JP3846226B2 - Chuck device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chuck device for gripping a part of a workpiece when processing the workpiece.
[0002]
[Prior art]
When machining a workpiece (for example, grinding), the workpiece is gripped by a chuck device. The chuck device generally has a cylindrical shape and a chuck body that is rotated around its axis, and a plurality of claw members that are held and guided by the chuck body and have claw portions that can move to a workpiece gripping position and a workpiece opening position. And a driving mechanism for opening and closing the claw member. Then, by bringing a predetermined tool (for example, a grindstone) into contact with the workpiece held and rotated by the claw member, the outer peripheral surface of the workpiece is processed into a predetermined shape.
[0003]
When a workpiece is processed by a tool, chips are generated from the workpiece, and abrasive grains are generated from the grindstone, which are mixed into the coolant sprayed from the nozzle to the processing site. The coolant mixed with chips and abrasive particles may scatter around the workpiece processing site and enter the gap between the claw member and the guide surface of the chuck body. As a result, the guide surface is damaged, the smooth movement of the claw member is hindered, and the work with the tool becomes insufficient. Conventionally, various measures have been taken to prevent this.
[0004]
For example, the conventional chuck device shown in FIGS. 5 and 6 includes a chuck body 70, a pair of claw members 74, a drive mechanism 78, and a rubber cover 84. The chuck body 70 includes a cylindrical portion 71 and a rectangular plate portion 72, and a cylinder bore 71 a is formed at the center of the cylindrical portion 71. Each claw member 74 is held and guided by a rectangular plate portion 72 and moved in a centripetal direction and a centrifugal direction (ie, radial direction), and a claw that extends from the holding portion 75 and protrudes from the rectangular plate portion 72 and is opposed at a predetermined interval. Part 76.
[0005]
The drive mechanism 78 includes a piston portion 79 that is slidably engaged with the cylinder bore 71 a of the cylindrical portion 71, and a wedge portion 80 having a tapered surface 80 a that engages with the tapered surface 75 a of the holding portion 75. When pressure oil is supplied to and discharged from the cylinder bore 71a through the ports 82a and 82b and the piston portion 79 is moved up and down, the wedge portion 80 moves the pair of claw members 74 to the workpiece gripping position and the workpiece opening position.
[0006]
The rubber cover 84 includes a rectangular bottom portion 85 and a rectangular wall portion 86, and the rectangular wall portion 86 is locked to the rectangular plate portion 72. The rectangular bottom portion 85 is formed with a pair of through-holes 85a through which the claw portions 76 penetrate, and expandable / contractible bellows portions 85b and 85c formed on both sides of the through-hole 85a.
[0007]
In the conventional chuck device, the workpiece W is gripped by the pair of claw members 74 moved in the centripetal direction (the direction toward the center in FIG. 5), and when the chuck body 70 rotates, the workpiece W rotates about its axis. A rotating brush or the like 87 is brought into contact with the processing portion of the workpiece W, and the processing portion is processed into a predetermined shape while spraying coolant from the nozzle 88.
[0008]
When the claw member 74 moves in the centripetal direction, the bellows portion 85b in the middle portion of the rectangular bottom portion 85 is contracted, and the bellows portions 85c on both sides are extended. On the other hand, when moving in the centrifugal direction, the bellows portion 85b at the middle portion extends and the bellows portions 85c on both sides shrink in accordance with the movement. As a result, when the claw member 74 moves, the chips and abrasive particles mixed in the coolant enter the tapered surfaces 75a and 80a in the chuck body 70 from the gap between the claw portion 76 and the edge of the through hole 85a. I'm trying to prevent that.
[0009]
[Problems to be solved by the invention]
In the conventional chuck device, the rubber cover 84 can prevent the chip and abrasive grains having relatively large dimensions (for example, 20 μm or more) from entering the chuck body to some extent. However, it is difficult to sufficiently prevent the rubber cover 84 from penetrating chips and abrasive grains having very small dimensions (for example, 20 μm or less). The reason is that the side surfaces 76a and 76b in the direction orthogonal to the moving direction of the claw portion 76 are sealed. For example, when the claw portion 76 moves in the centripetal direction, the inner side surface 76a is pressed against the edge portion of the bellows portion 85b that shrinks, so that it is difficult to form a gap between the two. However, the edge portions of the bellows portions 85c on both sides cannot sufficiently follow the outer side surface 76b of the claw portion 76, and a gap is easily formed between them. Note that when the claw portion 76 moves in the centrifugal direction, the edge portion of the extending bellows portion 85b cannot sufficiently follow the inner side surface 76a, and a gap is easily formed between them.
