A method for estimating the amount of bushing expansion

Abstract

This invention relates to a method for estimating the expansion amount of a bushing, comprising the following steps: S1, measuring the outer diameter D of the bushing and the inner diameter d1 of the bushing; S2, unfolding the cylindrical bushing into a rectangle to obtain the total length L of the bushing after expansion of the center layer. 中 S3, the expansion amount δ of the diameter centerline layer after rolling the expanded rectangle into a new bushing in the diametrical direction. 胀 S4. Calculate the expansion δ in the inner diameter direction. 内 ; Calculate the expansion δ in the outer diameter direction 外 S5, according to δ 内 Set the preset value C of the inner diameter of the bushing 内 According to δ 外 Set the preset value C of the bushing outer diameter 外 This invention provides a method for estimating the expansion amount of a bushing. This method can obtain the expansion amount of the inner diameter and the outer diameter separately, so that when designing the bushing, the clearance between the bushing and the shaft can be set according to the expansion amount of the inner diameter of the bushing, and the clearance between the bushing and the valve body can be set according to the expansion amount of the outer diameter of the bushing.

Description

Technical Field

[0001] This invention relates to a prediction method, specifically a method for predicting the expansion of a bushing. Background Technology

[0002] The butterfly plate of a metal hard-seal butterfly valve is installed in the diameter direction of the pipeline. Inside the cylindrical passage of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, with a rotation angle between 0° and 90°. When rotated to 90°, the valve is in the fully open state.

[0003] Metal hard-seal butterfly valves behave differently at different temperatures. Metal hard-seal butterfly valves with the same parameters operate smoothly under normal temperature conditions, but under high temperature conditions, the valve opening and closing torque becomes very large or even jams. Through analysis, it was found that the expansion of the bushing at high temperature makes the gap between the valve stem and the bushing, and between the bushing and the valve body too small. Therefore, it is necessary to leave an appropriate gap between the valve stem and the bushing, and between the bushing and the valve body.

[0004] The current formula for calculating thermal expansion is δ=L*α*△T, where L refers to the length of the object. ΔT refers to the coefficient of thermal expansion, while ΔT refers to the temperature difference. However, the expansion required by the bushing is the expansion in the diameter direction of the bushing, which cannot be directly calculated using the thermal expansion formula. Furthermore, there is currently no reasonable way to estimate the expansion of the bushing, and relying on experience can easily lead to inappropriate clearances between the valve stem and the bushing, and between the bushing and the valve body. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method for predicting the expansion of the bushing.

[0006] To achieve the above objectives, the present invention provides the following technical solution, comprising the following steps: S1. The outer diameter of the measuring sleeve is D, and the inner diameter of the measuring sleeve is... The coefficient of thermal expansion is set to The temperature difference is set to ΔT, and the diameter of the center layer of the bushing is... ; S2. Unfold the cylindrical bushing into a rectangle, and the total length of the bushing after expansion of the central layer is: ; S3. Roll the expanded rectangle to the diameter of the new bushing. Expansion of the midline layer in the diametrical direction The bushing thickness is Expansion in the thickness direction ; S4. Calculate the expansion in the inner diameter direction. ; Calculate the expansion in the outer diameter direction ; S5, according to Set the preset value of the inner diameter of the bushing. ,according to Set the preset value of the bushing outer diameter .

[0007] The present invention is further configured such that step S2 includes: the length of the centerline layer of the bushing is... The expansion amount of the midline layer is obtained through the expansion amount calculation formula. The total length of the midline layer after expansion is .

[0008] The present invention is further configured such that step S3 includes: calculating according to the following formula and ; ; .

[0009] The present invention is further configured such that step S4 includes: calculating according to the following formula and Expansion in the inner diameter direction under a temperature difference of ΔT Expansion in the outer diameter direction at temperature ΔT .

[0010] The present invention is further configured to include a valve stem, a bushing, and a valve body, wherein the valve stem is rotatably disposed within the valve body, the bushing is disposed between the valve body and the valve stem, and the gap between the valve stem and the bushing serves as... The gap between the bushing and the valve body is used as .

[0011] Beneficial effects: By unfolding the bushing into a rectangular shape and then using the formula for thermal expansion, the expansion of the bushing's center layer in the diametrical direction can be calculated. However, if this value is directly used as a preset value, the actual inner diameter expansion and outer diameter expansion of the bushing will still have a large difference from the preset value. Therefore, the thickness of the bushing is considered in the theoretical derivation, and it is improved into a more specific estimation method for the inner diameter and outer diameter expansion of the bushing, so that the estimation results are closer to the actual situation. The expansion of the inner diameter and outer diameter are calculated separately, so that when designing the bushing, the clearance between the bushing and the shaft can be set according to the inner diameter expansion of the bushing, and the clearance between the bushing and the valve body can be set according to the outer diameter expansion of the bushing. Attached Figure Description

[0012] Figure 1 This is a structural block diagram of the entire invention;

[0013] Figure 2 This is a side view of the bushing of the present invention;

[0014] Figure 3The present invention is unfolded into a rectangular bushing and a side view and a front view.

