Clamp device

Abstract

This clamp device comprises: a guide member (4) that is disposed in a housing (1); a valve operation member (40) that is inserted into a through-hole (47) formed in a circumferential wall of the guide member (4); an opening / closing valve (41) that is opened and closed by the valve operation member (40); a blowing-use air chamber (44) that is formed in the housing (1) and that communicates with a space outside the blowing-use air chamber (44) as a result of the opening / closing valve (41) being opened; and a communication passage (48) that communicates the blowing-use air chamber (44) and a clamped air chamber (12) or an unclamped air chamber (15).

Description

Clamping Device

[0001] The present invention relates to a device for clamping an object to be clamped, such as a workpiece.

[0002] One such clamping device is described in Patent Document 1. This conventional clamping device is configured as follows.

[0003] The clamping device described in Patent Document 1 includes a clamp body, a gripping member that is inserted into a hole in a workpiece to grip the inner peripheral surface of the hole, and a clamp rod having a tapered shaft that is internally fitted and engaged with the gripping member. A quick exhaust valve is provided to supply pressurized air to an air blow passage when the pressurized air is exhausted from the air actuation chamber.

[0004] JP 2014-50934 A

[0005] The air blow passage is, for example, a pipe indicated by reference numeral 33 in Fig. 1 of Patent Document 1. This pipe and the work pallet (a member indicated by reference numeral 1c in Fig. 1) are connected by an air blow port (a member indicated by reference numeral 19c in Fig. 1). The presence of such an air blow port increases the number of connections to the outside.

[0006] An object of the present invention is to provide a clamping device having an air blowing mechanism that can eliminate the need for an air blowing port.

[0007] In order to achieve the above object, the clamping device disclosed in the present application is configured as follows, for example, as shown in FIGS.

[0008] (1) The clamping device includes a housing 1, a locking member 24 that protrudes further toward the tip side than the housing 1 and can be inserted into a hole Wa of an object to be clamped W, a clamping rod 7 having a wedge surface 29 that engages with the locking member 24, a piston 6 provided on the clamping rod 7, a clamping air chamber 12 formed on the tip side or base end side of the piston 6, and an unclamping air chamber 15 formed on the base end side or tip side of the piston 6. This clamping device further includes a guide member 4 arranged within the housing 1 and having a cylindrical hole 4a into which the clamp rod 7 is inserted; a valve operating member 40 inserted into a through hole 47 formed in the peripheral wall of the guide member 4, the valve operating member 40 being moved within the through hole 47 as the clamp rod 7 is moved in the axial direction; an on-off valve 41 opened and closed by the valve operating member 40; a blow air chamber 44 formed within the housing 1, the blow air chamber 44 communicating with an outer space of the blow air chamber 44 when the on-off valve 41 is opened; and a communication passage 48 connecting the clamping air chamber 12 or the unclamping air chamber 15 with the blow air chamber 44, the communication passage 48 having a check valve 49 arranged therein.

[0009] The clamping device disclosed in the present application has the following advantages.

[0010] When pressurized air is supplied to the clamping air chamber or the unclamping air chamber, the pressurized air also flows into the blowing air chamber. The blowing air chamber functions as a tank for storing pressurized air. When the clamping device is subsequently driven to clamp or unclamp, the valve operating member opens the on-off valve. When the on-off valve is opened, the pressurized air stored in the blowing air chamber is ejected from the blowing air chamber, performing air blowing. The clamping device of the present invention can perform air blowing even without an air blowing port as described in Patent Document 1.

[0011] (2) In the clamping device of (1) above, the blow air chamber 44 may be formed on the base end side of the on-off valve 41 .

[0012] According to this configuration, the portion of the housing on the locking member side (tip side) can be made thinner, so the clamp device can be made smaller.

[0013] (3) In the clamping device of (1) or (2) above, the communication passage 48 is a communication passage that connects the unclamping air chamber 15 and the blowing air chamber 44, and the communication passage 48 may be connected to an unclamping air supply / discharge path 17 that supplies / discharges pressurized air to / from the unclamping air chamber 15.

[0014] The inner wall surfaces in front of and behind the piston in the housing become the wall surfaces of the clamping air chamber and the wall surfaces of the unclamping air chamber depending on the movement of the piston. With the above configuration, the communicating passage is not directly connected to the unclamping air chamber, which makes it easier to design the communicating passage.

[0015] (4) In the clamping device of (3) above, the communication passage 48 may be formed in the housing 1 .

[0016] With this configuration, the clamp device can be made smaller than when a communication passage is provided outside the housing.

[0017] (5) In the clamping device of (1) or (2) above, the communication passage 48 is a communication passage that connects the clamping air chamber 12 and the blowing air chamber 44, and the communication passage 48 may be connected to a clamping air supply / discharge path 14 that supplies / discharges pressurized air to / from the clamping air chamber 12.

[0018] The inner wall surfaces in front of and behind the piston in the housing become the wall surfaces of the clamping air chamber and the wall surfaces of the unclamping air chamber as the piston moves. With the above configuration, the communicating passage is not directly connected to the clamping air chamber, making it easier to design the communicating passage.

[0019] (6) In the clamping device of (5) above, the communication passage 48 may be formed in the housing 1 .

[0020] With this configuration, the clamp device can be made smaller than when a communication passage is provided outside the housing.

[0021] (7) In any of the clamping devices (1) to (6) above, the valve operating member 40 may be a sphere.

