Steering system and motor system

Abstract

To switch to a backup motor with a simple configuration.SOLUTION: A steering system 100 includes a first motor that drives a movement mechanism 110 that reciprocates an operation member 300, a spare second motor 202, a first gear 211 that is rotated by the first motor 201, a second gear 212 that is rotated by the second motor 202 and has a meshed region 213 and a non-meshed region 214, and a spare control device 250 that controls the second motor 202, wherein, in an initial state, the second motor 202 is in a stopped state and the first gear 211 and the second gear 212 are arranged in a non-meshed state, and the spare control device 250 includes an information acquisition unit 251 that acquires malfunction information indicating that a malfunction has occurred in the first motor 201, and a motor control unit 252 that rotates the second motor 202 to drive the movement mechanism 110 when the information acquisition unit 251 acquires the malfunction information.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a steering system and a motor system that are provided with redundancy so that operation can be continued using a spare motor in the event of a motor failure. [Background technology]

[0002] Patent Document 1 describes a technology for a steering system in which the steering wheel can be stored in a dashboard or the like, in which two motors are operated to move the steering wheel during normal operation, and if one motor fails, the steering wheel is moved to a predetermined position using only the other motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-54907 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology described in Patent Document 1, two motors move the steering wheel in different ranges, so if one motor fails, the other motor will only be able to move the steering wheel within its own range and will not be able to move the steering wheel over the entire range of movement. Also, because both motors operate together under normal circumstances, there is a possibility that both motors may fail at the same time.

[0005] The present invention has been made in consideration of the above-mentioned problems, and relates to a steering system and a motor system that ensures a normal range of operation by using a backup motor when the normally used motor fails. [Means for solving the problem]

[0006] One steering system of the present invention comprises a first motor that drives a moving mechanism that reciprocates an operating member between the driver's side and the front side of the vehicle, a second motor that functions as a backup for the first motor, a first gear that rotates by the driving force of the first motor, a second gear that rotates by the driving force of the second motor and has a meshing region that meshes with the first gear and a non-meshing region that does not mesh with the first gear, and a backup control device that controls the second motor, wherein in an initial state, the second motor is stopped and the first gear and the second gear are arranged in a non-meshing state, and the backup control device comprises an information acquisition unit that acquires malfunction information indicating that a malfunction has occurred in the first motor, and a motor control unit that, when the information acquisition unit acquires the malfunction information, rotates the second motor to drive the moving mechanism.

[0007] One motor system of the present invention includes a first motor, a second motor that functions as a backup for the first motor, a first gear that rotates by the driving force of the first motor, a second gear that rotates by the driving force of the second motor and has a meshing region that meshes with the first gear and a non-meshing region that does not mesh with the first gear, and a backup control device that controls the second motor, wherein in an initial state, the second motor is stopped and the first gear and the second gear are arranged in a non-meshing state, and the backup control device includes an information acquisition unit that acquires malfunction information indicating that a malfunction has occurred in the first motor, and a motor control unit that rotates the second motor when the information acquisition unit acquires the malfunction information. [Effects of the Invention]

[0008] When the first motor fails, the spare second motor can be operated to ensure a range of operation similar to that achieved by the first motor. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 2 is a perspective view showing the steering system in which the operating member is moved toward the driver. [Figure 2] FIG. 2 is a perspective view showing the steering system in which the operating member is moved toward the front of the vehicle. [Figure 3] FIG. 2 is a perspective view showing a motor system. [Figure 4] FIG. 10 is a plan view showing the positional relationship between the first gear and the second gear in an initial state. [Figure 5] 2 is a block diagram showing each functional unit of a standby control device 250. FIG. [Figure 6] FIG. 10 is a plan view showing a state in which the teeth of the first gear and the teeth of the second gear interfere with each other. [Figure 7] 4 is a flowchart showing a part of the operation flow of the steering system. [Figure 8] FIG. 10 is a plan view showing a first modified example of the second gear together with the first gear. [Figure 9] FIG. 10 is a plan view showing a first modification of the first gear together with the second gear. [Figure 10] FIG. 10 is a plan view showing a second modified example of the first gear and a second modified example of the second gear. [Figure 11] FIG. 10 is a plan view showing a third modified example of the second gear together with the first gear. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of a steering system and a motor system according to the present invention will be described with reference to the drawings. Note that the following embodiments are presented as examples to explain the present invention and are not intended to limit the present invention. For example, the shapes, structures, materials, components, relative positional relationships, connection states, numerical values, mathematical formulas, the content of each step in a method, and the order of each step shown in the following embodiments are merely examples and may include content not described below. Furthermore, while geometric expressions such as parallel and orthogonal may be used, these expressions do not indicate mathematical precision and include substantially allowable errors, deviations, and the like. Furthermore, expressions such as simultaneous and identical also include substantially allowable ranges.

