JP2014177981A - Feeding structure and holding device with feeding structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a feeding structure and a holding device having this feeding structure capable of realizing a powerful holding force and making a size of the device into more compact than that of the prior art.SOLUTION: A chuck comprises a main body, holding claws arranged at the main body and a feeding structure body 20 arranged within a storing chamber of the main body. The feeding structure body 20 comprises a cylinder body 21 formed with a male thread part 22, a first acceptor 27 formed with a through-pass hole 28 and fitted and inserted into one end of the cylinder body 21, a second acceptor 35 fitted and inserted into the other end of the cylinder body 21, an eccentric shaft 40 composed of a base shaft part 41 and an eccentric part 42, an outer tooth gear 45 formed with a through-pass hole 46 passed through front and rear surfaces at its center part and having an eccentric part 42 of the eccentric shaft 40 inserted into the through-pass hole 46, an internal tooth gear 50 having a part of the tooth engaged with a part of the tooth of the outer tooth gear 45, and a screw body 55 formed with a male thread part 56 on the outer peripheral surface of the front end side and engaged with the internal tooth gear 50 at its rear end side.

Description

  The present invention relates to a feed structure used in a feed screw mechanism for moving a claw and a movable body forward and backward, and a gripping device including the feed structure, and in particular, a feed structure including a mechanism for amplifying a gripping force by a claw and a movable body The present invention relates to a gripping device including

  Examples of the gripping device include a chuck that grips an object with a claw threaded with a feed screw, and a vice that grips an object with a movable body screwed to the feed screw and a fixed body fixed to a pedestal. There is.

  By the way, conventionally, when performing an operation that requires a large load on a grasped object, it is necessary to increase the force for grasping the object. Therefore, a grasping device having a mechanism for amplifying the grasping force is provided. Proposed. As such a gripping device, there is a vise disclosed in Japanese Patent Application Laid-Open No. 2000-117646.

  The vise includes a main body on which a guide rail is formed, a fixed jaw integrally formed with the main body, and a movable jaw that is guided by the guide rail and arranged so as to be movable toward and away from the fixed jaw. A spindle that engages the movable jaw and advances and retracts the movable jaw, a force-increasing mechanism that moves the spindle, and the like. The force-increasing mechanism has a rotational force when the drive shaft is rotationally driven using a handle or the like. A pressing member that is amplified by mechanical action and moves with the amplified force is provided, and the spindle is in contact with the pressing member.

  In this vise, the movable jaw is brought close to the fixed jaw by rotating the spindle, and after the object is gripped by the movable jaw and the fixed jaw, the pressing member of the force-increasing mechanism is moved. As a result, the spindle is pressed and moved by the pressing member, the movable jaw engaged with the spindle is further brought closer to the object, and the force for gripping the object is additionally amplified.

  As a mechanism for amplifying the gripping force, configurations as shown in FIGS. 11 and 12 have been proposed. FIG. 11 and FIG. 12 are diagrams showing a part of the chuck 100 provided with a mechanism for amplifying the gripping force.

  As shown in FIGS. 11 and 12, the chuck 100 having such a configuration includes a main body 101, a screw hole 102a, and a gripping claw 102 that advances and retreats along a guide groove formed in the main body 101. The screw screw 102a of the gripping claw 102 is screwed into a feed screw 103 having a hexagonal portion 103a formed at one end thereof, and an arcuate shape fixed to the outer peripheral surface of the main body 101 so as to surround one end portion of the feed screw 103. A first gear 104, a second gear 106 that meshes with the first gear 104 at one end, and a hexagonal portion 105 a to which a handle 107 described later is attached, and a crank 105 that has the other end attached to the hexagonal portion 103 a of the feed screw 103. The handle 107 is attached to the hexagonal portion 105a.

  According to the chuck 100, with the crank 105 and the handle 107 removed, the feed screw 103 is rotated to move the gripping claw 102 toward the object, and the object is gripped by the gripping claw 102. Thereafter, the crank 105 and the handle 107 are attached, and the handle 107 is rotated. As a result, the handle torque is amplified to a predetermined reduction ratio and input to the feed screw 103.

