CN110662335B

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

Info

Publication number: CN110662335B
Application number: CN201910909679.9A
Authority: CN
Inventors: 汤海滨; 董杨洋; 章喆
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2019-09-25
Filing date: 2019-09-25
Publication date: 2020-08-14
Anticipated expiration: 2039-09-25
Also published as: CN110662335A

Abstract

The invention relates to a structure for balancing the nonuniformity of an electromagnetic field at the end part of a speed selector, which comprises a collimator head, a collimator, a transition rod, an upper shell layer, a lower shell layer, an electromagnetic shielding layer and an insulating layer, wherein the collimator head is connected with the upper shell layer; the length and width of the whole structure are not more than 40 mm, the diameter of a central measuring hole channel is 5 mm, and a plurality of mounting through holes are formed; the transition rod is matched with the shell through an arc surface, the transition rod is in threaded connection with the collimator, and the shell is tightly pressed with the electromagnetic shielding layer and the insulating layer through screws. The structure is simple and reliable in connection and good in coaxiality, electromagnetic field coupling errors of the speed selector can be reduced, and measuring accuracy is improved.

Description

Structure for balancing nonuniformity of electromagnetic field at end part of speed selector

Technical Field

The invention belongs to the field of measurement of electrically propelled plasmas, and relates to a structure for balancing nonuniformity of an electromagnetic field at the end part of a speed selector.

Background

Electric propulsion is a propulsion mode which obtains thrust by ionizing and accelerating a propellant by using electric energy, and has good application prospects in orbit control, deep space exploration and interstellar navigation of a spacecraft at present. In the electric thruster, the ion velocity in the plasma plume of many thrusters can be diagnosed by a velocity selector (one type of EXB probe).

The velocity selector diagnoses the critical part of the ion velocity and the electromagnetic field area has electromagnetic field attenuation gradient mismatch, namely coupling error, at the inlet and the outlet. Such coupling errors can cause ions to deflect as they pass through the entrance region of the electromagnetic field, resulting in large systematic errors in the measurement results.

Disclosure of Invention

The invention mainly aims to design a structure for balancing electromagnetic field coupling errors of a speed selector, and the shaftless rotation of a central hole channel is met through the matching of a mechanical structure.

The purpose of the invention can be realized by the following technical scheme: a structure for balancing the nonuniformity of an electromagnetic field at the end part of a speed selector comprises a collimator head, a collimator, 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 whole structure are not more than 40 mm, the diameter of a central measuring hole channel is 5 mm, and a plurality of mounting through holes are formed; the transition rod is matched with the shell through an arc surface, the transition rod is in threaded connection with the collimator, and the shell is tightly pressed with the electromagnetic shielding layer and the insulating layer through screws.

Furthermore, the transition rod is matched with the shell through the arc surface, the angle range of 24 degrees can be rotated, and system errors cannot be brought to ion collimation.

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

Furthermore, the transition rod is detachably connected with the collimator tube through threads.

Furthermore, a shaftless rotating structure is adopted, so that the problem of non-uniformity of an electromagnetic field at the end part of the speed selector is solved.

The invention has the advantages that:

1. the structural design realizes the shaftless rotation of the central channel in a curved surface matching mode, and solves the problem of non-uniformity of an electromagnetic field at the end part of the speed selector.

2. Through the mode of buckling from top to bottom of the shell, the position precision and the machining precision can be controlled through mechanical connection, and the method is simple and reliable.

3. Through transition pole and the mode of casing lower floor's circular arc surface clearance fit, still have better axiality when guaranteeing transition pole and casing relative rotation.

4. The upper layer of the shell is provided with an arc-shaped hole, and the upper layer of the shell is matched with a threaded hole in the transition rod to ensure that the position of the transition rod after rotation can be fixed in time through a bolt.

Drawings

The invention will be further described with reference to the accompanying drawings.

FIGS. 1(a) -1(c) are assembly and isometric views of a structure for balancing velocity selector end electromagnetic field non-uniformities.

Fig. 2 is a simulation diagram of ion motion trajectory.

