JP2009214293A5 - - Google Patents

Description

Clamping device

  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 surely clamped.

  By the way, in general, a seating sensor is often provided on the seating surface of the clamping device in order to detect whether or not the workpiece has been properly seated on the intended seating surface when the workpiece is fixed by the clamping device. The seating sensor includes a pressurized air ejection hole that opens to a seating surface, an air supply path that supplies pressurized air to the pressurized air ejection hole, and an air pressure in the air supply path increases to a predetermined pressure or more. It is comprised with the pressure switch etc. which detect this.

Japanese Patent No. 355010 German Patent No. 4020981

  When the seating surface and the seating sensor for receiving the workpiece are provided in the clamping device, when the workpiece is inserted and seated on the seating surface, the pressurized air ejection hole of the seating sensor is closed by the wall surface of the workpiece, In spite of the fact that the clamping operation to be fixed has not been completed, the seating sensor detects the seating of the workpiece, and there is a problem that it is erroneously determined that the workpiece clamping operation has been completed.

  Furthermore, in the clamping device of Patent Document 1, in order to enable clamping even when the position of the hole of the workpiece is slightly deviated from the normal position, the grip member and the clamp rod having the tapered shaft portion are arranged in a direction perpendicular to the axis. It is configured to be movable. However, a mechanism is provided to return the grip member and clamp rod to their normal original position (center position) when the grip member and clamp rod move in the direction perpendicular to the axis to perform clamping and then become unclamped. Therefore, it is necessary to manually return the grip member and clamp rod to the original position. If the return operation is omitted, it is difficult to insert the grip member and clamp rod into the workpiece hole. As a result, the work efficiency for fixing the work is reduced.

  On the other hand, as described above, when clamping the workpiece with the hole clamp device, the grip member and the clamp rod are inserted into the hole of the workpiece, and the grip claw of the grip member is expanded at the time of clamping. The diameter of the nail is reduced by an urging force such as an O-ring. However, when the grip claw is engaged with the inner surface of the hole of the workpiece, there is a problem that the diameter of the grip claw cannot be reliably reduced only by the urging force of the O-ring.

  An object of the present invention is to provide a clamping device in which a workpiece is supported by a workpiece mounting surface formed on a grip member immediately after the workpiece is loaded and is seated on a seating surface during clamping.

The clamp device according to claim 1 is an annular grip member that can be inserted into a hole of a workpiece and grip an inner peripheral surface of the hole, a clamp rod having a tapered shaft portion that is fitted and engaged with the grip member, In the clamping device having a fluid pressure cylinder capable of driving the grip member and the clamp rod to retreat in the axial direction, an upper body member and a lower body member to which the grip member, the clamp rod, and the fluid pressure cylinder are attached, A seating surface formed on the upper body member for seating a workpiece, and a workpiece mounting surface formed on the grip member so as to be able to receive the workpiece at a position closer to the advancing side than the seating surface when the grip member is in the advanced position. The fluid pressure cylinder includes a cylinder hole, and a piston member mounted in the cylinder hole and connected to the clamp rod; And a said fluid clamp formed in the cylinder bore chamber and the unclamping fluid chamber, said gripping member and the clamp rod which is movable integrally with the direction perpendicular to the axis of the fluid pressure cylinder It is a feature.
In the clamping device according to the first aspect, when the workpiece to be clamped is put in the unclamped state, the workpiece is supported by the workpiece mounting surface of the grip member at the advanced position. When the gripping member and the clamp rod are driven in the direction in which the workpiece is seated by the fluid pressure cylinder from that state, the gripping member moves backward to be fixed in a state where the workpiece is seated on the seating surface.
According to a second aspect of the present invention, there is provided the clamping device according to the first aspect of the invention, wherein the clamp rod is orthogonal to the axial center on the outer periphery of the clamp rod on the retracting side of the grip member. The clamp rod is mounted between the annular portion and the clamp rod so that the axial center of the grip member and the clamp rod is aligned with the axial center of the fluid pressure cylinder. An elastic ring member that is elastically biased in a direction orthogonal to the axis is provided.

According to a third aspect of the present invention, there is provided a clamping device according to the first aspect of the present invention, wherein a pressurized air ejection hole for a seating sensor opened in the seating surface is provided. It is detected that the work is seated and fixed on the seating surface.

According to a fourth aspect of the present invention, in the clamp device according to the first or second aspect, the grip member includes an annular flange that forms the workpiece mounting surface, a grip claw that extends outward from the annular flange, and the annular flange. And a base end collar portion formed on the opposite side of the grip claw portion, and the grip member is formed of a plurality of grip division bodies divided at a plurality of positions at equal intervals in the circumferential direction.

According to a fifth aspect of the present invention, in the invention of the fourth aspect , the clamp device is in sliding contact with the outer peripheral surface of the annular flange of the grip member so that the axis of the grip member and the clamp rod coincide with the axis of the fluid pressure cylinder. As described above, a scraper made of an elastic material for elastically urging the grip member in a direction orthogonal to the axis is provided.

