JP3923207B2 - Transmission belt and belt drive device - Google Patents

Description

【００３４】
上記経時＋走行寸法変化率の結果について考察すると、上記の表１から判るように、発明例１及び比較例１，２では共に０．６％台に止どまっているのに対し、比較例３〜６では小さいもの（比較例３，４）でも０．７％台であり、比較例６では１．１１％に達している。これは、例えば比較例３，５から判るように、走行後ベルト伸びが発明例１及び比較例１，２の場合よりも小さくても、それ以上にベルト経時寸法変化の値が大きいためである。
【００３５】
さらに、発明例１及び比較例２を対比すると、発明例１の場合には初期モジュラスが１５０ｇ／ｄｅを少し超えた程度であっても良好な寸法安定性を得られることが判る。この点について、本発明者等は、ＰＶＡの場合（比較例１，２）には初期モジュラスの下限値をＰＥＮの場合（発明例１）よりも高くする（例えば略３００ｇ／ｄｅ程度にする）必要があると考えている。
【００３６】
一方、比較例３〜６について考察すると、例えば比較例３，５の場合のように、ディップ処理時のテンションを高くすることで走行後ベルト伸びを小さくできても、逆にベルト経時寸法変化は悪化する等のことから、ディップ処理の条件を変更するだけでは、生コードのときの特性（乾熱収縮率、乾熱時収縮応力及び初期モジュラス）を離れて寸法安定性を総合的に大きく改善するのは困難であることが判る。
【００３７】
換言すると、上記乾熱収縮率、乾熱時収縮応力及び初期モジュラスの各特性値を押さえておけば、ディップ処理等の条件の多少の違いに拘らず、ベルト経時寸法変化と、走行後ベルト伸びとを共に小さく抑えることができ、総合的に優れた寸法安定性をベルトに付与できるようになることが判る。
【００３８】
【発明の効果】
以上説明したように、請求項１〜４の発明によれば、ベルト仕上り時の寸法のばらつきや、保管時におけるベルト経時寸法変化を小さくすることができ、かつ走行によるベルト伸びも小さくすることができる故に、優れた寸法安定性の伝動ベルトを提供することができる。
【００３９】
特に、請求項２〜４の発明によれば、上記伝動ベルトをＶリブドベルトとしたので、このＶリブドベルトが使用されるサーペンタインドライブにおいて、走行中のベルト張力を一定に保つためのテンショナの作動スペースを小さくすることができ、その分だけエンジンルームに占めるサーペンタインドライブのスペースを小さくすることができる。よって、サーペンタインドライブを採用することによるエンジンルームのコンパクト化及び軽量化に寄与することができる。
【図面の簡単な説明】
【図１】 この発明の実施形態に係るＶリブドベルトの基本構成をベルト長さ方向と直交する平面で切断して示す斜視図である。
【図２】 サーペンタインドライブのレイアウトを示す概略図である。
【図３】 オートテンショナでのアーム長さによる捩りトルクの大きさを説明するための概略図である。
【図４】 一定雰囲気温度による保管の下でのベルト外周長の変化を経時的に示す特性図である。
【符号の説明】
１ 接着ゴム層（ベルト本体）
２ 心線
３ リブゴム層（ベルト本体）
４ リブ
Ｂ Ｖリブドベルト（伝動ベルト）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmission belt in which a belt core wire is embedded and a belt transmission device using the transmission belt, and more particularly, to a measure for reducing both dimensional change of the belt itself with time and elongation during belt running.
[0002]
[Prior art]
For example, in a transmission belt used for driving auxiliary machines such as an air conditioner and an alternator of an automobile with the rotational driving force of an engine, a V-ribbed belt has been widely used instead of the V-belt. The V-ribbed belt includes, as a basic configuration, an adhesive rubber layer and a rib rubber layer integrally laminated on the bottom surface side of the adhesive rubber layer. A plurality of ribs provided to extend in the belt width direction are formed at predetermined pitch intervals in the belt width direction. In the adhesive rubber layer, the core wire extends in the belt length direction and is embedded in a spiral shape with a predetermined pitch interval in the belt width direction. As the core wire, for example, as described in Japanese Patent Publication No. 55-50578, a polyester fiber having an automatic tension function (hereinafter referred to as PET) is generally used.
