Vehicle brake with spindle / nut arrangement and improved lubrication

Abstract

A vehicle brake (10), comprising a housing (12) and a brake piston (20) arranged therein, which acts on a friction member and can be displaced into an actuating position by means of a spindle / nut arrangement (30) coaxial with a central axis (A) of the brake piston (20) and comprising a spindle (32) and a nut (36), in which position it can press the friction member against a rotor of the vehicle brake, wherein the spindle (32) and the nut (36) engage with one another via a thread pair, and an effective length of the spindle / nut arrangement (30) can be extended by a relative rotation occurring between the spindle (32) and the nut (36) in order to transmit a contact force to the brake piston (20), wherein the spindle (32) has a spindle thread (34) designed as an external thread, with at least one solid-state component (74; 78; 82;92) which is in contact with the thread pair and has lubricating properties, wherein the solid component (74; 78; 82; 92) consists of a solid lubricant or contains at least one solid lubricant, characterized in that two pin-shaped solid components (74) are arranged transversely to the central axis (A) and opposite one another and are prestressed in the direction of the spindle thread (34) by a bow spring (76) encompassing the spindle / nut arrangement (30).

Description

[0001] The invention relates generally to vehicle brakes, and more particularly to a vehicle brake of the type comprising a housing and a brake piston disposed therein, which acts on a friction member pressed against a rotor of the vehicle brake for braking. The brake piston exerting the braking force on the friction member can be actuated pneumatically, hydraulically, or electrically, for example, by means of an electric motor.

[0002] In vehicle brakes of the type mentioned, e.g. in hydraulic vehicle disc brakes, a spindle / nut arrangement is often used to enable the brake to be used as a parking brake in addition to normal service braking. For this purpose, the spindle / nut arrangement is generally arranged coaxially to a central axis of the brake piston and is designed to move the brake piston into an actuated position in which it presses the friction member against a rotor of the vehicle brake and thus prevents rotation of the rotor (locking function). A spindle and a nut of the spindle / nut arrangement engage with one another via a thread pair, so that an effective length of the spindle / nut arrangement can be extended by relative rotation between the spindle and the nut in order to transmit a contact force to the brake piston.

[0003] The spindle / nut assembly can be actuated manually, for example, by pivoting a so-called handbrake lever in a vehicle. The pivoting movement is transmitted via Bowden cables to the vehicle brake, where it actuates, for example, a ball-ramp assembly upstream of the spindle / nut assembly. This ball-ramp assembly converts a rotary movement into a lifting movement, which is transmitted to the spindle / nut assembly and thereby moves the brake piston into the actuated position. In such a mechanically actuated parking brake assembly of a vehicle brake, the spindle / nut assembly serves not only to transmit an actuating force to the brake piston, but also to compensate for friction lining wear resulting from use of the vehicle brake.Over time, a friction lining arranged on the friction element becomes thinner due to abrasion, which is compensated for by a corresponding increase in the effective length of the spindle / nut arrangement (adjustment function to compensate for friction lining wear).

[0004] Recently, the parking brake of a vehicle, in particular of a motor vehicle, is increasingly being actuated by means of an electric motor (so-called EPB = electric parking brake), whereby either the spindle or the nut of the spindle / nut arrangement is secured against rotation and by rotation of the other component, nut or spindle, is moved translationally towards or away from the brake piston, depending on the direction of rotation, in order to switch the parking function on or off.

[0005] The problem with vehicle brakes with this type of spindle / nut arrangement is that with increasing service life, mechanical efficiency deteriorates due to an increase in the system's inherent friction. With a mechanically actuated parking brake, this results in the user having to travel a greater distance before the parking function is activated. With an electric motor-actuated parking brake, the electric drive is subjected to increasingly greater loads; for example, the current consumption of the electric motor may increase.

[0006] From DE 16 30 009 A, a self-adjusting force transmission device for a vehicle brake is known, in which a screw thread of a spindle / nut arrangement has different friction coefficients on different flanks of the screw thread.

