Toothed pulley, synchronous power transmission belt system, and method for installing toothed belt

Abstract

To provide a toothed pulley or the like which can attach a belt between pulleys so as to be capable of setting the attachment tension of the belt to a comparatively-high level even if the belt which is comparatively high in belt elasticity is attached to a pulley layout having no tension impartment mechanism which is in a common use in a prior art (the movement of an inter-axis distance, a tension pulley, a tensioner or the like).SOLUTION: A toothed pulley 1 in which a groove part 14 engaged with a tooth part 21 of a toothed belt 2 is formed at an external periphery comprises: a boss part 111 which can be connected to a rotating shaft; a first split pulley 12 and a second split pulley 13 which are attached to an external peripheral side of the boss part 111, and split into two pieces in a circumferential direction of the boss part 111; and a base member 11 for fixing a positional relationship of the first split pulley 12 and the second split pulley 13 in a rotating shaft direction. The first split pulley 12 is attachable to the external peripheral side of the boss part 111 in a state that the second split pulley 13 is not attached to the external peripheral side of the boss part 111.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a toothed pulley, a synchronous power transmission belt system using the same, and a method for installing a toothed belt in a synchronous power transmission belt system. [Background technology]

[0002] In the belt systems of automobile engines and general industrial machinery, meshing power transmission belts, including toothed belts, are widely used. Meshing power transmission belts transmit power by mechanically meshing the teeth of the belt with the grooves of the pulleys. In such meshing power transmission belts, the meshing must be maintained during operation to ensure a synchronous transmission system.

[0003] However, if the belt stretches and becomes loose while in motion, it will result in poor meshing (problems such as tooth skipping will occur), so basically, a belt with a relatively high tensile modulus of elasticity (hereinafter referred to as belt modulus of elasticity) and little stretch is required.

[0004] Conventionally, the following method has been applied to install a toothed belt (hereinafter sometimes simply referred to as a "belt"; the belt width is assumed to be 20 mm) having a relatively high belt elasticity between pulleys.

[0005] (A) The belt is suspended in a relaxed state between two or more pulleys, and tension is applied to the belt by pushing or pulling the belt with a tensioner (tension pulley). (B) With the belt suspended between two or more pulleys in a relaxed state, tension is applied to the belt by moving at least one pulley shaft to increase the center distance between the pulleys. (C) A method of mounting a belt on a pulley layout that does not have the above-mentioned tensioning mechanism (axis distance movement, tension pulley, tensioner, etc.), in which the belt is suspended on a pulley layout (two or more pulleys) whose pulley layout circumference (see definition below) is the same as or slightly shorter than the belt reference circumference (see definition below), and the belt is mounted between the pulleys in a state in which almost no tension is applied to the belt when mounted.

[0006] In particular, by adopting the method (C) above, conventional tensioning mechanisms such as those described in (A) and (B) above (such as tension pulleys and tensioners) are no longer necessary, which contributes to reducing the weight and cost of the synchronous transmission belt system. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 56-31557 [Patent Document 2] Japanese Patent Application Publication No. 08-24249 Summary of the Invention [Problem to be solved by the invention]

[0008] In the case of a belt with a relatively high belt elastic modulus (for example, about 200 to 400 KN for a belt width of 20 mm), the above method (C) allows the belt to be attached by hand (without tools) to a pulley layout that does not have the conventional tensioning mechanism (axis distance movement, tension pulley, tensioner, etc.) described above, but even if the belt is attached with almost no tension (initial tension) when attached (for example, only a tension of about 100 N is applied when attached), the belt system is a meshing transmission and therefore has a certain level of transmission capacity.

[0009] However, in order to improve the belt's power transmission performance (such as resistance to tooth skipping) to accommodate higher load applications, it is essential to increase the tension (initial tension) applied to the belt when it is installed.

[0010] In the above method (C), in order to set the tension (initial tension) of a belt having a relatively high belt elasticity (e.g., about 200 to 400 KN) at the time of installation to a relatively high level (e.g., about 200 to 400 N), it is necessary to arrange the pulley layout so that the pulley layout circumference is slightly (e.g., about 0.05% to 0.1%) longer than the belt reference circumference.

[0011] However, because the belt is based on a belt with a relatively high elastic modulus (for example, about 200 to 400 KN), it is difficult to install the belt in the pulley layout, and this was not possible.

[0012] In this regard, we searched for literature related to conventional toothed pulleys as a means for solving the above problem, and found Patent Document 1 and Patent Document 2. However, these documents did not contain any information about the above problem, any means for solving the problem, or any suggestions therefor.

[0013] Therefore, an object of the present invention is to provide a toothed pulley or the like that enables a belt to be installed between pulleys so that the tension of the belt can be set to a relatively high level when installed, even when a belt with a relatively high belt elasticity is installed in a pulley layout that does not have a conventional tensioning mechanism (axis distance movement, tension pulley, tensioner, etc.). [Means for solving the problem]

[0014] The present invention provides a toothed pulley having a groove formed on its outer periphery, the groove meshing with the teeth of a toothed belt, A boss portion connectable to a rotating shaft; A plurality of split pulleys attached to an outer circumferential side of the boss portion and having a shape divided into a plurality of pulleys in a circumferential direction of the boss portion; A fixing means for fixing a positional relationship of the plurality of split pulleys in the rotation axis direction; Equipped with Among the plurality of split pulleys, some of the split pulleys are characterized in that they are attachable to or integrated with the outer circumferential side of the boss portion while the remaining split pulleys are not attached to the outer circumferential side of the boss portion.

[0015] According to the above configuration, by providing a pulley layout in such a manner that, as viewed in the direction of the rotation axis of some of the split pulleys that are attached to the outer periphery of the boss portion or integrated with the outer periphery of the boss portion, an arc portion connecting the outer edges of the groove portions formed on the outer periphery of some of the split pulleys remains in the inner region of the circumference of the pulley layout including the toothed pulley, it is possible to shorten the circumference (L1) of the pulley layout including the toothed pulley before the toothed belt is attached relative to the belt reference circumference (L0) of the toothed belt in advance. Therefore, a toothed belt with a relatively high belt elasticity can be easily suspended on a pulley layout including some of the split pulleys. The toothed pulley including some of the split pulleys can be rotated to impart tension to the toothed belt during installation, and therefore the toothed pulley functions as a tension imparting mechanism when the toothed belt is installed in the pulley layout. Then, by attaching the remaining split pulley to the outer periphery of the boss portion via a fixing means, it can be applied to a synchronous power transmission belt system as a toothed pulley having the exact same appearance (annular shape) and function as a normal toothed pulley. Therefore, according to the above configuration, even when a toothed belt having a relatively high belt elasticity is attached to a pulley layout that does not have a conventional tensioning mechanism (such as an axis distance movement, tension pulley, or tensioner), the tension of the toothed belt when attached can be set to a relatively high level.

[0016] In the present invention, in the toothed pulley, the number of the plurality of split pulleys may be two.

[0017] According to the above configuration, compared to a case where the number of the multiple split pulleys is three or more, the effort required for manufacturing the toothed pulleys and the effort required for fitting the toothed belt between the pulleys (assembly of the remaining split pulleys) can be reduced.

[0018] In the toothed pulley of the present invention, the groove may be shaped to extend in the direction of the rotation axis.

[0019] According to the above configuration, the grooves extend parallel to the pulley width direction. This makes it easier to attach the toothed belt to the toothed pulley (more specifically, it is easier to fit the remaining split pulleys to some of the split pulleys in the pulley width direction (rotation axis direction)) compared to a toothed pulley other than a straight toothed pulley (for example, a helical toothed pulley having grooves arranged diagonally with respect to the pulley width direction). In addition, this makes it possible to expand the allowable range of the toothed belt winding angle, thereby further increasing the freedom of pulley layout.

[0020] Further, in the toothed pulley of the present invention, the fixing means is configured such that the boss portion and a flange portion extending radially outward from one side of the boss portion are integrally formed, Furthermore, the present invention may be characterized by including a fastening member for fastening the plurality of split pulleys and the flange portion together.

[0021] According to the above-mentioned configuration, the positional relationship in the rotation axis direction of the plurality of split pulleys on the outer periphery side (radially outer side) of the boss portion can be more reliably fixed. Also, the degree of freedom in the design (configuration) of the toothed pulley can be increased.

[0022] Moreover, in the toothed pulley of the present invention, the flange portion may extend from one side of the boss portion to at least an outer edge of the groove portion.

[0023] According to the above configuration, it is possible to prevent the toothed belt from falling off the toothed pulley, and to improve the running stability of the toothed belt along the pulley layout (path of the toothed belt).

[0024] In addition, the present invention may be characterized in that, in the above-mentioned toothed pulley, the split pulley and the fixing means are structured so that a concave recess formed on one side and a convex protrusion formed on the other side are concentrically fitted together.

[0025] According to the above configuration, the split pulleys and the fixing means can be made to have a spigot structure, so that the toothed pulley (final shape) after assembling the multiple split pulleys and the fixing means can be a toothed pulley with exactly the same external shape (annular shape) and function as a normal toothed pulley, with higher dimensional accuracy.

