JP2901875B2 - Truing method of super abrasive grinding wheel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a truing method for forming (truing) an outer peripheral surface of a superabrasive grinding wheel into a convex curved surface other than a cylindrical surface.

[0002]

2. Description of the Related Art For example, as a method of truing the outer peripheral surface of a superabrasive grinding wheel, as shown in FIG. 5, a cup-shaped grindstone 2 provided on a table 1 is attached to a wheel shaft 3a of a grinding wheel 3. The outer peripheral surface of the grinding wheel 3 that is rotated by the cup-shaped grindstone 2 while being driven and rotated by a motor 4 about an orthogonal axis and reciprocatingly driven in a direction (tangential direction indicated by an arrow D) orthogonal to the wheel axis 3a. A method of truing is known.

The truing method employs a system in which the cup-shaped grindstone 2 is reciprocated in a direction (tangential direction) perpendicular to the wheel shaft 3a, that is, a vertical feed system, so that the cup-shaped grindstone 2 is parallel to the wheel shaft 3a. It is well known that a grinding wheel that excels in truing accuracy and that has a high cylindricity (roundness) can be obtained as compared with a system that reciprocates in the direction of movement, that is, a lateral feed system.

However, the above-mentioned conventional method is suitable for truing the outer peripheral surface of the grinding wheel 3 to a cylindrical surface, but it is impossible to truing the cross-sectional shape to an arc or other convex curved surface. For this reason, when truing to a convex curved surface other than the cylindrical surface, a rotary dresser or electric discharge machining has been used.

However, the rotary dresser is expensive and is not suitable for high-mix low-volume production, and requires dressing after truing, which is troublesome and difficult to form a highly accurate wheel. Was. On the other hand, electric discharge machining cannot be applied to anything other than metal bonding. For these reasons, there has been a demand for the development of a truing method capable of accurately truing the outer peripheral surface of a grinding wheel to a convex curved surface by a simple method.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to pay attention to the fact that the truing method of the longitudinal feed system is effective in obtaining a grinding wheel having a high cylindricity, and to take advantage of the advantage of the longitudinal feed system. And other elements to compensate for grinding wheel wear during truing.
It is another object of the present invention to provide a truing method capable of easily and accurately truing the outer peripheral surface of a grinding wheel to a desired convex curved surface.

[0007]

In order to solve the above-mentioned problems, a truing method according to the present invention comprises the steps of: providing an outer peripheral surface of a super-abrasive grain grinding wheel to be trued rotating around a first axis; A soft cup-shaped grindstone rotating about a second axis orthogonal to the moving direction in a feed direction that is a direction parallel to the direction of the second axis, and abuts the cup-shaped grindstone. The super-abrasive grains after being formed are reciprocated with respect to the super-abrasive grinding wheel in a tangential direction perpendicular to the first axis and the second axis and in contact with the outer peripheral surface of the super-abrasive grinding wheel. located in the center of curvature of the grinding wheel outer peripheral surface, is swung about the swing axis of the tangential direction parallel to the direction, own the outer peripheral surface of the superabrasive grinding wheel around the pivot axis With given curvature
When forming into a convex curved surface, each time the cup-shaped grindstone moves one stroke in the reciprocating direction along the tangent line , by giving a predetermined amount of cut corresponding to the wear of the cup-shaped grindstone in the feed direction, The present invention is characterized in that the influence of the wear of the soft cup-shaped grinding wheel is absorbed, and the outer peripheral surface of the superabrasive grinding wheel is formed into a convex curved surface having a desired curvature around the swing axis . As the cup-shaped grindstone, green silicon carbide (GC), black silicon carbide (C), it is preferable to use one made of any of the abrasive grains alumina.

[0008]

1 shows an example of an apparatus used for carrying out the method of the present invention. In the figure, reference numeral 10 denotes a flat superabrasive grinding wheel (hereinafter referred to as a grinding wheel) to be trued.
U. ) And 11 indicate a truing device.

The truing apparatus 11 includes an X-axis table 1 capable of position control in a direction (X-axis direction) orthogonal to the axis (first axis) of a wheel shaft 10a of the grinding wheel 10.
2 and a Y-axis table 13 disposed on the X-axis table 12 and capable of position control in a direction (Y-axis direction) parallel to the wheel axis 10 a of the grinding wheel 10. Is a base 14 having a worm wheel 15
Is swingably supported by a swing shaft 17 having an axis (swing axis) 17a parallel to a tangent L passing through a contact point of the grinding wheel outer peripheral surface 10b with the grindstone 16, and swinging as a driving source. A motor 18 is fixed, and a worm 19 connected to the swing motor 18 meshes with the worm wheel 15.
5, the grinding wheel 1 by the worm 19 and the oscillating motor 18
Six swing means 20 are configured.

