JP2010078101A - Vibration control rubber bush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration control rubber bush easily pressed in a metallic mating member in a resin outer cylinder, and formable in a firmly fixing state in both the axial direction and the rotational direction after being pressed in. <P>SOLUTION: The vibration control rubber bush 10 includes the cylindrical resin outer cylinder 12, a rigid inner cylinder 14 and a rubber elastic body 16, and is formed by arranging a pair of boring parts in the P<SB>1</SB>direction of the rubber elastic body 16. In the outer cylinder 12, a pair of circular engaging projections 36 are formed at an outer peripheral surface in the P<SB>2</SB>direction, and these parts are fitted in a pair of circular engaging recessed parts of a metallic cylindrical mating member when pressing in the outer cylinder 12, and engaged in a position fixing state in the axial direction and the peripheral direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an anti-vibration rubber bush, and more particularly to a technical means for preventing the anti-vibration rubber bush from coming off from the mating member after being assembled by press-fitting into a metal cylindrical mating member. It relates to what you have.

  Conventionally, it has a cylindrical rigid outer cylinder and an inner cylinder, and a rubber elastic body integrally vulcanized and bonded to elastically connect the outer cylinder and the inner cylinder, and is circular on the outer peripheral surface of the outer cylinder. Anti-vibration rubber bushes that are assembled by press-fitting into a cylindrical metal mating member having an inner peripheral surface, and that act as anti-vibration action based on elastic deformation of the rubber elastic body. Is widely used.

  Conventionally, the outer cylinder of the anti-vibration rubber bush is made of metal, and when the anti-vibration rubber bush is press-fitted into the mating member with a predetermined tightening at the outer peripheral surface of the metal outer cylinder, the outer circumference of the outer cylinder Based on the strong frictional force generated between the surface and the inner peripheral surface of the mating member, the anti-vibration rubber bush is prevented from coming off from the mating member and prevented from rotating.

  By the way, in recent years, for the purpose of reducing the weight of the anti-vibration rubber bush, it has been studied to make the outer cylinder resin. In this case, the outer cylinder of the anti-vibration rubber bush is simply press-fitted into the mating member and assembled. That is, when the anti-vibration rubber bush is simply fixed to the mating member only by the frictional force between the outer peripheral surface of the resin outer cylinder and the inner peripheral surface of the mating member, it was initially press-fitted with a predetermined tightening allowance. However, when the resin outer cylinder changes with time and the elastic restoring force is lowered, the fixing force is weakened, and the vibration isolating rubber bush is likely to be displaced with respect to the mating member or easily detached.

An example of a countermeasure for this problem is disclosed in Patent Document 1 below.
FIG. 9 shows a specific example.
In the figure, reference numeral 200 denotes a vibration isolating rubber bush, which is a resin-made outer cylinder 202 having a cylindrical shape, a metal inner cylinder 204, and the outer cylinder 202 and the inner cylinder 204 are integrally vulcanized and bonded to each other. The rubber elastic body 206 is provided.

Reference numeral 208 denotes a mating member made of a metal cylinder having a circular inner peripheral surface. The anti-vibration rubber bush 200 is press-fitted in the axial direction into the mating member 208 on the outer peripheral surface of the outer cylinder 202 and is fitted. Held in a state.
The resin-made outer cylinder 202 has an annular flange 210 on one end side in the axial direction (lower end side in the figure), and the contact of the flange 210 with the shaft end surface of the mating member 208 causes the 9 is prevented from coming off the anti-vibration rubber bush 200 upward.

  The outer cylinder 202 is also provided with inclined surfaces 214 and 216 which are inclined in opposite directions to each other at the other axial end opposite to the outer cylinder 202 and projecting from the mating member 208 in the axial direction. After the vibration-proof rubber bush 200 is press-fitted into the mating member 208, the engaging portion 218 is the shaft end surface of the mating member 208, specifically the flange 210. The anti-vibration rubber bush 200 is prevented from coming off from the mating member 208 in the downward direction in FIG. 9 by engaging with the opposite shaft end surface.

  However, in the device disclosed in Patent Document 1, the anti-vibration rubber bushing 200 is not specifically stopped with respect to the mating member 208, and the resin outer cylinder of the anti-vibration rubber bushing 200 press-fitted into the mating member 208 is used. When the elastic restoring force of 202 decreases due to stress relaxation, there is a risk that the vibration isolating rubber bush 200 rotates relative to the counterpart member 208.

In the case of the anti-vibration rubber bush 200 shown in FIG. 9, a part of the outer cylinder 202, more specifically, the engaging part 218 protrudes from the mating member 208 in the axial direction and is exposed to the outside and exposed to the outside air. Therefore, in addition to the problem of being easily deteriorated, there is a problem that a stepping stone or the like protrudes from the mating member 208 and hits a stepping stone or the like to cause a crack.
Furthermore, in the case of the vibration-insulating rubber bush 200, the axial length must inevitably be longer than that of the counterpart member 208, and there is a problem that the shape is restricted.

  On the other hand, in Patent Document 2 below, a protrusion is provided on the outer peripheral surface of the outer cylinder, and this protrusion is engaged with a corresponding recess provided on the inner peripheral surface of the counterpart member to prevent the vibration isolating rubber bush from coming off the counterpart member. The point made to do is disclosed.

