JP2002059345A - Work grinding method in centerless grinding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the high grinding accuracy of a work W. SOLUTION: When the work W is fed in the rotational direction of a grinding wheel 11 via a carrier 13 and ground, the grinding of the work W is completed at the center height angle δ>0 deg.. Since the work W is not ground at the center height angle δ=0 deg., the circularity can be improved while suppressing the harmful effect of the distorted regular circle of odd-numbered angle to a minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of grinding a work in a centerless grinding machine capable of improving the roundness of the work and achieving a high degree of grinding accuracy.

[0002]

2. Description of the Related Art As a grinding method using a centerless grinding machine, a work is fed in the direction of rotation of a grinding wheel via a carrier rotating around an adjusting wheel, and the workpiece is ground between the grinding wheel and the adjusting wheel. Tangent feed grinding methods are known.

In the tangential feed grinding method, a work is put into a carrier above a grinding wheel and an adjusting wheel, and the workpiece is ground through the carrier to pass through a position at a center angle of 0 ° to be below the grinding wheel and the adjusting wheel. Therefore, a large amount of work can be efficiently ground by setting the input position and the discharge position of the work differently. However, the center angle refers to the total angle of the apex angle on the grinding wheel side and the apex angle on the adjustment wheel side of the triangle connecting the axes of the grinding wheel, the adjusting wheel, and the workpiece during grinding. Is a state in which the respective axes of the grinding wheel, the adjusting wheel, and the work are aligned on the same straight line.

[0004]

According to the prior art, since the outer periphery of the work is ground even at the position of the center angle of 0 °, the work has a shape of an odd-numbered equidistant circle such as a triangle or a pentagon. There is a problem that it is difficult to achieve sufficient roundness easily.

In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a centerless grinding machine capable of further improving the grinding accuracy of a work by terminating the work at an elevation angle δ> 0 °. The object of the present invention is to provide a method of grinding a workpiece in the above.

[0006]

According to the structure of the present invention for achieving the above object, when a workpiece is fed through a carrier in the rotational direction of a grinding wheel and ground, a center angle δ>
The gist of the invention is to end the grinding of the workpiece at 0 °.

[0007] The rough grinding of the work can be finished at the center angle δ ≒ 7 °, and the finish grinding can be finished at the center angle δ = 2 to 3 °.

Further, the work can be set at a center height for rough grinding and brought into contact with the grinding wheel, and can be set at a center height for finish grinding and brought into contact with the grinding wheel again.

Further, a plurality of works may be ground at the same time.

[0010]

According to the structure of the present invention, since the workpiece finishes grinding at the center elevation angle δ> 0 ° and does not grind at the center elevation angle δ = 0 ° at all, the influence of harmful odd-numbered equal-diameter distortion circles is reduced. It is difficult to remain, and extremely high roundness can be achieved. It should be noted that the workpiece after grinding is passed through the carrier at the center angle δ = 0 ° via the carrier without contacting the grinding wheel, and is discharged from the carrier at an appropriate discharge position.

[0011] By finishing rough grinding at the center height angle δ ≒ 7 ° and finishing finishing at the center height angle δ = 2 to 3 °, the workpiece can achieve sufficient roundness efficiently and at the same time. Variation in finish diameter can be minimized. If the center angle δ is increased, the roundness is improved.On the other hand, there is a manufacturing error in the arrangement pitch angle of the carrier pockets for storing and sending the work, and when the work in each pocket is positioned at the predetermined center angle δ. This is because the variation in the finished diameter of the work based on the positioning error or the like tends to occur remarkably. Further, by rough-grinding and finish-grinding the work at different center height angles δ of different sizes, it is possible to avoid the growth of a specific distortion component that deteriorates the roundness of the work.

The work is set at the center height for rough grinding and the center height for finish grinding and is brought into contact with the grinding wheel, so that there is no risk of inadvertent grinding at an inappropriate center height position. However, the work is to be once separated from the grinding wheel after the completion of the rough grinding.

If a plurality of workpieces are ground at the same time, the grinding efficiency can be improved several times.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

A method of grinding a work in a centerless grinding machine is carried out in a centerless grinding machine having a grinding wheel 11, an adjusting wheel 12, and a carrier 13 (FIGS. 1 and 2).

