Spring arrangement for improving air clearance for a partial disc brake

Abstract

Spring arrangement (2) for improving the air clearance of a partial disc brake (1) comprising a brake carrier (3) in which at least two brake pads (4) arranged parallel to each other at a distance are axially displaceable and tangentially rotationally fixed, which can accommodate a brake disc rotatable about an axis of rotation (A) between them, wherein the two brake pads (4) can be brought into engagement with the brake disc by means of a positioning movement, comprising a brake caliper (5) arranged on the brake carrier (3), which at least partially overlaps the brake pads (4) and the brake disc, and is displaceable relative to the brake carrier (3) in the direction of movement of the brake pads (4) by means of an actuating device, wherein the actuating device effects the positioning movement of the brake pads (4), wherein the spring arrangement (2) is suitable and intended to move the brake pads (4) back away from the brake disc after braking,and wherein each spring assembly (2) is supported on the brake carrier by at least one retaining leg for force support such that a spring leg (6) acts elastically on the respective brake pad (4) via a projection to apply the restoring force, directed against the application movement, characterized in that a force support point (15) on the retaining leg (8) of the spring assembly (2), and a force application point (16) on the projection (17) of the spring assembly (2) are each provided on the spring assembly (2) in alignment with each other along a uniform line of force action (18) such that a torque-free restoring force is introduced into the brake pad (4), wherein the spring assembly (2) is provided in a helical winding from a flat sheet material, and wherein the projection (17) and retaining leg (8) are each directed towards the center (19) and bent at an angle α from the spring leg (6).

Description

[0001] A spot-type disc brake with a spring arrangement is known from EP 1 933 054 A1 and EP 0 747 609 B1. The system comprises a brake carrier on which two brake pads arranged at a distance from one another are held, which receive between them a brake disc rotatable about a rotational axis, wherein the two brake pads can be brought into engagement with a friction surface of the brake disc by an advancing movement, comprising a brake caliper arranged displaceably on the brake carrier, which engages over the brake pads and the brake disc, and forms a housing with an actuating device, wherein the actuating device effects the advancing movement of the brake pads, and with at least one spring arrangement which moves the brake pads away from one another again after an advancing movement.The spring arrangement for the two brake pads is designed as a single piece and has a bracket section that overlaps the brake disc and the two brake pads to improve the air gap.

[0002] A spot-type disc brake with a U-shaped retaining clip and spring leg, wherein the retaining leg and spring leg are arranged substantially parallel to a friction surface of the brake disc, is known from WO 2010 / 108830A1.

[0003] The design of conventional spring arrangements requires comparatively high sheet metal volumes for complex three-dimensional forming technology. The spring function also has room for improvement.

[0004] For wear-compensated springing, US 2004 / 0 195 056 A1 describes a pin bearing (pin 24) arranged centrally in a hole of a spring body for the purpose of providing a centrally tilting moment-compensated spring clamping feed for the disc spring clip 24, which is dragged along on the pad side. The disc spring clip lacks a helical coil shape. The still known DE 10 2009 060 204 A1 describes a self-preloaded, closed, defined spring arrangement which provides an elastic spring travel, with a preloaded mount by means of a retaining tongue in a brake carrier, and wherein friction lining wear compensation is provided by displacing the spring arrangement within the guide of the brake carrier after the predetermined elastic spring travel has been exhausted.

[0005] The present invention is therefore based on the object of proposing a favorable spring arrangement which enables low material costs with simplified manufacturing technology while improving brake release behavior and also allows improved spring force introduction.

[0006] This object is achieved according to the invention by the features of patent claim 1. According to the invention, a significant contribution to fuel savings in a motor vehicle is made possible at comparatively low cost. In particular, the force is introduced torque-free, i.e., without disadvantageous tipping tendencies. Furthermore, a simple bending technology is made possible for the production of the spring arrangement, which essentially only comprises bending axes arranged parallel to a main spatial axis. The use of thin sheet steel material is possible. A U-shaped retaining clip is omitted according to the invention. By clamping a section of the spring arrangement between the backing plate and the brake carrier, a separate loss prevention device is omitted. Bending operations around several differently aligned bending axes arranged orthogonally to one another or orthogonally to the three main spatial axes are avoided.This technology essentially provides for a spring arrangement according to the invention to define uniform main bending axes arranged parallel to a main spatial axis, thus eliminating the need for additional, complex bending processes in or around main spatial axes arranged orthogonally or skewably thereto. The preferred embodiment relates to advantageous applications of the invention. Further features and details of the invention will become apparent from the dependent claims together with the description based on the drawings.