A clamp device according to a sixth aspect is the invention according to the fourth aspect , wherein the fluid pressure cylinder is configured to drive the clamp rod in the retracted direction when clamping and to drive the clamp rod in the advanced direction when releasing the clamp. It is characterized in that a diameter reducing mechanism is provided for gathering the plurality of grip divisions of the grip member in a reduced diameter state close to the clamp rod when the clamp is released.

According to a seventh aspect of the present invention, in the invention of the sixth aspect , the diameter reducing mechanism includes a tapered surface formed at the proximal end portion of the grip member so as to decrease in diameter downward, and the tapered surface is engaged with the tapered surface from below. And a taper engaging portion formed on the clamp rod so as to be able to be combined and having a larger diameter toward the upper side.

  According to the first aspect of the present invention, an upper body member, a lower body member, and a seating surface formed on the upper body member are provided in a clamp device having a grip member, a clamp rod, and a fluid pressure cylinder. The workpiece mounting surface is formed on the grip member so that the workpiece can be received at a position closer to the advance side than the seating surface when the is in the advanced position. Therefore, the workpiece is supported by the workpiece mounting surface after the workpiece to be clamped is inserted and before clamping. The workpiece can be seated on the seating surface when the workpiece is clamped and fixed.

And since the grip member and the clamp rod are formed so as to be integrally movable in the direction orthogonal to the axis of the fluid pressure cylinder, even when the position of the hole is slightly shifted due to the manufacturing error of the hole of the workpiece, The grip member and the clamp rod can be clamped through movement in a direction orthogonal to the axis.

According to the second aspect of the present invention, an annular portion that does not move in the direction orthogonal to the axis is provided on the outer periphery of the clamp rod on the retracting side of the grip member. The clamp rod is mounted between the annular portion and the clamp rod so that the axis of the grip member and the clamp rod is aligned with the axis of the fluid pressure cylinder. Since the elastic ring member that elastically urges is provided, when the unclamped state is established, the elastic ring member is elastically urged so that the axis of the grip member and the clamp rod coincide with the axis of the fluid pressure cylinder, The grip member and clamp rod automatically return to their original positions where the two axes coincide. Therefore, it is not necessary to perform a complicated operation of returning the grip member and the clamp rod to the original positions by manual operation.
Also, it is possible to realize an elastic biasing means having a simple configuration that elastically biases the grip member and the clamp rod so that the axes of the grip member and the clamp rod coincide with the axis of the fluid pressure cylinder.

According to the invention of claim 3, since the pressurized air ejection hole for the seating sensor opened in the seating surface is provided, when the workpiece is clamped and fixed, the workpiece is seated on the seating surface, and the normal clamping state is obtained. When fixed, it can be reliably detected that the work is seated on the seating surface and fixed.

According to a fourth aspect of the present invention, the grip member includes an annular flange portion that forms a workpiece mounting surface, a grip claw portion that extends outward from the annular flange portion, and is opposite to the grip claw portion with respect to the annular flange portion. The grip member is composed of a plurality of grip divided bodies that are divided at a plurality of positions at equal intervals in the circumferential direction, so that the grip member can be easily expanded in diameter during clamping. At the time of release, the grip member is easily reduced in diameter.

According to the invention of claim 5, the grip member is slidably contacted with the outer peripheral surface of the annular flange portion of the grip member so that the axis of the grip member and the clamp rod are aligned with the axis of the fluid pressure cylinder. Since the scraper made of an elastic material that elastically urges in the direction orthogonal to the shaft center is provided, the scraper can also be used as the elastic urging means, and an elastic urging means having a simple configuration can be realized.

According to the invention of claim 6, the fluid pressure cylinder is configured to drive the clamp rod in the retracting direction at the time of clamping and to drive the clamp rod in the advancing direction at the time of releasing the clamp. Since the diameter reducing mechanism for collecting the grip divided bodies in a reduced diameter state close to the clamp rod is provided, the plurality of grip divided bodies can be reliably reduced in diameter when the clamp is released.

According to a seventh aspect of the present invention, the diameter reducing mechanism is formed on the clamp rod so as to be able to engage with the tapered surface from below, and a tapered surface formed so as to decrease in diameter toward the base end portion of the grip member. And a taper engaging portion whose diameter is increased toward the upper side, so that the force of reducing the diameter from the clamp rod to the proximal end portion of the grip member by the guide action of the tapered surface of the grip member and the taper engaging portion of the clamp rod. And the plurality of grip divisions can be reliably reduced in diameter when the clamp is released.

