JP3850639B2 - Vehicle power transmission device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power transmission device for a vehicle that transmits power from an engine to drive wheels via a continuously variable automatic transmission and a mechanical stepped automatic transmission, and more particularly, a simple one or two persons get on. The present invention relates to a power transmission device suitable for use in a small vehicle having a structure.
[0002]
[Prior art]
In recent years, from the viewpoint of reducing exhaust gas and energy consumption, a small vehicle that can be moved by one or two people has been developed and put into practical use.
Such a small vehicle is configured in a self-supporting form such as a four-wheeled vehicle or a three-wheeled vehicle. For example, as described in JP-A-9-286348, a small engine is used as a power source. It is used as a means that can be easily moved with low exhaust gas with low fuel consumption.
[0003]
In such a small vehicle, as described in JP-A-59-227523, JP-A-62-246648, JP-A-63-145854, JP-B-6-56196, etc. The power of the engine is transmitted to the drive wheels by a belt type continuously variable automatic transmission so that it can be operated easily.
Furthermore, in such a small vehicle, a mechanical automatic transmission is used together with a belt-type continuously variable automatic transmission, and engine power is generated by the belt-type continuously variable automatic transmission and the mechanical stepped automatic transmission. In addition to being transmitted to the drive wheels with a wide range of gear ratios, the transmission ratio of the belt-type continuously variable automatic transmission is suppressed, and the size of the pulley around which the belt is wound is suppressed.
[0004]
[Problems to be solved by the invention]
As mentioned above, there are some small vehicles that use both a belt-type continuously variable automatic transmission and a mechanical stepped automatic transmission. By using While there is an advantage that the structure is not complicated and it is small and the production cost is low, there is a problem that a shift shock due to a mechanical stepped automatic transmission occurs and the riding comfort of the vehicle is impaired.
[0005]
That is, the belt-type continuously variable automatic transmission changes the gear ratio by continuously changing the pulley width in accordance with the engine speed and continuously changing the diameter of the belt wound around the pulley. Therefore, although a shift shock is not generated, the mechanical stepped automatic shift generates a shift shock because the gear ratio is changed stepwise by switching a plurality of gears for shifting. Therefore, although the belt-type continuously variable automatic transmission can achieve smooth running without a shift shock, a shift shock due to a mechanical stepped automatic shift has occurred and the ride comfort of the vehicle has been impaired. .
[0006]
The present invention has been made in view of the above-described conventional circumstances, and achieves reduction of a gear ratio load on a continuously variable automatic transmission such as a belt type by using a mechanical stepped automatic transmission together with the mechanical stepped automatic transmission. It is an object of the present invention to provide a vehicle power transmission device that absorbs a shift shock caused by a step automatic shift by a continuously variable automatic transmission and realizes a comfortable ride without a shift shock as a whole.
In particular, an object of the present invention is to realize a comfortable driving comfort of a vehicle while realizing easy driving particularly required for a small vehicle without increasing the size of a continuously variable automatic transmission.
Further objects of the present invention will be apparent from the following description.
[0007]
[Means for Solving the Problems]
The present invention relates to a power transmission device for a vehicle that transmits engine power to a drive wheel via a continuously variable automatic transmission and a mechanical stepped automatic transmission. The shift operation timing of the stepped automatic transmission was set.
As a result, in the belt-type continuously variable automatic transmission, the mechanical stepped automatic transmission is in a state where there is still a margin for changing the pulley width between the low ratio and the top ratio (that is, the continuously variable automatic shift operation). Therefore, the gear change shock due to the gear change is absorbed and eliminated by the continuously variable automatic change operation (change in the interval between the pulley plates).
[0008]
Further, the present invention provides a mechanical stepped automatic transmission that is interposed between a high-speed gear and a low-speed gear provided on the same axis, and a high-speed gear that only passes over the low-speed gear. As a configuration provided with a one-way clutch bearing that allows a high-speed gear and a low-speed gear, the high-speed gear and the low-speed gear are arranged in a space that is as small as possible to reduce the size.
[0009]
According to the present invention, the continuously variable automatic transmission is a V-belt continuously variable automatic transmission provided on the upstream side of the mechanical stepped automatic transmission, and a belt is disposed on the movable plate of the driven pulley. In the direction of narrowing the plate interval of the driven pulley as the driving torque transmitted increases Movable plate Belt transmission by force in a direction to reduce engine rotation generated when the mechanical stepped automatic transmission is switched to the high speed gear side by providing a torque detection cam mechanism having a cam groove for generating a component force for moving Actively using the increase in power Movable plate Is moved, and the plate interval of the driven pulley is narrowed and shifted in the low ratio direction, thereby preventing a change in output due to a rapid decrease in the engine speed and preventing a shock.