  However, the one disclosed in Patent Document 2 is a divided type in which the outer cylinder is divided into two in the direction perpendicular to the axis, and the engagement force between the projection of the outer cylinder and the recess of the mating member is not the elastic restoring force of the outer cylinder. This is obtained by an elastic restoring force by a rubber elastic body, which is different from the present invention. Further, this Patent Document 2 does not describe the material of the outer cylinder and is different from the present invention.

In addition, in Patent Document 3 below, a recess is provided in a resin outer cylinder, and after the vibration-proof rubber bush is press-fitted into the mating member, the mating member is projected radially inward at a position corresponding to the recess, It is disclosed that the anti-vibration rubber bush is prevented from coming off by engaging the protrusion and the recess of the outer cylinder.
However, in the device disclosed in Patent Document 3, the protrusion on the counterpart member side is not formed in advance before the vibration-insulating rubber bush is press-fitted, and this is also different from the present invention.

Further, in Patent Document 4 below, a concave portion is provided on the inner peripheral surface of the mating member, and a stepped portion is formed on the inner peripheral surface of the mating member by forming the concave portion. By press-fitting the cylinder into the mating member, the outer cylinder has a stepped shape that follows the shape of the outer peripheral surface of the mating member with elastic restoring force, thereby preventing the vibration isolating rubber bush from coming off the mating member. This point is disclosed.
However, in this case, the processing for the mating member becomes troublesome, and this becomes a factor for increasing the cost.

Japanese Utility Model Publication No. 5-77737 Japanese Utility Model Publication No. 56-168403 JP-A-3-89036 JP 2004-176803 A

  In the present invention, against the background as described above, a vibration-proof rubber bush having a resin outer cylinder can be easily press-fitted into a metal mating member, and after the press-fitting, the vibration-proof rubber bush is used as a mating member. On the other hand, an object of the present invention is to provide an anti-vibration rubber bush that can be firmly fixed in the axial direction as well as in the rotational direction and that can sufficiently exhibit the original anti-vibration function of the anti-vibration rubber bush. It was made as.

  Thus, according to the first aspect of the present invention, there is provided a cylindrical resin outer cylinder, a rigid inner cylinder, and a rubber elastic body integrally vulcanized and bonded to elastically connect the outer cylinder and the inner cylinder. An anti-vibration rubber bush that is pressed and assembled in an axial direction into a cylindrical metal counterpart member having a circular inner peripheral surface on the outer peripheral surface of the outer cylinder, and the rubber elastic body includes: At least a pair of straight portions extending in the axial direction are provided in a state perpendicular to each other with the inner cylinder interposed therebetween in the direction perpendicular to the axis, and in the direction perpendicular to the axis perpendicular to the opposing direction of the pair of straight portions, A space between the cylinder and the inner cylinder is a solid part filled with the rubber elastic body, and the outer cylinder has an axial right angle perpendicular to the intermediate part between both ends in the axial direction and the facing direction of the straight part. A pair of circular engagement protrusions protruding from the outer peripheral surface of the outer cylinder in the direction The engaging protrusions are formed on a pair of circular engaging recesses corresponding to the pair of engaging protrusions provided on the inner peripheral surface of the cylindrical member. It is characterized by being engaged and engaged in a fixed position in each of the axial direction and the rotational direction.

  According to a second aspect of the present invention, in the first aspect of the present invention, the engaging protrusion includes a protruding tip having a small diameter with respect to the engaging recess and a proximal end having a larger diameter than the engaging recess. The outer peripheral surface of the engagement protrusion has a shape that gradually increases in diameter from the distal end toward the base end, and when the engagement protrusion is engaged with the engagement recess, the outer peripheral surface is A corner portion on the inner peripheral surface side of the mating member in the engaging recess is brought into contact and pressed over the entire circumference based on the elastic restoring force of the outer cylinder.

  According to a third aspect of the present invention, in the second aspect, the outer peripheral surface of the engaging protrusion bites into a corner portion on the inner peripheral side of the counterpart member.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the outer peripheral surface of the outer cylinder is provided with a recess that surrounds the engagement protrusion in a ring shape that is recessed radially inward. It is characterized by that.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the outer cylinder is provided with an annular collar on one end side in the axial direction, and a convex or An engaging portion having a concave shape is provided.

Effects and effects of the invention

  In the present invention, when an anti-vibration rubber bush is axially press-fitted into the inner peripheral surface of a metal cylindrical mating member on the outer peripheral surface of the resin outer cylinder (the outer diameter of the outer cylinder is smaller than the inner diameter of the mating member). The outer diameter of the mating member is larger than the inner diameter of the mating member), and the pair of engaging projections projecting radially outward from the outer peripheral surface is accompanied by elastic deformation of the outer cylinder. Riding on the inner peripheral surface side and reaching the position of the pair of engaging recesses of the mating member, the pair of engaging protrusions engages (fits) into the corresponding engaging recesses, Therefore, the resin-made outer cylinder, that is, the vibration isolating rubber bush is engaged with the mating member in the axial direction and the rotational direction, and is fixed in the axial direction and the rotational direction with respect to the mating member.

