JP2007232053A - Vehicular air spring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air spring having easy and inexpensive construction without the need for air-tight joint with welding. <P>SOLUTION: A first bottomed cylinder body (a housing 10) which has a bottom portion on the upper side and opens downward a second bottomed cylinder body (a housing 20) which has a bottom portion on the upper side and opens downward are arranged at a predetermined distance. A diaphragm 30 of a cylindrical elastomer member is used for air-tight joining the opening end on the upper side thereof to the outer peripheral face of the housing 10 and for air-tight joining the opening end on the lower side thereof to the outer peripheral face of the housing 20. The housings 10, 20 and the diaphragm 30 form an air chamber 50 as a sealed space. <P>COPYRIGHT: (C)2007,JPO&INPIT

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.

  4 and 5 show a diaphragm type air spring used for a general automobile suspension, and the outline thereof will be described below. First, as shown in FIG. 4, metal housings 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, the dust cover 700 is attached to form the air spring AS shown in FIG. 5. For example, the housing 100 side is fixed to the vehicle body (not shown), and the housing 200 side is fixed to the 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. And as shown in FIG. 4, the bottom plate 230 is airtightly joined to the inner surface of the housing 200 by welding (W). Thus, the air chamber 500 is a sealed space.

"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-described conventional air spring, as shown in FIG. 4, since the bottom plate 230 is hermetically joined to the housing 200 by welding (W), an accurate welding operation is required. . Further, in order to confirm the airtightness, for example, if 100% inspection is performed by a leak test apparatus using helium gas, it causes a cost increase. Further, by adjusting the capacity of the air chamber 500 in FIG. 4, the spring constant as the air spring can be set to a predetermined value. For this purpose, the welding position of the bottom plate 230 with respect to the housing 200 is accurately managed. In addition, since airtight joining is required, welding work is not easy, which also increases costs.

  Then, this invention makes it a subject to provide the air spring which can be comprised easily and cheaply, without requiring the airtight joining by welding. It is another object of the present invention to easily set a spring constant as an air spring to an arbitrary value with simple means.

  In order to achieve the above object, an air spring according to the present invention includes, as described in claim 1, a first bottomed cylinder that has a bottom at the top and opens downward, and the first bottomed cylinder. A second bottomed cylinder which is arranged at a predetermined distance below the body and has a bottom at the top and which opens downward, and a lower open end is hermetically joined to the outer peripheral surface of the second bottomed cylinder. And a diaphragm of a cylindrical elastic member whose upper opening end is airtightly joined to the outer peripheral surface of the first bottomed cylindrical body, and the bottom of the first bottomed cylindrical body in the diaphragm and the first bottomed cylinder An air chamber is formed between the bottom of the two bottomed cylinders. Note that the upper and lower parts in the present application are relatively specified based on the general arrangement when the air spring is mounted on the vehicle in specifying the relationship between the components, and the upper and lower arrangements are not necessarily limited. It is not limited to.

  In the above-described air spring, as described in claim 2, the air spring includes a cylindrical body that slidably accommodates the opening end side of the second bottomed cylindrical body, and is axially disposed with respect to the cylindrical body. It is preferable that a part of the opening end of the second bottomed cylindrical body is fixed to the inner peripheral surface of the cylindrical body and formed integrally at a predetermined position.

  Furthermore, as defined in claim 3, groove portions formed on the outer peripheral surfaces of the first and second bottomed cylindrical bodies over a predetermined range in the axial direction of the first and second bottomed cylindrical bodies, respectively. The diaphragm was joined to the outer peripheral surfaces of the first and second bottomed cylinders including the groove so that the inner peripheral surfaces of the upper and lower opening end portions were in close contact with each other. It should be.

  And as described in Claim 4, it is good for the bottom part of a said 2nd bottomed cylinder to have a recessed part which bulges below. Further, as described in claim 5, at least a part is fixed to an opening end below the cylindrical body, and a supporting member for supporting the cylindrical body may be provided.

  Since this invention is comprised as mentioned above, there exist the following effects. That is, the air spring configured as described in claim 1 is configured such that the first bottomed cylindrical body and the second bottomed cylindrical body are hermetically joined by the diaphragm of the cylindrical elastic member. And an air chamber is formed between them, and it is not necessary to hermetically join the first bottomed cylindrical body, the second bottomed cylindrical body, and at least one of them with another member by welding. Therefore, the air spring can be configured easily and inexpensively. For example, even when the support member is welded to the second bottomed cylindrical body, it can be easily joined, and it is not necessary to inspect the airtight state of the joint, so that the cost is much higher than that of the conventional device. Go down.

  Furthermore, as described in claim 2, the opening of the second bottomed cylindrical body at a predetermined position in the axial direction with respect to the cylindrical body that slidably accommodates the opening end side of the second bottomed cylindrical body. If a part of the end is fixed to and integrally formed with the inner peripheral surface of the cylinder, the above air can be obtained only by changing the joining position of the opening end of the second bottomed cylinder to the cylinder. Since the capacity of the chamber can be easily adjusted, the spring constant as the air spring can be easily set to an arbitrary value. In this case, when the cylindrical body and the second bottomed cylindrical body are joined, there is no need for airtight joining, so that an arbitrary spring constant can be easily and accurately set.

