Actuator assembly for an electromechanical vehicle brake

Abstract

An actuator assembly is proposed for an electromechanical vehicle brake, comprising a brake caliper (12) in which an intermediate space (14) for a brake rotor (16) is formed, wherein a brake pad (18) that can be applied to the brake rotor (16) is arranged in the intermediate space (14), a spindle drive (20) that has a spindle sleeve (22), a spindle nut (24) and an electric motor-driven drive shaft (26) for adjusting the spindle nut (24) via the spindle sleeve (22) in the axial direction, wherein the spindle nut (24) can be moved between an extended and a retracted position by axial adjustment and the drive shaft (26) is coupled to the spindle sleeve (22) via a gear (28), and wherein the gear (28) is arranged at least partially within the spindle nut (24) and / or the spindle sleeve (22) in the axial direction.

Description

[0001] The invention relates to an actuator assembly for an electromechanical vehicle brake.

[0002] Actuator assemblies in vehicle brakes are used to apply a brake pad to a brake rotor. For this purpose, the actuator assembly typically includes a spindle drive with a spindle nut and an electric motor-driven spindle for axially moving the spindle nut. An axial feed force for applying the brake pad to the brake rotor is transmitted from the spindle nut to the brake pad.

[0003] The electric motor, which drives the spindle drive, is arranged eccentrically to the drive axis of the spindle drive with respect to its drive axis.

[0004] In order to couple the electric motor with the spindle drive, a single-stage gearbox is provided between the electric motor and the spindle and, in addition, a planetary gearbox is provided on the spindle in order to be able to provide a corresponding axial feed force for applying the brake pad.

[0005] The installation space conditions in the area of ​​actuator assemblies for electromechanical vehicle brakes are usually very limited.

[0006] Consequently, the application area of ​​actuator assemblies always depends on their installation space requirements, whereby a relatively high installation space requirement of an actuator assembly is disadvantageous.

[0007] It is therefore the object of the invention to provide an actuator assembly for an electromechanical vehicle brake which has a particularly small installation space requirement.

[0008] The object is achieved according to the invention by an actuator assembly for an electromechanical vehicle brake, with a brake calliper in which an intermediate space for a brake rotor is formed, wherein a brake pad which can be applied to the brake rotor is arranged in the intermediate space, a spindle drive which has a spindle sleeve, a spindle nut and an electric motor-driven drive shaft for adjusting the spindle nut via the spindle sleeve in the axial direction, wherein the spindle nut can be moved between an extended and a retracted position by axial adjustment, wherein the drive shaft is coupled to the spindle sleeve via a gear, and wherein the gear is arranged at least partially within the spindle nut and / or the spindle sleeve in the axial direction.

[0009] The basic idea of ​​the invention is to reduce the installation length of the actuator assembly by utilizing the unused space within the spindle nut and / or spindle sleeve to at least partially arrange the gear unit, which is required to drive the spindle drive via an electric motor, within the spindle nut and / or spindle sleeve. The spindle sleeve sits within the spindle nut and drives it via the spindle drive, for example, the interposed balls.

[0010] Consequently, the installation space occupied by the actuator assembly is reduced, so that installation space can be saved and at the same time the available installation space within the actuator assembly itself is used more effectively.

[0011] The term "gearbox" refers only to the gears or toothed sections that form the gear box, without considering, for example, the shafts or sleeves on which the gears or toothed sections are mounted. These can optionally be located partially or entirely outside the spindle nut and / or spindle sleeve.

[0012] According to one aspect of the invention, the gear can be arranged completely within the spindle nut and / or the spindle sleeve in the axial direction.

[0013] This is a particularly effective arrangement to save the installation space occupied by the actuator assembly and at the same time to use the installation space available within the actuator assembly as effectively as possible.

[0014] Furthermore, the drive shaft can have a pinion, while the spindle sleeve has internal teeth.

[0015] The pinion of the drive shaft and the internal toothing of the spindle sleeve are part of the gearbox, so that at least some of the components already present in the actuator assembly are used to provide components or parts of the gearbox.

[0016] Furthermore, the spindle sleeve can have a cavity in which at least part of the gear is accommodated, wherein the internal toothing extends only over a part of the total axial length of the cavity.

[0017] The fact that the internal gearing extends only over a part of the total axial length of the cavity makes the production of the internal gearing easier.

[0018] Furthermore, the internal gearing can be designed as a single piece with the spindle sleeve. This simplifies the assembly of the actuator assembly, as no additional component is required that contains the internal gearing and must be securely coupled to the spindle sleeve.

[0019] The gearbox can be a single-stage gearbox.

[0020] A single-stage gearbox allows the implementation of a simple gearbox with few components and still allows for an appropriate gear ratio to be provided between the electric motor and the spindle drive.

