Coupling assembly and belt drive

Abstract

Coupling assembly (10) for a belt drive (12) of a vehicle steering assembly (14), in particular for a ball screw drive, with a belt pulley (16) and an output element (22) which is coupled in a rotationally fixed manner to the belt pulley (16), in particular a ball nut of a ball screw drive, wherein a damping assembly (30) is provided between the output element (22) and the belt pulley (16), characterized in that the damping assembly (30) is held in a rotationally fixed manner and immovably in the longitudinal direction (L) on the belt pulley (16) or on the output element (22), and a torque transmission profile (28) is provided on the output element (22) or on the belt pulley (16), into which torque transmission profile the damping assembly (30) engages, wherein the damping assembly (30) has a profile corresponding to the torque transmission profile (28), and the torque transmission profile (28) is formed by a plurality of,projections (26) projecting in the radial direction and the damping assembly (30) has recesses (34) for receiving the projections (26).

Description

[0001] The invention relates to a coupling assembly for a belt drive of a vehicle steering assembly having the features of the preamble of claim 1. The invention further relates to a belt drive for a vehicle steering assembly.

[0002] Such a coupling assembly or belt drive is known from DE 103 92 534 T5. A damping assembly in the form of a rubber insulator is provided between an output element and a pulley.

[0003] From DE 101 93 475 T1 a ball screw shaft is known in which an elastic member is arranged between a ball screw nut and a rotor.

[0004] Such coupling assemblies are used, for example, in steering assemblies in vehicles. The belt drive can transmit an assist force, provided, for example, by a steering assist drive, to the steering linkage. The pulley is coupled to the output element, which can convert the rotary motion of the pulley into a linear motion of the steering linkage. This output element is, for example, a ball screw nut mounted on a thread provided on the steering linkage. The belt drive rotates this ball screw nut against the steering linkage, causing the steering linkage to move longitudinally against the ball screw nut.

[0005] However, with such a belt drive, disturbing vibrations from the drive can be transmitted via the belt to the steering linkage and thus also to the vehicle's steering wheel.

[0006] The object of the invention is to provide a coupling assembly and a belt drive which enables a better decoupling of the steering linkage from vibrations which can be caused by a steering assistance drive.

[0007] To achieve this objective, a coupling assembly for a belt drive of a vehicle steering assembly is provided, in particular for a ball screw drive, comprising a belt pulley and an output element coupled to the belt pulley in a rotationally fixed manner, in particular a ball nut of a ball screw drive, wherein a damping assembly is provided between the output element and the belt pulley. Such a damping assembly reliably prevents or at least significantly reduces the transmission of vibrations to the output element and thus to the steering linkage. The damping assembly is arranged such that the transmission of torque from the belt pulley to the output element is not restricted, but vibrations can be reliably minimized.

[0008] The damping assembly is mounted on the pulley or output element in a rotationally fixed and longitudinally immovable manner. A torque transmission profile is provided on the output element or pulley, into which the damping assembly engages. This arrangement ensures reliable transmission of torque from the pulley to the output element. Preferably, the pulley or output element is designed such that it engages the torque transmission profile together with the damping assembly, ensuring reliable torque transmission.

[0009] A torque transmission profile is provided on the pulley or the output element, and the damping assembly has a profile corresponding to the torque transmission profile, with these elements engaging positively. Preferably, in this embodiment, the damping assembly is supported by the output element or pulley, with the output element or pulley also engaging in the torque transmission profile. The damping assembly is thus arranged such that, although it can be pressed together in sections between the pulley and the output element, it is always supported by the pulley or the output element, so that the damping assembly only has to transmit compressive forces.

[0010] The torque transmission profile is formed by several radially projecting protrusions, and the damping element has recesses to accommodate the protrusions. The number and shape of the protrusions can be adapted to the desired torque to be transmitted or to the dimensions of the damping assembly.

[0011] In order to create a rotationally fixed and longitudinally immovable connection between the pulley and the output element, the projections are clamped or fixed, for example, between the damping element and the pulley or the output element.

