JPS6023921B2 - Check - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a chuck device that is attached to the main shaft of a machine tool and grips a workpiece. This invention relates to a chuck that is designed to grip with uniform force, and also relates to a chuck that is designed to grip workpieces with large variations in diameter with a constant strong force.

Chucks for gripping workpieces with large variations in the diameter of the follower can be roughly divided into those that grip with hydraulic or pneumatic pressure, and those that grip with spring force and use hydraulic or pneumatic pressure for release action.

The former method has the advantage of being able to obtain a constant strong gripping force even if there are variations in diameter, but the rotating chuck and the hydraulic power source must be connected with a rotary valve, and from the gap between the rotary valve The problem of recovering leaked oil,
There is a problem with heat generation in the cylinder section and rotary valve section.

Furthermore, with this method, especially when the chuck diameter becomes large, a large amount of leakage oil is generated, requiring a large-scale oil recovery device and hydraulic power source.Also, the circumferential speed of the rotary valve section increases, resulting in a large amount of heat generation. It becomes inappropriate. The latter method does not have problems with oil recovery or heat generation, but the gripping force fluctuates when the diameter of the workpiece varies, and a large gripping force cannot be obtained with a workpiece that requires a large stroke of the jaw. There is a point.

The chuck of the present invention solves the above-mentioned problems of the conventional chuck, and its basic idea is to use fluid pressure to move the long distance in the radial direction until the jaws touch the outer peripheral surface of the workpiece. This is done using a cylinder device, and after the pawl lightly contacts the outer peripheral surface of the workpiece, the pawl is strongly tightened by a powerful spring. Therefore, the strong spring that ultimately presses the claw against the workpiece only needs to have a restoring amount that moves the claw a small distance in the radial direction after the claw lightly touches the outer peripheral surface of the workpiece. Since the claws can be pressed at a small amount of restoring, the structure provides a strong and constant gripping force even if the diameter of the workpiece varies.

In addition, fluid pressure is used only when lightly applying the claws to the outer peripheral surface of the workpiece and when releasing the claws against the spring force, and is not used while the spindle is rotating, so leakage fluid can be recovered. No issues or heat generation issues. The specific structure of the chuck of the present invention includes a plurality of claws provided on the chuck body so as to be movable in the radial direction, and the claws move radially inward by movement in the axial direction of the main shaft until they contact the outer peripheral surface of the workpiece. a first means (first wedge body) of the same number as the number of claws that are movable in the radial direction, and a first fluid pressure cylinder device that moves the first means in the direction of the main shaft axis. , after the pawl has come into contact with the outer peripheral surface of the workpiece, a second means (second means) for strongly pressing the pawl against the workpiece via the first means (first wedge body) by movement in the direction of the spindle axis; a wedge body), a counter that biases the second means (second wedge body) in the direction of the spindle axis and in a direction to press the pawl against the workpiece, and the second means (second wedge body). and a second fluid pressure cylinder device that moves the cylinder in the direction of the main shaft axis in a direction that releases the pressing force of the pawl against the spring force.

Therefore, the chuck of the present invention can be applied not only to a normal self-centering chuck, but also by providing the same number of first fluid pressure cylinder devices as the number of jaws for driving the first means (first wedge body). It can also be used as a so-called compensating chuck to reliably and strongly grip cast and forged products with uneven thickness and uneven attachment methods, such as pipe materials with uneven thickness. A wide range of uses can be expected.

Embodiments of the chuck of the present invention will be described in detail below with reference to the drawings.

Figures 1 and 2 show a first embodiment in which the present invention is applied to a hollow type compensating chuck, which is particularly suitable for reliably gripping long pipe materials of large diameter. It is.

