, the male screw member (7) having an internal passage (70) through which grease (G) applied to the male screw member (7) passes.

Description

[Technical Field]

[0001] The present invention relates to a fluid supply / discharge device that supplies and discharges a working fluid to and from a cylinder device. [Background technology]

[0002] There is known a fluid supply / discharge device that supplies and discharges hydraulic fluid to a clamp device (cylinder device) that switches between a locked state and a released state by the hydraulic fluid. A conventional fluid supply / discharge device of this type is described in Patent Document 1. This conventional technology is configured as follows.

[0003] A conventional fluid supply / discharge device includes a female screw member provided on a cylindrical piston member with a bottom, a male screw member inserted into the piston member and threadedly engaging with the female screw member to move the piston member in the axial direction, and a working chamber into which working fluid is supplied and discharged as the piston member moves. As the male screw member rotates, the female screw member moves in the axial direction, thereby moving the piston member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-067886 Summary of the Invention [Problem to be solved by the invention]

[0005] In this type of fluid supply / discharge device, semi-solid grease (lubricant) is applied to the female and male threaded members to reduce wear at the threaded portions and ensure smooth operation. Grease tends to accumulate on the end of the male threaded member as the female threaded member moves back and forth in the axial direction, which can hinder the smooth movement of the piston member.

[0006] An object of one aspect of the present invention is to reduce the effects of grease accumulation and to smooth the movement of the piston member. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a fluid supply / discharge device configured as follows, as shown in, for example, FIGS. The fluid supply / discharge device (pressurized oil supply / discharge device) 2 comprises a bottomed, cylindrical piston member 5 that is inserted into a housing 10 so as to be axially movably and has a guide hole 53 therein, a female screw member 6 provided on the piston member 5, a male screw member 7 that is inserted into the guide hole 53 and screws into the female screw member 6 to move the piston member 5 in the axial direction, the male screw member 7 having an internal passage 70 through which grease G applied to the male screw member 7 passes, and a working chamber 9 into which a working fluid F is supplied and discharged as the piston member 5 moves.

[0008] One aspect of the present invention provides the following advantageous effects. When the female screw member moves along the axial direction of the male screw member, the piston member attached to the female screw member moves. At this time, the grease is pushed as the female screw member moves in the axial direction, and grease accumulation may occur, for example, on the end side of the male screw member. In the fluid supply / discharge device, the male screw member has an internal passage through which grease passes, allowing the grease to move inside the male screw member through the internal passage. This reduces the impact of grease accumulation and allows the piston member to move smoothly.

[0009] The present invention preferably includes the following features (1) to (4).

[0010] (1) For example, as shown in FIG. 6 , the internal passage 70 includes a first passage 71 that passes through the axial center of the male thread member 7 and opens at the tip of the male thread member 7 located on the bottom 54 side of the piston member 5, a second passage 72 that branches off from the first passage 71 and opens at the outer peripheral surface of the base end side of the male thread member located opposite the tip, and a third passage 73 that branches off from the first passage 71 and opens at the outer peripheral surface of the tip side relative to the second passage 72. In this case, grease accumulated on the tip end side of the male screw member can be made to flow into the first passage and then discharged from the outer circumferential surface of the male screw member via the third passage, and can be reused. Also, grease accumulated on the base end side of the male screw member can be made to flow into the second passage and then discharged from the outer circumferential surface of the male screw member via the first and third passages, and can be reused.

[0011] (2) For example, as shown in Figures 2 and 6, when the piston member 5 is located at the stroke end on the base end side of the male screw member 7, the second passage 72 opens on the base end side relative to the female screw member 6, and the third passage 73 opens on the tip end side relative to the female screw member 6. In this case, the second and third passages can be arranged to avoid the female screw member. Also, for example, grease that has flowed into the internal passages from the tip end and base end of the male screw member can be discharged to the outer circumferential surface of the male screw member from near the middle position in the axial direction of the male screw member.

[0012] (3) For example, as shown in Figures 1 to 6, the housing 10 is separated from the operating chamber 9 by the piston member 5 and has an internal space S in which the female screw member 6 and the male screw member 7 are arranged, and the internal space S is airtight so that air cannot enter or exit. In this case, there is no suction hole (breath hole) for supplying or exhausting air from the internal space of the housing to the outside, so grease does not scatter (leak) to the outside through the breathing hole. This prevents a decrease in lubrication due to a decrease in grease and an increase in drive resistance. It also prevents damage to parts inside the internal space due to corrosion or wear caused by liquids, dust, etc. that have entered the internal space from the outside.

