JPH09287638A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of waviness phenomenon of a spring without a spring guide, to reduce the number of parts, and to facilitate an assembly work. SOLUTION: A continuously variable transmission is formed such that a fixed pulley half body 61 and a moving pulley half body 62 are fitted in inner and outer cylinders 55 and 58, respectively, slidably fitted in each other and pivotally supported to each other and a V-belt 52 is nipped between the conical surfaces, positioned facing each other, of the fixed and moving pulley half-bodies 61 and 62. In the continuously variable transmission, a spring 80 to press the moving pulley half body 62 peripherally arranged around the outer cylinder 58 in the direction of the fixed half-body pulley 61 has two end parts diameters of which are smaller than that of a central part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt type continuously variable transmission adopted in motorcycles and the like.

[0002]

2. Description of the Related Art In a belt type continuously variable transmission, an endless V belt having a V-shaped cross section is spanned between a driving pulley and a driven pulley, and the effective radii of both pulleys are automatically adjusted according to the engine speed. Each pulley has a V-belt sandwiched between a fixed pulley half and a movable pulley half that is slidable in the axial direction. The effective radius is changed according to the relative position of the body in the axial direction.

FIG. 4 is a sectional view of a driven pulley side of a conventional continuously variable transmission, in which an inner sleeve 02 is rotatably attached to a reduction gear input shaft 01 of a reduction gear having a rear axle as an output shaft. The outer sleeve 03 is supported on the outer circumference of the inner sleeve 02.
Is slidably supported on the inner sleeve 02.

A driven pulley 04 is provided at the right ends of the inner sleeve 02 and the outer sleeve 03.
Is composed of a fixed pulley half body 05 fitted to the right end portion of the inner sleeve 06 and a movable pulley half body 06 fitted to the right end portion of the outer sleeve 03. The movable pulley half body 060 and its conical surface face each other, and the V-belt 07 is sandwiched between them.

A clutch 08 is provided at the left end portions of the reduction gear input shaft 01 and the inner sleeve 02, and the outer periphery of a drive plate 09 fitted to the left end portion of the inner sleeve 02 is attached to the left end portion of the reduction gear input shaft 01. It is covered by the clutch outer 010 that is fitted to the section. A spring 015 provided around the outer sleeve 03 is interposed between the drive plate 09 and the movable pulley half body 06, and the spring 015 urges the movable pulley half body 06 toward the fixed pulley half body 05 side. V
The belt 07 is pinched.

The outer sleeve 03 is formed with a long hole 03a along the axial direction and slightly inclined in the circumferential direction. The torque pin projecting from the inner sleeve 02 is formed in the long hole 03a.
02a engages to guide the sliding of the outer sleeve 03 with respect to the inner sleeve 02. A cylindrical seal cover 016 is fitted on the outer circumference of the outer sleeve 07 via an O-ring, and the opening surface of the slot 07a is oil-tightly covered by the seal cover 016, and the slot 07a is filled with grease. To be done.

[0007] The same outer cover of the outer sleeve 03
A cylindrical spring guide 017 is provided between the inner periphery of 016 and the spring 015 so as to be in contact with one end of the drive plate 09 and partially overlap the seal cover 016.

The spring guide 017 and the seal cover 01
Both ends are in contact with each flange of 6 and the spring 01
5 is installed. Incidentally, Japanese Utility Model Publication No. 63-4842 describes an example in which a spring guide is not provided.

[0009]

[Problems to be Solved by the Invention] However, the spring 015
Is a cylindrical compression coil spring, which is in a compressed state by being sandwiched between the drive plate 09 and the movable pulley half body 06, and which does not have a spring guide as in the example described in the above publication, has a cylindrical shape. -Shaped spring 015 is partly eccentric and the spring cylindrical surface is likely to wavy. When such spring 015 rotates together with the rotation of driven pulley 08, the rotational balance cannot be maintained and the partial eccentricity increases and the cylindrical surface The ripple phenomenon expands.

Therefore, due to this waving phenomenon, the spring 025 may hit the clutch shoe on the outer periphery of the central portion, the seal cover 016 on the inner periphery, or the like, and may make an abnormal noise.

Therefore, as shown in FIG. 4, the spring guide 017 is used.
This supports the inner circumference of the spring 025 and prevents the waving phenomenon, but the number of parts is large and the assembly work is troublesome.

