JP2023044603A - Steer-by-wire type steering device - Google Patents

Abstract

To provide a steer-by-wire type steering device which allows a driver to surely sense a situation where a direction of a steering object reaches a stroke end through a steering wheel when the direction reaches the stroke end.SOLUTION: A steer-by-wire type steering device includes: a motor shaft 16 rotated integrally with a steering wheel 1; an inner ring 20 connected to the motor shaft 16; an outer ring 21 which is provided so as to be fixed; an engagement element holder 25 which is supported so as to be movable between an engagement position where an engagement element 24 is engaged between the inner ring 20 and the outer ring 21, and an engagement release position where the engagement of the engagement element 24 is released; an electromagnet 27 for sucking an armature 26 by energization; and an operation conversion mechanism 28 which moves the engagement element holder 25 in a circumferential direction to the engagement position from the engagement release position according to movement of the armature 26.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steer-by-wire steering system that steers an object to be steered while the steering wheel and the object to be steered are mechanically separated from each other.

BACKGROUND ART A steer-by-wire system is known as a vehicle steering system that changes the direction of steered wheels of a vehicle in accordance with a driver's turning operation of a steering wheel. A steer-by-wire vehicle steering system includes a steering sensor that detects the amount of operation of a steering wheel, and a steering actuator that is mechanically separated from the steering wheel. It operates according to the amount of operation of the steering wheel detected by a sensor, and changes the direction of a pair of left and right steered wheels.

This steer-by-wire type vehicle steering system temporarily converts the operation amount of the steering wheel by the driver into an electric signal, and controls the operation of the steering actuator based on the electric signal. Optimizing the correspondence relationship between the operation amount of the steering wheel and the operation amount of the steering actuator according to the running state of the vehicle, such as adjusting the amount of change in the direction of the steered wheels according to the running speed of the vehicle. It is expected that it will be possible to improve the running stability and dynamic performance of the vehicle.

In a steer-by-wire vehicle steering system, a steering wheel that is rotatably operated by a driver is mechanically separated from a steering actuator that changes the direction of a pair of left and right steered wheels. Therefore, even when the driver operates the steering wheel while the vehicle is stopped and the direction of the steered wheels reaches its travel limit (stroke end), the driver can further rotate the steering wheel. be. Therefore, although the direction of the steered wheels has reached the stroke end, the driver does not notice that the direction of the steered wheels has reached the stroke end.

Therefore, Patent Document 1 proposes a steer-by-wire vehicle steering system that enables the driver to sense the situation through the steering wheel when the direction of the steered wheels reaches the end of the stroke. ing.

The vehicle steering system of Patent Document 1 has a reaction force motor that applies a steering reaction force to the steering wheel that is calculated based on vehicle speed, an operation amount of the steering wheel, and the like, and a reaction force controller that controls the reaction force motor. Then, the reaction force controller corrects and increases the magnitude of the steering reaction force generated by the reaction force motor when the direction of the steered wheels reaches the stroke end. As a result, the driver can sense through the steering wheel that the direction of the steered wheels has reached the end of the stroke.

International publication 2020/195226

As in Patent Document 1, when control is performed to correct and increase the magnitude of the steering reaction force generated by the reaction force motor when the direction of the steered wheels reaches the end of the stroke, the steering reaction force of the steering wheel remains unchanged. Since this only increases the force and does not prevent the rotation of the steering wheel, some drivers may not notice that the direction of the steered wheels has reached the end of the stroke, and may continue to turn the steering wheel. There is a risk of

In order to prevent such a situation, a method of increasing the size of the reaction force motor of the vehicle steering system disclosed in Patent Document 1 is conceivable. If the size of the reaction motor is increased, the magnitude of the steering reaction force that can be generated by the reaction motor also increases. It is possible to generate a large steering reaction force. However, increasing the size of the reaction motor reduces the space around it and increases the cost.

In addition to the steer-by-wire type vehicle steering system that steers the steerable wheels of the vehicle, the above-mentioned problem also occurs when a steer-by-wire type steering system is used, for example, when a rudder (such as an outboard motor) is provided at the stern of a ship. ) is also present in a steer-by-wire type ship steering system.

The problem to be solved by the present invention is to provide a steer-by-wire steering system that allows the driver to reliably perceive the situation through the steering wheel when the direction of the object to be steered reaches the stroke end. be.

In order to solve the above problems, the present invention provides a steer-by-wire steering system having the following configuration.
a steering wheel;
a steering sensor that detects the amount of operation of the steering wheel;
A steer-by-wire steering system having a steering actuator that is mechanically separated from the steering wheel and that changes the direction of a steered object according to the amount of operation of the steering wheel detected by the steering sensor. in
a shaft coupled to the steering wheel so as to rotate together with the steering wheel;
a fixed member fixedly provided so as not to rotate;
an inner ring connected to one of the shaft and the fixed member;
an outer ring connected to the other of the shaft and the fixed member;
an engaging element incorporated between the outer circumference of the inner ring and the inner circumference of the outer ring;
an engaging position for holding the engaging element and engaging the engaging element between the inner ring and the outer ring; and an engagement releasing position for disengaging the engaging element between the inner ring and the outer ring. an engaging element retainer supported movably in the circumferential direction between
an armature supported for axial movement;
an electromagnet that attracts and moves the armature in the axial direction when energized;
A steer-by-wire system, comprising: a movement conversion mechanism for circumferentially moving the engaging element retainer from one of the engaging position and the disengaging position to the other in accordance with the movement of the armature. steering gear.

With this configuration, by switching between energization and non-energization of the electromagnet, the engaging element is engaged between the inner ring and the outer ring from the disengagement position where the engagement of the engaging element between the inner ring and the outer ring is released. By moving the engaging element retainer to the engaging position, it is possible to switch from a steering unlocked state in which rotation of the steering wheel is permitted to a steering locked state in which rotation of the steering wheel is prevented. Here, when the engaging element retainer is moved to the engaging position, the engaging element physically engages between the inner ring and the outer ring, thereby preventing rotation of the inner ring. Rotation of the steering wheel that is engaged is reliably prevented. Therefore, by switching between energization and non-energization of the electromagnet when the direction of the object to be steered reaches the end of the stroke, the steering wheel is reliably prevented from rotating further, and the driver can tell the object to be steered through the steering wheel. direction reaches the stroke end.

The inner ring is connected to the shaft,
A configuration in which the outer ring is connected to the fixing member can be adopted.

In this case, the inner ring and the shaft allow relative rotation of the shaft with respect to the inner ring within a predetermined angular range, and prevent relative rotation of the shaft with respect to the inner ring beyond the predetermined angular range. connected with play in the predetermined angular range;
Between the inner ring and the shaft, when the inner ring and the shaft rotate relative to each other from the central position of the predetermined angular range, the inner ring and the shaft are oriented to the central position of the predetermined angular range. It is preferable to employ a configuration in which an elastic member is provided to apply a force.

In this way, when the direction of the object to be steered reaches the end of the stroke, the driver senses the situation through the steering wheel and suddenly turns the steering wheel in the opposite direction (the direction in which the object to be steered returns from the end of the stroke). In such a case, it is possible to prevent the steering wheel from locking and not moving.

That is, when the direction of the object to be steered reaches the end of the stroke, if the steering lock release state is switched to the steering lock state, the steering wheel cannot be rotated further, and the driver can turn the steering object through the steering wheel. senses that the direction of has reached the stroke end. Here, when the driver suddenly tries to turn the steering wheel in the opposite direction, it is necessary to immediately switch from the steering lock state to the steering lock release state in order to allow the rotation of the steering wheel. If the shaft that is connected to the wheel is connected to the inner ring without play so that it does not rotate relative to the inner ring at all, the operation to switch from the steering locked state to the steering unlocked state will not be done in time, and the driver will turn the steering wheel in reverse. You may not be able to rotate it. To solve this problem, when the above-described structure is adopted, the shaft is connected to the inner ring with play so as to allow relative rotation with respect to the inner ring within a predetermined angular range. When directional rotation is blocked, the steering wheel can be turned in the other of the forward and reverse directions by an angle corresponding to the play provided between the shaft and the inner ring. Therefore, when the driver senses through the steering wheel that the direction of the object to be steered has reached the end of the stroke and suddenly tries to turn the steering wheel in the opposite direction, the steering wheel is turned to allow the turning of the steering wheel. It is possible to secure time for switching from the locked state to the steering unlocked state, thereby preventing a situation in which the steering wheel is locked and does not move.

the shaft has a non-circular shank with a non-circular cross-section;
The inner ring has a non-circular hole portion that fits into the non-circular shaft portion with a circumferential gap,
A configuration can be adopted in which the elastic member is a plate spring that is circumferentially sandwiched between the non-circular shaft portion and the non-circular hole portion.

Also, the shaft has a non-circular shaft portion with a non-circular cross-section,
The inner ring has a non-circular hole portion that fits into the non-circular shaft portion with a circumferential gap,
The elastic member may be a compression coil spring that is compressed and incorporated between the non-circular shaft portion and the non-circular hole portion.

Also, the shaft has a non-circular shaft portion with a non-circular cross-section,
The inner ring has a non-circular hole portion that fits into the non-circular shaft portion with a circumferential gap,
The elastic member may be a torsion bar, one end of which is fitted into a fitting hole formed in the center of the shaft to prevent rotation, and the other end of which is prevented from rotating by the inner ring.

the fixing member is a tubular clutch case that houses the electromagnet and the armature;
A structure in which the outer ring is integrally formed with the clutch case can be adopted.

By doing so, the number of parts can be reduced and the manufacturing cost can be reduced.

The fixed member is a cylindrical clutch case that houses the electromagnet and the armature,
The clutch case is made of a non-magnetic material,
The outer ring may be formed separately from the clutch case and may be prevented from rotating by the clutch case.

