Cylinder device

Abstract

A cylinder device (10) is provided with: a first cylinder chamber (26) having a first piston (20); a second cylinder chamber (28) having a second piston (22); a first rod (46) connected to the first piston (20); a second rod (48), a part of which overlaps the first rod (46) in the radial direction, and which protrudes from the cylinder (12); and a conversion mechanism (23) that converts a partial displacement of the first rod (46) in the axial direction into a displacement of the second rod (48) in the rotational direction and transmits another partial displacement of the first rod (46) in the axial direction as a displacement of the second rod (48) in the axial direction, the second piston (22) being connected to the second rod (48).

Description

Technical Field

[0001] The present invention relates to a cylinder device for displacing a rod in axial and rotational directions. Background Art

[0002] In automated production lines in factories, clamping cylinders (cylinder devices) are used to clamp objects. Such cylinder devices clamp objects by using the rotation of the push-out end of the rod and the axial linear motion toward the pull-in end of the rod.

[0003] The cylinder device used for clamping includes a conversion mechanism that converts the axial displacement of the piston into linear displacement and rotational displacement of the rod (Japanese Patent Application Laid-Open No. 2017-227223).

[0004] In an air cylinder device, it is sometimes necessary to increase the clamping force of a pressed object. In this case, a force-increasing mechanism is used in which a force-increasing piston is added to the air cylinder device and a rod is driven by the two pistons.

[0005] However, in conventional booster mechanisms, since the two pistons are driven with equal stroke lengths, there is a technical problem in that the overall length of the cylinder device becomes longer. Summary of the Invention

[0006] The purpose of the present invention is to solve the above-mentioned technical problems.

[0007] One aspect of the following invention relates to a cylinder device comprising: a first cylinder chamber having a first piston; a second cylinder chamber having a second piston; a first rod connected to the first piston; a second rod, a portion of which radially overlaps with the first rod and protrudes from a cylinder body; and a conversion mechanism that converts a displacement of a portion of the first rod in the axial direction into a displacement in the rotational direction of the second rod and transmits a displacement of another portion of the first rod in the axial direction as an axial displacement of the second rod, wherein the second piston is connected to the second rod.

[0008] The cylinder device of the above-described viewpoint can suppress the stroke length of the second piston within the stroke range of the second rod, and thus can suppress the overall length of the cylinder device.

[0009] The above-mentioned objects, features, and advantages will be readily understood through the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a cross-sectional view of the cylinder device according to the first embodiment.

[0011] Figure 2 yes Figure 1 A perspective view of the exploded state of the cylinder device.

[0012] Figure 3A Yes Figure 1 An explanatory diagram of the arrangement relationship between the first rod, the second rod, the first pin groove and the second pin groove of the cylinder device, Figure 3B This is a schematic diagram showing the positional relationship among the displacement switching groove, rotation groove, support pin, and guide pin of the second lever in a planar development.

[0013] Figure 4A yes Figure 1 A cross-sectional view of the cylinder device with the rod at the push-out end (push-out end position) is shown. Figure 4B Yes Figure 4A Schematic diagram of the position of the displacement switching groove of the support pin and the position of the rotation groove of the guide pin in the state.

[0014] Figure 5A yes Figure 1 A cross-sectional view of the cylinder device in a state where the rod of the cylinder device has completed rotation (rotation end position), Figure 5B Yes Figure 5A Schematic diagram of the position of the displacement switching groove of the support pin and the position of the rotation groove of the guide pin in the state.

[0015] Figure 6A yes Figure 1 A cross-sectional view of the cylinder device with the rod at the retracted end (retracted end position) is shown. Figure 6B Yes Figure 6A Schematic diagram of the position of the displacement switching groove of the support pin and the position of the rotation groove of the guide pin in the state.

[0016] Figure 7A is a cross-sectional view of a cylinder device according to a first modification of the first embodiment. Figure 7B It is a cross-sectional view of a cylinder device according to a second modified example of the first embodiment.

[0017] Figure 8 It is a perspective view of a cylinder according to a third modified example of the first embodiment.

[0018] Figure 9 It is a cross-sectional view of a cylinder device according to a second embodiment.

[0019] Figure 10 It is a cross-sectional view of a cylinder device according to a modified example of the second embodiment.

[0020] Figure 11A is a cross-sectional view of a cylinder device according to a third embodiment. Figure 11B yes Figure 11A A cross-sectional view of the cylinder device at the rotation end position.

[0021] Figure 12Ais a cross-sectional view of a cylinder device according to a first modified example of the third embodiment. Figure 12B It is a cross-sectional view of a cylinder device according to a second modified example of the third embodiment. DETAILED DESCRIPTION

[0022] (First embodiment)

[0023] Figure 1 The cylinder device 10 involved in the present embodiment shown is a clamping cylinder. The cylinder device 10 is used, for example, to fix a workpiece that is a processing object in an automated production line. The cylinder device 10 has a rod 14 protruding from a cylinder body 12. The rod 14 rotates at the push-out end (loosening end) and, after the rotation, moves linearly toward the pull-in end (clamping end). In addition, in this specification, the extension direction of the rod 14 is also referred to as the axial direction. In addition, in the axial direction, the direction toward the pull-in end is also referred to as the first direction, and the direction toward the push-out end is also referred to as the second direction.

[0024] like Figure 1 and Figure 2 As shown, the cylinder device 10 includes a cylinder body 12 (cylinder tube), a rod 14 , a rod-side cover 16 , a partition member 18 , a first piston 20 , a second piston 22 , and a conversion mechanism 23 .

