JP3464939B2 - Power transmission belt and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission belt and a method for manufacturing the same, and more particularly, to a 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 for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-3-21914
As disclosed in Japanese Patent Publication No. 7, a short fiber group is formed in the belt width direction for the purpose of improving lateral pressure resistance and abrasion resistance of a friction transmission portion of a belt and preventing abnormal noise during belt running. There is known a power transmission belt in which a part of the short fiber group is mixed with the bottom rubber portion while maintaining the orientation to the bottom rubber portion so as to protrude from the surface of the bottom rubber portion.

However, even with such a transmission belt, when the area of the protruding portion of the short fiber group occupying the surface of the bottom rubber portion is small, the area where the rubber and the pulley are in direct contact with each other is large, so that the abrasion resistance is high. It does not improve so much.

Therefore, in the power transmission belt disclosed in the above publication, the processing temperature during grinding is raised so that the tips of the short fibers are melted by the heat generated during grinding. As a result, as shown in FIG. 10, the exposed portion 101 of the short fiber 100 is in a flower-like state, and the exposed area of the short fiber 100 is increased.

[0005]

However, when the short fibers are melted, the molecular structure of the fibers is changed, so that the strength thereof is lowered. Therefore, in the above-mentioned power transmission belt, it is difficult to say that the abrasion resistance of the belt is sufficiently improved even though the exposed area of the short fibers is increased.

The present invention has been made in view of the above points, and an object thereof is to improve the abrasion resistance of a belt by increasing the exposed area of the short fibers while maintaining the strength of the short fibers. Especially.

[0007]

In order to achieve the above object, the present invention decided to plastically deform short fibers to form a flat shape.

Specifically, the transmission belt according to the present invention is
A transmission belt in which short fiber groups are mixed in the bottom rubber portion so as to be oriented in a predetermined direction, and a part of the short fiber group is projected from the surface of the bottom rubber portion, wherein the short fiber protrusions are: It is supposed to be formed flat in a plastically deformed state.

According to the above matters, since the protruding portion of the short fiber is not melted, the original strength of the short fiber is maintained. Further, since the protruding portion of the short fiber is plastically deformed by an external force and is formed into a flat shape, the exposed area becomes larger than that in the case where the cross section is circular. Therefore, the abrasion resistance of the belt is improved.

The short fiber projecting portion may be formed in a fan shape that is widened toward the tip.

With the above-mentioned matters, a specific flat structure having a large exposed area can be obtained.

By the way, in the above-mentioned conventional belt, since the exposed short fibers are likely to fall toward the surface of the bottom rubber portion,
It was difficult to form surface irregularities, which are considered to be effective in preventing abnormal noise. Therefore, abnormal noise was likely to occur.

Therefore, it is preferable that the roots of the protruding portions of the short fibers stand upright from the surface of the bottom rubber portion. As a result, microscopic asperities are formed on the surface of the bottom rubber portion, in which the raised protrusions are the protrusions and the embedded portions of the short fibers in the bottom rubber portion are the recesses, and the occurrence of abnormal noise is prevented.

The short fibers are preferably composed of synthetic fibers having a filament diameter of 20 μm or more. Thereby, suitable short fibers can be obtained.

The method of manufacturing a transmission belt according to the present invention has a bottom
The short fiber group is mixed in the rubber part so that it is oriented in the specified direction.
A part of the short fiber group protrudes from the surface of the bottom rubber part,
The protrusions of the short fibers are formed flat in the plastically deformed state.
In the method for manufacturing a power transmission belt , the bottom rubber portion mixed so that the short fiber group is oriented in a predetermined direction is formed by a grindstone having superabrasive grains in which 50% to 95% of the abrasive grain size is projected. This is to include the step of grinding.

According to the above matters, the short fibers are inclined in the grinding direction due to the interference with the superabrasive grains, and the stress generated on the surface of the fibers due to the interference with the superabrasive grains is released, so that the tips of the fibers are curved. While being expanded in the width direction with plastic deformation, a part thereof is removed so as to be torn off, and a flat shape is formed. Further, since the amount of protrusion of the superabrasive grains is large, 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. Therefore, the exposed portions of the short fibers are not heated so much during grinding, and their melting is prevented. Therefore, it is possible to easily obtain the transmission belt in which the projecting portions of the short fibers are plastically deformed.

