Synchronous drive belt and assembly comprising such belt and associated pulley

Abstract

A synchronous drive belt (100) has an elastomer-based body (102) comprising a back portion (104), a ventral portion (106), and an assembly of tensile cords (110) between the back portion (104) and the ventral portion (106), the ventral portion having: a plurality of transverse teeth (112, 112 '), each transverse tooth (112, 112') having a first profile (116) in cross section, the first profile is provided with two inclined side faces (117) which are connected through at least one rounded part, and each transverse tooth is provided with a tooth height H1; and a plurality of longitudinal teeth (114, 114 '), each longitudinal tooth extending substantially perpendicular to said transverse teeth between two transverse teeth and each longitudinal tooth in cross section having a second profile (118) with two inclined flanks (119) connected by at least one rounded portion, each longitudinal tooth having a non-zero tooth height H2, the non-zero tooth height is smaller than or equal to the tooth height H1.

Description

Technical Field

[0001] The present invention relates to a synchronous drive belt. The present invention also relates to an assembly including a belt and at least one associated pulley. The present invention also relates to a method of manufacturing such a belt. Background Art

[0002] Generally speaking, power transmission by means of a belt is very common and covers a wide range of applications, such as in the automotive industry, conveying objects, or the transmission of a pedal bicycle (commonly known as a bicycle).

[0003] Some applications require the transmission of very high torques. Not all types of belts (e.g., type, i.e., ridged in the longitudinal direction of the belt) necessarily have the performance levels required for such applications. Synchronous systems are preferred, i.e., synchronous belts having transverse teeth and corresponding pulleys are preferred. This is especially true for bicycle applications.

[0004] However, these synchronous drive systems require that the axes of rotation be perfectly parallel and the pulleys be correctly aligned. Otherwise, there is a risk that the belt will move laterally on the pulley, resulting in damage and / or the belt coming off the pulley.

[0005] To avoid these lateral movements, it may be useful for the drive system to include guiding means. Some solutions involve providing flexible elements (flasques) on the pulleys on both sides of the belt. However, the belt tends to rub against these elements, thereby accelerating wear and preventing the discharge of foreign matter such as water or gravel.

[0006] Other solutions propose machining the teeth of the synchronous belt centrally to define a groove that will be placed on a corresponding material web provided at the center of the pulley that mates with the belt. This is proposed, for example, in document EP - B1 - 3 478 561.

[0007] However, this principle has limitations in terms of the design of the pulley and the machining of the teeth of the belt. In addition, the grooves formed on the belt by this machining may be damaged by the entry of foreign matter during operation. When such a system is used in bicycle applications, these foreign matters may be, for example, mud or gravel.

[0008] Other solutions are contrary to the first solution, i.e., in addition to the synchronous teeth, the belt includes at least one web that engages in a groove provided in the corresponding pulley. Such a configuration is proposed, in particular, in document WO - A1 - 2021 / 180678.

[0009] Furthermore, both documents EP-B1-3 478 561 and WO-A1-2021 / 180678 disclose a synchronous belt as follows: the transverse teeth of the synchronous belt all have rounded tops, in particular an overall arcuate profile. Whether in the forward direction (on the pulley) or in the reverse direction (on the belt), the webs only act as lateral stops for the belt.

[0010] Document CN-U-208 651 535 discloses a synchronous belt as follows: the transverse teeth of the synchronous belt all have a right-angled trapezoidal profile. This document also discloses V-shaped longitudinal teeth between the respective transverse teeth.

[0011] Generally speaking, in order to maximize the torque transmission between two pulleys, the belt must be placed on the pulleys with the largest possible contact surface, while limiting the mechanical stresses associated especially with belt winding and the shape of the teeth.

[0012] The action of such stresses exacerbates the deformation of the teeth of the belt and even leads to the appearance of cracks, especially at the tooth roots, thus accelerating the degradation of the belt.

[0013] Another object of the present invention is to provide a synchronous drive belt as follows: the synchronous drive belt does not have at least one of the above-mentioned multiple disadvantages.

[0014] Another object of the present invention is to provide a synchronous drive belt as follows: the synchronous drive belt has improved performance in terms of the torque transmitted between two pulleys. Summary of the Invention

[0015] Therefore, a synchronous drive belt is proposed, which comprises an elastomer-based body, the elastomer-based body comprising a dorsal part, a ventral part and a component of tensile cords located between the dorsal part and the ventral part. The ventral part, on the one hand, has a plurality of transverse teeth, each transverse tooth having in cross-section a first profile, the first profile having two inclined sides converging towards each other in the direction of the top of the transverse tooth, the sides of the transverse tooth being connected by at least one rounded part, each transverse tooth having a tooth height H1, and the ventral part, on the other hand, having a plurality of longitudinal teeth, each longitudinal tooth extending substantially perpendicular to the transverse teeth between two transverse teeth and having in cross-section a second profile, the second profile having two inclined sides converging towards each other in the direction of the top of the longitudinal tooth, the sides of the longitudinal tooth being connected by at least one rounded part, each longitudinal tooth having a tooth height H2, the non-zero height H2 being less than or equal to the tooth height H1.