[0025] The cylinder body 12 is a cylindrical component having a rectangular parallelepiped shape. The cylinder body 12 has a cylinder chamber 24 with a circular cross section inside. The cylinder chamber 24 extends in the axial direction. Figure 1 As shown, the cylinder chamber 24 is partitioned into a first cylinder chamber 26 and a second cylinder chamber 28 by a partition member 18. The end of the cylinder chamber 24 in the first direction is closed by an end wall 30 of the cylinder body 12. The cylinder body 12 is formed of a material such as metal or resin.

[0026] like Figure 2 As shown, the cylinder body 12 includes a first cylinder body 12a located in a first direction and a second cylinder body 12b located in a second axial direction. The first cylinder body 12a and the second cylinder body 12b are connected in the axial direction by a connecting rod 31 (tension bolt). The first cylinder body 12a has a first cylinder chamber 26 inside. The end of the first cylinder chamber 26 in the first direction is closed by an end wall 30 of the first cylinder body 12a.

[0027] The first cylinder body 12a includes a first fluid supply / discharge portion 32 and a second fluid supply / discharge portion 34 for supplying and discharging fluid to and from the first cylinder chamber 26. The first fluid supply / discharge portion 32 opens at or near the end of the first cylinder chamber 26 in the first direction. The first fluid supply / discharge portion 32 supplies and discharges pressurized fluid to the empty chamber 26a on the first direction side of the first cylinder chamber 26 via an external pipe. The second fluid supply / discharge portion 34 opens at or near the end of the second direction of the first cylinder chamber 26. The second fluid supply / discharge portion 34 supplies and discharges pressurized fluid to the empty chamber 26b on the second direction side of the first cylinder chamber 26 via an external pipe.

[0028] The first connecting flow path 36a branches off and extends from the second fluid supply and discharge portion 34. The first connecting flow path 36a is formed within the first cylinder 12a and extends in the second direction. The first connecting flow path 36a communicates with the second connecting flow path 36b of the second cylinder 12b at an end of the first cylinder 12a in the second direction.

[0029] like Figure 2 As shown, the second cylinder 12b has a through hole 24a constituting a part of the cylinder chamber 24. Figure 1 As shown, the end of the through hole 24a in the first direction is closed by the bulkhead member 18, and the end of the through hole 24a in the second direction is closed by the rod-side cover 16. A second cylinder chamber 28 is formed between the bulkhead member 18 and the rod-side cover 16. Furthermore, the second cylinder body 12b has a first port 38 and a second port 40 that communicate with the second cylinder chamber 28, and a second connecting flow path 36b. The first connecting flow path 36a and the second connecting flow path 36b constitute the connecting flow path 36 for supplying and discharging fluid to and from the second cylinder chamber 28.

[0030] The second connecting flow path 36b is a flow path extending axially within the second cylinder 12b. The first end of the second connecting flow path 36b is connected to the first connecting flow path 36a. The second end of the second connecting flow path 36b is connected to the second port 40.

[0031] The first port 38 opens at or near the end of the second cylinder chamber 28 in the first direction. In this embodiment, the first port 38 serves as a breathing hole that communicates with the outside, maintaining the empty chamber 28a on the first direction side of the second piston 22 at atmospheric pressure. The second port 40 communicates with the second fluid supply and exhaust portion 34 via the connecting flow path 36 (the first connecting flow path 36a and the second connecting flow path 36b). The second port 40 opens at or near the end of the second cylinder chamber 28 in the second direction. The second port 40 supplies and exhausts pressurized fluid to and from the empty chamber 28b on the second direction side of the second piston 22 via the second fluid supply and exhaust portion 34.

[0032] The second cylinder chamber 28 has an expanded diameter portion 42 near the end portion in the second direction. The expanded diameter portion 42 has a groove shape extending throughout the entire circumference of the second cylinder chamber 28. The inner diameter of the expanded diameter portion 42 is larger than the outer diameter of the second piston 22 and the gasket 22a. When the second piston 22 is located at the stroke end portion (the push-out end position) in the second direction, the expanded diameter portion 42 is located on the outer periphery of the second piston 22. The expanded diameter portion 42 is separated from the second piston 22 at the stroke end portion (the push-out end position) in the second direction. The gap between the expanded diameter portion 42 and the second piston 22 forms a leakage flow path 44 (refer to Figure 5A The expanded diameter portion 42 communicates with the empty chamber 28 a and the empty chamber 28 b on both sides of the second piston 22 at the pushing end position of the second piston 22 .

[0033] like Figure 1 As shown, the rod-side cover 16 has a T-shaped cross-section. The rod-side cover 16 has a cover hole 16a at its center. The rod 14 (second rod 48) is inserted through the cover hole 16a. The cover hole 16a supports the second rod 48 so that it can move in the axial and rotational directions. The rod-side cover 16 also includes a rod bushing 16b and a rod gasket 16c. The rod bushing 16b is disposed in the cover hole 16a. The rod bushing 16b slides on the outer peripheral surface of the rod 14 to guide the axial displacement of the rod 14. The rod gasket 16c prevents fluid leakage along the cover hole 16a.

[0034] like Figure 2 As shown, the partition wall member 18 is a cylindrical member having an outer peripheral surface 18a in close contact with the cylinder chamber 24. The partition wall member 18 is fixed to the cylinder body 12 by a set screw (not shown) so as to be non-displaceable in the axial and rotational directions.