[0011] The drawings are schematic diagrams in which emphasis, omission, or adjustment of proportions is appropriately made for the purpose of explaining the present invention, and differ from the actual shapes, positional relationships, and proportions. The X-axis, Y-axis, and Z-axis shown in the drawings represent Cartesian coordinates arbitrarily set for the purpose of explaining the drawings. In other words, the Z-axis is not necessarily an axis along the vertical direction, and the X-axis and Y-axis are not necessarily located within a horizontal plane.

[0012] In addition, in the following, multiple inventions may be collectively described as one embodiment, and some of the contents described below may be described as optional components related to the present invention.

[0013] FIG. 1 is a perspective view showing a steering system 100 in which an operating member 300 has been moved toward the driver. FIG. 2 is a perspective view showing the steering system 100 in which the operating member 300 has been moved toward the front of the vehicle. The steering system 100 is a device that can move the operating member 300 between the driver's side (X- side in the figure) and the front of the vehicle (X+ side in the figure). The steering system 100 according to this embodiment is mounted on a vehicle, such as a passenger car, bus, truck, construction machine, or agricultural machine, that can switch between a manual driving mode and an automatic driving mode. The type of steering system 100 is not limited. In this embodiment, the steering system 100 includes a movement mechanism 110 and a motor system 200. The steering system 100 also includes a steering mechanism (not shown) that steers the steered wheels in an automatic driving mode or by the driver's operation of the operating member 300. In a manual driving mode, for example, the steering system 100 reads the rotation angle of the operating member 300 with a sensor and steers the steered wheels based on the sensor signal, and in an automatic driving mode, the steering system 100 steers the steered wheels based on a signal transmitted from an ECU (Electronic Control Unit) for automatic driving provided in the vehicle. In the steering system 100, the operating member 300 and the steered wheels are not mechanically connected. Such a steering system is called, for example, a SBW (Steer By Wire) system.

[0014] The moving mechanism 110 is a device that can move the operating member 300 in at least one predetermined axial direction (the X-axis direction in the drawing). In this embodiment, the moving mechanism 110 moves the operating member 300 between a rear position on the driver's side (the X- side in the drawing) where the driver can operate the operating member 300 for driving, and a front position on the front side of the vehicle (the X+ side in the drawing) where the driver cannot reach the operating member 300 when in a driving position. The moving mechanism 110 includes a steering shaft 111, a fixed member 120, a movable member 130, a guide mechanism 140, and a moving device 150.

[0015] The steering shaft 111 is a rod-shaped member having an operating member 300 attached to the tip thereof, which is operated by the driver to steer the vehicle, and is rotatably supported by the movable member 130. In this embodiment, the steering shaft 111 is equipped with a rotation angle sensor 112, a reaction force generator 113, and the like.

[0016] The fixed member 120 is a member that is fixedly attached to a reinforcement, which is one of the structural members of the vehicle body. The manner in which the fixed member 120 is attached to the vehicle body is not limited. In the present embodiment, the fixed member 120 is attached in a state in which it is suspended from a reinforcement that is stretched across the width direction of the vehicle body. The cross-sectional shape of the fixed member 120 perpendicular to the movement direction of the movable member 130 relative to the fixed member 120 (the X-axis direction in the figure) is an L-shape rotated 90 degrees to the right.

[0017] A moving device 150 (see FIG. 2) is attached below the fixed member 120 (on the Z-side in the drawing) for moving the movable member 130 in the longitudinal direction of the vehicle relative to the fixed member 120. The type of moving device 150 is not particularly limited. In the present embodiment, the moving device 150 includes a feed screw 151 that extends in the movement direction of the movable member 130 (the X-axis direction in the drawing), and a movable nut 152 that meshes with the feed screw 151 and moves back and forth in the movement direction of the movable member 130 as the feed screw 151 rotates. The feed screw 151 is rotated by a motor system 200 attached to the fixed member 120, and can move the movable member 130 back and forth via the feed screw 151.

