JP3090857B2 - Perimeter processing machine for stepped workpiece - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepped shaft outer peripheral machining machine which is driven by applying a thrust to a workpiece between a synchronously rotating spindle center and a tailstock center to clamp and rotate the workpiece.

[0002]

2. Description of the Related Art A spindle center and a tailstock center are placed in both center holes of a workpiece to position the workpiece, and the workpiece is supported and ground by the spindle center and the tailstock center stopped opposite to each other. In order to rotate the workpiece, a chuck that can be opened and closed is provided outside the center of the spindle, and the rotation of the spindle is transmitted to the workpiece through this chuck, and the grinding wheel is used to grind the workpiece using a grinding wheel. Boards are generally known.

[0003]

The conventional general cylindrical grinder requires a special jig such as a grinding wheel and a chuck.
Further, when the product number changes, the grinding wheel or the like must be replaced, which causes a time loss, and it is difficult to cope with small lot production.

[0004] Furthermore, in order to rotationally drive a workpiece, a margin for gripping of a chuck is required, so that a workpiece that requires processing to both ends requires at least two steps of processing, which is troublesome.

[0005] When the axial clamping force of the tailstock shaft center is increased, the center is seized. With a smaller clamping force, the workpiece cannot be positioned and the cutting speed becomes slower.
Furthermore, if the rotational speed of the workpiece is too high, the center hole will seize. Due to these restrictions, there is an inconvenience that the range of grinding condition selection is narrowed.

Further, in the traverse polishing method, a load is applied to the grinding wheel edge on the traverse advance side by an amount corresponding to a direct grinding margin. The actual grinding allowance for each rotation of the workpiece is not constant in the width direction of the grinding wheel. If the grinding wheel wear progresses in relation to the uncut amount for each rotation of the workpiece, the busbar shape will collapse, and if the required accuracy cannot be maintained, the grinding wheel must be re-corrected, that is, uneven grinding wheel wear and However, there are drawbacks such as the need to frequently correct the grinding wheel.

SUMMARY OF THE INVENTION An object of the present invention is to provide a stepped workpiece outer peripheral processing machine that addresses the above-mentioned problems.

[0008]

According to a first aspect of the present invention, there is provided a stepped workpiece peripheral processing machine for applying a thrust to a workpiece between a center of a spindle and a center of a tailstock to clamp the workpiece. Means for synchronously driving the main shaft and the tailstock shaft; and furthermore, the tailstock shaft is supported in a non-contact manner by a hydrostatic radial bearing as a guide bearing for both rotation and linear motion. , Provided in the hydraulic cylinder with a seal gap, when the workpiece is clamped, acts as a piston that presses the workpiece against the main spindle side by the clamping pressure,
When the workpiece is unclamped, a thrust plate that contacts the hydrostatic thrust bearing is provided. The second means is to swing a swing table whose swing center is on an extension of the center of the grindstone width by a fixed angle in both the left and right directions. By oscillating the grinding wheel composed of two conical surfaces each having a taper of a fixed angle to the left and right so as to traverse the workpiece leftward or rightward, the grinding wheel conical surface in the forward direction has a grinding action. It is characterized by being engaged in.

[0009]

A spindle head 2 having a spindle 15 provided with a hydrostatic bearing 16 provided at one end on the front side of a processing machine bed 1 and a core correspondingly supported by a hydrostatic radial bearing 20 in a non-contact manner. A tailstock head 3 having a push shaft 19 is provided, and one tailstock head 3 is provided on a slide table 4 which is slidably fitted on an axial table guide plate 5, and the two shafts 15,
The centers 15b and 19b provided at the end of the workpiece 19 are applied to both center holes of the workpiece W, and the non-contact supported tailstock shaft 19 is pushed leftward in the axial direction. The workpiece W is held by a clamp, and the workpiece W is synchronously driven by two servomotors and synchronously rotates while being clamped.

A workpiece W which rotates synchronously is orthogonal to the table guide plate 7 on a table guide plate 7 parallel to the table guide plate 5 and a cross feed table 6 slidably fitted to the table guide plate 5 and traversing in the X direction. A cross-feed table 6 and a grinding wheel table for infeed are provided by a grinding wheel 10 supported by a grinding wheel head 9 on a grinding wheel table 13 that is slid onto a Y direction table guide plate 8 and infeeds in the Y direction. The positions of the slide 13 and the slide table 4 are controlled by an NC program to move the grinding wheel 10 to the outer peripheral shape of the workpiece W to perform the processing.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a stepped shaft outer periphery processing machine according to the present invention, which will be described below with reference to the drawings.

