JP2019006225A - Hub unit with auxiliary steering function and vehicle - Google Patents

Abstract

To provide a simple and firm hub unit with auxiliary steering function by which auxiliary steering depending a travel state can be performed for left and right wheels independently, maneuverability of a vehicle can be improved, and improvements in travel stability/safety and fuel consumption can be achieved, and a vehicle.SOLUTION: The hub unit comprises: a hub unit body 4 having a hub bearing 3; a unit support member 5 which is installed onto a vehicle body via a suspension device, and so supports the hub unit body 4 at vertical two points as to be rotatable around an auxiliary steering axis which extends in a vertical direction; and an auxiliary steering actuator 6 which is installed onto the unit support member 5 and rotates the hub unit body 4 around the auxiliary steering axis. The auxiliary steering actuator 6 includes a motor 27 and a direct-acting mechanism 29, and a direct-acting output part is connected to the hub unit body 4. The direct-acting mechanism 29 is configured from, for example, a feed screw mechanism having a self-locking function for a trapezoidal screw or the like.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hub unit with an auxiliary turning function and a vehicle having a function of performing auxiliary turning such as turning and rear wheel turning for turning by a steering device, and stability and safety of running performance. Related to improved 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 the left and right wheels by tie rods. Therefore, the turning angle of the left and right wheels due to the movement of the handle is determined by the initial setting.
Vehicle geometry includes (1) “Parallel geometry” where the left and right wheels have the same turning angle, and (2) The turning inner wheel tire angle is cut larger than the turning outer wheel tire angle in order to have one turning center. Ackermann geometry is known.

The geometry of the vehicle affects the stability and safety of running.
For example, Patent Documents 1 and 2 have been proposed regarding a mechanism in which the steering geometry is variable in accordance with the traveling state. In Patent Literature 1, the steering geometry is changed by relatively changing the knuckle arm and the joint position. In Patent Document 2, two motors are used, and both the toe angle and the camber angle can be tilted to an arbitrary angle. Patent Document 3 proposes a four-wheel independent steering mechanism.

  As the rear wheel steering device, various types of configurations that rotate the left and right rear wheels in conjunction with each other are proposed as an auxiliary to steering with the front wheels (for example, Patent Document 4).

JP 2009-226972 A German Patent Application Publication No. 10201206337 JP 2014-061744 A JP-A-2006-147513

  Ackerman geometry is a difference in rudder angle between the left and right wheels so that each wheel turns around a common point in order to smoothly turn the wheels when turning 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 that the wheels generate a cornering force in a direction that balances with the centrifugal force. Therefore, the parallel geometry is preferable to the Ackermann geometry.

  As described above, since a general vehicle steering device is mechanically connected to a wheel, generally only a single fixed steering geometry can be taken, and an intermediate between the Ackermann geometry and the parallel geometry. Often set to static geometry. However, in this case, the difference in steering angle between the left and right wheels is insufficient in the low speed range, the steering angle of the outer wheel is excessive, and the steering angle of the inner wheel is excessive in the high speed range. If there is an unnecessary bias in the tire lateral force distribution between the inner and outer wheels in this way, it causes deterioration of fuel consumption due to worsening of running resistance and early tire wear, and smooth cornering due to the inefficient use of the inner and outer wheels. There is a problem that is damaged.

According to the proposals in Patent Documents 1 and 2, the steering geometry can be changed, but there is the following problem.
In Patent Document 1, as described above, the steering geometry is changed by relatively changing the knuckle arm and the joint position. However, a motor actuator that obtains a large force enough to change the vehicle geometry in such a portion. It is very difficult to prepare due to space constraints. In addition, the change in the tire angle due to the change at this position is small, and in order to obtain a large effect, it is necessary to change it greatly, that is, to move it greatly.
In Patent Document 2, since two motors are used, the cost increases due to the increase in the number of motors and the control becomes complicated.
Patent Document 3 can be applied only to vehicles with four-wheel independent steering, and because the hub bearing is cantilevered with respect to the steering shaft, the rigidity is lowered, and the steering geometry is caused by the occurrence of excessive traveling G. It may change.
Moreover, when a reduction gear is provided on the steered shaft, a large amount of power is required. For this reason, although a motor is enlarged, when a motor is enlarged, it will become difficult to arrange | position the whole to the inner peripheral part of a wheel. Moreover, when a reduction gear with a large reduction ratio is provided, the responsiveness deteriorates.

  The conventional mechanism having an auxiliary turning function as described above has a complicated structure because it aims to arbitrarily change the toe angle and the camber angle of the tire in the vehicle. Moreover, it is difficult to ensure rigidity, and it is necessary to increase the size and weight in order to ensure rigidity.

