JP2020026883A - Power transmission device of two-wheel barrow - Google Patents

Abstract

To provide a drive device that can more reduce an engine speed in engine braking than that in driving from a crank to prolong a distance that a two-wheel barrow can travel with inertia, thereby improving fuel economy of the two-wheel barrow.SOLUTION: A power transmission device of a two-wheel barrow comprises: a first power transmission path which is input at a reduced speed from a crankshaft and is arranged in parallel with the crankshaft to drive a rear wheel from a transmission using a plurality of gear pairs; a second power transmission path that drives the crankshaft from the rear wheel in engine braking; and a transmission path switching device that switches between the above two power transmission paths, wherein a crankshaft speed at the same vehicle speed is lower in engine braking than that in driving with an engine.SELECTED DRAWING: Figure 2

Description

Detailed description of the invention

  The present invention relates to a power transmission device for a two-wheeled vehicle that is driven at a reduced speed from a crankshaft and is arranged in parallel with the crankshaft to drive rear wheels from a transmission using a plurality of gear pairs.

Generally, a motorcycle is set to operate with a high engine speed relative to a traveling speed in order to enable light traveling. For this reason, the throttle opening is set so that the engine can quickly follow the throttle operation.However, since motorcycles are lightweight and have low running resistance, careful throttle operation is required for smooth running at a constant speed. Can be However, in actual running, when the running speed increases, even when the throttle is slightly released for speed adjustment, the engine is running at a high speed, so the engine brake that drives the crankshaft from the rear wheels acts strongly and suddenly A deceleration occurs, and the driving tends to be like opening the throttle again to match the target speed.
In this way, due to the characteristics of the motorcycle engine such as high rotation and high followability, the generation of strong engine brakes has reduced the proportion of vehicles that can use inertia to drive. It is desirable to suppress the engine braking action in order to enable fuel-efficient traveling by actively using inertia in driving.

  Therefore, the engine includes an engine brake occurrence state detecting means, an intake air amount adjusting valve for setting the engine braking force to a desired magnitude, a valve opening degree calculating means, and a valve control means for controlling the intake air amount adjusting valve. Patent Document 1 listed below adjusts the operation of the brake.

Japanese Patent No. 44344875

  In the invention described in Patent Literature 1, the engine intake air amount is controlled by detecting that the engine is in the engine brake from the maximum value of the intake pressure in one combustion cycle of the engine. In order to detect the intake pressure due to a minute change in throttle opening, a sensitive and precise sensor is required, and a precise valve control for air volume adjustment is also required. There was a problem that it was difficult. Further, in the invention described in Patent Document 1, the temperature of the catalyst provided in the exhaust passage for exhaust gas countermeasures to decrease the amount of intake air at the time of engine braking is reduced. When the operation is restarted after opening, there is also a problem that the activity of the catalyst is delayed and the exhaust gas purification efficiency is reduced.

  An object of the present invention is to reduce the engine braking force by using a simple structure and lowering the engine rotation speed than when driving from a crank by using a simple structure without using electronic control of the engine, thereby reducing the distance that can be coasted. An object of the present invention is to provide a drive device that can be made longer to improve the fuel efficiency of a motorcycle.

  In order to achieve the above object, a power transmission device for a two-wheeled vehicle according to the invention as claimed in claim 1 of the present application is a power transmission device that is decelerated from a crankshaft, is input from a transmission using a plurality of gear pairs, and is arranged in parallel with the crankshaft. A power transmission path for driving the wheels, and two power transmission paths for driving the crankshaft from the rear wheels during engine braking, and a transmission path switching device for switching between the two power transmission paths. The setting is such that the crankshaft speed at the same vehicle speed is lower during engine braking than when driven by the engine.

  As a result, the engine can be driven longer by utilizing the inertia by lowering the engine speed during engine braking than during engine driving.

  According to a second aspect of the present invention, an input shaft that is input from a clutch boss and moves on the main shaft is provided on the transmission main shaft, and two power transmission paths are switched between the input shaft and the main shaft. .

  Thus, the two power transmission paths can be switched between the clutch and the transmission with a simple configuration.

  In the invention according to claim 3, one power transmission path driven from the crank and two power transmission paths at the time of engine braking are switched by the axial movement of a selector on a torsion spline provided on the input shaft. It has a power switching device.

