JP2009190169A - Clamp device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of a device provided with a seat surface and a seating sensor for a workpiece to be seated, wherein a clamping defect is not detected by the seating sensor, while breakage of a tool or damage of the workpiece is caused by the clamp defective. <P>SOLUTION: The clamp device C comprises: a grip member 2 that is a circular clamp member to be inserted into a hole H of the workpiece W to grip the inner circumferential surface of the hole; a clamp rod 3 having a taper shaft part 31 engaged inside the grip member 2; a fluid pressure cylinder 4 to drive the grip member 2 and the clamp rod 3 in the axial center direction forward and backward; and a main body member 1. The device is further provided with: the seat surface 18 formed on the main body member 1 on which the workpiece W is seated; and a clamping defect detecting mechanism to detect a clamping defect when the grip member 2 is driven by the fluid pressure cylinder 4 in the clamping direction through the clamp rod 3 until the workpiece W is seated on the seat surface 18. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a clamping device provided with clamping failure detection means for detecting clamping failure, and more particularly to a clamping 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. It relates to a suitable one.

  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. This type of clamping device is described in Patent Documents 1 and 2.

  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 secured 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 has risen above a set pressure. It is comprised with the pressure switch etc. which detect this.

Japanese Patent No. 355010 German Patent No. 4020981

  The seating sensor only detects that the workpiece is seated on the seating surface, so even if the seating sensor detects the seating of the workpiece on the seating surface, the workpiece is fixed with the desired clamping force. Not necessarily. For example, in the case of the above-mentioned hole clamp device, when clamping the clamp rod in the retracting direction at the time of clamping and expanding the grip claw portion of the grip member with the taper shaft portion, In addition, the grip claw portion may slip with respect to the hole of the workpiece while the workpiece is kept seated on the seating surface. In particular, when the workpiece is a cast product and the hole is formed in a slightly tapered hole, slip of the grip claw portion is likely to occur.

  When the grip claw slip as described above occurs, the piston member of the fluid pressure cylinder moves back to the retreat limit position, so that the workpiece is clamped with a significantly reduced clamping force. However, even in this case, since the workpiece holds the seat on the seating surface, the above-described clamping failure cannot be detected by the seating sensor. When machining a workpiece with such a clamping failure, the workpiece is displaced due to the cutting force acting from the cutting tool, which causes a problem that the cutting tool is broken or the workpiece is damaged.

  An object of the present invention is to provide a clamping device that can reliably detect a clamping failure in a state where a workpiece is seated on a seating surface.

  The clamp apparatus of Claim 1 has a clamp member for fixing a workpiece | work, the fluid pressure cylinder which can drive this clamp member forward / backward, and the main body member to which the said clamp member and a fluid pressure cylinder are attached. A clamping surface formed on the main body member for seating the workpiece, and a clamping failure detection means for detecting a clamping failure in a state where the clamping member is driven in the clamping direction by the fluid pressure cylinder and the workpiece is seated on the seating surface. It is characterized by having.

  When the workpiece is clamped, if the clamp member is driven in the clamping direction by the fluid pressure cylinder and the workpiece is seated on the seating surface, the clamping failure detection means detects the clamping failure in the seated state of the workpiece.

  The clamp device according to claim 2 includes a grip member that is an annular clamp member that can be inserted into a hole of a workpiece and grip an inner peripheral surface of the hole, and a taper shaft portion that is fitted and engaged with the grip member. In the clamp device, comprising: a rod, a fluid pressure cylinder capable of driving the grip member and the clamp rod back and forth in an axial direction, and a body member provided with the grip member, the clamp rod, and the fluid pressure cylinder. A seating surface formed on the member for seating the workpiece, and a clamping failure detection means for detecting a clamping failure in a state where the gripping member is driven in the clamping direction via the clamp rod by the fluid pressure cylinder and the workpiece is seated on the seating surface. It is characterized by having.

  When the workpiece is clamped, the grip member, which is a clamp member, is driven in the clamping direction via the clamp rod by the hydraulic cylinder, and the workpiece is seated on the seating surface. Detect clamp failure.

