| 摘要 |
PROBLEM TO BE SOLVED: To secure the transmission efficiency of a friction roller type speed reducer 3a installed in a route for transmitting a power from a starter motor to an engine, and prevent the starter from being seized. SOLUTION: Where the maximum value of the peripheral velocity of a drive side cylindrical surface 42 in use is Umax (m/sec) and the average value of the contact pressure of an outer diameter side contact part 50b of a wedge roller 25 based on the preload of a compression coil spring 45 is Pmean (GPa), the requirement of the expression below is satisfied. Pmean > (Umax )<1/2> )/9 or Pmean >0.3 (GPa). With this constitution, a remarkable slip is prevented from occurring also on the inner diameter and outer diameter side contact parts 49a, 49b, 50a, and 50b during low load operation. |
