Electrically powered steering gear

Abstract

The application discloses an electric power steering gear, which comprises a driving motor, an input shaft, a torsion bar shaft, an output shaft and a controller. The input shaft is in driving connection with a steering wheel and the driving motor, and a plurality of first transmission gears are arranged on the input shaft. The torsion bar shaft is arranged with a plurality of second transmission gears and a plurality of electric control actuators. The first transmission gears and the second transmission gears are in one-to-one correspondence and engagement and constitute a plurality of gear sets, and the transmission ratios of the gear sets are different. The output shaft is in driving connection with the torsion bar shaft. The controller is in electrical connection with the driving motor. The controller can control the electric control actuators to engage the corresponding second transmission gears with the torsion bar shaft according to the signals obtained by sensors, so as to drive the output shaft to rotate, and the output shaft outputs corresponding torque values and rotation angle values, so that the power is not lost and the power of the motor is maximally utilized.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and in particular to an electric power steering system. Background Technology

[0002] Typically, an electric power steering (EPS) system includes a motor as the drive source and a torque sensor. The torque sensor outputs a sensor signal based on the torque of a torsion bar located in the middle of the steering shaft. Then, in response to the steering torque detected based on the sensor signal sent from the torque sensor, the torque in the motor is controlled so that an appropriate auxiliary force is applied to the steering system according to the steering torque. Therefore, it is necessary in an electric power steering system to detect the steering torque in a stable and highly accurate manner.

[0003] In related technologies, electric steering systems cannot properly match the corresponding torque, which reduces the lifespan of the motor and the overall steering system. The fixed gear ratio causes the output torque value to always be a large value. When the vehicle requires less steering force, it does not need excessive power, which wastes the power of the motor. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes an electric steering system in which the controller, based on signals acquired by sensors, controls the electronically controlled actuator to engage the corresponding second transmission gear with the torsion bar shaft, thereby driving the output shaft to rotate and output corresponding torque and angle values, thus ensuring that power is not lost and maximizing the utilization of the motor's power.

[0005] An electric steering system according to a first aspect of the present invention includes: a drive motor; an input shaft, which is tractively connected to a steering wheel and the drive motor, and the input shaft is provided with a plurality of first transmission gears; a torsion bar shaft, on which a plurality of second transmission gears and a plurality of electronically controlled actuators are provided, wherein the plurality of electronically controlled actuators and the plurality of second transmission gears correspond one-to-one, and the electronically controlled actuators are used to mesh the second transmission gears and the torsion bar shaft together, the plurality of first transmission gears and the plurality of second transmission gears meshing one-to-one and forming multiple gear sets, each gear set having a different transmission ratio; an output shaft, which is tractively connected to the torsion bar shaft; and a controller, which is electrically connected to the drive motor and the electronically controlled actuators, the controller being configured to: control the drive motor to start according to a steering angle signal, a torque signal, an engine speed signal, and a vehicle speed signal transmitted from the steering wheel end, the drive motor driving the plurality of first transmission gears on the input shaft to rotate, and the controller controlling the electronically controlled actuators to mesh the second transmission gears and the torsion bar shaft together to drive the output shaft to rotate.

[0006] According to an embodiment of the electric steering system of the present invention, the controller can control the electric actuator to mesh the corresponding second transmission gear with the torsion bar shaft based on the signal obtained by the sensor, so as to drive the output shaft to rotate and output the corresponding torque value and angle value, thereby ensuring that the power is not lost and maximizing the utilization of the motor power.

[0007] According to an embodiment of the present invention, the electric steering system has three sets of gears.

[0008] According to an embodiment of the present invention, the transmission ratios of the three sets of gears are i1, i2 and i3, respectively, and i1, i2 and i3 satisfy the following relationships: 22.5≤i1≤23.5, 19.5≤i2≤21.5, 17.5≤i1≤18.5.

