JP7670332B2 - Steer-by-wire steering unit and assembly method thereof - Google Patents

Description

The present invention relates to a steering unit for steer-by-wire and its assembly method.

In recent years, there has been progress in the development of steer-by-wire steering devices in which the steering unit to which the steering wheel is attached and the steering unit for applying a steering angle to the steered wheels are electrically connected rather than mechanically.

A steer-by-wire steering device detects the steering angle of the steering wheel using a sensor in the steering unit, and drives the actuator of the steering unit based on the output signal of the sensor. This imparts a steering angle to a pair of steered wheels.

In a steer-by-wire steering device, the steering unit and the turning unit are mechanically separated, so the steering reaction force is not transmitted from the wheels to the steering wheel. Therefore, in order to provide the driver with a steering reaction force, a reaction force generating device equipped with an electric motor or the like is provided in the steering unit, as described in JP 2004-322715 A (Patent Document 1) and other publications.

In addition, in a steer-by-wire steering device, like a mechanical steering device in which the steering wheel and steering wheels are mechanically connected, it is necessary to adjust the front-rear position and height of the steering wheel according to the driver's physique and posture. In addition, when a steer-by-wire steering device is used in combination with autonomous driving technology, it is necessary to store the steering wheel inside the dashboard, and therefore it is necessary to displace the steering wheel significantly forward. For this reason, even in a steer-by-wire steering device, as described in JP 2020-32779 A (Patent Document 2) and the like, a position adjustment device for adjusting the position of the steering wheel is provided in the steering unit.

JP 2004-322715 A JP 2020-32779 A

The magnitude of the steering reaction force applied to the steering wheel and/or the range of adjustment of the steering wheel position often differs depending on the type of vehicle in which the steer-by-wire steering device is installed. Therefore, the entire steering unit, which includes a position adjustment device and a reaction force generating device, is custom designed for each vehicle. This increases the number of steps required to design the steering unit, causing manufacturing costs to rise.

The present invention has been made to solve the above problems, and aims to provide a steering unit for steer-by-wire that can reduce manufacturing costs.

The steer-by-wire steering unit of the present invention includes a position adjustment device, a reaction force generating device, a power connection portion, and a housing connection portion.
The position adjustment device is for adjusting a position of a steering wheel and includes a first shaft connection portion and a first housing connection portion.
The reaction force generating device is for applying a steering reaction force to the steering wheel, and has a second shaft connection portion connectable to the first shaft connection portion, and a second housing connection portion connectable to the first housing connection portion.
The power connection portion connects the first shaft connection portion and the second shaft connection portion.
The housing connection portion connects the first housing connection portion and the second housing connection portion.

In the steer-by-wire steering unit of the present invention, each of the power connection portion and the housing connection portion has a connection structure common to another steer-by-wire steering unit in which at least one of the position adjustment device and the reaction force generating device has a different configuration.
In other words, the first shaft connection portion and the first housing connection portion, which are interfaces, are common to two or more types of multiple position adjustment devices, and/or the second shaft connection portion and the second housing connection portion, which are interfaces, are common to two or more types of multiple reaction force generating devices.
In this case, the first shaft connection portion and the first housing connection portion may be common to two or more types of the plurality of position adjustment devices having different adjustable ranges for the steering wheel position, and the second shaft connection portion and the second housing connection portion may be common to two or more types of the plurality of reaction force generating devices having different magnitudes of steering reaction force that can be generated.

In the steer-by-wire steering unit of the present invention, the position adjustment device includes a steering shaft having the first shaft connection portion at its front end, a steering column having the first housing connection portion at its front end, and a rolling bearing for rotatably supporting the steering shaft inside the steering column, and the first housing connection portion and the second housing connection portion are connected by a spigot fit, and the power connection portion can be disposed between the housing connection portion and the rolling bearing in the fore-and-aft direction.

In the steer-by-wire steering unit of the present invention, the reaction force generating device has an output shaft having the second shaft connection portion at its rear end and a torque sensor arranged around the output shaft, and the first housing connection portion and the second housing connection portion are connected by a spigot fit, and the housing connection portion can be arranged in a position overlapping the torque sensor in the radial direction of the output shaft.

The steer-by-wire steering unit of the present invention can include a position adjustment device, a reaction force generating device, and a housing connection portion.
The position adjustment device is for adjusting a position of a steering wheel and has a first housing connection portion.
The reaction force generating device is for applying a steering reaction force to the steering wheel, and has a second housing connecting portion connectable to the first housing connecting portion.
The housing connection portion connects the first housing connection portion and the second housing connection portion.
The housing connection portion has a common connection structure with another steer-by-wire steering unit in which at least one of the position adjustment device and the reaction force generating device has a different configuration.
The position adjustment device includes a steering shaft and a steering column having the first housing connection portion.
The reaction force generating device has an output shaft connected to the steering shaft, and a gear housing having the second housing connection portion.
The second housing connection portion has a cylindrical second connection tube portion that is connectable to the first housing connection portion by spigot fitting.
A seal is formed between the inner peripheral surface of the second connecting cylindrical portion and the outer peripheral surface of the output shaft.
In this case, a sealing member can be provided between the inner peripheral surface of the second connecting cylindrical portion and the outer peripheral surface of the output shaft. The sealing member can be any member capable of preventing the passage of foreign matter such as grease, and a dedicated sealing device such as a seal ring (including a dust seal) or a combination seal ring can be used, or a rolling bearing having sealing performance can be used.

The method for assembling a steering unit for steer-by-wire of the present invention is a method for assembling a steering unit for steer-by-wire including a position adjustment device for adjusting the position of a steering wheel, each of which has a first shaft connection portion and a first housing connection portion, and a reaction force generating device for applying a steering reaction force to the steering wheel, each of which has a second shaft connection portion connectable to the first shaft connection portion, and a second housing connection portion connectable to the first housing connection portion.
In the assembly method for a steer-by-wire steering unit of the present invention, the position adjustment device is selected from two or more types of a plurality of position adjustment devices each having the first shaft connection portion and the first housing connection portion, and/or the reaction force generating device is selected from two or more types of a plurality of reaction force generating devices each having the second shaft connection portion and the second housing connection portion.

In the assembly method for the steer-by-wire steering unit of the present invention, the first housing connection portion and the second housing connection portion can be connected by a spigot fitting.

The present invention makes it possible to realize a steering unit for steer-by-wire that can reduce manufacturing costs.

FIG. 1 is a schematic diagram showing a steer-by-wire type steering device including a steering unit according to a first example of an embodiment. FIG. 2 is a side view showing a steering unit according to a first example of an embodiment. FIG. 3 is an end view of the steering unit according to the first example of the embodiment, as viewed from the rear side. FIG. 4 is a cross-sectional view taken along line AA of FIG. 3, showing the steering unit according to the first example of the embodiment with the bracket and the reaction force applying motor omitted. FIG. 5 is an enlarged view of the left side of FIG. FIG. 6 is a side view showing a position adjustment device constituting a steering unit according to a first example of the embodiment. FIG. 7 is a front end view of a position adjustment device constituting a steering unit according to a first example of an embodiment. FIG. 8 is a perspective view showing a position adjustment device constituting a steering unit according to a first example of an embodiment. FIG. 9 is a perspective view showing a reaction force generating device constituting a steering unit according to a first example of the embodiment, with the reaction force applying motor removed. Figure 10 is a diagram shown to explain the connection structure of the power connection part of the steering unit in the first example of the embodiment, where (A) is a partial cross-sectional view showing the state before connection, and (B) is a partial cross-sectional view showing the state after connection. FIG. 11 is an enlarged view of the upper right portion of FIG. FIG. 12 is an enlarged view of part B in FIG. FIG. 13 is a view showing a power connection portion of a steering unit according to a second example of an embodiment, and corresponds to part C in FIG. FIG. 14 is a cross-sectional view showing a power connection portion of a steering unit according to a second example of an embodiment. FIG. 15 is a cross-sectional view showing a joint member constituting a power connection portion of a steering unit according to a second example of the embodiment. FIG. 16 is an end view showing a joint member constituting a power connection portion of a steering unit according to a second example of the embodiment. FIG. 17 is a view showing a power connection portion of a steering unit according to a third example of an embodiment, and corresponds to part C in FIG. FIG. 18 is a cross-sectional view showing a power connection portion of a steering unit according to a third example of an embodiment. FIG. 19 is a cross-sectional view showing a shaft coupling constituting a power connection portion of a steering unit according to a third example of an embodiment. FIG. 20 is an end view showing a shaft coupling constituting a power connection portion of a steering unit according to a third example of the embodiment. FIG. 21 is a half sectional view corresponding to part C in FIG. 5, showing a power connection part of a steering unit according to a fourth example of an embodiment. FIG. 22 is a cross-sectional view showing an elastic cylindrical member constituting a power connection portion of a steering unit according to a fourth example of the embodiment. FIG. 23 is an end view showing an elastic cylindrical member constituting a power connection portion of a steering unit according to a fourth example of the embodiment. Figure 24 is a diagram corresponding to Figure 10 and shown to explain the power connection part of a steering unit in a fifth example of an embodiment, where (A) is a partial cross-sectional view showing the state before connection, (B) is a partial cross-sectional view showing the state after connection, and (C) is a partial cross-sectional view showing the state in which an alignment error has occurred after connection. FIG. 25 is a diagram corresponding to FIG. 12 and showing a housing connection portion of a steering unit according to a sixth example of an embodiment. FIG. 26 is a diagram corresponding to FIG. 4 and shown to explain the housing connection portion of the steering unit according to a seventh example of an embodiment. FIG. 27 is a side view showing a steering unit according to a seventh example of an embodiment with the steering column and the outer shaft omitted. FIG. 28 is an end view showing a steering unit according to a seventh example of an embodiment with the steering column and the outer shaft omitted.

