JP2669664B2 - Parallel grinding method for cylindrical work surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is designed to bring a grindstone head closer to a rotating work piece, and to make a cylindrical work surface of a workpiece parallel by a grinding wheel that is supported by the grindstone head and rotates. It relates to a method of grinding.

(Prior Art) In this type of grinding method, depending on the material shape of the workpiece, etc., as shown in FIG.
There is a case where a gradually wears in a tapered shape and the work surface Wa is ground in a tapered shape instead of a cylindrical shape. In such a case, each time the taper generated on the work surface Wa approaches a predetermined allowable limit, the grinding surface 41a is shaped by the truing device 39 so as to have an original cylindrical shape, as shown in FIG. 5 (b). Then, as shown in FIG. 5 (c), the work surface to be ground
Wa has a cylindrical shape.

(Problems to be Solved by the Invention) However, in such a conventional technique, truing must be performed relatively frequently, and particularly in the case of a hard grinding wheel using CBN abrasive grains or diamond abrasive grains, one truing is required. The processing time is long, and the processing efficiency is reduced. Further, in the case of the hard grinding wheel as described above, it is extremely difficult to remove the taper by truing by using any truing device. SUMMARY OF THE INVENTION It is an object of the present invention to improve a machining efficiency by removing a taper of a work surface caused by uneven wear of a grinding surface of a grinding wheel in a tapered shape without performing truing.

(Means for Solving the Problems) For this purpose, the method for parallel grinding a cylindrical work surface according to the present invention is a grinding wheel that rotates as illustrated in FIGS.
The grindstone base 30 supporting 41 is brought relatively close to the rotating workpiece W so that the cylindrical work surface Wa of the workpiece W is fixed to the grinding wheel 41.
In the method of parallel grinding by means of the above method, the grindstone 30 can be swung by a desired angle around a swivel axis orthogonal to the rotation axis of the workpiece W, and angle display means 77 for displaying the swivel angle of the grindstone 30 is provided. The width L in the axial direction of the work surface Wa and the diameters D ₁ and D ₂ of both ends of the work W which has been trial-ground by the grinding surface 41 a of the grinding wheel 41 are measured, and the work surface Wa is measured based on the measured values. The taper half apex angle α is obtained, and the taper is reduced by the half apex angle α around the turning axis by this half apex angle α manually while watching the turning angle of the wheel head 30 displayed on the angle display means 77. After turning in the direction to
It is characterized in that the work surface Wa of the work W is ground by the grinding surface 41a.

(Operation) The work surface Wa of the work W, which has been trial ground by the grinding wheel 41, is measured by measuring the axial width L of the work surface Wa and the diameters D ₁ and D ₂ of both ends.
A direction for decreasing the taper around the turning axis of the wheel head 30 by this half vertical angle α manually while watching the turning angle of the wheel head 30 displayed on the angle display means 77 by obtaining the half angle α of the taper Turn to. As a result, the generatrix in contact with the work surface Wa on the grinding surface 41a of the grinding wheel 41 is parallel to the rotation axis of the work W with high accuracy equivalent to the detection accuracy of the half apex angle α of the taper. Therefore, in this state, if the grinding wheel 41 is rotated to bring the grinding wheel base 30 close to the rotating workpiece W, the workpiece surface Wa is ground into a cylindrical shape with high precision without taper.

(Effects of the Invention) As described above, according to the present invention, the taper of the work surface Wa caused by the tapered uneven wear of the grinding surface 41a of the grinding wheel 41 can be removed with high accuracy without performing truing. As a result, irregularities are generated on the generating line of the grinding surface, and the work surface Wa
It is not necessary to true the ground surface until the unevenness of is beyond the allowable limit, and the grinding efficiency of the cylindrical work surface Wa can be improved.

(Examples) The present invention will be described below with reference to Examples shown in FIGS. 1 to 4.

