Transmission mechanism, electric power steering system and vehicle

Abstract

The utility model belongs to the technical field of vehicle steering, and discloses a transmission mechanism, an electric power steering system and a vehicle. The transmission mechanism comprises a screw, a nut, a guide part and a lead screw, the screw is used for being connected with an external power source, the nut is in threaded connection with the screw, a first mounting part is arranged on the outer wall of the nut, a second mounting part is arranged at the first end of the guide part, and the first mounting part and the second mounting part are detachably connected through a fastener. The second end of the guide piece is detachably connected with the lead screw. The first mounting part of the nut of the transmission mechanism is detachably connected with the second mounting part arranged at the first end of the guide piece through the fastener, and the second end of the guide piece is also detachably connected with the lead screw, so that the stress concentration of the guide piece can be reduced, the service life of the guide piece is prolonged, the guide piece, the nut and the lead screw can be conveniently disassembled, and the production efficiency is improved. After the guide piece breaks down, the situation that the nut, the guide piece and the lead screw are scrapped at the same time can be avoided, and cost is effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of vehicle steering technology, and in particular to transmission mechanisms, electric power steering systems and vehicles. Background Technology

[0002] Electric power steering (EPS) is a power steering system that uses an electric motor to provide auxiliary torque. This system has many advantages, such as enhanced steering follow-through, improved steering return characteristics, improved handling stability, and the provision of variable steering assistance. It has a simple structure, and more and more vehicles are beginning to be equipped with electric power steering systems to ensure vehicle driving safety.

[0003] The working principle of an electric power steering system is that a motor is connected to a screw drive, and a nut is threaded onto the screw. The nut is connected to a lead screw via a guide component. The two ends of the lead screw are connected to two steering tie rods respectively. The rotation of the motor drives the screw to rotate, thereby transmitting axial force through the nut and guide component to the lead screw, causing displacement of the steering tie rods and achieving steering. In existing technologies, the guide component, nut, and lead screw are usually interference-fitted. Due to the design requirements of the nut, the interference contact area between it and the guide component is small, and the contact area transition is uneven. This causes stress concentration in the guide component, resulting in a weak central structure. The small interference groove between the guide component and the lead screw leads to low rigidity of the guide component, resulting in a shorter lifespan. This, in turn, affects the lifespan of the electric power steering system. Furthermore, the guide component is difficult to disassemble, leading to high replacement costs.

[0004] Therefore, a transmission mechanism, an electric power steering system, and a vehicle are needed to solve the above problems. Utility Model Content

[0005] The purpose of this utility model is to provide a transmission mechanism, an electric power steering system, and a vehicle, in which the guide component, nut, and lead screw are all detachably connected, thereby reducing stress concentration in the guide component, increasing the difficulty of disassembling and assembling the transmission system, and reducing costs.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A transmission mechanism includes a screw, a nut, a guide member, and a lead screw. The screw is used to connect to an external power source. The nut and the screw are threaded together. The outer wall of the nut is provided with a first mounting part. The first end of the guide member is provided with a second mounting part. The first mounting part and the second mounting part are detachably connected by fasteners. The second end of the guide member is detachably connected to the lead screw.

[0008] As an optional technical solution, the first mounting part is provided with a first through hole, the second mounting part is provided with a second through hole, and the fastener includes a fastening bolt and a fastening nut. The fastening bolt passes through the first through hole and the second through hole in sequence and is threadedly connected to the fastening nut to detachably connect the first mounting part and the second mounting part.

[0009] As an optional technical solution, two first mounting parts are provided, and the two first mounting parts are spaced apart on the outer wall of the nut; two second mounting parts are provided, and the two second mounting parts are spaced apart on the first end of the guide member, with the two first mounting parts and the two second mounting parts corresponding one to one.

[0010] As an optional technical solution, the first mounting part includes a plurality of first mounting seats, which are spaced apart along the axial direction of the nut. The second mounting part includes a plurality of second mounting seats, which are also spaced apart along the axial direction of the nut, and the plurality of first mounting seats and the plurality of second mounting seats are staggered.

