Gas rate gyro

• US 4,941,353 A
• Filed: 01/12/1989
• Issued: 07/17/1990
• Est. Priority Date: 03/01/1988
• Status: Expired due to Fees

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Fukatsu, Yoshiaki, Matsui, Kazuma, Nomura, Etsuji
• Primary Examiner(s): Chapman, John
• Application Number:
  US07/296,191
• Time in Patent Office: 551 Days
• Field of Search: 73/516 LM, 73/516 R, 73/517 R, 73/505
• US Class Current: 73/504.05
• CPC Class Codes: G01C 19/58 Turn-sensitive devices without moving masses
• CPC Class Codes: G01P 15/08 with conversion into electric or magnetic values

Abstract

A hermetic tubular casing hermetically containing a gas substantially at the atmospheric pressure is mounted on a mobile object, such as a vehicle, and is provided with a needle electrode at one end thereof and a pair of adjacent semicircular plate electrodes at the other end thereof. A high-voltage power supply applies a high voltage across the needle electrode and the plate electrodes to generate an ionic wind flowing from the needle electrode toward the plate electrodes by producing a corona discharge around the needle electrode. An arithmetic unit detects the difference between ionic currents flowing respectively through the pair of plate electrodes and each corresponding to the number of ions fallen on the corresponding plate electrode. The ionic wind is deflected under the action of a Coriolis force as the mobile object revolves entailing variation in the quantity of ions falling on each plate electrode. The difference between the ionic currents varies in proportion to the angular velocity of the mobile object.

Claims

1. A gas rate gyro mounted on a mobile object to detect the rotatory motion of the mobile object through the measurement of the deflection of a gas flow varying as a function of the rotatory motion of the mobile object comprising:

a hermetic casing carried on the mobile object and hermetically containing a gas substantially of neutral molecules;

a first electrode comprising a needle electrode and disposed at one end of the hermetic casing;

a second electrode comprising a pair of grid electrodes disposed adjacently and electrically connected so the grid electrodes are at the same potential, and disposed within the casing at a predetermined distance from an opposite to the first electrode;

a high-voltage power supply which applies voltage across the first and second electrodes to produce a corona discharge around the first electrode so that an ionic wind composed of a mixture of the neutral molecules of the gas and ions produced by ionizing the neutral molecules flows from the first electrode toward the second electrode;

a detecting electrode comprising a pair of split electrodes for giving electrons to the ions contained in the ionic wind, disposed at a position within the casing at a predetermined distance from the first electrode where the ions produced by a corona discharge are not annihilated; and

a detecting circuit, connected to said pair of split electrodes, which detects the intensity of difference between the ionic currents flowing respectively through the split electrodes to detect a rotatory motion of the mobile object through the measurement of the deflection of the ionic wind resulting from the rotatory motion of the mobile object.

2. A gas rate gyro according to claim 1, wherein said second electrode is disposed between said first electrode and said detecting electrode.

3. A gas rate gyro according to claim 1, wherein the pressure of the gas within said casing is in the range of 710 to 810 mmHg.

4. A gas rate gyro according to claim 1, wherein said gas is nitrogen gas, dry air, an inert gas or a mixture of those gases.

5. A gas rate gyro according to claim 1, wherein the size of the meshes of said grid electrode is greater than 0.6D, where D is the diameter of said needle electrode, and said detecting electrode is disposed along an axis of said needle electrode within the 0.6D.

6. A gas rate gyro according to claim 1, wherein the predetermined dIstance between said first electrode and said detecting electrode is 30 mm or below.

7. A gas rate gyro according to claim 1, wherein said grid electrodes are interconnected electrically by grounded lead wires.

8. A gas rate gyro mounted on a mobile object to detect the rotatory motion of the mobile object through the measurement of the deflection of a gas flow varying as a function of the rotatory motion of the mobile object, comprising:

a hermetic casing carried on the mobile object and containing a gas having suitable pressure for corona discharge;

a first electrode disposed at one end of the casing to generate ions by the corona discharge having a potential core extending in alignment with an axis of the first electrode;

a second electrode comprising a pair of grid electrodes disposed adjacently and electrically connected so that the grid electrodes are at the same potential, and disposed within the casing at a predetermined distance from and opposite to the first electrode;

a high-voltage power supply which applies a voltage across the first and second electrodes to produce the corona discharge around the first electrode;

a detecting electrode for giving electrons to the ions contained in the potential core passing through said second electrode, disposed at a position within the casing at a predetermined distance from the first electrode where the ions produced by the corona discharge are not annihilated; and

a detecting circuit which detects the intensities of ionic currents flowing through the detecting electrode to detect a rotatory motion of the mobile object through the measurement of the deflection of the ionic wind resulting from the rotatory motion of the mobile object.