TWI882009B - Pulleys and centrifugal clutches - Google Patents

Abstract

[Topic] The present invention provides a pulley device that allows a cam mechanism that displaces a movable side driven plate as a movable sheave to operate smoothly, and a centrifugal clutch having the pulley device. [Solution] The pulley device 130 has a sliding sleeve 153 between a fixed side driven plate 140 and a movable side driven plate 150 that are rotationally driven by the driving force of the engine. In the fixed side driven plate 140, a groove-shaped concave cam portion 144 is formed on a fixed side sleeve 142 formed in a cylindrical shape. In the movable side driven plate 150, the sliding sleeve 153 is fitted into the movable side sleeve 152 formed in a cylindrical shape. The sliding sleeve 153 is formed in a cylindrical shape and is fitted with the outer peripheral portion of the fixed side sleeve 142 and the inner peripheral portion of the movable side sleeve 152. In addition, the sliding sleeve 153 is formed with a convex cam portion 154 which is slidably fitted with the concave cam portion 144.

Description

Pulleys and centrifugal clutches

The present invention relates to a pulley device for transmitting driving force from a driving source such as an engine and a centrifugal clutch having the pulley device.

In the past, there have been pulley devices that transmit driving force from a driving source such as an engine. For example, the following patent document 1 discloses a centrifugal clutch having a pulley device composed of a pair of fixed sheaves and a movable sheave, and the pulley device receives the driving force from the engine through a belt. In this case, the movable sheave is constructed in the following manner: a cylindrical movable wheel hub is engaged with a cylindrical fixed wheel hub formed on the fixed sheave through a cylindrical sliding member, thereby approaching or separating from the fixed sheave. Then, the movable sheave obtains axial thrust by engaging a spiral cam portion formed on the front end of the movable wheel hub with a spiral cam support member provided on a drive plate that is rotationally driven integrally with the fixed sheave. [Knowledge and technology literature] [Patent literature]

[Patent Document 1] Japanese Patent Application Publication No. 2019-127993

However, in the pulley device described in the above-mentioned patent document 1, the movable sheave slides back and forth on the fixed wheel hub through the sliding member. Therefore, when a deviation occurs between the axial direction of the sliding member and the axial direction of the movable wheel hub, there will be a problem that useless friction resistance is generated between the cam portion formed on the movable sheave and the cam support member provided on the drive plate, thereby hindering smooth displacement.

The present invention is made to address the above-mentioned problem, and its purpose is to provide a pulley device that can smoothly operate a cam mechanism that displaces a movable side driven plate as a movable sheave, and a centrifugal clutch having the pulley device.

In order to achieve the above-mentioned purpose, the present invention is characterized in that it has: a fixed side driven plate, which has a fixed side plate protruding outwardly in a flange shape on the outer peripheral surface of a cylindrical fixed side sleeve, and receives a driving force from a driving source through a belt to rotate and drive; a movable side driven plate, which has a movable side plate protruding outwardly in a flange shape on the outer peripheral surface of a cylindrical movable side sleeve and clamps the belt together with the fixed side plate, and one side is close to the fixed side plate. Or separately, one side receives the driving force from the driving source through the belt and is rotationally driven; the sliding sleeve is formed into a cylindrical shape between the fixed side sleeve and the movable side sleeve and is displaced integrally with the movable side sleeve and slides relatively to the fixed side sleeve; the concave cam portion is formed along the axial spiral cut in one of the sliding sleeve and the fixed side sleeve; and the convex cam portion is slidably engaged in the concave cam portion in the other of the sliding sleeve and the fixed side sleeve.

According to the characteristics of the present invention constructed in this way, the pulley device is formed with a concave cam portion or a convex cam portion that engages with the convex cam portion or the concave cam portion formed on the fixed side sleeve on the cylindrical sliding sleeve that is displaced integrally with the movable side sleeve relative to the fixed side sleeve, and the sliding sleeve is directly slidably displaced relative to the fixed side sleeve. Thus, according to the pulley device of the present invention, the cam mechanism composed of the convex cam portion and the concave cam portion can operate smoothly. In addition, according to the pulley device of the present invention, the concave cam portion or the convex cam portion is formed on the sliding sleeve, thereby reducing the number of parts and realizing the miniaturization and lightness of the pulley device and reducing the manufacturing burden.

Furthermore, another feature of the present invention is that, in the aforementioned pulley device, the concave cam portion or the convex cam portion formed on the sliding sleeve is formed by extending in the axial direction at one end portion of the sliding sleeve formed in a cylindrical shape.

According to another feature of the present invention constructed in this way, in the pulley device, the concave cam portion or the convex cam portion formed on the sliding sleeve is formed by extending in the axial direction at one end portion of the sliding sleeve formed in a cylindrical shape, so that the sliding sleeve itself will not be enlarged in the radial direction and can be constructed in a small size.

Furthermore, another feature of the present invention is that, in the aforementioned pulley device, the concave cam portion or the convex cam portion formed on the sliding sleeve is non-contacting with respect to the fixed-side sleeve.

According to another feature of the present invention constructed in this way, in the pulley device, the concave cam portion or the convex cam portion formed on the sliding sleeve is configured to be non-contact with respect to the fixed side sleeve, thereby reducing the friction resistance of the sliding sleeve when sliding and allowing it to slide smoothly.

Furthermore, another feature of the present invention is that, in the aforementioned pulley device, the movable side sleeve is formed with a cam connection portion, which is formed in a concave or convex shape; and the sliding sleeve is formed with a convex or concave sleeve connection portion that is engaged with the cam connection portion.

According to another feature of the present invention constructed in this manner, in the pulley device, the sliding sleeve and the movable side sleeve are connected by fitting together a sleeve connecting portion formed in a convex or concave shape on the sliding sleeve and a cam connecting portion formed in a concave or convex shape on the movable side sleeve, thereby being able to integrate the sliding sleeve and the movable side sleeve with a simple structure.

Furthermore, another feature of the present invention is that, in the aforementioned pulley device, the sliding sleeve and the fixed side sleeve are made of different materials.

According to another feature of the present invention constructed in this way, in the pulley device, the sliding sleeve and the fixed side sleeve are made of different materials, so that the sliding properties of both can be improved and the wear degradation can be suppressed. In this case, in the pulley device, the sliding sleeve can be made of a resin material and the fixed side sleeve can be made of a metal material.

Furthermore, in order to achieve the above-mentioned purpose, the present invention is characterized in that it comprises: a fixed side driven plate, which has a fixed side plate protruding outwardly in a flange shape on the outer peripheral surface of a fixed side sleeve formed in a cylindrical shape, and receives a driving force from a driving source through a belt to be rotationally driven; a movable side driven plate, which has a movable side plate protruding outwardly in a flange shape on the outer peripheral surface of a movable side sleeve formed in a cylindrical shape and clamps the belt together with the fixed side plate, and is close to or separated from the fixed side plate. One side receives the driving force from the driving source through the belt and is rotationally driven; the sliding sleeve is formed into a cylindrical shape and arranged between the fixed side sleeve and the movable side sleeve, and is arranged to be unable to be relatively displaced relative to the fixed side sleeve, and slides relatively to the movable side sleeve; the concave cam portion is formed by an axial spiral cut on one of the sliding sleeve and the movable side sleeve; and the convex cam portion is slidably engaged in the concave cam portion on the other of the sliding sleeve and the movable side sleeve.

According to the characteristics of the present invention constructed in this way, the pulley device is formed with a concave cam portion or a convex cam portion that engages with the convex cam portion or the concave cam portion formed on the movable side sleeve on the cylindrical sliding sleeve that is set to be unable to rotate relative to the fixed side sleeve, and the movable side sleeve directly slides and displaces on the sliding sleeve. Thereby, according to the pulley device of the present invention, the cam mechanism composed of the convex cam portion and the concave cam portion can operate smoothly. In addition, according to the pulley device of the present invention, the concave cam portion or the convex cam portion is formed on the sliding sleeve, thereby reducing the number of parts and realizing the miniaturization and lightness of the pulley device and reducing the manufacturing burden.

Furthermore, another feature of the present invention is that, in the aforementioned pulley device, the sliding sleeve has a cylindrical main body portion disposed between the fixed side sleeve and the movable side sleeve; and the concave cam portion or the convex cam portion is formed on the outer side of the main body portion in the sliding sleeve.

