JPH10318342A - V-belt automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability of a bearing and a solution of any rotative lost motion lying between both pulley half bodies by solving a variation in a bearing clearance due to the thermal deformation of both these fast and movable pulley half bodies as the driven pulley side of a V-belt automatic transmission. SOLUTION: This transmission is so constituted that two torque cam mechanisms 75 and 62c, converting a relative rotation lying between both pulley half bodies 61 and 62 into an axial thrust of the movable pulley hald body 62 are equipped at each and side of cylindrical shafts 61a and 62a of both these pulley half bodies 61 and 62. In this case, a bearing lying between these cylindrical shafts 61a and 62a of both the pulley half bodies 61 and 62 is composed of a cylindrical sliding member 65 which is supported by an inner circumferential surface of the cylindrical shaft 62a of the movable pulley hald body 62, and it is equipped with a sliding body part provided with self-lubricity consisting of synthetic resins, and the sliding body part makes its wall thickness compensate a dimensional variation due to heat of the cylindrical shaft 62a of the movable pulley half body 62, and thus it is formed into a thin wall so as to make the bearing clearance between these cylindrical shafts come to being nearly constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-belt automatic transmission employed in a motorcycle or the like, and more particularly to a V-belt automatic transmission between driven cylindrical halves of a driven pulley and a movable pulley half thereof. The present invention relates to a V-belt automatic transmission in which the change in bearing clearance is eliminated to improve the durability of the bearing and to eliminate the rattling of rotation between the two pulley halves.

[0002]

2. Description of the Related Art In an automatic V-belt transmission, an endless V-belt having a V-shaped cross section is bridged between a driving pulley and a driven pulley, and an effective radius of both pulleys is set. Is automatically adjusted according to the engine speed to transmit power. Each pulley holds a V-belt between a fixed pulley half and an axially slidable movable pulley half. The effective radius is changed depending on the axial position of the movable pulley half relative to the fixed pulley half.

Usually, the movable pulley half is urged by a spring so as to approach the fixed pulley half, and acts to increase the effective radius of the sandwiched V-belt, thereby giving tension to the V-belt. However, when the load fluctuation is large, the biasing force of the spring is not enough and a slip occurs between the pulley and the belt. Therefore, the relative rotation between the fixed pulley half and the movable pulley half is used to move the movable pulley in the axial direction. There has been proposed an example of an automatic V-belt transmission having a torque cam mechanism for converting to thrust.

As an example of such a proposal, the applicant has
A patent application for Japanese Patent Application No. 8-101187 was filed earlier (see FIG. 2).
4). In the invention of the present application, the torque cam mechanism includes a movable cam portion 062c formed to extend in the axial direction from an end of the cylindrical shaft 062a of the movable pulley half 062, and a cylindrical shaft 061a of the fixed pulley half 061. A fixed cam portion 075 is formed on the outer periphery of the end portion so as to extend in the radial direction and is engaged with the movable cam portion 062c so as to mesh therewith.
The clearance in the rotation direction between the 62c and the fixed-side cam portion 075 is configured to be small, thereby providing a smooth acceleration feeling and a V-belt automatic transmission with good maintainability of the torque cam mechanism. ing. In the figure, 022 is a gear reducer, 045 is a reducer input shaft, and 047 is a rear axle.

However, in this case, a bearing 027 between the cylindrical shafts 061a and 062a of the two pulley halves 061 and 062 is used.
However, sufficient consideration has not been given to the deterioration of the abrasion resistance due to the thermal expansion and its support. That is, since each of the pulley halves 061 and 062 was integrally cast and formed from aluminum, as a bearing material between the cylindrical shafts 061a and 062a of the two pulley halves 061 and 062, Japanese Patent Laid-Open No. 4-25885 was used.
Although the use of a lubricating synthetic resin as disclosed in Japanese Patent No. 59 was considered, a bearing made of such a material is softer than a metal bearing and has a large thermal expansion. In some cases, it is easily worn, and it has been desired to improve its durability.

Further, both pulley halves made of an aluminum-based material
On the sliding surface of the bearing between the cylindrical shafts 061a and 062a of 061 and 062,
Although it has been considered to apply a hard alumite coating as disclosed in Japanese Utility Model Laid-Open Publication No. 53-107780, in this case, consideration is given to the thermal expansion of each of the cylindrical shafts 061a and 062a. However, there was a rattling of rotation between the two pulley halves 061 and 062 due to a change in bearing clearance.

Further, each cylindrical shaft of both pulley halves 061, 062
Regarding the means for supporting the bearing 027 between 061a and 062a, no consideration has been given in the past, or even if it has been done, the retaining clip is attached to the end of the movable pulley half 062 at the end of the cylindrical shaft 062a. Provided on the inner peripheral surface (Japanese Unexamined Patent Publication No.
224345). In the former case, the bearing may come off, and in the latter case, the cylindrical shaft 06 of the movable pulley half body 062 is provided by the provision of the retaining clip.
2a The end side had to be formed thick.

