Bicycle has finalized the design almost by 1879 since invention in 1818.In the last hundred years, its transmission principle does not change, because traditional chain-driving is fairly simple rationally, therefore continues to use this transmission for a long time.
Early eighties, the U.S. releases a kind of later-model bicycle transmission principle, i.e. rocker-type transmission principle (see figure 1), U.S. Patent number is (4,574,649) (see figure 2).This principle can be eliminated near the poor efficiency stroke of ordinary bicycle crank upper and lower dead center position, makes bicycle that higher exerting oneself be arranged, its effect can be laborsaving half.In addition, owing to adopted the rocker-type transmission, just can realize speed change as long as change the coupled position of chain on rocking bar, simple in structure, speed range is wider.But on gear shift mode, need stop doing business in the speed-change process of existing rocker-type vehicle scrunches, and this is totally unfavorable for carry out speed change in upward journey.Another significant drawbacks of rocking bar transmission is that bicycle can not be retrodicted, and when retrodicting, arbitrary rocking bar is put end position, just can not continue to retrodict, and may cause the inconvenience in the use.
The objective of the invention is to replace traditional transmission shifting mechanism with a kind of new transmission device and speed-changing mechanism.The present invention is on the basis of rocking bar transmission scheme, shortcoming at existing various speed-changing mechanisms, the design of " adaptive rate " has been proposed, make speed-change process have certain adaptive ability, promptly when going up a slope, can realize corresponding reduction of speed with the size of the gradient, and in the process of comformability speed change, needn't end to drive.But the present invention has designed the backward flywheel, and when bicycle was retrodicted, the very heavy automatic disengagement in the flywheel had realized retrodicting freely.
In addition, feel laborsaving two approach that have in the time of making the people by bike.The one, improve the driving efficiency of movable parts, the 2nd, come the total arrangement and the size of mechanism are optimized design with body mechanics's achievement in research, the bicyclist is felt comfortably cool when riding, easily, be easy to have an effect, produce the labour-saving and feel.The present invention has made the computation optimization result of mechanism's overall dimension through body mechanics's experimental investigation.
The present invention is on the basis of last application for a patent for invention numbers 87100698, has done comprehensive improvement.
Below in conjunction with accompanying drawing, introduce in detail particular content of the present invention.
Fig. 3 is the concrete structure of this car. On the axis of vehicle frame (1), left and right crank (2) is installed, the crank front end is pedal, rocking bar (3) fixedly links with crank at a certain angle. Rocking bar is originally as a speed change gear, in speed changing control mechanism and adaptive rate mechanism are arranged, the steel wire rope (4) of drawing by the lower end carries out gear change by the control crank (5) that is installed on the handlebar, and the position of slide block (7) on rocking bar of control chain (6) end is to realize speed change. Be installed in left and right two flywheels (8) and chain engagement on the rear axle, chain pull is passed on the rear wheel, drive bicycle and advance. Chain has left and right two sections, and the middle steel cable (9) that connects, steel wire rope are walked around the reverse wheel (10) that the axis front lower place is installed on the vehicle frame and realized commutation, and namely left and right sides pedal drives mutually this under that.
Figure (4) is the transmission mechanism stereogram, the relation that two cover mechanisms link by chain about can more clearly finding out. In the junction of steel wire rope and chain, an extension sleeve (11) with Telescopic is arranged, stage clip (12) and garden slide block (13) are arranged in this extension sleeve. When the chain pulling force strengthens, can automatically extend, change in order to the difference that adapts to speed change rear chain length, and alleviate the impulsive force that in the chain of pedal Upper-lower Limit position, produces. Below flywheel, about a chain cover (14) is respectively arranged, guarantee chain unlikely coming off when starting.
Figure (5) is the crank of rocker-type driving device, rocking bar and with respect to rear axle O
3Relative position.O
2Transmission center for bent axle.Marked the parameter symbol of respectively optimizing size on the figure.The mechanism size of rocker gear of the present invention through body mechanics test and ergonomics research, draws the reasonable target function, and machine Optimal design and calculation has as calculated drawn the optimization size of mechanism again, mainly comprises:
(1) crank length L
1=280~300 millimeters
(2) rocking bar and crank angle Φ=140 °~150 °
(3) crank center position O
2(axis that is equivalent to the transmission car) and the position O of rear shaft center
3Relative position coordinates be:
x
0=320~380 millimeters
y
0=50~80 millimeters
(4) ram travel position: maximum L
2=210~230 millimeters
Minimum L
2'=120~140 millimeters
Such size when riding, has comparatively ideal outputting power characteristic, and it is laborsaving that the bicyclist is felt relief.
