Wall bushing, and preparation method and forming device of wall bushing

Abstract

The invention provides a wall bushing, a preparation method of the wall bushing and a forming device. The wall bushing comprises a hollow insulator; the central guide rod comprises a first end part and a second end part, the central guide rod is arranged in the hollow insulator in a penetrating manner, and the central guide rod is connected with the hollow insulator; wherein in the preparation process, the central guide rod between the first end part and the second end part naturally droops relative to the end part of the central guide rod and then is shaped through aging treatment, the shaped central guide rod upwards arches and is mounted in the hollow insulator, and the upwards arching direction is opposite to the gravity direction. Through the design, the problem that the center guide rod droops can be solved.

Description

Technical Field

[0001] The present application relates to the field of power transmission technology, and in particular to a wall bushing, a preparation method of the wall bushing, and a forming device. Background Art

[0002] Since the axial dimension of the wall bushing with a voltage level above 400kV is large, and it is generally arranged horizontally or approximately horizontally in actual applications, the central guide rod used for conducting current inside it will bend and sag under the action of gravity; in order to control the distribution of the electric field, the diameter of the central guide rod is required to be small, which also causes the central guide rod to be easily deformed; in addition, in order to ensure the long-term operation reliability of the wall bushing, the support insulator in the middle of the wall bushing is generally removed, and the central guide rod is suspended in the middle of the wall bushing. These reasons make the middle of the central guide rod prone to sag. At the same time, the middle of the central guide rod is generally located in the middle of the wall bushing. In the middle of the wall bushing, since the high-potential central guide rod is the shortest distance from the grounded external wall, the discharge risk is the highest, and its insulation requirements are also high. It is generally required that the central guide rod here deviate from the central axis of the wall bushing as little as possible to reduce the risk of insulation material breakdown. The commonly used method for controlling the deformation of the central guide rod is to strengthen the cross section of the central guide rod or arrange the axis of the central guide rod eccentrically.

[0003] The first solution is to strengthen the cross-section of the center guide rod mainly by changing the material of the center guide rod to increase the stiffness of the center guide rod or by increasing the cross-sectional size of the center guide rod to improve the bending resistance of the center guide rod, so as to reduce the sagging degree of the center guide rod. However, strengthening the cross-section of the center guide rod will not eliminate the sagging in the middle, but can only reduce the degree of sagging. Moreover, the change of the cross-section of the center guide rod will inevitably lead to the change of the electric field around it, which makes its optimized design affect the design of other casings such as capacitor equalizing plates and insulating materials, making the product design process more difficult.

[0004] The second solution is an eccentric arrangement. By arranging the two ends of the center guide rod upward, the initial center guide rod axis is offset from the wall bushing axis. The offset distance is just offset with the deflection of the sagging of the middle part of the center guide rod (i.e. the amount of sagging deformation), so that the axis of the middle part of the sagging center guide rod coincides with the axis of the wall bushing after running for a period of time. However, the eccentric arrangement makes the center guide rod operate eccentrically. When its length increases due to temperature increase, the elongation of the center guide rod will be constrained by its fixed ends at both ends, causing compressive stress inside the center guide rod. The compressive stress and the eccentric arrangement are very likely to cause additional bending moment and eccentric instability. The additional bending moment makes the deformation and offset of the center guide rod more serious, and the eccentric instability may suddenly cause a huge deformation of the center guide rod, causing insulation failure. Therefore, the treatment method using the eccentric arrangement must be strictly designed in advance to release the elongation of the center guide rod caused by the temperature increase. This results in the connection part of the center guide rod and the end of the wall bushing requiring a carefully designed complex telescopic mechanism, which increases R&D investment and product production costs. Summary of the invention

[0005] In view of this, the present application provides a wall sleeve, a preparation method of the wall sleeve and a forming device, which can improve the problem of sagging of the central guide rod.

[0006] In order to solve the above problems, the first aspect of the present application provides a wall bushing, which includes: a hollow insulator; a center guide rod, including a first end and a second end, the center guide rod is inserted into the hollow insulator, and the center guide rod is connected to the hollow insulator; wherein, during the preparation process, the center guide rod between the first end and the second end naturally droops relative to the end of the center guide rod and is shaped through aging treatment, and the upward arch direction is opposite to the direction of gravity.

[0007] The above arrangement of the central guide rod arching can offset the sagging of the central guide rod under the action of gravity, thereby ultimately improving the problem of the central guide rod sagging.

[0008] In one embodiment, a first height w of the first position point on the central guide rod that naturally droops relative to the end of the central guide rod satisfies the following conditions:

[0009]

[0010] Among them, ρ is the linear density of the center guide rod, g is the acceleration of gravity, x is the distance from the first position point on the center guide rod to the first end along the first direction, L is the length between the two ends of the center guide rod, E is the Young's modulus of the center guide rod, I is the section moment of inertia of the center guide rod, and the first direction refers to the direction of the line connecting the two ends of the center guide rod.

[0011] The above arrangement allows the central guide rod to arch up to a first height after being installed in a specific direction, thereby offsetting its deflection under the action of gravity, and ensuring that after the central guide rod and the hollow insulator are installed and operated, the distance between the central guide rod and the hollow insulating tube is always equal.

[0012] In one embodiment, the hollow insulator includes: a hollow insulating tube, a center guide rod passing through the hollow insulating tube; a first end flange fixed to the first end of the center guide rod, connecting the center guide rod and the hollow insulating tube; a second end flange, sleeved on the second end of the center guide rod, connecting the center guide rod and the hollow insulating tube.

[0013] The above arrangement can ensure the stability of the connection between the central guide rod and the hollow insulator.

[0014] In one embodiment, the wall sleeve also includes: a telescopic member, located between the second end flange and the second end of the center guide rod, slidingly connecting the second end and the second end flange so that the second end can slide in a first direction relative to the second end flange, and the first direction refers to the direction of the line connecting the two ends of the center guide rod.

