DE102015203220A1 - Linear Bushing Housing - Google Patents

Abstract

Disclosed is a housing (101, 201, 301) for two linear ball bearings for guiding a curved shaft, comprising: a body (109) having a passage opening (111) for the shaft, the passage opening being at least partially defined by a first inner seat surface (113) for a first linear ball bearing (103) and a second inner seat surface (115) for a second linear ball bearing (107) is defined, wherein the first inner seat surface (113) and the second inner seat surface (115) are formed such that the first linear ball bearing and the second linear ball bearing relative tilted to each other (α) in the housing (101) can be used.

Description

The present invention relates to a housing for two linear ball bearings for guiding a curved shaft and a bearing system comprising the housing.

A linear ball bearing (also called a linear bearing) is used for guiding or low-friction guidance of e.g. cylindrical shaft provided along a longitudinal direction of the shaft. In this case, there may be a point contact between the supporting balls of the linear ball bearing and the shaft to be guided, wherein the supporting balls roll upon movement of the shaft relative to the linear ball bearing along a groove of a raceway plate. In the linear ball bearing a plurality of rows of balls may be provided which roll in or on an associated raceway plate. The balls roll in an annular, i. closed groove on a raceway plate substantially in the axial direction, i. Longitudinal direction of the shaft to be guided, wherein the balls roll in the groove in a circumferential direction, but axially roll in different directions. At the axial ends of the groove, the balls are deflected, so that there is an entry or exit of the balls in each supporting or non-supporting row.

To guide a straight shaft, one or more linear ball bearings can be inserted into a housing, in particular axially spaced from each other. Thus, a guide longer waves can be achieved.

In practice, however, it has been found that housing for linear ball bearings and storage systems formed therefrom are not suitable for storing all types of shafts or under all circumstances.

An object of the present invention is thus to provide a housing for at least two linear ball bearings and a bearing system which is able to store a shaft under special loads or with special geometries. In particular, it is an object of the present invention to provide a housing for at least two linear ball bearings or a bearing system, which is designed for supporting a curved shaft.

The object is achieved with the objects of the independent claims. The dependent claims specify particular embodiments of the invention.

According to an embodiment of the present invention, a housing (support structure, mounting frame) for (at least) two linear ball bearings (which are substantially substantially cylindrical in shape) for guiding (and supporting along a longitudinal direction) a curved one (in particular curved with a constant radius of curvature) provided wave. In this case, the housing has a body (made of metal and / or plastic, for example) with a passage opening (eg bore or opening obtained by drilling and / or milling) for a shaft (in particular with a circular cross-section or with a cross-section, which of the Circular shape deviates), wherein the passage opening at least partially (ie only in sections along the longitudinal direction, in particular at the ends of the passage opening) by a first inner seat surface (a radially inwardly facing surface for contacting with a linear ball bearing) for a first linear ball bearing and a second inner seat surface is defined for a second linear ball bearing (ie is at least partially limited by the first inner seat surface and the second inner seat surface). In this case, the first inner seat surface and the second inner seat surface are designed (in particular in their orientation, arrangement or geometry) that the first linear ball bearing and the second linear ball bearing are tilted relative to each other inserted into the housing.

The linear ball bearings are e.g. then tilted into the housing used, if the Zylinderymmetrieachsen are not parallel to each other. The first linear ball bearing can rest directly on the first inner seat surface and the second linear ball bearing can bear directly against the second inner seat surface, in particular be pressed, so that the two linear ball bearings are fixed for a bearing operation within the housing. During a bearing operation of a bearing system comprising the housing, however, the first and / or the second linear ball bearing (in addition) can be dynamically tilted, in particular during entry or exit of balls, which are included in the linear ball bearings. The first inner seat surface and / or the second inner seat surface may be e.g. may be integrally formed with the body (i.e., integral) or may be formed by one or more other elements which co-operate with the body.

The housing may be designed such that a predetermined tilting of the first linear ball bearing is achieved relative to the second linear ball bearing, for example by the first inner seat surface and / or the second inner seat surface having a certain predetermined relative tilt. Alternatively, the housing may be configured such that the first linear ball bearing and the second linear ball bearing can assume a plurality of different relative tilting without, for example, the geometry of the first inner seat surface and / or the second inner seat surface to a certain fixed Tilting to be limited. Thus, the housing together with corresponding linear ball bearings allows guiding a shaft, which is bent, for example under load or in the unloaded case has a desired curvature or bending. However, the housing can also be used advantageously for supporting straight shafts, as they may also inadvertently have temporary bends or bends in operation, depending on the application, which can make it difficult to guide or store with conventional linear bearing systems.

