JP2009107511A - Suspension structure - Google Patents

Abstract

Variations due to accumulation of dimensional tolerances of parts can be absorbed.
A first member that pivotally supports an axle, a second member that pivotally supports an upper side of the first member via first pivotal support means, and a first member that pivotally supports the first member via second pivotal support means. A third member that pivotally supports the lower side, and a fourth member that is fastened to the first and second members, wherein the swing shaft of the first and second pivotal support means is formed in a tapered shape; Bolt holes 24 and 26 for fastening the second member and bolt holes 28 and 30 for fastening the third member are formed in the member, and the bolt hole on the side close to the kingpin axis L _KP among the bolt holes 24 and 26. The bolt hole 26 on the side far from the kingpin axis L _KP is formed so that the tolerance of the hole diameter of 24 is minimized, and the vertical hole diameter of the minimum tolerance allowed in the axial direction of the kingpin axis L _KP and the kingpin axis L for radial _KP is formed in a long hole having a larger lateral hole diameter than the vertical hole diameter, the tolerance of the bolt holes 28, 30 Bo Is set larger than the tolerance of the bets hole 24.
[Selection] Figure 5

Description

  The present invention particularly relates to an automobile front suspension structure.

In general, a suspension of an automobile is configured by interconnecting a plurality of members such as various arms and a steering knuckle so as to be relatively movable by bolts and ball joints.
For example, Patent Document 1 discloses a configuration in which a knuckle 102 that supports an axle 101 and a suspension arm 103 are connected via ball joints 104 and 105 at two upper and lower points as shown in FIG. In this case, the line connecting the centers of the bearings 104a and 105a of the upper and lower ball joints 104 and 105 is the kingpin axis L _KP (rotation axis of the steering wheel).

By the way, each of these suspension members includes a design or manufacturing tolerance. Therefore, when such a tolerance is accumulated, a variation in dimensions occurs. If such a variation occurs, a load more than necessary is applied to the ball joints 104 and 105 when the suspension member is assembled, and an undesirable influence (for example, a decrease in durability performance) is given.
On the other hand, in the configuration shown in FIG. 6, the studs 104b and 105b of the upper and lower ball joints 104 and 105 are formed in a tapered shape at two locations, thereby improving the accuracy of the axial alignment of the ball joints 104 and 105, The positioning accuracy of the kingpin shaft L _KP is increased.

However, in this case, the tolerance variation in the kingpin axis direction may be increased. Therefore, in this technique, as shown in FIG. 6, a structure is proposed in which a spring 106 is provided on the bearing 104 a of the upper ball joint 104 to absorb axial variation by the biasing force of the spring 106.
JP 2000-161340 A

However, in such a conventional technique, there is a risk that the rotational torque of the ball joints 104 and 105 varies due to variations in the spring reaction force, or that the cost increases due to an increase in the number of parts.
The present invention was devised in view of such a problem, and an object of the present invention is to provide a suspension structure that can absorb variations due to accumulation of dimensional tolerances of each component without causing an increase in cost.

  For this reason, the present invention according to claim 1 is directed to a first member that rotatably supports the axle of the vehicle, a fixed member fixed to the strut of the vehicle, and an upper end of the first member via the first shaft support means. A second member that pivotably supports the side, a third member that pivotally supports the lower end side of the first member via the second pivot support means, the first member, and the first member It has a sheet metal-like fourth member that fastens the two members with bolts, and is formed in a taper shape so that the swing shafts of the first and second shaft support means both have a smaller diameter toward the tip. In the suspension structure thus formed, first and second bolt holes for fastening the second member and third and fourth bolt holes for fastening the third member are formed in the fourth member. Of the first and second bolt holes, close to the kingpin shaft connecting the centers of the swing shafts of the first and second shaft support means The second bolt hole formed on the side farther from the kingpin shaft is formed such that the tolerance of the hole diameter of the first bolt hole formed on the outer surface is the minimum tolerance allowed for machining. The vertical hole diameter of the minimum tolerance allowed for machining in the kingpin shaft direction is formed in a long hole shape having a horizontal hole diameter larger than the vertical hole diameter in the radial direction of the kingpin shaft. The third and fourth bolt holes are both formed with a tolerance larger than the tolerance of the hole diameter of the first bolt hole.

