JPH0680341B2 - V-belt type automatic transmission - Google Patents

Description

TECHNICAL FIELD The present invention relates to a V-belt type automatic transmission used for motorcycles, snow vehicles, and the like.

[Conventional technology]

The V-belt type automatic transmission has a V-belt stretched between a driving pulley and a driven pulley, and the driving pulley and the driven pulley are fixed pulleys fixed to a rotary shaft. The plate includes a plate and a movable pulley plate that faces the fixed pulley plate and forms a belt groove, and is movable back and forth in the axial direction. Then, the movable pulley plate of the drive-side pulley is pushed by the centrifugal force of the weight that is in contact with the back surface and the peripheral wall of the movable pulley plate and rotates along with the drive-side pulley, so that the engagement radius of the V-belt and the pulley is increased. Is configured to be continuously changed.

In particular, this V-belt type automatic transmission is widely used for proximity, scooters, family motorcycles, practical motorcycles, snow vehicles, etc. because it has a stepless and smooth gear ratio and has a simple structure. It is used.

By the way, in this type of V-belt type automatic transmission, the weight is constantly sliding in accordance with the change in the number of revolutions of the rotary shaft to perform the gear shift, so that the weight is worn. Therefore, as disclosed in Japanese Utility Model Laid-Open No. 55-152900, a grease reservoir is formed on the back side of the movable pulley plate, and a lubricant such as grease slides on the back side of the movable pulley plate. It is designed to suppress wear at the time.

[Problems to be solved by the invention]

However, in the conventional V-belt type automatic transmission of this type, since the cover for preventing the lubricant from scattering is attached, the space in which the weight is housed becomes hot without touching the outside air, and the V-belt and There was a problem that the life of the weight was shortened. As a result, the number of times the V belt is replaced tends to increase.

[Means for solving problems]

The present invention has been made in view of the above circumstances, and provides a V-belt type automatic transmission in which the life of members such as a V-belt can be extended. The V-belt type automatic transmission according to the present invention includes a cylindrical weight adjusting member and an outer peripheral portion of the weight adjusting member that engages with the movable pulley plate and pushes the movable pulley plate by centrifugal force due to rotation of the pulley. And a weight accommodating space formed between the cam member and the movable pulley plate, between the cam member holding the weight and the movable pulley plate. It is provided with a communicating gap. Here, the material having self-lubricating property means, for example, a porous material impregnated with lubricating oil, a fiber reinforced resin mixed with a lubricating material, or the like.

[Action]

In the present invention, the weight and the movable pulley plate are cooled by exposing the cam member to the outside and allowing the external air to flow from the gap between the cam member and the movable pulley plate into the weight storage space.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view showing a main part of a V-belt type automatic transmission according to the present invention, and FIG. 2 is a sectional view showing a unit swing type engine such as a scooter in which the V-belt type automatic transmission according to the present invention is implemented. In the drawings, the reference numeral 1 in these drawings indicates a unit swing type engine. Since the engine 1 functions as one component of a suspension device for suspending the rear wheels 2, it swings up and down on the rear portion of the vehicle body (not shown). It is pivotally supported.

The unit swing type engine 1 is an engine body 3
A power transmission mechanism 6 for transmitting the power of the engine body 3 to the rear wheel pulley shaft 5 via the crankshaft 4, and a rear wheel shaft connected to a speed reducer 7 for reducing the rotation of the rear wheel pulley shaft 5. 8 and 8 are integrally held by a transmission case 9.

Reference numeral 10 denotes a V-belt type automatic transmission that constitutes the power transmission mechanism 6 together with a centrifugal clutch 11. The V-belt type automatic transmission 10 is rotatable with a crank side pulley 12 supported by a crank shaft 4 as a rotating shaft. The rear wheel side pulley 14 supported on the rear wheel side pulley shaft 5 via the collar 13 and the V belt 15 spanned between these pulleys. The rotation of the crankshaft 4 is passed through the centrifugal clutch 11. It is transmitted to the rear wheel pulley shaft 5. The rotation of the rear wheel pulley shaft 5 is further reduced by the speed reducer 7 and then transmitted to the rear wheel shaft 8.