[0003]
By the way, in recent years, multi-axis drive transmission called serpentine drive has attracted attention for the purpose of reducing the number of belts and reducing the mounting space of an auxiliary machine in a driving apparatus for an auxiliary machine for an automobile. In this serpentine drive, a large number of auxiliary machines are driven through a single belt. As illustrated in FIG. 2, the pulleys 11 to 16 connected to the auxiliary machines are the same. One belt B, which is arranged on a plane and wound in a serpentine shape (meandering shape) between the pulleys 11 to 16, is driven, while the tension of the belt B is adjusted to an auto tensioner (17 in the figure). This is a system which is always controlled by a belt pressing pulley of an auto tensioner. This system was developed in the first half of the 1970s with the advent of V-ribbed belts, including research on auto tensioners. In addition to improved belt maintainability and reliability, As its reliability has increased, its use as an auxiliary drive system is being studied.
[0004]
As a belt suitable for such a serpentine drive,
(1) Small dimensional change over time of the belt itself,
(2) The belt stretches little while running,
That is, it is important for the belt to have a small dimensional change under any circumstances. In other words, the smaller the belt dimensional change, the easier it is to design the belt tension allowance by the tensioner, and the smaller the working space of the tensioner, the smaller the space for the serpentine drive in the engine room. By adopting such a serpentine drive, the engine room itself can be saved in space, and the overall weight can be reduced.
[0005]
[Problems to be solved by the invention]
However, in the conventional V-ribbed belt, it is difficult to say that the dimensional change is sufficiently small, and therefore, it is insufficient to make the engine room compact by adopting the serpentine drive.
[0006]
That is, if the belt dimensional change is large, the working space of the tensioner is correspondingly increased, and the space for the serpentine drive occupying the engine room is correspondingly increased. As a result, downsizing of the engine room is hindered. It is.
[0007]
The present invention has been made in view of the above points, and its main purpose is to clarify the characteristics of a core wire that influences the dimensional change of the belt in a core wire used for a transmission belt such as a V-ribbed belt, and By appropriately setting the characteristic value, it is possible to suppress both the dimensional change of the belt itself over time and the belt elongation after running, and to provide a belt with excellent dimensional stability. .
[0008]
And, for the V-ribbed belt used for the serpentine drive, the working space of the tensioner can be reduced, and the space for the serpentine drive in the engine room can be reduced accordingly. The goal is to make a significant contribution to making the room more compact.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, PEN (polyethylene-2,6-naphthalate) fiber is used as the material of the core wire, and when twisted, that is, in the state of raw cord The initial tensile resistance (initial modulus) is set appropriately. In addition, based on the knowledge that the characteristic values of the dry heat shrinkage rate and the shrinkage stress during dry heat greatly affect the dimensional stability of the transmission belt, by appropriately setting each characteristic value, the dimensional change over time In addition, the elongation during belt running can be further reduced.
[0010]
Specifically, in the invention of claim 1, in the transmission belt having the rubber layer in which the core wire is embedded, the core wire is made of twisted PEN, that is, polyethylene-2,6-naphthalate fiber, the initial tensile resistance degree when the raw cord state is 158.0g / de, and an initial tensile resistance degree after dipping the core wire a 190.2g / de, after dipping of the core wire The initial tensile resistance is larger than the initial tensile resistance when the cord is in the raw cord state. It is more preferable that the dry heat shrinkage at 150 ° C. is 1.0% or less and the dry heat shrinkage stress is 0.2 g / de or less when the twisted state is applied.