First, referring to FIG. 2, the overall structure of the cylindrical grinder used for carrying out the present invention will be described. Table on bed 10
A spindle headstock 12 bearing a spindle 13 and a tailstock 14 are coaxially provided on the shaft 11 so as to face each other in the left-right direction, and a workpiece W having a cylindrical work surface Wa is a spindle 13 and a tailstock 14. Both centers provided at 13
It is supported horizontally by a and 14a. The main shaft 13 is driven by a main shaft motor 15, and the workpiece W is rotationally driven by being engaged with the seed shaft 13 via a drive member 13b. A movable base 20 is supported on the bed 10 so as to be movable in the X direction, and a grinding stone base 30 that supports a grinding wheel 41 is supported on the movable base 20 so as to be rotatable in the ω direction. The grinding wheel base 30 is provided with a truing device 39 for reshaping the grinding surface 41a on the outer circumference of the grinding wheel 41. Instead of the illustrated truing device 39, a rotary truing device may be provided on the tailstock 14 on the table 11 that reciprocates in the left-right direction to perform truing.

Mainly as shown in FIGS. 3 and 4, the movable table 20 is supported by a guide rail 16 fixed on the bed 10 so as to be movable in a horizontal X direction orthogonal to the rotation axis of the workpiece W.
A reciprocating drive is performed by a servo motor 27 attached to the guide rail 16 via a feed screw 25 and a nut 26 screwed with the feed screw 25. A swivel shaft 21 formed by connecting a plurality of portions is vertically installed and fixed to the movable table 20 concentrically with the annular projection 20a formed on the upper surface. The whetstone base 30 is supported on the moving base 20 with the center hole 30a fitted to the swivel shaft 21 in a liquid-tight and rotatable manner.
A roller bearing is provided between the worm member 31 fixed to the lower portion and the swivel shaft 21, and the worm portion 31a at the lower end is the annular protrusion 20a.
Located within. A worm shaft 32, which meshes with the worm portion 31a, is rotatably provided on the moving table 20.
It is driven by the servo motor 34 via. Further, between the flange member 29 fixed to the upper end of the turning shaft 21 and the disk member 35 fixed to the upper surface of the grinding wheel head 30, an encoder 37 for detecting a relative turning angle between the moving table 20 and the grinding wheel head 30 is provided. It is provided. Accordingly, when the worm shaft 32 is rotated by the servo motor 34, the grindstone base 30 is swung in the ω direction around the turning shaft 21, and the turning angle is detected by the encoder 37.
Incidentally, the annular piston 22 provided in the annular cylinder 21b formed in the flange portion 21a on the upper part of the swivel shaft 21, the annular piston 22 is normally pressed by the spring 24 against the grindstone base 30 against the moving base 20, and both the bases 20,3.
Although the relative rotation of 0 is blocked, when the grindstone 30 is rotated by the servomotor 34, a joint member 65 described later is used.
The hydraulic pressure applied to the inside of the cylinder chamber 23 through the communication path 72 moves upwards against the spring 24, so that the grindstone base 30 can freely rotate.

As shown in FIGS. 2 and 3, a grinding wheel shaft 40 is rotatably mounted on one side of a grinding wheel stand 30 which is usually located on the table 11 side via a static pressure bearing (not shown). A grindstone 41 is fixed to the left end of 40, and a driven V pulley 45 is fixed to the right end. As shown, the motor installed on the wheel head 30
The reference numeral 46 drives the grinding wheel shaft 40 and the grinding wheel 41 via a driving V pulley 47, a V belt 48 and a driven V pulley 45.

As shown in FIG. 3, the grindstone base 30 is provided with an annular groove 61 on the inner periphery of the central hole 30a that fits with the turning shaft 21.
A communication hole 60 that communicates the lower part of the space 30b surrounding the 0 with the annular groove 61.
Are formed horizontally. On the moving table 20 and the turning axis 21,
As shown in FIG. 3 and FIG.
A recovery hole 62 communicating with the annular groove 61 is formed in the hole. The recovery hole 52 crosses the swivel axis 21, and both ends thereof directly open to the annular groove 61, and an upper hole 62a which opens to the upper hole 62a and descends vertically 2
It is formed by an intermediate hole 62b of the book and a lower hole 62c communicating with the lower ends of the intermediate holes 62b, extending horizontally, and opening on one side surface parallel to the moving direction X of the moving table 20.

