JP7177681B2 - HUB UNIT WITH STEERING FUNCTION AND VEHICLE INCLUDING THE SAME - Google Patents

Description

The present invention relates to a hub unit with a steering function and a vehicle equipped with the same. By controlling the steering angle of the left and right wheels appropriately according to the driving conditions, it aims to improve fuel consumption, stability of driving performance, and safety. Regarding technology.

In a vehicle such as a general automobile, a steering wheel and a steering device are mechanically connected, and both ends of the steering device are connected to 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 settings.
The vehicle geometry includes (1) "parallel geometry" in which the left and right wheels have the same turning angle, and (2) "turning inner wheel angle larger than turning outer wheel angle" in order to keep the turning center in one place. Ackermann Geometry" is known.

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

As mentioned above, a typical vehicle steering system is mechanically connected to the wheels, so it is generally possible to have only a single fixed steering geometry, which is intermediate between the Ackermann geometry and the parallel geometry. It is often set to a typical geometry. However, in this case, the steering angle difference between the left and right wheels is insufficient in the low speed range, resulting in an excessive steering angle of the outer wheels, and an excessive steering angle of the inner wheels in the high speed range. Unnecessary imbalance in the wheel lateral force distribution between the inner and outer wheels causes deterioration of fuel efficiency and premature wear of tires due to worsening of running resistance. There is the issue of damage.

DE 102012206337 A1 JP 2014-061744 A

In Patent Document 1, since two motors are used, the increase in the number of motors not only causes an increase in cost but also complicates control.
In Patent Document 2, since the hub bearing is cantilevered with respect to the steering shaft, the rigidity is lowered, and there is a possibility that the steering geometry may change due to the generation of excessive traveling G.
In addition, when a speed reducer is provided on the steering shaft, the size including the motor becomes large. As the overall size increases, it becomes difficult to place the entire on the inner circumference of the wheel. Moreover, when a reduction gear with a large reduction ratio is provided, the responsiveness deteriorates.

As described above, conventional mechanisms with an auxiliary steering function are intended to arbitrarily change the toe angle or camber angle of the wheels of a vehicle, and therefore require multiple motors and speed reduction mechanisms, resulting in a complicated configuration. It 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, which increases the weight.
Well, since these mechanisms are provided with a steering function inside the wheel, countermeasures against intrusion of water and mud are an important issue, but no suggestion or proposal has been made on this point.

In order to arbitrarily change the toe angle or camber angle of the wheels in a vehicle, a complicated configuration is required, the number of components increases, and the overall size and weight increases. An increase in unsprung weight may adversely affect vehicle driving performance, such as deterioration of ride comfort.

In order to solve the above problems of increased size and weight, the present applicant has applied for a hub unit with an auxiliary steering function (Japanese Patent Application No. 2017-122995, Japanese Patent Application No. 2017-122996, etc.).
In order to prevent the ingress of water and mud without reducing the rigidity and durability of the steering shaft periphery of these hub units with auxiliary steering function, the steering shaft support used in the mechanism with the steering function is required. The inside of the bearing must be sealed.

If a complicated structure is adopted as this sealing means, the overall size increases, the steered shaft is configured at a position 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 is long and requires excessive force to steer. In that case, the weight of the entire hub unit increases, such as the size of the steering actuator.

An object of the present invention is to enable steering of steered wheels or non-steered wheels at a minute angle in addition to normal steering of the steered wheels, thereby improving fuel efficiency and driving stability, etc. While securing the rigidity of the steering shaft, it is possible to prevent water and foreign matter from entering the periphery of the steering shaft, and to reduce the size and weight of the entire hub unit. An object of the present invention is to provide a functional hub unit and a vehicle equipped with the same.

A hub unit with a steering function of the present invention comprises a hub unit body having a hub bearing for supporting a wheel and an outer ring provided on the outer peripheral surface of a fixed wheel of the hub bearing;
a unit support member provided on a suspension frame part of a suspension system for supporting the hub unit body rotatably around a steering shaft extending in the vertical direction;
a rotation-allowing support member that allows the hub unit main body to rotate about the steering axis with respect to the unit support member;
a steering actuator that rotationally drives the hub unit body about the turning axis;
a first sealing means disposed between the outer ring and the unit support member;
and a second sealing means covering the rotation-permitting support component.

