JP4780991B2 - Anti-vibration support structure for engine mount and power unit using the same - Google Patents

Description

  The present invention relates to an engine mount that supports a vehicle power unit on a vehicle body in an anti-vibration manner, and an anti-vibration support structure on the vehicle body of the power unit using the engine mount.

  In general, in a vehicle, a support mechanism of a power unit by a vehicle body is realized by using a rubber mount called an engine mount. The vibration transmission from the power unit to the vehicle body is reduced by elastically supporting the power unit with respect to the vehicle body with a plurality of rubber mounts.

  As one type of such an engine mount, there is conventionally known one using a main rubber elastic body having a solid rectangular block shape. Such an engine mount is, for example, disclosed in Patent Document 1 (Japanese Utility Model Publication No. 58-20918) and the like. The second mounting bracket is mounted by being fixed to the power unit side and the vehicle body side. At that time, a pair of engine mounts are disposed obliquely downward on both sides across the inertia main shaft of the power unit. In addition, in order to mutually adjust the spring characteristics in the roll direction and the spring characteristics in the vertical and horizontal directions of the vehicle, generally, the vertical axis extending in the opposing direction of the first mounting bracket and the second mounting bracket is vertical. It is tilted by a predetermined amount with respect to the axis. Thereby, the vertical axis | shaft of this pair of engine mounts is made to cross | intersect mutually upwards.

  However, in an engine mount made of such a main rubber elastic body, the vibration isolation performance in a specific frequency region may be lowered. This phenomenon of reduced vibration isolation performance occurs in a specific frequency range, so it is estimated that it is caused by the resonance phenomenon of the main rubber elastic body, brackets, etc., but the generated frequency range is a problem for vehicle vibration isolation. It becomes a big problem when it becomes an easy frequency.

  In order to deal with such a problem, it is conceivable to change the resonance frequency by changing the spring characteristics of the rubber elastic body of the main body, but there is a risk of adversely affecting the originally required vibration isolation support performance of the power unit. Yes, practically difficult to adopt. In addition to the engine mount, it may be possible to install other vibration isolation devices such as vibration dampers in order to reduce vehicle vibrations in the problematic frequency range. This is not practical because it involves problems such as an increase in manufacturing cost, an increase in manufacturing cost, and an increase in mass and required installation space.

Japanese Utility Model Publication No. 58-20918

  Here, the present invention has been made in the background as described above, and the problem to be solved is an engine mount that is composed of a rubber elastic body having a substantially rectangular block shape and is mounted in an inclined state. An object of the present invention is to provide an engine mount having a novel structure capable of avoiding a reduction in vibration-proof performance in a specific frequency range, which is considered to be caused by a resonance phenomenon, with a simple structure. Another object of the present invention is to provide a power unit anti-vibration support structure having a novel structure employing such an engine mount.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. Further, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or an invention that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on thought.

The feature of the present invention relating to the engine mount is that the upper and lower end faces, the left and right end faces, and the front and rear end faces are respectively positioned on a substantially rectangular block-shaped main rubber elastic body that is spaced apart on three orthogonal axes. By attaching the upper mounting bracket and the lower mounting bracket to the end surface and the lower end surface, fixing the upper mounting bracket to the power unit side, and fixing the lower mounting bracket to the vehicle body side, the front and rear extending in the separation direction of the front and rear end surfaces The directional axis is inclined at a predetermined angle around the longitudinal axis so as to extend substantially horizontally in the longitudinal direction of the vehicle, and extends in the separated direction of the left and right end surfaces and the vertical axis extending in the separated direction of the upper and lower end surfaces. in the engine mount mounted in a state of being inclined at a predetermined angle with the horizontal direction axis with respect to the horizontal axis extending in the vertical axis and the vehicle transverse direction, respectively, to a substantially vertical plane both the front and rear end faces In addition, mass projections that are located at substantially central portions of the front end surface and the rear end surface and project outward on the front-rear axis are integrally formed on the main rubber elastic body, and the mass projections and main body rubber The elastic body is composed of one rubber block.

