WO2009096385A1

WO2009096385A1 - Power unit

Info

Publication number: WO2009096385A1
Application number: PCT/JP2009/051260
Authority: WO
Inventors: Kaoru Hanawa; Yutaka Imoto
Original assignee: Honda Motor Co., Ltd.
Priority date: 2008-01-31
Filing date: 2009-01-27
Publication date: 2009-08-06
Also published as: TW200949105A; JP2009180356A

Abstract

A power unit provided with a belt type stepless transmission. The power unit has a compression spring (43) for urging a movable pulley half (40) of a driven pulley (14) toward a stationary pulley half (30), and also has a centrifugal mechanism (20) for applying a thrust force, working against the urging force of the compression spring, to the movable pulley half. The compression spring (43) and the centrifugal mechanism (20) are arranged on opposite sides of the driven pulley to minimize the width of the power unit measured in the vehicle width direction.

Description

Power unit

The present invention relates to a power unit including a belt type continuously variable transmission.

A belt-type continuously variable transmission provided in a path for transmitting the rotational force of a crankshaft to drive wheels is known as disclosed in Patent Document 1. This belt-type continuously variable transmission is composed of a belt wound between a drive pulley unit and a driven pulley unit, and performs a speed change action by changing a winding diameter of the belt.

The belt-type continuously variable transmission disclosed in Patent Document 1 includes an input shaft side transmission pulley, an output shaft side transmission pulley, and a belt wound around these pulleys. The output shaft side transmission pulley includes an output side fixed pulley and an output side movable pulley.

At high speed, the movable pulley piece on the output side moves away from the fixed pulley piece on the output side so that the belt winding diameter decreases. The coil spring is compressed following the movement of the output side pulley piece, and the reaction force of the coil spring increases in proportion to the amount of compression. When the reaction force by the coil spring increases, the side pressure acting on the side edge of the belt increases. At this time, the transmission efficiency of the transmission may be reduced.

As a countermeasure, a centrifugal force imparting material is provided on the output side shifting pulley side. That is, the centrifugal force increases at a high speed, and the centrifugal force imparting material moves outward in the radial direction. By this movement, the extension part of the output side movable pulley piece moves away from the output side fixed pulley piece. By this movement of the extension portion, a force in a direction away from the output side fixed pulley piece is applied to the output side movable pulley piece. The force applied to the output side movable pulley piece plays a role of relaxing the pressing force to the belt by the coil spring. As a result, a reduction in transmission efficiency of the transmission can be suppressed.

The said coil spring is arrange | positioned in the position of the direction away from the output side fixed pulley piece of an output side movable pulley piece. Since the centrifugal force imparting material is disposed at a position further away from the output side fixed pulley piece than the position of the coil spring, the output shaft side speed change pulley is entirely separated from the output side fixed pulley piece. It protrudes greatly away. Thus, the large protrusion to one side may lead to an increase in the vehicle width in the case of a two-wheeled vehicle. In a two-wheeled vehicle with a limited vehicle width, it is necessary to suppress the protruding amount.
Japanese Patent Laid-Open No. H05-052245

An object of the present invention is to provide a power unit including a belt-type continuously variable transmission that does not protrude greatly to only one side of the vehicle width.

According to one aspect of the present invention, there is provided a power unit that performs belt-type continuously variable transmission, a driving pulley that transmits a rotational force from a crankshaft, and a driven shaft that transmits a rotational driving force from the crankshaft to driving wheels. The driven pulley is provided with a fixed pulley half body in which movement of the driven shaft in the axial direction is restricted, and movement of the driven shaft in the axial direction is possible. A movable pulley half, a belt wound between the drive pulley and the driven pulley, a biasing means for biasing the movable pulley half toward the fixed pulley half, and the driven pulley A centrifugal mechanism that applies a thrust force against the biasing force of the biasing means to the movable pulley half corresponding to the rotational speed of the biasing means, the biasing means and the centrifugal mechanism in the axial direction of the driven shaft The driven pulley Power unit that is arranged to be distributed as a quasi on both sides of the driven pulley is provided.

As described above, the centrifugal mechanism and the urging means are distributed and arranged on both sides of the driven pulley, so that only one side of the driven pulley unit is enlarged, that is, it is prevented from projecting to only one side of the vehicle width. be able to.

