JPS62167943A - Pneumatic spring - Google Patents

Abstract

PURPOSE:To make it possible to increase or decrease the spring constant of a pneumatic spring in a smooth and continuous manner, by changing the piston diameter under the operation of a fluid expansion/contraction means so as to constantly and surely obtain the effective diameter. CONSTITUTION:The opening of a hydraulic passage 6 is made at one or plural places on the outer surface of a contracted part 4. The pressure oil, which is supplied to or discharged from the hydraulic passage 6, goes into or comes out of a space 7, which is partitioned by an outer surface 4a of the contracted part 4 and an inner surface 5a of a flexible membrane 5. Accordingly, when the pressure oil is completely discharged from the space 7, the effective diameter of a pneumatic spring becomes D0, a minimum value, while, when the space 7 is filled with the pressure oil, the effective diameter becomes D1, a maximum value. Thus, the spring constant can be increased or decreased in a smooth and continuous manner.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in an air spring that is applied to, for example, automobiles, moving vehicle bodies, railway vehicles, and other vehicles to exhibit vibration-proofing and buffering functions.

(Prior Art) An end plate, a piston spaced apart from and concentric with the end plate, and a cylindrical flexible membrane whose end portions are hermetically connected to the piston and the end plate. Conventional air springs of this type include the so-called bellows type and the diaphragm type, and in these air springs, the diameter of the piston is changed appropriately in the length direction.
The spring constant characteristics of the air spring can be made non-linear depending on the amount of deflection.

(Problem to be Solved by the Invention) However, in such a conventional air spring, since the piston shape is always constant, when the air spring is applied to an automobile body, for example, the vehicle height of the automobile is When a specific constant value is reached, the air spring always has a constant spring constant, and therefore, there is a problem in that it is not possible to select the ride comfort of the vehicle depending on the road surface on which the vehicle is traveling. .

For this reason, such a conventional air spring can be adjusted to a specific vehicle height by connecting it to an auxiliary tank via an air passage and selectively communicating or breaking communication between the auxiliary tank and the air spring. A proposal has been made to make it possible to select two types of spring constants for air springs as required.

However, according to this proposed technology, in order for the auxiliary tank to fully demonstrate its original function, its volume is relatively large, so a sufficiently large occupied space is required for the installation of the air spring. There is a problem, and moreover,
In this proposed technique, since only one of two types of spring constants can be selected, there is another problem that the degree of freedom in selecting the spring constant is low.

The present invention advantageously solves these problems by providing an air spring whose spring constant can be changed steplessly without increasing the occupied space.

(Means for Solving the Problems) The air spring of the present invention is provided with fluid expansion and contraction means for steplessly changing the diameter of the piston, particularly in the piston portion that comes into contact with the cylindrical flexible membrane.

(Function) In this air spring, by appropriately changing the piston diameter under the action of the fluid expansion/contraction means that expands and contracts depending on the amount of fluid supplied, the air spring can be adjusted as desired. The effective diameter can always be ensured, and therefore the spring constant of the air spring can be increased or decreased steplessly with a simple and compact structure.

In other words, if the piston diameter is gradually increased to increase the effective diameter of the air spring, then the gradual increase in the spring constant is
Conversely, decreasing the piston diameter results in a gradual decrease in the spring constant.

(Example) The present invention will be explained below based on illustrated examples.

FIG. 1 is a sectional view showing an embodiment of the present invention, in which 1 represents an end plate, 2 represents a piston spaced apart from the end plate 1 and concentric with it, and 3 represents an end plate. The figure shows a cylindrical flexible membrane whose upper and lower end portions are caulked and fixed to an end plate 1 and a piston 2, respectively.

Here, the part of the piston 2 that contacts the cylindrical flexible membrane body 3,
That is, in the diagram of the piston 2 with respect to the end plate 1, when the piston 2 is vertically displaced relative to the end plate 1, the cylindrical flexible membrane body 3
A constricted portion 4 is formed in the portion that contacts with the constricted portion 4, and a flexible membrane 5 as an example of a fluid expansion/contraction means that can be mainly composed of rubber, rubber-like elastic material, etc. is provided on the outer periphery of the constricted portion 4.
Attach liquid-tightly by gluing, caulking, etc. Therefore, here, the constricted portion 4 of the piston 2 is covered over its entire length by the flexible membrane 5, which also has a cylindrical shape.

Further, here, a hydraulic passage 6 connected to a hydraulic pressure supply/discharge source (not shown) is formed in the piston, and this hydraulic passage 6 is opened at one or more places on the outer surface of the constricted portion 4. Therefore, the hydraulic pressure supplied to and discharged from the hydraulic passage 6 can flow into and out of the space 7 defined by the outer circumferential surface 4a of the constricted portion 4 and the inner circumferential surface 5a of the flexible membrane 5. As shown in FIG. 1(a), when the pressure oil is discharged from the space 7, the diameter of the constricted portion 4 is reduced, and pressure oil is supplied into the space 7 as shown in FIG. 1(b). When this occurs, the diameter of the constricted portion 4 is increased.

Therefore, when the pressure oil is completely discharged from the space 7, the effective diameter of the air spring becomes the minimum value D0, and when it is filled with pressure oil, the effective diameter becomes the maximum value.

As described above, since the air spring of the present invention can be constructed in a sufficiently small size, it hardly increases the occupied space (
, it can be installed at the required location, and by supplying pressure oil to the space 7, the piston diameter as desired, in other words, the desired effective diameter of the air spring can be easily and quickly adjusted. can bring. Note that if the effective diameter of the air spring is reduced, for example to obtain a low spring constant, it is expressed as W = PXA W: Support load P: Air spring internal pressure A: Effective area (-02) Since the load supporting capacity of the air spring also decreases, in order to keep the supporting load W of the air spring constant,
It is necessary to increase the internal pressure of the air spring sufficiently to compensate for the reduction in the effective diameter and therefore the effective area as well as the increase in the air volume within the air spring.