[0007] DE 10 2009 012 235 A1 discloses a vehicle brake that can be actuated hydraulically and electromechanically and has a spindle / nut arrangement, wherein the spindle forces are transmitted to the nut via several rolling elements. The rolling elements are guided in a rolling element cage.

[0008] DE 41 18 189 A1 describes a ball-bearing spindle device in which lubricant is distributed by means of a pressure source.

[0009] JP S63 - 1 852 A discloses a spindle / nut arrangement with a ball circuit, wherein lubrication is provided in a ball return of the circuit.

[0010] Based on the above-mentioned problem, the invention is based on the object of providing an improved vehicle brake with a spindle / nut arrangement whose mechanical efficiency does not noticeably deteriorate over the entire service life of the vehicle brake.

[0011] This object is achieved by the subject matter of claim 1. Preferred embodiments are specified in the subclaims. In a vehicle brake of the type mentioned at the outset, at least one solid-state component positioned in the spindle / nut arrangement is in contact with the thread pair and has lubricating properties. Such preferably permanent contact of the lubricating solid-state component with the thread pair, i.e. with a thread of the spindle and / or a thread of the nut of the spindle / nut arrangement, prevents the frictional resistance of the thread pair from becoming increasingly greater over time. Until now, only the limited lubricating effect of the brake fluid served to reduce internal friction.Only the lubricating solid-state component of the vehicle brake according to the invention can, through preferably constant contact with the force-transmitting points of the spindle / nut arrangement, repeatedly apply lubricating substances specifically to the force-transmitting points and thus ensure a permanent reduction in friction.

[0012] According to one embodiment, the solid-state component consists of a solid lubricant such as graphite, polytetrafluoroethylene, or similar. Through contact with the thread pair, the lubricating effect of the solid-state component can be maintained until the solid-state component is completely worn out, i.e., no longer exists. By appropriately dimensioning the solid-state component, lifetime lubrication can be achieved.

[0013] According to a modified embodiment, the solid-state component contains at least one lubricant such as molybdenum disulfide, graphite, polytetrafluoroethylene, or the like, which is released to the points to be lubricated through contact of the solid-state component with the thread pair. In such an embodiment, the solid-state component can consist of a carrier material that is not itself lubricating, but has the ability to absorb one or more desired lubricants and release them again over a long period of time. The solid-state component can thus function similarly to a sponge impregnated with a desired lubricant.

[0014] According to the invention, the solid-state component has, for example, the shape of a pin that is arranged at least substantially transversely, i.e., radially, to the center axis of the spindle / nut arrangement. Such a pin-shaped solid-state component can be slidably arranged in a bore of the spindle / nut arrangement that is open to a spindle thread of the thread pairing, in order to be able to repeatedly come into contact with the spindle thread to be lubricated as wear increases. For this latter purpose, a pin-shaped solid-state component can be elastically preloaded toward the spindle thread in order to be essentially constantly engaged with the spindle thread in a lubricating manner.If required, several pin-shaped solid-state components can be used, for example two opposing pin-shaped solid-state components which, according to one embodiment, can be elastically preloaded in the direction of the spindle thread by a common bow spring encompassing the spindle / nut arrangement.

[0015] To fundamentally reduce friction, it is known to design the thread pairing of a spindle nut arrangement as a ball thread pairing, i.e. to arrange balls between the spindle thread and the nut thread. If the thread pairing is such a ball thread pairing, the solid component can be formed by at least one ball of the ball thread. Possible options include balls made of graphite or polytetrafluoroethylene, which are arranged between the other balls of the ball thread, which are usually made of steel and which continually act as a lubricant as they roll in the ball thread pairing. Since only rolling friction occurs on the balls in a ball screw, wear on such spherical lubricating solid components is low and their service life is therefore sufficiently long.

[0016] In other preferred embodiments of the vehicle brake according to the invention, the lubricating solid-state component has a main direction of extension that runs along or parallel to the center axis of the spindle / nut arrangement. In such embodiments, the solid-state component can, for example, have the shape of a ring or a sleeve, wherein the ring or sleeve surrounds a spindle thread of the thread pair of the spindle / nut arrangement over part of its longitudinal extent. Such a ring- or sleeve-shaped solid-state component can be elastic and have an inner diameter that is smaller than a corresponding outer diameter of the spindle thread. During assembly of the spindle / nut arrangement, the elastic solid-state component is then elastically deformed, i.e.its inner diameter is widened, which on the one hand ensures good contact with the spindle thread to be lubricated and on the other hand compensates for wear on the solid component due to the elastic preload towards the spindle thread.