Figure (6) be a rocking bar in-to-in transmission system, comprises variable speed control mechanism and suitable capable certainly control mechanism, and the right is passed on the bar handle that is installed on the handlebar by the steel rope (4) that links with pull bar (15).Slide block (7) is gone up by chain gusset piece (16) and is connected chain, links with flywheel again.Variable speed control mechanism wherein, by pull bar, raising speed tooth plate (17), reduction of speed tooth plate compositions such as (18).Tooth plate is used for controlling the motion of slide block, and the profile of tooth of tooth plate is a serration, and when tooth plate rose, slide block can skid off along the inclined-plane, can not slide to vertical surface, causes the unidirectional slidably trend of (being raising speed or reduction of speed).Groove is arranged on the tooth plate, and the sleeve minor axis (19) on the pull bar is in groove, and pull bar is spurred by steel rope by bar handle, and the sleeve minor axis horizontally slips in groove, makes two tooth plates alternately release or take in simultaneously, in realizing back, and raising speed, locking, four kinds of functions of reduction of speed.Stage clip (20) is installed between pull bar and the spring limiting board (21), guarantees that the backhaul action of pull bar realizes smoothly.Two pilot sleeves (22) are used for the motion of tooth plate is led, and guarantee the successfully upper and lower slip of tooth plate, realize the control to slide block.Adaptive control mechanism wherein, by slide bar (23), stage clip (24) and stop collar compositions such as (25).Slide block set is on slide bar, and two stage clips also are enclosed within on the slide bar, and the centre separates with stop collar, and the effect of stop collar is that slide block can be realized when two tooth plates all descend in automatic the returning.Pilot sleeve (26) is used for to stop collar guiding and spacing, and reed (27) and backing plate (28) are used for pushing down slide block, make the unlikely job-hopping of slide block.The propelling thrust that slide block slides along the chute on the rocking bar is from the pulling force of chain, and the direction of slip is subjected to the control of tooth plate, and slip institute zone of reach is the restriction of the pressure of stage clip again then, and the degree that this pressure confinement slide block glides (sliding) to the right realizes adaptation function.
Figure (7) but be backward flywheel (8), comprise sprocket wheel and backward control mechanism.Chain wheel set is contained on the rear axle shelves (29), is made up of chain wheel (30), left and right silk shelves (31), packing ring (32).Adjustment sheet (33) is used for regulating the gap of two row's balls, and side joint outer casing seat (34) in the chain wheel drives rear wheel by jack (35) and rotates.The backward control mechanism is made up of very heavy, shifting block (36), fuse (37), snap ring (38) and variable force spring (39).Shifting block is enclosed within on the very heavy axle, can push aside very heavy.The variable force spring housing is on the rear axle shelves, and when rear wheel just changes, and the friction drag between the rear axle shelves is very little.When wheel reversing, friction drag increases doubly a lot, so snap ring is obstructed, stirs shifting block, opens very heavyly, and sprocket wheel and rear wheel are thrown off, and carries out the bicycle unobstructive function of retrodicting.Very heavy spring (40) is used for recovering very heavy position in the process of normally riding.Backward is looked anticlockwise direction for A among the figure.
Bicycle with rocker in driving mechanism having function of self-adaptive speed variation of the present invention after manufacturing experimently into sample car, is done the examination of 20 kilometers comparative and is ridden, and when riding trippingly with mid ranger, common light roadster must catch up with strength just and can catch up with, and as seen this vehicle brisk labour-saving effect of riding is tangible.When going up a slope, as long as in advance handle is placed " reduction of speed " shelves, transmission system can be realized corresponding reduction of speed by gradient size automatically.Behind slope top, handle can be placed on and return middle-gradely automatically, then transmission system can be got back to mid ranger automatically, subsequently handle is put into the locking shelves, can fix on the middling speed position.
Ride interpretation of result according to examination, this kind vehicle the most comfortable labour-saving speed is mid ranger.And when going up a slope, the bicyclist wishes not interrupt to realize adaptive rate most with scrunching.Therefore, the key function of this device is two kinds of functions in self adaptation reduction of speed and automatic the returning.