JP2020097268A - Hub unit with steering function and vehicle having the same - Google Patents

Abstract

To provide a hub unit with steering function and vehicle having the same, capable of achieving high fuel economy and running stability by giving steering of a very small angle to a steering wheel or a non-steering wheel in addition to ordinary steering of a steering wheel, capable of preventing invasion of water and foreign matter into a steering shaft peripheral part while ensuring the rigidity of a steering shaft part and capable of achieving miniaturization of the whole hub unit and reduction in the weight of the whole hub unit.SOLUTION: A hub unit 1 with steering function includes: a hub unit body; a unit support member 3 for supporting the hub unit body to rotate around a steering axial center A, a rotation allowable support member 4 which allows the rotation of the hub unit body for the unit support member 3; and a steering actuator for driving the rotation of the hub unit body, and further includes first sealing means 33 arranged between an outer ring 16 and the unit support member 3 and second sealing means 34 for covering the rotation allowable support member 4.SELECTED DRAWING: Figure 7

Description

The present invention relates to a hub unit with a steering function and a vehicle provided with the same, by controlling the left and right wheels to an appropriate steering angle according to a traveling situation, thereby improving fuel efficiency and stabilizing traveling performance and safety. Regarding technology.

In a general vehicle such as an automobile, a steering wheel and a steering device are mechanically connected, and both ends of the steering device are connected to respective left and right wheels by tie rods. Therefore, the turning angle of the left and right wheels due to the movement of the steering wheel is determined by the initial setting.
The vehicle geometry is (1) "parallel geometry" in which the left and right wheels have the same turning angle, and (2) the turning inner wheel wheel angle is cut larger than the turning outer wheel wheel angle in order to have one turning center. Ackermann geometry" is known.

Ackermann geometry is a steering angle difference between the left and right wheels so that each wheel turns around a common point in order to smoothly turn the vehicle when turning in a low speed range where centrifugal force acting on the vehicle can be ignored. Is set. However, in turning in a high speed range where the centrifugal force cannot be ignored, it is desirable that the wheels generate a cornering force in a direction in which the wheel balances the centrifugal force. Therefore, the parallel geometry is preferable to the Ackermann geometry.

As mentioned above, the steering system of a typical vehicle is mechanically connected to the wheels, so it can generally only take a single fixed steering geometry, which is the intermediate between Ackerman geometry and parallel geometry. Often set to geometrical geometry. However, in this case, the steering angle difference between the left and right wheels becomes insufficient in the low speed range, and the steering angle of the outer wheel becomes excessive, and the steering angle of the inner wheel becomes excessive in the high speed range. If there is an unnecessary bias in the wheel lateral force distribution between the inner and outer wheels in this way, it may cause deterioration of fuel efficiency due to deterioration of running resistance and early wear of tires.In addition, the inner and outer wheels cannot be efficiently used, so that cornering is smooth. There is a problem of being damaged.

DE 102 01 2206 337 specification JP, 2014-061744, A

In Patent Document 1, since two motors are used, not only the cost increases due to the increase in the number of motors but also the control becomes complicated.
In Patent Document 2, since the hub bearing is supported in a cantilever manner with respect to the steered shaft, the rigidity is lowered, and there is a possibility that the steering geometry is changed due to the occurrence of excessive traveling G.
Further, when the reduction gear is provided on the steered shaft, the size including the motor becomes large. When the overall size increases, it becomes difficult to arrange the entire structure on the inner peripheral portion of the wheel. Further, when a speed reducer having a large reduction ratio is provided, the responsiveness deteriorates.

As described above, the conventional mechanism having the auxiliary steering function is intended to arbitrarily change the toe angle or the camber angle of the wheels in the vehicle, and therefore a plurality of motors and reduction gears are required and a complicated structure is required. Has become. In addition, it becomes difficult to secure the rigidity, and in order to secure the rigidity, it is necessary to increase the size and the weight becomes heavy.
Well, since these mechanisms are provided with a mechanism having a steering function in the wheel, countermeasures against the intrusion of water and mud become an important issue, but no suggestion or suggestion has been made regarding this point.

In a vehicle, in order to arbitrarily change the toe angle or the camber angle of the wheels, a complicated structure is required, the number of constituent parts increases, the overall size becomes large and heavy. An increase in unsprung weight is likely to adversely affect vehicle driving performance such as deterioration in riding comfort.

In order to solve the above-mentioned problems of increase in size and weight, the applicant of the present application has applied for a hub unit with an auxiliary steering function (Japanese Patent Application Nos. 2017-122995, 2017-122996, etc.).
In order to prevent the infiltration of water and mud without lowering the rigidity and durability of the periphery of the steering shaft of these hub units with auxiliary steering functions, the steering shaft support used for the mechanism equipped with the steering function It is necessary to seal the inside of the bearing.

If a complicated structure is adopted as this sealing means, the overall size increases and the steered shaft is located away from the center of the wheel, and the distance from the center of the steered shaft to the ground contact surface of the wheel. However, excessive force is required to steer the vehicle. In that case, the weight of the entire hub unit is increased due to an increase in the size of the steering actuator.