[0015] The above arrangement helps to release the elongation of the central guide rod caused by the increase in temperature.

[0016] In one embodiment, the central guide rod is a hollow guide rod.

[0017] The above arrangement can reduce the weight of the central guide rod, lower the cost, and also facilitate the preparation of the central guide rod.

[0018] The second aspect of the present application provides a method for preparing a wall bushing, which is used to prepare the wall bushing in any of the above-mentioned embodiments, and the method includes: fixing the first end and the second end of the center guide rod by means of a first fixing member and a second fixing member respectively; allowing the center guide rod between the first end and the second end to sag naturally; performing a shaping treatment on the center guide rod; separating the center guide rod from the first fixing member and the second fixing member, and passing the upper arch of the center guide rod through a hollow insulator and connecting it to the hollow insulator, so that the upper arch direction of the center guide rod after installation is opposite to the direction of gravity.

[0019] The above method can be used to prepare a wall bushing with a central guide rod having an upward arch shape.

[0020] In one embodiment, the step of causing the central guide rod between the first end and the second end to droop naturally comprises: controlling a lifting platform located below the central guide rod to rise until it abuts against the central guide rod.

[0021] The above method can improve the stability of sagging during the preparation of the center guide rod.

[0022] In one embodiment, the step of controlling the lifting platform below the central guide rod to rise to abut against the central guide rod comprises:

[0023] The lifting platform is controlled to rise and contact with the first position point on the central guide rod, so that the first position point is kept hanging down to a first height, wherein the first height w satisfies the following conditions:

[0024]

[0025] Among them, ρ is the linear density of the center guide rod, g is the acceleration of gravity, x is the distance from the first position point on the center guide rod to the first end along the first direction, L is the length between the two ends of the center guide rod, E is the Young's modulus of the center guide rod, I is the section moment of inertia of the center guide rod, and the first direction refers to the direction of the line connecting the two ends of the center guide rod.

[0026] Through the above method, the central guide rod can be arched up to a first height after installation, thereby offsetting its deflection under the action of gravity.

[0027] In one embodiment, the step of shaping the central guide rod comprises: heating the central guide rod to shape the central guide rod.

[0028] The heating treatment in the above method can naturally shape the bending shape of the central guide rod without complicated shape control, and the processing is simple and efficient.

[0029] In one embodiment, the central guide rod is a hollow guide rod, and the step of heating the central guide rod includes: inputting heat medium into the central guide rod; heating the heat medium, and after the temperature of the heat medium reaches a preset temperature threshold, controlling the heat medium to maintain the temperature for at least a first period of time.

[0030] The temperature and time control in the above method can achieve better shaping of the center guide rod.

[0031] According to a third aspect of the present application, there is provided a forming device for bending the central guide rod of the wall sleeve in any one of the above-mentioned embodiments, the forming device comprising: a first fixing member and a second fixing member arranged at intervals, the first fixing member being used to support and fix the first end of the central guide rod, and the second fixing member being used to support and fix the second end of the central guide rod; a supporting member being used to abut against the central guide rod after the central guide rod between the first end and the second end naturally droops; and a forming mechanism being used to form the central guide rod after the supporting member abuts against the central guide rod.

[0032] The shaping process of the central guide rod is completed by the above device.

[0033] In one embodiment, the support member includes: a lifting platform, which is arranged between the first fixing member and the second fixing member, and the lifting platform is used to rise to abut against a first position point on the naturally drooping central guide rod, so that the first position point maintains a drooping first height.

[0034] The above-mentioned arrangement of the lifting platform can ensure the stability of the drooping during the preparation of the central guide rod.

[0035] In one embodiment, the central guide rod is a hollow guide rod, and the shaping mechanism includes: a delivery pipe connected to the central guide rod, used to deliver heat medium to the central guide rod; a heater, arranged on the delivery pipe, used to heat the heat medium; a delivery pump, arranged on the delivery pipe, used to provide power for the delivery pipe to transport the heat medium.

[0036] A delivery pipe, a heater and a delivery pump are provided to achieve better shaping of the central guide rod.

[0037] In one embodiment, the shaping mechanism further comprises: a thermometer, which is arranged on the delivery pipe and is used to measure the temperature of the heat medium in the delivery pipe.

[0038] The heating temperature can be better controlled by setting a thermometer.

[0039] In one embodiment, a pulley is provided at the bottom of one of the first fixing member and the second fixing member.

[0040] The pulley structure can protect the central guide rod.

[0041] Beneficial effect: The present application installs the central guide rod in the wall bushing in a hollow insulator with an upward arch, and the upward arch direction is opposite to the direction of gravity, so that the upward arch can be used to offset the sagging of the central guide rod under the action of gravity, and ultimately the problem of sagging of the central guide rod can be improved.

[0042] The present application further provides a method for preparing a wall bushing, wherein a first end portion of a center guide rod is fixed by a first fixing member, and a second end portion of the center guide rod is fixed by a second fixing member, so that a middle portion of the center guide rod can sag naturally, and then abut the center guide rod by a supporting member, and the center guide rod is shaped by a shaping treatment, and finally the center guide rod is installed in a hollow insulator by an arch, and the direction of the arch is opposite to the direction of gravity, thereby realizing the preparation of the wall bushing, so that the arch can be used to offset the sagging of the center guide rod under the action of gravity, and the problem of sagging of the center guide rod can be improved.

[0043] The present application further provides a molding device, which fixes the first end of the center guide rod by a first fixing member and the second end of the center guide rod by a second fixing member, so that the middle part of the center guide rod can droop naturally, and then abuts the center guide rod through a support member, and further uses a molding mechanism to shape the bending of the center guide rod, thereby realizing the preparation of the center guide rod.

