Pulley and steering mechanism

Abstract

A belt pulley (28) for a gear mechanism has a hollow-cylindrical body (36) and a disc-shaped fixing flange (42) which is molded on an axial end of the body, projects radially inwards and has a central cutout (44). The fixing flange has at least one first contact surface (60) on its inner side, and the body has at least one second contact surface (64) on the inner side. The first contact surface and the second contact surface are offset from one another in a circumferential direction with respect to a central axis of the body. The at least one second contact surface, or in the case of several second contact surfaces all of the second contact surfaces, is perpendicular to a plane in which the at least one first contact surface, or in the case of several first contact surfaces all of the first contact surfaces, lies, the at least one first contact surface and the at least one second contact surface being raised with respect to the adjacent surfaces. The invention also relates to a steering mechanism for a vehicle, wherein the steering mechanism comprises a belt pulley (28).

Description

Technical Field

[0001] The present invention relates to a pulley for a gear mechanism and a steering mechanism for a motor vehicle. Background Technology

[0002] To keep the rotating mass of the gear mechanism low, it is known to make the rotating mass from lightweight materials; for example, using pulleys made of plastic. The pulley is then attached to the mounting flange of a threaded nut in the gear mechanism by a fixing bolt. The fixing force of the bolt generates material stress in the pulley, and these forces can potentially damage the pulley.

[0003] To avoid such damage and absorb the fixing force of the bolts, the plastic body is typically reinforced in a targeted manner with metal inserts in specific locations. This requires either placing the metal insert in the mold before the pulley is injection molded, or placing the metal insert on the body and molding it into it after injection molding, necessitating at least a two-stage production process. Summary of the Invention

[0004] Therefore, the object of the present invention is to produce a robust pulley that is easy to manufacture.

[0005] To achieve this objective, a pulley for a gear mechanism is provided, the pulley having a hollow cylindrical body and a disc-shaped fixed flange molded on the axial end of the body and projecting radially inward. The fixed flange has a central notch and at least one first contact surface on its inner side. The body has at least one second contact surface on its inner side. The first and second contact surfaces are offset from each other in a circumferential direction relative to the central axis of the body, and the at least one second contact surface, or all second contact surfaces in the case of several second contact surfaces, is perpendicular to the plane containing the at least one first contact surface, or all first contact surfaces in the case of several first contact surfaces, and the at least one first contact surface and the at least one second contact surface protrude relative to adjacent surfaces.

[0006] The basic concept of this invention is to construct the geometry of the pulley so that reinforcement with metal inserts within the pulley is unnecessary. The circumferentially offset contact surface thus allows forces generated by the fixed pulley to be introduced into different areas of the pulley. Therefore, only the molding tooling for the pulley needs to be designed according to its geometry.

[0007] In particular, the pulleys have no material inserts, thus simplifying the production process.

[0008] The contact surface is the surface on the pulley that is supported by part of the gear mechanism (such as a threaded nut).

[0009] Pulleys can be made of rigid plastic materials such as phenolic resin. These plastics are also known as thermosetting plastics.

[0010] In one aspect of the invention, viewed along the axial direction, all the first contact surfaces and all the second contact surfaces are located in different non-overlapping circumferential segments. Therefore, in each circumferential segment, the contact surfaces are arranged in a precise direction, and the pulley has a degree of elasticity between the contact surfaces and perpendicular to the contact direction. In this way, the resulting stress is better distributed in the pulley.

[0011] These circumferential sections can be evenly distributed along the circumferential direction.

[0012] The at least one second contact surface, or in the case of several second contact surfaces, may be perpendicular to the plane containing the at least one contact surface, or in the case of several first contact surfaces. In this way, a pulley that can be optimally positioned and applied to a cylindrical threaded nut in a simple manner is provided.

[0013] In one embodiment of the invention, the at least one second contact surface is a cylindrical surface portion and extends parallel to the cylindrical inner shell surface of the body. This allows the threaded nut to make partial contact on the hollow cylindrical body.

