Pully for toothed belt

Abstract

To provide a pully for a toothed belt capable of making productivity satisfactory in the pulley for a toothed belt in which teeth engage in a gap between two adjacent rollers.SOLUTION: In a pulley 1 for a toothed belt including an annular unit 2 around which a toothed belt 4 is wound and fixing means 3 for fixing the annular unit 2 to a rotating shaft S, the annular unit 2 includes: a cage 21 including a set of annular parts 211, 212, and a plurality of columns 213 for connecting a space between the set of annular parts 211, 212 to be arranged in a circumferential direction X at prescribed intervals to undergo form processing of outer diameter side barring parts 213A, 213B formed on an outer diameter side and an inner diameter side barring part 213C formed on an inner diameter side; and a plurality of column-shaped rollers 22 respectively held by a pocket 23 surrounded with a space between the outer diameter side barring parts 213A, 213B of mutually facing column parts 213 and a space between the inner diameter side barring parts 213C of mutually facing column parts 213 and the set of annular parts 211, 212 in a loosely fitted state.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pulley for a toothed belt around which a toothed belt is wound.

Background Art

[0002] Conventionally, a power transmission device including a drive pulley connected to a drive shaft, a driven pulley, and a toothed belt wound between the drive pulley and the driven pulley is known. On the inner peripheral surface of the toothed belt, convex belt tooth portions are formed at a predetermined pitch along the longitudinal direction of the belt. In addition, generally, a timing pulley is used for the pulleys used for the drive pulley and the driven pulley, and pulley groove portions that mesh with the belt tooth portions of the toothed belt are formed on the outer peripheral surfaces of the drive pulley and the driven pulley. The pulley groove portions are formed in a substantially similar shape to the belt tooth portions so as to mesh smoothly with the belt tooth portions.

[0003] In this regard, Patent Document 1 discloses a pulley for a toothed belt in which a groove portion (gap) formed on the outer peripheral portion of the drive pulley and meshing with the tooth portion of the toothed belt is formed by a part of the groove bottom surface that is arranged so as to surround two pin portions and the rotation center Cr of the drive pulley and does not contact the tooth portion of the toothed belt. According to this configuration, in the drive pulley, compared with the conventional configuration in which the pulley groove portion and the belt tooth portion of the drive pulley are substantially similar in shape and the meshing is in a surface contact state (the contact area is large), while making the pulley groove portion and the belt tooth portion mesh smoothly in the driving state (while minimizing the increase in contact surface pressure), by making the meshing between the pulley groove portion and the belt tooth portion in a line contact state (the contact area is small), the friction noise (screeching noise) itself during meshing can be reduced, and the groove bottom surface does not contact the belt tooth portion, and at least a part (for example, between the pin and the groove bottom surface of the pulley groove portion) is open to the outside, so that bursting noise and knocking noise can also be suppressed.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-048924 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] However, the pulley for a toothed belt in Patent Document 1 has a large number of parts. In particular, the number of pin parts is required corresponding to the number of a plurality of groove parts (pulley groove parts), and these plurality of pin parts must be arranged between a base part and a cover part facing each other in the rotational axis direction of the pulley for a toothed belt (specifically, one end of each pin part must be inserted into an insertion hole formed in the base part, and the other end of each pin part must be inserted into an insertion hole formed in the cover part). Therefore, in manufacturing the pulley for a toothed belt, in the assembly process of each part, a large amount of time, labor, and cost are required, and there has been a problem that productivity deteriorates significantly compared to the case of a normal pulley for a toothed belt (a machined product).

[0006] In this regard, a cage-roller assembly composed of a plurality of rollers and a retainer has been conventionally widely used as a functional unit of a roller bearing (rolling bearing) further including at least one raceway ring (an outer ring and / or an inner ring arranged concentrically) on which the rollers roll. That is, the cage-roller assembly has been widely used as a functional unit of a bearing that is a medium for operating the inner and outer members of the cage-roller assembly to be rotatable relative to each other.

[0007] Therefore, the idea came to use the cage-roller assembly not simply as a functional unit of a bearing, but as a functional unit of a toothed-belt pulley (power transmission member) that transmits power from one of the inner and outer members to the other. That is, by using the cage-roller assembly itself, which is composed of a plurality of rollers and a cage, as an annular unit of a toothed-belt pulley (using it in such a way that the belt teeth of the toothed belt engage with the gaps between two adjacent (opposite) rollers), it was found that manufacturing is easier, that is, productivity (especially productivity in the assembly process) is improved, compared to the case of the toothed-belt pulley of Patent Document 1.

[0008] An object of the present invention is to provide a toothed-belt pulley in which teeth engage with the gaps between two adjacent (opposite) rollers, and which can achieve good productivity.

Means for Solving the Problems

[0009] In order to solve the above problems, the present invention provides a toothed-belt pulley including an annular unit around which a toothed belt is wound, and fixing means for fixing the annular unit to a rotating shaft, wherein the annular unit includes a cage having a pair of annular portions and a plurality of columns that connect between the pair of annular portions, are arranged at a predetermined interval in the circumferential direction, and in which an outer-diameter-side anti-loosening portion formed on the outer-diameter side and an inner-diameter-side anti-loosening portion formed on the inner-diameter side are formed by foam processing, and a plurality of cylindrical rollers that are respectively held in a loosely fitted state in pockets surrounded by the outer-diameter-side anti-loosening portions between the columns facing each other, the inner-diameter-side anti-loosening portions between the columns facing each other, and the pair of annular portions.

[0010] According to the above configuration, a bearing unit that is generally used as a roller bearing (rolling bearing) further including at least one raceway ring (an outer ring and / or an inner ring arranged concentrically) on which the rollers roll can be diverted as an annular unit of a toothed-belt pulley. Therefore, unlike the structure of the pulley for toothed belt of Patent Document 1, it is not necessary to arrange a plurality of pin portions (corresponding to rollers) between a base portion and a cover portion facing each other in the rotational axis direction of the pulley for toothed belt (specifically, one end of each pin portion must be inserted into an insertion hole formed in the base portion, and the other end of each pin portion must be inserted into an insertion hole formed in the cover portion), and the production of the pulley for toothed belt is easy, that is, the productivity (especially the productivity in the assembly process) can be improved.

[0011] Further, the present invention provides the above pulley for toothed belt, wherein the fixing means has an annular base body facing the plurality of rollers, and the plurality of rollers and the base body may be arranged so as to be in contact with each other.

[0012] According to the above configuration, when a toothed belt is wound around the annular unit and a load by the toothed belt is applied to each roller, the roller and the base body come into contact with each other, so that the load can be released to the base body, and the load on the annular unit including the roller can be reduced.

[0013] Further, the present invention provides the above pulley for toothed belt, wherein the base body may be arranged on the inner diameter side of the annular unit so that no gap is formed between each roller and the inner diameter side anti-loosening portion when each roller and the base body come into contact with each other.

[0014] According to the above configuration, there is no gap (separation distance) between the roller and the inner diameter side anti-loosening portion, and the roller can be held between the outer diameter side anti-loosening portion and the inner diameter side anti-loosening portion (or the base body) so that the radial play allowance of the roller is maximized (the roller can be held in the most loosely fitted state). Thereby, each roller can be brought into contact (inscribed) with the base body at the most inner peripheral side position, the radial movement distance of each roller can be maximized, and foreign matter that has entered between each roller and the base body can be easily discharged.

