JP2005030600A - Vibration damping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration damping device having a smaller longitudinal dynamic spring constant and effectively reduced noises in a room during acceleration or high speed travel. <P>SOLUTION: The vibration damping device comprises a cylindrical body fitting 1 to be fixed to a body side, a boss fitting 2 to be connected to a vibration generator side, a rubber elastic body 3 as a vibration damper laid between both of these, front and rear stopper rubber portions 51, 52 attached to a connection member 4 to be fixed to the boss fitting 2 or its upper part, and stopper members 7 arranged at the front and rear parts of the stopper rubber portions 51, 52 and fixed to the body side. At least one of the front and rear stopper rubber portions 51, 52 has a small cavity 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vibration isolator for mainly supporting a vibration unit such as a power unit such as an automobile engine.

  A rubber elastic body as a vibration isolator between a vibration generator member and a vehicle body member as a vibration isolator for supporting a vibration generator such as an automobile engine so that the vibration is not transmitted to the vehicle body etc. A non-liquid-enclosed body that attenuates vibration using only the characteristics of the rubber elastic body, with the basic structure of the vibration generating body side member being vibration-proofly supported by the rubber elastic body. There have been proposed vibration isolators having various structures such as a liquid sealing type in which a liquid is sealed inside and a liquid flow effect of an orifice is used (for example, Patent Document 1-2 below).

The vibration isolator of FIG. 6 is a vibration isolator according to a comparative example that can be used so as to support a power unit such as an automobile engine on its side, and a cylindrical main body 101 fixed to the vehicle body side. As a vibration isolator interposed between the boss fitting 102 and the boss fitting 102, which is disposed slightly above the shaft center portion and connected to the vibration generating body side, and the cylindrical body fitting 101 and the boss fitting 102. A rubber elastic body 103, a connecting member 104 of a vibration generating body fixed to the upper portion of the boss fitting 102, a stopper rubber 105 attached to the connecting member 104, and a front and rear portion of the apparatus fixed to the vehicle body side. And an arch-shaped stopper member 107 disposed at a front and rear portion and an upper portion with respect to the stopper rubber 105, and the vibration from the engine is elastic. With absorbed attenuated by 103, the stopper rubber 105 by contact with the stopper member 107, is configured to regulate the large displacement in the back-and-forth direction and upward.
JP-A-10-220508 JP 2001-280404 A

  By the way, in the vibration isolator having the above structure, the front and rear rubber parts 151 and 152 of the stopper rubber 105 abut against the stopper member 107 with respect to the front-rear direction displacement on the vibration generating body side, so Although the stopper rubber 105 abuts against the stopper member 107 during traveling, the dynamic spring constant in the front-rear direction tends to be high, and the vibration mainly having a relatively small amplitude. There is a dislike that the damping effect on can not be sufficiently obtained.

  In particular, when the vehicle is accelerated or when the engine rotates at a high speed of 2500 rpm to 4000 rpm, the connecting member 104 on the vibration generator side is displaced rearward, and the rubber portion 152 on the rear side of the stopper rubber 105 is moved relative to the stopper member 107. And remain in contact. Therefore, when a vehicle such as an automobile is accelerated or traveling at high speed, vibration and noise on the vibration generating body side are easily transmitted to the vehicle body side, and the noise in the room increases.

  On the other hand, changing the characteristics of the stopper rubber 105 by changing the material such as the elastic force may reduce the spring force at the time of the stopper action and impair the stopper action and durability.

  That is, in the above-mentioned vibration isolator, the initial contact of the stopper rubber 105 with the stopper member 107 is relatively soft, the dynamic spring constant in the front-rear direction can be reduced, and the stopper action can be ensured. It is also desirable to be able to suppress noise transmission to the vehicle body during vehicle acceleration and high speed travel.

  The present invention has been made in view of the above, and in the vibration isolator having the above-described stopper structure, the anti-vibration device capable of reducing the dynamic spring constant in the front-rear direction without affecting the characteristics such as durability and stopper action. It is an object of the present invention to provide a vibration isolator and further a vibration isolator capable of effectively reducing indoor noise during acceleration and high speed running.