An end cover 3 is bolted to the front end flange portion 2A of the main shaft 2 rotatably mounted on the housing 1, and a cylindrical chuck body 4 is bolted so as to protrude from the front side of the end cover 3. . A front cover 5 for guiding claws and a wedge body, which will be described later, is bolted to the front end surface of the chuck body 4, and a small diameter cylindrical sleeve 6 is sandwiched between the front cover 5 and the end cover 3. It is rare. The cylindrical space formed between the sleeve 6 and the chuck body 4 forms a second cylinder 7, and a cylindrical second piston 8 is disposed in the second cylinder 7 in the main axis direction. It is slidably inserted. The second piston 8 has the same number (4) of first cylinders 9 as the claws formed at 90-degree intervals parallel to the main shaft axis, and a first piston 10 slides into each of the first cylinders 9. Possibly inducted. Boat 1 formed on chuck body 4
1A, 1.1B, and 11C communicate with the rear cylinder chamber of the second cylinder 7, the rear cylinder chamber of the first cylinder 9, and the front cylinder chamber of the first cylinder 9, respectively.

a cylindrical bracket 12 extending forward from the housing 1;
, boats 13A, 13B, and 13C are formed, and when pressure fluid is supplied, the boats 11A, 11
It forms a rotary valve that communicates with B and 11C.
A mandrel 15A, 15B is inserted into four holes 14 drilled in the front cover 5 at 90-degree intervals parallel to the main shaft axis, and a large number of disc springs 16 are stacked on the mandrels 15A, 15B.

The mandrels 15A and 15B are connected by a screw 17 so as to be able to move slightly in the axial direction, and the right end of the mandrel 15B is stopped by a cover 18. Therefore, the disc spring 16 braces the mandrels 15A, 15B between the cover 18 and the front end surface of the second piston 8, and applies a leftward biasing force to the second piston 8. Into the four guide grooves 19 formed in the front cover 5 at 90 degree intervals in the radial direction, claws 20 each having a rectangular cross section are inserted so that they can be inserted only in the radial direction. Pads 21, which can be replaced depending on the size of the diameter, are secured with bolts. The front and rear surfaces of the claw 20 are guided by the front surfaces of the front cover 5 and sleeve 6. A mirror inclined surface 20A is formed on the lower surface of the claw 20 at a certain angle (15 degrees in the embodiment of the present invention) with respect to the main shaft axis. A first wedge body 22 is inserted into the guide groove 19 so as to be slidable in the axial direction and radial direction of the main shaft. movably joined. Moreover, the T-shaped protrusion 23 on the upper surface of the first wedge body 22 is slidably inserted into the T-shaped register 24 of the claw 20. The second piston 8 described above extends to near the front end of the chuck body 4 and forms a second wedge body 25.

The second wedge body 25 is formed with inclined surfaces (5 degrees in the embodiment of the present invention) 25A having the width of the first wedge body 22 at 90-degree intervals. It is slidably joined to the inclined surface 22B. Moreover, the T-shaped protrusion 26A at the tip of the pin 26, which is driven in the radial direction from the outer periphery of the second wedge body 25 and is prevented from coming off with a set screw, is attached to the first wedge body 25.
The first wedge body 22 is slidably inserted into the T-shaped groove 27 formed on the lower surface of the wedge body 22, and the first wedge body 22 is slidably inserted into the T-shaped groove 27 formed on the lower surface of the wedge body 22.
This prevents them from leaving 5. The first piston 10 and the first wedge body 22 are provided with through holes 28 and 29 parallel to the main shaft axis, respectively, and steel balls 30A and 3 are provided at both ends.
A connecting rod 31 into which 0B is screwed is inserted.

