JP2009241712A - Steering device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device for vehicle compatible with countermeasures against shimmy and a shock absorption function in a steering system and a linearity problem to a vehicle steering in a higher dimension. <P>SOLUTION: An expansion part 20 having no restraint of an steering angle between right and left wheels and allowing an expansion in the right and left directions is provided only with one of a linking section from an input point of a steering effort of a linking mechanism section in a steering mechanism to a connecting point of either a left wheel or a right wheel, or another linking section from the input point of the steering effort to the connecting point of the other wheel. For example, the expansion part 20 is composed by inserting a male-like axis part 22 on a rack axis 12l side in the left into a female-like axis part 21 on the knuckle arm 9fl side in the left which is provided in a knuckle arm 9fl and the end thereof is formed into a shape of cylinder, and providing a clearance part 23 between an axis end of the male-like axis part 22 and the female-like axis part 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle steering apparatus that steers left and right wheels by inputting a steering force to a link mechanism.

  2. Description of the Related Art Conventionally, in a vehicle steering device, an impact absorbing portion is provided at a link portion from a connecting point of one of left and right wheels to a connecting point of the other wheel for the purpose of providing a countermeasure against shimmy and an impact absorbing function. It has been proposed and put into practical use.

For example, Japanese Patent Application Laid-Open No. 2005-75116 discloses a technique in which a vibration isolator for preventing transmission of vibration is provided on left and right tie rods in a steering device.
JP-A-2005-75116

  By the way, the linearity of the vehicle response such as the yaw rate with respect to the small steering angle steering is very important in the vehicle control by the driver. This is considered because the driver determines the steering amount in a feed-forward manner based on the vehicle response at the initial stage of steering. For example, a driver is required for driving a vehicle in which a yaw rate proportional to the steering amount is generated after the steering angle has increased to some extent since a yaw rate proportional to the steering amount (steering torque or steering angle) does not occur in the initial stage of steering. The above steering and correction steering are frequently repeated. From this point of view, the technique of providing a vibration isolator as disclosed in the above-mentioned Patent Document 1 is a factor that hinders linearity with respect to steering, and it is desired to solve these problems. It has been.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a vehicle steering apparatus capable of achieving both a countermeasure against shimming and an impact absorbing function in a steering system and a linearity problem with respect to steering of a vehicle at a high level. To do.

  According to the present invention, in a vehicle steering apparatus that steers left and right wheels by inputting a steering force to a link mechanism unit, one of a link point from a steering force input point of the link mechanism unit to a connection point of one of left and right wheels. Only one of the link part and the other link part from the input point of the steering force to the connection point of the other wheel is provided with an extension part that eliminates the restriction of the steering angle between the left and right wheels and allows the extension in the left-right direction. It is characterized by providing.

  According to the vehicle steering device of the present invention, it is possible to achieve both a countermeasure against shimming and an impact absorbing function in a steering system and a linearity problem with respect to vehicle steering at a high level.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a first embodiment of the present invention, FIG. 1 is an explanatory view showing a schematic configuration of a vehicle front wheel steering device, and FIG.

  In FIG. 1, reference numeral 1 denotes a front wheel steering device for a vehicle. The front wheel steering device 1 has a steering shaft 3 extending from a steering wheel (handle) 2, and a front end of the steering shaft 3 is connected to a universal joint 4a. And a pinion shaft 6 protruding from the steering gear box 5 through a joint portion 4 including a joint shaft 4b and a joint shaft 4b.

  From the steering gear box 5, a tie rod 8fl extends toward the left front wheel 7fl, while a tie rod 8fr extends toward the right front wheel 7fr.

  The tie rod ends of the tie rods 8fl and 8fr are connected to axle housings 10fl and 10fr that rotatably support the wheels 7fl and 7fr on the respective sides via knuckle arms 9fl and 9fr.