In the figure: 1. the upper layer of the shell; 2. a transition rod; 3. a lower layer of the housing; 4. an electromagnetic shielding layer; 5. an insulating layer; 6. collimator (one segment); 7. a collimator head.

Detailed Description

The technical solution of the present invention will be described in detail with reference to examples.

As shown in fig. 1(a) -1(c), a structure for balancing the nonuniformity of electromagnetic field at the end of a speed selector comprises a shell upper layer 1, a transition rod 2, a shell lower layer 3, an electromagnetic shielding layer 4, an insulating layer 5, a collimator (section) 6 and a collimator head 7. As shown in the cross section, the head of the collimator is in threaded connection with the collimator and the collimator as well as the collimator and the transition rod, so that the connection is simple and reliable, and the coaxiality is good.

Will keep coaxial rotation between transition pole and the casing, need guarantee simultaneously that position accuracy is high, the axiality is good and frictional force is little, considers the degree of difficulty in the processing, falls into two-layer shell design about the casing, and the groove depth between the upper and lower layer is greater than the height of transition pole, and the benefit of from this bringing has: 1. the processing difficulty of the layered design is greatly reduced; 2. the layered design can be installed in a mode of firstly installing the lower layer of the shell, then installing the transition rod and finally installing the upper layer of the shell, and the installation is convenient; 3. the depth of the groove between the upper layer and the lower layer is larger than the height of the transition rod, so that the pretightening force of the screw between the transition rod and the shell is not borne, and the friction force of the integral structure during rotation is reduced. Adopt the cooperation of arc surface and arc groove and circular arc boss between casing and the transition pole, rotatable 24 degrees angle ranges can guarantee that the ion of inciting from the entry can not blockked under the circumstances that is not deflected in arbitrary angle, can not bring system error to the ion collimation nature. Meanwhile, the upper layer of the shell is provided with an arc hole which is matched with a threaded hole in the transition rod to fix the rotating position when the rotation is finished.

The theoretical basis of the structural design of the invention is that when ions move in the instrument, the gradient of the change of the electromagnetic field at the end parts is unequal, so that the ions are deflected due to unbalanced force, and the movement force diagram is shown in figure 2. The front end is a collimation area, the middle is an electromagnetic field area, and the tail end is a collection area. The electromagnetic field region has a slender uniform electromagnetic field region, and the attenuation gradients of the electromagnetic field at the end part are different, so that ions are deflected, and therefore a rotating structure is required to be added between the collimator tube and the electromagnetic field region, and the movement angle of the ions in the electromagnetic field region is ensured to be along the axial direction.

The above-mentioned embodiments are merely preferred embodiments of the present invention, and the scope of the present invention is defined by the appended claims.

Claims

1. A structure for balancing velocity selector tip electromagnetic field non-uniformities, characterized by: the device comprises a collimator head, a collimator, a transition rod, a shell upper layer, a shell lower layer, an electromagnetic shielding layer and an insulating layer; the length and width of the whole structure are not more than 40 mm, the diameter of a central measuring hole channel is 5 mm, and a plurality of mounting through holes are formed; transition pole and casing adopt the arc surface cooperation, and transition pole and collimator adopt threaded connection, adopt the screw to compress tightly between casing and electromagnetic shield layer and the insulating layer, through the arc surface cooperation between transition pole and the casing, the angular range of rotatable 24 degrees can not bring system error to the ion collimation nature.

2. The structure of claim 1 for balancing velocity selector end electromagnetic field non-uniformities, characterized in that: the depth of the groove between the upper layer of the shell and the lower layer of the shell is larger than the height of the transition rod.

3. The structure of claim 1 for balancing velocity selector end electromagnetic field non-uniformities, characterized in that: the transition rod is detachably connected with the collimator tube through threads.

4. The structure of claim 1 for balancing velocity selector end electromagnetic field non-uniformities, characterized in that: and a shaftless rotating structure is adopted, so that the problem of non-uniformity of an electromagnetic field at the end part of the speed selector is solved.