JP2583005B2 - Abrasive center - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center with abrasives for rotatingly supporting a workpiece in a grinding device, a cutting device, or the like. More specifically, by correcting an error such as the shape of the center hole at both ends of the work to be rotated and supported at the beginning of rotation, a grinding device and a cutting device (hereinafter, referred to as a work machine) for the work can be obtained.
Center represented by a grinding device), that is, a center with abrasive grains capable of eliminating rotational runout.

[0002]

2. Description of the Related Art Generally, when a high-precision finishing process such as polishing is performed on the outer peripheral surface of a workpiece, a center support method is used as a method of supporting the workpiece.

In this center supporting method, a workpiece having a conical center hole formed at the center of both end faces is supported from both sides of the workpiece by a center attached to a grinding device. An error in the shape and size of the center hole due to deformation or distortion (for example, a perfect circle changes to an ellipse) causes misalignment, resulting in rotational runout of the workpiece and a reduction in machining accuracy. Become.

Conventionally, it is conceivable to increase the machining allowance of a workpiece in consideration of the amount of rotational run-out in advance, but this is because the yield of material is poor and the processing time is long, so that the workpiece is processed before polishing. The object is mounted on a processing machine of the outside diameter chuck type different from the grinding machine, and after centering using the dial cage, processing the sheet surface to correct the shape error of the center hole, and then polishing. I was

[0005]

However, the conventional sheet surface processing is performed by a device different from a grinding device for finish polishing, so that a workpiece is attached to and detached from a device.
It also required very troublesome work such as alignment with the device at the time of installation. Therefore, the cost is high due to the necessity of such a process and the inevitable misalignment caused by changing the apparatus, and the finishing accuracy can be as small as 0.003 to 0.005 mm as the center deflection width. There was no problem.

In general, it is desirable to perform all the operations performed while rotating the workpiece in a single apparatus from the viewpoint of reducing the number of steps and preventing misalignment.

The present invention has been made in view of the above circumstances, so to speak, a center with abrasive grains which can simultaneously perform, as it were, sheet surface processing and finish polishing of the center hole of a workpiece by the same apparatus by one operator. It is intended to provide.

[0008]

The center with abrasive grains of the present invention is a center for rotatably supporting both ends of a workpiece in a processing apparatus, and can be in sliding contact with a center hole of the workpiece. At least on the tapered surface at the top , as abrasive grains
It is characterized in that abrasive grains are adhered while leaving the action .

[0009]

According to the center with abrasive grains of the present invention, since the leading portion is in sliding contact with the center hole of the workpiece which is rotatably supported, even if the leading portion is flattened due to an error in the shape of the center hole, etc. During the rotation, the sheet surface of the center hole is corrected by the abrasive action of the abrasive grains of the center, so that the sheet perfectly follows the shape of the head of the center.

As a result, the conventional sheet surface processing step is omitted, and the work of aligning the work to be attached to another device can be omitted, so that the workability is greatly improved and the cost can be reduced.

Further, since the correction is performed simultaneously with the support of the workpiece in the final finishing device, the rotational vibration of the workpiece is almost eliminated, and the processing accuracy is improved.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a center with abrasive grains according to the present invention.

FIG. 1 is a front view showing one embodiment of the center with abrasive grains of the present invention, FIG. 2 is a front view showing another embodiment of the center with abrasive grains of the present invention, and FIGS. FIG. 5 is a perspective view showing still another embodiment of the center with abrasive grains of the present invention, and FIG. 5 is an explanatory view showing center support of a workpiece to a processing device.

As shown in FIG. 1, as shown in FIG.
Like a known center, 1 connects a conical head portion 2 at the front end, a shank portion 3 slightly tapered at the rear end, and the front portion 2 and the shank portion 3. And a neck portion 4. The tip angle of the head 2 is generally selected from a range of 60 to 90 degrees. The material of the center is S45C, SK-3, stainless steel, or the like, and its surface is given a desired hardness by heat treatment.

According to the present invention, abrasive grains 5
The feature is that is attached.

The abrasive grains 5 are made of a substance having a high hardness and a high melting point, such as diamond abrasive grains, CBN (cubic boron nitride) abrasive grains, and tungsten abrasive grains, either as a single substance or as a mixture. The type of abrasive grain is selected depending on the properties of the workpiece, such as whether or not quenching is performed. The grain size of the abrasive grains 5 is, for example, 0.3 mm as # 60, # 1
One suitable for the processing can be selected from a wide range, such as 0.15 mm for 00 and 0.1 mm for # 140.

