JPH0551516U - Chuck device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a chucking device capable of preventing the object to be cut off and the like and having a high cutting speed with a simple structure. In the chuck device according to the present invention, a plurality of gripping claws 4 are arranged on a front surface of a chuck body 3 at intervals in a circumferential direction, and the gripping claws 4 are moved in a radial direction to cut an object to be cut. 2 for fixing the centrifugal force 5 between the gripping claws 4 of the chuck body 3 via the arm 7 to prevent the centrifugal force generated when the chuck body 3 rotates. By operating the centrifugal weight 5, the auxiliary clamp 6 is configured to move in the tightening direction of the workpiece 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a chuck device used for fixing an object to be cut (work piece), particularly an object that is thin and cannot hold a large gripping force of the chuck.

[0002]

[Prior Art]

 Conventionally, a chuck device 51 as shown in FIG. 4, for example, is attached to a spindle of a machine tool such as a lathe. The chuck device 51 is provided with three gripping claws 53 arranged at equal intervals on the front surface of the chuck body 52. By sliding these gripping claws 53 in the semi-radial direction, the workpiece 54 is cut. It is configured to be tightened and fixed and to be given a rotational movement.

[0003]

[Problems to be solved by the device]

 However, in the above-described conventional chuck device 51, when the centrifugal force increases as the number of rotations increases, the chuck gripping force on the workpiece 54 decreases by the area D, as shown in FIG. In particular, in the case of a thin workpiece 54 that may be tightened with a small gripping force, the workpiece 54 may drop or slip due to cutting resistance during lathe machining. Therefore, in the conventional chuck device 51, the cutting speed of the thin-walled work 54 cannot be increased so much that the machining operation takes a lot of time.

The present invention has been made in view of such an actual situation, and an object thereof is a chuck device capable of preventing falling of a work piece with a simple structure and increasing a cutting speed. To provide.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems of the prior art, in the present invention, a plurality of gripping claws are arranged on the front surface of the chuck body at intervals in the circumferential direction, and these gripping claws are moved in the radial direction. In the chuck device that fixes the workpiece by means of auxiliary clamps that connect centrifugal weights via arms between the gripping claws of the chuck body, the centrifugal force generated when the chuck body rotates By operating the centrifugal weight, the auxiliary clamp is configured to move in the tightening direction of the workpiece.

[0006]

[Work]

 In the chuck device of the present invention, the auxiliary clamp is moved in the tightening direction of the workpiece by the centrifugal weight that operates when the chuck body rotates, so that the workpiece is assisted in addition to the normal gripping action of the gripping jaws. It is also clamped by the clamp, and even if the gripping force decreases as the number of rotations increases, the gripping force of the auxiliary clamp for the workpiece is increased and complemented.

[0007]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIGS. 1 to 3 show an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a chuck device attached to the tip of a spindle (not shown) of a rotary machine tool such as a lathe. The device 1 is used for fixing a work 2 to be machined during lathe machining and giving a rotary motion to the work 2.

The chuck device 1 includes a chuck body 3 formed in a cylindrical shape, and three gripping bodies arranged on the front end surface of the chuck body 3 at equal intervals (120 ° intervals) along the circumferential direction. The claw 4 is provided with a centrifugal weight 5 and an auxiliary clamp 6 provided on the chuck body 3 located between the gripping claws 4.

The gripping claw 4 is a rectangular parallelepiped block, and the front end portion is formed as an arc-shaped work gripping surface 4 a corresponding to the outer peripheral surface of the workpiece 2, and the work gripping surface 4 a of the chuck body 3 is formed. It is located on the inner circumference side. Further, the grip claw 4 is configured to be movable in the radial direction by a drive mechanism (not shown) built in the chuck body 3. Then, the three gripping claws 4 are moved by the same dimension toward the center of the chuck body 3 and the outer peripheral surface of the work 2 is clamped by the work gripping surface 4a to grip the work 2. Then it is fixed.

The centrifugal weight 5 and the auxiliary clamp 6 are connected via an arm 7 formed in a dogleg shape, and are arranged side by side along the circumferential direction when the rotation of the chuck body 3 is stopped. The centrifugal weight 5 and the auxiliary clamp 6 are disposed apart from the front end surface of the chuck body 3 and are not fixedly supported, but the intermediate portion of the arm 7 can be rotated to the chuck body 3 by the fixing pin 8. Supported by. For this reason, the base end portion of the fixing pin 8 is implanted in the chuck body 3, and the holding ring 9 for preventing the arm 7 from being pulled out is fitted to the tip portion protruding from the front end surface of the chuck body 3. ing.

On the other hand, the center of the centrifugal weight 5 and one end of the arm 7 are integrally connected to each other by a weight connecting pin 10, and the upper part of the auxiliary clamp 6 and the other end of the arm 7 are clamp-connected. The pins 11 are integrally connected to each other. Since the centrifugal weight 5 operates in the direction of arrow a in FIG. 1 due to the centrifugal force generated by the counterclockwise rotation of the chuck body 3, the centrifugal weight 5 should be positioned on the opposite side of the auxiliary clamp 6 from the rotational direction. It is arranged so that the auxiliary clamp 6 moves in the direction of arrow b in FIG. The lower surface of the auxiliary clamp 6 is formed as a clamp surface that presses the outer peripheral surface of the work 2 to be cut.

