KR20200108998A - A head stock of a lathe having a function of adjusting chucking force - Google Patents

Abstract

The present invention relates to a headstock of a lathe for performing machining while rotating a workpiece by rotation of a spindle. The headstock of a lathe of the present invention comprises: a collet chuck which can shrink and expand in a radial direction of the workpiece by the movement of the spindle in the direction of a rotation axis, and chuck the workpiece by applying a pressing force to the workpiece by contracting; a collet sleeve having a surface surrounding the collet chuck to provide a reaction force contracting in the radial direction to the collet chuck, and fixed to the spindle; a movable member having a collet chuck coupled to a front end thereof, extending along the rotation axis of the spindle, and movable in the rotation axis direction of the spindle to move the collet chuck in the rotation axis direction of the spindle; an unchucking force mechanism which presses the movable member in a first direction of the rotation axis direction of the spindle to provide an unchucking force to release the collet chuck from a chucking state with respect to the workpiece; and a chucking mechanism for applying a chucking force for the collet chuck to chuck the workpiece by pressing the movable member in a second direction opposite to the first direction.

Description

A headstock of a lathe with a chucking force adjustment function {A HEAD STOCK OF A LATHE HAVING A FUNCTION OF ADJUSTING CHUCKING FORCE}

The present invention relates to a lathe headstock having a chucking force adjustment function, and in particular, to a pull-down lathe headstock capable of adjusting the chucking force.

A collet chuck is used to fix the workpiece on the main shaft of the lathe to be machined while fixing and rotating the elongated workpiece. While expanding and contracting, the collet chuck presses the end of the workpiece inserted inside the collet chuck in the radial direction to support it.

As a lathe according to the prior art in which such a collet chuck is used, there is a chucking device for an automatic lathe disclosed in Registered Utility Model Publication No. 20-0371991 (Document 1).

The chucking device of an automatic lathe of Document 1 will be described with reference to FIG. 1. 1 is a cross-sectional view schematically showing a cross-section of a shelf according to the prior art.

The lathe includes a headstock 105 fixedly installed, a spindle 103 rotating inside the headstock 105, a spindle motor 107 rotating the spindle, and between the spindle 103 and the headstock 105. A plurality of ball bearings (108a, 108b) that rotatably support the spindle (103), the collet chuck (101) for chucking the workpiece while rotating together with the spindle (103), and the outer surface of the collet chuck (101) with an inclined contact The collet sleeve 104 contracts or expands the collet chuck 101 by operating backward and forward, the push pipe 106 for moving the collet sleeve 104 forward and backward, and the collet sleeve 104 disposed on one side of the collet chuck 101 A compression spring 102 for expanding the collet chuck 101 by pushing 104, a toggle 109 for moving the push pipe 106 forward and backward, a slide sleeve 113 for rotating the toggle 109, and a slide sleeve 113 ) And an air cylinder 120 that reciprocates the chuck lever 116 and reciprocates the chuck lever 116.

When machining a workpiece (not shown) on a lathe, the spindle motor 107 formed inside the headstock 105 rotates and the spindle 103, the push pipe 106, and the collet sleeve ( 104), and the collet chuck 101 and the like rotate together.

In the collet sleeve 104, one side is coupled to the push pipe 106, and on the other side, the inner inclined surface contacts the outer surface of the collet chuck 101, and the collet chuck 101 expands or contracts by its forward and backward operation. Chuck or unchuck.

Specifically, when the collet sleeve 104 moves toward the collet chuck 101, the collet chuck 101 contracts radially inward and presses and chucks the end of the workpiece disposed therein, and on the contrary, the collet sleeve 104 When) moves backward, the collet chuck 101 is expanded and the chucking of the workpiece is released.

The push pipe 106 moves forward by the action of the toggle 109 and serves to push the collet sleeve 104 forward.

The push pipe 106 is advanced in the direction of the collet chuck 101 by the rotation operation of the toggle 109, and the toggle 109 rotates by the operation of the slide sleeve 113. The slide sleeve 113 is operated forward and backward by a chuck lever 116 that rotates around a hinge point 118 by an air cylinder 119.

One end of the chuck lever 116 is coupled to the slide sleeve 113, the other end is coupled to the piston rod 121 of the air cylinder 120, and the chuck lever 116 uses the hinge point 118 as a fixed point. It is rotated by the air cylinder 119.

