TWI742407B - Holding device - Google Patents

Abstract

The holding device includes a cylindrical body, a piston, a top cover, a pair of jaw seats, an LVDT sensor, and a force applying member. The LVDT sensor has a cylindrical sensor box, a primary coil and two secondary coils wound around the sensor box, and a piston that reciprocates integrally and can appear and disappear relative to the sensor box. Mandrel. The force applying member abuts against the sensor box around the axis of the sensor box and applies force to the sensor box toward the top cover, thereby cooperating with the top cover to clamp the sensor box.

Description

Holding device

The invention relates to a holding device.

For example, Japanese Patent Application Laid-Open No. 11-320474 discloses a conventional holding device 100 as shown in FIG. 7. The holding device 100 includes a cylindrical body 102, a piston 103, and a pair of master jaws 104. The body 102 has a cylinder chamber 101 into which fluid is supplied and discharged. The piston 103 is housed in the cylinder chamber 101 and reciprocates by the fluid supplied and discharged from the cylinder chamber 101. The pawl holder 104 performs opening and closing operations in accordance with the reciprocating movement of the piston 103.

In addition, the above-mentioned holding device 100 uses an LVDT sensor 105 (differential transformer) in order to detect the position of the pair of jaw holders 104. The LVDT sensor 105 has: a cylindrical sensor housing 106; a primary coil 107 and two secondary coils 108 wound around the sensor housing 106; and a mandrel 109 that reciprocates integrally with the piston 103 It moves and can appear and disappear relative to the sensor box 106. AC voltage is applied to the primary coil 107. In addition, the mandrel 109 reciprocates in accordance with the reciprocating movement of the piston 103, thereby generating a pressure difference between the induced voltages generated by the two secondary coils 108. The difference in the induced voltage varies according to the position of the core shaft 109. In addition, there is a proportional relationship between the movement amount of the pair of jaw seats 104 and the movement amount of the piston 103. Therefore, the amount of movement of the mandrel 109, that is, the amount of movement of the piston 103 can be detected by the amount of change in the difference of the induced voltage, and as a result, the amount of movement of the pair of jaw holders 104 can be detected. Thereby, it is possible to linearly detect the position of the pair of pawl holders 104, and to detect the position of the pair of pawl holders 104 with high accuracy.

In the holding device 100, a first top cover 111 and a second top cover 112 are attached to the end of the body 102 in the axial direction. The first top cover 111 is formed with a through hole 111 a through which the sensor box 106 penetrates. The sensor box 106 penetrates the through hole 111a of the first top cover 111, and a part of it is sandwiched by the first top cover 111 and the second top cover 112, thereby being fixed to the first top cover 111 and the second top cover 111.二顶盖112。 Two top cover 112. In addition, the first top cover 111 and the second top cover 112 are installed at the end of the main body 102 so that the sensor box 106 is located in the main body 102 in a state where it is coaxially arranged with the piston 103.

At this time, the sensor box 106 is located in the body 102 in a state of being cantilevered and supported by the first top cover 111 and the second top cover 112. Therefore, depending on the installation state of the first top cover 111 and the second top cover 112 on the main body 102, the sensor case 106 may be arranged in the main body 102 in a state inclined with respect to the axis of the mandrel 109. Therefore, it may be difficult for the mandrel 109 to come and go with respect to the sensor case 106, so that the position of the pair of jaw holders 104 cannot be detected with high accuracy.

The purpose of the present disclosure is to provide a holding device capable of smoothly performing the movement of the mandrel with respect to the sensor case.

The holding device that achieves the above-mentioned object is provided with: a cylindrical body with a cylinder chamber in which fluid is supplied and discharged; Reciprocating movement; a top cover, which is mounted on the end of the body in the axial direction; a pair of claw seats, which open and close with the reciprocating movement of the piston; and an LVDT sensor to be coaxial with the piston The configured state is built into the body, and the position of the pair of claw holders is detected. The LVDT sensor has: a cylindrical sensor case; a primary coil and two secondary coils wound around the sensor case; and a mandrel that reciprocates integrally with the piston , And can appear and disappear relative to the sensor box. The holding device includes an urging member that abuts against the sensor case around the axis of the sensor case, and urges the sensor case toward the top cover, thereby interacting with The top cover cooperates to clamp the sensor box.

