JPH11257447A - V-belt type automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a V-belt type automatic transmission to reduce a load exerted on a torque pin without increasing a cost. SOLUTION: In a V-belt type automatic transmission having a V-belt 26 spanning between a drive pulley and a driven pulley 23, a torque cam pin 41 is arranged at a sleeve-form fixing face boss 30 at which one of the driven pulleys 23 is fixed. A torque cam groove 42 with which a torque cam pin 41 is engaged in a slide contact manner is formed in a sleeve-form moving face boss 32 which is arranged on the outer peripheral surface of the fixing face boss 30 and at which the other of the driven pulleys 23 is fixed. A spacer 43 is interposed at a slide contact part between the torque cam pin 41 and the torque cam groove 42. A slope 44 is formed at a slide contact part between the spacer 43 and the torque cam groove 42, and a slope 45 having the same angle as that of a spacer 43 is formed on a slide contact part between a torque cam groove 42, positioned opposite to the slope 44 of the spacer 43, and the spacer 43.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a V-belt type automatic transmission.

[0002]

2. Description of the Related Art For example, in a type of vehicle such as a scooter type vehicle which can be easily driven, an automatic transmission which is easy to operate is often used. In particular, the V-belt type automatic transmission has been used as a power transmission device for a long time, and a drive pulley and a driven pulley are connected by a single V-belt, and one face of each pulley is movable, and the V-belt is automatically driven. Is changed steplessly to change the speed ratio.

[0003] In recent years, V-belt type automatic transmissions are characterized by providing a torque detection mechanism.
When a high torque is required, such as when climbing a hill or accelerating, the pulley operates automatically and immediately changes to a low speed gear ratio.

FIG. 5A shows a high-speed running state in which the distance between the driven pulleys 1 is wide and the V-belt 2 is deep in the center. In this state, for example, if the vehicle suddenly goes uphill, a load is applied to the vehicle body, so that the rotation of the driven pulley 1 directly connected to the rear wheel is slowed down, but the inner (right side in the figure) pulley 1R (fixed driven face) The V-belt 2 tries to continue rotation, and there is a difference in rotation between the outer pulley 1L (movable driven face) and the inner pulley 1R.

[0005] Then, the oblique torque cam groove 6 formed in the outer boss 5 attached to the pin hole 4 formed in the inner boss 3 and rotating integrally with the outer pulley 1L (see FIG. 6). Cylindrical torque cam pin 7 protruding into the inside (rotating integrally with the inner pulley 1R)
Is pushed by the oblique angle of the torque cam groove 6 and is drawn toward the inner pulley 1R. As a result, as shown in FIG. 5B, the distance between the two pulleys 1R and 1L is reduced,
The V-belt 2 is driven radially outward of the driven pulley 1 to enter a low-speed running state with a large reduction ratio, that is, a high-torque state. These effects are generally called kickdown.

Since the torque cam pin 7 is constantly in sliding contact with the inside of the torque cam groove 6, the outer peripheral surface of the torque cam pin 7 and the inner peripheral surface of the torque cam groove 6 may be abraded, and smooth shifting operation may be hindered.

Therefore, in general, the torque cam groove 6 and the torque cam pin 7 are subjected to partial heat treatment such as induction hardening and tempering and laser quenching, or as shown in FIG.
In some cases, a cylindrical spacer 8 formed of a synthetic resin or the like is interposed between the torque cam groove 6 and the torque cam pin 7.

[0008]

However, when a partial heat treatment such as laser quenching is applied to the torque cam groove and the torque cam pin, the cost becomes extremely high. It is difficult to obtain accuracy, and this also leads to an increase in cost.

Even if a cylindrical spacer is interposed between the torque cam groove and the torque cam pin, a large load is applied to the torque cam pin in the direction of the sliding contact surface with the torque cam groove at the time of kick down, and the frictional force is reduced. And hinders smooth operation. In addition, the torque cam pins fall down due to this load, and pin holes and the like of the torque cam pins formed in the torque cam grooves and the inner bosses are worn, so that resistance is generated between the torque cam grooves and the torque cam pins, which hinders smooth operation.

