Mounting of a lever with a swivel arm opposite a pressure piece

Abstract

A bearing arrangement for a lever (1) provided with a pivot arm (1A) opposite a pressure piece (7), comprising a lever-side, partially cylindrically curved rolling track (45), a pressure-piece-side, partially cylindrically curved rolling track (35), rolling elements (37) rolling on both rolling tracks (45, 35) and grouped in a bearing cage (36), and a bearing shell (80) attached to the lever (1), which is partially cylindrically curved, wherein the outer curvature plane (E) forms the lever-side rolling track (45), characterized in that the bearing shell (80) is provided with bends (81) at its edges, and all bends (81) extend inwards towards the lever (1). that the bearing shell (80) is provided with an opening (50) arranged in or partially extending into the rolling track (45), wherein the opening (50) extends only over a part of the rolling track width, that the bearing cage (36), opposite the stop edge (52) in the circumferential direction, is provided with a projection (53) extending into the opening (50), and that the projection (53) is formed on the bearing cage (36).

Description

[0001] The invention relates to a bearing of a lever provided with a pivoting arm relative to a pressure piece with the features of patent claim 1, as well as to a bearing shell with the features of patent claim 13.

[0002] Bearings with these features are known from DE 10 2005 034 739 A1, DE 10 2007 024 787 A1, and DE 10 2010 006 262 A1. They each consist of an inner and an outer bearing shell, whose circularly curved rolling tracks are radially opposed to each other with rolling elements interposed. Both bearing shells have side walls in the form of chamfers along their longitudinal edges. Since these chamfers overlap or overlap radially, it is necessary that the two bearing shells are precisely aligned with each other in the axial direction.

[0003] The rolling element space located between the rolling tracks, in which the bearing cage with its rolling elements can move, is limited in each of the two circumferential directions by a stop. One of the stops is designed as a projection on the outer bearing shell, and the other as a projection on the inner bearing shell. Both stops or projections protrude into the rolling element space, which proved to be disadvantageous during the assembly of the bearing between a lever equipped with a pivoting arm and a thrust piece.

[0004] Further bearings for a swivel arm are known from DE 199 39 473 A1 and US 5 630 352 A.

[0005] The invention is based on the object of further developing the generic mounting of a lever provided with a pivoting arm relative to a pressure piece in terms of assembly technology.

[0006] To solve this problem, a bearing arrangement with the features of patent claim 1 and a bearing shell with the features of patent claim 13 are proposed. In this bearing arrangement, only the mobility of the bearing cage in one circumferential direction is limited by a projection extending into the rolling element space. In contrast, the mobility of the bearing cage in the other, second circumferential direction is limited without a projection extending into the rolling element space.

[0007] Instead, the bearing shell attached to the lever, on which the lever-side rolling track is formed, is provided with chamfers on its edges, but all of the chamfers extend inward toward the lever. A countersunk stop edge serves as a second stop for the bearing cage, which is a particularly advantageous solution when assembling the bearing between a lever equipped with a pivot arm and a thrust piece. Furthermore, it is not essential for the two bearing shells to be precisely aligned with each other in the axial direction for assembly of the bearing.

[0008] A key feature of the invention is that no element of the lever-side bearing shell protrudes radially outward beyond the rolling track. This has the advantage, among other things, that it is not necessary for the two bearing shells to be precisely aligned with each other in the axial direction for the assembly of the bearing.

[0009] One embodiment proposes that there are bevels on the circumferential edges of the bearing shell, and the bevels secure the bearing shell to the lever. Preferably, the bevels are fastening tabs that engage behind the lever.

[0010] According to the invention, the bearing shell is provided with an opening located in the rolling track or extending partially into it, whereby the opening extends only over a portion of the rolling track width. At the transition to the outer curvature plane, the opening forms a stop edge that limits the mobility of the bearing cage in the circumferential direction.

[0011] With regard to the pressure loads on the rolling element and on the rolling track, it is advantageous if the bearing shell is provided with the opening on a circumferential section remote from the pivot arm of the lever, preferably on the last quarter of the rolling track.

[0012] Preferably, the opening is arranged in the middle of the rolling track width, whereby the width of the opening should not be more than one third of the rolling track width in order to still have sufficient support width available for the rolling elements.

