Toothed belt and toothed belt transmission

Abstract

The present application relates to a toothed belt characterized by comprising: a back; a core wire embedded in the back in a belt length direction, composed of a twisted cord including steel fibers; a plurality of belt teeth formed in the belt length direction on an inner peripheral side of the back; and a cover layer provided between a belt tooth bottom portion formed between the belt teeth and the core wire, the thickness of the cover layer being in a range of 0.2 to 1.0 mm, the back, the belt teeth, and the cover layer being integrally formed of a thermoplastic elastomer.

Description

Technical Field

[0001] This invention relates to toothed belts that require power transmission performance under high tension conditions in environments with relatively high loads (high torque). Background Technology

[0002] To improve efficiency in weak winds and reduce efficiency in strong winds, wind turbines adjust the blade spacing (the angle of the toothed pulley that rotates the blades around the axis) and thus the turbine's rotational speed (see reference). Figure 1 For example, Patent Document 1, Patent Document 2, and Patent Document 3 disclose methods for controlling the spacing of blades using a toothed belt-based drive (meshing transmission) method.

[0003] In these methods, because the toothed belt used for driving is located near the root of the blades, a small-amplitude oscillation often occurs near the blade root during strong winds. In this situation, due to this effect, the meshing of the toothed belt teeth with the pulley involves a small-amplitude reciprocating motion. During this reciprocating motion, if the bottom of the toothed belt teeth is forcefully pressed against the pulley, it will cause intense friction with a small amplitude, resulting in significant wear at the bottom of the teeth. Furthermore, if this progresses to the wear and breakage of the core wire embedded in the belt teeth, the belt strength decreases, and sometimes this can eventually lead to belt breakage.

[0004] Generally, in toothed belt drive mechanisms, such as lifting and conveying devices, the drive pulleys rotate and reciprocate under specified (constant) conditions. However, in wind turbine applications, the drive pulleys rotate and reciprocate under conditions that are driven by wind movement. Therefore, a special design is required, different from that for general applications. In particular, toothed belts for this purpose require wear resistance at the tooth tips relative to small-amplitude forward and backward movements (based on reciprocating motion in both directions) and strength to withstand high winds.

[0005] In this application, as a means to suppress wear at the bottom of the teeth of the toothed belt, a toothed belt drive device is disclosed in Patent Document 4, wherein the front end of the belt teeth contacts the bottom of the pulley teeth, the front end of the pulley teeth does not contact the bottom of the belt teeth, and a gap S is provided between the front end of the pulley teeth and the bottom of the belt teeth.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Chinese Utility Model No. 202370752 Specification

[0009] Patent Document 2: US Patent No. 8,684,693

[0010] Patent Document 3: International Publication No. 2013 / 156497

[0011] Patent Document 4: Japanese Patent Application Publication No. 2018-204790 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] A gap S is provided between the front end and the bottom of the aforementioned gear teeth (refer to Patent Document 4). Figure 1 In toothed belts, power is transmitted in a manner where only the front end of the teeth (tooth tip) contacts the pulley during meshing, while the bottom of the teeth does not contact the pulley (tooth tip transmission). Therefore, even in applications involving small forward and backward movements (reciprocating motion based on forward and reverse rotation), wear on the bottom of the teeth can be suppressed.

[0014] However, in terms of power transmission efficiency and the durability of the toothed section, the original meshing transmission is preferably one where both the top and bottom of the teeth are in contact with the pulley. That is, while a method where the bottom of the teeth does not contact the pulley is effective in terms of wear resistance, it is disadvantageous in terms of power transmission and the durability of the toothed section.

[0015] On the other hand, in recent years, the field of wind turbines has seen a trend towards larger scale (larger power generation capacity), which correspondingly places higher demands on toothed belts for power transmission under high tension conditions in environments with higher loads (high torque). Therefore, the tooth-top transmission method disclosed in Patent Document 4, where the tooth bottom does not contact the pulley (tooth-top transmission method), cannot keep up with power transmission under high tension conditions, and a method that is beneficial to power transmission performance and tooth durability is needed.

[0016] Furthermore, in the field of wind turbines, the installation locations are shifting from onshore to offshore. When installed offshore, rust resistance to saltwater is required.

[0017] However, in the method disclosed in Patent Document 4, since the core wire (steel cord) is positioned at the bottom of the toothed section and exposed on the bottom surface of the tooth, the steel cord may rust due to salt water. Additionally, a method is disclosed where the bottom of the toothed section is covered with reinforcing fabric (66 nylon fabric), but this may also result in rust on the steel cord due to moisture absorbed by the reinforcing fabric. Therefore, improvements are needed to ensure the rust resistance of the core wire (steel cord).

[0018] The purpose of this invention is to provide a toothed belt and a toothed belt drive device that can adapt to the high-load environment (high tension condition) of power transmission with the increasing size of wind turbines (larger power generation capacity) in recent years, and can also adapt to the rust resistance required for offshore installations (offshore wind power generation).

[0019] Technical solutions for solving the problem

[0020] This invention relates to a toothed belt, characterized by comprising:

[0021] Back;

[0022] The core wire, embedded along the length of the belt in the back, is composed of twisted cord containing steel fibers;

[0023] Multiple teeth are formed on the inner circumferential side of the back side, along the length direction of the belt; and

[0024] A cover layer is disposed between the bottom of the teeth formed between the teeth and the core wire.

[0025] The thickness of the covering layer is in the range of 0.2 to 1.0 mm.

[0026] The back, the teeth, and the cover layer are integrally formed from a thermoplastic elastomer.

[0027] According to the above structure, by providing a covering layer with a thickness of 0.2 to 1.0 mm between the bottom of the belt teeth and the core wire (on the inner circumference of the core wire), the core wire, which is composed of twisted cord containing steel fibers, is not located on the surface of the bottom of the belt teeth (the core wire is not directly exposed, and its position is isolated from the bottom of the belt teeth). Therefore, when meshing with the pulley, even if the bottom of the belt teeth contacts the front end of the pulley teeth, wear and breakage of the core wire can be suppressed. In particular, for small-amplitude forward and backward movements (reciprocating motion based on forward and reverse rotation), the covering layer can protect the core wire from wear and breakage.

[0028] In addition, since the core wire is embedded in the thermoplastic elastomer, there is no part of the core wire that comes into contact with or is exposed on the surface of the toothed bottom, which prevents the core wire (the twisted cord containing steel fibers) from coming into contact with moisture, thus ensuring rust prevention against moisture.

[0029] In addition, the present invention may also be characterized in that, in the above-mentioned toothed belt, the spacing between the belt teeth is 14 mm or more, and the height of the belt teeth is 5 mm or more.

[0030] Based on the above structure, when the tooth pitch (tooth spacing) is specified as an indicator of the toothed belt's size in specifications, increasing the tooth pitch (i.e., the number of teeth) ensures load-bearing capacity, meshing between the toothed belt and the toothed pulley, and shear force of the teeth, suitable for applications requiring high-tension power transmission performance under high-load (high-torque) environments. Therefore, in toothed belts, which fall into a relatively large category, durability, wear resistance, power transmission performance, and rust prevention can be ensured.

[0031] Additionally, the present invention may also be characterized in that the toothed belt is wound between a plurality of toothed pulleys having a plurality of pulley teeth formed on their outer periphery in a manner that engages with the belt teeth, such that the front end of the belt teeth contacts the bottom of the pulley teeth formed between the pulley teeth and the front end of the pulley teeth contacts the bottom of the belt teeth.

[0032] According to the above structure, the front end of the belt tooth contacts the bottom of the pulley tooth, and the front end of the pulley tooth contacts the bottom of the belt tooth, so that the load applied to the belt tooth (tooth load) is also distributed at the bottom of the belt tooth, thereby enabling meshing transmission in a way that is advantageous in terms of power transmission and belt tooth durability. Therefore, especially in toothed belts that require power transmission performance under high tension conditions corresponding to relatively high load (high torque) environments, such as large (high-capacity) wind turbines, it is possible to keep up with power transmission under high tension conditions and also ensure the wear resistance of the core wire.

[0033] In addition, the present invention can also be used in an environment where the tension applied to the toothed belt varies due to external factors, and is normally 0.30 kN / mm or more, and at most 0.80 to 1.10 kN / mm.

[0034] For example, like a toothed belt drive that adjusts the spacing between the blades of a wind turbine, even in strong winds, when the root of the wind turbine blades swings slightly, causing the teeth of the toothed belt to move back and forth slightly (reciprocating motion) due to the effect, or when a large tension is suddenly applied to the toothed belt (imagine the tension (load) applied to the toothed belt at this time), the toothed belt can be ensured to withstand such phenomena.

[0035] In addition, one aspect of the present invention is a toothed belt drive device, which comprises:

[0036] The aforementioned toothed band; and

[0037] Multiple toothed pulleys have multiple pulley teeth formed on their outer periphery in a manner that meshes with the teeth of the toothed belt.

[0038] The belt is wound between multiple toothed pulleys in such a way that the front end of the belt contacts the bottom of the pulley teeth formed between the pulley teeth and the front end of the pulley teeth contacts the bottom of the belt teeth, so as to perform meshing transmission.

[0039] In addition, the present invention may also be characterized in that, in the above-mentioned toothed belt drive device, the tension applied to the toothed belt varies due to external factors, and is normally 0.30 kN / mm or more, and is used in an environment where it is at most 0.80 to 1.10 kN / mm.