  On the other hand, as described above, various types of rear wheel steering devices have been proposed in which the left and right rear wheels are interlocked and steered, but the left and right rear wheels can be independently steered and the toe angle can be adjusted. Many of the configurations are not configured, and in the case of a configuration that can be independently steered, the configuration is complicated or the configuration that is not satisfactory in terms of rigidity.

Further, in both the addition of the steered wheels and the rear wheel steer, it is necessary to prevent the stability of the assist steering from being hindered by the reverse input from the tire to the actuator for the assist steering.
Also, in both the addition of turning of the steered wheels and the rear wheel turning, the responsiveness for setting an appropriate turning angle for the tire is important in accordance with the traveling situation, but in all the conventional examples, The responsiveness is not fully considered.

  The object of the present invention is that the auxiliary steering according to the driving situation can be performed independently for the left and right wheels, improving the motion performance of the vehicle, improving the stability and safety of driving, and improving the fuel efficiency. Another object of the present invention is to provide a hub unit with an auxiliary turning function and a vehicle that have a simple structure and are robust.

  A hub unit with an auxiliary turning function according to the present invention includes a hub unit main body having a hub bearing for supporting wheels, and an auxiliary turning shaft center that is installed in a vehicle body via a suspension device and extends in the vertical direction. A unit support member that is supported at two upper and lower positions via a rotation-supporting support component, and an auxiliary rolling device that is installed on the unit support member and rotates the hub unit body about the auxiliary turning axis. A steering actuator, and the auxiliary steering actuator includes a motor and a linear motion mechanism that converts the rotational output of the motor into a linear motion, and the linear motion output portion of the linear motion mechanism is the hub unit. It is rotatably connected to the main body.

According to this configuration, the hub bearing supporting the wheel can be freely rotated around the auxiliary turning axis by driving the poem together with the hub unit body, and independent turning of one wheel can be performed. The toe angle of the tire can be arbitrarily changed according to the traveling state of the vehicle. Therefore, it may be used for any of the steered wheels such as front wheels and the non-steered wheels such as rear wheels. When used for steered wheels, it is installed on a member whose direction is changed by the steering device, so that it can be added to the steer by the steering operation of the driver, and the left and right wheels are individually or linked to the left and right wheels. It is a mechanism that makes an angle change.
While traveling, the tire angle can be arbitrarily changed independently for the left and right wheels, so that it is possible to improve the motion performance of the vehicle and travel stably and safely. For example, the steering geometry can be changed while the vehicle is running, such as a parallel geometry for turning at high speeds and an Ackermann geometry for low speeds. It is also possible to improve fuel efficiency by setting an appropriate tire angle.
When this hub unit with an auxiliary turning function is used as a rear wheel that is a non-steering wheel, the minimum turning radius during low-speed traveling can be reduced.
In addition, this hub unit with an auxiliary steering function is supported at both upper and lower portions by means of rotation-supporting support parts, so that both ends are supported and rigidity is ensured. It is.
Since the auxiliary steering actuator is composed of a motor and a linear motion mechanism that converts the rotation output of this motor into linear motion, it can be driven for auxiliary steering by motor drive with a simple configuration, and control is also possible. Easy.
In this way, auxiliary steering according to the driving situation can be performed independently on the left and right wheels, improving the movement performance of the vehicle, improving driving stability and safety and improving fuel efficiency, And it becomes a solid composition.

In the hub unit with an auxiliary turning function of the present invention, the auxiliary turning actuator may further include a speed reducer that decelerates the rotation of the motor. The speed reducer may be a winding transmission mechanism, and the linear motion mechanism may be a sliding screw feed screw mechanism. The winding transmission mechanism may be a belt transmission mechanism or a chain transmission mechanism. The auxiliary steering actuator may be a mechanism that directly transmits a driving force from a motor to a linear motion mechanism without using a reduction gear.
When a slide screw is used as the linear motion mechanism, reverse input from the tire can be prevented. Further, when the speed reducer is a winding transmission mechanism, the speed reducer has a simple configuration. For example, a trapezoidal screw or a triangular screw can be used as the sliding screw.

In the hub unit with an auxiliary turning function of the present invention, the speed reducer may be a gear train, and the linear motion mechanism may be a sliding screw feed screw mechanism.
When the reduction gear is a gear train, the drive transmission is highly rigid and highly responsive.

The slide screw feed screw mechanism constituting the linear motion mechanism is preferably of a type having a self-locking function.
If a slide screw with a self-locking function is used, reverse input from the tire is prevented, and even if the motor fails, the vehicle does not wobble due to the self-locking function and the vehicle can be moved to a safe place by operating the steering wheel. Safety can be ensured. In addition, if the linear motion mechanism has a self-locking function, it can continue to have a certain angle of auxiliary steering when it does not perform auxiliary steering or when traveling at high speed, etc. Is unnecessary and the motor power can be reduced.

