JPH0329545B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a spherical honing method.

[Conventional technology and problems] In spherical honing, the sphericity of workpieces up to about 50 mmφ can be improved to a high degree by three-dimensional motion: rotation of the spherical workpiece, rotation of the grindstone, and circular motion of the grindstone head. (accuracy error 1μ). However, when the spherical diameter increases, the central part of the spherical workpiece that is fixed to and rotates on the rotating shaft and the both ends close to the rotating shaft have a circular shape with respect to the grinding wheel surface that comes in contact with the center part of the workpiece that is fixed to the rotating shaft and rotates. The difference in circumference increases. This could not be determined because the accuracy was high with small diameter balls, but it turned out that this was caused by the three-dimensional movement mentioned above.

For example, with a diameter of 120mm, there was an accuracy error of approximately 15μ.
It has a relationship between grinding wheel pressure and rotation, but even if pressure is applied to the grinding wheel and processing the workpiece, the difference in rotation (rotation of the grinding wheel and workpiece, and circular motion) can be combined in various ways. There are fundamental problems that cannot be resolved.

FIG. 3 is an explanatory diagram of the machining state during honing of a spherical workpiece. In the figure, 1 is a rotating shaft that holds the spherical workpiece 3 fixedly, and 2 is a cup-shaped grindstone attached to the rotating shaft (not shown), and its grinding surface is polished to the desired finish on the spherical surface. It is made of a partially spherical surface with a matching concave shape. The rotational axis of the grindstone 2 and the rotational axis of the rotational shaft 1 fixing the workpiece are on the same plane and in orthogonal directions, but the rotational axis 1 can move in an arc around the intersection x of the two rotational axes. can.

As shown by the arrow in the figure, when the spherical workpiece 3 whose center is placed at x rotates and the grindstone 2 also rotates, the limit is the position to the left of the rotation axis of the grindstone 2, and the limit is the position to the right. , the spherical workpiece 3 is processed in the same direction by the grindstone 2,
In limited cases, facing processing is applied. In this way, during machining, the spherical workpiece 3 has a
It will undergo processing in two directions.

In facing machining, cutting is often performed due to cutting resistance, but in co-directing machining, since the balls are rotating in the same direction, there is less cutting resistance, and this characteristic becomes more noticeable as the ball becomes larger.

Ball diameters up to about 50mmφ can be processed using a set pressure and a motor for rotating the grinding wheel, but when following the conventional honing method described above, as the diameter increases, there is a limit to the ability to install a motor for rotating the grinding wheel on the grindstone head. Therefore, if the grindstone pressure is increased as it is, it will stop rotating, and the machining conditions of the machine will eventually become extremely large, and a machine with sufficient functionality will be extremely expensive.

[Object of the Invention] As mentioned above, the present invention is based on the fact that conventional outer spherical surface honing machining produces accuracy errors when machining objects with a large diameter, and that an apparatus is inevitably developed to suppress this accuracy error. The purpose of this is to improve the problem of the large size and the inability to obtain a sufficiently small precision error.

[Structure of the Invention] Therefore, the spherical honing method of the present invention eliminates the influence on accuracy caused by the conventional partial continuous machining and opposing machining using a single grindstone, as explained in FIG. Rotation of the grindstone is performed so that the same machining conditions are given to the part to be machined in the same direction as the part to be machined in the opposite direction, and the same conditions are given to the part to be machined in the opposite direction as the part to be machined in the same direction. In a spherical honing method for honing the surface of a spherical workpiece inside, an axis that intersects at the center of the spherical workpiece, which is the center of the workpiece, on the rotational axis of the spherical workpiece rotated by a rotating shaft. On a line, grindstones having the axis as a rotation axis are arranged symmetrically with the workpiece in between and rotated in the same direction, and the grindstones are rotated in the same plane including the rotation axis of the workpiece and the rotation axis of the grindstone. gives the grinding surface an arcuate motion along the surface of the workpiece,
This is a spherical honing method in which the workpiece is processed simultaneously with the grindstone.

In Figures 2A and 2B, 4 is the bed of the device. Reference numeral 5 indicates a drive unit for rotating the workpiece fixed to the bed 4, and reference numeral 6 indicates a rotating shaft to which the workpiece is attached.

Reference numeral 7 denotes a rotary disk rotatably supported by a rotary shaft 8 fixed to the bed 4. Rollers 9 are attached to the bottom surface of both ends of the rotary disk 7, and when the rotary disk 7 rotates, the rollers 9 9 slides on the surface of a receiving plate 10 fixed to the bed 4 side.

Reference numeral 11 denotes a guide plate having a groove 12, which is fixed symmetrically from the center of the rotary shaft 8 that supports the rotary disk 7, and each of the guide plates 11 is equipped with a rotary disk having the same grindstone driving section 13. The rotational axes 14 of the shafts 15 are aligned and engaged in opposing positions. In addition, in the grindstone drive unit 13, 16 indicates a motor for driving the rotating shaft.

In the figure, the spherical workpiece is attached to a rotating shaft 6, and cup-shaped grindstones 17 are attached to the tips of the rotating shaft 15, respectively.

The processing method will be described in detail later, but the rotating shaft 6 on which the spherical workpiece is attached is rotated, and at the same time, the rotating shafts 15 on which grindstones 17 are attached are rotated in the same direction, and the rotating disk 7 is rotated around the rotating shaft 8. This is carried out by swinging the grinding wheel 17 to give the grinding surface of the grinding wheel 17 an arcuate motion along the surface of the workpiece.