[0009] According to some embodiments of the present invention, the controller has a power assist mode, in which the controller is further configured to: transmit a torque signal, a vehicle speed signal and an angle signal to the controller, the controller obtains a power assist torque value based on the steering wheel angle value, the torque value and the vehicle speed signal, and sends the power assist torque value to the drive motor, the drive motor outputs a corresponding power assist torque value.

[0010] According to some embodiments of the present invention, the controller has a return-to-center mode, and in the return-to-center mode the controller is further configured to: transmit torque signal, vehicle speed signal and angle signal to the controller, the controller obtains return-to-center torque value according to steering wheel angle value, torque value and vehicle speed signal, and sends the return-to-center torque value to drive motor, and drive motor outputs corresponding return-to-center torque value.

[0011] According to some embodiments of the present invention, the controller has a damping compensation mode. In the damping compensation mode, the controller is further configured to: transmit torque signal, vehicle speed signal and angle signal to the controller; the controller obtains damping compensation torque value according to steering wheel angle value, torque value and vehicle speed signal; and sends the damping compensation torque value to drive motor; the drive motor outputs the corresponding damping compensation torque value.

[0012] According to some embodiments of the present invention, the controller has a friction compensation mode. In the friction compensation mode, the controller is further configured to: transmit torque signal, vehicle speed signal and angle signal to the controller; the controller obtains friction compensation torque value according to steering wheel angle value, torque value and vehicle speed signal, and sends the friction compensation torque value to drive motor; the drive motor outputs the corresponding friction compensation torque value.

[0013] According to some embodiments of the present invention, the controller has an auxiliary compensation mode. In the auxiliary compensation mode, the controller is further configured to: transmit torque signal, vehicle speed signal and angle signal to the controller; the controller obtains auxiliary compensation torque value according to steering wheel angle value, torque value and vehicle speed signal; and sends auxiliary compensation torque value to drive motor; the drive motor outputs corresponding auxiliary compensation torque value.

[0014] According to some embodiments of the present invention, the controller has a protection mode, in which the controller is further configured to: transmit torque signal, vehicle speed signal and angle signal to the controller, the controller obtain a reduced assist signal according to the steering wheel angle value, torque value and vehicle speed signal, and the controller control the drive motor to output a corresponding torque value according to the reduced assist signal.

[0015] According to some embodiments of the present invention, the electric steering system further includes: an angle sensor and a torque sensor, the angle sensor and the torque sensor being disposed on the input shaft and electrically connected to the controller, the torque sensor being used to detect torque changes, and the angle sensor being used to detect the angle value of the steering wheel.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 This is a schematic diagram of the internal transmission structure of an electric steering system according to an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of the overall control logic of the electric power steering system according to an embodiment of the present invention;

[0020] Figure 3 A schematic diagram illustrating the basic functions of an electric power steering system according to an embodiment of the present invention.

[0021] Figure label:

[0022] 100. Electric power steering;

[0023] 10. Input shaft; 11. Torque sensor; 12. Angle sensor;

[0024] 20. Drive motor;

[0025] 30. First transmission gear;

[0026] 40. Torsion bar shaft; 41. Second transmission gear; 42. Electrically controlled actuator;

[0027] 50. Output shaft;

[0028] 60. Controller. Detailed Implementation

[0029] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0030] The following is for reference. Figures 1-3 An electric steering system 100 according to an embodiment of the present invention is described.

[0031] Combination Figures 1-2 As shown, the electric steering gear 100 includes: a drive motor 20, an input shaft 10, a torsion bar shaft 40, an output shaft 50, and a controller 60. The drive motor 20 can be controlled by the controller 60 to rotate the motor shaft. The rotation of the motor shaft drives the gear of the input shaft 10 to rotate, and the rotation of the gear of the input shaft 10 drives the output shaft to rotate.

