JP7708393B2 - Pulley device and centrifugal clutch - Google Patents

Description

This relates to a pulley device that transmits driving force from a driving source such as an engine, and a centrifugal clutch equipped with the same pulley device.

Conventionally, there are 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 equipped with a pulley device consisting of a pair of fixed sheaves and a movable sheave that receives driving force from the engine via a belt. In this case, the movable sheave is configured to move toward or away from the fixed sheave by fitting a cylindrically formed movable boss to a cylindrical fixed boss formed on the fixed sheave via a cylindrical sliding member. The movable sheave obtains axial thrust by meshing a helical cam portion formed at the tip of the movable boss with a helical cam receiving member provided on a drive plate that rotates integrally with the fixed sheave.

JP 2019-127993 A

However, in the pulley device described in Patent Document 1, the movable sheave slides back and forth on the fixed boss via the sliding member, so if there is a misalignment between the axial direction of the sliding member and the axial direction of the movable boss, unnecessary frictional resistance is generated between the cam portion formed on the movable sheave and the cam receiving member provided on the drive plate, preventing smooth displacement.

The present invention was made to address the above problems, and its purpose is to provide a pulley device that can smoothly operate a cam mechanism that displaces the movable driven plate, which serves as a movable sheave, and a centrifugal clutch equipped with the same pulley device.

In order to achieve the above object, the present invention is characterized by a fixed-side driven plate having a fixed-side plate that protrudes radially outward like a flange on the outer circumferential surface of a cylindrically formed fixed-side sleeve, and that receives a driving force from a driving source via a belt to rotate and drive the plate; a movable-side driven plate having a movable-side plate that protrudes radially outward like a flange on the outer circumferential surface of a cylindrically formed movable-side sleeve and that sandwiches the belt together with the fixed-side plate, and that receives a driving force from a driving source via the belt to rotate and drive the plate while approaching or separating from the fixed-side plate; The fixed-side sleeve has a sliding sleeve that is disposed between the movable-side sleeve and displaces integrally with the movable-side sleeve while sliding relatively on the outer circumferential surface of the fixed-side sleeve, a concave cam portion that is spirally cut out along the axial direction in one of the sliding sleeve and the fixed-side sleeve, and a convex cam portion that slidably fits into the concave cam portion in the other of the sliding sleeve and the fixed-side sleeve, and the concave cam portion or convex cam portion formed in the sliding sleeve is formed to extend in the axial direction at one end of a cylindrical portion of the sliding sleeve that slides relatively on the outer circumferential surface of the fixed-side sleeve .

According to the features of the present invention configured in this way, the pulley device has a cylindrical sliding sleeve that displaces integrally with the movable sleeve relative to the fixed sleeve, and a concave cam portion or convex cam portion that meshes with a convex cam portion or concave cam portion formed on the fixed sleeve is formed on the sliding sleeve, and the sliding sleeve slides and displaces directly relative to the fixed sleeve. As a result, the pulley device according to the present invention can smoothly operate the cam mechanism consisting of the convex cam portion and the concave cam portion. Also, according to the pulley device according to the present invention, the concave cam portion or convex cam portion is formed on the sliding sleeve, thereby reducing the number of parts, making the pulley device smaller, lighter, and less burdensome to manufacture.

Furthermore, according to the features of the present invention configured in this manner, the pulley device has a concave cam portion or a convex cam portion formed on the sliding sleeve that extends axially from one end of the sliding sleeve, which is formed cylindrically, so that the sliding sleeve itself can be configured compactly without increasing the radial size of the sliding sleeve.

Another feature of the present invention is that in the pulley device, the concave cam portion or the convex cam portion formed on the sliding sleeve is not in contact with the main body of the fixed sleeve.

According to another feature of the present invention configured in this manner, the pulley device is configured such that the concave cam portion or convex cam portion formed on the sliding sleeve is not in contact with the main body of the fixed sleeve, thereby reducing frictional resistance during sliding of the sliding sleeve and allowing it to slide smoothly.

Another feature of the present invention is that, in the pulley device, the movable sleeve is formed with a cam connection portion that is formed in a concave or convex shape, and the sliding sleeve is formed with a convex or concave sleeve connection portion that fits into the cam connection portion.

According to another feature of the present invention configured in this manner, the pulley device is connected by fitting the sleeve connection portion formed in a convex or concave shape on the sliding sleeve into the cam connection portion formed in a concave or convex shape on the movable sleeve, thereby making it possible to integrate the sliding sleeve with the movable sleeve with a simple configuration.

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

According to another feature of the present invention configured as above, in the pulley device, the sliding sleeve and the fixed sleeve are made of different materials, so that it is possible to improve the sliding property between them and suppress wear and deterioration. In this case, it is preferable that the sliding sleeve is made of a resin material and the fixed sleeve is made of a metal material.

Furthermore, the present invention can be embodied not only as an invention of a pulley device, but also as an invention of a centrifugal clutch equipped with this pulley device.

Specifically, the centrifugal clutch may comprise the pulley device according to any one of claims 1 to 4, a drive plate connected to the fixed sleeve and rotated integrally with the fixed driven plate, a clutch outer having a cylindrical surface concentric with the drive plate on the outside of the drive plate and connected to the drive shaft, and a clutch weight having a clutch shoe formed to extend along the circumferential direction of the drive plate and facing the cylindrical surface of the clutch outer, one end side in the circumferential direction being rotatably attached to the drive plate and the other end side being displaced toward the cylindrical surface of the clutch outer. With this, the centrifugal clutch can be expected to have the same effects as the above-mentioned pulley device.

The centrifugal clutch includes a fixed-side driven plate having a fixed-side plate that protrudes radially outward like a flange on the outer circumferential surface of a cylindrically formed fixed-side sleeve and that receives a driving force from a driving source via a belt to rotate and drive the fixed-side driven plate, a movable-side plate having a movable-side plate that protrudes radially outward like a flange on the outer circumferential surface of a cylindrically formed movable-side sleeve and that sandwiches the belt with the fixed-side plate, and that receives a driving force from a driving source via the belt while approaching or moving away from the fixed-side plate to rotate and drive the fixed-side driven plate, a sliding sleeve that is formed cylindrically and is provided between the fixed-side sleeve and the movable-side sleeve, is provided so as not to be displaced relative to the fixed-side sleeve and slides relative to the inner circumferential surface of the movable-side sleeve, and a spiral rotatable member that is provided in one of the sliding sleeve and the movable-side sleeve along the axial direction. a pulley device including a fixed-side sleeve having a concave cam portion cut out into a shape corresponding to a movable sleeve and a convex cam portion slidably fitted into the concave cam portion on the other of the sliding sleeve and the movable sleeve; a drive plate connected to the fixed-side sleeve and driven to rotate integrally with the fixed-side driven plate; a clutch outer having a cylindrical surface provided concentrically with the drive plate on the outside of the drive plate and connected to a drive shaft; and a clutch weight having a clutch shoe formed extending along the circumferential direction of the drive plate and facing the cylindrical surface of the clutch outer, one end side in the circumferential direction being rotatably attached to the drive plate and the other end side being displaced toward the cylindrical surface side of the clutch outer, wherein the sliding sleeve may be provided on the drive plate.

According to the features of the present invention configured as described above, the centrifugal clutch has a cylindrical sliding sleeve that is provided so as not to be rotatably displaced relative to the fixed sleeve, and a concave cam portion or a convex cam portion that meshes with a convex cam portion or a concave cam portion formed on the movable sleeve is formed on the cylindrical sliding sleeve, and the movable sleeve directly slides and displaces on the sliding sleeve. As a result, the centrifugal clutch according to the present invention can smoothly operate a cam mechanism consisting of a convex cam portion and a concave cam portion. Also, with the centrifugal clutch according to the present invention, the number of parts is reduced by forming a concave cam portion or a convex cam portion on the sliding sleeve, thereby making it possible to reduce the size and weight of the pulley device and the manufacturing burden.

