clamping device

Abstract

A simple structure of a clamping device is provided with a plurality of detection valves for detecting an operation state. A piston rod 10 is movably arranged in a housing 1 in the up and down direction. A first flow path 61 of detection compressed air formed in the housing 1 is provided with a first detection valve 62. A valve member 63 of the first detection valve 62 is operated by an operation portion 69 protruding radially from the outer peripheral wall of the piston rod 17. A second flow path 79 of detection compressed air formed in the housing 1 is provided with a second detection valve 80. A valve face 85 of the second detection valve 80 formed in the operation portion 69 can be engaged with a valve seat 84 formed in the housing 1.

Description

Technical Field

[0001] The present invention relates to a clamping device that fixes a clamping object to a worktable, robot, or the like by pressing the inner circumferential surface of a hole formed in the clamping object in a workpiece, mold, tool, or the like. More specifically, it relates to a clamping device equipped with a detection valve that detects the operating state of the clamping device. Background Technology

[0002] As such a clamping device, there is a conventional clamping device described in Patent Document 1 (Japanese Patent Application Publication No. 2014-008598). This conventional technology is configured as follows.

[0003] A piston is inserted into a cylinder bore formed within the housing, allowing it to move vertically. A piston rod protrudes integrally from the piston, and the lower end of a clamping rod is horizontally movable into a cylindrical bore formed at the upper end of the piston rod. A wedge is formed at the upper end of the clamping rod, and a clamping member engages with the wedge. The clamping member moves horizontally by moving the clamping rod vertically. When the clamping member is inserted into a workpiece's bore, it engages with the inner circumferential surface of the bore. Furthermore, a flow path for a pressure fluid for detection is formed within the housing. A detection valve is provided midway through this flow path. By moving the piston downwards from its upper limit position, the detection valve switches the flow path from a closed state to an open state. This detection valve is configured such that a valve member is vertically movable between the outer circumferential surface of the clamping rod and the inner circumferential surface of the cylinder bore. An operating part protrudes radially outwards from the outer circumferential wall of the clamping rod. The operating part faces the valve member at a predetermined interval, allowing it to engage with the valve member from above. The valve face formed on the upper part of the valve member engages with the valve seat formed within the cylinder bore. When the piston descends (overtravel) from its release position (upper limit position) beyond the locking position where the engaging member engages with the inner circumferential surface of the workpiece bore, the operating part of the piston rod engages with the valve member, subsequently causing the valve member to move downwards. This causes the valve face to separate from the valve seat, detecting valve opening. As a result, piston overtravel is detected using the detection valve.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-008598 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In conventional technology, the ability to reliably detect when the piston descends beyond the locking position (overtravel) using a detection valve is advantageous. However, it is desirable to have a detection valve capable of detecting when the piston moves to the release position, located in a different part of the housing than the aforementioned detection valve. In this case, it is possible to implement this by arranging two detection valves vertically, but this increases the number of components, thus increasing the overall size of the clamping device. Therefore, conventional clamping devices have room for improvement in terms of incorporating multiple detection valves for detecting the operating state and achieving a simpler structure.

[0009] The purpose of this invention is to provide a simple clamping device for detecting multiple detection valves that can detect their operating states.

[0010] Methods for solving problems

[0011] To achieve the above objectives, for example, Figures 1 to 3 , Figures 4 to 6 , Figure 7 As shown, the present invention configures a cylinder device having an action detection valve for detecting release state and overtravel state in the following manner.

[0012] Piston 16 is axially movable and inserted into cylinder bore 10 formed within housing 1. Output member 23 protrudes from piston 16 toward its axially forward end. Engaging member 39 engages with wedge 41 formed in output member 23. Movement of output member 23 toward the axial direction causes engagement member 39 to move in a direction intersecting the axial direction. Engaging member 39 is externally fitted into hole 46 for clamping object 45 and is capable of engaging with the inner circumferential surface of hole 46. A first flow path 61 for detection pressure fluid is formed within housing 1. A first detection valve 62 is provided at the midpoint of the first flow path 61. By moving piston 16 or output member 23 toward a predetermined position at the base end of the axial direction, the first detection valve 62 cuts off or opens the first flow path 61. A second flow path 79 for detection pressure fluid is formed within housing 1. A second detection valve 80 is provided at the midpoint of the second flow path 79. By moving the piston 16 or the output member 23 to a predetermined position on the axial front end side, the second detection valve 80 cuts off or opens the second flow path 79. The first detection valve 62 is composed of a cylindrical valve member 63, an operating part 69, a first valve seat 71, and a first valve face 72. The cylindrical valve member 63 is inserted in a sealing manner between the outer peripheral surface of the output member 23 and the inner peripheral surface of the cylinder bore 10 in a manner that allows it to move along the axial direction. Furthermore, the cylindrical valve member 63 faces the piston 16 or the output member 23 at a predetermined interval in the axial direction, such that it can abut against the piston 16 or the output member 23. The operating part 69, which protrudes from the outer peripheral wall of the output member 23 in a direction intersecting the axial direction, faces the valve member 63 at a predetermined interval in the axial direction, such that it can engage with the valve member 63. A first valve seat 71 is formed within the cylinder bore 10. The first valve face 72 formed on the valve member 63 can engage with the first valve seat 71. The second detection valve 80 is composed of a second valve seat 84 and a second valve face 85. The second valve seat 84 is formed within the cylinder bore 10. The second valve face 85, formed in the operating part 69, can engage with the second valve seat 84.

[0013] The present invention can achieve the following effects.

[0014] By utilizing the operating part that operates the valve member of the first detection valve described above to construct the valve member of the second detection valve, it is not necessary to have a separate valve member for the second detection valve. Therefore, the number of parts can be reduced, and the overall size of the clamping device can be kept to a smaller size corresponding to the fewer parts. Thus, a clamping device having two detection valves capable of detecting the operating state can be manufactured with a simple structure. Attached Figure Description

[0015] Figure 1This is a cross-sectional view showing the first embodiment of the present invention and the released state of the clamping device.

