JPH04316731A - Slide type rubber bush - Google Patents

Abstract

PURPOSE:To prevent slide resistance from being generated by means of an air pressure in a dust boot with which a slide part is sealed, in a slide type rubber bush rotatable around a support axis and axially slidable. CONSTITUTION:A slide collar 30 is mounted on the inner peripheral surface of an inner cylinder 26 of a rubber bush 5 and rotatable around a support shaft 7 and axially slidable. Gaps between the outer peripheral surfaces of the two end parts of the inner cylinder 26 and the outer peripheral surface of the support shaft 7 are respectively sealed with dust boots 32 and 32. An axial groove is formed in the inner peripheral surface of the inner cylinder 26 and the slide collar 30 is formed in a shape conforming to that of the grooved inner peripheral surface. Thus, a groove is formed in the inner peripheral surface of the slide collar 30 also. An air communicating passage 37 through which spaces in the dust boots 32 and 32 on both sides are intercommunicated is formed by means of the groove.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to rubber bushings used in automobile suspensions, etc.
This invention relates to a sliding rubber bush that is rotatable about a support shaft and slidable in the axial direction.

0002

[Prior Art] In automobile suspensions, rubber bushings are used in links and arm connections placed between the wheels and the vehicle body in order to absorb vibrations transmitted from the wheels to the vehicle body. often. Generally, the rubber bushing is composed of an inner cylinder and an outer cylinder arranged concentrically at intervals, and a rubber-like elastic body installed between the inner and outer cylinders. The rubber-like elastic body is vulcanized and bonded to the inner cylinder and the outer cylinder, respectively. The inner cylinder is fitted onto and supported by a support shaft attached to the vehicle body or wheel side, and the outer cylinder is fixed to the other side. When such a rubber bush is used in a suspension, the inner cylinder is usually fixed to the support shaft. In this way, when the wheel is displaced with respect to the vehicle body, the inner cylinder and the outer cylinder of the rubber bush are relatively displaced in the radial direction, circumferential direction, or axial direction, and the rubber-like elastic body becomes elastic with the relative displacement. As it deforms, its elasticity allows it to absorb vibrations in various directions.

By the way, as a rear suspension for an automobile, one in which the posture of a wheel during bump rebound is controlled by one trailing arm and three lateral links is known. In this rear suspension, a wheel support section is provided on the rear end side of a trailing arm that is arranged in the longitudinal direction of the vehicle body and whose front end side is connected to the vehicle body in a vertically swingable manner, and the wheel support section allows the wheels to rotate freely. Supported. Both ends of the three lateral links arranged in the left-right direction of the vehicle body are each swingably connected to the trailing arm and the vehicle body. Further, a suspension spring is provided between the rear end side of the trailing arm and the vehicle body to absorb vertical movement of the wheels. According to such a rear suspension, the longitudinal position of the wheel is regulated by the trailing arm, and at the time of bump rebound, the trailing arm swings vertically around the vehicle body side connection part on the front end side. This allows the wheels to move up and down. The camber and toe angle of the wheel at that time are determined by the three lateral links. Therefore, it becomes easy to set the attitude of the wheel during bump rebound, and the ride comfort and maneuverability of the vehicle can be further improved.

In addition, in the case of a suspension that uses three lateral links, by arranging the lateral links front and rear apart, toe rigidity can be increased, and the attitude of the wheel due to side force can be increased. change can be prevented. Further, by arranging the front lateral link near the connecting portion of the trailing arm on the vehicle body side, the lateral link can be shortened, and the entire suspension can be made lighter and more compact. From this point of view, a rear suspension was proposed in which the front end of the trailing arm extends further forward than the connecting part on the vehicle body side, and one of the three lateral links is connected to this extended part. (Unexamined Japanese Patent Publication No. 1983)
(Refer to Publication No.-6806).

[0005] In such a suspension, the longitudinal impact force applied to the wheels is transmitted to the vehicle body via the trailing arm. Therefore, in order to improve compliance by absorbing the impact force, a rubber bush is generally used at the vehicle body side connecting portion of the trailing arm. In that case, if one of the three lateral links is connected to the front end side extension of the trailing arm as described above, the posture of the trailing arm as seen in the plan view is determined by the front end side lateral link. As a result, when the trailing arm swings up and down, a large displacement in the left-right direction of the vehicle body may occur at the connecting portion of the trailing arm on the vehicle body side. For this reason, if a conventional rubber bush is used at the vehicle body side connection part, in which the inner and outer cylinders are fixed to the vehicle body and the trailing arm, respectively, a large axial load will be applied to the rubber-like elastic body between the inner and outer cylinders. This causes a problem in that the rubber-like elastic body tends to deteriorate. Moreover,
Since the elasticity of the rubber-like elastic body acts as a resistance to the displacement of the trailing arm, the posture of the wheel cannot be controlled smoothly by the lateral link, and the riding comfort against bump rebound deteriorates.

