JP6974084B2 - Air spring - Google Patents

Description

The present invention relates to an air spring used in an automobile such as a truck or a bus or a railroad vehicle, and particularly to an air spring preferably used in a low-floor type vehicle.

As this type of air spring, as shown in FIGS. 1 and 2 of Patent Document 1, a diaphragm (cylindrical flexible member) 1 having a vertically oriented axial center P and an upper airtightly joined to the upper end thereof. An elastic stopper 14 that includes a plate 2 and a piston 3 that is airtightly joined to the lower end of the diaphragm 1 and that limits the relative displacement between the piston 3 and the upper plate 2 (restricts the deformation of the diaphragm 1) is above the piston 3. It is known that the piston is provided in a protruding state.

In the above air spring, the space inside the diaphragm exerts an elastic action as an air chamber, and even if an excessive load is applied to the air spring due to unevenness of the road surface due to the elastic stopper and the air spring bottoms out, the elasticity of the stopper causes the vehicle body. It is possible to alleviate the impact transmitted to. By the way, in recent years, the number of low-floor vehicles is increasing in buses and the like due to the convenience of getting on and off. When the air spring having the above configuration is used for the suspension of such a low-floor vehicle, as shown in FIG. 6 of Patent Document 1, the vehicle body 10 moves left and right around the rolling axis X at a low position away from the air spring. Roll to.

That is, since the upper plate 2 and the piston 3 are not only relatively displaced in the vertical direction but also relatively displaced in the horizontal direction, the elastic stopper may be used depending on the road surface condition on which the vehicle is traveling. It may interfere with (contact) the inner wall of the diaphragm (the inner wall of the diaphragm located on the center side of the vehicle body) or the joint between the diaphragm and the upper plate, which may affect the durability of the air spring.

In order to solve the above problem, as shown in FIG. 1 of Patent Document 2, an air spring having an elastic stopper attached at a position eccentric from the axis of the diaphragm (a position eccentric to the outside in the width direction of the vehicle body) is known. By adopting such a configuration, it is possible to suppress the interference of the elastic stopper with the diaphragm and improve the durability.

Japanese Unexamined Patent Publication No. 2016-125540 Japanese Unexamined Patent Publication No. 2016-125541

However, in the air spring described in Patent Document 2, as a support member for supporting the elastic stopper, the upper pipe material and the lower pipe material are welded to the upper and lower parts of the pedestal portion that can be fitted to the lower end of the diaphragm, and the upper pipe material is used. A support plate was welded to the upper end, and a bottom plate was welded to the lower end of the lower pipe material to use an integrated member.

As described above, in the air spring described in Patent Document 2, the structure of the support member is complicated, and when the air spring is assembled, the lower end of the diaphragm is fitted to the pedestal portion of the support member, and then the diaphragm. The piston is fitted to the pedestal part so as to sandwich the It becomes possible to pinch. As described above, the air spring described in Patent Document 2 has a complicated structure and complicated assembly work.

Therefore, in view of the above problems, it is an object of the present invention to provide an air spring that is easy to assemble and has excellent durability.

In order to achieve the above object, the air spring as one aspect of the present invention has an upper plate attached to a vehicle body, a cylindrical piston attached to an axle, and a cylinder interposed between the upper plate and the piston. An air spring including a flexible member having a shape, an elastic stopper, and a support member for supporting the elastic stopper. The lower end of the support member is fixed at the bottom of the piston, and the upper end thereof is the piston. The upper end of the support member is formed to have a diameter smaller than the upper opening diameter, and the elastic stopper is placed on a rigid reinforcing plate and the elastic stopper is placed. And the reinforcing plate are both characterized in that they are attached to the support member at a position eccentric from the axial center of the tubular flexible member so that a part of the reinforcing plate overlaps the upper opening edge of the piston in a plan view. ..

The support member may include a pipe material and a pedestal for attaching an elastic stopper fixed to the upper end of the pipe material, and may have a configuration in which an opening for communicating inside and outside is formed in the pipe material. Further, the bottom portion of the piston may be closed by the base plate, and the lower end of the support member may be fixed on the base plate.

In the air spring, a base plate with a support member obtained by welding a support member to the base plate is inserted into the lower opening of the piston from the support member side, and the upper end portion of the support member protrudes from the upper opening of the piston. In this state, the base plate is welded to the inner wall of the bottom of the piston all around to form a piston unit in which the support member and the piston are integrated, and the lower end of the flexible member is stopped at the upper end of the piston of the piston unit. After wearing, the elastic stopper can be mounted on the reinforcing plate, and both of them can be attached to the support member at a position eccentric from the axis of the piston.

