JP5657464B2 - Air spring - Google Patents

Description

  The present invention relates to an air spring that uses an air pressure to support an input load.

  As an air spring used for a vehicle suspension or the like, for example, one described in Patent Document 1 is known. The air spring described in Patent Document 1 includes a chamber connected to a vehicle body support member, a piston connected to the tire support member side, one end and the other end connected to the chamber and the piston, respectively, And a diaphragm forming a chamber. The diaphragm is folded back so as to be inverted inside and outside so that the piston side is inserted into the air chamber.

  In the air spring as described above, when the piston moves in the direction approaching the vehicle body (bound direction) due to the load from the road surface side, the air in the air chamber in the diaphragm is compressed and the air pressure rises. The load input from the side is supported. Further, the piston moves in a direction (rebound direction) in which the piston is separated from the vehicle body by reaction of movement in the bound direction.

  By the way, when the relative movement amount of the piston and the chamber in the rebound direction increases, a tensile force acts on the diaphragm and damages the diaphragm. Therefore, it is necessary to restrict the relative movement of the two at a predetermined position. Normally, the restricting position is set so that the folded portion is arranged below the mounting member for attaching the diaphragm to the piston (on the bottom side of the piston), that is, the outer surface of the piston and the diaphragm are always in contact with each other. (See Patent Document 2).

  However, if the folded portion is disposed below the mounting member, it may be difficult to ensure the relative movement amount of the chamber and the piston, that is, the stroke of the piston.

JP 2006-144940 A JP 2001-65619 A

  The present invention has been made in consideration of the above-described facts, and an object thereof is to provide an air spring that can easily secure a relative movement amount between a chamber member and a piston member.

An air spring according to a first aspect of the present invention is attached to a chamber member attached to a first moving body and a second moving body that moves relative to the first moving body, and is opposed to and spaced apart from the chamber member. A cylindrical piston member having an end mounting portion formed on the chamber member side, and an elastic cylindrical membrane member, one end being attached to the chamber member and the other end being an end of the piston member A diaphragm that is attached to a mounting portion, forms an air chamber between the chamber member and the piston member, and has a folded portion that is folded back so that the piston member side is inserted into the air chamber; and is disposed on the outer periphery of the other end, attached by sandwiching the other end of the diaphragm between the end mounting part, preparative and the outer peripheral surface of the piston member and the outer peripheral surface is flush shape The relative movement of the member and the first moving body and the second moving body in a direction away from each other is such that the folded portion of the diaphragm is closer to the mounting member than the boundary between the mounting member and the outer periphery of the piston member. And a restricting means for restricting the movement to be permitted.

  In the air spring according to the first aspect, when the first moving body and the second moving body move relative to each other, the piston member moves so as to enter the air chamber and approaches the chamber member. Thereby, the air chamber is reduced, the air in the air chamber is compressed and the air pressure rises, and the input load is supported by the air pressure. When the first moving body and the second moving body move relative to each other by the reaction, the piston member moves in a direction away from the chamber member. The restricting means is configured to move the first movable body and the second movable body relative to each other so that the folded portion of the diaphragm is allowed to move to a position that is disposed closer to the mounting member than the boundary between the outer periphery of the mounting member and the piston member. To regulate.

  By setting the restriction position of the relative movement of the first moving body and the second moving body at the restriction member at the above position, the restriction position is more piston than the boundary between the mounting member and the outer periphery of the piston member. Compared with the case where the position is set on the member side, the relative movement amount of the chamber member and the piston member, that is, the stroke of the piston member can be increased. Therefore, the relative movement amount of the chamber member and the piston member can be easily ensured.

  In addition, the folded portion may be disposed closer to the mounting member than the boundary between the outer periphery of the mounting member and the piston member, but the outer peripheral surface of the mounting member and the outer peripheral surface of the piston member are flush with each other. Since no is formed, it is possible to suppress damage to the folded portion due to the boundary portion between the two. Note that the “flat surface” here means a flat state without a step.

