JP2844872B2 - Forming method and forming apparatus for grinding wheel - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for forming a grinding wheel in which a grinding wheel surface of a grinding wheel used for ball screw groove grinding or the like is formed with a single-stone dresser.

(Prior Art) Conventionally, a ball screw shaft 70 as shown in FIGS.
As a method of forming a grinding wheel for forming the grinding wheel surface of the ball screw groove grinding wheel for grinding the flank surface 71 of the ball screw groove with a single stone dresser, for example, (1) As shown in FIG. Ball screw groove grinding wheel 90
Cam surface 92 that is similar to the gothic arch-shaped whetstone surface 91
And a stylus pressed against the cam surface 92
Using a single stone dresser 95 that moves integrally with the stylus 94, the right and left arc-shaped surfaces (R surfaces) 91 ₁ and 91 ₂ of the grindstone surface 91 are used.
The center of curvature O, in a state directed to the midpoint of O ₂ O _1, stylus
By moving the 94 following the cam surface 92, a single stone dresser 95 to pivot about the intermediate point O _2, whereby R surface 91 of a single stone dresser 95 the tip of the diamond _1, 91 ₂ a radius R
(2) As shown in FIG. 10, a right R surface 91 of the grinding wheel surface 91
₁ of the forming, carried out by pivoting said single-stone dresser 95 around its center O in a state where the single-stone dresser 95 for the center of curvature O of the right R surfaces 91 _1, left R surface of the grinding surface 91 91
_In the molding of ₂ , the turning center of the single-stone dresser is
Is offset from the center of curvature O ₁ of the left R surface 91 ₂ by a, and the single stone dresser 95 is centered around its center O ₁ with the single stone dresser 95 facing the center of curvature O ₁ of the left R surface 91 _2. A method of performing this by turning is known.

(Problems to be Solved by the Invention) However, the above-described conventional grinding wheel forming method (1)
In this case, it is difficult to manufacture the cam surface 92 with high precision, and when the cam surface 92 is worn, the right and left R surfaces 91 ₁ , 91 _{2 of the} grindstone surface 91 are removed.
Can not be formed with high accuracy, and single stone dresser 95
Since molding the R surface 91 ₁ of the left and right in a state of facing the intermediate point O _2, 91 _2, in the example of FIG. 9 per strongly left single stone dresser 95 when molding the right R side 91 _1, Left R surface 91 ₂
At an angle to the right will be hit stronger single stone dresser 95 each R surfaces 91 _1, 91 ₂ single stone dresser 95 when the molding, for example without striking a right angle, the left and right R surfaces 91 _1, 91 ₂ There was a problem that it could not be formed into a correct R shape.

Further, the at molding method of a conventional grinding wheel (2), a single stone dresser 95 left and right R surfaces 91 _1, 91 ₂ each center of curvature O, O
Since it is molded in a state facing ₁ , the single-stone dresser 95
Devoted perpendicular to the plane 91 _1, 91 _2, can be molded left and right R surfaces 91 _1, 91 ₂ to the correct R-shape. However, in the molding method (2), both ends beveled portion forming grinding surface of the grinding wheel surface 91, for example, when there is a plane of the R-plane 91 _1, 91 ₂ of the curvature radius smaller than the radius of curvature r, the surface The left and right R surfaces 91
_1, 91 ₂ can not be formed in the same processing step and, said R
The surfaces 91 ₁ and 91 ₂ and the chamfered portion forming grindstone surface must be formed in two steps, which is inefficient and increases the manufacturing cost. When the diamond is worn, the curvature of the grindstone to be formed changes, so that the position of the single stone dresser 95 with respect to the grindstone 90 must be manually adjusted, and this adjustment requires skill. Was.

The present invention has been made in view of such a conventional problem, and a grinding wheel capable of easily and precisely forming a grinding wheel surface with a single-stone dresser and reducing manufacturing costs. It is an object of the present invention to provide a molding method and a molding apparatus.