[0035] like Figure 1 As shown, the bulkhead component 18 has a through hole 45 that penetrates axially at its center. The through hole 45 has a bulkhead hole 45a and a receiving hole 45b. The bulkhead hole 45a is located on the first direction side and has an inner diameter that is equal to or slightly larger than that of the first rod 46. The bulkhead hole 45a allows the first rod 46 to be inserted in a manner that is displaceable in the axial direction. A gasket is provided in the bulkhead hole 45a to prevent fluid leakage along the outer peripheral surface of the first rod 46. The receiving hole 45b is located on the second direction side of the bulkhead hole 45a and is connected to the bulkhead hole 45a. The receiving hole 45b has an inner diameter that is larger than the bulkhead hole 45a. The receiving hole 45b has an inner diameter that allows the second rod 48 to be accommodated so as to be displaceable in the axial direction. The second direction end of the receiving hole 45b opens toward the second cylinder chamber 28.

[0036] The bulkhead member 18 has a retaining hole 18b located near the end portion of the bulkhead member 18 in the second direction. The retaining hole 18b is a hole that penetrates the bulkhead member 18 in the radial direction and retains the support pin 56. The support pin 56 is formed as a cylindrical rod extending in a radial direction perpendicular to the axial direction. The bulkhead member 18 retains the support pin 56 in a manner that prevents rotational and axial displacement relative to the cylinder body 12.

[0037] The first piston 20 is disposed in the first cylinder chamber 26. The first piston 20 has a liner 20a on its outer periphery, which partitions the first cylinder chamber 26 into an empty chamber 26a on the first direction side and an empty chamber 26b on the second direction side. The first piston 20 is displaced axially along the first cylinder chamber 26 by the pressure difference between the empty chambers 26a and 26b.

[0038] The second piston 22 is disposed in the second cylinder chamber 28. The second piston 22 has a packing 22a on its outer periphery. The second piston 22 is displaced in the axial direction along the second cylinder chamber 28. The rod 14 is connected to the first piston 20 and the second piston 22.

[0039] The rod 14 includes a first rod 46 and a second rod 48. The first rod 46 is arranged along the central axis of the cylinder 12, and the end in the first direction is connected to the first piston 20. The first rod 46 displaces together with the first piston 20. The first rod 46 extends from the first piston 20 toward the second direction. The first rod 46 is inserted through the partition hole 45a of the partition member 18 and extends toward the second cylinder chamber 28. A portion of the first rod 46 is accommodated in the axial hole 60 of the cylindrical portion 48b of the second rod 48. The first rod 46 overlaps with the second rod 48 in the radial direction. The first rod 46 may also overlap with the second rod 48 in the radial direction from the outer peripheral side. The first rod 46 has a first pin groove 52 and a pin hole 54 in the overlapping portion with the second rod 48.

[0040] like Figure 1 and Figure 2 As shown, the first pin groove 52 penetrates the first rod 46 in a radial direction perpendicular to the axial direction. The first pin groove 52 extends in an axial slit-like manner when viewed from the side. The axial length of the first pin groove 52 is set to be equal to or longer than the stroke length of the first piston 20. Figure 1 As shown, a support pin 56 supported by the partition member 18 is inserted through the first pin groove 52. The support pin 56 is fixed in the axial and rotational directions relative to the cylinder body 12. Therefore, the rotational displacement of the first rod 46 is restricted by the support pin 56 and the first pin groove 52, and the first rod 46 can only be displaced in the axial direction.

[0041] The pin hole 54 is provided spaced apart from the first pin groove 52 in the first direction. The pin hole 54 radially penetrates the first rod 46. A guide pin 58 is inserted through the pin hole 54. The direction of penetration of the pin hole 54 is offset 90° from the direction of penetration of the first pin groove 52 in the circumferential direction. Therefore, the pin hole 54 allows the guide pin 58 to be inserted in a direction perpendicular to the support pin 56.

[0042] The second rod 48 is positioned on the second direction side of the first rod 46. The second rod 48 is positioned along the axial direction of the cylinder 12 and axially extends through the second cylinder chamber 28. The second rod 48 includes a rod portion 48a that protrudes from the cylinder 12 and a cylindrical portion 48b located on the first direction side of the rod portion 48a. The rod portion 48a is inserted through the cover hole 16a of the rod-side cover 16. The rod portion 48a protrudes from the rod-side cover 16.

[0043] The cylindrical portion 48b is located on the first direction side of the rod portion 48a. The cylindrical portion 48b is a cylindrical portion having a larger diameter than the rod portion 48a. The cylindrical portion 48b has an internal axial hole 60 with a circular cross-section. The axial hole 60 extends axially and opens at the end in the first direction. The axial hole 60 accommodates the first rod 46 so that it can be displaced axially. The second piston 22 is connected to the cylindrical portion 48b. In this embodiment, the second piston 22 and the second rod 48 are integrally connected and cannot be displaced in the rotational direction relative to the second rod 48.

[0044] like Figure 3A As shown, the cylindrical portion 48b has a displacement switching groove 62 for inserting the support pin 56 and a rotation groove 64 for inserting the guide pin 58. The displacement switching groove 62 and the rotation groove 64 penetrate from the outer peripheral surface of the cylindrical portion 48b to the shaft hole 60 in the radial direction. Figure 3B As shown, two displacement switching grooves 62 are provided at intervals of 180° in the circumferential direction. In addition, two rotation grooves 64 are also provided at intervals of 180° in the circumferential direction.