When the piston rod 121 of the air cylinder 120 is expanded, the chuck lever 116 pushes the slide sleeve 113 to the front of the toggle 109, and the toggle 109 pushes the push pipe 106, and the collet chuck 101 ) Is in the chucking state.

Conversely, when the piston rod 121 of the air cylinder 120 is contracted, the chuck lever 116 pushes the slide sleeve 113 to the rear of the toggle 19, so that the toggle 19 pushes the push pipe 106 By pulling, the collet chuck 101 is in an unchucked state.

Compressed air is supplied to the air cylinder 120 in both directions. When chucking is performed, compressed air is supplied to a chucking line (not shown), and when chucking is released, compressed air is supplied to an unchucking line (not shown).

The lathe headstock having the configuration as described in Document 1 as described above has the advantage that the collet chuck does not move in the longitudinal direction when chucking the workpiece, but the collet sleeve is movable for chucking/unchucking the collet chuck, so the rotation axis of the spindle There is a problem in that it is difficult to match the concentricity of the collet sleeve, so that high processing precision cannot be obtained.

To solve this problem, a pull-down lathe headstock is used in which the collet sleeve is fixed in the longitudinal direction, the collet chuck is pulled against the collet sleeve (PULL DOWN OR PULL BACK) and chucked, and the collet chuck is pushed to unchuck. Has become.

The pull-down lathe headstock is to provide a rotary actuator such as a rotary cylinder, and convert the rotation of the rotary cylinder into a translational motion of the collet chuck so that chucking and unchucking operations are performed.To this end, the lathe main axis as in the invention of Document 1 Since the configuration of the spindle of the base must be drastically changed to attach a rotary cylinder and a configuration for converting the rotational movement into a translational movement is provided, there is a problem that the manufacturing cost of the headstock is considerably high and the manufacturing process is complicated.

Document 1: Registered Utility Model Publication No. 20-0371991 Document 2: Patent Publication No. 10-1157324

The present invention is to provide a mechanism for pushing and pulling a collet chuck with a simple configuration in a pull-down lathe headstock having a configuration of chucking and unchucking a workpiece by pulling and pushing a collet chuck in consideration of the problems of the prior art described above.

In particular, the present invention is to provide a lathe headstock having a configuration capable of applying a pull-down method without significantly changing the configuration of the lathe headstock having the same configuration as in Document 1.

In addition, as the pull-down type lathe headstock of the present invention, it is intended to provide a lathe headstock having a configuration in which the chucking force for a workpiece can be easily adjusted to a fine level.

The above-described problem of the present invention is achieved by the present invention relating to a headstock of a lathe for machining while rotating a workpiece by rotation of a spindle.

The headstock of the lathe according to the present invention,

A collet chuck capable of contracting and expanding in the radial direction of the workpiece by moving the spindle in the direction of the rotation axis, and chucking the workpiece by applying a pressing force to the workpiece by contracting; A collet sleeve having a surface surrounding the collet chuck, providing a reaction force contracting in the radial direction to the collet chuck, and being fixed to the spindle; A movable member having a collet chuck coupled to the tip end thereof, extending along a rotation axis of the spindle and movable in a rotation axis direction of the spindle to move the collet chuck in the rotation axis direction of the spindle; An unchucking force mechanism that presses the movable member in a first direction in a direction of a rotation axis of the spindle to provide an unchucking force to release the collet chuck from a chucking state with respect to the workpiece; And a chucking mechanism for pressing the movable member in a second direction opposite to the first direction to apply a chucking force for the collet chuck to chuck the workpiece,

The chucking mechanism consists of a spring compressed in the direction of the rotation axis of the spindle, and one end is supported by the spindle and the other end is supported by a movable member, and the amount of compression is adjusted by adjusting the distance between one end supported by the spindle and the other end supported by the movable member. In a state in which the unchucking force by the unchucking mechanism is released, the movable member is pressed in the second direction by compressing the movable member in the second direction by the restoring force, and the unchucking force by the chucking mechanism is the maximum Is greater than the value.

In the lathe headstock of the present invention, the movable member is pressed in the first direction by the unchucking mechanism to expand the collet chuck to insert the workpiece into the collet chuck, and when the unchucking mechanism is released, the spring maintains the compressed state. The collet chuck is contracted by pressing the movable member in the second direction with a restoring force due to compression to chuck the workpiece.

