Vacuum interrupter tube

Abstract

The invention relates to a vacuum interrupter tube (10), comprising at least one insulating body (20), a fixed contact (30), a fixed contact flange (40), a moving contact (50) having a longitudinal axis (56) of the moving contact (50), a moving contact flange (60), a moving contact bearing (70), and a bellows (80), wherein the fixed contact (30) is stationarily arranged in the fixed contact flange (40), the moving contact (50) is moveably guided in the moving contact bearing (70) and the moving contact is moveably secured to the moving contact flange (60) by the bellows (80), wherein the bellows (80) is secured to the moving contact flange (60) by a first bellows end (82) and the bellows (80) is secured to the moving contact (50) by a second bellows end (84), wherein an increased pressure resistance of the vacuum interrupter tube (10) against ambient pressures over 1 bar is achieved by a sleeve (90) which is secured to the moving contact (50) against movements along the longitudinal axis (56) of the moving contact (50), and which is guided through the moving contact bearing (52).

Description

[0001] The invention relates to a vacuum interrupter for medium-voltage switchgear and high-voltage systems.

[0002] State-of-the-art vacuum interrupters have a bellows to guide the moving contact of the vacuum interrupter movably into the vacuum interrupter.

[0003] For large strokes and / or long bellows, especially at ambient pressures above one bar (1 bar), the problem arises that the bellows becomes deformed during switching operations, for example, it buckles, bends, and / or twists, and rubs against the moving contact. This reduces the service life of the bellows and thus that of the vacuum interrupter.

[0004] From JP2011054504A, an interrupter is known which provides additional sealing means in order to reduce the pressure on the bellows of the moving contact and thus ensures a higher pressure resistance of the vacuum interrupter.

[0005] DE102016002261A1 discloses a switch with a vacuum interrupter and an exclusively linear guidance of the switching rod by means of a movable body which engages in a groove.

[0006] DE112011105304T5 discloses an inwardly bent moving contact flange in conjunction with a guide around the moving contact.

[0007] JP S52137073U shows a vacuum interrupter with a moving contact rod surrounded by a shaft which is guided by a bearing on the moving contact flange and prevents rotation of the shaft by means of a pin.

[0008] JP2005339865A discloses an outwardly bent moving contact flange in conjunction with a guide around the moving contact.

[0009] From EPO641001A1 a sliding body is known which is arranged on a moving contact rod and is guided in a bushing.

[0010] US4492837A discloses a guide for a moving contact rod for a vacuum interrupter, wherein the guide is formed from a guide means on the moving contact flange and a shrunk-on coating on the moving contact rod.

[0011] The object of the invention is to reduce or prevent deformation of the bellows and friction of the bellows on the moving contact.

[0012] The problem is solved by independent claim 1 and the claims dependent thereon.

[0013] In one embodiment, the vacuum interrupter comprises at least one insulating body, a fixed contact, a fixed contact flange, a moving contact with a longitudinal axis of the moving contact, a moving contact flange, a moving contact bearing, and a bellows. The fixed contact is arranged in a stationary manner in the fixed contact flange, the moving contact is movably guided in the moving contact bearing, and the moving contact is movably fastened to the moving contact flange by the bellows. The bellows is fastened to the moving contact flange with a first bellows end, and the bellows is fastened to the moving contact with a second bellows end. A sleeve fixed to the moving contact against movement along the longitudinal axis of the moving contact and guided by the moving contact bearing achieves increased compressive strength of the vacuum interrupter against ambient pressures above 2 bar. In particular, increased compressive strength of the vacuum interrupter against ambient pressures above 4 bar is also achieved.

[0014] The fixation of the sleeve to the moving contact ensures that the bellows is protected in every switch position and that even when the contact system consisting of the fixed contact and the moving contact is closed, there is no possibility of frictional contact between the bellows and the moving contact or of deformation of the bellows. This also leads to a longer service life at elevated ambient pressures. Increased ambient pressures tend to occur when the vacuum interrupter is arranged in a gas under excess pressure, in particular an insulating gas, particularly preferably a gas with a GWP (Global Warming Potential) lower than that of SF6. In particular, the gas with which the switchgear is filled can be a ketone, in particular a fluoroketone, a nitrile, or a gas mixture with nitrogen and carbon dioxide.

