Large-angle steer-by-wire independent steering mechanism based on hub motor

Abstract

This invention discloses a large-angle steerable independent steering mechanism based on a hub motor, comprising a first power module, a second power module, and a steering execution module. The first power module consists of a first motor, a worm gear reducer, and a lead screw. The second power module consists of a second motor, a ball screw, a ball screw slider, a slewing bearing, and connecting components. The steering execution module includes a steering knuckle, a brake assembly, a hub motor, a tire hub, and a suspension assembly. This invention enables the wheels to achieve a turning angle of -45° to 45° via the first power module. For large-angle steering or lateral movement requirements, the second power module can steering the wheels to 90°, optimizing power distribution. Through the cooperation of the two power modules, this invention enables large-angle independent steering of steerable vehicles, allowing for straight driving, steering, diagonal driving, lateral movement, and stationary turning. It provides a feasible design for steerable independent steering structures, exhibiting excellent steering performance and practical value.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology, specifically relating to an independent steering mechanism based on a hub motor that enables large-angle steering. Background Technology

[0002] In recent years, with the rapid development of intelligent transportation and electric vehicle technologies, vehicle handling performance and agility have received increasing attention. Traditional vehicle steering systems mainly rely on mechanical connections and hydraulic power assist, which have certain limitations when facing high-angle steering or lateral movement. Especially in urban parking, narrow road conditions, and autonomous driving, vehicles need to have greater agility and maneuverability to improve driving safety and ease of operation.

[0003] Currently, many modern vehicles use electric power steering systems that are limited by the traditional steering angle range, making it impossible to meet the demands of high-angle steering and lateral vehicle movement. The urgent need is to solve the problem of optimizing vehicle power distribution and extending motor lifespan while achieving large-angle steering, improving driving safety and ease of handling.

[0004] CN115571219A discloses a large-angle double trailing arm suspension integrated steer-by-wire system. This system includes a steering motor, a reducer, wheel steering joints, and wheels, which are sequentially connected from top to bottom. The wheel steering joints are connected to the vehicle body via upper and lower trailing arms. While this technical solution can achieve wheel steering from -90° to 90°, its lateral and longitudinal dimensions are too large, and the entire structure is controlled by a single motor, significantly reducing the motor's lifespan.

[0005] CN113044109A discloses a four-wheel independent drive and independent steering chassis. Wheels are fixed to both sides of the frame via independent wheel carriers. Each wheel carrier connects to an independent steering unit. Each steering unit has a hub bearing sleeve, and an output flange is fixed above the hub bearing sleeve. A reducer is fixed to the output flange, and the input end of the reducer is connected to a steering motor. A hub shaft is located inside the hub bearing sleeve, with its upper end connected to the output end of the reducer and its lower end connected to the wheel carrier. The hub bearing sleeve is fixed to the frame on its respective side via a connector, allowing each wheel to rotate 360°. While this technical solution enables 360° wheel rotation, it is only suitable for high-chassis experimental vehicles, as no mechanism can be placed below the highest point of the wheels, limiting its applicability.

[0006] CN116461597A discloses a quick-detachable steer-by-wire independent steering mechanism, comprising: a steering actuator including an electric drive system, a steering motor, a motor retainer, and a bidirectional transmission flange; a steering transmission mechanism including a lock nut, a steering drive shaft, a thrust bearing, a drive shaft retaining bearing, and a bearing bracket; a body connection mechanism including a body connection plate; and an independent suspension connection mechanism including a suspension support plate and a suspension guide rod. Its longitudinal dimension is too large. Although it can achieve large-angle steering, the steering is completed by a single motor, reducing the motor's lifespan and negatively impacting the power distribution of electric vehicles. Summary of the Invention

[0007] To overcome the shortcomings of the existing technology, this invention provides a large-angle steer-by-wire independent steering mechanism based on a hub motor, which offers stable and reliable transmission and precise control of wheel steering angle. This mechanism enables the wheels to achieve steering angles from -45° to 45°, with a maximum steering angle of 90°. While achieving large steering angles, the mechanism maintains a minimum size. It better enables steering functions under various road conditions with large steering angles, thereby improving the vehicle's steering efficiency and stability.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] The large-angle independent steering mechanism based on hub motor of the present invention is characterized by being composed of a first power module, a second power module, and a steering execution module.