[First Example of the Embodiment]
A first example of the embodiment will be described with reference to Figures 1 to 12. In the following description, the front-rear direction means the front-rear direction of the vehicle, the up-down direction means the up-down direction of the vehicle, and the width direction means the width direction of the vehicle.

[Overall configuration of steering device]
The steering device 1 of this example is a steer-by-wire type steering device. As shown in the overall configuration in Fig. 1, the steering device 1 includes a steering unit 3 to which a steering wheel 2 is attached, a steering unit 5 that steers a pair of steered wheels 4, and a control device (ECU) 6. The steering device 1 has a linkless structure in which the steering unit 3 and the steering unit 5 are not mechanically connected but are electrically connected.

The steering unit 3 measures the operation of the steering wheel 2 by the driver using a torque sensor 75 (see FIG. 5) and a steering angle sensor (not shown), and outputs the measurement results to the control device 6. Various signals indicating the driving situation, such as the steering torque measured by the torque sensor 75, the steering angle measured by the steering angle sensor, vehicle speed, yaw rate, and acceleration, are input to the control device 6. The control device 6 drives the steering actuator 7 provided in the steering unit 5 based on the various signals indicating the driving situation. This displaces linear motion members such as the rack shaft and screw shaft in the width direction, pushing and pulling a pair of tie rods 8 to impart a steering angle to the pair of steered wheels 4.

The control device 6 also controls the drive of a reaction force applying motor 58 (see FIG. 3) of a reaction force generating device 10 (described later) provided in the steering unit 3 based on various signals indicating driving conditions such as steering torque, steering angle, and vehicle speed, and applies a steering reaction force to the steering wheel 2 according to the driving conditions.

[Steering unit]
Next, a description will be given of the steering unit 3, which is a characteristic part of the steering device 1 of this embodiment. The steering unit 3 includes a position adjustment device 9 for adjusting the position of the steering wheel 2, and a reaction force generating device 10 for applying a steering reaction force to the steering wheel 2.

The position adjustment device 9 and the reaction force generating device 10 are each sub-assembled and connected to each other by two connection parts. Specifically, the position adjustment device 9 and the reaction force generating device 10 arranged in front of the position adjustment device 9 are connected to each other only at two points, the power connection part 11 and the housing connection part 12, as shown in Figures 4 and 5. Therefore, the steering unit 3 in this example is assembled by connecting the position adjustment device 9 and the reaction force generating device 10 at two points, the power connection part 11 and the housing connection part 12. In particular, in this example, the connection structures of the power connection part 11 and the housing connection part 12 have been devised.

The power connection unit 11 is not a dedicated connection structure for connecting the position adjustment device 9 and the reaction force generating device 10 constituting the steering unit 3 of this example, but has a common connection structure with a steering unit other than the steering unit 3 of this example in which at least one of the position adjustment device 9 and the reaction force generating device 10 has a different configuration. For example, the power connection unit 11 has a common connection structure with the power connection unit of another steering unit equipped with another position adjustment device in which the position adjustment range of the steering wheel 2 is different from that of the position adjustment device 9 of this example, and the same reaction force generating device 10 as in this example. Alternatively, the power connection unit 11 has a common connection structure with the power connection unit of another steering unit equipped with the same position adjustment device 9 as in this example, and another reaction force generating device in which the magnitude of the steering reaction force that can be generated is different from that of the reaction force generating device 10 of this example. Alternatively, the power connection section 11 has a common connection structure with the power connection section of another steering unit that includes another position adjustment device in which the position adjustment range of the steering wheel 2 is different from that of the position adjustment device 9 of this example, and another reaction force generating device in which the magnitude of the steering reaction force that can be generated is different from that of the reaction force generating device 10 of this example. Note that structures with different position adjustment ranges include not only structures with different adjustable lengths, but also structures with different adjustable directions.

The housing connection part 12 is also not a dedicated connection structure for connecting the position adjustment device 9 and the reaction force generating device 10 constituting the steering unit 3 of this example, but has a common connection structure with a steering unit other than the steering unit 3 of this example in which at least one of the position adjustment device 9 and the reaction force generating device 10 has a different configuration. For example, the housing connection part 12 has a common connection structure with a housing connection part of another steering unit including another position adjustment device whose position adjustable range of the steering wheel 2 is different from that of the position adjustment device 9 of this example, and the same reaction force generating device 10 as in this example. Alternatively, the housing connection part 12 has a common connection structure with a housing connection part of another steering unit including the same position adjustment device 9 as in this example, and another reaction force generating device whose magnitude of the steering reaction force that can be generated is different from that of the reaction force generating device 10 of this example. Alternatively, the housing connection portion 12 has a common connection structure with the housing connection portion of another steering unit that has another position adjustment device in which the position adjustment range of the steering wheel 2 is different from that of the position adjustment device 9 of this example, and another reaction force generating device in which the magnitude of the steering reaction force that can be generated is different from that of the reaction force generating device 10 of this example.
A detailed explanation of the connection structure of the power connection part 11 and the housing connection part 12 will be given after the explanation of the position adjustment device 9 and the reaction force generating device 10, respectively.

Position Adjustment Device
The position adjustment device 9 has a function of adjusting the front-rear position and the up-down position of the steering wheel 2. In other words, the position adjustment device 9 has a telescopic mechanism for adjusting the front-rear position of the steering wheel 2, and a tilt mechanism for adjusting the up-down position of the steering wheel 2.

The position adjustment device 9 includes a steering shaft 13, a steering column 14, a lower telescopic actuator 15, an upper telescopic actuator 16, and a tilt actuator 17.

<Steering shaft>
The steering shaft 13 is configured so that its entire length can be extended and contracted, and is rotatably supported inside the steering column 14 by a plurality of (three in the illustrated example) rolling bearings 18a to 18c. The steering wheel 2 is attached to the rear end of the steering shaft 13. The steering shaft 13 is formed by spline-engaging a lower shaft 19 disposed at the front side with a hollow cylindrical upper shaft 20 disposed at the rear side to enable torque transmission and relative axial displacement.

<<First shaft connection part>>
A first shaft connection portion 21 is provided at the front end of the lower shaft 19, which constitutes the power connection portion 11 capable of transmitting torque to the reaction force generating device 10. The first shaft connection portion 21 has a structure that is common to two or more types of position adjustment devices that have different adjustable ranges for the position of the steering wheel, for example.

In this example, the first shaft connection part 21 is a female spline part, and the connection structure of the power connection part 11 is a spline structure. In particular, in this example, the first shaft connection part 21 has a semispherical female spline structure in which a plurality of female spline teeth 23 are formed in the radial direction on the inner surface of a semispherical recess 22 that opens into the front end face of the lower shaft 19, as shown in FIG. 10 (A). However, as the first shaft connection part, a general female spline structure or female serration structure can also be adopted in which a cylindrical part is formed at the front end of the lower shaft, and a plurality of female spline teeth or female serration teeth are formed in the axial direction on the inner peripheral surface of the cylindrical part.

Steering column
The steering column 14 is configured to be extendable over its entire length and is supported by a vehicle body (not shown). The steering column 14 includes a bracket 24 and a column body 25. The steering column 14 in this example has a two-stage telescopic structure to ensure a large amount of telescopic movement in the front-rear direction.

The bracket 24 is used to support the column body 25 on the vehicle body, and includes a fixed bracket 26 that is fixed to the vehicle body, and a displacement bracket 27 that is supported so as to be displaceable relative to the fixed bracket 26 in the fore-and-aft direction.

The fixed bracket 26 comprises a fixed plate portion 28 having a substantially rectangular flat shape and a fixed side support frame 29 having a substantially U-shape. The fixed plate portion 28 is fixed to the vehicle body using a number of mounting bolts 30. The fixed side support frame 29 is provided at the front end of the fixed plate portion 28 and connects both ends of the fixed plate portion 28 in the width direction.

The displacement bracket 27 comprises a displacement plate portion 31 arranged so as to be superimposed on the underside of the fixed plate portion 28, and a displacement side support frame 32 having a generally U-shape. The displacement plate portion 31 is supported by a linear guide 94 (see FIG. 3) so as to be capable of relative displacement in the front-rear direction with respect to the fixed plate portion 28. The displacement side support frame 32 is provided at the rear end of the displacement plate portion 31 and connects both ends of the displacement plate portion 31 in the width direction. Of the pair of left and right support walls 33 constituting the displacement side support frame 32, a screw shaft (not shown) of the tilt feed screw device 56 constituting the tilt actuator 17 is supported on the inner surface of one of the support walls 33 so as to be rotatable with its axial direction facing up and down.

