JPH0420744B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for measuring the position of the grinding center of a spherical workpiece in a groove machining machine, such as an inner ring of a ball joint used in an automobile.

Background of the technology In recent years, as automobiles have become more sophisticated, high-performance, and resource-saving, four-wheel independent suspension systems are increasingly being adopted not only for FF cars but also for FR cars. requested. However, the inner ring, which is the lifeblood of a ball joint, has a complex special shape as shown in Figure 1, and in order to achieve high quality, the accuracy of indexing the grooves Wa to Wf of the product is extremely important. Accuracy is affected by more than 10 factors such as pre-processing accuracy, for example, error in outer sphere center height, error in outer sphere diameter, etc. Therefore, the applicant proposed in Japanese Patent Laid-Open No. 143906/1983 a holding device with a self-centering function for the inner ring which is not affected by the outer ball center height error and the outer ball diameter error of the pre-processing. However, with a ball joint inner ring, the center of the outer sphere of the inner ring and the center of the groove bottom diameter are different, so it is difficult and time-consuming to measure the dimension from the bottom of the inner ring to the center of the groove bottom diameter with high precision. There was an inconvenience.

Purpose Therefore, this invention was made in view of the above,
The present invention aims to provide a method for measuring the grinding center position of a spherical workpiece by which the groove bottom center can be easily determined on-site by using a special grindstone correction setup and a test piece.

Solution: A disc-shaped grinding wheel correction setup having an approximately outer diameter dimension of the spherical workpiece and a diamond for correcting the outer diameter of the grinding wheel is held in place of the spherical workpiece in a holding device of a groove machining machine for the spherical workpiece. After adjusting the outer periphery of the grinding wheel to be parallel to the grinding wheel axis, in place of the grinding wheel correction setup, a notch is provided on a disc-shaped pedestal having approximately the outer diameter of the spherical workpiece so that the diameter after grinding with the grinding wheel can be measured. After holding the center measurement setup that has formed a circular protrusion and grinding the outer diameter of the protrusion, the height M of the center measurement setup from the bottom surface of the pedestal and the cutout circular diameter D of the protrusion are determined.
The distance from the bottom surface of the pedestal to the center of the grinding circle is determined based on this value.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. First, the proposed ball joint holding device will be explained. A grinding wheel head rotatably supports a grinding wheel 1 for R-groove grinding, a headstock rotatably supports a main spindle 2 on a table of a grinding machine to which cutting feed is given, and a tailstock 3 concentric with the main spindle 2 is mounted on a bearing 4. A tailstock 6 is mounted which supports a sleeve 5 which is rotatably supported by a shaft so as to be slidable in the axial direction.
The head 7 is inserted into the through hole drilled in the center of the tailstock 3.
The operating shaft 7 having a shape a is prevented from rotating and is rotated together with the tailstock shaft 3 fitted so as to be slidable in the axial direction. A compression spring 8 is interposed between a blind hole 7b opened and drilled at the rear end of the operating shaft 7 and a lid (not shown) fastened to the rear end of the tailstock shaft 3, so that the operation can be performed at all times. The shaft 7 is urged to be pushed out toward the main shaft.
A piston rod 9 is screwed into the center of the blind hole 7b, and the piston rod 9 passes through the lid at the rear end of the central shaft 3, and the piston part fits into a cylinder (not shown) provided in the sleeve 5. The operating shaft 7 is moved back through the piston rod 9 when pressure fluid is sent to the cylinder. And again, the head 7 is attached to the operating shaft 7.
Push rods 10a and 10b are installed at a position a predetermined distance above and below the axis of the tailstock shaft 3 in parallel with the axis. The mounting table 11 has a mounting surface 11a on which the flat surface of the ball joint inner ring W, which is a workpiece, is placed, and H-shaped mounting portions are provided at right angles on both ends of the mounting surface 11. and to the end face of the tailstock shaft 3 at the tailstock shaft side mounting portion 11c with stop bolts, so that when the main shaft is rotated by a drive device (not shown), the tailstock shaft 3 and the tailstock shaft 3 are fixed together. be rotated. When the ball joint inner ring W is placed on the mounting surface 11a, the center of rotation of the inner ring W is aligned with the center of rotation of the main shaft. The spindle side mounting portion 11b is formed with an arcuate surface 11d that is slightly larger than the diameter of the outer sphere of the inner ring W so as to surround the ridges on the left half of the ball joint inner ring W, three ridges in this example. A positioning pin 17a fitted into the groove projects from the arcuate surface 11d toward the center of the outer sphere, and a space is also formed in which a swinging rod 12 for centering and gripping the inner ring W of the ball joint is attached. This swinging rod 12 is the mounting part 11
The outer spherical part of the ball joint inner ring W is supported by a pivot shaft 13 provided on b and parallel to the mounting surface 11a and perpendicular to the axis of the main shaft 2, and is placed on the end of the arm 12a above the pivot point. A gripping claw 14 is fixed to the arm 12b below the pivot point, and the arm 12b is slidably fitted into a blind hole 2a drilled in the main shaft 2, and is always attached in the projecting direction by a spring 15. The pusher 16 is forced to open counterclockwise in FIG. 2 until it hits the stopper 17b. The end of the lower arm 12b is in contact with a pressing rod 18 that is slidably provided on the lower side of the mounting surface 11a on the axis of the push rod 10b under the operation shaft head 7a in the gripping direction. It is becoming more and more popular.