[0032] Furthermore, the input shaft 10 is connected to the steering wheel and the drive motor 20 via a transmission connection. Multiple first transmission gears 30 are mounted on the input shaft. The controller 60 can receive steering angle signals, torque signals, engine speed signals, and vehicle speed signals from the steering wheel via the input shaft 10, thereby controlling the rotation of the drive motor 20. The first transmission gears 30 of the input shaft 10 are connected to the gears of the drive motor 20, and are also connected to the gears of the torsion bar shaft 40. The output shaft 50 will generate power assist and transmit it to the wheels. In addition, the multiple first transmission gears 30 are rigidly connected to the shaft of the input shaft 10. When the controller 60 controls the drive motor 20 to rotate, the gears of the drive motor 20 drive the first transmission gears 30 of the input shaft 10 to rotate, thereby driving the output shaft 50 to rotate. Specifically, there are three first transmission gears 30.

[0033] Furthermore, the output shaft 50 and the torsion bar shaft 40 are connected by a transmission, and the rotation of the torsion bar shaft 40 can drive the output shaft 50 to rotate.

[0034] In addition, the torsion bar shaft 40 is equipped with multiple second transmission gears 41 and multiple electronically controlled actuators 42. Each electronically controlled actuator 42 corresponds to one of the multiple second transmission gears 41, and the electronically controlled actuators 42 mesh with the second transmission gears 41 and the torsion bar shaft 40. Similarly, multiple first transmission gears 30 mesh with multiple second transmission gears 41, forming multiple gear sets, each with a different transmission ratio. In other words, the torsion bar shaft 40 is equipped with multiple second transmission gears 41 and multiple electronically controlled actuators 42. The number of electronically controlled actuators 42 is the same as the number of second transmission gears 41, and their positions correspond one-to-one. The electronically controlled actuators 42 can make the second transmission gears 41 mesh with the torsion bar shaft 40. The second transmission gears 41 selectively mesh with the torsion bar shaft 40. The electronically controlled actuators 42, based on information from the controller 60 and under the action of the locking structure, engage with the corresponding second transmission gear 41 to provide power assistance to the vehicle. The electronically controlled actuators 42 can be synchronizers. Multiple first transmission gears 30 correspond one-to-one with multiple second transmission gears 42, and the multiple first transmission gears 30 and multiple second transmission gears form multiple gear sets. Each gear set includes one first transmission gear 30 and one second transmission gear 42. Each gear set has a different transmission ratio so as to output different torques through the output shaft 50.

[0035] Furthermore, the controller 60 is electrically connected to the drive motor 20. The controller 60 is configured to: control the drive motor 20 to start based on the steering angle signal, torque signal, engine speed signal, and vehicle speed signal transmitted from the steering wheel; the drive motor 20 drives multiple first transmission gears 30 of the input shaft 10 to rotate; and the controller 60 controls the electronic actuator 42 to engage the second transmission gear 41 with the torsion bar shaft 40 to drive the output shaft 50 to rotate. In other words, the controller 60 can obtain signals, such as steering angle signals, torque signals, engine speed signals, and vehicle speed signals, through the input shaft 10 which is connected to the steering wheel, and process these signals to control the drive motor 20 to start. The drive motor 20 drives multiple first transmission gears 30 of the input shaft 10 to rotate. Based on the information processed by the controller 60, the electronic actuator 42 engages the corresponding second transmission gear with the torsion bar shaft 40, and the output shaft 50 is connected to the torsion bar shaft 40, thereby causing the output shaft 50 to rotate and output the corresponding torque and steering angle values.

[0036] Therefore, the controller 60 can control the electronic actuator 42 to mesh the corresponding second transmission gear 41 with the torsion bar shaft 40 based on the signals acquired by the sensor, so that the output shaft 50 outputs the corresponding torque and angle values. When the vehicle condition requires a large torque, the motor will provide a larger torque, sacrificing speed to obtain a larger torque. When the vehicle condition requires a smaller torque, the motor will provide a smaller torque, so that power is not lost and the power of the motor is maximized.

[0037] Combination Figure 1 As shown, there are three gear sets, that is, there are three first transmission gears 30 and three second transmission gears 42. The three first transmission gears 30 and the three second transmission gears 42 constitute three gear sets to output different torques through the output shaft 50.

