JPH0239664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to a drive system for an engined vehicle, and more particularly to a drive system for a vehicle with a predetermined minimum engine speed and a second engine speed.
The present invention relates to a V-belt transmission capable of continuously changing the transmission ratio between a predetermined high engine speed and a predetermined high engine speed.

Generally, in snowmobiles and the like, when the engine is coupled to the driven member using a V-belt, this coupling is performed by a pair of variable speed pulleys, namely a primary pulley coupled to the engine and the member to be driven. This is done by a coupled secondary pulley and a V-belt interconnecting said pulleys. The secondary pulleys are typically spring loaded and torque sensitive to maintain constant belt tension, and the primary pulleys typically vary their effective belt diameter to adjust the effective diameter of the pulleys. It is configured to vary the diameter ratio and thus also the drive ratio between the engine and the driven member.

Utility Model Publication No. 56-42529 (same as U.S. Pat. No. 4,027,544) discloses a stationary pulley fixed to the drive shaft of an engine, and a device for changing the distance from the fixed pulley, that is, the stationary pulley. A primary clutch variable speed pulley system is described having a sliding sheave that is free to move axially along the drive shaft. A coil spring is used to normally bias the sliding sheave away from the fixed sheave. An endless V-belt surrounds the drive shaft and is disposed between the fixed and sliding sheaves and extends around a secondary or driven pulley. A set of cam-like flyweights cooperates with the sheave and abuts rollers held in a fixed axial position relative to the drive shaft. As engine speed increases, centrifugal force causes the cam flyweights to move outwardly toward the stationary rollers, which propel the sliding sheave toward the stationary sheave.

The V-belt clutch device shown in Utility Model Publication No. 56-42529 is sufficiently effective in providing the desired drive characteristics as the engine speed and load change, but the cam-shaped flyweight and attached It has been observed that excessive wear occurs due to the rotating contact between the cam follower roller and the cam follower roller. Also, the length of the flyweights required to obtain the desired force to propel the sliding sheave towards the fixed sheave against the force of the coil springs limits the diameter of the springs that can be used. It is therefore necessary to use high stress springs to obtain the necessary force balance. The use of such high stress springs results in undesirable changes in spring rate over a limited period of use.

Accordingly, it is an object of the present invention to provide a V-belt transmission that does not use cams and does not require the use of high force springs to avoid wear.

In order to achieve this objective, according to the present invention,
a drive shaft; a stationary sheave member coaxial with the drive shaft; a stationary sheave member concentrically fixed to the shaft; movable sheave means supported by said shaft extension including a sliding sheave movable to change the spacing between said sheave and said stationary sheave; and between said sliding sheave and said stationary sheave; a V-belt supported on the shaft extension, a drive member fixed to the shaft extension and including means for engaging the slide sheave to rotate the slide sheave therewith; flyweight linkage means movably coupled along the extension and operative to urge the sliding cable towards the stationary cable as the drive member rotates, the flyweight linkage means comprising:
a first link means pivotally connected to the drive member at one end, a second link means pivotally connected to the sliding sheave at one end; means for rotatably interconnecting the other ends, wherein pivoting of both link means changes the position of the sliding sheave relative to the drive member, and at least one of the first link means and the second link means A flyweight is provided on one side, and when the sliding rover is furthest away from the stationary rover,
The center of mass of the flyweight is disposed at a position substantially equal to the position of the one pivot point of the link means having the flyweight when viewed in the longitudinal direction of the drive shaft, and As seen, there is provided a V-belt transmission characterized in that the flyweighted link means is disposed inside the pivot point of the link means.

In FIG. 1, a shaft 20 having an axle 22
is adapted to be driven by an engine (not shown). The end of the shaft 20 has an external tapered portion 24
The stationary pulley member 26 has an internal tapered portion 28 for joining. Member 26 has a stationary sheave 30 and a shaft extension 32. bolt 3
4 fixes the member 26 to the shaft 20. The cylindrical extension 32 has a first cylindrical portion 36, a shoulder 38, a reduced diameter threaded portion 40, and a further reduced diameter cylindrical portion 42, all of which are coaxial with the shaft 20. .