[0018] Movable member 130 is a member that rotatably supports steering shaft 111, and is a member that moves in a movement direction (X-axis direction in the figure) connecting a rear position and a front position relative to fixed member 120 by guide mechanism 140. Steering shaft 111 that holds operating member 300 is rotatably attached to movable member 130. In the case of this embodiment, the cross-sectional shape of movable member 130 perpendicular to the movement direction is an L-shape similar to that of fixed member 120 rotated 90 degrees to the right.

[0019] The guide mechanism 140 is a mechanism that guides the movable member 130 along a predetermined guide direction (the X-axis direction in the figure) between a predetermined rear position and a predetermined front position within the vehicle. In the present embodiment, the guide mechanism 140 includes two pairs of rails that extend in the guide direction and move relatively in the guide direction. The guide direction of the guide mechanism 140 coincides with the movement direction of the movable member 130 relative to the fixed member 120.

[0020] 3 is a perspective view showing motor system 200. Motor system 200 includes first motor 201, second motor 202, first gear 211, second gear 212, and standby control device 250. In the present embodiment, second motor 202 includes second reducer 222. Motor system 200 is a system that operates only first motor 201 under normal circumstances, and in the event of an abnormality in which a malfunction occurs in first motor 201, maintains first motor 201 in a free state (a state in which no force that resists torque input from the outside is generated) and operates second motor 202 to rotate the output shaft of first motor 201.

[0021] The first motor 201 is an actuator that drives the movement mechanism 110 to reciprocate the operating member 300 between the rear position shown in FIG. 1 and the forward position shown in FIG. 2. The type of the first motor 201 is not limited, but a servo motor can be exemplified. The first motor 201 enters a free state when the supply of power is cut off. Note that although the example shows a case in which the first motor 201 does not include a reducer, the first motor 201 may include a first reducer.

[0022] The second motor 202 is an actuator that functions as a backup for the first motor 201. Functioning as a backup means that the second motor 202 does not operate during normal operation of the first motor 201 and operates only when a malfunction occurs in the first motor 201. The type of the second motor 202 is not limited and may be the same type as the first motor 201 or a different type. In this embodiment, the second motor 202 is a different type from the first motor 201 and has inferior functionality compared to the first motor 201. Having inferior functionality means that at least one of the following conditions is satisfied: rotation control is not possible, the rated output is weak, and the rated rotation speed is slow. An example of the second motor 202 is a direct current (DC) motor. The second reducer 222 increases the output torque of the second motor 202 so that it approaches the output torque of the first motor 201. Although the example in which the second motor 202 includes the second reducer 222 has been described, the second motor 202 does not necessarily have to include the second reducer 222.

[0023] FIG. 4 is a plan view showing the positional relationship between the first gear 211 and the second gear 212 in an initial state. The first gear 211 is a gear that rotates by the driving force of the first motor 201. In the present embodiment, the first gear 211 is fixed to the first output shaft 203 of the first motor 201. The first gear 211 may contribute to driving the movement mechanism 110, but in the present embodiment, the first gear 211 does not contribute to driving the movement mechanism 110 and normally rotates idly without meshing with other gears. Although the first gear 211 is depicted as a spur gear in FIG. 3 and other figures, the type of the first gear 211 is not limited to a spur gear.

[0024] The second gear 212 is a gear that rotates by the driving force of the second motor 202, which operates when a malfunction occurs in the first motor 201. The second gear 212 has a meshing region 213 where teeth that mesh with the first gear 211 are present, and a non-meshing region 214 where there are no teeth and the second gear 212 does not mesh with the first gear 211. The meshing region 213 is a region of the second gear 212 that has teeth that mesh with the first gear 211. The non-meshing region 214 is a region of the second gear 212 that does not have teeth that mesh with the first gear 211. In the present embodiment, the second gear 212 is fixed to a second output shaft 204 (see FIG. 3 ) of the second motor 202. The second gear 212 is stationary and does not mesh with the first gear 211 during normal operation, from the initial state until a malfunction occurs in the first motor 201. In Figure 3 and other figures, the second gear 212 is depicted as a spur gear similar to the first gear 211, but the type of second gear 212 is not limited to a spur gear as long as it is a gear that can mesh with the first gear 211 as the second gear 212 rotates.