  According to a third aspect of the present invention, there is provided the clamping device according to the first or second aspect, wherein an interlocking member that moves integrally with the clamping member in the axial direction of the fluid pressure cylinder is provided. A valve mechanism that is opened by the interlocking member when moved to a clamping direction limit position or a position near the clamp direction, an air passage that supplies pressurized air to an input side of the valve mechanism, and a pressurized air in the air passage And a pressure switch for detecting that the pressure is equal to or higher than a set pressure.

  According to a fourth aspect of the present invention, there is provided the clamping device according to the first or second aspect, wherein an interlocking member that moves integrally with the clamping member in the axial direction of the fluid pressure cylinder is provided. Pressurized air ejection hole sealed by the interlocking member when moved to the clamping direction limit position or a position in the vicinity thereof, an air passage for supplying pressurized air to the pressurized air ejection hole, and pressurization of the air passage And a pressure switch for detecting that the air pressure is equal to or higher than a set pressure.

  According to a fifth aspect of the present invention, there is provided the clamping device according to any one of the first to fourth aspects, further comprising a seating sensor including a pressurized air ejection hole opened in the seating surface.

  According to a sixth aspect of the present invention, in the invention of the second aspect, when the grip member is driven in the clamping direction by the fluid pressure cylinder via the clamp rod, the grip member is in contact with the inner peripheral surface of the hole of the workpiece. When slipping, the grip member moves to the clamping direction limit position.

  According to a seventh aspect of the present invention, there is provided the clamping device according to the third aspect, wherein a passage portion branched from the air passage of the clamping failure detecting means and a pressurized air ejection hole communicating with the passage portion and opened in the seating surface are provided. It is characterized in that a seating sensor is provided.

  The clamp device according to claim 8 is the invention according to claim 3, wherein the valve mechanism includes a valve member that opens and closes the air passage, and an elastic valve biasing member that biases the valve member to a position where the air passage is closed. The valve member is pushed by the interlocking member to be opened.

  According to a ninth aspect of the present invention, in the invention of the third aspect, the valve mechanism includes a valve member that opens and closes the air passage, and a rod-shaped valve biasing member that is movably mounted on the clamp body. A valve urging member that urges the valve member to receive the fluid pressure supplied to the fluid pressure cylinder and closes the air passage is opened, and the valve member is pushed by the interlocking member to be opened. It is characterized by.

  According to a tenth aspect of the present invention, in the invention of the third aspect, the valve mechanism includes a valve member that opens and closes the air passage, and a rod-shaped valve biasing member that is movably inserted into a piston of the fluid pressure cylinder. A valve urging member for urging the valve member at a position to close the air passage upon receiving the fluid pressure supplied to the fluid pressure cylinder, and the valve urging member is integrated with the clamp member. When the piston as the pushing member moves to a clamp direction limit position, the piston is configured to move to a position where the piston portion is engaged and the air passage is opened.

  According to the first aspect of the present invention, in the clamping device having the clamp member, the fluid pressure cylinder capable of driving the clamp member forward and backward, and the main body member, the seating surface formed on the main body member for seating the workpiece, and the fluid pressure Since the clamping member is driven in the clamping direction by the cylinder and the clamping failure detecting means for detecting the clamping failure in the state where the workpiece is seated on the seating surface is provided, the workpiece is seated on the seating surface when clamping the workpiece. The clamping failure in the state can be detected by the clamping failure detection means. The clamping failure includes a clamping state in which a sufficient clamping force is not generated. Since the clamping failure as described above can be detected, the breakage of the tool and the workpiece caused by the clamping failure can be prevented.

  According to the invention of claim 2, the clamp device is an annular clamp member that can be inserted into the hole of the work and can grip the inner peripheral surface of the hole, and a taper that is fitted and engaged with the grip member. A clamp rod having a shaft portion; a fluid pressure cylinder capable of driving the grip member and the clamp rod forward and backward in an axial direction; and a main body member provided with the grip member, the clamp rod, and the fluid pressure cylinder.