[0016] Figure 2 This is a cross-sectional view showing the locked state of the clamping device according to the first embodiment described above.

[0017] Figure 3 This is a cross-sectional view showing the overtravel state of the clamping device according to the first embodiment described above.

[0018] Figure 4 This is a cross-sectional view illustrating the second embodiment of the present invention and showing the released state of the clamping device.

[0019] Figure 5 This is a cross-sectional view showing the locked state of the clamping device according to the second embodiment described above.

[0020] Figure 6 This is a cross-sectional view showing the overtravel state of the clamping device according to the second embodiment described above.

[0021] Figure 7 This is a cross-sectional view showing the third embodiment of the present invention and the released state of the clamping device.

[0022] Figure 8 This is a cross-sectional view showing the fourth embodiment of the present invention and the released state of the clamping device.

[0023] Figure 9 This is a cross-sectional view showing the locked state of the clamping device according to the fourth embodiment described above.

[0024] Figure 10 This is a cross-sectional view showing the overtravel state of the clamping device according to the fourth embodiment described above.

[0025] Figure 11 This is a partial enlarged view of the clamping device of the fourth embodiment described above. Figure 11 A and Figure 11 B corresponds to respectively Figure 8 and Figure 9 .

[0026] Figure 12 This is a cross-sectional view illustrating the fifth embodiment of the present invention and showing the released state of the clamping device. Detailed Implementation

[0027] use Figures 1-3 Let me describe the first embodiment of the present invention. First, based on the shown released state... Figure 1 The structure of the clamping device described above will be explained.

[0028] The housing 1 of the clamping device is inserted into the mounting hole formed in the worktable T of the machine tool and bolted to the worktable T. The housing 1 comprises a lower housing 3 and an upper housing 4. The lower half of the lower housing 3 is inserted into the mounting hole of the worktable T in a sealed manner. The upper half of the lower housing 3 protrudes upward from the worktable T and is fixed to the worktable T by a plurality of bolts (not shown). The upper housing 4 is inserted into the mounting hole 6 formed in the upper part of the lower housing 3 in a vertical direction and bolted to the bottom of the mounting hole 6.

[0029] A cylinder bore 10 is formed in the lower housing 3 along the vertical direction. This cylinder bore 10 has a first bore 11, a second bore 12, a third bore 13, and a fourth bore 14, with their diameters decreasing sequentially from the lower side. A piston 16 is inserted into the first bore 11 in a sealed manner, allowing it to move vertically (axially). A piston rod 17 protrudes upward from the piston 16 and is inserted into the fourth bore 14 through the second bore 12 and the third bore 13, also in a sealed manner, allowing it to move vertically. A cylindrical portion 18 is formed on the upper part of the piston rod 17, and a clamping rod 20 is inserted into the cylindrical bore 19 of this cylindrical portion 18, allowing it to move horizontally. A protrusion 21 protrudes radially inward from the inner peripheral wall of the cylindrical portion 18. By positioning the protrusion 21 to face the flange portion 22, which protrudes radially outward from the lower part of the clamping rod 20, from above, the clamping rod 20 is prevented from being pulled upward from the cylinder hole 19 of the piston rod 17. Here, in this embodiment, the output member 23 is constituted by the piston rod 17 and the clamping rod 20.

[0030] A locking chamber 26 is formed on the upper side of the piston 16, and a release chamber 27 is formed between the piston 16 and the bottom wall of the mounting hole of the worktable T. A locking supply and discharge path 28 communicating with the locking chamber 26 is formed in the housing 1. Therefore, pressurized oil from a pressure oil source is supplied to the locking chamber 26 through the locking supply and discharge path 28, and the pressurized oil in the locking chamber 26 is discharged to the outside through the supply and discharge path 28. In addition, a release supply and discharge path 29 is formed on the bottom wall of the mounting hole of the worktable T. Therefore, pressurized oil from a pressure oil source is supplied to the release chamber 27 through the supply and discharge path 29, and the pressurized oil in the release chamber 27 is discharged to the outside through the supply and discharge path 29.

[0031] A receiving hole 32 communicating with the aforementioned cylinder bore 10 is formed within the upper housing 4. A cylindrical cover member 33 is movably inserted into the receiving hole 32 relative to the housing 1 in both the horizontal and vertical directions. The upper half of the cover member 33 protrudes upward from the upper surface of the upper housing 4. A flange portion 34 is formed circumferentially at the lower part of the cover member 33, protruding radially outward. The upper surface of the flange portion 34 faces the top wall of the receiving hole 32 from below in a way that allows it to abut against the cover member 33, preventing it from falling out of the receiving hole 32.

[0032] The clamping rod 20 can be inserted into the cylindrical hole 35 of the cover member 33 in a vertical direction. Two support holes 36 extend radially through the peripheral wall of the cover member 33, and the engaging member 39 can be inserted into each support hole 36 in a movable manner along these holes. On the inner sidewall of the engaging member 39, the receiving surface 40 is formed to taper towards the front end (upwards). Furthermore, on the sidewall of the upper end of the clamping rod 20, the wedge surface (wedge portion) 41 is formed to thicken towards the front end (upwards) (away from the axis), and this wedge surface 41 engages with the receiving surface 40 of the engaging member 39 from above.

[0033] An engaging portion 42 is formed on the upper half of the outer side wall of the engaging member 39. Multiple protrusions are formed in the engaging portion 42 in a vertical direction, extending horizontally. These protrusions are capable of engaging with… Figure 2 The inner peripheral wall of the hole 46 of the workpiece (clamping object) 45 shown is engaged.