[0017] In another aspect of the invention with a ring- or sleeve-shaped solid-state component, the solid-state component can be rigid, and an inner diameter of the solid-state component can be slightly larger than a corresponding outer diameter of the spindle thread. This allows for assembly of the spindle / nut assembly with little force, while still ensuring good lubrication of the spindle thread, since during operation of the spindle / nut assembly, the nut and spindle tilt slightly relative to each other, causing the spindle thread to repeatedly come into lubricating contact with the solid-state component.

[0018] In yet other embodiments of the vehicle brake, the solid-state component is strip-shaped and held in a longitudinal groove of the spindle or nut. A plurality of longitudinal grooves can be formed on the spindle or nut, so that a plurality of strip-shaped solid-state components are each mounted in an associated longitudinal groove on the spindle or nut. If the spindle and nut each have at least one longitudinal groove, strip-shaped solid-state components can be mounted on the spindle and nut. Preferably, the or each strip-shaped solid-state component extends over the entire length of the spindle or nut thread. The or each strip-shaped solid-state component can be designed to be elastic with an oversize or rigid, as described above in connection with ring- or sleeve-shaped solid-state components.

[0019] According to a further development of embodiments with a strip-shaped solid component, the number of longitudinal grooves in the spindle thread or nut thread is greater than the number of strip-shaped solid components. At least one longitudinal groove thus remains free and can serve as a vent channel connecting the interior of the spindle / nut assembly with the outside environment, which is particularly important when changing the brake fluid. Previously required vent holes in the spindle / nut assembly for this purpose can thus be eliminated. Free longitudinal grooves serving as vent channels can be provided either in the spindle thread or the nut thread, or in both threads.

[0020] To further improve the venting capability of a vehicle brake, an annular flange of the spindle / nut assembly intended to engage the brake piston can have at least one notch on its outer circumference, which connects the regions of the spindle / nut assembly located axially on either side of the annular flange in a fluid-conducting manner. The at least one notch can be stamped or formed during the manufacture of the annular flange and prevents a closed chamber from forming between the brake piston and the spindle / nut assembly when the annular flange engages the brake piston.

[0021] The previously described embodiments with free longitudinal grooves in the spindle and / or nut thread of the spindle / nut arrangement and at least one notch in the annular flange of the spindle / nut arrangement can be used to improve the venting of a vehicle brake with a spindle / nut arrangement even without a lubricating solid component.

[0022] In embodiments of the vehicle brake with a nut thread that has a plurality of parallel longitudinal grooves distributed over the circumference of the nut thread and extending over the entire length of the nut thread, the nut can have an outer diameter in regions provided with the nut thread on its inner side that is reduced by rolling in the longitudinal direction compared to the outer diameter that the nut has in the remaining regions. Such a configuration is advantageous in that the inner diameter of a raw nut component can be reduced by rolling in the longitudinal direction from the outside in those regions that are later to bear the nut thread. The desired nut thread can then be rolled onto these regions, which are still threadless after rolling, by inserting a thread rolling tool into the nut.This avoids the need for machining the nut, which could potentially result in disruptive residues. This design can also be used regardless of the presence of one or more lubricating solid components.

