JP7239788B1 - Toothed belt and transmission system - Google Patents

Abstract

A toothed belt in which belt teeth are provided at a constant pitch in the longitudinal direction of the belt, wherein the belt teeth are provided so as to mesh with a pulley having pulley grooves provided at a constant pitch on the periphery thereof, The length of the contour line in the contour shape viewed from the side is longer than the length of the contour line in the contour shape of the pulley groove viewed from the side, and the height of the point on the contour line of the belt tooth is the contour of the belt tooth. A toothed belt, wherein the height of the intersection of a line and the center line of said belt teeth is maximum.

Description

The present invention relates to toothed belts and transmission systems.
This application claims priority based on Japanese application No. 2021-143206 filed on September 2, 2021, and incorporates all the descriptions described in the Japanese application.

A transmission system comprising a toothed belt and pulleys is used for power transmission in general industrial applications and electric power steering.
A problem with such a transmission system is that noise is generated when the toothed belt and the pulley are meshed.

In response to this problem, for example, Patent Literature 1 proposes a transmission system that reduces noise caused by meshing vibration that occurs during operation of a transmission system composed of a toothed belt and pulleys.
The transmission system of Patent Document 1 includes a toothed belt having teeth that are symmetrical with respect to the center line in a cross section along the longitudinal direction, a drive pulley having grooves that engage with the teeth on the outer peripheral surface, and and a driven pulley, wherein the groove faces at a position separated by a predetermined distance from a reference line set in the longitudinal direction of the toothed belt when the toothed belt is engaged with the pulley. The distance between the two side surfaces is smaller than the distance between the two side surfaces of the tooth portion separated by the predetermined distance, and the groove depth of the groove portion is larger than the tooth height of the tooth portion. .

JP-A-2000-193068

There is a constant demand for noise reduction in transmission systems composed of toothed belts and pulleys.

The inventors of the present invention conducted intensive studies to reduce the noise during operation of the transmission system, and completed a transmission system that achieves noise reduction based on an unprecedented new idea.

(1) The toothed belt of the present invention is a toothed belt in which belt teeth are provided at a constant pitch in the longitudinal direction of the belt,
The belt tooth is provided so as to mesh with a pulley having pulley grooves provided at a constant pitch on the periphery,
The length of the contour line in the contour shape of the belt tooth viewed from the side is longer than the length of the contour line of the contour shape viewed from the side of the pulley groove,
The maximum height of a point on the contour line of the belt tooth is the height of the intersection point between the contour line of the belt tooth and the center line of the belt tooth.

In the toothed belt, the length of the contour line in the contour shape of the belt teeth viewed from the side satisfies the above-described configuration in relation to the meshing pulley. Therefore, the toothed belt is less likely to generate noise when driven.

In the toothed belt, the height of a point on the contour line of the contour shape of the belt teeth viewed from the side (hereinafter also simply referred to as the side view shape) is the height between the contour line of the belt teeth and the center line of the belt teeth. The height of the intersection point is the maximum. Belt teeth having such a side view shape include H-shaped arcuate teeth, S-shaped arcuate teeth, and the like.
The height of a point on the contour line in the side view shape of the belt tooth refers to the shortest distance between a line segment connecting two roots of the belt tooth and the point on the contour line.

From the viewpoint of further reducing noise, the toothed belt preferably satisfies at least one of the following requirements (2) to (4).

(2) In the toothed belt, the contour shape of the belt teeth viewed from the side is obtained by superimposing the contour shape of the belt teeth viewed from the side and the contour shape of the pulley grooves viewed from the side at a position satisfying the following condition. The shape is such that there are three or five points of intersection between the outline of the shape and the outline of the pulley groove viewed from the side.
Conditions: A position where the center line of the belt tooth and the center line of the pulley groove coincide, and the intersection point of the contour line of the belt tooth and the center line coincides with the intersection point of the contour line and the center line of the pulley groove.

(3) In the toothed belt, the belt teeth have a distance from the center line of the belt teeth to the pressure surface in the contour shape viewed from the side, and The belt teeth are configured such that two pressure surfaces and tooth tips contact the pulley grooves when the belt teeth are engaged with the pulley grooves.

(4) In the toothed belt, the ratio of the tooth height of the belt teeth to the depth of the pulley grooves is 100% or more and 110% or less.
It is more preferable to satisfy two of these requirements (2) to (4), and more preferably to satisfy all three.

(5) The transmission system of the present invention comprises a toothed belt having belt teeth provided at a constant pitch in the longitudinal direction of the belt, and a pulley having pulley grooves provided at the periphery thereof at a constant pitch so as to mesh with the belt teeth. A transmission system comprising
The length of the contour line in the contour shape of the belt tooth viewed from the side is longer than the length of the contour line of the contour shape viewed from the side of the pulley groove,
The maximum height of a point on the contour line of the belt tooth is the height of the intersection point between the contour line of the belt tooth and the center line of the belt tooth.

In the above transmission system, the length of the contour of the belt teeth provided on the toothed belt when viewed from the side and the length of the contour of the contour of the pulley grooves provided on the pulley when viewed from the side are as described above. happy with the relationship. Therefore, the transmission system is less likely to generate noise when driven.
From the viewpoint of further reducing noise during driving, the transmission system preferably satisfies at least one of the following requirements (6) to (8).