  In addition to the structure of claim 1, the suspension structure according to claim 2 is connected to the third member so as to be swingable with respect to the third member, and the base end side is swingable with respect to the vehicle. It is characterized by a further lower arm that can be connected.

  According to the suspension structure of the present invention, there is an advantage that variations due to accumulation of dimensional tolerances of each component can be absorbed without causing an increase in cost. In addition, a load caused by the variation in attachment is not applied to each shaft support means, and the rotational torque of the shaft support means can be reduced, thereby improving the durability.

  Hereinafter, a suspension structure according to an embodiment of the present invention will be described with reference to the drawings. Each of FIGS. 1 to 5 is a schematic diagram showing a suspension on the left side of a front wheel as a main configuration thereof, and FIG. 2 is a schematic exploded perspective view seen from the front, FIG. 2 is a schematic view seen similarly from the front of the vehicle, FIGS. 3 and 4 are both schematic views seen from the rear of the vehicle, and FIG. It is a schematic diagram which shows components. Although the present embodiment will be described using the left-side suspension of the front wheels, the suspension is configured symmetrically, and the right-side suspension is configured similarly to the left-side suspension. Will not be described.

As shown in FIGS. 1 to 3, this suspension mainly includes a strut 2, a knuckle (first member) 4, a lower arm 6, an upper housing (second member) 8, a lower housing (third member) 10, and a damper fork. (4th member) 20 is comprised.
The strut 2 is a member having both a function as a shock absorber (buffer device) and a function as a suspension arm (support), and supports the upper side of the knuckle 4 via an upper housing 8 described later. Here, the strut 2 itself is a known one, and a cylinder (not shown) is provided in a cylinder formed inside the strut outer cylinder, and the cylinder is filled with oil. When the input acts on the suspension, the input is buffered by moving the piston back and forth while receiving the resistance of the oil.

The knuckle 4 is a component that rotatably supports the drive shaft 18 and the hub (axle) 19, and has an upper end portion attached to the upper housing 8 and a lower end portion attached to the lower housing 10.
A knuckle arm 4a is formed on the knuckle 4, and a tie rod 12 is connected to the knuckle arm 4a. As a result, the steering force of the driver is transmitted from the steering gear box (not shown) to the knuckle 4 via the tie rod 12, so that the knuckle 4 rotates and the wheels are steered.

  Further, as shown in FIG. 4, a ball joint (second shaft support means) 14 is provided on the lower surface of the knuckle 4. The ball joint 14 is mainly composed of a spherical bearing portion 14a formed on the proximal end side and a stud portion (swinging shaft) 14b formed on the distal end side. Further, the stud portion 14b is formed in a tapered shape having a small diameter toward the tip, and a male screw is formed at the most distal portion.

The bearing portion 14a is rotatably embedded in the lower surface of the knuckle 4, and the stud portion 14b is attached so as to protrude downward.
On the other hand, a bearing (first shaft support means) 16 is provided above the knuckle 4. This bearing 16 also has a stud (oscillating shaft) 16b on the front end side where a male screw is formed. Further, as shown in FIG. 4, the stud portion 16b is formed in a tapered shape so that the diameter thereof becomes smaller toward the tip, and the stud portion 16b is configured such that the tip protrudes upward. The knuckle 4 is assembled in advance, the ball joint 14 is fastened by a pinch bolt 14c, and the bearing 16 is press-fitted into the knuckle 4 and integrated.

A line connecting the centers of the ball joint 14 and the bearing 16 is a kingpin axis (steering axis or steering axis) L _{KP of the} suspension.
The stud portions 16b and 14b are connected to the upper housing 8 and the lower housing 10, respectively, so that the knuckle 4 can be swingably held from above and below.

Among these, the upper housing 8 is fixed to the outer cylinder of the strut 2 by welding or the like in advance, and a boss portion 8 a for connecting the bearing 16 of the knuckle 4 to the vehicle outer side than the strut 2 is formed.
As shown in FIG. 4, the boss portion 8a is formed in a shape corresponding to the tapered shape of the stud portion 16b of the bearing 16. The stud portion 16b is inserted into the boss portion 8a and the upper portion thereof is formed by a nut 42. By fastening, the axis of the bearing 16 is aligned.

