Abstract:
A gear reduction unit for use particularly in an electric motorcycle. The gear reduction unit uses three adjacent gears. The three gears are straight cut gears, which make a sound when they turn together. The sound provides audio feedback so that bystanders can hear when the motorcycle is approaching, notwithstanding that the electric motor on the motorcycle is mostly silent.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0001]    The present general inventive concept is directed to a method, apparatus, and computer readable storage medium directed to a gear reduction box for use with an electric motorcycle. 
       Description of the Related Art 
       [0002]    Combustion engines make a recognizable sound when operated. Thus, the typical motorcycle driven by a combustion engine generates a recognizable “motorcycle” sound to the operator of the motorcycle as well as bystanders. 
         [0003]    Electric motorcycles (a motorcycle driven by an electric motor and battery instead of a combustion engine) are very quiet due to the quiet operation of electric motors. This can be disadvantageous for numerous reasons. Riders of electronic motorcycles may miss the “motorcycle” sound when riding. Electronic motorcycles may also be hazardous in that bystanders may not hear one approaching thus making them harder to avoid when crossing streets. 
       SUMMARY OF THE INVENTION 
       [0004]    It is an aspect of the present invention to provide an improved gear reduction unit. 
         [0005]    These together with other aspects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, will become apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which: 
           [0007]      FIG. 1  is a drawing of an entire electric motorcycle, according to an embodiment; 
           [0008]      FIG. 2  is a drawing of a gear box mounted to the electric motorcycle, according to an embodiment; 
           [0009]      FIG. 3  is a drawing showing how the gear box is mounted onto the electric motorcycle, according to an embodiment; 
           [0010]      FIG. 4  is a drawing showing the inside of the gear box, according to an embodiment; 
           [0011]      FIG. 5  is a drawing showing a shaft seal plate, according to an embodiment; 
           [0012]      FIG. 6  is a drawing showing how a sprocket is mounted, according to an embodiment; 
           [0013]      FIG. 7  is a drawing showing the rotation of gears inside the gear box, according to an embodiment; and 
           [0014]      FIG. 8  is a drawing showing a cross sectional view from the section plane indicated in  FIG. 2 , according to an embodiment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]    Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
         [0016]    The present inventive concept relates to a gear reduction unit (or “gear box”) for use with an electric motorcycle (a motorcycle powered by an electric, not combustion, engine). While electric motors themselves do not make very much noise, the gear box is designed to give audio feedback which changes pitch, volume, and tone at different speeds. 
         [0017]      FIG. 1  is a drawing of an entire electric motorcycle, according to an embodiment. 
         [0018]    An electric motorcycle  100  is shown which has a gear box  102 , a chain  101 , and a foot rest  103 . The gear box will receive power from an electronic motor and output that power to the chain  101 . The electric motorcycle has a motorcycle frame  109  and a rear wheel  110 . The electric motorcycle  100  can be a BRUTUS ELECTRIC MOTORCYCLE or any other kind. 
         [0019]    Aside from the fact that the electric motorcycle uses an electric motor, gear box, and chain configuration as described herein, the electric motorcycle otherwise operates and is structured as a standard combustion driven motorcycle. Note that an electric motorcycle does not need a transmission because electric motors generate all of their torque at low speeds. 
         [0020]      FIG. 2  is a drawing of a gear box mounted to the electric motorcycle, according to an embodiment. 
         [0021]    The gear box  102  comprises a cover plate  201  attached to a main body  202 . The main body  202  is attached to the motorcycle  100 . Fill bolt  210  (through a washer) is screwed into a gear oil level check hole  211 . When fill bolt  210  is removed, the oil level can be checked through the gear oil level check hole  211  (also referred to as “check hole”). When the fill bolt  210  is removed, if oil leaks out of the hole  211  then the gear box does not need more oil. If no oil leaks out of the hole  211 , then oil should be added to the hole  211  until it leaks out. 
         [0022]      FIG. 3  is a drawing showing how the gear box is mounted onto the electric motorcycle, according to an embodiment. 
         [0023]    An electric motor  302  is mounted to the motorcycle  100 . The electric motor  302  drives (turns) a motor shaft  303 . Note that the power (rotation) input to the motor shaft  303  will pass through the gear box (as described herein) and is output to a sprocket  304  which has a chain mounted on it. 
         [0024]    Bolts  300  pass through washers  301  which attach the main body  202  to the motorcycle  100  and the electric motor  302  (nuts on the opposite side which seal the bolts  300  are not shown). 
