Patent Publication Number: US-2023150355-A1

Title: Two-stage speed-change output device and electric vehicle using same

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to the technical field of speed change for electric vehicles. 
     DESCRIPTION OF THE PRIOR ART 
     Small electric vehicles are primarily power-assisted bicycles or electric bicycles, of which a driving source involves a motor assembly that is operable to drive wheels. Generally, the motor assembly is mounted on a vehicle frame and is connectable, by means of an output wheel (which can be a toothed wheel or a frictional wheel), with a transmission assembly arranged on a crankshaft (of a power-assisted bicycle) or a vehicle wheel hub (of an electric vehicle), so as to fulfill the purpose of assisted driving. Since the motor assembly and the transmission assembly are arranged separately, the number of the assemblies is large, occupying a large space, and inevitably increasing costs and difficulty of fabrication, and also adding vehicle loading and causing additional consumption of energy. 
     Further, to conduct speed change in order to handle different traveling situations, such as high speed low torque (on a flat road) or low speed high torque (on an upslope or carrying high load), the electric vehicle may be necessarily and additionally equipped with a speed change mechanism coupled to an output spindle of the motor assembly, and a speed change control unit is involved to conduct switching between various speeds. This further increase the number of components and the space occupied thereby, and also adds control wiring. And, in addition to the above problems, this also increase the probability of damage and requirement for servicing. This invention is made to address the above problems of an excessively large number of components and a large spaced occupied thereby. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide a two-stage speed-change output device, which realizes speed change of two stages by making use of forward and reverse rotations of a motor, exhibiting an effectiveness of easy operation. 
     Further, a second objective of the present invention is to provide an electric vehicle that uses a two-stage speed-change output device, in which the two-stage speed-change output device occupies a relatively small amount of space and is applicable to driving and speed changing for a small-sized electric vehicle, realizing great enhancement of the utilization thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of the present invention. 
         FIG.  2    is a cross-sectional view showing relationships among various components thereof. 
         FIG.  3    is an exploded view showing components and configurations of a first speed-change assembly of the present invention. 
         FIG.  4    is an exploded view, taken from a different angle, showing the components and configurations of the first speed-change assembly of the present invention. 
         FIG.  5    is an exploded view showing components and configurations of a second speed-change assembly of the present invention. 
         FIG.  6    is an exploded view, taken from a different angle, showing the components and configurations of the second speed-change assembly of the present invention. 
         FIG.  7    is a cross-sectional view of present invention, taken from line A-A of  FIG.  2   . 
         FIG.  8    is a cross-sectional view of present invention, taken from line B-B of  FIG.  2   . 
         FIG.  9    is a cross-sectional view of present invention, taken from line C-C of  FIG.  2   . 
         FIG.  10    is a cross-sectional view of present invention, taken from line D-D of  FIG.  2   . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A two-stage speed-change output device according to the present invention is constructed as shown in  FIGS.  1  and  2   , and comprises a main axle  100 , a motor assembly  10 , a first speed-change assembly  20 , a second speed-change assembly  30 , and an output shell  40 . The motor assembly  10  is operable to drive and rotate the first speed-change assembly  20  in a reverse or backward direction and to drive and rotate the second speed-change assembly  30  in a forward direction to allow the first and second speed-change assemblies  20 ,  30  to individually drive the output shell  40  in the same direction, so that the two-stage speed-change output device may carry out switching for two-stage speed change by using the forward and backward rotations of the motor assembly  10 . 
     With regards to a detailed structure of the two-stage speed-change output device, reference is made to  FIGS.  2  and  5   . The motor assembly  10  includes a main axle  100  on which an input sleeve  11  is rotatably mounted by means of a plurality of bearings. An electromagnetic mechanism  12  is mounted to an end of the input sleeve  11 , so that the electromagnetic mechanism  12 , when electrified and energized, and thus excited, drives the input sleeve  11  to rotate forward and backward relative to the main axle  100 . Further, the motor assembly  10  comprises an external motor housing  13  mounted on the main axle  100  at an outer side of the electromagnetic mechanism  12 , and the motor assembly  10  comprises an internal motor housing  14  arranged at an inner side of the electromagnetic mechanism  12  to be combined with the external motor housing  13 , wherein an axle seat  15 , which is rotatably mounted on the input sleeve  11 , is fit in and mounted to a center of the internal motor housing  14 , so that the input sleeve  11  extends through and projects out of the internal motor housing  14  to drive the first and second speed-change assemblies  20 ,  30 . 
