JPS62173133A - Clamping mechanism - Google Patents

Abstract

PURPOSE:To automate fitting and removing of each work by inserting a cylinder for accommodation of clamp arm in the center hole of a wheel disc, followed by clamping of the work, and by selecting the shape of the clamp arm optimumly. CONSTITUTION:A work W reference surface 172 is put in contact with a plate 70 in such a way that the reference hole 166 in the work W is loose fitted in the major dia. part 98 of a rod 94. Then a sleeve 82 displaces in the direction of arrow A, and the tip of a collet 74 is pressed outwards in the radial direction. If pressure fluid is introduced to a cylinder, the work W is pressed and retained by said plate 70 and clamp arms 112a, 112b. Here the range of angle in which the clamp arms 112a, 112b rotate is shrunk by selecting the distance H1 of a clamping mechanism 88 to a small value, and thereby the range of displacement of a detent pin 110, i.e. the stroke of a piston 106, is shortened. This allows the clamping mechanism 88 to be designed in a smaller size.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to clamping mechanisms, and more particularly, to
The present invention relates to a clamping mechanism that easily and reliably fixes and fixes a wheel disk of an automobile when processing the wheel disk, and which also enables miniaturization as much as possible.

□ ゛ Generally, in the automobile industry, the various parts that make up automobiles are mass-produced in factories using line production processes. For example, a wheel disk that constitutes a vehicle is cast and then processed to have a hole for attaching it to a drive shaft connected to an engine, a hole for attaching a tube valve, and the like. In this case, various jig devices are employed to position and fix the wheel disk, and an example of this type of jig device is shown in FIG.

That is, reference numeral 2 indicates a base that constitutes a jig device according to the prior art. A workpiece positioning rod 4 is erected at the center of the base 2, and clamp mechanisms 6as6b are provided on both sides of the rod 4. Clamp cylinders 8a, 8 constituting the clamp mechanism 6a16b
Arms 12a are attached to rods 10a and 10b extending from b.
One end of the arm 112b is attached to the arm 12a.
, 12b are swingably supported at substantially intermediate portions thereof via fulcrums 13a, 13b. The arms 12a, 12
Pressing members 14a, 14b are fixed to the other end of the base 2, while a pedestal 16aS16b is provided on the base 2 to correspond to the pressing members 14a, 14b. Further, a hole positioning cylinder 20 is engaged with the rod 4, and a rod 22 extends from the cylinder 2o.

A workpiece W (for example, an aluminum wheel disk) is positioned and fixed to the jig device constructed in this manner. A reference hole 24 is already formed in the center of the workpiece W, and a plurality of stepped hole portions 26, for example, four stepped holes 26, are cast to surround the reference hole 24. The stepped hole portion 26 is a bolt insertion hole portion for attaching the workpiece W to the drive shaft side, and in order to perform chamfering etc., each stepped hole portion 26 is provided with a first screw with a predetermined tool on both sides thereof. And a second processing is performed.

Therefore, the rod 4 is fitted into the reference hole 24, and the cylinder 20 is driven to fit the rod 22 into the negative stepped hole 26. This positions the workpiece W and the stepped hole 26. Next, the clamp cylinders 8a, 8b constituting the clamp mechanism 68.6b are driven, and the rod 10a,
10b is displaced upward in the figure, and the arms 12a, 1
2b, the pressing members 14a, 14b and the pedestal 16a
, 16b press and hold one side outer peripheral portion 28a of the workpiece W.

After positioning and holding the workpiece W on the jig device in this manner, the cylinder 2o is driven to displace the rod 22 downward and remove the rod 22 from the - stepped hole 26. Then, a plurality of stepped holes 26 are formed by the rotary tool 29.
The first processing is performed on.

After performing the first processing on the workpiece W, the clamping mechanism 6a
, 6b to press the pressing members 14a, 14b and the pedestal 16.
a and 16b on the outer peripheral portion 28a, and then remove the workpiece W from the jig device, turn it over, and position and fix it on another jig device (not shown).