[0015] In addition, the present invention provides a pulley for a toothed belt, wherein the base body is arranged on the inner diameter side of the annular unit such that each roller is sandwiched between the outer diameter side anti-loosening portions facing each other and the base body. This may be a characteristic feature.

[0016] According to the above configuration, the play allowance of the rollers in the radial direction can be set to 0 (zero). Therefore, each time the teeth of the toothed belt engage and disengage with the spaces (pulley groove portions) between the rollers, it is possible to prevent the generation of abnormal noise (rattling sound) caused by the rollers moving radially and contacting the retainer (column portion). Furthermore, the depth of the pulley groove portion and the pitch between two adjacent rollers can be maximized. As a result, the degree of freedom in designing the teeth (shape and dimensions) of the toothed belt that meshes with the pulley groove portion can be increased, and the meshing performance between the pulley groove portion of the toothed belt pulley and the teeth of the toothed belt can be made optimal. Moreover, a certain distance (separation distance) can be ensured between the roller and the inner diameter side anti-loosening portion. Therefore, the effect of discharging foreign matter from the bottom of the pulley groove portion to the outside and reducing noise (not only frictional noise but also cracking sound and knocking sound) can be obtained.

[0017] In addition, the present invention provides a pulley for a toothed belt, wherein the fixing means further includes a cover body, the base body is formed to cover at least a part of the inner circumference, one side surface, and the outer circumference of the annular unit, and is connectable to the rotating shaft, the cover body is formed to cover at least a part of the other side surface and the outer circumference of the annular unit, and is fixable to the base body, the inner width in the direction of the rotating shaft between the portion of the base body covering one side surface of the annular unit and the portion of the cover body covering the other side surface of the annular unit is smaller than the outer width of the annular unit in the direction of the rotating shaft. The annular unit may be sandwiched between the base body and the cover body in a compressed state in the axial direction of the rotation axis.

[0018] By sandwiching the annular unit between the base body and the cover body that are divided in the axial direction of the rotation axis as described above and enabling the base body and the cover body to be fixed, the annular unit and the fixing means (base body and cover body) can be integrated. Thereby, the annular unit can be easily fixed to the rotation axis. Also, the inner width in the axial direction of the rotation axis between the portion of the base body that covers one side surface of the annular unit and the portion of the cover body that covers the other side surface of the annular unit is formed to be smaller than the outer width in the axial direction of the rotation axis of the annular unit. Since the annular unit is sandwiched between the base body and the cover body in a compressed state in the axial direction of the rotation axis, the annular unit can be fixed between the base body and the cover body. Thereby, the annular unit and the fixing means (base body and cover body) can be fixed so as not to be relatively rotatable (without slipping). According to the above configuration, when the toothed belt pulley is used as a driving pulley, power can be reliably transmitted from the rotation axis to the base body, the cover body, the annular unit, and via the roller to the toothed belt. Also, when the toothed belt pulley is used as a driven pulley, power can be reliably transmitted from the toothed belt, via the roller, the annular unit, the base body, and the cover body to the rotation axis.

[0019] Further, the present invention relates to the toothed belt pulley described above, The base body and the cover body may be characterized in that a concave portion formed on one side and a convex portion formed on the other side are fitted concentrically.

[0020] According to the above configuration, the base body and the cover body can be accurately arranged concentrically.

[0021] Further, the present invention relates to the toothed belt pulley described above, The base body is formed with a base body side flange portion extending radially outward. The cover body is formed with a cover body side flange portion extending radially outward. The distance between the base body side flange portion and the cover body side flange portion may be characterized in that it is larger than the width of the toothed belt.

[0022] According to the above configuration, by guiding the toothed belt between the base body side flange portion and the cover body side flange portion, the toothed belt can be wound around the outer periphery of the annular unit in the width direction without lateral displacement.

Effect of the Invention

[0023] According to the present invention, it is possible to provide a toothed belt pulley in which teeth engage with gaps between two adjacent (opposite) rollers, and which can improve productivity.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Mode for Carrying Out the Invention

[0025] (Embodiment 1) Hereinafter, the toothed belt pulley 1 according to Embodiment 1 of the present invention will be described with reference to the drawings. In the following description, the circumferential direction X is the pulley circumferential direction and is the direction along the outer periphery of the toothed belt pulley 1. The radial direction is the pulley radial direction and is the direction along the radius from the center of the toothed belt pulley 1. The width direction is the rotation axis direction and is the direction parallel to the rotation axis S that is the center of rotation of the toothed belt pulley 1.

[0026] (Structure of the toothed belt pulley 1) The pulley 1 for a toothed belt according to Embodiment 1 is used, for example, in a power transmission device. Specifically, in a power transmission device including a toothed belt 4 wound between a driving pulley connected to a rotating shaft S serving as a driving shaft and a driven pulley (not shown) to which power is to be transmitted, the pulley 1 for a toothed belt is used as a driving pulley or a driven pulley (in Embodiment 1, the pulley 1 for a toothed belt is used as a driving pulley). The rotation of the rotating shaft S serving as a driving shaft is transmitted from the driving pulley (the pulley 1 for a toothed belt) to the driven pulley via the toothed belt 4.

[0027] As shown in FIG. 1, the pulley 1 for a toothed belt includes an annular unit 2 around which the toothed belt 4 is wound, and fixing means 3 for fixing the annular unit 2 to the rotating shaft S.

[0028] (Annular unit 2) As shown in FIGS. 4 to 6, the annular unit 2 includes a retainer 21 having a pair of annular portions 211 and 212 and a plurality of column portions 213 that connect between the annular portion 211 and the annular portion 212 and are arranged at a predetermined interval in the circumferential direction X, and a plurality of cylindrical rollers 22.

[0029] The retainer 21 has outer diameter side anti-loosening portions 213A and 213B (see FIG. 5(A)) formed at both ends in the rotation axis direction on the outer diameter side of the annular unit 2, and an inner diameter side anti-loosening portion 213C (see FIG. 5(A)) formed on the inner diameter side of the annular unit 2 between the outer diameter side anti-loosening portion 213A and the outer diameter side anti-loosening portion 213B, and the outer diameter side anti-loosening portions 213A and 213B and the inner diameter side anti-loosening portion 213C are formed by foam processing.

[0030] Here, in the two adjacent column portions 213 of the cage 21, the distance between the outer diameter side anti-loosening portions 213A facing each other (the separation distance in the circumferential direction X), the distance between the outer diameter side anti-loosening portions 213B facing each other (the separation distance in the circumferential direction X), and the distance between the inner diameter side anti-loosening portions 213C facing each other (the separation distance in the circumferential direction X) are formed to be smaller than the outer diameter (the width in the circumferential direction X) of the roller 22 by the fitting allowance.