     As shown in  FIGS.  2 ,  3 , and  4   , the first speed-change assembly  20  is arranged between the main axle  100  and a corresponding end of the input sleeve  11  that extends out of the motor assembly  10 . The first speed-change assembly  20  comprises a first carrier frame  21  that is fixed to the end of the input sleeve  11  by a sleeve fastener  16 . The first carrier frame  21  has two opposite surfaces on which a first planet group  22  and a second planet group  23  are respectively arranged. The first and second planet groups  22 ,  23  each comprise a plurality of first planets  220  and second planets  230  of the same contour. The first and second planets  220 ,  230  are respectively fastened to each other, so that the first and second planets  220 ,  230  are individually rotatable (spinning), in the same direction and in a synchronized manner, on the first carrier frame  21 . Further, a first sun gear  24  is fixed on the main axle  100  and in mating engagement with each of the first planets  220  of the first planet group  22  (as shown in  FIG.  7   ). A first shell  25  is rotatably mounted on an outer circumference of the first carrier frame  21  by means of bead groups on two sides thereof. One side of the first shell  25  that is opposite to the second speed-change assembly  30  is provided with a shell cover  250  fastened thereto for constraining or positioning the bead groups, and on a surface of an opposite side of the first shell  25 , a transmission wheel disc  26  that is rotatably mounted on the input sleeve  11  is fixed. The transmission wheel disc  26  is provided, on a center thereof, with a second sun gear  27  and a third sun gear  28  that are respectively arranged on two opposite sides thereof, wherein the second sun gear  27  of the transmission wheel disc  26  is in mating engagement with each of the second planets  230  of the second planet group  23  (as shown in  FIG.  8   ). The third sun gear  28  of the transmission wheel disc  26  is connected with the second speed-change assembly  30 , so that an input power that is input through the input sleeve  11  is transmitted through the first speed-change assembly  20  to the second speed-change assembly  30 . A first one-way clutching element  29  is fit on an outer circumference of the first shell  25  (as shown in  FIG.  7   ). The first one-way clutching element  29  is operable in either the forward direction or the backward direction, and in the present invention, a primary example for implementing the first one-way clutching element  29  is operating in the forward direction and idling in the backward direction. The output shell  40  is fit on an outer circumference of the first one-way clutching element  29 , so that the input power is transmitted through the input sleeve  11 , the first and second planet groups  22 ,  23  of the first carrier frame  21 , the transmission wheel disc  26 , the first shell  25 , and the first one-way clutching element  29  to be outputted through the output shell  40 . 
     As shown in  FIGS.  2 ,  5 , and  6   , the second speed-change assembly  30  is arranged between the first speed-change assembly  20  and the motor assembly  10 . The second speed-change assembly  30  comprises a second carrier frame  31  that is mounted on the axle seat  15  of the motor assembly  10 . A third planet group  32  is arranged on a surface of the second carrier frame  31  that corresponds to the first speed-change assembly  20 , and the third planet group  32  comprises a plurality of third planets  320  that are of the same contour. Each of the third planets  320  of the third planet group  32  is in mating engagement with the third sun gear  28  of the transmission wheel disc  26  of the first speed-change assembly  20 , so that the transmission wheel disc  26  drives each of the third planets  320  of the third planet group  32  to rotate. Further, a second shell  33  is rotatably mounted on an outer circumference of the second carrier frame  31  by means of bead groups on two sides thereof. One side of the second carrier frame  31  that is opposite to the first speed-change assembly  20  is provided with a shell cover  330  fastened thereto for constraining or positioning the bead groups, and the second shell  33  is provided, on an inner circumference thereof, with an internal ring toothed section  331  that is in mating engagement with an outer circumferential of each of the third planets  320  (as shown in  FIG.  10   ), so that the third planet group  32  drives, by means of each of the third planets  320 , the second shell  33 . Further, a second one-way clutching element  34  is fit to an outer circumference of the second shell  33 , and the second one-way clutching element  34  is a one-way clutching element that is operable in the same direction as the above-mentioned first one-way clutching element  29 . An outer circumference of the second one-way clutching element  34  is joined with the output shell  40 , so that the input power is transmitted through the input sleeve  11 , the first and second planet groups  22 ,  23  of the first carrier frame  21 , the transmission wheel disc  26 , the third planet group  32  of the second carrier frame  31 , the second shell  33 , and the second one-way clutching element  34  to output through the output shell  40 . According to some embodiments, a third one-way clutching element  35  is arranged between the second carrier frame  31  of the second speed-change assembly  30  and the internal motor housing  14  of the motor assembly  10 , and the third one-way clutching element  35  is a one-way clutching element that is operable in the same direction as the above-mentioned first and second one-way clutching elements  29 ,  34 . In case that an input power is inputted, in a reversed direction, from the output shell  40 , the second speed-change assembly  30  is in idling rotation with respect to the motor assembly  10  so as not to affect internal components thereof. 