[0015] The sleeve is preferably designed such that it has an inner contour that replicates the outer contour of the moving contact in the area in which the sleeve is attached to the moving contact.

[0016] In an advantageous embodiment, the sleeve is also designed in such a way that the distance between the sleeve and the bellows is small when assembled.

[0017] The sleeve is arranged on the moving contact in such a way that the sleeve extends from the second bellows end through the moving contact bearing and that the sleeve is fixed to the moving contact by means of a fastening means in such a way that when the moving contact moves, no relative movement along the longitudinal axis of the moving contact occurs between the moving contact and the sleeve.

[0018] The moving contact has at least one moving contact rod and one moving contact disc, and the second bellows end is connected to the moving contact rod via a bellows cap. A moving contact body can also be arranged between the moving contact rod and the moving contact disc.

[0019] The sleeve in the area of ​​the second bellows end and / or in the area of ​​the bellows cap is fixed in position on the moving contact by means of a press fit. Alternatively, the sleeve is attached to a thickened portion of the moving contact that is not replicated by the sleeve by means of latching, locking, soldering, welding, or pressing.

[0020] It is also particularly preferred that the sleeve be press-fitted between the second bellows end and the moving contact or between the bellows cap and the moving contact rod. In particular, the sleeve can also be additionally latched to structural elements on the second bellows end, the moving contact, or the bellows cap. Interlocking projections and / or recesses are particularly suitable for latching.

[0021] It is also preferred that the moving contact bearing has a first guide element and that the sleeve has a second guide element, wherein the first guide element and the second guide element engage with each other in such a way that rotation of the sleeve in the moving contact bearing is prevented. In particular, interlocking tongue and groove designs are suitable, i.e. the first guide element is, for example, a groove and the second guide element is, for example, a protruding structural element, a groove engagement, such as a tongue, or vice versa. The structural element can be either rigid, inflexible, or flexible. The interaction of the first guide element and the second guide element thus prevents rotation of the sleeve in the moving contact bearing.

[0022] It is further preferred that the sleeve has more than one first guide element, in particular two or three first guide elements, and that the moving contact bearing has more than one second guide element, in particular two or three second guide elements. The corresponding guide elements engage with each other, i.e., a first guide element and a second guide element interact, so that two, three, or more first guide elements and second guide elements ensure secure guidance and thus effective anti-rotation protection between the moving contact bearing and the sleeve.

[0023] It is also preferred that the first guide element and the second guide element engage with each other and mutually limit their movement in such a way that the sleeve does not slide out of the moving contact bearing. For example, this is possible by limiting the longitudinal extent of the groove parallel to the longitudinal axis of the moving contact, i.e. in this example the groove engagement, e.g. a spring, abuts the end of the groove and thus does not allow any further movement of the sleeve and the moving contact connected to the sleeve. This can prevent the bellows from being overstretched, for example during transport, due to overstretching when the sleeve with the moving contact slips out of the moving contact bearing, since the movement is limited by the first guide element and the second guide element.The sleeve therefore not only reduces the risk of deformation and thus higher ambient pressures and / or longer bellows strokes and lengths, but also protects against damage to the bellows due to overstretching of the bellows.

[0024] It is also preferred that the moving contact rod has a third guide element and the sleeve has a fourth guide element, which cooperate in such a way that rotation of the sleeve on the moving contact rod is prevented.

[0025] In particular, it is preferred that the third guide element is formed by a flattened region on the circumference of the moving contact rod, in particular of the moving contact, and that the fourth guide element is formed by a raised flattened portion in the sleeve that fills the region with the flattened portion of the moving contact rod or the moving contact. Alternatively, the moving contact rod can also have, entirely or partially, an elliptical circumferential profile, an elliptical cross-sectional area, and the sleeve can have an elliptical circumferential profile, an elliptical cross-sectional area.

[0026] It is further preferred that the moving contact rod has more than one third guide element, in particular two or three third guide elements, and that the sleeve has more than one fourth guide element, in particular two or three fourth guide elements. The corresponding guide elements engage with each other, i.e., a third guide element and a fourth guide element interact, so that two, three, or more third guide elements and fourth guide elements ensure secure guidance and thus effective protection against twisting between the moving contact and the sleeve.

[0027] By using the first guide element, the second guide element, the third guide element and the fourth guide element or multiples of these, in addition to reducing the deformation risks of the bellows due to the sleeve, the deformation risk due to torsions of the bellows is also reduced.

