JP5408984B2 - Clamping device - Google Patents

Description

  The present invention relates to a clamp device, and more particularly to a clamp device that clamps a workpiece by engaging a grip claw of a grip member in a hole of the workpiece and pulling it toward a seating surface.

  In the case of machining over the entire surface of the workpiece, a clamping device that presses the end of the workpiece with a pressing tool from above cannot be employed. Clamp device) is adopted. In this clamping device, a seating surface for seating a workpiece to be clamped is formed on the main body member, and the workpiece is mounted and supported on the seating surface when the workpiece is loaded, and the grip member is inserted into the hole of the workpiece, and the grip member is inserted into the grip member. Insert a clamp rod with a taper shaft and pull the clamp rod toward the seating surface to expand the grip claw with the taper shaft and engage it with the inner peripheral surface of the hole. The workpiece is fixed to the seating surface by pulling it toward the seating surface.

Patent Documents 1 and 2 disclose the clamping device as described above.
In particular, in the clamping device described in Patent Document 1, in order to cope with the variation in the position of the hole of the workpiece, a grip member and a clamp rod having a tapered shaft portion are configured to be movable in a direction orthogonal to the axis, Even when the position of the hole is slightly deviated from the original normal position, it can be clamped securely.

The clamping device is provided with a seating surface on which the workpiece is seated for positioning in the axial direction when the workpiece is fixed. The workpiece is attracted to the seating surface side by the grip member and the clamp rod, and the workpiece is in close contact with the seating surface, so that the workpiece can be positioned in the axial direction with respect to the clamp device.
Japanese Patent No. 355010 German Patent No. 4020981

  By the way, this clamping device has a structure in which a plurality of grip claws provided in the grip portion of the grip member are bitten into the inner peripheral surface of the workpiece hole and gripped, and the grip portion is closely attached to the hole of the workpiece. Since it is not the structure to fit, parts other than the grip claw of a grip member are formed in the diameter smaller than the hole of a workpiece | work. For this reason, this clamping device can be positioned in the axial direction of the grip member and clamp rod by bringing the workpiece into close contact with the seating surface, but has a positioning function in a direction perpendicular to the axial center. Not. Therefore, the workpiece cannot be positioned with high accuracy (accuracy of about 10 μm) in the direction perpendicular to the axis with respect to the clamp body of the clamp device.

  For example, in a state where a plurality of holes formed in the flange portion of the workpiece are clamped by a plurality of clamping devices, the top surface of the flange portion is machined, and then the spigot fitting portion or the spigot fitting hole is formed from the top surface side of the flange portion. When the workpiece is machined, the positioning accuracy when the workpiece is clamped by a plurality of clamping devices is low, and therefore the positional accuracy of the spigot fitting portion or the spigot fitting hole with respect to the flange portion cannot be increased.

  The objective of this invention is providing the clamp apparatus which can position a workpiece | work with high precision with respect to a clamp apparatus.

According to a first aspect of the present invention, there is provided a gripping device capable of gripping an inner peripheral surface of a hole in a state where the diameter is expanded after being inserted into a hole having a cylindrical inner peripheral surface of a workpiece which is a clamp target, and the grip member A clamp device having a clamp rod having a taper shaft portion fitted therein and a fluid pressure cylinder capable of driving the grip member and the clamp rod forward and backward in the axial direction, wherein the grip member, the clamp rod and the fluid pressure are A positioning fitting formed integrally with the clamp body on an outer peripheral side portion of the grip member and the clamp rod, of a clamp body provided with a cylinder, and a workpiece side end of the clamp body; And a positioning fitting portion for positioning the workpiece by fitting into a positioning fitting recess formed in the workpiece.

  According to a second aspect of the present invention, the clamp device according to the first aspect of the present invention is parallel to a direction orthogonal to the clamp rod on the outer peripheral side portion of the base end portion of the clamp body opposite to the workpiece of the positioning fitting portion. It is characterized in that it is provided with a seating surface that can be formed to seat a workpiece.

  According to a third aspect of the present invention, in the invention of the first or second aspect, the positioning fitting portion is formed in an annular shape having a circular outer periphery.