In the vehicle of the present invention, either or both of the front wheels and the rear wheels are supported using the hub unit with an auxiliary turning function having any one of the above-described configurations of the present invention.
Therefore, each effect mentioned above about the hub unit with an auxiliary turning function of this invention is acquired. The front wheels are generally steered wheels, but when the hub unit with an auxiliary steer function of the present invention is applied to the steered wheels, it is effective for adjusting the toe angle during traveling. The rear wheels are generally non-steered wheels, but when applied to non-steered wheels, the minimum turning radius during low-speed traveling can be reduced by slightly turning the non-steered wheels.

  A hub unit with an auxiliary turning function according to the present invention includes a hub unit body having a hub bearing for supporting wheels, and an auxiliary turning shaft center that is installed in a vehicle body via a suspension device and extends in the vertical direction. A unit support member that is supported at two upper and lower positions via a rotation-supporting support component, and an auxiliary rolling device that is installed on the unit support member and rotates the hub unit body about the auxiliary turning axis. A steering actuator, and the auxiliary steering actuator includes a motor and a linear motion mechanism that converts the rotational output of the motor into a linear motion, and the linear motion output portion of the linear motion mechanism is the hub unit. Since it is connected to the main body so as to rotate freely, auxiliary steering according to the driving situation can be performed independently for the left and right wheels, improving the movement performance of the vehicle and improving the stability and safety of driving. And it is possible to improve the fuel consumption, also the configuration is simple, and robust.

  In the vehicle of the present invention, either or both of the front wheels and the rear wheels are supported by using the hub unit with an auxiliary turning function, so that auxiliary steering according to the traveling state can be performed independently on the left and right wheels, It has excellent performance, can improve driving stability and safety, and can improve fuel efficiency. The hub unit with an auxiliary steering function is simple and robust.

It is a longitudinal cross-sectional view which shows the structure of the hub unit with an auxiliary | assistant steering function which concerns on 1st Embodiment of this invention, and its periphery. It is a horizontal sectional view showing composition of the hub unit with the auxiliary turning function and its surroundings. It is a longitudinal cross-sectional view of the hub unit with an auxiliary turning function. It is an external appearance perspective view of the hub unit with the auxiliary turning function. It is a left view of the hub unit with the auxiliary turning function. It is a horizontal sectional view showing the main turning neutral state of the hub unit with the auxiliary turning function. It is a horizontal sectional view showing the main turning non-neutral state of the hub unit with the auxiliary turning function. It is a longitudinal cross-sectional view which shows the structure of the hub unit with an auxiliary | assistant steering function which concerns on 2nd Embodiment of this invention, and its periphery. It is a horizontal sectional view showing composition of the hub unit with the auxiliary turning function and its surroundings. It is a longitudinal cross-sectional view of the hub unit with an auxiliary turning function. It is an external appearance perspective view of the hub unit with the auxiliary turning function. It is a left view of the hub unit with the auxiliary turning function. It is a horizontal sectional view showing a specific example of an actuator for auxiliary steering used in the first and second embodiments. It is a horizontal sectional view showing other specific examples of an auxiliary steering actuator used in the first and second embodiments. It is a schematic plan view of an example of a vehicle to which the hub unit with an auxiliary turning function of each embodiment is applied.

  A first embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the hub unit 1 with an auxiliary turning function includes a hub unit body 4 having a hub bearing 3 for supporting a wheel 2, a unit support member 5, and an auxiliary turning actuator 6. The hub unit main body 4 is supported by the unit support member 5 via the rotation-permitting support parts 7 and 7 at two locations in the upper and lower directions so as to be rotatable around the auxiliary turning axis A extending in the vertical direction. The auxiliary turning axis A is an axis different from the rotation axis O of the wheel 2 and is different from the kingpin axis K that performs main turning. The wheel 2 includes a wheel 8 and a tire 9.

The auxiliary steering function with the hub unit 1 is steered wheels in this embodiment, as specifically shown in FIG. 15, the right and left wheels individually added to the steered by the front wheels 2 _F steering system 25 of the vehicle 10 It is installed in the knuckle 22 as a mechanism for turning a small angle. The steering device 25 is a device that steers the wheels 2 _F and 2 _F in accordance with an operation of a handle (not shown). The auxiliary steering function with the hub unit 1, In addition, may be used as a mechanism for steering the rear wheels 2 _R as an adjunct to the front wheel steering.