  Thus, when the pair of engaging protrusions ride on the inner peripheral surface side of the mating member, a resistance force acts against the press-fitting of the vibration isolating rubber bush. Further, stress is applied to each engaging protrusion due to the load acting on each engaging protrusion, but in the present invention, when the anti-vibration rubber bush is press-fitted due to the presence of these engaging protrusions. This increases the resistance force, and can suppress the stress acting on the engaging protrusion as small as possible.

The rubber elastic body is provided with a pair of straight portions facing each other with the inner cylinder in the direction perpendicular to the axis, and the rubber elastic body is provided between the outer cylinder and the inner cylinder in the direction perpendicular to the axis perpendicular to the rubber elastic body. In the anti-vibration rubber bush that is filled with solid parts, the resin outer cylinder is radially inward in the solid part due to the shrinkage of the rubber elastic body by cooling after vulcanization. It is pulled greatly, and the tensile force is weakened at the part where the straight part is located.
As a result, the resin-made outer cylinder whose initial cross-sectional shape was a perfect circle shape becomes an elliptical shape as a whole.
Specifically, the shape is an elliptical shape in which the facing direction of the straight portion is the minor axis direction, and the direction orthogonal to this, that is, the direction connecting the solid portions buried with the rubber elastic body is the major axis direction.

In the present invention, since the pair of engaging protrusions are provided on the outer peripheral surface of the outer cylinder in the direction orthogonal to the facing direction of the straight part, that is, in the direction perpendicular to the axis connecting the solid part, When press-fitting in the axial direction, the resistance caused by the pair of engaging protrusions can be made as small as possible, and the stress applied to each engaging protrusion can be made as small as possible.
As a result, the anti-vibration rubber bush can be smoothly press-fitted in the axial direction with respect to the cylindrical mating member regardless of the presence of the pair of engaging protrusions.

Thus, during the press-fitting, the outer cylinder of the anti-vibration rubber bush once formed into an elliptical shape is gradually pushed from the front end side of the press-fitting side into the circular inner peripheral surface of the counterpart member as it is press-fitted in the axial direction with respect to the counterpart member. Follow the above to make a perfect circle.
Accordingly, when the press-fitting is completed, the portion of the outer cylinder provided with the pair of engaging protrusions is also formed into a perfect circle, and the pair of engaging protrusions are pushed outward in the radial direction due to the perfect circular shape. Then, each of the pair of engaging recesses provided on the partner member side is deeply engaged (inserted) to the target position.

That is, since the resin outer cylinder has a shorter diameter in the direction connecting the pair of engaging protrusions, a large resistance force does not work even when the pair of engaging protrusions run on the inner peripheral surface side with respect to the counterpart member. Therefore, the stress acting on the pair of engaging protrusions is also reduced.
As a result, the anti-vibration rubber bushing can be satisfactorily pressed into the mating member to the final assembly position despite the presence of the pair of engaging protrusions.

The present invention also has the following other advantages by providing the pair of engaging protrusions on the outer peripheral surface of the outer cylinder in the direction perpendicular to the axis perpendicular to the facing direction of the straight portion.
If a pair of engaging protrusions are provided in a projecting shape on the outer peripheral surface of the resin outer cylinder in the direction perpendicular to the axis of the straight part, that is, outside the direction perpendicular to the axis of the straight part, the outer cylinder is used as a mating member. When stress is applied to the engaging protrusion from the mating member during press-fitting, the outer cylinder is made of a hollow portion in the radially inner portion of the engaging protrusion from the resin outer cylinder. However, there is a problem that local deformation is likely to occur, and cracks are likely to occur in the outer cylinder based on the deformation.

  However, in the present invention, the pair of engaging protrusions are formed in the outer cylinder in the direction perpendicular to the facing portion and the direction perpendicular to the axis, that is, in the direction connecting the solid part between the outer cylinder and the inner cylinder filled with the rubber elastic body. Since the resin outer cylinder is supported and backed up by a rubber elastic body from the inside when an inward force is applied to these engaging projections during press-fitting, it is locally supported. As a result, it is possible to effectively prevent the resin outer cylinder from being cracked.

Thus, the anti-vibration rubber bush that has been press-fitted to the final assembly position is in a state where the pair of engaging projections are engaged with the engaging recesses of the mating member both in the axial direction and in the rotational direction. The anti-vibration rubber bush can be prevented from being displaced with respect to the mating member in both the direction of removal and the direction of rotation.
The anti-vibration rubber bush has its cross-sectional shape returned to the original perfect circle shape over the entire axial length of the press-fitted portion when the press-fitting is completed.

  In the present invention, the pair of engaging protrusions are provided in an intermediate portion between both ends of the resin outer cylinder, and the engaging protrusions engage with the engaging recesses of the mating member. Therefore, like the conventional vibration-proof rubber bush shown in FIG. 9, the above-mentioned problem due to the resin-made outer cylinder protruding in the axial direction from the mating member can be solved.

