JP2005255023A - Suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make uniform the load applied to a front and a rear bolt for fastening a lower arm supporting bracket to the lower part of a knuckle body. <P>SOLUTION: A knuckle 13 is formed so that the front and rear of the lower arm supporting bracket 15 are fastened by the front 17 and rear bolts 19 to a front 14c and a rear fastening part 14d provided in the lower part of the knuckle body 14, and when the knuckle 13 makes a bump from the normal position, the angle of a straight line L tying together the fastening surfaces of the fastening parts 14c and 14d approaches horizontal. This causes the vehicle body to incline by the centrifugal force in association with the vehicle turning its head in the direction outward in the turning direction to result in a bump of the outer wheels in turning, and also a lateral force in turning directed inward in the turning direction is applied to the grounding point of each outer wheel, and thereby the difference between the distances from the road surface to the fastening surfaces of the fastening parts 14c and 14d lessens when the compressive load on a lower arm 12 resisting against the lateral force in turning is fed to the lower arm supporting bracket 15, and the difference between the loads applied to the front 17 and rear bolts 19 arranged there is decreased to allow making the durability uniform. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes a knuckle formed by fastening front and rear portions of a lower arm support bracket with front and rear bolts to a front fastening portion and a rear fastening portion provided at a lower portion of a knuckle body, and an inner end in a vehicle width direction is connected to a vehicle body. And a lower arm whose outer end in the vehicle width direction is connected to the lower arm support bracket, and the angle of the straight line connecting the fastening surfaces of the front fastening portion and the rear fastening portion changes with the knuckle bump and rebound. Relates to the device.

  FIG. 7 shows a knuckle 01 of a conventional suspension device. The knuckle 01 has a lower arm support bracket 03 connected to the lower end of the knuckle body 02 by two bolts 04 and 05, and an upper portion at the upper end of the knuckle body 01. The outer end in the vehicle width direction of the arm 06 is connected, and the outer end in the vehicle width direction of the lower arm 07 is connected to the lower arm support bracket 03. A pair of fastening portions 02a and 02b projecting downward is integrally formed at the front and rear ends of the lower portion of the knuckle body 02, and the front and rear ends of the lower arm support bracket 03 are bolts 04 on the fastening surfaces of these fastening portions 02a and 02b. , 05.

  When the vehicle turns at a high speed, the vehicle body tilts outward in the turning direction due to the centrifugal force accompanying the turning, the turning outer wheel bumps, and a turning lateral force inward in the turning direction acts on the grounding point of the turning outer wheel. As shown in FIG. 7, in the knuckle 01 of the conventional suspension device, the straight line L connecting the fastening surfaces of the fastening portions 02a and 02b before and after fastening the lower arm support bracket 03 to the knuckle body 02 is in a normal state (1G in the vertical direction). When the wheel is bumped, when the wheel bumps, the straight line L further moves forward to the position of L ′ with the forward and downward inclination further strengthened. As a result, the difference in height between the front and rear bolts 04 and 05 from the road surface becomes large, and when the above-mentioned turning lateral force is applied, the load acting on the rear bolt 05 for the reason described in the embodiment. Is larger than the load acting on the front bolt 04, and if the front and rear bolts 04, 05 having the same diameter are used, there is a problem that the durability of the rear bolt 05 that receives a large load decreases. .

  The present invention has been made in view of the above-described circumstances, and an object thereof is to uniformize the load applied to the bolts before and after fastening the lower arm support bracket to the lower part of the knuckle body.

  In order to achieve the above object, according to the first aspect of the present invention, the front and rear portions of the lower arm support bracket are fastened with the front and rear bolts to the front fastening portion and the rear fastening portion provided at the lower portion of the knuckle body. A knuckle configured as described above, and a lower arm whose inner end in the vehicle width direction is connected to the vehicle body and whose outer end in the vehicle width direction is connected to the lower arm support bracket, and the fastening surfaces of the front fastening portion and the rear fastening portion are provided. In the suspension apparatus in which the angle of the connecting straight line changes with the knuckle bump and rebound, the suspension apparatus is proposed in which the angle of the straight line approaches to the horizontal as the knuckle bumps from the normal position.

