Device for detecting the angle of rotation

• US 5,657,544 A
• Filed: 09/26/1995
• Issued: 08/19/1997
• Est. Priority Date: 09/26/1995
• Status: Expired due to Term

• Current Assignee: Komatsu Ltd., NTN Corporation
• Original Assignee: Komatsu Ltd., NTN Corporation
• Inventors: Murakami, Taku, Kitsunai, Masami, Ota, Michio, Maruyama, Kizashi
• Primary Examiner(s): Bennett, G. Bradley
• Application Number:
  US08/533,855
• Time in Patent Office: 693 Days
• Field of Search: 33/1 L, 33/1 N, 33/1 PT, 33/706, 33/707, 33/534, 338/31, 338/32 K, 338/32 H
• US Class Current: 33/1.00N
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01D 5/165 by relative movement of a point of contact or actuation and a resistive track

Abstract

A rotational angle detecting device includes a rotary shaft 1 having an annular projection 1c formed therein so as to extend radially outwardly therefrom, and a housing 2 rotatably supporting the rotary shaft 1. A plurality of rolling contact bearings 6 each having inner and outer races are mounted on the rotary shaft 1 under a pre-loaded condition so as to sandwich the annular projection 1 c between the respective inner races of the rolling contact bearings 6. The assembly is rotatably received inside the housing 2 to permit the rotary shaft 1 to be rotatable about a longitudinal axis thereof. A resistor element 12 is disposed on an inner surface of a housing lid 3 in concentric relation to the longitudinal axis of the rotary shaft 1. An electroconductive brush 5 is secured to an end face of the rotary shaft 1 for rotation together with the rotary shaft 1 and held in sliding contact with the resistor element 12.

Claims

1. A rotational angle detecting device which comprises:

a rotary shaft having an annular projection formed therein so as to extend radially outwardly therefrom;

a housing rotatably supporting the rotary shaft;

a plurality of rolling contact bearings mounted on the rotary shaft and spaced from each other along a longitudinal axis of the rotary shaft, each of said rolling contact bearings having inner and outer races, said annular projection of the rotary shaft being sandwiched between the respective inner races of the neighboring rolling contact bearings in a pre-loaded condition, said plurality of the rolling contact bearings on said rotary shaft being received inside the housing to permit the rotary shaft to be rotatable about the longitudinal axis thereof; and

a rotational angle detecting means interposed between one end face of the rotary shaft inside the housing and a portion of a wall of the housing confronting said end face of the rotary shaft for detecting an angle of rotation of the rotary shaft relative to the housing.

2. The rotational angle detecting device as claimed in claim 1, wherein said rotational angle detecting means comprises an electroconductive brush secured to the rotary shaft and a resistor element disposed on said portion of the wall of the housing, said electroconductive brush being slidingly engaged with the resistor element.

3. The rotational angle detecting device as claimed in claim 1, wherein said rotational angle detecting means comprises a magnetic pattern formed on the rotary shaft in concentric relation with the longitudinal axis of the rotary shaft, and a detective element cooperative with the magnetic pattern and secured to said portion of the wall of the housing in alignment with the magnetic pattern.

4. A rotational angle detecting device which comprises:

a rotary shaft having an annular projection formed therein so as to extend radially outwardly therefrom;

a housing rotatably supporting the rotary shaft;

a plurality of rolling contact bearings mounted on the rotary shaft and spaced from each other along a longitudinal axis of the rotary shaft, each of said rolling contact bearings having inner and outer races, said annular projection of the rotary shaft being sandwiched between the respective inner races of the neighboring rolling contact bearings in a pre-loaded condition, said plurality of the rolling contact bearings on said rotary shaft being received inside the housing to permit the rotary shaft to be rotatable about the longitudinal axis thereof; and

a rotational angle detecting means for detecting an angle of rotation of the rotary shaft relative to the housing which comprises a first sensor including an electroconductive brush secured to the rotary shaft inside the housing, and a resistor element slidingly engageable with the electroconductive brush and disposed on a portion of a wall of the housing confronting an end face of the rotary shaft, and a second sensor including a magnetic pattern, formed on an end portion of the rotary shaft in concentric relation with the longitudinal axis of the rotary shaft, and a detective element cooperative with the magnetic pattern and secured to the housing in alignment with the magnetic pattern.

5. A rotational angle detecting device which comprises:

a rotary shaft having an annular projection formed therein so as to extend radially outwardly therefrom;

a housing rotatably supporting the rotary shaft;

a plurality of rolling contact bearings mounted on the rotary shaft and spaced from each other along a longitudinal axis of the rotary shaft, each of said rolling contact bearings having inner and outer races, said annular projection of the rotary shaft being sandwiched between the respective inner races of the neighboring rolling contact bearings in a pre-loaded condition, said plurality of the rolling contact bearings on said rotary shaft being received inside the housing to permit the rotary shaft to be rotatable about the longitudinal axis thereof;

a magnetic pattern formed on an outer peripheral face of the annular projection; and

a detective element disposed at a portion of a wall of the housing confronting the magnetic pattern, said detective element being cooperable with said magnetic pattern to detect an angle of rotation of the rotary shaft relative to the housing.

6. The rotational angle detecting device as claimed in claim 5, further comprising an electroconductive brush secured to the rotary shaft inside the housing, and a resistor element disposed on a portion of the wall of the housing which confronts an end face of the rotary shaft, said electroconductive brush being slidingly engaged with the resistor element.