JPH0123690Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a power chuck having a chuck pin used in a lathe or the like.

[Conventional technology]

As a power chuck having the chuck pin as described above, Japanese Patent Publication No. 47-26838 and Utility Model Publication No. 57
-There is one described in Publication No. 193304.

In each of these, a plurality of diagonal holes are formed in the vicinity of the periphery of the chuck body that rotates with the main shaft in a manner that spreads out at regular intervals, and a chuck pin is inserted into each diagonal hole so that it can move forward and backward. , providing a support member that engages the rear end of the chuck pin;
This support member is moved forward and backward by a hydraulic cylinder, etc., and a chuck pin that moves back and forth in an oblique direction grasps the outer circumferential surface of a ring-shaped or cylindrical workpiece and fixes it to the chuck body, and the workpiece is rotated. It is used for cutting, etc.

[The problem that the idea attempts to solve]

In the case of the known pin-type power chuck mentioned above, the workpiece must be rotated by simply gripping the outer periphery of the workpiece using the chuck pin, overcoming the strong resistance that occurs during cutting. The outer circumferential surface of the workpiece must be gripped. To do this, it is necessary to forcefully pull the support member connected to the chuck pins rearward using a hydraulic cylinder to forcefully pull each chuck pin rearward.

Each chuck pin is attached to a diagonal hole provided in the chuck body so that it can move forward and backward, so when the tip of the chuck pin grips the workpiece and the rear end of the chuck pin is pulled strongly by the support member, a large bending load is applied to each chuck pin. Moreover, since the chuck pin slides in the diagonal hole in this state, problems arise such as increased wear on the back surface of the chuck pin and the diagonal hole in contact therewith.

Furthermore, when the inner circumferential surface of a workpiece must be machined with high accuracy based on the outer circumferential surface, the workpiece may become distorted, making it impossible to perform high-precision cutting, or the outer circumferential surface may be damaged. cause problems.

Furthermore, the power chuck described in Japanese Utility Model Application Publication No. 52-28791 has a first claw that grips the outer periphery of the workpiece and performs centering, and a second claw that presses the workpiece after centering against the front surface of the chuck. This chuck has two claws, but since the first and second claws are opened and closed by hydraulic cylinders that operate separately in the front and back, the structure and hydraulic circuit for driving the claws are complex. Since the second pawl is rotated by a cam, it is weak in terms of rigidity, making it unsuitable for use as a chuck for medium-sized or large-sized workpieces.

This idea differs from the conventional pin-type power chuck as mentioned above, in that it does not distort the workpiece.
It is an object of the present invention to provide a power chuck which can grip a workpiece accurately and strongly with a simple mechanism without damaging the outer peripheral surface.

[Means to solve the problem]

In order to solve the above problems, this invention includes a first claw that is detachably provided at the front end of the main chuck pin and presses the workpiece against the main body in an oblique direction;
A first support member that engages with the rear end of the main chuck pin and moves axially on the axis of the main body by being coupled to the driving means and has a structure similar to that of the diagonal hole between the main chuck pin and an auxiliary chuck pin that is inserted into a plurality of second diagonal holes so as to be freely retractable; a second pawl that is removably provided at the front end of the auxiliary chuck pin for centering the workpiece; and the auxiliary chuck pin. a second support member that engages with the main body and moves in the axial direction on the central axis of the main body astride the main body and the support member; The second pawl of the auxiliary chuck pin centers the workpiece through the second support member, which is moved by the bias of the spring, and then the drive means operates. The first claw of the main chuck pin grips the workpiece via the first support member that moves at the same speed.

[Effect]

Since this device has the above-mentioned structure, first, the flange side of a cylindrical workpiece having a flange is applied directly to the front surface of the chuck body or to a support ring fixed to the front surface, and then the workpiece is driven by power from a hydraulic cylinder or the like. When the first support member in the main body is retracted by the means, the second support member is also retracted together with the first support member by the spring, and the second claw at the tip of the auxiliary chuck pin first touches the workpiece. Center the workpiece by gripping the outer peripheral surface of the flange of the workpiece with a force that does not distort the workpiece.

Even after the second support member stops retreating in this way, the first support member moves back further and presses the back side of the flange with the first claw at the tip of the main chuck pin, pushing the workpiece to the front side of the support ring, etc. Press firmly to secure.

Also, to recover from this stuck state, the first step is
The supporting member and the second supporting member are moved forward, but at this time, the first supporting member moves forward to release the first pawl of the main chuck pin from the flange of the workpiece, and then the first supporting member moves forward. The first support member contacts the second support member and both move forward together to separate the second pawl at the tip of the auxiliary chuck pin from the outer periphery of the flange.