The crank side pulley 12 and the rear wheel side pulley 14 are fixed pulley plates 12a and 14a fixed to the crank shaft 4 and the collar 13, respectively, and fixed pulley plates 12a and 14a.
And a movable pulley plate 12b, 14b that forms a belt groove facing each other and is movable back and forth in the axial direction. The fixed pulley plate 12a and the movable pulley plate 12b of the crank side pulley 12 are made of, for example, an aluminum material, an iron material, a stainless steel material, or the like in an umbrella shape. In the embodiment, an aluminum die-cast product is used.
The movable pulley plate 12b has an outer peripheral edge integrally formed with a peripheral wall protruding rearward in the axial direction.

Reference numeral 16 denotes a weight, which is formed in a cylindrical shape as shown in an enlarged vertical cross section in FIG. 3 and is in contact with the cam surface formed on the back surface of the movable pulley plate 12b and the inner surface of the peripheral wall.
Reference numeral 17 denotes a cam member which is located behind the movable pulley plate 12b and fixed to the crankshaft 4, and the cam member 17 is formed of a pressed material such as a steel plate in an umbrella shape.
A weight 16 is held between the movable pulley plate 12b and the movable pulley plate 12b so that the weight 16 can slide and roll in the radial direction. In other words, the weight 16 is housed in the weight housing space S formed between the movable pulley plate 12b and the cam member 17, and is in contact with both cam surfaces of the movable pulley plate 12b and the cam member 17. These cam surfaces extend in the radial direction, and the facing distance thereof changes the meshing radius with the V-belt 15 by pushing the movable pulley plate 12b by the centrifugal force of the weight 16 accompanying the rotation of the crank side pulley 12. As described above, the width is gradually narrowed in the outer diameter direction. That is, the cam surface of the movable pulley plate 12b is formed so as to gradually bulge rearward.

The weight 16 is composed of a cylindrical body made of a metal material, the weight adjusting member 18 capable of changing the weight by changing the hole diameter of the hollow portion, and a self-lubricating material 16a covering the outer peripheral portion of the weight adjusting member 18. It is formed from and. The weight of the weight 16 is set so that a centrifugal force that pushes the movable pulley plate 12b can be obtained when the crankshaft 4 reaches a predetermined rotation speed. As the material 16a having the self-lubricating property, for example, a porous material impregnated with a lubricating oil or a fiber reinforced resin mixed with a lubricating material can be used.

In detail, the resin in this case is nylon resin, polyacetal resin (POM), polytetrafluoroethylene resin (PTFE), polybutylene terephthal resin (PBT),
Polypropylene resin (PP), polyethylene resin (PE),
Alternatively, it may be a phenol resin or the like. The fiber is glass fiber, carbon fiber, or aramid fiber (for example, Kevlar fiber manufactured by DuPont). The lubricant is a solid lubricant such as polytetrafluoroethylene resin (PTFE), graphite, molybdenum disulfide (MoS ₂ ) or a fluid lubricant such as mineral oil. However, the above PTFE is not used when the base material is PTFE.

The outer diameter of the cam member 17 is smaller than the inner diameter of the peripheral wall of the movable pulley plate 12b, and the weight storage space S is provided between the outer peripheral edge of the cam member 17 and the inner peripheral edge of the movable pulley plate 12b. There is provided a gap g that communicates with the outside of the crank side pulley 12. The gap g is set so that the cam member 17 and the movable pulley plate 12b are separated from each other in the axial direction and are maximized at the time of the top shown by the chain line in FIG.

Reference numeral 19 is a guide member which is interposed between the movable pulley plate 12b and the cam member 17 and which guides the cam member 17.

