JPH0444409Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a suspension device for a vehicle that includes a lateral rod installed between an axle case and a vehicle body to prevent lateral vibration of the vehicle body.

(Prior Art) As a conventional suspension device, a device as described in, for example, Japanese Patent Application Laid-open No. 85027/1983 is known.

As shown in FIG. 5, this conventional device includes an axle case 100 housing a differential gear therein, a lateral bracket 101 fixed to the axle case 100, and a cantilever supported by the lateral bracket 101. solid pin 102,
a lateral rod 104 whose one end is attached to the solid pin 102 via a rubber bushing 103;
and a weight 105 provided at the tip of the solid pin 102.

In this conventional device, the vibration generated by the meshing force of the differential gear is amplified by the axle case 100, and further by the lateral rod 10.
In order to reduce cabin noise (differential noise) that is transmitted to the vehicle body via the lateral rod 104, the weight 105 is provided at the tip of the solid pin 102 to which one end of the lateral rod 104 (the axle case 100 side) is attached. The weight 105 is used to bring the vibration node to the solid pin 102, thereby reducing the level of vibration transmitted from the lateral rod 104 to the vehicle body.

(Problem to be solved by the invention) However, in such a conventional device, one end of the lateral rod 104 is connected to the solid pin 1.
Solid pin 1 by attaching it to 02
02 itself has elasticity, the solid pin 102 is a spring system, and the weight 105 is a mass body to generate elastic vibration, and the resonance of the solid pin 102 due to this elastic vibration becomes the bending and torsion resonance frequency of the axle case 100. This causes a problem in that the elastic vibration of the solid pin 102 itself becomes an amplification component and worsens the differential noise.

(Means for solving the problem) The present invention was made with the purpose of solving the above-mentioned problems, and to achieve this purpose, the present invention incorporates a differential gear inside. The suspension device includes an axle case housed in the axle case, a lateral bracket fixed to the axle case, and a lateral rod having one end attached to the lateral bracket via a pin and the other end attached to the vehicle body. The pin is a hollow pin, and the pin resonance frequency determined by the mass and elasticity of the hollow pin is set to a high frequency range outside the bending resonance frequency range and torsional resonance frequency range of the axle case.

(Function) Therefore, in the suspension device of the present invention, as described above, by attaching one end of the lateral rod to the hollow pin, the pin mass of the hollow pin is smaller than that of the solid pin, and the hollow The pin resonance frequency determined by the mass and elasticity of the pin is set to a high frequency range outside the bending resonance frequency range and torsional resonance frequency range of the axle case.

As a result, when vibrations generated by the meshing force of the differential gear are transmitted to the vehicle body via the axle case and the lateral rod, amplification of the transmitted vibrations due to the elastic vibrations of the hollow pin itself is suppressed.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
In describing this embodiment, we will take as an example a 5-link type rear suspension device that includes a lateral rod, and the first suspension shown in FIGS.
The configuration of the embodiment will be explained.

A is a rear suspension device, and as shown in FIG. 1, it includes a rear axle case 1, lower links 4, 4', upper links 6, 6', coil springs 7, 7', and shock absorbers 9, 9'. , a lateral rod 10, a lateral bracket 11, a hollow bolt 12, and a cylindrical bracket 15.

The rear axle case 1 houses the differential gear in the center, and the left and right tubes house the drive shaft 2 from the differential gear.
2' is interpolated.

Incidentally, brake drums 3, 3' are provided at the ends of the drive shafts 2, 2'.

The lower links 4, 4' have rear ends supported by the rear axle case 1, and front ends supported by the vehicle body via lower link brackets 5, 5'.

The upper links 6, 6' are the lower links 4,
4', the rear end is supported by the rear axle case 1, and the front end is supported by the vehicle body.

The lower ends of the coil springs 7, 7' are attached to the axle case 1, and the upper ends (where the spring seats 8, 8' are provided) are attached to the vehicle body.

Like the coil springs 7, 7', the lower ends of the shock absorbers 9, 9' are supported by the rear axle case 1, and the upper ends are supported by the vehicle body.
The load in the vertical direction of the vehicle is supported by the coil springs 7, 7' and the shock absorbers 9, 9'.

The lateral rod 10 is placed in a horizontal position almost parallel to the rear axle case 1, with one end attached to the rear axle case 1 and the other end attached to the vehicle body, and this lateral rod 10 mainly supports the load in the lateral direction of the vehicle. , Lateral vibration (hip shake)
This is provided to prevent this.

The lower links 4, 4' and upper links 6, 6', which mainly support the load in the longitudinal direction of the vehicle, and the lateral rod 10, which mainly supports the load in the lateral direction,
A link is constructed.

The lateral bracket 11 is fixed to the rear axle case 1 in order to attach the lateral rod 10 to the rear axle case 1, and the lateral bracket 11 has a support plate for supporting a hollow bolt 12 as a pin on both sides. The portions 11a and 11b are fixed in parallel to each other.

The hollow bolt 12 is attached to the lateral bracket 1
Through-hole 1 opened in support plate portions 11a and 11b of 1
1c and 11d, this hollow bolt 12 is attached to the threaded portion 12a side with a nut 14 screwed together via a washer 13 so as to be supported on both sides.