In the above-mentioned holding device, it is preferable that a ring-shaped sealing member is provided on the outer peripheral surface of the sensor box, and the sealing member interacts with the outer peripheral surface of the sensor box and the inner peripheral surface of the body. Sealing is performed between them to prevent fluid from leaking from the cylinder chamber.

In the above-mentioned holding device, it is preferable that the top cover has an external thread portion screwed into the body, and the holding device further includes a rotation preventing mechanism that prevents the sensor case from being relative to the body. The fuselage rotates.

Hereinafter, an embodiment of the actualized holding device will be described based on FIGS. 1 to 5.

As shown in FIG. 1, the holding device 10 includes a body 11 having a square tube shape. The body 11 is formed with a circular hole-shaped through hole 12 penetrating in the axial direction of the body 11. The through hole 12 is formed by the female screw hole 13, the sensor housing hole 14, the cylinder hole 15, the rod insertion hole 16, and the housing hole 17. The internally threaded hole 13, the sensor housing hole 14, the cylinder hole 15, the rod insertion hole 16, and the housing hole 17 are arranged in this order from the first end to the second end in the axial direction of the body 11 Formed in the body 11. As a result, the female screw hole 13 opens on the first end surface 11 a of the body 11. The receiving hole 17 is opened on the second end surface 11 b of the body 11.

The end portion of the internally threaded hole 13 on the side opposite to the first end surface 11 a of the body 11 communicates with the sensor housing hole 14. The end of the sensor accommodating hole 14 on the side opposite to the female screw hole 13 communicates with the cylinder hole 15. The end of the cylinder hole 15 on the side opposite to the sensor housing hole 14 communicates with the rod insertion hole 16. The end of the rod insertion hole 16 on the side opposite to the cylinder hole 15 communicates with the housing hole 17.

The hole diameter of the internally threaded hole 13 is larger than the hole diameter of the sensor receiving hole 14. In addition, the hole diameter of the sensor housing hole 14 is larger than the hole diameter of the cylinder hole 15. Thus, the body 11 has an annular first step surface 18 that connects the inner circumferential surface of the sensor housing hole 14 with the inner circumferential surface of the cylinder hole 15 and is connected to the body 11 The axis direction extends in a direction orthogonal to the axis. In addition, the hole diameter of the cylinder hole 15 is larger than the hole diameter of the rod insertion hole 16. Thus, the body 11 has an annular second step surface 19 that connects the inner circumferential surface of the cylinder hole 15 with the inner circumferential surface of the rod insertion hole 16 and is connected to the inner circumferential surface of the body 11 It extends in a direction orthogonal to the axial direction.

The diameter of the rod insertion hole 16 is smaller than the diameter of the housing hole 17. Thus, the body 11 has an annular third stepped surface 20 that connects the inner circumferential surface of the rod insertion hole 16 with the inner circumferential surface of the receiving hole 17 and is aligned with the axis of the body 11 Extend in the direction orthogonal to the direction. An annular seal fitting groove 16 a is formed on the inner peripheral surface of the rod insertion hole 16. The seal assembly groove 16 a opens on the third step surface 20.

As shown in FIG. 2, the sensor housing hole 14 is formed of a small-diameter hole 14a and a large-diameter hole 14b having a larger diameter than the small-diameter hole 14a. The small-diameter hole 14a is located closer to the cylinder hole 15 than the large-diameter hole 14b and communicates with the cylinder hole 15. The large-diameter hole 14b communicates with the internally threaded hole 13. The inner circumferential surface of the small-diameter hole 14a and the inner circumferential surface of the large-diameter hole 14b are connected by a conical tapered surface 14c. The diameter of the tapered surface 14c decreases from the large-diameter hole 14b toward the small-diameter hole 14a.

As shown in FIG. 1, a pair of flat support portions 21 protrude from the second end surface 11 b of the body 11. In FIG. 1, for ease of drawing, only one of the two supporting parts 21 is shown. The pair of support portions 21 protrude from the second end surface 11 b of the fuselage 11 in the axial direction of the fuselage 11. The two support portions 21 extend parallel to each other. The through hole 12 opens between the two support parts 21.

A disc-shaped spring seat member 22 is housed in the through hole 12. The outer diameter of the spring seat member 22 is larger than the diameter of the cylinder hole 15 and slightly smaller than the diameter of the small diameter hole 14 a of the sensor housing hole 14. The outer peripheral portion of the first end surface 22 a of the spring seat member 22 abuts on the first step surface 18. An annular spring receiving groove 22c is formed on the second end surface 22b of the spring seat member 22. A circular hole-shaped insertion hole 22h is formed in the center of the spring seat member 22.

