Linear motion guide

Abstract

To provide a carriage for a linear motion guide, for arranging on a rail of the linear motion guide.SOLUTION: A carriage has at least a substantially U-shaped cross-section and has at least one substantially U-shaped base body (15) which is supplemented with plastic components. In each case, in both legs of the U-shape, the carriage is connected to at least one self-supporting rolling body housing which is kept open towards the rail in order to guide as precisely as possible on the rail and nevertheless, it is easily assembled. According to the invention, at least parts of inner and outer boundary surfaces of a return channel (10) and both deflection channels (11) of the rolling body housing in each leg are formed by means of a single body plastic component in both legs of the carriage.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a linear motion guide carriage for arrangement on a rail of a linear motion guide having an essentially U-shaped cross section, which comprises an essentially U-shaped base body, which is supplemented with a plastic component, and on both legs of the U-shape respectively, the carriage comprises self-supporting rolling body housings for the circulation of rolling bodies which each remain open towards the rail.

[0002] This type of linear motion guide is employed in linear guide machine components, which are necessary, for example, for moving the translational axes of machine tools. Here, the guide rail is usually fixed to the base by a screw connection. The carriage, which can also be called a guide carriage, comprises at least one rolling body housing on both legs of its almost entirely U-shaped. The rolling bodies circulate in the latter. In the load section of the rolling body housing, which runs in a straight line and parallel to the longitudinal axis of the guide rail, the rolling bodies located there at the moment are supported both on the carriage and on the side of the guide rail. In this way, both a linear relative movement between the guide rail and the carriage and a load transfer to the rail, in particular of the load acting on the carriage, can occur.

[0003] Linear motion guides are often employed in very dirty environments and under unfavourable conditions, such as high or highly fluctuating temperatures, where high precision is required. For this purpose, a substantial requirement is that the rolling elements are not contaminated, as this would have a detrimental effect on wear and on the guide precision. Inaccuracies in the rolling element housing also have a detrimental effect on wear.

[0004] In addition, linear motion guides are subject to requirements regarding the simplest possible structure and the easiest possible assembly, and the solutions for meeting these requirements are often in conflict with the requirements placed on linear motion guides for precise guidance and smooth running.

[0005] The object of the invention is to specify a method in which the rolling elements of a carriage of a linear motion guide of the type mentioned at the beginning can be guided precisely and yet the carriage can be assembled with the least possible effort.

[0006] According to the invention, the object is achieved in a guide carriage and in a carriage of a linear motion guide of the initially mentioned type by the features characterized in claim 1. In this case, it can be provided that, using only one, in particular one monolithic plastic component for each of the two legs of the carriage, at least a part of the inner and outer boundary surfaces of the return channel and of the inner and outer boundary surfaces of both bend channels, respectively, is formed from one of the rolling body housings in the respective leg.

[0007] Furthermore, the object is achieved by a linear motion guide as claimed in claim 14.

[0008] According to the invention, all the inner and outer boundary surfaces of the return and bend channels of the two rolling element housings in the different legs of the carriage can advantageously be formed in one piece from a single common plastic component. In this way, not only can the movement of components and materials in one respective rolling element housing be reduced, with the attendant risk of rough running and increased wear. In addition, the risk of inaccuracies regarding the mutual alignment of the rolling element housings on both sides of the rail can be reduced.

[0009] In particular, the single and therefore step-free and movement-free seamless construction according to the invention of the transition between the respective return channel and the outer boundary surface, which is loaded by the centrifugal forces and pressures of the curved channel, positively influences both the wear and the smooth running behavior of the carriage.

[0010] Due to the advantageous and preferred method according to the invention, a particularly easy, rapid and nevertheless precise assembly of the carriage according to the invention is obtained. The small number of components necessary for constructing at least one rolling body housing on each side of the guide rail can be assembled particularly quickly and precisely. Due to the monolithic construction, the invention is also particularly suitable for small linear motion guides, the small size of which, resulting from the size of such guides, is inherently particularly difficult to handle and difficult to align with one another for assembly. This difficulty is overcome by combining a large number of other components, which are structurally separated from one another, into a monolithic component.