[0034] Furthermore, a mounting groove 43 is formed horizontally on the lower half of the outer side wall of the aforementioned engaging member 39, and a mounting groove 49 is also formed on the outer peripheral wall of the cover member 33, corresponding to the height position of the mounting groove 43 of the engaging member 39. An elastic ring 50 is mounted across the mounting groove 43 of the engaging member 39 and the mounting groove 49 of the cover member 33. The elastic force of the elastic ring 50 applies force to the engaging member 39 radially inward toward the cover member 33. In this embodiment, the elastic ring 50 is made of rubber, but it is not limited to this and may also be made of resin, a metal spring, or the like.

[0035] A spring receiving member 51 and a push spring 52 are inserted into the receiving hole 32 and below the cover member 33. The lower end of the push spring 52 is supported on the upper surface of the lower housing 3, and the upper end of the push spring 52 is supported on the top surface of the receiving hole 32 via the spring receiving member 51 and the flange portion 34 of the cover member 33. Therefore, the push spring 52 exerts a force upward on the cover member 33 relative to the lower housing 3. In this embodiment, the push spring 52 and the spring receiving member 51 constitute a support mechanism 53 that pushes the engaging member 39 upward with a predetermined force. Furthermore, the support mechanism 53 is not limited to the one described above, and the support mechanism of the second embodiment described later may also be used.

[0036] A dustproof ring 54 is fitted to the upper part of the inner peripheral wall of the aforementioned receiving hole 32. The front end 56 of the dustproof ring 54 engages with the outer peripheral surface of the cover member 33 and the outer side wall of the engaging member 39. The dustproof ring 54 is used to prevent foreign objects such as chips from entering the interior of the housing 1 through the gap between the cover member 33 and the housing 1, and the gap between the engaging member 39 and the housing 1. In addition, the radially inward elastic force of the dustproof ring 54 applies force to the clamping rod 20, the engaging member 39, and the cover member 33 in a radially inward direction toward the axis of the cylinder bore 10.

[0037] A portion (or all) of the upper end face of the upper housing 4 constitutes a seating surface (seat portion) 57, on which the workpiece 45 can be placed. An outlet 58 is provided on the seating surface 57, and a supply path 59 communicating with the outlet 58 is formed within the housing 1. Therefore, compressed air for seating detection from a compressed air source (pressure fluid source) is ejected from the outlet 58 via the supply path 59.

[0038] In the clamping device of this embodiment, a first flow path 61 for supplying compressed air (pressure fluid) for detecting the operation state is provided inside the housing 1. A first detection valve 62 is provided at the middle of this first flow path 61. This first detection valve 62 detects the situation where the piston 16 and the output member 23 descend beyond a predetermined distance in the locked position (overtravel state in the operation state), and so on. Figure 1 It is constructed as shown in the following manner.

[0039] The cylindrical valve member 63 is sealed by an outer sealing member 64 and an inner sealing member 65, and is inserted between the outer peripheral surface of the piston rod 17 and the inner peripheral surface of the second hole 12 of the cylinder bore 10 in a vertical (axial) manner. Furthermore, a retaining ring 67 is fitted into the mounting groove 66 formed in the lower part of the inner peripheral wall of the second hole 12 to prevent the valve member 63 from falling downwards from the second hole 12. A locking chamber 26 is formed between the valve member 63 and the piston 16. Additionally, a first valve chamber 68 is formed on the upper side of the valve member 63.

[0040] The lower surface of the valve member 63 can engage with the upper surface of the piston 16. Furthermore, the inner circumferential portion of the valve member 63 is formed such that its height is lower than that of its outer circumferential portion. The lower surface of the annular operating portion 69, which protrudes radially outward from the outer circumferential surface of the piston rod 17, can engage with the upper surface of the inner circumferential portion of the valve member 63. The upper surface of the outer circumferential portion of the valve member 63 can abut against the stepped portion (top surface of the second hole) 70 formed between the second hole 12 and the third hole 13. Therefore, when the piston 16 descends from the upper limit position to the lower limit position, the operating portion 69 engages with the valve member 63 at an intermediate position, causing the valve member 63 to descend to the engagement position between the valve member 63 and the retaining ring 67. Additionally, when the piston 16 moves from the lower limit position to the upper limit position, the piston 16 engages with the valve member 63 at an intermediate position, and then the valve member 63 rises to the engagement position between the valve member 63 and the stepped portion 70 (upper limit position).

[0041] An annular first valve seat 71 is formed on the annular stepped portion 70 between the second hole 12 and the third hole 13 of the aforementioned cylinder bore 10. A first valve surface 72 abutting against the first valve seat 71 is formed on the upper surface of the outer peripheral portion of the valve member 63. By engaging the first valve surface 72 with the first valve seat 71, the first valve chamber 68 is divided into a first inlet chamber 73 on the outer peripheral side and an outlet chamber 74 on the inner peripheral side.

[0042] A first supply path 75, communicating with the first inlet chamber 73, is formed within the housing 1 and opens to the inner peripheral surface of the second hole 12. Therefore, compressed air (pressure fluid) from a compressed air source (pressure fluid source) is supplied to the first inlet chamber 73 of the first valve chamber 68 via the first supply path 75. The supply path 59 branches off midway from the first supply path 75. Furthermore, a discharge path 76, communicating with the outlet chamber 74, is formed within the housing 1 and opens to the inner peripheral surface of the third hole 13. Therefore, compressed air within the first valve chamber 68 is discharged to the outside of the housing 1 via the discharge path 76. Here, in the clamping device of this embodiment, the first flow path 61 is composed of the first supply path 75, the first valve chamber 68 composed of the first inlet chamber 73 and the outlet chamber 74, and the discharge path 76.

[0043] In the clamping device of this embodiment, in order to detect an operating state different from the overtravel described above, a second flow path 79 for supplying compressed air (pressure fluid) for operating state detection is provided inside the housing 1. A second detection valve 80 is provided at the middle of this second flow path 79. This second detection valve 80 detects the situation where the piston 16 and the output member 23 rise to near the release position (the release state in the operating state), and so on. Figure 1 It is constructed as shown in the following manner.