In addition, the cylinder chamber 23 is defined by the first end surface 22 a of the spring seat member 22, the inner peripheral surface of the cylinder hole 15, and the second step surface 19 in the through hole 12. Thus, the body 11 has a cylinder chamber 23. An annular piston 24 is housed in the cylinder chamber 23. An annular piston seal 25 is attached to the outer peripheral surface of the piston 24. The piston seal 25 seals between the outer circumferential surface of the piston 24 and the inner circumferential surface of the cylinder bore 15.

The piston 24 partitions the cylinder chamber 23 into a first pressure application chamber 26 adjacent to the spring seat member 22 and a second pressure application chamber 27 adjacent to the second step surface 19. A first fluid supply and discharge port 28 communicating with the first pressure application chamber 26 is formed in the vicinity of the spring seat member 22 in the outer peripheral wall of the body 11. In addition, in the first pressure application chamber 26, the fluid is selectively supplied and discharged through the first fluid supply and discharge port 28. In addition, in the vicinity of the second step surface 19 in the outer peripheral wall of the fuselage 11, a second fluid supply and discharge port 29 communicating with the second pressure application chamber 27 is formed. In addition, in the second pressure application chamber 27, the fluid is selectively supplied and discharged through the second fluid supply and discharge port 29. Therefore, the fluid is supplied to and discharged from the cylinder chamber 23. The first pressure application chamber 26 and the second pressure application chamber 27 are supplied with and discharged fluid, so that the piston 24 reciprocates in the cylinder chamber 23. Therefore, the piston 24 reciprocates in the cylinder chamber 23 by being supplied and discharged from the fluid in the cylinder chamber 23.

The piston 24 is integrated with a piston rod 30, and the piston rod 30 extends from the end face of the piston 24 on the opposite side to the spring seat member 22 in the axial direction of the body 11. As a result, the piston rod 30 and the piston 24 move integrally. The piston rod 30 passes through the rod insertion hole 16 and the receiving hole 17 to protrude from the second end surface 11 b of the body 11. The top end portion of the piston rod 30 on the side opposite to the piston 24 is located between the two support portions 21. Thereby, the piston rod 30 is configured to be able to come and go with respect to the body 11 between the two support parts 21.

A rod seal 31 is installed in the seal assembly groove 16a. The rod seal 31 seals between the inner peripheral surface of the rod insertion hole 16 and the outer peripheral surface of the piston rod 30. In addition, a detachment prevention member 32 is arranged in the storage hole 17. The detachment preventing member 32 prevents the rod seal 31 from escaping from the seal fitting groove 16a.

The holding device 10 includes a pair of claw seats 33 that perform opening and closing operations in accordance with the reciprocating movement of the piston 24. In addition, the holding device 10 is provided with a guide plate 34 that guides the two claw seats 33 in a direction to approach or separate from each other. The guide plate 34 is attached to an end portion of the pair of support portions 21 on the side opposite to the second end surface 11 b of the body 11. An end surface of the guide plate 34 on the side opposite to the pair of support portions 21 is formed with a guide recess 34a that guides the two claw seats 33 in a direction toward or apart from each other. In addition, the guide plate 34 is formed with a pair of through holes 34h for operating handles.

The holding device 10 includes a pair of operating handles 35. Each operation handle 35 has a substantially L-shaped plate shape. A part of each operating lever 35 is arranged between the two supporting parts 21. A U-shaped engagement groove 35a is formed at the first end of each operating handle 35. The engaging groove 35 a of each operating lever 35 engages with an engaging shaft 36 provided at the tip portion of the piston rod 30. In addition, a support shaft 37 penetrates through the L-shaped curved portion of each operating lever 35, respectively. Each support shaft 37 is fixed to the pair of support portions 21 in a state of being bridged by the pair of support portions 21. In addition, the piston rod 30 rotates with the support shaft 37 corresponding to each operating handle 35 as the center of rotation by moving in and out of the body 11.

The second end of each operation lever 35 passes through the corresponding operation lever through-hole 34 h and protrudes from the end surface of the guide plate 34 on the opposite side to the pair of support portions 21. An engaging piece 38 is provided at the other end of each operating handle 35. In addition, the engaging member 38 of each operating lever 35 is inserted into the receiving recess 33 h formed in the corresponding claw seat 33. Thereby, each engaging member 38 and the corresponding storage recess 33h are hooked to each other. By the hooks of each engaging member 38 and the corresponding storage recess 33h, the claw seat 33 corresponding to the tip portion of each operating handle 35 is connected.