[0011] The mentioned features and advantages can be further improved in that, in a particularly preferred embodiment, both unitary plastic components of the rolling element housings of the different legs are unitarily connected together.

[0012] In a further preferred embodiment of the invention, all the underside, inner and outer boundary surfaces of the component parts of the rolling element housings on both legs of the carriage can be formed on a single plastic component. In this way, assembly can be further simplified and the assurance of the correct orientation of the individual components of the carriage can be further improved. The load zones of each rolling element housing can be advantageously formed on the other hand on one surface of the base body of the carriage, preferably on the opposite inner surface of the legs of the base body. These surfaces of the load zones are the outer surfaces of the legs of the carriage and the base body and therefore are preferably located on one of the legs of the carriage and not on one of the legs of the carriage.

[0013] Furthermore, it has proven to be particularly advantageous if at least one insert is provided which can be joined in or on the plastic component during the formation of the upper part for the horizontal arrangement of the linear motion guide, i.e. while facing the assembly surface boundary surface of at least one of the rolling body housings. Here, if the insert is preferably formed as a single component, it is preferred to cover or provide the upper limit of the rolling body housing over the entire length of the respective return channel as well as over the entire length of both bending channels. In this embodiment, in order to close the respective rolling body housing, the respective insert or insert component therefore has to be inserted only from above into the single plastic component which thus has at least the inner and outer boundary surfaces of the bending channel and the return channel. A simple and nevertheless precise assembly of the carriage according to the invention can also result from this method.

[0014] In a particularly preferred embodiment of the present invention, the assembly effort can be further reduced in that an insertable insert is formed as a plastic component and the upper boundary surfaces of both flex channels as well as at least one return channel of the circulation channels are formed on this insert.

[0015] Finally, in a particularly preferred embodiment of the invention, if the inserts of the rolling element housings of different legs of the carriage and at least one, preferably two bridge parts connecting both inserts are formed as a single all-insert component, the assembly effort can be further reduced and the orientation accuracy of the components of several rolling element housings of the carriage can be further improved.

[0016] Here, it can be particularly advantageously provided that for two rolling element housings arranged on different legs of the carriage, one insert is provided each for forming an upper boundary surface, and both inserts are connected together in a unitary manner with at least one bridge section. In addition, it can be advantageously provided that in the zone of the upper boundary surface of the bent channel, one bridge section is provided each, which is located on the upper boundary surface and on the rolling element housing and is formed in a unitary manner together with the insert, respectively. By means of this type of method, the insert component can be designed to be lightweight and nevertheless particularly stable. In addition, the bridge parts arranged on the faces of the insert component can be used to form a releasable connection with a unitary plastic component and / or metal substrate, which is preferably inserted between the two bridge parts of the insert component.

[0017] Additional preferred solutions can contribute to a reduction in the assembly effort. In this case, the unitary plastic component is releasably fixed by at least one snap coupling to another component of the carriage or releasably attached to the carriage. Preferably, the unitary plastic component is releasably fixed to at least one snap coupling on both its faces, respectively, snap couplings being preferably provided on both faces with the same component of the carriage. Preferably, the unitary plastic component is fixed to the insert component by at least two snap couplings, the insert component being preferably inserted into the unitary plastic component such that both bridge parts of the insert element are located between the plate-like sections of the unitary plastic component.

[0018] On the other hand, the insert component is preferably fixed to the metal base, which fixing is also preferably formed as at least one snap coupling. A particularly advantageous further development of this solution can be provided in that the insert component is releasably fixed to the base of the carriage in the zones of its two bridge parts with one snap coupling each.

[0019] With respect to the direction seen transversely to the provided longitudinal movement direction, the snap couplings can preferably be arranged centrally in each case. A particularly preferred feature is that all snap couplings between the base body, the insert element and the unitary plastic component are arranged along an axis running parallel to the rail in the operating position of the carriage on the guide rail.

