JP6743566B2 - Steer-by-wire steering system - Google Patents

Description

The present invention relates to a steer-by-wire type steering device.

As a related technique, Patent Document 1 discloses a steer-by-wire type steering device. In this steer-by-wire steering device, a motor as an actuator and a ball screw mechanism including a screw shaft and a nut shaft are provided. That is, the linear motion actuator is configured by converting the rotational movement of the screw shaft by the motor into the linear movement of the nut shaft by the ball screw mechanism. The nut shaft that moves linearly is connected to the knuckle arm via the tie rod arm. As a result, steering via the actuator is realized.

JP, 2007-326459, A

However, in the above technique, since the motor and the ball screw mechanism need to be fixed to the vehicle body, a member for fixing is required on the vehicle body side. As a result, the weight and space occupancy of the entire apparatus including peripheral parts increase.

Further, in the above technique, one end of the ball screw mechanism is fixed to the vehicle body, and the load from the tie rod arm is input to the nut shaft that constitutes the other end side. Lateral load will be applied. Therefore, it is necessary to secure the strength and rigidity of the ball screw mechanism, and the screw shaft and the net shaft of the ball screw mechanism have to be designed large.

Therefore, it is an object of the present invention to provide a steer-by-wire type steering device in which a linear motion actuator can be designed to be lightweight and the weight of peripheral components can be easily reduced.

A steer-by-wire steering device according to a first aspect is a suspension arm, a tire hub unit rotatably supported by the suspension arm about a steering rotation axis, and a linear motion that expands and contracts based on an operation of a steering input device. A steer-by-wire type steering device comprising: an actuator, wherein the linear motion actuator is rotatably supported by the tire hub unit and an arm support portion rotatably supported by the suspension arm; And a tire support part whose distance from the arm support part changes due to expansion and contraction of the linear motion actuator.

In the steer-by-wire steering apparatus according to the first aspect, the tire hub unit is supported by the suspension arm. The tire hub unit is rotatable around a steering rotation axis (steering rotation center).

Further, the steer-by-wire steering system according to the first aspect includes a linear motion actuator that expands and contracts based on the operation of the steering input device. The linear motion actuator includes an arm support portion and a tire support portion whose distance from the arm support portion changes due to expansion and contraction of the linear motion actuator. Of these, the arm support portion is rotatably supported by the suspension arm. On the other hand, the tire support portion is rotatably supported by the tire hub unit.
Therefore, as the linear motion actuator expands and contracts based on the operation of the steering input device, the tire hub unit rotates about the steering rotation axis with respect to the suspension arm. That is, the tire hub unit can be steered by operating the steering input device.

Particularly, in the steer-by-wire type steering device according to the first aspect, since the linear motion actuator is rotatably supported by both the arm support portion and the tire support portion, the linear motion actuator has a linear movement direction. Lateral loads other than the load do not work. Therefore, compared to the case where a lateral load acts on the linear motion actuator, it is less necessary to secure the rigidity of the linear motion actuator against the lateral load. Therefore, the linear motion actuator only needs to have rigidity that does not buckle with respect to the load in the linear motion direction, so that the linear motion actuator can be designed to be lightweight.

Further, as described above, the linear motion actuator is supported by both the arm support portion and the tire support portion. Therefore, when mounting the steer-by-wire type steering device on the vehicle body, the suspension arm may be mounted on the vehicle body, and it is not necessary to directly mount the linear motion actuator on the vehicle body. Therefore, the assemblability is high.

A steer-by-wire type steering device according to a second aspect is the steer-by-wire type steering device according to the first aspect, in which the longitudinal direction of the linear actuator is in front of the device and outside in the device width direction regardless of the expansion/contraction state thereof. It is supposed to be diagonal.

In the steer-by-wire steering system according to the second aspect, the longitudinal direction of the linear motion actuator is an oblique direction that is in front of the device and outward in the device width direction regardless of the expansion/contraction state thereof. Therefore, the dimension of the steering device in the width direction can be designed smaller than in the case where the longitudinal direction of the linear motion actuator is provided parallel to the device width direction. Therefore, it is easy to secure a space in the central portion in the width direction of the vehicle when it is attached to the vehicle body.

A steer-by-wire steering system according to a third aspect is the steer-by-wire steering system according to the first or second aspect , wherein the suspension arm includes an opening penetrating in the device width direction, and The actuator is inserted through the opening and is supported by the suspension arm above and below the linear motion actuator.