In this way, since the clutch case is made of a non-magnetic material, when the electromagnet is energized, the magnetic flux generated by the electromagnet can be prevented from leaking into the clutch case, effectively attracting the armature. It becomes possible to Therefore, the size of the electromagnet and armature can be kept small, and space can be saved.

The fixed member is a cylindrical clutch case that houses the electromagnet and the armature,
the outer ring is formed separately from the clutch case and is prevented from rotating by the clutch case;
The electromagnet is arranged in the clutch case to face the outer ring in the axial direction,
The clutch case is provided with an electromagnet movement restricting portion that restricts movement of the electromagnet in one axial direction, and an outer ring movement restricting portion that restricts a movement range of the outer ring in the other axial direction,
A configuration may be employed in which an elastic spacer is incorporated between the outer ring and the electromagnet for urging them in the axial direction to move them away from each other.

By doing so, it is possible to keep the processing cost of the clutch case low. That is, when the outer ring and the electromagnet are arranged in the clutch case to face each other in the axial direction, a retaining ring for restricting the axial movement of the electromagnet in the direction toward the outer ring in order to fix the outer ring and the electromagnet in the axial direction; It is conceivable to employ a configuration in which snap rings are provided for restricting the axial movement of the outer ring in the direction toward the electromagnet, and snap ring grooves for mounting the respective snap rings are formed on the inner circumference of the clutch case. However, if this configuration is adopted, the cost of grooving the inner circumference of the clutch case is required. On the other hand, as described above, an elastic spacer is incorporated between the outer ring and the electromagnet to urge them in the axial direction away from each other. If the movement and the axial movement of the outer ring in the direction approaching the electromagnet are restricted, there is no need to form a groove for mounting the retaining ring on the inner circumference of the clutch case, which reduces the processing cost of the clutch case. It is possible to keep it low.

Any one of disc springs, wave springs, and compression coil springs can be employed as the elastic spacer.

Preferably, the elastic spacer is made of a non-magnetic material.

With this configuration, since the elastic spacer is made of a non-magnetic material, it is possible to prevent the magnetic flux generated from the electromagnet from leaking through the elastic spacer when the electromagnet is energized. It becomes possible to aspirate to Therefore, the size of the electromagnet and armature can be kept small, and space can be saved.

The outer ring is connected to the shaft,
A configuration may be adopted in which the inner ring is connected to the fixing member.

In this case, the inner ring and the fixed member allow relative rotation of the inner ring with respect to the fixed member within a predetermined angular range, and prevent relative rotation of the inner ring with respect to the fixed member beyond the predetermined angular range. are connected with play in the predetermined angular range,
Between the inner ring and the fixed member, when the inner ring and the fixed member rotate relative to each other from the central position of the predetermined angular range, the inner ring and the fixed member are positioned at the center of the predetermined angular range. It is preferable to employ a configuration in which an elastic member that biases toward the position is provided.

In this way, when the direction of the object to be steered reaches the end of the stroke, the driver senses the situation through the steering wheel and suddenly turns the steering wheel in the opposite direction (the direction in which the object to be steered returns from the end of the stroke). In such a case, it is possible to prevent the steering wheel from locking and not moving.

the fixing member is a tubular clutch case that houses the electromagnet and the armature;
The clutch case may employ a configuration formed of a non-magnetic material.

In this way, since the clutch case is made of a non-magnetic material, when the electromagnet is energized, the magnetic flux generated by the electromagnet can be prevented from leaking into the clutch case, effectively attracting the armature. It becomes possible to Therefore, the size of the electromagnet and armature can be kept small, and space can be saved.

further comprising a reaction force motor that applies a steering reaction force to the steering wheel;
the fixing member is a tubular clutch case that houses the electromagnet and the armature;
A configuration in which the clutch case is integrally formed with the motor case of the reaction motor can be adopted.

The motion conversion mechanism circumferentially moves the engaging element retainer from the disengaged position to the engaging position when the electromagnet is energized, and moves the engaging element retainer to the engaged position when the electromagnet is not energized. It is preferable to employ a configuration in which it is moved in the circumferential direction from the position to the disengagement position.

In this way, when the electromagnet is energized, the steering locked state is switched to the steering unlocked state, and when the electromagnet is de-energized, the steering unlocked state is switched to the steering locked state. Therefore, for example, when the power of the vehicle is turned off and the electromagnet is not energized, such as when the vehicle is parked, the steering lock state is entered in which the rotation of the steering wheel is prevented. A lock function can be added.

In the steer-by-wire steering system of the present invention, by switching between electrification and de-energization of the electromagnet, the engagement between the inner ring and the outer ring is changed from the disengagement position where the engagement of the engaging member between the inner ring and the outer ring is disengaged. It is possible to switch from a steering unlocked state in which rotation of the steering wheel is permitted to a steering locked state in which rotation of the steering wheel is prevented by moving the engaging element retainer to an engaging position where the engaging element is engaged. be. Here, when the engaging element retainer is moved to the engaging position, the engaging element physically engages between the inner ring and the outer ring, thereby preventing rotation of the inner ring. Rotation of the steering wheel that is engaged is reliably prevented. Therefore, by switching between energization and non-energization of the electromagnet when the direction of the object to be steered reaches the end of the stroke, the steering wheel is reliably prevented from rotating further, and the driver can tell the object to be steered through the steering wheel. direction reaches the stroke end.

1 is a diagram schematically showing a steer-by-wire steering system according to a first embodiment of the present invention; FIG. Cross-sectional view of the vicinity of the electromagnetic clutch unit in FIG. The figure which expands and shows the vicinity of the motion conversion mechanism of FIG. Cross-sectional view along the IV-IV line in Fig. 2 FIG. 2 is a diagram showing a second embodiment of the present invention corresponding to FIG. 2; Cross-sectional view along line VI-VI in Fig. 5 FIG. 2 is a diagram showing a third embodiment of the present invention corresponding to FIG. 1; Cross-sectional view of the vicinity of the electromagnetic clutch unit in FIG. FIG. 2 shows a fourth embodiment of the present invention corresponding to FIG. 2; Cross-sectional view along line XX in Fig. 9 A cross-sectional view showing a state in which the non-circular shaft shown in FIG. 10 rotates relative to the non-circular hole, and the rotation stopper surface on the outer circumference of the non-circular shaft is received by the inner surface of the non-circular hole. FIG. 10 is an exploded perspective view of the non-circular shaft portion, the non-circular hole portion, and the elastic member shown in FIG. 9 ; FIG. 10 shows a fifth embodiment of the present invention corresponding to FIG. 10; FIG. 2 is a diagram showing a sixth embodiment of the present invention corresponding to FIG. 2; Cross-sectional view along the XV-XV line in Fig. 14 FIG. 2 shows a seventh embodiment of the present invention corresponding to FIG. 2; Cross-sectional view along the XVII-XVII line in Fig. 16 Sectional view along line XVIII-XVIII in FIG. Sectional view along line XIX-XIX in FIG. Cross-sectional view along line XX-XX in Fig. 16 Cross-sectional view along line XXI-XXI in FIG. FIG. 21 is a view showing a state in which the flange portion of the first split cage and the flange portion of the second split cage approach each other in the axial direction and rotate relative to each other; A view showing a modification in which the outer ring and the clutch case shown in FIG. 16 are integrally formed. FIG. 2 shows an eighth embodiment of the present invention corresponding to FIG. 2; Enlarged cross-sectional view of the vicinity of the elastic spacer in FIG. FIG. 26 is a diagram showing another example of the elastic spacer of FIG. 25; FIG. 26 is a diagram showing still another example of the elastic spacer of FIG. 25; FIG. 2 shows a ninth embodiment of the present invention corresponding to FIG. 2; FIG. 2 shows the tenth embodiment of the present invention in correspondence with FIG. 2; Cross-sectional view along line XXX-XXX in FIG. FIG. 2 shows an eleventh embodiment of the present invention corresponding to FIG. 2;

FIG. 1 shows a steer-by-wire steering system according to a first embodiment of the present invention. This steering system converts the amount of operation of a steering wheel 1 by a driver into an electric signal, and controls a steering actuator 2 based on the electric signal, thereby changing the direction of a pair of left and right steerable wheels 3. It is a vehicle steering system of the system.

The steering system includes a steering wheel 1 steered by a driver, a steering shaft 4 connected to the steering wheel 1, a steering sensor 5 for detecting the amount of operation of the steering wheel 1, and a steering reaction force to the steering wheel 1. a reaction force motor 6; an electromagnetic clutch unit 7 that switches between a steering lock state that prevents the rotation of the steering wheel 1 and a steering lock release state that allows the rotation of the steering wheel 1 by switching between energization and non-energization; It has a steering actuator 2 and a control unit 8 which are mechanically separated from each other.

The steering shaft 4 is connected to the steering wheel 1 so as to rotate together with the steering wheel 1 when the steering wheel 1 is steered. A steering sensor 5 is attached to the steering shaft 4 . Examples of the steering sensor 5 include a steering angle sensor that detects the steering angle of the steering wheel 1 and a steering torque sensor that detects steering torque input to the steering wheel 1 by the driver.

The reaction motor 6 is an electric motor that generates rotational torque when energized. The reaction force motor 6 is connected to the end of the steering shaft 4 . The reaction force motor 6 applies a steering reaction force to the steering wheel 1 via the steering shaft 4 by inputting rotational torque to the steering shaft 4 .

The steering actuator 2 includes a steering shaft 10 , a steering shaft housing 11 , a steering motor 12 that moves the steering shaft 10 in the lateral direction of the vehicle, and a steering sensor 13 that detects the position of the steering shaft 10 . and The steering shaft 10 is supported by a steering shaft housing 11 so as to be movable in the lateral direction of the vehicle. The steered shaft housing 11 accommodates the central portion of the steered shaft 10 so that the left and right ends of the steered shaft 10 protrude from the steered shaft housing 11 .

