JPH037825B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic transmission device for a V-belt driven vehicle used in a motorcycle or the like.

In a conventional V-belt driven vehicle transmission, as shown in FIG.
Pulley fixed face 02 and ramp plate 04
are fitted together, and the movable face of the V pulley is 0.
3 can move in the axial direction, but in the circumferential direction, the drive shaft 01
A weight roller 05 is interposed between the movable face 03 and the ramp plate 04, and a fixed face 07 of the V-pulley is integrated with the driven sleeve 06. At the same time, the movable face 08 of the V-pulley is fitted into the driven sleeve 06 so that it can move in the axial direction and rotate together with the driven sleeve 06 in the circumferential direction. is fixed face 0 by the spring force of coil spring 09.
7, and a V-belt 010 is stretched between the faces 02, 03 of the driving side V-pulley and the faces 07, 08 of the driven-side V-pulley.

In addition, in the transmission, the weight roller 0
5 touches movable face 03 and lamp plate 0
4 is formed into a conical surface with a linear generatrix, and when the drive shaft 01 is stopped or rotating at low speed, the weight roller 05 is located closest to the center of the drive shaft 01, Movable face 03
is away from the fixed face 02, the drive side curve radius of the V-belt 010 is small, and the driven side curve radius is large, so the gear ratio is maximum, and the drive shaft 01
As the rotational speed of V-belt 010 increases, the weight roller 05 gradually moves away from the center of the drive shaft 01, the movable face 03 approaches the fixed face 02, and as the radius of curvature on the driving side of the V-belt 010 increases, the radius of curvature on the driven side increases. The gear ratio is becoming smaller and the gear ratio is decreasing.

However, in such a V-belt driven vehicle transmission, if the spring force of the coil spring 09 is weak, the gear shifting action will start at a relatively low engine speed, and when the vehicle reaches a medium speed range, the engine will start to shift. The number of revolutions is insufficient and the transmitted power is insufficient.

In order to eliminate this lack of transmitted power, the spring force of the coil spring 09 is strengthened, and the V-belt 01
0, but in this case, the shift action starts at a relatively high engine speed, so the engine is already rotating at high speed in the low speed range of the vehicle, and the driving force becomes excessive. It's a waste.

To avoid this, when the rotational speed of the drive shaft 01 increases, the weight roller 05 is moved so that the movable face 03 approaches the fixed face 02 by overcoming the large tension of the V-belt 010 due to the reinforcement of the spring force of the coil spring 09. or increase the distance r from the pulley rotation center to the center of the weight roller 05, or increase the inclination angle α of the inclined surface 03a of the movable face 03 and the inclined surface 04a of the ramp plate 04 that are in contact with the weight roller 05. It is necessary to reduce β, in other words, to increase the inclination angle with respect to the axis of the crankshaft.

In other words, as is clear from Fig. 2, the axial force F of the movable face 03 is F = KmrN ² / (tan α + tan β) ... (1) where m is the mass of the weight roller 05, N is the drive shaft rotation speed, and K is the proportional This is clear from the fact that it is a constant.

However, if the weight roller 05 is made heavier, the movable face 03 and ramp plate 04 become larger and the weight of the entire transmission increases, and if the distance r from the pulley rotation center to the center of the weight roller is increased, the movable face 03 and the ramp plate 04 become larger. If the diameters of the face 03 and the ramp plate 04 are increased and one or both of the inclination angles α and β of the inclined surfaces 03a and 04a are decreased, for example, when only α is decreased, as shown in FIG. In this case, the radial movement distance of the weight roller 05 required to bring the movable face 03 closer to the fixed face 02 by Δx increases by Δr, which is the same as when r is increased as described above, and the transmission An increase in overall weight and size was unavoidable.

The present invention relates to an improvement of an automatic transmission device for a V-belt driven vehicle that overcomes these difficulties. A V-belt is wound around a driving pulley and a driven pulley, and centrifugal force acting on a weight installed in the driving pulley causes
The gap between the side surfaces of both pulley faces of the drive pulley widens at low speeds and narrows at high speeds.As the rotational speed of the drive pulley increases, the belt wrapping position on the pulley moves in the radial direction away from the center of rotation of the pulley, and the gear ratio changes. In an automatic transmission system where the
A contact surface that contacts the weight and contributes to adjusting the distance between the side surfaces of both pulley faces is formed in a shape that curves at a steep angle in the axial direction in stages or continuously as it moves from the center of the pulley to the outer periphery. The driven pulley is configured with a torque cam mechanism consisting of a cam groove and a pin that enables the movable face to move in the axial direction as the movable face and the fixed face rotate relative to each other. This feature makes it possible to rationally match engine speed and vehicle speed, and to provide a lightweight and compact transmission for a V-belt driven vehicle despite the fact that it transmits a large amount of power.