  In the engine mount having such a structure according to the present invention, the vibration-proof characteristic was measured, and compared with the engine mount of the conventional comparative structure in which the mass protrusions are not formed on the front and rear end surfaces, the specific frequency range. It was confirmed that the function of the tuned dynamic damper was effectively demonstrated. It was also confirmed that the frequency range in which the dynamic damper function is exhibited can be changed and set by adjusting the size and the like of the mass protrusions formed on the front and rear end faces.

  Therefore, in the engine mount of the present invention, by forming a mass protrusion of an appropriate size, a low dynamic spring is achieved in the problematic frequency range, and the vibration isolation performance in the frequency range is achieved. It can be improved.

  In particular, according to the present invention, an engine mount having a specific structure formed of a substantially rectangular block-shaped main rubber elastic body and having a specific mounting state inclined in a predetermined direction has a mass relative to both front and rear end faces. By integrally forming the protrusions, (i) the effect that the dynamic damper function by such mass protrusions can be effectively and stably exhibited, and (ii) the original spring characteristics of the mount by forming the mass protrusions Both the effect of avoiding adverse effects on the rubber and (iii) the effect of avoiding the decrease in the durability of the rubber elastic body due to the formation of the mass protrusions are both effectively exhibited.

  That is, in the engine mount using the rectangular block-shaped main rubber elastic body, which is the subject of the present invention, when the shared support load of the power unit is input and further the vibration load is input, An external force is applied in an inclined direction inclined by a predetermined angle with respect to the mount center axis facing the mounting bracket. By this external force action, the main rubber elastic body undergoes compressive deformation in the direction along the mount center axis serving as one elastic main axis and shear deformation in the direction perpendicular to the mount center axis. Due to such deformation, the left and right end surfaces of the main rubber elastic body are curved and deformed relatively large. On the other hand, since both front and rear end faces of the main rubber elastic body are substantially vertical surfaces, the main rubber elastic body is deformed while maintaining a substantially flat surface shape as much as possible.

  In the present invention, the mass protrusions are formed on the front and rear end faces, so that when the main rubber elastic body is elastically deformed due to the input of the vibration load, the longitudinal axis that is the protruding direction of the mass protrusion is the same. As a result, an excitation force in a direction substantially perpendicular to the surface of the main rubber elastic body is effectively exerted, and compression / tensile deformation of the mass protrusion itself due to the curved deformation of the surface of the main rubber elastic body is effectively suppressed. Therefore, as described in (i) above, the dynamic damper function by such mass protrusions can be effectively exerted, and the peak of the dynamic spring constant in a specific frequency range considered to be caused by the resonance phenomenon of the main rubber elastic body is suppressed. It becomes possible.

  In addition, since the mass protrusions are formed on the front and rear end surfaces, the left and right curved deformations of the main rubber elastic body that occur when a shared support load or vibration load is input are not hindered by the mass protrusions. In addition, the elastic deformation of the mass protrusions on both the front and rear surfaces of the main rubber elastic body is mainly shear deformation. Therefore, as described in (ii) above, the adverse effect of the mass protrusion on the original spring characteristics of the main rubber elastic body can be suppressed, and the original vibration-proof performance of the main rubber elastic body can be effectively exhibited. Further, as described in (iii) above, the deformation restraining force on the main rubber elastic body by the mass protrusions can be kept low, and the decrease in durability due to the concentration of stress and strain can be effectively avoided.

  By the way, in an engine mount having a structure according to the present invention, a structure in which the mass protrusion is formed to protrude with a substantially constant circular cross section is suitably employed.

  By making the mass protrusion into a circular block shape with a circular cross section, substantially the same spring characteristics and hence dynamic damper characteristics can be expected in any direction perpendicular to the axis. In addition, compared to the case where rectangular block-shaped mass protrusions are used, the processing of the molding die for integrally forming the main rubber elastic body and the release after the molding become easier, making the manufacture of the engine mount easier. In addition, the manufacturing cost can be reduced. Furthermore, by making the outer peripheral surface circular and connecting the main rubber elastic body circular, stress concentration during elastic deformation can be avoided and durability can be improved.

  Moreover, in this invention, the structure which made the main body rubber elastic body the front-and-rear both-ends surface in which the mass protrusion part was formed was smaller than the left-right both end surfaces is employ | adopted suitably. The left and right end faces and both front and rear end faces of the main rubber elastic body are subjected to external force before mounting in consideration of the reduction of tensile stress when inputting elastic deformation in the mounted state where a shared support load is applied. In a state where it is not, it is desirable that the center portion has a curved surface shape with respect to the upper and lower end edges.