[0014] The at least one first contact surface and / or at least one second contact surface may protrude relative to the adjacent surface.

[0015] In other words, the first contact surface and / or the second contact surface are formed on the corresponding protrusion, which allows for a simple structural arrangement of one or more contact surfaces. Moreover, these raised surfaces achieve reliable contact, and the forces introduced into the contact surfaces can propagate to adjacent wall portions, thereby ensuring stress distribution.

[0016] It can be provided that the at least one second contact surface exists on a stepped molded extension on the cylindrical inner shell surface of the body. In this way, a certain degree of elasticity is provided between the force-introducing extensions of the pulley, and the resulting vibration can be compensated.

[0017] To ensure high stability of the pulley, a plurality of first contact surfaces and a plurality of second contact surfaces may exist. Here, in their respective cases, the plurality of first contact surfaces are spaced apart from each other in the circumferential direction, and the plurality of second contact surfaces are also spaced apart from each other. This also causes stress distribution.

[0018] In an embodiment of the invention, a plurality of molded extensions are provided, which are spaced apart from each other along the circumferential direction and have at least one second contact surface. This allows for a symmetrical distribution of the contact surfaces and thus allows for high stability of the pulley.

[0019] It is also envisioned that the molded extension has several second contact surfaces (e.g., two second contact surfaces).

[0020] At least one extension may be located at the transition between the body and the fixed flange. A circumferential groove may be provided at the direct transition between the radially inner side of at least one extension and the fixed flange. The circumferential groove provides a degree of elasticity to the extension and reduces stress at the transition.

[0021] In order to provide a pulley with uniform wall thickness, an axial cut extending into the extension may be provided on the end face of the fixed flange facing away from the body, in the region of at least one extension.

[0022] In the case of several extensions, an axial cut extending into the extension can be provided on the end face of the fixed flange, in the region of each extension. This cut ensures less material accumulation and a degree of flexibility.

[0023] At least one fixing opening is provided on the fixing flange, and a protruding annular ring surrounding the fixing opening may be provided on the end face of the fixing flange facing away from the body. Here, the annular ring terminates at a contact surface for fixing the device, wherein the circumferential surface of the annular ring forms the outer surface of a frustocone. In this way, the fixing material of the annular ring, and therefore the fixing flange, is partially compressed, i.e., the flange itself bears less load from the local stress of the bolt. The force of the bolt head can compress the conical ring and is uniformly transmitted to the flange.

[0024] What can be provided is that each fixed opening terminates at a first contact surface. In particular, a compressive force is generated between the corresponding first contact surface and the corresponding annular convex ring, allowing the pulley to withstand high fixing forces. Furthermore, the wall thickness is particularly large in this region, resulting in high resistance to compressive loads.

[0025] In one embodiment of the invention, the body has teeth on its outer periphery. Therefore, the pulley is a toothed pulley, allowing for efficient force transmission.

[0026] The object of the invention is also achieved by a steering mechanism for a vehicle. The steering mechanism has a threaded nut and a pulley of the type described above, the pulley being placed on and attached to the threaded nut. The threaded nut rests against a first contact surface and a second contact surface, the first and second contact surfaces forming the only contact point between the components. The advantages and features described with respect to the pulley also apply to the steering mechanism, and vice versa.

[0027] In the case of several first contact surfaces and / or second contact surfaces, the threaded nut can preferably be supported on all first contact surfaces and all second contact surfaces. Attached Figure Description

[0028] Further advantages and features will emerge from the following description and the accompanying drawings referenced below. The drawings are as follows:

[0029] Figure 1 A schematic top view of a vehicle having a steering mechanism according to the invention is shown.

[0030] Figure 2 It shows Figure 1 An exploded perspective view of the steering mechanism according to the present invention.

[0031] Figure 3 It shows passing through the assembled [structure] in the area of ​​the fixed opening. Figure 1 Axial section view of the steering mechanism.

[0032] Figure 4 Shown from below Figure 1 and Figure 2 The steering mechanism according to the first embodiment of the pulley of the present invention,

[0033] Figure 5 It shows along Figure 4 The perspective section view of the cutting line VV.