[0010]
Chips and abrasive grains mixed in the coolant and entering from the gap enter between the tapered surface 75a of the holding portion 75 and the tapered surface 80a of the wedge portion 80, and damage the tapered surfaces 75a and 80a. As a result, the movement (direction and amount) of the claw member 74 when the wedge portion 75 is lowered becomes inaccurate. In this way, the set position of the workpiece W gripped by the claw member 74 varies, and the processing of the processing site by the brush 87 or the like is insufficient and inaccurate.
[0011]
The present invention has been made in consideration of the above circumstances, and very small dimensions (for example, 20 μm or less) of chips and abrasive particles mixed in the coolant enter the inside of the chuck body, particularly the guide portion of the claw member. It is an object of the present invention to provide a chuck device that can prevent the above-described problem.
[0012]
[Means for Solving the Problems]
The inventor of the present application covers the opening end portion of the chuck body with a cover, passes the claw portion through a through hole formed in the cover, and then the end surface of the claw portion or the holding portion (surface parallel to the moving direction of the claw member). The idea of sealing between the cover and the cover with a sealing member was conceived to complete the present invention.
[0013]
That is, the chuck device of the present invention has a cylindrical shape and rotates around the axis thereof; a holding portion held inside the chuck body; and a workpiece positioned outside the chuck body and gripping a workpiece. A plurality of claw members including a claw portion and a neck portion connecting the holding portion and the claw portion across the end surface of the chuck body; each claw member is opened and closed so that the claw portion takes a workpiece gripping position and a workpiece opening position A driving mechanism for driving; a plurality of through-holes that cover the opening end surface of the chuck body and through which each neck portion penetrates, and each through-hole has a shape and a size that allow movement of each neck portion when each claw member is driven to open and close A cover having a plurality of seal members for sealing a moving space between each neck portion and the peripheral portion of each through-hole, each of the seal members having a hollow disk shape having an inner peripheral surface at a center portion thereof. It consists Jo of rubber, the inner of the sealing member Surface is fitted to the outer peripheral surface of the neck, one surface of the sealing member is pressed against the cover and opposite sides of the claw portion, the outer edge of the other side of the seal member cyclic The small protrusions are formed, and the small protrusions are pressed by the cover to seal the moving space.
[0014]
When gripping and releasing the workpiece, the claw portions of the plurality of claw members move in the centripetal direction and the centrifugal direction in the through hole of the cover. At this time, since the through-hole has a predetermined size and shape, there is no concern that the edge portion prevents the movement of the claw portion. Further, the seal member held by the neck is pressed against the edge of the through hole, and prevents coolant mixed with chips and abrasive grains from entering the chuck body from the gap between the neck and the edge.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the invention are as follows.
<Chuck body>
The chuck body preferably has a cylindrical shape as a whole. A claw member, a drive mechanism, and the like described below are arranged using the hollow portion. The chuck body can be composed of a single member or a plurality of members, and is rotated around its axis by a rotating mechanism when the workpiece is processed.
<Claw member>
Any two or more claw members can be provided. Usually, each claw member has the same configuration and moves, that is, opens and closes in the centripetal direction and the centrifugal direction in synchronization with each other. Each claw member has a holding part, a claw part, and a neck part. The holding part, the claw part, and the neck part may be formed by a single member, or may be formed by two members that respectively correspond to the holding part and the claw part. The holding portion is guided by the guide surface of the chuck body so as to be movable inward and outward in the radial direction without moving in the axial direction, and it is desirable to connect the claw portion to the holding portion via the neck portion. The neck portion has a smaller cross-sectional area than the end surfaces of the holding portion and the claw portion, and as a result, an annular space is formed between the end surface of the holding portion and the end surface of the claw portion.
[0016]
The claw portion is disposed outside the chuck body, and moves in the centripetal direction when gripping the workpiece and moves in the centrifugal direction when released, as the holding portion connected through the neck portion moves. When the claw portion moves in the centripetal direction, the claw member takes the workpiece gripping position, and when moved in the centrifugal direction, takes the workpiece opening position. A workpiece gripping surface corresponding to the shape and length of the workpiece can be formed on the front surface in the centripetal direction of each claw.