(6) In the above transmission system, the contour shape of the belt teeth viewed from the side is obtained by superimposing the contour shape of the belt teeth viewed from the side on the contour shape of the pulley grooves viewed from the side at a position that satisfies the following condition. and the outline of the pulley groove viewed from the side have three or five points of intersection.
Conditions: A position where the center line of the belt tooth and the center line of the pulley groove coincide, and the intersection point of the contour line of the belt tooth and the center line coincides with the intersection point of the contour line and the center line of the pulley groove.

(7) In the transmission system, the belt tooth has a distance from the center line of the belt tooth to the pressure surface that is equal to or greater than the distance from the center line of the pulley groove to the pressure surface, and The belt teeth are configured such that when meshing with the pulley grooves, two pressure surfaces and tooth tips are in contact with the pulley grooves.

(8) In the transmission system, the ratio of the tooth height of the belt to the depth of the pulley groove is 100% or more and 110% or less.
It is more preferable to satisfy two of these requirements (6) to (8), and it is even more preferable to satisfy all three of them.

The toothed belt and the transmission system with the toothed belt can reduce noise during operation.

1 is a side view schematically showing a transmission system according to a first embodiment; FIG. FIG. 2 is a perspective view showing part of a toothed belt included in the transmission system of FIG. 1; 3 is a front view of arrow X in FIG. 2; FIG. 3 is a front view of arrow Y in FIG. 2; FIG. FIG. 3 is an end view taken along line AA of FIG. 2; FIG. 4 is a diagram showing the relationship between the side view shape of belt teeth of a toothed belt and the side view shape of pulley grooves of a pulley in the transmission system according to the first embodiment (Example 1). FIG. 4 is a partial cross-sectional view of a belt mold used for manufacturing toothed belts; It is a figure explaining the manufacturing process of a toothed belt. It is a figure explaining the manufacturing process of a toothed belt. It is a figure explaining the manufacturing process of a toothed belt. FIG. 10 is a diagram showing the relationship between the side view shape of the belt teeth of the toothed belt and the side view shape of the pulley grooves of the pulley in the transmission system according to the second embodiment; FIG. 10 is a diagram showing the relationship between the side view shape of belt teeth of a toothed belt and the side view shape of pulley grooves of a pulley in the transmission system according to the third embodiment; FIG. 10 is a diagram showing the relationship between the side view shape of belt teeth of a toothed belt and the side view shape of pulley grooves of a pulley in the transmission system according to the fourth embodiment; 8 is a diagram showing the relationship between the side view shape of the belt teeth of the toothed belt and the side view shape of the pulley grooves of the pulley in the transmission system according to Comparative Example 1. FIG. It is a figure which shows the dimension of the pulley groove which a pulley has. 16(a) and 16(b) are diagrams schematically showing a method of evaluating the noise of a transmission system. 4 is a diagram showing the results of noise evaluation of Examples 1 to 4 and Comparative Example 1. FIG.

Embodiments of the present invention will be described below. The invention is not limited to these embodiments.
(First embodiment)
FIG. 1 is a side view schematically showing a transmission system 10 according to this embodiment.
The transmission system 10 is used, for example, in a power steering system for automobiles.
As shown in FIG. 1, the transmission system 10 includes a driving pulley 12 in which a plurality of pulley grooves 13 are formed at a predetermined pitch, a driven pulley 14 in which a plurality of pulley grooves 15 are formed at a predetermined pitch, and a pulley groove. 13 and a plurality of belt teeth 20A (see FIG. 2) that mesh with the pulley grooves 15, and is provided with a toothed belt 18 stretched over the drive pulley 12 and the driven pulley 14. As shown in FIG.

Both the drive pulley 12 and the driven pulley 14 are provided with pulley grooves 13 and 15 at predetermined pitches on the peripheral edges thereof so as to mesh with the belt teeth 20A of the toothed belt 18 . Here, the side view shape of the pulley groove 13 of the driving pulley 12 and the side view shape of the pulley groove 15 of the driven pulley 14 are the same.

FIG. 2 is a perspective view showing a portion of the toothed belt 18 that constitutes the transmission system 10. As shown in FIG.
3 is a front view of arrow X in FIG. 2. FIG.
4 is a front view of arrow Y in FIG. 2. FIG.
FIG. 5 is an end view taken along line AA of FIG. 2. FIG.
Although only a portion of the toothed belt 18 is shown in FIG. 2, the toothed belt 18 is an endless meshing transmission belt.

The toothed belt 18 is provided with a plurality of belt teeth 20A on the inner peripheral side thereof at predetermined pitches in the circumferential direction. The belt teeth 20A are so-called helical teeth that are formed of ridges extending in a direction that is inclined with respect to the belt width direction.
The tooth profile of the belt teeth 20A is an H tooth profile, which is one of arc tooth profiles. In the present embodiment, the contour lines of the belt teeth in side view (broken lines in FIG. 6) constitute the contour lines of the belt teeth.

The toothed belt 18 is relatively small, for example, with a belt circumference (belt length on the belt pitch line BL) of 400 mm or less and a pitch P of the belt teeth 20A of 0.50 mm or more and 5.0 mm or less. .

