Liquid sealing type body mount

Abstract

An object of the present invention is to provide a liquid sealing type body mount in which when the vibrating coefficient at 15 Hz frequency is set to about 4 N·s/mm, a moving spring constant of about 100 Hz can be reduced to about 1000 N/mm, so that the sufficient vibration-proof characteristic can be obtained. This liquid sealing type body mount comprises an inner cylinder fixed to one of a body and a frame on the support side, an outer cylinder fixed to the other of them, a rubber elastomer that is provided between the inner and outer cylinders, two liquid chambers, which are formed at portions opposed to each other with the inner cylinder between, and an orifice passage for communicating both the liquid chambers with each other, in which the load of the body is input in the axial direction. Further, end walls in the axial direction in both the liquid chambers are formed of a rubber film which is a part of the rubber elastomer, and this rubber film is formed aslant and outward in the axial direction from the inner cylinder side toward the outer cylinder.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present invention relates to a liquid sealing type body mount provided between a body of a vehicle and a frame on a support side such as a suspension or the like in order to support the body in a vibration-proof manner.

[0003] 2. Background Art

[0004] Heretofore, a body mount used in a rear suspension of a vehicle such as an automobile has been known, in which there are provided an inner cylinder coupled to one of a body of the vehicle and a suspension-side frame for supporting this body, and an outer cylinder coupled to the other of them, these inner and outer cylinders are joined to each other by a rubber elastomer provided between them, two liquid chambers, which are formed at portions opposed to each other with the aforesaid inner cylinder between, are provided between the inner and outer cylinders, and these liquid chambers are communicated with each other by an orifice passage to obtain a vibration damping effect by liquid fluid effect between the two liquid chambers (for example, Japanese Patent Laid-Open Nos. Hei 2-38730 and Sho 62-188832).

[0005] However, in this conventional kind of body mount, it is general that a rubber portion forming an end wall in the axial direction of the aforesaid liquid chamber forms a right angle to an axial center.

[0006] In case that the thus structured mount is used with the aforesaid liquid chambers positioned in the front and back directions of the vehicle, the stable vibration-proof characteristic is obtained in some degree in the upper and lower directions where the load of the body is applied, due to an effect of the decrease of moving spring constant. However, in the front and back directions where the large vibration is applied at the accelerating time such as the starting time or at the braking time, the vibration damping effect becomes small due to the rigidity of the rubber portion of the end wall of the aforesaid liquid chamber. For example, in case that attenuation coefficient with frequency of 15 Hz is set to about 4 N·s/mm, the moving spring constant at about 100 Hz becomes 2000 N/mm and more, so that the sufficient vibration-proof function does not act. Therefore, improvement is further desired.

[0007] The present invention has been made in view of the forgoing. Its object is to provide a liquid sealing type body mount in which regarding the vibration mainly in the front and back direction, in case that, for example, attenuation coefficient with frequency of 15 Hz is set to about 4 N·s/mm, the moving spring constant at about 100 Hz can be reduced to as law as about 1000 N/mm, so that the sufficient vibration-proof characteristic can be obtained.

SUMMARY OF THE INVENTION

[0008] The invention relates to a liquid sealing type body mount provided between a body of a vehicle and a frame on a support side in order to support the body in a vibration-proof manner. The body mount comprises an inner cylinder fixed to one of the aforesaid body and a frame, an outer cylinder fixed to the other of them, a rubber elastomer that is provided between these inner and outer cylinders and couples them to each other, two liquid chambers, which are formed at portions of this rubber elastomer opposed to each other with the aforesaid inner cylinder between and formed between the inner and outer cylinders, and an orifice passage for communicating these liquid chambers with each other. Further, in the body mount in which the load input of the body is performed in the axial direction, end walls in the axial direction in the aforesaid liquid chambers are formed of a rubber film which is a part of the aforesaid rubber elastomer, and the rubber film is formed aslant from the inner cylinder side toward the outer cylinder, that is, outward in the axial direction.

