JPH0559012U - Power transmission belt - Google Patents

Abstract

(57) [Summary] [Purpose] In a power transmission belt having a V-shaped compression layer, the material is changed in the aramid short fibers mixed in the compression layer in order to obtain wear resistance and lateral pressure resistance. In addition, abrasion resistance and lateral pressure resistance are secured in the belt compression layer portion, and at the same time, the friction noise (rubbing noise) generated when the belt of this type is hung on the pulley and run is also suppressed. [Structure] Face-to-face friction drive surface (6) (6) is compressed layer (5)
In the V-ribbed belt (1) provided in the section, the aramid short fibers (9), which are easily fibrillated, are mainly contained in the tip forming portion (7) near the tip of the compression layer (5), and the compression layer (5) The aramid short fibers (10), which are difficult to fibrillate, are embedded in the basic constituent part (8), which is the remaining part, while maintaining their orientation in the belt width direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a power transmission belt, and in particular, by embedding a group of short fibers in a compression layer portion that constitutes the belt, the wear resistance and lateral pressure resistance of the belt compression portion are improved to improve power transmission efficiency. The present invention relates to a belt for power transmission.

[0002]

[Prior Art]

 The power transmission belt, in particular, the V-shaped compression layer portion located on the lower surface side of the belt is fitted in the V-shaped groove of the pulley, and the pair of exposed facing friction drive surfaces of the belt compression layer portion are connected to the V-shaped groove of the pulley. V-ribbed belts, low-edge V-belts, and cogged V-belts are known as belts that travel while being pressed against a surface to transmit power.

Each of these belt groups runs while being wound around a pulley provided with a V-shaped groove, but both side portions of the folded belt, especially the compression layer portion constituting the lower portion of the belt, are subjected to strong side pressure. In response to this, the compression portion is deformed and worn, and both of these greatly hinder efficient and smooth power transmission over a long period of time. In order to prevent these adverse effects derived from the belt compression layer portion, a means for embedding a short fiber group in the belt compression layer portion while maintaining the orientation in the belt width direction has been widely adopted. An aramid short fiber (aromatic polyamide fiber) is used as a short fiber having excellent wear resistance and lateral pressure resistance (see, for example, Japanese Utility Model Laid-Open No. 54-162055).

[0004]

[Problems to be solved by the device]

 By embedding a aramid short fiber group with excellent wear resistance and lateral pressure resistance in the compression layer of the belt, we found that the wear resistance and lateral pressure resistance of the area improved remarkably. The embedded aramid fiber is too rigid, so when the belt enters the pulley or comes out of the pulley, the contact resistance between the belt and the pulley is large, which causes annoying scratching noise while the belt is running ( Rubbing noise) was generated, and this point was left as an issue to be solved. If the short fiber group is intentionally thinned in order to reduce the rigidity of the aramid fiber in order to eliminate the generation of this rubbing sound, it will be entangled with each other when the short fiber is mixed in the rubber-like elastic body, which is preferable. A new problem was observed that the orientation could not be obtained.

The rubbing noise that increases with the rigidity imparted to the belt compression layer portion is largely due to the contact between the tip of the compression layer portion of the belt, that is, the inner peripheral surface portion of the belt and the pulley. The idea is to effectively utilize the rigidity possessed by aramid short fibers, while at the same time changing the rigidity of the compression layer part of the belt to provide sufficient wear resistance and lateral pressure resistance to the belt compression layer part. An object of the present invention is to provide a power transmission belt capable of suppressing the generation of the annoying rubbing noise while securing the belt.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the power transmission belt according to the present invention adopts the following configuration. That is, in a power transmission belt having a face-to-face friction drive surface in a V-shaped compression layer portion constituting a belt, a short aramid fiber group that easily fibrillates is formed in the tip portion portion of the compression layer portion near the tip portion. The main component is the aramid short fiber group that is difficult to fibrillate in the basic constituent part, which is the remaining part of the compression layer, and the aramid short fibers of different materials are oriented in the belt width direction in each constituent part of the compression layer part. It is characterized by being kept and buried. Further, when the height of the tip forming portion is h and the height of the entire belt compression layer portion is H, the height h of the tip forming portion is set in the range of 0.2H ≦ h <0.5H. It is characterized by

[0007]

[Action]