In the V-belt type automatic transmission configured as described above, the weight 16 for pushing the movable pulley plate 12b by the centrifugal force is provided with the weight adjusting member 18 and the self-lubricating property of covering the outer peripheral portion of the weight adjusting member 18. Since it is formed of the material 16a, the wear can be suppressed without supplying a lubricant such as grease. Therefore, unlike the conventional case, it is not necessary to attach a cover for preventing the lubricant from scattering, and the cam member 17 can be exposed to the outside of the crank side pulley 12. Further, between the outer peripheral edge of the cam member 17 and the inner peripheral edge of the movable pulley plate 12b, the weight accommodating space S accommodating the weight 16 is provided with a gap g for communicating with the outside of the crank side pulley 12. From g, external air can be circulated in the weight storage space S.

Therefore, the outside air can be brought into contact with the weight 16 and the back surface of the movable pulley plate 12b, so that the heat of these members can be transferred to the outside air to be cooled and prevented from reaching a high temperature. At this time, the heat of the V belt 15 is transferred to the cooled movable pulley plate 12b,
The belt 15 will also be cooled at the same time. In other words,
The heat of the V-belt 15 is transmitted to the outside air via the movable pulley plate 12b. Further, since the gap g is set to be maximum at the top, it is possible to maximize the flow rate of the outside air at the top when the heat generation amount of the V-belt 15 and the like is maximum.

FIG. 4 is a cross-sectional view of an essential part showing another embodiment according to the present invention, in which the same or equivalent members as those shown in FIG. 1 are designated by the same reference numerals and the description thereof is omitted. In this embodiment, the outer peripheral edge of the cam member 17 is integrally provided with a cover 20 that covers the peripheral wall of the movable pulley plate 12b from the outside when stopped or at low speed. By doing so, it is possible to reduce dust and the like from entering the inside when the apparatus is stopped.

〔The invention's effect〕

As described above, according to the present invention, the weight that is in contact with the movable pulley plate and that pushes the movable pulley plate by the centrifugal force accompanying the rotation of the pulley covers the cylindrical weight adjusting member and the outer peripheral portion of the weight adjusting member. The exposed cam member and the movable pulley plate are formed of a self-lubricating material, and a gap is provided between the cam member for holding the weight and the movable pulley plate so as to communicate the weight storage space to the outside. External air can be circulated into the weight storage space through the gap between the weight and the movable pulley plate by the outside air.

Therefore, it is possible to prevent the members such as the V-belt from being heated to a high temperature, so that the service life can be extended. As a result, it is possible to reduce the number of times the V-belt or the like needs to be replaced, and it is expected that maintenance and inspection will be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a V-belt type automatic transmission according to the present invention, and FIG. 2 is a sectional view showing a unit swing type engine such as a scooter in which the V-belt type automatic transmission according to the present invention is implemented. FIG. 3 and FIG. 3 are vertical cross-sectional views showing enlarged weights, and FIG. 4 is a cross-sectional view of a main part showing another embodiment according to the present invention. 1 …… Unit swing type engine, 4 …… Crank shaft, 5 …… Rear wheel side pulley shaft, 10 …… V-belt type automatic transmission, 12 …… Crank side pulley, 12a …… Fixed pulley plate, 12b …… Movable pulley plate, 15 ... V belt, 1
6 …… weight, 17 …… cam member.

Claims (1)

[Claims] 1. A pulley having a fixed pulley plate fixed to a rotary shaft, and a movable pulley plate facing the fixed pulley plate and forming a belt groove so as to be movable back and forth in the axial direction, a rear surface of the movable pulley plate, and A V-belt type automatic transmission comprising a weight that is in contact with a peripheral wall and pushes a movable pulley plate by a centrifugal force generated by rotation of a pulley, and a cam member that holds the weight between the movable pulley plate and the movable pulley plate. Is formed of a cylindrical weight adjusting member and a self-lubricating material that covers the outer peripheral portion of the weight adjusting member, and the cam member and the movable pulley plate are provided between the cam member and the movable pulley plate. A V-belt type automatic transmission having a gap for communicating a weight storage space formed therebetween to the outside.