A motor driver

Abstract

The utility model relates to motor drive technical field, especially relates to a kind of motor driver, the motor driver includes shell and driver board, driver board is set in the inner chamber of shell, and the inner chamber is divided into first space and second space, first space is filled with waterproof adhesive layer;Driver board sets up breathable structure, breathable structure communicates first space and second space, by above-mentioned setting, can balance the air pressure between first space and second space in the motor driver operating process, improve the stability of motor driver.

Description

Technical Field

[0001] This utility model relates to the field of motor drive technology, and in particular to a motor driver. Background Technology

[0002] For integrated motors used in humid or corrosive environments such as outdoor spaces and warehouses, the long-term reliability of their built-in drivers is crucial. Currently, potting compound is commonly used to encapsulate the entire driver's electronic components to prevent water ingress or moisture damage. However, when the motor is operating, its power devices generate heat, leading to a significant increase in internal temperature. Since the coefficient of thermal expansion of the potting compound is much higher than that of the driver housing and the substrate of the power devices, this imbalance can cause the circuit board to be pushed upwards by the expanding potting compound, creating gaps between the power devices and the thermally conductive surface of the housing. This increases contact thermal resistance, affects heat dissipation, and in severe cases, can lead to overheating and damage to the devices, affecting the stability of the driver. Therefore, how to waterproof the motor in harsh environments without compromising the reliability of the driver has become a pressing technical problem to be solved in this field. Utility Model Content

[0003] To address the problem of poor heat dissipation caused by the heat generated after waterproofing with potting compound in existing motor drivers, this invention provides a motor driver comprising a housing and a driver board. The driver board is disposed within the inner cavity of the housing, dividing the inner cavity into a first space and a second space. The first space is potted with a waterproof adhesive layer. The driver board is provided with a ventilated structure that connects the first space and the second space.

[0004] In one embodiment, the driver board includes a circuit board and power devices fixedly connected to the circuit board.

[0005] In one embodiment, the breathable structure passes through the waterproof adhesive layer and is exposed in a first space outside the waterproof adhesive layer, and the breathable structure is integrally formed with or detachably connected to the circuit board.

[0006] In one embodiment, the breathable structure includes a breathable plug having a breathable channel, a waterproof and breathable membrane being disposed within the breathable channel, one end of the breathable channel passing through the waterproof adhesive layer and extending into the first space exposed outside the waterproof adhesive layer, and the other end of the breathable channel communicating with the second space.

[0007] In one embodiment, the breathable structure further includes a waterproof and breathable valve disposed within the breathable channel, and the waterproof and breathable membrane is disposed on the waterproof and breathable valve.

[0008] In one embodiment, a sealing element is provided between the circuit board and the housing, and the sealing element abuts against the periphery of the circuit board and the inner side of the housing, respectively.

[0009] In one embodiment, the sealing element is a sealing ring or silicone rubber; when the sealing element is the sealing ring, the contact portion between the sealing ring and the periphery of the circuit board has a groove, and the circuit board is embedded in the groove; the contact portion between the sealing ring and the inner side of the housing has a bevel, and the sealing ring is interference-fitted with the inner side of the housing.

[0010] In one embodiment, the power device is an IGBT module or a MOSFET module, and a heat-conducting layer is provided on the side of the power device that contacts the housing. Heat dissipation ribs are provided on the housing corresponding to the position of the heat-conducting layer.

[0011] In one embodiment, the power device has a first mounting hole at its end, and the power device is fixed to the housing through the first mounting hole.

[0012] In one embodiment, the circuit board is further provided with a through hole at the position corresponding to the first mounting hole, and a sealing member is provided in the through hole, the sealing member being interference-fitted with the through hole.

[0013] Based on the above, compared with the prior art, the motor driver provided by this utility model has at least the following technical effects: 1. By utilizing the ventilated structure set on the driver board, air can circulate in the space on both sides of the driver board to achieve the ventilation function and balance the air pressure between the first space and the second space. 2. By setting a sealing ring around the circuit board, and filling the through holes of the circuit board with sealing plugs and vent plugs, the vent plugs have waterproof and breathable functions, and the waterproof glue layer is filled in the first space, which greatly increases the waterproof effect of the driver. 3. A heat-conducting layer is provided on the side of the power device close to the housing, and heat dissipation ribs are provided on the housing at the position corresponding to the heat-conducting layer, which can reduce contact thermal resistance and improve heat dissipation efficiency.

[0014] Other features and beneficial effects of this invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other beneficial effects of this invention can be realized and obtained through the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Unless otherwise specified, the positional relationships shown in the drawings in the following description are based on the direction in which the components are drawn in the figure.

[0016] Figure 1 A top view of the motor driver provided in Embodiment 1 of this utility model; Figure 2 for Figure 1 Sectional view at CC; Figure 3 for Figure 1 Sectional view at AA; Figure 4 This is a cross-sectional view of the motor driver provided in Embodiment 2 of this utility model; Figure 5 This is a cross-sectional view of the motor driver provided in Embodiment 3 of this utility model; Figure 6 for Figure 3 A magnified view of a portion at point A; Figure 7 for Figure 5 A magnified view of a section at point B.

