Water seal pressing plate with conical counter bore structure

Abstract

The utility model provides a water seal pressing plate with a conical counter bore structure, which comprises a pressing plate, a water seal rubber and a water seal base plate, and a plurality of round holes are respectively arranged among the pressing plate, the water seal rubber and the water seal base plate and are locked by bolts and nuts. The round hole in the pressing plate is a conical counter bore, and the bolt is a conical countersunk bolt. The conical counter bore is matched with the conical countersunk bolt, so that the contact area between the conical counter bore and the conical countersunk bolt is increased, the contact pressure is optimized, and the connection reliability and the mechanical strength performance are ensured; the installation hole of the water seal pressing plate of the conical counter bore structure and the conical countersunk bolt are assembled to form a tight binding face, so that the installation hole, the conical countersunk bolt and the water seal pressing plate are completely solidified into a whole, and under the working conditions of a high water head and an ultrahigh water head, the water seal bearing performance and the tearing resistance are more effectively clamped and supported; the mounting hole of the water seal pressing plate of the conical countersink structure is assembled with the conical countersunk bolt to form a tight binding surface, so that water accumulation or impurity silting in the operation process is prevented, electrochemical corrosion is reduced, and safe use of the bolt and the pressing plate is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to water conservancy and hydropower engineering technical field, concretely relates to a water seal pressing plate of conical counterbore structure. BACKGROUND

[0002] In water conservancy projects, the pressing plate is used as a clamping and supporting part of the rubber water seal, and it helps the rubber water seal to operate under high water head and ensures the sliding and tearing resistance.

[0003] The current water seal pressing plate has been using a cylindrical counterbore structure, which is matched with a cylindrical conical countersunk bolt. The contact between the cylindrical conical countersunk bolt and the pressing plate is a circular working surface. Influenced by the small contact area and the low hardness of the pressing plate surface, the contact stress between the two increases significantly when they operate under high water head, which can easily lead to the crushing failure of the contact surface of the pressing plate or the penetration failure of the pressing plate, and induce the functional sealing failure of the rubber water seal.

[0004] The machining geometry of the cylindrical counterbore structure of the current water seal pressing plate is large, which increases the processing amount of the pressing plate material, increases the manufacturing cost, and causes great damage to the base material of the pressing plate. When the pressing plate is under load, the rigidity is challenged, which leads to excessive deformation of the pressing plate under high water head pressure, and easily induces the structural sealing failure and functional failure of the rubber water seal.

[0005] The assembly gap between the cylindrical counterbore structure of the current water seal pressing plate and the cylindrical conical countersunk bolt is prone to electrochemical corrosion due to the accumulation of water or debris during operation, which affects the safe use of the bolt and the pressing plate and causes difficulty in maintenance and disassembly.

[0006] The current water seal pressing plate uses a bolt group to cooperatively bear the load for clamping and supporting the rubber water seal. Due to the small contact surface between the pressing plate and the bolt and the small installation friction resistance, the bearing capacity of a single bolt fluctuates greatly, which makes it difficult to control the cooperativity of the bolt group and causes uneven bearing. Under high water head sealing pressure operation, the pressing plate is prone to local stress concentration and large deformation failure, or the rubber water seal is over-borne and relaxed, which induces the functional sealing failure of the rubber water seal. INVENTION CONTENTS

[0007] The main purpose of the utility model is to provide a water seal pressing plate with a conical counterbore structure, which is expected to effectively solve the problems in the background technology.

[0008] To achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0009] A water seal pressing plate with a conical counterbore structure, comprising a pressing plate, a water seal rubber, and a water seal backing plate, wherein a plurality of round holes are provided between the pressing plate, the water seal rubber, and the water seal backing plate, and are locked by bolts and nuts; the round holes on the pressing plate are conical counterbores, and the bolts are conical countersunk bolts.

[0010] In addition, the utility model also can adopt or adopt the following technical scheme in combination:

[0011] As a preferred technical scheme of the utility model: the angle of the conical counter bore is 90°.

[0012] As a preferred technical scheme of the utility model: the angle of the conical counter bore is 120°.

[0013] As a preferred technical scheme of the utility model: the external profile of the conical countersunk bolt is consistent with the internal profile of the conical counter bore.

[0014] As a preferred technical scheme of the utility model: the pressing plate is made of high-strength structural steel material.

