Ball Guiding Device for an Apparatus for Lapping And/Or Grinding Balls

This application claims priority to German patent application no. 10 2024 205 849.1 filed on Jun. 24, 2024, the contents of which are fully incorporated herein by reference.

The present disclosure relates to a ball guiding device for an apparatus for lapping and/or grinding balls.

Balls can be used in various applications. Depending on the application, various requirements may be made on the geometrical properties and/or surface properties of the balls, e.g. the roundness of the ball, the surface roughness, the diameter tolerance and/or the form error of the ball, and this may be influenced, in particular, by the machining of the balls.

In order to machine the surface and/or geometry of balls, there are known apparatuses for lapping and/or grinding in which balls are machined between two concentric discs. At least one of the discs is provided with at least one ball groove, which guides the balls in the apparatus. In general, one of the discs is stationary, while the other rotates and thereby moves the balls through the at least one ball groove. The movement of the balls and/or of the disc can be used to machine the surface of the balls. For this purpose, a suitable grinding and/or lapping medium can be provided in at least one of the discs and/or the at least one ball groove, for example.

For reasons of efficient production, apparatuses for grinding or lapping balls have a plurality of ball grooves to enable several balls to be machined simultaneously. Normally, the plurality of ball grooves are arranged concentrically, and therefore they differ in diameter. However, the greater the diameter of a ball groove, the greater is the amount of material removed per revolution because the lengths of those grooves are greaer. Therefore the balls which are in the ball groove with the largest diameter undergo greater abrasion for a given number of revolutions in the apparatus than the balls that are in the ball groove with the smallest diameter.

To achieve as uniform an abrasion as possible of all the balls inserted into the apparatus and thus achieve a high geometrical and/or dimensional accuracy of all the balls machined, it is therefore advantageous to transfer the balls to different ball grooves after a predetermined time. For example, the balls in the ball groove with a smaller diameter can be transferred to the ball groove with the next-largest diameter and so on. To ensure that the ball sequence is maintained, the transfer can be performed manually, for example, but this involves a large amount of work and is very time consuming. As an alternative, transfer may be omitted, and the balls may be laboriously sorted according to size and shape after machining, and this likewise requires a large amount of time and may lead to a high rejection rate.

It is therefore an aspect of the present disclosure to provide a ball guiding device for a lapping and grinding machine for balls in which the individual balls perform the entire process of movement through the ball grooves of the discs in succession in the same sequence.

A ball guiding device for an apparatus for lapping and/or grinding balls is presented below. The apparatus has a first disc and a second disc. At least one disc has a first ball groove and a second ball groove for guiding the balls. In addition, the first disc has a recess into which the ball guiding device can be inserted. The recess can be in the form of a sector, a rectangle, an oval or the like.

The ball guiding device has at least one guide groove, which connects the first ball groove and the second ball groove of the apparatus in such a way that a ball can run through the first and the second ball groove directly in succession, wherein the at least one guide groove comprises a first ramp, which is configured to guide the ball out of the first ball groove, and a second ramp, which is configured to guide the ball into the second ball groove. In particular, the first ramp can have a positive slope, and the second ramp can have a negative slope or gradient.

In particular, the first disc can be of stationary design, and the second disc can rotate relative to the first disc. The discs can preferably be arranged one above the other in the direction of gravity, the discs thus being oriented horizontally. In particular, the first and/or second disc can be configured for grinding and/or lapping the ball.

Moreover, the first and the second ball groove can be formed both in the first and in the second disc. It is furthermore also possible for more than two ball grooves, e.g. three, four or even more than four, ball grooves to be provided in the first and/or second disc. This enables more balls to be machined simultaneously. If a plurality of ball grooves is provided, these can preferably be arranged concentrically.

The balls located between the discs can be set in motion by the rotation of one disc. As the balls roll on the surfaces of the ball groove or disc, 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, this lapping movement can play a decisive role in ensuring that the roundness error of the balls is gradually removed. Removal of the ball material means, in particular, that a ball diameter at the start of machining is larger than the ball diameter at the end of machining.