[0016] Thus, the present invention ensures an increase in the transmissible torque and its stability. In fact, in use, the contact surface between the belt and the pulley configured to receive the belt is high due to the profile of the teeth, in particular due to the longitudinal teeth as follows: these longitudinal teeth not only have the function of guiding the belt on the pulley, but also, by the shape of their profile, participate in the transmission of torque together with the transverse teeth. The presence of the cords increases the tensile modulus of the belt, and thus the transmissible torque can be controlled.

[0017] According to the present invention, the belt may comprise one or more of the following features, which may be used alone or in combination with each other:

[0018] - The non-zero tooth height H2 of each longitudinal tooth is strictly less than the tooth height H1 of each transverse tooth,

[0019] - The tooth height H2 of each longitudinal tooth satisfies: 0.4×H1 ≤ H2 ≤ 0.8×H1,

[0020] - Each transverse tooth has a trapezoidal profile with rounded corners in cross-section,

[0021] - The first profile of each transverse tooth comprises: two convex top portions, which are located on both sides of the top portion; and two concave portions, which are located on both sides of the base of the transverse tooth,

[0022] - Each convex top portion of the first profile has an approximate radius of curvature between 0.6 mm and 1.4 mm, and each concave portion has a radius of curvature between 0.6 mm and 1.4 mm,

[0023] - The second profile of each longitudinal tooth comprises: two concave portions, which are located on both sides of the base of the longitudinal tooth; and a tooth top, which is convex,

[0024] - Each concave portion of the second profile has a radius of curvature between 0.8 mm and 1.6 mm, and the said top of the second profile has a radius of curvature between 0.8 mm and 1.6 mm,

[0025] - The second profile of each longitudinal tooth is a trapezoidal profile with rounded corners,

[0026] - The synchronous belt comprises a coating, which is arranged at the level of the outer surfaces of the plurality of transverse teeth and the plurality of longitudinal teeth,

[0027] - The elastomer-based body of the belt is made of a material selected from ethylene-α-olefin or polyurethane, and the coating is a textile material or an elastomeric thermoplastic film,

[0028] - Each cord of the assembly of tensile cords is made of aramid, polyester, glass fiber or carbon fiber or a combination thereof,

[0029] - These transverse teeth are distributed at an interval of 11 mm.

[0030] The present invention also relates to an assembly, which comprises at least one pulley and a synchronous drive belt as described above. Each pulley comprises:

[0031] - Two rows of circumferential tooth portions, which are parallel to each other and are configured to receive the tooth recesses of a plurality of transverse teeth of the belt, and

[0032] - A circumferential groove, which separates the two rows of circumferential tooth portions and is configured to receive a plurality of longitudinal teeth of the belt.

[0033] According to the present invention, the assembly may comprise one or more of the following features, which may be used alone or in combination with each other:

[0034] - The assembly comprises a first pulley having a given size and a second pulley having a size different from that of the first pulley.

[0035] - The assembly comprises identical first and second pulleys.

[0036] - Each row of circumferential tooth portions comprises tooth recesses, and the depth P1 of the tooth recesses is greater than the height H1 of the transverse teeth of the belt.

[0037] - The depth P2 of the longitudinal groove is greater than the height H2 of the longitudinal teeth of the belt.

[0038] - Each pulley is made of a material selected from steel, aluminum or plastic.

[0039] The present invention also relates to a method for manufacturing a synchronous drive belt as described above, the method comprising the following steps:

[0040] - Forming a belt blank from a belt material around a cylindrical mandrel;

[0041] - Removing the blank from the mandrel;

[0042] - Inserting the blank into a cylindrical mold, which comprises a female pattern of transverse teeth and longitudinal teeth to be formed on the belt on its inner cylindrical wall;

[0043] - Pressing the blank against the mold by an expandable rubber bladder and heating the mold to vulcanize the belt blank;

[0044] - Demolding the vulcanized blank; and

[0045] - Cutting the vulcanized blank to form a belt. Description of the Drawings

[0046] The present invention will be better understood with the aid of the following description, which is given by way of example only and with reference to the accompanying drawings, in which:

[0047] Figure 1 shows a partial schematic perspective view of a belt according to the present invention,

[0048] Figure 2 shows Figure 1 a schematic cross-sectional view of the belt shown in

[0049] Figure 3 shows a schematic cross-sectional view of another embodiment of a synchronous drive belt according to the present invention,