[0028] It is also preferred that the sleeve be made of a material with a low coefficient of friction. In particular, it is preferred that the coefficient of friction for static friction and the coefficient of friction for sliding friction are both small, and particularly preferably, the coefficients of friction for static friction and sliding friction are equal, thereby enabling smooth starting and stopping.

[0029] It is further preferred that the sleeve is made of polytetrafluoroethylene or a modification of polytetrafluoroethylene, i.e. a chemically related material.

[0030] It is also advantageous if the second bellows end and / or the bellows cap also have a bellows shield. The bellows shield prevents and / or reduces the buildup of vaporized materials on the bellows.

[0031] It is further preferred that the bellows shield extends from the second bellows end in the direction of the moving contact flange.

[0032] The invention is explained below with reference to figures. Figure 1: Section through a vacuum interrupter with a sleeve according to the invention; Figure 2: Section through a moving contact rod with a sleeve and bellows cap with a bellows shield; Figure 3: Perspective view of a guided sleeve in a moving contact bearing; Figure 4: Perspective view of a moving contact with a sleeve and guide elements.

[0033] The Figure 1 shows a section through a vacuum interrupter 10 with a sleeve 90 according to the invention. The vacuum interrupter 10 has insulating elements 20, which are optionally spaced apart in the area of ​​the contact disks by an intermediate element 25.

[0034] Furthermore, the vacuum interrupter 10 has a fixed contact 30, here consisting of a fixed contact rod 32, a fixed contact body 35 and a fixed contact disc 34. The fixed contact 30 is attached to an insulating body 20 at one end of the vacuum interrupter 10 by means of a fixed contact flange 40.

[0035] A moving contact 50 of the vacuum interrupter 10 is arranged opposite the fixed contact 20, wherein the moving contact 50 here consists, for example, of a moving contact rod 52, a moving contact body 55 and a moving contact disc 54.

[0036] A sleeve 90 is attached to the moving contact 50, more precisely to the moving contact rod 52, and this sleeve 90 is guided out of the bellows by a moving contact bearing 70 on the moving contact flange 60. In the example shown here, the sleeve 90 is pressed tightly between the moving contact rod 52 and the bellows cap 86. This fixes the sleeve 90 on the moving contact 52 in such a way that, when the moving contact 50 moves along the longitudinal axis 56 of the moving contact 50, no relative movement occurs between the sleeve 90 and the moving contact 50. The bellows 80, which enables movement of the moving contact 50 within the vacuum interrupter 10, is attached to the moving contact flange 60 by a first end 82 of the bellows 80. The second end 84 of the bellows 80 is attached to the bellows cap 86 in Figure 1 and the bellows cap 86 is in turn attached to the moving contact rod 52 of the moving contact 50. The bellows cap 86 has in the Figure 1via an optional bellows shield 88, which extends from the bellows cap 86 along the bellows 80 in the direction of the moving contact flange 60.

[0037] The Figure 2 shows a moving contact rod 52 with a sleeve 90, which is pressed in the direction of arrow 91 into the press-in area 89 between the moving contact rod 52 and the bellows cap 86. Optionally, this press-in area 89 can also be formed by a thickening of the moving contact rod. Furthermore, the bellows cap 86 has a bellows shield 88, as shown in the Figure 1 is shown.

[0038] The Figure 3 shows a part of a moving contact rod 52 with a third guide element 53, a sleeve 90 with a fourth guide element 94 and a second guide element 92 in the sleeve 90, which is connected to the one not shown here, but in Figure 4 , shown first guide element 72 of the moving contact bearing 70.

