JP2004183752A - Reciprocating slide type air seal mechanism and sliding material used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reciprocating slide type air seal mechanism in which abrasion progress of an air seal material is reduced, and a sliding material used therefore. <P>SOLUTION: In an air seal mechanism, air seal is executed by reciprocating slide contact between an air seal material and a sliding material, wherein the priority of slide abrasion is given to the air material relative to the sliding material. In the evaluation standard of the sliding surface of the sliding material where the evaluation length is 2.5 mm and the cut off is 0.25 Gaussian, the following relations are satisfied : Wca obtained from the cross section curve: ≤0.30μm, Ra obtained from the roughness curve: ≤0.25μm, and load length ratio tp: ≤20% at 20% of the cut ratio and ≥50% at 30% of of the cut ratio. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２５】
表１中、サンプルＡ〜Ｋは比較例であり、指標値Ｒａ、Ｗｃａ、ｔｐ（カット率２０％、３０％）の少なくともいずれか１つが本発明の規定範囲外であり、サンプルＬ〜Ｒは本発明例であり指標値がいずれも本発明の規定範囲内である。
【００２６】
表１に示したデータを図３および図４にプロットして示す。図３には、表１中の各サンプルについて、Ｒａ値とＷｃａ値の組み合わせに対するエアー漏れの有無を示し、図４には、表１中の各サンプルについて、カット率２０％でのｔｐ値（ｔｐ２０）とカット率３０％でのｔｐ値（ｔｐ３０）の組み合わせに対するエアー漏れの有無を示している。
【００２７】
図３において、エアー漏れ無し（〇）は、Ｒａが本発明の規定範囲である０．２５μｍ以下で且つＷｃａが本発明の規定範囲である０．３０μｍ以下の場合にのみ生じている。ただし、この場合であっても、エアー漏れ有り（×）も生じている。ここでエアー漏れ有り（×）のサンプルは、Ｒａ値およびＷｃａ値は本発明の規定範囲であったが、ｔｐ値が本発明の規定範囲外であった。
【００２８】
すなわち図４に示すように、カット率２０％でのｔｐ値（ｔｐ２０）が２０％以下であって且つカット率３０％でのｔｐ値（ｔｐ３０）が５０％以上である、という本発明の規定範囲内にある組み合わせのサンプルのみがエアー漏れ無し（〇）であった。
【００２９】
すなわち、Ｒａ、Ｗｃａ、ｔｐ２０、ｔｐ３０の全ての指標値が本発明の規定範囲内にある場合にのみエアー漏れを防止することができ、指標値のいずれか１つでも本発明の規定範囲から外れた場合にはエアー漏れを防止できなかった。
【００３０】
このように摺動材の摺動面形態を本発明の規定範囲内に制御することにより、エアー漏れを防止できることが分かる。
【００３１】
更に、エアシール材の摩耗量についても、表１に示したように比較例サンプルＡ〜Ｋが１８０〜２５０μｍであるのに対して、本発明例サンプルＬ〜Ｒは１００〜１２０μｍとほぼ半減していることが分かる。
【００３２】
【発明の効果】
本発明によれば、エアシール材の摩耗進行を低減した往復摺動エアシール機構およびそれに用いるための摺動材が提供される。
【図面の簡単な説明】
【図１】図１は、カット率と負荷長さ率との関係が本発明の規定範囲内である場合について、カット率に対する負荷長さ率ｔｐの変化を表すベアリングカーブの一例を示すグラフである。
【図２】図２は、評価試験に用いた往復摺動エアシール機構の一部を模式的に示す断面図である。
【図３】図３は、Ｒａ値とＷｃａ値との組み合わせに対するエアー漏れの有無を示すグラフである。
【図４】図４は、カット率２０％での負荷長さ率（ｔｐ２０）とカット率３０％での負荷長さ率（ｔｐ３０）との組み合わせに対するエアー漏れの有無を示すグラフである。
【符号の説明】
１０…往復摺動エアシール機構
１１…シリンダチューブ
１１Ａ…周溝
１２…エアシール材
１３…摺動材
１４…エア室[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mechanism for air sealing by reciprocating sliding contact between an air seal material and a sliding material, and a sliding material used for the mechanism.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a reciprocating sliding air seal mechanism is an air-tight sealing mechanism that can reciprocate and slide without lubrication, such as an air spring. A mechanism for air sealing by sliding contact is described. In this case, air sealing is performed by reciprocating sliding contact between a seal ring made of a fluororesin or the like fitted into the circumferential groove of the piston and the metal cylinder tube. That is, the outer peripheral surface of the resin seal ring fitted in the peripheral groove of the reciprocating piston slides on the inner peripheral surface of the fixed metal cylinder tube. On the contrary, as the reciprocating sliding air seal mechanism, the inner peripheral surface of the resin seal ring fitted in the peripheral groove of the fixed cylinder tube comes into sliding contact with the outer peripheral surface of the reciprocating metal piston. There are many forms.
