JP7091698B2 - Bush - Google Patents

Description

The present disclosure relates to bushes, and more particularly to bushes used in cab mount mechanisms and the like for cab-over type vehicles.

Generally, a cab-over type vehicle such as a truck is provided with a cab mount mechanism that supports the cab so as to be tiltable with respect to the chassis frame. The cab mount mechanism includes a plurality of arms, brackets, and the like linked to each other, and a bush is interposed in these connecting portions.

As an example of this type of bush, for example, Patent Documents 1 and 2 include a support pin fixed to a connecting body and a cylindrical cylinder through which the support pin is inserted and fixed to the connected body. A structure is disclosed in which the outer peripheral surface of the support pin and the inner peripheral surface of the cylinder are in sliding contact with each other to enable smooth relative rotation between the connected body and the connected body.

Japanese Unexamined Patent Publication No. 2006-76410 Japanese Unexamined Patent Publication No. 2013-47559

By the way, in the structures disclosed in Patent Documents 1 and 2, the axial end portion of the gap between the support pin and the cylinder is exposed to the outside air. Therefore, mud, water, dust, etc. (hereinafter referred to as foreign matter) may invade from the end portion. When such a foreign substance is mixed with the grease in the void, an abnormal noise is generated when the connecting body and the connected body rotate relative to each other, or the grease is pushed out from the void by the foreign substance and leaks. There are challenges.

Further, in the structure disclosed in Patent Document 2, a plurality of protrusions provided at predetermined intervals in the circumferential direction at the axial end portion of the tubular body are in constant contact with the connecting body. Therefore, when the cylinder body rotates relative to the support pin, each protrusion may be in sliding contact with the connecting body and may be worn.

An object of the present disclosure technique is to effectively prevent foreign matter from entering between a support pin (shaft) and a cylinder.

The technique of the present disclosure is a bush that connects a connecting body and a connected body so as to be relatively rotatable, and is fixed to the connecting body and has a diameter expanded to a shaft portion and one end portion in the axial direction of the shaft portion. A shaft body having a flange portion provided therein and the shaft portion are rotatably inserted into the cylinder while being fixed to the connected body, and at least a part of one end surface thereof is the flange portion. A cylinder that can be slidably contacted with the inner side surface on the shaft portion side, and one end surface of the cylinder portion that is radially outer than the sliding contact portion with the inner side surface of the flange portion in the axial direction. It is characterized in that it is provided so as to project in a cylindrical shape, and has a tubular protrusion portion whose inner tubular surface faces the sliding contact portion.

Further, it is preferable that the protruding end of the tubular protrusion portion is located axially inside the outer surface of the flange portion.

Further, it is preferable to further provide an annular side washer attached to the other end of the shaft portion in the axial direction opposite to the flange portion.

Further, a concave groove provided in the circumferential direction on the other end of the outer peripheral surface of the shaft portion in the axial direction and a ridge provided on the inner peripheral surface of the side washer and fit into the concave groove are further provided. Is preferable.

Further, a cylindrical sleeve and a pair of seal rings facing each other across the sleeve are interposed in the gap between the outer peripheral surface of the shaft portion and the inner peripheral surface of the cylinder, and the pair of seal rings. It is preferable that the gap between them is filled with grease.

Further, the cylinder includes an inner cylinder portion made of a metal material, an inner cylinder portion made of an elastic material, and an outer cylinder portion made of a metal material in order from the inner side in the radial direction. It is preferable that the shaped protrusion portion is integrally formed with the middle cylinder portion.

According to the technique of the present disclosure, it is possible to effectively prevent foreign matter from entering between the support pin (shaft) and the cylinder.

It is a side view which shows typically an example of the cab mount mechanism to which the bush which concerns on this embodiment is applied. It is a schematic cross-sectional view which shows the bush which concerns on this embodiment, (A) is an assembly drawing, (B) is an exploded view, respectively. It is a schematic sectional drawing which shows the bush which concerns on other embodiment.

Hereinafter, the bush according to the present embodiment will be described with reference to the attached drawings. The same parts are designated by the same reference numerals, and their names and functions are also the same. Therefore, detailed explanations about them will not be repeated.

FIG. 1 is a side view schematically showing an example of a cab mount mechanism 50 to which a bush 10 according to the present embodiment is applied. As shown in the figure, the cab mount mechanism 50 includes a hinge bracket 2 fixed to a chassis frame 1 extending in the front-rear direction of the vehicle, an upper bracket 5 fixed to a cab member 6 constituting a lower portion of the cab C, and these. It includes a link lever 3 rotatably hinged to each of the brackets 2 and 5, an air spring 7 interposed between the link lever 3 and the upper bracket 5, and a shock absorber 8.