On the other hand, the mounting portion 11c on the tailstock shaft side is provided with a space where the operating shaft head 7a faces, and a positioning plate 19 for indexing the machining groove of the inner ring W is attached to the surface facing the ball joint inner ring W. This indexing guide plate 19 is located at 3 on the right half of the ball joint inner ring W.
It has an arcuate surface that surrounds the mountain and is equal to or slightly larger than the diameter of the outer sphere. The attachment portion 11c on the tailstock side also supports a pivot shaft 20 at both ends, which is perpendicular to the axis of the main shaft 2, that is, parallel to the pivot shaft 13 of the swinging rod 12. A moving rod 21 is pivotally supported. The swinging rod 21 has a circular arc surface having the same shape as the indexing guide plate 19, and the gripping claws 22 and 23 that press the peak of the outer sphere at symmetrical positions with respect to the axis of the main shaft 2 are attached to the swinging rod. It is fixed so as to be in contact with the 12 gripping claws 14 at the same height. The swinging rod 21 is urged clockwise by a spring 24 so as to be open at all times, and its back surface is in contact with an upper push rod 10a installed in the head 7a of the operating shaft 7. The swinging rods 12 and 21 are mutually turned inward by the push rods 10a and 10b of the operating shaft 7 pushed out by the spring 8, and the amount of movement of the gripping claw 14 of the swinging rod 12 and the gripping claw 22, The ball joint inner ring W is gripped while being aligned with the movement amount of 23. As shown in Fig. 3, the grindstone correction setup A attached to this holding device is a disc pedestal Aa whose height is the same as the height of the inner ring W, and the large upper surface Ab is a surface in contact with the outer diameter of the inner ring W. Hot gripping claws 14, 2
2 and 23 are formed at abutting positions. A diamond tool T is mounted so as to protrude in the lateral radial direction of the pedestal Aa. As shown in Fig. 4, the disc-shaped pedestal Ba and surface Bb of center measurement setup B have the same dimensions and shape as pedestal Aa of corrected setup A, and furthermore, a circular protrusion Bc is formed at right angles to the pedestal surface on the diameter. A cutout Bd for grinding is cut on both sides of the part that intersects with the outer part of the pedestal Ba, and the circular protrusion Bc forms a cutout circle slightly larger than a semicircle, and the diameter of this circle can be measured after grinding. It has size and width.