[0031] The rollers 22 are respectively held in a loosely fitting state in pockets 23 surrounded by between the outer diameter side anti-loosening portions 213A facing each other and the outer diameter side anti-loosening portions 213A, between the outer diameter side anti-loosening portions 213B facing each other and the outer diameter side anti-loosening portions 213B, between the inner diameter side anti-loosening portions 213C facing each other, and a pair of annular portions 211 and 212 (the pair of annular portions 211 and 212 cover both end faces of the roller 22) in the two adjacent column portions 213 (see FIGS. 6(B) and 6(C)). For example, the cage 21 holds the rollers 22 in a state where there is a play of about 1 mm in the radial direction between the outer diameter side anti-loosening portions 213A and 213B and the inner diameter side anti-loosening portion 213C. With the above configuration, the rollers 22 are not dropped from the pockets 23 of the cage 21 and are held in a loosely fitting state. Thus, by holding the rollers 22 in a loosely fitting state in the pockets 23 of the cage 21, it is possible to easily discharge foreign matter that has entered between each roller 22 and the base body 31.

[0032] Further, the annular unit 2 is provided with pulley groove portions 24 formed between two adjacent rollers 22 and on the outer diameter side of the inner diameter side anti-loosening portion 213C (see FIG. 5(A)). That is, in the annular unit 2, a plurality of pulley groove portions 24 are formed at predetermined intervals in the circumferential direction X. The toothed belt 4 is wound around the toothed belt pulley 1 by engaging the teeth of the toothed belt 4 with the plurality of pulley groove portions 24 formed in the annular unit 2. Note that the tooth portion of the toothed belt 4 and the inner diameter side anti-loosening portion 213C may be designed in a non-contact manner as shown in FIGS. 2(A) and 3(C), or may be designed in a contact manner as shown in FIGS. 16(A) and (C).

[0033] As the above-described annular unit 2, a "cage-roller assembly" (general-purpose product) composed of rollers and a cage of a metal roller bearing (needle bearing) can be used. Specifically, a cage-roller assembly in which the cage is of a single-row M type can be used. For example, general-purpose products such as the FWF series manufactured by NSK Ltd., the KMJ series manufactured by NTN Corporation, the K series manufactured by Schaeffler Japan Co., Ltd., the KT series manufactured by Nippon Thomson Co., Ltd., and the RV series manufactured by JTEKT Corporation can be mentioned. Since these cage-roller assemblies are originally widely used as functional units for bearing members (needle bearings), each part is assembled with relatively high precision. Therefore, by directly using them as the annular unit 2 of the toothed belt pulley 1, the accuracy of the pulley groove portion 24 can be easily ensured.

[0034] (Fixing means 3) As shown in FIGS. 1 to 3, the fixing means 3 includes an annular base body 31 and a cover body 32 fixed to the base body 31. The fixing means 3 serves to fix (connect) the annular unit 2 to the rotating shaft S and to fix the positional relationship of the annular unit 2 in the rotational axis direction.

[0035] As shown in FIG. 2(A), the base body 31 includes an inner peripheral base portion 31A that covers the inner peripheral side of the annular unit 2, a side surface base portion 31B that covers one side surface of the annular unit 2, an outer peripheral base portion 31C that covers a part of one side of the outer periphery of the annular unit 2, a boss portion 31D in which a key groove 31D1 fitted to the convex key of the rotating shaft S is formed, and a connecting portion 31E that connects the inner peripheral base portion 31A and the boss portion 31D, and are integrally formed.

[0036] The cover body 32 is integrally formed with a side cover portion 32A that covers the side surface on the other side of the annular unit 2 and an outer peripheral cover portion 32B that covers a part of the outer periphery on the other side of the annular unit 2.

[0037] The base body 31 and the cover body 32 are configured to be divided in the rotation axis direction, and are fixed in a manner that sandwiches the annular unit 2 in the width direction between the side base portion 31B and the side cover portion 32A. Specifically, the connecting portion 31E of the base body 31 and the side cover portion 32A are fixed by rivets 33A to 33D (bolts and nuts may also be used). Here, as shown in FIG. 3(B), the base body 31 and the cover body 32 are formed such that the inner width 3A in the rotation axis direction between the side base portion 31B of the base body 31 that covers one side surface of the annular unit 2 and the side cover portion 32A of the cover body 32 that covers the other side surface of the annular unit 2 is slightly smaller than the outer width 2A in the rotation axis direction of the annular unit 2. And the annular unit 2 is sandwiched between the base body 31 and the cover body 32 in a state compressed in the rotation axis direction. For example, the inner width 3A is formed to be 0.3 mm smaller than the outer width 2A, and the annular unit 2 is sandwiched between the base body 31 and the cover body 32 in a state compressed by 0.3 mm in the rotation axis direction.

[0038] In this way, by sandwiching the annular unit 2 between the base body 31 and the cover body 32 that are divided in the rotation axis direction and then fixing the base body 31 and the cover body 32, the annular unit 2 and the fixing means 3 (the base body 31 and the cover body 32) can be integrated. Thereby, the annular unit 2 can be easily fixed to the rotation axis S. Also, since the inner width 3A between the side base portion 31B of the base body 31 and the side cover portion 32A of the cover body 32 is formed to be slightly smaller than the outer width 2A of the annular unit 2, and the annular unit 2 is sandwiched between the base body 31 and the cover body 32 in a state compressed in the rotation axis direction, the annular unit 2 can be fixed between the base body 31 and the cover body 32. As a result, the annular unit 2 and the fixing means 3 (base body 31 and cover body 32) can be fixed so as not to rotate relative to each other (without slipping). According to the above configuration, when the toothed belt pulley 1 is used as a driving pulley, power can be reliably transmitted from the rotating shaft S to the toothed belt 4 via the base body 31, the cover body 32, the annular unit 2, and the roller 22. Also, when the toothed belt pulley 1 is used as a driven pulley, power can be reliably transmitted from the toothed belt 4 to the rotating shaft S via the roller 22, the annular unit 2, the base body 31, and the cover body 32.

[0039] Further, in the base body 31 and the cover body 32, two knock pin portions 31E1 (corresponding to convex portions) are formed at the connecting portion 31E of the base body 31, and two hole portions 32A1 (corresponding to concave portions) are provided in the side cover portion 32A of the cover body 32. The two knock pin portions 31E1 and the two hole portions 32A1 are fitted concentrically with each other. That is, the base body 31 and the cover body 32 have a fitting structure. As a result, the base body 31 and the cover body 32 can be accurately arranged concentrically. Note that, in the base body 31 and the cover body 32, two hole portions (corresponding to concave portions) may be formed at the connecting portion 31E of the base body 31, and two knock pin portions (corresponding to convex portions) may be provided in the side cover portion 32A of the cover body 32.

[0040] Also, the inner peripheral base portion 31A of the base body 31 faces a plurality of rollers 22 on the inner peripheral side of the annular unit 2 and is arranged so as to be in contact with the plurality of rollers 22 (see Fig. 3(C)). Specifically, when the toothed belt 4 is wound around the annular unit 2 and the load by the toothed belt 4 is applied to each roller 22, each roller 22 held in a loose fit state in the pocket 23 of the annular unit 2 moves radially inward, so that each roller 22 and the inner peripheral base portion 31A of the base body 31 are arranged to be in contact with each other. As a result, the load by the toothed belt 4 can be released to the base body 31 side, and the load on the annular unit 2 including the plurality of rollers 22 can be reduced.