The steering motor 12 and the steering sensor 13 are attached to the steering shaft housing 11 . Between the steered motor 12 and the steered shaft 10 is incorporated a motion conversion mechanism (not shown) that converts the rotation output by the steered motor 12 into linear motion of the steered shaft 10 . Both left and right ends of the steered shaft 10 are connected to a pair of left and right steered wheels 3 via tie rods 14, and when the steered shaft 10 moves in the axial direction, the directions of the pair of left and right steered wheels 3 change in conjunction with this movement. It's like

As shown in FIG. 2, the reaction motor 6 includes a motor case 15 and a motor shaft 16 protruding from the motor case 15 to the opposite side (lower side in the drawing) of the steering wheel 1 (see FIG. 1). have. The motor shaft 16 is rotatably supported by a rolling bearing (not shown) incorporated inside the motor case 15 . Further, the motor shaft 16 is connected to the steering shaft 4 (see FIG. 1) so as to rotate together with the steering wheel 1 and the steering shaft 4 (see FIG. 1). The motor case 15 is fixed to the vehicle body (not shown) so as not to rotate.

The electromagnetic clutch unit 7 includes an inner ring 20 connected to the motor shaft 16, an outer ring 21 fixed to the motor case 15, and a plurality of cam surfaces 22 formed on the outer circumference of the inner ring 20. (see FIG. 4), a cylindrical surface 23 formed on the inner circumference of the outer ring 21, engaging elements 24 incorporated between the cam surfaces 22 and the cylindrical surface 23, and engagements holding the engaging elements 24. A joint retainer 25, an armature 26 supported to be axially movable, an electromagnet 27 that attracts the armature 26 by energization and moves it in the axial direction, and an engaging element retainer 25 that rotates according to the movement of the armature 26. and a motion converting mechanism 28 for directionally moving.

The inner ring 20 is spline-fitted to the outer circumference of the motor shaft 16 . By this spline fit, the motor shaft 16 is connected to the inner ring 20 without play so as not to rotate relative to the inner ring 20 at all. Outer ring 21 is formed integrally with clutch case 29 . The clutch case 29 is a cylindrical member that collectively houses the constituent members of the electromagnetic clutch unit 7 (the inner ring 20, the engaging element 24, the engaging element retainer 25, the armature 26, the electromagnet 27, etc.). A radially outwardly extending flange portion 30 is formed at one axial end of the clutch case 29 , and the flange portion 30 is fixed to the axial end surface of the motor case 15 with bolts (not shown). A bearing 31 that rotatably supports the inner ring 20 is incorporated in the outer ring 21 .

Here, the clutch case 29 is fixed to the motor case 15 so as not to rotate even when the steering wheel 1 (see FIG. 1) is steered. Further, by forming the outer ring 21 integrally with the clutch case 29 , the outer ring 21 is connected to the clutch case 29 .

As shown in FIG. 4 , the cam surface 22 on the outer circumference of the inner ring 20 radially faces the cylindrical surface 23 on the inner circumference of the outer ring 21 . Between the cam surface 22 and the cylindrical surface 23, a wedge space is formed that gradually narrows from the center in the circumferential direction toward both ends in the circumferential direction.

A plurality of radially penetrating pockets 32 (see FIG. 2) are formed in the engaging element retainer 25 at intervals in the circumferential direction, and the engaging elements 24 are accommodated in the respective pockets 32 . The engaging element retainer 25 engages the engaging element 24 between the cam surface 22 and the cylindrical surface 23 by moving the engaging element 24 from the center in the circumferential direction of the cam surface 22 (see FIG. 4) in the circumferential direction. and an engagement release position where the engagement of the engagement element 24 between the cam surface 22 and the cylindrical surface 23 is released by moving the engagement element 24 to the center of the cam surface 22 in the circumferential direction. is supported so as to be movable in the circumferential direction with respect to the

As shown in FIG. 2 , the armature 26 is axially movably supported on the outer periphery of an inner ring shaft portion 33 integrally provided with the inner ring 20 . The armature 26 is a disk-shaped member made of a magnetic material (iron, silicon steel, etc.). The electromagnet 27 is arranged to face the armature 26 in the axial direction. The electromagnet 27 is fixed to the clutch case 29 so as not to move in either the axial direction or the circumferential direction. A separating spring 34 is installed between the armature 26 and the electromagnet 27 to urge the armature 26 in a direction away from the electromagnet 27 .

The electromagnet 27 has an annular field core 35 with a C-shaped cross section that opens axially toward the armature 26 and a solenoid coil 36 wound around the field core 35 . When the solenoid coil 36 is energized, a magnetic circuit is formed through the field core 35 and the armature 26 , and the armature 26 is attracted to the field core 35 . The clutch case 29 is formed with a through hole 38 through which a lead wire 37 for supplying electric power to the solenoid coil 36 passes. A rubber grommet 39 is attached to the through hole 38 to fill the gap between the inner circumference of the through hole 38 and the outer circumference of the lead wire 37 .

As shown in FIG. 3, the motion converting mechanism 28 is engaged with an intermediate plate 40 which is fixed to the armature 26 and fixed to the engaging element retainer 25 so as to be axially movable relative to the armature 26 . and a centering spring 41 that resiliently retains the dowel retainer 25 in the disengaged position.

An engagement projection 43 that engages with an engagement recess 42 formed in the engagement element retainer 25 is formed on the outer periphery of the intermediate plate 40 . The intermediate plate 40 is prevented from rotating by the engaging element retainer 25 by the engagement of the engaging protrusion 43 and the engaging recess 42 so as to move circumferentially together with the engaging element retainer 25 . Further, the intermediate plate 40 is formed with an axial projection 44 extending axially toward the armature 26 . The armature 26 is formed with an axial hole 45 into which the axial projection 44 of the intermediate plate 40 is axially slidably inserted. The intermediate plate 40 is axially movable with respect to the armature 26 by engagement between the axial projection 44 and the axial hole 45, and is prevented from rotating by the armature 26 so as to move circumferentially together with the armature 26. ing.

As shown in FIG. 4, the centering spring 41 includes a C-shaped annular portion 46 formed by winding a steel wire in a C-shape, and a pair of extension portions 47 extending radially outward from both ends of the C-shaped annular portion 46, respectively. Consists of The C-shaped annular portion 46 is fitted into a circular spring accommodating recess 48 formed in the axial end face of the inner ring 20 . The pair of extensions 47 are inserted into radial grooves 49 formed in the axial end face of the inner ring 20 so as to penetrate radially outward from the spring housing recess 48 .

The extending portion 47 of the centering spring 41 projects from the radially outer end of the radial groove 49 , and the projecting portion of the extending portion 47 from the radial groove 49 is formed in the retainer retainer 25 . It is inserted into the instrument groove 50 . The radial grooves 49 and the retainer grooves 50 are formed to have the same circumferential width. The extending portion 47 of the centering spring 41 is in contact with the inner surface of the radial groove 49 and the inner surface of the retainer groove 50, respectively, and the engaging element retainer 25 is engaged by the circumferential force acting on the contact portions. It is elastically held in the released position.

The electromagnetic clutch unit 7 shown in FIG. 2 is in an idling state in which the inner ring 20 can freely rotate with respect to the outer ring 21 when the electromagnet 27 is not energized. That is, when the electromagnet 27 is not energized, the armature 26 is separated from the electromagnet 27 by the urging force of the separation spring 34 , and the armature 26 becomes freely rotatable with respect to the electromagnet 27 . At this time, the engaging element retainer 25 is held at the disengaged position by the elastic restoring force of the centering spring 41. Therefore, even if the inner ring 20 is rotated, the cam surface 22 on the outer circumference of the inner ring 20 and the inner circumference of the outer ring 21 are displaced. The engaging element 24 is not engaged with the cylindrical surface 23 of the inner ring 20 and the motor shaft 16 can freely rotate in both forward and reverse directions.

On the other hand, when the electromagnet 27 is energized, the inner ring 20 is locked from rotating. That is, when the electromagnet 27 is energized, the armature 26 is attracted to the electromagnet 27 and the armature 26 is in frictional contact with the electromagnet 27 . At this time, when the inner ring 20 is rotated, the armature 26 that is in frictional contact with the electromagnet 27 is prevented from rotating by the engaging element retainer 25 via the intermediate plate 40, so that the rotation of the engaging element retainer 25 is restricted. The inner ring 20 rotates relative to the engaging element retainer 25 . As a result, the engaging element retainer 25 moves from the disengaged position to the engaged position against the elastic force of the centering spring 41, and the cam surface 22 on the outer circumference of the inner ring 20 and the cylindrical surface 23 on the inner circumference of the outer ring 21 are engaged. Since the engaging element 24 is engaged between , rotation of the inner ring 20 is prevented, and rotation of the motor shaft 16 connected to the inner ring 20 is prevented.

The reaction force motor 6, the electromagnetic clutch unit 7, and the steering motor 12 shown in FIG. An input side of the control unit 8 is electrically connected to the external sensor 51 , the steering sensor 5 and the turning sensor 13 . The external sensor 51 is a vehicle speed sensor or the like that detects the running speed of the vehicle. The reaction force motor 6 , the electromagnetic clutch unit 7 and the steering actuator 2 are electrically connected to the output side of the control section 8 .

The control unit 8 operates the steering motor 12 according to the amount of operation of the steering wheel 1 detected by the steering sensor 5 and the running condition (vehicle speed, etc.) of the vehicle detected by the external sensor 51, Control is performed to change the direction of the steered wheels 3 . At this time, the control unit 8 controls the reaction force motor 6 so as to generate a steering reaction force corresponding to the operation amount of the steering wheel 1 and the running condition of the vehicle.