  Furthermore, in the present invention, the total mass Ma of the mass projections formed on the front and rear end faces is Ma / Mt ≧ with respect to the total mass Mt of the main rubber elastic body excluding the mass projections. It is desirable to be 0.09.

  When the lid is covered and the mass of the mass protrusion relative to the total mass of the main rubber elastic body is too small, it may be difficult to effectively obtain the intended dynamic damper effect. On the other hand, if the mass of the mass protrusion relative to the total mass of the main rubber elastic body is too large, the deformation restraining force of the main rubber elastic body by the mass protrusion increases, and the original spring characteristics of the main rubber elastic body change, There is a possibility that a problem arises in that the vibration force caused by the displacement of the mass protrusion has an adverse effect on the rubber elastic body of the main body and the vibration-proof performance is lowered.

  Further, the present invention is such that a pair of engine mounts structured as described above according to the present invention is disposed between the power unit and the vehicle body at an obliquely lower side on both sides of the inertia main shaft of the power unit. An anti-vibration support structure for a power unit in which the vertical axis of the pair of engine mounts is inclined in a direction intersecting with each other upward, and the longitudinal axis of the engine mounts extends substantially horizontally in the longitudinal direction of the vehicle. To do.

  As is clear from the above description, in the engine mount having the structure according to the present invention, the mass protrusions are integrally formed on the front and rear end surfaces of the main rubber elastic body, so that the dynamic damper by the mass protrusions is formed. The function can be effectively and stably exhibited, and the adverse effect on the spring characteristic of the mount and the deterioration of the durability of the main rubber elastic body due to the formation of the mass protrusion can be advantageously avoided.

  In addition, in the anti-vibration support structure of the power unit configured according to the present invention, the use of the engine mount according to the present invention reduces the anti-vibration performance in a specific frequency range that is considered to be caused by a resonance phenomenon. This can be avoided with a simple structure. As a result, the desired vibration isolation effect can be stably obtained, and the manufacturing cost can be advantageously reduced.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described. 1 to 4 show an engine mount 10 as an embodiment of the present invention. The engine mount 10 has a structure in which an upper fitting 12 as an upper fitting and a lower fitting 14 as a lower fitting are arranged at a predetermined distance and are connected to each other by a main rubber elastic body 16. Yes. In the following description, unless otherwise specified, the vertical direction refers to the vertical direction in FIG.

  More specifically, the upper metal fitting 12 has a substantially rectangular flat plate shape, and is formed using a rigid member such as a metal material. In addition, a fixing bolt 18 is integrally formed and protruded at a substantially central portion of the upper metal member 12, and a protruding portion 20 having a substantially cylindrical shape with a small diameter protrudes from a position deviated from the central portion. ing.

  Further, upper stopper portions 22 are integrally formed at both ends in the width direction (left and right in FIG. 2) of the upper metal fitting 12. The upper stopper portion 22 has a substantially rectangular flat plate shape, and extends downward from the end of the upper metal fitting 12 (downward and rightward in FIG. 1).

  Further, the lower metal fitting 14 is disposed on the upper metal fitting 12 at a predetermined distance. The lower metal fitting 14 has a long, substantially rectangular flat plate shape, and is formed using a rigid member such as a metal material.

  Further, fixing holes 24 as bolt fixing positions are respectively provided on both sides in the longitudinal direction (upper and lower in FIG. 2) of the lower metal fitting 14.

  Further, lower stopper portions 26 are integrally formed at both ends in the width direction (left and right in FIG. 2) in the longitudinal center portion of the lower metal fitting 14. The lower stopper portion 26 has a substantially rectangular flat plate shape, and extends upward from the end portion of the lower metal fitting 14 (upwardly diagonally left in FIG. 1).

  In particular, in this embodiment, the width dimension of the lower metal fitting 14 is made larger than the width dimension of the upper metal fitting 12. Further, the height dimension of the lower stopper portion 26 is made larger than the height dimension of the upper stopper portion 22. The upper metal fitting 12 is opposed to the central portion in the longitudinal direction of the lower metal fitting 14 at a predetermined distance. Thus, the upper end portion of the lower stopper portion 26 overlaps the lower end portion of the upper stopper portion 22, and the pair of upper stopper portions 22, 22 enters between the pair of lower stopper portions 26, 26. Thus, the upper stopper portions 22 and the lower stopper portions 26 on both sides in the width direction (left and right in FIG. 2) are opposed to each other with a predetermined distance in the width direction.