  This clamping device has a seating surface formed on the main body member for seating the workpiece, and a clamping failure in a state where the gripping member is driven in the clamping direction via the clamp rod by the fluid pressure cylinder to seat the workpiece on the seating surface. Since the clamping failure detection means for detecting is provided, the clamping failure detection means in the state where the workpiece is seated on the seating surface can be detected by the clamping failure detection means when the workpiece is clamped, as in the first aspect of the invention. . The clamping failure includes a clamping state in which a sufficient clamping force is not generated. Since the clamping failure as described above can be detected, the breakage of the tool and the workpiece caused by the clamping failure can be prevented.

  According to the third aspect of the present invention, the interlock member that moves in the axial direction of the fluid pressure cylinder is provided integrally with the clamp member, and the clamp failure detection means moves the clamp member to the clamp direction limit position or a position in the vicinity thereof. A valve mechanism that is sometimes opened by an interlocking member, an air passage that supplies pressurized air to the input side of the valve mechanism, and a pressure that detects that the pressurized air pressure in the air passage is equal to or higher than a set pressure Since it has a switch, it is possible to realize a clamping failure detection means that operates reliably with a simple configuration.

  According to the fourth aspect of the present invention, the interlocking member that moves in the axial direction of the fluid pressure cylinder is provided integrally with the clamp member, and the clamp failure detection means moves the clamp member to the clamp direction limit position or a position in the vicinity thereof. A pressurized air ejection hole that is sometimes blocked by the interlocking member, an air passage for supplying pressurized air to the pressurized air ejection hole, and detecting that the pressurized air pressure in the air passage is equal to or higher than a set pressure Since it has a pressure switch, it is possible to realize a clamping failure detection means that operates reliably with a simple configuration.

  According to the invention of claim 5, since the seating sensor including the pressurized air ejection hole opened in the seating surface is provided, the seating of the workpiece on the seating surface can be detected by the seating sensor.

  According to the invention of claim 6, when the grip member is driven in the clamping direction by the fluid pressure cylinder via the clamp rod, when the grip member slips with respect to the inner peripheral surface of the hole of the workpiece, the grip member is Since it moves to the clamping direction limit position, it is possible to detect the clamping failure when the grip member slips with respect to the inner peripheral surface of the hole of the workpiece by the clamping failure detection means.

  According to a seventh aspect of the present invention, there is provided a seating sensor including a passage portion branched from the air passage of the clamping failure detection means, and a pressurized air ejection hole that communicates with the passage portion and is opened in the seating surface. Therefore, most of the air passages of the clamping failure detection means and the seating sensor can be shared, and the clamping failure detection means and the detection unit of the seating sensor can be shared.

  According to an eighth aspect of the present invention, the valve mechanism includes a valve member that opens and closes the air passage, and an elastic valve biasing member that biases the valve member to a position where the air passage is closed. Since the member is pushed by the interlocking member to open the valve, the valve member can be reliably urged to the position where the air passage is closed by the elastic valve urging member.

  According to a ninth aspect of the present invention, the valve mechanism is a valve member that opens and closes the air passage, and a rod-shaped valve biasing member that is movably mounted on the clamp body, and is supplied to the fluid pressure cylinder. A valve urging member that urges the valve member at a position that receives the fluid pressure and closes the air passage, and the valve member is pushed by the interlocking member to open the valve. The clamped hydraulic pressure can be effectively used to urge the valve member, so that a clamping failure can be reliably detected, and the durability of the valve mechanism can be enhanced.

  According to a tenth aspect of the present invention, the valve mechanism includes a valve member that opens and closes the air passage, and a rod-shaped valve urging member that is movably inserted into a piston of the fluid pressure cylinder. A valve urging member that urges the valve member at a position that receives the fluid pressure supplied to the cylinder and closes the air passage, and the valve urging member is integrated with the clamp member as the pushing member; When the piston moves to the clamping direction limit position, it is configured to move to a position where the piston is locked to open the air passage, so that the hydraulic pressure supplied to the fluid pressure cylinder is attached to the valve member. It is possible to effectively detect the failure of the clamp and reliably improve the durability of the valve mechanism.

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 clamping operation | work and clamping operation | work of the workpiece | work W. 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.

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

  As shown in FIGS. 1 to 3, the clamp device C includes a main body member 1, a grip member 2 that is a clamp member for fixing the workpiece W, a clamp rod 3, the grip member 2, and the clamp rod 3. A hydraulic cylinder 4 that can be driven in the axial direction (vertical direction) 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 main body member 11, four concave grooves 19 through which an air blow flow 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 has an annular flange 23, a grip claw 24, an annular groove 25, and a proximal end flange 26 divided into four equal parts by four slits 27.