According to another feature of the present invention constructed in this way, the pulley device is formed with a concave cam portion or a convex cam portion on the outer side of the main body in the sliding sleeve, so that the convex cam portion or the concave cam portion formed on the movable side sleeve sliding on the main body can be cam-engaged smoothly.

Furthermore, another feature of the present invention is that, in the aforementioned pulley device, the sliding sleeve has an outer cylindrical portion in a state of covering the concave cam portion or the convex cam portion formed on the outer side of the main body portion.

According to another feature of the present invention constructed in this way, the pulley device has an outer cylindrical portion in a state of covering the concave cam portion or the convex cam portion on the outer side of the main body portion formed in the sliding sleeve, thereby preventing foreign matter from entering the cam engagement portion and maintaining smooth cam engagement for a long time.

Furthermore, another feature of the present invention is that, in the aforementioned pulley device, the sliding sleeve and the movable side sleeve are made of different materials.

According to another feature of the present invention constructed in this way, in the pulley device, the sliding sleeve and the movable side sleeve are made of different materials, so that the sliding properties of both can be improved and the wear degradation can be suppressed. In this case, in the pulley device, the sliding sleeve can be made of a resin material and the movable side sleeve can be made of a metal material.

Furthermore, the present invention can be implemented not only as an invention of a pulley device, but also as an invention of a centrifugal clutch having the pulley device.

Specifically, the centrifugal clutch may include: a pulley device as in any one of claims 1 to 5; a driving plate connected to a fixed-side sleeve and rotationally driven integrally with a fixed-side driven plate; a clutch housing having a cylindrical surface concentrically arranged with the driving plate on the outer side of the driving plate and connected to a driving shaft; and a clutch counterweight extending along the circumferential direction of the driving plate and having a clutch shoe facing the cylindrical surface of the clutch housing, one end side of the circumferential direction of the clutch shoe being rotatably mounted on the driving plate, and the other end side being displaced toward the cylindrical surface side of the clutch housing. Accordingly, the centrifugal clutch can be expected to have the same function and effect as the above-mentioned pulley device.

Furthermore, the centrifugal clutch may include: a pulley device as in any one of the seventh to eleventh forms; a driving plate connected to a fixed side sleeve and rotationally driven integrally with a fixed side driven plate; a clutch housing having a cylindrical surface arranged concentrically with the driving plate on the outer side of the driving plate and connected to a driving shaft; and a clutch counterweight extending and formed along the circumferential direction of the driving plate, having a clutch shoe facing the cylindrical surface of the clutch housing, one end side in the aforementioned circumferential direction being rotatably mounted on the driving plate, and the other end side being displaced toward the cylindrical surface side of the clutch housing. Accordingly, it can be expected that the centrifugal clutch has the same function and effect as the above-mentioned pulley device.

Another feature of the present invention is that, in the centrifugal clutch, the sliding sleeve can be arranged on the driving plate. According to another feature of the present invention constructed in this way, in the centrifugal clutch, the sliding sleeve is arranged on the driving plate, so that the structure of the fixed side driven plate can be simplified and lightened.

<First embodiment> The following describes an embodiment of the pulley device of the present invention and a centrifugal clutch having the pulley device with reference to the drawings. FIG. 1 is a top view schematically showing the structure of a power transmission mechanism 100 having a pulley device 130 and a centrifugal clutch 200 of the first embodiment of the present invention. In this case, in FIG. 1, the upper half of each of the pulley device 130 and the centrifugal clutch 200 shows a state where the movable side driven plate 150 is closest to the fixed side driven plate 140, and the lower half of each of the pulley device 130 and the centrifugal clutch 200 shows a state where the movable side driven plate 150 is most separated from the fixed side driven plate 140.

The power transmission mechanism 100 having the pulley device 130 and the centrifugal clutch 200 is mainly a mechanical device in a two-wheeled motor vehicle such as a scooter, and is disposed between the engine and the rear wheel as a driving wheel, and automatically changes the speed reduction ratio relative to the engine speed, and transmits the rotational driving force to the rear wheel or blocks it. In this case, the centrifugal clutch 200 is a mechanical device that blocks the rotational driving force from being transmitted to the driven side before the engine reaches a predetermined speed, and transmits the rotational driving force to the driven side when the engine reaches a predetermined speed.

(Construction of pulley device 130 and centrifugal clutch 200) The power transmission mechanism 100 mainly includes a transmission 101 and a centrifugal clutch 200. The transmission 101 is a mechanical device that reduces the speed of the rotational driving force from the engine (not shown) in a stepless manner and transmits it to the centrifugal clutch 200. It mainly includes a drive pulley 110, a V-belt 120 and a pulley device 130. Among them, the drive pulley 110 is a mechanical device that is provided on a crankshaft 111 extending from the engine and is directly driven by the rotational driving force of the engine. It mainly includes a fixed drive plate 112 and a movable drive plate 113.

The fixed drive plate 112 is a component that is driven to rotate while clamping and holding the V-belt 120 together with the movable drive plate 113. It is formed by forming a metal material into a conical cylinder. The fixed drive plate 112 is fixedly mounted on the crankshaft 111 with the convex side facing the movable drive plate 113 side (engine side). That is, the fixed drive plate 112 is driven to rotate integrally with the crankshaft 111 at any time. In addition, on the concave side surface of the fixed drive plate 112, a plurality of heat sinks 112a are arranged radially with the axis of the crankshaft 111 as the center.

The movable drive plate 113 is a component that is driven to rotate while clamping and holding the V-belt 120 together with the fixed drive plate 112. The movable drive plate 113 is formed into a conical tube shape. The movable drive plate 113 is mounted on the crankshaft 111 with the convex side of the plate facing the fixed drive plate 112. In this case, the movable drive plate 113 is mounted on the sleeve bearing 114 fixedly engaged with the crankshaft 111 through the impregnated bushing, and is mounted to slide freely in the axial direction and the circumferential direction relative to the sleeve bearing 114.

On the other hand, on the concave side of the movable drive plate 113, a plurality of roller weights 115 are provided in a state of being pushed by the ramp plate 116. The roller weight 115 is a component formed by forming a metal material into a cylindrical shape, and is used to move radially outward according to the increase in the number of rotations of the movable drive plate 113, thereby cooperating with the ramp plate 116 to push the movable drive plate 113 toward the fixed drive plate 112. In addition, the ramp plate 116 is a component that pushes the roller weight 115 toward the movable drive plate 113, and is formed by bending a metal plate toward the movable drive plate 113.

The V-belt 120 is a component for transmitting the rotational driving force of the driving pulley 110 to the driven pulley 131 of the pulley device 130, and is a core wire formed into an endless loop covered with an elastic material such as a rubber material. The V-belt 120 is arranged between the fixed driving plate 112 and the movable driving plate 113, and between the fixed side driven plate 140 and the movable side driven plate 150 of the driven pulley 131, and is installed between the driving pulley 110 and the driven pulley 131.

The pulley device 130 is a mechanical device that is rotationally driven by the rotational driving force from the engine transmitted through the driving pulley 110 and the V-belt 120, and is composed of a driven pulley 131. As shown in FIG. 2, the driven pulley 131 is composed of a fixed side driven plate 140 and a movable side driven plate 150.

The fixed side driven plate 140 is a component that is rotated and driven while clamping and holding the V-belt 120 together with the movable side driven plate 150, and is formed by forming a metal material such as aluminum into a conical cylinder. The fixed side driven plate 140 is mainly composed of a fixed side plate 141 and a fixed side sleeve 142.

The fixed side plate 141 is a portion that sandwiches the V-belt 120 together with the movable side plate 151, and is formed in a conical shape that protrudes convexly toward the movable side plate 151. A fixed side sleeve 142 is formed at the center of the fixed side plate 141.

The fixed side sleeve 142 is a portion that is integrally driven to rotate with the fixed side plate 141, and is formed into a cylindrical shape extending in a direction perpendicular to the fixed side plate 141. The fixed side plate 141 is connected to the end of one side (the right side in the figure) of the fixed side sleeve 142, and a cam-forming protrusion 143 is formed in a portion adjacent to the connecting portion. In addition, an external tooth-shaped bolt groove is formed at the end of the other side (the left side in the figure) of the fixed side sleeve 142, and is connected to the drive plate 210 through the bolt groove by bolt groove engagement.