The reduction ratio is as follows. The number of teeth of the first gear is Z1 ′ and the number of teeth of the second gear is Z2 ′.
(Formula 1)
Reduction ratio = Z1 '/ Z2' + 1
From the structural relationship, the reduction ratio is about 5 to 8 times.

  Thus, in any of the above gripping devices, the thrust generated by the feed screw can be additionally amplified.

JP 2000-117646 A

  However, since the vise has a structure including a force-increasing mechanism having a pressing member in contact with the spindle on one end side of the spindle, the entire structure of the vice is larger by the amount of the power-increasing mechanism. There is a problem.

  Further, in the chuck provided with the mechanism for amplifying the gripping force, as described above, the thrust generated by the feed screw can be additionally amplified and the object can be gripped with a strong gripping force. There is a limit to the force that can be amplified due to the structural relationship. Therefore, there is a problem that it cannot be used for an operation of applying a larger load to the grasped object.

  The present invention has been made in view of the above circumstances, and includes a feeding structure that can express a gripping force stronger than before and that can make the entire apparatus more compact than before. The purpose is to provide a gripping device.

The present invention for solving the above problems is as follows.
A cylindrical body in which a male screw portion is formed on the outer peripheral surface and a female screw portion is formed on at least a part of the inner peripheral surface;
A through hole is formed in the central portion, and a first receiver inserted into one end of the cylindrical body in a state where the axial line of the through hole is coaxial with the axial line of the cylindrical body;
A second receiver inserted into the other end of the cylindrical body;
A male screw portion formed on the outer peripheral surface is disposed between the first receiver and the second receiver in the cylindrical body in a state of being engaged with a female screw portion formed on the inner peripheral surface of the cylindrical body. A screw body having a receiving hole formed on a surface thereof facing the first receiver;
An eccentric shaft comprising a base shaft portion and an eccentric portion eccentric with respect to the axis of the base shaft portion, wherein both ends of the base shaft portion are rotatably inserted into the through hole of the first receiver and the receiving hole of the screw body, respectively. ,
In a state in which teeth are formed on the inner peripheral surface so as to be coaxial with the outer peripheral surface and engaged with the screw body so as to be rotatable integrally with the cylindrical body around the axis of the cylindrical body, An internal gear disposed between the first receiver and the screw body;
A tooth portion is formed on the outer peripheral surface, a through hole penetrating the front and back is formed in the center portion, a part of the tooth portion meshes with a part of the tooth portion of the internal gear, and the through hole With the eccentric portion of the eccentric shaft being rotatably inserted, it comprises an external gear disposed in the ring of the internal gear,
The cylindrical body engages with the first receiver so as to be rotatable integrally with the first receiver around the axis of the cylindrical body,
In the surface of the first receiver facing the external gear, a recess that is open to the surface is formed,
A convex portion that is loosely fitted into the concave portion is formed on a surface of the external gear that faces the first receiver.
The number of teeth of the internal gear is related to the feed structure that is larger than the number of teeth of the external gear.

The feeding structure;
A body having at least two guide grooves provided radially around a predetermined point on the surface;
At least two gripping claws provided so as to be engaged with the respective guide grooves of the main body, provided so as to be capable of moving forward and backward along the guide grooves, and having an internal thread portion formed along the guide grooves; A gripping device comprising:
In the feed structure, the first receiver and the second receiver are rotatably supported, and the external thread portion formed on the outer peripheral surface of the cylindrical body is screwed to the internal thread portion of the gripping claw, The present invention relates to a gripping device disposed in the guide groove and below the gripping claw.

  According to the feeding structure according to the present invention having the above-described configuration and the gripping apparatus having the same, first, an object is arranged in the vicinity of a predetermined point of the main body. Examples of the shape of the object include a cylindrical shape, a polygonal column shape, and a cylindrical shape. When gripping an object having such a shape, each gripping claw is placed in front of the main body in advance. Set it in the retracted position.

  Then, by rotating the first receiver, the cylindrical body that engages with the first receiver and rotates integrally with the first receiver around the axis is rotated in the same direction. The gripping claws having the female threaded portion screwed into the male threaded portion on the outer peripheral surface of the cylindrical body are moved (advanced) along the guide groove, and the respective gripping claws are brought into contact with the object. Rotate and grip the object with each gripping claw. Since the convex portion of the external gear is loosely fitted in the concave portion of the first receiver, the external gear rotates in the same direction following the rotation of the first receiver. At the same time, the internal gear meshed with the external gear also rotates in the same direction, and the screw body engaged with the internal gear also rotates in the same direction.

