JP2012193756A - Vibration control bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration control bush 10 capable of obtaining sufficient vibration control effects by a lower spring constant even under a condition where a sufficient radial dimension of a bush body 13 cannot be secured by restrictions on design.SOLUTION: The vibration control bush includes the bush body 13 constituted of an outer ring 11, an inner ring 12 concentrically disposed on the inner periphery thereof, and a rubber elastic material interposed between the outer ring 11 and the inner ring 12. In the bush body 13, a plurality of boring holes 13a are opened in the circumferential direction. A portion between the boring holes 13a, 13a adjacent to each other in the circumferential direction in the bush body 13 forms an elastic leg part 131 connecting between positions on each of the inner peripheral sides and on each of the outer peripheral sides, these positions being shifted in vibration phase by just a prescribed phase.

Description

  The present invention relates to an anti-vibration bush, for example, suitable as an anti-vibration means for an outboard motor or other vibration source for propelling the hull of a small vessel.

  In a small vessel, an anti-vibration bush is attached to a swivel mechanism that connects a hull and an outboard motor that propels the hull so as to be capable of turning. FIG. 6 is a cross-sectional view showing a conventional anti-vibration bush together with a part of a swivel mechanism of a small vessel.

  In FIG. 6, reference numeral 201 is a tubular swivel housing that is attached to the stern of the hull via a swivel bracket 202, and reference numeral 203 is rotatable around an axis within the swivel housing 201 via a vibration isolating bush 100. The swivel shaft inserted in a clean state, reference numeral 204 is a handle attached to the upper end 203a of the swivel shaft 203 via the handle bracket 204a, and reference numeral 205 is inserted into the inner peripheral hole of the hollow swivel shaft 203 and is not This is a shift rod for switching the forward / reverse switching gear shown in the figure.

  The anti-vibration bush 100 is concentrically arranged on the inner periphery of the outer sleeve 101 fitted to the upper end portion of the swivel housing 201, and the boss portion of the handle bracket 204a or the upper end portion 203a of the swivel shaft 203 is slidable. A cylindrical bush body integrally vulcanized (vulcanized and bonded) with a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity) between the inserted cylindrical slide bearing 102 103.

  That is, the vibration isolating bush 100 allows the swivel shaft 203 to rotate with respect to the swivel housing 201 by the sliding bearing 102 during steering by the handle 204, and the bush main body 103 made of a rubber-like elastic material has an unillustrated outboard motor. The vibration transmission from the engine to the hull side is reduced (see, for example, Patent Document 1 below).

JP 2005-335605 A

  However, the anti-vibration bush 100 used in this type of small ship swivel mechanism is subject to restrictions in the design area, and may not exhibit a sufficient anti-vibration effect. In many cases, the outer diameter of the swivel housing 201 is restricted. As a result, the outer diameter of the outer sleeve 101 of the vibration isolating bush 100 is restricted, and a sufficient radial thickness of the bush body 103 made of a rubber-like elastic material is ensured. For this reason, the low spring effective for vibration isolation cannot be achieved.

  The present invention has been made in view of the above points, and its technical problem is due to the reduction of the spring even under conditions in which a sufficient radial dimension of the bushing body cannot be secured due to design constraints. An object of the present invention is to provide an anti-vibration bush capable of obtaining a sufficient anti-vibration effect.

  As means for effectively solving the technical problem described above, a vibration isolating bush according to the invention of claim 1 includes an outer ring, an inner ring arranged concentrically on the inner periphery thereof, and the outer ring and the inner ring. A bushing body made of a rubber-like elastic material interposed between rings is provided. The bushing body has a plurality of circumferentially-curved holes in the bushing body. These portions constitute elastic leg portions that connect positions shifted by a predetermined phase on the inner peripheral side and the outer peripheral side, respectively. The rubber-like elastic material means a rubber material or a synthetic resin material having rubber-like elasticity.

  In the above configuration, among the elastic legs between the plurality of circumferentially-curved holes in the bushing body, the elastic legs extending in a direction intersecting the direction of displacement caused by the input radial vibration is subjected to shear deformation. As a result, the spring constant is kept low. In addition, since the elastic leg portion extending in a direction substantially parallel to the direction of displacement due to the input radial vibration is subjected to compression-extension deformation, the stress increases nonlinearly with respect to the displacement amount, Acts as a stopper to suppress excessive displacement. Furthermore, all elastic legs are subjected to shear deformation in response to axial vibration input.

