JP4767038B2 - Air spring - Google Patents

Description

  The present invention relates to an air spring, and more particularly to an air spring used for a suspension of a vehicle.

  Air springs are already used in automobiles and railway vehicles, and generally air is sealed in bellows or diaphragm containers. And air springs of various structures such as those for controlling the introduction and discharge of air from the outside are known. For example, the following Non-Patent Document 1 discloses a bellows type, a diaphragm type, a composite type, and the like, and further discloses an air suspension strut in which an air spring is attached to a shock absorber.

  FIG. 5 to FIG. 7 show a diaphragm type air spring used for a general automobile suspension, and its outline will be described below. First, as shown in FIG. 5, a metal housing 100 and 200 having cylindrical body parts and a diaphragm 300 of a cylindrical elastomer member joined to the opening ends of these body parts are provided. The air chamber 500 is formed and sealed with air. Further, a dust cover 700 is attached to form the air spring AS shown in FIG. 7, and for example, the housing 100 side is fixed to a vehicle body (not shown), and the housing 200 side is fixed to a lower arm (not shown).

  In the above-described conventional air spring, the opening ends of the diaphragm 300 are joined to the openings of the housings 100 and 200, and are fastened by annular members 410 and 420 called caulking rings, respectively, so that the joined state can be maintained. It is configured. As shown in FIG. 5, the housing 100 is formed in a U-shaped cross section having a top part 110 and a body part 120, and as shown in FIG. 6, an annular recess 121 is formed on the outer peripheral surface of the body part 120 and A plurality of grooves (typically indicated by 122) are formed on the bottom surface of the recess 121. As a result, an annular engagement end 123 is formed at the opening end of the body 120. Thus, when the annular member 410 is mounted at a position facing the annular recess 121, the diaphragm 300 is prevented from falling off by the engagement end portion 123.

"Automotive Technology Handbook" 2nd volume, design edition, Japan Society for Automotive Engineers, June 15, 1992, 1st edition, 2nd edition, 462 pages to 463 pages and 468 pages

  In the above conventional air spring, as shown in FIG. 6, the body 120 of the housing 100 is formed with an annular recess 121 and a plurality of grooves 122 on the outer peripheral surface thereof. In order to ensure the rigidity, the plate thickness is inevitably increased. In particular, the annular recess 121 requires a plate thickness Dy that can satisfy the rigidity. In order to prevent the diaphragm 300 from falling off, the engagement end 123 formed at the opening end of the body 120 is required to have a predetermined height or more with respect to the annular recess 121. Accordingly, the general surface and the top portion 110 of the body portion 120 have a plate thickness Dx larger than the plate thickness Dy. As a result, not only the increase in mass and cost of the housings 100 and 200 are unavoidable, but also the cutting for forming the annular recess 121 and the plurality of grooves 122 is complicated, which causes a cost increase. The top portion 110 may also have the plate thickness Dy. However, when the housings 100 and 200 are formed from a metal flat plate having a predetermined thickness by drawing using a press device, for example, the top portion 110 is set to the plate thickness Dy. It is necessary to partially change the press load for forming the top portion 110, and the plate thickness adjustment is not easy, but the cost increases. Furthermore, since the portion indicated by Dz in FIG. 6 is cut off, the material yield decreases accordingly.

  Therefore, an object of the present invention is to provide an air spring that can reliably hold the diaphragm in the housing and can reduce the mass and cost of the housing.

In order to achieve the above object, an air spring according to the present invention includes a housing having at least a cylindrical body part and a cylindrical diaphragm joined to an opening end of the body part. In the air spring for enclosing air in the diaphragm, the housing extends to the outside in the radial direction from the outer peripheral surface of the body portion adjacent to the groove portion and the groove portion formed on the outer peripheral surface of the body portion. An annular extending portion formed at the opening end of the body portion, and the body portion with respect to a press-formed product having a cross-sectional hat shape having a flange portion integrally with the opening end of the body portion. A portion extending from the outer peripheral surface of the diaphragm to the flange portion is cut to form the annular extending portion, and the diaphragm has an inner peripheral surface in close contact with the outer peripheral surface of the body portion including the groove portion. To the housing It is obtained by and.