[0022] This configuration allows the on-off valve to be opened and closed more smoothly.

[0023] According to the present invention, it is possible to provide a clamp device having an air blow mechanism configured so that an air blow port can be eliminated.

[0024] FIG. 1 shows a first embodiment of the present invention and is a cross-sectional side view of a clamping device in an unclamped state. FIG. 2 is a cross-sectional side view of the clamping device in the middle of switching from an unclamped state to a clamped state. FIG. 3 is a cross-sectional side view of the clamping device in the clamped state. FIG. 4 shows a modified example of the first embodiment and is a cross-sectional side view of the clamping device in the unclamped state. FIG. 5 is a cross-sectional side view of the clamping device shown in FIG. 4 in the clamped state. FIG. 6 shows a second embodiment of the present invention and is a cross-sectional side view of the clamping device in the clamped state. FIG. 7 is a cross-sectional side view of the clamping device shown in FIG. 6 in the middle of switching from a clamped state to an unclamped state. FIG. 8 is a cross-sectional side view of the clamping device shown in FIG. 6 in the unclamped state. FIG. 9 shows a third embodiment of the present invention and is a cross-sectional side view of the clamping device in the clamped state. FIG. 10 is a cross-sectional side view of the clamping device shown in FIG. 9 in the unclamped state. FIG. 11 shows a modified example of the clamping device shown in FIG. 4 and is a cross-sectional side view of the clamping device in the clamped state. 12 is a cross-sectional side view of the clamping device shown in FIG. 11 in an unclamped state.

[0025] 1 to 3 show a first embodiment of the present invention. The clamping device of this embodiment is used to fix a workpiece W as an object to be clamped. The workpiece W is, for example, a steel plate used as a material for automobile panels, and has a thickness of, for example, about 1 mm to 2 mm. A hole Wa is drilled in the workpiece W.

[0026] The configuration of the clamping device of the first embodiment will be described with reference to FIGS. 1 to 3 . The terms "upper," "lower," "upper," and "lower" used in the following description refer to the case where the clamping device is positioned in the orientation shown in FIGS. 1 to 3 . The positions of the components and parts constituting the clamping device are not limited by the terms "upper," "lower," "upper," and "lower" used in the following description. The clamping device of the present invention may be positioned upside down, horizontally, or obliquely, instead of being positioned in the up-and-down orientation shown in FIGS. 1 to 3 . Furthermore, in FIGS. 1 to 3 , "upper" refers to the "distal side," "upper side" refers to the "distal side," "lower" refers to the "proximal side," and "lower side" refers to the "proximal side." The same applies to the descriptions of other embodiments.

[0027] The housing 1 is attached to a fixed base T such as a table. The housing 1 comprises a lower housing 2, a cover member 3 that hermetically closes the lower end opening of a cylinder bore 2a formed in the lower housing 2, and a cylindrical upper housing 5 that is fixed with bolts (not shown) to the top surface of the lower housing 2. The lower housing 2 has, in order from the bottom, the cylinder bore 2a and a large-diameter bore 2b that is larger in diameter than the cylinder bore 2a.

[0028] A piston 6 is hermetically inserted into the cylinder bore 2a, and a clamp rod 7 protrudes upward from the piston 6. The clamp rod 7 has a rod body 9 fixed to the piston 6 with a bolt 8, and a rod tip portion 11 connected to the tip of the rod body 9 via a pin member 10 so as to be movable in the radial direction of the rod body 9. Note that here, the rod body 9 and the piston 6 of the clamp rod 7 are separate parts, but the rod body 9 and the piston 6 may also be integrally molded. Similarly, the rod body 9 and the rod tip portion 11 are separate parts but may also be integrally molded.

[0029] Pressurized air is supplied to and discharged from a clamp chamber 12 formed above the piston 6 as an air chamber for clamping via an air supply / discharge port 13. The air supply / discharge port 13 and the clamp chamber 12 are connected by a clamp air supply / discharge path 14. Pressurized air is supplied to and discharged from an unclamping chamber 15 formed below the piston 6 as an air chamber for unclamping via another air supply / discharge port 16. The air supply / discharge port 16 and the unclamping chamber 15 are connected by an unclamping air supply / discharge path 17. The piston 6, clamp chamber 12, and unclamping chamber 15 together constitute a drive means (double-acting drive means) that drives the clamp rod 7 downward to clamp and upward to unclamp. A spring 18 serving as a biasing means is housed in the clamp chamber 12, and the spring 18 biases the clamp rod 7 downward via the piston 6.

[0030] A seat 19 for receiving the workpiece W is provided on the upper end surface of the upper housing 5 .

[0031] A support member 20 is inserted into the upper side of the upper housing 5 so as to be axially movable. This support member 20 has, in order from the bottom, a cylindrical portion 21, a peripheral wall portion 22 having a smaller diameter than the cylindrical portion 21, and a tapered top wall portion 23. The peripheral wall portion 22 and the top wall portion 23 protrude above the upper end of the upper housing 5 and are insertable into a hole Wa in the workpiece W.

[0032] Three guide holes 22a are formed in the peripheral wall portion 22 at 120° intervals in the circumferential direction, and a locking member 24 is inserted into each guide hole 22a so as to be movable radially. Each locking member 24 has, in order from the bottom, a base end portion 25, a base portion 26, and a protruding portion 27. The base end portion 25 is a portion that is supported from below by the cylindrical portion 21 that constitutes the support member 20. The outer peripheral surface of the protruding portion 27 protrudes radially outward beyond the outer peripheral surface 26a of the base portion 26. Note that only one of the three locking members 24 is shown in Figure 1 and other figures.