[0045] The displacement switching groove 62 includes an axial portion 62a extending in the axial direction and a circumferential portion 62b extending circumferentially from the first-direction end of the axial portion 62a. Specifically, the displacement switching groove 62 has an L-shape when viewed from the side. The axial length L1 of the axial portion 62a is set, for example, to half the stroke length of the first piston 20. The circumferential portion 62b extends over the angular range of the rotation angle (e.g., 90°) obtained by the rotational movement of the second rod 48.

[0046] The rotation groove 64 extends at an angle relative to the axial direction at a predetermined angle. The axial length L2 of the rotation groove 64 is set to 1 / 2 the stroke length of the first piston 20. The circumferential angular range of the rotation groove 64 extends within the angular range of the rotation angle determined by the rotational movement of the second rod 48. In other words, the circumferential angular range of the rotation groove 64 is the same as the angular range of the circumferential portion 62b of the displacement switching groove 62. However, the rotation groove 64 is positioned at a position circumferentially offset by 90° relative to the circumferential portion 62b. Furthermore, the rotation groove 64 is positioned apart from the displacement switching groove 62 in the first direction.

[0047] The conversion mechanism 23 comprises a support pin 56, a guide pin 58, a displacement switching groove 62, and a rotation groove 64. The support pin 56 is immovable in both the axial and rotational directions relative to the cylinder body 12. The support pin 56 is inserted into the displacement switching groove 62. The guide pin 58 is axially displaceable relative to the cylinder body 12, but not rotationally displaceable. The guide pin 58 is inserted into the rotation groove 64.

[0048] The displacement switching groove 62 and the rotation groove 64 are displaced in the axial direction and the rotation direction relative to the cylinder 12 together with the second rod 48. The displacement switching groove 62 and the rotation groove 64 convert a portion of the axial displacement of the guide pin 58 into a rotational displacement of the second rod 48. Furthermore, the displacement switching groove 62 and the rotation groove 64 convert another portion of the axial displacement of the guide pin 58 into an axial displacement of the second rod 48.

[0049] When the first piston 20 is located at the end portion in the first direction (the retracted end position), the support pin 56 and the guide pin 58 are arranged at Figure 3B That is, the support pin 56 is located at the end of the axial portion 62 a in the second direction, and the guide pin 58 is located at the end of the rotation groove 64 in the first direction.

[0050] The cylinder device 10 of the present embodiment is configured as described above, and its operation will be described below.

[0051] The cylinder device 10 performs Figure 1 The pull-in end position shown is Figure 4A The reset action is performed by connecting the first fluid supply and discharge section 32 to the pressurized fluid source 66 and the second fluid supply and discharge section 34 to the exhaust section 68. This causes the first piston 20 to be driven in the second direction and to stop at the second end of the first cylinder chamber 26. The second rod 48 is driven in the second direction by the first rod 46, and the second piston 22 is positioned at the second end of the second cylinder chamber 28 (the ejection end position).

[0052] In the ejection end position, the second rod 48 projects in the second direction and becomes Figure 1 The state is rotated 90° along the circumferential direction. Figure 4B As shown, the support pin 56 is located at the end of the circumferential portion 62b of the displacement switching groove 62. The guide pin 58 is located at the end of the rotation groove 64 in the second direction. The second piston 22 is located in the enlarged diameter portion 42 of the second cylinder chamber 28.

[0053] Next, the clamping action of the second rod 48 of the cylinder device 10 is performed. The clamping action includes the rotation action of the rod 14 at the push-out end and the linear pulling action of the rod 14 toward the pull-in end. Figure 5A As shown, the clamping operation is performed by operating the switching valve 70 to connect the exhaust port 68 to the first fluid supply and exhaust port 32 and the pressurized fluid source 66 to the second fluid supply and exhaust port 34. Pressurized fluid is supplied to the empty chamber 26b of the first cylinder chamber 26 via the second fluid supply and exhaust port 34, causing the first piston 20 to displace in the first direction. The first rod 46 displaces in the first direction along with the first piston 20.

[0054] As a result, the first piston 20 is Figure 4A The push-out end position Figure 5A During this period, the second rod 48 is rotated (rotated). Figure 5B As shown, displacement of the first rod 46 in the first direction causes the guide pin 58 to move in the first direction. Since the guide pin 58 maintains a constant circumferential position, the rotation groove 64 rotates to follow the guide pin 58 as the guide pin 58 moves in the first direction. As a result, the entire second rod 48 rotates -90° circumferentially, rotating the rod 14. Furthermore, axial displacement of the second rod 48 is prevented by the support pin 56 located on the circumferential portion 62b. Therefore, until the support pin 56 moves toward the axial portion 62a, the second rod 48 and the second piston 22 remain at their ends in the second direction and continue to rotate.

[0055] As the second rod 48 rotates, the second piston 22 rotates along with it. In this embodiment, the second piston 22 rotates within the expanded diameter portion 42. The expanded diameter portion 42 reduces frictional resistance during rotational movement of the second piston 22 and its gasket 22a. Consequently, the second rod 48 can rotate with less force. Furthermore, the expanded diameter portion 42 reduces wear on the rotation groove 64 and guide pin 58, which generate the rotational motion.

