JPH0968154A - Arc jet propeller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always hold a space between an anode and a cathode to a distance improving an arc discharge, in an arc jet propeller used in attitude control or orbit control and the like of an artificial satellite or the like. SOLUTION: A device comprises a bellows 20 protruded to the outside of a propeller to seal the other end side of a cathode 6 in an opposite side to an opposed side to an anode 1, drive mechanism set up in the other end part of the cathode inserted to the bellows to be protruded to the outside and to drive the cathode in an axial direction and a control device 23 measuring voltage of the anode and the cathode opposed to this anode to output a drive signal driving the cathode in an axial direction to the drive mechanism so that the voltage comes to be voltage corresponding to a distance between the well arc discharging anode and cathode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention heats a propellant (gas) supplied between a cathode and an anode by arc discharge, and when the heated propellant gas is discharged from a propulsion device to the outside. The present invention relates to an arc jet propulsion machine used for an artificial satellite or the like, which obtains a propulsive force for performing attitude control, orbit control, or the like by the generated reaction force.

[0002]

2. Description of the Related Art FIG. 2 shows a vertical cross-sectional view of an arc jet propulsion machine conventionally used for artificial satellites and the like. In the figure, reference numeral 1 is an anode (anode) provided at the front end of the propulsion device 30. The supplied propellant gas is heated by an arc discharge generated between the propellant gas and a cathode 6 described later, and the heated propulsion is performed. A Laval nozzle that aerodynamically accelerates the agent gas and discharges the agent gas to the outside is formed in the axial center portion.

The reference numeral 2 designates a supply nozzle which is installed behind the anode 1 and which supplies the propellant gas to the arc discharge portion through holes radially formed from the outer peripheral portion thereof toward the axial center portion. The housings 4 constituting the outer shell of the first half of the above are housed in the housing 3, and a hole through which the cathode 6 penetrates is bored in the axial center part, and the propellant gas is provided between the housing 3 and the housing 3 on the outer peripheral surface. A cylindrical front insulator 5 having a supply path formed therein is connected to a rear end portion of the front insulator 4, and plungers 12, 13 for positioning the cathode 6 penetrating the inside of the shaft center portion, And these plungers 12, 13
The compartment housing the spring 14 for fixing is the rear insulator provided.

Reference numeral 6 is insulated from the anode 1 by a front insulator 4 and a rear insulator 5 which penetrate the inside.
The tip, which is the end side, is a cathode (cathode) that is arranged to face the anode 1 with a predetermined gap. 7
Is a cathode retainer that protrudes from the rear end of the rear insulator 5 to the outside of the propulsion unit 30 to seal the protrusion of the cathode 6, and 8, 9, 10 denote between the anode 1 and the supply nozzle 2.
Between the supply nozzle 2 and the front insulator 4, and the rear insulator 5
A gasket that is interposed between the cathode holding member 7 and the cathode holding member 7 to prevent the supplied propellant gas from leaking out of the propulsion unit 30.

Reference numeral 11 denotes a supply port that radially penetrates the rear insulator 5 from the outer peripheral portion to supply the propellant gas into the plunger 12, and 15 denotes a flange projecting from the outer peripheral surface of the rear end portion of the housing 3. A fixing screw for fixing and positioning the entire propulsion device 30 by connecting the flange fitted to the outer peripheral surface of the rear insulator 5 and fixing the housing 3 and the rear insulator 5.

The conventional arc jet propulsion machine is constructed in this way, and a propellant gas such as hydrazine decomposition gas is supplied to the supply port 11 from a tank provided in an artificial satellite or the like and the inside of the plunger 13 is supplied. , Plunger 1
2 through the groove provided between the outer peripheral surface of the rear insulator 5 and the outer peripheral surface of the rear insulator 5, and between the outer peripheral surface of the front insulator 4 and the inner peripheral surface of the housing 3, and the supply nozzle at the front end. 2 is fed to the anode 1 and the cathode 6 from the outer periphery of the supply nozzle 2 in the axial center portion.
Is supplied to the arc discharge part of. The propellant gas supplied to the arc discharge unit is connected to a power source (not shown) and heated by the arc discharge generated between the cathode 6 and the anode 1 for discharging.