[0010] The first power module consists of a worm gear reducer, a first motor, and a lead screw. The first motor outputs power, and the worm gear reducer converts the circular motion of the motor output shaft into the linear motion of the lead screw. The second power module consists of a second motor, a flange-type support, a first ball screw support, a lead screw, a ball screw slider, a slewing bearing, a power module connector, and a second ball screw support. The second motor outputs power, and the ball screw converts the circular motion into the reciprocating linear motion of the ball screw slider, enabling the first power module, connected to the ball screw slider via the connector, to move linearly along the lead screw axis. A slewing bearing is provided between the connector and the ball screw slider. The first power module is bolted together with the connecting parts and the slewing bearing, and bolted together with the ball screw slider, allowing the first power module to rotate along the axis of the slewing bearing while achieving linear motion. The steering actuation module consists of a brake assembly, a hub motor, a tire hub, a suspension assembly, and a steering knuckle. The brake assembly is bolted to the hub motor, which is fixed inside the wheel hub tire. The suspension assembly is rigidly connected to the steering knuckle, which is connected to the lead screw via a ball joint. The steering of the wheel is achieved through the linear reciprocating motion of the lead screw and its linear and circular motion relative to the ball screw slider. The steering knuckle is fixed to the lower control arm, providing support for the entire steering mechanism.

[0011] The large-angle independent steering mechanism based on hub motor of the present invention is characterized by the following: In the first power module, the output shaft of the motor is connected to the worm gear reducer through a coupling. The motor, as the power output, converts the circular motion of the first motor output shaft into the linear motion of the lead screw through the worm gear reducer. The lead screw and the worm gear reducer are indirectly connected by a coupling. The worm gear reducer is fixed to the connecting part by bolts.

[0012] The large-angle independent steering mechanism based on a hub motor in this invention is characterized by the following: the second motor of the second power module is connected to the ball screw via a coupling; a flange-type support is bolted to the first ball screw support; the first and second ball screw supports are threaded to the vehicle frame; the ball screw is connected to the first and second ball screw supports; the ball screw slider is connected to the ball screw via a base-type connection; the ball screw slider has a threaded hole; the slewing bearing is bolted to the ball screw slider; and the slewing bearing is bolted to the connecting parts. This allows the first power module to rotate along the axis of the slewing bearing while simultaneously achieving linear motion with the ball screw slider.

[0013] In the steering actuation module, a ball joint is provided at one end of the steering knuckle, which is connected to the lead screw in the first power module using a ball joint pair, and can withstand a certain amount of positional displacement in the travel direction of the suspension assembly.

[0014] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0015] 1. This invention enables independent steering of the car wheels by setting up two power modules, which can optimize power distribution and extend the life of the power modules.

[0016] 2. This invention provides an independent steering mechanism with two power modules that can achieve a turning angle of -45° to 90°. Its steering is flexible and stable, and it can realize functions such as straight driving, turning, diagonal driving, lateral driving and turning in place, which greatly improves the operability and flexibility of the car.

[0017] 3. The first power module of this invention adopts a worm gear reducer, which has a compact structure, occupies little space, and its self-locking function can effectively protect the motor and improve the safety of the system; the second power module adopts a ball screw mechanism, which has the advantages of smooth movement, high precision, and high reliability, and can achieve precise transmission to ensure accurate control of the wheel rotation angle.

[0018] 4. The present invention uses a ball joint connection between the lead screw and the steering knuckle, which has high stability and can ensure smooth and reliable rotation of the connecting parts, avoiding loosening or unstable rotation; it can withstand large loads and rigid impacts, and can withstand a certain amount of positional displacement in the suspension travel direction. Attached Figure Description

[0019] Figure 1 This is an isometric view of the entire invention;

[0020] Figure 2 This is a partial isometric view of the second power module of the present invention;

[0021] Figure 3 This is a simplified structural diagram of the invention during normal driving.

