JP3365439B2 - Grinding equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding device for cylindrically grinding a work.

[0002]

2. Description of the Related Art Among the above-mentioned grinding machines, there is one in which a grindstone is moved forward on one end side of a work, and then the work is moved in the direction of the rotation axis to perform traverse grinding and the work is cylindrically ground in one pass. . In this type of grinding device, a taper portion is provided on the leading side in the traverse direction of the grindstone in order to roughly grind a workpiece during traverse grinding, and a straight portion for improving the surface roughness of the rough ground surface is provided on the trailing side. A whetstone is used.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In a grinding machine using a grindstone having a taper portion and a straight portion described above,
Since rough grinding and finish grinding can be performed in one pass, there is an advantage that the grinding efficiency can be improved and the surface roughness can be improved. However, if the grinding efficiency is increased at the time of traverse grinding, the amount of grinding in the straight portion of the grindstone increases, which causes problems such as grinding burn on the work, decrease in hardness, and increase in tensile residual stress.

The reason will be described below with reference to FIG. FIG. 7 shows a state in which the workpiece W is traversed by the cutting amount t with the grindstone G having the tapered portion G1 and the straight portion G2. When the workpiece W makes one revolution from this state, the grindstone G is indicated by a two-dot chain line. The position changes from the position shown by the solid line. The amount of movement in the work axis direction per one rotation of the work in this case is indicated by L. Then, since the shaded portion H in FIG. 7 must be ground by the straight portion G2 of the grindstone G having a poor sharpness for producing the surface roughness, the radial dimension r1 of the shaded portion H, that is, the volume becomes large. The amount of heat generated increases, and as described above, the grinding burn and the decrease in hardness are likely to occur.

Since the amount of heat generated increases as the volume of the shaded portion increases, the taper portion G1 of the grindstone G becomes larger.
The larger the taper angle θ is, or the larger the movement amount L in the work axis direction per one rotation of the work is, the larger it is. Therefore, the taper angle θ of the taper portion G1
However, in this case, since the width of the grindstone is limited in this case, as shown in FIG.
Therefore, it is necessary to grind the work, and in this case also, there is a problem that the grinding resistance becomes high and the heat generation amount becomes large.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. According to a first aspect of the present invention, the outer peripheral surface of a grindstone for grinding a work is parallel to the work rotation axis. A straight portion for finish grinding and a taper portion for rough grinding connected to this straight portion are formed. The taper angle on the side closer to the straight portion is smaller and the taper angle on the far side is larger. are as hereinbefore with two or more stages of taper and also to the claim 2, Wah
The outer peripheral surface of the grinding for grinding the click, constitute a straight portion for parallel finish grinding and the workpiece rotation axis, at curved surface portion and the tapered portion for rough grinding to be connected to the straight portion, the curved surface portion and the tapered portion Is a combination of a curved surface portion and a taper portion having a small tangent angle or taper angle on the side closer to the straight portion and a larger tangent line angle or taper angle on the far side.

[0007]

Function: While rotating the work and the grindstone respectively, the grindstone is relatively moved with respect to the work in the direction of the work rotation axis, rough grinding of the work is performed by the taper portion of the grindstone, and finish grinding of the work is performed by the straight portion. At this time, when the work makes one revolution, the portion ground by the taper portion one revolution before must be ground by the straight portion of the grindstone, but the amount that must be ground by the straight portion is the latter taper with a small taper angle. Due to the presence of the portion, the amount of heat generation can be extremely reduced, and the amount of heat generation can be reduced.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 denotes a bed of a grinding machine, on which a table 11 is guided and supported so as to be movable in the horizontal X-axis direction. A headstock 13 and a tailstock 14 are installed on the table 11 so as to face each other, and a work W rotates between the headstock 13 and the tailstock 14 around a rotation axis parallel to the moving direction of the table 11. It is supported so that it can be rotatably driven by the headstock 13. A grindstone 15 is guided and supported on the bed 10 so as to be movable back and forth in a horizontal Z-axis direction orthogonal to the moving direction of the table 11, and a thin grindstone 16 is parallel to the rotation axis of the workpiece W on the grindstone 10. It is rotatably supported around a large axis. The grindstone 16 is rotationally driven by a grindstone drive motor 17 via a belt transmission device (not shown).

