JPH09323217A - Thread groove grinding time supporting device of long work and supporting method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately perform the thread groove grinding of a long work to be a ball screw, etc., regardless of the rigidity, the roundness of the outside diameter and the dimension, etc., of the work. SOLUTION: The device is provided with a work rest 3 supporting the internal surface of the thread groove (a) of a long work W opposite to a grinding wheel 2. The work rest 3 supports the internal surface of the thread groove by a ball shaped member 10. The ball shaped member 10 is made to freely move in the axial direction in a small range to absorb a lead error due to a self-aligning and to support the ground portion of the thread groove (a).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supporting device and a supporting method for supporting a work when grinding a thread groove on a work having a large length dimension with respect to a diameter dimension such as a screw shaft of a ball screw. .

[0002]

2. Description of the Related Art When grinding a thread groove of a long work such as a ball screw, the work is bent by a working force and its own weight only by supporting both ends of the work at a center. In order to prevent such bending, work rests that support a plurality of workpieces in the longitudinal direction at fixed positions have been used. FIG. 4 (A) is a vertical cross-sectional view of a conventional work rest mounted on a grinder, and FIG. 4 (B) is a schematic plan view of a work support state by the work rest. W is work, 32
Is a grindstone, and 33 is a work rest arranged on the side of the workpiece W facing the grindstone 32. These work rests 33 include three claws 36a to 36a installed on the fixed base 34.
The outer diameter surface of the work W is supported by 36c. Reference numeral 37 is a work spindle, and 38 is a support member that supports the centers of both ends of the work.

[0003]

However, in this supporting method, the bending amount of the work W differs between the support positions of the respective work rests 33 and between the support positions, and the thread groove is machined to have the same diameter over the entire length of the work W. Difficult to do. for that reason,
It is necessary to increase the number of micro cuts or spark outs in the finishing process. Further, since the work rest 33 supports the work W by its outer diameter surface, the groove bottom diameter of the screw groove is greatly affected by the roundness and diameter of the work outer diameter, and the relationship between the outer diameter portion and the groove bottom diameter is large. Since the groove grinding is performed while continuously changing in the axial direction, the roundness is also adversely affected. In the ball screw, the outer diameter surface is functionally left as it is as a so-called black skin with heat treatment applied (except for the sealing property), but as described above, the outer diameter surface affects the groove bottom diameter.
In order to achieve high accuracy, it is necessary to machine the outer diameter surface as well, which increases the cost.

The present invention solves such a problem and provides a long work piece which can finish the thread groove of the long work piece with an equal diameter and good cylindricity without being affected by the shape and size of the outer diameter surface of the work piece. An object of the present invention is to provide a supporting device and a supporting method when grinding a thread groove. Another object of the present invention is to allow the lead to be used for grinding different thread grooves, and to enable the support of the proper position to be obtained by a self-aligning action in order to correct a subtle error of the lead. Is.

[0005]

SUMMARY OF THE INVENTION A support device for thread groove grinding of a long work according to the present invention comprises a pair of end support members for supporting centers of both ends of a long work having a thread groove on the outer periphery,
It is provided with a work rest that faces a grindstone that grinds a thread groove of a long work supported by the end support member and that supports a thread groove curved surface. When the work rest is fed by moving the grindstone, the workrest is moved together with the grindstone. According to this configuration, the long work is always supported by the work rest at the axial position closest to the grindstone in the thread groove, and is ground while being sandwiched between the workrest and the grindstone. Therefore, the work rest is prevented from bending due to processing force and the like, and grinding is performed while maintaining the groove diameter at a dimension regulated by the grindstone and the work rest. Therefore, the inside of the groove can be finished to have the same diameter along the entire length in the axial direction, and the inside of the groove can be finished without being affected by the accuracy of the outer diameter surface of the work.

In the above structure, the work rest includes a ball-shaped member that comes into contact with the curved surface of the thread groove of the work and a ball support member that movably supports the ball-shaped member in the axial direction of the work within a predetermined range. May be In this configuration, when there is a difference in the lead of the screw groove depending on the work, for example, even in the state of black skin immediately after quenching, the position of the ball-shaped member is automatically adjusted so as to always contact the curved surface of the screw groove. Since, so to speak, self-centering action is obtained, it is possible to improve the grinding accuracy of the thread groove without being affected by the difference in the leads. Further, in the above configuration, the pair of end portion support members support a long work substantially horizontally, the grindstone and the workrest are arranged so as to face substantially horizontally, and long in the vicinity of the grindstone. A lower surface support member that supports the outer diameter surface of the length work from below may be provided. The lower surface support member is used as a support or the like for placing a long work piece at the time of setup change and the like, and convenience of setup change and the like is obtained. Since the work rest is supported by the working force of the grindstone, even if the lower surface supporting member is in contact with the outer diameter surface of the long work, the work can be reliably supported without lowering the accuracy of the groove processing.