An object of the present invention is to perform steering of a steered wheel or a non-steered wheel at a small angle in addition to normal steering of a steered wheel, thereby improving fuel efficiency and running stability, and at the same time, steered shaft portion. Steering that can prevent water and foreign matter from entering the periphery of the steered shaft while ensuring the rigidity of the hub unit, and can reduce the size of the entire hub unit and reduce the weight of the entire hub unit. (EN) A hub unit with a function and a vehicle including the same.

The hub unit with a steering function of the present invention includes a hub unit main body having a hub bearing for supporting a wheel and an outer ring provided on an outer peripheral surface of a fixed ring of the hub bearing,
A unit support member that is provided in the suspension frame component of the suspension device and that rotatably supports the hub unit main body around a steering axis extending in the vertical direction;
With respect to this unit support member, a rotation-allowable support component that allows rotation of the hub unit body around the turning axis,
A steering actuator that drives the hub unit body to rotate about the steering axis,
First sealing means arranged between the outer ring and the unit supporting member,
Second sealing means for covering the rotation permitting support component.

With this configuration, the hub unit main body including the hub bearing that supports the wheels can be freely rotated about the turning axis by driving the steering actuator. As a result, in addition to the normal steering of the steered wheels, the steering wheels or the non-steered wheels can be steered at a minute angle. Since the steering geometry can be changed during turning, the running stability of the vehicle can be improved. By adjusting the amount of the toe angle according to each scene even when driving straight, it is possible to make adjustments such as ensuring running stability at high speeds without lowering running resistance and reducing fuel consumption at low speeds.

Since the first sealing means is arranged between the outer ring of the hub unit main body and the unit supporting member and the second sealing means for covering the rotation permitting support component is provided, water and foreign matter enter the rotation permitting support component. Can be prevented, and the life and reliability of the rotation-allowable support component can be improved. For example, an O-ring or the like can be adopted as the first sealing means. Since it suffices to cover the rotation-allowable support component, the second sealing means can be a compact sealing means, for example, by using a thin lid-shaped sealing means. As a result, it is possible to prevent the entry of water, foreign matter, and the like into the periphery of the steering shaft while ensuring the rigidity of the steering shaft. Moreover, since the structures of the first and second sealing means can be simplified respectively, the size of the entire hub unit can be reduced and the weight of the entire hub unit can be reduced.

The rotation permitting support component is a rolling bearing arranged coaxially with the steering axis, an outer ring of the rolling bearing is installed in a fitting hole formed in the unit supporting member, and an inner ring is formed on the outer ring. Supported,
The second sealing means has a cylindrical portion fixed to the fitting hole of the unit supporting member, and a bottom surface portion which is connected to an axial base end portion of the cylindrical portion and covers the rolling bearing. Good. In this case, the second sealing means can be easily mass-produced by using a mold or the like to reduce the cost, and more reliably prevent water and foreign matters from entering from the upper or lower part of the rotation permitting support component. be able to.

The outer ring has an annular portion fixed to the outer peripheral surface of the outer ring that is the fixed ring, and a steering shaft portion that protrudes vertically from the outer periphery of the annular portion and that attaches the rotation permitting support parts, respectively. ,
The first sealing means is arranged between a flat surface portion of the annular portion which is perpendicular to the turning axis and a flat surface portion of the unit support member which faces the flat surface portion with a gap therebetween. May be.
In this case, since a simple and compact structure can be adopted as the first sealing means, it is possible to make each cross section of the steered shaft portion and the rotation permitting support component into a desired size. The rigidity of the support component can be easily ensured.

The outer ring has an annular portion fixed to the outer peripheral surface of the outer ring that is the fixed ring, and a steering shaft portion that protrudes vertically from the outer periphery of the annular portion and that mounts the rotation permitting support parts. Then
The first sealing means is provided between the outer peripheral surface of the upper and lower steering shaft portions and a part of the inner peripheral surface of the unit support member facing the outer peripheral surface of the steering shaft portion with a gap. May be arranged.
In this case, since a simple and compact structure can be adopted as the first sealing means, it is possible to make the cross section of the steered shaft portion and the rotation permitting support component into a desired size. The rigidity of the parts can be easily ensured.

A slidable elastic member may be used as the first sealing means. In this case, the structure of the first sealing means can be made compact, and the cost of the entire hub unit can be reduced.

The rotation permitting support component may be arranged in the wheel of the wheel. In this case, since the distance between the turning axis and the ground contact surface of the wheel can be shortened or reduced to zero, an excessive force for rotationally driving the hub unit body is not required, and the steering actuator can be downsized. Is possible. Therefore, the weight of the entire hub unit can be reliably reduced.

A steering system according to the present invention is a steering system including a hub unit with a steering function having any one of the above configurations according to the present invention, and a controller for controlling a steering actuator of the hub unit with a steering function. A device controls a steering actuator by outputting a current command signal corresponding to a given steering angle command signal and a current corresponding to a current command signal input from the steering control unit. And an actuator drive control unit that operates.

According to this configuration, the steering control unit outputs the current command signal according to the applied turning angle command signal. The actuator drive control unit outputs a current according to the current command signal input from the steering control unit to drive and control the steering actuator. Therefore, the wheel angle can be arbitrarily changed in addition to the steering operation by the driver's steering wheel operation.

