JP3193274B2 - Weight roller for V-belt type automatic 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 weight roller mounted on a V-belt type automatic transmission used for a scooter type motorcycle, a snowmobile, and the like.

[0002]

2. Description of the Related Art In a general V-belt type automatic transmission, a V-belt is wound around a driving pulley and a driven pulley, and the winding diameter of the V-belt around both pulleys is changed steplessly in accordance with the rotation speed. This is a structure that obtains an optimal gear ratio. Specifically, both pulleys are configured by a combination of a fixed pulley plate fixed to the rotating shaft, and a movable pulley plate disposed to face the fixed pulley plate and provided to be able to advance and retreat with respect to the fixed pulley plate. I have. On the rear side of the movable pulley plate of the drive pulley, a cam plate is fixedly mounted on a fixed shaft, and a weight roller is sandwiched between these plates. When the drive pulley rotates, the weight roller moves to the outer peripheral side of the drive pulley along the cam surface formed on the cam plate and the movable pulley plate by centrifugal force, and pushes the movable pulley plate toward the fixed pulley plate. As a result, the diameter of the V belt wound around the drive pulley changes, and at the same time, the diameter of the V belt wound around the driven pulley also changes.

The above-mentioned weight roller is usually mainly composed of a metal cylinder having a predetermined weight, and slides constantly against a movable pulley plate or a cam plate made of metal. For this reason, contact between metals may cause problems such as mutual abrasion and scratching, and may increase the sliding resistance. Therefore, in a conventional weight roller, a resin-coated surface layer is formed on the outer peripheral surface of a cylindrical roller body made of metal. As the resin, aliphatic polyamide resin, so-called aliphatic nylon, is widely used. Carbon fiber is mixed into this resin as a reinforcing material, and polytetrafluoroethylene resin (PTFE) is mixed into the resin as a solid lubricant. The aim was to improve the wear resistance of the weight roller and reduce the friction coefficient and sliding resistance.

[0004]

In the above-mentioned weight roller, the surface layer is required to have heat resistance, abrasion resistance and stability of friction coefficient so that a constant speed change characteristic can be obtained for a long period of time. However, in the surface layer using the aliphatic polyamide resin as described above, the heat resistance may be insufficient in some cases, the wear resistance at high temperatures is not sufficient, and the stability of the friction coefficient against temperature change and aging change. Sometimes lacked.

The present invention has been made in view of the above circumstances, and is a weight roller for a V-belt type automatic transmission having excellent heat resistance, sufficient wear resistance even at high temperatures, and a stable friction coefficient. It is intended to provide.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and has been described in claim 1.
A weight roller for a belt-type automatic transmission is provided with a movable pulley plate which is provided to be able to advance and retreat with respect to a fixed pulley plate fixed to a rotating shaft to form a belt groove of a V-belt, and a rear side of the movable pulley plate. Disposed and clamped between a cam plate fixed to the rotating shaft,
A weight roller for a V-belt type automatic transmission, wherein the movable pulley plate is pushed to the fixed pulley plate side to change the diameter of the belt wound around the pulley by centrifugal force caused by rotation of a pulley composed of both pulley plates. A metal roller main body on a cylinder, and a resin surface layer formed to cover the outer peripheral surface of the roller main body. The surface layer is made of potassium titanate as a reinforcing material and a lubricant.
It is characterized by being formed of an aromatic polyamide resin mixed with wax .

According to a second aspect of the present invention, there is provided a weight roller for a V-belt type automatic transmission, wherein the aromatic polyamide resin is used.
Is 65% of the whole, potassium titanate is 30%, wax
Occupies 5%.

[0008]

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. (1) Configuration of One Embodiment FIG. 1 shows a swing type power unit mounted on a scooter type motorcycle or the like. The power unit includes an engine 1, a V-belt type automatic transmission 2 for transmitting the power of the engine 1 to a rear wheel 3, and a centrifugal clutch (not shown) interposed between the automatic transmission 2 and the rear wheel 3. And a unit case 4 that covers and holds the automatic transmission 2, the centrifugal clutch, and the speed reduction mechanism.