The movable pulley half 062 has a cylindrical shaft 062a.
When the end side is formed to be thick, the torque cam mechanism is connected to the two pulley halves 061,
When formed on the end side of each of the cylindrical shafts 061a, 062a of 062, the radius of the movable cam portion 062c increases, and as a result,
When the torque acting on the torque cam mechanism is constant, the cam force (force of the movable cam 062c pressing the fixed cam 075 in the rotating direction) generated in the torque cam mechanism is reduced, and the axial component thereof is also reduced. Fixed half 062 Pulley half 061
The pushing force to approach the side becomes small, and it becomes necessary to set a large spring load of the spring 080 for urging the movable pulley half 062 in the same direction. When the spring load is set to be large, the durability of the V-belt 055 always held between the two pulley halves 061 and 062 is reduced by the spring load.

Further, in the invention filed by the applicant of the present invention, the retaining clip 078 of the drive plate 072 of the clutch 070, which is spline-fitted to the end 061b of the cylindrical shaft 061a of the fixed pulley half 061, A normal cut ring-shaped clip is used, and as a result, it tends to expand when centrifugal force is applied, so it is necessary to tighten with an excessive tightening force to withstand this. In addition, the production has to be troublesome, such as selecting a material and performing a process for obtaining a material that can withstand stress. Also, if a nut is used to prevent the retaining, a special space is required in that portion.

Further, in the invention of the applicant of the present invention, the shape of the base portion 061d of the cylindrical shaft 061a of the fixed pulley half body 061 is made such that the stress generated in the portion can be efficiently diffused. For this reason, the shape of the portion was dimensionally increased from the viewpoint of securing strength.

The present invention has been made in view of the above-described problems, and has as its object the purpose of fixing and moving both pulley halves 061, 062 by the respective cylindrical shafts 061a, 062a.
The present invention provides a means for improving the durability of the bearing 027 between them and preventing the bearing 027 from coming off so that the end portions of the cylindrical shafts 061a and 062a of the two pulley halves 061 and 062 do not have to be formed thick. In order to improve the durability and function of the structure on the driven pulley side of the V-belt automatic transmission, reduce the size and weight of the automatic transmission, and the like.

[0012]

The invention described in claim 1 of the present application for achieving the above object is as follows.
A fixed pulley half integrally formed of an aluminum material and supported by a rotating shaft; and a cylindrical shaft of the fixed pulley half formed integrally with an aluminum material to hold the V-belt opposite to the fixed pulley half. A movable pulley half that is slidably supported on the movable pulley half; and a torque cam mechanism that changes a relative rotation of the movable pulley half with respect to the fixed pulley half into an axial thrust of the movable pulley half. In a V-belt automatic transmission provided on a cylindrical shaft end side of a pulley half, a bearing between the cylindrical shaft of the fixed pulley half and the cylindrical shaft of the movable pulley half is formed of a cylindrical sliding member. The sliding member has a self-lubricating sliding member made of a synthetic resin and supported on the inner peripheral surface of the cylindrical shaft of the movable pulley half. But the cylindrical shaft of the fixed pulley half and the movable pulley half By correcting the dimensional change due to heat of the cylinder axis, a V-belt automatic transmission, characterized in that the bearing clearance between the cylindrical axis is formed to be thin so as to be substantially constant.

According to the first aspect of the present invention, since the fixed pulley half and the movable pulley half integrally formed of an aluminum material are deformed by thermal expansion, the invention is configured as described above. Even if the bearing clearance between each of the cylindrical shafts is widened, a bearing made of a sliding member having a self-lubricating sliding body portion made of a synthetic resin having a large coefficient of thermal expansion and a thin wall thickness. However, since the bearing clearance expands to fill the spread, the bearing clearance is always kept substantially constant, the bearing does not wear out, and the durability is improved. In addition, no rattling occurs between the two pulley halves.

According to the second aspect of the present invention, a bearing excellent in heat resistance and corrosion resistance can be obtained.

According to the third aspect of the present invention, a retaining clip for supporting a sliding member constituting a bearing is provided.
It is not necessary to provide the movable pulley half on the inner peripheral surface on the cylindrical shaft end side of the movable pulley half on which the torque cam mechanism is provided. Therefore, it is not necessary to form the cylindrical shaft of the movable pulley half in this portion with a large thickness. The diameter can be reduced, and the radius of the movable cam portion of the torque cam mechanism formed on the end side can be reduced. As a result, the cam force generated in the torque cam mechanism increases, and its axial component also increases, so that the spring load for urging the movable pulley half closer to the fixed pulley half can be set small. The durability of the V-belt sandwiched between these two pulley halves can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the invention described in claims 1 to 3 of the present application shown in FIGS. 1 to 23 will be described below. FIG. 1 is an overall side view of a scooter type motorcycle 1 to which a V-belt automatic transmission according to the present embodiment is applied.

The scooter type motorcycle 1 has a vehicle body front 2
And a rear portion 3 of the vehicle body are connected via a low floor portion 4, and a body frame 5 extending downward from the front portion 2 of the vehicle body and horizontally extending rearward from the floor portion 4 is connected to the rear end of the floor portion. It rises, and furthermore, it slopes obliquely upward and extends to the rear end.