  In FIG. 1, the unit support member 5 is attached to the knuckle 22 of the suspension device 21 installed in the vehicle body 10A (see FIG. 15). The unit support member 5 may be provided integrally with the knuckle 22, that is, as a part of the knuckle 22. The suspension device 21 is of a double wishbone type in this example, and has an upper arm 23 and a lower arm 24 connected via a shock absorber (not shown), and between the upper arm 23 and the lower arm 24. The knuckle 22 is installed so as to be rotatable around the inclined kingpin axis K. The suspension device 21 can employ other various types such as an independent suspension type. As shown in FIG. 2, the knuckle 22 has a steering device connecting portion 22 a that protrudes in an arm shape and is rotatably connected to a tie rod 26 of the steering device 25.

  As shown in FIG. 3, the hub bearing 3 includes an inner ring 12, an outer ring 11, and rolling elements 13 such as balls interposed between the inner and outer rings, and serves to connect the vehicle body side member and the wheel 2. doing. In the illustrated example, the hub bearing 3 is an angular ball bearing in which the outer ring 11 is a fixed ring, the inner ring 12 is a rotating ring, and the rolling elements 13 are double-rowed. The inner ring 12 includes a hub ring portion 12a having a hub flange 12aa and constituting a raceway surface on the outboard side, and an inner ring portion 12b constituting a raceway surface on the inboard side. As shown in FIG. 2, the wheel 8 of the wheel 2 is bolted to the hub flange 12aa so as to overlap the brake rotor 14a. The inner ring 12 rotates around the rotation axis O.

  The brake rotor 14a constitutes the brake 14 with the brake caliper 14b. The brake caliper 14b is attached to two upper and lower brake caliper attachment portions 36 formed integrally with the outer ring 11 (see FIG. 3) shown in FIGS.

In FIG. 3, the hub unit main body 4 is a portion that rotates around the auxiliary turning axis A in the hub unit 1 with the auxiliary turning function, and includes the hub bearing 3 and the rotation side component 15 of the rotation permissible support component 7. And an auxiliary turning force receiving portion 18 (see FIGS. 2 and 4).
In this embodiment, the rotation-permissible support component 7 is formed of a spherical plain bearing, and includes a rotation-side component 15 having a concave spherical seat 15a and a spherical portion 16a that is rotatably fitted in the concave spherical seat 15a in any direction. It is mainly comprised by the stationary side component 16 which has at the front-end | tip of 16b. The concave spherical seat 15a is covered with a bellows-like flexible boot 17 covering the outer periphery of the shaft portion 16b.
The rotation-side parts 15 of the upper and lower rotation-allowing support parts 7 are bottomed cylindrical mounting seats 19, 19 provided as protrusions at two locations above and below the outer peripheral surface of the outer ring 11 of the hub bearing 3. Are attached in a fitted state.
The stationary-side component 16 of the rotation-permissible support component 7 is attached to the unit support member 5 so that the preload adjustment of the rotation-permissible support component 7 can be performed by the preload adjusting means 48. Specifically, the unit support member 5 is a support member main body 5a fixed to the knuckle 22, and a support member divided body 5b whose position can be adjusted in the direction along the auxiliary turning axis A with respect to the support member main body 5a. The support member divided body 5 b can be adjusted in position by tightening rotation of the adjustment bolt 49. The pressure adjusting means 48 is constituted by this divided structure and the adjusting bolt 49.
In this specification, the “spherical plain bearing” includes a spherical bush and a pivot bearing.

  In this embodiment, as described above, the mounting seat 19 is formed integrally with the outer ring 11 of the hub bearing 3 and the rotation-side component 15 of the rotation-permitting support component 7 is directly attached to the outer ring 11. A mounting part (not shown) such as a shaft box may be provided on the outer periphery of the outer ring 11, and the rotation side part 15 of the rotation permissible support part 7 may be mounted on this mounting part.

As shown in FIG. 1, the auxiliary turning axis A of the hub unit body 4 extends in the vertical direction, but is a direction different from the kingpin axis K, for example, the vertical direction. In this embodiment, the auxiliary steering axis A is the intersection position P _K between the extension and the road surface S of the kingpin axis K, the intersection position P _A of the extension line and the road surface S of the auxiliary steering axis A is Both are designed to be located within the tire ground contact surface 9a. Furthermore, it is optimal that these intersection positions P _K and P _A coincide with each other because tire slip is minimized. The “tire contact surface” refers to a place where the tire 9 is in contact with the road surface S in a state where one person (corresponding to 55 kg) is in the driver's seat.

  The auxiliary turning force receiving portion 18 shown in FIG. 2 and FIG. 4 is a portion that serves as an action point for applying auxiliary turning force to the outer ring 11 of the hub bearing 3, and is a part of the outer periphery of the outer ring 11 of the hub bearing 3. It is provided as an arm part protruding integrally. The auxiliary turning force receiving portion 18 is rotatably connected to the linear motion output portion 6a of the auxiliary turning actuator 6 via a joint 57 as will be described later with reference to FIG. Thereby, the hub unit main body 4 rotates around the auxiliary axis A, that is, is auxiliary-steered, by moving the linear output part 6a of the auxiliary-steering actuator 6 forward and backward.