Preferably, the movable pulley half includes a movable umbrella portion that contacts one side surface of the belt, and a movable cylinder portion that extends from the movable umbrella portion in the direction of the urging means along the driven shaft. Thus, by connecting the centrifugal mechanism to the movable side cylinder portion, a thrust force against the urging force of the urging means is applied to the movable pulley half. Thus, since the centrifuge mechanism is connected to the movable side cylinder, the outer diameter of the centrifuge mechanism can be reduced, and the centrifuge mechanism can be easily made compact.

Preferably, the fixed pulley half is fixed to the other side surface of the belt, a fixed umbrella portion extending from the fixed umbrella portion in the direction of the urging means along the driven shaft, and inside the movable cylinder portion. And a fixed-side cylinder portion having a long-hole-like cam groove, and at least one pin protrudes from the movable-side cylinder portion toward the outer peripheral surface of the driven shaft and passes through the cam groove. By connecting the tip of the pin to the centrifugal mechanism, a thrust force against the urging force of the urging means is applied to the movable pulley half. Therefore, the existing torque cam mechanism composed of the pin and the cam groove can be used as it is. As a result, the number of parts for engaging the centrifugal mechanism with the movable cylinder portion can be reduced.

1 is a schematic diagram of a power unit according to a first embodiment of the present invention; FIG. 2 is an enlarged sectional view taken along line 2-2 in FIG. FIG. 2 is a cross-sectional view taken along line 3-3 in FIG. FIG. 3 is an exploded perspective view of the driven pulley shown in FIG. Sectional drawing which showed the action | operation of the driven pulley shown by FIG. It is the schematic of the power unit by 2nd Example of this invention.

(First embodiment)
The power unit 10 of the first embodiment shown in FIG. 1 is provided in a power transmission path for transmitting the rotational force of the crankshaft 12 driven by the piston 11 to the drive wheels W, and includes a drive pulley 13 and a driven pulley 15. The basic elements are the driven pulley unit 14 provided and the belt 16 wound between the driving pulley 13 and the driven pulley 15.

In this example, a final reduction mechanism 17 including a driving pulley 13, a driven pulley 15, a belt 16 and a plurality of gears is collectively stored in a power unit case 18, and an engine 19 is mounted on the front end of the power unit case 18. .

The driven pulley unit 14 includes a driven pulley 15, a centrifugal mechanism 20 provided on the driven shaft 21, and a centrifugal clutch mechanism 50. The driven pulley 15 includes a fixed pulley half 30 that does not move in the longitudinal direction of the driven shaft 21, and a movable pulley that is movable relative to the longitudinal direction of the driven shaft 21 so as to move away from or approach the fixed pulley half 30. It consists of half body 40.

As shown in FIG. 2, the centrifugal mechanism 20 includes a fixed inclined plate 22 fixed to the driven shaft 21, and is disposed to face the fixed inclined plate 22 via

steel balls

23, 23 and moves along the driven shaft 21. A movable tilting plate 24 that can be arranged, an inner cylinder 25 extending from the movable tilting plate 24 along the driven shaft 21, and the inner cylinder 25 supported on the driven shaft 21 so as to be rotatable and axially movable. It consists of a needle bearing 26. The needle bearing 26 is provided on the inner cylinder 25 so as to be slidable with respect to the driven shaft 21, or is provided on the driven shaft 21 slidable with respect to the inner cylinder 25.

The fixed pulley half 30 extends from the fixed umbrella 31 so as to cover the inner cylinder 25 and contacts the belt 16, and the tip is rotatable to the driven shaft 21 via the radial bearing 32. And a fixed-side cylinder portion 33 that is supported so as not to move in the longitudinal direction of the driven shaft 21. Reference numeral 34 is an oil seal interposed between the base portion of the fixed-side tube portion 33 and the inner tube 25.

The movable pulley half 40 extends so as to cover the movable side umbrella portion 41 that contacts the belt 16 and the fixed side cylindrical portion 33 from the movable side umbrella portion 41, is rotatable about the driven shaft 21, and is the longitudinal length of the driven shaft 21. The movable side cylinder part 42 supported by the fixed side cylinder part 33 so as to be movable in the direction, and the compression spring (biasing means) 43 that urges the movable side umbrella part 41 to the fixed side umbrella part 31. The biasing means may be a torsion spring in addition to the compression spring 43. 44 and 45 are oil seals.

From the inner peripheral surface of the movable side cylindrical portion 42, projecting

portions

46 and 46 are formed to project radially inward, and these projecting

portions

46 and 46 are in sliding contact with the outer peripheral surface of the fixed side cylindrical portion 33.

