JPS6344601Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fixed face mounting structure in a belt type automatic transmission.

Belt-type automatic transmissions are already known that use a drive belt mainly made of rubber and pulleys with variable pitch diameters, and that automatically change the reduction ratio according to the engine speed.

The above-mentioned belt type automatic transmission has a simple structure and is capable of continuously variable speed, so it is often adopted especially for models such as two-wheeled vehicles that are required to be small, inexpensive, and have a wide range of rotation zones.

As is well known, in such automatic transmissions, the structure uses the frictional resistance between the belt and the pulley to transmit power, so there is no friction between the pulley and the rotating shaft to which the pulley is attached. A torsional moment is generated depending on the resistance. Further, the pulley is composed of a fixed face and a movable face in order to make the pitch diameter variable, but since the movable face slides in the axial direction of the rotating shaft, a thrust load acts on the fixed face as a reaction force. .
Therefore, the pulley, especially the fixed face, must be firmly attached to its rotating shaft.

FIG. 1 is a diagram showing an example of a conventional mounting structure of a pulley to a rotating shaft in an automatic transmission.
2 is an engine case, 2 is a side cover, 3 is a crankshaft of the engine, 4 is a drive pulley that is attached to the crankshaft 3 and consists of a fixed face 5 and a movable face 6, and 7 is a drive belt. The movable face 6 is fitted onto the outer periphery of a boss collar 8 fitted onto the crankshaft 3 so as to be freely slidable in the axial direction.
is fixed to the end surface 8a of the boss collar 8 by a nut 9 which is fitted onto the shaft end of the crankshaft 3 and screwed onto the shaft end via a washer 9a.

By the way, in such a mounting structure, the fixed face 5 is formed of a non-ferrous metal with good heat dissipation, such as aluminum, in order to cope with frictional heat with the belt 6;
The fixed face 5 is softer than the boss collar 8 because the boss collar 8 which is in direct surface contact with the boss collar 8 is made of a highly rigid metal. In addition, due to the outer circumferential diameter and wall thickness of the boss collar 8, the area where the fixed face 5 makes direct surface contact with the end surface 8a of the boss collar 8 is also small. Therefore, from these points, when the above-mentioned torsional moment or thrust load acts on the fixed face 5, the boss collar 8
There is a risk that "galling" or "looseness" may occur at the contact portion with the end surface 8a. In addition, fixed face 5
The same applies to the contact portion with the washer 9a. This is a major inconvenience when attempting to increase the transmitted torque as the engine output increases.

The present invention was developed in consideration of the above points, and includes a fixed face and a movable face that constitute a pulley with a variable pitch diameter, which are attached to a rotating shaft, and the fixed face is made of non-ferrous metal. The movable face is slidably mounted on a boss collar externally fitted on the rotating shaft, and the fixed face is a tightening member screwed onto the end face of the boss collar and onto the rotating shaft. In the belt-type automatic transmission that is fixed by pressure, the boss collar is formed of a metal with higher rigidity than the fixed face, and thrust washers having a larger diameter than the boss collar are provided on both sides of the fixed face. It is characterized by intervening,
The belt type allows the fixed face to be stably and firmly attached to the rotating shaft by eliminating the causes of galling or loosening of the fixed face, making it possible to increase the transmitted torque in line with higher engine output. The object of the present invention is to provide a mounting structure for a fixed face in an automatic transmission.

Hereinafter, the present invention will be explained based on an embodiment shown in the drawings.

2 and 3 are a sectional view and a schematic side view of the main parts of a belt type automatic transmission to which the present invention is applied, and in these figures, 10 is an engine case, and 11 is a side opening of the engine case 10. 12 is a crankshaft (rotating shaft) of an engine 13. On the side cover 11 side of the crankshaft 12, there is a drive pulley 14 with a centrifugal variable diameter structure, and on a driven shaft (none of which is shown) that transmits rotation to the rear wheel, there is a driven pulley 15 with a variable diameter structure. are attached to each pulley, and a drive belt 16 having a V-belt structure mainly made of rubber is wound between these pulleys 14 and 15.

The drive pulley 14 is composed of a movable face 17 and a fixed face 18 made of, for example, aluminum with good thermal conductivity. The fixed face 18 is slidably inserted into the shaft of the crankshaft 12, and the fixed face 18 is held between thrust washers 20 and 21, which are arranged in surface contact with both sides of the base of the fixed face 18, respectively. The boss collar 19 is pressed and fixed to the end face 19a of the boss collar 19 by a tightening member 23 such as a nut that is fitted into the end and screwed onto the shaft end. Both thrust washers 2
0 and 21 are made of a metal with higher rigidity than the fixed face 18, and both thrust washers 2
0 and 21 both have the same outer diameter and the boss collar 1
It is formed to have a larger diameter than 9.

A lamp plate 24 is attached to the movable face 17.
A weight roller 25 is interposed between the ramp plate 24 and the movable face 17. The distance between the opposing surfaces of the lamp plate 24 and the movable face 17 is formed to become gradually narrower toward the outer circumference thereof.
When the weight roller 25 moves outward under the influence of centrifugal force, the movable face 17 slides toward the fixed face 18 to a position that balances the centrifugal force.
Therefore, the effective radius around which the belt 16 is wound around the drive pulley 14 becomes larger. The sliding range of the movable face 17 is restricted by a tapered collar 26 fitted into the outer periphery of the base side of the crankshaft 12.