According to this configuration, the hub unit body including the hub bearings that support 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, steering of the steered wheels or the non-steered wheels can be performed at a very small angle. Since the steering geometry can be changed during cornering, the running stability of the vehicle can be improved. Even when driving in a straight line, by adjusting the amount of toe angle according to each situation, it is possible to reduce driving resistance at low speeds without deteriorating fuel efficiency, and to ensure driving stability at high speeds.

Since the first sealing means is arranged between the outer ring of the hub unit main body and the unit support member and the second sealing means is provided to cover the rotation-permitting support parts, water and foreign matter are prevented from entering the rotation-permitting support parts. , and the life and reliability of the rotatable support components can be improved. For example, an O-ring or the like may be employed as the first sealing means. Since it is sufficient for the second sealing means to cover the rotation-permitting support component, for example, by using a thin lid-shaped sealing means, the sealing means can be made compact. As a result, it is possible to prevent water, foreign matter, and the like from entering the periphery of the steering shaft while ensuring the rigidity of the steering shaft. Further, since the structures of the first and second sealing means can be simplified, the overall size and weight of the hub unit can be reduced.

The rotation-permitting support component is a rolling bearing that is arranged coaxially with the steering axis, the outer ring of this rolling bearing is installed in a fitting hole formed in the unit support member, and the inner ring is attached to the outer ring. supported,
The second sealing means has a cylindrical portion fixed to the fitting hole of the unit support member, and a bottom portion connected to the axial base end portion of the cylindrical portion and covering the rolling bearing. good too. In this case, the second sealing means can be easily mass-produced using a mold or the like, thereby reducing costs, and more reliably preventing water, foreign matter, etc. from entering from the top or bottom of the rotation-permitting support part. be able to.

The outer ring has an annular portion fixed to the outer peripheral surface of the outer ring, which is the stationary ring, and steering shaft portions projecting vertically from the outer periphery of the annular portion and on which the rotation-allowing support parts are respectively mounted. ,
The first sealing means is arranged between a plane portion of the annular portion perpendicular to the turning axis and a plane portion of the unit support member facing each other with a gap between the plane portions. may
In this case, since a simple and compact structure can be adopted as the first sealing means, each cross-section of the steering shaft portion and the rotation-permitting support component can be made to have a desired size. 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, which is the fixed ring, and steering shaft portions protruding vertically from the outer periphery of the annular portion to which the rotation-allowing support parts are mounted. death,
The first sealing means is provided between the outer peripheral surfaces of the upper and lower steered shaft portions and the inner peripheral surface of a part of the unit support member facing the outer peripheral surfaces of the steered shaft portions with a gap therebetween. may be placed.
In this case, since a simple and compact structure can be adopted as the first sealing means, the cross sections of the turning shaft portion and the rotation-permitting support component can be made to desired sizes. Rigidity of 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 within the wheel of the wheel. In this case, since the distance between the steering axis and the ground contact surface of the wheel can be shortened or eliminated, an excessive force for rotationally driving the hub unit body is not required, and the size of the steering actuator can be reduced. becomes possible. Therefore, the weight of the entire hub unit can be reliably reduced.

A steering system according to the present invention includes a hub unit with a steering function having any one of the above configurations of the present invention, and a control device for controlling a steering actuator of the hub unit with a steering function, wherein the control The device includes a steering control section that 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 section to drive and control the steering actuator. and an actuator drive control unit.

According to this configuration, the steering control section outputs a current command signal corresponding to the given steering angle command signal. The actuator drive control section outputs a current corresponding to the current command signal input from the steering control section to drive and control the steering actuator. Therefore, the wheel angle can be arbitrarily changed in addition to the steering by the steering wheel operation of the driver.