[0026] In addition, the present invention may be characterized in that, in the above-mentioned toothed pulley, the split pulley has the convex portion on one side and the fixing means has the concave portion on one side, and the convex portion and the concave portion are configured to be concentrically engageable with each other.

[0027] Contrary to this configuration, if a configuration is used in which the split pulley has a recess on one side and the fixing means has a protrusion on one side, when a toothed pulley with only some of the split pulleys attached to the outer periphery of the boss portion is used to attach a toothed belt to a pulley layout (temporarily fastening), there is a risk that the toothed belt will inadvertently ride up onto the protrusion protruding on one side of the fixing means, especially during the process of applying tension to the toothed belt, and the toothed belt will be damaged. However, according to the present configuration, since there is no protruding projection on one side of the fixing means, there is no risk of the toothed belt being damaged when the toothed belt is attached to the pulley layout.

[0028] In the toothed pulley of the present invention, the plurality of split pulleys may be circumferentially separated at a bottom surface of the groove.

[0029] Contrary to this configuration, if the multiple split pulleys are divided circumferentially at parts other than the bottom surface of the groove portion (for example, parts facing the tooth base and tooth bottom of the belt), when a toothed pulley with only some of the split pulleys attached to the outer periphery of the boss portion is used to attach the toothed belt to a pulley layout (temporarily fastening), there is a risk that, especially during the process of applying tension to the toothed belt, the relatively thin belt parts other than the teeth (tooth base and tooth bottom) will come into contact with the outer periphery end (corner) of the split surface, causing the toothed belt to bend, resulting in cracks or breakage. However, according to the present configuration, a dividing surface is formed starting from the bottom surface of the groove portion, and the pulley is divided in the circumferential direction. Therefore, when the toothed belt is attached to the pulley layout, it is the tooth tips of the toothed belt that come into contact with the outer peripheral end (corner) of the dividing surface, thereby preventing the occurrence of the above-mentioned problems (cracks, etc.).

[0030] The present invention also provides a synchronous power transmission belt system including a toothed belt having a plurality of teeth arranged at predetermined intervals along a belt longitudinal direction, and a pulley layout including two or more toothed pulleys arranged at a distance from each other, to which the toothed belt is attached, At least one of the two or more toothed pulleys is a toothed pulley according to any one of claims 1 to 8, the part of the split pulleys functions as a belt mounting pulley used when mounting the toothed belt to the pulley layout in a state in which the remaining split pulleys are not mounted to the outer periphery side of the boss portion and are mounted or integrated with the outer periphery side of the boss portion, This is characterized in that, before the toothed belt is attached to the pulley layout, when viewed in the direction of the rotation axis, an arc portion connecting the outer edges of the groove portions formed on the outer periphery of some of the split pulleys is configured to be arranged in a manner that remains within the inner region of the circumference of the pulley layout including the toothed pulley.

[0031] According to the above configuration, even when a toothed belt having a relatively high belt elasticity is installed in a pulley layout of a synchronous power transmission belt system that does not have a conventional tensioning mechanism (such as an axis distance movement, tension pulley, or tensioner), the tension of the toothed belt when installed can be set to a relatively high level.

[0032] Moreover, the present invention may be characterized in that in the synchronous power transmission belt system, only one of the two or more toothed pulleys is the toothed pulley described above.

[0033] According to the above configuration, it is possible to minimize the manufacturing costs of the synchronous power transmission belt system (particularly the pulley layout) and the labor required for mounting the toothed belt on the pulley layout.

[0034] Furthermore, in the above-mentioned synchronous power transmission belt system, the central angle of the arc portion, as viewed in the direction of the rotation axis, may be equal to or greater than a winding angle of the toothed belt about the toothed pulley, and the central angle of the arc portion, as viewed in the direction of the rotation axis, may be such that, with the arc portion remaining in the inner region of the circumference of the pulley layout including the toothed pulley, a circumferential length (L1) of the pulley layout is within a range less than a belt reference circumference (L0) of the toothed belt.

[0035] According to the above-mentioned configuration, ease of installation of the toothed belt (particularly ease of installation of the remaining divided pulleys on the outer periphery of the boss portion) can be reliably ensured.

[0036] The present invention also provides a method for mounting the toothed belt to the pulley layout in the above-mentioned synchronous power transmission belt system, comprising the steps of: a preparation step of connecting the boss portion to a rotation shaft, and arranging the pulley layout in such a manner that, as viewed in the direction of the rotation shaft of the split pulley, which is attached to the outer periphery of the boss portion or integrated with the outer periphery of the boss portion, an arc portion connecting the outer edges of the groove portion formed on the outer periphery of the split pulley remains within an inner region of the circumference of the pulley layout including the toothed pulley; a suspension step of suspending the toothed belt around the pulley layout provided in the preparation step; a tension applying step of rotating the toothed pulley including the part of the split pulleys to apply tension during installation to the toothed belt; and an assembling step of attaching the remaining split pulley to the outer periphery of the boss portion via the fixing means.

[0037] According to the above method, even when a toothed belt having a relatively high belt elasticity is installed in a pulley layout that does not have a conventional tensioning mechanism (such as an axis distance movement, tension pulley, or tensioner), the tension of the toothed belt when installed can be set to a relatively high level. [Brief description of the drawings]

[0038] [Figure 1] FIG. 1 is a perspective view of a toothed pulley according to an embodiment (Example 1). [Diagram 2] 1 is a six-view diagram of a toothed pulley according to the present embodiment (Example 1). [Diagram 3] FIG. 2 is an exploded view of the toothed pulley of the present embodiment (Example 1). [Figure 4] FIG. 2 is a perspective view of a first split pulley (Example 1). [Diagram 5] FIG. 2 is a perspective view of a belt mounting pulley (a toothed pulley in a state in which a first split pulley is attached to a base member) (Example 1). [Figure 6] 1A is a diagram illustrating a preferred fitting form between the first split pulley and the base member, and FIG.1B is a diagram illustrating an unpreferable fitting form between the first split pulley and the base member. [Figure 7] FIG. 2 is a perspective view of a portion of a toothed belt used in the synchronous power transmission belt systems of the examples and comparative examples. [Figure 8] FIG. 4 is an explanatory diagram of the shape of a tooth portion of a toothed belt. [Figure 9] 1 is a schematic diagram showing a state of a preparation step in a synchronous power transmission belt system using a toothed pulley according to the present embodiment (Example 1). FIG. [Figure 10] 1 is a schematic diagram showing a state of a suspension step in a synchronous power transmission belt system using a toothed pulley according to the present embodiment (Example 1). FIG. [Figure 11] 1 is a schematic diagram showing a state of a tension applying step in a synchronous power transmission belt system using a toothed pulley according to the present embodiment (Example 1). [Figure 12]1 is a schematic diagram showing a state of a tension applying step in a synchronous power transmission belt system using a toothed pulley according to the present embodiment (Example 1). [Figure 13] 1 is a schematic diagram showing an assembly step of a synchronous power transmission belt system using a toothed pulley according to the present embodiment (Example 1). FIG. [Figure 14] 5A is a schematic diagram illustrating a state of a preparation step, a tensioning step, and a mounting step in a synchronous power transmission belt system using a toothed pulley of another embodiment (Example 2). FIG. [Figure 15] 11A is a schematic diagram showing a state of a tensioning step and an assembly step in a synchronous power transmission belt system using a toothed pulley of another embodiment (Example 2). FIG. [Figure 16] 10A to 10C are schematic diagrams illustrating a preparation step and an assembly step in a synchronous power transmission belt system using a toothed pulley according to another embodiment (Example 3). [Figure 17] FIG. 6 is a six-view diagram of a toothed pulley according to another embodiment (Example 2). [Figure 18] FIG. 11 is a six-view diagram of a toothed pulley according to another embodiment (Example 3). [Figure 19] FIG. 2 is a perspective view of a conventional toothed pulley (Comparative Examples 1 and 2). [Figure 20] 1A is a schematic diagram of a synchronous power transmission belt system using a conventional toothed pulley (Comparative Example 1), and FIG. 1B is a diagram illustrating a problem (issue) of the conventional toothed pulley (Comparative Example 2). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] (Embodiment) A toothed pulley 1 according to an embodiment of the present invention (Example 1 described later), a synchronous power transmission belt system 100 including the toothed pulley 1, and a toothed belt 2 in the synchronous power transmission belt system 100 will be described below.

[0040] (Toothed pulley 1) As shown in FIG. 1, the toothed pulley 1 is a drive pulley having a boss portion 111 connectable to a rotating shaft and a groove portion 14 formed on the outer periphery of the boss portion 111 to mesh with the teeth portion 21 of the toothed belt 2.

[0041] As shown in Fig. 3, the toothed pulley 1 is attached to the outer periphery of a boss portion 111, and has a structure including a first split pulley 12 and a second split pulley 13, each of which is divided into two in the circumferential direction of the boss portion 111, and a base member 11 (corresponding to a fixing means) that fixes the positional relationship in the rotation axis direction of the first split pulley 12 and the second split pulley 13. The first split pulley 12 can be attached to the outer periphery of the boss portion 111 while the second split pulley 13 is not attached to the outer periphery of the boss portion 111. In other words, the toothed pulley 1 can maintain a state in which only the first split pulley 12 is attached to the outer periphery of the boss portion 111, as shown in Fig. 5.