  Further, a main rubber elastic body 16 is disposed between the opposing surfaces of the upper metal fitting 12 and the lower metal fitting 14. The main rubber elastic body 16 has a substantially rectangular block shape, and is formed using a rubber material such as NR, BR, or SBR. That is, a vertical axis 32 extending in the separation direction (left and right in FIG. 3) of the upper end surface 28 and the lower end surface 30 in the main rubber elastic body 16 and the separation direction of the left end surface 34 and the right end surface 36 (right diagonal in FIG. 1). A horizontal axis 38 extending upward or diagonally to the left) and a longitudinal axis 44 extending in the separation direction (up and down in FIG. 3) of the front end surface 40 and the rear end surface 42 are used as the center of gravity or the center of gravity of the main rubber elastic body 16. At close positions, they are orthogonal to each other.

  As a result, when the main rubber elastic body 16 is rotated about the front-rear axis 44 with the front-rear axis 44 being substantially horizontal, the vertical axis 32 and the left-right axis 38 are respectively vertical axes extending in the vertical direction in FIG. In addition, the upper and lower end faces 28 and 30 and the left and right end faces 34 and 36 of the main rubber elastic body 16 are also inclined at a predetermined angle. It is supposed to be. On the other hand, the front and rear end surfaces 40 and 42 are arranged so that the front and rear direction shaft 44 becomes the front and rear end surfaces 40 and 42 even when the main rubber elastic body 16 is rotated about the front and rear direction axis 44 with the front and rear direction shaft 44 being substantially horizontal. Since they are orthogonal to each other, they are configured to be substantially parallel to the vertical axis and substantially orthogonal to the horizontal axis. That is, the front and rear end faces 40 and 42 are largely inclined at a predetermined angle with respect to the vertical axis and the horizontal axis even when the main rubber elastic body 16 is rotated about the front and rear direction axis 44 with the front and rear direction axis 44 being substantially horizontal. It is considered as a vertical plane that is never used.

  The left and right end surfaces 34 and 36 and the front and rear end surfaces 40 and 42 of the main rubber elastic body 16 are substantially flat, but each surface is slightly curved concavely outward. Yes. Thereby, the stress of each surface 34, 36, 40, 42 accompanying the compression deformation, tensile deformation, shear deformation, etc. in the main rubber elastic body 16 can be suppressed.

  Further, the upper end surface 28 of the main rubber elastic body 16 is vulcanized and bonded to the surface of the upper metal member 12 facing the lower metal member 14, and the lower end surface 30 of the main rubber elastic body 16 is connected to the upper metal member of the lower metal member 14. The surface facing 12 is vulcanized and bonded. In short, the main rubber elastic body 16 is formed as an integrally vulcanized molded product including the upper metal fitting 12 and the lower metal fitting 14. The above-described vertical axis 32 extends in a direction in which the upper metal fitting 12 and the lower metal fitting 14 face each other, and the left-right direction shaft 38 and the front-rear direction shaft 44 are orthogonal to the opposing direction of the upper metal fitting 12 and the lower metal fitting 14. It extends to.

  A buffer rubber 46 is formed on the surface of each upper stopper portion 22 that faces the lower stopper portion 26. The buffer rubber 46 is integrally formed with the main rubber elastic body 16 when the main rubber elastic body 16 is vulcanized, and from the central portion of each upper stopper portion 22 in the width direction (up and down in FIG. 2) to the lower stopper portion. 26 is a section that gradually tapers as it goes to 26, and extends in a protruding direction of the upper stopper portion 22 (downward and rightward in FIG. 1) by a predetermined length. Accordingly, the upper stopper portions 22 on both sides in the width direction of the upper metal fitting 12 are opposed to the lower stopper portions 26 on both sides in the width direction of the lower metal fitting 14 with a predetermined distance therebetween via the buffer rubber 46. It has been. A stopper mechanism 48 is configured including each of the pair of upper stopper portions 22 and 22, the lower stopper portions 26 and 26, and the buffer rubber 46. 46.

