JP2000097273A - Rolling sleeve type air spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate rustproofing treatment of a piston surface and welding with a piston base on a piston bottom part and to self-seal a lower end bead part of a diaphragm. SOLUTION: A diaphragm 20 is molded long, a piston 21 is formed cylindrical, a piston base 23 is accumulated on a lower end of the piston 21 free to connect and siconnect to and from it, a lower half part of the diaphragm 20 is inserted into the inside of the piston 21 and accumulated, a lower end bead part 20d of the diaphragm 20 is positioned between the lower end of the piston 21 and a bead ring 23c projected on the piston base 23, the piston 21 is installed with pressure on the piston base 23 through the diaphragm 20 by internal pressure charged in the diaphragm 20 and the lower part bead part 20d of the diaphragm 20 is fitted on a tapered outer surface of the bead ring 23c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling sleeve type air spring having a cylindrical rubber diaphragm and a piston, wherein a connection between the diaphragm and the piston is self-sealed.

[0002]

2. Description of the Related Art In a rolling sleeve type air spring, a piston is connected to one end of a cylindrical diaphragm made of rubber and a reinforcing cord, and a part of the diaphragm comes into rolling contact with the piston surface as the piston moves up and down. There is a known diaphragm in which both ends of the diaphragm are self-sealed. FIG. 4 shows an example, in which the diaphragm 10 is formed into a cylindrical shape with rubber containing a plurality of layers of reinforcing cords, and its upper end bead portion 10a protrudes from the lower surface of the end plate 11 covering the opening. The lower end bead portion 10b is fitted to the tapered outer surface of the bead receiving portion 11a.
Bead receiving portion 12 formed into a small-diameter cylindrical shape through 2a
b and fitted to the tapered outer surface
The inner surface of the upper plate 11 and the step 1 of the piston 12 at an internal pressure of 0
2a is pressed and sealed on the upper surface.

[0003] A piston base 13 is fitted into a lower end of the piston 12, and an outer peripheral portion thereof is hermetically fixed by welding. A cap nut 14 is screwed into a center hole 13a formed in the piston base 13 from above.
Airtightly fixed by welding with a facing downward. The piston 12 is fixed to, for example, the axle side of the vehicle using the screw holes 14a, and the end plate 11 is fixed to the vehicle body side of the vehicle using the screw holes 11b that are opened at a plurality of locations on the upper surface thereof.
An air pipe (not shown) is connected to the center hole 11 c of the end plate 11, and pressurized air fills the inside of the diaphragm 10 and the piston 12 with the air pipe.

In the above-described apparatus, since the internal space of the diaphragm 10 communicates with the internal space of the piston 12 through the lower end opening (the upper end opening of the piston 12), the volume of air entering is larger than the volume of the diaphragm 10 alone. Accordingly, the spring constant can be set smaller accordingly, and the upper end bead portion 10a of the diaphragm 10 can be self-sealed to the lower surface of the end plate 11 and the lower end bead portion 10b can be self-sealed to the upper end of the piston 12 by the internal pressure.
Is easy to install. However, diaphragm 1
The lower portion of the lower bead portion 10b is bent downward and comes into contact with the outer surface of the piston 12 made of steel plate. The rolling contact of the diaphragm 10 as the piston 12 moves up and down makes the outer surface of the piston 12 rust-resistant paint or plating. The layers peeled off and maintaining the airtightness at the weld of the piston base 13 to the piston 12 was costly.

[0005]

SUMMARY OF THE INVENTION The present invention provides a rolling sleeve type air spring in which a piston is provided at one end of a cylindrical diaphragm, which eliminates the need for rust-proofing of the piston and welding of the piston base at the bottom of the piston, and of the diaphragm. This enables self-sealing of the lower bead portion.

[0006]

According to the rolling sleeve type air spring of the present invention, an end plate is fixed to an upper end of a cylindrical diaphragm made of rubber and a reinforcing cord, a piston is connected to a lower end, and as the piston moves up and down. In a rolling sleeve type air spring in which a part of the diaphragm is brought into rolling contact with the piston surface, the diaphragm is formed to be longer by an amount corresponding to the piston length, while the piston is formed in a cylindrical shape, and At the lower end, a piston base that closes the lower end is detachably stacked, and the lower half of the diaphragm is inserted inside the piston and overlapped,
The lower end bead portion of the diaphragm is located between the lower end of the piston and a bead ring protruding on the piston base, and the piston is crimped on the piston base via the diaphragm with the internal pressure filled in the diaphragm, and The lower end bead portion of the diaphragm is fitted to the tapered outer surface of the bead ring.