Another method for manufacturing a power transmission belt according to the present invention is such that the short fiber group is oriented in a predetermined direction on the bottom rubber portion.
When mixed, part of the short fiber group projects from the surface of the bottom rubber part.
And form a flat shape with the protruding portion of the short fiber being plastically deformed.
A method for manufacturing a transmission belt , which comprises a bottom rubber portion in which short fiber groups are mixed so as to be oriented in a predetermined direction,
The method includes a step of grinding with a grindstone having superabrasive grains having an abrasive grain density of 3.5% to 55%.

According to the above matters, since the density of superabrasive grains is small, the chip pocket becomes large, and the grinding chips are easily discharged. Therefore, clogging due to cutting chips is unlikely to occur, and heat generation during grinding is suppressed.
Therefore, it is possible to easily obtain the transmission belt which is plastically deformed while the protruding portions of the short fibers are maintained in the non-melted state.

Another method for manufacturing a power transmission belt according to the present invention is such that short fiber groups are oriented in a predetermined direction in a bottom rubber portion.
When mixed, part of the short fiber group projects from the surface of the bottom rubber part.
And form a flat shape with the protruding portion of the short fiber being plastically deformed.
A method for manufacturing a transmission belt , which comprises a bottom rubber portion in which short fiber groups are mixed so as to be oriented in a predetermined direction,
50% to 95% of the abrasive grain size is projected and the abrasive grain density is 3.5.
It includes a step of grinding with a grindstone having a super-abrasive grain of 50% to 55%.

According to the above matters, since the amount of protrusion of the superabrasive grains is large, 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 of the superabrasive grains is small, the chip pocket becomes large, and the grinding chips are easily discharged. Therefore, clogging due to cutting chips is prevented, and heat generation during grinding is suppressed. Therefore, it is possible to easily obtain the transmission belt which is plastically deformed while the protruding portions of the short fibers are maintained in the non-melted state.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 shows a sectional shape of a transmission belt 10 according to a first embodiment. The power transmission belt 10 is a V-ribbed belt used for drive devices for automobile accessories and other general industrial applications.

In the adhesive rubber layer 4, tensile members 2 extending in the belt length direction are embedded in the belt width direction (left and right direction in FIG. 1) at equal intervals. A canvas layer 5 is provided on the upper surface side of the adhesive rubber layer 4, that is, on the outer surface side of the belt. 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 the "bottom rubber portion" in the present invention. Adhesive rubber layer 4
The V rib 7 is, for example, chloroprene rubber, H-NBR.
It can be formed from rubber, CSM rubber, natural rubber, SBR rubber, butadiene rubber, EPM, EPDM, or the like.

A plurality of synthetic fibers 38, 38, ... Are embedded in the V-rib 7 while maintaining their orientation in a predetermined direction. Specifically, the synthetic fibers 38, 38, ... Are embedded while maintaining their orientation in the belt width direction. As the synthetic fiber 38, a fiber which is easily plastically deformed, for example, nylon, vinylon, polyester having a filament diameter of 20 μm or more can be preferably used.

As shown in FIGS. 2 and 3, a part of the synthetic fiber 38 embedded in the V-rib 7 projects from the side surface 11 of the V-rib 7. The projecting portion 40 of the synthetic fiber 38 is formed in a fan shape that widens toward the tip and is flat . The corners of this fan shape are rounded and formed into a smooth curved surface. Further, the protruding portion 40 of the synthetic fiber 38 is maintained in a non-melted state, and its tip is formed in a corrugated shape.

As shown in FIG. 3, the protrusion 40 of the synthetic fiber 38
The root of the is standing from the side surface 11 of the V rib 7. In other words, the synthetic fiber 38 is substantially upright with respect to the side surface 11 of the V rib 7. As a result, the side surface 11 of the V rib 7 has a convex portion on the tip side from the raised root portion,
Micro recesses and projections are formed with recessed portions embedded in the ribs 7. The length of the protrusion 40 is, for example, 5 μm to 3 μm.
It is 0 μm.

-Method for manufacturing V-ribbed belt- Next, a method of 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 tension member 2, an unvulcanized rubber sheet in which synthetic fibers 38 are mixed, and the like are sequentially laminated, and these are heat-vulcanized. A cylindrical belt molded body is obtained.

