JP2008196629A - Air spring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air spring having a high degree of flexibility in design of an orifice and taking measures to prevent generation of high frequency sound. <P>SOLUTION: This air spring 1 is provided with: an air spring body 2 with a body air chamber 2a formed in its inside and filled with pressurized air and with elastic force adjusted by pressure of the pressurized air; and an auxiliary tank 10 having an auxiliary air chamber 10a formed in its inside. A handling screw hole 7 and the orifice 31 are formed in the base plate 4 of the air spring body 2, and the body air chamber 2a and auxiliary air chamber 10a are communicated with each other through the orifice 31. The orifice 31 is arranged in a position offset from the handling screw hole 7 formed in the base plate 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air spring that is suitable for use in vibration suppression of railway vehicles and the like.

  As disclosed in Patent Document 1, an air spring is used to suppress vibration of a railway vehicle or the like. One conventional example of this type of air spring is shown in FIGS.

  8 and 9, an air spring 100 includes an air spring main body 101 in which pressurized air is filled in an internal main body side air chamber 101 a and the elasticity is adjusted by the pressure of the pressurized air, and the air spring main body 101. An auxiliary tank 102 disposed below and having an auxiliary air chamber 102a therein, and a rubber spring portion 103 interposed between the air spring main body 101 and the auxiliary tank 102, both the air spring main body 101 and the auxiliary tank 102 are provided. The main body side air chamber 101 a and the auxiliary air chamber 102 a are communicated with each other via the communication path 104.

  The air spring main body 101 includes a pair of base plates 110 and 111 arranged in the vertical position, and a bellows body 112 fixed so as to surround the pair of base plates 110 and 111. The lower base plate 111 is provided with a handling screw hole 113 at its center position. A handling member (not shown) that has entered the handling screw hole 113 from above is fixed by screwing so that handling such as transportation of an air spring can be easily performed.

  The communication path 104 includes an orifice 114 provided in the lower base plate 111, a through hole 115 penetrating the center position of the rubber spring portion 103, and a boss portion 116 projecting downward from the bottom plate 105 of the rubber spring portion 103. It is composed of

  The orifice 114 is provided on the lower surface of the handling screw hole 113 of the lower base plate 111, that is, at the same position as the handling screw hole 113.

  In the above configuration, when the air in the air spring main body 101 is compressed (pressurized) and expanded (depressurized) by the vibration of the railway vehicle, the main body side air chamber 101a of the air spring main body 101 and the auxiliary air chamber 102a of the auxiliary tank 102 are used. Both air flows out and in through the communication path 104 due to the differential pressure therebetween. A damping force is obtained by friction and diffusion generated when the air flow passes through the orifice 114 of the communication path 104.

The damping effect by the orifice 114 is more effective when the hole area is smaller and the hole length is shorter. Therefore, the conventional configuration in which the handling screw hole 113 and the orifice 114 of the base plate 111 are provided side by side is inevitably shortened in the hole length of the orifice 114, and thus is effective in terms of an attenuation effect. Further, the configuration of the conventional example in which the handling screw hole 113 and the orifice 114 are in the same position is excellent in the workability of the base plate 111.
JP 2005-231464 A

  However, it has been found that when the hole length of the orifice 114 is short, high-frequency sound (so-called whistling sound) is generated. In recent years, there is a high demand for quietness of vehicles, and it is necessary to prevent generation of annoying high-frequency sound from the air spring 100.

  Here, it is conceivable to prevent the generation of high-frequency sound by devising the hole shape of the orifice 114. However, in the above-described conventional example, the orifice 114 is disposed at the same position as the handling screw hole 113. The design freedom of 114 is very low, and it is not possible to take measures to prevent the generation of high-frequency sound (flute sound).

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide an air spring that has a high degree of freedom in designing an orifice and can take measures to prevent annoying high-frequency sound from occurring. .

  The present invention has the following features. First, the invention according to the first feature of the present invention is an air spring in which a main body side air chamber is formed, the main body side air chamber is filled with pressurized air, and the elasticity is adjusted by the pressure of the pressurized air. An air spring comprising: a main body; an auxiliary tank having an auxiliary air chamber therein; a handling screw hole in a base plate of the air spring main body; and an orifice communicating the main body side air chamber and the auxiliary air chamber. In summary, the orifice is provided at a position offset with respect to the handling screw hole of the base plate.

  According to such a feature, since the entire length of the base plate can be set to the length of the orifice without being restricted by the handling screw hole, the degree of freedom in designing the orifice is increased, and the high-frequency sound is increased. It can be set as the form which can suppress.

  The gist of another feature of the invention is that the inner peripheral surface of the orifice is formed as a diameter-expanded surface that expands toward both ends.

  According to this feature, since the air flow passing through the orifice smoothly flows in the vicinity of the entrance / exit of the orifice by the enlarged diameter surface, generation of high-frequency sound due to turbulent air flow can be suppressed. In other words, conventionally, when the air flow passes through the orifice, it hits the corner of the inlet / outlet of the orifice to cause turbulence, and this turbulence generates high-frequency sound (so-called whistling sound). Since it can suppress, generation | occurrence | production of a high frequency sound can be suppressed.