[0050] Figure 4 shows Figure 1 a schematic sectional view of the belt in

[0051] Figure 5 shows a schematic sectional view of another embodiment of a synchronous drive belt according to the present invention,

[0052] Figure 6 shows a schematic view of a step in a method of manufacturing a belt according to the present invention, in particular positioning a belt blank in a mold,

[0053] Figure 7 shows Figure 6 a schematic longitudinal section of details of the step of the method in

[0054] Figure 8 shows a schematic view of another step in a method of manufacturing a belt according to the present invention, in particular positioning an expandable bladder inside the blank,

[0055] Figure 9 shows Figure 8 a schematic longitudinal section of details of the step of the method in

[0056] Figure 10 shows a schematic view of another step in a method of manufacturing a belt according to the present invention, in particular printing a mold pattern on the blank,

[0057] Figure 11 shows Figure 10 a schematic longitudinal section of details of the step of the method in

[0058] Figure 12 shows a schematic view of another step in a method of manufacturing a belt according to the present invention, in particular removing the molded blank,

[0059] Figure 13 shows a schematic view of a tensile strength test of a belt according to the present invention,

[0060] Figure 14 A schematic perspective view of a component according to the present invention is shown, the component including at least one pulley and a synchronous drive belt.

[0061] Figure 15 is Figure 14 a schematic side view of the component shown in

[0062] Figure 16 and shows Figure 14 a schematic cross-sectional view of the component shown in Detailed Description

[0063] Figure 1 A perspective view of an embodiment of a synchronous drive belt 100 according to the present invention is shown.

[0064] The synchronous drive belt 100 includes a component of tensile cords 110 and an elastomer-based body 102.

[0065] The elastomer-based body 102 includes a dorsal part 104. The elastomer-based body 102 further includes a ventral part 106 formed by a plurality of teeth 112, 112', 114, 114'. The plurality of teeth 112, 112', 114, 114' includes, on the one hand, a plurality of transverse teeth 112, 112' and, on the other hand, a plurality of longitudinal teeth 114, 114'. The plurality of transverse teeth 112, 112' and the plurality of longitudinal teeth 114, 114' each include an outer surface configured to at least partially cooperate with a tooth recess of a pulley.

[0066] Each transverse tooth 112, 112' also has a first profile 116 in cross-section, the first profile having two inclined sides 117 that converge towards each other in the direction of the top of the tooth, and the two inclined sides 117 are also connected at the level of the top by at least one rounded portion.

[0067] "Rounded" means that the first profile 116 of the transverse teeth 112, 112' has a shape defining at least one curvature.

[0068] In one embodiment, as Figures 2 to 4 shown, the first profile 116 may be a trapezoid with rounded corners.

[0069] "Trapezoid" is understood to mean that the first profile 116 of the transverse teeth 112, 112' has a trapezoidal shape, i.e., a deformed trapezoid or a trapezoid. Thus, the top of each transverse tooth 112, 112' defines a top portion 116a of non-zero size, which is parallel or not parallel to the imaginary base 116b of the transverse tooth 112, 112' (in Figure 2shown in dashed lines), the base itself is parallel to the dorsal part 104 of the belt 100. In other words, the top of each transverse tooth 112, 112' defines a top part 116a of non-zero size that is parallel or not parallel to the dorsal part 104 of the belt 100. It should be understood that the dorsal part 104 of the belt 100 is substantially flat, and the top part 116a is also substantially flat.

[0070] "Round corner" is understood to mean that the first profile 116 of the transverse teeth 112, 112' includes, on the one hand, at least one angle describing a convex curvature at the level of the top of the transverse teeth 112, 112', called the convex top part 116c, and / or, on the other hand, at least one angle describing a concave curvature at the level of the tooth recess 120, called the concave part 116d.

[0071] In other words, the first profile 116 of the transverse teeth 112, 112' advantageously includes a substantially flat top part 116a of the tooth, at least one convex top part 116c, and at least one concave part 116d of the bottom tooth recess 120.

[0072] Typically, the top part 116a of the transverse teeth 112, 112' can have a non-zero size between 3 mm and 6 mm.

[0073] Typically, the convex top part 116c is the result of a cubic spline of several points or nodes of the first profile 116. In this way, equal convexity on both sides of each point is defined. The approximate radius of curvature R1 of the convex top part 116c can also be determined.

[0074] Typically, the convex top part 116c has an approximate radius of curvature R1 that can be between 0.6 mm and 1.4 mm.

[0075] The concavity of the concave part 116d depends directly on the spline obtained and described above. In other words, the radius of curvature R2 of the concave part 116d depends on the spline.

[0076] Typically, the radius of curvature R2 of the concave part 116d can be between 0.6 mm and 1.4 mm.