Furthermore, based on the position of the steered shaft 10 detected by the steered sensor 13, the controller 8 determines whether or not the direction of the steered wheels 3 has reached the stroke end. When it is determined that the direction of the steered wheels 3 has not reached the stroke end, the electromagnet 27 (see FIG. 2) of the electromagnetic clutch unit 7 is de-energized, thereby engaging the engaging element retainer 25. Hold in release position. On the other hand, when it is determined that the direction of the steered wheels 3 has reached the stroke end, the electromagnet 27 (see FIG. 2) of the electromagnetic clutch unit 7 is energized to engage the engaging element retainer 25 from the disengaged position. to the aligned position.

In this steer-by-wire steering system, by switching between energization and non-energization of the electromagnet 27 shown in FIG. The engaging element holder 25 is moved to the engaging position where the engaging element 24 is engaged between the outer ring 20 and the outer ring 21, thereby allowing the rotation of the steering wheel 1 from the steering unlocked state in which the steering wheel 1 is allowed to rotate. It is possible to switch to a steering lock state that prevents Here, when the engaging element retainer 25 moves to the engaging position, the engaging element 24 physically engages between the inner ring 20 and the outer ring 21 to prevent the inner ring 20 from rotating. Moreover, the rotation of the steering wheel 1 connected via the motor shaft 16 and the steering shaft 4 shown in FIG. 1 is reliably prevented. Therefore, by switching between energization and non-energization of the electromagnet 27 when the direction of the steered wheels 3 reaches the end of the stroke, the steering wheel 1 is reliably prevented from rotating further, and the driver can move through the steering wheel 1. In addition, it is possible to reliably sense that the direction of the steered wheels 3 has reached the stroke end.

Further, in this steer-by-wire steering system, as shown in FIG. 2, the outer ring 21 is integrally formed with the clutch case 29, so the number of parts is small, and the manufacturing cost can be reduced.

5 and 6 show a second embodiment of the invention. The second embodiment differs from the first embodiment only in the configurations of the outer ring 21 and the clutch case 29, and the other configurations are the same. Therefore, parts corresponding to those in the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIG. 5 , the outer ring 21 is formed separately from the clutch case 29 . The clutch case 29 is made of a non-magnetic material (aluminum alloy, copper alloy, etc.). On the other hand, the outer ring 21 is made of steel. The outer ring 21 is fitted in a cylindrical clutch case 29 and is retained from the clutch case 29 by a retaining ring 52 attached to the inner circumference of the clutch case 29 . As shown in FIG. 6, a common key member 55 is fitted in a key groove 53 formed on the inner circumference of the clutch case 29 and a key groove 54 formed on the outer circumference of the outer ring 21. 21 is locked to a clutch case 29 . Here, the outer ring 21 is connected to the clutch case 29 by being prevented from rotating with a key member 55 .

When the configuration of the second embodiment is adopted, the clutch case 29 is made of a non-magnetic material, so that the magnetic flux generated from the electromagnet 27 is prevented from leaking to the clutch case 29 when the electromagnet 27 is energized. and the armature 26 can be efficiently sucked. Therefore, the sizes of the electromagnet 27 and the armature 26 can be kept small, and space can be saved.

7 and 8 show a third embodiment of the invention. In the third embodiment, in comparison with the second embodiment, the electromagnetic clutch unit 7 is mounted on the opposite side (lower side in the drawing) of the reaction motor 6 to the steering wheel 1 side. In contrast, in the third embodiment, the electromagnetic clutch unit 7 is attached to the reaction motor 6 on the side of the steering wheel 1 (upper side in the figure) in an upside down configuration. Other configurations are basically the same. Therefore, portions corresponding to those in the second embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIG. 8, the reaction motor 6 has a motor case 15 and a motor shaft 16 protruding from the motor case 15 toward the steering wheel 1 (see FIG. 7) (upward in the drawing).

The electromagnetic clutch unit 7 includes an inner ring 20 connected to the steering shaft 4, an outer ring 21 fixed to the motor case 15, and a plurality of cam surfaces 22 formed on the outer circumference of the inner ring 20. , a cylindrical surface 23 formed on the inner circumference of the outer ring 21, an engaging element 24 incorporated between each cam surface 22 and the cylindrical surface 23, and an engaging element retainer 25 that holds the engaging elements 24. , an armature 26 supported movably in the axial direction, an electromagnet 27 that attracts the armature 26 by energization and moves it in the axial direction, and a movement converter that moves the engaging element retainer 25 in the circumferential direction according to the movement of the armature 26. mechanism 28;

The inner ring 20 is connected to the steering shaft 4 via an inner ring shaft portion 33 integrally formed with the inner ring 20 . In the drawing, the inner wheel shaft portion 33 and the steering shaft 4 are integrally formed, but the inner wheel shaft portion 33 and the steering shaft 4 may be formed separately and connected so as to rotate together. .

In this electromagnetic clutch unit 7, as in the first embodiment, when the electromagnet 27 is not energized, the engaging element retainer 25 is held at the disengaged position. The engaging element 24 does not engage between the cam surface 22 on the outer circumference of the steering wheel 20 and the cylindrical surface 23 on the inner circumference of the outer ring 21, so that the inner ring 20 and the steering shaft 4 can freely rotate in both forward and reverse directions.

On the other hand, when the electromagnet 27 is energized, the engaging element retainer 25 moves from the disengaged position to the engaged position, and the gap between the cam surface 22 on the outer circumference of the inner ring 20 and the cylindrical surface 23 on the inner circumference of the outer ring 21 is maintained. , the rotation of the inner ring 20 is prevented, and the rotation of the steering shaft 4 connected to the inner ring 20 is also prevented.

Similarly to the first embodiment, the vehicle steering system of the third embodiment switches between energization and non-energization of the electromagnet 27 when the direction of the steered wheels 3 (see FIG. 7) reaches the stroke end. Further rotation of the steering wheel 1 (see FIG. 7) is reliably prevented, and the driver can reliably sense through the steering wheel 1 that the direction of the steered wheels 3 has reached the stroke end. can.

9 and 10 show a fourth embodiment of the invention. The fourth embodiment differs from the first embodiment only in the connection structure between the inner ring 20 and the motor shaft 16, and the rest of the configuration is the same. Therefore, portions corresponding to those in the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIG. 10, the motor shaft 16 has a non-circular shaft portion 60 with a non-circular cross-section. The inner ring 20 is formed with a non-circular hole portion 61 into which the non-circular shaft portion 60 of the motor shaft 16 is fitted with a circumferential gap. A rotation stopper surface 62 and an elastic member holding portion 63 are formed side by side in the axial direction on the outer periphery of the non-circular shaft portion 60 (see FIG. 12).

The rotation stopper surface 62 is a surface that directly contacts and receives the inner circumference of the non-circular hole portion 61 when the motor shaft 16 rotates relative to the inner ring 20 . The rotation stopper surface 62 is formed on both sides of the non-circular shaft portion 60 , namely, one side in the circumferential direction and the other side in the circumferential direction. That is, when the motor shaft 16 rotates in one direction in the circumferential direction relative to the inner ring 20, the rotation stopper surface 62 on the one side in the circumferential direction directly contacts the inner circumference of the non-circular hole portion 61 and receives it. When the motor shaft 16 rotates in the other circumferential direction relative to the inner ring 20, the rotation stopper surface 62 on the other circumferential side is in direct contact with the inner circumference of the non-circular hole portion 61 to receive it. .

The elastic member holding portion 63 is a portion that holds the elastic member 64 . The elastic member 64 is a leaf spring in this embodiment. The elastic member 64 is a first plate sandwiched in the circumferential direction between a surface 65a of the elastic member holding portion 63 facing one direction in the circumferential direction and an inner surface 66a of the non-circular hole portion 61 facing the surface 65a in the circumferential direction. A second plate sandwiched in the circumferential direction between the spring portion 67a, the surface 65b of the elastic member holding portion 63 facing the other in the circumferential direction, and the inner surface 66b of the non-circular hole portion 61 facing the surface 65b in the circumferential direction. and a spring portion 67b. The elastic member 64 urges the non-circular shaft portion 60 in one circumferential direction with the second leaf spring portion 67b, and urges the non-circular shaft portion 60 in the other circumferential direction with the first leaf spring portion 67a. The motor shaft 16 is elastically held by the balance of both biasing forces.

As shown in FIG. 11 , the elastic member holding portion 63 holds the elastic member 64 when the motor shaft 16 rotates relative to the inner ring 20 to a position where the rotation stopper surface 62 is received by the inner circumference of the non-circular hole portion 61 . are formed to have surfaces 65a and 65b at positions recessed in the circumferential direction from the rotation stopper surface 62 so that the rotation stopper surface 62 is not permanently deformed due to excessive compression.

Here, the non-circular shaft portion 60 and the non-circular hole portion 61 are set within a predetermined angle range of the motor shaft 16 with respect to the inner ring 20 (5° or more and 15° or less in both forward and reverse directions from the central position of the angle range). A predetermined angular range of play is provided so as to allow relative rotation within a predetermined angle (angle range up to about 10° in the figure) and prevent relative rotation of the motor shaft 16 with respect to the inner ring 20 beyond the predetermined angular range. The inner ring 20 and the motor shaft 16 are connected with each other. Also, as shown in FIG. 11, the elastic member 64 (the first leaf spring portion 67a and the second leaf spring portion 67b) is relatively stable from the state where the inner ring 20 and the motor shaft 16 are at the central position of the predetermined angular range. It is elastically deformed when it rotates, and its elastic restoring force urges the inner ring 20 and the motor shaft 16 toward the center position (position in FIG. 10) of the predetermined angle range.

