Dual motor power steering mechanism and system for an automobile

Abstract

The utility model relates to a double motor power-assisted steering mechanism and system for car, and the steering mechanism includes steering screw rod, power assembly and controller, the both ends of steering screw rod are connected knuckle, and the middle part of steering screw rod is equipped with first transmission part and second transmission part respectively, the power assembly includes first motor and second motor, the output of first motor is connected with first transmission part transmission, the output of second motor is connected with second transmission part transmission, the controller is connected with first motor and second motor electricity. Two sets of power-assisted system can independently run, improve the steering output force, and the redundant design of steering safety improves the safety of drive-by-wire intelligent driving.

Description

Technical Field

[0001] This utility model relates to the field of automotive steering technology, specifically to a dual-motor power steering mechanism and system for automobiles. Background Technology

[0002] Currently, electric power steering systems, assisted by an electric motor, are widely used in the automotive power steering system field. Different car models have significantly different loads, resulting in vastly different levels of assistance provided. A typical column-type electric power steering system (C-EPS) uses a single motor acting on the steering column to provide steering assistance through a worm gear. However, this method offers limited assistance due to limitations in the motor or steering shaft, resulting in a small range of assistance that cannot meet the needs of vehicles with higher loads. Therefore, the industry generally uses gear-type power steering systems (P-EPS) or rack-and-pinion power steering systems (R-EPS). However, both of these systems primarily use a single motor, which lacks safety redundancy and has limited rack force output. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a dual-motor power steering mechanism and system for automobiles, which addresses the increasingly high steering rack force requirements and safety requirements of electric vehicles.

[0004] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A dual-motor power steering mechanism for automobiles includes a steering screw, a power assembly, and a controller; The two ends of the steering screw are connected to steering knuckles, and the middle part of the steering screw is respectively provided with a first transmission part and a second transmission part; The power assembly includes a first motor and a second motor, wherein the output end of the first motor is connected to the first transmission unit, and the output end of the second motor is connected to the second transmission unit. The controller is electrically connected to the first motor and the second motor.

[0005] The beneficial effects of this utility model are: the two power steering systems can operate independently, which improves the steering output force, and the redundant design of steering safety improves the safety of drive-by-wire intelligent driving.

[0006] Based on the above technical solution, the present invention can be further improved as follows.

[0007] Furthermore, the output end of the first motor is connected to a worm gear assist unit, which is connected to the first transmission part, which is an inclined rack and pinion structure.

[0008] The beneficial effect of adopting the above-mentioned further solution is that the worm gear mechanism can achieve a very large reduction ratio, which means that the speed of the first motor is greatly reduced, while the output torque is significantly increased. This is the source of the assist effect—converting the small torque of the first motor into a huge thrust capable of pushing heavy objects or overcoming large resistance.

[0009] Furthermore, the worm gear assist unit includes a worm gear and a worm. One end of the worm is connected to the output end of the first motor for transmission. The worm gear meshes with the worm for transmission. A gear shaft is also connected to the center of one end of the worm gear. The gear shaft meshes with the inclined rack of the first transmission part for transmission.

[0010] The beneficial effect of adopting the above-mentioned further scheme is that it involves two stages of speed reduction and torque amplification. The first stage is a worm gear, and the second stage is a helical gear and steering screw, which is equivalent to a gear and rack, and also has the effect of speed reduction and torque amplification. The final thrust output to the steering screw is very large, achieving a powerful steering assist effect.

[0011] Furthermore, the gear shaft and the steering screw are inclined together, and the output end of the first motor is parallel to the steering screw.

[0012] The beneficial effect of adopting the above-mentioned further solution is that the helical teeth at the end of the gear shaft and the external thread of the steering screw engage at a certain angle. By transforming traditional sliding friction into efficient rolling friction, lower friction loss, higher transmission efficiency, more precise steering control, and longer service life are achieved while ensuring or even enhancing the power assist effect and self-locking safety.

[0013] Furthermore, the worm gear is connected to the output end of the first motor via a coupling.

[0014] The beneficial effect of adopting the above-mentioned further solution is that the coupling makes the worm gear assist unit and the first motor detachable, which facilitates later maintenance and replacement. In addition, the flexible coupling can also reduce the impact and torsional vibration generated by the first motor when starting, stopping or changing speed.

[0015] Furthermore, the output end of the second motor is connected to a ball screw assist unit, which is connected to the second transmission part, which has an external thread structure.

[0016] The beneficial effects of adopting the above-mentioned further solution are that the transmission efficiency of the ball screw assist unit is higher, and the rolling friction is used instead of the sliding friction of the ordinary screw, thereby reducing the friction coefficient and loss.

