WO2008074295A2

WO2008074295A2 - Linear guide

Info

Publication number: WO2008074295A2
Application number: PCT/DE2007/002208
Authority: WO
Inventors: Rainer Eidloth; Ludwig Winkelmann
Original assignee: Schaeffler Kg
Priority date: 2006-12-20
Filing date: 2007-12-06
Publication date: 2008-06-26
Also published as: WO2008074295A3; DE102006060219A1

Abstract

The invention relates to a linear guide, having an outer guide part (4, 4') and an inner guide part (3, 3') supporting each other via rolling bodies (2), wherein rolling body raceways (10, 10', 11, 11 ') are configured on the guide parts (3, 3', 4, 4'), the raceways forming closed rolling body channels (6) in the mounted state, in which continuously revolving rolling body rows (5) are accommodated. In order to enable a better ratio of load-bearing capacity and construction width on the linear guide, and simultaneously make the same as unsusceptible to production and operation related tolerances as possible, the rolling bodies (2) are configured according to the invention as ball rollers having two side faces that are each symmetrically flattened from a ball base shape, and that are disposed parallel to each other, and the rolling body channels (6) are configured as ball roller channels having support regions (8), return regions (9), and deflection regions, and a cross-sectional profile that is adjusted to the rolling bodies (2) configured as ball rollers.

Description

Schaeffler KG Industriestr. 1 - 3, 91074 Herzogenaurach

Name of the invention

linear guide

description

Field of the invention

The invention relates to a linear guide, with an outer guide member and an inner guide member which are supported against each other via rolling elements, wherein on the guide parts Wälzkörperlaufbahnen are formed which form closed Wälzkörperkanäle in the assembled state, in which endless revolving Wälzkörperreihen are added.

Background of the invention

Linear bearings with rolling bearings have long been known and are used in many areas of mechanical and jig construction. Particularly in the case of linear guides consisting of profiled rails with revolving rolling bearings, for example for moving tools and workpieces, applications in food technology, medical technology, for movable supporting structures (portals) and in robot construction from the market ever higher load capacities and stiffness at the same time as small construction cross-section and low weight required.

The transmission of bearings takes place by a composite of rollers and sliding movement, the rolling elements are selected depending on the application and load type. The power of performance, ie the dynamic load rating based on the weight of the bearing, is decisive for the performance of the guide. Basically, the power weight is relatively high in cylindrical roller bearings. However, cylindrical roller bearings are only radially resilient. By contrast, the power-to-weight ratio of ball bearings is rather low. However, these are radially and axially resilient. Tapered roller bearings are axially and radially loadable at rather moderate power weights, but require a relatively large amount of space and are usually subject to higher rolling friction.

In known profiled rail guides often cylindrical rollers are used as rolling elements due to their high load capacity. In most cases, one, two or more circulating roller chains, on both sides of an inner guide part, in Wälzkörperkanälen which are formed by raceways on the guide members, respectively. The Wälzkörperkanäle are preferably arranged inclined in order to achieve a high rigidity and to distribute the external loads largely uniformly from all directions. By a uniform support of the acting static and dynamic forces on all sides a very smooth bearing with low wear and thus long life is sought. By way of example, the profiled rail guides of publications DE 41 40 042 C2, DE 4301 777 A1 and DE 102004035211 A1 may be mentioned for this purpose.

This type of profiled rail guides has already proven itself many times. However, they are relatively prone to angular errors. Due to hardly or at least only with great effort avoidable mold tolerances in the production, positional tolerances during assembly and deformations due to high loads during operation, the rolling elements in linear guides in practice ra- dial and axially acted upon. Owing to their linear contact between the cylinder jacket and a correspondingly flat raceway and its load capacity, which is essentially predetermined in the radial direction, cylindrical rolling elements can only insufficiently compensate for or absorb such production and operating tolerances. In particular, in the case of angular errors between a guide rail and a cassette or a support body encompassing the latter like a bow, the cylindrical rollers may tilt or run against the raceway walls at their end faces, as a result of which undesired increased rolling resistance and premature wear can occur.