  A clamp device according to a fourth aspect is characterized in that, in the invention according to any one of the first to third aspects, the positioning fitting concave portion is formed concentrically with the hole of the workpiece.

  According to a clamp device of a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the hole of the workpiece is formed as a tapered hole that gradually decreases in diameter toward the clamp body, and the grip member is formed of the tapered hole. It is characterized by having a grip part which can be closely engaged with the grip part and has a tapered outer peripheral surface which gradually decreases in diameter toward the clamp body.

  According to a sixth aspect of the present invention, there is provided the clamping apparatus according to the third aspect, wherein the positioning fitting portion has the same diameter as the outer peripheral shape and is formed at a position facing each other across the axis. And a pair of small diameter portions having a smaller diameter than the partial cylindrical portion formed in a portion other than the pair of partial cylindrical portions.

According to the invention of claim 1, of the workpiece side end portion of the clamp body, a positioning fitting portion formed integrally with the clamp body on the outer peripheral side portion of the grip member and the clamp rod, A positioning fitting portion for positioning the workpiece by fitting into the positioning fitting recess formed in the workpiece, so that when the workpiece is fixed to the clamping device, the clamping device positioning fitting The portion can be fitted into the positioning recess for positioning the workpiece, so that the workpiece can be positioned with high accuracy in the direction orthogonal to the grip member of the clamp device and the axis of the clamp rod, and the processing accuracy can be improved. .

  According to invention of Claim 2, it is formed in the outer peripheral side part of the base end part on the opposite side to the workpiece | work of the said positioning fitting part among the said clamp main bodies in parallel with the direction orthogonal to a clamp rod. Since the seating surface that can be seated is provided, when the work is fixed to the clamping device, the work can be seated in close contact with the seating surface, and the work can be positioned with high accuracy in the axial direction. Can be improved.

  According to the invention of claim 3, since the positioning fitting portion is formed in an annular shape having a circular outer peripheral shape, the positioning fitting portion can be formed easily and inexpensively.

  According to the invention of claim 4, since the positioning fitting recess is formed concentrically with the hole of the workpiece, the positioning fitting recess can be easily and inexpensively formed.

  According to invention of Claim 5, the hole of the said workpiece | work is formed in the taper hole which becomes small diameter gradually toward the said clamp main body, The said grip member is a grip part which can be engaged in the said taper hole closely. And since it has a grip part which has a taper outer peripheral surface which becomes small diameter gradually toward the said clamp main body, grip performance can be improved.

  According to the invention of claim 6, the positioning fitting portion has a pair of partial cylindrical portions having the same diameter as the outer peripheral shape and formed at positions facing each other across the axis, and the pair Since there is a pair of small diameter portions having a smaller diameter than the partial cylindrical portion formed in the portion other than the partial cylindrical portion, when the workpiece is clamped by a plurality of clamping devices, the plurality of positioning fitting recesses on the workpiece side Even if there is an error in the distance between them, the error can be absorbed through the pair of small diameter portions.

  Hereinafter, the best mode for carrying out the present invention will be described based on examples.

  The clamping devices C and CA of the present invention are each mounted on a rectangular base plate B, and the workpiece is pulled toward the seating surface 18 by engaging the grip claw 24 of the grip member 2 in the hole H of the workpiece W. W is clamped to the base plate B. First, the clamp device C will be described, and then the clamp device CA will be described.

First, the clamp device C will be described.
As shown in FIGS. 1 to 3, the clamp device C can drive the clamp body 1, the grip member 2, the clamp rod 3, and the grip member 2 and the clamp rod 3 in the axial direction (vertical direction). A hydraulic cylinder 4 (fluid pressure cylinder) and an annular pressure receiving member 5 included in the hydraulic cylinder 4 are provided. The clamp body 1 (clamp body) includes an upper body member 11, a lower body member 12, and a base body member 13. The base body member 13 is formed integrally with the base plate B. The grip member 2, the clamp rod 3, and the hydraulic cylinder 4 are attached to the clamp body 1.

  The upper main body member 11 is substantially oval in plan view, and the upper main body member 11 is fixed to the base main body member 13 (base plate B) with four bolts 14 inserted into four bolt holes. The lower main body member 12 is a cylindrical member that forms a cylinder hole 41, and the upper end portion of the lower main body member 12 is fitted into the concave portion 15 on the lower surface side of the upper main body member 11, and the upper main body member 11 is secured by four bolts 16. It is fixed to.