At the front of the body frame 5, a steering handle 6 is provided at the upper end, and a front fork 8 for pivotally supporting the front wheel 7 is pivotally supported at the lower end. A lower front end of a swing-type power unit 20 having a rear end pivotally supporting a rear wheel 9 is pivotally supported on a rear rising portion of the body frame 5 via a link 10 so as to be vertically swingable. When,
The rear cushion 11 is located between the
Is interposed.

The vehicle body front part 2 is covered with a leg shield 15, a step floor 16 is stretched on the floor part 4, and the vehicle body rear part 3 is covered with a body cover 17. The seat 18 is provided.

The power unit 20 is provided with a single-cylinder, two-cycle internal combustion engine 21 disposed at the front, a gear reducer 22 provided at the rear, and between the internal combustion engine 21 and the gear reducer 22. The V-belt automatic transmission 23 is unitized and housed in the unit case 25.

The structure of the power unit 20 is shown in FIG. The unit case 25 includes the V-belt automatic transmission 23
And a left and right long case which accommodates the gear reducer 22 and serves as the left half of the crankcase of the internal combustion engine 21.
26, a right case 27 joined to the front part of the left case 26 to form the right half of the crankcase, a transmission case cover 28 covering the left side of the left case 26, and a gear reducer.
And a gear case 29 that covers 22 from the left.

A crankshaft 31 is rotatably supported by a pair of left and right main bearings 30, 30 in a crankcase formed by a left case 26 and a right case 27. A cylinder block is provided above the crankcase. The cylinder head 21a and the cylinder head 21b are sequentially joined, and an assembly made of these is erected slightly upward and rearward. A piston 32 that slides in the cylinder block 21a is connected to a crankshaft 31 via a connecting rod 33.

At the right end of the crankshaft 31, an AC generator 34 and a cooling fan 35 are provided.
An engine cover 36 covers the outer periphery of the C generator 34 and the cooling fan 35.

At the left end of the crankshaft 31, a driving pulley 40 of the V-belt automatic transmission 23 is provided. In the drive pulley 40, a fixed pulley half 41 fixed to the left end of the crankshaft 31 and a movable pulley half 42 supported slidably in the axial direction on the crankshaft 31 are opposed to each other. A plurality of centrifugal weights 44 are provided between the pulley half 42 and the ramp plate 43 fixed to the crankshaft 31.
Are movably accommodated in the radial direction.

When the centrifugal weight 44 moves in the centrifugal direction, the movable pulley half 42 comes closer to the fixed pulley half 41, and the V-belt 55 held between the two pulley halves 41, 42 is effectively used. The radius can be increased.

On the other hand, the rear part of the left case 26 and the gear case 29
As shown in FIG. 3, an intermediate shaft 46 is provided between a speed reducer input shaft 45 and a rear axle 47 which is a speed reducer output shaft. A large-diameter intermediate gear 49 fitted on the intermediate shaft 46 meshes with an input gear 48 fitted on the shaft 45, and is fitted on the rear axle 47 on a small-diameter intermediate gear 50 fitted on the same intermediate shaft 46. The output gear 51 thus engaged meshes to form a speed reduction mechanism.

As shown in FIG. 3, this gear reducer
A driven pulley 60 and a clutch 70 are provided in the left half of the 22 reduction gear input shaft 45 that passes through the gear case 29. The driven pulley 60 comprises a pair of opposed fixed pulley halves 61 and movable pulley halves 62 both made of aluminum.

As shown in FIG. 7, fixed pulley halves
In 61, the inner peripheral portion of the main body extends in the axial direction to form a cylindrical inner sleeve portion (cylindrical shaft) 61a. The end of the inner sleeve portion 61a has a slightly reduced diameter and serrations on the outer periphery. An engraved mounting portion 61b is formed, and an end portion of the mounting portion 61b is fitted with a wire-type clip 78 for retaining a drive plate 72 of a clutch 70, which will be described later, in a substantially semicircular cross section. An arcuate clip groove 61c is provided around the periphery. The fixed pulley half 61, from the main body to the mounting portion 61b,
It is integrally molded by aluminum die casting.

Further, since a large stress is generated at the root 61d of the inner sleeve portion 61a of the fixed pulley half 61 by the tension of the V-belt 55, conventionally, this portion has a large size to secure the strength. However, in the present embodiment, the apex angle α (α ₁ , α ₁ , tangent) of the tangent line that is in contact with the maximum curvature curve among the plurality of curvature curves constituting the cross-sectional contour of the portion is formed. α ₂ etc.) are formed in a shape such that they are equal to or larger than a predetermined angle (see FIGS. 7 and 8).

By doing so, the conventional fixed pulley half
Without changing the basic shape of 61, the stress generated at the root 61d can be efficiently diffused and the strength of the portion is maintained, so that the strength of the portion can be obtained with a smaller size and shape. Miniaturization of the fixed pulley half 61,
The weight can be reduced.