[0044] A mounting groove is formed circumferentially on the inner peripheral wall of the third hole 13 of the cylinder bore 10, and an annular sealing member 81 is mounted in the mounting groove. The upper surface of the sealing member 81 is supported from above by a step portion (top surface of the third hole) 82 formed between the third hole 13 and the fourth hole 14 of the cylinder bore 10. Furthermore, the upper surface of the operating portion 69 of the piston rod 17 can engage with the sealing member 81. Therefore, near the upper limit position when the piston 16 moves from the lower position toward the upper limit position, firstly, the operating portion 69 engages with the sealing member 81, slightly flattening the sealing member 81. Then, the piston 16 is supported by the step portion 70 via the valve member 63. Therefore, when the piston 16 moves to the upper limit position and the clamping device is released, the second detection valve 80 reliably closes, and the first detection valve 62 reliably closes. Furthermore, in this embodiment, the sealing member 81 is made of rubber, but is not limited to this; it can also be a resin or metal ring. Furthermore, the sealing member 81 is configured to be fitted into the mounting groove of the third hole 13, but is not limited thereto. For example, it may be configured such that the mounting groove is formed into an annular shape on the upper part of the operating portion 69 of the piston rod 17 and the sealing member 81 is fitted into the mounting groove.

[0045] A mounting groove is formed circumferentially on the inner peripheral wall of the fourth hole 14 of the cylinder bore 10. An O-ring, serving as a sealing member, is mounted in this mounting groove. An annular space is formed between the inner peripheral surface of the fourth hole 14 and the outer peripheral surface of the piston rod 17 by the O-ring and the valve member 63. This annular space is used to construct the second valve chamber 83.

[0046] An annular second valve seat 84 is formed within the second valve chamber 83 and on the lower surface of the sealing member 81. Furthermore, an annular second valve surface 85 is formed on the upper surface of the operating portion 69 of the piston rod 17, and this second valve surface 85 can engage with the second valve seat 84. By engaging the second valve surface 85 with the second valve seat 84, the second valve chamber 83 is divided into a second inlet chamber 86 on the outer periphery and an outlet chamber 74 on the inner periphery. Additionally, a second supply path 87 is formed in the housing 1, opening into the inner periphery of the fourth hole 14. Compressed air from a compressed air source is supplied to the second valve chamber 83 through this second supply path 87. The compressed air in the second valve chamber 83 is discharged to the outside of the housing 1 through the outlet chamber 74 and the discharge path 76. Here, in the clamping device of this embodiment, the second flow path 79 is composed of the second supply path 87, the second valve chamber 83 consisting of the second inlet chamber 86 and the outlet chamber 74, and the discharge path 76. Furthermore, in the clamping device of this embodiment, the second detection valve 80 and the first detection valve 62 share an outlet chamber 74, but it is not limited to this. The outlet chamber of the second detection valve 80 may be formed in a different location than the outlet chamber 74 of the first detection valve 62, and the discharge path and discharge path 76 connected to the outlet chamber of the second detection valve 80 may be independently provided in the housing 1.

[0047] like Figures 1-3 As shown, the clamping device operates in the following manner.

[0048] exist Figure 1 In the clamping device in the released state shown, pressurized oil is discharged from the locking chamber 26, and pressurized oil from the pressurized oil source is supplied to the release chamber 27. The pressurized oil in the release chamber 27 moves the clamping rod 20 to the upper limit position via the piston 16 and piston rod 17.

[0049] In the released state of the clamping device, the piston 16 is received by the stepped portion 70 of the housing 1 via the valve member 63. As a result, the first valve surface 72 of the valve member 63 engages with the first valve seat 71, causing the first detection valve 62 for overtravel detection to close.

[0050] Furthermore, when the clamping device is in the released state, the piston rod 17 moves to the upper limit position. Therefore, the second valve face 85 of the operating part 69 of the piston rod 17 engages with the second valve seat 84, causing the second detection valve 80 for release detection to close.

[0051] In the aforementioned released state, the workpiece (clamping object) 45 is lowered from above the clamping device using some conveying component, such as a robot, or by the workpiece's own weight. This causes the hole 46 of the workpiece 45 to engage the cover member 33 and the locking member 39. Next, the lower surface of the workpiece 45 is supported by the seating surface 57 of the housing 1. At this time, the lower surface of the workpiece 45 covers the nozzle 58 for seating detection. Additionally, as described above, the first detection valve 62 for overtravel detection also closes. Therefore, the pressure of the compressed air in the supply path 59 supplying compressed air to the nozzle 58 and the compressed air in the first supply path 75 connected to the supply path 59 exceeds a preset value. This increased pressure is detected by a pressure switch (or pressure sensor) not shown. As a result, based on the pressure of the first detection valve 62 and the compressed air in the supply path 59, it is detected that the workpiece 45 is placed on the seating surface 57 and is not in an overtravel state where the piston 16 or the like has fallen beyond the locked position.

[0052] When the above clamping device is removed Figure 1 The release state towards Figure 2 When switching to the locked state, the pressure oil in the release chamber 27 is discharged, and pressure oil is supplied to the locking chamber 26. This causes the piston 16, piston rod 17, and clamping rod 20 to descend toward the locked position relative to the cover member 33 and engaging member 39, which are held in the upper limit position by the force of the push spring 52. At this time, the piston rod 17, formed on the second valve face 85 of the operating part 69, separates from the second valve seat 84. Therefore, the compressed air in the second inlet chamber 86 is discharged to the outside through the outlet chamber 74 and the discharge path 76, and the pressure of the compressed air in the second inlet chamber 86 decreases. This pressure decrease is detected using a pressure sensor (or pressure switch, not shown). As a result, the second detection valve 80 can detect that the piston 16, etc., have moved downward from the release position (upper limit position). Next, by pressing the wedge face 41 of the clamping rod 20 against the receiving face 40 of the engaging member 39, the clamping rod 20 pushes the engaging member 39 radially outward. In this way, the engaging portion 42 of the engaging member 39 engages with the inner circumferential surface of the hole 46 in the workpiece 45. At this time, the clamping rod 20 descends by slightly compressing the push spring 52 via the engaging member 39, the cover member 33, and the spring receiving member 51. As a result, the workpiece 45 is forcefully pressed against the seating surface 57 of the upper housing 4.