The belt circumferential length of the toothed belt 18 is preferably 100 mm or more and 400 mm or less, more preferably 150 mm or more and 380 mm or less.
The belt width of the toothed belt 18 is, for example, 4 mm or more and 30 mm or less, and the belt maximum thickness is, for example, 1.1 mm or more and 3.0 mm or less.
The pitch P of the belt teeth 20A is preferably 0.50 mm or more and 3.0 mm or less.
The width of the belt tooth 20A is defined by the dimension between the ends of a pair of adjacent tooth bottom portions 20B sandwiching the belt tooth 20A in the belt circumferential direction, and is, for example, 0.8 mm or more and 3.3 mm or less.
The inclination angle θ (see FIG. 4) of the belt teeth 20A with respect to the belt width direction is, for example, greater than 0° and less than or equal to 15° when the belt teeth 20A are helical teeth.

The toothed belt 18, as shown in FIGS.

The belt main body 21 has a flat belt-shaped back rubber portion 111 and a plurality of tooth rubber portions 112 arranged on the inner peripheral side of the back rubber portion 111 .
The thickness of the back rubber portion 111 is, for example, 0.30 mm or more and 1.6 mm or less, preferably 0.50 mm or more and 1.40 mm or less.
Each of the plurality of tooth rubber portions 112 is provided integrally with the back rubber portion 111 to constitute the belt tooth 20A. The tooth height of the belt teeth 20A (the height of the belt teeth 20A) is, for example, 0.50 mm or more and 2.0 mm or less. Here, the tooth height of the belt tooth 20A means the distance in the thickness direction of the belt from the adjacent tooth bottom 20B to the apex P12 of the tooth tip of the belt tooth 20A (see H in FIG. 5).

The belt body 21 is made of a rubber composition obtained by heating and pressurizing an uncrosslinked rubber composition in which various rubber compounding agents are blended into a rubber component to crosslink the rubber component with a crosslinking agent. The details of the constituent material of the belt body 21 will be described later.

The core wire 22 is arranged and embedded in a portion 111a on the inner peripheral side of the back rubber portion 111 of the belt body 21 so as to form a spiral having a pitch in the belt width direction.
The outer diameter φT of the cord 22 in the belt thickness direction may be the same as the outer diameter φW in the belt width direction, or may be smaller than the outer diameter φW in the belt width direction.
The outer diameters φT and φW of the cord 22 in the belt thickness direction and the belt width direction are, for example, 0.15 mm or more and 0.80 mm or less, preferably 0.25 mm or more and 0.50 mm or less.

The tooth portion reinforcing cloth 23 is attached so as to cover the surface of the belt body 21 on the inner peripheral side where the plurality of tooth rubber portions 112 are provided. Accordingly, the tooth rubber portion 112 of each belt tooth 20</b>A is covered with the tooth portion reinforcing cloth 23 .
In the tooth bottom portion 20B, the core wire 22 embedded in the inner peripheral portion 111a of the back rubber portion 111 of the belt body 21 is arranged immediately inside the tooth portion reinforcing cloth 23 (on the outer peripheral side of the belt). The thickness of the tooth reinforcing cloth 23 is, for example, 0.05 mm or more and 0.3 mm or less.

Each belt tooth 20</b>A of the toothed belt 18 is provided so as to mesh with the pulley groove 13 provided on the periphery of the drive pulley 12 and the pulley groove 15 provided on the periphery of the driven pulley 14 .
FIG. 6 is a diagram showing the relationship between the side view shape of one belt tooth 20A of the toothed belt 18 and the side view shape of one pulley groove 13A of the driving pulley 12 in the transmission system 10 of the present embodiment. is. In FIG. 6, the outline of the belt tooth 20A is indicated by a broken line, and the outline of the pulley groove 13A is indicated by a solid line.
The belt tooth 20A is configured such that the length of the contour line L1 in the side view of the belt tooth 20A is longer than the length of the contour line L2 in the side view of the pulley grooves 13 and 15. there is Therefore, it is suitable for suppressing noise generated when the belt teeth and the pulley grooves mesh.

The length L1 of the contour line of the belt tooth 20A refers to the length of the contour line from one tooth base P11 of the belt tooth 20A to the other tooth base P13 through the tooth tip apex P12.
Here, the roots P11 and P13 of the belt tooth 20A are boundaries between the belt tooth 20A and the adjacent tooth bottom 20B, respectively, and the points of contact between the arc p2 of the root circle of the belt tooth 20A and the straight line p1 of the tooth bottom 20B. is.

In addition, the length of the contour line (the length of the groove bottom outline) L2 of the pulley groove 13A is the contour from one groove base Q11 of the pulley groove 13A to the other groove base Q13 through the groove bottom apex Q12. refers to the length of a line.
Here, each of groove roots Q11 and Q13 of pulley groove 13A is a boundary between pulley groove 13A and adjacent pulley tooth 13B. is the point of contact with the arc q2 of .

In the transmission system 10, the ratio (L1/L2) of the profile length L1 of the belt tooth 20A to the profile length L2 of the pulley groove 13A is about 1.06.
In an embodiment of the present invention, the above ratio (L1/L2) should be greater than 1.0, for example, 1.03 or more and 1.10 or less.