In the present embodiment, the outer diameter D ₁ of the inner sleeve portion 61a of the fixed pulley half 61 = 34 mm, the outer diameter D ₂ of the main body of the fixed pulley half 61 = 118 mm, and the maximum diameter D _{3 of the} base 61d. Α = 90 ° when the maximum thickness t of the main body of the fixed pulley half 61 = 5 mm, the inclination angle β = 15 °, and the maximum curvature R ₃ of the contour of the base 61d = 5.5 mm = 45 mm. Then, the stress generated in the root portion 61d could be diffused most efficiently. At this time, the curvature R ₁ of the contour adjacent to the contour having the maximum curvature R ₃ = 5.5 mm of the root 61d,
R ₂ was R ₁ = 2.2 mm and R ₂ = 2.0 mm.

On the other hand, as shown in FIGS. 4 and 5, the movable pulley half 62 has an inner peripheral portion extending in the axial direction, and has an inner diameter smaller than the inner sleeve portion 61a of the fixed pulley half 61. Is slightly larger cylindrical outer sleeve (cylindrical shaft)
At the end of the outer sleeve portion 62a, projections 62b having an arc-shaped cross section at three locations are formed in the end portion of the outer sleeve portion 62a so as to protrude in the axial direction, and the tip of the projection 62b rotates clockwise in FIG. The movable cam portion 62c is formed by bending in the direction. The movable side cam portion 62c is formed with an outward cam surface 62co and an inward cam surface 62ci whose front and rear end surfaces in the circumferential direction are inclined.

In the present embodiment, the three movable side cam portions 62c are provided with triangular bulges in the direction opposite to the rotation (clockwise direction in FIG. 4) to form inward cam surfaces 62ci. The inward cam surface 62ci restricts relative rotation with respect to a fixed cam portion 75 described later, and does not receive a large load. Therefore, the inward cam surface 62ci protrudes only to one of the three movable cam portions 62c. It is sufficient if a portion is provided to form the inward cam surface 62ci (see FIG. 6). The movable pulley half 62 is integrally cast from the main body to the movable cam portion 62c by aluminum die casting.

The outer peripheral portion of the base of the outer sleeve portion 62a in the main body of the movable pulley half 62 is annularly formed with a groove 62.
d is formed. Further, the outer sleeve portion 62a of the movable pulley half 62 and the inner sleeve portion 61a of the fixed pulley half 61 are provided at the end of the inner peripheral portion of the movable pulley half 62 opposite to the outer sleeve portion 62a. A clip groove 62e into which a retaining clip 66 (see FIGS. 13 and 14) for preventing a bearing bush 65 described later, which is interposed therebetween, from coming off is provided.

As shown in FIGS. 13 and 14, a wire-type clip is used as the retaining clip 66, so that it is the same as a wire-type clip 78 for retaining the drive plate 72 of the clutch 70 described later. When this is fitted into the clip groove 62e, the elastic restoring force causes the shoulder at the right end of the bearing bush 65 to rebound,
Since this is urged toward the end of the outer sleeve portion 62a, it is reliably prevented from coming off.

The driven pulley 60 constructed as described above
Of the fixed pulley half 61, as shown in FIG. 3, the inner sleeve portion 61a is penetrated by the reduction gear input shaft 45, and the needle bearing 63 and the ball bearing
The movable pulley half 62 has an outer sleeve portion 62a on the outer circumference of the inner sleeve portion 61a of the fixed pulley half 61 via a bearing bush 65 via a bearing bush 65. It is slidably supported and supported by it. The movable pulley half 62 is opposed to the fixed pulley half 61, and is supported so as to be able to slide relatively in the axial direction and to rotate in the circumferential direction.

In the present embodiment, the bearing bush (sliding member) 65 is, as shown in detail in FIGS. 10 and 11, a back metal part having a steel material surface plated with copper. On the inner peripheral surface of the layer 65a, a self-lubricating sliding body portion 65b layer made of a synthetic resin (polytetrafluoroethylene) is fixedly formed. Bearing bush 65
The movable pulley half 62 is press-fitted into the inner peripheral surface of the outer sleeve portion 62a and held by the outer sleeve portion 62a.
The surface layer of the inner sleeve portion of the fixed pulley half 61
Due to its self-lubricating property, the outer peripheral surface of the movable pulley half 62 is smoothly slidably contacted with the fixed pulley half 61 by the self-lubricating property. In FIG. 11, reference numeral 65c denotes a sintered layer for facilitating the fixing of the sliding member 65b to the back metal portion 65a.

Moreover, the sliding member of the bearing bush 65
The layer 65b has a larger coefficient of thermal expansion than aluminum which is a constituent material of the two pulley halves 61 and 62, and is formed to be thin with a predetermined thickness, so that the inner sleeve portion 61a of the fixed pulley half 61 is formed. And a dimensional change b (a <b) of the inner diameter of the outer sleeve portion 62a of the movable pulley half 62 due to the heat of the outer diameter of the movable pulley half 62. Then, the bearing clearance c is expanded to just fill the expansion amount d, and the bearing clearance c is maintained at a substantially constant initial value (see FIG. 12).

Therefore, the bearing bush 65 expands more than the amount of expansion of the bearing clearance c due to the expansion of the sleeve portions 61a, 62a of the two pulley halves 61, 62, and the sliding surfaces thereof are more intense. The occurrence of dynamic wear and the occurrence of rotation play between the two pulley halves 61 and 62 of the driven pulley 60 due to the expansion of the bearing clearance c are prevented.