The first inner seat surface and the second inner seat surface may be e.g. be tilted relative to each other according to a curvature (in particular constant curvature) of the shaft to be supported. The first inner seat surface may e.g. have a first longitudinal axis, which is e.g. along the longitudinal direction in the center of the inner seat surface can run. An analog second longitudinal axis may comprise the second inner seat surface. Both inner seating surfaces may e.g. have a cylindrical symmetry. Tilting of the first and second inner seating surfaces relative to each other may be present when e.g. the first longitudinal axis is tilted at an angle (greater than 0 °) relative to the second longitudinal axis, i. especially not parallel. The higher the curvature of the shaft to be supported, the greater the tilting of the first inner seat surface relative to the second inner seat surface. By tilting the inner seating surfaces relative to each other, two linear ball bearings can be mounted with a predetermined tilt relative to each other within the housing, wherein the tilt is matched to the predetermined curvature of the shaft to be stored. Thus, an effective storage of the shaft can be achieved and it can be guaranteed good running properties of the balls.

The first and / or the second inner seat surface may e.g. have a geometry of a cylinder jacket inner surface and the cylinder symmetry axes of the inner seat surfaces may e.g. be tilted relative to each other at an angle (e.g., between 0 ° and 20 °, between 0 ° and 5 °, in particular between 0.5 ° and 3 °). The inner seating surfaces may thus be e.g. be made in a simple manner by drilling and / or milling. Furthermore, conventionally available linear ball bearings may have an outer surface with cylinder geometry, so that they can be easily installed within the housing.

In addition or as an alternative to the fixedly adjustable tilt relative to one another, a dynamic tiltability (variable tilting during operation) of the mounted linear ball bearings may be provided.

The first inner seat surface may be disposed along a longitudinal direction of the through hole (corresponding to a longitudinal direction, for example, straight or along a circular arc, the shaft to be supported) at a distance from the second inner seat surface. Thus, an exact guidance of the shaft to be stored can be achieved.

The housing (or even an entire storage system) may e.g. have a mirror symmetry, wherein a mirror plane can be oriented perpendicular to a longitudinal direction of the through hole and can be arranged in a center of the through hole between the inner seating surfaces. Thus, manufacture can be simplified if e.g. the housing is composed of two parts formed in mirror image. Thus, e.g. the inner seat surfaces are integrally formed with the body.

According to embodiments of the present invention, e.g. the first inner seat surface and / or the second inner seat surface may be convex (e.g., a convex annular surface). According to this embodiment, the linear bearings or linear ball bearings could be insertable into the housing without having a predetermined tilt relative to each other. The two linear ball bearings could e.g. be inserted into the housing such that their axes of symmetry or longitudinal axes are parallel and in particular collinear with each other. Nevertheless, once installed in the housing, the linear ball bearings may tilt relative to one another during operation (e.g., depending on the shaft geometry and also during ingress of the balls in the linear ball bearings). However, it can be disadvantageous that the respective race plates of the linear ball bearings idealized produce only a point contact with the convex inner seat surface, which can limit the load bearing capacity or load capacity of the bearing system. This can be counteracted, at least partially, by the inner seating surface being convex, however, at least in an area provided as the contact area, almost flat, so that effectively and practically a contact surface between the raceway plates and the respective inner seating surfaces is achieved is.

A respective such convex inner seat surface may be formed, for example, by a ring-shaped first and / or second element separate from the body, in particular a snap ring. If a ring-shaped first and / or second element which is separate from the body is provided, the through-opening can, for example, have at least one annular groove (or recess) against which the respective annular element bears, and thus is in contact. Thus, the annular member can be advantageously held in position so as to Tilt the linear ball bearings relative to each other during operation to allow.

According to an embodiment of the present invention, there is further provided a bearing system having a housing according to any one of the preceding embodiments, and two linear ball bearings fixed to the respective inner seat surfaces (particularly, press-fitted) for supporting a shaft when moving longitudinally. The bearing system may comprise further linear ball bearings, for example three, four, five or more than five linear ball bearings.