Another problem of the cylindrical roller bearings is their comparatively large minimum size, which results from the longitudinal extent of the rolling elements, wherein this longitudinal extent is necessary to achieve the desired load capacity. Such profiled rail guides therefore offer little potential for reducing their size without having to simultaneously accept a reduction in their dynamic load rating or at least a deterioration in their rigidity.

On the other hand, known linear guides with ball bearings can basically be designed with a smaller axial length compared to cylindrical roller bearings, but have a load in a radial main direction, which is typical for profiled rail guides, owing to their comparatively low load rating and an effective surface area of the rolling elements rather suboptimal ratio of load capacity and width, and therefore meet even with today's requirements more often to their allowable load limits. From DE 199 40 654 C2, a linear guide is known in which a guide cassette is supported by support rollers on a guide rail. The support rollers have trapezoidal or prismatic tapered running surfaces at least in one edge region. The associated adjacent support roller tracks are adapted to the shape of the rollers. Due to the bevels, the rollers are guided laterally, while the center regions of the rollers absorb the applied radial forces.

Although the lateral guide prevents a reinforced edge load on the raceway side walls, which may be less loaded or eliminated altogether, if necessary, arranged therebetween side sliding washers. However, such a positive guide displaces an edge load within the rolling bearing in the region of the bevels described above, which may lead under circumstances to a rather unfavorable uneven load distribution over the relatively long support rollers with manufacturing tolerances. The linear guide also has - as explained above - a relatively large width.

Furthermore, from DE 695 18 785 T2 a guide roller unit is known, which is preferably provided as a rolling bearing with a curved guide for a chassis of a rail vehicle. The arrangement of the Wälzkörperkanäle is not inclined. Instead, a plurality, preferably three, Wälzkörperkanäle are arranged on flat side surfaces of an inner guide rail, so that an outer movable guide element supports an acting load in the vertical direction.

While ball rows are always provided in the two outer rolling body channels, a rolling body raceway for receiving rolling or barrel-shaped rolling elements can be provided in a middle section of the outer guiding element. As a result, a roller bearing with mixed rolling elements is formed. As a mating track of the rollers or tons serve the opposite planar side surfaces of the inner guide rail. These rolling elements can occur in a horizontal direction. long move the side surfaces of the guide rail, whereby they are able to avoid a displacement of the guide parts due to dimensional or angular errors.

A disadvantage of this rolling element bearing with mixed rolling elements is that although the inner roller chain can absorb offset errors. However, this horizontal compensation movement in the two outer conventional ball raceways is not or at most very limited possible, whereby the error compensation options of the guide are rather limited overall. Furthermore, due to the parallel arrangement of several rolling element rolling tracks with balls and optionally other additional rolling elements, a relatively large space requirement and a rather unfavorable power-to-weight ratio result. The mixed arrangement of balls and rollers or ball raceways and roller tracks is also relatively expensive construction and expensive to manufacture.

Object of the invention

The invention has for its object to provide a linear guide, which allows a better ratio of load capacity and width and at the same time as insensitive to manufacturing and operational tolerances.

Summary of the invention

The invention is based on the finding that with ball rollers as rolling elements, which are reduced in their axial length compared to balls on the substantially polluted spherical disc-shaped central part, particularly effective, especially compact and designed with high load capacity linear guides can be realized. Furthermore, the invention is based on the finding that with the help of ball rollers, where the Cross-sectional contact between the rolling element surface and the associated Wälzkörperlaufbahn runs over a circular line, in particular compared to cylindrical rollers, manufacturing errors and particularly angle errors and operational deformations during assembly or operation are largely compensated.

