JPH068353Y2 - Anti-vibration support device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an anti-vibration support device used for a support portion of an optical pickup unit in a compact disc player for a vehicle.

[Technical background and problems]

FIG. 6 shows the main part of a compact disc player.

Reference numeral 1 in the figure is a support. This support 1 is a chassis of a compact disc player. An optical pickup unit 2, which is a main part of the player, an electronic circuit unit, a display mechanism, and an external connection connector mechanism (none of which are shown) are mounted on the chassis.

The base of the optical pickup unit 2 is a supported body 3, and the supported body 3 is supported on the support body 1 by a vibration isolation support device 4. In addition, a motor mechanism 5 for supporting and rotating the compact disc D on the supported body 3, a reading mechanism 6 facing the recording surface of the compact disc D in a non-contact manner, and the reading mechanism 6 along the disc. A guide mechanism 7 and the like for moving it are installed.

In the above compact disc player, the laser beam emitted from the objective lens 6a of the reading mechanism 6 is caused to follow the information track on the recording surface of the compact disc D to read digital information. A tracking servo device and a focusing servo device are provided in the reading mechanism 6, and the irradiation state of the laser beam is corrected by finely moving the objective lens 6a at a relatively high frequency. Therefore, the compact disc player
Directly receiving external vibration or shock will hinder the reading operation. That is, when the vibration from the outside is directly transmitted to the reading mechanism 6, the laser beam cannot be corrected, and an abnormality in information reading, for example, a skip of a performance sound occurs. Therefore, the anti-vibration support device 4 is used, and its anti-vibration function is used to absorb external vibrations.

However, recently, compact disc players have come to be mounted in automobiles. In this case, the anti-vibration support device 4 must be able to effectively anti-vibrate external vibration during driving of the vehicle.

Here, the relationship between the external vibration applied to the unit and the anti-vibration function of the anti-vibration support device when mounted on a vehicle will be described with reference to FIGS. 7 and 8.

In the vertical vibration of FIG. 6, due to the mass of the optical pickup unit 2 and the spring constant and the damping coefficient of the vibration isolation support device 4 itself, the vibration isolation support device 4 vibrates against vibration and impact. The behavior corresponding to several components is shown.

FIG. 7 is a graph showing the behavior of the anti-vibration support device 4 according to the frequency component due to the external vibration of the automobile. The vertical axis represents the vibration transmissibility. What is vibration transmissibility?
The ratio of the acceleration transmitted to the supported body 3 to the acceleration due to the vibration or shock of the support 1 is shown. Also,
The horizontal axis shows the frequency.

The first resonance frequency is indicated by ₀ in FIG. 7. The range indicated by I is an amplification area where the vibration transmissibility is 1 or more, and the range indicated by II is a vibration isolation area where the vibration transmissibility is 1 or less. In the vibration isolation region of II, external vibration is reduced and transmitted to the supported body 3, and the vibration isolation effect can be obtained.

Next, of the external vibrations that act when the compact disc player is mounted on an automobile, the characteristics of vertical vibrations will be described with reference to FIG. The vertical axis of FIG. 8 represents the magnitude of acceleration due to vibration or shock, and the horizontal axis represents the frequency.

A in FIG. 8 shows the vertical vibration acceleration of the automobile. According to this graph, II around 6 to 10 Hz and around
The acceleration of vibration is low in the frequency range shown by I, and the acceleration of vibration is high at higher frequencies. Therefore, it is effective to set the vibration isolation region II shown in FIG. 7 to a range of higher frequencies than the low frequency region III and the amplification region I to a small acceleration region III. The anti-vibration effect will be obtained.

Also, focusing on the vibration transmissibility, even if the amplification region I of FIG. 7 is set in the small acceleration range III of FIG. 8, if the vibration transmissibility at the primary resonance frequency ₀ part is high, In the range of III, the effective vibration damping effect is not achieved, and the external vibration of A is amplified and transmitted to the supported body 3. In that case, the degree of displacement of the supported body 3 becomes large, which causes inconvenience such as hitting another portion. Therefore, the vibration transmissibility in the region III is kept within a certain range so that the limit input acceleration of the optical pickup unit 2 shown by B in FIG. 8 does not overlap with the vertical vibration acceleration of the automobile A in the region III. Must be set to.

