JP2007320452A - Steering device for vehicle wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem arising when vehicle wheel(s) is turned, that turning the wheel with a large steering angle can not be conducted resulting from interference of the wheel with a member positioned between the wheel and the body such as an arm of a suspension device. <P>SOLUTION: A support 8 is coupled with a hub 4 which bears the wheel 1 rotatably, and is coupled with the body by link structures 9 and 15, and the wheel 1 is steered while the link structures 9 and 15 rotate round the coupling points 11 and 12. When steering is conducted, the link structures 9 and 15 work so that the grounding point of the wheel 1 draws part of an ellipse whose long axis stretches in the vehicle fore-and-aft direction and short axis does in the direction across the vehicle width. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wheel steering device that is required for turning a vehicle, and particularly to a technique for steering a wheel at a large steering angle.

  Generally, a wheel steering device that turns a wheel based on a steering operation by a driver can turn a hub member that rotatably supports the wheel to a free end of an arm on the vehicle body side when viewed from the hub member. Connect to Further, a control rod extending in the vehicle width direction is connected to the hub member. Then, the control rod is moved forward and backward in the vehicle width direction to rotate the hub member around the connecting point and steer the wheel.

However, in the generally well-known turning device as described above, when the wheel rotates in an arc around the connection point (kingpin shaft), if the turning angle of the wheel is increased, it interferes with the arm. The rudder angle cannot be increased.
Therefore, as the wheel turning device capable of turning at a large turning angle that allows the maximum turning angle to be 180 degrees or more, the devices described in Patent Document 1 and Patent Document 2 are conventionally known. .
An outline of the vehicle suspension device described in Patent Literature 1 and Patent Literature 2 will be described using the terms of Patent Literature 2. The base ends (vehicle width outer ends) of the auxiliary upper arm and the lower arm that can swing in the vertical direction of the vehicle are attached to the vehicle body. An arc-shaped arm having an arc shape that is slightly larger than the outer diameter of the wheel is connected to the free ends (vehicle width outer ends) of the auxiliary upper arm and the lower arm. An upper end of the king pin is rotatably connected to the central top portion of the arc-shaped arm via a wheel steering mechanism. A wheel is rotatably attached to the king pin lower end of the king pin extending in the vehicle vertical direction, and the wheel is accommodated in the inner periphery of the arc-shaped arm. Thereby, these arc-shaped arms, kingpins, and wheels are suspended under the spring.
JP-A-5-124535 JP-A-6-64556

However, the conventional vehicle suspension system has the following problems.
That is, the arc arm is a member larger than the outer diameter of the wheel, and the kingpin arm is a member longer than the radius of the wheel. Since the wheels are attached via these large members, the unsprung mass increases. In addition, the weight of the auxiliary upper arm and lower arm for suspending these large members cannot be avoided. In particular, in the configuration in which the wheel drive motor is installed in the air space in the road wheel, the unsprung mass becomes larger. If it does so, it will become difficult to attenuate the vibration of a vehicle up-down direction at the time of bounding and rebounding of a wheel, and riding comfort performance will deteriorate.

  In view of the above circumstances, the present invention proposes a wheel steering device that can suspend a wheel so as to be steerable at a large turning angle without increasing unsprung mass.

For this purpose, the wheel steering device according to the invention is as described in claim 1,
In a wheel steering device for connecting a hub member rotatably supporting a wheel to a vehicle body side by a link structure, and turning the wheel by turning the link structure around a connection point,
With the link structure, when turning, the ground contact point of the wheel is configured to draw a part of an ellipse having a long axis in the vehicle longitudinal direction and a short axis in the vehicle width direction. is there.