In this case, the other jig device is configured similarly to the jig device shown in FIG.
The shape of is selected corresponding to the other side outer peripheral portion 28b of the workpiece W.

Therefore, after fixing the workpiece W in an inverted state on another jig device, a second machining is performed on the stepped hole portion 26 from the opposite direction to the first machining using a rotary tool (not shown) to form each step. The machining of the hole portion 26 is completed.

In this way, the clamp mechanisms in conventional jig devices clamp the outer circumference of the work, so each clamp mechanism must be spaced apart according to the outer diameter of the work. The device itself becomes quite large. Moreover, if the workpieces have different sizes, it is necessary to prepare two jig devices each with a clamping mechanism that corresponds to the dimensions of each workpiece, which increases the manufacturing cost of the jig devices. This causes the inconvenience of doing so.

Furthermore, when attaching a workpiece to the jig device, a rod is fitted into a reference hole in the center of the workpiece, and the outer circumference of the workpiece is engaged with a clamp mechanism. Therefore, the mounting work of the workpiece becomes complicated, and for example, it is impossible to meet the demand for automating the mounting work.

The present invention has been made to overcome the above-mentioned disadvantages. For example, the cylindrical body housing the lamp arm can be opened and closed by using a hole formed in the center of a workpiece such as a wheel disk. After inserting the work into the hole, operate the clamp arm to clamp the work, and
By suitably selecting the shape etc. of the clamp arm, it is possible to extremely simplify the attachment/detachment work of the workpiece and easily achieve automation of the attachment/detachment process. It is an object of the present invention to provide a lamp mechanism that can be made as compact as possible.

In order to achieve the above object, the present invention includes: a cylindrical body having a diameter smaller than the diameter of a hole formed in a workpiece; a rod member that engages with an actuator and is disposed in the cylindrical body so as to be able to move forward and backward; one or more clamp arms that engage with a pin member provided at one end of the rod member and are swingably attached to the cylindrical body via a fulcrum pin; The distance between the workpiece pressing surface and the fulcrum pin in the axial direction of the rod member is smaller than the distance between the fulcrum pin and the pin member in the axial direction of the rod member, and the rod member is moved under the action of the actuator. The clamp arm is displaced in one direction to accommodate the clamp arm inside the cylindrical body, and the cylindrical body is inserted into the hole of the workpiece, and then the rod member is displaced in the other direction under the action of the actuator, and the clamp arm is disposed inside the cylindrical body. The workpiece pressing surface is exposed to the outside of the cylindrical body to press and hold the workpiece.

Next, preferred embodiments of a jig device incorporating a clamp mechanism according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 2, reference numeral 30 indicates a double-ended machine tool on which the jig device is installed. On the base 32 constituting the double-headed single machine tool 30, transport tables 34a and 34b are mounted on both the left and right sides in the figure so as to be movable forward and backward, respectively. First and second tool devices 36a and 36b are provided on the conveyance tables 34a and 34b, respectively, facing each other.

Therefore, a jig device 40 is disposed approximately at the center of the base 32. In this case, the jig stand 4 constituting the jig device 40
2 is mounted on a base 44, and the base 44 is rotatably supported on a shaft 46 fixed to the base 32.

In FIGS. 3 and 4, the jig table 42 has a base portion 48 fixed to the base 44 via a plurality of bolts 47.
and a support portion 50 that is erected on one end side of the base portion 48 so as to be perpendicular thereto. First guide cylindrical parts 52a, 52b are formed on both sides of the support part 50 to bulge in the horizontal direction, and second guide cylindrical parts 56a, 56b are formed above the cylindrical parts 52a, 52b. do.

In this case, the cylindrical portions 56a and 56b are
It bulges in the opposite direction to 2a and 52b (see Figure 4).