In the present embodiment, the outer diameter D ₁ of the inner sleeve portion 61a of the fixed pulley half 61 = 34 mm, the inner diameter D ₄ of the outer sleeve portion 62a of the movable pulley half 62 = 37 mm, and the thickness of the bearing bush 65. when h = 2 mm, the thickness h ₁ of the sliding body portion 65b is by setting the thin 0.75 mm, it was possible to keep the bearing clearance c to the initial substantially constant magnitude of. Such dimensioning of the thickness h ₁ of the sliding body part 65b is, for example, by machining the surface layer of the sliding body portion 65b, can be easily performed.

The bearing bush 65 is provided with two pulley halves 6.
When interposed between the respective sleeve portions 61a, 62a of 1, 62,
One end thereof is the outer sleeve portion 62 of the movable pulley half 62.
a, the other end of which is opposite to the outer sleeve portion 62a of the inner peripheral portion of the main body of the movable pulley half 62, as described above. It is supported by a retaining clip 66 fitted into a clip groove 62e formed at the end on the side, and its axial movement is restricted.

Accordingly, the clip 66 for preventing the bearing bush 65 from slipping off is not disposed on the inner peripheral surface of the movable sleeve half 62 on the side of the protrusion 62b of the outer sleeve portion 62a. And the outer diameter can be reduced, so that when the torque acting on the torque cam mechanism is constant, the cam force generated in the torque cam mechanism can be increased, and the movable pulley in the axial direction can be increased. Since the component force pushing the half 62 toward the fixed pulley half 61 can also be increased, the spring load of the spring 80 for urging the movable pulley half 62 in the same direction can be set small, and both pulley half The durability of the V-belt 55 sandwiched between 61 and 62 can be improved.

Next, the clutch 70 and the torque cam mechanism will be described. A clutch 70 is provided at the left end of the attenuator input shaft 45 and at the left end mounting portion 61b of the inner sleeve portion 61a of the fixed pulley half 61. The clutch outer 71 having a flat bottomed cylindrical shape of the clutch 70 has a bottom wall 71a having a center hole fitted into the left end thread portion of the reduction gear input shaft 45 via a collar 79, and screwed and tightened with a nut 74. Further, the peripheral side wall 71b is formed so as to open rightward.

Inside the clutch outer 71,
Left end mounting part of inner sleeve part 61a of fixed pulley half 61
As shown in FIG. 3, a drive plate 72, which is a clutch inner, is attached to 61b by serration fitting.

Further, to prevent the serration fitting from being loosened, the wire type clip 78 is attached to the mounting portion 61.
a clip groove 61c having a substantially semi-circular cross section provided around the end of b
And is in elastic contact with a chamfered portion 72e of a serration fitting portion 72a of the drive plate 72, which will be described later, thereby constantly biasing the drive plate 72 toward the main body side of the fixed pulley half 61. (See FIGS. 21 to 23).

As shown in the figure, the wire type clip 78 is a ring-shaped clip whose arc portion is slightly cut off and cut off, and both ends thereof are staggered by a predetermined small amount in a natural state. since the shape and which is fitted into the clip groove 61c, the elastic restoring force F _1, since pushing strongly axially beveled portion 72e of the drive plate 72 (main body side direction of the stationary pulley half 61) , the driven pulley 60 is rotated at high speed, even the centrifugal force F ₂ is applied to the wire type clip 78 with respect to the resultant force F of these forces, the reaction force from the contact point between the wire type clip 78 of the chamfered portion 72e Working effectively, the diameter of the clip 78 is prevented from expanding and does not come off. Moreover, such a wire type clip 78 has a simple structure, is inexpensive, and can be easily laid out even in a small space.

As shown in FIGS. 15 and 16,
The drive plate 72 has a flat cylindrical serration fitting portion 72a formed on an inner peripheral edge thereof.
A core 72b extends in the radial direction from the outer peripheral surface of the core 72b.
b, the outer peripheral plate portion 72c is connected with a slight step.

Three pins 73 are implanted in the outer peripheral plate portion 72c at equal intervals in the circumferential direction.
74 is supported (see FIG. 3). A fixed side cam portion 75 made of a resin having self-lubricating properties is integrally molded with the core portion 72b and provided at three locations at equal intervals in the circumferential direction.

A gap 72d is provided between the fixed side cam portions 75.
The three movable cam portions 62c of the movable pulley half 62 face the three gaps 72d, and the fixed cam portion 75 and the movable cam portion 62c made of resin are engaged with each other. Engage. As shown in FIG. 17, the fixed side cam portion 75 made of resin is fixed to the distorted core portion 72b, has a substantially trapezoidal cross section, and is an inwardly facing flat surface whose front and rear end surfaces are inclined in the circumferential direction. It has a cam surface 75i and an outward cam surface 75o that is a curved surface.