[0017] Furthermore, the ball screw assist unit includes a small pulley, a large pulley, and a synchronous belt. The synchronous belt is sleeved on the outer rings of the small pulley and the large pulley. The inner ring of the small pulley is fixed to the output end of the second motor. The inner ring of the large pulley is fixed with a screw nut. The screw nut engages with the external thread of the second transmission part through ball bearings.

[0018] The beneficial effect of adopting the above-mentioned further solution is that the small pulley is driven by the second motor, and the synchronous belt drives the large pulley. By selecting small and large pulleys with different numbers of teeth, a specific reduction ratio can be achieved, thereby increasing the output torque while reducing the speed.

[0019] Furthermore, a first limiting ring and a second limiting ring are respectively fixed at the ends of the first transmission part and the second transmission part that are far apart from each other, and the worm gear assist unit and the ball screw assist unit are both located between the first limiting ring and the second limiting ring.

[0020] The beneficial effect of adopting the above-mentioned further solution is that the axial displacement of the steering screw is limited by the first and second limit rings, which is converted into a limitation on the vehicle steering angle, so that the vehicle can turn within a fixed angle range.

[0021] Furthermore, it also includes a steering angle sensor, which is electrically connected to the controller and transmits the axial displacement data of the steering lead screw to the controller.

[0022] The beneficial effect of adopting the above-mentioned further solution is to achieve the purpose of closed-loop control of steer-by-wire by implementing monitoring of the steering angle signal of the steering angle sensor.

[0023] This utility model also provides a dual-motor power steering system for automobiles, which adopts a dual-motor power steering mechanism for automobiles as described in any of the above embodiments.

[0024] The beneficial effects of this invention are: reducing the risk of failure and improving safety by using dual redundant motors. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the dual-motor power steering mechanism for automobiles provided by this utility model; Figure 2 This is a front view of the dual-motor power steering mechanism for automobiles provided by this utility model. Figure 3 A schematic diagram of the worm gear assist unit provided by this utility model; Figure 4 This is a schematic diagram of the structure of the ball screw assist unit provided by this utility model.

[0026] The attached diagram lists the components represented by each number as follows: 1. Steering knuckle; 2. First motor; 3. Second motor; 4. Steering screw; 21. Worm gear assist unit; 22. Worm; 23. Worm gear; 24. Gear shaft; 25. Angle sensor; 26. Coupling; 31. Ball screw assist unit; 32. Small pulley; 33. Large pulley; 34. Synchronous belt; 35. Screw nut; 41. First transmission unit; 42. Second transmission unit; 43. First limiting retaining ring; 44. Second limiting retaining ring. Detailed Implementation

[0027] The principles and features of this utility model are described below. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0028] according to Figures 1 to 4 As shown, this utility model provides a dual-motor power steering mechanism for automobiles, including a steering screw 4, a power assembly, and a controller.

[0029] The two ends of the steering screw 4 are connected to the steering knuckle 1, and the middle part of the steering screw 4 is respectively provided with a first transmission part 41 and a second transmission part 42.

[0030] The power assembly includes a first motor 2 and a second motor 3. The output end of the first motor 2 is connected to the first transmission part 41, and the output end of the second motor 3 is connected to the second transmission part 42. The controller is electrically connected to the first motor 2 and the second motor 3.

[0031] This embodiment utilizes two independent power steering systems, enhancing steering output force and providing redundant design for steering safety, thus improving the safety of drive-by-wire intelligent driving. Compared to existing single-motor steering mechanisms, where the entire power steering system completely fails if the sole motor malfunctions (e.g., power failure, jamming, or electronic control unit failure), causing the vehicle to instantly lose power assistance—a highly dangerous situation for the driver—this embodiment allows the other motor to immediately take over and continue providing partial or full power assistance when one motor or its controller fails. The vehicle does not completely lose steering ability, giving the driver a valuable "limp home" capability, thereby minimizing the risk of accidents. The two motors can be designed as physically and electrically independent systems, creating true hardware redundancy and significantly improving the system's fault tolerance and overall reliability.

[0032] For heavy vehicles or high-performance sports cars, a single motor may not provide sufficient assist torque or power density. Dual-motor parallel drive easily achieves torque superposition, meeting the assist requirements under extreme conditions. Simultaneous start and acceleration of both motors allow for faster attainment of target speed and torque, resulting in a more responsive steering system, reduced lag, and improved vehicle handling agility.