[0041] Further, in Embodiment 1, as shown in FIG. 3(C), when each roller 22 comes into contact with the inner peripheral base portion 31A of the base body 31, the base body 31 is disposed on the inner diameter side of the annular unit 2 so that no gap is formed between each roller 22 and the inner diameter side anti-loosening portion 213C. According to the above configuration, there is no gap (separation distance) between the roller 22 and the inner diameter side anti-loosening portion 213C, and the roller 22 can be held such that the radial play allowance of the roller 22 is maximized between the outer diameter side anti-loosening portions 213A and 213B and the inner diameter side anti-loosening portion 213C (or the inner peripheral base portion 31A of the base body 31) (the roller 22 can be held in the most loosely fitting state in the pocket 23). As a result, each roller 22 can be brought into contact (inscribed) with the inner peripheral base portion 31A of the base body 31 at the innermost peripheral position, the radial movement distance of each roller 22 can be maximized, and foreign matter that has entered between each roller 22 and the inner peripheral base portion 31A of the base body 31 can be easily discharged.

[0042] Further, on the other end of the outer peripheral base portion 31C of the base body 31, as shown in FIGS. 2(A) and 3(B), a base body side flange portion 31C1 extending radially outward is formed, and on one end of the outer peripheral cover portion 32B of the cover body 32, a cover body side flange portion 32B1 extending radially outward is formed. The distance between the base body side flange portion 31C1 and the cover body side flange portion 32B1 is formed to be larger than the width of the toothed belt 4 wound around the annular unit 2. Thereby, by guiding the toothed belt 4 between the base body side flange portion 31C1 and the cover body side flange portion 32B1, the toothed belt 4 can be wound around the outer periphery of the annular unit 2 without lateral displacement in the width direction.

[0043] For the toothed belt pulley 1 configured as described above, the boss portion 31D is fixed (connected) to the connecting portion 31E of the base body 31 by welding, and a convex key of the rotating shaft S is fitted into the key groove 31D1 of the boss portion 31D, whereby it is fixed to the rotating shaft S.

[0044] The materials of the base body 31 and the cover body 32 (fixing means 3) are not particularly limited as long as they are materials having sufficient rigidity. For example, metals such as carbon steel, stainless steel, and aluminum alloy, or resins (such as polyacetal resin) may be used.

[0045] According to the pulley 1 for a toothed belt having the above configuration, a bearing unit that is widely used as a roller bearing (rolling bearing) further including at least one raceway ring (outer ring and / or inner ring arranged concentrically) that rolls can be diverted as the annular unit 2 of the pulley 1 for a toothed belt. Therefore, like the configuration of the pulley for a toothed belt in Patent Document 1, it is not necessary to arrange a plurality of pin portions (corresponding to rollers) between a base portion and a cover portion that face each other in the rotational axis direction of the pulley for a toothed belt (specifically, one end of each pin portion must be inserted into an insertion hole formed in the base portion, and the other end of each pin portion must be inserted into an insertion hole formed in the cover portion), and the production of the pulley 1 for a toothed belt is easy, that is, the productivity (particularly the productivity in the assembly process) can be improved.

[0046] (Embodiment 2) In the pulley 1 for a toothed belt of Embodiment 1, when each roller 22 contacts the inner peripheral base portion 31A of the base body 31, the base body 31 is arranged on the inner diameter side of the annular unit 2 so that no gap is formed between each roller 22 and the inner diameter side anti-loosening portion 213C (see FIG. 3(C)), and the roller 22 is held between the outer diameter side anti-loosening portions 213A and 213B and the inner diameter side anti-loosening portion 213C (or the inner peripheral base portion 31A of the base body 31) so that the radial play of the roller 22 in the pocket 23 is maximized (the base body 31 (inner peripheral base portion 31A) is in contact with the roller 22 at the innermost peripheral side position).

[0047] On the other hand, in the toothed belt pulley 201 of Embodiment 2, as shown in FIGS. 7 to 9, the base body 31 sandwiches each roller 22 between the outer diameter side anti-loosening portions 213A and 213B facing each other and between the inner peripheral base portion 31A of the base body 31, and is disposed on the inner diameter side of the annular unit 2 (see FIG. 9(C)) (the base body 31 (inner peripheral base portion 31A) is in contact with the roller 22 at the outermost peripheral side position). Note that other configurations of Embodiment 2 are the same as those of Embodiment 1. According to the configuration of this toothed belt pulley 201, the play allowance of each roller 22 in the radial direction in the pocket 23 can be set to 0 (zero).

[0048] Therefore, each time the tooth portion of the toothed belt 4 engages and disengages with the space between the rollers 22 (pulley groove portion 24), it is possible to prevent the generation of abnormal noise (rattling sound) caused by the movement of the roller 22 in the radial direction and contact with the retainer 21 (column portion 213). Furthermore, the depth of the pulley groove portion 24 and the pitch between two adjacent rollers 22 can be maximized (see FIG. 9(C)). As a result, the degree of freedom in the design (shape and dimensions) of the tooth portion of the toothed belt 4 that engages with the pulley groove portion 24 can be increased, and the meshing property between the pulley groove portion 24 of the toothed belt pulley 201 and the tooth portion of the toothed belt 4 can be made the best. Furthermore, a certain distance (separation distance), for example, about 0.3 mm, can be ensured between the roller 22 and the inner diameter side anti-loosening portion 213C. Therefore, the effect of discharging foreign matter from the bottom of the pulley groove portion 24 to the outside and reducing noise (not only frictional noise but also cracking sound and knocking sound) can be obtained.

[0049] (Embodiment 3) In the toothed belt pulley 1 of Embodiment 1, the roller 22 is held such that the play allowance of the roller 22 in the radial direction in the pocket 23 is maximized (for example, about 1 mm). On the other hand, in the toothed belt pulley 201 of Embodiment 2, the roller 22 is held such that the play allowance of each roller 22 in the radial direction in the pocket 23 is 0 (zero).

[0050] Therefore, in the pulley 301 for the toothed belt according to Embodiment 3, as shown in FIGS. 10 to 12, the rollers 22 are held such that the radial play of each roller 22 in the pocket 23 is between Embodiment 1 and Embodiment 2 (for example, about 0.5 mm) (see FIG. 12(C)) (the base body 31 (inner peripheral base portion 31A) is in contact with the roller 22 at the radial bearing reference position). Specifically, when each roller 22 comes into contact with the inner peripheral base portion 31A of the base body 31, the base body 31 is arranged on the inner diameter side of the annular unit 2 so that a slight gap (a slit-shaped gap, for example, about 0.1 mm) is formed between each roller 22 and the inner diameter side anti-loosening portion 213C. Note that the other configurations of Embodiment 3 are the same as those of Embodiment 1.

[0051] In this case, a slight gap is formed between the roller 22 and the inner diameter side anti-loosening portion 213C, and the roller 22 can be held in a state where a radial play of the roller 22 is ensured to a certain extent (for example, about 0.5 mm) between the outer diameter side anti-loosening portions 213A and 213B and the inner diameter side anti-loosening portion 213C (or the inner peripheral base portion 31A of the base body 31). Thereby, while making it somewhat easier to discharge foreign matter that has entered between each roller 22 and the inner peripheral base portion 31A of the base body 31, it is possible to prevent, to a certain extent, the generation of abnormal noise due to the movement of the roller 22 in the radial direction and contact with the cage 21 (column portion 213).