In the vehicle of the present invention, one or both of the front wheels and the rear wheels are supported by using the hub unit with a steering function having any one of the above configurations of the present invention.
Therefore, the above-described effects of the hub unit with a steering function of the present invention can be obtained. The front wheels are generally steered wheels, but when the hub unit with a steering function of the present invention is applied to the steered wheels, it is effective for adjusting the toe angle during traveling. Although the rear wheels are generally non-steered wheels, when applied to non-steered wheels, the minimum turning radius during low-speed traveling can be reduced by slightly turning the non-steered wheels.

The hub unit with a steering function of the present invention is provided on a hub bearing supporting a wheel and a hub unit main body having an outer ring provided on an outer peripheral surface of a fixed wheel of the hub bearing, and a suspension frame component of a suspension device, A unit support member that rotatably supports the hub unit body around a steering axis extending in the vertical direction, and a rotation allowance that allows the hub support body to rotate about the steering axis about the unit support member. A support component, a steering actuator that drives the hub unit body to rotate about the turning axis, a first sealing unit that is arranged between the outer ring and the unit support member, and the rotation allowance support. Since the second sealing means for covering the parts is provided, in addition to the normal steering of the steered wheels, steering of the steered wheels or the non-steered wheels can be performed at a small angle to improve the fuel consumption and the running stability. In addition to ensuring the rigidity of the steering shaft, it is possible to prevent water and foreign matter from entering the periphery of the steering shaft, reduce the size of the entire hub unit, and reduce the weight of the entire hub unit. Can be reduced.

A steering system according to the present invention comprises: a hub unit with a steering function according to any one of the above configurations of the present invention; and a controller for controlling a steering actuator of the hub unit with a steering function. In the above steering system, the control device outputs a current command signal corresponding to a given steering angle command signal, and a current corresponding to the current command signal input from the steering control unit. In addition to the normal steering of the steered wheels, a steering wheel or a non-steered wheel can be steered at a minute angle to improve the fuel consumption and travel. In addition to improving stability, it is possible to prevent water and foreign matter from entering the periphery of the steering shaft while ensuring the rigidity of the steering shaft, and to reduce the size of the entire hub unit. The weight of the entire hub unit can be reduced.

In the vehicle according to the present invention, one or both of the front wheels and the rear wheels are supported by using the hub unit with a steering function of any of the present invention. Therefore, in addition to normal steering of the steered wheels, The steered wheels can be steered at a small angle to improve fuel efficiency and running stability, and water and foreign matter enter the periphery of the steering shaft while ensuring the rigidity of the steering shaft. This can be prevented, and the size of the entire hub unit can be reduced and the weight of the entire hub unit can be reduced.

FIG. 1 is a vertical cross-sectional view showing the configuration of a hub unit with a steering function and its periphery according to a first embodiment of the present invention. FIG. 3 is a horizontal cross-sectional view showing the configuration of the hub unit with a steering function and its periphery. It is a perspective view showing the appearance of the hub unit with the same steering function. It is a front view of the hub unit with a steering function. It is a top view of the hub unit with the same steering function. FIG. 6 is a sectional view taken along line VI-VI of FIG. 4. It is an expanded sectional view of a peripheral part of a rotation allowance support component of the hub unit with a steering function. It is an expanded sectional view of a peripheral part of a rotation allowance support component in a hub unit with a steering function concerning a 2nd embodiment of this invention. It is an expanded sectional view of a peripheral part of a rotation permission support part in a hub unit with a steering function concerning a 3rd embodiment of this invention. It is a model top view of the vehicle provided with either of the hub units with a steering function. FIG. 7 is a schematic plan view of another example of a vehicle including any hub unit with a steering function. FIG. 9 is a schematic plan view of another example of a vehicle including any hub unit with a steering function.

[First Embodiment]
A hub unit with a steering function according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7.
<Schematic structure of hub unit with steering function>
As shown in FIG. 1, the hub unit with steering function 1 includes a hub unit body 2, a unit support member 3, a rotation permitting support component 4, and first and second sealing means 33, 34 (FIG. 7). And a steering actuator 5. The unit support member 3 is provided integrally with the knuckle 6 which is a suspension frame component. The actuator body 7 of the steering actuator 5 is provided on the inboard side of the unit support member 3, and the hub unit body 2 is provided on the outboard side of the unit support member 3. With the hub unit 1 with a steering function mounted on a vehicle, the outside in the vehicle width direction of the vehicle is called the outboard side, and the center side in the vehicle width direction of the vehicle is called the inboard side.

As shown in FIGS. 2 and 3, the hub unit body 2 and the actuator body 7 are connected by a joint portion 8. Usually, a boot (not shown) is attached to the joint portion 8 for waterproofing and dustproofing.

As shown in FIG. 1, the hub unit main body 2 is supported by the unit support member 3 at two upper and lower positions via the rotation permitting support parts 4 and 4 so that the hub unit main body 2 is rotatable about a steering axis A extending in the vertical direction. Has been done. The steered shaft center A is different from the rotating shaft center O of the wheel 9, and is also different from the kingpin shaft that mainly performs steering. In a normal vehicle, the kingpin angle is set to 10 to 20 degrees for the purpose of improving straight running stability of the vehicle, but the hub unit with a steering function 1 of this embodiment has an angle different from the kingpin angle. It has a steering axis of (axis). The wheel 9 includes a wheel 9a and a tire 9b.

