Motor bearing preloading system with plastic endbells configured to preload the bearing assemblies

A motor assembly comprising:

• a motor that drives an output shaft;
• a front endbell assembly fixed to a front end of the motor, the front endbell assembly including a plastic front endbell and a front bearing assembly through which a driving end of the output shaft extends, wherein the plastic front endbell is over-molded about the front bearing assembly and elasticity of the plastic front endbell operates to preload the front bearing assembly to restrict axial movement of the front bearing assembly;
• and
• a rear endbell assembly fixed to a rear end of the motor opposite from the front end, the rear endbell assembly including a plastic rear endbell and a rear bearing assembly into which a rear end of the output shaft extends, wherein the plastic rear endbell is over-molded about the rear bearing assembly and elasticity of the plastic rear endbell operates to preload the rear bearing assembly to restrict axial movement of the rear bearing assembly;
• wherein the front bearing assembly is configured as a front ball bearing including a front inner race and a front outer race that define a track that receives a front ball, and the plastic front endbell is over-molded about the front outer race to apply an inward preloading force to the front outer race, and wherein the elasticity of the plastic front endbell operates to hold the front outer race of the front bearing assembly to restrict axial movement of the front bearing outer race;
• wherein the rear bearing assembly is configured as a rear ball bearing including a rear inner race and a rear outer race that define a track that receives a rear ball, and the plastic rear endbell is over-molded about the rear outer race to apply an inward preloading force to the rear outer race oppositely from the preloading force applied to the front outer race, and wherein the elasticity of the plastic rear endbell operates to hold the rear outer race of the rear bearing assembly to restrict axial movement of the rear bearing outer race;
• and
• wherein the output shaft includes a shoulder that interacts against the front or rear inner race to apply an outward preloading force to said front or rear inner race oppositely from the preloading force applied to an opposing one of the outer races.

A motor assembly comprising:

• a motor that drives an output shaft;
• a front endbell assembly fixed to a front end of the motor, the front endbell assembly including a plastic front endbell and a front bearing assembly through which a driving end of the output shaft extends, wherein the plastic front endbell is over-molded about the front bearing assembly and elasticity of the plastic front endbell operates to preload the front bearing assembly to restrict axial movement of the front bearing assembly;
• and
• a rear endbell assembly fixed to a rear end of the motor opposite from the front end, the rear endbell assembly including a plastic rear endbell and a rear bearing assembly into which a rear end of the output shaft extends, wherein the plastic rear endbell is over-molded about the rear bearing assembly and elasticity of the plastic rear endbell operates to preload the rear bearing assembly to restrict axial movement of the rear bearing assembly;
• wherein the front bearing assembly is configured as a front ball bearing including a front inner race and a front outer race that define a track that receives a front ball, and the plastic front endbell is over-molded about the front outer race to apply an inward preloading force to the front outer race, and wherein the elasticity of the plastic front endbell operates to hold the front outer race of the front bearing assembly to restrict axial movement of the front bearing outer race;
• wherein the rear bearing assembly is configured as a rear ball bearing including a rear inner race and a rear outer race that define a track that receives a rear ball, and the plastic rear endbell is over-molded about the rear outer race to apply an inward preloading force to the rear outer race oppositely from the preloading force applied to the front outer race, and wherein the elasticity of the plastic rear endbell operates to hold the rear outer race of the rear bearing assembly to restrict axial movement of the rear bearing outer race;
• and
• wherein the output shaft includes a front shoulder that interacts against the front inner race to apply an outward preloading force to the front inner race oppositely from the preloading force applied to the front outer race.