[0003]
In either case, air sealing is performed by reciprocating sliding contact between an air sealing material made of a relatively soft material such as resin and rubber and a sliding material made of a relatively hard material such as metal.
[0004]
As described above, a material such as a resin softer than a metal is used for the air seal material in order to secure airtightness, but an expensive material needs to be used to enhance wear resistance. In addition, a sliding material to be a mating material often has a sliding surface made of metal, and it is customary to reduce the surface roughness and secure the sealing property.
[0005]
However, the use of lubricating oil on the sliding surface of the air seal affects the air pressure, so it is necessary to perform sliding without lubrication or with low lubrication. There has been a problem that this causes a failure of the device.
[0006]
[Patent Document 1]
JP-A-9-303566 (paragraphs 0013 to 0018, FIG. 1)
[0007]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a reciprocating sliding air seal mechanism which solves the above-mentioned conventional problems and reduces the progress of wear of the air seal material, and a sliding material for use in the mechanism.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, air sealing is performed by reciprocating sliding contact between an air seal material and a sliding material, and the air seal material is preferentially slidably worn on the sliding material. In the air seal mechanism,
Under the evaluation conditions that the sliding surface of the sliding material has an evaluation length of 2.5 mm and a cutoff of 0.25 Gaussian, the following relationship is obtained:
Wca obtained from the sectional curve: 0.30 μm or less,
Ra determined from a roughness curve: 0.25 μm or less,
Load length rate tp: 20% or less at a cut rate of 20% and 50% or more at a cut rate of 30%
And a reciprocating sliding air seal mechanism is provided.
[0009]
Furthermore, according to the present invention, an air seal is performed by reciprocating sliding contact between the air seal material and the sliding material, and the sliding material used in the air seal mechanism in which the air seal material slides and wears preferentially with respect to the sliding material. And
Under the evaluation condition that the sliding surface has an evaluation length of 2.5 mm and a cutoff of 0.25 Gaussian, the following relationship is obtained:
Wca obtained from the sectional curve: 0.30 μm or less,
Ra determined from a roughness curve: 0.25 μm or less,
Load length rate tp: 20% or less at a cut rate of 20% and 50% or more at a cut rate of 30%
Slidable material for a reciprocating sliding air seal mechanism, characterized in that:
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention defines Wca, Ra, and tp as indices of the surface morphology as described above. Here, Wca represents a component having a long wavelength such as an undulation component included in the cross-sectional curve, while Ra is an arithmetic average roughness, and the above-mentioned long-wavelength component is removed (cut off) from the cross-sectional curve. It is determined from the roughness curve.
[0011]
That is, in the present invention, among the surface morphologies, irregularities having a long wavelength such as undulation are limited using Wca as an index, and at the same time, irregularities having a short wavelength that is representative of surface roughness are generally limited using Ra as an index.
