Rotary position sensor

• US 9,297,637 B2
• Filed: 02/12/2014
• Issued: 03/29/2016
• Est. Priority Date: 02/17/2009
• Status: Active Grant

• Current Assignee: CTS Corporation
• Original Assignee: CTS Corporation
• Inventors: Wolschlager, Kevin C., Newman, Robert L., Cook, Kim D.
• Primary Examiner(s): Aurora, Reena
• Application Number:
  US14/178,319
• Publication Number:
  US 20140152296A1
• Time in Patent Office: 776 Days
• Field of Search: 324/207.25
• US Class Current: 1/1
• CPC Class Codes: G01B 7/30 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01D 1/00 Measuring arrangements giving results other than momentary value of variable, of general application G01D3/00 takes precedence; in tariff metering apparatus G01D4/00; transducers not specially adapted for a specific variable G01D5/00
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01D 15/00 Component parts of recorders for measuring arrangements not specially adapted for a specific variable
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01D 5/14 influencing the magnitude of a current or voltage
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A sensor assembly for sensing a movable object which, in one embodiment, includes a housing defining an interior cavity. A rotor is retained in the cavity. The rotor defines a central bore and a magnet is mounted in an off-center pocket defined by the rotor. The rotor is coupled to the shaft of the movable object whose position is to be measured. A sensor is also retained in the cavity in a relationship at least partially overlying the magnet and adapted to sense at least the direction of the magnetic field generated by the magnet to generate an electrical signal indicative of the position of the movable object. In another embodiment, the rotor and sensor are mounted in separate interior housing cavities separated by an interior housing wall.

Claims

1. A sensor assembly for sensing the position of a movable object, comprising:

a housing defining an interior cavity;

a sensor located in the housing;

a rotor located and rotatable in the cavity, the rotor including a collar defining a bore and a rotational axis for the rotor and the collar being adapted to receive a shaft, the sensor being located in the housing in a horizontally spaced and off-axis relationship relative to the rotational axis of the rotor;

a magnet located in a cavity defined in the rotor, the magnet and the cavity being located on the rotor in a horizontally spaced and off-axis relationship relative to the collar and the rotational axis of the rotor and the magnet and the sensor being located in a vertically overlying and spaced relationship relative to each other; and

the magnet and the sensor being movable relative to each other and the sensor being adapted to sense the magnitude and direction of the magnetic field and generate an electrical signal in response to the magnetic field sensed by the sensor.

2. The sensor assembly of claim 1, further comprising a plate secured to the housing and covering the cavity, the plate defining an aperture in alignment with the collar on the rotor, the shaft extending through the aperture in the plate and into the bore in the rotor.

3. The sensor assembly of claim 1, wherein the cavity defined in the rotor for the magnet is made of a plastic material over-molded around the magnet.

4. The sensor assembly of claim 1, wherein the sensor is located in the interior cavity of the housing.

5. The sensor assembly of claim 1, wherein the interior cavity in the housing defines a first interior cavity, the housing defining a second interior cavity, the rotor being located in the first interior cavity of the housing and the sensor being located in the second interior cavity of the housing, the first and second interior cavities being located in the housing in a vertically overlying and spaced relationship.

6. The sensor assembly of claim 5, wherein a wall in the housing separates the first and second cavities and the magnet and the sensor in the housing, the wail extending in a direction generally normal to the rotational axis of the rotor.

7. A sensor assembly for sensing the position of a movable object, comprising:

a housing defining an interior cavity;

a sensor located in the housing;

a rotor located and rotatable in the cavity, the rotor defining a bore defining a rotational axis for the rotor and the bore being adapted to receive a shaft, the sensor being located in the housing in a horizontally spaced and off-axis relationship relative to the rotational axis of the rotor;

a magnet located on the rotor, the magnet being located on the rotor in a horizontally spaced and off-axis relationship relative to the rotational axis of the rotor and the magnet and the sensor being located in a vertically overlying and spaced relationship relative to each other;

the magnet and the sensor being movable relative to each other and the sensor being adapted to sense the magnitude and direction of the magnetic field and generate an electrical signal in response to the magnetic field sensed by the sensor;

the rotor including a housing for the magnet, the housing for the magnet being made of a plastic material over-molded around the magnet; and

the housing for the magnet defining at least one slot dividing the housing into first and second portions, the second portion being adapted to flex independently of the first portion in response to a change in temperature.

8. A sensor assembly for sensing the position of a movable object, comprising:

a housing defining an interior cavity;

a sensor located in the housing;

a rotor located and rotatable in the cavity, the rotor defining a rotational axis and a bore adapted to receive a shaft, the sensor being located in the housing in a horizontally spaced and off-axis relationship relative to the rotational axis of the rotor;

a the magnet located on the rotor, the magnet being located on the rotor in a horizontally spaced and off-axis relationship relative to the rotational axis of the rotor and the magnet and the sensor being located in a vertically overlying and spaced relationship relative to each other; and

the magnet and the sensor being movable relative to each other and the sensor being adapted to sense the magnitude and direction of the magnetic field and generate an electrical signal in response to the magnetic field sensed by the sensor; and

the magnet including at least a first straight side surface oriented in a relationship parallel to the rotational axis of the rotor and the magnet generating a magnetic field extending through and in a direction generally normal to the rotational axis of the rotor and the first straight side surface of the magnet irrespective of the position of the magnet.

9. The sensor assembly of claim 8, wherein the a collar on the rotor defines the bore of the rotor, the collar adapted to receive the shaft, the first straight side surface of the magnet being positioned opposite and facing the collar on the rotor and the magnet including a curved side surface opposite and spaced from the first straight side surface of the magnet.