[0038] Specifically, when the controller 60 detects a vehicle speed of 0-20 km / h and an engine speed of 0-1500 r / min, the electronic actuator 42 connects to one of the second transmission gears 41, and the output shaft 50 can output a third-level torque of 7300 N.m to meet the assistance required for stationary turning and low-speed driving; when the controller 60 detects a vehicle speed of 20-60 km / h and an engine speed of 1500-2000 r / min, the electronic actuator 42 connects to another second transmission gear 41, and the output shaft 50 can output a second-level torque of 5100 N.m to meet the assistance required for medium-speed driving; when the controller 60 detects a vehicle speed of 20-60 km / h and an engine speed of 2000-2500 r / min, the electronic actuator 42 connects to yet another second transmission gear 41, and the output shaft 50 can output a first-level torque of 3500 N.m to meet the assistance required for high-speed driving.

[0039] Furthermore, the transmission ratios of the three gear sets are i1, i2, and i3, respectively, and i1, i2, and i3 satisfy the following relationships: 22.5≤i1≤23.5, 19.5≤i2≤21.5, and 17.5≤i1≤18.5. In other words, the three gear sets have three transmission ratios: i1, i2, and i3. One gear set has a transmission ratio of i1, ranging from 22.5 to 23.5, allowing the output shaft 50 to output a third-level torque of 7300 N·m. Another gear set has a transmission ratio of i2, ranging from 19.5 to 21.5, allowing the output shaft 50 to output a second-level torque of 5100 N·m. Finally, a third gear set has a transmission ratio of i3, ranging from 17.5 to 18.5, allowing the output shaft 50 to output a first-level torque of 3500 N·m.

[0040] In addition, such as Figure 3As shown, the controller 60 has a power assist mode. In power assist mode, the controller 60 is further configured to transmit torque signals, vehicle speed signals, and angle signals to itself. The controller 60 obtains the power assist torque value based on the steering wheel angle value, torque value, and vehicle speed signal, and sends the power assist torque value to the drive motor 20. The drive motor 20 outputs the corresponding power assist torque value. Specifically, when the power mode is IGN_ON, under fault-free conditions, the electric steering gear 100 enters power assist mode. The driver applies torque to the steering wheel to turn it. The input shaft 10 is connected to the steering wheel. The sensor at the input shaft 10 detects the torque change and the current steering wheel angle value. Simultaneously, the sensor also detects vehicle speed information. The torque signal, vehicle speed signal, and angle signal are transmitted to the controller 60 for processing. The controller 60 selects a suitable power assist curve based on the current steering wheel angle value, the detected torque value, and the vehicle speed signal to calculate the required power assist torque value. This power assist torque value is then sent to the drive motor 20, which outputs the corresponding power assist torque value to provide power assist to the output shaft 50.

[0041] When the power mode is switched to a non-IGN_ON state or when there is a malfunction in the electric power steering 100, the electric power steering 100 exits the power assist mode.

[0042] And, according to Figure 3 As shown, the controller 60 also has a return-to-center mode. In the return-to-center mode, the controller 60 is also configured to transmit torque signal, vehicle speed signal and angle signal to the controller 60. The controller 60 obtains the return-to-center torque value according to the steering wheel angle value, torque value and vehicle speed signal, and sends the return-to-center torque value to the drive motor 20. The drive motor 20 outputs the corresponding return-to-center torque value. Specifically, when the power mode is IGN_ON, under the condition that the electric steering 100 is fault-free and the vehicle is traveling in the forward direction, the electric steering 100 enters the return-to-center mode. That is, when the vehicle is traveling in the forward direction, the driver applies torque to the steering wheel to turn the steering wheel. The input shaft 10 is connected to the steering wheel. The sensor at the input shaft 10 detects the torque change and the current angle value of the steering wheel. At the same time, the sensor also detects the vehicle speed signal. The torque signal, vehicle speed signal and angle signal are transmitted to the controller 60 for processing. The controller 60 calculates the return-to-center torque value based on the steering wheel angle value, torque value and vehicle speed signal, and sends the return-to-center torque value to the drive motor 20. The drive motor 20 outputs the corresponding return-to-center torque value, thereby applying the return-to-center torque to the output shaft 50.

