JP2009162265A - Air spring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air spring further improved by maintaining the fitting and connection of a cylindrical film and a piston without releasing the fitting and connection and preventing the impairment of the easy assembling of a bead on the piston side and the piston even if a strong tensile force is applied in addition to a compressive force. <P>SOLUTION: The air spring is provided with the rubber cylindrical film 3, an upper plate 1 airtightly jointed to the upper end of the cylindrical film, and the piston 2 airtightly jointed to the lower end of the cylindrical film 3, and a peripheral face 2B capable of rollingly guiding a turnover cylindrical portion 3D formed by folding back the lower end side accompanied by the elastic deformation of the cylindrical film is formed on the piston 2. The air spring is detachably provided with a press member 4B capable of pressing and sandwiching the whole portion or the approximately whole portion of the piston side bead 3C of the cylindrical film 3 in the width direction with respect to the cylindrical film expanding/contracting movement direction in cooperation with a rim 10 of the piston 2 in which the piston side bead is dropped. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air spring mainly used as a suspension device for trucks and buses. More specifically, the present invention relates to a cylindrical film made of an elastic material and a large-diameter plate-like member hermetically joined to one end in the axial direction thereof. And a piston that is airtightly joined to the other end portion in the axial direction of the cylindrical membrane, and can roll and guide the inverted cylindrical portion formed by folding the other end side with the elastic deformation of the cylindrical membrane. The present invention relates to an air spring having a peripheral surface formed on a piston.

  As this type of air spring, one disclosed in Japanese Patent Application Laid-Open No. 10-325434 is known. As shown in FIG. 3 and the like, a large-diameter plate member (reference numeral 20) and a lower part thereof are provided. It consists of the piston (code | symbol 40) which is located, and the rubber-made cylindrical film | membrane (code | symbol 10) constructed ranging over both. The upper end bead part (reference numeral 16) of the cylindrical rubber film and the large-diameter plate member, and the lower end bead part (reference numeral 30) of the cylindrical rubber film and the piston are fitted and connected in an airtight manner. . For example, when an air spring is used as a suspension device for a truck, a large-diameter plate member is attached to the body frame, and a piston is attached to a suspension arm that supports the wheels.

  The air spring as described above uses Boyle's law. When a person or a load is loaded, the air spring is compressed and the repulsive force is increased. When the air spring is lowered, the original repulsive force is restored. Therefore, it is possible to set a considerably soft spring rate in normal times, and even when it is loaded, no matter how much it is compressed, gas does not disappear and a stronger repulsive force can be obtained, so a good ride comfort and toughness that does not easily bottom It is possible to use as an excellent suspension device having both of the above. In addition, it can attenuate fine vibrations that cannot be absorbed by metal springs such as coil springs, and has the advantage of being able to arbitrarily set the spring rate and vehicle height by changing the amount of air. It is mainly used for buses and trucks. Has been.

  An air spring used as a suspension device for trucks and buses is often subjected not only to a force in a simple expansion / contraction direction but also torsional or torsional force. That is, as disclosed in Patent Document 2 (see FIGS. 3, 5, 6 and the like) and Patent Document 3 (see FIG. 1 (b) and the like), it receives a compression load while being twisted, or is compressed or stretched while swinging. It is a movement to be forced.

  Although not shown in the drawings, in a large truck having two front and rear rear axles with tires on the left and right, a part of the non-driving shaft (dead axle) is lifted to prevent a decrease in ground load when empty. An air spring may also be used as an air bag for an “airlift axle”. In this case, as a means for lifting the non-driving shaft, a means is used in which the cylindrical rubber film is extended as much as possible by supplying air to the air spring (see FIG. 6).

  As described above, in addition to expansion and contraction, in addition to expansion and contraction, the cylindrical membrane is often subjected to a combined force of twisting, twisting, swinging, and the like. Are required to be firmly and airtightly fitted. For this reason, the piston and the lower end bead portion of the tubular membrane are not simply tightly fitted, but are forcedly attached so as not to come off, that is, as shown in FIG. ) And the structure that presses the upper inner peripheral edge of the lower end bead portion has been devised so as to be able to resist a certain amount of force in the tensile direction. The same is true of the structure shown in FIG.

However, due to the increase in suspension stroke and load due to the recent increase in size and speed, the tensile force from the piston of the tubular membrane due to twisting, twisting, or air bag also tends to further increase. There is a possibility that it will come off with the retaining restricting means while considering the ease of attachment, and there remains room for improvement in the fitting connection structure between the tubular membrane and the piston.
JP-A-10-325434 JP 2006-118560 A JP 2006-300236 A

  The purpose of the present invention is to maintain the fitting connection between the tubular membrane and the piston without detachment even if a strong tensile force acts in addition to the original compressive force, An object of the present invention is to provide an air spring that can be further improved without compromising the ease of assembly with the piston.

