JP3682819B2 - Chuck - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mechanism for centering a workpiece in a chuck used for turning.
[0002]
[Prior art]
For example, in a finger chuck for processing an aluminum wheel, conventionally, as shown in FIG. 5, a center pad 53 is attached to the attachment portion 52 on the front surface of the chuck body 51 and the outer periphery of the center pad 53 is contacted with the inner peripheral surface of the workpiece W. A mechanism is known in which a plurality of centering portions 54 in contact with each other are formed in a tapered shape, and the centering portions 54 center the workpiece W from the inside.
[0003]
[Problems to be solved by the invention]
However, according to the conventional centering mechanism, since the centering portion 54 is formed in a tapered shape, there are the following problems.
(1) The workpiece W may bite into the centering portion 54, and the removal of the workpiece W may be hindered.
(2) Since the centering portion 54 always abuts against the workpiece W at the same location, the centering portion 54 is likely to be worn. When the degree of wear increases, the center pad 53 must be replaced.
(3) Since the centering portion 54 is integrally formed with the center pad 53, when the centering portion 54 does not contact the workpiece W correctly, a troublesome adjustment work such as regrinding the centering portion 54 is required.
[0004]
Accordingly, an object of the present invention is to provide a chuck that can prevent biting between the centering portion and the workpiece, can suppress wear of the centering portion, and can adjust the position of the centering portion in the chuck radial direction.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the chuck of the present invention is provided with a plurality of gripping claws for gripping a workpiece and a plurality of centering tools for centering the workpiece on the chuck body, and each centering tool is centered on the rotation axis. A centering portion that is rotatable about an axis in a substantially tangential direction of the circle to be rotated, and a curved surface that contacts the workpiece is provided at the centering portion . Further, means for adjusting the position of the centering tool in the chuck radial direction is provided so as to cope with a change in the workpiece diameter .
[0006]
The chuck of the present invention is provided with three gripping claws for gripping the workpiece from the outside on the outer periphery of the chuck body in order to center a large-diameter workpiece such as an aluminum wheel with high accuracy. The centering tool is provided with a centering roller that comes into contact with the work so as to be rotatable about a substantially tangential axis of a circle centering on the rotation axis. . Further, means for adjusting the position of the centering tool in the chuck radial direction is provided so as to cope with a change in the workpiece diameter .
[0007]
Here, preferably, in order to make the centering roller come into contact with the inner peripheral surface of the workpiece reliably by using the draft of the workpiece, a substantially triangular center pad can be slightly moved in the rotation axis direction on the front surface of the chuck body. Means for supporting and urging the center pad toward the workpiece may be provided, and the centering tool may be provided at the three corners of the center pad so as to be positioned approximately in the middle of the adjacent gripping claws.
[0008]
Also, with the wear or damage of the centering portion may be provided with means for attaching the core Daegu interchangeably (claim 4).
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments in which the present invention is applied to a finger chuck for processing an aluminum wheel will be described with reference to the drawings. As shown in FIGS. 1 and 2, the chuck body 1 of the finger chuck includes a body 2 attached to a main shaft (not shown) of a lathe and a face plate 3 assembled on the front surface of the body 2. A draw sleeve 4 and a spider 5 are provided inside the body 2 so as to be movable in the chuck axis direction, and are driven back and forth by a rotating cylinder (not shown) on the main shaft side.
[0010]
A clamp lever 6 is pivotally mounted by means of a pin-shaped groove 7 in the central portion through a pin 8 at a position at which the outer periphery of the face plate 3 is equally divided, and a workpiece W (aluminum wheel) is attached to the main shaft. A work locator 10 having a seating portion 9 for seating at a predetermined position from the end face is fixed. A gripping claw 11 for gripping the chuck side end of the workpiece W from the outside is provided at the front end of the clamp lever 6, and the rear end of the clamp lever 6 is connected to the spider 5 via a shaft 12. The finger chuck of this embodiment is configured to drive the clamp lever 6 via the draw sleeve 4 and the spider 5 by a rotating cylinder, and to clamp and unclamp the workpiece W by three gripping claws 11.
[0011]
A slider 14 is supported in the center hole 3a of the face plate 3 so as to be slightly slidable in the direction of the chuck rotation axis while being prevented from rotating by a pin 16 and biased toward the workpiece by a spring 15. A substantially triangular center pad 17 is removably assembled with a bolt 18 on the front surface of the slider 14. The center pad 17 is provided with a saddle hole 19 that fits into the bolt 18, and by tightening one end of the saddle hole 19 against the bolt 18, the three corners 17 a of the center pad 17 are positioned between the adjacent gripping claws 11. Has been. And the centering tool 21 which centers the chuck | zipper side edge part of the workpiece | work W from the inner side is attached to these three corner | angular parts 17a.
[0012]
As shown in FIGS. 2 and 3, the base 22 of each centering tool 21 is fitted in the groove 23 of the center pad 17, and the position of the centering tool 21 can be adjusted in the chuck radial direction through a long hole 25 by a plurality of mounting bolts 24. The center pad 17 is detachably assembled. A centering roller 26 having a cylindrical surface in contact with the inner peripheral surface of the workpiece W is disposed at the tip of the base 22 at a substantially right angle with respect to a substantially tangential direction of a circle centered on the rotation axis, that is, a radial line centered on the rotation axis. It is rotatably supported by a roller pin 27 in the formed direction. Further, an adjustment bolt 29 provided with a nut 28 is screwed onto the chuck 22 side end surface of the base 22, and a through hole 30 is formed in the center pad 17 so that the head of the adjustment bolt 29 contacts. Then, the adjusting bolt 29 is turned with a tool inserted into the through hole 30, the position of the centering roller 26 together with the base 22 is adjusted in the chuck radial direction within the length range of the long hole 25, the nut 28 is tightened, and the base 22 is fixed. It can be fixed to the center pad 17. The rotation axis of the centering roller 26 may be slightly inclined with respect to the tangent as long as it rotates in contact with the workpiece W during the centering operation.
[0013]
In the finger chuck having the above-described configuration, when the workpiece W is attached, three portions on the inner peripheral surface thereof are applied to the centering roller 26, the center pad 17 is slightly moved back together with the slider 14, and 60 ° from the centering roller 26 is obtained. The end face of the workpiece W is brought into contact with the seating portion 9 of the workpiece locator 10 at different phases, and in this state, the three clamp levers 6 are closed and the outer circumference of the workpiece W is gripped by the gripping claws 11. When removing the workpiece W, after opening the clamp lever 6, the workpiece W is pulled forward from the chuck body 1.
[0014]
According to the finger chuck of this embodiment, since the center pad 17 is biased toward the workpiece by the spring 15, the centering roller 26 is moved to the workpiece inner peripheral surface by utilizing the draft of the workpiece W when the workpiece is mounted. It can be reliably contacted. Further, since the centering roller 26 is in contact with the workpiece W on the cylindrical surface, when the workpiece is removed, the centering roller 26 is rotated to prevent the workpiece W from biting, and this can be smoothly performed from the chuck body 1. Can be pulled apart.
[0015]
On the other hand, since the centering roller 26 is a rotating body, the cylindrical surface at a different location contacts the workpiece W each time. For this reason, compared with the conventional taper system, the abrasion of the centering part which contacts the workpiece | work W can be suppressed, and the lifetime of the centering roller 26 improves. If the centering roller 26 does not correctly contact the workpiece W due to a dimensional error or the like, the mounting bolt 24 and the nut 28 are loosened, and the adjustment bolt 29 is turned to adjust the position of the base 22 in the chuck radial direction. In this way, the workpiece W can be accurately centered by a simple adjustment operation in the centering tool 21 without replacing the center pad 17.
[0016]
When the centering roller 26 is worn or damaged, only this roller 26 or only the centering tool 21 need be replaced. In this case, the center pad 17 need not be replaced. If the inner diameter changes greatly due to a change in the type of workpiece W, the center pad 17 may be removed from the slider 14 and replaced with another centering unit.
[0017]
FIG. 4 shows a modified example of the centering tool 21. Here, a centering ball 32 is rotatably held at the tip of the base 22 via a holder 33. Also with this configuration, when the workpiece is removed, the centering ball 32 rotates around the axis in the substantially tangential direction of the circle with the chuck rotation axis as the center to prevent the workpiece W from biting, so that it is the same as in the case of the roller 26. The workpiece W can be smoothly separated from the chuck body 1. Further, the fan-shaped centering portion may be rotatably supported by the centering tool, and the arc surface thereof may be brought into contact with the workpiece W. Further, when a sphere is used as the centering ball 32 and the sphere is held so as to freely rotate, the centering ball 32 is rotated around an axis in a substantially tangential direction of a circle centering on the rotation axis. Is possible. In addition, the present invention is not limited to the above-described embodiment, and the shape and configuration of each part are appropriately determined without departing from the gist of the present invention, such as application to a chuck of a type in which a workpiece is centered from the outside by a centering tool. It is also possible to change and implement.
[0018]
【The invention's effect】
As described above in detail, according to the first aspect of the present invention, the curved surface of the pivotable centering portion is brought into contact with the workpiece for centering, so that the centering portion and the workpiece can be prevented from being bitten, There is an effect that wear of the protruding portion can be suppressed. Further, since the means for adjusting the position of the centering tool in the chuck radial direction is provided, there is an effect that the position of the centering portion in the chuck radial direction can be adjusted in accordance with the change in the workpiece diameter.
[0019]
According to the second aspect of the present invention, the cylindrical surface of the centering roller is brought into contact with the inner peripheral surface of the workpiece for centering, so that there is an effect that a large-diameter workpiece such as an aluminum wheel can be centered with high accuracy. Further, since the means for adjusting the position of the centering tool in the chuck radial direction is provided, there is an effect that the position of the centering portion in the chuck radial direction can be adjusted in accordance with the change in the workpiece diameter.
[0020]
According to the third aspect of the present invention, the centering tool having the centering roller is attached to the center pad that is slightly movable in the chuck rotation axis direction. There is an effect that can reliably contact the surface.
[0022]
According to the invention of claim 4 , there is an effect that the centering tool can be replaced when the centering portion is worn or damaged.
[Brief description of the drawings]
FIG. 1 is a cutaway side view of a main part of a finger chuck showing an embodiment of the present invention.
FIG. 2 is a front view of the chuck of FIG.
FIG. 3 is an enlarged view of a centering tool in the chuck of FIG. 1;
FIG. 4 is an enlarged view of a main part showing a modified example of the concentric tool.
FIG. 5 is a cutaway side view of a main part showing a conventional chuck.
[Explanation of symbols]
1 ・ ・ Chuck body, 6 ・ ・ Clamp lever, 10 ・ ・ Work locator, 11 ・ ・ Grip claw, 14 ・ ・ Slider, 17 ・ ・ Center pad, 21 ・ ・ Centering tool, 22 ・ ・ Base, 24 ・ ・ Installation Bolt, 25 ... Long hole, 26 ... Centering roller, 29 ... Adjusting bolt, 32 ... Centering ball, W ... Workpiece.

Claims (4)

The chuck body is provided with a plurality of gripping claws for gripping the work and a plurality of centering tools for centering the work, and includes means for adjusting the position of the centering tool in the chuck radial direction, and each centering tool is centered on the rotation axis. A chuck comprising a centering portion that is rotatable about an axis line in a substantially tangential direction of a circle to be provided, and a curved surface that is in contact with a workpiece is provided on the centering portion. Three gripping claws for gripping the workpiece from the outside are provided on the outer periphery of the chuck body, and three centering tools for centering the workpiece from the inside are provided on the front surface of the chuck body, and means for adjusting the position of the centering tool in the chuck radial direction Each of the centering tools is provided with a centering roller that comes into contact with the work so as to be rotatable about an axis in a substantially tangential direction of a circle around the rotation axis.   A substantially triangular center pad is supported on the front surface of the chuck body so as to be slightly movable in the direction of the rotation axis, and a means for biasing the center pad toward the workpiece is provided. The chuck according to claim 2 attached so that it may be located in the middle of a claw. The chuck according to claim 1, 2 or 3, further comprising means for attaching the centering tool in a replaceable manner.

Images