  The present invention solves the above-mentioned problem, a cylindrical first metal fitting fixed to the vehicle body side, a second metal fitting arranged slightly above the shaft center portion and connected to the vibration generator side, Front and rear attached to a connecting member between a rubber elastic body interposed between the first metal fitting and the second metal fitting and an upper portion of the second metal fitting or a vibration generating body fixed to the upper portion of the second metal fitting. And a stopper member in the front-rear direction that is disposed on the front and rear sides of the stopper rubber portion and fixed to the vehicle body side, and the stopper rubber portion and the stopper member prevent the front-rear direction from acting. The vibration device is characterized in that a small cavity is provided in at least one of the front and rear stopper rubber portions. The small cavity is particularly preferably provided at least in the stopper rubber portion on the rear side.

  According to this vibration isolator, the load of the vibration generating body is supported by the rubber elastic body as the vibration isolating body via the second metal fitting so that the vibration is not transmitted to the vehicle body or the like. In this state, the front and rear stopper rubber portions come into contact with the stopper member with respect to the vibration displacement in the front and rear direction on the vibration generating body side when the vehicle travels, thereby achieving a front and rear direction stopper action. In particular, in the case of the present invention, since a small cavity is provided in at least one of the front and rear stopper rubber portions, the stopper rubber portion is easily elastically deformed up to a certain amplitude range. Becomes softer.

  As a result, the dynamic spring constant in the front-rear direction can be reduced, and good vibration isolation characteristics can be exhibited against vibrations having a relatively small amplitude. This effect is particularly remarkable when small cavities are provided in both the front and rear stopper rubber portions. Moreover, during vibrations with large amplitudes, the small cavity is crushed and the wall surface of the small cavity is brought into close contact with each other, so that the spring force as a stopper is increased, the stopper function is as good as before, and the durability is also kept good. it can.

  In particular, when a small cavity is provided in at least the rear stopper rubber part, when the vehicle is accelerated or when the engine rotates at a high speed of 2500 rpm to 4000 rpm, the connecting member with the vibration generator is displaced rearward. Even if the stopper rubber portion on the rear side remains in contact with the stopper member, vibration transmission to the vehicle body in this state is suppressed, and indoor noise can be reduced.

  The small cavity of at least one of the front and rear stopper rubber portions may be a through hole or a non-through hole in a direction intersecting with the front and rear direction. Depending on the diameter and shape of these holes, the stopper rubber portion The rigidity can be set as appropriate.

  As described above, according to the vibration isolator of the present invention, the dynamic spring constant in the front-rear direction can be reduced without affecting the characteristics such as durability and stopper action, and good vibration isolating characteristics can be maintained. Furthermore, it is possible to effectively reduce indoor noise during acceleration and high speed running.

  Next, embodiments of the present invention will be described based on examples shown in the drawings.

  1 is a longitudinal sectional view showing an embodiment of a vibration isolator according to the present invention, FIG. 2 is a longitudinal sectional view taken along the line II-II of the previous figure, and FIGS. 3 and 4 are transverse sectional views of a small cavity portion, FIG. 5 is a graph showing a comparison of indoor noise between the device of the present invention and the vibration isolator of the comparative example.

  In the figure, reference numeral 1 denotes a cylindrical main body metal fitting (first metal fitting) having a substantially open cup shape that is fixed to the vehicle body side as will be described later, and 2 is a boss metal fitting arranged slightly above the axial center ( (Second metal fitting) 3 is vulcanized and bonded between the lower part of the cylindrical main metal fitting 1, for example, the inner peripheral surface of the lower part which forms an inwardly tapered shape as shown in the figure, and the lower outer peripheral surface of the boss metal fitting 2. It is a rubber elastic body as a vibration isolator which is fixedly attached by means. The rubber elastic body 3 basically has a thick, substantially truncated cone shape as shown in the figure. A rubber layer 31 integral with the rubber elastic body 3 is provided on the inner peripheral surface of the cylindrical main body 1 for protection, and the rubber elastic body 3 is also integrated with the outer peripheral surface of the boss metal 2. A rubber layer 32 is provided.

  Reference numeral 4 denotes a connecting member to the vibration generator side fixed to the boss fitting 2, for example, one end of which is fixed to the upper portion of the boss fitting 2 by fastening means using a bolt 41, and from the fixing portion in the left-right direction. The other end portion of the connecting member 4 extending in one side is provided so as to be connected and fixed to the member A on the vibration generating body side such as an engine by a bolt fastening means 42.

  Reference numeral 5 denotes a stopper rubber attached to the outer periphery of the one end portion of the connecting member 4 by the vulcanization adhesive means so as to cover at least the front and rear portions and the upper portion of the connecting member 4. The front and rear portions are integrally formed as front and rear stopper rubber portions 51 and 52, and the upper portion is integrally formed as an upper rubber portion 53.