[0013] (4) For example, as shown in Figures 1, 3 and 5, the air pressure in the internal space S is adjusted to be equal to the external air pressure (1 atmosphere, atmospheric pressure) when the piston member 5 is at the intermediate position of the piston stroke length. In this case, the air pressure in the airtight internal space can be prevented from becoming extremely high or low, thereby reducing the effect of changes in air pressure in the internal space on the piston member and allowing the piston member to move smoothly. [Effects of the Invention]

[0014] According to one aspect of the present invention, the influence of grease accumulation can be reduced, and the movement of the piston member can be made smoother. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a cross-sectional view showing a main part of the hydraulic cylinder unit according to the embodiment. [Figure 2] 4 is a cross-sectional view showing an initial state in which a piston member of the pressure oil supply / discharge device is at an upper stroke end position. FIG. [Figure 3] 3 is a cross-sectional view showing a state in which the piston member has moved from the upper stroke end position shown in FIG. 2 to a stroke intermediate position. [Figure 4] 4 is a cross-sectional view showing a state in which the piston member has moved from the stroke intermediate position shown in FIG. 3 to the stroke lower end position. [Figure 5] 5 is a cross-sectional view showing a state in which the piston member has moved from the stroke lower end position shown in FIG. 4 to the stroke intermediate position. [Figure 6] 6 is a cross-sectional view showing a state in which the piston member has moved from the stroke intermediate position shown in FIG. 5 to the stroke upper end position. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of the present invention will be described below. Note that the following description is an example of a fluid supply / drainage device according to the present invention, and the technical scope of the present invention is not limited to the illustrated example.

[0017] [Configuration of hydraulic cylinder unit] Fig. 1 is a cross-sectional view showing a main part of a hydraulic cylinder unit 1 according to this embodiment. As shown in Fig. 1, the hydraulic cylinder unit 1 includes a pressure oil supply / discharge device (fluid supply / discharge device) 2, and a cylinder device 3 that receives a hydraulic oil (working fluid) F from the pressure oil supply / discharge device 2 and discharges the hydraulic oil F to the pressure oil supply / discharge device 2. The hydraulic cylinder unit 1 also includes a pressure accumulator 4 that is provided between the pressure oil supply / discharge device 2 and the cylinder device 3 and that maintains the hydraulic pressure of the hydraulic oil F in the event of a pressure drop (drop in hydraulic pressure) caused by a leak of the hydraulic oil F or the like.

[0018] The pressure oil supply and discharge device 2 and the cylinder device 3 are in communication with each other via a pressure accumulator device 4 and a fluid passage 11 through which hydraulic oil F passes. In this embodiment, the hydraulic oil F discharged from the pressure oil supply and discharge device 2 flows into the fluid passage 11 via the pressure accumulator device 4, and is supplied to the cylinder device 3 through the fluid passage 11. Furthermore, the hydraulic oil F discharged from the cylinder device 3 flows into the fluid passage 11, and is supplied to the pressure oil supply and discharge device 2 via the pressure accumulator device 4. The pressure oil supply and discharge device 2, the cylinder device 3, and the pressure accumulator device 4 may be provided on a plate-shaped conveying member configured to be movable along a track, for example.

[0019] In the following explanation, the direction in which the bottomed cylindrical piston member 5 provided in the pressurized oil supply / discharge device 2 moves will be referred to as the vertical direction (axial direction), and the bottom 54 side of the piston member 5 in the vertical direction will be referred to as the lower side (lower part), and the side opposite the lower side will be referred to as the upper side (upper part), etc.

[0020] (Pressure oil supply and discharge device) The pressure oil supply and discharge device 2 comprises a hollow housing 10, a cylindrical piston member 5 with a bottom that is inserted into the housing 10 so as to be axially movable, a female screw member 6 provided in a receiving hole 51 formed in the upper part of the piston member 5, and a male screw member 7 that screws into the female screw member 6. The pressure oil supply and discharge device 2 also comprises a cap member 8 that is connected to the upper end (base end) opposite to the lower end (tip end) that is the male screw formed end of the male screw member 7, and that transmits rotational force around the axis to the male screw member 7, and a working chamber 9 that is formed on the lower side (bottom 54 side) of the piston member 5 and into which hydraulic oil F is supplied and discharged as the piston member 5 moves.