[0022] Figure 4 This is a simplified structural diagram of the first extreme position of the present invention, i.e., when the wheel turns 45° to the right;

[0023] Figure 5 This is a simplified structural diagram of the first power module of the present invention at its extreme operating position, i.e., when the wheel turns 45° to the left.

[0024] Figure 6 This is a simplified structural diagram of the second extreme position of the present invention, i.e., when the wheel turns 90° to the left;

[0025] The following components are labeled in the diagram: 101 Second motor, 102 First ball screw support, 103 Screw, 104 Ball screw slider, 105 Connector, 106 First bolt, 107 Second ball screw support, 108 Flange support, 109 Slewing bearing, 110 Second bolt, 201 Worm gear reducer, 202 Third bolt, 203 First motor, 204 Screw, 301 Brake assembly, 302 Wheel hub motor, 303 Tire and wheel hub, 304 Suspension assembly, 305 Steering knuckle, 306 Lower control arm. Detailed Implementation

[0026] The large-angle independent steering mechanism based on a hub motor of the present invention will be further described below with reference to the accompanying drawings and through embodiments.

[0027] See Figure 1 , Figure 2 In this embodiment, the large-angle independent steering mechanism based on the hub motor includes a second motor 101, a first ball screw support 102, a screw 103, a ball screw slider 104, a connector 105, an M4 first bolt 106, a second ball screw support 107, a flange-type support 108, a slewing bearing 109, an M4 second bolt 110, a worm gear reducer 201, an M16 third bolt 202, a first motor 203, a screw 204, a brake assembly 301, a hub motor 302, a tire hub 303, a suspension assembly 304, a steering knuckle 305, and a lower control arm 306.

[0028] See Figure 1 For the first power module, the first motor 203 outputs power, which is transmitted to the worm gear through a coupling. The worm gear reducer 201 then converts the circular motion of the worm gear into the linear motion of the worm. The worm and the lead screw 204 are connected via a coupling, thus achieving the linear motion of the lead screw. The tail end of the lead screw is connected to the steering knuckle 305 of the steering actuator module via a ball joint. The linear motion of the lead screw controls the wheels to achieve a steering angle of -45° to 45°. At this time, the slider in the second motor module is in its initial position.

[0029] See Figure 1 , Figure 2For the second power module, after the wheel reaches a turning angle of 45° through the first power module, if a larger turning angle is still required, the first motor 203 stops working, and the second motor 101 starts working. The second motor 101 transmits power to the ball screw 103 through a coupling. The cooperation between the ball screw 103 and the ball screw slider 104 converts the circular motion of the ball screw 103 into the linear motion of the ball screw slider 104, driving the screw 204 to move linearly along the axial direction of the ball screw 103. At the same time, the connecting part 105 and the slewing bearing 109 are bolted together, and the slewing bearing 109 and the ball screw slider 104 are bolted together. The first power module can achieve linear motion along the axial direction of the ball screw 103 while rotating along the axis of the slewing bearing 109, thereby realizing the rotation of the wheel within the range of 45° to 90°. The two power modules work together to enable this steering mechanism to achieve a steering range of -45° to 90°.

[0030] like Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, point D is the concentric circle of the axis of slewing bearing 109, CE is the lead screw 204, and BC is the steering knuckle arm.

[0031] Figure 3 This is a simplified kinematic diagram of the linear motion of the present invention; Figure 4 This is a simplified structural diagram of the extreme position 1 of the present invention, that is, when the wheel rotates 45° clockwise, at which point the lead screw 204 is located at the farthest point of its stroke. Figure 5 This is a simplified diagram of the structure when the wheel rotates 45° counterclockwise, representing the extreme position of the first power module's movement. At this point, the lead screw 204 is at its closest point of travel. Figure 6 This is a simplified diagram of the structure at the extreme position 2 of the present invention, i.e., when the wheel rotates 90° counterclockwise. At this time, the lead screw 204 still maintains the closest position, and the ball screw slider is located at the position furthest from the second motor 101.