As shown in FIG. 3, when fluid is supplied from the second fluid supply and discharge port 29 to the second pressure application chamber 27, the piston 24 starts to move to the spring seat member 22. As a result, the fluid in the first pressure application chamber 26 is discharged to the outside through the first fluid supply and discharge port 28, and the piston 24 moves toward the spring seat member 22. As a result, the piston rod 30 moves in the sinking direction with respect to the body 11. Along with the movement of the piston rod 30 in the sinking direction relative to the body 11, the first ends of the pair of operating handles 35 are pulled in by the piston rod 30 via the engaging shaft 36, and the engaging piece 38 corresponds to each operating handle 35 The support shaft 37 rotates in a direction in which the rotation center approaches each other. As the engaging member 38 moves in a direction approaching each other, the two jaw holders 33 move in a direction approaching each other, and the workpiece W1 is held.

As shown in FIG. 1, when the fluid is supplied from the first fluid supply and discharge port 28 to the first pressure application chamber 26, the piston 24 starts to move to the second step surface 19. As a result, the fluid in the second pressure application chamber 27 is discharged to the outside through the second fluid supply and discharge port 29, and the piston 24 moves to the second step surface 19. As a result, the piston rod 30 moves in the protruding direction with respect to the body 11. As the piston rod 30 moves in the protruding direction with respect to the body 11, the first ends of the pair of operating handles 35 are pushed by the piston rod 30 via the engaging shaft 36, and the engaging member 38 is provided with a support shaft corresponding to each operating handle 35 37 is the rotation center of rotation in the direction apart from each other. As the engaging member 38 moves in a direction apart from each other, the two jaw holders 33 move in a direction apart from each other, and the holding state of the workpiece W1 is released.

As shown in FIG. 2, a disk-shaped top cover 39 is attached to the internal threaded hole 13. Thereby, the top cover 39 is attached to the first end in the axial direction of the body 11. On the outer peripheral surface of the top cover 39, a male screw part 39a screwed into the female screw hole 13 is formed. Thereby, the top cover 39 has an external screw portion 39a screwed into the body 11. In the through hole 12, the sensor storage chamber 40 is divided by the top cover 39, the inner peripheral surface of the sensor storage hole 14, and the second end surface 22 b of the spring seat member 22. Thus, the body 11 has a sensor storage chamber 40.

The holding device 10 includes an LVDT sensor 50 that detects the position of the pair of pawl holders 33. The LVDT sensor 50 has: a cylindrical sensor case 51; a primary coil 61 and two secondary coils 62 wound around the sensor case 51; and a mandrel 63, which is integrated with the piston 24 It reciprocates and can appear and disappear relative to the sensor box 51.

The sensor case 51 has a cylindrical main body 52 having a bottom made of resin. The main body 52 has a disc-shaped bottom wall 52a and a cylindrical peripheral wall 52b extending from the outer periphery of the bottom wall 52a. The inner diameter of the peripheral wall 52b is the same as the diameter of the insertion hole 22h of the spring seat member 22. In addition, the main body portion 52 has an annular flange 52c that protrudes outward from an end of the peripheral wall 52b on the opposite side to the bottom wall 52a. In the sensor case 51, the primary coil 61 and the two secondary coils 62 are provided on the main body 52 by resin molding. The primary coil 61 and the two secondary coils 62 are embedded in the peripheral wall 52 b of the main body 52. The primary coil 61 and the two secondary coils 62 are arranged side by side in the axial direction of the main body 52. In the axial direction of the main body 52, the primary coil 61 is arranged between the two secondary coils 62.

In addition, the sensor case 51 has a cylindrical covering member 53 covering the outer peripheral surface of the peripheral wall 52 b of the main body portion 52. The covering member 53 is made of iron, for example. In addition, the sensor box 51 has a cylindrical case member 54 covering the outer peripheral surface of the covering member 53. The case member 54 is made of aluminum, for example. The outer diameter of the housing member 54 is substantially the same as the outer diameter of the flange 52c. The end surface of the housing member 54 opposite to the flange 52c is in contact with the flange 52c. In addition, the end surface of the housing member 54 opposite to the top cover 39 abuts against the top cover 39.