[0011] As an optional technical solution, the second end of the guide is provided with a third through hole, and the lead screw is provided with a threaded hole. The connecting bolt passes through the third through hole and is threadedly connected to the threaded hole to detachably connect the guide and the lead screw.

[0012] As an optional technical solution, the second end of the guide is provided with a first tooth, and the lead screw is provided with a second tooth, the first tooth and the second tooth meshing together.

[0013] As an optional technical solution, both the tooth shape of the first tooth and the tooth shape of the second tooth are rectangular teeth.

[0014] As an optional technical solution, the guide component is also provided with a weight reduction structure.

[0015] This utility model also adopts the following technical solution:

[0016] An electric power steering system includes a motor and two steering tie rods. The electric power steering system also includes the transmission mechanism described above. The motor and the screw are connected by a drive mechanism, and the two ends of the lead screw are respectively connected to the two steering tie rods.

[0017] This utility model also adopts the following technical solution:

[0018] The vehicle includes the electric power steering system described above.

[0019] The beneficial effects of this utility model are:

[0020] This utility model discloses a transmission mechanism including a screw, a nut, a guide member, and a lead screw. The screw is used to connect to an external power source. The nut and screw are threaded together. The outer wall of the nut has a first mounting portion. The first end of the guide member has a second mounting portion. The first and second mounting portions are detachably connected by fasteners. The second end of the guide member is also detachably connected to the lead screw. This transmission mechanism, where the first mounting portion of the nut and the second mounting portion at the first end of the guide member are detachably connected by fasteners, and the second end of the guide member is also detachably connected to the lead screw, reduces stress concentration in the guide member, extends its service life, and facilitates disassembly and assembly of the guide member, nut, and lead screw. It also avoids the need to replace the nut, guide member, and lead screw simultaneously in case of guide member failure, effectively reducing costs.

[0021] This utility model also discloses an electric power steering system, which includes a motor, two steering tie rods, and a transmission mechanism as described above. The motor and a screw drive are connected, and the two ends of the lead screw are respectively connected to the two steering tie rods. This electric power steering system, by detachably connecting the guide member to the lead screw and nut, can reduce stress concentration on the guide member, extend the service life of the electric power steering system, reduce the number of parts to be replaced during maintenance, and lower the overall cost.

[0022] This utility model also discloses a vehicle that includes the above-mentioned electric power steering system, which can effectively avoid power steering failure caused by guide component failure, improve vehicle safety during driving, and reduce maintenance costs. Attached Figure Description

[0023] Figure 1 This is a partial structural schematic diagram of the electric power steering system according to an embodiment of the present utility model;

[0024] Figure 2 This is a schematic diagram of the transmission mechanism according to an embodiment of the present utility model;

[0025] Figure 3 This is a cross-sectional view of the transmission mechanism according to an embodiment of the present utility model;

[0026] Figure 4 yes Figure 3 A magnified view of part A in the image;

[0027] Figure 5 This is a schematic diagram of the connection between the nut and the guide component in an embodiment of this utility model;

[0028] Figure 6 This is a schematic diagram of the structure of the nut according to an embodiment of the present invention;

[0029] Figure 7This is a first structural schematic diagram of the guide component according to an embodiment of the present utility model;

[0030] Figure 8 This is a schematic diagram of the second structure of the guide component according to an embodiment of the present utility model.

[0031] In the picture:

[0032] 1. Transmission mechanism; 2. Steering tie rod;

[0033] 10. Screw;

[0034] 20. Nut; 21. First mounting base; 211. First through hole;

[0035] 30. Guide component; 31. Second mounting base; 311. Second through hole; 32. Plate-like structure; 321. Third through hole; 322. First toothed part; 33. Weight reduction structure; 331. Connecting frame; 332. Reinforcing rib; 34. Receiving cavity; 35. Limiting part;