[0011]
After the strand is twisted, the core wire is actually subjected to, for example, an isocyanate-based or epoxy-based pretreatment, and then an adhesive such as an RFL liquid is applied. Thereafter, the core wire is stretched at a high temperature and heated. By being subjected to the fixing process, a tensile body for the belt is obtained. The above values are taken when the raw code state before the series of processes is performed and after the dip process. Each of the above characteristic values is measured based on JIS L-1017 (1983). Specifically, the dry heat shrinkage rate is determined by leaving it at an atmospheric temperature of 150 ° C. for 30 minutes, for example. Further, the shrinkage stress at the time of dry heat is obtained by leaving it to stand for 3 minutes at an ambient temperature of 150 ° C., for example.
[0012]
In the above configuration, when the dry heat shrinkage rate and the dry heat shrinkage stress at 150 ° C. of the core wire are suppressed to 1.0% or less and 0.2 g / de or less, respectively, the dimensional change of the belt itself over time Becomes smaller. As can be clearly seen from Comparative Examples 1 to 4 using PET to be described later, when the dry heat shrinkage rate and the dry heat shrinkage stress exceed 1.0% and 0.2 g / de, respectively, the dimensional change with time. As a result, the transmission belt having good dimensional stability cannot be obtained, and the quality of the belt may be significantly deteriorated.
[0013]
On the other hand, the initial tensile resistance when the cord is in the raw cord state is 158.0 g / de, and the initial tensile resistance after dipping is 190.2 g / de . For example, the cord is made of PET. In the case of the conventional V-ribbed belt, since the initial tensile resistance is higher than that of about 100 g / de, the elongation of the belt accompanying traveling is suppressed to a small level. If the initial tensile resistance is less than 150 g / de, a transmission belt having a good dimensional stability cannot be obtained since it exerts an adverse effect on the elongation during running after the belt is attached. On the other hand, if the initial tensile resistance exceeds 500 g / de as in the case of a conventional V-ribbed belt whose core is made of aramid fibers, for example, vibration noise may be generated during belt running. It is hard to say that it is an excellent transmission belt.
[0014]
According to a second aspect of the present invention, the transmission belt is a V-ribbed belt for driving an accessory of an automobile.
[0015]
According to a third aspect of the present invention, the transmission belt is used in a belt drive device (belt drive system) of a serpentine drive provided with an auto tensioner for keeping the belt tension constant.
[0016]
According to a fourth aspect of the present invention, there is provided a serpentine drive belt used for driving an auxiliary machine of an automobile, comprising a V-ribbed belt having a rubber layer in which a core wire is embedded, and an auto tensioner for keeping the tension of the V-ribbed belt constant. The core wire of the V-ribbed belt in the belt drive device is made of a twisted polyethylene-2,6-naphthalate fiber, and has an initial tensile resistance when the core wire is in a raw cord state. 158.0G / a de, and an initial tensile resistance degree after dipping the core wire a 190.2g / de, initial tensile resistance degree after dipping of the core wire, raw cord of the core wire It is characterized by being larger than the initial tensile resistance in the state.
[0017]
In the above configuration, the dimensional change of the V-ribbed belt and the belt elongation after running are both kept small by the cord. As a result, in the serpentine drive in which the V-ribbed belt is used, the working space of the auto tensioner can be reduced, and the space of the serpentine drive occupying the engine room can be reduced accordingly, and therefore the serpentine drive is adopted. Can contribute to the downsizing of the engine room.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a layout of a serpentine drive using a V-ribbed belt B as a transmission belt according to an embodiment of the present invention. In the figure, reference numeral 11 denotes a pulley that is rotatably connected to an engine crankshaft. Around the pulley 11, an alternator pulley 12, a power steering pump pulley 13, an idler pulley 14, and a water pump A pulley 15 and an air conditioner pulley 16 are arranged on the same plane. A single V-ribbed belt B is wound around the pulleys 11 to 16 so that the belt B can run, and an auto tensioner for keeping the tension of the belt B constant is disposed.