  Next, the eccentric shaft is rotated. As a result, the external gear into which the eccentric portion of the eccentric shaft is inserted performs a turning motion centered on the shaft center of the base shaft portion and the eccentric amount of the eccentric portion as a radius, and is engaged with the external gear. The gear rotates in the same direction by one tooth per one rotation of the eccentric shaft.

Here, such a mechanism is called a so-called hypocycloid mechanism, and the reduction ratio in this hypocycloid mechanism is such that the number of teeth of the external gear is Z1, and the number of teeth of the internal gear is Z2.
(Formula 2)
Reduction ratio = Z1 / (Z2-Z1) +1
It depends on. That is, a large reduction ratio can be obtained by increasing the number of teeth of both gears and increasing the number of teeth of the internal gear than the number of teeth of the external gear. When the number of teeth of the internal gear is constant, the largest reduction ratio can be obtained when the number of teeth of the internal gear is one more than the number of teeth of the external gear. Specifically, when the number of teeth of the internal gear is 30 and the number of teeth of the external gear is 28, the reduction ratio is 16, whereas the number of teeth of the internal gear is 30, When the number of gear teeth is 29, the reduction ratio is 30, and the reduction ratio is significantly increased by increasing the number of teeth of the internal gear by one more than the number of teeth of the external gear.

  Then, when the internal gear which has obtained a large rotational torque by the hypocycloid mechanism rotates, the screw body engaged with the internal gear rotates in the same direction, and the cylindrical body in which the female screw part is screwed with the male screw part of the screw body is pivoted. Move (advance) with great force along the direction. Thereby, a large force is added to the force with which the gripping claws grip the object, the gripping force is amplified, and the object is gripped with a stronger gripping force.

  Thus, according to the gripping device according to the present invention, by incorporating a so-called hypocycloid mechanism inside the feed structure, a large force can be added to the force for gripping the target, and the target can be easily Can be gripped with a stronger gripping force than before, and the entire gripping device can be made more compact than before.

The gripping device is
The feeding structure;
A body having at least one guide groove provided on the surface;
At least one gripping body provided on the surface of the main body so as to be fixed or movable;
And at least one gripping claw having an internal thread portion formed along the guide groove and disposed so as to be engaged with the guide groove of the main body. A gripping device,
The guide groove arranging direction and the gripping body moving direction are set radially about a predetermined point on the surface of the main body,
In the feed structure, the first receiver and the second receiver are rotatably supported, and the external thread portion formed on the outer peripheral surface of the cylindrical body is screwed to the internal thread portion of the gripping claw, The gripping device may be configured to be disposed in the guide groove and below the gripping claw.

  According to the gripping device provided with this feed structure, first, an object is arranged near a predetermined point of the main body. At this time, in the same manner as described above, each gripping claw is previously placed in a retracted position closer to the outside of the main body. Further, when the gripper is movable, the gripper is also located at a retracted position closer to the outside of the main body.

  Next, the first receiver is rotated, engaged with the first receiver, and a cylindrical body that can rotate integrally with the first receiver around the axis is rotated in the same direction. The gripping claw, in which the female thread portion is engaged with the male thread portion of the cylindrical body, is moved along the guide groove to bring the gripping claw into contact with the object. Further, when the gripping body is movable, the gripping body is also moved and brought into contact with the object. Thereafter, the first receiver is further rotated and the object is gripped by the gripping claws and the gripping body.

  Thereafter, the eccentric shaft is rotated, and the external gear into which the eccentric portion of the eccentric shaft is inserted is turned around the shaft center of the base shaft portion and the eccentric amount of the eccentric portion as a radius as described above. Moreover, the internal gear meshed with the external gear is rotated by the large torque obtained by the hypocycloid mechanism, and the screw body engaged with the internal gear is rotated in the same direction. As a result, the cylindrical body in which the internal thread portion is screwed to the external thread portion of the thread body moves (advances) along the axial direction with a large force, and a large force is added to the force with which the gripping claws grip the target object. Is gripped by the amplified gripping force.