Thereafter, as shown in FIG. 4, the belt molded body 19 is attached to the main roll 22 and the tension roll 23 of the drive mechanism 20.
It is wound between and and driven by the drive mechanism 20.
Incidentally, 24A is a guide roll. Then, the grindstone of the belt compact 19 is performed by pressing the grindstone 21 against the belt compact 19 while running while rotating the grindstone 21. As a result, a part of the embedded synthetic fiber 38 has a flat shape and projects from the side surface 11 of the V rib 7. Specifically, the synthetic fiber 38 is inclined in the grinding direction by the interference with the abrasive grains, the tip of the fiber is curved by releasing the stress generated on the surface of the fiber by the interference with the abrasive grains, plastic deformation Along with it, it is removed so as to be partially torn while spreading in the width direction.

[0030] At this time, by adjusting the pressing force or the like of the type and the grinding wheel 21 of the grinding wheel 21, the projection 40 of the synthetic fiber 38 Bian
It is possible to adjust the flatness and the wave shape of the tip.

The grindstone 21 is a disc-shaped grinding wheel 25.
It is preferable to use one having a structure in which 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 also be used. 5A is a view in which a part of the peripheral surface of the grinding wheel 25 is projected from the vertical direction, and FIG. 5B is a cross-sectional view taken along the line AA of FIG. 5A. These FIG. 5 (a)
And as shown in (b), grinding wheel 25 (see FIG. 4)
An adhesive agent (metal bond, nickel bond, etc.) is thinly stretched and applied in layers on the peripheral surface of the bond portion 26.
Are formed.

The diamond abrasive grains 24 are evenly arranged and bonded on the bond portion 26. The grain size of the abrasive grain 24 is #
30 to # 200 are preferable, and set to # 140 in this embodiment. The protrusion amount of the abrasive grains 24 from the bond portion 26 is
It is preferable that the total height of the abrasive grains 24 is 50% to 95%. In this embodiment, the protrusion amount of the abrasive grains 24 is set to 80%. The abrasive grain 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 this embodiment.

In the grinding process, the grinding wheel 25 is set to 5
It is preferable to rotate at a peripheral speed of 00 to 2000 m / min, and the peripheral speed was 1000 m / min in the present embodiment. 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 is 0.004 in this embodiment.

-Effects of this Embodiment- As described above, in the present V-ribbed belt 10, since the protrusion 40 of the synthetic fiber 38 is formed in a flat shape, the appearance of the synthetic fiber 38 with respect to the side surface 11 of the V-rib 7 is apparent. The upper area is larger than that in the case where the cross-sectional shape of the protrusion is circular. Further, since the tip of the protrusion 40 of the synthetic fiber 38 is formed in a corrugated shape, the surface area of the synthetic fiber 38 is further increased as compared with the case where the tip is flat. Therefore, this V-ribbed belt 10
Has high wear resistance.

Since the protruding portion 40 of the synthetic fiber 38 is plastically deformed and is maintained in a non-melted state, the original strength of the synthetic fiber is maintained in the protruding portion 40. Therefore, synthetic fiber 38
The protrusion 40 of the belt is hard to wear, and the wear resistance of the belt is further improved.

Since the projecting portion 40 of the synthetic fiber 38 is formed in a rounded fan shape, even when the surface pressure on the side surface 11 of the V-rib 7 is large or when the surface pressure is uneven. Even if there is, a stable sliding resistance can be obtained.

Since the root of the protruding portion 40 of the synthetic fiber 38 stands up against the side surface 11 of the V-rib 7, it is possible that water, oil or the like is mixed in the sliding portion between the belt and the pulley. However, they are easily discharged through the roots of the protrusions 40. Therefore, the sliding resistance is stable even when water or the like is mixed in the sliding portion.

Since the V-rib 7 is ground using the super-abrasive grains in which 50% to 95% of the abrasive grain size protrudes from the bond portion 26, the bond portion 26 and the V-rib 7 are ground. Contact is unlikely. Therefore, less heat is generated due to friction. Further, since the abrasive grains 24 are formed of diamond having a relatively high thermal conductivity, the heat generated during grinding easily escapes to the grinding wheel 25 side. Therefore, the temperature of the protruding portion 40 of the synthetic fiber 38 does not rise to the extent of melting (melting point), and the non-melting state of the synthetic fiber 38 is maintained.