[0077] Each transverse tooth 112, 112' has a symmetry axis Y. It should be understood that when the first profile 116 of each transverse tooth 112, 112' is a trapezoid with a round corner, the first profile includes two convex top parts 116c located on both sides of the top part 116a and two concave parts 116d located on both sides of the base 116b.

[0078] In one embodiment, the first profile 116 of each lateral tooth 112, 112' can be defined as the component of a line segment between two points, the radius double tangent between this line segment and the base 116b of the tooth. In other words, the first profile 116 can be defined as the concave portion 116d and a spline tangent to both: this line segment; and a straight line tangent to the top of the lateral teeth 112, 112'.

[0079] In use, this type of profile allows the belt 100 to transmit higher torque, but may result in a decrease in meshing quality. This can also reduce the stress on the lateral teeth 112, 112' and the deformation of the lateral teeth.

[0080] Each of the plurality of longitudinal teeth 114, 114' also extends between two lateral teeth 112, 112', extending substantially perpendicular to and between the two lateral teeth 112, 112'.

[0081] Each longitudinal tooth 114, 114' also has a second profile 118 in cross-section, which has two inclined sides 119 converging towards each other in the direction of the top of the tooth, and these two sides 119 are also connected by at least one rounded portion at the level of the top. Overall, the sides 119 can be, for example, substantially V-shaped or U-shaped.

[0082] As mentioned above, "rounded" is understood to mean that the second profile 118 of the longitudinal teeth 114, 114' has a shape defining at least one curvature.

[0083] Each longitudinal tooth 114, 114' can have a top with a top portion 118a defining a zero dimension. In this case, the top of the longitudinal teeth 114, 114' is convex and presents an arc.

[0084] In this case, the second profile 118 of the longitudinal teeth 114, 114' advantageously includes at least one concave portion 118d of the bottom tooth recess 120 and a convex tooth top 118c.

[0085] Typically, the radius of curvature R2' of the concave portion 118d of the bottom tooth recess 120 is between 0.8 mm and 1.6 mm.

[0086] Typically, the radius of curvature R3 of the convex tooth top 118c is between 0.8 mm and 1.6 mm.

[0087] Each longitudinal tooth 114, 114' has a symmetry axis. Thus, it can be understood that the second profile 118 of each longitudinal tooth 114, 114' includes a convex tooth top 118c and two concave portions 118d located on both sides of the base 118b.

[0088] Alternatively, not shown, the second profile 118 of each longitudinal tooth 114, 114' can be a trapezoid with rounded corners, i.e., substantially similar to the first profile 116 described above. In this case, the top of each longitudinal tooth 114, 114' defines a top portion 118a of non-zero dimension, which is parallel or non-parallel to the imaginary base 118b of the longitudinal tooth 114, 114', and the base itself is parallel to the dorsal portion 104 of the belt 100. In other words, the top of each longitudinal tooth 114, 114' defines a top portion 118a of non-zero dimension, which is parallel or non-parallel to the dorsal portion 104 of the belt 100. It should be understood that the dorsal portion 104 of the belt 100 is substantially flat, and the top portion 118a is also substantially flat. And at least one curvature is defined on the one hand by at least one angle that describes the curvature in a convex manner at the level of the top of the longitudinal tooth 114, 114', and / or on the other hand by at least one angle that describes the curvature in a concave manner at the level of the tooth recess 120. Since the second profile 118 of each longitudinal tooth 114, 114' has a symmetry axis Y', it can be understood that the second profile 118 of each longitudinal tooth 114, 114' includes two convex top portions located on both sides of the top portion 118a and two concave portions 118d located on both sides of the base 118b.

[0089] In addition, the inclined sides 119 of each longitudinal tooth 114, 114' connected by rounded portions form an angle therebetween, and the angle of this angle is between 30° and 50°. Advantageously, the value of this angle is between 30° and 45°, and preferably between 35° and 45°.

[0090] In addition, the transverse teeth 112, 112' have a tooth height H1, and the longitudinal teeth 114, 114' have a tooth height H2. The non-zero tooth height H2 of the longitudinal teeth 114, 114' is less than or equal to the tooth height H1 of the transverse teeth 112, 112'.

[0091] Advantageously, the non-zero tooth height H2 of the longitudinal teeth 114, 114' is strictly less than the tooth height H1 of the transverse teeth 112, 112'.

[0092] The tooth height H2 of the longitudinal teeth 114, 114' is lower than the tooth height H1 of the transverse teeth, which improves the flexural flexibility of the belt 100. The increased flexibility makes it easier for the belt 100 to be wound around a pulley with a small diameter. For example, a pulley with a small diameter is particularly popular for bicycle applications.

[0093] Typically, the tooth height H1 of the transverse teeth 112, 112' can be between 2.5 mm and 5 mm.