A bush 10 is interposed between the link lever 3 and the hinge bracket 2 and between the upper bracket 5 and the link lever 3, respectively. Specifically, each bush 10 includes a support pin 11 and a substantially cylindrical cylindrical body 12 into which the support pin 11 is inserted so as to be relatively rotatable.

Of these bushes 10, the bush 10 on the front side of the vehicle body has a support pin 11 fixed to the link lever 3 and a tubular body 12 fitted and fixed to the hinge bracket 2. That is, the hinge bracket 2 and the link lever 3 are hinged and connected so as to be relatively rotatable via the tubular body 12 with the support pin 11 of the bush 10 on the front side of the vehicle body as a fulcrum. Further, in the bush 10 on the rear side of the vehicle body, the support pin 11 is fixed to the upper bracket 5, and the tubular body 12 is fitted and fixed to the link lever 3. That is, the link lever 3 and the upper bracket 5 are hinged and connected so as to be relatively rotatable via the tubular body 12 with the support pin 11 of the bush 10 on the rear side of the vehicle body as a fulcrum.

In the cab mount mechanism 50 configured as described above, when the cab C is tilted (forward tilted), the link lever 3 rotates counterclockwise in the figure with the pin member 11 of the bush 10 on the front side as a fulcrum. The cab C is designed to lean forward. Further, when the cab C is not tilted, such as when the vehicle is running, the link lever 3 and the brackets 2 and 5 swing around the pin member 11 of each of the front and rear bushes 10 as a fulcrum, and follow these swings. By expanding and contracting the air spring 7 and / or the shock absorber 8, the impact and vibration transmitted from the chassis frame 1 to the cab C are effectively damped.

Next, the details of the bush 10 according to the present embodiment will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing the bush 10 according to the present embodiment. As shown in the figure, the bush 10 includes a support pin 11, a cylinder 12, a sleeve 16, an O-ring 17, and a side washer 20.

The support pin 11 is formed of, for example, a metal material in a substantially cylindrical shape, and integrally has a shaft portion 11A and a flange portion 11B formed by expanding the diameter toward one end side in the axial direction of the shaft portion 11A. There is. The axial length of the shaft portion 11A is formed to be longer than the tubular axial length of the tubular body 12 so that the other end portion in the axial direction protrudes from the end surface of the tubular body 12. The outer diameter of the flange portion 11B is formed to be larger than the inner diameter of the inner cylinder portion 13 so that the inner side surface 11C thereof and the cylinder end surface 13A of the inner cylinder portion 13 described later can come into contact with each other. Further, an annular concave groove 19 is recessed over the entire circumference in the circumferential direction on the outer peripheral surface of the other end of the shaft portion 11A in the tubular axial direction. The cross-sectional shape of the concave groove 19 is preferably formed so as to be smoothly recessed in a semicircular shape inward in the radial direction. The concave groove 19 is fitted with the ridge 23 of the side washer 20, which will be described later.

The cylinder body 12 has a substantially cylindrical shape as a whole, and includes an inner cylinder portion 13, an inner cylinder portion 14, and an outer cylinder portion 15 in order from the inner side in the radial direction. The inner cylinder portion 13, the middle cylinder portion 14, and the outer cylinder portion 15 are preferably fixed to each other so as to be integrally rotatable by vulcanization adhesion or the like.

The inner cylinder portion 13 is formed of, for example, a metal material or the like into a substantially cylindrical shape. The inner diameter of the inner cylinder portion 13 is formed to be larger than the outer diameter of the shaft portion 11A of the support pin 11 and smaller than the outer diameter of the flange portion 11B. That is, between the inner cylinder portion 13 and the support pin 11, the inner peripheral surface 13C of the inner cylinder portion 13, the outer peripheral surface 11E of the shaft portion 11A, the inner side surface 11C of the flange portion 11B, and the side washer 20 described later. A predetermined void S1 defined by the inner side surface 21A of the above is formed. A sleeve 16 and an O-ring 17, which will be described later, are interposed in the gap S1.

Further, the length of the inner cylinder portion 13 in the cylinder axis direction is formed to be shorter than the length of the shaft portion 11A in the cylinder axis direction so that the inner peripheral surface thereof does not overlap with the opening of the concave groove 19. Specifically, the length of the inner cylinder portion 13 in the cylinder axis direction is preferably such that the cylinder end surface 13A and the inner side surface 11C of the flange portion 11B can be brought into contact with each other, and the cylinder end surface 13B is the side washer 20. It is formed to be slightly shorter than the value obtained by subtracting the axial thickness of the side washer 20 from the tubular axial length of the shaft portion 11A so as to face (close) to the inner side surface 21A with a slight gap. .. In the present embodiment, the outer diameter of the inner cylinder portion 13 is formed to be larger than the outer diameter of the flange portion 11B, and the cylinder end surface 13A of the inner cylinder portion 13 partially contacts the inner side surface 11C of the flange portion 11B. As a result, these metal contacts are effectively reduced.