[0019]
The auto tensioner has a belt pressing pulley 17 at the distal end of an arm pivotally supported at the base end so as to be rotatable around an axis orthogonal to the plane of arrangement of the pulleys 11 to 16. The spring is always urged to rotate in the belt pressing direction P, while the belt B is damped by rotating in the direction Q opposite to the belt pressing direction P so that a predetermined tension is quickly applied to the belt B when the belt tension decreases. In addition, fluttering of the belt B can be suppressed when the belt tension rapidly increases.
[0020]
The following six are required for the auto tensioner.
(1) Stable maintenance of belt tension (stable maintenance of spring characteristics).
(2) Maintaining stable damping characteristics.
(3) Miniaturization.
(4) Low price.
(5) Low noise performance.
(6) Proper alignment.
[0021]
Among the above, regarding the downsizing of (3), as shown in comparison with FIGS. 3 (a) and 3 (b), if the same belt winding angle and the same belt tension F (axial load) are required, From the torque characteristics, the shorter arm length shown in FIG. 4B requires a smaller torsional torque (F × L << F × l), so that the size and weight can be reduced.
[0022]
As shown in an enlarged view in FIG. 1, the V-ribbed belt B includes an adhesive rubber layer 1 and a rib rubber layer 3 integrally laminated on the bottom surface side (the lower surface side in FIG. 1) of the adhesive rubber layer 1. Yes. These rubber layers 1 and 3 are made of a known rubber such as NR, CR, H-NBR, A-CSM or the like. The core 2 is embedded in the adhesive rubber layer 1 in a spiral shape so as to extend substantially in the belt length direction and line up at a predetermined pitch interval in the belt width direction. On the other hand, on the bottom side of the rib rubber layer 3, three ribs 4, 4,... Provided so as to extend in the belt length direction are formed so as to be arranged at predetermined pitch intervals in the belt width direction. ing. The rib rubber layer 3 is mixed with short fibers 5, 5,... Such as natural fibers, polyester, polyamide, etc. oriented in the belt width direction, so that the overall hardness of the rib rubber layer 3 is bonded. It is higher than the rubber layer 1. A bias canvas 6 woven with weft and weft yarns made of polyester, polyamide, aramid, cotton or the like is attached to the back side of the adhesive rubber layer 1 (upper surface side in the figure). Here, the said adhesive rubber layer 1 and the rib rubber layer 3 comprise the belt main body in this invention.
[0023]
In this embodiment, the core wire 2 is made of a cord made of PEN (polyethylene-2,6-naphthalate fiber). At that time, the core wire 2 has a dry heat shrinkage rate at 150 ° C. and a raw cord that has not yet been subjected to dip treatment or the like as described in the section “Means for Solving the Problems”. The shrinkage stress during dry heat is 1.0% or less and 0.2 g / de or less, respectively, while the initial modulus (initial tensile resistance) is 150 to 500 g / de. That is, the initial tensile resistance degree when the raw cord state of core wire is in 158.0 g / de, and an initial tensile resistance degree after dipping the cord is in the 190.2g / de, the core wire The initial tensile resistance after dipping is greater than the initial tensile resistance when the cord is in the raw cord state.
[0024]
Therefore, according to this embodiment, in the core wire 2 of the V-ribbed belt B, the dry heat shrinkage rate and the dry heat shrinkage stress at 150 ° C. are suppressed to 1.0% or less and 0.2 g / de or less, respectively. As a result, the dimensional change of the belt B itself at the time of storage can be reduced, and the initial modulus is increased to 150 to 500 g / de. Since the belt elongation due to can be reduced, the working space of the tensioner in the serpentine drive can be greatly reduced when used in the serpentine drive. Therefore, the space occupied by the serpentine drive in the engine room can be reduced, and the adoption of the serpentine drive can greatly contribute to the reduction in the size of the engine room and the overall weight.
[0025]
In the above-described embodiment, the case where the transmission belt is a V-ribbed belt has been described. However, the transmission belt may be a belt that is required to have excellent dimensional stability to the same extent as described above. It is not limited to the V-ribbed belt.