[0043] When the power mode is switched to a non-IGN_ON mode, or when there is a malfunction in the electric steering 100, or when the vehicle speed is zero, the electric steering 100 exits the return-to-center mode.

[0044] Furthermore, such as Figure 3As shown, the controller 60 has a damping compensation mode. In this mode, the controller 60 is further configured to transmit torque, vehicle speed, and angle signals to itself. The controller 60 obtains the damping compensation torque value based on the steering wheel angle, torque, and vehicle speed signals, and sends this value to the drive motor 20. The drive motor 20 then outputs the corresponding damping compensation torque value. Specifically, when the power mode is IGN_ON, and the electric steering gear 100 is fault-free and the vehicle is traveling at high speed, the electric steering gear 100 enters the damping compensation mode. That is, when the vehicle is traveling at high speed, the sensor at the input shaft 10 detects the torque change and the current steering wheel angle. Simultaneously, the sensor also detects the vehicle speed signal. The controller transmits the torque, vehicle speed, and angle signals to the controller 60 for processing. The controller 60 calculates the damping compensation torque value based on the steering wheel angle, torque, and vehicle speed signals, and sends this value to the drive motor 20. The drive motor 20 then outputs the corresponding damping compensation torque value, applying the damping compensation torque to the input shaft 10.

[0045] When the power mode is switched to a non-IGN_ON mode, or when there is a malfunction in the electric steering 100, or when the vehicle speed is zero, the electric steering 100 exits the damping compensation mode.

[0046] Furthermore, such as Figure 3 As shown, the controller 60 has a friction compensation mode. In this mode, the controller 60 is further configured to transmit torque, vehicle speed, and angle signals to itself. The controller 60 obtains the friction compensation torque value based on the steering wheel angle, torque, and vehicle speed signals, and sends this value to the drive motor 20. The drive motor 20 then outputs the corresponding friction compensation torque value. Specifically, when the power mode is IGN_ON, and the electric steering gear 100 is fault-free, it enters the friction compensation mode. That is, the sensor at the input shaft 10 detects torque changes and the current steering wheel angle, while also detecting the vehicle speed signal. The controller transmits the torque, vehicle speed, and angle signals to the controller 60 for processing. The controller 60 calculates the friction compensation torque value based on the steering wheel angle, torque, and vehicle speed signals, and sends this value to the drive motor 20. The drive motor 20 then outputs the corresponding friction compensation torque value, applying the friction compensation torque to the input shaft 10.

[0047] When the power mode is switched to a non-IGN_ON state, or when there is a malfunction in the electric steering 100, the electric steering 100 exits the friction compensation mode.

[0048] In addition, such as Figure 3As shown, the controller 60 has an auxiliary compensation mode. In this mode, the controller 60 is further configured to transmit torque, vehicle speed, and angle signals to itself. The controller 60 obtains the auxiliary compensation torque value based on the steering wheel angle, torque, and vehicle speed signals, and sends this value to the drive motor 20. The drive motor 20 then outputs the corresponding auxiliary compensation torque value. Specifically, when the power mode is IGN_ON, after the electric steering gear 100 enters the friction compensation mode, the sensor at the input shaft 10 detects the torque change and the current steering wheel angle. Simultaneously, the sensor also detects the vehicle speed signal. The controller transmits the torque, vehicle speed, and angle signals to the controller 60 for processing. The controller 60 calculates the auxiliary compensation torque value based on the steering wheel angle, torque, and vehicle speed signals, and sends this value to the drive motor 20. The drive motor 20 outputs the corresponding auxiliary compensation torque value, applying the auxiliary compensation torque to the output shaft 50.

