Magnetic load sensor and electric brake system

Patent metadata

Field	Value
Publication number	US-9599523-B2
Application number	US-201414759237-A
Country	US
Kind code	B2
Filing date	Jan 7, 2014
Priority date	Jan 10, 2013
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

A magnetic load sensor is provided which is high in axial rigidity. The load sensor includes a pair of parallel plate coupled together by coupling pieces. The coupling pieces are inclined relative to the axial direction such that when an axial load is applied to the parallel plates, the parallel plates are displaced relative to each other in a direction perpendicular to the axial direction, due to deflection of the coupling pieces. A magnetic target is mounted to the parallel plate, and a magnetic sensor element is mounted to the parallel plate such that when the parallel plates are displaced relative to each other in the direction perpendicular to the axial direction, the magnetic target and the magnetic sensor element are displaced relative to each other in the direction perpendicular to the axial direction.

First claim

What is claimed is:

1. A magnetic load sensor comprising:
a magnetic target configured to generate a magnetic field;
a magnetic sensor element configured to detect a magnitude of the magnetic field generated by the magnetic target;
a pair of parallel plates spaced apart from each other in an axial direction and extending parallel to each other; and
a plurality of coupling pieces arranged between the parallel plates and coupling the parallel plates together, the coupling pieces being spaced apart from each other;
wherein all of the coupling pieces are inclined in an incline direction relative to the axial direction and are connected to each of the pair of parallel plates such that, when a load in the axial direction is applied to the parallel plates, the coupling pieces are deflected in such a manner that the parallel plates are displaced relative to each other in a direction perpendicular to the axial direction,
wherein each of the magnetic target and the magnetic sensor element is mounted to a respective one of the parallel plates such that when the parallel plates are displaced relative to each other in the direction perpendicular to the axial direction, the magnetic target and the magnetic sensor element are displaced relative to each other in the direction perpendicular to the axial direction.

2. The magnetic load sensor of claim 1 , wherein all of the coupling pieces are inclined in a circumferential direction such that when a load in the axial direction is applied to the parallel plates, the parallel plates are moved relative to each other in the circumferential direction with centers of the respective parallel plates kept stationary.

3. The magnetic load sensor of claim 2 , wherein the magnetic target has a first N-pole and a first S-pole which are magnetized in a direction perpendicular to the direction in which the magnetic target and the magnetic sensor element are displaced relative to each other when the parallel plates are moved relative to each other in the circumferential direction perpendicular to the axial direction, and which are arranged adjacent to each other in the circumferential direction in which the magnetic target and the magnetic sensor element are displaced relative to each other, and wherein the magnetic sensor element is disposed in a vicinity of a boundary between the adjacent first N-pole and first S-pole.

4. The magnetic load sensor of claim 3 , wherein the magnetic target comprises a first permanent magnet having the first N-pole and a second S-pole at first and second opposite ends of the first permanent magnet, respectively, and a second permanent magnet having the first S-pole and a second N-pole at first and second opposite ends of the second permanent magnets, respectively, and wherein the first and second permanent magnets are bonded together while being arranged upside down relative to each other such that first N-pole and the second S-pole are arranged adjacent to the first S-pole and the second N-pole, respectively.

5. The magnetic load sensor of claim 2 , wherein the magnetic target and the magnetic sensor element are provided, respectively, on respective opposed surfaces of the parallel plates that face each other, and are located at radially outer portions of the respective opposed surfaces.

6. An electric brake system comprising an electric motor, and a motion converter mechanism configured to convert a rotational motion of the electric motor to an axial movement of a friction pad, and configured to generate a braking force by pressing the friction pad against a brake disk,
wherein the magnetic load sensor of claim 1 is mounted at a portion which receives an axially rearward reaction force that acts on the friction pad when the friction pad is pressed against the brake disk.

7. The magnetic load sensor of claim 1 , wherein the coupling pieces are connected to each of the pair of parallel plates and equally spaced apart from each other such that, when a load in the axial direction is applied to the parallel plates, the coupling pieces are deflected in such a manner that the parallel plates are rotated relative to each other in a circumferential direction perpendicular to the axial direction.

8. A magnetic load sensor comprising:
a magnetic target configured to generate a magnetic field;
a magnetic sensor element configured to detect a magnitude of the magnetic field generated by the magnetic target;
a pair of parallel plates spaced apart from each other in an axial direction and extending parallel to each other; and
at least one coupling piece coupling the parallel plates together,
wherein the at least one coupling piece is inclined relative to the axial direction and the at least one coupling piece is connected to each of the pair of parallel plates such that, when a load in the axial direction is applied to the parallel plates, the at least one coupling piece is deflected in such a manner that the parallel plates are rotated relative to each other in a circumferential direction perpendicular to the axial direction,
wherein each of the magnetic target and the magnetic sensor element is mounted to a respective one of the parallel plates such that when the parallel plates are rotated relative to each other in said circumferential direction perpendicular to the axial direction, the magnetic target and the magnetic sensor element are displaced relative to each other in said circumferential direction perpendicular to the axial direction.

9. The magnetic load sensor of claim 8 , wherein the magnetic target has a first N-pole and a first S-pole which are magnetized in a direction perpendicular to the direction in which the magnetic target and the magnetic sensor element are displaced relative to each other when the parallel plates are displaced relative to each other in the circumferential direction perpendicular to the axial direction, and which are arranged adjacent to each other in the circumferential direction in which the magnetic target and the magnetic sensor element are displaced relative to each other, and wherein the magnetic sensor element is disposed in a vicinity of a boundary between the adjacent first N-pole and first S-pole.

10. The magnetic load sensor of claim 9 , wherein the magnetic target comprises a first permanent magnet having the first N-pole and a second S-pole at first and second opposite ends of the first permanent magnet, respectively, and a second permanent magnet having the first S-pole and a second N-pole at first and second opposite ends of the second permanent magnets, respectively, and wherein the first and second permanent magnets are bonded together while being arranged upside down relative to each other such that first N-pole and the second S-pole are arranged adjacent to the first S-pole and the second N-pole, respectively.

11. The magnetic load sensor of claim 8 , wherein the magnetic target and the magnetic sensor element are provided, respectively, on respective opposed surfaces of the parallel plates that face each other, and are located at radially outer portions of the respective opposed surfaces.

12. An electric brake system comprising an electric motor, and a motion converter mechanism configured to convert a rotational motion of the electric motor to an axial movement of a friction pad, and configured to generate a braking force by pressing the friction pad against a brake disk,
wherein the magnetic load sensor of claim 8 is mounted at a portion which receives an axially rearward reaction force that acts on the friction pad when the friction pad is pressed against the brake disk.

Assignees

• Ntn Toyo Bearing Co Ltd

Inventors

• Masuda Yui

Classifications

• F16D65/12

  Discs; Drums for disc brakes · CPC title

• G01L5/28

  for testing brakes · CPC title

• F16D2066/005

  Force, torque, stress or strain · CPC title

• G01L5/225

  to foot actuated controls, e.g. brake pedals · CPC title

• F16D55/225

  the braking members being brake pads · CPC title