[0010]
The present invention is not limited to a belt-type continuously variable automatic transmission, but other types of continuously variable automatic transmissions such as a frame-type continuously variable automatic transmission that changes a gear ratio steplessly by swinging a power transmission piece. Even if a machine is used, the same effect can be obtained.
The present invention can be applied to any type of vehicle. In addition to the two-wheel drive type in which the left and right drive wheels are driven and rotated using a differential mechanism, for example, the front two wheels and the rear one wheel The present invention can also be applied to a one-wheel drive type vehicle that drives and rotates one drive wheel without using a differential mechanism, such as a three-wheel vehicle.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described with reference to an embodiment shown in the drawings.
As shown in FIGS. 1 to 4, the small vehicle of this example is a four-wheeled vehicle having two wheels each on a front wheel 1 and a rear wheel 2, and one occupant (driver) is seated in the center. A single seat driving seat 3 is provided.
The basic vehicle structure of this small vehicle is a frame-type vehicle body frame 4 made of a metal pipe material such as aluminum and covered with a resin body cover 5, and further, above the body cover 5. A resin roof panel 6 is arranged to cover the upper part of the seating seat 3 of the occupant to constitute a cabin.
[0012]
Reference numeral 7 in the figure denotes a steering wheel. By applying a steering force from the steering wheel 7 via a steering mechanism (not shown), the front wheel 1 can change its direction so that the traveling direction of the vehicle can be arbitrarily changed. It has become.
Further, reference numeral 8 in FIG. 1 denotes a select lever provided on the side portion of the seat 3, and the mechanical two-speed automatic transmission can be selected to move forward or backward by the select lever 8 as will be described later. Yes.
[0013]
As shown in FIGS. 3 to 6, a frame-type swing frame 10 is attached to the rear portion of the vehicle body frame 4 so as to be swingable up and down with its tip as a pivot. A power unit 40 in which a continuously variable automatic transmission, a centrifugal transmission clutch type two-speed automatic transmission, a differential mechanism, and the like are integrated is provided. The rear wheels 2 are attached to the ends of a pair of drive shafts 80 protruding from the differential mechanism 45 of the power unit 40, and the left and right rear wheels 2 are driven by the power from the power unit 40. Yes.
[0014]
As shown in detail in FIGS. 5 and 6, the swing frame 10 has a structure in which a substantially T-shaped main frame 11 and a pair of trailing arms 12 are combined.
The main frame 11 welds a center pipe 14 extending in the vehicle length direction to the center of the main pipe 13 extending in the vehicle width direction, and further, a sub pipe 15 for supporting the power unit 40 between the main pipe 13 and the center pipe 14. It is a structure that is welded over.
[0015]
The main pipe 13 is attached to an axle block 18 that rotatably supports the drive shaft 80 via brackets 17 at both ends thereof, thereby supporting the rear wheel 2 attached to the drive shaft 80.
The center pipe 14 is inserted and supported with a slight margin in a support hole 4b formed in the rear end panel 4a of the vehicle body frame 4 at the front end thereof, thereby allowing the main pipe 13 to swing. The parallel slide movement is restricted. Note that a rubber ring bush 4c is provided in the support hole 4b to suppress wear and noise caused by a twist between the center pipe 14 and the support hole 4b.
[0016]
The trailing arm 12 is attached via a pivot pin 20 to a bracket 19 attached to the vehicle body frame 4 at the base end thereof, and can swing up and down around the pivot pin 20. Further, the trailing arm 12 is attached to the bracket 17 at the tip thereof via a mounting pin 21 and a rubber bushing 22, and swings and displaces around the pin 21 with the axle block 18 (main pipe 13). And the torsional displacement by the bending of the rubber bush 22 is permitted.
[0017]
Between each trailing arm 12 and the vehicle body frame 4, a suspension unit 25 in which a suspension spring and a shock absorber are assembled is provided. These suspension units 25 are connected to a bracket 26 attached to the vehicle body frame 4 and the trailing arm. 12 is pivotally attached to a bracket 27 attached to 12.
That is, the swing frame 10 swings up and down around the pivot pin 20 together with the rear wheel 2 as the vehicle travels, and the left and right sides of the swing frame 10 are deformed by the bending of the rubber bush 22 and the slight rotation around the axis of the center pipe 14. It operates independently and suspended so that a height difference can occur between the rear wheels 2.