The cam forming protrusion 143 is a portion for forming a concave cam portion 144 on the fixed side sleeve 142, and is formed by protruding from the outer surface of the fixed side sleeve 142 in a convex shape. Here, the concave cam portion 144 is a portion that is engaged with the convex cam portion 154 in a state of free sliding. In this embodiment, the cam forming protrusion 143 is formed in a spiral shape that is twisted in the circumferential direction of the fixed side sleeve 142 and extends in the axial direction. In this case, three cam forming protrusions 143 are formed at equal intervals in the circumferential direction of the fixed side sleeve 142.

Thus, a concave cam portion 144 is formed between two adjacent cam-forming protrusions 143 on the outer periphery of the fixed side sleeve 142. Therefore, three concave cam portions 144 are formed on the outer periphery of the fixed side sleeve 142 in the circumferential direction with the cam-forming protrusions 143 interposed therebetween. In this case, the three concave cam portions 144 are respectively formed into grooves extending in a spiral shape in the axial direction of the fixed side sleeve 142. Furthermore, the three concave cam portions 144 are formed by the bottoms protruding from the outer surface of the fixed side sleeve 142. That is, the outer diameter of the portion of the fixed side sleeve 142 where the cam-forming protrusions 143 are formed is formed slightly thicker to improve rigidity.

In the fixed side driven plate 140, the fixed side sleeve 142 including the cam forming protrusion 143 and the concave cam portion 144 and the fixed side plate 141 are formed into one body by integrally forming with the same material. In addition, in the fixed side driven plate 140, the fixed side sleeve 142 including the cam forming protrusion 143 and the concave cam portion 144 and the fixed side plate 141 can also be formed by different parts and connected to each other by welding, etc., so as to form one body. In addition, in the fixed side driven plate 140, the cam forming protrusion 143 can also be formed with another component relative to the fixed side sleeve 142 and connected, so as to be formed on the fixed side sleeve 142.

In the fixed side driven plate 140, a drive shaft 145 passes through the fixed side sleeve 142. The drive shaft 145 is a metal rotating shaft, which is used to drive the rear wheel of the two-wheeled motor vehicle equipped with the power transmission mechanism 100 through a transmission device not shown in the figure. In this case, the rear wheel of the two-wheeled motor vehicle is installed at the end (not shown in the figure) of one side (right side in the figure) of the drive shaft 145. The drive shaft 145 supports the fixed side driven plate 140 through bearings 146a and 146b. In addition, an external thread is formed at the front end portion on the left side of the driving shaft 145, and the clutch housing 230 is installed through the external thread and the nut screwed on the external thread. In addition, in FIG. 1, the driving shaft 145 is represented by a two-point chain.

The bearings 146a and 146b are annular parts for supporting the fixed side driven plate 140 on the drive shaft 145 in a state where the fixed side driven plate 140 can be rotatably driven. In this case, the bearing 146a is provided at the frontmost end (the left end in the figure) where the drive shaft 145 supports the fixed side sleeve 142. Moreover, the bearing 146b is provided at the rearmost end (the right end in the figure) where the drive shaft 145 supports the fixed side sleeve 142. That is, the bearing 146b is provided at a position that overlaps radially inwardly with the cam forming protrusion 143 and the concave cam portion 144. In addition, the bearing 146b can also be configured with the same load-bearing capacity as the bearing 146a, but in the present embodiment, its axial length is formed to be longer than the bearing 146a to configure a larger load-bearing capacity.

The movable side driven plate 150 is a component that is driven to rotate while sandwiching and holding the V-belt 120 together with the fixed side driven plate 140, and is formed by forming a metal material such as aluminum into a conical tube shape. The movable side driven plate 150 is mainly composed of a movable side plate 151 and a movable side sleeve 152.

The movable side plate 151 is a portion that sandwiches the V-belt 120 together with the fixed side plate 141, and is formed in a conical shape that protrudes convexly toward the fixed side plate 141. A movable side sleeve 152 is formed at the center of the movable side plate 151.

The movable side sleeve 152 is a portion that is integrally driven to rotate with the movable side plate 151, and is formed into a cylindrical shape extending in a direction perpendicular to the movable side plate 151. In this case, the movable side sleeve 152 is formed into an inner diameter that can be passed through the fixed side sleeve 142. The movable side plate 151 is connected to the end of one side (the right side in the figure), and the cam connecting portion 152a is connected to the end of the other side (the left side in the figure).

The cam connection part 152a is a part for connecting the sliding sleeve 153, and is formed by cutting a part of the end of the movable side sleeve 152 concavely in the axial direction. In this embodiment, the cam connection part 152a is formed by forming three concave notches at the end of the movable side sleeve 152 in an evenly arranged manner along the circumferential direction.

As shown in FIG. 2 , the sliding sleeve 153 is disposed between the fixed side sleeve 142 and the movable side sleeve 152 so that the movable side sleeve 152 slides relative to the fixed side sleeve 142 and is used to form a convex cam portion 154 that engages with the concave cam portion 144. The sliding sleeve 153 is formed by forming a resin material into a cylindrical shape. The cylindrical body constituting the sliding sleeve 153 is formed to have an outer diameter that can be slidably fitted on the inner peripheral surface of the movable side sleeve 152, and is formed to have an inner diameter that can be slidably fitted on the outer peripheral surface of the fixed side sleeve 142. In addition, in the sliding sleeve 153, a sleeve connecting portion 153a is formed at one end of the cylindrical body, and a convex cam portion 154 is formed at the other end.

The sleeve connecting portion 153a is a portion that is engaged with the cam connecting portion 152a, and is formed by protruding radially outward from one end of the sliding sleeve 153. In this case, the sleeve connecting portion 153a is formed with three protrusions evenly arranged along the circumferential direction on the end of the sliding sleeve 153 in such a manner that the sleeve connecting portion 153a is respectively engaged with the three cam connecting portions 152a.

The convex cam portion 154 protrudes from the inner circumferential surface of the movable side sleeve 152 and is slidably engaged with the aforementioned concave cam portion 144 formed on the fixed side sleeve 142. It is formed to protrude in a spiral shape in the axial direction at the end of the sliding sleeve 153. In this case, the convex cam portion 154 may also be configured to contact the outer circumferential surface of the fixed side sleeve 142, but in this embodiment, it is extended in a non-contact state. Three convex cam portions 154 are formed at equal intervals in the circumferential direction at the end of the sliding sleeve 153 in a manner corresponding to the concave cam portion 144.

That is, between the three convex cam portions 154, the cam forming notches 153b for forming the convex cam portions 154 are respectively extended in a spiral shape. Then, the three cam forming notches 153b are slidably engaged with the cam forming protrusions 143 formed on the fixed side sleeve 142. Therefore, the cam forming protrusions 143 formed on the fixed side sleeve 142 can be regarded as the convex cam portion of the present invention formed on the fixed side sleeve 142, and the cam forming notches 153b formed on the sliding sleeve 153 (movable side sleeve 152) can also be regarded as the concave cam portion of the present invention formed on the sliding sleeve 153 (movable side sleeve 152).

The sliding sleeve 153 is fixedly fitted in the movable side sleeve 152 of the movable side driven plate 150 through an adhesive or the like in a state where the sleeve connecting portion 153a is fitted in the cam connecting portion 152a. Thereby, the sliding sleeve 153 is rotationally driven integrally with the movable side sleeve 152 in a state where the convex cam portion 154 is fitted in the concave cam portion 144 formed in the fixed side sleeve 142.

In addition, as the resin material constituting the sliding sleeve 153, a thermoplastic resin or a thermosetting resin having heat resistance and wear resistance can be used, preferably an engineering plastic or a super engineering plastic. Specifically, as the thermoplastic resin, polyetheretherketone resin (PEEK), polyphenylene sulfide resin (PPS), polyamideimide resin (PAI), fluororesin (PTFE) or polyimide resin (PI) can be used, and as the thermosetting resin, diallyl phthalate resin (PDAP), epoxy resin (EP) or silicone resin (SI) can be used.

