Combined hub temperature and wheel speed sensor system

• US 6,538,426 B1
• Filed: 08/30/2000
• Issued: 03/25/2003
• Est. Priority Date: 08/30/2000
• Status: Expired due to Fees

• Current Assignee: Wabash Technologies Incorporated (Sensata Technologies Holding Plc)
• Original Assignee: Wabash Technologies Incorporated (Sensata Technologies Holding Plc)
• Inventors: Folsom, Keith, Tomlinson, Bruce, Enrietto, John
• Primary Examiner(s): Patidar, Jay
• Application Number:
  US09/650,557
• Time in Patent Office: 937 Days
• Field of Search: 324/174, 324/207.12, 324/165, 324/166, 324/173, 324/207.15, 324/207.17, 324/207.2, 324/207.21, 324/207.25, 324/225, 384/448, 310/68.B, 310/68.C, 374/183, 374/184
• US Class Current: 324/174
• CPC Class Codes: F16C 19/525 related to temperature and heat, e.g. insulation
• CPC Class Codes: F16C 2326/02 Wheel hubs or castors
• CPC Class Codes: F16C 33/723 Shaft end sealing means, e.g. cup-shaped caps or covers
• CPC Class Codes: F16C 41/007 Encoders, e.g. parts with a plurality of alternating magnetic poles
• CPC Class Codes: G01D 21/02 Measuring two or more variables by means not covered by a single other subclass
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01K 13/08 in rotary movement
• CPC Class Codes: G01P 3/443 mounted in bearings bearings F16C
• CPC Class Codes: G01P 3/487 delivered by rotating magnets

Abstract

A combined hub temperature and wheel speed sensor system comprises a sensor assembly coupled to an axle and a wheel assembly fixedly coupled to the wheel, which in turn is free to rotate with respect to the axle. The wheel assembly includes a ring magnet. The sensor assembly includes a temperature sensor in proximity to the wheel bearing, Hall effect sensors positioned to detect the rotation of the ring magnet, and a circuit for generating and transmitting signals corresponding to the wheel rotation speed, rotation direction, and bearing temperature.

Claims

1. A system for detecting the angular speed of a wheel affixed to an axle by a bearing, the system comprising:

a hub unit mounted to the axle of the wheel and rotationally coupled to the wheel, the hub unit comprising a ring magnet positioned substantially in a plane of rotation of the wheel, the ring magnet having a plurality of north and south poles facing radially with respect to an axis of rotation of the wheel;

a sensor unit positioned inside said hub unit and rotationally coupled to said axle and operative;

to detect a temperature related to a temperature of the bearing;

to detect said plurality of north and south poles as the wheel rotates;

to produce a signal corresponding to an angular speed of the wheel; and

to produce a signal corresponding to said temperature;

a first temperature sub-circuit connected to the sensor unit;

a second temperature sub-circuit connected to the sensor unit;

wherein said signal corresponding to said temperature is carried on said first temperature sub-circuit if the wheel is rotating in a first direction, and said signal corresponding to said temperature is carried on said second temperature sub-circuit if the wheel is rotating in a second direction.

2. The system of claim 1, wherein said speed signal is carried on a supply voltage sub-circuit, and wherein said speed signal indicates said angular speed by drawing current from a voltage supply as a function of said angular speed.

3. The system of claim 1, wherein said signal corresponding to said temperature is approximately linearly responsive to a temperature of said bearing.

4. A system for detecting the angular speed of a wheel mounted to an axle by a bearing and for detecting a temperature related to the temperature of the bearing, the system comprising:

a hub unit approximately 6 inches in diameter, 4.5 inches deep, and having a wall thickness of about 0.125 inches, the hub unit being mounted to the axle and rotationally coupled to the wheel, the hub unit comprising a ring magnet positioned substantially in a plane of rotation of the wheel, the ring magnet having approximately 50 alternating north and south poles facing radially inward; and

a sensor unit positioned inside said sub unit and that rotates as a unit with the axle, the sensor comprising;

at least two Hall effect sensors positioned to detect said alternating north and south poles in quadrature as the wheel rotates;

a temperature sensing element positioned close enough to the bearing to be responsive to a temperature of the bearing;

a first sub-circuit;

a second sub-circuit; and

wherein said sensor unit is operative to produce a temperature signal substantially linearly responsive to a temperature of said bearing and to place said temperature signal on said first sub-circuit if the wheel is rotating in a first direction and to place said temperature signal on said second sub-circuit if the wheel is rotating in a second direction, and

said sensor unit is operative to indicate an angular speed of the wheel by drawing current from a voltage source as a function of said angular speed.

5. A system for detecting the angular velocity and temperature of a rotating member, the system comprising:

a temperature sensor in proximity to a rotational mounting of the rotating member and adapted to produce a temperature signal corresponding to a temperature of a portion of the rotating member;

a rotation-indicating element affixed to the rotating member;

at least one rotation-detecting element adapted to detect both an angular speed and a direction of rotation of said rotation-indicating element; and

a processing element in communication with said temperature sensor and said rotation-detecting element, said processing element comprising a logic element responsive to said at least one rotation-detecting element to produce a speed signal corresponding to an angular speed of said rotating member and a direction signal corresponding to a direction of rotation of said rotating member;

a first sub-circuit and a second sub-circuit;

a switch having said direction signal as an input, and responsive to said direction signal to switch said temperature signal between said first sub-circuit and said second sub-circuit, such that said temperature signal is carried on said first sub-circuit when th wheel is rotating in a first direction, and on said second sub-circuit when the wheel is rotating in a second direction.