(Means for Solving the Problems) In order to achieve the above object, a method for forming a grinding wheel according to the present invention (claim 1) is directed to a method for grinding a ball screw groove grinding wheel having an arc-shaped thread groove forming wheel surface. A forming method for forming a whetstone surface with a single-stone dresser that rotates around its rotation center O by rotation of a rotation shaft, wherein the rotation center O of the rotation shaft is
Performs relative positioning between the rotating shaft and the grinding wheel so that the center of curvature of the thread groove forming wheel surface coincides with the center of curvature, and abuts the tip of the single stone dresser on the screw groove forming wheel surface at a certain angle. By rotating the rotating shaft while rotating the tip of the single stone dresser on a trajectory having a radius R around the rotation center O of the rotating shaft, the thread groove forming grindstone surface is rotated by the radius R of the radius. After forming the thread groove forming grindstone surface, the wear amount ΔR of the single stone dresser around the position of the rotation center O of the rotating shaft at the time of forming the screw groove forming grindstone surface is defined as a radius and Is calculated on an XY plane perpendicular to the rotation axis, and the rotation axis is rotated while the tip of the single stone dresser is brought into contact with the thread groove forming grindstone surface at a fixed angle to rotate the single stone dresser. Swivel the tip of Then, by displacing the rotation axis so that the rotation center O of the rotation axis moves on the calculated circular orbit according to the rotation of the rotation axis, the single stone with respect to the thread groove forming grindstone surface. The correction molding for the wear amount ΔR of the dresser is performed.

Further, in order to achieve the above object, a forming apparatus according to the present invention (claim 2) provides a grinding wheel surface of a ball screw groove grinding wheel having an arc-shaped thread groove forming grindstone surface by rotating a rotating shaft. A molding apparatus for molding with a single-stone dresser revolving around a rotation center O, wherein the rotating shaft is rotated by θ.
Direction driving means, X direction driving means for displacing the rotation axis in the X direction in an XY plane perpendicular to the rotation axis, and Y direction driving means for displacing the rotation axis in the Y direction in the XY plane, Control means for giving a numerical control command to each of the drive means in accordance with an input signal and a program, wherein the control means comprises: A command for causing the rotation center O to coincide with the center of curvature of the screw groove forming grindstone surface of the grinding stone is given to the X and Y direction driving means, and the tip of the single stone dresser is fixed to the screw groove forming grindstone surface. A command for rotating the rotating shaft so that the tip of the single stone dresser is turned on a trajectory having a radius R around the rotating center O of the rotating shaft in a state where the dressing device is in contact with the angle is the θ-direction driving means. The screw groove When performing the correction molding for the wear amount ΔR of the single stone dresser subsequent to the formation of the formed whetstone surface, the single stone dresser is centered on the rotation center O of the rotary shaft at the time of forming the thread groove forming whetstone surface of the whetstone. An arc trajectory having a wear amount ΔR as a radius is calculated on the XY plane, and the tip of the single stone dresser is turned while the tip of the single stone dresser is in contact with the thread groove forming grindstone surface. A command for rotating the rotating shaft is given to the θ-direction driving means, and the rotation center O of the rotating shaft moves on the calculated circular orbit in accordance with the rotation of the rotating shaft by the θ-direction driving means. A command for displacing the rotating shaft is given to the X and Y direction driving means.

(Operation) In the molding method and the molding apparatus according to the first and second aspects, the rotating shaft is rotated while the tip of the single stone dresser is brought into contact with the thread groove forming grindstone surface at a fixed angle, and the single stone dresser is formed. By turning the tip on a trajectory having a radius R around the rotation center O of the rotation shaft, the thread groove forming grindstone surface is formed into the surface of the radius R, and after forming the screw groove forming grindstone surface, The amount of wear Δ of the single-stone dresser around the position of the rotation center O of the rotating shaft when forming the thread groove forming grindstone surface
An arc trajectory with a radius of R is calculated on the XY plane perpendicular to the rotation axis, and the rotation axis is rotated while the tip of the single stone dresser is in contact with the thread groove forming grindstone surface at a certain angle to rotate the single stone dresser. By turning the tip and displacing the rotation axis so that the rotation center O of the rotation axis moves on the calculated arc trajectory in accordance with the rotation of the rotation axis, the single-stone dresser with respect to the thread groove forming grindstone surface. Of the wear amount ΔR, the surface of the thread groove forming grindstone always has a constant curvature, that is, a radius R.
Surface. Therefore, the grinding wheel surface of the grinding wheel for ball screw groove grinding can be easily and accurately formed by the single-stone dresser, and the manufacturing cost can be reduced.