The transmission system 10 has a side view contour shape of one belt tooth 20A of the toothed belt 18 and a side view contour shape of one pulley groove 13A of the driving pulley 12 (hereinafter also simply referred to as the pulley 12). are overlapped at positions satisfying a predetermined requirement, the number of intersections (including points of contact) between the contour of the belt tooth 20A and the contour of the pulley groove 13A is five.
Here, the overlapping position of the belt teeth 20A and the pulley grooves 13A is the point where the center line CL of the belt teeth 20A and the center line CL of the pulley grooves 13A coincide and the intersection of the outline of the belt teeth 20A and the center line. (Top end of belt tooth 20) P12 coincides with intersection point Q12 between the outline of pulley groove 13A (outline of tooth bottom of pulley) and the center line.
In the example shown in FIG. 6, each of X11 to X15 is the intersection of the contour of the belt tooth 20A and the contour of the pulley groove 13A.

The number of intersections between the contour line of the belt tooth 20A and the contour line of the pulley groove 13A is determined by the section from one tooth root P11 of the belt tooth 20A to the other tooth root P13 through the tooth tip apex P12 and the pulley groove It is the number of intersections with sections extending from one groove base Q11 of 13A to the other groove base Q13 through the groove bottom apex Q12.
When the outline of the belt teeth 20A and the outline of the pulley grooves 13A are superimposed under the above conditions, if the number of intersections is five, the combination of the toothed belt 18 and the pulley 12 is the belt teeth 20. This combination makes it difficult for noise to occur when meshing with the pulley groove 13 .

Furthermore, in the contour shape of the belt teeth 20A viewed from the side, the distance from the center line CL to the pressure surface 26 is greater than the distance from the center line CL of the pulley groove 13A to the pressure surface 16, and the belt teeth 20A are located on the pulley. The two pressure surfaces 26, 26 and the tip P12 are configured to contact the pulley groove 13A when meshing with the groove 13A.
Having such a configuration is particularly suitable for suppressing noise when the belt teeth 20 and the pulley grooves 13 mesh. When the belt teeth 20 and the pulley grooves 13 are engaged with each other, the tips and roots of the belt teeth 20 first come into contact with the pulley 12, and the contact noise at that time may increase the noise. On the other hand, by adopting the above configuration, the two pressure surfaces 26, 26 of the belt teeth 20 first come into contact with the pulley grooves 13, and when the tooth tips P12 of the belt teeth 20 and the pulley 12 come into contact with each other. The speed can be attenuated, and the contact pressure between the roots P11 and P13 of the belt teeth 20 and the pulley 12 can be relaxed. As a result, the transmission system 10 is much less noisy.
Further, when the belt teeth 20 and the pulley grooves 13 mesh with each other under the condition that the two pressure surfaces 26, 26 and the tooth tips P12 of the belt teeth 20 are in contact with the pulley 12, the belt teeth 20 are not desired. It is possible to suppress the deformation of the belt teeth 20 and the deviation of the belt teeth 20 at the time of meshing.

In the embodiment of the present invention, the pressure surface refers to a surface that transmits and receives power when the belt teeth and the pulley grooves are meshed with each other.
Further, the distance between the pressure surface of the belt tooth and the center line CL is a point (P14, P15) and the shortest distance (D1 in FIG. 6) from the center line CL.
Further, the distance between the pressure surface of the pulley groove and the center line CL is a point (Q14 , Q15) and the center line CL (D2 in FIG. 6).
In an embodiment of the present invention, it is preferable that the distance from the center line of the belt tooth to the pressure surface is equal to or greater than the distance from the center line of the pulley groove to the pressure surface in the contour shape viewed from the side.

In the transmission system 10, the tooth height of the belt teeth 20A and the depth of the pulley grooves 13A match. Therefore, the belt teeth 20A and the pulley grooves 13A of the transmission system 10 have a shape suitable for the apexes P12 of the tooth tips of the belt teeth 20A to come into contact with the pulley grooves 13 when they are meshed.
Here, the depth of the pulley groove 13A means the difference between the addendum circle radius of the pulley 12 and the dedendum circle radius of the pulley 12 .

In the transmission system 10, the teeth of the toothed belt are H-tooth arc teeth, and the tooth grooves of the pulley are S-tooth arc teeth.
By adopting such a combination of the toothed belt and the pulley, the number of intersections of the contour of the belt teeth 20A and the contour of the pulley groove 13 can be easily reduced to five, which is particularly suitable for noise reduction.

In the description of the present embodiment, with reference to FIG. 6, the relationship between the belt teeth 20A and the pulley grooves 13A of the driving pulley 12 was described. The side view shape of the pulley groove 13 of the driven pulley 14 is the same as the side view shape of the pulley groove 15 of the driven pulley 14 . Therefore, the relationship between the side view shape of the belt tooth 20A and the side view shape of one pulley groove 15 of the driven pulley 14 is the same as the relationship between the belt tooth 20A and the pulley groove 13A of the driving pulley 12.