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

A hub unit with a steering function according to the present invention includes a hub unit main body having a hub bearing for supporting a wheel and an outer ring provided on the outer peripheral surface of a fixed wheel of the hub bearing, and a suspension frame part of a suspension system, a unit support member that supports the hub unit body rotatably around a steering shaft extending in the vertical direction; and a rotation allowance that allows rotation of the hub unit body around the steering shaft center with respect to the unit support member. a support component, a steering actuator for rotationally driving the hub unit body about the steering axis, a first sealing means arranged between the outer ring and the unit support member, and the rotation-allowing support. and a second sealing means for covering the parts, so that in addition to the normal steering of the steered wheels, the steered wheels or the non-steered wheels can be steered at a small angle, improving fuel efficiency and driving stability. In addition, it is possible to prevent water and foreign matter from entering the peripheral portion of the steering shaft while ensuring the rigidity of the steering shaft portion, 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 includes a hub unit with a steering function according to any one of the structures of the present invention, and a control device for controlling a steering actuator of the hub unit with a steering function. The steering system comprises a steering control unit that 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. and the actuator drive control unit for driving and controlling the steering actuator, in addition to the normal steering of the steered wheels, the steered wheels or the non-steered wheels can be steered at a small angle, improving fuel consumption and driving. It is possible to improve the stability of the steering shaft, prevent water and foreign matter from entering the vicinity of the steering shaft while ensuring the rigidity of the steering shaft, and reduce the size of the entire hub unit. It is possible to reduce the weight of the entire hub unit.

In the vehicle of the present invention, one or both of the front wheels and the rear wheels are supported using the hub unit with steering function of any configuration of the present invention. It is possible to steer the non-steered wheels at a very small angle, thereby improving fuel consumption and driving stability, while ensuring the rigidity of the steering shaft while preventing water and foreign matter from entering the area around the steering shaft. In addition, the overall size and weight of the hub unit can be reduced.

1 is a vertical cross-sectional view showing the structure of a hub unit with a steering function and its surroundings according to a first embodiment of the present invention; FIG. FIG. 3 is a horizontal cross-sectional view showing the structure of the hub unit with steering function and its surroundings; It is a perspective view which shows the external appearance of the hub unit with a steering function. It is a front view of the hub unit with a steering function. It is a top view of the same hub unit with a steering function. FIG. 5 is a sectional view taken along line VI-VI of FIG. 4; 4 is an enlarged cross-sectional view of a peripheral portion of a rotation-permitting support component of the hub unit with steering function; FIG. FIG. 7 is an enlarged cross-sectional view of a peripheral portion of a rotation-allowing support component in a hub unit with steering function according to a second embodiment of the present invention; FIG. 11 is an enlarged cross-sectional view of a peripheral portion of a rotation-allowing support component in a hub unit with steering function according to a third embodiment of the present invention; 1 is a schematic plan view of a vehicle provided with any hub unit with steering function; FIG. FIG. 10 is a schematic plan view of another example of a vehicle provided with any hub unit with steering function; FIG. 10 is a schematic plan view of another example of a vehicle provided with any hub unit with steering function;

[First embodiment]
A hub unit with a steering function according to an embodiment of the invention will be described with reference to FIGS. 1 to 7. FIG.
<Schematic structure of hub unit with steering function>
As shown in FIG. 1, the steering hub unit 1 includes a hub unit body 2, a unit support member 3, a rotation-allowing support member 4, and first and second sealing means 33 and 34 (FIG. 7). and a steering actuator 5 . A unit support member 3 is provided integrally with a knuckle 6, which is an underbody frame component. The actuator main body 7 of the steering actuator 5 is provided on the inboard side of the unit support member 3 , and the hub unit main body 2 is provided on the outboard side of the unit support member 3 . When the hub unit 1 with a steering function is mounted on the vehicle, the vehicle width direction outer side of the vehicle is called the outboard side, and the vehicle width direction central side 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 . Normally, this joint portion 8 is attached with a boot (not shown) for waterproofing and dustproofing.

