Concept for a ball guide channel of a ball-bearing linear guide

Abstract

A ball guide channel (30; 31; 32; 51) for a guide carriage (12; 50) of a ball-bearing linear guide which can be arranged linearly movable on a guide rail (11), wherein a ball feed channel (31) and a ball return channel (32) of the ball guide channel (30; 31; 32; 51) are each at least partially bounded by a circumferential surface (38), and wherein the ball guide channel (30; 31; 32; 51) is designed such that for a ball (17) circulating in the ball guide channel (30; 31; 32; 51) at least three predefined contact surfaces (36; 37; 38) spaced apart from each other in the circumferential direction are provided.47) are provided, on which the ball (17) can roll, so that at least three-point contact is maintained between the ball (17) and the lateral surface of the ball feed channel (31) and the ball return channel (32) in an unloaded state, and the ball (17) in a loaded state can roll in the ball feed channel (31) only between the guide rail (11) and a contact surface (36-3) of the ball feed channel (31), wherein the lateral surface has projecting and recessed lateral surface sections (46; 48) in a radial direction perpendicular to the circumferential direction (38) and pointing towards an interior of the ball guide channel (30; 31; 32; 51), wherein the contact surfaces (36; 37; 47) are formed at least partially by projecting lateral surface sections spaced apart from each other in the circumferential direction (38).

Description

[0001] Exemplary embodiments of the present invention relate to linear guides and, in particular, ball channels of guide carriages for such linear guides.

[0002] A linear guide is generally understood to be an arrangement that enables the frictionless translation of one or more moving components of a machine while simultaneously ensuring that the direction of movement is maintained along a linear path. Linear guides can be broadly categorized according to their bearing type into sliding guides and rolling guides. Rolling guides are based on the principle of rolling elements rotating between two guide elements moving relative to each other. As with rotary bearings, the rolling elements can be, for example, balls, rollers, needles, or other rolling components. Examples of rolling guides include profile rail guides and linear ball bearings, which can also be referred to as ball bushings. Linear guides are not limited to exclusively linear movements.Rather, they enable translational movement compared to rotational movements, which are guided by corresponding rotary bearings. Especially in the field of linear bearings, the terms "linear" and "translational" are therefore often used synonymously.

[0003] Linear guides enable precise translational movements in a wide variety of applications. A linear guide generally comprises a guide rail, such as a shaft or profile rail, and a linear or guide carriage, which, according to some embodiments, particularly with linear ball bearings, can also be designed as a bushing and is arranged to move linearly along the guide rail. Especially in applications where the amplitude of the linear movement is on the order of the outer dimensions of the guide carriage and parallel to the direction of movement, or even exceeds it, so-called recirculating ball guides are frequently used. A recirculating ball guide is characterized by the fact that the guide carriage is mounted to move relative to the guide rail by means of balls, and that the balls circulate on a closed, i.e., virtually endless, track.A ball screw guide thus allows any linear movement of the guide carriage relative to the guide rail, which is limited only by the dimensions of the guide rail and, if necessary, by an installation environment.

[0004] In so-called profile rail guides, the guide carriage, which in this context can also be referred to as a running carriage, has a generally U-shaped cross-section that engages a profiled guide or profile rail. The guide carriage is mounted on the guide rail by means of rolling elements. In other words, the guide carriage forms an outer guide section of the linear guide, and the guide rail forms an inner guide section of the profile rail guide, with the inner and outer guide sections mutually supporting each other via rolling elements.

[0005] In linear ball bearings, also known as ball bushings, a guide carriage or cage, typically designed as a bushing and with a substantially cylindrical cross-section, surrounds a shaft, especially a round one, which acts as a guide rail. This is why this particular form of linear guide can also be called a shaft guide. The bushing is mounted on the shaft in a rolling bearing configuration, thus forming an outer guide element of the linear ball bearing, while the shaft forms an inner guide element.

[0006] The Fig. Figure 1 shows a perspective view of a conventional linear guide designed as a linear ball bearing 10 for illustration purposes.

[0007] The conventional linear guide 10 comprises a shaft 11 as an inner guide element, and a bushing 12 cylindrically surrounding the shaft 11, which is hereinafter also referred to as a cage. The bushing or cage 12 in turn comprises a plurality of endless ball recirculations 13. An endless ball recirculation 13 is formed by a ball channel, which can be divided into a feed or load / support channel and a return channel. In the feed or support channel, there is a momentarily load-bearing row of balls, i.e., those balls 17 that support the bushing 12 against the shaft 11. The balls 17 in the feed channel roll between a raceway formed by the shaft surface and a counter-race 14 located on the side of the bushing 12. Via deflection sections 15, which are located according to Fig. In the bearing arrangement 10 shown in Figure 1, the balls 17 are housed in end rings 16. From the feed channel, they can be deflected into a corresponding unloaded return channel, and vice versa. This creates a continuous ball circulation in the ball guide channel 13. The bearing arrangement 10 can be sealed against the external environment by means of seals 19 located on the end rings 16. Lubricant reservoirs can be located in the deflection elements or end rings 16 for the lubrication of the rolling elements 17.