<Installation location of hub unit 1 with steering function>
In this embodiment, the hub unit 1 with a steering function is added to the steering of the front wheels 9F of the vehicle 10 by the steering device 11 as shown in FIG. It is provided integrally with the knuckle 6 of the suspension device 12 as a mechanism for steering about ±5 deg.

As shown in FIGS. 2 and 10, the steering device 11 is attached to the vehicle body, operates by a driver's operation of the steering wheel 11a, or operates an automatic driving device (not shown), a command from a driving support device, or the like, and moves back and forth. 14 is connected to a steering coupling portion 6d (described later) of the unit support member 3. The steering device 11 is of a rack and pinion type or the like, but any type of steering device may be used. For the suspension device 12, for example, a strut type suspension mechanism for directly fixing the shock absorber to the knuckle 6 is applied, but a double wishbone type suspension mechanism, a multi-link type suspension mechanism, or another suspension mechanism may be applied. ..

<About the hub unit body 2>
As shown in FIG. 1, the hub unit main body 2 includes a hub bearing 15 for supporting the wheels 9, an outer ring 16, and an arm portion 17 (FIG. 3) which is a steering force receiving portion described later.
As shown in FIG. 6, the hub bearing 15 includes an inner ring 18, an outer ring 19, and rolling elements 20 such as balls interposed between the inner and outer rings 18 and 19, and members on the vehicle body side and the wheels 9 (see FIG. 1) It has a role of connecting with.

In the illustrated example, the hub bearing 15 is an angular ball bearing in which the outer ring 19 is a fixed ring, the inner ring 18 is a rotating ring, and the rolling elements 20 are double rows. The inner ring 18 includes a hub ring portion 18a having a hub flange 18aa and forming a raceway surface on the outboard side, and an inner ring portion 18b forming a raceway surface on the inboard side. As shown in FIG. 1, the wheel 9a of the wheel 9 is bolted to the hub flange 18aa so as to overlap the brake rotor 21a. The inner ring 18 rotates around the rotation axis O.

As shown in FIGS. 6 and 7, the outer ring 16 is provided on the outer peripheral surface of the outer ring 19 of the hub bearing 15 and operates integrally with the outer ring 19, and is supported by the rotation permitting support component 4 described later. In this example, the outer ring 16 is fixed to the outer ring 19 of the outer ring 19 by press fitting or welding. The outer ring 16 may be an integral structure made of the same material as the outer ring 19.
The outer ring 16 includes an annular portion 16a fixed to the outer peripheral surface of the outer ring, and trunnion shaft-shaped steered shaft portions 16b and 16b provided so as to vertically project from the outer periphery of the annular portion 16a. Each of the turning shaft portions 16b extending in the substantially vertical direction is provided coaxially with the turning shaft center A.

As shown in FIG. 2, the brake 21 has a brake rotor 21a and a brake caliper 21b. The brake caliper 21b is attached to two upper and lower brake caliper mounting portions 22 (FIG. 4) formed integrally with the outer ring 19 so as to project like an arm.

<Regarding rotation-allowable support parts and unit support members>
As shown in FIGS. 6 and 7, each rotation-allowable support component 4 is a rolling bearing. In this example, a tapered roller bearing is applied as the rolling bearing. The rolling bearing includes an inner ring 4a fitted to the steered shaft portion 16b, an outer ring 4b fitted to the unit support member 3, a plurality of rolling elements 4c interposed between the inner and outer rings 4a and 4b, and these rolling elements. 4c.

The unit support member 3 has a unit support member main body 3A and a unit support member combination 3B. For example, of the upper and lower steering shaft portions 16b, 16b, the upper steering shaft portion 16b is supported by the unit support member main body 3A, and the lower steering shaft portion 16b is supported by the unit support member combination body 3B. .. In this case, the support portion 3Ab that supports the upper turning shaft portion 16b is integrally provided at the upper outboard side end of the unit support member main body 3A. A fitting hole 3Ac for fitting the outer peripheral surface of the upper rotation-allowable support component 4 is formed in the support portion 3Ab.

The unit support member combination 3B is composed of a substantially cylindrical tubular member, and a partial recess in which a part of the outer peripheral surface of the tubular member is fitted at the lower outboard side end of the unit support member main body 3A. A spherical coupled portion (not shown) is formed. A part of the outer peripheral surface of the tubular member is fitted into the joined portion to fix the unit support member combined body 3B to the unit support member main body 3A. The outer peripheral surface of the lower rotation permitting support component 4 is fitted into the fitting hole of the unit support member combination 3B. Therefore, the upper turning shaft 16b is supported by the unit support member main body 3A, and the lower turning shaft 16b is supported by the unit support member combination 3B. In addition, in FIG. 3, the unit support member 3 is shown by a dashed line.

Note that the unit support member main body 3A may have a structure in which substantially ring-shaped unit support member combinations 3B are detachably fixed to the upper and lower outboard side ends. In this case, a partial concave spherical fitting hole forming portion is formed in each of the upper and lower portions of the outboard side end of the unit support member main body 3A. Partial concave spherical fitting holes are formed in the upper and lower parts of the inboard side surface of the unit support member combination 3B. The unit support member combination 3B is fixed to the outboard side end of the unit support member main body 3A, and the fitting hole forming portions are combined with each other in the upper and lower parts, thereby forming the fitting holes that are continuous all around. .. The outer ring 4b (FIG. 6) is fitted in this fitting hole.