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

<Location of hub unit 1 with steering function>
In this embodiment, the steering function-equipped hub unit 1 is used to steer the steered wheels, specifically, the front wheels 9F of the vehicle 10 as shown in FIG. ±5 degrees) is provided integrally with the knuckle 6 of the suspension system 12 .

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

<Regarding the hub unit body 2>
As shown in FIG. 1, the hub unit main body 2 includes a hub bearing 15 for supporting the wheel 9, an outer ring 16, and an arm portion 17 (FIG. 3) as a steering force receiving portion described later.
As shown in FIG. 6, the hub bearing 15 has an inner ring 18, an outer ring 19, and rolling elements 20 such as balls interposed between the inner and outer rings 18, 19. 1) It serves as a link between

In the illustrated example, the hub bearing 15 is an angular contact 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 has a hub ring portion 18a having a hub flange 18aa and forming an outboard side raceway surface, and an inner ring portion 18b forming an inboard side raceway surface. 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, operates integrally with the outer ring 19, and is supported by the rotation-allowing support component 4, which will be described later. In this example, the outer ring 16 is fixed to the outer ring 19 by press-fitting or welding to the outer peripheral surface of the outer ring 19 . Note that the outer ring 16 may be made of the same material as the outer ring 19 and may have an integral structure.
The outer ring 16 has an annular portion 16a fixed to the outer peripheral surface of the outer ring, and trunnion shaft-like steerable shaft portions 16b, 16b protruding vertically from the outer periphery of the annular portion 16a. Each steered shaft portion 16b extending in a substantially vertical direction is provided coaxially with the steered shaft center A. As shown in FIG.

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 attachment portions 22 (FIG. 4) formed integrally with the outer ring 19 so as to protrude in the form of arms.

<Regarding rotation-permitting support parts and unit support members>
As shown in FIGS. 6 and 7, each rotation-permitting support component 4 consists of a rolling bearing. In this example, tapered roller bearings are used as rolling bearings. The rolling bearing includes an inner ring 4a fitted to the steering 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 combined body 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 combined unit support member assembly 3B. . In this case, a support portion 3Ab that supports the upper steering shaft portion 16b is provided integrally with the upper outboard side end of the unit support member main body 3A. A fitting hole 3Ac into which the outer peripheral surface of the outer ring of the upper rotation-permitting support component 4 is fitted is formed in the support portion 3Ab.

The unit support member assembly 3B is composed of a substantially cylindrical tubular member, and the lower outboard side end of the unit support member main body 3A is partially recessed into which a part of the outer peripheral surface of the tubular member is fitted. A spherical coupling part (not shown) is formed. A portion of the outer peripheral surface of the tubular member is fitted into the coupled portion to fix the unit supporting member assembly 3B to the unit supporting member main body 3A. The outer peripheral surface of the outer ring of the lower rotation-permitting support component 4 is fitted into the fitting hole of the unit support member assembly 3B. Therefore, 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 combined unit support member 3B. In addition, in FIG. 3, the unit support member 3 is represented by a dashed line.

It should be noted that a structure may be adopted in which substantially ring-shaped unit support member combined bodies 3B are detachably fixed to the upper and lower outboard side ends of the unit support member main body 3A. In this case, the upper and lower portions of the outboard side end of the unit support member main body 3A are respectively formed with partially concave spherical fitting hole forming portions. Partial concave spherical fitting hole forming portions are respectively formed in the upper and lower portions of the inboard side surface of the unit support member combination 3B. A unit support member assembly 3B is fixed to the outboard side end of the unit support member main body 3A, and the fitting hole forming portions of the upper and lower portions are combined with each other, thereby forming a fitting hole that extends along the entire circumference. . The outer ring 4b (FIG. 6) is fitted into this fitting hole.

As shown in FIGS. 6 and 7, each mounting shaft portion 16b is formed with a female thread extending in the radial direction, and a bolt 23 screwed into the female thread is provided. A disk-shaped pressing member 24 is interposed on the end surface of the inner ring 4a, and a bolt 23 screwed into the female thread portion applies a pressing force to the end surface of the inner ring 4a, thereby preloading each rotation-allowing support member 4. giving. Thereby, the rigidity of each rotation-permitting support component 4 can be increased. The rolling bearing of the rotation-permitting support component 4 may be an angular ball bearing or a four-point contact ball bearing instead of the tapered roller bearing. Also in that case, preload can be applied in the same manner as described above.