  According to a second aspect of the present invention, in the vibration-proof bushing according to the first aspect, the inner ring is formed of a sliding bearing.

  According to a third aspect of the present invention, in the anti-vibration bushing according to the first or second aspect, the axial projection shape of each elastic leg portion forms a meandering shape.

  According to the anti-vibration bush of the first aspect of the present invention, since a plurality of circumferential holes are formed in the bush main body, the bush main body is restricted by the outer diameter like the anti-vibration bush used in the swivel mechanism of a small vessel. Even when a sufficient thickness in the radial direction cannot be ensured, vibration insulation can be improved and excessive displacement can be suppressed.

  According to the vibration isolating bush according to the second aspect of the present invention, the deformation stress of the elastic leg portion in the bush main body is relieved by the rotational displacement of the inner ring formed of the sliding bearing, so that the vibration isolating performance can be improved.

  According to the vibration isolating bushing of the invention of claim 3, the spring constant is further lowered to improve the vibration insulation, and the elastic leg portion is crushed between the outer ring and the inner ring when the amplitude is increased. Even when acting as a stopper for restraining the position, the spring constant rises continuously and gently, so that concentration of stress on the elastic leg portion can be prevented and vibration isolation can be improved.

It is explanatory drawing which shows roughly the relationship between the mounting structure of the outboard motor in a small ship, and the vibration isolating bush which concerns on this invention. It is a perspective view which shows 1st embodiment of the vibration isolating bush which concerns on this invention in a non-mounting state. It is sectional drawing for demonstrating the effect | action by 1st embodiment of the anti-vibration bush which concerns on this invention. It is a perspective view which shows 2nd embodiment of the anti-vibration bush which concerns on this invention in the unmounted state. It is sectional drawing for demonstrating the effect | action by 2nd embodiment of the vibration isolating bush which concerns on this invention. It is sectional drawing which shows the conventional anti-vibration bush with a part of swivel mechanism of a small ship.

  Hereinafter, a preferred embodiment of a vibration-isolating bush according to the present invention will be described in detail with reference to the drawings. First, FIG. 1 is an explanatory view schematically showing a relationship between an outboard motor mounting structure in a small vessel and a vibration isolating bush according to the present invention.

  In FIG. 1, reference numeral 1 is a hull of a small vessel, and reference numeral 2 is an outboard motor. The outboard motor 2 is attached to the stern plate 1 a of the hull 1 via the upper mount 5 and the lower mount 6, the swivel mechanism 4, and the clamp bracket 3.

  An engine 2a (not shown) is accommodated in the upper part of the outboard motor 2, and a propeller 2b is attached to the lower part. The driving force of the engine 2a is a drive shaft 2c, a forward / reverse switching device 2d, and a propeller. It is transmitted to the propeller 2b via the shaft 2e.

  The clamp bracket 3 attaches the outboard motor 2 to the stern plate 1 a by clamping the stern plate 1 a of the hull 1. A tilt shaft 3a having a substantially horizontal axis is inserted into the clamp bracket 3, and the swivel bracket 4a of the swivel mechanism 4 is pivotally connected to the clamp bracket 3 via the tilt shaft 3a.

  The swivel mechanism 4 includes the above-described swivel bracket 4a, a swivel housing 4b provided integrally therewith and extending in the vertical direction, and a swivel shaft 4c inserted into the swivel housing 4b so as to be relatively rotatable.

  A handle bracket 7a for attaching a handle 7 for steering is coupled to an upper end portion of the swivel shaft 4c protruding from the upper end of the swivel housing 4b, and the vibration isolating bush 10 includes an outer peripheral surface of the swivel shaft 4c and a swivel housing. It is interposed between the inner peripheral surface of 4b.