On the other hand, a torsion spring 155 is provided on the concave surface of the movable side driven plate 150 between the drive plate 210 in the centrifugal clutch 200. The torsion spring 155 is a coil spring for elastically pressing the movable side driven plate 150 toward the fixed side driven plate 140. That is, the transmission 101 changes the engine speed in a stepless manner by the relationship between the diameter of the V-belt 120 sandwiched by the interval between the fixed drive plate 112 and the movable drive plate 113 and the diameter of the V-belt 120 sandwiched by the interval between the fixed side driven plate 140 and the movable side driven plate 150. Then, a centrifugal clutch 200 is provided on each front end side of the fixed side sleeve 142 and the driving shaft 145 .

The centrifugal clutch 200 is a mechanical device that transmits the rotational driving force of the engine transmitted through the transmission 101 to the drive shaft 145 or blocks it. It mainly includes a drive plate 210, three clutch weights 220 and a clutch housing 230.

The drive plate 210 is a component that is integrally driven and rotated with the fixed side sleeve 142, and is formed by forming a metal material into a stepped circular plate shape. More specifically, the drive plate 210 is formed in the following manner: an inner tooth-shaped bolt groove is formed in the central portion of the flat bottom 211, and is engaged with the outer tooth-shaped bolt groove of the fixed side sleeve 142 while being penetrated, and a flange portion 212 is formed that further protrudes radially outward in a flange shape through a stepped portion that stands up around the bottom 211.

In the driving plate 210, the torsion spring 155 is provided inside the step portion in the outer edge portion of the bottom 211. In addition, three swing support pins 213 and a counterweight push body support portion 215 are provided on the flange portion 212 at equal intervals along the circumferential direction.

The swing support pin 213 is a part used to support one end side of the clutch counterweight 220 described below so that it can rotate and to swing the other end side. It is composed of a stepped rod body made of metal. In this case, the swing support pin 213 is fixedly mounted on the flange portion 212 by a mounting bolt 213a. The swing support pin 213 is supported in a state where it passes through the pin sliding hole 222 of the clutch counterweight 220 and is sandwiched by the side plate 214 mounted on the front end of the swing support pin 213.

The side plate 214 is a part for preventing the three clutch weights 220 from being separated from the swing support pins 213. The side plate 214 is formed into a ring shape by metal material. The side plate 214 is arranged on the opposite side of the drive plate 210 relative to the three clutch weights 220 so as to face each clutch weight 220.

The counterweight push body support part 215 is a part for supporting the counterweight push body 216 in a freely rotatable state, and is composed of a stepped rod body made of metal. The counterweight push body support part 215 is formed to protrude in a pin shape on the flange part 212 opposite to the portion of the clutch counterweight 220 closer to the front end side of the clutch counterweight 220 than the pin sliding hole 222. The counterweight push body 216 is a part for pushing the clutch counterweight 220 toward the clutch housing 230 side, and is formed by forming a resin material into a cylindrical shape.

The three clutch counterweights 220 are used to contact or separate relative to the clutch housing 230 through the clutch shoe 221 according to the number of revolutions of the drive plate 210, thereby transmitting the rotational driving force from the engine to the drive shaft 145 or blocking it. The parts are formed by forming a metal material (e.g., zinc) into a curved shape extending along the circumferential direction of the drive plate 210.

The clutch shoe 221 is a component for increasing the friction force on the inner peripheral surface of the clutch housing 230, and is formed by forming the friction material into a plate shape extending in an arc shape. The clutch shoe 221 is provided in a state of being attached to the outer peripheral surface of the front end side of the clutch counterweight 220 of the aforementioned other end side among the clutch counterweights 220.

The clutch counterweight 220 is formed with a pin sliding hole 222 formed of a long hole-shaped through hole at one end side, and is supported by the swing support pin 213 to rotate freely through the pin sliding hole 222. In addition, each clutch counterweight 220 is connected to the clutch counterweight 220 adjacent to each other at the other end side by a connecting spring 223, and is pulled toward the inner side of the driving plate 210. That is, the clutch counterweight 220 is supported on the driving plate 210 through the swing support pin 213 and the pin sliding hole 222 in a manner that the other end side of the clutch shoe 221 is swung relative to the clutch housing 230.

The connecting spring 223 is a component used to apply tension to the clutch counterweight 220 to pull the other end sideways in a direction away from the clutch housing 230, and is composed of a metal coil spring. The connecting spring 223 is respectively mounted between the clutch counterweights 220 adjacent to each other along the circumferential direction of the driving plate 210.

In addition, a pressing body accommodating portion 224 is formed on the inner side surface of each clutch counterweight 220 facing the drive plate 210. The pressing body accommodating portion 224 is a portion that accommodates the counterweight pressing body 216 and is formed with a pressing body supporting portion 224a pressed by the counterweight pressing body 216, and is formed by cutting a concave shape on the inner side surface of the clutch counterweight 220.

The pressing body support portion 224a is used to displace the clutch counterweight 220 to the side of the clutch housing 230 by being pressed by the counterweight pressing body 216. The pressing body support portion 224a is formed by a smooth curved surface that bends and extends toward the rear and outside of the rotational driving direction of the driving plate 210 from the side surface inside the pressing body accommodating portion 224.

The clutch housing 230 is a component that is rotationally driven integrally with the drive shaft 145, and is formed by forming a metal material into a cup shape that covers the outer peripheral surface of the clutch counterweight 220 from the drive plate 210. That is, the clutch housing 230 is formed to have a cylindrical surface 231, and the cylindrical surface 231 is in friction contact with the clutch shoe 221 of the clutch counterweight 220 that is displaced to the outer peripheral side of the drive plate 210.

(Operation of the pulley device 130 and the centrifugal clutch 200) Next, the operation of the pulley device 130 and the centrifugal clutch 200 constructed in the above manner is described. The centrifugal clutch 200 functions as a part of the power transmission mechanism 100, which is arranged between the engine and the rear wheel as the driving wheel in a two-wheeled motor vehicle (such as a scooter). First, when the engine is in an idling state, as shown in FIG1, the centrifugal clutch 200 blocks the transmission of driving force between the engine and the drive shaft 145.

Specifically, in the pulley device 130, the driven pulley 131 is driven to rotate by the rotational driving force of the engine transmitted through the driving pulley 110 and the V-belt 120. Here, in the driven pulley 131, the movable side driven plate 150 is connected to the fixed side driven plate 140 through the sliding sleeve 153, and the fixed side driven plate 140 is directly connected to the driving plate 210. Thereby, the driving plate 210 is driven to rotate at the same number of revolutions as the fixed side driven plate 140 and the movable side driven plate 150. That is, the three clutch counterweights 220 disposed on the driving plate 210 in the centrifugal clutch 200 are rotationally driven at the same speed as the driving plate 210.

However, in this case, the centrifugal force acting on the clutch counterweight 220 in the centrifugal clutch 200 is smaller than the elastic force (tension) of the connecting spring 223, so the clutch counterweight 220 will not tilt toward the cylindrical surface 231 of the clutch housing 230 to the extent that the clutch shoe 221 contacts the cylindrical surface 231 of the clutch housing 230. Therefore, the rotational driving force of the engine will not be transmitted to the drive shaft 145, and the centrifugal clutch 200 will be in the clutch disengaged state.

In the clutch disengaged state, in the driven pulley 131, the movable side driven plate 150 is elastically pressed by the torsion spring 155 to a position closest to the fixed side driven plate 140 or a position near the fixed side driven plate 140. Therefore, the movable side driven plate 150 transmits the rotational driving force to the fixed side driven plate 140 in a state where the convex cam portion 154 in the sliding sleeve 153 is fitted deep into the concave cam portion 144 formed in the fixed side sleeve 142 of the fixed side driven plate 140. That is, the movable side driven plate 150 transmits the rotational driving force when the contact area between the convex cam portion 154 and the concave cam portion 144 is the largest or close to the largest contact area, so when the engine speed tends to be unstable and low, the rotational driving force can be stably transmitted to the fixed side driven plate 140.