[0018]
As shown in detail in FIG. 7, the power unit 40 is rubber-mounted at three points on the swing frame 10. That is, brackets 29 are attached to the center pipe 14 and the sub-pipe 15, rubber plugs 30 are attached to the brackets 29, front end portions (engine parts) of the power units 40 are attached to the rubber plugs 30, and brackets 31 are attached to the main pipe 13. The rubber plug 32 is attached to the bracket 31, the rear end portion (differential portion) of the power unit 40 is attached to the rubber plug 32, and the power unit 40 is elastically supported on the swing frame 10 at three points.
[0019]
Therefore, the power unit 40 swings together with the swing frame 10 to suspend the rear wheel 2, and the power unit 40 is rubber mounted on the swing frame 10, so that engine vibration is transmitted to the vehicle body via the swing frame 10. Further, since the swing frame 10 itself is also supported by the vehicle body via the rubber ring bush 4c and the rubber bush 22, transmission of engine vibration to the vehicle body is further prevented.
[0020]
As shown in detail in FIGS. 8 to 10, the power unit 40 includes an engine 41, an AC generator 42, a belt-type continuously variable automatic transmission 43, a mechanical two-speed automatic transmission 44 having a reverse gear, and a differential mechanism 45. The power output from the engine 41 is shifted by the belt-type continuously variable automatic transmission 43 and the mechanical two-speed automatic transmission 44, and this power is transferred from the differential mechanism 45 to the left and right rear wheels. 2 is transmitted to the drive shaft 80 connected to 2 respectively.
[0021]
The engine 41 is a small displacement internal combustion engine (in this example, 50cc The movement of the piston 47 due to combustion explosion is transmitted to the crankshaft 49 by the connection rod 48, and the engine power is output by the rotation of the crankshaft 49.
An AC generator 42 is connected to one end of the crankshaft 49, and electric power necessary for driving the vehicle is generated by the rotational power of the engine.
[0022]
A drive pulley 50 of a belt-type continuously variable automatic transmission 43 is attached to the other end of the crankshaft 49, and a first transfer shaft 51 that is supported in parallel with the crankshaft 49 is in a cylindrical first sub A transfer shaft 51a is rotatably provided coaxially, and a driven pulley 52 is attached to the first sub-transfer shaft 51a. The drive pulley 50 and the driven pulley 51 are hung by an annular belt 53 having a substantially V-shaped cross section. It is connected by turning.
The drive pulley 50 has a fixed plate 50a fixed to the crankshaft 49, and a movable plate 50b that is fitted to the crankshaft 49 with an axial groove and is rotated along with it, but is movable in the axial direction. Further, a holding plate 50c fixed to the crankshaft 49 is provided behind the movable plate 50b, and a centrifugal roller 50d is provided between the movable plate 50b and the holding plate 50c.
[0023]
On the other hand, the driven pulley 52 includes a fixed plate 52a fixed to the first sub-transfer shaft 51a, First sub-transfer shaft 51a And a movable plate 52b provided so as to be able to move in the axial direction while being fitted with a shaft groove. Further, the movable plate 52b is fixed to the fixed plate 52a side by a return spring 52c provided on the back surface thereof. Is being energized. In addition, First sub-transfer shaft 51a As shown in detail in FIG. 12, the shaft groove fitting portion between the movable plate 52b and the movable plate 52b is a torque detection cam mechanism for applying a belt lateral pressure to the movable plate 52b.
Therefore, when the engine speed (crankshaft speed) is small, the distance between the movable plate 52b and the fixed plate 52a is narrowed by the return spring 52c, and the belt-wrapping diameter of the driven pulley 52 is increased. The distance between the fixed plate 50a and the movable plate 50b is widened by the tension, and the belt winding diameter of the drive pulley 50 is reduced, and the belt transmission reduction ratio from the drive pulley 50 to the driven pulley 51 is increased.
[0024]
As the engine speed increases, the centrifugal roller 50d moves radially outward by centrifugal force and presses the movable plate 50b from behind, and the distance between the movable plate 50b and the fixed plate 50a is reduced, so that the drive pulley The belt wrapping diameter of 50 is increased, the tension of the belt 53 thereby increases the distance between the movable plate 52b and the fixed plate 52a against the return spring 52c, and the belt wrapping diameter of the driven pulley 52 is decreased. The belt transmission reduction ratio from the pulley 50 to the driven pulley 51 is reduced.
That is, according to the belt-type continuously variable automatic transmission 43, the speed reduction ratio gradually decreases as the engine speed increases, and the rotation speed of the first sub-transfer shaft 51a increases.
[0025]
A shoe plate 54 is fixed to the tip of the first sub-transfer shaft 51a, and a drum 55 is fixed to the tip of the first transfer shaft 51. A centrifugal shoe 56 is movable outwardly on the shoe plate 54. Thus, a centrifugal start clutch 57 is configured between the first transfer shaft 51 and the first sub-transfer shaft 51a.