[0033] A protrusion 28 that protrudes radially inward is provided at the upper end of the upper housing 5. This protrusion 28 constitutes a relative movement limiting mechanism that limits the locking member 24 from moving radially outward beyond a predetermined amount relative to the clamp rod 7 when the clamp rod 7 is clamped downward. The hole diameter of the annular protrusion 28 is the same as the diameter of the hole Wa in the workpiece W. However, the hole diameter of the protrusion 28 may be smaller than the diameter of the hole Wa in the workpiece W.

[0034] The rod tip 11 of the clamp rod 7 is inserted into the tubular portion 21 and the peripheral wall portion 22 from below so as to be axially movable. A wedge surface 29 provided on the upper part of the rod tip 11 engages from above with an inclined surface 30 formed on the surface of the locking member 24 opposite the outer circumferential surface 26a. In other words, the wedge surface 29 engages with the locking member 24 from the tip side of the locking member 24. The wedge surface 29 and the inclined surface 30 are inclined downward so as to approach the axis of the clamp rod 7, and are formed as flat surfaces in this embodiment. In this embodiment, a total of three wedge surfaces 29 are formed every 120° in the circumferential direction of the clamp rod 7, the same number as the number of locking members 24.

[0035] A rod-side engaging groove 29a extending in the vertical direction along the wedge surface 29 is formed on the wedge surface 29, and a locking member-side engaging portion 30a extending in the vertical direction along the inclined surface 30 is formed on the inclined surface 30. The locking member-side engaging portion 30a fits into the rod-side engaging groove 29a, and the locking member-side engaging portion 30a and the rod-side engaging groove 29a constitute an engagement maintaining mechanism 31 that engages the wedge surface 29 of the clamp rod 7 with the inclined surface 30 of the locking member 24 so that they can move relative to each other.

[0036] The support member 20 is guided in the vertical direction by a linear guide mechanism 32. This linear guide mechanism 32 has a ball 33 attached to the outer peripheral surface of the cylindrical portion 21 that constitutes the support member 20, and a linear guide groove 34 formed in the vertical direction on the inner peripheral wall of the upper housing 5. The ball 33 is inserted into this linear guide groove 34.

[0037] An annular groove 35 is formed on the outer peripheral surface of the upper end of the cylindrical portion 21, and a retaining ring 36 serving as a ring-shaped elastic member is fitted into this annular groove 35. The annular groove 35 and the retaining ring 36 constitute a resistance applying mechanism 37 that applies resistance to the axial (vertical) movement of the support member 20. The portion designated by the reference symbol 36a is a slit portion of the retaining ring 36, which is a so-called C-shaped retaining ring. A complete ring-shaped retaining ring may be used instead of the C-shaped retaining ring as the ring-shaped elastic member. An annular groove 5a is formed on the inner peripheral surface of the upper housing 5, and the retaining ring 36 fits into the groove 5a in the unclamped state. An elastic member such as an O-ring may be used instead of the retaining ring 36. The annular groove 35 may also be formed on the outer peripheral surface of the cylindrical portion 21 other than the upper end.

[0038] A guide member 4 having a cylindrical bore 4a into which a clamp rod 7 is hermetically inserted is disposed within the housing 1. The guide member 4 has a main body cylindrical portion 38 and a flange portion 39 having a diameter larger than that of the main body cylindrical portion 38. A plurality of through holes 47 are formed in the peripheral wall of the main body cylindrical portion 38 at predetermined intervals in the circumferential direction. A ball 40 (sphere) serving as a valve operating member is inserted into each through hole 47. Each ball 40 is supported by the through hole 47 so that it can move between a radially inward position shown in FIG. 1 and a radially outward position shown in FIG. 3. The guide member 4 is fixed to the lower housing 2 by a retaining ring 45. Note that, although the lower housing 2 (housing 1) and the guide member 4 are separate components in this example, the lower housing 2 (housing 1) and the guide member 4 may be integrally molded.

[0039] The outer peripheral wall of the rod body 9 of the clamp rod 7 is formed with a retraction groove 9a, a push-out portion 9b, and a pressing surface 9c, which are connected vertically and correspond to each ball 40. The push-out portion 9b is formed to widen toward the tip side (direction away from the retraction groove 9a). When the pressing surface 9c moves to a position facing the ball 40, the ball 40 rides up onto the pressing surface 9c, and the ball 40 completely protrudes radially outward from the main body tubular portion 38 of the guide member 4. Furthermore, when the retraction groove 9a moves to a position facing the ball 40, the ball 40 becomes movable radially inward beyond the outer peripheral surface of the main body tubular portion 38. In this embodiment, three balls 40 are inserted into each of the through holes 47, but the number of balls 40 is not limited to three.

[0040] The on-off valve 41 is opened and closed by the ball 40. The valve body 42 of the on-off valve 41 is annular, and is disposed in the gap between the inner wall surface of the lower housing 2 and the outer peripheral surface of the tubular main body portion 38 of the guide member 4. An annular seal member 42a is attached to the outer peripheral surface of the valve body 42, and an annular seal member 42b is attached to the inner peripheral surface. The valve body 42 is urged upward by a spring 43 serving as urging means. A spring receiving portion 38a is provided on the outer peripheral surface of the tubular main body portion 38 of the guide member 4, and the spring 43 is attached between this spring receiving portion 38a and the valve body 42. A valve surface 42c is provided on the outer peripheral surface of the valve body 42, and a valve seat 2c is provided on a portion of the inner wall surface of the lower housing 2 facing the valve surface 42c.