Joint surface between steel ball 30A and first piston 10 and steel ball 3
The joint surface between 0B and the first wedge body 22 is formed into a conical shape (see FIG. 5), and compensates for the misalignment of the axes of the through holes 28 and 29. Therefore, when the first piston 10 moves to the left in parallel with the spindle axis and pulls the first wedge body 22 to the left, the first wedge body 22 moves to the 5-degree corner of the second wedge body 25. It becomes possible to move along the slope 25A. Further, the steel balls 30A and 30B are connected to the first piston 1.
0 and the first wedge body 22
, 32B are also formed into a conical shape, so they move together even when moving to the right. Next, the operation of the first embodiment of the present invention described above will be explained. In the initial state, pressure fluid is supplied to the boats 11A and 11B, and the boat 11C is connected to the tank side. This state is shown in FIG. 1, where the four first pistons 10 and the second pistons 8 are at the forward end, and the four claws 20 are all fully opened.
After the workpiece is inserted into the chuck, supply pressure fluid to the boat 11C and connect the boat 118 to the tank side (
(While pressure fluid is being supplied to the boat 11A), all four first pistons 10 move to the left, and as the first wedge body 22 moves to the left, all four pawls 20 close. Since the amount of protrusion of the pawl 20 when it hits the outer peripheral surface of the workpiece varies depending on the diameter variation and eccentricity of the workpiece, the stopping position pupils of the first piston 10 and the first wedge body 22 differ depending on each pawl. Grasp the work easily with 4 claws.
Next, due to the time-up signal of the timer, port 11A
When connected to the tank side, the second piston 8 is connected to the disc spring 1
It moves slightly to the left due to the restoring force of 6, and moves the second wedge body 25 to the left by the same amount.

Therefore, the four first wedge bodies 22 simultaneously move a small amount inward in the radial direction, strongly pressing the four claws 20 against the outer peripheral surface of the workpiece, and gripping the workpiece. The restoring amount of the disc spring 16 is only a small amount, just enough to tighten it strongly after the pawl 20 lightly touches the outer circumferential surface of the workpiece, so the strong force of the disc spring 16 can be used, and the disc when tightening strongly can be used. Ne1
6 has a constant amount of restoring, so you can always grasp it with a constant grasping force. Of course, when rotating the main shaft 2, the boat 11C is also connected to the tank side, and there is no need to supply any fluid pressure. In addition, the wedge angle of the first wedge body 22 is 10 degrees in the embodiment, which is much smaller than the sum of the friction angles acting on both sides of the wedge, so even when the claws 20 are strongly tightened, the rotation of the main shaft 2 Even during cutting, the first wedge body 22 never returns. After the machining is completed, if pressure fluid is supplied to the boats 11A and 11B, the second piston 8 moves forward and the space between the second wedge body 25 and the four first wedge bodies 22 becomes slightly loose. , the first wedge body 22 moves forward and the claw 20
is opened, and the workpiece grasping operation is completed. Figure 6 shows claw 2
0 and a modification of the first wedge body 22,
When first pressing the claw 20 lightly against the outer peripheral surface of the workpiece,
By increasing the grasping stroke of the claws 20 in the radial direction, the stroke of the first wedge body 22 in the axial direction can be made small, and the grasping speed of the claws 20 increases.

That is, the large slope portion 33A, which connects the upper surface of the first wedge body 22 and the lower surface of the claw 20
33B and portions 34A and 34B with small obliques, a slight movement of the first wedge body 22 in the direction of the main shaft axis first causes the pawl 20 to move a large stroke in the radial direction, and then the portions with small obliques Since the portions 34B and 34A are joined, the first wedge body 22 will not return even if the main shaft is rotated by strongly tightening the second wedge body 25. 3 and 4 show a second embodiment in which the present invention is applied to a hollow-type self-centering chuck, and FIG.
The basic difference from the first embodiment is that the claw 2 in the first embodiment is
The first piston 10 that lightly presses 0 first is the pawl 20
In contrast, in the second embodiment, the four pawls 20 are pressed in common by one first piston.

The same structural parts as in the first embodiment are indicated by the same numbers, and only the structurally different parts will be explained here.

A cylindrical (doughnut-shaped) first cylinder 35 is formed in the second piston 8, and a cylindrical (doughnut-shaped) first piston is movable in the main axis direction. 36 has been inserted. The first piston 36 and the first wedge body 22 each have steel balls 30A and 30B at both ends.
are connected by a connecting thread 31 which is screwed in. The structure of other parts is completely the same as the first embodiment.
After the workpiece is inserted into the chuck, if pressure fluid is supplied to the boat 11C and the boat 11B is assisted to the tank side,
The first piston 36 moves to the left, and the four first wedge bodies 22 simultaneously move to the left, closing the four pawls 20 simultaneously.

