JP2000249180A - Bushing for leaf spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bushing for leaf spring having good durability of its resilient body made of rubber against twisting through heightening of the pressure fitting rate of the resilient body and assuring easy mounting on a member as the mating party. SOLUTION: A first resilient part made of rubber vulcanized and adhered between one end in axial direction of an inner cylindrical metal fitting 11 and a position near the other end is furnished at one end in axial direction with a first thick wall portion 13 in a ring shape having an outside diameter greater than the inside diameter of an arm eye 40, and in other part with two intermediate thick wall portions in ring shape having such outside diameters adjoining each other in the axial direction as greater than the inside diameter of the arm eye 40. The intermediate thick wall portions vulcanized and adhered to the inner cylindrical metal fitting is fitted by pressure in a first outer cylindrical metal fitting 16 made from metal pipe having a small wall thickness so that a bushing 10 is formed. The bushing 10 is fitted by pressure from one-end opening of the arm eye 40 and inserted into the arm eye 40. The pressure fitting rate of the intermediate thick wall portions is made as high as 20% or more due to the pressure fitting in the first outer cylindrical metal fitting 16 and pressure fitting into the arm eye 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a leaf spring bush applied between a vehicle body and a leaf spring.

[0002]

2. Description of the Related Art Conventional leaf spring bushes are
For example, as shown in FIG. 5, it is constituted by a pair of bush members 1. As shown in FIG. 6, the bush member 1 includes an inner cylinder 2, which is a shaft, a rubber elastic body 3 fixed on the outer peripheral surface of the inner cylinder 2, and a rubber elastic body 3 fixed on the outer peripheral surface of the rubber elastic body 3. And a thin outer tube fitting 6. As shown in FIG. 7, the rubber elastic body 3 has a cylindrical shape fixed on the outer peripheral surface of the inner cylindrical fitting 2, and has an annular end thick part 4 protruding radially toward one end in the axial direction, An intermediate thick portion 5 is provided adjacent to the thick portion 4 and extending to the other end in the axial direction. Outer tube fitting 6
Has a cylindrical portion whose inner diameter is smaller than the outer diameter of the intermediate thick portion 5 of the rubber elastic body 3, and a flange portion protruding radially outward at one end of the cylindrical portion. The bush member 1 is formed by press-fitting the intermediate thick portion 5 of the rubber elastic body 3 into the outer tube fitting 6.

The pair of bush members 1 are press-fitted and inserted from both ends in the axial direction into arm eyes 9 of a leaf spring, which is a mating cylindrical member, from the other end side in the axial direction (the middle thick portion 5 side). , The middle thick part 5 is the inner cylindrical fitting 2
And the arm eye 9 in a state of being compressed and deformed in the radial direction. Here, in the press-fitting of the intermediate thick portion 5, a press-fitting rate lower than 20% is adopted in consideration of workability of press-fitting and the like. For the pair of bush members 1 inserted into the arm eye 9 in this manner, the bolt 8 is inserted into the shaft hole 2a from the end of one of the inner cylindrical fittings 2 through the annular washer 7a.
a, and a bolt 8 protruding from the other inner cylinder fitting 2 side
By screwing a nut 8b onto a through a washer 7b, the inner cylinder 2 is connected to a mating member (not shown) on the vehicle body side.
Attached to. As a result, the end thick portion 4 of each bush member 1 is compressed and deformed in the axial direction by the pressing force applied to the washers 7a and 7b, and both ends of the arm eye 9 in the axial direction and the shafts of both washers 7a and 7b. It is pressed against the direction facing surface.

[0004] As described above, by inserting the bush for leaf spring into the arm eye 9 by press-fitting, the inner cylindrical fitting 2 is provided.
And the intermediate thick part 5 sandwiched in a state of being compressed and deformed by the arm eye 9 via the outer cylinder fitting 6, the arm eye 9
The spring characteristic against the vibration input in the direction perpendicular to the axis applied to the shaft is secured. Further, both end faces in the axial direction of the arm eye 9 via the outer tube fitting 6 and both washers 7a, 7b.
In the thick end portion 4 which is compressed and deformed in the axial direction by being sandwiched between the axially opposed surfaces, the spring characteristic with respect to the vibration input in the axial direction is ensured.