The grinding wheel 11 and the adjusting wheel 12 include a carrier 13
The adjustment wheel 12 is housed eccentrically toward the grinding wheel 11 with respect to the carrier 13. Note that the grinding wheel 11
Is formed in accordance with the shape of the work W that has been ground. The adjusting wheel 12 and the carrier 13 are connected to a common slide base 14 via shafts 12a and 13a, respectively.
It is singly supported by the upper bearings 12b and 13b. The slide base 14 is mounted on the gantry 15 via guide rails 15a, 15a so as to be able to move back and forth, and is connected to a screw shaft 16 parallel to the guide rails 15a, 15a via a screw member 16a. The screw shaft 16 is housed in a recess 15 b of the gantry 15 and is connected to a drive motor 16 b mounted on the rear of the gantry 15.

The carrier 13 is formed in a short cylindrical shape that closes the shaft 13a, and has a pocket 1 for accommodating the work W at every pitch angle θ = 30 ° with respect to the axis C3.
.. Are formed on the outer periphery. Note that each pocket 13c is sufficiently longer than the work W and is adapted to the diameter of the work W, and is opened on both the outer periphery and the inner periphery of the carrier 13.

Therefore, the centerless grinding machine rotates the grinding wheel 11 and the adjusting wheel 12 (in the directions indicated by arrows K1 and K2 in FIG. 1) and rotates the carrier 13 intermittently at every pitch angle θ (arrow in FIG. 1). K3 direction), between the grinding wheel 11 and the adjusting wheel 12, the work W in the pockets 13c, 13c.
W... Are sequentially fed in the rotation direction of the grinding wheel 11 for grinding.
Can be discharged below the carrier 13. Each pocket 13c is formed obliquely in a direction opposite to the rotation direction of the carrier 13 so that the work W can be stably held between the grinding wheel 11 and the adjustment wheel 12. The slide base 14 is provided with the drive motor 1.
By rotating the screw shaft 16 in the forward and reverse directions via the wheel 6b, the screw shaft 16 is moved back and forth with respect to the grinding wheel 11 (in the directions indicated by arrows K4 in FIGS. 1 and 2), and the distance L between the grinding wheel 11 and the adjusting wheel 12 is reduced. Can be varied.

Each work W to be sent through the carrier 13
Has the following positional relationship with the grinding wheel 11 and the adjusting wheel 12 (FIG. 1). That is, the grinding wheel 11 and the adjusting wheel 12
If the distance from the reference line A connecting the axes C1 and C2 to the axis Cw of the workpiece W being ground is defined as the center height h, the center height angle δ is a triangular grinding wheel connecting the axes C1, C2 and Cw. 1
With respect to the apex angle α on one side and the apex angle β on the adjustment wheel 12, δ = α +
β. However, the height h of the workpiece W on the reference line A is
= 0 and the center elevation angle δ = 0 °.

The centerless grinding machine grinds the work W as follows.

That is, the slide base 14 is retracted to the retreat limit, the carrier 13 is intermittently rotated at every pitch angle θ, and the workpieces W, W are sequentially loaded into the pockets 13c, 13c... (Arrows in FIG. 3A). ), The workpieces W, W... Are fed in the rotational direction of the grinding wheel 11, the centerless grinding machine operates as shown in FIG. 4, for example. In FIG. 4, the time t is plotted on the horizontal axis, and the center height h of the workpiece W and the distance L between the grinding wheel 11 and the adjustment wheel 12 are plotted on the vertical axis.

When the work W is loaded into the uppermost pocket 13c of the carrier 13 (time t = to in FIG.
.. Are simply fed (t = to), the work 13 is rotated to feed the works W, W... In the rotation direction of the grinding wheel 11 (to <t ≦ t 1), and the work W closest to the reference line A is roughly moved. Set the center height for grinding h = h1 (t = t
1). On the other hand, a set time T1 from the start of rotation of the carrier 13
Then, the slide base 14 is quickly advanced through the drive motor 16b and the screw shaft 16 to reduce the distance L between the shafts,
The work W is brought into contact with the grinding wheel 11 by moving the adjusting wheel 12 and the carrier 13 from the retreat limit retract position P1 to the contact position P2 (t = t2> t1). The work W at this time is pushed out of the pocket 13c via the adjustment wheel 12, and comes into contact with the outer periphery of the grinding wheel 11 (FIG. 3).
(B)).

Then, the slide base 14 is further advanced at a predetermined rough grinding speed (t2 <t≤t2a), and the adjusting wheel 12 and the carrier 13 are positioned and held at the coarse grinding position P2a (t2a <t≤t3). The workpiece W can be roughly ground, for example, about 90% of the allowance over the rough grinding time Ta = t3 -t2. At the rough grinding position P2a, the workpiece W being ground has a center angle δ ≒ 7 °.

