JPS645175B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention configures a dynamic damper by attaching a weight via an elastic member to a vibrating object that vibrates based on engine vibration, and The present invention relates to an improvement in a vibration damping device for an engine, which damps vibrations of a vibrating object.

(Prior art) Engine vibration damping devices include a dynamic damper in the main muffler, which is a vibrating object that vibrates based on engine vibration, as disclosed in, for example, Japanese Utility Model Application Publication No. 55-137212. There is something. This dynamic damper is roughly composed of an elastic member attached to the main muffler and a weight attached to this elastic member, and aims to attenuate the vibration of the main muffler by causing this dynamic damper to resonate. .

By the way, the temperature of the main muffler increases due to the heat of the exhaust gas passing through it. When the main muffler's temperature changes, its resonant frequency changes, and when the temperature of the dynamic damper changes, the elastic constants of the elastic members that make up the muffler change, so the dynamic damper changes as well. Damper resonance frequency changes.

Figure 1 is for explaining this.
In this figure, A shows a resonant frequency change curve of the main muffler with respect to temperature changes, and B shows a dynamic damper resonant frequency change curve with respect to temperature changes of the dynamic damper. What is the main muffler and dynamic damper?
As the temperature rises, the resonant frequency of both decreases, but the rate of decrease in the frequency of the dynamic damper's resonant frequency is greater than that of the main muffler. -10℃) to warm time (approximately 100℃)
However, the resonant frequency of the dynamic damper shows a drop of about 3.5 Hz from the cold time to the warm time.

A dynamic damper aims to reduce the vibration of the main muffler by bringing its resonant frequency as close as possible to the resonant frequency of the main muffler. Since the rate of change in the resonant frequency is larger than that of the main muffler, the resonant frequency of the dynamic damper and the resonant frequency of the main muffler will greatly deviate as the temperature rises.
There is a problem in that as the temperature of the dynamic damper increases, its vibration reduction efficiency decreases.

(Object of the Invention) The present invention has been made in view of the above circumstances, and is an engine vibration damping method that prevents the vibration reduction efficiency of a dynamic damper from decreasing as much as possible even if the temperature of the dynamic damper increases. The goal is to provide equipment.

(Structure of the Invention) A feature of the present invention is that a dynamic damper is provided with a correction means for correcting a dynamic damper resonance frequency that changes as the temperature of the dynamic damper changes.

(Example) An example of the engine vibration damping device according to the present invention will be described below based on the drawings.

2 to 6 show a first embodiment of the engine vibration damping device according to the present invention. In FIG. 2, 1 is a main muffler, 2 is an exhaust pipe, and 3
is a dynamic damper, and main muffler 1
is supported by the vehicle body via a hanger rubber 4, and 5 is a hanger which is welded to the main muffler 1. Here, the exhaust pipe 2 is a vibrating object that vibrates based on engine vibration, and the dynamic damper 3 is attached to this exhaust pipe 2. The dynamic damper 3 is roughly composed of a mounting member 4, a rubber 5 as an elastic member, and a weight (mass body) 6.
a is welded to the exhaust pipe 2. The rubber 5 and the weight 6 have a cylindrical configuration, and one end surface of the rubber 5 is attached to the mounting member 4, as shown in an enlarged view in FIG. A weight 6 is attached to the other end surface.

The dynamic damper 3 vibrates due to the vibration of the exhaust pipe 2, and as shown in FIG. A correction means 7 is provided for correcting the damper resonance frequency in a direction that suppresses the frequency drop. This correction means 7
Here, bimetal 8 is used as a thermally deformable member.
The bimetal 8 has a plate-like structure and is fixed to the mounting member 4 with screws 9. This bimetal 8 has arm portions 8a and 8b, and the arm portions 8a and 8b are configured to curve inward and face each other, and as the temperature of the dynamic damper 3 increases, As shown by the broken line in Figure 5, it is deformed outward. As the temperature of the dynamic damper 3 increases, the contact area of the arm portions 8a and 8b with the inner circumferential surface of the rubber 5 increases. As the temperature rises, a pressing force is applied from the inside to the outside of the bimetal 8.

