CN108762314A - A kind of vacuum sealing displacement mechanism for the small force measuring device of super-conductive magnetic suspension - Google Patents

Abstract

The invention discloses a manual height-adjustable vacuum-sealed displacement mechanism for superconducting magnetic levitation. The mechanism is integrally installed on the outer bottom surface of a vacuum chamber, including an upper flange, a guide rail, a lower flange, a slider, a support rod, and a lead screw. Vice, positioning ring, hand wheel, sealing device and measuring device; the upper flange, guide rail and lower flange are fixedly connected together, the slider passes through the guide rail, and is placed between the upper flange and the lower flange, and can be moved along the guide rail Slide up and down; the upper end of the slider is welded to the support rod, the upper end of the support rod passes through the bottom plate of the vacuum cabin to support the structure in the cabin, the lower end of the slider is connected to the screw nut; the bellows is sleeved around the support rod, and the upper end is welded on the upper flange. The lower end is welded on the slider to play a sealing role. When the hand wheel fixed on the lead screw is shaken, since the lead screw is fixed in the axial direction, the slider connected to the lead screw nut will move up and down with the nut, and at the same time drive the support rod to move up and down, thereby adjusting Highly effective. The upper and lower measuring jaws of the measuring device are respectively fixed on the upper flange and the slider. When the slider moves, the amount of change in the indication of the measuring device is the displacement change of the slider.

Description

A Vacuum Sealed Displacement Mechanism for Superconducting Magnetic Suspension Microforce Measuring Device

technical field

The invention relates to a vacuum sealing displacement mechanism, in particular to a manually adjustable vacuum sealing displacement mechanism used for a superconducting magnetic levitation micro force measuring device.

Background technique

The high-temperature superconducting magnetic ^levitation micro-force measuring device is a self-stabilizing, low-loss, high-load, and high-precision micro-thrust measuring device. Thrust test requirements. The high-temperature superconducting magnetic levitation micro-force measurement device usually includes a vacuum chamber, a high-speed camera, a permanent magnet platform, a superconductor platform, a low-temperature system, and a floating mechanism. Cryogenic cooling of the superconductor platform.

When the superconducting platform is at room temperature, the permanent magnet platform is not subject to levitation force, and at this time, the permanent magnet platform is adjusted to a specified height by a displacement mechanism and is coaxial with the superconducting platform. Then close the door of the vacuum chamber and start vacuuming. After the vacuum degree reaches the working requirements, the cryogenic system starts to refrigerate, so that the superconductor platform enters a superconducting state. At this time, adjust the displacement mechanism again to make the permanent magnet platform drop and stably suspend above the superconductor platform. . In order to achieve accurate and stable suspension, the initial position of the permanent magnet platform must be strictly controlled, which requires that the control of the displacement mechanism must be accurate and reliable.

A common solution is an electric drive method, in which the horizontal support plate is driven by a horizontal stepping motor and a vertical stepping motor, thereby adjusting the horizontal position and height of the permanent magnet platform. Although this displacement mechanism can meet the basic control requirements, it still has the following problems:

First, the displacement mechanism has a large volume and complicated wiring, which occupies a large amount of space in the cabin and affects the installation of other experimental devices in the cabin; second, the displacement mechanism uses a large amount of metal and is far away from the superconductor platform and the permanent magnet platform. Recently, these metals will interfere with the magnetic field of the platform and generate large eddy current loss, which will adversely affect the high-precision levitation measurement. Therefore, it is necessary to provide a displacement mechanism with compact structure, reliable performance, stable control and no magnetic field interference to realize the precise floating and high-precision measurement of the permanent magnet platform.

Contents of the invention

In order to avoid occupying the limited space in the vacuum chamber and minimize the impact on the platform magnetic field, it was decided to move most of the structure of the displacement mechanism out of the vacuum chamber and install it outside the lower floor of the vacuum chamber, and only extend the supporting structure of the displacement mechanism into the vacuum chamber It is used to adjust the height of the permanent magnet platform.