In the steer-by-wire steering system according to the third aspect , the suspension arm has an opening that penetrates in the device width direction. The linear actuator is inserted through this opening. Then, the linear motion actuator is supported by the suspension arm 20 above and below.
Therefore, it is possible to prevent a moment from being generated in the suspension arm due to the load input from the linear motion actuator. Therefore, while maintaining the rigidity of the suspension arm, the space occupancy rate of the entire steering device can be kept low.

A steer-by-wire type steering device according to a fourth aspect is the steer-by-wire type steering device according to any one of the first to third aspects, wherein the tire support portion of the linear motion actuator is in a straight traveling state from a steering rotation shaft. Is also located in front of the device.

In the steer-by-wire steering system according to the fourth aspect, the tire support portion of the linear actuator is located in front of the steering rotation shaft in the straight traveling state. Therefore, by contracting the linear motion actuator, a large steering angle inward in the device width direction can be realized.

A steer-by-wire type steering device according to a fifth aspect is the steer-by-wire type steering device according to the fourth aspect , wherein a direction in which the tire hub unit faces and a longitudinal direction of the linear motion actuator are in an outer maximum steering state. It is a substantially parallel relationship.

In the steer-by-wire steering system according to the fifth aspect, the direction in which the tire hub unit faces and the longitudinal direction of the linear motion actuator are substantially parallel to each other in the outer maximum steering state. Therefore, it is easy to set the positional relationship between the tire hub unit and the linear actuator so that the distance between the tire hub unit and the linear actuator becomes narrower in the maximum outer steering state. Therefore, the space occupancy of the steer-by-wire steering system can be further suppressed.

A steer-by-wire steering apparatus according to a sixth aspect is the steer-by-wire steering apparatus according to any one of the first to fifth aspects , wherein the steer-by-wire steering apparatus is a shock that connects the suspension arm and the vehicle body. The shock absorber further includes an absorber, and the shock absorber intersects the linear actuator in a plan view.

The steer-by-wire steering system according to the sixth aspect further includes a shock absorber that connects the suspension and the vehicle body. The shock absorber intersects the linear actuator in a plan view. Therefore, when the steering device includes the shock absorber, the space occupancy of the entire steer-by-wire steering device can be efficiently suppressed to be low.

A steer-by-wire type steering device according to a seventh aspect is the steer-by-wire type steering device according to the sixth aspect , wherein the steer-by-wire type steering device further includes an attachment member fixed to a vehicle body. Supports the suspension arm rotatably and also connects the other end of the shock absorber whose one end is connected to the suspension arm.

The steer-by-wire steering apparatus according to the seventh aspect further includes an attachment member fixed to the vehicle body. The suspension arm is rotatably (swingably) supported by the mounting member. Further, the mounting member is connected to the other end of the shock absorber whose one end is connected to the suspension arm. Therefore, by fixing the mounting member to the vehicle body, the steer-by-wire type steering device including the shock absorber can be assembled to the vehicle body. That is, it is not necessary to separately attach the other end of the shock absorber 50 to the vehicle body. Therefore, the assemblability is high.

A steer-by-wire steering apparatus according to an eighth aspect is the steer-by-wire steering apparatus according to any one of the first to seventh aspects , wherein the steer-by-wire steering apparatus is attached to a front portion or a rear portion of a vehicle body. If it is attached to the front part of the vehicle body, it is a leading arm type suspension system, and if it is attached to the rear part of the vehicle body, it is a trailing arm type or semi-trailing arm type suspension system. There is.

In the steer-by-wire type steering device according to the eighth aspect, the steer-by-wire type steering device is attached to the front part or the rear part of the vehicle body, and when it is attached to the front part of the vehicle body, it is a leading arm type suspension system. If it is attached to the rear part of the vehicle body, it is of a trailing arm type or a semi-trailing arm type suspension type. Therefore, it is easy to install the steer-by-wire type steering device near the portion of the vehicle body forming the vehicle interior. Here, in general, the portion forming the vehicle interior is often designed with relatively high rigidity in the entire vehicle body. Therefore, according to the configuration of the eighth aspect, it is easy to attach the steer-by-wire steering device to the vehicle body with high rigidity.

As described above, the steer-by-wire type steering device according to the present invention has an excellent effect that the linear motion actuator can be designed to have a light weight and the weight of peripheral components can be easily reduced.