In the vehicle steering system of the fourth embodiment, when the direction of the steered wheels 3 (see FIG. 1) reaches the stroke end, the driver senses the situation through the steering wheel 1 and suddenly turns the steering wheel 1 in the opposite direction. It is possible to prevent a situation in which the steering wheel 1 is locked and does not move when attempting to rotate in the direction in which the steered wheels 3 return from the stroke end.

That is, when the direction of the steered wheels 3 shown in FIG. 1 reaches the end of the stroke, if the steering lock release state is switched to the steering lock state, the steering wheel 1 cannot be rotated any further, and the driver cannot turn the steering wheel 1 any further. Through the steering wheel 1, it is sensed that the direction of the steered wheels 3 has reached the stroke end. Here, when the driver suddenly tries to turn the steering wheel 1 in the opposite direction, the electromagnet 27 is immediately switched between energization and non-energization in order to allow the rotation of the steering wheel 1, and the steering is locked. At this time, if the motor shaft 16 shown in FIG. The driver may not be able to turn the steering wheel 1 in the opposite direction because the operation to switch to the steering unlocked state is delayed. To address this problem, in the fourth embodiment, the motor shaft 16 is connected to the inner ring 20 with play so as to allow relative rotation with respect to the inner ring 20 within a predetermined angular range. When the rotation of the wheel 1 in one of the forward and reverse directions is blocked, the steering wheel 1 moves in the other of the forward and reverse directions, corresponding to the play provided between the motor shaft 16 and the inner ring 20. It is possible to rotate by the amount of the angle. Therefore, when the driver senses through the steering wheel 1 that the direction of the steered wheels 3 has reached the stroke end and suddenly tries to rotate the steering wheel 1 in the opposite direction, the rotation of the steering wheel 1 is allowed. Therefore, it is possible to secure time for switching from the steering lock state to the steering lock release state, and prevent the steering wheel 1 from being locked and not moving.

FIG. 13 shows a fifth embodiment of the invention. 5th Embodiment differs only in the structure of the elastic member 64 compared with 4th Embodiment, and other structures are the same. Therefore, portions corresponding to those in the fourth embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

The elastic member 64 is a compression coil spring in this embodiment. The elastic member 64 is accommodated in a spring accommodation hole 68 a formed in the non-circular shaft portion 60 so as to open in one direction in the circumferential direction, and the portion protruding from the spring accommodation hole 68 a is supported by the inner surface of the non-circular hole portion 61 . and a spring housing hole 68b formed in the non-circular shaft portion 60 so as to open toward the other side in the circumferential direction. and a second coil spring 69b supported on the inner surface of 61. Both the first coil spring 69a and the second coil spring 69b are compressed in the circumferential direction between the non-circular shaft portion 60 and the non-circular hole portion 61 . The first coil spring 69a and the second coil spring 69b are elastically deformed when the inner ring 20 and the motor shaft 16 rotate relative to each other from the central position of the predetermined angular range. 20 and motor shaft 16 are biased toward the center position of the predetermined angular range.

The vehicle steering system of the fifth embodiment has the same effects as those of the fourth embodiment.

14 and 15 show a sixth embodiment of the invention. 6th Embodiment differs in the structure of the elastic member 64 compared with 4th Embodiment, and other structures are fundamentally the same. Therefore, portions corresponding to those in the fourth embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIG. 14 , the electromagnetic clutch unit 7 includes an intermediate shaft 70 connected to the motor shaft 16 , an inner ring 20 connected to the motor shaft 16 via the intermediate shaft 70 , and fixed to the motor case 15 . a plurality of cam surfaces 22 formed on the outer circumference of the inner ring 20; a cylindrical surface 23 formed on the inner circumference of the outer ring 21; The assembled engaging elements 24, the engaging element retainer 25 that holds the engaging elements 24, the armature 26 that is supported so as to be axially movable, and the electromagnet that attracts the armature 26 by energization and moves it in the axial direction. 27 and a motion converting mechanism 28 for moving the engaging element retainer 25 in the circumferential direction according to the movement of the armature 26 .

The intermediate shaft 70 is splined onto the motor shaft 16 . This spline fit connects the intermediate shaft 70 to the motor shaft 16 without play so that it does not rotate relative to the motor shaft 16 at all.

As shown in FIG. 15, intermediate shaft 70 has a non-circular shaft portion 60 with a non-circular cross-section. The inner ring 20 is formed with a non-circular hole portion 61 into which the non-circular shaft portion 60 of the intermediate shaft 70 is fitted with a gap in the circumferential direction. A rotation stopper surface 62 is formed on the outer circumference of the non-circular shaft portion 60 .

The rotation stopper surface 62 is a surface that directly contacts and receives the inner circumference of the non-circular hole portion 61 when the intermediate shaft 70 rotates relative to the inner ring 20 . The rotation stopper surface 62 is formed on both sides of the non-circular shaft portion 60 , namely, one side in the circumferential direction and the other side in the circumferential direction.

The non-circular shaft portion 60 and the non-circular hole portion 61 allow relative rotation of the intermediate shaft 70 with respect to the inner ring 20 within a predetermined angular range, and prevent relative rotation of the intermediate shaft 70 with respect to the inner ring 20 beyond a predetermined angular range. The inner ring 20 and the intermediate shaft 70 are connected with play in a predetermined angular range.

As shown in FIG. 14, the elastic member 64 is a torsion bar in this embodiment. One end of the elastic member 64 is spline-fitted into a fitting hole 71 formed in the center of the intermediate shaft 70 to prevent rotation, and the other end is also spline-fitted into a fitting hole 72 formed in the inner ring 20 to rotate. being stopped. The elastic member 64 biases the inner ring 20 and the intermediate shaft 70 toward the central position of the predetermined angular range when the inner ring 20 and the intermediate shaft 70 rotate relative to each other from the central position of the predetermined angular range. .

The vehicle steering system of the sixth embodiment has the same effects as those of the fourth embodiment.

16 to 22 show a seventh embodiment of the invention. 7th Embodiment differs in the structure of the motion conversion mechanism 28 compared with 1st Embodiment. That is, in the first embodiment, as the motion conversion mechanism 28, when the electromagnet 27 is energized, the engaging element retainer 25 is circumferentially moved from the disengaged position to the engaging position, and when the electromagnet 27 is not energized, the engaging element retainer 25 is moved. is moved from the engaged position to the disengaged position in the circumferential direction (that is, the electromagnetic clutch unit 7 is an electromagnetic clutch unit 7 that engages when energized). In the embodiment, the motion conversion mechanism 28 moves the engaging element retainer 25 from the engaging position to the disengaging position in the circumferential direction when the electromagnet 27 is energized, and moves the engaging element retainer 25 to the disengaging position when the electromagnet 27 is not energized. The difference is that the electromagnetic clutch unit 7 is a non-excitation actuated clutch that engages when deenergized. Hereinafter, portions corresponding to those in the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIG. 16, the electromagnetic clutch unit 7 includes an inner ring 20 connected to the motor shaft 16, an outer ring 21 fixed so as not to rotate, and an outer ring 21 formed around the inner ring 20. A plurality of cam surfaces 22, a cylindrical surface 23 formed on the inner circumference of the outer ring 21, a plurality of engaging elements 24a, 24b incorporated between the cylindrical surface 23 and the cam surface 22, and the engaging elements 24a, 24b. an armature 26 supported so as to be axially movable; an electromagnet 27 that attracts the armature 26 by energization and moves it in the axial direction; and a motion conversion mechanism 28 for moving the retainer 25 in the circumferential direction.

The inner ring 20 is spline-fitted to the outer circumference of the motor shaft 16 , and the motor shaft 16 is connected to the inner ring 20 by this spline-fitting. As in the fourth to sixth embodiments, the inner ring 20 and the motor shaft 16 are connected with play within a predetermined angular range, and the elastic member 64 is provided between the inner ring 20 and the motor shaft 16. may

The outer ring 21 is formed separately from the clutch case 29 . The clutch case 29 is made of a non-magnetic material (aluminum alloy, copper alloy, etc.). On the other hand, the outer ring 21 is made of steel. As shown in FIG. 17, the outer ring 21 is formed by fitting a common key member 55 into a key groove 53 formed on the inner circumference of the clutch case 29 and a key groove 54 formed on the outer circumference of the outer ring 21. The case 29 prevents rotation.

As shown in FIG. 17, a plurality of cam surfaces 22 are provided on the outer periphery of the inner ring 20 at regular intervals in the circumferential direction. The cam surface 22 is composed of a front cam surface 22a and a rear cam surface 22b arranged behind the front cam surface 22a in the forward rotation direction of the inner ring 20. As shown in FIG. The inner circumference of the outer ring 21 is provided with a cylindrical surface 23 radially facing the front cam surface 22a and the rear cam surface 22b.

Between the cam surface 22 and the cylindrical surface 23, a pair of engaging elements 24a and 24b are incorporated that face each other in the circumferential direction with an engaging element separating spring 73 interposed therebetween. Of the pair of engaging elements 24a and 24b, the front engaging element 24a in the forward rotation direction is incorporated between the front cam surface 22a and the cylindrical surface 23, and the rear engaging element 24b in the forward rotating direction is incorporated in the rear cam surface 22b. It is installed between the cylindrical surfaces 23. The engaging element separating spring 73 presses the engaging elements 24a, 24b in a direction to widen the distance between the pair of engaging elements 24a, 24b.

The front cam surface 22a is formed such that the radial distance from the cylindrical surface 23 gradually decreases from the position of the engaging element 24a toward the front in the normal rotation direction. The rear cam surface 22b is formed so that the radial distance from the cylindrical surface 23 gradually decreases from the position of the engaging element 24b toward the rear in the normal rotation direction.

