WO2024067534A1

WO2024067534A1 - Lateral acceleration sensor for multiple-unit train and potting method therefor

Info

Publication number: WO2024067534A1
Application number: PCT/CN2023/121315
Authority: WO
Inventors: 林旭光; 王文军; 周博; 张君颖
Original assignee: 中车长春轨道客车股份有限公司
Priority date: 2022-09-29
Filing date: 2023-09-26
Publication date: 2024-04-04
Also published as: CN115555221A; CN115555221B

Abstract

The present disclosure relates to the technical field of potting. Provided are a lateral acceleration sensor for a multiple-unit train and a potting method therefor. Specifically, the method comprises four independent potting steps, wherein the angle of a sensor, the potting position and potting limitation during potting, and treatment modes for standing are defined, such that bubbles possibly generated during potting processes are avoided to the utmost extent; namely, the probability of generating bubbles during potting processes of lateral acceleration sensor products is minimized or even no bubble is generated, thereby avoiding the generation of bubbles in metal casings of lateral acceleration sensors after the potting is completed, thus solving the problem that bubbles present in resin nearby components due to anomalies of potting processes cause damages to welding spots of components and thus eventually lead to open circuits of components, reducing the probability of failures of lateral acceleration sensors and effectively prolonging the service life of lateral acceleration sensors.

Description

A lateral acceleration sensor for EMU and its glue filling method

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Chinese patent application number 202211198090.0, filed with the Chinese Patent Office on September 29, 2022, and entitled “A lateral acceleration sensor for EMUs and its glue filling method”, the entire contents of which are incorporated by reference into this application.

Technical Field

The present disclosure relates to the technical field of glue injection, and in particular to a lateral acceleration sensor for an EMU and a glue injection method thereof.

Background technique

High-speed EMUs play an important role in high-speed, safe, and large-volume transportation, and have high requirements for the safety and systematization of high-speed EMUs. Sensors are devices that convert measurement parameters into electrical signals or other required information outputs in a certain pattern. They are an indispensable and important part of the safety control system of the entire rail transit industry. At the same time, the integration mechanism of high-speed train pedigree and health management platform to form a high-speed train pedigree product technology platform for fault prediction and health management (Prognostics and Health Management, PHM) also relies heavily on real-time monitoring of sensors. At present, by installing lateral acceleration sensors on the bogies of high-speed EMUs, high-speed EMUs are monitored in real time using lateral acceleration sensors to ensure that the trains are running in normal or optimal conditions. However, when the lateral acceleration sensor fails, the EMU needs to limit speed or even stop, which has a great impact on operations and also affects the planning of subsequent health management.

At present, the most common cause of lateral acceleration sensor failure is electrical failure of circuit components inside the lateral acceleration sensor during long-term operation, such as short circuit or open circuit of components. In particular, due to temperature changes, the probability of failure in different seasons is different. Therefore, it is necessary to provide a method to improve the quality of lateral acceleration sensors, increase the service life of lateral acceleration sensors, and thereby improve the safety of EMUs.

Application Contents

The first purpose of the present disclosure is to provide a glue injection method for a lateral acceleration sensor for an EMU, through which the sensor can maintain its original function in a low temperature environment and the failure rate is greatly reduced.

In order to achieve the above-mentioned purpose of the present disclosure, the following technical scheme is specially adopted: the glue pouring method comprises the following steps:

(1) First glue pouring: adjust the position of the lateral acceleration sensor to be glued so that the angle formed by the bottom surface of the sensor and the horizontal plane meets the preset angle; pour glue at the first glue injection point until the glue seeps out from the bottom of the sensor circuit board, stop pouring glue and perform the first static state;

(2) Second glue pouring: Control the position of the sensor so that the angle formed by the bottom surface of the sensor and the horizontal plane meets the preset angle; pour glue at the first glue injection point until the height of the glue reaches the highest point of the bottom surface of the metal shell of the sensor, stop pouring glue and perform a second static state;

(3) Third glue pouring: adjust the bottom surface of the sensor to keep it parallel to the horizontal plane; pour glue at the second glue injection point until the height of the glue reaches the top of the inner side of the metal shell of the sensor, stop pouring glue and let it stand for the third time;

(4) Fourth glue pouring: adjust the bottom surface of the sensor to keep it parallel to the horizontal plane; pour glue until the height of the glue reaches the outer top of the metal shell of the sensor, stop pouring glue and perform the fourth static state;

The first glue injection point is the lowest point of the top surface of the metal shell close to the sensor, and the second glue injection point is the highest point of the glue surface close to the sensor in step (3).