Furthermore, a mounting base 58 is formed at the upper part of the support part 50 so as to bulge out in the same direction as the cylindrical parts 52a and 52b.

As shown in FIGS. 4 and 5, a hole 60 is formed in the center of the mounting base 58 and is oriented in the axial direction.
A cylinder chamber 62 having a large diameter communicates with the end portion of the cylinder 0 through a stepped portion. The cylinder chamber 62 is provided with a fluid supply port (not shown), and a hole with a larger diameter communicates with the end of the cylinder chamber 62 via a step (
(not shown). Further, grooves 64a to 64d are formed in the mounting base 58 radially outward from the center of the hole 60, spaced apart at equal intervals, and extending along the axial direction (see FIG. 3), the grooves 64a to 64d are for supporting. The back surface of the portion 50 is in communication with the outside. A plate 66 is fixed to the tip of the mounting base 58 via bolts (not shown), and a stepped hole 68 is formed in the center of the plate 66. Furthermore, this plate 6
A workpiece contacting plate 70 is attached to the workpiece 6 via bolts (not shown). A workpiece positioning mechanism 72 is disposed to fit into the stepped hole 68 of the plate body 66.

A collet 74 constituting the workpiece positioning mechanism 72 is formed with a stepped portion 76 corresponding to the stepped hole portion 68, and a plurality of slits 78 are formed in the outer circumference of the collet 74 oriented in the axial direction. . Further, an inclined surface 80 is provided on the inner circumference of one end of the collet 74 and is inclined radially inward (see FIGS. 6a and 6b). Therefore,
The sleeve member 82 is fitted into the collet 74. A piston portion 84 that fits into the cylinder chamber 62 of the mounting base 58 is formed at one end of the outer circumference of the sleeve member 82, and a cylindrical portion 85 having a small diameter is formed at one end of the piston portion 84 via a stepped portion. do. The cylindrical portion 85 fits into the hole 60, and has an inclined surface 86 formed at one end thereof corresponding to the inclined surface 80 of the collet 74 (see FIGS. 6a and 6b).
reference).

On the other hand, a hole (not shown) communicating with the cylinder chamber 62 has a cylinder member 8 constituting a clamp mechanism 88 according to the present invention.
9 is fitted and installed. A cylinder chamber 90 is formed in the center of the cylinder member 89, and this cylinder chamber 90
A mounting hole 92 communicates with one end of the holder through a small diameter hole. One end of a rod member 94 is fitted into the hole 92, and the rod member 94 is fixed to the cylinder member 89 via a bolt (not shown). The rod member 94 includes a cylindrical portion 96 that fits into the sleeve member 82, and a large diameter portion 98 formed at one end of the cylindrical portion 96. In this case, the diameter of the large diameter portion 98 is equal to the diameter of the workpiece described later. It is selected to be smaller than the diameter of the reference hole. A hole 100 is formed in the central portion of the rod member 94 along its axial direction, and the hole 100
communicates with a hole 102 having a larger diameter. Further, in the large diameter portion 98, a predetermined length is cut out along the axial direction, and grooves 104a and 104b are formed at eccentric and symmetrical positions with respect to the radial direction (see FIG. 5).
.

Therefore, the piston member 106 is disposed in the cylinder member 89. A first extending from one end of the piston member 106
The rod 108 fits into the hole 100 of the rod member 94, and a plate-like portion 109 is formed at its tip by cutting out both sides of the outer circumference. An engagement pin 110 is fitted into a hole (not shown) in the plate-like portion 109, and the clamp arms 112a, 112b are engaged with the engagement pin 110 (see FIGS. 5 and 6a and 6b).

The clamp arms 112a, 112b are formed into a plate shape, and their substantially central portions are swingably supported by the large diameter portion 98 of the rod member 94 via pin members 114a, 114b. Also, each clamp arm 112a.