[0009] According to this body mount, when the vibrating power orthogonal to the axial center acts in the opposite direction of the two liquid chambers, since the rubber films forming the end walls in the axial direction of the liquid chambers are formed aslant, the vibration can be damped effectively by the action of this rubber film. For example, in the frequency of 15 Hz, in case that the vibration coefficient is about 4 N·s/mm, the moving spring constant can be reduced to as law as about 1000 N/mm. Therefore, by using this body mount with the aforesaid liquid chambers positioned in the front and back directions of the vehicle, a good vibration-proof characteristic in relation to the vibration in the front and back directions and obliquely in the front and back directions can be obtained.

[0010] In the aforesaid body mount, it is particularly preferable that an angle of inclination of the end wall composed of the aforesaid rubber film in relation to the axial center is 15° to 70°.

[0011] Namely, in case that the angle of inclination is over or below the aforesaid range, the rigidity balance in the direction perpendicular to the axis and in the axial direction is lost respectively, and a bad influence is given to the vibration transmission in each direction. Therefore, it is preferable to set the angle of inclination in the aforesaid range, more preferably in a range of 30° to 60°.

[0012] In the aforesaid liquid sealing type body mount, the end walls composed of the rubber films may extend from the inner cylinder side in the radial direction nearly in the wavy shape, and the closer to the outer cylinder the end walls are, the more they may be expanded outward in the axial direction. In this case, similarly to the foregoing, the moving spring constant can be reduced, and further the free length of the rubber film extends thereby to improve durability.

[0013] Further, it is preferable that the thickness of the end wall composed of the aforesaid rubber film is 2 to 6 mm. Namely, in case that the thickness of the end wall of the aforesaid rubber film is thin, the pressure transmission efficiency of liquid decreases, so that the effect of liquid seal is difficult to produce. Further, in case that the rubber film is too thick, the rigidity of the rubber portion increases and the vibration transmission to the liquid pressure decreases, so that the effect of liquid seal is difficult to produce.

[0014] Further, it is preferable that stoppers extruding from the inner cylinder in the radial direction are provided in both the liquid chambers, and by this stopper, larger displacement than the predetermined displacement can be prevented.

[0015] Particularly, it is preferable that the aforesaid stopper is formed by embedding a metal portion fixed to the inner cylinder in a rubber portion formed integrally with the rubber elastomer, since the shock can be softened when the stopper operates.

[0016] It is particularly preferable that an opening angle in the circumferential direction of the aforesaid liquid chamber is not less than 60° and not more than 140° since the area of the axial end wall of the rubber film can be made large and durability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a longitudinal sectional view taken along a line of X-Y in FIG. 2, showing a first embodiment of a body mount of the present invention.

[0018] FIG. 2 is a sectional view taken along a line of X1-X1 in FIG. 1.

[0019] FIG. 3 is a partially cutaway side view of the same in a state where an outer cylinder is separated from an inner cylinder.

[0020] FIG. 4 is a longitudinal sectional side view except the outer cylinder.

[0021] FIG. 5 is a sectional view taken along a line of X2-X2 in FIG. 4.

[0022] FIG. 6 is a sectional view taken along a line of X3-X3 in FIG. 5.

[0023] FIG. 7 is a bottom view of the same except the outer cylinder.

[0024] FIG. 8 is a longitudinal sectional view except an outer cylinder, showing a second embodiment of the invention.

[0025] FIG. 9 is a transverse sectional view of the same including the outer cylinder.

[0026] FIG. 10 is a longitudinal sectional view showing the attaching state of the body mount of FIG. 8

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Next, modes for carrying out the invention will be described with reference to embodiments shown in drawings.

[0028] In figures, reference numeral 1 designates an inner cylinder coupled and fixed to a body of a vehicle through an attaching member 100 such as a body holder, which is formed in the shape of a comparatively thick cylinder and fixed to the attaching member 100 by a tightening member 101 such as a bolt. Reference numeral 2 designates an outer cylinder, which is attached and fixed through a rubber layer 104 to an annular attaching member 103 of a frame 102 on a support side such as a suspension for supporting the body by a forcing means, and which is nearly concentric with respect to the inner cylinder 1. These inner and outer cylinders 1 and 2 are usually made of metal such as aluminum material, steel or the like.

