JP2526438Y2 - Pulley structure for V-belt continuously variable transmission - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulley structure for a V-belt type continuously variable transmission in which a face surface and an outer peripheral surface of a boss are extremely strong, light in weight and inexpensive.

[0002]

2. Description of the Related Art Conventionally, a pulley of a V-belt type continuously variable transmission that changes a belt diameter by a rotational driving force and a centrifugal force and changes the belt diameter with the change to transmit power to wheels has been developed. Existing. The pulley in the transmission is composed of a fixed pulley half and a movable pulley half, and the movable pulley half of the pulley slides on a boss of the fixed pulley half, and a space between the fixed pulley halves can be freely adjusted. The power is transmitted by changing the radius of rotation of the V-belt wound between the two pulley halves.

[0003] The pulley half may be formed by welding a ferrous metal face and a boss or by forming a face by casting an aluminum alloy on the ferrous metal boss. ing.

Although it has been theoretically considered to integrate the boss and the face by casting an aluminum alloy in this kind, it has been generally considered that the surface processing is generally performed later and the material of the aluminum alloy is used. From the point
The boss and the face were separate.

[0005]

[Problem to be Solved by the Invention] Since the face and the boss are each formed by processing with an iron-based metal and joined by welding to form a pulley half body, the number of manufacturing steps is large, the number of processing steps is increased, and thus the manufacturing is performed. There were drawbacks that the cost was high and the weight of the device was heavy.

A pulley half having a face formed by casting an aluminum alloy into a boss made of an iron-based metal,
There is a possibility that the boss may run out, and it is necessary to cut the belt engaging surface to maintain the run-out accuracy with the boss.

For this reason, the wear resistance of the surface becomes remarkable,
Since the joint strength with the boss is maintained by the contraction force of the aluminum alloy, it is necessary to secure a large joint area, so that there is a problem that the size of the pulley becomes large and the weight of the device becomes heavy.

Further, since the inner periphery of the boss of the movable pulley slides on the outer periphery of the boss of the fixed pulley half, the boss of the fixed pulley half may have a hard surface. is necessary.

[0009]

Therefore, the inventor of the present invention has made a boss into a fixed pulley half by casting an aluminum alloy with a truncated flat conical face, and chilled the surfaces of the boss and face. Layer, and the boss is formed as a tapered portion whose diameter gradually decreases from the face surface side to the other end along the center line thereof, and a bush made of synthetic resin in which a conical inner periphery corresponding to the tapered portion is formed. And a pulley structure in a V-belt type continuously variable transmission in which a movable pulley half is slidably provided on the bush, so that the face surface is extremely strong and the weight can be reduced. Not only that, the boss portion can be formed in a true cylindrical shape, the strength of the outer peripheral surface can be improved, the material can have excellent wear resistance, and the cost can be reduced. Resolve those were.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

The present invention relates to an improvement in a pulley device for a motor-driven bicycle, a scooter or a motorcycle, and particularly, as shown in FIG. 1, a pulley structure on a driven side.

A fixed pulley half A comprising a pipe-shaped boss 1 and a truncated flat conical face 2 is integrally formed by casting an aluminum alloy.

As shown in FIG. 1, a fixed pulley half A
And the movable pulley half B in combination to form a pulley structure.

As shown in FIG. 2, the fixed pulley half A has a face 2 having a circumferential angle θ of about 150 degrees with respect to the center line G of the boss 1, and protrudes outward from the face 2. And a boss 1. The center line G is formed so as to coincide with the center line of the circumferential angle θ.

The face 2 of the fixed pulley half A is
The chill layer C remains as it is on the casting surface. That is, the chill layer C remains as it is on the casting surface of at least the belt engaging surface 2a of the face 2.

The chill layer C is illustrated in the drawings as having a thickness that is a set of small points (see FIGS. 2 to 4). Specifically, the belt engaging surface 2a of the face 2 is left as it is without casting, and in this case, the chill layer C exists on the surface (FIGS. 2 to 3). (See FIG. 4).

The chill layer C is a rapidly solidified layer formed on the surface of the product when the melt enters the cavity and the heat is rapidly removed from the surface of the mold. When examining the distribution of hardness from the surface to the inside, the hardness is high near the surface, and the hardness rapidly decreases from a certain region. The distance from the surface to the region where the hardness rapidly decreases is defined as the thickness (chill depth) of the chill layer C.

The outer peripheral shape of the boss 1 is provided with a taper so that the diameter gradually decreases from the side of the face 2 toward the other end (the side where the face 2 does not exist) along the center line G. It is formed in a conical shape.

The tapered outer peripheral surface of the boss 1 is referred to as a tapered portion 1a. Specifically, FIG. 2, as shown in FIG. 3, the diameter phi ₁ of the boundary between the face 2 side along the center line G of the boss 1 and the opposite end a face 2 side of the boss 1 (Face 2 there the side that does not exist, shows the other side) as the diameter phi _2, so that the diameter phi _1> diameter phi ₂ become truncated conical boss 1 are formed.

In order to form the boss 1 into a frusto-conical shape, a structure is used in which a draft for the boss 1 is formed in a mold in the step of casting the fixed pulley half A.