[0017]
When the claw member is composed of a first member corresponding to the holding portion and a second member corresponding to the claw portion, the neck portion can be composed of a protrusion formed on the holding portion or the claw portion. The annular space formed around the protrusion can be used for the arrangement of the seal member described below.
<Drive mechanism>
The drive mechanism can be disposed inside and / or outside the chuck body. The drive mechanism only needs to be able to apply a driving force that finally moves the claw portion in the centripetal direction and the centrifugal direction to the claw member, but it is convenient to move the holding portion in the centripetal direction and the centrifugal direction. In that case, a drive mechanism is provided by a rod that is arranged outside and moves in the axial direction of the chuck body, and a conversion and transmission member that is arranged inside and converts the axial movement of the rod into a radial movement and transmits it to the holding portion. Can be configured.
<Cover>
The cover covers the opening end surface of the chuck body, has a shape corresponding to the opening end surface, and a part of the cover is attached to the chuck body. The cover only needs to have at least a portion covering the opening end face, and can be formed into a disk shape, for example. Moreover, it can also be set as the bottomed cylindrical shape which consists of a disk-shaped bottom part and the surrounding wall part extended in the orthogonal | vertical direction from the periphery.
[0018]
The cover has a through hole that allows the neck portion of the claw member to pass therethrough. The number of through holes is equal to the number of neck portions, and the shape, position and direction of the through holes can correspond to the shape, position and direction of the neck portion. However, it is necessary that the through hole does not hinder the movement of the neck when the claw member is driven, and for that purpose, the through hole has a predetermined length in the movement direction of the neck. In the present invention, since the cover does not need to be elastically deformed when the claw member is moved, the cover can be made of a metal that does not elastically deform.
<Seal member>
The seal member is made of a known seal material (for example, rubber), and is attached to the neck portion of the claw member to seal the moving space between the neck portion and the edge of the through hole. Since the seal member cannot be directly inserted into the moving space, it is attached to the neck portion and interposed between the cover and the claw portion or the holding portion. In any case, since the seal member is attached to the neck portion, it moves together with the claw member when the claw member is driven to open and close.
[0019]
The shape of the seal member can be determined corresponding to the shape of the neck and the through hole. For example, the sealing member can have a hollow disk shape, the inner diameter thereof is equal to the outer diameter of the neck, and the outer diameter can be made larger than the maximum diameter of the through hole. The inner peripheral surface of the seal member is fitted to the outer peripheral surface of the neck portion, one end surface is pressed against the claw portion or the holding portion, and the other end surface is pressed against the front or back surface of the cover.
[0020]
【Example】
Embodiments of the present invention will be described below with reference to FIGS. 1, 2, 3, and 4. 1 is a longitudinal sectional view of the chuck device according to the embodiment, FIG. 2 is a longitudinal sectional view in a direction orthogonal to FIG. 1, FIG. 3 is a three-way view in FIG. 1, and FIG. FIG.
[0021]
The chuck device includes a chuck body 10, a claw member 25, a drive mechanism 34, a cover 42, and a seal member 47. As is clear from FIGS. 1 and 2, the chuck body 10 includes a first body 11, a second body 17 above the first body 11, and a third body 21 below the first body 11. Including.
[0022]
The first body 11 includes a first cylindrical portion 12 extending in one direction in the axial direction, a pair of projecting portions 13 extending in the other direction, a first disk portion 14 extending radially outward therefrom, and an axial direction therefrom. It has an extended peripheral wall 15. The second body 17 has a second cylindrical portion 18 and a second disc portion 19 extending radially outward therefrom. The second disc portion 19 overlaps the first disc portion 14, and the second cylindrical portion 18 is fitted to the first cylindrical portion 12. The third body 21 includes an annular base portion 22 and a pair of extension portions 23 extending in the diameter direction therefrom. The upper end portion of the base portion 22 is fitted into the protruding portion 13 of the first body 11, and each extension portion 23 is formed with a long hole 23 a extending and penetrating in the radial direction.
[0023]
Two (a pair) claw members 25 are arranged, and have a symmetric configuration with respect to the axis of the chuck body 10. The claw member 25 includes a holding portion 26 inside the chuck body 10, a claw portion 28 outside, and a neck portion 30 that is located between the two and passes through the opening end surface of the chuck body 10. The holding portion 26 has a rectangular parallelepiped shape, and is movable inward and outward in the radial direction by being guided by a lower surface (guide surface) 22 a formed in a direction orthogonal to the axial direction of the base portion 22. One protrusion (neck) 30 having a circular cross section is formed on the lower surface of the holding portion 26. The claw portion 28 includes a rectangular plate-shaped base portion 28a and a semicircular grip portion 28b extending in the plate thickness direction. The base portion 28a is connected to the protrusion 30 by a bolt 29, and the grip portion 28b has a half-circular grip surface 28c.