The invention is therefore based on a linear guide, with an outer guide member and an inner guide member, which are supported against each other via rolling elements, wherein on the guide parts Wälzkörperlaufbahnen are formed, which form closed Wälzkörperkanäle in the assembled state, in which endless revolving Wälzkörperreihen are added.

In addition, it is provided that the rolling bodies are designed as ball rollers with two symmetrically flattened from a spherical base and arranged parallel zueinan- arranged side surfaces and the Wälzkörperkanäle as ball roller channels with support areas, return areas and deflection and a trained as ball rolling elements cross-sectional profile.

By means of this structure, a particularly compact design of a linear guide with a high load-bearing capacity, in particular with an improved ratio of load-bearing capacity and width, and at the same time with an effective angular error compensation potential, is advantageously made possible.

In particular, due to the comparatively narrow design of the ball rollers, it is possible to reduce the overall width compared with conventional comparable linear guides with ball bearings without bearing losses. Compared with conventional linear guides with cylindrical roller bearings much narrower linear guides according to the invention can be provided with ball rollers, which also offer a significantly improved angular error compensation with related to the width comparable load bearing capacity and thus have a longer service life. Basically, with the same axial length or width of the linear guide, the space available can also be used for additional rows of rolling elements or for a higher rolling element - filling level of the linear guide to increase their carrying capacity. It is also possible to use the free space for additional measures to prevent deformation during operation, so as to further improve the rigidity of the linear guide or, if necessary, provide enlarged lubricant spaces to further increase the maximum service life of the bearing.

In addition to the radial load vector corresponding to its application, the ball rollers can also absorb inclined load components in their rolling motion without increased rolling resistance, whereby a limited degree of freedom of movement with respect to the position of the axes of rotation and thus a relative compensation movement between guide member and rolling elements during assembly or operation is possible. As a result, an angle error compensation possibility is created or at least improved in order to compensate for the manufacturing and / or operational errors or deformations already described above.

Ball roller bearings can be used particularly advantageously in a profiled rail guide, in which the inner guide member is formed as a profile rail and the outer guide member as a profile rail encompassing support body, the ball rollers as ball roller rows in two laterally of the rail trained, extending in the longitudinal direction O-shaped or at least an O-shape similar, cross-aligned and frontally deflected ball roller channels circulate, and the ball roller channels and according to the orientation of the axes of rotation of the ball rollers are inclined by 45 ° relative to the vertical or the longitudinal vertical axis of the rail.

An O-shaped longitudinal arrangement of Wälzkörperkanäle with a frontal deflection of the rolling elements in a cross-formation, ie frontal tig seen in an X-arrangement of two rows of rolling elements laterally of the rail, is known to achieve a high rigidity in a profiled rail guide. Due to the inventive use of ball rollers, this high rigidity and the associated torque-load capacity can be combined particularly advantageously with an angular error compensation and a reduced width.

In addition, it can be provided that the ball roller tracks of the ball roller channels have a hardened surface at least in the support areas. In particular, the rail of the guide can be inexpensively manufactured as a drawn steel profile and at least in the bearing raceway areas, for example by a heat treatment, have received the required hardness for the rolling bearing raceways.

By reducing the width compared to conventional profile rail guides using the ball roller bearing according to the invention results in a further advantage in principle a lower structural weight. Particularly advantageously, this weight reduction can be combined with further weight-reducing measures. For this purpose, it can further be provided that the inner guide part and / or the outer guide part are made of a lightweight construction material.

The profile rail and possibly also the tag body can be made, for example, from an aluminum extruded profile. As a material with the required hardness for the bearing surface of the ball rollers hardened steel profile wires or work hardened profile wires made of stainless steel, about stainless steel wires, relatively inexpensively formed with a ball-shaped profile and inserted into the aluminum body to form the ball roller raceways suitable.

Furthermore, it can be provided to reduce the manufacturing costs and to further reduce the weight not forming return areas of the ball roller channels as simple holes in the support body and to carry out the channel profile of the return areas as a plastic lining, which are produced for example in a cost plastic injection molding or molded by direct injection of plastic in the support body.