[0006] In addition, in the case of a suspension that uses such a rubber bush at the connecting portion of the trailing arm on the vehicle body side, when a vertical force is applied to the wheel and the trailing arm swings in the vertical direction, Since the inner and outer cylinders of the rubber bush rotate relative to each other, the rubber-like elastic body between the inner and outer cylinders is elastically deformed in the circumferential direction. However, since the vertical force applied to the wheel is elastically supported by the suspension spring, there is no need for the rubber bush to have cushioning properties against the vertical swing of the trailing arm. If the rubber-like elastic body is elastically deformed even when the trailing arm swings up and down, shearing force will always be applied to the rubber-like elastic body, which will cause the rubber-like elastic body to deteriorate more easily. . Therefore, the durability of the rubber bushing decreases.

[0007] Therefore, in the case of the above-mentioned suspension, it is desirable to make the rubber bush used at the vehicle body side connection part of the trailing arm rotatable with respect to the support shaft and slidable in the axial direction. desired. As such a sliding rubber bush,
There is one such as shown in Publication No. 348. In this rubber bush, the inner cylinder is a sliding sleeve made of a material with a small coefficient of friction, and the sliding sleeve is fitted and supported by a support shaft. If such a sliding rubber bush is used, displacement of the trailing arm in the left-right direction of the vehicle body will be allowed without resistance, so that the attitude control of the wheel by the lateral link will be performed smoothly. Also, when the trailing arm swings up and down, the inner cylinder of the rubber bush rotates with respect to the support shaft, which prevents unnecessary loads from being applied to the rubber-like elastic body between the inner cylinder and the outer cylinder. This improves the durability of the rubber bushing.

By the way, when the inner cylinder of the rubber bushing is made to be able to slide on the support shaft, water, dust, etc. may enter the sliding part between the inner cylinder and the support shaft. In order to prevent the sliding resistance from increasing, it is necessary to hermetically shield the sliding portion from the outside. When sealing a sliding part in this way, generally, as shown in the above publication, dust boots are provided on both sides of the rubber bush in the axial direction, so that the space between the rubber bush and the support shaft is airtightly covered. do. The dust boot is made of an airtight and flexible material, and one end is airtightly attached to the inner cylinder side of the rubber bushing, and the other end is closely fixed to the outer peripheral surface of the support shaft.

[0009]

[Problems to be Solved by the Invention] However, in the case of a sliding rubber bush used for a trailing arm of a suspension, in order to prevent rattling etc., the inner diameter of the inner cylinder is the same as the outer diameter of the support shaft. They are required to have approximately the same diameter. Therefore, the internal spaces of the dust boots attached to both sides of the rubber bushing are almost hermetically sealed. Then, when the rubber bush slides in the axial direction with respect to the support shaft, one dust boot is compressed and the other dust boot is tensed, so the internal space of one dust boot becomes high pressure and the other dust boot A difference occurs between the pressure inside the boot and the pressure inside the boot. This difference in pressure between the dust boots on both sides creates resistance to sliding of the rubber bushing. Therefore, when used in the suspension as described above, the sliding resistance prevents smooth displacement of the trailing arm, resulting in a decrease in ride comfort.

The present invention has been made in view of these problems, and its object is to provide a slide type rubber bushing as described above in which both sides in the axial direction are hermetically sealed by dust boots. The object is to allow sliding in the direction without resistance.

[0011]

[Means for Solving the Problems] In order to achieve this object, the present invention provides a pair of dust boots that airtightly seal between both ends of the inner cylinder of the rubber bush in the axial direction and the outer peripheral surface of the support shaft. The internal spaces are communicated with each other through air communication passages. The air communication path is configured, for example, by forming a groove extending in the axial direction on the inner circumferential surface of the inner cylinder, and forming a groove shaped along the groove on a sliding collar attached to the inner circumferential surface. Ru. When the sliding collar is formed by abutting both ends of a flat plate member to form a cylindrical shape, the abutting portion is positioned within a groove in the inner peripheral surface of the inner cylinder.

