JP2000337451A - Transmission belt and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve belt performance by improving the surface shape of a V-rib of a transmission belt with its a short fiber group protruded from the side of the V-rib. SOLUTION: An aramid short fiber 8 and a non-aramid synthetic fiber 38 are protruded from the side 11 of a V-rib. The protrusion part 15 of the aramid short fiber 8 is formed in a curled state. The protrusion part 40 of the synthetic fiber 38 is formed in the shape of a fan spreading toward a tip with a non- melting state kept. The roots of the two protrusion parts 15 and 40 are erected from the side 11 of the V-rib. The surface shape of the side 11 is formed in a wind-wave shape so that a microuneven surface is formed in the side 11 of the V-rib.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power transmission belt and a method of manufacturing the same, and more particularly to a power transmission belt such as a V-ribbed belt or a V-belt in which short fibers are mixed in a bottom rubber portion, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Publication No.
No. 7, JP-A-7-4470, etc., to improve the lateral pressure resistance and wear resistance of a friction transmission portion of a belt and to prevent generation of abnormal noise during belt running. A power transmission belt is known in which a short fiber group is mixed into a bottom rubber portion while maintaining the orientation in the belt width direction, and a part of the short fiber group is projected from the surface of the bottom rubber portion. I have.

[0003]

However, if the protruding length of the short fiber from the surface of the bottom rubber portion is too long, the characteristics of the belt will fluctuate greatly when the protruding portion is reduced by abrasion. Therefore, considering that the predetermined belt characteristics are maintained for a long period of time, there is a limit to the amount of protrusion of the short fibers. Therefore, means for dramatically improving the performance of the belt by improving the bottom rubber portion as well as the short fiber has been desired.

[0004] The present invention has been made in view of such a point, and an object of the present invention is to improve belt performance by improving the surface shape of a bottom rubber portion.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an uneven surface on the bottom rubber portion to increase its surface area.

[0006] Specifically, the transmission belt according to the present invention comprises:
A transmission belt in which a group of short fibers is mixed into a bottom rubber portion so as to be oriented in a predetermined direction, and a part of the short fiber group protrudes from the surface of the bottom rubber portion. It is to be formed in an uneven shape.

According to the above, the surface area of the bottom rubber portion is increased due to the unevenness of the surface of the bottom rubber portion.
Therefore, the performance of the belt is improved. Further, a gap is easily formed on the contact surface with the pulley, and even if water or the like enters between the belt and the pulley, water or the like can be dispersed or discharged through the gap. The resistance stabilizes.

The unevenness on the surface of the bottom rubber portion may be formed in a wind wave shape. Thereby, a suitable uneven shape is formed on the surface of the bottom rubber portion.

[0009] The surface of the bottom rubber portion has a height difference of 0.5
It is preferable that the thickness be from 10 μm to 10 μm. Thereby, a suitable uneven shape is formed on the surface of the bottom rubber portion.

[0010] A method of manufacturing a power transmission belt according to the present invention is a method of manufacturing a power transmission belt in which a surface of a bottom rubber portion is formed in an uneven shape and short fibers protrude from the surface of the bottom rubber portion. The method includes a step of grinding a bottom rubber portion in which short fiber groups are mixed so as to be oriented in a predetermined direction by a grindstone having superabrasive grains having a protruding 50% to 95% of the abrasive grain size. It is.

According to the above-mentioned matter, since the protruding amount of the superabrasive grains is large, it is easy to form the surface of the bottom rubber portion in an uneven shape. Further, contact between the bond portion of the grindstone and the bottom rubber portion of the belt is prevented, and generation of frictional heat is suppressed.

Another method of manufacturing a power transmission belt according to the present invention is a method of manufacturing a power transmission belt in which a surface of a bottom rubber portion is formed in an uneven shape and short fibers protrude from the surface of the bottom rubber portion. Then, the bottom rubber portion mixed so that the short fiber group is oriented in a predetermined direction is reduced to an abrasive density of 3.5% to 55%.
And a step of grinding with a grindstone having superabrasive grains.

According to the above, since the abrasive density of the superabrasive grains is low, it is easy to form the surface of the bottom rubber portion into an uneven shape. In addition, since the chip pocket of the superabrasive becomes large and the grinding chips are easily discharged, clogging with the chips hardly occurs.