[0013] According to the invention, the bearing cage is provided with a projection extending into the opening, opposite the stop edge in the circumferential direction. This projection is integrally formed on the bearing cage, particularly in the case of a plastic bearing cage.

[0014] Preferably, the circumferential length of the projection formed on the bearing cage is less than the length of the opening. Furthermore, the width of the projection is less than the width of the opening.

[0015] A further embodiment proposes that a pocket of at least the same width as the opening be formed beneath the lever opening. This pocket can be easily manufactured if the lever, including the pivot arm, is formed as a single forged component, and the pocket is also the result of this forging process.

[0016] Further details and advantages are described below with the aid of the drawings. Fig. 1 shows an exploded view of an arrangement for transmitting and amplifying brake force in a compressed air-operated disc brake, comprising a pivotable lever, two rolling bearings, of which only one is shown here, and a pressure piece; Fig. 2a-c a section through the fully assembled arrangement, showing from left to right states of increasing tension; Fig. 3 the cut after Fig. 2b in enlarged scale; Fig. 4 in perspective view components of the bearing of the lever on the pressure piece, wherein the bearing components form an assembly; Fig. 5 an embodiment of a pivotable lever according to the invention, in which bearing shells are attached to the lever, and Fig. 6 in individual representation one of the levers Fig. 5 attached bearing shells.

[0017] The Fig. 1 shows, as a component of a compressed air-operated commercial vehicle disc brake, an arrangement serving to transmit and amplify the brake force, comprising a pivotable lever 1, two roller bearings, of which Fig. 1, only one rolling bearing 2 is shown, and a thrust piece 7. A pressure piston is guided in a brake caliper of the disc brake. When the brake is applied, the pressure piston, after overcoming a clearance, rests against the back of an inner brake pad and presses it against the rotating brake disc of the disc brake. At the same time, the reaction force is transferred backwards via the brake caliper to the other brake pad, which acts from the outside against the brake disc.

[0018] To compensate for brake wear that occurs over time, the disc brake is equipped with an adjustment device. This adjuster is located in an adjusting element with an external thread. This external thread engages an internal thread 6 located in the center of the pressure piece 7, which is designed like a crossbar.

[0019] The friction force between the brake disc and the brake pads, and thus the deceleration of the vehicle, depends on the clamping force generated by a brake cylinder attached to the brake caliper, preferably an air-operated brake cylinder. The brake cylinder, which is described here only by its actuation force F ( Fig. 3) symbolized brake cylinder works against the free end of a swivel arm 1A with which the lever 1 is provided.

[0020] Furthermore, the lever 1, which can also be referred to as a clamping lever, is fork-shaped in that, although there is only one pivot arm 1A, the actual clamping shaft of the lever consists of two axially spaced sections 8A, 8B. Between these two sections 8A, 8B, arranged on the same center line as the pivot arm 1A, there is a free space 9. The free space 9 is an extension of the internal thread 6 formed in the pressure piece 7 for adjustment.

[0021] The rear side of the two-part brake application shaft supports lever 1 against the brake caliper by means of a pivot bearing (not shown). When the brake cylinder is actuated, lever 1 pivots about this pivot bearing toward the brake disc. This pivoting movement, since the rotational axis M of the lever 1 bearing on the thrust piece 7 is arranged eccentrically to the rotational axis M1 of the pivot bearing, causes thrust piece 7 to be advanced toward the brake disc.

[0022] The bearing of the lever 1 on the pressure piece 7 is divided into the two sections 8A, 8B of the clamping shaft. On each side of the A roller bearing 2 is arranged in each of the free space 9 formed in the lever 1 for pivoting the lever 1 relative to the pressure piece 7. For this purpose, the lever 1 is provided with a convexly curved pressure surface 11 on each of the two sections 8A, 8B facing the pressure piece 7. Each pressure surface 11 is partially cylindrical or partially circular with respect to the rotational axis M.

[0023] The opposite pressure piece 7 has two corresponding, concavely curved pressure surfaces 12 in a shell shape. The two pressure surfaces 12 are also partially cylindrical or partially circular with respect to the rotation axis M.