Another feature of the present invention is that in the centrifugal clutch , the sliding sleeve has a cylindrical main body portion provided between the fixed sleeve and the movable sleeve, and the concave cam portion or the convex cam portion is formed on the outside of the main body portion of the sliding sleeve. According to this other feature of the present invention configured in this way, the centrifugal clutch has the concave cam portion or the convex cam portion formed on the movable sleeve sliding on the main body portion, so that the convex cam portion or the concave cam portion formed on the movable sleeve sliding on the main body portion can be smoothly cam-fitted.

Another feature of the present invention is that in the centrifugal clutch , the sliding sleeve and the movable sleeve are made of different materials. According to this feature of the present invention, the centrifugal clutch has the sliding sleeve and the movable sleeve made of different materials, so that it is possible to improve the sliding properties of the two and suppress wear and deterioration. In this case, it is preferable that the centrifugal clutch has the sliding sleeve made of a resin material and the movable sleeve made of a metal material.

The centrifugal clutch includes a pulley device , a drive plate connected to the fixed sleeve and rotated integrally with the fixed driven plate, a clutch outer having a cylindrical surface concentric with the drive plate on the outside of the drive plate and connected to the drive shaft, and a clutch weight formed to extend along the circumferential direction of the drive plate and having a clutch shoe facing the cylindrical surface of the clutch outer, one end side in the circumferential direction being rotatably attached to the drive plate and the other end side being displaced toward the cylindrical surface of the clutch outer . The pulley device includes a fixed driven plate having a fixed plate that protrudes like a flange radially outward on the outer circumferential surface of the cylindrical fixed sleeve and is rotated by receiving a driving force from a driving source via a belt, and a circular driven plate having a cylindrical plate. The centrifugal clutch includes a movable side driven plate that has a movable side plate that protrudes radially outward like a flange on the outer circumferential surface of a cylindrical movable side sleeve and that sandwiches a belt with the fixed side plate, and receives a driving force from a driving source through the belt while approaching or moving away from the fixed side plate, a sliding sleeve that is formed in a cylindrical shape and is provided between the fixed side sleeve and the movable side sleeve , is formed in a cylindrical shape and is provided so as not to be displaced relative to the fixed side sleeve and slides relative to the movable side sleeve, and a concave cam portion that is cut out in a spiral shape along the axial direction on one of the sliding sleeve and the movable side sleeve, and a convex cam portion that is slidably fitted into the concave cam portion on the other of the sliding sleeve and the movable side sleeve , and the sliding sleeve is preferably provided on the drive plate. According to this, the centrifugal clutch can be expected to have the same effect as the pulley device. According to the feature of the present invention configured in this way, the centrifugal clutch has a sliding sleeve provided on the drive plate, and therefore the configuration of the fixed side driven plate can be simplified and reduced in weight.

1 is a plan cross-sectional view showing a schematic configuration of a power transmission mechanism including a pulley device and a centrifugal clutch according to a first embodiment of the present invention. 2 is an exploded perspective assembly view showing the outline of the external configuration of a fixed driven plate, a movable driven plate, and a sliding sleeve that constitute the pulley device shown in FIG. 1. 11 is a plan cross-sectional view showing a schematic configuration of a power transmission mechanism including a pulley device and a centrifugal clutch according to a second embodiment of the present invention. FIG. FIG. 4 is a perspective view showing the outline of the external configuration of a movable-side driven plate constituting the pulley device shown in FIG. 3 . 4 is a perspective view showing the outline of the external configuration of a sliding sleeve constituting the pulley device shown in FIG. 3, as viewed from the main body side. FIG. 4 is a perspective view showing the outline of the external configuration of a sliding sleeve constituting the pulley device shown in FIG. 3, as viewed from a plate fitting portion side. FIG.

First Embodiment
Hereinafter, an embodiment of a pulley device and a centrifugal clutch including the pulley device according to the present invention will be described with reference to the drawings. Fig. 1 is a plan sectional view showing a schematic configuration of a power transmission mechanism 100 including a pulley device 130 and a centrifugal clutch 200 according to a first embodiment of the present invention. In this case, Fig. 1 shows the upper half of the pulley device 130 and the centrifugal clutch 200 in a state where the movable driven plate 150 is closest to the fixed driven plate 140, and shows the lower half of the pulley device 130 and the centrifugal clutch 200 in a state where the movable driven plate 150 is farthest from the fixed driven plate 140.

The power transmission mechanism 100, which includes the pulley device 130 and the centrifugal clutch 200, is a mechanical device that is provided between the engine and the rear wheel, which is the driving wheel, mainly in motorcycles such as scooters, and transmits or cuts off the rotational driving force to the rear wheel while automatically changing the reduction ratio according to the engine speed. In this case, the centrifugal clutch 200 is a mechanical device that cuts off the transmission of the rotational driving force to the driven side until the engine reaches a predetermined speed, and transmits the rotational driving force to the driven side when the engine reaches the predetermined speed.

(Configuration of Pulley Device 130 and Centrifugal Clutch 200)
This power transmission mechanism 100 mainly includes a transmission 101 and a centrifugal clutch 200. The transmission 101 is a mechanical device that continuously reduces the rotational driving force from an engine (not shown) and transmits it to the centrifugal clutch 200, and is mainly configured with a drive pulley 110, a V-belt 120, and a pulley device 130. Of these, the drive pulley 110 is a mechanical device that is provided on a crankshaft 111 extending from the engine and is directly driven to rotate by the rotational driving force of the engine, and is mainly configured with a fixed drive plate 112 and a movable drive plate 113.

The fixed drive plate 112 is a part that rotates while holding the V-belt 120 together with the movable drive plate 113, and is made of a metal material formed into a conical cylindrical shape. This fixed drive plate 112 is fixedly attached to the crankshaft 111 with the convex surface facing the movable drive plate 113 side (engine side). In other words, the fixed drive plate 112 always rotates integrally with the crankshaft 111. In addition, multiple heat dissipation fins 112a are provided on the concave surface of the fixed drive plate 112 radially around the axis of the crankshaft 111.

The movable drive plate 113 is a component that rotates while being held together with the fixed drive plate 112 by sandwiching the V-belt 120, and is made of a metal material formed into a conical cylindrical shape. This movable drive plate 113 is attached to the crankshaft 111 with the convex surface facing the fixed drive plate 112. In this case, the movable drive plate 113 is attached via an impregnated bushing onto a sleeve bearing 114 that is fixedly fitted to the crankshaft 111, and is attached to the sleeve bearing 114 so that it can slide freely in both the axial and circumferential directions.

On the other hand, multiple roller weights 115 are provided on the concave surface of the movable drive plate 113 in a state where they are pressed by the ramp plate 116. The roller weights 115 are components that work together with the ramp plate 116 to press the movable drive plate 113 toward the fixed drive plate 112 by displacing radially outward as the rotation speed of the movable drive plate 113 increases, and are made of a metal material formed into a cylindrical shape. The ramp plate 116 is a component that presses the roller weights 115 toward the movable drive plate 113, and is made 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 drive pulley 110 to the driven pulley 131 of the pulley device 130, and is formed in an endless ring shape with a core wire covered with an elastic material such as rubber. The V-belt 120 is disposed between the fixed drive plate 112 and the movable drive plate 113 and between the fixed side driven plate 140 and the movable side driven plate 150 of the driven pulley 131, and is stretched between the drive pulley 110 and the driven pulley 131.