Another method of manufacturing a power transmission belt according to the present invention is a method of manufacturing a power transmission belt in which a surface of a bottom rubber portion is formed in an uneven shape and short fibers protrude from the surface of the bottom rubber portion. Then, the super-abrasive grains in which 50% to 95% of the abrasive grain size protrudes and the abrasive grain density is 3.5% to 55% are mixed with the bottom rubber portion mixed so that the short fiber group is oriented in a predetermined direction. And a step of grinding with a grindstone.

According to the above-mentioned matter, since the amount of projection of the superabrasive grains is large and the density of the abrasive grains is small, it is extremely easy to form the surface of the bottom rubber portion in an uneven shape. Further, contact between the bond portion of the grindstone and the bottom rubber portion of the belt is prevented, and generation of frictional heat is suppressed. In addition, since the abrasive grain density is small, the chip pocket becomes large, and the grinding chips are easily discharged. Therefore, clogging due to cutting chips is less likely to occur.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a sectional shape of a transmission belt 10 according to the present embodiment. The transmission belt 10 is a V belt used for a driving device of an auxiliary device of an automobile and other general industrial uses.
It is a ribbed belt.

Tensile members 2 extending in the belt length direction are embedded in the adhesive rubber layer 4 at regular intervals in the belt width direction (the left-right direction in FIG. 1). On the upper surface side of the adhesive rubber layer 4, that is, on the outer surface side of the belt, a canvas layer 5 is provided. On the lower surface side of the adhesive rubber layer 4, that is, on the inner surface side of the belt, a plurality of V-ribs 7 extending in the belt length direction are provided in the belt width direction. The V-rib 7 corresponds to a “bottom rubber portion” in the present invention. The adhesive rubber layer 4 and the V rib 7 can be formed from, for example, chloroprene rubber, H-NBR rubber, CSM rubber, natural rubber, SBR rubber, butadiene rubber, EPM, EPDM, or the like.

A plurality of aramid short fibers 8,8,
... and non-aramid synthetic fibers 38, 38, ... are mixed while maintaining the orientation in a predetermined direction. Specifically, in the present embodiment, the aramid short fibers 8 and the synthetic fibers 38 other than aramid are embedded in the V-ribs 7 while maintaining the orientation in the belt width direction (the left-right direction in FIG. 1).

The aramide short fibers 8 may be para-aramid fibers or meta-aramid fibers. That is, polyparaphenylene isophthalamide or polymetaphenine isophthalamide can be used. Specifically, Kevlar (trade name of DuPont), Technora (trade name of Teijin Limited), Toalon (trade name of Enca), etc. can be used as the para-aramid fiber. Nex (trade name of Teijin Limited), Nomex (trade name of DuPont) and the like can be used. As the synthetic fiber 38, for example,
Nylon, vinylon, polyester or the like having a filament diameter of 20 μm or more can be suitably used.

As shown in FIGS. 2 and 3, the surface 11 of the V-rib 7 has microscopic irregularities (for example, a height difference of 0.5 μm to 0.5 μm).
10 μm). In this embodiment,
The unevenness is formed in a shape such that a plurality of waves travel in one direction by receiving a wind, that is, a wind wave shape. The shape of the unevenness is not limited to the wind wave shape. For example, as shown in FIG. 4, the unevenness 46 in which the peaks and the valleys appear alternately or other unevennesses may be used. Of course.

As shown in FIGS. 2 and 3, a part of the aramid short fiber groups 8, 8,... Buried in the V rib 7 protrudes from the side surface 11 of the V rib 7. Projection 1 of each aramid short fiber 8
5 is curved to increase the apparent surface area per unit protrusion height. However, aramid short fiber group
The projections 15, 15, ... of 8, 8, ... are not all curved in the same direction, but are irregularly curved in multiple directions. As described above, the aramid short fiber groups 8, 8,... Are dispersed and curved in various directions, so that the lateral pressure resistance and the wear resistance of the V-ribbed belt 10 are uniformly improved in any direction. ing. Thus, the direction dependency of the belt is reduced, and the V-ribbed belt 10 exhibits almost the same performance in any running direction.

