JP2005207435A - Extended spring structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with unlimited number of coil springs with different length though some coil springs with different length are required. <P>SOLUTION: This extended spring structure has an extended spring S for moderating impact between a cylinder 1 forming a hydraulic shock absorber and a piston rod 2 retractably inserted into the cylinder 1 during the maximum elongation operation in the hydraulic shock absorber. The extended spring S is formed of two coil springs S1 and S2 with the same length or different length disposed in series in the existence of a spring receiver 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an extension spring structure, and more particularly, to an improvement of an extension spring structure that alleviates an impact during a maximum extension operation of a hydraulic shock absorber.

  Various proposals have been made to alleviate the impact of the hydraulic shock absorber during the maximum extension operation. Among them, there is a proposal of an extension spring structure that reduces the impact by the spring force when the extension spring contracts. For example, in the place disclosed in Patent Document 1, the extension spring is composed of a single coil spring housed in a hydraulic shock absorber.

  In this extended spring structure, for example, the shaft sealing member side in which the end of the coil spring, for example, the upper end closes the opening end of the cylinder constituting the hydraulic shock absorber and allows the piston rod to pass through the shaft core portion. The other end, which is the lower end, is held by the spring receiving member held by the intermediate shaft portion of the piston rod.

Therefore, in this extension spring structure, the extension spring is greatly contracted during the maximum extension operation of the hydraulic shock absorber in which the piston rod protrudes greatly from the inside of the cylinder. The impact between the piston rod and the piston rod can be reduced.
Japanese Patent Laid-Open No. 7-243468 (paragraphs 0003, 0004, 0005, FIG. 1 in the specification)

  However, in the extension spring structure disclosed in Patent Document 1 described above, there is a problem that it is necessary to prepare a variety of extension springs for each hydraulic shock absorber, that is, coil springs having different lengths.

  In other words, hydraulic shock absorbers usually have different characteristics depending on the application, etc. Therefore, even in the case of a coil spring used for an extended spring structure, it is prepared that the wire diameter and winding diameter vary. Of course, there will be preparations that vary in length.

  As a result, in the coil spring used when realizing the extended spring structure, it is necessary to prepare coil springs having various lengths even if only the length is viewed.

  The present invention was created in view of such a current situation, and the object of the present invention is to prepare coil springs having different lengths to a certain extent. As a result, it is possible to contribute to a reduction in the product cost of the hydraulic shock absorber, and to provide an extension spring structure that is optimal for expecting an improvement in versatility of the hydraulic shock absorber. That is.

  In order to achieve the above-described object, the structure of the extended spring structure according to the present invention is the same as that of the first aspect of the present invention. In an extension spring structure having an extension spring that relieves an impact between the piston rod inserted into the piston rod, the extension spring is formed by combining two coil springs having the same length or different lengths. Suppose that they are connected in series.

  Therefore, in the invention of claim 1, in addition to the two patterns each using two types of coil springs having different lengths, two coil springs having different lengths are used in series. Each pattern when two coil springs of the same length are used in series can be realized, and these four patterns are prepared by comparing with a setting using a single coil spring having a different length. The number of types of coil springs can be reduced.

  Therefore, although it is necessary to prepare coil springs having different lengths to some extent, it is not necessary to prepare coil springs having different lengths indefinitely, and as a result, it is possible to contribute to a reduction in product cost in the hydraulic shock absorber. It is optimal for expecting improvement in versatility of the hydraulic shock absorber.

  In the following, the present invention will be described based on the illustrated embodiment. The extended spring structure according to the present invention is embodied in, for example, a single-cylinder hydraulic shock absorber as shown in FIG. In the hydraulic shock absorber, there is an extension spring S that alleviates the impact expressed between the cylinder 1 and the piston rod 2 at the time of the maximum extension operation in which the piston rod 2 projects greatly from the cylinder 1. Become.

  Incidentally, the purpose of the present invention is to provide the extension spring S so that it is sufficient to prepare as few coil springs of different lengths as possible. Of course, when the hydraulic shock absorber is changed to a single-cylinder type, a double-cylinder type may be used instead of the single-cylinder type shown in the drawing.

  At this time, the extension spring S is accommodated in the hydraulic shock absorber while being interposed on the outer periphery of the intermediate shaft portion of the piston rod 2 existing in the cylinder 1, and the upper end thereof is the cylinder. 1 is engaged with an upper spring receiver 4 that is engaged with a lower end of a sealing member 3 that is a shaft sealing member that penetrates the piston rod 2 through the shaft core portion while sealing the opening end portion of the piston rod 2. It is assumed that it is carried by the lower spring receiver 6 carried by the stopper member 5 held in a fixed state on the outer circumference of the shaft portion of the piston rod 2 that is present in the intermediate shaft portion, that is, in the cylinder 1.

  By the way, in the present invention, the extension spring S includes a pair of one coil spring S1 that is upper in the figure and the other coil spring S2 that is lower in the figure. Are arranged in series via a mating spring support 7.