As shown in FIG. 4, the column body 25 is generally cylindrical in shape and is disposed with its axial direction in the front-rear direction. The column body 25 includes an outer column 34 disposed in the middle in the front-rear direction, a lower inner column 35 fitted into the front side of the outer column 34, and an upper inner column 36 fitted into the rear side of the outer column 34.

The outer column 34 is supported so as to be movable in the vertical direction relative to the displacement bracket 27. The rear side of the outer column 34 is inserted in the front-rear direction inside the displacement side support frame 32 that constitutes the displacement bracket 27. A nut (not shown) of the tilt feed screw device 56 that constitutes the tilt actuator 17 is pivotally supported on the outer peripheral surface of the rear side of the outer column 34. The outer column 34 has a slit 37 (see FIG. 4) that extends in the front-rear direction at the middle part of the lower surface in the front-rear direction. The outer column 34 has screw holes 38 at multiple locations on the outer peripheral surface. Each screw hole 38 is screwed with a screw plug 39 whose tip is made of a material with a low friction coefficient such as polyacetal (POM).

The lower-side inner column 35 is fitted into the front side of the outer column 34 so as to allow relative displacement in the front-rear direction. The tip of a screw plug 39 that is screwed into a screw hole 38 provided in the outer column 34 is pressed against the outer peripheral surface of the lower-side inner column 35. This suppresses rattling of the lower-side inner column 35 relative to the outer column 34. The lower-side inner column 35 has a cylindrical portion 40 that is arranged inside the outer column 34, and a first housing connection portion 41 that is fitted into and supported by the front end portion of the cylindrical portion 40.

<<First housing connection part>>
The first housing connection portion 41 has a structure common to two or more position adjustment devices having different adjustable ranges of the steering wheel position. In this example, the first housing connection portion 41 has a cylindrical first connection tube portion 42 fitted into the front end of the cylindrical portion 40, and a first connection plate portion 43 bent radially outward from the front end of the first connection tube portion 42 and having an outward flange shape and a substantially rectangular flat plate shape. Each corner of the first connection plate portion 43 is provided with a first through hole 44 penetrating in the front-rear direction. The first housing connection portion 41 is disposed inside the fixed side support frame 29. The first through hole 44 may be a simple through hole or a screw hole. The first housing connection portion 41 is disposed at the front end of the column main body 25 before the position adjustment device 9 and the reaction force generating device 10 are connected, and therefore functions as a cover when the position adjustment device 9 is delivered or assembled, and can prevent foreign matter from entering the inside of the column main body 25.

The upper inner column 36 is fitted into the rear side of the outer column 34 so as to allow relative displacement in the front-to-rear direction. The tip of a screw plug 39 that is screwed into a screw hole 38 provided in the outer column 34 is pressed against the outer peripheral surface of the upper inner column 36. This prevents the upper inner column 36 from rattling relative to the outer column 34.

<Lower telescopic actuator>
The lower-side telescopic actuator 15 is disposed so as to span between the fixed bracket 26 and the displacement bracket 27 that constitute the bracket 24, and displaces the displacement bracket 27 in the front-rear direction relative to the fixed bracket 26. This causes the outer column 34 and the lower-side inner column 35 that constitute the column body 25 to be relatively displaced in the front-rear direction, causing the column body 25 to expand and contract.

The lower telescopic actuator 15 includes a lower telescopic motor 45 and a lower feed screw device 46.

The lower telescopic motor 45 is supported and fixed to the widthwise side of the fixed support frame 29 that constitutes the fixed bracket 26, with the motor output shaft (not shown) facing up and down.

As shown in FIG. 3, the lower side feed screw device 46 includes a lower side screw shaft 47 and a lower side nut 48. The lower side screw shaft 47 is arranged with its axial direction facing the front-rear direction, and is rotated by the lower side telescopic motor 45 via a reduction mechanism such as a worm reducer (not shown). The lower side screw shaft 47 is supported by the fixed bracket 26 so that it can only rotate. The lower side nut 48 is screwed into the lower side screw shaft 47 and is supported by the side surface of the displacement bracket 27 in the width direction. That is, the lower side telescopic actuator 15 rotates the lower side telescopic motor 45 to displace the lower side nut 48 in the axial direction of the lower side screw shaft 47, thereby displacing the outer column 34 in the front-rear direction relative to the lower side inner column 35.

<Upper telescopic actuator>
The upper telescopic actuator 16 is disposed so as to bridge between the outer column 34 and the upper inner column 36 that constitute the column body 25, and displaces the upper inner column 36 in the front-rear direction relative to the outer column 34. This causes the column body 25 to extend and retract.

The upper telescopic actuator 16 includes an upper telescopic motor 49 and an upper feed screw device 50.

The upper telescopic motor 49 is supported below the front end of the outer column 34 with the motor output shaft (not shown) facing in the width direction.

As shown in FIG. 3, the upper side feed screw device 50 includes an upper side screw shaft 51 and an upper side nut 52. The upper side screw shaft 51 is arranged with its axial direction facing the front-rear direction, and is rotated by the upper side telescopic motor 49 via a reduction mechanism such as a worm reducer (not shown). The upper side screw shaft 51 is supported so as to be rotatable only with respect to the outer column 34. The upper side nut 52 is screwed to the upper side screw shaft 51, and is supported on the lower surface of the upper side inner column 36 via a connector member 53. The connector member 53 is disposed inside the slit 37 of the outer column 34 and fixed to the lower surface of the upper side inner column 36. That is, the upper side telescopic actuator 16 rotates the upper side telescopic motor 49 to displace the upper side nut 52 in the axial direction of the upper side screw shaft 51, thereby displacing the upper side inner column 36 in the front-rear direction relative to the outer column 34.

<Tilt actuator>
The tilt actuator 17 is disposed so as to span between the displacement side support frame 32 and the outer column 34 that constitute the displacement bracket 27, and displaces the outer column 34 in the vertical direction relative to the displacement bracket 27. In addition, as will be described later, the reaction force generating device 10 connected to the front side of the position adjustment device 9 is rotatably supported by a pair of pivot bolts 54 disposed in the width direction relative to the fixed side support frame 29. This makes it possible to swing the column body 25 in the vertical direction relative to the bracket 24 around the pivot bolts 54.

The tilt actuator 17 includes a tilt motor 55 and a tilt feed screw device 56.

The tilt motor 55 is fixed to one of the support walls 33 that constitute the displacement side support frame 32, with the motor output shaft (not shown) facing forward and backward.

The tilt feed screw device 56 includes a tilt screw shaft and a tilt nut (not shown). The tilt screw shaft is arranged with its axial direction facing the vertical direction, and is rotated by the tilt motor 55 via a reduction mechanism such as a worm reducer (not shown). The tilt screw shaft is supported on one of the support walls 33 so that it can only rotate. The tilt nut is screwed onto the tilt screw shaft and is pivotally supported on the side surface of the outer column 34 in the width direction. That is, the tilt actuator 17 rotates the tilt motor 55 to displace the tilt nut in the axial direction of the tilt screw shaft, thereby displacing the outer column 34 in the vertical direction relative to the displacement bracket 27.

How to adjust the steering wheel position
To adjust the longitudinal position of the steering wheel 2 by the position adjustment device 9 of this example, the lower telescopic actuator 15 is driven to displace the displacement bracket 27 relative to the fixed bracket 26 in the longitudinal direction and to displace the outer column 34 relative to the lower inner column 35 in the longitudinal direction, and/or the upper telescopic actuator 16 is driven to displace the upper inner column 36 relative to the outer column 34 in the longitudinal direction. This causes the overall length of the steering column 14 to expand and contract, and also the overall length of the steering shaft 13 to expand and contract, thereby adjusting the longitudinal position of the steering wheel 2. After the longitudinal position of the steering wheel 2 has been adjusted to the desired position, the drive of the lower telescopic actuator 15 and/or the upper telescopic actuator 16 is stopped.

To adjust the vertical position of the steering wheel 2 using the position adjustment device 9 of this example, the tilt actuator 17 is driven to displace the rear portion of the outer column 34 vertically relative to the displacement bracket 27. This causes the steering shaft 13, which is rotatably supported inside the column body 25, to swing, adjusting the vertical position of the steering wheel 2. After the vertical position of the steering wheel 2 has been adjusted to the desired position, the drive of the tilt actuator 17 is stopped.

The adjustment of the fore-aft position and the up-down position of the steering wheel 2 can be performed simultaneously or independently (at different times).

<Reaction force generating device>
The reaction force generating device 10 is disposed in front of the position adjustment device 9, and is connected to the position adjustment device 9 by a power connection part 11 and a housing connection part 12. The reaction force generating device 10 is controlled by the control device 6, and applies to the steering wheel 2 a steering reaction force of a magnitude and direction according to driving conditions such as the steering angle of the steering wheel 2 and the vehicle speed.

The reaction force generating device 10 includes a gear housing 57, a reaction force applying motor 58, a worm reduction gear 59, and a connecting shaft 60.

