Shift by wire transmission shift control system
View Patent ↗A gear shift control system may include an output mechanism, first and second drive members and a drivetrain. The first drive member may be coupled to the output mechanism to drive the output mechanism and cause a transmission shift. The drivetrain includes a first input driven by the drive member during a first mode of operation and an output coupled to both the first input and the output mechanism to drive the output mechanism as commanded by the drive member. During a second mode of operation a second input is coupled to the output and a second drive member is coupled to the second input to drive the output mechanism through the second input and the output to cause a transmission gear shift. The second drive member may be laterally offset from the drivetrain and axially positioned within an axial height of the drivetrain.
1. A gear shift control system, comprising:
a first drive member including an electric motor;
an output shaft coupled to a vehicle transmission and to the first drive member to be driven for rotation by the first drive member;
a planetary gear set coupled to the first drive member and the output shaft, and having three intermeshed gear elements including a ring gear, a sun gear and at least one planet gear, where a first gear element, which is a first one of the intermeshed gear elements, is coupled to the first drive member and is driven for rotation by the first drive member, and a second gear element, which is a second one of the intermeshed gear elements, is coupled to the output shaft for rotation with the output shaft;
a return spring coupled to a third gear element, which is a third one of the intermeshed gear elements and which rotates about an axis, to drive the output shaft through the third gear element and the second gear element, wherein the return spring is radially outboard from and does not radially overlap the third gear element and wherein during a first mode of operation the transmission is shifted between park and other gears by causing the first drive member to rotate the output shaft through the second gear element and the first gear element when a transmission gear shift is desired, and during a second mode of operation, the transmission is shifted to park by the return spring which drives the output shaft through the third gear element and second gear element; and
a coupler having a first portion coupled to the return spring and a second portion coupled to the third gear element to connect the return spring to the third gear element, and wherein the coupler is not connected to anything other than the return spring and the third gear element.
2. The system of claim 1 wherein the return spring is a torsion spring with a first portion fixed against movement and a second portion coupled to the third gear element to provide a force on the third gear element to rotate the third gear element during the second mode of operation, and which also comprises a retainer including another torsion spring coupled to the third gear element to prevent rotation of the third gear element during the first mode of operation and permit rotation of the third gear element during the second mode of operation.
3. The system of claim 2 which also comprises a release mechanism that moves the second portion of the return spring during the second mode of operation.
4. The system of claim 3 which also comprises a power storage device coupled to the release mechanism and which stores a reserve of electrical power that is used to actuate the release mechanism.
5. The system of claim 4 wherein the power storage device includes a capacitor that stores a charge that may be provided to the release mechanism.
6. The system of claim 1 wherein the second portion of the coupler remains coupled to the same portion of the third gear element throughout movement of the third gear element.
7. The system of claim 6 wherein the third gear element includes a radially outwardly extending flange and wherein the second portion is coupled to the flange.