JP3102547B2 - Double-head grinding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-head grinding method for simultaneously grinding both parallel end faces of a work.

[0002]

2. Description of the Related Art As shown in FIG.
3 to improve the flatness and parallelism of the two end faces 2,
Consider that surface grinding of No. 3 is performed. This work 1
Has a through hole 4 in the center and a pair of annular grooves 5 on one end surface 2 side.
Due to the presence of these concave grooves 5, a portion other than the concave groove 5 and the through hole 4 on the one end surface (hereinafter referred to as a front end surface) 2 is a portion to be ground. On the other hand, on the other end face (hereinafter referred to as the back end face) 3, the entire area excluding the through-hole 4 is the part to be ground, so that the area of the part to be ground on the front end face 2 is larger than the area of the part to be ground on the back end face 3. Is also getting smaller. Conventionally, when grinding both end surfaces 2 and 3 of the work 1, the back end surface 3 of the work 1 before grinding has been entirely formed in a flat shape like the finished product shape after grinding.

If the two end faces 2 and 3 of the work 1 are separately ground using, for example, a rotary grinder, the area of the portion to be ground of the both end faces 2 and 3 of the work 1 is reduced as described above. Even if they are different, no particular problem occurs. But,
To increase the efficiency of grinding, use a double-headed grinding machine,
When trying to grind both ends 2 and 3 of the work 1 at the same time,
The following problems arise because the areas of the portions to be ground on both end faces 2 and 3 of the work 1 are different. That is, the grinding is performed as shown by chain lines A and B from the state before grinding shown by the solid line in FIG. 5B, but since the grinding area of the front end face 2 is smaller than the grinding area of the back end face 3, the front end face is ground. The grinding allowance of No. 2 is larger than the grinding allowance of the back end face 3. Therefore, the back end surface 3 side may be insufficiently ground, and the ungrounded portion may remain as black scale. On the other hand, back end face 3
If a sufficiently large grinding allowance is to be secured on the side, grinding is performed more than necessary on the front end surface 2 side, and the grinding time is long, and the efficiency is reduced.

[0004]

As described above, in the conventional double-head grinding method, when the grinding areas of both end faces of the work are different, the grinding of the both end faces is performed with different grinding areas from the beginning to the end. However, there has been a problem that insufficient grinding occurs on an end face having a large grinding area, or unnecessary grinding is performed on an end face having a small grinding area, and a long grinding time is required.

[0005] The present invention is intended to solve such a problem, and it is possible to uniformly grind both end faces of a work without shortage, and a grinding allowance does not become unnecessarily large at any end face. A first object is to provide a double-headed grinding method capable of improving the efficiency of grinding. Further, it is a second object of the present invention to make it possible to perform grinding with high stability in this double-head grinding method. It is a third object of the present invention to reliably cope with a chip generated at a corner of a work.

[0006]

According to a first aspect of the present invention, in order to attain the first object, parallel both end faces of a work are ground simultaneously. In a double-sided grinding method in which the area of the grinding portion is different, before grinding, the final ground portion of the work has a convex portion having an area substantially equal to the ground portion of the other end surface on the larger end surface of the workpiece. A part is formed in advance.

[0007] With this configuration, the grinding area is almost equal on both end faces of the work until the entire convex portion is shaved, so that the grinding allowance on both end faces of the work is almost equal.
Thereafter, the area of the part to be ground on one end face of the work becomes large, and therefore, the grinding allowance on one end face side becomes smaller than the grinding allowance on the other end face side. Since the grinding allowances at both end faces are substantially equal, the grinding allowances at both end faces become more uniform as a whole. In addition, at the stage where the area of the part to be ground on one end surface has increased, the convex portion of this one end surface has already been ground, and then the remaining part will be ground,
Insufficient grinding of one end face is prevented.

According to a second aspect of the present invention, in the double-head grinding method according to the first aspect of the present invention, the convex portion is formed on an outer peripheral portion of the workpiece in order to achieve the second and third objects. Things.

With this configuration, one end face of the work is ground from its outer peripheral portion. In addition, if the corner of the outer periphery of one end face of the work is chipped before grinding, the chipping is eliminated by increasing the grinding allowance at the outer periphery of the one end face.

According to a third aspect of the present invention, in the double-headed grinding method according to the second aspect of the present invention, in order to also achieve the third object, the convex portion is formed also in a peripheral portion of a hole in the work. Things.