A bracket 23 is supported on the vertical portion 14a rising from one end of the base 14 so as to be vertically movable, and is moved vertically by a lifting motor 24 along the tangent line L, that is, the wheel of the grinding wheel 10 as shown in FIG. The bracket 23 is provided with a table guide 25 at an upper end thereof, and a feed table 26 is movable on the table guide 25 with respect to the grinding wheel 10. The table guide 25, the feed table 26, and the feed motor 27 form a cut feed means 28 for giving a cut feed to the grindstone 16 by the feed motor 27. I have.

On the support frame 30 provided on the feed table 26, the cup-shaped grindstone 16 is supported so as to be rotatable about an axis (second axis) 16a orthogonal to the tangent L. In addition, a grindstone motor 31 as a drive source of the grindstone 16 is attached.

In order to truing the outer peripheral surface 10b of the grinding wheel 10 to a symmetrical circular arc surface using the truing device 11 having the above configuration, first, the X-axis table 1 is used.
2 and the position of the Y-axis table 13 are numerically controlled by a controller (not shown), and the axis 17a of the swing shaft 17 is placed at the center of the thickness of the grinding wheel 10 (see FIG. 2).

Next, the grinding wheel 10 and the grindstone 16 are rotated, and the base 14 is oscillated by the oscillating motor 18 via the worm 19 and the worm wheel 15 so that the axis (oscillating axis) 17a is centered. The whetstone 16 is swung left and right, and the bracket 2 is
3 is driven, and the whetstone 16, the first axis and the second
And is in contact with the outer peripheral surface of the superabrasive grinding wheel.
The whetstone 16 is pressed against the outer peripheral surface 10b of the grinding wheel 10 while moving up and down in the tangential direction to form the surface. At this time, the table 26 feed motor 27 feed each time the grinding wheel 16 makes one stroke movement in the tangential direction is advanced by a predetermined amount, performing truing by feeding a constant amount at a time the whetstone 16 against the grinding wheel 10 Then, the radius of curvature of the outer peripheral surface 10b of the grinding wheel 10 is gradually reduced, and finally the outer peripheral surface of the grinding wheel 10 is trued into an arc surface having a predetermined radius of curvature.

Here, the principle of the truing will be described in more detail. As shown in FIG.
The outer peripheral surface 10b of the grinding wheel 10 is to be formed into an arc surface by a linear envelope. That is, the work surface of the cup-shaped grindstone 16 indicated by a straight line in the drawing is brought into contact with the outer peripheral surface 10b of the grinding wheel 10, and the grindstone 16 is centered on a swing axis 17a placed at the center of curvature of a given arc surface. By swinging to the left and right, an arc surface having a constant curvature can be formed. However, if the whetstone 16 is worn while the whetstone 16 moves one stroke from the left side to the right side of the grinding wheel 10, as shown in FIG. Smaller and less uniform.

Therefore, to form a given arc surface A,
Generally, it is sufficient to use a truing tool with extremely high wear resistance or to correct the wear amount of the tween tool, but since a truing tool with high wear resistance basically uses a diamond tool, It is inevitable that the grinding performance of the wheel is deteriorated later, and the method of correcting the wear amount has a problem that the apparatus becomes complicated.

Therefore, the present invention uses a soft grindstone 16 , which is provided with the first axis and the second axis.
The abrasion of the grindstone 16 is achieved by giving a predetermined amount of feed for each stroke in the tangential direction and adjusting the depth of cut so as to be perpendicular to the line and in contact with the outer peripheral surface of the superabrasive grinding wheel. So that it absorbs. In this case, if the cut provided by using the soft grindstone 16 is completely removed, the advance of the grindstone surface in the cut feed direction (direction parallel to the rotation axis of the grindstone) during one stroke of the linear envelope is completely completed. It can be neglected and a given cross section can be formed. If the amount of wear is smaller than the amount of feed of the grindstone 16, the arc surface to be formed has a larger curvature than the given arc surface A as shown in FIG. 3C.

Thus, the grinding wheel 16 oscillating while reciprocating in the tangential direction is formed while giving a constant feed for each stroke in the tangential direction, and as shown in FIG. The radius is gradually reduced as shown by a chain line A ₁ A ₂ , and is finally formed into an arc surface A having a predetermined curvature shown by a solid line.

The grinding stone 16 has a green silicon carbide (G).
C), black silicon carbide (C), white alumina (WA)
It is desirable to use one made of alumina (Al ₂ O ₃ ) abrasive grains such as the above. When such a soft grindstone 16 is used, the grinding wheel 10 is formed by the lapping effect of the abrasive grains dropped from the grindstone 16. Has been slightly corrected, and it has been revealed that a dressing effect can be obtained simultaneously with truing.

The above is a case where the outer peripheral surface of the grinding wheel 10 is trued to an arc surface symmetrical to the left and right. However, when other convex curved surfaces are used, the X-axis table 12 and the Y-axis table 13 are numerically controlled. Swing axis 17a
May be changed, and the straight line envelope may be performed by the method described above.