[0053] exist Figure 2In the locked state of the clamping device shown, the operating part 69 of the piston rod 17 is separated from the valve member 63 by a predetermined distance upwards, and this operating part 69 does not operate the valve member 63. Therefore, the state in which the valve member 63 is raised to the upper limit position by the pressure of the pressurized oil supplied to the locking chamber 26 is maintained. Consequently, the first valve face 72 engages with the first valve seat 71, and the first detection valve 62 closes. In addition, the state in which the lower surface of the workpiece 45 blocks the nozzle 58 of the housing 1 is maintained. Therefore, the state in which the pressure of the compressed air in the first supply path 75 exceeds a predetermined pressure is maintained.

[0054] Furthermore, when the clamping device is removed from the above... Figure 2 The locked state to Figure 1 When switching to the release state, the pressure oil in the locking chamber 26 is discharged, and pressure oil is supplied to the release chamber 27. Thus, the clamping device switches to the release state in a sequence that is substantially the reverse of the locking action described above.

[0055] In the above-mentioned clamping device, such as Figure 3 As shown, due to the insertion of a workpiece 45A with an aperture larger than intended, the piston 16 may sometimes descend beyond the aforementioned locking position (overtravel). In such cases, the clamping device operates as follows.

[0056] With the workpiece 45A, having an excessively large bore 46A, placed on the seating surface 57 of the clamping device, the clamping device is locked. This causes the engaging member 39 to be held in its upper limit position by the force of the push spring 52, while the wedge surface 41 of the clamping rod 20 pushes against the receiving surface 40 of the engaging member 39. This causes the clamping rod 20 to push the engaging member 39 radially outward (excessively enlarging its diameter). At this point, the engaging member does not abut against the inner peripheral wall of the bore 46A, which is excessively large compared to the intended size, and the clamping rod 20 descends beyond the intended locking position. This causes the operating portion 69 of the piston rod 17 to engage with the valve member 63 while the inner peripheral surface of the bore 46 of the workpiece 45 is not engaged with the engaging portion 42 of the engaging member 39. Afterward, the operating portion 69 causes the valve member 63 to descend. At this time, the first valve face 72 of the valve member 63 separates from the first valve seat 71, and the compressed air in the first inlet chamber 73 of the first valve chamber 68 is discharged to the outside of the housing 1 through the outlet chamber 74. Therefore, the pressure of the compressed air in the first inlet chamber 73 decreases, and this pressure decrease is detected using a pressure sensor (or pressure switch, not shown). Thus, based on the detection result of the pressure decrease, an overtravel state is detected where the piston 16 has descended beyond the aforementioned locking position. Next, the valve member 63 is received from below by the retaining ring 67 fitted into the first hole 11 of the cylinder bore 10, and the descent of the valve member 63 and the piston rod 17, etc., stops.

[0057] In addition to the case where a clamping device is used to clamp the workpiece 45A, which has a hole diameter that is larger than intended, there is also the possibility of it becoming... Figure 3 Such an overtravel condition. For example, the following situation: when the workpiece 45 is locked in a clamping state (refer to...) Figure 2 Due to metal fatigue, etc., the clamping rod 20 may break at its midpoint height. Additionally, if sufficient friction cannot be generated between the protrusion of the engaging portion 42 of the engaging member 39 and the inner circumferential surface of the workpiece 45, the protrusion may slide and descend on the inner circumferential surface of the workpiece 45. Furthermore, the clamping device may perform a clamping operation even when a portion of the engaging member 39 is damaged due to a collision with a peripheral machine. Even in these cases, similar to the aforementioned case of the workpiece 45A with an excessively large aperture 46A, the overtravel state of the clamping device is detected using the first detection valve 62 for overtravel detection.

[0058] The first embodiment described above can offer the following advantages.

[0059] The valve member of the second detection valve 80 is constructed using the operating part 69 that operates the valve member 63 of the first detection valve 62, eliminating the need for a separate valve member for the second detection valve 80. This reduces the number of components. Furthermore, the first detection valve 62 and the second detection valve 80 share the outlet chamber 74 and the discharge path 76. Therefore, compared to having separate outlet chambers 74 and discharge paths 76, space can be saved inside the housing 1. Consequently, corresponding to the fewer components, or through space saving, the overall size of the clamping device can be reduced to a smaller size. As a result, a clamping device with two detection valves capable of detecting operational states can be manufactured with a simple structure.

[0060] Figures 4 to 6 A second embodiment of the present invention is shown. In this second embodiment, components that are the same as (or similar to) the structural components of the first embodiment described above are generally labeled with the same reference numerals and described.

[0061] In the first embodiment described above, the clamping device is inserted into the mounting hole of the worktable T and fixed by bolts. In contrast, in the clamping device of the second embodiment, the housing 1 is mounted on the movable part R of the robot arm.

[0062] Furthermore, the clamping device in the first embodiment includes a cover member 33, while the clamping device in the second embodiment does not include a cover member 33. Therefore, the two engaging members 39 are arranged symmetrically about the axis of the clamping rod 20 on the outer periphery of the clamping rod 20. A mounting groove 43 is formed in the horizontal direction on the outer periphery of the engaging member 39, and an annular elastic member 50 is mounted in the mounting groove 43. The radially inward force generated by the elastic member 50 presses the engaging member 39 toward the axis of the clamping rod 20. The engaging member 39 can be inserted into the receiving hole 32 of the upper housing 4 in a vertical and radial (horizontal) direction. A flange portion 90 protrudes from the lower part (base) of the engaging member 39 toward the radially outward direction of the clamping rod 20. The flange portion 90 faces the top surface of the receiving hole 32 in a manner that allows it to abut from above.

