Method for controlling a gear shift in a transmission arrangement
AssigneeVolvo Construction Equipment AB
InventorsJan Dersjö, Per Mattsson, Johnny Arne
Life of this patent
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Abstract
A method is provided for controlling a gear shift from a forward gear to a reverse gear in a transmission arrangement, the method including the steps of: positioning a first locking mechanism and a first connecting mechanism at least in a partially engaged state for reducing a rotational speed of a planet carrier of a second planetary gear set; and positioning a second locking mechanism in an engaged state when a rotational speed of the planet carrier of the second planetary gear set is below a predetermined threshold limit.
Claims19
A method for controlling a gear shift from a forward gear to a reverse gear in a transmission arrangement, the transmission arrangement comprising a first, a second, a third, and a fourth planetary gear set comprising a sun gear, a planet carrier and a ring gear, respectively, wherein the transmission arrangement further comprises a transmission housing, an input shaft and an output shaft, wherein
- the planet carrier of the first planetary gear set is operatively connected to the output shaft of the transmission arrangement;
- the ring gear of the first planetary gear set and the planet carrier of the second planetary gear set are operatively connected to each other;
- the sun gear of the first planetary gear set and the sun gear of the second planetary gear set are operatively connected to each other;
- the ring gear of the second planetary gear set and the planet carrier of the third planetary gear set are operatively connected to each other;
- two of the sun gear, the planet carrier and the ring gear of the fourth planetary gear set are each operatively connected to a respective one of the input shaft, the sun gear, the planet carrier and the ring gear of the third planetary gear set;
- a first locking mechanism is arranged for selectively locking the ring gear of the third planetary gear set to the transmission housing;
- a second locking mechanism is arranged for selectively locking the planet carrier of the second planetary gear set to the transmission housing;
- and
- a first connecting mechanism is arranged for selectively connecting the planet carrier of the second planetary gear set to the ring gear of the third planetary gear set;
- the method comprising:
- positioning the first locking mechanism and the first connecting mechanism at least in a partially engaged state for reducing the rotational speed of the planet carrier of the second planetary gear set;
- and
- positioning the second locking mechanism in an engaged state when the rotational speed of the planet carrier of the second planetary gear set is below a predetermined threshold limit.
A control unit for controlling gear shift from a forward gear to a reverse gear in a transmission arrangement, the transmission arrangement comprising a first, a second, a third, and a fourth planetary gear set comprising a sun gear, a planet carrier and a ring gear, respectively, wherein the transmission arrangement further comprises a transmission housing, an input shaft and an output shaft, wherein
- the planet carrier of the first planetary gear set is operatively connected to the output shaft of the transmission arrangement;
- the ring gear of the first planetary gear set and the planet carrier of the second planetary gear set are operatively connected to each other;
- the sun gear of the first planetary gear set and the sun gear of the second planetary gear set are operatively connected to each other;
- the ring gear of the second planetary gear set and the planet carrier of the third planetary gear set are operatively connected to each other;
- two of the sun gear, the planet carrier and the ring gear of the fourth planetary gear set are each operatively connected to a respective one of the input shaft, the sun gear, the planet carrier and the ring gear of the third planetary gear set;
- a first locking mechanism is arranged for selectively locking the ring gear of the third planetary gear set to the transmission housing;
- a second locking mechanism is arranged for selectively locking the planet carrier of the second planetary gear set to the transmission housing;
- and
- a first connecting mechanism is arranged for selectively connecting the planet carrier of the second planetary gear set to the ring gear of the third planetary gear set;
- wherein the control unit is configured to:
- position the first locking mechanism and the first connecting mechanism at least in a partially engaged state for reducing the rotational speed of the planet carrier of the second planetary gear set;
- and
- position the second locking mechanism in an engaged state when the rotational speed of the planet carrier of the second planetary gear set is below a predetermined threshold limit.
Dependencies are inferred from the claim text.