The ball guiding device has the advantage that the balls run through the ball grooves in succession in the same sequence without having to be transferred manually from one ball groove to the other.

The balls can be formed from metal, glass, wood, plastic, ceramics or a combination thereof, for example.

The at least one guide groove can comprise a first side element, a second side element and/or a bottom element, for example. The provision of side elements can improve lateral guidance of the balls in the ball guiding device.

In a case in which the apparatus has more than two ball grooves, the ball guiding device can preferably also be provided with a plurality of guide grooves. In particular, one guide groove can be provided for each additional ball groove provided in addition to the first and second ball groove. This makes it possible for the balls to run through all the ball grooves in succession in the same sequence without having to be transferred manually.

Furthermore, the first ramp can have a first ramp slope and a first ramp length, and the second ramp can have a second ramp slope and a second ramp length. Moreover, the first ramp slope can be equal to or different from the second ramp slope.

In addition or as an alternative, the first ramp length can be equal to or different from the second ramp length. This enables the balls to be guided into and/or out of the corresponding ball groove in such a way, for example, that a probability that the balls will come into contact and/or be damaged is reduced.

Furthermore, the ball guiding device can be supported in a free-floating manner on at least one of the discs of the apparatus. This enables the ball guiding device to adapt to any irregularities in the discs and/or the ball grooves.

The ball guiding device can preferably have at least one level intermediate section, which connects the first and the second ramp. This enables the balls to be transferred from the first to the second ball groove by the ball guiding device in a manner which is as uniform as possible.

Furthermore, the first and/or the second ramp can be formed on a bottom of the guide groove. For example, the provision of the ramp on the bottom of the guide groove enables the ball to be directly raised and thus guided out of the first ball groove and/or into the second ball groove.

However, it is also possible for the ball to be guided indirectly out of the first ball groove and/or into the second ball groove. For example, it is possible to provide a spacer, which is arranged around a ball and is configured to space apart two adjacent balls. For example, the provision of the ramp on the side of the guide groove enables the ball to be raised indirectly by raising the spacer. This can have the advantage of making it possible to ensure that a spacer arranged around a ball is taken along during the transfer from the first to the second ball groove.

The guide groove can preferably have at least one side wall, which is configured as a guide element for a spacer that is suitable for spacing apart two adjacent balls. The guide element can advantageously ensure that the spacer is not lost as it runs through the apparatus and that the balls do not come into contact.

In particular, the at least one side wall can have a first ramp, which is configured to guide the spacer out of the first ball groove, and/or can have a second ramp, which is configured to guide the spacer into the second ball groove. This can have the advantage of making it possible to ensure that a spacer arranged around a ball is taken along during the transfer from the first to the second ball groove.

For example, the at least one guide groove can have a bottom and at least one side wall, and the first ramp can be arranged on the bottom, and the at least one side wall can have a further ramp, which is configured to guide the spacer out of the first ball groove.

Furthermore, the further ramp can have a third ramp slope and a third ramp length, wherein the first ramp slope is equal to or different from the third ramp slope. This enables the balls to be guided into and/or out of the corresponding ball groove in such a way, for example, that a probability that the balls will come into contact and/or be damaged is reduced.

In addition or as an alternative, the first ramp length can be equal to or different from the third ramp length. This enables the balls to be guided into and/or out of the corresponding ball groove in such a way, for example, that a probability that the balls will come into contact and/or be damaged is reduced.

When viewed in the direction of circulation of the balls, the further ramp can preferably be configured to guide the spacer out of the first ball groove ahead of the ball. In other words, the ball can be guided out of the first ball groove with the aid of the spacer. For example, the spacer can be designed in such a way that, when the ball runs in the ball groove, the ball rotates freely in the spacer but can nevertheless be raised with the aid of the spacer. Since the ball can be guided out of the first ball groove with the aid of the spacer, it is advantageously possible to ensure that the spacer remains arranged around the ball. This makes it possible to avoid a collision between two balls, which might damage the balls.

Furthermore, the at least one side wall can comprise a fourth ramp, which is configured to guide the spacer into the second ball groove.