[0063] Furthermore, the clamping device of the first embodiment includes a support mechanism 53 consisting of a push spring 52 and a spring receiving member 51. In contrast, the support mechanism 53 of the clamping device of the second embodiment is configured as follows.

[0064] An annular first support member 91 is movable in the vertical direction and inserted into the receiving hole 32, supporting the engaging member 39 from below. Furthermore, a fifth hole 15 is formed with a larger diameter than the fourth hole 14, continuous with the upper side of the fourth hole 14 of the cylinder bore 10. A cylindrical second support member 92 is inserted in a sealed manner between the inner circumferential surface of the fifth hole 15 and the outer circumferential surface of the piston rod 17, movable in the vertical direction. The upper surface of the second support member 92 abuts against the lower surface of the first support member 91. A working chamber 93 is formed by dividing the cylinder bore 10 into the fifth hole 15, the second support member 92, and the piston rod 17. A communication path 94 connecting the working chamber 93 to the locking chamber 26 is formed within the housing 1. Therefore, when pressurized oil from a pressure oil source is supplied to the locking chamber 26 via the supply discharge path 28, the pressurized oil is also supplied to the working chamber 93 via the supply discharge path 28 and the communication path 94. As a result, the pressure of the oil in the working chamber 93 causes the second support member 92 to rise, which presses the first support member 91 toward the top of the receiving hole 32.

[0065] Furthermore, the lower surface of the first support member 91 can abut against the upper surface of the piston rod 17. Therefore, when the piston 16 and piston rod 17 are raised by the pressure of the pressurized oil supplied to the release chamber 27, the piston rod 17 presses against the top surface of the receiving hole 32 towards the first support member 91. In this embodiment, the support mechanism 53 is configured as described above, but it is not limited to this, and the support mechanism of the first embodiment described above may also be used.

[0066] Furthermore, in the first embodiment, the first detection valve 62 for overtravel detection has a first valve surface 72 on the upper surface of the valve member 63. In contrast, in the second embodiment, the first detection valve 62 for overtravel detection has a sealing member 95 fitted into an annular mounting groove on the upper surface of the valve member 63, and the sealing member 95 has the first valve surface 72 on its upper surface. Furthermore, in the clamping device of this embodiment, a sealing member 95 is fitted into the valve member, but this is not a limitation; the sealing member may also be fitted into a mounting groove provided in the stepped portion 70.

[0067] Furthermore, in the first embodiment, the second detection valve 80 for release detection has a second valve seat 84 provided on the lower surface of the sealing member 81 fitted into the inner peripheral wall of the third hole 13. In contrast, in the second embodiment, the second detection valve 80 for release detection has a second valve seat 84 on the lower surface of the step portion 82 formed between the third hole 13 and the fourth hole 14. Therefore, near the upper limit position when the piston 16 moves from the lower position toward the upper limit position, firstly, the piston 16 presses upward against the sealing member 95 of the valve member 63 and engages with the step portion 70, slightly flattening the sealing member 95. Then, by receiving the operating part 69 onto the step portion 82, the piston 16 is stopped. Thus, in the released state of the clamping device when the piston 16 has moved to the upper limit position, the first detection valve 62 reliably closes, and the second detection valve 80 also reliably closes.

[0068] In the clamping device of the second embodiment, the cover member 96, which seals the lower end opening of the cylinder bore 10, is assembled in a sealed manner. Therefore, the release chamber 27 is formed by dividing the space using the piston 16, the cover member 96, and the cylinder bore 10. In the clamping device of the second embodiment, the cover member 96 may also be omitted, and the release chamber 27 may be formed by dividing the space using the cylinder bore 10, the piston 16, the bottom wall of the mounting hole of the worktable T, and the base member of the robot R, as in the clamping device of the first embodiment.

[0069] Figure 7 A third embodiment of the present invention is shown. In this third embodiment, components that are the same as (or similar to) the structural components of the first and second embodiments described above are generally labeled with the same reference numerals and described.

[0070] In the clamping devices of the first and second embodiments described above, the piston rod 17 and the clamping rod 20 are composed of different components, and the clamping rod 20 is movably connected to the piston rod 17 in a horizontal direction. In contrast, in the clamping device of the third embodiment, the piston rod 17 and the clamping rod 20 are integrally formed, and the output member 23 is constituted by the piston rod 17 and the clamping rod 20.

[0071] Furthermore, in the clamping device of the first embodiment described above, the engaging member 39 can move within the support hole 36 of the cover member 33. In the clamping device of the second embodiment, the engaging member 39 can move horizontally on the first support member 91. In contrast, in the clamping device of the third embodiment, the base end of the engaging member 39 is configured to be unable to move horizontally on the spring receiving member 51. Additionally, the front end 39a of the engaging member 39 is thinner than the base end. Therefore, by moving the clamping rod 20 downwards, the wedge surface 41 of the clamping rod 20 presses the front end 39a of the engaging member 39 radially outwards, causing the front end 39a to elastically deform radially outwards relative to the base end.

[0072] The above-described embodiments and variations can be further modified in the following ways.

[0073] Instead of fixing the clamping device of the above embodiment to the worktable or the movable part of the robot, it can also be installed in other locations, such as the movable part of a turntable or a tray. Furthermore, instead of the workpiece or tool to be clamped, a workpiece tray, a mold, or the like can also be used.

[0074] Instead of having two engaging members 39 arranged circumferentially, one or more can be arranged. Furthermore, instead of forming the engaging member 39 into a generally rectangular shape, an annular sleeve with spheres and slits can be used to construct the engaging member 39.

