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US 12,441,392 B2Granted
Electric actuator steering system for forklifts
AssigneeToyota Material Handling, Inc.
InventorsJoseph Major, Kevin Partridge
Life of this patent
Estimating the term…
Abstract
An electric actuator for a steering system is adapted to control an angle of steered wheels on a vehicle to adjust a direction of travel of the vehicle. The electric actuator includes a housing assembly, an electric motor, and an actuation unit. The housing assembly is arranged around the electric motor and the electric motor is coupled with the actuation unit and configured to cause an actuator rod of the actuation unit to move relative to the housing assembly.
Claims20
An electric actuator for a steering system, the electric actuator comprising
- a linear actuation unit that includes an actuator rod that extends along an axis between a first end and a second end of the actuator rod and a ball screw nut arranged circumferentially around the actuator rod,
- an electric motor coupled with the ball screw nut and configured to rotate the ball screw nut about the axis and cause the actuator rod to translate axially relative to the ball screw nut, and
- a housing assembly arranged around and coupled with the electric motor, the housing assembly includes a case arranged around and coupled with the electric motor and a plurality of bushings engaged with the actuator rod and coupled with the case to facilitate translation of the actuator rod relative to the case, the plurality of bushings includes a first bushing, and a second bushing,
- wherein the case has a body arranged around and coupled with the electric motor, a first discrete stop flange that extends axially away from the body to block the first end of the actuator rod from being pushed into the body in response to an external force being applied to the actuator rod, and a second discrete stop flange that extends axially away from the body to block the first end of the actuator rod from being pushed into the body in response to the external force being applied to the actuator rod and the second discrete stop flange is axially aligned with and circumferentially spaced apart from the first discrete stop flange.
1 more element
An electric actuator for a steering system, the electric actuator comprising
- a linear actuation unit that includes an actuator rod that extends along an axis and a ball screw nut arranged circumferentially around the actuator rod,
- an electric motor coupled with the ball screw nut, and
- a housing assembly that includes a case arranged around and coupled with the electric motor, a first bushing, and a second bushing,
- wherein the first bushing is arranged circumferentially around and engaged with the actuator rod, the second bushing is arranged circumferentially around and engaged with the actuator rod, the first bushing and the second bushing are coupled to the case,
- wherein the case is formed to define an annular channel that opens radially inward toward the ball screw nut, the case further includes a sensor located in the annular channel and configured to measure a rotational position of the ball screw nut, the sensor including a position target board coupled to the ball screw nut for rotation therewith and an arcuate sensor board coupled with the case and located axially spaced apart from and adjacent the position target board such that the arcuate sensor board overlaps the position target board when viewed axially along the axis.
2 more elements
A method comprising
- coupling a first bushing to a case,
- coupling a second bushing to the case to cause the second busing to be spaced apart axially from the first bushing relative to an axis,
- coupling a third bushing to the case,
- coupling a fourth bushing to the case to cause the third busing to be spaced apart axially from the fourth bushing relative to the axis,
- inserting an actuator rod into a ball screw nut,
- engaging the first bushing and the second bushing with the actuator rod so that the first bushing and the second bushing are arranged circumferentially around the actuator rod such that the second bushing is located axially between the first bushing and a first end of the ball screw nut, and
- engaging the third bushing and the fourth bushing with the actuator rod so that the third bushing and the fourth bushing are arranged circumferentially around the actuator rod such that the third bushing is located axially between the fourth bushing and a second end of the ball screw nut,
- locating a sensor in an annular channel that opens radially inward and formed in the case, the sensor including a position target board coupled to the ball screw nut for rotation therewith and an arcuate sensor board coupled with the case and located axially spaced apart from and adjacent the position target board such that the arcuate sensor board overlaps the position target board when viewed axially along the axis.
5 more elements
Dependencies are inferred from the claim text.