As shown in FIGS. 16 and 17, the engaging element retainer 25 is a first engaging element supporting one of a pair of engaging elements 24a and 24b facing each other in the circumferential direction with an engaging element separating spring 73 therebetween. and a second split retainer 25b that supports the other engaging element 24b. The first split retainer 25a and the second split retainer 25b are supported so as to be relatively rotatable. , 24b individually.

The first split retainer 25a has a plurality of pillars 74a arranged at intervals in the circumferential direction, and an annular flange 75a connecting the ends of the pillars 74a. Similarly, the second split retainer 25b also has a plurality of pillars 74b arranged at intervals in the circumferential direction, and an annular flange 75b connecting the ends of the pillars 74b.

A column portion 74a of the first split retainer 25a and a column portion 74b of the second split retainer 25b are configured to circumferentially face a pair of engaging elements 24a and 24b with an engaging element separating spring 73 therebetween. It is inserted between the inner periphery of the outer ring 21 and the outer periphery of the inner ring 20 so as to be sandwiched from both sides.

The inner periphery of the flange portion 75a of the first split retainer 25a and the inner periphery of the flange portion 75b of the second split retainer 25b are rotatably supported by the outer periphery of the inner ring 20, respectively. As a result, the first split retainer 25a and the second split retainer 25b widen the distance between the pair of engagers 24a and 24b, so that the engagers 24a and 24b are arranged between the cam surface 22 and the cylindrical surface 23. and an engagement release position for releasing the engagement of the engaging elements 24a and 24b between the cam surface 22 and the cylindrical surface 23 by narrowing the distance between the pair of engaging elements 24a and 24b. It is possible to move in the circumferential direction between.

As shown in FIG. 18, a spring holder 76 is fixed to the side surface of the inner ring 20 . The spring holder 76 has a stopper piece 77 positioned between both pillars 74a and 74b facing each other in the circumferential direction with the pair of engaging elements 24a and 24b interposed therebetween. The stopper piece 77 receives the pillars 74a and 74b when the pillars 74a and 74b move in the direction of narrowing the distance between the pair of engaging elements 24a and 24b.

As shown in FIG. 19, the spring holder 76 has a spring holding piece 78 that holds the engagement member separating spring 73 . The spring holding piece 78 is integrally formed with the stopper piece 77 so as to extend axially between the inner circumference of the outer ring 21 and the outer circumference of the inner ring 20 .

A rotor 79 is provided between the electromagnet 27 and the armature 26, as shown in FIG. A rotor 79 is fixed to the outer circumference of the inner ring 20 . The rotor 79 is made of a magnetic material (iron, silicon steel, etc.).

The armature 26 has a cylindrical portion 80 that is fitted to the outer periphery of the second split retainer 25b with interference. is connected to the second split retainer 25b so as to move integrally with the second split retainer 25b.

As shown in FIGS. 20 to 22, the motion conversion mechanism 28 includes inclined grooves 81a provided on the surface of the flange portion 75a of the first split retainer 25a facing the flange portion 75b of the second split retainer 25b. , the inclined grooves 81b provided in the facing surface of the flange portion 75b of the second split retainer 25b to the flange portion 75a of the first split retainer 25a, and the balls incorporated between the inclined grooves 81a and 81b. 82. The inclined grooves 81a and the inclined grooves 81b are each formed to extend in the circumferential direction. The inclined groove 81a has a groove bottom that is inclined so that it gradually becomes shallower in one direction in the circumferential direction from the deepest portion 83a, which is the deepest in the axial direction. It has a shape with a groove bottom that is inclined so that it gradually becomes shallower from the deepest portion 83b in the other circumferential direction.

In this motion conversion mechanism 28, the armature 26 is attracted to the electromagnet 27, and the flange portion 75b of the second split retainer 25b together with the armature 26 is axially moved toward the flange portion 75a of the first split retainer 25a. When the ball 82 moves in the direction, the ball 82 rolls toward the deepest portions 83a, 83b of the inclined grooves 81a, 81b, so that the pillars 74a, 74b move in the direction of narrowing the distance between the pair of engaging elements 24a, 24b. The first split retainer 25a and the second split retainer 25b are relatively rotated, and the relative rotation moves the engaging element retainer 25 from the engaged position to the disengaged position.

The armature 26 is biased away from the rotor 79 by the force of the engagement member separating spring 73 . That is, the force of the engaging element separating spring 73 shown in FIG. is transmitted to the device 25b. Circumferential force applied to the first split retainer 25a and the second split retainer 25b is converted into an axial force in a direction away from the rotor 79 by the motion conversion mechanism 28 shown in FIGS. and transmitted to the second split retainer 25b. Here, as shown in FIG. 16, the armature 26 is fixed to the second split retainer 25b. is in a state of being urged in the direction away from the rotor 79.

The electromagnetic clutch unit 7 is in a locked state in which rotation of the inner ring 20 is prevented when the electromagnet 27 shown in FIG. 16 is not energized. That is, when the electromagnet 27 is not energized, the armature 26 is axially moved away from the rotor 79 by the force of the engaging member separating spring 73 . At this time, the force of the engaging element separating spring 73 causes the engaging element retainer 25 to move from the disengaged position to the engaged position in the circumferential direction, and the engaging element 24 a on the front side in the normal rotation direction moves forward on the outer circumference of the inner ring 20 . An engaging element 24b engaged between the cam surface 22a and the cylindrical surface 23 on the inner circumference of the outer ring 21 and on the rear side in the normal rotation direction is connected to the rear cam surface 22b on the outer circumference of the inner ring 20 and the inner circumference of the outer ring 21. is engaged with the cylindrical surface 23 of the . Therefore, the rotation of the inner ring 20 is prevented, and the rotation of the motor shaft 16 connected to the inner ring 20 is also prevented.

On the other hand, when the electromagnet 27 is energized, the inner ring 20 is in an idling state in which it can freely rotate with respect to the outer ring 21 . That is, when the electromagnet 27 is energized, the armature 26 is attracted to the rotor 79, and in conjunction with the movement of the armature 26, the flange portion 75b of the second split retainer 25b moves to the flange portion of the first split retainer 25a. 75a axially. At this time, the balls 82 of the motion converting mechanism 28 roll toward the deepest portions 83a and 83b of the respective inclined grooves 81a and 81b, thereby circumferentially moving the engaging element retainer 25 from the engaged position to the disengaged position. While the engagement of the front engaging element 24a in the forward rotation direction between the front cam surface 22a and the cylindrical surface 23 is released, the rear side in the forward rotation direction between the rear cam surface 22b and the cylindrical surface 23 is released. The engagement of the engaging piece 24b is released, and the inner ring 20 and the motor shaft 16 can freely rotate in both forward and reverse directions.

In the vehicle steering system of the seventh embodiment, similarly to the first embodiment, when the direction of the steered wheels 3 reaches the stroke end, the steering wheel 1 is shifted by switching between energization and non-energization of the electromagnet 27. Further rotation is surely prevented, and the driver can surely sense through the steering wheel 1 that the direction of the steered wheels 3 has reached the stroke end.

In the vehicle steering system of the seventh embodiment, when the electromagnet 27 is energized, the steering locked state is switched to the steering unlocked state, and when the electromagnet 27 is deenergized, the steering lock released state is switched to the steering locked state. switch to Therefore, when the power source of the vehicle is turned off and the electromagnet 27 is not energized, such as when the vehicle is parked, the steering wheel 1 is prevented from rotating. It is possible to add a steering wheel lock function to prevent the vehicle from being stolen.

In the seventh embodiment, the outer ring 21 is formed separately from the clutch case 29, and the outer ring 21 is fixed to the clutch case 29. However, as shown in FIG. may be integrally formed with

24 to 27 show an eighth embodiment of the invention. The eighth embodiment differs from the second embodiment only in the configuration for fixing the outer ring 21 and the electromagnet 27 in the axial direction, and the rest of the configuration is basically the same. Therefore, portions corresponding to those in the second embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIG. 24, the electromagnet 27 is arranged inside the clutch case 29 so as to face the outer ring 21 in the axial direction. The clutch case 29 has a cylindrical portion 29a fitted to the outer circumference of the field core 35 of the electromagnet 27, and an end plate portion 29b supporting the axial end face of the field core 35 of the electromagnet 27. As shown in FIG. The end plate portion 29b constitutes an electromagnet movement restricting portion that restricts movement of the electromagnet 27 in one axial direction (downward in the drawing). A retaining ring 52 mounted on the inner periphery of the open end of the cylindrical portion 29a constitutes an outer ring movement restricting portion that restricts the movement range of the outer ring 21 in the other axial direction (upward in the drawing).

The end plate portion 29b is formed integrally with the cylindrical portion 29a. A detent hole 85 into which a detent projection 84 formed on the axial end face of the field core 35 is inserted is formed in the end plate portion 29b. The electromagnet 27 is circumferentially positioned with respect to the clutch case 29 by the engagement between the anti-rotation projection 84 and the anti-rotation hole 85 . A rolling bearing 86 that rotatably supports the inner ring 20 is mounted on the end plate portion 29b.

An annular elastic spacer 87 is incorporated between the outer ring 21 and the electromagnet 27 . The elastic spacer 87 is assembled in an axially compressed state, and its elastic restoring force urges the outer ring 21 and the electromagnet 27 away from each other in the axial direction. One axial end of the elastic spacer 87 presses the surface of the outer ring 21 axially facing the field core 35 , and the other axial end of the elastic spacer 87 presses the axially facing surface of the field core 35 facing the outer ring 21 . are pressing. The elastic spacer 87 is made of a non-magnetic material (aluminum alloy, copper alloy, etc.).

