Play-free plain bearing and use of a play compensation element for producing a play-free plain bearing

Abstract

The present invention relates to a play-free plain bearing having a first part (1) and a second part (2), wherein one of the two parts (1, 2) is stationary and the other part (2, 1) moves with respect thereto, wherein the first part (1) has a base element (3) and a first sliding surface (4), and the second part (2) has a second sliding surface (5), wherein the first sliding surface (4) and the second sliding surface (5) are in contact with one another, wherein a play compensation element (6) which comprises a compressed viscoelastic foam (6) is arranged between the base element (3) and the first sliding surface (4). The invention also relates to the use of a play compensation element (6) between a first part (1) and a second part (2), wherein one of the two parts (1, 2) is stationary and the other part (2, 1) moves with respect thereto, for producing a play-free plain bearing, wherein the play compensation element (6) comprises a compressed (15) viscoelastic foam (6), in particular is a compressed viscoelastic foam (6).

Description

[0001] Free-play sliding bearing and use of a play-compensating element to create a free-play sliding bearing

[0002] The present invention relates to a backlash-free plain bearing with two parts movable relative to each other, which, during their movement relative to each other, are pressed against each other by means of a backlash compensation element such that movement is still possible, but there is no play in the direction of the contact force. The invention also relates to the use of a backlash compensation element between a stationary first part and a movable second part to produce a backlash-free plain bearing.

[0003] For example, sliding guides for translational and rotational movements are known in sprung seats. Non-ball-bearing roller guides are also referred to as sliding guides within the scope of this invention, since sliding friction occurs on the inner wall of the roller against a roller journal, or on the end face of the roller, either internally against the roller journal or externally against a contact surface. Such sliding guides are regularly subject to requirements regarding both smooth operation and high rigidity. Particularly in ferry operations with intensive movements of the vehicle floor, high dynamic rigidity of the seat, and thus also of the guide systems installed within it, is required.Such guideways often consist of numerous or complex components, so that geometric variations occur in these guideways due to the cumulative effect of dimensional tolerances of the individual components (tolerance chains) or due to complexly formed components (for example, those manufactured by stamping and bending processes). If these tolerances result in a spatial overlap of components, high normal forces are generated within the components, leading to significantly increased friction. If the tolerances run in the opposite direction, play develops in the guideways, resulting in unwanted noise or accelerated wear. Avoiding tolerance overlaps while simultaneously preventing disruptive play in a guideway requires very precise manufacturing of all components, which is regularly associated with high costs.The obvious solution is to design the components forming the guide, which are intended to move relative to each other, with elasticity, so that with a deliberately engineered tolerance overlap, the spring travel of the components can compensate for this excess. However, this generally represents only an inadequate compromise, because with high elasticity (low spring stiffness) either the stiffness of the guide no longer meets the requirements, or with low elasticity (high spring stiffness) the friction in the sliding guide becomes too high. Solutions in which the free play between individual components of the guide is eliminated by means of inserted springs represent only a variation of the elasticity solution described above. Within the spring's range of motion, which is intended to compensate for manufacturing tolerances, the following compromise still exists: If the spring force is low, only insufficient dynamic strength is achieved.If a high spring stiffness is chosen, high frictional forces occur, which impair the smooth running of the guide.

[0004] The object of the invention is to present a backlash-free sliding bearing that avoids the aforementioned problems.

[0005] The object is achieved according to the invention by a backlash-free plain bearing having the features of one of claims 1, 9 or 10. The object is also achieved by the use of a backlash compensation element in a backlash-free plain bearing having the features of claim 12. Advantageous embodiments are specified in the dependent claims.