[0042] (First split pulley 12 and second split pulley 13) In this embodiment, the configuration includes a first split pulley 12 and a second split pulley 13 that are split into two in the circumferential direction of the boss portion 111, but the number of splits may be three or four. However, the number of split pulleys is preferably two as shown in this embodiment (see FIG. 3). When the number of split pulleys is two, the effort required for manufacturing the toothed pulley 1, the effort required for fitting the toothed belt 2 between the toothed pulley 1 and the driven pulley 102, and the effort required for assembling the split pulleys to the base member 11 can be reduced compared to when the number of splits (number of split pulleys) is three or more.

[0043] Furthermore, the divided surface 12a of the first split pulley 12 and the divided surface 13a of the second split pulley 13 may be formed to extend along the radial direction of the toothed pulley 1 as in this embodiment (see Figure 3), or may be formed to include a surface extending in a direction inclined relative to the radial direction of the toothed pulley 1.

[0044] In addition, a groove portion 1 formed on the outer periphery of the first split pulley 12 and the outer periphery of the second split pulley 13 The pulley 4 extends in the direction of the rotation axis. That is, straight teeth are formed on the outer periphery of the first split pulley 12 and the outer periphery of the second split pulley 13 (for example, a shape corresponding to a general straight tooth).

[0045] Furthermore, the shape of groove portion 14 should be formed to correspond to the tooth shape of the toothed belt 2 to be attached, as long as synchronous transmission (intermeshing transmission) is possible, and groove portion 14 may have a shape extending in a direction inclined with respect to the rotation axis direction (for example, a shape corresponding to helical teeth (teeth with an oblique contact angle on the tooth surface)).

[0046] Here, in the case where the grooves 14 formed on the outer periphery of the first split pulley 12 and the outer periphery of the second split pulley 13 have a straight tooth shape extending in the direction of the rotation axis as in the present embodiment, from the viewpoint of suppressing damage caused by contact of the outer peripheral end (corner C) of the split surface 12a of the first split pulley 12 and the split surface 13a of the second split pulley 13 with the toothed belt 2 when the toothed belt 2 is attached, and from the viewpoint of improving the attachability of the toothed belt 2 (the workability in the assembly step described later), the first split pulley 12 and the second split pulley 13 are divided in the circumferential direction by the bottom surface 14a of the grooves 14 as shown in FIG. 2. That is, the first split pulley 12 and the second split pulley 13 are divided by a surface connecting the opposing bottom surfaces 14a as shown in FIG. 2. In this way, it is preferable that the shape of the grooves 14 is straight tooth, which is a shape that easily becomes the starting point of the split surface 12a and the split surface 13a on the bottom surface 14a.

[0047] Furthermore, even if the groove portion 14 has a helical tooth shape, by chamfering the outer peripheral ends (corner C) of the dividing surfaces 12a and 13a, it is possible to some extent suppress damage to the toothed belt 2 caused by contact with the outer peripheral ends (corner C) of the dividing surfaces 12a and 13a when the toothed belt 2 is attached.

[0048] If the first split pulley 12 and the second split pulley 13 are configured to be divided circumferentially at a portion other than the bottom surface 14a of the groove portion 14 (for example, the portion facing the tooth base or tooth bottom of the toothed belt 2), when the toothed pulley 1 is used as a belt mounting pulley with only the first split pulley 12 attached to the base member 11 and the toothed belt 2 is attached to the pulley layout (temporarily fastened), particularly during the process of applying tension to the toothed belt 2, the relatively thin portions of the toothed belt 2 other than the tooth portion 21 (the tooth base and tooth bottom) may come into contact with the outer peripheral end portion (corner C) of the split surface 12a, causing the toothed belt 2 to bend, resulting in a risk of cracking or breaking.

[0049] However, according to the above configuration, the dividing surface 12a and the dividing surface 13a are formed starting from the bottom surface 14a of the groove portion 14, and the toothed pulley 1 is divided in the circumferential direction. Therefore, when the toothed belt 2 is attached to the pulley layout, it is the tooth tip portion of the toothed belt 2 that comes into contact with the outer peripheral end portion (corner C) of the dividing surface 12a, thereby preventing the occurrence of the above-mentioned defects (cracks, etc.).

[0050] (Base member 11) The base member 11 has a structure in which a boss portion 111 and a circular flange 112 extending radially outward from one side of the boss portion 111 are integrally formed. A groove 111a that fits into a key groove on a rotating shaft is formed on the inner circumference of the boss portion 111, so that the rotating shaft and the toothed pulley 1 can be fixed so as not to rotate relative to each other. With the first split pulley 12 and the second split pulley 13 attached, the flange 112 extends from one side of the boss portion 111 to at least the outer edge of the groove portion 14, and in this embodiment, the flange 112 has a shape slightly larger than the outer edges of the first split pulley 12 and the second split pulley 13 (see FIG. 2).

[0051] Further, eight holes 114 are formed in an annular shape on the outer side of the boss portion 111 in the flange 112. The first split pulley 12 can be fixed to the flange 112 by fastening four holes 12b (see FIG. 4) formed in the first split pulley 12 to four holes 114 formed in the flange 112 with rivets or screw members (corresponding to fastening members). Similarly, the second split pulley 13 can be fixed to the flange 112 by fastening four holes 13b (not shown) formed in the second split pulley 13 to four holes 114 formed in the flange 112 with rivets or screw members. In this way, by making it possible to fix the first split pulley 12 and the second split pulley 13 to the flange 112 with rivets or screw members, the positional relationship in the rotation axis direction of the first split pulley 12 and the second split pulley 13 can be more reliably fixed on the outer circumferential side of the boss portion 111 of the base member 11. In addition, the degree of freedom in designing (configuring) the toothed pulley 1 can be increased.

[0052] As a means for fixing the flange 112 and the first split pulley 12, or the flange 112 and the second split pulley 13, for example, similar to the configuration in which the rotating shaft and the boss portion 111 are fitted with a key groove to fix them so that they cannot rotate relative to each other, a configuration in which the second split pulley 13 and the boss portion 111 are fitted with a key groove to prevent them from rotating relative to each other and fastened with rivets or screw members to fix the positional relationship of the first split pulley 12 and the second split pulley 13, which are adjacent in the circumferential direction, may be used (not shown).

[0053] (Spigot structure) As shown in Figs. 3 and 4, the first split pulley 12 has a semicircular convex portion 12c formed on a side surface facing the flange 112. Similarly, the second split pulley 13 has a semicircular convex portion 13c formed on a side surface facing the flange 112. Meanwhile, as shown in Fig. 3, the flange 112 has a circular concave portion 113 formed along the outer periphery of the boss portion 111 on a side surface facing the first split pulley 12 and the second split pulley 13. The convex portion 12c of the first split pulley 12 and the concave portion 113 of the flange 112 are concentrically fitted together, and similarly, the convex portion 13c of the second split pulley 13 and the concave portion 113 of the flange 112 can be concentrically fitted together. That is, the first split pulley 12 and the flange 112, and the second split pulley 13 and the flange 112 have a spigot structure. This allows the toothed pulley 1 (final shape) after the first split pulley 12 and the second split pulley 13 are attached to the base member 11 to be a toothed pulley with exactly the same external shape (annular) and function as a normal toothed pulley, with higher dimensional accuracy.

[0054] The convex portion and the concave portion of the spigot structure may be arranged in reverse. That is, a semicircular concave portion may be formed on the side surface of the first split pulley 12 and the second split pulley 13 facing the flange 112, and a circular convex portion may be formed on the side surface of the flange 112 facing the first split pulley 12 and the second split pulley 13, to form a spigot structure. However, if a convex portion is formed on the flange 112 side, when the toothed belt 2 is attached to the pulley layout (temporarily attached) using the toothed pulley 1 in a state where only the first split pulley 12 is attached to the outer periphery of the boss portion 111, as shown in FIG. 6(B), especially in the process of applying tension to the toothed belt 2, the toothed belt 2 may inadvertently ride up on the convex portion protruding from the flange 112, which may cause damage to the toothed belt 2. Therefore, by forming a recess 113 on the flange 112 side as in this embodiment (see Figure 6 (A)), there is no protrusion protruding from the flange 112, so there is no risk of the toothed belt 2 being damaged when the toothed belt 2 is attached to the pulley layout.

[0055] The spigot structure between the first split pulley 12 and the flange 112, and between the second split pulley 13 and the flange 112 is not essential, and does not have to be configured as a spigot structure (not shown).

[0056] (Material used for toothed pulley 1) The material of the toothed pulley 1 (each of the components of the base member 11, the first split pulley 12, and the second split pulley 13) is not particularly limited. It may be a metal such as iron, an iron alloy, or an aluminum alloy, or a resin (cast nylon resin, etc.). From the viewpoint of suppressing thermal expansion (dimensional change) due to temperature change, it is preferable to use an iron alloy (for example, a nickel-iron alloy) that has a relatively small linear expansion coefficient.

[0057] (Manufacturing method of toothed pulley 1) The toothed pulley 1 (each of the components of the base member 11, the first split pulley 12, and the second split pulley 13) can be manufactured by machining (cutting, etc.), as well as by cold forging, hot forging, die casting (die casting, etc.), powder metallurgy (a method of sintering a green compact obtained by compressing and molding metal powder), or by a known method that combines these.