After the claw 20 lightly hits the outer peripheral surface of the workpiece, when the boat 11A is connected to the tank side due to the time-up signal from the timer, the second piston 8 moves slightly to the left due to the restoring force of the disc spring 16. Then, as in the first embodiment, 4
The workpiece is grasped by strongly pressing the claws 20 against the outer peripheral surface of the workpiece. Next, we will discuss the third embodiment in which the present invention is applied to a hollow-type compensating chuck.
This will be explained with reference to FIGS.

The basic difference between the first embodiment and the third embodiment is that the second embodiment
A wedge body is installed for each pawl 20, and is movable in the radial direction relative to the second piston 8,
The point is that the vertical mounting reaction force generated in the second wedge body during vertical mounting is received by the chuck body 4 side. That is, one wedge body 37 is inserted into each of the four guide grooves 19 formed semi-universally at 90 degree intervals in the front cover 5 so as to be slidable in the main shaft axis direction and radial direction.

The upper surface 37A of the first wedge body 3 forms a head slope that meets the inner slope 20A of the lower surface of the claw 20, and the lower surface 37B is a surface parallel to the main axis. The T-shaped protrusion 10A at the tip of the first piston 10 is inserted into the T-slot 38 of the first wedge body 37, allowing the first wedge body 37 to move slightly in the radial direction. Four cylinders 39 are inserted at 90 degree intervals through the chuck body 4 and the second piston 8 in the radial direction, and screws are formed on the outer periphery to adjust the radial position of the cap 40'. .

The cylinder 39' has a guide groove 4 parallel to the main shaft axis and having a rectangular cross section.
1 force is formed, and the guide groove 41 has a second
The wedge bodies 43 are stacked and inserted. A plurality of caged rollers 44 are arranged on the upper and lower surfaces of the second wedge body 42, and the front and rear surfaces of the second wedge body 42 are sandwiched between the second piston 8'. moreover,
Since the front and rear surfaces of the third wedge body 43 are embedded in the front cover 5, it can slide only in the radial direction, and the upper surface 43A parallel to the main axis is connected to the first wedge body 37.
It is in contact with the lower surface 37B of. Below the column 39 is a third
A third piston 46 is inserted into the cylinder 45 in a radial direction. The upper cylinder chamber of the third cylinder 45 is connected to the boat 11A through a passage 47. Additionally, a spring 48 biases the third piston 46 radially inward. On the underside of the first wedge 37,
Three serrated notches 49 are formed, and four conical tip pins 50 that fit into the notches 49 are inserted into the column 39 at slightly different pitches so as to be movable in the radial direction. The hinges 50 are each biased radially inward by a spring 51, and the rear end of the pin 50 passes through the third piton 46, and a nut is installed at the tip.
While pressure fluid is being supplied to the upper cylinder chamber of the third cylinder 45, the pin 50 is retracted as shown in the figure and does not prevent the movement of the first wedge body 37. Next, the operation of the third embodiment of the present invention will be described. Similar to the first embodiment, in the initial state, pressure fluid is supplied to the boats 11A and 11B, and the boat 11C is connected to the tank side.

This state is shown in FIGS. 7 and 8, where the four first pistons 1
0 and the second piston 8 are at the forward end, and all four pawls 20 are fully open. Also, port 11
Since pressurized fluid is being supplied from A to the upper syringing chamber of the third cylinder 45 through the passage 47, the pins 50 are all retracted. After the workpiece is inserted into the chuck, if pressure fluid is supplied to the boat 11C and the boat 11B is connected to the tank side, all four first pistons 10 move to the left and the first wedge As the body 37 moves to the left, all four claws 20 close. Since the amount of protrusion of the pawl 20 when it hits the outer peripheral surface of the workpiece varies depending on the workpiece diameter variation and eccentricity, the stopping positions of the first piston 10 and the first wedge body 37 differ depending on each pawl, and there are The claws 20 lightly grip the workpiece. When the boat 11A is connected to the tank side by the time-up signal of the timer,
The third piston 46 moves forward due to the biasing force of the spring 48, and some of the pins 50 jump into the notch 49 due to the biasing force of the spring 51, thereby preventing movement of the first wedge body 37 in the main shaft axis direction.