[0041] A blow air chamber 44, from which pressurized air is ejected when the on-off valve 41 is opened, is formed below the on-off valve 41 in the lower housing 2. The flange 39 of the guide member 4 is hermetically fixed to the lower housing 2 by a sealing member 46, so that the pressurized air in the blow air chamber 44 does not escape through the flange 39.

[0042] A communication passage 48 that communicates between the blow air chamber 44 and the unclamping chamber 15 is formed in the lower housing 2. Here, the communication passage 48 is connected to the unclamping air supply / discharge path 17 that communicates between the air supply / discharge port 16 and the unclamping chamber 15. The communication passage 48 may also be directly connected to the unclamping chamber 15. A check valve 49 is disposed in the communication passage 48 near the blow air chamber 44. The check valve 49 is a check valve that allows pressurized air to flow from the unclamping chamber 15 to the blow air chamber 44 and blocks the flow of pressurized air in the opposite direction.

[0043] The clamping device having the above configuration operates as follows.

[0044] 1, pressurized air is discharged from the clamp chamber 12 and pressurized air is supplied to the unclamping chamber 15. This causes the piston 6 to move the clamp rod 7 upward to the unclamping position against the biasing force of the spring 18, and each locking member 24 is retracted radially inward by the engagement maintaining mechanism 31.

[0045] At this time, the outer peripheral surface of the protrusion 27 of the locking member 24 is set back more inward than the outer peripheral surface of the peripheral wall portion 22 of the support member 20, which prevents the peripheral wall of the hole Wa of the workpiece W from colliding with the locking member 24 when the workpiece W is carried in. When the workpiece W is lowered in the above-mentioned unclamped state, the hole Wa of the workpiece W is fitted externally with a predetermined gap between the peripheral wall portion 22 of the support member 20 and the locking member 24.

[0046] Furthermore, when pressurized air is supplied to the unclamping chamber 15, the pressurized air also flows through a communication passage 48 branching off from the unclamping air supply / discharge passage 17, and is also supplied to the blowing air chamber 44. The blowing air chamber 44 functions as a tank for storing pressurized air and is filled with pressurized air. Because the retraction groove 9a formed in the outer peripheral wall of the clamp rod 7 has been moved to a position facing the ball 40, the ball 40 is able to move within the through-hole 47. Therefore, the on-off valve 41 (valve body 42) is not pressed by the ball 40. Because the valve body 42 is biased upward by the spring 43, the valve surface 42c of the valve body 42 is pressed against the valve surface 42c, and the on-off valve 41 is closed.

[0047] When switching from the unclamped state shown in FIG. 1 to the clamped state shown in FIG. 3, the pressurized air in the unclamped chamber 15 is discharged and pressurized air is supplied to the clamped chamber 12, causing the piston 6 to descend.

[0048] As a result, the clamp rod 7 first moves downward as shown in Fig. 2. The support member 20 and the locking member 24 maintain the positions in the unclamped state shown in Fig. 1 or move slightly downward due to a frictional force corresponding to the elastic restoring force of the retaining ring 36 that constitutes the resistance applying mechanism 37.

[0049] As the clamp rod 7 descends, its wedge surface 29 pushes the locking member 24 radially outward, and the outer peripheral surface 26a of the base portion 26 of the locking member 24 contacts the inner peripheral surface of the hole Wa in the workpiece W or abuts against the inner peripheral surface of a protrusion 28 provided at the upper end of the upper housing 5. The rod tip 11 of the clamp rod 7 is movable horizontally relative to the rod body 9. Therefore, during clamping operation, the rod tip 11 and the locking member 24 move in a direction that brings the axis of the hole Wa in the workpiece W and the axis of the rod tip 11 closer together. In addition, the protrusion 27 that constitutes the locking member 24 faces the peripheral wall of the hole Wa from above.

[0050] Even if the pressurized air in the unclamping chamber 15 is discharged, the pressurized air filling the blow air chamber 44 will not be released from the communication passage 48. The check valve 49 arranged in the communication passage 48 functions to prevent the pressurized air in the blow air chamber 44 from being released.

[0051] When the locking member 24 abuts against the inner peripheral surface of the protrusion 28, the locking member 24 cannot move any further radially outward, so the wedge surface 29 of the clamp rod 7 presses the support member 20 downward via the locking member 24, and the locking member 24, support member 20, and clamp rod 7 descend together against the frictional force corresponding to the elastic restoring force of the retaining ring 36. Because the diameter of the hole in the protrusion 28 is the same as the diameter of the hole Wa in the workpiece W, the locking member 24 does not abut forcefully against the inner peripheral surface of the hole Wa in the workpiece W, which prevents damage to the inner peripheral surface of the hole Wa.

[0052] 3, the lower surface of the protrusion 27 of the locking member 24 reaches the upper surface of the peripheral wall of the hole Wa of the workpiece W, and the peripheral wall of the hole Wa is pressed against the seat portion 19 of the upper housing 5 by the protrusion 27 of the locking member 24. This clamps the workpiece W. The holding force of the workpiece W is increased by the biasing force of the spring 18 housed in the clamp chamber 12.