[0015] The utility model provides a kind of water seal pressing plate of conical counter bore structure, with following beneficial effects: by providing conical counter bore and conical countersunk bolt cooperation, the contact area between the two can be significantly increased, so that the contact pressure between bolt head and pressing plate is effectively improved, ensuring the reliability and mechanical strength performance of connection;The mounting hole of the water seal pressing plate of conical counter bore structure and conical countersunk bolt assembly form tight fitting surface, so that conical countersunk bolt, pressing plate and water seal bottom plate are completely consolidated integral, under high water head, ultra-high water head condition, water seal bearing and tear resistance are more effectively clamped and supported;The mounting hole of the water seal pressing plate of conical counter bore structure and conical countersunk bolt assembly form tight fitting surface, prevent water or sundries from being jammed during operation, reduce the occurrence of electrochemical corrosion, ensure the safe use of bolt and pressing plate. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is the schematic diagram of the water seal pressing plate of conical counter bore structure provided by the utility model;

[0017] Figure 2 It is the sectional view of the water seal pressing plate of conical counter bore structure provided by the utility model;

[0018] Figure 3 It is the enlarged view of conical counter bore;

[0019] Figure 4 It is the schematic diagram when conical counter bore is 90°;

[0020] Figure 5 It is the schematic diagram when conical counter bore is 120°;

[0021] In the drawing: 1-pressing plate;2-conical countersunk bolt;3-water seal rubber;4-nut;5-water seal backing plate;11-conical counter bore. DETAILED DESCRIPTION

[0022] The utility model will be further described in detail with reference to the drawings and specific embodiments.

[0023] As Figures 1-5 shown, a water seal pressure plate of conical counterbore structure, comprising a pressure plate 1, a water seal rubber 3, a water seal backing plate 5, a plurality of round holes are respectively arranged between the pressure plate 1, the water seal rubber 3 and the water seal backing plate 5 and locked by bolts and nuts, the round hole on the pressure plate 1 is a conical counterbore 11, and the bolt is a conical countersunk bolt 2.

[0024] The angle of the conical counterbore is 90 degrees.

[0025] The angle of the conical counterbore is 120 degrees.

[0026] The outer profile of the conical countersunk bolt 2 is consistent with the inner profile of the conical counterbore 11.

[0027] The pressure plate 1 is made of high-strength structural steel material.

[0028] Specifically, the water seal pressure plate of conical counterbore structure is implemented in the following manner:

[0029] In the actual installation process, first, the water seal rubber 3 is laid on the interface that needs to be water-stopped, then the pressure plate 1 is placed above the water seal rubber 3, so that the through hole is aligned with the screw hole position on the water seal rubber 3, then the conical countersunk bolt 2 is inserted into the conical counterbore 11 on the pressure plate 1, and the pressure plate 1 and the water seal rubber 3 are clamped and fixed by the nut 4, due to the close fit of the conical bolt head and the conical counterbore 11 structure of the pressure plate 1, the conical countersunk bolt 2, the pressure plate 1 and the water seal backing plate 5 are completely integrated, under high water head and super high water head conditions, the water seal bearing and tear resistance are more effectively clamped and supported, and the durability and reliability of the water seal operation are ensured.

[0030] Specifically, the determination of the angle of the conical counterbore is implemented in the following manner:

[0031] The water seal pressure plate of conical counterbore structure adopts taper optimization design, the specific taper condition of the installation hole of the water seal pressure plate of conical counterbore structure is between 60 degrees and 90 degrees, the water seal bearing and tear resistance are more effectively clamped and supported, and the specific analysis steps are as follows:

[0032] S1: the specific taper condition of the installation hole of the water seal pressure plate of conical counterbore structure is started from 90 degrees with a step of 5 degrees, and a finite element model is established based on the stress characteristics of the water seal pressure plate and the bolt;

[0033] S2: based on the hydrostatic formula, the water pressure is represented as:

[0034] P = ρgh (1)

[0035] In the above formula, p is the fluid density, g is the local gravity acceleration, and h is the water depth.

[0036] S3: Under the action of water pressure, the contact stress between the pressing plate and the conical countersunk bolt is a shear stress τ, which is expressed as:

[0037]

[0038] In the above formula, F is the water pressure on the pressing plate, and A is the contact area between the pressing plate and the conical countersunk bolt at the tapered groove.