[0025] Although the number of teeth of the first gear 211 and the number of teeth of the second gear 212 (assuming that teeth exist in the non-meshing region 214) are illustrated as being the same, the number of teeth of the first gear 211 and the number of teeth of the second gear 212 may be different. In an initial state, the first gear 211 and the second gear 212 are disposed in a non-meshing state, and the second gear 212 is stopped and does not rotate because the second motor 202 is stopped. Note that the initial state refers to a state up until a malfunction occurs in the first motor 201. When the second motor 202 rotates and the second gear 212 rotates after leaving the initial state, the first gear 211 does not rotate when the non-meshing region 214 exists in the meshing region, but rotates when the meshing region 213 exists in the meshing region. In other words, the first gear 211 rotates intermittently due to the rotation of the second motor 202.

[0026] 5 is a block diagram showing the functional units of the standby control device 250. The standby control device 250 is a device equipped with a processor that controls the second motor 202 based on acquired information. The standby control device 250 is equipped with an information acquisition unit 251 and a motor control unit 252 as processing units realized by causing the processor to execute a standby control program.

[0027] The information acquisition unit 251 acquires malfunction information indicating that a malfunction has occurred in the first motor 201. The source from which the malfunction information is acquired is not limited, and the malfunction information may be acquired from one location or from two or more locations. For example, the malfunction information may be acquired from the first motor 201, or from a controller that controls the first motor 201. Furthermore, the malfunction information may be acquired from an ECU that controls the steering system 100, or the like.

[0028] When the information acquisition unit 251 acquires malfunction information, the motor control unit 252 rotates the second motor 202 to rotate the first gear 211, and rotates the output shaft 203 of the first motor 201 to drive the movement mechanism 110. In the present embodiment, the motor control unit 252 rotates (forward) the second motor 202 so that the operation member 300 moves to a rearward position where the driver in a driving posture can operate the operation member 300. Before rotating the second motor 202 forward, the motor control unit 252 controls the second motor 202 to rotate in the reverse direction. By controlling the second motor 202 to rotate in the reverse direction before rotating it forward, it is possible to avoid interference (clash) between the teeth of the first gear 211 and the teeth of the second gear 212 as shown in FIG. 6 . In other words, if the first gear 211 stops due to a malfunction of the first motor 201, depending on the position of the teeth of the first gear 211, interference may occur with the teeth of the second gear 212 that is rotating in the forward direction. However, by rotating the second gear 212 in the reverse direction before the forward rotation, the position of the teeth of the first gear 211 can be shifted, and interference with the teeth of the first gear 211 can be avoided when the second gear 212 subsequently rotates in the forward direction. Note that reverse and forward rotation may be repeated multiple times.

[0029] FIG. 7 is a flowchart showing part of the operation flow of the steering system 100. The steering system 100 uses the first motor 201 to move the operating member 300 until the information acquisition unit 251 of the standby control device 250 acquires malfunction information (S101, No). When the information acquisition unit 251 acquires malfunction information (S101, Yes), the motor control unit 252 repeats reverse and forward rotation of the second motor 202 a predetermined number of times as an initial operation (S102). The motor control unit 252 maintains the final forward rotation after the repeated reverse and forward rotations (S103), thereby moving the operating member 300 toward a rearward position where the driver in a driving posture can operate it. Note that, because the second gear 212 has a non-meshing region 214, the first gear 211 rotates intermittently. Accordingly, the operating member 300 also moves intermittently. Furthermore, the second motor 202 is a motor that functions as a backup and has a rated speed slower than that of the first motor 201, so the movement of the operating member 300 is slower than when the operating member 300 is moved by the driving force of the first motor 201.

[0030] When the information acquisition unit 251 acquires arrival information indicating that the operating member 300 has reached the rear position (S104, Yes), the motor control unit 252 stops the rotation of the second motor 202 (S105). This ends the control of the standby control device 250. At this stage, the operating member 300 has moved toward the driver, and the vehicle can be steered by the driver operating the operating member 300.

[0031] The present invention is not limited to the above-described embodiments. For example, the present invention may be embodied in another embodiment by arbitrarily combining the components described in this specification or by excluding some of the components. Furthermore, the present invention also includes various modifications that would occur to a person skilled in the art without departing from the spirit of the present invention, i.e., the meaning of the wording of the claims.

[0032] For example, as shown in Fig. 8, at least one of a pair of teeth arranged at both ends of the non-meshing region 214 of the second gear 212 may have a shorter tooth height than the other teeth of the second gear 212. For example, as shown in Fig. 8, by shortening the tooth height of the tooth on the intruding side of the non-meshing region 214 of the second gear 212, it is possible to avoid interference with the teeth of the first gear 211 regardless of the position of the teeth of the first gear 211.