The table 11 and the grindstone base 15 are moved by the servomotors 21 and 22 provided on the bed 10 to move the X-axis.
The feed is controlled in the axis and Z-axis directions,
The servomotors 21 and 22 are NC-controlled by the X-axis and Z-axis drive units incorporated in the NC device 23, respectively. Wheel head 15 of the headstock 13
The truing device 3 provided with a truing roll 30 for truing the grindstone 16 into a shape described later on the side surface on the side.
1 is attached.

As is well known, the grindstone 16 is a disk-shaped grindstone core provided with a grindstone layer on the outer periphery thereof. This grindstone layer is formed by combining CBN abrasive grains with a vitrified bond. Has been. As shown in FIG. 2, a straight portion 18 parallel to the workpiece rotation axis and a taper portion 19 having a two-step taper are formed on the outer peripheral surface of the grindstone 16. The taper portion 19 is the straight portion 1
8 of the gentle taper angle θ1 connected to the rear stage taper portion 19A, and the front stage taper portion 19 connected to the rear stage taper portion 19A and having a larger taper angle θ2 than the rear stage taper portion 19A.
It consists of B and. Rear and front taper parts 19A,
19B is used for rough grinding, and the straight portion 18 is used for finish grinding to obtain surface roughness. For this reason, the rear and front taper portions 19A and 19B are roughly trued by the truing device 31 so as to improve the sharpness, and the straight portion 18 is finely trued to provide surface roughness. 2 shows the taper angles of the rear-stage and front-stage taper portions 19A and 19B for the sake of easy understanding of the invention, in actuality, .theta.1 is about 1 to 2 degrees, .theta.2.
Is about 5 to 10 degrees.

Next, the operation cycle of the grinding device having the above-mentioned structure will be described with reference to FIG. When the grinding cycle is commanded, first, the table 11 is moved to the processing original position P1 corresponding to the grindstone 16 at the left end of the work W, and
The grindstone 16 and the work W are each rotationally driven. Subsequently, the grindstone base 15 advances the grindstone 16 to a position P2 where a predetermined amount of cut is applied to the work W, and in this state, the table 11 is traversed leftward by a predetermined amount, and the front taper portion 19B of the grindstone 16 is moved. And rear taper portion 19A
Rough grinding of the outer periphery of the work is performed, and then finish grinding of the outer periphery of the work is performed in the straight portion 18.

At this time, when the work W rotates once, the grindstone 16
4 changes from the position shown by the two-dot chain line to the position shown by the solid line as shown in FIG.
The portion ground by 9B must be ground by the straight portion 18 of the grindstone 16 having poor sharpness, but the amount of the shaded portion H (the radial direction r2) that must be ground by the straight portion 18 is the taper angle. Due to the presence of the small rear taper portion 19A, it becomes extremely small, and the amount of heat generation can be reduced.

In this way, the table 11 is traversed to the position P3 where the grindstone 16 passes the work W, and from that state, the grindstone base 15 is retracted to the position P4 to complete the one-pass grinding of the work W. Next, an operation cycle for truing the grindstone 16 into the above shape will be described with reference to FIG. When the truing cycle is commanded, the table 11 and the grindstone base 15 are feed-controlled, and the truing roll 30 is positioned with respect to the whetstone 16 at the truing start point P10 corresponding to the truing roll 30 at the right end of the whetstone 16. In this state, the grindstone base 15 is advanced, and the tip of the truing roll 30 is positioned at the position P11 corresponding to the extension of the front taper portion 19B of the grindstone 16. Subsequently, the two axes of the table 11 and the grindstone base 15 are simultaneously controlled to move the truing roll 30 along the taper angle θ2 of the front taper portion 19B of the grindstone 16 to the position P12.
The feed is controlled at a relatively high speed. As a result, the front taper portion 19B is roughly trued, and a rough ground surface is generated.

Then, the truing roll 30 is moved to the position P.
The tip of the truing roll 30 goes through the grinding wheel 1
Position P14 corresponding to the extension of the rear taper portion 19A of 6
To position. Then, the two axes of the table 11 and the grindstone base 15 are simultaneously controlled to feed the truing roll 30 along the taper angle θ1 of the rear taper portion 19A of the grindstone 16 to the position P15 at the same speed as described above. 19A rough truing.