0012

[Operation] With this configuration, when the rubber bush slides in the axial direction along the support shaft, the air in the dust boot on the compressed side flows through the air communication path into the other dust boot. become. therefore,
The pressure in the dust boots on both sides is always kept equal, and the generation of sliding resistance due to the pressure difference is prevented.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. The figures show an embodiment of a sliding rubber bush according to the present invention, with FIG. 1 being a longitudinal sectional view thereof, and FIG. 2 being an enlarged view of the main parts thereof. Moreover, FIG. 3 is a cross-sectional view of the inner cylinder portion of the rubber bush, FIG. 4 is an enlarged view of the main part, and FIG. 5 is an explanatory view showing the procedure for attaching the sliding collar to the inner cylinder. 6 and 7 are a plan view and a side view showing a rear suspension of an automobile in which the rubber bush is used.

As is clear from FIGS. 6 and 7, this rear suspension 1 includes a trailing arm 2 arranged in the longitudinal direction of the vehicle body (the left side in the figure is the front of the vehicle body). At the rear end of the trailing arm 2 is a rear axle 3.
is attached, and a rear wheel 4 is rotatably supported by the axle 3. That is, the rear end portion of the trailing arm 2 serves as a wheel support portion. A sliding rubber bush 5 as described later is attached to the front end side of the trailing arm 2. The rubber bush 5 is arranged so that its axis extends in the left-right direction of the vehicle body, and is attached to a support shaft 7 fixed to the vehicle body frame 6 in the left-right direction. In this way, the trailing arm 2 is connected at its front end side to the vehicle body via the rubber bush 5, and is supported so as to be swingable in the vertical direction. The wheels 4 are made to move up and down by the vertical swinging.

The front end side of the trailing arm 2 is configured to extend further forward than the mounting portion of the rubber bush 5, that is, the vehicle body side connecting portion 8. One end of a first lateral link 10, which is disposed substantially in the left-right direction of the vehicle body, is swingably connected to the front end of the extension portion 9 via a rubber bush 11. The other end of the first lateral link 10 is swingably connected to a front vehicle body cross member 13 via a rubber bush 12. The lateral link 10 is inclined slightly upward and rearward toward the outside of the vehicle body when the wheel 4 is in a neutral state with no vertical force acting on it.

Further, at the rear end of the trailing arm 2, an arm portion 14 extending upward and slightly diagonally forward, and a protruding portion 15 slightly protruding downward are provided. One end of a relatively short second lateral link 16 arranged in the left-right direction of the vehicle body is swingably connected to the upper end of the arm portion 14 via a rubber bush 17. The other end of the second lateral link 16 is swingably connected to the vehicle body frame 6 via a rubber bush 18. Similarly, the downward protrusion 15 at the rear end of the trailing arm 2
, there is a third lateral link 1 arranged in the left-right direction of the vehicle body.
One end of 9 is swingably connected via a rubber bush 20. The third lateral link 19 is relatively long, and the other end is swingably connected to a rear vehicle body cross member 22 via a rubber bush 21. The second lateral link 16 is substantially horizontal when in the neutral state. On the other hand, the third lateral link 19 is
In the neutral state, it is tilted slightly downward and forward toward the outside of the vehicle body.

In this way, the trailing arm 2 has three lateral links 10 disposed in the left-right direction of the vehicle body.
, 16, 19 to the vehicle body side, and the lateral posture of the trailing arm 2, and thus the camber and toe angle of the wheel 4, are controlled by these. Rubber bushes 11, 17 that connect the lateral links 10, 16, 19 to the trailing arm 2 side
, 20 and rubber bushes 12, 18, connected to the vehicle body side.
21 is the same as the conventional one.

A lower end of a damper 23 is rotatably connected to a portion of the third lateral link 19 near the trailing arm 2 via a horizontal axis. The upper end of the damper 23 is rotatably connected to a wheel house 24 of the vehicle body. A suspension spring 25 is provided between the lower part of the damper 23 and the wheel house 24, so that the wheel 4 is elastically supported in the vertical direction.