That is, when the rotational speed of the first sub-transfer shaft 51a is small as in engine idling, the centrifugal shoe 56 is not pressed against the inner peripheral surface of the drum 55, and the rotational power of the first sub-transfer shaft 51a is As the engine speed increases, the centrifugal shoe 56 moves radially outward due to the centrifugal force and presses against the inner peripheral surface of the drum 55, so that the first transfer shaft 51 is moved to the first transfer shaft 51. The engine is connected to the first sub-transfer shaft 51 a and rotated, and engine power is input from the first transfer shaft 51 to the automatic transmission 44.
[0026]
Here, the case structure of the power unit 40 will be described. A space for housing the belt-type continuously variable automatic transmission 43 in a main case 58 attached to the engine block with bolts 58a, a mechanical stepped automatic transmission 44, and a differential mechanism 45. A space for accommodating the belt type continuously variable automatic transmission 43 is covered with a cover case 59 attached with a bolt 59a, and the mechanical stepped automatic transmission 44 and the differential mechanism 45 are The accommodated space is covered with a cover case 60 attached with a bolt 60a, and the power train mechanism from the engine 41 to the differential mechanism 45 is accommodated in an integral case.
[0027]
The belt type continuously variable automatic transmission 43 and the centrifugal start clutch 57 associated therewith are housed in a dry environment case space free of lubricating oil, while the mechanical stepped automatic transmission 44 and the differential mechanism 45 described in detail below are The oil is lubricated in the case space together with the lubricating oil. In this case structure, the space containing the belt type continuously variable automatic transmission 43, the mechanical stepped automatic transmission 44, and the differential mechanism 45 are accommodated. The space is isolated by a partition wall 58b of the main case 58, and the belt-type continuously variable automatic transmission 43 and the centrifugal start clutch 57 associated therewith are guaranteed to operate in a dry environment free of lubricating oil. The stepped automatic transmission 44 and the differential mechanism 45 are guaranteed to operate in a wet environment with lubricating oil.
[0028]
The first transfer shaft 51 passes through the partition wall portion 58b and is rotatably supported by the bearing 58c. Further, the first transfer shaft 51 is rotatably supported by the cover case 60 by the bearing 60b at the tip thereof. The bearing 58c is provided with a seal 58d for preventing the lubricating oil from entering the wet environment space into the dry environment space.
In the portion near the bearing 60b of the first transfer shaft 51, Gear part 51b A cylindrical second sub-transfer shaft 51c is coaxially fixed to a portion near the bearing 58c. Gear part 51b A cylindrical third sub-transfer shaft 51d is coaxially and rotatably provided between the first sub-transfer shaft 51c and the second sub-transfer shaft 51c. That is, when the first transfer shaft 51 rotates, the second sub-transfer shaft 51c always rotates together, but the third sub-transfer shaft 51d can rotate relative to each other without such rotation.
[0029]
A shoe plate 61 is fixed to the second sub-transfer shaft 51c, a drum 62 is fixed to the third sub-transfer shaft 51d, and a centrifugal shoe 63 is movably provided on the shoe plate 61. Thus, a centrifugal transmission clutch 64 is formed between the second sub-transfer shaft 51c and the third sub-transfer shaft 51d.
That is, in a state where the engine speed is relatively small and the first transfer shaft 51 is small, the centrifugal shoe 63 is not in pressure contact with the inner peripheral surface of the drum 62, and the rotational power of the first transfer shaft 51 is third. The second sub-transfer shaft 51c rotates to transmit engine power without being transmitted to the sub-transfer shaft 51d. On the other hand, when the engine rotation speed further increases and the rotation speed of the first transfer shaft 51 (that is, the second sub-transfer shaft 51c) increases, the centrifugal shoe 63 moves radially outward due to the centrifugal force, and the inside of the drum 62 is increased. The third sub-transfer shaft 51d is connected to the second sub-transfer shaft 51c and rotated while being in pressure contact with the circumferential surface, and engine power is transmitted by the third sub-transfer shaft 51d.
[0030]
A gear portion 51e is formed on the third sub-transfer shaft 51d, and a high-speed gear 65a for shifting is always engaged. Also, the first transfer shaft 51 Gear part 51b Is always meshed with the low-speed gear 65b, and the high-speed gear 65a is set to have a reduction ratio smaller than that of the low-speed gear 65b.
In the wet environment space of the case, a second transfer shaft 66 is provided in parallel with the first transfer shaft 51, and the second transfer shaft 66 is interposed between the main case 58 and the case cover 60 via bearings at both ends. It is supported rotatably. The high speed gear 65a is coaxially fixed to the second transfer shaft 66, and the low speed gear 65b is coaxially provided on the high speed gear 65a via a one-way clutch bearing 65c.