[0075] In the clamping device of the above embodiment, a hydraulic cylinder is provided that is driven by pressurized oil supplied to the locking chamber 26 and the release chamber 27. Alternatively, a hydraulic cylinder driven by other liquids, such as a water cylinder, can be used, or a pneumatic cylinder driven by gases such as compressed air or compressed nitrogen can be used. For hydraulic (fluid pressure) cylinders, instead of the exemplified double-acting type, cases where locking is driven by pressurized fluid and releasing is driven by spring force, and cases where locking is driven by spring force and releasing is driven by pressurized fluid, can be considered.

[0076] Instead of arranging the clamping device vertically, it can also be arranged vertically in opposite directions, horizontally, or diagonally.

[0077] Instead of the case where the upper surface of the piston 16 can abut against the lower surface of the valve member 63, a protrusion or the like that protrudes radially outward from the outer peripheral wall of the piston rod 17 (and forms part of the piston rod 17) can also abut against the lower surface of the valve member 63.

[0078] In addition, various changes can of course be made within the scope that can be conceived by those skilled in the art.

[0079] Figures 8 to 11 A fourth embodiment of the present invention is shown. In this fourth embodiment, components that are the same as (or similar to) the structural components of the first embodiment described above are generally labeled with the same reference numerals and described.

[0080] In the first embodiment, a mounting groove is formed circumferentially on the inner peripheral wall of the third hole 13 of the cylinder bore 10, and an annular sealing member 81 is mounted in the mounting groove. The sealing member 81 is received from above by the stepped portion (top surface of the third hole) 82 and flattened by the piston 16 which has moved to near the upper limit position. Afterward, the piston 16 is received by the stepped portion 70 via the valve member 63. Therefore, in the released state of the clamping device when the piston 16 has moved to the upper limit position, the second detection valve 80 is reliably closed, and the first detection valve 62 is reliably closed.

[0081] In the first embodiment, the piston 16 and piston rod 17 are externally inserted into the lower side of the piston rod 17 in a manner that prevents relative changes in their vertical positions. A retaining ring 98 is mounted on the lower side of the piston 16. The piston 16 is clamped between the retaining ring 98 and the diameter variation portion S of the piston rod 17 and its position is fixed (see reference). Figure 1 The upward movement is stopped by bringing the piston 16 abutting against the sealing member 81, but at this time the second detection valve 80 must be reliably closed. Thus, by using the sealing member 81 of the first embodiment, slight flattening is allowed, thereby allowing the position of the piston 16 and the piston rod 17 to shift.

[0082] In the fourth embodiment, the relative positions of the piston 16 and the piston rod 17 in the axial direction are allowed to change. In the fourth embodiment, there is no diameter variation section S that limits the upper limit position of the piston 16 inserted into the piston rod 17. A major change in the fourth embodiment is that the piston 16 is not fixed to the piston rod 17 but can slide. Specifically, the diameter of the piston rod 17 with the inserted piston 16 is made uniform within a specified range so that the piston 16 can slide axially. In this embodiment, for the sake of simplifying piston rod manufacturing, it is made uniform to the position of the operating part 69. On the other hand, the lower limit position of the piston 16 is defined by the retaining ring 98. As a result, if the valve member 63 is not present, the piston 16 can move to the position of the operating part 69.

[0083] Other major changes compared to the first embodiment are as follows: First, a trapping valve 97 is added to the discharge path 76. Furthermore, a pipe member is provided within the cylinder bore 10 penetrating the housing 1, and the inner wall of this pipe member serves as a first hole 11 for the piston 16 to slide through.

[0084] The trap valve 97 is a valve that opens and closes by the left-right movement of the ball 97a. The trap valve 97 prevents external debris (foreign objects), coolant, and moisture from flowing into the housing. The spring 97b of the trap valve 97 has a low spring constant, causing it to contract even with a weak force from the inside. When the ball 97a moves to the left, the trap valve 97 opens.

[0085] exist Figure 8 In the clamping device in the released state shown, the piston 16 is supported on the stepped portion 70 of the housing 1 via the valve member 63. As a result, the first valve face 72 of the valve member 63 engages with the first valve seat 71, and the first detection valve 62 for overtravel detection closes.

[0086] In the released state, the piston rod 17 moves to the upper limit position. Therefore, the second valve face 85 of the operating part 69 of the piston rod 17 engages with the second valve seat 84, and the second detection valve 80 for release detection closes.

[0087] Figure 11 This is a partially enlarged view illustrating the relationship between piston 16 and piston rod 17. Piston 16 and piston rod 17 rise independently by supplying pressurized oil to release chamber 27. Figure 11 In step A, the piston 16 is slightly offset upward relative to the piston rod 17, creating a gap g between it and the retaining ring 98. That is, the second detection valve 80 and the first detection valve 62 are closed independently, resulting in the gap g. The gap g is the positional deviation between the piston 16 and the piston rod 17. The existence of the gap g is tolerated by allowing the piston 16 to slide relative to the piston rod 17 within a specified range, thus eliminating the need for critical assembly precision. Furthermore, since the sealing member 81 of the first embodiment is unnecessary, the number of components can be reduced, and the manufacturing time can be decreased.

[0088] exist Figure 9 The image shows the locked state. Pressure oil is discharged from release chamber 27, and pressure oil is supplied to locking chamber 26. Piston rod 17 and clamping rod 20 descend toward the locked position. At this time, the second valve face 85 of piston rod 17, formed on operating section 69, separates from the second valve seat 84, and second detection valve 80 opens. By opening the second detection valve 80, trapping valve 97 opens, allowing compressed air in second valve chamber 83 to be discharged through discharge path 76.

