Microprocessor controlled neutral circuit for a power transmission
First Claim
1. A control system for a vehicle transmission of the type including a plurality of intermeshing gears and a plurality of clutches associated with the gears, the gears being coupled through an input shaft to a vehicle engine and through an output shaft to a driven axle, the clutches being engageable and disengageable in predetermined combinations to provide various drive gear ratios between the input shaft and the output shaft in response to control signals, the control system comprising:
- a plurality of actuator coils actuatable to selectively engage and disengage the clutches;
a coil enabling circuit including a switch for completing a current carrying path through the actuator coils and a relay coil for maintaining the switch in an actuator coil enabled position; and
a control circuit coupled to the coil enabling circuit, the control circuit selectively completing and interrupting a current path through the relay coil to control the position of the switch and thereby enable and disable the actuator coils.
3 Assignments
0 Petitions
Accused Products
Abstract
A control system is provided for selectively placing a vehicle transmission in a neutral condition after startup of the vehicle. The transmission is of the type including a plurality of intermeshing gears and associated clutches. The clutches are engageable and disengageable in predetermined combinations in response to energization and de-energization of actuator coils to establish predetermined gear ratios between input and output shafts of the transmission. The control system includes a neutral circuit and a control circuit. The neutral circuit causes a current carrying path through the coils to be interrupted under the control of the control circuit. The neutral circuit preferably also causes the transmission to be placed in a neutral condition upon startup of the vehicle engine. The control circuit preferably includes a microprocessor that monitors operating conditions of the vehicle and the control system and causes the neutral circuit to interrupt the current path through the coils upon detection of a system failure. The neutral circuit is configured to latch after startup of the vehicle in neutral and the control circuit causes interruption of power to the coils by removing a ground connection through a relay coil in the neutral circuit.
52 Citations
23 Claims
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1. A control system for a vehicle transmission of the type including a plurality of intermeshing gears and a plurality of clutches associated with the gears, the gears being coupled through an input shaft to a vehicle engine and through an output shaft to a driven axle, the clutches being engageable and disengageable in predetermined combinations to provide various drive gear ratios between the input shaft and the output shaft in response to control signals, the control system comprising:
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a plurality of actuator coils actuatable to selectively engage and disengage the clutches; a coil enabling circuit including a switch for completing a current carrying path through the actuator coils and a relay coil for maintaining the switch in an actuator coil enabled position; and a control circuit coupled to the coil enabling circuit, the control circuit selectively completing and interrupting a current path through the relay coil to control the position of the switch and thereby enable and disable the actuator coils. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a work vehicle, such as an agricultural tractor, a control system for selectively placing a transmission in a neutral state, the transmission being of the type including a plurality of intermeshing gears associated with a plurality of clutches, the clutches being engageable and disengageable in predetermined combinations by electrical energization and de-energization of actuator coils to establish predetermined forward and reverse gear ratios between a vehicle engine and a driven axle through the transmission, the control system comprising:
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a coil enabling circuit including a switch having at least two conductive states for selectively completing and interrupting a common electrical current carrying path to the actuator coils; and a control circuit coupled to the coil enabling circuit, the control circuit controlling the conductive state of the switch to disable the actuator coils without operator intervention during operation of the vehicle. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A control system for a vehicle transmission of the type including an input shaft, an output shaft, a plurality of intermeshing gears, a plurality of clutches associated with the gears and a plurality of electrical coils energizable to selectively engage and disengage the clutches in predetermined combinations to establish gear ratios between the input shaft and the output shaft, the control system comprising:
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a neutral circuit coupled to the coils, the neutral circuit preventing energization of the coils to place the transmission in a neutral condition upon startup of the vehicle; and a control circuit coupled to the neutral circuit, the control circuit cooperating with the neutral circuit to selectively prevent energization of the coils after startup of the vehicle. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification