JPS5848037Y2 - Workpiece holding device - Google Patents

Description

[Detailed description of the invention] This invention aims to align the center of the arc-shaped machining surface with the rotation axis in order to machine an arc-shaped groove formed in the axial direction of the workpiece on the spherical outer peripheral surface of the workpiece. The present invention relates to a workpiece holding device that holds workpieces in alignment.

When machining an arcuate groove formed in the axial direction of the workpiece on the spherical outer peripheral surface of the workpiece, such as the groove formed on the outer peripheral surface of the inner ring of a constant velocity joint, the workpiece reference surface must be machined. Supported by a workpiece support surface parallel to the rotation axis of the machine,
It is necessary to hold and rotate the workpiece so that the center of the arc of the arc-shaped processing groove coincides with the axis of rotation. Figure 1 shows a conventional example of such a workpiece holding device. A second rotating shaft 3 with a workpiece holding member 2 fixed to the front end face is arranged opposite to the rotating shaft 1 so as to be movable toward the rotating shaft 1 side. A workpiece support surface 2a that supports the workpiece reference surface and positions the arc center Ow of the arc-machined groove d on the rotational axis Oc, and a reference surface 2b that abuts the upper end of the workpiece W are formed. Further, a pressing member 5 is fixed to the tip surface of the rotating shaft 1, and has a pressing surface 5a that engages with the upper end of the workpiece W as the rotating shaft 3 moves forward and clamps the workpiece W together with the reference surface 2b. ing.

When such a workpiece holding device is buttoned and the rotating shaft 3 is moved forward to clamp the workpiece W, a component force is generated in the direction of the workpiece supporting surface, and the tip of the workpiece holding device 2 moves away from the rotational axis Oc. The position of the workpiece supporting surface is displaced in the direction orthogonal to the rotation axis, which causes deviations in the holding position and holding angle of the workpiece W, making it difficult to machine the arcuate groove with high precision. It disappears.

For this reason, in the past, the lower end surface 2c of the workpiece holding member 2 was supported by a fixed block 7 fixed to the rotating shaft 1 to prevent the workpiece holding member 2 from being bent. Since a predetermined gap necessary for sliding in the axial direction is provided between the workpiece holding member 2 and the lower surface of the workpiece holding member 2, it is not only difficult to completely eliminate deflection of the workpiece holding member 2; When the gap increases due to wear of the sliding surface, the amount of deflection gradually increases, making it impossible to perform highly accurate machining.

In view of these conventional drawbacks, the present invention forms a retaining surface that forms an acute angle with the workpiece supporting surface at the tip of the workpiece holding member, and a retaining surface that makes an acute angle with the workpiece supporting surface at the tip of the other shaft, and holds the workpiece by clamping the workpiece at the tip of the other shaft. A sloped surface is provided that contacts the mating surface and applies a component force perpendicular to the workpiece support surface to the tip of the workpiece holding member to prevent the workpiece holding member from deflecting due to the workpiece clamping action. Embodiments thereof will be described below based on the drawings.

In FIG. 2, reference numeral 10 denotes a headstock placed on the table 11 of the groove processing machine, and this headstock 10 supports one rotary shaft 12 which is rotationally driven by a drive motor (not shown). A workpiece holding member 13 is attached to the front end surface of this rotating shaft 12.

At the tip of this workpiece holding member 13, as shown in FIG.
A support portion 14 forming a workpiece support surface 14a that supports the reference surface Ws of the workpiece W in parallel to the rotation axis Oc of the rotation shaft 12.
is provided protrudingly, and a workpiece support surface 1 is provided at the tip of this support portion 14.
An arcuate engagement surface 14b making an acute angle with 4a is formed.

The workpiece support surface 14a is formed at a position a predetermined distance away from the rotation axis Oc, and as shown in FIG. The workpiece W is supported at a position where the arc center Ow of d coincides with the rotational axis Oc.