[0094] Typically, when the tooth height H2 of the longitudinal teeth 114, 114' is strictly less than the tooth height H1 of the transverse teeth 112, 112', the tooth height H2 of the longitudinal teeth can satisfy: 0.4×H1 ≤ H2 ≤ 1.0×H1. Advantageously, the tooth height H2 satisfies: 0.4×H1 ≤ H2 ≤ 0.9×H1, even more advantageously satisfies: 0.4×H1 ≤ H2 ≤ 0.8×H1, and preferably satisfies: 0.5×H1 ≤ H2 ≤ 0.8×H1.

[0095] It has also been observed that when the tooth height H2 is greater than or equal to 0.4×H1, the good lateral guidance of the belt is improved, and when the tooth height H2 is less than or equal to 0.8×H1, good winding of the belt on the pulley is ensured.

[0096] In use, the transverse teeth 112, 112' are used to transmit torque, and due to the presence of the inclined sides 117 connected to each other by at least one rounded portion, this torque transmission is greater. The longitudinal teeth 114, 114' transmit torque in addition to automatically centering the belt 100. As previously mentioned, the angle formed by the side surfaces 119 introduced by the profile 118 of the longitudinal teeth 114, 114' contributes to torque transmission. In addition, the rounded shape of the profile 118 allows the belt 100 to automatically center on the pulley on which it is mounted more quickly in the case of its lateral displacement, thus improving its guidance. The presence of the longitudinal teeth 114, 114' also limits the deformation of the transverse teeth 112, 112'. Since the tooth height H2 of the longitudinal teeth 114, 114' is less than or equal to the tooth height H1 of the transverse teeth 112, 112', both torque transmission and guidance are improved. If the tooth height H2 is greater than the tooth height H1, constraints may occur, especially a reduction in the flexibility of the belt 100 and a mismatch with the pulley (the belt 100 is configured to cooperate with this pulley).

[0097] The transverse teeth 112, 112' of the belt 100 can be distributed at intervals of 8 mm, 11 mm or 14 mm. Advantageously, the transverse teeth 112, 112' of the belt 100 are distributed at an interval of 11 mm.

[0098] The belt 100 also includes a component of the tensile cord 110. The cord 110 is embedded in the body 102 between the dorsal portion 104 and the ventral portion 106 of the body 102. The cord 110 increases the tensile modulus of the belt 100. Thus, the cords extend along the length of the belt and are arranged adjacent to each other across the width of the body 102. In particular, the cords 110 of the cord assembly can be made of a material selected from aramid, polyester, glass fiber or carbon fiber or a combination thereof. Thus, for the application in question, the cords allow greater torque transmission while maintaining a very limited elongation of the belt 100.

[0099] The construction of each cord 110, the number of cords 110 arranged across the width of the belt 100, and the choice of the material constituting the cords are variable and depend on the tensile modulus required for the belt 100 to ensure torque transmission while restricting elongation of the belt 100. The general effect of such cords 110 is to allow for higher torque transmission.

[0100] Advantageously, the tensile modulus of the belt 100 is chosen between 10,000 N / mm belt width (Newtons per millimeter of belt width) and 30,000 N / mm belt width, measured linearly between 0% and 1% elongation of the belt.

[0101] As Figure 3 and Figure 5 shown, the synchronous belt 100 may also include a coating 122 provided at the level of the outer surface of the plurality of teeth 112, 112', 114, 114'. The coating 122 is particularly suitable for strengthening the tooth feet, i.e., the concave portions 116d of the lateral teeth 112, 112' and the concave portions 118d of the longitudinal teeth 114, 114'.

[0102] The coating 122 may generally be made of a textile material selected from, but not limited to, knitted fabrics, woven fabrics, or non-woven fabrics. In this case, the coating 122 may be made of a material generally selected from polyamide (PA) or a polyamide-elastomer mixture.

[0103] Alternatively, the coating 122 may be an elastomeric thermoplastic film having a polymer matrix that is a combination of a thermoplastic matrix and an elastomeric matrix. The elastomeric portion of the elastomeric thermoplastic is advantageously an ethylene-α-olefin, such as ethylene-propylene-monomer (EPM) or ethylene-propylene-diene monomer (EPDM). The thermoplastic matrix of the elastomeric thermoplastic is advantageously an olefin thermoplastic, such as low-density polyethylene.

[0104] The thickness of such a thermoplastic elastomer film may be between 50 μm (micrometers) and 200 μm

[0105] The elastomer-based body 102 of the belt 100 may be made of a material selected from, but not limited to, ethylene-α-olefins such as ethylene-propylene-monomer (EPM) or ethylene-propylene-diene monomer (EPDM), hydrogenated butadiene-acrylonitrile copolymer (HNBR), or polyurethane (PU).

[0106] Examples of embodiments of the synchronous belt according to the invention

[0107] Hereinafter, reference Figures 2 to 5 , Figures 2 to 5 shows a specific example of an embodiment of the belt 100.