The outer diameter of the flange 52 c and the outer diameter of the housing member 54 are slightly smaller than the diameter of the small diameter hole 14 a of the sensor housing hole 14. The sensor box 51 is stored in the sensor storage room 40. The flange 52c is arranged inside the small diameter hole 14a. The axial center of the peripheral wall 52 b of the main body portion 52 coincides with the axial center of the insertion hole 22 h of the spring seat member 22.

The mandrel 63 has an external thread 63a. The piston 24 has an internally threaded hole 24h on an end surface opposite to the spring seat member 22. The external thread 63a of the mandrel 63 is threadedly engaged with the internal thread hole 24h of the piston 24. In addition, the male screw 63a is screwed into the female screw hole 24h, and the core shaft 63 is integrated with the piston 24 in a state extending from the end face of the piston 24 opposite to the spring seat member 22 in the axial direction of the body 11. In addition, a nut 64 is screwed to the external thread 63a, and loosening of the external thread 63a with respect to the internal threaded hole 24h is suppressed.

The core shaft 63 is inserted from the cylinder chamber 23 through the insertion hole 22 h of the spring seat member 22 to the inner side of the peripheral wall 52 b of the main body portion 52. The outer diameter of the core shaft 63 is smaller than the inner diameter of the peripheral wall 52b and the diameter of the insertion hole 22h of the spring seat member 22. The LVDT sensor 50 is built in the body 11 in a state where it is arranged coaxially with the piston 24.

An AC voltage is applied to the primary coil 61. The mandrel 63 reciprocates inside each secondary coil 62 in accordance with the reciprocating movement of the piston 24 to generate an induced voltage in each secondary coil 62.

The urging member 65 is accommodated in the spring accommodating groove 22c of the spring seat member 22. The urging member 65 is, for example, a wave washer. The urging member 65 abuts on the end surface of the main body 52 on the side opposite to the bottom wall 52a. Thereby, the urging member 65 abuts against the sensor case 51 around the axis of the sensor case 51 and urges the sensor case 51 toward the top cover 39. In addition, the urging member 65 cooperates with the top cover 39 to sandwich the sensor case 51.

An annular sealing member 66 is attached to the outer peripheral surface of the flange 52c. The sealing member 66 seals between the outer peripheral surface of the flange 52c and the inner peripheral surface of the small diameter hole 14a. As a result, a sealing member 66 is provided on the outer peripheral surface of the sensor box 51. The sealing member 66 seals the outer peripheral surface of the sensor box 51 and the inner peripheral surface of the body 11 to prevent fluid from flowing from the cylinder chamber. 23 Leakage.

The holding device 10 further includes a rotation preventing mechanism 70 that prevents the sensor case 51 from rotating relative to the body 11. The rotation preventing mechanism 70 is composed of a bolt 71 screwed into the outer peripheral surface of the housing member 54 and a hole 72 formed in the body 11, and the head 71 a of the bolt 71 is arranged inside the hole 72.

As shown in FIG. 4, a recess 11c is formed on the outer surface of the outer peripheral wall of the body 11. In addition, the hole 72 is formed in the bottom surface 11d of the recess 11c. The hole 72 communicates with the large-diameter hole 14 b of the sensor housing hole 14. In a plan view, the hole 72 has an elliptical hole shape. The longitudinal direction of the hole 72 coincides with the axial direction of the fuselage 11. The inner peripheral edge of the hole 72 is formed by a pair of long side edges 72a, a first curved edge 72b, and a second curved edge 72c. The two long side edges 72 a extend parallel to each other in the length direction of the hole 72. The first curved edge 72b is curved in an arc shape, and connects the first ends of the two long side edges 72a to each other. The second curved edge 72c is curved in an arc shape, and connects the second ends of the two long side edges 72a to each other.

As shown in FIG. 2, the flange 52c is arranged inside the small diameter hole 14a, and the head 71a of the bolt 71 is located in the hole 72 in the state where the sensor case 51 is clamped by the urging member 65 and the top cover 39 Near the first curved edge 72b. At this time, in the axial direction of the body 11, the distance L1 between the head 71a of the bolt 71 and the second curved edge 72c of the hole 72 is greater than the distance L2 from the tapered surface 14c to the sealing member 66.

