Abstract:
Friction-reducing bearings on the front and rear axles of a radio controlled, toy vehicle enable smooth driving of the vehicle, even at high speeds. Each bearing includes an annular track in which a plurality of freely revolving, hard metal balls is contained.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention generally relates to radio controlled, toy vehicles having front and rear wheels whose movements are controlled by radio frequency signals generated by a wireless transmitter remote from the vehicle and, more particularly, to a wheel bearing system for reducing friction on the axles on which the wheels are mounted, especially during high speed motion of the vehicle. 
     2. Description of the Related Art 
     Radio controlled, toy vehicles have on-board antennas for receiving radio frequency control signals generated by antennas on hand-held, wireless transmitters. The control signals include drive signals for moving the vehicle forward or backward, and steering signals for moving the vehicle toward the right or left during either forward or backward movement. The control signals are processed by on-board control circuitry to activate on-board DC motors. Transmissions and gear boxes are employed for transmitting the mechanical energy produced by the motors to the wheels. High gear ratios for the gear boxes enable the vehicles to move at relatively high speeds, thereby increasing the entertainment value of such vehicles. 
     High speed operation of such vehicles, however, causes the rear axles on which the rear wheels are mounted, and the front axles on which the front wheels are mounted, to vibrate and shake, thereby causing the vehicles to not run smoothly even over smooth surfaces. U.S. Pat. No. 3,473,259 is an example of a toy vehicle wheel and journal bearing construction. 
     OBJECTS OF THE INVENTION 
     Accordingly, it is a general object of this invention to enable radio controlled, toy vehicles to be driven smoothly at high speeds. 
     More particularly, it is an object of the present invention to reduce friction on the rear and front axles of such toy vehicles. 
     It is another object of this invention to resist vibrations and shaking of the rear and front axles during high speed movement of such vehicles. 
     SUMMARY OF THE INVENTION 
     In keeping with the above objects and others which will become apparent hereafter, one feature of the present invention resides, briefly stated, in a wheel bearing system for a high speed, radio controlled toy vehicle having front and rear wheels whose movements are controlled by radio frequency signals generated by a wireless transmitter remote from the vehicle. 
     The system comprises an on-board, rear casing having a pair of tubular extensions extending in opposite directions along a rear axis, and a pair of abutment walls. Each abutment wall is located within a respective extension and extends along a transverse axis generally perpendicular to the rear axis. 
     The system also includes a pair of apertured, annular, first track elements. Each first track element is mounted within a respective extension and abuts against a respective abutment wall. A pair of drive axles is mounted on the rear casing and extends in opposite directions along the rear axis for driving the rear wheels. Each drive axle extends with clearance through a respective first track element and has an outer shaft portion that extends beyond a respective extension. A pair of rear rims supports the rear wheels. Each rear rim is mounted on a respective outer shaft portion. 
     The system further includes a pair of annular, second track elements. Each second track element is mounted within a respective extension and is in force-transmitting engagement with a respective rear axle. Each second track element within a respective extension bounds an annular track with a respective first track element within the respective extension. 
     In accordance with this invention, a plurality of freely revolving, rigid balls is mounted within a respective track and rollably bears against the respective first and second track elements that bound the respective track, for reducing friction on the rear axles during high speed motion of the toy vehicle. 
     In the preferred embodiment, each outer shaft portion has an end bore. A pin extends through a respective rear rim and into the bore of a respective outer shaft portion. 
     Also, in the preferred embodiment, each first track element has a transverse base portion that engages the respective abutment wall, and a skirt portion that extends along the rear axis within the respective extension. Each second track element has an axial part that engages the respective rear axle, and a transverse part that extends along the transverse axis away from the respective axial part. The balls simultaneously engage the transverse base portion, the skirt portion, the axial part and the transverse part of the track elements. Each drive axle has a polygonal section within the respective extension. Each second track element has a polygonal aperture of complementary contour to the polygonal section of the respective rear axle. 