In addition, the engaging protrusion and the engaging recess are respectively provided in advance on the resin outer cylinder and the mating member before press-fitting the vibration isolating rubber bush. Therefore, simply press-fitting the vibration isolating rubber bush into the mating member. The engaging protrusion and the engaging recess can be brought into an engaged state.
Therefore, unlike the one disclosed in Patent Document 3, it is not necessary to perform a process of projecting a part of the mating member radially inward after the anti-vibration rubber bushing is press-fitted.
In addition, since the inner shape of the counterpart member does not have to be processed and formed into a complicated shape in advance, the entire vibration isolator including the anti-vibration rubber bush and the counterpart member can be configured at low cost.

  Next, according to a second aspect of the present invention, the engaging protrusion is configured such that the tip on the protruding side has a small diameter with respect to the engaging recess and the base end has a larger diameter than the engaging recess, and the outer peripheral surface of the engaging protrusion is the tip. The diameter gradually increases from the base end toward the base end, and when the engagement protrusion is engaged with the engagement recess, the outer peripheral surface is set to the corner on the inner peripheral surface side of the mating member in the engagement recess. On the other hand, the entire outer circumference is brought into contact and pressed based on the elastic restoring force of the resin outer cylinder.

  If the outer peripheral surface of the engaging protrusion is a surface perpendicular to the axis and the engaging protrusion is engaged with the engaging recess from the base end to the tip end, the engaging protrusion Inevitably, a minute gap is generated in the axial direction and the rotational direction between the outer peripheral surface of the engaging protrusion and the outer peripheral surface of the engaging protrusion and the inner peripheral surface of the engaging concave portion. Due to the gap, the outer cylinder rattles against the mating member or misaligns.

However, according to the second aspect, the base end of the engaging protrusion has a large diameter with respect to the engaging recess, and the outer peripheral surface of the engaging protrusion has a shape gradually increasing from the tip toward the base end. Therefore, when the engaging protrusion is engaged with the engaging recess, the outer peripheral surface is surely connected to the corner on the inner peripheral side of the engaging recess at any part from the tip to the base end. It can be made to contact in a press state without a clearance over the entire circumference.
As a result, the anti-vibration rubber bush can be strictly fixed with respect to the mating member both in the axial direction and in the rotational direction.

Of the outer peripheral surface of the engaging protrusion, the portion that contacts and is pressed against the corner on the inner peripheral side of the engaging recess bites the corner, and under the continuous action of the pressing force, the corner The shape changes to a shape following the portion (claim 3).
Here, the outer peripheral surface of the engaging protrusion can be a curved shape or other shapes, but it is preferable that the outer peripheral surface is a tapered surface.

According to a fourth aspect of the present invention, an annular recess surrounding the engaging protrusion is provided on the outer peripheral surface of the outer cylinder so as to be recessed radially inward.
This recess has mainly the following two meanings.
When the resin outer cylinder is press-fitted into the mating member, stress is applied to the pair of engaging protrusions as described above. At this time, by providing a recess that becomes a weak point of strength so as to surround the engagement protrusion, it promotes local deformation of the engagement protrusion, and thereby releases the stress to the recess, The force applied to the engaging protrusion can be reduced.
Moreover, it can make it easy to ride an engagement protrusion on an inner peripheral side with respect to the other member. That is, the press-fit property of the vibration-proof rubber bush to the mating member can be improved.

According to claim 2, when a part of the outer peripheral surface of the engaging protrusion is brought into contact with the corner on the inner peripheral side of the engaging recess in a pressed state, the engaging protrusion also starts from that corner. Specifically, a large stress is applied to the outer peripheral surface.
At this time as well, the deformation of the outer peripheral portion of the engaging protrusion can be promoted toward the recess, whereby the force applied from the corner of the engaging recess can be reduced.
Furthermore, by letting the flesh of the outer peripheral part of the engaging projection part escape into the hollow part, it is possible to help the shape of the outer peripheral surface to be deformed into a shape that follows the shape of the corner part.

Next, a fifth aspect of the present invention is to provide a flange portion in an annular shape on one end side in the axial direction of the outer cylinder, and to provide a convex or concave engagement portion at a predetermined circumferential position of the flange portion.
In the present invention, when the anti-vibration rubber bush is press-fitted into the mating member, the pair of engaging protrusions must be correctly aligned in the rotational direction with respect to the pair of engaging recesses on the mating member side. If the position is deviated, the engagement protrusion will not be engaged with the engagement recess when the anti-vibration rubber bush is pressed into the mating member.

  Here, according to claim 5, by providing a convex or concave engaging portion at a predetermined position in the circumferential direction of the flange portion of the outer cylinder, the anti-vibration rubber bush is press-fitted into the mating member based on the engaging portion. In this case, positioning in the rotational direction can be performed, and when the vibration isolating rubber bush is press-fitted, the pair of engaging protrusions can be reliably engaged with the engaging recesses of the counterpart member.

The engaging portion also has the following meaning.
When the resin outer cylinder and inner cylinder are set in the mold and the rubber elastic body is vulcanized, the pair of engaging protrusions are positioned correctly in the direction perpendicular to the axis perpendicular to the facing direction of the tick portion. It is necessary to set a resin outer cylinder.

If the position of the outer cylinder in the rotational direction is deviated during the setting, the pair of engaging projections will deviate from the target position in the rotational direction with respect to the rubber elastic body.
Here, the engaging portion provided in the collar portion is used as a positioning portion, and the resin outer cylinder can be positioned at the target rotational direction position with respect to the mold, and the pair of engaging protrusions Can be positioned in a direction perpendicular to the axis perpendicular to the opposing direction.

