Pressurizing device

Abstract

Provided is a pressurizing device configured so that there is a large amount of expansion / contraction in the axial-direction length of the device.　A pressure transmission body includes a pair of movable members 3, 4 that can move relatively in the axial direction with respect to a case 2 constituting a section of a pressure accumulation part 10. In at least a contracted state of the pressurizing device 1, at least sections of the pair of movable members 3, 4 overlap in the axial direction when seen from the radial direction.

Description

Pressure device

[0001] The present invention relates to a pressure device for applying pressure to an object to be acted upon.

[0002] There is a type of pressure device that uses a cylinder device as a pressure device that uses the pressure of a fluid to pressurize an object to be acted upon, and the piston moves within the cylinder when it receives the pressure of the fluid, thereby pressurizing the object to be acted upon.

[0003] For example, the pressure device in Patent Document 1 is composed of a pair of cylinder devices. The cylinder devices include a case and a piston. The case is cylindrical with a bottom. The piston is composed of a plate-shaped large diameter portion and a cylindrical small diameter portion. The opposing surfaces of the large diameter portions of the pair of pistons are connected to each other, and the small diameter portions extend in opposite directions from the large diameter portion. The pair of cases are fitted externally to the small diameter portions on both axial sides so as to be movable relative to them.

[0004] A cylinder device is filled with high-pressure gas. On both sides of this pressurizing device, there are objects to be acted upon, whose axial position can be changed. The pressurizing device is designed so that the case and piston expand and contract according to the position of the acted upon objects on both sides due to the pressure of the sealed-in high-pressure gas, and pressurize the acted upon objects without the need for an external fluid supply such as an accumulator or pump.

[0005] WO 2023 / 243703 (page 15, Figure 8)

[0006] In Patent Document 1, a pair of cylinder devices arranged opposite to each other is used to apply pressure to an object in the axial direction. However, the amount of expansion and contraction of the pressure device relative to the axial length is small.

[0007] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a pressure device that has a large amount of expansion and contraction relative to the axial length of the device.

[0008] In order to solve the above problems, the present invention provides a pressurizing device including a pressure accumulator and a pressure transmitter that transforms the pressure of the pressure accumulator and transmits the transformed pressure to an acted-on body, wherein the pressure transmitter has a pair of movable members that are movable in the axial direction relative to a case that constitutes a part of the pressure accumulator, and the pair of movable members at least partially overlap in the axial direction as viewed from the radial direction, at least in a contracted state of the pressurizing device. According to this, since the pair of movable members partially overlap in the axial direction in the contracted state of the pressurizing device, a large amount of expansion and contraction relative to the axial length of the pressurizing device can be ensured.

[0009] The pair of movable members may be disposed on both axial sides of the case, and the case may have a fixing portion fixed to the device to be attached. In this way, the pair of movable members move relative to the case fixed to the device to be attached, so that pressure can be applied stably to the acted-on bodies on both axial sides.

[0010] One of the movable members may be fitted to the outer circumferential surface of the case in a sealed manner so as to be movable relative to the outer circumferential surface of the case, and the other movable member may be fitted to the inner circumferential surface of the case in a sealed manner so as to be movable relative to the inner circumferential surface of the case. In this way, the pair of movable members are sealedly attached to the inside and outside of the fixed case, resulting in high sealing performance.

[0011] The fixed portion may be provided at an end of the case opposite to the one movable member, whereby the one movable member can move axially to the vicinity of the opposite end of the case, thereby ensuring a large amount of expansion and contraction of the pressure device.

[0012] When the pressure applying device is in a contracted state, a gap may be formed between the fixed part and the one of the movable members, thereby preventing a sudden change in pressure applied to the object due to contact between the fixed part and the one of the movable members when the pressure applying device is in a contracted state.

[0013] The fixing portion may be engaged with the fixed portion of the device to be attached. In this way, the case is fixedly disposed relative to the device to be attached by the engagement between the fixing portion and the fixed portion, and therefore vibrations of the device to be attached can be absorbed by a minute clearance between the engaging portion and the fixed portion, thereby suppressing transmission of the vibrations to the case.

[0014] A plurality of the pressure transmitting bodies may be provided, whereby the pressure transmitting bodies exert pressure at a plurality of locations, stabilizing the expansion and contraction operation of the pressure device.

[0015] The pressure transmitting bodies may be oriented in the same axial direction, so that the pressure applied to each of the acted-on bodies by each pressure transmitting body is approximately the same.

[0016] The pressure transmitting bodies may be connected to the same pressure accumulating portion, thereby stabilizing the pressure applied by each pressure transmitting body.

[0017] The pressure transmitting bodies may be attached to the same fixing portion, so that the pressure transmitting bodies can be integrated, thereby stabilizing the pressure applied to the object to be acted upon.

[0018] The pressure transmitting bodies may be oriented in opposite directions in the axial direction, so that the sum of the pressure forces applied to the acted-on bodies on both sides by the pressure transmitting bodies is approximately the same.