[0007] The drawing shows in perspective: Fig. 1; Fig. 1a-c: a spot-type disc brake with spring arrangement according to the prior art WO 2010 / 108830 A1 for explanation, Fig. 2: Inventive spot-type disc brake with spring arrangement in perspective view, Fig. 3: Inventive spot-type disc brake with spring arrangement in perspective view, Fig. 4: Spring arrangement according to the invention in perspective view, Fig. 5: the spring arrangement according to the invention in perspective from a different angle, and Fig. 6: a simplified side view of the spring arrangement according to the invention.

[0008] In the Fig. 1 illustrates a spot-type disc brake 1 with a spring arrangement 2 for improving the air gap according to the prior art WO 2010 / 108830 A1. This comprises a brake carrier 3 on which two brake pads 4 arranged at a distance from one another can be supported. In this context, it is largely irrelevant whether a pulled force support of the brake pads 4 in the brake carrier 3 using so-called hammer heads, or a pushed force support of the brake pads 4, or some kind of mixture of these two methods is provided to absorb the occurring frictional forces or moments. The important thing is that a brake disc (not shown) rotatable about a rotational axis (A) can be provided between the brake pads 4, wherein the two brake pads 4 can be brought into engagement with the brake disc by a feed movement.Furthermore, a brake caliper (floating caliper type) 5 is shown, which is assigned to the brake carrier 3 and at least partially engages over the brake pads 4 and the brake disc. It is provided with a hydraulic, mechanical, or electromechanical actuation device for the brake pads in the direction of movement of the brake pads 4. It is displaceable parallel to the rotational axis A relative to the brake carrier 3, i.e., it is provided in a floating manner, with the actuation device causing the feed movement of the brake pads 4. Mixed forms of these actuation forms, in particular so-called electromechanically / hydraulically actuated combination calipers, preferably for use as an electric parking brake (EPB), are readily conceivable.

[0009] A certain advantage of electromechanically actuated actuators is that at least one directly actuated brake pad (usually a brake pad on a so-called piston or actuator side) can be actively retracted in order to actively adjust its clearance. Using electromechanical actuators therefore generates an advantage in that the residual torque component caused by the directly actuated brake pad can be actively minimized. A spring arrangement 2 is proposed for reducing the residual torque of a brake pad that can be indirectly actuated by housing displacement, particularly on a so-called piston side, or when the actively adjusted clearance component is insufficient.This provides a particularly cost-effective and retrofittable solution by providing at least one separate spring assembly 2 with a separate spring leg 6 and a separate retaining leg 8 for each brake pad 4. The spring leg 6 elastically preloads the respective pad 4 relative to the brake carrier 3 such that, after a feed movement, in other words, after an active brake application, it is moved away from the brake disc again. In principle, each brake pad 4 can also be assigned at least one separate spring assembly 2, but preferably two spring assemblies 2 each.In principle, each of these spring assemblies 2 has at least one substantially U-shaped retaining clip 9 comprising a base section 10 and, at right angles thereto, two legs 11, 12 bent largely at right angles, such that the retaining clip 9 can be clamped force-fittingly directly onto a rail, bead, or the like of the brake carrier 3 by utilizing its spring action. Contours in the form of beveled ramps can be provided on the brake carrier 3 to simplify assembly and generally assist in clipping on and spreading the retaining clip. Advantageously, the said rail or bead can be provided with an undercut into which the retaining clip 9 engages after spreading, such that a predominantly force-fitting holding effect is achieved through positive engagement.For further improved, reinforced fastening, a retaining claw 13 can be provided on the leg 11, 12, which is angled out from a main extension direction of the leg 11, 12 in such a way that a reinforced holding effect on the brake carrier 3 is achieved. In order to securely apply the axially elastic retraction preload force to the brake pad 4 without the spring arrangement 2 shifting in the actuation direction (i.e., in the axial direction A) relative to the brake carrier 3, a retaining leg 8 is provided starting from at least one of the legs 11, 12, which is arranged essentially parallel to a support section of the spring leg 6 and ensures that the spring arrangement 2 is fixed relative to the brake carrier 3. It is understood that the retaining leg 8 and the support section of the spring leg 6 are arranged parallel to the brake disc.