  Thus, the power transmission path can be switched by the difference in the rotational speed between the input shaft and the transmission main shaft.

  In the invention according to claim 4, the convex portion of the selector provided at the time of engine braking and the convex portion of the embed driven gear driven from the rear wheel are engaged as a dog clutch.

  Thus, power transmission from the rear wheels during engine braking is reliably performed.

  In the invention according to claim 4, the power transmission path during engine braking is transmitted from the gear of the drive shaft to the input shaft on the main shaft without passing through the transmission.

  As a result, the vehicle can always run at the lowest engine speed during engine braking, regardless of the selected gear position.

  According to a fifth aspect of the present invention, the power transmission path during engine braking is transmitted from the gear on the main shaft to the gear on the drive shaft through the transmission to the input shaft on the main shaft.

  As a result, an engine braking action corresponding to the gear position can be obtained, and the vehicle can run with the engine rotational speed set lower during engine braking than during engine driving.

  In the invention according to claim 6, the power switching device is provided in the clutch cover.

  This facilitates inspection and adjustment, and improves the maintainability of the power switching device.

  As described above, according to the present invention, the distance that can be run by inertia can be increased by reducing the engine speed at the time of engine braking compared to when driving from the crank with a simple structure, thereby improving the fuel efficiency of the motorcycle. Can be.

1 is a right side view of a motorcycle to which a power transmission device according to a first embodiment of the present invention is applied. It is a sectional view showing a power transmission course concerning a 1st embodiment of the present invention. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a front view which shows the shape at the time of the spring 39 at free time. FIG. 5 is a cross-sectional view of a main part illustrating the operation of the power switching device during engine braking. It is VI-VI sectional drawing in FIG. It is sectional drawing of the principal part explaining the structure of the power switching device in 2nd Embodiment.

  Hereinafter, a power transmission device according to a first embodiment of the present invention will be described with reference to the drawings.

  In FIG. 1, a motorcycle 1 includes an engine 4 in a lower portion of a front center of a front wheel 2 and a rear wheel 3, and a seat 5 in an upper portion. 7 is a leg shield for protecting the wind pressure of the rider's leg.

  As shown in FIG. 2, the engine 4 transmits the power of the crank 11 from the primary reduction gear to the multi-plate type shift clutch 13 through the centrifugal clutch 12, and uses a plurality of gear pairs arranged in parallel with the crank shaft. The rear wheels are driven by a chain 16 extending from a transmission 14 to a sprocket 15.

  The crank 11 is formed by press-fitting a left crank 17 and a right crank 18 into a crank pin 19. A piston (not shown) is attached to the upper portion of the crank pin 19 by a connecting rod 20, supported by bearings 21 and 22, and attached to left and right crankcases 23 and 24.

  The centrifugal clutch 12 transmits the rotation of the crank to the clutch drum 26 by a frictional force at a predetermined rotation speed by a centrifugal force of a clutch shoe 25 that rotates integrally with the right crank 18. The primary reduction drive gear 27 constituting the primary reduction gear is reduced by the clutch drum 26 to rotate the primary reduction driven gear 28, and power is transmitted to the clutch housing 29. A generator is attached to the left crank

  In the speed change clutch 13, a plurality of friction plates 30 and a clutch plate 31 are pressed from a pressure plate 33 by a clutch spring 32 from a clutch housing 29, and power is transmitted to a clutch boss 34 by a frictional force.

  Since the clutch boss 34 is integrally fixed to the input shaft 36 by the spline 35, the rotation of the primary reduction driven gear 28 is transmitted to the input shaft 36. The input shaft 36 constituting the power switching device has a torsion spline 37 integrally at the left end and a selector 38 attached thereto.

  A cross-sectional view passing through the selector 38 is shown in FIG. In the selector 38, a spring 39 is sandwiched in a groove portion, and a hairpin portion 39 a of the spring 39 is fitted in a slit of an outer peripheral bowl portion of the guide 40. As shown in FIG. 4, since the length of the spring 39 attached to the free-form selector 38 groove is shorter than the diameter of the selector 38 groove shown by the two-dot chain line, the spring 39 generates a frictional force by tightening. The frictional force due to this tightening is larger than the frictional force between the selector 38 and the torsion spline 37.