The engine 1 includes a cylinder 5, a piston 6 slidably fitted in the cylinder 5, a crankshaft (rotating shaft) 8 connected to the piston 6 via a connecting rod 7, A crankcase 9 for rotatably supporting the crankshaft 8. The automatic transmission 2 is connected to one end of the crankshaft 8.

The automatic transmission 2 has a drive pulley 10 supported on a crankshaft 8 and a driven shaft (not shown) connected to an axle of the rear wheel 3 via a centrifugal clutch and a speed reduction mechanism. The vehicle includes a driven pulley, and a V-belt 11 wound around a driving pulley 10 and a driven pulley. The driving pulley 10 includes a fixed pulley plate 20, a movable pulley plate 30 that is disposed opposite to the fixed pulley plate 20 to form the belt groove 12 of the V-belt 11, and a cam disposed on the back side of the movable pulley plate 30. Plate 4
0, and a weight roller 50 sandwiched between the movable pulley plate 30 and the cam plate 40.

As shown in FIG. 2, the fixed pulley plate 2
0 is fixed to the crankshaft 8 and the movable pulley plate 3
Numeral 0 is provided so as to be able to advance and retreat in the axial direction of the crankshaft 8 with respect to the fixed pulley plate 20. These pulley plates 20, 30 are formed in an umbrella shape by aluminum die casting or the like. 1 and 2, the movable pulley plate 30 is shown on the upper side in an initial state farthest from the fixed pulley plate 20, and on the lower side in an operation end state closest to the fixed pulley plate 20.

As shown in FIG. 3, the movable pulley plate 3
On the outer surface side facing the 0 cam plate 40, a plurality of guides 31 parallel to the crankshaft 8 are formed in the circumferential direction.
The cam plate 40 is, for example, formed by pressing steel into an umbrella shape and is fixed to the crankshaft 8. A plurality of sliders 41 are attached to the peripheral portion of the cam plate 40 in the circumferential direction corresponding to the guides 31, and the movable pulley plate 30
Of the movable pulley plate 3
The rotation of the movable pulley plate 30 with respect to the fixed pulley plate 20 is guided together with the rotation of the cam pulley 0 integrally with the cam plate 40. On the opposing surfaces of the movable pulley plate 30 and the cam plate 40, cam surfaces 32 gradually approaching toward the outer peripheral direction,
The weight roller 50 is sandwiched in a state where the outer peripheral surface is in contact with the cam surfaces 32 and 42. Further, guide walls 33 are formed on both sides of the cam surface of the movable pulley plate 30 to guide the radial movement of the weight roller 50 across the peripheral edge of the weight roller 50.

As shown in FIG. 4, the weight roller 50 has a cylindrical roller body 51 and a roller body 51.
And a resin surface layer portion 52 that covers the outer peripheral surface. The roller body 51 is made of a metal such as brass or iron. On the other hand, the surface layer portion 52 is mainly composed of an aromatic polyamide resin, and a reinforcing material such as a fiber-based or granular material and a lubricant such as a liquid-based or solid-based lubricant are mixed in the polyamide resin in appropriate amounts. ing. Surface layer 52
Is formed with a cover portion 53 that covers the end face from the peripheral edge portions on both sides of the roller body 51, and the cover portion 53 comes into sliding contact with the guide wall 33.

The aromatic polyamide resin is a polyamide resin having a benzene nucleus (also referred to as a benzene ring) introduced into a main chain, unlike an aliphatic polyamide resin.

Specifically, as the semi-aromatic polyamide resin, a polyphthalamide resin (PPA) represented by the following formula, a modified polyamide 6T resin (PA6T),

Embedded image Alternatively, a polymeta-xylene adipamide resin (PA-MXD6) represented by the following formula is used.

