阅读说明：本技术 电动助力转向器 (Electric power steering gear ) 是由 朱建军 张步勇 张翠平 于 2019-09-05 设计创作，主要内容包括：本发明属于电动方程式赛车技术领域,公开了一种电动助力转向器,包括齿条轴、齿轮和电机,齿条轴上设置有丝杠部和齿条部,丝杠部外周上设置有与丝杠部配合的滚珠螺母,丝杠部和滚珠螺母设置在中空的电机转轴内部,滚珠螺母与电机转轴通过平键传递扭矩,齿条部上设置有与齿轮配合的齿条；齿轮上设置有齿轮转速传感器；转向器壳体上设置有位移传感器,齿条轴上设置有用于与位移传感器配合的定位部,齿轮转速传感器的信号输出输出端和位移传感器的信号输出端与电机控制模块连接。本发明结构简单紧凑,可以广泛应用于电动方程式赛车领域。(The invention belongs to the technical field of electric formula racing cars and discloses an electric power steering gear which comprises a rack shaft, a gear and a motor, wherein a screw part and a rack part are arranged on the rack shaft; a gear rotating speed sensor is arranged on the gear; the steering gear comprises a steering gear shell, a rack shaft, a gear speed sensor, a motor control module and a rack shaft, wherein the steering gear shell is provided with a displacement sensor, the rack shaft is provided with a positioning part matched with the displacement sensor, and the signal output end of the gear speed sensor and the signal output end of the displacement sensor are connected with the motor control module. The invention has simple and compact structure and can be widely applied to the field of electric formula racing cars.)

1. The electric power steering gear is characterized by comprising a rack shaft (1), a gear (15) and a motor, wherein a screw part (17) and a rack part (18) are arranged on the rack shaft (1), a ball nut (12) matched with the screw part (17) is arranged on the periphery of the screw part (17), the screw part (17) and the ball nut (12) are arranged inside a hollow motor rotating shaft (13), the ball nut (12) and the motor rotating shaft (13) transmit torque through a flat key (11), and a rack matched with the gear (15) is arranged on the rack part (18); a gear rotating speed sensor (14) is arranged on the gear (15); be provided with displacement sensor (3) on the steering gear casing, be provided with on rack shaft (1) and be used for with displacement sensor (3) complex location portion (2), the signal output part of gear speed sensor (14) and the signal output part of displacement sensor (3) are connected with motor control module, motor control module is used for gear speed sensor (14) detect when the gear rotational speed is greater than the setting value, switch on motor power, still are used for controlling the rotation direction of motor shaft according to the positive and negative condition of displacement that displacement sensor (3) detected.

2. An electric power steering gear according to claim 1, characterized by further comprising a motor housing (4), wherein the motor is arranged in the motor housing (4), and both ends of the motor shaft (13) are connected with the motor housing (4) through bearings (7).

3. An electric power steering gear according to claim 2, wherein the motor shaft (13) is provided at both outer ends thereof with shoulder portions for mounting the bearings (7), and oil slingers (6) are provided between the bearings (7) and the shoulder portions of the motor shaft (13).

4. The electric power steering gear according to claim 2, further comprising a gear housing (16) and an end cover (9), wherein flanges are arranged at two ends of the motor housing (4), the flange at one end of the motor housing is connected with the end cover (9) through uniformly distributed screws, the flange at the other end of the motor housing is connected with the gear housing (16) through uniformly distributed screws, bosses for pressing the bearing (7) are arranged at one ends of the gear housing (16) and the end cover (9) close to the motor housing (4), a rack shaft supporting nut (8) is arranged at one end far away from the motor housing (4), through holes for allowing the rack shaft (1) to pass through are arranged inside the rack shaft supporting nut (8), and threads for connecting the gear housing (16) or the end cover (9) are arranged outside the rack shaft supporting nut.

5. An electric power assisted steering gear according to claim 1, characterized in that the motor is a three-phase brushless alternating current motor, the stator coils are three-phase double star-connected, the motor rotor is permanent magnet, and the motor coils (5) are arranged outside the motor shaft (13).