According to such a configuration of the present invention, the structure where the ground contact center of the wheel draws a part of an ellipse having a long axis in the vehicle front-rear direction and a short axis in the vehicle width direction when turning by the link structure. Because
As the turning angle of the wheel is increased, the position of the wheel is greatly separated from the position in the non-steered state in the vehicle front-rear direction. Therefore, it is possible to avoid the wheel being steered from interfering with the arm, and the wheel can be steered without excessively unsprung mass as in the conventional case.
In addition, since the device of the present invention is in a link structure that connects a hub member and an arm, arm members such as an upper arm and a lower arm in a general steering apparatus can be used. No need for upper arm or lower arm. Therefore, an increase in unsprung weight can be avoided to ensure riding comfort performance.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 is a plan view showing a wheel turning device according to an embodiment of the present invention, and shows a straight traveling state in which the left wheel is not turning. FIG. 2 is a front view of the embodiment, showing a straight traveling state in which the wheels are not steered.
The wheel 1 attached to the front left side of the vehicle body includes a tire 2 on the outer periphery and a road wheel 3 on the center. The wheel 1 is rotatably attached to the hub member 4. FIG. 1 shows surfaces of the wheel 1 and the hub member 4 cut by a horizontal plane including the rotation axis of the wheel 1. FIG. 2 shows a surface of the wheel 1 cut by a vertical surface including the rotation axis of the wheel 1.

As shown in FIG. 2, a lower end of a strut 5 extending in a substantially vertical direction is attached to the upper part of the hub member 4. The upper end of the strut 5 is attached to a vehicle body (not shown). An elastic member is inserted in the upper and lower mounting portions, and bending of the mounting portion is allowed.
In FIG. 2, a link structure to be described later is arranged in the extending direction of the strut 5 indicated by a one-dot chain line. Thereby, in the area | region where the turning angle of a wheel is not large, the hub member 4 and the wheel 1 steer centering on the extension direction of the strut 5 as a rotation center.

  The strut 5 includes a suspension spring 6 at an upper portion thereof and a shock absorber 7 at a lower portion thereof. The suspension spring 6 reduces the impact input to the wheel 1 from the ground contact surface. The shock absorber 7 dampens vertical vibration accompanying bounce and rebound.

A plate-like support portion 8 is attached to the lower portion of the hub member 4. The support portion 8 is integrally coupled to the hub member 4 and is located in the inner space region of the road wheel 3.
The support portion 8 extends in the vehicle front-rear direction as shown in FIG. 1 in a non-steered state, and its front end portion is rotatably connected to one end of the first link 9. Further, the rear end portion is rotatably connected to one end of the second link 15.

  The other end of the first link 9 is rotatably connected to an outer end in the vehicle width direction of an arm 10 (also referred to as a lower arm) that is a member on the vehicle body side. The other end of the second link 15 is also rotatably connected to the outer end of the arm 10 in the vehicle width direction. In this way, the hub member 4 and the arm 10 are mechanically connected by the link structure including the first link 9 and the second link 15. An inner end in the vehicle width direction (not shown) of the arm 10 is pivotally supported so as to be swingable in the vertical direction. The inner end of the vehicle width direction is the base end, and the outer end in the vehicle width direction is the free end. Enable bound and rebound.

The first link 9 has a plate shape with a horizontal plane, a third connection point 13 that is connected to the front end of the support portion 8 at one end thereof, and a first connection that is connected to the arm 10 on the vehicle body side at the other end. Point 11 has a rotating shaft extending in the vehicle vertical direction. The second link 15 is longer than the first link 9 and has a horizontal plate shape. The second link 15 is connected to the rear end of the support portion 8 at one end of the second link 15 and the vehicle body at the other end. The second connection point 12 connected to the arm 10 on the side has a rotating shaft extending in the vehicle vertical direction.
Therefore, the hub member 4 is rotatable with respect to the first link 9 and the second link 15 on a substantially horizontal plane around a rotation axis extending in the vehicle vertical direction.

  The positional relationship between the first connection point 11 and the second connection point 13 provided on the first link 9 is located in the vehicle width direction as shown in FIG. Further, the positional relationship between the second connection point 12 and the fourth connection point 14 provided on the second link 15 is approximately in the vehicle front-rear direction as shown in FIG. The second connection point 12 in the front is located slightly inward of the vehicle width from the fourth connection point 14 in the rear of the vehicle.

  In the non-steering state, as shown in FIG. 1, the first connection point 11 and the second connection point 13 are located on the rotation axis of the wheel 1 extending in the vehicle width direction, and accordingly, the first link 9. Is also located on the rotation axis of the wheel 1. Further, the central axis of the arm 10 is also located on the rotation axis of the wheel 1.

