Integral rotational displacement sensor for an hydraulic motor

An apparatus for determining a variety of operating parameters, including incremental rotational movement, speed and torque, of a fluid motor having a rotor comprising:

• a deflectable region on the motor housing, the region deflecting in response to stress applied to the region in response to variations in pressure in a plurality of areas within the motor as the motor operates, sensing means for sensing the resulting strain on the region and producing a signal indicative of the occurrence and amount of the strain, and pressure coupling means including a plurality of apertures for selectively communicating variations in pressure from at least two of said areas at a time to vary the stress applied to the region to modify the signal to enable said sensing means to produce a signal defined by at least three states permitting at least incremental movement of the rotor to be determined from the signal.

A method for determining operating torque of a fluid motor having a rotor assembly including a rotor, comprising the steps of:

• sensing incremental changes in the rotation of the rotor relative to a reference position by generating a signal having a known number of state changes for a given angular rotation of the rotor, detecting each change in state of the signal until the known number of state changes has been detected, and averaging the amplitude of the signal over a time interval which elapses in detecting the known number of state changes.

A method for determining the operating speed of a fluid motor having a rotor assembly including a rotor comprising the steps of:

• sensing incremental changes in the rotation of the rotor relative to a reference position by generating a signal having a known number of state changes for a given angular rotation of the rotor, detecting each change in state of the signal until the known number of state changes has been detected, timing the interval of time which elapses in detecting the known number of state changes, and using the elapsed time to determine the speed of the motor.

Apparatus for determining an operating parameter of a fluid motor having a rotor assembly including a rotor and a rotor housing comprising pressure sensing means and pressure coupling means interposed between said rotor assembly and said pressure sensing means for communicating to said pressure sensing means variations in pressure produced within the motor in response to rotation of the rotor within the rotor housing, said pressure sensing means producing a pressure signal indicative of the pressure variation, and said pressure coupling means including a plurality of apertures for selectively coupling pressure variations to said pressure sensing means whereby the pressure signal produced by said pressure sensing means is defined by at least three states, permitting at least incremental movement of the rotor to be determined from the pressure signal, one of said apertures of said pressure coupling means cooperating with the rotor to define a reference position for the rotor, the pressure signal produced by said pressure sensing means indicating each time the rotor passes through the reference position.

An apparatus for determining an operating parameter of a fluid motor having a rotor comprising:

• a deflectable region on the motor housing, the region deflecting in response to stress applied to the region in response to variations in pressure produced in a plurality of areas from within the motor as the motor operates, sensing means for sensing the resulting strain on the region and producing a signal indicative of the occurrence and amount of the strain, and pressure coupling means including a plurality of apertures for selectively communicating variations in pressure from at least two of said areas at a time to vary stress applied to the region to modify the signal to enable said sensing means to produce a signal defined by at least three states permitting at least incremental movement of the rotor to be determined from the signal, said coupling means constructed and arranged to cooperate with the rotor to communicate to said sensor means a stress variation indicative of an absolute position of the rotor.

Apparatus for determining a variety of operating parameters, including incremental rotational movement, speed and torque, of a fluid operated device having a rotating assembly including a rotating member, comprising:

• pressure sensing means and pressure coupling means interposed between said rotating member and said pressure sensing means for communicating to said pressure sensing means variations in pressure produced in a plurality of areas withint he fluid operated device in response to rotation of the rotating member, said pressure sensing means producing a pressure signal indicative of the pressure variations, and said pressure coupling means including a plurality of apertures disposed for selectively coupling pressure variations from at least two of said areas at a time to said pressure sensing means, whereby the pressure signal produced by said pressure sensing means is defined by at least three states, permitting at least incremental movement of the rotating member to be determined from the pressure signal.