[0031]
The one-way clutch bearing 65c allows only the overtaking rotation of the low-speed gear 65b by the high-speed gear 65a. If the low-speed gear 65b rotates, the high-speed gear 65a rotates, but the high-speed gear 65b does not rotate. 65a can be rotated.
Therefore, in a state where the engine speed is relatively small and the centrifugal transmission clutch 64 is not connected, the engine power rotates the low speed gear 65b meshed with the gear portion 51b of the first transfer shaft 51 and is rotated by the one-way clutch bearing 65c. The second transfer shaft 66 is rotated via the high speed gear 65a.
[0032]
On the other hand, when the engine speed is further increased and the centrifugal transmission clutch 64 is connected, the engine power rotates the third sub-transfer shaft 51d and the high-speed gear 65a engaged with the gear portion 51e to rotate the second transfer shaft. 66 is rotated directly. In this case, the low-speed gear 65b also rotates in the same manner as described above, but the high-speed gear 65a overtakes the high-speed rotation by the one-way clutch bearing 65c.
That is, when the centrifugal transmission clutch 64 is not connected, the engine power is transmitted with the reduction ratio by the low speed gear 65b, and when the centrifugal transmission clutch 64 is connected, the engine power is transmitted with the reduction ratio by the high speed gear 65a. The automatic transmission can be realized by a simple and compact configuration in which the centrifugal transmission clutch 64 having a simple and compact configuration and two transmission gears 65a and 65b are arranged coaxially via a one-way clutch bearing 65c. ing.
[0033]
A gear shaft 67 having a gear formed on the outer periphery is provided on the second transfer shaft 66 so as to be rotatable and axially movable. A claw portion 67 a is provided at an end of the gear shaft 67. . The second transfer shaft 66 faces the claw portion 67a. Engagement piece 66a Is fixed, and the claw portion 67a is not moved during the normal forward movement shown by a solid line in FIG. Engagement piece 66a The gear shaft 67 rotates with the second transfer shaft 66.
The second transfer shaft 66 is provided with a reverse gear 68 between the gear shaft 67 and the low speed gear 65b, and the reverse gear 68 is rotatable on the second transfer shaft 66 via a bearing. . As shown in detail in FIG. 9, the reverse gear 68 is always connected to the gear portion 51b of the first transfer shaft via a reverse idler gear 68a rotatably supported by a case cover 60 via a bearing. When the first transfer shaft 51 rotates, it rotates in the opposite direction to the high speed gear 65a and the low speed gear 65b.
[0034]
The gear shaft 67 is formed with a circumferential groove 67c, and the shift fork 69 is engaged with the rotation of the gear shaft 67. Further, the gear shaft 67 and the reverse gear 68 have mutually opposing surfaces. Claw portions 67b and 68b are respectively provided. Further, a shift drum 70 is provided between the main case 58 and the case cover 60 so that both ends of the shift drum 70 are rotatably supported. The shift drum 70 protrudes outside the case via a lever (not shown). It is connected to the select lever 8 on the driver side.
[0035]
Therefore, when the driver operates the select lever 8 to the reverse position, the shift drum 70 is rotated, the gear shaft 67 is moved to the reverse gear 68 side by the shift fork 69, and the claw portions 67b and 68b are engaged with each other. Part 67a and Engagement piece 66a And the gear shaft 67 can be rotated in the opposite direction to the second transfer shaft 66 by the reverse gear 68. That is, the simple and compact reverse mechanism that uses the gear shaft 67 for both forward and reverse movements cuts off the rotational power in the forward direction from the second transfer shaft 66, and the reverse direction from the reverse gear 68. The gear shaft 67 can be rotated by the rotational power to.
[0036]
As described above, the gear shaft 67 is rotated forward by any one of the forward gears 65a and 65b selected by the centrifugal transmission clutch 64, and is rotated backward by the reverse gear 68 by the driver's select lever operation. 67, the ring gear 45a of the differential mechanism 45 is always meshed.
The differential mechanism 45 rotatably supports a case 45b to which a ring gear 45a is attached and fixed by a bearing 45c between a main case 58 and a case cover 60, and a pair of umbrella-shaped pinions 45d and a pair of pins 45d in the case 45b. The umbrella-shaped side gear 45e meshes with each other and is rotatably provided. A pair of output shafts 45f attached to the side gear 45e are connected to the left and right drive shafts 80, respectively. Therefore, rotation of the gear shaft 67 transmitted through the ring gear 45a in the forward or backward direction causes the case 45b to rotate, thereby causing both side gears 45e to rotate differentially via the pinion 45d, and to the drive shaft 80. The connected left and right rear wheels 2 are driven.