According to this configuration, if the corner of the hole on one end face of the work is chipped before grinding,
The chipping is eliminated by increasing the allowance for grinding at the periphery of the hole.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a double-head grinding method according to the present invention will be described below with reference to FIGS.
The workpiece 11 to be ground has a disk shape, and both end faces 12, 13 are planar and parallel to each other. Work 11
Has a through hole 14 as a hole in the center, and a pair of annular grooves 15 on the front end face (the other end face) 12 side.
have. The plan view of the front end face 12 is the same as FIG. Then, both end faces 12 and 13 of the work 11 are simultaneously ground to increase their flatness and parallelism. On the front end face 12, a portion excluding the concave groove 15 and the through hole 14 is a part to be ground. On the other hand, on the back end face (one end face) 13, the whole except for the through hole 14 finally becomes the portion to be ground. Therefore, the area of the part to be ground on the front end face 12 is smaller than the area of the final part to be ground on the back end face 13.

FIG. 1 shows the shape of a workpiece 11 before grinding. On the back end surface 13 of the workpiece 11 before grinding, convex portions 16 and 17 are formed on an outer peripheral portion which is a portion to be ground and an inner peripheral portion around the through hole 14, respectively. The sum of the areas of these convex portions 16 and 17 (more specifically, the projected area on a plane orthogonal to the axial direction of the work 11) is substantially equal to the area of the portion to be ground on the front end face 12. The height of the convex portions 16 and 17 is smaller than the total grinding allowance b + d on the back end surface 13 side of the work 11. The height of the entire work 11 before grinding is set in consideration of grinding allowances a, b, c, and d. The heights of the projections 16 and 17 and the grinding allowances a, b, c and d are exaggerated in the drawings.

The work 11 of this embodiment is a sintered material manufactured by powder metallurgy. That is, it is manufactured by compressing a raw material powder with a powder molding press to form a green compact, and heating the green compact in a sintering furnace to sinter. The projections 16 and 17 are formed during powder molding. According to the powder molding, the projections 16 and 17 are formed.
The setting of the position and area can be easily and easily performed.

FIG. 2 shows a finished product after grinding. In this finished product, the convex portions 16 and 17 are eliminated, and the work 11
The rear end surface 13 is entirely flat.

FIGS. 3 and 4 schematically show a double-headed grinding machine used in the present grinding method. This double-headed grinding machine has a lower grindstone 21 and a vertically movable upper grindstone 22 arranged substantially in parallel.
As shown by the arc-shaped arrows, the grinding wheels 21 and 22 rotate in the same direction or in opposite directions. On the rear side and the front side of the grindstones 21 and 22, there are provided tables 23 and 24 on which the work 11 entering between the grindstones 21 and 22 and the work 11 coming out from between the grindstones 21 and 22 are placed. Furthermore, the whetstones 21 and 22 are placed on these tables 23 and 24.
Feeder guide 25 that guides work 11 through the gap
Is provided.

At the time of grinding, the workpiece 11 is fed by a feeder (not shown) and passes between the two grindstones 21 and 22 in a state in which the workpieces 11 are arranged side by side as shown by thick arrows in FIGS. In the meantime, both end surfaces 12, 13 of the work 11 are simultaneously ground by the rotating grindstones 21, 22.

At this time, the convex portions 16 and 17 of the back end surface 13 of the workpiece 11
Until substantially the entire surface of the workpiece 11 is cut, the grinding areas are substantially equal on both end faces 12 and 13 of the workpiece 11 (first stage). The positions indicated by broken lines C and D in FIGS. 1 and 2 indicate the positions where the grinding proceeds by the end of the first stage. In this first stage, the grinding areas a and b of the end faces 12 and 13 of the work 11 are also substantially equal because the grinding areas of the end faces 12 and 13 are substantially equal. After the entire protrusions 16 and 17 have been cut, the grinding area of the back end face 13 of the work 11 increases (second stage). of course,
Since the flatness and parallelism of the workpiece 11 before grinding are not high-precision, the change in the grinding area is not constant, and the transition from the first stage to the second stage is not always clearly determined. . In the second stage, since the grinding area of the back end face 13 is larger than the grinding area of the front end face 12, the grinding allowance c on the front end face 12 side becomes larger than the grinding allowance d on the back end face 13 side.

As described above, in the second stage, the grinding allowance c on the front end face 12 side is larger than the grinding allowance d on the back end face 13 side. Teens a, b
Are substantially equal, the grinding allowances a + c and b + d of both end faces 12 and 13 become more uniform as a whole. For example, the first-stage grinding allowances a and b are 0.1 mm, the second-stage grinding allowance c on the front end face 12 side is 0.1 mm, and the second-stage grinding allowance d on the back end face 13 side is 0.06.
mm, the total grinding allowance a + c on the front end surface 12 is 0.2 m
m, the total grinding allowance b + d on the back end face 13 side is 0.16 mm, and the difference between the two is small. On the other hand, if the grinding area of the back end face 3 is large from the beginning as in the prior art, the grinding allowance e on the front end face 2 side is reduced.
If it is set to 0.2 mm, the grinding allowance f on the back end face 3 side will be as small as 0.12 mm, and conversely, the grinding allowance f on the back end face 3 side will be 0.2 mm.
Then, the grinding allowance e on the front end face 2 side is 0.33 mm, which is larger than necessary.

