JP2000126910A - Diaphragm coupling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent exertion of influence on high accuracy (circularity) even if concentricity of a main spindle and an auxiliary spindle get out of order by immovably supporting the central part of a diaphragm in a fixed position by a coupling device main body through a sphere. SOLUTION: A diaphragm 3 is deformed at grinding work time, but since a contact point of the diaphragm 3 and a sphere 4 can not move, in shaft directional displacement of the center of the diaphragm 3, shaft directional rigidity restricted by the sphere 4 is high, and since a central position of the diaphragm 3 is fixed, a posture of a work 15 is statically determined, so that circularity at grinding work time of the work 15 is improved. The work 15 hardly receives the moment caused by an alignment error of a main spindle and an auxiliary spindle since the work can easily swing with a contact point with the sphere 4 as the center. Since the contact point of the diaphragm 3 with the sphere 4 becomes a fixing point, rigidity to the moment can be uniformized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm coupling device used for processing a cylindrical object with high precision using a cylindrical grinder, a lathe or the like.

[0002]

2. Description of the Related Art Conventionally, when processing a cylindrical object with a cylindrical grinder, a lathe, or the like, a chuck device or a center is used to fix a work (object to be processed) that is a cylindrical object. .

[0003]

In turning, cylindrical grinding, and the like, cutting and grinding are performed while rotating a work. However, in order to obtain a perfect circle, it is indispensable to rotate the supported work accurately. Also, in machining, since a machining force is always generated between the work and the tool, not only the rotation accuracy but also the rigidity of the cutting system tool must be increased and the support rigidity must be uniform over the entire circumference of the work. It cannot be processed in a circle.

At present, it is difficult to increase the supporting rigidity in the center processing which is most frequently performed, and self-excited vibration generally known as "chatter" is likely to occur. Further, since the rotation accuracy also depends on the machining accuracy of the center hole, it is difficult to obtain a highly accurate perfect circular shape. Further, it is difficult to keep the quality uniform.

As another supporting method, there is a method in which an auxiliary spindle is used instead of the tailstock and both ends of the work are chucked. In this case, a scroll chuck device is usually used. However, if the number of claws for gripping the work is as small as about three, there is a difference in rigidity between the direction in which the claws exist and the direction in which the claws do not exist. Cannot be cut into a perfect circle.
Even when the number of the claws is as large as four or six, if the alignment of the main spindle and the auxiliary spindle is not correct because the workpiece is strongly gripped, the influence is also exerted. It is difficult to obtain a perfect circular shape.

In order to avoid the influence of the above-described alignment error, a chuck device capable of releasing a moment may be used. For this purpose, a diaphragm chuck device may be used. Since the center of the swing is not determined, the posture of the work becomes unstable, and it is also difficult to obtain a perfect circular shape.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide high rigidity in the radial and axial directions and low rigidity against bending moment. It is another object of the present invention to provide a diaphragm coupling device having no directionality with respect to rigidity.

[0008]

According to a first aspect of the present invention, there is provided a diaphragm coupling device in which a diaphragm is mounted on a coupling device main body. It is characterized in that the coupling device body is immovably supported via a sphere at a fixed position.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a configuration of a diaphragm coupling device according to an embodiment of the present invention.
In the figure, reference numeral 1 denotes a diaphragm coupling device, and the diaphragm coupling device 1 includes a coupling device main body 2, a diaphragm 3, and a sphere 4 as main components.

The coupling device main body 2 is composed of two circular disks 2a and 2b. One circular disk 2a is fixed to one end surface of a rotary spindle 5 provided in a processing device such as a grinding machine by bolts 6. I have. The other circular disk 2b is provided with a bolt 7 on one end surface of the one circular disk 2a.
It is fixed by.

The diaphragm 3 is connected to the other circular disk 2b.
Is disposed on one end face side of the. An outer peripheral portion of the diaphragm 3 is held by an outer peripheral portion of one end surface of the other circular disk 2 b and an annular diaphragm retainer 8 and fixed by bolts 9. The two circular disks 2a, 2a
b is fixed to the other circular disc 2b
Also serves as a bolt for fixing the diaphragm 3 and the diaphragm retainer 8. The dimensions of the sphere 4 are selected so that the bolt 9 can be tightened to apply a preload to the sphere 4 for abutment of the diaphragm 3 on the sphere 4. This is necessary to ensure axial rigidity.

