JPH08300246A - Machining unit - Google Patents

Abstract

PURPOSE: To provide a machining unit capable of preventing the promotion of being centrally recessed in an internal surface machining form. CONSTITUTION: During the reciprocating motion of a tool spindle 2, a rocking motion in this tool spindle 2 is carried out. This reciprocating motion is made by an alteration in radial floating desired value of a reciprocating movement or rocking motion of a reciprocating table 4. It is so set that the rocking motion is made so as to turn to a horizontal direction and a period of this rocking motion so as to be synchronized with the reciprocating motion as well as a resultant locus between the reciprocating motion and the rocking motion is set so as to become a projected curve. Therefore the radial floating desired value is altered to be suited to these conditions. In brief, prevention of the promotion of being centrally recessed is not to tilt the tool spindle 2 and the whole support system, but it will do that the tool spindle 2 itself is merely rocked within the movable range of the tool spindle 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing device for grinding an inner surface of a cylindrical work by means of a processing tool such as a grindstone, and more particularly to a processing device capable of easily preventing the inner surface processing shape from being concave.

[0002]

2. Description of the Related Art Conventionally, as a method for grinding the inner surface of a cylindrical work, for example, a method shown in FIG. 4 has been known. This method involves rotating a work W and a tool spindle 2 and then rotating the work W onto the tool spindle 2. The grindstone 6 is brought into contact, and the tool spindle 2 and the grindstone 6 are reciprocally moved in the directions indicated by the arrows in the figure.

[0003]

However, when the reciprocating movement of the grindstone 6 is performed during the inner surface grinding as described above, the grindstone 6 contacts the center of the work W for the longest time. Tend to be concave at the center, and a desired processed shape cannot be obtained. For this reason, it is not possible to grind parts that need to be center-convex, such as bearing inner rings, from the viewpoint of press-fitting and adhesion accuracy.

Further, in order to prevent the inner surface machining shape of the work W from being a concave shape in the center, the tool spindle 2 is tilted at a constant angle together with its support system, and thereby the contacting manner of the grindstone 6 to the work W is adjusted. Good, but in this case, because it is necessary to separately provide a fine adjustment device for finely adjusting the position of the tool spindle 2 and its support system, the device structure becomes complicated accordingly and the center of the inner surface machining shape can be easily Indentation cannot be prevented.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a processing apparatus capable of easily preventing a central concave shape of an inner surface processing shape.

[0006]

In order to achieve the above object, the invention according to claim 1 has a tool spindle having a working tool at its tip, a magnetic bearing rotatably supporting the tool spindle, and the tool. In a machining apparatus comprising a reciprocating means for reciprocating a spindle in an axial direction, a swinging means for performing a radial swinging motion of the tool spindle during the reciprocating movement of the tool spindle by the reciprocating means is provided. Characterize.

According to a second aspect of the present invention, a magnetic bearing comprises a radial electromagnet arranged around a tool spindle, a radial displacement sensor section for detecting a radial displacement of the tool spindle, and the radial displacement sensor section. And the preset target value of the tool spindle in the radial direction, and based on the result of this comparison, it comprises a control unit that adjusts the exciting current of the radial electromagnet. It is characterized by comprising target value changing means for sequentially changing the radial levitation target value in the movement direction.

According to a third aspect of the invention, the direction of the swing motion is
It is characterized by being horizontal, vertical or in any direction.

The invention according to claim 4 is characterized in that it comprises a start time setting means for setting the start time of the swing motion to an arbitrary time during the machining process.

The invention according to claim 5 is characterized in that the start timing of the oscillating movement is during finishing.

According to a sixth aspect of the invention, the period of the swing motion is
The cycle is synchronized with the reciprocating motion of the tool spindle.

According to the invention described in claim 7, the period of the swinging motion is
It is characterized in that the cycle is different from that of the reciprocating motion of the tool spindle and is different.

The invention according to claim 8 is characterized in that the combined trajectory of the swinging motion and the reciprocating motion is a convex curve.

The invention according to claim 9 is characterized in that the combined trajectory of the swinging motion and the reciprocating motion is a concave curve.

[0015]

According to the present invention, during the reciprocating motion of the tool spindle, the tool spindle itself is swung to adjust how the grindstone hits the workpiece, thereby making the inner surface machining shape of the workpiece a concave shape. To prevent.

In particular, according to the second aspect of the invention, the radial levitation target value of the tool spindle is sequentially changed, whereby the tool spindle is swung.

According to the eighth aspect of the present invention, since the combined locus of the swinging motion and the reciprocating motion is a convex curve, the inner surface machining shape of the work can be made into a central convex shape, and the press fitting / adhesion accuracy and the like can be improved. From the point of view, it is suitable for processing parts that require a central convex shape, such as bearing inner rings.