  The front and rear stopper rubber portions 51 and 52 are not limited to being integrally formed with the stopper rubber 5 as shown in the figure, but can be separately formed on the front and rear sides. Further, depending on the form of the boss fitting 2 or the connection structure between the boss fitting 2 and the member A on the vibration generator side, the stopper rubber portions 51 and 52 can be provided on the upper portion of the boss fitting 2.

  Reference numeral 6 denotes a holding cylinder which has a substantially cup shape with an open bottom, and fixes and holds the cylindrical body fitting 1 by press-fitting as shown in the figure. The holding cylinder 6 has a substantially L-shaped leg portion 61, 61 extending downward from both front and rear side portions and bent outward, and is fastened with a bolt nut or the like to a vehicle body side member B such as a vehicle body frame. It is fixed by means (not shown), and is provided so as to support the tubular body fitting 1 press-fitted and fixed as described above slightly above the member B on the vehicle body side. Of course, other support means can be connected and fixed to the outer periphery of the cylindrical main body 1 for support.

  7 is a stopper member having an arch shape as shown in the figure, which is fixed to the vehicle body side member B together with the leg portions 61 and 61 of the holding cylinder 6 at the front and rear portions of the apparatus. The front and rear of the stopper rubber 5 attached to the outer periphery, that is, the front and rear stopper rubber portions 51 and 52 and the upper rubber portion 53 are provided so as to have a necessary interval set according to the vibration-proof function and the stopper action. It is arranged across.

  That is, the stopper rubber 5 is attached to the connecting member 4 corresponding to the inner portion of the stopper member 7. As a result, the front and rear relatively thick stopper rubber portions 51 and 52 abut against the front and rear support column portions 71 and 72 of the stopper member 7 against the vibration displacement in the front-rear direction of the connecting member 4. In addition, the upper rubber portion 53 comes into contact with the upper portion 73 of the stopper member 7 against the upward displacement of the connecting member 4 so as to perform a stopper action. Reference numeral 8 denotes a stopper rubber portion that restricts the downward displacement of the connecting member 4. 1 and 2 show a state where no load is applied.

  The stopper member 7 does not necessarily have an arch shape as shown in the figure, and can be a stopper member separated front and rear, and is fixed by caulking means at the opening end of the holding cylinder. You can also

  In the vibration isolator of the present invention, at least one of the front and rear stopper rubber portions 51 and 52, for example, the rear stopper rubber portion 52 as shown in the drawing, is provided in the front and rear direction as shown in the sectional view of FIG. A small cavity 10 having a through hole with the same diameter in the crossing direction is provided, thereby softening the contact when the stopper rubber portion 52 abuts against the stopper member 7, and the dynamic spring constant in the front-rear direction is reduced. It can be reduced.

  That is, in the state where the automobile engine is supported, the front and rear stopper rubber portions 51 and 52 abut against the stopper member 7 with respect to the vibration displacement in the front-rear direction on the vibration generating body side when the vehicle is running, and a large displacement beyond that. In this case, since the small cavity 10 is provided in at least one of the front and rear stopper rubber portions 51 and 52, at least one of the stopper rubber portions 51 and / or up to a certain amplitude range. 52 is easily elastically deformed, and the stopper member 7 is softly hit.

  As a result, the dynamic spring constant in the front-rear direction can be reduced, and good vibration isolation characteristics can be exhibited against vibrations having a relatively small amplitude. Particularly, when the small cavities 10 are provided in both the front and rear stopper rubber portions 51 and 52, since the contact is soft in both the front and rear directions, the effect of reducing the dynamic spring constant is further increased. growing. Moreover, at the time of vibration with a large amplitude, the small cavity 10 is crushed and the wall surface of the small cavity 10 is brought into close contact with each other, so that the spring force as a stopper is increased, and a good stopper action is achieved as in the conventional case, impairing durability. There is nothing.

  Further, when the vehicle is accelerated or the engine rotates at a high speed of 2500 rpm to 4000 rpm, the coupling member 4 on the vibration generator side is displaced rearward, and the rear stopper rubber portion 52 remains in contact with the stopper member 7. However, when the small cavity 10 is provided at least in the rear stopper rubber portion 52 as in the illustrated embodiment, the contact of the rear stopper rubber portion 52 against the stopper member 7 is soft. Therefore, vibration transmission to the vehicle body in this state is suppressed, and indoor noise can be reduced as compared with the conventional product.