FIG. 1 is a perspective view showing a steering device according to an embodiment. FIG. 2 is a plan view of the steering device shown in FIG. 1 as seen from above the device. (A) shows a state where the steering is performed outside, (B) shows a straight traveling state, and (C) shows a state where the steering is performed inside. Indicates. FIG. 3 is a perspective view showing a mode in which the steering system shown in FIG. 1 is further provided with a shock absorber and a bracket (note that the tire hub unit is not shown). FIG. 4 is a perspective view showing a mode in which the steering system shown in FIG. 1 is further provided with a shock absorber and a bracket. 5A is a plan view of the steering device shown in FIG. 4 viewed from above the device, and FIG. 5B is a side view of the steering device shown in FIG. 4 viewed from the outside in the device width direction. FIG. 6(A) is a perspective view showing a vehicle body to which the steering device is attached, and FIG. 6(B) is a perspective view showing a state in which the steering device is attached to the vehicle body.

Hereinafter, a steer-by-wire steering apparatus 10 (hereinafter simply referred to as “steering apparatus 10”) according to an embodiment of the present invention will be described with reference to the drawings.

<Schematic configuration of the steering device 10>
As shown in FIG. 1, the steering device 10 is configured to include a tire hub unit 30, a suspension arm 20, and a linear motion actuator 40. Each configuration will be described below.

Note that the arrow UP shown in each drawing is the upper side of the device, the arrow FR is the front of the device, and the arrow OUT is the outer side in the device width direction. In the following description, in the case of simply using the directions of front and rear, top and bottom, and inside and outside in the width direction, unless otherwise specified, front and rear in the device front and rear direction, up and down in the device vertical direction, and inside and outside in the device width direction are indicated.

Further, the steering device 10 operates as shown in FIGS. 2A to 2C according to the extension state of the linear motion actuator 40, but unless otherwise specified, the arrangement in the straight traveling state shown in FIG. 2B. Explain the relationship.

<Tire hub unit 30>
The tire hub unit 30 includes a main body portion 31 and a rolling portion 32 that rotationally drives the main body portion 31 around the axle D. 1 and 2, the upper half of the rolling portion 32 is shown in a cut state.

The main body 31 is configured to include a housing 33 that forms an outer shell thereof and a drive device (not shown) mounted in the housing 33. The housing 33 is rotatably supported by a suspension arm 20 described below at its upper and lower portions (see FIGS. 4 and 5B).

The rolling portion 32 includes a tire 34 and a wheel 35 that supports the tire 34. The rolling portion 32 is configured so as to surround the main body portion 31. Further, the rolling portion 32 is rotationally driven around the axle D with respect to the body portion 31 by the drive device of the body portion 31. That is, the drive device is configured to include a motor, and controls the rotation of the rolling portion 32 with respect to the main body portion 31 according to the operation of an input device (not shown) such as an accelerator pedal. Further, the tire hub unit 30 is provided with a braking device (brake) such as a disc brake, and rotation of the rolling portion 32 with respect to the main body portion 31 or the like is performed in response to an operation of an input device (not shown) such as a brake pedal. It is configured to be controlled. In this way, the tire hub unit 30 is configured as a so-called in-wheel motor.

Further, the main body portion 31 is configured to include a steering rotational force point portion 36 that rotatably supports a linear motion actuator 40 described later. The steering rotational force point portion 36 is provided at a position that protrudes inward in the device width direction from the front end portion in the device front-rear direction of the housing 33. Further, the position of the steering rotational force point portion 36 in the vertical direction of the device is set higher than the central portion of the housing 33 in the vertical direction (a height corresponding to the axle D).

<Suspension arm 20>
The suspension arm 20 is attached to the vehicle body 100 (see FIG. 6) so as to be rotatable (swingable) around the suspension rotation central axis E. Further, the suspension arm 20 supports the main body 31 of the tire hub unit 30 so as to be rotatable about the steering rotation axis C. Further, the suspension arm 20 rotatably supports a linear motion actuator 40 described later. In other words, the suspension arm 20 is configured to include the suspension rotation center portion 21, the tire support portion 25, and the actuator support portion 29. Hereinafter, each of these configurations and configurations related thereto will be described.

(Suspension center 21)
The suspension rotation center portion 21 is a portion rotatably supported by the vehicle body 100 around a suspension rotation center axis E indicated by a chain line in FIG. The suspension rotation center portion 21 has a substantially quadrangular prism shape, and its axial direction is oriented in the device width direction. The protrusions 21A protruding from both ends of the suspension rotation center 21 in the axial direction are connected to a mounting member 60 (see FIG. 3) fixed to the vehicle body 100.