Similarly, the truing roll 30 passes through the position P16, and the tip of the truing roll 30 corresponds to the extension of the straight portion 18 of the grindstone 16 at the position P1.
7, the table 11 is fed and controlled to feed the truing roll 30 along the straight portion 18 of the grindstone 16 to the position P18 at a slower speed than the above. As a result, the straight portion 18 is finely trued,
A finish ground surface is created to provide surface roughness.

In the above truing, in order to obtain the surface roughness of the straight portion 18, the straight portion 1
Although the truing speed of No. 8 is slower than the truing speed of the taper portion 19, both truing speeds may be the same. In the embodiment described above, the tapered portion 19
However, the taper portion 19 is not limited to a two-step taper, and may be a multi-step (three or more steps) taper.

Further, the taper portion 19 may not be a literal taper shape, but may be a curved surface portion 119 having a shape similar to a two-step or multi-step taper as shown in FIG. That is, the taper angle (tangential angle) is substantially reduced in the portion close to the straight portion 18,
Even if a curved surface is formed by a circular arc or a quadratic curve in which a taper angle (tangential angle) is substantially increased in a portion away from, the same effect as that of the above embodiment can be expected.

Further, instead of the taper portion 19, a combination of a taper shape and a curved surface shape can be used. In this case, the taper angle or the tangent angle is small on the side close to the straight portion 18, and the straight portion 18 is small. The side away from may be shaped so that the tangent angle or taper angle increases. Further, in the above-mentioned embodiment, the simple example in which the work W is cylindrically ground only by the table traverse by the thin grindstone 16 has been described, but the stepped work W can also be ground in one pass by the contouring control. Is.

Further, in the above-mentioned embodiment, the example in which the two-step taper portion is provided on one side of the straight portion has been described.
Two-stage tapered portions may be provided on both sides of the straight portion.

[0020]

As described above, according to the present invention, the outer peripheral surface of the grindstone for grinding the work is provided with the straight portion for finish grinding parallel to the rotation axis of the work and a plurality of steps for rough grinding connected to the straight portion. Since the taper or the combination of taper and curved surface is used , it is possible to reduce the amount that must be ground in the straight part of the grindstone. is there.

[Brief description of drawings]

FIG. 1 is an overall plan view of a grinding device according to the present invention.

FIG. 2 is a cross-sectional view showing the shape of a grindstone used in the present invention.

FIG. 3 is an operation diagram showing a grinding cycle.

FIG. 4 is a view showing a grinding state.

FIG. 5 is an operation diagram showing a truing cycle.

FIG. 6 is a sectional view showing the shape of a grindstone showing another embodiment of the present invention.

FIG. 7 is a view showing a grinding state by a conventional grindstone.

FIG. 8 is a diagram showing a reference diagram.

[Explanation of symbols]

16 whetstone 18 Straight part 19 Tapered part 19A Rear taper 19B front taper 119 curved surface 30 Truing Roll 31 Truing device W work

Continuation of the front page (56) Reference JP 58-59759 (JP, A) WILFREED KONIG and 2 others, High Speed Grinding of Any Conserving CBN Grinding, 5th INTERNATIONA LINGE RING RINGING, USA October, 2013, MR93-336-7 (58) Fields investigated (Int.Cl. ⁷ , DB name) B24B 5/04 B24D 5/00

Claims (2)

(57) [Claims] 1. A grinding machine for cylindrically grinding a work by rotating the work and the grindstone while moving the stone relative to the work in the direction of the work rotation axis, and the outer peripheral surface of the grindstone for grinding the work. Is composed of a straight portion for finish grinding parallel to the work rotation axis and a taper portion for rough grinding connected to this straight portion, and this taper portion has a small taper angle on the side close to the straight portion, A grinding machine characterized in that it has two or more steps of taper with a large taper angle on the far side. 2. An outer peripheral surface of a grindstone for grinding a work in a grinding device for cylindrically grinding the work by moving the grindstone relative to the work in the direction of the work rotation axis while rotating the work and the grindstone respectively. Is composed of a straight portion for finish grinding parallel to the work rotation axis, and a curved surface portion and a taper portion for rough grinding connected to the straight portion. The curved surface portion and the tapered portion are provided on the side close to the straight portion. The grinding machine is characterized in that the curved surface portion and the tapered portion are combined such that the tangent angle or the taper angle is small and the tangent angle or the taper angle on the far side is large.