The centrifugal clutch mechanism 50 is provided at the distal end portion of the fixed side cylindrical portion 33 which is a position opposite to the position where the centrifugal mechanism 20 is provided with respect to the position of the belt 16. The centrifugal clutch mechanism 50 includes a cup member 51 provided on the driven shaft 21,

arm members

52, 52 extending from the fixed-side cylinder portion 33 toward the outer periphery of the cup member 51, and these arm members 52. , 52 is provided at

weights

53 and 53 which are swingably provided at the front end portion, and which swing when the applied centrifugal force increases and contact the cup member 51 to transmit power.

The cylinder 54 to which the compression spring 43 is attached is fitted on the outer periphery of the movable side cylinder portion 42. The cylindrical body 54 has a spring receiving portion 55 at one end near the movable side umbrella portion 41. The spring receiving portion 55 protrudes in a bowl shape toward the outside of the diameter of the cylindrical body 54. The compression spring 43 is attached to the outer periphery of the cylindrical body 54 along the longitudinal direction of the driven shaft 21.

That is, the compression spring 43 is mounted on the outer periphery of the cylindrical body 54 so as to be interposed between the

arm members

52, 52 of the centrifugal clutch mechanism 50 and the spring receiving portion 55, and the movable pulley half 40 is fixed to the fixed pulley half. Always energized to move in 30 directions. Thus, since the other end of the compression spring 43 is received by the

arm members

52, 52, a spring receiving portion for receiving the other end or a dedicated member is not required.

Since the movable side cylinder part 42 has projecting

parts

46 and 46 projecting inward in the diameter on the inner peripheral surface thereof, as shown in FIG. 3, it has a sufficient gap. The fixed side cylinder portion 33 is fitted. The fixed-side cylinder portion 33 is fitted into the inner cylinder 25 of the centrifugal mechanism 20. The fixed side cylinder portion 33 has a cam groove 58. The movable side cylinder part 42 has a pin 56 protruding from the movable side cylinder part 42 toward the driven shaft 21. The tip portion 57 of the pin 56 passes through the cam groove 58 and is connected to the inner cylinder 25. Therefore, the movable side cylinder portion 42 is mechanically connected to the inner cylinder 25 via the pin 56.

The cylindrical body 54 receives the compression spring 43 and prevents the pin 56 from coming out radially outward by centrifugal force.

As shown in FIG. 4, the cam groove 58 is provided obliquely so as to draw a spiral in the fixed-side cylinder portion 33.

By the way, if the movable pulley half 40 is rotated as indicated by the arrow (1), the pin 56 is guided by the cam groove 58, so that the movable pulley half 40 moves as indicated by the arrow (2). That is, when the rotational speed of the movable pulley half 40 exceeds the rotational speed of the fixed pulley half 30 and is relatively rotated, the pin 56 is guided by the cam groove 58, and the movable pulley half 40 moves to the fixed pulley half 30 side. Will do. Thereby, the force which pinches | interposes a belt with the fixed pulley half body 30 and the movable pulley half body 40 increases, for example, when trying to accelerate rapidly, it can prevent that a belt slips.

Such a mechanism is called a torque cam mechanism because it uses the cam groove skillfully. That is, the torque cam mechanism includes a cam groove 58 formed in the fixed-side cylinder portion 33 and a pin 56 extending from the movable-side cylinder portion 42.

The present invention is characterized in that the inner cylinder 25 is mechanically connected to the tip portion 57 of the pin 56 constituting the torque cam mechanism.

Although connected in the embodiment, the tip portion 57 of the pin 56 and the inner cylinder 25 may be in contact with each other.

Next, the operation of the driven pulley unit of the belt type continuously variable transmission configured as described above will be described with reference to FIG.

Referring to FIG. 5, when the driven pulley 15 rotates at high speed, the diameter of the belt 16 becomes small, and the movable pulley half 40 moves as indicated by the arrow (3). Then, the compression spring 43 contracts to generate a large spring reaction force. On the other hand, with the increase in rotation, the

steel balls

23, 23 move radially outward as indicated by arrows (4), (4). By this movement, the movable tilting plate 24 and the inner cylinder 25 move as indicated by the arrow (5). By this movement, the movable side cylinder portion 42 is pushed to the left in the drawing via the pin 56. Since the pressing force and the reaction force of the compression spring 43 are opposite to each other, a relaxed reaction force acts on the side surface of the belt 16, and a reduction in transmission efficiency of the belt type continuously variable transmission can be suppressed. .

