KR20230144348A - Anode rotating type x-ray tube having liquid metal lubricated sliding bearing - Google Patents

Abstract

The present invention relates to a bipolar rotating X-ray tube equipped with an improved liquid metal lubricated sliding bearing to reduce the sliding average coefficient of friction and allow rapid heat dissipation.
The present invention includes a vacuum tube whose inner space is in a vacuum state, an anode assembly disposed in the inner space of the vacuum tube and emitting X-rays when electrons collide, and a liquid metal lubricated sliding bearing that rotatably supports the anode assembly. In the anode rotating X-ray tube, the liquid metal lubricated sliding bearing includes a bearing housing, a rotating shaft rotating within the bearing housing, and liquid metal filled between the rotating shaft and the bearing housing, A bipolar rotating X-ray tube is provided with a liquid metal lubricated sliding bearing having a plurality of surface texturing patterns formed on at least one of the outer peripheral surface of the rotating shaft and the upper and lower surfaces of the fixed flange of the rotating shaft.

Description

{ANODE ROTATING TYPE X-RAY TUBE HAVING LIQUID METAL LUBRICATED SLIDING BEARING}

The present invention relates to an anode rotating It is about a rotating X-ray tube.

Currently, parts operating in extreme environments are artificially provided with lubricant and surface roughness to reduce friction generated at the relative sliding contact surface, and much research is being conducted on the durability of the parts resulting from this.

In particular, it is known that research is being conducted on friction reduction and durability by coating balls or races with solid lubricants such as lead (Pb) or silver (Ag) in a vacuum atmosphere.

However, at operating temperatures above 350°C, lead (Pb) and silver (Ag) evaporate and seize, thereby losing their role as a solid lubricant.

To solve these problems, metal lubricated bearings that can be used at high temperatures have been studied.

However, Galinstan alloy (an alloy of Ga-In-Sn that is liquid at room temperature), a liquid metal lubricant that ensures smooth operation and characteristics in high-temperature metal lubricated bearings, is mainly used.

However, due to the high coefficient of friction, it has limited application.

Meanwhile, when electrons collide with a target at high speed, X-rays are emitted, and an X-ray tube is used to intentionally emit the X-rays.

In this X-ray tube, electrons are accelerated by the potential difference between the anode and the cathode and collide with the target. Since more than 99% of the electric power input to form the potential difference is converted into heat, High heat is generated, which limits the power input to the X-ray tube.

The anode rotating X-ray tube is an

In such an anode rotating X-ray tube, the target generates heat at a high temperature due to collision with electrons, and the heat is transferred to the bearing assembly that supports the rotation of the anode, forming a ball or roller-shaped bearing rotor and Wear of the bearing race in contact with the bearing rotating body is accelerated, durability of the bearing is reduced, noise increases when the anode rotates at high speed, high-speed rotation becomes difficult, and ultimately the target is damaged.

In order to solve this problem, a bearing assembly has been designed that improves the durability of the bearing assembly by promoting heat dissipation of the bearing assembly.

That is, the bearing assembly includes a bearing housing at the upper end, a bearing outer ring inserted inside the bearing housing, a rotating shaft inserted inside the bearing outer ring, and a plurality of bearings interposed between the rotating shaft and the bearing outer ring. It is comprised of a rotating body and at least one heat-conducting member made of a material with higher thermal conductivity than the bearing housing to discharge heat from the bearing housing to the outside.

The bearing assembly configured in this way quickly dissipates the generated heat to the outside through the heat conduction member.

Accordingly, wear of the bearing rotor and the bearing race in contact with it is alleviated, and the durability of the parts constituting the bearing assembly, such as the bearing rotor and the bearing outer ring, and the bearing assembly itself is improved.

This anode rotating X-ray tube is disclosed in Patent Registration No. 10-1759090 (registered on July 12, 2017).

However, the conventional bearing assembly configured and functioning as described above requires installing a plurality of heat-conducting members in the bearing housing, which makes the structure of the bearing assembly complicated, difficult to manufacture, and increases cost.

Furthermore, in a bearing assembly rotating at high speed, friction occurs as the rotating shaft rotates at high speed, which not only generates high heat but also causes wear on the rotating shaft, bearing rotor, and outer ring.