[0019] FIG. 1 is a perspective view showing a pressure device in a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing a contracted state of the pressure device in the first embodiment. FIG. 3 is a longitudinal sectional view showing an extended state of the pressure device in the first embodiment. FIG. 4 is a longitudinal sectional view showing a contracted state of the pressure device in the first embodiment. FIG. 5 is a longitudinal sectional view showing an extended state of the pressure device in the second embodiment of the present invention. FIG. 6 is a longitudinal sectional view showing an extended state of the pressure device in the second embodiment. FIG. 7 is a longitudinal sectional view showing an extended state of the pressure device in the third embodiment of the present invention. FIG. 8 is a longitudinal sectional view showing an extended state of the pressure device in the third embodiment of the present invention. FIG. 9 is a longitudinal sectional view showing an extended state of the pressure device in the fourth embodiment of the present invention. FIG. 10 is a longitudinal sectional view showing an extended state of the pressure device in the fourth embodiment of the present invention. FIG. 11 is a longitudinal sectional view showing an extended state of the pressure device in the fourth embodiment of the present invention. FIG. 12 is a longitudinal sectional view showing an extended state of the pressure device in the fifth embodiment of the present invention.

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pressurizing device according to the present invention will be described below with reference to an embodiment.

[0021] A pressure device according to a first embodiment will be described with reference to Fig. 1 to Fig. 3. In the following description, the right side of Fig. 2 corresponds to the right side of the pressure device, and the left side of Fig. 2 corresponds to the left side of the pressure device.

[0022] 1, the pressure applying device 1 applies pressure to the workpieces W1 and W2 arranged on both sides in the axial direction by utilizing the pressure of a fluid. In this embodiment, the workpiece W1 is arranged on the right side of the pressure applying device 1, and the workpiece W2 is arranged on the left side of the pressure applying device 1. The positions of the workpieces W1 and W2 (see FIG. 2) to be applied are assumed to change in the axial direction, i.e., in the left-right direction on the paper surface of FIG. 2, depending on the state of use.

[0023] As shown in FIGS. 1 and 2, the pressurizing device 1 is mainly composed of a case 2, a first piston 3 as one movable member, and a second piston 4 as the other movable member.

[0024] The case 2 has a cylindrical portion 2a and a flange portion 2b as a fixing portion.

[0025] Two annular recesses 2c, 2d are provided at the right end of the outer peripheral surface of the cylindrical portion 2a, spaced apart in the axial direction and recessed in the inward direction. A seal ring 8 is fitted into the right annular recess 2c. The left annular recess 2d is shallower than the annular recess 2c, and no member such as the seal ring 8 is fitted into it.

[0026] The seal ring 8 may be an O-ring, but may also be an X-ring, lip seal, or other type. The annular recess 2d has an oil reservoir function, allowing for smooth sliding as described below. The annular recess 2d may be located anywhere in the axial direction of the outer circumferential surface of the cylindrical portion 2a as long as it can improve sliding properties.

[0027] The flange 2b extends radially outward from the left end of the cylindrical portion 2a. The case 2 is fixed to the mounting device via the flange 2b. 1 to 3 show only the mounting fixture 5 as the fixed portion of the mounting device.

[0028] Specifically, a mounting fixture 5 divided into upper and lower halves is fixed to the device to be mounted. A through-hole 5a is provided in the center of the mounting fixture 5. The mounting fixture 5 is composed of an upper member 51 and a lower member 52, and the joint surfaces of the upper member 51 and the lower member 52 cross the through-hole 5a from front to back.

[0029] Furthermore, in the upper member 51 and the lower member 52, semicircular arc grooves 51a and 52a with rectangular cross section are formed on the inner peripheral surfaces constituting the through hole 5a, which can engage with the flange portion 2b of the case 2. The case 2 is fixed to the device by connecting the upper member 51 and the lower member 52, with the groove 51a of the upper member 51 engaged with the upper half of the flange portion 2b in a state where the lower half of the flange portion 2b is engaged with the groove 52a of the lower member 52 fixed to the device to which the case 2 is to be attached.

[0030] A bearing 11 is disposed on the inner peripheral surface of the left end of the cylindrical portion 2a.

[0031] The first piston 3 is composed of an outer diameter side cylindrical portion 31, an inner diameter side cylindrical portion 32, a bottom portion 33, and an annular plate portion 34.

[0032] The outer diameter side cylindrical portion 31 has a larger diameter than the inner diameter side cylindrical portion 32 and is disposed on the outer diameter side away from the inner diameter side cylindrical portion 32 .

[0033] The inner diameter side cylindrical portion 32 is concentric with the outer diameter side cylindrical portion 31 when viewed in the axial direction. The inner diameter side cylindrical portion 32 is shorter than the outer diameter side cylindrical portion 31 in the axial direction.

[0034] The bottom portion 33 closes the right end of the outer diameter side cylindrical portion 31. The bottom portion 33 extends in the radial direction perpendicular to the central axis of the outer diameter side cylindrical portion 31.