[0040] Invention Effects

[0041] According to the present invention, a toothed belt and a toothed belt drive device can be provided, which can adapt to the high-load environment (high-tension condition) of power transmission accompanying the large-scale (large-capacity power generation) of wind turbines in recent years, and can also adapt to the rust resistance accompanying marine installation (offshore wind power generation). Attached Figure Description

[0042] Figure 1 This is an explanatory diagram of a toothed belt drive device according to one embodiment of the present invention.

[0043] Figure 2 This refers to a portion of a toothed belt drive device according to one embodiment of the present invention, along the belt length direction (from... Figure 3 The side view (observed from the direction of the arrow I).

[0044] Figure 3 This is a cross-sectional view along the width direction of the toothed belt according to one embodiment of the present invention.

[0045] Figure 4 (a) is a cross-sectional view of the toothed belt along its length. Figure 4 (b) is a photograph of a cross-section of the toothed belt along its length. Figure 4 (c) is a photograph of a cross-section of the toothed belt along the width direction.

[0046] Figure 5 This is a schematic diagram illustrating a method for manufacturing a toothed belt according to one embodiment of the present invention.

[0047] Figure 6 This is a schematic diagram of the operational testing machine used in the operational test.

[0048] Figure 7 This is an explanatory diagram of the tooth profiles (G14M, G20M) of the toothed belt. Detailed Implementation

[0049] (Toothed belt drive device 1)

[0050] The toothed belt drive 1 of this invention is suitable for power transmission under high tension conditions corresponding to high load (high torque) environments. As an indicator of a high load environment, it is suitable for use in environments where the tension applied to the toothed belt 10 is constantly varying, typically above 0.30 kN / mm, with a maximum of 0.80 to 1.10 kN / mm. Another indicator is that it is suitable for use in environments where the torque applied to the toothed belt 10 is constantly varying, with a maximum of 15 kN·m to 45 kN·m.

[0051] For example, as an application of the toothed belt drive 1, a belt drive device can be used in wind turbines to adjust the blade angle under high-load conditions corresponding to the ever-changing wind direction and wind force (from ordinary wind to strong wind) generated in nature.

[0052] Specifically, such as Figure 1 As shown, the toothed belt drive device 1, used as a belt drive device, has a main structure consisting of a drive pulley 30, a toothed pulley 50 (driven pulley), an idler pulley 40, and a toothed belt 10 wound around them. Furthermore, the rotational power of the drive pulley 30 is transmitted to the toothed pulley 50, and the blade shaft, which is linked to the rotation of the toothed pulley 50, rotates to change the spacing (angle) of the wind turbine blades.

[0053] Furthermore, the toothed belt drive 1 is not limited to use as a belt drive in a wind turbine, but can be used in any drive that requires the same characteristics.

[0054] (10-tooth band)

[0055] Next, the toothed belt 10 according to the embodiments of the present invention will be described with reference to the accompanying drawings.

[0056] In this embodiment, the toothed belt 10 is an end-shaped meshing transmission belt, such as... Figures 2-4 As shown, it has a plurality of core wires 11, a back 12 in which a plurality of core wires 11 are embedded along the length of the belt, a plurality of belt teeth 13 formed on the inner circumference side of the back 12 along the length of the belt, and a plurality of belt tooth bottoms 14 formed between the belt teeth 13.

[0057] Multiple teeth 13 are opposite to the back 12 in the thickness direction (height direction of the teeth 13) and are arranged separately from each other in the length direction of the belt.

[0058] The teeth 13 and the tooth bottoms 14 are formed alternately in the length direction of the belt. The tooth bottoms 14 are the bottoms of the recesses formed between two adjacent teeth 13 in the length direction of the belt.

[0059] A cover layer 121 is provided between the toothed bottom 14 and the core wire 11 (on the inner circumference side of the core wire 11) to prevent the multiple core wires 11 from being exposed on the surface of the toothed bottom 14. The back 12, the multiple teeth 13, and the cover layer 121 are integrally formed of a thermoplastic elastomer. The thickness T (height in the thickness direction of the belt) of the cover layer 121 is 0.2 to 1.0 mm, and is particularly preferably about 0.3 to 0.6 mm.

[0060] Furthermore, the toothed band 10 is not limited to Figures 2-4The manner or structure shown. For example, multiple teeth 13 can mesh with the pulley teeth 53 of the toothed pulley 50. The cross-sectional shape of the teeth 13 (the cross-sectional shape of the toothed belt 10 in the belt length direction) is not limited to trapezoidal, and can also be semi-circular, semi-elliptical, polygonal (triangle, quadrilateral (rectangle, etc.) etc.).

[0061] Furthermore, the spacing (tooth pitch P13) between adjacent teeth 13 in the belt length direction is preferably 14 to 25 mm, for example. The value of the tooth pitch P13 also corresponds to the size of the teeth 13 (the length of the teeth 13 in the belt length direction and the tooth height of the teeth 13). That is, the larger the tooth pitch P13, the larger the size of the teeth 13 is. Especially in applications where high loads are applied, larger teeth 13 are required, and the tooth pitch P13 can be 14 mm or more, more preferably 20 mm or more. In addition, generally, Figure 2 The interval (distance) between adjacent teeth 13 on the pitch line (PL) shown is called the tooth pitch P13. Additionally, the distance from the bottom 14 of the tooth to PL is called PLD (Pitch Line Differential). Furthermore, the width of the tooth 13 in the length direction at the center position O in the thickness direction (height direction) of the tooth 13 is defined as the width of the tooth 13 (W13) (see reference). Figure 2 ).

[0062] In this embodiment, the toothed belt 10 satisfies the following requirements.

[0063] • Width W = 20-300mm;

[0064] • Total thickness H = 9–16 mm;

[0065] • The thickness of the back 12, H12, is 4mm or more;

[0066] • The thickness T of the covering layer 121 is 0.2–1.0 mm;

[0067] • The height H13 of each tooth 13 is 5-12 mm;

[0068] • The pitch P13 (distance on the pitch line PL) of tooth 13 is 14-25 mm;

[0069] • The belt strength per 1mm of belt width is 1kN or more (preferably 2.0kN or more and 5.0kN or less).

[0070] In specifications where the tooth pitch P13 is defined as an indicator of the size of the toothed belt 10, increasing the tooth pitch P13 (i.e., the number of teeth 13) ensures load-bearing capacity, meshing between the toothed belt 10 and the toothed pulley 50, and shear force of the teeth 13 for applications requiring high-tension power transmission performance under high-load (high-torque) environments. Therefore, even in a relatively large component like the toothed belt 10, durability, wear resistance, power transmission performance, and rust prevention can be ensured.

[0071] (Core 11)

[0072] Each core wire 11 is composed of steel cord (a cord formed by twisting steel cords). The steel cord is not limited to cords made solely of steel fibers; for example, it can be a twisted cord composed of other fibers such as aramid fibers and carbon fibers. Multiple core wires 11 extend separately along the length of the belt and are arranged along the width of the belt. Furthermore, in... Figure 2 In this context, the center position of the core wire 11 in the thickness direction is recorded as the pitch line PL. The pitch line PL refers to the reference line in the length direction of the toothed belt 10, which does not stretch or contract in the length direction even when the toothed belt 10 bends along the outer periphery of the toothed pulley 50.

[0073] (Regarding the density of the core wire arrangement)

[0074] Each core wire 11 is buried side-by-side on the back 12, spaced apart at a predetermined interval d along the length of the tape and in the width direction. That is, as shown... Figure 3 As shown, the core wires 11 are arranged on the back 12 at predetermined intervals d along the width direction. More specifically, the core wires 11 are preferably embedded in the back 12 such that the total value of the intervals d between adjacent core wires 11 in the width direction is a percentage (%) of 13% or more and 50% or less relative to the width W. Furthermore, the total value of the intervals d between adjacent core wires 11 in the width direction also includes the interval between the ends of the toothed belt 10 and the core wires 11 (both ends). That is, the total value of the intervals d between adjacent core wires 11 in the width direction is obtained by subtracting the value of the total core wire diameters D (core wire diameter D × number of core wires) from the value of the "width W". Therefore, the percentage (%) of the total value of the intervals d between adjacent core wires 11 in the width direction (the intervals d between core wires 11) relative to the width W is a value calculated using the following "Mathematical Formula 1".

[0075] [Mathematical Expression 1]

[0076]

[0077] The smaller the percentage (%) of the total interval d between adjacent core wires 11 in the width direction relative to the width W, the smaller the interval d between core wires 11, which means the density of the core wire arrangement is greater (closer). The greater the density of the core wire arrangement (closer), the more core wires are arranged per unit width of the belt, and therefore the greater the strength of the belt.

[0078] In this embodiment, the core wire 11 and the density of the core wire arrangement satisfy the following requirements.

[0079] • The diameter D of each core wire 11 is 1.5 mm or more (preferably 2.3 to 7.0 mm);

[0080] • The strength of each core wire 11 is 2.0kN or more (preferably 7.0 to 40kN);

[0081] • The spacing P11 of the core wires 11 is 1.8 mm or more (preferably 2.8 to 8.5 mm);

[0082] • The spacing d between the core wires 11 is 0.2 to 3.0 mm (preferably 0.3 to 1.7 mm);

[0083] The total value of the spacing d between the core wires 11 is a ratio of 13 to 50% (preferably 13 to 31%) to the band width W;

[0084] • The distance PLD from the bottom 14 of the toothed belt to PL is 1.35 to 4.50 mm.