The present invention has been made in view of the above points, and an object of the present invention is to provide a continuously variable transmission in which a spring waviness phenomenon is prevented without a spring guide, and the number of parts is small and the assembling work is easy. The point is to provide at low cost.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a fixed pulley half body and a movable pulley half in an inner cylinder and an outer cylinder which are slidably fitted to each other and axially supported. In a continuously variable transmission in which a half body is fitted, and a V belt is sandwiched between conical surfaces of the fixed pulley half body and the movable pulley half body, which face each other, the movable pulley half is provided around the outer cylinder. In the continuously variable transmission, the spring for pressing the body toward the fixed pulley half body has a smaller diameter at the central portion than at both ends.

Since the diameter of the central portion of the spring is smaller than that of both ends thereof, the central portion having the smaller diameter is pressed by the both end portions having the larger diameter, and the spring itself restricts the eccentricity of the central portion. It has a function to prevent the occurrence of waviness on the cylindrical surface of the spring, and prevents the generation of abnormal noise due to spring interference without a spring guide.
It is possible to prevent deterioration of durability due to wear.

Since the spring guide is not required, the number of parts is small, the assembling work is easy, and the cost can be reduced.

The continuously variable transmission according to claim 1, wherein the spring has a shape in which a diameter is gradually reduced from both end portions to a central portion, whereby the elastic function inherent to the spring is sufficiently maintained and the rotational balance is maintained. Easy to take.

A specially-dedicated member is used in the continuously variable transmission according to claim 1 or 2, wherein the spring has a small-diameter central portion that presses the seal cover covering the outer peripheral surface of the outer cylinder from the outside. It is possible to improve the oil tightness of the seal cover.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is an overall side view of a scooter type motorcycle 1 to which the continuously variable transmission is applied.

A vehicle body front portion 2 and a vehicle body rear portion 3 are connected via a low floor portion 4, and a vehicle body frame 5 extending downward from the vehicle body front portion 2 and then horizontally extending the floor portion 4 rearward. Rises from the rear end of the floor portion, further tilts rearward 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 pivotally supporting a front wheel 7 is pivotally supported at the lower end. At the rising portion of the vehicle body frame 5, the lower part of the front end of a swing type power unit 20 having a rear wheel 9 pivotally supported at the rear end is pivotally supported up and down via a link 10, and the upper surface of the rear part of the power unit 20 is supported. A rear cushion 11 is interposed between the vehicle body frame 5 and an upper portion thereof.

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

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

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

A crankshaft 31 is rotatably supported by a pair of left and right main bearings 30 in a crankcase formed by a left case 26 and a right case 27.
A cylinder block 21a and a cylinder head 21b are joined from the same crankcase 21 and stand upright with a slight rearward inclination. The piston 32, which slides in the cylinder block 21 a, is connected to the crankshaft 31 via a connecting rod 33.

An AC generator 34 and a cooling fan 35 are provided at the right end of the crankshaft 31, and the internal combustion engine 21, AC
Engine cover around the generator 34 and cooling fan 35
36 covers.

A drive pulley 40 of the continuously variable transmission 23 is provided at the left end of the crankshaft 31.
The fixed pulley half 41 fixed to the left end of the crankshaft 31 and the movable pulley half 42 axially slidably supported by the crankshaft 31 face each other. A centrifugal weight 44 is housed between 42 and a ramp plate 43 fixed to the crankshaft 31 so as to be movable in the radial direction.

By the movement of the centrifugal weight 44 in the centrifugal direction, the movable pulley half body 42 comes closer to the fixed pulley half body 41, and the effective radius of the V-belt 52 sandwiched between the pulley half bodies 41 and 42 is set. Can be large.

On the other hand, in the gear reducer 22 disposed in the rear portion of the left side case 26 and in the gear case 29, an intermediate shaft 46 is provided between a reducer input shaft 45 and a rear axle 47 which is a reducer output shaft. A large diameter intermediate gear 49 fitted to the intermediate shaft 46 meshes with an input gear 48 fitted to the speed reducer input shaft 45, and a rear axle 47 is attached to a small diameter intermediate gear 50 fitted to the same intermediate shaft 46. The output gear 51 fitted to the gear meshes with each other to form a reduction mechanism.

The left half driven pulley 60 and clutch 70 that penetrate the gear case 29 of the speed reducer input shaft 45 of the gear speed reducer 22.
Is provided. As shown in FIG. 3, the reducer input shaft 45
The inner sleeve 55 is rotatably supported by a needle bearing 56 and a ball bearing 57, and one fixed pulley half 61 of the driven pulley 60 of the right end of the inner sleeve 55 is driven.
Is fitted.

