Rotary dressing apparatus

[57] ABSTRACT

A grinding wheel provided with first and second tapered outer peripheral surfaces intersecting with each other at a predetermined angle and a reentrant curved surface on the outer edge of the second tapered outer peripheral surface is dressed by rotary dressing appara tus having first and second working rolls. The rotary dressing apparatus comprises a feed carriage slidably mounted on the grinding wheel carriage, means for feeding the feed carriage toward the grinding wheel, a slide base slidably mounted on the feed carriage, means for moving the slide base in a direction perpendicular to the path of the movement of the slide carriage in parallel with a tangent line of the outer periphery of the grinding wheel, a first dressing head including the first working roll and driving means for totaling the same, the first working roll having a cup shaped configuration including an annular working surface adapted to work the first tapered outer peripheral surface of the grinding wheel, means for mounting the first dressing head on the slide base to be tiltable about a first axis perpendicular to the path of the movement of the slide base, a second dressing head including the second working roll and driving means for rotating the same, the second working roll having a cylindrical working surface adapted to work the second tapered outer peripheral surface, the outer edge of the cylindrical working surface of the second working roll being adapted to work the reentrant curved surface of the grinding wheel, and means for mounting the second dressing head on the slide base to be tiltable about a second axis substantially parallel with the first axis.

Claims, 4 Drawing Figures

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Patented July 24, 1973

3,747,584

Sheets-Sheet 1

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Patented July 24, 1973

3,747,584

Sheets-Sheet 2

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X

3,747,584

ROTARY DRESSING APPARATUS

BACKGROUND OF THE INVENTION

This invention relates to rotary dressing apparatus for dressing a grinding wheel having first and second tapered outer peripheral surfaces intersecting with each other at a predetermined angle and a reentrant curved surface at one edge of the second tapered outer peripheral surface by means of a cup shaped diamond roll and a cylindrical diamond roll (hereinafter, often called as first and second working rolls).

When grinding workpieces, dependent upon their configuration, it is necessary to sumultaneously work two surfaces of the workpiece which intersect with each other at a predetermined angle by means of a single grinding wheel. Such a case arises when it is desired to simultaneously grind the side wall 2 and the bottom wall 3 of an inner race 1 of a bearing, as shown in FIG. 1. As diagrammatically shown in FIG. 1, however, a conventional grinding wheel 5 has been constructed to have two tapered outer peripheral surfaces 6 and 7 adapted to simultaneously work the said wall 2 and bottom wall 3, respectively. The edge 4 of the side wall 2, therefore, engages the outer peripheral surface 6 at an acute angle. Consequently, when finished inner reces are conveyed to a container through a chute or the like conveyor means, these acute edges 4 may damage the finished surfaces of another inner races. The outer peripheral surfaces of the grinding wheel utilized to grind such a workpiece has been dressed by means of a onepoint diamond dresser which is moved in accordance with a template of a requisite configuration. However, this method is not only inefficient but also needs an appropriate template for each form of the workpiece, that is a template for one workpiece can not be used to work another workpieces having side and bottom walls intersecting at different angles.

SUMMARY OF THE INVENTION

Accordingly, it is an object of this invention to provide improved rotary dressing apparatus capable of dressing a grinding wheel for simultaneously working the side and bottom walls of a workpiece of the type referred to above and for eliminating the acute edge of the side wall.

Another object of this invention is to provide improved rotary dressing apparatus capable of simultaneously dressing first and second tapered outer peripheral surfaces and a reentrant curved surface on the outer edge of the second tapered outer peripheral surface of a grinding wheel by moving a first working roll having an annular working surface adapted to work the first tapered outer peripheral surface and a second working roll having a cylindrical working surface adapted to work the second tapered outer peripheral surface in a direction tangential to the periphery of the grinding wheel.

Still another object of this invention is to provide new and improved rotary dressing apparatus for dressing a grinding wheel including means for tilting in the vertical direction the axis of the cup shaped working roll for finishing the first tapered outer peripheral surface of the grinding wheel to have flat, concave or convex configuration and means for adjusting in a horizontal plane the angular positions of the axes of the first and second working rolls.