[0008] The Fig. Figure 2a shows the linear guide arrangement 10 of the Fig. 1 in a cross-sectional view.

[0009] In the cross-sectional view of the Fig. Figure 2a shows a total of six ball guide channels 20-1 to 20-6, which can be further subdivided into lead or support channels 21 and return channels 22. In the lead or support channels 21, the rolling elements or balls 17 roll between raceways 23, formed by the surface of the shaft 11, and counter-raceways 24. The counter-raceways 24 are formed by counter-raceway sections 14 fitted into the bushing or cage 12, which can, for example, be made of hardened steel. The rolling elements 17 guided in the lead channel 21 are guided by means of the Fig. The deflection areas 15 described in 1 are deflected into a corresponding return channel 22 by being returned unloaded, in order to then enter the supply channel 21 again.

[0010] According to the Fig. 1 and Fig. In the linear guide arrangement 10 shown in Figure 2, the ball guide channels 20-1 to 20-6, comprising the ball feed and ball return channels 21, 22, are each round in cross-section perpendicular to the shaft axis. In other words, the ball guide channels 21, 22 each have a cylindrical shape.

[0011] The Fig. Figure 2b shows an enlarged view of a ball feed channel 21 in which a ball 17 rolls in a defined manner between the shaft 11 and the counter-track 24 formed by the counter-track section 14. There are three defined contact points 26-1, 26-2 and 26-3: between the ball 17 and the shaft 11 (contact point 26-1), between the ball 17 and an adjacent ball (contact point 26-2), and between the ball 17 and the counter-track 24 (contact point 26-3).

[0012] While the position of the balls 17 in the feed channel 21 is defined by the shaft 11 or the raceway 23 and the counter-raceway 24 in the conventional round cross-section of the ball guide channels 21, 22, the position of a ball 17 in the return channel 22 is not uniquely defined in the conventional round cross-section of the ball guide channel, as can be seen in the enlarged view of the Fig. 2c is illustrated.

[0013] The Fig. Figure 2c shows three adjacent spheres 17-1, 17-2, and 17-3 in a circular return channel 22. This illustration clearly shows that there is no (pre-)defined contact point between the spheres 17 and the surface of the return channel 22. A contact point 27 between the first sphere 17-1 and the surface of the return channel 22 is shown only as an example. The other spheres 17-2 and 17-3, located behind the first sphere 17-1, each have different contact points or lines on the surface or cage wall, respectively.

[0014] The conventional round ball guide channel geometry described above has several disadvantages. If the diameter or cross-section of the ball guide channels 21, 22 is too narrow, there is a risk of increased friction between a ball 17 and the cage wall due to tight contact. Conversely, if the cross-section or diameter of the ball guide channels 21 and especially 22 is too wide, this can lead to increased and unpleasant noise. Based on the Fig. 2c explained undefined positions of the balls in the return channel 22 can lead to an increase in friction between adjacent balls.

[0015] Another problem with a conventional round channel cross-section can arise during the manufacturing of the bushing or cage 12. The cage 12 is typically manufactured using an injection molding process. Due to the conventional round geometry of the ball channels 20-1 to 20-6, so-called "floating" can occur during the injection molding process, particularly in a transition area from the feed channel 21 to the shaft 11, i.e., on the inner circumference of the cage 12 in the area of ​​the ball feed channels 21. Correcting the injection mold with regard to such quality problems is often difficult, as the radial slides, which form the cavities for the ball recirculations as well as the passage for the shaft, must be perfectly aligned at this point. This problem is further complicated by the fact that a draft angle on the axial core, i.e., at the axial shaft passage, is hardly feasible for technical and aesthetic reasons.

[0016] DE 36 15 899 A1 relates to a rolling element guide arrangement in which the movement of balls in a load-bearing section of an endless circulation path between inner and outer guide grooves is guided by guide tongues and side guides.

[0017] US Patent 6,550,969 B1 discloses a sleeve whose internal interface has several recesses between circular segments on which rolling elements roll.

[0018] From DE 10 2011 017 756 A1 a guide carriage of a rolling bearing linear guide is known, in which rolling elements are guided on a curved path around a stiffness-increasing arrangement of the guide carriage.

