JP2012132571A - Pulley structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulley structure, hardly causing fatigue fracture of a coil spring.SOLUTION: The pulley structure has a pulley 102 around which a belt can be wound, a hub structure 103 capable of relative rotation inside the pulley 102 with respect to the pulley 102, a spring storage chamber 106 formed between the pulley 102 and the hub structure 103, and the coil spring 107 stored in the spring storage chamber 106 and having one end in contact with the pulley 102 and the other end in contact with the hub structure 103. If rotation torque of a predetermined magnitude or more is transmitted, via the coil spring 107, between the pulley 102 and the hub structure 103, at least one of a first contact part 107a as a contact part with the pulley 102 and a second contact part 107b as a contact part with the hub structure 103, in the coil spring 107, slides while making contact with the pulley 102 or the hub structure 103.

Description

  The present invention relates to a pulley structure between two rotating bodies capable of relative rotation, and more specifically, relates to a pulley structure in which an elastic member connects the two rotating bodies to absorb rotational fluctuations.

  An alternator provided in the automobile for power generation is connected to and driven by a crankshaft provided in the engine. However, due to the characteristics of the internal combustion engine, the crankshaft connected to the crankshaft is subject to rotational fluctuations in which acceleration and deceleration are frequently repeated in the rotational direction.

  Here, the generator shaft of the alternator has a large moment of inertia. Therefore, in the configuration in which the power generation shaft and the crankshaft are connected using a pulley and a belt to transmit power, slippage occurs between the pulley and the belt each time the belt speed (crankshaft rotation speed) changes. Belt squealing and wear are induced.

  Furthermore, when the rotational fluctuation of the crankshaft is transmitted to the power generation shaft, there is a problem that the power generation mechanism of the alternator deteriorates and the power generation efficiency decreases.

  Accordingly, as a pulley suitable for the rotation transmission system, that is, a pulley that absorbs the rotational fluctuation of the crankshaft, for example, a pulley having an elastic member and a viscous fluid between two relatively rotatable bodies is known. (For example, refer to Patent Document 1).

  Patent Document 1 shows an example of a pulley structure that absorbs rotational fluctuation of a crankshaft using an elastic member and a special viscous fluid. This pulley structure has a rubber elastic member between the first rotating body and the second rotating body that can rotate relative to each other, and viscosity increases with an increase in shearing force that occurs when rotational fluctuation occurs. And a viscous fluid having properties. With this configuration, even if a torque that can generate a shearing stress exceeding the elastic limit of the elastic member acts on the pulley structure, the relative angle between the first rotating body and the second rotating body is increased by increasing the viscosity of the viscous fluid. The displacement is suppressed and the elastic member is prevented from being damaged by yielding or breaking.

  Moreover, the pulley structure which provided only the elastic member between the two rotary bodies (1st, 2nd rotary body) which can rotate relatively is also mentioned as an example (for example, refer patent document 2). The elastic member described in Patent Document 2 is a coil spring, and includes a spiral portion at one end portion, an end portion extending radially outward from the other end portion, and an intermediate spiral portion therebetween. ing.

  One end has an inner diameter that can be engaged with the cylindrical surface of the second rotating body with a gripping action. The other end portion is accommodated in an arc-shaped accommodation groove provided in the first rotating body, and the end portion extending outward in the radial direction is engaged and fixed.

  As long as a positive torque is present in the pulley structure by the movement of the belt, the first rotating body and the second rotating body are engaged and rotated. During this movement, the intermediate spiral allows the second rotating body to perform an instantaneous relative elastic rotational movement in the opposite direction relative to the first rotating body. Furthermore, when the crankshaft rotational fluctuation has decreased to a level sufficient to generate a predetermined negative torque between the two rotating bodies, the spiral portion at one end portion causes the second rotating body to be connected to the first rotating body. It comes into engagement with the surface of the second rotating body with a sliding action of rotating at a speed exceeding the rotational speed.

  In the configuration in which only the elastic member as described above is used to absorb the rotation fluctuation, it is possible to secure a larger relative angular displacement between the first rotating body and the second rotating body than in Patent Document 1. The tension fluctuation of the belt wound around the pulley can be reduced. As a result, noise due to belt squealing is reduced, and the durability of the belt is improved. Further, the cost advantage is enhanced by combining the coupling / disengaging mechanism with the one-way clutch function.

  A pulley used for an alternator in a serpentine drive mechanism for an automobile is also known (see, for example, Patent Document 3). The pulley described in Patent Document 3 includes a hub structure that rotates together with the armature assembly, and an AC generator pulley that is mounted on the hub structure, and the pulley structure is provided between the hub structure and the AC generator pulley. Coil springs are interposed between the ends of the coil springs to transmit the driven rotational motion of the AC generator pulley by the meandering belt to the hub structure, and the relative elastic rotation in the opposite direction to the AC generator pulley. It has a structure that allows exercise. An end portion of the coil spring is bent outward in the radial direction, and the end portion is accommodated in a notch provided in the hub structure and the AC generator pulley.

Japanese Patent Application Laid-Open No. 08-240246 Japanese Patent No. 3357391 Japanese Patent No. 3268007

  However, in the configuration of Patent Document 1, since an annular rubber is employed as an elastic member provided between the first rotating body and the second rotating body, generally the amount of elastic deformation within the elastic limit, that is, The relative angular displacement allowed between the two rotating bodies is not sufficiently ensured. Furthermore, the torque fluctuation accompanying the rotation fluctuation with respect to an alternator is couple | bonded using the pulley provided with the elastic member and the special viscous fluid which are shown by patent document 1, and the crankshaft and the alternator with a rotation fluctuation are couple | bonded. However, since the belt is likely to resonate due to tension fluctuations, new noise is generated and the durability of the belt is adversely affected.

  On the other hand, in a pulley structure using a coil spring as an elastic member as shown in Patent Document 2, problems such as belt resonance, noise accompanying it, and deterioration of belt durability occur as shown in Patent Document 1. Although not, the relative angular displacement between the pulley and the generator shaft of the alternator increases, and the coil spring may be damaged for the following reasons. That is, one end of the coil spring is accommodated in an arc-shaped accommodation groove provided in the rotating body, and the end portion extending outward or inward in the radial direction is engaged and fixed. Due to the relative rotational movement between the pulley and the generator shaft of the alternator accompanying the rotational fluctuation, stress concentration occurs in the curved portion of the extended portion. Therefore, this pulley structure has a possibility that the end portion where the coil spring is locked is subject to fatigue failure due to local repetitive stress generated every time the crankshaft rotates.

  Similarly, in the pulley structure described in Patent Document 3, stress concentration is likely to occur at the end of the coil spring fixed to the hub structure or the AC generator pulley, and within a relatively short period of time. However, there is a problem that the coil spring is damaged.

  The present invention has been made in view of the above-mentioned various points, and its main purpose is to ensure the resonance of the belt, the noise, the durability, and the relative angular displacement between the pulley and the generator shaft of the alternator. A coil spring is employed as a member that gently absorbs the relative angular displacement, and it is an object of the present invention to provide a pulley structure that is less susceptible to fatigue failure of the coil spring.

Means for Solving the Problems and Effects of the Invention

  The pulley structure according to the present invention is a coil as a member that gently absorbs the relative angular displacement of the pulley structure from the aspect of ensuring the resonance, noise and durability of the belt and the relative angular displacement between the pulley and the generator shaft of the alternator. The present invention relates to a pulley structure using a spring. And the pulley structure which concerns on this invention has the following some features, in order to achieve the said objective. That is, the pulley structure of the present invention has the following features alone or in combination as appropriate.

  The first feature of the pulley structure according to the present invention is that a first rotating body that allows a belt to be wound, and a second rotating body that can rotate relative to the first rotating body inside the first rotating body. And a spring accommodating chamber formed between the first rotating body and the second rotating body, being accommodated in the spring accommodating chamber, one end abutting on the first rotating body, and the other end being the A coil spring abutting against the second rotating body, and both ends of the coil spring are disposed in an elastically deformed state so that the diameter changes, and the first rotating body and the The second rotary body is in contact with the first rotary body and the second rotary body in a state where the elastic recovery of the diameter of the coil spring is suppressed, and a portion other than the end of the coil spring is Relative rotation of the first rotating body and the second rotating body Even if the diameter is deformed in the direction in which the diameter changes, no contact is made with either the first rotating body or the second rotating body, and a rotational torque of a predetermined size or more is applied via the coil spring. When transmitted between the first rotator and the second rotator, the coil spring is connected to the first abutting portion and the second rotator which are abutting portions with the first rotator. At least one of the second contact portions, which are contact portions, is to slide in a state of being in contact with the first rotating body or the second rotating body.

  According to this configuration, since the coil spring contacts the first rotating body while acting on the first rotating body by the force of elastic recovery, the rotational torque of the first rotating body is transmitted to the coil spring by the friction of the contact portion. Conversely, it is also possible to transmit the rotational torque of the coil spring to the first rotating body. Similarly, rotational torque can be transmitted between the second rotating body and the coil spring. Thereby, it is possible to transmit rotational torque between the first rotating body and the second rotating body. When the rotational torque is transmitted, the frictional force acting on the coil spring acts in a distributed manner on the contact portion of the coil spring, so that stress concentration on a part of the coil spring can be suppressed, and the coil spring fatigue is reduced. It is possible to suppress destruction.

  Further, a rotational torque that causes a force exceeding a static frictional force acting on the contact portion between the coil spring and the first rotating body or the second rotating body to act on the contacting portion is the first rotating body and the second rotating body. When transmitted to and from the rotating body, slip occurs at the contact portion between the coil spring and the first rotating body or at the contact portion between the coil spring and the second rotating body. Therefore, when the excessively large rotational torque is transmitted, the second rotating body can rotate relative to the first rotating body, and it is possible to suppress a sudden fluctuation in the rotational speed of the second rotating body. . Moreover, since it can suppress that excessively large rotational torque is transmitted via a coil spring, deterioration of a coil spring is suppressed.

  A second feature of the pulley structure according to the present invention is that the first rotation of the coil spring is increased when the amount of increase in rotational speed per unit time of the first rotating body is greater than or equal to a predetermined magnitude. At least one of a first contact portion that is a contact portion with a body and a second contact portion that is a contact portion with the second rotating body is attached to the first rotating body or the second rotating body. It is to slide in a state of being in contact with each other.

  According to this configuration, when the amount of increase in the rotational speed per unit time of the first rotating body exceeds a predetermined magnitude, the second rotating body is in a direction opposite to the rotation direction with respect to the first rotating body. Relative rotation. Therefore, it is possible to suppress a rapid increase in the rotation speed of the second rotation body that occurs when the rotation speed of the first rotation body increases rapidly.

  A third feature of the pulley structure according to the present invention is that the first rotating body in the coil spring when the amount of decrease in the rotational speed per unit time of the first rotating body is equal to or greater than a predetermined magnitude. At least one of the first contact portion that is a contact portion with the second rotating body and the second contact portion that is a contact portion with the second rotating body is in contact with the first rotating body or the second rotating body. And slipping in contact.

  According to this configuration, when the amount of decrease in the rotational speed per unit time of the first rotating body is greater than or equal to a predetermined magnitude, the second rotating body is in the same direction as the rotational direction with respect to the first rotating body. Relative rotation. Therefore, it is possible to suppress a rapid decrease in the rotational speed of the second rotator that occurs when the rotational speed of the first rotator rapidly decreases.

  A fourth feature of the pulley structure according to the present invention is that at least one of the contact surfaces of the first rotating body and the second rotating body with which the coil spring contacts is subjected to surface hardening treatment. It is that.

  According to this configuration, the contact portion of the first rotating body or the second rotating body is prevented from being worn by friction when the coil spring slides in a state of being in contact with the first rotating body or the second rotating body. Therefore, it is possible to stably transmit the rotational torque between the first rotating body and the second rotating body.

  Further, a fifth feature of the pulley structure according to the present invention is that at least one of the contact surfaces of the first rotating body and the second rotating body with which the coil spring contacts is the first surface of the coil spring. A surface state in which the coefficient of friction generated between the first contact portion which is a contact portion with the first rotating body or the second contact portion which is the contact portion with the second rotating body is reduced is obtained. It is processed.

  According to this configuration, since the frictional force acting between the coil spring and the first rotating body or the second rotating body is reduced, the coil spring is likely to slip. Therefore, the influence which a 2nd rotary body receives by the rotational speed fluctuation | variation of a 1st rotary body can be made smaller. Moreover, the rotational torque which acts on a coil spring becomes small and can suppress deterioration of a coil spring.