9, the gear housing 57 includes a lower housing 61, an upper housing 62, and a second housing connection portion 63. The lower housing 61, the upper housing 62, and the second housing connection portion 63 are connected in the front-rear direction by bolts 95 before the reaction force generating device 10 is connected to the position adjustment device 9. The lower housing 61 is integrally provided with a cup-shaped worm accommodating portion 65 and a cylindrical worm wheel accommodating portion 66. The upper housing 62 is cylindrical and is fixed to the rear side of the worm wheel accommodating portion 66. Both widthwise sides of the upper housing 62 are rotatably supported by a pair of pivot bolts 54 relative to the fixed support frame 29.

<<Second housing connection part>>
The second housing connection portion 63 has a structure common to two or more types of reaction force generating devices that have different magnitudes of steering reaction force that can be generated. In this example, the second housing connection portion 63 is a so-called sensor cover that closes the rear opening of the upper housing 62, and has a cylindrical second connection tube portion 67 and a second connection plate portion 68 that is bent radially outward from the front end of the second connection tube portion 67 and has an outward flange shape and a substantially rectangular flat plate shape. Each corner of the second connection plate portion 68 is provided with a second through hole 69 that penetrates in the front-rear direction. In this example, auxiliary through holes (not shown) that penetrate in the front-rear direction are provided in the lower housing 61 and the upper housing 62 in the portions that match the second through holes 69 (in the illustrated example, two upper positions of the portions). Therefore, when the lower housing 61, the upper housing 62, and the second housing connection portion 63 are connected in the front-rear direction by the bolt 95 to form the gear housing 57, the second through hole 69 and the auxiliary through hole are continuous in the front-rear direction to form one continuous hole 79. The second through hole 69 may be a simple through hole or a screw hole. The lower housing 61 and the upper housing 62 are connected to each other by a bolt 101 inserted through the auxiliary through hole from the front to the rear.

The reaction force applying motor 58 is supported and fixed to the worm housing 65 that constitutes the gear housing 57. The rotation of the reaction force applying motor 58 is transmitted to the steering shaft 13 via the worm reduction gear 59, the connecting shaft 60, and the power connection part 11.

The worm reducer 59 includes a worm 70 and a worm wheel 71. The worm 70 is supported rotatably inside the worm housing 65 and is connected to a motor output shaft (not shown) of the reaction force applying motor 58. The worm wheel 71 is disposed inside the lower housing 61 and is fitted onto the input shaft 72 (described below) that constitutes the connecting shaft 60.

The connecting shaft 60 is disposed with its axial direction directed in the front-rear direction, and is rotatably supported inside the gear housing 57 via a plurality of ( three in the illustrated example) rolling bearings 96a, 96b , and 96c . The connecting shaft 60 includes an input shaft 72, an output shaft 73, and a torsion bar 74. The input shaft 72 and the output shaft 73 are disposed coaxially with each other, and are connected to each other via the torsion bar 74. A torque sensor 75 is disposed around the output shaft 73 for measuring the steering torque input from the driver to the steering wheel 2. The rear end of the output shaft 73 protrudes rearward from the second connecting tube portion 67 constituting the second housing connecting portion 63. The input shaft 72 is rotatably supported relative to the lower housing 61 via a rolling bearing 96a, and is rotatably supported relative to the upper housing 62 via a rolling bearing 96c. The output shaft 73 is rotatably supported by the second connecting cylindrical portion 67 that constitutes the second housing connecting portion 63 via a rolling bearing 96b.

In this example, a rolling bearing 96b having sealing performance is used to prevent foreign matter such as grease from entering the inside of the gear housing 57 from between the inner peripheral surface of the second connecting tube portion 67 and the outer peripheral surface of the output shaft 73. As a result, in this example, the inner peripheral surface of the second connecting tube portion 67 and the outer peripheral surface of the output shaft 73 are sealed. When implementing the present invention, a rolling bearing that does not have sealing performance is used as a rolling bearing for rotatably supporting the output shaft, and a dedicated sealing device such as a seal ring (including a dust seal) or a combination seal ring is provided separately from the rolling bearing to seal the inner peripheral surface of the second connecting tube portion and the outer peripheral surface of the output shaft. In this example, the rolling bearing 96b, which is a sealing member, can prevent foreign matter from entering the inside of the gear housing 57 from between the inner peripheral surface of the second connecting tube portion 67 and the outer peripheral surface of the output shaft 73, so that the reaction force generating device 10 can be safely transported alone (as a module). This makes it possible to carry out assembly work smoothly in a variety of different factory environments.

Second Shaft Connection
A second shaft connection portion 76 is provided at the rear end of the output shaft 73, which constitutes the power connection portion 11 capable of transmitting torque to the position adjustment device 9. The second shaft connection portion 76 has a structure that is common to, for example, two or more types of reaction force generating devices that are capable of generating steering reaction forces of different magnitudes.

In this example, the second shaft connection part 76 is a male spline part, and the connection structure of the power connection part 11 is a spline structure. In particular, in this example, the second shaft connection part 76 has a semispherical male spline structure in which a plurality of male spline teeth 78 are formed in the radial direction on the outer surface of a semispherical convex part 77, as shown in FIG. 10 (A). However, as the second shaft connection part, a general male spline structure or male serration structure can also be adopted in which the outer peripheral surface of the rear end part of the output shaft is configured as a cylindrical surface, and a plurality of male spline teeth or male serration teeth are formed in the axial direction on the outer peripheral surface.

To apply a steering reaction force to the steering wheel 2 using the reaction force generating device 10, the control device 6 drives the reaction force applying motor 58 based on various signals indicating driving conditions such as steering torque, steering angle, and vehicle speed. The rotation of the reaction force applying motor 58 is transmitted to the connecting shaft 60 via a worm reduction gear 59, and is applied as a steering reaction force to the steering wheel 2 via the power connection part 11 that connects the output shaft 73 and the lower shaft 19.

In this example, the position adjustment device 9 and the reaction force generating device 10 as described above are connected at two points: the power connection part 11 and the housing connection part 12.

<Power connection part>
The power connection portion 11 directly connects, by spline engagement, a first shaft connection portion 21 provided at the front end portion of the lower shaft 19 of the steering shaft 13 constituting the position adjustment device 9 and a second shaft connection portion 76 provided at the rear end portion of the output shaft 73 constituting the reaction force generating device 10. For this reason, the power connection portion 11 has a connection structure with a spline structure.

Specifically, as shown in FIG. 10B, the hemispherical convex portion 77 constituting the second shaft connection portion 76 is inserted into the hemispherical concave portion 22 constituting the first shaft connection portion 21, and the female spline teeth 23 provided on the inner surface of the hemispherical concave portion 22 and the male spline teeth 78 provided on the outer surface of the hemispherical convex portion 77 are spline-engaged. In addition, the outer surface of the hemispherical convex portion 77 constituting the second shaft connection portion 76 is pressed backward (axially) against the inner surface of the hemispherical concave portion 22 constituting the first shaft connection portion 21. As a result, the power connection portion 11 connects the lower shaft 19 and the output shaft 73 in a torque-transmitting manner based on the meshing of the female spline teeth 23 and the male spline teeth 78, and the frictional force acting between the inner surface of the hemispherical concave portion 22 and the outer surface of the hemispherical convex portion 77. At least one of the inner surface of the hemispherical concave portion 22 and the outer surface of the hemispherical convex portion 77 can be covered with a resin coating layer or an elastic member. This suppresses rattling between the inner surface of the hemispherical recess 22 and the outer surface of the hemispherical protrusion 77, and also suppresses the generation of abnormal noise between the inner surface of the hemispherical recess 22 and the outer surface of the hemispherical protrusion 77.

In this example, in the power connection part 11, the outer surface of the hemispherical convex part 77 constituting the second shaft connection part 76 is pressed rearward against the inner surface of the hemispherical concave part 22 constituting the first shaft connection part 21. For this reason, a displacement prevention structure is separately provided to prevent the lower shaft 19 equipped with the first shaft connection part 21 from being displaced rearward.

In this example, as shown in Fig. 11, a rolling bearing 18a for rotatably supporting the lower shaft 19 with respect to the lower inner column 35 is used to prevent the lower shaft 19 from displacing rearward. Specifically, a locking groove 97 is formed in the outer circumferential surface of the lower shaft 19 at a position adjacent to the front side of the portion where the rolling bearing 18a is fitted, and a bevel-shaped retaining ring 98 having a tapered surface is engaged with the locking groove 97. Furthermore, an annular protrusion 100 that protrudes radially inward is provided on the inner circumferential surface of an inward flange-shaped annular wall portion 99 provided on the inner circumferential surface of the lower inner column 35 at a position adjacent to the rear side of the portion where the rolling bearing 18a is fitted. As a result, the rearward pressing force acting on the lower shaft 19 is supported by the lower inner column 35 via the retaining ring 98 and the rolling bearing 18a.

<Housing connection>
The housing connection portion 12 is formed by connecting a first housing connection portion 41 provided at the front end portion of the lower inner column 35 that constitutes the position adjustment device 9 and a second housing connection portion 63 provided at the rear portion of the gear housing 57 that constitutes the reaction force generating device 10 with a plurality of connection bolts 64 (see FIG. 5 ) (four in the illustrated example). Therefore, the housing connection portion 12 has a bolt connection structure.