The abrasive grain density of superabrasive grains is 3.5% to 5%.
Since it is relatively coarse at 5%, the gap between the abrasive grains, that is, the chip pocket becomes large. Therefore, clogging due to chips is less likely to occur during grinding. Therefore, heat generation due to clogging is suppressed, and the non-melted state of the protrusion 40 of the synthetic fiber 38 is easily maintained.

Performance Comparison Example Next, a performance comparison test comparing the V-ribbed belt 10 according to this embodiment with a conventional V-ribbed belt will be described. The synthetic fibers 38 of the V-ribbed belt 10 are 2
0-25 phr nylon was used. As the conventional V-ribbed belt, the one in which the exposed portion of the short fiber is in a molten state like a flower is used.

The test was conducted as follows. That is, as shown in FIG. 6, the sample belt 32 is attached to the guide roller 33.
The weight of the weight W is hung down through the load cell 31 and the load cell value of the load cell 31 is detected to detect the tension T1 on the tension side and the tension T2 on the slack side of the belt, and the ratio (tension ratio) T1 / T2 with the passage of time. This was done by calculating the change. It should be noted that the tension ratio T1 / T2 is equal to the friction coefficient μ = (1
/ Π) ln (T1 / T2). The rotation speed of the guide roller 33 is 43 rpm, and the weight W is 1.7.
It was set to 5 kg.

As a result, as shown in FIG. 7, in the V-ribbed belt 10, the tension ratio T1 / T2 is almost varied between the initial state (when new) and the state after continuous running for 24 hours (when running is deteriorated). However, it was clarified that the fluctuation amount was significantly reduced compared to the conventional method. Further, as a result of performing the same measurement under a high temperature condition of 100 ° C. and a high load condition, as compared with the case of a conventional belt, the tension ratio T1 /
It was found that the tension ratio T1 / T2 did not increase so much with the V-ribbed belt 10 while the T2 was considerably increased, and that the change over time was small. This is because in the conventional belt, the short fibers are rapidly worn from the molten portion and the surface area thereof is significantly reduced, whereas in the V-ribbed belt 10, the protrusion 40 of the synthetic fiber 38 is in a non-melted state. It is considered that the main cause is that the strength of the synthetic fiber 38 is maintained even under high temperature and high load conditions, and the surface area thereof is not reduced so much.

FIG. 8 shows changes with time in the refractive index of rubber under a high temperature condition of 100 ° C. It can be seen from FIG. 8 that the V-ribbed belt 10 has a smaller change in refractive index with time than the conventional belt.

-Modification- The application of the present invention is not limited to the V-ribbed belt 10 described above, and other types of V-ribbed belts may be used. For example, it may be a combined V-ribbed belt 10A as shown in FIG. Further, another transmission belt such as a V belt may be used.

[0045]

As described above, according to the present invention, since the projecting portion of the short fiber is formed flat while being plastically deformed, the original strength of the short fiber can be maintained and the exposed area of the short fiber can be maintained. Since it is possible to secure a large value, it is possible to improve the abrasion resistance of the belt.

By forming the projecting portion of the short fiber in a fan shape which is divergent toward the tip, the projecting portion of the short fiber can be formed in a flat shape having a large exposed area.

By forming the protruding portions of the short fibers so that the roots thereof stand upright from the surface of the bottom rubber portion, it is possible to form micro unevenness on the surface of the bottom rubber portion, which causes abnormal noise. Can be prevented.

By constructing the short fibers with synthetic fibers having a filament diameter of 20 μm or more, it is possible to obtain a suitable specific configuration that exhibits the above effects.

The bottom rubber portion mixed with short fibers is ground by a grindstone having superabrasive grains in which 50% to 95% of the abrasive grain size is projected, so that the bond portion and the bottom rubber portion of the belt are brought into contact with each other. It is possible to prevent the generation of frictional heat. Therefore, it becomes easy to plastically deform the short fibers and allow the short fibers to protrude from the surface of the bottom rubber portion while maintaining the non-melted state.