  Further, a sixth feature of the pulley structure according to the present invention is that the coil spring is an angular spring in which the material cross section of the coil spring is a square shape, and the first rotating body or the first That is, the surface in contact with the two rotating bodies and the material end surface of the angular spring are formed as surfaces that are smoothly continuous with each other.

  According to this configuration, the contact portion of the coil spring with the first rotating body and the second rotating body is flat and can stably maintain the contact state, and the tip of the coil spring can It is possible to prevent the surface of the first rotating body or the second rotating body from being damaged. Further, the coil spring can be easily inserted into the first rotating body or the second rotating body when the pulley structure is assembled.

  Further, a seventh feature of the pulley structure according to the present invention is that the coil spring is a square spring having a quadrangular material cross section of the coil spring, and the material end of the square spring has the first end. It is arrange | positioned through a clearance gap with respect to a rotary body and the said 2nd rotary body.

  According to this structure, since the contact part with the 1st rotary body and the 2nd rotary body in a coil spring is planar shape, it is possible to maintain a contact state stably. Moreover, between the corner | angular part of the contact surface side of the said 1st rotary body and the said 2nd rotary body among the corner | angular parts located in the material edge part of the said angular spring, and a 1st rotary body or a 2nd rotary body Since a gap is formed, it is possible to prevent the corner portion from coming into direct contact and scratching.

  Further, an eighth feature of the pulley structure according to the present invention is that the coil spring is an angular spring in which a material cross section of the coil spring is a square shape, and the first rotary body or the first It is that the crowning is given to the surface which contacts 2 rotary bodies.

  According to this configuration, the contact portion of the coil spring with the first rotating body and the second rotating body has a rounded shape, and can be lubricated while maintaining a stable contact state. Further, it is possible to prevent the surface of the first rotating body or the second rotating body from being damaged by the edge of the coil spring.

Sectional drawing of the pulley structure which concerns on 1st Embodiment of this invention. FIG. 10 is a first modification of the embodiment, similar to FIG. 1. FIG. 10 is a second modification of the embodiment, similar to FIG. 1. The figure containing the partial cross section about the modification shown in FIG. FIG. 10 is a diagram illustrating a third modification of the embodiment, similar to FIG. 2. Sectional drawing of the pulley structure which concerns on 2nd Embodiment of this invention. AA sectional drawing of FIG. BB sectional drawing of FIG. Sectional drawing of the pulley structure which concerns on 3rd Embodiment of this invention. (a) is DD sectional drawing of the pulley structure shown in FIG. 9 in the state which took out the coil spring from the accommodation groove | channel. (b) is DD sectional drawing of the coil spring taken out from the accommodation groove | channel of FIG. DD sectional drawing of FIG. CC sectional drawing of FIG. Sectional drawing of the pulley structure shown in FIG. 9 in the state by which the coil spring was loosened. Sectional drawing of the pulley structure shown in FIG. 9 in the state by which the coil spring was wound up. The longitudinal cross-sectional view of a coil spring. (A) is the figure which showed the principal part of sectional drawing of the pulley structure which concerns on 4th Embodiment of this invention. (B) is EE sectional drawing of (a). The longitudinal cross-sectional view of the pulley structure which concerns on 5th Embodiment of this invention. (A) The figure which showed the principal part of sectional drawing (equivalent to the FF sectional position of FIG. 17) of the pulley structure which concerns on 5th Embodiment of this invention. (B) The figure which showed the principal part of GG sectional drawing of (a). HH sectional drawing of FIG. II sectional drawing of FIG. The longitudinal cross-sectional view of the pulley structure which concerns on 6th Embodiment of this invention. (A) The figure which showed the principal part of sectional drawing (equivalent to the KK sectional position of FIG. 21) of the pulley structure which concerns on 6th Embodiment of this invention. (B) The figure which showed the principal part of LL sectional drawing of (a). JJ sectional drawing of FIG. The longitudinal cross-sectional view of an example of a pulley structure, and the enlarged view of the part. Sectional drawing of the pulley structure which concerns on 7th Embodiment of this invention. NN sectional drawing of the pulley structure shown in FIG. The figure which shows the 1st modification of a coil spring. FIG. 27 is a cross-sectional view of the coil spring shown in FIG. 26 taken along the line PP. The figure which shows the 2nd modification of a coil spring. Sectional drawing of the pulley structure which concerns on 8th Embodiment of this invention. The figure which shows the shape of the spring guide surface of the hub structure shown in FIG. The figure which shows the 1st modification of the shape of the spring guide surface of the hub structure shown in FIG. The figure which shows the 2nd modification of the shape of the spring guide surface of the hub structure shown in FIG.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. Here, an embodiment in which the pulley structure according to the present invention is installed on a power generation shaft of an automobile alternator will be described.

(First embodiment)
FIG. 1 is a cross-sectional view of a pulley structure according to a first embodiment of the present invention. A pulley structure 1 shown in FIG. 1 is installed on a power generation shaft (not shown) of an automobile alternator, and is rotated by transmitting engine power via a belt (not shown). The The pulley structure 1 includes a first rotating body 2 on the outer periphery thereof, and a pulley body 2 a on which the belt can be wound is provided on the outer peripheral surface of the first rotating body 2. The first rotating body 2 is formed in a substantially cylindrical shape.

  A bearing 4 is disposed on the inner circumference on the one axial end side of the first rotating body 2, and a bearing 5 is disposed on the inner circumference on the other axial end side. The bearing 4 and the bearing 5 support the second rotating body 3 so as to be rotatable relative to the first rotating body 2, and the second rotating body 3 is accommodated in the first rotating body 2. .

  A stop member (not shown) for fixing the bearing 4 and the bearing 5 so as not to come off is fitted on the outer periphery of the second rotating body 3. In addition, the shaft hole 3a of the second rotating body 3 is formed so that a generator shaft (not shown) of the alternator can be fixed.

  A spring accommodating chamber 6 is formed by the first rotating body 2 and the second rotating body 3 and the bearings 4 and 5. A coil spring 7 (square coil spring) having a rectangular cross section is housed in the spring housing chamber 6 and between the first housing groove 2b and the second housing groove 3b.

  In this embodiment, a spring holding portion 81 having a flat surface is projected from a first flange 41 ′ integrally formed with the first rotating body 2 toward the second flange 42 ′. On the other hand, the spring holding portion 82 is protruded toward the first flange 41 ′ from the second flange 42 ′ formed integrally with the second rotating body 3.

  One end of the coil spring 7 in the axial direction is inserted into the spring holding portion 81 on one side, and the other end in the axial direction of the coil spring 7 is inserted into the spring holding portion 82 on the other side. At this time, the end of the coil spring 7 is mounted in pressure contact with the first rotating body 2 and the second rotating body 3 by the diameter reducing force in the diameter reducing direction, which is the elastic force of the end.

  In the end portions (mounting portions) 85 and 86, the inner diameter of the end portion of the coil spring 7 is set smaller than the outer diameter of the spring holding portions 81 and 82 in a state without elastic deformation. Therefore, when the coil spring 7 is inserted into the outer peripheral surfaces 83 and 84 of the spring holding portions 81 and 82, a restoring force in the diameter reducing direction acts on the end portion of the coil spring 7 that is elastically deformed in the diameter increasing direction. Therefore, the spring holding portions 81 and 82 are tightened. Thus, the outer peripheral surfaces of the spring holding portions 81 and 82 are pressed against each other, and the coil spring 7 is mounted on the spring holding portions 81 and 82.

  In the present embodiment, as described above, the spring holding portions 81 and 82 are projected from the first rotating body 2 and the second rotating body 3, and the coil springs are opposed to the outer peripheral surfaces 83 and 84 of the spring holding portions 81 and 82. 7 is inserted, and the outer peripheral surfaces of the spring holding portions 81 and 82 are pressed against each other by the reduced diameter force of the mounting portions 85 and 86 as the ends of the inserted coil spring 7. . Thereby, the edge part of the coil spring 7 can be fixed with respect to the rotary bodies 2 and 3 with a simple structure.

  Further, the inner diameter of the end portion of the coil spring 7 is set smaller than the outer diameter of the spring holding portions 81 and 82 without elastic deformation, and the end portion of the coil spring 7 is set to the spring holding portion 81, It is mounted in a state where 82 is tightened. As a result, the end portion of the coil spring 7 can be firmly fixed to the rotating bodies 2 and 3 by using the restoring force of the coil spring 7 in the reduced diameter direction.

  As a first modification, as in the pulley structure 1a shown in FIG. 2, the first flange 41 ′ is formed with a spring holding portion 81 ′ that is a recess, and the second flange 42 ′ is also a recess. It can be modified to form a spring retaining portion 82 '. In FIG. 2, the same components as those in the present embodiment are denoted by the same reference numerals.

  Then, one end of the coil spring 7 in the axial direction is inserted into the spring holding portion 81 ′ on one side, and the other end in the axial direction of the coil spring 7 is inserted into the spring holding portion 82 ′ on the other side. The end portion of the coil spring 7 is mounted in pressure contact with the first rotating body 2 and the second rotating body 3 by the expanding force in the expanding direction which is the elastic force of the end portion. At this time, the outer diameters of the end portions of the coil springs 7 are set to be smaller than the inner diameters of the spring holding portions 81 ′ and 82 ′ without elastic deformation at the end portions (mounting portions) 85 ′ and 86 ′. ing. Accordingly, when the coil spring 7 is inserted into the inner peripheral surfaces 83 ′ and 84 ′ of the spring holding portions 81 ′ and 82 ′, the end of the coil spring 7 that is elastically deformed in the diameter reducing direction is in the diameter increasing direction. Since the restoring force acts, the spring holding portions 81 ′ and 82 ′ are brought into close contact with each other so as to push and spread the inner bottom side. Thus, the inner peripheral surfaces 83 ′ and 84 ′ of the spring holding portions 81 ′ and 82 ′ are brought into pressure contact with each other, and the coil spring 7 is mounted on the spring holding portions 81 ′ and 82 ′.

  Also in the first modification, the end of the coil spring 7 can be fixed to the rotating bodies 2 and 3 with a simple configuration. Further, by utilizing the restoring force in the diameter expansion direction of the coil spring 7, the end portion can be firmly fixed to the rotating bodies 2 and 3.

  As a 2nd modification, the shape of a spring holding | maintenance part can also be changed like the pulley structure 1b shown in FIG. The pulley structure 1b corresponds to the pulley structure 1 of the present embodiment, the spring holding portion 81 protrudes from the first rotating body 2, the spring holding portion 82 protrudes from the second rotating body 3, and the coil spring 7 The outer peripheral surfaces 83 and 84 of the spring holding portions 81 and 82 are configured to be pressed against each other by the diameter reducing force. In FIG. 3, the same components as those in the present embodiment are denoted by the same reference numerals.

  In the pulley structure 1b according to the second modification, the spring holding portion 81 has an outer peripheral surface 83 that is in pressure contact with the end portion 85 of the coil spring 7 in the direction of the center of rotation of the first rotating body 2 and the second rotating body 3. It is formed as a parallel peripheral surface. Similarly, in the spring holding portion 82, an outer peripheral surface 84 that is in pressure contact with the end portion 86 of the coil spring 7 is formed as a peripheral surface that is parallel to the rotation center direction of the first rotating body 2 and the second rotating body 3. . The spring holding portion 81 is provided with a tapered surface 91 that is inclined inward from the terminal end of the outer peripheral surface 83 and is separated from the coil spring 7 that is in pressure contact. Similarly, the spring holding portion 82 is provided with a tapered surface 92 that is inclined inward from the end of the outer peripheral surface 84 and is separated from the coil spring 7 that is press-contacted.

  In addition, FIG. 4 is the figure which showed the 1st rotary body 2 in the cross section about the pulley structure 1b. As shown in FIG. 4, the end portions 85 and 86 of the coil spring 7 are disposed so as to contact only the outer peripheral surfaces 83 and 84 of the spring holding portion.

  According to the pulley structure 1b of the second modified example, the outer periphery of the spring holding portions 81 and 82 formed in a straight cylindrical shape as a peripheral surface parallel to the rotation center direction of the first and second rotating bodies 2 and 3 The surfaces 83 and 84 can hold the end portions 85 and 86 of the coil spring 7 in a stable state by generating a uniform gripping force between the surfaces 83 and 84 and the end portions 85 and 86 of the coil spring 7 in pressure contact therewith. . In addition, when the pulley structure 1b is manufactured by further providing tapered surfaces 91 and 92 which are inclined inward from the terminal ends of the outer peripheral surfaces 83 and 84 and separated from the coil spring 7, 7 end portions 85 and 86 can be easily fitted and attached to the spring holding portions 81 and 82.