The drive plate 72 is disposed in the clutch outer 71, and the clutch shoe 74 supported by the pin 73 swings radially outward against the clutch spring 76 by centrifugal force. A friction member 74a provided on the outer periphery of the clutch shoe 74 comes into contact with and engages with the inner peripheral surface of the peripheral side wall 71b of the clutch outer 71.

The drive plate 72 includes a fixed pulley half 61.
The drive plate 72 rotates integrally with the fixed pulley half 61 because the inner surface of the inner sleeve 61a is serrated and fitted integrally with the inner sleeve 61a.

As shown in FIG. 3, the movable pulley half 62 slidably supported between the drive plate 72 and the main body of the fixed pulley half 61 has an outer sleeve portion.
A spring 80 made of spring steel is provided around the outer periphery of 62a, and the spring 80 is interposed between the drive plate 72 and the movable pulley half 62 to fix the movable pulley half 62 to a fixed pulley. It is biased in a direction to approach the half body 61.

A resin spring guide 81 is provided in a gap between the inner periphery of the spring 80 and the outer periphery of the outer sleeve portion 62a.
Is interposed. The spring guide 81 has a cylindrical shape as shown in FIG.
The inner diameter is slightly larger than the outer diameter of the outer sleeve portion 62a, and the inner diameter on the flange 81a side is slightly enlarged.

The spring guide 81 is connected to the outer sleeve part.
When the drive plate 72 is mounted on the left end mounting portion 61b of the inner sleeve 61a, the fixed cam portion 75 made of resin fits into the enlarged inner diameter portion of the spring guide 81, and the spring guide 81 , And the flange 81a of the spring guide 81 abuts the step portion 72f on the inner periphery of the outer peripheral plate portion 72c of the drive plate 72.

On the other hand, an annular groove 62d provided on the outer peripheral portion of the base of the outer sleeve portion 62a of the movable pulley half 62.
A spring seat 82, which is an annular iron plate made of iron, is fitted into the spring seat 82 and the spring guide 81.
A spring 80 is interposed at both ends with the flange 81a (see FIGS. 1, 4 and 5).

In this way, the front portion is wound around the drive pulley 40 between the movable pulley half 62 and the fixed pulley half 61 urged toward the fixed pulley half 61 by the spring 80. The rear of the V-belt 55 is pinched and wrapped around,
It acts to increase the effective radius of the wound V-belt 55, and thereby the V-belt 55 can be tensioned.

The outer sleeve of the movable pulley half body 62
The three movable cam portions 62c at the left end of 62a are formed with three gaps of the drive plate 72 which rotates integrally with the fixed pulley half 61.
Three fixed side cam parts 75 made of resin facing 72d, respectively.
Are engaged with each other. The engagement state of these three movable cam parts 62c and three fixed cam parts 75 is
This is illustrated in FIG.

In FIG. 18, the inward cam surface 75i and the outward cam surface 75o of the fixed cam portion 75 face the inward cam surface 62ci and the outward cam surface 62co of the movable cam portion 62c, respectively. The clearance C in the rotation direction is small, and the opposing cam surfaces come into contact easily. Therefore, the relative rotation angle of the movable cam portion 62c with respect to the fixed cam portion 75 is restricted to be small.

The V-belt automatic transmission 23 in the present embodiment
Is configured as described above, and operates as follows. When the rotational speed of the internal combustion engine 21 is low, as shown by a solid line in FIG.
The centrifugal weight 44 moving along 43 is on the center side,
The movable pulley half 42 is separated from the fixed pulley half 41, and the effective radius of the winding of the V-belt 55 is small. Therefore, on the driven pulley 60 side, the movable pulley half 62 is urged by the spring 80 and the fixed pulley half It approaches the body 61 and acts to increase the effective radius of the winding of the V-belt 55, and power is transmitted at a large reduction ratio.

When the engine rotation speed increases, the centrifugal weight 44 moves in the centrifugal direction, as shown by the two-dot chain line in FIG. 2, and the movable pulley half 42 on the drive pulley 40 side moves to the fixed pulley half 41. Approaching, the effective radius of the winding of the V-belt 55 increases, and therefore the driven pulley 60 side
The movable pulley half 62 separates from the fixed pulley half 61 in opposition to this, the effective radius of the winding of the V-belt 55 decreases, and the reduction ratio gradually decreases. In this case, the clutch 70 is also in the engaged state. Thus, the rotation speed of the rear wheel 9 is increased.

When the engine rotation speed increases, the movable pulley half 62 moves in the direction away from the fixed pulley half 61 as described above, so that the movable side cam portion 62c integral with the movable pulley half 62 is As shown by the two-dot chain line in FIG.
This will penetrate deeply into the space 72d between the fixed side cam portions 75. The movable side cam portion 62c indicated by the two-dot chain line in FIG.
A TOP ratio state with such a small reduction ratio is shown. Also, the movable cam portion 62c indicated by a solid line in the figure shows the LOW ratio state of the large reduction ratio.

When the tension of the V-belt 55 suddenly increases due to sudden acceleration at the time of starting or the like, the fixed pulley half 61 and the V-belt 55 connected to the rear wheel 9 and receiving a large load.
And a movable pulley half 62 that can rotate relative to the fixed pulley half 61 has a rear wheel 9.
Of the movable pulley 62, V
Attempts to rotate together with belt 55.