According to the method of supporting a long work for grinding a thread groove of the present invention, the center of both ends of a long work having a thread groove on the outer periphery is supported, and a thread groove curved surface several turns from the end portion of the work is rested. And a step of grinding the remaining portion of the thread groove curved surface while supporting the ground portion of the thread groove curved surface with a work rest facing the grindstone. Even for long workpieces, the rigidity of the shaft end is high, so sufficient grinding is possible without a work rest. Before the start of grinding, there are many cases where the long work does not have a position with sufficient accuracy to support it with the work rest.Grinding without the work rest in this way gives good accuracy without being affected by the work rest. Can be processed. After that, the grinding is continued while supporting the inside of the groove whose accuracy is secured by the grinding with the work rest, and the grinding can be performed with higher accuracy.

Also in this screw groove grinding supporting method, the work rest may support the curved surface of the screw groove by a ball-shaped member movably supported in the axial direction of the work. As a result, similarly to the above, even if there is a difference in the lead of the thread groove depending on the long work, the proper position in the groove is supported by the work rest by the centering action, and accurate grinding is performed. In the support method for these thread grooves,
After grinding the remaining portion of the thread groove curved surface, the outer diameter surface of the long work may be ground concentrically with the thread groove while the work groove supports the thread groove curved surface. As a result, the outer diameter surface of the long work can be accurately and concentrically formed with the thread groove curved surface. In this case, the grinding device that grinds the thread groove is provided with a grindstone for grinding the outer diameter and a grindstone for the outer diameter grinding, separately from the grindstone for grinding the thread groove, and supports both ends of the long workpiece after grinding the thread groove. It is preferable to continuously grind the outer diameter surface without removing.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 (A) and 1 (B) are a plan view and a side view showing a main part of a grinder equipped with a support device for this thread groove grinding. The support device for this thread groove grinding is
A pair of end supporting members (for example, centers) 1 and 1 for horizontally supporting the long work W having the thread groove a on the outer periphery at the centers of both ends as shown in the plan view of FIG. 2, and this end supporting member 1
The work rest 3 for supporting the curved surface of the thread groove a of the long work W supported by the above-mentioned in opposition to the grindstone 2. Of the pair of end supporting members 1 and 1, one end supporting member 1 is mounted on the work spindle 4 and the other end supporting member 1 is provided.
Is equipped on a tailing shaft (not shown). In the axial feed of the grindstone 2 to the work W, the work spindle 4 and the centering shaft may be installed on a common moving table (not shown) to move the work W side.
Alternatively, the whetstone 2 may be moved with the position fixed. In the case of the configuration in which the grindstone 2 is moved, the workrest 3 is installed on a moving table (not shown) common to the grindstone stand so that the workrest 3 can move together with the grindstone.

As shown in FIG. 1, a horizontal slide base 6 is provided so as to be slightly movable in the axial direction (Z-axis direction) of the long work W with respect to the main body frame 5 of the grinding machine. The position can be adjusted by an adjusting screw 9 provided at the position 5. A lower surface support member 7 for supporting the long work W from below is provided on the horizontal slide base 6 in the vicinity of the grindstone 2. The lower surface support member 7 has a V-groove shaped support surface 7a, and supports the long work W in contact with two points on the outer diameter surface. The height of the lower surface support member 7 can be adjusted by an adjusting screw 8.