[0033] In addition, the first motor 2 and the second motor 3 in this utility model are controlled independently by dual controllers. Both power assist systems can operate independently. When a single power assist system is used, one of the power assist systems is separated from the steering screw 4.

[0034] Based on the above technical solution, the present invention can be further improved as follows.

[0035] Preferably, in this embodiment, the output end of the first motor 2 is connected to a worm gear assist unit 21, which is drively connected to the first transmission part 41, which is an inclined rack and pinion structure. The worm gear assist unit 21 can achieve a large reduction ratio, which means that the rotational speed of the first motor 2 is significantly reduced, while the output torque is significantly increased. This is the source of the assist effect—converting the small torque of the first motor 2 into a huge thrust capable of pushing heavy objects or overcoming large resistance.

[0036] Preferably, in an embodiment, the worm gear assist unit 21 includes a worm gear 23 and a worm 22. One end of the worm 22 is connected to the output end of the first motor 2. The helical teeth on the worm gear 23 mesh with the thread of the worm 22. A gear shaft 24 is also connected to the axial center of one end of the worm gear 23. The gear shaft 24 is provided with helical teeth and meshes with the inclined rack of the first transmission part 41.

[0037] Specifically, according to Figure 3 As shown, the controller corresponding to the worm gear assist unit 21 controls the first motor 2 via the torque input from the torque sensor of the hand-feel unit. This motor, through the coupling 26, drives the worm 22 to rotate. The worm 22 drives the worm wheel 23, which rotates simultaneously with the gear shaft 24, which is fixedly connected to it. The gear shaft 24 drives the steering screw 4 to move laterally, thus outputting power through the steering knuckle 1.

[0038] This embodiment employs a two-stage reduction and torque amplification process. The first stage is the worm gear assist unit 21, and the second stage is the gear shaft 24 and steering screw 4, which, like a gear and rack, also contribute to reduction and torque amplification. The final thrust output to the steering screw 4 is very large, achieving a powerful assist effect.

[0039] Preferably, in this embodiment, the gear shaft 24 and the steering screw 4 are inclined together, and the output end of the first motor 2 is parallel to the steering screw 4. The helical teeth at the end of the gear shaft 24 mesh with the external thread of the steering screw 4 at a certain angle. By transforming traditional sliding friction into efficient rolling friction, lower friction loss, higher transmission efficiency, more precise steering control, and longer service life are achieved while ensuring or even enhancing the power assist effect and self-locking safety.

[0040] Preferably, in this embodiment, the worm gear 22 is connected to the output end of the first motor 2 via a coupling 26. The coupling 26 provides a detachable connection between the worm gear assist unit 21 and the first motor 2, facilitating future maintenance and replacement. Furthermore, the flexible coupling 26 can reduce the impact and torsional vibrations generated by the first motor 2 during startup, shutdown, or speed changes.

[0041] Furthermore, as is well known, there is a self-locking effect between the worm wheel 23 and the worm 22 in the worm gear assist unit 21. That is, the worm 22 can drive the worm wheel 23 to rotate, but the worm wheel 23 cannot drive the worm 22 to rotate. When the worm gear assist unit 21 in this invention is not in working state, it must be separated from the steering screw 4. In this embodiment, the gear shaft 24 and the worm wheel 23 are connected by a clutch. When the worm gear assist unit 21 is not in working state, the gear shaft 24 is separated from the worm wheel 23, and the gear shaft 24 can rotate freely relative to the worm wheel 23. When the worm gear assist unit 21 is in working state, the gear shaft 24 is engaged with the worm wheel 23, and the worm wheel 23 drives the gear shaft 24 to rotate.

[0042] Preferably, in the embodiment, the output end of the second motor 3 is connected to a ball screw assist unit 31, which is connected to the second transmission part 42. The second transmission part 42 has an external thread structure, and the ball screw assist unit 31 has high transmission efficiency.

[0043] Preferably, in an embodiment, the ball screw assist unit 31 includes a small pulley 32, a large pulley 33, and a synchronous belt 34. The synchronous belt 34 is sleeved on the outer rings of the small pulley 32 and the large pulley 33. The inner ring of the small pulley 32 is fixed to the output end of the second motor 3. The inner ring of the large pulley 33 is fixed with a screw nut 35. The screw nut 35 engages with the external thread of the second transmission part 42 through ball bearings.