This clamping device C is a positioning fitting portion 19 formed integrally with the clamp body 1 on the outer peripheral side portion of the grip member 2 and the clamp rod 3 in the workpiece W side end portion of the clamp body 1. And a positioning fitting portion 19 for positioning the workpiece W by fitting into the positioning fitting recess 20 formed in the workpiece W. The positioning fitting portion 19 (hereinafter, referred to as the fitting portion 19) is formed in an annular shape having a circular outer peripheral shape, and is integrally formed on the upper end portion of the upper body member 11. The positioning fitting recess 20 (hereinafter referred to as the fitting recess 20) is formed to have a diameter larger than the diameter of the hole H of the workpiece W and concentric with the hole H of the workpiece W. The fitting recess 20 has a circular cross-sectional shape in a plane orthogonal to the axis of the hole H.

  Seating which is formed in parallel with the direction orthogonal to the clamp rod 3 on the outer peripheral side portion of the base end portion on the opposite side to the workpiece W of the positioning fitting portion 19 in the clamp body 1 and can seat the workpiece W. A surface 18 is provided. Since the seating surface 18 is formed in an annular shape so as to surround the grip member 2 and is formed on the upper main body member 11, the workpiece W can be seated on the seating surface 18 to be in a clamped state. The upper surface of the upper body member 11 is formed as a partial conical surface having a gentle inclination angle.

  As shown in FIGS. 1 to 3, the grip member 2 is disposed so as to vertically penetrate the opening hole 17 in the central portion of the upper body member 11. The substantially annular grip member 2 is capable of gripping the inner peripheral surface of the hole H in a state where the diameter is increased after being inserted into the hole H of the workpiece W which is a clamp target. The grip member 2 includes a rod insertion hole 21, a middle tube portion 23 formed at the middle step portion, a grip claw portion 24 formed above the middle step tube portion 23, and a grip claw portion with respect to the middle step tube portion 23. 24 and a base end flange portion 26 formed on the opposite side.

The grip member 2 includes four grip division bodies 2b in which a middle tube portion 23, a grip claw portion 24, and a base end collar portion 26 are divided into four equal parts in the circumferential direction by slits (not shown). The grip member 2 is formed of a metal member, and the grip member 2 has three steps that make it easy to grip the cylindrical inner peripheral surface of the hole H of the workpiece W on the outer peripheral surface of the grip claw portion 24 of each grip divided body 2b. Teeth 24a are formed. A rod insertion hole 21 through which the clamp rod 3 is inserted is formed in the grip member 2, and a portion corresponding to the grip claw portion of the rod hole 21 is a taper in which the taper shaft portion 31 of the clamp rod 3 is closely engaged. It is formed in the hole 21a.

  As shown in FIGS. 1 to 3, a scraper 28 made of an elastic material such as rubber or synthetic resin is attached to the opening hole 17 of the upper main body member 11 so as to be in sliding contact with the middle tube portion 23 of the grip member 2. An O-ring 29 for urging the divided grip claw portion 24 in the diameter reducing direction is attached to the outer peripheral portion of the grip member 2. The base end flange portion 26 of the grip member 2 is accommodated in the circular recess 6 of the upper body member 11 and is sandwiched between the upper wall portion of the circular recess 6 and the horizontal plate portion 62 of the annular pressure receiving member 5. The grip member 2 can move up and down integrally with the annular pressure receiving member 5, and can move in the horizontal direction perpendicular to the axial center of the hydraulic cylinder 4 through elastic deformation of the annular gap 7 of the circular recess 6 and the scraper 28. It is attached to.

  The clamp rod 3 includes a tapered shaft portion 31 that is fitted and engaged with the grip member 2, a small-diameter rod portion 32 that continues to the lower end of the tapered shaft portion 31, and a large-diameter rod portion 33 that continues to the lower end of the small-diameter rod portion 32. And a large-diameter flange 34 connected to the lower end of the large-diameter rod portion 33 is integrally formed. The tapered shaft portion 31 and the small diameter rod portion 32 are inserted into the rod hole 21 of the grip member 2. The taper shaft portion 31 is formed at the upper end portion of the clamp rod 3 so as to increase in diameter toward the upper side, and the taper shaft portion 31 is fitted and engaged with the taper hole portion 21 a of the grip member 2.