  FIG. 2 is a perspective view showing the anti-vibration bush 10 according to the first embodiment of the present invention, and FIG. 3 is a sectional view of the same. That is, the anti-vibration bush 10 includes an outer ring 11 that is press-fitted and fixed to an inner peripheral surface of an upper end portion of the swivel housing 4b (see FIG. 1), a sliding bearing 12 that is disposed concentrically on the inner periphery, and the outer bearing 11 A bush body 13 made of a rubber-like elastic material (rubber material or a synthetic resin material having rubber-like elasticity) interposed between the ring 11 and the slide bearing 12 is provided. The inner peripheral surface of the slide bearing 12 is slidably fitted to the outer peripheral surface of the swivel shaft 4c.

  The bush body 13 is configured by concentrically setting the outer ring 11 and the slide bearing 12 in a mold (not shown), and in a cavity defined by the mold between the outer ring 11 and the slide bearing 12. The unvulcanized rubber material is filled, heated and pressurized, and vulcanized and bonded to the inner peripheral surface of the outer ring 11 and the outer peripheral surface of the slide bearing 12 simultaneously with vulcanization molding.

  The bush main body 13 is provided with a currant hole 13a at six circumferential intervals (60 degree intervals). For this reason, the bush main body 13 has elastic leg portions 131 that communicate between the positions where the portions between the curly holes 13a, 13a adjacent in the circumferential direction are shifted by a predetermined phase on the inner peripheral side and the outer peripheral side, respectively. It is what makes. The portion of the bush body 13 on the inner peripheral side of the curly hole 13a is a boss portion 132 that is vulcanized and bonded to the outer peripheral surface of the sliding bearing 12, and the portion on the outer peripheral side of the curly hole 13a is the outer periphery. The film portion 133 is formed. Each elastic leg 131 extends in a substantially tangential direction with respect to the circumference of the boss 132, and the elastic leg 131 as a whole has a substantially spiral shape.

  Moreover, the volume (volume) of the end portion (outer diameter end portion) 131a on the outer ring 11 side and the end portion (inner diameter end portion) 131b on the sliding bearing 12 side in each elastic leg portion 131 is large.

  In the outboard motor mounting structure shown in FIG. 1, the outboard motor 2 can be tilted up and down (tilted up and tilted down) about the tilt shaft 3 a and centered on the swivel shaft 4 c in the swivel mechanism 4. It can turn. Further, in the vibration isolating bush 10 according to the present invention, the cylindrical inner peripheral surface of the sliding bearing 12 is slidably fitted to the outer peripheral surface of the swivel shaft 4c, and the outer ring 11 is connected to the swivel housing 4b. By being press-fitted into the inner peripheral surface, the swivel housing 4b and the swivel shaft 4c are interposed.

  When vibration in the radial direction from the engine 2a of the outboard motor 2 is input to the swivel shaft 4c, the vibration isolating bush 10 is located between the sliding bearing 12 on the swivel shaft 4c side and the outer ring 11 on the swivel housing 4b side. The bush body 13 that undergoes repetitive deformation at has a low spring constant due to having the curly holes 13a. For this reason, even if the outer diameter of the outer ring 11 of the anti-vibration bushing 10 is restricted by restricting the outer diameter of the swivel housing 4b in the design of the ship, the radial dimension of the bushing body 13 cannot be increased. Vibration transmission to the swivel housing 4b side (the hull 1 side) can be effectively reduced.

Specifically, when the relative displacement between the sliding bearing 12 and the outer ring 11 occurs in the direction indicated by the arrow V in FIG. 3 due to the vibration input, the vibration displacement of the six elastic legs 131 between the curly holes 13a. elasticized leg ₁₃₁ 1 extending substantially parallel to the direction V, 131 ₄ compression - becomes a pulling direction, the elastic leg ₁₃₁ 2 extending in a direction intersecting the direction V of the vibration _{displacement,} 131 _3, 131 5, 131 ₆ Since it is almost shear deformation, the spring constant is remarkably low for vibration displacement with a relatively small amplitude, and therefore excellent vibration insulation can be exhibited.