[0024] Between the paired pressure surfaces 11, 12 on lever 1 and pressure piece 7, there is a cup-shaped roller bearing. Its rotational axis M is offset from the rotational axis M1, on which the lever 1 rests at the rear against the brake caliper to absorb the reaction forces. Due to this eccentricity between the two pivoting or rotational axes (M, M1), when the lever 1 is pivoted, the pressure surfaces 11 of the lever 1 are displaced forward toward the pressure piece 7, thus resulting in the desired advance of the pressure piece 7 toward the brake disc.

[0025] Each of the two rolling bearings 2 includes a thrust-piece-side rolling track 35, a lever-side rolling track 45, and a partially circular curved bearing space between them, which accommodates a single bearing cage 36 with rolling elements 37 rotatably mounted therein. The rolling elements 37 are elongated cylindrical rollers that roll along the two rolling tracks 35, 45 and extend essentially across the entire width of the plastic bearing cage 36.

[0026] The thrust-piece-side rolling track 35 is located inside a bearing shell 32, which is attached to the thrust piece 7. At the end of the bearing shell 32 facing the pivot arm 1A, a radial projection 34 is formed on the bearing shell, forming a stop that limits the mobility of the bearing cage 36 in one circumferential direction. The bearing cage 36 with the rolling elements 37 can therefore only move in one circumferential direction until it abuts this projection 34.

[0027] The mobility of the bearing cage 36 is also limited by a stop in the other circumferential direction, namely the direction facing away from the pivot arm 1A. For this purpose, a pocket 50 is located in the lever-side roller track 45, which in the embodiment described here is formed by the pressure surface 11 formed directly on the lever 1 by grinding sections 8A, 8B. The pocket 50 is a material recess in the curved pressure surface 11 and thus in the roller track 45.

[0028] The pocket 50 extends only over a small portion of the total length of the rolling track 45. It also extends only over a portion of the width of the rolling track 45, with rolling track areas remaining on both sides of the pocket 50 for the rolling of rolling elements 37.

[0029] Above all, the pocket 50 forms a stop edge 52 where its wall abuts the partially cylindrical curvature plane E of the rolling track 45. This stop edge 52 forms the second stop, thus limiting the mobility of the bearing cage 36 in the circumferential direction facing away from the pivot arm 1A. The counter-stop to the stop edge 52 is located on the bearing cage 36. For this purpose, a projection 53 is formed on the bearing cage 36, opposite the stop edge 52 in the circumferential direction. The projection 53 projects radially inward far enough that it extends beyond the curved plane E of the rolling track 45 into the pocket 50.

[0030] If the bearing cage 36 is made of plastic, the projection 53 is formed integrally.

[0031] Fig. 3 shows that the length of the projection 53, viewed in the circumferential direction, is significantly less than the length of the pocket 50. The width of the projection 53 is slightly less than the width of the pocket 50.

[0032] The effect of the two stops limiting the mobility of the bearing cage is shown in the Fig. 2a- Fig. 2c. These show the pivot lever 1 in different positions. In Fig. 2a, the swivel lever 1 is in its initial position when the brake is not applied. Fig. 2b shows the lever in a position it assumes when the brake pads come into contact with the brake disc after overcoming the air gap. Fig. 2c shows the lever at maximum tension and full braking force.

[0033] In the normal position of the lever Fig. 2a, the basic positioning of the bearing cage 36 takes place. This is positioned between the two stops, i.e., the projection 34 on the bearing shell 32 on the one hand, and the stop edge 52 on the lever 1 on the other, in such a way that no significant movement of the bearing cage 36 is possible. The further the lever 1 pivots during its actuation, the more the cage moves, and the more the distances to the two stops increase. Therefore, the circumferential length of the projection 53 should be less than the length of the pocket 50 into which the projection 53 is inserted. In the situation according to Fig. 2c, contrary to what is shown, there is no contact between the projection 53 and the wall of the pocket 50.