  As shown in FIGS. 1 to 3, the hydraulic cylinder 4 is for driving the grip member 2 and the clamp rod 3 forward and backward in the axial direction. The hydraulic cylinder 4 includes an upright cylinder hole 41 formed by the lower main body member 12 and the base main body member 13, a piston member 42 mounted in the cylinder hole 41, and the piston member 42 integrated with the piston. A cylindrical piston rod 44 extending upward from the portion 43, a clamping oil chamber 45 above the piston portion 43, an unclamping oil chamber 46 below the piston portion 43, and the annular pressure receiving member 5 are provided.

  The bottom surface of the cylinder hole 41 is closed by the base body member 13, and a stop ring 47 that restricts the downward movement of the piston member 42 is attached to the annular groove near the lower end of the cylinder hole 41. The piston member 42 is received by the stop ring 47 and becomes the lower limit position. A central hole is formed in the piston member 42, and this central hole is composed of an upper small diameter hole 48 formed in the cylindrical piston rod 44, an intermediate diameter hole 49 in the middle step portion, and a lower large diameter hole 50. Yes. A sealing member 51 is attached to the large-diameter hole 50 and is prevented from coming off by a stop ring 52a.

  The large-diameter rod portion 33 of the clamp rod 3 is located in the small-diameter hole 48, and the large-diameter collar portion 34 is located in the medium-diameter hole 49. An annular gap 48a of about 2 mm is formed between the large diameter rod portion 33 and the inner peripheral surface of the small diameter hole 48, and a thick O-ring 52 (elastic ring member) is attached to the annular groove on the outer periphery of the large diameter rod portion 33. The O-ring 52 is mounted between the large-diameter rod portion 33 and the cylindrical piston rod 44 in a slightly compressed state.

  The thickness of the large diameter flange 34 is substantially equal to the thickness of the medium diameter hole 49. A slight gap is formed between the outer peripheral surface of the large diameter flange 34 and the inner peripheral surface of the medium diameter hole 49. Therefore, the clamp rod 3 moves up and down integrally with the piston member 42, but is movable relative to the piston member 42 in the horizontal direction perpendicular to the axis. The grip member 2 can move in the horizontal direction orthogonal to the axis center together with the clamp rod 3. Here, the scraper 28 and the O-ring 52 elastically bias the grip member 2 and the clamp rod 3 so that the axes of the grip member 2 and the clamp rod 3 coincide with the axis of the hydraulic cylinder 4.

  As shown in FIGS. 1 to 3, the annular pressure receiving member 5 includes a pressure receiving cylinder portion 61 and a horizontal plate portion 62 that is continuous with the upper end of the pressure receiving cylinder portion 61. Two proximal end flanges 26 are placed to support the proximal end surface of the grip member 2. The large-diameter rod portion 33 of the clamp rod 3 is inserted into the circular hole 63 in the center portion of the horizontal plate portion 62 in a loosely fitting manner, and the outer peripheral portion of the horizontal plate portion 62 is slightly more than the pressure-receiving cylinder portion 61. A large-diameter locking rod 62a is formed. The lower main body member 12 is formed with an upper cylinder hole 64 having a smaller diameter than the cylinder hole 41 connected to the upper end of the cylinder hole 41.

  The upper body member 11 is formed with a receiving hole 65 that is continuous with the upper end of the upper cylinder hole 64. The thickness of the accommodation hole 65 is, for example, about 1.2 to 2.0 mm larger than the thickness of the horizontal plate portion 62. The pressure receiving cylinder portion 61 of the annular pressure receiving member 5 is mounted in an annular hole between the inner peripheral surface of the upper cylinder hole 64 and the cylindrical piston rod 44 in an oil-tight manner and slidable in the vertical direction. The housing hole 65 is slidably mounted in the vertical direction. A plurality of seal members (not shown) are provided to prevent hydraulic oil leakage from the oil chamber.