[0032] In the description of the invention, it should be understood that the terms "front", "back", "left", "right", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, 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 the invention.

[0033] The structural features of the present invention have been described in detail above with reference to the illustrations. The present invention is not limited to the scope of implementation shown in the illustrations. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall be within the protection scope of the present invention as long as they do not exceed the spirit covered by the specification and illustrations.

Claims

1. A large-angle steerable independent steering mechanism based on a hub motor, characterized in that: It consists of a first power module, a second power module, and a steering execution module; The first power module consists of a worm gear reducer (201), a first motor (203), and a lead screw (204). The first motor (203) outputs power, and the worm gear reducer (201) converts the circular motion of the motor output shaft into the linear motion of the lead screw (204). The second power module consists of a second motor (101), a flange-type support (108), a first ball screw support (102), a lead screw (103), a ball screw slider (104), and a slewing bearing (104). 09) The power module connector (105) and the second ball screw support (107) are used to form a power module connector (105). The second motor (101) outputs power and converts the circular motion into the reciprocating linear motion of the ball screw slider (104) through the ball screw (103). This realizes the linear motion of the first power module connected to the ball screw slider (104) through the connector (105) along the screw axis. At the same time, a slewing bearing (109) is provided between the connector (105) and the ball screw slider (104). The connecting part (105) and the slewing bearing (109) are bolted together, and the slewing bearing (109) and the ball screw slider (104) are bolted together, which allows the first power module to rotate along the axis of the slewing bearing (109) while achieving linear motion; the steering actuation module consists of a brake assembly (301), a hub motor (302), a tire hub (303), a suspension assembly (304), and a steering knuckle (305). The brake assembly (301) and the hub motor (104) are bolted together. 302) The hub motor (302) is fixed inside the hub tire (303) by bolt connection. The suspension assembly (304) is rigidly connected to the steering knuckle (305). The steering knuckle (305) is connected to the lead screw (204) through a ball joint. The steering of the wheel is achieved by the linear reciprocating motion of the lead screw (204) and its linear and circular motion relative to the ball screw slider (104). The steering knuckle (305) is fixed to the lower control arm (306) to support the entire steering mechanism.

2. The large-angle steer-by-wire independent steering mechanism based on a hub motor according to claim 1, characterized in that: In the first power module, the output shaft of the motor (203) is connected to the worm gear reducer (201) through a coupling. The motor (203) outputs power and converts the circular motion of the output shaft of the first motor (203) into the linear motion of the lead screw (204) through the worm gear reducer (201). The lead screw (204) and the worm gear reducer (201) are indirectly connected by a coupling. The worm gear reducer (201) is fixed to the connecting piece (105) by a third bolt (202).

3. The large-angle independent steering mechanism based on a hub motor according to claim 1, characterized in that: In the second power module, the second motor (101) is connected to the ball screw (103) via a coupling. A flange-type support (108) is bolted to the first ball screw support (102). The first ball screw support (102) and the second ball screw support (107) are threaded to the frame. The ball screw (103) is connected to the first ball screw support (102) and the second ball screw support (107). The ball screw slider (104) and the ball screw (103) are connected by a base. The ball screw slider (104) is provided with a threaded hole. The slewing bearing (109) and the ball screw slider (104) are connected by a second bolt (110). The slewing bearing (109) and the connecting piece (105) are fixedly connected by a first bolt (106). This allows the first power module to rotate along the axis of the slewing bearing (109) while moving linearly with the ball screw slider (104).

4. A large-angle steerable independent steering mechanism based on a hub motor according to claim 1, characterized in that: In the steering actuation module, a ball joint is provided at one end of the steering knuckle (305), which is connected to the lead screw (204) in the first power module using a ball joint pair, and can withstand a certain amount of positional offset in the travel direction of the suspension assembly (304).

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