Furthermore, the preset angle is 3° to 15°; further, the preset angle is 5° to 8°.

Furthermore, the first static time is 2 minutes to 5 minutes, and the angle formed by the bottom surface of the sensor and the horizontal plane during the first static time satisfies a preset angle;

Furthermore, the second static time is 2 minutes to 5 minutes, and the bottom surface of the sensor is kept parallel to the horizontal plane during the second static time;

Furthermore, the third static time is 2 minutes to 5 minutes, and the bottom surface of the sensor is kept parallel to the horizontal plane during the third static time;

Furthermore, the fourth standing time is 20 hours to 25 hours, and the bottom surface of the sensor is kept parallel to the horizontal plane during the fourth standing time.

Furthermore, before step (1), the sensor is placed in a clamping assembly, and the clamping assembly includes a glue pouring groove; further, the sensor is fixed in the glue pouring groove.

Furthermore, before step (1), the clamping assembly is dried; further, the drying treatment includes: drying under hot air at 60°C to 90°C for 3min to 10min, cooling for 2min to 5min, drying under hot air again for 3min to 10min, cooling for 5min to 10min, and then performing step (1).

Furthermore, before step (1), the sensor is subjected to a vacuum treatment.

Furthermore, in step (1), the sensor is subjected to vibration treatment during the glue pouring process; further, the frequency of the vibration treatment is 25Hz to 60Hz; further, the vibration treatment is performed for 1min to 2min, and then it is left to stand for 2min to 5min, and the vibration treatment and the standing still are repeated until the first glue pouring is completed.

Furthermore, a plurality of exhaust holes are arranged on the metal shell surface of the sensor.

The second objective of the present disclosure is to provide a lateral acceleration sensor for an EMU prepared by the glue pouring method for the lateral acceleration sensor for an EMU.

Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention optimizes the glue injection process from the conventional two times to four times, and maintains the inclination state at a preset angle during the first and second times of glue injection, so that all the air inside the sensor is easier to be discharged from the top side of the sensor; at the same time, the glue injection points, cut-off positions and static methods of the four times of glue injection are clearly defined. The present invention improves and optimizes the glue injection process to minimize or remove bubbles that may be generated in the glue injection process, and reduces the probability of bubbles generated in the lateral acceleration sensor product during the glue injection process to a minimum or even zero bubbles, thereby avoiding the generation of bubbles in the metal shell of the lateral acceleration sensor after the glue injection is completed, and solves the problem that bubbles in the colloid near the component due to abnormal glue injection process cause damage to the component solder joints, and finally cause the component to open circuit, thereby reducing the failure probability of the lateral acceleration sensor and effectively improving the service life of the lateral acceleration sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the specific embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the specific embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

FIG1 is a structural diagram of a clamping assembly provided by the present disclosure;

FIG2 is a schematic diagram of a clamping assembly provided by the present disclosure;

FIG3 is a structural diagram of a lateral acceleration sensor provided by the present disclosure;

FIG4 is a schematic diagram of the first glue pouring in the embodiment of the present disclosure;

FIG5 is a schematic diagram of the second glue pouring in the embodiment of the present disclosure;

FIG6 is a schematic diagram of the third glue pouring in the embodiment of the present disclosure;

FIG. 7 is a schematic diagram of the fourth glue pouring in the embodiment of the present disclosure.

Detailed ways

The technical solution of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but those skilled in the art will understand that the embodiments described below are part of the embodiments of the present disclosure, rather than all of the embodiments, and are only used to illustrate the present disclosure, and should not be considered to limit the scope of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

In the description of the present disclosure, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

In the description of the present disclosure, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