  Here, mass projections 50 are integrally formed on the front end face 40 and the rear end face 42 of the main rubber elastic body 16. The pair of mass projecting portions 50, 50 are located substantially at the center of the front end surface 40 and the rear end surface 42, and project outward on the front-rear direction shaft 44. The shape, size, mass, spring constant, and the like of the mass protrusion 50 are appropriately set and changed according to required durability performance, spring characteristics, dynamic damper effect described later, and the like, and are particularly limited. Not a thing.

  In particular, in the present embodiment, the mass protrusion 50 has a substantially cylindrical shape, and extends along the front-rear direction axis 44 with a substantially constant circular cross section. Further, a projection height l projecting from the front end surface 40 or the rear end surface 42 of each mass protrusion 50 onto the front-rear direction shaft 44 and a separation distance L between the front end surface 40 and the rear end surface 42 on the front-rear direction shaft 44. Is 1/5 ≦ l / L ≦ 1/2.

  Further, the outer peripheral edge portion of the base end portion of the mass projecting portion 50 having a circular shape does not have a bending point with each end surface 40, 42 of the main rubber elastic body 16, and has a smooth curve on each end surface 40, 42. It touches. As a result, it is possible to reduce or avoid the occurrence of large stresses and distortions locally at the connecting portion between the main rubber elastic body 16 and the mass protrusion 50.

  Furthermore, the total mass Ma of the mass projections 50, 50 is set to Ma / Mt ≧ 0.09 with respect to the total mass Mt of the main rubber elastic body 16 excluding the mass projections 50, 50. .

  As shown in FIG. 5, the pair of engine mounts 10 structured as described above is mounted between the power unit 52 and the vehicle body 54 as the vehicle body. The power unit 52 including an engine, a transmission, and the like has a pair of mounting brackets extending in a substantially horizontal direction vertically below the inertia main shaft on both sides of the inertia main shaft extending in the direction of the torque roll axis through the center of gravity. 56, 56 are fixed. An end portion of the mounting bracket 56 is inclined toward an obliquely downward inner side of the power unit 52. Further, the vehicle body 54 is formed with a mounting seat surface 58 extending substantially parallel to the direction in which the end portion extends at a position corresponding to the end portion of each mounting bracket 56. The upper bracket 12 of the engine mount 10 is overlaid on the end of the mounting bracket 56, and the projection 20 of the upper bracket 12 is locked in the positioning hole formed at a predetermined position of the end. The fixing bolt 18 of the upper metal fitting 12 is inserted and fixed by screwing with a fixing nut 60. Further, the lower bracket 14 of the engine mount 10 is overlaid on the mounting seat surface 58, and the fixing bolt 62 is inserted into the fixing hole 24 of the lower bracket 14 and is fixed by screwing with the fixing nut 64. Thus, the pair of engine mounts 10 and 10 are respectively disposed on both sides of the power unit 52 with the torque roll shaft interposed therebetween, and the elastic main shaft of the main rubber elastic body 16 extending in the opposing direction of the upper metal fitting 12 and the lower metal fitting 14 is provided. The power unit 52 is mounted between the power unit 52 and the vehicle body 54 in a state where the power unit 52 is inclined obliquely upward.

  In such a mounted state, the longitudinal axis 44 of each engine mount 10 is substantially horizontal and extends parallel to the longitudinal direction of the vehicle. Further, the mount 10 is inclined at a predetermined angle around the front-rear axis 44, and the vertical axis 32 and the left-right axis 38 of the mount 10 are respectively a vertical axis and a vehicle extending in the vehicle vertical direction (up and down in FIG. 5). It is inclined at a predetermined angle with respect to a horizontal axis extending in the left-right direction (left and right in FIG. 5). As a result, the upper and lower end surfaces 28 and 30 and the left and right end surfaces 34 and 36 of the main rubber elastic body 16 are predetermined with respect to the vertical axis and the horizontal axis, respectively, based on the inclination angles of the vertical axis 32 and the horizontal axis 38. It is tilted at an angle. On the other hand, the front and rear end faces 40, 42 of the main rubber elastic body 16 are tilted even when the mount 10 is rotated about the front-rear axis 44 as the mount 10 is tilted about the front-rear axis 44. Similar to the state when there is no vehicle, it is a substantially vertical surface extending substantially parallel to the vehicle vertical direction (vertical direction).