〔Example〕

Embodiments of this invention will be described below based on the accompanying drawings.

In the figure, reference numeral 1 denotes a chuck main body fixed to the main shaft of the lathe by means of bolts or the like, and a lid 2 is fixed to the rear part thereof by bolts.

Near the outer periphery of the main body 1, a plurality of diagonal holes 4 having a circular cross section are provided at equal intervals from the central axis of the main body 1 and are inclined with equal forward width relative to the central axis.

A main chuck pin 5 having a circular cross section is inserted into each of the diagonal holes 4 so as to be movable forward and backward and rotatable.

This pin 5 is formed with an axial groove 6, and a protrusion 8 on the inside of a bolt 7 screwed into the main body 1 is engaged with the groove 6 with an appropriate play. The pin 5 can be rotated within a certain range.

Further, the inside of the front end of the chuck pin 5 is recessed, and the first pawl 9 is removably fixed with a bolt, but the pawl 9 is shaped so that the inside is widened as shown in FIG. It is designed to disperse the

Further, at the rear end of the main chuck pin 5, a small diameter shaft part 10 and an engaging part 11 formed in a horizontal T-shape are integrally provided at the rear end.

12 in FIG. 1 is a first support member. This first support member has a shallow umbrella shape and is placed in a recess 13 near the rear of the main body. Further, the hollow shaft 14 at the rear of the support member 12 is connected by a bolt 15 to a piston rod of a drive cylinder, which is not shown.

Reference numeral 19 denotes a plurality of engagement grooves formed at an appropriate depth from the outer periphery of the support member 12, the width of which is slightly larger than the diameter of the small diameter shaft portion 10 of the chuck pin 5. The surface of the first support member 12 is a plane perpendicular to the center line of the chuck pin 5.

20 is a lid fixed to the front of the through hole 16 provided in the center of the main body 1; 21 is a support ring fixed to the recess 18 at the front of the main body 1; Fixed to. Also, the rear lid 2
As shown in Figure 1, there is a locking pin 22 on a part of the inner surface of the
is fixed, and this pin 22 is slidably fitted into the guide hole 23 of the first support member 12, and the support member 1 is fixed.
2 rotation stopper.

Reference numeral 24 in FIG. 1 denotes a plurality of second diagonal holes which are formed in a front-wide shape between the respective diagonal holes 4 near the outer periphery of the main body 1, and the auxiliary chuck pins 25 are inserted into these diagonal holes 24 so as to be freely advanced and retractable.

An axial groove 26 is formed in this pin 25,
By engaging this groove 26 with a protrusion 28 on the inner end of a bolt 27 screwed into the main body 1 with an appropriate play, the pin 25 can be rotated within a certain range. .

Further, a separate wide second pawl 29 is detachably fixed to the inside of the front end of the auxiliary chuck pin 25 with a bolt.

Further, at the rear end of the auxiliary chuck pin 25, a small diameter shaft part 30 and an engaging part 31 formed in a horizontal T-shape are integrally provided at the rear end.

32 in FIG. 1 is a second support member. This second support member has a shallow umbrella shape and is inserted into the recess 13 at the front. A hollow shaft 34 at the rear of the second support member 32 is fitted into the hollow shaft 14 of the first support member 12 so as to be able to move forward and backward. Also, a hollow protruding shaft 36 at the center of the front part of this second support member 32
is fitted into the through hole 16 of the main body 1 so as to be able to move forward and backward,
A push spring 37 is provided between the recess at the center of the inner surface of the front lid 20 and the stepped portion of the center hole of the second support member 32.

Reference numeral 39 denotes a plurality of engagement grooves formed at an appropriate depth from the outer periphery of the second support member 32, the width of which is slightly larger than the diameter of the small diameter shaft portion 30 of the chuck pin 25. Support members 32 before and after
The surface of the auxiliary chuck pin 25 is a plane perpendicular to the center line of the auxiliary chuck pin 25.

Next, to explain the operation of the above embodiment, FIG. 1 shows a state in which a cylindrical workpiece 41 having a flange 40 is attached.

In this state, the first support member 12 is pulled rearward by a driving means such as a hydraulic cylinder (not shown), and the first claw 9 at the tip of the main chuck pin 5 retreats along each diagonal hole 4. flange 40
is strongly pressed against the support ring 21 and fixed, and the second support member 32 at the tip of the auxiliary chuck pin 25 is moved back together with the second support member 32 that is moved back by the spring 37.
The claws 29 grip the outer peripheral surface of the flange 40. In this state, the chuck body 1 is rotated to carry out processing.