According to the air spring according to one aspect of the present invention, the support member does not need to be provided with a pedestal portion in the middle as in the conventional case, the structure is simple, and the upper end portion of the support member is the upper opening diameter of the piston. Since the diameter is smaller than that of the piston, the upper end portion of the support member can be projected from the upper opening of the piston. Therefore, the elastic stopper can be set at a predetermined position only by attaching the elastic stopper to the upper end of the support member protruding from the piston, and an air spring that can be easily assembled can be obtained.

The elastic stopper is attached at a position eccentric from the axial center of the tubular flexible member and the support member, but the upper end surface of the support member is smaller than the upper opening area of the piston, and the elastic stopper is the support member in a plan view. By reinforcing the elastic stopper with a reinforcing plate having rigidity, it is possible to prevent the elastic stopper from being deformed even if a load is applied to the elastic stopper. Thereby, an air spring having excellent durability can be obtained.

A vertical sectional view showing an embodiment of the air spring of the present invention. Plan view of the elastic stopper of the air spring Plan view of the reinforcing plate of the air spring Top view of the pedestal of the air spring A plan view showing a state in which an elastic stopper placed on a reinforcing plate is attached to a pedestal. Schematic diagram showing the main parts of a low-floor bus equipped with air springs The figure which shows the trajectory of the relative displacement between the upper plate and the piston unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 5 are views showing an embodiment of the air spring of the present invention used for a low-floor bath, FIG. 1 is a vertical sectional view of the air spring, and FIG. 2 is a plan view of an elastic stopper used for the air spring. 3 shows a plan view of a reinforcing plate used for an air spring, FIG. 4 shows a plan view of a pedestal used for an air spring, and FIG. 5 shows a state in which an elastic stopper placed on the reinforcing plate is attached to the pedestal. The plan view is shown respectively.

As shown in FIG. 1, the air spring 1 of the present embodiment includes an upper plate 2, a cylindrical piston 3, a tubular flexible member 4 interposed between the upper plate 2 and the piston 3, and a tubular flexible member 4. It includes an elastic stopper 5 and a support member 6 that supports the elastic stopper 5. As the flexible member 4, a diaphragm or a bellows is used. In a stationary state in which the air spring 1 is mounted on the vehicle and the inside of the flexible member 4 is pressurized to the air pressure during normal use, the axis of the air spring is the upper plate 2, the piston 3, the flexible member 4, and the support member. Since it coincides with the axis of No. 6, the reference numerals of the axes of the members in this state are collectively referred to as P below.

As shown in the figure, the elastic stopper 5 is attached to the support member 6 eccentrically by a distance L from the axial center P of the air spring 1 (support member 6). The direction of eccentricity is the width direction outer side X1 of the vehicle body width direction X in the state where the air spring 1 is mounted on the bus. That is, the elastic stopper 5 is eccentric in the direction opposite to the inside X2 in the width direction in which the rolling axis A (see FIG. 6) is present.

In the present embodiment, as the flexible member 4, a diaphragm, which is an elastic film composed of a tubular laminated rubber having a reinforcing rubber layer in which a reinforcing cord is embedded as an intermediate layer, is used, and the upper end of the flexible member 4 is used. A thick upper bead portion 4a and a lower bead portion 4b in which a reinforcing rubber layer is wound around a bead core are formed in the portions and the lower end portions.

The upper plate 2 is configured by vertically stacking and integrating the upper plate 7 and the lower plate 8. Specifically, the upper plate 7 and the lower plate 8 are formed in a substantially disk shape, and the lower plate 8 has a slightly smaller diameter than the upper plate 7. The upper plate 2 is formed with a through hole 9 penetrating the upper plate 7 and the lower plate 8, and the bolt 10 penetrates from the lower side of the lower plate 8 as a fastening member for attaching the upper plate 2 to the vehicle body side member. It is fixed to the lower plate 8 in a state of being inserted through the hole 9.

A flange 8a formed one step lower over the entire circumference is provided on the outer peripheral side of the lower plate 8, and the upper bead portion 4a of the flexible member 4 is sandwiched between the flange 8a and the outer peripheral portion of the upper plate 7. There is. A communication pipe (not shown) penetrating the upper plate 7 and the lower plate 8 is arranged, and the communication pipe allows gas such as air in the flexible member 4 to be sucked and exhausted.