FIG. 1 is an explanatory diagram of the principle of the processing method of the present invention. In the figure, reference numerals 20 and 20' indicate cup-shaped grindstones attached to the rotating shafts 15 and 15 described in FIG. The rotation center axes 21 of the grindstones 20 and 20' are aligned. In addition, the grinding surface of the whetstone is
It has a partial spherical surface corresponding to the spherical surface obtained by processing a spherical workpiece. Reference numeral 22 denotes a rotating shaft for rotating the workpiece explained in FIG.
A hole formed through the center of the workpiece 24 allows the workpiece 24 to be mounted in a non-slip manner using, for example, a keyway. Attached spherical object 2
4, the center position 0 of the spherical body obtained by processing the spherical workpiece 24 is determined on the rotation axis 23 of the rotation axis 22, and the grinding wheels 20, 20' are The grindstones 20 and 20' are arranged symmetrically so that the rotation axes 21 intersect,
The rotating shaft 22 to which the workpiece 24 is attached is rotated in one direction as shown by the arrow, and the grinding wheels 20 and 20' are rotated in the same direction. An arcuate motion is applied along the surface of the workpiece 24 in the same plane including the rotational axis 23 of the workpiece 24 and the rotational axis 21 of the grindstone 17 with the center at 0, and the grinding surface of the opposing grindstone 17 simultaneously rotates the workpiece 24. This process performs spherical honing.

In the figure, the four regions divided by the rotational axis 21 and the rotational axis 23 intersecting the rotational axis 21 are defined as limit, limit, limit, limit as shown in the figure, and as shown by arrows, the grinding wheel 20 ，
Assuming that 20' rotates in the same direction and that the workpiece 24 is also placed in the rotation indicated by the arrow, the grinding resistance is small in the limit, as already explained with reference to FIG. However, the cutting resistance is large at the limit, and although the cutting resistance is large at the limit,
Cutting force is small at the limit.

[Operation] That is, when the spherical workpiece 24 rotates and is processed by the rotating grindstones 20, 20',
One half of the rotational axis 21 intersects with the rotational axis 23 of the workpiece 24 at the spherical body center position 0,
The other half is constantly machined at the end, and the other half is constantly machined at the end, but as mentioned above, the cutting resistance is small at the end, and the cutting resistance is large at the end, and the cutting resistance is large at the end, and the cutting resistance is small at the end. Therefore, one half of the spherical workpiece 24 at the limit and the other half at the limit and the limit are repeatedly subjected to the same direction machining and the opposite machining, respectively, and An arcuate motion along the surface of the workpiece 24 is performed on the grinding surface in the same plane that includes the rotational axis 23 of the spherical workpiece 24 and the rotational axis 21 of the grinding wheels 20, 20' facing the spherical workpiece 24, centered on the spherical body center position 0. By moving the grinding surface of the grinding wheel on the surface of the workpiece 24, the grinding wheel can be applied to the workpiece more often. When a trajectory is generated, the grinding wheel does not lose its correction ability and loses its grinding accuracy for the workpiece, but if you look at the surface of the workpiece partially, in the present invention, this surface is the grinding surface of the whetstone that changes sequentially. It will be processed, and the processing accuracy can be improved. Furthermore, by giving the grindstone an arcuate motion as described above, the sludge generated within the grindstone during grinding can be discharged from the periphery of the grindstone.

It has been confirmed that according to the present invention, it is possible to keep the accuracy error within 3μ for a spherical workpiece with a diameter of 120 mm.

[Effects] As explained above, the spherical honing method of the present invention uses grinding wheels that face each other and rotate in the same direction as described above, in contrast to the conventional method using a single grinding wheel. Therefore, since this is a method of applying parallel machining and opposing machining to a spherical workpiece, and applying arcuate motion to the grinding surfaces of both grinding wheels, even if the spherical workpiece to be machined becomes large, , it is possible to perform processing with extremely high precision.

In addition, when processing objects with a large diameter, conventional equipment requires a rotating shaft to rotate the workpiece, a motor to drive it, a rotating shaft to rotate the grindstone,
The motor that drives this also becomes large due to the increased pressure force during processing, and the entire device also becomes larger, but when using the processing method of the present invention,
Since machining proceeds with both grinding wheels arranged on the same rotational axis, unlike the conventional method,
Unlike machining with a grindstone from one side, the workpiece is pressed by a grindstone from both directions along the same axis, and the equipment used is much stronger than conventional ones. This is not necessary and an excellent honed surface can be obtained in a balanced state.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the principle of the processing method of the present invention. FIG. 2 shows an example of a device implementing the invention. Figure A is a front view, and Figure B is a top view. FIG. 3 is an explanatory diagram of a conventional spherical honing method. 1, 6, 22... Workpiece rotation axis, 2, 17, 2
0, 20'... Cup-shaped grindstone, 3, 24... Spherical workpiece, 4... Bed of the device, 5... Drive unit for rotating the workpiece, 7... Turntable, 8... Turntable rotating shaft, 9...roller, 10...roller receiving plate, 11...guide plate, 13...grinding wheel drive unit, 1
5...The rotation axis of the whetstone.

Claims (1)

[Claims] 1 In a spherical honing method in which the surface of a rotating spherical workpiece is honed by rotation of a grindstone, a spherical surface that is the center of the workpiece is placed on the axis of rotation of the spherical workpiece that is rotated by a rotating shaft. On axes that intersect at the body center position, grindstones having the axes as rotation axes are arranged symmetrically with the workpiece in between and rotated in the same direction, and the rotation axis of the workpiece and the rotation axis of the grindstone are aligned. A spherical honing method characterized in that the grinding surface of the grindstone is given an arcuate motion along the surface of the workpiece in the same plane, and the workpiece is simultaneously processed with the grindstone.