[0021] In addition, single-stage gearboxes can be designed to be particularly robust.

[0022] The gearbox can be a planetary gearbox, with the internal teeth forming a ring gear and the pinion forming a sun gear, and planetary gears being provided in between which mesh with the teeth of the pinion and the internal teeth of the spindle sleeve.

[0023] Consequently, as already described above, the planetary gear consists largely of existing components of the actuator assembly, so that only the pinion needs to be provided on the drive shaft and the internal toothing needs to be introduced into the spindle sleeve designed as a ring gear.

[0024] Therefore, only the planetary gears are additionally necessary to form the planetary gear.

[0025] Alternatively, the transmission can also be a multi-stage transmission.

[0026] This allows a larger gear ratio to be achieved between the electric motor or drive shaft and the spindle nut or spindle sleeve.

[0027] The gearbox can also be a Wolfrom gearbox, where the internal teeth form a ring gear and the pinion forms a sun gear. In addition, a non-rotating ring gear sleeve with ring gear teeth is provided, arranged coaxially to the drive shaft, as well as planet gears of a first stage and thus rotationally coupled planet gears of a second stage, which in pairs have the same central axis but a different pitch circle than the planet gears of the first stage, with the planet gears of the first stage engaging with the teeth of the pinion and a ring gear toothing of the ring gear sleeve, and the planet gears of the second stage engaging with the internal teeth of the spindle sleeve. A Wolfrom gearbox is a high-ratio planetary gearbox which is extremely compact and is characterized by a minimal difference in the pitch circles of the two ring gears, through which the high gear ratio is achieved.

[0028] The ring gear sleeve can be coupled to the brake caliper in a rotationally fixed manner. A planetary carrier can also be provided to hold the planetary gears of the first and second stages.

[0029] The planet carrier can consist of webs and cheeks, whereby holes can be provided in the cheeks into which planetary axles are pressed in order to save costs.

[0030] The planetary gears are mounted on the planetary axes so that they can rotate, e.g. with plain bearings, in order to save space and costs.

[0031] The Wolfrom gearbox is particularly suitable for this purpose because, on the one hand, it requires very little installation space, allowing it to be easily installed within the spindle nut and / or spindle sleeve. On the other hand, it allows for high transmission ratios.

[0032] The ring gear sleeve can extend into the interior of the spindle nut and / or the spindle sleeve. This also allows the actuator assembly to require very little installation space.

[0033] Furthermore, the drive shaft can be mounted in the ring gear sleeve via a rolling bearing.

[0034] Consequently, the ring gear sleeve performs several functions, as it has the ring gear teeth for the first stage of the planetary gears and at the same time accommodates and supports the drive shaft.

[0035] Furthermore, a planet carrier can be provided, which is mounted on the one hand in the spindle sleeve and on the other hand in the ring gear sleeve.

[0036] Furthermore, the drive shaft can be coupled to a motor shaft of an electric motor without a gear or can be coupled to a motor shaft of an electric motor via a gear unit arranged completely outside the spindle nut and / or the spindle sleeve, in particular a single-stage gear unit.

[0037] Accordingly, no additional gear is required, reducing manufacturing costs and the complexity of the actuator assembly.

[0038] Alternatively, only a single-stage gearbox is required, which can be provided particularly easily and cost-effectively.

[0039] The invention is described below with reference to an embodiment illustrated in the accompanying drawings, in which: - Fig. 1 a sectional view of an actuator assembly according to the invention, - Fig. 2 a half-section of a part of a spindle drive with a Wolfrom gear of the actuator assembly according to the invention in a perspective view; - Fig. 3 the part of the spindle drive with the Wolfrom gear from Fig. 2 in an exploded view; - Fig. 4 a schematic representation of a back side of the module cap according to the invention, which in Fig. 3 can be seen; and - Fig. 5 the representation from Fig. 3 without Wolfrom gearbox.

[0040] Fig. 1 shows an actuator assembly 10 for an electromechanical vehicle brake.

[0041] The actuator assembly 10 comprises a brake caliper 12 in which a space 14 for a brake rotor 16 is formed.

[0042] In the intermediate space 14, at least one brake pad 18 is arranged on each side of the brake rotor 16, which can be applied to the brake rotor 16.

[0043] Furthermore, the actuator assembly 10 comprises a spindle drive 20, which in the exemplary embodiment is a ball screw drive, with a rotatably mounted, electric motor-driven spindle sleeve 22, on which a spindle nut 24 for applying the brake pad 18 to the brake rotor 16 is mounted on the outer casing.

[0044] Furthermore, a drive shaft 26 is provided, which serves to drive the spindle sleeve 22, wherein the spindle nut 24 can in turn be adjusted axially via the spindle sleeve 22.