During the long-term operation of the EMU, the circuit components inside the lateral acceleration sensor may have electrical failures, such as short circuit or open circuit of the components. In particular, due to the change of temperature, the probability of failure in different seasons is different. The analysis of the reasons for the failure of the lateral acceleration sensor shows that the manifestation of its failure is short circuit or open circuit of the components, but the root cause of the short circuit or open circuit is the bubbles of the colloid on the sensor circuit board. The root cause of this phenomenon is that the components on the circuit board are wrapped by the glue material under normal conditions, but due to the different thermal expansion coefficients of different metal components and glue materials, the components may be subjected to force. When the glue filling is normal, the circuit board (or other metal components) of the lateral acceleration sensor is completely covered by the glue material to form an effective adhesion, and there is no relative extension or contraction force between the circuit board and the glue. However, when the glue filling is not good (such as bubbles in the colloid, uneven glue, or no effective contact between the colloid and the circuit board), if some metal components are not covered with the glue material, thermal expansion will cause force to act on the solder joints; over time, cracks may appear on the colloid after the solder joints are subjected to force. In summary, it can be concluded that due to the abnormality of the glue filling process, the solder joints of some components were affected and failed under the influence of thermal stress, which in turn caused the component to open circuit and the electrical failure of the lateral acceleration sensor.

The colloid used in the glue filling process of the lateral acceleration sensor is usually a polyurethane adhesive, which is a mixture of a hydroxyl compound (main agent) and an isocyanate (curing agent) in a volume ratio of 4:1. Bubbles usually appear during the glue filling process. There are two main reasons: first, isocyanate reacts with moisture in the air to produce carbon dioxide gas; second, the air inside the product is not completely discharged during the glue filling process. It is clear to those skilled in the art that for colloids with low viscosity, the gas is easily discharged; however, the lower the isocyanate content in the colloid, the fewer bubbles are produced during the curing process, but the lower the bonding strength. To ensure product performance, the isocyanate content must be controlled within a moderate range. The mixed viscosity of the colloid used in the sensor is 1300mPa·s at 25°C. It takes 25 minutes for the mixed viscosity to reach 5000mPa·s after standing. The gel time is usually 70 minutes, and the complete curing cycle at room temperature is 24 hours. After analyzing the glue filling process, the inventors found that the problem of bubbles generated at the joint surface of the sensor circuit board and the colloid can be improved by improving the glue filling process technology. In particular, the process node time and the control of the glue amount are crucial for the discharge of gas inside the sensor.

Based on this, it is necessary to provide a method for filling glue for a lateral acceleration sensor for a train set to solve the technical problem of how to avoid electrical failure of circuit components inside the lateral acceleration sensor during long-term operation, so as to improve the quality of the sensor; specifically, the present disclosure is carried out through the following implementation methods:

(1) First glue pouring: adjust the position of the lateral acceleration sensor to be glued so that the angle formed by the bottom surface of the sensor and the horizontal plane meets the preset angle; perform glue pouring at the first glue pouring point until the glue seeps out of the bottom of the sensor circuit board, stop glue pouring and perform the first static rest; (2) Second glue pouring: control the position of the sensor so that the angle formed by the bottom surface of the sensor and the horizontal plane meets the preset angle; perform glue pouring at the first glue pouring point until the glue height reaches the highest point of the bottom surface of the metal shell of the sensor, stop glue pouring and perform the second static rest; (3) Third glue pouring: adjust the bottom surface of the sensor to keep it parallel to the horizontal plane; perform glue pouring at the second glue pouring point until the glue height reaches the highest point of the bottom surface of the metal shell of the sensor, stop glue pouring and perform the second static rest; (4) the fourth glue pouring: adjusting the bottom surface of the sensor to be parallel to the horizontal plane; pouring glue, and when the height of the glue reaches the top of the outer side of the metal shell of the sensor, stopping the glue pouring and letting it stand for the fourth time; wherein the lateral acceleration sensor to be poured with glue refers to a semi-finished sensor which is wrapped by a metal shell on the outside and has components welded on a circuit board inside and has not been poured with glue and packaged; the first glue injection point is the lowest point close to the top surface of the metal shell of the sensor, and the second glue injection point is the highest point close to the glue surface of the sensor in step (3).

As an implementation manner, the preset angles include but are not limited to: 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, and 15°.

For the first glue pouring: since the angle formed by the bottom surface of the sensor and the horizontal plane meets the preset angle, it means that the sensor is in a tilted state in the conventional sense; when the preset angle is met, it can be ensured that the glue covers a wider area at one time. The selection of the glue injection point and the cut-off position in this step are both optimization processes summarized after multiple experiments. The purpose is to utilize the structural characteristics of the sensor to be glued, and the effects of gravity and air pressure. In a tilted state, the bubbles generated during the first glue injection process can float out of the liquid surface of the first grouting glue. The definition of the cut-off position is to provide a mechanical advantage for the bubbles to float out of the liquid surface, so as to avoid the first grouting glue being too deep and the bubbles unable to float out of the liquid surface.