[0023] Several exemplary embodiments of a vehicle brake are explained in more detail below using the attached schematic figures. It shows: Fig. 1 a cross-section through a prior art hydraulically actuated vehicle brake designed as a disc brake with an electric motor actuated parking brake, Fig. 2 shows a cross-section of another hydraulically actuated vehicle disc brake known from the prior art with a mechanical parking brake which can be actuated by a ball ramp arrangement, Fig. 3 a longitudinal section through a nut of a spindle / nut arrangement according to a first embodiment of a vehicle brake according to the invention, Fig. 4 a partially sectioned rear view of the spindle nut from Fig. 3, Fig. 5 a longitudinal section through a nut of a spindle / nut arrangement according to a second embodiment of a vehicle brake, Fig. 6 is a plan view of a spindle / nut arrangement according to a third embodiment of a vehicle brake, Fig. 7 a spatial representation of the embodiment according to Fig. 6 spindle used, Fig. 8 is a partially longitudinally sectioned view of a spindle / nut arrangement according to a fourth embodiment of a vehicle brake, Fig. 9 section IX-IX Fig. 8, Fig. 10 a modified spindle nut that can be used in a vehicle brake, and Fig. 11 is a partially broken away, perspective view of a spindle / nut arrangement according to a fifth embodiment of a vehicle brake.

[0024] The Fig. 1 and generally designated 10 is designed here as a floating caliper disc brake, which in a known manner has a housing 12 on which a floating caliper 14 is displaceably mounted, which has a Fig. 2 overlaps the brake disc 16 shown.

[0025] Located in the housing 12 is a hydraulic chamber 18 in which a brake piston 20 is sealingly received and movable along its central longitudinal axis A. To supply the hydraulic chamber 18 with hydraulic fluid, a connection 22 is provided on the outside of the vehicle brake 10. This connection is connected to a brake pressure transducer unit (not shown here), for example, a brake booster / master cylinder unit actuated via a brake pedal. When the brake pressure transducer unit is actuated, the hydraulic fluid in the hydraulic chamber 18 is pressurized, causing the brake piston 20 to move to the left along the axis A to bring friction linings 24, 26 into frictional engagement with the brake disc 16.If the actuation of the brake pressure transducer unit is terminated, hydraulic fluid can flow from the hydraulic chamber 18 back toward the brake pressure transducer unit, causing the brake piston 20 to move back along the axis A to disengage the friction linings 24, 26 from the brake disc. A radially encircling sealing element, designated 28, which seals the brake piston 20 in the hydraulic chamber 18, assists the return of the brake piston 20 by exerting an elastic return force on the brake piston 20 according to the "rollback" principle. The function of the disc brake 10, which is brought about by hydraulic actuation and which has just been described, as well as its further structural design, is well known to those skilled in the art and therefore requires no further explanation.

[0026] In order that the vehicle brake 10 shown can not only fulfill the previously explained function of a hydraulic service brake, but can also be used as a parking or holding brake, a spindle / nut arrangement, generally designated 30, is provided, which has a spindle 32 arranged coaxially to the axis A with a spindle thread 34 designed as an external thread and a substantially sleeve-shaped nut 36, which here consists of two parts 36a, 36b and is provided with a nut thread 38 designed as an internal thread and matching the spindle thread 34.

[0027] As from Fig. 1, the outer diameter of the part 36a increases to a Fig. 1 right end as shown, wherein a radial support surface is formed at the right end, with which the spindle / nut arrangement 30 is rotatably supported on the housing 12 of the vehicle brake 10 via an axial bearing designed here as a needle bearing 40. The central longitudinal axis A of the brake piston 20 is also the central longitudinal axis of the spindle 32 and the parts 36a and 36b of the nut 36. By means of a connection 42, which here has the shape of an internal multi-groove profile, for an external rotary drive, a rotary drive (not shown here) can rotate the spindle nut 36 in both directions of rotation in order to screw the spindle 32 out of the nut 36 or into the nut 36 and thereby change the effective length of the spindle / nut arrangement 30. This works in the Fig. 1, however, only if the spindle 32 is secured against rotation. In the embodiment shown in Fig. In the embodiment shown in Figure 1, this is achieved in that the spindle 32 has a mushroom-shaped spindle head 44, which is provided on its outer circumference with a plurality of radial projections 46 that engage in axial grooves 48 provided on an inner circumferential surface of the hollow cylindrical brake piston 20. Through the interaction of the radial projections 46 with the axial grooves 48, the spindle head 44 is guided axially in the brake piston 20 in a rotationally secure manner.