To summarize the above, the following conditions are required as the characteristics of the vibration isolation support device 4 used for the on-vehicle optical pickup unit.

(a) The amplification area I in FIG. 7 is set to be within the area III in FIG. For that purpose, the primary resonance frequency _{0 is set} to a low frequency region (about 7 to 9 Hz in the example of FIG. 8).

(b) In the amplification region I set in the range of III, the vibration transmissibility is lowered so that the vertical vibration acceleration (graph of A) of the automobile does not reach the limit input acceleration (graph of B) of the optical pickup unit. . For that purpose, the damping coefficient of the vibration system in the anti-vibration support device 4 must be increased to some extent.

Conventionally, an elastic body such as a coil spring or solid rubber that is generally considered as the vibration isolation support device 4 is
Lowering the amplification region indicated by the next resonance frequencies ₀ and I is nothing but reducing the spring constant of the elastic body itself to make it soft. However, there is a characteristic that the vibration transmissibility in the amplification region I becomes high only by lowering the spring constant of the coil spring or the like and making it soft. That is, a soft coil spring or the like easily resonates with a large amplitude with respect to external vibration. Therefore, it is impossible to satisfy the above conditions (a) and (b) at the same time with a simple coil spring or the like, and it cannot be used in a compact disc player for a vehicle or the like.

The present invention solves the above-mentioned conventional problems, and the amplification region near the resonance frequency can be set to a desired frequency region,
Moreover, it is an object of the present invention to provide an anti-vibration support device capable of reducing the transmissibility of vibration acceleration in this region.

[Means for solving problems]

The anti-vibration support device according to the present invention includes a bag body formed of a film connecting a portion attached to a support body and a portion attached to a supported body, a coil spring surrounding the bag body, and Having a high-viscosity fluid sealed in the bag, a static load applied from the supported body is supported by the coil spring as a load in the compression direction,
The film of the bag body has a bending margin when the supported body is supported by the coil spring in a static load state.

[Action]

In the above means, the static load of the supported body is supported by the coil spring as a compressive load. The primary resonance frequency is set in a desired frequency range by the spring constant and the load of the coil spring. Further, the bag body having a bending allowance in the state where the coil spring receives a static load and in which a highly viscous fluid is sealed inside reduces the transmissibility of vibration acceleration. As a result, the acceleration of external vibration is attenuated in the vicinity of the resonance frequency band set by the coil spring.

[Example of device]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. Each of the drawings is a cross-sectional view showing an anti-vibration support device according to the present invention in each embodiment.

FIG. 1 shows the most basic first embodiment.

This anti-vibration supporting device is used for supporting an optical pickup unit in a vehicle-mounted compact disc player.

Reference numeral 1 in FIG. 1 is a support such as a chassis of the same compact disc player as that shown in FIG. 6, and 3 is a support such as a base in the optical pickup unit 2.

This vibration isolation support device has a first rubber member 11, a second rubber member 12, a third rubber member 13, and a coil spring 14 which is an elastic member having a predetermined spring constant.

A groove 11a is formed at the lower end of the first rubber member 11, and this portion is fitted to the support 1. Similarly second
The rubber member 12 is also formed with a groove 12a, and this portion is fitted in the portion of the protruding portion 3a of the supported body 3.

A thin film 11b is integrally formed on the first rubber member 11. The second rubber member 12 has a hollow portion 1 inside.
2c, and the thin film 12 is provided at the lower end of the hollow portion 12c.
b is integrally formed. First rubber member 11 and second
The rubber members 12 are adhered to each other at their joints E. As a result, the thin bag 11b and the thin film 12b form a hollow bag. Highly viscous fluid rubber, such as silicone oil, is enclosed in this bag.
Further, the third rubber member 13 and the second rubber member 12 are adhered to each other by the joint surface F. A hole 13a is formed in the third rubber member 13, and the second rubber member 1
It communicates with the two hollow portions 12c.