As shown in FIGS. 6 and 7, a female screw portion is formed on each of the mounting shaft portions 16b so as to extend in the radial direction, and a bolt 23 that is screwed into the female screw portion is provided. A disc-shaped pressing member 24 is interposed on the end surface of the inner ring 4a, and a pressing force is applied to the end surface of the inner ring 4a by a bolt 23 that is screwed to the female thread portion, so that each rotation-allowable support component 4 is preloaded. I'm giving. This can increase the rigidity of each rotation-allowable support component 4. As the rolling bearing of the rotation-allowable support component 4, an angular contact ball bearing or a four-point contact ball bearing may be used instead of the tapered roller bearing. In that case as well, the preload can be applied in the same manner as described above.

As shown in FIG. 1, the upper and lower steered shaft portions 16b and 16b are supported by the unit support member 3 via the rotation allowance support parts 4 and 4, respectively, and each rotation allowance support part 4 is inside the wheel 9a of the wheel 9. Located in. In this example, each rotation-allowable support component 4 is arranged in the wheel 9a near the middle of the wheel 9a in the width direction.

As shown in FIG. 2, the arm portion 17 is a portion serving as a point of action that gives an auxiliary steering force to the outer ring 19 of the hub bearing 15, and integrally projects with a part of the outer circumference of the outer ring 16. The arm portion 17 is rotatably connected to the linear motion output portion 25 a of the steering actuator 5 via the joint portion 8. As a result, the linear motion output portion 25a of the steering actuator 5 advances and retreats, so that the hub unit body 2 rotates around the steering axis A (FIG. 1), that is, auxiliary steering is performed.

<About sealing means>
FIG. 7A is an enlarged cross-sectional view of the peripheral portion of the rotation permitting support component 4 of the hub unit 1 with a steering function, and FIG. 7B is a partially enlarged view of the VII(b) portion of FIG. 7A. is there.
<First sealing means 33>
The first sealing means 33 is arranged between the outer ring 16 and the unit support member 3, and the second sealing means 34, which will be described later, covers the upper and lower rotation permitting support parts 4, 4. In the annular portion 16a of the outer ring 16, the plane portions 35 that are perpendicular to the steering axis A are formed at the upper and lower portions of the upper and lower steering shaft portions 16b, 16b in a certain phase, that is, in the circumferential direction. There is. In other words, each flat surface portion 35 is formed perpendicular to the steered shaft center A around the base end portion of each steered shaft portion 16b.

The first sealing means is provided between the flat portion 35 of the annular portion 16a perpendicular to the steering axis A and the flat portion 36 of the unit support member 3 which faces the flat portion 35 with a gap δ1 therebetween. 33 are arranged respectively. An annular groove 35a around the turning axis A is formed in each flat surface portion 35 of the annular portion 16a, and the first sealing means 33 is fitted in each annular groove 35a. An elastic member such as a slidable O-ring is used as the first sealing means 33. A lubricant is applied to the elastic member fitted in the annular groove 35a for use. The elastic member fitted in the annular groove 35a is crushed by the flat surface portion 36 of the unit support member 3 and elastically deformed, so that the gap δ1 can be sealed. Instead of the configuration in which the annular groove 35a is formed in the flat surface portion 35 of the annular portion 16a, an annular groove is formed in the flat surface portion 36 of the unit support member 3, and the annular groove of the flat surface portion 36 of the unit support member 3 is formed. The first sealing means 33 may be fitted.

<Second sealing means>
The second sealing means 34 is a thin lid-shaped sealing means and is fixed to the unit supporting member 3. Specifically, the second sealing means 34 is formed in a substantially cylindrical shape with a bottom, and is connected to a large-diameter cylindrical portion 34a fixed to the unit supporting member 3 and an axial base end portion of the cylindrical portion 34a. And a bottom surface portion 34b. The bottom surface portion 34b is formed concentrically with a large-diameter cylindrical portion 34a that axially protrudes from a disk portion 34ba that extends in the radial direction from the axial base end portion of the cylindrical portion 34a and the center of the circular disk portion 34ba. It has a small-diameter cylindrical portion 34bb and a bottom portion 34bc that covers the axial base end portion of the small-diameter cylindrical portion 34bb.

Regarding the upper second sealing means 34 shown in FIG. 7A, the large-diameter cylindrical portion 34a is fitted and fixed in, for example, the fitting hole 3Ac of the unit support member main body 3A. Regarding the lower second sealing means 34 (FIG. 1), the large-diameter cylindrical portion 34a is fitted and fixed, for example, on the inner peripheral surface of the unit support member combination body 3B (FIG. 1) of a tubular member. It The small-diameter cylindrical portion 34bb is formed to have a smaller diameter than the large-diameter cylindrical portion 34a. The head of the bolt 23 is covered with a small diameter cylindrical portion 34bb and a bottom portion 34bc, and the pressing member 24 and the rotation permitting support component 4 are mainly covered with a disk portion 34ba and a large diameter cylindrical portion 34a. Further, the second sealing means 34 is provided with the small-diameter cylindrical portion 34bb and the disc portion 34ba, thereby preventing the interference with the brake rotor 21a.