  As a 3rd modification, the shape of a spring holding | maintenance part can also be changed like the pulley structure 1c shown in FIG. This pulley structure 1c corresponds to the pulley structure 1a of the first modified example. The spring holding portion 81 ′ is recessed in the second rotating body 3, and the spring holding portion 82 ′ is provided in the first rotating body 2. And the inner peripheral surfaces 83 ′ and 84 ′ of the spring holding portions 81 ′ and 82 ′ are configured to be pressed against each other by the diameter expansion force of the coil spring 7. In FIG. 5, the same components as those in FIG. 2 are given the same reference numerals.

  In the pulley structure 1 c according to the third modification, the spring holding portion 81 ′ has an inner peripheral surface 83 ′ that is in pressure contact with the end portion 85 ′ of the coil spring 7. It is formed as a peripheral surface parallel to the rotation center direction. Similarly, the spring holding portion 82 ′ has an inner peripheral surface 84 ′ in pressure contact with the end portion 86 ′ of the coil spring 7 as a peripheral surface parallel to the rotation center directions of the first rotating body 2 and the second rotating body 3. Is formed. The spring holding portion 81 ′ is provided with a tapered surface 91 ′ that is inclined inward from the terminal end of the inner peripheral surface 83 ′ and is separated from the coil spring 7 that is in pressure contact. Similarly, the spring holding portion 82 ′ is provided with a tapered surface 92 ′ that is inclined inward from the end of the inner peripheral surface 84 ′ and is separated from the coil spring 7 that is press-contacted. .

  According to the pulley structure 1c of the third modified example, the spring holding portions 81 ′ and 82 ′ formed in a straight cylindrical shape as a peripheral surface parallel to the rotation center direction of the first and second rotating bodies 2 and 3 are used. The end portions 85 ′, 84 of the coil spring 7 in a stable state by generating a uniform gripping force between the inner peripheral surfaces 83 ′, 84 of the coil springs 7 and the ends 85 ′, 86 ′ of the coil spring 7 in pressure contact therewith. 86 'can be held. The pulley structure 1c is manufactured by further providing tapered surfaces 91 'and 92' that are inclined outward from the terminal ends of the inner peripheral surfaces 83 'and 84' and separated from the coil spring 7. In this case, the end portions 85 ′ and 86 ′ of the coil spring 7 can be easily fitted and attached to the spring holding portions 81 ′ and 82 ′.

  Further, the above embodiment can be implemented with the following modifications.

  For example, in FIG. 1, the coil spring 7 has an inner diameter smaller than that of the central region at the end of the coil spring 7 that contacts the spring holding portions 81 and 82, and the tightening force between the coil spring 7 and the spring holding portions 81 and 82. Can be adjusted to prevent slippage.

  Also in FIG. 2, the coil spring 7 has an outer diameter larger than that of the central region at the end of the coil spring 7 that abuts against the spring holding portions 81 ′ and 82 ′, and the coil spring 7 and the spring holding portions 81 and 82. The tightening force can be greatly adjusted.

(Second Embodiment)
Next, FIG. 6 is a longitudinal sectional view of a pulley structure according to a second embodiment of the present invention. 7 is a cross-sectional view taken along line AA in FIG. 6, and FIG. 8 is a cross-sectional view taken along line BB in FIG.

  An automobile internal combustion engine (not shown) includes an engine frame (not shown), a crankshaft (not shown), and a generator shaft (not shown) of an alternator. The pulley structure 21 shown in FIG. 6 is installed on the generator shaft of the alternator, and rotates when engine power is transmitted through a crankshaft and a belt (not shown). The pulley structure 21 includes a pulley 22 formed in a cylindrical shape, and an uneven surface 22 a capable of transmitting a driving force from the engine by winding the belt on the outer peripheral surface of the pulley 22. Is provided.

  A bearing 24 is arranged on the inner circumference of one end of the pulley 22 in the axial direction, and a bearing 25 is arranged on the inner circumference of the other end in the axial direction. The hub structure 23 is supported by the bearings 24 and 25 so as to be rotatable relative to the pulley 22, and the hub structure 23 is disposed in the inner space of the pulley 22 and concentrically with the pulley 22.

  Stop members 31, 32 for fixing the bearing 24 and the bearing 25 so as not to be detached are fitted on the outer periphery of the hub structure 23, respectively. Further, the shaft hole 23a of the hub structure 23 is formed so as to be able to fix a power generation shaft (not shown) of the alternator.

  In the present embodiment, ball bearings are used as the bearing 24 and the bearing 25. However, the present invention is not limited to this, and the configuration may be simplified by employing, for example, dry metal.

  A spring accommodating chamber 26 is formed by the pulley 22, the hub structure 23, and the bearings 24 and 25, and a coil spring 27 is accommodated in the spring accommodating chamber 26. The coil spring is formed by spirally winding a linear body mainly made of metal. A first winding attachment region 27 a including one end is formed at one end of the coil spring 27. The first winding region 27a includes the one end, and has a configuration in which the linear body extends toward the other end while being curved with substantially the same curvature.

  In the present embodiment, the first housing groove 22b as shown in FIG. 6 is provided on the inner surface of the pulley 22 facing the spring housing chamber 26, and the circumferential surface on the central axis side facing the radial direction in the groove 22b is a spring. The coil spring 27 is mounted so that the guide surface 22d is in contact with the inner peripheral surface of the first winding attachment region 27a and the spring guide surface 22d. Further, in this embodiment, the first receiving groove 22b is provided with a region in which the cross section in the radial direction of the rotation axis is an arc groove shape, and the spring stopper surface that can face the one end of the coil spring 27 in the circumferential direction in the arc groove. 22c is provided. An example thereof is shown in FIGS. 7 and 8 which are AA sectional views and BB sectional views of FIG. The one end of the coil spring 27 and the spring stopper surface 22c are in a state where the first winding region 27a is received in the first receiving groove and the inner peripheral surface of the first winding region 27a is in contact with the spring guide surface 22d. The structure is such that it faces in the circumferential direction (see FIG. 8).

  In the present embodiment, the central angle θ of the portion excluding the groove of the circle including the arc groove is set to about 90 degrees in the region having the arc groove shape in the cross section. However, the present invention is not limited to this range. A spring stopper surface 22c is formed on the two boundaries between the portion excluding the groove and the groove, facing the one end of the coil spring 27. Further, the spring stopper surface 22c needs to be strong enough to support the one end of the spring during the rotational movement of the pulley structure, and the coil spring 27 can be stably accommodated in the receiving groove 22b without tilting. It is also necessary to do. Therefore, it is desirable that the center angle θ is as small as possible. Further, since the spring stopper surface 22c needs to have an area enough to support the one end of the coil spring 27 facing in the circumferential direction, the region in which the cross section has an arc groove shape has a length in the rotation axis direction. However, at least the thickness of the linear body constituting the coil spring 27 is required in the rotational axis direction.

  Further, the width of the first accommodation groove 22b in the radial direction of the rotating shaft needs to be large enough to accommodate the linear body constituting the coil spring 27, but the upper limit is not particularly limited here.

  Further, in the present embodiment, the other end portion 27b is obtained by locking the end portion extending radially outward or inward of the other end and press-fitting into the accommodation groove near the other end portion 27b of the coil spring 27. Is fitted and fixed to the hub structure.

  As described above, the coil spring 27 is disposed inside the spring accommodating chamber 26 substantially concentrically with the pulley structure 21. The pulley 22 and the hub structure 23 are elastically connected via a coil spring 27.

  Next, a contact state between the first winding attached region 27a of the coil spring 27 and the spring guide surface 22d will be described.

  When the pulley 22 is rotating at a rotational speed equal to or higher than the hub structure 23 in the direction in which the coil spring 27 is tightened represented by the arrow W in FIG. 8, the first winding region 27 a of the coil spring 27 is a spring. By holding the guide surface 22d, the spring guide surface 22d is stationary with respect to the first winding attachment region 27a, and on the other hand, the pulley 22 is moved in the direction in which the coil spring 27 is tightened (arrow W). When rotating at a rotational speed less than that, the one end of the coil spring 27 is pressed by the spring stopper surface 22c in the direction in which the coil spring 27 is wound and loosened (arrow Y), whereby the spring guide surface 22d is The coil spring 2 is moved so as to move substantially freely in the circumferential direction with respect to the winding region 27a. There is mounted on the spring guide surface 22d. In order to achieve such a contact state, the inside diameter of the coil spring 27 when taken out from the spring accommodating chamber 26 is appropriately set, or a viscous fluid having an appropriate viscosity between the winding region 27a and the spring guide 22d. A method such as coating is used.

  Next, the operation of the pulley structure 21 configured as described above will be described.

  First, when the pulley 22 and the hub structure 23 are not rotating, the driving force is transmitted by the belt and the pulley 22 starts to rotate in the direction indicated by the arrow W in FIG. The rotational speed in the arrow W direction is higher than that of the structure 23. In this state, the first winding attachment region 27a is stationary with respect to the spring guide surface 22d, and the spring guide surface 22d and the first winding attachment region 27a rotate in the arrow W direction at the same rotational speed. If the rotation is continued as it is, the pulley 22 rotates due to the gripping action between the first winding attached region 27 a of the coil spring 27 and the spring guide surface 22 d and the fitting and fixing of the other end 27 b and the hub structure 23. The hub structure 23 that is elastically transmitted to the hub structure 23 via the coil spring 27 and has been transmitted to the hub structure 23 also starts to rotate. At this time, the pulley 22 and the hub structure 23 rotate while the coil spring 27 is tightened, and when the coil spring 27 is tightened to the limit, the pulley 22 and the hub structure 23 move in the direction of arrow W at the same rotational speed. Rotate. Even in this state, the first winding attachment region 27a is stationary with respect to the spring guide surface 22d.

  In the above state, in addition to the initial gripping force of the first winding region 27a, a tightening force is generated on the spring guide surface 22d by the coil spring 27 in the direction indicated by the arrow X in FIG. The frictional force for holding the spring guide surface 22d is strengthened. For this reason, even when the rotational speed is increased, the first winding attachment portion 27a is less likely to slide with respect to the spring guide surface 22d.

  In addition, during the rotational movement in the state where the rotational speed of the pulley 22 in the arrow W direction is equal to or higher than the hub structure 23 as described above, the intermediate portion between one end and the other end of the coil spring is from the beginning. In this state, elastic rotational energy in the direction of loosening is stored in the coil spring 27, and the pulley 22 and the hub structure 23 have instantaneous relative elastic rotational motion in opposite directions. It can be done.

  Here, when the rotational speed of the crankshaft is changed and the belt speed is suddenly reduced, a force in the direction of arrow Y in which the coil spring 27 is wound around the hub structure 23 is applied to the pulley by the belt. As described above, the pulley 22 and the hub structure 23 can be instantaneously and relatively elastically rotated in the opposite directions by the elastic force of the coil spring 27. Therefore, when the belt speed rapidly decreases, the pulley 22 and the hub structure 23 continue to rotate with inertia. The pulley 22 can rotate independently in the arrow Y direction with respect to the hub structure 23. At that time, the spring stopper surface 22c presses the one end of the spring 27 (in the direction of arrow Z in FIG. 8), so that the coil spring can be efficiently produced without causing a slip between the coil spring 27 and the pulley 22. 27 is loosened. Further, in this state, the first winding attachment region 27a has moved about 5 degrees (angle) in the circumferential direction from the stationary state with respect to the spring guide surface 22d. As a result, the squealing of the belt is suppressed by gently absorbing the crankshaft rotational fluctuation, and the belt can be prevented from being worn.

  In this embodiment, a state in which both the pulley and the hub structure rotate at the same rotational speed and a state in which the pulley rotates at a lower rotational speed than the hub structure in the same direction can be switched using a coil spring. It can be. Here, as described above, in the conventional pulley structure, the coil spring is housed in the arc-shaped housing groove provided in the rotating body, and the end portion extending radially outward or inward is provided. As a result, it is fixed to the rotating body, and as a result, stress concentration occurs in the curved part of the extension part due to the relative rotational movement between the pulley and the alternator hub structure due to rotational fluctuation, and the crank There is a possibility that the end portion where the coil spring is locked is subject to fatigue failure due to local repeated stress generated every time the shaft rotates. On the other hand, in this embodiment, the coil spring and the pulley are connected by forming the winding region 27a without bending the end portion of the coil spring. For this reason, fatigue failure in the first attached region of the coil spring and pulley damage in the vicinity thereof are less likely to occur.

  Further, by using a coil spring, the allowable relative angular displacement can be made larger than that of an annular rubber or the like for the structural reason of winding the spring wire in a spiral shape. Therefore, the allowable relative angular displacement between the pulley 22 and the hub structure 23 can be increased, and the rotational fluctuation can be absorbed efficiently.