[0085] Here, in addition to belt strength, the meshing properties of the toothed belt 10 and the toothed pulley 50, as well as the shear force of the teeth 13, become important as conditions for meeting the load-bearing requirements of the toothed belt. Specifically, if the teeth 13 are small, tooth skipping (tooth jumping) occurs; if the shear force of the teeth 13 is small, early tooth loss occurs, sometimes hindering operation (forward and backward motion). Such phenomena are greatly influenced by the choice of the dimensions of the teeth 13, therefore, the balance between belt strength and the dimensions of the teeth 13 becomes important. Therefore, considering the aforementioned balance, by setting the appropriate relationship (numerical value) between the dimensions of the teeth 13 and the core wire 11 as described above, the load-bearing capacity can be met in applications requiring power transmission performance under high tension conditions corresponding to relatively high load environments.

[0086] (Back 12, Toothed 13 and Covering 121)

[0087] The back 12, the plurality of teeth 13, and the cover layer 121 are integrally formed of a thermoplastic elastomer. The thermoplastic elastomer constituting the back 12, the plurality of teeth 13, and the cover layer 121 can be, for example, a polyurethane-based thermoplastic elastomer, a polyester-based thermoplastic elastomer, a polystyrene-based thermoplastic elastomer, a polyolefin-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer, a vinyl chloride-based thermoplastic elastomer, etc., or a combination of two or more of these thermoplastic elastomers. Polyurethane-based thermoplastic elastomers are particularly preferred. The type of polyurethane constituting the polyurethane-based thermoplastic elastomer can be a polyether-type polyurethane, a polyester-type polyurethane, or a polycarbonate-type polyurethane. The hardness of the thermoplastic elastomer can be 30–70° (measured using a type D hardness tester according to JIS K6253:2012), preferably 40–70°, and more preferably 50–60°.

[0088] (toothed pulley 50)

[0089] like Figure 1 and Figure 2 As shown, the toothed pulley 50 has a plurality of pulley teeth 53 disposed on its outer periphery in a manner that engages with the belt teeth 13 of the toothed belt 10, and a plurality of pulley tooth bottoms 54 formed between two adjacent pulley teeth 53.

[0090] The pulley teeth 53 and the pulley tooth bottoms 54 are formed alternately along the length of the wound toothed belt 10. The pulley tooth bottom 54 is the bottom of a recess formed between two adjacent pulley teeth 53 in the length direction of the belt.

[0091] In the toothed pulley 50, a belt tooth 13 is embedded in a recess formed between two adjacent pulley teeth 53. Additionally, a belt tooth 53 is embedded in a recess formed between two adjacent belt teeth 13 in the belt length direction. Furthermore, when the toothed pulley 50 meshes with the toothed belt 10, the front end of the belt tooth 13 contacts the bottom 54 of the belt tooth, and the front end of the belt tooth 53 contacts the bottom 14 of the belt tooth.

[0092] In this way, the front end of the belt tooth 13 contacts the bottom 54 of the pulley tooth, and the front end of the pulley tooth 53 contacts the bottom 14 of the belt tooth, so that the load applied to the belt tooth 13 (tooth load) is also distributed to the bottom 14 of the belt tooth, thereby enabling meshing transmission in a way that is advantageous in terms of power transmission and the durability of the belt tooth 13. Thus, especially in toothed belts 10 that require power transmission performance under high tension conditions corresponding to relatively high load (high torque) environments, such as large (high capacity) wind turbines, it is possible to follow the power transmission under high tension conditions and also ensure the wear resistance of the core wire 11.

[0093] According to the toothed belt 10 and toothed belt drive device 1 with the above structure, by providing a covering layer 121 with a thickness of 0.2 to 1.0 mm between the bottom of the belt teeth 14 and the core wire 11 (on the inner circumference side of the core wire 11), the core wire 11, which is composed of twisted cord containing steel fibers, is not located on the surface of the bottom of the belt teeth 14 (the core wire 11 is not directly exposed, and its position is isolated from the bottom of the belt teeth 14). Therefore, when meshing with the toothed pulley 50, even if the bottom of the belt teeth 14 contacts the front end of the pulley teeth 53, wear and breakage of the core wire 11 can be suppressed. In particular, for small-amplitude forward and backward movements (based on reciprocating motion of forward and reverse rotation), the covering layer 121 can protect the core wire 11 from wear and breakage.

[0094] In addition, since the core wire 11 is embedded in the thermoplastic elastomer, there is no part of the core wire 11 that contacts or is exposed to the surface of the toothed bottom 14, which prevents the core wire 11 (the twisted cord containing steel fibers) from contacting moisture, thus ensuring rust prevention against moisture.

[0095] Furthermore, when the toothed belt drive 1 is used in a high-load environment (where the tension applied to the toothed belt 10 varies due to external factors) corresponding to constantly changing wind direction and force (from ordinary wind to strong wind) in a wind turbine, for adjusting the blade angle, it is suitable for use in environments where the tension applied to the toothed belt 10 is constantly varying, typically above 0.30 kN / mm, with a maximum of 0.80 to 1.10 kN / mm. In another specification, it is suitable for use in environments where the torque applied to the toothed belt 10 is constantly varying, with a maximum of 15 kN·m to 45 kN·m. In such an environment, even in strong winds, when the root of the wind turbine blades swings slightly, causing the teeth 13 of the toothed belt 10 to move back and forth (reciprocating motion) with the toothed pulley 50, or when a large tension is suddenly applied to the toothed belt 10, a toothed belt 10 and toothed belt drive device 1 can be provided that can withstand such phenomena.

[0096] (Manufacturing method of toothed belt)

[0097] Next, an example of the manufacturing method of the toothed belt 10 will be described.

[0098] Toothed belt 10, for example, is made of Figure 5The manufacturing apparatus 60 shown is used for manufacturing. The manufacturing apparatus 60 includes: a forming roller 61; pulleys 62 and 63 arranged close to the forming roller 61 vertically; a pulley 64 arranged opposite the forming roller 61 in the horizontal direction; a pressing belt 65 wound around the pulleys 62 to 64 as annular metal strips; an extrusion head 66 for extruding thermoplastic elastomer; a core wire supply device (not shown); and a sheet supply device for the cover layer (not shown).

[0099] Grooves for forming teeth 13 are formed at predetermined intervals along the circumferential direction on the outer peripheral surface of the forming roller 61. The pulley 64 is movable horizontally relative to the forming roller 61, applying a predetermined tension to the pressing belt 65. The pressing belt 65 is configured to be wound around the outer peripheral surface of the forming roller 61 about half a turn, and is pressed against the outer peripheral surface of the forming roller 61 by the tension imparted from the pulley 64.

[0100] A sheet material feeder (not shown) supplies a sheet 15 of thermoplastic elastomer, pre-formed into a sheet shape, to the outer peripheral surface of a forming roller 61. A core wire feeder (not shown) supplies a plurality of core wires 11 arranged axially along the forming roller 61 to the outer peripheral surface of the sheet 15 supplied to the outer peripheral surface of the forming roller 61. An extrusion head 66 supplies molten thermoplastic elastomer, heated to the outer peripheral surface of the sheet 15 and the core wires 11 supplied to the outer peripheral surface of the forming roller 61.

[0101] Molten thermoplastic elastomer, multiple core wires 11, and a cover sheet 15 supplied to the outer peripheral surface of the molding roller 61 are wound between the molding roller 61 and the pressing belt 65 as the molding roller 61 rotates. At this time, the thermoplastic elastomer is filled into a groove formed on the outer peripheral surface of the molding roller 61 by the pressing force of the pressing belt 65, forming a toothed band 13 in the groove. Meanwhile, the supplied cover sheet 15 is positioned between the outer peripheral surface of the molding roller 61 and the multiple core wires 11 at the portion forming the bottom 14 of the toothed band, and is mixed with the supplied molten thermoplastic elastomer at other portions. Furthermore, a back surface 12 in which the multiple core wires 11 are embedded is formed between the cover sheet 15 disposed on the outer peripheral surface of the molding roller 61 and the pressing belt 65. Then, the thermoplastic elastomer is forcefully pressed against the outer peripheral surface of the molding roller 61 by the pressing force of the pressing belt 65, and the thermoplastic elastomer is cooled and solidified. In the portion of the pressing belt 65 away from the forming roller 61, the toothed belt 10 is continuously removed. In the series of forming processes described above, in which the thermoplastic material cools and solidifies from the molten state, the cover sheet 15 (thermoplastic elastomer) is integrated with the thermoplastic elastomer forming the toothed belt 13 and the back 12 supplied in the molten state.

[0102] Example

[0103] Using the manufacturing method described above and employing thermoplastic elastomers, toothed belts as described in Examples 1-41, Comparative Examples 1-14, and Reference Examples 1-6 were manufactured. The rust resistance of these toothed belts and their operational performance in toothed belt drive devices were verified. The structures and verification results of each toothed belt drive device described in Examples 1-41, Comparative Examples 1-14, and Reference Examples 1-6 are shown in Tables 1-11.