  The cylindrical body in the feed structure is formed with a small-diameter portion that is radially reduced in diameter at least at a part of the inner peripheral surface, and the female thread portion is formed on the inner peripheral surface of the small-diameter portion. The receiver is formed with a flange portion that is radially expanded at least in part, and a spring is disposed between the end surface of the small diameter portion of the cylindrical body and the end surface of the flange portion of the second receiver. It is preferable to urge the cylindrical body toward one end side by a spring. In this way, when the gripping force is relaxed, the cylindrical body can be smoothly moved (retracted) by the biasing force of the spring.

  As described above, according to the feeding structure according to the present invention and the gripping device including the same, it is possible to apply a strong gripping force to an object more easily than in the past, and further to make the entire device compact. can do.

It is a front view of the chuck concerning one embodiment of the present invention. It is sectional drawing of arrow AA in FIG. It is sectional drawing of arrow BB in FIG. It is the side view seen from the arrow C direction in FIG. It is sectional drawing which shows a feed structure. It is the side view seen from the arrow D direction in FIG. It is sectional drawing of arrow EE in FIG. It is sectional drawing of the arrow FF in FIG. It is sectional drawing of the arrow GG in FIG. It is sectional drawing which shows a feed structure. It is sectional drawing which shows a part of conventional chuck | zipper. It is a side view which shows a part of conventional chuck | zipper.

  Hereinafter, a gripping device according to a specific embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 to 4, the chuck 1 of the present example includes a disc-shaped main body 2 in which a workpiece is disposed at the center, and an equal interval in the circumferential direction of the main body 2 (in this example, an interval of 90 °). The four gripping claws 10 having the same shape for gripping the workpiece disposed in the central portion and the radial direction of the main body 2 are disposed along the radial direction of the main body 2. The four gripping claws 10 are each composed of four feeding structures 20 that advance and retract.

  The radial direction means a direction that spreads radially from the center of the main body 2.

  In the main body 2, four guide grooves 3 having a substantially T-shaped cross section are formed on the front end surface portion thereof along the radial direction and at equal intervals in the circumferential direction (90 ° interval in this example). Has been. Further, the main body 2 is formed with a storage chamber 4 having a circular arc shape in cross section in which each of the four feeding structures is disposed, below the guide groove 3 so as to communicate with the guide groove 3. . In addition, on both sides of the upper opening of each guide groove 3, a lift prevention plate 5 for preventing the gripping claws engaged with the guide groove 3 from lifting is fixed by bolts 6.

  The four gripping claws 10 are formed with arc-shaped female screw portions 11 on the lower surface thereof along the advancing and retreating directions, and engaging with the guide grooves 3 on both lower side surfaces of the gripping claws 10. The convex part 12 is formed along the advancing / retreating direction. Thus, each gripping claw 10 is guided by the guide groove 3 and moves along the radial direction.

  Next, the feed structure 20 will be described in detail with reference to FIGS.

  The feed structure 20 has a cylindrical body 21 having a male screw portion 22 formed on the outer peripheral surface and a through hole 28. One end side of the cylindrical body 21 (on the left side of the drawing in FIG. A first receiver 27 inserted into the side) and a second receiver inserted into the other end side of the cylindrical body 21 (the right side in FIG. 5, hereinafter referred to as “front end side”). 35, a base shaft portion 41 and an eccentric portion 42 eccentric to the axis of the base shaft portion 41, and an eccentric shaft 40 in which the base shaft portion 41 is inserted into the through hole 28 of the first receiver 27, and an outer peripheral surface. A tooth portion is formed, and a through hole 46 penetrating the front and back is formed in the center portion. An external gear 45 in which the eccentric portion 42 of the eccentric shaft 40 is rotatably inserted into the through hole 46, and an inner peripheral surface And a part of the tooth part meshes with a part of the tooth part of the external gear 45, and the front end surface. An internal gear 50 in which the key portion 51 is formed, and a male screw portion 56 is formed on the outer peripheral surface of the front end side, and a key groove 58 to be engaged with the key portion 51 of the internal gear 50 is formed in the peripheral portion of the rear end surface. And a screw body 55.