The auxiliary steering actuator 6 includes a motor 27 (see FIG. 3), a speed reducer 28 in FIG. 2 that decelerates the rotation of the motor 27, and a forward / reverse rotation output of the speed reducer 28 as the linear motion output unit 6a. And a linear motion mechanism 29 for converting into a reciprocating linear motion. The motor 27 is, for example, a permanent magnet type synchronous motor, but may be a DC motor or an induction motor.
The speed reducer 28 can use a wrapping type transmission mechanism such as a belt transmission mechanism or a gear train, and a belt transmission mechanism is used in the example of FIG.
As the linear motion mechanism 29, a feed screw mechanism such as a slide screw or a ball screw or a rack and pinion mechanism can be used. In this example, a feed screw mechanism using a trapezoidal screw slide screw is used.
A mechanism that directly transmits the driving force of the motor 27 to the linear motion mechanism 29 without using a reduction gear is also possible.

  The auxiliary turning angle θ (see FIGS. 6 and 7) of the hub unit body 4 with respect to the knuckle 22 is regulated by a stopper 35. FIG. 6 shows a state in which the main turning is in a straight traveling state and the auxiliary turning is performed inside, and FIG. 7 shows a state in which the main turning is directed to the left side and the auxiliary turning is performed inside. . The stopper 35 is provided, for example, on the surface of the unit support member 5 that faces the hub unit body 4 in the axial direction, for example, the surface that faces the end surface of the outer ring 11 of the hub bearing 3, and the outer ring end surface abuts on the surface. The auxiliary steering angle θ of the hub unit body 4 is restricted. The allowable range of the auxiliary steerable angle of the hub unit body 4 may be a slight angle, and the allowable range of the auxiliary steerable angle by the stopper 35 is, for example, ± 5 degrees or less.

  In this embodiment, a mounting seat 19 (FIGS. 3 and 4) for attaching the rotation-allowing support component 7 to the outer ring 11 of the hub bearing 3 and the auxiliary turning force receiving portion 18 (FIGS. 2 and 4). And the brake caliper mounting portion 36 are integrally formed. The mounting seat portion 19, the auxiliary turning force receiving portion 18, and the brake caliper mounting portion 36 are all provided in the hub unit body 4. In the case where the outer ring 11 is provided with a mounting part (not shown) such as the axle box, it may be provided on the mounting part.

The operation and action of the above configuration will be described. In the hub unit 1 with an auxiliary turning function, a hub unit body 4 having a hub bearing 3 and a brake caliper 14b (see FIG. 2) is connected to a unit support member 5 provided on the knuckle 22 in FIG. The hub unit body 4 is rotatable by applying a force to the arm-shaped auxiliary steering force receiving portion 18 (FIG. 2) that is rotatable about the center A and serves as an action point. The hub unit main body 4 is configured to move the linear motion output portion 6a of the auxiliary steering actuator 6 installed on the unit support member 5 forward and backward by driving the motor 27, so that the auxiliary steering force coupled to the linear motion output portion 6a is achieved. It is rotated via the receiving part 18.
This rotation is performed as an auxiliary steering in addition to the steering by the driver's steering operation, that is, in addition to the rotation of the knuckle 22 around the kingpin axis K (FIG. 1) by the steering device 25. One wheel can be independently steered. By changing the angle of the auxiliary steering of the left and right wheels 2 and 2, the toe angle between the left and right wheels 2 and 2 can be arbitrarily changed.

Since the tire angle can be arbitrarily changed independently of the left and right wheels during traveling according to the traveling conditions of the vehicle 10, the motion performance of the vehicle 10 can be improved and the vehicle can travel stably and safely. It is also possible to improve fuel efficiency by setting an appropriate tire angle.
When this auxiliary steering function-equipped hub unit 1 is used for the rear wheel 2 _R (FIG. 15), which is a non-steered wheel, it is possible to reduce the minimum turning radius during low-speed traveling.
In addition, the hub unit 1 with an auxiliary turning function is supported at both ends by the rotation-allowing support parts 7 and 7 at the two upper and lower portions, so that the rigidity is secured at both ends. And simple in configuration.
In this way, with a simple structure and securing rigidity, auxiliary steering according to the driving situation can be performed independently on the left and right wheels, and the toe angle of the wheel 2 can be arbitrarily changed, and the steering geometry Therefore, it is possible to improve the motion performance of the vehicle 10, improve running stability / safety, and improve fuel efficiency.