The present invention has been made in view of the above circumstances, and has as its object to provide a V-belt type automatic transmission capable of reducing the load on the torque cam pins without increasing the cost.

It is another object of the present invention to provide a V-belt type automatic transmission in which the assemblability of a torque cam pin is improved.

[0012]

In order to solve the above-mentioned problems, a V-belt type automatic transmission according to the present invention has a V-belt between a drive pulley and a driven pulley. In the V-belt type automatic transmission, the torque cam pins are provided on a sleeve-shaped fixed face boss to which one of the driven pulleys is fixed, and the torque cam pins are provided on the outer peripheral surface of the fixed face boss. A torque cam groove in which the torque cam pin engages and slides is provided on a sleeve-shaped movable face boss to be fixed, and a spacer is interposed in a sliding contact portion between the torque cam pin and the torque cam groove, and the torque cam of the spacer is provided. An inclined surface is formed at a portion in sliding contact with the groove, and the torque cam groove facing the inclined surface of the spacer is in contact with the spacer. To contact portion is obtained by forming the inclined surface of the spacer and the same angle.

[0013] In order to solve the above-mentioned problem, an assembling hole having a diameter equal to or larger than the maximum diameter of the spacer is provided at one end of the torque cam groove. It is formed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan sectional view of a unit swing type engine 11 used in a small vehicle such as a scooter to which the present invention is applied. The unit swing type engine 11 is, for example, a four-cycle air-cooled single-cylinder engine body 1.
2 and a conductive case 13 extending rearward from one side of the engine body 12.

The engine body 12 mainly includes the engine case 1
4, a cylinder block 15 and a cylinder head 16, and a reciprocating motion of a piston 17 in the cylinder block 15 is transmitted through a connecting rod 18 to an engine case 14.
A crankshaft 19 extending in the vehicle width direction is rotated.

A transmission case 13 extending rearward from one side of the engine body 12, in this embodiment, from the left side, forms a belt chamber 20 therein, and a V-belt type automatic transmission 21 is disposed in the belt chamber 20. .

V is connected to one end of the crank rank shaft 19.
The drive pulley 22 of the belt type automatic transmission 21 is attached. On the other hand, the driven pulley 23 is a transmission mechanism 2 provided at the rear of the V-belt type automatic transmission 21.
4 is rotatably supported by a drive shaft 25 as an output shaft. In addition, these drive pulleys 2
A V-belt 26 is stretched between the driven pulley 2 and the driven pulley 23, and the rotational driving force of the engine is transmitted to the driven pulley 23 via the V-belt 26.

Further, the rotational driving force of the engine transmitted to the driven pulley 23 is transmitted to the drive shaft 25 via the centrifugal clutch mechanism 27. The drive shaft 25 is, for example, a drive gear 2 through a transmission mechanism 24 which is a reduction gear mechanism and also a power transmission device.
8, the rotational driving force is transmitted.

FIG. 2 is an enlarged cross-sectional view of a driven pulley 23 constituting a part of the V-belt type automatic transmission 21.
As shown in FIGS. 1 and 2, a plurality of bearings 29 are provided on the outer peripheral surface of the drive shaft 25 of the transmission mechanism 24.
A sleeve-shaped fixed face boss 30 is rotatably fitted in the circumferential direction via a via hole, and a dish-shaped fixed driven face 31 is fixed to an end of the fixed face boss 30. A sleeve-shaped movable face boss 32 is further fitted on the outer peripheral surface of the fixed face boss 30 so as to be slidable in the axial direction and rotatable in the circumferential direction. The movable driven face 32 is fixed. The movable driven face 32 and the fixed driven face 31 are arranged so as to face each other to form the driven pulley 23.

The outer peripheral surface of the movable face boss 32 is covered with a movable driven sheet 34. The end of the movable driven seat 34 on the movable driven face 32 side rises in the radial direction, and a drive plate 35 provided on the opposite side is provided.
(Described later) and the movable driven face 32 and the movable face boss 32 by the elastic force of a spring 36 provided therebetween.
To the fixed driven face 31 side.