A large number of straight fins 18a constituting a cooling fan are formed on the outer surface of the fixed face 18 at equal intervals in the circumferential direction, and furthermore, on the outer side of these fins 18a, there are provided a plurality of straight fins 18a constituting a cooling fan. Side fins 18b forming air passages a between the fins 18b and the outer surface are integrally formed with the fins 18a.

Further, the side cover 11 is formed with a bulging portion 11a in which a portion corresponding to the fixed face 18 is swollen outward, and a cold air for introducing low-temperature outside air into the bulging portion 11a. Inlet port 11b
is formed, and furthermore, a guide plate 11c is attached to the side fin 1 of the fixed face 18 from the front part of the side cover 11.
The guide plate 11c extends close to the outer surface of the bulging portion 11a, thereby forming a cool air introduction path 11d to the fan between the guide plate 11c and the inner surface of the bulged portion 11a. Further, a plate-shaped gasket 27 is provided at the joint between the side cover 11 and the engine case 10, and has the function of partitioning the transmission chamber into the side cover side and the engine case side. In addition, 28 is an outside air introduction pipe, and 29 is an exhaust port.

Next, the operation of the present invention will be explained below.

When the crankshaft 12 rotates, due to the frictional resistance between the drive pulley 14 and the drive belt 16, the fixed face 18 and the crankshaft 12
A torsional moment is generated between the two. moreover,
Since the movable face 17 receives the centrifugal force of the weight roller 25 and slides toward the fixed face 18, a thrust load also acts on the fixed face 18. These torsional moments and thrust loads are concentrated at the attachment part of the fixed face 18 to the crankshaft 12, but the fixed face 18 in this embodiment has both sides of its root part attached to thrust washers 20 and 21. Since it is attached to the crankshaft 12 in a pinched manner, it can sufficiently withstand these torsional moments and thrust loads, and the fixed face 18 will not be galled or loosened. That is, the thrust washers 2 are attached to both sides of the base of the fixed face 18.
0 and 21 are in surface contact with each other, and both thrust washers 20 and 21 are connected to the boss collar 19.
Since the fixed face 18 is formed to have a larger diameter, the contact area of the fixed face 18 with the thrust washers 20, 21 is large, and therefore the torsional moment and thrust load are distributed accordingly. In other words, the thrust washers 20 and 21 function to disperse stress due to torsional moments and thrust loads that are concentrated on both sides of the attachment portion of the fixed face 18 to the crankshaft 12, particularly at the root portion.
Further, since the thrust washers 20 and 21 are both formed to have the same outer diameter and have equal contact areas with the fixed face 18 on the left and right sides, they also function to transmit the stress uniformly to the fixed face 18 on the left and right sides.
Therefore, stress is not partially concentrated on the contact surface of the fixed face 18 with the thrust washers 20, 21. From the above points, the causes of galling or loosening of the fixed face 18, which is relatively soft, have been fundamentally eliminated, and the fixed face 18 has been completely removed.
8 to the crankshaft 12 becomes stable and strong, and as a result, it is possible to eliminate inconveniences when attempting to increase the transmission torque of the drive pulley 14 as the output of the engine increases.

As detailed above, the present invention has a fixed face and a movable face that constitute a pulley with a variable pitch diameter, which are attached to a rotating shaft, and
the fixed face is formed of non-ferrous metal;
The movable face is slidably mounted on a boss collar externally fitted on the rotating shaft, and the fixed face is fixed to the end face of the boss collar by pressure contact with a tightening member that is screwed onto the rotating shaft. In the belt-type automatic transmission, the boss collar is formed of a metal with higher rigidity than the fixed face, and thrust washers having a larger diameter than the boss collar are interposed on both sides of the fixed face. Because of the structure, the thrust washer reduces the surface pressure in the thrust direction, allowing the fixed face to be stably and firmly attached to the rotating shaft, thereby increasing the transmitted torque in line with the high output of the engine. It has excellent effects such as:

[Brief explanation of the drawing]

Fig. 1 is a partially omitted sectional view showing an example of a conventional mounting structure, Figs. 2 and 3 show an embodiment of the present invention, Fig. 2 is a sectional view of the main part, and Fig. 3 is a sectional view of the main part. It is a partially omitted schematic side view. 12...Crankshaft (rotating shaft), 14...
...Drive pulley, 17...Movable face, 18
... Fixed face, 19 ... Boss collar, 20,
21... Thrust washer, 23... Tightening member.

Claims (1)

[Scope of utility model registration request] A fixed face and a movable face constituting a pulley with a variable pitch diameter are attached to a rotating shaft, the fixed face is made of non-ferrous metal, and the movable face is attached to a boss collar fitted onto the rotating shaft. It is slidably attached to the top of the
In a belt type automatic transmission in which the fixed face is fixed to an end face of the boss collar by pressure contact with a tightening member screwed onto the rotating shaft, the boss collar is made of a metal having higher rigidity than the fixed face. 1. A mounting structure for a fixed face in a belt-type automatic transmission, characterized in that the fixed face is formed by a thrust washer having a larger diameter than the boss collar on both sides of the fixed face.