The pulley device 130 is a mechanical device that is rotated by the rotational driving force from the engine transmitted via the drive 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 part that rotates while holding the V-belt 120 together with the movable side driven plate 150, and is made of a metal material such as aluminum formed into a conical cylinder. This fixed side driven plate 140 is mainly made up of a fixed side plate 141 and a fixed side sleeve 142.

The fixed plate 141, which is a part that sandwiches the V-belt 120 together with the movable plate 151, is formed in a conical surface that protrudes toward the movable plate 151. A fixed sleeve 142 is formed in the center of this fixed plate 141.

The fixed side sleeve 142 is a part that rotates and drives together with the fixed side plate 141, and is formed in a cylindrical shape that extends in a direction perpendicular to the fixed side plate 141. The fixed side plate 141 is connected to one end of the fixed side sleeve 142 (the right side in the figure), and a cam forming protrusion 143 is formed in a part adjacent to this connection part. In addition, an externally toothed spline is formed in the other end of the fixed side sleeve 142 (the left side in the figure), and the drive plate 210 is connected via this spline by spline fitting.

The cam forming protrusion 143 is a portion for forming the concave cam portion 144 in the fixed sleeve 142, and is formed to protrude convexly from the outer surface of the fixed sleeve 142. Here, the concave cam portion 144 is a portion into which the convex cam portion 154 fits in a freely slidable state. In this embodiment, the cam forming protrusion 143 is formed in a spiral shape that extends in the axial direction while twisting in the circumferential direction of the fixed sleeve 142. In this case, three cam forming protrusions 143 are formed at equal intervals in the circumferential direction of the fixed sleeve 142.

As a result, one concave cam portion 144 is formed between two adjacent cam forming protrusions 143 on the outer periphery of the fixed sleeve 142. Therefore, three concave cam portions 144 are formed in the circumferential direction on the outer periphery of the fixed sleeve 142 via the cam forming protrusions 143. In this case, the three concave cam portions 144 are each formed in a groove shape that extends spirally in the axial direction of the fixed sleeve 142. In addition, the three concave cam portions 144 are formed with their bottoms protruding from the outer surface of the fixed sleeve 142. In other words, the outer diameter of the part of the fixed sleeve 142 where the cam forming protrusions 143 are formed is formed slightly thicker, thereby increasing the rigidity.

The fixed side driven plate 140 is formed integrally by integral molding of the fixed side sleeve 142 and the fixed side plate 141, which include the cam forming protrusion 143 and the concave cam portion 144, using the same material. The fixed side driven plate 140 may be formed integrally by molding the fixed side sleeve 142 and the fixed side plate 141, which include the cam forming protrusion 143 and the concave cam portion 144, as separate parts and connecting them to each other via welding or the like. The fixed side driven plate 140 may also be formed on the fixed side sleeve 142 by connecting the cam forming protrusion 143 to the fixed side sleeve 142 as a separate part.

A drive shaft 145 penetrates the fixed sleeve 142 of the fixed driven plate 140. The drive shaft 145 is a metallic rotating shaft for driving the rear wheel of the motorcycle on which the power transmission mechanism 100 is mounted via a transmission (not shown). In this case, the rear wheel of the motorcycle is attached to one end (not shown) of the drive shaft 145 (the right end in the figure). The drive shaft 145 supports the fixed driven plate 140 via bearings 146a and 146b. A male screw is formed at the tip of the drive shaft 145 on the left side in the figure, and the clutch outer 230 is attached via the male screw and a nut that threads onto the male screw. In FIG. 1, the drive shaft 145 is indicated by a two-dot chain line.

The bearings 146a and 146b are annular parts for supporting the fixed-side driven plate 140 on the drive shaft 145 in a state in which it can be rotated. In this case, the bearing 146a is provided at the most distal end (left end in the figure) where the drive shaft 145 supports the fixed-side sleeve 142. The bearing 146b is provided at the most distal end (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 overlapping the radial inner side of the cam forming protrusion 143 and the concave cam portion 144. The bearing 146b may be configured with the same load capacity as the bearing 146a, but in this embodiment, the axial length of the bearing 146b is longer than that of the bearing 146a, and the load capacity is greater.

The movable driven plate 150 is a part that rotates while holding the V-belt 120 together with the fixed driven plate 140, and is made of a metal material such as aluminum formed into a conical cylinder. This movable driven plate 150 is mainly made up of a movable plate 151 and a movable sleeve 152.

The movable plate 151, which is a part that sandwiches the V-belt 120 together with the fixed plate 141, is formed in a conical surface that protrudes toward the fixed plate 141. A movable sleeve 152 is formed in the center of the movable plate 151.

The movable sleeve 152 is a part that rotates integrally with the movable plate 151, and is formed in a cylindrical shape that extends in a direction perpendicular to the movable plate 151. In this case, the movable sleeve 152 is formed with an inner diameter that allows the fixed sleeve 142 to pass through. The movable sleeve 152 has one end (the right side in the figure) to which the movable plate 151 is connected, and a cam connection part 152a is formed at the other end (the left side in the figure).

The cam connecting portion 152a is a portion for connecting the sliding sleeve 153, and is formed by cutting out a portion of the end of the movable sleeve 152 in a concave shape in the axial direction. In this embodiment, the cam connecting portion 152a is formed by cutting out three concave cutouts evenly spaced along the circumferential direction on the end of the movable sleeve 152.

2, the sliding sleeve 153 is disposed between the fixed sleeve 142 and the movable sleeve 152 to slide the movable sleeve 152 relative to the fixed sleeve 142 and is a part for forming the convex cam portion 154 that meshes with the concave cam portion 144, and is configured by forming a resin material into a cylindrical shape. The cylindrical body that constitutes this sliding sleeve 153 is formed with an outer diameter that slidably fits with the inner peripheral surface 152b of the movable sleeve 152, and is formed with an inner diameter that slidably fits with the outer peripheral surface of the fixed sleeve 142. Moreover, the sliding sleeve 153 has a sleeve connecting portion 153a formed at one end of the cylindrical body, and a convex cam portion 154 formed at the other end.

The sleeve connecting portion 153a is a portion that fits into 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 protruding portions evenly arranged along the circumferential direction at the end of the sliding sleeve 153 so that the three protruding portions fit into the three cam connecting portions 152a, respectively.

The convex cam portion 154 is a portion that protrudes from the inner peripheral surface 152b of the movable sleeve 152 and slidably fits into the concave cam portion 144 formed in the fixed sleeve 142, and is formed to protrude spirally in the axial direction at the end of the sliding sleeve 153. In this case, the convex cam portion 154 may be configured to contact the outer peripheral surface of the fixed sleeve 142, but in this embodiment, it is formed to extend in a non-contact state. Three of these convex cam portions 154 are formed at the end of the sliding sleeve 153 at equal intervals in the circumferential direction so as to correspond to the concave cam portions 144.

That is, between each of the three convex cam portions 154, a cam forming notch 153b for forming each convex cam portion 154 is formed extending in a spiral shape. The cam forming protrusion 143 formed on the fixed sleeve 142 is slidably fitted into these three cam forming notches 153b. Therefore, the cam forming protrusion 143 formed on the fixed sleeve 142 can be considered as the convex cam portion according to the present invention formed on the fixed sleeve 142, and the cam forming notch 153b formed on the sliding sleeve 153 (movable sleeve 152) can be considered as the concave cam portion according to the present invention formed on the sliding sleeve 153 (movable sleeve 152).

This sliding sleeve 153 is fixedly fitted into the movable sleeve 152 of the movable driven plate 150 via adhesive or the like with the sleeve connecting portion 153a fitted into the cam connecting portion 152a. As a result, the sliding sleeve 153 rotates integrally with the movable sleeve 152 with the convex cam portion 154 fitted into the concave cam portion 144 formed on the fixed sleeve 142.