[0021] The cap member 8 is a cylindrical member connected to the upper end of the male screw member 7 by a bolt 21. When the cap member 8 rotates around its axis, the male screw member 7 rotates.

[0022] The cap member 8 has an operating portion 81 at its top for receiving a rotational force around the axis. The operating portion 81 has a polygonal protrusion that fits into a recess formed in a rotational force transmission tool T (see FIG. 2) for transmitting a rotational force to the cap member 8.

[0023] The cap member 8 also has an insertion hole 82 into which the non-male-threaded portion on the upper end side of the male-threaded member 7 is inserted, and a guide groove 83 formed in the axial direction on the inner peripheral surface of the insertion hole 82. The insertion hole 82 is provided in the lower part of the cap member 8. A parallel pin 22 that engages with the guide groove 83 is provided between the inner peripheral surface of this insertion hole 82 and the outer peripheral surface of the male-threaded member 7. Furthermore, the cap member 8 has a sliding groove 84 formed in the circumferential direction on the lower part of its outer peripheral surface. A plurality of bearings (ball members) 23 are mounted in this sliding groove 84.

[0024] The piston member 5 is a bottomed cylindrical member having a bottom 54 on the axially lower side. The piston member 5 is hermetically fitted into the housing 10 so as to be movable in the axial direction. The piston member 5 is provided with a female screw member 6 on the upper part of its inner circumferential surface (inner circumferential wall). The piston member 5 also has a guide groove 52 formed in the axial direction on its outer circumferential surface (inner circumferential wall). A parallel pin 24 that engages with the guide groove 52 is provided between the outer circumferential surface of the piston member 5 and the housing 10. Furthermore, the piston member 5 has a guide hole 53 formed therein into which the male screw member 7 can be inserted.

[0025] The female screw member 6 has a female screw formed on its inner peripheral surface. The male screw member 7 has a male screw formed on its outer peripheral surface that screws into the female screw. As the male screw member 7 rotates, the female screw member 6 moves up and down along the male screw member 7. As the female screw member 6 moves, the piston member 5 moves up and down.

[0026] As the piston member 5 moves up and down, the hydraulic oil F in the working chamber 9 is pressurized or depressurized, and the hydraulic oil F is supplied to and discharged from the cylinder device 3. For example, when the piston member 5 moves downward in the axial direction, the hydraulic oil F in the working chamber 9 is compressed. As a result, the hydraulic oil F is supplied to the cylinder device 3 through the supply and discharge path 25 provided in the housing 10. On the other hand, when the piston member 5 moves upward in the axial direction, the hydraulic oil F is depressurized. As a result, the hydraulic oil F is discharged from the cylinder device 3.

[0027] Here, semi-solid grease G is applied to the female screw member 6 and the male screw member 7 to reduce wear at the threaded portions and ensure smooth operation. If this grease G accumulates, for example, at the top or bottom of the male screw member 7, it may interfere with smooth movement of the piston member 5, as will be described later. Therefore, in the pressure oil supply / discharge device 2, an internal passage 70 is formed in the male screw member 7 to allow the grease G to pass through.

[0028] In this embodiment, the internal passage 70 includes a first passage 71 that passes through the axial center of the male thread member 7 and opens at the lower end of the male thread member located on the bottom 54 side of the piston member 5, a second passage 72 that branches off from the first passage 71 and opens at the outer peripheral surface of the upper end side of the male thread member 7 located opposite the lower end, and a third passage 73 that branches off from the first passage 71 and opens at the outer peripheral surface of the lower end side of the second passage 72.

[0029] The first passage 71 is formed through the axial center of the male screw member 7 and communicates with a first opening 71A that opens at the lower end of the male screw member 7. The second passage 72 is formed radially from the first passage 71 and communicates with a second opening 72A that opens on the outer peripheral surface of the upper end side of the male screw member 7. The third passage 73 is formed radially from the first passage 71 and communicates with a third opening 73A that opens on the outer peripheral surface of the lower end side of the second opening 72A. Note that the male screw member 7 may be provided with a plurality of second passages 72 and a plurality of third passages 73.