[0108] The elastomer-based body 102 is made of peroxide-cured ethylene propylene diene monomer (EPDM) and, in this example, has a Shore A hardness of 85.

[0109] In the example of this embodiment, the belt 100 has the geometry defined and shown in Figure 2 and Figure 4 The body 102 has a thickness T of 6.5 mm measured from the dorsal part 104 to the top of the lateral teeth 112, 112' and a width of 12 mm.

[0110] The height H1 of each lateral tooth 112, 112' is 5 mm. Further, in the example of this embodiment, the first profile 116 of each lateral tooth 112, 112' is a trapezoid with rounded corners. This first profile 116 has a top part 116a of 2 mm and a convex top part 116c with an approximate radius of curvature R1 of 1.2 mm.

[0111] The height H2 of each longitudinal tooth 114, 114' is 2.2 mm. Further, the rounded second profile 118 of each longitudinal tooth 114, 114' has a concave part 118d with a radius of curvature R2' of the bottom tooth recess 120 of 1.2 mm and a convex tooth tip 118c with a radius of curvature R3 of 1.6 mm. Further, the inclined side surfaces 119 connected by at least one rounded part of the second profile 118 of each longitudinal tooth 112, 112' form an angle of 40° with each other.

[0112] The assembly of the cords 110 embedded in the body 102 includes 13 cords 110. The diameter d of the cords 110 is 0.8 mm, and the centers of the individual cords are laterally separated by a pitch p of 0.92 mm. The center of each cord 110 is also located at a distance of approximately 0.7 mm from the dorsal part 104 of the belt 100.

[0113] Each cord 110 is made of aromatic polyamide, in particular 1100×1×4 aromatic polyamide, i.e., each thread has a fineness of 1100 dtex (decitex), i.e., 1100×10 -7 kg / m (kilograms per meter), and each thread is first individually stranded before being stranded in four strands. Each cord 110 also has a Young's modulus of 30000 MPa (megapascals) or 30000 N / mm 2 (newtons per square millimeter).

[0114] Thus, the tensile modulus of the belt can be calculated and expressed as the Young's modulus of the cords 110 multiplied by the cross-sectional area of the cords 110. In the example of the illustrated embodiment, the belt 100 has 13 cords 110, where each cord 110 has a diameter d of 0.8 mm and a total cross-sectional area of approximately 6.53 mm 2Thus, the components of the cord 110 allow the tensile modulus of the belt 100 to be defined as a value of approximately 195,900 N.

[0115] In an example of this embodiment, the drive belt 100 includes a coating 122, as Figure 3 and Figure 5 shown. The coating 122 is a polyamide knitted fabric, in particular polyamide 66 with a weight of 150 g / m 2 (grams per square meter).

[0116] In an example of this embodiment, the lateral teeth 112, 112' of the belt 100 are distributed at a pitch of 11 mm. This pitch also has the advantage of optimizing torque transmission and optimizing the overall dimensions. The smaller the pitch, the smaller the torque transmitted, while the larger the pitch, the larger the overall dimensions of the teeth.

[0117] Now referring to Figures 6 to 12 and Figures 6 to 12 , steps for manufacturing the belt 100 in the above embodiment are shown.

[0118] The method for manufacturing the belt 100 according to the present invention includes:

[0119] - forming a belt blank 10 from a belt material around a cylindrical mandrel;

[0120] - removing the blank from the mandrel;

[0121] - inserting the blank 10 into a cylindrical mold 12, which includes on its inner cylindrical wall a female pattern of the lateral teeth 112, 112' and longitudinal teeth 114, 114' to be formed on the belt 100,

[0122] - pressing the blank 10 against the mold 12 by an expandable rubber bladder 14 and heating the mold 12 to vulcanize the belt blank 10;

[0123] - demolding the vulcanized blank; and

[0124] - cutting the vulcanized blank 10 to form the synchronous drive belt 100.

[0125] The belt material for forming the blank 10 is pre-placed on a cylindrical mandrel (not shown). These belt materials include the back portion 104 of the belt body 102 (in the original state), the cord 110, and the ventral portion 106 of the belt body 102 (in the original state). These belt materials may also include the coating 122 placed on the ventral portion 106 of the belt body 102. In Figure 6 and Figure 7In [description], the blank 10 has been removed from the cylindrical mandrel and inserted into the cylindrical mold 12, which includes at least one pattern on its inner cylindrical wall that is opposite to the profiles of the transverse teeth 112, 112' and longitudinal teeth 114, 114' to be formed on the belt. It should be understood that the ventral part 106 (in the original state) is positioned in contact with the mold 12.

[0126] In Figure 8 and Figure 9 In [description], the inflatable bladder 14 is located within the blank 10.