[0052] (Other Embodiments) The inner peripheral base portion 31A of the base body 31 in Embodiments 1 to 3 is formed with a flat outer peripheral surface that contacts the roller 22 and is configured to be in line contact with the roller 22, but it may also be configured to be in surface contact with the outer peripheral surface on the inner diameter side of the roller 22 (see FIG. 15(C)) (the base body 31 is in contact with the roller 22 at the radial and circumferential bearing reference positions). For example, as shown in FIGS. 13 to 15, after the base body 31 is attached to the annular unit 2, a part of the inner peripheral base portion 31A facing the outer diameter side anti-loosening portions 213A and 213B is formed into a shape (wavy in side view) that bulges (plastic deformation) radially outward until it contacts the roller 22, and thus a pulley 401 for a toothed belt having wave portions 31A1 and 31A2 is obtained (see FIGS. 14(A) and 15(C)). In this case, the roller 22 is held not only in the radial direction but also in the circumferential direction X, and when the pulley groove portion 24 of the annular unit 2 engages with the tooth portion of the toothed belt 4, the roller 22 can be made less likely to contact the cage 21. In particular, when the roller 22 is held at the position of Embodiment 3, it is possible to prevent the roller 22 from contacting the cage 21 when the pulley groove portion 24 of the annular unit 2 engages with the tooth portion of the toothed belt 4. That is, for example, when the pulley 401 for a toothed belt is applied to a driving pulley, the torque transmission path can be made as follows: rotating shaft S → base body 31 → roller 22 → toothed belt 4, without passing through the cage 21. Therefore, wear of the cage 21 during the running of the toothed belt 4 can be most suppressed.

[0053] Further, the fixing means 3 (base body 31) does not necessarily have to include the boss portion 31D. For example, a mode can be formed in which a portion integrally extending radially outward from the rotating shaft S and the fixing means 3 (base body 31) are connected by bolts.

[0054] In addition, the pulley for a toothed belt according to the present invention can be applied to either the driving side pulley or the driven side pulley. Also, the application is not particularly limited and can be used.

Example

[0055] In the present invention, in a pulley for a toothed belt in which the tooth portion of the toothed belt engages with a pulley groove portion provided in the gap between two adjacent rollers, it is necessary to improve productivity. Therefore, in this example, pulleys for toothed belts according to the examples and comparative examples (hereinafter, each test specimen) were manufactured, an assembly test and a belt running test were conducted, and a comparative verification was performed. Next, the present invention will be described in more detail based on the embodiments, but the present invention is not limited to these embodiments.

[0056] (Common to each test specimen) (Annular unit) · "Cage - roller assembly": Model "FWF - 556532C - 2" manufactured by NSK Ltd. was used. · Inner diameter of the roller (reference value): 55 mm · Outer diameter of the roller (reference value): 65 mm · Shape and diameter of the roller: Cylindrical, 5 mm · Number of rollers: 24 · Width of the cage: 32 mm

[0057] (Fixing means) · It was configured to be divided into two parts in the rotation axis direction (base body and cover body). · Inner width of the fixing means (assembly of the base body and the cover body): Slightly smaller (interference fit tolerance +0 - 0.5 mm) than the width dimension (outer width) of the annular unit (cage), and the annular unit was clamped from both sides (in the rotation axis direction). · Only the base body was brought into contact with the roller from the radially inner side to fix or regulate the radial positional relationship of the roller. · The base body and the cover body were in - rolled and fitted by knock pins (at two diagonal positions). · The base body was connected to the rotation axis, and a boss portion (with a keyway) extending in the rotation axis direction was integrated by welding. · The base body (except for the boss portion) and the cover body were made of cold - rolled steel sheet (SPCC, thickness 1.6 mm) (conforming to JIS G 3141:2005). · The base body and the cover body were integrated via rivets (at four positions).

[0058] (Assembly procedure of the pulley for the toothed belt (annular unit, fixing means)) (1) First, the base body was fitted into the annular unit (cage - roller assembly) from one side (left side) in the rotation axis direction. (2) Next, the cover body was externally fitted onto the annular unit from the other side (right side) in the direction of the rotation axis, and integrated with the base body via rivets (at 4 locations) in an inlay fit state by knock pins (at 2 locations). The assembly of the pulley for the toothed belt is thus completed.

[0059] (Differences among the test specimens) · For Examples 1 to 3, the diameter of the outer peripheral surface that contacts the roller of the base body was changed, and the holding position of the roller in the radial direction was changed for each test specimen.

[0060] (Example 1) (Figs. 1 to 3) Example 1 is an example corresponding to Embodiment 1. The base body contacts (is inscribed in) the roller at the innermost peripheral side position. · Pitch circle diameter (P.C.D.) of the roller: 59 mm · Pitch between two adjacent rollers: 7.723 mm · Radial play allowance of the roller: 1 mm · Contact state between the roller and the base body: line contact · Rotation of the roller: possible · Depth of the pulley groove: 2.8 mm · Minimum separation distance between the roller and the inner diameter side anti-loosening portion: 0 mm

[0061] (Example 2) (Figs. 10 to 12) Example 2 is an example corresponding to Embodiment 3. The base body contacts (is inscribed in) the roller at the radial bearing reference position. · Pitch circle diameter (P.C.D.) of the roller: 60 mm · Pitch between two adjacent rollers: 7.854 mm · Radial play allowance of the roller: 0.5 mm · Contact state between the roller and the base body: line contact · Rotation of the roller: possible · Depth of the pulley groove: 3.3 mm · Minimum separation distance between the roller and the inner diameter side anti-loosening portion: 0.1 mm

[0062] (Example 3) (Figs. 7 to 9) Example 3 is an example corresponding to Embodiment 2. The base body is in rolling contact (inscribed) at the outermost peripheral side position. · Pitch circle diameter (P.C.D.) of the roller: 61 mm · Pitch between two adjacent rollers: 7.985 mm · Radial play of the roller: 0 mm · Contact state between the roller and the base body: line contact · Rotation of the roller: possible · Depth of the pulley groove: 3.8 mm · Minimum separation distance between the roller and the inner diameter side anti-loosening portion: 0.3 mm

[0063] (Example 4) (Figs. 13 to 15) Example 4 is an example corresponding to other embodiments. The basic configuration is based on Example 2 (Embodiment 3). The base body is in rolling contact (inscribed) with the roller at the bearing reference position in the radial direction and the circumferential direction. · Pitch circle diameter (P.C.D.) of the roller: 60 mm · Pitch between two adjacent rollers: 7.854 mm · Radial play of the roller: 0.5 mm · Contact state between the roller and the base body: line contact at the center in the width direction of the roller, and surface contact at both ends in the width direction of the roller · Rotation of the roller: possible · Depth of the pulley groove: 3.3 mm · Minimum separation distance between the roller and the inner diameter side anti-loosening portion: 0.1 mm

[0064] (Assembly procedure) · After fitting the base body to the annular unit, except for the point where the inner peripheral base portion of the base body facing the outer diameter side anti-loosening portion is formed into a shape (wavy in side view) that is raised (plastically deformed) radially outward until it comes into contact with the roller, the toothed belt pulley was assembled according to the aforementioned assembly procedures (1) and (2) in the same manner as in Examples 1 to 3.