[0056] In addition, if Figure 5AAs shown, the expanded diameter portion 42 forms a leakage path 44 between the expanded diameter portion 42 and the outer periphery of the second piston 22, allowing fluid from the second port 40 to escape toward the empty chamber 28a. During the rotational motion of the second piston 22, the leakage path 44 prevents the generation of driving force from the second piston 22. Therefore, the expanded diameter portion 42 prevents wear of the support pin 56 and the circumferential portion 62b by preventing the generation of boost pressure during the rotational motion of the second piston 22. Providing such an expanded diameter portion 42 prevents wear of the conversion mechanism 23 and extends the life of the cylinder device 10.

[0057] Next, the rod 14 of the cylinder device 10 is pulled in a straight line. Figure 6A As shown, in this action, the second rod 48 is displaced in the first direction together with the first rod 46. Figure 6B As shown, the displacement of the first rod 46 in the first direction is transmitted to the second rod 48 via the guide pin 58 and the rotation groove 64. Furthermore, since the support pin 56 is located in the axial portion 62a of the displacement switching groove 62, it does not hinder the axial displacement of the second rod 48. Therefore, the second rod 48 begins to displace by being pulled in the first direction.

[0058] When the second rod 48 is displaced a predetermined distance in the first direction, the liner 22a of the second piston 22 moves past the expanded portion 42 toward the first direction of the expanded portion 42. As a result, the second piston 22 separates the second cylinder chamber 28 into a liquid- and air-tight manner. The fluid flowing in from the second port 40 increases the pressure in the empty chamber 28b relative to the pressure in the empty chamber 28a, generating a driving force in the first direction within the second piston 22. As a result, the second rod 48 is displaced in the first direction by the driving forces of the first piston 20 and the second piston 22. At this time, the rod 14 generates a greater driving force.

[0059] As described above, in the cylinder device 10 of this embodiment, since the second piston 22 is coupled to the second rod 48, the stroke range of the second piston 22 only needs to be within the stroke range of the second rod 48. Therefore, in this embodiment, the axial length of the second cylinder chamber 28 that accommodates the second rod 48 can be relatively short, and the overall length of the cylinder device 10 can be shortened compared to a case where the second piston 22 is coupled to the first rod 46.

[0060] (First Modification of the First Embodiment)

[0061] Figure 7A The second cylinder chamber 28 and the second piston 22 at the push-out end position of the cylinder device 10 according to the first modification are shown. In this modification, at the push-out end position, the opening position of the second port 40 of the second cylinder chamber 28 is Figures 1 to 6BThe second port 40 shown is offset toward the first direction. The second port 40 thus arranged can prevent the second piston 22 from generating a driving force for boosting during the rotational displacement of the rod 14 and prevent wear of the displacement switching groove 62.

[0062] Furthermore, in this variation, a V-shaped gasket is preferably used as the gasket 22a of the second piston 22. The V-shaped gasket is arranged with the top end of the V facing the first direction. The V-shaped gasket remains closed until pressure is applied to the empty chamber 28b on the second direction side. Therefore, even without the expanded diameter portion 42, frictional resistance during rotation of the second piston 22 can be suppressed. Therefore, in this variation, the expanded diameter portion 42 can be omitted from the second cylinder chamber 28.

[0063] In this modification, when the liner 22a of the second piston 22 is displaced toward the first direction relative to the second port 40, a driving force in the first direction is generated in the second piston 22. The cylinder device 10 of this modification does not require the enlarged diameter portion 42, thus simplifying the structure.

[0064] (Second Modification of the First Embodiment)

[0065] Figure 7B The present modification shown is similar to the first modification ( Figure 7A ). In this modified example, the second port 40 is located slightly further to the first direction than the top of the outer peripheral side of the gasket 22a. In this modified example, the gap between the gasket 22a and the second cylinder chamber 28 forms a leakage flow path 44, thereby preventing the generation of boost pressure when the second piston 22 rotates.

[0066] (Third Modification of First Embodiment)

[0067] like Figure 8 As shown, the cylinder device 10 of this modified example has an axial groove 72 connected to the expanded diameter portion 42 on the inner peripheral surface of the second cylinder chamber 28. The axial groove 72 constitutes a leakage flow path 44 that allows the fluid of the second port 40 to leak when the second piston 22 is located at the ejection end position. The cylinder device 10 of this modified example can prevent the generation of boost pressure during the rotational movement of the second piston 22. In addition, the example shown in the figure shows an example in which the expanded diameter portion 42 and the axial groove 72 are provided, but this modified example is not limited to this. It is also possible to provide the axial groove 72 in a manner connected to the second port 40 without providing the expanded diameter portion 42.

[0068] (Second embodiment)

[0069] Figure 9 The cylinder device 10A of the present embodiment shown in the figure is different from the cylinder device 10A in that it includes a second piston 22A that is rotatable relative to the second rod 48. Figure 1 The cylinder device 10 is different. In addition, Figure 9 In the cylinder device 10A, Figure 1 The same structures of the cylinder device 10 are marked with the same symbols, and their detailed descriptions are omitted.

[0070] The second piston 22A has a mounting hole 74 at its center, through which the second rod 48 can be inserted. The mounting hole 74 axially extends through the second piston 22A. The mounting hole 74 has a gasket mounting groove 76 and a stopper mounting groove 78 on its inner circumference. The gasket mounting groove 76 is formed near the axial center of the mounting hole 74 and accommodates a gasket 80. The gasket 80 prevents fluid leakage through the gap between the inner circumference of the second piston 22A and the cylindrical portion 48b.