  In the air spring according to claim 2, the end attaching portion is configured to have a stepped portion having a smaller diameter than the second moving body side of the piston member and a radially outer corner portion having a curved shape. The end portion disposed at the step portion and facing the step portion has a shape along the curved shape.

  As described above, the end mounting portion of the piston member has a small diameter to form the step portion, and the mounting member is arranged on the step portion so that the outer peripheral surface of the mounting member and the outer peripheral surface of the piston member can be flush with each other. . In addition, the outer circumferential surface of the mounting member and the outer circumferential surface of the piston member are formed by making the radially outer corners of the stepped portion have a curved shape and the end facing the stepped portion of the mounting member is shaped along the curved shape. A smooth continuous surface can be formed by reducing the number of recesses in the boundary portion.

  The air spring according to a third aspect is characterized in that a gap in the cylinder axis direction of the piston member is formed between the mounting member and the stepped portion on a radially inner side.

  In the stepped portion, when the radially outer corner portion is curved and the portion facing the stepped portion of the mounting member is shaped along the curved shape, the mounting member is in the outer peripheral side when the mounting member is in contact with the stepped portion. It is difficult to caulk from the inside to the inner circumference. Therefore, by forming a gap in the cylinder axis direction of the piston member between the mounting member and the stepped portion, the mounting member can be easily caulked from the outer peripheral side to the inner peripheral side.

  As described above, according to the air spring of the present invention, the relative movement amount of the chamber member and the piston member can be easily ensured.

It is side surface sectional drawing which shows the structure of the suspension to which the air spring which concerns on embodiment of this invention was applied, and has shown the state which has a suspension arm in a neutral position. It is a partially expanded view of the air spring of FIG. It is sectional drawing which shows the state which the air spring which concerns on embodiment of this invention moved to the bound direction. It is sectional drawing which shows the state which the air spring which concerns on embodiment of this invention moved to the rebound direction.

  Hereinafter, an air spring according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 schematically shows a suspension to which an air spring according to an embodiment of the present invention is applied. As shown in FIG. 1, the suspension 12 includes an air spring 10 formed in a drum shape as a whole and a suspension arm 14 formed in a beam shape. Cylindrical bush holders 16 and 18 are disposed on the suspension arm 14 at the proximal end and the distal end along the longitudinal direction, respectively.

  The suspension arm 14 has a proximal end side bush holder 16 connected to a vehicle body 15 via a rubber bush (not shown) so as to be swingable, and a distal end side bush holder 18 connected to a wheel via a rubber bush or the like. A hub (not shown) is rotatably connected. As a result, the suspension arm 14 is supported so as to be swingable in the vertical direction with respect to the vehicle body 15 around the bush holder 16 on the base end side.

  As shown in FIG. 1, the air spring 10 is provided with a bracket member 20 formed in a substantially bottomed cylindrical shape with a shallow bottom at a lower end portion thereof. The bracket member 20 is in a state in which the lower surface side thereof is in close contact with the upper surface side of the suspension arm 14 and is fixed to the suspension arm 14 by bolt fastening or the like.

  A piston member 24 is attached to the bracket member 20. The piston member 24 is attached to the suspension arm 14 via the bracket member 20. The piston member 24 is formed in a substantially bottomed cylindrical shape, and an end mounting portion 28 is formed at one end. The end attachment portion 28 has a smaller diameter than the other part of the piston member 24 (the bracket member 20 side from the end attachment portion 28), and a step portion 28D is configured. The corner portion disposed on the radially outer side of the stepped portion 28D has a curved shape (R shape). Hereinafter, this corner is referred to as “R corner 28R”. The other end of the piston member 24 is fixed onto the bottom surface of the bracket member 20.

  The air spring 10 is provided with a cylindrical chamber member 22 at a position facing the piston member 24. The chamber member 22 is closed on the top surface side by a circular top plate portion 23. On the outer periphery of the chamber member 22, a groove 22A is formed over the entire periphery.