  The guide 40 is fastened and fixed to the right side of the transmission main shaft 41 by a spline and a spacer 42. The input shaft 36 is allowed to float on the spacer 42. Here, when the input shaft 36 rotates counterclockwise when viewed from the right, the selector 38 is pressed to the left end by the torsion spline 37 as shown in FIG. 2, whereby the input shaft 36 and the transmission main shaft 41 are integrated via the guide 40. The angle of the torsion spline 37 is set so as to rotate as follows.

  The transmission 14 using a plurality of gear pairs is formed integrally with the drive shaft 43 in the crankcases 23 and 24 of the transmission main shaft 41. The illustrated example shows a case of a constantly meshing four-speed transmission in which the gear pair arranged in the second row from the left is the top gear, and the sliding gear having a spline is selected by moving in the axial direction to operate the dog clutch. The gear is shifted by meshing. The main shaft 41 and the drive shaft 42 are supported by bearings and attached to the left and right crankcases 23 and 24.

  A serration is formed at the right end of the drive shaft 42, and an emblem drive gear 44 is fixed here and meshes with an emblem driven gear 45 on the input shaft 36. The embed driven gear 45 is attached to the input shaft 36 so as to move freely, and the number of teeth is set larger than that of the main shaft gear of the transmission top gear. The selector 38 is provided with a plurality of protrusions 38a, and the plurality of protrusions 45a provided on the embed driven gear 45 constitute a dog clutch.

  As described above, the input shaft 36, the selector 38, the spring 39, the guide 40, the emblem drive gear 44, the emblem driven gear 45 and the like provided on the right side (outside) of the right crankcase 24 are provided in the clutch cover 46 as a power switching device. ing.

  By operating a shift pedal (not shown), the push plate 47 pushes the push rod 48 to the right in conjunction with the shift pedal, and the push plate 49 pulls the pressure plate 33 away from the friction plate 30 against the load of the clutch spring 32. The clutch is disengaged and the shift operation can be performed smoothly.

  Next, the operation of the power transmission device for a motorcycle having the above configuration will be described.

  When the rotation speed of the crank 11 reaches a predetermined speed, the clutch drum 26 is rotated from the clutch shoe 25 of the centrifugal clutch 12 on the right crank 18, and the primary reduction driven gear 28 is reduced and rotated by the primary reduction drive gear 27, and the speed is changed. The clutch boss 34 is rotated by the frictional force between the friction plate 30 and the clutch plate 31 of the clutch 13 for use.

  Although the input shaft 36 is rotated by the clutch boss 34, the rotation of the clutch boss 34 rotates counterclockwise when viewed from the right, so that the selector 38 is pressed to the left end by the torsion spline 37 and rotates integrally with the guide 40. Therefore, the transmission main shaft 41 is rotated from the spline of the guide 40. The drive shaft 43 rotates from a selected gear pair in the crankcase of the transmission main shaft 41 via the dog clutch, and the rear wheel 3 is driven by the chain 16 from the sprocket 15. The above is the power transmission path when the rear wheel 3 is driven from the crankshaft 11.

  After accelerating to a predetermined speed, the throttle is loosened to run at the target speed. At this time, the motorcycle 1 runs by inertia, but the rotation of the crankshaft 11 immediately decreases. Therefore, the rotation is transmitted to the input shaft 36 from the guide 40 integrated with the transmission main shaft 41. For this reason, as shown in FIG. 5, the selector 38, which is given a frictional force by the spring 39 from the hairpin portion 39 a fitted on the outer peripheral bowl portion of the guide 40, moves rightward on the torsion spline 37, and the convex portion 38 a And the convex portion 45a of the embed driven gear 45 mesh with each other.

  Therefore, the embed driven gear 45 is rotated by the emblem drive gear 44 rotated from the drive shaft 43. At this time, the number of teeth of the embed driven gear 44 is set to be larger than that of the main shaft gear of the transmission top gear. The rotation speed of the embed driven gear 44 becomes lower than that of the main shaft 41. At this time, the selector 38 moves to the right side and is pressed by the frictional force of the spring 39 from the hairpin portion 39a fitted to the outer peripheral bowl portion of the guide 40, so that the convex portion 38a of the selector 38 and the embedded The engagement with the convex portion 45a as a dog clutch is performed. Then, the power from the rear wheel 3 during engine braking is reliably transmitted by the dog clutch. The spring 39 slides to absorb the difference in the number of rotations between the spring 39 and the groove of the selector 38. However, since the friction loss due to this is small, there is no problem. The above is the power transmission path during engine braking in which the crankshaft 11 is driven by the rear wheel 3.