<Steering actuator 5>
As shown in FIG. 3, the steering actuator 5 has an actuator body 7 that drives the hub unit body 2 to rotate about the steered axis A (FIG. 1).
As shown in FIG. 2, the actuator main body 7 converts the motor 26, the speed reducer 27 that reduces the rotation of the motor 26, and the forward and reverse rotation outputs of the speed reducer 27 into the reciprocating linear motion of the linear motion output unit 25a. And a direct-acting mechanism 25. The motor 26 is, for example, a permanent magnet type synchronous motor, but may be a DC motor or an induction motor.

The speed reducer 27 can use a winding type transmission mechanism such as a belt transmission mechanism or a gear train, and the belt transmission mechanism is used in the example of FIG. The speed reducer 27 has a drive pulley 27a, a driven pulley 27b, and a belt 27c. A drive pulley 27a is connected to the motor shaft of the motor 26, and a driven pulley 27b is provided in the linear motion mechanism 25. The driven pulley 27b is arranged parallel to the motor shaft. The driving force of the motor 26 is transmitted from the drive pulley 27a to the driven pulley 27b via the belt 27c. The drive pulley 27a, the driven pulley 27b and the belt 27c constitute a winding type speed reducer 27.

A feed screw mechanism such as a slide screw or a ball screw, or a rack and pinion mechanism can be used as the linear motion mechanism 25. In this example, a feed screw mechanism using a trapezoidal screw slide screw is used. Since the linear motion mechanism 25 includes the feed screw mechanism using the trapezoidal screw slide screw, it is possible to enhance the effect of preventing reverse input from the tire 9b. The actuator body 7 including the motor 26, the speed reducer 27, and the linear motion mechanism 25 is assembled as a subassembly and is detachably attached to the case 6b with bolts or the like. A mechanism for directly transmitting the driving force of the motor 26 to the linear motion mechanism 25 without using a speed reducer is also possible.

The case 6b is formed integrally with the unit support member main body 3A as a part of the unit support member 3. The case 6b is formed in a bottomed tubular shape, and is provided with a motor housing portion that supports the motor 26 and a linear motion mechanism housing portion that supports the linear motion mechanism 25. A fitting hole for supporting the motor 26 at a predetermined position in the case is formed in the motor housing portion. The linear motion mechanism accommodating portion is formed with a fitting hole for supporting the linear motion mechanism 25 at a predetermined position in the case, a through hole for allowing the linear motion output portion 25a to advance and retract, and the like.

As shown in FIG. 3, the unit support member main body 3A includes the case 6b, a shock absorber mounting portion 6c which is a shock absorber mounting portion, and a steering device coupling portion 6d which is a coupling portion of the steering device 11 (FIG. 2). Have. The shock absorber mounting portion 6c and the steering device coupling portion 6d are also integrally formed on the unit support member main body 3A. A shock absorber mounting portion 6c is formed so as to project above the outer surface of the unit support member main body 3A. A steering device coupling portion 6d is formed so as to project on a side surface portion of the outer surface portion of the unit support member main body 3A.

<Effect>
According to the hub unit 1 with a steering function described above, the hub unit main body 2 including the hub bearing 15 that supports the wheels 9 can be freely rotated around the turning axis A by driving the actuator main body 7. .. This rotation is added to the steering operation by the driver's steering wheel, that is, added to the rotation of the knuckle 6 around the kingpin axis by the steering device 11, and is performed as auxiliary steering, and one-wheel independent steering can be performed. .. The toe angle between the left and right wheels 9 and 9 can be arbitrarily changed by changing the angle of the auxiliary steering of the left and right wheels 9 and 9.

Therefore, the hub unit 1 with a steering function may be used for both steered wheels such as front wheels and non-steered wheels such as rear wheels. When used as a steered wheel, the wheel 9 is installed on a member whose direction can be changed by the steering device 11 so as to be added to the steering by the driver's steering wheel operation, and the wheel 9 can be individually operated on the left and right wheels, or can be linked to the left and right wheels. It becomes a mechanism to make a minute angle change. Regarding the angle of the auxiliary steering, a small angle is sufficient to improve the kinetic performance of the vehicle and the stability and safety of traveling, and it is sufficient even if the auxiliary steering possible angle is ±5 degrees or less. The angle of the auxiliary steering is controlled by the steering actuator 5.

Further, when turning, it is possible to change the steering angle difference between the left and right wheels according to the traveling speed. For example, the steering geometry can be changed during traveling, such as parallel geometry for high-speed turning and Ackermann geometry for low-speed turning. Since the wheel angle can be arbitrarily changed during traveling as described above, it becomes possible to improve the kinetic performance of the vehicle and to travel stably and safely. By appropriately changing the steering angles of the left and right steered wheels during turning, it is possible to reduce the turning radius of the vehicle and improve the small turning performance.
Furthermore, by adjusting the amount of the toe angle according to each scene even when driving straight, it is possible to make adjustments such as ensuring running stability at high speed without lowering running resistance and worsening fuel consumption at low speed.

When the hub unit 1 with a steering function is applied to the non-steering wheels that are the rear wheels 9R, if the steering angle is in the same phase as the front wheels 9F during turning, yaw that occurs during steering is suppressed and vehicle stability is improved. be able to. By adjusting the toe angle independently on the right and left even when driving straight, it is possible to ensure running stability.
However, the mechanism for steering around the turning axis A in the wheel 9a needs to ensure waterproofness and dustproofness.