The cylindrical bracket 15 is connected to the lateral rod 1.
0, and is attached to the hollow bolt 12 via a rubber bush 16.

Next, the operation of the first embodiment will be explained.

First, differential noise occurs because vibrations generated by the force of meshing the differential gears are amplified in the rear axle case 1, and this amplified vibrations are transmitted to the vehicle body through the lateral brackets 11 and lateral rods 10. The resulting differential noise is the main one, and if there is a factor that amplifies the vibration in the vibration transmission path, the differential noise will further worsen.

Regarding this point, as is clear from the description in Japanese Patent Application Laid-open No. 50-85027, the factor that most amplifies vibration is the elastic vibration of the hollow bolt 12 itself at the mounting portion of the lateral rod 10 on the rear axle case 1 side. It is.

On the other hand, in the first embodiment, when compared with a solid bolt, the decrease in bolt mass is large and the decrease in bending rigidity is relatively small, so that the hollow bolt 12
The resonance point of the rear axle case 1 can be set in a high frequency range outside the bending and torsional resonance regions of the rear axle case 1.

Therefore, in order to clarify the above-mentioned resonance point shift, the natural circular frequency of the bolt will be explained.

Generally, the natural circular frequency w is expressed by the following equation.

ν; Natural angular frequency l; Length E; Longitudinal coefficient ρ; Density A; Cross-sectional area J; Moment of inertia of area Here, a hollow bolt and a solid bolt having the same outer diameter will be compared.

When the outer diameter of the hollow bolt and the solid bolt is d ₀ and the inner diameter of the hollow bolt is d ₁ , the natural circular frequency wj of the hollow bolt and the natural circular frequency wi of the solid bolt are expressed by the following equations.

Therefore, the ratio wj/wi of the natural circular frequency wj of the hollow bolt to the natural circular frequency wi of the solid bolt is expressed by the following formula, and as is clear from the graph in Figure 3, it is a value larger than 1. Hollow bolts can have a higher resonance frequency than solid bolts.

For example, if you compare a hollow bolt with an outer diameter of 20 mm and an inner diameter of 14 mm, and a solid bolt with an outer diameter of 20 mm,
wj/wi≒1.22, and the bending resonance frequency of the hollow bolt can be 1.22 times that of the solid bolt.
When the frequency is 1000Hz, the frequency can be increased by 200Hz or more.

Next, when comparing a bolt supported on both ends and a bolt supported on a cantilever, the bolt mass remains the same, but when looking at the bending rigidity, the case of support on both ends is significantly higher than that of cantilever support. Accordingly, the frequency of the resonance point can also be significantly increased.

Therefore, in the first embodiment, since the hollow bolt 12 is fixed to the lateral bracket 11 in a supported state on both sides, the resonance point of the hollow bolt 12 itself can be set in a higher frequency range.

Next, a second embodiment shown in FIG. 4 will be described.

This embodiment is an example in which a hollow bolt 12 as a pin is fixed vertically in a vertically supported state, and the hollow bolt 12 and nut 14 are fixed to the upper and lower support plate parts 11e and 11f of the lateral bracket 11.
is installed.

Note that the other configurations are the same as in the first embodiment, so
The same reference numerals are given to the drawings, and the description thereof will be omitted.

Furthermore, since the operation is similar to that of the first embodiment, the explanation will be omitted.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, the shape of the lateral bracket can be modified in many ways in addition to the embodiments, and in short, it only needs to have a shape that can support a hollow pin (such as a hollow bolt).

Further, in the embodiment, an example was shown in which the hollow bolt was supported on both sides, but it may be supported on one side.

Also, a mass may be added to the hollow pin to shift the resonance point and reduce the level of vibration caused by interference.

(Effect of the invention) As explained above, in the suspension device of the present invention, as stated in the claims, the axle case side of the lateral rod is attached to the hollow pin, and the hollow pin The pin resonance frequency, which is determined by the mass and elasticity of the pin, is set to a high frequency range that is outside the bending resonance frequency range and torsional resonance frequency range of the axle case. When the vibration is transmitted to the vehicle body via the hollow pin, the transmitted vibration is not amplified by the hollow pin, resulting in the effect that the noise inside the vehicle can be reduced.

[Brief explanation of the drawing]

Fig. 1 is an overall perspective view showing the suspension device of the first embodiment of the present invention, Fig. 2 is a sectional view showing the main parts of the device of the first embodiment, and Fig. 3 is a natural circle of a solid bolt and a hollow bolt. A graph showing the ratio of vibration frequencies, FIG. 4 is a cross-sectional view showing the main parts of the second embodiment device, and FIG. 5 is a cross-sectional view showing the main parts of the conventional suspension device. 1...Rear axle case (axle case),
10...Lateral rod, 11...Lateral bracket, 12...Hollow bolt (hollow pin).

Claims (1)

[Scope of Claim for Utility Model Registration] An axle case in which a differential gear is housed, a lateral bracket fixed to the axle case, one end attached to the lateral bracket via a pin, and the other end attached to the lateral bracket. In a suspension device equipped with a lateral rod attached to the vehicle body, the pin is a hollow pin, and the pin resonance frequency determined by the mass and elasticity of the hollow pin is outside the bending resonance frequency range and torsional resonance frequency range of the axle case. A suspension device characterized by being set in a high frequency range.