The following problems are faced during the design: First, the space at the bottom of the vacuum chamber is narrow and there are many equipments, how to avoid the displacement mechanism from interfering with these equipments. In order to solve this problem, the displacement mechanism is designed as a symmetrical rotator structure, which is dense and compact, and makes reasonable use of the limited space at the bottom of the bilge.

Second, how to ensure the sealing effect of the vacuum chamber while satisfying the displacement adjustment function, so as to prevent air from entering the vacuum chamber through the displacement mechanism and the through hole at the bottom of the vacuum chamber. In order to solve this problem, it was decided to use metal bellows for sealing. Metal bellows is a kind of flexible elastic, thin-walled, and transverse corrugated tube shell parts. It has both elastic characteristics and sealing characteristics. Under the action, axial, lateral, angular and combined displacements can be generated, and the sealing performance is good. The invention adopts the metal bellows formed by welding, has good elasticity, the expansion and contraction rate can reach 70%, and the sealing performance is good. The displacement mechanism includes upper flange, guide rail, lower flange, slider, support rod, screw pair, positioning ring, hand wheel, sealing device, measuring device, etc., which are installed on the outer bottom of the vacuum chamber as a whole, and only the upper end of the support rod is extended. into the vacuum chamber to adjust the height of the permanent magnet platform.

The upper flange is fixed on the outer bottom surface of the vacuum chamber, and there is a through hole in the middle for installing a linear bearing;

The guide rail is installed under the upper flange, and is connected with the upper flange by screws;

The lower flange is installed under the guide rail, and is connected with the guide rail through screws, and there is a through hole in the middle;

The slider passes through the guide rail and is located between the upper flange and the lower flange. A support rod is welded on its upper part. The support rod passes through the linear bearing in the middle of the upper flange. The three guide rails are symmetrically distributed and fixed between the upper and lower flanges. The space ensures that the support bar can only move linearly along the guide rail with the slider;

The lead screw pair includes a nut and a lead screw, the nut is fixed under the slider, and is connected with the slider through screws; the lead screw passes through the lower flange and the nut, and its lower part is welded in the through hole of the lower flange;

The handwheel is fixed at the lower end of the lead screw, and is connected with the lead screw through screws;

The positioning ring is set on the first wheel, fixed under the lower flange, and connected with the lower flange by screws to fix the lead screw;

There is a counterbore in the middle through hole of the upper flange, which can be installed with a retaining ring for fixing the linear bearing;

The sealing device includes a sealing ring and a metal bellows, the sealing ring is fixed above the upper flange; the upper end of the bellows is provided with a sleeve, which is placed on the lower end of the upper flange, and is welded to the upper flange, and a sleeve is provided at the lower end of the bellows The sleeve is set on the upper end of the slider and welded to the slider; the slider, metal bellows, upper flange, sealing ring and vacuum chamber bottom plate form a sealed cavity, which can effectively prevent air from entering the vacuum chamber;

A counterbore is provided at the lower end of the slider for placing the lead screw;

There are three through holes evenly arranged in the middle of the slider, which are used to install the linear bearing, and the linear bearing and the slider are welded and connected;

A through hole is provided on the wall of the positioning ring, which is convenient for installing the handwheel, and a threaded hole is provided on the side thereof for installing screws;

There are threaded holes on the upper flange and the side of the slider for installing the measuring device;

The measuring device is a digital display vernier caliper, and the measuring claw is provided with a through hole, and is connected with the upper flange and the slider by screws.

The beneficial effects of the invention are: the overall structure is simple and compact, and the narrow space at the bottom of the vacuum chamber is rationally utilized; the metal bellows is used for sealing, the sealing performance is reliable and stable, and the service life is long; Mechanism, three long cylindrical guide rails are symmetrically distributed, fixed between the upper and lower flanges, ensuring that the slider and the support rod welded to the slider can only move linearly along the guide rails; the ball screw is used for driving, and the operation is flexible It is simple, with high accuracy of displacement adjustment and relatively stable control. At the same time, it is equipped with a digital display measurement structure, which can accurately measure the displacement change.