The piston 3 is formed by press-molding a metal cylindrical body, and has a tubular outer peripheral surface portion 3a, a shoulder portion 3b that curves upward from the upper end of the outer peripheral surface portion 3a and is folded inward, and a shoulder portion 3b. It is composed of a flat surface portion 3c formed at a position lower than the top of the shoulder portion 3b, and a cylindrical upper surface portion 3d formed so as to protrude upward from the flat surface portion 3c in the radial direction of the flat surface portion 3c. NS. The flat surface portion 3c is formed at a position lower than the top of the shoulder portion 3b.

The shoulder portion 3b has a shape that protrudes upward in a semicircular cross section on the entire circumference of the piston 3, an upper opening 11 (diameter D1) is formed in the center of the upper surface portion 3d, and the bottom portion of the piston 3 has a shoulder portion 3b. Is formed with a lower opening 12 having a diameter larger than that of the upper opening 11. An annular lower sheet 13 is fastened to the upper surface portion 3d by bolts. The inner diameter of the lower sheet 13 is the same as the diameter of the upper opening 11. A flange 13a formed one step lower over the entire circumference is provided on the outer peripheral side of the lower sheet 13, and the lower bead portion 4b of the flexible member 4 is sandwiched between the flange 13a and the flat surface portion 3c.

The support member 6 includes a pipe material 14 and a pedestal 15 for attaching an elastic stopper 5 fixed to the upper end of the pipe material 14 by welding or the like, and an opening 14a for communicating inside and outside is formed in the pipe material 14. .. The pedestal 15 is made of a metal disk and is formed to have a diameter slightly larger than that of the pipe material 14, and the diameter D2 of the pedestal 15 is set so that D2 <D1. A disk-shaped base plate 16 having a diameter slightly smaller than that of the lower opening 12 is fixed to the lower end of the pipe material 14 by welding or the like.

As shown in FIGS. 1 and 2, the elastic stopper 5 has a disk-shaped substrate 17 and a shape having a notch 18a, which is laminated on the substrate 17 and has a portion of a cylindrical shape cut out in the vertical direction. The elastic portion 18 of the above is provided. The notch 18a is provided on the inner side X2 in the width direction of the vehicle body. As a result, the elastic portion 18 is formed in a D-shape or a C-shape in a plan view. The elastic portion 18 is made of a rubber-like elastic body, and is concentric with the substrate 17 and has substantially the same diameter. A bolt hole 17a is formed in the center of the substrate 17. Further, on the lower surface of the substrate 17, a first convex portion 17b projecting downward is formed at a position away from the center of the substrate.

As shown in FIG. 3, the reinforcing plate 19 is made of a metal disk having a wall thickness substantially the same as that of the substrate 17. The characteristic of the reinforcing plate 19 is that the elastic stopper 5 is not deformed by the weight of the vehicle body applied to the elastic stopper 5 when air is released from the air spring 1 (at the time of deflate). A bolt hole 19a is formed in the center of the reinforcing plate 19. Further, a first receiving portion 19b for fitting the first convex portion formed on the substrate 17 is formed on the upper surface of the reinforcing plate 19. On the lower surface of the reinforcing plate 19, a second convex portion 19c projecting downward is formed at a position away from the center of the reinforcing plate 19.

As shown in FIG. 4, a screw hole 15a is formed in the pedestal 15 at a position eccentric from the axial center (axial center of the air spring 1) P of the pedestal 15 to the outer side X1 in the width direction of the vehicle body by a distance L. Further, on the upper surface of the pedestal 15, a second receiving portion 15b for fitting the second convex portion 19c formed on the reinforcing plate 19 is formed. The first convex portion 17b and the first receiving portion 19b, and the second convex portion 19c and the second receiving portion 15b function as a detent mechanism when bolting the elastic stopper 5.

When the elastic stopper 5 is attached to the support member 6, the bolt holes 17a of the elastic stopper 5, the bolt holes 19a of the reinforcing plate 19, and the screw holes 15a of the pedestal 15 are arranged concentrically, and the first convex portion 17b and the first After fitting the receiving portion 19b, the second convex portion 19c, and the second receiving portion 15b, respectively, the bolt 20 is inserted into the bolt holes 17a and 19a and screwed into the screw hole 15a. The first receiving portion 19b and the second receiving portion 15b may be recesses or through holes.