[0058] The first split pulley 12 and the second split pulley 13 may be manufactured separately by the above-mentioned method, but from the viewpoint of ensuring a higher level of manufacturing quality (outer diameter roundness, etc.) of the toothed pulley 1 including the first split pulley 12 and the second split pulley 13, it is preferable to manufacture them in an integrated shape (without division) like a normal toothed pulley, and then divide them into two, the first split pulley 12 and the second split pulley 13, using a cutting processing method such as wire cut electric discharge machining, laser processing, ultrasonic processing, etc.

[0059] (Synchronous power transmission belt system 100) In the synchronous power transmission belt system 100, in a pulley layout in which a toothed belt 2 is wound around two or more toothed pulleys, at least one of the two or more toothed pulleys is configured with the above-mentioned toothed pulley 1. Note that the number of toothed pulleys 1 according to this embodiment used in a synchronous power transmission belt system having a plurality of toothed pulleys may be two or more, but is preferably one.

[0060] Specifically, the synchronous transmission belt system 100 of this embodiment has a pulley layout consisting of a drive pulley 101 (toothed pulley 1) and a driven pulley 102 (conventional toothed pulley) arranged at a distance from each other (fixed position), as shown in FIG. 13, and the toothed pulley 1 of this embodiment is used for the drive pulley 101.

[0061] 5, the toothed pulley 1 is attached to a rotating shaft with only the first split pulley 12 attached to the flange 112 (with only the first split pulley 12 attached to the outer periphery of the boss portion 111), and functions as a belt attachment pulley used when attaching the toothed belt 2 between the drive pulley 101 (toothed pulley 1) and the driven pulley 102. From another perspective, the toothed pulley 1 is attached to a rotating shaft with the second split pulley 13 not attached to the flange 112 (with the second split pulley 13 not attached to the outer periphery of the boss portion 111), and is used as a belt attachment pulley. Specifically, before the toothed belt 2 is attached between the driving pulley 101 (toothed pulley 1) and the driven pulley 102, as shown in FIG. 9, when viewed in the direction of the rotation axis, the arc portion 12d connecting the outer edges of the groove portion 14 formed on the outer periphery of the first split pulley 12 is arranged in such a manner that it remains in the inner circumferential region of the pulley layout including the toothed pulley 1.

[0062] (Toothed belt 2) As shown in FIG. 7 , the toothed belt 2 used in the synchronous power transmission belt system 100 has a back portion 23 in which a core wire 22 is embedded, a plurality of tooth portions 21 arranged at predetermined intervals along the longitudinal direction of the belt on one surface of the back portion 23, and a tooth cloth 24 covering the inner peripheral side of the toothed belt 2 including the tooth portions 21.

[0063] (Core 22) The core wire 22 is embedded in the back portion 23 of the toothed belt 2. The core wire 22 is composed of a twisted cord formed by twisting together a plurality of strands. One strand may be formed by bundling and paralleling filaments (long fibers).

[0064] When a relatively high belt elastic modulus (e.g., about 200 to 400 KN) is required as in this embodiment, the filament material of the core wire 22 is made of a high-strength, low-elongation material such as high-strength glass fiber, and the twisting configuration such as the filament thickness, the number of filament bundles, the number of strands, and the twisting method are appropriately selected to configure the core wire 22 (twisted cord) to have a thickness (e.g., a diameter of about 1 mm) that matches the target belt elastic modulus. The twisted cord used as the core wire 22 is preferably subjected to an adhesive treatment to enhance adhesion to the back part 23, and is subjected to an adhesive treatment by, for example, immersing it in a resorcin-formalin-latex treatment liquid (RFL treatment liquid) and then heating and drying it to form a uniform adhesive layer on the surface.

[0065] (Rubber-like elastic body constituting the back portion 23 and the teeth portion 21) The rubber-like elastic body constituting the back portion 23 and the toothed portion 21 of the toothed belt 2 is formed by crosslinking a rubber composition. As the rubber component of this rubber composition, chloroprene rubber (CR), nitrile rubber, hydrogenated nitrile rubber (HNBR), ethylene-propylene copolymer (EPM), ethylene-propylene-diene terpolymer (EPDM), styrene-butadiene rubber, butyl rubber, chlorosulfonated polyethylene rubber, etc. are used. These rubber components can be used alone or in combination. Although details are omitted, the rubber composition constituting the back portion 23 and the toothed portion 21 is prepared by blending carbon black, a plasticizer, a crosslinking agent, and various other conventional additives (or compounding agents) as necessary.

[0066] (Toothcloth 24) The tooth cloth 24 covering the surface of the tooth portion 21 and a part of one surface of the back portion 23 (i.e., the surface of the tooth bottom portion 21a of the tooth portion 21) is generally made of a woven fabric made of aliphatic polyamide fibers (nylon fibers) such as nylon 6 or nylon 6,6, which is subjected to adhesive treatment. In this case, a fiber fabric having a warp thread (belt width direction) of nylon 6 and a weft thread (belt length direction) of nylon 6 containing elastic yarns having elasticity (urethane elastic yarns having elasticity in themselves, or woolly processed fibers having elasticity processing) and a twill weave is used as the tooth cloth 24. The above fiber fabric is immersed in RFL liquid and used as the tooth cloth 24. The thickness of the tooth cloth 24 (thickness at the cross section of the toothed belt 2) is, for example, about 0.2 mm. The tooth cloth 24 is not limited to the above. The fiber fabric used as the tooth cloth 24 may be made of polyester, aramid fiber, or other materials, either alone or in combination, depending on the load of each belt system.

[0067] (Tooth shape of tooth portion 21) The tooth shape of the tooth portion 21 may be a tooth shape generally called straight teeth or a tooth shape called helical teeth (teeth with an oblique contact angle on the tooth surface) as long as synchronous transmission (meshing transmission) is possible. The toothed belt 2 used in the synchronous transmission belt system 100 of this embodiment has straight teeth.

[0068] Straight tooth shapes can be selected from the following known tooth shapes, as well as modified or special shapes, to suit the intended use of the belt system: H-tooth shape, which has a nearly semicircular cross section, T-tooth shape, which has a trapezoidal cross section, and S-tooth shape (STPD type), which has two outwardly bulging convex curved surfaces (arcuate surfaces) connected by a flat surface (see Fig. 8).

[0069] (Belt reference circumference) First, the terms used in the following description will be explained. The tension during installation refers to the tension applied in the longitudinal direction of the belt immediately after the belt is installed on the pulley layout. The pulley layout circumference refers to the length of a line (pulley layout circumference) (i.e., the belt path) formed in a ring shape along the outer circumference of two or more pulleys that are spaced apart from each other and on which the belt is attached, connecting the outer circumferences of the pulleys. The reference circumference of a belt refers to the length in the longitudinal direction of the belt when the belt is wound around two flat pulleys (pulleys with no grooves on the outer circumferential surface) with the toothed surface facing outward, and is installed so that it is suspended between them, and a tension sufficient to remove any deflection in the longitudinal direction of the belt is applied to the belt (in the case of a toothed belt with a belt width of 20 mm used in the evaluation of the examples, the level of tension sufficient to remove any deflection in the longitudinal direction of the belt is approximately 100 N).

[0070] The reference circumference (L0) of the toothed belt 2 of this embodiment is determined by estimating the shortened length (shortened length rate) from the above-mentioned (3) belt circumference (L) after the belt is worn (after tension is applied when worn) (corresponding to the pulley layout circumference (L2) after the belt is worn) based on a balance between (1) the belt elastic modulus (belt tensile stiffness), (2) tension when worn, and (3) belt circumference (L) after the belt is worn (after tension when worn) (pulley layout circumference (L2)).

[0071] For example, in a synchronous power transmission belt system 100, the belt width is 20 mm, (1) the belt elastic modulus is about 200 to 400 KN, (2) the tension when installed is about 200 to 400 N, and (3) the belt circumference (L) after the belt is installed (after tension when installed) (corresponding to the pulley layout circumference (L2) after the belt is installed) is 840 mm, the measurement history (data) of the belt elastic modulus for each belt type, that is, the belt tension T (N) and the belt elongation amount Based on the stress-strain curve (SS diagram) showing the relationship with (L-L0) (mm), the shortened length (shortened length rate) from the belt circumference (L) after installation between the pulleys is estimated to be approximately 0.4 mm (0.05%) to 0.8 mm (0.1%), and the reference circumference (L0) of the toothed belt 2 (corresponding to the belt circumference when tension sufficient to remove the longitudinal deflection of the belt is applied) is determined to be approximately 839.2 mm to 839.6 mm.

[0072] (Belt elasticity) The belt elastic modulus of the toothed belt 2 is about 200 to 400 kN when the belt width is 20 mm, which is a level suitable for applications with higher loads. If the belt elastic modulus is less than 200 kN, the phase shift angle between the rotation shaft of the driving pulley 101 and the rotation shaft of the driven pulley becomes large (for example, becomes larger than 2°), and there is a risk of losing synchronism. On the other hand, if the belt elastic modulus exceeds 400 kN, when the synchronous power transmission belt system 100 is used in a belt system in which the main body of the system thermally expands, such as for automobile engine applications, the belt runs in a state in which the belt tension due to the change in the center distance increases excessively, accelerating bending fatigue of the core wire or wear of the tooth cloth, and there is a risk of the durability of the belt decreasing early. Here, the belt elastic modulus is measured by the following method.