The inner surface of the sliding boss 3 of the movable pulley half B is slidable on the boss 1 of the fixed pulley half A, and the face 2 of the fixed pulley half A and the movable face 4 of the movable pulley half B are moved. Are approaching and separating from each other.

A bush 5 made of synthetic resin is interposed around the boss 1 of the fixed pulley half A. The bush 5 is formed as a conical inner periphery so that its inner peripheral surface exactly matches the boss 1, and the outer peripheral surface is formed in a true cylindrical shape. The outer peripheral surface diameter of the bush 5 is determined so that the sliding boss 3 of the movable pulley half B can slide well.

In FIG. 1, reference numeral 6 denotes a driving pulley,
7 is a drive shaft, 8 is a clutch, 9 is a driven shaft, 10 is an axle,
11 is a wheel.

[0024]

In the present invention, a boss 1 and a flattened conical face 2 are integrally formed by casting an aluminum alloy to form a fixed pulley half A, and the surfaces of the boss 1 and the face 2 are respectively formed. Chill layer C and boss 1
Are formed as a tapered portion 1a whose diameter gradually decreases from the face surface 2 side to the other end along the center line G, and a bush 5 made of a synthetic resin having a conical inner periphery corresponding to the tapered portion 1a. And the movable pulley half B is slidably provided on the bush 5 to form a pulley structure in a V-belt type continuously variable transmission. Engagement surface 2a
Secondly, the abrasion resistance of the tapered portion 1a of the boss 1 can be ensured, and secondly, the accuracy of the deflection between the belt engaging surface 2a and the boss 1 can be improved, and the quality can be stabilized. Thirdly, the number of manufacturing steps is reduced, the number of processing steps is reduced, the manufacturing cost can be reduced, and fourthly, effects such as good attachment of the bush 5 can be obtained.

These effects will be described in detail.
Conventionally, since the face and the boss are each formed by forming a ferrous metal and joined by welding to form a pulley half, there are disadvantages in that the number of manufacturing steps is increased, the number of processing steps is increased, and the manufacturing cost is increased. Or, conventionally, the pulley half on the fixed side, in which a face is formed by casting an aluminum alloy into a boss made of an iron-based metal, there is a possibility that the boss may run out, and the belt engaging surface is cut and the It was necessary to keep the runout accuracy of the boss 1 and the flattened conical face 2 by casting aluminum alloy.
And a fixed pulley half A, and its boss 1
And the surface of the face 2 is formed as a chill layer C, and the boss 1 is formed as a tapered portion 1a whose diameter gradually decreases from the face surface 2 side toward the other end along the center line G. In addition to facilitating the moldability of a mold for integrally molding the flat-conical face 2 with the head, the moldability is enhanced, the runout accuracy between the boss 1 and the face 2 can be significantly improved, and the quality can be stabilized. it can.

Further, since the surfaces of the boss 1 and the face 2 of the present invention are formed as chill layers C, the surfaces of the chill layers C are extremely hard, and the wear resistance of the belt engaging surface 2a and the tapered portion 1a is improved. And the bush 5 whose inner peripheral surface matches the tapered portion 1a and whose outer peripheral surface allows the movable pulley half B to slide can be directly mounted on the tapered portion 1a of the boss 1. Since the sliding surface of the movable pulley half A can be set to a predetermined dimensional accuracy without any cutting, the number of manufacturing steps is reduced, the number of processing steps is reduced, and the manufacturing cost can be significantly reduced. There are advantages.

Further, since the engagement surface between the bush 5 and the boss 1 is tapered, mounting can be facilitated.
Further, since the taper fitting can be performed, the bush 5 can be hardly pulled out by the wedge action of the taper. This is because the surface of the tapered portion 1a of the boss 1 is hardened by the chill layer C, so that the bush 5 can more securely bite into the boss 1a and hardly come off.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a motorcycle incorporating the present invention.

FIG. 2 is a sectional view of the fixed pulley half of the present invention.

FIG. 3 is an enlarged sectional view of a main part before processing of FIG. 2;

FIG. 4 is a sectional view in which a movable pulley half is slidably provided on a fixed pulley half.

FIG. 5 is an enlarged sectional view of a main part of FIG. 4;

FIG. 6 is a perspective view showing a bush provided in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Boss 1a ... Taper part 2 ... Face 5 ... Bush A ... Half fixed pulley B ... Half movable pulley C ... Chill layer G ... Center line

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiaki Matsushima 1-2757 Hirosawacho, Kiryu-shi, Gunma Co., Ltd. Inside Yamada Works (72) Inventor Takeo Aoki 1-257-7 Hirosawacho, Kiryu-shi, Gunma Co., Ltd. Yamada Works (56) References JP-A-60-204854 (JP, A) JP-A-59-45349 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] A boss is formed integrally with a frusto-conical flat conical face by casting an aluminum alloy to form a fixed pulley half, and each of the boss and the face is a chill layer, and the boss is a center line thereof. Along the face side
Formed as a tapered portion with a gradually decreasing diameter toward the other end, forming a conical inner circumference that matches the tapered portion
Attach the synthetic resin bush that was
A pulley structure in a V-belt type continuously variable transmission, wherein a movable pulley half is slidably provided .