The grip member 2 is formed of a metal member, and three-step teeth 24 a that make it easy to grip the inner peripheral surface of the hole H of the workpiece W are formed on the outer peripheral surface of the four divided claw portions of the grip claw portion 24. .
A rod insertion hole 21 through which the clamp rod 3 is inserted is formed in the grip member 2, and the taper shaft portion 31 of the clamp rod 3 is in close contact with the 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 is attached to the opening hole 17 of the upper body member 11 so as to be in sliding contact with the outer peripheral surface of the annular flange 23 of the grip member 2. 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 52.

  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 51 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. 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 annular pressure receiving member 5 corresponds to a “linkage member” that moves integrally with the grip member 2 in the axial direction of the hydraulic cylinder 4.

  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 a pressure for detecting that the pressure of the pressurized air in the air passage 83 has increased to a set pressure or higher. The switch 84 is configured.

  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 groove 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 grip member 2 is retracted to the lower limit position (clamping direction limit position) and the annular pressure receiving member 5 is lowered to the lower limit position, the locking rod 62a of the annular pressure receiving member 5 is the valve plate 102. The valve plate 102 is pushed downward to a position where the air passage 104 is opened (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 valve mechanism 105 may be configured to open when the grip member 2 is retracted to a position near the clamping direction limit position and the annular pressure receiving member 5 is lowered to a position near the lower limit position. .
The hydraulic pressure supply source, the 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 work 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 clamps 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, F1 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 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.

  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. Therefore, when clamping, 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 end of the large diameter air passage 82a. By inserting a plug member 110 made of, for example, rubber or synthetic resin into the 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 exceeds a set pressure. 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.

  An air passage 133 connected to the air passage 132 is formed in the base body member 13, and this 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 the set pressure. 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 addition, you may comprise so that the pressurized air ejection hole 130 may be closed when the cyclic | annular pressure receiving member 5 descend | falls to the position near the lower limit position.

  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-shaped valve urging member 145 that is freely inserted, and that receives the hydraulic pressure supplied to the clamping oil chamber 45 and the unclamping oil chamber 45 of the fluid pressure cylinder 2 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 that is coaxial with the large-diameter through hole 146a and smaller in diameter than the large-diameter through-hole 146a. 146a is formed. The valve urging member 145 includes a large-diameter shaft portion 145b formed in the upper half portion, a small-diameter shaft portion 145b formed in the lower half portion and having a smaller diameter than the large-diameter shaft portion 145a, and a lower end of the small-diameter shaft portion 145b. It has a locking collar 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 on 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 while being sealed with an annular seal, 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. 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. The clamp device CF includes a grip member 2F having a configuration different from that of the grip member 2 and can receive a workpiece W at a position closer to the advancing side than the seating surface 18 when the grip member 2F is at the advanced position. 161, and a workpiece mounting surface forming member 160 that is disposed on the outer peripheral side of the grip member 2F and moves in the axial direction integrally with the grip member 2F. The grip member 2F is obtained by omitting the base end flange portion 26 of the grip member 2.

  The workpiece mounting surface forming member 160 is formed by being appropriately divided (for example, divided into four parts) in the circumferential direction, and therefore does not affect the formation of the pressurized air ejection hole 130. The plurality of divided portions of the workpiece mounting surface forming member 160 are fixed to the upper surface of the annular pressure receiving member 5 with bolts or the like, and are provided so as to protrude upward from the portion main body member 11, and the upper end surface of the workpiece mounting surface forming member 160 is smooth It is formed on the surface 161. The part main body member 11 is formed with holes for projecting a plurality of divided parts of the workpiece mounting surface forming member 160.

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 pressure switch similar to that shown in FIGS.
2] Instead of the hydraulic cylinder 4, it is also possible to provide an air cylinder that operates with pressurized air.
3] At least 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 embodiments, 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 in a hole of the workpiece and pulling the grip member toward a seating surface.