[0073] (Method of measuring belt elasticity) A pair of pulleys (30 teeth) are attached to the lower fixed part and the upper load cell connection part of an autograph (for example, Shimadzu Corporation's "AGS-J10kN"), and the toothed belt 2 is placed between the pulleys. Next, the upper pulley is raised, and an initial tension T0 (approximately 100 N) is applied to the toothed belt 2 to the extent that the longitudinal deflection is removed. The position of the upper pulley in this state is set as the initial position, and the belt circumference at this time is set as the belt reference circumference (L0) (mm), and the upper pulley is raised at a speed of 10 mm / min. In the stress-strain curve (SS diagram) showing the relationship between the measured belt tension T (N) and the belt elongation (L-L0) (mm), the increase (T-T0) (N) in the belt tension T (N) from the initial tension state is divided by the ratio of the belt elongation (L-L0) to the belt reference circumference (L0) [(L-L0) / L0] (dimensionless) to calculate the value (N) (corresponding to the so-called "tensile stiffness of the belt"), and this value is defined as the belt elastic modulus (N).

[0074] (Tension when worn) The level of tension when installed required for the toothed belt 2 capable of handling higher load applications, which is the object of the present application, is equivalent to the tension applied to the belt when an autotensioner commonly used in belt systems as a tension applying mechanism is activated, and is about 200 to 400 N when the belt width is 20 mm. If the tension when installed is less than 200 N, the belt transmission ability under high load is impaired, and there is a risk of problems such as tooth jumping occurring under high load. On the other hand, if the tension when installed is more than 400 N, the belt runs with an excessively high belt tension, which accelerates bending fatigue of the core wire or wear of the tooth cloth, and there is a risk of early deterioration of the durability of the belt.

[0075] For example, in the engine assembly process, when a toothed belt with a belt width of 20 mm is attached by hand (without tools) to a two-shaft layout with a fixed shaft distance, consisting of one drive pulley and one driven pulley, the upper limit of the tension level during installation that can be attached by hand (without tools) is at most about 100 N.

[0076] (How to use toothed pulley 1 as a belt mounting pulley) (1) First, the rotating shaft of the toothed pulley 1 (drive pulley 101) and the rotating shaft of the driven pulley 102 are fixed in distance (pulley layout with fixed distance between the axes) so that the pulley layout circumference (L2) after the belt is installed is longer (for example, about 0.05 to 0.1% longer) than the belt reference circumference (L0) according to the required level of tension when the belt is installed (for example, about 200 to 400 N).

[0077] (2) The driven pulley 102 is connected to the rotating shaft. Next, the base member 11 to which the first split pulley 12 is attached (alternatively, the first split pulley 12 may be formed integrally with the base member 11) is connected to the rotating shaft of the toothed pulley 1 (drive pulley 101). That is, the toothed pulley 1 in a state in which the second split pulley 13 is not attached to the base member 11 is connected to the rotating shaft of the toothed pulley 1 (drive pulley 101) as a belt attachment pulley used when attaching the toothed belt 2 between the toothed pulley 1 (drive pulley 101) and the driven pulley 102.

[0078] 9, the toothed pulley 1 as the belt mounting pulley is rotated so that the arc portion 12d connecting the outer edges of the groove portion 14 formed on the outer periphery of the first split pulley 12 remains within the inner region of the circumference of the pulley layout including the toothed pulley 1 as the belt mounting pulley (a line formed in a circular shape along the outer periphery of the toothed pulley 1 as the belt mounting pulley and the driven pulley 102 so as to connect the outer periphery of the toothed pulley 1 as the belt mounting pulley and the driven pulley 102). By making such a pulley layout, the circumference (L1) of the pulley layout before the belt is mounted can be made shorter in advance than the belt reference circumference (L0) (preparation step: FIG. 9).

[0079] (3) Next, the toothed belt 2 is wound between the toothed pulley 1 serving as a belt mounting pulley and the driven pulley 102. This makes it possible to easily suspend the toothed belt 2, which has a relatively high belt elasticity, around a pulley layout including the toothed pulley 1 serving as a belt mounting pulley (suspending step: FIG. 10).

[0080] (4) Next, as shown in FIG. 11, the toothed pulley 1 as the belt installation pulley is rotated by using the principle of leverage as necessary (for example, by connecting an L-shaped jig such as a hexagonal wrench to the end of the rotation shaft of the toothed pulley 1). Specifically, as shown in FIG. 12, the toothed pulley 1 as the belt installation pulley is rotated half a turn, that is, the toothed pulley 1 as the belt installation pulley is rotated to a position where the arc portion 12d of the first divided pulley 12 substantially overlaps with the pulley layout circumference as viewed in the rotation shaft direction, so that the pulley layout circumference (L2) after the belt installation can be made longer (for example, about 0.05 to 0.1% longer) than the belt reference circumference (L0). Therefore, the toothed pulley 1 as the belt installation pulley functions as a tension applying mechanism when the toothed belt 2 is installed between the toothed pulley 1 (drive pulley 101) and the driven pulley 102 (tension applying step: FIG. 11, FIG. 12).

[0081] (5) Finally, as shown in Fig. 13, while the second split pulley 13 is placed against the boss portion 111 and the first split pulley 12, the convex portion 13c of the second split pulley 13 is fitted into the concave portion 113 of the flange 112 along a direction parallel to the rotation axis, and the second split pulley 13 and the flange 112 are fastened together with rivets or screws, thereby attaching the second split pulley 13 to the outer periphery of the boss portion 111 via the base member 11. That is, the toothed pulley 1 is formed by integrating the base member 11, the first split pulley 12, and the second split pulley 13. As a result, the toothed pulley 1, which has exactly the same external shape (annular shape) and function as a normal toothed pulley, can be applied to the synchronous power transmission belt system 100 as the drive pulley 101 (assembly step: Fig. 13).

[0082] According to the above configuration, even when a toothed belt 2 having a relatively high belt elasticity is attached to a pulley layout that does not have a conventional tensioning mechanism (such as a shift in the axis distance, a tension pulley, or a tensioner), the tension of the toothed belt 2 when attached can be set to a relatively high level.

[0083] (Other embodiments) (1) In the above embodiment, the first split pulley 12 and the base member 11 are configured to be attachable as separate members, but the first split pulley 12 and the base member 11 may be integrated into one member (belt attachment pulley in the state shown in FIG. 5). That is, with the first split pulley 12 fixed to the outer periphery of the boss portion 111, the first split pulley 12, the boss portion 111, and the flange 112 may be formed as a single solid unit (non-disassembleable), and the second split pulley 13 may be fixed thereto via rivets or screw members.

[0084] (2) In the above embodiment, the flange 112 is provided on only one side of the toothed pulley 1, but it may be provided on the other side. For example, in the first split pulley 12 and the second split pulley 13, a flange extending at least to the outer edge of the groove portion 14 may be formed on the side opposite to the side facing the flange 112. That is, the toothed pulley 1 may have a configuration having the flange 112 only on one side (pulley with one flange), or may have a configuration in which the flange 112 is provided in addition to the flange 112 provided on the base member 11 (pulley with two flanges). In the latter configuration (pulley with two flanges), it is possible to reliably prevent the toothed belt 2 from falling off the toothed pulley 1.

[0085] (3) In the above embodiment, the central angle α (α = 180°) of the arc portion 12d of the first split pulley 12, as viewed in the direction of the rotation axis, is approximately the same as the winding angle of the toothed belt 2 around the toothed pulley 1 (hereinafter simply referred to as the winding angle), and the central angle α of the arc portion 12d, as viewed in the direction of the rotation axis, is set in such a manner that the arc portion 12d remains in the inner region of the circumference of the pulley layout including the toothed pulley 1 as a belt mounting pulley, and the circumferential length (L1) of the pulley layout is made shorter than the belt reference circumference (L0) of the toothed belt 2.

[0086] As an embodiment of the present invention, as shown in FIG. 14(A), the central angle α of the arc portion 12d of the first split pulley 12 may be set to be less than the winding angle. In this case, from the viewpoint of improving the assembling workability of the remaining split pulleys (facilitating the work in the assembling step), it is preferable that the remaining second split pulley 13 is further divided into a plurality of parts (2 to 3) (see FIG. 15(E)) (in FIG. 14 and FIG. 15, the second split pulley 13 is further divided into a second split pulley 131 and a second split pulley 132). Furthermore, it is preferable to apply the toothed pulley 1 to a pulley layout in which the groove portion 14 of the toothed pulley 1 has a shape corresponding to a straight tooth, and the distance (span length) between the toothed pulley 1 (drive pulley 101) and the driven pulley 102 via the toothed pulley 1 is relatively long. Furthermore, it is preferable to apply the toothed pulley 1 (drive pulley 101) to a synchronous power transmission belt system in which the winding angle is smaller than 180° (for example, a two-axis layout in which the diameter of the driven pulley 102 is larger than the diameter of the drive pulley 101).