  The shape (cross-sectional shape), size, arrangement position and number of the small cavities 10, the direction of the holes, and the like can be variously changed according to required rigidity, dynamic spring constant, vibration isolation characteristics, and the like.

  For example, the small cavity 10 may be a non-through hole formed by leaving the non-penetrating part 11 in a part as shown in FIG. 4 in addition to the through hole. In the case of the small cavity 10 by this non-through hole, the position and wall thickness of the non-penetrating portion 11 can be set as appropriate, and the tuning of the rigidity is facilitated by changing the position or wall thickness or changing the hole diameter.

  Further, in both cases of the through hole and the non-through hole of the small cavity 10, it is formed in the middle portion of the thickness of the front and rear stopper rubber portions 51 or 52, and is disposed in the vicinity of the tip portion or in the proximity of the connecting member 4. Furthermore, a plurality of rubber parts 51 and / or 52 on the front and rear sides can be arranged, the cross-sectional shape of the hole can be made substantially triangular or flat, and the direction of the hole is arranged vertically. You can also In any of these cases, the contact with the stopper member can be eased in the same manner as described above, the dynamic spring constant in the front-rear direction can be reduced, and noise transmission during acceleration and high-speed running can be reduced.

  FIG. 5 shows a case where the device of the present invention having a stopper rubber structure having a small cavity of the embodiment shown in FIG. 1 is used as a mount for supporting an engine mounted on an automobile, and a small cavity according to a comparative example shown in FIG. In order to compare the indoor noise with the case of using a rubber vibration isolator with no stopper rubber structure, the result of measuring the sound pressure level at the driver's seat in the room while changing the engine speed is shown. . In the figure, the solid line indicates the anti-vibration device of the comparative example, and the broken line indicates the case of the device of the present invention.

  As is apparent from this measurement result, in the range of high-speed running of the engine speed of about 2500 rpm to about 4000 rpm, the sound pressure level in the case of the device of the present invention is several decibels to 5 decibels compared to the device of the comparative example. The front and rear are also low (shaded area in FIG. 5), and it can be seen that noise can be reduced by the device of the present invention.

  In the illustrated embodiment, the case of a non-liquid-encapsulated vibration isolator using only a rubber elastic body is shown. However, the present invention utilizes the liquid flow effect of the orifice by enclosing the liquid inside the main body. The liquid-sealed vibration isolator can be implemented in the same manner as described above, and the same effect can be exhibited.

It is a longitudinal cross-sectional view which shows one Example of the vibration isolator which concerns on this invention. It is a longitudinal cross-sectional view of the II-II line of the previous figure. It is a cross-sectional view of the small cavity part of the apparatus same as the above. It is a cross-sectional view of a small cavity portion showing another embodiment. It is a graph which shows the comparison of the indoor noise about this invention apparatus and the apparatus of a comparative example. It is a longitudinal cross-sectional view which shows the vibration isolator of a comparative example.

Explanation of symbols

A A member on the vibration generator side B A member on the vehicle body side 1 A cylindrical body metal fitting 2 A boss metal fitting 3 A rubber elastic body 4 A connecting member 5 A rubber for a stopper 6 A holding cylinder 7 A stopper member 10 A small cavity 11 A non-penetrating portion 51, 52 Part 53 Upper rubber part 61, 61 Leg part 71, 72 Front / rear strut part

Claims (4)

A cylindrical first metal fitting fixed to the vehicle body side, a second metal fitting arranged slightly above the axial center of the first metal fitting and connected to the vibration generator side, and an intermediate between both the first metal fitting and the second metal fitting. A front and rear stopper rubber portion attached to a connecting member between the rubber elastic body provided and the vibration generating body fixed to the upper portion of the second metal fitting or the upper portion of the second metal fitting, and front and rear of the stopper rubber portion. In the vibration isolator having a front and rear direction stopper member that is arranged and fixed to the vehicle body side, and that performs a front and rear direction stopper action by the stopper rubber portion and the stopper member,
A vibration isolator having a small cavity provided in at least one of front and rear stopper rubber portions.   The vibration isolator according to claim 1, wherein the small cavity is provided at least in a stopper rubber portion on the rear side.   The vibration isolator according to claim 1 or 2, wherein the small cavity is a through hole in a direction intersecting with the front-rear direction.   The vibration isolator according to claim 1 or 2, wherein the small cavity is a non-through hole in a direction intersecting with the front-rear direction.

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