[0065] (Comparative Example 1) (not shown) (Toothed belt pulley) ·As a pulley for a toothed belt of the type in which the teeth engage in the gap between two adjacent rollers, a configuration according to Example 1 described in Patent Document 1 was adopted without diverting the "cage roller assembly" (general-purpose product) as a functional unit. ·As an assembly procedure, except that the number of rollers (pin parts) corresponding to the number of a plurality of groove parts (pulley groove parts) was prepared and these plurality of rollers were arranged between a base body and a cover body facing each other in the rotational axis direction of the toothed belt pulley (specifically, one end of each roller was inserted into an insertion hole formed in the base body, and the other end of each roller was inserted into an insertion hole formed in the cover body), a toothed belt pulley was formed according to Example 2 (Embodiment 3). ·Pitch circle diameter (P.C.D.) of the roller: 60 mm ·Pitch between two adjacent rollers: 7.854 mm ·Radial play allowance of the roller: 0 mm ·Rotation of the roller: Not possible ·Material of the roller: Stainless steel (SUS303) ·Depth of the pulley groove part: 5.0 mm

[0066] (Comparative Example 2) (not shown) ·As a pulley for a toothed belt of the type in which the teeth engage in the gap between two adjacent rollers, a configuration according to Example 2 described in Patent Document 1 was adopted without diverting the "cage roller assembly" (general-purpose product) as a functional unit. ·As an assembly procedure, except that the number of cylindrical rollers (pin parts) and support shafts corresponding to the number of a plurality of groove parts (pulley groove parts) was prepared, and a plurality of roller bodies were produced by inserting the support shafts through the cylindrical rollers to form integral roller bodies, and these plurality of roller bodies were arranged between a base body and a cover body facing each other in the rotational axis direction of the toothed belt pulley in the same manner as in Comparative Example 1, a toothed belt pulley was formed according to Example 2 (Embodiment 3). Specifically, one end of each support shaft was inserted into an insertion hole formed in the base body, the other end of each support shaft was inserted into an insertion hole formed in the cover body and fixed, and the cylindrical rollers were formed to be relatively rotatable about the support shafts. ·Pitch circle diameter (P.C.D.) of the roller: 60 mm ·Pitch between two adjacent rollers: 7.854 mm · Radial play of the roller: 0 mm · Rotation of the roller: Allowed (the cylindrical roller can rotate relative to the support shaft) · Material of the roller: Stainless steel (SUS303) · Depth of the pulley groove: 5.0 mm

[0067] [Evaluation of the toothed belt pulley: Items, methods, criteria] · For each test specimen (Examples 1 to 4, Comparative Examples 1 to 2), in order to determine whether a toothed belt pulley capable of solving the problems of the present application was obtained, productivity (i.e., whether the toothed belt pulley can be assembled in a short time), meshing property (i.e., the meshing property essential as dynamic performance), quietness (i.e., the presence or absence of noise during belt running), transmission efficiency (i.e., torque cross), and foreign matter release property (i.e., the wear amount of the roller when muddy water enters) were verified.

[0068] [Assembly test] (Test method) · To determine productivity (whether the toothed belt pulley can be assembled in a short time), the time required for assembling the toothed belt pulley was measured. · The evaluation result (assembly time) was expressed as an index with the assembly time of Comparative Example 1 being 100.

[0069] (Judgment criteria) · When the assembly time (index) is less than 10, it was determined that the productivity (assemblability) can be most significantly improved compared to the case where the "cage - roller assembly" (general - purpose product) is not used as the annular unit, and it was judged as an a judgment. · When the assembly time (index) is 10 or more and less than 50, it was determined that the productivity (assemblability) can be significantly improved compared to the case where the "cage - roller assembly" (general - purpose product) is not used as the annular unit, and it was judged as a b judgment. · When the assembly time (index) is 50 or more and less than 100, it was determined that the productivity (assemblability) can be improved compared to the case where the "cage - roller assembly" (general - purpose product) is not used as the annular unit, and it was judged as a c judgment. · When the assembly time (index) is 100 or more, it was determined as a d judgment, judging that productivity (assemblability) cannot be improved compared to the case where the "cage - roller assembly" (general - purpose product) is not used as an annular unit. · From the viewpoint of the suitability for actual use in this application (assemblability of the toothed - belt pulley), the toothed - belt pulleys for a, b, and c judgments were set as the qualified level.

[0070] [Belt running test] (Pulley layout) · Each test specimen was used as the driving pulley. · Driving pulley: Each test specimen (number of pulley groove parts: 24) · Driven pulley: A normal toothed - belt pulley (a machined product from a cylindrical steel material), that is, the pulley groove part is formed in a shape substantially similar to the belt tooth part (number of pulley groove parts: 12, groove depth: 3.4 mm) · Ratio of the number of grooves between the driving pulley and the driven pulley: 2

[0071] (Toothed belt) · Belt width: 10 mm · Shape and size of the tooth part: · Tooth pitch: With the design reference value of 8 mm, it was appropriately changed for each test specimen (in proportion to the size of the pitch between two adjacent rollers). · Tooth part: The shape of the tooth part was set as the S - tooth shape belonging to straight teeth (the same STPD type as in Example 1 of Patent Document 1), and the height of the tooth part and the width of the tooth root were appropriately changed for each test specimen (in proportion to the size of the tooth pitch). · Belt circumference: 600 mm · Rubber - like elastic body: Thermosetting urethane elastomer (the same configuration as in Example 1 of Patent Document 1) · Tensile body: Carbon fiber, diameter 0.9 mm (the same configuration as in Example 1 of Patent Document 1)

[0072] (Test method) · In order to determine the meshing property (the meshing property essential as a dynamic performance), the belt was run by a two - axis running test machine, and the meshing property of the driving pulley during belt running was evaluated. · After adjusting the axial distance between the driving pulley and the driven pulley so that the belt tension becomes 100 N, with a load torque of 10 Nm applied to the rotating shaft of the driven pulley, the driving pulley was rotated at 60 rpm to run the toothed belt. The ambient temperature during the test was set to room temperature (25 ± 3°C). Then, 1 hour after the start of rotation of the driving pulley, the rotation of the driving pulley was stopped to end the test. · The meshing performance of the driving pulley was evaluated by visually observing the degree of vertical movement of the toothed belt between the pulleys (specifically, the part in front of the driving pulley where the belt is wound) immediately before the end of the test.

[0073] (Judgment criteria) · When no vertical movement was observed, it was evaluated as excellent meshing performance and judged as a. · When slight vertical movement was observed, it was evaluated as good meshing performance and judged as b. · When there was vertical movement but it was relatively small, it was evaluated that the meshing performance was within the allowable range (applicable to relatively low-load applications) and judged as c. · When the vertical movement was relatively large, it was evaluated that meshing transmission was difficult and judged as d. · From the perspective of suitability for actual use in this application (meshing performance, which is essential as dynamic performance), the toothed belt pulleys with a, b, and c judgments were regarded as the qualified level.

[0074] [Sound pressure measurement test] (Test method) · To determine the quietness (presence or absence of noise during belt running), the noise emitted by the driving pulley (each test specimen) was measured and evaluated with a noise meter during the belt running test. · Specifically, during belt running, a noise meter (CHE-SD1 manufactured by Sunwa Supply) was installed at a position approximately 30 mm away from the outside of the driving pulley (each test specimen), and the sound pressure (noise level) was measured with the sound collecting microphone of the noise meter. The lower the sound pressure, the lower the noise during belt running, and it can be judged that the quietness is excellent.