Unchucking is achieved by applying an unchucking force larger than the chucking force due to the restoring force of the spring by the chucking mechanism to the movable member, and chucking is achieved by removing the unchucking force by the unchucking mechanism.

Even in a state in which the unchucking force is not applied, the spring constituting the chucking mechanism maintains a compressed state, and the unchucking is achieved by pressing the movable member in the first direction by surpassing the restoring force by compression of the spring.

The chucking force is a restoring force applied by a spring to the movable member in a state in which the unchucking force is not applied, and the restoring force of this spring is adjusted by adjusting the distance between the movable member supporting the spring in a compressed state and a support point to the spindle.

As described above, according to the present invention, by adjusting the compression amount in the initial state of the spring, that is, the compression amount in the state in which the unchucking force is not applied, it can be easily adjusted and precisely adjusted, and the unchucking is the maximum value of the chucking force. It can be accomplished by simply applying a force that surpasses it.

Therefore, the lathe headstock having this structure can precisely adjust the chucking force in the pull-down collet chuck, and can be implemented in a simple structure without changing the structure of the spindle to apply a mechanism such as a rotary cylinder.

On the other hand, as an embodiment of the present invention, the spring constituting the chucking mechanism is composed of a plurality of disc springs disposed in contact with each other, and the disc springs are disposed to be penetrated by the movable member to be compressed in the unchucking state and second It can be configured by applying a chucking force to the movable member in the direction.

In this way, by using the disc spring, a structure capable of applying a large chucking force is provided while minimizing additional components for special mounting in a narrow space.

1 is a cross-sectional view showing a lathe headstock according to the prior art.
2 is a plan view showing an unchucking state of a workpiece in a lathe headstock according to an embodiment of the present invention, respectively.
3 is a cross-sectional view taken along line AA in FIG. 2.
FIG. 4 is a cross-sectional view taken along line AA of FIG. 2 and shows a chucking state of a workpiece.

Hereinafter, a configuration and operation of a lathe headstock according to an embodiment of the present invention will be described as specific details for carrying out the present invention with reference to FIGS. 2 to 4.

Other configurations other than the configuration for chucking and unchucking in the lathe headstock according to an embodiment of the present invention can be adopted as it is the configuration of the lathe headstock equipped with a conventional pull-down collet chuck, so the description thereof will be omitted. In the description and drawings, configurations related to chucking and unchucking are mainly shown and described.

First, the configuration of the lathe headstock will be described with reference to FIGS. 2 and 3.

A spindle 1 is rotatably provided in the main shaft of the lathe, and a built-in spindle motor 2 for rotationally driving the spindle 1 is provided around the spindle 1.

A collet chuck assembly 10 that rotates according to the rotation of the spindle 1 and chucks the workpiece is provided. The collet chuck assembly 10 is configured to extend along the rotational axis of the spindle 1 as a whole, and the front end is composed of a collet chuck 11 to chuck a workpiece (not shown) inside by contraction, and the rear end is a spindle It is composed of a movable tube 12 that rotates inside of (1).

The collet sleeve 5 is fixed to the front end of the spindle 1 outside the collet chuck 11. The collet sleeve 5 has an inner surface formed as an inclined surface in contact with the outer surface of the collet chuck 11, so when the collet chuck 11 is pulled to the left in FIG. 2, it contracts and applies a chucking force to the workpiece, and FIG. When pushed to the right, it expands and unchucks the workpiece.

At the rear end of the movable tube 12, a draw pipe 20 is provided as a movable member. The draw pipe 20 is disposed inside the spindle 1 and extends along the axis of rotation. The draw pipe 20 is formed integrally with a front portion 21 having a large diameter and a rear portion 22 having a small diameter.

A toggle sleeve 31 constituting an unchucking mechanism is provided on the rear end side of the front portion 21 of the draw pipe.

The toggle sleeve 31 is disposed in contact with the outer surface of the spindle 1 and rotates like the spindle 1, but can slide in the direction of the rotation axis of the spindle 1, and in the radial direction of the toggle sleeve 31 The shift ring 33 is coupled to the outside through a bearing 32, so that the shift ring 33 performs only linear motion along the axis of rotation of the spindle.

The shift ring 33 receives the movement of the piston rod of the air cylinder 34 shown in FIG. 3 through the lever mechanism 35 to slide the toggle sleeve 31 along the rotation axis B of the spindle.

