JPS6041258B2 - FRP spring plate - Google Patents

Description

【発明の詳細な説明】 本発明は車輪用ＦＲＰ板‘よね装置などに使用されるＦ
ＲＰ製の板ばねに関する。[Detailed Description of the Invention] The present invention is an FRP plate used in a wheel FRP plate twisting device, etc.
Regarding leaf springs made of RP.

ＦＲＰ（繊維強化樹脂）毅のばね板は、従来の鋼製ばね
板に比して大幅な軽量化が図れることから、特に自動車
用板ばねとして有望である。Spring plates made of FRP (fiber reinforced resin) Tsuyoshi are particularly promising as leaf springs for automobiles because they are significantly lighter in weight than conventional steel spring plates.

第１図および第２図に示されるように従来のばね板ａは
一般に断面が偏平な矩形状をなしており、従ってばね板
ａが操む際のひずみが零（従って応力も零）となる中立
軸は、ばね板の厚み方向の中心位置○と一致する。とこ
ろでＦＲＰ‘まね板の疲労試験を行なった結果、ＦＲＰ
‘まね板では圧縮応力の生じる面（Ｃｏｍｐｒｅｓｓｉ
ｏｎＳｉｄｅ＝Ｃ・Ｓ）の方が引張り応力が生じる側の
面（Ｔｅ雌ｉｏｎＳｉｄｅ＝Ｔ・Ｓ）よりも亀裂を生じ
易いことが明らかとなった。As shown in Figures 1 and 2, the conventional spring plate a generally has a rectangular shape with a flat cross section, so that when the spring plate a is manipulated, the strain is zero (therefore, the stress is also zero). The neutral axis coincides with the center position ○ in the thickness direction of the spring plate. By the way, as a result of conducting a fatigue test on FRP' rolling board, it was found that FRP
'In a rolling board, the surface where compressive stress occurs (Compressi
It has become clear that cracks are more likely to occur on the side surface (onSide=C・S) than on the side where tensile stress occurs (Te female ionSide=T・S).

その理由は、一般に樹脂を含浸させた強化繊維は引張り
には強いが圧縮に対しては座屈を生じることにより強度
が不足するためと考えられる。一方、従来の鋼製ばね板
にあっては、圧縮応力側の面（Ｃ・Ｓ）に比べて引張り
応力側の面（Ｔ・Ｓ）に亀裂を生じ易く、かつ亀裂の成
長も速いことが従来から知られており、このため従来の
鋼製ばね板では引張り応力側に例えばショットピーニン
グを施すなどして耐久性を高めることが行なわれている
。The reason for this is thought to be that reinforcing fibers impregnated with resin are generally strong in tension, but buckle in compression, resulting in insufficient strength. On the other hand, in conventional steel spring plates, cracks are more likely to form on the tensile stress side (T/S) than on the compressive stress side (C/S), and the cracks grow faster. This has been known for a long time, and for this reason, in conventional steel spring plates, the tensile stress side is subjected to, for example, shot peening to increase the durability.

例えば第３図はＪＩＳＧ４８０１で採用している断面非
矩形状の鋼製ばね板であって、この場合、ぱね板ｂの厚
み方向中心位置○を境として圧縮応力（Ｃ・Ｓ）側の断
面積を引張応力（Ｔ・Ｓ）側の断面積よりも４・さくす
ることにより（例えば圧縮応力側に浅い溝ｃを長手方向
に設ける）、中立鞠ｎを上記中心位瞳○よりも引張り応
力（Ｔ・Ｓ）側に偏寄こせ、こうすることによって引張
り応力（Ｔ・Ｓ）側に作用する応力を圧縮応力（Ｃ・Ｓ
）側のそれよりも４・さくしている。For example, Fig. 3 shows a steel spring plate with a non-rectangular cross section adopted in JIS G4801. By making the cross-sectional area of the neutral ball n smaller than the cross-sectional area of the tensile stress (T・S) side (for example, by providing a shallow groove c in the longitudinal direction on the compressive stress side), the tensile stress ( By doing this, the stress acting on the tensile stress (T/S) side becomes compressive stress (C/S).
) side is 4. smaller than that on the side.