The cylindrical portion 36 of the extension body 32 is connected to the movable sheave means 4
4, the means having a drive member or spider 46, a sliding sheave 48, a compression spring 50, and a cap 52 connected to the sheave 48 by a fixture 54. Drive member or spider 46
has an internal thread 56 and is adapted to be secured on the screw 40 opposite a washer 57 which engages the shoulder 38 of the extension 32. The sliding cable 48 is the first
a bearing 58 for slidingly engaging portion 36 of extension 32 between a first position shown in the figure and a second position shown in FIG.
The positions correspond to the positions of the V-belt 60 at the minimum and maximum radius from the axis 22. Cap 52 similarly includes a bearing 62 for sliding engagement with portion 42 of shaft extension 32.

At a selected angular position about axis 22,
The pulley 48 has a plurality of spaced pairs of fingers 64, one pair of which is shown in FIG.
Of these pairs, parallel spaced pairs of fingers extend generally parallel to axis 22. A leg 66 of the spider 46 extends radially between the pair of fingers 64, and a contact button 68 made of a suitable material serves as a sliding bearing between the pair of fingers 64 and the spider leg 66. ing. This structure prevents rotation of the sheave 48 and cap 52 about the shaft 22 relative to the spider or drive member 46. Spring 50 acts on cap 52 to elastically displace it and sheave 48 away from stationary sheave 30 and into engagement with washer 57.

At other selected angular positions about axis 22, sheave 48 has link pivots 70, one of which is shown in FIG. These pivots extend generally perpendicular to axis 22 and are oriented tangent to concentric circles about this axis. At each pivot 70, a flyweight linkage assembly 72 connects the pulley 48 to a pivot 74 on the spider 46. The linkage 72 includes a first link member 76 having a first end pivotally connected to the pivot 74 and a second link member 76 having a first end pivotally connected to the pivot pin 70.
The link member 78 is provided. The free end of link 76 is connected to the free end of link 78 by a pivot pin 80. Between pivots 70 and 80, link 78 supports a flyweight 82, and link 76 has an angular extension with a flyweight 84 attached thereto.

It has been appreciated that link members 76 and 78 may be constructed from lightweight aluminum or from a suitable plastic material, with the center of mass of the linkage assembly being determined by the relative position of flyweights 82 and 84. . Additionally, the linkage assembly does not have sliding or frictional contact such as exists between conventional cams and cam followers, and therefore has relatively long durability.

The linkage system and associated flyweights are arranged between the spider 46 and the movable sheave 48 in such a way that they do not intrude into the cavity for receiving the spring member 50 in either the closed or open position. placed in between. Therefore, the design is not limited to the use of high stress type springs.

Next, the operation will be explained.

When in use, connect the V-belt 60 to the tugs 30 and 4.
8 and attached to a mechanism driven by the engine of the shaft 20 and having tapered sheaves springing toward each other; (not shown). The spring 50 pushes the pulley 48 away from the pulley 30 and the belt 60
has its minimum radius about axis 22, as shown in FIG. When in this position, the clutch is said to be "disengaged."

When the engine throttle is opened, shaft 2
0, the pulley 30, shaft extension 32, and drive member or spider 46 begin to rotate at high speed;
Legs 66 engage fingers 64 to rotate sheave 48 and cap 52 in the same manner. spider 4
The centrifugal force due to the rotation of 6 acts on the flyweight 84 to rotate the first link 76 counterclockwise around the pivot 74, and also acts on the flyweight 82 to rotate the second link 78 counterclockwise around the pivot 70. Rotate it. As the engine speed increases, these centrifugal joint effects cause links 76 and 78 to move toward the position shown in FIG. Once this occurs, the sliding sheave assembly 44 moves toward the stationary sheave 30, thereby first stopping the V-belt from slipping and then forcing the V-belt 60 radially outward relative to the shaft 22. .

When the device reaches a stable state, the forces acting on the links cause the sliding sheave 48 to change the radius relative to the belt 60 squeezed between the sheaves 30 and 48 at a given rotational speed of the sheave 48. It is therefore also positioned to provide a radius that will produce the desired velocity for the member driven by belt 60. Engine speed vs. drive ratio characteristics are determined by appropriate selection of the spring rate for spring 50, the lengths of links 76 and 78, and the location of the center of mass of flyweights 82 and 84 relative to the link pivots. This device is a single unit and only one
It can be attached to and detached from the shaft 20 by manipulating two stators or bolts 34.