[0071] The stopper mounting groove 78 is located at the end portion of the second piston 22A in the second direction. The stopper mounting groove 78 accommodates an annular stopper 82 and a fixing member 84. The stopper 82 and fixing member 84 engage with an engagement groove 86 formed on the outer circumferential surface of the second rod 48. The stopper 82 and fixing member 84 prevent axial displacement of the second piston 22A relative to the second rod 48.

[0072] The second piston 22A of this embodiment can rotate relative to the second rod 48 and does not follow the rotation displacement of the second rod 48 at the push-out end position. Therefore, it is not necessary to provide the enlarged diameter portion 42 (see Figure 1 The cylinder device 10A of this embodiment can prevent wear of the guide pin 58 and the rotation groove 64 even without providing the enlarged diameter portion 42, thereby simplifying the structure.

[0073] (Modification of the Second Embodiment)

[0074] like Figure 10 As shown, this modification has Figure 9 The second piston 22A shown in FIG. The second piston 22A of this modified example has a first liner 88 and a second liner 90 disposed axially offset on its outer periphery. As shown in the figure, when the second piston 22A is at the end of its stroke in the second direction (the ejection end position), the first liner 88 is disposed between the second port 40 and the empty chamber 28a, and the second liner 90 is disposed between the second port 40 and the empty chamber 28b.

[0075] When the second rod 48 is rotated, the first gasket 88 prevents leakage of fluid into the empty chamber 28a, while the second gasket 90 prevents leakage of fluid into the empty chamber 28b, thereby preventing the generation of a driving force for force amplification.

[0076] Therefore, the cylinder device 10A of this modification can suppress the consumption of the fluid and reduce the energy consumption by preventing leakage of the fluid through the second cylinder chamber 28 .

[0077] (Third embodiment)

[0078] Figure 11A and Figure 11B The second port 40B of the cylinder device 10B of the present embodiment shown is opened in the cover hole 16a of the rod side cover 16B. Figure 11A and Figure 11B In the cylinder device 10B, Figure 9 The same components as those in the cylinder device 10A are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0079] like Figure 11A As shown, the cylinder device 10B includes a rod-side cover 16B and a rotary valve 92. The rod-side cover 16B includes a second port 40B and a cover flow path 94. The cover flow path 94 is a portion formed by enlarging the inner diameter of the cover hole 16a and is located on the first direction side of the cover hole 16a. The inner diameter of the cover flow path 94 is larger than the outer diameter of the cylindrical portion 48b of the second rod 48. The end of the cover flow path 94 on the first direction side opens toward the second cylinder chamber 28 (empty chamber 28b).

[0080] The second port 40B is formed as a radially extending flow path formed inside the rod-side cover 16B. The second port 40B is arranged at a predetermined position in the circumferential direction of the cylinder body 12. The inner peripheral end of the second port 40B opens to the inner peripheral surface of the cover flow path 94. The rod-side cover 16B has a circumferential groove 41 on the outer periphery. The circumferential groove 41 is arranged at a position opposite to one end of the connecting flow path 36 and is connected to the connecting flow path 36. The circumferential groove 41 extends over the entire circumference of the rod-side cover 16B. The second port 40B is connected to the connecting flow path 36 via the circumferential groove 41.

[0081] The rotary valve 92 is a cylindrical component mounted on the cylindrical portion 48b of the second rod 48. The rotary valve 92 is located at the end of the cylindrical portion 48b in the second direction and is mounted on the outer circumference of the cylindrical portion 48b. The rotary valve 92 integrally displaces in the rotational and axial directions with the second rod 48. When the second rod 48 is in the push-out end position, the rotary valve 92 is housed in the cover flow path 94. The rotary valve 92 is in close contact with the inner circumference of the cover flow path 94, preventing communication between the second port 40B and the second cylinder chamber 28.

[0082] like Figure 11B As shown, the rotary valve 92 has a connecting groove 96 extending in the axial direction at a predetermined position in the circumferential direction. The connecting groove 96 of the rotary valve 92 is arranged at a position in the circumferential direction that coincides with the second port 40B at the rotation end position of the second rod 48. Figure 11A As shown, the rotary valve 92 closes the cap flow path 94. When the rotation of the rod 14 is completed, the rotary valve 92 is turned to Figure 11B As shown in the figure, at the end of the rotation, the second port 40B and the empty chamber 28b of the second cylinder chamber 28 are communicated with each other through the communication groove 96.

[0083] Therefore, the cylinder device 10B of the present embodiment can prevent the second piston 22A from generating a force increase during the rotational operation of the rod 14 , and can prevent wear of the displacement switching groove 62 and the support pin 56 .

[0084] (First Modification of the Third Embodiment)

[0085] like Figure 12A As shown, the cylinder device 10B of this modified example is provided with a second rod 48 having a step portion 98 and a rod side cover 16B having a cover flow path 94 closed by the second rod 48 instead of the rotary valve 92. Figure 11A The same structure as that of the cylinder device 10B is described.

[0086] like Figure 12A As shown, the rod-side cover 16B includes a cover flow path 94 and a second port 40B opening in the cover flow path 94. A gasket receiving groove 94a is formed in the cover flow path 94 on the first direction side relative to the opening of the second port 40B. A closing gasket 100 is mounted in the gasket receiving groove 94a.