It is a top view of the clamp device concerning the example of the present invention. It is a longitudinal cross-sectional view of the clamp apparatus (work input state) of FIG. It is a fragmentary longitudinal cross-sectional view of the clamp apparatus (clamp state) of FIG. It is a fragmentary longitudinal cross-sectional view of the clamp apparatus of FIG. It is a fragmentary longitudinal cross-sectional view of the clamp apparatus (clamp failure state) of FIG. It is a principal part expansion longitudinal cross-sectional view of the clamp defect detection mechanism of the clamp apparatus of FIG. FIG. 6 is an enlarged vertical cross-sectional view of a main part in a state where the clamping failure detection mechanism of the clamping device of FIG. It is a figure showing the relationship between the grip operation | movement of the workpiece | work W, and a clamp operation | movement. FIG. 6 is a diagram corresponding to FIG. 4 according to the second embodiment. FIG. 4 is a diagram corresponding to FIG. 4 according to the third embodiment. FIG. 6 is a view corresponding to FIG. 4 according to the fourth embodiment. FIG. 6 is a diagram corresponding to FIG. 4 according to the fifth embodiment. FIG. 7 is a diagram corresponding to FIG. 4 according to the sixth embodiment. FIG. 9 is a diagram corresponding to FIG. FIG. 10 is a partial enlarged cross-sectional view of a diameter reducing mechanism of Example 7.

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

  As shown in FIGS. 1 to 3, the clamp device C can drive the main body member 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 and an annular pressure receiving member 5 included in the hydraulic cylinder 4 are provided. The body member 1 includes an upper body member 11, a lower body member 12, and a base body member 13.

  The upper body member 11 is substantially oval in plan view, and the upper body member 11 is fixed to the base body member 13 with four bolts inserted into the four bolt holes 14. 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.

  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. Four arcuate seating surfaces 18 surrounding the grip member 2 are formed on the upper surface of the upper main body member 11, and the workpiece W can be seated on the seating surfaces 18 in a state where the workpiece W is clamped. On the upper surface of the upper body member 11, four concave grooves 19 through which air blow of pressurized air flows are formed in a cross shape. Except for the four seating surfaces 18 and the four concave grooves 19, the upper surface of the upper body member 11 is formed as a partial conical surface with a gentle inclination angle.

  The substantially annular grip member 2 is inserted into the hole H of the workpiece W and can grip the inner peripheral surface of the hole H. The grip member 2 includes a rod insertion hole 21 and a workpiece mounting surface 22 that can receive the workpiece W at a position on the advancing side (upper side) than the seating surface 18 when the grip member 2 is at the advancing position (upper limit position). An annular flange 23 forming the workpiece mounting surface 22, a grip claw 24 extending outward from the annular flange 23, and a base formed on the opposite side of the grip claw 24 with respect to the annular flange 23 An end collar 26 and an annular groove 25 formed between the annular collar 23 and the proximal collar 26 are provided. The grip member 2 includes four grip divisions 2b in which an annular flange 23, a grip claw 24, an annular groove 25, and a proximal flange 26 are divided into four equal parts in the circumferential direction by a slit 27.

The grip member 2 is made of a metal member, and in the grip member 2, three-step teeth 24 a that make it easy to grip the inner peripheral surface of the hole H of the workpiece W are provided on the outer peripheral surface of the grip claw portion 24 of each grip divided body 2 b. Is formed.
The grip member 2 is formed with a rod insertion hole 21 through which the clamp rod 3 is inserted, and a taper shaft portion 31 of the clamp rod 3 engages closely with a grip claw portion corresponding portion of the rod insertion hole 21. It is formed in the taper hole 21a.

As shown in FIGS. 1 to 3, a scraper 28 made of an elastic material such as rubber or synthetic resin that is slidably contacted with the outer peripheral surface of the annular flange 23 of the grip member 2 is mounted in the opening hole 17 of the upper body member 11. Yes. An O-ring 29 for urging the divided grip claw portion 24 and the annular flange portion 23 in the diameter reducing direction is attached to the annular groove 25 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 be moved up and down integrally with the annular pressure receiving member 5, and the horizontal direction orthogonal to the axial center of the hydraulic cylinder 4 through elastic deformation of the annular gap 7 on the outer peripheral portion of the circular recess 6 and the scraper 28. It is mounted so as to be movable.

  The clamp rod 3 includes a tapered shaft portion 31, a small diameter rod portion 32 continuous with the lower end of the tapered shaft portion 31, a large diameter rod portion 33 continuous with the lower end of the small diameter rod portion 32, and a lower end of the large diameter rod portion 33. A large-diameter flange portion 34 that is connected to is integrally formed. The tapered shaft portion 31 and the small diameter rod portion 32 are inserted into the rod insertion 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 51a.

  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 35 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 urge 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. It corresponds to “means”.

  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, and a grip member is provided on the upper surface of the horizontal plate portion 62. Two proximal end flanges 26 are placed to support the proximal end surface of the grip member 2. Here, the cylindrical piston rod 44 and the pressure receiving cylinder portion 61 correspond to an “annular portion”. 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 paths 66 to 69, and a hydraulic pressure detection sensor 70 that detects the hydraulic pressure of the oil path 69 is also provided. The unclamping oil chamber 46 is connected to a hydraulic pressure supply source via oil paths 71 and 72, and a hydraulic pressure detection sensor 73 that detects the hydraulic pressure of the oil path 72 is also provided. The annular pressure receiving member 5 includes a first position where the work mounting surface 22 of the grip member 2 is located outward (upward) from the seating surface 18, and a position where the work mounting surface 22 is retracted (lowered) from the seating surface 18. A predetermined stroke is movable in the axial direction over the second position.