Therefore, the movable pulley half 62 rotates relative to the fixed pulley half 61, so that the movable cam portion 62 c integral with the movable pulley half 62 is integrated with the fixed pulley half 61. Of the fixed side cam portion 75 fixed to the drive plate 72 of
As shown in FIG. 18, the movable-side cam portion 62c moves relatively to the fixed-side cam portion 75 in the direction of arrow A.

Then, the outward cam surface 62co of the movable cam portion 62c abuts against the outward cam surface 75o of the fixed cam portion 75, and the movable cam portion 62c exerts a force in the direction of arrow B by a reaction. As a result, the movable pulley half 62 is brought closer to the fixed pulley half 61, and the clamping pressure of the V-belt 55 is increased.
55 slip will be prevented.

Since the fixed cam portion 75 and the movable cam portion 62c are engaged with each other so that the clearance C between them is small, the outward cam surface 62co of the movable cam portion 62c is fixed to the fixed cam portion 75. Even at a distance from the outward cam surface 75o, the clearance C is small at the maximum.
When the cam surfaces 62co and 75o are in contact with each other, the torque cam mechanism operates,
The time lag until the slip is prevented is short, the acceleration delay is almost prevented, and a smooth acceleration feeling can always be obtained.

FIG. 19 is a graph showing the relationship between the engine speed Ne and the vehicle speed V. At a certain engine speed n ₀ , the clutch
When the power is transmitted to the rear wheel 9 by the engagement of the clutch 70, the torque cam mechanism operates as described above, and the clutch is accelerated without delay after engaging the clutch as shown by the solid line. In the same figure, the broken line shows the case of the conventional torque cam mechanism,
After the clutch is engaged, the V-belt 55 has a long slip time, has a delay in acceleration, and is in a starting state lacking in a feeling of acceleration.

The fixed cam portion 75 and the movable cam portion 62c
And the inward cam surface 75i and the outward cam surface 75o of the fixed-side cam portion 75 made of resin are the inward cam surface 62ci and the outward cam surface of the movable cam portion 62c, respectively.
Since it comes in contact with 62co, there is little wear and fatigue, and it has excellent durability. Further, since the three movable cam portions 62c are formed integrally with the shaft end of the outer sleeve portion 62a, the maintainability is good.

Along with the fixed pulley half 61, the movable pulley half 62 also has an outer sleeve portion 62a and a movable cam portion 62c.
Since aluminum is integrally cast and formed, the number of parts is reduced, the structure is simplified, and productivity can be improved.

Since the fixed cam portion 75 made of resin is also molded integrally with the core portion 72b of the drive plate 72, the operation of separately manufacturing and mounting the cam portion is omitted.
Productivity can be further improved.

As shown in FIG. 17, the core portion 72b of the drive plate 72 branches into two portions with respect to one fixed-side cam portion 75, and has a bent cross-section. Fixed resin cam section integrally molded
75 is firmly fixed and no backlash occurs.

The fixing structure of the fixed cam portion 75 can be variously considered. For example, as shown in FIG. 20, the core portion 90 of the drive plate 72 may have a complicatedly distorted cross-sectional shape. By being molded integrally with the distorted core portion 90, the fixed cam portion 91 made of resin is firmly fixed without play. FIG. 20 is a developed view showing an engagement state between the fixed cam portion 91 and the movable cam portion 92, and the shapes of the cam portions 91 and 92 are substantially the same as those in the above embodiment.

In this embodiment, the bearing bush 27 is employed as a bearing between the inner sleeve portion 61a of the fixed pulley half 61 and the outer sleeve portion 62a of the movable pulley half 62. In addition, since a bush as a separate part is required, the number of parts increases, and the assembling process becomes complicated. Thus, instead of this, the following means may be adopted.

That is, the outer peripheral surface of the inner sleeve portion 61a of the fixed pulley half 61 and the inner peripheral surface of the outer sleeve portion 62a of the movable pulley half 62 are each subjected to an anodic oxide film treatment, and Impregnate a lubricant such as molybdenum sulfide. Thus, the bearing between the inner sleeve portion 61a of the fixed pulley half 61 and the outer sleeve portion 62a of the movable pulley half 62 is a coaxial structure bearing formed integrally with these sleeves (cylindrical shaft). Configure. And apply grease between these two coaxial bearings,
Seal with an oil seal.

In this case, the driven pulley 60 is rotated by the winding of the V-belt 55, and the inner sleeve portion 61a of the fixed pulley half 61 and the outer sleeve portion 62a of the movable pulley half 62 thermally expand. Also, since the heat of the bearing portion is good, the change in the bearing clearance between them can be reduced.

Further, since the bearing is constituted by the surface treatment of the sliding surface of the bearing portion and the grease, there is no need for a separate part such as a bearing bush and the number of parts is reduced, and the assembling process is simplified. Is done. In addition, the weight can be reduced accordingly.

[Brief description of the drawings]

FIG. 1 is an overall side view of a scooter type motorcycle to which a V-belt automatic transmission according to an embodiment of the present invention described in claims 1 to 3 of the present application is applied.