As shown in FIG. 1, a rubber bush 5 is provided at the vehicle body side connecting portion 8 of the trailing arm 2.
is formed by an inner cylinder 26, an outer cylinder 27 arranged concentrically at a distance on the outer circumferential side of the inner cylinder 26, and a rubber-like elastic body 28 arranged between the inner cylinder 26 and the outer cylinder 27. It is configured. The rubber-like elastic body 28 is ring-shaped with gaps 29 provided on both sides in the diametrical direction, and its inner and outer peripheral surfaces are vulcanized and bonded to the inner cylinder 26 and outer cylinder 27, respectively.
Thereby, the inner and outer cylinders 26 and 27 are connected to each other. The rubber bush 5 has its outer cylinder 27
It is fixed to the trailing arm 2 by press-fitting it into an opening provided in the vehicle body side connecting portion 8 of the trailing arm 2. In that case, as shown in FIG. 7, the rubber-like elastic body 28 is attached to the trailing arm 2 so that the gap 29 is located on the front and rear sides of the vehicle body, so that the rubber bush 5 is moved in the front and rear direction of the vehicle body. is easily deformed.

The inner peripheral surface of the inner cylinder 26 of the rubber bush 5 has
Sliding collar 3 made of bearing material with a small coefficient of friction
0 is attached. The collar 30 is slidably fitted onto the outer periphery of the support shaft 7 fixed to the vehicle body. The support shaft 7 is sufficiently longer than the inner cylinder 26. In this way, the rubber bush 5 is configured such that its inner cylinder 26 is slidable relative to the support shaft 7 in the axial direction and rotational direction. That is,
The rubber bush 5 is a sliding rubber bush.

The inner cylinder 26 of the rubber bush 5 is configured to protrude outward in the axial direction from both side surfaces of the rubber-like elastic body 28. Attachment rings 31, 31 each having a channel-shaped cross section with an open outer circumferential side are press-fitted onto the outer circumferential surfaces of the protrusions at both ends. The mounting ring 31 is a rubber-like elastic body 2
8, thereby creating a seal between them. One end of a cylindrical dust boot 32 made of an airtight and flexible material such as thin rubber is fitted into the outer peripheral groove of the attachment ring 31. and,
It is tightened from its outer circumferential side by a circlip 33. In this way, one end of the dust boot 32 is sealed with respect to the mounting ring 31, and is locked and fixed in a state where movement in the axial direction is restricted. On the other hand, a mandrel 34 is embedded in the opening periphery of the other end of the dust boot 32, and by press-fitting its end into the small diameter end of the support shaft 7, the other end of the dust boot 32 is supported. It is adapted to be closely fixed to the outer peripheral surface of the shaft 7. In this way, both ends of the dust boot 32 are airtightly attached to the outer circumferential surface of the end portion of the inner tube 26 and the outer circumferential surface of the support shaft 7, respectively. By providing such dust boots 32 on both sides of the rubber bush 5, the sliding portion between the inner circumferential surface of the inner cylinder 26 and the outer circumferential surface of the support shaft 7 is airtightly shielded from the outside. It has become.

As shown in FIGS. 2 and 3, a plurality of grooves 35 extending in the axial direction are formed on the inner peripheral surface of the inner cylinder 26 of the rubber bushing 5 at equal intervals in the circumferential direction. There is. The sliding collar 30 attached to the inner peripheral surface has a constant wall thickness and is shaped to follow the grooved inner peripheral surface of the inner cylinder 26. Therefore, a similar groove 36 is also formed on the inner peripheral surface of the collar 30. On the other hand, sliding collar 3
The inner diameter of the general portion of 0 is approximately equal to the outer diameter of the support shaft 7. That is, the collar 30 is designed so that no clearance occurs between it and the support shaft 7 in the general portion. In this way, the sliding collar 30 is fitted onto the support shaft 7 without any play. The groove 36 of the collar 30 allows the support shaft 7 to
An air communication passage 37 extending in the axial direction is formed between the
dust boots 32 provided on both sides of the rubber bush 5;
The spaces within 32 communicate with each other via the air communication passage 37.

[0023] Also, in this way, the groove 36 of the sliding collar 30
By fitting this portion into the groove 35 of the inner cylinder 26, rotation of the collar 30 relative to the inner cylinder 26 is restricted. Further, flange portions 38, 38 are formed at both ends of the sliding collar 30 in the axial direction, and the flange portions 38, 38 engage with both end surfaces of the inner cylinder 26, respectively, so that the inner cylinder 26 of the collar 30 Movement in the axial direction is restricted.