[0010] In the following, the essence of the invention is explained with reference to Fig.2-6 are explained in detail. The spring arrangement 2 is mounted immovably on the brake carrier 3 and for this purpose comprises, at a radially inner end 21, a retaining leg 8 for forming an abutment on the brake carrier 3, and at a radially outer end 22, a projection 17 for engagement with the brake pad 4. Between these two ends 21, 22, a spring leg 6 which is designed as a circular, open bracket made of flat sheet steel material, wound essentially in a helical manner, such that the main bending axes run essentially uniformly parallel to one another and parallel to the associated friction lining carrier plate 28. The spring arrangement 2 is furthermore positioned in the brake carrier 3 without retaining clips, and a loss and rattle protection can be created by force-fitting engagement with the friction lining carrier plate 28.The generation of the restoring force and the introduction of the restoring spring forces onto the components involved are largely torque-free. For this purpose, a force support point 15 on the retaining leg 8 of the spring assembly 2 and a force application point 16 on the projection 17 of the spring assembly 2 are provided, each positioned in alignment with one another as an extension of a uniform force action line 18. Furthermore, the invention is characterized in that the spring leg 6, retaining leg 8, and projection 17 are positioned on the spring assembly 2 in such a way that a force couple is formed that acts on the spring assembly 2 essentially without a lever arm.

[0011] The spring leg 6, at least in its unused, as-delivered state, describes an open circular arc with a center 19 and a given radius 20 such that the force action line 18 extends as a secant through the defined circular arc. An imaginary line connects the center 19 of the circular arc with the force action line 18. This line is arranged orthogonally to the secant, and the length of the line is defined as less than the radius 20 of the circular arc. In one embodiment, the secant can be defined to extend directly through the center 19, so that the length of the line is 0.

[0012] Starting from the spring leg 6, the projection 17 and the holding leg 8 are each arranged so as to be bent at an angle in the direction of the center 19.

[0013] At least one through-hole 23, 24 can be provided on the retaining leg 8 and the spring leg 6, each of which is based on a uniform, commonly aligned bore axis 25. The through-holes 23, 24 formed in this way enable, for example, the axially directed insertion of a dipstick parallel to the rotation axis A for directly measuring friction lining wear. Alternatively, it is possible to insert a tool for fastening to the brake carrier 3 through the through-holes 23, 24. In one embodiment, the bore axes can be provided congruent with the force action line 18 (secant).

[0014] In a widely advantageous embodiment of the invention, for the purpose of favorable positioning between the brake carrier 3 and the spring arrangement 2, it can be provided that the holding leg 8 has a holding bracket 26 at its radially inner end 21, which is bent at an angle β of approximately 90° to the holding leg 7 and engages in a recess of the brake carrier 3.

[0015] The distance T on the projection 17 of the spring arrangement 2 is in the preferred embodiment limited to the thickness T B the associated friction lining carrier plate 28 is provided in a suitably matched manner. For the precise dimensioning and positioning of the projection 17, a cut 27 is machined at the end 22 transversely to the development of the spring arrangement 2, so that the projection 17 formed is bent at an acute angle γ corresponding to the dimension TB transversely to the development. This enables the friction lining carrier plate 28 with its given thickness T Bbetween an edge of the bent projection 17 and an end piece of the circular arc, so to speak, clamped in a force-fitting manner. As a result, this dimensioning of the projection 17 and the friction lining carrier plate 28 advantageously enables different handling and assembly methods. According to a first variant of the invention, this makes it possible for each spring arrangement 2 to be clipped onto the associated friction lining carrier plate 28 for assembly, in order to be inserted into the brake carrier 3 together with the brake pad 4. According to the second variant of the invention, it is possible for each spring arrangement 2 to be inserted into the brake carrier 3 and riveted on before the brake pads 4 are inserted into the brake carrier 3. In this case, the force-fitting clamping between the brake pad 4 and the spring arrangement 2 is only carried out subsequently. The specific selection of the respective variant depends on the requirements of the respective user.

[0016] As the brake disc and friction lining wear progresses, the spring leg 6 is gradually deflected in the axial direction A toward the friction ring of the brake disc and guided into a reset position that differs from the original reset position in the unused, as-delivered condition of the brake. With this progressive wear, the original circular arc shape of the spring leg 6 increasingly transitions into an elongated, ovalized arc that compensates for the friction lining wear. It is understood that, as a result of this stretching / elongation, the spring leg 6 is able to compensate for the amount of wear by adjusting the radius 20 of the circular arc to the permissible amounts of wear. List of reference symbols 1 spot-type disc brake 2 spring arrangement 3 brake carriers 4 brake pad 5 brake caliper 6 spring legs 7 stopping section 8 holding legs 9 retaining clip 10 Base section 11 legs 12 legs 13 Retaining claw 14 Intermediate section 15 Force support point 16 Force application point 17 lead 18 Line of action of force 19 Center 20 radius 21 radial inner end 22 radial outer end 23 Through hole 24 through hole 25 Bore axis 26 support brackets 27 cut 28 Friction lining carrier plate A rotation axis (axial direction) R Radial direction T distance T B Thickness of the lining carrier plate α angle β angle γ angle