[0087] However, from the viewpoint of improving the ease of assembly of the second split pulley 13 (ease of assembly in the assembly step), it is preferable that the central angle α of the arc portion 12d of the first split pulley 12, as viewed in the direction of the rotation axis, is equal to or larger than the winding angle, and that the central angle α of the arc portion 12d, as viewed in the direction of the rotation axis, is within a range in which the circumferential length (L1) of the pulley layout is less than the belt reference circumferential length (L0) of the toothed belt 2 in a state in which the arc portion 12d is provided in a manner such that it remains in an inner region of the circumference of the pulley layout including the toothed pulley 1 as the belt mounting pulley. In this case, the present invention can also be applied to a synchronous power transmission belt system in which the winding angle of the toothed pulley 1 (drive pulley 101) is greater than 180° (for example, a two-axis layout in which the diameter of the driven pulley 102 is smaller than the diameter of the drive pulley 101).

[0088] In other words, from the viewpoint of achieving both the effect (magnitude) of being able to change the pulley layout circumference (L) before and after belt attachment and the ease of assembly of the remaining second split pulley 13 (ease of assembly in the assembly step), it is more preferable to set the central angle α of the arc portion 12d of the first split pulley 12 to be the same as the winding angle (above embodiment: Figure 13) or in a slightly larger angle range as shown in Figure 16 (A).

[0089] 14(A), when the central angle α of the arc portion 12d of the first split pulley 12 is set to be less than the winding angle, if there is only one remaining second split pulley 13 (not shown), in the assembly step, when the second split pulley 13 is placed against the boss portion 111 and the first split pulley 12 and the protruding portion 13c of the second split pulley 13 is fitted into the recessed portion 113 of the flange 112 along a direction parallel to the rotation axis, the toothed belt 2 must be pushed outward in the radial direction of the toothed pulley 1 against the tension of the toothed belt 2. This may hinder the assembly workability of the second split pulley 13 to the base member 11. Therefore, when the central angle α of the arc portion 12d of the first split pulley 12 is set to be less than the winding angle, in order to prevent the workability of assembling the second split pulley 13 to the base member 11 (workability in the assembling step) from being hindered, the remaining second split pulley 13 is further divided into a plurality of parts (2 to 3) (see FIG. 15(E)), and in the assembling step, the second split pulley 13 is brought into contact with the boss portion 111 and the first split pulley 12 at the same time. Furthermore, when fitting the convex portion 13c of the second split pulley 13 into the concave portion 113 of the flange 112 along a direction parallel to the rotation axis, it is not necessary to push the toothed belt 2 radially outward from the toothed pulley 1 against the tension of the toothed belt 2. It is therefore preferable to repeat the tensioning step and the assembly step in stages (for example, in two stages as shown in Figures 14(B) to 15(E)) for each rotation angle of the toothed pulley 1 used as a belt fastening pulley.

[0090] On the other hand, in this embodiment (see Figures 9 to 13) and as shown in Figure 16, when the central angle α of the arc portion 12d of the first split pulley 12 is set to be greater than or equal to the winding angle, as long as the central angle α of the arc portion 12d is set within a range in which the circumferential length (L1) of the pulley layout before the belt is attached is less than the belt reference circumferential length (L0) of the toothed belt 2, the assembly workability of the second split pulley 13 (workability in the assembly step) is not impaired, even if the remaining second split pulley 13 is not further divided into multiple parts (2 to 3).

[0091] (4) In the above embodiment, the toothed pulley 1 is used as the driving pulley 101, but the toothed pulley 1 may be applied to either the driving pulley 101 and / or the driven pulley 102 in the synchronous power transmission belt system 100. However, in the synchronous power transmission belt system 100 (pulley layout) having a plurality (two or more) pulleys, it is preferable that only one pulley is the toothed pulley 1. In this case, the manufacturing costs of the synchronous power transmission belt system 100 (particularly the pulley layout) and the effort of mounting the toothed belt 2 to the pulley layout can be kept to a minimum. EXAMPLES

[0092] In the toothed pulley of the present invention, even when a belt with a relatively high belt elasticity is installed in a pulley layout that does not have a conventional tensioning mechanism (axis distance movement, tension pulley, tensioner, etc.), it is necessary that the belt can be installed between the pulleys so that the tension of the belt when installed can be set to a relatively high level.

[0093] In this embodiment, toothed pulleys according to Examples 1 to 3 and Comparative Examples 1 and 2 (hereinafter, each specimen) were produced, and the tension when the belt was attached was measured and comparative verification was performed. Note that the present invention will be described in more detail below based on the examples, but the present invention is not limited to these examples.

[0094] [Toothed pulley] (Common to each specimen) The toothed pulleys in Example 1 (FIG. 2), Example 2 (FIG. 17), Example 3 (FIG. 18), and Comparative Examples 1 and 2 (FIG. 19) were all straight toothed pulleys with 30 teeth. -Material used: Iron alloy (nickel-iron alloy). Pulley manufacturing method: Manufactured by machining (cutting, etc.). Note that multiple (2 or 3) split pulleys were manufactured in one piece (without division) like normal toothed pulleys, and then cut into multiple split pulleys using wire-cut electric discharge machining.

[0095] (Examples 1 to 3: Figs. 1, 2, 17, and 18) (multiple split pulleys) Number of multiple split pulleys and central angle α of the circular arc portion: 2 in Example 1 (2 with α=180°), 3 in Example 2 (1 with α=84°, 1 with α=96°, 1 with α=180°), 2 in Example 3 (1 with α=84°, 1 with α=276°) The dividing surface is formed to extend along the radial direction of the toothed pulley. Each split pulley is split circumferentially at the bottom of the groove.

[0096] (Base member 11) The base member has a structure in which a boss portion and a circular flange extending radially outward from one side of the boss portion are integrally formed, and has fastening members (screw members) (not shown) that fasten each split pulley to the base member. In addition, the flange has multiple (8 places) through holes through which fastening members (bolts) can be inserted, and the side surface to which the base member of the split pulley is attached has multiple holes (2 to 6 places on each side) formed so that they can be hinged with fastening members (screw members). The flange extends from one side of the boss portion to at least the outer edge of the groove portion (more specifically, to a position where the entire side surface of the back portion of the toothed belt can abut). The split pulley and the base member are configured with a spigot structure (the convex portion on the split pulley side and the concave portion on the base member side can be concentrically fitted together).

[0097] (Some split pulleys) With the above configuration, of the multiple (two or three) split pulleys, one (a part) of the split pulleys (one piece) can be formed integrally with the base member (boss portion) (i.e., can be connected to the rotating shaft) when the other (remaining) split pulleys (one or two pieces) are not attached to the base member (the other (remaining) split pulleys are not attached to the outer circumferential portion of the boss portion).

[0098] (Comparative Examples 1-2: FIG. 19) The toothed pulleys of Comparative Examples 1 and 2 were normal toothed pulleys having a boss portion configured to be connectable to a rotating shaft and a groove portion formed on the outer circumferential side of the boss portion that meshes with the teeth of a toothed belt. The outer peripheral portion of the boss does not have a shape divided into multiple parts in the circumferential direction.

[0099] [Synchronous transmission belt system] (Common to each specimen) (Toothed belt: Fig. 8) Toothed belt designation: 105S8M20 Tooth shape: The tooth shape is an S-tooth profile (STPD type) belonging to straight teeth, and the tooth pitch is S8M, which is 8 mm (see Figure 8). Number of teeth: 105 Tooth pitch: 8mm Belt width: 20mm Belt reference circumference (L0): 839.37 mm (the belt tension applied at this time is approximately 100 N) -Belt elasticity: 285KN Calculation formula: (T-T0) / [(L-L0) / L0], (312N-98N) / [(840.00-839.37)mm / 839.37mm] =285KN

[0100] ·Materials used (Rubber-like elastic material constituting the back and teeth) Rubber component of rubber composition: Hydrogenated nitrile rubber (HNBR) Rubber composition ingredients: See Table 1

[0101] [Table 1]

[0102] (Tooth cloth) ·Configuration: See Table 2 -Tooth cloth thickness (thickness at belt cross section): 0.2 mm [Table 2]

[0103] (Core) ·Configuration: Table 3 [Table 3]

[0104] [Table 4]

[0105] The core wire (twisted cord) was created using the following steps: 600 filaments (7 microns in diameter) of high-strength glass fiber (K-glass fiber) designated KCE-225 as described in JIS R 3413 (2012) were bundled and aligned to form three strands. The three strands were immersed in an RFL liquid (18-23°C) having the composition shown in Table 4 by passing them through for 3 seconds, and then heated and dried at 200-280°C for 3 minutes to form a uniform adhesive layer on the surface. After this adhesion treatment, the three strands were first twisted with 12 twists / 10 cm, and 11 of these were aligned and twisted (top twisted) with 8 twists / 10 cm in the opposite direction to the first twist to prepare a twisted cord with a diameter of approximately 0.9 mm.