The lower housing 10 is also formed with a boss portion 10a having a shape corresponding to the taper shape of the stud portion 14b of the ball joint 14. By inserting the stud portion 14b into the boss portion 10a, the ball joint 14 Axis alignment is performed.
Moreover, as shown in FIGS. 1-3, the lower housing 10 is rotatably connected to the lower arm 6 via the volt | bolt 6c. The lower arm 6 includes a front base end portion 6a having a rotation center axis substantially along the longitudinal direction of the vehicle, and a rear side having a central axis in the vertical direction of the vehicle at the center side end portion (base end portion) of the vehicle. A base end portion 6b is provided, and bushes (not shown) are press-fitted into the base end portions 6a and 6b. Then, by inserting bolts along the central axes of these base end portions 6a and 6b and fastening them with nuts or the like, the lower arm 6 is attached to a vehicle body or a suspension frame (not shown) and the front base end portion 6a is rotated. Oscillation about the center axis of movement is allowed.

  On the other hand, a distal end side connection portion 6d having a central axis (that is, a central axis extending in the longitudinal direction of the vehicle) substantially parallel to the rotation center of the front base end portion 6a is also formed on the distal end side of the lower arm 6. A bush (not shown) is also press-fitted into the connecting portion 6d. As shown in FIG. 1, the lower housing 10 and the knuckle 4 are connected to the lower arm 6 so as to be movable up and down by fastening the connecting portion 6d and the lower housing 10 with bolts 6c.

  Further, as illustrated, the upper housing 8 and the lower housing 10 are connected via a damper fork 20. In this embodiment, the damper fork 20 includes a front damper fork 20f disposed in front of the drive shaft 18 and a rear damper fork 20r disposed in the rear of the drive shaft 18. These damper forks 20f and 20r are configured in substantially the same manner including the shape, and a bracket for connecting a stabilizer to the rear damper fork 20r is welded, and the front and rear damper forks 20f are also provided. , 20r are configured in the same manner except that they are symmetrically formed. Therefore, hereinafter, the two damper forks 20f and 20r are simply referred to as a damper fork 20 unless otherwise distinguished.

By the way, in this embodiment, the three constituent elements of the upper housing 8, the lower housing 10, and the damper fork 20 are integrated to function as one member, and an element obtained by integrating these three members is used. It is called support.
Here, it is conceivable that the support is integrally formed of aluminum or the like, but in the present embodiment, in consideration of cost, weight, and assembly workability, the upper housing 8, the lower housing 10, and the damper fork 20 are as described above. By dividing into three members and further dividing the damper fork 20 into two front and rear, it is supported while avoiding interference with the drive shaft 18 to ensure sufficient strength.

  In other words, if the support is an integrally molded product, the support is increased in size and weight in order to obtain sufficient rigidity, and the cost is increased. Further, the increase in weight increases the unsprung weight, which affects the operability. Furthermore, when the support is integrally molded, it is necessary to provide a hole for passing the drive shaft 18, but when the suspension is assembled, work for passing the drive shaft 18 through the support is required, and workability is reduced. To do.

Therefore, in this embodiment, the support is divided into the three components of the upper housing 8, the lower housing 10, and the damper fork 20, thereby reducing the weight and improving the assembling workability. It is.
Hereinafter, the damper fork 20 will be described. In the present embodiment, the damper fork 20 is formed by press-molding a sheet metal, and is formed to fasten the upper housing 8 as shown in FIG. The first and second bolt holes 24 and 26 and the third and fourth bolt holes 28 and 30 formed for fastening the lower housing 10 are provided.

Of the two bolt holes 24 and 26 formed at the upper side, the first bolt hole 24 on the vehicle outer side (side closer to the kingpin shaft L _KP ) serves as a reference hole during assembly work, and the upper housing 8 and When the lower housing 10 is assembled, the fastening operation is first performed using the reference hole (first bolt hole) 24. Therefore, the dimensional tolerance of the diameter of the reference hole 24 is managed so as to be within the minimum dimensional tolerance allowed for machining. As a result, when the bolt 32 (see FIGS. 1, 3 and 4) is inserted into the reference hole 24, there is no gap between the hole 24 and the bolt, and the reference position of the damper fork 20 is maintained. It is determined.