[0127] In Figure 10 and Figure 11 In [description], the inflatable bladder 14 is inflated to a pressure of 20 bar, thereby pressing the dorsal part 104 of the blank 10 (in the original state) against the mold 12 (see the arrow E in Figure 11 ). In this way, the inner wall of the mold 12 having at least one pattern (which is the negative pattern of the pattern of the teeth 112, 112', 114, 114' to be formed on the belt) forms a corresponding pattern on the outer surface of the ventral part 106 of the blank 10. At the same time, the mold 12 is heated to 182 °C to ensure the vulcanization of the dorsal part 104 and ventral part 106 configured to form the vulcanized elastomeric body 102. It should be understood that during this step, the mold 12 pattern is printed on the blank 10.

[0128] Then, the now-vulcanized blank 10 is removed from the mold, as shown in Figure 12 , and then the blank 10 is cut to the desired width to obtain the belt 100 according to the present invention.

[0129] Next, the tensile strength of the synchronous drive belt 100 produced in this way is tested. The test is carried out according to various standards, including ISO 4210-8 and the French and European standards NF EN 15194.

[0130] These standards describe the Figure 13 shown tensile strength test. In this test, the belt 100 according to the present invention is mounted on two similar or identical drive pulleys P, P'. At least one of the two pulleys P, P' rotates freely. During the test, the tensile load is gradually increased until the tensile force applied to the belt 100 reaches 4000 N. To make the force applied to the belt 100 reach 4000 N, a tensile load F of 8000 N is required.

[0131] When this threshold is reached, according to the recommendations of the standard, the belt 100 does not show cracks, fractures or delaminations.

[0132] The example ends.

[0133] Refer toFigures 14 to 16 , the present invention also relates to a component 300, which includes the synchronous belt 100 as described above and at least one pulley 200.

[0134] From a practical perspective, the component 300 can advantageously be in the form of a kit or already assembled.

[0135] Preferably, the belt 100 is configured to be mounted on two pulleys 200 (i.e., the first pulley and the second pulley) during use. On the one hand, each of these pulleys 200 includes two rows of circumferential teeth 210, 210', which are parallel to each other and are configured to receive the tooth recesses 122 of a plurality of transverse teeth 112, 112' of the belt 100. On the other hand, each of these pulleys 200 includes a circumferential groove 220, which separates the two rows of circumferential teeth 210, 210' and is configured to receive a plurality of longitudinal teeth 114, 114' of the belt 100.

[0136] Advantageously, the component 300 includes a first pulley with a given size and a second pulley (not shown) with a size different from that of the first pulley. Different sizes mean that the diameter of the second pulley is greater than or less than the diameter of the first pulley.

[0137] Advantageously, the component 300 includes the same first pulley and second pulley. The same means that the two pulleys have the same size, for example, the same diameter and rows of teeth 210, 210' with the same geometric shape.

[0138] Each pulley 200 can be made of a selected material, but the material is not limited to steel, aluminum or plastic. Each of these materials has properties that may be suitable for a predetermined application in terms of mechanical strength, density or cost.

[0139] Each row of circumferential teeth 210, 210' also includes tooth recesses 212 with a depth of P1. Advantageously, this depth P1 is greater than the height H1 of the transverse teeth 112, 112' of the belt 100.

[0140] The circumferential groove 220 in each pulley 200 also has a depth of P2. Advantageously, this depth P2 is greater than the height H2 of the longitudinal tooth 144.

[0141] The teeth in each row of circumferential teeth 210, 210' can be distributed at intervals of 8 mm, 11 mm or 14 mm.

[0142] Therefore, it can be understood that, on the one hand, there is a gap 230 between the top of each tooth 112, 112', 114, 114' and the tooth recess 210 of the pulley 200, and on the other hand, there is a gap 230 between the top of each tooth 112, 112', 114, 114' and the bottom of the groove 220. The advantage of this gap 230 is that it serves as a means of discharging foreign matter, such as mud, water or stones, which may enter the assembly 300 during operation, and more particularly between the pulley 200 and the belt 100. Since these foreign matters are more easily discharged, the risk of wear of the belt 100 is reduced.

[0143] In view of the above, it is clear that the belt according to the present invention allows an increase in the torque that can be transmitted by the belt and its stability. In fact, in use, due to the shape of the teeth of the belt, the contact surface between the transverse teeth and the longitudinal teeth of the belt and the teeth of the pulley is large. This high contact area and the presence of the cords increase the tensile modulus of the belt, so that the torque that can be transmitted and the degree of deformation of the belt can be controlled, thus reducing the wear of the belt over time and therefore increasing the service life of the belt. In addition, the longitudinal teeth guide the belt on the pulley and prevent it from moving laterally.

[0144] Another advantage is that when the belt is mounted on the pulley of the assembly according to the present invention, it allows external elements (such as water, dirt, mud or stones) that may enter the tooth recesses of the pulley to be removed.