Since this invention is comprised as mentioned above, there exist the following effects. That is, in the air spring configured as described in claim 1, a groove portion formed on the outer peripheral surface of the trunk portion, and adjacent to the groove portion, extends radially outward from the outer peripheral surface of the trunk portion. The housing is provided with an annular extending portion formed at the opening end of the body portion, and the diaphragm is joined to the outer peripheral surface of the body portion including the groove portion so that the inner peripheral surface of the diaphragm is in close contact with the housing. As a result, the thickness of the housing can be reduced while ensuring a structure that can securely hold the diaphragm in the housing, and the mass can be reduced and the cost can be reduced. Further, the housing has an annular extension by cutting a portion extending from the outer peripheral surface of the barrel portion to the flange portion in a hat-shaped press-formed product having a flange portion integrally and continuously with the opening end of the barrel portion. Since the portion is formed, the structure can be easily processed, and the cost can be further reduced.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an air spring according to an embodiment of the present invention, which is used for an automobile suspension. As shown in FIG. 1, metal housings 10 and 20 having cylindrical body portions and a diaphragm 30 of a cylindrical elastomer member joined to the opening ends of these body portions are provided, and the housings 10 and 20 and the diaphragm 30 are provided. The air chamber 50 that can be a sealed space is formed by the annular members 41 and 42, respectively. In addition, an intake / exhaust port 61 is attached to the housing 10 so that air is sucked into and exhausted into the air chamber 50 via the intake / exhaust port 61. Although not shown in the present embodiment, an air spring is configured by mounting a dust cover similar to the dust cover 700 shown in FIG.

  In the present embodiment, the opening ends of the diaphragm 30 are joined to the openings of the housings 10 and 20, and are held by the annular members 41 and 42, respectively, so that the joined state can be maintained. As shown in FIGS. 1 and 2, the housing 10 is formed in a container shape having a U-shaped cross section having a top portion 11 and a body portion 12. Further, as shown in FIG. 2, the housing 10 has a groove 12 a formed on the outer peripheral surface of the body portion 12, and an opening end of the body portion 12 adjacent to the groove portion 12 a from the outer peripheral surface of the body portion 12. An annular extension 12b is formed so as to extend outward in the radial direction. In addition, the formation method of these groove part 12a and the cyclic | annular extension part 12b is mentioned later.

  On the other hand, as shown in FIG. 1, the housing 20 of this embodiment has a long cylindrical body 21 and a short cylindrical body 22 joined together and a bottom plate 23 joined together. It is formed in a shape and is also called a piston. In other words, the housing 20 has a shape similar to that in which a large-diameter opening is formed at the center of the top portion 11 of the housing 10 and has a shape in which an annular flange portion 22c is formed around the opening. Therefore, as shown in FIG. 3, the body part 22 is formed with an S-shaped cross section on both sides, and a groove part 22 a is formed on the outer peripheral surface of the body part 22 as described above, and at the opening end of the body part 22. An annular extending portion 22b is formed so as to extend radially outward from the outer peripheral surface of the body portion 22.

  Further, as shown in FIG. 1, an annular flange portion 21 c is also formed around one opening of the trunk portion 21 constituting the housing 20, and this flange portion 21 c is welded to the flange portion 22 c of the trunk portion 22 ( W) is airtightly joined. Further, a bottom plate 23 is hermetically joined to the other opening of the body portion 21 by welding (W). In the present embodiment, as shown in FIG. 1, an annular step portion is formed on the outer side in the radial direction of the body portion 22 on the flange portion 21c. The method of forming the groove 22a and the annular extension 22b is the same as that of the groove 12a and the annular extension 12b, which will be described later. Note that a positioning member 62 is fixed to the bottom plate 23 of the housing 20 when mounted on the vehicle.

  As shown in FIG. 1, the diaphragm 30 is joined to the body 12 of the housing 10 so that the inner surface of one opening end of the diaphragm 30 is in close contact with the outer surface of the body 12 including the groove 12 a. And tightened by the annular member 41. Thereby, one opening end part of the diaphragm 30 is airtightly joined to the trunk | drum 12 of the housing 10, and is reliably hold | maintained by the cyclic | annular extension part 12b. Similarly, the diaphragm 30 is joined to the body 22 of the housing 20 so that the inner peripheral surface of the other opening end of the diaphragm 30 is in close contact with the outer surface of the body 22 including the groove 22a. Tightened. As a result, the other opening end of the diaphragm 30 is hermetically joined to the body 22 of the housing 20 and is securely held by the annular extension 22b. Thus, the annular extension portions 12b and 22b can reliably prevent the diaphragm 30 from falling off. As for the joining of the diaphragm 30 and the body part 22, the other opening end of the diaphragm 30 is inserted from the annular extension part 22b side, is attached to the body part 22 beyond the groove part 22a, and is tightened by the annular member 42. Then, it is folded back to the state shown in FIG.

  Here, the formation method of the groove part 12a and the cyclic | annular extension part 12b in the trunk | drum 12 of the housing 10 is demonstrated. First, as shown in FIG. 2, the housing 10 is formed in a shape having a flange portion 12 d (indicated by a two-dot chain line in FIG. 2) integrally with the opening end of the body portion 12, and has a hat-shaped cross section. It is a press-formed product. Next, the press-formed product is cut to form a groove portion 12a radially inward from the outer peripheral surface of the body portion 12, and the flange portion 12d from the outer peripheral surface of the body portion 12 adjacent to the groove portion 12a. The portion extending to is cut, and an annular extending portion 12 b is formed at the opening end of the body portion 12. In this case, the annular extending portion 12b is formed to extend radially outward from the outer peripheral surface of the body portion 12 by a distance d.