[0104] [Table 1]

[0105]

[0106] [Table 2]

[0107]

[0108] [Table 3]

[0109]

[0110] [Table 4]

[0111]

[0112] [Table 5]

[0113]

[0114] [Table 6]

[0115] Table 6

[0116]

[0117] [Table 7]

[0118] Table 7

[0119]

[0120] [Table 8]

[0121] Table 8

[0122]

[0123] [Table 9]

[0124] Table 9

[0125]

[0126] [Table 10]

[0127] Table 10

[0128]

[0129] [Table 11]

[0130] Table 11

[0131]

[0132] [Materials used]

[0133] Thermoplastic elastomer 1: Polyester-type polyurethane thermoplastic elastomer [Covestro Desmopan 3055DU]

[0134] Thermoplastic elastomer 2: Polyether-type polyurethane thermoplastic elastomer [Covestro Desmopan 9852DU]

[0135] Thermoplastic elastomer 3: Polyamide-based thermoplastic elastomer [TPAE-617C manufactured by T&K TOKA Co., Ltd.]

[0136] Core 1: Steel cord, 84 strands, 2.5mm diameter, 7.2kN strength.

[0137] Core 2: Steel cord, 84 strands, 3.3mm diameter, 11kN strength

[0138] Core 3: Steel cord, 133 strands, 4.3mm diameter, 22kN strength

[0139] Core 4: Steel cord, 133 strands, 6.4mm diameter, 36kN strength

[0140] Core 5: Steel cord, 49 strands, 1.6mm diameter, 3.0kN strength.

[0141] [Verification Method]

[0142] (Strength of the toothed band)

[0143] Test pieces were collected from the toothed belts involved in Examples 1-41, Comparative Examples 1-14, and Reference Examples 1-6. For each test piece, a tensile test was performed using an Amsler tensile testing machine (tensile speed 50 mm / min). The breaking strength of the toothed belt was measured, and the breaking strength per unit width was calculated as the belt strength (kN / mm). The dimensions of the test pieces were 20 mm wide and 500 mm long in Examples 1-13, 40, 41, Comparative Examples 1-8, and Reference Examples 1, 2, and 6; and 25 mm wide and 500 mm long in Examples 14-38, Comparative Examples 9-14, and Reference Examples 3-5. In Example 39, the dimensions were set to 35 mm wide and 500 mm long.

[0144] (Rust prevention)

[0145] To confirm the rust-preventive properties of the toothed strips involved in Examples 1-41, Comparative Examples 1-14, and Reference Examples 1-6, a salt spray test was conducted. It should be noted that the toothed strips in Comparative Examples 1-4 are identical; therefore, the toothed strip of Comparative Example 4 was used as the representative test subject. Similarly, in Comparative Examples 5-8, the toothed strip of Comparative Example 8 was used as the representative test subject; in Comparative Examples 9-11, the toothed strip of Comparative Example 11 was used as the representative test subject; and in Comparative Examples 12-14, the toothed strip of Comparative Example 14 was used as the representative test subject.

[0146] From the toothed belts manufactured in Examples 1-41, Comparative Examples 4, 8, 11, 14, and Reference Examples 1-6, test pieces for appearance confirmation and belt strength determination were collected. For each test piece, a salt spray test was conducted according to the neutral salt damage test method specified in ISO 9227-2012 to confirm the appearance (rust formation) after 720 hours. Then, the belt strength (breaking strength) after 720 hours was measured, and the rate of strength reduction relative to the belt strength before the test was calculated (refer to the items "Belt Strength" and "Strength Reduction Rate" in Tables 1-11).

[0147] In addition, in the evaluation of "rust resistance" in Tables 1 to 11, "◎" indicates that no rust was formed, "○" indicates that rust was formed to a degree that does not affect the service life (strength reduction rate of less than 5%), and "×" indicates that rust was formed significantly to a degree that renders the product unusable (strength reduction rate of more than 5%).

[0148] In addition, the salt spray test was conducted using a 5% NaCl solution (pH 6.5–7.2) at a temperature of 35 ± 2°C. Furthermore, the dimensions of the test pieces used for appearance confirmation were 20 mm wide and 50 mm long in Examples 1–13, 40, 41, Comparative Examples 1–8, and Reference Examples 1, 2, 6; 25 mm wide and 50 mm long in Examples 14–38, Comparative Examples 9–14, and Reference Examples 3–5; and 35 mm wide and 50 mm long in Example 39.

[0149] Furthermore, the dimensions of the test piece used for strength testing were 20 mm wide and 750 mm long in Examples 1-13, 40, 41, Comparative Examples 1-8, and Reference Examples 1, 2, and 6; 25 mm wide and 750 mm long in Examples 14-38, Comparative Examples 9-14, and Reference Examples 3-5; and 35 mm wide and 750 mm long in Example 39.

[0150] (Operating performance)

[0151] Ten samples were collected from each toothed belt involved in Examples 1-41, Comparative Examples 4, 8, 11, 14, and Reference Examples 1-6, as follows: Figure 6 As shown, weights 71 and 72 are suspended at both ends of the test piece 10x, respectively, and are wound around the drive pulley 73, driven pulley 74, and flat pulley 75 (diameter = 160 mm) of the operating testing machine 70. Then, it is subjected to 1.2 million cycles at a specified travel distance. Figure 6 The test was repeated (one reciprocation in the direction of the arrows represents one cycle), and the condition of the toothed belt and its bottom was evaluated after the test (refer to the "Degree of the Toothed Belt" and "Degree of the Toothed Belt" items in Tables 1-11). In the evaluation of the "Degree of the Toothed Belt" and "Degree of the Toothed Belt" in Tables 1-11, "◎" indicates no wear, "○" indicates wear to a degree that does not affect the usable durability, and "×" indicates significant wear to a degree that renders the belt unusable.

[0152] In addition, the belt strength (breaking strength) after the operation test is measured, and the rate of strength reduction relative to the belt strength before the operation test is calculated (refer to the items "Belt Strength (after operation)" and "Strength Reduction Rate" in Tables 1 to 11).

[0153] Furthermore, if the belt reaches a state of inoperability before reaching 1.2 million cycles, it is judged as having reached its service life, and the operation test is terminated (refer to the "Belt Failure" items in Tables 1 to 11).

[0154] The above operational tests varied the tension applied to each toothed belt at three levels (7.0 kN, 8.0 kN, and 11.2 kN) to compare the durability of each toothed belt under conditions ranging from low to high tension. The tension levels are shown in Table 12 below, with the loads of counterweights 71 and 72 set by varying the values. Furthermore, at each level, the number of teeth on the drive pulley 73 and the driven pulley 74, as well as the travel distance per cycle, were varied.

[0155] [Table 12]

[0156] Table 12

[0157]

[0158] Based on the results of the operational tests, the toothed belts involved in Examples 1-41, Comparative Examples 4, 8, 11, 14, and Reference Examples 1-6 were classified into grades A to D according to the criteria shown in Table 13 below, and recorded in the "Judgment" items of Tables 1-11. Furthermore, among grades A to D, toothed belts of grades A and B, which can complete 1.2 million cycles without significant failure, are products that can be practically used at an excellent level. However, toothed belts of grade C, which can operate for more than 1 million cycles, are also positioned as practically usable products (acceptable level) depending on the usage conditions.

[0159] [Table 13]

[0160] Table 13

[0161]

[0162] [Verification Result]

[0163] <Comparison and Verification in Table 1>

[0164] In Table 1, for the toothed belt with the same dimensions as described in Patent Document 4 (tooth spacing 14mm, belt width 20mm: tooth type G14M, refer to...) Figure 7 Furthermore, toothed belts using the same core wire 1 (diameter D = 2.5 mm, strength 7.2 kN) were used. For comparison: (A) a toothed belt drive device with a gap S between the front end of the pulley tooth and the bottom of the tooth, where the core wire is located at the position of contact with the surface (or reinforcing cloth) of the tooth bottom; (B) a toothed belt drive device with a covering layer on the inner circumference side of the core wire, where the gap S is not provided and the bottom of the tooth contacts the pulley tooth; and (C) a toothed belt drive device with a gap S not provided and the bottom of the tooth contacts the pulley tooth in the toothed belt of (A) above. The structures of the toothed belts of Examples 1 to 3 and Comparative Examples 1 to 8 are described.

[0165] (Examples 1-3)

[0166] The toothed belt drive devices in Examples 1-3 are toothed belts with a covering layer on the inner circumference of the core wire described in (B) above. No gap S is provided, and the bottom of the belt teeth contacts the pulley teeth. The thickness of the covering layer is varied as 0.2 mm (Example 1), 0.5 mm (Example 2), and 0.8 mm (Example 3). No rust forms on the core wire in any of the toothed belts during the salt spray test, and the reduction in belt strength is minimal, demonstrating excellent rust resistance. Regarding operational performance, in Examples 1 and 3, the performance is Grade B under low tension (7.0 kN, 8.0 kN) conditions, but Grade C under high tension (11.2 kN) conditions. In contrast, in Example 2, the performance is Grade A under low tension (7.0 kN) conditions and Grade B under high tension (8.0 kN, 11.2 kN) conditions.

