A waterproof and breathable structure for balancing internal and external air pressure

Abstract

The present invention relates to the field of actuator technology, and discloses a waterproof and breathable structure for balancing internal and external air pressure, including an upper shell and a lower shell, wherein the lower shell is made of plastic material, an inner cavity is formed between the upper shell and the lower shell, an air hole communicating with the outside is opened on the lower shell, a metal insert is embedded in the lower shell, an air passage communicating with the inner cavity is formed between the metal insert and the lower shell, and the air passage communicates with the air hole. The present invention can achieve balancing of the large air pressure difference generated by the alternating high and low temperatures in the inner cavity, prevent the protective shell from being deformed or damaged under the long-term pressure difference between the inside and the outside, and has a certain ability to resist the infiltration of external liquids.

Description

Technical Field

[0001] The present invention relates to the technical field of actuators, and in particular to a waterproof and breathable structure for balancing internal and external air pressures. Background Art

[0002] The actuator is an essential and important part of the automatic control system. Its function is to receive the control signal sent by the controller, change the size of the controlled medium, and thus maintain the controlled variable at the required value or within a certain range. The protective shell on the actuator is usually made of plastic. When the inner cavity of the actuator alternates between high and low temperatures and generates a large air pressure difference, the protective shell is easily deformed or damaged under the pressure difference between the inside and outside for a long time, and the existing actuator has poor ability to resist the immersion of external liquids.

[0003] In order to solve the above technical problems, the existing actuator usually needs to cover the vent hole of the sealing cover with a layer of waterproof and breathable material through connection technology. This waterproof and breathable material allows gas to pass smoothly to achieve the effect of ventilation, while preventing liquid from entering the cavity to achieve the effect of waterproofing. However, the manufacturing process of the breathable material itself is complicated, and the material price and manufacturing cost are high.

[0004] Common connection technologies used for breathable materials include hot melt welding and adhesive bonding. Hot melt welding is to use hot melt welding equipment to melt the connection base material to the melting point and penetrate into the breathable material under a certain pressure. After the base material solidifies, it is fixed with the breathable material. There are certain requirements for the melting point of the base material and the ability to penetrate the breathable material. For base materials with high melting points and poor permeability, it is difficult to meet the connection strength under high pressure conditions, and the connection parts are prone to tearing and leakage.

[0005] Adhesive bonding is to pre-fabricate adhesive with adhesive on the breathable material, and apply pressure to the breathable material to connect the breathable material and the substrate. However, the adhesive is prone to aging in the process of alternating high and low temperatures for a long time, and the connection between the breathable material and the substrate is prone to peeling and delamination under external pressure (such as immersion in liquid), which greatly shortens the service life and reduces reliability.

[0006] Although the use of breathable waterproof materials can make the actuator waterproof and breathable, the breathable waterproof materials are inconvenient to use. They need to be connected and fixed on the actuator casing using the above two methods, which is cumbersome to operate. After installing the breathable waterproof materials, it is difficult to meet the requirements under high pressure and high temperature conditions. The connection parts are prone to tearing, peeling and delamination, resulting in a short service life and low reliability. Summary of the invention

[0007] The present invention is intended to provide a waterproof and breathable structure for balancing the internal and external air pressure, so as to achieve balancing the large air pressure difference generated when the inner cavity changes between high and low temperatures, prevent the protective shell from being deformed or damaged under the long-term pressure difference between the inside and outside, and have a certain ability to resist the infiltration of external liquids.

[0008] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a waterproof and breathable structure for balancing internal and external air pressure, comprising an upper shell and a lower shell, the lower shell is made of plastic material, an inner cavity is formed between the upper shell and the lower shell, an air hole communicating with the outside is opened on the lower shell, a metal insert is embedded in the lower shell, a breathable channel communicating with the inner cavity is formed between the metal insert and the lower shell, and the breathable channel is communicated with the air hole.