[0053] At this time, the ball 40, pushed outward by the pushing portion 9b formed on the clamp rod 7, presses the valve body 42 of the on-off valve 41 and rides up onto the pressing surface 9c. This causes the valve body 42 to descend, separating the valve surface 42c from the valve seat 2c and opening the on-off valve 41. When the on-off valve 41 opens, pressurized air stored in the blow air chamber 44 is ejected from between the valve seat 2c and the valve surface 42c into the upper housing 5. After flowing through the upper housing 5, the pressurized air is ejected from between the locking member 24 and the hole Wa in the workpiece W, and between the peripheral wall portion 22 of the support member 20 and the hole Wa in the workpiece W, among other places. This causes the locking member 24, the peripheral wall portion 22 of the support member 20, and the internal space of the upper housing 5 to be air-blown. When the pressure inside the blow air chamber 44 becomes equal to the external pressure, the ejection of pressurized air stops, and air blowing ends.

[0054] As described above, the clamping device of this embodiment can perform air blowing even without an air blowing port.

[0055] In this embodiment, the on-off valve 41 opens and air blowing begins at the timing when the clamped state shown in FIG. 3 is reached or at a timing close to that timing. The timing at which air blowing begins is not limited to this. By shifting the push-out portion 9b formed on the clamp rod 7 downward from the axial position shown in FIG. 1, the timing at which the on-off valve 41 opens can be advanced. This causes air blowing to begin at an earlier stage than the timing at which the clamped state is reached. By adjusting the axial position of the push-out portion 9b, air blowing can be started at a desired timing when switching from the unclamped state to the clamped state.

[0056] When switching from the clamped state shown in FIG. 3 to the unclamped state shown in FIG. 1, the pressurized air in the clamp chamber 12 is discharged and pressurized air is supplied to the unclamped chamber 15, causing the piston 6 to rise.

[0057] This first raises the clamp rod 7. The support member 20 and the lock member 24 are held in the clamped position (lowered position) shown in FIG. 3 by a frictional force corresponding to the elastic restoring force of the retaining ring 36 that constitutes the resistance applying mechanism 37.

[0058] As the clamp rod 7 rises, the upward movement of the locking member 24 is restricted by the support member 20 (the upward movement of the locking member 24 is restricted by the upper end surface of the guide hole 22a), and since the engagement maintaining mechanism 31 engages the wedge surface 29 of the clamp rod 7 and the locking member 24 so that they can move relative to each other, the wedge surface 29 causes the locking member 24 to retreat radially inward, and the protrusion 27 of the locking member 24 moves away from the peripheral wall of the hole Wa of the workpiece W in a direction toward the radially inward direction.

[0059] As the clamp rod 7 rises further, the upper end of the rod body 9 of the clamp rod 7 hits the inner top surface of the cylindrical portion 21 that constitutes the support member 20, and then the locking member 24, support member 20, and clamp rod 7 rise together against the frictional force corresponding to the elastic restoring force of the retaining ring 36. In other words, the clamp rod 7 moves the locking member 24 upward via the support member 20.

[0060] Thereafter, the upper end surface of the cylindrical portion 21 comes into contact with the inner top surface of the upper housing 5, and the upward movement of the clamp rod 7 stops, resulting in the unclamped state shown in FIG.

[0061] When the clamp rod 7 moves up, the retraction groove 9a formed in the clamp rod 7 moves to a position facing the ball 40, which becomes movable within the through-hole 47. The movement of the valve body 42 of the on-off valve 41 is no longer restricted by the ball 40, so the spring 43 below the valve body 42 pushes the valve body 42 upward, whereby the valve surface 42c of the valve body 42 is pressed against the valve surface 42c, and the on-off valve 41 is closed.

[0062] Furthermore, when pressurized air is supplied to the unclamping chamber 15, the pressurized air also flows into a communication passage 48 branching off from the unclamping air supply / discharge passage 17, and pressurized air is also supplied to the blowing air chamber 44. As a result, the blowing air chamber 44 is filled with pressurized air.

[0063] 4 and 5 show a modified example of the first embodiment. The clamping device of this modified example differs from the clamping device of the first embodiment as follows.

[0064] The clamping device of the first embodiment and the modified example differ in the shape of the locking member 24. The locking member 24 of the modified example does not have the protrusion 27 that is provided on the locking member 24 of the first embodiment. In the locking member 24 of the first embodiment, the protrusion 27 presses the peripheral wall of the hole Wa of the workpiece W from above. On the other hand, in the locking member 24 of the modified example, the outer peripheral surface of the locking member 24 abuts against the inner peripheral surface of the hole Wa, thereby clamping the workpiece W (see FIG. 5 ).

[0065] The clamp device of the modified example does not include the resistance applying mechanism 37 and the linear guide mechanism 32 that are included in the clamp device of the first embodiment.

[0066] The clamp device of the modified example includes a spring 50 as a biasing means that biases the locking member 24 upward via the support member 20. Here, the spring 50 is attached between the lower surface of the tubular portion 21 of the support member 20 and the upper surface of the main body tubular portion 38 of the guide member 4.

[0067] In the clamping device of this modification, as in the clamping device of the first embodiment, the on-off valve 41 opens and air blowing begins at the timing when the clamped state shown in Fig. 5 is reached or at a timing close to that timing. In addition, by adjusting the axial position of the pushing portion 9b formed on the clamp rod 7, air blowing can be started at a desired timing when switching from the unclamped state to the clamped state.