This sliding collar 30 is made into a cylindrical shape by abutting opposite edges of a thin flat plate-like member made of a low-friction material, and is formed along the inner circumferential surface of the inner cylinder 26, as described above. It is formed into a shape. In that case, as shown in FIG. 4, the abutting portion 39 is positioned within the groove 35 of the inner cylinder 26. As a material used for such a sliding collar 30, there is a material called "Hiplast" (trade name) manufactured by Oiles Industries, Ltd., for example. ``Hyplast'' is a composite material of gunmetal mesh and filled polytetrafluoroethylene resin, which has an extremely low coefficient of friction, is wear resistant, and is thin, flexible, and has excellent moldability. .

When assembling such a sliding collar 30 to the inner cylinder 26 of the rubber bush 5, first, as shown in FIG.
As shown in , a flat member made of a low-friction material is made into a cylindrical shape by bringing together its opposing edges. Then, one axial end portion of the cylindrical member 40 thus formed is bent at a right angle to form one flange portion 38. Next, as shown in FIG. 5(B), the cylindrical member 40 is inserted into the inner cylinder 26, and the flange portion 38 is brought into contact with one end surface of the inner cylinder 26. Then, the other end side of the cylindrical member 40 is caulked,
The other flange portion 38 is formed. In that case, Fig. 5 (C
), the mating parts of the flat plate members are slightly overlapped, and the mating parts are connected to the inner cylinder 2.
so that it is positioned on the groove 35 of No. 6. Next, the cylindrical member 40 is pressed against the inner circumferential surface of the inner cylinder 26 using a mold, and the groove 36 is formed by pushing it into the groove 35 of the inner cylinder 26 as shown in FIG. 5(D). do. In this way,
A sliding collar 30 having a desired shape is formed, and the collar 30 is fixed to the inner peripheral surface of the inner cylinder 26.

Next, the operation of the sliding rubber bushing 5 constructed as described above will be explained. In the automobile rear suspension 1 using this rubber bush 5,
When a vertical force is applied to the wheel 4 and the wheel 4 moves up and down, the trailing arm 2 supporting the wheel 4 at its rear end moves up and down around the vehicle body side connecting portion 8 at its front end. swing in the direction. At this time, the vehicle body side connecting portion 8
The rubber bush 5 is provided with an outer cylinder 27 fixed to the trailing arm 2, and an inner cylinder 26 connected to the outer cylinder 27 via a rubber-like elastic body 28, which is attached to a support shaft on the vehicle body side. 7, the entire body rotates around the support shaft 7 as the trailing arm 2 swings. Therefore, no load acts on the rubber-like elastic body 28. The vertical movement of the wheel 4 is damped by the damper 23 and the suspension spring 25.

Further, when the wheel 4 moves up and down in this manner, the camber and toe angle of the wheel 4 are controlled by the three lateral links 10, 16, and 19. That is,
When the wheel 4 moves up and down, the trailing arm 2 swings up and down as described above, so the three lateral links 10, 16, 19 that connect the trailing arm 2 and the vehicle body in the left and right direction , swings vertically around rubber bushes 12, 18, and 21, which are connection parts on the vehicle body side. By the swinging, the trailing arm 2 is moved in the left-right direction of the vehicle body. In that case, since the lengths, inclinations, etc. of those lateral links 10, 16, 19 are different, the amount of displacement of the trailing arm 2 in the left-right direction of the vehicle body is determined by the portion to which these lateral links 10, 16, 19 are connected. Each will be different depending on the Therefore, when the first and third lateral links 10 and 19 swing, the positions of the front and rear ends of the trailing arm 2 to which they are connected in the left-right direction of the vehicle body change, and the positions of the trailing arm 2 in the front-rear direction of the vehicle body change. The slope of is determined. In addition, due to the swinging of the second and third lateral links 16 and 19, the positions of the upper and lower portions of the trailing arm 2 in the left-right direction of the vehicle body change, and the inclination of the vehicle body in the vertical direction is determined. In this way, the three lateral links 10, 16
, 19 control the inclination of the trailing arm 2 during bump rebound. The wheels 4 also tilt accordingly. That is, the camber and toe angle of the wheels 4 are controlled. Therefore, by appropriately selecting the length and inclination of these three lateral links 10, 16, 19, or the position of their connecting portions, the attitude of the wheel 4 during bump rebound can be set optimally. Ride comfort and maneuverability can be improved.