[0009] The principles and advantages of this solution are:

[0010] In the present invention, the lower shell is made of plastic material. By embedding a metal insert in the lower shell, the difference in thermal expansion coefficients between plastic and metal is utilized so that the sizes of the two cannot completely match each other during thermal expansion and contraction, thereby forming a microchannel.

[0011] At high temperatures, the expansion volume of plastic is greater than that of metal, thereby expanding the gap between the plastic lower shell and the metal insert. The gas inside the sealed inner cavity expands at high temperatures, and the air pressure in the inner cavity is greater than the external pressure. The gas overflows from the inside to the outside until the internal and external pressures are balanced. However, when the internal pressure of the inner cavity is greater than the external pressure, the external liquid cannot penetrate into the sealed cavity.

[0012] When subjected to low-temperature impact, the volume of plastic shrinkage is greater than that of metal. At this time, the gap between the plastic lower shell and the metal insert is reduced, and the gas inside the sealed inner cavity shrinks at low temperature. The internal air pressure is lower than the external pressure. The gas molecules are much smaller than the liquid molecules, and the gas can also enter from the outside to the inside until the internal and external pressures are balanced; and the liquid molecules will enter the air permeable channel at a certain speed under the external pressure. The channel becomes narrower at low temperatures, and the liquid is subject to huge friction resistance in the channel, so that the purpose of balancing the external liquid pressure can be achieved within a certain length of the air permeable channel, thereby resisting the large-scale infiltration of external liquid.

[0013] The present invention is applied to the inner cavity of the actuator, and is capable of balancing the air pressure, having the function of being waterproof and breathable, so as to achieve balancing the large air pressure difference generated when the inner cavity changes alternately between high and low temperatures, thereby preventing the protective shell (i.e., the upper shell and the lower shell in this solution) from being deformed or damaged under the long-term pressure difference between the inside and the outside, and having a certain ability to resist the infiltration of external liquids.

[0014] This waterproof and breathable structure has stronger resistance to liquid pressure impact, longer life, more stability and higher reliability than the breathable material solution. In addition, the metal insert material in this solution is easy to obtain, the manufacturing method is simple, the processing cycle is short and the cost is low.

[0015] Preferably, as an improvement, both ends of the air permeable channel are connected to the inner cavity, and the air permeable channel passes through the air permeable hole.

[0016] Beneficial effect: Both ends of the ventilation channel are connected to the inner cavity, which can speed up the ventilation speed and increase the ventilation area, resulting in better ventilation effect.

[0017] Preferably, as an improvement, both ends of the metal insert extend into the inner cavity.

[0018] Beneficial effect: The parts of the two ends of the metal insert extending into the inner cavity are arranged in this way to facilitate installation and fixation during the production and processing process. The parts of the metal insert extending into the inner cavity are also easier to neatly store during the production process and to package and fix several metal inserts through fixing parts, so as to facilitate transportation to the next link for processing or sales.

[0019] Preferably, as an improvement, a positioning hole is provided on the metal insert, and the positioning hole is communicated with the air vent.

[0020] Beneficial effects: The positioning hole is used to communicate with the vent hole and form an external entrance and exit with the outside world. In addition, the positioning hole is convenient for positioning processing as a positioning hole in the process of producing the metal insert, so that the processed metal insert is more in line with the standard.

[0021] Preferably, as an improvement, the corrugated sections of the metal insert are distributed on both sides of the positioning hole.

[0022] Beneficial effect: The metal inserts on both sides of the positioning hole are corrugated sections, thereby forming bidirectional corrugated sections, so that the metal inserts on both sides of the positioning hole have a corrugated structure, which can further increase the friction resistance and channel length of liquid immersion and improve the waterproof effect.

[0023] Preferably, as an improvement, the metal insert has a corrugated section, and the corrugated section of the metal insert is coated in the lower shell.

[0024] Beneficial effects: The corrugated metal insert can make the air permeable channel match its shape, so that the air permeable channel can form a tortuous channel, and the corrugated structure of the metal insert can effectively increase the friction resistance and channel length of liquid immersion, and the waterproof effect is better.