[0026]
-Experimental example-
Next, an experiment conducted for verifying the effect of the core wire will be described. First, as Invention Example 1 and Comparative Examples 1 and 2, the belt outer circumference length is 2260 mm using PVA (part number is different from each other) in Comparative Examples 1 and 2 and PEN in Invention Example 1 respectively. A ribbed belt was produced.
[0027]
In Comparative Example 1, the dry heat shrinkage rate and the dry heat shrinkage stress were 0.3% and 0.07 g / de, respectively, while the initial modulus was 340.7 g / de. When this was dipped, the dry heat shrinkage and dry heat shrinkage stress were 0.4% and 0.29 g / de, respectively, while the initial modulus was 379.2 g / de.
[0028]
In Comparative Example 2, the dry heat shrinkage rate and the dry heat shrinkage stress were 0.5% and 0.15 g / de, respectively, while the initial modulus was 291.8 g / de. When this was dipped, the dry heat shrinkage and the dry heat shrinkage stress were 0.4% and 0.27 g / de, respectively, and the initial modulus was 377.8 g / de.
[0029]
In Invention Example 1, the dry heat shrinkage rate and dry heat shrinkage stress were 0.9% and 0.14 g / de, respectively, while the initial modulus was 158.0 g / de. When this was dipped, the dry heat shrinkage and the dry heat shrinkage stress were 1.0% and 0.30 g / de, respectively, while the initial modulus was 190.2 g / de. In addition, the structures of the yarns of Invention Example 1 and Comparative Examples 1 and 2 are both 1000 de / 2 × 3, and the number of upper twists and the number of lower twists are substantially the same. The processing temperature, processing time, and tension during the dip processing are also the same conditions.
[0030]
With respect to the above invention example 1 and comparative examples 1 and 2, the belt time-dependent dimensional change [%] and the belt elongation after running [%] were measured, respectively. Specifically, the dimensional change of the belt over time corresponds to storage for a predetermined time (1097 to 2980 hours [7 to 8 LN hours]) under a constant atmospheric temperature (40 ° C. in this example). This was examined by the change in the belt outer circumference when the test was performed. On the other hand, the belt elongation after running was examined by the elongation when running for a predetermined time in the serpentine drive shown in FIG.
[0031]
For comparison, as shown in the following Table 1, each is made of PET, and when the raw cord is used, the dry heat shrinkage rate and the dry heat shrinkage stress are 1.0% and 0.2 g, respectively. V-ribbed belts as Comparative Examples 3 to 6 were prepared using the core wires having an initial modulus of less than 150 g / de, while measuring the same items as above. Then, the elapsed time + running dimension change rate was calculated. Of these Comparative Examples 3 to 6, Comparative Example 3, Comparative Example 5 and Comparative Example 6 have the same product number, and only Comparative Example 4 has a different product number. Moreover, the structure of the yarn and the number of twists are the same as those in the above-mentioned Invention Example 1 and Comparative Examples 1 and 2. However, the dip process is slightly different except that the comparative example 4 is the same as the case of the above-described invention example 1 and comparative examples 1 and 2. That is, in both Comparative Examples 3 and 5, the tension is slightly higher, in Comparative Examples 3 and 6, the processing time is about half, and in Comparative Example 3, the processing temperature is slightly lower.
[0032]
The above results are also shown in Table 1. Further, the dimensional change with time of the belt is also shown in FIG.
[0033]
[Table 1]

[0034]
Considering the result of the time elapsed + running dimensional change rate, as can be seen from Table 1 above, the invention example 1 and the comparative examples 1 and 2 both stay on the 0.6% level, while the comparative example. In 3-6, even a small one (Comparative Examples 3 and 4) is in the 0.7% range, and in Comparative Example 6, it reaches 1.11%. This is because, as can be seen from, for example, Comparative Examples 3 and 5, even if the belt elongation after running is smaller than those of Invention Example 1 and Comparative Examples 1 and 2, the value of the belt aging change is larger than that. .