According to this invention there is provided rotary dressing apparatus for dressing a grinding wheel which is mounted on a grinding wheel carriage and is provided with first and second tapered outer peripheral surfaces intersecting with each other at a predetermined angle and a reentrant curved surface on the outer edge of the second tapered outer peripheral surface with first and second working rolls, characterized by comprising a feed carriage slidably mounted on the grinding wheel carriage, means for feeding the feed carriage toward the grinding wheel, a slide base slidably mounted on the feed carriage, means for moving the slide base in a direction perpendicular to the path of the movement of the slide carriage in parallel with a tangent line of the grinding wheel, a first dressing head including the first working roll and driving means for rotating the same, the first working roll having a cup shaped configuration including an annular working surface adapted to work the first tapered outer peripheral surface of the grinding wheel, means for mounting the first dressing head on the slide base to be tiltable about a first axis perpendicular to the path of the movement of the slide base, a second dressing head including the second working roll and driving means for rotating the same, the second working roll having a cylindrical working surface adapted to work the second tapered outer peripheral surface, the outer edge of the cylindrical working surface of the second working roll being adapted to work the reentrant curved surface of the grinding wheel, and means for mounting the second dressing head on the slide base to be tiltable aboout a second axis substantially parallel with the first axis.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which :

FIG. 1 shows a diagrammatic sectional view showing the manner of working a workpiece, such as an inner bearing race with a prior art grinding wheel having two tapered outer peripheral surfaces intersecting with each other at a predetermined angle ;

FIG. 2 is a view similar to FIG. 1 but showing the manner of working an identical workpiece with a grinding wheel dressed by the improved rotary dressing apparatus embodying the invention ;

FIG. 3 is a side elevational view, partly in section, showing a grinding wheel and improved dressing apparatus constructed according to the teaching of this invention and

FIG. 4 is a plan view, partly in section, of the dressing apparatus shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 3 and 4, the dressing apparatus shown therein comprises a base 10 upon which a grinding wheel carriage 11 is pivotally mounted by means of a pivot pin 12 to be tiltable in the clockwise direction as viewed in FIG. 3. On the carriage 11 is rotatably mounted a grinding wheel 13 having first and second inclined outer peripheral or working surfaces 13α and 13b intersecting with each other at a predetermined angle and a reentrant curved surface 13c on one side edge of the second working surface 13b. The first tapered outer peripheral surface 13α is used to grind the bottom wall 3 of the inner race 1 shown in FIG. 2

3,747,584 whereas the second tapered peripheral surface 13b and reentrant curved surface 13c are used to grind the side wall 2 and curved edge 4, respectively, of the workpiece. A shaft 14 is secured to the side wall of grinding wheel carriage 11. A base plate 15 is rotatably mounted on shaft 14 and the base plate is secured to any desired adjusted position by means of a plurality of bolts 17 extending through elongated slots 16 of base plate 15.

A letter U-shaped notch 18 is formed on the rear (right hand) end of base plate 15 to accommodate adjusting bolts 19α and 19b threadedly engaged with a block 20 secured to grinding wheel carriage 11 whereby base plate 15 can be rotated about shaft 14 for any desired angle by adjusting bolts 19α and 19b. On one side of base plate 15 is secured a supporting base 22 having a slide surface 21 extending in parallel with a line X—X which passes through the axis of grinding wheel 13 and intersects at right angles with the path of movement of a slide base 23 which will be described later in detail. A feed carriage 25 having slide base 23 and feed means 24 is mounted on slide surface 21. The feed carriage 25 receives a threaded feed shaft 27 which is operated by conventional automatic feed means 26 mounted on the rear end of the supporting base 22 and containing a ratched mechanism or the like, not shown so as to slide the feed carriage 25 on slide surface 21 in the direction in parallel with line X—X. Feed shaft 27 can also be operated by a manually operated hand wheel 28. On the front side of feed carriage 25 is formed a slide surface 29 which extends at right angles with respect to line X—X and in parallel with a line Y—Y passing through the axis of the grinding wheel 13 so as to slidably support slide base 23. The lower end of the piston rod 32 of a piston 31 received in a cylinder 30 of the feed means 24 is secured to a supporting plate 33 which is secured to the lower end of slide base 23. Accordingly, slide base 23 is moved along slide surface 29 in a direction parallel with line Y—Y by admitting oil under pressure into the upper or lower chamber of cylinder 30.