[0035] The annular plate portion 34 connects the left end of the outer diameter side cylindrical portion 31 and the left end of the inner diameter side cylindrical portion 32. The annular plate portion 34 extends radially, perpendicular to the central axes of the outer diameter side cylindrical portion 31 and the inner diameter side cylindrical portion 32.

[0036] The space between the outer diameter side cylindrical portion 31 and the inner diameter side cylindrical portion 32 is closed on the left side by the annular plate portion 34, and on the right side communicates with the space on the inner diameter side of the inner diameter side cylindrical portion 32 through the gap between the inner diameter side cylindrical portion 32 and the bottom portion 33. The inner diameter side of the inner diameter side cylindrical portion 32 is open to the left.

[0037] The cylindrical portion 2a of the case 2 is inserted into the inner diameter side of the inner diameter side cylindrical portion 32. In other words, the first piston 3 is fitted onto the cylindrical portion 2a of the case 2 so as to be movable relative to it.

[0038] A holding member 6 that holds the elastic member 7 is connected to the bottom 33 of the first piston 3. The holding member 6 has an axially rectangular shape. An axially rectangular recess 6a that is recessed to the left is formed on the right surface of the holding member 6.

[0039] The elastic member 7 has an axially rectangular shape and is held in the recess 6a. The right surface of the elastic member 7 is located to the left of the right end surface of the holding member 6, so that the elastic member 7 abuts against the pressurized surface W1a of the acted-on body W1. In other words, the acted-on body W1 is placed in the recess 6a via the elastic member 7.

[0040] The second piston 4 is a stepped, bottomed cylindrical body. The left end of the cylindrical portion 4a of the second piston 4 is closed by a bottom portion 4b, and the right end is open to the right. A step 4c that protrudes outward is formed at the right end of the cylindrical portion 4a. Three annular recesses 4d to 4f that are recessed inwardly are provided axially spaced apart on the step 4c.

[0041] The middle annular recess 4e is shallower than the left annular recess 4d and the right annular recess 4f. A seal ring 9 is fitted into the annular recess 4f. A bearing 12 is fitted into the annular recess 4d. Note that no member such as a seal ring is fitted into the annular recess 4e.

[0042] The seal ring 9 may be an O-ring, but may also be an X-ring, lip seal, etc. The annular recess 4e has a gas reservoir function and an oil reservoir function.

[0043] The second piston 4 is inserted into the inner diameter side of the cylindrical portion 2a of the case 2. In other words, the second piston 4 is fitted into the cylindrical portion 2a of the case 2 so as to be movable relative to the cylindrical portion 2a.

[0044] A holding member 6' that holds an elastic member 7' is connected to the bottom 4b of the second piston 4. The elastic member 7' and the holding member 6' have substantially the same structures as the elastic member 7 and the holding member 6. The elastic member 7' is adapted to abut against the pressurized surface W2a of the acted-on body W2. In other words, the acted-on body W2 is disposed in the recess 6a' via the elastic member 7'.

[0045] The interior of the pressurizing device 1 configured as described above is surrounded by the case 2, the first piston 3, and the second piston 4, forming a connected internal space. This internal space is filled with high-pressure gas G. In other words, the internal space serves as a pressure accumulator 10, which is a cylindrical gas chamber. The volume of this pressure accumulator 10 changes as the first piston 3 and the second piston 4 move, as described below (see FIGS. 2 and 3).

[0046] Grease is held as a lubricating fluid in a space 15 formed between the case 2 and the second piston 4. This space 15 is in communication with the atmosphere through the left end, i.e., the bearing 11 side.

[0047] Moreover, grease is applied to the outer peripheral surface of the cylindrical portion 2a of the case 2.

[0048] Next, the contracted and expanded states of the pressure device 1 will be described with reference to Figures 2 and 3. As mentioned above, the case 2 is fixed to the mounting fixture 5 of the device to be mounted, and is immovable in the axial direction, i.e., the left-right direction.

[0049] 2, when the acted bodies W1 and W2 are closest to each other, the pressurizing device 1 is in a contracted state. In the contracted state of the pressurizing device 1, the annular plate portion 34 of the first piston 3 is not in contact with the mounting fixture 5. The seal ring 9 of the second piston 4 is maintained in contact with the inner circumferential surface of the cylindrical portion 2a.

[0050] When the pressurizing device 1 is in a contracted state, the first piston 3 and the second piston 4 partially overlap in the axial direction when viewed from the radial direction. Specifically, the first piston 3 overlaps by about 90% in the axial direction, and the second piston 4 overlaps by about 60% in the axial direction. In other words, the axial length of the pressurizing device 1 is compact.

[0051] When the pressurizing device 1 is in a contracted state, the volume of the pressure accumulator 10 is smallest within the stroke range of the first piston 3 and the second piston 4, and the gas G is in a most compressed state. The seal rings 8 and 9 prevent the gas G from moving to the space 15 and the outside (i.e., the space on the atmospheric side). Furthermore, the annular recesses 2d and 4e function as gas reservoirs, thereby effectively preventing leakage of the gas G.