  In the cylindrical body 21, a small diameter portion 23 whose inner diameter is radially reduced is formed on the inner peripheral surface of the intermediate portion, and a female screw portion 24 is formed on the inner peripheral surface of the small diameter portion 23. The cylindrical body 21 is formed with medium diameter portions 24a and 24b having a larger inner diameter than the small diameter portion 23 on both sides of the small diameter portion 23 toward the front end side and the rear end side, respectively, A large diameter portion 25a having an inner diameter larger than that of the medium diameter portion 24a is further formed. Further, a key groove 26 is formed on the inner peripheral surface of the middle diameter portion 25b on the rear end side.

  The first receiver 27 is made of a member having a circular shape in a longitudinal sectional view, and a circular concave portion 29 opened to the front end surface is formed at equal intervals in the circumferential direction so as to surround the through hole 28 on the front end surface thereof. A hexagonal portion 30 is formed on the rear end side. In addition, a flange portion 31 having a radially increased diameter is formed at an intermediate portion of the first receiver 26, and a rectangular key body 32 is fixed to the outer peripheral surface of the flange 31 with a bolt. ing. The first receiver 27 has the cylindrical body 21 so that the axis of the through hole 28 is coaxial with the axis of the cylindrical body 21 in a state where the key body 32 and the key groove 26 of the cylindrical body 21 are engaged. The first receiving body 27 and the cylindrical body 21 are integrally rotated around the axis of the cylindrical body 21. Note that the longitudinal direction of the key body 32 is shorter than the longitudinal direction of the key groove 26, and the cylindrical body 21 and the first receiver 27 are engaged by the engagement of the key body 32 and the key groove 26. Are restricted from rotating with respect to each other around the axis, while being movable in the direction along the axis.

  The second receiver 35 is made of a member having a circular shape in a longitudinal sectional view, and a flange portion 36 having a radially increased diameter is formed at an intermediate portion thereof. The second receiver 35 is formed of a flange portion 36. Is inserted into the cylindrical body 21 with a spring 39 interposed between the rear end face of the cylindrical body 21 and the front end face of the small diameter portion 23 of the cylindrical body 21. Thereby, the cylindrical body 21 is biased toward the rear end side. Further, a stepped portion 37 whose diameter is increased in the radial direction is formed on the outer peripheral surface on the front end side of the flange portion 36, and the stepped portion 37 is inserted in the state where the second receiver 35 is fitted into the cylindrical body 21. A gap is formed between the rear end surface of the cylindrical body 21 and the front end surface of the medium diameter portion 24a of the cylindrical body 21.

  As described above, the eccentric shaft 40 includes the base shaft portion 41 and the eccentric portion 42 formed eccentrically with respect to the axis of the base shaft portion 41 at the axial intermediate portion of the base shaft portion 41. The rear end side is rotatably inserted into the through hole 28 of the first receiver 27. Further, an insertion port 43 is opened at the rear end surface of the eccentric shaft 40, and the eccentric shaft 40 can be rotated by inserting a handle into the insertion port 43 as appropriate. In FIG. 9, M <b> 1 indicates the axis of the base shaft portion 41, and M <b> 2 indicates the axis of the eccentric portion 42.

  The external gear 45 is formed with a through hole 46 penetrating the front and back at the center, and a circular convex portion 47 having a smaller diameter than the concave portion 29 of the first receiver 27 is formed on the rear end surface thereof. Has been. The external gear 45 is formed so that the convex portion 47 is loosely fitted in the concave portion 29 of the first receiver 27 and the eccentric portion 42 of the eccentric shaft 40 is inserted into the through hole 46. It is arranged in the space. The external gear 45 of this example has 29 teeth on the outer peripheral surface thereof.

  In the internal gear 50, the central axis of the outer peripheral surface and the central axis of the inner peripheral surface are coaxial, a tooth portion is formed on the inner peripheral surface, and a part of the tooth portion is a tooth of the external gear 45 It is disposed in the internal space of the cylindrical body 21 in a state of being engaged with a part of the portion. The internal gear 50 of this example has 30 teeth formed on the inner peripheral surface thereof.

