Method and device for simultaneous centreless cylindrical grinding of multiple workpieces

Abstract

A method and device for simultaneous centerless cylindrical grinding of multiple workpieces (11, 12, 13, 14), at least sections of which are rotationally symmetrical, the workpieces are arranged on a support apparatus (200) one behind the other between at least one grinding wheel (110) and at least one regulating wheel (120), and wherein the axis of rotation of the regulating wheel is inclined with respect to a horizontal plane extending parallel to the workpiece axes of rotation and the grinding wheel axis of rotation by an inclination angle (). During grinding the workpieces are arranged with a height offset relative to each other corresponding to at least a quarter of the inclination angle () of the axis of rotation of the regulating wheel with respect to the parallel plane to render the respective bearing angles () of the workpieces on the inclined regulating wheel consistent.

Claims

1. A method for simultaneous centreless cylindrical grinding of multiple workpieces at least sections of which are rotationally symmetrical, wherein the workpieces for grinding are arranged one behind the other in the direction of the workpiece axes of rotation on a support apparatus between at least one grinding wheel and at least one regulating wheel, and wherein the axis of rotation of the regulating wheel is inclined by an inclination angle () with respect to a particularly horizontal plane extending parallel to the workpiece axes of rotation and the grinding wheel axis of rotation, wherein during grinding the workpieces are disposed with a height offset with respect to each other corresponding to at least a quarter, particularly at least half, preferably at least three quarters of the inclination angle () of the regulating wheel axis of rotation relative to the parallel plane so that the respective bearing angles () of the workpieces on the inclined regulating wheel are rendered consistent.

2. The method according to claim 1, wherein during grinding the workpieces are disposed one behind the other on the support apparatus with a height offset corresponding to the inclination angle () of the regulating wheel in such manner that a notional connecting line (LS) through the geometrical centres of gravity (S) of the workpieces extends parallel to the inclined regulating wheel axis of rotation; and/or during grinding the workpieces are disposed one behind the other on the support apparatus with a height offset corresponding to the inclination angle () of the regulating wheel axis of rotation in such manner that each of the workpieces have substantially the same bearing angle () on the inclined regulating wheel.

3. The method according to claim 1, wherein the regulating wheel is dressed before grinding by means of a height-adjustable dressing device at the places where the workpieces bear on the regulating wheel during grinding according to their height-adjusted arrangement.

4. A device for simultaneous centreless cylindrical grinding of multiple workpieces at least sections of which are rotationally symmetrical, for carrying out the method according to claim 1, with at least one grinding wheel and at least one regulating wheel, between which the workpieces can be disposed for grinding on a support apparatus one behind the other in the direction of the axes of rotation and wherein die axis of rotation of the regulating wheel is tiltable about an inclination angle () with respect to a particularly horizontal plane which extends parallel to the workpiece axes of rotation, and the grinding wheel axis of rotation, wherein the support apparatus is constructed in such manner that during grinding the workpieces are arranged with a height offset with respect to each other that corresponds to at least a quarter, particularly at least half, preferably at least three quarters of the inclination angles () of the regulating wheel axis of rotation relative to the parallel plane, so that the respective bearing angles () of the workpieces on the inclined regulating wheel can be made consistent.

5. The device according to claim 4, wherein the support apparatus is constructed in such manner that during grinding a notional connecting line (LS) through the geometrical centres of gravity (S) of the workpieces is aligned parallel to the inclined axis of rotation of the regulating wheel; and/or the support apparatus is constructed in such manner that during grinding the workpieces are arranged with a height offset with respect to each other corresponding to the inclination angle () of the axis of rotation of the regulating wheel in such manner that each workpiece bears on the inclined regulating wheel at substantially the same bearing angle ().

6. The device according to claim 4, wherein the support apparatus is constructed so as to be height-adjustable as a whole and/or that the support apparatus is constructed so as to be replaceable as a whole.

7. The device according to claim 4, wherein the support apparatus is equipped with multiple supports arranged one behind the other in the direction of the axes of rotation thereof to support the multiple workpieces, which supports are arranged with height offset relative to each other corresponding to the inclination angle () of the regulating wheel axis of rotation, in particular that the support apparatus is designed in step-like manner to support the multiple workpieces and/or that the supports are arranged one behind the other in a stepped configuration.

8. The device according to claim 7, wherein at least one, preferably each of the multiple supports is constructed so as to be separately height-adjustable, in particular that at least one, preferably each of the multiple supports is constructed as a separately height-adjustable support element.