It is also particularly advantageous to design the deflecting regions of the ball-roller channels as plastic parts molded onto the end faces of the supporting body. This can conveniently be done in one operation with the production of the plastic liners of the return areas. Finally, to complete the ball roller bearing at the deflection simple plastic caps can be provided.

The combination of the weight-saving aluminum construction with raceways made of hardened profile wires and the Baubreiter reducing and shape and deformation error compensating ball roller bearings can thus be provided with a particularly high performance weight at the same time a particularly compact design and a life-enhancing angle error compensation option a cost-effective profile rail guide.

Brief description of the drawings

The invention will be explained in more detail below with reference to the accompanying drawings of some embodiments. Show:

FIG. 1 shows a linear guide designed as a profiled rail guide with a ball roller bearing in a cross-sectional view,

Figure 2 shows a second embodiment of the profiled rail guide with a rail made of aluminum, and Figure 3 shows a third embodiment of the profiled rail guide with a rail made of aluminum and a support body made of aluminum.

Detailed description of the drawings

FIG. 1 therefore shows a linear guide designed as a profiled rail guide 1, in which rolling bodies 2 designed as ball rollers are provided. The profiled rail guide 1 has a trained as a rail inner guide member 3, which is encompassed by a trained as a support body outer guide member 4 like a bow or U-shaped. The support body 4 is supported by four rows of rolling elements 5 on the rail 3 from.

This ball roller rows 5 run in the side of the rail 3 and arranged in the longitudinal direction O-shaped rolling element 6 endlessly. In this case, a pair of channels 6 is cross-over and arranged at 45 ° - inclination to the vertical longitudinal axis 7 of the profiled rail guide 1, so that when viewed from the front side each gives a lateral X-arrangement, as indicated at the drawn axes.

The ball roller channels 6 in each case consist of a support area 8, a return area 9 and two frontal Umlenkbereich not shown. The support areas 8 each have a profile rail side and a support body side rolling element track 10 and 11, the contour of which is adapted in each case to the spherical surface of the ball rollers 2. Laterally, the ball rollers 2 are guided by correspondingly formed side walls of the Wälzkörperkanäle 6, so that the cross-sectional profile of the Wälzkörper- channels 6 is adapted to the ball rollers 2.

The profiled rail side walls are low in terms of manufacturing technology as separately insertable or molded directly from plastic side components Ie 13 trained. The return areas 9 are made as holes in the support body 4, which are ejected with hollow plastic liners 12, in which the ball rollers 2 are received with a guide game, so that they can rotate smoothly and without tilting. In an analogous manner, the deflecting regions, not shown, are also produced as plastic injection molded parts and advantageously protected by (also not shown) plastic caps and completed to the outside.

The profiled rail guide 1 shown in FIG. 1 represents a basic form in which the guide parts 3 and 4 are integrally connected to the associated raceways 10, 11. Preferably, the rail 3 and the support body 4 are formed therein as drawn steel profiles and the raceways 10, 11 cured by a known heat treatment process.

FIG. 2 shows a profiled rail guide 1 'in which a profiled rail 3' is produced as an aluminum extruded profile. The profile rail side ball roller raceways 10 'are each formed by an inserted into the rail 3' hardened profile wire 14, for example, a cold-worked Nirosta profile wire.

3 shows a profiled rail guide 1 ", in which both the profiled rail 3 'and a supporting body 4' are produced as extruded aluminum profiles. In addition, the counter tracks 11 'of the ball rollers 2 are also formed by hardened profile wires 15 inserted into the carrier body 4', wherein these profile wires 15 are advantageously flattened on the rear side for space and stiffness reasons.

