JPS584217B2 - air spring for vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is particularly applicable to
BOLSTERLESS) The purpose of this invention is to provide an air spring for vehicles that is highly wear resistant and has a long service life, to be installed in a vehicle consisting of a bogie.

In conventional vehicles, air springs were installed on the vehicle with a bolstered bogie, and it was hoped that this would provide a cushioning effect, but recently, bolsterless bogies have been adopted in order to reduce the weight and cost of vehicles. Ta.

However, the torsional displacement applied to the air spring in this vehicle is large, especially when the vehicle is meandering or turning during driving.More specifically, the torsional displacement applied to the air spring is torsional displacement in the longitudinal direction centered on the center plate pin, so the air spring A specific part of the flexible member causes sliding motion and a large friction phenomenon between the top plate and the bottom plate, which accelerates mechanical aging of the surface rubber of the flexible member and causes significant wear. This accelerated the process and led to early breakage.

Therefore, in the past, rubber was vulcanized and bonded to a metal top plate, and the axial cross section of the rubber part was tapered outward to reduce the lateral rigidity of the air spring itself and to reduce horizontal displacement. Although consideration was given to increasing the amount, it was not possible to obtain a sufficient effect.

Therefore, the air spring must be replaced within a short period of time, which is a serious problem in terms of maintenance and management of the vehicle.

In addition, the air springs for vehicles equipped with the above-mentioned bolsterless bogie are two air springs installed in one bogie, and are placed in two places, one at the front and the other at the rear of the vehicle. When this is done, the outer portions of the flexible members of the air springs in contact with the upper and lower rigid wall surfaces are subjected to extreme torsional displacements, the repetition of which causes significant friction in the areas of contact with the upper and lower faceplates.

That is, extreme wear occurred in the diagonally shaded area (area b ADCE) on the outside with respect to the center of the vehicle in FIG.

Conventional air springs consist of upper and lower rigid walls and flexible members, and the upper and lower rigid walls are made of metal or synthetic resin plates or blocks, or metal and plastic parts, depending on where they are used. Rubber or a composite of metal and synthetic resin is used as appropriate, and special shapes such as tapered shapes are considered in order to give the air spring different characteristics.

That is, the rigid walls above and below the air spring refer to various types of walls made of highly rigid metal or synthetic resin.

In addition, the shape of the flexible member can be a single toroid type or a bellows type, and as a reinforcing material, a steel cord or textile cord is buried in a rubber layer depending on the purpose, and the end of the buried reinforcing layer is The bead portion is folded back and fixed to a bead core such as a bead wire or a rigid ring, and the bead portion in which this bead core is embedded is hermetically fixed at the upper and lower portions to a rigid wall body by a self-sealing method or a fastening method. .

In particular, in the above-mentioned air springs for bolsterless trolleys, the rubber layers in contact with the upper and lower rigid walls of the flexible member are subject to marked wear and tear, and the reinforcing layer is exposed at an early stage, leading to cord breakage. Eventually, it bursts and becomes unusable.

Recently, in order to eliminate these drawbacks, a method has been adopted in which a metal plate or a synthetic resin plate made of polyethylene, polypropylene, etc. is attached to the metal part of the top plate via rubber at the mounting point. This was insufficient when lateral displacement was required.

Therefore, as a result of investigating the state of the outer covering rubber of the flexible member during the operation of the air spring, the inventors found that no matter how low the friction coefficient material is used, continuous and repeated pressure contact operation is impossible. It was discovered that it is impossible to prevent the mechanical aging of the rubber and the tendency of the temperature to rise, which in turn leads to wear and tear. It was concluded that good results could be obtained by interposing a synthetic fiber network in a non-adhesive state between the rigid walls of.

With this structure, during pressure welding, the net-like body partially bites into the outer cover rubber surface to exhibit fixation, and a mesh pattern of synthetic fibers is formed on the surface to cope with rolling and sliding action. As a result, the mesh is freely deformed and provides a sliding action between the rigid wall surface and the synthetic fiber network.

Therefore, the mesh of the rubber on the surface of the rubber sheath of the flexible member limits the repeated stretching and compression action, and the pressure friction is indirectly performed by the mesh of synthetic fibers, which prevents mechanical aging of the rubber. It is thought that the tendency of the temperature to increase was significantly suppressed, and the coefficient of friction was also lowered, so that the conventional wear and tear problems were eliminated.

In addition, since the mesh provides a sliding action, it also has the feature of reducing the spring constant of the air spring in the lateral direction.

The synthetic fiber network used in the present invention is preferably a mesh fabric forming a knotless network, such as a lattice lace knit.

The mesh body is formed into a donut shape with the center cut out, and is used as an intermediary between the circular rigid wall body and the flexible member of the air spring, and the fibers used are natural fibers. Fibers with less fuzz, such as heat-treated polyamide fibers, polyester fibers, and vinylon fibers, are preferred since they have a drawback in durability due to their large amount of fuzz.

In addition, in order to extend the wear life of this synthetic fiber network, it is necessary to use thick threads or to add wear resistance and rigidity to the peripheral fiber forming part of the network by processing it with resin. It is.