Accordingly, the durability of the conventional bearing assembly is reduced, ultimately shortening the lifespan of the bearing assembly.

In addition, as a prior document related to the present invention described later, there is a control method of a radiation tomography device and a radiation tomography device and program of Japanese Patent No. 5815626 (registered on October 2, 2015).

The X-ray tube of the above-mentioned prior literature includes a rotor that rotates while supporting the anode, a groove bearing that rotates within the rotor, and a liquid metal lubricant (or liquid metal bearing) filled between the rotor and the groove bearing. .

However, if the liquid metal lubricant or the oil film of the liquid metal lubricant is lost from the flange that secures the groove bearing to the rotor, the X-ray tube (including the ) This groove bearing is separated from the rotor or is moved out of its original position.

As a result, the groove bearing and surrounding parts of the groove bearing are damaged, ultimately shortening the life of the bearing.

The present invention was created to solve the above problems, and is a liquid metal lubricated sliding bearing that reduces the average sliding friction coefficient of the rotating shaft flange of the bearing and allows heat to be quickly dissipated to extend the life of the bearing. The purpose is to provide a bipolar rotating X-ray tube equipped with this.

The anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing of the present invention to achieve the above object,

An anode assembly comprising a vacuum tube whose inner space is in a vacuum state, an anode assembly disposed in the inner space of the vacuum tube and emitting X-rays when electrons collide, and a liquid metal lubricated sliding bearing that rotatably supports the anode assembly. In a typical X-ray tube,

The liquid metal lubricated sliding bearing includes a bearing housing, a rotating shaft rotating within the bearing housing, and liquid metal filled between the rotating shaft and the bearing housing,

A plurality of surface texturing patterns are formed on at least one of the outer peripheral surface of the rotating shaft and the upper and lower surfaces of the fixing flange of the rotating shaft.

In the present invention, the surface texturing pattern is formed by continuously repeating 'V' grooves of a predetermined depth up, down, left, and right, and the 'V' grooves are formed on one side as an inclined surface dug at a predetermined inclination angle, The other end of the inclined surface is formed as a vertical plane up to the surface of the fixing flange.

In the present invention, the inclination angle is preferably 30 to 45 degrees, the angle between the 'V' is preferably 120 to 135 degrees, and the width and depth of the 'V' groove are 90 to 110㎛. Preferably, the 'V' shaped grooves are preferably formed at intervals of 100 to 500㎛.

In the present invention, the surface texturing pattern is formed by electrical discharge machining.

In the present invention, the rotating shaft has an upper end closed and a lower end open so that heat is emitted, and a heat dissipation space is formed therein, and the heat dissipation space is provided with at least one heat dissipation means for dissipating heat. , the heat dissipation means is made of a metal heat dissipation member fixed to the wall of the heat dissipation space, and the metal heat dissipation member is fixedly installed over the entire circumference of the wall of the heat dissipation space.

In the present invention, the metal heat dissipation member is made of either Cu or Al thin plates, and the metal heat dissipation member is made of a zigzag integrated form in which metal plates are repeated.

In the present invention, two or more zigzag integrated metal heat dissipating members are provided radially, wherein the zigzag integrated metal heat dissipating members include: a first metal heat dissipating member fixed to the wall of the heat dissipating space; a support member supported and in close contact with an outer end of the first metal heat dissipation member; and a second metal heat dissipation member fixed to the wall of the support member.

According to an embodiment of the present invention, an oil film of liquid metal can be continuously maintained by repeatedly forming a surface texturing pattern on the outer surface of a rotating shaft rotating at high speed and the upper and/or lower surfaces of the fixed flange on the rotating shaft.

Therefore, the average sliding friction coefficient of liquid metal lubricated sliding bearings can be reduced.

Accordingly, high friction can be prevented during the operation of the liquid metal lubricated sliding bearing, and lubrication performance can be continuously maintained during the operation of the liquid metal lubricated sliding bearing.

In addition, by providing a metal heat dissipation member fixed to the wall of the heat dissipation space of the rotating shaft rotating at high speed as a heat dissipation means, heat generated in the liquid metal lubricated sliding bearing or X-ray tube can be quickly dissipated to the outside.