Specifically, the first connecting plate portion 43 constituting the first housing connecting portion 41 and the second connecting plate portion 68 constituting the second housing connecting portion 63 are overlapped in the front-rear direction without any gaps, and the first connecting plate portion 43 and the second connecting plate portion 68 are joined by the connecting bolt 64 inserted from the rear side to the front side through the first through hole 44 provided in the first connecting plate portion 43 and the second through hole 69 (continuous hole 79) provided in the second connecting plate portion 68. Furthermore, in this example, when the first connecting plate portion 43 and the second connecting plate portion 68 are overlapped in the front-rear direction, the second connecting tube portion 67 is spigot-fitted to the first connecting tube portion 42. In other words, the second connecting tube portion 67 is fitted inside the first connecting tube portion 42. Also, in this example, the second connecting tube portion 67 is spigot-fitted to the first connecting tube portion 42 over the entire circumference. In this example, the housing connection part 12 connects the lower inner column 35 that constitutes the position adjustment device 9 and the gear housing 57 that constitutes the reaction force generating device 10 in the front-rear direction. Also, in this example, the housing connection part 12 is located near the power connection part 11, i.e., slightly forward of the power connection part 11.

In addition, in this example, the power connection part 11 is disposed between the housing connection part 12, which has a spigot-fit connection form, and the rolling bearing 18a in the front-rear direction. This allows the power connection part 11 to be disposed in a position that is strong against bending forces.

<How to assemble the steering unit>
The steering unit 3 of this example having the above-mentioned configuration can be assembled by the following assembly method.
First, two or more types of sub-assembled position adjustment devices are prepared, each of which has a first shaft connection portion 21 and a first housing connection portion 41 and has a different adjustable range for the steering wheel position. Also, two or more types of sub-assembled reaction force generating devices are prepared, each of which has a second shaft connection portion 76 and a second housing connection portion 63 and has a different magnitude of steering reaction force that can be generated.

Then, a position adjustment device 9 having an optimal position adjustment range for the steering wheel 2 is selected from among the multiple position adjustment devices in accordance with the vehicle in which the steering unit 3 is mounted. Also, a reaction force generating device 10 having an optimal magnitude of steering reaction force generated is selected from among the multiple reaction force generating devices in accordance with the vehicle in which the steering unit 3 is mounted.

Then, the selected position adjustment device 9 and reaction force generating device 10 are connected. Specifically, the first shaft connection portion 21 of the position adjustment device 9 and the second shaft connection portion 76 of the reaction force generating device 10 are connected by a power connection portion 11 having a spline structure, and the first housing connection portion 41 of the position adjustment device 9 and the second housing connection portion 63 of the reaction force generating device 10 are connected by a housing connection portion 12 that utilizes a bolt connection and a spigot fit.

In particular, in this example, the first shaft connection portion 21 and the second shaft connection portion 76 can be connected after the position adjustment device 9 and the reaction force generating device 10 are positioned by fitting the first connection tubular portion 42 constituting the first housing connection portion 41 and the second connection tubular portion 67 constituting the second housing connection portion 63 together. However, in this example, the first shaft connection portion 21 and the second shaft connection portion 76 can be connected by simply inserting the hemispherical convex portion 77 constituting the second shaft connection portion 76 into the inside of the hemispherical concave portion 22 constituting the first shaft connection portion 21. Therefore, the connection work between the first shaft connection portion 21 and the second shaft connection portion 76 and the connection work between the first housing connection portion 41 and the second housing connection portion 63 can be performed simultaneously. Even when the connecting operation between the first shaft connecting portion 21 and the second shaft connecting portion 76 and the connecting operation between the first housing connecting portion 41 and the second housing connecting portion 63 are performed simultaneously, if the inner surface of the hemispherical recess 22 constituting the first shaft connecting portion 21 and/or the outer surface of the hemispherical protrusion 77 constituting the second shaft connecting portion 76 are covered with a resin coating layer, fine adjustment can be performed when connecting the first shaft connecting portion 21 and the second shaft connecting portion 76. When connecting the position adjustment device 9 and the reaction force generating device 10, the axial positioning is basically performed by butting the first housing connecting portion 41 and the second housing connecting portion 63. In addition, when connecting the first housing connecting portion 41 and the second housing connecting portion 63, the second connecting tube portion 67 is spigot-fitted to the first connecting tube portion 42, so that the positioning in the diameter direction (radial direction) of the first shaft connecting portion 21 and the second shaft connecting portion 76 can be easily performed.
In this example, the steering unit 3 is assembled as described above.

According to the steering unit 3 of this embodiment as described above, the manufacturing costs can be reduced.
That is, in this example, each of the power connection part 11 and the housing connection part 12 that connect the position adjustment device 9 and the reaction force generating device 10 is not a dedicated connection structure for connecting the position adjustment device 9 and the reaction force generating device 10, but has a common connection structure with a steering unit other than the steering unit 3 of this example in which at least one of the position adjustment device 9 and the reaction force generating device 10 has a different configuration. For this reason, each of the structures of the first shaft connection part 21 and the first housing connection part 41 is a structure common to two or more types of multiple position adjustment devices that have different adjustable ranges for the position of the steering wheel, for example. Also, each of the structures of the second shaft connection part 76 and the second housing connection part 63 is a structure common to two or more types of multiple reaction force generating devices that have different magnitudes of steering reaction force that can be generated, for example.

Therefore, in this example, it is not necessary to design a dedicated steering unit 3 that has a steering wheel position adjustment range suitable for the vehicle on which it is mounted and can apply a steering reaction force of a magnitude suitable for the vehicle on which it is mounted. In this example, a position adjustment device 9 with an optimal position adjustment range is selected from a plurality of position adjustment devices, and a reaction force generating device 10 with an optimal steering reaction force magnitude is selected from a plurality of reaction force generating devices, and these position adjustment devices 9 and reaction force generating devices 10 are connected by a power connection section 11 and a housing connection section 12, thereby obtaining a steering unit 3 suitable for the vehicle on which it is mounted. In this way, in this example, the optimal combination of the position adjustment device 9 and the reaction force generating device 10 can be selected according to the vehicle, and the steering unit 3 can be assembled. Therefore, it is possible to modularize each of the position adjustment device 9 and the reaction force generating device 10, and the manufacturing cost of the steering unit 3 can be reduced.

In addition, since the structures of the first shaft connection portion 21 and the first housing connection portion 41 are common among two or more types of multiple position adjustment devices, even if a design change is required to change the position adjustment range, another position adjustment device can be easily connected to the reaction force generating device 10 instead of the position adjustment device 9. In addition, since the structures of the second shaft connection portion 76 and the second housing connection portion 63 are common among two or more types of multiple reaction force generating devices, even if a design change is required to change the magnitude of the steering reaction force generated, another reaction force generating device can be easily connected to the position adjustment device 9 instead of the reaction force generating device 10. Therefore, the labor required for design changes can be reduced, and manufacturing costs can be reduced. In addition, since the connection structures of the power connection portion 11 and the housing connection portion 12 that connect the position adjustment device 9 and the reaction force generating device 10 are common, it is possible to prevent defects from occurring in the connection portions when making design changes.

In this example, the power connection part 11 is configured by inserting the hemispherical convex part 77 constituting the second shaft connection part 76 into the hemispherical concave part 22 constituting the first shaft connection part 21, and spline-engaging the female spline teeth 23 provided on the inner surface of the hemispherical concave part 22 with the male spline teeth 78 provided on the outer surface of the hemispherical convex part 77. This makes it possible to absorb (tolerate) alignment errors between the lower shaft 19 provided with the first shaft connection part 21 and the output shaft 73 provided with the second shaft connection part 76. This makes it possible to prevent abnormal noise and a decrease in transmission efficiency due to alignment errors. In addition, even if the hemispherical concave part 22 and the hemispherical convex part 77 are twisted, torque can be efficiently transmitted between the lower shaft 19 and the output shaft 73. Furthermore, because the first shaft connection part 21 and the second shaft connection part 76 are directly connected, no joint parts are required, the axial length of the power connection part 11 can be kept short, and an increase in the number of parts can be prevented.

In addition, since the power connection part 11 and the housing connection part 12 are located close to each other, the work efficiency of connecting the position adjustment device 9 and the reaction force generating device 10 can be improved.

In addition, in this example, the outer column 34 is fitted to the lower inner column 35 to allow relative displacement in the fore-aft direction, and the upper inner column 36 is fitted to the outer column 34 to allow relative displacement in the fore-aft direction, giving the column body 25 a two-stage telescopic structure. This makes it possible to prevent the axial dimensions of the lower screw shaft 47 and the upper screw shaft 51 from becoming excessively large while ensuring a sufficient amount of telescopic movement over the entire length of the steering column 14.

In addition, the position adjustment device 9 of this example can adjust the longitudinal position of the steering wheel 2 using either the lower telescopic actuator 15 or the upper telescopic actuator 16. Therefore, even if a malfunction such as a breakdown occurs in either the lower telescopic actuator 15 or the upper telescopic actuator 16, the longitudinal position of the steering wheel 2 can be adjusted using the other actuator.

