JPS6346743Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vibration-proof mount device for engine mounting that elastically supports an automobile engine.

[Conventional technology]

In the conventional anti-vibration mount device for engine mounting, the spring characteristics of the elastic member provided in the anti-vibration mount device are such that the compressive displacement increases monotonically as the compressive load increases, as shown in characteristic A in Fig. 1. It has become a characteristic of When the engine is installed, the elastic member is compressed and deflected to δ ₃ due to its own weight W _3. In the actual vehicle condition, the elastic member is subject to the load W ₃
Since it receives a variable load W ₁ or W ₂ centered on , the amount of deflection also varies by δ ₁ or δ ₂ centered on δ ₃ .

[The problem that the idea aims to solve]

This elastic member is desired to have a low spring constant that has a large vibration energy absorption effect in order to reduce vibration transmission and muffled _noise when the engine is idling. In order to lower the spring constant of , it is necessary to use a very soft elastic member. That is, an elastic member having characteristics as shown by curve B in FIG. 1 is required. However, if an elastic member with such characteristics is used, the deflection fluctuation range δ ₁ ′ to δ ₂ ′ with respect to the fluctuating load W ₁ to W ₂ becomes large, and the spring constant can be lowered, but on the other hand, the variation width due to the dead weight of the engine W ₃ A problem arises in that the deflection margin δ ₃ ' increases and the dispersion of the engine set position increases.
Further, even when a load fluctuation larger than the normal load fluctuation width W ₁ or W ₂ is applied, the engine is displaced along characteristic B, which causes interference between the engine and other parts. Furthermore, since a soft material is used for the elastic member, there is a problem that the durability of the elastic member is reduced.

The purpose of the present invention is to obtain a vibration-proof mount device having characteristics that can reduce the transmission of engine vibrations and reduce muffled noise without causing the above-mentioned inconvenient problems. has a low spring constant characteristic to keep the deflection when the engine is set to a minimum and efficiently absorb vibration energy in the range of normal load fluctuations centered on the engine's own weight, and It is an object of the present invention to provide a vibration-proof mount device which has a high spring constant characteristic to prevent excessive displacement of an engine, and which does not require the elastic member itself to be particularly soft.

[Means to solve the problem]

The anti-vibration mount device of the present invention, which meets this purpose,
In a vibration isolating mount device that supports an engine with an elastic member, the elastic member is a first elastic member that bends when a precompression load is applied and a load greater than the precompression load is applied to the vibration isolator mount device. , a second elastic member is provided in series with the first elastic member and bends when a load is applied to the vibration isolating mount device, and an elastic member is provided in parallel with the second elastic member and faces the second elastic member. A third member is provided with a gap that becomes zero when a load larger than the precompression load is applied to the vibration mount device, and is bent when a load greater than the load that causes this gap to become zero is applied to the vibration isolating mount device. It consists of an elastic member.

[Effect]

In the vibration-proof mount device configured in this way, when installing the engine, the second elastic member is first compressed and deformed, and when the load exceeds the pre-compression load applied to the first elastic member, The first elastic member is also compressed and deformed, and eventually reaches the load of the engine's own weight. Therefore, until the first elastic member is compressively deformed, the spring constant of the vibration isolating mount device is the spring constant of the second elastic member, and after the first elastic member starts compressively deforming,
The spring constant corresponds to that of connecting the first elastic member and the second elastic member in series, and the spring constant is significantly lowered. Furthermore, when a load greater than the engine's own weight is applied and the load becomes considerably large, the third spring provided in parallel begins to work, and the spring constant becomes large again. In other words, only within a certain load range around the engine load center,
The elastic members are operated in series to achieve a low spring constant, and for fluctuating loads that exceed a certain load range,
By increasing the spring constant by making the elastic members function singly or in parallel, it is possible to achieve a low spring constant characteristic with excellent vibration absorption effect within the normal load fluctuation range, and to reduce the displacement of the engine when exceeding that range. It is possible to obtain the ideal spring constant characteristic of a vibration-proof mount device, which is a characteristic of a high spring constant that is suppressed as much as possible. Furthermore, since the spring constant does not decrease until a load above a certain level is applied during engine installation, the deflection margin when the engine is installed is kept small, and variations in engine position during assembly are also reduced, resulting in vehicle quality. is stabilized.
Moreover, since such characteristics can be obtained by combining three elastic members without using a particularly soft elastic member, the problem of reduced durability of the elastic member itself does not occur.