(Other embodiments)
In the embodiment of the present invention, when the contour shape of the belt tooth 20A viewed from the side and the contour shape of the pulley groove 13A viewed from the side are overlapped at a position satisfying the above-described predetermined requirements, the contour line of the belt tooth 20A and the contour line of the pulley groove 13A is not limited to five.
The number of intersection points may be, for example, three (see FIGS. 12 and 13), or may be another number.

In an embodiment of the present invention, the ratio of the tooth height of the belt teeth to the depth of the pulley grooves is preferably 100% or more and 110% or less.
If the tooth height of the belt teeth is smaller than the depth of the pulley grooves, the tooth tips of the belt teeth do not come into contact with the pulley grooves during meshing, resulting in a poor noise suppression effect. On the other hand, if the above ratio exceeds 110%, only the tooth tips of the belt teeth come into contact with the pulley grooves during meshing, and noise may not be suppressed.
More preferably, the ratio of the tooth height of the belt teeth to the depth of the pulley grooves is 100% or more and 107% or less.

In the embodiment of the present invention, the belt teeth of the toothed belt are not limited to helical teeth, and may be so-called straight teeth that are configured with ridges formed so as to extend in the belt width direction.
When the belt teeth of the toothed belt are straight teeth, a pulley having straight teeth on the outer periphery is also selected as the pulley.

The constituent materials of the toothed belt will be described below.
The belt main body is formed of a rubber composition obtained by heating and pressurizing an uncrosslinked rubber composition in which various rubber compounding agents are blended into a rubber component to crosslink the rubber component with a crosslinking agent.
Examples of the rubber component of the rubber composition forming the belt body include hydrogenated nitrile rubber (H-NBR), chlorosulfonated polyethylene rubber, chloroprene rubber, ethylene-α- Examples include olefin elastomers.

Examples of rubber compounding agents include vulcanization accelerator aids, anti-aging agents, reinforcing materials, plasticizers, co-crosslinking agents, and cross-linking agents.
Examples of the vulcanization accelerator aid include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids and derivatives thereof. It is preferable to use one or more of these as the vulcanization accelerator aid, and it is more preferable to use zinc oxide.
The content of the vulcanization accelerator aid is, for example, 3 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component.

Examples of the anti-aging agent include benzimidazole-based, aromatic secondary amine-based, and amine-ketone-based anti-aging agents. It is preferable to use one or more of these anti-aging agents, and it is more preferable to use a combination of benzimidazole-based and aromatic secondary amine-based anti-aging agents.
Content of the said antioxidant is 1.5 to 3.5 mass parts with respect to 100 mass parts of rubber components, for example.

Examples of the reinforcing material include carbon black and silica.
Examples of the carbon black include channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF and N-234; thermal black such as FT and MT. ; and acetylene black. These may be used alone or in combination of two or more.
At least HAF is preferably used as the carbon black.
Carbon black and silica are preferably used in combination as the reinforcing material.

When carbon black is used as the reinforcing material, its content is, for example, 10 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber component.
When silica is used as the reinforcing material, its content is, for example, 10 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber component.

Examples of the plasticizer include polyether esters, dialkyl sebacates such as dioctyl sebacate (DOS), dialkyl phthalates such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), and dialkyl adipates such as dioctyl adipate (DOA). is mentioned. These may be used alone or in combination of two or more.
As the plasticizer, it is preferable to use at least polyetherester.
The content of the plasticizer is, for example, 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component.

Examples of the co-crosslinking agent include trimethylolpropane trimethacrylate, m-phenylenedimaleimide, zinc dimethacrylate, and triallyl isocyanurate. These may be used alone or in combination of two or more.
As the co-crosslinking agent, trimethylolpropane trimethacrylate and m-phenylenedimaleimide are preferably used in combination.
The content of the co-crosslinking agent is, for example, 3 parts by mass or more and 8 parts by mass or less with respect to 100 parts by mass of the rubber component.

Examples of the cross-linking agent include sulfur and organic peroxides. Either one of them may be used alone, or both may be used in combination.
When sulfur and an organic peroxide are used together as the cross-linking agent, the total amount of the cross-linking agent is, for example, 0.1 parts by mass or more and 0.7 parts by mass of sulfur with respect to 100 parts by mass of the rubber component. or less, and the organic peroxide is 1 part by mass or more and 5 parts by mass or less.

The core wire is made of twisted yarn made of glass fiber, aramid fiber, carbon fiber, metal fiber, or the like.
The core wire may be provided such that the S-strand and the Z-strand form a double helix, or may consist of a single S-strand or Z-strand.
The core wire is subjected to one or both of an RFL treatment in which it is immersed in an RFL aqueous solution and then heated, and a rubber paste treatment in which it is immersed in a rubber paste and then dried as an adhesive treatment for increasing the adhesive strength with the belt body. may have been
Prior to the bonding treatment, the core wire may be subjected to a surface treatment of being immersed in an epoxy solution or an isocyanate solution and then heated.