Claims

[1] Spring arrangement (2) for improving the air gap for a spot-type disc brake (1), comprising a brake carrier (3) in which at least two brake pads (4) arranged at a distance from one another in parallel are axially displaceably and tangentially non-rotatably supported, which can accommodate a brake disc rotatable about a rotational axis (A) between them, wherein the two brake pads (4) can be brought into engagement with the brake disc by a feed movement, comprising a brake calliper (5) arranged on the brake carrier (3), which at least partially engages over the brake pads (4) and the brake disc, and is displaceable in the direction of movement of the brake pads (4) with an actuating device relative to the brake carrier (3), wherein the actuating device effects the feed movement of the brake pads (4), wherein the spring arrangement (2) is suitable and intended to move the brake pads (4) back from the brake disc after braking,and wherein each spring arrangement (2) is supported by at least one retaining leg on the brake carrier for force support in such a way that a spring leg (6) for restoring force application acts elastically on the respective brake pad (4) via a projection directed counter to the feed movement, , characterized by that a force support point (15) on the holding leg (8) of the spring arrangement (2), as well as a force application point (16) on the projection (17) of the spring arrangement (2), each in extension of a uniform line of action of force (18), are provided on the spring arrangement (2) in such a way that they are aligned with one another, so that a torque-free restoring force introduction into the brake pad (4) is ensured, wherein the spring arrangement (2) is provided from a flat sheet material wound in a helical shape, and wherein the projection (17) and holding leg (8) are each provided in the direction of the center (19) and bent at an angle α from the spring leg (6). [2] Spring arrangement (2) according to claim 1, characterized by that the spring leg (6), holding leg (8) and projection (17) are arranged on the spring arrangement (2) in such a way that a force couple is formed which acts on the spring arrangement (2) essentially without a lever arm. [3] Spring arrangement (2) according to claim 1, characterized by that the spring leg (6) describes an open circular arc with a center (19) and with a given radius (20) such that the line of action of force (18) extends as a secant through the circular arc. [4] Spring arrangement (2) according to claim 1, characterized by that the holding leg (8) is arranged at a radially inner end (21) of the spring leg (6), and that the projection (17) is arranged at a radially outer end (22) of the worm winding of the spring arrangement (2). [5] Spring arrangement (2) according to claim 1, characterized bythat the holding leg (8) and spring leg (6) each have at least one through-bore (23, 24), and that the through-bores (23, 24) have a common, aligned bore axis (25). [6] Spring arrangement (2) according to claim 5, characterized by that the bore axis (25) is congruent with the force action line (18). [7] Spring arrangement (2) according to claim 4, characterized by that the holding leg (8) has a holding bracket (26) for positioning at its radially inner end (21), which is provided bent approximately at an angle β to the holding leg (8) and engages in a recess in the brake carrier (3). [8] Spring arrangement (2) according to claims 1 and 7, characterized by that the angles α, β are each approximately 90°. [9] Spring arrangement (2) according to one or more of the preceding claims, characterized bythat the spring leg (6) of the spring arrangement (2) is successively deflected in the axial direction A towards the friction ring of the brake disc with advancing brake disc and friction lining wear and is guided into a reset position which differs from an original reset position in the unused delivery state of the brake by stretching / elongation, in that with advancing wear the original circular arc shape of the spring leg (6) is increasingly changed into an elongated, ovalized arc, and wherein the spring leg (6) compensates for the amount of wear as a result of this stretching / elongation in that the radius (20) of the circular arc is adapted to the permissible amounts of wear. [10] Part-padded disc brake (1) with spring arrangement (2) for improving the air gap, with the features of the preamble of patent claim 1, characterized bythat a force support point (15) on the holding leg (8) of the spring arrangement (2) and a force application point (16) on the projection (17) of the spring arrangement (2) are each provided in the extension of a uniform force action line (18) in such a way that they are aligned with one another so that a torque-free restoring force introduction into a brake pad (4) is possible, wherein the spring leg (6) of the spring arrangement (2) is successively deflected in the axial direction A towards the friction ring of the brake disc as the brake disc and friction pad wear progresses and is guided into a restoring position which differs from an original restoring position in the unused delivery state of the brake by stretching / elongating it, in that with progressive wear the original circular arc shape of the spring leg (6) is increasingly changed into an elongated, ovalized arc, and wherein the spring leg (6) compensates for the amount of wear as a result of this stretching / elongation,by adjusting the radius (20) of the circular arc to the permissible wear amounts.,

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