The invention according to claim 1 includes a cylindrical membrane 3 made of an elastic material, a large-diameter plate-like member 1 hermetically joined to one end of the axial center P direction thereof, and the axial center P direction of the cylindrical membrane 3 A peripheral surface 2B having a piston 2 hermetically joined to the other end of the tube, and capable of rolling and guiding an inverted tube portion 3D formed by folding the other end side with the elastic deformation of the cylindrical film 3. In the air spring formed in the piston 2,
The piston-side bead portion 3C of the tubular membrane 3 is pressed over all or almost all of the width direction with respect to the tubular membrane expansion / contraction movement direction in cooperation with the rim portion 10 of the piston 2 in which the piston-side bead portion 3C is dropped. The holding member 4B that can be clamped is detachably provided.

  The invention according to claim 2 is characterized in that, in the air spring according to claim 1, an end 23 facing the piston-side bead portion of the pressing member 4B is rounded.

  According to a third aspect of the present invention, in the air spring according to the first or second aspect, the stopper main body 4A made of an elastic material is used to restrict a relative approaching movement between the large-diameter plate-like member 1 and the piston 2 beyond a predetermined value. And a hard plate 4B that supports the stopper 4 is fixed to the piston 2 using screwing means 16, and the presser member is constituted by the hard plate 4B. is there.

  According to a fourth aspect of the present invention, in the air spring according to any one of the first to third aspects, an outer peripheral portion 18 for pressing the piston side bead portion 3C of the pressing member 4B is attached to the piston 2. It is formed in the uneven | corrugated shape displaced in the cylindrical film expansion-contraction movement direction with respect to the stop main body 17.

  According to the first aspect of the present invention, since the pressing member and the rim portion are configured to press and hold the piston side bead portion over the entire width or almost the entire width, compared to the conventional structure in which only the inner peripheral end is pressed, the piston side The bead portion can be locked and maintained on the rim portion more firmly. Therefore, even if the cylindrical film is strongly pulled in the direction in which the large-diameter plate-like member and the piston are separated from each other, the dropout (extraction) of the piston-side bead portion from the rim portion is avoided. Since the presser member for that purpose is detachably provided, it is possible to easily attach and detach the piston-side bead portion to the rim portion by removing the presser member. In addition to the fact that a strong tensile force may be applied, the fitting connection between the tubular membrane and the piston is maintained without being disengaged, and the ease of assembly between the piston bead and the piston is impaired. It is possible to provide a further improved air spring.

  According to the second aspect of the present invention, when the cylindrical film is strongly pulled as described above, the end facing the bead portion on the piston side is rounded even if the end face of the holding member is strongly pressed. Therefore, the cylindrical membrane and the presser member are maintained in a surface contact state, and the load per unit area is clearly larger than in the past (contact state with a sharp press surface, etc.). There is an advantage that the risk of inconvenience such as cracking can be avoided.

  According to the invention of claim 3, although described in detail in the section of the embodiment, in order to prevent overcompression and damage of the air spring, a stopper fixed to the piston by screwing means such as a bolt, that is, made of an elastic material. This is a means for combining the hard plate supporting the stopper main body with the pressing member. According to this, since the pressing member is also constituted by the hard plate which is a constituent element of the stopper that is originally provided, the weight reduction and cost reduction by combining the parts can be achieved, and the invention according to the invention of claim 1 or 2 It is possible to provide a more rational air spring that is effective.

  According to invention of Claim 4, since the outer peripheral part which presses a piston side bead part is not only a flat plate but the unevenness | corrugation is given, intensity | strength and rigidity are improved from the shape surface, For example, a hard board is used. In the flat plate state, the strength becomes insufficient, and a press member having a necessary and sufficient strength can be realized by press forming using a steel plate. Therefore, an inexpensive and easy-to-purchase steel plate is possible, and an air spring capable of improving productivity and further reducing costs can be provided.

  Embodiments of an air spring according to the present invention will be described below with reference to the drawings. 1 is a sectional view of an air spring according to the first embodiment, FIG. 2 is a plan view of a single stopper, FIG. 3 is a sectional view of the compressed air spring, and FIGS. 4 and 5 are enlarged views of a fitting portion of a small-diameter bead portion. FIG. 6 is a cross-sectional view illustrating a state in which the small-diameter bead portion is detached when a conventional air spring is pulled.