  In addition, as described in claim 3, it includes grooves formed on the outer peripheral surfaces of the first and second bottomed cylindrical bodies, and the outer peripheral surfaces of the first and second bottomed cylindrical bodies respectively have upper and If the diaphragm is joined so that the inner peripheral surface of the lower opening end portion is in close contact, and tightened by, for example, an annular member, the diaphragm can be reliably airtightly joined to the first and second bottomed cylindrical bodies.

  Furthermore, as described in claim 4, if the concave portion bulging downward is formed at the bottom of the second bottomed cylindrical body, the capacity of the air chamber can be increased, and a large capacity can be obtained. Since it can be ensured, the spring constant as an air spring can be set to a relatively low value with a simple configuration.

  In addition, as described in claim 5, at least a part of the supporting member that supports the cylindrical body may be fixed to the opening end portion below the cylindrical body, and the cylindrical body and the supporting member are hermetically bonded. Since it is not necessary, the cost is 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, a metal housing 10 constituting a first bottomed cylindrical body having a bottom at the top and opening downward, and a second bottomed cylinder having a bottom at the top and opening downward. A metal housing 20 constituting the body is disposed at a predetermined distance. The upper opening end of the cylindrical elastomer member is hermetically joined to the outer peripheral surface of the housing 10, and the lower opening end is hermetically joined to the outer peripheral surface of the housing 20. The housings 10 and 20 and the diaphragm 30 form an air chamber 50 that can be a sealed space. 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 outer peripheral surfaces of the housings 10 and 20, and are fastened by the annular members 41 and 42, respectively, so that the tightly joined state can be maintained. As shown in FIG. 1, the housing 10 is formed in a U-shaped container shape (bottomed cylinder) having a bottom 11 and a body 12. In addition, since the bottom part 11 is located above in FIG. 1 and becomes the top part of the housing 10, it means the bottom part in a bottomed cylindrical body. Further, the housing 10 has a groove 12 a formed on the outer peripheral surface of the body 12.

  On the other hand, as shown in FIG. 1, the housing 20 of the present embodiment is also a bottomed cylindrical body having a bottom portion 21 and a body portion 22, but the body portion 22 is formed in a long shape, and the bottom portion 21 and the body portion 22 are formed. The outer diameters are smaller than the inner diameters of the bottom part 11 and the body part 12, respectively, and are also called pistons. Further, the body portion 22 has a diameter-reduced portion 22s formed at a portion adjacent to the bottom portion 21, and a groove portion 22a is formed on the outer peripheral surface of the reduced-diameter portion 22s. As a support member for supporting the housing 20, a bottom plate 23 is welded (W) to the inner side of the open end of the body portion 22, and a positioning member 62 when fixed to the vehicle is fixed to the bottom plate 23. Has been. It should be noted that the body 22 and the bottom plate 23 do not need to be hermetically joined, and may be in a joined state in which at least a part of the bottom plate 23 is fixed and the housing 20 can be supported via the bottom plate 23. Therefore, the outer peripheral shape of the bottom plate 23 does not necessarily coincide with the inner peripheral shape of the trunk portion 22, and the bottom plate 23 of the present embodiment is formed in an irregular outer peripheral shape. A gap is formed between the inner surface and the inner surface as shown on the right side of FIG.

  As shown in FIG. 1, the housings 10 and 20 formed as described above are arranged so that the inner peripheral surface of the opening end portion above the diaphragm 30 is in close contact with the outer peripheral surface of the trunk portion 12 including the groove portion 12a. The diaphragm 30 is joined to the body 12 of the housing 10 and fastened by the annular member 41. As a result, the upper open end of the diaphragm 30 is hermetically joined to the body 12 of the housing 10. Similarly, the diaphragm 30 has a reduced diameter portion 22s of the housing 20 such that the inner peripheral surface of the opening end portion below the diaphragm 30 is in close contact with the outer peripheral surface of the body portion 22 (the reduced diameter portion 22s) including the groove portion 22a. And are tightened by the annular member 42. As a result, the opening end portion below the diaphragm 30 is hermetically joined to the body portion 22 of the housing 20. As for the joining of the diaphragm 30 and the reduced diameter portion 22s, the lower opening end of the diaphragm 30 is inserted from the bottom 21 side, is attached to the reduced diameter portion 22s beyond the groove 22a, and is tightened by the annular member 42. Then, it is folded back to the state shown in FIG.