  A control example of the steering angle difference between the left and right wheels according to the traveling speed will be described. As mentioned above, a typical vehicle steering device is mechanically connected to the wheels, so it can only take a single fixed steering geometry, and is an intermediate geometry between Ackermann and parallel geometries. It is often set to. However, in this case, the difference in steering angle between the left and right wheels is insufficient in the low speed range, the steering angle of the outer wheel is excessive, and the steering angle of the inner wheel is excessive in the high speed range. If there is an unnecessary bias in the tire lateral force distribution of the inner and outer wheels due to such steering angle problems, etc., it will cause fuel consumption deterioration due to deterioration of running resistance and early wear of the tire, and the inner and outer wheels cannot be used efficiently. , Cornering smoothness is impaired.

  Since the hub unit 1 with an auxiliary turning function of this embodiment can individually control the left and right wheels 2, the turning angle of the wheels 2, the so-called turning angle, is changed according to the vehicle speed and the turning G, and in the low speed range, the Ackermann By selecting the geometry (the difference between the steering angles of the left and right wheels so that each wheel turns around a common point) and the parallel geometry (the steering angles of the left and right wheels are the same) in the high speed range It is possible to achieve both a smooth turning performance at a low speed and a cornering performance at a high speed without increasing the resistance.

The auxiliary turning axis A may be an axis extending in the vertical direction, and may be slightly inclined. In this embodiment, however, the auxiliary turning axis A is in the vertical direction, and the camper angle changes due to auxiliary turning. It can suppress well and can further suppress the increase in running resistance. When the kingpin axis K and the auxiliary turning axis A coincide with each other, if the main unit 4 is auxiliary-steered by the kingpin axis K, the camper angle changes greatly, and the running resistance increases. However, by setting the auxiliary turning axis A separately from the kingpin axis K, a change in the camper angle due to the auxiliary turning can be suppressed, and an increase in running resistance can be suppressed.
Further, when the kingpin axis K and the auxiliary turning axis A coincide with each other, since the component parts are arranged on the vehicle body side of the hub unit main body 4, the overall size becomes large and heavy, but the auxiliary turning axis A Is in a direction different from the kingpin axis K of the suspension device 21, the size of the entire device can be suppressed and the weight can be reduced.

Furthermore, the intersecting point P _K between the extension and the road surface S of the kingpin axis K of the suspension system 21, the intersection position P _A of the extension line and the road surface of the auxiliary steering axis A are both positioned within the tire ground contact surface 9a Therefore, both main turning and auxiliary turning can be performed stably and efficiently.
When the kingpin axis K and the auxiliary steering axis A are different, if the extension of both axes and the ground contact position of the tire 9 are different, slipping occurs when both move simultaneously, which is inefficient and vehicle behavior May be disturbed. Therefore, it is desirable that the intersection position P _K between the extension line of the kingpin axis K and the road surface S and the intersection position P _A between the extension line of the auxiliary turning axis A and the road surface S are arranged in the vicinity of each other. Ideally, it is preferable that the two points P _{A and} P _K coincide with each other, so that even if the main turning and the auxiliary turning are performed at the same time, slipping does not occur and the main turning and Auxiliary steering can be performed and the vehicle can be operated stably.

  As for the angle of the auxiliary steering, a slight angle is sufficient for improving the motion performance of the vehicle and improving the stability and safety of traveling, and even if the auxiliary steering possible angle is ± 5 degrees or less, it is sufficient. The auxiliary steering angle is controlled by the auxiliary steering actuator 6 but is controlled by the stopper 35. Therefore, the hub unit 1 with the auxiliary steering function is broken due to a failure of the power supply system. In this case, it is possible to prevent a great influence from occurring. Therefore, the vehicle can be brought to a safe place by operating the steering wheel.

  In this embodiment, the rotation-allowable support component 7 is a spherical plain bearing, and can rotate in any direction around the center of the spherical surface. The center axis of the rotation-allowable support component 7 is relative to the auxiliary turning axis A. Even if it is tilted, it can be absorbed. Therefore, it can be fixed in a direction different from the auxiliary turning axis A, and the degree of freedom of the mounting position is increased and machining is facilitated. Further, in the case of a spherical plain bearing, it is possible to increase the rigidity by applying a preload between the fixed part 16 and the movable part 15 of the bearing by tightening at the time of mounting.