As shown in FIG. 3, the work rest 3 is a ball-shaped member 10 which comes into contact with the curved surface of the thread groove a of the long work W.
And a ball supporting member 1 for supporting the ball-shaped member 10.
1 is provided. The ball support member 11 is the ball-shaped member 1
Support groove 11 for accommodating 0 movably in the axial direction of the work W
The ball-shaped member 10 has a and is freely movable by rolling within a predetermined range regulated by the support groove 11a. The work rest 3 has its advancing position adjusted in the direction perpendicular to the Z-axis direction (X-axis direction) by the approach amount adjusting device 12 installed on the horizontal slide base 6 in FIG. The approach amount adjusting device 12 includes a ball screw 14 supported by a bearing 13 on a horizontal slide base 6, a work rest base 16 connected to the ball screw 14 via a ball nut 15, and a screw drive mechanism 17. Composed of. The work rest base 16 is supported on the horizontal slide base 6 by a guide member (not shown) so as to be movable back and forth. The screw drive mechanism 17 is the servo motor 1 provided on the horizontal slide base 6.
8, a speed reducer (worm gear) 20 connected to the output shaft of the motor 18 via a coupling 19, and a worm wheel 21 provided on the ball screw 14 and meshing with the worm gear 20.

The screw groove grinding operation with the above configuration will be described. The long work W supports the centers of both ends with a pair of end support members 1 and 1. At this time, the lower surface support member 7 is used as a platform on which the long work W is temporarily placed. When replacing the long work W with a diameter different from that at the time of the previous processing, such as when changing lots, the height of the lower surface support member 7 is adjusted by the adjusting screw 8 according to the outer diameter of the work. Further, the position of the horizontal slide base 6 in the X-axis direction is adjusted by the adjusting screw 9 according to the lead of the thread groove a of the long work W so that the ball-shaped member 10 of the work rest 3 comes into contact with an appropriate position. The work rest 3 waits at a position apart from the long work W at the end of the long work W before the start of grinding.

In this way, the curved surface of the thread groove a is ground from one end of the long work W while the long work W is rotated by the work spindle 4 and the grindstone 2 is rotated. At the time of this grinding, the first several turns of the thread groove a are ground only by supporting both ends without being supported by the work rest 3. In the portion near the end, the long work W has high rigidity and the long work W is less likely to be bent by the grinding force of the grindstone 2. Therefore, the thread groove a can be ground with high accuracy without the work rest 3.

After grinding the thread groove a for several turns, the approach amount adjusting device 12 is driven to support the portion of the curved surface of the thread groove a of the long work W immediately after grinding by the ball-shaped member 10. In this supporting state, the remaining portion of the thread groove a is ground. The amount of advance of the work rest 3 is automatically adjusted based on previously input data such as a difference in shaft diameter of the replaced long work W or a difference in depth of the thread groove a. Thus, the curved surface of the thread groove of the workpiece W facing the grindstone 2 is supported by the work rest 3, and the thread groove a is ground while keeping the distance between the ball-shaped member 10 of the work rest 3 and the grindstone 2 constant. Because it will be
While preventing the long work W from bending during grinding, the thread groove a
Can be ground to a constant groove diameter. Further, since the ground portion of the thread groove a is supported, the grinding can be performed with high accuracy without being affected by the shape and size of the outer diameter surface of the long work W. For this reason, the long workpiece W before grinding can be accurately finished with the thread groove a regardless of whether it is a heat-treated black leather or a rolled product. . Therefore, productivity can be improved and cost can be reduced.

Further, the ball-shaped member 10 of the work rest 3
Is a long work W in the support groove 1a of the ball support member 11.
Since it is movable in the axial direction, even if there is a slight difference in the lead of the thread groove a of the long work W to be replaced, the error is automatically absorbed and the ball is always placed at the appropriate position on the curved surface of the thread groove. The member 10 is in contact. Therefore, the thread grooves a of various leads of the long work W can be accurately ground without causing a problem of misalignment.

After grinding the remaining portion of the thread groove a, the outer surface of the long work W is concentric with the thread groove while supporting the curved surface of the thread groove a by the same work rest 3 as shown in FIG. It may be ground. As a result, the outer diameter surface and the thread groove curved surface of the long work W can be accurately and concentrically finished. In this case, a grindstone for grinding the thread groove a is provided with a grindstone 25 for outer diameter grinding and its grindstone stand (not shown) in addition to the grindstone 2 for grinding the thread groove. It is preferable to continuously grind the outer diameter surface without removing the support by the end support members 1 and 1 at both ends of the long work W and the support by the work rest 3.