[0019] DE 20 2012 101 437 U1 discloses a raceway surface for a ball rolling between the raceway surface and a wave surface. The raceway surface has a polygonal, in particular partially polygonal, cross-section in a plane perpendicular to the extent of the raceway.

[0020] US 5,755,516 A describes a rolling element circulation passage in a slide that is movable along a guide rail. A section of the rolling element circulation passage runs between two opposing surfaces of the slide, into which rolling element grooves are formed, and the guide rail.

[0021] Against this background, one object of the present invention is to provide an improved concept for ball guide channels for ball-bearing linear guides.

[0022] The problem is solved by a ball guide channel for a guide carriage of a ball-bearing linear guide which can be arranged linearly on a guide rail and has the features of claim 1.

[0023] A fundamental concept of the present invention is to provide the cross-section of the ball guide channel with a geometry other than the conventional round one. Instead of exposing the balls, particularly in the ball return or recirculation channel, to locally undefined contact surfaces, the present invention proposes to design a ball guide channel such that, for a ball guided or circulating in the ball guide channel, at least three predefined contact surfaces are provided, spaced apart from one another in the circumferential direction of the outer surface of the ball guide channel, on which the ball can roll. In other words, a geometric shape is provided for the ball guide channel such that at least three-point contact is maintained between the ball and the channel or cage wall.

[0024] By means of at least three predefined contact surfaces molded into the outer surface of the ball guide channel, axial displacement or guidance of the rolling elements or balls within the ball guide channel can be defined more precisely than with conventional round cross-sections. According to exemplary embodiments of the present invention, dimensional control is only required at the predefined contact or guide surfaces or guide lines. This enables smoother running, reduced friction, and noise reduction in ball-bearing linear guides.

[0025] To provide at least three predefined contact surfaces spaced apart circumferentially in the ball guide channel, its outer surface, according to the invention, has projecting and recessed sections in a radial direction perpendicular to the circumferential direction of the outer surface and pointing towards the interior of the ball guide channel. The at least three predefined contact surfaces or contact surface sections are at least partially formed by the projecting and circumferentially spaced outer surface sections. The ball guide channel can be a forward channel, but in particular a return channel.

[0026] Exemplary embodiments of the present invention include various ball guide channel geometries, which provide projecting and recessed sections of the outer surface. According to some embodiments, the ball guide channel can have a polygonal cross-section, such as a polygonal cross-section, in a plane perpendicular to an axial extension of the linear guide or the ball guide channel. This means that, according to these embodiments, the ball guide channel is not round, but, for example, pentagonal, hexagonal, or more polygonal. According to other embodiments, the ball guide channel can have a substantially round cross-section in a plane perpendicular to the axial extension of the ball guide channel, with radially inwardly projecting protrusions arranged at predefined intervals along the outer surface in the circumferential direction and serving as contact surfaces.In such embodiments, the protruding sections of the outer surface, i.e., the projections which serve as contact surfaces, are, for example, convex, whereas the remaining recessed sections of the outer surface are cylindrical or concave.

[0027] The ball guide channel can be either a forward or a return channel. In a (ball guide) forward or support channel, a surface of the guide rail or shaft forms a raceway for endlessly rotating balls guided in the forward channel. The guide carriage or bushing includes a counter-raceway for the endlessly rotating balls. The forward channel is designed such that, in the absence of a shaft (i.e., in the unloaded state), at least two radially inwardly projecting and circumferentially spaced sections of the forward channel's outer surface, together with the counter-raceway, serve as contact surfaces for a ball guided in the forward channel. This means that at least two contact or guide surfaces are formed by a bushing or cage designed as an injection-molded part, while a further contact or guide surface is formed by the counter-raceway molded into the bushing or guide carriage.A guide surface is formed for the rotating (and unloaded) balls. Under load, the balls roll between the raceway on the shaft and the counter-raceway in the bushing. There is no contact between the loaded ball and the two contact or guide surfaces of the bushing. In fact, under load, i.e., with the shaft in place, additional contact between the loaded ball in the feed channel and the two contact or guide surfaces of the cage is undesirable.

[0028] A ball return channel can be designed, according to exemplary embodiments, such that at least three radially inwardly projecting and circumferentially spaced sections of the ball return channel's outer surface serve as contact surfaces for a ball returned in the channel during operation of the linear guide. Since there are no dedicated running or counter-running surfaces in a ball return channel as in a feed channel, at least three predefined contact areas for guiding the balls are located along the circumference of the return channel's outer surface.

[0029] According to exemplary embodiments, the contact surfaces or contact points can be arranged along the circumference of the cylindrical surface of the ball guide channel such that surface normals through the contact points between a rotating ball and the at least three predefined contact surfaces intersect at a point in the cross-sectional plane that essentially corresponds to the center point of the ball guided in the ball guide channel. This results in a symmetrical arrangement of the contact points between the ball and the cylindrical surface of the ball guide channel, which in particular ensures smooth running and thus reduces noise.