The linear ball bearings may each have a plurality of raceway plates, in each of which a circumferential row of balls is provided. The circulating row of balls can thereby run essentially in the axial direction or in two opposite axial directions and comprise a load-bearing row and a non-load-bearing row of balls.

The raceway plates of the first and / or the second linear ball bearing can in each case rest against the respective inner seat surfaces over a total axial extent with respective radial outer surfaces (surfaces facing away from the side on which the balls run). Thus, an exact relative orientation of the linear ball bearings relative to each other can be achieved, e.g. a desired tilting of the two linear ball bearings can be set and maintained relative to one another exactly, since the respective race plates of the linear ball bearings are maximally supported or supported by the respective inner seat surfaces.

According to other embodiments of the present invention, the raceway plates of the first and / or the second linear ball bearing (only) over 20% to 50% of a total axial extent of the respective raceway plates on the respective inner seat surfaces, in particular cylinder geometry having. Although a tilting or a desired (preset) tilting of the linear ball bearings can be achieved relative to one another, a certain dynamic tilting of the linear ball bearings beyond this can be made possible relative to one another since the linear ball bearings, in particular their raceway plates, do not extend over the entire axial extent. ie not fully supported by the respective inner seating surfaces and aligned so that there is some play (e.g., +/- 10 °, or +/- 5 °) for tilting. The percentage can be adjusted depending on the application and can be optimized in particular with regard to desired effects.

In this case, the raceway plates can be free in particular at axial ends or not rest against the respective inner seating surfaces in order to allow a tilting of the raceway plates relative to a longitudinal direction of the through-opening during a deflection or a running in and / or out of running within the raceway plates balls , Thus, a running behavior of the balls during storage can be further improved.

The storage system may e.g. for supporting a shaft with a diameter of between 2 mm and 100 mm, in particular 3 mm and 50 mm, with a curvature greater than 200 mm, in particular between 500 mm and 10 km. This can support a storage of conventional waves and curvatures occurring in practice. An axial length of the linear ball bearings may e.g. be between 5 mm and 200 mm, in particular between 10 mm and 50 mm, wherein the raceway plates may be made in particular of hardened steel, wherein balls are held in raceways in the raceway plates, in particular by means of a plastic cage.

In conventional linear bearing units, it may be difficult or impossible to support a shaft bent with a certain radius, since when mounting on the shaft a conventional system can become jammed. According to embodiments of the invention, the bearing seats in the housings can be inclined at a certain angle (depending on the radius of the shaft) to ensure smooth running. Conventional systems can not support bending of a shaft to be supported beyond a certain amount. Due to an inclination of the bearing seats, adapted to the respective radius of the curved shaft, a smooth running and the function of the unit can be ensured. The "exposure" of the track plate ends, e.g. can be realized by introduced punctures, can cause the ends of the raceway plates exposed to the housing bore diameter and thereby "feather" something when entering and leaving the rolling elements and can improve due to the running properties.

Embodiments of the present invention will now be described with reference to the accompanying drawings. The invention is not limited to the illustrated or described embodiments.

1 illustrates in a schematic cross-sectional view a storage system according to an embodiment of the present invention;

2 illustrates a detailed view of the in 1 illustrated storage system;

3 illustrates in a schematic sectional view a storage system according to another embodiment of the present invention;

4 illustrates a detailed view of the in 3 illustrated storage system; and

5 11 illustrates a partial view of a storage system according to yet another embodiment of the present invention.

This in 1 and 2 in schematic sectional views illustrated storage system 100 has a housing 101 for a first linear ball bearing 103 and a second linear ball bearing 107 to guide an unillustrated slightly curved shaft. The housing 101 has a body 109 with a passage opening 111 for the shaft, not shown, wherein the passage opening 111 at its two ends or in certain axial areas by a first inner seat surface 113 for the first linear ball bearing 107 and by a second inner seat surface 115 for the second linear ball bearing 103 is defined. Straight 117 represents a hypothetical axis of a cylindrical passage opening 111 and the axis 119 indicates the cylinder axis of symmetry of the first inner seat surface 113 , How out 1 and also out 2 can be seen, is the Zylindersymmetrieachse 119 the first inner seat surface 113 opposite the straights 117 inclined by an angle α, which may be between 0.5 ° and 5 °, for example. Similar is a cylindrical axis of symmetry 121 the second inner seat surface 115 relative to the line 117 tilted by the same angle α (mirror image). This is the interior seating surfaces 113 . 115 formed such that the first of the linear ball bearings 103 and the second linear ball bearing 107 tilted relative to each other in the housing 101 can be used. This allows a bearing of a curved shaft. The angle α can be adjusted according to a curvature of a shaft to be supported.