In the hub unit 1 with a steering function, in particular, the first sealing means 33 is arranged between the outer ring 16 of the hub unit main body 2 and the unit supporting member 3 and the second sealing for covering the rotation permitting support component 4 is provided. Since the means 34 is provided, it is possible to prevent water, foreign matter, and the like from entering the rotation-permitting support component 4, and improve the life and reliability of the rotation-permitting support component 4. An O-ring or the like can be adopted as the first sealing means 33. Since the second sealing means 34 only needs to cover the rotation-allowable support component 4, the second sealing means 34 can be a compact sealing means by using a thin lid-shaped sealing means. As a result, the rigidity of the steered shaft portion 16b can be ensured and water and foreign matter can be prevented from entering the peripheral portion of the steered shaft. Further, since the structures of the first and second sealing means 33 and 34 can be simplified respectively, the size of the entire hub unit can be reduced and the weight of the entire hub unit can be reduced.

The second sealing means 34 is formed in a substantially cylindrical shape with a bottom, and has a cylindrical portion 34a fixed to the unit support member 3, and a bottom surface portion 34b connected to the axial base end portion of the cylindrical portion 34a. is there. Therefore, the second sealing means 34 can be easily mass-produced by using a mold or the like to reduce the cost, and water and foreign matter can be more reliably prevented from entering from the upper or lower portion of the rotation-allowable support component 4. Can be prevented.

The first sealing means is provided between the flat portion 35 of the annular portion 16a perpendicular to the steering axis A and the flat portion 36 of the unit support member 3 which faces the flat portion 35 with a gap δ1 therebetween. Since 33 is arranged, a simple and compact structure can be adopted as the first sealing means 33. Thereby, each cross section of the steered shaft portion 16b and the rotation allowance support component 4 can be made into a desired size, and the rigidity of the steered shaft portion 16b and the rotation allowance support component 4 can be easily ensured. .. Further, since the first sealing means 33 is arranged between the flat surface portion 35 of the annular portion 16a and the flat surface portion 36 of the unit supporting member 3, the outer peripheral surface of the steered shaft portion 16b and the unit supporting member 3 are arranged. The vertical dimension of the steered shaft portion 16b can be shortened, and a compact design is possible, compared with the configuration (FIG. 8) described later in which the first sealing means 33 is arranged between a part of the inner peripheral surface of the steering wheel shaft 16b. Becomes

Since the rotation permitting support component 4 is located inside the wheel 9a of the wheel 9, the distance between the turning axis A and the ground contact surface of the wheel 9 can be shortened or reduced to zero. As a result, it is possible to reduce the size of the steering actuator 5 without requiring an excessive force for rotationally driving the hub unit body 2. Therefore, the weight of the entire hub unit can be reliably reduced.

<About other embodiments>
In the following description, the parts corresponding to the items previously described in the respective embodiments will be designated by the same reference numerals, and overlapping description will be omitted. When only a part of the structure is described, the other parts of the structure are the same as those described above unless otherwise specified. The same operation and effect are obtained from the same configuration. Not only the combination of the parts specifically described in each of the embodiments, but also the embodiments may be partially combined as long as there is no particular problem in the combination.

[Second Embodiment]
FIG. 8A is an enlarged sectional view of a peripheral portion of the rotation permitting support component 4 in the hub unit with a steering function 1 according to the second embodiment of the present invention, and FIG. 8B is FIG. 8A. FIG. 8 is a partially enlarged view of part VIII(b) of FIG. The second embodiment differs from the first embodiment only in the configuration of the first sealing means 33, and the second sealing means 34 has the same configuration as that of the first embodiment.

In this hub unit 1 with a steering function, a part of the unit support member 3 that faces the outer peripheral surfaces of the upper and lower steered shaft portions 16b on the base end side and the outer peripheral surface of each steered shaft portion 16b with a gap δ2 therebetween. The first sealing means 33 is arranged between the inner peripheral surface and the inner peripheral surface. Regarding the upper side first sealing means 33, the upper side supporting portion 3Ab of the unit supporting member main body 3A corresponds to “a part of the unit supporting member 3”, and regarding the lower side first sealing means (not shown), The unit support member combination 3B (FIG. 1) corresponds to "a part of the unit support member 3".

An annular groove 37 is formed on the outer peripheral surface of each of the steered shaft portions 16b on the base end side, and the first sealing means 33, which is an elastic member such as an O-ring, is fitted in each annular groove 37. .. The elastic member fitted in the annular groove 37 is crushed by a part of the unit supporting member 3 and elastically deformed, whereby the gap δ2 can be sealed.

Also in this configuration, since the simple and compact structure can be adopted as the first sealing means 33, the cross section of the steered shaft portion 16b and the rotation permitting support component 4 can be made to have a desired size. The rigidity of the portion 16b and the rotation permitting support component 4 can be easily ensured.
Note that instead of the configuration in which the annular groove 37 is formed on the outer peripheral surface of the steered shaft portion 16b, an annular groove is formed in a part of the unit supporting member 3, and the annular groove formed in the unit supporting member 3 is One sealing means 33 may be fitted.

[Third Embodiment]
As shown in FIG. 9, a part of the inner peripheral surface of the unit support member 3 that faces the outer peripheral surfaces of the upper and lower steering shaft portions 16b on the base end side and the outer peripheral surfaces of the respective steering shaft portions 16b with a gap. A first sealing means 33, which is an oil seal, may be disposed between and.