The center of both sides of the diaphragm 3 is sandwiched between two circular plates 10 and 11. One circular plate 10 has an annular shape. The diaphragm 3 and the two circular plates 10 and 11 are fixed to each other by bolts 12 inserted from one of the circular plates 10. One circular plate 10
And the other circular disk 2b, the diaphragm 3
Is provided to such an extent that is inclined. A connecting member (mounting spacer) 13 is fixed to one side surface of the other circular plate 11 by a bolt 14. One end of a work 15 is fixed to the connecting member 14 by bolts 16. As illustrated, the diaphragm 3 applies a preload to the sphere 4 when the workpiece 15 is fixed to the diaphragm coupling device 1.

The sphere 4, which is the gist of the present invention, is disposed between the center of the other circular disk 2b and the center of the diaphragm 3. The sphere 4 is housed in a conical concave portion 17 formed at the center of one side surface of the other circular disk 2 b, and is in point contact with the center of the diaphragm 3. The point of contact between the diaphragm 3 and the sphere 4 does not move (position does not change) no matter how the diaphragm 3 bends. Therefore, the central part of the diaphragm 3
The coupling device main body 2 is immovably supported at a fixed position via a sphere 4 at the center of the other circular disk 2b.

FIG. 2 is a partially cutaway plan view showing a schematic configuration of a grinding machine provided with a diaphragm coupling device 1 according to an embodiment of the present invention on a spindle spindle 23 side and an auxiliary spindle 24 side, respectively. It is. In the figure, reference numeral 20 denotes a grinding machine, and a table 2 is placed on a bed 21 thereof.
2 is mounted and fixed. The table 22 is provided with a main spindle spindle 23 and an auxiliary spindle 24 for supporting the work 15 and a main spindle drive motor 25 for generating a rotational output for rotating the work 15.

The main spindle 23 is provided with a main shaft 23a (corresponding to the rotary main shaft 5 in FIG. 1) to which one end of the work 15 is mounted via the diaphragm coupling device 1 of the present invention, and rotatably supports the main shaft 23a. And a first hydrostatic fluid bearing 23b.
A first bearing cap 23c is fixed to one end of b by a plurality of first cap bolts 23d. A plurality of static pressure pockets 23e are provided on the inner peripheral surface of the bearing 23b, and the main shaft 23a is moved by the fluid such as air or oil supplied through the static pressure pocket 23e.
b is supported so as to be rotatable in the radial direction in a non-contact state with the inner peripheral surface of b.

At least one annular static pressure pocket 23f, 23f 'is provided on each of the opposed end faces of the bearing 23b and the first bearing cap 23c. A first thrust collar 23g is provided on the outer periphery. The main shaft 23a is in a non-contact state with each end face of the bearing 23b and the first bearing cap 23c through the first thrust collar 23g by a fluid such as air or oil supplied through the static pressure pockets 23f, 23f '. It is supported in the axial direction.

Further, the main shaft 23a has a first end for mounting the diaphragm coupling device 1 of the present invention on one end surface.
And a second protrusion 23h on the other end surface.
i, and an output shaft 25 of a spindle drive motor 25 via a coupling 26 connected to the second protrusion 23i.
a.

The auxiliary spindle 24 used for supporting and working the work 15 at both ends is provided with an auxiliary shaft 24a to which the other end of the work 15 is mounted via the diaphragm coupling device 1 of the present invention, and the auxiliary shaft 24a. And a second hydrostatic bearing 24b rotatably supporting the bearing 24a. A second bearing cap 24c is fixed to one end of the bearing 24b by a plurality of second cap bolts 24d. A plurality of static pressure pockets 24e are provided on the inner peripheral surface of the bearing 24b, and the auxiliary shaft 24a is moved by the fluid such as air or oil supplied through the static pressure pocket 24e. It is supported so as to be able to rotate in the radial direction without contacting the surface.