Next, an embodiment in which the present invention is applied to an anti-vibration rubber bush as a rear trailing arm bush of a vehicle will be described in detail with reference to the drawings.
1 to 4, reference numeral 10 denotes an anti-vibration rubber bush according to the present embodiment, and a cylindrical outer cylinder 12, a cylindrical inner cylinder 14, and the outer cylinder 12 and the inner cylinder 14 are elastically connected to each other. The rubber elastic body 16 is integrally vulcanized and bonded to the state.
The inner cylinder 14 is made of a metal, here, an aluminum alloy extruded material, and has a plurality of voids 18 penetrating in the axial direction along the circumferential direction.

On the other hand, the outer cylinder 12 is made of a resin made of a hard resin. Here, polyamide 66 resin is used as the resin. This polyamide 66 resin contains 33% by mass of glass fiber as a reinforcing material on a polymer basis.
However, the outer cylinder 12 can be made of resin of other materials.
The outer cylinder 12 is integrally formed with a flange portion 20 that is annular in the circumferential direction and projects outward in the radial direction on one end side in the axial direction (right end side in FIG. 3).

The rubber elastic body 16 also has a cylindrical shape around the axis. The rubber elastic body 16 faces each other with the inner cylinder 14 therebetween in the direction perpendicular to the axis as shown in FIGS. In the state, a pair of straight portions 22 having a shape penetrating in the axial direction is provided.
Specifically, the straight portions 22 are provided at two positions that are 180 ° apart in the circumferential direction.
The rubber elastic body 16 is provided with a rubber collar 24 in a state where it overlaps with the collar 20 of the outer cylinder 12 as shown in FIGS. 3 and 4.

Here, the straight portion 22 has a slit-like portion 25 extending in a circular arc shape in the circumferential direction as shown in FIG. 2, and a shape in which the slit-like portion 25 is recessed inward and outward in the radial direction at both ends. And a pair of end portions 26 formed.
Here, the pair of straight portions 22 has a vertically symmetrical shape in FIG.
Further, in each of the straight portions 22, the end portions 26 and the slit-like portions 25 are also symmetrical in FIG.

The rubber elastic body 16 is provided with an inner peripheral rubber stopper portion 28 and an outer peripheral rubber stopper 30 which are opposed to each other in the radial direction with the straight portions 22 therebetween.
When the inner cylinder 14 and the outer cylinder 12 are relatively displaced in the vertical direction in FIG. 2, the inner peripheral rubber stopper 28 and the outer peripheral rubber stopper 30 are in the same direction due to the stopper action caused by their contact. Regulates excessive relative displacement.

Reference numeral 32 denotes a rubber main body part that inherently performs vibration isolation by elastic deformation, and the vibration isolation rubber bush 10 is formed between the outer cylinder 12 and the inner cylinder 14 in a direction perpendicular to the axis perpendicular to the opposing direction of the pair of straight portions 22. The space is filled with the rubber main body portion 32, and the same portion is a solid portion. In the figure, 34 indicates the solid part.
Naozu in P ₁ represents the opposite direction of the hollow portion, also P ₂ represents the direction perpendicular to the axis orthogonal thereto.

The outer cylinder 12 made of resin, the intermediate portion and the above P ₂ direction between axially opposite ends, i.e. in the axis-perpendicular direction orthogonal to the opposing direction of the hollow portion 22, a circular pair projecting from the outer peripheral surface of the outer tube 12 The engaging protrusion 36 is integrally provided.
Specifically, the pair of engaging protrusions 36 are provided to stand up from the outer peripheral surface of the outer cylinder 12 at two positions that are 180 ° apart in the circumferential direction.
The pair of engaging protrusions 36 are arranged so that the vibration isolating rubber bush 10 is axially or rotationally moved relative to the mating member 38 after the vibration isolating rubber bush 10 is press-fitted into the mating member 38 shown in FIG. It works to fix firmly.

The mating member 38 is a metal cylindrical member having a circular inner peripheral surface, and an arm 40 extends from the mating member 38 as shown in FIG.
The mating member 38 is provided with circular and penetrating engagement recesses 42 at two positions in the middle in the axial direction and at a position 180 ° apart in the circumferential direction. Here, the engaging recess 42 is originally provided for positioning when the mating member 38 is welded.
In this embodiment, this is used as an engagement recess 42 for engagement of the engagement protrusion 36 in the vibration isolating rubber bush 10.
The outer cylinder 12 has an outer diameter D ₁ (D ₁ = φ71.9 mm) shown in FIG. 7 with respect to the inner diameter D ₀ (D ₀ = φ69 mm) of the mating member 38 in the shape of the rubber elastic body 16 before vulcanization. The diameter is about 3 mm (strictly, 2.9 mm).

The engagement protrusion 36 provided on the outer cylinder 12 has a circular planar shape as shown in FIG. 6 and a trapezoidal shape as shown in FIG.
Specifically, the engaging protrusion 36 has a circular tip at the protruding end and a base end, and an outer peripheral surface of the engaging protrusion 36 is a tapered surface 44 that gradually increases in diameter from the tip toward the base end.
The diameter d _{1 of the} distal end surface is smaller than the inner diameter d ₀ of the engaging recess 42 of the mating member 38, and the diameter d _{2 of the} proximal end is larger than the inner diameter d ₀ of the engaging recess 42. There is no.