Description of drawings

In order to illustrate the embodiments of the present invention more clearly, the accompanying drawings in the embodiments are briefly introduced below, which are used together with the embodiments of the present invention to explain the present invention, and do not constitute limitations to the present invention.

In the attached picture:

Fig. 1 is a kind of overall structure schematic diagram of the vacuum seal displacement mechanism that is used for superconducting maglev according to the present invention;

Fig. 2 is the sectional structural representation of upper flange in the present invention;

Fig. 3 is the cross-sectional structure schematic diagram of slider in the present invention;

Fig. 4 is the sectional structure schematic diagram of lower flange in the present invention;

Fig. 5 is the structural representation of positioning ring in the present invention;

In the figure: 1. Upper flange; 2. Guide rail; 3. Slider; 4. Lower flange; 5. Support rod; 6. Vernier caliper; 7. Metal bellows; 8. Lead screw nut; 9. Lead screw; 10. Positioning ring; 11. Hand wheel; 12. Seal ring; 13. Linear bearing; 14. Circlip ring.

Detailed ways

The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be noted that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention; the directional terms used in the present invention or The qualifiers "upper", "lower", "left", "right", "inner" and "outer" are all for the referenced drawings, and they are not used to limit the absolute position of the parts involved, but can be determined according to Circumstances vary.

As shown in Figure 2, the upper flange 1 is a cross-shaped cylindrical structure, which is fixed on the bottom of the vacuum chamber by 6 screws; there is a through hole in the center of the upper flange 1, which is used to place the linear bearing; the upper part of the through hole of the upper flange 1 has a The counterbore is used to arrange the retaining ring 14; the retaining ring 14 is used to fix the linear bearing 13. Three round holes are uniformly arranged on the bottom of the upper flange 1, and the guide rail 2 can extend into the round holes and be fixed under the upper flange 1 by screws.

As shown in Figure 3, the slider 3 is a T-shaped cylindrical structure, and three through holes are evenly arranged at the bottom for fixing the linear bearing. The linear bearing is fixed on the slider 3 by welding; the upper part of the slider 3 has a sink hole, Used to install the support rod 5; the support rod 5 passes through the linear bearing inside the upper flange 1, and the lower end extends into the counterbore on the slider 3, and is fixed on the slider 3 by welding; the linear bearing sleeve inside the slider 3 On the guide rail 2, the support rod 5 and the slide block 3 can move up and down along the guide rail. This structural design effectively utilizes the space outside the cabin, and solves the problem of bulky displacement mechanism; at the same time, this structural design uses linear bearings, which can limit the freedom of the support rod and slider on the one hand, and avoid their left and right shaking , On the other hand, it greatly reduces the frictional resistance between the structures, making the operation easier. The lower part of the slider 3 has 6 threaded holes, and the screw nut 8 is fixed below the slider 3 by screws;

As shown in accompanying drawings 4 and 5, the lower flange 4 is a cylindrical structure, and three round holes are evenly arranged on its upper part, and the guide rail 2 is inserted into the round holes, and fixed on the top of the lower flange 2 by screws; There is a through hole in the center of the flange 2, the lead screw 9 is screwed into the lead screw nut 3, and its upper end is inserted into the counterbore at the bottom of the slider 3; the disc at the lower end of the lead screw 9 extends into the center through hole of the lower flange 2 , and fixed on the lower flange 2 by welding, the lead screw 9 can freely rotate around the central axis, but cannot move up and down; there is a threaded hole in the lower part of the lower flange 2, and the positioning ring 10 is fixed below the lower flange 2 by screws; positioning There are two round holes on the side wall of the ring 10, which are used to install the hand wheel 11; the hand wheel 11 is set on the bottom of the screw, and fixed on the screw by screws. When fixing, the threaded holes on the side wall of the hand wheel 11 are aligned and positioned The through hole on the side wall of the ring 10; the cylinder on the upper part of the hand wheel 11 extends into the positioning ring 10, and there is a through hole and a threaded hole on the right side of the positioning ring 10, and the screw is passed through the through hole and screwed into the threaded hole. After the screw is tightened, The hand wheel 11 is compressed by the positioning ring 10 and cannot rotate freely, and the leading screw 9 is also fixed thereupon, thereby playing a positioning role.