An arm portion 19 is coupled to the vehicle width inner end of the first link 9. One end of a control rod 16 extending in the vehicle width direction is connected to the tip of the arm portion 19.
The other end of the control rod 16 is connected to the rack member 17 of the steering device operated by the driver. When the driver operates the steering device, the rack member 17 moves back and forth in the direction of the vehicle width in the direction of the arrow in FIG. 1, and the control rod 16 also moves back and forth in the direction of the vehicle width. Turn to. Thereby, the hub member 4 and the wheel 1 are steered. This state will be described later with reference to FIGS.

  FIG. 3 is a side view of the embodiment shown in FIGS. 1 and 2 as viewed from the inside of the vehicle width. Here, the arm 10 and the control rod 16 are represented by a cross section perpendicular to the vehicle width direction.

  The embodiment shown in FIGS. 1 to 3 described above includes the strut 5, but in addition to the link structure described above instead of the strut 5, as in the other embodiments shown in the front view of FIG. 4. Further, a double wishbone type in which the above link structure is provided on the upper part and the lower part of the hub member 4 may be provided. In the case of the embodiment shown in FIG. 4, the suspension spring 6 and the shock absorber 7 are crossed with the upper arm 10, and the lower end of the shock absorber 7 is connected to the lower arm 10.

Further, an in-wheel type motor 18 that drives the wheel 1 may be provided as the hub member.
The motor 18 includes an output shaft (not shown) coaxially with the rotating shaft of the wheel 1. This output shaft is coupled to the wheel 1. The outer diameter of the motor 18 having a substantially cylindrical shape is smaller than the inner diameter of the hollow cylindrical load wheel 3, and half of the motor unit 5 is disposed in the inner space of the load wheel 3 as shown in FIG. 3. Thus, a so-called in-wheel motor structure is obtained. When the motor unit 5 is powered, the output shaft of the motor unit 5 rotates and drives the wheels 1.

  FIG. 5 is a plan view of the embodiment shown in FIG. 4 and FIG. 4 as viewed from above the vehicle. For easy understanding, FIG. 5 omits the lower arm 10 and the link structure connected thereto, and shows the upper arm 10 and the link structure connected thereto.

  In addition, although not shown about the wheel attached to the vehicle body right side, the steering apparatus of a right wheel is also comprised symmetrically with the steering apparatus of the left wheel 1 mentioned above.

  Next, how to steer each embodiment described above will be described with reference to FIGS.

FIG. 6 is a plan view schematically showing how the steering device of this embodiment turns. In FIG. 6, the positions denoted by the numerical symbols 8, 9 and 15 are the positions in the non-steering state. Here, the first link 9 extends in the vehicle width direction, and the support portion 8 of the hub member 4 extends in the vehicle front-rear direction. In addition, the ground contact point 1c where the wheel 1 contacts the road surface is on the rotation axis “le” of the wheel 1 in a non-steered state, that is, on the central axis of the first link 9 indicated by a one-dot chain line. In practice, since the tire 2 is compressed and deformed and contacts the road surface in a plane, the contact point 1c is also the center of the contact surface (also referred to as a contact center 1c).
The position of the first link 9 in the non-steering state is indicated by a symbol “a”.

  When the wheel 1 is steered as a turning inner wheel by moving the control rod 16 back and forth and turning the first link 9 around the first connection point 11, the position of the first link 9 is changed from the reference character a. , Ha, D, and Ho change continuously. Further, when the wheel 1 is steered as a turning outer wheel, it continuously changes from symbol A to G.

In FIG. 6, paying attention to the first link 9, the vehicle width inner end (first connection point 11) of the first link 9 is rotatably supported by the arm 10, so the vehicle width outer end of the first link 9. (Third connection point 13) draws a circular locus “H”.
When attention is paid to the second link 15, the vehicle front end of the second link 15 (the second connection point 12 that is also the inner end of the vehicle width) is rotatably supported by the arm 10. (Fourth connection point 14 which is also the outer end of the vehicle width) draws a circular locus “Li”.