 With the configuration of this invention, a large amount of aramid short fiber groups that are particularly prone to fibrillation are formed in the tip configuration part of the compression layer part of the belt, which is the main occurrence point of the rubbing noise (rubbing noise) generated between the pulley and the belt. By mixing and fibrillating the aramid short fiber group while the belt is running, the short fiber group on the lower surface side of the belt compression layer is torn and becomes thin, and the rigidity that it holds decreases and the belt enters the pulley. Also, the slip-out becomes smooth, and the generation of excessive scratching noise is suppressed. On the other hand, by adding a large amount of aramid short fibers, which are difficult to fibrillate, to the basic constituent part, which is the remaining part of the compression layer part, the wear resistance and lateral pressure resistance of the belt compression layer part are maintained for a long period of time.

[0008]

【Example】

 Next, a concrete example of the power transmission belt according to the present invention will be described with reference to the drawings while taking an example of a V-ribbed belt, which is one of the power transmission belts having a facing friction drive surface in the compression portion layer of the belt. explain. As is well known, the V-ribbed belt (1) is embedded with a low-elongation, high-strength tensile rope (3) made of upper surface cover cloth (2), polyester fiber, nylon fiber, aromatic polyamide fiber, etc. from above. Cushion rubber layer (4), consisting of a group of V-shaped ribs (5) extending parallel to the longitudinal direction of the belt forming the compression layer of the belt that fits with the V-shaped grooved pulley on the lowermost surface ..

The belt ribs (5), which have facing friction driving surfaces (6) and (6) on both sides and are fitted into the V-shaped grooves of the pulleys, respectively have the same NR and SBR as the cushion rubber layer (4). 5 to 50 parts by weight of short fibers per 100 parts by weight of rubber material in a single material composed of butadiene rubber, chloroprene rubber, chlorosulfonated polyethylene, water-added NBR, etc. The group of the short fibers is embedded while maintaining the orientation in the width direction of the belt. In this short fiber group, 80% or more of the whole is composed of aramid short fibers in particular, and further, the aramid fibers are so-called aramid short fibers and fibrils in which filaments are likely to be split and thinned in the longitudinal direction. It is differentiated into aramid short fibers that are difficult to convert.

To explain this more concretely, polyaraphenylene terephthalamide can be mentioned as an aramid fiber which is easily fibrillated, and in general, Kevlar (trade name of DuPont, USA) and Twaron (Enca, Netherlands) There is a product name). An example of the aramid fiber that is difficult to fibrillate is polymetaphenylene isophthalamide, which is generally Cornex (trade name of Teijin Limited in Japan).

As described above, the two types of aramid short fibers having different materials are remarkably different in the compounding amount in the constituent portions of the rib portions forming the compression portion of the belt. That is, the rib (5) is roughly divided into a tip forming portion (7) near the tip and a foundation forming portion (8) near the tensile body rope, and the height of the tip forming portion (7) is h. , And the total height of the ribs (5) is H, the height h of the tip forming portion (7) is set in the range of 0.2H ≦ h <0.5H. Then, the aramid short fibers (9) which are easily fibrillated are mainly contained in the tip constituent portion (7) of the belt rib portion, that is, at a ratio of 75% or more of the mixed aramid short fibers, while in the basic constituent portion (8). Aramid short fibers (10), which are difficult to fibrillate, are mainly embedded, that is, they are embedded in a proportion of 75% or more of the mixed aramid short fibers.

As described above, from the description that 80% or more of all short fibers mixed in the rib portion of the belt are aramid fibers, the main body in the tip part (7) of the rib portion is occupied. The amount of aramid staple fibers (9) that easily fibrillate with respect to all staple fibers is 0. 8 × 0.75 = 0.6, that is, 60% or more, and the amount of aramid short fibers (10), which occupy the main constituent in the basic constituent part (8) of the ribs and which is difficult to fibrillate, is also mixed in with all the short fibers. It will be 60% or more.

The technical basis for limiting the amount of short fibers mixed in the rubber material forming the rib portion of the belt within the range of 5 to 50 parts by weight is that if the amount is less than 5 parts by weight, the resistance of the belt rib portion is reduced. It lacks abrasion resistance and lateral pressure resistance. On the other hand, when the content is 50 parts by weight or more, the flexibility of the belt itself is extremely reduced.