Note that although the mesh size differs depending on the knitting form, it is usually used that has a mesh size in the range of 1 mm or more and 6 mm or less.

The use of this synthetic fiber network is as described above, but
Depending on the operating state of the air spring, the synthetic fiber network may be interposed only between the upper rigid wall and the outer rubber of the flexible member, and in some cases, the lower rigid wall may be the opposite. In some cases, a synthetic fiber network is interposed between the flexible member and the outer covering rubber of the flexible member.

Next, aspects of the present invention will be specifically described based on drawings showing examples.

Figure 1 is a plan view of a top plate as a rigid wall on the upper part of a conventional air spring. It is a plan view shown in the shaded area, and is as described above.

2 and 3 are longitudinal cross-sectional views showing an example of the air spring of the present invention, and FIG. 4 shows the mesh of the synthetic fiber mesh interposed between the top plate and the flexible member in the case of displacement in the a direction. Fig. 5 is an enlarged plan view showing the position of the deformation tendency of the mesh in the opposite direction (direction a in Fig. 5). It is an explanatory diagram of a position, and is an enlarged plan view showing a deformation tendency depending on the density of lines.

Next, the embodiment shown in FIG. 2 will be described.

In this embodiment, a synthetic fiber network is interposed between the lower rigid wall and the outer rubber of the flexible member.

In the figure, 1 is the flexible member of the air spring, 1a is the reinforcing material, 1b is the bead core, B is the bead part where the bead core is embedded, 1c is the outer cover rubber, 1d is the inner rubber, and TRW is the circular upper rigid wall. In this example, an annular body is formed by adhering or vulcanizing a low-friction sliding plate 2c such as a polished metal plate or synthetic resin to a rubber block 2b to a circular structure consisting of an upper metal plate 2a and a stopper holder 10. The upper rigid wall body is constructed by fixing them together to form an inclined part and a bead seal part BS.

In this example, a synthetic resin plate was used for the sliding plate 2c.

In this example, the circular lower rigid wall body BRW is composed of a circular lower metal plate 3, a fitting sliding plate 5 made of metal or synthetic resin, and a bead presser 6. Although synthetic resin was used for the plate 5, in the case of metal, a polished surface of rust-free steel is preferable.

That is, the sliding plate 5 fits on the periphery of the circular metal plate 3.
are fixed to form a sliding surface, and the lower metal plate 3 and bead presser 6 are tightened with bolts to fix the bead part B so as to seal it, and 7 is a stopper.

As shown in this embodiment, the present invention is characterized in that sliding plates made of synthetic resin or rust-free steel are fixed to the inner surfaces of the upper and lower rigid walls in contact with the outer rubber of the air spring, or coating or directly forming a polished surface, etc.
In short, the goal is to form a smooth sliding surface on the inner surface.

The synthetic resin is preferably a fluororesin, but is not limited to this.

That is, the air spring of this embodiment is installed in a vehicle by interposing the synthetic resin net 4 between the lower rigid wall body BRW having a smooth sliding surface formed on the inner surface and the outer cover rubber 1c of the flexible member 1. This constitutes an air spring for use in the air.

Reference will now be made to the embodiment of FIG.

In this example, a synthetic fiber network is interposed between the upper rigid wall and the outer rubber of the flexible member.

In the figure, the upper rigid wall TRW has an inclined metal plate 2a' deformed to the inner shape of the rubber block 2b instead of the upper metal plate 2a in FIG. 2, and a smooth inner surface made of a synthetic resin plate. The sliding plate 2c is bonded and a bead seal portion BS is formed between the sliding plate 2c and the stopper pedestal 10, and as described above, a smooth sliding surface is formed on the inner surface of the upper rigid wall.

In addition, the lower rigid wall BRW has a fitting sliding plate 5 in FIG.
The total shape of the lower metal plate 3 and the lower metal plate 3 is one lower metal plate 3a, and this is made up of a sliding plate 8 made of a synthetic resin plate and a bead presser 6, and a sliding plate made of synthetic resin is attached to the periphery of the circular lower metal plate 3a. A plate 8 is bonded to form a sliding surface, and a bead portion B is sealed with a bead presser 6.

As described above, the air spring of this example has smooth sliding surfaces formed on the inner surfaces of the upper and lower rigid walls, and the upper rigid wall TRW and the flexible member 1 with smooth sliding surfaces formed on the inner surfaces.
A synthetic fiber network body 9 is interposed between the outer cover rubber 1c and the air spring for a vehicle.

As mentioned above, the upper and lower rigid walls are appropriately selected depending on the location and purpose of use, such as plate-shaped bodies, block bodies, or composite bodies. It only needs to be a rigid wall; if it is made of synthetic resin, it should have a polished or sliding surface on its inner surface; if it is made of metal,
A polished surface of a rust-resistant metal is preferred.

The effect of the operation of the synthetic fiber network interposed between the sliding surfaces of metal or synthetic resin is as explained above, and the trends in the changes in the network are summarized in Figures 4 and 5. show.