Therefore, the heat generated in the liquid metal lubricated sliding bearing can be reduced, the lifespan of the liquid metal lubricated sliding bearing can be extended, and the performance of the liquid metal lubricated sliding bearing can be improved.

In addition, an oil film of liquid metal can be continuously maintained on the fixed flange operating in a vacuum atmosphere, allowing the rotating shaft to rotate quietly in its original position without the fixed flange being separated from the bearing housing.

Therefore, the rotating shaft of the liquid metal lubricated sliding bearing can be used continuously in a vacuum atmosphere.

In addition, even if the heat generated from the anode assembly including the target when emitting .

Figure 1 is a cross-sectional view of an anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing according to the present invention.
Figure 2 is a detailed cross-sectional view of the liquid metal lubricated sliding bearing of Figure 1.
Figure 3 is an external perspective view of the rotating shaft of Figure 2 according to an embodiment of the present invention.
Figure 4 is an external perspective view of the rotating shaft of Figure 2 according to another embodiment of the present invention.
Figure 5 is a detailed view of the main portion of the surface texturing pattern of Figures 3 and 4;
Figure 6 is a cross-sectional view taken along line AA in Figure 5.
Figure 7 is a perspective view showing in detail the metal heat dissipation member that is the heat dissipation means of Figures 1 and 2.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings.

Figure 1 shows a cross-sectional view of a bipolar rotating X-ray tube equipped with a liquid metal lubricated sliding bearing according to the present invention.

And FIG. 2 shows a detailed cross-sectional view of the liquid metal lubricated sliding bearing of FIG. 1.

Additionally, FIG. 3 shows an external perspective view of the rotating shaft of FIG. 2 according to one embodiment of the present invention, and FIG. 4 shows an external perspective view of the rotating shaft of FIG. 2 according to another embodiment of the present invention.

In addition, FIG. 5 shows a detailed view of the main portion of the surface texturing pattern of FIGS. 3 and 4, and FIG. 6 shows a cross-sectional view taken along line A-A in FIG. 5.

1 to 6, the anode rotating X-ray tube 200 equipped with a liquid metal lubricated sliding bearing according to the present invention is an X-ray tube device ( (not shown) is inserted into the inside of the device to generate and emit X-rays, and as shown in FIG. 1, it includes a vacuum tube 201, a cathode assembly 220, and an anode assembly. It is composed of an assembly (210), a liquid metal lubricated sliding bearing (100), a rotor (250), and a stator (not shown).

And the anode rotating X-ray tube 200 equipped with a liquid metal lubricated sliding bearing according to the present invention connects the anode assembly 210 to the liquid metal lubricated sliding bearing 100 to rotate the anode assembly 210. It is composed of a connecting shaft 230 and a connecting member 230a.

In addition, since the anode rotary X-ray tube 200 equipped with a liquid metal lubricated sliding bearing according to the present invention is inserted and installed into a space filled with cooling oil inside the is surrounded by cooling oil, and the internal space is maintained in a high vacuum state.

This vacuum tube 201 is made of a metal material.

And the cathode assembly 220 is fixed to the upper side of the vacuum tube 201, and generates electrons and projects them into the vacuum tube 201. Approximately 150V is applied between the filament and the target, which will be described later. It contains a cathode that forms a potential difference of (volt).

This cathode assembly 220 is sealed and coupled to the vacuum tube 201, and is made of a ceramic material such as, for example, alumina (Al2O3).

In addition, the anode assembly 210 is a disk-shaped member and is composed of a target and a substrate with which electrons generated in the filament collide at high speed.

And the liquid metal lubricated sliding bearing 100 includes a bearing housing, a rotating shaft 115 rotating within the bearing housing, and a liquid metal (or liquid metal bearing) filled between the rotating shaft 115 and the bearing housing. , or liquid metal lubricant) (LM; Liquid Metal, 101).

The liquid metal 101 is a Ga-In-Sn (gallium-indium-tin) alloy with a purity of 99.99%, and specifically contains 68.5 wt% of Ga, 21.5 wt% of In, and 10 wt% of Sn. .