[0028] The spindle / nut arrangement 30 therefore serves to convert a rotational movement of the spindle nut 36 into a translational movement of the spindle 32 in order to move the brake piston 20 towards the brake disc 16 and to press the friction linings 24, 26 against the brake disc 16 (parking brake function).

[0029] An electric motor (not shown), for example, can be used to rotate the spindle nut 36, which can transmit its rotary movement to the spindle nut 36 by means of an output shaft designed complementarily to the rotary connection 42. When the spindle 32 is unscrewed from the spindle nut 36 by turning the spindle nut 36, an upper side of the spindle head 44 comes into contact with an underside of a base 50 of the brake piston 20 and can then transmit a locking force. To release a vehicle brake 10 that has been locked by increasing the length of the spindle / nut arrangement 30, the spindle nut 36 must be turned in the opposite direction. The spindle 32 then screws back into the nut 36 and the spindle head 44 detaches from the underside of the piston base 50, whereby no more locking force is transmitted to the brake piston 20.

[0030] As already described, during operation of the vehicle brake 10, the hydraulic chamber 18 is filled with hydraulic fluid, the pressure of which ensures that the brake piston 20 is displaced to press the friction linings 24, 26 against the brake disc 16. In order to place the entire cross-sectional area of ​​the brake piston 20 under hydraulic pressure, in the previously described embodiment of the spindle / nut arrangement 30, several radial bores 52 (see Fig. 1) is provided through which the interior of the spindle / nut arrangement 30 can be vented and filled with hydraulic fluid.

[0031] In Fig. 2 is one of the embodiments in Fig. 1 similar floating caliper disc brake for vehicles is shown, which is hydraulically actuated for service braking and is equipped with a mechanical parking brake assembly to implement a parking or holding brake function. In contrast to the electric motor-operated parking brake assembly of the Fig. 1, the parking brake is activated in the embodiment shown in Fig. 2, by means of a ball ramp arrangement 54 which is functionally arranged upstream of the spindle / nut arrangement 30 and which consists of two coaxially arranged, relatively rotatable ball ramp disks 56 and 58, in whose mutually facing surfaces circumferentially extending, trough-like ball ramps 60 are formed, in which balls 62 are mounted. While the ball ramp disk 56 is mounted in a rotationally fixed manner in the housing 12 of the vehicle brake 10, the ball ramp disk 58 can be rotated relative to the ball ramp disk 56 via a shaft 64 connected to it and a lever 66 attached thereto, for example by means of a handbrake lever (not shown) arranged in the interior of a motor vehicle, the pivoting movement of which is transmitted to the lever 66 by Bowden cables.When the ball ramp disc 58 is rotated, the balls 62 run up the ball ramps 60 and thereby spread the two ball ramp discs 56, 58 axially apart, i.e. the rotary movement of the shaft 64 initiated by the lever 66 is converted into an axially directed lifting movement which is transmitted from the ball ramp disc 58 to the spindle / nut arrangement 30. The spindle / nut arrangement 30, which is in contact with the brake piston 20 via a conical surface 68 of its nut 36, presses the friction lining 24 against the brake disc 16 via the brake piston 20 when the parking brake is applied. Due to the reaction forces known to a person skilled in the art which occur in a floating caliper disc brake, the friction lining 26 is then also pressed against the brake disc 16 via the floating caliper 14.

[0032] To ensure that the parking brake continues to function as intended even when the friction linings 24, 26 are wearing down, i.e. becoming thinner, an adjustment device, generally designated 70, is provided, by means of which the effective length of the spindle / nut arrangement 30 can be increased in order to be able to press even thinner friction linings 24, 26 firmly enough against the brake disc 16. The precise function of this adjustment device 70, which is known to those skilled in the art, is described in DE 10 2008 036 618 A1, the disclosure of which is hereby incorporated by reference. It should therefore only be mentioned at this point that the conical surface 68 of the spindle nut 36 temporarily loses contact with the brake piston 20 when the friction linings 24, 26 are wearing down. By means of spring force, it is then ensured that the nut 36 is unscrewed from the spindle 32 until the conical surface 68 comes into contact with the brake piston 20 again.For this purpose, a thread pairing between the spindle 32 and the nut 36 is designed to be #self-locking.