(Example) Hereinafter, a method and an apparatus for forming a grinding wheel according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an apparatus for forming a grinding wheel according to one embodiment of the present invention.

This shaping device is a gothic arch (two arc surfaces having different centers) shaped screw groove forming grindstone surface 2 as shown in FIG.
Chamfered portion formed grinding wheel surface 3 ₁ of the concave arcuate at each end of the whetstone surface 2 and, 3 ₂ and the grinding surface 2 ₁ of the ball screw groove grinding grindstone 1 having, 3 _2, the rotary shaft 4 Is formed by a single-stone dresser 5 which turns around the rotation center O by the rotation of.
Gothic arch-shaped screw groove formed grindstone surface 2 is constituted by a left and right arc-shaped surface (R surface) 2 _1, 2 _2, respective R face 2 _1, 2 ₂ in terms of the curvature radius R, the curvature center is O, O ₁ (see FIG. 2). The arc-shaped chamfered part forming grindstone surfaces 3 ₁ and 3 ₂ are surfaces having a radius of curvature r, and the centers of curvature are O ₂ and O ₃ (see FIG. 2).

As shown in FIG. 1, this molding device has two upper and lower rotating shafts 4 rotatably supported by bearings 7 on a frame 6 of the device, and rotates integrally with the rotating shaft 4. A single stone dresser 5 is supported at the center of the bow-shaped arm 8. The single stone dresser 5 is supported by a dresser holder 9 attached to the center of the arm 8 so as to be adjustable in position with respect to the grindstone 1. Further, the molding apparatus includes a θ-direction driving unit 10 for rotating the rotating shaft 4 and an X-direction driving unit for displacing the rotating shaft 4 in the X direction in an XY plane (paper plane in FIG. 2) perpendicular to the rotating shaft 4. Means 11, a Y-direction drive means 12 for displacing the rotating shaft 4 in the Y direction perpendicular to the X direction in the XY plane, and respective drive means 10, 1 in accordance with various input signals and stored programs.
Control means 13 (see FIG. 4) for giving numerical control commands to 1 and 12 are provided.

The θ-direction drive means 10 has a servomotor supported by the frame 6 and driven by a command from the control means 13. The rotation of the servomotor is transmitted to the rotating shaft 4 via a pulley 14, a belt 15, and a pulley 16.

The X-direction driving means 11 is mounted on a support table 17 of the molding apparatus, and the movable table 11 supported by a linear guide device.
a, a servomotor driven by a command from the control means 13, and a feeding means for moving the movable base 11a in the X direction by rotation of the servomotor.

The Y-direction driving means 12 is mounted on a moving table 11a, and a moving table 12a supported by a linear guide device,
It has a servomotor driven by a command from the control means 13 and a feed means for moving the movable table 12a in the Y direction by rotation of the servomotor. The frame 6 is fixed on the moving table 12a, and the frame 6
It is supported movably in the X and Y directions on a support table 12a via Y direction driving means 11 and 12.

Each of the driving units 10, 11, and 12 is provided with a rotary encoder (not shown) that detects a rotation angle of each servo motor and feeds back the angle signal to the control unit 13.

Then, by using the above molding device, the second gothic arch shape of the screw, as shown in FIG grooved grinding surface 2 (left and right R surfaces 2 _1, 2 ₂₎ and arc-shaped chamfer portion in both ends forming grinding surface (r surface of the right and left) 3 _1, 3 ₂ and a method of molding a ball screw groove grinding grindstone 1 having described.