[0005]

However, when the leaf spring bush is inserted into a leaf spring of a large vehicle such as a truck to which a very large load is applied,
The press-fitting ratio of the rubber elastic body 3 pressed into the arm eye 9 is 20%.
Since the value is lower, if the torsion angle of the rubber elastic body 3 becomes large, a slippage occurs between the rubber elastic body 3 and the outer metal fitting 6 integrated with the arm eye 9, and the durability thereof is rapidly deteriorated. There is. On the other hand, it is conceivable to increase the press-fitting rate of the rubber elastic body to 20% or more. However, the press-fitting with such a high press-fitting rate causes irregular deformation of the rubber elastic body, so that the position of the inner cylindrical metal fitting is reduced. As a result, there is a problem that the shaft is irregularly deviated from the axial center position. As a result, it becomes very difficult to insert the bolt into the shaft hole of the inner cylindrical fitting 2 of both bush members 1 and it becomes difficult to pull out the bolt, so that the assembling work and the removing work of the leaf spring bush are smoothly performed. There was a problem that it could not be performed.

An object of the present invention is to solve the above-mentioned problem by increasing the press-fitting rate of a rubber elastic body to increase the durability against torsion of the rubber elastic body and to facilitate the assembling to a mating member. The purpose is to provide.

[0007]

In order to achieve the above object, the constitution of the first aspect of the present invention is characterized in that a cylindrical shaft fitting is provided at both axial ends of the shaft fitting in a radial direction. Equipped with a pair of outwardly extending flange portions and a cylindrical rubber elastic body disposed on the outer peripheral surface of the shaft fitting, the shaft fitting is inserted through a mating cylindrical member having a shorter axial length than the shaft fitting. By doing so, rubber elasticity is applied between the radially opposed surfaces of the outer peripheral surface of the shaft fitting and the inner peripheral surface of the mating cylindrical member and between the axially opposing surfaces of each flange portion and both axial end surfaces of the mating cylindrical member. A leaf spring bush elastically connected by a body, wherein a rubber elastic body is disposed in a cylindrical shape on an outer peripheral surface between a position near one end and a position near the other end of the shaft fitting, and is provided at one end. An annular first thick portion protruding in the radial direction and having an outer diameter larger than the inner diameter of the mating cylindrical member; And a cylindrical intermediate thick portion which is radially projected at at least two positions in the direction and whose outer diameter is larger than the inner diameter of the mating cylinder member and which is inserted by being press-fitted into the mating cylinder member. A first rubber elastic portion, and an annular second thick portion externally attached to the outer peripheral surface of the shaft fitting at the other end of the shaft fitting and having an outer diameter larger than the inner diameter of the mating cylindrical member at least at the other end. And a press-fitting rate of 20% or more in press-fitting the intermediate thick portion into the counterpart cylindrical member, and the first thick portion and the second thick portion by each flange portion. The first thick portion and the second thick portion are pressed against the axially opposite end surfaces of the mating cylinder member and the axially opposed surfaces of the flange portions by compressively deforming the portions in the axially opposed directions. I did it.

According to the first aspect of the present invention, the intermediate thick portion of the first rubber elastic portion that supports most of the radial load applied to the mating cylindrical member has a press-fit ratio of 20%.
By being press-fitted at the above-described high-pressure insertion rate, it is largely compressed in the radial direction, so that even if the torsion angle is increased by receiving a large load from the mating cylinder member, slippage is less likely to occur. Further, since the inner tube fitting is formed integrally and is not separated, the bolt can be easily inserted into the shaft hole. Therefore, the leaf spring bush can be easily attached to the mating member, and the bolt can be easily pulled out when removing the leaf spring bush.