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

As shown in FIG. 2 , the arm portion 17 is a portion that acts as a point of action for applying an auxiliary steering force to the outer ring 19 of the hub bearing 15 and integrally protrudes from a portion of the outer circumference of the outer ring 16 . The arm portion 17 is rotatably connected to the direct-acting output portion 25 a of the steering actuator 5 via the joint portion 8 . As a result, the direct-acting output portion 25a of the steering actuator 5 advances and retreats, so that the hub unit main body 2 rotates about the turning axis A (FIG. 1), that is, is assisted to be steered.

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

A first sealing means is provided between a flat portion 35 of the annular portion 16a which is perpendicular to the steering axis A and a flat portion 36 of the unit support member 3 which faces the flat portion 35 via a gap δ1. 33 are arranged respectively. Each flat portion 35 of the annular portion 16a is formed with an annular groove 35a around the turning axis A, and a first sealing means 33 is fitted in each annular groove 35a. As the first sealing means 33, an elastic member such as a slidable O-ring is used. Lubricant is applied to the elastic member fitted in the annular groove 35a. The elastic member fitted in the annular groove 35a is crushed by the flat portion 36 of the unit support member 3 and elastically deformed, thereby sealing the gap δ1. Instead of forming the annular groove 35a on the flat portion 35 of the annular portion 16a, an annular groove is formed on the flat portion 36 of the unit support member 3 so that the annular groove 35a is formed on the flat portion 36 of the unit support member 3. A 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 support 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 support member 3 and an axial base end portion of the cylindrical portion 34a. and a bottom portion 34b. The bottom surface portion 34b is formed concentrically with a disc portion 34ba radially extending from the axial base end portion of the cylindrical portion 34a and a large-diameter cylindrical portion 34a protruding axially from the vicinity of the center of the disc portion 34ba. It has a small diameter cylindrical portion 34bb and a bottom portion 34bc that covers the axial base end of the small diameter cylindrical portion 34bb.

As for the second sealing means 34 on the upper side shown in FIG. 7(a), the large-diameter cylindrical portion 34a is fitted and fixed in the fitting hole 3Ac of the unit support member main body 3A, for example. Regarding the second sealing means 34 (FIG. 1) on the lower side, a large-diameter cylindrical portion 34a is, for example, fitted and fixed to the inner peripheral surface of the unit supporting member assembly 3B (FIG. 1) of a cylindrical member. be. 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 disc portion 34ba and a large-diameter cylindrical portion 34a. Further, the second sealing means 34 prevents interference with the brake rotor 21a by providing a small-diameter cylindrical portion 34bb and a disc portion 34ba.

<Steering Actuator 5>
As shown in FIG. 3, the steering actuator 5 has an actuator body 7 that rotates the hub unit body 2 around the turning axis A (FIG. 1).
As shown in FIG. 2, the actuator main body 7 includes a motor 26, a speed reducer 27 that reduces the rotation of the motor 26, and converts the forward and reverse rotation output of the speed reducer 27 into reciprocating linear motion of a linear motion output section 25a. A linear motion mechanism 25 is provided. 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, a gear train, or the like, 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 coupled to the motor shaft of the motor 26, and the linear motion mechanism 25 is provided with a driven pulley 27b. 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. As shown in FIG.

The linear motion mechanism 25 can use a feed screw mechanism such as a slide screw or a ball screw, or a rack and pinion mechanism, etc. In this example, a feed screw mechanism using a trapezoidal slide screw is used. Since the direct-acting mechanism 25 includes a feed screw mechanism using the sliding screw of the trapezoidal screw, the effect of preventing reverse input from the tire 9b can be enhanced. The actuator main body 7 including the motor 26, the speed reducer 27, and the linear motion mechanism 25 is assembled as a sub-assembly and detachably attached to the case 6b with bolts or the like. A mechanism is also possible in which the driving force of the motor 26 is directly transmitted to the direct acting mechanism 25 without using a speed reducer.