Further, the second bolt hole 26 on the vehicle inner side (the side far from the kingpin axis L _KP ) is formed in an elongated hole shape that is wide in the lateral direction. Specifically, the second bolt hole 26 is formed in the vertical direction (the axial direction of the kingpin axis L _KP ) with the minimum dimensional tolerance allowed for machining as in the case of the reference hole 24, while the second direction ( In the radial direction of the kingpin axis L _KP, the dimension is obviously larger than the hole diameter in the vertical direction. The horizontal hole diameter is set to about 1.2 times the vertical hole diameter, for example.

With this configuration, when the second bolt hole 26 is inserted through the bolt 34 (see FIG. 3 and FIG. 4), a tight situation with almost no gap in the vertical direction occurs. There will be a loose situation in which there will be gaps.
This is mainly for suppressing the displacement of the knuckle 4 in the kingpin axial direction. That is, as described above, in this embodiment, the ball joint 14 of the knuckle 4 and the stud portions 14b and 16b of the bearing 16 are formed in a tapered shape, and the knuckle 4 is connected to the upper housing 8 via the stud portions 14b and 16b. Although the stud portions 14b and 16b are formed in a tapered shape, it is convenient to adjust the axial center position with accuracy, but the dimensional accuracy in the kingpin axial direction is ensured. Will be difficult.

Therefore, as described above, for the first bolt hole 24 as the reference hole, the dimensional tolerance of the hole diameter is the minimum dimensional tolerance allowed by machining, and the second bolt hole 26 is in the kingpin axial direction. Is formed with the minimum dimensional tolerance allowed by machining as in the case of the reference hole 24, and in the radial direction of the kingpin axis L _KP , it is formed as a long hole by forming a dimension larger than the vertical hole diameter. is there.

Thereby, the dispersion | variation in the attachment position in a kingpin axial direction is controlled, and positioning accuracy improves. Further, the deviation in the kingpin radial direction caused by restricting the position in the kingpin axial direction is absorbed by the elongated hole shape of the second bolt hole 26.
On the other hand, the third and fourth bolt holes 28 and 30 formed below are set to have slightly larger hole diameters than the bolt diameters to be inserted. Specifically, the dimensional tolerance of the hole diameters of these bolt holes 28 and 30 is set to be relatively large, and is set to a dimensional tolerance larger than at least the dimensional tolerance of the reference hole 24.

As a result, variations or dimensional deviations caused by fastening in the first and second bolt holes 24 and 26 are absorbed by the dimensional tolerances of the third and fourth bolt holes 30.
Since the suspension structure according to an embodiment of the present invention is configured as described above, the procedure and operation of the assembly will be described as follows. First, the assembly procedure of the suspension will be described. The drive shaft 18 is inserted into the knuckle 4 in advance and the lower arm 6 is fastened with bolts. , 42.

  Then, the lower housing 10 and the upper housing 8 and the damper fork 20 are fastened with bolts. At this time, the bolts 32 and 34 are first passed through the first bolt hole 24 and the second bolt hole 26 to position the damper fork 20 with respect to the upper housing 8, and the bolts 36 and 36 are inserted into the third bolt hole 28 and the fourth bolt hole. The lower housing 10 is positioned with respect to the damper fork 20 through 38.

Next, the bolt 32 of the first bolt hole 24 is fastened with a nut 44, and then the bolt 34 of the second bolt hole 26 is fastened with a nut 46. Thereby, the damper fork 20 is attached to the upper housing 8 with high accuracy. Then, the bolts 36 and 38 passed through the third bolt hole 28 and the fourth bolt hole 30 are fastened with nuts 48 and 50. Thus, the axial and radial deviations of the kingpin shaft L _KP are absorbed by the second bolt hole 26, the third bolt hole 28, and the fourth bolt hole 30.