  As shown in FIGS. 1 to 4, a seating sensor 80 that detects that the lower surface of the work W is in close contact with the seating surface 18 in a state where the work W is clamped is provided. The seating sensor 80 includes a pressurized air ejection hole 81 opened in the seating surface 18, an air passage 82 formed in the upper body member 11 so as to communicate with the pressurized air ejection hole 81, and the base body member 13. An air passage 83 formed therein, a pressurized air supply source for supplying pressurized air to the air passage 83, and detecting that the pressure of the pressurized air in the air passage 83 has increased to a predetermined value or more. A pressure switch 84 or the like is used.

  As shown in FIG. 1, an air passage 90 similar to the air passage 82 is formed in the upper main body member 11, and pressurized air is supplied from the air passage 90 to the circular recess 6 and the annular gap 25. The four slits 27 of the grip member 2 flow toward the four seating surfaces 18, and the four seating surfaces 18 are air blown to clean the seating surfaces 18.

Next, a clamp failure detection mechanism 100 for detecting a clamp failure will be described.
As shown in FIGS. 4 to 6, a shallow circular recess 101 is formed at the upper end of the lower body member 12 below the air passage 82 and the lower surface of the upper body member 11 is very opposed to the circular recess 101. A shallow circular recess 101a is formed. A circular valve plate 102 (valve member) that opens and closes the air passage 104 is mounted in the circular recesses 101 and 101a, and the valve plate 102 is biased to a position where the air passage 104 is closed upward on the lower surface side of the valve plate 102. An O-ring 103 (valve urging member) is mounted. An air passage 104 extending from the air passage 82 is formed, and pressurized air is supplied to the upper surface side of the valve plate 102.

  Since the circular recess 101a is formed, when the annular pressure receiving member 5 is lowered to the lower limit position, the locking rod 62a of the annular pressure receiving member 5 contacts the valve plate 102 so that the valve plate 102 is opened downward to open the air passage 104. It pushes (see FIG. 6). When the annular pressure receiving member 5 is not lowered to the lower limit position, the lower end of the air passage 104 is closed by the valve mechanism 105 including the valve plate 102 and the O-ring 103, so that the seating sensor 80 operates normally. However, when the annular pressure receiving member 5 is lowered to the maximum and the locking rod 62a pushes the valve plate 102 downward due to a clamping failure as will be described later, the valve mechanism 105 opens and the air passage 104 The pressurized air leaks into the accommodation hole 6 and leaks from the accommodation hole 6 to the opening hole 17, so that the air pressure in the air passages 82 and 104 does not increase.

In this way, by detecting that the seating sensor 80 does not detect the seating of the workpiece W even after the clamping operation, it is possible to detect a clamping failure as described later.
The hydraulic pressure supply source, the pressurized air supply source, the hydraulic pressure detection sensors 70 and 73, and the pressure switch 84 are electrically connected to a control unit (not shown) and controlled by the control unit.

  Here, when it is desired not to cause the clamping failure detection mechanism 100 to function, the valve plate 102 and the O-ring 103 may be mounted upside down in the circular recesses 101 and 101a as shown in FIG. Thus, since the upper end of the valve plate 102 is located below the upper end of the inner portion of the lower body member 12 than the circular recess 101, the annular pressure receiving member 5 is locked even if the annular pressure receiving member 5 is lowered to the lower limit position. Since the flange 62 a does not come into contact with the valve plate 102, the air passage 104 is kept closed by the O-ring 103.

The operation and effect of the clamping device C will be described.
When the workpiece W is fixed by the clamping device C, 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. Further, the annular pressure receiving member 5 holds the upper limit position for receiving the hydraulic pressure of the clamping oil chamber 45, the grip member 2 also holds the upper limit position, and the work mounting surface 22 maintains a position slightly higher than the seating surface 18. To do.

  In this state, the workpiece W is loaded, and the grip member 2 and the clamp rod 3 are inserted into the hole H of the workpiece W as shown in FIG. 2, and the workpiece W is supported by the workpiece mounting surface 22. In this way, the work W is initially supported by the work mounting surface 22 at a position higher than the seating surface 18, and then the work is supported by the seating surface 18 in the clamped state. Can be prevented from being damaged by the workpiece W, and the seating sensor 80 does not operate before clamping, and the seating sensor 80 is seated when the workpiece W is seated on the seating surface 18 and fixed with the intended clamping force. Since it comes to operate | move, the reliability of the seating sensor 80 can be improved.

  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. Since the piston member 42 is actuated and driven downward, the piston member 42 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 is engaged with the inner peripheral surface of the hole H of the workpiece W. 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. 3, the piston member 42, the grip member 2, the clamp rod 3, and the annular pressure receiving member 5 are integrally driven downward so that the workpiece W is seated on the seating surface 18 and is strongly pressed. Stop.

  At this time, as shown in FIG. 3, since a gap remains between the locking collar 62a of the annular pressure receiving member 5 and the lower main body member 12, the valve mechanism 105 of the clamp failure detection mechanism 100 is in a closed state. To maintain. Therefore, the seating sensor 80 can detect that the workpiece W is clamped with the desired clamping force and is seated on the seating surface 18.

