Spindle bearing arrangement for a power tool

Abstract

A power tool that includes a housing, a motor, a pair of motor bearings, a transmission, an output spindle and front and rear spindle bearings. The motor is received in the housing and includes a stator and an output shaft that extends through the stator. The motor bearings support the output shaft for rotation relative to the housing and are disposed on opposite ends of the stator. The transmission is driven by the motor and includes an input pinion that is mounted to the output shaft for rotation therewith. The output spindle is driven by the transmission. The front spindle bearing is mounted to a front end of the output shaft radially between the housing and the output shaft. The rear spindle bearing is mounted to a rear end of the output spindle and a portion of the rear spindle bearing rotates with the output shaft.

What is claimed is: 
     
       1. A power tool comprising:
 a housing; 
 a motor received in the housing, the motor having a stator and an output shaft that extends through the stator; 
 a pair of motor bearings supporting the output shaft for rotation relative to the housing about an axis, the motor bearings being disposed on opposite ends of the stator; 
 a transmission driven by the motor, the transmission having an input pinion that is mounted to the output shaft for rotation therewith; 
 an output spindle driven by the transmission for rotation about the axis; 
 a front spindle bearing mounted to a front end of the output spindle radially between the housing and the output spindle; and 
 a rear spindle bearing mounted to a rear end of the output spindle, wherein a portion of the rear spindle bearing engages and rotates with the output shaft. 
 
     
     
       2. The power tool of  claim 1 , wherein the output shaft extends through the input pinion. 
     
     
       3. The power tool of  claim 2 , wherein the rear spindle bearing is received in an aperture formed in the rear end of the output spindle. 
     
     
       4. The power tool of  claim 1 , wherein the rear spindle bearing is at least partly received in the input pinion. 
     
     
       5. The power tool of  claim 1 , wherein the rear spindle bearing is mounted on the input pinion. 
     
     
       6. The power tool of  claim 1 , wherein the front end of the output spindle has a first diameter, wherein the rear end of the output spindle has a second diameter, and wherein the first diameter is greater than the second diameter. 
     
     
       7. The power tool of  claim 1 , further comprising a clutch assembly that is configured to limit torque transmission through the transmission to the output spindle. 
     
     
       8. The power tool of  claim 1 , wherein the transmission is a multi-stage planetary transmission having an output stage with a planet carrier, and wherein the output spindle is coupled to the planet carrier for rotation therewith. 
     
     
       9. A power tool comprising:
 a housing; 
 a motor received in the housing, the motor having an output shaft configured to rotate about an axis; 
 a transmission driven by the motor, the transmission having an input pinion that is mounted to the output shaft for rotation therewith; 
 an output spindle driven by the transmission for rotation about the axis; 
 a front spindle bearing mounted to a front end of the output shaft radially between the housing and the output spindle; and 
 a rear spindle bearing mounted to a rear end of the output spindle, wherein the rear spindle bearing engages and is supported by the output shaft. 
 
     
     
       10. The power tool of  claim 9 , wherein the rear spindle bearing is directly mounted to the rear output spindle. 
     
     
       11. The power tool of  claim 9 , wherein the output shaft extends through the input pinion. 
     
     
       12. The power tool of  claim 9 , wherein the rear spindle bearing is directly mounted to the input pinion. 
     
     
       13. The power tool of  claim 12 , wherein the rear spindle bearing is received in an aperture formed in the input pinion. 
     
     
       14. The power tool of  claim 9 , further comprising a clutch assembly that is configured to limit torque transmission through the transmission to the output spindle. 
     
     
       15. The power tool of  claim 9 , wherein the transmission is a multi-stage planetary transmission having an output stage with a planet carrier, and wherein the output spindle is coupled to the planet carrier for rotation therewith. 
     
     
       16. A power tool comprising:
 a housing; 
 a motor received in the housing, the motor having a stator and an output shaft that extends through the stator; 
 a pair of motor bearings supporting the output shaft for rotation relative to the housing about an axis, the motor bearings being disposed on opposite ends of the stator; 
 a transmission driven by the motor, the transmission having an input pinion that is mounted to the output shaft for rotation therewith; 
 an output spindle driven by the transmission for rotation about the axis; 
 a front spindle bearing mounted to a front end of the output spindle radially between the housing and the output spindle; and 
 a rear spindle bearing mounted to a rear end of the output spindle, wherein the rear spindle bearing is not directly mounted to the housing and engages the output shaft. 
 
     
     
       17. The power tool of  claim 16 , wherein the rear spindle bearing is mounted to an element of the transmission such that the rear spindle bearing is disposed radially between the element of the transmission and the rear end of the output spindle. 
     
     
       18. The power tool of  claim 17 , wherein the element of the transmission is the input pinion. 
     
     
       19. The power tool of  claim 16 , wherein the output shaft extends through the input pinion. 
     
     
       20. The power tool of  claim 16 , wherein the rear spindle bearing is mounted to the output shaft such that the rear spindle bearing is disposed radially between the rear end of the output spindle and the output shaft.