[0025] Preferably, as an improvement, the metal insert includes two fixed plates, a horizontal plate and two corrugated plates, the corrugated section on the metal insert is located on the two corrugated plates, the two ends of the horizontal plate are respectively connected to the two corrugated plates, the other ends of the two corrugated plates are respectively connected to the two fixed plates, the ends of the two fixed plates extend into the inner cavity, and the positioning holes are located on the horizontal plate.

[0026] Beneficial effect: The metal insert in this solution consists of three parts. The horizontal sheet serves to connect the two corrugated sheets, and the positioning hole is located on the horizontal sheet. Compared with processing the positioning hole on the corrugated sheet, this solution is more convenient to operate when processing the positioning hole because the horizontal plane is a planar structure.

[0027] The two fixing plates are used to extend into the inner cavity, and the portion extending into the inner cavity does not need to be configured as a corrugated structure, thereby reducing the manufacturing cost and facilitating installation and fixation during production and processing.

[0028] Preferably, as an improvement, the fixed sheet, the corrugated sheet and the horizontal sheet are integrally formed.

[0029] Beneficial effect: In this way, the metal insert can be produced more quickly as a whole, and the production efficiency is high.

[0030] Preferably, as an improvement, the portion of the metal insert embedded in the lower shell is in contact with the inner wall of the air permeable channel.

[0031] Beneficial effect: This solution can form a narrower channel between the metal insert and the side wall of the air permeable channel, thereby achieving a better waterproof effect.

[0032] Preferably, as an improvement, the lower shell is injection molded, and a metal insert is embedded in the process of injection molding of the lower shell.

[0033] Beneficial effect: The solution is simple in that the metal insert is embedded in the lower shell by injection molding, and the connection and matching structure between the metal insert and the lower shell is more stable, and the problem of tearing, peeling and delamination at the connection part in the prior art is not likely to occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a partial longitudinal cross-sectional schematic diagram of an embodiment of a waterproof and breathable structure for balancing internal and external air pressures of the present invention.

[0035] Figure 2 The present invention is a partial structural diagram of a waterproof and breathable structure for balancing internal and external air pressure. DETAILED DESCRIPTION

[0036] The following is further described in detail through specific implementation methods:

[0037] The reference numerals in the drawings of the specification include: an upper shell 1 , a corrugated section 2 , a lower shell 3 , a lower shell dust-proof protrusion 31 , a fixing plate 4 , a positioning hole 5 , a vent hole 6 , and a horizontal plate 7 .

[0038] The embodiment is basically as shown in the attached Figure 1 and Figure 2 As shown: a waterproof and breathable structure for balancing internal and external air pressure, applied to the outer shell of the actuator, the waterproof and breathable structure includes an upper shell 1 and a lower shell 3 of the actuator. In this embodiment, the upper shell 1 and the lower shell 3 are both made of plastic material, and an inner cavity is formed between the upper shell 1 and the lower shell 3.

[0039] The bottom of the lower shell 3 is provided with a lower shell dust-proof protrusion 31 protruding downward, and the lower shell 3 is provided with a vent hole 6 communicating with the outside. In this embodiment, the vent hole 6 is located on the lower shell dust-proof protrusion 31. A metal insert is embedded in the lower shell 3, and a vent channel is formed between the metal insert and the lower shell 3, and the vent channel is communicated with the inner cavity and the vent hole 6.

[0040] In this embodiment, the metal insert and the lower shell 3 are molded by injection molding to embed the metal insert into the lower shell 3. In actual operation, the lower shell 3 is molded by injection molding, and the metal insert is embedded in the process of injection molding of the lower shell 3. Specifically: during the injection molding of the lower shell 3, part of the lower shell material is first injected into the mold, and then the metal insert is placed in the mold and then the remaining lower shell material is injected, so that the metal insert is embedded in the lower shell 3.