     According to some embodiments, as shown in  FIGS.  2 - 6   , the two-stage speed-change output device according to the present invention is applicable to a wheel hub assembly  50  of an electric vehicle. The wheel hub assembly  50  comprises a first wheel hub shell  51 , a second wheel hub shell  52 , and an internal wheel hub shell  55 . Fasteners are applied to fix, in sequence, outer flanges or rims of the first wheel hub shell  51 , the output shell  40 , the internal wheel hub shell  55 , and the second wheel hub shell  52 , wherein the first wheel hub shell  51  is rotatably mounted, at a center thereof, on the main axle  100 , and the internal wheel hub shell  55  is rotatably mounted, on an inner circumference thereof, on an outer circumference of the internal motor housing  14  of the motor assembly  10  by means of bead groups on two sides thereof. One side of the internal wheel hub shell  55  that is opposite to the second speed-change assembly  30  is provided with a wheel hub cover  56  fastened thereto for constraining or positioning the bead groups. Further, outer flanges of the first wheel hub shell  51  and the second wheel hub shell  52  are provided for connecting a plurality of spokes (not shown) of the vehicle wheel rim, so that the two-stage speed-change output device according to the present invention may be applied to drive a wheel of the electric vehicle and also to conduct switching or changing of speed at the same time. 
     Further, the first and second speed-change assemblies  20 ,  30  may fulfill increase or decrease of speed by means of gear ratios between the first planet group  22 , the second planet group  23 , and the third planet group  32  with respect to the first sun gear  24 , the second sun gear  27 , and the third sun gear  28  respectively. For example, the first speed-change assembly  20  may be assumed for a high-speed operation, while the second speed-change assembly  30  is set for a mode of low-speed operation, or alternatively, the first speed-change assembly  20  is set for low-speed operation, while the second speed-change assembly  30  assumes a mode for high-speed operation. 
     In this way, the two-stage speed-change output device that features a small amount of occupied space and exhibiting same direction output and speed changing is constructed. 