  The gist of the invention relating to other features is that the expanded surface is an arc surface.

  In another aspect of the invention, the radius of curvature R of the expanded surface is in the range of (1/3) · t ≦ R ≦ (1/2) · t, where t is the thickness of the base plate. The gist.

  According to such a feature, the central portion of the orifice can maintain the minimum diameter, and thus the generation of high-frequency sound can be prevented while maintaining the attenuation characteristics.

  According to the present invention, it is possible to provide an air spring that has a high degree of freedom in the design of an orifice and can take measures to prevent the generation of high-frequency sound.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 5 show an embodiment of the present invention, FIG. 1 is a sectional view of an air spring, FIG. 2 is a plan view of a lower base plate, FIG. 3 is a sectional view taken along line AA in FIG. Is an enlarged cross-sectional view of the vicinity of the orifice of the base plate, FIG. 5A is a diagram showing an experimental result of the high-frequency sound generation state in the conventional example, and FIG. 5B is an experimental result of the high-frequency sound generation state in this embodiment. FIG.

  As shown in FIG. 1, the air spring 1 includes an air spring main body 2 in which an internal main body-side air chamber 2 a is filled with pressurized air, and the elasticity is adjusted by the pressure of the pressurized air. An auxiliary tank 10 that is disposed below and has an auxiliary air chamber 10a therein and a rubber spring portion 20 interposed between the air spring body 2 and the auxiliary tank 10 are provided. The inside of both is communicated via the communication path 30.

  The air spring main body 2 includes a pair of base plates 3 and 4 arranged in the vertical position, and a bellows body 5 fixed so as to surround the pair of base plates 3 and 4. A side air chamber 2a is formed. The upper base plate 3 is provided with an air supply unit 6 for supplying air to the main body side air chamber 2a at the center position. The lower base plate 4 is provided with a bottomed handling screw hole 7 at its center position. A handling member (not shown) that has entered into the handling screw hole 7 from the upper air supply unit 6 is fixed by screwing so that handling such as transportation of an air spring can be easily performed.

  The rubber spring portion 20 includes an upper surface plate 21, a lower surface plate 22, and a plurality of elastic members 23 and rigid members 24 that are alternately stacked therebetween. The upper surface plate 21 is fixed to the base plate 4 below the air spring body 2 by a bolt fastening portion 25. A pipe portion 26 projects downward from the bottom plate 22 at the center position.

  The communication passage 30 includes an orifice 31 provided in the lower base plate 4, a through hole 32 that penetrates the center position of the rubber spring portion 20, and a pipe passage 33 in the pipe portion 26 of the rubber spring portion 20. .

  As shown in FIGS. 2 and 3, the orifice 31 is provided at a position offset from the handling screw hole 7. The offset distance L is preferably 20 mm or more from the viewpoint of securing the strength of the base plate 4. Further, as shown in detail in FIG. 4, the orifice 31 is formed with a small diameter (opening area) substantially the same as that of the conventional example, and has a hole length dimension corresponding to the plate thickness t of the lower base plate 4. That is, when the orifice 31 is processed, the orifice 31 is not restricted by the handling screw hole 7 and the length of the orifice 31 can be processed.

  For the above reasons, the inner peripheral surface of the orifice 31 is formed as a diameter-expanded surface 31a that gradually increases in diameter toward both ends, as shown in detail in FIG. In this embodiment, the diameter-expanded surface 31a is a circular arc surface, and the radius of curvature R is set to (1/3) · t.

  In the above configuration, when the air in the air spring main body 2 is compressed (pressurized) / expanded (depressurized) by the vibration of the railway vehicle, the main body side air chamber 2a of the air spring main body 2 and the auxiliary side air chamber of the auxiliary tank 10 are used. Both air flows in and out through the communication path 30 due to the differential pressure between 10a. A damping force is obtained by friction and diffusion generated when the air flow passes through the orifice 31 of the communication passage 30.

  Here, since the air flow passing through the orifice 31 smoothly flows in the vicinity of the entrance / exit of the orifice 31 by the enlarged diameter surface 31a, generation of high-frequency sound (so-called whistling sound) due to turbulent air flow can be suppressed. In other words, conventionally, when the air flow passes through the orifice, it hits the corner of the inlet / outlet of the orifice to cause turbulence, and this turbulence generates high frequency sound (so-called whistling sound). Since it can suppress, generation | occurrence | production of a high frequency sound can be suppressed.

  The generation state of high-frequency sound in the conventional example and this embodiment was compared and examined by experiments. This experimental situation will be specifically described. In an air spring having a dimension specification capable of supporting a railway vehicle and having an effective diameter of 300 to 600φ at a standard height, the support load is 53.9 KN (55 ton, internal pressure 250 KPa), and the air spring standard height is 219 mm. The occurrence state of high frequency sound was examined when the lower excitation amplitude was changed in the range of 1.0 to 10.0 mm and the frequency was changed in the range of 0.2 to 4.0 Hz. When the generation of high frequency sound is not recognized, x is indicated when the generation of high frequency sound is recognized, and the case where the generation of high frequency sound is faint is indicated by Δ, in the conventional example, FIG. In this embodiment, the experimental result of FIG. 5B was obtained. As shown in FIGS. 5A and 5B, in the conventional example, the generation of high-frequency sound was recognized at a frequency of 1.0 Hz or more. However, in this embodiment, the generation of high-frequency sound is completely generated in all frequency bands. Was not recognized.