[0029] Reference numeral 3 designates a rubber elastomer provided between the inner cylinder 1 and the outer cylinder 2. Two liquid chambers 4a, 4b that are formed between the inner and outer cylinders 1 and 2 and opened toward the periphery are provided at portions of this rubber elastomer 3, opposed to each other (symmetrical positions) with the inner cylinder 1 between. These liquid chambers 4a, 4b are communicated with each other by an orifice passage 6 which will be described later.

[0030] In the aforesaid rubber elastomer 3, its inner surroundings are adhered by vulcanization to the inner cylinder 1, and to its outer surroundings, a middle cylinder 5 fitted inside the outer cylinder 2 is adhered by vulcanization. This middle cylinder 5 has a flange portion 51 faced outward on the lower end side, and window-like openings 5a, 5b at its portions corresponding to both the liquid chambers 4a, 4b. And, on the peripheral surface of this middle cylinder 5, a rubber layer 31 for seal that is formed integrally with the rubber elastomer 3 is provided, a convex rib 32 is provided at a part of the rubber layer 31, and this middle cylinder 5 is air-tightly fitted inside the outer cylinder 2 through the rubber layer 31 and the convex rib 32, whereby the rubber elastomer 3 is provided between the inner cylinder 1 and the outer cylinder 2 and the liquid chambers 4a, 4b in which liquid is sealed are formed. The aforesaid outer cylinder 2 is caulked in a state where a flange 21 at the lower end portion thereof is fitted to the flange portion 51 of the middle cylinder 5.

[0031] Further, at the peripheral portion of the middle cylinder 5, a recess groove 6a extending in the circumferential direction between the openings 5a and 5b is provided. By fitting the outer cylinder 2 to the outside of the middle cylinder 5, the recess groove 6a functions as an orifice passage 6 for communicating the liquid chambers 4a and 4b to each other.

[0032] Each opening angle θ in the circumferential direction of the two liquid chambers 4a and 4b, that is, an opening angle θ of the liquid chamber defined by the opening 5a and 5b of the middle cylinder can be set voluntarily according to the characteristics. However, it is usually set in a range not less than 60° and not more than 140°. In this connection, the aforesaid opening angle θ is about 70° in this embodiment. From a viewpoint of durability and so on, it is preferably 80° or more.

[0033] Reference numeral 7 designates a stopper that protrudes in both the liquid chambers 4a and 4b from the inner cylinder 1 in the radial direction. When a large displacement in the protruding direction of the stopper 7 is produced, the stopper comes into contact with the chamber wall surface opposed to the stopper, that is, the inner surface of the outer cylinder 2, whereby the larger displacement is controlled. The stopper 7 is so formed projectingly that its leading end surface has a small gap in relation to the chamber wall surface on the liquid chamber peripheral side or slightly comes into contact with the chamber wall surface. The gap between its leading end surface and the chamber wall surface is set to, for example, about 1 mm or less. For example, the aforesaid leading end surface may slightly come into contact with the chamber wall surface. Further, there is also an effect that the gap between its leading end surface and the chamber wall surface gives the fluid resistance of liquid at the time of the vertical (axial) vibration.

[0034] The stopper 7 is usually formed, as shown in the figures, by embedding a metal portion 71 fixed to the inner cylinder 1 in a rubber portion 72 formed integrally with the rubber elastomer 3 so that the contact of the stopper 7 with the aforesaid chamber wall surface is elastically performed. To set the circumferential width of this stopper 7 including the metal portion 71 large can prevent the excessive distortion and can improve durability.

[0035] In the body mount having the aforesaid constitution, both the end walls 40a, 41a; 40b, 41b in the axial direction of both the liquid chambers 4a, 4b are formed of a rubber film formed integrally with the rubber elastomer 3 and having the predetermined thickness, and the rubber film slopes from the inner cylinder 1 to the outer cylinder 2 outward in the axial direction, extends nearly in line, and is coupled to the outer cylinder 2. Namely, as a whole, the liquid chambers 4a, 4b have a longitudinal section nearly in the shape of Y on the periphery side.

[0036] An angle of inclination of each of the end walls 40a, 41a; 40b, 41b composed of the rubber film in relation to the axial center is set in a range of 15° to 70°, preferably in a range of 30° to 60°. Further, the thickness of each of the end walls 40a, 41a; 40b, 41b composed of the rubber film is set in a range of 2 to 6 mm.