For the second glue pouring: since the angle formed by the bottom surface of the sensor and the horizontal plane still meets the preset angle, the gravity of the grouting glue and the effect of air pressure can also be better utilized to transfer the bubbles that may be generated during the glue pouring process.

For the third glue injection: the third glue injection is carried out from a position close to the first glue injection point, and the grouting glue liquid can be further increased on the basis of the original grouting glue to form a better continuation. The cut-off position of the third glue injection is the top of the sensor metal shell. It can be seen that when bubbles are generated in this process, the colloid liquid level after standing may not reach the top of the metal shell. In this glue injection, the cut-off position is defined as the top of the metal shell of the sensor, so that the liquid level is actually lower than the top of the metal shell after the third standing when bubbles exist, so as to better complete the fourth glue injection, and also to allow the bubbles that may be generated in this process to contact the metal shell and dissipate after standing.

For the fourth glue pouring: the injection points are not strictly limited in this glue pouring; as an optional implementation, glue can be injected from multiple points at different heights and positions at the same time, as long as the height of the colloid reaches the outer top of the metal shell of the sensor (that is, the colloid can completely wrap the metal shell of the sensor). The purpose of this implementation is: on the one hand, the fourth glue pouring can be completed quickly, and at the same time, during the glue injection process, appropriate mechanical impact is caused to the grouting glue to form micro-oscillations, so as to lift and transfer the gas that may remain in the grouting glue and dissipate the bubbles. This step also keeps the sensor parallel to the horizontal plane, with the aim of avoiding unnecessary interference factors during the fourth glue pouring process, so as to complete this glue pouring operation better and faster.

As an implementation mode, the static placement in each step has different time and placement angles, and specifically includes the following features:

(a) The first standing time includes but is not limited to 2 minutes, 3 minutes, 4 minutes, 5 minutes, and/or the angle formed by the bottom surface of the sensor and the horizontal plane during the first standing time satisfies a preset angle; the bubbles that float to the surface of the liquid during the first standing time are broken by the dilution of the slurry on the surface of the bubbles as the standing time passes, so that the bubbles dissipate on the liquid surface during the first standing time; and this process It is necessary to continue to maintain the limit of the preset angle, that is, to keep the unpackaged sensor composed of the circuit board and the components soldered on the circuit board in an inclined state, so that the glue of the first grouting glue gradually invades the circuit board and the surrounding of the components soldered on the circuit board over time, forming a better packaging effect; it can be understood that after the first glue pouring and the first standing, the bottom of the sensor metal shell and part of the circuit board are wrapped with grouting glue.

(b) The second standing time is 2 minutes, 3 minutes, 4 minutes, 5 minutes, and/or, the bottom surface of the sensor is kept parallel to the horizontal plane during the second standing; when the sensor completes the second glue injection, its angle relative to the horizontal plane is adjusted, and the original tilted state is adjusted to a horizontal state. In fact, the tilted state is maintained during the first glue injection and the first standing, and the bubbles that may be generated during the glue injection process can be floated out by gravity and air pressure; however, in order to better dissipate the bubbles in the present disclosure, the angle of the fixture relative to the operating platform is adjusted after the second glue injection, so that the second grouting glue is shaken during the adjustment process, and this shaking process can lift the bubbles in the liquid, so that the bubbles float out of the liquid surface and then stand still to dissipate. It can be understood that in this standing, during the process of adjusting the angle, since the grouting glue is still in liquid form, the glue obtained by the first glue injection will also flow during this adjustment process, and this flow can further squeeze the bubbles that may remain, and then squeeze them above the liquid surface to dissipate.

(c) The third standing time is 2 minutes, 3 minutes, 4 minutes, 5 minutes, and/or, the bottom surface of the sensor is kept parallel to the horizontal plane during the third standing time; since the cut-off position of the third glue pouring is the top of the sensor metal shell, when bubbles are generated during the third glue pouring, the bubbles will dissipate in the liquid surface of the grouting glue over time, and the height of the liquid surface will be lower than the top of the sensor metal shell. If no bubbles are generated during the third glue pouring, the liquid surface height of the grouting glue will remain unchanged over time and will still be at the top of the sensor metal shell.

