US-12618468-B2 - Electric clutch for work vehicle power shift transmission

Abstract

Disclosed is an electric clutch including a clutch pack having clutch members transmitting torque when engaged, an input mechanism, and an actuator assembly. The input mechanism including a pinion gear configured to receive rotational input from an electric machine and a cam gear meshing with the pinion gear to rotate about a reference axis. The actuator assembly including an actuator spring and a cam disc disposed about the reference axis and engaging the cam gear at a cam ramp such that changing a clock position of the cam gear about the reference axis imparts translation of the cam disc along the reference axis to move the actuator spring. The actuator assembly further includes an actuator piston moved by the actuator spring in response to the translation of the cam disc to engage the clutch members of the clutch pack.

Inventors

• Randall L. Long
• Zachariah E. Albert
• Stacy K. Worley

Assignees

• DEERE & COMPANY

Dates

Publication Date

20260505

Application Date

20241025

Claims (18)

1. 1 . An electric clutch comprising: a clutch pack having clutch members transmitting torque when engaged; an input mechanism including: a pinion gear configured to receive rotational input from an electric machine; and a cam gear meshing with the pinion gear to rotate about a reference axis, the cam gear having a cam follower; and an actuator assembly including: an actuator spring; a cam disc disposed about the reference axis and engaging the cam gear at a cam ramp such that changing a clock position of the cam gear about the reference axis imparts translation of the cam disc along the reference axis to move the actuator spring, wherein the cam disc defines the cam ramp which is engaged by the cam follower to effect translation of the cam disc along the reference axis; and an actuator piston moved by the actuator spring in response to the translation of the cam disc to engage the clutch members of the clutch pack.
2. 2 . The electric clutch of claim 1 , wherein the pinion gear drives the cam gear between a range of clock angles about the reference axis corresponding to a range of translational positions of the cam disc along the reference axis.
3. 3 . The electric clutch of claim 2 , wherein a first translational position of the cam disc, the actuator spring is sized and configured to position the actuator piston to engage the clutch members, and in a second translational position of the cam disc, the actuator spring is sized and configured such that it does not position the actuator piston to engage the clutch members.
4. 4 . The electric clutch of claim 2 , wherein the actuator spring is configured to bias the actuator piston toward the clutch pack.
5. 5 . The electric clutch of claim 1 , wherein the cam disc has an annular peripheral flange extending about the reference axis and having a toothed periphery that fixes a clock position of the cam disc; and wherein the cam ramp is a radially raised surface that tapers along the annular peripheral flange of the cam disc.
6. 6 . The electric clutch of claim 5 , wherein the cam gear is a ring gear formed by an annular body extending about the reference axis and having an inner circumference and an outer circumference, and the outer circumference having a plurality of teeth that mesh with the pinion gear and the inner circumference having the cam follower.
7. 7 . The electric clutch of claim 1 , wherein the cam disc defines clock limiters on opposite ends of the cam ramp that engage the cam follower to impede rotation about the reference axis.
8. 8 . The electric clutch of claim 1 , wherein the pinion gear is a worm gear and the cam gear is a ring gear having a toothed outer circumference that is meshed with the worm gear to change the clock position of the ring gear about the reference axis.
9. 9 . The electric clutch of claim 1 , wherein the actuator spring is disposed concentrically about the actuator piston, the cam disc is disposed concentrically about the actuator spring, and the cam gear is disposed concentrically about the cam disc.
10. 10 . The electric clutch of claim 1 , wherein the actuator assembly further includes a return spring sized and configured to provide a return spring force that biases the actuator piston away from the clutch pack; and wherein the actuator spring is sized and configured to provide an actuating spring force that overcomes the return spring force in at least one translational position of the cam disc to translate the actuator piston toward the clutch pack.
11. 11 . The electric clutch of claim 1 , wherein the input mechanism includes the electric machine driving the pinion gear.
12. 12 . A transmission for a work vehicle, the transmission comprising: an output shaft; a gear providing a gear ratio; an electric clutch coupling the gear to the output shaft when engaged, the electric clutch comprising: a clutch pack having clutch members transmitting torque when engaged; an input mechanism including: a pinion gear configured to receive rotational input from an electric machine; and a cam gear meshing with the pinion gear to rotate about a reference axis, the cam gear having a cam follower; and an actuator assembly including: an actuator spring; a cam disc disposed about the reference axis and engaging the cam gear at a cam ramp such that changing a clock position of the cam gear about the reference axis imparts translation of the cam disc along the reference axis to move the actuator spring, wherein the cam disc defines the cam ramp which is engaged by the cam follower to effect translation of the cam disc along the reference axis; and an actuator piston moved by the actuator spring in response to the translation of the cam disc to engage the clutch members of the clutch pack.
13. 13 . The transmission of claim 12 , wherein the input mechanism includes the electric machine driving the pinion gear.
14. 14 . The transmission of claim 12 , wherein the pinion gear drives the cam gear between a range of clock angles about the reference axis corresponding to a range of translational positions of the cam disc along the reference axis.
15. 15 . The transmission of claim 12 , wherein a first translational position of the cam disc, the actuator spring is sized and configured to position the actuator piston to engage the clutch members, and in a second translational position of the cam disc, the actuator spring is sized and configured such that it does not position the actuator piston to engage the clutch members.
16. 16 . The transmission of claim 12 , wherein the cam gear is a ring gear formed by an annular body extending about the reference axis and having an inner circumference and an outer circumference, and the outer circumference having a plurality of teeth that mesh with the pinion gear and the inner circumference having the cam follower; and wherein the cam disc has an annular peripheral flange extending about the reference axis and having a toothed periphery that fixes a clock position of the cam disc, the cam ramp is a radially raised surface that tapers along the annular peripheral flange of the cam disc, and the cam disc defines clock limiters on opposite ends of the cam ramp that engage the cam follower to impede rotation about the reference axis.
17. 17 . The transmission of claim 12 , wherein the actuator spring is disposed concentrically about the actuator piston, the cam disc is disposed concentrically about the actuator spring, and the cam gear is disposed concentrically about the cam disc.
18. 18 . The transmission of claim 12 , wherein the actuator assembly further includes a return spring sized and configured to provide a return spring force that biases the actuator piston away from the clutch pack; and wherein the actuator spring is sized and configured to provide an actuating spring force that overcomes the return spring force in at least one translational position of the cam disc to translate the actuator piston toward the clutch pack.