[0030] The housing 10 also has an internal space S, separated from the operating chamber 9 by the piston member 5 hermetically fitted within the housing 10, in which the female screw member 6 and the male screw member 7 are disposed. This internal space S may be airtight to prevent air from entering or leaving. In other words, the housing 10 does not need to be provided with a breathing hole for discharging air within the internal space S, including the guide hole 53 of the piston member 5, to the outside or for introducing external air into the internal space S. This prevents grease G from scattering (leaking) to the outside through the breathing hole, thereby preventing a decrease in lubricity due to a decrease in grease G and an increase in drive resistance. Furthermore, it is possible to prevent damage to components within the internal space S due to corrosion or wear caused by liquid, dust, etc. that has flowed into the internal space S from the outside.

[0031] (Cylinder device) The cylinder device 3 is a device that is operated by hydraulic oil F. The cylinder device 3 may be, for example, a clamp device or the like that is switched between a locked state and a released state by the hydraulic oil F.

[0032] The cylinder device 3 has a hollow housing 30, a piston member 31 inserted into the housing 30 so as to be axially (vertically) movable, an output rod 32 protruding from the top of the piston member 31, and an operating chamber 33 arranged below the piston member 31. The cylinder device 3 also has a spring chamber 34 arranged on the opposite side of the piston member 31 from the operating chamber 33, i.e., above the piston member 31, and a biasing spring 35 attached to the spring chamber 34 and biasing the piston member 31 toward the operating chamber 33. The operating chamber 33 is in communication with the fluid passage 11.

[0033] When hydraulic oil F is supplied to the cylinder device 3 through the fluid passage 11, the pressing force based on the hydraulic oil F supplied to the working chamber 33 moves the piston member 31 toward the output rod 32, i.e., axially upward, against the biasing force of the biasing spring 35. On the other hand, when the hydraulic oil F is discharged from the cylinder device 3 through the fluid passage 11, the pressing force based on the hydraulic oil F supplied to the working chamber 33 decreases, and the biasing force of the biasing spring 35 moves the piston member 31 axially downward.

[0034] It should be noted that the hydraulic cylinder unit 1 may be provided with a plurality of cylinder devices 3. Furthermore, the cylinder device 3 may be any device that is actuated by hydraulic oil F, and is not limited to a clamp device.

[0035] (Accumulator) The pressure accumulator 4 is an accumulator connected to the pressure oil supply / discharge device 2. The pressure accumulator 4 includes a housing 40 having a pressure accumulator chamber 41 formed therein for storing hydraulic oil F, a pressure accumulator piston member 42 inserted into the housing 40 so as to be movable in the axial direction (up and down direction in the drawing), and a compression spring 43 which is an elastic member that biases the pressure accumulator piston member 42 toward the pressure accumulator chamber 41 side.

[0036] The housing 40 includes a first accommodating hole 40A and a second accommodating hole 40B having a larger diameter than the first accommodating hole 40A. A pressure accumulator piston member 42 is hermetically fitted into the first accommodating hole 40A so as to be movable in the axial direction. A pressure accumulator chamber 41 is disposed axially below the pressure accumulator piston member 42.

[0037] The accumulator chamber 41 communicates with the pressure oil supply and discharge device 2 via a first supply and discharge passage 44A provided in the housing 40. The accumulator chamber 41 also communicates with the fluid passage 11 via a second supply and discharge passage 44B provided in the housing 40. A sealing member 45 is provided in the circumferential direction on the inner peripheral surface of the first accommodating hole 40A that faces the outer peripheral surface of the accumulator piston member 42. The sealing member 45 is capable of hermetically engaging with the outer peripheral surface of the accumulator piston member 42.

[0038] The pressure accumulator 4 further includes an indicator rod 46 provided axially above the pressure accumulator piston member 42 and protruding in the axial direction. The indicator rod 46 is accommodated in the second accommodating hole 40B. Between , which forms a spring chamber 47 that houses the compression spring 43. In this spring chamber 47, the compression spring 43 that urges the indicator rod 46 toward the pressure accumulator chamber 41 is arranged around the outer circumferential surface of the indicator rod 46. The indicator rod 46 has a flange on the end side that is connected to the pressure accumulator piston member 42, and the flange functions as a spring receiver 46A that receives the compression spring 43.