従ってこの場合、引張り応力（Ｔ・Ｓ）側の応力が緩和
され、この部位の亀裂の発生が抑制されることになるか
ら、単なる矩形断面のものに比して同等の強度であれば
断面積が少なくて済み、その分だけ童量が軽くて済む。
あるいは重量が同じであれば、より耐久性の高いばね板
が得られることになる。しかしながらこれをそのままＦ
ＲＰばね板に適用すると、ばね板の圧縮応力側に過大な
応力が生じることになるため、鋼製ぱね板の場合には問
題ないが、前記したようにＦＲＰばね板の場合にはかえ
って圧縮応力の増大が耐久性の低下を招くことになり、
ばね板の耐久性を向上できないことがわかった。本発明
はこのような背景のもとになされたものであり、その目
的とするところは、圧縮応力側の面に生じる亀裂の発生
を防止することができ、耐久性の向上を図ることのでき
るＦＲＰばね板を提供することにある。Therefore, in this case, the stress on the tensile stress (T・S) side is relaxed and the generation of cracks in this area is suppressed, so if the strength is equivalent to that of a simple rectangular cross-section, the cross-sectional area This means that the amount of children can be reduced accordingly.
Alternatively, if the weight is the same, a more durable spring plate can be obtained. However, this is F as it is.
If applied to RP spring plates, excessive stress will be generated on the compressive stress side of the spring plate, so this will not be a problem in the case of steel spring plates, but as mentioned above, in the case of FRP spring plates, the compressive stress will increase. An increase in this will lead to a decrease in durability,
It was found that the durability of the spring plate could not be improved. The present invention was made against this background, and its purpose is to prevent the occurrence of cracks on the surface facing compressive stress and improve durability. Our objective is to provide FRP spring plates.

すなわち本発明のＦＲＰ製‘まね板においては、引張り
応力側の面の幅方向両端部は板厚の約半分程度の半径を
もつ約４分の１円形断面の曲面部を介してばね板の側面
に連なるとともにこの両端曲面部間の部位は平坦とし、
一方、圧縮応力側の面の幅方向両端部は、ほぼ直角の角
部を介してばね板の側面に連なるとともにこの両端角部
間の部位を平坦とすることにより、ばね板の厚み方向中
心位置を境として引張り応力側の断面積を圧縮応力側の
断面積よりも少なくしたものである。In other words, in the FRP manipulating board of the present invention, both ends in the width direction of the surface on the tensile stress side are connected to the side surface of the spring board through the curved surface portion having a circular cross section of about 1/4 and having a radius of about half the board thickness. The area between the curved surfaces at both ends is flat,
On the other hand, both ends in the width direction of the surface on the compressive stress side are connected to the side surfaces of the spring plate through almost right-angled corners, and by making the area between the two end corners flat, the center position in the thickness direction of the spring plate is The cross-sectional area on the tensile stress side is smaller than the cross-sectional area on the compressive stress side.

こうして中立軸を圧縮応力側に偏寄こせ、これによって
ばね板が榛んだ時に圧縮応力側に生じる応力を軽減させ
るようにしている。以下本発明の−実施例について第４
図ないし第６図を参照して説明する。In this way, the neutral axis is biased toward the compressive stress side, thereby reducing the stress generated on the compressive stress side when the spring plate is deflected. The following is a fourth example of the present invention.
This will be explained with reference to FIGS. 6 through 6.