A bed 1 is provided with a spindle head 2 at one end on the front side of the bed 1 and a tailstock shaft head 3 at the other end in correspondence with the spindle head 2. Provided on the slide table 4. The slide table 4 is slidably fitted on an axial table guide plate 5 so as to be movable. Further, on the rear side of the bed 1, a table guide plate 7 that slides and guides a cross feed table 6 that moves in the X direction to the left and right in parallel with the table guide plate 5 is provided horizontally. It traverses in the X direction.

Further, on the cross feed table 6, there is provided a table guide plate 8 in the Y direction orthogonal to the table guide plate 7, and on this table guide plate 8, a grindstone table 13 can be moved in the Y direction. To fit. A grinding wheel head 9 is attached to the front end side of the grinding wheel table 13, and a motor 12 for providing a grinding wheel 10 at one end and driving a rotating shaft 11 supported by the grinding wheel head 9 is attached to the rear side. It is.

Further, the rotating shaft 11 is provided with a grinding wheel 10
A pulley 11a is attached to the opposite end of the grinding wheel 10, and the motor 12 is connected to the pulley 11a by a belt 14, and the rotation of the grinding wheel 10 is transmitted by the driving of the motor 12.

The spindle head 2 provided on the bed 1 has a spindle 15 as shown in FIG.
Is a hydrostatic radial bearing 16 and a thrust plate 15a.
The main shaft 15 has one end connected to a servomotor 18 via a coupling 17. The tailstock shaft 19 of the tailstock shaft head 3 is supported in a non-contact manner by a radial static pressure radial bearing 20, and the tailstock shaft 19 is provided with a thrust plate 19a.

The left side of the thrust plate 19a faces the hydrostatic thrust bearing 21, and the right side is the hydraulic cylinder chamber 22.
Piston receiving surface pressure.

The pressure oil in the hydraulic cylinder chamber 22 is sealed to the left by a gap n at the outer diameter of the thrust plate 19a and to the right by a gap m at the outer diameter of the shaft. I'm muffled.

The oil in the cylinder chamber 22 is removed from the seal gap n.
Or, it flows out slightly outside through m. The left moving end of the slide table 4 of the tailstock head 2 is set so that the center 19b is located at the right end of the workpiece W.

When the slide table 4 is moved to the left end from the center of the workpiece W between the center 15b of the spindle 15 and the center 19b of the tailstock shaft 19, the tailstock shaft 19 moves rightward in the tailstock head 3. The thrust plate 19a is separated from the thrust bearing 21, and the tailstock shaft 19 presses the workpiece W by applying a thrust to the main shaft side by the pressure of the cylinder chamber 22.

Further, the opposite end of the tailstock shaft 19 on the center side is connected to a servomotor 18a via a coupling 17a to synchronize the rotation with the servomotor 18 on the main shaft 15 side.

The coupling 17a has a structure capable of absorbing an axial displacement between the tailstock shaft 19 and the servomotor 18a. When there is no workpiece W, the tailstock shaft 19 is positioned by the thrust bearing 21.

Next, a description will be given of a positioning mechanism of a slide table such as the slide table 4, the cross feed table 6, and the grindstone table 13 provided with the tailstock shaft head 3. Since each of the slide tables is positioned by the same mechanism, the slide table 4 will be described with reference to FIG.

A linear scale 23 is attached to the slide table 4 of the tailstock head 3. Further, a detector 24 for reading in correspondence with the linear scale 23 is provided on the bed 1. (Numerical control device) The difference (error signal) between the position command value of the 25 and the current table position is detected and output to the PI controller 26 (servo amplifier). The inside of a hydraulic cylinder 27 provided in the bed 1 is connected to a hydraulic source 30 via a differential pressure control type servo valve 29 to generate a thrust proportional to the error or to a value obtained by integrating the error. The slide table 4 is moved by the piston 31 connected to the slide table 4. Since the position of the slide table 4 at this time is detected by the linear scale 23, the slide table 4 stops at a position where the error becomes zero.