[0167] That is, toothed belts with a cover layer thickness of 0.5 mm are practical even under the highest tension condition (11.2 kN), but toothed belts with a cover layer thickness of 0.2 mm or 0.8 mm are practical under a high tension condition of around 8 kN, but not under the highest tension condition (11.2 kN). Based on this result, it can be said that the thickness of the cover layer is preferably around 0.5 mm (around 0.4 to 0.6 mm). Especially under high tension conditions, if the cover layer thickness is small, the core wire will be exposed at the bottom of the belt teeth during operation due to wear of the cover layer, and the wear of the core wire will easily lead to breakage. On the other hand, if the cover layer thickness is large, the belt teeth will easily bear the stress (tooth load) applied to the toothed belt, which can easily lead to failures caused by missing teeth.

[0168] The toothed belt drive devices of Examples 1 to 3 can adapt to power transmission under high tension conditions, which is beneficial to power transmission performance and tooth durability.

[0169] (Comparative Examples 1-4)

[0170] Comparative Examples 1-4 are toothed belts that lack a covering layer on the inner circumference of the core wire (steel cord) and have the inner circumferential surface, including the bottom of the teeth, covered by reinforcing fabric. In these toothed belts, the core wire is located in contact with the bottom surface of the teeth (reinforcing fabric). In salt spray tests, rust formed on the core wire, and a decrease in belt strength was observed, resulting in a lack of rust protection. In these toothed belts, although the core wire is not exposed on the bottom surface of the teeth due to the reinforcing fabric, rust formed on the core wire (steel cord) due to contact with the moisture-absorbing reinforcing fabric. This type of toothed belt is detrimental to the rust protection of the core wire against salt water (moisture).

[0171] Furthermore, the toothed belt drive devices of Comparative Examples 1 to 3 are equivalent to Embodiments 1, 3, and 6 of Patent Document 4. They use a toothed belt with the core wire of (A) located at the position of contact with the bottom surface of the teeth (reinforcing fabric), and the gap S between the front end of the pulley teeth and the bottom of the belt teeth is set to vary from 0.25 mm (Comparative Example 1), 0.5 mm (Comparative Example 2), and 0.8 mm (Comparative Example 3). Regarding operating performance, all were rated A or B under low tension (7.0 kN) conditions, but in Comparative Example 3, with a larger gap S under tension of 8.0 kN, it was rated C. Under the highest tension (11.2 kN) conditions, all experienced early failure (missing teeth) and were rated D.

[0172] In other words, the method of setting a gap S between the front end of the pulley tooth and the bottom of the tooth is practical under low tension conditions (around 7.0 kN). However, if the gap S is large, it is not practical under high tension conditions (8.0 kN), and under the highest tension conditions (11.2 kN), it is not practical regardless of the size of the gap S. According to this result, in the method of setting a gap S between the front end of the pulley tooth and the bottom of the tooth, the bottom of the tooth does not contact the pulley tooth when meshing. Therefore, the tooth bears the concentrated stress applied to the toothed belt (when the bottom of the tooth contacts the pulley tooth, the stress is distributed between the tooth and the bottom of the tooth). Therefore, especially under high tension conditions, the stress on the tooth becomes particularly large, leading to early failures caused by missing teeth. In this method where the bottom of the tooth does not contact the pulley tooth (tooth-top drive method), it is impossible to keep up with power transmission under high tension conditions, which can be considered detrimental to power transmission performance and tooth durability.

[0173] Furthermore, the toothed belt drive device of Comparative Example 4 is equivalent to Comparative Example 1 of Patent Document 4. It uses a toothed belt with the core wire of the above-mentioned (C) positioned in contact with the bottom surface of the teeth (reinforcing cloth), and does not have a gap S between the front end of the pulley teeth and the bottom of the teeth (the bottom of the teeth contacts the pulley teeth). Regarding operating performance, even under low tension (7.0 kN) conditions, it becomes a grade C due to wear at the bottom of the teeth, and under further high tension conditions, it becomes a grade D due to early failure (core wire breakage). In this method, there is no covering layer on the inner circumference of the core wire; only reinforcing cloth is provided. Moreover, the bottom of the teeth contacts the pulley teeth. Therefore, due to wear of the reinforcing cloth, the core wire is exposed at the bottom of the teeth during operation, and the wear of the core wire develops, leading to core wire breakage.

[0174] (Comparative Examples 5-8)

[0175] Comparative Examples 5-8, with their toothed tapes, exhibited a design where the inner circumference of the core wire (steel cord) lacked a covering layer or reinforcing fabric, and the core wire was positioned in contact with the bottom surface of the teeth. In salt spray tests, rust formed on the core wire, and a decrease in tape strength was observed, indicating a lack of rust protection. In these toothed tapes, a portion of the core wire was in contact with the bottom surface of the teeth, leading to rust formation on the core wire (steel cord) due to moisture adhering to the bottom surface of the teeth. This type of toothed tape is detrimental to the rust protection of the core wire against salt water (moisture).

[0176] Furthermore, the toothed belt drive devices of Comparative Examples 5 to 7 are equivalent to Embodiments 20 to 22 of Patent Document 4. They use a toothed belt with the core wire of (A) located at the position in contact with the bottom surface of the teeth, and the gap S between the front end of the pulley teeth and the bottom of the belt teeth is set to vary from 0.25 mm (Comparative Example 5), 0.5 mm (Comparative Example 6), and 0.8 mm (Comparative Example 7). Regarding operating performance, all are rated A or B under low tension (7.0 kN) conditions, but in Comparative Example 7, with a larger gap S under tension of 8.0 kN, it is rated C. Under the highest tension (11.2 kN) conditions, all are rated D due to early failure (missing teeth).

[0177] Based on these results, as mentioned above, the method of setting the gap S between the front end of the pulley tooth and the bottom of the belt tooth is practical under low tension conditions (around 7.0 kN). However, if the gap S is large, it is not practical under high tension conditions of 8.0 kN, and under the highest tension conditions (11.2 kN), it is not practical regardless of the size of the gap S. In this method where the bottom of the belt tooth does not contact the pulley tooth (tooth tip transmission method), it is impossible to follow the power transmission under high tension conditions, which can be said to be a method that is detrimental to power transmission performance and belt tooth durability.

[0178] Furthermore, the toothed belt drive device of Comparative Example 8 is equivalent to Comparative Example 2 of Patent Document 4. It uses a toothed belt with the core wire of the above-mentioned (C) positioned in contact with the bottom surface of the teeth, and does not provide a gap S between the front end of the pulley teeth and the bottom of the belt teeth (where the bottom of the belt teeth contacts the pulley teeth). Regarding operating performance, even under low tension (7.0 kN) conditions, it becomes a grade C due to wear at the bottom of the belt teeth, and under further high tension conditions, it becomes a grade D due to early failure (core wire breakage). In this method, there is neither a covering layer nor a reinforcing fabric on the inner circumference of the core wire, and the bottom of the belt teeth contacts the pulley teeth. Therefore, during operation, wear of the core wire exposed at the bottom of the belt teeth develops, leading to core wire breakage.

[0179] <Comparison and Verification in Table 2>

[0180] In Table 2, to compare the toothed belts of Example 2 (core wire spacing of 3.2 mm, number of core wires of 6, belt strength of 2.18 kN / mm) with variations in core wire spacing of 2.5 mm (Reference Example 1), 2.8 mm (Example 5), and 4.0 mm (Example 4), the structures of the toothed belts of Examples 2, 4, 5, and Reference Example 1 are described. Additionally, Table 2 also describes the structures of toothed belts of Examples 6 and 7, which have the same belt strength (core wire structure and arrangement density) as Example 2 but with larger tooth dimensions. Furthermore, Table 2 also describes the structure of a toothed belt of Reference Example 2, which has the same belt strength (core wire structure and arrangement density) as Example 2 but with smaller tooth dimensions.

[0181] (Examples 4, 5 and Reference Example 1)

[0182] In Example 5, which reduces the core wire spacing and increases the number of core wires to 7 (increasing the density of the core wire arrangement) compared to Example 2, the tape strength is increased (2.53 kN / mm).

[0183] On the other hand, in Example 4, which increases the core wire spacing and reduces the number of core wires to 5 (reducing the density of the core wire arrangement) compared to Example 2, the tape strength is reduced (the tape strength is 1.18 kN / mm).

[0184] In Examples 4 and 5, the toothed belts did not exhibit rust formation in the core wire during salt spray testing, and the reduction in belt strength was minimal, demonstrating excellent rust resistance. Regarding operational performance, in Example 5, it achieved Grade A under low tension (7.0 kN) conditions, as in Example 2, and Grade B under high tension (8.0 kN, 11.2 kN) conditions. In Example 4, it achieved Grade B under low tension (7.0 kN, 8.0 kN) conditions, but under high tension (11.2 kN) conditions, core wire breakage occurred before reaching 1.2 million cycles (1 million cycles), resulting in Grade C. Each example represents a practical level depending on the usage conditions.

[0185] In Reference Example 1, where the core wire spacing is reduced to the limit and the core wires are arranged without gaps, the belt strength is the highest (2.88 kN / mm), but the operating performance is classified as Grade D due to early failure (belt loop breakage) under all tension conditions. If the spacing d between adjacent core wires is 0, the thermoplastic elastomer does not flow between the core wires, and the core wires are not held in place by the thermoplastic elastomer. Therefore, breakage occurs between adjacent core wires due to belt operation, leading to belt loop breakage.

[0186] The results above confirm that it is practical for use within the range of 2.8–4.0 mm core wire spacing and 1.18–2.53 kN / mm tape strength per 1 mm tape width.