In the leaf spring bush according to the first aspect, the outer diameter of the first rubber elastic portion is slightly larger than the inner diameter of the mating cylinder member on the outer peripheral surface of the press-fit portion of the mating cylinder member. May be fixed in advance by press-fitting the first rubber elastic part, and the first rubber elastic part in a state where the outer cylindrical metal fitting is fixed may be press-fitted into the mating cylindrical member. (Invention of claim 2). Thereby, after the first rubber elastic portion is press-fitted into the outer cylinder fitting in advance with a low press-fitting rate, it can be further press-fitted into the mating cylinder member so as to finally have a high press-fitting rate. The press-fitting operation is facilitated, and the internal cylinder fitting can be reliably prevented from being twisted due to irregular deformation of the first rubber elastic portion. In addition, it is possible to prevent the first rubber elastic portion from being damaged by friction with the mating cylinder member at the time of press-fitting into the mating cylinder member.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a leaf spring bush (hereinafter referred to as a rubber bush) according to the embodiment.
Is a cross-sectional view showing a state in which is attached to an arm eye 40 (a mating cylinder member) of a leaf spring of a large vehicle such as a truck. The rubber bush includes a bush part 10 and a shaft end stopper part 20.

As shown in FIG. 2, the bush portion 10 includes an inner cylindrical metal member 11 serving as a shaft metal member and a first rubber elastic member which is a cylindrical rubber elastic body bonded to the outer peripheral surface of the inner cylindrical metal member 11 by vulcanization. Part 12 and a first rubber elastic part 12
An outer tube fitting 16 is provided. The inner tube fitting 11 has a straight cylindrical shape and an axial length longer than that of the eye arm 40. The first rubber elastic portion 12 has a shape after vulcanization molding,
As shown in FIG. 3, the inner metal fitting 11 extends between one end (the right end in the drawing) in the axial direction and a position (a position near the other end) that is a predetermined distance x away from the other end (the left end in the drawing). It has a cylindrical shape and has an annular first thick part 13 protruding coaxially in the radial direction at one end in the axial direction. The outer diameter of the first thick portion 13 is larger than the inner diameter of the arm eye 40. In addition, the first rubber elastic portion 12 has two intermediate thick portions 14 and 15 that are adjacent to each other in the axial direction in portions other than the first thick portion 13. Intermediate thick part 14,1
Numeral 5 is a cylindrical shape that protrudes coaxially in the radial direction and has a substantially trapezoidal cross-sectional shape in the axial direction. The maximum outer diameter of the outer peripheral portion is larger than the inner diameter of the arm eye 40 and the first thickness. The outer diameter of the meat portion 13 is slightly smaller. The first rubber elastic portion 12 is generally formed as a rubber vulcanized product M by rubber vulcanization molding on the outer peripheral surface thereof in a state where the inner cylinder fitting 11 is set in a mold. Instead, after being formed of a single rubber elastic body, this is
1 may be inserted and fixed.

The first outer cylindrical member 16 is a thin metal pipe having a smooth surface, and has an annular flange portion 16a protruding radially outward at one axial end (right end in the figure). I have. The first outer cylindrical member 16 has an axial length substantially equal to the length of the first rubber elastic portion 12 excluding the first thick portion 13, and an inner diameter of the outer diameter of the intermediate thick portions 14, 15. Is slightly smaller. The rubber vulcanized molded product M is press-fitted from the other end side into the inside of the first outer metal fitting 16 from the flange portion 16a side, and the first thick portion 13 is formed into the flange portion 16a.
The bush part 1 is
It is formed as 0. Here, since the press-fitting ratio of the intermediate thick portions 14 and 15 of the first rubber elastic portion 12 is suppressed to about 10%, the press-fitting operation is easy. In addition, since the press fitting rate is low and the surface of the first outer cylindrical member 16 is smooth, damage to the intermediate thick portions 14, 15 due to press fitting can be prevented.

As shown in FIG. 4, the shaft end stopper portion 20 includes a second rubber elastic portion 21 which is a cylindrical rubber elastic body externally inserted on the outer peripheral surface of the inner cylindrical metal fitting 11, and a second rubber elastic portion 21. And a second outer cylinder fitting 23 fixed to the outer peripheral surface of the outer cylinder.
The second rubber elastic portion 21 has an axial length of the inner cylindrical metal member 11.
The dimension is slightly shorter than the area of the outer peripheral surface where the first rubber elastic portion 12 is not mounted (the area between the other end and the position separated from the other end by the predetermined dimension x). Has been slightly larger. On the other end side (left end in the figure) of the second rubber elastic part 21, an annular second thick part 22 protruding coaxially in the radial direction is provided. The outer diameter of the second thick portion 22 is larger than the inner diameter of the arm eye 40.