The middle cylinder portion 14 is formed in a substantially cylindrical shape, for example, with an elastic material, and has a main body portion 14A and a cylindrical protrusion portion 14B integrally. The inner diameter of the cylinder of the main body 14A is formed to be substantially the same as the outer diameter of the inner cylinder 13, and the main body 14A is externally fitted to the inner cylinder 13 to form the middle cylinder 14 and the inner cylinder. 13 is configured to be integrally rotatable. A cylindrical protrusion 14B is provided on one end surface (cylindrical end surface) 14C of the main body portion 14A in the tubular axial direction, and a semicircular arc shape is recessed in the other end surface 14D of the main body portion 14A in the tubular axial direction. A curved portion is formed.

The cylindrical protrusion 14B is formed on the cylinder end surface 14C of the middle cylinder portion 14 so as to project substantially in a cylindrical shape in the cylinder axis direction over the entire length in the circumferential direction. The protrusion length of the cylindrical protrusion 14B is such that the inner cylinder surface 14E faces the contact portion X between the inner cylinder portion 13 and the flange portion 11B at a distance outward in the radial direction, and the protrusion end 14F is opposed to the contact portion X. , Is formed so as to be located slightly inward in the axial direction with respect to the outer end surface 11D of the flange portion 11B. That is, in the radial view of the cylinder 12, the contact portion X between the inner cylinder portion 13 and the flange portion 11B is configured to be shielded by the cylindrical protrusion portion 14B. As a result, the arrival of the contact portion X such as the splash is blocked, and it becomes possible to effectively prevent foreign matter from entering the gap S1 between the support pin 11 and the inner cylinder portion 13. .. Further, by locating the protruding end 14F of the cylindrical protrusion 14B slightly inside the outer end surface 11D of the flange portion 11B, at least under normal conditions, the cylindrical protrusion 14B and the connecting body (link lever shown in FIG. 1) are connected. Contact with 3 or the upper bracket 5) is effectively prevented.

The outer cylinder portion 15 is formed of, for example, a metal material or the like into a substantially cylindrical shape. The inner diameter of the outer cylinder portion 15 is formed to be substantially the same as the outer diameter of the cylinder portion 14A of the main body portion 14A of the middle cylinder portion 14, and the outer cylinder portion 15 is externally fitted to the main body portion 14A to form an outer cylinder portion. The 15 and the middle cylinder portion 14 are configured to be integrally rotatable. Further, the length of the outer cylinder portion 15 in the cylinder axis direction is substantially the same as the length of the inner cylinder portion 13 in the cylinder axis direction, and is formed to be longer than the length of the main body portion 14A of the middle cylinder portion 14 in the cylinder axis direction. That is, the inner peripheral surface on one end side of the outer cylinder portion 15, the cylinder end surface 14C of the middle cylinder portion 14, and the cylinder outer surface of the cylindrical protrusion portion 14B are on the side of the connecting body (link lever 3 or upper bracket 5 shown in FIG. 1). A predetermined space S2 opened to the outside is defined, and the inner peripheral surface on the other end side of the outer cylinder portion 15, the cylinder end surface 14D of the middle cylinder portion 14, and the outer peripheral surface on the other end side in the cylinder axis direction of the inner cylinder portion 13. A predetermined closed space S3 is defined by the inner side surface 22A of the side washer 20, which will be described later.

The sleeve 16 is formed of, for example, a resin material or the like into a substantially cylindrical shape. The inner diameter of the sleeve 16 is slightly larger than the outer diameter of the cylinder of the support pin 11, and the outer diameter of the sleeve 16 is slightly smaller than the inner diameter of the inner cylinder 13. That is, by inserting the sleeve 16 into the gap between the outer peripheral surface of the support pin 11 and the inner peripheral surface of the inner cylinder portion 13, the outer peripheral surface of the support pin 11 and the inner peripheral surface of the inner cylinder portion 13 are sleeved. It is designed to be supported by sliding contact with 16. Further, the length of the sleeve 16 in the tubular axis direction is formed to be shorter than the length of the inner tubular portion 13 in the tubular axis direction, and a pair of O-rings 17 are fitted in the gaps adjacent to both ends of the sleeve 16. It has been.