[0012] The damping assembly is preferably annular, and a radial flange is provided on the pulley or the output element, to which the damping assembly is attached. Depending on the design of the coupling assembly, the flange can protrude radially inward or outward to enable attachment of the damping assembly. The attachment can be achieved using conventional fastening means, such as rivets or screws, thus allowing reversible attachment of the damping assembly.

[0013] The damping assembly can be constructed in multiple parts and comprise a support, which is in particular fastened to the pulley or to the output element, and at least one damping element which is fixed to the support and rests against the output element or the pulley. The support is made, for example, from a stiffer material, thus enabling better attachment of the damping assembly to the output element or to the pulley. In addition, individual damping elements can be positioned on the support in such a way that they enable the most effective vibration damping possible, but also allow a compact design of the damping assembly. For example, the damping elements can be provided exclusively in the region of the projections. In such an embodiment, the damping elements are located radially and / or circumferentially between the pulley or the output element and the support.

[0014] The damping element is made of plastic, rubber or another damping material, for example, and can be vulcanized onto the carrier so that a material connection is created between the carrier and the damping element.

[0015] The support is preferably made of a stiffer material, such as metal or plastic.

[0016] In a preferred embodiment, the pulley is a sleeve that circumferentially encloses the output element and the damping element, so that the output element and the damping element are protected from external influences within this sleeve. This also allows for a very compact design of the coupling assembly.

[0017] According to the invention, a belt drive for a vehicle steering assembly with a coupling assembly according to the invention is further provided, wherein the belt pulley is coupled to a drive, in particular a steering assistance drive, via a belt and the output element is coupled to a steering linkage, in particular to a ball screw drive.

[0018] In this embodiment, the output element is, for example, a ball nut of a ball screw drive.

[0019] Further advantages and features can be found in the following description in conjunction with the attached drawings. These show: Fig. 1 a perspective, partially sectioned view of a coupling assembly according to the invention, Fig. 2 a schematic representation of a belt drive according to the invention with the coupling assembly from Fig. 1, Fig. 3 the output element of the coupling assembly Fig. 1, the Fig. 4a and Fig. 4b the damping assembly of the coupling assembly Fig. 1 in two perspective views, and the Fig. 5a to Fig. 5d various assembly steps of the coupling assembly from Fig. 1.

[0020] In Fig. 1 shows a coupling assembly 10 which is part of a Fig. 2 schematically illustrated belt drive 12 for a vehicle steering assembly 14.

[0021] The coupling assembly 10 has a pulley 16 which, as shown in Fig. 2, is connected to a drive 20 via a belt 18. Furthermore, the coupling assembly 10 has an output element 22 which is connected in a rotationally fixed manner to the pulley 16, and a damping assembly 30 arranged between the pulley 16 and the output element 22.

[0022] As in Fig. As can be seen in Figure 1, the pulley 16 in the embodiment shown here is a sleeve that circumferentially surrounds the output element 22. On the outside, the pulley 16 has a contact surface 23 for the belt 18.

[0023] The output element 22 is also sleeve-shaped and encloses the steering linkage 24 of the steering assembly 14 in the circumferential direction. In the embodiment shown here, the output element 22 is a ball nut of a ball screw drive, which is mounted on a steering linkage 24 of the vehicle steering assembly 14 ( Fig. 2). The output element 22 is, as explained below, non-rotatably coupled to the pulley 16.

[0024] A thread 25 is provided on the steering linkage 24. On the inside of the output element 22, a thread 27 (not shown in detail) corresponding to the thread 25 of the steering linkage 24 is provided. The output element 22 is coupled to the steering linkage 24 by suitable transmission elements, such as balls, which engage both the thread 25 of the steering linkage 24 and the thread 27 of the output element 22.

[0025] If the coupling assembly 10 is rotated by the belt drive 12, the steering linkage 24 is displaced by the coupling assembly 10 in the longitudinal direction L against the coupling assembly 10, whereby a steering movement can be supported.

[0026] The damping assembly 30 arranged between the belt pulley 16 and the output element 22 dampens vibrations of the belt drive 12 so that they do not act on the steering linkage 24 or only act to a significantly reduced extent.