[0015] Figure 4 This is a partial sectional view of the bushing, valve body, and valve stem of the present invention. Detailed Implementation

[0016] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0018] like Figure 1-4 As shown, this invention discloses a method for predicting the expansion amount of a bushing, comprising the following steps: S1. The outer diameter of the measuring sleeve 2 is D, and the inner diameter of the measuring sleeve 2 is... The coefficient of thermal expansion is set to The temperature difference is set to ΔT, and the diameter of the inner layer of bushing 2 is... ; S2. Unfold the cylindrical bushing 2 into a rectangle, and the total length of the expanded inner layer of bushing 2 is: ; S3. Roll the expanded rectangle to the diameter of the new bushing 2. Expansion of the midline layer in the diametrical direction The thickness of bushing 2 is Expansion in the thickness direction ; S4. Calculate the expansion in the inner diameter direction. ; Calculate the expansion in the outer diameter direction ; S5, according to Set the preset value of the inner diameter of bushing 2 ,according to Set the preset value of the outer diameter of bushing 2 .

[0019] Step S2 also includes: the length of the middle layer of the bushing 2 is The expansion amount of the midline layer is obtained through the expansion amount calculation formula. The total length of the midline layer after expansion is .

[0020] Step S3 also includes: calculating according to the following formula and ; ; .

[0021] Step S4 also includes: calculating according to the following formula and Expansion in the inner diameter direction under a temperature difference of ΔT Expansion in the outer diameter direction at temperature ΔT .

[0022] The valve body includes a valve stem 3, a bushing 2, and a valve body 1. The valve stem 3 is rotatably mounted inside the valve body 1, and the bushing 2 is positioned between the valve body 1 and the valve stem 3. The gap between the valve stem 3 and the bushing 2 serves as... The gap between the bushing 2 and the valve body 1 is used as .

[0023] Example 1: Specifying the parameters, D=120mm, =100mm, α=13.2*10 -6 △T=300mm; Substitute In the middle, get ; Substitute In the middle, get = ;

[0024] In existing technologies In the middle, get ;

[0025] Right now arrive The range between 0.396 and 0.4356 mm serves as a reference range for the preset value between bushing 2 and valve stem 3. The range between 0.4356 and 0.4752 mm serves as a reference range for the preset value between the bushing 2 and the valve body 1.

[0026] Example 2: Specificifying the parameters, D=160, =140mm, α=5*10 -6 △T=400mm, centerline layer diameter d=150mm;

[0027] Substitute In the middle, get ;

[0028] Substitute In the middle, get =0.32;

[0029] In existing technologies In the middle, get ;

[0030] Right now arrive The range between 0.28-0.3mm serves as a reference range for the preset value between bushing 2 and valve stem 3. The range between 0.3 and 0.32 mm serves as a reference range for the preset value between the bushing 2 and the valve body 1.

Claims

1. A method for predicting the expansion amount of a bushing, characterized in that, Includes the following steps: S1. The outer diameter of the measuring sleeve is D, and the inner diameter of the measuring sleeve is... The coefficient of thermal expansion is set to The temperature difference is set to ΔT, and the diameter of the center layer of the bushing is... ; S2. Unfold the cylindrical bushing into a rectangle, and calculate the total length of the bushing's center layer after expansion using the thermal expansion formula. The length of the centerline layer of the bushing is The expansion amount of the midline layer is obtained through the expansion amount calculation formula. The total length of the midline layer after expansion is ; S3. Roll the expanded rectangle into a new bushing. The diameter of the expanded new bushing... Expansion of the midline layer in the diametrical direction The bushing thickness is The amount of expansion of the bushing in the thickness direction ; S4. Calculate the expansion in the inner diameter direction. ; Calculate the expansion in the outer diameter direction ; S5, according to Set the preset value of the inner diameter of the bushing. ,according to Set the preset value of the bushing outer diameter. The valve with the bushing includes a valve stem, a bushing, and a valve body. The valve stem is rotatably mounted within the valve body, and the bushing is positioned between the valve body and the valve stem. The gap between the valve stem and the bushing serves as... The gap between the bushing and the valve body is used as .

2. The method for estimating the expansion amount of a bushing according to claim 1, characterized in that, Step S3 also includes: calculating according to the following formula and ; ; .

3. The method for estimating the expansion amount of a bushing according to claim 2, characterized in that, Step S4 also includes: calculating according to the following formula and Expansion in the inner diameter direction under a temperature difference of ΔT Expansion in the outer diameter direction at temperature ΔT .

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