[0037] Further, both the end surfaces in the axial direction of the rubber elastomer 3 between both the liquid chambers 4a and 4b are not limited to the linearly inclined surfaces similar to the outer surfaces of the end wall 40a, 41a; 40b, 41b composed of the rubber film or the wavy inclined surface. Particularly, the axial end surfaces of the rubber elastomer 3 on the downward side may be such concave surfaces that they form the inclined surfaces reverse to the inclined surfaces of the end walls 41a, 41b, as shown in FIG. 5. Reference numeral 33a designates its concave portion.

[0038] Further, on the lower surface of the flange portion 51 of the middle cylinder 5, a stopper rubber 81 formed integrally with the rubber elastomer 3 is provided by a vulcanizing adhesion means in order to control the larger displacement than the predetermined displacement by bringing a fitting plate 82 fixed to the lower end of the inner cylinder 1 into contact with the stopper rubber 81 elastically when the inner cylinder 1 greatly moves upward with the vibration of the body. Further, in the attaching state of FIG. 1, to the inner cylinder 1 upward of the attaching member 103 of the frame 102, a stopper member 85 in which a stopper rubber 84 is provided for a ring metal parts 83 is fitted, and the lower surface of the attaching member 100 comes into contact with the stopper member 85 elastically at the time of the downward displacement of the body thereby to control the larger displacement than the predetermined displacement.

[0039] The thus structured liquid sealing type body mount of the invention is used in a rear suspension or the like of a vehicle such as an automobile as shown in FIG. 1 so that the inner cylinder 1 is fixed to the attaching member 100 on the body side by the tightening member 101 such as a bolt and the outer cylinder 2 is forced in the attaching hole 103 of the attaching member 102 on the frame side of the suspension thereby to be fixed. Particularly, in this case, the body mount is attached so that each of the liquid chambers 4a and 4b are positioned in the front and back directions of the vehicle.

[0040] In the aforesaid use of this body mount, the moving spring constant in the vertical direction where the load of the body is applied can be lowered. Further, also in the front and back directions orthogonal to the axis center and obliquely in the front and back directions, where the large vibration is applied at the accelerating time such as the vehicle starting time or at the braking time, since the rubber films forming the end walls 40a, 41a; 40b, 41b in the axial direction of the liquid chambers 4a, 4b are formed obliquely, the rigidity in relation to the vibration in the aforesaid directions and the elasticity becomes smaller than in case of the rubber film orthogonal to the axial center, so that the moving spring constant is reduced by the effect of this rubber film, which heightens the vibration damping effect in cooperation with the liquid fluid effect between both the liquid chambers 4a and 4b.

[0041] For example, in a frequency of 15 Hz, in case of a damping coefficient of about 4 N·s/mm, the moving spring constant of about 100 Hz can be reduced to as law as about 1000 N/mm. Hereby, the good vibration-proof characteristic in relation to the vibration in the front and back directions and obliquely in the front and back directions can be obtained.

[0042] FIGS. 8 to 10 show a second embodiment of the invention, in which since its basic constitution is common to that of the above embodiment, the same components are denoted by the same reference characters and the detailed description is omitted.

[0043] In this embodiment, both end walls 40a, 41a; 40b, 41b composed of a rubber elastomer 3 in the axial direction of two liquid chambers 4a and 4b opposed to each other with an inner cylinder 1 between extend from the inner cylinder 1 side in the radial direction so as form the nearly wavy shape comprising continuous curved surfaces having reverse curvatures alternately. The closer to the outer cylinder 2 side the end wall is, the more it is expanded outward in the axial direction. In this case, it is preferable that an angle of inclination of a line connecting joints at which each of the end walls 40a, 41a; 40b, 41b meets the inner cylinder 1 or the outer cylinder 2 in relation to the axial center is set in a range similar to that in the above first embodiment. Also, it is preferable to set the thickness of the end wall similarly.