  Here, the relationship between the operation in which the grip member 2 grips the workpiece W (the grip claw portion 24 bites on the inner peripheral surface of the hole H of the workpiece W) and the operation in which the workpiece W is clamped will be described in detail with reference to FIG. To do. In FIG. 8, FI is the hydraulic pressure supplied to the clamping oil chamber 45 and P2 is the hydraulic pressure supplied to the unclamping oil chamber 46, and FI indicates an upward force acting on the grip member 2 by the hydraulic pressure P <b> 1. A downward force acting on the clamp rod 3 by the hydraulic pressure P1 and the hydraulic pressure P2 is shown.

  Since the hydraulic pressure P1 is maintained constant from the beginning, FI is maintained at Fc, but after the workpiece W is supported by the mounting surface 18 and the grip member 2 and the clamp rod 3 are inserted into the hole H of the workpiece W. The hydraulic pressure P2 is reduced, and at that time, the force FII is applied downward to the clamp rod 3, and the force FII increases as the hydraulic pressure P2 decreases. Here, at least in a state where FII is lower than Fc, the grip member 20 receives FII from the clamp rod 3 and expands its diameter without being dragged downward by the clamp rod 3.

  When FII is larger than Fc, the grip member 2 and the clamp rod 3 are lowered integrally, and the clamping operation is started. Since the grip member 2 securely holds the workpiece W and the clamping operation can be started in this state because the diameter is increased, the grip claw portion 24 slips downward relative to the inner peripheral surface of the hole H of the workpiece W. This can be reliably prevented and the workpiece W can be reliably clamped.

  By the way, when the workpiece W is a cast product and the diameter of the hole H is not constant, and the hole H is increased in diameter downward, or when the workpiece W is made of a hard metal material, etc. When the oil pressure in the oil chamber 46 is set to the drain pressure and the piston member 42 and the like are started to be lowered, the grip claw portion 24 may slip downward relative to the inner peripheral surface of the hole H.

  In this case, as shown in FIGS. 5 and 6, although the workpiece W is seated on the seating surface 18, the annular pressure receiving member 5 is lowered to the lower limit position, so that the valve mechanism of the clamping failure detection mechanism 100 is opened. Since the air pressure in the air passages 82 and 104 does not increase and the pressure switch 84 of the seating sensor 80 does not turn on, it can be detected that the workpiece W is not correctly clamped. In this case, the workpiece W is in an incomplete clamping state, and a sufficient clamping force is not generated. Since the air supply system of the clamping failure detection mechanism 100 is configured in common with the air supply system of the seating sensor 80, the air supply system is simplified.

  On the other hand, when the workpiece W in the vertical orientation is clamped by the clamping device C arranged in the horizontal orientation, the clamping operation is performed with the gap between the workpiece W and the workpiece mounting surface 22 when the workpiece W is inserted. Even in this case, the amount of movement of the grip member 2 that moves until the workpiece W is seated on the seating surface 18 increases, and the valve mechanism 105 of the clamp failure detection mechanism 100 is opened as described above. From the above, a clamp failure can be detected via the seating sensor 80 as described above. Even when the workpiece is clamped with foreign matter sandwiched between the workpiece mounting surface 22 and the workpiece W, a clamping failure can be detected as described above.

  When the workpiece W is clamped by a plurality of clamping devices C, 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 or clamped, the shaft centers of the clamp rod 3 and the grip member 2 are displaced from the shaft center of the hydraulic cylinder 4 through elastic deformation of the scraper 28 and the O-ring 52.

  However, when the clamping device C is returned to the unclamped state after machining the workpiece W, the axial center of the clamp rod 3 and the grip member 2 is 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 the two upper and lower positions, the clamp rod 3 can be returned smoothly and without backlash. Since it is not necessary to manually perform the return operation for matching the axes, 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 to be removed. At this time, the scraper 28 mounted on the upper main body member 11 is positioned on the radially outer side than the teeth 24a of the grip member 2, so that the teeth 24a are This can be done without damaging the scraper 28.

  When the upper main 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. In particular, when the upper main body member 11 is mounted, the scraper 28 mounted on the upper main body member 11 is newly mounted. Since the grip member 2 is positioned radially outside the teeth 24a, the teeth 24a can be performed without damaging the scraper 28.

  In the present embodiment, the same components as those of the clamping device C are denoted by the same reference numerals, description thereof is omitted, and only different components are described. In the case where ribs are formed around the hole H of the workpiece W, the lower surface of the workpiece is not flat, so that when the clamp is clamped, the pressurized air ejection hole 81 of the seating surface 18 is formed on the workpiece W. It is not always sealed off at the bottom. In such a case, if the function of the seating sensor 80 is utilized, the seating sensor 80 will not detect the seating even if the seating sensor 80 is in the clamped state.