The tooth reinforcing fabric is composed of, for example, nylon fiber (polyamide fiber), polyester fiber, aramid fiber, polyparaphenylenebenzobisoxazole (PBO) fiber, woven fabric, knitted fabric, non-woven fabric, etc. formed of yarn such as cotton. It is Among these, woven fabrics of nylon fibers are preferred.
It is preferable that the tooth reinforcing fabric has stretchability, for example, a woven fabric in which the weft threads are subjected to woolly processing or the like.
The tooth reinforcing cloth is subjected to an adhesive treatment for increasing the adhesive strength with the belt body, an RFL treatment in which it is immersed in an RFL aqueous solution and then heated, a soaking treatment in which it is immersed in a low-viscosity rubber paste and then dried, and a high One or two or more of coating treatments may be applied to the surface of the belt main body side, in which a viscous rubber paste is applied and dried.
Prior to the bonding treatment, the tooth reinforcing cloth may be subjected to a base treatment in which the cloth is immersed in an epoxy solution or an isocyanate solution and then heated.

Next, a method for manufacturing the toothed belt 18 will be described with reference to FIGS. 7 to 10. FIG.
The method of manufacturing the toothed belt 18 has a material preparation process, a molding process, a cross-linking process, and a finishing process.

<Material preparation process>
An uncrosslinked rubber composition having relatively high rubber hardness is obtained by masticating a predetermined rubber component, adding various rubber compounding agents thereto, and kneading the mixture. Then, an uncrosslinked rubber composition sheet 21' is produced by subjecting the obtained uncrosslinked rubber composition to calendar molding or the like.

Adhesion treatment is applied to each of the core wire 22 and the tooth reinforcing cloth 23 . Further, the tooth portion reinforcing cloth 23 is formed into a tubular shape.

<Molding process>
FIG. 7 is a partial cross-sectional view showing part of the belt molding die 30. As shown in FIG.
The belt forming die 30 has a cylindrical shape, and has a plurality of tooth forming grooves 31 each formed to extend in a direction inclined with respect to the axial direction. have

As shown in FIG. 8, the outer peripheral surface of the belt forming die 30 is covered with a tubular tooth reinforcing cloth 23, and the core wire 22 is spirally wound thereon.
Then, the uncrosslinked rubber composition sheet 21′ is wound thereon, and an uncrosslinked slab S′ composed of the tooth reinforcing cloth 23, the cord 22 and the uncrosslinked rubber composition sheet 21′ is formed on the belt mold 30. do. The uncrosslinked rubber composition sheet 21' is preferably used so that the grain direction corresponds to the longitudinal direction of the belt.

<Crosslinking step>
As shown in FIG. 9, an uncrosslinked slab S′ on a belt mold 30 is covered with a rubber sleeve 32, placed in a vulcanization can and sealed, and high-temperature and high-pressure steam is introduced into the vulcanization can. It is filled and held for a predetermined molding time. By pressing the uncrosslinked slab S' toward the belt molding die 30 and heating it in this way, the uncrosslinked rubber composition sheet 21' is passed between the cords 22, and the belt molding die 30 is pressed while pressing the tooth reinforcing cloth 23. , flow into each of the plurality of tooth forming grooves 31 and bridge them. At the same time, the core wire 22 and the tooth reinforcing fabric 23 are combined and integrated, and finally a cylindrical belt slab S is formed as shown in FIG.

<Finishing process>
The interior of the vulcanization can is decompressed to release the seal, the belt slab S formed between the belt mold 30 and the rubber sleeve 32 is removed from the mold, and the toothed belt 18 according to the embodiment is cut into rings. get

Next, the material and manufacturing method of the pulley will be described.
Examples of the material of the pulley include stainless steel.
The pulley can be manufactured using a conventionally known method. For example, a dedicated hob cutter is made according to the shape of the tooth groove of the pulley, then the metal material is subjected to gear cutting using this hob cutter, and if necessary, drilling, outer shape processing, flange mounting, etc. are performed. It can be manufactured by doing.

EXAMPLES Hereinafter, the embodiments of the present invention will be described more specifically with reference to examples, but the embodiments of the present invention are not limited to the following examples.
Here, a transmission system was produced and a noise test was conducted.

(Examples 1 to 4 and Comparative Example 1)
Toothed belts constituting the power transmission belts of Examples and Comparative Examples were produced.
In the toothed belts according to the respective examples and comparative examples, the same material was used for the back rubber portion, the tooth rubber portion, the core wire, and the tooth portion reinforcing cloth.
The belt teeth were helical teeth with a tooth pitch of 2 mm, and the twist angle of the helical teeth was 5 degrees.

A specific shape of the toothed belt is as follows.
- Example 1: A toothed belt having belt teeth 20A shown in Fig. 6 was produced. Here, the tooth height was 0.80 mm, and the total thickness of the belt was 2.1 mm.
Example 2: Same as Example 1 (see FIG. 11).
Example 3: Same as Example 1 (see FIG. 12).
Example 4: Same as Example 1 (see FIG. 13).
- Comparative Example 1: Same as Example 1 (see Fig. 14).
The total thickness of the belt is the sum of the thickness of the back rubber portion, the thickness of the tooth reinforcing fabric, and the tooth height.

Each toothed belt was produced by the method described above (see FIGS. 7 to 10).
EPDM was used as a constituent material of the back rubber portion and the tooth rubber portion of the toothed belt. A glass fiber having an outer diameter of φT=0.33 mm and φW=0.33 mm was used as the cord.
As the tooth reinforcing cloth, a cloth having 66 nylon as warp and weft was used.
The width of the belt was set to 20 mm and the circumferential length of the belt was set to 330 mm when the compression ratio was 0%.