LIST OF REFERENCE NUMBERS

1 1, 11 ', 11 "profile rail guide

2 rolling elements

3, 3 'inner guide part

4, 4 'outer guide part

5 row of rolling elements

6 rolling element channel

7 axis

8 support area

9 return area

10, 10 'rolling element track

11, 11 'Wälzkörperlaufbahn

12 plastic linings

13 sidewall component

14 profile wire

15 profile wire

Claims

Schaeffler KG Industriestr. 1 - 3, 91074 HerzogenaurachPatentansprüche

1. Linear guide, with an outer guide member (4, 4 ') and an inner guide member (3, 3') which are supported against each other via rolling elements (2), wherein on the guide members (3, 3 ', 4, 4') Wälzkörperlaufbahnen (10, 10 ', 11, 11') are formed, which form in the assembled state closed Wälzkörperkanäle (6) in which endlessly circulating Wälz- body rows (5) are added, characterized in that the rolling elements (2) as ball rollers each with two symmetrically flattened from a basic spherical shape and arranged parallel to each other side surfaces and the Wälzkörperkanäle (6) as ball roller channels with support areas (8), return areas (9) and deflection and a nem designed as ball rolling elements (2) adapted

Cross-sectional profile are formed.

2. Linear guide according to claim 1, characterized in that the inner guide part (3, 3 ') as a profile rail and the outer guide part (4, 4') as a profile rail (3, 3 ') encompassing supporting body is formed, together form a profiled rail guide (1, 1 ', 1 "), wherein the roller bodies designed as ball rollers (2) in trained as a ball roller rows Wälzkörperreihen (5) in two laterally of the inner guide part (3, 3') formed in the longitudinal direction O Circularly running, cross-aligned and deflected at the end, trained as ball roller channels rolling element channels (6) circulate, and that designed as ball roller channels rolling element channels (6) so- as accordingly the orientation of the axes of rotation of the rolling elements (2) designed as ball rollers are inclined by 45 ° with respect to a vertical axis (7) of the inner guide part (3, 3 ').

3. Linear guide according to claim 1 or 2, characterized in that at least their axial width is reduced at least approximately corresponding to the reduced relative to the ball base axial length of the rolling elements designed as ball rolling elements (2).

4. Linear guide according to at least one of claims 1 to 3, characterized in that the Wälzkörperlaufbahnen (10, 10 ', 11, 11') formed as ball roller channels Wälzkörperkanäle (6) at least in the support areas (8) have a hardened surface.

5. Linear guide according to at least one of claims 1 to 4, characterized in that the inner guide part (3 ') and / or the outer guide part (4') is made of a lightweight material.

6. Linear guide according to claim 5, characterized in that the inner guide part (3 ') and / or the outer guide part (4') is designed as an aluminum extruded profile.

7. Linear guide according to claim 5 or 6, characterized in that in the support areas made of a lightweight material (8) projecting wires (14, 15) inserted into recesses provided and as Wälzkörperlaufbahnen (10 ', 11') for as ball rollers trained rolling elements (2) are formed.

8. Linear guide according to claim 7, characterized in that the profile wires (14, 15) as hardened steel profile wires or work-hardened

Profile wires are formed of stainless steel.

9. Linear guide according to at least one of claims 1 to 8, characterized in that the return areas (9) of the roller body channels (6) designed as ball roller channels are designed as bores in the outer guide part (4, 4 ').

10. Linear guide according to at least one of claims 1 to 9, characterized in that the return areas (9) designed as ball roller channels Wälzkörperkanäle (6) adapted to the cross-sectional profile of the rolling elements designed as ball rollers (2), in a plastic injection molding or by direct injection molding manufactured plastic liners (12).

11. Linear guide according to at least one of claims 1 to 10, characterized in that the deflection regions of the roller body channels (6) designed as ball roller channels are designed as plastic parts molded onto the end faces of the outer guide part (4, 4 ').

12. Linear guide according to at least one of claims 1 to 11, characterized in that the deflection of the ball roller channels designed as rolling element channels (6) by means of caps are lockable to the outside.