Claims

1. A synchronous drive belt (100) comprising an elastomer-based body (102), the elastomer-based body comprising a dorsal part (104), a ventral part (106), and a component of tension cords (110) located between the dorsal part (104) and the ventral part (106), the ventral part (106) having on the one hand a plurality of transverse teeth (112, 112'), each transverse tooth (112, 112') having in cross-section a first profile (116), the first profile having two inclined sides (117) converging towards each other in the direction of the top of the transverse tooth (112, 112'), the sides (117) of the transverse tooth being connected by at least one rounded part, each transverse tooth having a tooth height H1, and the ventral part (106) having on the other hand a plurality of longitudinal teeth (114, 114'), each longitudinal tooth (114, 114') extending substantially perpendicular to the transverse teeth between two transverse teeth (112, 112') and having in cross-section a second profile (118), the second profile having two inclined sides (119) converging towards each other in the direction of the top of the longitudinal tooth (114, 114'), the sides (119) of the longitudinal tooth being connected by at least one rounded part, each longitudinal tooth having a tooth height H2, the non-zero tooth height H2 being less than or equal to the tooth height H1.

2. The belt (100) according to claim 1, wherein, The tooth height H2 of each longitudinal tooth (114, 114') satisfies: 0.4×H1 ≤ H2 ≤ 0.8×H1.

3. The belt (100) according to any one of claims 1 or 2, wherein, Each transverse tooth (112, 112') has in cross-section a first trapezoidal profile (116) with rounded corners.

4. The tape (100) according to claim 3, wherein, The first profile (116) of each transverse tooth (112, 112') comprises: two convex top parts (116c) located on both sides of the top part (116a); and two concave parts (116d) located on both sides of the base (116b) of the transverse tooth.

5. The belt (100) according to claim 4, wherein, Each convex top part (116c) of the first profile (116) has an approximate radius of curvature (R1) between 0.6 mm and 1.4 mm, and each concave part (116d) has a radius of curvature (R2) between 0.6 mm and 1.4 mm.

6. The belt (100) according to any one of claims 1 to 5, wherein, The second profile (118) of each longitudinal tooth (114, 114') comprises: two concave parts (118d) located on both sides of the base (118b) of the longitudinal tooth; and a tooth top (118c) which is convex.

7. The belt (100) according to claim 6, wherein, Each concave part (118d) of the second profile (118) has a radius of curvature (R2') between 0.8 mm and 1.6 mm, and the top (118c) of the second profile has a radius of curvature (R3) between 0.8 mm and 1.6 mm.

8. The belt (100) according to any one of claims 1 to 7, wherein, The second profile (118) of each longitudinal tooth (114, 114') is a trapezoidal profile with rounded corners.

9. The belt (100) according to any one of claims 1 to 8, comprising a coating (120) arranged at the level of the outer surfaces of the plurality of transverse teeth (112, 112') and the plurality of longitudinal teeth (114, 114').

10. The belt (100) according to claim 9, wherein, The elastomeric body (102) of the belt (100) is made of a material selected from ethylene - α - olefin or polyurethane, and the coating (120) is a textile material or an elastomeric thermoplastic film.

11. The belt (100) according to any one of claims 1 to 10, wherein, Each cord (110) of the assembly of tensile cords is made of aramid, polyester, glass fiber or carbon fiber or a combination thereof.

12. An assembly (300), comprising at least one pulley (200) and a synchronous drive belt (100) according to any one of claims 1 to 11, each pulley comprising: - two rows of circumferential tooth portions (210, 210') that are parallel to each other and are configured to receive the tooth recesses (122) of the plurality of transverse teeth (112, 112') of the belt (100), and - a circumferential groove (220) that separates the two rows of circumferential tooth portions and is configured to receive the plurality of longitudinal teeth (114, 114') of the belt (100).

13. The component (300) according to claim 12, wherein, Each row of circumferential tooth portions (210, 210') includes tooth recesses (212) having a depth P1 greater than the height H1 of the transverse teeth (112, 112') of the belt (100).

14. The component (300) according to any one of claims 12 or 13, wherein, The depth P2 of the longitudinal groove (220) is greater than the height H2 of the longitudinal teeth (114, 114') of the belt (100).

15. A method of manufacturing a belt (100) according to any one of claims 1 to 14, the method comprising the following steps: - forming a belt blank (10) from a belt material around a cylindrical mandrel; - removing the blank from the mandrel; - inserting the blank (10) into a cylindrical mold (12) that includes on its inner cylindrical wall a female pattern of the transverse and longitudinal teeth to be formed on the belt; - pressing the blank (10) against the mold (12) by means of an inflatable rubber bladder (14) and heating the mold to vulcanize the belt blank; - demolding the vulcanized blank; and - cutting the vulcanized blank to form the belt.

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