[0044] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0046] Figure 1 This is a structural schematic diagram of an implementation method of a wall bushing of the present application;

[0047] Figure 2 yes Figure 1 A schematic structural diagram of an embodiment of the central guide rod being finalized during the preparation process;

[0048] Figure 3 is a schematic diagram of a center guide rod constraint model of the prior art;

[0049] Figure 4 It is a schematic diagram of the bending moment of the central guide rod under the action of gravity in the prior art;

[0050] Figure 5 is a schematic diagram of the deflection of the central guide rod under the action of gravity in the prior art;

[0051] Figure 6 It is a schematic flow chart of an implementation method of a method for preparing a wall bushing of the present application;

[0052] Figure 7 yes Figure 6 A schematic diagram of an embodiment of the central guide rod in the preparation process;

[0053] Figure 8 is a flowchart of an implementation method of step S310;

[0054] Fig. 9 It is a partial structural schematic diagram of an embodiment of the molding device of the present application;

[0055] Fig.10 It is a schematic diagram of the top structure of one embodiment of the molding device of the present application. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] See also Figure 1 and Figure 2In a first aspect, the present application provides a wall bushing 10, which includes a hollow insulator 110 and a center guide rod 120; the center guide rod 120 includes a first end A and a second end B, the center guide rod 120 is inserted into the hollow insulator 110, and the center guide rod 120 is connected to the hollow insulator 110; wherein, during the preparation process, the center guide rod 120 between the first end A and the second end B naturally droops relative to the end of the center guide rod 120 and is shaped through aging treatment, and the shaped center guide rod 120 is arched and installed in the hollow insulator 110, and the arching direction S is opposite to the gravity direction G. Among them, the natural sagging of the center guide rod 120 refers to the sagging of the center guide rod 120 between the first end A and the second end B under the action of gravity when its two ends are fixed; the aging treatment of the center guide rod 120 in the natural sagging state will shape it into an arched structure; the arch installation of the center guide rod 120 refers to installing the arched center guide rod 120 in an arched upward manner, and after installation, the middle part of the center guide rod 120 is higher than the end of the center guide rod 120.

[0058] Specifically, the center guide rod 120 is used for conducting electricity, and the first end A and the second end B of the center guide rod 120 are connected to the hollow insulator 110. The center guide rod 120 is inserted into the hollow insulator 110, and the hollow insulator 110 plays an insulating role to prevent the center guide rod 120 from directly contacting the external wall. In the traditional scheme, the center guide rod is a straight guide rod during the preparation process. After being installed with the hollow insulator, under the action of gravity, the two ends of the center guide rod are supported, but the center guide rod between the two ends is not supported, so it will sag, and the farther away from the end, the more serious the sag, and the sag distance reaches the maximum value in the middle position of the center guide rod, wherein the sag amount of the above-mentioned center guide rod under the action of gravity can also be called deflection.

[0059] See also Figure 2 ( Figure 2The gravity direction G in the figure is only used as a direction indication), and in the scheme of the present application, during the preparation process of the center guide rod 120, the center guide rod 120 between the first end A and the second end B naturally droops relative to the end of the center guide rod 120 and then is shaped. That is to say, after the center guide rod 120 is prepared, the center guide rod 120 is not a straight guide rod, but a curved guide rod. When the center guide rod 120 is installed in the hollow insulator 110 with an upper arch, and the upper arch direction S is opposite to the gravity direction G, it has an upper arch in the upper arch direction S, so that the upper arch can be used to offset the sagging of the center guide rod 120 under the action of gravity, and finally the sagging problem of the center guide rod 120 can be improved. It should be noted that the above-mentioned first end A and second end B are not the two ends of the center guide rod 120, but the connecting ends of the center guide rod 120 and the hollow insulator 110, and the two ends of the center guide rod 120 mentioned in this application refer to the first end A and the second end B of the center guide rod 120, that is, as long as the center guide rod 120 between the two ends connected to the hollow insulator 110 after installation is ensured to be arched, there is no specific restriction on the shape and length of the center guide rod 120 outside the hollow insulator 110.

[0060] In one embodiment, see Figure 1 The hollow insulator 110 includes a hollow insulating tube 111, a first end flange 112 and a second end flange 113. The central guide rod 120 is inserted into the hollow insulating tube 111; the first end flange 112 is fixed to the first end A of the central guide rod 120, connecting the central guide rod 120 and the hollow insulating tube 111; the second end flange 113 is sleeved on the second end B of the central guide rod 120, connecting the central guide rod 120 and the hollow insulating tube 111.

[0061] Specifically, the central guide rod 120 passes through the hollow insulating tube 111 , and there is no contact between the central guide rod 120 and the hollow insulating tube 111 , which can improve the insulation effect of the hollow insulating tube 111 on the central guide rod 120 . The connection between the center guide rod 120 and the hollow insulating tube 111 is fixed at one end and slidable at the other end. For example, the first end A of the center guide rod 120 is fixedly connected to the first end flange 112, and the second end B of the center guide rod 120 is slidably connected to the second end flange 113, that is, they are connected by a sleeve. The advantage of this is that the second end B of the center guide rod 120 can slide in the first direction X (the first direction X refers to the direction of the line connecting the two ends of the center guide rod 120), because under the action of gravity, the drooping of the center guide rod 120 will drive the end of the center guide rod 120 to move in the first direction X. The end of the center guide rod 120 can be displaced by sliding to release the force of the center guide rod 120 on the first end flange 112 and the second end flange 113 in the first direction X, thereby ensuring the connection stability between the center guide rod 120 and the hollow insulator 110.

[0062] In some other embodiments, the center guide rod and the hollow insulating tube may not be connected by using end flanges, but an insulating member may be used to connect the hollow insulating tube and the center guide rod, and the insulating member and the hollow insulating tube may be integrally formed.

[0063] In one embodiment, see Figure 1 The wall sleeve 10 also includes a telescopic member 130, which is located between the second end flange 113 and the second end B of the center guide rod 120, and slidably connects the second end B and the second end flange 113 so that the second end B can slide in the first direction X relative to the second end flange 113.