  Moreover, it is preferable that the pulley 22 is actively reduced in weight, for example, by providing a lightening part. As a result, the rotational inertia moment of the pulley 22 can be reduced, so that the belt tension required to maintain the speed at a certain point of the pulley body 22a at the speed of the belt can be relaxed. Therefore, generation of force exceeding the static frictional force between the pulley body 22a and the belt can be suppressed, so that the belt is not worn and the life can be extended.

  Further, it is preferable to employ a light alloy such as aluminum as the material of the pulley 22. As a result, the rotational moment of inertia of the pulley 22 can be further reduced, and there is an effect that the life of the belt can be extended in the same manner as the effect of weight reduction by the above-described thinning.

  Furthermore, you may change the cross-sectional shape of a coil spring. For example, it is known that the following effects can be obtained by comparing a coil spring having a circular cross section with a rectangular coil spring having a rectangular cross section. That is, with the same relative angular displacement, the same number of turns, and the same spring constant, the maximum tensile (compression) stress generated in the latter coil spring can be reduced to about 70%, while it occurs at the same relative angular displacement. If the maximum tensile (compression) stress is the same and the spring constant is the same, the latter required number of turns is 70%. For the above reason, a square coil spring may be adopted, but the present invention is not limited to this, and the cross-sectional shape of the coil spring may be, for example, a circle.

  In the present embodiment, the end of the coil spring 27 is accommodated in the first accommodation groove 22b. Thus, by accommodating the end of the coil spring 27 in the first housing groove 22b, the coil spring 27 can be reliably and straightly installed without being tilted. That is, if the coil spring 27 is installed with an inclination, an excessive force is likely to be applied to a part of the coil spring 27 due to rotational fluctuation applied to the pulley structure 21, and the coil spring 27 is likely to be damaged. In this respect, in the present embodiment, since the first mounting groove 22b can reliably avoid the attachment direction of the coil spring 27 from being inclined, the rotational fluctuation applied to the pulley structure 21 can be uniformly received by the entire spring wire. The life of the coil spring 27 can be extended.

  In this embodiment, the rotational driving force from the power output side, for example, the crankshaft of the engine, is applied to the pulley 22 and the pulley 22 transmits the rotational driving force to the hub structure 23. In other words, the hub structure 23 may be provided with a rotational driving force on the power output side so that the hub structure 23 transmits the rotational driving force to the pulley 22. In this case, the rotational driving force is transmitted from the hub structure 23 to the pulley 22 via the coil spring 27, and power is output from the pulley 22 via the belt.

  In that case, when the hub structure 23 is rotating at a rotational speed higher than that of the pulley 22 in the direction in which the coil spring 27 is tightened (direction Y in FIG. 8), the first attached region 27 a of the coil spring 27. By holding the spring guide surface 22d, the hub structure 23 is moved in the direction (direction Y) in which the spring guide surface 22d is stationary with respect to the first winding attachment region 27a and the coil spring 27 is wound. Is rotating at a rotational speed lower than that of the pulley 22, the one end of the coil spring 27 is pressed by the spring stopper surface 22c in the direction in which the coil spring 27 is wound and loosened (arrow Y), whereby the spring guide surface 22d. So that the coil moves substantially freely in the circumferential direction with respect to the first winding attachment region 27a. Ring 27 is mounted on the spring guide surface 22d.

  In this embodiment, one end of the coil spring 27 is attached to the spring guide surface 22d of the pulley 22 and the other end is fitted and fixed to the hub structure 23. A guide surface may be provided, one end of the coil spring 27 may be attached to the spring guide surface, and the other end may be fitted and fixed to the pulley 22.

  When the rotational speed of one of the first rotating body (pulley 22) and the second rotating body (hub structure 23) in the direction in which the coil spring 27 is tightened is less than that of the other, the linear body is extended. With respect to the present direction, the coil spring 27 preferably has a region that does not contact either the first rotating body (pulley 22) or the second rotating body (hub structure 23). According to this, both the first rotating body (pulley 22) and the second rotating body (hub structure 23) rotate at the same rotational speed, and one of the transmission forces is transmitted at a lower rotational speed than the other. At the time of the state transition between the rotating state, the coil spring 27 suppresses a rapid change in the rotational speed of each rotating body, so that the damage to each rotating body is less likely to occur.

  In the present embodiment, the case where the pulley structure 21 is provided in the hub structure of the alternator has been described. However, the present invention is not limited thereto, and for example, the pulley of the present invention may be installed on the compressor shaft of the air conditioner of an automobile. . Further, the application of the pulley structure of the present invention other than the vehicle equipment is not hindered, and the pulley structure of the present invention can be installed and used in various rotation transmission systems.

(Third embodiment)
Next, based on FIGS. 9-14, the pulley structure 11 which concerns on 3rd Embodiment of this invention is demonstrated. In the third embodiment, in principle, the same reference numerals are given to members similar to the constituent members of the second embodiment.

  The pulley structure according to the third embodiment will be described below with a focus on differences from the pulley structure according to the second embodiment.

  FIG. 9 is a longitudinal sectional view of the pulley structure 11 according to the third embodiment of the present invention. The 1st volume attachment area | region 17a of the coil spring 17 which concerns on 3rd Embodiment is comprised from the said linear body whose winding number is one or more turns. Therefore, the length of the spring guide surface 12d provided on the rotating body 12 in the pulley structure rotating shaft direction is required to be at least as long as it abuts the first winding attachment region 17a. In other words, in the present embodiment, the length (groove depth) of the coil spring housing groove 12b in the pulley structure rotation axis direction is longer than the length in contact with the first winding attachment region 17a. In this way, by setting the number of windings in the winding region 17a to 1 or more, the gripping force applied to the spring guide surface 12d by the first winding region 17a increases, so that the coil spring slides with respect to the spring guide surface 12d. And the reliability is improved.

  FIGS. 10A and 10B show a DD cross-sectional view of the pulley structure shown in FIG. 9 with the coil spring 17 taken out from the receiving groove 12b, and the coil spring 17 taken out from the receiving groove 12b. FIG. 11 is a sectional view taken along the line DD of FIG. 9, and FIG. 11 is a sectional view taken along the line DD of the pulley structure shown in FIG. When the coil spring 17 is taken out from the spring accommodating chamber 16, the inner diameter (deo in FIG. 10B) of the first winding attachment region 17a of the coil spring 17 is the outer diameter of the spring guide surface 12d (FIG. 10A). The structure is smaller than de). This increases the gripping force applied to the spring guide surface 12d by the first winding region (the gripping force increases in the X direction in FIG. 11), so that the coil spring is less likely to slide with respect to the spring guide surface. Reliability is improved.

  The coil spring 17 is formed with a second winding attachment region 17b including the other end with respect to one end on the pulley 12 side. The second attached region 17b includes the other end and is configured to extend toward the one end while being curved with the same linear curvature.

  In the present embodiment, the hub structure 13 is provided with a second receiving groove 13b, and the circumferential surface of the groove 13b facing the radial direction on the central axis side is a spring guide surface 13d, and the second winding region 17b is a spring. A coil spring 17 is mounted so as to come into contact with the guide surface 13d. Also in this embodiment, similarly to the pulley side of the first embodiment, the second receiving groove 13b is provided with a portion whose cross-sectional shape is an arc groove, and can be opposed to the other end of the coil spring 17 in the circumferential direction. A spring stopper surface 13c is provided. More specifically, as shown in FIG. 12, which is a cross-sectional view taken along the line CC of FIG. 9, the coil winding spring 17b is accommodated in the second accommodation groove 13b and in contact with the spring guide surface 13d. 17 has a structure in which one end of the spring 17 faces the spring stopper surface 13c.

  As a result, not only the first winding region 17a in the pulley but also the second winding region 17b of the coil spring is less likely to cause fatigue failure or damage to the rotating body in the vicinity thereof.

  Similarly to the first winding region 17a, the second winding region 17b is composed of the linear body having one or more turns, and the length of the coil spring housing groove 13b in the pulley structure rotation axis direction is long. The length (groove depth) is equal to or longer than the amount in contact with the second winding attachment region 17b. Further, when the coil spring 17 is taken out from the spring accommodating chamber 16, the inner diameter of the second auxiliary region 17b is smaller than the outer diameter of the spring guide surface 13d.

  Moreover, in 3rd Embodiment, it is a spring accommodating chamber, Comprising: The space 16a between the outer peripheral surface of the coil spring 17 except a winding area | region and the inner peripheral surface of the pulley 12 which opposes is ensured. When the rotational speed of the pulley 12 in the direction in which the coil spring 17 is wound (direction W in FIG. 11) is smaller than that of the hub structure 13, that is, the pulley 12 is wound around the hub structure 13. Even when the coil spring 17 is wound and loosened when rotating in the loosening direction (direction Y in FIG. 11), the coil 16 is secured by securing the space 16a of the spring accommodating chamber even if the diameter of the coil spring 17 becomes larger than the initial diameter. A region where the spring 17 does not contact either the pulley 12 or the hub structure 13 is formed. Thereby, the state transition between the state where both the pulley 12 and the hub structure 13 rotate at the same rotational speed and the state where the pulley 12 to which the driving force is transmitted rotates at a rotational speed smaller than that of the hub structure 13. Sometimes, the coil spring suppresses a rapid change in the rotational speed of each rotating body, so that the damage to each rotating body is less likely to occur. FIG. 13 shows an example of a cross-sectional view of the pulley structure in a state where the coil spring according to the third embodiment of the present invention is wound and loosened.

  In the above embodiment, the space 16a between the outer peripheral surface of the coil spring 17 other than the winding region and the inner peripheral surface of the pulley 12 facing the spring accommodating chamber is ensured. Thus, a space 16b between the inner peripheral surface of the coil spring 17 other than the winding region and the outer peripheral surface of the hub structure 13 facing the space 16b may be secured.

  In the pulley structure 11 according to this embodiment, when the rotational speed of the pulley 12 in the direction (direction W) in which the coil spring 17 is tightened is equal to or higher than the rotational speed of the hub structure 13, the coil spring is attached. Since the portion excluding the region is in a state of being tightened from the beginning, the rotational energy in the loosening direction is stored, and the pulley 12 and the hub structure 13 instantaneously rotate in the opposite directions. Can be done. Here, when the coil spring 17 is tightened, the space of the spring accommodating chamber 16b is secured, so that the coil spring 17 can be tightened to a smaller diameter and stores stronger rotational energy in the winding loosening direction. be able to. FIG. 14 shows an example of a cross-sectional view of the pulley structure in a state where the coil spring according to the third embodiment of the present invention is wound.

  In this embodiment, the rotational driving force from the power output side, for example, the crankshaft of the engine is applied to the pulley 12 and the pulley 12 transmits the rotational driving force to the hub structure 13. Alternatively, a rotational driving force on the power output side may be applied to the hub structure 13 so that the hub structure 13 transmits the rotational driving force to the pulley 12. In this case, the rotational driving force is transmitted from the hub structure 13 to the pulley 12 via the coil spring 17 and power is output from the pulley 12 via the belt.

(Fourth embodiment)
Next, based on FIG.15 and FIG.16, the pulley structure 111 which concerns on 4th Embodiment of this invention is demonstrated. As for the figure, in the fourth embodiment, members similar to the constituent members of the second and third embodiments described above are given the same reference numerals in principle.

  The pulley structure according to the fourth embodiment will be described below with a focus on differences from the pulley structure according to the second and third embodiments.

  FIG. 15 is a longitudinal sectional view of a coil spring 117 according to the fourth embodiment. Moreover, Fig.16 (a) shows the principal part of the longitudinal cross-sectional view of the pulley structure 111 which concerns on 4th Embodiment of this invention, FIG.16 (b) is EE of Fig.16 (a). It is sectional drawing. FIG. 16 shows a part necessary for the explanation, not the cross section itself. FIG. 16 shows only the hub 113 side (second winding attachment region 117b side) of the pulley structure 111, but the pulley 112 side (first winding attachment region 117a side) is also described on the hub 113 side. It is omitted because it is sufficient to be represented by.

  As shown in FIG. 15, the coil spring 117 according to the fourth embodiment has an inner diameter deo of the first winding region 117a and the second winding region 117b in a state of being taken out from the spring housing chamber of the pulley structure 111. The structure is smaller than the inner diameter dm of the intermediate region 117c of the coil spring 117 that is separated from the first winding region 117a and the second winding region 117b. Similarly to the third embodiment, the inner diameter deo of the first winding attachment region 117a and the second winding attachment region 117b is such that the pulley side spring guide surface (not shown) and the hub 113 side spring guide surface 113d are It is smaller than the outer diameter de (see FIG. 16). Also, as shown in FIGS. 16A and 16B, the inner diameter dm in the intermediate region 117c is larger than de. As described above, the relationship of dm> de> deo is established for the dm, de, and deo.