  Therefore, as shown in FIG. 9, in this clamping device CA, a portion other than the downstream portion of the air passage 82 is formed in an air passage 82a having a diameter larger than that of the downstream portion, and the rear of the large diameter air passage 82a is formed. By inserting a plug member 110 made of, for example, rubber or synthetic resin into the end portion, the function of the seating sensor 80 is stopped as necessary. However, pressurized air can be supplied to the clamp failure detection mechanism 100. It should be noted that the plug member 110 can be removed as necessary, for example, when the type of workpiece has changed.

  In the present embodiment, the same components as those of the clamping device C are denoted by the same reference numerals, description thereof is omitted, and only different components are described. This clamping device CB is provided with a clamping failure detection mechanism 100A having a configuration different from that of the clamping failure detection mechanism 100. As shown in FIG. 10, in the clamp device CB, the valve mechanism 105 is omitted, and the upper end portion of the lower body member 12 is pressurized at the portion facing the locking rod 62a of the annular pressure receiving member 5. An air ejection hole 120 and an air passage 121 connected to the pressurized air ejection hole 120 are formed.

  Air passages 122 and 123 that are different from the air passage 82 for the seating sensor 80 and are connected to the air passage 121 are formed in the upper body member 11. An air passage 124 connected to an air passage 123 is formed in the base body member 13, and this air passage 124 is connected to a pressurized air supply source, and the air pressure of the pressurized air in the air passage 124 becomes a predetermined value or more. A pressure switch 125 is also provided to detect that it has become.

  When the annular pressure receiving member 5 is lowered to the lower limit position due to a clamping failure, the pressurized air ejection hole 120 is closed by the locking rod 62a. Therefore, the pressure switch 125 detects the pressure rise of the pressurized air, and the clamping failure is detected. Can be detected. Since the valve mechanism 105 is omitted, a clamp failure detection mechanism 100A having a simple configuration is obtained.

  In the present embodiment, the same components as those of the clamping device C of the above embodiment are denoted by the same reference numerals, description thereof is omitted, and only different components are described. In this clamping device CC, a clamping failure detection mechanism 100B having a configuration different from that of the clamping failure detection mechanism 100 is provided. As shown in FIG. 11, in the clamping device CC, the valve mechanism 105 is omitted, and the upper body member 11 has a pressurized air ejection hole 130 formed at the lower end portion of the peripheral wall portion of the circular recess 6, Air passages 131 and 132 are formed.

  The base body member 13 is formed with an air passage 133 connected to the air passage 132. The air passage 133 is connected to a pressurized air supply source, and the air pressure of the pressurized air in the air passage 133 exceeds a predetermined value. A pressure switch 134 is also provided to detect that it has become. When the annular pressure receiving member 5 is lowered to the lower limit position due to a clamping failure, the pressurized air ejection hole 130 is closed by the locking rod 62a. Therefore, the pressure switch 134 detects the pressure rise of the pressurized air, and the clamping failure is detected. Can be detected. Since the valve mechanism 105 is omitted, a clamp failure detection mechanism 100B having a simple configuration is obtained.

  In the present embodiment, the same components as those of the clamping device C of the above embodiment are denoted by the same reference numerals, description thereof is omitted, and only different components are described. In this clamping device CD, a clamping failure detection mechanism 100D having a configuration different from that of the clamping failure detection mechanism 100 is provided. As shown in FIG. 12, in this clamping failure detection mechanism 100D, the valve mechanism 105D includes a valve member 102 that opens and closes the air passage 104 and a rod-like valve attached movably to the lower body member 12 of the clamp body 1. The urging member 140 includes a valve urging member 140 that urges the valve member 102 at a position where the air passage 104 is closed by receiving the hydraulic pressure supplied to the clamping oil chamber 45 of the fluid pressure cylinder 4. Is pushed by the locking rod 62a of the annular pressure receiving member 5 to be opened. The valve member 102 is the same as that in the first embodiment.

  A lower through-hole through-hole 141 is formed in the lower portion of the circular recess 101 of the lower body member 12, and the valve biasing member 140 is slidably inserted into the through-hole 141 while being sealed with an annular seal. The upper end portion of the valve urging member 140 is in contact with the valve member 102, and the lower end portion of the valve urging member 140 is located above the lower end of the through hole 141. According to this clamping device CD, the hydraulic pressure supplied to the fluid pressure cylinder 4 can be effectively used to urge the valve member 102, so that a clamping failure can be reliably detected, and the durability of the valve mechanism 105D is enhanced. be able to.

  In the present embodiment, the same components as those of the clamping device C of the above embodiment are denoted by the same reference numerals, description thereof is omitted, and only different components are described. In this clamping device CE, a clamping failure detection mechanism 100E having a configuration different from that of the clamping failure detection mechanism 100 is provided. As shown in FIG. 13, in this clamping failure detection mechanism 100E, the valve mechanism 105E moves to the valve member 102 that opens and closes the air passage 104, the lower body member 12 of the clamp body 1, and the piston portion 43 of the fluid pressure cylinder 2. A rod-like valve urging member 145 that is freely inserted, and receives the hydraulic pressure supplied to the clamping oil chamber 45 and the unclamping oil chamber 46 of the fluid pressure cylinder 2 so as to close the air passage 104. A valve urging member 145 that urges the valve 102, and the valve urging member 145 is positioned at a position where the air passage 104 is opened when the piston portion 43 is moved to the clamping direction limit position. It is comprised so that the member 102 can be moved. The valve member 102 is the same as that in the first embodiment.