[0030] Radially recessed sections of the ball guide channel's outer surface, which do not serve as one of the predefined contact surfaces for a ball guided in the channel during operation of the linear guide, can, according to exemplary embodiments, be provided with draft angles to facilitate the removal of a cage or guide carriage (e.g., bushing) manufactured by injection molding from an injection mold. Additionally or alternatively, a lubricant reservoir can be formed between at least one recessed section of the ball guide channel, which does not serve as a contact surface for a ball guided in the channel during operation of the linear guide, and a ball guided in the channel.This means that cavities in the ball guide channel that do not serve to guide the balls and may have draft angles can also be used as lubricant reservoirs. "Offset cavities" in the guide channel essentially create a lubricant reservoir automatically. The lubricant (e.g., grease) will accumulate there after initial lubrication or relubrication and be released to the rotating balls during operation. The draft angles that can be applied to these surfaces to facilitate the injection molding process do not affect the function of the lubricant reservoir.

[0031] According to a further aspect of the present invention, a guide carriage for a ball-bearing linear guide is also provided, wherein the guide carriage, such as a profile rail carriage or a cylindrical ball bushing / cage, has at least one ball guide channel according to the invention for endlessly rotating rolling elements, such as balls. Likewise, embodiments of the present invention naturally also provide a linear guide with a guide rail and a guide carriage, wherein the guide carriage is mounted on the guide rail by means of a ball guide channel according to the invention.

[0032] The inventive design of the ball guide channel allows the bushing or cage to be made more stable in the area of ​​the pocket opening, i.e., in the transition area from the cage to the shaft, where the lead-in channel is open, thus making it more difficult for the balls to unintentionally fall out during improper handling, transport, or assembly. According to embodiments of the present invention, the radial cross-section of axially extending retaining webs for the balls in this transition area can be made stiffer than in the case of a conventional round ball guide channel.

[0033] The cross-sectional contour according to the invention allows the rolling path of the balls guided in the ball guide channel to be shifted further inwards from a circumferentially (tangentially) pointing tip of the axial retaining webs. This, in turn, prevents the formation of a web layer between the shaft bore and radial injection mold slides during the manufacturing of the guide carriage or bushing, thus reducing the likelihood of malfunctions in the linear bearing. Tool correction can therefore be avoided.

[0034] In embodiments of the present invention, draft angles can be integrated into the guide carriage, particularly in the area of ​​the ball guide channels, which are visually inconspicuous and do not cause any technical problems. It is also possible to integrate draft angles into the ball channel on several recessed sections of the cylindrical surface, thereby making the injection mold more robust or optimizing the cooling system of the injection mold.

[0035] According to exemplary embodiments of the present invention, the balls in the ball guide channel are preferably guided by a three-point contact. This three-point contact allows for better definition of the axial displacement of the balls, i.e., in the axial extension direction of the guide carriage or the ball guide channel, than with conventional linear guides. This results in smoother running, reduced friction of the entire ball circulation, and noise reduction. Furthermore, the defined three-point contact of the ball in the ball guide channel simplifies the design and manufacturing optimization of the connection between the guide carriage or the bushing and an axially adjacent component, such as a deflection section. The cavity formed by a ball guide channel according to the invention can also be used as a holder or orientation geometry for a ball chain.

[0036] Some embodiments of the present invention will now be explained in more detail below with reference to the accompanying figures. These show: Fig. 1 a perspective view of a conventional linear guide in the form of a linear ball bearing; Fig. 2a a cross-sectional view of the linear ball bearing according to Fig. 1 perpendicular to its shaft axis; Fig. 2b an enlarged representation of a conventional ball feed channel with a round cross-section; Fig. 2c an enlarged representation of a conventional ball return channel with a round cross-section; Fig. 3a a cross-sectional view of a linear guide in the form of a linear ball bearing with ball guide channels according to an embodiment of the present invention; Fig. 3b an enlarged representation of a ball feed channel according to an embodiment of the present invention; Fig. 3c an enlarged cross-sectional view of a spherical channel according to an embodiment of the present invention; Fig. 4a Cross-sectional views of various ball return channels open towards the shaft according to embodiments of the present invention; Fig. 4b Cross-sectional views of possible embodiments of closed ball return channels; Fig. 4c a cross-sectional view of an embodiment of a ball guide channel with a four-point contact; and Fig. 5 a perspective view of a cage or bushing for a linear ball bearing, according to an embodiment of the present invention, and an effect of draft angles in axial direction on a cage inside and a width of the pocket sag.

