SPACER FOR SPACING APART BALLS IN AN APPARATUS FOR LAPPING AND/OR GRINDING BALLS AND APPARATUS FOR LAPPING AND/OR GRINDING BALLS

Abstract

An apparatus for lapping and/or grinding balls includes at least one disc having at least one encircling ball groove configured to receive and guide a plurality of balls, and a plurality of spacers each having a pocket configured to receive a respective one of the plurality of balls. Each of the pockets has a first region having a first diameter and a second region having a second diameter smaller than the first diameter.

Claims

1. An apparatus for lapping and/or grinding balls comprising: at least one disc having at least one encircling ball groove configured to receive and guide a plurality of balls, and a plurality of spacers each having a pocket configured to receive a respective one of the plurality of balls, wherein each of the pockets has a first region having a first diameter and a second region having a second diameter smaller than the first diameter.

2. The apparatus according to claim 1, wherein each of the pockets is conical.

3. The apparatus according to claim 2, wherein an outer surface of each of the plurality of spacers is cylindrical.

4. The apparatus according to claim 3, including a guide element for guiding the spacer.

5. The apparatus according to claim 4, wherein the guide element has a U-shaped profile.

6. A system comprising: an apparatus according to claim 1, and the plurality of balls, wherein the first diameter of the pocket is based on a starting size of the balls and the second diameter of the pocket is based on a final size of the balls.

7. The system according to claim 6, wherein the apparatus and the balls are configured so that each of the plurality of balls is freely rotatable in a respective one of the plurality of pockets.

8. The system according to claim 7, wherein a thickness of the spacer is based on an angle of contact of the balls in the at least one ball groove.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 is a schematic cross-sectional view through an apparatus for lapping and/or grinding balls, which apparatus includes a spacer, according to a first embodiment of the present disclosure.

[0029] FIG. 2 is a schematic cross-sectional view through an apparatus for lapping and/or grinding balls, which apparatus includes a spacer, according to a second embodiment of the present disclosure.

[0030] FIG. 3 is a perspective view of the spacer of FIG. 1.

[0031] FIG. 4 is a bottom plan view the spacer of FIG. 3.

[0032] FIG. 5 is a sectional elevation view taken along the line A-A in FIG. 4.

DETAILED DESCRIPTION

[0033] The disclosure will be explained in greater detail below with reference to exemplary embodiments illustrated in the drawings. Here, the exemplary embodiments and the combinations shown in the exemplary embodiments are purely illustrative and are not intended to define the scope of protection of the disclosure. This is defined solely by the appended claims. In the text which follows, elements that are identical or functionally equivalent are denoted by the same reference signs.

[0034] FIG. 1 shows a schematic cross-sectional view through an apparatus 1 for lapping and/or grinding balls 2 according to a first embodiment. The apparatus 1 has a first disc 4 and a second disc 6. At least one encircling ball groove 8 is formed in the first disk 4 and at least one encircling ball groove 10 is formed in the second disc 6. It is also possible for each of the discs to be provided with more than one ball groove 8, 10, e.g. two, three, four or more. Of course, it is also possible for just one of the two discs 4, 6 to be provided with one or more ball grooves 8, 10. If a plurality of ball grooves 8, 10 is provided, these can preferably be arranged concentrically.

[0035] As can be seen in FIG. 1, the two discs 4, 6 are arranged horizontally one above the other, and the second disc 6 is configured to remain stationary during use while the first disc 4 rotates relative to the second disc 6. The balls 2 located between the discs 4, 6 can be set in motion by the rotation of the one disc 4. As the balls roll on the surfaces of the ball grooves 8, 10 or discs 4, 6, a sliding movement of greater or lesser magnitude may occur, this being referred to as the lapping movement. In combination with appropriate lapping media, which can be inserted into the apparatus together with the balls 2, this lapping movement can play a decisive role in ensuring that the roundness error of the balls 2 is gradually removed.

[0036] For inserting and removing the balls 2 into and from the apparatus 1, it is possible, in particular, for the second disc 6 to be provided with a recess (not shown).

[0037] As already described above, the balls 2 are set in motion by the relative rotation of the discs 4, 6, and therefore there is also a risk that the balls 2 will come into contact with adjacent balls 2 in the apparatus. To prevent the balls 2 coming into direct contact with each other, a spacer 12 is furthermore provided.

[0038] The spacer 12 (see FIGS. 3 to 5) has a main body 14 with a through-pocket 16 in which an individual one of the balls 2 can be accommodated. The outer lateral surface of the main body 14 has a cylindrical shape. The pocket 16 has a first diameter D1 and a second diameter D2, wherein the first diameter D1 is larger than the second diameter D2. In this case, the pocket 16 is preferably conical. To prevent a ball 2 from being damaged in the case of contact with the spacer 12, the spacer 12 is preferably produced from a plastic.