9. The device according to claim 7, wherein at least one, preferably each of the multiple supports is separately tiltable out of the horizontal with respect to the grinding wheel axis of rotation, in particular that at least one, preferably each of the multiple supports is constructed as a support element that is separately tiltable out of the horizontal with respect to the grinding wheel axis of rotation.

10. The device according to claim 7, wherein at least two of the supports are fixedly arranged with a height-offset with respect to each other corresponding to the inclination angle () of the regulating wheel axis of rotation, in particular that they are not separately height-adjustable.

11. The device according to claim 4, wherein the grinding wheel comprises multiple partial grinding wheels arranged one behind the other on the grinding wheel axis of rotation, and the regulating wheel comprises multiple partial regulating wheels arranged one behind the other on the regulating wheel axis of rotation, wherein preferably one partial grinding wheel and one partial regulating wheel are provided for each workpiece to be ground.

12. The device according to claim 4, wherein the device has at least one limit stop for each workpiece, on which the workpiece bears in the direction of the axis of rotation of the workpiece during grinding.

13. The device according to claim 4, wherein the device is equipped with at least one movable, particularly height-adjustable dressing device for dressing the at least one regulating wheel and/or the at least one grinding wheel, in particular in order to dress the regulating wheel before grinding at the places where the workpieces bear on the regulating wheel according to their height-offset arrangement.

14. The device according to claim 4, wherein the grinding wheel axis of rotation extends substantially parallel to the workpiece axes of rotation for inline plunge grinding or that the grinding wheel axis of rotation is aligned at an angle to the workpiece axes of rotation for offset plunge grinding.

Description

(1) Further details of the invention and particularly an exemplary embodiment of the invention will be explained in the following with reference to the accompanying drawing. In the drawing:

(2) FIG. 1 shows a front view of one possible embodiment of a grinding device according to the invention for simultaneous centreless cylindrical grinding of multiple workpieces;

(3) FIG. 2 shows a horizontal cross section through the grinding device according to FIG. 1; and

(4) FIG. 3 shows a vertical cross section through the grinding device according to FIG. 1.

(5) FIGS. 1 to 3 show one possible embodiment of a grinding device 1 according to the invention for simultaneous centreless cylindrical grinding of multiple workpieces 11, 12, 13, 14. In the present case, workpieces 11, 12, 13, 14 are identical, rotationally substantially symmetrical cylindrical bodies which are to be ground to receive a diameter of uniform dimension and roundness in the round grinding method of the invention with the aid of the grinding device 1 according to the invention.

(6) FIGS. 1 to 3 are diagrammatic representations of the centreless cylindrical grinding process. Workpieces 11, 12, 13, 14 are arranged one behind the other in the direction of the workpiece axes of rotation 11.1, 12.1, 13.1, 14.1 and are supported on a fence-like support apparatus 200 in the grinding gap between grinding wheel 110 and regulating wheel 120. In the present embodiment, both the regulating wheel 120 and the grinding wheel 110 comprise one partial regulating wheel 121, 122, 123, 124 and one partial grinding wheel 111, 112, 113, 114 for each workpiece 11, 12, 13, 14. Each partial regulating wheel 121, 122, 133, 124 and each partial grinding wheel 111, 112, 113, 114 is arranged on a common axis of rotation of the regulating wheel 120.1 or a common axis of rotation of the grinding wheel 110.1 respectively, by means of which the partial grinding wheels and partial regulating wheels may be caused to rotate. In the embodiment shown of the grinding device 1 according to the invention, all workpieces 11, 12, 13, 14 are positioned above the connecting line between the grinding wheel axis of rotation 110.1 and the regulating wheel axis of rotation 120.1, i.e. grinding is performed above centre. Tangents T on the partial regulating wheels 121, 122, 123, 124 in the contact point of workpieces 11, 12, 13, 14 form bearing angle relative to the vertical or plumb L of the workpieces 11, 12, 13, 14 on the respective partial regulating wheels 121, 122, 133, 124, which angle is critical for determining the achievable roundness of workpieces 11, 12, 13, 14.