  According to the configuration of claim 1, when the knuckle formed by fastening the front and rear portions of the lower arm support bracket with the front and rear bolts to the front fastening portion and the rear fastening portion provided at the lower portion of the knuckle main body bumps from the normal position. The angle of the straight line connecting the fastening surfaces of the front side fastening part and the rear side fastening part approaches horizontal. Therefore, the vehicle body tilts outward in the turning direction due to the centrifugal force associated with the turning of the vehicle, the turning outer wheel bumps, and the turning lateral force acting inward in the turning direction acts on the grounding point of the turning outer wheel. When the compressive load of the opposing lower arm is input to the lower arm support bracket, the difference in the distance from the road surface to the fastening surface of the front fastening part and the rear fastening part becomes small, and the load applied to the front and rear bolts arranged there It is possible to make the durability uniform by reducing the difference between the two.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 5 show a first embodiment of the present invention. FIG. 1 is a perspective view of a double wishbone suspension of a left rear wheel, FIG. 2 is a view in the direction of the arrow 2 in FIG. FIG. 4 is an enlarged cross-sectional view of the main part of FIG. 3, and FIG. 5 is an operation explanatory diagram when a turning lateral force is input to the bumped wheel.

  As shown in FIGS. 1 to 3, the double wishbone suspension device S includes a knuckle 13 supported by a vehicle body by an upper arm 11 and a lower arm 12. The knuckle 13 includes a knuckle body 14 made of light alloy forging, and a lower arm support bracket 15 made of an iron-based material fastened to the lower part thereof. The knuckle body 14 includes an axle support portion 14a that rotatably supports the axle of the wheel W, and an upper arm support portion 14b that extends upward from the axle support portion 14a, and a ball joint at the upper end of the upper arm support portion 14b. 16, the outer end of the upper arm 11 in the vehicle width direction is pivotally supported.

  As is apparent from FIG. 4, a pair of front and rear fastening portions 14c and 14d protrude downward from the lower front and rear ends of the axle support portion 14a of the knuckle body 14, and a recess recessed upwardly between the two fastening portions 14c and 14d. 14e is formed. The lower arm support bracket 15 includes front and rear end mounting portions 15a and 15b, a central lower arm support portion 15c, and a pair of inclined connection portions 15d and 15e that connect the mounting portions 15a and 15b and the lower arm support portion 15c. The front mounting portion 15a is fixed to the fastening surface of the front fastening portion 14c with bolts 17 and nuts 18, and the rear mounting portion 15b is fixed to the fastening surface of the rear fastening portion 14d with bolts 19. The lower arm support portion 15c of the lower arm support bracket 15 is positioned lower than the mounting portions 15a and 15b, and the lower arm 12 is formed in a space 20 formed between the recess 14e of the knuckle body 14 and the lower arm support portion 15c of the lower arm support bracket 15. The vehicle width direction outer end of is arranged.

  The ball joint 21 that pivotally supports the outer end in the vehicle width direction of the lower arm 12 to the lower arm support bracket 15 includes a spherical head 22a, a conical shaft portion 22b that is continuous with the head portion 22a, and a male screw portion 22c that is continuous with the shaft portion 22b. The ball stud 22 comprised by these is provided. The shaft portion 22b of the ball stud 22 passes through the mounting hole 15f provided in the lower arm support portion 15c of the lower arm support bracket 15 from the top to the bottom, and the nut 23 is screwed into the male screw portion 22c protruding downward from the lower arm support portion 15c. It is fixed by that. The ball joint 21 includes a cup-shaped housing 12 a provided at the end of the lower arm 12. A synthetic resin bearing 25 slidably contacting the head 22a of the ball stud 22 is housed on the inner peripheral surface of the housing 12a, and is held by a retainer 26 fixed so as to cover the opening of the housing 12a. A boot 27 is mounted between the opening of the housing 12a and the lower arm support portion 15c of the lower arm support bracket 15 so that dust and the like do not enter the head 22a of the ball stud 22 and the sliding surface of the bearing 25.

  As shown in FIG. 4, the straight line L connecting the fastening surfaces of the fastening portions 14 c and 14 d on the front and rear of the knuckle body 14 is inclined downward in the normal direction, that is, when 1 G acceleration is applied in the vertical direction. When the wheel W bumps upward, the suspension geometry is set so that the straight line L rises and becomes horizontal (see the straight line L ′).