     In a practical operation of the two-stage speed-change output device according to the present invention as being applied to the wheel hub assembly  50  of the electric vehicle, as shown in  FIG.  2   , the counterclockwise direction is taken as the backward or reverse direction, while the clockwise direction is set as the forward direction. Observing in a direction from the right side, when the motor assembly  10  drives the input sleeve  11  in the backward direction, the input sleeve  11  simultaneously drives the first carrier frame  21  of the first speed-change assembly  20  to rotate in the backward direction. Since the first sun gear  24  is fixed, in an immobile manner, on the main axle  100 , the first planet group  22  of the first carrier frame  21  rotates (orbits) around the first sun gear  24  in the backward direction, and each of the first planets  220  rotates (spins) synchronously in the backward direction (as shown in  FIG.  7   ). Since each individual one of the first planets  220  of the first planet group  22  and each corresponding one of the second planets  230  of the second planet group  23  are fixed together, the second planet group  23  and each of the second planets  230  are also forced to rotate (orbit) in the backward direction and rotating (spinning) in the backward direction, so that each of the second planets  230  of the second planet group  23  synchronously drives the second sun gear  27  of the transmission wheel disc  26  that is rotatably mounted on the input sleeve  11  to rotate in the forward direction (as shown in  FIG.  8   ), thereby making the transmission wheel disc  26  synchronously drive the first shell  25  that is fit to the outer circumference of the first carrier frame  21  to rotate in the forward direction. Since the first one-way clutching element  29  mounted on the first shell  25  is operating in the forward direction, the first shell  25  drives, by means of the first one-way clutching element  29 , the output shell  40  to do outputting in the forward direction (as shown in  FIG.  9   ). Further, since the first and second wheel hub shells  51 ,  52  and the internal wheel hub shell  55  of the wheel hub assembly  50  are fastened to the output shell  40 , the purpose of driving the wheel of the electric vehicle to rotate can be achieved by means of driving the wheel hub assembly  50 . Also, the transmission wheel disc  26  that is caused to rotate in the forward direction makes the third sun gear  28  arranged thereon to synchronously rotate in the forward direction, so that each of the third planets  320  of the third planet group  32  that is in mating engagement with the third sun gear  28  is caused to synchronously rotate (spin) in the backward direction. Since each of the third planets  320  of the third planet group  32  is in mating engagement with the internal ring toothed section  331  of the second shell  33  of the second speed-change assembly  30 , a power is developed for intending to drive the second carrier frame  31  of the third planet group  32  to rotate in the forward direction, yet due to the second carrier frame  31  being fit to the internal motor housing  14  of the motor assembly  10  by means of the third one-way clutching element  35  that is operable in the forward direction (and thus becoming fixed in this case), the second carrier frame  31  is kept fixed by the internal motor housing  14  in an immobile condition, so that each of the third planets  320  of the third planet group  32  is rotating in the backward direction and synchronously driving the second shell  33  to rotate in the backward direction (as shown in  FIG.  10   ). Since the second one-way clutching element  34  that is mounted to the second shell  33  is operable in the forward direction, the second shell  33  rotating in the backward direction become freewheeling or idle-rotating with respect to the output shell  40  by means of the second one-way clutching element  34 . Thus, when the motor assembly  10  drives the input sleeve  11  to rotate in the backward direction, it is only the first speed-change assembly  20  that drives the output shell  40 , while the second speed-change assembly  30  is set in an idling, and thus non-driving, condition. 
     When the motor assembly  10  drives the input sleeve  11  to rotate in the forward direction, the input sleeve  11  synchronously drives the first carrier frame  21  of the first speed-change assembly  20  to rotate in the forward direction. Since the first sun gear  24  is fixed, in an immobile condition, on the main axle  100 , the first planet group  22  of the first carrier frame  21  is caused to rotate (orbit) around the first sun gear  24  in the forward direction, and each of the first planets  220  synchronously rotates (spins) in the forward direction. Since each individual one of the first planets  220  of the first planet group  22  and each corresponding one of the second planets  230  of the second planet group  23  are fixed together, the second planet group  23  and each of the second planets  230  are also caused to orbit in the forward direction and spinning in the forward direction, so that each of the second planets  230  of the second planet group  23  synchronously drives the second sun gear  27  of the transmission wheel disc  26  that is rotatably mounted on the input sleeve  11  to rotate in the backward direction, making the transmission wheel disc  26  synchronously drive the first shell  25  that is rotatably fit to the outer circumference of the first carrier frame  21  to rotate in the backward direction. Since the first one-way clutching element  29  that is fit to the first shell  25  is operable in the forward direction, the first shell  25  rotating in the backward direction becomes freewheeling or idle-rotating with respect to the output shell  40  by means of the first one-way clutching element  29 . Also, the third sun gear  28  that is arranged on the transmission wheel disc  26  that is rotating in the backward direction is caused to synchronously rotate in the backward direction, so that each of the third planets  320  of the third planet group  32  that is in mating engagement with the third sun gear  28  is caused to synchronously rotate (spin) in the forward direction. Since each individual one of the third planets  320  of the third planet group  32  is in mating engagement with the internal ring toothed section  33  of the second shell  331  of the second speed-change assembly  30 , assuming a power-outputting condition, so as to drive the second carrier frame  31  on which the third planet group  32  is arranged to rotate in the forward direction. However, since the second carrier frame  31  is fit to the internal motor housing  14  of the motor assembly  10  by means of the third one-way clutching element  35  that is operable in the forward direction (and thus becoming fixed in this case), the second carrier frame  31  is kept fixed by the internal motor housing  14  in an immobile condition, so that each of the third planets  320  of the third planet group  32  synchronously drives the second shell  33  to rotate in the forward direction. Since the second one-way clutching element  34  that is mounted to the second shell  33  is operable in the forward direction, the second shell  33  rotating in the forward direction drives, by means of the second one-way clutching element  34 , the output shell  40  to rotate and output in the forward direction. Further, since the first and second wheel hub shells  51 ,  52  and the internal wheel hub shell  55  of the wheel hub assembly  50  and the output shell  40  are fastened together, the purpose of driving the wheel of the electric vehicle to rotate can be achieved by means of driving the wheel hub assembly  50 . Thus, when the motor assembly  10  drives the input sleeve  11  to rotate in the forward direction, it is only the second speed-change assembly  30  that drives the output shell  40 , while the first speed-change assembly  20  is set in an idling, and thus non-driving, condition. 