The detailed view of the 2 shows here in greater detail the right part of in 1 fully illustrated storage system 100 with the first linear ball bearing 103 which is in the passage opening 111 on the first inner seat 113 is fitted. Further, raceway plates 123 of the first linear ball bearing 103 in 2 schematically illustrated, which have arranged on the radially inner side of each unillustrated balls along an annular groove, which roll in operation. The radially outer surfaces 125 the raceway plates 123 are with the first inner seat surface 113 in contact, especially in press contact, and thus stabilize and position the raceway plates 123 so they are especially tilted towards the straights 117 are aligned and in particular also tilted with respect to similar or same raceway plates of the second linear ball bearing 107 , As in 2 Illustrated are the track plates 123 an axial extent al and lie with their entire axial extent al on the first inner seat surface 113 at. This can be a particularly accurate alignment of the raceway plates 123 be achieved.

How out 1 it can be seen, are the first linear ball bearing 103 and the second linear ball bearing 107 (and thus also the first inner seat surface 113 and the second inner seat surface 115 ) axially spaced by a distance ad. As further out 1 it can be seen has the storage system 100 a mirror symmetry, wherein a mirror plane 127 perpendicular to a longitudinal direction 119 the passage opening 111 in the center between the seats 113 and 115 is arranged.

3 and 4 illustrate a warehouse system 200 according to another embodiment, wherein in structure and / or function similar features are provided with reference numerals, which are different from the reference numerals of the storage system 100 differ only in the first digit.

How out 2 shows, has the first inner seat surface 113 an axial extent as that is greater than (or equal to) the axial extent of the raceway plates 123 , This will be the raceway plates 123 at its full full axial extent al through the first inner seat surface 113 supported. A similar construction may be found in the second inner seat surface 115 or the second linear ball bearing 107 be provided.

Alternatively, however, may be provided for the two inner seats linear ball bearing a construction as in 3 and 4 is illustrated. How out 3 and 4 it can be seen have the first inner seat surface 213 and also the second inner seat surface 215 a smaller axial extent as, which is in particular smaller than the axial extent al of the raceway plates 223 , The ratio as / al can for example be between 20% and 50%. The first inner seat surface 213 has a cylinder geometry, is thus formed by an inner circumferential surface of a cylinder, which has an axis of symmetry 219 which is opposite to a straight line 217 and in particular also with respect to an axis of symmetry 221 the second inner seat surface 215 is inclined. The relative inclination of the symmetry axes 217 . 221 is 2 · α.

The radial outer surfaces 225 the raceway plates 223 lie with an axial extent as at the first inner seating surfaces 213 at. Due to the support of the track plates with axial extent as approximately in the center of the raceway plates 223 can the track plates 223 during an operation along the arrows 229 To perform tilting movements, in particular a running behavior during a run-in or run-out of balls, which in or on the raceway plates 223 be led to improve.

5 illustrates a schematic cross-sectional view of a storage system 300 according to another embodiment of the present invention, which is a housing 301 with a body 309 having. From the storage system 300 only one part is illustrated, which is a first linear ball bearing 303 Illustrates how it works within a through hole 311 within the housing or the body 309 is positioned. A first interior seat surface 313 is here by an inner surface of a snap ring 331 formed, which in the housing 301 in a groove 333 is inserted. The inner seat surface 313 can here in cross-section as a point-shaped contact surface or a point contact to a radially outer surface 325 the raceway plate 323 be considered. Due to the punctiform contact (in the cross-sectional view, in reality, there is a circular contact between the raceway plate 323 and the snap ring 331 given), the raceway plates can 323 along with arrows 329 tilted marked directions, in particular relative to the straight line 317 to be tilted, about an angle α, as in the 1 to 4 is illustrated. The snap ring 331 even as the seat 313 a convex surface on which the radially outer surface 325 the raceway plate 323 is applied.