The coil spring 14 is provided so as to surround the thin film 11b, and both ends thereof are in contact with the supporting surfaces 11c and 11d of the first rubber member 11. FIG. 1 shows a stationary state. In this state, the static load of the optical pickup unit 2 (see FIG. 6) acts on the vibration-isolating support member, particularly the coil spring 14, via the supported body 3. There is. Therefore, in the static load supporting state of FIG. 1, the coil spring 14 is vertically shorter than its free length and contracted in the vertical direction. In this static load supporting state, the thin film 11b of the first rubber member 11 has a bending margin so as to expand in the circumferential direction, and similarly, the thin film 12b of the second rubber member 12 is provided.
Also has a bending allowance so as to have a wavy shape.

Further, both the upper and lower rising portions G and H of the thin film 11b of the first rubber member 11 are formed into curved surfaces.

Next, the operation will be described.

In this anti-vibration support device, the coil spring 14 mainly receives a static heavy load, and the liquid rubber 15 alone does not have a rigidity sufficient to receive a static load. Therefore, the spring constant of the entire vibration isolation support device is mainly determined by the coil spring 14
It is determined by its spring constant. In a vehicle, the primary resonance frequency ₀ shown in FIG. 7 is within the range of III in FIG. 8, that is, the vibration is relatively small in consideration of the spring constant and the static load on the supported body 3. Set it so that it falls within the frequency range. Therefore, the coil spring 14 has a relatively low rigidity (soft one). Since the soft coil spring 14 alone has a large transmissibility for vibration, the transmissibility of vibration can be reduced by the structure of the bag body made of the thin films 11b and 12b and the liquid rubber 15 inside thereof.

As described above, since the soft coil spring 14 is used, the primary resonance frequency ₀ and the amplification region I
Is in the area III in FIG. 8 and the image stabilization area II is the above III
It is set so that the frequency range is higher than the region. Therefore, when this anti-vibration support device is mounted on a vehicle and travels, the anti-vibration support device is effective in the high frequency range of 20 Hz or higher where the vibration acceleration is high (the frequency range is higher than the III region). Anti-vibration, optical pickup unit 2
The amount of vibration transmitted to the machine is reduced.

Further, when subjected to vibration at the same time, the liquid rubber 15 in the bag body moves up and down, the thin film 12b moves up and down, and the thin film 11a moves in the circumferential direction. Since the energy of vibration is absorbed by this movement, the vibration acceleration is reduced and the transmissibility of the vibration acceleration is reduced. Therefore, the transmissibility of vibration acceleration in the primary resonance point ₀ and the amplification region I shown in FIG. 7 also becomes small. As a result, in the low frequency region III of FIG. 8, the vibration acceleration of the vehicle shown by the graph A does not reach the limit input acceleration of the optical pickup unit shown by B, and the pickup due to the vibration of the low frequency region III occurs. Is within the limit.

Therefore, the optical pickup unit 2 shown in FIG. 6 operates normally irrespective of the vibration of the vehicle body, and the skipping phenomenon of playing sounds does not occur.

Since the thin film 11b rises in a curved shape at the G and H portions, the G and H portions can exert elastic supporting force against the vibration in the left-right direction in FIG. There is.

Next, FIG. 2 shows a second embodiment.

This embodiment shows a structure in which the support 1 is a concave frame. The structure of the anti-vibration supporting device provided between the support 1 and the supported body 3 is the same as that shown in FIG. In the second embodiment, a damper 16 made of urethane rubber or the like is attached to the inner surface of the support 1. The vibration isolating support device shown in FIG. 1 can also absorb the vibration in the left-right direction in the figure, but when it hits the inner surface of the support body 1 due to a large vibration, the damper 16 absorbs the impact. There is.

FIG. 3 shows a third embodiment.