[0037]
The case cover 60 is provided with an oil pump 71 for pumping the lubricating oil to the bearing portion of the mechanical stepped automatic transmission 44 and the centrifugal shift clutch 64 that is oil-lubricated. It is connected to the two transfer shafts 66 and driven.
As shown in FIG. 10, on the swing frame 10, the power unit 40 has a differential mechanism 45 disposed at a position lower than the mechanical stepped automatic transmission 44 and a case together with the mechanical stepped automatic transmission 44 and the differential mechanism 45. The oil level H of the lubricating oil accommodated in the inner wet environment space is in a state where the lower part of the ring gear 45a is immersed.
[0038]
Accordingly, the lubricating oil is supplied to the gears of the differential mechanism 45 and the mechanical stepped automatic transmission 44 by the spring-up by the ring gear 45a, and the oil pump 71 pumps up the lubricating oil from the bottom of the wet environment space, Each of the bearings of the mechanical stepped automatic transmission 44 and the centrifugal transmission through the oil passage 60c formed in the cover 60, the oil passage 51f formed in the first transfer shaft, the oil passage 66b formed in the second transfer shaft, and the like. Lubricating oil is supplied to the clutch 64.
Note that the driven pulley 52 and the centrifugal start clutch 57 serving as a dry environment are disposed at a position higher than the mechanical stepped automatic transmission 44 with respect to the oil level H, and therefore combined with the shielding by the partition wall portion 58b. Intrusion of lubricating oil from the wet environment space to the dry environment space is reliably prevented.
[0039]
Further, in the upper part of the power unit 40, a plurality of recesses 72 a and 72 b are formed in the joint portion of the main case 58 and the cover case 60 in the substantially vertical plane, and the main case 58 and the cover case 60 are joined. As a result, a plurality of cavities are formed by the recesses 72a and 72b. Further, since the edges of the recesses 72a and 72b are alternately cut out, the plurality of vacant spaces are communicated with each other by a zigzag path 72c. Further, the lowermost portion of the plurality of vacant spaces communicates with a wet environment space in which the mechanical stepped automatic transmission 44 and the differential mechanism 45 are accommodated by a through hole 72d. Communicates with the outside.
That is, by such a structure, an oil breather passage having a labyrinth structure is formed in the upper portion of the power unit 40, and the oil component is separated from the oil mist gas generated in the wet environment space by the oil breather passage, thereby making the wet environment space. The remaining clean gas is released to the outside.
[0040]
According to the vehicle power transmission device having the above-described configuration, when the engine 41 is started and the idling operation state is established, the centrifugal start clutch 57 is disconnected and the engine power is not transmitted to the drive wheels 2.
When the engine speed increases, the centrifugal start clutch 57 is engaged, and the engine power transmitted through the belt 53 is decelerated by the low speed gear 65b and transmitted to the differential mechanism 45, whereby the rear wheel 2 is driven to rotate. Is done.
[0041]
Then, when the engine speed further increases and the rotation speed of the first transfer shaft 51 increases, the centrifugal transmission clutch 64 is engaged, and the engine power is transmitted to the differential mechanism 45 by the high speed gear 65a and the rear wheel 2 However, a shift shock caused by a reduction ratio gap between the low speed gear 65 b and the high speed gear 65 a is absorbed by a continuously variable automatic shift by the belt type continuously variable automatic transmission 43.
The high speed gear 65a is changed from the low speed gear 65b due to the operation of the centrifugal transmission clutch 64 to overlap with the continuous automatic transmission operation of the belt type continuously variable automatic transmission 43 performed by the displacement of the centrifugal roller 50d accompanying the change in the rotational speed of the engine 41. In the state where there is still room in the middle of the continuously variable automatic shifting operation from the low ratio to the top ratio, the switching from the low speed gear 65b to the high speed gear 65a is performed. The shift shock is absorbed by the margin of the shift operation.
[0042]
The absorption effect of the shift shock will be described in more detail as shown in FIG.
If power transmission is performed with the low speed gear 65b without switching gears, as shown in FIG. 11 (a), when the centrifugal start clutch 57 is connected, as indicated by B1 in FIG. When the rotational speed (Ne) of the engine 41 increases at the gear ratio of the low-speed gear 65b, the traveling speed (V) of the vehicle increases, and when the engine rotational speed (Ne) exceeds a predetermined value, As shown in part C in the figure, the continuously variable automatic shift operation is significantly performed to increase the vehicle running speed (V), and the continuously variable automatic shift operation from the low ratio to the top ratio is almost completed. When the traveling speed (V) exceeds a certain set value, the traveling speed (Ne) of the vehicle increases as the rotational speed (Ne) of the engine 41 increases again at the gear ratio of the low-speed gear 65b as shown by D1 in FIG. V) rises. In addition, A part in a figure is a sliding part at the time of start.