Therefore, the load caused by the variation in dimensional tolerance does not act on the ball joint 14 and the bearing 16, and the durability can be improved and the rotational torque can be reduced.
In addition, this suspension structure has the following effects when lateral force is input from the tire during vehicle travel. That is, as shown in FIG. 5, the input from the tire ground contact surface acts as a moment M around the second bolt hole 26 with the lower side of the damper fork 20 as the input point. In this case, the damper fork 20 can be regarded as a cantilever beam whose upper side is fixed, and the moment M acts as a moment for bending the damper fork 20 around the second bolt hole 26.

  However, as described above, the first bolt hole 24 is formed with a tight dimensional tolerance and the second bolt hole 26 is formed with a tight dimensional tolerance in the vertical direction. Can be prevented from shifting (or rotating). In addition, since the moment input is small in the vicinity of the third and fourth bolt holes 28 and 30, even if a gap is formed between the bolt and the hole, the above-described deviation can be prevented.

  As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited to the above-mentioned embodiment, A various deformation | transformation is possible. For example, in the above description, the case where the present invention is applied to a front suspension of a vehicle has been described. However, the present invention may be applied to a rear suspension. Moreover, you may apply a ball joint as a 1st axial support means. In the embodiment, the first bolt hole 24 is applied as the reference hole. However, any one of the first bolt hole 24 and the second bolt hole 26 may be applied to the reference hole. Also, other details can be variously modified without departing from the spirit of the present invention.

FIG. 2 is a diagram illustrating a configuration of a main part of a suspension structure according to an embodiment of the present invention, and is a schematic exploded perspective view of a suspension on the left side of a front wheel as viewed obliquely from the front of the vehicle. FIG. 3 is a diagram illustrating a configuration of a main part of a suspension structure according to an embodiment of the present invention, and is a schematic view of a suspension on the left side of a front wheel as viewed obliquely from the front of the vehicle. FIG. 2 is a diagram showing a main configuration of a suspension structure according to an embodiment of the present invention, and is a schematic view of a left-side suspension of a front wheel as viewed from the rear of the vehicle. FIG. 2 is a diagram showing a main configuration of a suspension structure according to an embodiment of the present invention, and is a schematic view of a left-side suspension of a front wheel as viewed from the rear of the vehicle. It is a mimetic diagram showing a damper fork as one part which constitutes the important section of a suspension structure concerning one embodiment of the present invention. It is a figure for demonstrating a prior art.

Explanation of symbols

2 Struts 4 First member (knuckle)
6 Lower arm 8 Second member (upper housing)
10 Third member (lower housing)
14 Ball joint (second shaft support means)
14b Oscillating shaft (Stud)
16 Bearing (first shaft support means)
16b Oscillating shaft (Stud)
18 Drive shaft 19 Hub (axle)
20 Fourth member (damper fork)
20f Front damper fork 20r Rear damper fork 24 1st bolt hole 26 2nd bolt hole 28 3rd bolt hole 30 4th bolt hole

Claims (2)

A first member that rotatably supports an axle of the vehicle;
A second member fixed to the strut of the vehicle and pivotally supporting the upper end side of the first member via first pivot support means;
A third member that pivotably supports the lower end side of the first member via a second pivot support means;
A sheet metal-like fourth member for fastening the first member and the second member with a bolt;
In the suspension structure formed in a tapered shape such that the swing shafts of the first and second shaft support means both have a small diameter toward the tip,
First and second bolt holes for fastening the second member and third and fourth bolt holes for fastening the third member are formed in the fourth member,
Of the first and second bolt holes, the tolerance of the hole diameter of the first bolt hole formed on the side close to the kingpin shaft connecting the centers of the swing shafts of the first and second shaft support means However, the second bolt hole formed on the side farther from the kingpin shaft is allowed in machining with respect to the kingpin axis direction. And has a vertical hole diameter with a minimum tolerance, and is formed into a long hole shape having a horizontal hole diameter larger than the vertical hole diameter with respect to the radial direction of the kingpin shaft,
The suspension structure, wherein the third and fourth bolt holes are formed with a tolerance larger than a tolerance of a hole diameter of the first bolt hole. The distal end side is swingably connected to the third member, and the base end side is further provided with a lower arm that is swingably connected to the vehicle. Suspension structure.

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