[0027] The structure of the coupling module 10 is described in detail below.

[0028] As in Fig. 3, the output element 22 has a plurality of projections 26 projecting radially on its radial outer side. The projections 26 are arranged on a plane perpendicular to the longitudinal axis L and are distributed evenly in the circumferential direction on the outer circumference of the output element 22. Together, the projections 26 form a torque transmission profile 28, with which the damping assembly 30 and the pulley 16 can be coupled.

[0029] As in the Fig. 4a and Fig. As can be seen in Figure 4b, the damping assembly 30 has a carrier 32 that is essentially annular. The carrier 32 is made of a rigid material, such as metal or plastic. The inner diameter of the carrier 32 essentially corresponds to the outer diameter of the output element 22, and the outer diameter of the carrier essentially corresponds to the inner diameter of the pulley 16. The carrier 32 can therefore be inserted into the sleeve-like pulley 16 and pushed onto the output element 22.

[0030] The support 32 further comprises a plurality of substantially rectangular recesses 34, the shape of which substantially corresponds to the cross-section of the projections 26. Due to these recesses 34, the support 32 has a rectangular profile in the circumferential direction. Fastening openings 36 are arranged in the sections 35 provided between the recesses 34.

[0031] Damping elements 38 made of a soft, damping material are provided in each of the recesses 34. The damping elements 38 are essentially U-shaped, with a base 40 and two side parts 42. Extensions 44 facing each other are provided at the free ends of the side parts 42.

[0032] As in Fig. 1, the pulley has a flange 46 at one axial end which contains a plurality of mounting holes 48 which correspond to the mounting holes 36 of the carrier 32 of the damping assembly 30.

[0033] To assemble the coupling assembly 10, the damping assembly 30 is placed on the output element 22 so that the projections 26 of the output element 22 engage in the recesses 34 of the damping assembly 30 ( Fig. 5a and Fig. 5b). The damping assembly 30 is thus connected to the output element 22 in a rotationally fixed manner. In this position, the output element 22 rests exclusively on the damping elements 38 and has no contact with the carrier 32.

[0034] As in Fig. 5b, the sections 35 and the radial end faces of the projections 26 lie essentially in a plane which is perpendicular to the longitudinal direction L.

[0035] Subsequently, the pulley 16 is pushed onto the output element 22 in the direction opposite to the mounting direction of the damping assembly 30 until the flange 46 rests against the damping assembly 30 or the sections 35 of the carrier 32. Direct contact with the projections 26 of the output element 22 is prevented by the extensions 44 of the damping elements 38.

[0036] After appropriate alignment of the pulley 16, it is connected to the support 32 of the damping assembly 30 by means of fastening means 50 which are guided through the fastening openings 36, 48.

[0037] The fastening means 50 can, for example, be screws, each of which engages a thread in the fastening openings 36 of the carrier 32. Alternatively, rivets or other suitable fastening means 50 can also be used.

[0038] The fastening means 50 connect the pulley 16 and the damping assembly 30 or the carrier 32 in a rotationally fixed manner. The damping assembly 30 engages the torque transmission profile 28 formed by the projections 26, so that the damping assembly 30 is rotationally fixedly coupled to the output element 22. Thus, torque transmission from the pulley 16 to the output element 22 is possible.

[0039] As particularly in Fig. 1, the pulley 16 has no direct contact with the output element 22. The output element 22 rests exclusively on the damping elements 38 of the damping assembly 30. Vibrations transmitted via the belt drive 12 to the pulley 16 are damped or completely reduced by the damping elements 38 of the damping assembly 30, so that they cannot be transmitted to the output element 22 and the steering linkage 24.

[0040] As particularly in Fig.As can be seen in Figure 1, the projections 26 of the output element 22 are clamped between the damping assembly 30 or the carrier 32 and the pulley 16 or the flange 46 of the pulley 16, so that the components of the coupling assembly 10 are not only connected to one another in a rotationally fixed manner, but are also fixed to one another in the longitudinal direction L. Loosening of the components, for example due to vibrations, is thus reliably prevented. Since the damping assembly 30 is enclosed by the pulley 16 in the circumferential direction, it is also reliably protected from external influences.