  As described above, the screw body 55 has the male screw portion 56 formed on the front end side and the flange portion 57 formed on the rear end side, and the rear end surface has a key groove on the periphery thereof. 58 is formed, and a receiving hole 59 into which the front end side of the eccentric shaft 40 is rotatably inserted is formed at the center. The threaded body 55 has a male threaded portion 56 screwed into a female threaded portion 24 formed in the small diameter portion 23 of the cylindrical body 21, and the key portion 51 of the internal gear 50 is engaged with the key groove 58. The end surface and the front end surface of the internal gear 50 are in contact with each other and are disposed in the internal space of the cylindrical body 21.

  A liner 60 and a bearing 61 are interposed between the rear end surface of the internal gear 50 and the front end surface of the flange portion 31 of the first receiver 27, and the internal gear 50, the screw body 55, and the liner are interposed. 60 is connected by a bolt 62. Further, the liner 60 is in contact with the rear end surface of the internal gear 50, and the bearing 61 is in contact with the front end surface of the flange portion 31 in the first receiver 27.

  The feeding structure 20 having the above-described configuration is provided in the storage chamber 4 in which the rear end surface of the flange portion 31 in the first receiver 27 and the front end surface of the flange portion 36 in the second receiver 35 are formed in the main body 2. It is accommodated in the storage chamber 4 in a state of being in contact with the inner wall surface. The rear end side of the first receiver 27 and the front end side of the second receiver 35 are rotatably supported by the main body 2 and a support member 65 attached to the main body 2, respectively.

  Next, a process of gripping a workpiece by the chuck 1 having the above configuration will be described.

  First, a workpiece is placed near the center of the main body. At this time, each gripping claw 10 is positioned at an appropriate retracted position on the outer side in the radial direction so that a workpiece can be arranged.

  Next, a handle is appropriately attached to the hexagonal portion 30 of the first receiver 27, and the first receiver 27 is rotated. As a result, the key body 32 of the first receiver 27 engages with the key groove 26, and the cylindrical body 21 configured to rotate integrally with the first receiver about its axis rotates in the same direction. Each gripping claw 10 in which the female screw portion 11 is screwed into the male screw portion 22 of the cylindrical body 21 moves toward the center side of the main body 2. And after making each holding claw 10 contact | abut to a workpiece | work, the 1st receiving body 27 is further rotated and a workpiece | work is gripped by the four holding claws 10. FIG.

  The convex portion 47 of the external gear 45 is loosely fitted in the concave portion 29 of the first receiver 27. When the first receiver 27 is rotated, the first receiver 27 is rotated. The external gear 45 also rotates in the same direction so as to follow, and the internal gear 50 meshed with the external gear 45 also rotates in the same direction.

  Thereafter, a handle is appropriately inserted into the insertion port 43, and the eccentric shaft 40 is rotated by rotating the handle. Thereby, the external gear 45 in which the eccentric portion 42 is inserted performs a turning motion with the radius of the eccentric amount of the eccentric portion 42 with respect to the base shaft portion 41 about the shaft center M1 of the base shaft portion 41 of the eccentric shaft 40. And by this turning motion, the internal gear 50 meshed with the external gear 45 rotates in the same direction by one tooth per one rotation of the eccentric shaft.

  Such a mechanism is generally known as a hypocycloid mechanism, and this hypocycloid mechanism can easily obtain a large reduction ratio.

That is, the reduction ratio in the hypocycloid mechanism is such that the number of teeth of the external gear 45 is Z1, and the number of teeth of the internal gear 50 is Z2.
(Formula 2)
Reduction ratio = Z1 / (Z2-Z1) +1
By increasing the number of teeth of the internal gear 50 from the number of teeth of the external gear 45 and increasing the number of teeth of both gears, a large reduction ratio can be obtained. In addition, when the number of teeth of the external gear 45 or the internal gear 50 is constant, the largest reduction ratio can be obtained from Equation 2 from the number of teeth of the external gear 45 based on the number of teeth of the external gear 45. This is also the case when there is only one sheet.

In the chuck 1 of this example, as described above, the number of teeth of the external gear 45 is 29, and the number of teeth of the internal gear 50 is 30,
(Formula 3)
Reduction ratio = 29 / (30-29) +1
Thus, the reduction ratio is 30.