[0036] 40. Lead screw; 41. Second tooth; 42. Threaded hole. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0038] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0040] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0041] like Figures 2 to 8 As shown, this embodiment provides a transmission mechanism 1, which includes a screw 10, a nut 20, a guide member 30, and a lead screw 40. The screw 10 is used to connect to an external power source. The nut 20 is threadedly connected to the screw 10. The outer wall of the nut 20 is provided with a first mounting portion. The first end of the guide member 30 is provided with a second mounting portion. The first mounting portion and the second mounting portion are detachably connected by fasteners. The second end of the guide member 30 and the lead screw 40 are detachably connected. Specifically, in this embodiment, the first mounting portion of the nut 20 and the second mounting portion at the first end of the guide member 30 are detachably connected by fasteners. The second end of the guide member 30 and the lead screw are also detachably connected. This reduces stress concentration in the guide member 30, extends its service life, and makes it easy to disassemble and assemble the guide member 30, the nut 20, and the lead screw 40. In the event of a failure of the guide member 30, the simultaneous replacement of the nut 20, the guide member 30, and the lead screw 40 can be avoided, effectively reducing costs.

[0042] Furthermore, such as Figures 5 to 8 As shown, the first mounting part has a first through hole 211, and the second mounting part has a second through hole 311. The fasteners include a fastening bolt and a fastening nut. The fastening bolt passes through the first through hole 211 and the second through hole 311 sequentially and is threadedly connected to the fastening nut, thus detachably connecting the first mounting part and the second mounting part. Specifically, in this embodiment, the first through hole 211 is machined on the first mounting part, and the second through hole 311 is machined on the second mounting part. The fastening bolt passes through the first through hole 211 and the second through hole 311 sequentially and is threadedly connected to the fastening nut. The threaded connection consists of the fastening bolt and the fastening nut. This arrangement ensures that the forces on both the first and second mounting parts are compressive, resulting in a more balanced force distribution between them. This avoids stress concentration in either the first or second mounting part, ensuring its service life.

[0043] In another embodiment, one of the first through hole 211 and the second through hole 311 can be set as a fastening threaded hole, and the fastening bolt can be threadedly connected to the fastening threaded hole, and the first mounting part and the second mounting part can also be connected, which will not be elaborated here.

[0044] Further, please refer to Figures 6 to 8 There are two first mounting parts, spaced apart on the outer wall of the nut 20; there are also two second mounting parts, spaced apart on the first end of the guide member 30. The two first mounting parts and two second mounting parts are arranged in a one-to-one correspondence. Specifically, in this embodiment, the two first mounting parts are symmetrically arranged about the axis of the nut 20, and the two second mounting parts are also symmetrically arranged about the axis of the nut 20. This arrangement improves the stability of the connection between the nut 20 and the guide member 30, and also helps to improve the force balance of the guide member 30, thereby facilitating the transmission of axial force and ensuring performance and service life.

[0045] Further, please refer to Figures 6 to 8 The first mounting part includes a plurality of first mounting seats 21, which are spaced apart along the axial direction of the nut 20. The second mounting part includes a plurality of second mounting seats 31, which are also spaced apart along the axial direction of the nut 20. The plurality of first mounting seats 21 and the plurality of second mounting seats 31 are staggered. Specifically, in this embodiment, the first mounting part includes two first mounting seats 21, each of which has a first through hole 211. The second mounting part includes three second mounting seats 31, each of which has a second through hole 311. Each first mounting seat 21 is sandwiched between two of the second mounting seats 31. All the first through holes 211 and all the second through holes 311 are coaxial. The fastening bolt passes through all the first through holes 211 and all the second through holes 311 and is threadedly connected to the fastening nut to detachably connect the nut 20 and the guide member 30. The fastening bolt and the fastening nut can fit the first mounting seat 21 and the second mounting seat 31 together. This arrangement can improve the connection stability of the guide member 30 and the nut 20, and can ensure the stability of the axial force transmitted by the nut 20 and the guide member 30, thereby improving the service life and ensuring the performance.