8 to 12 show another embodiment of the present invention. In this embodiment, instead of the rotation permissible support component 7 made of the spherical plain bearing of FIG. 1, a rotation permissible support component 7A made of a tapered roller bearing is used. As shown in FIG. 10, the rotation-allowing support component 7 </ b> A composed of the tapered roller bearing has an inner ring on the outer periphery of a trunnion shaft-shaped mounting shaft portion 19 </ b> A that is provided as a mounting portion on the outer ring 11 of the hub bearing 3. 15A is fitted, and the outer ring 16A is fitted in a fitting hole 38 provided in the unit support member 5A. With respect to the upper rotation-allowing support component 7A, a male screw portion is formed at the tip of the mounting shaft portion 19A, and the inner ring 15A is pressed in the axial direction by a nut 39 screwed into the male screw portion. With respect to the lower-side rotation-allowing support component 7A, the holding member 41 is fitted into the fitting hole 38 of the unit support member 5A, and the bolt 42 is screwed into the screw hole provided at the tip of the mounting shaft portion 19A. The end face of the outer ring 16A is pressed. By pressing with the nut 39 and the bolt 42, a preload is applied to each of the upper and lower rotation-supporting support parts 7A composed of tapered roller bearings. The unit support member 5A is divided into one unit support member main member 5Aa and a unit support member divided body 5Ab provided for each of the rotation-allowing support components 7A and 7A, and is coupled to each other by bolts 44. . The unit support member 5A is attached to the knuckle 22 with bolts 43 as shown in FIG. 8 at the unit support member divided body 5Ab. The divided configuration and the bolt 43 constitute a preload means 48A.
Note that the upper and lower rotation permissible support parts 7A and 7A may be attached to the unit support member 5A in the same structure. For example, the unit support member 5A of the upper permissible rotation support part 7A and the outer ring 11 of the hub bearing 3 in FIG. The fixing structure for the lower rotation allowable support part 7A may be applied to the lower rotation allowable support part 7A, or the lower rotation allowable support part 7A may be fixed to the upper rotation allowable support part 7A. .

As described above, even when the rotation permissible support component 7A composed of the tapered roller bearing is provided, preload can be applied to the rotation permissible support component 7A to increase the rigidity. The rotation-allowing support component 7A may be an angular ball bearing or a four-point contact ball bearing instead of the tapered roller bearing. In such a case as well, a preload can be applied in the same manner as described above.
Other configurations and effects in this embodiment are the same as those in the first embodiment, and the corresponding parts are denoted by the same reference numerals and description thereof is omitted.

  FIG. 13 shows a specific example of the auxiliary steering actuator 6. This auxiliary steering actuator 6 may be applied to any of the first and second embodiments. The driving force of the motor 27 is transmitted to a drive pulley 51 coupled to the motor shaft 27a, and is transmitted by a belt 53 to a driven pulley 52 disposed in parallel with the motor shaft 27a. The pulleys 51 and 52 and the belt 53 constitute a wrapping-type speed reducer 28.

  A screw shaft 54 in a linear motion mechanism 29 including a feed screw mechanism is disposed in a screwed state on a nut 55 on the inner periphery of the driven pulley 52. The nut 55 and the screw shaft 54 have a screw groove and a screw thread that constitute a screw portion 58 of a slide screw, specifically, a trapezoidal screw having a self-locking function. By rotating the nut 55 that rotates integrally with the driven pulley 52, the screw shaft 54 is prevented from rotating by the rotation preventing portion 56, so that the screw shaft 54 linearly moves back and forth.

An arm-shaped auxiliary turning force transmitted portion 18 provided on the outer ring 11 of the hub bearing 3 is connected to the linear motion output portion 29 a at the tip of the screw shaft 54 via a joint 57. The joint 57 is rotatably connected to the auxiliary turning force transmitted portion 18 and the linear motion output portion 29a by two pins 57a. For this reason, the entire hub unit body 4 including the hub bearing 3 can rotate around the auxiliary turning shaft center A with respect to the unit support member 5 (5A) by moving the screw shaft 54 back and forth.
In this embodiment, the driven pulley 52 and the nut 55 of the linear motion mechanism 29 are combined with each other, but the driven pulley 52 and the nut 55 are manufactured integrally with each other. It may be a part of the parts.

  In this way, when a slide screw having a self-lock function is used for the linear motion mechanism 29, reverse input from the tire is prevented, and even if the motor 27 fails, the tire 9 may be staggered due to the self-lock function. In addition, the vehicle can be brought to a safe place by operating the steering wheel, and safety is ensured. In addition, when the linear motion mechanism 29 has a self-locking function, a motor for maintaining a constant auxiliary steering angle can be maintained even when auxiliary steering is not performed or when traveling at a high speed. 27 drive is unnecessary, and motor power can be reduced.

  FIG. 14 shows another specific example of the auxiliary steering actuator 6. The auxiliary steering actuator 6 in the figure may also be applied to any of the first and second embodiments. The driving force of the motor 27 is transmitted to a drive gear 59 coupled to the motor shaft 27a, and is transmitted to a driven gear 60 disposed in parallel with the motor shaft 27a. The drive gear 59 and the driven gear 60 constitute a gear train that serves as the speed reducer 28.