[0006] The problem is then solved by a backlash-free sliding bearing according to claim 1, in which, instead of the previously known spring, a compressed viscoelastic foam is present between the stationary (e.g., first) part and the movable (e.g., second) part of the sliding bearing, pressing the first sliding surface against the second sliding surface without play. For the purposes of this patent application, a viscoelastic foam is understood to be a foam that exhibits high stiffness under dynamic load and can otherwise be compressed like a soft spring. TEMPUR® is, for example, such a foam according to the invention. For the sake of simplicity, the term "foam" will henceforth refer only to a viscoelastic foam according to the invention. During assembly, the foam can be compressed like a relatively soft spring, thus eliminating free play in the sliding bearing.Furthermore, the foam has the property of exhibiting very low restoring force, thus keeping friction in the plain bearing low. Due to the foam's very high stiffness under dynamic load, the plain bearing retains its high dynamic strength. Incorporating the foam according to the invention provides a cost-effective solution for a backlash-free and simultaneously dynamically stiff plain bearing. This allows the plain bearing to be designed cost-effectively with coarser manufacturing tolerances for the individual components. The backlash compensation element made of the foam according to the invention is dimensioned so that, even with minimal installation space, it is not fully compressed within the tolerances, thus preventing the restoring force from significantly increasing friction in the plain bearing. In principle, this principle can always be applied when cost-effective backlash elimination in a plain bearing is desired.For the purposes of this application, a sliding bearing is also understood to be a bearing that uses a roller as a bearing element, since sliding movement also takes place under real conditions.

[0007] An advantageous embodiment of the invention provides that the first sliding surface is formed on a flexible film, which is in particular designed as a laminated foam part with a wear-free sliding layer, and which is connected to the base element in a connection area. This allows the advantages of the invention to be achieved even in sliding bearings that do not have additional parts, such as separate fastening means for attaching the first sliding surface to the base element, and are designed to be very thin.

[0008] A further advantageous embodiment of the invention provides that the first sliding surface is formed on a rigid sliding body, in particular a plate made of a material with low frictional resistance to the contact surface, such as polyamide, PTFE (for example, Teflon®) or Iglidur®, which is connected to a slider housing attached to the base element. This allows the advantages of the invention to be achieved even with sliding bearings that have a slider housing, especially when the slider housing includes a bearing plate with a recess in which the backlash compensation element is arranged.

[0009] Preferably, the connection of the flexible film to the base element in the connection area and / or the connection of the slider housing to the base element is carried out by means of gluing, screwing, riveting or welding.

[0010] A further advantageous embodiment of the invention provides that the basic element comprises a bearing element in which a sliding body is arranged, on which the first sliding surface is formed, and the second part comprises a U-profile, wherein the second sliding surface is formed on one of the two free legs of the U-profile. This opens up further fields for the sliding bearings according to the invention, such as the guides of height-adjustable vehicle seats with scissor linkages.

[0011] A further advantageous embodiment of the invention provides that the base element is mounted on a roller journal of a transverse tube, and a roller is rotatably attached to the roller journal, its running surface being in contact with the other of the two free legs of the U-profile. This reduces the friction between the two parts of the sliding bearing.

[0012] A further advantageous embodiment of the invention provides that the base element comprises a bearing element in which an additional roller holder is arranged, in which an additional roller is mounted, the running surface of which forms the first sliding surface, and the second part comprises a U-profile, wherein the second sliding surface is formed on one of the two free legs of the U-profile, and the play compensation element is arranged between the base element and the additional roller holder. This is particularly advantageous in guides for height-adjustable vehicle seats with scissor linkages, as it reduces friction in such sliding bearings.

[0013] The problem is also solved by a backlash-free plain bearing according to claim 9. The compressed foam presses the contact surface of the roller, facing away from the roller journal, against a guide rail, which is designed in particular as a U-profile, thus achieving backlash-free operation in the plain bearing. Such plain bearings are used especially in guides for height-adjustable vehicle seats with scissor linkages.