[0106] (Manufacturing method of toothed belt) First, the rubber composition shown in Table 1 was kneaded in a Banbury mixer, and the kneaded rubber was passed through a calendar roll to form a rolled rubber sheet of a specified thickness, to prepare an unvulcanized rubber sheet for forming the back part and teeth part of the toothed belt. The prepared rubber composition (unvulcanized rubber sheet) was press-vulcanized at 165°C for 30 minutes to obtain a vulcanized rubber sheet. The hardness of the vulcanized rubber sheet was approximately 70 in type A durometer hardness (JIS K6253:2012 compliant). Next, a woven fabric to be used as the tooth cloth having the composition shown in Table 2 was woven, and was then immersed in the RFL liquid shown in Table 4, dried, and heat-treated. After that, an adhesion treatment was performed in which the fabric was immersed in a rubber paste made by dissolving the same rubber composition as the unvulcanized rubber sheet shown in Table 1 in a solvent, and then dried. The above materials, that is, the core wire (adhesive treated), the tooth cloth (adhesive treated), and the rubber composition (unvulcanized rubber sheet), were used to manufacture toothed belts of the specified designation by the method described below. First, the fiber fabric forming the tooth cloth is wound around the outer periphery of a cylindrical mold having a plurality of grooves (concave stripes) corresponding to the teeth of the toothed belt. Next, a twisted cord constituting a core wire, having the composition and configuration shown in Table 3, is wound helically at a predetermined pitch (so as to have a predetermined pitch in the axial direction of the cylindrical mold) around the outer periphery of the wound fiber fabric. Furthermore, the unvulcanized rubber sheet forming the back portion and teeth is wound around the outer periphery to form an unvulcanized belt molding (unvulcanized laminate). Next, the unvulcanized belt molded body is placed on the outer periphery of a cylindrical mold, and a rubber jacket, which is a steam barrier material, is placed on the outside of the unvulcanized belt molded body. The jacketed belt molded body and the cylindrical mold are then placed inside a vulcanizing device such as a vulcanizing can. When the belt molded body is heated and pressurized inside the vulcanizing device, the rubber composition of the unvulcanized rubber sheet and the woven fiber fabric are pressed into the grooves (concave strips) of the cylindrical mold to form a toothed portion of a desired shape, and the rubber composition of the unvulcanized rubber sheet is vulcanized to form a sleeve-shaped vulcanized molded body (vulcanized belt sleeve) in which the rubber composition, the woven fiber fabric, and the core wire are integrated. At this time, the woven fiber fabric is stretched to a shape that follows the contour shape of the toothed portion, and becomes a tooth cloth placed on the surface of the toothed portion. The vulcanized belt sleeve removed from the cylindrical mold is then cut to a predetermined width to obtain a plurality of toothed belts of predetermined names.

[0107] (Pulley layout) The belt systems of Example 1 (FIG. 13), Example 2 (FIGS. 14, 15), Example 3 (FIG. 16), and Comparative Examples 1 and 2 (FIG. 20) all have a two-shaft layout with a fixed axis and do not have a conventional tensioning mechanism (axis distance movement, tension pulley, tensioner, etc.), and are equipped with an axis load detector (load cell) that can be connected to one of the rotating shafts (drive pulley). Number of teeth on drive pulley / pulley diameter (assuming core line): 30 teeth / 76.394 mm Number of teeth on driven pulley / pulley diameter (assuming core line): 30 teeth / 76.394 mm The toothed pulleys of Examples 1 to 3 (Fig. 2, Fig. 17, Fig. 18) and Comparative Examples 1 and 2 (Fig. 19) were all used as drive pulleys in the above layout. Whether the pulley used is a drive pulley or a driven pulley, there is no difference in the effect obtained, and it is considered that this problem can be solved.

[0108] (Example 1: FIG. 13) Required belt tension when fastened: Approximately 300N. Number of toothed pulleys with split pulleys: 1 (applied to driving pulley) When viewed in the direction of the central axis of the rotating shaft, the central angle α of the arc portion connecting the outer edges of the grooves in some of the split pulleys is 180°, which is the same as the winding angle (180°) of the toothed belt around the toothed pulley. -Circumference of pulley layout before belt installation (L1): 796.39 mm (The circumferential length of the pulley layout when the circular arc portion is disposed in the inner region of the circumference of the pulley layout including the toothed pulley when viewed in the direction of the rotation axis of the rotation shaft) Pulley layout circumference after belt installation (L2): 840.00mm

[0109] (Example 2: Figures 14 and 15) Required belt tension when fastened: Approximately 300N. Number of toothed pulleys with split pulleys: 1 (applied to driving pulley) When viewed in the direction of the central axis of the rotating shaft, the central angle α of the arc portion connecting the outer edges of the grooves in some of the split pulleys is 84°, which is smaller than the winding angle (180°) of the toothed belt around the toothed pulley. -Circumference of pulley layout before belt installation (L1): 740.21mm Pulley layout circumference after belt installation (L2): 840.00mm

[0110] (Example 3: FIG. 16) Required belt tension when fastened: Approximately 300N. Number of toothed pulleys with split pulleys: 1 (applied to driving pulley) When viewed in the direction of the central axis of the rotating shaft, the central angle α of the arc portion connecting the outer edges of the grooves in some of the split pulleys is 276°, which is larger than the winding angle (180°) of the toothed belt around the toothed pulley. -Circumference of pulley layout before belt installation (L1): 835.12mm Pulley layout circumference after belt installation (L2): 840.00mm

[0111] (Operation: Examples 1 to 3) (1) In advance, in a pulley layout in which the toothed pulley of the above embodiment was used as a drive pulley, the distance between the two pulleys (two shafts) was fixed (shaft distance 300.00 mm) so that the pulley layout circumference (L2) after the belt was installed (the belt circumference after going through specified steps and applying the installation tension) would be 840.00 mm, which is 0.63 mm (0.075%) longer than the belt reference circumference (L0: 839.37 mm), in accordance with the required level of belt installation tension (approximately 300 N).

[0112] (2) Preparation Step (Example 1: FIG. 9, Example 2: FIG. 14(A), Example 3: FIG. 16(A)) One (a part) of the split pulleys, configured to be connectable to the rotating shaft, is connected to the rotating shaft of the drive pulley via a fixing means (base member) as a belt mounting pulley used when mounting a toothed belt between pulleys when the other (remaining) split pulley is not attached to the outer circumferential portion of the boss portion, and the pulley layout is arranged in such a way that, when viewed in the central axial direction of the rotating shaft, the arc portion connecting the outer edges of the groove portions in one (a part) of the split pulleys remains within the inner region of the circumference of the pulley layout including the toothed pulley (a line formed in a ring shape along the outer periphery of each pulley to connect the outer peripheries of each pulley). As a result, the circumferential length (L1) of the pulley layout before the belt is attached is shorter than the belt reference circumferential length (L0: 839.37 mm) in Example 1, 740.21 mm in Example 2, and 835.12 mm in Example 3.

[0113] (3) Suspension step (FIG. 10 for Example 1, not shown for Examples 2 and 3) Therefore, a toothed belt with a relatively high level of belt elasticity (285KN) could be easily suspended on the pulley layout.

[0114] (4) Tensioning step (Example 1: FIGS. 11 and 12; Example 2: FIGS. 14(B) and 15(D); Example 3: not shown) (Examples 1 and 3) Using the principle of leverage (connecting a hexagonal wrench to the end of the rotating shaft of one of the split pulleys), the belt mounting pulley (a pulley whose outer peripheral portion of the boss is composed only of one of the split pulleys) was rotated half a turn, that is, to a position where the arc portion approximately overlaps with the pulley layout circumference when viewed in the direction of the central axis of the rotating shaft, so that the pulley layout circumference after belt mounting (L2) was 840.00 mm, which is 0.63 mm (0.075%) longer than the belt reference circumference (L0: 839.37 mm), and the belt was mounted between the pulleys while applying tension to the suspended toothed belt.

[0115] Example 2 As described in detail below, the tensioning step and the assembly step described below were repeated in two steps. That is, first, using the principle of leverage (connecting a hexagonal wrench to the end of the rotating shaft of the portion of the split pulley), the belt mounting pulley [a pulley whose outer peripheral portion of the boss portion is composed only of a portion of the split pulley (central angle α of the arc portion: 84°)] was rotated approximately 132°, that is, to a position where, when viewed in the central axial direction of the rotating shaft, the arc portion approximately overlaps with the pulley layout circumference, and where, in the assembly step, the toothed belt does not have to be pushed radially outward from the toothed pulley against the tension of the toothed belt, thereby applying a first stage of tension to the suspended toothed belt (see Figure 14(B)). In this state, part of the assembly step described below was performed (connecting the first of the remaining split pulleys (2 split) (the one with a central angle α of the arc portion of 96°) to the rotating shaft of the belt mounting pulley) (see Figure 14(C)). Furthermore, using the principle of leverage, the belt mounting pulley was rotated approximately 96°, that is, to a position where the toothed belt does not need to be pushed radially outward from the toothed pulley against the tension of the toothed belt in the assembly step, and finally, the pulley layout circumference (L2) after the belt is mounted is set to 840.00 mm, which is 0.63 mm (0.075%) longer than the belt reference circumference (L0: 839.37 mm), and the belt is mounted between the pulleys while applying a final mounting tension to the suspended toothed belt (see Figure 15 (D)). In this state, the remaining work in the assembly step [connecting the remaining split pulley (the one with a central angle α of the arc portion of 180°) to the rotating shaft of the belt mounting pulley] was carried out (see Figure 15 (E)).