As described above, since the drive path is switched by the selector between the time of driving from the engine and the time of driving from the rear wheel as the difference in the number of revolutions of the transmission main shaft and the input shaft, when the throttle is fully closed during traveling. Of course, even when the throttle is slightly loosened by adjusting the speed, the drive path is reliably switched. Regardless of the position of the gear position, the vehicle can always run at a lower engine speed when the engine is braked than when the engine is driven, so that a long distance using inertia can be run. As a result, the distance driven by the engine by opening the throttle is reduced, so that fuel-efficient driving is possible. Since the engine braking force is not weakened by opening the throttle and injecting excess air as in the conventional case, it is possible to reduce a decrease in the catalyst temperature at the same coasting distance during engine braking.
When the throttle is opened for acceleration, the engine speed instantaneously rises with good responsiveness. Therefore, even when the engine speed is low during engine braking, the vehicle can travel without feeling a delay in rotation.

  Further, an input shaft that is input from a clutch boss and moves on the main shaft is provided on the transmission main shaft, and a power transmission path is switched between the input shaft and the main shaft, so that the input shaft is provided with a torsion spline. Since the switching is performed by the axial movement of the selector, the switching of the power transmission path is performed instantaneously due to the difference in the rotation speed between the input shaft and the transmission main shaft, and the operation can be performed without delaying the acceleration and deceleration of the engine. With a simple configuration, the transmission can be implemented without any operation.

  Since the power switching device is installed inside the clutch cover, high reliability is achieved because it can be configured only with a machine without the need for precise sensors or electronic control, and high maintenance that enables maintenance and inspection if the clutch cover is removed. Can be

  Furthermore, in a vehicle equipped with a centrifugal clutch as in the embodiment, when the vehicle is inadvertently downshifted to a low gear such as a low gear during traveling, the operation may become unstable due to abrupt engine braking, but the Regardless of the gear, the engine brake rotation speed can always be lower than when driving with the top gear, so that the effect of being able to drive with peace of mind is obtained.

  Although the embodiment has been described with the centrifugal clutch, a hand clutch type in which the multi-plate clutch is manually operated may be used, and the number of shift speeds is not limited to four, and it is of course applicable.

  Next, a second embodiment of the power switching device will be described with reference to FIG. The same components as those in the first embodiment are given the same numbers.

  The input shaft 36 constituting the power switching device has a selector 38 having a torsional spline 37 at the left end and provided with a frictional force by a spring 39. The gear is integrally formed with the guide 50 which is fixed by the spline 37 on the right side of the transmission main shaft 41 and the spacer 42. The right side of the drive shaft 51 is a shaft, and an emblem drive gear 52 having two gears, one on the left and right, integrally with the gear meshing with the gear formed on the guide 50 and the other gear meshing with the emblem driven gear 45 is provided on the drive shaft 51. Idle. Note that the two gears need only be capable of transmitting rotation, and may be divided and connected by a dog clutch or the like instead of being integrated.

  Since the number of teeth of the emblem drive gear 52 that meshes with the guide 50 is larger than the number of teeth of the gear of the guide 50, and the number of teeth of the emblem drive gear 52 is larger than the number of teeth of the embed driven gear 45, The rotation speed is lower than the rotation speed, and the rotation speed of the embed driven gear 45 decreases.

  The operation of the power switching device of the second embodiment having the above configuration will be described.

  The rotation is transmitted from the clutch boss 34 to the input shaft 36, but the rotation of the clutch boss 34 rotates counterclockwise when viewed from the right, so that the selector 38 is pressed to the left end by the torsion spline 37, and rotates integrally with the guide 50. Then, the transmission main shaft 41 is rotated from the spline of the guide 50. The drive shaft 51 rotates from a selected gear pair in the crankcase of the transmission main shaft 41 via the dog clutch to drive the rear wheels. The above is the power transmission path when the rear wheels are driven from the crankshaft. This is the same operation as described in the first embodiment.