Next, the workpiece W which is clamped and held between the centers 15b and 19b provided on the spindle head 2 supporting the workpiece W and the spindle 15 and the tailstock shaft 19 of the tailstock spindle head 3 is held. Are synchronously driven by the servo motors 18 and 18a at both centers.
(Numerical control) The grinding wheel 10 for grinding this is controlled by the table guide plate 8 and the cross feed table 6 in the X and Y directions to grind the outer periphery of the workpiece W while traversing in the X direction (FIG. 6).

FIG. 7 shows a modification in which the outer peripheral surface is modified when the grinding wheel 10 is worn. A modified grinding wheel 31 is mounted on a mounting surface provided at the center 15b at the tip of the main spindle 15 with bolts 32. The spindle 15 to which the modified grinding wheel 31 is attached rotates at a preset number of revolutions, and
The X and Y positions of the grinding wheel 10 attached to 1 are controlled by a numerical control program, and the grinding wheel 10 is corrected by a cutting cycle using the grinding wheel table 13 and the cross feed table 6 and a traverse correction cycle.

The main shaft 15 and tailstock 19 are fitted with spigot portions of centers 15b and 19b at the ends thereof, and are mounted with bolts 33. The outer circumferences of the centers 15b and 19b and the shafts at the time of mounting are mounted. The center line has an error in manufacturing, mounting and the like, and is eccentric due to this error.
Therefore, the eccentricity is self-ground to correct the run-out.

For this purpose, a center-correcting grinding wheel 34 is mounted on the rotating shaft 11 of the grinding wheel 10 and the spindle center 15b and the tailstock shaft center 19b are started to rotate while the tailstock shaft 19 is moved forward to correct the center. Make a cut in the grinding wheel 34,
The conical surfaces of both centers 15b and 19b are ground (FIG. 8)
reference).

Next, the structure of the table guide boards 5, 7, 8 will be described. This structure comprises a reference guide 35 attached to the bed 1, a fixed guide 36 attached to the table, and an adjustment guide 37, which is divided into three parts, and an adjustment screw rod 39 which is screwed and adjusted to a fixed member 38 integrally attached to the table. After the adjustment guide 37 is tightened into the reference guide 35, the adjustment guide 37 is used integrally with the table by the fixing bolt 40. That is, the manufacturing is facilitated and the gap between the reference guide 35 and the reference guide 35 is easily adjusted (see FIG. 10).

Next, another embodiment of the stepped shaft outer peripheral processing machine will be described with reference to FIGS. This embodiment differs from the first embodiment in that a swing table 41 is provided on the grindstone table 13 so as to be swingable.

That is, on the front side of the bed 1, a spindle head 2 is arranged at one end and a tailstock shaft head 3 is arranged at the other end, as in the first embodiment. Numeral 3 is provided on a slide table 4 slidably fitted on a table guide board 5 provided on the bed 1.

Further, a table guide plate 7 for guiding the cross feed table 6 in the left and right directions in the X direction is provided horizontally on the rear side of the bed 1 in parallel with the table guide plate 5 and is movable by the table guide plate 7. A table guide plate 8 orthogonal to the table guide plate 7 is provided on the cross feed table 6, and the same grindstone table 13 as in the first embodiment is slid onto the table guide plate 8 in the Y direction. Is provided so as to be movable. Further, the grinding wheel table 13
A rocking table 41 is provided with a grinding wheel head 9 bearing a rotating shaft 11 of a grinding wheel 10 on the front end side and a motor 12 for driving the rotating shaft 11 via a belt 14 on the rear side. Has been posted. This swing table 41
The center of the swing is pivotally supported on the grinding wheel table 13 by a shaft 42 on the extension line of the center of the grinding width so as to be swingable. The swing table 41 is provided with stoppers 43 for stopping the grinding wheel 10 at positions where the swing table 41 has a constant swing angle in the left-right direction about the shaft 42.
a is provided. At this time, the grinding wheel 10 has a two-cone surface which is formed so as to extend to the both end surfaces of the grinding wheel by an inclination angle. When the grinding wheel moves right and left with respect to the workpiece W as shown in FIG. Traverse grinding is performed in a clockwise or clockwise direction. Grinding with this grinding wheel 10 does not cause a change in shape without modifying the grinding wheel 10 as in the prior art.

[0032]

As described above, according to the present invention, both the center of the main shaft and the tailstock shaft are synchronously driven by using a high-speed control servomotor. In addition to the structure that provides a clamping force, the workpiece rotates synchronously in a clamped state, so there is no need for a jig such as a chuck to rotate and the work can be done in one process, there is no trouble and time There is no loss. Also, since there is no slippage between the centers, the center holes are not seized even when clamped with a large force. Further, when a load torque is applied to the workpiece by grinding, the workpiece is held at the rotation speed of both centers by the frictional force of the center hole, and only the workpiece is not accelerated and rotated. Further, since the clamping is performed with a large force, the frictional force can be sufficiently increased.