The resin material constituting the sliding sleeve 153 may be a thermoplastic resin or a thermosetting resin having heat resistance and abrasion resistance, and engineering plastics or super engineering plastics are preferable. Specifically, the thermoplastic resin may be polyether ether ketone resin (PEEK), polyphenylene sulfide resin (PPS), polyamide imide resin (PAI), fluororesin (PTFE), or polyimide resin (PI), and the thermosetting resin may be diallyl phthalate resin (PDAP), epoxy resin (EP), or silicone resin (SI).

On the other hand, a torque spring 155 is provided between the drive plate 210 of the centrifugal clutch 200 and the concave surface of the movable driven plate 150. The torque spring 155 is a coil spring for elastically pressing the movable driven plate 150 toward the fixed driven plate 140. In other words, this transmission 101 changes the engine speed steplessly depending on the relationship between the diameter of the V-belt 120, which is determined by the distance between the fixed drive plate 112 and the movable drive plate 113, and the diameter of the V-belt 120, which is determined by the distance between the fixed driven plate 140 and the movable driven plate 150. A centrifugal clutch 200 is provided on each tip side of the fixed sleeve 142 and the drive shaft 145.

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

The drive plate 210 is a part that rotates and drives together with the fixed sleeve 142, and is configured by forming a stepped disk out of a metal material. More specifically, the drive plate 210 is configured such that an internal spline is formed in the center of a flat bottom 211, into which the external spline of the fixed sleeve 142 penetrates and engages, and a flange-like flange 212 is formed that projects radially outward through a stepped portion that stands up around the periphery of the bottom 211.

The drive plate 210 has the torque spring 155 provided on the inside of the step at the outer edge of the bottom 211. The flange 212 also has three swing support pins 213 and three weight pressing body support parts 215 provided at equal intervals along the circumferential direction.

The swing support pin 213 is a part for rotatably supporting one end of the clutch weight 220 described below and swinging the other end, and is composed of a stepped metal rod. In this case, the swing support pin 213 is fixedly attached to the flange 212 by a mounting bolt 213a. The swing support pin 213 passes through the pin slide hole 222 of the clutch weight 220 and supports the clutch weight 220 by sandwiching it between the swing support pin 213 and the side plate 214 attached to the tip of the swing support pin 213.

The side plate 214 is a component that prevents the three clutch weights 220 from coming off the swing support pins 213, and is made of a metal material formed into a ring shape. This side plate 214 is positioned on the opposite side of the drive plate 210 from the three clutch weights 220, facing each of the clutch weights 220.

The weight pressing body support part 215 is a part for supporting the weight pressing body 216 in a rotatable state, and is composed of a stepped metal rod. The weight pressing body support part 215 is formed in a pin-like protrusion on the flange part 212 that faces the part of the clutch weight 220 closer to the tip end side than the pin sliding hole 222 in the clutch weight 220. The weight pressing body 216 is a part for pressing the clutch weight 220 towards the clutch outer 230, and is composed of a resin material formed into a cylindrical shape.

The three clutch weights 220 are components that transmit or block the rotational driving force from the engine to the drive shaft 145 by contacting or separating from the clutch outer 230 via the clutch shoe 221 depending on the rotation speed of the drive plate 210, and are made of a metal material (e.g., zinc) formed into a curved shape that extends circumferentially around the drive plate 210.

The clutch shoe 221 is a part for increasing the frictional force against the inner peripheral surface of the clutch outer 230, and is configured by forming a friction material into a plate shape extending in an arc. This clutch shoe 221 is attached to the outer peripheral surface of the tip end side of each clutch weight 220, which is the other end side of the clutch weight 220.

Each of these clutch weights 220 has a pin slide hole 222 formed as a long through hole on one end side, and is supported rotatably by the swing support pin 213 via the pin slide hole 222. The other end side of each clutch weight 220 is connected to the adjacent clutch weight 220 by a connecting spring 223 and pulled toward the inside of the drive plate 210. In other words, the clutch weights 220 are supported on the drive plate 210 via the swing support pin 213 and the pin slide hole 222 so that the other end side where the clutch shoe 221 is provided swings relative to the clutch outer 230.

The connecting spring 223 is a component that applies a tensile force to the clutch weight 220 to pull the other end side in a direction away from the clutch outer 230, and is made of a metal coil spring. The connecting spring 223 is installed between adjacent clutch weights 220 along the circumferential direction of the drive plate 210.

In addition, a pressing body accommodating portion 224 is formed on the inner surface of each clutch weight 220 facing the drive plate 210. The pressing body accommodating portion 224 is a portion that accommodates the weight pressing body 216 and forms a pressing body receiving portion 224a against which the weight pressing body 216 is pressed, and is formed by cutting out a concave shape on the inner surface of the clutch weight 220.

The pressing body receiving portion 224a is a portion for displacing the clutch weight 220 toward the clutch outer 230 by pressing the weight pressing body 216 against it. The pressing body receiving portion 224a is configured with a smooth curved surface whose side surface within the pressing body housing portion 224 curves and extends toward the rear and outside in the rotational drive direction of the drive plate 210.

The clutch outer 230 is a part that rotates and drives together with the drive shaft 145, and is configured by forming a metal material into a cup shape that covers the outer circumferential surface of the clutch weight 220 from the drive plate 210. In other words, the clutch outer 230 is configured with a cylindrical surface 231 that comes into frictional contact with the clutch shoe 221 of the clutch weight 220 that is displaced toward the outer circumferential side of the drive plate 210.

(Operation of Pulley Device 130 and Centrifugal Clutch 200)
Next, the operation of the pulley device 130 and centrifugal clutch 200 configured as described above will be described. The centrifugal clutch 200 functions as part of a power transmission mechanism 100 disposed between an engine and a rear wheel serving as a driving wheel in a motorcycle (e.g., a scooter). First, when the engine is idling, the centrifugal clutch 200 cuts off the transmission of driving force between the engine and the drive shaft 145, as shown in FIG. 1.

Specifically, in the pulley device 130, the driven pulley 131 is rotated by the rotational driving force of the engine transmitted via the drive 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 via a sliding sleeve 153, and the fixed side driven plate 140 is directly connected to the drive plate 210. As a result, the drive plate 210 is rotated at the same rotation speed as the fixed side driven plate 140 and the movable side driven plate 150. In other words, the three clutch weights 220 provided on the drive plate 210 in the centrifugal clutch 200 are rotated at the same rotation speed as the drive plate 210.

However, in this case, the centrifugal clutch 200 does not tilt toward the cylindrical surface 231 of the clutch outer 230 so that the clutch shoe 221 comes into contact with the cylindrical surface 231 of the clutch outer 230, because the centrifugal force acting on the clutch weight 220 is smaller than the elastic force (tensile force) of the connecting spring 223. Therefore, the centrifugal clutch 200 is in a clutch-off state without the rotational driving force of the engine being transmitted to the drive shaft 145.

In this clutch-off state, the driven pulley 131 is elastically pressed by the torque spring 155 at the position closest to or near the fixed driven plate 140. Therefore, the movable driven plate 150 transmits the rotational drive force to the fixed driven plate 140 with the convex cam portion 154 of the sliding sleeve 153 deeply fitted into the concave cam portion 144 formed in the fixed sleeve 142 of the fixed driven plate 140. In other words, the movable driven plate 150 transmits the rotational drive force with the contact area between the convex cam portion 154 and the concave cam portion 144 at or near the maximum, so that the rotational drive force can be stably transmitted to the fixed driven plate 140 at low revolutions when the engine speed tends to be unstable, such as when idling.