[0049] The controller 60 is further configured to: enter an auxiliary compensation mode when the vehicle deviates from its driving direction due to road conditions or crosswinds; and / or, enter an auxiliary compensation mode when the vehicle deviates from its driving direction due to suspension asymmetry, tire wear, or other reasons; and / or, enter an auxiliary compensation mode when the vehicle deviates from its driving direction during rapid acceleration or deceleration. Specifically, there are three auxiliary compensation modes: the first is a lateral disturbance compensation mode, the second is a deviation compensation mode, and the third is a torque compensation mode.

[0050] In simple terms, when the power mode is IGN_ON, under the condition that the electric steering 100 is fault-free and the vehicle is traveling in a straight line, the electric steering 100 enters the lateral interference compensation mode. That is, when the vehicle is traveling in a straight line, the vehicle may veer off course due to road bumps or crosswinds. The controller 60 can calculate the auxiliary compensation torque value based on signals such as yaw rate, vehicle speed, and steering wheel torque to make corrections, and send the auxiliary compensation torque value to the drive motor 20. The drive motor 20 outputs the corresponding auxiliary compensation torque value and applies the auxiliary compensation torque value to the output shaft 50.

[0051] At this time, when the power mode is switched to non-IGN_ON, or when the electric steering 100 malfunctions, or when the vehicle speed is zero, or when the steering wheel angle sensor does not change, the electric steering 100 exits the lateral interference compensation mode.

[0052] Alternatively, when the power mode is IGN_ON, if the electric steering 100 is fault-free and the vehicle is traveling in a straight line, the electric steering 100 enters the deviation compensation mode. That is, when the vehicle is traveling in a straight line, the vehicle may deviate from its driving direction due to reasons such as suspension asymmetry and tire wear. The controller 60 can calculate the auxiliary compensation torque value based on signals such as longitudinal acceleration, vehicle speed, and steering wheel angle to make corrections, and send the auxiliary compensation torque value to the drive motor 20. The drive motor 20 outputs the corresponding auxiliary compensation torque value and applies the auxiliary compensation torque value to the output shaft 50.

[0053] At this time, when the power mode is switched to non-IGN_ON, or when the electric steering 100 malfunctions, or when the vehicle speed is zero, the electric steering 100 exits the lane deviation compensation mode.

[0054] Alternatively, when the power mode is IGN_ON, if the electric steering 100 is fault-free and the vehicle accelerates or decelerates rapidly, the electric steering 100 enters torque compensation mode. That is, if the vehicle accelerates or decelerates rapidly, the driving direction may deviate. The controller 60 can calculate the auxiliary compensation torque value based on signals such as wheel speed difference and longitudinal acceleration to make corrections, and send the auxiliary compensation torque value to the drive motor 20. The drive motor 20 outputs the corresponding auxiliary compensation torque value and applies the auxiliary compensation torque value to the output shaft 50.

[0055] At this time, when the power mode is switched to non-IGN_ON, or when the electric steering 100 malfunctions, or when the longitudinal acceleration is zero, the electric steering 100 exits the torque compensation mode.

[0056] In addition, such as Figure 3 As shown, the controller 60 has a protection mode. In this mode, the controller 60 is further configured to transmit torque, vehicle speed, and angle signals to itself. The controller 60 then obtains a reduced power assist signal based on the steering wheel angle, torque, and vehicle speed signals. Based on this reduced power assist signal, the controller 60 controls the drive motor 20 to output a corresponding torque value. In other words, when the power mode is IGN_ON, after the electric steering gear 100 enters the protection mode, the sensor at the input shaft 10 detects the torque change and the current steering wheel angle. Simultaneously, the sensor also detects the vehicle speed signal. These signals are transmitted to the controller 60 for processing. The controller 60 obtains a reduced power assist signal based on the steering wheel angle, torque, and vehicle speed signals. Based on this reduced power assist signal, the controller 60 controls the drive motor 20 to output a corresponding torque value, applying torque to the output shaft 50.