[0052] The pressure of the gas G in the pressure accumulator 10 acts on the effective pressure-receiving surface of the first piston 3 and the effective pressure-receiving surface of the second piston 4. The effective pressure-receiving surface of the first piston 3 is the area obtained by subtracting the annular plate portion 34 from the bottom portion 33 of the first piston 3. The effective pressure-receiving surface of the second piston 4 is the area obtained by adding the bottom portion 4b of the second piston 4 and the right end face of the second piston 4. The effective pressure-receiving surface of the second piston 4 is smaller than the effective pressure-receiving surface of the first piston 3 by the right end face of the case 2.

[0053] The pressure of the gas G acting on the effective pressure receiving surfaces of the first piston 3 and the second piston 4 is transmitted to the acted upon bodies W1 and W2 as a stress dispersed by the holding members 6, 6' and elastic members 7, 7' of the same size. In other words, the acted upon bodies W1 and W2 can be pressurized in opposite axial directions with almost the same force.

[0054] That is, the first piston 3, the second piston 4, the holding members 6, 6', and the elastic members 7, 7' function as pressure transmitting bodies that transform the pressure in the pressure accumulating section 10 and transmit it to the acted-on bodies W1, W2.

[0055] 3, when the pressurized surface W1a of the acted body W1 is positioned at the rightmost position and the pressurized surface W2a of the acted body W2 is positioned at the leftmost position, the pressurizing device 1 is in an extended state in which the first piston 3 is moved to the rightmost position and the second piston 4 is moved to the leftmost position. In the extended state of the pressurizing device 1, the first piston 3 and the second piston 4 do not overlap in the axial direction. In other words, the first piston 3 and the second piston 4 are spaced apart in the axial direction. Furthermore, in the extended state of the pressurizing device 1, the step 4c of the second piston 4 does not contact the bearing 11.

[0056] When the pressurizing device 1 is in the extended state, the volume of the pressure accumulator 10 becomes the largest within the stroke range of the first piston 3 and the second piston 4, and the pressure of the gas G becomes low.

[0057] The movement of the first piston 3 and the second piston 4 from the contracted state of the pressure applying device 1 shown in Fig. 2 to the extended state of the pressure applying device 1 shown in Fig. 3 will be described. When the positions of the pressure applying surfaces W1a, W2a of the applied bodies W1, W2 move in directions away from each other, the first piston 3 and the second piston 4 simultaneously move in directions away from each other relative to the case 2. This prevents a sudden change in pressure.

[0058] In addition, since the pressure of the gas G is transmitted to the acted upon bodies W1 and W2 as stress dispersed by the retaining members 6, 6' and the elastic members 7, 7', the pressure of the gas G is prevented from dropping suddenly as the first piston 3 and the second piston 4 move.

[0059] In other words, the pressure of the gas G gradually decreases as the first piston 3 and the second piston 4 move, thereby reducing the change in the pressurizing force on the acted-on bodies W1, W2 within the stroke range of the first piston 3 and the second piston 4. Therefore, without the need to supply fluid from an external device such as an accumulator or pump, the acted-on bodies W1, W2 can be pressurized with a substantially constant force within the stroke range of the first piston 3 and the second piston 4, allowing the pressurizing device 1 to be configured compactly.

[0060] Furthermore, when the first piston 3 and the second piston 4 move from the extended state of the pressure device 1 in Figure 3 to the contracted state of the pressure device 1 in Figure 2, the pressure of the gas G increases as the first piston 3 and the second piston 4 move.

[0061] As described above, when the pressurizing device 1 is in a contracted state, the first piston 3 and the second piston 4 partially overlap in the axial direction, so that the axial length of the pressurizing device 1 can be made compact, and a large amount of expansion and contraction relative to the axial length of the pressurizing device 1 can be ensured. Therefore, the pressurizing device 1 of the first embodiment can be applied when the range of movement of the pressurized surfaces W1a, W2a of the acted bodies W1, W2 is large. In addition, the amount of gas G enclosed can be reduced.

[0062] In addition, since the first piston 3 and the second piston 4 on both sides of the axial direction move relative to each other with the case 2 fixed to the attached device via the flange portion 2b as a reference, the strokes of the first piston 3 and the second piston 4 are stable, and the acted-on bodies W1 and W2 on both sides can be pressurized stably.

[0063] Specifically, when the case is not fixed to the device to which it is attached, the other piston (the other piston and the acted-on body) initially acts as a fixed part, like the device to which it is attached, so one piston moves relative to the case. After the movement of one piston is completed, the other piston (the one piston and the acted-on body) then acts as a fixed part, like the device to which it is attached, so the other piston moves relative to the case. In other words, because the pair of pistons move in stages, when the other piston moves relative to the case, the pressure on the acted-on body changes suddenly.

[0064] On the other hand, in the pressure application device 1 of the first embodiment, the case 2 is fixed to the device to be attached via the flange portion 2b, and therefore the load acting on the cylindrical portion 2a of the case 2 is received by the mounting fixture 5, and as described above, the first piston 3 and the second piston 4 operate simultaneously relative to the case 2. In other words, the pressure applied to the acted-on bodies W1 and W2 changes linearly in accordance with the stroke amount of the pressure application device 1, and therefore a sudden change in the pressure applied to the acted-on bodies W1 and W2 is suppressed.