[0064] Specifically, by setting a telescopic member 130 between the second end B of the center guide rod 120 and the second end flange 113, the second end B can slide relative to the second end flange 113 in the first direction X to release the force of the center guide rod 120 on the first end flange 112 and the second end flange 113, thereby further improving the connection stability between the center guide rod 120 and the hollow insulator 110.

[0065] Of course, in some other embodiments, the telescopic member may not be provided between the second end flange and the second end of the center guide rod, and sliding between the second end flange and the second end of the center guide rod can be achieved by applying lubricating oil between the second end flange and the second end of the center guide rod.

[0066] In one embodiment, see Figure 2, the central guide rod 120 is a hollow guide rod. The hollow guide rod can reduce the overall weight of the central guide rod 120 without much loss in cross-sectional rigidity, thereby reducing the amount of sagging, and using less material and lowering the cost; at the same time, the hollow guide rod facilitates the preparation of the bending of the central guide rod 120, and the specific content can be referred to the following embodiments. Of course, in some other embodiments, the central guide rod can also be a solid guide rod, and this application does not make specific restrictions on this.

[0067] First, based on the estimation of the first deflection of the central guide rod under the action of gravity in the prior art, refer to Figure 3 The central guide rod 150 in the prior art (labeled differently from the central guide rod 120 of the present application) also has a first end A and a second end B, wherein the first end A is fixedly constrained and the second end B is slidably constrained. The slidably constrained central guide rod 150 only allows the central guide rod 150 to slide in the horizontal direction, but does not allow the central guide rod 150 to slide in the vertical direction or rotate in any direction. Figure 4 , the center guide rod 150 is represented by the axis where the centroid of its cross section is located. Along the first direction X in the figure (the direction of the line connecting the first end A and the second end B), according to the center guide rod 150 under the action of gravity, a bending moment M will be generated inside the center guide rod 150, which makes the cross section of the center guide rod 150 half compressed and half tensile, and the bending moment M of the tension of the lower part of the center guide rod 150 is drawn below the center guide rod 150, and the bending moment M of the tension of the upper part is drawn above the center guide rod 150. It can be seen that the bending moment M of the center guide rod 150 is a quadratic curve, and the bending moment M of the first end A and the second end B of the center guide rod 150 is The bending moment M in the middle of the central guide rod 150 is Wherein, ρ is the linear density of the central guide rod 150 , which is the product of the area of ​​the positive cross section of the central guide rod 150 and the material density of the central guide rod 150 , g is the acceleration of gravity, and L is the length between the two ends of the central guide rod 150 .

[0068] Furthermore, under the action of gravity, the deformation of the central guide rod 150 is still small compared to its length, which can be regarded as a small deformation situation. Since the central guide rod 150 is generally made of alloy material, it has good elasticity. It can be considered that it still meets the plane section assumption and the linear elastic assumption when it is subjected to the bending moment M, so the following approximate equation can be used:

[0069]

[0070] Wherein, κ is the curvature of the center guide rod 150 after deformation, y is the deflection of any position point on the center guide rod 150 relative to the line connecting the two ends of the center guide rod 150 in the gravity direction G, y′ is the first-order derivative of the first deflection y, that is, the cross-sectional rotation angle in radians, and its value is much less than 1 under the premise of small deformation, y (2) is the second derivative of the first deflection y (see Figure 5, a coordinate system is established with the first end A as the origin, the first direction X as the horizontal axis, i.e., the x-axis, and the gravity direction G as the vertical axis, i.e., the y-axis, wherein the first end A points to the second end B as the positive direction of the horizontal axis, and the gravity direction G points to the positive direction of the vertical axis). In the above formula, the bending moment M drawn below the central guide rod 150 is positive, I is the section inertia moment, and E is the Young's modulus of the central guide rod 150.

[0071] The cross section of the hollow central guide rod 150 is annular. For the annular cross section, the section inertia moment I can be determined according to the following formula:

[0072]

[0073] Wherein, D is the outer diameter of the central guide rod 150 , d is the inner diameter of the central guide rod 150 , and the inner diameter d is greater than 0.

[0074] According to the bending moment M of the first end A, the bending moment M of the second end B, the bending moment M of the middle portion of the central guide rod 150 and the approximate formula of the curvature κ, it can be obtained:

[0075]

[0076] The above formula can be integrated to obtain the first deflection y under gravity:

[0077]

[0078] Secondly, based on the evaluation of the second deflection caused by creep under long-term energized operation of the central guide rod 150, during the flow process, the central guide rod 150 generates heat due to its own resistance, so the central guide rod 150 will creep due to long-term heat and stress during operation, generating an additional second deflection. Currently, the material commonly used for the central guide rod 150 is aluminum alloy. The creep of aluminum alloy will first experience a rapid development in the first stage, in which the creep is very small and often negligible; followed by a gradually stable second stage in which the creep strain rate is approximately constant. For 6 series aluminum alloys and 7 series aluminum alloys, the second stage will occur at a temperature above 145°C, and according to GB / T 4109-2022, the average operating temperature of the center guide rod 150 should not exceed 130°C, and the maximum temperature should not exceed 140°C, so the aluminum alloy will not produce second stage creep; the third stage is the destruction stage, but it only occurs at high temperatures (higher than 0.3 times the melting point, for example, 0.3 times the melting point of aluminum alloy is between 168°C and 198°C, which is higher than the operating temperature of the center guide rod 150), so the center guide rod 150 will not produce third stage creep.