<Application to non-steering wheels>
The hub unit with a steering function 1 may be used for non-steering wheels. For example, as shown in FIG. 11, in a vehicle with front-wheel steering, it may be set to the undercarriage frame component 6R that serves as a wheel bearing installation portion of the suspension device 12R that supports the rear wheels 9R and may be used for rear-wheel steering.
Others As shown in FIG. 12, the hub unit with steering function 1 may be used for the left and right front wheels 9F, 9F that are steered wheels and the left and right rear wheels 9R, 9R that are non-steered wheels, respectively.

<About steering system>
As shown in FIG. 3, this steering system includes a steering function-equipped hub unit 1 according to any one of the embodiments, and a control device 29 that controls the steering actuator 5 of the steering function-equipped hub unit 1. The controller 29 has a steering controller 30 and an actuator drive controller 31. The steering control unit 30 outputs a current command signal according to the auxiliary steering angle command signal (steering angle command signal) given from the upper control unit 32.

The higher-order control unit 32 is a higher-order control unit of the steering control unit 30, and as the higher-order control unit 32, for example, an electric control unit (VCU) for controlling the entire vehicle is applied. The actuator drive control unit 31 outputs a current according to the current command signal input from the steering control unit 30 to drive and control the steering actuator 5. The actuator drive control unit 31 controls the electric power supplied to the coil of the motor 26. The actuator drive control unit 31 constitutes, for example, a half bridge circuit using a switch element (not shown), and performs PWM control for determining the motor applied voltage based on the ON-OFF duty ratio of the switch element. As a result, the angle of the wheel can be slightly changed in addition to the steering operation by the driver's steering wheel operation. Even when driving straight, the amount of toe angle can be adjusted to suit each scene.

The steering system may operate the steering actuators 5 and 5 in accordance with a command from an automatic driving device (not shown), a driving support device, or the like, instead of the driver operating the steering wheel.
The embodiments for carrying out the present invention have been described above based on the embodiments, but the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

2... Hub unit main body, 3... Unit support member, 4... Rotation allowance support component, 4b... Outer wheel, 5... Steering actuator, 6... Knuckle (underbody frame component), 9... Wheel, 10... Vehicle, 12, 12R ... Suspension device, 15... Hub bearing, 16... Outer ring, 16a... Annular part, 16b... Steering shaft part, 29... Control device, 30... Steering control part, 31... Actuator drive control part, 33... First Sealing means, 34... Second sealing means, 34a... Cylindrical part, 34b... Bottom part

Claims (8)

A hub unit main body having a hub bearing for supporting a wheel and an outer ring provided on an outer peripheral surface of a fixed ring of the hub bearing,
A unit support member that is provided in the suspension frame component of the suspension device and that rotatably supports the hub unit main body around a steering axis extending in the vertical direction;
With respect to this unit support member, a rotation-allowable support component that allows rotation of the hub unit body around the turning axis,
A steering actuator that drives the hub unit body to rotate about the steering axis,
First sealing means arranged between the outer ring and the unit supporting member,
A hub unit with a steering function, comprising: a second sealing unit that covers the rotation-permitting support component. The hub unit with a steering function according to claim 1, wherein the rotation permitting support component is a rolling bearing arranged coaxially with the turning axis, and an outer ring of the rolling bearing is formed on the unit supporting member. Installed in the fitting hole, the inner ring is supported by the outer ring,
The second sealing means includes a cylindrical portion fixed to the fitting hole of the unit support member, and a bottom surface portion that is connected to an axial base end portion of the cylindrical portion and covers the rolling bearing. unit. The hub unit with a steering function according to claim 1 or 2, wherein the outer ring is an annular portion fixed to an outer peripheral surface of the outer ring, which is the fixed ring, and vertically from the outer periphery of the annular portion. A steering shaft portion that projects and attaches each of the rotation permitting support parts,
The first sealing means is arranged between a flat surface portion of the annular portion which is perpendicular to the turning axis and a flat surface portion of the unit support member which faces the flat surface portion with a gap therebetween. Hub unit with steering function. The hub unit with a steering function according to claim 1 or 2, wherein the outer ring is an annular portion fixed to an outer peripheral surface of the outer ring, which is the fixed ring, and vertically from the outer periphery of the annular portion. A steering shaft portion that projects and attaches each of the rotation permitting support parts,
The first sealing means is provided between the outer peripheral surface of the upper and lower steering shaft portions and a part of the inner peripheral surface of the unit support member facing the outer peripheral surface of the steering shaft portion with a gap. A hub unit with a steering function in which is installed. The hub unit with a steering function according to any one of claims 1 to 4, wherein a slidable elastic member is used as the first sealing means. The hub unit with a steering function according to any one of claims 1 to 5, wherein the rotation permitting support component is arranged inside the wheel of the wheel. A steering system comprising: the hub unit with a steering function according to any one of claims 1 to 6; and a controller for controlling a steering actuator of the hub unit with a steering function. Is a steering control unit that outputs a current command signal corresponding to a given steering angle command signal, and outputs a current corresponding to the current command signal input from the steering control unit to drive and control the steering actuator. A steering system having an actuator drive controller. A vehicle in which one or both of front wheels and rear wheels are supported by using the hub unit with a steering function according to any one of claims 1 to 6.

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