In the dynamic damper 3, the contact area of the arms 8a and 8b of the bimetal 8 that contacts the rubber 5 increases as the temperature rises, thereby suppressing a decrease in the elastic constant of the rubber 5 and suppressing the rise in temperature. The accompanying frequency drop in the dynamic damper frequency is corrected, and as shown in FIG. By approximating the resonant frequency change curve C with respect to the temperature change of the exhaust pipe 2 as a vibrating object, even if the temperature of the dynamic damper 3 increases, the reduction in vibration reduction efficiency of the dynamic damper 3 is controlled. It is.

7 to 11 show a second embodiment of the engine vibration damping device according to the present invention.

In this FIG. 7, 10 is a radiator. Here, the radiator 10 is a weight that forms part of a dynamic damper. This radiator 10 is used to damp vertical vibrations of the vehicle body that vibrate based on engine vibrations. Reference numeral 11 denotes a frame that constitutes a part of the vehicle body. It is designed to be suspended via a . Bracket 12 includes figures 8 and 9.
As shown in the figure, a mount 13 as an elastic member
is installed. A fitting hole 13a is formed in the mount 13, a fitting projection 10a is formed in the radiator 10, and the fitting projection 10a is fitted into the fitting hole 13a. Mount 13 is
It has an attachment part 13b to the bracket 12 and an abutment part 13c to the radiator 10, and the columnar constriction part 1 is located between the attachment part 13b and the abutment part 13c.
It is 3D. A pair of bimetals 14 are provided on the back surface of the mounting portion 13b. As shown in FIG. 8, the bimetals 14 are provided on opposite sides of the columnar constrictions 13d, and as shown in FIG. 9, they extend parallel to each other along the direction in which the bracket 12 extends. It is said to be placed in This bimetal 14 has both ends 14a, 14a fixed to the mounting part 13b, and when the temperature of the bimetal 14 rises as the temperature of the radiator 10 rises, it changes from the cold state shown in FIG. The bimetal 14 is deformed, and as shown in FIG.
d is expanded to suppress a decrease in the elastic constant of the mount 13.

(Effects of the Invention) As explained above, in the present invention, a dynamic damper is provided with a correction means for correcting the frequency of the dynamic damper resonance frequency which changes with the temperature change of the dynamic damper. Even if the temperature of the dynamic damper increases, it is possible to prevent the vibration reduction efficiency of the dynamic damper from decreasing.

[Brief explanation of the drawing]

Figure 1 is a characteristic diagram showing the change in resonant frequency of a conventional engine vibration damping device with respect to temperature;
6 to 6 are diagrams showing a first embodiment of the engine vibration damping device according to the present invention, and FIG.
A perspective view showing the dynamic damper according to the present invention attached to an exhaust pipe, FIG. 3 is a cross-sectional view showing the configuration of main parts of the dynamic damper according to the present invention, and FIG. 4 is a perspective view showing the state in which the dynamic damper according to the present invention is installed. FIG. 5 is a partially enlarged sectional view of FIG. 3, and FIG. 6 is a diagram showing the temperature at the resonance frequency of the engine vibration damping device according to the present invention. 7 to 11 are diagrams showing a second embodiment of the engine vibration damping device according to the present invention, and FIG. 7 is a characteristic diagram showing changes in the weight of the dynamic damper according to the present invention. A perspective view showing the installation state when a radiator is used as a radiator, No. 8
The figure is a cross-sectional view showing the main part configuration of the radiator according to the present invention in an installed state. FIG. 11 is a diagram for explaining the operation of the second embodiment of the engine vibration damping device according to the present invention. 1...Main muffler, 2...Exhaust pipe, 3...
Dynamic damper, 5... Elastic member, 6... Weight, 7... Correction means, 8... Bimetal, 1
0...Radiator, 11...Frame, 12...
Bracket, 13...Mount, 14...Bimetal.

Claims (1)

[Claims] 1. A dynamic damper is constructed by attaching a weight via an elastic member to a vibrating object that vibrates based on engine vibration, and the dynamic damper is caused to resonate to damp the vibration of the vibrating object. The engine vibration damping device according to the present invention, further comprising a correction means for correcting a dynamic damper resonant frequency that changes as the temperature of the dynamic damper changes.