  At this time, the coil springs S1 and S2 may of course have different wire diameters and winding numbers, but when only the length is taken without being concerned with the wire diameter or winding number, the two coil springs having different lengths are used. In addition, the lengths may be the same, and the combination is arbitrary.

  Therefore, in the present invention, by preparing two types of coil springs having different lengths, two coil springs having different lengths are used in series in addition to two patterns that are used independently. In this case, it is possible to embody each pattern when two coil springs having the same length are used in series.

  As a result, the types of coil springs to be prepared can be reduced compared to the case of using a single coil spring having a different length for each of the four patterns, and a coil spring having a somewhat different length is prepared. In other words, it is not necessary to prepare coil springs of different lengths.

  On the other hand, the mating spring receiver 7 is composed of two spring receiving members 71 and 72 formed in the same shape. In the figure, the two spring receiving members 71 and 72 are so-called back-to-back and have an axial core. It is assumed that the piston rod 2 is penetrated through the part.

  At this time, in the present invention, the mating spring receiver 7 is formed by integrating two spring receiving members 71 and 72 by appropriate means. In the place shown in FIG. The two spring receiving members 71 and 72 are integrated.

  At this time, the pin 73 is press-fitted into the open insertion holes (not shown) in the spring receiving members 71 and 72, and therefore the two spring receiving members 71 and 72 are integrated by the pin 73. Of course, when the extension spring S according to the present invention is housed in the cylinder 1, it is possible to avoid in advance the inconvenience that the two spring receiving members 71 and 72 are separated and cannot be integrated. Become.

  In addition, as will be described later, when the two coil springs S1 and S2 are integrally connected by being fitted to the mating spring receiver 7, the integrated mating spring receiver 7 Thus, the two coil springs S1 and S2 are unified, and an advantage of facilitating the collection work of the extension spring S into the cylinder 1 is produced.

  In view of the above, in the present invention, in order to form the mating spring receiver 7, the two spring receiver members 71 and 72 are integrated as long as the function of the extension spring S is not impaired. Although the configuration can be selected, for example, in the case shown in FIG. 3, the joining of the two spring receiving members 71 and 72 is based on a so-called joint joint structure. This is advantageous in that no other parts are required.

  At this time, as shown in the figure, the projections 71a and 72a formed on the spring receiving members 71 and 72 are fitted in holes (not shown) formed on the other party, but the point is that Of course, any structure may be selected as long as is practiced.

  4, a holder member 74 having a caulking structure is interposed on the outer periphery of the mating spring receiver 7. In this embodiment, the spring receiver members 71 and 72 can be easily formed. It becomes advantageous in becoming.

  In the case of this embodiment, it is preferable that the outer periphery of the holder member 74 is directly slidably contacted with the inner periphery of the cylinder 1 so that the mating spring receiver 7 does not roll in the cylinder 1. Therefore, it is advantageous in that the extension spring S is hardly buckled.

  Incidentally, at this time, the holder member 74 is formed of a material having excellent lubricity to reduce the sliding resistance with respect to the inner periphery of the cylinder 1, or the outer periphery is treated with a material having excellent lubricity and the cylinder 1 is processed. It is preferable to reduce the sliding resistance with respect to the inner periphery of the.

  However, from the viewpoint of reducing the sliding resistance with respect to the cylinder 1, although not shown, the mating spring receiver 7, that is, the two spring bearing members 71 and 72 are previously formed of a material having excellent lubricity, and this mating spring. The outer periphery of the receiver 7 may be brought into sliding contact with the inner periphery of the cylinder 1.

1 is a partial front view of a hydraulic shock absorber embodying an extended spring structure according to the present invention, partially broken away. It is a fragmentary longitudinal cross-section which shows one Embodiment of the combined spring receiving member which connects an upper and lower coil spring in a semi-cylindrical state. It is a figure which shows other embodiment of a combination spring receiving member similarly to FIG. It is a fragmentary longitudinal cross-section which shows the mating spring receiving member by other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston rod 7 Matching spring receiver 71,72 Spring receiving member S Extension spring S1, S2 Coil spring

Claims (4)

In an extension spring structure having an extension spring that relieves an impact between a cylinder that forms the hydraulic shock absorber and a piston rod that is removably inserted into the cylinder during the maximum extension operation of the hydraulic shock absorber. An extension spring structure characterized in that two extension springs having the same length or different lengths are arranged in series in the presence of a combined spring receiver. 2. The extended spring structure according to claim 1, wherein the extended spring is interposed on the outer periphery of the intermediate shaft portion of the piston rod existing in the cylinder. The extension spring structure according to claim 1, wherein two spring support members having matching spring receivers formed in the same shape are connected by an appropriate means. The extended spring structure according to claim 1, wherein the outer periphery of the mating spring receiver is slidably contacted with the inner periphery of the cylinder directly or under the intervention of another member.

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