This change in the mesh is complex and difficult to display, so the drawing is shown as an enlarged line diagram to explain the tendency.The mesh forms a fixed, almost square mesh as seen in lace knitting. It is a material that undergoes minute deformations within the range of the mesh.

The self-produced fiber networks 4 and 9 used have a donut shape with the center cut out, so that when the air spring is lateral displaced, the lower rigid wall side is fixed, and the upper rigid wall side is In the case of relative displacement along the direction (direction of displacement), if the donut-shaped synthetic fiber network is divided into 8 parts as shown in Figures 4 and 5, then a is the position in the displacement direction. , a' indicates the position in the opposite direction, and b indicates the displacement direction aa
If c is the midpoint between a and b, and c is the midway point between a' and b, then the operation at a and a' is a rolling motion. is the main force, and the operation at positions b and b is mainly caused by slipping.

Therefore, part a is pressed and displaced by the upper rigid wall, so its movement is restricted and there is no deformation of the mesh, but part b is deformed by sliding and the mesh is expanded, so c'
The deformation tendency from the part to the a' part also expands.
The part c shows a tendency to deform by being compressed and narrowing the interval between the meshes.

Further, in the figure, when upward displacement and downward displacement are performed simultaneously, the position of portion c' also shows deformation such that the mesh interval becomes narrower.

The mesh of the synthetic fiber network used in this example was made of approximately 3 mm square raschel lace knitting, forming a fixed mesh of up to 3 mm on one side. There is a slight deformation between the sliding surface and the sliding surface within the rectangular area, and FIGS. 4 and 5 are enlarged views of the tendency, and the length of one side does not change as shown.

In other words, when pressurized air is fed into the air spring, the mesh of the synthetic fiber network partially bites into the outer rubber surface of the flexible member 1 and is fixed, as if a slider was being worn on the flexible member. ), which indirectly causes sliding friction between the sliding surface and the synthetic fiber network, which not only prevents wear of the outer rubber but also significantly reduces the aging factor of the rubber. It is possible to maintain the physical properties of the rubber for a long time,
This contributes to improving the durability of the air spring.

Next, a durability test, a lateral displacement test, and a spring constant test will be conducted on this example, and the features of the present invention will be explained in comparison with conventional products.

(B) Durability test The durability test calculates the lifespan to be 4 years if it is subjected to repeated vertical movement 60,000 times per year under the following conditions, by converting it into a large displacement and taking into account the results of the actual vehicle driving test. I assumed it and did it.

Test conditions Air spring height: 140 mm Pressure: 5 kg/cm2 Repetition cycle: 0.5 Hz Stroke: ±81 mm The following table shows the results of testing the conventional air spring and the air spring of the present invention under the above test conditions.

(b) Lateral displacement test Figure 6 shows an air spring height of 140 mm and a pressure of 5 kg/
This shows the lateral stiffness diagram in cm2, and the horizontal axis is the lateral displacement (
mm), and the vertical axis shows the load (kg).

The hysteresis curve (1) represents the characteristics of the conventional product, and the fact that the curve is upright indicates that the spring is stiff.

The hysteresis curve shown by the dotted line in (2) is the air spring of the present invention, and the curve is bouncing.

In other words, this indicates that the spring is soft.

(c) Spring constant test Figure 7 shows the spring constant diagram when the air spring is lateral displaced at a height of 140mm±40mm, and the horizontal axis is the pressure (kg).
/cm2), and the vertical axis indicates the spring constant (kg/mm).

The spring constant diagram (1) represents the characteristics of the conventional product, and increases in direct proportion to the internal pressure.

The spring constant diagram (2) shows the characteristics of the vehicle air spring of the present invention, which shows an almost flat constant spring constant regardless of the internal pressure and a much lower value than conventional products. ing.

As mentioned above, the air spring for vehicles of the present invention not only has outstanding wear resistance and durability compared to conventional products, but also has soft lateral displacement, low spring constant, and a spring that does not change regardless of internal pressure. It has excellent performance that cannot be found in conventional products that exhibit constant values.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the upper surface plate contact portion (hatched area) of the early failure point of a conventional air spring, and Figs. 2 and 3 are
FIGS. 4 and 5 are longitudinal cross-sectional views of an embodiment of the air spring for vehicles of the present invention, and FIGS. The figure shows the lateral stiffness diagram of the product of this invention and the conventional product, No. 7.
The figure is a spring constant diagram of the product of this invention and a conventional product. TRW...Top rigid wall, BRW...
Lower rigid wall body, 1...Flexible member, 1c...
...Rubber covering, 4,9...Synthetic fiber network.

Claims (1)

[Scope of Claims] 1. An air spring in which a flexible member of an air spring is airtightly mounted between an upper and lower rigid wall having a smooth sliding surface formed on the inner surface, wherein the upper rigid wall and the flexible 1. An air spring for a vehicle, characterized in that a synthetic fiber network is installed with a synthetic fiber network interposed between a rubber jacket of a flexible member or between a lower rigid wall and a rubber jacket of a flexible member. 2. The air spring for a vehicle according to claim 1, wherein the peripheral fiber forming portion forming the network of the synthetic fiber network is processed with synthetic resin.