As shown in FIG. 3, the base 12 of the protruding portion 15 of the aramid short fiber 8 stands from the side surface 11 of the V-rib 7. In other words, the aramid short fibers 8 are almost upright with respect to the side surface 11 of the V-rib 7. Projection 15
Is curved from the root 12. The distal end portion 14 of the protruding portion 15 is curved in a direction different from the bending direction of the intermediate portion 13. For example, in the aramid-based short fiber 8 shown in FIG.
The tip portion 14 is curved in a direction opposite to the direction in which the intermediate portion 13 is curved. In other words, the aramid short fibers 8 are formed in a so-called curled shape that bends in a predetermined direction from the root toward the tip and then curves in the opposite direction. As described above, the protrusion 15 of the aramid-based short fiber 8 is
The rib 7 is formed so as to be lifted from the side surface 11 and has a curl shape, so that it has a restoring force like a leaf spring.

The aramid-based short fibers 8, 8,... Have a flattened shape or have a crack at the tip due to the pressure (mechanical force) of the grindstone 21 during the later-described grinding. Things are also included.

The synthetic fiber groups 38, 38,.
Also protrude from the side surface 11 of the V-rib 7. However, the projections 40, 40, ... of the synthetic fiber groups 38, 38, ... are inclined in a certain direction, unlike the projections 15, 15, ... of the aramid-based short fiber groups 8, 8, .... Specifically, each protruding portion 40 is inclined in a direction opposite to the wave front 45 of the side surface 11 of the V-rib 7 formed in a wind wave shape. The protruding portion 40 of the synthetic fiber 38 is formed in a fan shape that is divergent toward the tip, and is flat. The corners of the sector are rounded and formed into a smooth curved surface. Further, the protruding portion 40 of the synthetic fiber 38 is maintained in a non-molten state, and its tip is formed in a wavy shape.

As shown in FIG. 3, the protrusion 40 of the synthetic fiber 38
Also stands from the side surface 11 of the V-rib 7. Thereby, apart from the micro unevenness formed on the side surface 11 of the V-rib 7, each protruding portion 15,
Microscopic irregularities are formed in which 40 is a convex portion and a buried portion of each short fiber 8, 38 is a concave portion.

Next, a method for manufacturing the V-ribbed belt 10 will be described.

First, an unvulcanized rubber sheet serving as the adhesive rubber layer 4, a cord serving as the tensile member 2, an unvulcanized rubber sheet obtained by mixing an aramid-based short fiber group and a synthetic fiber group, and the like are sequentially laminated. Is heated and vulcanized to obtain a cylindrical belt molded product.

Thereafter, as shown in FIG. 5, the belt molding 19 is moved to the main roll 22 and the tension roll 23 of the drive mechanism 20.
And run by the drive mechanism 20.
24A is a guide roll. Then, while the grindstone 21 is rotationally driven and pressed against the running belt molded body 19, the belt molded body 19 is ground. At this time, the aramid-based short fiber 8 is hard to be cut because of its large Greig tensile modulus, and a part thereof protrudes relatively long from the side surface 11 of the V-rib 7. Further, a part of the synthetic fibers 38 also protrudes in a state where the synthetic fibers 38 are inclined in a direction opposite to the belt running direction. Thus, the aramid-based short fibers 8 and the synthetic fibers 38
Performs plastic deformation by releasing stress generated on the surface of the fiber due to interference with abrasive grains. And V
On the surface of the rib 7, a wind wave-like uneven shape is formed such that the wave front 45 is directed in the rotation direction of the grindstone 21.

At this time, by adjusting the kind of the grindstone 21 and the pressing force of the grindstone 21, the protrusion shape of the aramid-based short fibers 8 and the synthetic fibers 38 and the irregular shape of the surface of the V-rib 7 are adjusted. Is possible.

As the grinding wheel 21, a disk-shaped grinding wheel 25 is used.
It is preferable to use a structure in which the diamond abrasive grains 24 are fixed to the peripheral surface by electroplating, brazing, baking or the like. However, the abrasive grains are not limited to diamond abrasive grains, and other superabrasive grains such as CBN can be used. FIG. 6A is a diagram in which a part of the peripheral surface of the grindstone 21 is projected from the vertical direction, and FIG.
FIG. 3A is a sectional view taken along line AA of FIG. As shown in FIGS. 6A and 6B, an adhesive (metal bond, nickel bond, or the like) is thinly stretched and applied on the peripheral surface of the grinding wheel 25 (see FIG. 5). A part 26 is formed.