As described above, in this rear suspension 1, when the wheels 4 move up and down, the entire trailing arm 2 is displaced in the left-right direction of the vehicle body. Moreover, the first
Since the lateral link 10 is disposed near the vehicle body-side connecting portion 8 that supports the trailing arm 2, the vehicle body-side connecting portion 8 also tends to displace in the left-right direction of the vehicle body. In this case, in this suspension 1, the rubber bush 5 provided on the vehicle body-side connecting portion 8 is slidable in the axial direction, that is, in the left-right direction of the vehicle body, with respect to the support shaft 7 fixed to the vehicle body. Therefore, the displacement at that time is allowed by the sliding movement. Therefore, the trailing arm 2 is displaced without elastically deforming the rubber-like elastic body 28 of the rubber bush 5, and the attitude control of the wheel 4 is performed smoothly, ensuring good ride comfort and maneuverability at all times. Ru.

When the rubber bush 5 slides in the axial direction in this way, the dust boots 3 provided on both sides of the rubber bush 5
2 and 32, one of which is compressed and the other is tensioned. Therefore, the pressure within one dust boot 32 will increase. However, in the case of this rubber bush 5, since the air in the dust boot 32 flows into the other dust boot 32 through the air communication passage 37, the pressure increase is suppressed. Therefore, the pressure is prevented from interfering with the movement of the rubber bush 5 in the axial direction, that is, with the displacement of the trailing arm 2 in the left-right direction of the vehicle body.

Further, in the case of this rubber bush 5, the sliding collar 30 attached to the inner peripheral surface of the inner cylinder 26 is attached to the support shaft 7.
When the inner cylinder 26 rotates or slides in the axial direction with respect to the support shaft 7,
The sliding collar 30 attempts to move relative to the inner cylinder 26. However, since the collar 30 is fitted into a groove 35 formed on the inner peripheral surface of the inner cylinder 26, its relative rotation is restricted. Further, since the flanges 38, 38 formed at both ends of the sliding collar 30 engage with both end surfaces of the inner cylinder 26, the relative displacement of the collar 30 with respect to the inner cylinder 26 in the axial direction is also restricted. . therefore,
The collar 30 and the inner cylinder 26 do not slide relative to each other, and wear is prevented from occurring therebetween. In particular, when the above-mentioned "Hyplast" is used for the sliding collar 30, the wear resistance of the back surface is relatively low, so wear between the collar 30 and the inner cylinder 26 is prevented in this way. This has a significant effect on increasing its durability.

Furthermore, in the case of the rubber bushing 5 using the sliding collar 30 formed into a cylindrical shape by abutting both ends of a flat member as described above, the abutting portion 39 contacts the outer circumferential surface of the support shaft 7. If so, when the rubber bush 5 rotates relative to the support shaft 7, the collar 30 may peel off from the abutting portion 39 due to friction therebetween. However, in the case of this rubber bush 5, the abutting portion 39 is disposed within the groove 35 of the inner cylinder 26 and is prevented from coming into sliding contact with the support shaft 7, so such peeling is also prevented. Ru.

As described above, according to this sliding rubber bush 5, the dust boots 32, which are attached to both sides of the rubber bush 5,
32 hermetically seals the sliding part between the support shaft 7 from the outside, protects the sliding part, and also reduces sliding resistance by making the spaces inside the dust boots 32 on both sides communicate with each other. Since an increase in the amount of friction is prevented, smooth sliding performance can always be obtained. In addition, sliding on the support shaft 7 is ensured by the low-friction sliding collar 30 attached to the inner peripheral surface of the inner cylinder 26, so that the rubber bush 5 can slide smoothly on the support shaft 7. However, by eliminating the clearance between the rubber bush 5 and the support shaft 7, it is possible to suppress rattling therebetween. Moreover, since the sliding collar 30 is prevented from sliding against or peeling off from the inner cylinder 26, its durability can be improved.