[0075] (Judgment criteria) · When no noise above 80 dBA was detected, it was determined that the quietness was excellent, and an a judgment was made. · When noise above 80 dBA was detected, it was determined that the noise was significant during use as a pulley and the quietness was not practical, and a d judgment was made. · From the perspective of suitability for actual use in this application (presence or absence of noise during belt running), the toothed belt pulley with an a judgment was set as the qualified level.

[0076] [Torque cross measurement test] (Test method) · To determine the transmission efficiency, the belt was run by a two-axis running test machine similar to the belt running test, and the torque cross (the difference between the driving torque and the driven torque) was measured and evaluated. · Specifically, after adjusting the axial distance between the driving pulley and the driven pulley so that the belt tension becomes 100 N using the same belt as the belt running test, the driving pulley was rotated at 200 rpm with the driven pulley unloaded, and the difference between the driving torque and the driven torque at that time was calculated as the torque cross. The smaller the value of the torque cross, the smaller the energy loss of the pulley and the better the transmission efficiency can be judged. · Note that the torque cross was expressed as an index with the torque cross value (1.2 N·m) when using Comparative Example 1 as the driving pulley set to 100.

[0077] (Judgment criteria) · When the torque cross (index) is less than 90, it was determined that the transmission efficiency can be significantly improved compared to the toothed belt pulley of Comparative Example 1, and an a judgment was made. · When the torque cross (index) is 90 or more and less than 100, it was determined that the transmission efficiency can be slightly improved compared to the toothed belt pulley of Comparative Example 1, and a b judgment was made. · When the torque cross (index) is 100 or more, it was determined that the transmission efficiency has not improved compared to the toothed belt pulley of Comparative Example 1, and a d judgment was made. · From the perspective of suitability for actual use in this application, the toothed belt pulleys with a and b judgments were set as the qualified level.

[0078] [Mud and water droplet test] (Muddy water dripping conditions) · The muddy water dripped onto the back of the toothed belt stretched above the pulley for the toothed belt (drive pulley). · Composition of the muddy water: 70% by weight of tap water and 30% by weight of one type of powder for JIS Z 8901:2006 test (quartz sand) · Dripping rate of the muddy water: 500 cc / min

[0079] (Test method) · In order to determine the foreign object release property, a belt running test under muddy water dripping conditions was carried out, and the wear amount of the roller of the toothed belt pulley due to mud was measured by the following method. · Under the same test apparatus and test conditions as the belt running test, with the belt hung on the drive pulley and the driven pulley, the drive pulley was rotated at 60 rpm to run the toothed belt, and the dripping / stopping of the muddy water was repeated using the muddy water dripping device. · The dripping cycle of the muddy water was set as 1 minute of dripping / 5 minutes of stopping per cycle, and this was repeated for 10 cycles. · At the 10th cycle, after stopping the dripping of the muddy water and running the belt for 5 minutes, the rotation of the drive pulley was stopped to end the test. Then, the toothed belt pulley (each test specimen) was disassembled, and the wear amount (change in outer diameter) of the roller was examined by measuring the outer diameter of the roller. If the foreign object release property is low, the mud that has entered between the roller in the pulley and the base body will wear the roller during belt running. Therefore, it can be judged that the lower the wear amount of the roller, the higher the foreign object release property under foreign object intrusion conditions.

[0080] (Judgment criteria) · When the wear amount of the roller is 0.05 mm or less, it is judged that the foreign object release property is very high, and it is designated as an a judgment. · When the wear amount of the roller is greater than 0.05 mm but 0.2 mm or less, it is judged that the foreign object release property is within the allowable range, and it is designated as a c judgment. · When the wear amount of the roller is greater than 0.2 mm, it is judged that there is no foreign object release property and it is not practical, and it is designated as a d judgment. · From the perspective of the suitability (foreign object release property) for actual use in this application, the toothed belt pulleys with a and c judgments were regarded as the qualified level.

[0081] (Comprehensive Judgment) · As the criteria for comprehensive judgment (ranking) of the pulley for toothed belt that can solve this problem, it is as shown in Table 1 below based on the judgment results in the above five evaluation items (productivity, meshing property, quietness, transmission efficiency, foreign matter discharge property), and a C rank or above is considered qualified.

[0082]

Table 1

[0083] (Verification Results and Considerations) The verification results are shown in Table 2.

Table 2

[0084] (Comparison of Changing the Presence or Absence of Diversion of "Cage - Roller Assembly") (Comparative Examples 1 - 2) Comparative Examples 1 and 2 relate to a pulley for toothed belt in which the tooth portion of the toothed belt engages with a pulley groove portion provided in the gap between two adjacent rollers. As the configuration described in Patent Document 1, it is an example in which the "cage - roller assembly" (general - purpose product) is not diverted as a functional unit, and each roller is arranged between a base body and a cover body facing each other in the rotational axis direction of the pulley for toothed belt. In Comparative Example 1, one end of each roller is inserted into an insertion hole formed in the base body, and the other end of each roller is inserted into an insertion hole formed in the cover body. As a result, in the assembly process, the assembly time is significantly long, and it is judged as "d" in the evaluation of productivity. Moreover, since it is judged as "d" in all evaluations of meshing property, quietness, transmission efficiency, and foreign matter discharge property, the comprehensive judgment is a D rank (unqualified). In Comparative Example 2, by changing each roller in Comparative Example 1 into a roller body in which a support shaft was inserted through a cylindrical roller and integrated, each roller became relatively rotatable about the support shaft, and perhaps because the pulley groove portion and the teeth portion of the toothed belt could mesh smoothly, although improvements were seen in the evaluation of meshing property, quietness, transmission efficiency, and foreign matter discharge property, the process of inserting a support shaft through each roller and integrating it as a roller body was added, resulting in an additional assembly time compared to Comparative Example 1 in the assembly process, and it was determined as d in the evaluation of productivity, and it could not be said to be practical from the viewpoint of productivity (assemblability), so it was ranked D (failed) in the comprehensive determination.

[0085] (Examples 1 to 4) Examples 1 to 4 are examples in which a "cage - roller assembly" (general - purpose product), which is a bearing unit generally used as a roller bearing (rolling bearing), is diverted as an annular unit of the toothed - belt pulley in which the teeth portion of the toothed belt engages with the pulley groove portion provided in the gap between two adjacent rollers. In Examples 1 to 4, by diverting the "cage - roller assembly" (general - purpose product) as an annular unit of the toothed - belt pulley, the process of inserting one end of each roller into the insertion hole formed in the base body and inserting the other end of each roller into the insertion hole formed in the cover body became unnecessary, and the assembly time was significantly shortened. Therefore, it was found that the productivity (assemblability) was remarkably improved in the assembly process (a or b determination). Furthermore, as an annular unit of the toothed - belt pulley, since the rollers are held in a loose - fitting state in a pocket surrounded by the outer - diameter side anti - loosening portions facing each other, the inner - diameter side anti - loosening portions facing each other, and a pair of annular portions, it was possible to easily discharge foreign matter that had entered between each roller and the base body. Therefore, it was found that in Examples 1 to 4 compared with Comparative Examples 1 and 2, the wear amount of the rollers during belt running under muddy water dripping conditions was small, and the foreign - matter discharge property was also excellent (a determination).