  As described above, in the present invention, the orifice 31 is provided at a position offset from the handling screw hole 7 of the base plate 4, so that the plate of the base plate 4 is not subject to the restriction of the handling screw hole 7. Since all of the thickness t can be the hole length dimension of the orifice 31, the design freedom of the orifice 31 can be increased, and a high-frequency sound can be suppressed.

  Specifically, since the orifice 31 is formed as a diameter-expanded surface 31a whose inner peripheral surface expands toward both ends, the air flow passing through the orifice 31 is near the entrance / exit of the orifice 31 by the diameter-expanded surface 31a. Therefore, the generation of high-frequency sound due to air turbulence can be suppressed.

  Further, the orifice 31 has an inner circumferential surface formed on the diameter-expanded surface 31a. However, since the center portion of the orifice 31 can maintain the minimum diameter d, generation of high-frequency sound can be prevented while maintaining attenuation characteristics. .

  FIG. 6 shows a cross-sectional view of a first variation of the orifice. As shown in FIG. 6, the orifice 40 of the first modified example has an inner diameter enlarged surface 40 a formed as a curved surface and a curvature radius R set to (½) · t. .

  Also in the first modified example, as in the above-described embodiment, since the inner peripheral surface can be the enlarged surface 40a while ensuring the minimum diameter d of the orifice 40, high-frequency sound is generated while maintaining attenuation characteristics. Can be prevented.

  If the radius of curvature R of the orifice 40 is set in the range of (1/3) · t ≦ R ≦ (1/2) · t, the inner peripheral surface is enlarged to ensure the minimum diameter d of the orifice 40. And is preferable. In other words, if the radius of curvature R is less than (1/3) · t, smooth inflow / outflow of the air flow cannot be achieved, and there is a high possibility of causing turbulence. Further, if the radius of curvature R is larger than (1/2) · t, edges are formed at both ends of the peripheral surface, which increases the possibility of causing intrusion.

  FIG. 7 is a cross-sectional view of a second modification of the orifice. As shown in FIG. 7, the orifice 41 of the second modified example is formed in an elastic body 44 that is disposed in the large-diameter hole 42 of the lower base plate 4 and is held by the support seat 43. And the inner peripheral surface of the orifice 41 is formed as the straight diameter expansion surface 41a.

  Also in the second modified example, as in the above-described embodiment, since the inner peripheral surface is the enlarged diameter surface 41a while ensuring the minimum diameter d of the orifice 41, generation of high-frequency sound can be prevented while maintaining attenuation characteristics. . Moreover, since the orifice 41 is formed in the elastic body 44, since the elastic body 44 absorbs air vibration, there also exists an advantage that generation | occurrence | production of a high frequency sound can be suppressed further.

1 is a cross-sectional view of an air spring according to an embodiment of the present invention. 1 is a plan view of a lower base plate according to an embodiment of the present invention. FIG. 3 shows an embodiment of the present invention and is a cross-sectional view taken along line AA in FIG. 2. FIG. 3 is an enlarged cross-sectional view of the vicinity of the orifice of the base plate according to the embodiment of the present invention. 1A and 1B show an embodiment of the present invention, in which FIG. 4A is a diagram illustrating experimental results of a high-frequency sound generation state in a conventional example, and FIG. 5B is a diagram illustrating experimental results of a high-frequency sound generation state in the present embodiment. It is an expanded sectional view of the 1st modification of an orifice. It is an expanded sectional view of the 2nd modification of an orifice. It is sectional drawing of the air spring of a prior art example. It is the B section enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air spring 2 Air spring main body 2a Main body side air chamber 4 Base plate 7 Handling screw hole 10 Auxiliary tank 10a Auxiliary air chamber 30 Communication hole 31 Orifice 31a Expanded portion 40 Orifice 40a Expanded portion 41 Orifice 41a Expanded portion 44 Elasticity body

Claims (4)

A main body side air chamber is formed inside, an air spring main body in which the main body side air chamber is filled with pressurized air and the elasticity is adjusted by the pressure of the pressurized air, an auxiliary tank having an auxiliary air chamber inside, An air spring comprising a handling screw hole in the base plate of the air spring body, and an orifice communicating the body side air chamber and the auxiliary air chamber,
The air spring according to claim 1, wherein the orifice is provided at a position offset from the handling screw hole of the base plate.   2. The air spring according to claim 1, wherein an inner peripheral surface of the orifice is formed as a diameter-expanded surface that increases in diameter toward both ends.   The air spring according to claim 1, wherein the diameter-expanded surface is an arc surface.   4. The radius of curvature R of the expanded surface is in a range of (1/3) · t ≦ R ≦ (1/2) · t, where t is the thickness of the base plate. The air spring as described in.

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