The temperature of the Ga-In-Sn alloy is maintained at 22-27°C.

In addition, a fixed flange 115b is formed at approximately the middle portion of the rotating shaft 115 so that the rotating shaft 115 can always rotate at a certain position within the bearing housing.

In addition, as shown in FIG. 2, inside the rotating shaft 115, a heat dissipation space 115a is formed where the upper end is closed and the lower end is open so that heat of the rotating shaft 115 is dissipated.

Therefore, heat from the rotating shaft 115 can be discharged to the outside through the heat dissipation space 115a.

This rotating shaft 115 may be made of stainless steel.

And the bearing housing includes an upper housing 113 accommodating the upper part of the fixed flange 115b, a lower housing 123 accommodating the lower part of the fixed flange 115b, and a rotating shaft below the fixed flange 115b ( It includes a flange support housing 119 that supports 115) and is connected to the lower housing 123, and a flange housing 117 installed on the outer periphery of the fixed flange 115b to accommodate the fixed flange 115b. .

In addition, the liquid metal lubricated sliding bearing 100 includes an outer case 111 that supports the upper housing 113 and accommodates the constituent members of the lower part of the upper housing 113, and supports the flange support housing 119. It is provided with an inner case 121 that accommodates the constituent members of the lower part of the flange support housing 119, and a lower case 125 that supports the lower housing 123 and accommodates the lower housing 123.

Meanwhile, the liquid metal lubricated sliding bearing 100 configured as described above is not limited to components other than the rotating shaft 115.

This is because the configuration of the liquid metal lubricated sliding bearing 100 other than the rotating shaft 115 may vary depending on the device to which the liquid metal lubricated sliding bearing 100 is applied.

Therefore, the anode rotating X-ray tube 200 equipped with a liquid metal lubricated sliding bearing according to the present invention is not limited to the configuration shown in FIGS. 1 and 2.

In addition, as shown in FIGS. 3 and 4, a plurality of surface texturing is applied to at least one of the surface of the outer peripheral surface of the rotary shaft 115 and the upper and lower surfaces of the fixing flange 115b of the rotary shaft 115. A surface texturing pattern 103 is formed.

As shown in FIGS. 5 and 6, this surface texturing pattern 103 is formed by continuously repeating 'V'-shaped grooves 103a of a predetermined depth up, down, left, and right.

One side of the 'V'-shaped groove 103a of the surface texturing pattern 103 is formed with an inclined surface 103b cut at a predetermined inclination angle α, and the other end of the inclined surface 103b is a fixed flange 115b. It is formed as a vertical surface (103c) up to the outer surface of.

At this time, the inclination angle (α) is preferably set to 30 to 45 degrees.

When the inclination angle (α) is 30 degrees or less, the liquid metal (LM, 101) can easily flow into the inclined surface (103b), but there is a problem that it may flow back, and when the inclination angle (α) is 45 degrees or more, the liquid metal (LM, 101) can easily flow into the inclined surface (103b). In this case, there is a problem in that the liquid metal (LM, 101) cannot easily flow into the inclined surface (103b) and stagnates in the 'V' groove (103a).

Therefore, when the inclination angle (α) is 30 to 45 degrees, it is advantageous for the formation of an oil film by the liquid metal (LM, 101).

In addition, it is preferable that the included angle θ of the 'V' shaped groove 103a is 120 to 135 degrees.

When the included angle (θ) is set to 120 degrees or less, there is a problem in that it is difficult to form a lubricant film of the liquid metal, and when the included angle (θ) is set to 135 degrees or more, the low holding power of the liquid metal increases, resulting in loss of the liquid metal. There is a problem with loss.

And the width (W1) and depth (h) of the 'V' shaped groove (103a) are preferably formed to be 90 to 110㎛.

When the width (W1) and depth (h) of the 'V' groove (103a) are formed to be 90㎛ or less, liquid metal (LM, 101) can easily flow in or out of the 'V' groove (103a). Otherwise, if the width (W1) and depth (h) of the 'V' groove (103a) are formed to be 110㎛ or more, the liquid metal (LM, 101) is pooled in the 'V' groove (103a). There is a problem that the fluidity of liquid metal (LM, 101) is low.