Figures 2 and 3 show air springs in which the flexible membrane 5 is folded inward at its lower and upper ends and fixed to the constricted portion 4, respectively, for the purpose of increasing the amount of change in the piston diameter. In these air springs, the deflection margin of the flexible membrane 5 is considerably larger than that in the above-mentioned example, so that the maximum value of the piston diameter can be made sufficiently large.

In addition, in the air spring described above, the cylindrical flexible membrane body 3
When each end portion of the Sequentially performing the positioning and caulking of the caulking ring 8.9 with respect to the end portion causes an increase in the number of man-hours required for attaching the cylindrical flexible membrane body 3, so it is preferable to perform the caulking process as shown in FIG. The caulking ring 8.9 is adhered in advance to a predetermined position of the cylindrical flexible membrane body 3 by vulcanization or other means, thereby positioning the caulking ring 8.9 with respect to the end portion of the cylindrical flexible membrane body 3. Make work unnecessary.

Here, as shown in FIG. 5(a), a caulking ring 9 is attached to the outer peripheral surface of the large diameter end portion of the cylindrical flexible membrane body 3, and a caulking ring 9 is attached to the inner peripheral surface of the small diameter end portion. When the stepped sleeves 10 are positioned and fixed, as shown in FIG. 5(b), the stepped sleeve lO is fitted onto the piston 2 via the O-ring 11, and
is removed using a snap ring or other retaining ring 12, and the caulking ring 9 is caulked to the end plate 1 while the flexible membrane body 3 is folded back, thereby forming a cylindrical flexible body. The membrane body 3 can be attached more easily.

FIG. 6 shows another example in which the cylindrical flexible membrane body 3 is not only attached but also easily removed for purposes such as repair and replacement. A male screw member 13 with a flange is positioned and fixed on the outer peripheral surface of the large diameter end portion, and a disk-shaped plate 14 for airtightly closing the flexible membrane 3 is positioned and fixed on the small diameter end portion. Here, the disk-shaped plate 14 is attached to the piston 2.
By fitting the male screw member 13 into the female screw portion 1a provided on the end plate 1 via the O-ring 15, the cylindrical flexible membrane body 3 can be attached extremely easily. Moreover, the flexible membrane body 3 can be easily removed by performing the operations opposite to these.

Note that the cross-sectional shape of the disk-shaped plate 14 that closes one end of the cylindrical flexible membrane body 3 can be changed as appropriate to a channel shape as shown in FIG. 6(C) or other shapes.

Moreover, FIG. 7 shows still another example of installation,
In this example, a ring 16 with a flange is provided on the outer peripheral surface of the large diameter end portion of the cylindrical flexible membrane body 3, and a ring 16 with a flange is provided on the inner peripheral surface of the small diameter end portion, similar to that shown in FIG. Stepped sleeve 1
Fix 0 respectively.

Here, the small diameter side end portion of the flexible membrane body 3 is attached to the piston 2 in the same manner as described in FIG.
6, a fixing ring 1 having a substantially channel-shaped cross section;
The cylindrical flexible membrane body 3 is attached by connecting it to the flange portion 1b of the end plate 1 by means 7.

Here, as the fixing ring 17, for example, FIG.
), one end of each of the two semicircular arc members 17a, 17a is hinged to each other, and the other end is attached to one of the arc members 17a, for example. The provided elastic claw piece 17b and the other arc-shaped member 17
It is possible to use a sawtooth-like structure provided in a, which can be mutually detachable in cooperation with the recess 17c. In addition, in order to sufficiently ensure airtightness between the flange portion 1b and the ring 16 with such a fixing ring 17, the seventh
As shown in Figure (bl), when the two are in surface contact via the O-ring, both flanges are provided with inclined surfaces that gradually become thinner from the outer surface side in the radial direction outward, and fixed. Preferably, the ring 17 is also provided with an inclined surface corresponding to those inclined surfaces.

On the other hand, as shown in FIG.
If this is secured by the O-ring 18 interposed between the two, it is not necessary to form the slope as described above.

This invention has been explained above based on the illustrated examples.
In the embodiment shown in the figures, the fluid expansion/contraction means attached to the constriction of the piston may be a cylindrical ring-shaped body or the like having a floating ring shape, and in such a case, the fluid expansion/contraction means may be
It becomes unnecessary to consider the airtightness of the part fixed to the piston.

(Effects of the Invention) Therefore, according to the present invention, it is possible to change the piston diameter and the effective diameter of the air spring steplessly and quickly with a simple and compact structure. A spring constant can always be realized.

[Brief Description of the Drawings] Figures 1 to 3 are cross-sectional views showing embodiments of the present invention, Figure 4 is a cross-sectional view showing how the caulking ring is fixed to the cylindrical flexible membrane body, and Figures 5 to 7. The figures are views showing other examples of attachment of the cylindrical flexible membrane body. ■... End plate 2... Piston 3...
Cylindrical flexible membrane body 4... Narrow portion 5... Flexible membrane
6...Hydraulic passage 7...Space
8.9...Caulking ring patent applicant Brideston Co., Ltd. Kaki 1 Tomb N Prisoner 2 (a) (b) Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. An end plate, a piston spaced apart from and concentric with the end plate, and a cylindrical flexible membrane whose end portions are hermetically connected to the piston and the end plate. An air spring comprising: a fluid expansion/contraction means for steplessly changing the diameter of the piston at a portion of the piston that contacts the cylindrical flexible membrane body.