The second outer tube fitting 23 is a thin metal pipe, and has an insertion tube portion 23a and an annular flange portion 23b protruding radially outward at the other axial end (left end in the figure).
And The axial length of the insertion cylindrical portion 23a is shorter than the axial length of the arm eye 40 minus the axial length of the first outer cylinder fitting 16, and the outer diameter of the arm eye 40 is smaller than that of the arm eye 40. It is slightly larger than the inside diameter.
The second rubber elastic portion 21 is usually formed integrally as a rubber vulcanized product by rubber vulcanization molding with the second outer cylinder fitting 23 set in a mold. After the elastic body is formed as a single body, it may be inserted and fixed to the second outer tube fitting 23.

The bush portion 10 is pressed into one end opening of the arm eye 40 of the leaf spring from the other end side of the inner cylinder fitting 11, and the flange 16 a of the first outer cylinder fitting 16 is in contact with one end surface of the arm eye 40. And is fixed to the arm eye 40. By this press-fitting operation, the first
The outer tube fitting 16 is narrowed in the radial direction, so that the press-fit ratio of the intermediate thick portions 14 and 15 of the first rubber elastic portion 12 is the first
In addition to press-fitting to the outer tube fitting 16, a high press-fitting rate of 20% or more is achieved. As a result, the intermediate thick portions 14, 15
Although it will be largely compressed in the radial direction, the press-fitting is performed in two stages, the straight portion of the first outer cylindrical member 16 is long, and the intermediate thick portions 14 and 15 are formed in two ridges. As a result, no irregular deformation is caused by the press-fitting, so that the inner tube fitting 11 is arranged substantially coaxially with the arm eye 40 without being twisted.

Next, the center hole of the second rubber elastic portion 21 of the shaft end stopper 20 is externally inserted into the other end of the inner cylindrical metal fitting 11 which is press-fitted and fixed to the arm eye 40, and the arm eye 40
By press-fitting the second outer cylinder fitting 23 into the other end opening of
The shaft end stopper portion 20 is inserted until the flange portion 23b comes into contact with the other end of the arm eye 40.
Fixed to 0. At this time, there is a slight gap between the inner peripheral surface of the second rubber elastic portion 21 of the shaft end stopper 20 and the outer peripheral surface of the inner cylindrical metal fitting 11, and the axial end portion of the intermediate thick portion 14 and the second rubber elastic member. There is also a gap between the axial ends of the part 21.

Further, a bolt 32 is inserted into the shaft hole of the inner cylinder 11 from one end of the inner cylinder 11 via a ring-shaped washer metal (flange) 31, and from the other end of the inner cylinder 11. By screwing a nut 33 to the tip of the protruding bolt 32 via a washer fitting 31, the inner cylindrical fitting 11 is fixed to a vehicle body side member (not shown) which is a mating member. Further, by further screwing the bolt 32 into the nut 33, the washer fittings 31, 31 receive the pressing force in the axial direction and exert a pressing force in the direction opposite to each other. 2 The thick part 22 is compressed in the axial direction, and the washer fittings 31, 31 and the arm eye 4
0 are pressed against both end faces. Thus, the first thick portion 13
And the second thick portion 22 is compressed in the axial direction,
The axial end of the intermediate thick portion 14 and the axial end of the second rubber elastic portion 21 that face each other are close to each other. However, since the gap is previously provided between the two, as described above,
Since the mutual extension is absorbed in the gap, the contact of the distal ends is prevented. Further, the extension of the second rubber elastic portion 21 in the axial direction due to the compression is absorbed by the gap between the second rubber elastic portion 21 and the outer peripheral surface of the inner cylinder fitting 11.