As a part of the unit support member 3, the case 6b is formed integrally with the unit support member main body 3A. The case 6b is formed in a cylindrical shape with a bottom, and is provided with a motor accommodating portion that supports the motor 26 and a linear motion mechanism accommodating portion that supports the linear motion mechanism 25 . A fitting hole for supporting the motor 26 at a predetermined position inside the case is formed in the motor accommodating portion. 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 retreat, and the like are formed in the linear motion mechanism accommodating portion.

As shown in FIG. 3, the unit support member main body 3A includes the case 6b, a shock absorber mounting portion 6c that serves as a shock absorber mounting portion, and a steering device connecting portion 6d that serves as a connecting portion for the steering device 11 (FIG. 2). have. The shock absorber attachment portion 6c and the steering device coupling portion 6d are also formed integrally with the unit support member main body 3A. A shock absorber attachment portion 6c is formed so as to protrude from the upper portion of the outer surface portion of the unit support member main body 3A. A steering device coupling portion 6d is formed so as to protrude from the side portion of the outer surface portion of the unit support member main body 3A.

<Effect>
According to the steering function-equipped hub unit 1 described above, the hub unit body 2 including the hub bearings 15 that support the wheels 9 can be freely rotated around the turning axis A by driving the actuator body 7 . . This rotation is added to the steering by the steering wheel operation of the driver, that is, to the rotation of the knuckle 6 about the kingpin axis by the steering device 11, and is performed as an auxiliary steering, and independent steering of one wheel can be performed. . The toe angle between the left and right wheels 9, 9 can be arbitrarily changed by making the angles of the auxiliary steering of the left and right wheels 9, 9 different.

Therefore, the hub unit 1 with a steering function may be used for both steered wheels such as the front wheels and non-steered wheels such as the rear wheels. When used as a steered wheel, by being installed on a member whose direction can be changed by the steering device 11, in addition to the steering by the driver's steering operation, the left and right wheels are independent or interlocked with the left and right wheels. It is a mechanism that makes a minute change in the angle of As for the angle of the auxiliary steering, a slight angle is sufficient to improve the motion performance of the vehicle and to improve the stability and safety of the vehicle. The angle of the auxiliary steering is controlled by the steering actuator 5 .

Also, during turning, the steering angle difference between the left and right wheels can be changed according to the running speed. For example, the steering geometry can be changed during driving, such as parallel geometry for high-speed cornering and Ackermann geometry for low-speed cornering. Since the wheel angle can be arbitrarily changed during running in this manner, the motion performance of the vehicle can be improved, and the vehicle can run stably and safely. By appropriately changing the steering angle of the left and right steered wheels during cornering, it is possible to reduce the turning radius of the vehicle and improve the tight turning performance.
Furthermore, even when driving in a straight line, by adjusting the amount of toe angle according to each situation, it is possible to make adjustments such as reducing running resistance at low speeds without deteriorating fuel efficiency and ensuring running stability at high speeds.

When the hub unit 1 with steering function is applied to the rear wheels 9R, which are the non-steered wheels, when the steering angle is set to the same phase as the front wheels 9F during turning, the yaw generated during steering is suppressed and the stability of the vehicle is enhanced. be able to. Driving stability can be ensured by adjusting the toe angle independently on the left and right even when driving in a straight line.
However, the mechanism for steering around the steering axis A in the wheel 9a must be waterproof and dustproof.

In this hub unit 1 with a steering function, the first sealing means 33 is arranged between the outer ring 16 of the hub unit body 2 and the unit support member 3 , and the second sealing means 33 covering the rotation-allowing support member 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 may be employed as the first sealing means 33 . Since it is sufficient for the second sealing means 34 to cover the rotation-permitting support component 4, the sealing means can be made compact by using a thin lid-shaped sealing means. As a result, it is possible to prevent water, foreign matter, and the like from entering the periphery of the steering shaft while ensuring the rigidity of the steering shaft portion 16b. Moreover, since the structures of the first and second sealing means 33 and 34 can be simplified, the overall size and weight of the 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 portion 34b connected to the axial base end portion of the cylindrical portion 34a. be. Therefore, the second sealing means 34 can be easily mass-produced by using a mold or the like, and the cost can be reduced. can be prevented.