(Tire support 25)
The tire support portion 25 is a portion that rotatably supports the tire hub unit 30. As shown in FIGS. 4 and 5(B), the tire support portion 25 supports the tire hub unit 30 at the upper portion and the lower portion of the body portion 31 thereof. In other words, the tire support portion 25 is composed of an upper support portion 25U that supports the upper portion of the main body portion 31 of the tire hub unit 30, and a lower support portion 25L that supports the lower portion of the main body portion 31 of the tire hub unit 30. ing. Both the upper support portion 25U and the lower support portion 25L are provided with, for example, spherical bearings, the outer ring of the spherical bearings is fixed to the suspension arm 20 side, and the inner ring of the spherical bearings is fixed to the tire hub unit 30 side. Has been done. As a result, the tire hub unit 30 can rotate with respect to the suspension arm 20 about a virtual axis (steering rotation axis C) that connects the upper support portion 25U and the lower support portion 25L of the tire support portion 25. ..

(Upper connecting portion 22)
The suspension rotation center portion 21 and the upper support portion 25U are connected by the upper connection portion 22. Here, as shown in FIG. 5B, the upper support portion 25U is located above the suspension rotation center portion 21 in the positional relationship in the device vertical direction. Therefore, the upper connecting portion 22 that connects the two is extended so as to extend upward from the suspension rotation center portion 21 and then change the direction toward the front of the device. In other words, the upper connecting portion 22 includes a standing portion 22H that stands up from the upper portion of the suspension rotation center portion 21 and an upper wall portion 22W that extends from the upper portion of the standing portion 22H toward the front of the device. I have it. Further, as shown in FIG. 5A, the upper support portion 25U is located outside the suspension rotation center portion 21 in the device width direction in the positional relationship in the device width direction. Therefore, the upper wall portion 22W extends from the upper end of the standing portion 22H once toward the front of the device and then extends outward while changing the direction outward in the device width direction.

(Lower connecting portion 24)
As shown in FIGS. 3 and 5B, the suspension rotation center portion 21 and the lower support portion 25L are connected by the lower connection portion 24. Here, as shown in FIG. 5(B), the lower support portion 25L is located slightly below the suspension rotation center portion 21 in the vehicle vertical position relationship. Therefore, the lower connecting portion 24 extends from the suspension rotation center portion 21 to the lower support portion 25L while being slightly inclined downward in the device as it goes toward the front of the device. Further, here, as shown in FIG. 5A, the lower support portion 25L is located outside the suspension rotation center portion 21 in the device in the positional relationship in the device width direction. Therefore, the lower connecting portion 24 extends from the suspension rotation center portion 21 once toward the front of the device, and then extends while changing the direction outward in the device width direction.

(Vertical connection part 26)
A vertical connecting portion 26 is provided so as to vertically connect the device front part of the upper support part 25U and the device front part of the lower support part 25L. As a result, the suspension arm 20 is formed with an opening 27 that opens in a side view as seen from the device width direction shown in FIG. 5B. In other words, the suspension rotation center portion 21, the upper connecting portion 22, the lower connecting portion 24, and the vertical connecting portion 26 form the suspension arm 20 in a substantially rectangular frame shape in a side view. The linear actuator 40, which will be described later, is arranged so as to pass through the opening 27.

(Actuator support 29)
A spanning member 28 is attached so as to bridge an intermediate portion in the vertical direction of the opening 27 in the front-rear direction of the apparatus. The hanging member 28 is formed in a substantially rod shape, the end portion on the device rear side is fastened to the inside of the standing portion 22H of the upper coupling portion 22 in the device, and the end portion on the device front side is the vertical coupling portion 26. It is fastened inside the device.

The linear actuator 40 is inserted into the gap above the spanning member 28 and below the upper wall portion 22W of the upper coupling portion 22. Furthermore, the linear motion actuator 40 is supported in the vertical direction of the device at the inserted portion. The linear actuator 40 is rotatably supported by the suspension arm 20, and its rotation axis (actuator rotation axis B) is substantially aligned with the vertical direction of the apparatus. Hereinafter, the portion of the suspension arm 20 that supports the linear actuator 40 is referred to as an actuator support portion 29.

Further, the lower portion of the vertical connecting portion 26 is an absorber supporting portion 26L to which a shock absorber 50 described later is connected. A through hole 26LA extending in the front-rear direction of the device is formed in the absorber supporting portion 26L, and one end portion 50A of the shock absorber 50 is inserted into the through hole 26LA to be connected (FIG. 3). reference).