Further, on the workpiece holding member 13, there is a rotation shaft 1 of the workpiece W.
A pair of reference members 17 and 18 having reference surfaces 17a and 18a in contact with the outer circumferential surface of the main shaft 17 and 18 are mounted across the main shaft axis, and a guide shaft 19 is located adjacent to the reference member 18.
is fixed.

Reference numeral 20 denotes a fixed base provided at a position facing the tip end surface of the main shaft 12. A piston body 21 is fitted into the fixed base 20 so as to be slidable in the direction of the rotational axis. A pressing force toward the rotating shaft 12 is applied by a spring 22 contracted to the rotary shaft 12 side.

The other rotating shaft 23 is coaxially supported on this piston body 21 with the rotating shaft 12 .

At the tip of the rotating shaft 23, there is a pressing surface 2 that comes into contact with the upper outer peripheral surface of the workpiece W and presses the workpiece W, as shown in FIG.
4a and an inclined surface 24b that abuts the engagement surface 14b at the tip of the workpiece holding member 13. It is worn.

Further, a protrusion 24c is provided at the tip of the clamp member 24 so as to engage with a pair of guide surfaces 14c extending in the direction of the rotational axis, which are formed on both sides of the engagement surface 14 of the workpiece holding member 13. It has become.

Furthermore, a cylinder device 27 is attached to the side of the fixed base 20, and a cylinder device 27 is fitted with the piston 26 so as to be slidable in the force direction Oo at the intersection of the axis of movement at the center of the machining surface of the tool G and the axis of rotation. At the tip of the piston rod, there is a hemispherical engagement surface 28 that engages with a circular arc groove d formed on the outer circumferential surface of the workpiece.
is formed.

Further, as shown in FIG. 5, a cylinder device 31 is mounted on the table 11, into which the piston 30 is slidably fitted in a direction perpendicular to the outer peripheral surface of the rotating shaft 12. The tip of the piston rond engages with a groove 12a carved on the outer circumferential surface of the rotating shaft 12 and supports the workpiece support surface 1.
A knock pin 32 is fixed to the rotary shaft 12 at a specific angular position where 4a is parallel to the top surface of the table.

Next, the operation of the workpiece holding device having the above configuration will be explained.

When the button is pressed at the start of operation, pressure oil is supplied to the left chamber of the piston body 21 and the rotating shaft 23 is retreated to the retreat end,
/Pressure oil is supplied to the front chamber of the cylinder device 27 and the piston 2
6 is in a retracted state, and the rotating shaft 12 is stopped at a specific angular position.

In this state, the operator should check that the circular groove d on the outer periphery of the workpiece is aligned with the guide shaft 1.
The workpiece W is placed on the workpiece support surface 14a with the phase determined so as to engage with the tip end surface of the workpiece W, and a starting switch (not shown) is pressed.

When the start switch is pressed, the cylinder device 27 is first activated.
Pressure oil is supplied to the rear chamber, the piston 26 moves forward, and the retaining surface 28 formed at the tip of the piston rond of the piston 26
engages with the arcuate groove d on the outer peripheral surface of the workpiece.

As a result, the workpiece W is correctly positioned at a predetermined angular phase, and as shown in the figure, the arcuate groove do is positioned at a position facing the machined surface of the tool G.

Then, the pressure oil is discharged from the left chamber of the piston body 21, the piston body 21 is moved to the left, and the rotating shaft 23 is moved toward the rotating shaft 12 side.

As a result, the pressing surface 24a of the clamp member 24 comes into contact with the outer peripheral surface of the workpiece, and the workpiece W is clamped.

Also, at this time, the inclined surface 24b of the clamp member 24 comes into contact with the engagement surface 14b of the workpiece holding member 13, and the tip of the workpiece holding member 13 is perpendicular to the workpiece supporting surface in a direction toward the spindle axis. A component force is generated, and the component force generated in the direction of the workpiece support surface is canceled out by the clamping of the workpiece W by the suppressing surface 24a.

Therefore, by clamping the workpiece W, the workpiece support surface 14a
The position of the workpiece W is not displaced away from the spindle axis, and the workpiece W is held at the correct position.