  The air spring 10 is provided with a thin cylindrical diaphragm 32 that is connected and fixed to the end mounting portion 28 of the piston member 24 and the outer periphery of the chamber member 22. The diaphragm 32 is formed of a rubber film in which a cord reinforcing layer (not shown) is embedded. An upper connection portion 36 that is externally inserted into the chamber member 22 is formed in a cylindrical shape at the upper end portion of the diaphragm 32, and a lower connection portion 38 that is externally inserted into the end mounting portion 28 of the piston member 24 at the lower end portion. Is configured in a cylindrical shape.

  The diaphragm 32 is connected and fixed so that the upper connecting portion 36 is extrapolated to the chamber member 22 and caulked by the upper caulking ring 42 from the outer peripheral side so as to be airtight with the chamber member 22. Further, the lower connecting portion 38 is extrapolated to the end attaching portion 28 and is caulked from the outer peripheral side by a lower caulking ring 40 as an attaching member, and is connected and fixed so as to be in an airtight state with the piston member 24. As a result, an air chamber 44 is formed on the inner peripheral side of the diaphragm 32. The air chamber 44 is closed at the lower end and the upper end by the piston member 24 and the chamber member 22, respectively.

  As shown in FIG. 2, the lower caulking ring 40 is disposed in the step portion 28D. The thickness of the lower caulking ring 40 in the radial direction is such that the lower caulking ring 40 after caulking is fastened fills the step portion 28D so that the outer circumferential surface of the piston member 24 and the outer circumferential surface of the lower caulking ring 40 are flush with each other. Thickness is assumed. Therefore, there is no step between the outer circumferential surface of the lower caulking ring 40 and the outer circumferential surface of the piston member 24, and the surfaces are flush. A portion of the lower caulking ring 40 facing the R corner portion 28R has a shape along the curved shape of the R corner portion 28R. That is, the lower caulking ring 40 is shaped so that the end facing the R-angled portion 28R is curved so that the angle with the axial direction of the piston member 24 decreases as it goes radially outward. A gap S in the cylinder axis direction of the piston member 24 is formed between the radially inner side of the lower caulking ring 40 and the stepped portion 28D.

  The end attaching portion 28 side of the piston member 24 is inserted into the air chamber 44, and the inner peripheral surface and the outer peripheral surface of the diaphragm 32 are inverted in a U-shape to form a folded portion 34. The position of the folding portion 34 changes as the piston member 24 and the chamber member 22 move relative to each other.

  The chamber member 22 is fixed to a portion of the vehicle body 15 that faces the upper surface side of the suspension arm 14. Thereby, the air spring 10 is interposed between the suspension arm 14 and the vehicle body 15. One end of a pressure pipe 46 is connected to the top plate portion 23 of the chamber member 22. The other end of the pressure pipe 46 is connected to a compressed air supply source (not shown) such as an air pump or an accumulator mounted on the vehicle body 15 side, and the compressed air supply source communicates with the air chamber 44. ing. The pressure air supply source supplies compressed air having an air pressure corresponding to the traveling state of the vehicle and the loaded load into the air chamber 44 through the pressure pipe 46.

  The air spring 10 is provided with a dust cover 50 formed in a substantially cylindrical shape on the outer peripheral side of the diaphragm 32. The dust cover 50 is formed with a cylindrical upper connecting tube portion 54 at the upper end portion, and a shoulder portion 56 that extends obliquely downward from the lower end portion of the upper connecting tube portion 54 is integrally formed. . The shoulder 56 is formed in a tapered shape whose inner and outer diameters gradually increase from the upper end side toward the lower end side. The dust cover 50 is integrally provided with a cylindrical bellows portion 58 that extends downward from the lower end portion of the shoulder portion 56. The bellows portion 58 can be expanded and contracted (stroked) along the swinging direction of the suspension arm 14, and the inner diameter thereof is larger than the outer diameter of the diaphragm 32. On the lower side of the bellows portion 58 of the dust cover 50, a lower connecting cylinder portion 60 is integrally formed.

