Machine element or mechanism – Rotary member or shaft indexing – e.g. – tool or work turret – Preselected indexed position
Patent
1986-11-28
1988-10-11
Wright, Dirk
Machine element or mechanism
Rotary member or shaft indexing, e.g., tool or work turret
Preselected indexed position
74335, B60K 4118, B60K 4110
Patent
active
047762390
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a semiautomatic transmission for vehicles, construction machines and similar, which semiautomatic transmission comprises a synchro-mesh transmission, which has an electrically controlled gear shift mechanism, a sensor for measuring the engine torque, and sensors for measuring the rotating speeds of drive line shafts located immediately before the transmission or after the transmission, which sensors transmit signals corresponding to measured quantities to the electric control unit for selecting a gear suiting the actual driving situation.
Semiautomatic transmissions are known in the prior art, and they are widely used in the drive line systems of motor vehicles and similar equipment. Conventional semiautomatic transmissions are arranged in such a way that the clutch and the transmission are specially designed in order to make the clutch pedal or similar unnecessary. On the other hand, these systems have a normal gear shift selector for selecting the desired driving gear. In these systems the clutch and the transmission must be specially designed, and the clutch is usually a kind of centrifugal clutch by which the engagement of the drive line depends on the engine speed of revolutions. Usually there is also a torque converter between the clutch and the transmission for evening up the jerks due to the engagement of the gear thus protecting the transmission. From the point of view of the driver, a conventional system such as this, when installed for instance in a vehicle, differs from a usual manual transmission only in that the clutch pedal has been omitted or that it is not necessary to use the clutch pedal when shifting the gear. Therefore it is the driver of the vehicle who always selects the desired driving gear. Thus the driver must concentrate on the selection of the gear and distract his attention from the actual driving.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a new type of semiautomatic transmission, which eliminates the drawbacks prevalent in the solutions of the prior art. A characteristic feature of the invention is that the transmission is connected with the rest of the drive line with an overrunning clutch and that the engaging circuit of the transmission is an electric power circuit that is opened and closed by means of the accelerator pedal of the engine or with a similar power regulator.
According to the embodiment of the invention the overrunning clutch may engage in both rotating directions (a bidirectionally engaging overrunning clutch), and it is installed between the output shaft of the transmission and the drive shaft, with which the power is transmitted to the driver gear, in order to connect these shafts together, and that said sensors measuring the rotating speeds are installed on the output shaft of the transmission and on the drive shaft for measuring their rotating speeds.
An essential feature of this embodiment is that the electric power circuit of the transmission is arranged to be closed when the rotating speeds of the output shaft of the transmission and the drive shaft differ, in other words when the accelerator pedal is lifted up and the engine power has been essentially reduced, or when the speed of the vehicle, i.e. the rotating speed of the drive shaft is zero, and that at other times said electric power circuit is arranged to be open.
According to another embodiment of the invention, the overrunning clutch is installed between the clutch shaft and the input shaft of the transmission to connect said shafts with each other, and that said sensors measuring the rotating speeds are installed onto the clutch shaft and the input shaft of the transmission to measure the rotating speeds of these shafts.
It is characteristic to this second embodiment of the invention that the electric power circuit of the transmission is arranged to be closed when the rotating speeds of the clutch shaft and the input shaft of the transmission differ, in other words when the accelerator pedal is lif
REFERENCES:
patent: 4485443 (1984-11-01), Kuodler et al.
patent: 4616521 (1986-10-01), Akashi et al.
patent: 4621545 (1986-11-01), Mohl
Sassi Kari
Tammisto Erkki
Konejukka Oy
Wright Dirk
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