[0079] Furthermore, the material commonly used for the center guide rod 150 is generally a 6-series aluminum alloy. According to the creep formula ε below 145°C for a similar 7-series aluminum alloy, c =Aσ nt m The formula for estimating the creep of 6 series aluminum alloys is obtained by fitting the experimental data: c =9.4852×10 -18 σ -5.65 t 0.47344 Among them, ε c is the creep strain, σ is the uniaxial stress of the material, and t is the duration of high temperature. It should be noted that under the action of gravity, the center guide rod 150 has shear stress in addition to axial stress, but the deformation caused by the shear stress of the thin-walled rod with L>8D is much lower than the deformation caused by the axial stress, so the creep caused by shear force is ignored in this application. The service life of a general wall bushing is 30 years, i.e. 262800h. For a center guide rod with L=10000mm, D=120mm, and d=100mm, its maximum axial stress is 10.5MPa, and the corresponding elastic strain is 1.3×10 -4 (The density and elastic modulus of aluminum alloy are taken as 2700kg / m 3 , 79000MPa), located at the outer edge of the fixed ends, according to the formula, the creep strain within its service life is 2.05×10 -9 , compared with the axial strain caused by gravity and temperature expansion and contraction, it can be ignored. Therefore, for the center guide rod 150, the second deflection generated during use can be ignored.

[0080] In summary, the first deflection y of the central guide rod 150 caused by gravity is much larger than the second deflection caused by creep under long-term energized operation, so the second deflection is ignored, and the deflection of the central guide rod 150 is the first deflection y.

[0081] Based on the above evaluation of the deflection of the central guide rod 150 in the prior art, in one embodiment, refer to Figure 2 After the central guide rod 120 droops naturally under the action of gravity, the heights of various positions on the central guide rod 120 between the first end A and the second end B will decrease to varying degrees, wherein there is a position point with the largest drop in height, i.e., the position point with the lowest height on the central guide rod 120 after the natural droop, and this position point is defined as the first position point. The first height w of the first position point on the central guide rod 120 relative to the natural droop of the end of the central guide rod 120 satisfies the following conditions:

[0082]

[0083] Among them, ρ is the linear density of the center guide rod 120, which is equal to the product of the volume density and the cross-sectional area of ​​the center guide rod 120, g is the gravitational acceleration, x is the distance from the first position point on the center guide rod 120 to the first end A along the first direction X, L is the length between the two ends of the center guide rod 120, E is the Young's modulus of the center guide rod 120, I is the section moment of inertia of the center guide rod 120, and the first direction X refers to the direction of the line connecting the two ends of the center guide rod 120.

[0084] The center guide rod 120 of the present application is formed into a naturally drooping curved shape during the preparation process, and the first drooping height w is basically consistent with the first deflection y of the center guide rod 150 under the action of gravity in the prior art. Therefore, when the center guide rod 120 is installed in the hollow insulator 110 with an upper arch, the upper arch can be used to offset the drooping of the center guide rod 120 under the action of gravity, and finally the problem of the sagging of the center guide rod 120 can be avoided. After the center guide rod 120 is installed and operated, its shape is approximately straight, and not curved, thus ensuring that the distance between the center guide rod 120 and the wall of the hollow insulating tube 111 is almost equal everywhere, avoiding the risk of breakdown.

[0085] See also Figure 6 and Figure 7 In a second aspect, the present application provides a method for preparing a wall bushing 10, which is used to prepare the wall bushing 10 of any one of the above embodiments, and the method comprises:

[0086] S100 : Fixing the first end A and the second end B of the central guide rod 120 by means of the first fixing member 210 and the second fixing member 220 respectively.

[0087] Specifically, both ends of the center guide rod 120 are fixed by fixing parts, which may be clamps, etc. In order to ensure the effect of subsequent installation of the center guide rod 120 in the wall sleeve 10, during preparation, the distance between the first fixing part 210 and the second fixing part 220 after fixing the center guide rod 120 is the distance between the first end A and the second end B of the center guide rod 120 in the above-mentioned embodiment.

[0088] S200: Allow the central guide rod 120 between the first end portion A and the second end portion B to droop naturally.

[0089] Specifically, since both ends of the central guide rod 120 are fixed by fixing members, the central guide rod 120 between the first end A and the second end B lacks middle support and naturally droops under the action of gravity.

[0090] S300: performing shaping processing on the central guide rod 120.

[0091] Specifically, the shaping process is to maintain the curved shape of the central guide rod 120 rather than the central guide rod 120 returning to a straight shape after the fixing member is separated, so that the curved shape of the central guide rod 120 can be maintained.

[0092] S400: Separate the central guide rod 120 from the first fixing member 210 and the second fixing member 220, and arch the central guide rod 120 through the hollow insulator 110 to connect with the hollow insulator 110, so that the arch direction S of the central guide rod 120 after installation is opposite to the gravity direction G.

[0093] Specifically, it can be combined Figure 1 and Figure 7 After the center guide rod 120 is separated from the first fixing member 210 and the second fixing member 220, when the center guide rod 120 is installed in the hollow insulator 110, the arch direction S of the center guide rod 120 needs to be kept opposite to the gravity direction G, so that the arched part of the center guide rod 120 can gradually sag under the action of gravity during subsequent operation and return to a straight line, so that the distance between the center guide rod 120 and the wall of the hollow insulating tube 111 is equal everywhere, avoiding the risk of breakdown, thereby improving the sagging problem of the center guide rod 120. It can be understood that if the center guide rod 120 is not installed in an arched manner, especially when the arched direction S is the same as the gravity direction G, the sagging problem of the center guide rod 120 will be more serious. Therefore, it is quite critical whether the arched direction S is opposite to the gravity direction G during installation.

[0094] In one embodiment, see Figure 7 The above step S200 includes:

[0095] S210 : controlling a lifting platform (not shown) located below the central guide rod 120 to rise until it contacts the central guide rod 120 .

[0096] Specifically, since the sagging central guide rod 120 needs to be subjected to aging treatment and finalization later, in order to prevent the central guide rod 120 from further elongating and sagging due to heat during the aging treatment, a support device is provided below the central guide rod 120 to just abut against the central guide rod 120 that naturally sags under the action of gravity. Selecting a lifting platform as the support device can ensure the stability of the sagging of the central guide rod 120 during the preparation process, and can also adjust the rising distance, so as to facilitate adjustment according to the first sagging height w of the central guide rod 120, thereby improving the versatility of the equipment.

[0097] In one embodiment, see Figure 7 The above step S210 specifically includes: controlling the lifting platform to rise and abut against the first position point on the central guide rod 120, so that the first position point remains drooped to a first height w.

[0098] Specifically, the first position point is the position point with the lowest height on the center guide rod 120 after natural drooping. At the same time, this step does not limit the number of lifting platforms. That is to say, one lifting platform can be used to abut the first position point of the center guide rod 120, or multiple lifting platforms can be used simultaneously to abut other positions on the center guide rod 120, as long as each position point maintains the height of natural drooping.

[0099] Among them, the first height w satisfies the following conditions:

[0100]

[0101] Among them, ρ is the linear density of the central guide rod 120, g is the acceleration of gravity, x is the distance from the first position point on the central guide rod 120 to the first end A along the first direction X, L is the length between the two ends of the central guide rod 120, E is the Young's modulus of the central guide rod 120 at the stable operating temperature (because the maximum temperature of the central guide rod 120 during operation does not exceed 140°C, the reduction of the elastic modulus is not serious, and the Young's modulus at room temperature can be approximately used), I is the sectional moment of inertia of the central guide rod 120, and the first direction X refers to the direction of the line connecting the two ends of the central guide rod 120.

[0102] Specifically, Figure 7 In the process, a lifting platform (not shown) is used to rise to a first position point abutting against the center guide rod 120, so that the first position point keeps a first downward height w in the subsequent preparation process, and then when the center guide rod 120 is installed after the arch is raised, the first height w of the arch of the center guide rod 120 and the first deflection y of the center guide rod 120 under the action of gravity can offset each other, so that the center guide rod 120 is in a straight line under the action of gravity after installation and operation.

[0103] In one application scenario, the first height of the first position point naturally drooping is Substituting the above parameters into the calculation, the value is 8.4mm.

[0104] In one embodiment, see Figure 8 The above step S300 includes:

[0105] S310: The central guide rod 120 is subjected to a heating treatment so as to shape the central guide rod 120 .

[0106] Specifically, the material of the central guide rod 120 is metal or alloy, so the central guide rod 120 can be shaped by aging treatment, wherein the central guide rod 120 can be shaped in a drooping shape by heating.

[0107] In one embodiment, in combination Figure 1 and Figure 8, the central guide rod 120 is a hollow guide rod, and the above step S310 includes:

[0108] S311 : Inputting heat medium into the central guide rod 120 .

[0109] Specifically, the central guide rod 120 is a hollow guide rod, and a heat medium can be introduced into the central guide rod 120 to heat the entire central guide rod 120 . The heat medium can be a high-boiling point oil that is non-corrosive to the central guide rod 120 .

[0110] S312: heating the heat medium, and after the temperature of the heat medium reaches a preset temperature threshold, controlling the heat medium to maintain the temperature for at least a first period of time.

[0111] Specifically, aging treatment usually requires a certain temperature to be maintained for a certain time to complete the creep of the material, thereby achieving a shaping effect. Heating is a common method of aging treatment. Therefore, it is necessary to control the heat medium to maintain a first time length after being heated to a preset temperature threshold (the preset temperature threshold is the temperature required for the creep of the material of the central guide rod 120). The first time length is the time length required for the creep of the material of the central guide rod 120. The preset temperature threshold and the first time length may be different for different materials, and are not specifically limited here.

[0112] In one application scenario, the material of the center guide rod 120 is aluminum alloy, and 180°C is a temperature suitable for aging treatment of aluminum alloy. At this temperature, it can be approximately considered that the creep deformation of each position point on the center guide rod 120 is linearly related to its stress. In actual use, the center guide rod 120 will produce elastic deformation under the action of gravity, and its elastic deformation is also proportional to its stress. This shows that after aging treatment, basically no excessive internal stress will be generated due to deformation coordination problems, and the pre-bent shape of the center guide rod 120 is also a deformation caused by its own gravity. During actual operation, the axis of the center guide rod 120 will coincide with the ideal axis height.

[0113] The creep strain of the central guide rod 120 at each position reaches the deadweight strain ε m =σ m / E The first time required t h Should satisfy: m / E=1.22×10 -6 σ m 0.9252 t h 0.3161 , it is approximately considered that σ m ≈σ m 0.9252 ,but Among them, σ mis the stress at a certain position of the aluminum alloy under its own weight, E is the elastic modulus of the aluminum alloy, and E is 79000MPa, so as to obtain the first time length t h =1639s=27min.

[0114] See also Fig. 9 and Fig.10 In a third aspect, the present application provides a forming device 20 for bending the central guide rod 120 of the wall sleeve 10 in any of the above-mentioned embodiments. The forming device 20 comprises: a first fixing member 210 and a second fixing member 220, a support member 230 and a shaping mechanism 240, which are arranged at intervals. The first fixing member 210 is used to support and fix the first end A of the central guide rod 120, and the second fixing member 220 is used to support and fix the second end B of the central guide rod 120; the support member 230 is used to abut against the central guide rod 120 after the central guide rod 120 between the first end A and the second end B droops naturally; the shaping mechanism 240 is used to shape the central guide rod 120 after the support member 230 abuts against the central guide rod 120.

[0115] Specifically, the first fixing member 210 and the second fixing member 220 fix the two ends of the center guide rod 120, and the center guide rod 120 between the first end A and the second end B droops naturally. The support member 230 abuts against the drooping center guide rod 120, and then the shaping mechanism 240 is used to shape the drooping shape of the center guide rod 120 so that the center guide rod 120 can have a curved shape after preparation. In this way, when the center guide rod 120 is installed in an arched manner, the drooping of the center guide rod 120 under the action of gravity can be offset to a certain extent, thereby improving the drooping problem of the center guide rod 120.