(d) The fourth standing time is 20h, 21h, 22h, 23h, 24h, 25h, and/or, the bottom surface of the sensor remains parallel to the horizontal plane during the fourth standing time; in fact, after the fourth grouting is completed and before it has been standing for 20 to 25 hours, the grouting glue is still in liquid form, and the grouting glue will only solidify into a solid form after a long period of standing; and this long period of standing again utilizes gravity and air pressure to eliminate possible remaining bubbles (but generally there are basically no bubbles in the grouting glue before this standing time).

As an embodiment, the glue pouring method described in the present disclosure is implemented through a clamping assembly, and the clamping assembly at least includes a glue pouring groove; the glue pouring groove is used to accommodate the sensor so as to gather the grouting glue through the glue pouring groove, and after cooling, the circuit board and the components soldered on the circuit board can be glued and packaged together.

As another embodiment, the clamping assembly may further include: a hand-held portion (such as a grip, a handle, etc.), a supporting portion supporting the glue pouring tank, a connecting portion connecting the hand-held portion and the glue pouring tank, etc.; The specific structure of the clamping assembly is limited to clamping and fixing the sensor without affecting the glue injection of the sensor, which can avoid the sensor moving during the glue injection process and affecting the glue injection quality or efficiency. Figure 1 shows a feasible clamping assembly, including a glue injection groove and a handle.

As another further implementation manner, the glue pouring method described in the present disclosure is implemented by a glue pouring device; the glue pouring device integrates equipment for glue pouring, an operating plane and at least one clamping component; as an optional implementation manner, as shown in Figure 2, by placing a plurality of the clamping components in parallel on the operating plane of the glue pouring device, batch and large-scale production can be achieved.

As a further embodiment, before step (1), the clamping assembly is dried to remove moisture from the surface of the clamp. That is, the clamping assembly is dried to remove moisture, so as to avoid the injection of grouting glue when moisture remains in the clamp, and the grouting glue is solidified and the water evaporates to cause bubbles.

As a further implementation, the drying process includes: drying at 60℃～90℃ for 3min～10min, cooling for 2min～5min, drying with hot air again for 3min～10min, and cooling for 5min～10min; on the one hand, the hot air can heat the fixture (especially the bottom, side walls and other positions of the glue filling groove of the heating fixture), so that the water attached to the bottom, side walls and other positions of the glue filling groove evaporates, and on the other hand, the flowing hot air can drive the evaporated water to leave the fixture, thereby completing the drying of the fixture. The method of using two hot air drying is because: when heating and ventilating once, it is inevitable that some water will remain at the bottom, side walls and other positions of the glue filling groove for various reasons, and thus the water (water vapor) cannot be completely removed. The two hot air dryings not only improve the drying efficiency, but also indirectly improve the yield of the glue injection process.

As a further implementation, before step (1), the sensor is vacuumed to discharge the moisture mixed in the air in the clamp. Affected by the storage environment of the sensor or the air contained in the clamping assembly itself, especially when the moisture content in the air is high, the grouting glue will still be mixed; when the air humidity is high, the moisture in the air will also affect the quality of the grouting glue after solidification, that is, bubbles will be generated. To avoid such problems, this implementation can be adopted and the glue filling method disclosed in this disclosure can be implemented in a relatively dry environment.

As a further implementation, in step (1), the sensor is subjected to vibration treatment during the glue pouring process; as a further implementation, the frequency of the vibration treatment is 25Hz to 60Hz; the vibration treatment is performed for 1min to 2min, and then the sensor is left to rest for 2min to 5min, and the vibration treatment and rest are repeated until the first glue pouring is completed. This implementation can accelerate the dissipation speed of small bubbles, so that the small bubbles generated during the glue injection process are lifted and floated on the surface of the grouting glue liquid and then dissipated.

As a further implementation, for the above-mentioned vibration treatment, during the glue pouring process in step (1), when the preset angle formed by the bottom surface of the sensor and the horizontal plane is of different parameter values, different vibration process parameters can be used.