That is, conventionally, when a piston is attached to one end of a diaphragm, a piston made of a rigid body is connected separately from the diaphragm in the direction in which the diaphragm is extended. However, in the present invention, the diaphragm is connected to the height of the piston. Is made longer than before, and this extension is inserted inside the cylindrical piston and overlapped. Then, the piston base is detachably overlapped with the lower end of the piston to close the lower end opening of the piston, and the lower end bead portion is provided between the lower end of the piston and a bead ring previously projecting on the piston base. Position, press down the piston through the diaphragm with air pressure in the diaphragm, press-fit this piston onto the piston base, and fit the inner surface or end surface of the lower end bead portion to the tapered outer surface of the bead ring to seal, That is, self-sealing is performed.

It is advantageous to use the inner or end face of the lower bead for this seal. For example, as in claim 2, a step is formed along the inner edge of the lower end of the piston, and a lower end bead of the diaphragm is formed in a ring-shaped groove formed by the step and the upper surface of the piston base. And the inner surface of the lower end bead portion can be fitted to the tapered outer surface of the bead ring. Further, as described in claim 3, the lower end side of the diaphragm is bent into an inward flange shape to be brought into contact with the piston base, and the end surface of the lower end bead portion can be fitted to the tapered outer surface of the bead ring. .

In the former (means of the second aspect), the internal pressure of the diaphragm pushes down the piston downward through a curved portion of the diaphragm along the upper edge of the piston, and the internal pressure of the diaphragm passes through a step at the lower end of the piston. The lower end bead of the diaphragm is directly pressed against the upper surface of the piston base, and the inner surface of the lower end bead is fitted to the tapered outer surface of the bead ring on the piston base to hermetically seal, so that a relatively strong sealing force is obtained. can get. On the other hand, in the latter (means of claim 3), the flange-like portion is pressed against the upper surface of the piston base by the internal pressure applied to the flange-like portion of the diaphragm end bent inside the piston, whereby the end surface of the lower end bead portion is formed. Since the bead ring on the piston base is fitted to the tapered outer surface and hermetically sealed, the bulge of the lower end bead portion can be formed on the inner surface side of the diaphragm, which facilitates forming.

As described above, according to the present invention, by filling the diaphragm with the internal pressure, the cylindrical piston is connected to the piston base, and the lower end bead portion of the diaphragm is fitted into the bead ring of the piston base and self-sealed. Since the piston is stopped, there is no need to make the piston from a weldable material and hermetically seal it with the piston base by welding.The piston can be made of aluminum alloy, magnesium alloy, synthetic resin, etc., which is unlikely to rust. The required rust prevention treatment is not required, and the piston and the piston base do not need to be hermetically connected by welding, so that the production becomes easy. In addition, since the piston and the piston base are detachable from each other as described above, only the diaphragm can be replaced while the end plate and the piston base are attached to the vehicle body or a mechanical device.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In FIG. 1, a diaphragm 20 is formed into a cylindrical shape with rubber containing a plurality of layers of reinforcing cords as in the prior art, and an upper end bead portion 20a is bulged inward at an upper end thereof. Is molded. The end plate 11 for sealing the upper bead 20a is shown in FIG.
In the same manner as the conventional one shown in FIG. 1, a ring-shaped bead receiving portion 11a protruding from the lower surface is provided, the outer surface thereof is tapered, the lower portion is formed to have a small diameter, and the ring-shaped bead is A plurality of screw holes 11b for connection to an upper body and a machine body are provided at a plurality of locations along the receiving portion 11a, and a screw hole 11c for connecting an air pipe is provided at the center.

The diaphragm 20 includes an upper end bead portion 20a, a main body portion 20b, an extension portion 20c corresponding to the height of the piston 21, and a lower end bead portion 20d.
The lower end bead portion 20d is formed so as to bulge outward. On the other hand, in the first embodiment, the cylindrical piston 21 is formed of a synthetic resin, the upper end of which is formed in a round edge having a semicircular cross section, and the lower end bead portion 20d of the diaphragm 20 is formed along the inner edge of the lower end. Step 2 corresponding to bulge
1a is recessed. Then, an extension 20c of the diaphragm 20 is inserted through the piston 21, an end face of a lower end bead 20d following the extension 20c is directed downward, and an outwardly bulging ridge of the lower end bead 20d is formed by the step. It fits with the part 21a.

The piston base 23 laid on the lower end of the piston 21 is made of metal such as iron.
A disk portion 23a having a size substantially equal to the outer diameter of the disk, a central projection 23b projecting upward at the center thereof, and a bead ring 23c surrounding the periphery thereof.
The outer surface of c is tapered, and the upper end is formed to have a small diameter. A screw hole 23d for connection to the base of the machine or the axle of the vehicle is provided in the center of the lower surface.

In the above structure, the lower piston base 23 is fixed to the base of the machine or the axle of the vehicle by using the screw holes 23d on the lower surface, and the upper end plate 11 is provided with a plurality of surrounding screw holes. The end plate 11 is connected to a machine main body or a vehicle body using an air pipe 11b. An air pipe is connected to a screw hole 11c at the center of the end plate 11, and the diaphragm 20 is filled with air of a predetermined pressure through the air pipe. When the air is filled, the piston 21 is pushed down by the pressure via the diaphragm 20 in contact with the upper end of the piston 21, and the step 21 a at the lower end of the piston 21 is
The lower end bead portion 20d is pressed down, the inner surface thereof is pressed along the outer surface of the bead ring 23c on the piston base 23, and the contact portion is air-tightly self-sealed.