第４図は車鋼懸架用のＦＲＰ重ね板ばね装置を示すもの
であって、図中１・・・は複数枚のＦＲＰ製のばね板で
ある。これらＦＲＰ製‘まね板１・・・は、その中央部
分においてセンタボルト２によって互いに締結されてい
るとともに、第１番目のばね板ｌａの両端部には金属製
の目玉部材３，３が取着されている。そしてこれら目玉
部材３，３は車体側に取付けられ、また上記センタボル
ト２付近には車軸側のアクスルシャフト（図示せず）が
取付けられるようになっている。従って、この重ね板ば
ね装置は、使用状態において両端の目玉部材３，３に下
向きの荷重が付与され、ばね１・・・の両端側が下向き
に榛むようになっている。FIG. 4 shows an FRP stacked plate spring device for car steel suspension, and in the figure, 1 . . . indicates a plurality of FRP spring plates. These FRP playing plates 1... are fastened to each other by a center bolt 2 at their central portions, and metal eyeball members 3, 3 are attached to both ends of the first spring plate la. has been done. These eyepiece members 3, 3 are attached to the vehicle body side, and an axle shaft (not shown) on the axle side is attached near the center bolt 2. Therefore, when this stacked leaf spring device is in use, a downward load is applied to the center members 3, 3 at both ends, so that both end sides of the springs 1 sag downward.

つまり各ばね板１・・・は、図示上側が引張り応力側の
面（Ｔ・Ｓ）となり、また下側が圧縮応力側の面（Ｃ・
Ｓ）となる。そして第６図に示されるように、引張り応
力側の面の幅方向両端部は、板厚の半分程度の半径ｒを
もつ約４分の１円兄断面の曲面部５，５を介して、ばね
板の側面に連なっている。In other words, for each spring plate 1..., the upper side in the drawing is the surface on the tensile stress side (T・S), and the lower side is the surface on the compressive stress side (C・
S). As shown in FIG. 6, both ends in the width direction of the surface on the tensile stress side are connected to each other via curved surfaces 5, 5 each having a cross section of about a quarter circle with a radius r about half the plate thickness. It is connected to the side of the spring plate.

これら両端曲面部５，５間の部位は平坦である。一方、
圧縮応力側の面の幅方向両端部は、ほぼ直角の角部６，
６を介してばね板の側面に連なる。これら両端角部６，
６間の部位は平坦である。こうして、厚み方向中心位置
○を境に、引張り応力（Ｔ・Ｓ）側の断面積が引張り応
力（Ｔ・Ｓ）側の断面鏡よりも小さくなっている。なお
、角部６，６にバリ取りなどの目的で多少の面取りを行
なう場合もある。以上のような断面形状にすることによ
って、上記厚み方向中心位置○を基準とした場合に引張
り応力（Ｔ・Ｓ）側の断面一次モーメント（面積モーメ
ント）は、圧縮圧力（ＣＯＳ）側の断面一次モーメント
よりも小さくなり、従ってばね板１を操ませた場合には
、その中立軸ｎは厚み方向中心位置０に対して圧縮応力
（Ｃ・Ｓ）側に偏寄することになる。The region between these curved end portions 5, 5 is flat. on the other hand,
Both ends in the width direction of the surface on the compressive stress side are substantially right-angled corners 6,
6 to the side surface of the spring plate. These both end corner portions 6,
The area between 6 and 6 is flat. In this way, the cross-sectional area on the tensile stress (T·S) side is smaller than that of the cross-sectional mirror on the tensile stress (T·S) side, with the thickness direction center position ◯ as a boundary. Note that the corners 6, 6 may be slightly chamfered for the purpose of deburring or the like. By creating the cross-sectional shape as described above, the first moment of area (area moment) on the tensile stress (T S) side becomes the same as the first moment of area on the compressive pressure (COS) side when the center position ○ in the thickness direction is used as a reference. Therefore, when the spring plate 1 is manipulated, its neutral axis n will be biased toward the compressive stress (C·S) side with respect to the center position 0 in the thickness direction.

従って第６図に示されるように、圧縮応力側の最大応力
。Therefore, as shown in FIG. 6, the maximum stress on the compressive stress side.