(7) During the grinding process, workpieces 11, 12, 13, 14 are driven by the slowly rotating partial regulating wheels 121, 122, 133, 124 and machined by the relatively faster rotating partial grinding wheels 111, 112, 113, 114. The support apparatus and partial grinding wheels 111, 112, 113, 114 support the workpiece over at least a part of its length and absorb the forces that are generated by machining. The grinding device 1 presented here is used for inline plunge grinding. For this, the grinding wheel axis of rotation 110.1 and the regulating wheel axis of rotation 120.1 are aligned side by side and substantially parallel. However, the axis of rotation of regulating wheel 120.1 is inclined with respect to a horizontal plane extending parallel to the grinding wheel axis of rotation 110.1 and to the workpiece axes of rotation 11.1, 12.1, 13.1, 14.1 by an inclination angle . For plunge grinding, inclination angle typically has a value of about 0.5. In this way a thrust in the direction of the workpiece axes of rotation 11.1, 12.1, 13.1, 14.1 is exerted on workpieces 11, 12, 13, 14 by the rotation of partial regulating wheels 121, 122, 123, 124, which thrust is used to press workpieces 11, 12, 13, 14 against a respective (axial) limit stop 311, 312, 313, 314 to hold the workpieces fixedly in the axial direction in grinding device 1.

(8) If workpieces 11, 12, 13, 14 were arranged at the same height with respect to the horizontalas is standard in the prior artthe inclination of the regulating wheel axis of rotation 120.1 would cause the workpieces to bear on the partial regulating wheels 121, 122, 123, 124 at different bearing angles in each case. However, in the context of the invention it was found that this results in inconsistent grinding results, particularly inconsistent roundnesses and diameters in workpieces 11, 12, 13, 14 that are ground simultaneously in one grinding cycle. To counteract this. It is provided according to the present invention to arrange the workpieces 11, 12, 13, 14 in the grinding gap with a height offset relative to each other corresponding to the inclination angle of the regulating wheel axis of rotation 120.1, and preferablyas in the presentin such manner that each workpiece has substantially the same bearing angle on the inclined regulating wheel 12, particularly, that the bearing angles of all workpieces 11, 12, 13, 14 on the respective partial regulating wheels 121, 122, 133, 124 are the same, i.e. identical. For this, the workpieces 11, 12, 13, 14as shown in FIG. 3are disposed one behind the other and with a height offset on support apparatus 200 in such manner that a notional connecting line LS through the geometrical centres of gravity S of workpieces 11, 12, 13, 14 extends parallel to the inclined regulating wheel axis of rotation 120.1.

(9) The embodiment of grinding device 1 represented here shows a possible and particularly advantageous variant of support apparatus 200 for the purpose of achieving the inventive height-offset arrangement of workpieces 11, 12, 13, 14, corresponding to inclination angle of regulating wheel axis of rotation 120.1. For each of the workpieces 11, 12, 13, 14 the support apparatus has one support 211, 212, 213, 214, each with a support surface which rises transversely to the grinding gap towards grinding wheel 110, on which the corresponding workpieces 11, 12, 13, 14 are supported during grinding. The various supports 211, 212, 213, 214 are offset from each other in the manner of steps corresponding to inclination angle of the regulating wheel axis of rotation 120.1 axially, i.e. along the grinding gap. In particular, the supports 211, 212, 213, 214 in the present embodiment are designed as support elements 201, 202, 203, 204 which are separately height-adjustable (indicated by the double-headed arrows in FIG. 3). In this way, it is advantageously possible to make fine adjustments to the height offset of the individual workpieces 11, 12, 13, 14 and/or adapt support apparatus 200 for simultaneous grinding of workpieces with differing geometries. All support elements 201, 202, 203, 204 are arranged on a common support base 230, which itself is designed to be height-adjustable as a unit, so that the height of the entire support apparatus 200 is adjustable as a unit. Set screws or actuators for example may be provided for adjusting the height of support elements 201, 202, 203, 204 and support base 230.

(10) In order to be able to dress regulating wheel 120 or partial regulating wheels 121, 122, 123, 124 along the regulating wheel axis of rotation 120.1 at different heights corresponding to the height-offset arrangement of the workpieces, it may be provided that grinding device 1 is equipped with a height-adjustable dressing device (not shown here). Of course, in addition to the height adjustment capability the dressing device may also be constructed such that it can be displaced and advanced axially along the grinding gap and/or horizontally. It may also be provided for the grinding wheel 110 or the partial grinding wheels 111, 112, 113, 114 to be dressed before the grinding operation, preferably with the aid of the height-adjustable dressing device, and also at the places where the workpieces bear on the grinding wheel during grinding corresponding to their height-offset arrangement. In particular it may be provided that grinding wheel 110 or the partial grinding wheels 111, 112, 113, 114 are dressed to different diameters along the grinding wheel axis of rotation 110.1, to ensure that the grinding wheel 110 or partial grinding wheel 111, 112, 113, 114 are each brought into optimal grinding contact with workpieces 11, 12, 13, 14 taking into account the height-offset arrangement thereof.