  The steering gear box 5 is provided with a pinion gear 11 at the tip of the pinion shaft 6, and the pinion gear 11 is engaged with the rack 12. The rack shaft 121 extending to the left side of the rack 12 is connected to the left tie rod 8fl, and the rack shaft 12r extending to the right side of the rack 12 is connected to the right tie rod 8fr. In the figure, point PG indicates the meshing point of the rack and pinion, that is, the input point of the steering force. In the first embodiment of the present invention, one link portion is from point PG to the left front wheel 7fl. The left tie rod 8fl, the knuckle arm 9fl, and the rack shaft 12l are configured, and the other link portion includes the right tie rod 8fr, the knuckle arm 9fr, and the rack shaft 12r from the point PG to the right front wheel 7fr. It is configured.

  In the middle of the left tie rod 8fl, there is provided an expansion / contraction part 20 that eliminates the restriction of the steering angle between the left and right wheels and allows the expansion / contraction in the left / right direction.

  As shown in FIG. 2, the expansion / contraction part 20 has a male shaft part 22 on the left rack shaft 12l side inserted into a female shaft part 21 on the left knuckle arm 9fl side having an end formed in a cylindrical shape. The gap between the male shaft 22 and the female shaft 21 is provided at the shaft end of the male shaft 22.

  A disc-shaped disk portion 22 a having an outer diameter smaller than the inner surface of the female shaft portion 21 and larger than the male shaft portion 22 is formed at the end of the male shaft portion 22. In FIG. 2, reference numeral 22o indicates an end surface of the disk portion 22a facing the inner end surface 21o of the cylindrical portion of the female shaft portion 21, and reference numeral 22i indicates an end surface of the disk portion 22a on the male shaft portion 22 side. Indicates.

  Further, between the inner surface of the female shaft portion 21 and the outer surface of the male shaft portion 22, the bending displacement of the shaft (tie rod 8fl) connected by the female shaft portion 21 and the male shaft portion 22 is suppressed. Further, a cylindrical guide member 24 made of metal that enables smooth expansion and contraction of the tie rod 8fl is interposed.

  The gap portion 23 is restricted from moving in the contraction direction of the tie rod 8fl when the end surface 22o of the disc portion 22a abuts against the inner end surface 21o of the female shaft portion 21, and the movement of the tie rod 8fl in the extension direction is controlled by the disc. The end surface 22 i of the portion 22 a is regulated by contacting the end surface 24 o of the guide member 24. The allowable extension / contraction length is set to, for example, 1 to 2 mm, and the clearance 23 eliminates the restriction of the steering angle between the left and right wheels, and allows the extension / contraction in the left / right direction. Yes.

  On the other hand, the right tie rod 8fr does not have the above-described telescopic portion 20 provided on the left tie rod 8fl, but connects the right knuckle arm 9fr and the right rack shaft 12r with a single bar-like member.

  And by setting it as such a structure, from the connection point of the right or left wheel of the link mechanism part of the steering apparatus 1 to the connection point of the other wheel so that the moment around a kingpin may become 0 autonomously. Since the length of is adjusted, the tensile force applied to this portion and the compressive force can be reduced. When the vehicle is steered, the wheel can be quickly steered without pulling or interfering with the compression force, so that a lateral force that is linear with respect to steering can be generated. Therefore, it is possible to realize a behavior with high linearity with respect to steering, which is difficult with a conventional vehicle. As described above, according to the first embodiment, it is possible to achieve both a countermeasure against shimming and an impact absorbing function in the steering system and a linearity problem with respect to steering of the vehicle at a high level. Here, in the first embodiment, the above-described telescopic portion 20 is not provided on either the left tie rod 8fl or the right tie rod 8fr, and steering is performed even when compared with a configuration in which the steering angle between the left and right wheels is restricted. Excellent in terms of linearity. This is because there is a difference in force between the left and right wheels due to various factors. Therefore, in the configuration in which the steering angle between the left and right wheels is constrained as in the comparison target, the steering force for turning one of the wheels is reduced. On the other hand, the force generated on the other wheel becomes a braking force that hinders steering, and the steering of one wheel is delayed.