Pressing surface portions 116a, 116b are formed at one end of 112b, and semi-elliptic openings 118a, 118b are formed at the other end corresponding to the pressing surface portions 116a, 116b. The openings 118a and 118b are the engagement pins 110.
Therefore, the piston member 106
When the clamp arms 112a and 112b are displaced in the directions of arrows A and B, the respective clamp arms 112a and 112b can swing about the pin members 114a and 114b as fulcrums. In this case, as shown in FIG. 6a, when the work W is clamped, the pressing surface portion 116a (116b) and the pin member 114a (11
4b), in the figure, the distance Hf in the horizontal direction (axial direction of the piston member 106) (1, the distance Hf in the vertical direction (radial direction of the piston member 106), and the pin member 114a (11
4b), the horizontal distance H1, and the vertical distance H4 of the engagement pin 110 are selected as shown below. That is, distance H1 is made as short as possible, distance H, < distance H3, distance H2 #distance H4, and distance H3≦distance H4.
The respective distances H+ and Hz 1) are set so that the relationship holds true.
Set In and H4.

On the other hand, one end of an arm member 124 engages with an end of a second rod 120 extending from the other end of the piston member 106 via a pin member 122 . The arm member 124
is swingably supported by the support part 50, and the other end is configured to be engageable with a limit switch 126 provided on the upper part of the support part 50.

By the way, the support portion 50 is provided with, for example, a hole positioning mechanism 12B. As shown in FIG. 7, a fixed shaft 130 constituting the hole positioning mechanism 128 has one end fixed to the support portion 50, and a guide groove 132 is formed in the outer circumference of the fixed shaft 130. In this case, the guide groove 132 extends a predetermined length in the axial direction of the fixed shaft 130, and then curves counterclockwise in the figure. A positioning pin holder 134 is attached to this fixed shaft 130. The positioning pin holder 134 is connected to the fixed shaft 130.
a cylindrical portion 136 that fits into the cylindrical portion 136; a mounting portion 138 that bulges outward from the outer periphery of the cylindrical portion 136;
A guide portion 140 provided on the upper side of the guide portion 140 is included.

A groove 142 is formed at a predetermined angle at the outer peripheral tip of the cylindrical portion 136, and a positioning pin 144 is fixed to the tip of the mounting portion 138. Further, a guide pin 146 is provided in the guide portion 140, and this guide pin 146
fits into the guide groove 132 of the fixed shaft 130. A pair of guide plates 148a are provided on the upper rear end side of the guide portion 140.
, 148b, respectively, and guide plates 148a,
A key 150 fixed to the support part 50 is located between the keys 148b and 148b.
enters and prevents the positioning pin 144 from rotating. Note that a limit switch 152 is provided near the key 150.

Furthermore, a cylinder 154 is disposed below the fixed shaft 130, and a piston rod 156 extending from the cylinder 154 passes through a lid 158.

One end of a guide bar 160 is fixed to the lid body 158, and this guide bar 160 is fitted into a movable plate 162 that is attached to the tip of the piston rod 156.
It prevents the rotation of. A narrow locking part 164 is formed at one end of the moving plate 162.

The jig device incorporating the clamp mechanism according to the present invention is basically constructed as described above, and its operation and effects will be explained next.

Therefore, the operation of positioning and fixing the workpiece W (wheel disk) using the jig device 40 will be explained.

First, the workpiece W is grasped manually or by a robot hand, and the workpiece W is attached to the large diameter portion 98 of the rod member 94.
The reference surface 172 of the workpiece W is brought into contact with the workpiece abutting plate 70 by loosely fitting the reference hole 166 of the workpiece. Further, the stepped hole portions 168a to 168 of the work W
The positioning pin 144 is fitted into either hole d.

Next, when fluid is supplied to the cylinder chamber 62 in the mounting base 58 from a passage (not shown), the sleeve member 82 is displaced in the direction of arrow A, and the inclined surface 86 formed at the tip of the sleeve member 82 aligns with the inclined surface of the collet 74. The distal end of the collet 74 is pressed radially outward by engagement with the surface 80.