[0041] In this embodiment, both ends of the air permeable channel are connected to the inner cavity, and the middle part of the air permeable channel passes through the air hole 6, so that the air permeable channel has a two-way air permeable structure, which can increase the air permeability area and speed.

[0042] Both ends of the metal insert extend into the inner cavity, and a positioning hole 5 is provided in the center of the metal insert, which communicates with the air hole 6. The metal insert has a corrugated section 2, that is, the metal insert has a corrugated structure, so that the formed air permeable channel has a tortuous structure, which can effectively increase the friction resistance and channel length of liquid immersion and improve the waterproof effect.

[0043] The air permeable channel is a channel formed by injection molding between the metal insert and the lower shell 3, and its shape matches the shape of the metal insert, and also has a corrugated section. In this embodiment, the corrugated section 2 of the metal insert is coated in the lower shell 3 and distributed on both sides of the positioning hole 5. Specifically: In this embodiment, the metal insert includes two fixed sheets 4, a horizontal sheet 7 and two corrugated sheets, and the fixed sheet 4, the horizontal sheet 7 and the corrugated sheet are integrally formed.

[0044] The two fixing plates 4 are located at the left and right ends of the metal insert, the horizontal plate 7 is located in the center of the metal insert, and the positioning hole 5 is processed on the horizontal plate 7, and the two corrugated plates are parts of the corrugated sections 2 on the metal insert. The two fixing plates 4 are vertically arranged and perpendicular to the horizontal plate 7, one end of the two fixing plates 4 is respectively connected to the two corrugated plates, and the other end of the fixing plates 4 extends into the inner cavity.

[0045] In this embodiment, the two corrugated sheets are respectively located on both sides of the horizontal sheet 7, and the two ends of the metal insert extend out of the lower shell 3 and are located in the inner cavity. Compared with one end of the metal insert extending into the inner cavity, this scheme can not only increase the area of ​​the air permeability channel, but also facilitate installation and fixation during the production process. During the production process, the two ends of the metal insert extending out of the inner cavity can be used for fixation, which is more convenient to operate.

[0046] In this embodiment, the part of the metal insert embedded in the lower shell 3 fits with the inner wall of the air permeable channel, so that the metal insert and the plastic lower shell 3 are tightly fitted to form a narrow and tortuous air permeable channel, and the air permeable channel is connected to the air permeable holes 6 on the lower shell 3, together forming a waterproof and breathable structure.

[0047] The specific implementation process is as follows:

[0048] When the actuator is in a high temperature environment, according to the principle that the expansion volume of plastic is greater than the expansion volume of metal, the gap between the plastic lower shell 3 and the metal insert will gradually expand, that is, the air permeable channel becomes larger at this time, and the gas inside the sealed inner cavity will gradually expand at high temperature. When the air pressure in the inner cavity is greater than the external pressure, the gas will overflow from the inner cavity and be discharged through the air permeable channel until the internal and external pressures are balanced. However, when the internal pressure of the inner cavity is greater than the external pressure, the external liquid cannot penetrate into the sealed cavity, thereby playing a waterproof role.

[0049] When the actuator is subjected to low temperature impact, according to the principle that the volume of plastic shrinkage is greater than that of metal shrinkage, the gap between the plastic lower shell 3 and the metal insert is reduced, that is, the width of the air permeable channel is very narrow at this time, and the gas inside the sealed inner cavity shrinks at low temperature. The internal air pressure is lower than the external pressure, and the gas molecules are much smaller than the liquid molecules. The gas can also enter the inner cavity from the outside through the air permeable channel until the internal and external pressures are balanced.

[0050] Under external pressure, liquid molecules will enter the air permeable channel at a certain speed. However, since the air permeable channel becomes narrower at low temperatures and there are corrugated metal inserts in the air permeable channel, the length of the air permeable channel is relatively long, and the liquid will encounter huge friction resistance in the air permeable channel. Therefore, the purpose of balancing the external liquid pressure can be achieved within a certain length of the air permeable channel, thereby resisting the large-scale infiltration of external liquid.