[0068] 6 to 8 show a second embodiment of the present invention. The clamping device of the second embodiment differs from the clamping device of the first embodiment as follows.

[0069] The difference between the first and second embodiments is the origin of a communication passage 48 that connects to the blow air chamber 44. In the second embodiment, the communication passage 48 is connected to a clamping air supply / discharge path 14 that connects the air supply / discharge port 13 and the clamp chamber 12. Note that the communication passage 48 is for connecting the clamp chamber 12 and the blow air chamber 44, and the communication passage 48 may be directly connected to the clamp chamber 12.

[0070] In the first embodiment, the extrusion portion 9b is formed above the retraction groove 9a, and the pressing surface 9c is formed above the extrusion portion 9b in the axial direction of the clamp rod 7. In the second embodiment, on the other hand, the extrusion portion 9b is formed below the retraction groove 9a, and the pressing surface 9c is formed below the extrusion portion 9b.

[0071] In the clamping device of the second embodiment, the on-off valve 41 opens and air blowing begins at the timing of, or close to, the unclamped state shown in FIG. 8 . Note that, as with the clamping device of the first embodiment, the timing at which air blowing begins is not limited to this. By shifting the push-out portion 9 b formed on the clamp rod 7 upward from the axial position shown in FIG. 6 , the timing at which the on-off valve 41 opens becomes earlier. This causes air blowing to begin at an earlier stage than the timing at which the unclamped state begins. By adjusting the axial position of the push-out portion 9 b, air blowing can be begun at a desired timing when switching from the clamped state to the unclamped state.

[0072] 6, pressurized air is discharged from the unclamping chamber 15 and pressurized air is supplied to the clamping chamber 12. When pressurized air is supplied to the clamping chamber 12, pressurized air also flows into the communication passage 48 branching off from the clamping air supply / discharge passage 14, and pressurized air is also supplied to the blowing air chamber 44, which is filled with pressurized air.

[0073] When switching from the clamped state shown in FIG. 6 to the unclamped state shown in FIG. 8, the pressurized air in the clamp chamber 12 is discharged and pressurized air is supplied to the unclamped chamber 15, causing the piston 6 to rise.

[0074] This causes the clamp rod 7 to rise. As the clamp rod 7 rises, the pushing portion 9b formed on the clamp rod 7 eventually pushes the ball 40 outward, and the ball 40 presses the valve body 42 of the on-off valve 41 and rides onto the pressing surface 9c (see Figures 7 and 8).

[0075] As a result, the valve body 42 descends, the valve surface 42c separates from the valve seat 2c, and the on-off valve 41 opens. When the on-off valve 41 opens, pressurized air stored in the blow air chamber 44 is ejected from between the valve seat 2c and the valve surface 42c toward the inside of the upper housing 5. After flowing inside the upper housing 5, the pressurized air is ejected from between the locking member 24 and the hole Wa of the workpiece W, and between the peripheral wall portion 22 of the support member 20 and the hole Wa of the workpiece W, etc. As a result, the locking member 24, the peripheral wall portion 22 of the support member 20, and the internal space of the upper housing 5 are air-blown. When the pressure inside the blow air chamber 44 becomes equal to the external pressure, the ejection of pressurized air stops, and air blowing ends.

[0076] 9 and 10 show a third embodiment of the present invention. The clamping device of the third embodiment differs from the clamping device of the second embodiment shown in FIGS. 6 to 8 as follows.

[0077] The main difference between the third embodiment and the second embodiment is the configuration and arrangement of the on-off valve 41.

[0078] The on-off valve 41 of the clamping device shown in Figures 9 and 10 includes a valve body 51, a first valve casing 52, a second valve casing 53, and a spring 54 as a biasing means. The valve body 51 is cylindrical and disposed within the cylindrical first valve casing 52. An annular seal member 51a is attached to the outer peripheral surface of the valve body 51. The valve body 51 is biased toward the ball 40 by the spring 54. A spring receiver 55 is provided within the first valve casing 52. A valve surface is provided on the outer peripheral surface of the seal member 51a, and a valve seat 52a corresponding to the valve surface is provided on the inner wall surface of the first valve casing 52. An annular seal member 52b is attached to the outer peripheral surface of the first valve casing 52, and an annular seal member 53a is attached to the outer peripheral surface of the second valve casing 53. An air passage 2d is provided in the upper portion (housing 1) of the lower housing 2, which corresponds to the lower portion of the first valve casing 52, and an air passage 52c is also provided in the first valve casing 52.

[0079] In the first and second embodiments, the on-off valve 41 is disposed inside the housing 1. In contrast to this, in the third embodiment, the on-off valve 41 is disposed in the housing 1 in a form that is embedded in the housing 1. A portion of the second valve casing 53 protrudes from the housing 1, making it easy for an operator to access the on-off valve 41. Note that the first valve casing 52 and the second valve casing 53 may be formed as an integrated unit rather than as separate parts.

[0080] In the third embodiment, similarly to the second embodiment, a pushing portion 9b is formed below the retraction groove 9a, and a pressing surface 9c is formed below the pushing portion 9b.