Next, the centrifugal clutch 200 transmits the rotational driving force of the engine to the drive shaft 145 in response to an increase in engine speed caused by the driver's operation of the accelerator in the motorcycle. Specifically, as the engine speed increases, the centrifugal force acting on the clutch weight 220 becomes greater than the elastic force (tensile force) of the connecting spring 223, causing the clutch weight 220 to rotate radially outward around the swing support pin 213.

In other words, as the engine speed increases, the centrifugal clutch 200 rotates and displaces the clutch weight 220 toward the cylindrical surface 231 of the clutch outer 230 while resisting the elastic force (tensile force) of the connecting spring 223, causing the clutch shoe 221 to come into contact with the cylindrical surface 231.

As a result, the clutch weight 220 receives a reaction force in the opposite direction to the rotational drive direction via the clutch shoe 221, and is displaced relative to the drive plate 210 in the opposite direction to the rotational drive direction. In this case, the clutch weight 220 is pushed radially outward toward the clutch outer 230 as the pressure body receiving portion 224a rides up onto the weight pressure body 216 while rotating and displacing the weight pressure body 216, and the clutch shoe 221 is pressed strongly against the cylindrical surface 231.

In other words, after the clutch shoe 221 comes into contact with the cylindrical surface 231 of the clutch outer 230, the clutch shoe 221 is pressed against the cylindrical surface 231 in an extremely short time (in other words, instantaneously) and the clutch weight 220 is wedged between the weight pressing body 216 and the clutch outer 230. This puts the centrifugal clutch 200 in a clutch-on state in which the rotational driving force of the engine is completely transmitted to the drive shaft 145. Therefore, the motorcycle can run with the rear wheel being rotated by the rotational driving force of the engine.

In the process of transitioning to this clutch-on state, the driven pulley 131 displaces the movable driven plate 150 away from the fixed driven plate 140 against the elastic force of the torque spring 155 as the engine speed increases. In this case, the movable driven plate 150 moves away from the fixed driven plate 140 as the sliding sleeve 153 attached to the movable sleeve 152 slides on the fixed sleeve 142 to the left in the figure.

Therefore, the convex cam portion 154 formed on the sliding sleeve 153 slides and displaces to the left side in the figure relative to the concave cam portion 144 formed on the fixed side driven plate 140. As a result, the cam forming protrusion 143 and the concave cam portion 144 formed on the fixed side driven plate 140 are exposed to the V-belt 120 side with a reduced amount of engagement with the cam forming notch portion 153b and the convex cam portion 154. In other words, the movable side driven plate 150 transmits the rotational driving force to the fixed side driven plate 140 with the contact area between the convex cam portion 154 and the concave cam portion 144 being minimum or close to minimum.

On the other hand, when the engine speed decreases, the centrifugal clutch 200 cuts off the transmission of the rotational driving force of the engine to the drive shaft 145. Specifically, as the engine speed decreases, the centrifugal force acting on the clutch weight 220 becomes smaller than the elastic force (tensile force) of the connecting spring 223, and the clutch weight 220 rotates radially inward around the swing support pin 213.

As a result, the clutch weight 220 returns to its original position (the position during idling) with the clutch shoe 221 moving away from the cylindrical surface 231 of the clutch outer 230. In other words, the centrifugal clutch 200 is in a clutch-off state in which the clutch shoe 221 is not in contact with the clutch outer 230 and does not transmit rotational driving force.

In this case, the driven pulley 131 is displaced such that the movable driven plate 150 approaches the fixed driven plate 140 due to the elastic force of the torque spring 155 as the engine speed decreases. In this case, the sliding sleeve 153 attached to the movable sleeve 152 slides on the fixed sleeve 142 to the right in the figure, causing the movable driven plate 150 to approach the fixed driven plate 140. As a result, the concave cam portion 144 formed on the fixed driven plate 140 increases the amount of engagement with the convex cam portion 154 formed on the movable driven plate 150 as the convex cam portion 154 slides and displaces to the right in the figure, thereby decreasing the amount of exposure.

As can be understood from the above description of operation, according to the first embodiment, the pulley device 130 has a cylindrical sliding sleeve 153 that displaces integrally with the movable sleeve 152 relative to the fixed sleeve 142, and a convex cam portion 154 that meshes with the concave cam portion 144 formed on the fixed sleeve 142 is formed on the sliding sleeve 153, and the sliding sleeve 153 slides and displaces directly relative to the fixed sleeve 142. As a result, according to the pulley device 130 of the present invention, the sliding sleeve 153 can be displaced more smoothly than when the sliding sleeve 153 is displaced via the movable sleeve 152. In addition, according to the pulley device 130 of the present invention, the convex cam portion 154 is formed on the sliding sleeve 153, thereby reducing the number of parts, making it possible to reduce the size and weight of the pulley device 130 and the centrifugal clutch 200 and reduce the manufacturing burden.

Furthermore, the implementation of the present invention is not limited to the first embodiment described above, and various modifications are possible without departing from the purpose of the present invention.

For example, in the first embodiment, the pulley device 130 is configured by forming the concave cam portion 144 on the fixed sleeve 142 of the fixed driven plate 140 and forming the convex cam portion 154 protruding radially inward on the sliding sleeve 153. However, the pulley device 130 can also be configured by forming the convex cam portion 154 protruding radially outward on the fixed sleeve 142 of the fixed driven plate 140 and forming the concave cam portion 144 on the sliding sleeve 153. In this case, the pulley device 130 forms the groove-shaped or through-hole-shaped cam forming notch portion 153b on the fixed sleeve 142 of the fixed driven plate 140 and forms the cam forming protrusion portion 143 on the sliding sleeve 153.

That is, the concave cam portion 144 can be formed by cutting out a through hole or groove extending in a spiral shape into one of the fixed sleeve 142 and the sliding sleeve 153. In this case, the convex cam portion 154 can be formed to protrude radially into the other of the fixed sleeve 142 and the sliding sleeve 153 and to slidably fit within the concave cam portion 144.

In the first embodiment, the concave cam portion 144 is formed as a groove with a bottom. However, the concave cam portion 144 can also be formed as a through hole that penetrates the fixed sleeve 142 and extends spirally in the axial direction of the fixed sleeve 142. In this way, the pulley device 130 has the through-hole-shaped concave cam portion 144 formed in the fixed sleeve 142, so that the ventilation to the inside of the fixed sleeve 142 is ensured, improving heat dissipation and durability. The concave cam portion 144 can also be formed as a through hole when formed in the sliding sleeve 153.

In the first embodiment, the concave cam portion 144 is formed by a cam forming protrusion 143 formed on the outer peripheral surface of the fixed sleeve 142. This allows the concave cam portion 144 to function as a rib that increases the thickness of the fixed sleeve 142, improving rigidity and durability. However, the concave cam portion 144 can also be formed as a groove or through hole that is recessed concavely from the surface of the outer peripheral surface of the fixed sleeve 142.

In the first embodiment, the convex cam portion 154 is formed to protrude in a spiral shape in the axial direction from the end of the sliding sleeve 153. As a result, the convex cam portion 154 is formed to protrude in a rail-like shape from the inner peripheral surface 152b of the movable sleeve 152. However, it is sufficient that the convex cam portion 154 is configured to protrude in a convex shape from the inner peripheral surface 152b of the movable sleeve 152 and to slidably fit into the concave cam portion 144. Therefore, the convex cam portion 154 can also be formed in a pin shape configured in a rod state, for example.