An annular recess 46 surrounding the engaging protrusion 36 is also provided on the outer peripheral surface of the outer cylinder 12 so as to be recessed inward in the radial direction.
In this embodiment, the diameter d ₁ of the front end surface of the engagement protrusion 36 is φ8 mm with respect to the inner diameter d ₀ of the engagement recess 42 = φ10.25 mm, and the diameter of the front end surface is smaller than that of the engagement recess 42. It has a small diameter.
On the other hand, the diameter d ₂ = φ11.5 mm of the base end of the engagement protrusion 36 is larger than the inner diameter d ₀ of the engagement recess 42.
The difference between d ₁ and d ₀ is 2.25 mm, and the difference between d ₂ and d ₀ is 1.25 mm.
Here, the base end of the engaging protrusion 36 is a portion located at the same radial position as the outer peripheral surface of the outer cylinder 12 in the engaging protrusion 36. Q in FIG. 3 represents the base end.
In FIG. 3B, the protrusion height h ₁ of the engaging protrusion is ₁ mm, and the depth h ₂ of the recess 46 is 0.5 mm.

As shown in FIGS. 1 and 3, the flange portion 20 of the outer cylinder 12 has a V shape and a concave shape at two positions spaced 180 ° in the circumferential direction from the outer peripheral end toward the radially inner side. A pair of engaging portions 48 are provided.
These engaging portions 48 are located opposite each other in the P ₁ direction, as shown in FIG.

As described above, before the rubber elastic body 16 is vulcanized, the resin outer cylinder 12 has a perfect circle shape with a diameter D ₁ in both the P ₁ direction and the P ₂ direction as shown in FIG. 7A. There is no.
On the other hand, after the rubber elastic body 16 is vulcanized and molded, the shape of the rubber elastic body 16 becomes elliptical as shown in FIG.

For more information, becomes the P ₂ direction in the drawing an elliptical shape of the shape minor axis direction, the P ₁ direction and major axis direction.
As the show FIG. 7 (B), the engaging projection 36 of the outer peripheral surface of the outer cylinder 12 is positioned on the outer peripheral surface of the outer cylinder 12 at its P ₂ direction or minor axis direction.

Thus the outer cylinder 12 is oval shaped from its original circular shape, in drawing P ₂ direction is without a solid portion 34 which inner portion of the outer cylinder 12 is filled with rubber elastic body, thus whereas acts strongly pulling force inward by the rubber elastic body in the P ₂ direction, in the P ₁ direction, relative tensile force in the radially inward relative to the outer cylinder 12 by the presence of the hollow portion 22 As a result, the outer cylinder 12 becomes elliptical as shown in FIG.

In the present embodiment, the anti-vibration rubber bush 10 is formed in the axial direction from the end opposite to the flange portion 20 inside the mating member 38 shown in FIG. Press fit.
At this time, as the outer cylinder 12 is press-fitted into the mating member 38 from the shaft end side, the shape is restored to a shape that follows the circular inner peripheral surface of the mating member 38, and the shape gradually becomes a perfect circle.
Then, in the final press-fitted state, that is, the assembled state, the press-fitted portion to the mating member 38 has a perfect circle shape over the entire length.

During the press-fitting, a pair of engaging projection 36 which is located P ₂ direction, which is the minor axis direction, after hitting the shaft end of the mating member 38, rides on the inner peripheral side of the mating member 38 Thereafter, the inner peripheral surface of the mating member 38 is moved in the axial direction together with the press-fitting, and reaches the position of the engaging recess 42 of the mating member 38.

At this stage, the pair of engaging protrusions 36 is engaged with the engaging recess 42 and engaged with the engaging recess 42 in both the axial direction and the rotational direction.
At this time, as shown in FIG. 8 (A), the engaging protrusion 36 has a part of the tapered surface 44 on the outer peripheral surface in contact with the corner K on the inner peripheral side of the engaging recess 42 over the entire periphery. And is pressed upward in the figure based on the elastic restoring force of the outer cylinder 12.

That is, at this time, the engagement protrusion 36 is in a state where the tapered surface 44 is in contact with and pressed against the corner K of the engagement recess 42 over the entire circumference.
Thereafter, the engaging projection 36 is deformed into a shape following the corner K at the tapered surface 44, and finally, at the deformed portion as shown in FIG. It will be in the state fitted in the close contact state.

In this embodiment, the recess 46 provided in an annular shape so as to surround the engaging protrusion 36 operates as follows.
That is, the recess 46, which is a strong weak point, allows the stress applied to the engagement protrusion 36 to escape to the recess 46 when the engagement protrusion 36 hits the shaft end of the mating member 38 and rides on the inner peripheral side. As a result, the engaging protrusion 36 can be easily ridden on the inner peripheral side of the mating member 38, and at the same time, the stress applied to the engaging protrusion 36 itself is reduced.

