JPS61165058A - Manufacture of weight for v-belt type automatic transmission - Google Patents

Abstract

PURPOSE:To produce a weight having good roundness by employing a tubular weight then providing a disc gate extending in circumferential direction on the innercircumference at one open end and infecting fiber reinforced resin. CONSTITUTION:In order to produce a weight 8, a metal die 12 and a weight adjusting member 9 are machined to hold said member 9 at the inside of a cavity 13 formed in the metal die 12 then inject fiber reinforced resin into said cavity 13. Nylon resin, polyacetal resin, polytetra-fluoroethylene, etc. is employed as the base material resin while glass fiber, carbon fiber, etc. is employed as the filler fiber. Upon injection of fused fiber reinforced resin through a runner 17, it is distributed uniformly in all directions because it is positioned in the center of a disc gate 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing weights for V-belt automatic transmissions used in motorcycles, snowmobiles, and the like.

[Conventional technology]

A V-belt type automatic transmission is one in which a V-belt is passed between a driving pulley and a driven pulley, and each of the driving pulley and driven pulley is a It has a pulley plate and a movable pulley plate which forms a belt groove opposite to the fixed pulley plate and is movable back and forth in the axial direction. Then, by pushing the movable pulley plate of the driving pulley by the centrifugal force of a weight that engages with the back surface and peripheral wall of the movable pulley plate and rotates with the driving pulley, the engagement radius between the V belt and the pulley is increased. is configured to change continuously.

In particular, this V-belt type automatic transmission has been widely used in scooters, family bikes, practical bikes, snowmobiles, etc. in recent years because it can provide a stepless and smooth gear ratio and has a simple structure. It is used.

By the way, the weight of this type of transmission constantly pushes the movable pulley plate to change the engagement radius with the V-belt in response to fluctuations in the rotational speed of the rotating shaft. move smoothly, and
It is necessary not to wear out the movable pulley plate. Therefore, conventional weights have generally been made of resin into a cylindrical shape, and are manufactured by injecting resin through a single edge gate provided on the outer peripheral surface of the weight.

[Problem that the invention seeks to solve]

However, such a manufacturing method has a problem in that the roundness of the weight cannot be obtained when the weight is molded from fiber-reinforced resin. This is because the orientation of the fibers filled in the resin is different from other parts in the weld part where the two tips of the resin flowing in different directions in the cavity collide, and the molding shrinkage rate in this weld part is different from that in other parts. This is thought to be due to the difference. As a result, the weld part protrudes,
This is a cause of uneven wear because smooth transfers cannot be achieved.

[Means for solving problems]

The present invention was made in view of the above circumstances, and provides a method for manufacturing weights for V-belt type automatic transmissions, which allows weights with good roundness to be manufactured from fiber-reinforced resin. The method for manufacturing a weight according to the present invention is to form the weight into a cylindrical shape, provide a disc-shaped gate on the inner periphery of one open end of the weight, and inject fiber-reinforced resin from the center of the gate.

[Effect]

In the present invention, by injecting the fiber-reinforced resin from the periphery in the axial direction, the influence of the orientation of the filled fibers on the molding shrinkage rate is reduced.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a mold used in the method of manufacturing weights according to the present invention, FIG. 2 is a cross-sectional view taken along the line nn of FIG. 1, and FIG. 1 is a sectional view showing the main parts of a V-belt type automatic transmission equipped with a weight, and in these figures, the reference numeral 1 indicates a unit swing type engine such as a scooter. This engine 1 includes an engine main body 2 disposed at the front, a rear wheel shaft (not shown) disposed at the rear and connected to a rear wheel pulley shaft via a reduction gear, and the power of the engine main body 2 is transferred to a crankshaft 3. A V-belt automatic transmission 4 transmitting power from the rear wheel to the rear wheel pulley shaft via a centrifugal clutch is held together by a transmission case 5, and functions as a component of a suspension system that suspends the rear wheel.

The V-belt type automatic transmission 4 includes a crank pulley 6 supported on the crankshaft 3, a rear wheel pulley rotatably supported on the rear wheel pulley shaft via a collar, and a The hook is made up of the handed belt 7, etc.

The crank-side pulley 6 includes a fixed pulley plate 6a fixed to the crankshaft 3, and a fixed pulley plate 6a fixed to the crankshaft 3.
It has a movable pulley plate 6b which forms a belt groove opposite to a and is movable back and forth in the axial direction.

Reference numeral 8 denotes a weight, which is formed into a cylindrical shape as shown in an enlarged longitudinal section in FIG. 4, and has a cylindrical weight adjusting member 9 made of a metal material such as iron or brass inside. A cam member 10 is located on the back side of the movable pulley plate 6b and is fixed on the crankshaft 3. Said weight 8
is interposed between the movable pulley plate 6b and the cam member 10, and is held between the cam surfaces of both members so as to be slidable and movable in the radial direction. The cam surfaces have opposing intervals in the outer radial direction so that the centrifugal force of the weight 8 accompanying the rotation of the crank pulley 6 pushes the movable pulley plate 6b and changes the radius of engagement with the belt 7. It is formed to become gradually narrower.