  In the pulley structure 111, the inner diameter of the coil spring 117 is increased from the winding region to the intermediate region in the transition region 117t formed by one turn between the winding region 117b and the intermediate region 117c of the coil spring. Increases from de to dm (see FIGS. 16A and 16B). Therefore, the inner peripheral surface of the coil spring 117 is separated from the spring guide surface 113d in the transition region 117t, and they are not in contact with each other.

  Here, if there is a portion where the spring guide surface and the coil spring are in local contact, that is, if there is a portion where the inner peripheral surface of the coil spring is in contact with the spring guide surface only in a part of its width, Each time, stress concentration occurs in the part, which may cause harmful wear and breakage of the coil spring. However, since the inner peripheral surface of the coil spring 117 is separated from the spring guide surface 113d in the transition region 117t as in this embodiment, local contact can be avoided, so that the coil spring Wear and breakage in the transition region can be suppressed.

  As described above, by adopting the structure of the pulley structure 111 of the fourth embodiment, it is possible to suppress the coil spring from being worn or damaged in the transition region. Further, a different diameter coil spring such as the coil spring 111 is already technically easy to manufacture, and the manufacturing itself is not costly.

  As described above, since the fourth embodiment is configured as described above, the gripping force applied to the spring guide surface by the first winding region increases, so that the coil spring can slide with respect to the spring guide surface. Less and improves reliability. Furthermore, it is possible to suppress the coil spring from being worn or damaged in the transition region.

  Further, for example, in the above-described embodiment, the first winding area and the second winding area have the same inner diameter, and the hub-side and pulley-side spring guide surfaces have the same outer diameter. These may be different from each other as long as the above-described magnitude relationship is satisfied. Furthermore, although the number of turns in the transition region of the coil spring is assumed to be one turn in the above embodiment, it is not limited to this.

(Fifth embodiment)
Next, FIG. 17 is a longitudinal sectional view of a pulley structure according to a fifth embodiment of the present invention. An automobile internal combustion engine (not shown) includes an engine frame (not shown), a crankshaft (not shown), and a generator shaft (not shown) of an alternator. The pulley structure 61 shown in FIG. 17 is installed on the generator shaft of the alternator, and rotates when engine power is transmitted via a crankshaft and a belt (not shown). This pulley structure 61 has a pulley 62 formed in a cylindrical shape. On the outer peripheral surface of the pulley 62, there is an uneven surface 62a that can transmit the driving force from the engine by winding the belt. Is provided.

  A bearing 64 is disposed on the inner circumference of one end of the pulley 2 in the axial direction, and a bearing 65 is disposed on the inner circumference of the other end in the axial direction. The hub structure 63 is supported by the bearing 64 and the bearing 65 so as to be rotatable relative to the pulley 62, and the hub structure 63 is disposed concentrically with the pulley 62 in the inner space of the pulley 62. Further, the shaft hole 63a of the hub structure 63 is formed so as to be able to fix a power generation shaft (not shown) of the alternator.

  In the present embodiment, dry metal and ball bearings are used as the bearing 64 and the bearing 65, respectively, but the present invention is not limited to such a configuration.

  The pulley 62, the hub structure 63, the bearing 64, and the bearing 65 form a spring accommodating chamber 66, and a coil spring 67 is accommodated in the spring accommodating chamber 66. The coil spring is a metal linear body wound spirally. Further, at both ends of the coil spring 67, a first winding attachment region 67a including one end and a second winding attachment region 67b including the other end are formed. Here, the first winding attached region 67a includes one end of the coil spring 67, and the linear body is curved with substantially the same curvature and extends toward the other end. The second winding attached region 67b includes the other end of the coil spring 67 and has a configuration in which the linear body extends toward one end while being curved with substantially the same curvature. Each winding region is composed of a linear body having approximately one winding. Further, the inner diameter of the coil spring 67 is uniform over the entire region including the first winding attached region 67a and the second winding attached region 67b in the state of being taken out from the spring accommodating chamber 66.

  In the spring accommodating chamber 66, the space between the outer peripheral surface of the intermediate region 67 c of the coil spring 67 and the inner peripheral surface of the pulley 62 when the coil spring 67 is mounted on the pulley structure 61, and the middle of the coil spring 67. A space between the inner peripheral surface of the region 67c and the outer peripheral surface of the hub structure 63 is included.

  In the pulley structure 61 according to the present embodiment, the pulley 62 is provided with an inner peripheral side spring guide surface 62d facing the spring accommodating chamber 66 and directed radially outward, and the first winding region 67a. A coil spring 67 is mounted so that the inner peripheral surface comes into contact with the inner peripheral spring guide surface 62d. The hub structure 63 is provided with an inner peripheral side spring guide surface 63d facing the storage chamber 66 and directed radially outward, and the inner peripheral surface of the second winding region 67b is the inner peripheral spring guide surface. A coil spring 67 is mounted so as to come into contact with 63d.

  As described above, the coil spring 67 is disposed inside the spring accommodating chamber 66 substantially concentrically with the pulley structure 61. The pulley 62 and the hub structure 63 are elastically connected via a coil spring 67.

  Next, the structure of the inner peripheral spring guide surfaces 62d and 63d of the pulley structure 61 and the mounting state of the coil spring 67 will be described with reference to FIG. FIG. 18A is a view showing a main part of a cross-sectional view (corresponding to the FF cross-sectional position of FIG. 17) of the pulley structure according to the fifth embodiment of the present invention. FIG. 18B is a view showing a main part of the GG sectional view of FIG. FIG. 18 shows only the main part necessary for the explanation, not the cross section itself. FIG. 18 shows only the structure on the side of the first volume attachment region 67a, but the description on the side of the second volume attachment region 67b is also omitted because it is sufficient to be representative in the description of the side of the first volume attachment region 67a. It is.

  As shown in FIGS. 18A and 18B, a continuous first spiral path 62f with the rotation axis of the pulley 62 and the hub structure 63 as a central axis is formed on the inner circumferential spring guide surface 62d. The outer diameter of the first spiral path 62f is constant in the portion corresponding to the first winding attached region 67a and in the portion corresponding to the first transition region 67t continuous to the first winding attached region 67a. The outer diameter decreases along the direction of the arrow M in FIG. 18B along the first spiral path 62f. Further, the intermediate region 67c of the coil spring and the inner peripheral spring guide surface 62d are not in contact with each other. Further, in the state where the coil spring 67 is taken out from the spring accommodating chamber 66, the inner diameters of the first winding attached region 67a and the first transition region 67t are the same as the first winding attached region 67a and the first transition region 67t. It is smaller than the outer diameter of the corresponding part of one spiral path 62f. Therefore, the first winding region 67a and the first transition region 67t of the coil spring 67 are spirally shaped so that there is no gap in accordance with the shape of the inner peripheral spring guide surface 62d whose outer diameter changes. The inner diameter of the spring guide surface 62d is mounted while decreasing its inner diameter continuously in the direction of M. Further, since the pitch of the first spiral path 62f of the inner peripheral side spring guide surface 62d and the pitch of the coil spring 67 are equal, the coil spring 67 has the first winding region 67a and the first transition region 67t. Everywhere inside, it is within the width of the first spiral path 62f. The same applies to the second winding attached region 67b, the second transition region 67u continuous to the second winding attached region 67b, the inner peripheral spring guide surface 63d, and the second spiral path 63f.

  In the present embodiment, the pulley 62 has a spring stopper surface 62c facing the one end of the coil spring 67 on the first winding attached region 67a side in the circumferential direction, and the hub structure 63 has the second winding attached region 67b. A spring stopper surface (not shown) facing the other end of the side is provided. An example thereof is shown in FIGS. 19 and 20, which are the HH sectional view and the II sectional view of FIG. As shown in FIG. 20, one end of the coil spring 67 and the spring stopper surface 62 c face each other in the circumferential direction in a state where the inner peripheral surface of the first winding attachment region 67 a is in contact with the inner peripheral spring guide surface 62 d. It has become. Although not shown, the same applies to the second winding attachment region 67b side, and the coil spring 67 is in a state where the inner peripheral surface of the second winding attachment region 67b is in contact with the inner peripheral spring guide surface 63d. The other end and a spring stopper surface (not shown) are opposed to each other in the circumferential direction.

  FIG. 19 is a cross-sectional view at a position including the spring stopper surface 62c. However, when the spring stopper surface 62c is provided, the inner peripheral spring guide surface 62d is blocked as shown in FIG. An arcuate area is created. In the present embodiment, in this region, the central angle θ of the portion blocking the inner peripheral spring guide surface 62d is set to about 90 degrees, but is not limited to this range. Further, the area of the spring stopper surface 62c is preferably at least the area of one end of the coil spring 67 so that the pulley structure 61 can support one end of the coil spring 67 during the rotational movement. Further, in order for the coil spring 67 to stably come into contact with the inner circumferential side spring guide surface 62d in the above region, it is desirable that the center angle θ is as small as possible.

  Next, a contact state between the first and second winding attached regions 67a and 67b of the coil spring 67 and the inner peripheral spring guide surfaces 62d and 63d will be described with reference to FIG.

  When the pulley 62 is rotating in the direction in which the coil spring 67 is tightened (direction of arrow R in FIG. 20) at a rotational speed higher than the hub structure 63, the first winding region 67a of the coil spring 67 is on the inner peripheral side. A coil spring 67 is mounted on the inner circumferential spring guide surface 62d so that the inner circumferential spring guide surface 62d is stationary relative to the first winding attachment region 67a by gripping the spring guide surface 62d. On the other hand, when the pulley 62 is rotating at a rotational speed lower than that of the hub structure 63 in the direction in which the coil spring 67 is tightened, the inner peripheral spring guide surface 62d is moved from the stationary state to the first winding region 67a. The coil spring 67 is rotated by about 5 degrees (angle) in the direction of the arrow T, and thereafter, one end of the coil spring 67 is pressed by the spring stopper surface 62c in the direction in which the coil spring 67 is wound and loosened (in the direction of the arrow T). The coil spring 67 is mounted on the inner circumferential spring guide surface 62d so that the spring guide surface 62d is stationary relative to the first winding attachment region 67a.

  Although not shown, the second winding region 67b side is the same as the first winding region 67a side, and the pulley 62 rotates at a rotational speed higher than the hub structure 63 in the direction in which the coil spring 67 is tightened. When the second winding attached region 67b of the coil spring 67 grips the inner peripheral spring guide surface 63d, the inner peripheral spring guide surface 63d is stationary with respect to the second winding attached region 67b. A coil spring 67 is mounted on the inner peripheral spring guide surface 63d. On the other hand, when the pulley 62 is rotating at a rotational speed lower than the hub structure 63 in the direction in which the coil spring 67 is tightened, the inner peripheral spring guide surface 63d is moved from the stationary state to the second winding region. It rotates about 5 degrees (angle) in the direction of arrow R with respect to 67b, and then the other end of the coil spring 67 is pressed by the spring stopper surface 62c in the direction in which the coil spring 67 is wound and loosened, while the inner peripheral spring guide surface A coil spring 67 is mounted on the inner peripheral spring guide surface 62d so that 63d is stationary with respect to the second winding attachment region 67b.

  In order to achieve the contact state as described above, the inner diameter of the coil spring 67 is smaller than the minimum inner diameter of the inner peripheral spring guide surfaces 62d and 63d in a state where the coil spring 67 is removed from the spring accommodating chamber 66.

  Next, the operation of the pulley structure 61 configured as described above will be described.

  First, in a state immediately after the pulley 62 and the hub structure 63 are not rotating, and immediately after the driving force is transmitted by the belt and the pulley 62 starts to rotate in the direction indicated by the arrow R in FIG. However, the rotational speed in the arrow R direction is larger than that of the hub structure 63. In this state, the first winding attachment region 67a is stationary with respect to the inner peripheral spring guide surface 62d, and the inner peripheral spring guide surface 62d and the first winding attachment region 67a move in the direction of arrow R at the same rotational speed. It is rotating. If the rotation continues, the gripping action between the first winding attached region 67a of the coil spring 67 and the inner peripheral spring guide surface 62d, and the second winding additional region 67b on the other end side and the inner peripheral spring guide surface are provided. The rotation of the pulley 62 is elastically transmitted to the hub structure 63 via the coil spring 67 by the gripping action between the hub structure 63 and the hub structure 3 to which the rotation is transmitted starts to rotate. At this time, the pulley 62 and the hub structure 63 rotate while the coil spring 67 is tightened. When the coil spring 7 is tightened to the limit, the pulley 62 and the hub structure 63 move in the direction of arrow R at the same rotational speed. Rotate. In this state, the first winding attachment region 67a and the second winding attachment region 67b are stationary with respect to the inner peripheral spring guide surfaces 62d and 63d.