[0034] The pocket 50 is located on that circumferential section of the lever-side roller track 45 which is furthest away from the swivel arm 1A, in particular on the last quarter of the roller track 45. Because in the Fig. 2c, the rolling elements 37 combined in the bearing cage 36 have moved so far along the lever-side rolling track 45 that none of the rolling elements 37 are located on that longitudinal section of the rolling track 45 on which the pocket 50 is located. At maximum forces, therefore, for all The rolling element 37 also has the full width of the rolling track 45 available for support. At the beginning of the clamping, however, as in Fig. As shown in Figure 2a, some rolling elements 37 are still rolling on the longitudinal section of the rolling track 45 where the pocket 50 is located. Since the pocket occupies the center of the rolling track width, these rolling elements 37 are then only supported on both sides of the pocket 50, not in the center. Due to the low rolling bearing forces in this situation, this is not a disadvantage.

[0035] Since the sole purpose of the pocket 50 is to provide the stop edge 52 for the bearing cage, a small width of the pocket 50 is sufficient. The smaller this width, the more width is available as a contact and rolling surface for the rolling elements 37, which all extend across the full width of the rolling track 54.

[0036] Preferably, the width of the pocket 50 is not more than one third of the contact width of the rolling elements 37 on the rolling track 45.

[0037] In the embodiment described here, the pocket 50 is arranged within the rolling track 45, i.e., the rolling track 45 surrounds the pocket 50 on all sides. Depending on the lever geometry, however, the second stop, which limits the mobility of the bearing cage 36 in the other circumferential direction, can also be realized with a pocket 50 that only partially extends into the rolling track 45 in the circumferential direction. In this case, too, the stop edge is located where the wall of the pocket 50 meets the plane of curvature E in which the rolling track 45 is located.

[0038] The lever 1, including its pivot arm 1A, is a forged component, with the pocket 50 also being the result of the forging process. It is not necessary to subject the pocket 50, and in particular the stop edge 52 formed thereon at the transition to the curvature plane E of the rolling track 45, to additional machining steps, provided the rolling track 45 is machined with high precision, for example, by grinding the forged part in the area of ​​the rolling tracks 45.

[0039] For the fastening of the two bearing shells 32 to the pressure piece 7, each bearing shell 32 is doweled in the pressure piece 7 via an outwardly projecting anchoring pin 60.

[0040] The anchoring pin 60 is of rectangular cross-section with two longer and two shorter sides, and is seated in a substantially rectangular opening of a dowel 61, which in turn is seated in a bore 62 ( Fig. 1) sits in the pressure piece 7.

[0041] The Fig. 4 shows, suitable for each of the two rolling bearings 2, the fully assembled pivot bearing before the final fastening to the trough-shaped Surface 12 of the pressure piece 7. Both pivot bearings are designed identically, therefore accidental interchange is impossible.

[0042] The bearing shell 32 is provided with radially inwardly extending side walls 71, 72 on both longitudinal edges. The bearing cage 36 is located between the side walls 71, 72 and is therefore laterally guided by the side walls 71, 72. On both side walls 71, 72, projections 74 are formed that are wide enough to extend beyond the longitudinal edges 73 of the bearing cage 36, thereby locking the bearing cage 36 radially in the bearing shell 32. The projections 74 represent local material deformations of the edges of the side walls 71, 72.

[0043] For the compactness of the Fig. 4, it is advantageous that the bearing cage 36 is flatter at its two longitudinal edges 73 than in its central region, which combines the rolling elements 37. This design allows for short side walls 71, 72, i.e., side walls 71, 72 with a small radial extension. The side walls 71, 72 are particularly short so that they extend radially less than the cylindrical outer surfaces 37A ( Fig. 4) the rolling elements 37.

[0044] In this way, the side walls 71, 72 do not extend to the curvature plane E of the lever-side roller track 45 when the bearing is fully assembled. The maximum width of the roller track 45 is therefore not subject to any restrictions, which reduces the costs for manufacturing the lever 1. A further advantage is the low requirements for the mutual axial position of the bearing shell 32 on the one hand and the lever-side roller track 45 on the other, which also leads to assembly advantages and low manufacturing costs.