[0034] Figure 6 by Figure 5 The perspective cross-sectional view shows a second embodiment of the pulley according to the invention, and

[0035] Figure 7 It shows the passage through the region of the axial extension. Figure 6 An axial cross-sectional view of the pulley. Detailed Implementation

[0036] Figure 1 A schematic top view of a portion of vehicle 10 is shown. Vehicle 10 has a steering wheel 12, a steering mechanism 14, and wheels 16.

[0037] The steering mechanism 14 includes a toothed belt mechanism 18, which is driven on the drive side by an actuation motor 20. The actuation motor 20 receives an electronic steering signal and converts it into rotation. On the output side, the toothed belt mechanism 18 is coupled to a steering mechanism 22. The steering mechanism 22 converts the rotational motion of the toothed belt mechanism 18 into linear motion of an intermediate element 24 coupled to the wheel 16, thereby steering the vehicle 10.

[0038] exist Figure 2 In one embodiment, the steering mechanism 22 is a recirculating ball steering mechanism.

[0039] The steering mechanism 22 has a threaded nut 26 and a pulley 28. The threaded nut 26 has a cylindrical base body 30, which is provided with an outer peripheral mounting flange 32. A plurality of mounting openings 34 are provided in the mounting flange 32.

[0040] The pulley 28 is integrally made of plastic (e.g., phenolic resin) and has a hollow cylindrical body 36 with teeth 38 on its outer surface.

[0041] A radially inwardly projecting disc-shaped retaining flange 42 is provided on the end face of the cylindrical body 36 (i.e., at the axial end relative to the central axis 40 of the body), which is integrally incorporated into the body 36. The retaining flange 42 has a central notch 44. The inner diameter of the retaining flange 42 is slightly larger than the outer diameter of the threaded nut 26 axially near the mounting flange 32.

[0042] The fixed flange 42 protrudes slightly outward above the tooth 38 and forms a circumferentially closed collar 46, which terminates flush with the body 36 in the axial direction.

[0043] In the region of the fixed flange 42 located inside the cylindrical body 36, a plurality of fixed openings 48 are provided, the orientation and number of which correspond to the mounting openings 34 in the mounting flange 32 of the threaded nut 26.

[0044] On the outer side of the fixing flange 42 (i.e., on the end face of the fixing flange 42 facing away from the body 36), a molded annular protrusion 50 is provided at each fixing opening 48, which surrounds the corresponding fixing opening 48 and protrudes from the outer side of the fixing flange 42.

[0045] To secure the pulley 28 to the threaded nut 26, several fastening devices 52 are used, which are formed here by threaded bolts 54 and threaded sleeves 56. These fastening devices form a rotationally fixed connection between the pulley 28 and the threaded nut 26.

[0046] Figure 3 A cross-sectional view in the axial direction is shown through the area of ​​the fixed opening 48 through the assembled steering mechanism 22.

[0047] An annular convex ring 50 forms a contact surface 58 for a threaded bolt 54, on which the underside of the head of the threaded bolt 54 rests. The cross-section of the annular convex ring 50 is in the form of a hollow truncated cone, wherein the contact surface 58 is formed by the end face of the truncated cone having a smaller external dimension.

[0048] In the axial direction, each fixed opening 48 terminates at a first contact surface 60 on the inner side of the pulley 28, and in the installed state of the steering mechanism 22, the side of the mounting surface 32 facing the fixed flange 42 is axially supported on the first contact surface.

[0049] like Figure 4 As shown in the lower view of the pulley 28, the fixed flange 42 has a plurality of first contact surfaces 60 on its inner side. The first contact surfaces 60 are evenly spaced and distributed circumferentially around the central axis 40, and protrude relative to adjacent surfaces on the inner side of the fixed flange 42. Figure 5 Accordingly, the mounting flange 32 of the threaded nut 26 is supported only on the first contact surface 60 at the fixed flange 42, and not on the surface between the first contact surfaces 60 inside the fixed flange 42.