[0014] Furthermore, the problem is also solved by a backlash-free sliding bearing according to claim 10. The compressed foam presses the end face of a roller journal, on which a roller is rotatably mounted, against a guide rail, which is designed in particular as a U-profile, so that backlash-free sliding bearings are achieved between the end face of the roller journal and the roller. The difference between this embodiment and an embodiment according to the preceding paragraph is the location where the claimed sliding bearing is formed (either between the roller and the guide rail or between the roller journal and the roller). Such sliding bearings are also used for the aforementioned guides of height-adjustable vehicle seats with scissor linkages.

[0015] A further advantageous embodiment of the invention provides that a metal disc is arranged between the end face of the roller journal and the roller or the sliding area of ​​the guide rail. This reduces the end-face friction between the foam and the roller journal.

[0016] The problem is also solved by using a backlash-compensating element in the form of a foam in a backlash-free sliding bearing with the features of claim 12. This achieves the advantages stated above for the sliding bearings according to the invention. In particular, the backlash-free sliding bearing is designed according to any one of claims 1 to 11.

[0017] Further details and advantages of the invention will now be explained in more detail with reference to exemplary embodiments illustrated in the drawings. These show:

[0018] Fig. 1 shows a schematic section through a first embodiment of a sliding bearing according to the invention with a slider housing,

[0019] Fig. 2 shows a schematic section through a second embodiment of a sliding bearing according to the invention with a foil-shaped first sliding surface which is attached to a base element by separate fastening means,

[0020] Fig. 3 shows a schematic section through a third embodiment of a sliding bearing according to the invention with a foil-shaped first sliding surface which is bonded to the base element,

[0021] Fig. 4a-4b Top view and section through a fourth embodiment of an embodiment according to the invention, in which the foam is arranged in a recess of a bearing plate,

[0022] Figs. 5a-5b show a fifth embodiment of a sliding bearing according to the invention with a sliding block and a roller from different directions and in different assembly states.

[0023] Fig. 6a-c shows a sixth embodiment of a sliding bearing according to the invention with a sliding block and several rollers from two directions (one with a guide rail) and a cross-section,

[0024] Fig. 7 shows a schematic section through a seventh embodiment of a sliding bearing according to the invention with a roller. Fig. 1 schematically shows a section through a first embodiment of a sliding bearing according to the invention, where the elements with reference numerals 3, 9, and 10 are not hatched, although they each represent a sectioned surface. The sliding bearing has a stationary first part 1 and a movable second part 2. The movement can be either translational—for example, perpendicular to the plane of the blade—or rotational about a vertical axis.

[0025] The first part 1 has a base element 3 in the form of a plate 3. A slider housing 8 is attached to this plate 3 by means of a housing fastening 9 – which can be, for example, screws or rivets. A sliding element 7 is movably mounted in the slider housing 8 and can perform a vertical relative movement with respect to the base plate 3. A foam 6 according to the invention (as described above, this foam is viscoelastic, but this detail will be omitted hereafter for the sake of simplicity) is arranged between the sliding element 7 and the base plate 3. On the side facing the second part 2, the sliding element 7 has a first sliding surface 4.

[0026] The second part 2 has a rotating plate 10 which has a second sliding surface 5 on its side facing the first part 1, which is in contact with the first sliding surface 4 of the first part 1.

[0027] The thickness of the foam 6 is selected such that, when the rotary plate 10 is mounted relative to the base plate 3, the foam 6 is compressed in the vertical direction. In this state, the foam 6 is still compressible. Due to the viscoelastic properties of the foam 6, the sliding bearing exhibits very high stiffness under dynamic loads—that is, under an abrupt vertical force application to the sliding bearing—but is compressible like a soft spring under quasi-static loads, such as during assembly. This eliminates the vertical play of the sliding bearing in the static state, while the sliding bearing retains its high dynamic strength in the dynamic state. The second embodiment of a sliding bearing according to the invention, shown schematically in section in Fig. 2, differs from that shown in Fig.The first embodiment shown in Figure 1 differs only in two points (where the elements with reference numerals 3, 9, 10 and 11 are not hatched, although they are cut surfaces). Firstly, the rigid sliding body 7 is replaced by a flexible film 11, and secondly, this film 11 is directly connected to the base element 3 without the interposition of a sliding housing 8. The same means are used as shown in Figure 1 for attaching the film 9.

[0028] Suitable materials for housing fastening 9 include screws and rivets. Laminated foam components are particularly suitable as flexible film 11, providing a wear-free sliding surface in the area of ​​the first sliding surface 4. During assembly of the sliding bearing, the flexible film 11 is bulged and stressed in the area where the foam 6 is present, thus eliminating any vertical play between the first part 1 and the second part.

[0029] 2 is present. As shown in Fig. 1, the foam 6 is compressed in the assembled state, so that the sliding bearing has the same properties as described above for Fig. 1. In contrast to the first embodiment in Fig. 1, no additional component in the form of the slider housing 8 shown there is required, which saves on additional components and simplifies assembly, resulting in a price reduction.

[0030] The third embodiment of a sliding bearing according to the invention, shown in a schematic section in Fig. 3 (where the elements with reference numerals 3, 10, and 11 are not hatched, although each represents a sectioned surface), differs from the second embodiment shown in Fig. 2 only in that the film 11 is attached differently to the base element 3. Instead of using additional separate screws or rivets, the film 11 is bonded to the base element 3 in a section of the film 11 designated as the adhesive area 12. The assembly is otherwise identical to that of the second embodiment, and in contrast, additional components are eliminated. Otherwise, the same advantages and properties are present.

[0031] The fourth embodiment of a sliding bearing according to the invention, shown in Figures 4a and 4b (Figure 4a shows a top view of the first part 1 from above without the inserted sliding element 7 and without the inserted second part 2, while Figure 4b corresponds to the section according to Figure 1, however, the hatching on the elements with reference numerals 3, 7, 10 and 13 has been omitted for better visibility, even though these are cut surfaces – only the foam 6 is hatched), differs from the first embodiment shown in Figure 1 essentially only in one respect. Instead of the sliding element 7 being arranged in a sliding housing 8 as in Figure 1, the sliding element 7 is located in a recess 14 formed in a bearing plate 13, in which the foam 6 is also arranged.The bearing plate 13 is arranged on the base element 3 and connected to it – by connection methods known to those skilled in the art – such that these two parts are fixed in position relative to each other. This results in the same advantages as in the first embodiment, wherein the first sliding surface 4 is located on the upper side of the sliding body 7 and the second sliding surface 5 is located on the underside of the rotary plate 10.

[0032] Figure 5a shows a longitudinal section through a fifth embodiment of a sliding bearing according to the invention, the hatching of the transverse tube 19 and the roller journal 26 of the first part 1 being omitted for clarity. This is a component of a height adjustment mechanism for a vehicle seat. Shown is one end of a transverse tube 19 of a scissor linkage system, which is generally well known to those skilled in the art. At one end of a roller journal 26 of the transverse tube 19, a sliding block 15 is arranged as a base element 3, in which a recess 16 is provided in which a play-compensating element 6 and a sliding body 7 are mounted. The sliding body 7 is designed as a plate, which rests on the play-compensating element 6 with its surface opposite the sliding surface 4, thus forming a play-free bearing point.The outer side of the sliding body 7 forms the first sliding surface 4, the inner side of a U-profile 25, in which the roller journal 26 of the transverse tube 19 moves, forms the second sliding surface 5.

[0033] According to the invention, a sliding block 15 which contains a second such backlash-free bearing point on the opposite side, or a sliding block 15 which contains a further such backlash-free bearing point on the end face 28 (both embodiments are not shown).

[0034] Figure 5b shows an advantageous further development of the fifth embodiment of Figure 5a. In addition to the sliding block 15, the sliding bearing has a roller 18 which is mounted on the same roller journal 26. The sliding block

[0035] In this solution, the basic element 3 (15) has a sliding bearing on one side and, together with the roller 18, which rests against the opposite side of the U-profile 25 – in Fig. 5a, this would be the lower horizontal leg of the U-profile 25 – forms a backlash-free bearing. Lateral support in the U-profile 25 is provided by an end face 29 of the roller 18 on the inside of the U-profile 25, which is only shown in Fig. 5a.