〔Example〕

Preferred embodiments of the anti-vibration mount device of the present invention will be described below with reference to the drawings.

FIG. 2 shows a vibration-proof mount device according to a first embodiment of the present invention, with the upper side of the figure being the engine side and the lower side being the vehicle body side. The body side of the anti-vibration mount device is composed of a frame 1, and the frame 1 is attached to the body by mounting bolts 2 and 3 fixed to the frame 1. On the top surface of frame 1,
A first elastic member 4 having an annular cross section is provided, and the first elastic member 4 is made of rubber and is bonded to the upper surface of the frame 1. A frame 5 is provided on the upper surface of the first elastic member 4, and the lower surface of the frame 5 is bonded to the upper surface of the first elastic member 4.

An adjustment bolt 6 extending vertically is provided inside the annular portion of the first elastic member 4, and the adjustment bolt 6 is provided to penetrate the upper and lower frames 5, 1. The upper end of the adjustment bolt 6 is formed into a head 7 with an enlarged diameter, and the frames 1 and 5 are connected by the lower surface of the head 7 and a nut 8 screwed into the threaded part of the lower end of the adjustment bolt 6. They are tightened in a direction that reduces the distance between them. A cylindrical collar 9 is fitted into the adjustment bolt 6.
The frames 1 and 5 can be tightened until the collar 9 comes into contact with the lower surface of the head 7 of the adjustment bolt 6 and the upper surface of the frame 1. And frame bodies 1 and 5
are tightened in advance by adjusting bolts 6 and nuts 8 to a distance regulated by collar 9. Therefore, the first elastic member 4
A certain pre-compression load is applied to the first elastic member 4, and the first elastic member 4 is compressed and deformed by a certain amount in advance.
Note that 10 is a rubber-like elastic member bonded to the lower surface of the adjustment bolt head 7.

A frame 11 is provided on the upper surface of the frame 5, and the frame 11 is fixed to the frame 5 by appropriate means. A second elastic member 12 having an annular cross section is adhered to the upper surface of the frame 11, and the upper surface of the second elastic member 12 is attached to a frame provided at the upper end of the second elastic member 12. It is glued to the lower surface of body 1. Therefore, the member composed of the frame 1, the first elastic member 4, and the frame 5 and the member composed of the frame 11, the second elastic member 12, and the frame 13 have a laminated structure, First elastic member 4 and second elastic member 12
and are arranged in series. The material of the second elastic member 12 is also made of rubber. A mounting bolt 14 having a threaded portion extending upward is attached to the frame 13, and the frame 13 and the engine (not shown) are fixed by the mounting bolt 14.

A third elastic member 15 is provided inside the second elastic member 12 in an annular shape independently of the second elastic member 12 . Therefore, the third elastic member 15 and the second elastic member 12 are arranged in parallel.
The third elastic member 15 is bonded to the lower surface of the frame 13, and there is a certain amount of space between the lower end surface of the third elastic member 15 and the upper end surface of the adjustment bolt head 7 located below the third elastic member 15. A gap L is set. Therefore, the upper surface of the adjustment bolt head 7 has the function of applying a compressive force to the third elastic member 15 when the gap L is filled. The material of the third elastic member 15 is also made of rubber.

Note that 16 indicates a chamber space 17 defined by the frame 1, the first elastic member 4, and the frame 5, and the frame 1.
1. It is a communication hole that allows air to circulate between the chamber space 18 defined by the second elastic member 12 and the frame 13 and the outside.

The operation of the anti-vibration mount device of the present invention constructed as described above will be described below.