6. The electric power steering according to claim 1, wherein a limiting protrusion (19) matched with one end of the ball nut (12) is arranged inside the motor rotating shaft (13), a compression nut (10) matched with the other end of the ball nut (12) is further arranged on the motor rotating shaft (13), and the compression nut (10) is connected with the motor rotating shaft (13) through threads.

7. An electric power steering gear according to claim 1, characterized in that the positioning portion (2) is a cylindrical pin fixedly provided on the rack shaft (1).

8. An electric power steering gear according to claim 1, characterized in that the rack portion (18) and the pinion (15) are helical teeth.

9. An electric power steering gear according to claim 1, characterized in that the screw portion (17) is formed by threading a larger diameter portion of the rack shaft (2).

Technical Field

The invention belongs to the technical field of electric formula racing cars, and particularly relates to an electric power steering gear for an electric formula racing car for college students.

Background

The conventional steering gear of the formula car for college students mostly has no power-assisted system and is basically a gear rack steering gear. In the formula racing car for college students, 8-shaped surrounding, high-speed obstacle avoidance and the like are required in a competition, a racer needs to perform frequent steering operation for many times, and the racer without a power-assisted system needs to consume a large amount of physical strength in the steering of the racing car, so that the racer can feel fatigue more easily and the subsequent project performance is influenced to a great extent.

With the development of technology and the emergence of the electric equation game of college students, some steering assistance mechanisms are required to be added to improve the performance of the steering system of the racing car. Because the electric power-assisted steering system only needs electric power and does not need hydraulic pressure, compared with the hydraulic power-assisted steering system, a plurality of original parts are omitted, and therefore the electric power-assisted steering system is convenient to arrange and light in weight. And the event is an electric formula car, and can provide stable energy for the power-assisted motor.

Disclosure of Invention

In order to save physical power consumption of a racer caused by frequent steering operation in an electric equation competition project of college students and improve the competition result of the project, the invention overcomes the defects in the prior art and provides the electric power-assisted steering gear of the electric equation racer, which can provide auxiliary power required by steering through a steering power-assisted motor, thereby achieving the effects of light steering and saving the physical power of the racer.

In order to solve the technical problems, the invention adopts the technical scheme that: an electric power steering gear comprises a rack shaft, a gear and a motor, wherein a screw part and a rack part are arranged on the rack shaft, a ball nut matched with the screw part is arranged on the periphery of the screw part, the screw part and the ball nut are arranged inside a hollow motor rotating shaft, the ball nut and the motor rotating shaft transmit torque through a flat key, and a rack matched with the gear is arranged on the rack part; a gear rotating speed sensor is arranged on the gear; be provided with displacement sensor on the steering gear casing, the epaxial location portion that is used for with displacement sensor complex that is provided with of rack, gear speed sensor's signal output part and displacement sensor's signal output part are connected with motor control module, motor control module is used for gear speed sensor detects when the gear rotational speed is greater than the setting value, switch on motor power, still is used for controlling the direction of rotation of motor shaft according to the positive and negative condition of displacement that displacement sensor detected.

The electric power steering gear further comprises a motor shell, the motor is arranged in the motor shell, and two ends of a rotating shaft of the motor are connected with the motor shell through bearings.

And shoulder parts for mounting bearings are arranged at two ends of the outer part of the motor rotating shaft, and oil slingers are arranged between the bearings and the shoulder parts of the motor rotating shaft.

The utility model provides an electric power steering, still include gear housing and end cover, the both ends of motor casing are provided with the flange, and the flange of its one end is passed through the equipartition screw and is connected with the end cover, and the flange of the other end passes through the equipartition screw and is connected with gear housing, the one end that is close to motor casing on gear housing and the end cover all is provided with the bellying that is used for hold-down bearing, and the one end of keeping away from motor casing all is provided with rack shaft support nut, rack shaft support nut inside is provided with the through-hole that makes the rack shaft pass through, and the outside is provided with the screw.

The motor is a three-phase brushless alternating current motor, the stator coil is in three-phase double star connection, the motor rotor is in a permanent magnet type, and the motor coil is arranged on the outer side of the motor rotating shaft.

The motor rotating shaft is internally provided with a limiting bulge matched with one end of the ball nut, the motor rotating shaft is further provided with a compression nut matched with the other end of the ball nut, and the compression nut is connected with the motor rotating shaft through threads.