Furthermore, the position adjustment device 9 of this example can drive the lower telescopic actuator 15 and the upper telescopic actuator 16 simultaneously, so the adjustment speed of the fore-aft position of the steering wheel 2 can be improved compared to a position adjustment device equipped with only one actuator.

[Second Example of the Embodiment]
The second embodiment will be described with reference to Figures 13 to 16. In this embodiment, the same components as those in the first embodiment are given the same reference numerals as those in the first embodiment, and detailed descriptions thereof will be omitted.

In this example, the connection structure of the power connection part 11a that connects the lower shaft 19 and the output shaft 73 has been changed from that of the first embodiment. Specifically, the first shaft connection part 21a provided at the front end of the lower shaft 19 and the second shaft connection part 76a provided at the rear end of the output shaft 73 are not directly connected, but are indirectly connected via a joint member 80.

For this reason, the first shaft connection portion 21a has a male spline structure in which multiple male spline teeth 81a are formed in the axial direction on the outer peripheral surface of the front end of the lower shaft 19. In addition, an annular groove 82a that crosses the male spline teeth 81a in the circumferential direction is provided on the outer peripheral surface of the front end of the lower shaft 19.

The second shaft connection portion 76a also has a male spline structure in which multiple male spline teeth 81b are formed in the axial direction on the outer peripheral surface of the rear end of the output shaft 73. In addition, an annular groove 82b that crosses the male spline teeth 81b in the circumferential direction is provided on the outer peripheral surface of the rear end of the output shaft 73.

The joint member 80 is a cylindrical member having a generally U-shaped end face, and has a female spline portion on both axial sides of the inner peripheral surface, with female spline teeth 83a, 83b formed in the axial direction. The joint member 80 also has screw holes 84 at two positions spaced apart in the axial direction, each of which has a portion of the female spline teeth 83a, 83b cut out.

In this example, the male spline teeth 81a provided at the front end of the lower shaft 19 are spline-engaged with the female spline teeth 83a provided on the inner circumferential surface of the rear part of the joint member 80, and the male spline teeth 81b provided at the rear end of the output shaft 73 are spline-engaged with the female spline teeth 83b provided on the inner circumferential surface of the front part of the joint member 80. This connects the first shaft connection part 21a and the second shaft connection part 76a via the joint member 80 so that torque can be transmitted.

In addition, bolts 102 are screwed into each of two screw holes 84 provided in the joint member 80. This causes the middle portion of one bolt 102 to engage with the annular groove 82a provided in the outer peripheral surface of the lower shaft 19, and the middle portion of the other bolt 102 to engage with the annular groove 82b provided in the outer peripheral surface of the output shaft 73. This prevents the lower shaft 19 and the output shaft 73, which are connected via the joint member 80, from being displaced relative to each other in the front-rear direction.

In this example, the connection structure of the power connection part 11a is not a dedicated connection structure for connecting the position adjustment device 9 and the reaction force generating device 10 that constitute the steering unit 3 of this example, but is a common connection structure with a steering unit other than the steering unit 3 of this example, in which at least one of the position adjustment device 9 and the reaction force generating device 10 has a different configuration.

In this example, the connection structure of the power connection part 11a can prevent the lower shaft 19 from being displaced in the fore-and-aft direction. This makes it possible to omit the displacement prevention structure using a rolling bearing as in the first example of the embodiment described above. In addition, when assembling the steering unit 3 of this example, the first housing connection part 41 can be connected to the second housing connection part 63 after the first shaft connection part 21a and the second shaft connection part 76a are connected via the joint member 80.

As a modification of this example, each of the first shaft connecting portion and the second shaft connecting portion can be a male serration portion instead of a male spline portion. In this case, a female serration portion is provided on the inner peripheral surface of the joint member instead of a female spline portion. Also, as a modification of this example, a Cardan joint can be used. In this case, alignment errors between the lower shaft and the output shaft can be absorbed.
The other configurations and effects are the same as those of the first embodiment.

[Third Example of the Embodiment]
The third example of the embodiment will be described with reference to Figures 17 to 20. In this example, components similar to those in the first example of the embodiment are given the same reference numerals as in the first example of the embodiment, and detailed descriptions thereof will be omitted.

In this example, the connection structure of the power connection part 11b that connects the lower shaft 19 and the output shaft 73 has been changed from that of the first embodiment. Specifically, the first shaft connection part 21b provided at the front end of the lower shaft 19 and the second shaft connection part 76b provided at the rear end of the output shaft 73 are not directly connected, but are indirectly connected via a shaft coupling 85.

In this example, the shaft-shaped portion having a cylindrical outer peripheral surface provided at the front end of the lower shaft 19 serves as the first shaft connection portion 21b. Note that a notch or key groove may be formed in a portion of the outer peripheral surface of the shaft-shaped portion in the circumferential direction to prevent rotation.

The shaft-shaped portion having a cylindrical outer circumferential surface provided at the rear end of the output shaft 73 is the second shaft connection portion 76b. The second shaft connection portion 76b can also have a notch or key groove formed in a circumferential portion of the outer circumferential surface of the shaft-shaped portion to prevent rotation.

The shaft coupling 85 includes a first transmission member 86 that is connected to the first shaft connection portion 21b in a manner that prevents relative rotation, a second transmission member 87 that is connected to the second shaft connection portion 76b in a manner that prevents relative rotation, and an intermediate member 88 that is disposed between the first transmission member 86 and the second transmission member 87 and transmits torque between the first transmission member 86 and the second transmission member 87.

The first transmission member 86 has an insertion hole 89a penetrating the axial direction in the center, and has notches 103a extending radially at two circumferential positions. The first transmission member 86 also has protrusions 90a protruding in the axial direction at multiple circumferential positions. To connect the first transmission member 86 to the first shaft connection part 21b, the first shaft connection part 21b is inserted into the insertion hole 89a, and a screw member (not shown) arranged in a circumferential part of the first transmission member 86 is tightened using a tool (not shown). This reduces the circumferential width of the notch 103a and the inner diameter of the insertion hole 89a, thereby connecting the first transmission member 86 to the first shaft connection part 21b.

The second transmission member 87 has an insertion hole 89b penetrating in the axial direction in the center, and has notches 103b extending in the radial direction at two circumferential positions. The second transmission member 87 also has protrusions 90b protruding in the axial direction at multiple circumferential positions. To connect the second transmission member 87 to the second shaft connection part 76b, the second shaft connection part 76b is inserted into the insertion hole 89b, and a screw member (not shown) arranged in a circumferential part of the second transmission member 87 is tightened using a tool (not shown). This reduces the circumferential width of the notch 103b and the inner diameter of the insertion hole 89b, thereby connecting the second transmission member 87 to the second shaft connection part 76b.

The intermediate member 88 is made of, for example, an elastic material and is configured in a circular ring shape. The intermediate member 88 has circular ring portions 104a, 104b on both axial sides. The circular ring portion 104a has first engagement holes (not shown) at multiple locations in the circumferential direction into which the protrusions 90a provided on the first transmission member 86 can be inserted. The circular ring portion 104b has second engagement holes (not shown) at multiple locations in the circumferential direction into which the protrusions 90b provided on the second transmission member 87 can be inserted.

In this example, the connection structure of the power connection part 11b is not a dedicated connection structure for connecting the position adjustment device 9 and the reaction force generating device 10 that constitute the steering unit 3 of this example, but is a common connection structure with a steering unit other than the steering unit 3 of this example, in which at least one of the position adjustment device 9 and the reaction force generating device 10 has a different configuration.

In this example, the structure of each of the first shaft connecting portion 21b and the second shaft connecting portion 76b can be simplified, which reduces the processing cost of the first shaft connecting portion 21b and the second shaft connecting portion 76b. In addition, since the first shaft connecting portion 21b and the second shaft connecting portion 76b are connected via the shaft coupling 85, alignment errors can be absorbed.
The other configurations and effects are the same as those of the first embodiment.

[Fourth Example of the Embodiment]
The fourth embodiment will be described with reference to Figures 21 to 23. In this embodiment, components similar to those in the first embodiment are given the same reference numerals as in the first embodiment, and detailed descriptions thereof will be omitted.

In this example, the connection structure of the power connection part 11c that connects the lower shaft 19 and the output shaft 73 has been changed from that of the first embodiment. Specifically, the first shaft connection part 21c provided at the front end of the lower shaft 19 and the second shaft connection part 76c provided at the rear end of the output shaft 73 are not directly connected, but are indirectly connected via an elastic cylindrical member 91.

In this example, the first shaft connection portion 21c has a gear structure in which a male engagement portion 105a is formed in the circumferential direction on the outer peripheral surface of the front end portion of the lower shaft 19.

The second shaft connection portion 76c also has a gear structure in which a male engagement portion 105b is formed around the outer circumferential surface of the rear end of the output shaft 73.

The elastic tubular member 91 is made of an elastic material such as rubber and is cylindrical. The elastic tubular member 91 has a female engagement portion 106 in the circumferential direction over the entire axial range of its inner surface.