[Example 1]
The air spring A according to the first embodiment is used as a suspension device for trucks and buses, and as shown in FIGS. 1 and 2, an upper plate (an example of a large-diameter plate member) fixed to a vehicle body frame or the like. ) 1, a piston 2 fixed to a member on the wheel side, a rubber (an example of an elastic material) 3 (an example of an elastic material) 3 laid across both 1 and 2, The stopper 4 is mounted and fixed on the upper wall 2A.

  The diaphragm 3 is a vertical cylindrical rubber having a vertical axis P to form a side wall portion 3A of the air spring portion S which is an internal space (a space surrounded by the upper plate 1, the diaphragm 3 and the piston 2). The upper large-diameter bead portion 3B that is locked and fixed to the upper plate 1 in a close fitting state, the lower small-diameter bead portion 3C that is locked and fixed to the upper portion of the piston 2 in a close-fitting state, and the outer periphery of the piston 2 It has a folded portion (an example of an inverted tube portion) 3D that is rolled and guided by the wall 2B. Each of the large and small bead portions 3B and 3C requiring strength is set to be thick, and a reinforcing member such as a steel wire is often embedded therein.

  The upper plate 1 is a side on which the upper-diameter bead portion 3B and the upper-side plate 1A having a guide outer peripheral portion 1g having a stepped lower section are fitted over the upper portion of the diaphragm 3 including the large-diameter bead portion 3B. The lower plate 1 </ b> B having the peripheral wall 1 a and the lower peripheral wall 1 b at the outer peripheral portion is vertically overlapped and integrated. The supply / discharge pipe 5 for supplying / exhausting air to / from the air spring portion S is welded and fixed in an airtight state penetrating vertically at a position close to the outer periphery of the upper plate 1. The lower end opening forms the supply / exhaust port 6. Reference numeral 7 denotes a fixing bolt for attachment to a frame bracket (not shown).

  The piston 2 includes an outer peripheral wall 2B having a hem-spreading portion 2b at the lower portion, an upper wall 2A, a bottom wall 2C, and a reinforcing member 2D that is installed over the upper wall 2A and the bottom wall 2C. It is composed of a folded cylindrical rubber film. The upper wall 2A is formed between the outer upper wall part 8, the inner upper wall part 9, and the inner and outer upper wall parts 9 and 8 following the upper end part of the outer peripheral wall 2B. It has a reinforcing plate 11 which is composed of a circumferential rim portion 10 to be laminated and which is laminated on the inner upper wall portion 9. The outer peripheral wall 2B functions as a peripheral surface (circumferential surface) capable of rolling and guiding the folded portion 3D, which is an inverted tube portion formed by folding the lower end side with the elastic deformation of the diaphragm 1.

  A center hole 12 that penetrates the inner upper wall portion 9 and the reinforcing plate 11 is formed in the upper wall 2 </ b> A of the piston 2. The bottom wall 2C is formed using a plate material different from the plate material forming the outer peripheral wall 2B and the upper wall 2A, and includes a plurality of mounting bolts 13 protruding downward. The cylindrical reinforcing member 2D is installed and fixed between the lower surface of the reinforcing plate 11 and the upper surface of the bottom wall 2C, and a notch 14 is formed at the upper end portion thereof to communicate the inside and the outside.

  As shown in FIGS. 1 and 2, the stopper 4 includes a stopper body 4 </ b> A made of rubber (an example of an elastic material) and a substrate (an example of a hard plate) 4 </ b> B made of a steel plate for reinforcing and supporting the same. (By vulcanization adhesion or the like), interferes with the supply / exhaust port 6 in the direction of the axis P, and covers the entire upper plate 1, specifically the lower plate 1B. It is formed into a large diameter with a large area. This stopper 4 uses a total of three bolts 16 arranged in three holes 15 formed at equal angles (120 degrees) about the longitudinal axis P on the stopper body 4A, and the piston upper wall It is screwed to 2A.

  The substrate 4B includes a central disc-shaped receiving body 17 that is superimposed on the upper wall 2A, and a presser peripheral portion (an example of the outer peripheral portion) that is formed by bending downward so as to enter the rim portion 10 from the outer peripheral portion. ) 18 and a sheet metal member. In a state where the stopper 4 is mounted and fixed to the piston 2 by a bolt (an example of a screwing means) 16, the small diameter bead portion 3 </ b> C is compressed in the direction of the axis P by the cooperation of the rim portion 10 and the presser peripheral portion 18. Until it is firmly clamped by the piston 2. The stopper 4 is formed with a central hole 19 that penetrates the stopper body 4A and the substrate 4B. As a result, the air spring portion S communicates with the internal space of the reinforcing member 2D via the center holes 19 and 12 and also communicates with the internal space of the piston 2 via the notch 14.