First, the radius of curvature R of the right R side 2 ₁ of the thread groove formed grindstone surface 2
Molded, together match the rotation center O of the rotating shaft 4 in the center of curvature O of the right side R surface 2 _1, at an angle the tip of the single-stone dresser 5 on the right R side 2 ₁ (e.g. perpendicular to the plane By rotating the rotating shaft 4 so that the same portion of the tip of the single-stone dresser always hits the tip of the single-stone dresser 5 to turn the tip of the single-stone dresser 5 on a track having a radius of curvature R at a constant speed V. Perform (Step 1). Thus, the right R side 2 ₁ is molded on the surface of a radius of curvature R in a section from point A to point B.

During this molding, while applying a constant angle with the tip of a single stone dresser 5 on the right R side 2 _1, since the tip of the single-stone dresser 5 to pivot the orbit radius of curvature R, of a single stone dresser 5 the tip of the diamond eliminating the shape error of the R-plane 2 ₁ by per, the R plane 2 ₁ is molded with high accuracy.

Following molding of the right R side 2 _1, the molding of the right r surface 3 ₁ to the plane of the curvature radius r, while rotating the rotary shaft 4 at a constant speed V, the rotation center of rotation O in the XY plane radius (R + r)
By moving from point O to point O 'on the circular arc (step 2). Thus, while per at an angle tip of the single-stone dresser 5 on the right side r surface 3 ₁ (e.g. perpendicular) to rotate a single stone dresser 5 by an angle theta ₁ shown in FIGS. 2 and 3, the As a result, the tip of the single stone dresser 5 is B
Move the section from the point to the point C with an arc of radius r.
Surface 3 ₁ is formed on the surface of the radius of curvature r. Even during the molding, while applying the tip of the single-stone dresser 5 at an angle to the right r surface 3 _1, since moving the tip of the single-stone dresser 5 in the radius of the arc r, the single-stone dresser 5 the tip of the diamond there is no right r surface 3 ₁ of the shape error due per, said right side r
Surface 3 ₁ is formed with high accuracy.

Following molding of the right r surface 3 _1, while maintaining the posture of the single stone dresser 5 at point C, (step of translating the rotational center O 'to the straight portion from point C to point D of the point C 3).

After the single-stone dresser 5 that has reached the point D is moved in the reverse direction to the above and returned to the point A, the section from the point A to the point D 'is defined as the section from the point A to the point D. It is moved similarly (step 4).

Thus, left R surface 2 ₂ and r-plane 3 ₂ is molded.

Then, the single-stone dresser 5 that has reached the point D 'is moved in the opposite direction to the above and returned to the point A (step 5). Thus, the forming of the grindstone 1 is completed.

Note that, in step 2 above, the left and right chamfered part forming grindstone surfaces are arc-shaped r-chamfered parts 70a as shown in FIG.
Instead, a straight c-chamfered portion 70b as shown in FIG.
In the case of this, while shaping the chamfered portion-forming grindstone surface, the rotation center O is applied to the grindstone surface in the XY plane while the tip of the single stone dresser 5 is applied to the grindstone surface at a fixed angle. This is performed by parallel movement.

The above steps 1 to 5 are executed by the control means 13 giving each of the driving means 10, 11 and 12 a command of numerical control according to various input signals and programs. Therefore, the speed of the single stone dresser with respect to the grinding wheel can be made variable.

The control means 13, during molding of the right R side 2 ₁ to the plane of the curvature radius R, based on an input signal, such as a radius of curvature R and the velocity V, to match the rotation center O to the center of curvature of the R surface 2 ₁ Command to the X and Y direction driving means 11 and 12 to rotate the rotating shaft 4 to turn the tip of the single stone dresser 5 on the orbit having the radius of curvature R.
A command is given to 10 (see FIG. 4), whereby step 1 is executed.

Then, the control unit 13, during molding of the right r surface 3 ₁ performed following the forming of the right R side 2 _1, based on the curvature radius R, the input signal such as r and velocity V, to rotate the rotary shaft 4 theta While giving a command to the direction driving means 10, X and Y move the rotation center O on an arc of a rotation radius (R + r) in the XY plane.
Command is given to the direction driving means 11 and 12 (see FIG. 4),
Thus, step 2 is performed.