The suspension arm 20 configured as described above supports the tire hub unit 30 so as to be rotatable about the steering rotation axis C, and the linear motion actuator 40 (the drive unit 43 as the “arm support unit”) of the actuator. It is rotatably supported about the rotation axis B.

<Direct acting actuator 40>
The linear actuator 40 includes a base portion 41 and a linear movement portion 42 each formed in a rod shape, and a drive portion 43 that linearly moves the linear movement portion 42 with respect to the base portion 41. The base portion 41 has a cylindrical shape, and has a configuration in which a part of the linear motion portion 42 is inserted inside the base portion 41. The drive unit 43 includes a motor and a ball screw (not shown), and converts the rotational movement of the motor into a linear movement of the linear movement unit 42 with respect to the base 41 by the ball screw. The drive unit 43 is electrically connected to a steering input device such as a steering wheel, and the linear motion actuator 40 is controlled to expand and contract according to the operation of the steering input device.

The positional relationship between the drive unit 43 and the base 41 is fixed, while the linear motion unit 42 moves linearly with respect to the drive unit 43 and the base 41. The drive unit 43 is rotatably supported by the actuator support unit 29 of the suspension arm 20 described above. On the other hand, the front end portion 42A of the linear motion portion 42 is rotatably supported by the steering rotational force point portion 39 of the tire hub unit 30, and its rotation axis (power point axis A) is substantially aligned with the vertical direction of the device. .. In the present embodiment, the drive portion 43 corresponds to the “arm support portion” of the present invention, and the tip end portion 42A of the linear motion portion 42 corresponds to the “tire support portion” of the present invention.

<Aspect in which the shock absorber 50 and the mounting member 60 are mounted>
3, 4, and 5 show a steering device 10 that further includes a mounting member 60 and a shock absorber 50 in addition to the configuration shown in FIG. 1 described above. The tire hub unit 30 is not shown in FIG. 3, and the rolling portion 32 of the tire hub unit 30 is not shown in FIG.

The attachment member 60 is formed in a plate shape and is directly fixed to the vehicle body 100 (see FIG. 6A), and the suspension rotation center of the suspension arm 20 is fixed to the plate portion 61. It is configured to include a pair of suspension connecting portions 62 that are rotatably connected to the portion 21. Further, the mounting member 60 is configured to include an absorber connecting portion 63 that is fixed to the plate-shaped portion 61 and that connects the shock absorber 50 and the plate-shaped portion 61.

The shock absorber 50 extends in the front-rear direction of the device in a plan view as shown in FIG. 5(A), and is slightly inclined with respect to the horizontal direction in a side view as shown in FIG. 5(B). It is arranged. The shock absorber 50 has one end (the front end 50A of the device) rotatably supported by the suspension arm 20, and the other end (the rear end 50B of the device) rotated by the absorber connecting portion 63 of the mounting member 60. Supported as possible. The direction of the rotation axis is substantially the same as the device width direction.

A portion of the shock absorber 50 on which one end 50A is supported is an absorber support portion 26L formed at a substantially front end of the suspension arm 20. The absorber support portion 26L substantially coincides with the center of the tire hub unit 30 in the positional relationship in the device front-rear direction. Further, as shown in FIG. 5B, the absorber support portion 26L of the suspension arm 20 is located above the lower support portion 25L of the suspension arm 20 in the positional relationship in the device vertical direction, and the absorber support portion 26L of the tire hub unit 30. It is located below the center (axle).

The absorber connecting portion 63 of the mounting member 60 is located below the upper support portion 25U of the suspension arm 20 and above the center (axle) of the tire hub unit 30 in the positional relationship in the device vertical direction. The absorber connecting portion 63 of the mounting member 60 is located below the linear actuator 40 in the vertical positional relationship.

FIG. 6 is a diagram for explaining a mounting mode of the steering device 10 on the vehicle body 100 described above. The left part of the direction is shown. FIG. 6A shows a state in which only the plate-shaped portion 61 of the attachment member 60 is attached to the vehicle body 100. Further, FIG. 6B shows a state in which the steering device 10 is attached to the vehicle body 100.

As shown in FIG. 6A, the vehicle body 100 includes a vehicle interior frame 110 that forms a vehicle interior (cabin), a front frame 120 that forms a vehicle front side of the vehicle interior, and a vehicle rear side of the vehicle interior. It is configured to include a rear frame (not shown) that constitutes the rear frame.