An embodiment of the present invention illustrated in FIG. 4 and FIG. 7 will be described below.

1 is a scooter type motorcycle;
At the rear of the swing type power unit 2, the front part of the swing type power unit 2 is pivotally supported via a link 1a to a frame 1b so as to be able to swing up and down, and the rear part is pivotally supported to the frame 1b via a shock absorber 1c.

Further, in the power unit 2, the engine 3 and the transmission case 4 are integrally constructed, and the rear wheels 27 are driven. The crankshaft 5 of the engine 3 is projected to the front inside the transmission case 4.

Further, a ramp plate 6 is integrally fitted to the crankshaft 5, and a drive face collar 7 and a drive fixing face 8 are integrally fitted to the crankshaft 5 by tightening nuts 9.

Furthermore, in the drive face collar 7,
A drive movable face 12 is slidably fitted in the axial direction via a slide collar 11 having an oil reservoir 10, and oil seals 13 are attached to both ends of the slide collar 11, and a radial rib 12b of the drive movable face 12 is fitted. lamp plate 6
The drive movable face 12 can move in the axial direction with respect to the crankshaft 5, but in the circumferential direction, the drive movable face 12 can move relative to the crankshaft 5 through the ramp plate 6. It is designed to be able to rotate together with the shaft 5.

As shown in FIG. 7, the inclined surface 12a of the drive movable face 12 has different inclination angles α ₀ and α ₁ near the center of rotation and near the outer periphery, so that α ₀ <α ₁ , in other words. Then, with respect to the axis of the crankshaft 5, the inclined surface 12a is formed such that the inclined surface near the center of rotation is inclined at a steep angle, and the inclined surface near the outer periphery is inclined at a gentle angle, and the inclined surface 12a and the ramp plate slope are formed. Weight rollers 14 are interposed at regular intervals in the circumferential direction between the surface 6a and the surface 6a.

Incidentally, the inclined surface 12a is smoothly connected by a curved surface having a radius of curvature R larger than the effective radius of the roller 14, as shown in FIG.

Further, a boss 16 is rotatably fitted to a driven shaft 15 which is rotatably supported at the rear of the transmission case 4, and a driven fixed face 1 is fitted to the boss 16.
7 are fitted together.

Further, a driven cam 18 is loosely fitted to the boss 16, a driven movable face 19 is fitted integrally to the driven cam 18, and a pin 20 is fitted to the boss 16 passing through a cam groove 18a provided in the driven cam 18. The driven cam groove 18a and the pin 20 constitute a torque cam mechanism that allows the movable face to move in the axial direction as the movable face and the fixed face rotate relative to each other. It is adapted to be moved in the axial direction and the circumferential direction relative to the boss 16 while being guided by the groove 18a.

Furthermore, a clutch inner plate 22 is integrally fitted to the boss 16 with a nut 29, a compression coil spring 21 is interposed between the driven movable face 19 and the clutch inner plate 22, and a centrifugal clutch 23 is mounted on the clutch inner plate 22. A clutch outer 24, which is movably pivoted and formed to surround the centrifugal clutch 23, is integrally fitted to the driven shaft 15 with a nut 30.

Further, the driven shaft 15 is a reduction gear device 25.
The rear wheel 27 is connected to the rear wheel 26 via the rear wheel 26, and the rear wheel 27 is integrally attached to the rear wheel 26.

Since the embodiment shown in FIGS. 4 to 7 is configured as described above, when the engine 3 is stopped, the spring force of the compression coil spring 21 causes the driven movable face 19 to move from the driven fixed face 17. The drive movable face 12 is pressed against the drive fixed face so that the winding radius of the V-belt 28 wrapped around the driven pulley is maximized, and the winding radius of the V-belt 28 wrapped around the drive pulley is minimized. 8, the weight roller 14 is held between the central outer circumferential surface 12c of the movable drive face 12, the inclined surface 12a, and the ramp plate inclined surface 6a, and as a result, the speed ratio is set to the maximum.

Next, when the engine 3 starts, the driven fixed face 17 and the driven movable face 19 rotate at the maximum gear ratio as the engine speed N _increases .
In the following conditions, the centrifugal clutch 23 and the clutch outer 24 are separated and the clutch is in a disconnected state, so the driven shaft 15 remains in a stopped state and the scooter type motorcycle 1 remains stationary.

When the rotation speed N of the engine 3 increases and reaches N ₁ (point O in Figure 9), the centrifugal clutch 2
3 and clutch outer 24 have started,
The driven shaft 15 starts rotating, and the scooter type motorcycle 1 starts moving.