[0039] As will be described later, a tip end 46B of the indicator rod 46 opposite the spring bearing 46A is configured to pass through a through-hole 40C formed in the housing 40 and protrude outside the housing 40 as the pressure accumulator piston member 42 moves axially upward (see FIG. 4). Therefore, when hydraulic oil F is stored in the pressure accumulator chamber 41, the tip end 46B of the indicator rod 46 protrudes outside the housing 40. This makes it possible to visually check whether the pressure accumulator piston member 42 is moving normally based on the protruding state of the tip end 46B, making it easier to discover any malfunctions in the pressure accumulator device 4.

[0040] (Operation of hydraulic clamp unit) Next, an example of the operation of the hydraulic cylinder unit 1 will be described. FIGS. 2 to 6 are cross-sectional views showing an example of the operation of the hydraulic cylinder unit 1. Specifically, FIG. 2 shows an initial state in which the piston member 5 of the pressure oil supply / discharge device 2 is at the upper stroke end position. FIG. 3 shows a state in which the piston member 5 has moved from the upper stroke end position shown in FIG. 2 to the middle stroke position, and FIG. 4 shows a state in which the piston member 5 has moved from the middle stroke position shown in FIG. 3 to the lower stroke end position. Furthermore, FIG. 5 shows a state in which the piston member 5 has moved from the lower stroke end position shown in FIG. 4 to the middle stroke position, and FIG. 6 is a cross-sectional view showing a state in which the piston member 5 has moved from the middle stroke position shown in FIG. 5 to the upper stroke end position.

[0041] As shown in Figures 2 to 4, the pressure oil supply / discharge device 2 supplies hydraulic oil F to the cylinder device 3 when the piston member 5 moves from the upper stroke end position, which is the initial state, to the lower stroke end position. Also, as shown in Figures 4 to 6, the pressure oil supply / discharge device 2 discharges hydraulic oil F from the cylinder device 3 when the piston member 5 moves from the lower stroke end position to the upper stroke end position.

[0042] As shown in Figure 2, when the piston member 5 of the pressure oil supply / discharge device 2 is at the upper end of the stroke, the female screw member 6 is located above the male screw forming portion of the male screw member 7, and the piston member 5 is located directly below the cap member 8.

[0043] First, a recess formed at the tip of the torque transmission tool T for transmitting torque to the cap member 8 is fitted into the operating portion 81 of the cap member 8. Thereafter, when the torque transmission tool T is rotated in a first direction about its axis by operation by an operator or a robot, the cap member 8 fitted into the recess of the torque transmission tool T transmits the torque to the male screw member 7. When the male screw member 7 rotates due to the torque, the female screw member 6 that threads into the male screw member 7 moves axially downward, and the piston member 5 provided in the female screw member 6 moves axially downward so as to move away from the cap member 8.

[0044] At this time, as shown in Fig. 3, as the female screw member 6 that threads onto the male screw member 7 moves downward in the axial direction, a portion (reference symbol G1 in the figure) of the grease G applied to the male screw member 7 is pushed downward by the female screw member 6 and moves. For this reason, as shown in Fig. 4, when the piston member 5 moves to the vicinity of the lower end position of the stroke, a grease pool G2 may be formed at the lower end of the male screw member 7.

[0045] As the piston member 5 moves downward in the axial direction, the pressure of the hydraulic oil F is increased in the working chamber 9, and the pressurized hydraulic oil F flows into the fluid passage 11 via the pressure accumulator 4, and is supplied to the working chamber 33 of the cylinder device 3 through the fluid passage 11. As the hydraulic oil F is supplied to the working chamber 33 of the cylinder device 3, a pressing force based on the hydraulic oil F supplied to the working chamber 33 acts to move the piston member 31 upward.

[0046] Next, with the piston member 31 of the cylinder device 3 moved to the upper stroke end position, the torque transmitting tool T further rotates the cap member 8 of the pressure oil supply / discharge device 2 in the first direction about its axis. This further increases the pressure of the hydraulic oil F. As a result, the hydraulic oil F in the working chamber 9 of the pressure oil supply / discharge device 2 is supplied to the accumulator chamber 41 of the pressure accumulator 4.