FIG. 2 is a cross-sectional view of the power unit taken along the line II-II in FIG.

FIG. 3 is a sectional view of a main part of a rear part of the power unit in FIG. 2;

FIG. 4 is a side view of the movable pulley half in the embodiment of FIG. 1;

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is a view similar to FIG. 4 of a modified example of a movable pulley half.

FIG. 7 is a sectional view of a fixed pulley half in the embodiment of FIG. 1;

8 is an enlarged view of a contour shape of a portion VIII in FIG. 7;

FIG. 9 is a sectional view of a spring guide in the embodiment of FIG. 1;

FIG. 10 is a sectional view of the bearing bush in the embodiment of FIG. 1;

FIG. 11 is an enlarged view of an XI part in FIG. 10;

FIG. 12 is a view for explaining an operation of the bearing bush in the embodiment of FIG. 1;

FIG. 13 is a front view of the retaining clip in the embodiment of FIG. 1;

FIG. 14 is a side view of the same.

FIG. 15 is a side view of the drive plate in the embodiment of FIG.

FIG. 16 is a sectional view taken along line XVI-XVI in FIG. 15;

FIG. 17 is a sectional view taken along the line XVII-XVII in FIG.

FIG. 18 is a developed view showing an engagement state between the fixed cam portion and the movable cam portion in the embodiment of FIG.

FIG. 19 is a diagram showing a relationship between an engine speed and a vehicle speed in the embodiment of FIG. 1;

FIG. 20 is a developed view showing an engagement state between a modified example of the fixed cam portion and the movable cam portion, and is a view similar to FIG. 18;

FIG. 21 is a front view of the wire type clip for retaining in the embodiment of FIG. 1;

FIG. 22 is a side view of the same.

FIG. 23 is an enlarged view of a part XXIII in FIG. 3;

FIG. 24 is a sectional view showing a conventional pulley structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scooter type motorcycle, 2 ... body front part, 3 ... body rear part, 4 ... floor part, 5 ... body frame, 6 ... steering wheel, 7 ... front wheel, 8 ... front fork, 9 ... rear wheel, 10 ...
Link, 11 ... rear cushion, 15 ... leg shield, 16
… Step floor, 17… body cover, 18… seat, 20
... power unit, 21 ... internal combustion engine, 22 ... gear reducer, 23
... V-belt automatic transmission, 25 ... Unit case, 26 ... Left case, 27 ... Right case, 28 ... Transmission case cover, 29 ...
Gear case, 30… Main bearing, 31… Crank shaft, 32…
Piston, 33 connecting rod, 34 AC generator, 35 cooling fan, 36 engine cover, 40 drive pulley, 41 fixed pulley half, 42 movable pulley half,
43 ... Ramp plate, 44 ... Centrifugal weight, 45 ... Reducer input shaft, 46 ... Intermediate shaft, 47 ... Rear axle, 48 ... Input gear, 49 ... Intermediate gear, 50 ... Intermediate gear, 51 ... Output gear, 55 ... V belt,
60: driven pulley, 61: fixed pulley half, 61a: inner sleeve part (cylindrical shaft), 62: movable pulley half, 62a: outer sleeve part (cylindrical shaft), 62c: movable cam part, 63: needle bearing , 64: ball bearing, 65: bearing bush (sliding member), 65b: sliding member, 66: retaining clip, 70: clutch, 71: clutch outer, 72 ...
Drive plate, 73 Pin, 74 Nut, 74 Clutch shoe, 75 Fixed cam, 76 Clutch spring, 78 Wire clip for retaining, 79 Collar, 80 Spring, 81 Spring guide, 82: spring seat, 90: core, 91: fixed cam, 92: movable cam.

Claims (3)

[Claims] 1. A fixed pulley half integrally formed of an aluminum material and supported by a rotating shaft, and a fixed pulley integrally formed of an aluminum material to hold a V-belt opposed to the fixed pulley half. A movable pulley half slidably supported by a half cylindrical shaft, and a relative rotation of the movable pulley half with respect to the fixed pulley half is converted into an axial thrust of the movable pulley half. In a V-belt automatic transmission provided with a torque cam mechanism on a cylindrical shaft end side of the two pulley halves, a bearing between the cylindrical shaft of the fixed pulley half and the cylindrical shaft of the movable pulley half has a cylindrical shape. A sliding member which is supported on an inner peripheral surface of a cylindrical shaft of the movable pulley half and has a self-lubricating property made of a synthetic resin; Has a thickness equal to that of the cylindrical shaft of the fixed pulley half. An automatic V-belt transmission characterized in that it is formed thin so as to correct a dimensional change due to heat of a cylindrical shaft of a movable pulley half and to make a bearing clearance between the cylindrical shafts substantially constant. 2. The V-belt automatic transmission according to claim 1, wherein the sliding member is formed by forming a polytetrafluoroethylene layer into a thin wall by machining. 3. The V-belt according to claim 1, wherein the sliding member is prevented from being removed by a retaining clip on the opposite side of the sliding member from the torque cam mechanism. Automatic transmission.