[0033] As already mentioned, the friction of the thread pairing between the spindle 32 and the nut 36 of the spindle / nut arrangement 30 increases over time. In the following, several embodiments of a vehicle brake 10 are explained in which such an increase in friction is permanently prevented.

[0034] In a first, in the Fig. 3 and Fig. In the embodiment shown in Figure 4, two radially extending, opposing bores 72, 73 are provided in the nut 36 in the area of ​​the nut thread 38, open toward the spindle thread (not shown here), in each of which a pin-shaped, here cylindrical, solid component 74 is slidably received. Like all other solid components described below, the solid component 74 has lubricating properties. For this purpose, it can consist of a solid lubricant such as graphite, polytetrafluoroethylene, etc., or it can have a carrier material or a matrix containing at least one lubricant, for example, molybdenum disulfide, graphite, polytetrafluoroethylene, etc.

[0035] When the spindle / nut assembly 30 is assembled, the radially inner end faces of the two pin-shaped solid components 74 are in frictional contact with the spindle thread 34 of the spindle 32, whereby during a relative rotation between the spindle 32 and the nut 36, lubricant is repeatedly transferred from the pin-shaped solid components 74 to the spindle thread 34. In the Fig. 3 and Fig. In the embodiment shown in Figure 4, a bow spring 76 presses against the radially outer end faces of the pin-shaped solid components 74, whereby the solid components 74 are elastically preloaded radially inward and thus toward the spindle thread 34. As the solid components 74 shorten due to gradual abrasion, they continuously advance due to the elastic preload by the bow spring 76, i.e., they are pushed into the bores 72, 73 and are thus always in contact with the spindle thread 34 to be lubricated.

[0036] In Fig. Figure 5 shows a second embodiment of a lubricating solid component 78, the main extension of which, in contrast to the first embodiment, runs along the central axis A and which has a hollow cylindrical, sleeve-like shape. The sleeve-like solid component 78 is arranged in the nut 36 in a portion of its axial extension, which, when the spindle / nut assembly 30 is assembled, is penetrated by the spindle thread 34. The solid component 78 thus surrounds the spindle thread 34 over part of its longitudinal extension.

[0037] As in Fig. 5, an inner diameter of the solid component 78 is smaller than a corresponding outer diameter of the spindle thread 34 interacting with the nut thread 38. Because the solid component 78 shown is made of elastic material, its inner diameter expands radially when the spindle 32 is inserted into the nut 36 and bears against the spindle thread 34 with radial preload. This radial preload ensures that the solid component 78 rests snugly against the spindle thread 34 over a long period of time, thus ensuring long-lasting, good lubrication of the thread pair consisting of the spindle thread 34 and the nut thread 38.

[0038] In a modified embodiment of the sleeve-shaped solid-state component 78 (not shown), the latter is made of a rigid material, and its inner diameter is slightly larger than the corresponding outer diameter of the spindle thread 34. Although in such an embodiment the sleeve-shaped solid-state component 78 does not lie snugly against the spindle thread 34, during operation of the spindle / nut arrangement 30 a relative tilting regularly occurs between the spindle 32 and the nut 36, which results in the spindle thread 34 repeatedly coming into frictional contact with the inside of the solid-state component 78, as a result of which lubricant is repeatedly transferred from the solid-state component 78 to the spindle thread 34.

[0039] The Fig. 6 and Fig. 7 show a third embodiment of a spindle / nut arrangement 30 of a vehicle brake 10 provided with at least one lubricating solid component. In this embodiment, at least one longitudinal groove 80 is recessed in the spindle thread 34 (see Fig. 7), in which a strip-shaped solid-state component 82 is held (see Fig. 6), for example, is trapped. How Fig. 7 shows, the longitudinal groove 80 extends over the entire length of the spindle thread 34, so that during operation of the parking brake, a permanent lubrication of the entire thread pairing takes place. As in the previously described embodiment, the strip-shaped solid component 82 can be made of elastic material with an oversize and is then radially compressed when the spindle 32 and nut 36 are assembled, or it can be made of rigid material with a slight undersize and then comes into lubricating engagement with each relative tilt between the spindle 32 and nut 36. Although not shown, several longitudinal grooves 80 and also several strip-shaped solid components 82 can be present in the spindle / nut arrangement 30. If several longitudinal grooves 80 are recessed in the spindle thread 34 and not all longitudinal grooves 80 are occupied by strip-shaped solid components 82, each free longitudinal groove 80 can advantageously serve as a venting channel, whereby the Fig. 1, radial bores 52 can be omitted.