[0087] The second rod 48 is provided with a stepped portion 98. The first-direction side of the stepped portion 98 forms a large-diameter portion 98a, which is connected to the cylindrical portion 48b. The large-diameter portion 98a has a diameter slightly smaller than that of the cap flow path 94. At the push-out end of the rod 14, the large-diameter portion 98a is inserted into the cap flow path 94. The outer circumferential surface of the large-diameter portion 98a is in close contact with the sealing gasket 100, thereby preventing communication between the second port 40B and the second cylinder chamber 28.

[0088] The second rod 48 has a small-diameter portion 98b on the second direction side of the step portion 98. The small-diameter portion 98b has an outer diameter that is sufficiently smaller than the inner diameter of the sealing gasket 100. When the second rod 48 is pulled in and the step portion 98 moves toward the first direction side relative to the cover flow path 94, the small-diameter portion 98b forms a flow path between the cover flow path 94 and the small-diameter portion 98b, through which fluid can flow.

[0089] exist Figure 12A In the push-out end position of rod 14 shown, the fluid in second port 40B is sealed by sealing gasket 100 and large-diameter portion 98a. Therefore, during the rotation of rod 14, second piston 22A does not generate a force-increasing driving force. Consequently, cylinder device 10B of this modified example can prevent wear of displacement switching groove 62 and support pin 56.

[0090] When the second rod 48 completes its rotational displacement and moves in the first direction, the step 98 moves toward the first direction relative to the cover flow path 94. As a result, the second port 40B communicates with the empty chamber 28b of the second cylinder chamber 28, supplying fluid to the empty chamber 28b. This enables the second piston 22A to generate a driving force for force amplification.

[0091] (Second Modification of the Third Embodiment)

[0092] The cylinder device 10B of this modified example is different from the conventional cylinder device 10B in that the sealing gasket 100 is arranged on the large diameter portion 98a side. Figure 12A The other points are different from the cylinder device 10B. Figure 12A In this modification, when the large diameter portion 98a of the second rod 48 moves toward the first direction relative to the cover flow path 94, fluid is supplied to the second cylinder chamber 28, causing the second piston 22A to generate a driving force for amplification.

[0093] The cylinder device 10B of this modified example plays the role of Figure 12A The same effect is achieved by the cylinder device 10B.

[0094] The above disclosure is summarized as follows.

[0095] One aspect relates to a cylinder device comprising: a first cylinder chamber having a first piston; a second cylinder chamber having a second piston; a first rod connected to the first piston; a second rod, a portion of which radially overlaps with the first rod and projects from a cylinder body; and a conversion mechanism that converts a displacement of a portion of the first rod in the axial direction into a displacement of the second rod in the rotational direction and transmits another displacement of the first rod in the axial direction as an axial displacement of the second rod, wherein the second piston is connected to the second rod.

[0096] The above-described cylinder device can shorten the stroke length of the second piston, thereby reducing the overall length of the second cylinder chamber and shortening the overall length of the cylinder device.

[0097] In the above-mentioned cylinder device, the conversion mechanism may be located between the first piston and the second piston. In this cylinder device, since the second piston is located at a position not affected by the stroke of the first piston, the stroke length of the second piston can be shortened.

[0098] In the above-mentioned cylinder device, the axial length of the second cylinder chamber may be shorter than the axial length of the first cylinder chamber. This cylinder device can reduce the size in the axial direction.

[0099] In the above-mentioned cylinder device, the second cylinder chamber may include an expanded diameter portion having an inner diameter larger than that of the second piston, so that the second piston at the ejection end position is separated from the inner circumferential surface of the second cylinder chamber. This cylinder device can suppress wear of the conversion mechanism by suppressing sliding resistance during rotational displacement of the second piston.

[0100] In the above-mentioned cylinder device, the expanded diameter portion may be connected to the empty chambers on both sides of the axial direction of the second piston at the pushing end position. This cylinder device can prevent the second piston from generating a driving force for force amplification during rotational displacement of the second piston, thereby preventing wear of the conversion mechanism.

[0101] The above-mentioned cylinder device may include a first port opening at an end portion of the second cylinder chamber in a first direction toward the retraction end position, and a second port opening at an end portion of the second cylinder chamber in a second direction toward the extension end position. The cylinder device can drive the second piston by supplying and discharging fluid between the first port and the second port.

[0102] In the above-mentioned cylinder device, the second port may open into the second cylinder chamber at a position offset in the first direction from the liner of the second piston relative to the ejection end position. This cylinder device can prevent the generation of a force-increasing driving force in the second piston during rotational displacement of the second piston, thereby preventing wear of the conversion mechanism.

[0103] In the above-mentioned cylinder device, the second cylinder chamber may have a leakage flow path that allows fluid supplied from the second port to the inner peripheral surface to escape toward the first direction relative to the second piston. This cylinder device can prevent the second piston from generating a driving force for force amplification during rotational displacement of the second piston, thereby preventing wear of the conversion mechanism.

[0104] In the above-mentioned cylinder device, the leakage flow path may be a groove extending along the axial direction on the inner peripheral surface of the second cylinder chamber. This cylinder device can prevent the second piston from generating a driving force for force amplification during rotational displacement of the second piston, thereby preventing wear of the conversion mechanism.

[0105] The above-mentioned cylinder device may include: a first fluid supply and discharge portion opening on the first direction side of the first cylinder chamber; and a second fluid supply and discharge portion opening on the second direction side of the first cylinder chamber, wherein the cylinder body has a connecting flow path connecting the second fluid supply and discharge portion and the second port. This cylinder device can supply and discharge fluid to and from the second port via the second fluid supply and discharge portion, thereby reducing the number of connected pipes.

