Machine element or mechanism – Gearing – In series plural interchangeably locked nonplanetary units
Patent
1992-04-01
1993-10-05
Wright, Dirk
Machine element or mechanism
Gearing
In series plural interchangeably locked nonplanetary units
74335, 475134, F16H 302
Patent
active
052494810
DESCRIPTION:
BRIEF SUMMARY
This invention relates to planetary gear units and particularly, though not exclusively, to such units for use in tractor transmissions.
Co-pending UK patent application No. 9017921.9 of even date describes and claims a planetary gear unit which includes planetary trains and clutches which when operated in certain combinations provide a plurality of substantially evenly spaced but relatively closely grouped ratios. The planetary gear unit is designed to provide a multi-ratio powershift unit which is particularly suitable for use as the input stage of a tractor transmission for use with an additional gearbox.
It is an object of the present invention to provide a planetary gear unit of the type described in the above referred to co-pending UK patent application having a simple but efficient arrangement for the control of the operative ratio of the unit.
Thus according to the present invention there is provided a gear unit providing a plurality of operative ratios and having a plurality of fluid pressure operated ratio engaging clutches, the gear unit being characterised by the inclusion of: pressure operated clutch, pressure operated actuator, actuator connected downstream of the last valve in the series connection and at least one actuator connected between each valve of the series, valves so that by changing the operative condition of one valve at a time the operative ratio of the gear unit can be changed to the next adjacent ratio provided by the unit in a progressive manner throughout the entire ratio range of the unit.
In a planetary gear unit in accordance with the above referred to co-pending UK patent application when moving up and down the available ratios in ratio order it is necessary when changing between certain adjacent ratios to change the pressurization state of both clutches so that sequential changes up and down the full range of available ratios cannot be made by operation of the clutches in a true binary manner (that is it is not possible to change between all adjacent ratios by changing the pressurization state of only one clutch).
A gear unit in accordance with the present invention overcomes the above difficulty by enabling the pressurisation state of both clutches to be changed by the single act of changing the position of only one of the valves thus the control system can effectively be operated in a binary manner which greatly simplifies its control.
In a gear unit having first and second fluid pressure operated ratio engaging clutches two flow reversing valves are provided in series, the last valve in the series being a three-port valve and the other valve being a four-port valve.
The first fluid pressure operated clutch may be paired with a first spring-engaged clutch and the second fluid pressure operated clutch may be paired with a second spring-engaged clutch, the arrangement being such that when the pressure operated clutch of each respective pair is engaged, the spring-engaged clutch of the respective pair is automatically disengaged and vice versa providing four ratio engaging clutch conditions.
Such an arrangement could be arranged to provide a powershift capability allowing ratio changes under full power between all four ratios by simply controlling the pressurisation state of the first and second clutches.
In an alternative arrangement the gear unit includes an additional two ratio section in series with in the four ratio section, said additional two ratio section including a third fluid pressure operated clutch and a third spring-engaged clutch to engage the two additional ratios and a third flow reversing valve for the control of an actuator for the third fluid pressure operated clutch.
In one form of the above arrangement the actuator of the fluid pressure operated clutch of the additional two ratio section is connected downstream of the last valve in the series connection and the other two clutch actuators are connected one between the second and last valves and the other between the first and second valves respectively.
In another form of the above arrangement, one o
REFERENCES:
patent: 3708047 (1973-01-01), Kuhnle et al.
patent: 3799003 (1974-03-01), Van Dest
patent: 3863523 (1975-02-01), Starling et al.
patent: 3945265 (1976-03-01), Bell et al.
patent: 4246990 (1981-01-01), Strantz
patent: 4478106 (1984-10-01), Schreiner
patent: 4653352 (1987-03-01), Nakao et al.
patent: 4742731 (1988-05-01), Eldridge et al.
patent: 4876924 (1989-10-01), Fletcher et al.
patent: 4901600 (1990-02-01), Wilson
Massey-Ferguson Services N.V.
Wright Dirk
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