Further, in comparison with the total height H of the rib portion (5), the height h of the tip forming portion (7) in the belt rib portion is regulated within the range of 0.2H ≦ h <0.5H. The rationale is that if the height is less than 0.2H, the height (wall thickness) of the tip forming portion (7) is too small in proportion to the entire belt rib (5), and the target rib portion forming portion (7) is ) The result is that the rigidity of the part does not fall sufficiently to the target softening value and does not contribute much to the reduction of rubbing noise (rubbing noise). On the other hand, in the case of 0.5 or more, the height (wall thickness) of the tip-constituting portion (7) of the rib portion becomes too large, and the remaining portion in the belt rib (5) portion, that is, aramid short fibers which are difficult to be fibrillated ( 10) The thickness of the basic component part (8) of the rib part containing the group is reduced accordingly, the rigidity of the entire belt rib (5) part is reduced, and the abrasion resistance and lateral pressure resistance thereof are extremely reduced. Will result.

Next, a 3PK1100 type V-ribbed belt embodying the present invention, that is, a V-ribbed belt having the same length of 1100 mm and a belt of 3 ribs and having the same shape as the conventional belt, is mainly mixed with aramid short fibers which are difficult to be fibrillated in the entire conventional belt compression layer portion. A sounding test was carried out by using a forced V-ribbed belt and varying the amount of forced slip wear and rotation.

The V-ribbed belt according to the present invention (hereinafter referred to as the embodiment belt) has an overall height of 4. 3 mm, the total height of the rib portion (compression layer portion) is set to 2.0 mm, and the height of the tip forming portion (7) forming a part of the rib portion (compression layer portion) is set to 0.5 mm. The rib portion (compression layer portion) of the belt (1) has the same basic constitution portion (8) as that of 100 parts by weight of chloroprene rubber (CR) and 4 parts of 6.6 nylon as a short fiber group. , 3 parts of Kevlar as aramid short fibers (9) that are easily fibrillated, and 13 parts of Conex as aramid short fibers (10) that are difficult to fibrillate were mixed while maintaining the orientation in the belt width direction. The tip component (7) had 100 parts by weight of chloroprene gum (CR) mixed with 4 parts of 6.6 nylon, 3 parts of Kevlar 1 and 3 parts of Conex as a group of short fibers. On the other hand, as a conventional V-ribbed belt (hereinafter, referred to as a comparative example belt), the entire compression layer is a basic component part (8) that constitutes the rib part (compression layer part) of the belt of the embodiment as described above. It has the same components.

First, a forced slip wear test was performed using the two types of belts having the above-described configurations. As shown in FIG. 2, the experimental machine is equipped with a drive pulley (Dr) having a diameter of 80 mm, a driven pulley (Dn) having a diameter of 80 mm, and a tension pulley (Ten) having a diameter of 120 mm, and these belts are sequentially mounted on the belt. 6% slip between the drive pulley (Dr) and the driven pulley (Dn) is forced, and the load of the driven pulley (Dn) is set to 1 kg · m (9.8 Nm). The drive pulley (Dr) was run for 72 hours at a rotation speed of 3000 rpm below. As a result, the difference in weight reduction between the belt weight before running and the belt weight after running for both belts was 59.40g-58.46g = 0.94g for the practical example belt, while it was for the comparative example belt. The difference between the two belts was 59.11g-58.21g = 0.90g, and there was almost no difference in the amount of wear between them. It was verified that the wear degree was not significantly generated by providing 7).

Next, a pronunciation test based on rotation fluctuation was carried out. For the schematic diagram of the experimental machine, the running-in test machine shown in Fig. 3 and the pronunciation test machine shown in Fig. 4 were used. The running-in running shown in FIG. 3 is for performing a pre-running for making the softened state of the tip end portion forming a part of the compression layer portion of the belt rib of this embodiment appear, and its outline is driving with a diameter of 120 mm. These belts are sequentially loaded between the pulley (Dr), the driven pulley (Dn) with a diameter of 120 mm, and the tension pulley (Ten) with a diameter of 70 mm, and the drive pulley (Dr) is loaded under the condition of a temperature of 85 ° C. and no load. Was run for 100 hours at a rotation speed of 4900 rpm. The belt that has completed the running-in under the above conditions is transferred to the sounding tester as the next step.