Next, the centrifugal clutch 200 transmits the rotational driving force of the engine to the drive shaft 145 according to the increase in engine speed caused by the throttle operation of the driver in the two-wheeled motor vehicle. Specifically, in the centrifugal clutch 200, as the engine speed increases, the centrifugal force acting on the clutch counterweight 220 will be greater than the elastic force (tension) of the connecting spring 223, and the clutch counterweight 220 will rotate and displace radially outward with the swing support pin 213 as the center.

That is, in the centrifugal clutch 200, as the engine speed increases, the clutch counterweight 220 will resist the elastic force (tension) of the connecting spring 223 while rotating and displacing toward the cylindrical surface 231 of the clutch housing 230, and as a result, the clutch shoe 221 will contact the cylindrical surface 231.

Thus, the clutch counterweight 220 receives a reaction force in the opposite direction of the rotational driving direction through the clutch shoe 221, and is relatively displaced in the opposite direction of the rotational driving direction of the driving plate 210. In this case, as the push body support portion 224a causes the counterweight push body 216 to rotate and displace while climbing up the counterweight push body 216, the clutch counterweight 220 is pushed toward the radially outward side of the clutch housing 230, and the clutch shoe 221 is strongly pressed against the cylindrical surface 231.

That is, in the centrifugal clutch 200, after the clutch shoe 221 contacts the cylindrical surface 231 of the clutch housing 230, in a very short time (in other words, an instant), the clutch shoe 221 is pushed against the cylindrical surface 231 and the clutch counterweight 220 is wedge-shapedly embedded between the counterweight pushing body 216 and the clutch housing 230. Thereby, the centrifugal clutch 200 becomes a clutch engagement state that completely transmits the rotational driving force of the engine to the drive shaft 145. Therefore, the two-wheeled motor vehicle can drive the rear wheels to rotate by the rotational driving force of the engine.

In the process of shifting to the clutch engagement state, in the driven pulley 131, as the engine speed increases, the movable side driven plate 150 resists the elastic force of the torsion spring 155 and moves to the side separated from the fixed side driven plate 140. In this case, the movable side driven plate 150 is separated from the fixed side driven plate 140 by the sliding sleeve 153 installed on the movable side sleeve 152 sliding on the fixed side sleeve 142 to the left side in the figure.

Therefore, the convex cam portion 154 formed on the sliding sleeve 153 is slidably displaced to the left side of the figure relative to the concave cam portion 144 formed on the fixed side driven plate 140. As a result, the amount of engagement between the cam forming protrusion 143 and the concave cam portion 144 formed on the fixed side driven plate 140 and the cam forming notch portion 153b and the convex cam portion 154 is reduced and exposed on the V-belt 120 side. That is, the movable side driven plate 150 transmits the rotational driving force to the fixed side driven plate 140 when the contact area between the convex cam portion 154 and the concave cam portion 144 is minimum or close to the minimum.

On the other hand, when the engine speed decreases, the centrifugal clutch 200 blocks the engine's rotational driving force from being transmitted to the drive shaft 145. Specifically, in the centrifugal clutch 200, as the engine speed decreases, the centrifugal force acting on the clutch counterweight 220 becomes smaller than the elastic force (tension) of the connecting spring 223, and the clutch counterweight 220 rotates and displaces radially inward with the swing support pin 213 as the center.

Thus, in the clutch counterweight 220, the clutch shoe 221 is separated from the cylindrical surface 231 of the clutch housing 230 and returns to the original position (the aforementioned position at idle speed). That is, the centrifugal clutch 200 becomes a clutch separation state in which the clutch shoe 221 does not contact the clutch housing 230 and does not transmit the rotational driving force.

In this case, in the driven pulley 131, as the engine speed decreases, the movable side driven plate 150 is displaced by the elastic force of the torsion spring 155 so as to approach the fixed side driven plate 140. In this case, the movable side driven plate 150 slides on the fixed side sleeve 142 to the right side in the figure by the sliding sleeve 153 installed on the movable side sleeve 152, so as to approach the fixed side driven plate 140. Thereby, the concave cam portion 144 formed on the fixed side driven plate 140 is displaced to the right side in the figure by the convex cam portion 154 formed on the movable side driven plate 150, and the amount of engagement with the convex cam portion 154 is increased, and the amount of exposure is reduced.

As can be understood from the above operation description, according to the above first embodiment, in the pulley device 130, the cylindrical sliding sleeve 153 that is displaced integrally with the movable side sleeve 152 relative to the fixed side sleeve 142 is provided with a convex cam portion 154 that engages with the concave cam portion 144 formed on the fixed side sleeve 142, and the sliding sleeve 153 is directly slidably displaced relative to the fixed side sleeve 142. Thus, according to the pulley device 130 of the present invention, the sliding sleeve 153 can be displaced smoothly compared to the case where the sliding sleeve 153 is displaced through the movable side sleeve 152. Furthermore, according to the pulley device 130 of the present invention, a convex cam portion 154 is formed on the sliding sleeve 153, thereby reducing the number of parts and achieving miniaturization, lightness and reduced manufacturing burden of the pulley device 130 and the centrifugal clutch 200.

Furthermore, when implementing the present invention, it is not limited to the above-mentioned first embodiment, and various changes can be made as long as they do not deviate from the purpose of the present invention.

For example, in the first embodiment, the pulley device 130 is configured by forming a concave cam portion 144 on the fixed-side sleeve 142 of the fixed-side driven plate 140, and forming a convex cam portion 154 protruding radially inwardly on the movable-side sleeve 152 of the movable-side driven plate 150. However, the pulley device 130 may also be configured by forming a convex cam portion 154 protruding radially outwardly on the fixed-side sleeve 142 of the fixed-side driven plate 140, and forming a concave cam portion 144 on the sliding sleeve 153. In this case, the pulley device 130 is formed by forming a groove-shaped or through-hole-shaped cam-forming notch 153 b on the fixed-side sleeve 142 of the fixed-side driven plate 140 , and forming a cam-forming protrusion 143 on the sliding sleeve 153 .

That is, the concave cam portion 144 may be formed by extending spirally through a hole-shaped or groove-shaped cutout in one of the fixed-side sleeve 142 and the sliding sleeve 153. In this case, the convex cam portion 154 may be formed by radially protruding from the other of the fixed-side sleeve 142 and the sliding sleeve 153 and slidably fitting into the concave cam portion 144.

Furthermore, in the first embodiment, the concave cam portion 144 is formed in a groove shape with a bottom. However, the concave cam portion 144 may be formed in a through hole that penetrates the fixed side sleeve 142 and extends in a spiral shape in the axial direction of the fixed side sleeve 142. Accordingly, the pulley device 130 is formed with the concave cam portion 144 in the shape of a through hole on the fixed side sleeve 142, so that the ventilation of the interior of the fixed side sleeve 142 can be ensured, the heat dissipation can be improved, and the durability can be improved. In addition, the concave cam portion 144 may also be formed in the shape of a through hole when formed on the sliding sleeve 153.

Furthermore, in the first embodiment, the concave cam portion 144 is formed by the cam forming protrusion 143 formed on the outer peripheral surface of the fixed side sleeve 142. Thus, the concave cam portion 144 allows the cam forming protrusion 143 to function as a rib for thickening the thickness of the fixed side sleeve 142, thereby improving rigidity and durability. However, the concave cam portion 144 may also be formed in a groove shape or a through hole shape that is concavely recessed from the surface of the outer peripheral surface of the fixed side sleeve 142.

Furthermore, in the first embodiment, the convex cam portion 154 is formed to protrude in a spiral shape in the axial direction at the end of the sliding sleeve 153. Thus, the convex cam portion 154 is formed to protrude from the inner peripheral surface of the movable side sleeve 152 in a sliding rail shape. However, the convex cam portion 154 only needs to be formed in a manner that protrudes from the inner peripheral surface of the movable side sleeve 152 in a convex shape and is slidably fitted into the concave cam portion 144. Therefore, the convex cam portion 154 may be formed in a pin shape formed in a rod shape, for example.