After the scooter-type motorcycle 1 starts moving (part A in FIG. 9), the engine 3 continues to rotate at a substantially constant rotation speed _N1 , and power is transmitted from the centrifugal clutch 23 to the driven shaft 15 via the clutch outer 24. The scooter type motorcycle 1 accelerates in a half-clutch state.

Furthermore, when the clutch consisting of the centrifugal clutch 23 and the clutch outer 24 is completely connected (section B in FIG. 9), the weight roller 14 comes into contact with the outer peripheral surface 12c of the center part of the drive movable face, and the pin 2
0 remains at the inclined portion 18b of the driven cam groove 18a, the vehicle speed increases as the engine rotational speed N increases at the maximum gear ratio.

Furthermore, when the engine speed N reaches _N2 (Fig. 9, part c), the axial force exerted on the drive movable face 12 by the V-belt 28, which is tensioned by the spring force of the compression coil spring 21, and the driven cam groove. The axial force due to the centrifugal force acting on the weight roller 14 exceeds the sum of the axial force acting on the pin 20 engaged with the inclined portion 18b of the weight roller 18a, and the weight roller 14 moves along the inclined surface 12a of _α1 . As the pin 20 moves outward, the pin 20 enters the driven cam groove 1.
8a toward the curved portion 18c, the gear ratio decreases and the vehicle speed increases while the engine speed N remains substantially constant.

Furthermore, the weight roller 14 has an inclination angle α ₁ ,
When the pin 20 is located at the corner of the inclined movable face 12a with a changed angle of α ₂ and at the curved portion 18c of the driven cam groove 18a (section D in FIG. 9), the intermediate gear is shifted while maintaining that position. As the engine speed N increases, the vehicle speed further increases.

When the engine speed N reaches N ₃ (part E in Figure 9), the axial force exerted on the drive movable face 12 by the V-belt 28, which is tensioned by the spring force of the compression coil spring 21, is reduced by the weight. The axial force due to the centrifugal force acting on the roller 14 exceeds the weight roller 14, and the weight roller 14 moves outward along the inclined surface 12a of _α2 , and the pin 20 moves the axial portion 18d of the driven cam groove 18a toward its end. The gear ratio decreases and the vehicle speed increases while the engine speed N remains substantially constant.

Finally, when the weight roller 14 comes into contact with the inner circumferential surface of the outer cylindrical portion of the drive movable face 12 (FIG. 9, section F), the winding radius of the V-belt 28 is fixed, and the minimum gear ratio is set. At the minimum gear ratio, the vehicle speed further increases as the engine speed N increases.

This movable face inclined surface 12 with a large inclination angle α ₂
When the weight roller 14 is in contact with a, the large inclination angle α ₂ increases the axial movement distance Δx of the drive movable face 12 even if the radial movement distance Δr of the weight roller 14 is relatively small. Therefore, even if the radius of the drive movable face 12 is small, the degree of change in the gear ratio can be increased.

Further, when the weight roller 14 is in a state of moving onto the movable face inclined surface 12a having _a larger inclination angle _α2 than the small inclination angle α1, as shown in FIG.
Since the pin 20 on the driven pulley side is set to be located at the curved part 18c of the driven cam groove 18a, the tension applied to the belt is further reduced, and the distance between the driven fixed face 17 and the driven movable face 19 is further increased. This can be done easily and the reduction of the gear ratio can be carried out even more smoothly.

In this way, in the embodiment described above, the winding radius of the V-belt 28 wound around the drive pulley is made as large as possible except when the vehicle is stopped or at extremely low speeds, thereby reducing power loss due to bending deformation of the V-belt 28. In addition, the life of the V-belt 28 can be extended.

By appropriately changing the position of the slope changing corner of the movable face slope 12a, the values of the slope angles α ₁ and α ₂ , and the position of the curved portion 18c of the driven cam groove 18a, the characteristics of the automatic transmission can be freely changed. can do.

Furthermore, instead of forming the movable face inclined surface 12a into two conical angles with different inclination angles, it may be formed into a curved surface with a continuously changing inclination angle.