[0041] In the embodiment shown here, the torque transmission profile 28 formed by the projections 26 is arranged on the output element 22. The damping assembly 30 is connected in a rotationally fixed manner to the pulley 16 and engages the torque transmission profile 28.

[0042] However, it is also possible for the torque transmission profile 28 to be provided on the pulley 16 and for the damping assembly to be held on the output element 22. For this purpose, the output element 22 can, for example, have a flange projecting radially outward.

[0043] The torque transmission profile 28 can also be designed differently, regardless of whether it is attached to the pulley 16 or the output element 22. It is only necessary to ensure that the torque transmission profile 28 enables reliable transmission of the torque from the pulley 16 to the output element 22. Furthermore, the torque transmission profile 28 must be designed such that the damping assembly 30 can be arranged between the pulley 16 or the output element 22 and the torque transmission profile 28.

[0044] In the embodiment shown here, the damping assembly 30 is formed in two parts, with a rigid support 32, for example made of sheet metal, onto which individual damping elements 38 are applied, for example vulcanized. The damping elements 38 are positioned such that they prevent direct contact between the output element 22 and the support 32. The extensions 44 also prevent the pulley 16 from contacting the projections 26.

[0045] The damping elements 38 are therefore arranged exclusively in the areas required for vibration damping. However, it is also possible for a continuous damping element 38 to be applied to the carrier 32, for example, to reduce the manufacturing effort of the damping assembly 30.

[0046] Depending on the shape of the torque transmission profile and the pulley or output element, the damping assembly 30 can also be formed as a single piece. It is only necessary to ensure that no direct contact is established between the pulley 16 and the output element 22; rather, this contact occurs via the damping assembly 30, which can dampen or minimize any vibrations that occur.

Claims

[1] Coupling assembly (10) for a belt drive (12) of a vehicle steering assembly (14), in particular for a ball screw drive, with a belt pulley (16) and an output element (22) coupled in a rotationally fixed manner to the belt pulley (16), in particular a ball nut of a ball screw drive, wherein a damping assembly (30) is provided between the output element (22) and the belt pulley (16), characterized bythat the damping assembly (30) is held on the pulley (16) or on the output element (22) in a rotationally fixed manner and immovably in the longitudinal direction (L), and a torque transmission profile (28) is provided on the output element (22) or on the pulley (16), into which the damping assembly (30) engages, wherein the damping assembly (30) has a profile corresponding to the torque transmission profile (28), and the torque transmission profile (28) is formed by a plurality of projections (26) projecting in the radial direction, and the damping assembly (30) has recesses (34) for receiving the projections (26). [2] Coupling assembly according to claim 1, characterized by that the projections (26) are clamped or fixed between the damping assembly (30) and the pulley (16) or the output element (22). [3] Coupling assembly according to one of claims 1 or 2, characterized bythat the damping assembly (30) is annular and a radial flange (46) is provided on the pulley (16) or on the output element (22), to which the damping assembly (30) is fastened. [4] Coupling assembly according to one of the preceding claims, characterized by that the damping assembly (30) has a carrier (32) which is fastened in particular to the pulley (16) or to the output element (22), and at least one damping element (38) which is fixed to the carrier (32) and bears against the output element (22) or the pulley (16). [5] Coupling assembly according to claim 4, characterized by that the at least one damping element (38) consists of plastic or rubber and is in particular vulcanized onto the carrier (32). [6] Coupling assembly according to claim 4 or 5, characterized by that the carrier (32) is made of metal. [7] Coupling assembly according to one of the preceding claims, characterized bythat the pulley (16) is a sleeve which encloses the output element (22) and the damping assembly (30) in the circumferential direction. [8] Belt drive (12) for a vehicle steering assembly (14) with a coupling assembly (10) according to one of the preceding claims, wherein the pulley (16) is coupled to a drive (20) via a belt (18) and the output element (22) is coupled to a steering linkage (24), in particular to a ball screw drive. [9] Belt drive according to claim 8, characterized by that the output element (22) is a ball nut of a ball screw drive.

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