[0187] (Examples 6 and 7)

[0188] Examples 6 and 7 differ from the toothed belt with a tooth pitch of 14 mm (tooth type G14M) in Example 2 by changing the tooth size to a tooth pitch of 20 mm (tooth type G20M) and 25 mm (tooth type G25M).

[0189] In Examples 6 and 7, the toothed belts did not rust in the core wire during the salt spray test, and the reduction in belt strength was minimal, demonstrating excellent rust resistance. Regarding operational performance, they were rated A under low tension (7.0 kN) conditions and B under high tension (8.0 kN, 11.2 kN) conditions, similar to Example 2.

[0190] (See Example 2 for reference)

[0191] Referring to Example 2, compared to the toothed belt with a tooth pitch of 14 mm (tooth type G14M) in Example 2, the tooth size is changed to a tooth pitch of 8 mm (tooth type S8M). That is, it is an example with the same core wire arrangement and the same belt strength as in Example 2, but with smaller tooth size.

[0192] The toothed belt in Example 2 showed no rust formation on the core wire during the salt spray test, with minimal reduction in belt strength, demonstrating excellent rust resistance. However, regarding operational performance, it also suffered from early failure (missing teeth) under low tension (7.0 kN) conditions, resulting in a grade D (unusable) rating (unsuitable for practical use).

[0193] Therefore, it can be said that, in practical terms, the preferred tooth size is one with a tooth pitch of 14mm or more.

[0194] <Comparison and Verification in Table 3>

[0195] In Table 3, the structures of the toothed belts of Examples 2, 8, and 9 are described in order to compare the cases in which the thermoplastic elastomer was changed from polyester-type polyurethane to polyether-type polyurethane (Example 8) and polyamide-type (Example 9) in the toothed belt of Example 2.

[0196] In addition, in Table 3, the structures of the toothed belts of Examples 2, 10 to 13 are described in order to compare the hardness of the polyester-type polyurethane thermoplastic elastomer in the toothed belt of Example 2 when it changes from 50° to 30° (Example 10), 40° (Example 11), 60° (Example 12), and 70° (Example 13).

[0197] (Examples 8 and 9)

[0198] In Examples 8 and 9, where the polyester-type polyurethane thermoplastic elastomer in the toothed belt of Example 2 was changed to a polyether-type polyurethane elastomer, the belt strength was the same as in Example 2. The toothed belts of Examples 8 and 9 did not produce rust on the core wire during the salt spray test, and the reduction in belt strength was minimal, demonstrating excellent rust resistance. Regarding operational performance, they were also rated A under low tension (7.0 kN) conditions and B under high tension (8.0 kN, 11.2 kN) conditions, identical to Example 2.

[0199] (Examples 10-13)

[0200] In Examples 10 and 11, which reduced the hardness of the thermoplastic elastomer compared to Example 2, and Examples 12 and 13, which increased the hardness, the strip strength was the same as in Example 2. The toothed strips of Examples 10-13 did not rust in the core wire during salt spray testing, exhibited minimal reduction in strip strength, and demonstrated excellent rust resistance.

[0201] Regarding operational performance, in Example 12, where the hardness was increased, it achieved Grade A under low tension (7.0 kN) conditions and Grade B under high tension (8.0 kN, 11.2 kN) conditions, similar to Example 2. Furthermore, in Example 13, with high hardness, it achieved Grade B under conditions ranging from low tension (7.0 kN) to high tension (11.2 kN). On the other hand, in Example 11, where the hardness was decreased, it achieved Grade B under conditions ranging from low tension (7.0 kN) to high tension (11.2 kN). Moreover, in Example 10, with low hardness, it achieved Grade B under low tension (7.0 kN, 8.0 kN) conditions, but under high tension (11.2 kN) conditions, it developed tooth chipping after 1 million cycles, resulting in Grade C. Each example represents a level of practicality depending on the usage conditions.

[0202] <Comparison and Verification in Table 4>

[0203] In Table 4, a toothed belt with higher strength specifications compared to the toothed belt described in Patent Document 4 is listed as a toothed belt (tooth type G14M, see reference) with a tooth pitch of 14 mm, a belt width of 25 mm, and using core wire 2 (diameter D = 3.3 mm, strength 11 kN). Figure 7 The comparisons (A) to (C) above were performed, and the structures of the toothed belts of Examples 14 to 17 and Comparative Examples 9 to 11 were described.

[0204] (Examples 14-17)

[0205] The toothed belt drive devices of Examples 14-17 are toothed belts with a covering layer on the inner circumference of the core wire described in (B) above. No gap S is provided, and the bottom of the belt teeth contacts the pulley teeth. The thickness of the covering layer is varied to 0.2 mm (Example 14), 0.3 mm (Example 15), 0.5 mm (Example 16), and 0.8 mm (Example 17). No rust forms on the core wire in any of the toothed belts during the salt spray test, and the reduction in belt strength is minimal, demonstrating excellent rust resistance. Regarding operational performance, in Examples 14 and 17, the conditions from low tension (7.0 kN) to high tension (11.2 kN) are classified as Grade B. In contrast, in Examples 15 and 16, the conditions under low tension (7.0 kN, 8.0 kN) are Grade A, and the conditions under high tension (11.2 kN) are also Grade B.

[0206] That is, toothed belts with a cover layer thickness of 0.5 mm are not limited to those with a thickness of 0.2 mm or 0.8 mm; even those with a cover layer thickness of 0.2 mm or 0.8 mm can be used under the highest tension conditions (11.2 kN). It can be said that toothed belts with a cover layer thickness of approximately 0.3 to 0.5 mm (approximately 0.25 to 0.6 mm) are particularly preferred. The toothed belt drive devices of Examples 14 to 17 are capable of power transmission under high tension conditions, and are advantageous for power transmission performance and tooth durability.

[0207] (Comparative Examples 9-11)

[0208] Comparative Examples 9-11 have toothed belts where the inner circumference of the core wire (steel cord) lacks a covering layer and reinforcing fabric, and the core wire is positioned in contact with the bottom surface of the belt teeth. In salt spray tests, rust formed on the core wire, and a decrease in belt strength was observed, indicating a lack of rust prevention.

[0209] Furthermore, the toothed belt drive devices in Comparative Examples 9 and 10 used a toothed belt with the core wire of (A) in contact with the bottom surface of the teeth, and the gap S between the front end of the pulley teeth and the bottom of the belt teeth was set to 0.5 mm (Comparative Example 9) and 0.8 mm (Comparative Example 10), respectively. Regarding operating performance, all were rated B under low tension (7.0 kN) conditions, but in Comparative Example 10, with a large gap S under tension of 8.0 kN, it became rated C, and under the highest tension (11.2 kN) conditions, it became rated D due to early failure (missing teeth).

[0210] Furthermore, the toothed belt drive in Comparative Example 11 uses a toothed belt with the core wire of (C) in contact with the bottom surface of the teeth, and does not have a gap S between the front end of the pulley teeth and the bottom of the belt teeth (where the bottom of the belt teeth contacts the pulley teeth). Regarding operating performance, even under low tension (7.0 kN) conditions, it becomes a grade C due to wear at the bottom of the belt teeth, and under further high tension conditions, it becomes a grade D due to early failure (core wire breakage).

[0211] The results shown in Table 4 verify that even in toothed belts with higher strength specifications [tooth spacing 14 mm, belt width 25 mm, core wire 2 (diameter D = 3.3 mm, strength 11 kN)], the same tendency as that shown in Table 1 was observed. The method of the present invention can adapt to power transmission under high tension conditions and is a method that is beneficial to power transmission performance and tooth durability.

[0212] <Comparison and Verification in Table 5>

[0213] In Table 5, to compare the toothed belts of Example 16 (core wire spacing of 3.9 mm, number of core wires of 6, belt strength of 2.65 kN / mm) with variations in core wire spacing of 4.8 mm (Example 18) and 3.3 mm (Reference Example 3), the structures of the toothed belts of Examples 16, 18, and 3 are described. Additionally, Table 5 also describes the structures of toothed belts of Examples 19 and 20, which have the same belt strength (core wire structure and arrangement density) as Example 16 but with larger tooth dimensions. Furthermore, Table 5 also describes the structure of the toothed belt of Reference Example 4, which has the same belt strength (core wire structure and arrangement density) as Example 16 but with smaller tooth dimensions.

[0214] (Example 18 and Reference Example 3)

[0215] In Example 18, which increases the core spacing and reduces the number of cores to 5 (reducing the density of the core arrangement) compared to Example 16, the tape strength is reduced (tape strength 2.20 kN / mm).

[0216] The toothed belt of Example 18 did not rust in the core wire during the salt spray test, and the reduction in belt strength was minimal, demonstrating excellent rust resistance. Regarding operational performance, it was rated A under low tension (7.0 kN) conditions, but under high tension (8.0 kN, 11.2 kN) conditions, the core wire broke before reaching 1.2 million cycles (1-1.1 million cycles), resulting in a rating of C. The performance level is considered practical depending on the usage conditions.

[0217] In Reference Example 3, where the core wire spacing is reduced to the limit and the core wires are arranged without gaps, the belt strength is the highest (3.08 kN / mm), but the operating performance is classified as Grade D due to early failure (belt loop breakage) under all tension conditions. If the spacing d between adjacent core wires is 0, the thermoplastic elastomer does not flow between the core wires, and the core wires are not held in place by the thermoplastic elastomer. Therefore, due to belt operation, segments are created between adjacent core wires, leading to belt loop breakage.