[0037] In the following exemplary description of some embodiments, identical reference numerals refer to identical, similar or functionally identical components.

[0038] The Fig. Figure 3a shows a cross-sectional view of a linear guide according to a possible embodiment of the present invention. The linear guide is shown here, by way of example, as a linear ball bearing in which a bushing or cage 12 cylindrically surrounds a shaft 11. While the shaft 11 is typically made of steel, the bushing or cage 12 is usually an injection-molded part, for example made of plastic, produced by an injection molding process.

[0039] Based on the Fig. The linear guide shown in 3a differs from the one initially described based on the Fig. 1 and Fig. The conventional linear guide described in Section 2 is essentially defined by the geometric shape of the ball guide channels 30-1 to 30-6, which are arranged circumferentially or tangentially 39 of the bushing 12 and extend axially, i.e., in the direction of the shaft axis. Each of the ball guide channels 30-1 to 30-6 comprises a ball feed channel 31 and a ball return channel 32. A ball guide channel, or a ball feed or ball return channel, is at least partially bounded by a lateral surface extending circumferentially or tangentially 38 of the ball guide channel. This means that a ball guide channel can be either closed or partially open.

[0040] Based on the Fig. In the embodiment shown in Figure 3a, both the ball feed channels 31 and the ball return channels 32 are partially open (towards the shaft 11) ball guide channels. In particular, the ball return channels 32 are designed such that at least three predefined contact surfaces 37-1 to 37-3, spaced apart from one another along the circumferential direction 38 of the outer surface, are provided for a ball 17 circulating in a ball return channel 32 during operation of the linear guide, along which the ball 17 can roll or be guided. The ball feed channels 31 are designed such that at least three predefined contact surfaces 36-1 to 36-3, spaced apart from one another along the circumferential direction 38 of the outer surface, are also provided for a ball 17 held or guided in the ball feed channel 31 in the absence of a shaft, along which the ball 17 can roll in the absence of a shaft 11.During operation with shaft 11, i.e. under load, the balls 17 roll in the feed channel 31 only between the shaft 11 and counter raceway piece 14 (contact point 36-3).

[0041] According to the invention, the at least three contact points or surface sections 36-1 to 36-3 and 37-1 to 37-3 are formed by the circumferential surface of the ball guide channel 31, 32 having projecting and recessed circumferential surface sections in a radial direction perpendicular to the circumferential direction 38 of the ball guide channel and pointing towards the interior of the ball guide channel 31, 32, wherein the contact surfaces or areas 36-1 to 36-3 and 37-1 to 37-3 are formed by projecting circumferential surface sections spaced apart from one another in the circumferential direction of the ball guide channel. This can be seen in particular from the enlarged illustrations of a ball feed channel 31 and a ball return channel 32 of the Fig. 3b, Fig. Understand 3c.

[0042] The Fig. Figure 3b shows an enlarged view of a ball guide channel 31 according to an embodiment of the present invention. The ball guide channel 31 is bounded on one side by the cage 12 and on the other side by the raceway 23 located on the shaft surface and the counter-raceway 24 provided by the counter-raceway section 14. According to the embodiment shown here, the lateral surface sections of the ball guide channel 31 formed by the cage 12 have a sectionally polygonal cross-section. The ball guide channel 31 thus has a cross-section that corresponds to a polygon open downwards (towards the shaft 11) and / or upwards (towards the counter-raceway 24). In other words, the ball guide channel 31 can have a polygonal, in particular a multi-sided, cross-section in a plane perpendicular to an axial extension of the ball guide channel 31. For example, it can be an octagonal, i.e.,The ball guide channel 31 has an octagonal cross-section. Contact surfaces or areas are formed at the points designated by reference numerals 36-1 to 36-3 within the ball guide channel 31, which is at least partially or sectionally polygonal. These contact surfaces allow the ball 17 to roll on these surfaces, at least when unloaded (i.e., without the shaft 11 present). The radially outer contact area 36-3 in the guide channel 31 is provided by the counter-running track 24. A radially inwardly directed opening 41 of the ball guide channel 31, which can also be described as a pocket opening, is located in the radially inner area of ​​the cage 12 towards the shaft 11. The polygonal cross-section of the ball guide channel 31 allows the radially inner contact areas to be formed.The contact areas 36-1, 36-2, pointing towards the shaft passage, are positioned such that contact with the ball 17 does not occur at the material peaks or the opening end regions of the pocket passage 41, as indicated by the dashed circles. The polygonal cross-sectional contour of the ball guide channel 31 thus allows the rolling path of the ball 17 in the channel 31 to be shifted radially outwards from the material peaks at the pocket passage 41. This prevents the formation of a webbing layer between a radially inner surface (shaft bore) of the cylindrical cage 12 and radial slides of an injection mold from leading to malfunctions of the linear bearing as quickly, and eliminates the need for immediate mold correction.