[0089] On the other hand, the operating part 69 of the piston rod 17 is separated from the valve member 63 by a predetermined distance upward, and the operating part 69 does not operate the valve member 63. Therefore, the state in which the valve member 63 is raised to the upper limit position by the pressure of the pressure oil supplied to the locking chamber 26 is maintained. As a result, the first valve face 72 engages with the first valve seat 71, and the closure of the first detection valve 62 is maintained.

[0090] exist Figure 11 In step B, by lowering piston 16, it comes into contact with the retaining ring, and the gap g disappears. Then, piston 16 and piston rod 17 descend together. Thus, when switching from the released state to the locked state, piston 16 and piston rod 17 are constrained by retaining ring 98.

[0091] Figure 10 The overtravel state of the clamping device is shown. Similar to the first embodiment, the operating part 69 of the piston rod 17 engages with the valve member 63, causing the valve member 63 to descend. The first detection valve 62 opens. Compressed air in the first inlet chamber 73 of the first valve chamber 68 merges with compressed air generated by the opening of the second detection valve 80 and is discharged through the discharge path 76.

[0092] Figure 12 The fifth embodiment of the present invention is shown. The fifth embodiment is related to... Figure 4 The third embodiment is largely the same, but some parts have been modified. In principle, the same reference numerals are used to label and describe components that are the same as or similar to structural components.

[0093] exist Figure 4 In the clamping device, the piston 16 is inserted externally into the lower side of the piston rod 17 in a manner that prevents the relative position of the piston 16 and the piston rod 17 from changing in the vertical direction. A retaining ring 98 is installed on the lower side of the piston 16. The piston 16 is clamped between the retaining ring 98 and the diameter variation part S of the piston rod 17 and its position is fixed.

[0094] By bringing the second valve seat 84 abutting against the second valve face, the upward movement of the piston rod 17 is stopped. However, at this time, the valve member 63, which is pushed upward by the piston 16, must be used to reliably close the first detection valve 62. Therefore, in Figure 4 In the clamping device, a sealing member 95 of the valve member 63 is provided between the stepped portion 70 of the housing and the valve member 63. By using the sealing member 95 of the fourth embodiment, slight flattening is allowed, thereby allowing the positional displacement of the piston 16 and the piston rod 17.

[0095] On the other hand, Figure 12 In the clamping device, the sealing member 95 of the valve member 63 is omitted, and the first detection valve 62 is formed only by the first valve seat 71 and the first valve face 72. Furthermore, an elastic member 100 is provided between the piston 16 and the valve member 63. When the piston 16 moves to near its upper limit position, the second detection valve 80 closes. Afterward, the piston 16 abuts against the elastic member 100 and is slightly flattened. Next, the piston 16 abuts against the first valve seat 71 of the stepped portion 70 via the sealing member 95 and the valve member 63, and the first detection valve 62 closes.

[0096] Alternatively, a component made of the same material as the sealing component 95 can be used as the elastic element 100. Alternatively, a spring can be used as the elastic element 100.

[0097] Explanation of reference numerals in the attached figures

[0098] 1. Shell

[0099] 10-cylinder bore

[0100] 16-piston

[0101] 23 Output Components

[0102] 39-clamping components

[0103] 41 wedge

[0104] 45 Clamping object

[0105] 46 holes

[0106] 61 first flow path

[0107] 62 First detection valve

[0108] 63 Valve Components

[0109] 69 Operations Department

[0110] 71 First Valve Seat

[0111] 72 First valve face

[0112] 79 Second Flow Path

[0113] 80 Second detection valve

[0114] 84 Second Valve Seat

[0115] 85 Second valve face.

Claims

1. A clamping device, characterized in that, The clamping device includes: A piston (16) is axially movable and inserted into a cylinder bore (10) formed within a housing (1); Output member (23) is provided to protrude from the piston (16) toward the front end side in the axial direction; Engaging member (39) engages with a wedge (41) formed in the output member (23) and moves in a direction intersecting the axial direction by the movement of the output member (23) toward the axial direction. The engaging member (39) is externally fitted into a hole (46) of the clamping object (45) and can engage with the inner circumferential surface of the hole (46). A first flow path (61) for detecting pressure fluid is formed within the housing (1); The first detection valve (62) is located in the middle of the first flow path (61). By moving the piston (16) or the output member (23) to a predetermined position on the base end side of the axial direction, the first flow path (61) is cut off or opened. A second flow path (79) for detecting pressure fluid is formed within the housing (1); as well as The second detection valve (80) is located in the middle of the second flow path (79). By moving the piston (16) or the output member (23) to a predetermined position on the axial front end side, the second flow path (79) is cut off or opened. The first detection valve (62) is composed of a valve component (63), an operating part (69), a first valve seat (71), and a first valve face (72). The valve member (63) is cylindrical and is inserted in a sealed manner between the outer peripheral surface of the output member (23) and the inner peripheral surface of the cylinder bore (10) in a manner that allows it to move along the axial direction. The valve member (63) faces the piston (16) or the output member (23) at a predetermined interval in the axial direction in a manner that allows it to abut against the piston (16) or the output member (23). The operating part (69) protrudes from the outer peripheral wall of the output member (23) in a direction intersecting the axial direction, and faces the valve member (63) at a predetermined interval in the axial direction in a manner that allows it to engage with the valve member (63); The first valve seat (71) is formed within the cylinder bore (10). The first valve face (72) is formed on the valve member (63) and can engage with the first valve seat (71). The second detection valve (80) is composed of a second valve seat (84) and a second valve face (85). The second valve seat (84) is formed within the cylinder bore (10). The second valve face (85) is formed on the operating part (69) and can engage with the second valve seat (84).

2. The clamping device according to claim 1, characterized in that, The piston (16) is externally inserted into the piston rod (17) of the output member (23), and the piston (16) is capable of sliding axially within a predetermined range relative to the piston rod (17). The first detection valve (62) is closed by the action of the piston (16), and the second detection valve (80) is closed by the action of the piston rod (17).

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