A first sealing means is provided between a flat portion 35 of the annular portion 16a which is perpendicular to the steering axis A and a flat portion 36 of the unit support member 3 which faces the flat portion 35 via a gap δ1. 33, a simple and compact structure can be adopted as the first sealing means 33. As a result, the respective cross sections of the steering shaft portion 16b and the rotation-permitting support component 4 can be made to have desired sizes, and the rigidity of the steering shaft portion 16b and the rotation-permitting support component 4 can be easily ensured. . Further, since the first sealing means 33 is arranged between the flat portion 35 of the annular portion 16a and the flat portion 36 of the unit support member 3, the outer peripheral surface of the turning shaft portion 16b and the unit support member 3 Compared to the later-described configuration (FIG. 8) in which the first sealing means 33 is arranged between a part of the inner peripheral surface of becomes.

Since the rotation-permitting support part 4 is located inside the wheel 9a of the wheel 9, the distance between the steering axis A and the ground contact surface of the wheel 9 can be reduced or eliminated. 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 same reference numerals are given to the parts corresponding to the items previously described in each embodiment, and duplicate descriptions are omitted. When only a portion of the configuration is described, the other portions of the configuration are the same as those previously described unless otherwise specified. The same configuration has the same effect. It is possible not only to combine the parts specifically described in each embodiment, but also to partially combine the embodiments if there is no particular problem with the combination.

[Second embodiment]
FIG. 8(a) is an enlarged cross-sectional view of the periphery of a rotation-allowing support component 4 in a hub unit 1 with a steering function according to a second embodiment of the invention, and FIG. 8(b) is an enlarged cross-sectional view of FIG. 8(a). 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 in the first embodiment.

In the hub unit 1 with a steering function, the outer peripheral surfaces of the upper and lower steering shaft portions 16b on the base end side and the part of the unit support member 3 facing the outer peripheral surfaces of the respective steering shaft portions 16b with a gap δ2 therebetween. A first sealing means 33 is arranged between the inner peripheral surface. As for the upper first sealing means 33, the upper supporting portion 3Ab of the unit supporting member main body 3A corresponds to "a part of the unit supporting member 3". The unit support member assembly 3B (FIG. 1) corresponds to "a part of the unit support member 3".

An annular groove 37 is formed in the outer peripheral surface of each steering shaft portion 16b on the base end side, and a 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 support member 3 and elastically deformed, thereby sealing the gap δ2.

Also in this configuration, since a simple and compact structure can be adopted as the first sealing means 33, the cross sections of the steering shaft portion 16b and the rotation-allowing support member 4 can be made to desired sizes, and the steering shafts can be Rigidity of the portion 16b and the rotation-permitting support component 4 can be easily ensured.
Instead of the configuration in which the annular groove 37 is formed on the outer peripheral surface of the steering shaft portion 16b, an annular groove is formed in a part of the unit support member 3 so that the annular groove formed in the unit support member 3 has a second groove. One sealing means 33 may be fitted.

[Third Embodiment]
As shown in FIG. 9, the outer peripheral surface of the base end side of the upper and lower steering shaft portions 16b and the inner peripheral surface of a portion of the unit support member 3 facing the outer peripheral surface of each steering shaft portion 16b with a gap therebetween. A first sealing means 33 consisting of an oil seal may be arranged between .

<About application to non-steering wheels>
The hub unit 1 with steering function 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 in an underbody frame component 6R serving as a wheel bearing installation portion of a suspension device 12R that supports a rear wheel 9R, and used for rear-wheel steering.
Alternatively, as shown in FIG. 12, the hub unit 1 with steering function may be used for left and right front wheels 9F, 9F as steered wheels and left and right rear wheels 9R, 9R as non-steered wheels.