From this state, when the first support member 12 is moved forward, that is, to the right in FIG. is separated from the flange 40.
Then, the first support member 12 connects to the second support member 3.
2 and when the first support member 12 moves further forward, the second support member 32 also compresses the spring 37,
move forward together, and with this, the auxiliary chuck pin 25
also moves forward and removes the second claw 2 from the outer peripheral surface of the flange 40.
Since the parts 9 are separated, the workpiece 41 after processing can be removed.

As described above, when the second support member 32 is moved back from the position where the first support member 12 and the second support member 32 are advanced, the first and second support members 12 and 32 are initially integrated. Then I retreated and moved to the second
By gripping the outer circumferential surface of the flange 40 with the claws 29, centering is performed by aligning the center line of the workpiece 41 with the center line of the main body 1. When the first support member 12 further retreats, the support member 12 separates from the second support member 32 and retreats, and as shown in FIG. The flange 40 of 41 is pressed against the support ring 21.

〔effect〕

As described above, this invention firmly fixes the workpiece to the chuck body by pressing the workpiece against the chuck body using the first pawl provided on the main chuck pin, and the second pawl provided on the auxiliary chuck pin presses the workpiece against the chuck body. The claws grip and process the outer peripheral surface of the workpiece, such as the flange, but when attaching the workpiece to the chuck body, the second support member first works to hold the auxiliary chuck pin's outer circumferential surface. Since the second claw grips the outer peripheral surface of the workpiece, it is easy to center the workpiece when machining based on the outer peripheral surface, and since the gripping force of this second claw is obtained by a spring, the spring By adjusting the strength appropriately, centering can be performed without distorting the workpiece.

Therefore, the chuck of this invention does not require any special driving means for centering the workpiece, and after centering the workpiece reliably via the spring, the chuck firmly attaches the workpiece to the chuck body. Since it is pressed against the shaft, centering and firm fixing can be performed with a simple configuration using one driving means, and the hydraulic circuit is also simple.

In addition, since the first claw of the main chuck pin firmly presses and fixes the workpiece against the front surface of the main body from an oblique direction, the gap between the workpiece and the main body can be maintained even against strong resistance during cutting. In addition to preventing slippage, the bending load applied to the main chuck pin is smaller compared to the conventional main chuck pin that grips the outer periphery of the workpiece, and the bending load applied to the main chuck pin and the diagonal hole in contact with it are reduced. Wear is also reduced.

Furthermore, since the first and second claws that grip the workpiece are detachably fixed to the main chuck pin and the auxiliary chuck pin, respectively, they can be easily replaced depending on the shape of the workpiece. There are effects such as

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view showing one embodiment of this invention, and FIG. 2 is a front view of the same. DESCRIPTION OF SYMBOLS 1...Chuck body, 4...Diagonal hole, 5...Main chuck pin, 9...First claw, 12...First support member, 21...Support ring, 24...Second diagonal hole, 25...Auxiliary chuck pin, 29...Second pawl, 32...Second support member, 37...Press spring,
40...flange, 41...workpiece.

Claims (1)

[Scope of utility model registration request] A chuck body attached to a rotatable main shaft, and a circular cross section arranged along the periphery of the front surface of the main body, equidistant from the central axis of the main body, inclined with an equal front width with respect to the central axis. A power chuck having a plurality of diagonal holes having a main chuck pin, a main chuck pin inserted into the diagonal hole so as to be movable back and forth, and a driving means provided at the rear of the axis for driving the main chuck pin, the front end of the main chuck pin a first pawl that is removably provided on the main chuck pin and that presses the workpiece obliquely against the main body; and a first pawl that engages with the rear end of the main chuck pin;
a plurality of second diagonal holes having the same configuration as the diagonal holes provided between the first support member coupled to the driving means and moving in the axial direction on the axis of the main body and the main chuck pin; An auxiliary chuck pin inserted so as to be movable back and forth; a second pawl that is removably provided at the front end of the auxiliary chuck pin and for centering the workpiece; A second support member that straddles the main body and the support member and moves in the axial direction, and a spring that is provided between the second support member and the main body and biases the second support member in the axial direction. Then, the second pawl of the auxiliary chuck pin centers the workpiece through the second support member that is moved by the bias of the spring, and then the first support member that is moved by the operation of the drive means, A power chuck characterized in that the first claw of the main chuck pin grips a workpiece.