  Similarly, first, as shown in FIG. 3, the body portion 22 of the housing 20 is formed in a cross-sectional hat shape having a flange portion 22d (indicated by a two-dot chain line in FIG. 3) integrally with the opening end. Is done. Next, a groove 22a is formed on the outer peripheral surface of the body portion 22 by cutting, and a curved corner from the outer peripheral surface of the body portion 22 adjacent to the groove portion 22a to the flange portion 22d is cut. An annular extension 22 b is formed at the open end of 22. Also in this case, the annular extending portion 22b is formed to extend radially outward from the outer peripheral surface of the body portion 22 by a distance d.

  The manufacturing method of an air spring is demonstrated in order of a process including the formation process of the said groove part and an annular extension part. First, a metal flat plate (not shown) is drawn by a progressive press device (not shown), and processed into a shape including the housing 10 as described above. That is, the housing 10 having a hat-shaped cross section having the body 12 and the flange 12d is continuously formed. In this case, the flange portion 12d is continuously formed as a so-called progressive flange. Next, the outer side of the annular extending portion 12b includes a part of a curved corner portion extending from the body portion 12 to the flange portion 12d by the punching process and extends radially outward from the body portion 12 by a distance d. Cut along the contour to form a housing 10 having a hat-shaped cross section. Subsequently, the groove portion 12a is formed on the outer peripheral surface of the body portion 12 by cutting, and the inner side of the annular extending portion 12b is cut linearly to form an obtuse corner portion as shown in FIG.

  Similarly to the above, the body portion 22 in the housing 20 is formed as shown in FIG. 3, and then the body portion 22 is welded to the body portion 21 to form the housing 20. Then, as shown in FIG. 1, the diaphragm 30 is attached so that the inner peripheral surface of one opening end of the diaphragm 30 is in close contact with the outer peripheral surface of the body portion 12, and tightened by the annular member 41. Similarly, the diaphragm 30 is mounted so that the inner peripheral surface of the other opening end of the diaphragm 30 is in close contact with the outer peripheral surface of the body portion 22, and tightened by the annular member 42. As a result, both open end portions of the diaphragm 30 are securely held by the body portions 12 and 22 of the housings 10 and 20, respectively.

  FIG. 4 shows a part of an air spring according to another embodiment of the present invention. The body 22 constituting the housing 20 of the present embodiment and a bottom 24 formed integrally therewith are shown in FIG. The housing 10 is formed in a similar shape. Since the air chamber 50 is defined by the bottom portion 24 and the air tightness in the air chamber 50 is maintained, the bottom portion 24 is not welded to the flange portion 21c of the body portion 21 without performing airtight joining (W ). Therefore, in this embodiment, as shown in FIG. 4, the bottom plate 25 is joined to the other opening of the body portion 21 by welding (W), but the bottom plate 25 is provided with a communication hole 25 a. The body portion 21 communicates with the atmosphere.

  As described above, according to the air spring of each of the above-described embodiments, both opening end portions of the diaphragm 30 can be securely held in the body portions 12 and 22 of the housings 10 and 20, respectively, and the annular extension portion 12b. And 22b can reliably prevent the diaphragm 30 from falling off. Note that the above air spring can be mounted on a shock absorber (not shown) and applied to an air suspension strut.

It is sectional drawing which shows the air spring which concerns on one Embodiment of this invention. It is sectional drawing which expands and shows a part of one housing with which it uses for the air spring of one Embodiment of this invention. It is sectional drawing which expands and shows a part of other housing provided to the air spring of one Embodiment of this invention. It is sectional drawing which shows a part of air spring which concerns on other embodiment of this invention. It is sectional drawing which shows the conventional air spring. It is sectional drawing which expands and shows a part of housing provided for the conventional air spring. It is a perspective view which shows the external appearance of a general air spring.

Explanation of symbols

10, 20 Housing 12, 22 Body 12a, 22a Groove 12b, 22b Annular extension 30 Diaphragm 41, 42 Annular member 50 Air chamber

Claims (1)

An air spring comprising at least a housing having a cylindrical body and a cylindrical diaphragm joined to an opening end of the body, wherein the housing is disposed on an outer peripheral surface of the body. comprises a formed groove, and said body portion annular extending portion formed on the open end of such adjacent the groove portion extending radially outward from the outer peripheral surface of the barrel, the barrel For a press-molded product having a hat-shaped cross section that has a flange portion integrally with the open end, a portion extending from the outer peripheral surface of the barrel portion to the flange portion is cut to form the annular extension portion. the body portion of the outer peripheral surface, the air spring, characterized in that the diaphragm as the inner peripheral surface of the diaphragm are in close contact formed by joining to the housing containing the groove.

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