W Work H Hole C, CA, CB, CC, CD, CE, CF Clamp device 1 Main body member 2, 2F Grip member 3 Clamp rod 4 Hydraulic cylinder 5 Annular pressure receiving member 18 Seating surface 22, 161 Work mounting surface 23 Annular collar 24 Grip claw portion 26 Base end flange portion 28 Scraper 31 Tapered shaft portion 41 Cylinder hole 42 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 100 , 100A, 100B, 100D, 100E Clamp failure detection mechanism 104, 83 Air passage 84 Pressure switch 105, 105D, 105E Valve mechanism 120 Pressurized air ejection holes 121-124 Air passage 125 Pressure switch 130 Pressurized air ejection holes 131-133 Air passage 134 Pressure switch

Claims (10)

In a clamp device having a clamp member for fixing a workpiece, a fluid pressure cylinder capable of advancing and retracting the clamp member, and a main body member to which the clamp member and the fluid pressure cylinder are attached,
A seating surface formed on the body member for seating a workpiece;
Clamp failure detection means for detecting a clamp failure in a state where the workpiece is seated on the seating surface by driving the clamp member in the clamping direction by the fluid pressure cylinder;
A clamping device comprising: A grip member that is an annular clamp 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, and the grip member and the clamp In a clamp device comprising a fluid pressure cylinder capable of driving the rod forward and backward in the axial direction, and a main body member to which the grip member, the clamp rod and the fluid pressure cylinder are attached,
A seating surface formed on the body member for seating a workpiece;
Clamp failure detection means for detecting a clamp failure in a state in which the grip member is driven in the clamping direction via a clamp rod by the fluid pressure cylinder and the workpiece is seated on the seating surface;
A clamping device comprising: An interlocking member that moves integrally with the clamp member in the axial direction of the fluid pressure cylinder;
The clamping failure detection means supplies a pressurized air to a valve mechanism that is opened by the interlocking member when the clamping member moves to a clamping direction limit position or a position in the vicinity thereof, and an input side of the valve mechanism. The clamp device according to claim 1, further comprising an air passage and a pressure switch that detects that the pressurized air pressure in the air passage is equal to or higher than a set pressure. An interlocking member that moves integrally with the clamp member in the axial direction of the fluid pressure cylinder;
The clamping failure detection means supplies pressurized air to the pressurized air ejection hole and the pressurized air ejection hole sealed by the interlocking member when the clamping member moves to the clamping direction limit position or a position in the vicinity thereof. The clamp device according to claim 1, further comprising: an air passage configured to detect the pressure and a pressure switch that detects that a pressure of the pressurized air in the air passage is equal to or higher than a set pressure.   The clamping device according to any one of claims 1 to 4, further comprising a seating sensor including a pressurized air ejection hole opened in the seating surface.   When the gripping member is driven in the clamping direction via the clamp rod by the fluid pressure cylinder, the gripping member moves to the clamping direction limit position when the gripping member slips with respect to the inner peripheral surface of the hole of the workpiece. The clamping device according to claim 2, wherein:   The seating sensor including a passage portion branched from the air passage of the clamp failure detecting means and a pressurized air ejection hole communicating with the passage portion and opened on the seating surface is provided. The clamping device as described.   The valve mechanism includes a valve member that opens and closes the air passage, and an elastic valve urging member that urges the valve member to a position where the air passage is closed, and the valve member is pushed by the interlocking member. 4. The clamp device according to claim 3, wherein the valve is operated to open.   The valve mechanism includes a valve member that opens and closes the air passage, and a rod-shaped valve biasing member that is movably mounted on the clamp body, and receives the fluid pressure supplied to the fluid pressure cylinder to receive the air passage. The clamp device according to claim 3, further comprising a valve urging member that urges the valve member at a position where the valve member is closed, and the valve member is pushed by the interlocking member to be opened. The valve mechanism is a valve member that opens and closes the air passage, and a rod-shaped valve biasing member that is movably inserted into a piston of the fluid pressure cylinder, and receives the fluid pressure supplied to the fluid pressure cylinder. A valve biasing member that biases the valve member at a position to close the air passage,
The valve urging member is configured to be able to move the valve member to a position where it is locked by the piston portion and opens the air passage when the piston moves to a clamping direction limit position. The clamping device according to claim 3.