Embodiment 2 Embodiment 2 shown in FIG. 2 differs from Embodiment 1 in that
The thickness of the piston 21 is reduced, the formation of the step 21a at the lower end is stopped, and the outer diameter of the bead ring 23c in the piston base 23 is reduced.
The lower end bead portion 20d is formed so as to bulge inward, and the lower end of the extension portion 20c of the diaphragm 20 is bent in an inward flange shape so that the end surface of the lower end bead portion 20d is formed into a bead ring of the piston base 23. The end face of the lower end bead portion 20d is brought into contact with the tapered outer surface of the lower bead portion 23d by the internal pressure applied to the flange-shaped curved portion.
c is pressed against the tapered outer surface and sealed.
Since the bulge of the lower end bead portion 20d is formed on the same inner surface side as the upper end bead portion 20a, the forming operation is facilitated.

Embodiment 3 Embodiment 3 shown in FIG. 3 differs from Embodiment 2 in that
At the upper end of the piston 21, a bead 21b having a diameter larger than the thickness of the lower portion is formed so as to expand toward the inner side without forming a depression on the outer side, and the curvature of the diaphragm 20 which is curved in contact with the upper end of the piston 21. The radius is increased to reduce surface distortion due to bending of the diaphragm 20.

[0017]

As described above, in the rolling sleeve type air spring of the present invention, the piston base is formed detachably with respect to the piston, and the piston is connected to the piston base by filling the diaphragm with the internal pressure. In addition, since the lower end bead of the diaphragm fits into the bead ring of the piston base to perform self-sealing, there is no need to air-tightly weld the piston and the piston base. It can be made of an aluminum alloy, a magnesium alloy, a synthetic resin, or the like, which is difficult, so that the rust prevention treatment that has been required conventionally becomes unnecessary and the production becomes easy. Further, since the piston and the piston base are detachable from each other as described above, only the diaphragm can be replaced while the piston or the piston base is attached to the vehicle body or a mechanical device.
In particular, according to the second aspect of the present invention, the lower end of the piston pushed down by the internal pressure of the diaphragm directly presses the lower end bead portion of the diaphragm to press the inner surface of the lower end bead portion against the tapered outer surface of the bead ring on the piston base.
A relatively strong sealing force is obtained. In the invention according to claim 3, the bulge of the lower end bead portion is formed on the inner surface side of the diaphragm, the lower end bead portion is curved so as to form an inward flange, and the end surface of the lower end bead portion is formed. Since the pressure is brought into contact with the tapered outer surface of the bead ring, the operation of forming the lower end bead portion is facilitated.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment.

FIG. 2 is a longitudinal sectional view of a main part of a second embodiment.

FIG. 3 is a longitudinal sectional view of a main part of a third embodiment.

FIG. 4 is a longitudinal sectional view of a conventional device.

[Explanation of symbols]

 11: End plate 11a: Bead receiving portion 11b, 11c: Screw hole 20: Diaphragm 20a: Upper end bead portion 20b: Main body portion 20c: Extended portion 20d: Lower bead portion 21: Piston 21a: Stepped portion 21b: Bead 23: Piston Base 23a: Disk portion 23b: Center protrusion 23c: Bead ring 23d: Screw hole

Claims (3)

[Claims] An end plate is fixed to an upper end of a cylindrical diaphragm made of rubber and a reinforcing cord, a piston is connected to a lower end, and a part of the diaphragm is brought into rolling contact with the piston surface as the piston moves up and down. In the rolling sleeve type air spring, the diaphragm is formed to be long by an amount corresponding to the length of the piston, while the piston is formed in a cylindrical shape, and a piston base for closing the lower end is detachably attached to the lower end of the piston. The lower half of the diaphragm is inserted inside the piston and overlapped, and the lower end bead portion of the diaphragm is located between the lower end of the piston and a bead ring protruding above the piston base to fill the diaphragm. The piston is pressed on the piston base through the diaphragm at the internal pressure that is applied, and the lower end bead of the diaphragm is pressed. A rolling sleeve type air spring, wherein a bead portion is fitted to a tapered outer surface of the bead ring. 2. A stepped portion is formed along the inner edge of the lower end of the piston, and a ring-shaped groove formed by the stepped portion and the upper surface of the piston base is provided with an outer ridge of a lower end bead portion of the diaphragm. 2. The rolling sleeve type air spring according to claim 1, wherein said lower end bead portion is fitted to said tapered outer surface of said bead ring. 3. The rolling sleeve type air according to claim 1, wherein the lower end of the diaphragm is bent into an inward flange shape so as to be in contact with the piston base, and the end face of the lower end bead portion is fitted to the tapered outer surface of the bead ring. Spring.