[0045] The spindle nut 24 is adjustable by axial displacement between an extended and a retracted position and is linearly guided in the brake caliper 12. The spindle sleeve 22 and spindle nut are coupled to each other via a recirculating ball system, so that when the spindle sleeve 22 rotates, the non-rotatable spindle nut 24 is axially adjusted.

[0046] The spindle nut 24 of the spindle drive 20 represents in particular a brake piston.

[0047] The drive shaft 26 is coupled to the spindle sleeve 22 via a gear 28.

[0048] The spindle sleeve 22 has a cavity 30 within which the gear 28 is received, so that it is arranged at least partially within the spindle nut 24 and the spindle sleeve 22 in the axial direction.

[0049] According to the Fig. 1 to 4, the gear 28 can be arranged completely within the spindle sleeve 22.

[0050] Furthermore, it can also be arranged completely within the spindle nut 24.

[0051] Alternatively, it is also conceivable that the gear 28 is only partially arranged within the spindle nut 224 and / or the spindle sleeve 22 in the axial direction.

[0052] The gear 28 comprises a pinion 32 with a toothing 33. The pinion 32 is provided on the drive shaft 26.

[0053] In addition, the gear 28 comprises an internal toothing 34 which is formed on the inside of the spindle sleeve 22.

[0054] The internal toothing 34 extends only over a part of the total axial length of the cavity 30 of the spindle sleeve 22.

[0055] Consequently, only the gears or toothed sections are considered to be gears, without taking into account the shafts or sleeves on which the gears or toothed sections are provided.

[0056] The internal toothing 34 is formed integrally with the spindle sleeve 22.

[0057] According to a first option, the gear 28 is a multi-stage planetary gear in the form of a Wolfrom gear 36.

[0058] In this Wolfrom gear 36, the pinion 32 is arranged coaxially to the spindle nut 24 and spindle sleeve 22, so that a sun gear 38 is formed by the pinion 32.

[0059] The internal toothing 34 on the spindle sleeve 22 is in turn arranged coaxially to the pinion 32 and forms a ring gear 40.

[0060] In addition, a ring gear toothing 42 is part of the gear 28 designed as a Wolfrom gear 36, which is provided on a ring gear sleeve 44.

[0061] The ring gear sleeve 44 extends into the interior of the spindle sleeve 22. Consequently, the ring gear sleeve 44 has a region that axially overlaps with the cavity 30.

[0062] The drive shaft 26 is mounted via rolling bearings 45 within the ring gear sleeve 44.

[0063] The ring gear sleeve 44 is rotationally fixedly coupled to the brake caliper 12.

[0064] Furthermore, the transmission 28 comprises a planet carrier 46 of a first stage 48 and planet gears 50 of a second stage 52 which are rotationally coupled thereto.

[0065] The planet gears 46, 50 each have the same central axis M1 to M4 in pairs.

[0066] However, the pitch circle of the planet gears 46 of the first stage 48, on which they roll on the outside, differs minimally from the pitch circle of the planet gears 50 of the second stage 52.

[0067] The pitch circle of the planet gears 46 is smaller than that of the planet gears 50.

[0068] A planet carrier 54 with webs 56 and cheeks 58 is provided for supporting the planet gears 46, 50.

[0069] In the cheeks 58 there are holes 60 into which planetary axes 62 are pressed.

[0070] On each of the planetary axes 62, a planetary gear 46 is rotatably mounted in pairs together with a planetary gear 50.

[0071] The planet carrier 54 is in turn mounted on the one hand in the spindle sleeve 22 and on the other hand in the ring gear sleeve 44.

[0072] The planetary gears 46 of the first stage 48 mesh with the toothing 33 of the pinion 32 and with the internal toothing 34. The planetary gears 50 of the second stage 52 mesh with the ring gear toothing 42 of the ring gear sleeve 44.

[0073] If the spindle nut is now to be adjusted in the axial direction, the drive shaft 26 is set in rotation.

[0074] As a result, the pinion 32 rotates, driving the planetary gears 46 of the first stage 48, which come into engagement with the ring gear teeth 42 of the torsion-resistant ring gear sleeve 44.

[0075] Since each of the planetary gears 46 of the first stage 48 is rotationally fixedly coupled to a respective planetary gear 50 of the second stage 52, the planetary gears 50 also perform a rotational movement.

[0076] Here they engage with the internal toothing 34, so that a force flow exists between the drive shaft 26 and the spindle sleeve 22.

[0077] As a result, the spindle sleeve 22 performs a rotary movement which is accompanied by a linear adjustment of the spindle nut 24.

[0078] According to a second option, the transmission 28 can also be designed as a single-stage transmission (not shown in the figures).