As shown in FIG. 4, the joint member 65 has a lower hole 62c.
Is fixed to one side surface of the moving table 20 so as to cover the opening of the moving table 20. The joint member 65 has two large and small L-shaped communication holes 66,6.
7, one end of the thick communication hole 66 is connected to the lower hole 62c, and the other end is connected to a hydraulic oil tank (not shown) fixedly provided on the bed 10 via a flexible hose 67. . One end of the narrow communication hole 67 communicates with the communication passage 72, and the other end is provided with a pressure-resistant hose 69 connected to a pump (not shown) so that pressurized hydraulic oil from the pump is transferred to the cylinder below the annular piston 22. Room
It will be introduced within 23. In the present embodiment, both hoses 68, 69 are drawn out in parallel with the moving direction X of the moving table 20, and are passed through the flexible cable bear to eliminate the entanglement and entanglement due to the moving of the moving table 20. , So that it can be transformed smoothly.

Pressurized hydraulic oil from a pump (not shown) is supplied to each hydrostatic bearing to statically support the grindstone shaft 40, and then the space 30b.
It is discharged inside and accumulates in the lower part. The accumulated hydraulic oil is guided by gravity to the joint member 65 through the communication hole 60, the annular groove 61, and the recovery hole 62, and is recovered through the hose 68 into a hydraulic oil tank (not shown).

As shown in FIG. 2, the numerical controller 70 of the cylindrical grinder has a central processing unit 71, a memory 72, an interface 73 and a pulse distribution circuit 74 as main components. The encoder 37 is connected to the central processing unit 71 via the interface 73.
Counter 75 for counting pulses from the control panel 76 and CRT
A display device 77 is connected, and a drive unit 78 that drives the servomotor 34 is connected via a pulse distribution circuit 74. Although not shown, the central processing unit 71 includes servo motors 15 and 27, a truing device 39 servo motor,
Unillustrated servo motors that move the table 11 in the left-right direction are connected to each other via drive units. The operation panel 76 includes a manual pulse generator 76a for turning the wheel head 30 in the ω direction and an angle memory switch 76b. The turning angle of the grinding wheel head 30 turned by the operation of the manual pulse generator 76a is detected by the encoder 37 and is digitally displayed on the angle display means 77 composed of the CRT display device, and the turning angle is stored in the memory 72 by pressing the angle memory switch 76b. It will be remembered in.

When the grinding surface 41a of the grinding wheel 41 is tapered due to uneven wear, the grinding wheel head moves 30 in the X direction to approach the rotating workpiece W, and the grinding surface 41a of the grinding wheel 41 causes the working surface to move. W
The trial grinding of a is performed, and the taper of this work surface Wa is measured. This measurement is based on the width L of the work surface Wa and the diameters D ₁ , D at both ends.
_This is done by measuring ₂ . Using these respective values, the taper half-vertical angle α is calculated by the following equation.

α = tan ⁻¹ (D ₁ −D ₂ ) / 2L Next, hydraulic pressure is introduced into the cylinder chamber 23 from the communication passage 72 to raise the annular piston 22 to allow the swivel 30 to freely rotate. The manual pulse generator 76a of 76 is operated to operate the servomotor 34, and the grinding wheel head 30 is turned in a direction in which the taper of the work surface Wa is reduced. And angle display means 77
While viewing, the turning angle of the grindstone 30 displayed on it is α
In other words, when the position shown in FIG. 1B is reached, the operation of the manual pulse generator 76a is stopped to stop the turning of the grindstone table 36, and then the hydraulic pressure introduced from the communication passage 72 is shut off. The spring 24 through the annular piston 22
Thus, the grindstone base 30 is pressed against the moving base 20 to prevent turning.
Incidentally, since the position of the grinding surface 41a is slightly moved in the left-right direction by the turning of the wheel head 30, the table 11 is moved in the left-right direction by a servo motor (not shown) so that the positions of the grinding surface 41a and the working surface Wa coincide with each other. . Then, in this state, the grinding wheel 41
Is rotated to bring the grindstone base 30 closer to the rotating workpiece W, and the work surface Wa is ground by the grinding surface 41a.

