Abstract:
A vehicle speed limiting apparatus has added a limiting ring to a belt transmission in the vehicle to limit the travel of a passive disk in the belt transmission to achieve the purpose of speed limitation for the vehicle while permitting the maximal torque output during acceleration or climb.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     (a) Technical Field of the Invention  
         [0002]     The present invention is related to a vehicle speed limiting apparatus, and more particularly to one having a limiting ring added to a belt transmission to limit the speed without reducing the torque of the vehicle.  
         [0003]     (b) Description of the Prior Art  
         [0004]      FIG. 1  of the accompanying drawings shows a belt transmission  2  adapted to a vehicle generally available in the market, such as a motorcycle or a land vehicle. Wherein, the belt transmission  2  is disposed in a transmission case  11 , and the power from an engine  12 , which is transferred via a crankshaft  13  in a crankcase  15 , drives the belt transmission  2 . The belt transmission  2  includes a slide disk  21  disposed on the crankshaft  13 ; an active disk  22  disposed to the crankshaft  13  on the side of the slide disk  21 ; a taper plate  23  disposed to the crankshaft  13  on the other side of the slide disk  21 ; a counter weight ball  24  at where restricted between the slide disk  21  and the taper plate  23 ; a passive disk  26  disposed on a driven shaft  25  to transmit power to the driven shaft; a clutch  27  fixed to the driven shaft  25 ; and a bearing  29  disposed on a transmission case cover  111  of the transmission case  11  to support the driven shaft  25 . Wherein, the slide disk  21  and the active disk  22  constitute an active disk for the belt transmission  2 . One end of the belt  28  is located between the active disk  22  and the slide disk  21  while the other end of the belt  28  is located between the active disk  22  and the passive disk  26 .  
         [0005]     The engine  12  produces the power from explosions in the combustion chamber to push the piston  14  to conduct reciprocal movements, thus to drive the crankshaft  13  to rotate while both the slide disk  21  and the active disk  22  synchronously rotate. Meanwhile, the counterweight ball  24  moves for being subject to eccentric force. When throttled up, the rpm of the crankshaft  13  increases accordingly to throw the counterweight ball  24  out of its initial position to be subject to a greater eccentric force, and the slide disk  21  to be subject to the force by the counterweight ball  24  moves towards the active disk  22  to narrow the distance between the active disk  22  and the slide disk  21 , thus enabling the transmission belt  28  to expand the circumferential range of its rotation. Consequently, the rpm of the passive disk  26  is increased to further increase the speed of the vehicle via the acceleration of the driven shaft  25  driven by the clutch  27 .  
         [0006]     In contrast, in the case of throttle-down, the counterweight ball  24  is subject to a lesser eccentric force which increases the distance between the active disk  22  and the slide disk  21  in conjunction with the compression exercised by the transmission belt  28 , resulting in a reduced range of the circumferential rotation of the transmission belt  28 . Consequently, the rpm of the passive disk  26  is reduced to lower the rpm transmitted to the rear wheel(s), thus slowing down the vehicle.  
         [0007]     In certain countries, a speed limit is prescribed for vehicles. For the purposes of compliance, a speed limit apparatus is usually adapted to the vehicle. A speed limiting structure of the prior art as illustrated in  FIG. 2 , has a speed-limiting pipe  32  extending from an exhaust conduit  31  of an exhaust pipe  3  disposed below the engine  12 . The speed-limiting pipe  32  is generally a type of curved and closed metal pipe. Part of the exhaust resulting from the engine  12  is discharged from the outlet through the exhaust conduit  31  and another part of the exhaust will flow into and hit the bottom of the speed-limiting pipe  32 , then bounce back into the exhaust conduit  31  to create a disturbance at the open end of the speed-limiting pipe  32  as illustrated in  FIG. 3 . The high-pressure exhaust discharged from the outlet of the exhaust forms a resistance by the disturbance. Whereas a two-stroke engine running at higher rpm&#39;s takes advantage of the disturbance to harmonize the exhaust, in the case of a four-stroke engine, the speed limiting effect is prevented due to the counter pulsation being too small, and so the speed limiting method described above is applicable only to two-stroke engines and is not applicable to four-stroke engines. The exhaust from the engine  12  is at an extremely high temperature, making the speed-limiting pipe  32  prone to being deformed by the exhaust. The speed-limiting pipe  32  is also vulnerable to damage due to impact resulting from the speed limiting effect not being stable and the torque of the engine  12  dropping.  