     When the electric vehicle is backed up and moving reversely, as shown in  FIGS.  2  and  7 - 10   , the wheel is caused by a frictional force thereof with respect to a road surface to force the wheel hub assembly  50  to rotate in the backward direction, and therefore, the first and second wheel hub shells  51 ,  52  of the wheel hub assembly  50  drives the output shell  40  to rotate in the backward direction. Since the first and second one-way clutching elements  29 ,  34  of the first and second speed-change assemblies  20 ,  30  that are mounted to an inner circumference of the output shell  40  are both a one-way clutching element that is of an arrangement that, considering transmission in a direction from inside toward outside, is operable in the forward direction and idling in the backward direction, so that when the output shell  40  rotates backward, as being transmitted reversely from outside to inside, the first and second one-way clutching elements  29 ,  34  oppositely drive, in the backward direction, the first shell  25  of the first speed-change assembly  20  and the second shell  33  of the second speed-change assembly  30  respectively corresponding thereto to rotate in the backward direction, wherein the first shell  25  of the first speed-change assembly  20  that rotates in the backward direction synchronously drives the transmission wheel disc  26  and thus the third sun gear  28  to rotate in the backward direction, therefore driving each of the third planets  320  of the third planet group  32  in mating engagement therewith to rotate (spin) in the forward direction; and the second shell  33  of the second speed-change assembly  30  that is also rotating in the backward direction drives each of the third planets  320  of the third planet group  32  in mating engagement with the internal ring toothed section  331  thereof to rotate (spin) in the backward direction, and therefore, a situation of immobility is developed due to the operations of the two are in opposite directions, this making it impossible for the electric vehicle to back up. Since each of the third planets  320  of the third planet group  32  is mounted on the second carrier frame  31  and since the second carrier frame  31  is fit to the internal motor housing  14  of the motor assembly  10  by means of the third one-way clutching element  35 , so that the second carrier frame  31  is set in a fixed, immobile condition in the forward direction, yet freewheeling or idle-rotating in the backward direction. This makes the second carrier frame  31  unidirectionally rotatable, and not affected by the third planets  320  of the third planet group  32  being fixed, and thus, driving through two-stage speed-change output of power is achievable and the electric vehicle is allowed to back up. 
     By means of the arrangement and description provided above, the motor assembly  10  of the two-stage speed-change output device according to the present invention may make use of rotation in either the backward direction or the forward direction to respectively drive the first and second speed-change assemblies  20 ,  30 , so as to make the first and second speed-change assemblies  20 ,  30  respectively drive the first and second one-way clutching elements  29 ,  34  to drive the output shell  40  in the same direction, allowing the two-stage speed-change output device of the present invention to be operable for switching with two stages of speed change by using the forward and backward rotations of the motor assembly  10 , exhibiting advantages of being easy to operate, occupying a relatively small amount of space, and being applicable to driving and speed changing for a small-sized electric vehicle, and thus practical utilization thereof can be greatly enhanced.