Therefore, the diameter of the collet 74 increases through the slit 78, and the outer circumferential surface of the collet 74 presses the inner circumferential surface of the reference hole 166 of the workpiece W, and as a result, the workpiece positioning mechanism 72 Positioning is performed.

Therefore, when pressure fluid is introduced into the cylinder chamber 90 within the cylinder member 89, the piston member 106 is displaced in the direction of arrow A. Therefore, the clamp arms 112a and 112b that engage with the engagement pin 110 of the plate-shaped portion 109 formed at the tip of the tenth rod 108 are connected to the pin members 114a and 114b.
The pressing surface portions 116a and 116b are exposed to the outside of the large diameter portion 98. Furthermore, the piston member 1
06 in the direction of arrow A, the clamp arm 11
The pressing surface portions 116a and 116b of 2a and 112b press the workpiece W in the direction of arrow B, and as a result, the workpiece W
are the workpiece contact plate 70 and the clamp arm 112a.
, 112b (see FIG. 6a).

That is, the center portion of the workpiece W is accurately positioned by the workpiece positioning mechanism 72 via the reference hole 166, and the workpiece W is firmly fixed to the mounting base 58 by the clamping mechanism 88. Furthermore, the hole positioning mechanism 128
Stepped holes 168a to 168d of the work W through
positioning will be performed.

In this way, after fixing the workpiece W to the jig device 40 and separating the positioning pin 144 from the workpiece W as described later, the first @ feed table 34a is moved and the first tool device 3
6a to the jig device 40 side. In this case, the guide bars 174a, 174b of the first tool device 36a
are fitted into the guide cylindrical portions 56a, 56b of the jig device 40 to accurately guide the first rotary tool 175 provided in the first tool device 36a to the workpiece W. Then, while rotating the first rotary tool 175, for example, the first rotary tool 175 is inserted into the groove 64a of the support portion 50 to perform a predetermined processing on the stepped hole 168a of the workpiece W. After completing the machining of the stepped hole portion 168a, the conveyor table 34a is displaced in the direction of arrow B, and the first tool device 36
a away from the jig device 40.

In this case, a plurality of first rotary tools 175 corresponding to the stepped hole portions 168a to 168d are mounted on the first tool device 36a, such as a gearing head, and the stepped holes are inserted through the respective first rotary tools 175. Holes 168a to 168d
This process performs chamfering and rough machining.

Next, the conveyance table 34b is moved in the direction of arrow B to displace the second tool device 36b toward the jig device 40 side.

The second tool device 36b includes a guide bar 176a.

176b are provided, and each guide bar 176a
.

176b as guide cylindrical parts 52a and 52b of the support part 50.
The second rotary tool 178 is fitted into the inner part to accurately guide the second rotary tool 178 to the workpiece W. Therefore, the second rotary tool 178 is rotated to perform finish cutting on the stepped hole portion 168a after the rough cutting. The second tool device 36b includes the first tool device 36
A plurality of second rotary tools 178 are installed in the same manner as in a, and each of the second rotary tools 178 opens the stepped hole 168a.
Perform finishing cutting from 168d to 168d.

By the way, in this case, the positioning pin 144 is fitted into one of the stepped holes 168a to 168d of the workpiece W to position the stepped holes 168a to 168d. The positioning pin 144 is
The stepped holes 168a to 168 are separated from the holes 168a to 168.
It does not interfere with the processing of d.

That is, after positioning and fixing the workpiece W on the mounting base 58, when the cylinder 154 is driven to displace the piston rod 156 in the direction of the arrow as shown in FIG. 162 is guided by the guide bar 160 and similarly displaced in the direction of the arrow. Therefore, the locking portion 1 formed at one end of the moving plate 162
The positioning pin holder 134 is pressed in the direction of the arrow through the guide pin 1
46 and the guide groove 132, the key 150 is displaced from the workpiece W by a predetermined distance, and the key 150 is guided by the guide plate 148a,
148b. The positioning pin holder 1
34 in the direction of the arrow, the guide pin 146
is deviated counterclockwise (in the direction of arrow C) along the guide groove 132, so that the positioning pin holder 134 rotates counterclockwise.

