JPH0523957A - Grinding machine - Google Patents

Abstract

PURPOSE:To provide a grinding machine which is able to a workpiece in a short time when both the ends are ground by one unit alone and improves the extent of concentricity in the workpiece to be ground. CONSTITUTION:The outer circumference of a work 30 is supported at three points, a first driving roller 8, a second driving roller 9 and a keep roller 20. Both axial ends of this work 30 supported at three points are ground by a first grinding wheel 5 and a second grinding wheel 6. In this case, those of first driving roller 8, second driving roller 9 and keep roller 20 are all supported by a hydrostatic bearing each. A spring constant of the hydrostatic bearing for the keep roller 20 is relatively smaller than that of these hydrostatic bearings for both first and second rollers 8 and 9. Accordingly, since a vibration of the keep roller 20 is hard to be transmitted to both these rollers 8 and 9, grinding can be done so accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding machine, and more particularly to a grinding machine for grinding small workpieces such as small parts.

[0002]

2. Description of the Related Art Conventionally, when grinding a work such as a small precision part such as a needle or a nozzle, if the work has a complicated shape or a small work, it is difficult to support the axis of the work. is there. As a grinder for grinding such small work pieces, a driving roller, a pressing roller,
2. Description of the Related Art There is known a device that rotates while positioning the outer periphery of a work with a fixed shoe and grinds with a grinding wheel.

[0003]

According to this conventional grinding machine, when grinding both ends of a work, it is necessary to change the direction of the work and grind with the same grinding machine or another grinding machine having a similar structure. Therefore, there is a problem that interference between the work and the pressing shaft occurs, and unstable work support occurs due to an increase in frictional force between the work and the fixed shoe. Therefore, the concentricity of the processed parts at both ends of the work is reduced, and the processing time is long. When machining a workpiece in a short time, it is conceivable to perform high-efficiency grinding, but in order to do so, it is necessary to increase the pressing force of the presser roller. If this is done, the frictional force will increase, so the pressing force of the presser roller must be increased. However, the driving force of the work cannot be increased, and it is difficult to perform high efficiency grinding.

The present invention has been made in order to solve such a problem, and it is possible to enhance the concentricity of both ends of a workpiece with a single grinding machine and perform grinding in a short time. The purpose is to provide a board.

[0005]

To achieve the above object, a grinding machine according to the present invention is connected to a rotary drive source, supports a first point on the outer circumference of a work, and has a hydrodynamic bearing.
It is connected to the drive roller and the rotation drive source,
A second drive roller that supports a point and has a fluid bearing; a pressing roller that supports a third point on the outer circumference of the workpiece and that has a fluid bearing having a spring constant relatively smaller than the spring constant of the fluid bearing; A first grinding wheel and a second grinding wheel which are provided so as to be able to grind both ends in the axial direction.

[0006]

According to the grinding machine of the present invention, both ends of the work in the axial direction are ground at the same time without replacing the work, so that the working time can be shortened and the coaxiality of the working part of the work can be improved.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the housing 4 of the grinder device 1
A first grinding wheel 5 and a second grinding wheel 6 for grinding both ends of the work are connected to the rotary drive sources 2 and 3, respectively.

As shown in FIGS. 1 and 3, the drive rollers 8 and 9 are provided so that the rotary shafts 12 and 13 are parallel to each other, and the rotary shaft 12 is rotatably supported by a hydrostatic bearing using a working fluid 16. ing. Similarly, the rotary shaft 13 is also supported by a hydrostatic bearing using the working fluid 16. The press roller 20 has a rotary shaft 24 supported by a dynamic pressure bearing using a working fluid 22. The rotary shaft 24 is not connected to the rotary drive source. The pressing roller support lever 32 is used for the work 30.
It is possible to swing about a fulcrum a so as to be able to clamp. Further, the pressing roller supporting lever 32 generates a force for pressing the pressing roller 20 against the work 30 using the spring 34 or the like, and the pressing roller supporting lever 32 can be fixed after pressing with a certain constant force. ing.

Next, the operation will be described. The outer periphery of the work 30 is supported at three points by the drive rollers 8 and 9 and the pressing roller 20. When rotational force is applied to the drive rollers 8 and 9,
Since the work 30 is in contact with the drive rollers 8 and 9, the work 30 is rotated. Further, the work 30 and the pressing roller 2
Since it is in contact with 0, rotational force is also generated in the pressing roller 20. At this time, both ends of the work 30 are ground by the first grinding wheel 5 and the second grinding wheel 6.

The spring constant of the dynamic pressure bearing using the working fluid that axially supports the pressing roller 20 is set to be smaller than the spring constant of the static pressure bearing using the working fluid that axially supports the driving rollers 8 and 9. .. This is because when the spring constant of the press roller 20 is smaller than that of the drive rollers 8 and 9, when the circularity of the surface of the press roller 20 has e _P, as shown in FIG. This is because the vibration is relatively larger than the vibrations of the drive rollers 8 and 9 and the work 30, so that the grinding accuracy is improved. As a result, both ends of the work 30 can be processed by the first grinding wheel 5 and the second grinding wheel 6 without replacing the work 30. Therefore, as compared with the conventional replacement method, both ends of the work are coaxially processed. The degree can be improved. According to the experimental data, in this embodiment, the roundness could be more than doubled as compared with the comparative example using the ball bearing in the bearing portion of the pressing roller.

As another embodiment of the present invention, a dynamic pressure bearing using a working fluid can be used for the bearing portion of the drive roller, and a static pressure bearing using a working fluid can be used for the bearing portion of the pressing roller. You can also Generally, when the bearing part of the presser roller is axially supported by a static pressure bearing or a dynamic pressure bearing that uses a working fluid, the presser roller and the presser support lever are not in contact.
As shown in FIG. 4, an amplitude ΔS _p (acceleration α
_When the vibration of ₁ ) occurs, the force acting on the work and the drive roller becomes (mass of the presser roller) x α ₁ , and the force is as small as the mass of the presser roller support lever. for that reason,
Since the vibration ΔS _m of the work and the pressing roller has a smaller amplitude than that when a ball bearing is used for the bearing portion of the pressing roller, the work can be accurately processed.

[0012]

As described above, according to the grinding machine of the present invention, when both ends of the work are ground, the work can be performed by a simple operation without changing the direction and position of the work with a single grinding machine. There is an effect that both ends of the can be quickly and accurately ground.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a main part of a grinding machine according to an embodiment of the present invention.

FIG. 2 is a partially transparent perspective view showing a grinding machine according to an embodiment of the present invention.

FIG. 3 is a partially cutaway arrow view in the direction of arrow A shown in FIG.

FIG. 4 is a diagram for explaining a spring constant of a dynamic pressure bearing of a pressing roller.

[Explanation of symbols]

 5 First Grinding Wheel 6 Second Grinding Wheel 8 First Driving Roller 9 Second Driving Roller 16 Working Fluid (Fluid Bearing) 20 Holding Roller 22 Working Fluid (Fluid Bearing) 30 Workpiece

Claims (1)

Claim: What is claimed is: 1. A first drive roller connected to a rotary drive source for supporting a work outer peripheral first point and having a fluid bearing, and a rotary drive source connected to a work outer peripheral second point. A second drive roller that supports and has a fluid bearing; a pressing roller that supports the work outer peripheral third point and that has a fluid bearing having a spring constant relatively smaller than the spring constant of the fluid bearing; A grinding machine comprising: a first grinding wheel and a second grinding wheel that are provided so that both ends in the direction can be ground.