Further, the invention according to claim 9 is suitable for intentionally making the inner surface processing shape of the work into a central concave shape because the synthetic locus is a concave curve.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a processing apparatus according to the present invention will be described in detail below with reference to FIGS.

As shown in FIG. 1, this processing apparatus is equipped with a spindle unit 1. The spindle unit 1 contains a tool spindle 2 and a magnetic bearing 3 for rotatably levitationally supporting the spindle 2, and on a reciprocating table 4. It is installed in.

A grindstone 6 which is a processing tool is attached to the tip of the tool spindle 2 via a quill 5, and the reciprocating table 4 is capable of reciprocating along the axial direction of the tool spindle 2 (the direction of the arrow in the drawing). It is provided.

The reciprocating movement of the tool spindle 2 and the grindstone 6 in the axial direction is carried out by the reciprocating movement of the reciprocating table 4.

The magnetic bearing 3 is composed of radial magnetic bearing parts 7, 7 arranged on both ends of the tool spindle 2 and control parts 8, 8 thereof.

The radial magnetic bearing portion 7 is a radial electromagnet 7.
00, 700 ... And a radial displacement sensor unit 701. The radial electromagnets 700, 700 ... Are located around the tool spindle 2 and are installed so as to face the outer peripheral surface of the tool spindle 2. The unit 701 detects the radial displacement of the tool spindle 2 and outputs it to the control unit 8.

The control unit 8 is a radial electromagnet 700, 700.
Is for adjusting the exciting current, and the adjusting of the exciting current here is performed by using the detection value from the radial displacement sensor unit 701.
This is executed based on the comparison result by comparing with a preset radial levitation target value of the tool spindle 2.

The control unit 8 is connected to the CPU 10 via an interface (not shown) and the like.
0 indicates the swinging motion of the tool spindle 2 and the grindstone 6 in the radial direction.
Swinging means (target value changing means) executed during the reciprocating motion of
Is configured.

That is, the CPU 10 is configured to output the swing motion command S for executing the swing motion of the tool spindle 2 to the control units 8 and 8, and output such swing motion command S. Occurs during the reciprocating movement of the tool spindle 2.

The swing motion command S is a command for sequentially changing the above-mentioned radial levitation target value, and this command causes the above-mentioned radial levitation target value to be sequentially changed. Here, the direction of the rocking motion is horizontal, the cycle of the rocking motion is synchronized with the cycle of the reciprocating motion, and the combined trajectory of the reciprocating motion and the rocking motion is shown by the dotted arrow in FIG. It is set to such a convex curve. Therefore, the radial levitation target value is changed to meet these conditions.

Further, the CPU 10 has a start setting function,
The start time setting function sets the start time of the swing motion as described above at an arbitrary time during the machining process. With this function, for example, the start time of the swing motion can be set during finishing machining. .

The axial direction of the tool spindle 2 is supported by an axial magnetic bearing portion 9, and the axial magnetic bearing portion 9 has a disk 900 and an axial electromagnet 901.
901 and an axial displacement sensor section 902, the disk 900 is integrally attached to the tool spindle 2, and the axial electromagnets 901 and 901 are the tool spindle 2
Is located in the vicinity of the tool spindle 2 and is opposed to the tool spindle 2 via the disc 900.
Is detected in the axial direction and output to a control unit (not shown).

The control unit (not shown) is an axial electromagnet 9
No. 01, 901 is adjusted, and the adjustment of the exciting current is performed by comparing the detected value from the axial displacement sensor section 902 with a preset axial levitation target value of the tool spindle 2. It executes based on this comparison result.

Next, the operation of the processing apparatus configured as described above will be described with reference to FIGS.

According to this processing apparatus, when the inner surface of the cylindrical work W is ground, the work W and the tool spindle 2 rotate and come into contact with each other. The reciprocating movement of the reciprocating table 4 causes the tool spindle 2 and the grindstone 6 to reciprocate.

During the reciprocating motion as described above, the CPU
A swing motion command S is output from 10 to the control unit 8, whereby the radial levitation target value of the tool spindle 2 is sequentially changed, and the tool spindle 2 and the grindstone 6 swing horizontally.

At this time, the cycles of the oscillating motion and the reciprocating motion are synchronized, and the combined trajectory of the reciprocating motion and the oscillating motion becomes a convex curve as shown by the dotted line in the figure.

That is, when the stroke of the oscillation motion is the maximum L _max as shown in FIG.
While the maximum inclination angle is “θ _max ”, the stroke of the oscillation motion is minimum L _{min as} shown in FIG.
In the case of, the inclination angle of the grindstone 6 becomes the minimum “θ _min ”, and in the middle thereof, the inclination angle of the grindstone 6 becomes “0”.