[0065] Furthermore, even if the amount of movement of the pressurized surfaces W1a, W2a differs, the first piston 3 and the second piston 4 will expand and contract correspondingly with the case 2 as the reference, so that the acted-on bodies W1, W2 on both sides can be pressurized stably.

[0066] Furthermore, the first piston 3 is fitted tightly against the outer peripheral surface of the fixed case 2, and the second piston 4 is fitted tightly against the inner peripheral surface of the fixed case 2, thereby suppressing relative tilt and radial relative movement between the case 2 and the first piston 3 and second piston 4, resulting in high sealing performance.

[0067] Furthermore, the flange portion 2b of the case 2 fixed to the mounting fixture 5 is provided at the end opposite the first piston 3 fitted onto the case 2, i.e., at the left end of the cylindrical portion 2a. This allows the first piston 3 to move leftward close to the flange portion 2b, i.e., close to the left end of the cylindrical portion 2a, ensuring a large amount of expansion and contraction of the pressurizing device 1.

[0068] Furthermore, when the pressure applying device 1 is in a contracted state, a gap is formed between the fixture 5 and the first piston 3, which prevents a sudden change in the pressure applied to the objects W1 and W2 due to contact between the fixture 5 and the first piston 3 during the contraction of the pressure applying device 1. Furthermore, when the pressure applying device 1 is in an extended state, a gap is formed between the step 4c of the second piston 4 and the bearing 11, which prevents a sudden change in the pressure applied to the objects W1 and W2 due to contact between the step 4c and the bearing 11 during the extension of the pressure applying device 1.

[0069] In addition, the flange portion 2b of the case 2 is engaged with the grooves 51a, 52a of the mounting fixture 5, and the minute clearance between the grooves 51a, 52a and the flange portion 2b absorbs vibrations from the mounted device and prevents the vibrations from being transmitted to the case 2.

[0070] Furthermore, the annular recess 2d stores grease applied to the outer peripheral surface of the cylindrical portion 2a of the case 2, thereby contributing to the lubrication of the stroke of the first piston 3.

[0071] Furthermore, the grease in the space 15 enters between the bearing 11 and the second piston 4, between the bearing 12 and the case 2, and between the annular recess 4e and the case 2, smoothing the relative movement between the second piston 4 and the case 2. The annular recess 4e stores the grease in the space 15, which contributes to the lubrication of the stroke of the second piston 4.

[0072] Furthermore, since the space 15 is in communication with the atmosphere, the pressure inside the space 15 can be prevented from increasing, and the strokes of the first piston 3 and the second piston 4 can be performed stably.

[0073] Furthermore, one seal ring 8 seals the gap between the case 2 and the first piston 3, and one seal ring 9 seals the gap between the case 2 and the second piston 4. In other words, since the number of seal rings 8, 9 is small, the sliding resistance between the case 2 and the first piston 3 and the sliding resistance between the case 2 and the second piston 4 are small, allowing the first piston 3 and the second piston 4 to stroke smoothly.

[0074] In this embodiment, the positions of the pressurized surfaces W1a, W2a of the acted bodies W1, W2 are moved simultaneously and by the same amount, but the pressurized surfaces W1a, W2a may move at different times or by different amounts. Even in such a case, the first piston and the second piston operate in accordance with the movement of the pressurized surfaces relative to the case.

[0075] Furthermore, the case 2 is not limited to being fixed to the device by engaging with the fixture 5, but may also be fixed to the device by welding or the like.

[0076] Next, a pressure device according to a second embodiment will be described with reference to Figures 4 and 5. Note that the description of the same configuration as in the first embodiment will be omitted.

[0077] As shown in FIG. 4 , the case 220 of the pressure device 200 of the second embodiment includes an outer cylindrical portion 221 , an inner cylindrical portion 222 , a bottom portion 223 , and an annular plate portion 224 .

[0078] The outer diameter side cylindrical portion 221 has a larger diameter than the inner diameter side cylindrical portion 222 and is disposed on the outer diameter side at a distance from the inner diameter side cylindrical portion 222. A breathing hole 221a is formed in the left end portion of the outer diameter side cylindrical portion 221.

[0079] The inner diameter side cylindrical portion 222 is concentric with the outer diameter side cylindrical portion 221 when viewed in the axial direction. The inner diameter side cylindrical portion 222 has approximately the same length as the outer diameter side cylindrical portion 221 in the axial direction.

[0080] The bottom portion 223 connects the left end of the outer diameter side cylindrical portion 221 and the left end of the inner diameter side cylindrical portion 222. The bottom portion 223 extends radially, perpendicular to the central axes of the outer diameter side cylindrical portion 221 and the inner diameter side cylindrical portion 222.

[0081] The annular plate portion 224 extends radially inward from the right end of the outer diameter side cylindrical portion 221. The inner circumferential surface of the annular plate portion 224 is slidable relative to the outer circumferential surface of the outer diameter side cylindrical portion 231 of the first piston 230.