[0050] A stepped axial extension 62 is molded on the inner housing surface 61 of the body 36, adjacent to the first contact surface 60 in the circumferential direction, and radially offset relative to the first contact surface 60. The axial extension 62 is here arranged at the transition from the fixing flange 42 to the body 36.

[0051] Extension 62 in Figure 5 (showing along) Figure 4 The section line VV passes through the cross section of the pulley 28, as shown in detail in the perspective cross-sectional view. The corresponding circumferential groove 63 (i.e., a groove extending in the circumferential direction relative to the central axis 40 of the pulley 28) is formed at the direct transition from the fixed flange 42 to the axial extension 62.

[0052] On the side of the extension 62 facing the central axis 40, a second contact surface 64 is provided, which is arranged parallel to the cylindrical inner shell surface 61 of the body 36. Therefore, the second contact surface 64 is formed by the cylindrical surface portion of the body 36.

[0053] In other words, the second contact surface 64 is perpendicular to the radial plane on which the first contact surface 60 is arranged. Accordingly, the first contact surface 60 and the second contact surface 64 are perpendicular to each other.

[0054] The second contact surface 64 is offset relative to the first contact surface 60 in both the circumferential and axial directions.

[0055] More precisely, the first contact surface 60 and the second contact surface 64 are arranged in corresponding non-overlapping circumferential sections 66. Figure 4 In their respective cases, the first contact surfaces 60 are spaced apart from each other in the circumferential direction, and the second contact surfaces 64 are spaced apart from each other.

[0056] The second contact surface 64 of the pulley 28 is supported on a portion of the gear mechanism. For example, the second contact surface 64 of the pulley 28 is supported on... Figure 2 On the outer peripheral edge of the mounting flange 32 of the threaded nut 26 shown.

[0057] The threaded nut 26 is thus attached to the pulley 28 via a first contact surface 60 and a second contact surface 64. Because the first contact surface 60 and the second contact surface 64 are perpendicular to each other, a pulley 28 with high rigidity is provided. Therefore, additional metal inserts in the pulley 28 can be omitted. Consequently, the pulley can be easily manufactured by injection molding and corresponding molding tools.

[0058] The pulley 28 is attached to the threaded nut 26 via a retaining device 52. Both the first contact surface 60 and the annular convex ring 50 protrude relative to their adjacent surfaces, such that the retaining force applied by the retaining device 52 causes compression of the pulley 28 in the region of the first contact surface 60. The pulley 28, made of rigid plastic material, absorbs compressive forces better than tensile forces, thus enabling high retaining forces.

[0059] Now for reference Figure 6 and Figure 7 The pulley 28 according to the second embodiment is described; this second embodiment generally corresponds to the first embodiment, so only the differences are described in detail below. Identical parts and parts with equivalent functions are given the same reference numerals. Figure 6 It shows crossing Figure 5 A cross-sectional view of pulley 28.

[0060] and Figure 4 and Figure 5 Compared to the embodiment of pulley 28, the collar 46 arranged on the body 36 and protruding radially outward is not arranged flush with the fixed flange 42, but is offset in the axial direction.

[0061] Furthermore, each axial extension 62 is provided with two second contact surfaces 64, and these two second contact surfaces are spaced apart from each other by a connecting surface 68 in the circumferential direction. The second contact surface 64 of each extension 62 protrudes relative to the connecting surface 68. Figure 7 ).

[0062] Figure 7 The pulley 28 is shown in an axial cross-sectional view along the central axis 40 and through the axial extension 62. The pulley 28 is shown in the region of the axial extension 62.

[0063] Compared to the first embodiment, each extension 62 has an axial cutout 70. The cutout 70 is designed such that the wall thickness of the pulley 28 in the region of the extension 62 corresponds approximately to the wall thickness of the pulley 28 in the region of the fixed flange 42 and in the region of the body 36.

[0064] exist Figure 7 In one embodiment, the axial extension 62 is thus formed in a stepped shape in the axial section passing through the extension 62.