An outer sleeve is provided around the inner sleeve 55.
58 is slidably fitted, the other movable pulley half 62 of the driven pulley 60 is fitted on the right end of the outer sleeve 58, and the movable pulley half 62 and the fixed pulley half 61 are The conical surfaces are opposed to each other, and the V-belt 52 is sandwiched therebetween.

A cylindrical outer sleeve 58 slidably fitted to the outer periphery of the inner sleeve 55 is provided with a long hole 58a along the axial direction and slightly inclined in the circumferential direction. The torque pin 55 protruding from the inner sleeve 55.
a is engaged to guide the sliding of the outer sleeve 58 with respect to the inner sleeve 55.

The elongated hole 58a is filled with grease, and oil seals 63, 63 are fitted at both ends of the inner peripheral surface of the outer sleeve 58 which is in sliding contact with the outer periphery of the inner sleeve 55,
A cylindrical seal cover 65 is fitted on the outer circumference of the outer sleeve 58 via O-rings 64 at both ends, and the opening surface of the elongated hole 58a is oil-tightly covered by the seal cover 65.

A bent portion 65a is formed at the right end of the seal cover 65 so as to be turned up in the outer peripheral direction.
a is in contact with the movable pulley half 62.

A clutch 70 is provided at the left end of the speed reducer input shaft 45 and the inner sleeve 55.
In the flat outer cylindrical clutch outer 71, the center hole of the bottom wall 71a is fitted to the left end threaded portion of the reduction gear input shaft 45 via the collar 73, and the nut 74 is screwed and tightened. The peripheral side wall 71b is opened to the right.

Inside the clutch outer 71, the left end portion of the inner sleeve 55 integral with the fixed pulley half 61 is
A mounting portion 61b having a slightly reduced diameter and a screw engraved on the outer periphery is formed, a drive plate 72 as a clutch inner is fitted, and a nut 75 is screwed and tightened.

The drive plate 72 is in the shape of a hollow disc, and has a shape in which an inner disc portion 72a is connected to an outer disc portion 72c via a step 72b. Pins 76 are planted on the outer disk portion 72c at equal intervals in the circumferential direction, a clutch shoe 77 is pivotally supported by the pin 76, and is urged toward the center by a clutch spring 78. There is.

The friction member 77a provided on the outer periphery of the clutch shoe 77 is located along the inner peripheral surface of the peripheral side wall 71b of the clutch outer 71, and the clutch shoe 77 pivotally supported by the pin 76 is driven by centrifugal force. When it swings outward in the radial direction against the clutch spring 78, the friction member 77a comes into contact with the inner peripheral surface of the peripheral side wall 71b of the clutch outer 71 to engage the clutch.

Between the drive plate 72 of the clutch 70 and the movable pulley half 62, a spring steel spring 80 is provided around the outer circumference of the seal cover 65 of the outer sleeve 58.
Is interposed. The spring 80 is a compression coil spring, and is formed in an hourglass shape whose diameter gradually decreases from both end portions 80a, 80b to the central portion 80c.
The smallest inner diameter of is equal to the outer diameter of the seal cover 65.

The right end 80a of the spring 80 is fitted into and abutted against the bent concave portion of the bent portion 65a at the right end of the seal cover 65, and the left end 80b is a stepped portion of the drive plate 72.
The movable pulley half 62 is brought into contact with 72b, sandwiched between the movable pulley half 62 and the drive plate 72 and compressed, and the elastic force urges the movable pulley half 62 toward the fixed pulley half 61 side. 80
c is in contact with the outer peripheral surface of the seal cover 65.

In this way, the rear portion of the V-belt 52 having the front portion wound around the drive pulley 40 is sandwiched between the movable pulley half body 62 and the fixed pulley half body 61, which are biased by the spring 80,
The moving pulley half 62 is fixed by the spring 80.
The V-belt 52 is urged toward the 61 side and acts to increase the effective radius of the wound V-belt 52, so that the V-belt 55 can be tensioned.

The continuously variable transmission 23 has the above-mentioned structure, and its operation will be described below. When the rotation speed of the internal combustion engine 21 is low, the centrifugal weight 44 moving along the ramp plate 43 on the drive pulley 40 side is on the center side and the movable pulley half 42 is fixed pulley half as shown by the solid line in FIG. The effective radius of winding the V-belt 52 away from the body 41 is small, and therefore, on the driven pulley 60 side, the movable pulley half body 62 is biased by the spring 80 to approach the fixed pulley half body 61.
The effective radius of the winding of the V-belt 55 is maintained large, and the power is transmitted at a large reduction ratio.