In the above embodiment, the air communication passage 37 is formed between the rubber bush 5 and the support shaft 7, but the air communication passage 37 extends from the inner cylinder 26 of the rubber bush 5 in the axial direction. It can also be formed as a through hole that penetrates through. Further, the air communication path can also be provided within the support shaft 7. To do this, for example, a through hole extending in the axial direction is provided in the support shaft 7, both ends of which are sealed, and a communication hole is bored that reaches the outer peripheral surface of the support shaft 7 from the through hole, and the dust boots 32 on both sides, What is necessary is to make the spaces within 32 communicate with each other. However, in that case, the opening on the outer peripheral surface of the support shaft 7 of the communication hole is always
Since it must be located within 2, setting the position becomes difficult. One end of the dust boot 32 does not have to be attached to the end of the inner tube 26 as in the above embodiment, but is instead attached to the outer tube 27 or the rubber-like elastic body 28 in an airtight manner. Good too. In short, it is sufficient that the space between the inner cylinder 26 and the outer circumferential surface of the support shaft 7 is airtightly sealed. Further, in the above embodiment, the rubber bush 5 used in the rear suspension 1 of an automobile was described, but the present invention is not limited thereto.
The present invention can be similarly applied to rubber bushings that are required to reduce resistance in the axial direction or rotational direction.

[0034]

As is clear from the above description, according to the present invention, the spaces within the pair of dust boots provided on both sides of the rubber bushing are made to communicate with each other, so that the support shaft can be controlled by the dust boots. The rubber bush can be slid smoothly on the support shaft while maintaining an airtight seal between the rubber bush and the support shaft. Therefore, it is possible to provide a sliding rubber bushing with low sliding resistance. In that case, if a sliding collar is attached to the inner circumferential surface of the inner cylinder of the rubber bush and the collar ensures sliding, the strength is provided by the inner cylinder, so the sliding collar has a sufficiently low friction. The inner cylinder can be made to slide smoothly on the support shaft. Moreover, by bringing the collar into sliding contact with the outer circumferential surface of the support shaft, it is possible to eliminate the clearance therebetween and prevent rattling. By providing a groove extending in the axial direction on the inner circumferential surface of the inner cylinder of the rubber bushing and shaping the sliding collar to follow the grooved inner circumferential surface, an air communication path is created that communicates between the pair of dust boots. Can be easily formed. Moreover, since the relative rotation between the sliding collar and the inner cylinder is thereby restricted, wear is prevented from occurring during this period, and durability can be improved. Furthermore, if the sliding collar is formed by abutting both ends of a flat plate-shaped low-friction member to form a cylindrical shape, the sliding collar can be obtained at low cost and can be easily attached to the inner cylinder. Therefore, the manufacturing cost can be reduced. In that case, if the abutting portion is located within the groove of the inner cylinder, it is possible to prevent the sliding collar from peeling off from the inner cylinder.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a sliding rubber bush according to the present invention.

FIG. 2 is an enlarged sectional view of essential parts of the rubber bush.

FIG. 3 is a cross-sectional view of the rubber bushing along line III-III in FIG. 2;

FIG. 4 is an enlarged view of a portion indicated by arrow IV in FIG. 3;

FIG. 5 is an explanatory diagram showing a procedure for attaching a sliding collar to the inner cylinder of the rubber bush.

FIG. 6 is a plan view showing a rear suspension of an automobile in which the rubber bush is used.

FIG. 7 is a side view of the rear suspension.

[Explanation of symbols]

1 Rear suspension 2 Trailing arm 5　Sliding rubber bushing 7 Support shaft 26 Inner cylinder 27 Outer cylinder 28 Rubber-like elastic body 30 Sliding collar 32 Dust boots 35 Inner cylinder groove 36 Sliding collar groove 37 Air communication passage 39 Butt part

Claims (3)

[Claims] Claim 1: An inner cylinder rotatably fitted to the outer periphery of a support shaft and slidable in the axial direction, and an outer cylinder arranged concentrically at a distance on the outer periphery of the inner cylinder. , a rubber-like elastic body disposed between the inner cylinder and the outer cylinder, and a rubber-like elastic body disposed between the inner cylinder and the outer peripheral surface of the support shaft; A sliding type rubber bushing, characterized in that a rubber bushing is provided with a dust boot for sealing a sliding part; an air communication path is formed for communicating spaces within the pair of dust boots with each other. 2. A groove extending in the axial direction is formed on the inner circumferential surface of the inner cylinder, and a sliding collar having a shape along the grooved inner circumferential surface of the inner cylinder is attached, and the sliding collar is attached to the inner circumferential surface of the inner cylinder. the air communication path is constituted by a groove in the collar;
A sliding rubber bush according to claim 1. 3. The sliding collar is formed into a cylindrical shape by abutting both end edges of a flat plate member,
3. The sliding rubber bushing according to claim 2, wherein the abutting portion is located within a groove in the inner circumferential surface of the inner cylinder.