In addition, a swing table having a swing center disposed on an extension of the center of the width of the grindstone is provided on the grindstone table, and a taper having only a grinding allowance is provided to avoid uneven wear of the grindstone during grinding. Using a grinding wheel to keep the wear constant, the grinding wheel's generatrix has a straight line, so there is no change even if grinding continues, and the grinding wheel is formed into two conical surfaces that are opposite to each other. Since the traverse grinding is performed alternately at an angle, the shape does not change without modifying the grinding wheel.

[Brief description of the drawings]

FIG. 1 is a front view in which a part of a stepped workpiece peripheral processing machine according to the present invention is stepped.

FIG. 2 is a plan view.

FIG. 3 is a partially enlarged cross-sectional view of the tailstock shaft shown in FIG. 1;

FIG. 4 is a slide table (cross feed table,
It is explanatory drawing of a (wheel table) positioning mechanism.

FIG. 5 is a principle diagram of a pressure control type servo valve.

FIG. 6 is an explanatory diagram of a workpiece grinding cycle.

FIG. 7 is an explanatory diagram of a grinding wheel correction cycle.

FIG. 8 is an explanatory diagram of correction of both centers.

FIG. 9 is a plan view of a slide table and a guide board.

FIG. 10 is a vertical sectional view taken along line XX of FIG. 9;

FIG. 11 is a plan view of another embodiment of a stepped workpiece peripheral processing machine.

FIG. 12 is an enlarged view of a part of FIG. 11 showing the inclination of the grinding wheel.

13 is an enlarged view of a part of the grinding wheel shown in FIG. 11 when a workpiece is being ground;

[Explanation of symbols]

 Reference Signs List 1 bed 2 spindle head 3 tailstock head 4 slide table 5, 7, 8 table guide board 6 cross feed table 9 grinding wheel head 10 grinding wheel 11 rotation axis 11a pulley 12 motor 15b, 19b center 13 grinding table table 14 belt 15 Main shaft 15a, 19a Thrust plate 16 Bearing 16a, 21 Hydrostatic thrust bearing 17 Coupling 18 Servo motor 19 Tail shaft 20 Hydrostatic radial bearing 22, 27 Hydraulic cylinder chamber 23 Linear scale 24 Detector 25 Numerical controller 26 P1 controller 29 Pressure Control Type Servo Valve 30 Hydraulic Power Source 31 Correction Wheel 32, 33 Bolt 34 Center Correction Wheel 35 Reference Guide 36 Fixed Guide 37 Adjustment Guide 38 Fixed Member 39 Adjustment Screw Rod 40 Fixed Bolt 41 Swing Tab 42 axis 43,43a stopper

Continuation of the front page (72) Inventor Tadashi Ishii 220-172, Wago-cho, Hamamatsu-shi, Shizuoka (56) References JP-A-2-124266 (JP, A) JP-A-5-200601 (JP, A) JP-A-61-241050 (JP, A) JP-A-3-273318 (JP, A) JP-A-2-88157 (JP, A) JP-A-50-45394 (JP, A) JP-A-1-306178 (JP, A) JP-A 5-37449 (JP, U) JP-A-58-143132 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B24B 5/04 B24B 41 / 06 B23B 23/00

Claims (2)

(57) [Claims] 1. A means for applying a thrust to a workpiece between a center of a spindle and a center of a tailstock to clamp the workpiece and synchronously driving the spindle and the tailstock. Non-contact support is provided by a hydrostatic radial bearing as a guide bearing for both the linear motion and the linear motion, and a back side of the tailstock shaft is provided in a hydraulic cylinder with a seal gap. A thrust plate acting as a piston pressed against the side, wherein when there is no workpiece, the tailstock shaft is positioned by a hydrostatic thrust bearing; 2. A grinding wheel having two conical surfaces each having a taper of a fixed angle by right and left swinging a rocking table having a center of rotation on an extension of the center of the width of the grinding wheel. The grinding wheel conical surface in the forward direction is involved in the grinding action when the workpiece is traversely ground leftward or rightward by oscillating the workpiece.
The stepped workpiece perimeter processing machine as described.