[0081] In the third embodiment, as in the second embodiment, the on-off valve 41 opens and air blowing begins at or near the timing of the unclamped state shown in FIG. 10 . Note that, as with the clamping device of the second embodiment, the timing of the start of air blowing is not limited to this. By shifting the push-out portion 9 b formed on the clamp rod 7 upward from the axial position shown in FIG. 9 , the timing at which the on-off valve 41 opens can be advanced. This causes air blowing to begin at an earlier stage than the timing at which the unclamped state is reached. By adjusting the axial position of the push-out portion 9 b, air blowing can be started at a desired timing when switching from the clamped state to the unclamped state.

[0082] 9, pressurized air is discharged from the unclamping chamber 15 and pressurized air is supplied to the clamping chamber 12. When pressurized air is supplied to the clamping chamber 12, pressurized air also flows into the communication passage 48 branching off from the clamping air supply / discharge passage 14, and pressurized air is also supplied to the blowing air chamber 44, which is filled with pressurized air.

[0083] When switching from the clamped state shown in FIG. 9 to the unclamped state shown in FIG. 10, the pressurized air in the clamp chamber 12 is discharged and pressurized air is supplied to the unclamped chamber 15, causing the piston 6 to rise.

[0084] This causes the clamp rod 7 to rise. As the clamp rod 7 rises, the pushing portion 9b formed on the clamp rod 7 eventually pushes the ball 40 outward, and the ball 40 presses the valve body 51 of the on-off valve 41 and rides onto the pressing surface 9c (see FIG. 10).

[0085] As a result, the valve body 51 moves to the right, separating the valve face (seal member 51a) from the valve seat 52a and opening the on-off valve 41. When the on-off valve 41 opens, pressurized air stored in the blow air chamber 44 flows through the air passage 2d and the air passage 52c, and then is ejected from between the valve seat 52a and the valve face (seal member 51a) into the upper housing 5. After flowing through the upper housing 5, the pressurized air is ejected from between the locking member 24 and the hole Wa in the workpiece W, and between the peripheral wall portion 22 of the support member 20 and the hole Wa in the workpiece W, among other places. As a result, the locking member 24, the peripheral wall portion 22 of the support member 20, and the internal space of the upper housing 5 are air-blown. When the pressure inside the blow air chamber 44 becomes equal to the external pressure, the ejection of pressurized air stops, and air blowing ends.

[0086] Figures 11 and 12 show a modified example of the clamp device shown in Figure 4. The differences between the clamp device of this modified example and the clamp device shown in Figure 4 are as follows.

[0087] In the clamp device shown in Fig. 4, the clamp rod 7 moves downward, causing the locking member 24 to clamp the workpiece W. Then, the clamp rod 7 moves upward, causing the clamp device to enter an unclamped state. In contrast, in the clamp device of the modified example shown in Figs. 11 and 12, the clamp rod 7 moves upward, causing the locking member 24 to clamp the workpiece W. Then, the clamp rod 7 moves downward, causing the clamp device to enter an unclamped state.

[0088] 4 and the clamping device of this modified example, the arrangement of the clamping chamber 12 and the unclamping chamber 15 is reversed. In the clamping device of this modified example, the clamping chamber 12 is formed below the piston 6, and the unclamping chamber 15 is formed above the piston 6.

[0089] In the clamp device of this modified example, the wedge surface 29 provided on the rod tip portion 11 and the inclined surface 30 provided on the locking member 24 are inclined so as to approach the axis of the clamp rod 7 as they extend upward. The wedge surface 29 engages with the locking member 24 from the base end side of the locking member 24.

[0090] 11, pressurized air is discharged from the unclamping chamber 15 and pressurized air is supplied to the clamping chamber 12. When pressurized air is supplied to the clamping chamber 12, pressurized air also flows into the communication passage 48 branching off from the clamping air supply / discharge passage 14, and pressurized air is also supplied to the blowing air chamber 44, which is filled with pressurized air.

[0091] When switching from the clamped state shown in FIG. 11 to the unclamped state shown in FIG. 12, the pressurized air in the clamp chamber 12 is discharged and pressurized air is supplied to the unclamped chamber 15, causing the piston 6 to descend.

[0092] This causes the clamp rod 7 to descend. As the clamp rod 7 descends, the pushing portion 9b formed on the clamp rod 7 eventually pushes the ball 40 outward, and the ball 40 presses the valve body 42 of the on-off valve 41 and rides onto the pressing surface 9c (see FIG. 12).

[0093] As a result, the valve body 42 descends, the valve surface 42c separates from the valve seat 2c, and the on-off valve 41 opens. When the on-off valve 41 opens, pressurized air stored in the blow air chamber 44 is ejected from between the valve seat 2c and the valve surface 42c toward the inside of the upper housing 5. After flowing inside the upper housing 5, the pressurized air is ejected from between the locking member 24 and the hole Wa of the workpiece W, and between the peripheral wall portion 22 of the support member 20 and the hole Wa of the workpiece W, etc. As a result, the locking member 24, the peripheral wall portion 22 of the support member 20, and the internal space of the upper housing 5 are air-blown. When the pressure inside the blow air chamber 44 becomes equal to the external pressure, the ejection of pressurized air stops, and air blowing ends.

[0094] In the clamp device of this modified example, as in the second embodiment, the on-off valve 41 opens and air blowing begins at the timing when the device enters the unclamped state shown in Fig. 12 or at a timing close to that timing. As in the clamp devices of the other embodiments, the timing at which air blowing begins is not limited to this. By adjusting the axial position of the extrusion portion 9b formed on the clamp rod 7, air blowing can be started at a desired timing when switching from the clamped state to the unclamped state.