  The reason for providing the stopper 4 is as follows. In other words, it may be used as an elastic suspension support means when the air height is extracted from the air spring portion S to lower the vehicle height clearly. In addition, when the heavy load is applied and the air is compressed strongly, or the diaphragm is damaged. It is also used as a means for preventing damage caused by the lowering of the upper plate 1 when the air escapes due to, for example, or by colliding with the piston 2. Further, there is an advantage that the suspension can be elastically suspended by the stopper 4 even in the state of the prevention means.

  As shown in FIGS. 1 and 2, even if the upper plate 1 and the piston 2 are moved relatively close to the state in which the stopper 4 is sandwiched between the upper plate 1 and the piston 2, the air can be supplied / discharged from the supply / discharge port 6. The avoidance means K is equipped. That is, the avoiding means K is configured by providing a notch 20 formed to eliminate a portion of the stopper body 4A that interferes with the supply / discharge pipe 5 when viewed in the direction of the axis P. As an example, the notch 20 is concentric with the supply / discharge pipe 5 and is a solid arcuate notch having a sufficient depth d, and the axial center and the hole center 15a of one of the three holes 15 are provided. It is formed at a position on a line segment connecting P.

  That is, as shown in FIG. 3, even if the upper plate 1 is lowered until the stopper 4 is compressed (atrophic state) after the air is completely removed (or removed) from the air spring portion S, The presence of the notch 20 acts so that the elastically deformed stopper body 4A does not reach the supply / exhaust pipe 5 portion, and the communication state between the supply / exhaust port 6 and the air spring portion S is maintained. Therefore, air can be supplied / discharged from the supply / discharge pipe 5 even in a contracted state in which the stopper 4 is strongly compressed up and down, and the upper plate 1 is re-lifted by supplying air to the air spring portion S in preparation for the next run. Operation can be performed without problems.

  2, the stopper 4 is further increased in diameter until the supply / exhaust port 6 fully interferes when viewed in the direction of the axis P, and the notch formed in the outer peripheral portion of the stopper body 4A. Even when 21 (that is, the avoiding means K) is smaller, as shown in the blow-out diagram of FIG. 3, the blockage of the supply / exhaust port 6 by the stopper body 4 </ b> A which has a small communication area but is elastically deformed is avoided, Air supply / discharge to / from the air spring portion S by the supply / discharge pipe 5 is possible.

  Next, the engagement structure of the small diameter bead portion 3C to the piston 2 will be described in detail. As shown in FIGS. 1 and 4, the small diameter bead portion 3 </ b> C, which is the piston side bead portion of the diaphragm 3, is cooperated with the rim portion 10 in which the small diameter bead portion 3 is dropped and arranged in the direction of the longitudinal axis P A pressing member 4B is provided that can be pressed and clamped over all or almost all of the width direction with respect to an example of the movement direction (that is, full width or almost full width). As described above, the pressing member 4B is configured to serve as the stopper 4 substrate. First, the small-diameter bead portion 3C is dropped into the rim portion 10 to be fitted, and then the stopper 4 is bolted to the piston 2. Thus, the small-diameter bead portion 3C is assembled in a fitting and engaging state that is held between the presser peripheral portion 18 and the rim bottom 10a of the rim portion 10 so as to be slightly compressed up and down.

  That is, as shown in FIG. 4, the presser peripheral portion 18 that presses the piston-side bead portion 3 </ b> C in the substrate 4 </ b> B is in the direction of the vertical axis P (cylinder) with respect to a receiving body (an example of a stopper body) 4 </ b> A attached to the piston 2. It is formed in a concavo-convex shape bent by press molding so as to be displaced downward in an example of the direction of expansion and contraction of the film-like film. In addition, the outer peripheral end of the presser peripheral portion 18 is formed in a vertical wall flange 22 bent upward. Between the presser peripheral portion 18 and the vertical wall flange 22, there is a bent R portion (“piston side bead portion”). An example) 23 ”is attached. That is, the end of the substrate 4B facing the piston-side bead portion 3C is rounded, and the strength and rigidity of the presser peripheral portion 18 are increased.

  For example, as shown in FIG. 6, the substrate 4 </ b> B of the stopper 4 is set to have a presser peripheral portion 18 that is slightly hung on the inner peripheral side end of the small-diameter bead portion 3 </ b> C (a little overlap in the radial direction). In the conventional air spring A, when the air spring portion S is fully supplied with air using the supply / exhaust pipe 5 to be used as a wheel lift airbag, the lowermost end of the diaphragm 3 (the right side in FIG. 6). In this case, the presser peripheral portion 18 is bent upward by a strong tensile force, and the small diameter bead portion 3 </ b> C has only come out of the rim portion 10 (it sometimes comes out). In addition, since the end face of the outer peripheral end of the substrate 2B in the press-released state tends to be sharp, there is a possibility that a crack is generated from a portion that strongly contacts the outer peripheral end by pulling in the small diameter bead portion 3C.