[0106] The above-mentioned cylinder device may include: a first gasket provided on the outer periphery of the second piston, located on the first direction side relative to the second port at the ejection end of the second piston; and a second gasket provided on the outer periphery of the second piston, located on the second direction side relative to the second port at the ejection end of the second piston. This cylinder device can prevent fluid leakage at the ejection end and suppress consumption of pressurized fluid.

[0107] The above-mentioned cylinder device may include: a rod-side cover having a cover hole through which the second rod is inserted; a cover flow path formed by a gap between the cover hole and the second rod, fluidically connecting the second port and the second cylinder chamber; and a sealing gasket that closes the cover flow path at the end of the second rod's stroke in the second direction and opens the cover flow path to the second cylinder chamber when the second rod moves in the first direction. This cylinder device can prevent fluid leakage at the ejection end and suppress consumption of pressurized fluid.

[0108] The above-mentioned cylinder device may include: a rod-side cover having a cover hole through which the second rod is inserted; a cover flow path formed by a gap between the cover hole and the second rod, fluidically connecting the second port and the second cylinder chamber; and a rotary valve disposed in the cover flow path and rotating together with the second rod. When the second rod is at a predetermined angle, the rotary valve opens the cover flow path. This cylinder device can prevent fluid leakage at the ejection end and suppress consumption of pressurized fluid.

[0109] In the above-mentioned cylinder device, the second piston may be rotatably connected to the second rod. In this cylinder device, since the sliding resistance of the rotational displacement of the second rod is small, wear of the conversion mechanism can be effectively prevented.

[0110] In addition, the present invention is not limited to the above disclosure, and various structures can be adopted without departing from the gist of the present invention.

Claims

1. A cylinder device (10, 10A, 10B), characterized in that: have: a first cylinder chamber (26) having a first piston (20); a second cylinder chamber (28) having a second piston (22, 22A); a first rod (46) connected to the first piston; a second rod (48) having a portion radially overlapping with the first rod and projecting from the cylinder (12); as well as a conversion mechanism (23) that converts a portion of the axial displacement of the first rod into a rotational displacement of the second rod, and transmits another portion of the axial displacement of the first rod as an axial displacement of the second rod. The second piston is connected to the second rod.

2. The cylinder device according to claim 1, characterized in that The conversion mechanism is located between the first piston and the second piston.

3. The cylinder device according to claim 1, wherein: The axial length of the second cylinder chamber is shorter than the axial length of the first cylinder chamber.

4. The cylinder device according to claim 1, wherein: The second cylinder chamber has an expanded diameter portion (42) having an inner diameter larger than that of the second piston, so that the second piston at the ejection end position is separated from the inner peripheral surface of the second cylinder chamber.

5. The cylinder device according to claim 4, characterized in that The expanded diameter portion communicates with empty chambers (28a, 28b) on both sides of the second piston in the axial direction at the extrusion end position.

6. The cylinder device according to claim 1, wherein: have: a first port (38) opening at an end portion of the second cylinder chamber in a first direction toward a retracting end position; as well as A second port (40) is opened at an end portion of the second cylinder chamber in a second direction toward the ejection end position.

7. The cylinder device according to claim 6, characterized in that The second port opens in the second cylinder chamber at a position offset in the first direction from the liner (22a) of the second piston at the ejection end position.

8. The cylinder device according to claim 6, wherein: The second cylinder chamber has a leakage flow path (44) that allows the fluid supplied from the second port to the inner peripheral surface to escape toward the first direction side relative to the second piston.

9. The cylinder device according to claim 8, characterized in that The leakage flow path is a groove formed on the inner peripheral surface of the second cylinder chamber and extending in the axial direction.

10. The cylinder device according to claim 6, wherein: have: a first fluid supply and discharge portion (32) which opens on the first direction side of the first cylinder chamber; and a second fluid supply and discharge portion (34) which opens on the second direction side of the first cylinder chamber, The cylinder has a connecting flow path (36) connecting the second fluid supply and discharge portion and the second port.

11. The cylinder device according to claim 6, wherein: The second piston is rotatably connected to the second rod.

12. The cylinder device according to claim 10 or 11, characterized in that: have: a first liner (88) provided on the outer periphery of the second piston and located on the first direction side relative to the second port at the ejection end of the second piston; as well as A second gasket (90) is provided on the outer periphery of the second piston and is located on the second direction side relative to the second port at the ejection end of the second piston.

13. The cylinder device according to claim 10 or 11, characterized in that: have: a rod side cover (16, 16B), the rod side cover having a cover hole (16a) for the second rod to pass through; a cover flow path (94) formed through a gap between the cover hole and the second rod, connecting the second port and the second cylinder chamber in fluid communication; and A closing gasket (100) closes the cover flow path at the end of the second rod's travel in the second direction, and opens the cover flow path and the second cylinder chamber when the second rod moves in the first direction.

14. The cylinder device according to claim 10 or 11, characterized in that: have: a rod side cover having a cover hole for the second rod to be inserted through; a cover flow path formed by a gap between the cover hole and the second rod, connecting the second port and the second cylinder chamber in fluid communication; as well as A rotary valve (92) is arranged in the cover flow path and rotates together with the second rod. When the second rod is located at a predetermined angle, the rotary valve opens the cover flow path.

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