     As for the front wheels, the system further comprises a pair of front rims for supporting the front wheels. Each front rim has a tubular hub. A pair of front axles is mounted on the vehicle. Each front axle extends through a respective hub along a front axis. 
     In the preferred embodiment, each hub includes a blind bore having an apertured side wall which extends transversely of the front axis, and an apertured disc which is spaced axially from the bottom wall to bound a compartment within the hub. A pair of apertured, annular, first track members is mounted within each compartment. One of the first track members abuts against the side wall. The other of the first track members abuts against the disc. Each front axle extends with clearance through the disc, the track members and the side wall of each hub. 
     The preferred embodiment further comprises an apertured, annular, second track member which is mounted in each hub between the pair of first track members. The second track member has a first set of wall sections which bounds a first annular channel with said one of the first track members, and a second set of wall sections which bounds a second annular channel with said other of the first track members. Each front axle extends with clearance through the second track member. 
     In accordance with another feature of this invention, two groups of freely revolving, rigid balls are provided. Each group is mounted within a respective channel and rollably bears against the respective first and second track members that bound the respective channel, for reducing friction on the front axles during high speed motion of the toy vehicle. 
     The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a radio controlled, toy vehicle controlled by a hand-held remote transmitter and equipped with a wheel bearing system in accordance with this invention; 
     FIG. 2 a bottom plan view of the vehicle of FIG. 1; 
     FIG. 3 is a sectional view taken on line  3 — 3  of FIG. 2; and 
     FIG. 4 is a sectional view taken on line  4 — 4  of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, reference numeral  10  in FIG. 1 generally identifies a radio controlled, battery-powered toy vehicle having rear wheels  12  and front wheels  14  whose movements are controlled by radio frequency control signals generated by a hand-held, battery-powered, transmitter  16  and broadcast by a transmitter antenna  18  to a receiver antenna  20  mounted on the vehicle  10 . The control signals include drive signals for moving the vehicle forward or backward, and steering signals for moving the vehicle toward the right or left during the forward or backward movement. 
     A rear casing  22  is mounted at the rear of the vehicle between the rear wheels  12 . The casing  22  has a central gear box  24  and a pair of tubular housing extensions  26 ,  28  extending in opposite directions along a rear axis  20  (see FIG.  3 ). Casing  22  also has an offset motor compartment  32  in which a reversible DC motor is mounted. The motor has a rotary drive shaft coupled to a gear train in the gear box. In turn, the gear train is coupled to a pair of rear drive axles  34  (only one shown in FIG. 3) which are mounted on the extensions  26 ,  28  and extend in opposite directions along the rear axis  30 . 
     When drive signals are received by the receiver antenna  20 , the drive signals are processed by a control circuit, and output drive signals are conveyed to the motor to turn its output drive shaft in a selected circumferential direction and at a selected rate of rotation. In turn, the motion of the drive shaft is transmitted through the gears to the rear axles  34  for turning the rear wheels  12 . The ratio of the gears is made manually selectable for both low and high running speeds. 
     When steering signals are received by the receiver antenna  20 , the steering signals are processed by the control circuit, and output steering signals are conveyed to the motor and, in turn, to operate a steering linkage having opposite rods  36  (only one shown in FIG.  4 ). The rods  36  are pivotably coupled to a pair of steering arms  38  having cylindrical sections  40  in which a pair of front axles  42  are fixedly mounted for joint movement with the arms  38 . The front wheels  14  are mounted on the front axles  42 . The linkage is operated to swing the rods  36  toward the right or the left through a desired angular distance, thereby jointly moving the arms  38  and the front axles  42  for steering the front wheels. 
     In accordance with this invention, a wheel bearing system is provided for reducing the friction and vibration on the front axles  42  and the rear axles  34 . As best seen in FIG. 3, the system includes, for each rear wheel  12 , a centrally apertured, abutment wall  44  located within the extension  26  and extending in a plane perpendicularly of the rear axis  30 . A centrally apertured, first track element  46  is mounted within each extension  26  and has a transverse base portion  48  engaging the abutment wall  44 , and an axial annular skirt portion  50  engaging an inner, axial, annular surface of the extension  26 . 