[0218] The results above confirm that it is practical for use within the range of 3.9–4.8 mm core wire spacing and 2.20–2.65 kN / mm tape strength per 1 mm tape width.

[0219] (Examples 19 and 20)

[0220] Examples 19 and 20 differ from the toothed belt with a tooth pitch of 14 mm (tooth type G14M) in Example 16 by changing the tooth size to a tooth pitch of 20 mm (tooth type G20M) and 25 mm (tooth type G25M).

[0221] In the salt spray test, the toothed belts of Examples 19 and 20 showed no rust formation on the core wire, minimal reduction in belt strength, and excellent rust resistance. Regarding operational performance, they were rated A under low tension (7.0 kN, 8.0 kN) conditions and B under high tension (11.2 kN) conditions, similar to Example 16.

[0222] (Refer to Example 4)

[0223] Reference Example 4 is a toothed belt with a tooth pitch of 8 mm (tooth type S8M) compared to the toothed belt with a tooth pitch of 14 mm (tooth type G14M) in Example 16, while keeping the core wire structure and arrangement density the same. That is, it is an example with the same belt strength as Example 16, but with smaller tooth size.

[0224] The toothed belt in Example 4 did not rust on the core wire during the salt spray test, and the reduction in belt strength was minimal, demonstrating excellent rust resistance. However, regarding operational performance, it also suffered from early failure (missing teeth) under low tension (7.0 kN) conditions, resulting in a grade D (unusable) rating (unsuitable for practical use).

[0225] Therefore, it can be said that, in practical terms, the preferred tooth size is one with a tooth pitch of 14mm or more.

[0226] <Comparison and Verification in Table 6>

[0227] In Table 6, the structures of the toothed strips of Examples 16, 21, and 22 are described in order to compare the cases in which the thermoplastic elastomer was changed from polyester-type polyurethane to polyether-type polyurethane (Example 21) and polyamide-type (Example 22) in the toothed strip of Example 16.

[0228] In addition, in Table 6, the structure of the toothed belts of Examples 16, 23 to 26 is described in order to compare the cases in which the hardness of the polyester-type polyurethane thermoplastic elastomer was changed from 50° to 30° (Example 23), 40° (Example 24), 60° (Example 25), and 70° (Example 26).

[0229] (Examples 21 and 22)

[0230] In Examples 21 and 22, where the polyester-type polyurethane thermoplastic elastomer in the toothed belt of Example 16 was changed to a polyether-type polyurethane elastomer, the belt strength was the same as in Example 16. The toothed belts of Examples 21 and 22 did not produce rust on the core wire during salt spray testing, and the reduction in belt strength was minimal, demonstrating excellent rust resistance. Regarding operational performance, they were also rated A under low tension (7.0 kN, 8.0 kN) conditions and B under high tension (11.2 kN) conditions, identical to Example 16.

[0231] (Examples 23-26)

[0232] In Examples 23 and 24, which reduced the hardness of the thermoplastic elastomer compared to Example 16, and Examples 25 and 26, which increased the hardness, the strip strength was the same as in Example 16. The toothed strips of Examples 23-26 did not rust in the core wire during salt spray testing, exhibited minimal reduction in strip strength, and demonstrated excellent rust resistance.

[0233] Regarding operational performance, in Example 25, where the hardness was increased, it achieved Grade A under low tension (7.0 kN, 8.0 kN) and Grade B under high tension (11.2 kN), similar to Example 16. Furthermore, in Example 26, with high hardness, it achieved Grade A under low tension (7.0 kN) and Grade B under high tension (8.0 kN, 11.2 kN). On the other hand, in Example 24, where the hardness was decreased, it achieved Grade A under low tension (7.0 kN) and Grade B under high tension (8.0 kN, 11.2 kN). Moreover, in Example 23, with low hardness, it achieved Grade B under low tension (7.0 kN, 8.0 kN) but became Grade C after 1 million cycles under high tension (11.2 kN). Each example represents a level of practicality depending on the usage conditions.

[0234] <Comparison and Verification in Table 7>

[0235] Table 7 lists toothed belts with further high dimensions and high strength specifications. For example, a toothed belt (tooth type G20M, refer to Table 7) with a tooth pitch of 20mm, a belt width of 25mm, and using core wire 3 (diameter D = 4.3mm, strength 22kN) is provided. Figure 7 The comparisons (A) to (C) above were performed, and the structures of the toothed belts of Examples 27 to 29 and Comparative Examples 12 to 14 were described.

[0236] (Examples 27-29)

[0237] The toothed belt drive devices of Examples 27-29 are toothed belts with a covering layer on the inner circumference of the core wire described in (B) above. The belt teeth are in contact with the pulley teeth without a gap S. The thickness of the covering layer is varied, being 0.2 mm (Example 27), 0.5 mm (Example 28), and 1.0 mm (Example 29). No rust forms on the core wire in any of the toothed belts during the salt spray test, and the reduction in belt strength is minimal, demonstrating excellent rust resistance. Regarding operational performance, in Examples 27 and 29, the conditions from low tension (7.0 kN) to high tension (11.2 kN) are classified as Grade B. In contrast, in Example 28, the conditions from low tension (7.0 kN) to high tension (11.2 kN) are classified as Grade A.

[0238] That is, toothed belts with a cover layer thickness of 0.2 to 1.0 mm can be used to achieve the highest tension conditions (11.2 kN). In particular, toothed belts with a cover layer thickness of about 0.5 mm (about 0.4 to 0.6 mm) are preferred. The toothed belt drive devices of Examples 27 to 29 are adapted to power transmission under high tension conditions and are advantageous for power transmission performance and tooth durability.

[0239] (Comparative Examples 12-14)

[0240] Comparative Examples 12-14 have toothed belts where the inner circumference of the core wire (steel cord) lacks a covering layer and reinforcing fabric, and the core wire is positioned in contact with the bottom surface of the belt teeth. In salt spray tests, rust formed on the core wire, and a decrease in belt strength was observed, indicating a lack of rust prevention.

[0241] Furthermore, the toothed belt drive devices in Comparative Examples 12 and 13 use a toothed belt with the core wire of (A) located at the position in contact with the bottom surface of the teeth, and the gap S between the front end of the pulley teeth and the bottom of the belt teeth is set to 0.5 mm (Comparative Example 12) and 0.8 mm (Comparative Example 13), respectively. Regarding operating performance, all conditions from low tension (7.0 kN) to high tension (11.2 kN) are classified as Grade B.

[0242] Furthermore, the toothed belt drive in Comparative Example 14 uses a toothed belt with the core wire of (C) in contact with the bottom surface of the teeth, without providing a gap S between the front end of the pulley teeth and the bottom of the belt teeth (the bottom of the belt teeth contacts the pulley teeth). Regarding operating performance, even under low tension (7.0 kN) conditions, it becomes a grade C due to wear at the bottom of the belt teeth, and it also becomes a grade C under further high tension conditions.

[0243] The results shown in Table 7 verify that even in toothed belts of higher size and higher strength specifications [tooth spacing 20mm, belt width 25mm, core wire 3 (diameter D=4.3mm, strength 22kN)], the method of the present invention, like the toothed belt shown in Table 1, can adapt to power transmission under high tension conditions and is a method that is beneficial to power transmission performance and tooth durability.

[0244] <Comparison and Verification in Table 8>

[0245] In Table 8, to compare the toothed belts of Example 28 (core spacing 6.0 mm, number of cores 4, belt strength 3.67 kN / mm) with variations in core spacing (Example 30) and (Example 31), the structures of the toothed belts of Examples 28, 30, and 31 are described. Additionally, Table 8 also describes the structure of the toothed belt of Example 32, which has the same belt strength (core structure and arrangement density) as Example 28 but with larger tooth dimensions. Furthermore, Table 8 also describes the structure of the toothed belt of Reference Example 5, which has the same belt strength (core structure and arrangement density) as Example 28 but with smaller tooth dimensions.

[0246] (Examples 30 and 31)

[0247] In Example 31, which reduced the core spacing and increased the number of cores to 5 (increased core density) compared to Example 28, the tape strength increased (4.48 kN / mm).

[0248] On the other hand, in Example 30, which increases the core spacing and reduces the number of cores to 3 (reducing the density of the core arrangement) compared to Example 28, the tape strength is reduced (tape strength 2.75kN / mm).

[0249] The toothed belts of Examples 30 and 31 showed no rust formation in the core wire during salt spray testing, with minimal reduction in belt strength, demonstrating excellent rust resistance. Regarding operational performance, in Example 31, the conditions from low tension (7.0 kN) to high tension (11.2 kN) were identical to those in Example 28, resulting in Grade A. In Example 30, under low tension (7.0 kN) conditions, it was Grade A; under high tension (8.0 kN, 11.2 kN) conditions, core wire breakage occurred before reaching 1.2 million cycles (1.1 million to 1.18 million cycles), resulting in Grade C. Each example represents a practical level depending on the application conditions.

[0250] The results above confirm that it is practical for use within the range of 4.9–7.3 mm core wire spacing and 2.75–4.48 kN / mm tape strength per 1 mm tape width.

[0251] (Example 32)

[0252] Example 32 differs from Example 28 in that the toothed belt with a pitch of 20 mm (tooth type G20M) has its teeth changed to a size with a pitch of 25 mm (tooth type G25M).