The O-ring 17 is formed of, for example, an elastic material in a substantially ring shape. The O-ring 17 is attached to the outer peripheral surface of the support pin 11 and the inner peripheral surface of the inner cylinder portion 13 in a pressure contact state in a gap adjacent to both ends of the sleeve 16. The gap between the pair of O-rings 17 facing each other across the sleeve 16 is filled with grease that facilitates the relative rotation between the support pin 11 and the inner cylinder portion 13.

The inner diameter of the side washer 20 is substantially the same as the outer diameter of the shaft portion 11A of the support pin 11, and the outer diameter thereof is formed to be larger than the outer diameter of the outer cylinder portion 15, which is a substantially annular shape as a whole. It is (disk-shaped). Specifically, the side washer 20 includes an outer annulus portion 21 and an inner annulus portion 22.

The outer annulus portion 21 is formed of, for example, an elastic body material, and has a function of effectively absorbing the axial displacement (impact) of the tubular body 12. The inner diameter of the outer annulus portion 21 is formed to be substantially the same as the outer diameter of the shaft portion 11A of the support pin 11. On the outer surface of the outer annular portion 21, a pair of annular grooves 24 for holding grease are recessed between the connecting body (link lever 3 or upper bracket 5 shown in FIG. 1). Further, a recess 25 for fitting the inner ring portion 22 is recessed in the inner portion of the outer ring portion 21. Further, on the inner peripheral portion of the outer annular portion 21, an annular ridge 23 projecting inward in the radial direction is convexly provided over the entire circumference in the circumferential direction. The cross-sectional shape of the ridge 23 is preferably formed so as to smoothly project inward in the radial direction in a semicircular shape. By fitting the ridge 23 into the concave groove 19, the side washer 20 can be temporarily held (pre-assembled) with respect to the support pin 11.

The inner annulus portion 22 is made of, for example, a metal material. The inner diameter of the inner ring portion 22 is larger than the inner diameter of the outer ring portion 21, and the outer diameter of the inner ring portion 22 is smaller than the outer diameter of the outer ring portion 21. Further, the axial length of the inner annulus portion 22 is about half the axial length of the radial inner end of the outer annulus portion 21. By fitting the inner annulus portion 22 into the recess 25 of the outer annulus portion 21, the inner annulus portion 22 and the outer annulus portion 21 are configured to be integrated.

According to the present embodiment configured as described above, the inner cylinder surface 14E of the cylindrical protrusion portion 14B integrally formed with the middle cylinder portion 14 with respect to the contact portion X between the inner cylinder portion 13 and the flange portion 11B. They are arranged so as to face each other at a distance from the outside in the radial direction. That is, in the radial view of the cylinder 12, the contact portion X between the inner cylinder portion 13 and the flange portion 11B and one end of the gap S1 are configured to be shielded over the entire circumference by the cylindrical protrusion portion 14B. There is.

Further, when the ridge 23 is fitted into the concave groove 19 and the side washer 20 is assembled to the other end of the shaft portion 11A of the support pin 11 in the axial direction, the inner side surface 21A on the inner side in the radial direction of the outer annulus portion 21 and The inner side surface 22A on the inner side of the inner ring portion 22 in the radial direction is configured to face each other with a slight gap while being close to the cylinder end surface 13B of the inner cylinder portion 13. That is, the inner side surfaces 21A and 22A of the side washer 20 shield the other end of the gap S1 between the support pin 11 and the inner cylinder portion 13.

This makes it possible to effectively prevent foreign matter from entering the gap S1 and further from mixing the foreign matter into the grease in the gap S1. Further, it is possible to effectively prevent the O-ring 17 (sealing material) from being worn by foreign matter mixed in the grease. Further, when the cab mount mechanism 50 is operating (particularly, rocking when the vehicle is running), an abnormal noise is generated due to the mixing of foreign matter, and further, the support pin 11 and the inner cylinder portion 13 due to the mixing of foreign matter are generated. It is possible to effectively prevent rust and the like.

Further, by locating the protruding end 14F of the cylindrical protrusion 14B slightly inside the outer end surface 11D of the flange portion 11B, the cylindrical protrusion 14B and the connecting body (link lever 3 or upper bracket 5) are under normal conditions. ) Is effectively prevented. As a result, even if the tubular body 12 rotates relative to the support pin 11, it is possible to effectively prevent the wear of the cylindrical protrusion 14B due to these sliding contacts.

Further, since the side washer 20 can be temporarily held to the shaft portion 11A of the support pin 11 by fitting the ridge 23 into the concave groove 19, work efficiency can be improved by pre-assembling these at the vehicle assembly site. Further, when the component is transported as a single component, it is possible to effectively prevent the side washer 20 from coming off the shaft portion 11A of the support pin 11 and being lost.