Additionally, the 'V' shaped grooves 103a are preferably formed at intervals of 100 to 500㎛ (W2).

When the 'V' grooves (103a) are formed at intervals (W2) of 100㎛ or less, the number of 'V' grooves (103a) formed increases, and the fluidity of the liquid metal (LM, 101) decreases, and the When the 'V' shaped grooves 103a are formed at intervals W2 of 500 ㎛ or more, the effect of forming the surface texturing pattern 103 is reduced.

Therefore, the 'V' shaped grooves 103a are most advantageous for forming an oil film of liquid metal (LM, 101) when they are formed at intervals of 100 to 500㎛ (W2).

And the surface texturing pattern 103 is formed by electrical discharge machining. This type of electrical discharge machining is easy to process and has low processing costs.

On the other hand, the existing surface texturing pattern relied on rolling processing, which requires a lot of processing costs, and rolling processing is used to create the pattern 103 of the 'V' groove 103a applied in the present invention with the dimensions described above. It is difficult to process as well.

Meanwhile, the surface texturing pattern 103 is limited to a 'V' shaped groove 103a or a herringbone groove pattern, but dimples may be formed repeatedly.

However, the V'-shaped groove pattern 103 is superior to the dimple in terms of processability and friction coefficient reduction.

In particular, the 'V' groove pattern 103 applied to the present invention has an excellent lubricant reserve effect even in boundary lubrication.

On the other hand, drawing number 111a, which is not explained in the drawing, indicates a cover fixing member for checking the inside of the external case 111 and fixing the upper housing 113.

FIG. 7 shows a detailed perspective view of the metal heat dissipation member, which is the heat dissipation means of FIGS. 1 and 2.

Referring to FIGS. 1, 2, and 7, the heat dissipation space 115a of the rotating shaft 115 is provided with at least one heat dissipation means for dissipating heat.

This heat dissipation means consists of a metal heat dissipation member 130 fixed to the wall of the heat dissipation space 115a.

As shown in FIG. 3, the metal heat dissipation member 130 is fixedly installed around the entire wall of the heat dissipation space 115a, and is made of a zigzag integrated form in which metal plates are repeated.

In particular, two or more zigzag integrated metal heat dissipation members 130 are provided radially (or radially). That is, the zigzag integrated metal heat dissipation member 130 is in close contact with the first metal heat dissipation member 131 fixed to the wall of the heat dissipation space 115a and the outer end of the first metal heat dissipation member 131. It includes a supported support member 133 and a second metal heat dissipation member 135 fixed to the inner wall of the support member 133.

As shown in FIGS. 1 and 2, the installed number of the first and second metal heat dissipation members 131 and 135 is three, but the length of the rotating shaft 115, the size of the heat dissipating space 115a, or/ And it may vary depending on the degree of heat generated in the rotating shaft 115.

Additionally, the reason the first and second metal heat dissipation members 131 and 135 are formed in a zigzag shape is to maximize the heat dissipation area.

Therefore, it is preferable that the zigzag spacing (or angle) of the first and second metal heat dissipation members 131 and 135 be as close as possible to the extent that it does not interfere with heat dissipation.

Although not shown in the drawing, the metal heat dissipation member 130 may be formed in a coil shape. The reason is that the coil shape allows the heat dissipation area to be as large as possible.

The first and second metal heat dissipation members 131 and 135 and the support member 133 may be made of either Cu or Al thin plates with a thickness of 0.1 to 0.3 mm, which have relatively excellent heat dissipation performance.

As described above, the anode rotating X-ray tube 200 equipped with a liquid metal lubricated sliding bearing according to the present invention is, first, as shown in FIGS. 3 to 6,

In addition, as shown in FIG. 7, a metal heat dissipation member 130 fixed to the wall of the heat dissipation space 115a of the rotating shaft 115 rotating at high speed is provided as a heat dissipation means.

Therefore, the heat generated in the liquid metal lubricated sliding bearing 100 or the device to which the liquid metal lubricated sliding bearing 100 is applied (for example, devices in the aerospace field and rotating anode X-ray tube, etc.) can be quickly released to the outside. You can.