Further, in the arc discharge part, as shown in the schematic view of FIG. 3, a Laval nozzle including a converging part 17, a constrictor 16 and an expanding part 18 is formed in the axial center part of the anode 1 as described above. The propellant gas heated in the arc discharge section is supplied to the converging section 17 and the constrictor 1.
6, while being aerodynamically accelerated while passing through the expansion section 18, the propulsion unit 3
It is released to the outside of 0. The attitude of an artificial satellite or the like equipped with an arc jet propulsion device is controlled by the force acting on the propulsion device 30 which receives the reaction force of the propellant gas released to the outside.

In such an arc jet propulsion machine, in order to maintain stable arc discharge between the anode 1 and the cathode 6, the distance between the constrictor 16 constituting the cathode 6 and the anode 1 shown in FIG. It is necessary to hold δ at an appropriate distance. However, long-term propulsion machine 3
With the operation of 0, the tip of the cathode 6 is worn and the distance δ changes. Therefore, in the conventional arc jet propulsion machine,
There is a problem that the arc discharge becomes unstable and the performance deteriorates.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the conventional arc jet propulsion machine, the present invention keeps the distance between the facing portion of the cathode and the anode at a distance that always maintains stable arc discharge. It is an object of the present invention to provide an arc jet propulsion device that can always maintain stable arc discharge and always generate a predetermined thrust as designed even when the tip of the cathode is worn.

[0010]

Therefore, the arc jet propulsion apparatus of the present invention has the following means.

(1) The cathode, which is arranged so as to face the anode, is covered with a projecting portion that projects from the propulsion unit on the other end side opposite to the one end side facing the anode, and is supplied into the propulsion unit. A bellows was installed to prevent the propellant gas from leaking outside.

(2) A drive mechanism for moving the cathode in the axial direction is provided on the other end side of the cathode that protrudes to the outside after passing through the bellows. The drive mechanism shall consist of a rack screwed in the axial direction of the cathode, a combination of a pinion that meshes with this rack and moves the cathode in the axial direction together with the rack by rotation, and a stepping motor that rotates the pinion. You can Alternatively, the cathode may be moved in the axial direction by utilizing pressure such as hydraulic pressure or air pressure.

(3) The distance between the anode and the cathode is detected by measuring the voltage between the anode and the cathode, each of which is connected to the power supply, from the relationship between the voltage and the distance that are associated in advance. In order to set the distance between the anode and the cathode to a predetermined length that enables stable plasma discharge, a drive signal for moving the cathode in the axial direction is sent to the drive mechanism. A control device for outputting is provided.

As described above, in the arc jet propulsion machine of the present invention, the cathode end portion on the side opposite to the anode side is guided to the outside of the arc jet propulsion machine through the bellows and projected to the outside of the cathode. By using a rack and pinion gear attached to the end and a driving device such as a stepping motor, the cathode installation position can be changed, and the voltage between the anode and the cathode can be detected and the cathode position can be corrected by this voltage. By installing a control device that outputs a drive signal to operate the drive device, the installation position of the cathode is adjusted appropriately according to the degree of wear of the cathode, and the distance between the anode and the cathode is stable arc discharge. Can always be maintained at a predetermined value that can be maintained. As a result, the arc jet propulsion machine can always perform good arc discharge, generate thrust required for attitude control, etc., and prevent performance deterioration of the arc jet propulsion machine.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an arc jet propulsion machine of the present invention will be described below with reference to the drawings. FIG.
FIG. 1 is a vertical sectional view showing a first embodiment of an arc jet propulsion machine of the present invention. It should be noted that the same components as those in the conventional example are denoted by the same reference numerals and the description thereof will be omitted.