[0039] S4: The contact area between the pressing plate and the conical countersunk bolt at the tapered groove is expressed as:

[0040] A = πr 2 tan(θ) (3)

[0041] In the above formula, r is the radius of the counterbore.

[0042] S5: Based on the basic formula of mechanics, the relationship between the opening angle of the tapered groove and the water pressure is derived:

[0043] F = S · P (4)

[0044] Substitute the contact area A:

[0045]

[0046] S6: Based on the national standard GB or the empirical formula, set the maximum shear stress τ that the countersunk bolt can withstand under high water head: max An empirical formula is provided for calculating the ultimate shear stress value:

[0047] τ max = 0.6 · σ d (6)

[0048] In formula (6), σ d is the maximum allowable tensile strength that the bolt material can withstand.

[0049] S7: To ensure design safety, a safety factor SF is proposed to ensure that the shear stress on the bolt remains within a safe range under various working conditions:

[0050]

[0051] In the above formula, SF is 1.25 for a more conservative pressing plate actual working condition, and SF is 1.11 for a more aggressive pressing plate actual working condition. In fact, the size of the safety factor SF depends on the safety requirements of the actual operation scene of the pressing plate. For pressing plates that work in vibration, impact, and other fatigue working conditions for a long time, the SF value is usually 2 or 3.

[0052] S8: According to the taper optimization design calculation method of the water seal plate mounting hole of the conical counterbore structure, the taper optimization and the working standard of the plate conical counterbore mounting hole structure are analyzed and compared:

[0053] S81: If the shear stress does not exceed the maximum allowable shear stress of the material, the design requirements are preliminarily met:

[0054] τ≤τ max (8)

[0055] S82: Calculate and compare the safety factor. If the safety factor SF meets the working condition design standard, it is considered that the selected θ satisfies the safety allowance condition:

[0056] SF≥SF 工况 (9)

[0057] In the above formula, the value of SF working condition is set through the standard described in S7.

[0058] S83: Analyze the working state of the plate-bolt system. If the conditions τ≤τ max and SF≥SF 工况 are met, the design meets the safe operation condition; otherwise, the taper of the conical counterbore is continuously optimized with a step size of 5°, and the calculation and verification are re-performed according to steps S1-S8 until the conical counterbore angle is reduced and the design is optimized.

[0059] S84: For special purposes of ultra-high water head, the opening taper θ of the water seal plate mounting hole of the conical counterbore structure is adjusted according to the water pressure size within the range of 60°-90° according to the need of load bearing and rubber water seal clamping and protection. When the water pressure is large, a smaller taper angle provides stronger water pressure bearing and rubber water seal clamping and protection performance, thereby enhancing the anti-deformation ability of the plate and ensuring the durability and reliability of the water seal operation.

[0060] Considering the specifications and economy of the conical counterbore bolt standard parts, based on the above-mentioned calculation method, among the 90° and 120° specifications, the opening taper θ of the plate conical counterbore structure is selected. The plate conical counterbore mounting through-hole structure takes θ value of 120°, aiming to significantly reduce the material cutting amount, thereby optimizing the material use efficiency and reducing the manufacturing cost. Taking θ value of 90°, the effective contact area between the bolt head and the plate increases, and the mutual contact stress distribution tends to be uniform, avoiding local stress concentration and material crushing failure phenomenon, effectively improving the durability and reliability of the plate under high and ultra-high water head working conditions.

[0061] Under the condition of conventional water head, considering the specifications and economy of the standard parts of conical countersunk head bolt, the taper of the installation hole of the water seal pressure plate with conical countersunk hole structure is selected from the two specifications of 90° and 120°, the water seal pressure plate with conical countersunk hole structure is checked by using the taper optimization design calculation method, so as to ensure that the water seal bearing and tear resistance performance are more effectively clamped and supported, and the specific analysis steps are as follows:

[0062] S1: The installation hole of the water seal pressure plate with conical countersunk hole structure is selected according to the taper of 120° specification, and based on the stress characteristics of the water seal pressure plate and the bolt, a finite element model is established.

[0063] S2: Based on the formula of fluid statics, the water pressure is represented as:

[0064] P = ρgh (10)

[0065] In the formula, ρ is the fluid density, g is the local gravity acceleration, and h is the water depth.