Next, a method of correcting when the single stone dresser 5 is worn, that is, when the diamond is worn will be described with reference to FIGS. 5 and 6. FIG.

The ball screw grinding wheel 1 shown in FIG. 5 will be described as having an arc-shaped screw groove forming grindstone surface instead of the gothic arch-shaped screw groove forming grindstone surface 2 shown in FIG. The arc-shaped molding surface 2 ″ shown by the two-dot chain line in FIG.
The radius of curvature of the molding surface 2 ″ is larger than the regular dimension R by the wear amount ΔR of the single stone dresser 5 in the same manner as in Step 1 described above.

At the time of forming the forming surface 2 ″, the rotation center O is moved in the XY plane along an arc having a radius of the wear amount ΔR toward O ′ with the rotation of the rotary shaft 4.
The trajectory of the tip of the single stone dresser 5 is A on an arc with a radius of curvature R.
From point B to point B. As a result, the grinding wheel surface has a wear amount ΔR
Only the corrected surface is formed. Incidentally, such a correction method, it is possible to R surface 2 ₁ of the right and left shown in FIG. 2, 2 ₂ and the left and right r surface 3 _1, 3 ₂ is corrected only wear amount Δr single stone dresser 5.

The above correction method is executed by the control means 13 giving the drive means 10, 11 and 12 numerical control commands according to various input signals and programs. That is, the control means calculates the radius of curvature R, the velocity V, and the amount of wear Δ
On the basis of an input signal R or the like, while giving an instruction to the rotating shaft 4 in the theta direction drive unit 10 to rotate by an angle theta _2, to move the radius of the arc above the wear amount ΔR the rotation center O in the XY plane Giving commands to the X and Y direction driving means 11 and 12,
Thereby, the wear amount ΔR of the single stone dresser is automatically corrected.

The detection of the wear amount ΔR can be obtained by measuring the surface of the already formed grindstone or automatically measuring the tip position of the single stone dresser 5 by using a displacement meter, a touch sensor, or the like.

(Effects of the Invention) As described in detail above, in the forming method and the forming apparatus according to the first and second aspects, the rotating shaft is formed while the tip of the single stone dresser is brought into contact with the thread groove forming grindstone surface at a fixed angle. By rotating the tip of the single-stone dresser on a trajectory having a radius R around the rotation center O of the rotating shaft, the thread groove forming grindstone surface is formed into the surface of the radius R, and the screw groove is formed. After the formation of the formed grindstone surface, an arc trajectory having a radius of the wear amount ΔR of the single stone dresser around the position of the rotation center O of the rotation shaft at the time of forming the thread groove formed grindstone surface is perpendicular to the rotation axis.
Calculate on the XY plane, rotate the rotating shaft while abutting the tip of the single stone dresser on the thread groove forming whetstone surface at a certain angle, rotate the tip of the single stone dresser, and match the rotation of the rotating shaft Since the rotating shaft is displaced so that the rotation center O of the rotating shaft moves on the calculated circular orbit, the correction molding for the wear amount ΔR of the single stone dresser is performed on the thread groove forming grindstone surface. The groove forming grindstone surface can always be formed into a surface having a constant curvature, that is, a radius R. Therefore, the grinding wheel surface of the grinding wheel for ball screw groove grinding can be easily and accurately formed by the single-stone dresser, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a grinding wheel forming apparatus according to one embodiment of the present invention, FIG. 2 is an explanatory view showing a grinding wheel forming method according to one embodiment of the present invention, and FIG. FIG. 4 is an explanatory view showing a state in which the center of rotation of a rotating shaft is moved in an XY plane during forming of a grinding wheel forming a grinding portion, FIG. 4 is an explanatory view for explaining an operation of a forming apparatus according to one embodiment, FIG. FIG. 3 is an explanatory view showing a method of correcting the wear amount of a single-stone dresser in a method of forming a grinding wheel according to one embodiment of the present invention. FIG. FIGS. 7 and 8 are cross-sectional views each showing a ball screw, FIG. 9 is an explanatory view showing a conventional example of a method of forming a grinding wheel, and FIG. It is an explanatory view showing a conventional example. 1 ... Wheel for ball screw groove grinding, 2,2 '... Whetstone surface with thread groove, 3 ₁ , 3 ₂ ... Whetstone surface with chamfered part, 4 ... Rotary shaft, 5 ... Single stone dresser, 10 .... theta. Direction drive means, 11 ...
... X-direction driving means, 12... Y-direction driving means, 13.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B24B 53/00 B24B 47/25