Furthermore, when the engagement protrusion 36 is fitted into the engagement recess 42 of the counterpart member 38 and the tapered surface 44 hits the corner K of the engagement recess 42 (at this time, the outer peripheral surface of the outer cylinder 12 is 8 (A) slightly downward from the inner peripheral surface of the member 38), the deformation of the portion of the tapered surface 44 of the engaging projection 36 is promoted, and a portion of the tapered surface 44 is joined to the corner portion K. Make it easier to become familiar with. That is, it is easy to deform into a shape following this.
The tapered surface 44 of the engagement protrusion 36 changes in shape to follow the corner K, so that the outer peripheral surface of the outer cylinder 12 is the inner surface of the mating member 38 as shown in FIG. It will be in the state which adhered to the peripheral surface.

The pair of engaging portions 48 provided on the flange portion 20 of the outer cylinder 12 serves to position the vibration isolating rubber bush 10 at a target rotational direction position when press-fitting the vibration isolating rubber bush 10 into the mating member 38. .
In addition, when the outer cylinder 12 is set in a mold when the rubber elastic body 16 is vulcanized and formed, the pair of engaging protrusions 36 are opposed to the straight portion 22 of the rubber elastic body 16. as correctly positioned in P ₁ direction and the orthogonal direction, forms serve to position it.

In the present embodiment, when the pair of engaging protrusions 36 ride on the inner peripheral surface side of the counterpart member 38, a resistance force acts against the press-fitting of the vibration isolating rubber bush 10. Further, when a load acts on each engagement protrusion 36, stress acts on each engagement protrusion 36.
However, in the present embodiment, the resistance force when the anti-vibration rubber bush 10 is press-fitted due to the presence of the engagement protrusions 36 is increased, and the stress acting on the engagement protrusions 36 is made as small as possible. Can be suppressed.

Since the present embodiment is located on the short radially (P ₂ direction) of the outer cylinder 12 in which a pair of engaging projection 36 has an elliptical shape by vulcanization molding of the rubber elastic body 16, vibration damping rubber bushing 10 , The resistance caused by the pair of engaging protrusions 36 can be made as small as possible, and the stress applied to each engaging protrusion 36 is made as small as possible. can do.
As a result, the anti-vibration rubber bush 10 can be smoothly press-fitted in the axial direction with respect to the cylindrical counterpart member 38 in spite of the presence of the pair of engaging protrusions 36.

Thus, when the outer cylinder 12 of the anti-vibration rubber bush 10 once elliptically shaped is pressed into the mating member 38 in the axial direction, the circular shape of the mating member 38 is gradually increased from the distal end side of the press-fitting side. It is made into a perfect circle following the inner peripheral surface.
Therefore, when the press-fitting is completed, the portion of the outer cylinder 12 provided with the pair of engaging protrusions 36 is also formed into a perfect circle shape, and the pair of engaging protrusions 36 is radially outward by the circular shape. Are pushed into each of the pair of engaging recesses 42 provided on the side of the mating member 38 to a target position (inserted).

Also in this embodiment, by being provided on the outer peripheral surface of the outer cylinder 12 in the P ₂ direction in FIG. 2 and FIG. 7 a pair of engagement projections 36, Other has the following advantages.
If a pair of engagement projections 36, if provided in the projecting shape on an outer peripheral surface of the resin of the outer tube 12 in the P ₁ direction, when press-fitting the outer tube 12 to the mating member 38, the engaging projection 36 On the other hand, when a stress is applied from the mating member 38, a cavity by the straight portion 22 is generated in the radially inner portion of the engaging projection 36 of the resin outer cylinder 12, so that the outer cylinder 12 is locally There arises a problem that the outer cylinder 12 is likely to be deformed, and the outer cylinder 12 is easily cracked based on the deformation.

However in this embodiment thereof a pair of engagement projections 36 P ₂ direction, that between the outer cylinder 12 and the inner cylinder 14 is in the direction connecting the solid portion 34 filled with the rubber elastic body 16, the outer cylinder 12 Since the resin outer cylinder 12 is supported by the rubber elastic body 16 from the inside and backed up when an inward force is applied to the engaging protrusions 36 during press-fitting, the outer shell 12 is backed up. As a result, the resin outer cylinder 12 is effectively prevented from being cracked.

  In the present embodiment, the pair of engaging protrusions 36 are provided at the intermediate part between both ends of the resin outer cylinder 12, and the engaging protrusions 36 engage with the engaging recesses 42 of the mating member 38. Therefore, unlike the conventional anti-vibration rubber bush 10 shown in FIG. 9, the above-described problem due to the resin-made outer cylinder projecting long in the axial direction from the mating member does not occur.

In addition, the engaging protrusion 36 and the engaging recess 42 are provided in advance on the resin outer cylinder 12 and the mating member 38 before press-fitting the vibration isolating rubber bush 10, respectively. The engagement protrusion 36 and the engagement recess 42 can be brought into an engagement state simply by press-fitting into the member 38.
Therefore, unlike the one disclosed in Patent Document 3, it is not necessary to perform a process of projecting a part of the mating member 38 radially inward after the anti-vibration rubber bush 10 is press-fitted.
In addition, since the inner shape of the counterpart member 38 does not have to be processed and formed in advance in a complicated shape, the entire vibration isolator including the vibration isolating rubber bush 10 and the counterpart member 38 can be configured at low cost.