  Regarding the power transmission path during engine braking, when the vehicle is accelerated to a predetermined speed and then operated to loosen the throttle to run at the target speed, the motorcycle 1 runs by inertia at this time, but the crankshaft 11 rotates immediately. Lowers. Therefore, rotation is transmitted to the input shaft 36 from the guide 50 integrated with the transmission main shaft 41. Therefore, the selector 38 to which the friction force is applied by the spring 39 moves rightward on the torsional spline 37, and the convex portion 38 a of the selector 38 and the convex portion 45 a of the embed driven gear 45 mesh with each other. This is the same operation as that described in the first embodiment with reference to FIG.

  By the way, the embed driven gear 45 is rotated from the gear formed on the guide 50 through two gears of the emblem drive gear 52. At this time, the reduction ratio from the gear of the guide 50 to the embed driven gear 45 is reduced by the reduction of the transmission top gear. Since the ratio is set smaller than the ratio, the rotation speed of the embed driven gear 45 is lower than the rotation speed of the transmission main shaft 41.

  Therefore, the input shaft 36 is rotated at a lower rotation speed than the transmission main shaft 41 in accordance with the rotation speed of the transmission main shaft 41 which changes depending on the selection of the number of shift speeds of the transmission. Therefore, at the time of engine braking, a crankshaft rotation speed lower than when the rear wheel is driven from the crankshaft is obtained according to the number of shift speeds, regardless of the speed change speed.

  This is suitable for a case where it is easier to drive using an engine brake corresponding to the number of shift steps when traveling on a long slope or a steep slope. Even in this case, compared to the conventional case in which the crank is rotated by reversely driving from the rear wheels according to the number of gear stages, the crank rotation speed for each gear stage is lower, so that the running by inertia can be expanded, thereby improving fuel efficiency. Is obtained. Furthermore, since the engine braking effect of the conventional downshift can be obtained, sporty driving as a motorcycle can be enjoyed.

  The present invention is suitable for a small two-wheeled vehicle, but can also be applied to a saddle-ride type three-wheeled vehicle or an all-terrain four-wheeled vehicle (ATV).

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Front wheel 3 Rear wheel 4 Engine 5 Seat 6 Handle 7 Leg shield 11 Crank 12 Centrifugal clutch 13 Shift clutch 14 Transmission 17 Left crank 18 Right crank 25 Clutch shoe 26 Clutch drum 27 Primary reduction drive gear 28 Primary reduction Driven gear 29 Clutch housing 30 Friction plate 31 Clutch plate 34 Clutch boss 35 Spline 36 Input shaft 37 Torsion spline 38 Selector 38a Selector projection 39 Spring 40 Guide 41 Transmission main shaft 42 Spacer 43 Drive shaft 44 Emble drive gear 45 Emble driven gear 45a Emblem Driven gear projection 46 Clutch cover 50 Guide 51 Drive shaft 52 Emblem drive gear

Claims (7)

  A power transmission path which is decelerated from the crankshaft and is arranged in parallel with the crankshaft to drive the rear wheels from a transmission using a plurality of gear pairs; And a transmission path switching device for switching between the two power transmission paths, wherein the crankshaft speed at the same vehicle speed is set to be lower during engine braking than when driven by the engine. A power transmission device for a motorcycle.   2. The transmission according to claim 1, wherein an input shaft that is input from a clutch boss and moves on the main shaft is provided on the transmission main shaft, and two power transmission paths are switched between the input shaft and the main shaft. A power transmission device for a motorcycle according to any one of the preceding claims.   A power switching device for switching between one power transmission path for driving from the crank and two power transmission paths for engine braking by axial movement of a selector on a torsion spline provided on the input shaft. The power transmission device for a two-wheeled vehicle according to claim 1 or 2, wherein:   3. The power transmission device for a motorcycle according to claim 1, wherein a convex portion of the selector and a convex portion of an embed driven gear driven from a rear wheel are engaged as a dog clutch during engine braking.   The power transmission device for a motorcycle according to any one of claims 1 to 3, wherein a power transmission path during engine braking is transmitted from a gear of a drive shaft to an input shaft on a main shaft without passing through a transmission.   The power transmission path at the time of engine braking is transmitted from a gear on a main shaft to a gear on a drive shaft through a transmission and transmitted to an input shaft on the main shaft. Power transmission device for motorcycles.   The power transmission device for a motorcycle according to claim 1, wherein the power switching device is provided in the clutch cover.

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