JPH0433579B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grinding method for grinding a workpiece with high precision.

As shown in FIG. 1, the grinding method in a normal rotary type grinding machine is to place a large number of workpieces 2 on a rotary table 1 rotating in the direction of arrow A', and to Grinding is performed using a rotary grindstone 3 that is separated by the same distance. A workpiece 2 is drawn on the same circumference on the rotary table 1 at a certain distance from the rotation axis 1a.
A rotary grindstone 3 is provided whose axis is at a point 3a' that is a distance a from the rotation axis 1a. When the rotary table 1 is rotated in the direction of arrow A', an inner circle 4 drawn by the workpiece 2 is created. Then, when the rotary whetstone 3 is rotated in the direction of arrow B' opposite to the traveling direction of the workpiece 2, an outer diameter circle 5 of the rotary whetstone 3 is created. As shown in FIG. 2, the rotary grindstone 3 has a substantially annular grinding surface, and the workpiece 2 can be ground with this substantial grinding surface. In this method, during grinding, the diameter circle 4 drawn by the work 2 as the rotary table 1 rotates intersects the outer diameter circle 5 of the rotary grindstone 3, and the rotation direction of the work 2
A' and the rotation direction B' of the grindstone 3 are substantially perpendicular to each other.

At the point where the inner diameter circle 4 of the workpiece 2 and the outer diameter circle 5 of the rotary grindstone 3 touch, the two contact each other so as to intersect at a substantially right angle. When the rotational speed of the rotary table 1 is increased in order to increase the grinding efficiency, a strong impact force is generated on the workpiece 2, which has the disadvantage that the workpiece 2 is easily damaged.

This damage will be explained in FIG. FIG. 2 is a view showing the grinding portion of FIG. 1, and when the rotary grindstone 3 and the workpiece 2 come into contact with each other, there are two grinding contact surfaces as shown by the shaded areas. When the workpiece 2 comes into contact with the substantial grinding surface of the rotary grindstone 3 so as to intersect at right angles, the contact time becomes short and the grinding length becomes short, so that the amount of grinding per unit time becomes large. In other words, the amount of grinding per rotation of the rotary grindstone increases. Since the amount of grinding per rotation is large, a strong impact force is generated when the workpiece 2 is ground. One factor that causes damage to the workpiece 2 is this impact force.

Further, the grinding contact surface shown by the shaded area in FIG. 2 is designed only in a part of the workpiece 2, and is constantly subjected to concentrated grinding force and impact. In this shaded area, the workpiece 2 is ground so as to cross the workpiece 2, and since the grinding contact surface is small, the workpiece 2 is easily subjected to a concentrated load, leading to breakage of the workpiece 2.

In other words, if a large number of workpieces are placed on the same circumference and ground with a rotating grindstone that has a substantially annular grinding surface at right angles to the circumference of the workpieces, the workpiece 2 will have cracks and chips. occurs, and a decrease in surface roughness is unavoidable.

The present invention solves the above-mentioned conventional drawbacks by grinding a workpiece in a positional relationship between the workpiece and the grindstone such that the radius circle drawn by the workpiece as the rotary table rotates almost contacts the outer diameter circle of the rotary grindstone. This is what I am trying to do.

The present invention will be explained below based on the embodiments shown in FIGS. 3 and 4.

To grind a large number of workpieces 2 at once, the workpieces 2 are arranged in an annular shape concentrically with the continuously rotating rotary table 1 so that the workpieces 2 and the grinding wheel 3 are always in contact with each other at one fixed position. Then, a grinding contact surface is created by an annular workpiece 2 and a rotary grindstone 3, and grinding is performed using this grinding contact surface while both the rotary table 1 and the rotary grindstone 3 are continuously rotated.

In this way, the contact surface between the workpiece 2 and the rotary grindstone 3, which is the grinding surface, is large and the surface pressure is small, and the grinding is carried out slightly in parallel at a fixed position as the rotary table rotates. No cracks or chips occur, greatly improving production efficiency and yield. Normally, grinding is performed in two steps using a single rotary table and its rotation period, with right angle contact, but in the present invention, grinding is performed in parallel contact and in one step.

At a fixed position where the inner diameter circle 4 drawn by the workpiece 2 and the outer diameter circle 5 of the rotary grindstone 3 touch, the workpiece is ground to the first grinding amount every revolution of the rotary table during continuous rotation of both.

In other words, there is only one grinding surface in parallel contact,
The work pieces 2 placed in a circular ring without interruption are ground in one process.

The conventional right-angled contact, grinding surface in two places, and grinding in two steps is disclosed in Japanese Patent Application Laid-Open No. 56-21756, and is satisfactory depending on the use such as the size and shape of the workpiece. JP-A-56-139865 has an example of the use of a grindstone, and has a general grindstone arrangement similar to that of the above-mentioned publication.

Furthermore, Japanese Patent Application Laid-Open No. 53-24198 states that cycloidal relative motion grinding is preferable.

In any case, although it depends on the application, the method of the present invention is most suitable for simultaneously grinding a large number of workpieces made of difficult-to-cut materials such as non-ferrous metals.

Figure 3 shows the positional relationship between the workpieces on the rotary table and the rotating grindstone.A large number of workpieces 2 are placed on the same circumference on the rotary table 1, and as the rotary table 1 rotates, the workpieces are The rotational axis 3a of the grindstone 3 is separated from the rotational axis 1a of the rotary table 1 by a distance b so that the inner diameter circle 4 drawn by 2 and the outer diameter circle 5 of the grindstone 3 are almost in contact with each other.
That is, on the rotary table 1 rotating in the direction of arrow A, workpieces 2 are placed on the circumference drawn at a certain distance from the rotation axis 1a, and the circumference is covered by a large number of workpieces 2. The inner diameter circle 4 of the workpiece 2 is created above.