[0047] 4, a pressing force corresponding to the oil pressure of the hydraulic oil F supplied to the pressure accumulator chamber 41 moves the pressure accumulator piston member 42 axially upward against the biasing force of the compression spring 43. As the pressure accumulator piston member 42 moves axially upward, the tip end 46B of the indicator rod 46 projects outward from the housing 40. This makes it possible to visually confirm that the hydraulic oil F is being supplied to the pressure accumulator chamber 41 based on the projecting state of the tip end 46B.

[0048] For example, when a pressure drop of the hydraulic oil F in the fluid passage 11 occurs due to leakage of the hydraulic oil F or the like, the accumulator piston member 42 of the pressure accumulator device 4 compresses the accumulator chamber 41 due to the biasing force of the compression spring 43. Therefore, the hydraulic oil F stored in the accumulator chamber 41 is discharged to the fluid passage 11 in response to the pressure drop of the hydraulic oil F. This makes it possible to mitigate the pressure drop of the hydraulic oil F.

[0049] On the other hand, when the piston member 5 is at the stroke lower end position shown in Fig. 4 and the rotational force transmitting tool T rotates around the axis in a second direction opposite to the first direction, the piston member 5 moves axially upward so as to approach the cap member 8, as shown in Fig. 5 and Fig. 6. Then, the pressure of the hydraulic oil F decreases, and first, the hydraulic oil F stored in the accumulator chamber 41 of the accumulator 4 is discharged into the fluid passage 11 by the biasing force of the compression spring 43, and then the hydraulic oil F in the cylinder device 3 is discharged through the fluid passage 11 into the working chamber 9 of the pressure oil supply / discharge device 2.

[0050] At this time, as shown in Fig. 5, as the female screw member 6 that threads onto the male screw member 7 moves axially upward, a portion of the grease G applied to the male screw member 7 is pushed upward and moves by the female screw member 6 (reference symbol G3 in the figure). For this reason, as shown in Fig. 6, when the piston member 5 moves near the upper end position of the stroke, a grease pool G4 may form on the outer peripheral surface near the upper end of the male screw member 7.

[0051] If grease pools G2 and G4 are formed, when the piston member 5 moves near the upper end of the stroke, the grease pools G2 and G4 will resist the upward axial movement of the piston member 5, hindering smooth movement of the piston member 5. As a result, a greater rotational force is required to rotate the cap member 8 in the second direction, and a load will be applied to the rotational force transmission tool T that rotates the cap member 8 in the second direction.

[0052] As described above, the male thread member 7 is formed with an internal passage 70 for passing the grease G, including the first passage 71, the second passage 72, and the third passage 73. This reduces the effects of grease pools G2 and G4.

[0053] Specifically, as shown in Fig. 6, when the piston member 5 moves to the upper stroke end position, a part of the grease G that constitutes the grease pool G2 formed at the lower end of the male screw member 7 flows into the first passage 71 from the first opening 71A (arrow A1 in the figure). Tag Squirrel Pool G 4 Some of the grease that makes up G The grease flows from the second opening 72A into the second passage 72 (arrow A2 in the figure). This reduces the influence of the grease pools G2 and G4, and allows the piston member 5 to move smoothly.

[0054] Furthermore, the grease G that flows into the first passage 71 from the first opening 71A passes through the third passage 73 and is discharged from the third opening 73A. Similarly, the grease G that flows into the second passage 72 from the second opening 72A passes through the first passage 71 and the third passage 73 and is discharged from the third opening 73A (arrow A3 in the figure). Therefore, the grease G that flows into the internal passage 70 is discharged to the outer peripheral surface of the male thread member 7, and the grease G can be reused.

[0055] When the piston member 5 is at the upper end of its stroke, it is preferable that the second passage 72 opens at the upper end side relative to the female screw member 6, and the third passage 73 opens at the lower end side relative to the female screw member 6. In other words, when the piston member 5 is at the upper end of its stroke, it is preferable that the second opening 72A is located at the upper end side relative to the female screw member 6, and the third opening 73A is located at the lower end side relative to the female screw member 6. This allows the second passage 72 and the third passage 73 to be positioned so as to avoid the female screw member 6. In addition, the grease G that has flowed into the internal passage 70 can be discharged to the outer peripheral surface of the male screw member 7 from approximately the middle position in the axial direction of the male screw member 7.