The rubber bush assembled to the arm eye 40 as described above is subjected to vibration in the direction perpendicular to the axis applied to the arm eye 40 in the intermediate thick portion 14 sandwiched between the inner cylindrical fitting 11 and the arm eye 40 while being compressed and deformed. A spring characteristic with respect to the input is obtained. Further, in the first thick portion 13 and the second thick portion 22 which are compressed and deformed in the axial direction by being sandwiched between both end surfaces in the axial direction of the arm eye 40 and the axially opposed surfaces of both the washer fittings 31, 31, the axial direction The spring characteristic with respect to the vibration input is obtained.

In the embodiment configured as described above, the intermediate thick portions 14, 15 of the first rubber elastic portion 12 are press-fitted into the arm eye 40 at a high press-fit ratio of 20% or more, so that the diameter is increased. Because it is greatly compressed in the direction,
Even when the torsion angle is increased by receiving a large load from the arm eye 40, the intermediate thick portions 14, 15 are less likely to slip. As a result, the durability of the intermediate thick portions 14, 15 is enhanced. Also, with respect to the load applied in the axial direction of the rubber bush, the first thick portion 13 of the first rubber elastic portion 12 and the second thick portion 22 of the second rubber elastic portion 21 are connected to the arm eye 4.
Since both end surfaces of the rubber bush are pressed against the pair of washer fittings 31, the durability of the rubber bush in the axial direction is ensured.

Further, since the inner cylindrical metal member 11 is formed integrally and straight and is not separated, the bolt 32 can be easily inserted into the shaft hole thereof. It is easy to fix to the member, and it is easy to pull out the bolt 32 when removing the first rubber elastic portion 12 from the vehicle body side member. As a result, the workability of assembling and removing the rubber bush is improved.

In the present embodiment, the outer diameter of the first rubber elastic portion 12 which is slightly larger than the inner diameter of the arm eye 40 is formed on the outer peripheral surface of the press-fit portion of the first rubber elastic portion 12 into the arm eye 40.
The outer tube fitting 16 is fixed in advance by press fitting. That is, the first rubber elastic portion 12 can be press-fitted into the first outer cylindrical member 16 at a low press-fitting rate in advance, and then finally press-fitted into the arm eye 40 so as to have a high press-fitting rate of 20% or more.
The press-fitting operation of the first rubber elastic portion 12 at a high press-fitting rate is facilitated. Furthermore, the twisting of the inner tube fitting 11 can be reliably prevented,
Stable radial spring characteristics can be obtained. In addition, the reliability of the first rubber elastic portion 12 is ensured without being damaged by friction with the arm eye 40 at the time of press-fitting into the arm eye 40. Further, since the second outer metal fitting 23 having an outer diameter slightly larger than the inner diameter of the arm eye 40 is fixed in advance to the outer peripheral surface of the portion where the second rubber elastic portion 21 is inserted into the arm eye 40, the second rubber elasticity is secured. The portion 21 is not damaged by friction with the arm eye 40.

In the above-described embodiment, the first outer metal fitting 16 is fixed to the outer peripheral surface of the first rubber elastic portion 12.
If necessary, the first outer tube fitting can be omitted. Similarly, the second outer metal fitting 23 provided on the outer peripheral surface of the second rubber elastic portion 21 can be omitted. Further, the number of intermediate thick portions of the first rubber elastic portion is two, but may be three or more. Furthermore, the second rubber elastic portion may be simply the second thick portion without providing a portion to be inserted into the arm eye.

In the above embodiment, the case where the rubber bush is press-fitted into the arm eye for the leaf spring is shown. However, the present invention is not limited to this and can be similarly applied to similar uses such as a suspension bush. In addition, the rubber bush shown in the above embodiment is an example, and within a range not departing from the gist of the present invention,
It can be implemented in various forms.

[0024]

According to the first aspect of the present invention, the intermediate thick portion of the first rubber elastic portion is press-fitted at a high pressure input rate of 20% or more and is largely compressed in the radial direction. Even if the torsion angle is increased by receiving a large load from the member, it is difficult to slip. As a result, the radial durability of the rubber elastic body is enhanced, and the reliability of the leaf spring bush is enhanced. Also, since the inner cylinder is integrally formed and not separated, it is very easy to insert and remove the bolt from the inner cylinder, and as a result, assemble and remove the leaf spring bush to and from the mating member. Workability is improved.