In particular, a profile of the first, second and/or further ramp can be linear or non-linear.

The ball guiding device can furthermore preferably have a return section, which is configured to guide the balls back from the second groove to the first groove, wherein the return section has a return groove, which runs at least partially via the ball guiding device. This enables the balls to be guided through all the ball grooves of the apparatus. For example, the balls can run through the ball grooves of the apparatus successively from the inside outwards and then subsequently be conveyed back to the innermost ball groove by the return section.

Furthermore, the ball guiding device can have at least one bearing element, which is configured to support the ball guiding device on one of the discs of the apparatus for lapping and/or grinding balls. The at least one bearing element can furthermore also be configured to enable a relative movement between the ball guiding device and the rotating disc of the apparatus. The at least one bearing element can be a sliding element, a roller, a ball, and/or a bearing, in particular a rolling bearing, for example. It is thereby advantageously possible to achieve support for the ball guiding device on the disc in a manner which involves as little friction as possible.

As a preferred possibility, a plurality of bearing elements may also be provided. In this case, the plurality of bearing elements may be of the same type and/or of different types. For example, the ball guiding device can be fitted with a plurality of bearings and rollers.

Furthermore, the ball guiding device can have at least one holding element, which is configured to hold the ball guiding device in the apparatus. The holding element may be, in particular, an overhanging holding nose or an overhanging projection, which is configured to interact with a guide slot provided in the disc in order to hold the ball guiding device in position.

A further aspect of the disclosure comprises a ball guiding device configured for use with an apparatus for lapping and/or grinding balls. The apparatus includes a first disc and a second disc, and the second disc has a first continuous groove and a second continuous groove for guiding the balls and a first wall separating the first continuous groove from the second continuous groove. The first disc has a recess exposing the first continuous groove and the second continuous groove. The ball guiding device comprises a body having a first guide groove having a first end insertable through the recess into the first continuous groove and a second end insertable through the recess into the second continuous groove and a raised central portion connecting the first end of the first guide groove to the second end of the first guide groove and configured to overlie the first wall. The first guide groove includes a first ramp extending from the first end of the first guide groove to the raised central portion of the first guide groove and configured to guide the balls out of the first continuous groove and a second ramp extending from the raised central portion of the first guide groove to the second end of the first guide groove and configured to guide the balls into the second continuous groove.

Further advantages and advantageous embodiments are indicated in the description, the drawings and the claims. In this context, the combinations of features indicated in the description and in the drawings are, in particular, purely illustrative, and therefore the features may also be present individually or in different combinations.

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.

A ball guiding devicefor an apparatusfor lapping and/or grinding ballsis described with reference to. In particular, the ballscan be ceramic balls. For the sake of clarity, just one ball is illustrated. However, the apparatusis configured to machine several balls simultaneously. In particular, the number of balls accommodated in each ball groove can correspond to complete filling of the smallest-diameter ball groove.

The apparatushas a first discand a second disc, wherein the second discis of stationary design and the first discrotates relative to the second disc. As can be seen in, the discs,are arranged one above the other, the discs thus being oriented horizontally.

The discs,each have three concentrically arranged ball grooves(continuous grooves) in which the ballsare accommodated during the machining process. The balls located in the ball groovesbetween the discs,can be set in motion by the rotation of one disc. As the ballsroll on the surfaces of the ball grooveor discs,, 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 ball groovestogether with the balls, this lapping movement can play a decisive role in ensuring that the roundness error of the ballsis gradually removed and/or that damage to the ball surface is reduced or even avoided.

In addition, the first dischas a recess, into which the ball guiding deviceis inserted. The recesscan be in the form of a sector, a rectangle, an oval or the like. The ball guiding devicehas a base plate, in which a first guide groove, which connects the first ball groove and the second ball groove of the apparatusin such a way that a ball can run through the first and the second ball groove directly in succession, and a second guide groove, which connects the second ball groove and the third ball groove of the apparatusin such a way that a ball can run through the second and the third ball groove directly in succession, are formed.

