CN110662335B - Structure for balancing nonuniformity of electromagnetic field at end part of speed selector - Google Patents

Abstract

The invention relates to a structure for balancing the non-uniformity of the electromagnetic field at the end of a speed selector, which comprises a collimating tube head, a collimating tube, a transition rod, an upper shell layer, a lower shell layer, an electromagnetic shielding layer, and an insulating layer; The length and width of the overall structure are not more than 40 mm, the diameter of the central measuring hole channel is 5 mm, and there are multiple installation through holes; It is pressed with screws between the electromagnetic shielding layer and the insulating layer. The connection of the structure is simple and reliable, and the coaxiality is good, which can reduce the electromagnetic field coupling error of the speed selector and improve the measurement accuracy.

Description

A structure for balancing the non-uniformity of the electromagnetic field at the end of the speed selector

technical field

The invention belongs to the field of electric propulsion plasma measurement, and relates to a structure for balancing the non-uniformity of the electromagnetic field at the end of a speed selector.

Background technique

Electric propulsion is a kind of propulsion method that uses electric energy to ionize and accelerate propellant to obtain thrust. At present, it has good application prospects in spacecraft orbit control, deep space exploration and interstellar navigation. In electric thrusters, however, there are many types of thrusters where the ion velocity in the plasma plume can be diagnosed by a velocity selector (a type of EXB probe).

A key part of the velocity selector for diagnosing ion velocity is the electromagnetic field region where there is a mismatch in the electromagnetic field decay gradients at the inlet and outlet, that is, coupling errors. This coupling error causes the ions to be deflected as they pass through the entrance region of the electromagnetic field, resulting in large systematic errors in the measurement results.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to design a structure for balancing the coupling error of the electromagnetic field of the speed selector, and to satisfy the shaftless rotation of the central hole channel through the cooperation of a mechanical structure.

The object of the present invention can be achieved by the following technical solutions: a structure for balancing the non-uniformity of the electromagnetic field at the end of the speed selector, comprising a collimating tube head, a collimating tube, a transition rod, an upper shell layer, a lower shell layer, Electromagnetic shielding layer and insulating layer; the length and width of the overall structure are not more than 40 mm, the diameter of the central measuring hole channel is 5 mm, and multiple installation through holes are provided; the transition rod and the shell are matched with an arc surface, and the transition rod is aligned with The pipe is connected by screw thread, and the shell and the electromagnetic shielding layer and the insulating layer are pressed by screws.

Further, the transition rod and the housing are matched by the arc surface, and can be rotated in an angle range of 24 degrees, which will not bring systematic errors to the ion collimation.

Further, the depth of the groove between the upper layer of the shell and the lower layer of the shell is greater than the height of the transition rod.

Further, the transition rod and the collimating tube are connected by a detachable thread.

Further, the shaftless rotating structure is adopted to solve the problem of the non-uniformity of the electromagnetic field at the end of the speed selector.

The advantages of the present invention are:

1. The structure design realizes the shaftless rotation of the central channel by means of surface coordination, which solves the problem of the non-uniformity of the electromagnetic field at the end of the speed selector.

2. Through the upper and lower fastening of the shell, the position accuracy and machining accuracy can be controlled by mechanical connection, which is simple and reliable.

3. Through the clearance fit between the transition rod and the arc surface of the lower layer of the shell, it is ensured that the transition rod and the shell still have good coaxiality when they rotate relative to each other.

4. There are arc-shaped holes on the upper layer of the shell, which cooperate with the threaded holes on the transition rod so that the rotated position of the transition rod can be fixed in time by bolts.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Figures 1(a)-1(c) are assembly and axonometric views of a structure for balancing the non-uniformity of the electromagnetic field at the tip of the speed selector.

Figure 2 is a simulation diagram of the ion motion trajectory.

In the figure: 1. Upper layer of casing; 2. Transition rod; 3. Lower layer of casing; 4. Electromagnetic shielding layer; 5. Insulation layer; 6. Collimating tube (one section); 7. Collimating tube head.

Detailed ways

The technical solutions of the present invention will be described in detail below with reference to the embodiments.

As shown in Figures 1(a)-1(c), a structure for balancing the non-uniformity of the electromagnetic field at the end of the speed selector includes an upper shell 1, a transition rod 2, a lower shell 3, and an electromagnetic shielding layer 4 , Insulation layer 5, collimating tube (section) 6, collimating tube head 7. As shown in the cross-sectional view, the head of the collimating tube and the collimating tube and between the collimating tube and between the collimating tube and the transition rod are all connected by threaded connections, the connection is simple and reliable, and the coaxiality is good.

To maintain coaxial rotation between the transition rod and the shell, it is necessary to ensure high position accuracy, good coaxiality and low friction at the same time. Considering the difficulty of processing, the shell is divided into upper and lower shell design. The depth of the groove is greater than the height of the transition rod, which brings the following advantages: 1. The processing difficulty of the layered design is greatly reduced; Easy to install; 3. The depth of the groove between the upper and lower layers is greater than the height of the transition rod, which can ensure that the transition rod and the shell are not subjected to the pre-tightening force of the screw, and reduce the frictional force when the overall structure rotates. The shell and the transition rod are fitted with arc surfaces and arc grooves and arc bosses, which can be rotated within an angle range of 24 degrees. At any angle, it can ensure that the ions incident from the entrance are not deflected. It will not be blocked and will not introduce systematic errors to the ion collimation. At the same time, there is a circular arc hole design on the upper layer of the shell, which cooperates with the threaded hole on the transition rod to fix the rotation position at the end of the rotation.

The theoretical basis of the structural design of the present invention is that when the ions move in the instrument, the ions will be deflected due to the unequal change gradient of the electromagnetic field at the end. The front end is the collimating tube area, the middle is the electromagnetic field area, and the tail end is the collection area. There is a slender and uniform electromagnetic field area in the electromagnetic field area, and the attenuation gradient of the electromagnetic field at the end is different, which makes the ions deflect. Therefore, a rotating structure needs to be added between the collimator and the electromagnetic field area to ensure that the ions move along the axis in the electromagnetic field area. direction.

The above are only preferred specific embodiments of the present invention, and the protection scope of the present invention is subject to the protection scope of the claims.

Claims (4)

1. a structure for balancing the non-uniformity of the electromagnetic field at the end of the speed selector, it is characterized in that: comprising a collimating tube head, a collimating tube, a transition rod, a casing upper layer, a casing lower layer, an electromagnetic shielding layer, an insulating layer The length and width of the overall structure are not more than 40 mm, the diameter of the central measuring hole channel is 5 mm, and multiple installation through holes are arranged; The shell and the electromagnetic shielding layer and the insulating layer are pressed by screws, and the transition rod and the shell are matched by the arc surface, and the angle range of 24 degrees can be rotated, which will not bring systematic errors to the ion collimation. 2. A structure for balancing the non-uniformity of the electromagnetic field at the end of the speed selector according to claim 1, wherein the depth of the groove between the upper layer of the casing and the lower layer of the casing is greater than the height of the transition rod. 3 . The structure for balancing the non-uniformity of the electromagnetic field at the end of the speed selector according to claim 1 , wherein the transition rod and the collimating tube are connected by a detachable thread. 4 . 4. A structure for balancing the non-uniformity of the electromagnetic field at the end of the speed selector according to claim 1, wherein the shaftless rotating structure is adopted to solve the problem of the non-uniformity of the electromagnetic field at the end of the speed selector .

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