[0046] Specifically, in this embodiment, please refer to Figure 7 The guide member 30 is provided with a receiving groove that can accommodate at least part of the nut 20. The guide member 30 is also provided with a limiting part 35. The two limiting parts 35 are respectively provided at both ends of the receiving groove. The two limiting parts 35 can abut against the two end faces of the nut 20 respectively, thereby limiting the nut 20 in the receiving groove and ensuring the stability of the connection.

[0047] Specifically, in this embodiment, the second mounting base 31 is disposed on the side wall of the receiving groove at the end away from the lead screw 40.

[0048] Further, please refer to Figure 3 and Figure 4The guide member 30 has a third through hole 321 at its second end, and the lead screw 40 has a threaded hole 42. A connecting bolt passes through the third through hole 321 and is threaded into the threaded hole 42, thus detachably connecting the guide member 30 and the lead screw 40. Specifically, in this embodiment, the second end of the guide member 30 is a plate-like structure 32, and a concave surface is provided at a corresponding position on the lead screw 40. The third through hole 321 is formed in the plate-like structure 32, and the threaded hole 42 is formed in the concave surface. The concave surface and the plate-like structure 32 fit tightly together under the action of the connecting bolt, thereby allowing the guide member 30 and the lead screw 40 to be detachably connected. This design avoids the impact of interference fit on the guide member 30 and the lead screw 40, reduces the difficulty of disassembly and assembly, facilitates the recycling of parts, and reduces costs.

[0049] Further, please refer to Figure 3 and Figure 4 The guide member 30 has a first tooth 322 at its second end, and the lead screw 40 has a second tooth 41. The first tooth 322 and the second tooth 41 mesh with each other. Specifically, in this embodiment, by providing the first tooth 322 on the guide member 30 and the second tooth 41 on the lead screw 40, and by having the first tooth 322 and the second tooth 41 mesh with each other, the guide member 30 and the lead screw 40 are connected by teeth. This increases the effective connection length between the guide member 30 and the lead screw 40. Furthermore, the tooth shape of the tooth structure can directly withstand and transmit force, resulting in a clear force transmission path, reducing stress concentration, and significantly improving load-bearing capacity. At the same time, the tightness of the tooth meshing can effectively resist loosening caused by vibration or load, further ensuring the stability of the connection between the guide member 30 and the lead screw 40, and ensuring the effective transmission of axial force.

[0050] Furthermore, both the tooth profile of the first tooth portion 322 and the tooth profile of the second tooth portion 41 are rectangular teeth. Specifically, in this embodiment, both the tooth profile of the first tooth portion 322 and the tooth profile of the second tooth portion 41 are rectangular teeth, which have a compact structure, can achieve high-precision transmission, and can effectively transmit large torque, thereby improving service life.

[0051] In another embodiment, the first tooth portion 322 and the second tooth portion 41 may also adopt trapezoidal teeth, etc., which will not be described in detail here.

[0052] Further, please refer to Figure 7The guide member 30 is also provided with a weight-reducing structure 33. Specifically, in this embodiment, a weight-reducing structure 33 is also provided between the first end and the second end of the guide member 30. The weight-reducing structure 33 connects the first end and the second end. The specific structure of the weight-reducing structure 33 includes a connecting frame 331 and a reinforcing rib 332 disposed inside the connecting frame 331. The connecting frame 331 has a square structure, and the reinforcing rib 332 has a "V" shaped structure. The top of the reinforcing rib 332 is connected to the end face of the connecting frame 331 near the first end, and the two bottoms of the reinforcing rib 332 are connected to the two corners of the connecting frame 331 away from the first end. This arrangement can ensure the structural strength of the guide member 30 and reduce the weight of the guide member 30, thus ensuring its performance.

[0053] Specifically, in this embodiment, under the condition of maximum input torque of the motor, the maximum drag force of the lead screw 40 is 40000N. The maximum deformation of the lead screw 40 is taken as a constraint condition, and the lightest weight is taken as the optimization goal. The specific structure of the weight reduction structure 33 is obtained through topology optimization analysis.