  Therefore, by rotating the eccentric shaft 40, the rotational torque input from the eccentric shaft 40 is amplified by 30 times by the hypocycloid mechanism, and the internal gear 50 is rotated by the amplified rotational torque. The screw body 55 in which the key portion 51 of the toothed gear 50 is engaged with the key groove 58 is also rotated in the same direction with the amplified rotational torque.

  When the screw body 55 rotates, the cylindrical body 21 in which the female screw portion 24 is screwed to the male screw portion 56 of the screw body 55 moves forward with a large force along the axial direction (see FIG. 10). As a result, a large force is applied to the gripping claw 10 in which the female threaded portion 11 is screwed into the male threaded portion 22 of the cylindrical body 21, and the gripping claw 10 grips the object. Is strongly gripped.

  When removing the workpiece from the chuck 1, first, the eccentric shaft 40 is rotated in the opposite direction to the above, and the cylindrical body 21 is retracted. At this time, a spring 39 is provided between the front end surface of the small-diameter portion 23 in the cylindrical body 21 and the rear end surface of the flange portion 36 in the second receiver 35, and the cylindrical body 21 is biased toward the rear end side. Therefore, the cylindrical body 21 moves backward smoothly.

  Thereafter, the first receiver 27 is rotated in the direction opposite to the above to rotate the cylindrical body 21 in the same direction, and the gripping claws 10 are retracted, that is, moved away from the workpiece. Thereby, the gripping by the gripping claws 10 is released, and the workpiece can be removed from the chuck 1.

  As described above, according to the chuck 1 of this example, the eccentric shaft 40 is rotated after the workpiece is gripped by the gripping claws 10 by rotating the first receiver 27 and rotating the cylindrical body 21. Thus, the screw body 55 rotates with the rotational torque amplified by a so-called hypocycloid mechanism built in the feed structure 20. Then, when the cylindrical body 21 screwed into the screw body 55 moves forward, the gripping claw 10 moves forward in the same direction. Therefore, a large force is added to the force for gripping the workpiece, and the workpiece can be gripped strongly by the amplified force.

  Further, since a mechanism for amplifying the gripping force is built in the feed structure 20, the apparatus can be miniaturized.

  The specific embodiments of the present invention have been described above, but the specific modes that the present invention can take are not limited thereto.

For example, in the above example, the combination of the external gear 45 and the internal gear 50 is a combination with a reduction ratio of 30, but is not limited to this, and the number of teeth that varies as appropriate according to the required reduction ratio. It is sufficient to combine the gears.
In the above example, the workpiece is gripped by the four gripping claws 10. However, the workpiece may be gripped by gripping claws of more or less.

  Further, the chuck 1 in the above example grips the workpiece by the four gripping claws 10 that move forward and backward. For example, the workpiece is formed by two gripping claws 10 and two gripping bodies fixed to the surface of the main body 2. You may make it hold | grip. In this case, the gripping claws 10 and the gripping body are opposed to each other, and they are arranged at equal intervals in the circumferential direction of the main body 2.

  In this case, the work is placed on the main body 2 in a state where the work is brought into contact with the two gripping bodies. Next, the first receiver 27 is rotated to rotate the cylindrical body 21, and the gripping claws 10 are moved toward the workpiece. Then, after bringing the gripping claws 10 into contact with the workpiece, the cylindrical body 21 is further rotated, and the workpiece is gripped by the two gripping claws and the two gripping bodies.

  Thereafter, by rotating the eccentric shaft 40 of the feed structure 20, the screw body 55 is rotated with the rotational torque amplified by the hypocycloid mechanism in the feed structure 20. Then, when the cylindrical body 21 in which the female screw portion 24 is screwed into the male screw portion 56 of the screw body 55 moves forward, the gripping claw 10 moves forward toward the workpiece. Therefore, a large force is added to the force for gripping the workpiece, and the workpiece is strongly gripped with the amplified force.

  Note that the numbers of the gripping claws 10 and the gripping bodies are not limited to the above. That is, one grip claw 10 and two grip bodies may be provided. Alternatively, one gripping claw 10 and one gripping body may be provided, and both may be arranged to face each other. In this case, it is understood that the present invention is embodied as a vice.