The bearing 24b and the bearing cap 24c
At least one annular static pressure pocket 24f, 24f 'is provided on each of the opposed end faces of
Correspondingly, a second thrust collar 24g is provided on the outer periphery of the auxiliary shaft 24a. The auxiliary shaft 24a is in a non-contact state with each end face of the bearing 24b and the second bearing cap 24c via the second thrust collar 24g by a fluid such as air or oil supplied through the static pressure pockets 24f, 24f '. Is supported in the axial direction. Further, the auxiliary shaft 24a has a third protrusion 24h for attaching the diaphragm chuck device 1 to one end surface.

On the bed 21, a grindstone table 27 is provided so as to be movable in the axial direction of the work 15 and in a direction perpendicular to the axial direction (the direction of the arrow in FIG. 2). A grindstone drive motor 28 is mounted and fixed. A grinding wheel 29 is fixed to an output shaft 28a of the grinding wheel drive motor 28. By moving the grindstone table 27 on the bed 21 in the direction of the arrow (length and width), the grindstone 29 is moved to the work 15.
Cuts and feeds a specified width in the radial direction of
Traverse in the axial direction of No. 5 with a predetermined width.

At predetermined locations on the inner peripheral surfaces of the bearings 23b and 24b, annular grooves 30 and 31 for allowing fluid to escape are provided.

Next, the diaphragm coupling device 1 having the above configuration is mounted on a main spindle 23 and an auxiliary spindle 24 of a grinding machine 20 as shown in FIG. 2, respectively, and these diaphragm coupling devices 1 and 1 are used. To support the work 15. And the spindle drive motor 2
5, the spindle spindle 23 is driven to rotate, and the work 15 is rotated.
By rotating the grindstone 29 by the grindstone drive motor 28 and moving the grindstone table 27 by a required amount in the direction of the arrow in the figure, the work 15 is ground by the grindstone 29 into a circular shape.

In such a grinding process, in the case of the conventional diaphragm chuck device, the center of the diaphragm is deformed irregularly (due to poor gripping alignment of both diaphragm chuck devices) due to deformation of the diaphragm. Therefore, the deflection in the radial direction of the axis of the diaphragm deteriorates the roundness at the time of grinding the workpiece.

On the other hand, in the case of the diaphragm coupling device 1 according to the present embodiment during grinding, the diaphragm 3 is deformed, but the contact point between the diaphragm 3 and the sphere 4 cannot be moved. Since the axial displacement of the center of the diaphragm 3 is high in the axial rigidity restrained by the sphere 4, and the position of the center of the diaphragm 3 is fixed, so that the posture of the work 15 becomes static,
The roundness of the work 15 at the time of grinding is improved.

When grinding is performed while supporting the work using a normal scroll chuck device, the main spindle 23 and the auxiliary spindle 24 are used to strongly grip the work.
Is out of alignment, the rotation accuracy of the spindles 23 and 24 is degraded due to the influence, or the work is deformed during processing, and it is difficult to obtain high roundness.

On the other hand, in the diaphragm coupling device 1 according to the present embodiment, the work 15 (and the diaphragm 3 to which the work 15 is fixed) can easily swing around the point of contact with the sphere 4. Spindle 2
3 and the moment caused by the alignment error of the auxiliary spindle 24 is not easily received.

In the conventional diaphragm chuck device, the behavior of the workpiece cannot be predicted because the deformation mode of the diaphragm is not constant. However, in the diaphragm coupling device 1 according to the present embodiment, Since the point of contact with the sphere 4 is a fixed point, the rigidity against the moment is uniform in any direction.

At this time, since the amount of deformation of the diaphragm 3 due to bending is extremely small, the radial force generated by the processing is received by the in-plane deformation of the diaphragm 3, and high rigidity is obtained. Its stiffness is uniform in any direction.

When the diaphragm coupling device 1 according to this embodiment is used for both the main spindle 23 and the auxiliary spindle 24 of the grinding machine 20 as shown in FIG. 2, the main spindle 23 and the auxiliary spindle 24 are intentionally used.
When the workpiece 15 was ground with the coaxiality shifted, the circularity was not affected even when the coaxiality was shifted by 0.1 mm at a distance of 200 mm between the center axes of the main spindle spindle 23 and the auxiliary spindle 24. Was.

In the conventional diaphragm chuck device, since the processing force in the axial direction is applied perpendicularly to the diaphragm surface, the rigidity is low, which causes "chatter" when grinding the end surface of the work.