A supporting ledge 34 is integrally formed at the upper fore end of slide base 23 to support a letter Lshaped adjusting plate 35. Adjusting plate 35 is formed with a plurality of elongated slots 36 (FIG. 4). Bolts 37 extend through the elongated slots 36 and threadedly engage the supporting ledge 34 so as to secure the adjusting plate 35 to the ledge 34 at an adjusted position. A supporting plate 38 is pivotally mounted on the side of adjusting plate 35 by means of a pivot pin 39 and the supporting plate 38 is fixed to the adjusting plate 35 at an adjusted position by bolts 41 passing through arcuate slots 40. A first dressing head 45 including the bearing member 43 and the driving motor 44 for a first cup shaped working roll 42 is bolted to the supporting plate 38 so that the axis a of the working roll 42 is disposed in predetermined angular relation with the axis of the grinding wheel. The end surface of the first working roll 42 is formed with an annular dressing or working surface 42α in which are embedded diamond or other abrasive particles for dressing the first tapered outer peripheral surface 13α.

A supporting portion 46 is integrally formed at the bottom portion of slide base 23 and a letter L-shaped adjusting plate 47 is rotatably mounted on portion 46.

The adjusting plate 47 is formed with a plurality of arcuate slots 48 disposed along a circle having a center near the dressing point of a second working roll 57 to be described later so that plate 47 is fixed to an adjusted position by bolts 49. A projection 50 is formed on the rear end of adjusting plate 47, which is clamped between a pair of adjusting bolts 52α and 52b which is threadedly engaged with blocks 51α and 51b secured to the upper surface of supporting portion 46. Thus, by loosening bolts 49 and then adjusting bolts 52α and 52b it is possible to rotate adjusting plate 47 to the desired angular position so as to adjust the angle defined by the axes of the first and second working rolls 42 and 57. Furthermore, a supporting plate 53 is pivotally mounted on the side of adjusting plate 47 by means of a pivot pin 54 and the plate 53 is fixed to the adjusting plate 47 at an adjusted angular position by means of bolts 56 extending through arcuate slots 55. A second dressing head 60 including the bearing member 58 and the driving motor 59 for a cylindrical second working roll 57 is bolted to one side of supporting plate 53 so that the axis b of the working roll 57 is disposed in a predetermined angular relation with the axis of the grinding wheel 13. Diamond or another abrasive particles are embedded in the dressing or working surface 57α of the second cylindrical working roll 57 for dressing the second tapered outer peripheral surface 13b and the reentrant curved surface 13c of the grinding wheel 13.

The rotary dressing apparatus operates as follows: In order to shape the first and second tapered outer peripheral surfaces 13α and 13b which intersect with each other at a desired angle and to simultaneously work the reentrant curved surface 13c of the grinding wheel 13 the position of the supporting plate 38 is adjusted such that the axis a of the first work roll 42 becomes parallel with line X—X traversing the axis of the grinding wheel 13. Further, the position of the adjusting plate 47 is adjusted such that the axis b of the second working roll 57 is disposed in a desired angular relation with the axis of the grinding wheel 13. Concurrently therewith, the position of the supporting plate 53 is adjusted such that the outer edge 57b of the cylindrical working surface 57α of the second working roll 57 may dress the desired reentrant surface 13c of the grinding wheel 13 when moved in an upward direction. Then feed means 26 is operated to rotate feed shaft 27 for advancing feed carriage 25 by a distance equal to the degree of dressing with respect to supporting base 22 thus setting the first and second working rolls 42 and 57 to the desired cutting positions with respect to the peripheral surfaces of the grinding wheel 13.