In this example, the first shaft connection portion 21c provided at the front end of the lower shaft 19 is press-fitted into the rear side of the elastic tubular member 91, engaging the male engagement portion 105a and the female engagement portion 106 so that they cannot rotate relative to each other. Also, the second shaft connection portion 76c provided at the rear end of the output shaft 73 is press-fitted into the front side of the elastic tubular member 91, engaging the male engagement portion 105b and the female engagement portion 106 so that they cannot rotate relative to each other. This connects the first shaft connection portion 21c and the second shaft connection portion 76c via the elastic tubular member 91 so that torque can be transmitted.

In this example, the connection structure of the power connection part 11c is not a dedicated connection structure for connecting the position adjustment device 9 and the reaction force generating device 10 that constitute the steering unit 3 of this example, but is a common connection structure with a steering unit other than the steering unit 3 of this example, in which at least one of the position adjustment device 9 and the reaction force generating device 10 has a different configuration.

In this example, the first shaft connecting portion 21c and the second shaft connecting portion 76c are connected via the elastic tubular member 91 made of an elastic material, so that alignment errors can be absorbed.
The other configurations and effects are the same as those of the first embodiment.

[Fifth Example of the Embodiment]
A fifth example of the embodiment will be described with reference to Fig. 24. In this example, components similar to those in the first example of the embodiment are given the same reference numerals as in the first example of the embodiment, and detailed description thereof will be omitted.

In this example, the outer diameter of the axially intermediate portion of the output shaft 73a adjacent to (connected to) the second shaft connection portion 76 is smaller than the outer diameter of the second shaft connection portion 76 (hemispherical convex portion 77). In other words, the output shaft 73a has a constricted portion adjacent to the front side of the second shaft connection portion 76, the constricted portion having a smaller diameter than the second shaft connection portion 76. For this reason, in this example, the rear portion of the output shaft 73a is shaped approximately mushroom-like.

In the present embodiment as described above, even if an alignment error occurs in which the central axis of the output shaft 73a does not coincide with the central axis of the lower shaft 19, as shown in Fig. 24C, the front end face of the lower shaft 19 is unlikely to interfere with the outer circumferential surface of the output shaft 73a. Therefore, the alignment error can be sufficiently absorbed.
The other configurations and effects are the same as those of the first embodiment.

[Sixth Example of the Embodiment]
A sixth example of the embodiment will be described with reference to Fig. 25. In this example, components similar to those in the first example of the embodiment are given the same reference numerals as those in the first example of the embodiment, and detailed descriptions thereof will be omitted.

In this example, the connection structure of the housing connection portion 12a that connects the lower inner column 35 and the gear housing 57 has been changed from that of the first embodiment. Specifically, the inner circumferential surface shape of the first connection tube portion 42a that constitutes the first housing connection portion 41a and the outer circumferential surface shape of the second connection tube portion 67a that constitutes the second housing connection portion 63a have been changed from that of the first embodiment.

The first connecting tube portion 42a has a first tapered portion 92 on the front side of the inner circumferential surface, the inner diameter of which decreases from the front side to the rear side. The second connecting tube portion 67a has a second tapered portion 93 on the front side of the outer circumferential surface, the outer diameter of which decreases from the front side to the rear side.

When the first housing connection portion 41a and the second housing connection portion 63a are connected, the first tapered portion 92 on the inner peripheral surface of the first connection tube portion 42a is radially overlapped with the second tapered portion 93 on the outer peripheral surface of the second connection tube portion 67a.

In this example, the connection structure of the housing connection part 12a is not a dedicated connection structure for connecting the position adjustment device 9 and the reaction force generating device 10 that constitute the steering unit 3 of this example, but is a common connection structure with a steering unit other than the steering unit 3 of this example, in which at least one of the position adjustment device 9 and the reaction force generating device 10 has a different configuration.

In this example, the first connecting tubular portion 42a has a first tapered portion 92 on the front side of its inner circumferential surface, and the second connecting tubular portion 67a has a second tapered portion 93 on the front side of its outer circumferential surface, so that the second connecting tubular portion 67a can be spigot-fitted into the first connecting tubular portion 42a by utilizing the first tapered portion 92 and the second tapered portion 93. This makes it even easier to position the first shaft connecting portion 21 and the second shaft connecting portion 76 in the diameter direction (radial direction).
The other configurations and effects are the same as those of the first embodiment.

[Seventh Example of the Embodiment]
The seventh example of the embodiment will be described with reference to Figures 26 to 28. In this example, components similar to those in the first example of the embodiment are given the same reference numerals as in the first example of the embodiment, and detailed descriptions thereof will be omitted.

In this example, the position adjustment device 9a that constitutes the steering unit 3 is a manual position adjustment device, rather than an electric position adjustment device as in the structure of the first example of the embodiment. The position adjustment device 9a is capable of adjusting the front-rear and up-down positions of the steering wheel 2 (see FIG. 1), and supports the steering shaft 108 rotatably inside the steering column 107 via a pair of rolling bearings 18d, 18e.

To allow the adjustment of the fore-aft position of the steering wheel 2, the steering column 107 is configured so that the outer column 109 arranged on the lower side is fitted to the inner column 110 arranged on the upper side to allow relative displacement in the fore-aft direction, making the overall length extendable. The steering shaft 108 is configured so that the outer shaft 112 arranged on the upper side is fitted to the inner shaft 111 arranged on the lower side to allow torque transmission and relative displacement in the fore-aft direction, making the overall length extendable. In this example, a rolling bearing 18d is arranged between the outer column 109 and the inner shaft 111, and a rolling bearing 18e is arranged between the inner column 110 and the outer shaft 112.

In addition, in order to enable adjustment of the vertical position of the steering wheel 2, a gear housing 57a (described later) is pivoted relative to the vehicle body by a tilt shaft (not shown) arranged in the width direction, and the rear portion of the outer column 109 is supported relative to a support bracket 113 fixed to the vehicle body so as to allow vertical displacement.
To adjust the position of the steering wheel 2, an adjustment lever (not shown) is operated to reduce the tightening force of the support bracket 113 on the outer column 109, and the position of the steering wheel 2 is manually adjusted.

In this example, the first housing connection portion 41b is integrally provided at the front end of the outer column 109 that constitutes the position adjustment device 9a having the configuration described above.

The first housing connection portion 41b has a structure common to two or more position adjustment devices having different ranges of adjustable position of the steering wheel. The first housing connection portion 41b has a first connection flange portion 115 in the form of an outward flange, which is bent radially outward from the front end of the cylindrical portion 114 constituting the outer column 109. A first through hole (not shown) penetrating in the front-rear direction is provided at multiple circumferential positions (three positions in the illustrated example) of the first connection flange portion 115. In addition, in this example, a seal ring 119, which is a sealing member, is provided between the inner peripheral surface of the first housing connection portion 41b (the front end portion of the outer column 109) and the outer peripheral surface of the output shaft 73 constituting the reaction force generating device 10a. This seals the gap between the inner peripheral surface of the first housing connection portion 41b and the outer peripheral surface of the output shaft 73, preventing foreign matter such as grease from entering the inside of the gear housing 57a constituting the reaction force generating device 10a.

In this example, the gear housing 57a that constitutes the reaction force generating device 10a that connects to the front side of the position adjustment device 9a is composed of a lower housing 61 and a second housing connection portion 63b.

The second housing connection portion 63b has a structure common to two or more types of reaction force generating devices that have different steering reaction force magnitudes. The second housing connection portion 63b is annular and fixed to the rear side of the worm wheel accommodating portion 66 that constitutes the lower housing 61. The second housing connection portion 63b has a fitting tube portion 116 that is fitted into the worm wheel accommodating portion 66, an outward flange-shaped second connection flange portion 117 that is bent radially outward from the rear end of the fitting tube portion 116, and a plurality of partially cylindrical protrusions 118 that protrude axially from the inner peripheral edge of the second connection flange portion 117. The second connection flange portion 117 is provided with second through holes (not shown) that penetrate in the front-rear direction at multiple circumferential positions (three positions in the illustrated example).

The housing connection part 12b in this example is formed by connecting the first housing connection part 41b provided at the front end part of the outer column 109 of the position adjustment device 9a to the second housing connection part 63b provided at the rear part of the gear housing 57a constituting the reaction force generating device 10a with multiple connection bolts 64a. Therefore, the housing connection part 12b has a bolt connection structure.

Specifically, the front end surface of the first connecting flange portion 115 constituting the first housing connecting portion 41b and the rear end surface of the second connecting flange portion 117 constituting the second housing connecting portion 63b are overlapped with no gap in the front-rear direction, and the first connecting flange portion 115 and the second connecting flange portion 117 are joined by the connecting bolts 64a inserted from the rear to the front through the first through holes provided in the first connecting flange portion 115 and the second through holes provided in the second connecting flange portion 117. Furthermore, in this example, when the first connecting flange portion 115 and the second connecting flange portion 117 are overlapped in the front-rear direction, the multiple protrusions 118 constituting the second housing connecting portion 63b are spigot-fitted into the first connecting flange portion 115. In this example, the outer column 109 constituting the position adjustment device 9a and the gear housing 57a constituting the reaction force generating device 10a are connected in the front-rear direction by such a housing connecting portion 12b. In this example, the housing connection portion 12b having a spigot-fit connection is disposed radially outside the torque sensor 75 disposed around the output shaft 73. Therefore, the housing connection portion 12b is disposed at a position radially overlapping with the torque sensor 75 in the radial direction of the output shaft 73.