[0017]

EFFECT OF THE INVENTION A support device for thread groove grinding of a long work according to the present invention includes a pair of end support members for supporting the centers of both ends of a long work having a thread groove on the outer periphery, and the end support members. Since a grindstone for grinding the thread groove of the supported long workpiece and a work rest that supports the curved surface of the thread groove are provided in opposition to each other, regardless of the rigidity of the long workpiece, the shape of the outer diameter surface of the workpiece, It is possible to finish the thread groove of a long work piece to an equal diameter with good cylindricity without being affected by the dimensions. In the screw groove grinding support device, the work rest includes a ball-shaped member that comes into contact with a thread groove curved surface of the work, and a ball support member that movably supports the ball-shaped member in a predetermined range in the axial direction of the work. If equipped, even if there are differences in the thread groove leads depending on the workpiece, the ball-shaped member will be automatically centered so that it will always come into contact with the proper position on the curved surface of the thread groove without causing problems of misalignment. The thread groove grinding is performed accurately. Further, when a lower surface support member that supports two points on the outer diameter surface of the long work from below is provided, the long work can be placed and supported in the vicinity of the work rest at the time of setup change and the like. It is possible to easily adjust the advancing position of the member. The method for supporting the long workpiece in the groove groove grinding method of the present invention is such that several rounds of the highly rigid end portion of the long workpiece at the start of grinding support and grind the long workpiece only at both ends. Grinding is continued while supporting the ground surface of the thread groove that has already been ground with the work rest facing the grindstone, so high-precision groove grinding can be performed over the entire length of a long work without being affected by the shape or dimensional accuracy of the outer diameter of the work. Further, in the case where the ball-shaped member movably supported in the axial direction of the workpiece is used for grinding while supporting the curved surface of the thread groove, when performing groove grinding of various leads,
It is possible to perform accurate grinding without causing a problem of misalignment. In these thread groove supporting methods, after grinding the remaining portion of the thread groove curved surface, the outer diameter surface of the long work may be ground concentrically with the thread groove while supporting the thread groove curved surface with the work rest. . Thereby, the outer diameter surface and the thread groove curved surface of the long work can be accurately and concentrically finished.

[Brief description of drawings]

FIG. 1A is a plan view of a main part of a support device for thread groove grinding of a long work according to an embodiment of the present invention, and FIG. 1B is a side view of the same.

FIG. 2 is a plan view showing another portion of the device.

FIG. 3A is a vertical cross-sectional view of the workrest tip of the same apparatus, and FIG. 3B is a plan view of the workrest tip.

FIG. 4 is a plan view showing a machined outer diameter surface of the apparatus.

5A is a longitudinal sectional view of a main part of a conventional example, and FIG. 5B is a plan view of the conventional example.

[Explanation of symbols]

1 ... End support member, 2 ... Whetstone, 3 ... Workrest, 7 ...
Lower surface support member, 10 ... Ball-shaped member, 11 ... Ball support member, 11a ... Support groove, W ... Long work, a ... Screw groove

Claims (6)

[Claims] 1. A pair of end support members for supporting the centers of both ends of a long work having a thread groove on the outer circumference, and a grindstone for grinding the thread groove of the long work supported by the end support members. And a work rest for supporting the curved surface of the thread groove, and a supporting device for grinding the thread groove of a long work. 2. The work rest includes a ball-shaped member that comes into contact with a curved surface of a thread groove of the work, and a ball support member that movably supports the ball-shaped member in a predetermined range in the axial direction of the work. The support device for thread groove grinding of a long work piece according to claim 1. 3. The pair of end support members support a long work substantially horizontally, and the grindstone and the workrest are arranged so as to face each other substantially horizontally, and the pair of end support members are long in the vicinity of the grindstone. The support device for thread groove grinding of a long work according to claim 1 or 2, further comprising a lower surface support member that supports an outer diameter surface of the long work from below. 4. A process of supporting a center of both ends of a long work having a thread groove on its outer periphery to grind a thread groove curved surface for several circumferences from the end of the work without a work rest, and a remaining portion of the thread groove curved surface. A method for supporting a long work in grinding a thread groove, including a step of grinding the part while supporting a ground part of the thread groove curved surface with a work rest facing the grindstone. 5. The method for supporting a long workpiece in thread groove grinding according to claim 4, wherein the work rest is supported by a ball-shaped member movably supported in the axial direction of the work. 6. After grinding the remaining portion of the thread groove curved surface,
The method for supporting a long workpiece during grinding according to claim 4 or 5, wherein the outer diameter surface of the long workpiece is ground concentrically with the thread groove while supporting the thread groove curved surface with the work rest.