  A screw shaft 54 in a linear motion mechanism 29 including a feed screw mechanism is disposed in a screwed state with a nut 55A provided at the center of the driven gear 60. The configuration of the linear motion mechanism 29 and the connection between the linear motion mechanism 29 and the hub unit body 4 are the same as in the example shown in FIG. That is, the nut 55A and the threaded portion 58 of the screw shaft 54 are sliding screws, specifically, trapezoidal screws having a self-locking function. By rotating the nut 55 that rotates integrally with the driven pulley 52, the screw shaft 54 is prevented from rotating by the rotation preventing portion 56, so that the screw shaft 54 linearly moves back and forth.

An arm-shaped auxiliary turning force transmitted portion 18 provided on the outer ring 11 of the hub bearing 3 is connected to the linear motion output portion 29 a at the tip of the screw shaft 54 via a joint 57. The joint 57 is rotatably connected to the auxiliary turning force transmitted portion 18 and the linear motion output portion 29a by two pins 57a. For this reason, the entire hub unit body 4 including the hub bearing 3 can rotate around the auxiliary turning axis A with respect to the unit support member 5 by moving the screw shaft 54 back and forth.
In this embodiment, the driven gear 60 and the nut 55 of the linear motion mechanism 29 are manufactured integrally. However, the driven gear 60 and the nut 55 are manufactured integrally with each other and coupled to each other. It may be a thing.

  Also in this embodiment, since the slide screw having a self-locking function is used for the linear motion mechanism 29 as in the embodiment of FIG. 13, the above-described effects due to the self-locking function can be obtained. In the case of this embodiment, since the reduction gear 28 is composed of a gear train, it is possible to transmit the drive with high rigidity and high responsiveness.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 ... Hub unit 2 with an auxiliary steering function ... Wheel 3 ... Hub bearing 4 ... Hub unit main body 5 ... Unit support member 5A ... Unit support member 6 ... Actuator for auxiliary steering 6a ... Linear motion output part 7 ... Rotation permission support component 7A: Rotation-supporting support component 9 ... Tire 9a ... Tire contact surface 10 ... Vehicle 10A ... Vehicle body 11 ... Outer ring 12 ... Inner ring 13 ... Rolling element 12c ... Hub flange 14 ... Brake 14a ... Brake rotor 14b ... Brake caliper 15 ... Rotation side component 16 ... Fixed side part 18 ... Auxiliary turning force receiving part 21 ... Suspension device 22 ... Knuckle 25 ... Steering device 26 ... Tie rod 27 ... Motor 28 ... Reduction gear 29 ... Linear motion mechanism 35 ... Stopper 36 ... Brake caliper mounting part 48, 48A ... Preloading means 51 ... Drive pulley 52 ... Driven pulley 53 ... Bolt 54 ... Screw shaft 55 ... Nut 5 ... detent portions 57 ... joint 57a, 57 b ... pin 58 ... Screw portion 59 ... drive gear 60 ... driven gear A ... auxiliary steering axis K ... kingpin axis O ... rotation axis _{P K} ... intersection _{P A} ... intersection S ... Road surface θ ... Auxiliary steering angle

Claims (6)

  A hub unit body having hub bearings for supporting wheels, and a hub unit that is installed on a vehicle body via a suspension device, and rotates at two locations above and below the hub unit body so as to be rotatable around an auxiliary turning shaft center extending in the vertical direction. A unit support member supported via an allowable support component; and an auxiliary steering actuator that is installed on the unit support member and rotates the hub unit body about the auxiliary steering axis. An auxiliary steering function in which the actuator is composed of a motor and a linear motion mechanism that converts the rotational output of the motor into a linear motion, and the linear motion output portion of the linear motion mechanism is rotatably connected to the hub unit body Hub unit with.   The hub unit with an auxiliary turning function according to claim 1, wherein the auxiliary turning actuator further includes a speed reducer that decelerates the rotation of the motor.   The hub unit with an auxiliary turning function according to claim 2, wherein the speed reducer includes a winding transmission mechanism, and the linear movement mechanism is a feed screw mechanism of a sliding screw.   The hub unit with an auxiliary turning function according to claim 2, wherein the speed reducer includes a gear train, and the linear motion mechanism is a feed screw mechanism of a sliding screw.   The auxiliary turning function hub unit with an auxiliary turning function according to any one of claims 1 to 4, wherein a sliding screw feed screw mechanism constituting the linear motion mechanism has a self-locking function. Hub unit with.   A vehicle in which one or both of the front wheels and the rear wheels are supported by using the auxiliary steering function-equipped hub unit according to any one of claims 1 to 5.

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