[0020] Further preferred embodiments of the invention emerge from the claims, the description and the drawings. [Brief description of the drawings]

[0021] The invention will be explained in more detail below with reference to the embodiments shown purely diagrammatically in the drawings. [Figure 1] 1 is a perspective view of a preferred embodiment of a linear motion guide according to the present invention having a guide rail and a longitudinally adjustable carriage disposed on the guide rail; FIG. [Diagram 2] FIG. 2 is a plan view of the linear motion guide of FIG. [Diagram 3] FIG. 2 is a side view of the linear motion guide of FIG. [Figure 4] 2 is a cross-sectional view of a carriage of the linear motion guide of FIG. 1, and a side view and a plan view of the linear motion guide. [Diagram 5] FIG. 2 is a longitudinal cross-sectional view of a carriage of the linear motion guide of FIG. 1; [Figure 6] FIG. 2 is an exploded view of the carriage of FIG. 1. [Figure 7]2A and 2B are perspective views of two respective individual components of the carriage of FIG. 1 with the return channel and the flex channel of the rolling element housing developed, as well as a bottom view of one of the two components; [Figure 8] FIG. 8 is a perspective view of the components of FIG. 7 assembled together, as well as the base of the carriage. [Figure 9] 8 is a view according to FIG. 7 from a rotated perspective of the component.

[0022] The linear motion guide 1 is shown in FIG. 1 and comprises a guide rail 2 and a carriage 5 arranged on the guide rail 2 and longitudinally adjustable along the longitudinal axis 3 of the guide rail. The guide rail 2 is fixed to a suitable base by means of a screw connection. As can be seen in FIG. 1, the guide rail 2 has a substantially rectangular cross-sectional shape and is provided on both of its sides with two circulating surfaces 4 for the rolling elements. The two circulating surfaces 4 on each side are arranged at an angle of 90° to each other and provide contact and support for the rolling elements of the carriage 5. The definitions of the angles are cited only as examples, other definitions of angles can also be provided in the context of the present invention.

[0023] The carriage 5, which may also be called a guide carriage, has at least an essentially flat assembly surface 6 on the upper side, which is provided for the accommodation, placement and guided movement on the rails of a load to be moved (not shown). As can be seen in particular in Fig. 4, the carriage 5 has a substantially U-shaped cross section. The illustration in Fig. 1 shows the normal operating mode with the rails arranged on a horizontal plane of the linear motion guide 1, the U-shape being rotated by 180°. In principle, the linear motion guide 1 can be used with any desired spatial orientation of the rails 2.

[0024] The carriage 5 of the exemplary embodiment of the invention shown here comprises one rolling element housing 7 on each of its two legs 5a resulting from a U-shape. Each of the two rolling element housings 7 is filled with balls 8, generally steel balls, as rolling elements circulating in the respective rolling element housing 7 during the movement of the carriage 5 relative to the rail 2 in the longitudinal direction of the rail 2 and thus in the direction of movement of the linear motion guide. The two antisymmetrical but otherwise identically constructed rolling element housings 7 each have one load zone 8 or load section located immediately opposite the running surface 4 of the rail 2 running in a straight line and parallel to the longitudinal axis 3 of the rail. Each rolling element housing 7 is provided with a return channel 10 for the rolling elements, spaced apart parallel to the respective load zone 8. The dimensions of the respective load zones 8 and return channels 10 are identical. The return channel 10 and the load zone 8 of each rolling element housing 7 are connected together at both ends by a bent channel 11. Each of the two bent channels 11 of the rolling element housing 7 has a curved profile and finally runs along a circular arc of approximately 180°. The return channel 10 and the bent channel 11 have a constant cross section over their entire length and are completely enclosed with respect to their cross sections. In the load zone 8, a load surface 14 is formed only on the inside of the respective leg of the carriage 5 that is in contact with the rolling elements, while at the same time resting against the running surface 4 of the rail 2.