The vehicle interior frame 110 includes a lower side portion 111 that extends in the vehicle width direction at its front end and a lower end, and a vertical piece portion 112 that extends in the vehicle vertical direction at a position slightly inside from the vehicle width direction outer end of the lower side portion 111. , Is included. The plate-shaped portion 61 of the mounting member 60 is fixed to the lower side portion 111 and the vertical piece portion 112. Specifically, it is fixed to the lower side portion 111 at both ends of the plate-shaped portion 61 in the width direction, and is fixed to the vertical piece portion 112 at the upper end of the plate-shaped portion 61. The position of the plate-shaped portion 61 fixed to the vertical piece portion 112 is a position that overlaps with the absorber connecting portion 63 when viewed from the vehicle front-rear direction. Further, the position of the plate-shaped portion 61 fixed to the lower side portion 111 is a position that overlaps with the pair of suspension connecting portions 62 when viewed from the vehicle front-rear direction.

As shown in FIG. 6B, when the steering device 10 is attached to the vehicle interior frame 110 (vehicle body 100) as front wheels, the front-rear direction of the steering device 10 coincides with the front-rear direction of the vehicle, and the width direction of the device is the same. The outer side corresponds to the vehicle width direction outer side, and the device vertical direction corresponds to the vehicle vertical direction. However, when the steering device 10 is attached to the vehicle interior frame 110 as rear wheels, the front-rear direction of the device and the front-rear direction of the vehicle have an inverse relationship.

The steering device 10 is also attached to the vehicle front and the vehicle width direction right side of the vehicle interior frame 110, the vehicle rear and the vehicle width direction left side, and the vehicle rear and vehicle width direction right side. In addition, among these, when it is attached to the vehicle front side and the vehicle width direction right side and the vehicle rear side and the vehicle width direction left side, it is necessary to make the above-described steering device 10 symmetrical in the device width direction. That is, since the steering device 10 is configured as one module having a steering function and a driving function, a plurality (for example, four) of the same steering devices 10 can be prepared and applied to a vehicle.

Further, when the steering device 10 is attached to the vehicle front part of the vehicle interior frame 110, that is, when the steering device 10 functions as front wheels, the suspension system is the leading arm system. On the other hand, when the steering device 10 is attached to the vehicle rear portion of the vehicle interior frame 110, that is, when the steering device 10 functions as a rear wheel, the suspension system is a tracing arm system.

Further, as shown in FIG. 6B, the front frame 120 of the vehicle body 100 includes front side members 121 that extend in front of the vehicle interior frame 110 in a substantially front-rear direction of the vehicle. A pair of front side members 121 are provided side by side in the vehicle width direction (only the vehicle left side is shown in FIG. 6 ), and are provided so as to be inclined outward in the vehicle width direction toward the front of the vehicle. The steering device 10 is attached to the front side member 121 on the outer side in the vehicle width direction.

In the straight traveling state shown in FIG. 6B, the linear motion actuator 40 of the steering device 10 is substantially parallel to the front side member 121. Further, as shown in FIGS. 2A to 2C, when the steering state of the steering device 10 is changed, the linear actuator 40 swings, but the linear actuator 40 and the front side member 121 are separated from each other. It does not interfere.

<Action/effect>
Next, the operation and effect of the steering device 10 of the present embodiment will be described.

In the steering device 10 of the present embodiment, the suspension hub 20 supports the tire hub unit 30. The tire hub unit 30 is rotatable around the steering rotation axis C.

The steering device 10 also includes a linear actuator 40 that expands and contracts based on the operation of the steering input device. The linear motion actuator 40 is a linear motion part as a “tire support part” in which the distance between the driving part 43 as an “arm support part” and the arm support part (driving part 43) changes due to expansion and contraction of the linear motion actuator 40. The front end portion 42A of 42 is included. Of these, the arm support portion is rotatably (actuator rotation axis B) supported by the suspension arm 20. On the other hand, the tire support portion is rotatably (power point axis A) supported by the tire hub unit 30.
Therefore, as the linear motion actuator 40 expands and contracts based on the operation of the steering input device, the tire hub unit 30 rotates about the steering rotation axis C with respect to the suspension arm 20. That is, the tire hub unit 30 can be steered by operating the steering input device.

Specifically, as the linear actuator 40 extends from the straight traveling state shown in FIG. 2(B), the tire hub unit 30 is steered outward as shown in FIG. 2(A). Further, as the linear actuator 40 contracts from the straight traveling state, the tire hub unit 30 is steered inward as shown in FIG. 2(C). At this time, the linear motion actuator 40 swings.