[0035]
Furthermore, when Invention Example 1 and Comparative Example 2 are compared, it can be seen that in the case of Invention Example 1, good dimensional stability can be obtained even if the initial modulus is a little over 150 g / de. In this regard, the inventors set the lower limit of the initial modulus higher in the case of PVA (Comparative Examples 1 and 2) than in the case of PEN (Inventive Example 1) (for example, about 300 g / de). I think it is necessary.
[0036]
On the other hand, considering Comparative Examples 3 to 6, for example, even in the case of Comparative Examples 3 and 5, even if the belt elongation after running can be reduced by increasing the tension during the dipping process, the dimensional change of the belt over time is conversely Because of deterioration, simply changing the conditions of the dip process leaves the characteristics (dry heat shrinkage rate, shrinkage stress during dry heat and initial modulus) of the raw cord and greatly improves dimensional stability. It turns out to be difficult to do.
[0037]
In other words, if the characteristic values of the dry heat shrinkage rate, the shrinkage stress during dry heat, and the initial modulus are kept, the dimensional change of the belt over time and the belt elongation after running can be achieved regardless of the difference in conditions such as dip treatment. It can be seen that both can be kept small and that overall excellent dimensional stability can be imparted to the belt.
[0038]
【The invention's effect】
As described above, according to the first to fourth aspects of the present invention, it is possible to reduce variations in dimensions at the time of finishing the belt, changes in the size of the belt over time during storage, and to reduce belt elongation due to running. Therefore, a transmission belt having excellent dimensional stability can be provided.
[0039]
In particular, according to the second to fourth aspects of the present invention, since the transmission belt is a V-ribbed belt, in the serpentine drive in which the V-ribbed belt is used, the working space of the tensioner for keeping the belt tension during running is constant. The space of the serpentine drive occupying the engine room can be reduced accordingly. Therefore, the adoption of the serpentine drive can contribute to the reduction in size and weight of the engine room.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a basic configuration of a V-ribbed belt according to an embodiment of the present invention cut along a plane perpendicular to the belt length direction.
FIG. 2 is a schematic diagram showing a layout of a serpentine drive.
FIG. 3 is a schematic diagram for explaining the magnitude of torsional torque depending on the arm length in the auto tensioner.
FIG. 4 is a characteristic diagram showing a change in belt outer peripheral length over time under storage at a constant atmospheric temperature.
[Explanation of symbols]
1 Adhesive rubber layer (belt body)
2 Core wire 3 Rib rubber layer (belt body)
4 ribs B V-ribbed belt (power transmission belt)

Claims (4)

A power transmission belt having a rubber layer in which a core wire is embedded;
The core wire is made of a twisted polyethylene-2,6-naphthalate fiber, the initial tensile resistance when the core wire is in a raw cord state is 158.0 g / de, and the core wire is dipped The initial tensile resistance after 190.2 g / de, and the initial tensile resistance after dipping of the core wire is larger than the initial tensile resistance when the core wire is in a raw cord state. A transmission belt.   2. The power transmission belt according to claim 1, wherein the power transmission belt is a V-ribbed belt for driving an auxiliary machine of an automobile.   3. The power transmission belt according to claim 1, wherein the power transmission belt is used in a belt drive device of a serpentine drive provided with an auto tensioner for keeping the belt tension constant. A serpentine drive belt drive device comprising a V-ribbed belt having a rubber layer with a core wire embedded therein and an auto tensioner that keeps the tension of the V-ribbed belt constant, and used for driving an auxiliary machine of an automobile,
The core wire of the V-ribbed belt is made of twisted polyethylene-2,6-naphthalate fiber , and has an initial tensile resistance of 158.0 g / de when the core wire is in a raw cord state. The initial tensile resistance after the dip treatment is 190.2 g / de, and the initial tensile resistance after the dip treatment of the core wire is larger than the initial tensile resistance when the cord is in the raw cord state. A belt drive device characterized by that.

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