[0044] Specifically, according to Figure 4As shown, the controller corresponding to the ball screw assist unit 31 controls the second motor 3 to rotate the small pulley 32 via the torque input from the torque sensor of the hand-feel unit. Then, the small pulley 32 rotates via the synchronous belt 34, which in turn drives the large pulley 33. The large pulley 33 is fixedly connected to the screw nut 35, which in turn drives the steering screw to move laterally. In this embodiment, selecting small pulleys 32 and large pulleys 33 with different numbers of teeth allows for a specific reduction ratio, thereby increasing the output torque while reducing the rotational speed.

[0045] Preferably, in this embodiment, a first limiting ring 43 and a second limiting ring 44 are fixed to the ends of the first transmission part 41 and the second transmission part 42 that are far apart from each other. The worm gear assist unit 21 and the ball screw assist unit 31 are both located between the first limiting ring 43 and the second limiting ring 44. The axial displacement of the steering screw 4 is limited by the first limiting ring 43 and the second limiting ring 44, which is converted into a limitation on the vehicle steering angle, so that the vehicle can turn within a fixed angle range.

[0046] Preferably, in this embodiment, a steering angle sensor 25 is further included. The steering angle sensor 25 is electrically connected to the controller and transmits the axial displacement data of the steering lead screw 4 to the controller. By monitoring the steering angle signal of the steering angle sensor 25, closed-loop control of the power steering by steer-by-wire is achieved.

[0047] This utility model also provides a dual-motor power steering system for automobiles, characterized in that it adopts a dual-motor power steering mechanism for automobiles as described in any of the above embodiments, thereby reducing the risk of failure and improving safety through dual redundant motors.

[0048] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., 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, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0051] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0052] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0053] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A dual-motor power steering mechanism for automobiles, characterized in that, Includes steering screw (4), power assembly and controller; The steering screw (4) is connected to the steering knuckle (1) at both ends, and the middle part of the steering screw (4) is provided with a first transmission part (41) and a second transmission part (42). The power assembly includes a first motor (2) and a second motor (3). The output end of the first motor (2) is connected to the first transmission part (41), and the output end of the second motor (3) is connected to the second transmission part (42). The controller is electrically connected to the first motor (2) and the second motor (3).

2. The dual-motor power steering mechanism for automobiles according to claim 1, characterized in that, The output end of the first motor (2) is connected to a worm gear assist unit (21), which is connected to the first transmission part (41) for transmission. The first transmission part (41) is an inclined rack and pinion structure.

3. The dual-motor power steering mechanism for automobiles according to claim 2, characterized in that, The worm gear assist unit (21) includes a worm gear (23) and a worm (22). One end of the worm (22) is connected to the output end of the first motor (2). The worm gear (23) meshes with the worm (22) for transmission. A gear shaft (24) is also connected to the center of one end of the worm gear (23). The gear shaft (24) meshes with the inclined rack of the first transmission part (41) for transmission.

4. The dual-motor power steering mechanism for automobiles according to claim 3, characterized in that, The gear shaft (24) is inclined to the steering screw (4), and the output end of the first motor (2) is parallel to the steering screw (4).

5. The dual-motor power steering mechanism for automobiles according to claim 4, characterized in that, The worm gear (22) is connected to the output end of the first motor (2) via a coupling (26).

6. A dual-motor power steering mechanism for automobiles according to any one of claims 2 to 5, characterized in that, The output end of the second motor (3) is connected to a ball screw assist unit (31), which is connected to the second transmission part (42) for transmission. The second transmission part (42) has an external thread structure.

7. The dual-motor power steering mechanism for automobiles according to claim 6, characterized in that, The ball screw assist unit (31) includes a small pulley (32), a large pulley (33), and a synchronous belt (34). The synchronous belt (34) is sleeved on the outer ring of the small pulley (32) and the large pulley (33). The inner ring of the small pulley (32) is fixed on the output end of the second motor (3). The inner ring of the large pulley (33) is fixed with a screw nut (35). The screw nut (35) engages with the external thread of the second transmission part (42) through ball bearings.

8. The dual-motor power steering mechanism for automobiles according to claim 7, characterized in that, The first transmission part (41) and the second transmission part (42) are respectively fixed with a first limiting ring (43) and a second limiting ring (44) at their ends that are far apart from each other. The worm gear assist unit (21) and the ball screw assist unit (31) are both located between the first limiting ring (43) and the second limiting ring (44).

9. The dual-motor power steering mechanism for automobiles according to claim 1, characterized in that, It also includes a steering angle sensor (25), which is electrically connected to the controller and transmits the axial displacement data of the steering screw (4) to the controller.

10. A dual-motor power steering system for automobiles, characterized in that, The dual-motor power steering mechanism for automobiles as described in any one of claims 1-9 is adopted.

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