The rotation axis 1a of the rotary table 1 is almost the same as the axis of the inner diameter circle 4 of the workpieces 2, and a large number of workpieces 2 are arranged like a ring having an inner diameter circle 4 and an outer diameter circle. . As shown in FIG. 3, if the workpiece 2 is square, the workpieces are placed on the same circumference in the radial direction from the rotational axis 1a so that they are in contact on the inner diameter circle 4 side and are spaced apart on the outer diameter circle side. Place work 2.

On the other hand, the rotary grindstone 3 rotates in the direction of arrow B, with its rotation axis 3a being from the rotation axis 1a of the rotary table 1, and the rotary table 1 and the rotary grindstone 3 rotate in opposite directions as shown in FIG. , and are spaced apart by a distance b. This distance b is
The dimensions and positional relationship are such that the outer diameter circle 5 of the substantial grinding surface of the rotary grindstone 5 is in contact with the inner diameter circle 4 of the workpiece 2 . In this positional relationship, the corners of the rotary grindstone 3 are rounded due to initial shaping, grinding and wear. A substantial outer diameter formed as a rotating grindstone,
Although it is different from the outer diameter surface 5 of the substantial ground surface, there is no large difference and it may be considered that they are almost the same. However, since one of the purposes of grinding is to grind the workpiece 2 evenly over the entire surface, the actual outer diameter circle 5 of the grinding surface is important. In the conventional example, the rotary grindstone 3
Since this is orthogonal to the annular shape in which the workpieces 2 are arranged, the outer diameter circle 5 is not very important.

The workpiece 2 on the rotary table 1 is merely placed, but not exactly placed, so that it substantially has a circular ring shape with some unevenness.

Then, the center of rotation is made so that the outer diameter circle 5 of the rotary grindstone 3 and the inner diameter circle 4 of the workpieces 2 placed in an annular shape are almost in contact with each other as the rotary table 1 rotates. If they are separated by a distance b, that is, the inner circle 4 and the outer circle 5 are almost in contact with each other, they will be in contact with each other almost parallel to each other.

Figure 4 shows the parallel contact state, where work 2
The grinding surface of the rotary grindstone 3 hits parallel to the direction in which the grinding wheel travels, creating a grinding contact surface. As a result, the traveling direction of the workpiece 2 and the rotating direction of the grindstone 3 during grinding become almost parallel, and the length of contact between the workpiece 2 and the grindstone 3 increases, and the speed of the rotary table 1 is increased to increase grinding efficiency. In this case, the impact force on the workpiece 2 is reduced.

In addition, as shown in Fig. 4, the grindstone 3 and the workpiece 2
Since the contact surface is larger than that in the normal grinding method as shown by the shaded area, the grinding force is dispersed and the workpiece 2 is not cracked, chipped, or deteriorated in surface roughness.

It is important that the contact surface be wide and in one place, and that it be ground so that it touches the workpiece 2 almost parallel to its traveling direction. Even if adjacent workpieces are lined up with some unevenness, if the outer diameter circle of the actual grinding surface is in contact with the minimum inner diameter circle, there will be no grinding steps or grinding residues. All the workpieces can be ground uniformly and equally over the entire surface.

The grinding step can reduce the surface roughness by reducing the amount of grinding per rotation of the rotary grindstone and increasing the time that the workpiece and the rotary grindstone are in contact with each other. That is, according to the method of the present invention, the contact surface to be ground is large and the surface pressure can be maintained in a low state, and satisfactory grinding can be achieved without decreasing the production amount.

By grinding using the grinding method of the present invention described above, the surface roughness of the workpiece is reduced to 0.1 μmRmax in the conventional method shown in FIG. 1, but 0.01 μmRmax in the present invention.
It is possible to prevent the occurrence of cracks, chips, etc. on the workpiece.

As explained above, according to the present invention, it is possible to greatly improve the finishing accuracy especially in grinding difficult-to-cut materials such as non-ferrous metals.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a conventional grinding method in a rotary type grinder, Fig. 2 is an enlarged view of the grinding wheel portion of Fig. 1, and Fig. 3 is a diagram showing the grinding method of the present invention.
FIG. 4 is an enlarged view of the grinding wheel portion of FIG. 3. 1: Rotary table, 1a: Rotation axis center,
2: Workpiece, 3: Grinding wheel, 4: Inner diameter circle of workpiece, 5: Outer diameter circle of grinding wheel.

Claims (1)

[Claims] 1. On a rotary table, place a number of workpieces made of difficult-to-cut non-ferrous metals in an annular shape on the same circumference drawn at a certain distance from the rotation axis of the rotary table. In a grinding method in which multiple workpieces are ground at once using a rotary whetstone that rotates in the opposite direction to the rotation direction, a fixed grinding method is used in which the inner circle drawn by the workpiece as the rotary table rotates is almost in contact with the outer circle of the rotary whetstone. A grinding contact surface is created between the workpiece and the rotating grindstone so that the direction of movement of the workpiece and the rotating direction of the rotating grindstone are in parallel contact with each other at one fixed position, and the rotating grindstone is always in contact with multiple workpieces. With a large surface and low surface pressure, both the rotary table and the rotary grindstone rotate continuously, and the workpiece is ground according to the rotation period of the rotary table 1
A grinding method characterized by being a process.