The diamond abrasive grains 24 are evenly arranged on the bonding portion 26 and adhered. The particle size of abrasive grains 24 is #
30 to # 200 are preferable, and in this embodiment, they are set to # 140. The protruding amount of the abrasive grains 24 from the bond portion 26 is
Preferably, the height is set to 50% to 95% of the total height of the abrasive grains 24. In this embodiment, the protrusion amount of the abrasive grains 24 is set to 80%. The abrasive density of the abrasive grains 24 (the ratio of the surface area of the abrasive grains to the ground surface) is preferably 3.5% to 55%, and is set to 45% in the present embodiment.

In the grinding process, five grinding wheels 25
It is preferable to rotate at a peripheral speed of 00 to 2000 m / min, and in this embodiment, the peripheral speed is set to 1000 m / min. The grinding speed ratio Vs / Vw, which is the ratio of the peripheral speed Vw of the belt to the peripheral speed Vs of the grindstone 21, is preferably 0.002 to 0.04, and was set to 0.004 in the present embodiment.

-Effects of this embodiment- As described above, according to the present V-ribbed belt 10, the V-rib 7
The micro ribs are formed on the side 11 of the
The rubber surface area in 7 is large. Therefore, the surface pressure acting on the rubber can be reduced. Therefore, abrasion of the rubber is suppressed, the sliding characteristics of the belt are improved, and the life of the belt is prolonged.

Generally, when water, oil, or the like enters between the pulley and the belt, the sliding resistance of the belt becomes unstable. However, according to the present V-ribbed belt 10, a microscopic unevenness is formed on the side surface 11 of the V-rib 7, so that a minute gap is formed between the pulley and the belt. Therefore, water and the like are dispersed in these gaps and are easily discharged through these gaps, so that the sliding resistance is stabilized.

Since the aramid short fibers 8 and the synthetic fibers 38 protrude from the side surface 11 of the V-rib 7, the V-rib 7 itself is hardly worn and its surface is hardly flat. Therefore, the above-mentioned effect by making the surface uneven can be exhibited over a long period of time.

Further, since irregularities are formed on the side surface 11 of the V-rib 7 in advance, even if the V-rib 7 itself wears out due to long-term use, the above-mentioned effects are exerted until the irregularity becomes flat. It is expected to continue. Therefore, the V-ribbed belt 10 can maintain high performance for a long period of time.

-Performance Comparison Example-Next, a performance comparison test in which a belt (comparative example) in which the side surface 11 of the V-rib 7 is not provided with irregularities and the present V-ribbed belt 10 will be described. In the performance test, as shown in FIG. 7, a weight having a weight W is hung down on the sample belt 32 via the guide roller 33, and the load cell value of the load cell 31 is detected, whereby the tension T1 on the tension side of the belt and the tension on the loose side are detected. Tension T2
And a friction force was calculated from these ratios (tension ratios) T1 / T2.

As a result, as shown in FIG. 8, it was found that the friction force of the V-ribbed belt 10 was about 25% smaller than that of the comparative example. In addition, when a similar test was performed with moisture interposed between the pulley and the belt, as shown in FIG. 9, the V-ribbed belt 10 had a frictional force 3 times greater than that of the comparative example.
It was found to be about 0% smaller.

-Modifications- The application of the present invention is not limited to the above-described V-ribbed belt 10, but may be another type of V-ribbed belt. For example, a combined V-ribbed belt 10A as shown in FIG. 10 may be used. Further, another transmission belt such as a V-belt may be used.

[0041]

As described above, according to the present invention, since the surface of the bottom rubber portion is formed in an uneven shape, the surface area of the bottom rubber portion increases. Therefore, the sliding resistance is stabilized. Further, even if water or the like enters between the belt and the pulley, the water or the like is dispersed or discharged through the gap created by the unevenness of the surface of the bottom rubber portion, so that the sliding resistance is stabilized. Therefore, the performance of the belt is improved.

By forming the irregularities on the surface of the bottom rubber portion in a wind wave shape, a suitable irregular shape can be formed on the surface of the bottom rubber portion. Further, the height difference between the irregularities is 0.5 μm to 1 μm.
By forming it to have a thickness of 0 μm, a suitable uneven shape can be realized.