[0025] As appears inter alia in Figures 1, 4 and 6, the carriage 5 has a base 15, in particular a metal base. An assembly table with a magnetic surface 6 for placing a load on the carriage 5 is formed on the metal base 15. The base 15 also already has a substantially U-shape of the carriage 5. For this purpose, the two legs of the base 15 are parallel to each other, are far from each other and extend perpendicularly from the assembly table. According to this preferred embodiment of the invention shown here, only the surface of the load zone 8 of the rolling element housing 7 is formed on the base 15 of the two rolling element housings 7. All other channels 10, 11 of the two rolling element housings and their surfaces are formed only on two additional components of the carriage 5, as will be explained in more detail below.

[0026] The face-side zone of the base body 15 is each provided with one centrally located recess 17, into which one detent lug of another component can respectively be placed to form a snap-lock connection, as will be explained further below.

[0027] In the first of these two components, each preferably manufactured using an injection molding method, two webs 20, 21 are provided which run parallel to one another and which run with their longitudinal extension parallel to the longitudinal axis of the rail 2. The two webs 20, 21 of this unitary plastic component 22 are in each case connected together on their face ends by one substantially U-shaped plate-like section 23 of the unitary plastic component 22. The plate-like section 23 has a bridge-like shape and is connected at the lower end with the end zones of the webs 20, 21. The two plate-like sections 23 are oriented parallel to one another and are substantially transverse to the longitudinal extension of the webs 20, 21.

[0028] As can be seen in particular in Figures 6 and 7, a linear upwardly opening groove 24 is formed on the upper side of the web. The cross-sectional shape of each groove 24 corresponds to the substantially upwardly opening semicircular shape in the illustration of Figure 4, which continues on either side of the semicircular end with one straight section each. The two straight sections run parallel to each other and have a distance from each other that corresponds to the diameter of the semicircular shape. The length of the parallel running sections of the cross-sectional shape corresponds at least approximately to the radius of the semicircular shape. This upwardly opening groove 24 is part of the respective return channel 10 of the corresponding rolling body housing 7.

[0029] The additional groove sections, bent towards the rail 2, are connected to the double-sided ends of the upwardly opening groove section of the return channel 10. These additional groove sections are lower zones of the respective bent channels 11 belonging to the same rolling element housing 7. With regard to the cross-sectional shape, the groove zone of the return channel 10 and of all the bent channels 11 are identical. The groove zone of the bent channel 11 thus has as boundary surfaces a lower wall zone 11a as well as an inner wall zone 11b and an outer wall zone 11c of the respective bent channel 11.

[0030] The undersides, as well as the inner and outer wall surfaces or wall zones of the return channels 10 of each of the two bent channels 11 of the two rolling element housings 7, which are completely formed on the unitary plastic component 22, are therefore continuous over their entire length and have a constant cross-sectional shape. The entire underside, outer and inner boundary surfaces of these channels are therefore formed, in particular continuously, on the insert component.

[0031] It can also be seen in figure 6 that the detent lugs 25 of the snap-lug connection are formed on the inside of each of the two plate-like sections 23 in the upper zone. These detent lugs 25 are provided on the inside of both plate-like sections 23 with respect to their longitudinal extension and can be at least slightly elastically bent relative to the plate-like sections 23.

[0032] Finally, in figures 6 and 7, a second component for forming a rolling body housing, hereinafter referred to as insert component 26, is shown. With regard to its external shape, the insert component 26 is constructed essentially similarly to the unitary plastic component 22. The unitary insert component 26, constructed in a similar manner, also has two webs 27, 28 oriented at a fixed distance from each other, which, in their operating position on the carriage 5, are oriented parallel to the webs 20, 21 of the unitary plastic component 22. The webs 27, 28 are unitarily connected together by component sections transverse to the webs 27, 28 and positioned at their face ends, hereinafter referred to as bridge parts 29, 30, respectively. The distance of the bridge parts 29, 30 from each other is smaller than the distance of the plate-like sections 23 from each other. The bridge parts 29, 30 also have at least approximately a U-shape, whereby the insert components, such as the base body and the unitary plastic component, can accommodate the rail 2 between their parallel legs of the U-shape.