Then, the change-over valve 61 is switched to supply oil under pressure into the lower chamber of cylinder 30 to raise the first and second working rolls 42 and 57 substantially in the vertical direction in parallel with line Y—Y passing through the axis of the grinding wheel 13. In this manner, when the lower portion of the annular working surface 42α of the first working roll 42 is positioned on line X—X, the working surface 42α thereof engages the first tapered outer peripheral surface 13a, thereby dressing the same. In the same manner, when the second working roll 57 is raised to a position close to line X—X, the cylindrical working surface 57α of the second working roll 57 engages the second tapered outer peripheral surface 13b of the grinding wheel 13 with the outer edge 57b engaged with the reentrant curved surface 13c, thus simultaneously dressing surfaces 13b and 13c. At this time, of course the grinding wheel 13 is rotated by its driving motor, not

3,747,584 shown, and the first and second working rolls 42 and 57 is rotated by their driving motors 44 and 59. In this manner, while maintaining the axis a of the first working roll 42 in parallel with line X—X, by raising the first and second working rolls 42 and 57 along line Y—Y toward the outer peripheral surfaces of the grinding wheel 13, the annular working surface 42α and the cylindrical working surface 57α of the first and second working rolls 42 and 57 are brought into contact with the first and second tapered outer peripheral surfaces 13α and 136 of the grinding wheel 13 whereby two outer peripheral surfaces 13α and 136 of the grinding wheel 13 are dressed along flat surfaces intersecting with each other at a predetermined angle (90° when the projections of axes a and b on the horizontal plane are parallel with each other) while at the same time the outer side edge of the peripheral surface 136 is dressed to have the reentrant curved configuration.

In the above described operation, when bolts 41 are loosened and the first dressing head 45 is tilted about pivot pin 39 in the clockwise direction as viewed in FIG. 3 so as to slightly incline upwardly the annular working surface 42α of the first working roll 42 from the position shown in the drawing it is possible to finish the first tapered outer peripheral surface 13α along a slightly concave curve by the annular working surface 42α by raising the slide base 23 by switching changeover valve 61.

Conversely, it is possible to finish the first tapered outer peripheral surface 13α along a slightly convex curve with the annular working surface 42α by tilting about pivot pin 39 the first dressing head 45 in the counterclockwise direction as viewed in FIG. 3 so as to slightly incline downwardly the annular working surface 42α from the position shown in the drawing.

In this manner, the first and second tapered outer peripheral surfaces 13α and 136 and the reentrant curved surface 13c of the grinding wheel 13 are dressed concurrently by the first and second working rolls 42 and 57. Where it is desired to vary the angle between peripheral surfaces 13α and 136 or the configuration of the reentrant curved surface 13c bolts 49 or 56 are loosened to tilt the second dressing head 60 carrying the second working roll 57 essentially in a horizontal or vertical plane.

As above described, in accordance with this invention, the first and second inclined outer peripheral surfaces intersecting with each other at a predetermined angle and the reentrant curved surface on the outer edge of the second outer peripheral surface of the grinding wheel can be simultaneously dressed by the cup shaped first work roll and the cylindrical second working roll which are maintained at predetermined angular positions. Furthermore, since the first and second working rolls are adjusted in a direction tangential to the periphery of the grinding wheel it is possible to maintain the cross-sectional configuration of the grinding wheel always at a definite shape irrespective of the decrease in the diameter of the grinding wheel, thus finishing the grinding wheel at high accuracies.

Furthermore, as the second roll adapted to dress the second tapered outer peripheral surface and the reentrant curved surface on the outer edge thereof is tilted for adjustment essentially in the horizontal plane it is possible to work the second tapered outer peripheral surface at different angles with the same working roll thus improving the efficiency of working. As above de6 scribed, since the cup shaped first working roll is mounted to be tiltable in the vertical direction it is possible to finish into flat, concave or convex configuration the first tapered outer peripheral surface of the grinding wheel.

Since the reentrant curved surface on the outer edge of the second tapered outer peripheral surface of the grinding wheel is formed by the second working roll, it is possible to work the curved edge of the inner race concurrehtly with the side and bottom walls thereof with the same grinding wheel. As shown in FIG. 2, the curved edge 4 smoothly merges with the side wall 2 without forming an acute edge as shown in FIG. 1 which otherwise damages the ground surfaces of another finished products.

Although the invention has been shown and described in terms of a preferred embodiment thereof, it should be understood that many changes and modifications will be obvious to one skilled in the art without departing from the true spirit and scope of the invention as defined in the appended claims.