As shown in FIG. 4, the insertion hole 11h for wiring is formed in the bottom surface 11d of the recessed part 11c. As shown in FIG. 2, the wiring insertion hole 11 h is arranged closer to the top cover 39 than the hole 72, and communicates with the large-diameter hole 14 b of the sensor housing hole 14. In addition, a cutout 54k is formed in the case member 54. The wiring insertion hole 11h and the cutout 54k overlap in a direction orthogonal to the axial direction of the body 11. In addition, the electrical wiring 73 drawn from the primary coil 61 and the two secondary coils 62 extends toward the recess 11c through the cutout 54k and the wiring insertion hole 11h.

As shown in FIG. 1, an amplifier 74 is mounted on the outer surface of the outer peripheral wall of the body 11. As a result, the amplifier 74 and the holding device 10 are integrated. The amplifier 74 is mounted on the outer surface of the outer peripheral wall of the body 11 in a state of blocking the recess 11c. The end of the electrical wiring 73 on the opposite side to the primary coil 61 and the two secondary coils 62 is electrically connected to the amplifier 74. The amplifier 74 is electrically connected to the external control device 75 through the connector 74a. The amplifier 74 amplifies the induced voltage output from each secondary coil 62. In addition, the voltage amplified by the amplifier 74 is supplied to the external control device 75 via the connector 74a.

Next, the effect of this embodiment will be described.

The mandrel 63 reciprocates along with the reciprocating movement of the piston 24, thereby generating a pressure difference between the induced voltages generated by the two secondary coils 62. The difference in the induced voltage changes according to the position of the core shaft 63. In addition, there is a proportional relationship between the movement amount of the pair of claw seats 33 and the movement amount of the piston 24. Therefore, the external control device 75 detects the amount of change in the difference between the induced voltages supplied from the two secondary coils 62 via the electric wiring 73 and the amplifier 74, and can detect the amount of movement of the mandrel 63, that is, the amount of movement of the piston 24. As a result, the amount of movement of the pair of claw holders 33 can be detected. Thereby, the position of the pair of jaw holders 33 can be detected linearly, and the position of the pair of jaw holders 33 can be detected with high accuracy.

In addition, when the pair of jaw holders 33 are holding the workpiece W1, the external control device 75 detects the position of the pair of jaw holders 33, so that the size of the workpiece W1 can be measured based on the position information of the pair of jaw holders 33. . Therefore, the LVDT sensor 50 of this embodiment also functions as a length measuring sensor for measuring the size of the workpiece W1.

As shown in FIG. 5, for example, during maintenance, assembly and disassembly of the top cover 39 to the body 11 are performed. At this time, when the end surface of the housing member 54 opposite to the top cover 39 is in contact with the top cover 39, when the male screw portion 39a of the top cover 39 is screwed in or out of the female screw hole 13 , The sensor box 51 and the top cover 39 rotate together. At this time, the head 71 a of the bolt 71 is in contact with one of the two long side edges 72 a of the hole 72, thereby preventing the sensor box 51 from rotating relative to the body 11.

For example, at the time of maintenance, etc., when the sensor case 51 is removed from the main body 11, first, the top cover 39 is removed from the main body 11, and the amplifier 74 is removed from the outer surface of the outer peripheral wall of the main body 11. And, until the head 71a of the bolt 71 abuts on the second curved edge 72c of the hole 72, the head 71a of the bolt 71 moves toward the second curved edge 72c. Then, the sensor case 51 moves toward the female threaded hole 13, and the flange 52c is located inside the large-diameter hole 14b via the tapered surface 14c from the small-diameter hole 14a. Thereby, the sealing between the outer peripheral surface of the flange 52c and the inner peripheral surface of the small-diameter hole 14a by the sealing member 66 is released, and the sliding resistance between the sealing member 66 and the body 11 is reduced. As a result, the movement of the sensor box 51 in the axial direction within the body 11 is smoothly performed, and the sensor box 51 is easily detached from the body 11. In addition, by removing the bolt 71 from the housing member 54 and pulling out the sensor case 51 from the through hole 12, the sensor case 51 is detached from the main body 11.

In the above-mentioned embodiment, the following effects can be obtained.

(1) The holding device 10 includes an urging member 65 that abuts against the sensor case 51 around the axis of the sensor case 51 and urges the sensor case 51 toward the top cover 39, thereby It cooperates with the top cover 39 to clamp the sensor box 51. As a result, the sensor box 51 is clamped by the urging member 65 and the top cover 39 that abut on the axis of the sensor box 51. Therefore, it is possible to suppress the sensor box 51 from moving relative to the core shaft 63. It is arranged in the fuselage 11 in a state where the axis is inclined. Therefore, the mandrel 63 can be smoothly moved into and out of the sensor case 51.