Stainless steel pulleys constituting the transmission belts of Examples and Comparative Examples were produced.
The above pulleys were manufactured through a manufacturing process including gear cutting using a dedicated hob cutter manufactured according to the tooth groove shape of each of the pulleys of Examples and Comparative Examples.
The manufactured drive pulleys of both the example and the comparative example had an addendum circle radius of 12.5 mm and a number of teeth of 40T. The driven pulleys produced in both the example and the comparative example had an addendum circle radius of 34.8 mm and a number of teeth of 110T. The shape of the pulley groove of the driving pulley and the shape of the pulley groove of the driven pulley are the same.

Specific shapes of the pulleys produced in each of Examples and Comparative Examples are as follows.
- Example 1: It is 13 A of pulley grooves shown in FIG. The dimensions of the pulley groove 13A were Hg=0.80 mm, R1=1.325 mm, a=0.172 mm, and Bg=1.300 mm in the tooth groove shape dimensions shown in FIG.
FIG. 15 is a diagram showing the dimensions of the pulley groove, which complies with JIS B 1857-2.

- Example 2: It is 43 A of pulley grooves shown in FIG. The dimensions of the pulley groove 43A were Hg=0.76 mm, R1=1.300 mm, a=0.172 mm, and Bg=1.300 mm in the tooth groove shape dimensions shown in FIG. In FIG. 11, X21 to X25 are intersection points between the belt teeth 20A and the pulley grooves 43A.

- Example 3: It is 53 A of pulley grooves shown in FIG. The dimensions of the pulley groove 53A were Hg=0.82 mm, R1=1.289 mm, a=0.132 mm, and Bg=1.300 mm in the tooth groove shape dimensions shown in FIG. In FIG. 12, X31 to X33 are intersection points between the belt teeth 20A and the pulley grooves 53A.

- Example 4: It is 63 A of pulley grooves shown in FIG. The dimensions of the pulley groove 63A were Hg=0.74 mm, R1=1.325 mm, a=0.172 mm, and Bg=1.300 mm in the tooth groove shape dimensions shown in FIG. In FIG. 13, X41 to X43 are intersections between the belt teeth 20A and the pulley grooves 63A.

- Comparative example 1: It is 73 A of pulley grooves shown in FIG. The dimensions of the pulley groove 73A were groove depth=0.87 mm, groove width=1.09 mm, and tooth base arc=0.65 mm. In FIG. 14, X51 to X53 are intersections between the belt teeth 20A and the pulley grooves 73A.
The width of each of the drive pulley and the driven pulley was set to 22 mm.

(Evaluation method)
Using the toothed belt 48, the drive pulley 42 and the driven pulley 44 prepared in each of the examples and the comparative examples, the toothed belt 48 is wound around a biaxial pulley having the drive pulley 42 and the driven pulley 44, A transmission system for evaluation shown in FIGS. 16(a) and 16(b) was constructed.
The SW (set weight) was fixed so that the belt tension was 100N. The speed reduction ratio was set to 2.8.
The noise level was measured using a precision sound level meter (manufactured by Rion, product name NL-52) having a sound collecting microphone 45 . At this time, the sound collecting microphone 45 was installed at a position 25 mm laterally (in the belt width direction) from the side surface of the toothed belt 48 and 20 mm away from the center of the drive pulley toward the center of the driven pulley.
In this evaluation, the noise level average value of the primary meshing noise measured when the rotational speed was changed from 500 rpm to 2000 rpm was used as the measured value.

Table 1 and FIG. 17 show the relationship between the belt teeth 20A and the pulley grooves and the noise level measurement results.

[Appendix]
The toothed belts of Reference Inventions 1 to 3 and the transmission systems of Reference Inventions 4 to 6, which are specified by the following constituent requirements, can also suppress noise during operation in the same manner as the toothed belts and transmission systems described above.
(Reference Invention 1)
A toothed belt in which belt teeth are provided at a constant pitch in the longitudinal direction of the belt,
The belt teeth are provided so as to mesh with a pulley having pulley grooves provided at a constant pitch on the periphery,
The tooth profile of the belt teeth is an H tooth profile, and the tooth groove profile of the pulley groove is an S tooth profile,
When the contour shape of the belt tooth viewed from the side is superimposed on the contour shape of the pulley groove viewed from the side at a position that satisfies the following condition, the contour of the contour shape viewed from the side of the belt tooth and the contour of the pulley groove when viewed from the side are obtained. A toothed belt having three or five points of intersection with a contour line when viewed from the side.
Conditions: A position where the center line of the belt tooth and the center line of the pulley groove coincide, and the intersection point of the contour line of the belt tooth and the center line coincides with the intersection point of the contour line and the center line of the pulley groove.

(Reference Invention 2)
The toothed belt of Reference Invention 1,
In the contour shape of the belt tooth viewed from the side, the distance from the center line of the belt tooth to the pressure surface is equal to or greater than the distance from the center line of the pulley groove to the pressure surface, and A toothed belt configured such that two pressure surfaces and tooth tips are in contact with the pulley grooves when meshed.