[0051] The present invention is applied to the inner cavity of the actuator, and is capable of balancing the air pressure, having the function of being waterproof and breathable, so as to achieve balancing the large air pressure difference generated when the inner cavity changes alternately between high and low temperatures, thereby preventing the protective shell (i.e., the upper shell 1 and the lower shell 3 in this solution) from being deformed or damaged under the long-term pressure difference between the inside and the outside, and having a certain ability to resist the infiltration of external liquids.

[0052] In this embodiment, the metal insert is embedded into the lower shell 3 by injection molding, without the need for hot melt welding and adhesive bonding as in the prior art. The embedding method in this embodiment will not cause tearing, peeling and delamination at the connection parts as in the prior art, and the structure is more stable.

[0053] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A waterproof and breathable structure for balancing internal and external air pressure, comprising an upper shell and a lower shell, wherein the lower shell is made of plastic material, and an inner cavity is formed between the upper shell and the lower shell, characterized in that: The lower shell is provided with an air hole communicating with the outside, a metal insert is embedded in the lower shell, an air passage communicating with the inner cavity is formed between the metal insert and the lower shell, and the air passage is communicated with the air hole; the metal insert has a corrugated section, and the corrugated section of the metal insert is covered in the lower shell; When in a high temperature environment, the air permeable passage between the lower shell and the metal insert becomes larger, the gas in the inner cavity expands under high temperature, the air pressure in the inner cavity is greater than the external pressure, and the gas overflows from the inner cavity and is discharged through the air permeable passage until the internal and external pressures are balanced; when the internal pressure of the inner cavity is greater than the external pressure, external liquid cannot penetrate into the inner cavity; When subjected to low temperature impact, the air permeable passage between the lower shell and the metal insert becomes narrower, the gas in the inner cavity contracts at low temperature, the air pressure in the inner cavity is lower than the external pressure, and the gas enters the inner cavity from the outside through the air permeable passage until the internal and external pressures are balanced; the air permeable passage becomes narrower at low temperature, and the external liquid is subjected to friction resistance in the air permeable passage, thereby preventing the external liquid from infiltrating into the inner cavity in large quantities.

2. A waterproof and breathable structure for balancing internal and external air pressure according to claim 1, characterized in that: Both ends of the air permeable channel are communicated with the inner cavity, and the air permeable channel passes through the air permeable hole.

3. A waterproof and breathable structure for balancing internal and external air pressure according to claim 2, characterized in that: Both ends of the metal insert extend into the inner cavity.

4. A waterproof and breathable structure for balancing internal and external air pressure according to any one of claims 1 to 3, characterized in that: The metal insert is provided with a positioning hole, which is communicated with the vent hole.

5. A waterproof and breathable structure for balancing internal and external air pressure according to claim 4, characterized in that: The corrugated sections of the metal insert are distributed on both sides of the positioning hole.

6. A waterproof and breathable structure for balancing internal and external air pressure according to claim 1, characterized in that: The metal insert includes two fixed plates, a horizontal plate and two corrugated plates. The corrugated section on the metal insert is located on the two corrugated plates. The two ends of the horizontal plate are respectively connected to the two corrugated plates. The other ends of the two corrugated plates are respectively connected to the two fixed plates. The ends of the two fixed plates extend into the inner cavity. The positioning holes are located on the horizontal plate.

7. A waterproof and breathable structure for balancing internal and external air pressure according to claim 6, characterized in that: The fixed sheet, the corrugated sheet and the horizontal sheet are integrally formed.

8. A waterproof and breathable structure for balancing internal and external air pressure according to claim 1, characterized in that: The portion of the metal insert embedded in the lower shell is in contact with the inner wall of the air permeable channel.

9. A waterproof and breathable structure for balancing internal and external air pressure according to claim 1, characterized in that: The lower shell is injection molded, and a metal insert is embedded in the process of injection molding of the lower shell.

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