Under such a mounted state, when a shared support load of the power unit 52 is exerted on each engine mount 10, the main rubber elastic body 16 moves in the direction along the mount center axis serving as one elastic main axis, that is, the upper metal fitting. 12 and the lower metal fitting 14 are compressed and deformed in the opposing direction, and shear-deformed in a direction orthogonal to the mount center axis. By the elastic deformation of the main rubber elastic body 16, as shown in FIG. 1, (in FIG. 1, upper right) widthwise whereas the upper member 12 lower member 14 forms a mount 10 which is biased in the FIG. 5 As shown in FIG. 5, the upper metal fitting 12 is positioned at the approximate center in the width direction of the lower metal fitting 14, and the separation distance between each pair of the upper stopper portion 22 and the lower stopper portion 26 in the stopper mechanism 48 is substantially equal. It becomes the form made into an interval. Therefore, when a load having a predetermined magnitude such as a lateral direction (vehicle left-right direction) is input between the power unit 52 and the vehicle body 54, the upper stopper portion 22 and the lower stopper portion 26 in the stopper mechanism 48 are cushioned. By abutting through 46, the relative displacement between the power unit 52 and the vehicle body 54 is limited in a buffering manner.

  In the engine mount 10 having the above-described structure, when the shared support weight of the power unit 52 is input and further a vibration load is input thereon, the upper mount 12 and the lower mount 14 are in relation to the mount center axis of the mount. Thus, an external force is applied in a direction inclined by a predetermined angle. By this external force action, the main rubber elastic body 16 connecting the upper metal fitting 12 and the lower metal fitting 14 is subjected to compressive deformation in the direction of the mount center axis serving as one elastic main axis and shear deformation in a direction perpendicular to the mount center axis. Based on this deformation action, an effect of reducing vibration transmission from the power unit 52 to the vehicle body 54 can be exhibited.

  In this case, the mass dampers 50 and 50 are formed on the front and rear end faces 40 and 42 of the main rubber elastic body 16, whereby the dynamic damper function can be effectively exhibited. Therefore, for example, the peak of the dynamic spring constant in the frequency range around 500 Hz, which is considered to be caused by the resonance phenomenon of the main rubber elastic body 16, which is a problem in automobiles or the like, can be effectively reduced.

  Moreover, the front and rear end faces 40 and 42 of the main rubber elastic body 16 where the mass protrusions 50 are formed are substantially vertical surfaces, so that the main rubber elastic body 16 is compressed and deformed when a vibration load is input. Even under shear deformation, the substantially flat surface shape is advantageously maintained as compared with the left and right end surfaces 34 and 36 of the main rubber elastic body 16. Accordingly, since excessive compression / tensile deformation is prevented from occurring in the mass projection 50, the concentration of stress and strain in the mass projection 50 and the main rubber elastic body 16 connected to the mass projection 50 is suppressed. Thus, the durability performance can be advantageously improved. In addition, since the restraining force against the elastic deformation of the main rubber elastic body 16 is reduced, the vibration reducing effect based on the desired spring characteristics can be stably obtained.

  The resonance frequency tuning related to the dynamic damper function can be performed by adjusting the shear dynamic spring constant and mass of the mass protrusion 50 while taking into account the dynamic spring constant and mass of the main rubber elastic body 16, for example. Is possible. Therefore, the vibration-proofing effect based on the target resonance action can be obtained easily and stably without a large design change as a whole.

  The description of the technical operation related to the engine mount 10 described above is inferred at the present time, but has been confirmed by many experiments and examinations by the present inventor including the example data described below. is there.

  Specifically, a known dynamic characteristic test was performed on the engine mount 10 having the structure according to the present embodiment, and the vibration isolation characteristic regarding the absolute spring constant in a predetermined frequency range was measured. The results are shown in FIG. 6 as an example. Further, an engine mount in which the mass protrusions 50 and 50 are not formed on the front and rear end faces 40 and 42 of the main rubber elastic body 16 and the other structure is the same as the engine mount 10 of the embodiment is implemented. In the same manner as in the example, the vibration isolation characteristics regarding the absolute spring constant in a predetermined frequency range were measured. The results are also shown in FIG. 6 as a comparative example.