Therefore, the mounting portion 138 and the positioning pin 144 are integrally offset counterclockwise by a predetermined angle, and the mounting portion 138 and the positioning pin 144 can be moved from any axis of the stepped hole portions 168a to 168d of the workpiece W. It will be a good idea to evacuate. As a result, the first and second tool devices 36a, 3
During machining of the work W by the hole positioning mechanism 128, the respective machining operations are not blocked.

In this way, after finishing the machining of the workpiece W, if fluid is introduced into the cylinder chamber 90 of the cylinder member 89 from the other passage (not shown), the piston member 106 is displaced in the direction of arrow B and moves to the tenth point. The engagement pin 110 fixed to the tip of the pin 108 is similarly displaced in the direction of the top B. Therefore, the clamp arms 112a and 112b swing around the pin members 114a and 114b, and the respective pressing surfaces 116a and 116b are housed within the large diameter portion 98 of the rod member 94, and the clamping action on the work W is released. (See Figure 6).

On the other hand, when the piston portion 84 is displaced in the direction of arrow B via the pressure fluid supplied into the cylinder chamber 62, the inclined surface 86 formed at the tip of the sleeve member 82 moves toward the collet 7.
The diameter of the collet 74 decreases as it moves away from the inclined surface 80 of No. 4. Therefore, the pressing action of the outer circumferential surface of the collet 74 on the inner circumferential surface of the reference hole 166 is released (see FIG. 6).

Therefore, after the workpiece W is gripped by a robot arm or the like and removed from the mount 58, a new workpiece W is positioned and mounted on the mount 58 according to the procedure described above.

In this case, according to the present invention, the clamp mechanism 88 can be made as compact as possible. That is, as mentioned above, in FIG. 6a, distance #H.

By selecting a small value, the clamp arm 112a,
By reducing the angular range in which the engaging pin 112b rotates, the engaging pin 110
, that is, the stroke S of the piston member 106 is shortened. For this reason, the clamp mechanism 88
It becomes possible to suitably reduce the length in the axial direction.

Furthermore, each distance is 1 m so that distance H, < distance H3.
By selecting Hr and Hs, the position of the engaging pin 110 in the unclamped state is set as close to the large diameter portion 98 as possible. If the distance H>distance 'eM Hz, the retaining pin 110 reaches the position shown, for example, by the dashed line in FIG. The length in the axial direction becomes thicker in the direction of arrow B.In the end, the distance HI is shortened, and the distance H,<
By setting the distance fm Hs, the clamp mechanism 88
can be favorably downsized.

On the other hand, the distance is 198IH2#distanceH4. If the distance H1 is longer than the distance H2, the pressing surface portion 116a,
Although the clamping force applied to the workpiece W by 116b increases, the stroke S of the piston member 106 increases, resulting in an increase in the size of the clamping mechanism 88.

Then, the engagement pin 110 and the bottle member 114a (l14
The relationship with b) is distance H3≦distance H4. In this case, if the distance H3 becomes considerably large, the stroke S of the piston member 106 will also become long, and as a result, the clamp mechanism 88 will become large.

Furthermore, according to the present invention, the reference hole 166 of the work W
Since the workpiece W is clamped through the clamping means, the work of attaching and detaching the workpiece W becomes extremely convenient. That is,
When attaching the workpiece W to the jig device 40, the workpiece W is displaced in the direction of arrow B, and the large diameter portion 98 forming the clamping mechanism 88 and the collet 74 forming the workpiece positioning mechanism 72 are inserted into the reference hole 166. After loosely fitting, the work W is fixed to the jig device 40 under the action of the clamp mechanism 88 and the work positioning mechanism 72.