Specifically: When the preset angle is 6°: the vibration time is 1 minute, the vibration frequency is 50 Hz, and after the vibration is completed, let it stand for 3 minutes. When the preset angle is 5°: the vibration time is 1 minute, the vibration frequency is 60 Hz, and after the vibration is completed, let it stand for 5 minutes. When the preset angle is 8°: the vibration time is 2 minutes, the vibration frequency is 25 Hz, and after the vibration is completed, let it stand for 2 minutes. It can be understood that: the vibration duration, vibration frequency and standing time after vibration can be determined according to the specific operating environment. For example, when the injection process of the glue for the first time is relatively smooth, it can be understood that the probability of small bubbles generated during the injection process is small, or the number of small bubbles generated is small. At this time, short vibration time, low vibration frequency and short standing time after vibration can be used for vibration operation, and so on.

As an implementation mode, since the sensor to be glued is wrapped by a metal shell on the outside, and the grouting glue also wraps the metal shell after the glue is filled, in order to improve the efficiency of air bubble discharge during the glue injection process, a plurality of exhaust holes are provided on the metal shell surface of the sensor.

As another embodiment, the diameter of the exhaust hole is smaller than the diameter of the hole on the metal shell of a conventional sensor. As yet another embodiment, the exhaust holes are distributed on the top and side surfaces of the metal shell. As yet another embodiment, the exhaust holes are regularly distributed in a matrix. Figure 3 shows a feasible sensor structure: a circuit board is connected to a metal shell, and the metal shell covers the components soldered on the circuit board; a plurality of circular exhaust holes of the metal shell are provided, which are respectively located on the top and side of the metal shell and are regularly arranged in a matrix. By optimizing the metal shell inside the sensor and improving its air permeability by changing the size and number of the ventilation holes of the metal shell, bubbles can be avoided during glue filling.

Example

Step 1: Place the sensor to be glued on the fixture as shown in FIG1 , and the fixture is placed on the plane of the operating platform, and the plane of the operating platform is parallel to the horizontal plane.

Step 2: Adjust the angle of the clamp relative to the plane of the operating platform to a preset angle, wherein the preset angle is 6°.

Step 3: Perform the first glue injection from the glue injection point at one end of the fixture close to the operating platform, and stop the glue injection when the glue seeps out from the bottom of the circuit board of the sensor to be glued. As shown in Figure 4, the glue injection point and the glue phase liquid level after this glue injection are given.

Step 4: After the first injection of glue is completed, the fixture is kept at an angle of 6° relative to the plane of the operating platform and left to stand for 3 minutes.

Step 5: Keep the angle relationship of the fixture (6°), and perform a second injection of glue from the injection point of the sensor to be injected with glue close to the operating platform. Stop the injection of glue when the height of the glue reaches the top position of the bottom side of the sensor metal shell. As shown in Figure 5, the injection point and the glue phase liquid level after this injection are given.

Step 6: After the second injection of glue into the sensor to be injected, adjust the angle of the fixture relative to the plane of the operating platform to 0° and let it stand for 3 minutes.

Step 7: Keep the angle relationship of the fixture (0°), and perform the third glue injection from the bottom of the fixture near the existing glue injection point, and stop the glue injection when the glue height reaches the top of the sensor metal shell. As shown in Figure 6, the glue injection point and the glue phase liquid level after this glue injection are given.

Step 8: After the third injection of glue is completed for the sensor to be glued, the angle relationship of the fixture is maintained (0°) and left to stand for 3 minutes.

Step 9: Keep the angle relationship of the fixture (0°), and perform the fourth injection of glue from the injection points at the bottom, middle and top of the fixture, and stop injecting glue when the height of the glue reaches the top edge of the sensor metal shell. As shown in Figure 7, the injection points and the glue phase liquid level after this injection are given.

Step 10: After the fourth injection, the angle relationship of the fixture is maintained (0°) and allowed to stand for 24 hours.

Industrial Applicability

In summary, the present disclosure provides a method for glue pouring a lateral acceleration sensor for an EMU, which minimizes or removes bubbles that may be generated in the glue pouring process by improving and optimizing the glue pouring process, and reduces the probability of bubbles generated in the lateral acceleration sensor product in the glue pouring process to a minimum or even to zero bubbles, thereby avoiding the generation of bubbles in the metal shell of the lateral acceleration sensor after the glue pouring is completed, and solves the problem that bubbles in the colloid near the component due to an abnormality in the glue pouring process, causing damage to the component solder joints, and ultimately causing the component to open circuit, thereby reducing the failure probability of the lateral acceleration sensor and effectively improving the service life of the lateral acceleration sensor.