(2) An annular sealing member 66 is provided on the outer peripheral surface of the sensor box 51, and the sealing member 66 seals between the outer peripheral surface of the sensor box 51 and the inner peripheral surface of the body 11, thereby The leakage of fluid from the cylinder chamber 23 is suppressed. Thereby, in the direction orthogonal to the axis of the sensor box 51, the elastic force of the ring-shaped sealing member 66 that suppresses the leakage of fluid from the cylinder chamber 23 can be used to affect the sensor box in the body 11 The position of the body 51 is positioned. Therefore, since the axis of the sensor case 51 can be restrained from shifting with respect to the axis of the core shaft 63, the movement of the core shaft 63 with respect to the sensor case 51 can be performed more smoothly.

(3) The top cover 39 has an external threaded portion 39a screwed into the body 11. In addition, the holding device 10 further includes a rotation preventing mechanism 70 that prevents the sensor case 51 from rotating relative to the body 11. Thereby, for example, when compared with the case where the top cover 39 is attached to the body 11 by press-fitting, the assemblability of the top cover 39 to the body 11 can be improved. In addition, for example, when the top cover 39 needs to be detached from the body 11 during maintenance, etc., the top cover can be easily detached from the body 11 when compared with the case where the top cover 39 is attached to the body 11 by press-fitting. 39. Moreover, when the top cover 39 is assembled and disassembled to the body 11, the rotation preventing mechanism 70 can prevent the sensor case 51 and the top cover 39 from rotating together. As a result, it is possible to avoid problems such as the electrical wiring 73 respectively connected to the primary coil 61 and the secondary coil 62 being stretched and damaged as the sensor housing 51 rotates.

(4) During maintenance, etc., when the sensor case 51 is removed from the body 11, until the head 71a of the bolt 71 abuts the second curved edge 72c of the hole 72, the head 71a of the bolt 71 is bent toward the second The edge 72c moves. Thereby, the sensor case 51 moves toward the female threaded hole 13, and the flange 52c can be positioned inside the large-diameter hole 14b from the small-diameter hole 14a via the tapered surface 14c. As a result, the seal between the outer peripheral surface of the flange 52c in the sealing member 66 and the inner peripheral surface of the small-diameter hole 14a is released, and the sliding resistance between the sealing member 66 and the body 11 can be reduced, and smooth performance can be achieved. The movement of the sensor box 51 in the axial direction in the body 11 allows the sensor box 51 to be easily detached from the body 11.

(5) According to this embodiment, since the mandrel 63 moves smoothly with respect to the sensor housing 51, the position of the pair of jaw holders 33 can be detected with high accuracy by the external control device 7.

In addition, the above-mentioned embodiment can be modified and implemented as follows. The above embodiments and the following modified examples can be combined with each other within the scope of technically not contradictory.

As shown in FIG. 6, the rotation preventing mechanism 70 may be composed of a bolt 81 screwed into the body 11 and a hole 82 formed in the sensor case 51 and having a shaft portion 81 a of the bolt 81 arranged inside. A female screw hole 11e into which the shaft portion 81a of the bolt 81 is screwed is formed in the bottom surface 11d of the recess 11c. The covering member 53 is formed with a groove 53 e through which the shaft portion 81 a of the bolt 81 is inserted. The hole 82, the groove 53e, and the female screw hole 11e overlap in a direction orthogonal to the axial direction of the body 11. In addition, the tip portion of the shaft portion 81a of the bolt 81 that has passed through the female screw hole 11e and the groove 53e is inserted into the hole 82. Thus, when the sensor box 51 wants to rotate together with the top cover 39, the inner peripheral surface of the hole 82 contacts the tip of the shaft portion 81a of the bolt 81, thereby preventing the sensor box 51 from relative to the body. 11 rotation. In addition, in the embodiment shown in FIG. 6, in order to reduce the size of the holding device 10, the outer diameter of the piston 24 is made smaller than that of the above-mentioned embodiment. Along with this, the outer diameter of the sensor case 51 also becomes smaller. Specifically, the sensor case 51 of the embodiment shown in FIG. 6 has a structure in which the housing member 54 explained in the above-mentioned embodiment is omitted.

