Differential lock actuation and control
An actuator for a differential lock includes an actuator pin that is resiliently coupled to a lead screw to prevent excess force on the actuator pin under otherwise damaging conditions, such as a tooth-on-tooth state of the differential. The actuator may include sensors for sensing the position of a lead screw nut and sensors for sensing the position of the actuating pin to provide improved control by sensing multiple states of the actuator, including a state in which a tooth-on-tooth condition is present in the differential.
1. A differential lock actuating device comprising:
a housing;
a lead screw rotatably mounted within the housing;
a lead screw nut cooperating with the lead screw;
an actuating pin cooperating with the lead screw nut;
a resilient coupling between the lead screw nut and the actuating pin; and
an electronic control unit including a first lead screw nut sensor for sensing a first position of the lead screw nut and a first actuating pin sensor for sensing a first position of the actuating pin.
2. The device of claim 1 , further comprising an actuating pin body having a bore, the actuating pin extending from the actuating pin body wherein the lead screw extends thru the bore of the actuating pin body.
3. The device of claim 1 , further comprising a nut guide having opposed nut guide end walls, each nut guide end wall having a nut guide wall bore, the lead screw extending thru each of the nut guide wall bores.
4. The device of claim 1 , wherein the resilient coupling comprises a spring.
5. The device of claim 1 , further comprising:
an actuating pin body having a bore, the actuating pin extending from the actuating pin body wherein the lead screw extends thin the bore of the actuating pin body;
a nut guide having opposed nut guide end walls, each nut guide end wall having a nut guide wall bore, the lead screw extending thru each of the nut guide wall bores;
and wherein the resilient coupling comprises a spring positioned between one of the nut guide end walls and the actuating pin body.
6. The device of claim 5 , wherein the spring is positioned concentrically with the lead screw.
7. The device of claim 5 , wherein the resilient coupling further comprises an elastomeric element positioned between the lead screw nut and one of the nut guide end walls.
8. The device of claim 1 , further comprising a second lead screw nut sensor for sensing a second position of the lead screw nut and a second actuating pin sensor for sensing a second position of the actuating pin.
9. The device of claim 1 , wherein the electronic control unit includes a microcontroller for receiving information from the first lead screw nut sensor and the first actuating pin sensor and determines a tooth-on-tooth condition of the differential lock based on the received information.
10. A method of operating a differential lock actuating device, the differential lock actuating device comprising: a housing; a lead screw rotatably mounted within the housing;
a lead screw nut cooperating with the lead screw; an actuating pin cooperating with the lead screw nut; a resilient coupling between the lead screw nut and the actuating pin; and an electronic control unit including a first lead screw nut sensor for sensing, a first position of the lead screw nut and a first actuating pin sensor for sensing a first position of the actuating pin, the method comprising:
rotating the lead screw to cause the lead screw nut to move in a locking direction;
transmitting force from the lead screw nut to the actuating pin through the resilient coupling;
sensing the position of the lead screw nut;
sensing the position of the actuating pin; and
determining a state of the actuator based on the sensed positions of the lead screw nut and actuating pin.
11. The method of claim 10 , wherein the step of determining a state of the actuator comprises determining that the actuator has experienced a tooth-on-tooth condition of a differential.
12. The method of claim 10 , wherein the step of determining a state of the actuator comprises determining that the actuator is in a locked state corresponding to a locked condition of a differential.
13. The method of claim 10 , further comprising the step of determining a state of the actuator comprises determining that the actuator is in an unlocked state.
14. The method of claim 10 , further comprising the step of adjusting a motive force applied to the lead screw based on the determined state of the actuator.