At the same time, the second piston 8 moves slightly to the left due to the restoring force of the disc spring 16, and simultaneously moves the four second wedge bodies 42 to the left by the same amount. Therefore, the four third wedge bodies 43 simultaneously move inward in the radial direction by a small amount, strongly pressing the claws 20 against the outer peripheral surface of the workpiece via the first wedge bodies 37, and gripping the workpiece. The reaction force when grasping the workpiece is as follows: the lower surface 37B of the first wedge body 37 → the upper surface 43A of the third wedge body 43 → the roller 44 on the upper surface of the second wedge body 42 → the roller 44 on the lower surface of the second wedge body 42 →It is transmitted to the chuck body 4 via the cylinder 39. After the processing is completed, as in the first embodiment, the boats 11A, 118
When pressure fluid is supplied to , the third piston 46 moves back to remove the pin 50 from the notch 49 , and then the second piston 8 moves forward to remove the second wedge body 42 and the third wedge body 43 . , and after the distance between the third wedge body 43 and the first wedge body 37 is slightly loosened, the first wedge body 37 moves forward to open the claws 20, and the workpiece gripping operation is completed.

In the above-described embodiment of the present invention, the case where there are four claws has been described, but the number of claws can be arbitrarily selected to be four or more or four or less, as required. As described above, the present invention is not limited to the configurations shown in the embodiments, and modifications are expected without departing from the technical idea of the present invention as described in the claims.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the chuck of the present invention, in which FIG. 1 is a longitudinal sectional view, FIG. 2 is a partially sectional front view, and FIGS. 3 and 4 are main views. A second embodiment of the chuck of the invention is shown, FIG. 3 is a longitudinal sectional view, FIG. 4 is a partially sectional front view, and FIG. 5 is a joint between the connecting rod and the first wedge body. FIG. 6 is an enlarged sectional view, FIG. 6 is a perspective view showing a modified example of the inclined surfaces of the claw and the first wedge body, FIGS. 7 and 8 show a third embodiment of the chuck of the present invention, and FIG. is a longitudinal section,
FIG. 8 is a sectional view taken along the line AA in FIG. 7. In the figure, 1...Housing, 2...Main shaft, 4...Chuck body, 5...Front cover, 7...Second cylinder, 8...Second piston, 9...First cylinder, 10... ...first piston, 16... disk spring,
19...Guide groove, 20...Claw, 22...
...First wedge body, 25... Second wedge body, 35... First cylinder, 36... First piston, 37... First wedge body, 39... Cylinder, 42...
...Second wedge body, 43...Third wedge body, 45...Third cylinder, 46...Third piston. Figure 1 Figure 6 Figure Z Figure 4 Figure 5 Figure 3 Figure 7 Figure 8

Claims (1)

[Claims] 1 A chuck body, a plurality of pawls provided on the chuck body so as to be slidable back and forth in the radial direction, and a chuck body that engages with the plurality of pawls, is movable within a plane including the central axis of the chuck body, and is movable by movement in the axial direction. a plurality of first wedge bodies that are movable radially inward until each claw lightly contacts the outer periphery of the work; and a first fluid pressure that moves the first wedge bodies in the axial direction and is set to a low pressure. a cylinder device; a movable connection means that connects the piston of the first fluid pressure cylinder device and the plurality of first wedge bodies to transmit movement;
a second wedge body that engages with the plurality of first wedge bodies, is movable in the axial direction, and is capable of firmly pressing each claw against the workpiece after the plurality of claws lightly contact the outer periphery of the workpiece; , a spring that urges the second wedge body in the axial direction and in a direction that firmly presses each claw against the workpiece;
a second fluid pressure cylinder device which includes a fluid pressure cylinder device and is set to a high pressure by moving the second wedge body in the axial direction in a direction that releases the pressing force of the claw against the spring force; A chuck consisting of.