Before installing the engine, the first elastic member 4 includes:
A certain amount of precompression force adjusted by the collar 9 is applied, and the first elastic member 4 is compressively deformed by a certain amount. In this state, the engine is mounted on the upper part of the frame 13. Since the frame 1 is fixed to the body side, when the engine is mounted, a compressive load that pushes the frame 13 downward acts on the vibration-proof mount device. When a compressive load is applied to the frame 13, since a certain amount of compressive load is applied to the first elastic member 4 in advance, the compressive load applied to the frame 13 reaches this constant pre-compressive load. Until then, only the second elastic member 12 is compressively deformed. That is, as shown in FIG. 3, which shows the relationship between the compressive load W applied to the frame 13 and the displacement amount of the engine, that is, the displacement amount δ of the frame 13, the load W applied in advance to the first elastic member 4 is ₁ , the frame 13 is displaced up to δa along the amount of deformation of the second elastic member 12, and from point 0 to point a in FIG. 3.

When the compressive load W further increases and becomes a load of W ₁ or more, the first elastic member 4 as well as the second elastic member 12 starts to be compressively deformed, and eventually the engine's own weight
Leading to W ₃ . In a state where both the first elastic member 4 and the second elastic member 12 are compressed and deformed,
Since the first elastic member 4 and the second elastic member 12 are arranged in series, the spring constant of the vibration-proof mount device is significantly lower than when the second elastic member 12 is used alone. When the spring constant decreases, the increase in the displacement of the frame 13 with respect to the increase in the compressive load W becomes large, and the displacement exhibits characteristics such as from δa to δb, that is, from point a to point b, as the load W ₁ to W ₃ increases.

In the actual vehicle state, the load W fluctuates up and down around _W3 , but when the load W becomes larger than the engine's own weight _W3 and increases by a certain amount, the displacement of the frame 13 increases and eventually the frame 13 The gap L between the lower surface of the third elastic member 15 and the upper surface of the adjusting bolt head 7 becomes 0, and the state shown in FIG. 4 is reached. If a further load is applied from this state, the third elastic member 15 will also be compressed and deformed, and the third elastic member 15 will be compressed and deformed at the same time as the first elastic member 4.
Since it is arranged in parallel with the second elastic member 12, the spring constant of the vibration-proof mount device is greatly increased. Therefore, in Figure 3,
In the load region where the third elastic member 15 is brought into contact with the adjustment bolt 6 and the load W is ₂ or more, the characteristic line shows a sharp rise, and the margin of increase in δ for loads above point c, that is, above the displacement δc, is sharp. Become small.

In this way, in the anti-vibration mount device of the present invention, by combining the three elastic members, the spring characteristics of the anti-vibration mount device are as shown by the curve C in Fig. 3.
Compared to the conventional characteristic A in which there is only one elastic member, the spring constant becomes lower only in a certain load fluctuation range centered on the engine's own weight _W3 .

The characteristics of this spring constant are modeled and shown in FIGS. 5 and 6. The spring constant of the first elastic member 4 is
When k ₁ is the spring constant of the second elastic member 12, k ₂ is the spring constant of the third elastic member, and k ₃ is the spring constant of the third elastic member, the arrangement of each spring is as shown in FIG. The first elastic member 4 is compressed with a load _W1 in advance. As shown in FIG. 6, up to a load W ₁ , only the second elastic member 12 is deflected, and the spring constant as a vibration-proof mount device is k=k ₁ , and from a load W ₁ , the third elastic member 12 is deflected. Until the load W ₂ at which 15 starts to be compressed, the first elastic member 4 and the second elastic member 12 work in series, and the spring constant becomes k = (1/k ₁ + 1/k ₂ ) ^-1 ,
When the third elastic member 15 is applied with a load of _W2 or more, k=(1/ _k1 +1/ _k2 ) ^-1 + _k3 . Then, the characteristics are set so that the engine dead weight W ₃ is approximately in the middle of W ₁ and W ₂ . Setting this characteristic is
This is done by setting the initial compression force of the first elastic member 4 using the adjustment bolt 6 and setting the initial gap L in FIG. The spring model characteristics shown in Figure 6 are as follows: When each elastic member is made of rubber, the displacement-load characteristics are actually non-linear characteristics.
This results in an inverted S-shaped curve as shown in FIG.