  Furthermore, in the present embodiment, the engaging protrusion 36 has a protruding tip with a small diameter with respect to the engaging recess 42 and a base end with a larger diameter than the engaging recess 42, and the outer peripheral surface of the engaging protrusion 36. Is formed as a tapered surface 44 that gradually increases in diameter from the distal end toward the proximal end, and is brought into contact with the corner K of the engaging recess 42 in a pressed state over the entire circumference when engaged with the engaging recess 42. Therefore, there is no gap between the engagement protrusion 36 and the engagement recess 42, and therefore the gap causes the outer cylinder 12 to rattle against the mating member 38, or the position shifts. The vibration isolating rubber bush 10 can be strictly fixed to the mating member 38 in the axial direction and also in the rotational direction.

  Furthermore, in this embodiment, since the annular recess 46 serving as a strong weak point is provided on the outer peripheral surface of the outer cylinder 12, when the resin-made outer cylinder 12 is press-fitted into the mating member 38, it is engaged. The protrusion 36 can be easily ridden on the inner peripheral side of the mating member 38, and the press-fitting property of the vibration isolating rubber bush 10 to the mating member 38 can be improved.

  In addition, after the tapered surface 44 of the engaging projection 36 is brought into contact with the corner K of the engaging recess 42 in a pressed state, deformation of the tapered surface 44 toward the recess 46 can be promoted, and On the other hand, the force applied from the corner K can be relaxed.

Although the embodiment of the present invention has been described in detail above, this is merely an example.
For example, the circular engagement protrusion 36 and the engagement recess 42 described above may not be a perfect circle, and the engagement portion 48 may be a concave shape having various shapes other than the V shape. Alternatively, it can be formed in a convex shape. In addition, the present invention can be applied to an anti-vibration rubber bush having no flange 20 and the present invention can be configured in various modifications without departing from the spirit of the present invention.

It is the perspective view which showed the vibration proof rubber bush of one Embodiment of this invention. It is sectional drawing of the axis orthogonal direction of the same embodiment. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is IV-IV sectional drawing of FIG. It is sectional drawing shown in the state which press-fitted the vibration isolating rubber bush of the same embodiment to the other member. It is the figure which showed the dimensional relationship between the engagement protrusion of the outer cylinder of the embodiment, and the engagement recessed part of the other party member. It is explanatory drawing which shows the shape change before and behind vulcanization | cure of the outer cylinder in the same embodiment. It is action | operation explanatory drawing of the taper surface of the engaging protrusion at the time of press-fitting the vibration isolating rubber bush of the embodiment to the other member. It is sectional drawing of a conventionally well-known anti-vibration rubber bush.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Anti-vibration rubber bush 12 Outer cylinder 14 Inner cylinder 16 Rubber elastic body 22 Straight part 34 Solid part 36 Engagement protrusion 38 Opposing member 42 Engagement recessed part 46 Recessed part 48 Engagement part
K corner

Claims (5)

A cylindrical resin outer cylinder, a rigid inner cylinder, and a rubber elastic body integrally vulcanized and bonded in a state of elastically connecting the outer cylinder and the inner cylinder, and an outer peripheral surface of the outer cylinder A vibration isolating rubber bush that is press-fit in an axial direction to a cylindrical metal mating member having a circular inner peripheral surface, and the rubber elastic body has at least a pair of straight portions extending in the axial direction. The rubber is provided between the outer cylinder and the inner cylinder in a direction perpendicular to the direction perpendicular to the opposing direction of the pair of straight portions. It is considered as a solid part buried in the body,
The outer cylinder is provided with a pair of circular engaging projections protruding from the outer peripheral surface of the outer cylinder in a direction perpendicular to the axis perpendicular to the intermediate portion between both axial ends and the facing direction of the straight portion,
The engagement protrusions are engaged with a pair of circular engagement recesses corresponding to the pair of engagement protrusions provided on the inner peripheral surface of the cylindrical counterpart member. An anti-vibration rubber bush characterized by engaging in a fixed position in each of a direction and a rotational direction. 2. The engagement protrusion according to claim 1, wherein a protrusion-side distal end has a small diameter with respect to the engagement recess, and a base end has a larger diameter than the engagement recess, and the outer periphery of the engagement protrusion The surface has a shape that gradually increases in diameter from the distal end toward the proximal end,
When the engagement protrusion is engaged with the engagement recess, the outer peripheral surface is entirely against the corner on the inner peripheral surface side of the mating member in the engagement recess based on the elastic restoring force of the outer cylinder. An anti-vibration rubber bush characterized by being contacted and pressed over the circumference.   3. The anti-vibration rubber bush according to claim 2, wherein the outer peripheral surface of the engaging protrusion bites into a corner portion on the inner peripheral side of the mating member.   4. The anti-vibration method according to claim 1, wherein a hollow portion that annularly surrounds the engaging protrusion is provided in a radially inward shape on the outer peripheral surface of the outer cylinder. Rubber bush.   In any one of Claims 1-4, the said outer cylinder is provided with the collar part cyclically | annularly at the one end side of the axial direction, The engaging part which makes convex shape or a concave shape in the circumferential direction predetermined part of this collar part is provided. An anti-vibration rubber bush characterized by being provided.

Images