[0079] The gear is a planetary gear in which the internal toothing 34 on the spindle sleeve 22 also forms a ring gear and the pinion 32 forms the sun gear of the planetary gear.

[0080] Between the ring gear formed by the internal toothing 34 and the pinion 32 acting as a sun gear, planetary gears are provided which engage with the toothing of the pinion and the internal toothing of the spindle sleeve.

[0081] In both of the options explained, the actuator assembly 10 also includes an electric motor 64 with a motor shaft.

[0082] The electric motor 64 serves to move the spindle nut 24 between the retracted position and the extended position.

[0083] The motor shaft is coupled to the drive shaft 26 via a single-stage gear unit 68, wherein the single-stage gear unit 68 is arranged completely outside the spindle sleeve 22.

[0084] Alternatively, it is conceivable that the drive shaft 26 is coupled to the motor shaft of the electric motor 64 without a gear, so that the motor shaft is arranged coaxially to the drive shaft 26.

Claims

[1] Actuator assembly for an electromechanical vehicle brake, with a brake calliper (12) in which an intermediate space (14) for a brake rotor (16) is formed, wherein a brake pad (18) is arranged in the intermediate space (14) and can be applied to the brake rotor (16), a spindle drive (20) having a spindle sleeve (22), a spindle nut (24) and an electric motor-driven drive shaft (26) for adjusting the spindle nut (24) via the spindle sleeve (22) in the axial direction, wherein the spindle nut (24) can be moved between an extended and a retracted position by axial adjustment, wherein the drive shaft (26) is coupled to the spindle sleeve (22) via a gear (28), and wherein the gear (28) is arranged at least partially within the spindle nut (24) and / or the spindle sleeve (22) in the axial direction. [2] Actuator assembly according to claim 1, characterized bythat the gear (28) is arranged completely within the spindle nut (24) and / or the spindle sleeve (22) in the axial direction. [3] Actuator assembly according to claim 1 or 2, characterized by that the drive shaft (26) has a pinion (32) and the spindle sleeve (22) has an internal toothing (34). [4] Actuator assembly according to claim 3, characterized by that the spindle sleeve (22) has a cavity (30) in which at least part of the gear (28) is accommodated and that the internal toothing (34) extends only over part of the total axial length of the cavity (30). [5] Actuator assembly according to claim 3 or 4, characterized by that the internal toothing (34) is made in one piece with the spindle sleeve (22). [6] Actuator assembly according to one of the preceding claims, characterized by that the gearbox (28) is a single-stage gearbox (28). [7] Actuator assembly according to one of claims 3 to 6, characterized bythat the gear (28) is a planetary gear, wherein the internal toothing (34) forms a ring gear (40) and the pinion (32) forms a sun gear (38) and planetary gears are provided between them, which engage in the toothing (33) of the pinion (32) and the internal toothing of the spindle sleeve (22). [8] Actuator assembly according to one of claims 1 to 5, characterized by that the gearbox (28) is a multi-stage gearbox. [9] Actuator assembly according to one of claims 3 to 5 or according to claim 8, characterized bythat the gear (28) is a Wolfrom gear (36), wherein the internal toothing (34) forms a ring gear (40) and the pinion (32) forms a sun gear (38), and furthermore a non-rotating ring gear sleeve (44) arranged coaxially to the drive shaft (26) with a ring gear toothing (42) is provided, as well as planet gears (46) of a first stage (48) and thus rotationally coupled planet gears (50) of a second stage (52), which in pairs have the same central axis (M1-M4) but a different pitch circle than the planet gears (46) of the first stage (48), wherein the planet gears (46) of the first stage (48) engage in the toothing (33) of the pinion (32) and the ring gear toothing (42) of the ring gear sleeve (44), and the planet gears (50) of the second stage (52) engage in the internal toothing (34) of the Engage spindle sleeve (22). [10] Actuator assembly according to claim 9, characterized by that the ring gear sleeve (44) extends into the interior of the spindle sleeve (22). [11] Actuator assembly according to claim 9 or 10, characterized by that the drive shaft (26) is mounted in the ring gear sleeve (44) via a rolling bearing (45). [12] Actuator assembly according to one of claims 9 to 11, characterized by that a planet carrier (54) is provided which is mounted on the one hand in the spindle sleeve (22) and on the other hand in the ring gear sleeve (44). [13] Actuator assembly according to one of the preceding claims, characterized by that the drive shaft (26) is coupled to a motor shaft of an electric motor (64) without a gear, or that the drive shaft (26) is coupled to a motor shaft of an electric motor (64) via a gear unit, in particular a single-stage gear unit, arranged completely outside the spindle sleeve (22).

Images