LIST OF REFERENCE NUMBERS

100

storage system

101

casing

103

first linear ball bearing

107

second linear ball bearing

109

body

111

Through opening

113

first inner seat surface

115

second inner seat surface

117

axis

119

Symmetry axis of the first inner seat surface

121

Symmetry axis of the second inner seat surface

123

Race plate

125

radially outer surfaces of the raceway plate

127

Symmetry mirror plane

129

Kippbewegungsrichtungen

al

axial extension of the raceway plate

as

axial extent of the inner seat surface

α

tilt angle

331

snap ring

333

groove

Claims (10)

Casing ( 101 . 201 . 301 ) for two linear ball bearings for guiding a curved shaft, comprising: a body ( 109 ) with a passage opening ( 111 ) for the shaft, wherein the passage opening at least partially by a first inner seat surface ( 113 ) for a first linear ball bearing ( 103 ) and a second inner seat surface ( 115 ) for a second linear ball bearing ( 107 ), wherein the first inner seat surface ( 113 ) and the second inner seat surface ( 115 ) are formed such that the first linear ball bearing and the second linear ball bearing tilted relative to each other (α) in the housing ( 101 ) can be used. Housing according to claim 1, wherein the first inner seat surface ( 113 ) and the second inner seat surface ( 115 ) are tilted relative to each other according to a curvature of the shaft to be supported. Housing according to claim 1 or 2, wherein the first and / or the second inner seat surface ( 113 . 115 ) has a geometry of a cylinder jacket inner surface, wherein in particular cylinder symmetry axes ( 119 . 121 ) of the inner seat surfaces are tilted by an angle (2 · α). Housing according to one of the preceding claims, wherein the first inner seat surface ( 113 ) along a longitudinal direction ( 117 ) of the passage opening ( 111 ) spaced (ad) from the second inner seat surface (FIG. 115 ), wherein the housing ( 101 ) has in particular a mirror symmetry, wherein a mirror plane ( 127 ) perpendicular to a longitudinal direction ( 117 ) of the passage opening ( 111 ) and in a center of the passage opening between the inner seat surfaces ( 113 . 115 ) is arranged. Housing according to claim 1, wherein the first inner seat surface ( 113 ) and / or the second inner seat surface ( 115 ) is formed convex and in particular by a separate from the body annular first and / or second element, in particular a snap ring ( 331 ) is formed. Housing according to claim 5, wherein the passage opening ( 311 ) at least one annular groove ( 333 ), at which the respective annular element ( 331 ) is present. Storage system ( 100 . 200 . 300 ), comprising: a housing ( 101 ) according to one of the preceding claims; and two linear ball bearings ( 103 . 107 ), which at the respective inner seats ( 113 . 115 ) are arranged around a shaft when moving in the longitudinal direction ( 117 ) to store. Storage system ( 100 ) according to claim 7, wherein raceway plates ( 123 ) of the first and / or the second linear ball bearing ( 103 . 107 ) with respective radial outer surfaces ( 125 ) over an entire axial extent (al) at the respective inner seating surfaces (FIG. 113 . 115 ) issue. Storage system ( 200 ) according to claim 7, which is designed such that raceway plates ( 223 ) of the first and / or the second linear ball bearing ( 203 ) over 20% to 50% of a total axial extent (al) of the respective raceway plates at the respective inner seating surfaces (FIG. 213 ), in particular cylinder geometry having, rest, and in particular at axial ends of the raceway plates ( 223 ) are not present / free to tilt the raceway plates relative to a longitudinal direction ( 217 ) to allow the passage opening during a deflection or a running in and / or out of running within the track plates balls. Bearing system according to one of claims 7 to 9, wherein the bearing system for supporting a shaft with diameter between 2 mm and 100 mm, in particular 3 mm and 50 mm, with a curvature greater than 200 mm, in particular between 500 mm and 10 km is formed, wherein an axial length (ak) of the linear ball bearings ( 103 . 107 ) is between 5 mm and 200 mm, in particular between 10 mm and 50 mm, wherein the race plates ( 123 ) are made in particular of hardened steel, wherein balls are held in runways in the raceway plates, in particular by means of a plastic cage.

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