ｃは引張り応力側の最大最力。ｔに比べて小さくなる。
換言すると、単なる矩形断面形状の従来品（第２図参照
）の場合に比べて引張り応力（Ｔ・Ｓ）側の応力のを高
く、また圧縮応力（Ｃ・Ｓ）側の応力。ｃを低下させる
ことができる。一例として板厚ｔ＝２仇廠、板幅ｂ＝５
比岬、曲面状部分５の半径ｒ：ＩＱ舷とした場合、中立
軸ｎを基準として周知の断面一次モーメントの計算式に
よって。c is the maximum force on the tensile stress side. It becomes smaller compared to t.
In other words, the stress on the tensile stress (T/S) side is higher and the stress on the compressive stress (C/S) side is higher than in the case of a conventional product with a simple rectangular cross-sectional shape (see Figure 2). c can be lowered. As an example, plate thickness t = 2 units, plate width b = 5
When the radius r of the curved surface portion 5 is IQ, the calculation formula for the first moment of area is calculated based on the neutral axis n.

上と。ｃの比を算出すると、圧縮応力側の最大応力ｏｃ
は引張り応力側の最大応力ｏｔに比べて約８％の応力低
下が達成できることが判る。しかして、例えばガラス繊
維を強化繊維として用いたフィラメントワインディング
法によるＧＦＲＰのテストピースの場合、本発明者が行
なった試験結果によると、圧縮強さが約９０ｋ９／柵に
対し引張り強さは約１４０ｋ９／めであり、圧縮に対し
て引張り方向に１５０％以上の強度を有しているから、
上述したようにＦＲＰばね板１において引張り応力側の
応力を圧縮応力側の応力よりも１０％程度増大させても
強度的には何ら問題を生じない。そしてこのような応力
配分とすることによって圧縮応力側の亀裂発生を防止で
き、ばね板１のプル園な耐久性向上が可能となるもので
あるなお、ばね板を複数備えた重ね板ばねの場合には、
例えば親ばねにのみ本発明によるばね板を使用し、他の
ばね板は一般的な断面矩形状のものを使用するように組
合わせてもよい。Above and above. By calculating the ratio of c, the maximum stress on the compressive stress side oc
It can be seen that a stress reduction of about 8% can be achieved compared to the maximum stress ot on the tensile stress side. For example, in the case of a GFRP test piece made by the filament winding method using glass fiber as a reinforcing fiber, the compressive strength is about 90k9/fence, and the tensile strength is about 140k9, according to the test results conducted by the present inventor. /, and has a strength of 150% or more in the tensile direction compared to compression,
As mentioned above, even if the stress on the tensile stress side of the FRP spring plate 1 is increased by about 10% compared to the stress on the compressive stress side, no problem will arise in terms of strength. By distributing stress in this way, cracks can be prevented from occurring on the compressive stress side, and the durability of the spring plate 1 can be greatly improved.In addition, in the case of a stacked leaf spring with multiple spring plates for,
For example, the spring plate according to the present invention may be used only for the main spring, and the other spring plates may have a general rectangular cross section.

本発明は以上説明したように、ＦＲＰ製ばね板の引張り
応力側の幅方向両端部は曲面部を介してばね板の側面に
連続させ、また圧縮応力側の幅方向両端部はほぼ直角を
介してばね板の側面に連続させることによって、中立軸
を圧縮応力側に偏寄させたものである。As explained above, in the present invention, both widthwise ends of the FRP spring plate on the tensile stress side are connected to the side surfaces of the spring plate via a curved surface, and both widthwise ends on the compressive stress side are connected through a substantially right angle. By connecting the lever to the side surface of the spring plate, the neutral axis is biased toward the compressive stress side.

従って圧縮応力側の応力を軽減させることができ、ＦＲ
Ｐばね板の耐久性を大幅に向上できる。しかも上記曲面
部を除く部位は全て平坦であるから、引張り応力側の表
面応力をほぼ一様にすることができ、耐久性を維持でき
る。Therefore, the stress on the compressive stress side can be reduced, and the FR
The durability of the P spring plate can be greatly improved. Moreover, since all the parts except the curved surface part are flat, the surface stress on the tensile stress side can be made almost uniform, and durability can be maintained.