11 is interposed between the movable pulley plate 6b and the cam member 10, and is connected to the movable pulley plate 6 with respect to the cam member 10.
This is a guide member that guides b.

Note that the dashed line in FIG. 3 shows the state of the V-belt type automatic transmission 4 at the top.

When manufacturing the weight 8 of the V-belt type automatic transmission described above, first, the mold 12 and the weight adjustment member 9 are processed,
After the weight adjustment member 9 is held inside a cavity 13 formed in the mold 12, fiber reinforced resin is injected into the cavity 13.

To explain this manufacturing method in detail, first, the lower mold 12a
and the upper mold 12b are processed to form a cylindrical cavity 13 between these members, and a metal material is processed to form the weight adjustment member 9 into a cylindrical shape. Then, the weight adjustment member 9 is inserted into the protrusion 14 of the lower mold 12a and held inside the cavity 13. Here, the weight adjustment member 9 is formed to have a shorter length in the axial direction than the cavity 13, and is held in a state in which the outer surface is surrounded by the cavity 13 by the stepped portion 15.

Next, after injecting the molten fiber-reinforced resin into the cavity 13 from the runner 17 at the center of the gate 16, the weight 8 is formed in the cavity 13 by cooling and solidifying the resin. The gate 16 is connected to the upper mold 1
2b is slightly spaced apart from the upper end surface of the protrusion 14 to form a disk shape, and is communicated with the runner 17 in the center. That is, the weight 8 is formed in a cylindrical shape, and the gate 16 is provided so as to extend in the circumferential direction at a portion forming an inner peripheral edge 8a of one open end of the weight 8.

The base material of the fiber reinforced resin to be injected is nylon resin,
Polyacecool resin (POM), polytetrafluoroethylene resin (PTFE), polybutylene terephthalate resin (PBT), polypropylene resin (PP)
, polyethylene resin (PE), or phenolic resin.

It is considered to be polyimide resin, etc. As for the fibers to be filled,
Glass fiber, carbon fiber, or aramid fiber (for example, Kepler fiber manufactured by DuPont) is used. In addition, the fiber reinforced resin includes polytetrafluoroethylene resin (PTFE), graphite, molybdenum disulfide (MoSt).
) or other solid lubricants may be mixed. However, the above P
TFE is not used when the base material is PTFE.

In the method for manufacturing a weight for a V-belt automatic transmission configured as described above, when molten fiber-reinforced resin is injected from the runner 17, the runner 17 is located at the center of the disc-shaped gate 16. Therefore, the resin is dispersed so that the flow rate is approximately equal in all directions. The dispersed resin flows into the cavity 13 from the inner peripheral edge 8a of one open end of the weight 8 through the gate 16, flows in the axial direction, and fills the cavity 13. Thereafter, when the resin is cooled and solidified, the resin is formed into a shape corresponding to the cavity 13, so that the weight 8 can be manufactured.

Therefore, when injecting the resin, it is possible to keep the flow direction constant and prevent the weld portion from occurring as in the conventional case. Therefore, the molding shrinkage rate of the entire weight 8 can be made substantially equal, and the influence of the orientation of the filled fibers on the molding shrinkage rate can be reduced. this is,
This is thought to be because by keeping the flow direction of the resin constant, the orientation of the filled fibers becomes equal.

In the above embodiment, an example was described in which the weight adjustment member 9 was insert-molded when the weight 8 was molded, but it can also be fixed by press-fitting or the like after molding.

〔Effect of the invention〕

As explained above, according to the present invention, the weight is formed into a cylindrical shape, and a disc-shaped gate is provided on the inner periphery of one open end of the weight, and fiber-reinforced resin is injected from the center of this gate. By making the resin flow direction constant in the axial direction, molding shrinkage can be made substantially equal throughout.

Therefore, since the influence of the filled fibers on the molding shrinkage rate can be reduced, weights with good roundness can be manufactured from fiber-reinforced resin.

As a result, it is possible to smoothly transfer the weights and reduce uneven wear, so it is expected that the life will be extended.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a mold used in the method for manufacturing weights according to the present invention, FIG. 2 is a sectional view taken along the line ■-n in FIG. 1,
FIG. 3 is a sectional view showing the main parts of a V-belt type automatic transmission equipped with weights in which the method according to the present invention is implemented;
The figure is a vertical sectional view showing an enlarged weight. 4... V-belt type automatic transmission, 6a... Fixed pulley plate, 6b... Movable pulley plate, 8...
... Weight, 8a ... Inner peripheral edge, 9 ... Weight adjustment member, 10 ... Cam member, 12a ... Lower mold, 12b ... Upper mold, 13. ...Cavity, 16... -Gate.

Claims (1)

[Claims] A method for manufacturing a weight of a V-belt type automatic transmission comprising a weight interposed between a cam member and a movable pulley plate that faces a fixed pulley plate and forms a belt groove, the weight being formed into a cylindrical shape. A weight for a V-belt type automatic transmission is manufactured by forming a weight into a shape, and providing a disc-shaped gate extending in the circumferential direction on the inner periphery of one opening end, and injecting fiber-reinforced resin from the center of the gate. Method.