  In such a state, in addition to the gripping force with respect to the inner peripheral side spring guide surface 62d of the initial first winding attachment region 67a, the inner peripheral side spring guide surface by the coil spring 67 in the direction indicated by the arrow S in FIG. A tightening force for 62d is generated, and a frictional force for the coil spring 67 to hold the inner peripheral spring guide surface 62d is strengthened. The same applies to the inner peripheral side spring guide surface 63 d on the other end side of the coil spring 67. Therefore, even if the rotational speed is increased, the first winding attachment region 67a and the second winding attachment region 67b hardly slide with respect to the inner peripheral spring guide surfaces 62d and 63d. In this state, the inner peripheral spring guide surfaces 62d and 63d are stationary with respect to the first winding attachment region 67a and the second winding attachment region 67b, respectively.

  Further, during the rotational movement in the state where the rotational speed of the pulley 62 in the direction of the arrow R is equal to or higher than the hub structure 63 as described above, the intermediate region 67c of the coil spring 67 is tightened from the beginning. By being in the state, the elastic rotational energy in the winding loosening direction is stored in the coil spring 67, and the pulley 62 and the hub structure 63 can instantaneously perform the relative elastic rotational motion in the opposite directions. Yes. In this embodiment, the space between the intermediate region 67c of the coil spring 67 and the hub structure 63 is secured in the spring accommodating chamber 66, so that the coil spring 67 can be tightened to a smaller diameter. Yes, it can store stronger elastic rotational energy in the direction of loosening.

  Here, when the rotational speed of the crankshaft is changed and the belt speed rapidly decreases, a force in the direction of arrow T in which the coil spring 67 is wound and loosened with respect to the hub structure 63 is applied to the pulley 62 by the belt. As described above, the pulley 62 and the hub structure 63 can be instantaneously and relatively elastically rotated in the opposite directions by the elastic force of the coil spring 67, so that the pulley 62 and the hub structure 63 can rotate with inertia when the belt speed rapidly decreases. When the coil spring 67 is loosened around the hub structure 63 that continues, the pulley 62 can rotate independently in the arrow T direction. Here, from the stationary state, the inner peripheral spring guide surface 62d rotates about 5 degrees (angle) with respect to the first winding attachment region 67a (in the direction of arrow T in FIG. 23), and thereafter the spring stopper surface 62c. As a result, one end of the coil spring 67 is pressed (in the direction of arrow U in FIG. 20), and the coil spring 67 is efficiently wound and loosened without causing slippage between the coil spring 67 and the pulley 62. Similarly, the other end of the coil spring 67 is pressed by the effect of the spring stopper surface on the other end side, and the coil spring 67 is efficiently wound and loosened without causing a slip between the coil spring 67 and the pulley 63. I will. In this state, the inner peripheral spring guide surfaces 62d and 63d are stationary with respect to the first winding attachment region 67a and the second winding attachment region 67b, respectively.

  As a result, belt squeal is suppressed by efficiently absorbing fluctuations in the crankshaft rotation, and belt wear can be prevented. Moreover, the influence on the hub structure 63 and the power generation shaft due to the crankshaft rotation fluctuation can be reduced.

  In this embodiment, the space between the intermediate region 67 c of the coil spring 67 and the pulley 62 is secured in the spring accommodating chamber 66, so that the coil spring 67 can be attached to either the pulley 62 or the hub structure 63. An area where no contact is made. As a result, the coil spring 67 can be wound and loosened larger than the initial inner diameter, and thereby the relative angular displacement between the pulley 62 and the hub structure 63 can be increased. Therefore, the belt squeal is suppressed by efficiently absorbing the rotational fluctuation of the crankshaft, and the belt can be prevented from being worn.

  Here, in the first transition region 67a and the second winding region 67b, and in the transition regions 67t and 67u from the first winding region 67a and the second winding region 67b to the intermediate region 67c of the coil spring, respectively. Since the inner circumferential surface of the coil spring 67 is in contact with the inner circumferential spring guide surfaces 62d and 63d without any gaps, the gap between the inner circumferential spring guide surface and the coil spring as shown in FIG. A portion that makes local contact, that is, a portion in which the inner peripheral surface of the coil spring 7 is in contact with the inner peripheral spring guide surfaces 62d and 63d only in a part in the width direction is eliminated, and stress is applied every time the crankshaft rotates. Since concentration does not occur, harmful wear and breakage of the coil spring 67 can be prevented. Further, in the present embodiment, the coil spring 67 having a uniform inner diameter in the entire region can be used, and since there is no transition region in which the inner diameter is forcibly changed and stress concentration occurs, the coil spring 67 is worn. Can prevent damage.

  As described above, the pulley structure 61 according to the present embodiment allows the inner circumference in the transition regions 67t and 67u between the first winding region 67a and the second winding region 67b, and the intermediate region 67c of the coil spring. Generation of stress concentration due to local contact between the side spring guide surfaces 62d and 63d and the coil spring 67 can be prevented, and harmful wear and breakage of the coil spring can be suppressed. The pulley 62 and the hub structure 63 both rotate at the same rotational speed, and the pulley 62 rotates at a rotational speed smaller than that of the hub structure 63 in the same direction, including one end and linear. A first winding region 67a extending toward the other end while the body is curved with substantially the same curvature, and the linear body is curved toward the one end while being curved with substantially the same curvature. It can be switched using a coil spring 67 having an extended second winding attachment region 67b. Therefore, fatigue failure in the first winding attached region 67a and second winding attached region 67b of the coil spring 67 and damage to the rotating body in the vicinity thereof are less likely to occur.

  Moreover, in this embodiment, the 1st volume attachment area | region 67a and the 2nd volume attachment area | region 67b are comprised from the linear body whose winding number is 1 turn or more. Thus, by setting the number of windings of the winding region 67a and 67b to 1 or more, the gripping force that the first winding region 67a and the second winding region 67b apply to the inner circumferential spring guide surfaces 62d and 63d, respectively. Therefore, the coil spring 67 is less likely to slide with respect to the inner peripheral spring guide surfaces 62d and 63d, and the reliability is improved.

  In the present embodiment, the rotational driving force from the power output side, for example, the crankshaft of the engine is applied to the pulley 62, and the pulley 62 transmits the rotational driving force to the hub structure 63. A structure, that is, a structure in which a rotational driving force on the power output side is applied to the hub structure 63 so that the hub structure 63 transmits the rotational driving force to the pulley 62 may be employed. In this case, the rotational driving force is transmitted from the hub structure 63 to the pulley 62 via the coil spring 67, and power is output from the pulley 62 via the belt.

  In that case, when the hub structure 63 is rotating at a rotational speed higher than that of the pulley 62 in the direction in which the coil spring 67 is tightened (direction of arrow T in FIG. 20), the first attached region of the coil spring 67 The coil spring 67 is mounted on the inner peripheral spring guide surface 62d so that the inner peripheral spring guide surface 62d is stationary with respect to the first winding region 67a by gripping the inner peripheral spring guide surface 62d. Is done. On the other hand, when the hub structure 63 is rotating at a rotational speed lower than the pulley 62 in the direction in which the coil spring 67 is tightened (arrow T direction), the inner peripheral spring guide surface 62d is the first from the stationary state. The coil spring 67 rotates about 5 degrees (angle) in the arrow T direction with respect to the one-winding region 67a, and then one end of the coil spring 67 is pressed by the spring stopper surface 62c in the direction in which the coil spring 67 is wound and loosened (arrow T). The coil spring 67 is mounted on the inner peripheral spring guide surface 62d so that the inner peripheral spring guide surface 62d is stationary with respect to the first winding attachment region. Similarly, the second winding attachment region 67b on the other end side is also mounted on the inner peripheral spring guide surface 63d.

(Sixth embodiment)
Next, a pulley structure 71 according to a sixth embodiment of the present invention will be described below with reference to FIGS. 21 to 23, focusing on differences from the pulley structure according to the fifth embodiment. In addition, in this embodiment, the same part (71, 72, 72a, 72d, 72f, 73, 73a, 73d, 74, 75, 76, 77, 77a-77c, the structural member of said 5th Embodiment, 77t, 77u), respectively in the portions of the reference numerals (61, 62, 62a, 62d, 62f, 63, 63a, 63d, 64, 65, 66, 67, 67a to 67c, 67t, 67u) of the fifth embodiment. The same parts are shown in order, and description of such similar parts may be omitted.

  FIG. 21 is a longitudinal sectional view of a pulley structure 71 according to the sixth embodiment of the present invention. FIG. 22A is a view showing a main part of a cross-sectional view (corresponding to a KK cross-sectional position in FIG. 21) of the pulley structure according to the sixth embodiment of the present invention. FIG. 22B is a view showing a main part of the LL sectional view of FIG. FIG. 22 shows only the main part necessary for the explanation, not the cross section itself. FIG. 22 shows only the structure on the hub 73 side, but the pulley 72 side is also omitted because it is sufficient to be representative in the description of the hub 73 side. 23 is a cross-sectional view taken along line JJ in FIG.

  In the present embodiment, the pulley 72 has an inner peripheral spring guide surface 72d and an outer peripheral spring guide surface 72e facing the spring accommodating chamber 76 and directed radially inward, and the hub structure 73 has An inner peripheral spring guide surface 73d and an outer peripheral spring guide surface 73e facing the spring accommodating chamber 76 and directed radially inward are provided. The groove width between the inner peripheral spring guide surfaces 72d and 73d and the outer peripheral spring guide surfaces 72e and 73e is the smallest as long as it can accommodate the winding regions 77a and 77b of the coil spring 77, respectively. It is the width of. The first winding region 77a of the coil spring 77 is between the inner peripheral spring guide surface 72d and the outer peripheral spring guide surface 72e, and the second winding region 77b is between the inner peripheral spring guide surface 73d and the outer peripheral spring guide surface 72e. Each is mounted between the side spring guide surface 73e. Further, in the present embodiment, a spring stopper surface that faces one end and the other end of the coil spring 77 in the circumferential direction is not provided.

  Next, a contact state between the first and second winding attached regions 77a and 77b of the coil spring 77 and the inner peripheral spring guide surfaces 72d and 73d will be described with reference to FIG.

  When the pulley 72 is rotating in the direction in which the coil spring 77 is tightened (in the direction of arrow R in FIG. 23) at a rotational speed higher than that of the hub structure 73, the first winding region 77a of the coil spring 77 is on the inner peripheral side. The coil spring 77 is mounted on the inner peripheral spring guide surface 72d so that the inner peripheral spring guide surface 72d is stationary relative to the first winding attachment region 77a by gripping the spring guide surface 72d. On the other hand, when the pulley 72 is rotating at a rotational speed less than the hub structure 73 in the direction in which the coil spring 77 is tightened (arrow R), the inner peripheral spring guide surface 72d is the first from the stationary state. After rotating about 5 degrees in the direction of arrow T with respect to the winding region 77a, the first winding region 77a of the coil spring 77 presses the outer peripheral spring guide surface 72e, whereby the first winding of the coil spring 77 is attached. The coil spring 77 is mounted on the inner peripheral spring guide surface 72d so that the region 77a is stationary with respect to the outer peripheral spring guide surface 72e and the coil spring 77 is wound and loosened. Although not shown, the second winding attachment region 77b is similarly attached to the inner peripheral spring guide surface 73d. In order to achieve such a contact state, the inner diameter of the coil spring 77 is smaller than the minimum inner diameter of the inner-side spring guide surfaces 72d and 73d in a state where the coil spring 77 is removed from the spring accommodating chamber 76.

  Next, the operation of the pulley structure 71 configured as described above will be described.

  First, in a state immediately after the pulley 72 and the hub structure 73 are not rotating, and immediately after the driving force is transmitted by the belt and the pulley 72 starts to rotate in the direction indicated by the arrow R in FIG. However, the rotational speed in the arrow R direction is larger than that of the hub structure 73. In this state, the first winding attachment region 77a is stationary with respect to the inner peripheral spring guide surface 72d, and the inner peripheral spring guide surface 72d and the first winding attachment region 77a are in the direction of arrow R at the same rotational speed. It is rotating. If the rotation continues, the gripping action between the first winding attached region 77a of the coil spring 77 and the inner peripheral spring guide surface 72d, and the second winding attached region 77b and the inner peripheral spring guide surface 73d at the other end will be described. , The rotation of the pulley 72 is elastically transmitted to the hub structure 73 via the coil spring 77, and the hub structure 73 to which the rotation is transmitted also starts to rotate. At this time, the pulley 72 and the hub structure 73 are rotating while the coil spring 77 is tightened, and when the coil spring 7 is tightened to the limit, the pulley 72 and the hub structure 73 are moved in the direction of arrow R at the same rotational speed. Rotate. In this state, the first winding attachment region 77a and the second winding attachment region 77b are stationary with respect to the inner peripheral spring guide surfaces 72d and 73d.