[0039] The Figure 4shows a sleeve 90 in a moving contact bearing 70, wherein the sleeve 90 has two second guide elements 92, 92' and the moving contact bearing 70 has two corresponding first guide elements 72, 72'. The first guide elements 72, 72' are designed here as groove engagements, i.e., fixed structural elements. The second guide elements 92, 92' are designed as a groove in this example. The groove 92 extends over the entire length of the sleeve 90, but is limited at one end, thereby preventing the sleeve 90 and the moving contact 50 (not shown), which is connected to the sleeve 90, from slipping out of the moving contact bearing 70. List of reference symbols

[0040] 10Vacuum interrupter 20Insulating body 25Intermediate element 30Fixed contact 32Fixed contact rod 34Fixed contact disc 35Fixed contact body 40Fixed contact flange 50Moving contact 52Moving contact rod 53Third guide element 54Moving contact disc 55Moving contact body 56Longitudinal axis of the moving contact 60Moving contact flange 70Moving contact bearing 72First guide element 72'Further first guide element 80Bellows 82First bellows end 84Second bellows end 86Bellows cap 88Bellows shield 89Press-in area 90Sleeve 91Arrow for the direction of pressing in the sleeve 90 92Second guide element 92'Further second guide element 94Fourth guide element

Claims

1. Vacuum interrupter (10), having at least one insulating body (20), a fixed contact (30), a fixed-contact flange (40), a moving contact (50) having a longitudinal axis (56), a moving-contact flange (60), a moving-contact bearing (70), and a bellows (80), wherein the fixed contact (30) is arranged in a stationary manner in the fixed-contact flange (40), the moving contact (50) is movably guided in the moving-contact bearing (70), and the moving contact is movably fastened to the moving-contact flange (60) by the bellows (80), wherein the bellows (80) is fastened to the moving-contact flange (60) by a first bellows end (82), and the bellows (80) is fastened to the moving contact (50) by a second bellows end (84), wherein an increased pressure resistance of the vacuum interrupter (10) against ambient pressures over 2 bar is achieved by a sleeve (90) that is fixed on the moving contact (50), against movements along the longitudinal axis (56) of the moving contact (50), and that is configured and passed through the moving-contact bearing (70) in such a manner that the moving contact (50) has a moving-contact rod (52) and a moving-contact contact disk (54), wherein the sleeve (90) is arranged on the moving contact (50) in such a manner that the sleeve (90) extends out from the second bellows end (84) through the moving-contact bearing (70) and is extended out from the bellows (80) through the moving-contact bearing (70) on the moving-contact flange (60), and the sleeve (90) is fixed on the moving contact (50), by means of a fastening means (95), in such a manner that, during the movement of the moving contact (50), no relative movement along the longitudinal axis (56) of the moving contact (50) occurs between the moving contact (50) and the sleeve (90), characterized in that the second bellows end (84) is connected to the moving-contact rod (52) via a bellows cap (86) and the sleeve (90) is fixed in position on the moving contact (50), in the region of the second bellows end (84) and / or in the region of the bellows cap (86), by means of a press fit, latching, interlocking, soldering, welding, of a thickened portion of the moving contact not emulated by the sleeve (90).

2. Vacuum interrupter (10) according to Claim 1, characterized in that the press fit of the sleeve is effected between the second bellows end (84) and the moving contact (50), or between the bellows cap (86) and the moving-contact rod (52).

3. Vacuum interrupter (10) according to either of the preceding claims, characterized in that the moving-contact bearing (70) has at least one first guide element (72, 72') and the sleeve (90) has at least one second guide element (92, 92'), wherein the first guide element (72, 72') and the second guide element (92, 92') engage in each other in such a manner that the sleeve (90) is prevented from rotating in the moving-contact bearing (70).

4. Vacuum interrupter (10) according to Claim 3, characterized in that the first guide element (72) and the second guide element (92) engage in each other and mutually limit their movement in such a manner that the sleeve (90) does not slide out of the moving-contact bearing (70).

5. Vacuum interrupter (10) according to one of the preceding claims, characterized in that the moving-contact rod (52) has at least one third guide element (53), and the sleeve (90) has at least one fourth guide element (94), which act in combination in such a manner that rotation of the sleeve (90) on the moving-contact rod (52) is prevented.

6. Vacuum interrupter (10) according to one of the preceding claims, characterized in that the sleeve (90) is composed of a material that has a low coefficient of friction.

7. Vacuum interrupter (10) according to one of the preceding claims, characterized in that the sleeve (90) is composed of polytetrafluoroethylene or of a modification of polytetrafluoroethylene.

8. Vacuum interrupter (10) according to one of the preceding claims, characterized in that the second bellows end (84) and / or the bellows cap (86) are / is additionally provided with a bellows shield (88).

9. Vacuum interrupter (10) according to Claim 8, characterized in that the bellows shield (88) extends from the second bellows end (84) toward the moving-contact flange (60).

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