  FIG. 2 shows an air spring according to another embodiment of the present invention. A lower housing in the present embodiment has a bottom 21x and a body 22x, and constitutes a second bottomed cylindrical body. It consists of a member 20x and a cylindrical second member 20y that slidably accommodates the opening end side thereof. The bottom portion 21x of the first member 20x is formed in the same shape as the bottom portion 21 of FIG. 1, and the reduced diameter portion 22s is formed on the trunk portion 22x, similarly to the trunk portion 22 of FIG. A groove 22a is formed on the outer peripheral surface of 22s. The first member 20x and the second member 20y are such that the opening end portion below the trunk portion 22x is connected to the second member 20y so that the opening end portion above the second member 20y is positioned in the vicinity of the reduced diameter portion 22s. On the other hand, at a predetermined position in the axial direction (substantially intermediate position in FIG. 2), it is integrally formed by welding (W) to the inner surface of the second member 20y. The welding of the body 22x and the second member 20y need not be airtight. A part of the bottom plate 23 is welded (W) to the inside of the opening end below the second member 20y. In FIG. 2, the same reference numerals as those in FIG. 1 are given to substantially the same components as those shown in FIG.

  Thus, according to the embodiment shown in FIG. 2, the body portion 22x of the first member 20x is welded to the second member 20y at a predetermined position in the axial direction (substantially intermediate position in FIG. 2). Therefore, the capacity of the air chamber 50 can be changed only by changing the welding position. Therefore, for example, if the capacity of the air chamber 50 is relatively small, a relatively high spring constant can be obtained. Thus, since the capacity of the air chamber 50 can be easily adjusted by simple means, the spring constant as the air spring can be easily and accurately set to an arbitrary value. In particular, when the first member 20x and the second member 20y are welded, it is not necessary to perform hermetic joining. Therefore, the first member 20x and the second member 20y can be joined at low cost, and the cost is reduced as compared with the conventional apparatus.

  FIG. 3 shows an air spring according to still another embodiment of the present invention. Instead of the first member 20x shown in FIG. 2, a second bottomed cylindrical body having a bottom 21z and a body 22x is provided. Since the first member 20z is provided and the other constituent elements are substantially the same as those shown in FIG. 2, the same reference numerals as those in FIG. In the embodiment shown in FIG. 3, the bottom 21z of the first member 20z has a recess 21r that bulges downward, and a capacity larger than the capacity of the air chamber 50 in the embodiment of FIG. 2 can be secured. Therefore, an air spring having a lower spring constant than the air spring shown in FIG. 2 can be configured.

  As described above, according to the air spring of each of the above embodiments, the capacity of the air chamber 50 can be easily adjusted by simple means, and the spring constant as the air spring can be set to an arbitrary value. In addition, it can be manufactured at a lower cost than conventional devices. Also, the upper and lower opening ends of the diaphragm 30 can be securely held by the annular members 41 and 42, respectively, and the diaphragm 30 can be prevented 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 shows the air spring which concerns on other embodiment of this invention. It is sectional drawing which shows the air spring which concerns on other embodiment of this invention. It is sectional drawing which shows the conventional air spring. It is a perspective view which shows the external appearance of a general air spring.

Explanation of symbols

10 Housing (first bottomed cylinder)
20 Housing (second bottomed cylinder)
20x first member (second bottomed cylinder)
20y second member (cylinder)
20z 1st member (2nd bottomed cylinder)
11, 21, 21x, 21z Bottom portion 12, 22, 22x Body portion 12a, 22a Groove portion 30 Diaphragm 41, 42 Annular member 50 Air chamber

Claims (5)

  A first bottomed cylinder having a bottom at the top and opening downward; and a second bottomed cylinder that is disposed at a predetermined distance below the first bottomed cylinder and has a bottom at the top and opens downward. The lower opening end is airtightly joined to the outer peripheral surface of the bottom cylindrical body and the second bottomed cylindrical body, and the upper opening end is airtightly joined to the outer peripheral surface of the first bottomed cylindrical body. An air spring comprising a diaphragm of a cylindrical elastic member, wherein an air chamber is formed between a bottom portion of the first bottomed cylindrical body and a bottom portion of the second bottomed cylindrical body in the diaphragm. .   A cylindrical body that slidably accommodates the open end side of the second bottomed cylindrical body, and a part of the open end of the second bottomed cylindrical body at a predetermined position in the axial direction with respect to the cylindrical body The air spring according to claim 1, wherein the air spring is integrally formed by being fixed to an inner peripheral surface of the cylindrical body.   The first and second bottomed cylindrical bodies are provided with grooves formed on the outer peripheral surfaces of the first and second bottomed cylindrical bodies over a predetermined range in the axial direction of the first and second bottomed cylindrical bodies, respectively. 3. The air spring according to claim 2, wherein the diaphragm is joined to the outer peripheral surface of the second bottomed cylindrical body so that the inner peripheral surfaces of the upper and lower opening ends are in close contact with each other.   The air spring according to any one of claims 1 to 3, wherein a bottom portion of the second bottomed cylindrical body has a concave portion that bulges downward. The air spring according to any one of claims 2 to 4, further comprising a support member that is fixed at least partially to an opening end portion below the cylindrical body and supports the cylindrical body.

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