Claims (2)

(57) [Claims] 1. A forming method for forming a grinding wheel surface of a ball screw groove grinding wheel having an arc-shaped thread groove forming grinding wheel surface with a single-stone dresser rotating around a rotation center O by rotation of a rotating shaft. Relative positioning between the rotating shaft and the grinding wheel so that the rotation center O of the rotating shaft coincides with the center of curvature of the thread groove forming grindstone surface, and the tip of the single stone dresser is formed into the thread groove forming surface. By rotating the rotating shaft while abutting the grindstone surface at a fixed angle, and rotating the tip of the single stone dresser on a trajectory having a radius R centered on the rotation center O of the rotating shaft, the screw groove is formed. After forming the formed grindstone surface to the surface of the radius R, and after forming the thread groove formed grindstone surface, the unit is formed around the position of the rotation center O of the rotating shaft at the time of forming the screw groove formed grindstone surface. Wear amount of stone dresser ΔR An arc trajectory having a radius is calculated on an XY plane perpendicular to the rotation axis, and the rotation axis is rotated while the tip of the single-stone dresser is brought into contact with the thread groove forming grindstone surface at a fixed angle to rotate the rotation axis. By turning the tip of the stone dresser and displacing the rotation axis so that the rotation center O of the rotation axis moves on the calculated circular orbit in accordance with the rotation of the rotation axis, the thread groove forming grindstone is formed. A method for forming a grinding wheel, wherein the surface is subjected to correction forming for the wear amount ΔR of the single stone dresser. 2. A molding apparatus for molding a grinding wheel surface of a ball screw groove grinding wheel having an arc-shaped thread groove forming grinding surface with a single-stone dresser which rotates around its rotation center O by rotation of a rotating shaft. A driving means for rotating the rotation axis, an X-direction driving means for displacing the rotation axis in an X-direction in an XY plane perpendicular to the rotation axis, and a Y-direction driving means for displacing the rotation axis in the XY plane. Y-direction driving means for displacing the driving means, and a control means for giving a numerical control command to each of the driving means according to an input signal and a program, the control means, the screw groove forming grindstone surface to the surface of radius R At the time of molding, a command to match the rotation center O of the rotating shaft with the center of curvature of the thread groove forming grindstone surface of the grindstone is given to the X and Y direction driving means, and the tip of the single stone dresser is One for the groove forming whetstone surface Command to rotate the rotating shaft so that the tip of the single-stone dresser is turned on a trajectory having a radius R about the rotating center O of the rotating shaft in a state where the dresser is in contact with the angle θ. When the correction molding for the wear amount ΔR of the single stone dresser is performed subsequent to the formation of the thread groove forming grindstone surface, the rotation center O of the rotary shaft at the time of forming the screw groove forming grindstone surface of the grinding stone is provided. An arc trajectory having a radius of the wear amount ΔR of the single stone dresser as a center is calculated on the XY plane, and the tip of the single stone dresser is in contact with the thread groove forming grindstone surface, and the single stone dresser is A command for rotating the rotating shaft so as to rotate the tip is given to the θ-direction driving unit, and the rotation center O of the rotating shaft is calculated according to the rotation of the rotating shaft by the θ-direction driving unit. In orbit Molding apparatus of the grinding wheel, characterized in that gives a command for displacing the rotary shaft so as to moving the X and Y-direction drive means.