[0043] In the ball guide channel 31, a surface of the shaft 11 forms a raceway for the balls 17 which circulate endlessly in the ball guide channels 31, 32, and the cage or guide carriage 12 forms a counter-raceway for the endlessly circulating balls 17. The ball guide channel 31 is designed according to the Fig. 3b is designed such that at least two radially inwardly projecting and circumferentially spaced-apart cylindrical surface sections 36-1, 36-2 of the ball feed channel 31, without the presence of the shaft 11, together with the counter-running track 24, serve as contact surfaces for a ball 17 guided in the ball feed channel 31 between pocket passage 41 and counter-running track 24.

[0044] The Fig. Figure 3c shows an enlarged representation of a ball return channel 32 according to an embodiment of the present invention.

[0045] The ball return channel 32 corresponding to the ball feed channel 31 is also polygonal, in particular octagonal, according to the illustrated embodiment. While the balls 17 are guided in the return channel 32, they are not under load. This means that they do not roll between a running surface on the guide rail or shaft 11 and a counter-running surface in the bushing 12, but are merely returned, without load, in the ball return channel 32 along the axial extent of the guide carriage or bushing 12. Here, too, the polygonal cross-section results in three predefined contact areas 37-1 to 37-3 between the ball 17 and the cylindrical surface of the ball return channel 32, spaced apart from each other in the circumferential direction. The contact areas 37-1 to 37-3 belong to radially inwardly projecting sections of the cylindrical surface.In contrast, the remaining sections of the lateral surface are offset radially (outwards), preventing them from coming into direct contact with the sphere 17. This is due to the... Fig. The three-point contact shown in 3c results in an improved axial guidance of the rotating balls compared to the prior art 17.

[0046] The ball guide channel 32 is designed such that at least three radially inwardly projecting and circumferentially spaced-apart cylindrical surface sections 37-1 to 37-3 of the ball guide channel 32 serve as contact surfaces or areas for a ball 17 guided in the ball guide channel during operation of the linear guide.

[0047] The return channel 32 shown is merely an example, designed as a spherical channel open towards the shaft 11, meaning that it is not closed in the radial direction inwards, i.e., towards the shaft 11. Due to the contact points 37-1, 37-2 being positioned radially outwards compared to a conventional round cross-section, the formation of a webbing layer during the manufacturing of the cage 12 in the passage area 45 between the return channel 32 and the shaft 11 is less critical.

[0048] Geometrically, the contact points 37-1 to 37-3 can be arranged in the circumferential direction 38 along the lateral surface of the ball guide channel 32 such that surface normals through the contact points 37-1 to 37-3 intersect at a point 42 of the cross-sectional plane, which essentially corresponds to a center point of the ball 17 guided in the ball guide channel 32. In the following, based on the Fig. In the embodiment shown in Figure 3c, the surface normals each enclose an angle of substantially 120°. With generally n contact points 37-1 to 37-n, an angle between two adjacent surface normals of substantially (i.e., taking into account manufacturing tolerances) 360° / n may be advantageous.

[0049] At the in Fig. 3c, indicated by arrows 46 and set back from the contact surfaces, which are not in contact with the ball 17, can, according to some embodiments, be provided with draft angles in the axial direction for injection molding. That is, in the direction of the bushing or cage rotation axis, the set-back sections of the cylindrical surface marked by arrows 46 can be slightly inclined. This means that at least one section of the cylindrical surface of the ball guide channel 32, which does not serve as a contact surface or contact area for the ball 17 guided in the ball guide channel 32 during operation of the linear guide, can include a draft angle to facilitate removal of the cage 12, which is designed as an injection-molded part, from an injection mold.Furthermore, the spaces between the recessed, non-guiding cylindrical surface sections 46 of the ball guide channel 32 and the ball 17 can serve as a lubricant reservoir, as indicated by reference numeral 44. In other words, the cavities of the channel 32 not used for ball guidance can also be used as a lubricant reservoir and may additionally or alternatively be designed with draft angles.

[0050] Exemplary embodiments of ball guide channels according to the present invention are not limited to the examples described so far. In the Fig. Figure 4a shows various geometric cross-sectional shapes for open ball return channels.