When the rough grinding time Ta elapses (t = t3
), The slide wheel 14 is retracted rapidly to adjust the vehicle 1
2. Withdraw the carrier 13 to the intermediate position P3,
Is separated from the grinding wheel 11. On the other hand, slide base 1
4, after a set time T2 from the start of retreat, the carrier 13 is slightly rotated to finish the work W with the center height h = h2 for finish grinding.
<H1 (t = t4), then the slide base 14 is advanced to move the adjusting wheel 12 and the carrier 13 to the contact position P4 (t4 <t ≦ t5), and the work W
To the grinding wheel 11 again.

Then, the slide base 14 is further advanced at a predetermined finishing grinding speed lower than the rough grinding speed (t5 <t≤t5a), and the adjusting wheel 12 and the carrier 13 are positioned and held at the finishing grinding position P4a (t5a <T ≦ t
6) The remaining portion of the work W can be finish ground over the finish grinding time Tb = t6−t5 (FIG. 3 (C)). At the finish grinding position P4a, the workpiece W being ground has a center angle δ = 2 to 3 °. When the finish grinding time Tb elapses (t = t6), the slide base 14 is rapidly retracted, and the adjusting wheel 12, the carrier 13
To the retreat position P1.

The carrier 13 is rotated after the set time T3 from the start of the retreat of the slide base 14 so that the ground work h =
0, while passing downward through the position of the center height angle δ = 0 °, and setting the next work W to the center height h = h1 for rough grinding (t = t7). Also, the slide base 14 is advanced after a set time T1 from the start of rotation of the carrier 13, and thereafter, the same operation is repeated to grind the workpieces W, W. The ground work W is discharged below the carrier 13 by turning the pocket 13c downward as the carrier 13 rotates (FIG. 3).
(D arrow direction).

[0027]

[Other Embodiments] A work W
Can be formed in multiple rows in the axial direction of the carrier 13 (FIG. 5A).
By putting the works W, W... Into the pockets 13c, 13c... Of each row, a plurality of works W corresponding to the number of rows of the pockets 13c, 13c.
W ... can be ground simultaneously. However, at this time, the grinding wheel 11 and the adjusting wheel 12 also have double row pockets 13.
c, 13c ... so that they can correspond to the workpieces W, W ...
It shall be formed long enough in each axial direction. The pocket 13c may be formed to be long in the axial direction of the carrier 13 so that a plurality of works W, W... In addition, pocket 13
The cross-sectional shape of c may be any shape as long as the workpiece W to be stored can be held from the upper charging position to the lower discharging position of the carrier 13, and may be formed in a simple plane instead of forming both side walls as curved surfaces. Good (FIG. (C)).

In the above description, the carrier 13 is replaced with the grinding wheel 1 instead of the cylindrical type in which the adjusting wheel 12 is stored.
1, the work W, W... May be conveyed linearly from top to bottom between the adjustment wheels 12. The outer circumference of the grinding wheel 11 is adjusted to the shape of the finished outer circumference of the workpiece W, and the axis C1 is set.
In addition to a plane parallel to the axis or a slope with respect to the axis C1, or a curved surface that is concave or convex in the radial direction.

[0029]

As described above, according to the present invention, by ending the grinding of the work at the center height angle δ> 0 °, the influence of the odd-angle equal-diameter distortion circle generated during the grinding of the work is minimized. Since it can be suppressed, there is an excellent effect that the roundness of the work can be improved and high grinding accuracy can be easily realized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a centerless grinding machine.

FIG. 2 is a view corresponding to an arrow X in FIG. 1;

FIG. 3 is an explanatory diagram of an operation.

FIG. 4 is an operation explanatory diagram.

FIG. 5 is an explanatory diagram of a main part configuration showing another embodiment.

[Explanation of symbols]

 W ... Work h ... Center height δ ... Center height angle 11 ... Whetstone wheel 12 ... Adjustment wheel 13 ... Carrier

Claims (4)

[Claims] 1. A method of grinding a workpiece in a centerless grinding machine, wherein the workpiece is terminated at a center elevation angle δ> 0 ° when the workpiece is fed in a rotating direction of a grinding wheel via a carrier. . 2. The centerless grinding machine according to claim 1, wherein the workpiece finishes rough grinding at a center angle δ ≒ 7 ° and finishes grinding at a center angle δ = 2 to 3 °. Workpiece grinding method. 3. The method according to claim 1, wherein the workpiece is set at a center height for rough grinding and is brought into contact with the grinding wheel, and is set at a center height for finish grinding and is brought into contact with the grinding wheel again. Item 2. A method for grinding a work in a centerless grinding machine according to Item 2. 4. A method for grinding a workpiece in a centerless grinding machine according to claim 1, wherein a plurality of workpieces are ground simultaneously.