[0082] A portion (not shown) of the case 220 is fixed to the device to which it is to be attached. The case 220 may be fixed by welding or the like, or may be fixed using a predetermined fastener.

[0083] A step 235 that protrudes outward is formed at the left end of the outer diameter side cylindrical portion 231 of the first piston 230. This step 235 is slidable along the inner circumferential surface of the outer diameter side cylindrical portion 221.

[0084] The step portion 235 is provided with two annular recesses 235a, 235b that are recessed in the inward radial direction and spaced apart in the axial direction. A seal ring 236 is fitted into the right annular recess 235a. The left annular recess 235b is shallower than the annular recess 235a, and does not have the seal ring 236 fitted into it. The annular recess 235b functions as an oil reservoir.

[0085] Grease is held in a space 216 surrounded by the outer diameter side cylindrical portion 221, the inner diameter side cylindrical portion 222, the bottom portion 223, and the first piston 230 in the case 220, similar to the space 215 surrounded by the case 220 and the second piston 240. The space 216 communicates with the atmosphere through a breathing hole 221 a.

[0086] Furthermore, a space 217 surrounded by the outer diameter side cylindrical portion 221 of the case 220, the annular plate portion 224, and the first piston 230 holds grease, similar to the spaces 215 and 216. The space 217 communicates with the atmosphere through a gap between the annular plate portion 224 and the outer diameter side cylindrical portion 231 of the first piston 230.

[0087] 4, when the pressurizing device 200 is in the contracted state, the step 235 of the first piston 230 is located to the right of the breathing hole 221a. That is, the breathing hole 221a is not blocked by the first piston 230, so it is possible to prevent the pressure in the space 216 from increasing. Similarly, the space 217 is in communication with the atmosphere, so it is possible to prevent the pressure in the space 217 from decreasing.

[0088] 5, the step portion 235 of the first piston 230 does not come into contact with the annular plate portion 224 of the case 220. This prevents a sudden change in the pressure applied to the acted-on bodies W1 and W2.

[0089] Furthermore, since the space 216 is in communication with the atmosphere through the breathing hole 221a, it is possible to prevent a decrease in the pressure within the space 216 when the pressurizing device 200 is in the extended state. Similarly, since the space 217 is in communication with the atmosphere, it is possible to prevent a rise in the pressure within the space 217.

[0090] Furthermore, since the space 216 is not in communication with the atmosphere except through the breathing hole 221a, the grease in the space 216 can be prevented from evaporating.

[0091] Similarly, the space 217 is not in communication with the atmosphere except for the gap between the annular plate portion 224 and the outer diameter side cylindrical portion 231 of the first piston 230, so that the grease in the space 217 can be prevented from evaporating.

[0092] Furthermore, since the first piston 230 is guided from the outer diameter direction and the inner diameter direction by the outer diameter side cylindrical portion 221 and the inner diameter side cylindrical portion 222 of the case 220, the stroke of the first piston 230 is stabilized.

[0093] Furthermore, seal rings 8, 236 are respectively arranged between the first piston 230 and the outer diameter side cylindrical portion 221 of the case 220, and between the first piston 230 and the inner diameter side cylindrical portion 222 of the case 220, so that the relative tilt and radial misalignment between the first piston 230 and the case 220 can be absorbed.

[0094] Next, a pressure device according to a third embodiment will be described with reference to Figures 6 and 7. Note that the description of the same configuration as in the first embodiment will be omitted.

[0095] 6, in the case 320 of the pressure device 300 of the third embodiment, the flange portion 320b is located closer to the center than the left end of the cylindrical portion 320a, which makes it easier to stabilize the holding state of the case 320 in the extended state.

[0096] 6, the first piston 330 is located to the right as compared to the configuration of Example 1. That is, the volume of the pressure accumulating section 310 is larger than that of Example 1.

[0097] 6 and 7, the volume of the pressure accumulator 310 changes between the contracted state of the pressure device 300 and the extended state of the pressure device 300. However, since the volume of the pressure accumulator 310 when the pressure device 300 is in the contracted state is larger than that of the first embodiment, it is possible to make the change in pressure in the pressure accumulator 310 relative to the stroke range of the pressure device 300 slow. In other words, it is possible to apply pressure to the acted bodies W1 and W2 with a substantially constant force within the stroke range of the pressure device 300.

[0098] Next, a pressure device according to a fourth embodiment will be described with reference to Figures 8 and 9. Note that the description of the same configuration as in the first embodiment will be omitted.

[0099] As shown in FIG. 8, a pressure device 400 according to the fourth embodiment is composed of a pair of upper and lower piston mechanisms 401 .

[0100] The piston mechanism 401 is mainly composed of a case 420 , a first piston 430 , and a second piston 440 .

[0101] The case 420 has a cylindrical portion 420a and a flange portion 420b as a fixing portion. The flange portion 420b protrudes radially outward from the left end of the cylindrical portion 420a. The flange portions 420b of the pair of cases 420 are integrally formed. The flange portions 420b are fixed to the device to which the case 420 is attached. The pair of upper and lower cylindrical portions 420a extend substantially parallel to the right from the flange portions 420b.