(Reference invention 3)
The toothed belt of Reference Invention 1 or 2,
A toothed belt, wherein a ratio of the tooth height of the belt teeth to the depth of the pulley grooves is 100% or more and 110% or less.

(Reference invention 4)
A transmission system comprising a toothed belt in which belt teeth are provided at a constant pitch in the longitudinal direction of the belt and a pulley in which pulley grooves are provided at the periphery at a constant pitch so as to mesh with the belt teeth,
The tooth profile of the belt teeth is an H tooth profile, and the tooth groove profile of the pulley groove is an S tooth profile,
When the contour shape of the belt tooth viewed from the side is superimposed on the contour shape of the pulley groove viewed from the side at a position that satisfies the following condition, the contour of the contour shape viewed from the side of the belt tooth and the contour of the pulley groove when viewed from the side are obtained. A transmission system having a shape such that there are three or five points of intersection with a contour line in a contour shape viewed from the side.
Conditions: A position where the center line of the belt tooth and the center line of the pulley groove are aligned, and the intersection point of the contour line of the belt tooth and the center line and the intersection point of the contour line and the center line of the pulley groove are coincident.

(Reference Invention 5)
The transmission system of Reference Invention 4,
In the contour shape of the belt tooth viewed from the side, the distance from the center line of the belt tooth to the pressure surface is equal to or greater than the distance from the center line of the pulley groove to the pressure surface, and A transmission system configured such that when engaged, two pressure surfaces and a tooth tip contact the pulley groove.

(Reference invention 6)
The transmission system of Reference Invention 4 or 5,
The transmission system, wherein a ratio of the tooth height of the belt teeth to the depth of the pulley grooves is 100% or more and 110% or less.

10 transmission system 12, 42 drive pulley 13, 13A, 15, 43A, 53A, 63A, 73A pulley groove 13B pulley tooth 14, 44 driven pulley 18, 48 toothed belt 20A, 120A belt tooth 20B tooth base 21 belt body 22 core Wire 23 Tooth Reinforcement Cloth 30 Belt Mold 31 Tooth Forming Groove 32 Rubber Sleeve 45 Sound Collecting Microphone 111 Back Rubber 112 Tooth Rubber

Claims (6)

A toothed belt in which belt teeth are provided at a constant pitch in the longitudinal direction of the belt,
The belt teeth are provided so as to mesh with a pulley having pulley grooves provided at a constant pitch on the periphery,
The length of the contour line in the contour shape of the belt tooth viewed from the side is longer than the length of the contour line of the contour shape viewed from the side of the pulley groove,
The maximum height of a point on the contour line of the belt tooth is the height of the intersection of the contour line of the belt tooth and the center line of the belt tooth,
In the contour shape of the belt tooth viewed from the side, the distance from the center line of the belt tooth to the pressure surface is equal to or greater than the distance from the center line of the pulley groove to the pressure surface, and
The belt teeth are configured such that two pressure surfaces and tooth tips are in contact with the pulley grooves when meshing with the pulley grooves.
toothed belt. When the contour shape of the belt tooth viewed from the side is superimposed on the contour shape of the pulley groove viewed from the side at a position that satisfies the following condition, the contour of the contour shape viewed from the side of the belt tooth and the contour of the pulley groove when viewed from the side are obtained. 2. The toothed belt according to claim 1, which has three or five points of intersection with the contour line when viewed from the side.
Conditions: A position where the center line of the belt tooth and the center line of the pulley groove are aligned, and the intersection point of the contour line of the belt tooth and the center line and the intersection point of the contour line and the center line of the pulley groove are coincident. The toothed belt according to claim 1 or 2, wherein a ratio of the tooth height of the belt teeth to the depth of the pulley grooves is 100% or more and 110% or less. A transmission system comprising a toothed belt in which belt teeth are provided at a constant pitch in the longitudinal direction of the belt and a pulley in which pulley grooves are provided at the periphery at a constant pitch so as to mesh with the belt teeth,
The length of the contour line in the contour shape of the belt tooth viewed from the side is longer than the length of the contour line of the contour shape viewed from the side of the pulley groove,
The maximum height of a point on the contour line of the belt tooth is the height of the intersection of the contour line of the belt tooth and the center line of the belt tooth,
In the contour shape of the belt tooth viewed from the side, the distance from the center line of the belt tooth to the pressure surface is equal to or greater than the distance from the center line of the pulley groove to the pressure surface, and
The belt teeth are configured such that two pressure surfaces and tooth tips are in contact with the pulley grooves when meshing with the pulley grooves.
transmission system. When the contour shape of the belt tooth viewed from the side is superimposed on the contour shape of the pulley groove viewed from the side at a position that satisfies the following condition, the contour of the contour shape viewed from the side of the belt tooth and the contour of the pulley groove when viewed from the side are obtained. 5. The transmission system according to claim 4 , wherein the profile is shaped such that there are three or five points of intersection with the contour line in the contour shape viewed from the side.
Conditions: A position where the center line of the belt tooth and the center line of the pulley groove are aligned, and the intersection point of the contour line of the belt tooth and the center line and the intersection point of the contour line and the center line of the pulley groove are coincident. The transmission system according to claim 4 or 5 , wherein a ratio of the tooth height of the belt teeth to the depth of the pulley grooves is 100% or more and 110% or less.

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