[0253] The toothed belt of Example 32 did not rust on the core wire during the salt spray test, and the reduction in belt strength was minimal, demonstrating excellent rust resistance. Regarding operational performance, it was also rated A under the same conditions as Example 28, from low tension (7.0 kN) to high tension (11.2 kN).

[0254] (Refer to Example 5)

[0255] Reference Example 5 is a toothed belt with a tooth pitch of 8 mm (tooth type S8M) compared to the toothed belt with a tooth pitch of 20 mm (tooth type G20M) in Example 28, while keeping the core wire structure and arrangement density the same. That is, it is an example with the same belt strength as Example 28, but with smaller tooth size.

[0256] The toothed belt in Example 5 showed no rust formation on the core wire during the salt spray test, with minimal reduction in belt strength, demonstrating excellent rust resistance. However, regarding operational performance, it also suffered from early failure (missing teeth) under low tension (7.0 kN) conditions, resulting in a grade D (unusable) rating (unsuitable for practical use).

[0257] <Comparison and Verification in Table 9>

[0258] In Table 9, the structures of the toothed strips of Examples 28, 33, and 34 are described in order to compare the cases where the thermoplastic elastomer is changed from polyester-type polyurethane to polyether-type polyurethane (Example 33) and polyamide-type (Example 34).

[0259] In addition, in Table 9, the structure of the toothed belts of Examples 28, 35 to 38 is described in order to compare the cases in which the hardness of the polyester-type polyurethane thermoplastic elastomer was changed from 50° to 30° (Example 35), 40° (Example 36), 60° (Example 37), and 70° (Example 38).

[0260] (Examples 33 and 34)

[0261] In Examples 33 and 34, where the polyester-type polyurethane thermoplastic elastomer in the toothed belt of Example 28 was changed to a polyether-type polyurethane elastomer, the belt strength was the same as in Example 28. The toothed belts of Examples 33 and 34 did not exhibit rust formation in the core wire during salt spray testing, and the reduction in belt strength was minimal, demonstrating excellent rust resistance. Regarding operational performance, the conditions from low tension (7.0 kN) to high tension (11.2 kN) were also rated as Class A, identical to Example 28.

[0262] (Examples 35-38)

[0263] In Examples 35 and 36, which reduced the hardness of the thermoplastic elastomer compared to Example 28, and Examples 37 and 38, which increased the hardness, the strip strength was the same as in Example 28. The toothed strips of Examples 35-38 did not rust on the core wire during salt spray testing, exhibited minimal reduction in strip strength, and demonstrated excellent rust resistance.

[0264] Regarding operating performance, in Example 37, where the hardness was increased, the condition from low tension (7.0 kN) to high tension (11.2 kN) was Grade A, identical to Example 28. Furthermore, in Example 38, with high hardness, it was Grade A under low tension (7.0 kN, 8.0 kN) conditions and Grade B under high tension (11.2 kN) conditions. On the other hand, in Example 36, where the hardness was decreased, it was Grade A under low tension (7.0 kN, 8.0 kN) conditions and Grade B under high tension (11.2 kN) conditions. Moreover, in Example 35, with low hardness, it was Grade B under low tension (7.0 kN, 8.0 kN) conditions, but under high tension (11.2 kN) conditions, it developed tooth chipping after 1 million cycles, becoming Grade C. Each example represents a level of practicality depending on the usage conditions.

[0265] <Comparison and Verification in Table 10>

[0266] Table 10 describes the structure of a toothed belt (tooth type G20M) of Example 39, which has a tooth pitch of 20 mm, a belt width of 35 mm, and uses core wire 4 (diameter D = 6.4 mm, strength 36 kN), as a toothed belt with a higher strength specification.

[0267] (Example 39)

[0268] The toothed belt drive device of Example 39 is based on Example 28, in which the thickness of the cover layer is set to 0.5 mm, but the structure and arrangement of the core wire are changed.

[0269] The toothed belt of Example 39 has a core wire spacing of 8.1 mm (4 core wires, belt strength of 4.11 kN / mm). The toothed belt of Example 39 showed no rust formation on the core wires during salt spray testing, with minimal reduction in belt strength, demonstrating excellent rust resistance. Regarding operational performance, conditions from low tension (7.0 kN) to high tension (11.2 kN) are classified as Grade A.

[0270] <Comparison and Verification in Table 11>

[0271] In Table 11, the dimensions of the toothed belt are the same as those of the toothed belt described in Patent Document 4 (tooth pitch 14 mm, tooth type G14M). However, as a low-strength specification toothed belt, the structures of the toothed belts in Examples 40, 41 and Reference Example 6 are described for toothed belts using core wire 5 (diameter D = 1.6 mm, strength 3.0 kN).

[0272] (Examples 40, 41 and Reference Example 6)

[0273] Examples 40, 41, and Reference Example 6 are toothed belt drive devices based on Example 2, in which the thickness of the cover layer is set to 0.5 mm, but with changes to the structure and arrangement of the core wires.

[0274] The toothed belt of Example 40 has a core wire spacing of 2.1 mm (9 core wires and a belt strength of 1.35 kN / mm), and the toothed belt of Example 41 has a core wire spacing of 1.8 mm (10 core wires and a belt strength of 1.50 kN / mm).

[0275] The toothed belts in Examples 40 and 41 did not exhibit rust formation in the core wire during salt spray testing, and showed minimal reduction in belt strength, demonstrating excellent rust resistance. Regarding operational performance, they were rated B under low tension (7.0 kN, 8.0 kN) conditions, but became rated C after core wire breakage at 1 million cycles under high tension (11.2 kN) conditions. Each example represents a practical level based on the applicable conditions.

[0276] In Reference Example 6, where the core wire spacing is reduced to the limit and the core wires are arranged without gaps, the belt strength is increased the most (1.65 kN / mm), but the operating performance is classified as Grade D due to early failure (belt ring breakage) under any tension condition.

[0277] The above results confirm that by setting a covering layer with a thickness of 0.2 to 1.0 mm between the bottom of the tooth and the core wire, toothed belts of various specifications and toothed belt drive devices, which have significantly different tooth size and belt strength (core wire structure and arrangement density), can adapt to power transmission under high load environment (high tension conditions), and can also adapt to rust prevention when installed at sea (offshore wind power generation).

[0278] The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. Various design changes can be made within the scope of the claimed protection.

[0279] The toothed belt drive device involved in this invention is not limited to use as a blade angle adjustment device or lifting and conveying device in a wind turbine generator, but can be used as any device.

[0280] • The toothed band can be either open-end or annular.

[0281] This application is based on Japanese Patent Application No. 2021-056839 filed on March 30, 2021, Japanese Patent Application No. 2021-206966 filed on December 21, 2021, and Japanese Patent Application No. 2022-045220 filed on March 22, 2022, the contents of which are incorporated herein by reference.

[0282] Label Explanation

[0283] 1. Toothed belt drive device;

[0284] 10. Toothed belt;

[0285] 11-core wire;

[0286] 12. Back;

[0287] 121 Covering layer;

[0288] 13. Toothed;

[0289] 14. Toothed bottom;

[0290] 50 Toothed pulley;

[0291] 53. Gear teeth;

[0292] 54. Bottom of the pulley teeth.

Claims

1. A toothed belt, characterized in that, have: Back; The core wire, embedded along the length of the belt in the back, is composed of twisted cord containing steel fibers; Multiple teeth are formed on the inner circumferential side of the back side, along the length of the belt; and A cover layer is disposed between the bottom of the teeth formed between the teeth and the core wire. The core wires are arranged at predetermined intervals along the width direction of the tape, and the sum of the intervals between adjacent core wires and the intervals between the ends of the toothed tape and the core wires in the width direction is in the range of 13% to 31% relative to the tape width. The thickness of the covering layer is in the range of 0.2 to 1.0 mm. The back, the teeth, and the cover layer are integrally formed from a thermoplastic elastomer.

2. The toothed belt according to claim 1, characterized in that, The spacing between the teeth is 14mm or more, and the height of the teeth is 5mm or more.

3. The toothed belt according to claim 1 or 2, characterized in that, The toothed belt is wound between a plurality of toothed pulleys, each having a plurality of pulley teeth formed on its outer periphery in a manner that engages with the belt teeth, such that the front ends of the belt teeth contact the bottoms of the pulley teeth formed between the pulley teeth and the front ends of the pulley teeth contact the bottoms of the belt teeth.

4. The toothed belt according to claim 3, characterized in that, The toothed belt is used in an environment where the tension applied to it varies due to external factors, typically being above 0.30 kN / mm and at a maximum of 1.10 kN / mm.

5. A toothed belt drive device, characterized in that, have: The toothed belt as described in claim 1 or 2; and Multiple toothed pulleys have multiple pulley teeth formed on their outer periphery in a manner that meshes with the teeth of the toothed belt. The belt is wound between multiple toothed pulleys in such a way that the front end of the belt contacts the bottom of the pulley teeth formed between the pulley teeth and the front end of the pulley teeth contacts the bottom of the belt teeth, so as to perform meshing transmission.

6. The toothed belt drive device according to claim 5, characterized in that, The toothed belt drive is used in an environment where the tension applied to the toothed belt varies due to external factors, normally being above 0.30 kN / mm and at a maximum of 1.10 kN / mm.

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