Further, after the first rubber elastic portion is press-fitted into the outer cylinder at a low press-fitting rate in advance, the first rubber elastic portion is further press-fitted into the mating cylinder member so as to finally have a high press-fitting rate of 20% or more ( According to the second aspect of the present invention, the press-fitting operation of the first rubber elastic portion at a high pressure rate can be facilitated, and the irregular deformation of the first rubber elastic portion can be prevented, so that the inner cylindrical metal fitting can be more reliably prevented from being twisted. Can be avoided. Also, when press-fitting into the mating cylinder member, the first
The rubber elastic portion is not damaged by friction with the mating cylinder member, and its reliability is ensured.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a state in which a leaf spring bush according to an embodiment of the present invention is mounted on an arm eye of a leaf spring of a vehicle.

FIG. 2 is a cross-sectional view showing a bush portion in which a rubber vulcanized molded product is pressed into an outer cylinder.

FIG. 3 is a cross-sectional view showing a rubber vulcanized molded product obtained by vulcanizing and molding a rubber elastic body on an inner cylinder.

FIG. 4 is a sectional view showing a shaft end stopper portion.

FIG. 5 is a partial cross-sectional view showing a state in which a conventional leaf spring bush is mounted on an arm eye of a leaf spring of a vehicle.

FIG. 6 is a cross-sectional view showing a bush member in which a rubber vulcanized molded product as a conventional example is press-fitted into an outer cylinder.

FIG. 7 is a cross-sectional view showing a rubber vulcanized molded product obtained by vulcanizing and molding a rubber elastic body on an inner cylinder fitting as a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... bush part, 11 ... inner cylinder fitting, 12 ... 1st rubber elastic part, 13 ... 1st thick part, 14, 15 ... middle thick part, 1
Reference numeral 6: first outer metal fitting, 16a: flange portion, 20: shaft end stopper portion, 21: second rubber elastic portion, 22: second thick portion,
23: second outer cylinder fitting, 31: washer fitting, 32: bolt, 33: nut, 40: arm eye.

Claims (2)

[Claims] 1. A cylindrical shaft fitting, and a pair of flanges disposed at both axial ends of the shaft fitting and extending radially outward,
A cylindrical rubber elastic body disposed on the outer peripheral surface of the shaft fitting, wherein the shaft fitting is inserted and arranged in a mating cylindrical member having a shorter axial length than the shaft fitting, thereby forming the shaft. By the rubber elastic body, between the radially opposing surfaces of the outer peripheral surface of the metal fitting and the inner peripheral surface of the mating cylindrical member and between the axially opposing surfaces of the flange portions and the axial end surfaces of the mating cylindrical member, respectively. An elastically connected leaf spring bush, wherein the rubber elastic body is disposed in a cylindrical shape on an outer peripheral surface between a position near one end and a position near the other end of the shaft fitting, and is provided on the one end side. An annular first thick portion which is radially projected and whose outer diameter is larger than the inner diameter of the counterpart cylindrical member; A cylindrical intermediate member which is larger than the inner diameter of the cylindrical member and which is inserted by being press-fitted into the mating cylindrical member. A first rubber elastic portion having a thick portion; an outer diameter of the other end of the shaft fitting being externally inserted into an outer peripheral surface of the shaft fitting and having an outer diameter at least on the other end side of the inner diameter of the mating cylindrical member; A second rubber elastic portion having a larger annular second thick portion, and a press-fitting ratio of 20% for press-fitting the intermediate thick portion to the mating cylindrical member.
As described above, the first thick portion and the second thick portion are each compression-deformed in the axially opposing directions by the respective flange portions, so that both axial end surfaces of the mating cylindrical member and the shafts of the respective flange portions are formed. A bush for a leaf spring, wherein the first thick portion and the second thick portion are pressed against a direction facing surface. 2. A thin outer cylindrical metal fitting whose outer diameter is slightly larger than the inner diameter of the mating cylinder member is formed on the outer peripheral surface of the press-fit portion of the first rubber elastic portion into the mating cylinder member. 2. The method according to claim 1, wherein the first rubber elastic portion in a state where the outer cylinder is fixed is press-fitted into the mating cylinder member.
A bush for a leaf spring according to item 1.