Note: your issue is probably related to one of the two radial bearings (text colored in blue) below. Either a bearing has become loose and the spindle is allowed more movement because the bearing has moved, or one of the bearings is failing allowing side load movement. In either case the problem will not correct itself. It would appear that bearing #44 is press fit into the housing and that bearing 46 is part of an assembly that is pressed and retained when the crank arm is attached.
Silly question....did you check to see if a crank arm might be loose?
Here's a link to a patent specific to the motor and bike in question:
http://www.google.com/patents/US6629574
Click on Fig. 3, see detail #44 and #46. These are radial bearings that support both ends of the crank shaft.
Motor assembly
28 includes a number of components which are coaxial with a main spindle
42.
Further, main spindle 42 is also coaxial with the bottom bracket of the bicycle frame. Main spindle 42 which passes through the entire motor assembly, and is supported by left and right spindle bearings 44 and 46, respectively. (See FIG. 3.) The outside diameter of
left spindle bearing 44 is mounted to a main housing 48. Main housing
48 is employed to house most of the components of the motor assembly and conveniently fits within the bottom bracket of the bicycle as previously described.
Right spindle bearing 46 is mounted in an output driver 50. Coupled to main spindle
42 is a left crank arm
52 and a right crank arm
54. Crank arms
52 and
54 are coupled to spindle
42 with a tapered positive engagement and by the use of screws
56 which are screwed into threaded slots
58 in main spindle
42.
Motor assembly
28 further includes a motor rotor assembly
60 which is mounted to the outside diameter of rotor ball bearings
62. (See FIG. 3.) A motor magnet
64 is fixed to motor rotor assembly
60. The inner diameter of rotor ball bearings
62 are mounted on spindle
42. Motor rotor assembly
60 is free to rotate independent of spindle
42 as well as crank armns
52 and
54 which are mounted to spindle
42. A motor stator
66 is fixed to main housing
48. A plurality of motor control wires
68 exit through main housing
48. A circuit board
70 (see FIG. 3) having position sensing devices is mounted to a left side of main housing
48.
A first planet sun gear
72 is mounted directly to the right side of motor rotor assembly
60. The outer diameter of first planet sun gear
72 is meshed with three first planet gears
74. The three first planet gears
74 are mounted on ball bearings
76. The inner diameter of ball bearings
76 are mounted to shafts
78. The ends of shaft
78 are mounted to the flange of a second sun gear
80.
The outside diameter of second sun gear
80 is meshed with three second planet gears
82. Second sun gear
80 is supported on spindle
42 by bearings
84. The outer diameters of first planet gears
74 and second planet gears
82 are meshed with a ring gear
86. Ring gear
86 is machined directly into main housing
48. The inner diameters of the second planet gears
82 are mounted to ball bearings
88. (See FIG. 3.) The inner diameter of ball bearings
88 are mounted to shafts
90. Shafts
90 are attached to a motor output driver ring
92. Motor output driver ring
92 is supported by the inner diameter of bearing
94 as also shown in FIG.
4. The outer diameter of bearing
94 is mounted to a housing end cap
96.