  In such a state, in addition to the initial gripping force of the first winding region 77a, a tightening force is generated by the coil spring 77 against the inner peripheral spring guide surface 72d in the direction indicated by the arrow S in FIG. The frictional force for the coil spring 77 to hold the inner peripheral spring guide surface 72d is reinforced. The same applies to the inner peripheral spring guide surface 73d on the other end side of the coil spring 77. Therefore, even if the rotational speed is increased, the first winding attachment region 77a and the second winding attachment region 77b hardly slide against the inner peripheral spring guide surfaces 72d and 73d. In this state, the inner circumferential spring guide surfaces 72d and 73d are stationary with respect to the first winding attachment region 77a and the second winding attachment region 77b, respectively.

  Further, during the rotational motion in the state where the rotational speed of the pulley 72 in the direction of the arrow R is equal to or higher than the hub structure 73 as described above, the intermediate region 77c of the coil spring 77 is tightened from the beginning. By being in the state, elastic rotational energy in the direction of loosening is stored in the coil spring 77, and the pulley 72 and the hub structure 73 can instantaneously perform relative elastic rotational motion in opposite directions. Yes. In this embodiment, the space between the intermediate region 77c of the coil spring 77 and the hub structure 73 is secured in the spring accommodating chamber 76, so that the coil spring 77 can be tightened to a smaller diameter. Yes, it can store stronger elastic rotational energy in the direction of loosening.

  Here, when the rotational speed of the crankshaft is changed and the belt speed is suddenly reduced, a force in the direction of arrow T in which the coil spring 77 is wound around the hub structure 73 is applied to the pulley 72 by the belt. As described above, the pulley 72 and the hub structure 73 can be instantaneously and relatively elastically rotated in the opposite directions by the elastic force of the coil spring 77. Therefore, when the belt speed rapidly decreases, the pulley 72 and the hub structure 73 rotate with inertia. When the coil spring 77 is loosened around the hub structure 73 that continues, the pulley 72 can rotate independently in the arrow T direction. Here, from the above-described stationary state, the inner peripheral spring guide surface 72d rotates about 5 degrees (angle) with respect to the first winding attachment region 77a (in the direction of arrow T in FIG. 23). By loosening the winding, the inner diameter of the coil spring 77 increases, and a pressing force is generated by the coil spring 77 against the outer spring guide surface 72e in the direction indicated by the arrow Q in FIG. The same applies to the outer peripheral spring guide surface 73e on the other end side of the coil spring 77. As a result, the coil spring 77 is efficiently wound and loosened without causing a slip between the coil spring 77 and the pulley 72. Similarly, the coil spring 77 is efficiently wound and loosened without causing slippage between the coil spring 77 and the pulley 73 by the pressing force of the coil spring 77 generated on the other end side against the outer spring guide surface 73e. I will. In this state, the inner circumferential spring guide surfaces 72d and 73d are stationary with respect to the first winding attachment region 77a and the second winding attachment region 77b, respectively.

  As a result, belt squealing is suppressed by gently absorbing fluctuations in the rotation of the crankshaft, and belt wear can be prevented. In addition, the influence on the hub structure 3 and the power generation shaft due to the rotation fluctuation of the crankshaft can be reduced.

  As described above, with the pulley structure 71 according to the present embodiment, the first transition region 77t continuous to the first winding region 77a and the first winding region 77a, and the second winding region 77b and the second winding region 77a. In the first transition region 77u that is continuous to the winding region 77b, it is possible to prevent the occurrence of stress concentration due to local contact between the inner circumferential side spring guide surfaces 72d and 73d and the coil spring 77, which is harmful to the coil spring. Wear and breakage can be suppressed. In addition, a state in which both the pulley 72 and the hub structure 73 rotate at the same rotational speed and a state in which the pulley 72 rotates at a rotational speed smaller than the hub structure 73 in the same direction include one end and are linear. The body can be switched using a coil spring 77 having a first attached region extending toward the other end while curving with substantially the same curvature.

  In the present embodiment, the first winding region 77a of the coil spring 77 is between the inner peripheral spring guide surface 72d and the outer peripheral spring guide surface 72e, and the second winding additional region 77b is the inner peripheral spring guide. It is mounted between the surface 73d and the outer peripheral side spring guide surface 73e. By doing so, the coil spring 77 can be reliably and straightly attached to the pulley structure 71 without tilting. That is, if the coil spring 77 is installed with an inclination, an excessive force is likely to be applied to a part of the coil spring 77 due to rotational fluctuation applied to the pulley structure 71, and the coil spring 77 is likely to be damaged. In this respect, in this embodiment, since the mounting direction of the coil spring 77 can be avoided from being inclined, the rotational fluctuation applied to the pulley structure 71 can be uniformly received by the entire spring wire, and the life of the coil spring 77 is extended. be able to.

  For example, in the above embodiment, the winding region of the coil spring 77 is set to about 1 turn, but the number of turns is not limited to this, and it may be 1 turn or more. Furthermore, the number of turns in the transition region is about 1 in the above embodiment, but is not limited to this number.

  In addition, for example, it is preferable that the pulley 72 is actively reduced in weight by, for example, providing a lightening portion. As a result, the rotational inertia moment of the pulley 72 can be reduced, so that the belt tension required to maintain the speed at a certain point of the uneven surface 72a at the belt speed can be relaxed. Therefore, generation of force exceeding the static friction force between the uneven surface 72a and the belt can be suppressed, so that the belt is not worn and the life can be extended.

  Moreover, as a material of the pulley 72, it is preferable to employ a light alloy such as aluminum, for example. Thereby, since the rotational inertia moment of the pulley 72 can be further reduced, there is an effect that the life of the belt can be extended in the same manner as the effect of weight reduction by the above-described thinning.

  Further, the cross-sectional shape of the coil spring 77 may be changed. For example, it is known that the following effects can be obtained by comparing a coil spring having a circular cross section with a rectangular coil spring having a rectangular cross section. That is, with the same relative angular displacement, the same number of turns, and the same spring constant, the maximum tensile (compression) stress generated in the latter coil spring can be reduced to about 70%, while it occurs at the same relative angular displacement. If the maximum tensile (compression) stress is the same and the spring constant is the same, the latter required number of turns is 70%. For the above reason, a square coil spring may be adopted, but the present invention is not limited to this, and the cross-sectional shape of the coil spring may be, for example, a circle.

  Further, in the present embodiment, the case where the pulley structure 71 is provided on the hub structure 73 of the alternator has been described. It is done. Further, the application of the pulley structure of the present invention other than the vehicle equipment is not hindered, and the pulley structure of the present invention can be installed and used in various rotation transmission systems.

(Seventh embodiment)
Next, FIG. 25 is a longitudinal sectional view of the pulley structure 101 according to the seventh embodiment of the present invention. FIG. 26 is an NN cross section in FIG.

  An automobile internal combustion engine (not shown) includes an engine frame (not shown), a crankshaft (not shown), and a generator shaft (not shown) of an alternator. A pulley structure 101 shown in FIG. 25 is installed on the generator shaft of the alternator, and rotates when the power of the engine is transmitted via a crankshaft and a belt (not shown). The pulley structure 101 includes a pulley 102 formed in a cylindrical shape, and an uneven surface 102a capable of transmitting a driving force from the engine by winding the belt on the outer peripheral surface of the pulley 102. Is provided.

  A bearing 104 is disposed on the inner periphery of one end of the pulley 102 in the axial direction, and a bearing 105 is disposed on the inner periphery of the other end in the axial direction. The hub structure 103 is supported by the bearings 104 and 105 so as to be relatively rotatable with respect to the pulley 102, and the hub structure 103 is disposed concentrically with the pulley 102 in the inner space of the pulley 102. . In the present embodiment, dry metal and ball bearings are used as the bearing 104 and the bearing 105, respectively. However, the present invention is not limited to these, and the hub structure 103 is rotatable relative to the pulley 102. As long as it supports,

  A stop member 81 for fixing the bearing 105 so as not to be detached is fitted on the inner periphery of the pulley 102. Moreover, the shaft hole 103a of the hub structure 103 is formed so that the generator shaft (not shown) of the alternator can be fixed.

  A spring accommodating chamber 106 is formed by the pulley 102, the hub structure 103, and the bearings 104 and 105, and a coil spring 107 is accommodated in the spring accommodating chamber 106. The coil spring 107 is an angular spring in which a metallic linear body having a quadrangular cross section is wound spirally.

  In the present embodiment, the housing groove 102b is provided on the inner surface of the pulley 102 facing the spring housing chamber 106, and the outer peripheral surface of the housing groove 102b that faces in the radial direction of the rotation shaft is the first spring guide surface 102d. The coil spring 107 is mounted so that the first contact portion 107a located at the end of the coil spring 107 contacts the first spring guide surface 102d. The first spring guide surface 102d is hard chrome plated. The width of the housing groove 102b in the radial direction of the rotating shaft needs to be large enough to accommodate the linear body constituting the coil spring 107, but the upper limit is not particularly limited here.

  The end of the coil spring 107 is mounted in an elastically deformed state so that the diameter is smaller than the diameter before mounting, and the arrow V in the NN cross section shown in FIG. The pulley inner surface is biased in the direction shown. Further, the linear body tip portion 107c of the coil spring 107 has a corner portion removed, and is formed as a surface in which the surface contacting the pulley inner peripheral surface and the linear body end surface of the coil spring 107 are smoothly continuous with each other. Has been.

  FIG. 28 shows the contact surface side of the PP cross section of the coil spring 107 in FIG. The cross-sectional shape of the contact surface of the coil spring 107 is a linear shape in the central portion indicated by N in the figure, and a crowning process is performed in the portion indicated by O so that the curvature decreases as it approaches the end portion. The corners at the ends are removed.

  On the other hand, a retainer portion 103b is provided on the outer surface of the hub structure 103 facing the spring accommodating chamber 106, and an outer inner peripheral surface of the retainer portion 103b that is oriented in the radial direction of the rotation shaft is defined as a second spring guide surface 103d. The coil spring 107 is mounted so that the second contact portion 107b located at the end of the coil spring 107 on the side of the retainer portion 103b contacts the second spring guide surface 103d.

  The second abutting portion 107b of the coil spring 107 is mounted in a state of being elastically deformed so that the diameter is smaller than the diameter before the mounting, in the same manner as the first abutting portion 107a, and the corner portion is at the tip portion. While being removed, the second contact portion 107b is crowned.

  As described above, the coil spring 7 is disposed substantially concentrically with the pulley structure 101 in the spring accommodating chamber 106, and the pulley 102 and the hub structure 103 are elastically connected via the coil spring 107.

  Next, the operation of the pulley structure 101 will be described.

  As described above, the pulley structure 101 uses the constant frictional force generated on the contact surface between the pulley 102 and the hub structure 103 due to the elastic recovery force of the coil spring 107, and the pulley 102 and the coil spring 107, and A mechanism (spring clutch mechanism) for maintaining the fixed state between the hub structure 103 and the coil spring 107 is provided. When the belt (not shown) is driven by this spring clutch mechanism and the pulley 102 rotates, the rotational motion of the pulley 102 is transmitted to the hub structure 103.

  In this motion, when the rotational torque transmitted from the pulley 102 to the hub structure 103 increases, the coil spring 107 is moved to the pulley 102 or the hub structure 103 when the rotational torque exceeding the frictional force of the spring clutch mechanism is transmitted. As a result, the pulley 102 and the hub structure 103 rotate relative to each other. At this time, the friction acting on the contact surface of the coil spring 107 changes from static friction to dynamic friction, and the frictional force acting between the coil spring 107 and the pulley 102 or between the coil spring 107 and the hub structure 103 decreases. As a result, the rotational torque transmitted between the pulley 102 and the hub structure 103 is reduced.

  Here, the larger the rotational torque transmitted from the pulley 102 to the hub structure 103, the greater the increase in the rotational speed of the hub structure 103 per unit time. Therefore, in a structure that transmits a general rotational torque, a rapid change in speed occurs due to the transmission of a significantly large rotational torque.