[0056] Furthermore, it is preferable that the air pressure (internal pressure) within the internal space S of the housing 10 is adjusted so that it is equal to the external air pressure (1 atmosphere, atmospheric pressure) when the piston member 5 is at the midpoint of the piston stroke length. As the volume of the internal space S changes as the piston member 5 moves in the axial direction, the air pressure within the airtight internal space S changes. For example, the air pressure within the internal space S is maximum when the piston member 5 is at the top end of the stroke, and is minimum when the piston member 5 is at the bottom end of the stroke.

[0057] Therefore, when the piston member 5 is at the intermediate position of the piston stroke length, that is, when the piston member 5 is at the intermediate position between the upper and lower stroke end positions as shown in Figures 3 and 5, the air pressure in the internal space S is adjusted to, for example, 1 atmosphere. This makes it possible to prevent the air pressure in the internal space S from becoming extremely high or low. This reduces the effect that changes in the air pressure in the internal space S have on the piston member 5, making it possible to smooth the movement of the piston member 5.

[0058] [Summary of pressure oil supply and discharge equipment] As described above, the pressurized oil supply and discharge device 2 according to this embodiment comprises a bottomed cylindrical piston member 5 which is inserted into the housing 10 so as to be movable in the axial direction and has a guide hole 53 therein, a female screw member 6 provided on the piston member 5, a male screw member 7 which is inserted into the guide hole 53 and screws into the female screw member 6 to move the piston member 5 in the axial direction, the male screw member 7 having an internal passage 70 through which grease G applied to the male screw member 7 passes, and a working chamber 9 into which hydraulic oil F is supplied and discharged as the piston member 5 moves.

[0059] In the pressure oil supply / discharge device 2, the piston member 5 provided in the female screw member 6 moves as the female screw member 6 moves along the axial direction of the male screw member 7. At this time, the grease G is pushed as the female screw member 6 moves in the axial direction, which may result in grease accumulations G2 and G4 on both end sides of the male screw member 7. In the pressure oil supply / discharge device 2, the male screw member 7 has an internal passage 70 through which grease passes, so the grease G can move inside the male screw member 7 through the internal passage 70. Therefore, according to this embodiment, the effects of the grease accumulations G2 and G4 can be reduced, and the movement of the piston member 5 can be made smoother.

[0060] Although the present embodiment has been described with reference to an example of a pressure oil supply / discharge device that supplies hydraulic pressure to a cylinder device, the present invention is not limited to this. For example, the present invention can also be applied to an air supply / discharge device that supplies compressed air to a cylinder device instead of hydraulic pressure.

[0061] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in the embodiments. [Explanation of symbols]

[0062] 2: Pressure oil supply and discharge device (fluid supply and discharge device) 5: Piston material 6: Female threaded member 7: Male threaded member 10: Housing 53: Guide hole 54: Bottom 70: Internal passage 71:1st aisle 72:Second aisle 73: 3rd aisle 71A: 1st opening 72A: 2nd opening 73A: Third opening F: Hydraulic oil (working fluid) G: Grease G1: Grease G2: Grease accumulation G3: Grease G4: Grease accumulation S:Internal space

Claims

1. a piston member having a cylindrical shape with a bottom and a guide hole therein, the piston member being inserted into the housing so as to be movable in the axial direction; a female screw member provided on the piston member; a male screw member that is inserted into the guide hole and threadedly engages with the female screw member to move the piston member in the axial direction, the male screw member having an internal passage through which grease applied to the male screw member passes; a working chamber into which working fluid is supplied and discharged by movement of the piston member; Equipped with The internal passageway is a first passage that passes through the axial center of the male screw member and opens at a tip end of the male screw member that is located on the bottom side of the piston member; a second passage branching from the first passage and opening at an outer peripheral surface of a base end side of the male thread member located on the opposite side from the tip end portion; a third passage branching from the first passage and opening at the outer circumferential surface on the tip end side relative to the second passage; Including, When the piston member is located at the stroke end on the base end side of the male screw member, the second passage opens at the base end side relative to the female screw member, The third passage opens at the tip end side of the female screw member.

2. the housing has an internal space that is partitioned from the working chamber by the piston member and in which the female screw member and the male screw member are disposed, The fluid supply / drainage device according to claim 1 , wherein the internal space is airtight so that air does not enter or leave the internal space.

3. 3. The fluid supply / discharge device according to claim 2, wherein the air pressure in the internal space is adjusted to be equal to the external air pressure when the piston member is at an intermediate position of the piston stroke length of the piston member.

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