In the first embodiment, the sliding sleeve 153 is made of a resin material and the fixed sleeve 142 is made of a metal material. That is, the pulley device 130 has the sliding sleeve 153 and the fixed sleeve 142 made of different materials. This allows the pulley device 130 to improve the sliding properties between the sliding sleeve 153 and the fixed sleeve 142 and between the concave cam portion 144 and the convex cam portion 154 and to suppress wear and deterioration. However, the pulley device 130 can also have the sliding sleeve 153 and the fixed sleeve 142 made of the same material. The pulley device 130 can also have the sliding sleeve 153 and the fixed sleeve 142 made of a material other than a resin material and a metal material, for example, a ceramic material.

Second Embodiment
Next, a second embodiment of the pulley device and the centrifugal clutch including the pulley device according to the present invention will be described with reference to Fig. 3 to Fig. 6. In the first embodiment, the sliding sleeve 153 in the pulley device 130 is formed in a cylindrical shape provided between the fixed sleeve 142 and the movable sleeve 152, displaces integrally with the movable sleeve 152, and slides relative to the fixed sleeve 142. On the other hand, the sliding sleeve 160 in the pulley device 130 in the second embodiment is formed in a cylindrical shape provided between the fixed sleeve 142 and the movable sleeve 152, is not displaceable relative to the fixed sleeve 142, and slides relative to the movable sleeve 152, which is different from the first embodiment.

Therefore, the pulley device 130 and centrifugal clutch 200 in this second embodiment will be described focusing on the parts that are different from the pulley device 130 and centrifugal clutch 200 in the first embodiment, and the parts that are common to both embodiments and corresponding parts will be omitted as appropriate. Note that in FIG. 3, the configuration on the drive pulley 110 side of the transmission 101 is omitted. Also, in FIG. 3, as in FIG. 1 in the first embodiment, the upper half of the pulley device 130 and centrifugal clutch 200 shows the state in which the movable side driven plate 150 is closest to the fixed side driven plate 140, and the lower half of the pulley device 130 and centrifugal clutch 200 shows the state in which the movable side driven plate 150 is farthest from the fixed side driven plate 140.

(Configuration of Pulley Device 130 and Centrifugal Clutch 200)
The pulley device 130 is configured with a driven pulley 131 including a fixed side driven plate 140 and a movable side driven plate 150, similar to the pulley device 130 in the first embodiment.

The fixed-side driven plate 140 is configured with a fixed-side plate 141 and a fixed-side sleeve 142 similar to the fixed-side plate 141 and the fixed-side sleeve 142 in the first embodiment. In this case, the fixed-side sleeve 142 differs from the first embodiment in that the cam forming protrusion 143 and the concave cam portion 144 in the first embodiment are not formed.

As shown in FIG. 4, the movable driven plate 150 is configured with a movable plate 151 and a movable sleeve 152 similar to the movable plate 151 and the movable sleeve 152 in the first embodiment. In this case, the movable sleeve 152 has a concave cam portion 156 formed at the end on the drive plate 210 side instead of the cam connection portion 152a in the first embodiment.

The concave cam portion 156 is a portion into which a convex cam portion 165 formed on the sliding sleeve 160 described later is slidably fitted, and is formed in a spiral shape extending in the axial direction while twisting in the circumferential direction at the left end portion of the movable sleeve 152 in the drawing. In this case, the concave cam portion 156 is formed by cutting out the concave cam portion 156 so as to penetrate in the radial direction. Three concave cam portions 156 are formed at equal intervals in the circumferential direction of the movable sleeve 152.

That is, the concave cam portion 156 is formed between each of the three concave cam forming portions 157 that remain uncut at the end of the movable sleeve 152. Each of these concave cam portions 156 is formed to have a wall thickness thinner than the annular gap S of the outer cylindrical portion 162 formed in the sliding sleeve 160, and is formed so as not to contact each of the radially inner and outer side walls of the outer cylindrical portion. The concave cam portion 156 can be formed as a bottomed groove on the outer periphery of the movable sleeve 152 instead of a through hole. At least one concave cam portion 156 needs to be formed for the sliding sleeve 160. The concave cam portion 156 can also be formed so as to contact each of the radially inner and outer side walls of the outer cylindrical portion.

As shown in Figs. 5 and 6, the sliding sleeve 160 is a part that is disposed between the fixed sleeve 142 and the movable sleeve 152 to slide the movable sleeve 152 relative to the fixed sleeve 142 and to form a convex cam portion that engages with the concave cam portion 156, and is made of a resin material formed into a cylindrical shape. In this case, the sliding sleeve 160 can be made of the same resin material as the sliding sleeve 153 in the above embodiment. This sliding sleeve 160 is mainly made up of a main body portion 161 and an outer cylindrical portion 162.

The main body 161 is formed in a cylindrical shape and is fitted onto the outer periphery of the fixed sleeve 142 of the fixed driven plate 140 in a state where it cannot be displaced relative to the fixed sleeve 142, and into which the movable sleeve 152 of the movable driven plate 150 is fitted in a state where it can slide freely. The outer tube 162 is the part where the convex cam portion 165 is formed, and is formed in a cylindrical shape that covers the end of the main body 161 on the drive plate 210 side via a gap S.

In this case, the ring-shaped gap S formed inside the outer cylinder portion 162 is where the convex cam portion 165 is formed and where the concave cam portion 156 and the concave cam forming portion 157 are inserted. The outer periphery of the outer cylinder portion 162 has a spring receiving portion 163 and a plate fitting portion 164 formed at the end on the drive plate 210 side. The portion of the outer cylinder portion 162 closer to the movable plate 151 than the spring receiving portion 163 covers the outside of the concave cam forming portion 157 to prevent contact with the torque spring 155.

The spring receiving portion 163 is a portion that receives the end of the torque spring 155 on the drive plate 210 side, and is formed by projecting radially outward from the outer periphery of the outer cylindrical portion 162 in a flange-like shape. The plate fitting portion 164 is a portion that fits into a sleeve fitting hole 217 formed in the drive plate 210 to rotate the sliding sleeve 160 integrally with the drive plate 210, and is formed in a state where it protrudes from the end of the main body portion 161 and the end face of the spring receiving portion 163.

In this embodiment, three plate fitting portions 164 are formed at equal intervals along the circumferential direction of the spring receiving portion 163. That is, the sliding sleeve 160 rotates integrally with the drive plate 210 and the fixed side driven plate 140 by fitting the plate fitting portions 164 into the sleeve fitting holes 217 formed in the drive plate 210. In addition, a through hole is formed in the plate fitting portion 164 so that the concave cam forming portion 157 formed in the movable side sleeve 152 can pass through.

The convex cam portion 165 is a portion with which the concave cam portion 156 formed on the movable sleeve 152 slidably meshes and fits, and is formed in a state where it protrudes into the space between the main body portion 161 and the outer cylindrical portion 162 of the sliding sleeve 160. In this case, the convex cam portion 165 is formed extending spirally in the axial direction of the sliding sleeve 160. Three convex cam portions 165 are formed at equal intervals in the circumferential direction of the sliding sleeve 160.

That is, between each of the three convex cam portions 165, a cam forming notch 166 for forming each convex cam portion 165 is formed extending in a spiral shape. The three cam forming notches 166 are slidably fitted with the concave cam forming portion 157 formed on the movable sleeve 152. Therefore, the concave cam forming portion 157 formed on the movable sleeve 152 can be regarded as the convex cam portion according to the present invention formed on the sliding sleeve 160, and the cam forming notch 166 formed on the sliding sleeve 160 can be regarded as the concave cam portion according to the present invention formed on the sliding sleeve 160. In addition, these cam forming notches 166 may be configured to contact the outer periphery of the main body portion 161 and the inner periphery of the outer tubular portion 162 of the sliding sleeve 160, but in this embodiment, they are configured to be non-contact with the outer periphery of the main body portion 161 and the inner periphery of the outer tubular portion 162.