The guide grooves,each comprise a first side element, a second side elementand a bottom element. The bottom elementcan be formed by the base plate, for example. Furthermore, the first and the second side element,can be formed by a side wall. In particular, the side wallcan separate the first guide groovefrom the second guide groove, the side wall thus serving as a side element,both for the first guide grooveand the second guide groove.

In order to guide the balls out of the corresponding ball groove, the guide grooves,comprise, at their beginning when viewed in the direction of circulation, a first ramp, which is configured to guide the ballsout of the ball groove. At their end when viewed in the direction of circulation, the guide grooves,likewise comprise a second ramp, which is configured to guide the ballinto the adjacent ball groove. As can be seen in, the ramps,are formed on the bottom element. A level intermediate section, which connects the first and the second ramp,, is provided between the ramps,in each guide groove,.

Finally, the ball guiding devicealso has a return section, which connects the third ball groove to the first ball groove, thus ensuring that the ballsare guided back to the first guide groove again after passing through the third guide groove. The return sectionlikewise has a first rampwhich guides the ball out of the third ball groove. The return sectionhas a return groovewhich has a sectionwith a slope which conveys the ballsupwards. The return groovethen runs at least partially via the guide grooves of the ball guiding device. In order to guide the balls back into the first ball groove, the return groovehas a further section, which has a gradient via which the balls are guided back into the first ball groove. Together with the return section, the ball guiding deviceenables the ballsto run several times through all the ball grooves in succession in the same sequence.

Furthermore, at least some of the ballscan be mounted in a spacer, which ensures that two balls do not come into direct contact. Particularly in the case of ceramic balls, it may be necessary to prevent two balls from colliding directly in order to avoid damage to the balls. In the case where the ballshave a spacer, which is arranged around the balland is designed in such a way that the ball accommodated in the spaceris raised with the spacerwhen the spaceris raised, a guide elementfor a spaceris furthermore formed on the side elements,. The guide elementcan advantageously ensure that the spacer is not lost as it runs through the apparatus and that the balls do not come into contact. In order to form the guide element, a recessof U-shaped cross section, in which the spacercan be guided, is formed in the side elements,.

In order to reliably take along the spacerwhen the ballis transferred from one ball groove to the other ball grooves, the guide elementcan also be provided with a first and a second ramp,, thus enabling the spacerto be guided out of the first ball groove and guided into the second ball groove.

Advantageously, when viewed in the direction of circulation of the balls, the ramps,for the spacerare designed in such a way that the spaceris guided out of the ball groove ahead of the ball. For example, the spacercan be designed in such a way that, when the ballruns in the ball groove, the ballrotates freely in the spacerbut can nevertheless be raised with the aid of the spacer. After the spacerhas been raised by the ramp, together with the ball, the ballitself can then be raised with the aid of the rampuntil it is once again freely rotatable in the spacer.

When it is introduced into the adjacent ball groove, the process can take place in reverse. That is to say that, first of all, the rampcan lower the balluntil the ball is held in the spacer. The spacer, together with the ball, is then guided via the rampinto the second ball groove, while the ramplowers the spaceruntil the ballis once again freely rotatable in the spacerwhen it is being guided in the ball groove.

Each ramp,,,has a respective ramp slope, a respective ramp length and a respective ramp profile. The slope of the first and second ramp,can be equal or different. The length of the first and second ramp,can likewise be equal or different. The profile of the first and the second ramp,can be linear or, alternatively, non-linear, e.g. exponential. Furthermore, the slope of the ramps,can be equal or different. The length of the ramps,can likewise be equal or different. The profile of the ramps,can be linear or, alternatively, non-linear, e.g. exponential. The ramps,for the spacercan preferably have a different slope, a different length and/or a different profile in comparison with the first and second ramp,.

The ball guiding deviceis mounted in a free-floating manner on the discof the apparatus, enabling it to adapt to any irregularities in the discand/or the ball grooves. For this purpose, the ball guiding device is supported on the discby means of a plurality of rolling bearings. Furthermore, a plurality of rollersis also arranged on an underside of the base plateof the ball guiding device, and these improve sliding of the ball guiding deviceon the rotating disc.