また、引張り応力側は板厚の約半分程度の半径をもつ約
４分の１円形断面の曲面部を介してばね板の側面に連な
るようにしているので、引張り応力側の面に応力進中を
生じることを避けることができ、しかもこの曲面部を除
く部位は平坦であり、平坦な部分の面積を広くとれるか
ら、例えば重ね板ばねに用いた場合などにおいてＵボル
トなどでクランプしても割れにくいものとなる。しかも
圧縮応力側の面とばね板の側面とが直角に交わるから、
成形型からの雛型が容易であり、型形状も簡易で済む。In addition, the tensile stress side is connected to the side surface of the spring plate through a curved surface with a radius of about half the plate thickness and a cross section of about a quarter of a circle, so that the stress is progressing to the surface on the tensile stress side. Moreover, since the parts other than this curved surface are flat, and the area of the flat part can be made large, for example, when used in stacked leaf springs, even if clamped with U bolts, etc., it will not crack. It becomes difficult. Moreover, since the surface on the compressive stress side and the side surface of the spring plate intersect at right angles,
It is easy to create a template from a mold, and the shape of the mold can be simple.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来のＦＲＰばね板を示す斜視図、第２図は第
１図中のローロ線に沿うとまね板の断面図、第３図は従
来の鋼製ばね板の断面形状の一例を示す概略図、第４図
ないし第６図は本発明の一実施例を示し、第４図は車鞠
用ＦＲＰ板ばね装置の正面図、第５図はＦＲＰばね板の
斜視図、第６図はばね板の断面形状を応力分布とともに
示す概略図である。 １・…・・ＦＲＰばね板、０…・・・ばね板の厚み方向
中心位置、ｎ・・・・・・中立軸、Ｔ・Ｓ・・・・・・
引張り応力側の面、Ｃ・Ｓ・・・・・・圧縮応力側の面
。 第１図第２図 第３図 第４図 第５図 第６図Figure 1 is a perspective view of a conventional FRP spring plate, Figure 2 is a sectional view of the rolling plate taken along the Rolo line in Figure 1, and Figure 3 is an example of the cross-sectional shape of a conventional steel spring plate. 4 to 6 show an embodiment of the present invention, FIG. 4 is a front view of an FRP leaf spring device for a car ball, FIG. 5 is a perspective view of an FRP spring plate, and FIG. FIG. 2 is a schematic diagram showing the cross-sectional shape of a spring plate along with stress distribution. 1...FRP spring plate, 0...Center position in the thickness direction of the spring plate, n...Neutral axis, T/S...
Surface on the tensile stress side, C・S... Surface on the compressive stress side. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

【特許請求の範囲】[Claims] １ 厚み方向の一方の面が引張り応力側となりまた他方
の面が圧縮応力側となるような曲げ荷重が付与されるＦ
ＲＰ製ばね板において、引張り応力側の面の幅方向両端
部は、板厚の約半分程度の半径をもつ約４分の１円形断
面の曲面部を介してばね板の側面に連なるとともにこの
両端曲面部間の部位は平坦とし、一方、圧縮応力側の面
の幅方向両端部は、ほぼ直角の角部を介してばね板の側
面に連なるとともにこの両端角部間の部位を平坦とする
ことにより、ばね板の厚み方向中心位置を境として引張
り応力側の断面積を圧縮応力側の断面積よりも少なくし
たことを特徴とするＦＲＰ製ばね板。1 A bending load is applied such that one surface in the thickness direction is on the tensile stress side and the other surface is on the compressive stress side.
In a spring plate made of RP, both ends in the width direction of the surface on the tensile stress side are connected to the side surface of the spring plate via a curved surface portion having a radius of about half the plate thickness and a cross section of about a quarter circle, and these both ends The area between the curved surfaces should be flat, while both ends in the width direction of the surface on the compressive stress side should be connected to the side surfaces of the spring plate via approximately right-angled corners, and the area between these two end corners should be flat. An FRP spring plate characterized in that the cross-sectional area on the tensile stress side is smaller than the cross-sectional area on the compressive stress side with respect to the central position in the thickness direction of the spring plate.