[0033] Also, as shown in FIG. 9, some of the teeth of the first gear 211 may have a shorter tooth height than other teeth of the first gear 211.

[0034] As shown in FIG. 10, at least one of the tips of the teeth of the first gear 211 and the tips of the teeth of the second gear 212 (both in the case of FIG. 10) may be wedge-shaped and sharp.

[0035] Furthermore, the second gear 212 may have a plurality of non-meshing regions 214 arranged periodically, as shown in FIG.

[0036] The present invention also applies to the implementation of a program corresponding to each process executed by the standby control device 250. Of course, the present invention also applies to the implementation of a recording medium on which the program is recorded.

[0037] (summary) The steering system 100 of the first embodiment includes a first motor that drives a moving mechanism 110 that reciprocates an operating member 300 between the driver's side and the front side of the vehicle, a second motor 202 that functions as a backup for the first motor 201, a first gear 211 that rotates by the driving force of the first motor 201, a second gear 212 that rotates by the driving force of the second motor 202 and has a meshing region 213 that meshes with the first gear 211 and a non-meshing region 214 that does not mesh with the first gear 211, and a backup control device 250 that controls the second motor 202, and in an initial state, the second motor 202 is stopped and the first gear 211 and the second gear 212 are arranged in a non-meshing state, and the backup control device 250 includes an information acquisition unit 251 that acquires malfunction information indicating that a malfunction has occurred in the first motor 201, and a motor control unit 252 that, when the information acquisition unit 251 acquires the malfunction information, rotates the second motor 202 to drive the moving mechanism 110.

[0038] According to the first aspect, under normal circumstances, the first motor 201 is used to move the operating member 300, and in the event of an abnormality such as a malfunction of the operating member 300, the backup second motor 202 can be used to move the operating member 300 within the same range as under normal circumstances.

[0039] Since the second motor 202 is not normally used, deterioration due to use of the second motor 202 does not occur, and it is possible to reliably rotate the second motor 202 when the first motor 201 fails.

[0040] As the second motor 202 is operated only in an emergency, a motor with a slow operating speed or a motor with a loud operating noise can be used, and a small motor or a low-cost motor can be adopted as the second motor 202.

[0041] According to the steering system 100 of the first embodiment, it is possible to switch from the first motor 201 to the second motor 202 with a simple structure that combines two gears, and it is possible to achieve the above-mentioned effects.

[0042] The steering system 100 of the second embodiment includes the steering system of the first embodiment, and the motor control unit 252 reverses the second motor 202 at least once when the information acquisition unit 251 acquires malfunction information.

[0043] According to the second aspect, regardless of the stopping position of the first gear 211, it is possible to avoid a situation in which the teeth of the first gear 211 interfere with the teeth of the second gear 212, making it impossible to transmit rotation from the first gear 211 to the second gear 212.

[0044] The third embodiment of the steering system 100 includes the first embodiment or the second embodiment, and at least one of a pair of teeth located at both ends of the non-meshing region 214 of the second gear 212 has a shorter tooth height than the other teeth of the second gear 212.

[0045] According to the third aspect, regardless of the stopping position of the first gear 211, it is possible to avoid a situation in which the teeth of the first gear 211 interfere with the teeth of the second gear 212, making it impossible to transmit rotation from the first gear 211 to the second gear 212.

[0046] The steering system 100 of the fourth embodiment includes any of the first to third embodiments, and some of the teeth of the first gear 211 have a shorter tooth height than other teeth of the first gear 211.

[0047] According to the fourth aspect, regardless of the stopping position of the first gear 211, it is possible to avoid a situation in which the teeth of the first gear 211 interfere with the teeth of the second gear 212, making it impossible to transmit rotation from the first gear 211 to the second gear 212.

[0048] The steering system 100 of the fifth embodiment includes any of the first to fourth embodiments, and at least one of the tips of the teeth of the first gear 211 and the second gear 212 is wedge-shaped and sharp.

[0049] According to the fifth aspect, regardless of the stopping position of the first gear 211, it is possible to avoid a situation in which the teeth of the first gear 211 interfere with the teeth of the second gear 212, making it impossible to transmit rotation from the first gear 211 to the second gear 212. Note that although rigidity is considered to be poor due to the tooth structure, the first gear 211 and the second gear 212 mesh with each other during emergency avoidance, so the lack of rigidity is permissible.

[0050] The steering system 100 of the sixth embodiment includes any of the first to fifth embodiments, and the second gear 212 has a plurality of periodically arranged non-meshing regions 214.