  From the results shown in FIG. 6 as well, in the engine mount of the comparative example, high dynamic springs are recognized in the frequency range around 500 Hz, which is a problem in automobiles. Is expected to decrease.

  On the other hand, in the engine mount 10 of the embodiment, the peak of the dynamic spring constant is shifted to two of about 425 Hz and about 660 Hz which do not cause a big problem in the vibration isolation performance of the automobile, and the frequency range around 500 Hz is low. It can be seen that the springing is effectively realized. Therefore, it is considered that excellent vibration isolation performance is exhibited based on the dynamic damper effect by the mass protrusion 50.

  As mentioned above, although one embodiment of the present invention has been described in detail, this is merely an example, and the present invention is not limited to any specific description by this embodiment, and is based on the knowledge of those skilled in the art. The present invention can be implemented with various changes, modifications, improvements, etc., and all such embodiments are within the scope of the present invention without departing from the spirit of the present invention. Needless to say, there is.

  For example, the shape, size, mass, and the like of the mass protrusion are not limited to those illustrated. It goes without saying that the configuration is changed by tuning the target resonance frequency.

  In the above embodiment, a pair of engine mounts arranged on both sides of the power unit with the torque roll shaft of the power unit are shown with respect to the automobile. Of course, in addition to this, one or a plurality of mounting devices are provided. It can be arranged at an appropriate location.

It is a longitudinal cross-sectional explanatory drawing which shows the arrangement | positioning state at the time of mounting | wearing the motor vehicle with the engine mount as one Embodiment of this invention. It is an II-II arrow line view in FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is IV-IV sectional drawing in FIG. It is explanatory model figure which shows the state which mounted | wore the motor vehicle with the pair of engine mounts in FIG. FIG. 2 is a graph showing the results of measuring the anti-vibration characteristics of the engine mount in FIG. 1 as an example, and the results of measuring the anti-vibration characteristics of an engine mount having a conventional structure in the same manner as in the example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine mount 12 Upper metal fitting 14 Lower metal fitting 16 Main body rubber elastic body 28 Upper end surface 30 Lower end surface 32 Vertical direction shaft 34 Left end surface 36 Right end surface 38 Left and right direction shaft 40 Front end surface 42 Rear end surface 44 Front and rear direction shaft 50 Mass protrusion 52 Power unit 54 Vehicle Body

Claims (4)

The upper and lower mounting brackets on the upper and lower end surfaces of the elastic body in the shape of a rectangular block with the upper and lower end surfaces, the left and right end surfaces, and the front and rear end surfaces spaced apart on three orthogonal axes. By fixing the upper mounting bracket to the power unit side and fixing the lower mounting bracket to the vehicle body side, the longitudinal axis extending in the separation direction of the front and rear end surfaces extends substantially horizontally in the vehicle longitudinal direction. The vertical axis extending in the separation direction of the upper and lower end faces and the left and right axis extending in the separation direction of the left and right end faces in the vertical axis and the vehicle left-right direction respectively. In the engine mount mounted in a state inclined at a predetermined angle with respect to the extending horizontal axis,
Both the front and rear end surfaces are substantially vertical surfaces, and mass projections that are located at respective substantially central portions of the front end surface and the rear end surface and project outward on the front-rear axis are respectively provided on the main rubber elastic body. An engine mount characterized in that the mass projection and the main rubber elastic body are formed of a single rubber block.
  The engine mount according to claim 1, wherein the mass protrusion is formed to protrude with a substantially constant circular cross section.   The total mass Ma of the mass projections formed on the front and rear end faces is Ma / Mt ≧ 0.09 with respect to the total mass Mt of the main rubber elastic body excluding the mass projections. The engine mount according to claim 1 or 2.   A pair of engine mounts according to any one of claims 1 to 3, wherein the pair of engine mounts are disposed between the power unit and the vehicle body diagonally below both sides of the inertia main shaft of the power unit. An anti-vibration support structure for a power unit, characterized in that the vertical axis of the mount is inclined in a direction intersecting with each other upward, and the longitudinal axis extends substantially horizontally in the longitudinal direction of the vehicle.

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