The attachment of the abrasive grains 5 is performed by an electrodeposition method. The point is that the abrasive grains 5 need only be uniformly and firmly attached, and the invention is not particularly limited to the electrodeposition method. As described above, since the center with abrasive grains can be obtained by manufacturing a commercially available center, it is relatively inexpensive.

Next, FIG. 2 shows another embodiment of the center of the present invention.

The center 6 differs from the center 1 of the embodiment (FIG. 1) only in its shape.
Is a large one composed of a conical portion 7 and a cylindrical portion 8.

The center 6 is mainly used for a pipe or a solid material having a large center hole and a small difference between the outer diameter and the center hole diameter.

The center 9 shown in FIG.
A plurality of vertical grooves 11 are formed on a zero tapered surface (the number is not limited). The shavings of the workpiece, which have been removed by the abrasive grains 5, are discharged to the outside by the vertical grooves 11, so that the processing accuracy is further improved.

The center 12 shown in FIG. 4 has a spiral groove 14 formed on a tapered surface of a leading portion 13 thereof. This groove 14 is not particularly limited to one,
It may be more than books. With this spiral groove 14,
An effective shavings discharge effect similar to that of a drill blade is exhibited.

Next, the support and operation of the centers 1 and 6 (hereinafter, represented by 1) will be described with reference to FIGS.

A center hole H is formed at the center of both ends of the columnar workpiece W. The head 2 of the center 1 fixed to the grinding device is fitted into the center hole H, and the workpiece W is supported from both ends.

The workpiece W is rotated by a rotation applying mechanism 15 provided in the grinding device. This rotation applying mechanism 1
Reference numeral 5 denotes a rotating plate (generally called a clipper) 16 for transmitting a rotating force, and a turner fixed to one end of the workpiece W and rotated by the rotating plate 16 (generally called a vignetting). 17.

On the workpiece W, the rotation applying mechanism 15
The grindstone 18 is arranged so as to be able to rotate at a position where it does not interfere with the grinding wheel. The grindstone 18 can move parallel to the workpiece W in the axial direction as it advances and retreats to the workpiece W.

When the workpiece W is rotated for a while by the rotation applying mechanism 15, the center 1 is fixed, so that the abrasive grains 5 slide on the sheet surface S of the center hole H to polish the center. This polishing operation corrects a shape error or the like of the center hole H, and the center hole H follows the shape of the head portion 2. Thereby, since the rotational runout of the workpiece W caused by the shape error of the center hole H is suppressed to be small, it is possible to improve the accuracy of the subsequent polishing by the grindstone 18. That is, the center runout of the workpiece in the roughing stage before the polishing performed by using the center 1 is ± 0.0%.
It has been proved by an experiment that if the thickness is within 2 mm, the run-out is completed in the range of about 0.002 to 0.004 mm by the main polishing.

The case where the center of the present invention is applied to the polishing of a solid material has been described above. However, the center of the present invention is sufficiently used for cutting other than polishing, which requires high precision. be able to.

Even if the abrasive grains are worn, they can be attached many times without repairing the head portion, so that it is economical.

[0030]

Since the center with abrasive grains of the present invention corrects the shape error of the center hole at the same time as supporting the rotating workpiece, the conventional sheet surface processing can be omitted and the workability can be improved. . In addition, since the polishing and the like are continued with the same device after the correction, the processing accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a center with abrasive grains of the present invention.

FIG. 2 is a front view showing another embodiment of the center with abrasive grains of the present invention.

FIG. 3 is a perspective view showing still another embodiment of the center with abrasive grains of the present invention.

FIG. 4 is a perspective view showing still another embodiment of the center with abrasive grains of the present invention.

FIG. 5 is an explanatory diagram showing center support of a workpiece to a processing device.

[Explanation of symbols]

 1, 6, 9, 12 Center 2, 10, 13 Head 5 Abrasive

Claims (1)

(57) [Claims] 1. A center for rotatably supporting both ends of a workpiece in a processing apparatus, wherein at least a tapered surface of a leading portion which can slidably contact a center hole of the workpiece is ground.
A center with abrasive grains to which abrasive grains are adhered while retaining the action of the grains.