Embedded image These polyamide resins show the basic structure of semi-aromatic polyamide resin, but may be wholly aromatic polyamide resin. An aramid resin or the like is used as the wholly aromatic polyamide resin.

As the fibrous reinforcing material, glass fiber,
Organic fibers such as carbon fibers and aramid fibers, ceramic fibers, and metal fibers are used. In addition to the above, needle-shaped crystals, so-called whiskers, are particularly effective as the fibrous reinforcing material. As the whiskers, potassium titanate, alumina, silicon carbide, silicon nitride, aluminum borate and the like are used. Further, as the granular reinforcing material, glass beads, calcium carbonate, aluminum hydroxide, mica and the like are used.

As the liquid lubricant, oils and fats, liquid wax and the like are used. As a solid lubricant, polytetrafluoroethylene resin (PTF) is used.
E), molybdenum disulfide (MoS ₂ ), graphite, solid wax such as olefin resin, olefin resin and the like are used. However, when the roller body 51 is made of polytetrafluoroethylene resin (PTFE), it is not used as a lubricant.

(2) Operation of One Embodiment Next, the operation of the automatic transmission 2 will be described. a. Basic Operation When the engine 1 is operated, that is, when the piston 6 in the cylinder 5 reciprocates and the crankshaft 8 rotates, the drive pulley 10 rotates integrally with the crankshaft 8, and the rotation of the drive pulley 10 11, transmitted to the rear wheel 3 via a driven pulley, a centrifugal clutch, and a reduction mechanism. Here, in response to the rotation of the drive pulley 10, the weight roller 50 causes the movable pulley plate 30 and the cam plate 4 to move by centrifugal force.
Rolls or slides on the 0 cam surfaces 32 and 42 to move to the outer peripheral side. The weight roller 50 moving between the cam surfaces 32 and 42 pushes the movable pulley plate 30 toward the fixed pulley plate 20 in this manner. Accordingly, the diameter of the V belt 11 wound around the driving pulley 10 changes, and at the same time, the diameter of the V belt 11 wound around the driven pulley also changes. That is, the diameter of the V-belt 11 wound around the drive pulley 10 is small at the time of low-speed rotation and large at the time of high-speed rotation.

B. Operation of Weight Roller 50 In the weight roller 50 of the above-described embodiment, the surface layer 52 on the outer peripheral surface has the movable pulley plate 30 and the cam plate 40.
The movable pulley plate 30 is continuously rolled or slid with respect to the cam surfaces 32, 42 to push the movable pulley plate 30. The surface layer 52 is
As described above, since it is mainly composed of an aromatic polyamide resin, heat resistance is particularly improved as compared with an aliphatic polyamide resin. Therefore, it has sufficient wear resistance even at high temperatures. Further, the coefficient of friction is stable over temperature and over time, and the coefficient of friction is low.

Further, since the above-mentioned reinforcing material is mixed into the polyamide resin, the strength is further improved.
In particular, the whisker of potassium titanate or the like has a length and a diameter of several tenths smaller than that of a fibrous reinforcing material such as carbon fiber. Since it can be sufficiently and uniformly dispersed and mixed into the portion 53, the wear resistance is further improved and there is no uneven wear. Furthermore, since the above-mentioned lubricant is mixed in the polyamide resin of the surface layer portion 52, the friction coefficient of the surface layer portion 52 is greatly reduced, and thus a smooth operation with very little sliding resistance is realized.

As described above, the surface layer 52 of the weight roller 50 has high wear resistance even at high temperatures, and its frictional resistance is greatly reduced and stable. Constant shifting characteristics can be obtained over a long period of time, and the performance of the entire power unit can be maintained over a long period of time.