         [0025]      FIG. 4  is a drawing showing the inside of the gear box, according to an embodiment. 
         [0026]    The cover plate  201  is connected to the main body  202  via bolts  420  (while only two such bolts are illustrated there are many such bolts  420  which are used in the holes around the perimeter of the cover plate  201  and the main body  202 ). The cooperating nuts sealing the bolts  420  are not shown. 
         [0027]    The motor shaft  303  passes through a motor gear  400  and attaches inside a third outer bearing  412  (e.g., a ball bearing or other such bearing). All bearings described herein can be ball bearings or other suitable bearings. The motor shaft  303  has a key seat  407  which is a notch through the motor shaft  303  which is adapted to snugly receive a key  405 . The motor gear  400  has a keyway  406  which is also adapted to snugly receive the key  405 . Thus, when assembled, the key  405  fits inside the key seat  407  and the keyway  406  which serves to firmly connect the motor shaft  303  through the motor gear  400  (and hence the motor shaft  303  turns the motor gear  400 ). A keyway shaft clamp  408  (has two halves) fits inside a hole  421  which allows the motor shaft  303  to pass therethrough. 
         [0028]    A first end of an idle shaft  404  fits inside a second inner bearing  414 . The idle shaft  414  fits through (and turns) an idle gear  401 . A second end of the idle shaft  404  (opposite the first end) fits inside a second outer bearing  411 . 
         [0029]    A first end of an output shaft  403  fits inside a first inner bearing  413 . The output shaft  403  fits through (and turns) an output gear  402 . A second end of the output shaft  403  (opposite the first end) fits inside a first outer bearing  410 . 
         [0030]    All bearings herein (e.g., the first inner bearing  413 , the second inner bearing  414 , the first outer bearing  410 , the second outer bearing  411 , the third outer bearing  412 ) can be ball bearings or any other suitable type of bearing. 
         [0031]    Also shown in  FIG. 4  is a gasket  430  that fits between the cover plate  201  and the main body  202 . The gasket  430  can be made out of rubber and cushions the seal between the cover plate  201  and the main body  202  preventing a metal to metal seal. 
         [0032]      FIG. 5  is a drawing showing a shaft seal plate, according to an embodiment. 
         [0033]    A shaft seal plate  500  has a shaft seal  501  and an O-ring seal  502 . The seals (e.g., shaft seal  501 , O-ring seal  502 ) can be made of rubber and serve to seal the shaft seal plate so no fluid (such as oil) leaks therethrough. The seals fit in respective notches in the round cover plate. 
         [0034]      FIG. 6  is a drawing showing how a sprocket is mounted, according to an embodiment. 
         [0035]    The first end of the output shaft  403  fits through the shaft seal plate  500 . Note that in  FIG. 6  the opposite side of the shaft seal plate  500  is shown from the side shown in  FIG. 5 . The shaft seal plate  500  is attached directly to the main body  202  using four screws (or bolts). The sprocket  304  fits onto the first end of the output shaft  403  but cannot pass past where teeth on the first end of the output shaft  403  end. A bolt  600  (or screw) fits through one or more washers, through the sprocket, through the shaft seal plate  500 , and screws into the first end of the output shaft  403  thereby completing a sprocket assembly. In other words, the sprocket  304  fits tightly onto the first end of the output shaft  403 . Thus, when the output shaft  403  turns, it turns the sprocket  304 . 
         [0036]      FIG. 7  is a drawing showing the rotation of gears inside the gear box, according to an embodiment. 
         [0037]    The gear box operates as follows. The motor shaft  303  turns the motor gear  400 . The motor gear  400  turns the idle gear  401  (hence turning the idle shaft  404 ). The idle gear  401  turns the output gear  402  (hence turning the output shaft  403 ). Note that all of the gears in the gear box (the motor gear  400 , the idle gear  401 , the output gear  402 ) are all straight cut gears (as opposed to helical gears). The straight cut gears provide for an enhanced audio feedback (vs. using helical cut gears). 
         [0038]    The output shaft  403  turns the sprocket (not visible in  FIG. 7 ) which turns the chain  101  which propels the motorcycle  100 . Note that all three gears are adjacent to each other and in communication with each other, in other words one gear cannot turn without turning its neighbor(s). 