In the present embodiment, the first receiving portion 19b, the bolt hole 19a, and the second convex portion 19c are arranged so as to be aligned in a straight line in a direction orthogonal to the vehicle body width direction X in a plan view. As a result, when the elastic stopper 5, the reinforcing plate 19, and the pedestal 15 are fastened with the bolt 20, it is possible to tighten the elastic stopper 5 in a well-balanced manner while preventing the elastic stopper 5 and the reinforcing plate 19 from rotating. It is possible to suppress rattling. The direction in which the first receiving portion 19b, the bolt hole 19a, and the second convex portion 19c are arranged is not particularly limited, and may be arranged so as to be arranged in a straight line along the vehicle body width direction X, for example. ..

A method for manufacturing the air spring 1 having the above configuration will be described. First, a member in which the support member 6 and the base plate 16 are welded and integrated is inserted into the lower opening 12 of the piston 3 from the support member 6 side, and the upper end portion of the support member 6 protrudes from the upper opening 11 of the piston 3. In this state, the base plate 16 is welded to the inner wall of the bottom of the piston 3 all around to form a piston unit 21 in which the support member 6 and the piston 3 are integrated.

By fitting the upper end of the piston 3 of the piston unit 21 into the lower opening of the flexible member 4 and bolting the lower sheet 13, the lower bead portion of the flexible member is formed by the flange 13a of the lower sheet and the flat surface portion 3c of the piston. 4b can be airtightly sandwiched. When bolting the lower sheet 13, the diameter of the upper end portion of the support member 6 is smaller than the diameter of the upper opening 11, so that the bolt tightening work is not hindered.

The piston unit 21 is elastic in a state where the lower bead portion 4b of the flexible member is fastened to the piston 3 and the flexible member 4 is pushed down as a whole and placed on the reinforcing plate 19 from the upper opening of the flexible member. The stopper 5 is inserted into the flexible member 4 and attached to the pedestal 15, and the elastic stopper 5 is fastened on the pedestal 15. After that, the upper bead portion 4a of the flexible member is sandwiched between the upper plates 2. Thereby, the air spring 1 can be obtained.

As described above, according to the present invention, the support member 6 does not need to be provided with a pedestal portion in the middle as in the conventional case, has a simple structure, and the upper end portion of the support member 6 is opened at the upper end of the piston 3. Since the diameter is smaller than the diameter of 11, the upper end portion of the support member 6 can be projected from the upper opening 11 of the piston 3. Therefore, the elastic stopper 5 can be set at a predetermined position only by attaching the elastic stopper 5 to the upper end of the support member 6 protruding from the piston 3, and an air spring that can be easily assembled can be obtained.

The elastic stopper 5 is attached at a position eccentric from the axial center P of the flexible member 4 and the support member 6, but the upper end surface of the support member 6 is smaller than the upper opening area of the piston 3, and the elastic stopper 5 is viewed in a plan view. It will protrude from the support member 6. Therefore, by reinforcing the elastic stopper 5 with the reinforcing plate 19 having rigidity, it is possible to prevent the elastic stopper 5 from being deformed even if a load is applied to the elastic stopper 5. Thereby, an air spring having excellent durability can be obtained.

In general, it is effective to reduce the rigidity of the vertical spring constant of the air spring in order to improve the riding comfort performance of the vehicle. However, in order to reduce the rigidity of the spring constant, the air spring has a low rigidity. It is necessary to increase the air chamber volume.

In this regard, in the present embodiment, there is a sufficient gap between the upper opening 11 of the piston 3 and the support member 6. Further, an opening 14a is formed in the pipe material 14 of the support member 6. As a result, the internal space of the piston 3 and the internal space of the pipe material 14 can be used as the air chamber volume, and the spring characteristics of the air spring can be adjusted in a wide range.

FIG. 6 is a schematic view showing a main part of a low-floor bus equipped with an air spring 1. As shown in the figure, an upper connecting member 24 for connecting the upper plate 2 and the vehicle body 23 is provided on the lower surface of the tire house portion of the vehicle body 23, and a lower connection for connecting the piston 3 and the axle 25 is provided on the axle 25. A member 26 is provided. The air spring 1 is interposed between the upper connecting member 24 and the lower connecting member 26.