Next, FIG. 3 is a cross-sectional view of the main part of the stretchable part according to the second embodiment of the present invention.
In the second embodiment, the metal contacts are prevented from being generated by the expansion and contraction of the tie rod 8fl, that is, the relative movement of the female shaft portion 21 and the male shaft portion 22. Unlike the first embodiment, other configurations and operational effects are the same as those of the first embodiment, so the same components are denoted by the same reference numerals and description thereof is omitted.

  That is, as shown in FIG. 3, in the telescopic portion 30 according to the second embodiment, the metal contact with the inner end surface 21o is provided on the end surface 22o facing the inner end surface 21o of the female shaft portion 21 of the disk portion 22a. In order to prevent this, a disk-like member 31 made of resin or rubber is attached.

  A ring-shaped member 32 made of resin or rubber is attached to the end surface 22i of the disk portion 22a on the male shaft portion 22 side in order to prevent metal contact with the end surface 24o of the guide member 24.

  By adopting such a configuration, in addition to the effects described in the first embodiment, metal contact is prevented, and it is possible to achieve a long life and quietness of the stretchable portion 20.

  Note that the disk-shaped member 31 and the ring-shaped member 32 that prevent metal contact may be attached to the respective end surfaces, that is, the inner end surface 21o of the female shaft portion 21 and the end surface 24o of the guide member 24.

  Needless to say, the member for preventing the metal contact can be applied to each of the embodiments described later as needed.

Next, FIG. 4 is a fragmentary cross-sectional view of an extendable part according to a third embodiment of the present invention.
In the third embodiment, a configuration that allows the vibration from the wheel to the steering to be cut off is added to the first embodiment, and other configurations and operational effects are the same as those in the first embodiment. Since they are similar, the same components are denoted by the same reference numerals, and description thereof is omitted.

  That is, as shown in FIG. 4, in the telescopic portion 40 according to the third embodiment, a cylindrical elastic member 41 is interposed between the inner surface of the guide member 24 and the outer surface of the male shaft portion 22. Yes. For this reason, in addition to the effect of the first embodiment, there is an effect that the elastic member 41 reliably blocks the vibration from the wheel to the steering.

Next, FIG. 5 is a cross-sectional view of the main part of the telescopic part according to the fourth embodiment of the present invention.
The fourth embodiment is different from the third embodiment in that, in the third embodiment, the bending displacement of the shaft (tie rod) connected by the female shaft portion and the male shaft portion is suppressed. The other configurations and functions and effects are the same as those of the third embodiment, and therefore the same components are denoted by the same reference numerals and description thereof is omitted.

  That is, as shown in FIG. 5, in the telescopic portion 50 according to the fourth embodiment, a disc-like disc portion 51 that is in sliding contact with the inner surface of the female shaft portion 21 is formed at the end of the male shaft portion 22. ing. In addition to the effect of the third embodiment, the disk portion 51 can more reliably suppress the bending displacement of the shaft (tie rod 8fl) connected by the female shaft portion 21 and the male shaft portion 22. It is like that.

Next, FIG. 6 is a cross-sectional view of the main part of the telescopic part according to the fifth embodiment of the present invention.
The fifth embodiment is different from the first embodiment in that the fifth embodiment is configured so that the tie rod 8fl can be expanded and contracted more smoothly in the first embodiment. Since it is the same as that of 1 form, the same code | symbol is described to the same structure and description is abbreviate | omitted.

  That is, as shown in FIG. 6, in the telescopic part 60 according to the fifth embodiment, the gap 23 is made of rubber between the end face 22o of the disk part 22a and the inner end face 21o of the female shaft part 21. A ring-shaped elastic member 61 is interposed. A rubber ring-shaped elastic member 62 is also interposed between the end surface 22 i of the disk portion 22 a and the end surface 24 o of the guide member 24 in the gap portion 23. The two elastic members 61 and 62 allow the relative movement between the female shaft 21 and the male shaft 22 to be performed more smoothly.