The pronunciation tester shown in FIG. 4 is outlined between a drive pulley (Dr) having a diameter of 140 mm, an idler pulley (Id) having a diameter of 116 mm, and a generator (ALT) having a pulley having a diameter of 73 mm in an unloaded state. Then, the belt after the running-in is loaded, and the fluctuation rate of rotation is 10% at room temperature, that is, the angular velocity is within ± 5% of the average during one rotation of the drive pulley (Dr). The driving pulley (Dr) was run at a rotation speed of 1,000 rpm under the condition that the temperature could change. As a result, no sound was generated in the example belts, while continuous abnormal noises with curcules were observed in the comparative belts. From this test result, the belt according to the present invention is provided with a slightly softening tip forming portion (7) at the rib tip end portion, so that the belt is softened when the belt enters or leaves the pulley. It was demonstrated that the part acts as a cushioning material when the belt is running and effectively suppresses the generation of annoying scratching noise.

[0020]

[Effect of the device]

 In this invention, the aramid short fiber which is easy to be fibrillated is mainly formed in the tip forming portion near the tip of the compression layer which forms a part of the power transmission belt fitted with the V-shaped groove of the pulley. On the other hand, the basic constituent parts are mixed with a large amount of aramid short fibers, which are different from the above materials and are hard to fibrillate, to produce a unique effect for each constituent part of the compression layer. That is, at the leading edge forming portion of the belt compression layer portion, which is the final disengagement point as well as the initial fitting point with the V-shaped groove of the pulley, the belt becomes fibrillated due to fibrillation of the aramid short fiber group with the passage of time. The short fibers on the surface side of the compression layer are torn and fragmented, reducing the rigidity of the fibers, which softens the tip component, which makes it easier for the belt to move in and out of the pulley. It was possible to prevent the generation of excessive scratching noise.

On the other hand, in the basic constituent part of the belt compression layer, by mixing the aramid short fiber group which is difficult to fibrillate, the original rigidity of the aramid short fiber is maintained for a long time, and the wear resistance and lateral pressure resistance of the belt compression layer part are maintained. As a result, it was possible to achieve a multifaceted effect on the compression layer portion of the belt by properly using the mixed short fiber group of different materials as described above.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a V-ribbed belt embodying the present invention.

FIG. 2 is a schematic front view of a forced slip abrasion tester for a belt.

FIG. 3 is a schematic front view of a running-in test machine that is executed prior to a belt sounding test.

FIG. 4 is a schematic front view of a belt pronunciation tester.

[Explanation of symbols]

 1 V-ribbed belt 5 Ribs (compression layer) 6, 6 Face-to-face friction drive surface 7 Tip component part in compression layer part 8 Basic component part in compression layer part 9 Aramid short fiber that easily fibrillates 10 Aramid short fiber that does not easily fibrillate

Claims (4)

[Scope of utility model registration request] 1. A power transmission belt having a facing friction drive surface in a V-shaped compression layer portion of the belt, wherein in the compression layer portion, a aramid short fiber group which easily fibrillates is mainly formed in a tip forming portion near a tip portion. A belt for power transmission, characterized in that the aramid short fiber group which is difficult to be fibrillated is mainly embedded in the basic constituent portion of the remaining portion of the compression layer portion while maintaining the orientation in the belt width direction. 2. The height of the tip forming portion is set to H, and the height of the tip forming portion is set to h in the compression layer portion mainly embedding the aramid short fiber group that easily fibrillates. 2. The power transmission belt according to claim 1, wherein the height h is set in a range of 0.2H ≦ h <0.5H. 3. The amount of short fibers embedded in the belt compression layer portion is in the range of 5 to 50 parts by weight with respect to 100 parts by weight of the rubber material, and both the basic constituent portion and the tip constituent portion of the compression layer portion are embedded. 80% or more of the total short fiber amount is composed of aramid short fibers. Among these aramid short fibers, the amounts of aramid short fibers that are difficult to fibrillate and aramid short fibers that are easy to fibrillate in both the base and tip components are respectively The power transmission belt according to claim 1 or 2, which has a constitution of 75% or more. 4. The power transmission according to claim 1, wherein the aramid fiber easily fibrillated is polyparaphenylene terephthalamide, and the aramid fiber hardly fibrillated is polymetaphenylene isophthalamide. belt.