On the other hand, a drum-shaped clutch housing 37 constituting the centrifugal clutch mechanism 27 is provided at an end of the drive shaft 25, and a clutch lining 38 as a friction engagement member is provided on the inner wall of the drum portion 37a of the clutch housing 37. Is provided. A clutch shoe 39 corresponding to the clutch lining 38 is provided on the drive plate 35, and the drive plate 35 is fixed to an end of the fixed face boss 30 and integrated.

FIGS. 3 (a), 3 (b) and 3 (c) are views at different positions as viewed from the direction of the arrow III in FIG. FIG. 4 is a sectional view taken along the line IV-IV in FIG. FIG.
As shown in (a), (b), (c) and FIG. 4, a pin hole 40 is formed on the circumferential surface of the fixed face boss 30,
The base of the torque cam pin 41 is fitted. The movable face boss 32 is formed with a torque cam groove 42 that is engaged with the torque cam pin 41 and that is obliquely movable and that is oblong in the axial direction and that is inclined in the circumferential direction. The opening of the torque cam groove 42 is covered with the movable driven sheet 34.

A spacer 43 made of a lubricating synthetic resin material such as, for example, ethylene tetrafluoride resin, polyacetal resin, or polyamide resin is interposed in a sliding contact portion between the torque cam pin 41 and the torque cam groove 42. The spacer 43 has a conical inclined surface 44 extending toward the center of rotation at a portion where the spacer 43 is in sliding contact with the torque cam groove 42, and is formed with the spacer 43 of the torque cam groove 42 facing the inclined surface 44 of the spacer 43. Spacer 43 also on sliding contact
And an inclined surface 45 having the same angle as the above.

As shown in FIG. 3C, an assembly hole 46 having a diameter equal to or larger than the maximum diameter of the spacer 43 is formed at one end of the elongated torque cam groove 42. The assembling hole 46 is formed outside the movable range of the torque cam pin 41 that moves in the torque cam groove 42 during normal use.

Next, the operation of the present embodiment will be described.

For example, in a high-speed running state in which the distance between the driven pulleys 23 is large and the V-belt 26 is deeply embedded in the center as shown in the upper half of FIG. It is close to one end of the torque cam groove 42 (top position).

In this state, if, for example, the vehicle suddenly goes uphill, a load is applied to the vehicle body, so that the rotation of the driven pulley 23 directly connected to the drive wheel 28 is slowed down. Attempting to continue, there is a difference in rotation between the movable driven face 32 and the fixed driven face 31.

Then, a torque cam pin 41 (which rotates integrally with the fixed driven face 31) projects into an oblique torque cam groove 42 formed in the movable face boss 32 that rotates integrally with the movable driven face 32. ) Is pushed by the oblique angle of the torque cam groove 42 and is drawn toward the fixed driven face 31 (low position, see FIG. 3B). As a result, as shown in the lower half of FIG. 2, the distance between the movable driven face 32 and the fixed driven face 31 is reduced, and the V-belt 26 is driven radially outward of the driven pulley 23 to drive the vehicle at a low speed with a large reduction ratio. That is, a high torque state is obtained.

At this time, a large load is applied to the torque cam pin 41 in the direction of the sliding contact surface with the torque cam groove 42. However, a spacer 43 is interposed in the sliding contact portion between the torque cam pin 41 and the torque cam groove 42. A conical inclined surface 44 that extends toward the center of rotation is formed in a sliding contact portion with the torque cam groove 42, and a spacer 43 is also formed in a sliding contact portion of the torque cam groove 42 with the spacer 43 facing the inclined surface of the spacer 43. The inclined surface 45 having the same angle as that of the torque cam groove 41
The load applied in the direction of the sliding contact surface with the rotation direction 2 also occurs in the direction of the rotation center, and the inclined surface 44 of the spacer 43 and the torque cam groove 4
Since the sliding contact area with the second inclined surface 45 is also increased, the load applied to the torque cam pin 41 is dispersed.