In this way, by making the spring characteristics of the anti-vibration mount device into an inverted S-curve, in the actual vehicle condition after the engine is installed, the normal load fluctuation range centered on the engine's own weight W ₃ , that is, from point a in Fig. 3, can be adjusted. c.
Since the spring constant is set to be low within the range of the point, engine vibrations are effectively absorbed and muffled noise is reduced. Also, when installing the engine, load
Up to W ₁ , the spring constant can be set higher than the conventional one, so it can be set so that the deflection margin δb at engine weight W ₃ does not become large.
Variations in engine installation, etc. that occur when the deflection margin δb becomes large are also suppressed. In addition, beyond the normal load fluctuation range, that is, a
Since the spring constant is set high in the region where a variable load is applied below point c or above, excessive displacement is suppressed. Furthermore, such excellent spring constant characteristics can be obtained by simply combining the three elastic members 4, 12, 15 without using a particularly soft material for each elastic member 4, 12, 15. The problem of decreased durability of the elastic member when using a soft elastic member does not occur.

Note that since air from the chamber spaces 17 and 18 enters and exits through the communication hole 16, a damping effect due to air damping is obtained, and the damping effect of vibrations from the engine applied to the vibration-proof mount device is further promoted. In addition, the elastic member 10 attached to the lower surface of the adjustment bolt head 7 allows the adjustment bolt to be tightened when a force is suddenly applied to the first elastic member 4 in the tensile direction from the bent state as shown in FIG. Metallic contact between the lower surface of the head 7 and the frame 5 and generation of abnormal noise is prevented.

Next, FIG. 7 shows a vibration-proof mount device according to a second embodiment of the present invention. In this embodiment, a coil spring 19 is used as the first elastic member, and an initial compressive force is applied to the coil spring 19. In this way, each elastic member is not limited to being made of rubber, but may be made of any material that has a spring effect, and basically performs the same function as that shown in the first embodiment.

[Effect of idea]

As explained above, when using the vibration isolating mount device of the present invention, the second elastic member is provided in series with the first elastic member to which a certain initial load is applied, and the second elastic member is provided in parallel with the first elastic member to which a certain initial load is applied. By combining three elastic members, including the third elastic member with a gap, the load-displacement characteristics have an inverted S-shaped characteristic centered on the engine's own weight, so only the normal load fluctuation range exceeds that range with a low spring constant. It is possible to obtain ideal spring constant characteristics in which the region has a high spring constant. Due to this characteristic, there is no problem of uneven deflection during engine installation or a decrease in the durability of elastic members, and the low spring constant provides excellent engine vibration absorption and muffled noise reduction effects in the normal load range. The high spring constant can prevent excessive displacement of the engine in high load fluctuation areas.

[Brief description of the drawings]

Fig. 1 is a diagram showing the relationship between load and displacement of a conventional anti-vibration mount device, Fig. 2 is a vertical cross-sectional view of the anti-vibration mount device according to the first embodiment of the present invention, and Fig. 3 is a diagram of the relationship between the load and displacement of a conventional anti-vibration mount device. A diagram showing the relationship between load and displacement, Fig. 4 is a vertical cross-sectional view showing one state of the device in Fig. 2, Fig. 5 is a configuration diagram showing a model of the device in Fig. 2, and Fig. 6 is Fig. 5. FIG. 7 is a longitudinal cross-sectional view of a vibration-proof mount device according to a second embodiment of the present invention. 1, 5, 11, 13... Frame body, 4... First elastic member, 6... Adjustment bolt, 9... Collar, 12
... second elastic member, 15 ... third elastic member,
16...Communication hole, 19...Coil spring,
W ₃ ... Engine dead weight, k ₁ , k ₂ , k ₃ ... Spring constant.

Claims (1)

[Scope of utility model registration request] In a vibration isolating mount device that supports an engine with an elastic member, the elastic member is a first elastic member that bends when a precompression load is applied and a load greater than the precompression load is applied to the vibration isolator mount device. , a second elastic member is provided in series with the first elastic member and bends when a load is applied to the vibration isolating mount device, and an elastic member is provided in parallel with the second elastic member and faces the second elastic member. A third member is provided with a gap that becomes zero when a load larger than the precompression load is applied to the vibration mount device, and is bent when a load greater than the load that causes this gap to become zero is applied to the vibration isolating mount device. A vibration-proof mount device comprising an elastic member.