[0033] It can be seen from FIG. 4 that the upper boundary surface 32 or wall zone of the return channel 10 is formed on the underside of each of the two webs 27, 28 of the insert component 26. Similarly, the upper boundary surface 33 of the two bent channels 11 of each of the two rolling element housings 7 is formed on the underside of the insert component 26. The respective upper boundary surface 33 of the respective bent channel 11 merges continuously without transition into the respective upper boundary surface 32 of the respective return channel 10 of the same rolling element housing 7. The boundary surfaces 32, 33 of the return channel 10 and of the two bent channels 11 for each of the two rolling element housings 7 are unitary and continuous and have a constant cross-sectional shape. Thus, the complete upper boundary surface of the bent channel 10 and the complete upper boundary surface of the return channel 11 are formed on the insert component 26. The return channel and the bent channel are thus free-standing within their respective circumferences.

[0034] Finally, each of the respective bridge parts 29, 30 has its two outer cylindrical bulges 36 located approximately at the level of the webs 27, 28. In each of the bulges 36 a through-bore is additionally provided approximately above the respective web 27, 28. The size, shape and position of the bulges 36 correspond to a concave shape 37 in the inner surface of the unitary plastic component 22. The plate-like sections 23 of the unitary plastic component 22 are each provided with one through-bore in the zone of the concave shape 37.

[0035] It should also be noted in figure 6 that on the inside of each of the two bridge parts 29, 30, detent lugs 40 of the snap coupling are formed in the upper edge zone. These detent lugs 40, which are centrally located on the inside of the two bridge parts 29, 30, can be at least slightly elastically bent relative to the bridge parts.

[0036] 6 and 8, it can be seen that the metal base 15 can then be inserted into the insert component 26 and the insert component 26, in turn, inserted into the unitary plastic component 22. The detent lugs 40 of the insert component 26 now pass into the recesses 17 of the metal base 15. Due to the resilient preload of the detent lugs 40, the insert component 26 is now locked into the base 15 and releasably secured thereby. In other embodiments of the invention, each of the snap or snap-lock connections described herein can be structurally and specifically formed separately.

[0037] Furthermore, the insert component can be inserted into the unitary plastic component. As a result, the webs 27, 28 of the insert component 26 pass through the webs 20, 21 of the unitary plastic component 22, so that the upper boundary surfaces 32, 33 of the webs 27, 28 cover the grooves of the flex channel 11 and the return channel 10 arising from the webs 20, 21, thus complementing these grooves to form the flex channel 11 and the return channel 10. In addition, this insertion movement also causes the detent lugs 23 of the unitary plastic component 22 to pass through the recesses 41 of the insert component on the face side, whereby the insert component 26 and the unitary plastic component 22 are releasably connected together. The rolling elements can flow into the rolling element housing by the mutually aligned recesses of the plastic component 22 and the insert component 26, respectively. With one bracket 42 that can be fixed to the carriage 5 into the receiving grooves 42a per rolling element housing 7, the rolling elements (here balls) are protected from falling out of the load zone 8.

[0038] As an assembly and centering aid, each web 20, 21 has a mating element 46 on its side facing the base. Similarly, each leg of the base is provided with a mating element 45 that matches the mating element of the respective web 20, 21. The two respective mating elements 45, 46 in the assembled carriage 5 are connected in a predetermined manner so that the base and the unitary plastic component are aligned with each other in a predetermined manner. In the illustrated embodiment, the mating element 45 of the base is a concave groove running parallel to the web. The mating element 46 of the plastic component 22 is, conversely, a convex bar whose shape, size and length correspond to the shape, size and length of the groove of the base 15. The bar can thus be placed in an explicitly predetermined position in the groove, thereby resulting in an explicitly predetermined position between the base 15 and the plastic component 22, and thereby also the insert component.