[0040] The Fig. 8 and Fig. 9 show a fourth embodiment in which, analogous to the third embodiment, one or more longitudinal grooves 84 are recessed in the nut thread 38. The Fig. The cross section through the nut 36 in the area of ​​the nut thread 38 shown in Figure 9 shows five longitudinal grooves 84. As previously explained, not all longitudinal grooves 84 have to be filled with strip-shaped solid components 82, but one or more longitudinal grooves 84 can remain free to serve as ventilation channels.

[0041] On the initially cylindrical outer side of the nut 36, channel-like depressions or regions 85 are formed which are formed by means of a rolling tool by rolling in the longitudinal direction, i.e. essentially parallel to the axis A, at the locations where the regions carrying the nut thread 38 are later to be located inside the nut 36. In other words, the inside diameter of a raw nut component (not shown) is reduced by rolling from the outside in the longitudinal direction in those regions which will later carry the nut thread. The desired nut thread 38 is then rolled onto these regions, which are still threadless after rolling, by inserting a thread rolling tool into the nut 36. Residues from machining are thus avoided.

[0042] The third and fourth embodiments can be combined with each other, ie longitudinal grooves 80 and 84, respectively, and strip-shaped solid components 82 can be present on both the spindle 32 and the nut 36, but this is not necessary to achieve proper lubrication.

[0043] Fig. 10 shows a modified design of the spindle nut 36 from Fig. 8, in which a plurality of notches 88 are formed on the outside of an annular flange 86 intended for engagement with the brake piston 20, for example by stamping. The notches 88 connect the axially adjacent regions of the spindle / nut arrangement 30 to one another in a fluid-conducting manner, thus ensuring good venting of a vehicle brake 10 equipped with such a spindle nut 36.

[0044] Fig.Finally, Figure 11 shows a fifth embodiment of a spindle / nut assembly 30, in which the thread pairing is designed as a ball thread pairing. A plurality of balls 90 are arranged between the spindle thread 34 and the nut thread 38, one or more of which serve as a lubricating solid component.

Claims

[1] Vehicle brake (10), with a housing (12) and a brake piston (20) arranged therein, which acts on a friction member and can be moved into an actuating position by means of a spindle / nut arrangement (30) coaxial with a central axis (A) of the brake piston (20) and comprising a spindle (32) and a nut (36), in which position it can press the friction member against a rotor of the vehicle brake, wherein the spindle (32) and the nut (36) engage with one another via a thread pair and an effective length of the spindle / nut arrangement (30) can be extended by a relative rotation taking place between the spindle (32) and the nut (36) in order to transmit a contact force to the brake piston (20), wherein the spindle (32) has a spindle thread (34) designed as an external thread, with at least one solid-state component (74; 78; 82;92) which is in contact with the thread pair and has lubricating properties, wherein the solid component (74; 78; 82; 92) consists of a solid lubricant or contains at least one solid lubricant, ; characterized by that two pin-shaped solid components (74) are arranged transversely to the central axis (A) and opposite one another and are prestressed in the direction of the spindle thread (34) by a bow spring (76) encompassing the spindle / nut arrangement (30). [2] Vehicle brake according to claim 1, characterized by that the pin-shaped solid-state component (74) is displaceably arranged in a bore (72; 73) of the spindle / nut arrangement (30) which is open to a spindle thread (34) of the thread pair. [3] Vehicle brake according to one of the preceding claims, characterized bythat one of the components spindle (32) and nut (36) is secured against rotation and is moved translationally along the axis (A) towards or away from the brake piston (20) by rotation of the other component nut (36) or spindle (32) depending on the direction of rotation.

Images