  The lower end of the pressure receiving cylinder portion 61 of the annular pressure receiving member 5 faces the clamping hydraulic chamber 45 and receives the hydraulic pressure. The clamping oil chamber 45 is connected to a hydraulic pressure supply source via oil passages 67 and 68, and a hydraulic pressure detection sensor (not shown) for detecting the hydraulic pressure of the oil passages 67 and 68 is also provided. The unclamping oil chamber 46 is connected to a hydraulic pressure supply source via an oil passage 71, and a hydraulic pressure detection sensor (not shown) for detecting the oil pressure of the oil passage 71 is also provided. The annular pressure receiving member 5 is predetermined in the axial direction over a first position where the grip member 2 is moved outward (upward) and a second position where the grip member 2 is retracted (lowered). The stroke can be moved.

As shown in FIGS. 1 to 3, a seating sensor (not shown) is provided for detecting that the lower surface of the workpiece W is in close contact with the seating surface 18 in a state where the workpiece W is clamped. The seating sensor includes a pressurized air ejection hole (not shown) opened in the seating surface 18 and an air passage (not shown) formed in the upper main body member 11 so as to communicate with the pressurized air ejection hole. A pressurized air supply source that supplies pressurized air to the air passage, and a pressure switch that detects that the pressure of the pressurized air in the air passage has been increased to a predetermined value or more.
An air passage (not shown) for supplying pressurized air to the opening hole 17 is formed in the upper body member 11 for air blowing. The air supplied to the opening hole 17 flows upward from the slit of the grip member 2, blows air on the seating surface 18, and excess air flows to the outside.

Next, the clamp device CA will be described.
The clamp device CA is applied to clamp a workpiece in cooperation with the clamp device C, and the clamp device CA is disposed at a position away from the clamp device C by a predetermined distance. It is applied to clamp in a state where one end side portion of the workpiece is positioned by the clamp device C, and to position and clamp the other end side portion of the workpiece by the clamp device CA. Since the configuration other than the structure of the positioning fitting portion 19 is the same as that of the clamp device C, the same components are denoted by the same reference numerals and description thereof is omitted, and only different configurations will be described.

  As shown in FIGS. 1, 2, and 4, the positioning fitting portion 19 </ b> A of the clamp device CA has the same diameter as the fitting portion 19 and is formed at a position facing the shaft center. It has a pair of partial cylindrical portions 19a and a pair of small diameter portions 19b having a smaller diameter than the partial cylindrical portions 19a formed in portions other than the pair of partial cylindrical portions 19a. The pair of small diameter portions 19b is composed of four chamfered portions 19c formed with an axis therebetween. In a state where the workpiece W is clamped, a slight gap 20a is formed between the chamfered portion 19c and the outer peripheral surface of the positioning fitting concave portion 20.

The operation and effect of the clamping devices C and CA will be described above.
When the workpiece W is fixed by the clamping devices C and CA, first, substantially the same hydraulic pressure is supplied to the clamping oil chamber 45 and the unclamping oil chamber 46. Then, since the pressure receiving area of the unclamping oil chamber 46 is larger than the pressure receiving area of the clamping oil chamber 45 in the piston member 42, the piston member 42 is raised to the upper limit position and stopped as shown in FIG. It becomes. The annular pressure receiving member 5 holds the upper limit position to receive the hydraulic pressure of the clamping oil chamber 45, and the grip member 2 also holds the upper limit position.

  In this state, the workpiece W is loaded, and as shown in FIGS. 2 and 3, the grip members 2 and the clamp rods 3 of the clamping devices C and CA are inserted into the pair of holes H of the workpiece W, respectively. The workpiece W is seated on both seating surfaces 18 with the fitting portions 19 and 19A fitted in a pair of fitting recesses 20 and 20 formed concentrically with the pair of holes H, respectively. At this time, even if there is an error in the distance between the centers of the fitting recesses 20 and 20 due to a manufacturing error of the workpiece W, this error is absorbed through the pair of small diameter portions 19b formed on the clamping device CA side. Can do.

