Patent ID: 6286380
Filing Date: 2001-09-11
Classification: F16H,Y10T

Abstract:
An automatic speed-change apparatus for a gear transmission connected to a select and change speed pull-rod of the gear transmission having a constitution in which the select and change speed pull-rod is moved in an axial direction to select a line of a change speed fork provided within the gear transmission and a rotation direction of said select and change speed pull-rod cooperates with said change speed fork to complete speed change of a gear, for executing select and change speed operations of the gear transmission, said automatic speed-change apparatus comprising:a select mechanism for executing said select operation and a change speed mechanism for executing said change speed operation;said select mechanism comprises a select shaft rotated by a select motor capable of having a controlled clockwise and counter clockwise rotation, a select sensor provided on an outer end of the select shaft and detecting an operating angle of the select shaft in rotation direction, a select lever fixed to said select shaft and a connector connecting a tip end portion of the select lever to said select shaft;said change speed mechanism comprises a change speed motor capable of controlling forward and backward rotation;a plurality of intermediate shaft gear mechanisms each having a large diameter gear, a small diameter gear and an intermediate shaft parallel to the select and change speed pull-rod; a change speed gear engaged with the intermediate shaft gear mechanism to transmit rotation and fixed to said select and change speed pull-rod; and a change speed sensor provided on an outer end of said select and change speed rod and detecting an operating angle of the select and change speed pull-rod in the rotation direction;two pairs of a first intermediate shaft gear mechanism and a second intermediate shaft gear mechanism are provided in said change speed mechanism between an output shaft of said change speed motor and said select and change speed pull-rod to thereby constitute a first reduction gear mechanism, a second reduction gear mechanism and a third reduction gear mechanism from a change speed motor side in this order and a main body of said change speed motor is provided at said gear transmission side; said shift mechanism is provided with a small diameter change speed gear fixed to the output shaft of said change shaft motor and a large diameter change speed gear engaged with the small diameter gear of said second intermediate shaft gear mechanism to transmit rotation and fixed to said select and change speed pull-rod, said first intermediate shaft gear mechanism engaged with the small diameter change speed gear to transmit rotation and having a large diameter gear provided at a gear transmission side and a small diameter gear provided at an opposite side to the gear transmission, said second intermediate shaft gear mechanism engaged with the small diameter gear of said first intermediate shaft gear mechanism and having a large diameter gear at an opposite side to said gear transmission and a small diameter gear provided at said gear transmission side;a center distance of said first reduction gear mechanism is set slightly shorter than a center distance of said second reduction gear mechanism, the center distance of said second reduction gear mechanism is set equal to a center distance of said third reduction gear mechanism, the first, second and third reduction gear mechanisms have equal gear specifications, the numbers of gear teeth of the small diameter gears of the respective reduction gear mechanisms are the same, only the number of gear teeth of the large diameter gear of said first reduction gear mechanism is set so as not to interfere with the small diameter gear of said second reduction gear mechanism;during the select operation, when the select motor is actuated, said select shaft rotates in a direction to rock said select lever and to axially move said select and change speed pull-rod through said connector and said select shaft is adjusted by feedback control of said select sensor to thereby allow said select shaft to reach a predetermined select line; andduring the change speed operation, when the change speed motor is actuated, said change speed gear is rocked through said intermediate shaft gear mechanisms and said select and change speed pull-rod rotates in a direction and adjusted by feedback control of said change speed sensor to thereby allow the select and change speed pull-rod to reach a predetermined change speed line.