By grinding the bottom rubber portion mixed with the short fibers with a grindstone having superabrasive grains having an abrasive grain density of 3.5% to 55%, clogging by cutting chips is prevented, and at the time of grinding. It is possible to suppress heat generation. Therefore, it becomes easy to plastically deform the short fibers and allow the short fibers to protrude from the surface of the bottom rubber portion while maintaining the non-melted state.

In the bottom rubber portion mixed with short fibers, 50% to 95% of the abrasive grain size is projected and the abrasive grain density is 3.5% to 55%.
By grinding with a whetstone with% superabrasives,
It is possible to suppress frictional heat between the bond portion and the bottom rubber portion and heat generation due to clogging of cutting chips. Therefore, it becomes easy to plastically deform the short fibers and allow the short fibers to protrude from the surface of the bottom rubber portion while maintaining the non-melted state.

[Brief description of drawings]

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

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

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

FIG. 4 is a configuration diagram of a V-ribbed belt grinding device.

5A is an enlarged plan view showing a part of the peripheral surface of the grinding wheel, and FIG. 5B is a sectional view taken along line AA of FIG.

FIG. 6 is a configuration diagram of a test device for a performance comparison test.

FIG. 7 is a performance comparison diagram showing a change in tension ratio.

FIG. 8 is a performance comparison diagram showing the refractive index of rubber.

FIG. 9 is a cross-sectional view of a combined V-ribbed belt.

FIG. 10 is a diagram showing short fibers of a conventional belt.

[Explanation of symbols]

2 Tensile body 4 Adhesive rubber layer 7 V rib (bottom rubber part) 10 V ribbed belt 11 V rib side surface (bottom rubber surface) 21 whetstone 24 abrasive grains 25 grinding wheel 26 Bond Department 38 Synthetic fiber 40 Projection

Continuation of the front page (56) References JP-A-3-219147 (JP, A) JP-A-7-269658 (JP, A) JP-A-9-267248 (JP, A) JP-A-10-329029 (JP , A) JP 62-113940 (JP, A) JP 7-280040 (JP, A) JP 3-265741 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) F16G 1/00-9/04 B29D 29/00-29/10

Claims (7)

(57) [Claims] 1. A transmission belt in which a short fiber group is mixed in a bottom rubber portion so as to be oriented in a predetermined direction, and a part of the short fiber group projects from the surface of the bottom rubber portion. The projecting part of is a transmission belt that is formed flat in a plastically deformed state. 2. The transmission belt according to claim 1, wherein the projecting portion of the short fiber is formed in a fan shape that is widened toward the tip. 3. The transmission belt according to claim 1, wherein the root of the protruding portion of the short fiber is erected from the surface of the bottom rubber portion. 4. The transmission belt according to claim 1, wherein the short fiber is made of synthetic fiber having a filament diameter of 20 μm or more. 5. A short fiber group is oriented in a predetermined direction on the bottom rubber portion.
And the short fiber group from the surface of the bottom rubber part.
Part of the short fiber is protruding and the protruding part of the short fiber is plastically deformed
A method for manufacturing a flat transmission belt , wherein a bottom rubber portion mixed so that the short fiber group is oriented in a predetermined direction is superabrasive in which 50% to 95% of the abrasive grain size is projected. A method for manufacturing a power transmission belt, which includes a step of grinding with a grindstone having grains. 6. A short fiber group is oriented in a predetermined direction on the bottom rubber portion.
And the short fiber group from the surface of the bottom rubber part.
Part of the short fiber is protruding and the protruding part of the short fiber is plastically deformed
A method for manufacturing a transmission belt that is formed into a flat shape, wherein a bottom rubber portion mixed so that short fiber groups are oriented in a predetermined direction is superabrasive with an abrasive grain density of 3.5% to 55%. A method for manufacturing a power transmission belt, which includes a step of grinding with a grindstone having grains. 7. The short fiber group is oriented in a predetermined direction on the bottom rubber portion.
And the short fiber group from the surface of the bottom rubber part.
Part of the short fiber is protruding and the protruding part of the short fiber is plastically deformed
In a method for manufacturing a transmission belt that is formed into a flat shape, the bottom rubber portion mixed so that the short fiber group is oriented in a predetermined direction has 50% to 95% of the abrasive grain protruding and the abrasive grain A method for manufacturing a power transmission belt, comprising a step of grinding with a grindstone having a superabrasive grain having a density of 3.5% to 55%.