DESCRIPTION OF SYMBOLS 1 Chuck 2 Main body 3 Guide groove 4 Storage chamber 10 Holding claw 11 Female thread part 20 Feed structure 21 Cylindrical body 22 Male thread part 24 Female thread part 27 1st receiver 29 Recessed part 30 Hexagon part 35 2nd receiver 40 Eccentric shaft 41 Base shaft part 42 Eccentric portion 45 External gear 47 Convex portion 50 Internal gear 55 Screw body 56 Male thread portion

Claims (5)

A cylindrical body in which a male screw portion is formed on the outer peripheral surface and a female screw portion is formed on at least a part of the inner peripheral surface;
A through hole is formed in the central portion, and a first receiver inserted into one end of the cylindrical body in a state where the axial line of the through hole is coaxial with the axial line of the cylindrical body;
A second receiver inserted into the other end of the cylindrical body;
A male screw portion formed on the outer peripheral surface is disposed between the first receiver and the second receiver in the cylindrical body in a state of being engaged with a female screw portion formed on the inner peripheral surface of the cylindrical body. A screw body having a receiving hole formed on a surface thereof facing the first receiver;
An eccentric shaft comprising a base shaft portion and an eccentric portion eccentric with respect to the axis of the base shaft portion, wherein both ends of the base shaft portion are rotatably inserted into the through hole of the first receiver and the receiving hole of the screw body, respectively. ,
In a state in which teeth are formed on the inner peripheral surface so as to be coaxial with the outer peripheral surface and engaged with the screw body so as to be rotatable integrally with the cylindrical body around the axis of the cylindrical body, An internal gear disposed between the first receiver and the screw body;
A tooth portion is formed on the outer peripheral surface, a through hole penetrating the front and back is formed in the center portion, a part of the tooth portion meshes with a part of the tooth portion of the internal gear, and the through hole With the eccentric portion of the eccentric shaft being rotatably inserted, it comprises an external gear disposed in the ring of the internal gear,
The cylindrical body engages with the first receiver so as to be rotatable integrally with the first receiver around the axis of the cylindrical body,
In the surface of the first receiver facing the external gear, a recess that is open to the surface is formed,
A convex portion that is loosely fitted into the concave portion is formed on a surface of the external gear that faces the first receiver.
The number of teeth of the internal gear is larger than the number of teeth of the external gear.   The feed structure according to claim 1, wherein the number of teeth of the internal gear is one more than the number of teeth of the external gear. The cylindrical body has a small-diameter portion that is radially reduced in diameter at least at a part of the inner peripheral surface, and the female screw portion is formed on the inner peripheral surface of the small-diameter portion,
The second receiver has at least a flange portion that is radially expanded in diameter,
A spring is disposed between the end surface of the small diameter portion of the cylindrical body and the end surface of the flange portion of the second receiver,
3. The feed structure according to claim 1, wherein the cylindrical body is urged toward the one end side by the spring. A feed structure according to any one of claims 1 to 3;
A body having at least two guide grooves provided radially around a predetermined point on the surface;
At least two gripping claws provided so as to be engaged with the respective guide grooves of the main body, provided so as to be capable of moving forward and backward along the guide grooves, and having an internal thread portion formed along the guide grooves; A gripping device comprising:
In the feed structure, the first receiver and the second receiver are rotatably supported, and the external thread portion formed on the outer peripheral surface of the cylindrical body is screwed to the internal thread portion of the gripping claw, A gripping device disposed in the guide groove and below the gripping claws. A feed structure according to any one of claims 1 to 3;
A body having at least one guide groove provided on the surface;
At least one gripping body provided on the surface of the main body so as to be fixed or movable;
And at least one gripping claw having an internal thread portion formed along the guide groove and disposed so as to be engaged with the guide groove of the main body. A gripping device,
The guide groove arranging direction and the gripping body moving direction are set radially about a predetermined point on the surface of the main body,
In the feed structure, the first receiver and the second receiver are rotatably supported, and the external thread portion formed on the outer peripheral surface of the cylindrical body is screwed to the internal thread portion of the gripping claw, A gripping device disposed in the guide groove and below the gripping claws.

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