[0116] (5) Assembly steps (Fig. 13, Fig. 14(C), Fig. 15(E), Fig. 16(B)) Finally, the other (remaining) split pulley is connected to the rotating shaft of the belt mounting pulley via a fixing means, thereby forming one (part) of the split pulley and the other (remaining) split pulley into a circular ring shape, resulting in a toothed pulley having the same appearance, shape and function as a normal toothed pulley.

[0117] (Comparative Examples 1 and 2: FIG. 20) (Comparative Example 1: FIG. 20(A)) Pulley layout circumference (L): 839.37mm (fixed) (Comparative Example 2: FIG. 20(B)) Pulley layout circumference (L): 840.00mm (fixed)

[0118] (Operation: Comparative Examples 1 and 2) Comparative Example 1 (1) In advance, in a pulley layout in which the toothed pulley of Comparative Example 1 was used as a drive pulley, the distance between the two pulleys (two shafts) was fixed (axis distance 299.69 mm) so that the pulley layout circumference (L) (fixed) was the same length as the belt reference circumference (L0: 839.37 mm).

[0119] (2) For the pulley layout in question (a pulley layout in which the circumference of the pulley is the same as the reference circumference of the belt), the toothed belt was suspended by hand (without any tools) and installed between the pulleys.

[0120] Comparative Example 2 (1) In advance, in a pulley layout in which the toothed pulley of Comparative Example 2 was used as the drive pulley, the distance between the two pulleys (two shafts) was fixed (axis distance 300.00 mm) so that the pulley layout circumference (L) (fixed) was slightly longer (840.00 mm) than the belt reference circumference (L0: 839.37 mm).

[0121] (2) For the pulley layout in question (where the pulley layout circumference is slightly longer than the belt reference circumference), the toothed belt was suspended by hand (without any tools) and installed between the pulleys.

[0122] [Evaluation of toothed pulleys: items, methods and standards] For each test specimen (Examples 1 to 3, Comparative Examples 1 and 2), the belt fitting property and the tension when the belt was fitted were examined to determine whether a toothed pulley capable of solving the problem of the present application was obtained.

[0123] [Belt fit] (Method, criteria) If a toothed belt with a relatively high level of elasticity (for example, about 200 to 400 kN) can be suspended by hand (with a force of about 100 N, without any jigs or tools) over the pulley layout and installed between the pulleys, the belt's installation is evaluated as good (no problems in practical use) and given an A rating. If a toothed belt with a relatively high level of elasticity (for example, about 200 to 400 kN) could not be suspended by hand (with a force of about 100 N, without any tools) over the pulley layout and installed between the pulleys, the belt was evaluated as not being suitable for installation and given a grade of b. From the viewpoint of suitability for practical use in this application (ease of wearing the belt), a toothed pulley rated "A" was determined to be at the pass level.

[0124] [Belt tension when worn] (method) The tension of the belt when it was worn was calculated from the shaft load detected by a shaft load detector (load cell) connected to the rotating shaft of one side (the driving pulley).

[0125] (Judgment criteria) When the tension (initial tension) of a toothed belt having a relatively high belt elasticity (eg, about 200 to 400 KN) during installation could be set to a relatively high level (eg, about 200 to 400 N), the belt was rated as "a." A case where the tension (initial tension) at the time of installation of a toothed belt, in which the belt elasticity is at a relatively high level (for example, about 200 to 400 KN), could not be set to a relatively high level (for example, about 200 to 400 N) was rated as b. From the viewpoint of suitability for practical use in this application (tension when belt is attached), a toothed pulley rated "A" was determined to be at the pass level.

[0126] [Overall Judgment] The overall criteria for judging (ranking) whether a toothed pulley can solve this problem were determined as follows, based on the results of the two test items mentioned above (belt wearability, belt tension when worn). Rank A: If the above evaluations (belt wearability, belt tension when worn) were all rated A, the product was deemed to be a fully satisfactory solution to the problem (passed). Rank B: If even one of the above evaluations (belt wearability, belt tension when worn) was rated as B, the solution to this issue was deemed insufficient (failed).

[0127] [Verification results] The verification results are shown in Table 5. [Table 5]

[0128] (Effects obtained) From the above verification results, when the toothed pulleys of Examples 1 to 3 are applied to a pulley layout that does not have a conventional tensioning mechanism (such as a moving center distance, tension pulley, or tensioner), the circumferential length of the pulley layout before the belt is attached (L1: 796.39 mm in Example 1, 742.83 mm in Example 2, and 834.02 mm in Example 3) can be made shorter than the belt reference circumferential length (L0: 839.37 mm). Therefore, the belt elasticity is at a relatively high level (L1: 796.39 mm in Example 1, 742.83 mm in Example 2, and 834.02 mm in Example 3) in the pulley layout before the belt is attached. It was found that the belt can be installed between the pulleys while raising the tension applied to the belt when installed to a significantly higher level (312N in Examples 1 to 3) than the conventional level (98N in Comparative Example 1) where almost no tension was applied to the belt when installed. This suggests that the belt can be used in applications with higher loads. [Explanation of symbols]

[0129] 1 Toothed pulley 11 Base material 111 Boss section 112 Flange 12 First split pulley 13 Second split pulley 14 Groove 2 Toothed belt 100 Synchronous Transmission Belt System

Claims

1. A toothed pulley having a groove formed on its outer periphery to mesh with the teeth of a toothed belt, A boss portion connectable to a rotating shaft; A plurality of split pulleys attached to an outer circumferential side of the boss portion and having a shape divided into a plurality of pulleys in a circumferential direction of the boss portion; A fixing means for fixing a positional relationship of the plurality of split pulleys in the rotation axis direction; Equipped with Among the plurality of split pulleys, some of the split pulleys are attachable to or integrated with the outer circumferential side of the boss portion while the remaining split pulleys are not attached to the outer circumferential side of the boss portion, A toothed pulley, wherein the split pulley has a convex convex portion formed on one side, and the fixing means has a concave recess formed on one side, and the convex portion and the recess are concentrically fitted together.

2. 2. The toothed pulley according to claim 1, wherein the number of said plurality of split pulleys is two.

3. The toothed pulley according to claim 1 , wherein the groove portion has a shape extending in the direction of the rotation axis.

4. The fixing means is configured such that the boss portion and a flange portion extending radially outward from one side of the boss portion are integrally formed, The toothed pulley according to claim 1 , further comprising a fastening member for fastening said plurality of split pulleys and said flange portion together.

5. 5. The toothed pulley according to claim 4, wherein the flange portion extends from one side of the boss portion to at least an outer edge of the groove portion.

6. 2. The toothed pulley according to claim 1, wherein the plurality of split pulley members are circumferentially split at a bottom surface of the groove.

7. A synchronous power transmission belt system including a toothed belt having a plurality of teeth arranged at predetermined intervals along a belt longitudinal direction, and a pulley layout including two or more toothed pulleys arranged apart from each other, to which the toothed belt is attached, At least one of the two or more toothed pulleys is a toothed pulley according to any one of claims 1 to 6, the part of the split pulleys functions as a belt mounting pulley used when mounting the toothed belt to the pulley layout in a state in which the remaining split pulleys are not mounted to the outer periphery side of the boss portion and are mounted or integrated with the outer periphery side of the boss portion, a synchronous transmission belt system configured so that, before the toothed belt is attached to the pulley layout, an arc portion connecting the outer edges of the groove portions formed on the outer periphery of some of the split pulleys, when viewed in the direction of the rotation axis, remains in an inner region of the circumference of the pulley layout including the toothed pulley.

8. 8. The synchronous power transmission belt system according to claim 7, wherein only one of the two or more toothed pulleys is a toothed pulley according to any one of claims 1 to 6.

9. 8. The synchronous power transmission belt system according to claim 7, wherein a central angle of the arc portion, as viewed in the direction of the rotation axis, is equal to or greater than a winding angle of the toothed belt about the toothed pulley, and the central angle of the arc portion, as viewed in the direction of the rotation axis, is within a range such that a circumferential length of the pulley layout is less than a reference belt circumferential length of the toothed belt when the arc portion is provided in a manner such that it remains in the inner region of a circumference of the pulley layout including the toothed pulley.

10. A method for mounting the toothed belt to the pulley layout in the synchronous power transmission belt system of claim 7, comprising: a preparation step of connecting the boss portion to a rotation shaft, and arranging the pulley layout in such a manner that, as viewed in the direction of the rotation shaft of the split pulley, which is attached to the outer periphery of the boss portion or integrated with the outer periphery of the boss portion, an arc portion connecting the outer edges of the groove portion formed on the outer periphery of the split pulley remains within an inner region of the circumference of the pulley layout including the toothed pulley; a suspension step of suspending the toothed belt around the pulley layout provided in the preparation step; a tension applying step of rotating the toothed pulley including the part of the split pulleys to apply tension during installation to the toothed belt; and an assembling step of attaching the remaining split pulleys to the outer periphery of the boss portion via the fixing means.

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