In the state shown in FIG. 2 (b), among the generatrixes of the grinding surface 41a of the grinding wheel 41, those which come into contact with the work surface Wa have a high accuracy equivalent to the detection accuracy of the taper half apex angle α, and Since it is parallel to the rotation axis, the work surface Wa is ground cylindrically without taper. In addition, every time the grindstone base 30 is swiveled and fixed to the movable base 20, the angle memory switch is
Press 76b to memorize the turning angle of the wheel head 30, and when the wheel head 30 returns to the original angle and stops, the wheel head 30 is turned to the memorized turning angle when it is restarted and reproduced. To do so.

It should be noted that FIG. 1 shows the case where the trial grinding is performed shortly after the truing of the grinding surface 41a and the workpiece W is parallel to the grindstone shaft 40, and the grindstone base 30 is swung by the angle α around the swivel axis 21. However, according to the present invention, test grinding is performed in a state in which the grinding wheel shaft 40 is inclined with respect to the workpiece W by such a rotation, and the grinding wheel base 30 is moved by a half apex angle of the taper of the work surface Wa in that case. Is repeatedly performed so that is further turned. This repetition can be performed until the generating line of the grinding surface 41a of the grinding wheel 41 becomes uneven and the unevenness of the work Wa of the workpiece W reaches a predetermined allowable limit. Also, it is not always necessary to perform the test grinding specially, for example, when processing the same workpiece continuously, measure the taper as the trial grinding of the workpiece for each predetermined number of processing, and calculate the taper based on the measurement result by the above equation. The grindstone head 30 may be turned by a different angle.

According to the above-described embodiment, until the unevenness of the generatrix of the grinding surface 41a reaches a predetermined limit, without performing truing,
Since the taper of the work surface Wa caused by the tapered uneven wear of the grinding surface Wa can be removed with the high accuracy equivalent to the detection accuracy of the half-vertical angle α, the number of truing can be reduced. The grinding efficiency of the cylindrical work surface can be improved.

[Brief description of the drawings]

1 to 4 show an embodiment of a method for parallel grinding a cylindrical work surface according to the present invention. FIG. 1 is an explanatory diagram of the whole, and FIG. 2 is an example of a cylindrical grinder used for the execution. Structural drawing, No. 3
The figure is an enlarged sectional view taken along the line III-III in FIG. 2, and FIG. 4 is the IV in FIG.
-IV sectional view and FIG. 5 are explanatory views of an example of a conventional parallel grinding method for a cylindrical work surface. Explanation of code 30 …… Whetstone stand, 41 …… Grinding wheel, 41a …… Grinding surface, W ……
Workpiece, Wa ...... work surface, 77 ...... angle display unit (CRT display), D _1, D ₂ ...... diameter, L ...... axial width, alpha ...... half apex angle.

Claims (1)

(57) [Claims] 1. A method of parallel grinding a cylindrical work surface of a grinding wheel head, which supports a rotating grinding wheel, by rotating a workpiece relatively close to the grinding wheel wheel. Is capable of swiveling around a swivel axis orthogonal to the axis of rotation of the workpiece by a desired angle, and has angle display means for displaying the swivel angle of the grinding wheel head, and the workpiece that has been trial ground by the grinding surface of the grinding wheel. The axial width L of the work surface and the diameters D ₁ and D ₂ of both end portions are measured, the half apex angle α of the taper of the work surface is obtained based on the measured values, and the grinding stone head displayed on the angle display means is displayed. Grinding the work surface of the workpiece by the grinding surface of the grinding wheel after manually turning the wheel head by the half apex angle while looking at the turning angle in the direction of decreasing the taper around the turning axis. A parallel grinding method for a cylindrical work surface.