  Now, when the vehicle turns, a load is applied to the vehicle body that is inclined outward in the turning direction by centrifugal force and presses the outer turning wheel against the road surface. Therefore, the turning outer wheel bumps relative to the vehicle body. As shown in FIG. 5, in the turning outer wheel, a turning lateral force inward in the vehicle width direction from the road surface acts on the ground contact point of the wheel W, and a moment M acts on the knuckle 13 by the turning lateral force. 12 is canceled out by the reaction force FL of the compressive stress acting on 12 and the reaction force FU of the tensile stress acting on the upper arm 11. At this time, the load acting on the bolts 17 and 19 before and after connecting the knuckle body 14 and the lower arm support bracket 15 is caused by the moment M to swing the knuckle 13 from the fastening surfaces of the fastening portions 14 c and 14 d on the front and rear of the knuckle body 14. The smaller the distance A to the center (substantially the center of the wheel W), that is, the greater the distance to the fastening surface of the fastening portions 14c and 14d measured from the road surface, the greater the distance A.

  Therefore, if the heights of the fastening surfaces of the front and rear fastening portions 14c and 14d are unbalanced as in the conventional example described with reference to FIG. 7, the load acting on the front and rear bolts 17 and 19 becomes unbalanced, resulting in durability. Becomes uneven, and it is necessary to take measures such as changing the thicknesses of the bolts 17 and 19.

  However, in the present embodiment, when the wheel W on the outer side in the turning direction bumps relative to the vehicle body when the vehicle turns, the straight line L connecting the fastening surfaces of the front and rear fastening portions 14c and 14d of the knuckle body 14 is in a forwardly lowered state. Therefore, the difference in height from the road surface of the fastening surfaces of the front and rear fastening portions 14c and 14d is reduced. Therefore, when the moment M acts on the knuckle 13 by the inward turning lateral force acting from the road surface to the ground contact point of the wheel W outside the turning direction, the knuckle body 14 and the lower arm support bracket 15 are joined before and after joining. Since the load acting on the bolts 17 and 19 is made uniform, it is not necessary to take measures such as thickening the bolt to which a large load is applied because it is close to the rocking center of the knuckle 13, and on one of the front and rear bolts 17 and 19. Durability can be enhanced by preventing a large load from acting.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the first embodiment, the ball stud 22 of the ball joint 21 is fixed to the lower arm support bracket 15, but in the second embodiment, the housing 24 of the ball joint 21 is fixed to the lower arm support bracket 15. That is, the housing 24 of the ball joint 21 is press-fitted from the top to the bottom into the mounting hole 15 f formed in the lower arm support portion 15 c of the lower arm support bracket 15. The outer end in the vehicle width direction of the lower arm 12 is fitted to a ball stud 22 protruding downward from the housing 24 and fastened by a nut 28.

  Also in the second embodiment, the straight line L connecting the fastening surfaces of the fastening portions 14c and 14d on the front and rear of the knuckle body 14 is inclined downwardly at the normal time when 1G acceleration is applied to the vehicle, but the wheel W is upward. The suspension geometry is set so that the straight line L rises and becomes horizontal when bumped (see the straight line L ′).

  Therefore, the second embodiment can achieve the same operation and effect as the first embodiment described above.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, in the embodiment, the double wishbone type suspension apparatus S is illustrated, but the present invention can be applied to any other type of suspension apparatus.

  In the embodiment, the front bolt 17 is a stud bolt and the rear bolt 19 is a normal bolt, but the type of the bolt can be arbitrarily selected.

  In the embodiment, the front and rear bolts 17 and 19 have the same thickness, but it is not always necessary.

Perspective view of left wish wheel double wishbone suspension 2 direction view of FIG. 3 direction enlarged arrow view of FIG. 3 is an enlarged cross-sectional view of the main part of FIG. Action diagram when turning lateral force is input to bumped wheel The figure corresponding to the said FIG. 4 based on 2nd Example. FIG. 2 is a diagram corresponding to FIG.

Explanation of symbols

12 Lower arm 13 Knuckle 14 Knuckle body 14c Fastening portion 14d Fastening portion 15 Lower arm support bracket 17 Bolt 19 Bolt L A straight line connecting the fastening surfaces of the front fastening portion and the rear fastening portion

Claims (1)

The front and rear fastening parts (14c) and the rear fastening part (14d) provided at the lower part of the knuckle body (14) are fastened to the front and rear parts of the lower arm support bracket (15) with the front and rear bolts (17, 19). A knuckle (13) and a lower arm (12) having an inner end in the vehicle width direction connected to the vehicle body and an outer end in the vehicle width direction connected to the lower arm support bracket (15), and a front fastening portion (14c) and In the suspension device in which the angle of the straight line (L) connecting the fastening surface of the rear fastening portion (14d) changes with the bump and rebound of the knuckle (13),
As the knuckle (13) bumps from the normal position, the angle of the straight line (L) approaches horizontal.

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