In addition, since the elastic legs 131 ₁ and _{13 4} extending substantially parallel to the vibration displacement direction V receive vibration displacement by compression-tensile, the spring constant increases nonlinearly as the amplitude increases, and the increase in amplitude is suppressed. . Moreover, when the amplitude becomes larger than a predetermined value, the outer diameter end portions 131a and inner diameter end portions 131b of the elastic leg portions 131 ₂ and 131 ₃ or the elastic leg portions 131 ₅ and 131 _{6 in the} direction of the arrow V as viewed from the boss portion 132. The outer diameter end portion 131 a and the inner diameter end portion 131 b of the bush body 13 are crushed in contact with a part of the outer peripheral surface of the boss portion 132 and a part of the inner peripheral surface of the outer peripheral film portion 133, thereby reducing the spring constant. Since it further rises, the increase in amplitude is effectively limited and the deformation of the bush body 13 is suppressed. At this time, since the rubber-like elastic materials are in contact with each other, generation of contact sound is suppressed.

  In addition, the repeated deformation of the elastic legs 131, 131,... Causes the slide bearing 12 to be slightly rotated repeatedly, thereby relieving the stress generated in the elastic legs 131, 131,. At the same time, a sudden change in the spring constant is alleviated.

When the relative displacement between the sliding bearing 12 and the outer ring 11 occurs in the axial direction (direction orthogonal to the cross section of FIG. 3) due to vibration input, all the elastic leg portions 131 _{1 to} 13 ₁₆ undergo shear deformation. Therefore, it is possible to exhibit excellent vibration insulation against axial vibration.

  FIG. 4 is a perspective view showing an anti-vibration bush 10 according to the second embodiment of the present invention, and FIG. 5 is a sectional view of the same. In the second embodiment, the difference from the first embodiment described above is that the projected shape in the axial direction of the elastic leg 131 in the bush body 13 has a meandering shape, and the boss portion in the bush body 13. The surface of 132 and the outer peripheral film part 133 is to form a concave and convex shape opposite to each other in the radial direction and the concave and convex parts of the elastic leg part 131 having a meandering shape. Other configurations are basically the same as those shown in FIGS.

That is, according to the second embodiment shown in FIG. 4 and FIG. 5, the elastic projection extending in the axial direction of the elastic leg 131 in the bushing body 13 has a meandering shape, thereby elastically extending substantially parallel to the vibration displacement direction V. Since the legs 131 ₁ and _{13 4} are also bent and deformed without being compressed and tensioned, the spring constant can be further reduced to improve the vibration insulation, and the elasticity when the input amplitude is increased. Stress concentration on the leg 131 is less likely to occur.

Further, since the surfaces of the boss part 132 and the outer peripheral film part 133 in the bush main body 13 have an uneven shape that is opposed to the uneven surface of the elastic leg 131 formed in a meandering shape in the radial direction, input vibrations when the amplitude of is greater than a predetermined, elasticized leg ₁₃₁ 2 when viewed from the boss portion 132 of the bushing body 13 is in the direction of arrow V, 131 ₃ or elasticized leg ₁₃₁ 5, 131 ₆ boss 132 and the outer membrane In the process of being crushed between the portions 133, the convex surfaces are crushed in advance, so that the spring constant increases more continuously and gently, and stress concentration on the elastic legs is prevented. Vibration isolation can be improved.

  Although the first and second embodiments described above are used for the mounting portion of the outboard motor in a small boat, the present invention can also be applied as a vibration isolation means for other vibration generation sources. .

4 Swivel mechanism 4b Swivel housing 4c Swivel shaft 10 Anti-vibration bush 11 Outer ring 12 Sliding bearing (inner ring)
13 Bush body 13a Currant holes 131, 131 _{1 to} 131 ₆ Elastic leg portion 132 Boss portion 133 Outer peripheral membrane portion

Claims (3)

  An outer ring, an inner ring concentrically disposed on the inner periphery thereof, and a bushing body made of a rubber-like elastic material interposed between the outer ring and the inner ring. Elastic leg portions that connect the positions where the portions between the curly holes adjacent in the circumferential direction of the bush body are shifted by a predetermined phase on the inner peripheral side and the outer peripheral side, respectively. Anti-vibration bush characterized by   The anti-vibration bush according to claim 1, wherein the inner ring comprises a sliding bearing.   The anti-vibration bush according to claim 1 or 2, wherein the projected shape in the axial direction of each elastic leg portion has a meandering shape.

Images