Further, since it is not necessary to attach a caulking ring for restricting the axial movement of the tubular body 12 to the support pin 11 or to perform caulking processing, the support pin 11 has a simple structure. It is possible to reduce the cost while effectively reducing the processing man-hours.

Further, by forming the cylindrical protrusion 14B integrally with the middle cylinder portion 14, it is possible to effectively prevent the cost increase due to the increase in the number of parts.

It should be noted that the present disclosure is not limited to the above-described embodiment, and can be appropriately modified and implemented without departing from the spirit of the present disclosure.

For example, as shown in FIG. 3, flange portions 11B are provided at both ends of the support pin 11, and the flange portion 11B on the opposite side of the cylindrical protrusion 14B is formed into an annular shape having a substantially L-shaped cross section using an elastic material or the like. The formed cover member 40 may be attached, and the cover member 40 may be configured to cover the other end of the gap S1 between the support pin 11 and the inner cylinder portion 13. In this case, the support pins 11 may be fitted into each other in a two-piece structure (two-divided structure) so that the tubular body 12 can be extrapolated to the shaft portion 11A of the support pins 11.

Further, the number of the cylindrical protrusions 14B is not limited to one, and a plurality of cylindrical protrusions 14B may be arranged in double or triple or more in the radial direction.

Further, the inner side surfaces 21A and 22A of the side washer 20 are described as facing the cylinder end surface 13B of the inner cylinder portion 13 with a slight gap, but the inner side surfaces 21A and 22A of the side washer 20 are the inner cylinder portions. It may be configured to be in contact with the cylinder end surface 13B of 13. Also in this case, the inner side surfaces 21A and 22A of the side washer 20 block the other end of the gap S1 between the support pin 11 and the inner cylinder portion 13, effectively allowing foreign matter to enter the gap S1. Can be prevented.

Further, although the application of the bush 10 has been described by taking the cab mount mechanism 50 as an example, it is widely applied to other mechanisms such as a suspension mechanism that supports the leaf spring on the chassis frame and the like so as to connect the connecting body to the connected body so as to be relatively rotatable. It is possible to apply.

1 Chassis frame 2 Hinge bracket 3 Link lever 5 Upper bracket 6 Cab member 7 Air spring 8 Shock absorber 10 Bush 11 Support pin 11A Shaft 11B Flange 12 Cylinder 13 Inner cylinder 14 Middle cylinder 14A Main body 14B Cylindrical protrusion 15 Outer cylinder 16 Sleeve 17 O-ring 19 Concave groove 20 Side washer 21 Outer annulus 22 Inner annulus 23 Convex 50 Cab mount mechanism

Claims (5)

A bush that rotatably connects the connected body and the connected body.
A shaft body fixed to the connecting body and having a shaft portion and a flange portion provided at one end in the axial direction of the shaft portion with an expanded diameter.
The shaft portion is rotatably inserted into the cylinder while being fixed to the connected body, and at least a part of one end surface thereof can be slidably contacted with the inner side surface of the flange portion on the shaft portion side. With the cylinder
Of the one end surface of the cylinder, the flange portion is provided so as to project axially from one end surface radially outside the sliding contact portion with the inner side surface of the flange portion, and the inner cylinder surface thereof is the flange . A cylindrical protrusion facing the flange portion in a state of being separated from the portion is provided.
The cylinder is made of a metal material in order from the inside in the radial direction, and the inner cylinder portion whose end surface is in contact with the inner side surface of the flange portion, the middle cylinder portion formed of an elastic material, and the metal material. It is provided with a formed outer cylinder portion, and the tubular protrusion portion is integrally formed with the middle cylinder portion.
A bush characterized in that the outer diameter of the inner cylinder portion is larger than the outer diameter of the flange portion. The bush according to claim 1, wherein the protruding end of the tubular protrusion is located axially inside the outer surface of the flange. The bush according to claim 1 or 2, further comprising an annular side washer attached to the other end of the shaft portion in the axial direction opposite to the flange portion. A claim further comprising a concave groove provided in the circumferential direction at the other end of the outer peripheral surface of the shaft portion in the axial direction, and a ridge provided on the inner peripheral surface of the side washer and fit into the concave groove. The bush according to 3. A cylindrical sleeve and a pair of seal rings facing each other across the sleeve are interposed in the gap between the outer peripheral surface of the shaft portion and the inner peripheral surface of the cylinder, and between the pair of seal rings. The bush according to any one of claims 1 to 4, wherein the voids are filled with grease.

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