In the embodiment, the ring-shaped sealing member 66 that prevents fluid from leaking from the cylinder chamber 23 may not be provided on the outer peripheral surface of the sensor case 51. For example, they may be provided on the outer peripheral surface of the spring seat member 22 and the spring, respectively. Between the second end surface 22b of the seat member 22 and the sensor box 51.

In the embodiment, the top cover 39 may also be installed to the body 11 by press-fitting.

In the embodiment, the urging member 65 may be, for example, a coil spring.

In the embodiment, the LVDT sensor 50 may not be a structure in which the primary coil 61 and the two secondary coils 62 are arranged side by side in the axial direction of the main body 52. For example, it may be in the two secondary coils 62. The structure in which the primary coil 61 is arranged on the circumferential side.

In the embodiment, the amplifier 74 may not be mounted on the outer surface of the outer peripheral wall of the body 11. The key point is that the amplifier 74 may not be integrated with the holding device 10.

In the embodiment, the body 11 is not limited to a square tube shape, and may be, for example, a cylindrical shape.

10: Holding device 11: body 23: Cylinder chamber 24: Piston 33: Master jaw 39: head cover 39a: External thread 50: LVDT sensor 51: Sensor box 61: Primary coil 62: Secondary coil 63: Mandrel 65: force component 66: Sealing member 70: Rotation prevention mechanism

Fig. 1 is a cross-sectional view of a holding device in an embodiment. Fig. 2 is an enlarged cross-sectional view showing the holding device. Fig. 3 is a cross-sectional view of the holding device showing a state in which the workpiece is held. Figure 4 is a top view of the fuselage. Fig. 5 is an exploded cross-sectional view of the holding device. Fig. 6 is an enlarged cross-sectional view showing a holding device in another embodiment. Fig. 7 is a cross-sectional view of a conventional holding device.

10: Holding device

11: body

11a: The first end face

11c: recess

11d: bottom surface

11h: Through hole for wiring

12: Through hole

13: Internal threaded hole

14: Sensor storage hole

14a: Small diameter hole

14b: Large diameter hole

14c: tapered surface

15: Cylinder hole

16: Seal assembly groove

18: The first step surface

19: The second step surface

22: Spring seat member

22a: first end face

22b: second end face

22c: Spring storage slot

22h: Through hole

23: Cylinder chamber

24: Piston

24h: internal threaded hole

25: Piston seal

26: The first pressure chamber

27: The second pressure chamber

28: First fluid supply and discharge port

29: Second fluid supply and discharge port

30: Piston rod

39: top cover

39a: External thread

40: Sensor storage room

50: LVDT sensor

51: Sensor box

52: main body

52a: bottom wall

52b: peripheral wall

52c: flange

53: Covering member 53

54: Shell member

54k: notch

61: Primary coil

62: Secondary coil

63: Mandrel

63a: external thread

64: Nut

65: force component

66: Sealing member

70: Rotation prevention mechanism

71: Bolt

71a: head

72: Hole

72a: Long side edge

72b: First bending edge

72c: second bending edge

73: electrical wiring

74: Amplifier

74a: Connector

L1: The distance between the head 71a of the bolt 71 and the second curved edge 72c of the hole 72

L2: The distance from the tapered surface 14c to the sealing member 66

Claims (3)

A holding device, characterized in that it has: A cylindrical body with a cylinder chamber where fluid is supplied and discharged; The piston is housed in the cylinder chamber and reciprocates by the fluid supplied and discharged from the cylinder chamber; The top cover is installed on the end of the fuselage in the axial direction; A pair of pawl seats, which open and close with the reciprocating movement of the piston; and The LVDT sensor is built into the body in a state coaxially arranged with the piston, and detects the position of the pair of jaw holders, The LVDT sensor has: Cylindrical sensor box; A primary coil and two secondary coils are wound around the sensor box; and The mandrel reciprocates integrally with the piston, and can appear and disappear relative to the sensor box, The holding device is provided with an urging member, the urging member abuts against the sensor case around the axis of the sensor case, and urges the sensor case toward the top cover, thereby interacting with the top cover Collaborate to hold the sensor box. Such as the holding device described in claim 1, wherein: An annular sealing member is provided on the outer peripheral surface of the sensor box, and the sealing member seals between the outer peripheral surface of the sensor box and the inner peripheral surface of the body to prevent fluid from flowing from the cylinder. Room leaks. Such as the holding device described in claim 1 or 2, wherein: The top cover has an external threaded part screwed into the body, The holding device further includes a rotation preventing mechanism that prevents the sensor case from rotating relative to the main body.

Images