[0012]
The present invention additionally limits the load length ratio tp. The load length ratio tp depends on the cross-sectional profile of the unevenness forming the sliding surface. When the load length ratio tp satisfies the specified range of the present invention, a bearing curve (a curve representing a change in the load length ratio depending on the cut ratio) is as shown in FIG. 1, for example. The horizontal axis is the cut rate, the vertical axis is the load length rate tp, and the bearing curve corresponds to the cross-sectional profile of the unevenness of the sliding surface (specifically, the total average of the cross-sectional profiles of the individual unevennesses forming the sliding surface). I have. The present invention uses the relationship between the cut rate and the load length rate as an index of the surface morphology. The point at which the load length rate tp becomes 20% or less at a cut rate of 20% (point A in the illustrated example) is determined. The bearing curve is defined so as to pass through a point (point B in the illustrated example) at which the load length ratio tp becomes 50 or more at a rate of 30%, thereby defining the cross-sectional profile of the unevenness forming the sliding surface.
[0013]
By setting the sliding surface configuration of the sliding material that is to be slid with the air seal material within the above specified range, the wear progress of the air seal material can be significantly reduced.
[0014]
A resin such as a fluorine resin, a synthetic rubber such as a silicone rubber, or the like is generally used for the air seal material, and a metal such as an aluminum alloy is generally used for a sliding material as a sliding partner.
[0015]
There is no particular limitation on the method for setting the sliding surface form of the sliding material within the range specified in the present invention. For example, the following method can be used.
[0016]
[Method 1]
An outer peripheral surface serving as a sliding surface of the cylindrical sliding member is processed in advance into a mirror surface, and a laser beam is irradiated to the mirror surface to form a minute depression. At this time, the size and pitch of the dents to be formed are controlled in the circumferential direction of the sliding material to a desired value by controlling the rotation speed around the cylindrical axis and pulse control of the laser beam, and at the same time, in the longitudinal direction of the sliding material. Processing to control to a desired value is possible by the slit corresponding to the moving speed in the cylindrical axis direction and the pitch. Generally, it is desirable that the spot diameter of the laser beam be 50 μm or less.
[0017]
[Method 2]
After finishing the sliding surface of the sliding material by machining, a desired surface form is obtained by multi-stage shot blasting. That is, shot particles having a large particle size are used for the initial shot in order to enhance smoothness, and particles having a small particle size are used for the final shot in order to generate minute depressions. The shot particles for the final shot preferably have a particle size of 50 μm or less.
[0018]
The above method is only an example, and any surface processing method capable of forming a required surface morphology may be used. In general, including the above examples, the surface morphology can be adjusted by local processing such as mechanical grinding, shot blasting, various types of polishing, chemical etching, electrolytic etching, electron beam processing, or a combination thereof. .
[0019]
【Example】
As the reciprocating sliding air seal mechanism according to the present invention, the air spring shown in FIG. 2 is used to change the sliding surface form of the sliding material, which is the sliding partner of the air sealing material, in various ways to reduce the amount of seal material wear and air leakage. It was measured.
[0020]
The reciprocating sliding air seal mechanism 10 shown in FIG. 2 has a ring-shaped air seal material 12 fitted in a circumferential groove 11A provided along the inner circumference of a cylinder tube 11, and a sliding material 13 as a piston is Reciprocatingly slides in the axial direction (arrows in the figure). The outer peripheral surface of the sliding member 13 is a sliding surface with the inner peripheral surface of the air seal member 12. In the figure, air at a predetermined pressure is maintained in an air chamber 14 below the sliding member 13, and exerts a spring action against a load applied to the upper surface of the sliding member 13.
[0021]
As the air seal material 12, a commercially available product manufactured by Teflon (trade name) was used. The sliding material 13 is made of an aluminum alloy, and is machined into a predetermined shape by mechanically cutting an aluminum alloy round bar, and then adjusted to various surface forms by shot blasting, mechanical grinding, and polishing.
[0022]
The inner diameter of the air seal member 12 and the outer diameter of the sliding member 13 were both about 30 mm. The air pressure in the air chamber 14 was about 1 MPa, and air was supplied from an external pressurized cylinder via a regulator. The reciprocating sliding stroke was 30 mm, the sliding speed was gradually increased from 1000 strokes / minute to a maximum of 9000 strokes / minute, and was maintained for 60 minutes.
[0023]
The test results are summarized in Table 1. Rz values (ten-point average roughness) in Table 1 are not specified in the present invention, but are also shown for reference.