     A centrally apertured, second track element  52  is also mounted within each extension  26  and has an axial part  54  engaging a respective rear axle  34 , and an annular transverse part  56  extending perpendicularly to the axial part. The base portion  48  and the transverse part  56  face each other, lie in mutual parallelism and are axially spaced apart by a predetermined axial distance. The skirt portion  50  and the axial part  54  also face each other, lie in mutual parallelism and are radially spaced apart by a predetermined radial distance. The base portion  48 , skirt portion  50 , transverse part  56  and axial part  54  together bound an annular track within the extension. The second track element also has a radial annular lip  58  that engages the inner surface of the extension and seals the track from the entry of contaminants, such as moisture and dust. 
     Each rear axle  34  has an inner coupling portion  60  which is coupled in a force-transmitting relationship with the transmission. Each rear axle  34  extends with clearance through the abutment wall  44  and the base portion  48  of the first track element  46 . Each rear axle  34  drivingly engages the second track element  52  by configuring a central aperture of the second track element with a polygonal outline, and by configuring an outer peripheral surface of an intermediate portion  62  of the rear axle  34  with a complementary contour. Each rear axle  34  has an outer shaft portion  64  which extends into a tubular hub  66  of a rear rim  68  on which a rubber tire  70  of the rear wheel  12  is mounted. A pin  72  is press-fitted into a bore  74  at the outer shaft portion  64  to retain the rear rim  68  on the rear axle  34 . 
     A plurality of freely revolving, rigid balls  76 , preferably constituted of metal, is provided within each annular track. The balls  76  rollably bear against the base portion  48 , skirt portion  50 , axial part  54  and transverse part  56 . The first and second track elements are also preferably constituted of metal. The balls  76  reduce the friction on each rear axle  34  as it rotates and drives the rear wheels  12 . 
     The wheel bearing system includes, for each front wheel  14 , a centrally apertured disc  78  mounted at an axial end of a tubular hub  80  of a front rim  82  for each front wheel  14 . The hub  80  has an apertured side wall  90  through which each front axle  42  extends along a front axis  84 . An outer end of the front axle  42  has a head  86  to retain the front rim  82  axially adjacent the cylindrical section  40  in which an opposite inner end  92  of the front axle  42  is press-fitted. Preferably, the inner end  92  has axial splines. A rubber tire  94  is mounted on each front rim  82 . 
     Each disc  78  and side wall  90  are spaced axially apart to bound a compartment within the hub  80 . A pair of centrally apertured, first track members  100 ,  102  are mounted within each compartment in a mirror symmetrical relationship. First track members  100 ,  102  have radial base parts  104 ,  106  and axial skirt parts  108 ,  110 . 
     An apertured, second track member  112  is mounted within each compartment between a pair of first track members  100 ,  102 . The second track member  112  has a first set of wall sections, including an axial section  114  and a radial section  116 , that bound a first annular channel with the axial skirt part  108  and the radial base part  104 . The second track member  112  also has a second set of wall sections, including an axial section  118  and a radial section  120 , that bound a second annular channel with the axial skirt part  110  and the radial base part  106 . Each front axle  42  extends with clearance through the second track member  112 . 
     Two groups of freely revolving, rigid balls  122 ,  124 , preferably constituted of metal, are provided within the annular channels in each hub  80 . The balls  122 ,  124  rollably bear against the first and second track members that bound the respective channels. The first and second track members are also preferably constituted of metal. The balls  122 ,  124  reduce the friction on each front axle  42  as the front wheels  14  turn about the front axles, especially during high speed motion of the toy vehicle. 
     The speed at which the described vehicle can reach is higher than that for other radio controlled vehicles that do not have the wheel bearing system of this invention. 
     It will be understood that each of the elements described above, or two or more together, also may find a useful application in other types of constructions differing from the types described above. 
     While the invention has been illustrated and described as embodied in a wheel bearing system for high speed, radio controlled toy vehicles, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims. 
     What is claimed as new and desired to be protected by letters patent is set forth in the appended claims.