In the present invention, as described above, a V-belt is wound around the driving pulley and the driven pulley, and due to the centrifugal force acting on the weight built into the driving pulley, the gap between the sides of both pulley faces of the driving pulley is widened in the low speed state and wide in the high speed state. In an automatic transmission device, the belt winding position of the drive pulley moves in a radial direction away from the rotation center of the pulley as the rotational speed of the drive pulley increases, and the gear ratio automatically decreases. A contact surface that contributes to adjusting the distance between the side surfaces of both pulley faces is formed into a shape that curves at a steep angle in the axial direction in stages or continuously as it moves from the center of the pulley to the outer periphery, thereby maintaining the gear ratio. Since the drive pulley rotates at a low speed and the centrifugal force applied to the weight (mrN ² of the numerator of equation (1) in the specification of the present invention) is small, the inclination angle α of the outer surface of the movable face becomes α ₁ . small and said
The tanα of the numerator in equation (1) also becomes smaller, and the drive pulley rotates at a low speed and centrifugal force is applied to the weight (as described above).
In the region where the numerator of equation (1) is large, the angle of inclination of the outer surface of the movable face increases to α ₂ , which corresponds to the increase in the numerator of equation (1), and the denominator of equation (1) increases. tanα is also increased, and therefore there is a function of stably maintaining an intermediate gear ratio in a portion where the inclination angle of the outer surface of the movable face changes.

Further, in the present invention, the driven pulley includes:
A torque cam mechanism consisting of a driven cam groove and a pin that enables the movable face to move in the axial direction as the movable face and the fixed face rotate relative to each other is configured, so the gear ratio can be adjusted from a large value in response to changes in load torque. When changing to a small value or from a small value to a large value, the speed ratio can be smoothly changed.

Furthermore, in the present invention, in order to achieve the above-described effects, at a relatively low vehicle speed at the initial stage of starting, the engine speed is increased at the maximum gear ratio,
After accelerating the vehicle, it is possible to perform the first automatic gear shift that gradually increases the gear ratio while keeping the engine speed at a relatively low speed, so that the engine's driving power is not wasted. The vehicle can be sufficiently accelerated without any changes, and then the engine speed can be increased at the intermediate gear ratio compared to the maximum speed ratio to further accelerate the vehicle, and then the engine speed can be increased relatively. It is possible to carry out the second automatic gear shift, which gradually increases the gear ratio, while the engine is still running at a high engine speed, so it is possible to compare the engine revolution speed with that in the first automatic gear shift range. It is possible to increase the vehicle driving force and improve the acceleration performance in a high-speed range, and it is possible to rationally match the engine rotational speed and the vehicle speed to obtain excellent running performance.

Therefore, in the present invention, large power can be transmitted efficiently despite being small and lightweight.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional plan view of a conventional V-belt transmission type automatic transmission, Fig. 2 is an explanatory diagram illustrating the relationship between the centrifugal force acting on the weight roller and the axial force acting on the movable face in the same transmission, and Fig. FIG. 3 is an explanatory diagram illustrating the change in size of the movable face when the inclination angle of the movable face is changed in the same transmission, and FIG. FIG. 5 is a longitudinal sectional plan view illustrating the same embodiment, FIG. 6 is a cutaway plan view of the essential parts, and FIG. 7 is an enlarged vertical sectional plan view of the essential parts of FIG. 5. 8 is an enlarged vertical sectional plan view of the main part of the embodiment, and FIG. 9 is a characteristic diagram illustrating the speed change operation of the embodiment. 1... Scooter type motorcycle, 2... Power unit, 3... Two-cycle gasoline engine, 4
...Transmission case, 5...Crankshaft, 6...
... Lamp plate, 7 ... Drive face collar, 8 ... Drive fixed face, 9 ... Nut, 10 ... Oil reservoir, 11 ... Slide collar, 12 ... Drive movable face, 13 ... Oil seal, 14 ... ...Weight roller, 15...
Driven shaft, 16... Boss, 17... Driven fixed face, 18... Driven cam, 19
...Driven movable face, 20...Pin, 21
... Compression coil spring, 22 ... Clutch inner plate, 23 ... Centrifugal clutch shoe,
24...Clutch outer, 25...Reduction gear device, 26...Rear axle, 27...Rear wheel, 28...
V-belt.

Claims (1)

[Claims] 1 A V-belt is wrapped around the drive pulley and the driven pulley, and due to the centrifugal force acting on the weight built into the drive pulley, the gap between the sides of both pulley faces of the drive pulley increases at low speeds and narrows at high speeds, causing the rotation of the drive pulley. In an automatic transmission in which the belt winding position of the pulley moves in a radial direction away from the rotation center of the pulley as the number of pulleys increases, and the gear ratio automatically decreases, the distance between the sides of the pulley face in contact with the weight. The contact surface that contributes to adjustment,
The pulley is formed into a shape that is gradually or continuously curved at a steep angle in the axial direction as it moves from the center to the outer periphery to constitute a gear ratio holding means, and the driven pulley has a movable face and a fixed shape. 1. An automatic transmission device for a V-belt driven vehicle, comprising a torque cam mechanism consisting of a cam groove and a pin that enables the movable face to move in the axial direction as it rotates relative to the face.