Claims

A method for glue filling of a lateral acceleration sensor for a motor vehicle unit, characterized in that it comprises the following steps:

(1) First glue pouring: adjust the position of the lateral acceleration sensor to be glued so that the angle formed by the bottom surface of the sensor and the horizontal plane meets the preset angle; pour glue at the first glue injection point until the glue seeps out from the bottom of the sensor circuit board, stop pouring glue and perform the first static state;

(2) Second glue pouring: Control the position of the sensor so that the angle formed by the bottom surface of the sensor and the horizontal plane meets the preset angle; pour glue at the first glue injection point until the height of the glue reaches the highest point of the bottom surface of the metal shell of the sensor, stop pouring glue and perform a second static state;

(3) Third glue pouring: adjust the bottom surface of the sensor to keep it parallel to the horizontal plane; pour glue at the second glue injection point until the height of the glue reaches the top of the inner side of the metal shell of the sensor, stop pouring glue and let it stand for the third time;

(4) Fourth glue pouring: adjust the bottom surface of the sensor to keep it parallel to the horizontal plane; pour glue until the height of the glue reaches the outer top of the metal shell of the sensor, stop pouring glue and perform the fourth static state;

The first glue injection point is the lowest point of the top surface of the metal shell close to the sensor, and the second glue injection point is the highest point of the glue surface close to the sensor in step (3).
The method for filling glue for a lateral acceleration sensor for an EMU according to claim 1 is characterized in that the preset angle is 3° to 15°.
The method for filling glue for a lateral acceleration sensor for an EMU according to claim 1 is characterized in that the preset angle is 5° to 8°.
The method for glue-filling a lateral acceleration sensor for an EMU according to claim 1 is characterized in that the first static time is 2 minutes to 5 minutes, and the angle formed by the bottom surface of the sensor and the horizontal plane during the first static time satisfies a preset angle;

And/or, the second standing time is 2 minutes to 5 minutes, and the bottom surface of the sensor is kept parallel to the horizontal plane during the second standing time;

And/or, the third standing time is 2 minutes to 5 minutes, and the bottom surface of the sensor is kept parallel to the horizontal plane during the third standing time;

And/or, the fourth standing time is 20 hours to 25 hours, and the bottom surface of the sensor is kept parallel to the horizontal plane during the fourth standing time.
The method for glue pouring of a lateral acceleration sensor for an EMU according to claim 1 is characterized in that, before step (1), the sensor is placed in a clamping assembly, and the clamping assembly includes a glue pouring groove.
The glue pouring method for the lateral acceleration sensor for EMU according to claim 5 is characterized in that the sensor is fixed in the glue pouring groove.
The method for glue filling of a lateral acceleration sensor for an EMU according to claim 5 is characterized in that, before step (1), the clamping assembly is dried.
The method for filling glue for a lateral acceleration sensor for a motor vehicle according to claim 7 is characterized in that the drying process comprises: drying under hot air at 60°C to 90°C for 3min to 10min, cooling for 2min to 5min, drying under hot air again for 3min to 10min, cooling for 5min to 10min, and then performing step (1).
The method for glue-filling a lateral acceleration sensor for an EMU according to claim 1 is characterized in that, before step (1), the sensor is subjected to a vacuum treatment.
The method for glue pouring of a lateral acceleration sensor for an EMU according to claim 1 is characterized in that, in step (1), the sensor is subjected to vibration treatment during the glue pouring process.
The method for glue filling of a lateral acceleration sensor for an EMU according to claim 10 is characterized in that, in step (1), the frequency of the vibration treatment is 25 Hz to 60 Hz.
The method for glue pouring of a lateral acceleration sensor for an EMU according to claim 10 is characterized in that, in step (1), the vibration treatment is performed for 1 to 2 minutes, and then the sensor is kept still for 2 to 5 minutes, and the vibration treatment and the stillness are repeated until the first glue pouring is completed.
The method for filling glue for a lateral acceleration sensor for an EMU according to claim 1 is characterized in that a plurality of exhaust holes are provided on the metal shell surface of the sensor.
A lateral acceleration sensor for an EMU prepared by the glue pouring method for a lateral acceleration sensor for an EMU as claimed in any one of claims 1 to 13.