JPH0121384B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a diaphragm for an air spring, in which a reinforcing member in the form of a band is embedded spirally in a cylinder made of rubber or a rubber-like elastic body in the longitudinal direction of the cylinder. Diaphragms of this type are becoming widely used, for example, in automobile suspensions as shown in FIG. This suspension 1 has an outer shell 4 fixed to the rod 3 of the shock absorber 2, and an intermediate part or end of the outer shell 4 and the outer cylinder 5 of the shock absorber 2.
Each end of a cylindrical air spring diaphragm 6 is fixed. Here, the diaphragm 6 is folded back toward the opposite side of the outer shell 4 so that its cross-sectional shape is approximately U-shaped.
A sealed space is formed between the outer cylinder 5 and the outer shell 4, and a spring action is produced in cooperation with the compressed air sealed therein. A conventional air spring diaphragm used for such a purpose is, for example, as shown in FIG. Each reinforcing member 9 is in the form of a band having an intersection angle of 60° to 60°, and has two inner and outer layers.
a and 9b are buried symmetrically and spirally. In addition, when embedding the reinforcing members 9a and 9b, in order to prevent the cylindrical body 8 from being punctured and furthermore to prevent a decrease in manufacturing accuracy due to winding misalignment of the reinforcing members 9a and 9b, each The widthwise end portions of the reinforcing members 9a and 9b are overlapped by a width of 1 to 10 mm. Therefore, according to this prior art, when used, the rigidity of each overlapping portion of the reinforcing members 9a, 9b is higher than that of the other portions, and the cylindrical body 8
This change in rigidity in the longitudinal direction causes localized stress concentration on the diaphragm, often causing its breakage, as well as the problem of air leakage due to the reinforcing members 9a and 9b being exposed from the cylindrical body 8. It was hot. Therefore, by increasing the overall wall thickness of the cylinder 8 to increase the overall rigidity of the diaphragm and preventing the reinforcing members 9a and 9b from being exposed, the rigidity change in the longitudinal direction of the cylinder 8 is improved. Attempts have been made to improve the durability of the diaphragm by reducing the size of the diaphragm and preventing air leakage. However, when a diaphragm with a thickened cylindrical body 8 is used as described with reference to FIG. Since the radius of curvature in the vicinity of the inner circumferential surface is particularly small, the fibers and rubber material that constitute each reinforcing member 9a, 9b are seriously damaged due to friction between the fibers and the rubber material surrounding them. While the diaphragm suffers from early bending fatigue, it also has the problem of not being able to provide an air spring with good riding comfort. The present invention advantageously solves the problems of the prior art, and in particular, when a diaphragm is used, at least the reinforcing member located on the outside can be embedded in the cylinder without overlapping it in the longitudinal direction of the cylinder. This prevents the reinforcing member from being exposed from the rubber material, prevents damage to the diaphragm due to changes in rigidity in the longitudinal direction of the cylinder, and also makes it possible to reduce the thickness of the cylinder. The present invention also provides a diaphragm that prevents damage to the rubber material and sufficiently improves riding comfort. The present invention will be explained below based on the drawings. FIG. 3 is a partial sectional view showing an embodiment of the present invention, and in this example, as described in connection with FIG.
For example, reinforcing members 9a and 9b of two layers, an inner and outer layer, are embedded in a spiral shape within a cylinder 8 made of rubber. Here, a portion outside the reinforcing member 9b located on the outside is shown as a cross section, but the reinforcing member 9a located on the inside (not shown) is
It extends symmetrically. For example, among the band-shaped reinforcing members 9a and 9b made by weaving nylon fibers in the shape of a blind and further coating with rubber or other elastic material, in this example, the reinforcing member 9b, which is arranged on the outer side, extends in the length direction of the cylinder 8. Rather, preferably 0.2 to 5 mm, as shown in the enlarged cross-sectional view in Figure 4, without overlapping.
The reinforcing member 9b is vulcanized and bonded to the inner reinforcing member 9a and the outer rubber layer 8a, respectively. When using such a diaphragm 6, the third
By folding the left end of the figure inward and fixing it to the outer shell 5, and fixing the right end of the figure to the outer shell 4, the reinforcing member 9b placed on the outside is positioned on the outside when the diaphragm 6 is used. Become. On the other hand, when using the diaphragm 6, when the left end in the figure is fixed to the outer cylinder as it is and the right end is folded back to the outside and fixed to the outer shell 4, the reinforcing member 9a placed on the inside should be located on the outside. Therefore, in this case, the reinforcing member 9a is positioned in the same manner as the above-mentioned reinforcing member 9b, and vulcanization bonding is performed. Although not shown, it goes without saying that the inner reinforcing member 9a may also be positioned in the same manner. According to the diaphragm formed by embedding the reinforcing member 9b in this manner, the stiffness in the longitudinal direction becomes relatively uniform, especially since there is no overlap in the width direction of the reinforcing member 9b, so that stress concentration is alleviated. This improves the durability of the diaphragm. On the other hand, even if the wall thickness of the cylindrical body 8 is made thinner, there is no risk of air leakage due to exposure of the reinforcing members 9a and 9b, and this reduction in wall thickness not only causes a decrease in the rigidity of the entire diaphragm but also reduces its deformation. Since the difference in the amount of deformation between the inner and outer circumferential surfaces is reduced, excellent riding comfort of the vehicle is ensured, and the reinforcing member 9b
And damage caused by rubber friction is effectively prevented. By the way, the results of a bench durability test comparing the diaphragm of this invention with a conventional one are as follows:
It is as follows. Conditions: Pressure 8.5Kg/cm ² gage, temperature 75℃, frequency 3.5Hz, stroke ±50mm Results

[Table] As is clear from this table, the diaphragm of the present invention provides at least three times the durability of the conventional product. Although this invention has been described above with reference to the illustrated example, it is also possible to construct the reinforcing member with fibers other than nylon fibers. Therefore, according to the present invention, by eliminating the overlap of reinforcing members in particular, it is possible to obtain a diaphragm that has excellent durability and provides sufficient ride comfort, and also reduces costs by reducing the amount of raw materials used. can bring.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing how the diaphragm is applied, FIG. 2 is a side view showing a conventional example, FIG. 3 is a partial sectional view showing an embodiment of the present invention, and FIG.
It is an enlarged sectional view of the figure. 8... Cylindrical body, 9a, 9b... Reinforcement member.

Claims (1)

[Claims] 1. In a diaphragm in which a band-shaped reinforcing member is embedded spirally in the longitudinal direction of the cylindrical body made of rubber or a rubber-like elastic body, when the diaphragm is used, at least the reinforcing member located on the outside is A diaphragm for an air spring characterized by being embedded without overlapping in the length direction of a cylindrical body.