[0095] The present invention is not limited to the above-described embodiments, and elements of the above-described embodiments can be appropriately combined or various modifications can be made to the above-described embodiments without departing from the spirit of the present invention.

[0096] For example, the above embodiment can be modified as follows.

[0097] In the clamp device of the second embodiment shown in Figures 6 to 8 and the clamp device of the third embodiment shown in Figures 9 and 10, a locking member 24 that does not have a protrusion 27 (see locking member 24 shown in Figure 1), as in the clamp device shown in Figures 4 and 5, may be used.

[0098] The clamping device shown in Figures 1 to 10 may be configured as a clamping device in which the locking member 24 clamps the workpiece W when the clamp rod 7 rises, and the clamping device is unclamped when the clamp rod 7 falls, as in the clamping device shown in Figures 11 and 12. Specifically, in the clamping device shown in Figures 1 to 10, the clamping chamber 12 may be formed below the piston 6, and the unclamping chamber 15 may be formed above the piston 6. Furthermore, the wedge surface 29 provided on the rod tip 11 and the inclined surface 30 provided on the locking member 24 may be inclined so as to approach the axis of the clamp rod 7 as they extend upward, as in the clamping device shown in Figures 11 and 12.

[0099] In the clamping device shown in Figures 1 to 5 and the clamping device shown in Figures 11 and 12, an on-off valve 41 having a cylindrical valve body 51 shown in Figures 9 and 10 may be used instead of the on-off valve 41 having the annular valve body 42.

[0100] The blow air chamber 44 is not limited to being formed below the on-off valve 41. The blow air chamber 44 can also be formed inside the upper housing 5.

[0101] In the above embodiment, the communication passage 48 is formed in the lower housing 2 (housing 1). Alternatively, the communication passage 48 may be formed of a pipe and may be formed outside the housing 1.

[0102] All of the clamp devices in the above embodiments are double-acting. The clamp devices shown in Figures 1 to 5, which include a communication passage 48 that connects the unclamping chamber 15 and the blow air chamber 44, may be spring-locked and single-acting instead of double-acting. Furthermore, the clamp devices shown in Figures 6 to 8, 9 and 10, and 11 and 12, which include a communication passage 48 that connects the clamping chamber 12 and the blow air chamber 44, may be spring-release and single-acting instead of double-acting.

[0103] One spring 18 is housed in the clamp chamber 12. The clamp chamber 12 may house a plurality of springs, or may not house any springs at all.

[0104] Instead of providing three locking members 24, two or four or more locking members 24 may be provided. Furthermore, the locking members may be formed of annular collets having slits.

[0105] Instead of the support member 20, a support member consisting of only the tubular portion 21 without the peripheral wall portion 22 and the top wall portion 23 may be used.

[0106] 1: Housing, 4: Guide member, 4a: Cylindrical hole, 6: Piston, 7: Clamp rod, 12: Clamp chamber (clamping air chamber), 14: Clamping air supply / discharge path, 15: Unclamping chamber (unclamping air chamber), 17: Unclamping air supply / discharge path, 24: Locking member, 29: Wedge surface, 40: Ball (valve operating member, sphere), 41: Open / close valve, 44: Blow air chamber, 47: Through hole, 48: Communication path, 49: Check valve, W: Workpiece (object to be clamped), Wa: Hole

Claims

1. A housing (1); a locking member (24) that protrudes further toward the tip side than the housing (1) and is insertable into a hole (Wa) of an object to be clamped (W); a clamp rod (7) having a wedge surface (29) that engages with the locking member (24); a piston (6) provided on the clamp rod (7); a clamping air chamber (12) formed on the tip side or base end side of the piston (6); an unclamping air chamber (15) formed on the base end side or the tip side of the piston (6); a guide member (4) disposed within the housing (1) and having a cylindrical hole (4a) into which the clamp rod (7) is inserted; a valve operating member (40) inserted into a through hole (47) formed in a peripheral wall of the guide member (4), the valve operating member (40) being moved within the through hole (47) as the clamp rod (7) is moved in the axial direction; and an on-off valve (41) that is opened and closed by the valve operating member (40). a blow air chamber (44) formed in the housing (1), the blow air chamber (44) communicating with an outer space of the blow air chamber (44) when the on-off valve (41) is opened; and a communication passage (48) communicating the clamping air chamber (12) or the unclamping air chamber (15) with the blow air chamber (44), the communication passage (48) having a check valve (49) disposed therein.

2. The clamp device according to claim 1, wherein the blow air chamber (44) is formed on the base end side of the on-off valve (41).

3. A clamping device according to claim 1 or 2, wherein the communication passage (48) is a communication passage that connects the unclamping air chamber (15) and the blowing air chamber (44), and the communication passage (48) is connected to an unclamping air supply / discharge path (17) for supplying / discharging pressurized air to / from the unclamping air chamber (15).

4. A clamping device according to claim 3, wherein the communication passage (48) is formed in the housing (1).

5. A clamping device according to claim 1 or 2, wherein the communication passage (48) is a communication passage that connects the clamping air chamber (12) and the blowing air chamber (44), and the communication passage (48) is connected to a clamping air supply / discharge path (14) for supplying / discharging pressurized air to / from the clamping air chamber (12).

6. A clamping device according to claim 5, wherein the communication passage (48) is formed in the housing (1).

7. A clamping device according to any one of claims 1 to 6, wherein the valve operating member (40) is a sphere.

Images