[0024]
The drive mechanism 34 includes a rod member 35 inserted through the first body 11 and the second body 12, and an L-shaped crank member 37 disposed between the rod 35 and the claw member 34. A flange portion 35 a formed at the lower end portion of the rod member 35 can come into contact with the end surface of the recess 13 a of the base portion 13 of the first body 11. The rod member 35 is driven by a drive mechanism (not shown) connected to the upper end portion, and moves up and down in the axial direction. The bent portion of the L-shaped crank member 37 is pivotally attached to the protrusion 13 of the first body 11 by a pin 38 and can be pivoted around the pin 38. A roller member 40a pivotally attached to the tip of one arm portion 39a of the crank member 37 engages with a recess 35b formed in the rod member 35, and a roller member 40b pivotally attached to the tip of the other arm portion 39b is provided. It engages with a recess 26 a formed in the holding portion 26. Therefore, when the rod member 35 moves in the axial direction, the holding portion 26, that is, the claw member 25 moves in the radial direction via the pivot of the crank member 37.
[0025]
The cover 42 is made of a thin metal plate and includes a circular bottom wall portion 43 and a peripheral wall portion 44 that rises at a right angle from the peripheral edge portion. The bottom wall 43 has the same diameter as the first body 11 and covers the open end of the chuck body 10. A pair of long holes (through holes) 43a formed in the bottom wall portion 43 at an equal distance from the central portion and penetrating in the thickness direction are long in the diameter direction and short in the direction perpendicular thereto. The short diameter of the long hole 43 a is selected to be approximately equal to the outer diameter of the protrusion 30, and the long diameter is selected so as not to hinder the movement of the protrusion 30 when the claw member 25 is driven.
[0026]
A rectangular plate-shaped guide member 45 is interposed between the bottom wall portion 43 and the holding portion 26. The outer peripheral edge of the guide member 45 is coupled to the bottom wall portion 43, and the protrusion 30 is fitted into a guide hole 45a formed at the center thereof.
[0027]
The seal member 47 is made of a thin plate-like rubber and has a hollow disk shape with a hollow hole 47a formed at the center. As apparent from FIGS. 3 and 4, the inner diameter of the seal member 47 is substantially equal to the outer diameter of the protrusion 30, that is, the shorter diameter of the long hole 43a, and the outer diameter is slightly larger than the longer diameter of the long hole 43a. The hollow hole 47a is fitted into the protrusion 30, the edge of the hollow hole 47a is in elastic contact with the outer surface of the protrusion 30, and the lower end surface 47b is pressed against the upper surface 28d of the base 28a. An annular small protrusion 47 d formed on the outer peripheral edge of the upper surface 47 c of the seal member 47 is pressed against the end surface (lower surface) 43 b of the bottom wall portion 43.
[0028]
Next, the function and effect of this embodiment will be described.
[0029]
When gripping the workpiece W, the rod 35 is raised (see arrow F), and one arm 39a of the crank member 37 is moved upward. As a result, the right crank member 37 pivots clockwise and the left crank member 37 pivots counterclockwise, and the other arm portion 39b moves in the centripetal direction (radially inward). The movement of the arm portion 39 b is allowed by the elongated hole 23 a of the extension portion 23.
[0030]
As a result, the holding portion 26 is moved inward in the radial direction without moving in the axial direction, and the claw portion 28 connected to the holding portion 26 via the protrusion 30 and the bolt 29 moves in the same direction. At this time, the movement of the protrusion 30 is allowed by the moving spaces 43 c on both sides in the longitudinal direction of the long hole 43 a of the cover 42. As a result, the claw member 25 advances to the workpiece gripping position (see the right claw member 25 in FIG. 1). Thus, the workpiece gripping surfaces 28c of the pair of claw portions 28 that are close to each other grip the workpiece W.
[0031]
When the claw member 25 is driven, the seal member 47 fitted to the protrusion 30 moves integrally with the protrusion 30. At this time, the inner peripheral surface 47a of the seal member 47 is fitted to the outer peripheral surface of the protrusion 30, and the lower surface 47b is pressed against the upper surface 28d of the base 28a. Also, slides on the lower surface 42a in a state the upper surface thereof a small protrusion 47d formed in 47c is pressed by the end surface 43 b of the bottom wall portion 43 at a predetermined pressure.