[0065] In other words, the axial extension 62 has a portion parallel to the radial plane and a portion perpendicular to the radial plane (i.e., in the axial direction). The circumferential groove 63 is arranged here at the transition from the fixing flange 42 to the axial portion of the extension 62.

[0066] Obviously, the various features of the two embodiments can be arbitrarily combined with each other. In particular, the features listed as distinguishing them from the second embodiment are independent and can also exist in various forms in the first embodiment.

[0067] For example, the first embodiment may also have a corresponding cut 70.

Claims

1. A pulley for a gear mechanism, the pulley having a hollow cylindrical body (36) and a disc-shaped fixing flange (42) moulded on an axial end of the body (36), projecting radially inwards and having a central cut-out (44), wherein, The fixed flange (42) has at least one first contact surface (60) on its inner side, and the body (36) has at least one second contact surface (64) on its inner side, wherein the first contact surface (60) and the second contact surface (64) are offset from each other in a circumferential direction relative to the central axis (40) of the body (36), the at least one second contact surface (64), or in the case of several second contact surfaces (64), all second contact surfaces (64) are perpendicular to the plane in which the at least one first contact surface (60), or in the case of several first contact surfaces (60), are located, and the at least one first contact surface (60) and the at least one second contact surface (64) protrude relative to adjacent surfaces.

2. The pulley of claim 1, wherein, Viewed along the axial direction, all first contact surfaces (60) and all second contact surfaces (64) are located in different circumferential segments (66) that do not overlap.

3. The pulley of claim 1 or 2, wherein, The at least one second contact surface (64) is a cylindrical surface portion and extends parallel to the cylindrical inner shell surface (61) of the body (36).

4. The pulley of claim 1 or 2, wherein, The at least one second contact surface (64) exists on a stepped molded extension (62) of the cylindrical inner shell surface (61) of the body (36).

5. The pulley of claim 1 or 2, wherein, There are a plurality of first contact surfaces (60) and a plurality of second contact surfaces (64), wherein, in their respective cases, the plurality of first contact surfaces (60) are spaced apart from each other in the circumferential direction, and the plurality of second contact surfaces (64) are spaced apart from each other.

6. The pulley of claim 4, wherein, The plurality of molded extensions (62) are provided, the plurality of molded extensions being spaced apart from each other along the circumferential direction and having at least one second contact surface (64).

7. The pulley of claim 4 or 6, wherein, The at least one molded extension (62) is located at the transition between the body (36) and the fixed flange (42), and a circumferential groove (63) is provided at the direct transition between the radially inner side of the at least one molded extension (62) and the fixed flange (42).

8. The pulley of claim 4 or 6, wherein, At least one axial cut (70) extending into the molded extension (62) is provided on the end face of the fixed flange (42) facing away from the body (36), in the region of the at least one molded extension (62) or in the region of each molded extension (62) in the case of several molded extensions (62).

9. The pulley of claim 1 or 2, wherein, At least one fixed opening (48) is provided on the fixed flange (42), and a protruding annular ring (50) is provided on the end face of the fixed flange (42) facing away from the body (36), the annular ring surrounding the fixed opening (48) and terminating at a contact surface (58) for fixing the device (52), wherein the circumferential surface of the annular ring (50) forms the outer surface of a truncated cone.

10. The pulley of claim 9, wherein, Each fixed opening (48) terminates at the first contact surface (60).

11. The pulley of claim 1 or 2, wherein, The body (36) has teeth (38) on its outer periphery.

12. A steering mechanism for a vehicle, the steering mechanism having a threaded nut (26) and a pulley (28) as claimed in any one of claims 1 to 11, the pulley being placed on and attached to the threaded nut (26), wherein, The threaded nut (26) is located on the first contact surface (60) and the second contact surface (64).

13. The steering mechanism for a vehicle as claimed in claim 12, wherein, With a plurality of first contact surfaces (60) and a plurality of second contact surfaces (64), the threaded nut (26) is located on all the first contact surfaces (60) and all the second contact surfaces (64).

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