  The upper connecting cylindrical portion 54 of the dust cover 50 is fastened from the outer peripheral side to the inner peripheral side by the upper binding band 64 and attached to the outer side of the upper caulking ring 42 on the outer periphery of the chamber member 22. The lower connecting cylindrical portion 60 of the dust cover 50 is fastened from the outer peripheral side to the inner peripheral side by the lower binding band 66 and attached to the outer periphery of the bracket member 20.

  Here, the dust cover 50 is blow-molded (blow-molded) using, for example, a polyolefin elastomer that is a resin material having a relatively high flexibility. The molding material for the dust cover 50 may be other resin materials, rubber compositions, or the like as long as it is rich in flexibility and can be blow-molded even if it is not a polyolefin elastomer.

The air spring 10 is provided with restriction means 70 for restricting the relative movement amount of the vehicle body 15 and the suspension arm 14. The restricting means 70 includes a vehicle height sensor 76, an exhaust valve 72, and an air supply valve 74. The vehicle height sensor 76 can detect the height of the vehicle body, and when the vehicle body height (vehicle height) reaches a height at which the vehicle body 15 and the suspension arm 14 move relative to each other beyond a predetermined amount in a direction away from each other. The exhaust signal is output to the exhaust valve 72. When this exhaust signal is input, the exhaust valve 72 is opened, and the relative movement in the direction in which the vehicle body 15 and the suspension arm 14 are separated from each other is restricted by the pressure drop in the air chamber 44. As shown in FIG. 4, the relative movement in the direction in which the vehicle body 15 and the suspension arm 14 are separated from each other is regulated by the boundary portion between the lower caulking ring 40 and the outer peripheral surface of the piston member 24. It is set at a position P1 arranged on the caulking ring 40 side lower than 25. That is, the folded portion 34 is restricted so as to be able to move to the lower caulking ring 40 side beyond the boundary portion 25.
Further, when the vehicle height decreases to a predetermined position, the vehicle height sensor 76 outputs an air supply signal to the air supply valve 74. When this air supply signal is input, the air supply valve 74 is opened, compressed air is supplied into the air chamber 44, and relative movement in the direction in which the vehicle body 15 and the suspension arm 14 approach each other is restricted. Restriction of relative movement in the direction in which the vehicle body 15 and the suspension arm 14 approach each other is set at a position where the folded portion 34 of the diaphragm 32 does not reach the bottom of the piston member 24 as shown in FIG.

  Next, the operation and action of the air spring 10 according to this embodiment configured as described above will be described.

  The air spring 10 according to the present embodiment is interposed between the vehicle body 15 and the suspension arm 14, thereby causing the spring reaction force corresponding to the air pressure in the air chamber 44 to act on the suspension arm 14. The load input to the suspension arm 14 from the road surface side is supported by the spring reaction force.

  That is, as shown in FIG. 3, when the suspension arm 14 swings to the vehicle body side (bound direction X) due to a load from the road surface side, the air in the air chamber 44 is compressed by the piston member 24 and the air pressure rises. This air pressure supports a load input from the road surface side via the suspension arm 14. When the movement in the bound direction X exceeds a predetermined amount, an air supply signal is output from the vehicle height sensor 76 to the air supply valve 74, and the air supply valve 74 is opened. Thereby, compressed air is supplied into the air chamber 44, the air pressure in the air chamber 44 increases, and relative movement in the direction in which the vehicle body 15 and the suspension arm 14 approach each other is restricted.

  Subsequently, as shown in FIG. 4, the suspension arm 14 swings in the direction away from the vehicle body (rebound direction Y) by the reaction. When the movement in the rebound direction Y exceeds a predetermined amount, an exhaust signal is output from the vehicle height sensor 76 to the exhaust valve 72, and the exhaust valve 72 is opened. As a result, the pressure in the air chamber 44 decreases, and relative movement in the direction in which the vehicle body 15 and the suspension arm 14 are separated from each other is restricted.