[0086] (Comparison of changing the diameter of the outer peripheral surface of the base body in contact with the roller) (Examples 1 to 3) Examples 1 to 3 are examples in which the outer peripheral surface of the base body in contact with the roller is formed in a flat shape, and the holding position of the roller in the radial direction is changed for each specimen by changing the diameter of the outer peripheral surface in contact with the roller. In Examples 1, 2, and 3, as the outer diameter of the base body in contact with the roller is increased in order, and the roller is held more radially outward, the radial movement of the roller is restricted, and the volume of the pulley groove portion at the time of belt engagement (depth of the pulley groove portion × pitch between two adjacent rollers) can be increased. Proportionally, the volume of the tooth portion of the belt (height of the tooth portion × width at the tooth root) could be formed larger. Therefore, it was found that the meshing property with the toothed belt was improved, the vertical movement during belt running was reduced, and the torque cross during power transmission was reduced, resulting in an improvement in transmission efficiency. In particular, in Example 3, in which the outer diameter of the base body was the largest and the base body was arranged on the inner diameter side of the annular unit so that each roller was sandwiched between the outer diameter side anti-loosening portions facing each other and the base body, the most favorable results (a judgment) were obtained in all evaluations of productivity, meshing property, quietness, transmission efficiency, and foreign matter release property, and a pulley for a toothed belt with an overall judgment of A rank was obtained. That is, Example 3, in which the base body is arranged on the inner diameter side of the annular unit so that each roller is sandwiched between the outer diameter side anti-loosening portions facing each other and the base body, goes against common sense in the use of bearing members. Intentionally, by adopting a configuration that holds the roller at the outermost peripheral side position, in the use of a pulley for a toothed belt, the productivity (assembling property) can be remarkably improved, and it is also the most excellent in terms of the meshing property and transmission efficiency, which are essential as dynamic performance, and it has been found that it can most suitably adapt to high-load applications.

[0087] On the one hand, it was found that the smaller the outer diameter of the base body in contact with the roller and the wider the radial movement distance (play allowance) of the roller, the smaller the wear amount of the roller during belt running under muddy water dripping conditions, and the better the foreign matter discharge property. In particular, in Example 1 where the base body is arranged on the inner diameter side (innermost peripheral side position) of the annular unit so that no gap is formed between the roller and the inner diameter side anti-loosening portion when the roller and the base body are in contact, the radial movement distance (play allowance) of the roller is maximized, and the roller is held in the most loosely fitting state in the cage. Perhaps because it was possible to easily discharge the muddy water that had entered between the roller and the base body, the wear amount of the roller under muddy water dripping conditions was zero, and it was found that the foreign matter discharge property was the best compared to other examples (a determination). That is, the mode in which the base body is arranged on the inner diameter side (innermost peripheral side position) of the annular unit so that no gap is formed between the roller and the inner diameter side anti-loosening portion when the roller and the base body are in contact is presumed to be suitably used in applications where foreign matter intrusion into the pulley is assumed, such as use outdoors in bad weather.

[0088] (Comparison of changing the shape of the outer peripheral surface of the base body in contact with the roller) (Example 4) In Example 4, the outer peripheral surface of the base body in contact with the roller is wavy in side view, and the base body is in surface contact with the outer peripheral surface on the inner diameter side of the roller. Compared with Examples 1 to 3 where the outer peripheral surface of the base body is flat, although the productivity decreased somewhat due to the forming process of the base body, the productivity (assembling property) was significantly improved compared with Comparative Examples 1 and 2, so it was judged as b in the productivity evaluation. Also, in terms of engagement property, quietness, transmission efficiency, and foreign matter discharge property, it was at a practically acceptable level (a or b determination), so it was ranked C in the comprehensive determination and reached the passing level. In Example 4, since the base body is in surface contact with the roller, the annular unit is no longer passed through in the torque transmission path of the drive pulley. However, there was no difference from Example 2 in the evaluation of engagement property, quietness, transmission efficiency, and foreign matter discharge property, and there was no particular difference in the use as a pulley for a toothed belt.

[0089] (Obtained effects) From the above verification results, regarding the pulley for a toothed belt in which the teeth of the toothed belt engage with the pulley groove portions provided in the gaps between two adjacent rollers, the pulleys for toothed belts of Examples 1 to 4 address the problem and use a "cage - roller assembly" (off - the - shelf product) not as a bearing member (needle bearing) but as an annular unit of a power transmission member (pulley for toothed belt). It was confirmed that the productivity can be significantly improved compared to the case where the "cage - roller assembly" (off - the - shelf product) is not used.

Explanation of Reference Signs

[0090] 1 Pulley for toothed belt 2 Annular unit 21 Retainer 211·212 Annular portion 213 Column portion 213A·213B Outer - diameter side anti - loosening portion 213C Inner - diameter side anti - loosening portion 22 Roller 23 Pocket 24 Pulley groove portion 3 Fixing means 31 Base body 32 Cover body 4 Toothed belt S Rotation axis

Claims

1. A pulley for a toothed belt comprising an annular unit around which a toothed belt is wound, and a fixing means for fixing the annular unit to a rotating shaft, The cyclic unit is a cage having a pair of annular portions and a plurality of pillar portions arranged at a predetermined interval in the circumferential direction and connecting the pair of annular portions, the pillar portions being formed with an outer diameter side anti-burr portion formed on the outer diameter side and an inner diameter side anti-burr portion formed on the inner diameter side; a plurality of cylindrical rollers each held in a loosely fitted state in a pocket surrounded by a pair of annular portions and between the outer diameter side stop portions of the opposing column portions and between the inner diameter side stop portions of the opposing column portions.

2. the fixing means has an annular base body facing the rollers, 2. The pulley for a toothed belt according to claim 1, wherein the rollers and the base body are arranged so as to be able to come into contact with each other.

3. 3. The pulley for a toothed belt according to claim 2, wherein the base body is disposed on the inner diameter side of the annular unit so that no gap is formed between each roller and the inner diameter side anti-burr portion when each roller comes into contact with the base body.

4. 3. The pulley for a toothed belt according to claim 2, wherein the base body is disposed on an inner diameter side of the annular unit so as to sandwich each roller between the opposing outer diameter side stopper portions and the base body.

5. The fixing means further includes a cover body, the base body is formed so as to cover an inner periphery, one side surface, and at least a part of an outer periphery of the annular unit, and is connectable to the rotating shaft; the cover body is formed to cover the other side surface and at least a part of the outer periphery of the annular unit and is capable of being fixed to the base body; an inner width in the rotational axis direction between a portion of the base body covering one side surface of the annular unit and a portion of the cover body covering the other side surface of the annular unit is smaller than an outer width of the annular unit in the rotational axis direction; 3. The toothed belt pulley according to claim 2, wherein the annular unit is sandwiched between the base body and the cover body in a state compressed in the direction of the rotation axis.

6. 6. The pulley for a toothed belt according to claim 5, wherein a recess formed on one of said base body and said cover body is concentrically fitted with a protrusion formed on the other of said base body and said cover body.

7. The base body is formed with a base body side flange portion extending radially outward, The cover body is formed with a cover body side flange portion extending radially outward, 6. The pulley for a toothed belt according to claim 5, wherein a distance between said base body side flange portion and said cover body side flange portion is greater than a width of said toothed belt.

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