On the back end surface 3, the projections 16 and 17 are already ground by the second stage.
The rest will be ground. By such stepwise grinding, the grinding allowance b + d on the back end surface 13 side as described above.
In combination with the fact that it can be made large, it is possible to prevent insufficient grinding of the back end face 3.

The portion of the work 11 where the largest grinding allowance is required is a corner portion where chipping is likely to occur in a process before grinding. For example, on the back end face 13, they are the corners of the outer periphery and the corners of the through hole 14. On the other hand, on the back end surface 13 of the workpiece 11 before grinding, the convex portions 16 and 17 are formed on the outer peripheral portion and the inner peripheral portion around the through hole 14. Also, by increasing the grinding allowance b + d of the inner peripheral portion, even if the outer peripheral corner of the back end face 13 or the corner of the through hole 14 is chipped before the grinding, the chipping can be reliably eliminated.

Conversely, the convex portion 17 on the inner peripheral portion is necessary due to the presence of the through hole 14. If there is no hole portion such as the through hole 14, the convex portion is provided only on the outer peripheral portion. Just do it. Of course, it is necessary to make the area of this projection approximately equal to the grinding area of the opposite end face.

It is to be noted that a chamfer or the like may be formed at a corner portion of the work, and there may be a case where the problem is not serious as well as the chipping.

Further, since the convex portion 16 is provided on the outer peripheral portion of the end surface 13, the end surface 13 is ground from the outer peripheral portion. Thereby, grinding can be performed with high stability.

As described above, finally, the grinding area is reduced to the front end face.
Protrusions 16 and 17 having an area substantially equal to the grinding area of the front end face 12 are provided on the back end face 13 which is larger than 12 so that the end faces 12 and 13 of the work 11 can be uniformly and thoroughly ground. Therefore, the unground portion does not remain as black scale or the like, and the grinding allowance does not become unnecessarily large on any of the end surfaces 12 and 13. Thereby, the grinding time can be shortened, and the efficiency of the grinding process can be improved.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. For example,
The shape of the work is not limited to that of the above embodiment,
The present invention can be generally applied to a work having parallel flat end faces and different areas of the final ground portion of these end faces. Further, the work in the above-described embodiment is a sintered material manufactured by powder metallurgy, but the work is not limited to one manufactured by powder metallurgy, and may be a melted material or the like.

[0027]

According to the first aspect of the present invention, when simultaneously grinding both end faces of the work, the final areas to be ground on the both end faces are different from each other. In the part to be ground on the end face with the larger area of the part to be ground, a convex part having an area approximately equal to the part to be ground on the other end face is formed, so that both ends of the work can be ground uniformly and without shortage. In addition to this, the grinding allowance does not become unnecessarily large at any end face, the grinding time can be shortened, and the efficiency of the grinding process can be improved.

According to the second aspect of the present invention, in addition to the effect of the first aspect, since the convex portion is formed on the outer peripheral portion of the work, the grinding can be performed with high stability, and the one side of the work can be ground before grinding. This chipping can be surely erased even if a chipping occurs in the outer peripheral corner of the end face.

According to the third aspect of the present invention, in addition to the effect of the second aspect of the present invention, the convex portion is also formed in the periphery of the hole in the work, so that one side of the work before grinding is formed. Even when the corner of the hole on the end face is chipped, this chipping can be reliably eliminated.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a double-head grinding method according to the present invention, in which (a) is a cross-sectional view of a work before grinding, and (b) is a plan view of a back end surface of the work before grinding.

FIG. 2 is a cross-sectional view of the work after grinding.

FIG. 3 is a schematic side view of a double-headed grinding machine used in the same method.

FIG. 4 is a schematic plan view of a double-headed grinding machine used in the same method.

FIG. 5 shows an example of a conventional double-head grinding method.
(A) is a plan view of the front end face of the work, and (b) is a cross-sectional view of the work.

[Explanation of symbols]

 11 Workpiece 12 Front end face (the other end face) 13 Back end face (the end face with the larger area of the part to be ground) 14 Through hole (hole) 16 Convex part 17 Convex part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B24B 7/17

Claims (3)

(57) [Claims] 1. A double-sided grinding method for simultaneously grinding both parallel end faces of a work, wherein the area of a final ground portion on both end faces of the work is different. A double-head grinding method characterized in that a convex portion having an area substantially equal to that of the ground portion on the other end surface is formed on the ground portion on the end surface having the larger area of the portion. 2. The double-head grinding method according to claim 1, wherein the convex portion is formed on an outer peripheral portion of the work. 3. The double-head grinding method according to claim 2, wherein the convex portion is also formed around a hole in the work.