[0051] According to the sixth aspect, the non-meshing region 214 appears in the meshing region between the first gear 211 and the second gear 212 at a relatively short period, so that the period in which the rotation of the first gear 211 stops is shortened, and the driver can feel that the operating member 300 is moving smoothly.

[0052] The motor system 200 of the seventh aspect includes a first motor 201, a second motor 202 that functions as a backup for the first motor 201, a first gear 211 that rotates by the driving force of the first motor 201, a second gear 212 that rotates by the driving force of the second motor 202 and has a meshing region 213 that meshes with the first gear 211 and a non-meshing region 214 that does not mesh with the first gear 211, and a backup control device 250 that controls the second motor 202, wherein in an initial state, the second motor 202 is stopped and the first gear 211 and the second gear 212 are arranged in a non-meshing state, and the backup control device 250 includes an information acquisition unit 251 that acquires malfunction information indicating that a malfunction has occurred in the first motor 201, and a motor control unit 252 that rotates the second motor 202 when the information acquisition unit 251 acquires the malfunction information.

[0053] According to the seventh aspect, under normal circumstances, the first motor 201 is operated, and in the event of an abnormality such as a malfunction of the operating member 300, the backup second motor 202 is used to move the operating member 300 within the same range as under normal circumstances.

[0054] Since the second motor 202 is not normally used, deterioration due to use of the second motor 202 does not occur, and it is possible to reliably rotate the second motor 202 when the first motor 201 fails.

[0055] As second motor 202 is operated only in an emergency, a motor with a slow operating speed or a motor with a loud operating noise can be used, and a small motor or a low-cost motor can be adopted as second motor 202. This allows motor system 200 to be made smaller and lighter.

[0056] According to the motor system 200 of the seventh aspect, the above-mentioned effects can be achieved with a simple structure that combines two gears. [Industrial Applicability]

[0057] The present invention can be used in a system that has a backup motor that operates in the event of a main motor failure. [Explanation of symbols]

[0058] 100...Steering system, 110...Moving mechanism, 111...Steering shaft body, 112...Rotation angle sensor, 113...Reaction force generating device, 120...Fixed member, 130...Movable member, 140...Guide mechanism, 150...Moving device, 151...Screw, 152...Movable nut, 200...Motor system, 201...First motor, 202...Second motor, 203...First output shaft, 204...Second output shaft, 211...First gear, 212...Second gear, 213...Engagement region, 214...Non-engagement region, 222...Second reducer, 250...Backup control device, 251...Information acquisition unit, 252...Motor control unit, 300...Operation member

Claims

1. a first motor that drives a movement mechanism that reciprocates the operation member between the driver's side and the front side of the vehicle; a second motor serving as a backup for the first motor; a first gear that rotates by the driving force of the first motor; a second gear that rotates by the driving force of the second motor and has a meshing region that meshes with the first gear and a non-meshing region that does not mesh with the first gear; a standby control device for controlling the second motor; In an initial state, the second motor is stopped, and the first gear and the second gear are arranged in a non-meshing state; The standby control device an information acquisition unit that acquires malfunction information indicating that a malfunction has occurred in the first motor; a motor control unit that rotates the second motor to drive the moving mechanism when the information acquisition unit acquires defect information. Steering system.

2. The motor control unit When the information acquisition unit acquires malfunction information, the second motor is reversed at least once. The steering system of claim 1 .

3. At least one of a pair of teeth arranged at both ends of the non-meshing region of the second gear has a tooth height shorter than that of the other teeth of the second gear.

3. A steering system according to claim 1 or 2.

4. Some of the teeth of the first gear have a shorter tooth height than other teeth of the first gear.

3. The steering system of claim 2.

5. At least one of the tips of the teeth of the first gear and the second gear is wedge-shaped and sharp. The steering system of claim 1 .

6. The second gear is having a plurality of periodically arranged non-interlocking regions The steering system of claim 1 .

7. A first motor; a second motor serving as a backup for the first motor; a first gear that rotates by the driving force of the first motor; a second gear that rotates by the driving force of the second motor and has a meshing region that meshes with the first gear and a non-meshing region that does not mesh with the first gear; a standby control device for controlling the second motor; In an initial state, the second motor is stopped, and the first gear and the second gear are arranged in a non-meshing state; The standby control device an information acquisition unit that acquires malfunction information indicating that a malfunction has occurred in the first motor; a motor control unit that rotates the second motor when the information acquisition unit acquires defect information. Motor system.

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