[0051] The return channel 32-1 shown on the left is the one already described above. Fig. The octagonal embodiment described in 3a-c has three contact points 37-1 to 37-3. The embodiment shown in the center has a hexagonal, i.e., six-sided, cross-sectional shape for the return channel. This channel is also designed to be open towards the shaft (not shown), i.e., a radially inner section of the spherical surface of the ball guide channel 32-2 is missing. The Fig. The embodiment 32-3 shown on the right in Figure 4a has a substantially circular cross-section in a plane perpendicular to the axial extent of the return channel, with radially inwardly projecting projections 47-1 to 47-3 arranged at predefined intervals along the circumferential surface of the channel 32-3 and serving as contact surfaces. The sections of the outer surface 48-1, 48-2, which are radially recessed relative to the projections 47-1 to 47-3, have a concavely rounded cross-section – similar to a conventional ball guide channel. Although the projections 47-1 to 47-3, which point towards the center of the ball channel, are arranged according to the Fig. 4a (right) shown as square, according to other embodiments these radially inwardly pointing projections 47-1 to 47-3 can, for example, also be convexly rounded to form contact surfaces for the ball 17 guided inside the channel 32-3.

[0052] It should also be mentioned that exemplary embodiments also allow combinations in which a lateral surface is partly rounded and partly polygonal (i.e., angular, flat).

[0053] In all embodiments, the free spaces around the sphere 17 resulting from the projections and the recessed sections of the outer surface (i.e., the gap between the sphere 17 and the recessed section of the outer surface) can be used as a lubricant reservoir.

[0054] After based on the Fig. 4a where some possible embodiments for open ball channels for ball return have been explained, shows the Fig. 4b Two possible embodiments for closed ball return channels 32-4, 32-5.

[0055] The ball return channel 32-4 (left) is an octagonal, closed ball channel with three radially projecting (i.e., pointing towards the interior of the ball) and five recessed sections of its outer surface. The ball guide channel 32-5 corresponds to the open ball guide channel 32-3 described above. The closed ball guide channel 32-5, with its otherwise essentially round cross-section, has radial projections 47-1 to 47-3 arranged at predefined intervals along its outer surface, serving as contact surfaces. The remaining outer surface sections 48-1 to 48-3 are recessed and, as described above, can be used as a base for a lubricant reservoir.

[0056] Depending on the number of radially inwardly projecting and circumferentially spaced protruding cylindrical surface sections provided, more than three contact surfaces or areas for guiding the balls 17 within a ball guide channel can be realized. This is shown in the Fig. 4c an embodiment of a ball channel 32-6 open towards the shaft, which is designed such that four predefined contact surfaces 37-1 to 37-4 are provided for a ball 17 circulating in the ball guide channel 32-6 during operation of the linear guide and spaced apart from each other in the circumferential direction along the outer surface, on which the ball 17 can roll.

[0057] The Fig. Figure 5 shows a guide carriage or cage 50 that can be arranged on a (not shown) guide rail, i.e. a guide carriage or cage that can be arranged on a guide rail or shaft, which has a plurality of ball guide channels 51, each of which has a polygonal cross-section, so that at least three predefined contact surfaces spaced apart in the circumferential direction are provided for guiding balls 17 circulating in the guide channels 51, on which the balls 17 can roll.

[0058] Conical pocket openings due to draft angles, as found in the [unclear text], can be created by means of ball guide channels according to embodiments of the present invention. Fig.The disadvantages indicated by the dotted lines 52 can be avoided. This disadvantage can be eliminated or reduced with a ball guide channel modified according to exemplary embodiments of the present invention, which has predefined contact points, since draft angles can be incorporated on the sections of the cylindrical surface that are not in contact with the ball 17. In conventional designs, this results in a conical shape of the pocket (opening elongated hole of the ball channel). The shape of the ball channel proposed according to exemplary embodiments allows the shape of the pocket to remain parallel over its entire length.

[0059] The features disclosed in the foregoing description, the following claims and the drawings can be important for the realization of the invention in its various embodiments, both individually and in any combination.

[0060] Although some aspects have been described in connection with a device or a linear guide, it is understood that these aspects also represent a description of a corresponding process, in particular a manufacturing process or a process for operating a linear guide, so that a block or component of a device is also to be understood as a corresponding process step or as a feature of a process step, for example, for manufacturing or operating a linear guide. Similarly, aspects described in connection with or as a process step also represent a description of a corresponding block or detail or feature of a corresponding device.