[0045] For a circumferentially inseparable arrangement of bearing shell 32 and bearing cage 36, which is of great advantage during transport and assembly of the bearing, the bearing cage 36 is provided with a locking element 75 on each of its longitudinal edges 73 at its end facing the pivot arm 1A after assembly. The locking element 75 is composed of a circumferentially extending, slender, and therefore laterally resilient section 76, at the end of which is a locking projection 77. A locking lug and an insertion bevel are formed laterally outward on the locking projection, whereby each locking element 75 as a whole has the shape of a spearhead.

[0046] The bearing cage 36 is wider at the locking projections 77 than along its remaining length. If the bearing cage 36 is pushed circumferentially into the bearing shell 32, the locking projections 77 can elastically deflect inward due to contact with the insertion bevels and then slide along the inner sides of the side walls 71, 72. Behind the ends of the side walls 71, 72, the locking projections 77 can spring back due to their arrangement on the flexible sections 76. They project laterally outward, with the locking lugs locking behind the ends of the side walls 71, 72, since their overall width is greater than the internal distance between the two side walls 71, 72.

[0047] A return movement of the bearing cage 36 is then no longer possible. It is secured by means of its two locking elements 75 in the Fig. 4. Bearing shell 32 and bearing cage 36 cannot separate from each other and can therefore be mounted as a unit on the thrust piece 7 without requiring any special care.

[0048] The remaining free movement of the bearing cage 36 is limited by the stop 34 and the stop edges 78 at the ends of the side walls 91, 92. This free movement is dimensioned slightly larger than the maximum rolling movement during braking. Thus, the locking elements 75 are inoperative when the unit consisting of the bearing cage 36 and bearing shell 32 is installed.

[0049] Two lugs 79 formed on the bearing cage 36 are spaced apart by the width of the stop 34, so that during assembly, the bearing cage 36 can be pre-positioned in an initial position relative to the bearing shell 32 via a frictional engagement between the inner sides of the lugs 79 and the outer surfaces of the stop 34. The frictional engagement is so small that it does not represent a disadvantageous hindrance during operation, but is large enough for fixation until installation in the disc brake.

[0050] In the Fig. 5 and Fig. 6 shows another embodiment of the lever 1. As in the first embodiment, the lever 1, including its pivot arm 1A, is a forged component, with the pocket formed in the lever also being the result of the forging process. In the embodiment according to Fig. 5 and Fig.6, however, no grinding of the two rolling tracks 45 is required, since bearing shells 80 made of sheet metal are clipped onto the two relevant sections 8A, 8B. The bearing shells 80 have the same partially cylindrical shape as achieved in the first embodiment by mechanically grinding the lever 1 to produce the rolling tracks 45. The partially cylindrical outer side of each bearing shell 80 therefore forms the curvature plane E and the lever-side rolling track 45.

[0051] The bearing shell 80 is made of deformed and stamped sheet metal. Where the pocket formed in the lever 1 is located behind it, it is provided with an opening 50 arranged in the rolling track 45 or extending partially into the rolling track. The opening 50 extends only over a portion of the rolling track width and, at the transition to the outer curvature plane E, forms the stop edge 52, which limits the mobility of the bearing cage 36 in the circumferential direction. The pocket formed below the opening 50 in the lever 1 is at least as wide and long as the opening 50.

[0052] The bearing shell 80 is provided with bevels 81 on the circumferentially arranged edges. The bevels are in the form of four fastening tabs 81 that engage behind the lever, so that each bearing shell 80 is non-rotatably attached to the clamping section 8A, 8B.

[0053] The two bearing shells 80 are identically designed, so they cannot be confused.

[0054] Each of the two bearing shells 80 is made of a flat sheet metal and has only inwardly beveled portions in the form of the fastening tabs 81. To increase the stability of the bearing shell 80, its sides may be bent, but only inwardly. Radially outward, each bearing shell 80 has no elements protruding beyond the partially cylindrical curvature plane E. The outer side of the bearing shell 80 facing away from the lever 1 is therefore completely flat, apart from its curvature.