In FIG. 1, reference numeral 20 denotes a bellows, which is movable in the direction of the arrow and is opposite to the side of the cathode 6 installed at the axial center of the front insulator 4 and the rear insulator 5 opposite to the anode 1. To prevent the propellant gas supplied to the inside of the propulsion device 30 from leaking to the outside. Reference numeral 21 is a stepping motor which constitutes a drive mechanism, and 22 is a rack and pinion gear which constitutes a drive mechanism together with the stepping motor 21 and which converts the rotational movement of the stepping motor 21 into a linear movement of the cathode in the arrow direction.

Reference numeral 23 denotes a control device, which is connected to a power source (not shown) and has detection terminals on the anode 1 and the cathode 6 which are loaded with a high voltage, respectively.
The voltage between the anode 1 and the cathode 6 that fluctuates in accordance with the separation distance between the anode 1 and the cathode 6 is measured, and this voltage and the arc discharge generated between the anode 1 and the cathode 6 which have been investigated in advance are stabilized. By comparing a predetermined voltage corresponding to a predetermined distance between the anode 1 and the cathode 6 maintained as above, a drive signal for setting the installation position of the cathode 06 to a predetermined distance from the anode 1 is output to the stepping motor.

As described above, in the arc jet propulsion machine of this embodiment, according to the voltage between the cathode 6 and the anode 1,
The stepping motor 21 rotates according to a drive signal sent from the control device 23 to the stepping motor 21 as a drive device, and the axial installation position of the cathode 6 can be arbitrarily set via the rack and pinion gear 22.
Therefore, the arc jet propulsion machine operates for a long time, the tip of the cathode 6 is worn, and the cathode 6 and the contactor 16 are damaged.
When the gap δ between the cathode 6 and the anode widens, the position of the cathode 6 can be set again to maintain an appropriate gap δ between the cathode 6 and the constrictor 16 and to stabilize the arc. A discharge can be generated and a stable propulsive force for control can be obtained.

In the above embodiment, the drive mechanism is the stepping motor 21 and the rack and pinion 22.
However, it is also possible to drive the cathode 6 in the axial direction by hydraulic pressure or pneumatic pressure.

[0020]

As described above, according to the arc jet propulsion machine of the present invention, the position of the cathode of the arc jet propulsion machine is calculated from the voltage difference between the anode and the cathode, by the structure shown in the claims. By the drive signal
Since it can be set arbitrarily, the gap between the cathode and anode constrictors can always be maintained properly during operation of the arc jet propulsion machine, especially when the cathode is worn due to long-term operation Can be maintained properly. As a result, stable arc discharge can be maintained at all times, so that an arc jet propulsion machine with less performance deterioration can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of an arc jet propulsion machine of the present invention,

FIG. 2 is a vertical sectional view showing an example of a conventional arc jet propulsion machine,

FIG. 3 is a schematic diagram showing a facing portion of an anode and a cathode of an arc jet propulsion machine.

[Explanation of symbols]

1 Anode 2 Supply Nozzle 3 Housing 4 Front Insulator 5 Rear Insulator 6 Cathode 7 Cathode Retainer 8, 9, 10 Gasket 11 Supply Port 12, 13 Plunger 14 Spring 15 Fixing Screw 16 Constrictor 17 Converging Part 18 Enlarging Part 20 Bellows 21 Stepping motor constituting drive unit 22 Rack and pinion constituting drive unit 23 Control unit 30 Propulsion unit

Claims (1)

[Claims] 1. The supplied propellant gas is heated by an arc discharge generated between an anode and a cathode arranged so that one end of the anode is opposed to the anode, and the propellant gas is discharged outward from a nozzle to generate thrust. In the arc jet propulsion device thus obtained, a bellows that seals the protruding portion on the other end side of the cathode that projects to the outside from the propulsion device and the other end side of the cathode that projects to the outside A drive mechanism that moves in the axial direction and a voltage between the anode and the cathode are detected, and the voltage becomes a predetermined value.
An arc jet propulsion machine comprising: a control device that outputs a drive signal for moving the cathode to the drive mechanism.