The positioning part is a cylindrical pin fixedly arranged on the rack shaft.

The rack portion and the gear are both helical teeth.

The lead screw part is formed by processing screw threads on the part with larger diameter on the rack shaft.

Compared with the prior art, the invention has the following beneficial effects:

1. the structure is simple and compact: the invention provides a power-assisted steering device which is simple in structure and light in weight, a power-assisted motor is concentric with a rack shaft, and a speed reducing mechanism is positioned in the steering power-assisted motor and is connected with the rack shaft, so that the space structure is optimized as much as possible, and the device is more compact; by arranging the gear rotating speed sensor and the displacement sensor, the power assisting direction can be controlled according to the motion condition of the rack shaft, and misoperation caused by vibration can be avoided;

2. the steering is more portable and flexible: the turning radius is usually smaller in the equation game of college students, so the speed is slower when turning, and the turning resistance required by turning is larger and the turning is heavier when the speed is low. When the electric power steering gear is arranged, a little steering force can be provided at low and medium speed, so that the electric power steering gear is lighter and more flexible in steering compared with a non-power steering gear;

3. can effectual saving racing driver physical power: in the undergraduate electric formula racing car, a series of operations such as 8-shaped surrounding, high-speed obstacle avoidance and the like are required to be carried out by a racer for carrying out frequent steering for many times, so that the racer can save more physical strength of the driver when driving the racing car provided with the electric power-assisted motor.

Drawings

Fig. 1 is a schematic structural diagram of an electric power steering apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic view of the internal structure of FIG. 1;

FIG. 3 is a schematic view of a portion of the structure of FIG. 2;

in the figure: 1-a rack shaft, 2-a positioning part, 3-a displacement sensor, 4-a motor shell, 5-a motor coil, 6-an oil deflector ring, 7-a bearing, 8-a rack support nut, 9-an end cover, 10-a compression nut, 11-a common flat key, 12-a ball nut, 13-a motor rotating shaft, 14-a gear rotating speed sensor, 15-a gear shaft, 16-a rack shell, 17-a screw rod part, 18-a rack part and 19-a limiting bulge.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 ~ 3, an embodiment of the present invention provides an electric power steering gear, which includes a rack shaft 1, a gear 15, and a motor, wherein a screw portion 17 and a rack portion 18 are disposed on the rack shaft 1, a ball nut 12 engaged with the screw portion 17 is disposed on an outer periphery of the screw portion 17, the screw portion 17 and the ball nut 12 are disposed inside a hollow motor shaft 13, the ball nut 12 and the motor shaft 13 transmit torque through a flat key 11, a rack engaged with the gear 15 is disposed on the rack portion 18, a gear rotation speed sensor 14 is disposed on the gear 15, a displacement sensor 3 is disposed on a steering gear housing, a positioning portion 2 engaged with the displacement sensor 3 is disposed on the rack shaft 1, a signal output end of the gear rotation speed sensor 14 and a signal output end of the displacement sensor 3 are connected to a motor control module, and the motor control module is configured to switch on a motor power supply when the gear rotation speed sensor 14 detects that a gear rotation speed is greater than a set value, and further configured to control a rotation direction of the motor shaft according to a positive/negative displacement detected by the displacement sensor 3.

Specifically, as shown in fig. 1 and 2, the electric power steering apparatus according to the embodiment of the present invention further includes a motor housing 4, a gear housing 16, and an end cover 9, the motor is disposed in the motor housing 4, and two ends of a rotating shaft 13 of the motor are connected to the motor housing 4 through bearings 7. The both ends of motor casing 4 are provided with the flange, and the flange of its one end is connected with end cover 9 through the equipartition screw, and the flange of the other end is connected with gear housing 16 through the equipartition screw, the one end that is close to motor casing 4 on gear housing 16 and the end cover 9 all is provided with the bellying that is used for hold-down bearing 7, and the one end of keeping away from motor casing 4 all is provided with rack shaft support nut 8, rack shaft support nut 8 is inside to be provided with the through-hole that makes rack shaft 1 pass through, and the outside is provided with the screw thread that is used for.