Description

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not applicable. FIELD OF THE DISCLOSURE This disclosure generally relates to an electric clutch for a transmission system of a work vehicle. BACKGROUND OF THE DISCLOSURE Heavy-duty work vehicles, such as those used in the agricultural, construction, forestry, and mining industries, may be an electric vehicle using an electric machine to drive the work vehicle. The drive system of these heavy-duty work vehicles can benefit from power shifting where the clutch is slowly engaged and slightly slips before full engagement to allow shifting to occur smoothly. Pneumatic clutches run by hydraulics can perform the power shifting smoothly where two clutches carry torque for a portion of time between the shifting; however, these clutches require a hydraulic pump and hydraulic fluid to operate. Electric clutches work well when you can stop and shift or do a 100 percent synchronous shift, but electric clutches fall short when performing a power shift due to their design being more of an on/off clutch system. SUMMARY OF THE DISCLOSURE An electric clutch includes a clutch pack having clutch members transmitting torque when engaged, an input mechanism, and an actuator assembly. The input mechanism includes a pinion gear configured to receive rotational input from an electric machine and a cam gear meshing with the pinion gear to rotate about a reference axis. The actuator assembly includes an actuator spring, a cam disc, and actuator piston. The cam disc is disposed about the reference axis and engages the cam gear at a cam ramp such that changing a clock position of the cam gear about the reference axis imparts translation of the cam disc along the reference axis to move the actuator spring. The actuator piston is moved by the actuator spring in response to the translation of the cam disc to engage the clutch members of the clutch pack. In an example of the electric clutch, the pinion gear drives the cam gear between a range of clock angles about the reference axis corresponding to a range of translational positions of the cam disc along the reference axis. In a further example of the electric clutch, in a first translational position of the cam disc, the actuator spring is sized and configured to position the actuator piston to engage the clutch members, and in a second translational position of the cam disc, the actuator spring is sized and configured such that it does not position the actuator piston to engage the clutch members. In a further example of the electric clutch, the actuator spring is configured to bias the actuator piston toward the clutch pack. In a further example of the electric clutch, the cam disc defines the cam ramp and the cam gear has a cam follower that engages the cam ramp to effect translation of the cam disc along the reference axis. In a further example of the electric clutch, the cam disc has an annular peripheral flange extending about the reference axis and having a toothed periphery that fixes a clock position of the cam disc, and the cam ramp is a radially raised surface that tapers along the annular peripheral flange of the cam disc. In a further example of the electric clutch, the cam gear is a ring gear formed by an annular body extending about the reference axis and having an inner circumference and an outer circumference, and the outer circumference having a plurality of teeth that mesh with the pinion gear and the inner circumference having the cam follower. In a further example of the electric clutch, the cam disc defines clock limiters on opposite ends of the cam ramp that engage the cam follower to impede rotation about the reference axis. In a further example of the electric clutch, the pinion gear is a worm gear and the cam gear is a ring gear having a toothed outer circumference that meshes with the worm gear to change the clock position of the ring gear about the reference axis. In a further example of the electric clutch, the actuator spring is disposed concentrically about the actuator piston, the cam disc is disposed concentrically about the actuator spring, and the cam gear is disposed concentrically about the cam disc. In a further example of the electric clutch, the actuator assembly further includes a return spring sized and configured to provide a return spring force that biases the actuator piston away from the clutch pack, and wherein the actuator spring is sized and configured to provide an actuating spring force that overcomes the return spring force in at least one translational position of the cam disc to translate the actuator piston toward the clutch pack. In a further example of the electric clutch, the input mechanism includes the electric machine driving the pinion gear. A transmission for a work vehicle includes an output shaft, a gear providing a gear ratio, and an electric clutch coupling the gear to the output shaft when engaged. The electric clutch includes a clutch pack having clutch members tr