  However, in the pulley structure 101 of the present invention, the coil spring 107 can slide on the abutting surfaces of the abutting portions 107a and 107b, and a torque greater than a predetermined amount of rotational torque that can be transmitted by frictional force. Is not transmitted by the slip of the spring clutch mechanism. Therefore, it is possible to suppress rapid fluctuations in the rotation speed of the hub structure 103. In addition, when the rotational torque is transmitted, the coil spring 107 supports the pulley 102 and the hub structure 103 in the entire contact portion between the pulley 102 and the hub structure 103, so that the frictional force acting on the coil spring 107 is It works in a distributed manner on the contact portion of the coil spring 107. Therefore, stress concentration on a part of the coil spring 107 can be suppressed, and fatigue failure of the coil spring 107 can be suppressed. Further, since the rotational torque acting on the coil spring 107 does not become excessively large, it is possible to suppress the deterioration of the coil spring 107.

  The case where the rotational torque transmitted from the pulley 102 to the hub structure 103 increases and the spring clutch mechanism can slip is, for example, when the spring clutch mechanism is fixed without slipping (gripping state). There are cases where the amount of increase in the rotational speed per unit time is large, that is, the rotational speed of the pulley 102 increases rapidly. At this time, if the rotational torque that would be transmitted to the hub structure 103 is greater than the predetermined rotational torque that can be transmitted by the frictional force of the spring clutch mechanism, the spring clutch mechanism Changes from a gripping state to a sliding state. Therefore, the rotation of the hub structure 103 follows the rotation of the pulley 102 and the rotation speed does not increase rapidly.

  Similarly, even when the amount of decrease in the rotational speed of the pulley 102 per unit time is large, that is, when the rotational speed of the pulley 102 rapidly decreases, it is possible to cause the spring clutch mechanism to slip. In this case, the rotational torque acts in a direction to stop the rotation of the hub structure 103 that continues to rotate at the same rotational speed due to the inertial force. If the rotational torque is greater than or equal to a predetermined rotational torque that can be transmitted by the frictional force of the spring clutch mechanism, the spring clutch mechanism changes from a gripping state to a sliding state. Therefore, it is possible to suppress a rapid decrease in the rotational speed of the hub structure 103.

  Thus, when the contact portion of the coil spring 107 slides on the pulley 102 or the guide surfaces 102d and 103d of the hub structure 103, the guide surfaces 102d and 103d may be worn. If the friction coefficient of the contact at the part changes due to wear, the predetermined rotational torque at which the slip occurs changes, which causes a problem that the occurrence of slip becomes unstable. In this embodiment, since the hard chrome plating is applied to the pulley 102 and the hub structure 103 with which the coil spring abuts, the wear can be suppressed. Note that the surface hardening treatment of the contact portion between the pulley 102 and the hub structure 103 is not limited to hard chrome plating, but can be performed by nickel plating, induction hardening, ceramic spraying, or the like.

  Further, the coil spring 107 is a square spring, and the contact state can be stably maintained depending on the width of the contact surface. Here, since the sharp corner portion of the linear body tip portion 107c of the coil spring 107 is removed, it is possible to prevent the surface of the pulley 102 from being damaged. Further, by adopting such a shape, the coil spring 107 can be easily inserted into the pulley 102 when the pulley structure 101 is assembled. Further, the coil spring 107 is crowned (see FIG. 28) and the corners of the cross section are smoothed, so that the surface of the pulley 102 can be prevented from being damaged.

  In addition, as shown in FIG. 27 as a modification of the coil spring, a gap δ is provided between the tip and the pulley 102 by bending the vicinity of the tip of the coil spring 108 inward in the radial direction so that the coil diameter becomes small. It is also possible to prevent the surface of the pulley 102 from being damaged.

  Further, the coil spring 107 is not limited to the one having the cross-sectional shape shown in FIG. 28, but has a cross-sectional shape in which the entire contact surface is curved, for example, the curvature decreases from the central portion to the corner portion as shown in FIG. It is possible to prevent the pulley 102 from being damaged and maintain a stable contact state by using the coil spring 109 having a cross-sectional shape that has been crowned so that (R1> R2> R3> R4).

  Also, the greater the elastic recovery force that the coil spring 107 biases the pulley 102 and the hub structure 103, the greater the predetermined rotational torque that causes slipping. Therefore, the coil diameter of the coil spring used and the elastic coefficient of the material are adjusted. By doing so, it is possible to adjust the predetermined rotational torque. The coil diameter need not be uniform in the axial direction, and the elastic recovery force may be adjusted by partially increasing only the coil diameter of the contact portions 107a and 107b with the pulley 102 or the hub structure 103. Is possible.

  Further, the insertion width l (see FIG. 25) of the pulley structure 101 is designed to be about 0.2 mm to 5 mm smaller than the axial length of the coil spring, so that both ends of the coil spring attached to the pulley structure 101 are designed. Is in contact with the receiving groove 102b and the retainer portion 103b in the axial direction and is compressed in the axial direction, so that generation of abnormal noise due to end play can be suppressed.

(Eighth embodiment)
Next, FIG. 30 is a longitudinal sectional view of the pulley structure 121 according to the eighth embodiment of the present invention. FIG. 31 is a diagram showing the shape of the second spring guide surface 123d of the hub structure shown in FIG. In the pulley structure 121 according to the eighth embodiment, the coil spring 127 biases the pulley 122 and the hub structure 123 radially inward to form a spring clutch mechanism, and the coil in the hub structure 123 The second spring guide surface 123d, which is a contact surface with the spring 127, is different from the seventh embodiment in that it is formed as a surface provided with the inclined grooves 51 at regular intervals (see FIG. 31). In addition, the same code | symbol is attached | subjected to the same member and description is abbreviate | omitted. Also, the pulley 122 rotates by driving a belt (not shown) wound around the concave and convex surface 122a as in the seventh embodiment.

  In the present embodiment, the housing groove 122b is provided on the inner surface of the pulley 122 facing the spring housing chamber 126, and the inner outer peripheral surface of the housing groove 122b that faces in the radial direction of the rotation shaft is defined as the first spring guide surface 122d. The coil spring 127 is mounted so that the first contact portion 127a located at the end of the coil spring 127 contacts the first spring guide surface 122d.

  The end of the coil spring 127 is mounted in a state of being elastically deformed so that the diameter is larger than the diameter before the mounting, and the guide surface 122d of the pulley 122 is reduced in the direction of decreasing the diameter by the elastic recovery of the coil spring 127. Is energized.

  On the other hand, the inner peripheral surface of the retainer portion 123b that faces in the radial direction of the rotating shaft is the second spring guide surface 123d, and the second contact portion 127b that is located at the end of the coil spring 127 on the retainer portion 123b side is the second. A coil spring 107 is mounted so as to abut on the spring guide surface 123d.

  The second contact portion 127b is mounted in a state of being elastically deformed so that the diameter becomes larger than the diameter before the mounting, in the same manner as the first contact portion 127a.

  The pulley structure 121 configured as described above is a state in which the hub structure 123 can be rotated relative to the pulley 122 due to slippage by a spring clutch mechanism by elastic recovery in a direction of reducing the diameter of the coil spring 127. Thus, the rotational movement of the pulley 122 is transmitted to the hub structure 123.

  Similar to the seventh embodiment, the magnitude of the predetermined rotational torque at which the spring clutch mechanism slips increases as the friction coefficient between the coil spring 127 and the pulley 122 or between the coil spring 127 and the hub structure 123 increases. Become. In the present embodiment, by forming the inclined grooves 51 (see FIG. 31) at regular intervals in the rotational direction on the guide surface 123d of the hub structure 123, the friction coefficient is reduced, and the coil spring 127 is slipped. The lubricity is improved.

  By processing the contact surface in this way, it is possible to reduce the magnitude of the predetermined rotational torque that causes the slip, and to reduce the influence of the hub structure 123 due to the rotational speed fluctuation of the pulley 122. it can. In addition to the shape shown in FIG. 31, as shown in FIG. 32, a process for forming an emboss 52 on the contact surface is performed, or as shown in FIG. 33, a material 53 with good lubricity such as dry metal is used. The friction coefficient can be reduced by press-fitting. In addition, the guide surface 122d of the pulley 122 can be processed without being limited to the case of processing the hub structure 123.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. Furthermore, in this embodiment, although the effect by the structure of this invention is described, these effect is an example and does not limit this invention.

1, 11, 21, 61, 71, 101, 111, 121 Pulley structure 2 First rotating body 2b, 12b, 22b First receiving groove 3 Second rotating body 3b, 13b, 23b Second receiving groove 4, 5 Bearing 6, 106, 126 Spring accommodating chamber 7, 67, 77 Coil spring 12, 22, 62, 72, 102, 122 Pulley (first rotating body)
12c, 22c, 62c Spring stopper surface 12d, 22d, 13d, 23d, 113d Spring guide surface 13, 23, 63, 73, 103, 113, 123 Hub structure (second rotating body)
13c, 23c Spring stopper surface 24, 25 Bearing 16, 26a, 16b, 66, 76 Spring accommodating chamber 17, 27, 117 Coil spring 17a, 27a, 67a, 77a, 117a First attached region 17b, 67b, 77b, 117b Second winding attached region 27b Other end 62d, 63d, 72d, 73d Inner peripheral spring guide surface 62f, 72f First spiral path 63f, 73f Second spiral path 67t, 77t First transition area 67u, 77u Second transition area 72e, 73e Outer peripheral side spring guide surfaces 67c, 77c, 117c Intermediate regions 102b, 122b Housing grooves 102d, 122d First spring guide surfaces 103b, 123b Retainer portions 103d, 123d Second spring guide surfaces 107, 108, 109, 127 Angular springs (Coils Ring)
107a, 127a First contact portion 107b, 127b Second contact portion 117t Transition region

Claims (8)

A first rotating body that allows the belt to be wound;
A second rotating body that is rotatable relative to the first rotating body inside the first rotating body;
A spring accommodating chamber formed between the first rotating body and the second rotating body;
A coil spring housed in the spring housing chamber and having one end abutting on the first rotating body and the other end abutting on the second rotating body,
Both ends of the coil spring are arranged in an elastically deformed state so that the diameter changes, and the diameter of the coil spring is elastically recovered by the first rotating body and the second rotating body. In contact with the first rotating body and the second rotating body in a suppressed state,
Even if the portion other than the end portion of the coil spring is deformed in the direction in which the diameter changes during relative rotation of the first rotating body and the second rotating body, the first rotating body and the second rotating body. Without touching any of the rotating bodies,
When a rotational torque of a predetermined magnitude or more is transmitted between the first rotating body and the second rotating body via the coil spring, the coil spring makes contact with the first rotating body. At least one of the first contact part that is a part and the second contact part that is a contact part with the second rotating body is in contact with the first rotating body or the second rotating body A pulley structure characterized by sliding in a state.   When the amount of increase in rotational speed per unit time of the first rotating body is greater than or equal to a predetermined magnitude, the first contact portion that is the contact portion with the first rotating body in the coil spring and the first The at least any one of the 2nd contact part which is a contact part with 2 rotation bodies slides in the state contact | abutted with respect to the said 1st rotation body or the said 2nd rotation body, It is characterized by the above-mentioned. 2. The pulley structure according to 1.   When the amount of decrease in the rotational speed per unit time of the first rotating body is greater than or equal to a predetermined magnitude, the first contacting portion and the second contacting portion that are the contacting portions of the coil spring with the first rotating body. The at least one of the second contact portions that are contact portions with the rotating body slides in a state of being in contact with the first rotating body or the second rotating body. The pulley structure described in 1.   The surface hardening process is performed on at least one of the contact surfaces of the first rotating body and the second rotating body with which the coil spring is in contact. The pulley structure according to any one of claims.   At least one of the contact surfaces of the first rotating body and the second rotating body with which the coil spring comes into contact is a first contact portion that is a contact portion with the first rotating body in the coil spring, or The machined so as to have a surface state in which a friction coefficient generated between the second rotating body and the second abutting portion which is a contacting portion with the second rotating body is reduced. The pulley structure according to any one of 4.   The coil spring is an angular spring in which the material cross section of the coil spring is a square shape, and a surface of the angular spring that contacts the first rotating body or the second rotating body, and a material end surface of the angular spring, The pulley structure according to any one of claims 1 to 5, wherein the pulley structures are formed as surfaces that are smoothly continuous with each other.   The coil spring is an angular spring in which the material cross section of the coil spring is a quadrangle, and the material end of the angular spring is arranged with respect to the first rotating body and the second rotating body via a gap. The pulley structure according to any one of claims 1 to 6, wherein the pulley structure is provided. The coil spring is an angular spring in which the material cross-section of the coil spring is a quadrangular shape, and the surface of the angular spring that contacts the first rotating body or the second rotating body is crowned. The pulley structure according to any one of claims 1 to 7, wherein:

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