  In the air spring 10 of the present embodiment, the restriction of the relative movement in the direction in which the vehicle body 15 and the suspension arm 14 are separated from each other in the rebound direction by the restriction means 70 is such that the folded portion 34 of the diaphragm 32 is below the boundary portion 25. The position P1 is set at the caulking ring 40 side. Accordingly, the relative movement amount of the chamber member 22 and the piston member 24 can be increased as compared with the case where the folded portion 34 of the diaphragm 32 is disposed on the piston member 24 side with respect to the boundary portion 25.

  In the air spring 10 of the present embodiment, the folded portion 34 of the diaphragm 32 may be disposed on the lower caulking ring 40 side over the boundary portion 25, but the outer periphery of the lower caulking ring 40 and the piston member 24 may be disposed. Since the surface is flush with the surface, even when the folded portion 34 is pressed against the boundary portion 25, the damage to the folded portion 34 is suppressed as compared with the case where a step is formed. can do.

  In the air spring 10 of the present embodiment, the radially outer side of the stepped portion 28D is a curved R corner portion 28R, and the portion facing the R corner portion 28R of the lower caulking ring 40 is the R corner portion 28R. Although it is a shape along the curved shape, the corner portion does not necessarily have an R shape in this way, and may be a corner portion that is not chamfered. As in the present embodiment, by using the R corner portion 28R, the concave portion in the boundary portion 25 between the outer peripheral surface of the lower caulking ring 40 and the outer peripheral surface of the piston member 24 is reduced, thereby forming a smooth continuous surface. be able to. Thereby, the damage by the folding | returning part 34 being pressed on the boundary part 25 can be suppressed more.

Moreover, in the air spring 10 of this embodiment, the clearance gap S is comprised between the radial direction inner side of the lower caulking ring 40, and the level | step-difference part 28D. Although the gap S is not an essential configuration, if the lower caulking ring 40 is brought into contact with the stepped portion 28D before caulking, the portion along the R corner portion 28R particularly hits the R corner portion 28R to the inside in the radial direction. It becomes difficult to crimp. Therefore, before caulking, the lower caulking ring 40 can be easily caulked radially inward by separating the lower caulking ring 40 and the stepped portion 28D from each other. After caulking, a gap S in the cylinder axis direction of the piston member 24 is formed between the radially inner side of the lower caulking ring 40 and the stepped portion 28D as in the present embodiment.
In addition, after caulking, the lower caulking ring 40 may sandwich the diaphragm 32 between the piston member 24 on the radially inner circumferential surface, and may be separated from the entire stepped portion 28D.

10 Air spring 14 Suspension arm (second moving body)
15 Body (first moving body)
22 Chamber member 24 Piston member 25 Boundary portion 28 End mounting portion 28D Step portion 28R R Corner portion 32 Diaphragm 34 Folding portion 40 Lower caulking ring 70 Restricting means S Clearance X Bound direction Y Rebound direction

Claims (3)

A chamber member attached to the first moving body;
A cylindrical piston member attached to a second moving body that moves relative to the first moving body, and arranged to face and separate from the chamber member, and having an end mounting portion on the chamber member side; ,
It is a cylindrical membrane having elasticity, one end is attached to the chamber member, the other end is attached to an end attachment portion of the piston member, and an air chamber is formed between the chamber member and the piston member, A diaphragm configured of a folded portion folded so that the piston member side is inserted into the air chamber;
An attachment member disposed on an outer periphery of the other end of the diaphragm, attached with the other end of the diaphragm sandwiched between the end attaching portion, and an outer peripheral surface and the outer peripheral surface of the piston member being flush with each other; ,
The first movable body and the second movable body are moved relative to each other in the direction in which the first movable body and the second movable body are separated from each other. Regulation means to regulate to allow,
With air spring. The end mounting portion is configured to be a stepped portion having a smaller diameter than the second moving body side of the piston member and having a radially outer corner portion curved.
2. The air spring according to claim 1, wherein the attachment member is disposed at the stepped portion, and an end portion facing the stepped portion has a shape along the curved shape.   The air spring according to claim 2, wherein the mounting member forms a gap in the cylinder axis direction of the piston member between the mounting member and the stepped portion on a radially inner side.

Images