The drive plate 210 has sleeve fitting holes 217 formed on the outside of the internally toothed splines in the bottom portion 211 into which the fixed sleeve 142 fits. The sleeve fitting holes 217 are through holes into which the three plate fitting portions 164 of the sliding sleeve 160 respectively fit, and three are formed at equal intervals around the circumference of the drive plate 210.

(Operation of Pulley Device 130 and Centrifugal Clutch 200)
Next, the operation of the pulley device 130 and centrifugal clutch 200 configured as above will be described.

First, when the centrifugal clutch 200 is in the clutch-off state, the driven pulley 131 has the movable driven plate 150 elastically pressed by the torque spring 155 at a position closest to or in the vicinity of the fixed driven plate 140. In this case, the movable sleeve 152 slides on the main body 161 of the sliding sleeve 160, and the movable driven plate 150 is elastically pressed toward the fixed driven plate 140. Therefore, the movable driven plate 150 transmits the rotational driving force to the drive plate 210 in a state in which the convex cam portion 165 formed on the sliding sleeve 160 is engaged with the concave cam portion 156 with a minimum or near-minimum contact area.

Next, when the centrifugal clutch 200 transitions to the clutch-on state, the driven pulley 131 displaces the movable driven plate 150 away from the fixed driven plate 140 against the elastic force of the torque spring 155 as the engine speed increases. In this case, the movable driven plate 150 moves away from the fixed driven plate 140 as the movable sleeve 152 slides on the sliding sleeve 160 to the left in the figure.

Therefore, the concave cam portion 156 and the concave cam forming portion 157 formed on the movable sleeve 152 penetrate deeply into the sliding sleeve 160. As a result, the movable driven plate 150 transmits the rotational driving force to the drive plate 210 with the contact area between the convex cam portion 165 and the concave cam portion 156 at or near the maximum.

On the other hand, when the engine speed decreases, the driven pulley 131 displaces the movable driven plate 150 closer to the fixed driven plate 140 due to the elastic force of the torque spring 155 as the engine speed decreases. In this case, the movable driven plate 150 approaches the fixed driven plate 140 as the movable sleeve 152 slides on the sliding sleeve 160 to the right in the figure. As a result, the convex cam portion 165 formed on the sliding sleeve 160 transmits the rotational driving force of the movable driven plate 150 to the drive plate 210 in a state where the amount of engagement with the concave cam portion 156 formed on the movable driven plate 150 is reduced as the concave cam portion 156 slides and displaces to the right in the figure.

As can be understood from the above description of operation, according to the second embodiment, the pulley device 130 has a cylindrical sliding sleeve 160 that is provided so as not to be rotatably displaced relative to the fixed sleeve 142, and a convex cam portion 165 that meshes with a concave cam portion 156 formed on the movable sleeve 152 is formed on the cylindrical sliding sleeve 160, and the movable sleeve 152 slides and displaces directly on the sliding sleeve 160. As a result, according to the pulley device 130 of the present invention, the cam mechanism consisting of the convex cam portion 165 and the concave cam portion 156 can be smoothly operated. In addition, according to the pulley device 130 of the present invention, the convex cam portion 165 is formed on the sliding sleeve 160, thereby reducing the number of parts, making the pulley device 130 smaller, lighter, and less burdensome to manufacture.

Furthermore, the implementation of the present invention is not limited to the second embodiment described above, and various modifications are possible without departing from the purpose of the present invention.

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

That is, the concave cam portion 156 can be formed by cutting out a through-hole or groove extending spirally in one of the movable sleeve 152 and the sliding sleeve 160. In this case, the convex cam portion 165 can be formed to protrude radially into the other of the movable sleeve 152 and the sliding sleeve 160 and to slidably fit within the concave cam portion 156.

In the second embodiment, the concave cam portion 156 is formed by cutting out the movable sleeve 152 so as to penetrate it. However, the concave cam portion 156 can also be formed as a groove with a bottom on the outer peripheral surface or a top on the inner peripheral surface of the movable sleeve 152 that does not penetrate it. In this case, the convex cam portion 165 can be formed with an amount of protrusion that does not reach the main body portion 161 from the inner peripheral surface of the outer cylindrical portion 162 of the sliding sleeve 160, or with an amount of protrusion that does not reach the inner peripheral surface of the outer cylindrical portion 162 from the outer peripheral surface of the main body portion 161.

The concave cam portion 156 can also be formed at a position that protrudes from the outer circumferential surface of the movable sleeve 152, like the concave cam portion 144 in the first embodiment. In other words, the concave cam portion 156 can be formed by forming at least two cam forming protrusions 143 in the first embodiment on the outer circumferential surface of the movable sleeve 152, and then forming a concave cam portion 156 similar to the concave cam portion 144 between these two cam forming protrusions 143.

In the second embodiment, the convex cam portion 165 is formed in a spiral shape in a state where it is bridged between the main body portion 161 and the outer cylindrical portion 162 of the sliding sleeve 160. However, it is sufficient that the convex cam portion 165 is configured so as to be slidably fitted into the concave cam portion 156. Therefore, the convex cam portion 165 can also be formed in a pin shape configured in a rod state, for example.

In the second embodiment, the sliding sleeve 160 is configured with an outer tubular portion 162 on the outside of the main body portion 161. This allows the sliding sleeve 160 to 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 also prevents the torque 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 without the outer tubular portion 162.

In the second embodiment, the sliding sleeve 160 is connected to the sleeve fitting hole 217 of the drive plate 210. However, the sliding sleeve 160 only needs to be configured to rotate integrally with the fixed side driven plate 140 and the drive plate 210. Therefore, the sliding sleeve 160 may be attached to the fixed side sleeve 142 of the fixed side driven plate 140, for example.

In the second embodiment, the sliding sleeve 160 is made of a resin material and the movable sleeve 152 is made of a metal material. That is, the pulley device 130 has the sliding sleeve 160 and the movable sleeve 152 made of different materials. This allows the pulley device 130 to improve the sliding properties between the sliding sleeve 160 and the movable sleeve 152 and between the concave cam portion 156 and the convex cam portion 165 and to suppress wear and deterioration. However, the pulley device 130 can also have the sliding sleeve 160 and the movable sleeve 152 made of the same material. The pulley device 130 can also have the sliding sleeve 160 and the movable sleeve 152 made of a material other than a resin material and a metal material, for example, a ceramic material.

In addition, in each of the above embodiments, the pulley device 130 is configured with three concave cam portions 144, 156 and three convex cam portions 154, 165. However, the pulley device 130 may be configured with at least one set each of the concave cam portions 144, 156 and the convex cam portions 154, 165.

In the above embodiment, the centrifugal clutch 200 is configured to include the weight pressing body 216, the pressing body housing portion 224, and the pressing body receiving portion 224a. However, the centrifugal clutch 200 can also be configured to omit the weight pressing body 216, the pressing body housing portion 224, and the pressing body receiving portion 224a. Also, the centrifugal clutch 200 has the pin sliding hole 222 formed in an elongated hole shape in a plan view. However, the centrifugal clutch 200 can also have the pin sliding hole 222 formed in a circular shape in a plan view.

In the above embodiment, the pulley device 130 is applied to the centrifugal clutch 200. However, the pulley device 130 can be widely applied to mechanical devices that transmit driving force from a driving source such as an engine or an electric motor to an output shaft such as the drive shaft 145. Therefore, the pulley device 130 can also be applied to a multi-plate clutch that transmits or cuts off a rotational driving force by pressing two opposing plates, specifically, a plurality of friction plates with a friction material on the surface of a flat annular core metal and a plurality of clutch plates without friction material, against each other. The pulley device 130 can also be provided as part of a driving force transmission mechanism between an electric motor and driving wheels in an electric vehicle that runs on its own using an electric motor as a driving source.