  Next, FIGS. 7 and 8 show a sixth embodiment of the present invention, FIG. 7 is an enlarged view of the main part of the extendable part, and FIG. 8 is an enlarged view of the main part of the extendable part of an example different from FIG. . The sixth embodiment is different from the first to fifth embodiments in that the stretchable portion is provided with an integral spring having elasticity in the stretchable direction. This is the same as the first embodiment, and the description is omitted.

  That is, as shown in FIG. 7, the expansion / contraction part 70 according to the sixth embodiment is formed by providing an integral coil spring 71 having elasticity in the expansion / contraction direction in the middle part of the tie rod 8fl. By adopting such a configuration, the same effect as in the first embodiment can be obtained.

  In addition, as a configuration in which such a spring is provided, a simpler U-shaped spring 72 as shown in FIG. 8 may be provided.

  In each of the embodiments described above, the example in which the expansion / contraction part is provided on the tie rod 8fl has been described. You may make it provide.

Explanatory drawing which shows schematic structure of the front-wheel steering apparatus of the vehicle by 1st Embodiment of this invention. Same as above, sectional view of the main part Sectional drawing of the principal part of the expansion-contraction part by 2nd Embodiment of this invention Sectional drawing of the principal part of an expansion-contraction part by 3rd Embodiment of this invention Sectional drawing of the principal part of an expansion-contraction part by 4th Embodiment of this invention Sectional drawing of the principal part of the expansion-contraction part by 5th Embodiment of this invention The principal part enlarged view of the expansion-contraction part by the 6th Embodiment of this invention Same as above, enlarged view of the main part of the expansion / contraction part of an example different from FIG.

Explanation of symbols

1 Front wheel steering device 2 Steering wheel (handle)
DESCRIPTION OF SYMBOLS 3 Steering shaft 4 Joint part 5 Steering gear box 6 Pinion shaft 7fl, 7fr Front wheel 8fl, 8fr Tie rod 9fl, 9fr Knuckle arm 11 Pinion gear 12 Rack 12l, 12r Rack shaft 20 Telescopic part 21 Female shaft part 22 Male shaft part 22a Disk Part 23 gap part 24 guide member

Claims (10)

In a steering apparatus for a vehicle that steers left and right wheels by inputting a steering force into a link mechanism,
Either one link part from the steering force input point of the link mechanism part to the left or right wheel connection point, or the other link part from the steering force input point to the other wheel connection point A vehicle steering apparatus characterized in that only one of them is provided with an expansion / contraction portion that eliminates the restriction of the steering angle between the left and right wheels and allows expansion / contraction in the left / right direction.   The expansion / contraction portion is formed by inserting a male shaft portion into a female shaft portion having an end portion formed in a cylindrical shape so that the male shaft portion and the female shaft portion are relatively movable. The vehicle steering apparatus according to claim 1.   3. The vehicle steering apparatus according to claim 2, wherein the expansion / contraction part is formed by providing a gap with the female shaft part at a shaft end of the male shaft part.   The vehicle steering apparatus according to claim 3, wherein an elastic member is interposed in the gap portion.   Between the inner surface of the female shaft portion and the outer surface of the male shaft portion, a guide member that suppresses bending displacement of the shaft connected by the female shaft portion and the male shaft portion is interposed. The vehicle steering device according to any one of claims 2 to 4, wherein   6. The vehicle steering apparatus according to claim 5, wherein an elastic member is interposed between an inner surface of the guide member and an outer surface of the male shaft portion.   The vehicle steering apparatus according to any one of claims 2 to 6, wherein an end portion of the male shaft portion is formed in a disk shape that is in sliding contact with an inner surface of the female shaft portion.   2. The vehicle according to claim 1, wherein the expansion / contraction part is formed by providing an integral spring having elasticity in at least the expansion / contraction direction only in one of the one link part and the other link part. Steering device.   The vehicle according to any one of claims 1 to 8, wherein the one link portion and the other link portion each include a rack shaft, a tie rod, and a knuckle arm. Steering device.   10. The vehicle steering apparatus according to claim 9, wherein the expansion / contraction part is provided on the tie rod of only one of the one link part and the other link part.

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