And since the 3rd connection point 13 and the 4th connection point 14 which are on the locus | trajectory h of these circular arcs and ri are also the both ends of the support part 8, the support part 8 is also continuous according to position it. To change. Accordingly, both the hub member 4 coupled to the support portion 8 and the wheel 1 pivotally supported by the hub member 4 are continuously changed according to the position it, and the ground contact center 1c is shown in FIG. Draw a trajectory like a dotted line.
As shown in FIG. 6, this trajectory is a part of an ellipse having a long axis in the longitudinal direction of the vehicle, passes most outside the vehicle width in the non-steering state, and increases as the turning angle increases. Head inward.

In the present embodiment, since the ground contact point of the wheel 1 is a part of an ellipse that is long in the vehicle front-rear direction as indicated by the trajectory, the following effects can be obtained.
In other words, the conventional steered wheels are steered while the arcing center is drawn around the kingpin axis so that the steered wheels interfere with suspension components such as the lower arm when the steered angle is increased. Therefore, the turning angle cannot be increased.
However, in the present embodiment, the ground contact center 1c is not an arc but a long ellipse is drawn in the vehicle front-rear direction by turning, so that the turning angle of the wheel 1 increases as the turning angle increases from position A to B, C, D, E. The amount of movement in the vehicle front-rear direction can be increased, and the vehicle can be separated from the rotation axis “le” of the wheel 1 and the arm 10 shown in FIG. 6. Therefore, the wheel 1 does not interfere with the arm 10 and the wheel 1 can be steered greatly.

  The major and minor axes of the ellipse are adjusted by adjusting the length of the support 8, the length of the first link 9, the length of the second link 15, and the relative relationship between the first connection point 11 and the second connection point 12. The positional relationship may be set as appropriate.

In FIG. 6, since the positions of the second links 15 corresponding to the positions B, C, D, and E of the first link 9 are omitted, the steered state of this embodiment corresponding to the positions C and E Is more specifically shown in FIG. 7A shows a steered state corresponding to position A, FIG. 7B shows a steered state corresponding to position C, and FIG. 7C shows a steered state corresponding to position e. Indicates.
In FIG. 6, the position of the second link 15 corresponding to the position of the first link 9 is omitted from the position of the first link 9, so the steered state of the present embodiment corresponding to the position is more specifically illustrated. It is shown in FIG. Here, FIG. 8A shows a steered state corresponding to the position A, and FIG. 8B shows a steered state corresponding to the position.

  An embodiment in which the above-described wheel steering device is provided on both sides of the vehicle body will be described.

In FIG. 9, the arm 10, the link structures 9 and 15, and the wheel 1 are provided on both sides of the vehicle body 21, the left wheel 1 </ b> L is steered by a rack member 17 </ b> L dedicated to the left wheel, and the right wheel 1 </ b> R is dedicated to the right wheel. It is a top view which shows the Example steered by the rack member 17R. The left rack member 17L meshes with the left pinion 20L, the right rack member 17R meshes with the right pinion 20R, and these pinions 20L and 20R rotate in response to a steering wheel (not shown) operated by the driver.
In normal left turn traveling, both the left rack member 17L and the right rack member 17R are moved in the right direction, and the left wheel 1L and the right wheel 1R are simultaneously steered to the left. Further, in normal right turn traveling, both the left rack member 17L and the right rack member 17R are moved leftward, and the left wheel 1L and the right wheel 1R are simultaneously steered to the right.

  On the other hand, when the vehicles are parked in parallel or moved closer to the shoulder, as shown in FIG. 10, the left rack member 17L is moved leftward while the right rack member 17R is moved rightward. The left wheel 1L and the right wheel 1R are steered to 90 degrees simultaneously.

  Thus, in the embodiment shown in FIGS. 9 to 10, the rack member 17 is provided on each of the left and right sides, and the left wheel 1L and the right wheel 1R are individually steered by the rack members 17L and 17R. It is possible to cope with both large turning traveling such as parallel parking.

  Next, another embodiment in which the steering device of the present invention is provided on both sides of the vehicle body 21 will be described.