FIG. 2A shows a state in which the tire hub unit 30 is steered to the maximum outward (outer maximum steering state), and in this outer maximum steering state, the direction in which the tire hub unit 30 faces (FIG. 2). (See arrow T) and the longitudinal direction of the linear motion actuator 40 are substantially parallel to each other. Further, FIG. 2C shows a state where the tire hub unit 30 is steered to the inside (maximum inside steering state), and in this inside maximum steering state, the direction in which the tire hub unit 30 faces ( The arrow T in FIG. 2) and the longitudinal direction of the linear actuator 40 have a substantially right angle relationship.

Further, since the linear actuator 40 is rotatably supported by both the arm support portion (driving portion 43) and the tire support portion 40A (tip portion 42A of the linear movement portion 42), the linear actuator 40 has No lateral load other than the load in the linear direction acts. Therefore, compared to the case where a lateral load acts on the linear motion actuator, it is less necessary to secure the rigidity of the linear motion actuator 40 against the lateral load. Therefore, the linear motion actuator 40 only needs to have a rigidity that does not buckle with respect to the load in the linear motion direction, so that the linear motion actuator 40 can be designed to be lightweight.

Further, as described above, the linear motion actuator 40 is supported by both the drive section 43 and the tire support section 40A. Therefore, when mounting the steering device 10 on the vehicle body 100, the suspension arm 20 may be mounted on the vehicle body 100, and it is not necessary to directly mount the linear motion actuator 40 on the vehicle body 100. Therefore, the assemblability is high.

Further, in the steering device 10 of the present embodiment, the longitudinal direction of the linear motion actuator 40 is changed to the expanded/contracted state (in other words, the steering state of the steering device 10) as shown in FIGS. 2(A) to 2(C). However, it is set to the front of the device and the diagonal direction outside the device in the width direction. Therefore, the dimension of the steering device 10 in the width direction can be designed to be smaller than that in the case where the linear motion actuator 40 is provided so that its longitudinal direction faces the device width direction. Therefore, it is easy to secure the space in the central portion in the width direction of the vehicle when it is attached to the vehicle body 100.

Further, in the steering system 10 of the present embodiment, the suspension arm 20 is provided with the opening 27 that penetrates in the device width direction. The linear actuator 40 is inserted through the opening 27, and the drive portion 43 of the linear actuator 40 is arranged in the opening 27. The arm support portion (drive portion 43) of the linear motion actuator 40 is supported by the suspension arm 20 at the upper and lower portions thereof.
Therefore, it is possible to prevent a moment from being generated in the suspension arm 20 due to the load input from the linear motion actuator 40. Therefore, the space occupancy of the steering device 10 can be kept low while maintaining the rigidity of the suspension arm 20.

Further, in the steering device 10 of the present embodiment, in the straight traveling state shown in FIG. 2(B), the tire support portion of the linear motion actuator 40 (the tip end portion 42A of the linear motion portion 42) is located in front of the steering rotation axis C. Is located in. Therefore, as shown in FIG. 2C, the linear actuator 40 contracts, whereby a large steering angle inward in the device width direction can be realized.

Further, in the steering apparatus 10 of the present embodiment, in the outer maximum steering state shown in FIG. 2A, the direction in which the tire hub unit 30 faces (see arrow T in FIG. 2) and the longitudinal direction of the linear actuator 40. And have a substantially parallel relationship. For this reason, it is easy to set the positional relationship between the tire hub unit 30 and the linear motion actuator 40 such that the distance between the tire hub unit 30 and the linear motion actuator 40 becomes narrow in the maximum outer steering state. Therefore, the space occupancy rate of the steering device 10 can be further suppressed.

The steering system 10 of the present embodiment also includes a shock absorber 50 that connects the suspension arm 20 and the vehicle body 100. The shock absorber 50 intersects the linear motion actuator 40 in a plan view and is arranged below the linear motion actuator 40.
Therefore, even when the steering device 10 includes the shock absorber 50, the space occupancy rate of the entire steering device 10 can be efficiently suppressed to be low.

The steering device 10 of the present embodiment also includes a mounting member 60 fixed to the vehicle body 100. The suspension rotation center 21 of the suspension arm 20 is rotatably (swingably) supported by the mounting member 60, and the other end of the shock absorber 50 is connected to the absorber support 26L of the suspension arm 20 at one end 50A. The part 50B is connected.
Therefore, the steering device 10 can be assembled to the vehicle body 100 by fixing the mounting member 60 to the vehicle body 100. That is, it is not necessary to separately attach the other end 50B of the shock absorber 50 to the vehicle body 100. Therefore, the assemblability is high.