[0039] The spacer 12 is arranged in the apparatus 1 in such a way that the second, smaller, diameter D2 is at the bottom (relative to the direction of gravity). By virtue of the fact that the pocket 16 has a first, larger, diameter D1 and a second, smaller, diameter D2 and the smaller of the two diameters D1 is arranged at the bottom, it is not so easy for the spacer 12 to become detached from the ball 2 since it remains caught on the ball 2, or the ball 2 is held by the spacer 12. It furthermore makes it possible for the ball 2 to be raised together with the spacer 12.

[0040] The first, larger diameter D1 of the pocket 16 of the spacer 12 is chosen in accordance with an initial size of the ball 2, wherein D1 is larger than the diameter of the ball at the start of machining. Furthermore, the second, smaller, diameter D2 of the pocket 16 is smaller than the diameter of the ball 2 at the end of machining. This makes it possible to prevent the ball from dropping through the spacer since, during grinding and/or lapping of the ball 2, the diameter may decrease in the course of machining. In addition, the second, smaller, diameter D2 of the pocket 16 may nevertheless be chosen to be so large that the ball 2 can come into contact with the ball groove 8 without resting against the spacer 12.

[0041] In FIG. 1, the spacer 12 is being guided between the discs 4, 6 during the operation of the apparatus 1 with the spacer 12 resting partially on the lower disc 4. By virtue of the fact that the spacer 12 is resting on the lower disc 4, the spacer 12 can be held at a specified distance or a specified position with respect to the ball groove 10 in the lower disc 4. That is to say that the disc 4 also serves as a guide element for the spacer 12.

[0042] A distance between a zone of support 18 of the ball 2 in the ball groove 8 and a point of support of the spacer 12 on the disc 4 is selected in such a way that the ball 2 is freely rotatable in the spacer 12. That is to say that, when the ball 2 is accommodated in the ball groove 8 or when it is running in the ball groove 8, it has substantially no contact with the spacer 12. By virtue of the ability of the ball 2 to rotate freely in the spacer 12, grinding and/or lapping of the ball 2 can be performed more uniformly. The zone of support 18 of the ball 2 in the ball groove 8 is dependent on the diameter of the ball 2 and accordingly changes during the machining of the ball 2 in the apparatus 1 since the diameter of the ball 2 is reduced during machining by the removal of material.

[0043] In FIG. 1, the thickness 20 of the spacer 12 is adapted to a size of an angle of contact of the ball grooves 8, 10 of the apparatus 1, wherein the total angle of contact is composed of the angle of contact 22-1 of the ball groove 10 formed in the upper disc 6 and the angle of contact 22-2 of the ball groove 8 formed in the lower disc 4. In particular, the angle of contact can indicate in angular degrees and/or in percent the contact region in which the ball groove or ball grooves 8, 10 surrounds or surround the ball 2.

[0044] In FIG. 1, the thickness 20 of the spacer 12 is chosen so that the spacer 12 almost fills the region in which the ball 2 is not surrounded by the ball grooves 8, 10. Depending on the apparatus, the contact region of the ball grooves with the ball can be between 25% and 95%, preferably between 30% and 90%, and the angle of contact can be between 100 and 330.

[0045] FIG. 2 shows a schematic cross-sectional view through an apparatus 1 for lapping and/or grinding balls 2 according to a second embodiment. The apparatus 1 in FIG. 2 differs from the apparatus 1 in FIG. 1 in that it has a guide element 24 for guiding the spacer 12. For example, the guide element 24 can be designed to hold the spacer 12 at a specified distance and/or a specified position with respect to the ball groove 8, 10. In particular, the guide element 24 can be arranged in such a way that the ball is freely rotatable in the spacer. In FIG. 2, the guide element 24 is designed as a U-shaped profile with a first limb 26, a second limb 28 and a central limb 30, wherein the distance between the two limbs 26, 28 can be adapted in such a way that the spacer 12 can be guided between the two limbs 26, 28.

[0046] In summary, it is possible to provide an apparatus 1 for grinding and/or lapping balls 2 with which the risk of the balls 2 coming into contact with one another in the apparatus 1 is significantly reduced. In particular, the apparatus 1 can be suitable for ceramic balls 2 since ceramic balls have a higher risk of being damaged in the event they collide with one another.

[0047] Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Furthermore, each of the additional features and teachings disclosed above may be utilized separately or in conjunction with other features and teachings to provide improved ball spacers for lapping and/or grinding balls and apparatuses for lapping and/or grinding balls including such spacers.

[0048] Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

[0049] All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

LIST OF REFERENCE SIGNS

[0050] 1 apparatus [0051] 2 ball [0052] 4 lower disc [0053] 6 upper disc [0054] 8 lower ball groove [0055] 10 upper ball groove [0056] 12 spacer [0057] 14 main body [0058] 16 pocket [0059] 18 zone of support [0060] 20 thickness [0061] 22-1 angle of contact, top [0062] 22-2 angle of contact, bottom [0063] 24 guide element [0064] 26 upper limb [0065] 28 lower limb [0066] 30 central limb [0067] D1 first diameter [0068] D2 second diameter