[0116] In one embodiment, see Fig. 9 The support member 230 includes a lifting platform, which is arranged between the first fixing member 210 and the second fixing member 220. The lifting platform is used to rise to a first position point on the naturally drooping central guide rod 120 to keep the first position point drooping at a first height w.

[0117] Specifically, the lifting platform can ensure the stability of the sagging of the center guide rod 120 during its preparation. At the same time, the lifting platform can adjust the rising distance, which is convenient for adjustment according to the first height w of the sagging of the center guide rod 120, thereby improving the versatility of the equipment.

[0118] Of course, in some other implementations, the drooping central guide rod may also be butted against by supporting members such as a jack or an overhead crane.

[0119] In one embodiment, see Fig. 9The central guide rod 120 is a hollow guide rod, and the shaping mechanism 240 includes: a delivery pipe 241, a heater 242 and a delivery pump 243. The delivery pipe 241 is connected to the central guide rod 120 and is used to deliver heat medium to the central guide rod 120; the heater 242 is arranged on the delivery pipe 241 and is used to heat the heat medium; the delivery pump 243 is arranged on the delivery pipe 241 and is used to provide power for the delivery pipe 241 to deliver the heat medium.

[0120] Specifically, the delivery pipe 241 is connected to the two ends of the central guide rod 120, the delivery pipe 241 is filled with heat medium, the delivery pump 243 provides the delivery power of the heat medium, so that the heat medium is thermally circulated in the delivery pipe 241 and the central guide rod 120, and the heater 242 provides heat so that the heat medium can be continuously heated. Therefore, the above-mentioned shaping mechanism 240 can ensure that the central guide rod 120 completes the bending shaping in a continuously heated environment through the thermal circulation of the heat medium when the central guide rod 120 maintains a stable naturally drooping state.

[0121] Of course, in some other embodiments, heat forming can also be performed by electrically heating the central guide rod.

[0122] In one embodiment, see Fig.10 The shaping mechanism 240 further includes a thermometer 244, which is disposed on the delivery pipe 241 and is used to measure the temperature of the heat medium in the delivery pipe 241. By monitoring the temperature of the heat medium in the delivery pipe 241 through the thermometer 244, it can better ensure that the central guide rod 120 completes the bending shaping at a preset temperature.

[0123] In one embodiment, a pulley 250 is disposed at the bottom of one of the first fixing member 210 and the second fixing member 220 .

[0124] Specifically, the first fixing member 210 and the second fixing member 220 may be a clamp, etc., and the clamp may be a tool such as a vise. A pulley 250 is provided at the bottom of one of the first fixing member 210 and the second fixing member 220, and the pulley 250 can slide, so as to ensure that when the center guide rod 120 is heated, the first fixing member 210 and the second fixing member 220 are subjected to the force in the first direction X generated by the expansion and contraction of the center guide rod 120 due to heat, the force can be released through the pulley 250. On the one hand, this can simulate the situation where the center guide rod 120 is installed on the hollow insulator 110, so that the preparation of the center guide rod 120 is closer to the application scene. On the other hand, the release of the force by the pulley 250 can prevent the first fixing member 210 and the second fixing member 220 from damaging the center guide rod 120. A pad 260 can be provided at the bottom of the first fixing member 210 or the second fixing member 220 without the pulley 250 to achieve the relative position fixation of the fixing member to the ground.

[0125] In a specific application scenario, see Fig. 9 and Fig.10 The present application provides a method for preparing a central guide rod 120, wherein the central guide rod 120 is made of aluminum alloy, and the method is as follows:

[0126] S01: Draw a line on the ground, and set the pad vise and the sliding vise (the first fixing member 210 is the pad vise, and the second fixing member 220 is the sliding vise) on the same straight line, wherein the pad vise is fixed to the ground, and the sliding vise can slide relative to the ground, and the sliding direction is limited to the first direction X.

[0127] S02: Insert the cast iron pipe 270 at both ends of the center guide rod 120. The port of the cast iron pipe 270 located inside the center guide rod 120 should reach or slightly exceed the edge of the anchoring section of the center guide rod 120. After the installation is completed, fill the sealing ring in the gap between the center guide rod 120 and the cast iron pipe 270. The cast iron pipe 270 is inserted at both ends of the center guide rod 120 to facilitate the subsequent connection with the oil hose (i.e., the delivery pipe 241).

[0128] S03: Fix both ends of the central guide rod 120 with a vise, and align the clamping position of the vise with the first end A and the second end B of the central guide rod 120 as much as possible.

[0129] S04: The central guide rod 120 droops naturally under the action of gravity, and a lifting platform (i.e., the support member 230) is placed below the middle of the central guide rod 120, and the lifting platform is controlled to rise to abut against the lower edge of the central guide rod 120, so that the middle of the central guide rod 120 remains drooped at a first height w. The first height w can be calculated according to the specific parameters of the central guide rod 120 actually used.

[0130] S05: Heat and deliver non-corrosive high-boiling-point oil (i.e., heat medium) through a liquid-storable temperature-controlled heater (i.e., heater 242) and a high-temperature water pump (i.e., delivery pump 243), control the heating temperature at about 180°C, and introduce it into the cast iron pipe 270 on one side of the center guide rod 120 through an oil delivery hose and output it back to the temperature-controlled heater from the cast iron pipe 270 on the other side, observe the reading of the thermometer 244, and start timing when the reading of the thermometer 244 stabilizes at about 180°C.