Furthermore, in the first embodiment, the sliding sleeve 153 is made of a resin material, and the fixed-side sleeve 142 is made of a metal material. That is, the pulley device 130 is made of the sliding sleeve 153 and the fixed-side sleeve 142 with different materials. Thus, the pulley device 130 can improve the sliding performance between the sliding sleeve 153 and the fixed-side sleeve 142 and between the concave cam portion 144 and the convex cam portion 154, and suppress wear degradation. However, the pulley device 130 can also make the sliding sleeve 153 and the fixed-side sleeve 142 with the same material. Furthermore, the pulley device 130 can also make the sliding sleeve 153 and the fixed-side sleeve 142 with materials other than the resin material and the metal material, for example, ceramic material.

<Second embodiment> Next, the second embodiment of the pulley device of the present invention and the centrifugal clutch having the pulley device will be described with reference to FIGS. 3 to 6 respectively. In the first embodiment described above, the sliding sleeve 153 in the pulley device 130 is configured as follows: it is formed into a cylindrical shape between the fixed side sleeve 142 and the movable side sleeve 152 and is displaced integrally with the movable side sleeve 152, and slides relative to the fixed side sleeve 142. On the other hand, in the second embodiment, the sliding sleeve 160 in the pulley device 130 is formed into a cylindrical shape between the fixed side sleeve 142 and the movable side sleeve 152, and cannot be relatively displaced relative to the fixed side sleeve 142, and relatively slides relative to the movable side sleeve 152, which is different from the first embodiment.

Therefore, in the pulley device 130 and the centrifugal clutch 200 in the second embodiment, the parts different from the pulley device 130 and the centrifugal clutch 200 in the first embodiment are mainly described, and the common parts and corresponding parts in the two embodiments are appropriately omitted. In addition, in FIG. 3, the diagram of the structure of the drive pulley 110 side in the speed changer 101 is omitted. 3, similarly to FIG. 1 in the first embodiment, the upper half of each of the pulley device 130 and the centrifugal clutch 200 shows a state where the movable side driven plate 150 is closest to the fixed side driven plate 140, and the lower half of each of the figures shows a state where the movable side driven plate 150 is most separated from the fixed side driven plate 140.

(Structure of pulley device 130 and centrifugal clutch 200)

Similar to the pulley device 130 in the first embodiment, the pulley device 130 is composed of a driven pulley 131 having a fixed side driven plate 140 and a movable side driven plate 150.

The fixed side driven plate 140 is constituted by a fixed side plate 141 and a fixed side sleeve 142 respectively identical to the fixed side plate 141 and the fixed side sleeve 142 in the first embodiment. In this case, the fixed side sleeve 142 does not form the cam-forming protrusion 143 and the concave cam portion 144 in the first embodiment, which is different from the first embodiment.

As shown in FIG. 4 , the movable side driven plate 150 is constituted by a movable side plate 151 and a movable side sleeve 152 respectively identical to the movable side plate 151 and the movable side sleeve 152 in the first embodiment. In this case, the movable side sleeve 152 is formed with a concave cam portion 156 at the end portion on the driving plate 210 side to replace the cam connection portion 152a in the first embodiment.

The concave cam portion 156 is formed in a portion that is fitted with the convex cam portion of the sliding sleeve 160 described below in a freely sliding state, and is formed in a spiral shape that is twisted in the circumferential direction and extends in the axial direction at the illustrated left end portion in the movable side sleeve 152. In this case, the concave cam portion 156 is formed by cutting while being radially through. In addition, three concave cam portions 156 are formed at equal intervals in the circumferential direction of the movable side sleeve 152.

That is, the concave cam portions 156 are formed between the three uncut concave cam forming portions 157 at the end of the movable side sleeve 152. Each of the concave cam portions 156 is formed in the following manner: the thickness is formed to be thinner than the annular gap S formed in the outer side cylinder portion 162 of the sliding sleeve 160, and does not contact the radial inner and outer side walls in the outer side cylinder portion. In addition, the concave cam portion 156 can also be formed in the outer peripheral portion of the sliding sleeve 160 as a groove with a bottom instead of a through hole. Moreover, it is sufficient as long as at least one concave cam portion 156 is formed relative to the sliding sleeve 160. Furthermore, the concave cam portion 156 may also be formed to contact the radially inner and outer side walls of the outer tube portion.

The sliding sleeve 160 is shown in FIG. 5 and FIG. 6 respectively. It is disposed between the fixed side sleeve 142 and the movable side sleeve 152 so that the movable side sleeve 152 slides relative to the fixed side sleeve 142, and is used to form a convex cam part that engages with the aforementioned concave cam part 156. It is formed by forming a resin material into a cylindrical shape. In this case, the sliding sleeve 160 can be formed of the same resin material as the sliding sleeve 153 in the above-mentioned embodiment. The sliding sleeve 160 is mainly composed of a body 161 and an outer cylinder 162.

The main body 161 is a portion that is fitted to the outer circumference of the fixed side sleeve 142 in the fixed side driven plate 140 in a state where the fixed side sleeve 142 cannot be relatively displaced, and is fitted to the movable side sleeve 152 of the movable side driven plate 150 in a state where the movable side sleeve 152 can slide freely, and is formed in a cylindrical shape. The outer side cylinder 162 is a portion that forms a convex cam portion 165, and is formed in a cylindrical shape that covers the end portion of the main body 161 on the driving plate 210 side with a gap S therebetween.

In this case, the annular gap S formed on the inner side of the outer tube portion 162 is a portion where the convex cam portion 165 is formed and the concave cam portion 156 and the concave cam forming portion 157 are respectively inserted. In addition, the outer peripheral portion of the outer tube portion 162 is formed with a spring support portion 163 and a plate fitting portion 164 at the end portion on the driving plate 210 side. Then, the portion of the outer tube portion 162 closer to the movable side plate 151 side than the spring support portion 163 covers the outer side of the concave cam forming portion 157 to prevent contact with the torsion spring 155.

The spring support portion 163 is a portion that supports the end portion of the torsion spring 155 on the drive plate 210 side, and is formed to protrude radially outward from the outer peripheral portion of the outer cylindrical portion 162 in a flange shape. The plate fitting portion 164 is a portion that is used to fit into the sleeve fitting hole 217 formed in the drive plate 210 to rotate and drive the sliding sleeve 160 and the drive plate 210 as a whole, and is formed in a state of protruding from the end of the body portion 161 and the end surface of the spring support portion 163, respectively.

In this embodiment, three plate fitting parts 164 are formed at equal intervals along the circumferential direction of the spring support part 163. That is, the sliding sleeve 160 is rotationally driven integrally with the driving plate 210 and the fixed-side driven plate 140 by fitting the plate fitting parts 164 with the sleeve fitting holes 217 formed in the driving plate 210. In addition, a through hole is formed in the plate fitting part 164, and the concave cam forming part 157 formed in the movable-side sleeve 152 can pass through the through hole.

The convex cam portion 165 is formed in a portion that is slidably engaged with the concave cam portion 156 of the movable side sleeve 152, and is formed in a protruding state in the space between the main body portion 161 and the outer side cylinder portion 162 in the sliding sleeve 160. In this case, the convex cam portion 165 is formed to extend in a spiral shape in the axial direction of the sliding sleeve 160. In addition, three convex cam portions 165 are formed at equal intervals in the circumferential direction of the sliding sleeve 160.

That is, between the three convex cam portions 165, the cam forming notches 166 for forming the convex cam portions 165 are respectively extended in a spiral shape. Then, the three cam forming notches 166 are slidably engaged with the concave cam forming portion 157 formed on the movable side sleeve 152. Therefore, the concave cam forming portion 157 formed on the movable side sleeve 152 can be regarded as the convex cam portion of the present invention formed on the sliding sleeve 160, and the cam forming notches 166 formed on the sliding sleeve 160 can also be regarded as the concave cam portion of the present invention formed on the sliding sleeve 160. In addition, the cam-forming notch portion 166 can also be constructed in a manner of contacting the outer periphery of the main body 161 and the inner periphery of the outer tube portion 162 of the sliding sleeve 160, but in the present embodiment, it is constructed in a non-contact manner relative to the outer periphery of the main body 161 and the inner periphery of the outer tube portion 162, respectively.

On the driving plate 210, a sleeve fitting hole 217 is formed outside the inner tooth-shaped bolt groove in the bottom 211 where the fixed side sleeve 142 fits. The sleeve fitting hole 217 is a through hole into which the three plate fitting parts 164 of the sliding sleeve 160 fit, and three sleeve fitting holes 217 are formed at equal intervals along the circumferential direction of the driving plate 210.