[0102] Although the fourth embodiment exemplifies a configuration in which the pair of cases 420 are integrally formed, the pair of cases 420 may be formed from separate members, and the flange portions 420b of the separate members may be connected to each other.

[0103] The first pistons 430 have the same shape as the first pistons 3 of the first embodiment, and are fitted onto the outer surfaces of the cylindrical portions 420a. The pair of first pistons 430 are arranged vertically spaced apart from each other.

[0104] A holding member 460 is fixed across the top and bottom to the right of the pair of first pistons 430. The holding member 460 holds an elastic member 470. Note that in the fourth embodiment, the first pistons 430 and the holding member 460 are formed as separate members and are connected to each other, but the first pistons 430 and the holding member 460 may be formed integrally.

[0105] The holding member 460 and the elastic member 470 are formed larger than those in the first embodiment, and are therefore suitable for applying pressure to the object W10 having a large pressure-receiving surface W10a.

[0106] The second piston 440 has substantially the same shape as the second piston 4 of the first embodiment, and is fitted into each cylindrical portion 420a.

[0107] A holding member 460' is fixed integrally across the top and bottom to the left side of the pair of second pistons 440. The holding member 460' holds an elastic member 470'. Note that, although the fourth embodiment exemplifies a form in which the second pistons 440 and the holding member 460' are integrally formed, the second pistons 440 and the holding member 460' may be formed as separate members and then connected to each other.

[0108] The holding member 460' and the elastic member 470' are formed larger than those in the first embodiment, and are therefore suitable for applying pressure to the object W20 having a large pressure-receiving surface W20a.

[0109] A communication passage 441 that communicates the internal spaces of the pair of second pistons 440 is formed between the holding member 460′ and the bottom portion 440b of each second piston 440. In other words, each piston mechanism 401 communicates with the same pressure accumulator 410.

[0110] This pressure device 400 operates between the contracted state shown in Fig. 8 and the extended state shown in Fig. 9. In this way, the holding member 460 and the elastic member 470, and the holding member 460' and the elastic member 470' are supported by the two piston mechanisms 401, so that the expansion and contraction operation of the pressure device 400 is stable.

[0111] Furthermore, since the pair of first pistons 430 face in the same axial direction and the pair of second pistons 440 face in the same axial direction, the pressure is not hindered between the pair of first pistons 430 or the pair of second pistons 440, and approximately the same pressure is applied to the acted-on body W10 from the pair of first pistons 430, and approximately the same pressure is applied to the acted-on body W20 from the pair of second pistons 440.

[0112] Furthermore, since the pair of piston mechanisms 401 communicate with the same pressure accumulator 410, the pair of piston mechanisms 401 can pressurize the acted bodies W10 and W20 with the same pressure force.

[0113] Furthermore, since the pair of piston mechanisms 401 are fixed to the attached equipment by the same flange portion 420b, the unity of each piston mechanism 401 is enhanced, relative positional deviation can be regulated, and the pressure applied to the acted-on bodies W10 and W20 can be stabilized.

[0114] In the fourth embodiment, the internal spaces of the second pistons 440 are connected to each other by the connecting passage 441, but the internal spaces of the first pistons may also be connected to each other by a connecting passage. Furthermore, for example, when the pressurized surface is large, a plurality of connecting passages may be provided to connect the internal spaces of the first pistons to each other and the internal spaces of the second pistons to each other.

[0115] Furthermore, the pair of piston mechanisms 401 do not necessarily have to be fixed to the device by the same flange portion 420b, but may be fixed to the device via separate fixing portions.

[0116] Next, a pressurizing device according to a fifth embodiment will be described with reference to Figures 10 and 11. Note that the description of the configuration that is the same as that of the fourth embodiment will be omitted.

[0117] As shown in FIG. 10, in a pressurizing device 500 of the fifth embodiment, a lower piston mechanism 501 and an upper piston mechanism 501' are oriented in opposite directions in the axial direction.

[0118] The lower piston mechanism 501 has a configuration substantially identical to that of the piston mechanism 401 of Example 4, with a separate retaining member 560' fixed to the bottom 540b of the second piston 540, and a separate retaining member 560 fixed to the bottom 533 of the first piston 530.

[0119] The upper piston mechanism 501' is oriented in the opposite direction to the piston mechanism 401 of the fourth embodiment. Specifically, a first piston 530' is fitted to the left side of a case 520', and a second piston 540' is fitted to the right side of the case 520'. A holding member 560' is fixed to a bottom 533' of the first piston 530'. Furthermore, a holding member 560 is fixed to a bottom 540b' of the second piston 540'.

[0120] The flange portion 520b' of the case 520' is provided at the right end portion of the cylindrical portion 520a'. The flange portion 520b' of the case 520' is located to the right of the flange portion 520b of the case 520. In other words, the lower case 520 and the upper case 520' are separated.

[0121] The lower second piston 540 and the upper first piston 530′ are in communication with each other through a radially extending communication pipe 517. In other words, the piston mechanisms 501 and 501′ are in communication with the same pressure accumulator 510.