[0054] In another embodiment, the top of the reinforcing rib 332 can be connected to the end face of the connecting frame 331 away from the first end, and the two bottoms of the reinforcing rib 332 can be connected to the two corners of the connecting frame 331 near the first end, which can achieve the same technical effect, and will not be described in detail here.

[0055] In another embodiment, the reinforcing rib 332 may also be W-shaped, which will not be described here.

[0056] like Figure 1 As shown, this embodiment also provides an electric power steering system, which includes a motor and two steering tie rods 2, as well as a transmission mechanism 1 as described above. The motor and the screw 10 are connected in a transmission connection, and the two ends of the lead screw 40 are respectively connected to the two steering tie rods 2. This electric power steering system, by detachably connecting the guide member 30 to the lead screw 40 and the nut 20, can reduce stress concentration on the guide member 30, extend the service life of the electric power steering system, reduce the number of parts to be replaced during maintenance, and lower the overall cost.

[0057] This utility model also provides a vehicle that includes the above-mentioned electric power steering system, which can effectively avoid power steering failure caused by the failure of the guide component 30, improve the safety of the vehicle during driving, and reduce maintenance costs.

[0058] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A transmission mechanism, characterised in that, The transmission mechanism comprises a screw rod (10), a nut (20), a guide piece (30) and a lead screw (40), the screw rod (10) is used for connecting an external power source, the nut (20) and the screw rod (10) are threadedly connected, an outer wall of the nut (20) is provided with a first mounting part, a first end of the guide piece (30) is provided with a second mounting part, the first mounting part and the second mounting part are detachably connected through a fastener, a second end of the guide piece (30) and the lead screw (40) are detachably connected.

2. The transmission mechanism according to claim 1, characterized in that The first mounting part is provided with a first through hole (211), the second mounting part is provided with a second through hole (311), the fastener comprises a fastening bolt and a fastening nut, the fastening bolt is sequentially threaded through the first through hole (211) and the second through hole (311) and is threadedly connected with the fastening nut, so as to detachably connect the first mounting part and the second mounting part.

3. The transmission mechanism of claim 2, wherein The first mounting part is provided with two, and the two first mounting parts are spaced apart on the outer wall of the nut (20); the second mounting part is provided with two, and the two second mounting parts are spaced apart on the first end of the guide piece (30), and the two first mounting parts and the two second mounting parts are correspondingly arranged.

4. The transmission mechanism of claim 3, wherein The first mounting part comprises a plurality of first mounting seats (21), and the plurality of first mounting seats (21) are spaced apart along the axis direction of the nut (20); the second mounting part comprises a plurality of second mounting seats (31), and the plurality of second mounting seats (31) are also spaced apart along the axis direction of the nut (20), and the plurality of first mounting seats (21) and the plurality of second mounting seats (31) are staggered.

5. The transmission mechanism of claim 1, wherein A third through hole (321) is arranged on the second end of the guide piece (30), a threaded hole (42) is arranged on the lead screw (40), and a connecting bolt is threadedly connected with the threaded hole (42) after being threaded through the third through hole (321), so as to detachably connect the guide piece (30) and the lead screw (40).

6. The transmission mechanism of claim 5, wherein A first tooth part (322) is arranged on the second end of the guide piece (30), and a second tooth part (41) is arranged on the lead screw (40), and the first tooth part (322) and the second tooth part (41) are engaged.

7. The transmission mechanism of claim 6, wherein The tooth shape of the first tooth part (322) and the tooth shape of the second tooth part (41) are both rectangular teeth.

8. A transmission according to any one of claims 1-7, characterised in that The guide piece (30) is further provided with a weight-reducing structure (33).

9. An electric power assisted steering system comprising an electric motor and two tie-rods (2), characterised in that, The electric power assisted steering system further comprises the transmission mechanism according to any one of claims 1-8, the motor and the screw rod (10) are drivingly connected, and both ends of the lead screw (40) are connected to the two steering tie rods (2) respectively.

10. Vehicle, characterized in that The vehicle comprises the electric power assisted steering system according to claim 9.

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