(Operation of the pulley device 130 and the centrifugal clutch 200) Next, the operation of the pulley device 130 and the centrifugal clutch 200 constructed in the above manner will be described.

First, when the centrifugal clutch 200 is in the clutch disengagement state, the movable side driven plate 150 in the driven pulley 131 is elastically pushed by the torsion spring 155 to a position closest to the fixed side driven plate 140 or a position near it. In this case, the movable side sleeve 152 slides on the main body 161 of the sliding sleeve 160 and the movable side driven plate 150 is elastically pushed to the side of the fixed side driven plate 140. Therefore, the movable side driven plate 150 transmits the rotational driving force to the driving plate 210 in a state where the convex cam portion 165 formed on the sliding sleeve 160 is engaged with the concave cam portion 156 with a minimum or nearly minimum contact area.

Next, when the centrifugal clutch 200 is transferred to the clutch engagement state, in the driven pulley 131, as the engine speed increases, the movable side driven plate 150 resists the elastic force of the torsion spring 155 and moves to the side separated from the fixed side driven plate 140. In this case, the movable side driven plate 150 is separated from the fixed side driven plate 140 by the movable side sleeve 152 sliding on the sliding sleeve 160 to the left side in the figure.

Therefore, the concave cam portion 156 and the concave cam forming portion 157 formed on the movable side sleeve 152 become deep into the sliding sleeve 160. Thereby, the movable side driven plate 150 transmits the rotational driving force to the driving plate 210 when the contact area between the convex cam portion 165 and the concave cam portion 156 is maximum or close to the maximum contact area.

On the other hand, when the engine speed decreases, in the driven pulley 131, as the engine speed decreases, the movable side driven plate 150 is displaced by the elastic force of the torsion spring 155 so as to approach the fixed side driven plate 140. In this case, the movable side driven plate 150 slides on the sliding sleeve 160 to the right side in the figure and approaches the fixed side driven plate 140. Thereby, the convex cam portion 165 formed on the sliding sleeve 160 transmits the rotational driving force of the movable side driven plate 150 to the driving plate 210 in a state where the engagement amount with the concave cam portion 156 is reduced due to the concave cam portion 156 formed on the movable side driven plate 150 slidingly displaced to the right side as shown in the figure.

As can be understood from the above operation description, according to the above second embodiment, in the pulley device 130, a convex cam portion 165 engaging with the concave cam portion 156 formed on the movable side sleeve 152 is formed on the cylindrical sliding sleeve 160 that is set so as not to be rotationally displaced relative to the fixed side sleeve 142, and the movable side sleeve 152 directly slides and displaces on the sliding sleeve 160. Thus, according to the pulley device 130 of the present invention, the cam mechanism composed of the convex cam portion 165 and the concave cam portion 156 can operate smoothly. Furthermore, according to the pulley device 130 of the present invention, a convex cam portion 165 is formed on the sliding sleeve 160, thereby reducing the number of parts and achieving miniaturization, lightness and reduced manufacturing burden of the pulley device 130.

Furthermore, when implementing the present invention, it is not limited to the above-mentioned second embodiment, and various changes can be made as long as they do not deviate from the purpose of the present invention.

For example, in the second embodiment described above, the pulley device 130 is configured by forming the concave cam portion 156 on the movable side sleeve 152 and forming the convex cam portion 165 on the sliding sleeve 160. However, the pulley device 130 may be configured by forming the convex cam portion 165 on the movable side sleeve 152 and forming the concave cam portion 156 on the sliding sleeve 160. In this case, the convex cam portion 165 having the same shape as the concave cam forming portion 157 may be formed on the movable side sleeve 152, and the cam forming notch portion 166 having the same shape as the concave cam portion 156 may be formed between the convex cam portions 165. Furthermore, a concave cam portion 156 having the same shape as the cam forming notch portion 166 may be formed on the sliding sleeve 160 , and a concave cam forming portion 157 having the same shape as the convex cam portion 165 may be formed between the concave cam portions 156 .

That is, the concave cam portion 156 may be formed by extending in a spiral shape and passing through a hole-shaped or groove-shaped cutout in one of the movable side sleeve 152 and the sliding sleeve 160. In this case, the convex cam portion 165 may be formed by radially protruding in the other of the movable side sleeve 152 and the sliding sleeve 160 and slidably fitting in the concave cam portion 156.

In the second embodiment, the concave cam portion 156 is formed by cutting through the movable sleeve 152. However, the concave cam portion 156 may be formed as a groove having a bottom on the outer circumference or a top on the inner circumference of the movable sleeve 152. In this case, the convex cam portion 165 may be formed so that the protrusion from the inner circumference of the outer tube portion 162 in the sliding sleeve 160 does not reach the main body 161, or the protrusion from the outer circumference of the main body 161 does not reach the inner circumference of the outer tube portion 162.

Moreover, the concave cam portion 156 may be formed at a position protruding from the outer peripheral surface of the movable side sleeve 152, like the concave cam portion 144 in the first embodiment. That is, the concave cam portion 156 may be formed by forming at least two cam forming protrusions 143 in the first embodiment on the outer peripheral surface of the movable side sleeve 152, and forming a concave cam portion 156 similar to the concave cam portion 144 between the two cam forming protrusions 143.

Furthermore, in the second embodiment, the convex cam portion 165 is formed in a spiral shape while being mounted between the main body portion 161 and the outer tube portion 162 of the sliding sleeve 160. However, the convex cam portion 165 may be formed so as to be slidably fitted into the concave cam portion 156. Therefore, the convex cam portion 165 may be formed in a pin shape formed in a rod shape, for example.

In the second embodiment, the sliding sleeve 160 is configured by having the outer tube portion 162 on the outer side of the body portion 161. Thus, the sliding sleeve 160 can prevent foreign matter from entering the cam engagement portion where the concave cam portion 156 and the convex cam portion 165 are cam-engaged, and prevent the torsion spring 155 from contacting the concave cam portion 156 and the convex cam portion 165, thereby maintaining smooth cam engagement for a long period of time. However, the sliding sleeve 160 can also be configured by omitting the outer tube portion 162.

In the second embodiment, the sliding sleeve 160 is connected to the sleeve fitting hole 217 of the driving plate 210. However, the sliding sleeve 160 may be configured to be rotationally driven integrally with the fixed-side driven plate 140 and the driving plate 210. Therefore, the sliding sleeve 160 may be mounted on the fixed-side sleeve 142 in the fixed-side driven plate 140, for example.

Furthermore, in the second embodiment described above, the sliding sleeve 160 is made of a resin material, and the movable side sleeve 152 is made of a metal material. That is, the pulley device 130 is made of the sliding sleeve 160 and the movable side sleeve 152 with different materials. Thereby, the pulley device 130 can improve the sliding property between the sliding sleeve 160 and the movable side sleeve 152 and between the concave cam portion 156 and the convex cam portion 165, and suppress wear degradation. However, the pulley device 130 can also make the sliding sleeve 160 and the movable side sleeve 152 with the same material. Furthermore, the pulley device 130 can also make the sliding sleeve 160 and the movable side sleeve 152 with materials other than the resin material and the metal material, for example, ceramic material.

In the above-mentioned embodiments, the pulley device 130 is configured by forming three concave cam portions 144, 156 and three convex cam portions 154, 165. However, the pulley device 130 only needs to form at least one set of concave cam portions 144, 156 and three convex cam portions 154, 165.

Furthermore, in the above-mentioned embodiment, the centrifugal clutch 200 is configured by respectively having a counterweight pressing body 216, a pressing body accommodating portion 224, and a pressing body supporting portion 224a. However, the centrifugal clutch 200 may also be configured by omitting the counterweight pressing body 216, the pressing body accommodating portion 224, and the pressing body supporting portion 224a. Furthermore, the centrifugal clutch 200 forms the pin sliding hole 222 in a long hole shape when viewed from above. However, the centrifugal clutch 200 may also form the pin sliding hole 222 in a circular shape when viewed from above.