This embodiment differs from the first embodiment in that the second rubber member 12
The thin film 12d is provided substantially in the center of the hollow portion 12c. A fourth rubber member 21 is provided at the boundary between the first rubber member 11 and the second rubber member 12, and an orifice 21a is formed in this rubber member 21. Due to the presence of the orifice 21a, the transmissibility of acceleration of vertical vibration in the drawing is further reduced. That is,
When the bag body formed by the thin films 11a and 12d repeatedly oscillates and contracts by vibrating in the vertical direction and changing the distance between the support body 1 and the supported body 3, the liquid rubber 15 causes the orifice 21a to move each time. Will pass through. When the liquid rubber 15 passes through the orifice 21a, the flow velocity and the pressure are changed, and further, the heat quantity is changed, and the vibration energy is largely absorbed. Therefore, the acceleration of the vertical vibration is absorbed, and the vibration transmissibility becomes small. Therefore, the vibration transmissibility can be reduced even in the amplification region I of FIG. 7, and the safety factor between the vibration acceleration of A of FIG. 8 and the limit input acceleration of B of FIG. It gets even higher.

FIG. 4 shows a fourth embodiment.

In this embodiment, the pillar 11c is provided at the center of the first rubber member 11.
Is integrally provided, and the pillar 11c is the liquid rubber 15
Are intervening in. By providing this column 11c, it is possible to effectively reduce the vibration in the left-right direction in the drawing. That is, when subjected to vibration in the left-right direction of the figure,
The liquid rubber 15 moves left and right. At this time, the pillar 11
c serves as resistance against the movement of the liquid rubber 15. Pillar 1
1c itself is also deformed by receiving a force from the liquid rubber 15. Therefore, the energy of vibration in the left-right direction is converted into the kinetic energy and thermal energy of the liquid rubber 15 and the elastic energy of the column 11c, and the vibration acceleration is reduced.

FIG. 5 shows a fifth embodiment.

This embodiment corresponds to a combination of the third embodiment and the fourth embodiment, and both the orifice 21a and the column 11c are provided in the bag body. In this embodiment, the transmissibility of both vertical and horizontal vibration accelerations can be reduced.

In the embodiment shown in FIGS. 3 to 5, a damper 16 as shown in FIG. 2 may be provided.

Further, the anti-vibration support device can be used not only as a support mechanism for an optical pickup unit but also for other vehicle-mounted equipment and other equipment.

[Effect of device]

According to the present invention described above, the following effects can be obtained.

(1) Since the static load of the supported body is received by the coil spring, the resonance frequency can be set in a desired band by the spring constant and the load of the coil spring.

(2) Since the highly viscous fluid is enclosed in the bag body having a bending allowance while the coil spring receives a static load, the transmissibility of vibration acceleration can be reduced even in the above-mentioned band.

(3) Since it is composed of the bag body and the coil spring surrounding the bag body, it becomes a small vibration-proof support device.

(4) The bag body can absorb not only the vibration of the supported body in the load direction but also the vibration energy of the other direction.

[Brief description of drawings]

1 to 5 are cross-sectional views showing an anti-vibration support device according to the present invention by embodiment, FIG. 6 is a schematic view showing a main part of a compact disc player as an example of use of the anti-vibration support device, and FIG. FIG. 8 is a diagram showing the behavioral characteristics of the anti-vibration support device, and FIG. 8 is a diagram showing the characteristics of vertical vibration of the automobile. 1 ... Supporting body, 3 ... Supported body, 11, 12, 13 ...
Rubber member, 11b, 12b, 12d ... Thin film forming bag body, 14 ... Coil spring (elastic member), 15 ...
… Liquid rubber.

Claims (1)

[Scope of utility model registration request] 1. A bag body formed of a film for connecting a portion attached to a support body and a portion attached to a supported body, a coil spring arranged so as to surround the bag body, and sealed in the bag body. And a static load applied from the supported body is supported by the coil spring as a load in the compression direction, and the film of the bag body is in a static load state of the supported body by the coil spring. An anti-vibration support device, characterized in that it has a bending margin when it is supported by.