[0039] The recess can be closed by a front plate 43 which can be inserted on both sides of the carriage 5. A wiper can be integrated into the front plate 43 which wipes dirt from the running surface 4 of the rail 2. [Explanation of symbols]

[0040] 1 Linear motion guide 2 Guide rails 3 Longitudinal Axis 4 Running surface 5 Carriage 5a legs 6 Assembly surface 7 Running body housing 8 Load Zones 10 Return Channel 11 Bending Channel 11a Lower Wall Zone 11b Medial wall zone 11c Outer Wall Zone 14 Load Surface 15 Base 17 (in 15) recess 20 (of 22) Web 21 (of 22) Web 22 Single plastic components 23 Plate Section 25 (23) detent lugs 26 Insert Components 27 (of 26) Web 28 (of 26) Web 29 Bridge parts 30 Bridge parts 32 (of 10) upper boundary surface 33 (of 11) Upper Boundary 36 (of 26) bumps 37 (of 22) concave shapes 40 (29, 30) detent lugs 41 (inside 26) recess 42 Bracket 42a Receptor groove 43 Front Plate 45 (15) mating elements 46 (of 22) mating elements

Claims

1. A linear motion guide carriage for placement on a rail of the linear motion guide, comprising: the carriage comprises at least one substantially U-shaped base having at least two legs and at least a substantially U-shaped cross section and supplemented with a plastic component, said carriage comprising at least one free-standing rolling body housing in each of the two legs of said U-shaped base, said rolling body housing remaining open towards said rail, the carriage comprises a unitary plastic component and a plastic insert disposed on the unitary plastic component; the lower, inner, outer boundary surfaces and the flex channel and return channel of the at least one free-standing rolling element housing in each leg of the carriage are formed in the unitary plastic component in each of the two legs of the carriage; the plastic insert comprises two webs connected by a bridge piece, the lower surfaces of the two webs forming an upper boundary surface of the return channel, the lower surface of the bridge piece forming an upper boundary surface of the bent channel of the at least one free-standing rolling element housing; the upper boundary surface of the bent channel merges continuously, without transition, into the upper boundary surface of the return channel of at least one identical free-standing rolling element housing; carriage.

2. 2. The carriage of claim 1, wherein the bridge parts are each formed within a zone of the upper boundary surface of the curved channel, the zone being located on the upper boundary surface and on the two rolling body housings and each formed in one of the webs.

3. 2. The carriage according to claim 1, wherein the at least one free-standing rolling body housing of two different legs of the carriage and at least one of the bridge parts connecting the two webs are formed as a whole unitary insert component.

4. The carriage of claim 3 , wherein said unitary insert component and said unitary plastic component are releasably coupled by at least one snap connection.

5. 4. The carriage of claim 3, wherein said unitary component and said carriage base are releasably coupled by a snap coupling.

6. 2. The carriage according to claim 1, wherein each of the unitary plastic components has at least one connecting part in a zone on the face side of the curved channel, which connects sections of two circulation channels formed in the unitary plastic components in the two legs of the carriage, respectively.

7. The carriage of claim 1 , wherein a single front plate is secured to a substantially flat outer surface of the unitary plastic component by a releasable snap coupling.

8. 2. A carriage according to claim 1, wherein said substantially U-shaped base of said carriage has a surface for a load zone of said at least one free-standing rolling element housing on legs of said base running parallel to each other apart.

9. A linear motion guide for guiding the linear motion of an object, comprising: a rail having one upper surface and two side surfaces; and a carriage as described in claim 1, wherein at least one guide surface is provided on each of the side surfaces, the rail has a substantially U-shaped cross section, and the at least one free-standing rolling element housing is provided in each of the two legs of the U-shape, rolling elements, in particular balls, circulate in a load section connecting the return channel and the bent channel, and the rolling elements located in the load section are stationary on the rail and on the carriage.

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