Clutch control for locked power take off shaft during power take off clutch engagement
AssigneeCase Corporation
InventorSatish L. Kale
Life of this patent
Estimating the term…
Abstract
A power take off (PTO) clutch control system for an agricultural tractor is disclosed herein. The PTO clutch is a hydraulic clutch which is operated by a proportional valve capable of pressurizing the clutch with hydraulic fluid at a pressure related to the pulse width of a pulse width modulated (PWM) control signal applied to the valve. The PWM signal is produced by a controller which monitors the input shaft speed and the output shaft speed. A first control signal is applied to the valve when both the input and output shaft speeds are greater than zero. A second control signal is applied to the valve when the input shaft speed has decreased by a predetermined amount and the output shaft speed is substantially zero.
Claims20
In a vehicle having a power source for producing rotational motion, a power take-off (PTO) shaft for supplying rotational motion to at least one piece of equipment other than the vehicle, and a clutch including an input shaft coupled to the power source and an output shaft coupled to the PTO shaft, wherein the clutch transmits a maximum torque between the input and output shafts in response to a maximum clutch engagement pressure and transmits a selectable torque between the input and output shafts in response to a selected clutch engagement pressure less than the maximum clutch engagement pressure, a control system comprising:
- a first transducer disposed to generate an input signal representative of the rotational speed of the input shaft;
- a second transducer disposed to generate an output signal representative of the rotational speed of the output shaft;
- a clutch control configured to engage and disengage the clutch in response to first and second control signals;
- and
- a control circuit coupled to the clutch control, the first transducer and the second transducer, and being configured to:
- apply first control signals to the clutch control when both the input and output shaft speeds are greater than zero, the first control signals corresponding to a selectable clutch engagement pressure less than the maximum clutch engagement pressure, and
- apply second control signals to the clutch control when the input shaft speed has decreased by a predetermined amount and the output shaft speed is substantially equal to zero, the second control signals corresponding to the maximum clutch engagement pressure.
A tractor comprising:
- a power source configured to produce rotational motion;
- a power take-off (PTO) shaft for supplying rotational motion to at least one piece of equipment other than the tractor;
- a clutch including an input shaft coupled to the power source and an output shaft coupled to the PTO shaft, wherein the clutch transmits a maximum torque between the input and output shafts in response to a maximum clutch engagement pressure and transmits a selectable torque between the input and output shafts in response to a selected clutch engagement pressure less than the maximum clutch engagement pressure;
- a clutch control configured to engage and disengage the clutch in response to a control signal;
- a first transducer disposed to generate an input signal representative of the rotational speed of the input shaft;
- a second transducer disposed to generate an output signal representative of the rotational speed of the output shaft;
- and
- a control circuit coupled to the clutch control, the first transducer and the second transducer, and being configured to apply to the clutch control said control signal representative of the maximum engagement pressure when the input shaft speed has decreased by a predetermined amount and the output shaft speed is substantially zero.
A tractor comprising:
- power means for producing rotational motion;
- a power take-off (PTO) shaft for supplying rotational motion to at least one piece of equipment other than the tractor;
- a clutch including an input shaft coupled to the power means and an output shaft coupled to the PTO shaft, wherein the clutch transmits a maximum torque between the input and output shafts in response to a maximum clutch engagement pressure and transmits a selectable torque between the input and output shafts in response to a selected clutch engagement pressure less than the maximum clutch engagement pressure;
- clutch control means for engaging and disengaging the clutch in response to a control signal;
- first means for generating an input signal representative of the rotational speed of the input shaft;
- second means for generating an output signal representative of the rotational speed of the output shaft;
- and
- controller means for monitoring the first and second means for generating, applying the control signal to the clutch control means, the control signal representative of the maximum engagement pressure when the input shaft speed has decreased by a predetermined amount and the output shaft speed is substantially zero.
In a tractor including a power take-off (PTO) shaft for supplying rotational motion to at least one piece of equipment other than the tractor, and a clutch including an input shaft coupled to a power source and an output shaft coupled to the PTO shaft, wherein the clutch transmits a maximum torque between the input and output shafts in response to a maximum clutch engagement pressure and transmits a selectable torque between the input and output shafts in response to a selected clutch engagement pressure less than the maximum clutch engagement pressure, a method for controlling the clutch engagement pressure when the output shaft is prevented from moving, the method comprising the steps of:
- a) generating a first signal representative of the rotational speed of the input shaft,
- b) generating a second signal representative of the rotational speed of the output shaft,
- c) generating a control signal in response to the first signal and the second signal, wherein the control signal is representative of the maximum clutch engagement pressure when the input shaft speed has decreased by a predetermined amount and the output shaft speed is substantially zero,
- d) selectively engaging and disengaging the clutch in response to the control signal.
Dependencies are inferred from the claim text.