[0055] In an alternative embodiment, although the opening 50 is present in the bearing shells 80, there is no pocket behind it. Nevertheless, the desired second limit stop is achieved through the opening 50 if the sheet metal from which the bearing shell 80 is made is of such a material thickness that the projection 53 formed on the bearing cage 36 only penetrates this opening 50 and not into the material of the lever 1. In this case, the stop edge 52 is formed by the transition between the edge of the opening 50 and the curvature plane E of the rolling track defined by the outer side of the bearing shell 80. List of reference symbols 1 lever 1A swivel arm 2 rolling bearings 6 internal threads 7 Pressure piece 8A Section of the clamping shaft 8B Section of the application shaft 9 Free space 11 Printing area 12 printing area 32 bearing shell 34 projection, stop 35 rolling track 36 bearing cage 37 rolling elements 37A Rolling element outer surface 45 rolling track 50 pocket or opening 52 Stop edge 53 lead 60 anchoring pins 61 dowels 62 bore 71 Side wall 72 side wall 73 Longitudinal edge 74 lead 75 locking element 76 flexible section 77 Locking projection 78 Stop edge 79 Nose 80 bearing shell 81 Folded edge, fastening tab E plane of curvature F Force M axis of rotation M1 rotation axis

Claims

[1] Bearing of a lever (1) provided with a pivot arm (1A) relative to a pressure piece (7), with a lever-side, partially cylindrically curved rolling track (45), a pressure piece-side, partially cylindrically curved rolling track (35), rolling elements (37) rolling on both rolling tracks (45, 35) and combined in a bearing cage (36), and with a bearing shell (80) fastened to the lever (1), which is partially cylindrically curved, wherein the outer curvature plane (E) forms the lever-side rolling track (45), characterized by that the bearing shell (80) is provided with bevels (81) at its edges, and all bevels (81) extend inwards towards the lever (1), that the bearing shell (80) is provided with an opening (50) arranged in the rolling track (45) or extending partially into it, wherein the opening (50) extends only over part of the rolling track width, that the bearing cage (36), opposite the stop edge (52) in the circumferential direction, is provided with a projection (53) projecting into the opening (50), and that the projection (53) is formed on the bearing cage (36). [2] Storage according to claim 1, characterized by that no element of the bearing shell (80) projects radially outwards beyond the rolling track (45). [3] Storage according to claim 1 or 2, characterized by that there are folds (81) on the edges of the bearing shell (80) arranged in the circumferential direction, and the folds fix the bearing shell (80) to the lever (1). [4] Storage according to claim 3, characterized by that the folds are fastening tabs (81) that engage behind the lever (1). [5] Storage according to one of the preceding claims, characterized bythat the opening (50) in the transition to the outer curvature plane (E) forms a stop edge (52) which limits the mobility of the bearing cage (36) in a circumferential direction. [6] Storage according to one of the preceding claims, characterized by that the bearing shell (80) is provided with the opening (50) on a circumferential section remote from the pivot arm (1A), preferably on the last quarter of the rolling track (45). [7] Storage according to one of the preceding claims, characterized by that the opening (50) is arranged in the middle of the rolling track width. [8] Storage according to one of the preceding claims, characterized by that the width of the opening (50) is not more than one third of the rolling track width. [9] Storage according to one of the preceding claims, characterized by that in the circumferential direction the length of the projection (53) is less than the length of the opening (50). [10] Storage according to one of the preceding claims, characterized by that the width of the projection (53) is smaller than the width of the opening (50). [11] Storage according to one of the preceding claims, characterized by that a pocket of at least the same width as the width of the opening (50) is formed under the opening (50) in the lever (1). [12] Storage according to claim 11, characterized by that the lever (1) including the pivot arm (1A) is a forged component and that the pocket is the result of the forging process. [13] Bearing shell (80) for supporting a lever provided with a pivoting arm relative to a pressure piece, wherein the bearing shell (80) is partially cylindrically curved and the outer curvature plane (E) forms a lever-side rolling track (45), characterized by , that the bearing shell is provided with folds (81) at its edges, and all folds (81) extend inwards towards the lever (1), that the bearing shell (80) is provided with an opening (50) arranged in the rolling track (45) or extending partially into it, wherein the opening (50) extends only over part of the rolling track width, and wherein the opening (50) is designed such that a bearing cage (36) which is provided with a projection (53) formed on the bearing cage (36) projects into the opening (50) with the projection (53) in the assembled state.

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