As the engine speed increases, the centrifugal weight 44 moves in the centrifugal direction, as shown by the chain double-dashed line in FIG. 2, and the movable pulley half 42 on the drive pulley 40 side approaches the fixed pulley half 41. The effective radius of winding the V-belt 55 becomes large, so that the movable pulley half 62 separates from the fixed pulley half 61 against the spring 80 on the driven pulley 60 side, and the effective radius of winding the V-belt 55 becomes small. Then, the reduction ratio gradually decreases, and at this time, the clutch 70 is also in the engaged state and the rotational speed of the rear wheel 9 is increased.

A spring 80 for biasing the movable pulley half 62
Has a central portion 80c having a small diameter and both end portions 80a, 80 having a large diameter.
Since the spring 80 itself has a guide function of restricting the eccentricity of the central portion 80c, the central portion 80c is in contact with and supported by the outer periphery of the seal cover 65. The central portion 80c is stably supported even during rotation, and the wavy phenomenon is completely prevented, and a good rotational balance is maintained.

Therefore, the interference of the spring 80 with the clutch shoe 77 and the like due to the loss of the rotational balance is completely avoided, the generation of abnormal noise and the abrasion are prevented, and the durability can be improved.

Since a spring guide is not required as in the prior art, the number of parts is small, the assembling work is easy, the productivity is excellent, and the cost can be reduced. Since the spring 80 is formed in a drum shape whose diameter gradually decreases from both end portions 80a, 80b to the central portion 80c, it has a shape in which the original elastic function of the spring is sufficiently maintained and rotation balance can be easily taken. There is.

Further, since the spring 80 has a structure in which the central portion 80c having a small diameter is in contact with the outer periphery of the seal cover 65 and is in pressure contact with the seal cover 65 from the outside, it is specially designed. The oil tightness can be further ensured so that the grease filled inside the seal cover 65 together with the O-rings 64 at both ends does not leak to the outside without using a member.

[Brief description of drawings]

FIG. 1 is an overall side view of a scooter type motorcycle to which a continuously variable transmission according to an embodiment of the present invention 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 cross-sectional view of a driven pulley and its vicinity.

FIG. 4 is a sectional view of a driven pulley of a conventional continuously variable transmission and its vicinity.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scooter type motorcycle, 2 ... Front part of vehicle body, 3 ... Rear part of vehicle body, 4 ... Floor, 5 ... Body frame, 6 ... Steering handle, 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
... continuously variable transmission, 25 ... unit case, 26 ... left case, 27 ... right case, 28 ... transmission case cover, 29 ... gear case, 30 ... main bearing, 31 ... crankshaft, 32 ... piston, 33 ... connecting rod, 34 ... AC generator, 35 ... Cooling fan, 36 ... Engine cover, 40 ... Driving pulley, 41 ... Fixed pulley half, 42 ... Movable pulley half, 43 ...
Lamp plate, 44 ... Centrifugal weight, 45 ... Reduction gear input shaft, 46 ... Intermediate shaft, 47 ... Rear axle, 48 ... Input gear, 49 ... Intermediate gear, 50 ... Intermediate gear, 51 ... Output gear, 52 ... V belt, 55
… Inner sleeve, 56… Needle bearing, 57… Ball bearing, 58… Outer sleeve, 60… Followed pulley,
61 ... Fixed pulley half body, 62 ... Movable pulley half body, 63 ... Oil seal, 64 ... O-ring, 65 ... Seal cover, 70 ... Clutch, 71 ... Clutch outer, 72 ... Drive plate, 73
… Collar, 74… Nut, 75… Nut, 76… Pin, 77… Clutch shoe, 78… Clutch spring, 80… Spring.

Claims (3)

[Claims] 1. A fixed pulley half body and a movable pulley half body are fitted to an inner cylinder and an outer cylinder, which are slidably fitted to each other and axially supported, respectively, and the fixed pulley half body and the movable pulley half body are joined together. In a continuously variable transmission in which a V-belt is sandwiched between opposed conical surfaces, a spring that is provided around the outer cylinder and presses the movable pulley half toward the fixed pulley half is compared to both ends. A continuously variable transmission characterized in that the diameter of the central portion is small. 2. The continuously variable transmission according to claim 1, wherein the spring has a shape in which a diameter is gradually reduced from both end portions to a central portion. 3. The continuously variable transmission according to claim 1, wherein the spring has a center portion having a small diameter that presses a seal cover covering the outer peripheral surface of the outer cylinder from the outside.