A disc spring 87a can be used as the elastic spacer 87, as shown in FIG. The disc spring 87a is a conical cylindrical metal spring. A single disc spring 87a can be used as the elastic spacer 87, but as shown in the figure, a plurality of disc springs 87a arranged in the axial direction with the directions of the large diameter side and the small diameter side alternated are used as the elastic spacer. With 87, the axial length of the elastic spacer 87 can be ensured. When the disc spring 87a is used as the elastic spacer 87, the disc spring 87a can generate a large force in a narrow installation space, so that the axial movement of the outer ring 21 and the electromagnet 27 can be reliably restricted.

A wave spring 87b can also be used as the elastic spacer 87, as shown in FIG. The wave spring 87b is an annular metal spring that is formed so that waveforms are repeated along the circumferential direction. Although it is possible to use a single wave spring 87b as the elastic spacer 87, as shown in the figure, the elastic spacer 87 consists of a wave spring 87b and an annular flat washer 87c alternately arranged in the axial direction. Then, the axial length of the elastic spacer 87 can be ensured.

As shown in FIG. 27, it is also possible to use a compression coil spring 87d as the elastic spacer 87. FIG. The compression coil spring 87d is a spring formed by spirally winding a metal wire. If the compression coil spring 87d is used as the elastic spacer 87, the elastic spacer 87 can be arranged in a space with a small radial width.

The vehicle steering system of the eighth embodiment can keep the machining cost of the clutch case shown in FIG. 24 low. That is, when the outer ring 21 and the electromagnet 27 are arranged in the clutch case 29 so as to face each other in the axial direction, in order to fix the outer ring 21 and the electromagnet 27 in the axial direction, the axial movement of the electromagnet 27 in the direction toward the outer ring 21 is required. and a retaining ring (not shown) for restricting the axial movement of the outer ring 21 in the direction toward the electromagnet 27, respectively. It is conceivable to employ a configuration in which the grooves are formed on the inner periphery, but this configuration requires the cost of forming grooves on the inner periphery of the clutch case 29 . On the other hand, as in the eighth embodiment, an elastic spacer 87 is incorporated between the outer ring 21 and the electromagnet 27 to bias the two axially away from each other. and the axial movement of the outer ring 21 in the direction approaching the electromagnet 27, grooves for attaching a snap ring to the inner circumference of the clutch case 29 are required. Since there is no need to do so, the machining cost of the clutch case 29 can be kept low.

Further, in the vehicle steering system of the eighth embodiment, the elastic spacer 87 shown in FIG. 24 is made of a non-magnetic material. It can be prevented from leaking through and the armature 26 can be effectively sucked. Therefore, the sizes of the electromagnet 27 and the armature 26 can be kept small, and space can be saved.

FIG. 28 shows a ninth embodiment of the invention. In each of the above-described embodiments, as shown in FIG. 1 or FIG. 7, the steering apparatus for a vehicle that steers a pair of left and right steered wheels 3 of a vehicle has been described as an example. , a rudder (outboard motor, etc.) at the stern of a ship (not shown) as a steering target.

In the ninth embodiment, as compared with the eighth embodiment, the inner ring 20 is indirectly connected to the steering shaft 4 (see FIG. 1) via the motor shaft 16 of the reaction motor 6 in the eighth embodiment. In contrast, the ninth embodiment differs in that the reaction force motor 6 is not provided and the inner ring 20 is directly connected to the steering shaft 4, but the rest of the configuration is basically the same. be. Therefore, portions corresponding to those of the eighth embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

The steering shaft 4 is inserted into a steering insertion hole 89 formed in a dashboard panel 88 of the ship. The end of the steering shaft 4 on the side of insertion into the steering insertion hole 89 is spline-fitted to the inner ring 20 . A radially outwardly extending flange portion 30 is formed at one axial end of the clutch case 29, and the flange portion 30 is fixed to a dashboard panel 88 of the ship with bolts (not shown). The clutch case 29 is fixed to the dashboard panel 88 so as not to rotate even when the steering wheel 1 (see FIG. 1) is steered.

In the marine steering apparatus of the ninth embodiment, similarly to the above-described embodiments, when the direction of the rudder (outboard motor or the like) at the stern of the marine vessel (not shown) reaches the stroke end, the electromagnet 27 is energized and de-energized. , the steering wheel 1 is reliably prevented from rotating further, and the driver is informed through the steering wheel 1 that the direction of the rudder (outboard motor, etc.) at the stern of the ship (not shown) has reached the stroke end. You can definitely feel what you are doing.

29 and 30 show a tenth embodiment of the invention. The tenth embodiment corresponds to the seventh embodiment in which the relationship between the inner ring 20 and the outer ring 21 with respect to the motor shaft 16 and the clutch case 29 is reversed. Specifically, in the tenth embodiment, in comparison with the seventh embodiment, of the inner ring 20 and the outer ring 21, the inner ring 20 is connected to the motor shaft 16 and the outer ring 21 is connected to the clutch case 29. In contrast to the inner ring 20 and the outer ring 21, the tenth embodiment is different in that the outer ring 21 is connected to the motor shaft 16 and the inner ring 20 is connected to the clutch case 29, but the rest of the configuration is basically the same. are essentially identical. Therefore, portions corresponding to those in the seventh embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIG. 29, the electromagnetic clutch unit 7 includes an outer ring 21 connected to the motor shaft 16, an outer ring 21 connected to a clutch case 29, and an inner ring 20. A plurality of cam surfaces 22, a cylindrical surface 23 formed on the inner circumference of the outer ring 21, a plurality of engaging elements 24a, 24b incorporated between the cylindrical surface 23 and the cam surface 22, and the engaging elements 24a, 24b. an armature 26 supported so as to be axially movable; an electromagnet 27 that attracts the armature 26 by energization and moves it in the axial direction; and a motion conversion mechanism 28 for moving the retainer 25 in the circumferential direction.

The outer ring 21 has an outer ring end plate 21a axially facing the shaft end of the inner ring 20, and an outer ring shaft portion 21b axially extending from the outer ring end plate 21a. The outer ring shaft portion 21b is spline-fitted with the motor shaft 16 . The outer ring 21 is connected to the motor shaft 16 by this spline fitting.

The clutch case 29 has a cylindrical portion 29a fitted to the outer circumference of the field core 35 of the electromagnet 27, and an end plate portion 29b supporting the axial end face of the field core 35 of the electromagnet 27. As shown in FIG. The end plate portion 29b is formed integrally with the cylindrical portion 29a. A detent hole 85 into which a detent projection 84 formed on the axial end face of the field core 35 is inserted is formed in the end plate portion 29b. The electromagnet 27 is circumferentially positioned with respect to the clutch case 29 by the engagement between the anti-rotation projection 84 and the anti-rotation hole 85 .

The inner ring 20 is connected to the clutch case 29 by an inner ring connecting shaft 29c provided on an end plate portion 29b of the clutch case 29, which prevents rotation. The inner ring 20 and the inner ring connecting shaft 29c can be connected without play so as not to rotate relative to each other like the inner ring 20 and the motor shaft 16 shown in FIG. Like the motor shaft 16, the inner ring 20 is allowed to rotate relative to the inner ring connecting shaft 29c within a predetermined angular range, and the relative rotation of the inner ring 20 to the inner ring connecting shaft 29c exceeding the predetermined angular range is prevented. A state in which the inner ring 20 and the inner ring connecting shaft 29c are connected with play within a predetermined angular range, and the inner ring 20 and the inner ring connecting shaft 29c are positioned between the inner ring 20 and the inner ring connecting shaft 29c at the central position of the predetermined angular range. An elastic member 64 (see FIG. 9) is provided to urge the inner ring 20 and the inner ring connecting shaft 29c toward the central position of a predetermined angular range when they are rotated relative to each other.

As shown in FIG. 29, no rotor 79 (see FIG. 16) is provided between the electromagnet 27 and the armature 26, and the armature 26 is arranged to face the electromagnet 27 directly.

The armature 26 is urged away from the electromagnet 27 by the force of the engagement member separating spring 73 (see FIG. 30). That is, the force of the engaging element separating spring 73 shown in FIG. is transmitted to the device 25b. Circumferential force applied to the first split retainer 25a and the second split retainer 25b is converted by the motion converting mechanism 28 into an axial force in a direction away from the electromagnet 27, thereby performing the second split holding. is transmitted to the device 25b. Here, since the second split retainer 25b is fixed to the armature 26, after all, the armature 26 is moved by the force transmitted from the engagement member separating spring 73 (see FIG. 30) through the motion conversion mechanism 28. It is in a state of being energized in a direction away from the electromagnet 27 .

When the electromagnet 27 shown in FIG. 29 is not energized, the electromagnetic clutch unit 7 is in a locked state in which the outer ring 21 is prevented from rotating. That is, when the electromagnet 27 is de-energized, the armature 26 is axially moved away from the electromagnet 27 by the force of the engagement member separating spring 73 (see FIG. 30). At this time, the force of the engaging element separating spring 73 causes the engaging element retainer 25 to move from the disengaged position to the engaged position in the circumferential direction, and the engaging element 24 a on the front side in the normal rotation direction moves forward on the outer circumference of the inner ring 20 . An engaging element 24b engaged between the cam surface 22a and the cylindrical surface 23 on the inner circumference of the outer ring 21 and on the rear side in the normal rotation direction is connected to the rear cam surface 22b on the outer circumference of the inner ring 20 and the inner circumference of the outer ring 21. is engaged with the cylindrical surface 23 of the . Therefore, the rotation of the outer ring 21 is blocked, and the rotation of the motor shaft 16 connected to the outer ring 21 is also blocked.