The bottom rubber portion, in which the short fiber groups are mixed so as to be oriented in a predetermined direction, is ground with a grindstone having superabrasive grains protruding from 50% to 95% of the abrasive particle diameter, thereby obtaining the bottom rubber portion. Can easily be formed in an uneven shape.
Further, contact between the bond portion of the grindstone and the bottom rubber portion of the transmission belt can be prevented, and generation of frictional heat can be suppressed. Thereby, it becomes easier to form an uneven shape on the surface of the bottom rubber portion.

The bottom rubber portion, in which the short fiber group is mixed so as to be oriented in a predetermined direction, is ground with a grindstone having superabrasive grains having an abrasive grain density of 3.5% to 55%, thereby obtaining the bottom rubber portion. Can easily be formed in an uneven shape. In addition, a large chip pocket of abrasive grains can be ensured, and clogging of grinding chips can be suppressed. Thereby, it becomes easier to form an uneven shape on the surface of the bottom rubber portion.

The bottom rubber portion mixed so that the short fiber group is oriented in a predetermined direction is formed by super-abrasive grains having an abrasive grain diameter of 50% to 95% protruding and an abrasive grain density of 3.5% to 55%. The surface of the bottom rubber portion can be very easily formed into an uneven shape by grinding with a grindstone having the following. Further, contact between the bond portion of the grindstone and the bottom rubber portion of the transmission belt can be prevented, and generation of frictional heat can be suppressed. Also,
A large chip pocket for abrasive grains can be ensured, and clogging of grinding chips can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a V-ribbed belt according to an embodiment.

FIG. 2 is an enlarged view of a surface of a V-rib.

FIG. 3 is an enlarged sectional view near the surface of a V-rib.

FIG. 4 is an enlarged sectional view near the surface of a V-rib.

FIG. 5 is a configuration diagram of a V-ribbed belt grinding apparatus.

FIG. 6A is a plan view showing a part of the peripheral surface of the grinding wheel in an enlarged manner, and FIG. 6B is a cross-sectional view taken along line AA of FIG.

FIG. 7 is a configuration diagram of a test device for a performance comparison test.

FIG. 8 is a performance comparison diagram showing a frictional force.

FIG. 9 is a performance comparison diagram showing frictional force during water injection.

FIG. 10 is a sectional view of a combined V-ribbed belt.

[Explanation of symbols]

 2 Tensile body 4 Adhesive rubber layer 7 V rib (bottom rubber part) 8 Aramid short fiber 10 V ribbed belt 11 Side of V rib (surface of bottom rubber part) 15 Protruding part of aramid short fiber 21 Whetstone 24 Super abrasive 25 Grinding wheel 26 Bond part 38 Synthetic fiber 40 Synthetic fiber protrusion

Claims (6)

[Claims] 1. A power transmission belt in which a group of short fibers is mixed into a bottom rubber portion so as to be oriented in a predetermined direction, and a part of the group of short fibers protrudes from a surface of the bottom rubber portion. A transmission belt in which the surface of the rubber part is formed in an uneven shape. 2. The power transmission belt according to claim 1, wherein the unevenness on the surface of the bottom rubber portion is formed in a wind wave shape. 3. The surface of the bottom rubber portion has an unevenness of 0.
The power transmission belt according to claim 1, wherein the power transmission belt has a thickness of 5 μm to 10 μm. 4. A method for manufacturing a power transmission belt in which a surface of a bottom rubber portion is formed in an uneven shape and a short fiber group projects from a surface of the bottom rubber portion, wherein the short fiber group is oriented in a predetermined direction. A method of manufacturing a power transmission belt, comprising a step of grinding a bottom rubber portion mixed as described above with a grindstone having superabrasive grains protruding from 50% to 95% of a grain size. 5. A method of manufacturing a power transmission belt in which a surface of a bottom rubber portion is formed in an uneven shape and a short fiber group projects from a surface of the bottom rubber portion, wherein the short fiber group is oriented in a predetermined direction. A method for manufacturing a power transmission belt, comprising a step of grinding a bottom rubber portion mixed as described above with a grindstone having superabrasive grains having an abrasive grain density of 3.5% to 55%. 6. A method for producing a power transmission belt in which a surface of a bottom rubber portion is formed in an uneven shape and a short fiber group protrudes from the surface of the bottom rubber portion, wherein the short fiber group is oriented in a predetermined direction. Transmission including a step of grinding the mixed bottom rubber portion with a grindstone having super-abrasive grains having a protruding abrasive grain size of 50% to 95% and an abrasive grain density of 3.5% to 55%. Belt manufacturing method.