Experimental Example 1 Using the truing apparatus shown in FIG. 1, the outer peripheral surface of a metal bond diamond wheel having a particle size of 270/325, a concentration of 100, a wheel diameter of 205 mm, and a width of 10 mm was subjected to a wheel rotation speed of 800 rpm.
m. to truing on the arc surface.

The truing conditions at this time are as follows:
mm GC140H cup type grindstone, grindstone rotation speed 1500 rpm, grindstone feed amount 0.01 mm / stroke, vertical feed stroke 15 mm, vertical feed speed 120
Rotation / min, swing angle 60 degrees, swing speed is 20 sec / stroke during coarse truing, 1 during finish truing.
0 sec / stroke.

The reason why the rocking speed of the grindstone 16 is increased during the finishing truing is to increase the forming accuracy by minimizing the accumulated uncut amount of the grindstone 16 during one stroke. The radius of curvature of the arc surface of the final grinding wheel was set to 8 mm. Approximately 20 minutes after the start of truing, truing was terminated when the entire outer peripheral surface of the grinding wheel 10 hit, but truing could be performed with a precision within 20 μm on a given arc surface.

Experimental Example 2 Using the truing apparatus shown in FIG. 1, the outer peripheral surface of a resin bonded diamond wheel having a particle size of 270/325, a degree of concentration of 150, a wheel diameter of 350 mm and a width of 10 mm was subjected to a wheel rotation speed of 800 rpm.
m. to truing on the arc surface.

The truing conditions at this time are as follows:
mm GC280H cup-type grindstone, the grindstone rotation speed is 1500 rpm, and the grindstone feed amount is 0.001 mm /
Stroke, vertical feed stroke 15mm, vertical feed speed 17
Times / min, and the swing angle was 160 degrees. The radius of curvature of the arc surface of the final grinding wheel was set to 8 mm. Approximately 20 minutes after the start of truing, truing was terminated when the entire outer peripheral surface of the grinding wheel 10 hit.
Truing could be performed with a precision within ± 1 μm for a given arc surface.

[0025]

As described above, according to the present invention, the cup-shaped grindstone brought into contact with the outer peripheral surface of the grinding wheel is reciprocated in the tangential direction with respect to the grinding wheel and oscillated. By adjusting the depth of cut by providing a required amount of feed for each stroke, the outer peripheral surface of the grinding wheel can be easily and accurately trued to a desired convex curved surface.

[Brief description of the drawings]

FIG. 1 is a side view illustrating a truing method of the present invention together with an apparatus.

FIG. 2 is a diagram illustrating the principle of truing according to the present invention.

FIG. 3 is a diagram illustrating the principle of truing according to the present invention.

FIG. 4 is a diagram illustrating the principle of truing according to the present invention.

FIG. 5 is a perspective view illustrating a conventional truing method together with an apparatus.

[Explanation of symbols]

Reference Signs List 10 grinding wheel 10a wheel shaft 10b outer peripheral surface 16 cup-shaped grindstone 16a grindstone axis 17a swing axis L tangent

Continuation of the front page (56) References JP-A-4-82667 (JP, A) JP-A-55-42754 (JP, A) JP-A-61-205761 (JP, U) JP-A-48-43971 (JP, A) , Y1) (58) Field surveyed (Int. Cl. ⁶ , DB name) B24B 53/06 B24B 53/00

Claims (2)

(57) [Claims] A truing rotating about a first axis.
A soft cup-shaped grindstone (16) rotating around a second axis (16a) orthogonal to the first axis is attached to the outer peripheral surface of the target superabrasive grinding wheel (10) by the second axis.
The cup-shaped grinding wheel (16) is brought into contact by moving in a feed direction which is a direction parallel to the direction of (16a).
With respect to (10), while reciprocating in the direction of a tangent (L) orthogonal to the first axis and the second axis and in contact with the outer peripheral surface of the superabrasive grinding wheel (10) , Located at the center of curvature of the superabrasive grinding wheel outer peripheral surface,
The swing axis (17 ) in the direction parallel to the direction of the tangent (L)
is swung around the a), the superabrasive grinding wheel (1
0) around the swing axis (17a).
When forming into a convex curved surface having a curvature, the cup-shaped grindstone (16) reciprocates along the tangent (L).
Every time one stroke movement in the moving direction, by giving a predetermined amount of cut corresponding to the wear of the cup-shaped grindstone (16) in said feed direction, to absorb the impact of wear of the cup-shaped grinding wheel of the soft (16) The outer peripheral surface of the superabrasive grinding wheel (10) is pivoted along the axis of rotation.
Forming a convex curved surface having a desired curvature around (17a) . 2. The cup-shaped grinding wheel is made of green silicon carbide (G).
C), black silicon carbide (C), claim 1, characterized in that it is formed by either of the abrasive grains of alumina
3. The truing method of the superabrasive grinding wheel according to 1.).