  Next, the hydraulic pressure of the unclamping oil chamber 46 is switched to a predetermined hydraulic pressure lower than the hydraulic pressure of the clamping oil chamber 45, and a predetermined hydraulic pressure that is somewhat strong downward is applied to the piston member 42. Then, the annular pressure receiving member 5 that receives the hydraulic pressure of the clamping oil chamber 45 holds the upper limit position as described above, and the grip member 2 also holds the upper limit position. However, the piston member 42 receives downward oil pressure. As a result, the piston member 42 is driven downward, so that the clamp rod 3 moves downward relative to the grip member 2.

  As a result, the grip claw portion 24 of the grip member 2 is driven to expand in diameter by the taper shaft portion 31 of the clamp rod 3, and the inner peripheral surface of the hole H of the workpiece W is gripped and brought into an engaged state. In this state, if the hydraulic pressure in the unclamping oil chamber 46 is reduced to the drain pressure, a large downward hydraulic pressure acts on the piston member 42, and the grip member 2 and the clamp rod 3 are not relatively movable. The piston member 42, the grip member 2, the clamp rod 3, and the annular pressure receiving member 5 are integrally driven downward, and the workpiece W is brought into close contact with the seating surface 18 and stopped in a clamped state that is strongly attracted downward. To do.

  The fitting portions 19 and 19A of the clamping devices C and CA are fitted into the fitting recesses 20 and 20 of the workpiece W, respectively, and the workpiece W is positioned in a direction perpendicular to the axis of the clamping devices C and CA. Since the bottom surface of the workpiece W is brought into close contact with the seating surface 18 and positioning is performed in the axial direction, the workpiece W can be positioned with respect to the base plate B with high accuracy. Therefore, the grip member 2 and the clamp rod 3 can be positioned with high accuracy in the axial direction, and the processing accuracy can be improved. Here, since the pair of partial arc portions 19a of the clamp device CA are disposed on both sides of the line connecting the axes A and AA of the clamp devices C and CA, the pair of fitting portions 19A of the clamp device CA is paired. The partial arc portion 19a restricts the movement of the clamping device C in the rotational direction about the axis A, and the gap 20a formed between the small diameter portion 19b and the fitting recess 20 fits the workpiece W. Clamping can be ensured by the clamping devices C and CA while absorbing manufacturing errors in the dimensions between the joint recesses 20 and 20.

  Since the workpiece W is clamped by the plurality of clamping devices C and CA, when the position of the center of the hole H of the workpiece W is slightly shifted due to the manufacturing error of each workpiece W, the clamp rod 3 and the grip member 2 are moved. When inserted into the hole H and clamped, the axis of the clamp rod 3 and the grip member 2 is displaced from the axis of the hydraulic cylinder 4 through elastic deformation of the scraper 28 and the O-ring 52 to absorb the error. can do.

  When the clamping devices C and CA are returned to the unclamped state after machining the workpiece W, the axial centers of the clamp rod 3 and the grip member 2 are made to be the axial center of the hydraulic cylinder 4 by the elastic force of the scraper 28 and the O-ring 52. Automatically return to match. In this case, since the elastic force is applied to the clamp rod 3 at two positions, the clamp rod 3 is returned, the clamp rod 3 can be returned smoothly without play. Therefore, it is not necessary to manually perform a return operation for making the two axes coincide with each other in the unclamped state, so that the work efficiency of the work clamping operation can be increased. Moreover, the O-ring 52 reliably prevents foreign matter such as chips from entering the sliding portion between the large-diameter flange 34 of the clamp rod 3 and the medium-diameter hole 49 of the cylindrical piston rod 44. Smooth sliding movement in the direction orthogonal to the axial direction of 3 can be reliably ensured.

  By the way, when exchanging the grip member 2, it can be performed as follows. First, the upper main body member 11 bolted to the lower main body member 12 and the base main body member 13 is removed. In this case, the upper main body member 11 is moved upward and removed. When the upper body member 11 is removed, the grip member 2 is completely divided into four parts, so that each part of the grip member can be easily removed without causing interference with the clamp rod 3. When the new grip member 2 is mounted, the reverse operation can be performed.

  The clamp devices CB and CC according to the second embodiment will be described. The clamp devices CB and CC are the same as the clamp devices C and CA of the first embodiment except for the structure of the grip claw portion 24B of the grip member 2 and the structure of the hole HB of the workpiece W. The same reference numerals are assigned to the main constituent elements, the description thereof is omitted, and only different configurations will be described.