[0023]

Next, an experiment based on the present invention and a friction coefficient and an abrasion degree of a comparative example which is a conventional material were tested, and both were compared. The composition ratio (%) is% by weight. (Example) Resin-polyphthalamide resin (PPA): aromatic polyamide resin about 65% Reinforcing material-whisker: potassium titanate 30% lubricant-wax about 5%. However, the content may be 5 to 20%, and the same effect is exhibited within this range. (Comparative Example) Resin-nylon 46 (PA46): 80% aliphatic polyamide resin Reinforcing material-10% carbon fiber Lubricating material-solid lubricant: 10% polytetrafluoroethylene resin (PTFE)

FIG. 5 shows a test result of a specific wear amount (wear resistance) according to a temperature change, and FIG. 6 shows a test result of a temporal change of a friction coefficient. With respect to the specific wear caused by the temperature change, the example according to the present invention is low and almost constant from low temperature to high temperature, whereas the comparative example mainly composed of the aliphatic polyamide resin increases with increasing temperature. And the abrasion resistance is remarkably deteriorated. With respect to the coefficient of friction, the examples according to the present invention are low and constant, whereas the comparative examples mainly composed of aliphatic polyamide resin are high as compared with the resin of the present invention, and increase rapidly after a certain period of time. After that, it declined again, but it has been higher than the initial value.

As is apparent from the above, the aromatic polyamide resin according to the present invention exhibits high abrasion resistance even at high temperatures, has a significantly reduced friction coefficient, and has stability. It is very suitable as a material forming the surface layer of the weight roller of the belt type automatic transmission.

Although the above-described embodiment exemplifies a V-belt type automatic transmission incorporated in a swing type power unit mounted on a scooter type motorcycle or the like, the present invention is not limited to such a power unit. The present invention can be applied to a V-belt type automatic transmission provided in another power mechanism such as a snowmobile.

As described above, the V-belt type of the present invention
According to the weight roller for the automatic transmission, the outer peripheral surface is formed.
The surface layer is made of potassium titanate, a reinforcing material, and a lubricant.
Aromatic polyamide resin mixed with certain wax
Because it is formed, sufficient heat resistance even at high temperatures,
It has abrasion resistance and a small coefficient of friction. Therefore, the operation of pushing the movable pulley plate is stabilized, and the shift characteristics of the V-belt type automatic transmission can be maintained for a long time with the initial setting.

[0028]

[0029]

[Brief description of the drawings]

FIG. 1 is a partial plan view of a V-belt type automatic transmission according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a rear view of a movable pulley plate.

FIG. 4 is a cross-sectional view of a weight roller according to one embodiment.

FIG. 5 is a graph showing a test result of abrasion resistance according to a temperature change in an example.

FIG. 6 is a graph showing a test result of a friction coefficient of an example.

[Explanation of symbols]

 2 V-belt type automatic transmission 8 Crankshaft (rotating shaft) 10 Drive pulley 11 V-belt 12 Belt groove 20 Fixed pulley plate 30 Movable pulley plate 40 Cam plate 50 Weight roller 51 Roller body 52 Surface layer portion

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-174199 (JP, A) JP-A-5-332411 (JP, A) JP-A-5-203004 (JP, A) JP-A 8- 14346 (JP, A) Japanese Utility Model 63-184256 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 9/00-9/26

Claims (2)

(57) [Claims] 1. A movable pulley plate which is provided so as to be able to advance and retreat with respect to a fixed pulley plate fixed to a rotating shaft to form a belt groove of a V-belt, is provided on a back side of the movable pulley plate, and The movable pulley plate is pushed to the fixed pulley plate side by a centrifugal force caused by the rotation of the pulley composed of the two pulley plates and is held between the cam plate fixed to the rotation shaft and the belt with respect to the pulley. A weight roller for a V-belt type automatic transmission for changing a winding diameter of a metal roller main body on a cylinder, and a resin surface layer formed to cover an outer peripheral surface of the roller main body; The part consists of potassium titanate , a reinforcing material, and a lubricant
A weight roller for a V-belt type automatic transmission, which is formed of an aromatic polyamide resin mixed with wax . 2. The method according to claim 1, wherein the aromatic polyamide resin comprises 65
%, Potassium titanate 30%, wax 5%
The weight row for a V-belt type automatic transmission according to claim 1.
La.