As shown in accompanying drawings 1, 2 and 3, the middle part of the upper flange 1 and the lower part of the slider 3 each have a threaded hole for fixing the vernier caliper 6, and each of the two measuring claws of the vernier caliper 6 has a through hole , the screw passes through the through hole, screwed into the threaded hole, and fixes the vernier caliper on the upper flange 1 and the slider 3. The upper measuring claw of the vernier caliper 6 remains stationary with the upper flange 1, and the lower measuring claw moves up and down together with the slider 3. In actual use, shake the handwheel to move the slider 3 to the lowest position, and then press Press the zero return button of the vernier caliper to make the indication become 0, and then shake the handwheel in reverse to move the slider 3 upwards. At this time, the indication of the vernier caliper is the displacement of the slider 3.

As shown in attached drawings 1, 2, and 3, there is a circular groove in the middle of the upper flange 1, which is used to place a sealing ring to prevent outside air from entering the vacuum chamber from the contact surface between the upper flange 1 and the bottom of the vacuum chamber ;The lower part of the upper flange 1 and the upper part of the slider 3 each have a cylindrical boss, the sleeve of the bellows 7 is placed on the boss, and the bellows is fixed on the upper flange 1 and the slider 3 by welding , to ensure that the outside gas cannot enter the vacuum chamber during the movement of the slider 3 .

As a preferred embodiment of the present invention, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention, which is also part of the present invention. protected range. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this description is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the description is only for clarity, and those skilled in the art should regard the description as a Overall, the technical solutions in the embodiments can also be appropriately modified to form other implementations that can be understood by those skilled in the art.

Claims (3)

1. a kind of manual height-adjustable vacuum sealing displacement mechanism for the small force measuring device of super-conductive magnetic suspension, mainly Including upper flange, guide rail, lower flange, sliding block, supporting rod, lead screw pair, locating ring, handwheel, metal bellows and sealing ring etc., It is characterized in that overall structure is symmetrical revolving body, upper flange, guide rail and sliding block are fixed together, and sliding block is placed in across guide rail It between upper and lower flange, can move up and down along guide rail, upper end of slide block welds supporting rod, and lower end connects lead screw pair, passes through leading screw Nut adjusts supporting rod displacement, and overall structure is intensive compact.In addition, entire gearshift is removed vacuum chamber, it is mounted on true Outside empty Ceiling, air is completely cut off by metal bellows and sealing ring, to ensure the vacuum degree of vacuum chamber, doing so can be with It avoids occupying the confined space in cabin, while also avoiding a large amount of metal structure and having an adverse effect simultaneously greatly to the magnetic field in cabin It is big to reduce eddy-current loss.

2. according to claim 1 a kind of for the manual height-adjustable true of the small force measuring device of super-conductive magnetic suspension Sky sealing displacement mechanism, which is characterized in that use the high compact axial symmetry variable displacement mechanism based on more guide rods, three oval Column lead rail axis is symmetrical, passes through the through-hole on sliding block, is fixed between lower flange, strictly limits the degree of freedom of sliding block, It ensure that the straightness of sliding block when moving.

3. according to claim 1 a kind of for the manual height-adjustable true of the small force measuring device of super-conductive magnetic suspension Sky sealing displacement mechanism, which is characterized in that be sealed using metal bellows and sealing ring, the upper and lower ends of metal bellows It is respectively welded on upper flange and sliding block, sealing ring is then placed in the junction of upper flange and vacuum Ceiling, metal bellows, cunning Block, sealing ring, upper flange and vacuum chamber bottom plate form a closing chamber, can effectively prevent air from entering vacuum chamber, sealing can By property height.