[0032]
As described above, the gap between the protrusion 30 including the working space 43 c and the edge of the long hole 43 a is sufficiently sealed by the seal member 47. Therefore, the coolant mixed with chips and abrasives scattered around the claw member 25 when the workpiece W is machined is an axial gap and a radial gap between the claw member 25 and the cover 42, particularly the protrusion 30 and the through hole. Intrusion into the inside of the chuck main body 10, in particular, the lower surface 22 a of the third body 23 that guides the holding portion 26 of the claw member 25 from the gap between the edge portion 43 a is prevented.
[0033]
Thereafter, the chuck device is rotated, and the workpiece W gripped by the claw member 25 is rotated. A brush 87 (see FIG. 5) is brought into contact with a predetermined processing portion of the rotating workpiece W to process the processing portion into a predetermined shape.
[0034]
When the rod 35 is lowered after the processing of the workpiece W is finished, the crank member 37 pivots in the opposite direction to that described above. As a result, the holding portion 26 of the claw member 25 moves outward in the radial direction, and the claw portion 28 connected thereto via the protrusion 30 and the bolt 29 moves in the same direction. As a result, the claw member 25 moves backward to the workpiece release position (see the left claw member 25 in FIG. 1), and opens the workpiece W.
[0035]
【The invention's effect】
As described above, in the chuck device of the present invention, the neck portion having a smaller area than the other portions is formed between the holding portion of the claw member in the chuck body and the claw portion outside the chuck body. Then, the opening end is covered with a cover in which a through hole having a shape and a length allowing the movement of the neck is formed, and a moving space between the neck and the peripheral edge of the through hole by a seal member attached to each neck Sealed.
[0036]
Therefore, according to the present invention, it is possible to reliably prevent the coolant mixed with chips and the like from entering the guide portion of the claw member inside the chuck body from the gap between the neck portion and the through hole. As a result, the workpiece can be securely held in a predetermined state by the claw member, and the workpiece can be subjected to predetermined processing by the tool.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view in a direction orthogonal to FIG.
FIG. 3 is a three-way view (partially omitted) in FIG. 1;
4 is an enlarged view of a main part in FIG. 1. FIG.
FIG. 5 is a longitudinal sectional view showing one of conventional examples.
6 is a view in six directions (partially omitted) in FIG. 5. FIG.
[Explanation of symbols]
10: Chuck body 11, 17, 21: Body 22a: Guide surface 25: Claw member 26: Holding portion 28: Claw portion 30: Neck portion 37: Drive mechanism 42: Cover 43a: Through hole 47: Seal member W: Workpiece

Claims (5)

A chuck body having a cylindrical shape and rotating about its axis;
A holding part held inside the chuck body; a claw part positioned outside the chuck body for gripping a workpiece; and a neck part located between the holding part and the claw part and crossing an end surface of the chuck body. A plurality of claw members including:
A drive mechanism for opening and closing each of the claw members so that the claw portion takes a workpiece gripping position and a workpiece opening position;
Covering the opening end surface of the chuck body, each neck has a plurality of through holes, and each through hole has a shape and a size that allow movement of each neck when the claw member is opened and closed. A cover,
A chuck device including a plurality of sealing members attached to each neck portion and sealing a moving space between the neck portion and a peripheral edge portion of each through hole,
Each said sealing member is a hollow disc-shape rubber having an inner peripheral surface in the center, the inner peripheral surface of the sealing member is fitted on an outer peripheral surface of the neck, one of the sealing member The surface is pressed against the surface of the claw portion facing the cover, and an annular small ridge is formed on the outer edge of the other surface of the seal member, and the small ridge is pressed against the cover. And the moving space is sealed.   The chuck device according to claim 1, wherein each holding portion is held by the chuck body so as to be movable in a centripetal direction and a centrifugal direction.   The chuck device according to claim 2, wherein each of the neck portions includes a protrusion formed on the holding portion or the claw portion.   The chuck device according to claim 3, wherein each of the through holes is a long hole that is long in a radial direction of the cover.   4. The chuck device according to claim 3, wherein each of the sealing members has an annular shape, is fitted to each of the neck portions, has one end surface pressed by the claw portion, and the other end surface pressed by the cover.

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