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

The host controller 32 is a host controller of the steering controller 30. As the host controller 32, for example, a vehicle control unit (VCU) for controlling the entire vehicle is applied. The actuator drive control section 31 drives and controls the steering actuator 5 by outputting a current corresponding to the current command signal input from the steering control section 30 . The actuator drive control section 31 controls power supplied to the coils of the motor 26 . The actuator drive control unit 31, for example, constitutes a half-bridge circuit using switch elements (not shown), and performs PWM control for determining the voltage applied to the motor according to the ON-OFF duty ratio of the switch elements. As a result, the angle of the wheels can be slightly changed in addition to the steering by the steering wheel operation of the driver. Even when driving in a straight line, the amount of toe angle can be adjusted according to each situation.

The steering system may operate the steering actuators 5, 5 according to a command from an automatic driving device or a driving support device (not shown) instead of the steering wheel operation by the driver.
As mentioned above, although the form for implementing this invention was demonstrated based on embodiment, embodiment disclosed this time is an illustration and is not restrictive at all points. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

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

Claims (7)

a hub unit body having a hub bearing that supports a wheel and an outer ring provided on the outer peripheral surface of the fixed ring of the hub bearing;
a unit support member provided on a suspension frame part of a suspension system for supporting the hub unit body rotatably around a steering shaft extending in the vertical direction;
a rotation-allowing support member that allows the hub unit main body to rotate about the steering axis with respect to the unit support member;
a steering actuator that rotationally drives the hub unit body about the turning axis;
a first sealing means disposed between the outer ring and the unit support member;
a second sealing means covering the rotation-permitting support component ;
The outer ring includes an annular portion fixed to the outer peripheral surface of the outer ring, which is the fixed ring, and a trunnion shaft-shaped steered shaft portion projecting vertically from the outer periphery of the annular portion and mounting the rotation-allowing support parts respectively. and
The first sealing means is arranged between a plane portion of the annular portion perpendicular to the turning axis and a plane portion of the unit support member facing each other with a gap between the plane portions. hub unit with steering function. a hub unit body having a hub bearing that supports a wheel and an outer ring provided on the outer peripheral surface of the fixed ring of the hub bearing;
a unit support member provided on a suspension frame part of a suspension system for supporting the hub unit body rotatably around a steering shaft extending in the vertical direction;
a rotation-allowing support member that allows the hub unit main body to rotate about the steering axis with respect to the unit support member;
a steering actuator that rotationally drives the hub unit body about the turning axis;
a first sealing means disposed between the outer ring and the unit support member;
a second sealing means covering the rotation-permitting support component;
The outer ring includes an annular portion fixed to the outer peripheral surface of the outer ring, which is the stationary ring, and a trunnion shaft-like roller protruding vertically from the outer periphery of the annular portion to which the rotation-allowing support parts are mounted. and a rudder shaft,
The first sealing means is provided between the outer peripheral surfaces of the upper and lower steered shaft portions and the inner peripheral surface of a portion of the unit support member facing the outer peripheral surfaces of the steered shaft portions with a gap therebetween. Hub unit with steering function where 3. 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 steering axis, and the outer ring of the rolling bearing is the unit supporting member. is installed in a fitting hole formed in the inner ring is supported by the outer ring,
The second sealing means has a steering function hub having a cylindrical portion fixed to the fitting hole of the unit support member and a bottom portion connected to an axial base end portion of the cylindrical portion and covering the rolling bearing. unit. 4. The hub unit with steering function according to claim 1, wherein a slidable elastic member is used as said first sealing means. 5. The hub unit with steering function according to any one of claims 1 to 4 , wherein said rotation-allowing support component is arranged inside said wheel. A steering system comprising the hub unit with a steering function according to any one of claims 1 to 5 and a control device for controlling a steering actuator of the hub unit with a steering function, wherein the control device is a steering control section that 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 section to drive and control the steering actuator. a steering system having an actuator drive control; A vehicle in which one or both of front wheels and rear wheels are supported using the hub unit with a steering function according to any one of claims 1 to 5 .

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