Resolver and motor

Patent metadata

Field	Value
Publication number	US-2019033098-A1
Application number	US-201815995160-A
Country	US
Kind code	A1
Filing date	Jun 1, 2018
Priority date	Jul 31, 2017
Publication date	Jan 31, 2019
Grant date	—

Abstract

A resolver includes a resolver rotor fixed to a rotating shaft, and a resolver stator disposed around the resolver rotor. The resolver stator includes an annular stator core having a plurality of salient poles which protrudes radially inward and which is disposed at regular intervals in a circumferential direction. The resolver rotor has an outer peripheral surface defined by an outer radius Rm(φ) which is obtained by blending, with respect to a first function Gp(φ) where an air gap between the resolver rotor and the salient poles is proportional to a sine wave (sin φ) related to an angle φ of the resolver rotor, a second function Gip(φ) where the inverse of the air gap is proportional to the sine wave (sin φ), at a predetermined ratio α.

First claim

1 . A resolver comprising:
a resolver rotor fixed to a rotating shaft; and a resolver stator disposed around the resolver rotor, wherein: the resolver stator includes an annular stator core which has a plurality of salient poles protruding radially inward and which is disposed at regular intervals in a circumferential direction; and the resolver rotor has an outer peripheral surface defined by an outer radius obtained by blending, with respect to a first function where an air gap between the resolver rotor and the salient poles is proportional to a sine wave related to an angle of the resolver rotor, a second function where an inverse of the air gap is proportional to the sine wave, at a predetermined ratio.

2 . The resolver according to claim 1 , wherein the ratio is set greater than zero, and is set to a greater value as a modulation factor representing a variable amplitude of an output signal from the resolver with respect to an average value of the output signal becomes smaller.

3 . The resolver according to claim 1 , wherein the ratio is set to a value not less than 0.2 and not more than 1.0.

4 . The resolver according to claim 1 , wherein the outer radius is calculated according to an expression (A), based on the angle, a stator inner radius indicating a length from the center of rotation of the shaft to a radially inner end face of the salient poles, the ratio, and a maximum value and a minimum value of the air gap set in advance:

Rm


(
φ
)

=

Rs
-

{

α
×

Gip


(
φ
)

+

(

1
-
α

)

×

Gp


(
φ
)

}





Gp


(
φ
)

=

{

(

G



max

-

G



min

)


sin



φ

}

/
2

+

(

G



min

+

G



max

)

/
2





Gip


(
φ
)

=

1

[

{

1

G



min

-

1

G


Assignees

• Mabuchi Motor Co

Inventors

• Yamamoto Shigeru

Classifications

• G01D5/2448 Primary

  Correction of gain, threshold, offset or phase control · CPC title

• H02K11/225 Primary

  Detecting coils · CPC title

• G01D5/204

  by influencing the mutual induction between two or more coils (G01D5/22 takes precedence) · CPC title

• G01D2205/77

  Specific profiles · CPC title

• G01D5/24433

  by mechanical means · CPC title