Specifically, as shown in fig. 3, both outer ends of the motor shaft 13 are provided with a shoulder portion for mounting the bearing 7, and the slinger 6 is provided between the bearing 7 and the shoulder portion of the motor shaft 13. The shoulder portion is formed by processing the end portion of the motor rotating shaft 13 inwards, the shoulder portion can limit the other side of the bearing 7, and the oil slinger 6 arranged between the shoulder portion and the bearing can seal the space at the two ends of the motor coil 5, so that lubricating grease at one side of the gear housing 16 and lubricating grease at the speed reducing portion formed between the ball nut 12 and the screw portion 17 can not enter the motor coil.

Specifically, in this embodiment, the motor is a three-phase brushless ac motor, the stator coil is connected in a three-phase double star shape, the motor rotor is a permanent magnet type, and the motor coil 5 is disposed outside the motor rotating shaft 13. The motor is very convenient to change the rotating direction, and the rapid steering power-assisted operation can be realized only by switching any two phases of a three-phase power supply. Therefore, the invention can simply control the positive and negative rotation of the motor, thereby realizing the power assistance in different steering directions.

Specifically, as shown in fig. 3, a limiting protrusion 19 matched with one end of the ball nut 12 is arranged inside the motor rotating shaft 13, a compression nut 10 matched with the other end of the ball nut 12 is further arranged on the motor rotating shaft 13, and the compression nut 10 is connected with the motor rotating shaft 13 through a thread. The ball nut is restrained by the restraining projection 19 and the compression nut 10 from both ends and fixed to the outer periphery of the screw portion 17, thereby realizing deceleration.

Specifically, as shown in fig. 3, the positioning portion 2 is a cylindrical pin fixedly provided on the rack shaft 1. The rack portion 18 and the gear 15 are each helical. The screw portion 17 is formed by machining a large diameter portion of the rack shaft 2.

The invention provides an electric power steering gear, which is characterized in that a motor rotating shaft 13 is processed into a hollow structure, and a speed reducing device formed by a ball nut and a screw part of a rack shaft is arranged in the hollow structure, so that the coaxiality of the motor rotating shaft 13 and the rack shaft 1 is ensured, errors are reduced, the radial size of the steering gear is not greatly changed after a power-assisted motor is installed, and the structure is more compact. In addition, the circulating ball type roller screw speed reducer matched with the inner shell of the motor rotating shaft 13 can reduce the rotating speed of the steering motor so as to obtain larger torque, and convert the rotation of the motor into the linear motion of the rack shaft 1. The tiny steel balls circularly roll in the smooth roller path to reduce the speed, and the power is transmitted to the rack shaft 1 to do linear motion, so that the two steering wheels are pushed to swing left and right to drive the racing car to steer. And because the steel ball is extremely small and the guide groove is extremely smooth, the transmission noise is extremely small, no idle stroke exists in the reverse direction, no self-locking phenomenon exists, and the efficiency is high.

The working process of the invention is as follows: when the vehicle needs to be steered, the steering device drives the gear shaft 16 to rotate, and the gear shaft drives the rack shaft to move along the axial direction through the gear, so that the vehicle is steered; the gear speed sensor 14 detects that a gear on the gear shaft 15 has a certain range of rotating speed, the motor control module is connected with a power-assisted motor power main switch, meanwhile, the displacement sensor 3 detects positive and negative displacement changes of the cylindrical pin 2, the motor control module can judge the moving direction of the rack shaft, so that the forward rotation or the overturn of the power-assisted motor is controlled, torque generated by the rotation of the power-assisted motor rotating shaft 13 is transmitted to the ball nut 12 through the common flat key 11, then the rotation of the power-assisted motor is converted into linear motion by the roller screw of the speed reducer, the speed is reduced, and finally the linear motion is transmitted to the screw part, namely the rack shaft 1, so that the rack shaft generates axial displacement, and the effect of certain power assistance in steering. Considering that the ground may sometimes generate certain impact on the wheels, and the impact may be transmitted through the steering mechanism, so that the steering gear rotates in a small amplitude, the gear rotation speed sensor 14 is arranged, so that the power supply of the motor is switched on when the gear rotation speed reaches a certain value, and misoperation caused by vibration can be avoided.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.