FIG. 11 is a plan view showing an embodiment in which the left wheel 1L and the right wheel 1R are steered by a common rack member 17C. The rack member 17C meshes with one pinion 20C, and the pinion 20C rotates in response to a steering wheel (not shown) operated by the driver.
In the normal left turn traveling, the rack member 17C is moved in the right direction, and the left wheel 1L and the right wheel 1R are simultaneously steered to the left. Further, in normal right turn traveling, the rack member 17C is moved in the left direction, and the left wheel 1L and the right wheel 1R are simultaneously steered to the right.

  On the other hand, when the vehicle is parked in parallel or is brought close to the shoulder, as shown in FIG. 12, the rack member 17C is moved to the left as much as possible to move the left wheel 1L and the right wheel 1R. At the same time, it steers up to 90 degrees. In addition to that shown in FIG. 12, the left wheel 1L and the right wheel 1R can be steered up to 90 degrees simultaneously even if the rack member 17C is moved to the maximum in the right direction.

  As described above, in the embodiment shown in FIGS. 11 to 12, the common rack member 17C is moved forward and backward to steer the left wheel 1L and the right wheel 1R. It becomes possible to simplify, and it can be advantageous in terms of cost.

By the way, in this embodiment described above, the hub member 4 that rotatably supports the wheel 1 is connected to the vehicle body side by the link structures 9 and 15, and the link structures 9 and 15 rotate around the connection points 11 and 12. In the wheel steering device that steers the wheel 1 by moving, the grounding point of the wheel 1 has a long axis in the vehicle longitudinal direction as shown in FIG. Because it was configured to draw a trajectory part of an ellipse having a minor axis in the vehicle width direction,
As the turning angle of the wheel 1 is increased, the position of the wheel 1 is greatly separated from the position in the non-steering state (the wheel rotation shaft shown in FIG. 6) in the vehicle front-rear direction. Therefore, it is possible to avoid the wheel 1 being steered from interfering with the arm 10 without using the arc-shaped arm, the upper arm, and the lower arm described in Patent Documents 1 and 2, and even without increasing the unsprung mass, A big steering can be achieved.

Specifically, the part of the ellipse having the long axis in the vehicle longitudinal direction and the short axis in the vehicle width direction described above specifically passes the outermost part of the vehicle width in the non-steering state, and the turning angle increases. As you go to the inside of the car as you go,
During large turning, it is possible to reduce the protrusion of the wheel 1 to the outside of the vehicle width. Therefore, it is advantageous when bringing the vehicle close to the road shoulder.

In this embodiment, the link structure includes a first link 9 and a second link 15 longer than the first link. When the wheel 1 is not steered, the first link 9 is provided as shown in FIG. The second link 15 extends in the vehicle width direction, and is obliquely intersected with the first link 9. The second link 15 is arranged in the vehicle front-rear direction and the vehicle width direction, and the vehicle width outer end 14 of the second link 15 is connected to the hub member 4. Since the vehicle width inner end 12 of the second link 15 is connected to the arm 10 on the vehicle body side.
6, as the turning angle of the wheel 1 is increased, the position of the wheel 1 is farther away from the axis of the arm 10 in the vehicle front-rear direction, and the wheel 1 being steered interferes with the arm 10. You can avoid that. Therefore, large turning of the wheel can be achieved without increasing the unsprung mass as in Patent Documents 1 and 2.

Specifically, as shown in FIG. 1 and the like, a second connection point 12 that connects the second link 15 and the vehicle body side is a first connection point 11 that connects the first link 9 and the vehicle body side. 4th connection point 14 which arranges the 2nd link 15 and support part 8 of the hub member 4 in the non-steering state of the wheel 1 which is arranged in front of the vehicle and outside the vehicle width. Because the first link 9 and the third connecting point 13 that connects the support portion 8 of the hub member 4 are arranged behind the vehicle,
As the turning angle of the wheel 1 is increased as shown in the trajectory shown in FIG. 6, the position of the wheel 1 is farther away from the axis of the arm 10 in the vehicle front-rear direction, and the wheel 1 being steered interferes with the arm 10. You can avoid that. Therefore, large turning of the wheel can be achieved without increasing the unsprung mass as in Patent Documents 1 and 2.