That is, the mass of the centrifugal weight 5 (including the mass of the arm 7) is Mi, the mass of the auxiliary clamp 6 (including the mass of the arm 7) is Mc, the connecting pin 10 of the centrifugal weight 5 and the fixing pin of the arm 7. 8 is Li and the distance between the connecting pin 11 of the auxiliary clamp 6 and the fixing pin 8 of the arm 7 is Lc, the clamping force Fc is obtained from the general formula of centrifugal force F = Mrω ^2. , R is constant, it occurs by deciding each value so that Fc> Mi.Li-Mc.Lc is established. Here, r represents the radius of gyration, and ω represents the angular velocity.

To lathe the workpiece 2 using the chuck device 1 of this embodiment, first, the chuck body 3 is attached to a spindle of a lathe (not shown). Next, the workpiece 2 is placed at a position surrounded by the workpiece gripping surface 4a of the three gripping nails 4, and the gripping nails 4 are moved toward the center of the chuck body 3 to move the workpiece 2 The outer peripheral surface of the is gripped and fixed by the work gripping surface 4a. At this time, since the work 2 has a thin pipe shape, the gripping force needs to be smaller than that of a solid or thick work.

When the chuck body 3 starts rotating counterclockwise in this state, a centrifugal force acts on the entire centrifugal weight 5, the auxiliary clamp 6 and the arm 7, and the centrifugal weight 5 operates in the direction of arrow a in FIG. Therefore, by making the distance between the weight connecting pin 10 and the fixing pin 8 longer than the distance between the fixing pin 8 and the clamp connecting pin 11, and by making the weight of the centrifugal weight 5 heavier than that of the auxiliary clamp 6, the auxiliary clamp 6 is attached. The centripetal force acts in the direction of arrow b, and the work 2 is clamped not only by the gripping pawl 4 but also by the auxiliary clamp 6.

Therefore, according to the present embodiment, even if the gripping force of the gripping claw 4 on the workpiece 2 decreases due to centrifugal force as the number of rotations of the chuck device 1 increases, the gripping force of the auxiliary clamp 6 is reduced. Therefore, the reduction of the gripping force of the chuck device 1 as a whole can be sufficiently compensated, and the workpiece 2 can be cut while being firmly fixed even at high speed rotation.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications and changes can be made based on the technical idea of the present invention. It

For example, the centrifugal weight 5 and the auxiliary clamp 6 in the above-described embodiments may be configured to be replaceable, whereby the gripping force of the auxiliary clamp 6 is increased or decreased, or the machining diameter of the workpiece 2 is changed. Can respond to changes.

[0019]

[Effect of the device]

 As described above, the chuck device according to the present invention is provided with a plurality of gripping claws on the front surface of the chuck body and the auxiliary clamp formed by connecting the centrifugal weight with the arm, and the centrifugal force generated when the chuck body rotates. The auxiliary clamp is configured to move in the tightening direction of the workpiece by operating the centrifugal weight by using the. Even if the workability decreases, the gripping force of the auxiliary clamp increases, so that the work piece can be firmly fixed, and even when cutting a thin work piece, the work piece may drop or slip. It can be surely prevented. Therefore, by using the chuck device of the present invention, the cutting speed of the object to be cut can be increased, so that the cycle time of the cutting work can be greatly shortened and the work efficiency can be improved. Moreover, since the auxiliary clamp mechanism of the present invention does not use any special power and uses only the centrifugal force generated when the chuck body rotates, the structure is simple and the cost is not increased. , Economically advantageous.

[Brief description of drawings]

FIG. 1 is a front view showing a chuck device according to an embodiment of the present invention.

FIG. 2 is a side view showing the vicinity of an auxiliary clamp of the chuck device.

FIG. 3 is a plan view showing a cross section of a state in which a centrifugal weight and an auxiliary clamp of the chuck device are connected via an arm.

FIG. 4 is a front view showing a conventional chuck device.

FIG. 5 is a characteristic diagram showing a relationship between a rotation speed and a chuck gripping force in a conventional chuck device.

[Explanation of symbols]

 1 Chuck Device 2 Workpiece 3 Chuck Body 4 Grip Claw 5 Centrifugal Weight 6 Auxiliary Clamp 7 Arm 8 Fixing Pin 9 Holding Ring 10 Weight Connecting Pin 11 Clamp Connecting Pin

Claims (1)

[Scope of utility model registration request] 1. A chuck device for fixing a workpiece by arranging a plurality of gripping claws on a front surface of a chuck body at intervals in a circumferential direction and moving the gripping claws in a radial direction. Auxiliary clamps, which connect centrifugal weights via arms to each other between the gripping claws of the main body, are provided, and the centrifugal weights are operated by the centrifugal force generated when the chuck body rotates, so that the auxiliary clamps are covered. A chuck device characterized in that it is configured to move in the tightening direction of a cut object.