[0043]
On the other hand, similarly, when power transmission is performed with the high-speed gear 65a without performing gear switching, the gear is shifted on the traveling speed (V) axis as shown in FIG. 11B, and B2 in FIG. As the rotational speed (Ne) of the engine 41 increases with the gear ratio of the high-speed gear 65a as in the section, the traveling speed (V) of the vehicle increases, and this engine rotational speed (Ne) becomes a certain set value. When this is the case, the continuously variable automatic shifting operation is remarkably performed as indicated by C in the figure, the vehicle traveling speed (V) increases, and the continuously variable automatic shifting operation from the low ratio to the top ratio is performed. When the running speed (V) exceeds a certain set value when it is almost finished, the vehicle increases as the rotational speed (Ne) of the engine 41 rises again at the gear ratio of the high-speed gear 65a as shown by D2 in FIG. The traveling speed (V) increases.
[0044]
Here, in the power transmission device of the present example, the speed change operation by the mechanical stepped automatic transmission 44 is performed during the period in which the belt type continuously variable automatic transmission 43 is continuously variable (C section). Accordingly, as shown in FIG. 11 (c), when the centrifugal start clutch 57 is connected by combining the above two characteristics, the gear ratio of the low speed gear 65b as shown in the B1 portion in FIG. When the rotational speed (Ne) of the engine 41 increases, the vehicle traveling speed (V) increases, and when the engine rotational speed (Ne) exceeds a certain set value, the portion C in FIG. The stepless automatic speed change operation is performed as described above, and during this operation, the low speed gear 65b is switched to the high speed gear 65a. Thereafter, the gear ratio of the high speed gear 65a is changed as indicated by D2 in FIG. Increased engine speed (Ne) Running speed of the vehicle (V) is so as to increase with that.
Therefore, the shift shock by the mechanical stepped automatic transmission 44 is absorbed by the stepless change of the pulleys 50 and 52 of the belt type continuously variable automatic transmission 43, and a smooth running is realized as a whole.
[0045]
In more detail, First sub-transfer shaft 51a As shown in Japanese Utility Model Publication No. 62-33154, a torque detection cam mechanism as shown in FIG. 12 is formed in the shaft groove fitting portion between the movable plate 52b and the movable plate 52b. In combination with the operation, the shift shock of the mechanical stepped automatic transmission 44 is prevented.
That is, a cylindrical cam sleeve 81 provided on the first sub-transfer shaft 51 a is fixed to the movable plate 52 b of the driven pulley 52, and the first sub-transfer is inserted into the cam groove 82 formed in the cam sleeve 81. By inserting a roller pin 83 erected on the shaft 51a, a torque cam detection mechanism comprising a cam sleeve 81, a cam groove 82 and a roller pin 83 is used. First sub-transfer shaft 51a And the movable plate 52b are fitted in a shaft groove.
[0046]
Here, the cam groove 82 is First sub-transfer shaft 51a As a result, in the state where the transmission tension is applied to the belt 53 and the driven pulley 52 is rotating, the lateral pressure applied to the belt 53 acting on the movable plate 52b is caused by the spring 52c. The sum of the pressing force and the component force by the inclined cam groove 82 increases the pressure contact force of the movable plate 52b to the belt 53, thereby increasing the efficiency of belt-pulley transmission.
Conventionally, when switching from the low speed gear 65b to the high speed gear 65a is performed as described above, the rotational speed on the driven pulley 52 side (that is, the crankshaft 49 side) is reduced, thereby A shift shock is caused by a large change in the direction in which the engine speed decreases.
[0047]
However, in this example, when the switching from the low speed gear 65b to the high speed gear 65a is performed and a force is applied to reduce the rotational speed on the driven pulley 52 side, the transmission tension applied to the belt 53 is thereby increased. Then, a component force is generated by the inclined cam groove 82, and the movable plate 52b is moved in a direction approaching the fixed plate 52a to forcibly shift the belt type automatic transmission 43 to the low ratio side. The rotational speed can be kept as it is.
Therefore, even when the low speed gear 65b is switched to the high speed gear 65a, the engine speed is prevented from changing suddenly, and a shift shock is prevented.