  As shown in FIGS. 5 to 7, in the clamping devices CB and CC, the hole HB of the workpiece W is formed as a tapered hole that gradually decreases in diameter toward the clamp body 1. The cross-sectional shape in a plane orthogonal to the axis of the hole HB is a circle. The grip member 24 </ b> B is a grip portion 24 </ b> B that can be brought into close contact with the tapered hole, and has a grip portion 24 </ b> B having a tapered outer peripheral surface that gradually decreases in diameter toward the clamp body 1. However, the minimum diameter of the hole HB is formed such that the grip member 2 and the clamp rod 3 in a reduced diameter state can be inserted. Since the hole HB is formed in a tapered hole that gradually decreases in diameter toward the main body member 1, grip performance can be improved.

Next, a modified example in which the above embodiment is partially modified will be described.
1] Like the clamping device of the first embodiment, the workpiece is not necessarily clamped by two sets of clamping devices, but may be clamped by one set of clamping devices, or may be clamped by three or more sets of clamping devices. May be. The holes H and HB of the workpiece W may be bag holes or through holes.

2] One or a plurality of circumferentially shallow concave grooves may be formed on the inner peripheral surfaces of the holes H and HB of the workpiece W so as to facilitate engagement with the grip claws of the grip member.
3] In addition, those skilled in the art can implement the present invention in a form in which various modifications cannot be made without departing from the gist of the present invention, and the present invention includes those modified forms.

It is a top view of two sets of clamp devices concerning Example 1 of the present invention. It is the II-II sectional view taken on the line of FIG. It is sectional drawing of the clamp apparatus of the left side of FIG. It is sectional drawing of the clamp apparatus of the right side of FIG. FIG. 3 is a diagram corresponding to FIG. 2 according to the second embodiment. FIG. 3 is a diagram corresponding to FIG. 3 according to the second embodiment. FIG. 6 is a diagram corresponding to FIG. 4 according to the second embodiment.

W Work H, HB Hole C, CA, CB, CC Clamp device 1 Main body member 2 Grip member 3 Clamp rod 4 Hydraulic cylinder 5 Annular pressure receiving member 18 Seating surface 19, 19A Positioning fitting portion 20 Positioning fitting recess 24, 24B Grip part

Claims (6)

A grip member capable of gripping the inner peripheral surface of the hole in a state where the diameter is expanded after being inserted into a hole having a cylindrical inner peripheral surface of a workpiece to be clamped, and a tapered shaft which is fitted and engaged with the grip member. A clamp rod having a clamp rod, and a fluid pressure cylinder capable of driving the grip member and the clamp rod back and forth in the axial direction.
A clamp body to which the grip member, the clamp rod, and the fluid pressure cylinder are attached;
A positioning fitting formed integrally with the clamp main body on the outer peripheral side portion of the grip member and the clamp rod among the workpiece side end portions of the clamp main body, the positioning fitting formed on the workpiece A clamping device comprising: a positioning fitting portion for positioning a workpiece by fitting in a fitting recess.   A seating surface formed parallel to a direction orthogonal to the clamp rod and seated on the outer peripheral side portion of the base end portion on the opposite side to the workpiece of the positioning fitting portion of the clamp body is provided. The clamping device according to claim 1, wherein:   The clamping device according to claim 1 or 2, wherein the positioning fitting portion is formed in an annular shape having a circular outer periphery.   The clamping device according to claim 1, wherein the positioning fitting recess is formed concentrically with the hole of the workpiece. The hole of the workpiece is formed into a tapered hole that gradually decreases in diameter toward the clamp body,
2. The grip member according to claim 1, wherein the grip member is a grip portion that can be brought into close contact with the tapered hole and has a tapered outer peripheral surface that gradually decreases in diameter toward the clamp body. The clamp apparatus in any one of -4.   The positioning fitting portion has a pair of partial cylindrical portions that have the same diameter as the outer peripheral shape and are opposed to each other across the axis, and a portion other than the pair of partial cylindrical portions. The clamping device according to claim 3, further comprising a pair of small-diameter portions having a smaller diameter than the formed partial cylindrical portion.