Accordingly, the performance of the liquid metal lubricated sliding bearing 100 can be continuously maintained, the lifespan of the liquid metal lubricated sliding bearing 100 can be extended, and the liquid metal lubricated sliding bearing 100 can be maintained continuously even in a high temperature vacuum atmosphere. You can use it.

Therefore, the rotating shaft 115 of the anode rotating X-ray tube 200 equipped with the liquid metal lubricated sliding bearing according to the present invention can be continuously used in a vacuum atmosphere.

In addition, even if the heat generated from the anode assembly including the target when emitting .

As described above, the present invention has been described with reference to an embodiment shown in the drawings, but this is merely illustrative, and various modifications and equivalent embodiments can be made by those skilled in the art. You will understand.

Therefore, the true scope of protection of the present invention should be determined only by the appended claims.

100. Liquid metal lubricated sliding bearing
101. Liquid metal
103. Surface texturing patterns
103a. 'V' shaped groove
103b. incline
103c. vertical plane
113. Upper housing
115. Rotating shaft
115a. heat dissipation space
115b. fixed flange
123. Lower housing
130. Metal heat dissipation member
131. First metal heat dissipation member
133. Support members
135. Second metal heat dissipation member
200. Anode rotating X-ray tube
201. Vacuum tube
210. Anode assembly
220. Cathode assembly
230. Connecting shaft
230a. connection member
250. Rotor

Claims (14)

An anode assembly comprising a vacuum tube whose inner space is in a vacuum state, an anode assembly disposed in the inner space of the vacuum tube and emitting X-rays when electrons collide, and a liquid metal lubricated sliding bearing that rotatably supports the anode assembly. In a typical X-ray tube,
The liquid metal lubricated sliding bearing includes a bearing housing, a rotating shaft rotating within the bearing housing, and liquid metal filled between the rotating shaft and the bearing housing,
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, characterized in that a plurality of surface texturing patterns are formed on at least one of the outer peripheral surface of the rotating shaft and the upper and lower surfaces of the fixed flange of the rotating shaft. According to paragraph 1,
The surface texturing pattern is a bipolar rotating According to paragraph 2,
The 'V' shaped groove is formed as an inclined surface dug at a predetermined inclination angle on one side, and the other end of the inclined surface is a bipolar rotary type equipped with a liquid metal lubricated sliding bearing, characterized in that it is formed as a vertical surface up to the surface of the fixed flange. X-ray tube. According to paragraph 3,
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, wherein the inclination angle is 30 to 45 degrees. According to paragraph 2,
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, characterized in that the angle between the 'V' shape is 120 to 135 degrees. According to paragraph 2,
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, characterized in that the width and depth of the 'V' shaped groove are formed at 90 to 110㎛. According to paragraph 2,
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, wherein the 'V' shaped grooves are formed at intervals of 100 to 500㎛. According to paragraph 1,
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, wherein the surface texturing pattern is formed by electrical discharge machining. According to paragraph 1,
The rotating shaft has an upper end closed to dissipate heat and a lower end open to form a heat dissipation space inside,
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, characterized in that the heat dissipation space is provided with at least one heat dissipation means for dissipating heat. According to clause 9,
The heat dissipation means consists of a metal heat dissipation member fixed to the wall of the heat dissipation space,
An anode rotating X-ray tube with a liquid metal lubricated sliding bearing, wherein the metal heat dissipation member is fixedly installed around the entire wall of the heat dissipation space. According to clause 10,
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, wherein the metal heat dissipation member is made of one of Cu and Al thin plates. According to clause 10,
The metal heat dissipation member is a bipolar rotating According to clause 12,
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, characterized in that two or more zigzag integrated metal heat dissipation members are provided radially. According to clause 12,
The zigzag integrated metal heat dissipation member,
a first metal heat dissipation member fixed to a wall of the heat dissipation space;
a support member supported and in close contact with an outer end of the first metal heat dissipation member;
An anode rotating X-ray tube equipped with a liquid metal lubricated sliding bearing, comprising: a second metal heat dissipation member fixed to the wall of the support member.

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