[0048]
【The invention's effect】
As described above, according to the present invention, in the power transmission device for a vehicle that transmits engine power to the drive wheels via the continuously variable automatic transmission and the mechanical stepped automatic transmission, the speed change operation of the continuously variable automatic transmission. Since the speed change operation timing of the mechanical stepped automatic transmission is set to overlap with the above, the mechanical stepped automatic transmission achieves the reduction of the gear ratio burden on the continuously variable automatic transmission by the mechanical stepped automatic transmission. A shift shock due to a shift can be absorbed by the continuously variable automatic transmission, and a comfortable ride without shift shock as a whole can be realized.
[Brief description of the drawings]
FIG. 1 is a perspective view of a small vehicle according to an embodiment of the present invention viewed from the front side.
FIG. 2 is a perspective view seen from the back side of the small vehicle according to the embodiment of the present invention.
FIG. 3 is a perspective view in plan view of a small vehicle according to an embodiment of the present invention.
FIG. 4 is a side perspective view of the small vehicle according to the embodiment of the present invention.
FIG. 5 is a plan view showing a swing frame structure of a small vehicle according to an embodiment of the present invention.
FIG. 6 is a side view showing a swing frame structure of a small vehicle according to an embodiment of the present invention.
FIG. 7 is a side view showing a mount portion of a power unit of a small vehicle according to an embodiment of the present invention.
FIG. 8 is a cross-sectional plan view of a power unit of a small vehicle according to an embodiment of the present invention.
FIG. 9 is a plan view showing a part of a power unit of a small vehicle according to an embodiment of the present invention in different cross sections.
FIG. 10 is a partial cross-sectional side view of a power unit of a small vehicle according to an embodiment of the present invention.
FIG. 11 is a diagram for explaining a shift characteristic according to an embodiment of the present invention.
FIG. 12 is a sectional view showing a torque detection cam mechanism according to an embodiment of the present invention.
[Explanation of symbols]
2: rear wheel (drive wheel), 41: engine,
42: Belt type continuously variable automatic transmission, 44: Mechanical two-speed automatic transmission,
65a: high speed gear, 65b: low speed gear,
B1, D1: Low speed gear travel period, B2, D2: High speed gear travel period,
C: continuously variable transmission period, Ne: engine speed,
V: vehicle running speed,

Claims (3)

A vehicle power transmission device that transmits engine power to a drive wheel via a continuously variable automatic transmission and a mechanical stepped automatic transmission,
The continuously variable automatic transmission includes a drive pulley coupled to an engine crankshaft, a driven pulley coupled to an input shaft (first transfer shaft 51) of the mechanical stepped automatic transmission, a drive pulley and a driven pulley. A belt that is wound around and transmits power,
The mechanical stepped automatic transmission is a one-way clutch bearing which is provided between a high-speed gear and a low-speed gear provided on the same axis and allows only overtaking rotation of the low-speed gear by the high-speed gear. And a centrifugal transmission clutch 64 for switching between a high speed gear and a low speed gear,
Furthermore, a centrifugal start clutch that is connected by an increase in rotation of the driven pulley to connect the driven pulley to the input shaft of the mechanical stepped automatic transmission, and a mechanical start gear to switch from the low speed gear to the high speed gear. The centrifugal transmission clutch that is connected by the increase in the rotation of the input shaft of the automatic transmission is arranged on the support shaft of the driven pulley with the driven pulley being sandwiched,
Further, the vehicle power transmission device is characterized in that the shift operation timing of the mechanical stepped automatic transmission is set so as to overlap with the automatic shift operation region of the continuously variable automatic transmission. The power transmission device for a vehicle according to claim 1,
  The continuously variable automatic transmission includes a drive pulley provided on the upstream side of the mechanical stepped automatic transmission and connected to the crankshaft of the engine and a driven pulley connected to the input shaft of the mechanical stepped automatic transmission. It is a V-belt type continuously variable automatic transmission with a belt in between.
  The drive pulley is a pair of drive plates that are arranged with a fixed plate and a movable plate facing each other to hang the belt, and the movable plate is moved by increasing the rotation of the crankshaft to narrow the drive plate interval. A centrifugal roller that continuously changes the rotational force of the crankshaft and transmits it to the driven pulley,
  The driven pulley includes a pair of driven plates arranged so that a fixed plate and a movable plate are opposed to each other to hang the belt, and the driven pulley in the direction of narrowing the plate interval of the driven pulley as the driving rotational force transmitted by the belt increases. A vehicle power transmission device comprising: a torque detection cam mechanism having a cam groove for generating a component force for moving a movable plate. The power transmission device for a vehicle according to claim 1 or 2,
  A power transmission device for a vehicle, wherein the power transmission device is provided on the vehicle body via a trailing arm that swingably supports the drive wheels on the vehicle body.

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