In the first embodiment, as shown in FIG. 1, the compression spring 43 is disposed so as to be at a position opposite to the position of the centrifugal mechanism 20 provided near the drive wheel W with respect to the belt 16. Compared with the case where the compression spring 43 and the centrifugal mechanism 20 are collectively disposed on the right or left side of the driven pulley unit 14, the amount of protrusion from the driven pulley unit 14 can be reduced. That is, an increase in the size of only one side of the driven pulley unit 14 can be suppressed.

As shown in FIG. 2, the movable tilting plate 24 of the centrifugal mechanism 20 is connected to the movable side cylinder portion 42 via the inner cylinder 25 and the pin 56. Since the inner cylinder 25 has a small diameter, both the inner diameter and the outer diameter of the movable tilting plate 24 can be reduced. That is, if the centrifuge mechanism 20 is connected to the movable cylinder portion 42 via the pin 56, the inner diameter D1 of the centrifuge mechanism 20 can be reduced. If the inner diameter D1 is reduced, the outer diameter D2 of the centrifugal mechanism 20 can be reduced, and the centrifugal mechanism 20 can be easily made compact.

Further, as shown in FIG. 2, the centrifugal mechanism 20 is connected to the tip of the pin (tip portion 57) via the pin 56 and the cam groove 58. The existing torque cam mechanism can be used as it is for the pin 56 and the cam groove 58. As a result, the number of parts for connecting the centrifugal mechanism 20 to the movable cylinder portion 42 can be reduced.

The power unit 10 shown in FIG. 1 is suitable for a scooter type vehicle in which the power unit 10 swings up and down together with the drive wheels 13. However, the present invention can also be applied to a non-oscillating power unit. Such an example will be described as a second embodiment with reference to FIG. The same members as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

(Second embodiment)
FIG. 6 shows a non-oscillating power unit 10B.
A drive sprocket 62 is attached to the output shaft 61 of the final reduction mechanism 17, a driven sprocket 64 is attached to the axle 63 of the drive wheel W, and the drive chain 65 is wound between the two

sprockets

62, 64 as shown in FIG. This is different from the first embodiment. The drive chain 65, the driven sprocket 64, the axle 63, and the driving wheel W are swung in the front and back direction of the drawing. As a result, the power unit 10B can be fixedly attached to the vehicle body frame.

In the second embodiment, the non-oscillating power unit 10B can be disposed in front of the drive wheel W. The compression spring 43 and the centrifugal clutch mechanism 50 are arranged on the right side of the belt 16 in the drawing, and the centrifugal mechanism 20 and the final reduction mechanism 17 are arranged on the left side of the belt 16 in the drawing. As is apparent from the figure, the right overhang L1 and the left overhang L2 can be approximated with respect to the center axis 66 in the vehicle width direction passing through the center of the drive wheel W.

Although the first and second embodiments are applied to a two-wheeled vehicle, the first and second embodiments can be applied to a three-wheeled vehicle and a four-wheeled vehicle, and can be applied to a general vehicle.

The power unit of the present invention is suitable for a motorcycle.

Claims

A power unit that performs belt-type continuously variable transmission,
A drive pulley to which the rotational force from the crankshaft is transmitted;
A driven pulley provided on a driven shaft that transmits a rotational driving force from the crankshaft to a drive wheel, the driven pulley including a fixed pulley half that is restricted from moving in the axial direction of the driven shaft; A movable pulley half that is movable in the axial direction of the driven shaft,
A belt wound between the drive pulley and the driven pulley;
Biasing means for biasing the movable pulley half toward the fixed pulley half;
A centrifugal mechanism that applies a thrust force against the biasing force of the biasing means to the movable pulley half corresponding to the rotational speed of the driven pulley;
Consisting of
The power unit, wherein the urging means and the centrifugal mechanism are arranged so as to be distributed to both sides of the driven pulley with respect to the driven pulley in the axial direction of the driven shaft.
The power unit according to claim 1,
The movable pulley half comprises a movable umbrella portion that contacts one side surface of the belt and a movable cylinder portion that extends from the movable umbrella portion toward the biasing means along the driven shaft. By connecting the centrifugal mechanism to the movable side cylinder, a thrust against the urging force of the urging means is applied to the movable pulley half.
The power unit according to claim 2,
The stationary pulley half is fixed to the other side surface of the belt, and extends from the stationary umbrella portion toward the urging means along the driven shaft and is accommodated in the movable cylinder portion. A fixed-side cylinder portion having a long-hole-shaped cam groove, and at least one pin protrudes from the movable-side cylinder portion toward the outer peripheral surface of the driven shaft and passes through the cam groove, By connecting the tip of the pin to the centrifugal mechanism, a thrust against the urging force of the urging means is applied to the movable pulley half.