Next, a method for measuring the groove bottom diameter center will be described using the grindstone correction setup A and the center measurement setup B. First, when pressure fluid is supplied to a cylinder (not shown) and the operating shaft 7 is moved backward, the push rods 10a, 10b are moved back, and the force of the springs 15 and 24 causes both the swinging rods 12, 21 to move, 22, 23 are opened outward. With the mounting surface 11a of the mounting table 11 facing upward, the turning grindstone correction setup A is placed with the diamond T facing the grindstone 1. By cutting off the supply of pressure fluid to the cylinder and dropping it to the discharge side, the operating shaft 7 is pushed out by the force of the spring 8. The push rod 10a pushes the back side of the swinging rod 21 by the same amount, and the push rod 10b pushes the lower arm of the swinging rod 12 by the same amount through the pressing rod 18.
Therefore, the swinging rods 12 and 21 both turn toward the correction setup A side, the gripping claws 14, 22, and 23 move by the same amount as described above, and the setup A is automatically aligned using the outer sphere as proof. and grasped. When gripping is completed, the whetstone 1 is rotated, the whetstone head is moved forward, and the table is reciprocated from side to side.
Dress the outer periphery of the grindstone 1 with a diamond tool T as shown in FIG. 5 to form a linear surface parallel to the grindstone axis. When the correction is completed, pressure fluid is sent to a cylinder (not shown), the operating shaft 7 is moved back, and the gripping claws 14,
Open 22 and 23 and place setup B for center measurement on mounting table 11.
Place the setup on the mounting surface 11a of the wheel so that the circular protrusion Bc is perpendicular to the grinding wheel axis, grip the setup in the same way, rotate the spindle 2, and place the setup B for center measurement.
externally ground with grindstone 1 as shown in Figure 6. After completing the field test, remove the center measurement setup B and use the measuring device to measure the 7th
As shown in the figure, measure the distance M from the bottom of the pedestal to the top of the circular protrusion Bc and the diameter D of the circular protrusion Bc.
The distance N between the center of the groove bottom and the bottom surface of the pedestal is determined by calculating -D/2. A comparison is made to see if the N, that is, the center height obtained in this way matches the design value. As a result of the comparison, if the value of N is smaller than the design value, the mounting surface 11a
Correct by (design value - N). On the other hand, if it is larger than the design value, the mounting surface 11a is made higher by (design value - N). After correcting the mounting surface in this way, by mounting and grinding the ball joint inner ring W, it is possible to process the part with the center height as designed.

Effects As detailed above, the present invention attaches a grindstone correction setup to a holding device for a spherical workpiece such as a ball joint, grinds the grindstone in a straight line, and adjusts the groove bottom based on the measured value of the ground surface. Since the center height is calculated, the center position can be determined easily, inexpensively, and accurately on site by creating a simple setup, which has the feature of improving work efficiency and product accuracy. It is.

[Brief explanation of drawings]

Figure 1 is a horizontal sectional view of the holding device for a spherical workpiece.
2 is a vertical cross-sectional view, FIG. 3 is a perspective view of the setup for grinding wheel correction, FIG. 4 is a perspective view of the setup for center measurement, and FIG. 5 is a diagram of the state of correction in the setup for grinding wheel correction.
FIG. 6 is a diagram showing the grinding state of the setup for center measurement, and FIG. 7 is a diagram showing the measuring section. 1...Whetstone, 2...Main spindle, 3...Tailstock spindle, 11
...Placement table, 14, 22, 23...Gripping claw, A...
...Setup for grinding wheel correction, B...Setup for center measurement.

Claims (1)

[Claims] 1 The workpiece holder of a groove processing machine for spherical workpieces such as the inner ring of a ball joint holds a grinding wheel correction setup with a diamond that has approximately the same outer diameter as the workpiece, and the outer periphery of the grinding wheel is corrected to be parallel to the grinding wheel axis. After that, the center measurement setup, which has a disk-shaped protrusion that has approximately the same outer diameter as the workpiece, is replaced with the grindstone correction setup and is held in the workpiece holder, the disk-shaped protrusion is ground, and the measurement is carried out. A method for measuring the grinding center position of a spherical workpiece, characterized in that the height of the center of the disc is determined from the height of the disc during setup and the diameter of the disc.