S: a ring-shaped gap formed between the main body and the outer cylindrical portion of the sliding sleeve;
100...power transmission mechanism, 101...transmission,
110: drive pulley, 111: crankshaft, 112: fixed drive plate, 112a: heat dissipation fin, 113: movable drive plate, 114: sleeve bearing, 115: roller weight, 116: ramp plate,
120...V-belt,
130...pulley device, 131...driven pulley,
140: fixed side driven plate, 141: fixed side plate, 142: fixed side sleeve, 143: cam forming protrusion, 144: concave cam portion, 145: drive shaft, 146a, 146b: bearings,
150... Movable side driven plate, 151... Movable side plate, 152... Movable side sleeve, 152a... Cam connecting portion, 152b... Inner peripheral surface, 153... Sliding sleeve, 153a... Sleeve connecting portion, 153b... Cam forming notch portion, 154... Convex cam portion, 155... Torque spring, 156... Concave cam portion, 157... Concave cam forming portion,
160: sliding sleeve, 161: main body, 162: outer cylindrical portion, 163: spring receiving portion, 164: plate fitting portion, 165: convex cam portion, 166: cam forming notch portion,
200...Centrifugal clutch,
210: drive plate, 211: bottom, 212: flange, 213: swing support pin, 213a: mounting bolt, 214: side plate, 215: weight pressing body support portion, 216: weight pressing body, 217: sleeve fitting hole,
220: clutch weight; 221: clutch shoe; 222: pin slide hole; 223: connecting spring; 224: pressing body accommodating portion; 224a: pressing body receiving portion;
230: clutch outer; 231: cylindrical surface.

Claims (9)

a fixed-side driven plate having a flange-like protrusion on an outer circumferential surface of a cylindrical fixed-side sleeve, the fixed-side driven plate receiving a driving force from a driving source via a belt to rotate;
a movable-side driven plate having a movable-side plate that projects radially outward like a flange on an outer circumferential surface of a cylindrical movable-side sleeve and sandwiches the belt together with the fixed-side plate, the movable-side driven plate receiving a driving force from the driving source via the belt while approaching or moving away from the fixed-side plate and being driven to rotate;
a sliding sleeve formed in a cylindrical shape and provided between the fixed sleeve and the movable sleeve, the sliding sleeve displacing integrally with the movable sleeve and sliding relatively on an outer circumferential surface of the fixed sleeve;
a concave cam portion formed by cutting out a spiral shape along an axial direction in one of the sliding sleeve and the fixed sleeve;
a convex cam portion slidably fitted into the concave cam portion on the other of the sliding sleeve and the fixed sleeve,
The concave cam portion or the convex cam portion formed on the sliding sleeve is
a first end of said sliding sleeve having a cylindrical portion that slides relatively on the outer circumferential surface of said fixed sleeve, said first end being formed so as to extend in the axial direction. 2. The pulley device according to claim 1,
The concave cam portion or the convex cam portion formed on the sliding sleeve is
A pulley device characterized in that the fixed sleeve is not in contact with the main body. In the pulley device according to claim 1 or 2,
The movable sleeve is
A cam connection portion formed in a concave or convex shape is formed,
The sliding sleeve is
A pulley device, characterized in that a convex or concave sleeve connection portion is formed to fit into the cam connection portion. In the pulley device according to any one of claims 1 to 3,
A pulley device, wherein the sliding sleeve and the fixed sleeve are made of different materials. A pulley device according to any one of claims 1 to 4,
a drive plate connected to the fixed sleeve and rotated integrally with the fixed driven plate;
a clutch outer having a cylindrical surface provided concentrically with the drive plate on the outside of the drive plate and connected to a drive shaft;
a clutch weight having a clutch shoe formed extending along the circumferential direction of the drive plate and facing the cylindrical surface of the clutch outer, one end side in the circumferential direction being rotatably attached to the drive plate and the other end side being displaceable toward the cylindrical surface side of the clutch outer. a fixed-side driven plate having a flange-like protrusion on an outer circumferential surface of a cylindrical fixed-side sleeve, the fixed-side driven plate receiving a driving force from a driving source via a belt to rotate;
a movable-side driven plate having a movable-side plate that projects radially outward like a flange on an outer circumferential surface of a cylindrical movable-side sleeve and sandwiches the belt together with the fixed-side plate, the movable-side driven plate receiving a driving force from the driving source via the belt while approaching or moving away from the fixed-side plate and being driven to rotate;
a sliding sleeve formed in a cylindrical shape and provided between the fixed sleeve and the movable sleeve, the sliding sleeve being provided so as not to be displaceable relative to the fixed sleeve and sliding relative to an inner peripheral surface of the movable sleeve;
a concave cam portion formed by cutting out a spiral shape along an axial direction in one of the sliding sleeve and the movable sleeve;
a pulley device including a convex cam portion on the other of the sliding sleeve and the movable sleeve, the convex cam portion being slidably fitted into the concave cam portion;
a drive plate connected to the fixed sleeve and rotated integrally with the fixed driven plate;
a clutch outer having a cylindrical surface provided concentrically with the drive plate on the outside of the drive plate and connected to a drive shaft;
a clutch weight having a clutch shoe formed to extend along a circumferential direction of the drive plate and facing a cylindrical surface of the clutch outer, the clutch weight having one end side in the circumferential direction rotatably attached to the drive plate and the other end side displaceable toward the cylindrical surface side of the clutch outer,
The sliding sleeve is
A centrifugal clutch provided on the drive plate. 7. The centrifugal clutch according to claim 6 ,
The sliding sleeve is
a cylindrical main body portion provided between the fixed sleeve and the movable sleeve,
The concave cam portion or the convex cam portion is
A centrifugal clutch characterized in that the centrifugal clutch is formed on the outside of the main body portion of the sliding sleeve. 8. The centrifugal clutch according to claim 6 or 7 ,
A centrifugal clutch, characterized in that the sliding sleeve and the movable sleeve are made of different materials. a fixed-side driven plate having a flange-like protrusion on an outer circumferential surface of a cylindrical fixed-side sleeve, the fixed-side driven plate receiving a driving force from a driving source via a belt to rotate;
a movable-side driven plate having a movable-side plate that projects radially outward like a flange on an outer circumferential surface of a cylindrical movable-side sleeve and sandwiches the belt together with the fixed-side plate, the movable-side driven plate receiving a driving force from the driving source via the belt while approaching or moving away from the fixed-side plate and being driven to rotate;
a sliding sleeve that is formed in a cylindrical shape and is provided between the fixed sleeve and the movable sleeve, the sliding sleeve being formed in a cylindrical shape and provided so as not to be displaceable relative to the fixed sleeve and sliding relatively to the movable sleeve;
a concave cam portion formed by cutting out a spiral shape along an axial direction in one of the sliding sleeve and the movable sleeve;
a pulley device including a convex cam portion on the other of the sliding sleeve and the movable sleeve, the convex cam portion being slidably fitted into the concave cam portion;
a drive plate connected to the fixed sleeve and rotated integrally with the fixed driven plate;
a clutch outer having a cylindrical surface provided concentrically with the drive plate on the outside of the drive plate and connected to a drive shaft;
a clutch weight having a clutch shoe formed to extend along a circumferential direction of the drive plate and facing the cylindrical surface of the clutch outer, one end side in the circumferential direction being rotatably attached to the drive plate and the other end side being displaceable toward the cylindrical surface side of the clutch outer,
The sliding sleeve is
A centrifugal clutch provided on the drive plate.