The present invention provides a long-life V-belt transmission that does not use cams or require the use of high force springs. According to the present invention, due to the characteristic flyweight linkage means and the specific arrangement of the flyweights in the linkage means, when the rotational speed of the drive shaft is low, that is, when the engine rotational speed is low, the centrifugal force due to the flyweight is reduced. The force is so small that there is no force to move the sliding sheaves, and this ensures that the sheaves are separated, that is, the clutches are disengaged, and the clamping of the sheaves to the V-belt is reduced. The pressure remains low.

Furthermore, when the engine speed gradually increases and the drive shaft speed starts to rise gradually, the characteristic flyweight linkage means of the device according to the invention and the particular arrangement of the flyweights in the linkage means allow The centrifugal force due to the fly weights also begins to rise smoothly, ensuring a smooth transition from the disengaged state to the engaged state of the clutch, thus ensuring a long life of the V-belt, and the transmission device according to the invention. When used in a vehicle, the ride comfort is extremely stable even when changing gears, and does not cause discomfort to passengers.

The present invention has been described in detail to provide those skilled in the art with the information necessary to apply the novel principles of the invention and to make and use such specialized components as desired. However, the invention can also be implemented with parts and devices of slightly different shape from those described above, and various modifications may be made to the details of the parts without departing from the scope of the invention. It is possible to do so.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of the primary pulley according to the present invention when it is in the low gear ratio mode, FIG. 2 is a vertical cross-sectional view of the primary pulley when it is in the high gear ratio mode, and FIG.
The figure is a cross-sectional view taken along line 3--3 in FIG. 2 to show details of the flyweight linkage. 20... Drive shaft, 26... Stationary rover member, 30... Stationary rover, 32... Shaft extension body, 44... Movable rover means, 46... Spider (drive member), 48... Sliding rope Car, 50... Compression spring, 52... Cap, 70, 74, 80... Pivot, 72... Flyweight linkage assembly, 76, 78... First and second link, 82,
84...Fly weight.

Claims (1)

[Scope of Claims] 1 (a) a drive shaft; (b) a stationary sheave member including a stationary sheave and a shaft extension coaxial with said drive shaft and concentrically fixed to said shaft; (c) a sliding sheave juxtaposed to the stationary sheave and movable axially along the shaft extension to vary the spacing between the stationary sheave and supported by the shaft extension; (d) a V-belt supported between said sliding sheave and said stationary sheave; (e) fixed to said shaft extension and engaged with said sliding sheave; a drive member including means for causing the slide sheave to rotate therewith; (f) movably coupling the slide sheave along a shaft extension relative to the drive member, and when the drive member rotates; (g) a first link means, the flyweight linkage means being pivotally connected to the drive member at one end; a second link means pivotally connected to the slide pulley at one end; and means rotatably interconnecting the other ends of the first and second link means; pivoting of the link means changes the position of the sliding cable relative to the drive member; (h) at least one of the first linking means and the second linking means is provided with a flyweight; (i) the sliding cable When the car is furthest away from the stationary sheave, the center of mass of the flyweight is at a position substantially equal to the position of the one pivot point of the link means having the flyweight, when viewed in the longitudinal direction of the drive shaft. A V-belt transmission, characterized in that the V-belt transmission is located inside the pivot point of the flyweighted link means when viewed in the radial direction of the shaft extension. 2. The device according to claim 1, wherein the sliding sheave is between the stationary sheave and the drive member. 3. Apparatus according to claim 1, wherein the first link means is pivotally connected to the drive member about an axis perpendicular to the axis of the drive shaft. 4. Apparatus according to claim 1, wherein the second link means is pivotally connected to the sliding cable about an axis perpendicular to the axis of the drive shaft. 5. Apparatus according to claim 1, wherein the linkage means is pivotally connected to the drive member and to the sliding sheave about an axis perpendicular to the axis of the drive shaft. 6. The device of claim 1, wherein the flyweights are provided between pivot points at both ends of the first link means and between pivot points at both ends of the second link means. 7. Apparatus according to claim 1, further comprising spring means for urging the sliding sheave axially along the shaft extension in a direction away from the stationary sheave.