  A large-diameter through hole 146a having a vertically penetrating shape is formed in a lower portion of the circular recess 101 of the lower main body member 12, and a small-diameter through hole having a smaller diameter than the large-diameter through hole 146a is coaxial with the large-diameter through hole 146a in the piston portion 43. 146a is formed. The valve urging member 145 includes a large-diameter shaft-shaped portion 145a formed in the upper half, a small-diameter shaft-shaped portion 145b formed in the lower half and having a smaller diameter than the large-diameter shaft-shaped portion 145a, and a lower end of the small-diameter shaft-shaped portion 145b. It has the latching hook part 145c formed in the part.

  The large-diameter shaft portion 145a is slidably inserted into the large-diameter through hole 146a while being sealed with an annular seal, the upper end portion of the large-diameter shaft portion 145a abuts the valve member 102, and the small-diameter shaft portion 145b. Is inserted into the small-diameter through hole 146b so as to be slidable in a state of being sealed with an annular seal, and the locking collar 145c is located below the piston 43, and the piston 43 moves to the clamping direction limit position. Then, the locking collar 145c is locked to the piston 43, and the valve urging member 145 moves downward to leave the valve member 102, where the valve member 102 moves downward due to its own weight or air pressure, The air passage 104 is opened.

The valve member 102 is also configured to be opened by being pushed by the locking rod 62a of the annular pressure receiving member 5, but this configuration can be omitted. According to the clamping device CE, the hydraulic pressure supplied to the fluid pressure cylinder 4 can be effectively used to urge the valve member 102, so that a clamping failure can be reliably detected, and the durability of the valve mechanism 105E is enhanced. it is possible.

  In the present embodiment, the same components as those of the clamping device C of the above embodiment are denoted by the same reference numerals, description thereof is omitted, and only different components are described. The clamp device CG includes a grip member 2G having a configuration different from that of the grip member 2 and a clamp rod 3A having a configuration different from that of the clamp rod 3. When the clamp device CG is returned from the clamped state to the unclamped state, there is provided a diameter reducing mechanism 170 that collects the plurality of grip division bodies 2d of the grip member 2G in a reduced diameter state close to the clamp rod 3A.

As shown in FIGS. 14 and 15 , the proximal end portion of the grip member 2G is formed with a tapered cylindrical portion 26b that protrudes downward from the inner peripheral portion of the proximal end flange portion 26a, and the outer peripheral surface of the tapered cylindrical portion 26b. Is formed on a tapered surface 26c that decreases in diameter toward the bottom. Since the grip member 2G is composed of four grip divided bodies 2d divided into four equal parts in the circumferential direction by the four slits 27 as in the grip member 2, the tapered cylindrical portion 26b is also circumferentially formed by the four slits 27. Divided into four equal parts.

As shown in FIG. 14 , a taper engaging portion 33a that engages with the tapered surface 26c of the tapered cylindrical portion 26b from below when the clamp is released is integrally formed at the upper end portion of the large-diameter rod portion 33 of the clamp rod 3A . . The inner surface of the taper engaging portion 33a is also formed as a tapered surface whose diameter increases toward the upper side, but the inclination angle of the taper surface with respect to the vertical direction is slightly larger than the inclination angle of the taper surface 26c with respect to the vertical direction. The diameter reducing mechanism 170 includes a taper engaging portion 33a of the clamp rod 3A and a taper surface 26c of the taper cylinder portion 26b.

  When the clamping device CG is changed from the clamped state to the unclamped state after machining with the workpiece W clamped, the shafts of the grip member 2G and the clamp rod 3A are moved to the hydraulic cylinder by the elastic force of the scraper 28 and the O-ring 52. The clamp rod 3 </ b> A is driven from the retracted direction to the advanced direction (upward) by the hydraulic cylinder 4 while moving in the horizontal direction so as to coincide with the axis 4. At this time, the taper engagement portion 33a of the clamp rod 3A engages with the taper surface 26c of the taper tube portion 26b of the grip member 2G in a close contact manner from below. For this reason, since the force for reducing the diameter of the tapered tube portion 26b acts on the tapered tube portion 26b from the taper engaging portion 33a, the four grip divided bodies 2d are pressed in the diameter reducing direction so as to approach the clamp rod 3A as much as possible. Thus, the grip member 2G is maximally reduced in diameter toward the clamp rod 3 side.