In this way, when the workpiece W is clamped, pressure oil is supplied to the front chamber of the cylinder device 27 and the piston 26 is retracted, and after the knock pin 32 is retracted by the cylinder device 31 on the table 11, , the rotating shaft 12 is rotated, and the tool G moves forward to process the arcuate grooves do and d3.

When the machining of the arcuate grooves do and d3 is completed, the main shaft 1
2 is stopped at a specific angle, pressure oil is supplied to the left chamber of the piston body 21, the rotating shaft 23 is retreated, and the operation is stopped.

Thereafter, the operator sequentially changes the mounting phase of the workpiece W and performs the same processing as above so that the arcuate grooves d 1 + d 2 are in a position facing the tool machining surface. Complete the processing.

As described above, in the workpiece holding device of the present invention, the tip of the workpiece holding member that supports the workpiece on the workpiece support surface parallel to the rotational axis of the processing machine is engaged with the workpiece support surface at an acute angle. A clamp member that forms a surface and is attached to the tip of the other rotating shaft and presses the workpiece toward the reference surface formed on the workpiece holding member and the workpiece support surface is engaged with the engagement surface. Since the inclined surface is perpendicular to the workpiece support surface and generates a component force in the direction toward the spindle axis, the workpiece holding member is deflected by the workpiece clamping action, and the workpiece holding position is aligned with the rotation axis. It is possible to prevent deviation in the orthogonal direction, and there is an advantage that an arcuate groove formed in the spherical outer circumferential surface of the workpiece in the direction of the workpiece axis can be machined with high precision.

In addition, in the workpiece holding device of the present invention, since the clamp member can swing in a plane that is perpendicular to the workpiece support surface and includes the rotation axis, there may be some variation in the outer diameter of the workpiece. It also has the advantage of being able to reliably hold the workpiece in the correct position even when the workpiece is

[Brief explanation of drawings]

Fig. 1 is a diagram showing the structure of a conventional workpiece holding device, Figs. 2 to 5 show an embodiment of the present invention, and Fig. 2 is a plan view showing the structure of the workpiece holding device. Figure 3 is a cross-sectional view along the ■-■ line shown in Figure 2, and Figure 4 is the IV in Figure 3.
5 is a sectional view taken along the line V-V in FIG. 2. FIG. 12... One rotating shaft, 13... Workpiece holding member,
14a... Workpiece support surface, 14b... Engagement surface, 17
゜18... Reference member, 21... Piston body, 23.
・・The other rotating shaft, 24 ・・Clamp member, 24a・
...Press surface, 24c...Slanted surface, G...Tool, W.
...workpiece.

Claims (2)

[Scope of utility model registration request] (1) In order to machine an arc-shaped groove formed on the spherical outer circumferential surface of the workpiece in the axial direction of the workpiece, the center of the arc-shaped groove is aligned with the axis of rotation of the rotating shaft. A device for holding a workpiece, the inner tip of one of a pair of rotary shafts rotatably disposed on the same axis,
A workpiece holding member having a workpiece support surface for supporting one end surface of the workpiece is fixed in a position parallel to the rotational axis of the rotational shaft and the arc center is on the rotational axis, and this workpiece holding member is fixed. Forming on the member a reference surface that engages with the outer peripheral surface of the workpiece on the other end surface side of the workpiece, and an engagement surface that is provided at the tip of the workpiece holding member and forms an acute angle with the workpiece support surface, At the inner tip of the other rotating shaft, there is a pressing surface that pushes and clamps the workpiece toward the reference surface and the workpiece support surface as the other rotating shaft moves forward, and a pressing surface that presses and clamps the workpiece toward the reference surface and the workpiece support surface as the other rotating shaft moves forward. a clamping member having an inclined surface that comes into contact with the workpiece and cancels a component force in the direction of the workpiece support surface caused by clamping the workpiece, and a drive device that moves the other rotating shaft in an axial force running direction. A workpiece holding device characterized by: (2) The clamp member is configured to be able to swing in a plane that is perpendicular to the workpiece support surface, includes the rotation axis, and is parallel to the rotation axis.
The workpiece holding device described in Section 1.