Specifically, a bolt 27 that protrudes downward is fixed to the base plate 16 welded to the piston 3, and this bolt 27 is inserted into a bolt hole (not shown) formed in the lower member 26, and the piston is used with a nut. 3 is attached to the lower connecting member 26. The bolt 10 of the upper plate 2 is inserted into a bolt hole (not shown) formed in the upper connecting member 24, and the upper plate 2 is attached to the upper connecting member 24 by a nut.

In a low-floor vehicle such as a low-floor bus (which may be a railroad vehicle or a truck), the vehicle body 23 rolls around the rolling axis A shown in FIG. FIG. 7 shows the trajectory of the relative displacement between the upper plate 2 of the air spring 1 and the piston unit 21 at this time. As shown in the figure, the piston unit 21 is displaced in the direction of the inner side X2 in the vehicle body width direction with respect to the axial center P of the upper plate 2 as it approaches the upper plate 2.

However, in the present invention, the elastic stopper 5 is arranged at a position eccentric to the outer side X1 in the width direction of the vehicle body with respect to the axial center P of the support member 6 (air spring 1), and is notched in the inner side X2 in the width direction of the vehicle body of the elastic portion 18. Since the portion 18a is provided, it is possible to prevent the elastic stopper 5 from interfering with (contacting) the inner wall of the flexible member 4 located on the inner side X2 in the width direction of the vehicle body or the joint portion between the flexible member 4 and the upper plate 2. It will be possible.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention. For example, as a modification, in the present embodiment, the lower bead portion of the flexible member is hermetically sandwiched between the lower seat and the piston, but it may be a self-sealing type. Further, the upper bead portion of the flexible member adopts a type that is airtightly sandwiched between the upper plate and the lower plate, but may be a crimping type using one plate.

Further, in the present embodiment, the shape of the elastic portion is not limited to a substantially rectangular shape in a side view, but may be a trapezoidal shape or a chevron shape.

The constituent elements disclosed in the present embodiment and the above-described modifications can be combined with each other, and by combining them, new technical features can be formed.

1 Air spring 2 Upper plate 3 Piston 3a Outer peripheral surface 3b Shoulder 3c Flat surface 3d Upper surface 4 Flexible member 4a Upper bead 4b Lower bead 5 Elastic stopper 6 Support member 7 Upper plate 8 Lower plate 8a Flange 9 Through hole 10 Bolt 11 Upper opening 12 Lower opening 13 Lower sheet 13a Flange 14 Pipe material 14a Opening 15 Pedestal 16 Base plate 17 Board 17a Bolt hole 17b First convex part 18 Elastic part 18a Notch part 19 Reinforcing plate 19a Bolt hole 19b First receiving part 19c Second convex part 20 Bolt 21 Piston unit 23 Body 24 Upper connecting member 25 Axle 26 Lower connecting member 27 Bolt A Rolling axis

Claims (4)

An upper plate attached to the vehicle body, a tubular piston attached to the axle, a tubular flexible member interposed between the upper plate and the piston, an elastic stopper, and a support member for supporting the elastic stopper. The bottom of the piston is closed by a base plate , the lower end of the support member is fixed on the base plate , and the upper end thereof protrudes from the upper opening of the piston. The upper end portion of the support member is formed to have a diameter smaller than the upper opening diameter, the elastic stopper is placed on a reinforcing plate having rigidity, and both the elastic stopper and the reinforcing plate are viewed in a plan view. An air spring characterized in that it is attached to the support member at a position eccentric from the axial center of the flexible member so as to partially overlap the upper opening edge of the piston. The support member includes a pipe material and a pedestal for attaching an elastic stopper fixed to the upper end of the pipe material, and the pipe material has an opening for communicating inside and outside. The air spring according to 1. The air spring according to claim 1 or 2, wherein the base plate is welded all around the inner wall of the bottom portion of the piston. The method for manufacturing an air spring according to claim 3, wherein the base plate with a support member obtained by welding the support member to the base plate is inserted into the lower opening of the piston from the support member side to support the piston. With the upper end of the member protruding from the upper opening of the piston, the base plate is welded all around to the inner wall of the bottom of the piston to form a piston unit in which the support member and the piston are integrated, and the lower end of the flexible member. After the portion is fastened to the upper end portion of the piston of the piston unit, both of them are attached to the support member at a position eccentric from the axis of the piston in a state where the elastic stopper is placed on the reinforcing plate. How to make a spring.

Images