On the other hand, when the electromagnet 27 is energized, the outer ring 21 is in an idling state in which it can freely rotate with respect to the inner ring 20 . That is, when the electromagnet 27 is energized, the armature 26 is attracted to the electromagnet 27, and in conjunction with the movement of the armature 26, the flange portion 75b of the second split retainer 25b moves to the flange portion of the first split retainer 25a. 75a axially. At this time, the relative axial movement of the first split retainer 25a and the second split retainer 25b is changed by the motion converting mechanism 28 into the relative movement of the first split retainer 25a and the second split retainer 25b. , the front side engaging element 24a in the forward rotation direction is disengaged from the front cam surface 22a and the cylindrical surface 23, and the rear cam surface 22b and the cylindrical surface 23 move. The engagement of the engaging element 24b on the rear side in the forward rotation direction is released, and the outer ring 21 and the motor shaft 16 can freely rotate in both forward and reverse directions.

In the vehicle steering system of the tenth embodiment, similarly to the seventh embodiment, when the electromagnet 27 is energized, the steering locked state is switched to the steering unlocked state. The unlocked state is switched to the steering lock state. Therefore, when the power source of the vehicle is turned off and the electromagnet 27 is not energized, such as when the vehicle is parked, the steering wheel 1 is prevented from rotating. It is possible to add a steering wheel lock function to prevent the vehicle from being stolen. Other functions and effects are the same as those of the seventh embodiment.

FIG. 31 shows an eleventh embodiment of the invention. In the eleventh embodiment, as compared with the tenth embodiment, the clutch case 29 is formed separately from the motor case 15 of the reaction motor 6, and the clutch case 29 is attached to the motor case 15. In the eleventh embodiment, the only difference is that the clutch case 29 is formed integrally with the motor case 15 of the reaction motor 6, and the rest of the configuration is the same. Therefore, the same reference numerals are given to the parts corresponding to the tenth embodiment, and the description thereof is omitted.

In each of the above-described embodiments, rollers are used as the engaging elements 24, 24a, and 24b to be incorporated between the inner circumference of the outer ring 21 and the outer circumference of the inner ring 20. However, balls or sprags may be used as the engaging elements. It is also possible to use

In the first to eleventh embodiments (excluding the ninth embodiment), a vehicle steering apparatus for steering a pair of left and right steerable wheels 3 of a vehicle is provided as an example of the steer-by-wire type steering apparatus according to the present invention. In the ninth embodiment, as an example of the steer-by-wire steering system according to the present invention, a steer-by-wire system for steering a rudder (such as an outboard motor) provided at the stern of a ship is described. However, the present invention is applicable not only to vehicle steering systems and marine vessel steering systems, but also to construction machinery, agricultural machinery, and all-terrain vehicles as long as the steering system is of the steer-by-wire system. , multi-purpose four-wheeled vehicles, etc., can be similarly applied.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

1 steering wheel 2 steering actuator 3 steered wheel (steering target)
4 Steering shaft 5 Steering sensor 6 Reaction motor 16 Motor shaft 20 Inner ring 21 Outer rings 24, 24a, 24b Engagement element 25 Engagement element retainer 26 Armature 27 Electromagnet 28 Operation conversion mechanism 29 Clutch case (fixing member)
29b end plate portion (electromagnet movement restricting portion)
52 Retaining ring (outer ring movement restricting portion)
60 Non-circular shaft portion 61 Non-circular hole portion 64 Elastic member 70 Intermediate shaft 87 Elastic spacer 87a Disc spring 87b Wave spring 87d Compression coil spring

Claims (16)

a steering wheel (1);
a steering sensor (5) for detecting the amount of operation of the steering wheel (1);
The steering wheel (1) is mechanically separated from the steering wheel (1), and the steering wheel (1) changes the direction of the steered object (3) according to the amount of operation of the steering wheel (1) detected by the steering sensor (5). A steer-by-wire steering system comprising a rudder actuator (2),
a shaft (4, 16, 70) connected to the steering wheel (1) so as to rotate together with the steering wheel (1);
a fixed member (29) fixedly provided against rotation;
an inner ring (20) connected to one of the shaft (4, 16, 70) and the fixed member (29);
an outer ring (21) connected to the other of the shaft (4, 16, 70) and the fixed member (29);
engaging elements (24, 24a, 24b) incorporated between the outer circumference of the inner ring (20) and the inner circumference of the outer ring (21);
an engaging position for holding the engaging elements (24, 24a, 24b) and engaging the engaging elements (24, 24a, 24b) between the inner ring (20) and the outer ring (21); 20) and an engaging element retainer ( 25) and
an armature (26) supported for axial movement;
an electromagnet (27) that attracts and moves the armature (26) in the axial direction when energized;
a motion converting mechanism (28) for circumferentially moving the engaging element retainer (25) from one of the engaging position and the disengaging position to the other in accordance with the movement of the armature (26). A steer-by-wire steering system characterized by: The inner ring (20) is connected to the shaft (4, 16, 70),
The steer-by-wire steering system according to claim 1, wherein the outer ring (21) is connected to the fixed member (29). The inner ring (20) and the shafts (4, 16, 70) allow relative rotation of the shafts (4, 16, 70) with respect to the inner ring (20) within a predetermined angular range. ) with play in the predetermined angular range so as to prevent relative rotation of the shaft (4, 16, 70) with respect to the shaft (4, 16, 70) beyond the predetermined angular range,
Between the inner ring (20) and the shaft (4, 16, 70), there is a relative An elastic member (64) is provided that biases the inner ring (20) and the shaft (4, 16, 70) toward the central position of the predetermined angular range when rotated.
The steer-by-wire steering system according to claim 2. said shaft (4, 16, 70) has a non-circular shank (60) with a non-circular cross-section;
The inner ring (20) has a non-circular hole (61) that fits into the non-circular shaft (60) with a circumferential gap,
The elastic member (64) is a leaf spring sandwiched in the circumferential direction between the non-circular shaft (60) and the non-circular hole (61),
The steer-by-wire steering system according to claim 3. said shaft (4, 16, 70) has a non-circular shank (60) with a non-circular cross-section;
The inner ring (20) has a non-circular hole (61) that fits into the non-circular shaft (60) with a circumferential gap,
The elastic member (64) is a compression coil spring that is compressed and incorporated between the non-circular shaft (60) and the non-circular hole (61).
The steer-by-wire steering system according to claim 3. said shaft (4, 16, 70) has a non-circular shank (60) with a non-circular cross-section;
The inner ring (20) has a non-circular hole (61) that fits into the non-circular shaft (60) with a circumferential gap,
One end of the elastic member (64) is fitted into a fitting hole formed in the center of the shaft (4, 16, 70) to prevent rotation, and the other end of the elastic member (64) is prevented from rotating by the inner ring (20). is a torsion bar,
The steer-by-wire steering system according to claim 3. The fixing member (29) is a tubular clutch case that houses the electromagnet (27) and the armature (26),
The outer ring (21) is integrally formed with the clutch case (29),
A steer-by-wire steering system according to any one of claims 2 to 6. The fixing member (29) is a tubular clutch case (29) that houses the electromagnet (27) and the armature (26),
The clutch case (29) is made of a non-magnetic material,
The outer ring (21) is formed separately from the clutch case (29) and is prevented from rotating by the clutch case (29).
A steer-by-wire steering system according to any one of claims 2 to 6. The fixing member (29) is a tubular clutch case (29) that houses the electromagnet (27) and the armature (26),
The outer ring (21) is formed separately from the clutch case (29) and is prevented from rotating by the clutch case (29),
The electromagnet (27) is disposed in the clutch case (29) axially facing the outer ring (21),
The clutch case (29) includes an electromagnet movement restricting portion (29b) for restricting the movement of the electromagnet (27) in one axial direction, and an outer ring movement restricting portion (29b) for restricting the movement range of the outer ring (21) in the other axial direction. A regulation part (52) is provided,
An elastic spacer (87) is incorporated between the outer ring (21) and the electromagnet (27) for urging them in a direction to move them apart in the axial direction.
A steer-by-wire steering system according to any one of claims 2 to 6. The steer-by-wire steering system according to claim 9, wherein the elastic spacer (87) is one of a disk spring (87a), a wave spring (87b), and a compression coil spring (87d). The steer-by-wire steering system according to claim 9 or 10, wherein the elastic spacer (87) is made of a non-magnetic material. The outer ring (21) is connected to the shaft (4, 16, 70),
The steer-by-wire steering system according to claim 1, wherein the inner ring (20) is connected to the fixed member (29). The inner ring (20) and the fixing member (29) allow relative rotation of the inner ring (20) with respect to the fixing member (29) within a predetermined angular range, and the inner ring (20) with respect to the fixing member (29). 20) are connected with play in the predetermined angular range so as to prevent relative rotation exceeding the predetermined angular range;
Between the inner ring (20) and the fixing member (29), there is a gap between the inner ring (20) and the fixing member (29) when the inner ring (20) and the fixing member (29) rotate relative to each other from the central position of the predetermined angular range. (20) and an elastic member (64) that biases the fixing member (29) toward the central position of the predetermined angle range;
The steer-by-wire steering system according to claim 12. The fixing member (29) is a tubular clutch case (29) that houses the electromagnet (27) and the armature (26),
The clutch case (29) is made of a non-magnetic material,
The steer-by-wire steering system according to claim 13. further comprising a reaction force motor (6) that applies a steering reaction force to the steering wheel (1);
The fixing member (29) is a tubular clutch case (29) that houses the electromagnet (27) and the armature (26),
The clutch case (29) is formed integrally with a motor case (15) of the reaction motor (6),
The steer-by-wire steering system according to claim 13. When the electromagnet (27) is energized, the motion converting mechanism (28) circumferentially moves the engaging element retainer (25) from the disengagement position to the engagement position to disengage the electromagnet (27). When energized, the engaging element retainer (25) is configured to move in the circumferential direction from the engaging position to the disengaging position.
A steer-by-wire steering system according to any one of claims 1 to 15.

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