More specifically, as shown in FIG. 1 and the like, the length of the support portion 8 corresponding to the distance 14 between the third connection point 13 and the fourth connection point is shorter than the second link 15, Because it was longer than the first link 9,
As the turning angle of the wheel 1 is increased as shown in the trajectory shown in FIG. 6, the position of the wheel 1 is farther away from the axis of the arm 10 in the vehicle front-rear direction, and the wheel 1 being steered interferes with the arm 10. You can avoid that. Therefore, large turning of the wheel can be achieved without increasing the unsprung mass as in Patent Documents 1 and 2.

The above description is merely an example of the present invention, and the present invention can be variously modified without departing from the spirit of the present invention.
For example, in the present embodiment, the second link 15 of the left wheel 1 shown in FIG. 1 is arranged so as to extend from the upper right to the lower left in FIG. May be. Moreover, although the vehicle body side of the link structures 9 and 15 is connected to the free end of the arm 10 that swings in the vehicle vertical direction, it is needless to say that it may be connected to other vehicle body side members.

It is a top view which shows the state which looked at the wheel steering apparatus (non-steering state) which becomes one Example of this invention from the vehicle upper direction. It is a front view which shows the state which looked at the same steering device from the vehicle front. It is the side view which looked at the same steering device from the vehicle width inside. It is a front view which shows the state which looked at the steering apparatus of the wheel which becomes the other Example of this invention from the vehicle front. It is a top view which shows the state which looked at the same steering apparatus from vehicle upper direction. It is a top view which shows the locus | trajectory of the wheel 1 grounding center of the steering apparatus shown in FIGS. It is a top view which shows the state in the case of turning a wheel to the left in the same steering apparatus, Comprising: (a) is a non-steering state (steering angle 0 degree) during straight running, (c) is large turning. The state of the rudder (steering angle of about -90 degrees) and (b) show the intermediate state (steering angle of about -45 degrees). It is a top view which shows the state in the case of turning a wheel rightward in the same steering apparatus, Comprising: (a) is a non-steering state (steering angle 0 degree) during straight running, (b) is turning right. The state of the rudder (steering angle about 30 degrees) is shown. It is a top view which shows the Example which provided the steering apparatus of this invention in the both sides of the vehicle body. It is a top view which shows the state which the wheel steered greatly in the Example. It is a top view which shows the other Example which provided the steering apparatus of this invention in the both sides of the vehicle body. It is a top view which shows the state which the wheel steered greatly in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel 2 Tire 3 Road wheel 4 Hub member 5 Strut 6 Suspension spring 7 Shock absorber 8 Hub member support part 9 1st link 10 Arm 11 1st connection point 12 2nd connection point 13 3rd connection point 14 4th connection point 15 Second link 16 Control rod 17 Rack member 18 Motor

Claims (5)

In a wheel steering device for connecting a hub member rotatably supporting a wheel to a vehicle body side by a link structure, and turning the wheel by turning the link structure around a connection point,
With the link structure, when turning, the ground contact point of the wheel is configured to draw a part of an ellipse having a long axis in the vehicle longitudinal direction and a short axis in the vehicle width direction. Steering device. In the wheel steering device according to claim 1,
A part of the ellipse passes most outward in the vehicle width in a non-steered state and heads inward in the vehicle width as the turning angle increases. In the wheel steering device according to claim 2,
The link structure includes a first link and a second link longer than the first link;
When the wheel is not steered, the first link extends in the vehicle width direction, the second link is arranged in the vehicle longitudinal direction and the vehicle width direction so as to cross the first link, and the vehicle width of the second link A wheel steering apparatus characterized in that an outer end is connected to a hub member and a vehicle width inner end of a second link is connected to a vehicle body side. In the wheel steering device according to claim 3,
A second connection point that connects the second link and the vehicle body side is disposed in front of the vehicle and outside the vehicle width from a first connection point that connects the first link and the vehicle body side,
In a non-steered state of the wheel, a fourth connection point that connects the second link and the hub member is disposed behind the vehicle than a third connection point that connects the first link and the hub member. A wheel steering device characterized by that. In the wheel steering device according to claim 4,
A wheel steering apparatus, wherein a distance between the third connection point and the fourth connection point is shorter than the second link and longer than the first link.

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