Patent ID: 8683927

Claim:
A wheel truck, comprising: a) a front wheel pair assembly ( 11 ) and a rear wheel pair assembly ( 11 ); b) two side frame assemblies ( 12 ), each side frame assembly ( 12 ) comprising a square box in a center and journal-box guides on two ends, and the journal-box guides being disposed on roller bearing adapters; c) two spring suspension devices ( 14 ), the two spring suspension devices being disposed in the square boxes of the two side frame assemblies ( 12 ), respectively; and d) a bolster assembly ( 15 ) comprising two ends which are disposed on the two spring suspension devices ( 14 ), respectively; wherein the bolster assembly ( 15 ) further comprises a pilot hole ( 15 a ) in a center and two mounting holes ( 15 b ) on the two ends, the pilot hole ( 15 a ) is rotationally matched with a cylindrical upper center plate ( 16 ) of a car body for transmitting vertical and horizontal forces from the car body, and the two mounting holes ( 15 b ) are disposed above the two spring suspension devices ( 14 ), respectively; each mounting hole ( 15 b ) receives a lower side bearing ( 13 ), and the lower side bearing ( 13 ) is matched with a corresponding upper side bearing ( 17 ) disposed on each side of the car body for transmitting the vertical load from the car body; the lower side bearing ( 13 ) comprises a first friction board ( 3 ), a second friction board ( 1 ), an inner pedestal ( 6 ), a bearing sleeve ( 4 ) sleeving the inner pedestal ( 6 ), a pressure block ( 2 ), and an elastic component ( 5 ); the pressure block ( 2 ) is disposed on an upper part of the inner pedestal ( 6 ), and the second friction board ( 1 ) is disposed on a top of the pressure block ( 2 ); the first friction board ( 3 ) is disposed on a top of the bearing sleeve ( 4 ); a friction coefficient of the first friction board ( 3 ) Î¼ k and a friction coefficient of the second friction board ( 1 ) Î¼ z meet the relation: Î¼ k >Î¼ z ; the elastic component ( 5 ) is disposed between the inner pedestal ( 6 ) and the bearing sleeve ( 4 ) for controlling a relative position of the inner pedestal ( 6 ) and the bearing sleeve ( 4 ); and a mechanical property of the elastic component ( 5 ) meets following requirements: a) in an empty loaded state, a level position of the first friction board ( 3 ) is higher than that of the second friction board ( 1 ) so that the first friction board bears the load of the car body; and b) in a heavy loaded state, the level position of the first friction board ( 3 ) is equal to that of the second friction board ( 1 ) so that the first friction board and the second friction board bear the load of the car body.