       SUMMARY OF THE INVENTION  
       [0008]     The primary purpose of the present invention is to provide a vehicle speed limiting apparatus by adding a limiting ring to the belt transmission to limit the travel of the passive disk in the belt transmission to limit the vehicle speed without compromising the torque of the engine.  
         [0009]     The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.  
         [0010]     Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a schematic view showing a vehicle engine and a transmission of the prior art.  
         [0012]      FIG. 2  is a schematic view showing a speed-limiting structure of the prior art.  
         [0013]      FIG. 3  is a schematic view showing a local part of the airflow in the speed-limiting structure of the prior art.  
         [0014]      FIG. 4  is a schematic view showing a preferred embodiment of the present invention.  
         [0015]      FIG. 5  is a blow-up view of a local part of the preferred embodiment of the present invention.  
         [0016]      FIG. 6  is an exploded view of a limiting ring and a passive disk of the preferred embodiment of the present invention.  
         [0017]      FIG. 7  is a schematic view showing the combination of the limiting ring and the passive disk of the preferred embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.  
         [0019]     Referring to  FIG. 4  for a speed limiting structure of the present invention, a limiting ring A is disposed in a belt transmission T. The belt transmission T includes a slide disk  51  disposed on a crankshaft  4 ; an active disk  52  disposed on the crankshaft  4  on the side of the slide disk  41 ; a taper plate  53  disposed on the crankshaft  4  on the other side of the slide disk  51 ; a counter weight ball  54  accommodated and restricted between the slide disk  51  and the taper plate  53 ; two passive disks  72  and  73  disposed on a passive shaft  6 ; a clutch  71  fixed to the passive shaft  6 ; and a transmission belt  8 . Wherein, the slide disk  51  and the active disk  52  define an active disk  5  of the belt transmission T. One end of the transmission belt  8  is located between the active disk  52  and the slide disk  51  while the other end of the transmission belt  8  is located between those two passive disks  72  and  73 .  
         [0020]     A guide part  721  inserted onto the passive shaft  6  is provided to the passive disk  72 , and a guide cylinder  731  inserted onto the guide part  721  of the passive disk  72  is disposed to another passive disk  73 . A distance for movement is defined for the passive disk  73  between the guide cylinder  731  and the clutch  71  for the guide cylinder  731  of the passive disk  73  to move on the guide part  721  of the passive disk  72 . A spiral coil  9  is inserted between the outer side of the guide cylinder  731  of the passive disk  73  and the clutch  71 .  
         [0021]     Now referring to  FIGS. 5, 6  and  7 , the limiting ring A is inserted onto the guide part  721  of the passive disk  72  and is located on the external side of the guide cylinder  731  of the passive disk  73 . In case of throttle-up, the rpm of the crankshaft increases accordingly to throw the counter weight ball  54  out of its initial position for being subject to greater eccentric force, thus the slide disk  51  is made subject to the displacement of the counter weight ball  54  and moves toward the active disk  52  while the other passive disk  73  compresses the spiral coil  9  for the guide cylinder  731  of the passive disk  73  to slide towards the clutch  71 . Meanwhile, the moving distance of the guide cylinder  731  of the passive disk  73  is restricted by the limiting ring A, and therefore the range of the rotation circumference of the transmission belt  8  on both of the passive disks  72  and  73  is limited accordingly to conduct a proper limitation to the vehicle speed without affecting the maximal torque output for acceleration or climb.  
         [0022]     The speed limiting ring A disposed on the outer side of the end of the guide cylinder  731  of the passive disk  73  is used in the vehicle speed limiting structure of the present invention to achieve the purpose of limiting the vehicle speed.  
         [0023]     It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.  
         [0024]     While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.