[0061] The embodiments described above merely illustrate the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be obvious to other people skilled in the art. Therefore, it is intended that the invention is limited only by the scope of protection set forth in the following claims and not by the specific details presented in the description and explanation of the embodiments. Reference symbol list 10 Conventional linear guides 11th wave 12 guide carriages, bushings, cages 13 rolling element row 14 Counter-track insert, -piece 15 Deflection range 16 final ring 17 rolling elements 19 Seal 20 ball guide channel including ball feed and ball return 21 conventional ball feed channel 22 conventional ball return channel 23 Rolling element raceway on shaft 24 Opposite track 26 Contact point in conventional ball feed channel 27 Contact point in conventional ball return channel 30 Ball guide channel according to an embodiment 31 Ball feed channel according to an embodiment 32 Ball return channel according to an embodiment 36 contact points in the ball feed channel according to the invention (unloaded) 37 contact points in the ball return channel according to the invention 38 Circumferential direction of the lateral surface of the ball guide channel 39 Circumferential direction of the cylindrical cage or bushing 41 Bag passage 42 Center of the sphere 44 Lubricant depot 45 Passage area between return channel and shaft 46 recessed lateral surface sections 47 Superior or preceding shell surface section 48 Recessed lateral surface section 50 guide carriages, bushings, cages according to an exemplary embodiment 51 Ball guide channel according to an embodiment 52 Draft angle

Claims

[1] A ball guide channel (30; 31; 32; 51) for a guide carriage (12; 50) of a ball-bearing linear guide which can be arranged linearly movable on a guide rail (11), wherein a ball feed channel (31) and a ball return channel (32) of the ball guide channel (30; 31; 32; 51) are each at least partially bounded by a circumferential surface (38), and wherein the ball guide channel (30; 31; 32; 51) is designed such that for a ball (17) circulating in the ball guide channel (30; 31; 32; 51) at least three predefined contact surfaces (36; 37; 38) spaced apart from each other in the circumferential direction are provided.47) are provided, on which the ball (17) can roll, so that at least three-point contact is maintained between the ball (17) and the lateral surface of the ball feed channel (31) and the ball return channel (32) in an unloaded state, and the ball (17) in a loaded state can roll in the ball feed channel (31) only between the guide rail (11) and a contact surface (36-3) of the ball feed channel (31), wherein the lateral surface has lateral surface sections (46; 48) projecting and recessed in a radial direction perpendicular to the circumferential direction (38) and pointing towards an interior of the ball guide channel (30; 31; 32; 51), wherein the contact surfaces (36; 37; 47) are formed at least partially by lateral surface sections projecting and spaced apart from each other in the circumferential direction (38). [2] The ball guide channel (30; 31; 32; 51) according to claim 1, wherein the ball guide channel has a polygonal cross-section in a plane perpendicular to an axial extension of the ball guide channel. [3] The ball guide channel (30; 31; 32; 51) according to one of the preceding claims, wherein the guide rail is designed as a shaft (11) which the guide carriage (12) surrounds in a cylindrical manner. [4] The ball guide channel (30; 31; 32; 51) according to one of the preceding claims, wherein a surface of the guide rail (11) forms a raceway (23) for balls (17) circulating endlessly in the ball guide channel, and wherein the guide carriage (12; 50) comprises a counter-raceway (24) for the endlessly circulating balls (17), wherein the ball guide channel (30; 31; 32; 51) is designed such that at least two radially inwardly projecting and circumferentially spaced-apart cylindrical surface sections (36; 37; 47) of the ball guide channel together with the counter-raceway (24) serve as contact surfaces (36; 37; 47) for a ball (17) guided in the ball guide channel (30; 31; 32; 51). [5] The ball guide channel (30; 31; 32; 51) according to one of the preceding claims, wherein the ball guide channel is designed such that at least three radially inwardly projecting and circumferentially spaced-apart cylindrical surface sections (36; 37; 47) of the ball guide channel serve as contact surfaces (36; 37; 47) for a ball (17) guided in the ball guide channel. [6] The ball guide channel (30; 31; 32; 51) according to one of the preceding claims, wherein surface normals intersect at contact points between the ball (17) and the at least three predefined contact surfaces (36; 37; 47) at a point (42) of the cross-sectional plane which corresponds to a center point of the ball (17) guided in the ball guide channel (30; 31; 32; 51). [7] The ball guide channel (30; 31; 32; 51) according to one of the preceding claims, wherein at least one cylindrical surface section (46; 48) of the ball guide channel, which does not serve as a contact surface for a ball (17) guided in the ball guide channel (30; 31; 32; 51) during operation of the linear guide, comprises a draft angle to facilitate removal from an injection mold. [8] The ball guide channel (30; 31; 32; 51) according to one of the preceding claims, wherein a lubricant reservoir (44) is formed between at least one cylindrical surface section (46; 48) of the ball guide channel, which does not serve as a contact surface for a ball (17) guided in the ball guide channel (30; 31; 32; 51) during operation of the linear guide, and the ball. [9] A guide carriage (12; 50) for a ball-bearing linear guide, wherein the guide carriage (12; 50) has a ball guide channel (30; 31; 32; 51) for endlessly rotating rolling elements (17) according to one of the preceding claims.

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