As a result, the torque cam groove 42 and the spacer 4
As a result, the torque cam pin 41 does not fall down due to the load, and wear of the torque cam groove 42 and the pin hole 40 of the torque cam pin 41 is prevented.

The spacer 4 of the torque cam groove 42
3 and the inclined surface 45 of the spacer 43
4, the opening of the torque cam groove 42 formed on the circumferential surface of the movable face boss 32 becomes narrower than the maximum diameter of the spacer 43, and it becomes difficult to assemble the spacer 43 and the torque cam pin 41. By forming the mounting hole 46 having the same diameter as or larger than the maximum diameter of the spacer 43 at one end of the torque cam groove 42 of the hole, the mounting of the torque cam pin 41 becomes easy.

Then, as described above, the torque cam pin 4
By disposing a spacer 43 having an inclined surface 44 on 1 to disperse the load, it is not necessary to perform a partial or total heat treatment such as laser quenching of the torque cam groove 42 and the torque cam pin 41, which was conventionally required. Therefore, an increase in cost can be prevented.

[0034]

As described above, according to the V-belt type automatic transmission according to the present invention, in the V-belt type automatic transmission having a V-belt stretched between a drive pulley and a driven pulley, A torque cam pin is provided on a sleeve-shaped fixed face boss to which one of the pulleys is fixed, and the torque cam pin is provided on an outer peripheral surface of the fixed face boss and the sleeve-shaped movable face boss to which the other of the driven pulleys is fixed is provided. A torque cam groove for engaging and sliding contact is provided, a spacer is interposed in a sliding contact portion between the torque cam pin and the torque cam groove, and an inclined surface is formed in a sliding contact portion of the spacer with the torque cam groove. An inclined surface having the same angle as that of the spacer is also formed in a portion of the torque cam groove which is opposed to the inclined surface of the spacer in sliding contact with the spacer. Since the load applied to the Torukukamupin is distributed, together with the frictional force between the torque cam groove and spacers is reduced, wear of such torque cam groove can also be prevented.

Further, since an assembling hole having a diameter equal to or larger than the maximum diameter of the spacer is formed at one end of the torque cam groove, the torque cam pin can be easily assembled.

[Brief description of the drawings]

FIG. 1 is a plan sectional view of a unit swing type engine showing an embodiment of a V-belt type automatic transmission according to the present invention.

FIG. 2 is an enlarged sectional view of a driven pulley.

FIGS. 3 (a), (b) and (c) are views taken along the arrow III in FIG. 2 at different positions.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

FIGS. 5A and 5B are enlarged cross-sectional views of a conventional driven pulley, in which FIG.
(B) shows a low-speed running state.

FIG. 6 is a view taken in the direction of arrow VI in FIG. 5;

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Unit swing type engine 21 V-belt type automatic transmission 22 Drive pulley 23 Driven pulley 26 V-belt 30 Fixed face boss 32 Movable face boss 41 Torque cam pin 42 Torque cam groove 43 Spacer 44 Slope sloper 45 Slope of torque cam groove 46 Assembly hole

Claims (2)

[Claims] 1. In a V-belt type automatic transmission in which a V-belt is stretched between a drive pulley and a driven pulley, a torque cam pin 41 is attached to a sleeve-shaped fixed face boss 30 to which one of the driven pulleys 23 is fixed. A torque cam groove 42 in which the torque cam pin 41 engages and slides is provided on a sleeve-like movable face boss 32 provided on the outer peripheral surface of the fixed face boss 30 and to which the other of the driven pulley 23 is fixed. A spacer 43 is interposed between the pin 41 and the torque cam groove 42 in sliding contact with the torque cam groove 42. An inclined surface 44 is formed in the sliding contact between the pin 41 and the torque cam groove 42, and the spacer 43 faces the inclined surface 44 of the spacer 43. The portion of the torque cam groove 42 that slides on the spacer 43 has the same angle as the spacer 43. A V-belt type automatic transmission, wherein an inclined surface 45 is formed. 2. The V-belt type automatic transmission according to claim 1, wherein an assembling hole having a diameter equal to or larger than a maximum diameter of the spacer is formed at one end of the torque cam groove.