However, according to the diaphragm coupling device 1 according to the present embodiment, since the spherical body 4 receives the machining force in the axial direction, the rigidity caused by the deformation of the spherical body 4 is increased in addition to the rigidity of the diaphragm 3 in the axial direction. And high rigidity can be obtained.

FIG. 3 shows a work (for example, a work piece) obtained by performing grinding using the diaphragm coupling device 1 according to the present embodiment for both the main spindle spindle 23 and the auxiliary spindle 24 as shown in FIG. Diameter 50mm, length 2
(00 mm) is a diagram showing a roundness of 15. The roundness in this case is 0.03 μm and 30 nm.

FIG. 4 is a diagram showing a graph of FIG.
It is a figure showing the roundness of the work obtained by performing grinding using the scroll chuck device which has two nails. The roundness in this case is 0.34 μm and 340 nm.

In the case of FIG. 4, the roundness is lower than in the case of FIG. 3 because the moment is supported, so that it is affected by the coaxiality of the main spindle spindle 23 and the auxiliary spindle 24. This is probably because the radial rigidity has directionality.

FIG. 5 is a view showing the roundness of a workpiece obtained by performing grinding using a conventional diaphragm chuck device under the same conditions as in FIG. The roundness in this case is 0.14 μm and 140 nm.

In the case of FIG. 5, the roundness is worse than in the case of FIG.
Although the influence of the coaxiality is slight, it is considered that the center of the diaphragm is displaced indefinitely and its deformation mode is not constant, so that the radial rigidity has directionality.

Further, in the above-described embodiment, the work 1 is connected to the diaphragm coupling device 1 by using the bolt 16.
5, the present invention is not limited to this, and the work 15 may be attached to the diaphragm coupling device 1 using a gripping claw without using the bolt 16.

The diaphragm coupling device 1 of the present invention is not only used for the grinding machine 20 having the configuration shown in FIG. 2 described above, but is widely used for a processing device for grinding the work 15 into a circular shape. It is possible to apply.

[0040]

As described above in detail, according to the diaphragm coupling device of the present invention, when the workpiece is used for machining with both ends supported, no moment is supported, so that the coaxiality of the main shaft and the auxiliary spindle is reduced. Even if it is out of order, there is an effect that the processing accuracy (roundness) is not affected.

Further, since the rigidity has no directionality and the rigidity is high, there is an effect that processing with a high roundness, for example, a roundness of 0.1 μm or less can be performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a diaphragm coupling device according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway plan view showing a configuration of a grinding machine provided with the diaphragm coupling device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a roundness of a grinding example when the diaphragm coupling device according to the first embodiment of the present invention is used.

FIG. 4 is a diagram showing roundness of a grinding example when a scroll chuck device is used.

FIG. 5 is a diagram showing roundness of a grinding example when a conventional diaphragm chuck device is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diaphragm coupling device 2 Coupling device main body 2a Circular disk 2b Circular disk 3 Diaphragm 4 Sphere 5 Rotating main shaft 6 Bolt 7 Bolt 8 Diaphragm holding 9 Bolt 10 Circular plate 11 Round plate 12 Bolt 13 Connecting member (Mounting spacer) 14 Bolt 15 Workpiece (material to be ground) 16 Bolt 17 Concave part 20 Grinding machine 21 Bed 22 Table 23 Main spindle 23a Main spindle 23b First hydrostatic bearing 23c First bearing cap 23d First cap bolt 23e Static pressure pocket 23f Static pressure Pocket 23f 'Static pressure pocket 23g First thrust collar 23h First protrusion 23i Second protrusion 24 Auxiliary spindle 24a Auxiliary shaft 24b Second hydrostatic bearing 24c Second bearing cap 24d Second cap bolt G 24e Static pressure pocket 24f Static pressure pocket 24f 'Static pressure pocket 24g Second thrust collar 24h Third projection 25 Main shaft drive motor 25a Output shaft 26 Coupling 27 Wheel head 28 Wheel drive motor 28a Output shaft 29 Grindstone 30 Ring groove 31 annular groove

Claims (1)

[Claims] 1. A diaphragm coupling device having a diaphragm mounted on a coupling device main body,
A diaphragm coupling device, wherein a central portion of the diaphragm is immovably supported at a fixed position via a sphere at a fixed position on the coupling device main body.