[0066] S3: Under the action of water pressure, the contact stress between the pressure plate and the conical countersunk bolt is a shear stress τ, which is represented as:

[0067]

[0068] In the formula, F is the water pressure on the pressure plate, and A is the contact area of the pressure plate and the conical countersunk bolt at the tapered groove.

[0069] S4: The contact area of the pressure plate and the conical countersunk bolt at the tapered groove is represented as:

[0070] A = πr 2 tan (θ) (12)

[0071] In the formula, r is the radius of the countersunk hole.

[0072] S5: Based on the basic formula of mechanics, the relationship between the opening angle of the tapered groove and the water pressure is derived:

[0073] F = S·P (13)

[0074] Substitute the contact area A:

[0075]

[0076] S6: Based on the national standard GB or the empirical formula, the maximum shear stress τ that the countersunk bolt can withstand under high water head is set max , an empirical formula is provided for calculating the limit shear stress value:

[0077] τ max = 0.6·σ d (15)

[0078] In the above formula, σ d is the maximum allowable tensile strength that the bolt material can withstand.

[0079] S7: To ensure design safety, a safety factor SF is proposed to ensure that the shear stress on the bolt can be maintained within a safe range under various working conditions:

[0080]

[0081] In the above formula, SF is 1.25 for the more conservative actual working condition of the pressing plate, and SF is 1.11 for the more aggressive actual working condition of the pressing plate. In fact, the size of the safety factor SF depends on the safety requirements of the actual operation scene of the pressing plate. For pressing plates that work in fatigue conditions such as vibration and impact for a long time, the value of SF is usually 2 or 3.

[0082] S8: According to the taper optimization design calculation method of the water seal pressing plate mounting hole with a conical counterbore structure, the taper optimization is analyzed and compared with the working standard of the pressing plate conical counterbore mounting hole structure:

[0083] S81: If the shear stress does not exceed the maximum allowable shear stress of the material, the design requirements are initially met:

[0084] τ ≤ τ max (17)

[0085] S82: Calculate and compare the safety factor. If the safety factor SF meets the working condition design standard, it is considered that the selected θ satisfies the safety allowance condition:

[0086] SF ≥ SF 工况 (18)

[0087] In the above formula, the value of SF is set by the standard described in S7.

[0088] S83: Analyze the working state of the pressing plate-bolt system. If the conditions τ ≤ τ max and SP ≥ SF 工况 are met, the design meets the safe operation condition; otherwise, the water seal pressing plate mounting hole with a conical counterbore structure is specified as a taper of 90°, the taper of the conical counterbore is further optimized, and the steps S1-S8 are recalculated and verified until the angle of the conical counterbore is reduced.

[0089] Further, through finite element analysis, the bolt-plate finite element model of the component is solved, the stress distribution, stress concentration and displacement field distribution of the plate and the bolt under the action of high water head are solved, the τ value is set as the pressure load, and the deformation of the bolt-plate system under the working condition is obtained, the local overload or crushing risk is analyzed and compared, the taper θ of the water seal plate mounting hole of the conical counterbore structure is checked and optimized and adjusted, the deformation of the bolt-plate system is controlled within the allowable range, and the reliability of long-term operation of the system is ensured. The above specific embodiments are used to explain and illustrate the utility model, which is only a preferred embodiment of the utility model, but not a limitation on the utility model, and any modification, equivalent replacement, improvement, etc. of the utility model within the spirit and protection scope of the claims of the utility model all fall within the protection scope of the utility model.

Claims

1. A water seal pressing plate of conical counter bore structure, comprising a pressing plate (1), a water seal rubber (3), a water seal backing plate (5), a plurality of round holes are respectively arranged between the pressing plate (1), the water seal rubber (3) and the water seal backing plate (5) and locked by bolts and nuts. characterized in that The round hole on the pressing plate (1) is a conical counter bore (11), and the bolt is a conical countersunk bolt (2).

2. The conical counterbore water seal pressure plate of claim 1, wherein: The angle of the conical counter bore (11) is 90°.

3. The conical counterbore water seal pressure plate of claim 1, wherein: The angle of the conical counter bore (11) is 120°.

4. The conical counterbore water seal pressure plate of claim 1, wherein: The outer profile of the conical countersunk bolt (2) is consistent with the inner profile of the conical counter bore (11).

5. The conical counterbore water seal pressure plate of claim 1, wherein: The pressing plate (1) is made of high-strength structural steel material.

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