[0024]
[Table 1]

[0025]
In Table 1, Samples A to K are comparative examples, and at least one of index values Ra, Wca, and tp (cut ratio 20%, 30%) is out of the specified range of the present invention. This is an example of the present invention, and each index value is within the range specified by the present invention.
[0026]
The data shown in Table 1 are plotted and shown in FIGS. FIG. 3 shows the presence or absence of air leakage with respect to the combination of the Ra value and the Wca value for each sample in Table 1, and FIG. 4 shows the tp value (at a cut rate of 20%) for each sample in Table 1 tp20) and the tp value (tp30) at a cut rate of 30% indicate the presence or absence of air leakage.
[0027]
In FIG. 3, no air leakage (〇) occurs only when Ra is 0.25 μm or less, which is the specified range of the present invention, and Wca is 0.30 μm or less, which is the specified range of the present invention. However, even in this case, there is air leakage (x). Here, in the sample with air leakage (x), the Ra value and the Wca value were within the specified range of the present invention, but the tp value was out of the specified range of the present invention.
[0028]
That is, as shown in FIG. 4, the present invention defines that the tp value (tp20) at a cut rate of 20% is 20% or less and the tp value (tp30) at a cut rate of 30% is 50% or more. Only the samples of the combinations within the range showed no air leakage (〇).
[0029]
That is, air leakage can be prevented only when all index values of Ra, Wca, tp20, and tp30 are within the specified range of the present invention, and any one of the index values falls outside the specified range of the present invention. Air leak could not be prevented.
[0030]
It can be seen that air leakage can be prevented by controlling the sliding surface configuration of the sliding member within the range specified in the present invention.
[0031]
Furthermore, as for the abrasion loss of the air seal material, as shown in Table 1, Comparative Samples A to K were 180 to 250 μm, whereas Samples L to R of the present invention were almost halved to 100 to 120 μm. I understand that there is.
[0032]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the reciprocating sliding air seal mechanism which reduced the abrasion progress of an air seal material and the sliding material used for it are provided.
[Brief description of the drawings]
FIG. 1 is a graph showing an example of a bearing curve representing a change of a load length ratio tp with respect to a cut ratio when a relationship between a cut ratio and a load length ratio is within a range specified by the present invention. is there.
FIG. 2 is a cross-sectional view schematically showing a part of a reciprocating sliding air seal mechanism used in an evaluation test.
FIG. 3 is a graph showing the presence or absence of air leakage with respect to a combination of a Ra value and a Wca value.
FIG. 4 is a graph showing the presence / absence of air leakage with respect to a combination of a load length ratio (tp20) at a cut rate of 20% and a load length ratio (tp30) at a cut rate of 30%.
[Explanation of symbols]
10 reciprocating sliding air seal mechanism 11 cylinder cylinder 11A peripheral groove 12 air seal 13 sliding member 14 air chamber

Claims (2)

The air seal mechanism performs air sealing by reciprocating sliding contact between the air seal material and the sliding material, and the air seal material preferentially slides and wears on the sliding material.
Under the evaluation conditions that the sliding surface of the sliding material has an evaluation length of 2.5 mm and a cutoff of 0.25 Gaussian, the following relationship is obtained:
Wca obtained from the sectional curve: 0.30 μm or less,
Ra determined from a roughness curve: 0.25 μm or less,
Load length rate tp: 20% or less at a cut rate of 20% and 50% or more at a cut rate of 30%
A reciprocating sliding air seal mechanism characterized by satisfying the following. A sliding member used for an air seal mechanism in which an air seal is performed by reciprocating sliding contact between the air sealing member and the sliding member, and the air sealing member preferentially slides and wears on the sliding member,
Under the evaluation condition that the sliding surface has an evaluation length of 2.5 mm and a cutoff of 0.25 Gaussian, the following relationship is obtained:
Wca obtained from the sectional curve: 0.30 μm or less,
Ra determined from a roughness curve: 0.25 μm or less,
Load length rate tp: 20% or less at a cut rate of 20% and 50% or more at a cut rate of 30%
A sliding material for a reciprocating sliding air seal mechanism, characterized by satisfying the following.

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