To the rear of the toggle sleeve 31 in the longitudinal direction, that is, to the opposite side of the collet chuck, the toggle 40 is coupled to the spindle 1 so as to be rotatable about the hinge 41.

The toggle 40 is pressed in a state in contact with the toggle sleeve 31 at one point by a toggle spring (not shown), and at the other point, between the front portion 21 and the rear portion 22 of the draw pipe 20 It is in contact with the chin. A point where the toggle 40 abuts on the toggle sleeve 31 is formed as an inclined surface.

When the toggle sleeve 31 moves to the rear side by the air cylinder 34, the toggle 40 rotates, and accordingly, the draw pipe 20 is pushed forward while rotating the point where the draw pipe 20 abuts.

A flange 52 is supported by the spindle 1 on the rear side of the toggle 40 in the rear portion 22 of the draw pipe, and a plurality of disc springs 51 are arranged as a chucking mechanism at the rear of the flange 52. have.

The disk springs 51 are arranged to be in contact with each other in the rotation axis direction B of the spindle 1 in a state in which a hole is formed at the center side and the rear portion 22 of the draw pipe passes through. A spring collar 53 is disposed at the rear end of the disc spring 51, and a lock nut 54 is fastened to the draw pipe 20 at the rear of the spring collar 53.

Accordingly, in the direction of the rotation axis (B), the disc spring 51 is supported on the spindle 1 by the flange 52 on the front side and the draw pipe through the spring collar 53 and lock nut 54 on the rear side. It is supported by (20).

The adjustment pin 55 protrudes outward from the outer surface of the lock nut 54, and the lock nut 54 is rotated by the adjustment pin 55 to move the lock nut 54 forward or backward. The amount of compression of the disc spring 51 can be adjusted.

The operation of the headstock according to the above configuration will be described.

First, the unchucking state will be described.

When the lever mechanism 35 is operated by the air pressure acting on the air cylinder 34, the toggle sleeve 31 moves backward and the toggle 40 rotates to push the draw pipe 20 forward.

Thereby, the collet chuck assembly 10 moves forward so that the collet chuck 11 is separated from and expanded from the collet sleeve 5 for pressing the collet chuck 11 radially inward from the outer surface, thereby chucking the workpiece. Is expanded.

It will be described with reference to FIG. 4 showing a cross section in a chucking state.

After inserting the workpiece into the collet chuck 11 in the unchucking state shown in Figs. 2 and 3, the chucking operation is performed. The chucking operation consists only of removing and returning the air pressure applied to the air cylinder 34.

When the lock nut 54 is tightened by the adjustment pin 55 while the disc spring 51 is disposed between the spring collar 53 and the flange 52, the spring collar 53 is forward, that is, the collet chuck is disposed. The disc spring 51 is compressed by moving in the same direction.

In this compressed state, when air pressure is supplied to the air cylinder 34 to perform the unchucking operation, the draw pipe 20 moves forward and the disk spring 51 is further compressed. The air pressure supplied to the air cylinder 34 is provided at a pressure capable of providing a force greater than the restoring force of the disc spring 51.

When the chucking operation is executed and the air pressure applied to the air cylinder 34 is removed and the piston rod of the air cylinder returns to its original position, the toggle sleeve 31 also moves forward, and the toggle 40 also rotates backwards before the unchucking state. To return.

In this state, since the force compressing the disc spring 51 is removed, the spring collar 53 is forced to the rear by the restoring force of the disc spring, and the draw pipe 20 is pulled rearward.

In this way, the force of pulling the draw pipe 20 backward is in the initial state, that is, the disc spring 51 is compressed by the operation of tightening the lock nut 54 before the draw pipe 20 moves forward by the unchucking operation. State.

The restoring force due to the compression of the disc spring 51 in the initial state becomes a force that pulls the draw pipe 20 backward and pulls the collet chuck 11, thereby contracting the collet chuck 11 to become a chucking force for the workpiece. Works.

In this state, the workpiece is processed while rotating the spindle 1.

When processing is finished and the workpiece is removed from the collet chuck 11, the above-described unchucking operation is performed.

Meanwhile, the chucking force by the disc spring 51 may vary depending on the number of disc springs, elastic modulus, compression amount, and arrangement form. Thus, it is possible to adjust the chucking force by adjusting these parameters.