[0122] This pressure device 500 operates between a contracted state shown in Fig. 10 and an extended state shown in Fig. 11. During operation, the second piston 540 and the first piston 530' move integrally relative to the cases 520, 520', and the first piston 530 and the second piston 540' move relative to the cases 520, 520' at approximately the same time.

[0123] Since the sum of the effective pressure receiving surface of the second piston 540 and the effective pressure receiving surface of the first piston 530' on which the pressure of the gas G in the pressure accumulator 510 acts is the same as the sum of the effective pressure receiving surface of the first piston 530 and the effective pressure receiving surface of the second piston 540', the acted upon bodies W10 and W20 on both axial sides can be pressurized with approximately the same force.

[0124] In addition, in this embodiment 5, the pair of piston mechanisms 501, 501' are not limited to being fixed to the attached device by separate flange portions 520b, 520b', but may be fixed to the attached device via the same fixing portion.

[0125] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0126] For example, in the first to fifth embodiments, the first piston and the second piston are shaped like a cylinder with a bottom, but they may be solid pistons.Furthermore, they may be pressure transmitting bodies that deform when subjected to pressure from the pressure accumulator, thereby transforming the pressure and transmitting it to the acting body.

[0127] Furthermore, in the above-described first to fifth embodiments, a gas is accumulated in the pressure accumulator, but a liquid such as oil or a mixture of a liquid and a gas may be sealed in the pressure accumulator.

[0128] In addition, in the above-described first to fifth embodiments, the movable members are disposed on both sides of the case so as to be relatively movable, but for example, one movable member may be fitted externally to one side of the case so as to be relatively movable, and the other movable member may be fitted externally to one side of the one movable member so as to be relatively movable.Furthermore, one movable member may be fitted internally to one side of the case so as to be relatively movable, and the other movable member may be fitted internally to one side of the one movable member so as to be relatively movable.

[0129] Furthermore, one movable member may be fitted externally onto one side of the case so as to be relatively movable, and the other movable member may be fitted externally onto the other side of the case so as to be relatively movable. Furthermore, one movable member may be fitted internally onto the other side of the case so as to be relatively movable.

[0130] Furthermore, in the first to fifth embodiments, the case is fixed to the device to which the device is attached, but the case does not have to be fixed to the device to which the device is attached.

[0131] The case may also be provided with a movement restricting portion that defines the stroke range of the pair of movable members.

[0132] In addition, in the above-described first to fifth embodiments, a holding member and an elastic member are disposed between the first and second pistons and the object to be acted upon, but the first and second pistons may directly pressurize the object to be acted upon without providing a holding member and an elastic member. In this case, the first and second pistons function as pressure transmitters. Furthermore, the first and second pistons may be fixed to the object to be acted upon.

[0133] REFERENCE SIGNS LIST 1 pressure device 2 case 2b flange portion (fixed portion) 3 first piston (one movable member, pressure transmitter) 4 second piston (other movable member, pressure transmitter) 5 attachment 6, 6' holding member (pressure transmitter) 7, 7' elastic member (pressure transmitter) 8, 9 seal ring 10 pressure accumulator G gas W1, W10 acted upon body W1a, W10a pressurized surface W2, W20 acted upon body W2a, W20a pressurized surface

Claims

1. A pressure device comprising a pressure accumulator and a pressure transmitter that transforms the pressure of the pressure accumulator and transmits it to an acted-on body, wherein the pressure transmitter has a pair of movable members that are movable axially relative to a case that constitutes part of the pressure accumulator, and at least a portion of the pair of movable members overlaps in the axial direction when viewed from the radial direction, at least when the pressure device is in a contracted state.

2. A pressure device according to claim 1, wherein the pair of movable members are arranged on both axial sides of the case, and the case has a fixing portion that is fixed to the device to which it is attached.

3. A pressure device as described in claim 2, wherein one movable member is fitted to the outer periphery of the case in a sealed manner so as to be movable relative to the outer periphery of the case, and the other movable member is fitted to the inner periphery of the case in a sealed manner so as to be movable relative to the inner periphery of the case.

4. The pressure device according to claim 3, wherein the fixed portion is provided at an end of the case opposite to the one movable member.

5. A pressure device according to any one of claims 2 to 4, wherein a gap is formed between said fixed portion and said one movable member when said pressure device is in a contracted state.

6. A pressure device according to claim 2, wherein the fixing portion is engaged with a fixed portion of the device to be attached.

7. The pressure device according to claim 1, wherein a plurality of pressure transmitting bodies are provided.

8. A pressure device according to claim 7, wherein the pressure transmitting bodies are oriented in the same axial direction.

9. A pressurizing device according to claim 7, wherein a plurality of said pressure transmitting bodies communicate with the same said pressure accumulator.

10. A pressure device according to claim 7, wherein a plurality of said pressure transmitting bodies are attached to the same said fixed portion.

11. The pressure device according to claim 7, wherein the pressure transmitting bodies are axially oriented in opposite directions.

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