[0057] The controller 60 is further configured to: enter a protection mode when the steering wheel is turned to near its limit; and / or, enter a protection mode when the power supply to the controller 60 is over-voltage or under-voltage; and / or, enter a protection mode when the steering angle and steering torque are abnormal. In other words, the protection mode includes three scenarios: the first is end-of-line protection or soft stop protection mode; the second is overload protection or stop-point protection mode; and the third is over-voltage or under-voltage protection mode.

[0058] Specifically, when the power mode is IGN_ON, if the electric steering 100 is fault-free and the steering wheel is turned to near its limit position, the electric steering 100 enters the end protection mode or soft stop protection mode. That is, when the steering wheel is turned to near its limit position, the controller 60 obtains a reduced assist signal based on the steering wheel angle value, torque value and vehicle speed signal. The controller 60 controls the drive motor 20 to output the corresponding torque value based on the reduced assist signal to avoid impact on the machinery.

[0059] At this time, when the power mode is switched to non-IGN_ON, or when the electric steering 100 malfunctions, or when the vehicle speed is zero, or when the steering wheel is turned to near its limit position, the electric steering 100 exits the end protection mode or soft stop protection mode.

[0060] Alternatively, when the power mode is IGN_ON, if the electric power steering 100 is fault-free but the steering angle and steering torque are abnormal, the electric power steering 100 enters an overload or stop protection mode. That is, when the steering angle and steering torque of the steering wheel are in an abnormal state, the controller 60 determines whether it has entered an overload state based on the steering wheel angle value, torque value and vehicle speed signal. If it has entered an overload state, the controller 60 obtains a reduce assist signal, sends the calculated torque value to the drive motor 20, and the drive motor 20 outputs the corresponding torque value to reduce assist and avoid damage to the motor caused by continuous high current output.

[0061] At this time, when the power mode is switched to non-IGN_ON, or when the electric steering gear 100 malfunctions, or when the steering angle and steering torque are normal, the electric steering gear 100 exits the overload or stop protection mode.

[0062] Alternatively, when the power mode is IGN_ON, if the electric steering gear 100 is fault-free and the power supply voltage of the controller 60 exceeds the limit, the electric steering gear 100 enters the overvoltage or undervoltage protection mode. That is, when the power supply voltage of the controller 60 is too high or too low, the controller 60 determines whether to enter the overvoltage or undervoltage state based on the power supply voltage status of the controller 60. If the overvoltage or undervoltage state is entered, the controller 60 obtains a reduced assist signal, sends the calculated torque value to the drive motor 20, and the drive motor 20 outputs the corresponding torque value to reduce the assist and avoid hardware damage.

[0063] At this time, when the power mode is switched to non-IGN_ON, or when there is a fault in the electric steering gear 100, or when the power supply voltage of the controller 60 is normal, the electric steering gear 100 exits the overvoltage or undervoltage protection mode.

[0064] Combination Figure 1 As shown, the electric steering system 100 further includes an angle sensor 12 and a torque sensor 11. The angle sensor 12 and torque sensor 11 are disposed on the input shaft 10 and are electrically connected to the controller 60. The torque sensor 11 is used to detect torque changes, and the angle sensor 12 is used to detect the angle value of the steering wheel. The angle sensor 12 and torque sensor 11 are located on the input shaft 10, and the input shaft 10 detects the angle value of the steering wheel and torque changes.

[0065] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this 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 this invention.

[0066] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are 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.