  On the other hand, as shown in FIGS. 1 and 4, the substrate 4 </ b> B of the stopper 4 whose strength and rigidity of the presser peripheral portion 18 are increased by press-bending is configured so that the radial width of the small-diameter bead portion 3 </ b> C is pressed from above with almost the entire width. In the air spring A of the present invention, although not shown, even if the diaphragm 3 may be strongly pulled in the direction in which the upper plate 1 and the piston 2 are separated from each other, the presser peripheral portion 18 and the rim portion 10 have a small diameter. The bead portion 3 </ b> C is firmly locked, so that the extraction from the rim portion 10 is completely avoided. Further, even if the substrate 4B is strongly pressed at that time, the surface contact state of the bent R portion 23 between the presser peripheral portion 18 and the vertical wall flange 22 is maintained, and damage such as cracking is generated. The fear is also avoided. In addition, if the stopper 4 is removed from the piston 2 by operating the bolt 16, the upper presser of the small diameter bead portion 3C is eliminated, and the small diameter bead portion 3C can be easily attached to and detached from the rim portion 10.

  As shown in phantom lines in FIG. 4, the position of the inclined outer peripheral surface 24 of the stopper body 4A is reduced so that it does not cover the entire presser peripheral portion 18 but rises from the base portion thereof. Even with the stopper 4 having the stopper body 4A, the above-described advantages can be obtained in the same manner. This is because the effect of preventing the small-diameter bead portion 3C from being pulled out from the rim portion 10 is realized by the strength of the substrate 4B. For reference, FIG. 5 shows an example of the configuration dimensions in the vicinity of the small diameter bead portion 3C.

[Another Example]
The presser member 4B has a substrate made of a cast material (cast iron, wrought iron, cast aluminum alloy, etc.) integrally having a presser peripheral portion 18, a thickness is increased to increase strength and rigidity, and the outer peripheral end is rounded. A single plate-like one may be used. In short, the piston-side bead portion 3C may be configured to be able to press and hold over the entire width in the width direction with respect to the tubular film expansion / contraction movement direction or substantially the entire width. The “tubular film expansion / contraction movement direction” includes not only the axis P direction but also the axis direction of the upper plate 1 and the axis direction of the piston 2 (the expansion / contraction movement direction of the diaphragm 3).

Sectional drawing which shows the air spring by Example 1 Plan view of a single stopper in the air spring of FIG. Cross section of compressed air spring Enlarged view of the main part of the piston-side fitting part of the diaphragm Enlarged view with example dimensions of each part in Fig. 4 Sectional view when tension is applied to a conventional air spring

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Large diameter plate-shaped member 2 Piston 2B Perimeter surface 3 Cylindrical membrane 3C Piston side bead part 3D Reversed cylinder part 4A Stopper main body 4B Pressing member, hard board 10 Rim part 16 Screwing means 17 Receiving main body 18 Outer peripheral part 23 Pressing member The end P facing the bead on the piston side

Claims (4)

A cylindrical membrane made of an elastic material, a large-diameter plate-like member hermetically bonded to one end portion in the axial direction of the cylindrical membrane, and a piston hermetically bonded to the other end portion in the axial direction of the cylindrical membrane. An air spring formed on the piston with a circumferential surface capable of rolling and guiding an inverted tube portion formed by folding the other end side with the elastic deformation of the cylindrical membrane,
A presser capable of pressing and clamping the piston-side bead portion of the tubular membrane over all or almost the entire width direction with respect to the tubular membrane expansion / contraction movement direction in cooperation with the rim portion of the piston on which the piston is lowered. An air spring in which a member is detachably provided.   The air spring according to claim 1, wherein an end portion of the pressing member facing the piston-side bead portion is rounded.   A stopper comprising a stopper body made of an elastic material and a hard plate that supports the stopper body is fixed to the piston using screwing means so as to restrict relative movement between the large-diameter plate member and the piston more than a predetermined value. The air spring according to claim 1, wherein the pressing member is configured by the hard plate.   The outer peripheral part which presses the said piston side bead part in the said pressing member is formed in the uneven | corrugated shape displaced in a cylindrical film | membrane expansion-contraction movement direction with respect to the receiving main body attached to the said piston. An air spring according to claim 1.

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