In the above-mentioned embodiment, the pulley device 130 is applied to the centrifugal clutch 200. However, the pulley device 130 can be widely applied to a mechanical device that transmits a driving force from a driving source such as an engine or an electric motor to an output shaft such as a driving shaft 145. Therefore, the pulley device 130 can also be applied to a multi-plate clutch, for example, which transmits or blocks a rotational driving force by pressing two plates arranged opposite to each other, specifically, a multi-plate friction plate having a friction material on the surface of a flat ring-shaped core plate and a multi-plate clutch plate without a friction material. Furthermore, the pulley device 130 can also be provided as a part of the driving force transmission mechanism between the electric motor and the driving wheel in an electric vehicle that uses the electric motor as a driving source.

S: Annular gap

100: Power transmission mechanism

101: Transmission

110: Driving pulley

111: Crankshaft

112:Fix the drive plate

112a: Heat sink

113: Movable drive plate

114: Sleeve bearing

115: Roller counterweight

116: Ramp board

120: V-belt

130:Pulley device

131: Driven pulley

140: Fixed side follower plate

141:Fixed side panels

142: Fixed side sleeve

143: Cam forming protrusion

144: Concave cam

145: Drive shaft

146a,146b: Bearing

150: Movable side driven plate

151: Movable side panel

152: Movable side sleeve

152a: Cam connection part

153: Sliding sleeve

153a: sleeve connection part

153b: Cam forming notch

154: convex cam part

155: Torsion spring

156: Concave cam

157: Concave cam forming portion

160: Sliding sleeve

161: Headquarters

162: Outer tube

163: Spring support

164: Plate fitting part

165: convex cam part

166: Cam forming notch

200: Centrifugal Clutch

210:Drive board

211: Bottom

212: Edge

213: Swing support pin

213a: Mounting bolts

214:Side panel

215: Counterweight pusher support

216: Counterweight pusher

217: Sleeve fitting hole

220:Clutch weight

221: Clutch shoe

222: Pin sliding hole

223: Link spring

224: Pushing body accommodating portion

224a: Pushing body support portion

230: Clutch housing

231: Cylindrical surface

FIG. 1 is a top view schematically showing the structure of a power transmission mechanism of a pulley device and a centrifugal clutch having the first embodiment of the present invention. FIG. 2 is an assembly exploded perspective view schematically showing the external appearance structure of a fixed side driven plate, a movable side driven plate, and a cam forming cylinder constituting the pulley device shown in FIG. 1. FIG. 3 is a top view schematically showing the structure of a power transmission mechanism of a pulley device and a centrifugal clutch having the second embodiment of the present invention. FIG. 4 is a perspective view schematically showing the external appearance structure of a movable side driven plate constituting the pulley device shown in FIG. 3. FIG. 5 is a perspective view showing a schematic external appearance of the sliding sleeve constituting the pulley device shown in FIG. 3 as viewed from the main body side. FIG. 6 is a perspective view showing a schematic external appearance of the sliding sleeve constituting the pulley device shown in FIG. 3 as viewed from the plate fitting side.

100: Power transmission mechanism

101: Transmission

110: Driving pulley

111: Crankshaft

112:Fix the drive plate

112a: Heat sink

113: Movable drive plate

114: Sleeve bearing

115: Roller counterweight

116: Ramp board

120: V-belt

130:Pulley device

131: Driven pulley

140: Fixed side follower plate

141:Fixed side panels

142: Fixed side sleeve

143: Cam forming protrusion

144: Concave cam portion

145: Drive shaft

146a,146b: Bearings

150: Movable side follower plate

151: Movable side panel

152: Movable side sleeve

152a: Cam connection part

153: Sliding sleeve

153a: Sleeve connection part

153b: Cam forming notch

154: convex cam part

155: Torsion spring

200: Centrifugal clutch

210:Drive board

211: Bottom

212: Edge

213: Swing support pin

213a: Mounting bolts

214:Side panel

215: Counterweight pusher support part

216: Counterweight pusher

220: Clutch weight

221: Clutch shoe

222: Pin sliding hole

223: Connecting spring

224: Pushing body accommodating part

224a: Pushing body support part

230: Clutch housing

231: Cylindrical surface

Claims (9)

A pulley device is characterized by comprising: a fixed side driven plate, which has a fixed side plate protruding radially outward in a flange shape on the outer peripheral surface of a fixed side sleeve formed in a cylindrical shape, and is rotationally driven by receiving a driving force from a driving source through a belt; a movable side driven plate, which has a movable side plate protruding radially outward in a flange shape on the outer peripheral surface of a movable side sleeve formed in a cylindrical shape and clamps the belt together with the fixed side plate, and is rotationally driven by receiving a driving force from the driving source through the belt while approaching or separating from the fixed side plate; and a sliding sleeve, The cylindrical part is disposed between the fixed side sleeve and the movable side sleeve and displaced integrally with the movable side sleeve and slides relatively to the fixed side sleeve; the concave cam part is formed by cutting along the axial spiral shape in one of the sliding sleeve and the fixed side sleeve; and the convex cam part is slidably engaged in the concave cam part in the other of the sliding sleeve and the fixed side sleeve, and the concave cam part or the convex cam part formed in the sliding sleeve is formed by extending in the axial direction at one end of the sliding sleeve. As in claim 1, the pulley device, wherein the aforementioned concave cam portion or the aforementioned convex cam portion formed on the aforementioned sliding sleeve is non-contacting with respect to the outer peripheral surface of the aforementioned fixed side sleeve. As in claim 1 or 2, the pulley device, wherein the movable side sleeve is formed with a cam connection portion, and the cam connection portion is formed in a concave or convex shape; the sliding sleeve is formed with a convex or concave sleeve connection portion that fits with the cam connection portion. A pulley device as claimed in claim 1 or 2, wherein the sliding sleeve and the fixed side sleeve are made of different materials. A centrifugal clutch, characterized by having: a pulley device as in any one of claims 1 to 4; a drive plate connected to the fixed side sleeve and rotationally driven integrally with the fixed side driven plate; a clutch housing having a cylindrical surface arranged concentrically with the drive plate on the outer side of the drive plate and connected to the drive shaft; and a clutch counterweight extending along the circumferential direction of the drive plate and having a clutch shoe facing the cylindrical surface of the clutch housing, one end side of the circumferential direction of which is rotatably mounted on the drive plate, and the other end side of which is displaced toward the cylindrical surface of the clutch housing. A pulley device is characterized by comprising: a fixed side driven plate, which has a fixed side plate protruding outwardly in a flange shape on the outer peripheral surface of a cylindrical fixed side sleeve, and is driven to rotate by receiving a driving force from a driving source through a belt; a movable side driven plate, which has a movable side plate protruding outwardly in a flange shape on the outer peripheral surface of a cylindrical movable side sleeve and clamps the belt together with the fixed side plate, and is driven to rotate by receiving a driving force from the driving source through the belt while approaching or separating from the fixed side plate; a sliding sleeve, which has a fixed side driven plate provided between the fixed side sleeve and the movable side sleeve The cylindrical body is arranged to be non-displaceable relative to the fixed side sleeve and slides relative to the movable side sleeve; the concave cam is formed by cutting along the axial spiral shape in one of the sliding sleeve and the movable side sleeve; and the convex cam is slidably fitted in the concave cam in the other of the sliding sleeve and the movable side sleeve, the concave cam or the convex cam is formed on the outside of the body in the sliding sleeve, and the sliding sleeve has an outer cylindrical portion in a state of covering the concave cam or the convex cam formed on the outside of the body. As in claim 6, the pulley device, wherein the sliding sleeve and the movable side sleeve are made of different materials. A centrifugal clutch is characterized by having: a pulley device as claimed in claim 6 or 7; a driving plate connected to the fixed side sleeve and rotationally driven integrally with the fixed side driven plate; a clutch housing having a cylindrical surface arranged concentrically with the driving plate on the outer side of the driving plate and connected to the driving shaft; and a clutch counterweight extending along the circumferential direction of the driving plate and having a clutch shoe facing the cylindrical surface of the clutch housing, one end side of the circumferential direction of the clutch shoe being rotatably mounted on the driving plate, and the other end side being displaced toward the cylindrical surface of the clutch housing. As in claim 8, the centrifugal clutch, wherein the sliding sleeve is disposed on the driving plate.