[0036] Alternatively, the roller 18 can be arranged in a free space within the sliding block 15, wherein the roller journal 26 extends through a bore in the roller 18 and projects back into the sliding block 15, and the end face 20 of the roller journal 26 rests against the sliding block 15. Contact with the inside of the U-profile 25 is achieved either by the end face 28 of the sliding block 15 itself, or, in the sliding block 15, a backlash-free bearing according to the invention is arranged on its end face 28 in the direction of the U-profile 25 (not shown).

[0037] The sliding body 7 can also be connected to the sliding block 15 via a film hinge, so that after the foam 6 has been inserted it only fits into the recess.

[0038] 16 must be folded down. This simplifies assembly, as no separate part is required. Instead of arranging the roller 18 at the bottom and the sliding element 7 at the top, the reversed arrangement is also possible.

[0039] Figures 6a-6b show a sixth embodiment of a sliding bearing according to the invention. Figure 6a shows a top view of the end of a transverse tube 19 with the sliding block 15 mounted on it, and Figure 6b shows a section along the plane AA in Figure 6a. Figure 6c shows a perspective view, with the object according to Figure 6a arranged in a U-profile 25. The sixth embodiment differs from the fifth embodiment primarily only in the design of the sliding block 15. The roller 18 is arranged inside the sliding block 15, and the sliding element 7 of the fifth embodiment is replaced by two additional rollers 23 (along with the modifications necessary as a result, which are described in more detail below).

[0040] The additional rollers 23 are each arranged in a receiving opening 24 via an additional roller holder 22 and a needle 30 mounted therein, on which the respective additional roller 23 rotates. Their axes are aligned parallel to the transverse tube 19. A piece of foam 6 is inserted below each of the additional roller holders 22, which pushes the additional roller holders 22 – and thus also the additional rollers 23 – upwards. This compensates for the vertical play in the U-profile 25 (as in the fifth embodiment) when the foam 26 is still compressed even in the installed state, since the first sliding surface 4, formed by the running surfaces of the additional rollers 23, then moves by rolling on the second sliding surface 5 (not shown, but formed by the inner surface of the upper free leg of the U-profile 25) instead of sliding.Compared to the fifth embodiment, the advantage is therefore a reduced friction when the sliding bearing moves in a horizontal direction.

[0041] Figure 7 shows a seventh embodiment of a sliding bearing according to the invention in a schematic section, where the hatching of the transverse tube 19 and the roller journal 26 of the first part 1, as well as a metal disc 17, has been omitted for clarity. In contrast to the fifth and sixth embodiments, the foam is located between the end face of the roller journal 26 and the roller 18, with a metal disc 17 preventing direct contact between the foam 6 and the roller journal 26 in order to avoid damage to the foam 6 during relative rotation of the roller 18 with respect to the roller journal 26. To reduce friction between the end face 20 of the roller journal 26 and the metal disc 17, the end face 20 of the roller journal 26 is advantageously designed as a convex end 21. The outside of the (rotating) roller 18 forms a contact with the inside of the U-profile 25 (see Figure 1).5a) the bearing surfaces 4 and 5. In the situation shown in Fig. 7, the foam 6 is compressed, so that the same effect now occurs in the axial (horizontal) direction as was already described above for the other embodiments in the vertical direction: There is a backlash-free bearing, which also has a very high stiffness in the dynamic state.