  As described above, the clamp device CG is provided with the diameter reducing mechanism 170, and the diameter reducing mechanism 170 has a tapered surface 26c formed so as to be reduced in diameter toward the tapered cylindrical portion 26b at the base end portion of the grip member 2G. In addition, since the clamp rod 3A is formed on the clamp rod 3A so as to be engageable with the taper surface 26c from below and has a taper engaging portion 33a whose diameter increases toward the top, the four grip divided bodies 2d are at the maximum on the clamp rod 3A when the clamp is released. Since the diameters are close to each other, the diameters of the four grip divided bodies 2d can be reliably reduced by the diameter reducing mechanism 170 each time the clamping device CG enters the unclamped state. Therefore, even when the grip claw portion 24 is engaged with the inner surface of the hole of the workpiece at the time of clamping, the grip member 2G can be surely reduced in diameter when the clamp is released, and the clamping of the workpiece by the clamping device CG is smoothly and efficiently performed. Can be done.

An example in which the embodiment described above is partially changed will be described.
1] Although the air passage 104 of the clamping failure detection mechanism 100 shown in FIG. 4 is connected to the air passage 82 for the seating sensor 80, the air passage 82 and the air passage 104 are connected to the air passage 104 as in FIGS. 8 and 9. Alternatively, pressurized air may be supplied from another air passage and detected by a similar pressure switch.
2] Instead of the hydraulic cylinder 4, an air cylinder that operates with pressurized air may be provided.
3] One of the clamp failure detection mechanism 100 and the seating sensor 80 may be omitted.
4] Those skilled in the art can implement the present invention by adding various modifications to the above-described embodiment, and the present invention includes such modifications.

  INDUSTRIAL APPLICABILITY The present invention can be used in a clamping device that clamps a workpiece by engaging a grip claw of a grip member with a hole of the workpiece and pulling it toward the seating surface.

W Work H Hole C, CA, CB, CC Clamp device CD, CE , CG Clamp device 1 Main body member 2 , 2 G Grip member 2b, 2d Grip split body 3, 3A Clamp rod 4 Hydraulic cylinder 5 Annular pressure receiving member 18 Seating surface 2 2 word over click mounting surface 23 annular flange portion 24 grip claw portion 26,26a base end flange portion 26b tapered tube portion 26c tapered surface 28 scraper 31 tapered shaft portion 33a tapering engagement portion 41 cylinder bore 42 the piston member 44 cylindrical Piston rod 45 Clamping oil chamber 46 Unclamping oil chamber 52 O-ring 80 Seating sensor 81 Pressurized air ejection hole
1 70 Diameter reduction mechanism

Claims (7)

An annular grip member that can be inserted into the hole of the workpiece and grip the inner peripheral surface of the hole, a clamp rod having a taper shaft portion fitted and engaged with the grip member, and the grip member and the clamp rod In a clamping device having a fluid pressure cylinder that can be driven back and forth in the center direction,
An upper body member and a lower body member to which the grip member, the clamp rod, and the fluid pressure cylinder are attached;
A seating surface formed on the upper body member for seating a workpiece;
A workpiece mounting surface formed on the grip member so that the workpiece can be received at a position closer to the advance side than the seating surface when the grip member is in the advanced position;
The fluid pressure cylinder includes a cylinder hole, a piston member attached to the cylinder hole and connected to the clamp rod, and a clamping fluid chamber and an unclamping fluid chamber formed in the cylinder hole,
The clamping device gripping member and the clamp rod, characterized in that it is movable integrally with the direction perpendicular to the axis of the fluid pressure cylinder. On the outer periphery of the clamp rod on the retracting side of the grip member, an annular portion that does not move in the direction orthogonal to the axis is provided with a gap that allows the clamp rod to move in the direction orthogonal to the axis,
Elasticity that is mounted between the annular portion and the clamp rod and elastically biases the clamp rod in a direction orthogonal to the axis so that the axes of the grip member and the clamp rod coincide with the axis of the fluid pressure cylinder. Provided with a ring member,
The clamping device according to claim 1, wherein: The clamping device according to claim 1, further comprising a pressurized air ejection hole for a seating sensor opened in the seating surface . The grip member includes an annular collar that forms the workpiece mounting surface, a grip claw that extends outward from the annular collar, and a proximal collar that is formed on the opposite side of the grip claw with respect to the annular collar. The clamp device according to claim 1 , wherein the grip member includes a plurality of grip divided bodies that are divided at a plurality of positions at equal intervals in the circumferential direction . The grip member is slidably contacted with the outer peripheral surface of the annular flange portion of the grip member, and the grip member is elastically attached in a direction orthogonal to the shaft center so that the axes of the grip member and the clamp rod coincide with the axis of the fluid pressure cylinder. The clamping device according to claim 4 , wherein a scraper made of elastic material is provided . The fluid pressure cylinder is configured to drive the clamp rod in the retracting direction when clamping and to drive the clamp rod in the advancing direction when releasing the clamp,
The clamp apparatus according to claim 4 , further comprising a diameter reducing mechanism that collects the plurality of grip division bodies of the grip member in a reduced diameter state close to a clamp rod when the clamp is released . The diameter-reducing mechanism is formed on the base end of the grip member so as to decrease in diameter toward the lower side, and is formed on the clamp rod so that the taper surface can be engaged from below, and the diameter increases toward the upper side. The clamp device according to claim 6 , further comprising a taper engaging portion .