[0131] S06: After 30 minutes, turn off the temperature control heater and the high-temperature water pump, and let the central guide rod 120 and the hot oil slowly cool to room temperature. After reaching room temperature, collect the oil and store it properly, and measure whether the sagging distance of the central guide rod 120 meets the standard. If not, continue to repeat the above steps S01 to S05. It can be understood that the heating time of this step is set to 30 minutes, which exceeds the theoretical calculation value, and can ensure the shaping effect of the central guide rod 120. In some other embodiments, the heating time can also be set to 27 minutes, 28 minutes, 31 minutes, etc., as long as the shaping treatment of the central guide rod can be achieved, and no specific restrictions are made here.

[0132] S07: Clean the interior of the central guide rod 120 at room temperature, and dry it naturally or at a relatively low temperature, so as to obtain the central guide rod 120 having a curved shape.

[0133] By means of the above preparation method, when the center guide rod 120 is installed in the hollow insulator 110 by an upward arch, the middle section of the center guide rod 120 will gradually drop to a height substantially the same as the heights of the two ends under the action of gravity, thereby improving the sagging problem of the center guide rod 120.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural contradiction, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A wall bushing, characterized in that: The wall bushing comprises: Hollow insulators; A central guide rod, comprising a first end and a second end, wherein the central guide rod is passed through the hollow insulator and connected to the hollow insulator; Among them, during the preparation process, the center guide rod between the first end and the second end naturally droops relative to the end of the center guide rod and is shaped through aging treatment. The shaped center guide rod is installed in the hollow insulator with an upward arch direction opposite to the direction of gravity.

2. The wall bushing according to claim 1, characterized in that: A first height w of the first position point on the central guide rod that naturally droops relative to the end of the central guide rod satisfies the following conditions: Among them, ρ is the linear density of the central guide rod, g is the acceleration of gravity, x is the distance from the first position point on the central guide rod to the first end along the first direction, L is the length between the two ends of the central guide rod, E is the Young's modulus of the central guide rod, I is the section moment of inertia of the central guide rod, and the first direction refers to the direction of the line connecting the two ends of the central guide rod.

3. The wall bushing according to claim 1, characterized in that: The hollow insulator comprises: A hollow insulating tube, wherein the central guide rod is passed through the hollow insulating tube; A first end flange, fixed to the first end of the central guide rod, connecting the central guide rod and the hollow insulating tube; The second end flange is sleeved on the second end of the central guide rod and connects the central guide rod and the hollow insulating tube.

4. The wall bushing according to claim 3, characterized in that: The wall bushing also includes: The telescopic member is located between the second end flange and the second end of the center guide rod, and slidably connects the second end and the second end flange so that the second end can slide in a first direction relative to the second end flange, and the first direction refers to the direction of the line connecting the two ends of the center guide rod.

5. The wall bushing according to claim 1, characterized in that: The central guide rod is a hollow guide rod.

6. A method for preparing a wall bushing, used for preparing the wall bushing according to any one of claims 1 to 5, characterized in that: The method comprises: Fixing the first end and the second end of the central guide rod by a first fixing member and a second fixing member respectively; Allowing the central guide rod between the first end and the second end to droop naturally; Performing shaping treatment on the central guide rod; The central guide rod is separated from the first fixing member and the second fixing member, and the upper arch of the central guide rod is passed through the hollow insulator and connected to the hollow insulator, so that the upper arch direction of the central guide rod after installation is opposite to the direction of gravity.

7. The method according to claim 6, characterized in that The step of causing the central guide rod between the first end and the second end to droop naturally comprises: The lifting platform located below the central guide rod is controlled to rise until it abuts against the central guide rod.

8. The method according to claim 7, characterized in that The step of controlling the lifting platform below the central guide rod to rise to abut against the central guide rod comprises: The lifting platform is controlled to rise and abut against a first position point on the central guide rod, so that the first position point is kept hanging down to a first height, wherein the first height w satisfies the following conditions: Among them, ρ is the linear density of the central guide rod, g is the acceleration of gravity, x is the distance from the first position point on the central guide rod to the first end along the first direction, L is the length between the two ends of the central guide rod, E is the Young's modulus of the central guide rod, I is the section moment of inertia of the central guide rod, and the first direction refers to the direction of the line connecting the two ends of the central guide rod.

9. The method according to claim 6, characterized in that The step of shaping the central guide rod comprises: The central guide rod is subjected to a heat treatment so as to be shaped.

10. The method according to claim 9, characterized in that The central guide rod is a hollow guide rod, and the step of heating the central guide rod comprises: Inputting heat medium into the central guide rod; The heat medium is heated, and after the temperature of the heat medium reaches a preset temperature threshold, the heat medium is controlled to maintain the temperature for at least a first period of time.

11. A forming device for bending the central guide rod of the wall bushing according to any one of claims 1 to 5, characterized in that: The forming device comprises: A first fixing member and a second fixing member are arranged at intervals, wherein the first fixing member is used to support and fix the first end of the central guide rod, and the second fixing member is used to support and fix the second end of the central guide rod; A support member, used to abut against the central guide rod after the central guide rod between the first end and the second end sags naturally; The shaping mechanism is used for shaping the central guide rod after the support member abuts against the central guide rod.

12. The molding device according to claim 11, characterized in that: The support member comprises: A lifting platform is arranged between the first fixing member and the second fixing member, and is used for rising to abut against a first position point on the naturally drooping central guide rod, so that the first position point maintains a drooping first height.

13. The molding device according to claim 11, characterized in that: The central guide rod is a hollow guide rod, and the shaping mechanism comprises: A delivery pipe, connected to the central guide rod, for delivering heat medium to the central guide rod; A heater, disposed on the delivery pipe, for heating the heat medium; The delivery pump is arranged on the delivery pipe and is used to provide power for the delivery pipe to transport the heat medium.

14. The forming device according to claim 13, characterized in that: The shaping mechanism also includes: A thermometer is arranged on the delivery pipe and is used to measure the temperature of the heat medium in the delivery pipe.

15. The forming device according to claim 11, characterized in that: A pulley is provided at the bottom of one of the first fixing member and the second fixing member.

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