Further, the steering device 10 of the present embodiment is attached to the front portion or the rear portion of the vehicle body 100. When attached to the front portion of the vehicle body 100, the steering system 10 is a leading arm type suspension system, and is attached to the rear portion of the vehicle body 100. If installed, it is a trailing arm suspension system. For this reason, it is easy to attach the steering device 10 near the vehicle interior frame 110, which is a portion of the vehicle body 100 that constitutes the vehicle interior. Here, in general, the portion forming the vehicle interior is often designed with relatively high rigidity in the entire vehicle body. Therefore, according to the present embodiment, it is easy to attach the steering device 10 to the vehicle body 100 with high rigidity.

[Supplementary explanation of the above embodiment]
In the above embodiment, the linear actuator 40 is an actuator configured to convert the rotational movement of the motor into a linear movement by a ball screw, but the present invention is not limited to this. An actuator that expands and contracts based on the operation of a steering input device such as a steering wheel may be used. For example, the linear motion actuator may include a motor and a wire, and the wire may be contracted by winding the wire by the rotational movement of the motor. In this case, an elastic member such as a spring applies tension to the wire so that the wire does not bend.

Further, in the above-described embodiment, the example in which the suspension type with the steering device 10 attached is the leading arm type or the trailing arm type has been described, but the present invention is not limited to this. For example, a semi-trailing arm system may be used, or another system may be used.

10 Steer-by-Wire Steering Device 20 Suspension Arm 21 Suspension Rotation Center 25 Tire Support 25L Lower Support 25U Upper Support 26L Absorber Support 27 Opening 29 Actuator Support 30 Tire Hub Unit 36 Steering Rotation Force Point 40 Direct Actuator 41 base 42 linear motion part 42A tip part of linear motion part (tire support part)
43 Drive Unit (Arm Support Unit)
50 shock absorber 50A one end portion 50B other end portion 60 mounting member 61 plate portion 62 suspension connection portion 63 absorber connection portion 100 vehicle body 110 vehicle interior frame A force point axis B actuator rotation axis C steering rotation axis D axle axis E suspension rotation center axis FR Front and rear direction of the device OUT OUT side of the device width direction UP Upper and lower direction of the device T T direction in which the tire hub unit faces

Claims (7)

Suspension arm,
A tire hub unit supported by the suspension arm so as to be rotatable around a steering rotation axis;
A linear actuator that expands and contracts based on the operation of the steering input device,
A steer-by-wire type steering device comprising:
The linear actuator is
An arm support portion rotatably supported by the suspension arm,
While being rotatably supported by the tire hub unit, a tire support portion whose distance from the arm support portion changes due to expansion and contraction of the linear actuator,
It is configured to include a
The suspension arm has an opening penetrating in the device width direction,
The linear actuator is inserted through the opening, and is supported by the suspension arm at an upper portion and a lower portion of the linear actuator.
Steer-by-wire steering system. The longitudinal direction of the linear actuator is, regardless of the expansion/contraction state thereof, an oblique direction in front of the device and outside in the device width direction,
The steer-by-wire type steering device according to claim 1. In the straight traveling state, the tire support portion of the linear motion actuator is located in front of the device with respect to the steering rotation shaft,
The steer-by-wire type steering device according to claim 1 . In the outer maximum steering state, the direction in which the tire hub unit faces and the longitudinal direction of the linear actuator have a substantially parallel relationship.
The steer-by-wire type steering device according to claim 3 . The steer-by-wire type steering device,
It further comprises a shock absorber connecting the suspension arm and the vehicle body,
The shock absorber intersects the linear actuator in a plan view,
The steer-by-wire type steering device according to claim 1 . The steer-by-wire type steering device further includes an attachment member fixed to the vehicle body,
The mounting member rotatably supports the suspension arm, and the other end of the shock absorber whose one end is connected to the suspension arm is connected to the attachment member.
The steer-by-wire type steering device according to claim 5 . The steer-by-wire type steering device is attached to a front portion or a rear portion of a vehicle body,
If it is attached to the front part of the vehicle body, it is a leading-arm suspension system, and if it is attached to the rear part of the vehicle body, it is a trailing arm system or a semi-trailing arm system suspension system.
The steer-by-wire steering apparatus according to any one of claims 1 to 6 .

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