In particular, after the disc springs 51 are inserted into the headstock and arranged, the lock nut 54 is pushed forward by the adjustment pin 55 to narrow the distance between the spring collar 53 and the flange 52. When the disc springs 51 are further compressed, the restoring force is increased and the chucking force is increased. Conversely, when the amount of compression of the disc springs 51 is reduced by increasing the distance between the spring collar 53 and the flange 52 by loosening the lock nut 54 backward by the adjustment pin 55, the restoring force is increased. Decreases and the chucking force is lowered.

In this way, by adjusting the lock nut 54 by the adjustment pin 55, the chucking force in the collet chuck 11 can be easily and simply adjusted, and in particular, the chucking force can be precisely adjusted.

In addition, when the chucking force required by the collet chuck 11 exceeds the compression amount adjustment range of the disc spring 51 by adjusting the lock nut 54, the rear side of the headstock is disassembled and the disc spring 51 is removed. It is also possible to further increase the chucking force by additional mounting or changing the arrangement.

The unchucking force applied by the air cylinder 34 is set to a level greater than the maximum chucking force that can be obtained by adjusting the lock nut 54 and adding the disspring 51, so that the unchucking operation is performed by the air cylinder ( 34) can be done smoothly without adjusting the air pressure.

On the other hand, in this embodiment, the draw pipe is Although a plurality of disc springs of the constitution are arranged to constitute a chucking mechanism, a compression coil spring may be disposed between the spring collar and the flange in place of the disc spring.

In addition, in this embodiment, an air cylinder and a toggle mechanism are used as the unchucking mechanism, but instead, a force greater than the maximum chucking force of the adjustable chucking mechanism can be applied as the unchucking force, and the draw pipe is unchucked in the unchucking direction. You can also use other devices that can be pushed.

In the above, the configuration and operation of a preferred embodiment of the present invention has been described. The present invention is not limited to the configuration of these embodiments, and various changes, modifications, and additions of components are possible within the scope described in the claims.

1: spindle 11: collet chuck 20: draw pipe
31: toggle sleeve 40: toggle 51: disc spring
52: flange 53: spring collar 54: lock nut
55: adjustment pin

Claims (5)

As the main shaft of a lathe that is machined while rotating the workpiece by the rotation of the spindle,
A collet chuck capable of contracting and expanding in the radial direction of the workpiece by moving the spindle in the direction of the rotation axis, and chucking the workpiece by applying a pressing force to the workpiece by contracting;
A collet sleeve having a surface surrounding the collet chuck to provide a reaction force contracting in the radial direction to the collet chuck and fixed to the spindle;
A movable member having a collet chuck coupled to the tip end thereof, extending along a rotation axis of the spindle and movable in a rotation axis direction of the spindle to move the collet chuck in the rotation axis direction of the spindle;
An unchucking mechanism for pressing the movable member in a first direction in a direction of a rotational axis of the spindle to provide an unchucking force to release the collet chuck from a chucking state with respect to the workpiece;
A chucking mechanism for applying a chucking force for the collet chuck to chuck the workpiece by pressing the movable member in a second direction opposite to the first direction
Including,
The chucking mechanism consists of a spring compressed in the direction of the rotation axis of the spindle, and one end is supported by the spindle and the other end is supported by a movable member, and the amount of compression is adjusted by adjusting the distance between one end supported by the spindle and the other end supported by the movable member. In a state in which the unchucking force by the unchucking mechanism is released, the movable member is pressed in the second direction by compressing the movable member in the second direction by a predetermined compression amount, and the unchucking force by the unchucking mechanism is the maximum of the chucking force by the chucking mechanism. The headstock of the lathe, which is greater than the value. The method according to claim 1,
The spring of the chucking mechanism is composed of a plurality of disc springs that are disposed in contact with each other, and the disc springs are disposed to be penetrated by the movable member, compressed in the unchucking state, and applying a chucking force to the movable member in the second direction by the restoring force. One, the headstock of the lathe. The method according to claim 2,
The other end of the disc springs is supported by a spring collar fixed to the movable member by varying a position in the longitudinal direction of the movable member, and the chucking force is adjusted according to the position of the spring collar. The method according to claim 2,
The headstock of the lathe is configured to vary the number and arrangement of the disk springs. The method according to any one of claims 1 to 4,
The unchucking mechanism consists of a toggle mechanism that converts a linear motion in a rotation axis direction of a spindle by an actuator into a rotational motion, and an unchucking force is applied to the movable member in a first direction by the rotational motion of the toggle mechanism. Headstock.

Images