[0067] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An electric steering system (100), characterized in that, include: Drive motor (20); An input shaft (10) is connected to the steering wheel and to the drive motor (20) via a transmission connection. A plurality of first transmission gears (30) are provided on the input shaft (10). A torsion bar shaft (40) is provided with a plurality of second transmission gears (41) and a plurality of electric actuators (42). The plurality of electric actuators (42) and the plurality of second transmission gears (41) correspond one-to-one. The electric actuators (42) are used to mesh the second transmission gears (41) and the torsion bar shaft (40) together. The plurality of first transmission gears (30) and the plurality of second transmission gears (41) mesh one-to-one and form a plurality of gear sets. The transmission ratio of each gear set is different. Output shaft (50), the output shaft (50) and the torsion bar shaft (40) are connected in a transmission manner; A controller (60) is electrically connected to the drive motor (20) and the electronic actuator (42). The controller (60) is configured to: control the drive motor (20) to start according to the steering angle signal, torque signal, engine speed signal and vehicle speed signal transmitted from the steering wheel end; the drive motor (20) drives the plurality of first transmission gears (30) of the input shaft (10) to rotate; the controller (60) controls the electronic actuator (42) to mesh the second transmission gear (41) and the torsion bar shaft (40) together to drive the output shaft (50) to rotate. The controller (60) has a power assist mode. In the power assist mode, the controller (60) is also configured to transmit torque signal, vehicle speed signal and angle signal to the controller (60). The controller (60) obtains the power assist torque value according to the steering wheel angle value, torque value and vehicle speed signal, and sends the power assist torque value to the drive motor (20). The drive motor (20) outputs the corresponding power assist torque value.

2. The electric steering system (100) according to claim 1, characterized in that, The gear set consists of three sets.

3. The electric steering system (100) according to claim 2, characterized in that, The transmission ratios of the three gear sets are i1, i2 and i3, respectively. i1, i2 and i3 satisfy the following relationships: 22.5≤i1≤23.5, 19.5≤i2≤21.5, 17.5≤i3≤18.

5.

4. The electric steering system (100) according to claim 1, characterized in that, The controller (60) has a return-to-center mode. In the return-to-center mode, the controller (60) is also configured to transmit torque signal, vehicle speed signal and angle signal to the controller (60). The controller (60) obtains the return-to-center torque value according to the steering wheel angle value, torque value and vehicle speed signal, and sends the return-to-center torque value to the drive motor (20). The drive motor (20) outputs the corresponding return-to-center torque value.

5. The electric steering system (100) according to claim 1, characterized in that, The controller (60) has a damping compensation mode. In the damping compensation mode, the controller (60) is also configured to transmit torque signal, vehicle speed signal and angle signal to the controller (60). The controller (60) obtains the damping compensation torque value according to the steering wheel angle value, torque value and vehicle speed signal, and sends the damping compensation torque value to the drive motor (20). The drive motor (20) outputs the corresponding damping compensation torque value.

6. The electric steering system (100) according to claim 1, characterized in that, The controller (60) has a friction compensation mode. In the friction compensation mode, the controller (60) is also configured to transmit torque signal, vehicle speed signal and angle signal to the controller (60). The controller (60) obtains the friction compensation torque value according to the steering wheel angle value, torque value and vehicle speed signal, and sends the friction compensation torque value to the drive motor (20). The drive motor (20) outputs the corresponding friction compensation torque value.

7. The electric steering system (100) according to claim 1, characterized in that, The controller (60) has an auxiliary compensation mode. In the auxiliary compensation mode, the controller (60) is also configured to transmit torque signal, vehicle speed signal and angle signal to the controller (60). The controller (60) obtains auxiliary compensation torque value according to steering wheel angle value, torque value and vehicle speed signal, and sends auxiliary compensation torque value to drive motor (20). Drive motor (20) outputs corresponding auxiliary compensation torque value.

8. The electric steering system (100) according to claim 1, characterized in that, The controller (60) has a protection mode. In the protection mode, the controller (60) is also configured to transmit torque signal, vehicle speed signal and angle signal to the controller (60). The controller (60) obtains a reduced assist signal based on the steering wheel angle value, torque value and vehicle speed signal. The controller (60) controls the drive motor (20) to output a corresponding torque value based on the reduced assist signal.

9. The electric steering system (100) according to any one of claims 1-8, characterized in that, Also includes: An angle sensor (12) and a torque sensor (11) are provided on the input shaft (10) and electrically connected to the controller (60). The torque sensor (11) is used to detect torque changes, and the angle sensor (12) is used to detect the angle value of the steering wheel.

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