In the present embodiment as described above, the first housing connection portion 41b is integrally formed with the cylindrical portion 114 constituting the outer column 109. Therefore, compared to the structures of the first and sixth embodiments, the number of parts can be reduced, and the number of assembly steps can be reduced. In addition, since the protrusion portion 118 constituting the second housing connection portion 63b is spigot-fitted into the first connection flange portion 115 , the workability of connecting the first connection flange portion 115 and the second connection flange portion 117 with the connection bolt 64a can be improved. Furthermore, since the housing connection portion 12b is disposed at a position radially overlapping with the torque sensor 75 in the radial direction of the output shaft 73, the inclination of the output shaft 73 can be suppressed, and the detection accuracy of the torque sensor 75 can be improved.
The other configurations and effects are the same as those of the first embodiment.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and can be modified as appropriate without departing from the technical concept of the invention. Furthermore, the structures of each example of the embodiment can be combined as appropriate as long as no contradiction occurs.

For example, when implementing the present invention, the respective structures of the power connection part and the housing connection part are not limited to the structures described in the embodiment, and various conventionally known structures can be adopted. Furthermore, the structures of the first shaft connection part and the second shaft connection part constituting the power connection part, and the structures of the first housing connection part and the second housing connection part constituting the housing connection part are not limited to the structures described in the embodiment, and various conventionally known structures can be adopted.

When selecting a position adjustment device from among a plurality of position adjustment devices, the plurality of position adjustment devices that are candidates for selection are not limited to position adjustment devices with different position adjustment ranges, but can include position adjustment devices with different configurations of other parts. Also, when selecting a reaction force generating device from among a plurality of reaction force generating devices, the plurality of reaction force generating devices that are candidates for selection are not limited to reaction force generating devices with different magnitudes of steering reaction force that can be generated, but can include reaction force generating devices with different configurations of other parts.

In addition, when implementing the present invention, the position adjustment device to be combined with the reaction force generating device is not limited to an electrically operated position adjustment device as shown in the first embodiment, but a manual position adjustment device as shown in the seventh embodiment can also be used.

The technical concept of the present invention is not limited to steer-by-wire steering devices in which a steering unit to which a steering wheel is attached and a steering unit for applying a steering angle to the steered wheels are electrically connected, not mechanically, but can also be applied to general electric power steering devices in which a steering unit and a steering unit are mechanically connected. In this case, the reaction force generating device is replaced with a steering force assist device for applying an assist torque to the steering shaft according to the direction and magnitude of the torque applied to the steering shaft.

REFERENCE SIGNS LIST 1 steering device 2 steering wheel 3 steering unit 4 steering wheel 5 steering unit 6 control device 7 steering actuator 8 tie rod 9, 9a position adjustment device 10, 10a reaction force generating device 11, 11a, 11b, 11c power connection portion 12, 12a, 12b housing connection portion 13 steering shaft 14 steering column 15 lower telescopic actuator 16 upper telescopic actuator 17 tilt actuator 18a to 18e rolling bearing 19 lower shaft 20 upper shaft 21, 21a, 21b, 21c first shaft connection portion 22 hemispherical recess 23 female spline teeth 24 bracket 25 column body 26 fixed bracket 27 displacement bracket 28 fixed plate portion 29 fixed side support frame 30 mounting bolt 31 Displacement plate portion 32 Displacement side support frame 33 Support wall portion 34 Outer column 35 Lower side inner column 36 Upper side inner column 37 Slit 38 Screw hole 39 Screw plug 40 Cylindrical portion 41, 41a, 41b First housing connection portion 42, 42a First connection cylinder portion 43 First connection plate portion 44 First through hole 45 Lower side telescopic motor 46 Lower side feed screw device 47 Lower side screw shaft 48 Lower side nut 49 Upper side telescopic motor 50 Upper side feed screw device 51 Upper side screw shaft 52 Upper side nut 53 Connector member 54 Pivot bolt 55 Tilt motor 56 Tilt feed screw device 57, 57a Gear housing 58 Reaction force applying motor 59 Worm reducer 60 Connecting shaft 61 [0033] Lower housing 62 Upper housing 63, 63a, 63b Second housing connection portion 64, 64a Connection bolt 65 Worm accommodating portion 66 Worm wheel accommodating portion 67, 67a Second connection cylinder portion 68 Second connection plate portion 69 Second through hole 70 Worm 71 Worm wheel 72 Input shaft 73, 73a Output shaft 74 Torsion bar 75 Torque sensor 76, 76a, 76b, 76c Second shaft connection portion 77 Hemispherical convex portion 78 Male spline teeth 79 Continuous hole 80 Joint member 81a, 81b Male spline teeth 82a, 82b Annular groove 83a, 83b Female spline teeth 84 Screw hole 85 Shaft coupling 86 First transmission member 87 Second transmission member 88 Intermediate member Reference Signs List 89a, 89b Insertion hole 90a, 90b Projection portion 91 Elastic tubular member 92 First tapered portion 93 Second tapered portion 94 Linear guide 95 Bolt 96a, 96b, 96c Rolling bearing 97 Locking groove 98 Retaining ring 99 Annular wall portion 100 Annular projection portion 101 Bolt 102 Bolt 103a, 103b Notch 104a, 104b Circular ring portion 105a, 105b Male engaging portion 106 Female engaging portion 107 Steering column 108 Steering shaft 109 Outer column 110 Inner column 111 Inner shaft 112 Outer shaft 113 Support bracket 114 Cylindrical portion 115 First connecting flange portion 116 Fitting tubular portion 117 Second connecting flange portion 118 Protrusion portion 119 Seal ring

Claims (6)

a position adjustment device for adjusting a position of a steering wheel, the position adjustment device having a first shaft connection portion and a first housing connection portion,
a reaction force generating device for applying a steering reaction force to the steering wheel, the reaction force generating device having a second shaft connection portion connectable to the first shaft connection portion and a second housing connection portion connectable to the first housing connection portion;
A method for assembling a steer-by-wire steering unit comprising:
As the position adjustment device, one selected from two or more types of a plurality of position adjustment devices each having the first shaft connection portion and the first housing connection portion is used, and/or as the reaction force generating device, one selected from two or more types of a plurality of reaction force generating devices each having the second shaft connection portion and the second housing connection portion is used.
A method for assembling a steering unit for steer-by-wire. A method for assembling a steer-by-wire steering unit as described in claim 1, in which the first housing connection portion and the second housing connection portion are connected by a spigot fitting. a position adjustment device for adjusting a position of a steering wheel, the position adjustment device having a first shaft connection portion and a first housing connection portion,
a reaction force generating device for applying a steering reaction force to the steering wheel, the reaction force generating device having a second shaft connection portion connectable to the first shaft connection portion and a second housing connection portion connectable to the first housing connection portion;
a power connection portion connecting the first shaft connection portion and the second shaft connection portion;
a housing connection portion that connects the first housing connection portion and the second housing connection portion,
Each of the power connection unit and the housing connection unit has a connection structure common to another steer-by-wire steering unit in which at least one of the position adjustment device and the reaction force generating device has a different configuration.
Steer-by-wire steering unit. the position adjustment device includes a steering shaft having the first shaft connection portion at a front end thereof, a steering column having the first housing connection portion at a front end thereof, and a rolling bearing for rotatably supporting the steering shaft inside the steering column,
the first housing connection portion and the second housing connection portion are connected by spigot fitting,
The power connection portion is disposed between the housing connection portion and the rolling bearing in the front-rear direction.
A steer-by-wire steering unit according to claim 3. the reaction force generating device includes an output shaft having the second shaft connection portion at a rear end thereof, and a torque sensor disposed around the output shaft;
the first housing connection portion and the second housing connection portion are connected by spigot fitting,
The housing connection portion is disposed at a position overlapping with the torque sensor in a radial direction of the output shaft.
A steer-by-wire steering unit according to any one of claims 3 to 4. a position adjustment device for adjusting a position of a steering wheel, the position adjustment device having a first housing connection portion;
a reaction force generating device for applying a steering reaction force to the steering wheel, the reaction force generating device having a second housing connecting portion connectable to the first housing connecting portion;
a housing connection portion that connects the first housing connection portion and the second housing connection portion,
the housing connection portion has a common connection structure with another steer-by-wire steering unit in which at least one of the position adjustment device and the reaction force generating device has a different configuration,
the position adjustment device includes a steering shaft and a steering column having the first housing connection portion,
the reaction force generating device includes an output shaft connected to the steering shaft and a gear housing having the second housing connection portion,
the second housing connection portion has a cylindrical second connection tube portion that is connectable to the first housing connection portion by spigot fitting,
A gap between an inner peripheral surface of the second connecting cylindrical portion and an outer peripheral surface of the output shaft is sealed.
Steer-by-wire steering unit.

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