[0042] Reference numeral list first part second part basic element first sliding surface, bearing surface second sliding surface, bearing surface clearance compensation element, (viscoelastic) foam sliding body slider housing housing mounting, foil mounting rotary plate (movable element) foil adhesive area bearing plate recess bearing element, sliding block recess metal disc roller cross tube end face of roller journal convex end of roller journal auxiliary roller holder auxiliary roller receiving opening U-profile roller journal projection end face of sliding block end face of roller needle

Claims

Patent claims 1. A backlash-free sliding bearing comprising a first part (1) and a second part (2), wherein one of the two parts (1, 2) is stationary and the other part (2, 1) moves relative to it, wherein the first part (1) has a base element (3) and a first sliding surface (4) and the second part (2) has a second sliding surface (5), wherein the first sliding surface (4) and the second sliding surface (5) are in contact with each other, wherein a backlash compensation element (6) comprising a compressed viscoelastic foam (6) is arranged between the base element (3) and the first sliding surface (4).

2. Backlash-free sliding bearing according to claim 1, wherein the first sliding surface (4) is formed on a flexible film (11), which is in particular designed as a laminated foam part with a wear-free sliding layer, which is connected to the base element (3) in a connection area.

3. Backlash-free sliding bearing according to claim 1, wherein the first sliding surface (4) is formed on a rigid sliding body (7), in particular a plate made of a material with low frictional resistance to the contact surface, such as polyamide, Teflon® or Iglidur®, which is connected via a sliding housing (8) attached to the base element (3).

4. Backlash-free sliding bearing according to claim 3, wherein the slider housing (8) comprises a bearing plate (13) with a recess (14) in which the backlash compensation element (6) is arranged.

5. Backlash-free sliding bearing according to one of claims 2 to 4, wherein the connection of the flexible film (11) with the base element (3) in the connection area and / or the connection of the slider housing (8) with the base element (3) is made by means of bonding, screwing, riveting or welding.

6. Backlash-free sliding bearing according to claim 1, wherein the base element (3) has a bearing element (15) in which a sliding body (7) is arranged, on which the first sliding surface (4) is formed, and the second part (2) has a U-profile (25), wherein the second sliding surface (5) is formed on one of the two free legs of the U-profile (25).

7. Backlash-free sliding bearing according to claim 6, wherein the base element (3) is mounted on a roller journal (26) of the transverse tube (19) and a roller (18) is rotatably attached to the roller journal (26), the roller being in contact with the other of the two free legs of the U-profile (25) with its running surface.

8. Backlash-free sliding bearing according to claim 1, wherein the base element (3) has a bearing element (15) in which an additional roller holder (22) is arranged, in which an additional roller (23) is mounted, the running surface of which forms the first sliding surface (4), and the second part (2) has a U-profile (25), wherein the second sliding surface (5) is formed on one of the two free legs of the U-profile (25), wherein the backlash compensation element (6) is arranged between the base element (3) and the additional roller holder (22).

9. Backlash-free sliding bearing between a contact surface of a roller (18) rotatably mounted on a roller journal (26) and a guide rail, which is in particular designed as a U-profile (25), by means of a backlash compensation element (6) arranged between the end face (20) of the roller journal (26) and the roller (18), wherein the backlash compensation element (6) comprises a compressed viscoelastic foam (6).

10. Backlash-free sliding bearing between an end face (20) of a roller journal (26) on which a roller (18) is rotatably mounted, and a sliding area a guide rail, which is in particular designed as a U-profile (25), wherein the end face (20) is pressed against by means of a play compensation element (6) arranged between the end face (20) of the roller pin (26) and the guide rail, wherein the play compensation element (6) comprises a compressed viscoelastic foam (6).

11. Backlash-free sliding bearing according to claim 9 or 10, wherein a metal disc (17) is arranged between the end face (20) of the roller journal (26) and the roller (18) or the sliding area of ​​the guide rail.

12. Use of a clearance compensating element (6) between a first part (1 ) and a second part (2), wherein one of the two parts (1 , 2) is stationary and the other part (2, 1 ) moves to produce a clearance-free sliding bearing, wherein the clearance compensating element (6) comprises a compressed viscoelastic foam (6), in particular a compressed viscoelastic foam (6).

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