Double helix actuator with magnetic sections having alternating polarities

Patent metadata

Field	Value
Publication number	US-2023006528-A1
Application number	US-202217676073-A
Country	US
Kind code	A1
Filing date	Feb 18, 2022
Priority date	May 21, 2018
Publication date	Jan 5, 2023
Grant date	—

Abstract

A double helix actuator is disclosed that includes a double helix coil wound around a movable proof mass that is enclosed within a magnetic structure. The double helix coil and the magnetic structure are arranged relative to each other so that the magnetic field generated by the entirety of the double helix coil contributes to a linear force direction of the actuator. The double helix actuator produces a greater linear force density compared to traditional racetrack coil actuators, where only a portion of the coil contributes to the linear force. The double helix actuator also produces torque in addition to linear force which allows the double helix to provide unique haptic sensations in a variety of applications.

First claim

What is claimed is:

1 . A cylindrical double helix actuator, comprising:
a cylindrical housing; flexure caps attached to opposite ends of the cylindrical housing forming a cavity, each flexure cap have a flexure; a helically magnetized core disposed within the cavity between the flexures of the flexure caps; and a flex coil helically-wound around the helically magnetized core in accordance with a winding pattern that is an alternating solenoid with alternating dipole polarization and continuous helical polarization.

2 . The cylindrical double helix actuator of claim 1 , wherein the flex coil is configured as a periodic winding pattern on a rolled flex printed circuit board (PCB).

3 . The cylindrical double helix actuator of claim 2 , wherein the winding pattern reverses direction every other period to eliminate torque and has a varying period length to linearize force.

4 . The cylindrical double helix actuator of claim 1 , wherein the helically magnetized core is a progressively magnetized AlNiCo cylindrical core.

5 - 11 . (canceled)

12 . The cylindrical double helix actuator electronic device of claim 1 , wherein the flexure caps are rotated by about 90 degrees relative to each other.

13 . The cylindrical double helix actuator of claim 1 , wherein the flexure caps are attached to the helically magnetized core.

14 . The cylindrical double helix actuator of claim 1 , wherein the winding pattern direction is reversed so that a spring compression torque provided by the flexures is opposite a magnetic torque provided by the helically magnetized core.

15 . The cylindrical double helix actuator of claim 14 , wherein the spring compression torque is equal to the magnetic torque.

16 . An electronic device, comprising:
a haptic engine comprising:
a cylindrical, double helix actuator comprising:
a cylindrical housing;
flexure caps attached to opposite ends of the cylindrical housing forming a cavity, each flexure cap having a flexure;
a helically magnetized core disposed within the cavity between the flexures of the flexure caps; and
a flex coil helically-wound around the helically magnetized core in accordance with a winding pattern that is an alternating solenoid with alternating dipole polarization and continuous helical polarization;

a controller coupled to the haptic engine, the controller generating and sending a drive signal to the haptic engine to drive the haptic engine into motion, the drive signal being adjusted by the controller based on one or more feedback signals from the haptic engine that are generated in response to the motion; one or more processors; memory storing instructions that when executed by the one or more processors, cause the one or more processors to perform one or more operations comprising; and sending, to the controller, a request to generate a haptic sensation.

17 . The electronic device of claim 16 , wherein the flex coil is configured as a periodic winding pattern on a rolled flex printed circuit board (PCB).

18 . The electronic device of claim 17 , wherein the winding pattern is a 4-period winding pattern.

19 . The electronic device of claim 17 , wherein the winding pattern reverses direction every other period to eliminate torque.

20 . The electronic device of claim 17 , wherein the winding pattern has a varying period length to linearize force.

21 . The electronic device of claim 16 , wherein the helically magnetized core is a progressively magnetized AlNiCo cylindrical core.

22 . The electronic device of claim 16 , wherein the feedback signals include a back-electromotive force (EMF) voltage signal generated in response to the motion.

23 . The electronic device of claim 16 , wherein the feedback signals include voltage signals generated by one or more magnetic sensors in response to the motion.

24 . The electronic device of claim 16 , wherein the flexure caps are rotated by about 90 degrees relative to each other.

25 . The electronic device of claim 16 , wherein the flexure caps are attached to the helically magnetized core.

26 . The electronic device of claim 16 , wherein the winding pattern direction is reversed so that a spring compression torque provided by the flexures is opposite a magnetic torque provided by the helically magnetized core.

27 . The electronic device of claim 26 , wherein the spring compression torque is equal to the magnetic torque.

Assignees

• Apple Inc

Inventors

• Harrison Jere C
• Speltz Alex J
• Wu Xin Alice

Classifications

• H02K35/04

  with moving coil systems and stationary magnets · CPC title

• H02K2201/18

  Machines moving with multiple degrees of freedom · CPC title

• H02K41/03 Primary

  Synchronous motors; Motors moving step by step; Reluctance motors (H02K41/035 takes precedence) · CPC title

• H02K33/00

  Motors with reciprocating, oscillating or vibrating magnet, armature or coil system (arrangements for handling mechanical energy structurally associated with motors H02K7/00, e.g. H02K7/06) · CPC title