[0044] In case that the end walls 40a, 41a; 40b, 41b are formed nearly in the wavy shape like in this embodiment, since the free length of a rubber film forming the end wall is extent, which is different from the case that the end walls extend obliquely in line or in a slightly curved manner as shown in FIGS. 1 to 7, stress at the time of distortion can be reduced and durability improves.

[0045] Further, in case of the embodiment shown in FIGS. 8 to 10, opening angles θ in the circumferential direction of both the liquid chambers 4a, 4b are set large to about 90° to 100°. By thus setting the opening angle θ large, preferably to 80° and more, the areas of the rubber films of the end walls 40a, 41a; 40b, 41b in the axial direction of the liquid chambers are made large, whereby durability can be further improved.

[0046] Further, in this embodiment, regarding a stopper 7 protruding from the inner cylinder 1 in the radial direction, an inner metal portion 71 and an outer rubber portion 72 are formed large in their circumferential width, so that the durability can be improved.

[0047] Also in this second embodiment, by attaching the body mount as shown in FIG. 10 and using it similarly to in the first embodiment, by the effect of the rubber films forming the respective end walls 40a, 41a; 40b, 41b in the axial direction of both the liquid chambers 4a, 4b, the moving spring constant can be reduced, and the vibration damping effect can be also heightens in cooperation with the liquid fluid effect between the liquid chambers 4a and 4b. Further, since the rubber film forming the aforesaid end wall is formed nearly in the wavy shape, the free length of the rubber film is long, and the area of the rubber film is large, the durability can be also improved greatly.

[0048] For example, in case that a bench test corresponding to real car run was compared between the body mount in this second embodiment in which the end wall in the axial direction of the liquid chamber is formed nearly in the wavy shape and the body mount in the first embodiment in which the end wall is formed linearly, it was found that the body mount in the second embodiment had four times or more as long lifetime as the body mount in the first embodiment had.

[0049] As described above, according to the liquid sealing type body mount of the invention, by using it with the axial center positioned in the vertical direction and with the two liquid chambers positioned in the front and back direction of the vehicle, in the front and back directions where the large vibration is applied at the accelerating time such as the vehicle starting time or at the braking time, the moving spring constant of about 100 Hz can be reduced to as low as about 1000 N/mm even in case that the damping coefficient with the frequency of 15 Hz is set to about 4 N·s/mm, so that the large vibration damping effect and the sufficient vibration-proof characteristic can be obtained. Particularly, in case that the rubber film forming the end wall in the axial direction of the liquid chamber is formed nearly in the wavy shape, the durability can be also improved.

Claims

1. A liquid sealing type body mount comprising an inner cylinder fixed to one of a body of a vehicle and a frame on the support side, an outer cylinder fixed to the other of them, a rubber elastomer that is provided between these inner and outer cylinders and couples them to each other elastically, two liquid chambers, which are formed at portions of this rubber elastomer opposed to each other with said inner cylinder between and formed between the inner and outer cylinders, and an orifice passage for communicating these liquid chambers with each other, in which the load of the body is input in the axial direction, characterized in that: end walls in the axial direction in said liquid chambers are formed of a rubber film being a part of said rubber elastomer, and the rubber film is formed aslant and outward in the axial direction from said inner cylinder side toward the outer cylinder.

2. The liquid sealing type body mount according to claim 1, wherein an angle of inclination of the end wall composed of said rubber film in relation to the axial center is 15° to 70°.

3. The liquid sealing type body mount according to claim 1, wherein the end wall composed of said rubber film extends from the inner cylinder side nearly in the wavy shape, and the closer to the outer cylinder side the end wall is, the more it is expanded outward in the axial direction.

4. The liquid sealing type body mount according to any one of claims 1 to 3, wherein the thickness of the end walls composed of said rubber film is 2-6 mm.

5. The liquid sealing type body mount according to any one of claims 1 to 3, wherein stoppers extruding from the inner cylinder in the radial direction are provided in both said liquid chambers.

6. The liquid sealing type body mount according to claim 5, wherein said stopper is formed by embedding a metal portion fixed to the inner cylinder in a rubber portion formed integrally with the rubber elastomer.

7. The liquid sealing type body mount according to any one of claims 1 to 3, wherein an opening angle in the circumferential direction of said liquid chamber is not less than 60° and not more than 140°.