         [0039]    Note that in an embodiment, the motor gear  400  can have a diameter of 2 and 5/16 inches, the idle gear  401  has a diameter of 4.25 inches, and the output gear  402  has a diameter of 4.25 inches. The motor gear  400  can have 20 teeth, the idle gear  401  can have 41 teeth, and the output gear  402  can have 41 teeth. Note that the idle shaft  404  can be 6 spline which fits into the idle gear  401  which can also be a corresponding 6 spline and hence the configuration of both enables a tight fit. The output shaft  403  can be 6 spline which fits into the output gear  402  which can also be a corresponding 6 spline and hence the configuration of both enables a tight fit. The opposite side of the output shaft  403  that fits onto the sprocket  304  can be 13 spline (which fits onto a corresponding 13 spline sprocket  304 ). 
         [0040]    Note that there are two different sizes of bearings used. A small bearing is 2 and 1/16 inches in diameter and has a center hole ¾ inches in diameter. A large bearing is 2.5 inches in diameter and has a center hole 1⅛ inches in diameter. The small bearing is used on both sides of the idle shaft  404  (the second outer bearing  411  and the second inner bearing  414 ) and on the cover plate  201  side of the output shaft  403 . The large bearing is used on the main body  202  side of the output shaft  403  and the cover plate  201  side of the motor shaft  303 . The center holes on both bearing types (the small bearing and the large bearing) allow for a slip fit on their respective shafts. Note that “small” and “large” are relative terms and basically refer to the large bearing being larger in diameter than the small bearing, but otherwise any sizes can be used for the small bearing and large bearing no matter how large or small. 
         [0041]    Note that the particular parameters described herein (e.g., gear diameters, number of teeth, bearing sizes, spline numbers, etc.) merely represent one example of an embodiment of the inventive concept, and one of ordinary skill in the art would appreciate that numerous different parameters of the parts (e.g., different sizes, etc.) can be applied to the inventive concept which can still achieve the advantages of the inventive concept. 
         [0042]      FIG. 8  is a drawing showing a cross section of the gear box from the view indicated in  FIG. 2 , according to an embodiment. 
         [0043]    Note that the motor shaft  303  is parallel to the output shaft  403 . Referring back to  FIG. 2 , because of the configuration of the gear box (including the motor shaft  303  and the output shaft  403 ), the chain  101  passes behind the foot rest  103 . Therefore, there is little or no danger of the rider getting his/her foot caught in the chain since the chain is behind where the rider&#39;s legs and feet will be. 
         [0044]    The chain  101  also connects to a final drive gear on the rear wheel  110  of the motorcycle, thereby turning the rear wheel when the sprocket  304  is rotated. Of course the sprocket  304  is rotated whenever the motor shaft  303  is rotated, although at different speeds. 
         [0045]    Note that the connection between the sprocket  304  and the final drive gear on the rear wheel  110  takes advantage of being inboard and parallel to the motor for extra safety in the event of a chain break. Because the sprocket  304  is located where it is (inside the motorcycle frame  109  and away from the foot rest  103 ) the rider is much safer in the event of an incident or accident. The main body  202  itself acts as a chain guard when mounted to a motorcycle with rearset style footrest positioning. This eliminates the need for a special additional chain guard on a complete motorcycle which is required by DOT/NHTSA standards. 
         [0046]    The gear box can give a gear reduction ratio of 2.05:1 (or any other ratio). The sealed unit can also use gear oil for lubrication and cooling, and the main body can also act as a heat sink for the electric motor. Any type of chain can be used, such as #520, #525, #530. With the addition of a standard adapter, the output shaft can be hooked up to a driveshaft, thus enabling the gear box to be used in other applications as well (e.g., cars, boats, watercraft, etc.) 
         [0047]    The cover plate  201  and main body  202  can all be made of aluminum. All of the shafts and gears can be made of chromemoly steel. The bearings and seals are industry standard parts (e.g., bearings can be made out of metal or any other material standard bearings are made out of, and the seals can be made out of rubber or any other material standard seals are made out of). Although it can be appreciated, that any part described herein can be made out of any suitable material (e.g., steel, aluminum, any type of metal, plastic, rubber, etc., depending on the part.) 
         [0048]    Note that the absence of a part from the figures does not imply that such part does not exist. For example, all bolts can have a cooperating nut which may or may not be shown. All bolts and screws can also have a washer. Any such construction which is standard in the art can be applied to all constructs described and/or illustrated herein whether explicitly illustrated/described or not. If any aspect of the invention is not shown in the figures, then common sense can be applied to determine the structure of the non-illustrated portion utilizing the description herein and/or what is commonly known in the art. 
         [0049]    The many features and advantages of the invention are apparent from the detailed specification and, thus, it is intended by the appended claims to cover all such features and advantages of the invention that fall within the true spirit and scope of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.