On the other hand, when removing the workpiece W from the jig device 40, it is sufficient to release the action of the clamp mechanism 88 and the workpiece positioning mechanism 72 and displace the workpiece W in the direction of arrow A. The work for attaching and detaching the workpiece W is much easier than in the case where the workpiece W is positioned using the reference hole of the workpiece W and the outer peripheral end of the workpiece W is clamped. Therefore, it is possible to easily automate the work of attaching and detaching the workpiece W. Moreover,
Since the workpiece W is positioned and clamped through the reference hole 166, the single jig device 40 can accommodate workpieces W of various different sizes.

As described above, according to the present invention, the workpiece is clamped using the hole formed in the workpiece, and the clamping mechanism itself is configured to be miniaturized as much as possible. Therefore, the size of the jig device as a whole can be suitably reduced, and moreover, it is possible to suitably handle various workpieces of different sizes. Furthermore, the workpiece attachment work can be simplified, and a highly automated line production process can be achieved, among other advantages.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and changes in design can be made without departing from the gist of the present invention. Of course.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a jig device according to the prior art; FIG. 2 is a side view schematically showing a double-headed machine tool equipped with a jig device incorporating a clamp structure according to the present invention; The figure is a perspective view of the jig device, FIG. 4 is a partially omitted vertical sectional view of the jig device, FIG. 5 is a partially enlarged perspective view of the jig device, and FIGS. 6 a and b are according to the present invention. FIG. 7, which is an explanatory diagram when a workpiece is clamped by the clamp mechanism, is a partially sectional perspective view of the hole positioning mechanism that constitutes the jig device. 40... Jig device 42... Jig stand 48
...Base part 50...Support part 52a
, 52b, 56a, 56b... Cylindrical portion 58.
...Mounting base 64a-64d...Groove portion 7
0... Work contact plate 72... Work positioning mechanism 74... Collet 8
2... Sleeve member 88... Clamp mechanism 89... Cylinder member 94... Rod member 98... Large diameter portion 106... Piston member 108... Rod 110... Engagement bottle 112a , 112b...clamp arm 116
a, 116b... Pressing surface portion 120... Rod 128... Hole positioning mechanism 130... Fixed shaft 1
34...Positioning pin holder 144...Positioning pin

Claims (3)

[Claims] (1) A cylindrical body having a diameter smaller than the diameter of a hole formed in the workpiece, a rod member that engages with an actuator and is disposed in the cylindrical body so as to be able to move forward and backward, and a pin member provided at one end of the rod member. and one or more clamp arms that are engaged with and swingably attached to the cylindrical body via a fulcrum pin, and when clamping the workpiece, a rod member between the workpiece pressing surface of the clamp arm and the fulcrum pin. The distance between the fulcrum pin and the pin member in the axial direction is smaller than the distance between the fulcrum pin and the pin member in the axial direction of the rod member, and the clamp arm is moved by displacing the rod member in one direction under the action of an actuator. The cylindrical body is housed inside the cylindrical body, and the cylindrical body is inserted into the hole of the workpiece, and further, the rod member is displaced in the other direction under the action of the actuator, so that the workpiece pressing surface of the clamp arm is pressed against the workpiece of the cylindrical body. A clamp mechanism configured to press and hold the work while being exposed to the outside. (2) In the clamping mechanism according to claim 1, a groove is formed at one end of the outer periphery of the cylindrical body, oriented in the axial direction, and the workpiece pressing surface of the clamp arm is exposed to the outside through the groove. A clamp mechanism consisting of: (3) In the clamp mechanism according to claim 1, a pressing surface portion for pressing a workpiece is formed at one end of the clamp arm, and a semicircular opening that engages with a pin member is formed at the other end of the clamp arm. A clamp mechanism formed by forming a part.