When the grindstone 6 swings while changing the inclination angle in the horizontal direction in this manner, the way the grindstone 6 hits the work W is adjusted, and the inner surface shape of the work W is shown in FIG.
As shown in (a), it is ground to a convex shape.

Therefore, in the machining apparatus of the above-described embodiment, the tool spindle 2 itself is swung during the reciprocating motion of the tool spindle 2, thereby adjusting how the grindstone 6 hits the work W. It is configured to prevent the inner surface processing shape of the work W from becoming a central concave shape. Therefore, the prevention of the central concave shape does not require the tool spindle 2 and the entire supporting system thereof to be tilted, but only needs to swing the tool spindle 2 itself within the movable range of the tool spindle 2. It is possible to prevent the processed shape from becoming concave.

In particular, in this machining apparatus, since the combined locus of the oscillating motion and the reciprocating motion is a convex curve, the inner surface machining shape of the work can be made into a central convex shape, and the press fitting / adhesion accuracy and the like can be considered. Therefore, it is suitable for processing parts that need to be center-convex, such as bearing inner rings.

The direction of the swing motion of the tool spindle 2 and the grindstone 6 is not limited to the horizontal direction, but may be vertical or arbitrary.

The period of the oscillating motion may not be synchronized with the period of the reciprocating motion, but may be a different period asynchronous with the reciprocating motion.

The combined locus of the swinging motion and the reciprocating motion can be set to a concave curve as shown by the dotted arrow in FIG. 3 (b). In this case, the inner surface shape of the work W should be a central concave shape. This is suitable for intentionally making the inner surface processing shape of the work W a concave shape.

[0043]

As described above, the machining apparatus according to the present invention oscillates the tool spindle itself during the reciprocating motion of the tool spindle, thereby adjusting how the grindstone hits the workpiece.
It is configured so as to prevent the inner surface processed shape from being concave. For this reason, the prevention of the central concave shape does not need to tilt the tool spindle and the entire supporting system thereof, but only needs to swing the tool spindle itself within the movable range of the tool spindle. The central concave shape can be prevented.

In the inventions according to claims 2 to 7, the same effects as described above can be obtained.

According to the eighth aspect of the present invention, since the synthetic locus of the swinging motion and the reciprocating motion is a convex curve, the inner surface machining shape of the work can be a central convex shape, and the press-fitting
It is suitable for machining parts that need to be convex in the center from the viewpoint of adhesion accuracy and the like, such as bearing inner rings.

According to the ninth aspect of the invention, since the combined locus of the swinging motion and the reciprocating motion is a concave curve, it is suitable to intentionally make the inner surface machined shape of the workpiece a concave shape. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a processing apparatus according to the present invention.

FIG. 2 is an operation explanatory view of the processing apparatus shown in FIG.

FIG. 3 is an operation explanatory view of the processing apparatus shown in FIG.

FIG. 4 is an explanatory view of conventional inner surface grinding.

[Explanation of symbols]

2 tool spindle 3 magnetic bearing 4 reciprocating table (reciprocating means) 6 grindstone (working tool) 8 control unit 10 CPU (oscillating means, target value changing means, start setting means) 700 radial electromagnet 701 radial displacement sensor section

Claims (9)

[Claims] 1. A machining apparatus comprising: a tool spindle having a working tool at its tip; a magnetic bearing that rotatably floats and supports the tool spindle; and a reciprocating means that reciprocates the tool spindle in the axial direction. A machining apparatus comprising swinging means for performing radial swinging movement of the tool spindle during reciprocating movement of the tool spindle by the reciprocating means. 2. A magnetic bearing, a radial electromagnet disposed around a tool spindle, a radial displacement sensor section for detecting a radial displacement of the tool spindle, a detection value of the radial displacement sensor section and a value in advance. It consists of a control unit that compares the set radial levitation target value of the tool spindle and adjusts the exciting current of the radial electromagnet based on the result of this comparison. The processing apparatus according to claim 1, further comprising target value changing means for sequentially changing the directional levitation target value. 3. The processing apparatus according to claim 1, wherein the direction of the oscillating movement is horizontal, vertical, or arbitrary. 4. The processing apparatus according to claim 1, further comprising a start time setting means for setting the start time of the swing motion to an arbitrary time during the processing process. 5. The processing apparatus according to claim 1, wherein the start timing of the swing motion is during finishing processing. 6. The machining apparatus according to claim 1, wherein the cycle of the swing motion is a cycle synchronized with the reciprocating motion of the tool spindle. 7. The machining apparatus according to claim 1, wherein the cycle of the oscillating motion is a different cycle that is different from the reciprocating motion of the tool spindle. 8. The processing apparatus according to claim 1, wherein the combined trajectory of the swinging motion and the reciprocating motion is a convex curve. 9. The processing apparatus according to claim 1, wherein a combined trajectory of the swinging motion and the reciprocating motion is a concave curve.