[0017] Figure label: 1. Housing; 11. Heat dissipation fins; 2. Driver board; 21. Power device; 211. Thermal conductive layer; 212. Elastic sheet; 213. First mounting hole; 22. Circuit board; 221. Through hole; 222. Sealing component; 223. Vent hole; 224. Second mounting hole; 3. First space; 4. Second space; 5. Waterproof adhesive layer; 6. Ventilation structure; 61. Vent plug; 611. Vent channel; 612. Waterproof and breathable valve; 613. Waterproof and breathable membrane; 7. Sealing component; 8. First fastener; 9. Second fastener. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The technical features designed in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model.

[0019] In the description of this utility model, it should be noted that all terms used in this utility model (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model pertains, and should not be construed as limiting this utility model; it should be further understood that the terms used in this utility model should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this utility model.

[0020] Example 1 Please see Figures 1-3 This utility model provides a motor driver, including a housing 1 and a driver board 2. The driver board 2 is disposed in the inner cavity of the housing 1, dividing the inner cavity into a first space 3 and a second space 4. A waterproof adhesive layer 5 is potted on the first space 3 for moisture protection and insulation. During potting, the pins of the components on the driver board 2 need to be buried. The depth of the first space 3 is greater than the thickness of the waterproof adhesive layer 5. A ventilated structure 6 is provided on the driver board 2, which can connect the first space 3 and the second space 4 to balance the air pressure between the first space 3 and the second space 4.

[0021] Specifically, the driver board 2 includes a circuit board 22 and a power device 21 fixedly connected to the circuit board 22. The two are fixed by welding, screws or other methods. The circuit board 22 divides the housing 1 into a first space 3 and a second space 4. A ventilated structure 6 is provided on the circuit board 22. One end of the ventilated structure 6 passes through the waterproof adhesive layer 5 and is exposed in the first space 3 outside the waterproof adhesive layer 5. The other end extends into the second space 4 so that the ventilated structure 6 can connect the first space 3 and the second space 4. The ventilated structure 6 can be integrally formed with the circuit board 22 or detachably connected to adapt to different installation requirements.

[0022] Furthermore, the breathable structure 6 is detachably connected to the circuit board 22; such as Figure 6The breathable structure 6 includes a breathable plug 61, which has a breathable channel 611. One end of the breathable channel 611 passes through the waterproof adhesive layer 5 and extends axially along the breathable plug 61 into a first space 3 exposed outside the waterproof adhesive layer 5, while the other end extends into a second space 4. A waterproof breathable valve 612 is provided inside the breathable channel 611. The diameter of the breathable hole of the waterproof breathable valve is 2.5 mm, and a waterproof breathable membrane 613 is provided on the top of the waterproof breathable valve 612 to achieve the breathable function. The waterproof breathable valve 612 can be used with breathable plugs 61 of different specifications, providing flexibility. Furthermore, the waterproof and breathable membrane 613 has a microporous structure with pore sizes of 0.1~10um. Since the diameter of air molecules is 0.0002~0.0004um, the diameter of water vapor molecules is 0.0004um, and the diameter of liquid water molecules is 100um, the waterproof and breathable membrane 613 has a waterproof function while allowing air to pass through. When water comes into contact with the waterproof and breathable membrane 613, the water cannot enter below the circuit board 22. After the moisture on the surface of the waterproof and breathable membrane 613 evaporates, the waterproof and breathable membrane 613 will regain its breathability.

[0023] To facilitate installation, the power device 21 has at least one elastic piece 212 at its end, specifically two in this embodiment, respectively located at both ends of the power device 21 near the housing 1. Each elastic piece 212 has a first mounting hole 213, through which a first fastener 8 passes to fix it to the housing 1. Correspondingly, the circuit board 22 also has a second mounting hole 224, through which a second fastener 9 passes to fix it to the housing 1. The first fastener 8 and the second fastener 9 are bolts, and an alternating tightening method is used during installation to ensure uniform pressure. Due to installation process requirements, the circuit board 22... A through hole 221 is also provided at the position corresponding to the first mounting hole 213. This is a process hole, which is used to lock the power device 21 to the housing 1 during installation. There are two through holes 211. One through hole 211 is equipped with a sealing element 222, such as a sealing plug. The sealing element 222 is interference-fitted with the through hole 221, and the compression is about 0.2mm. The other through hole 211 is equipped with a vent plug 61, which is a vent plug. It is interference-fitted with the through hole 211, and the compression is about 0.2mm, to prevent glue from seeping in. If there is a different installation process, such as fixing the power device 21 from the outside of the housing 1 with fasteners, the through hole 211 may not be provided.

[0024] To ensure airtightness, a sealing element 7 is provided between the circuit board 22 and the housing 1. The sealing element 7 abuts against the outer periphery of the circuit board 22 and the inner side of the housing 1. The sealing element 7 is specifically a sealing ring. The contact part of the sealing ring with the outer periphery of the circuit board 22 is designed to have a groove, and the contact part with the inner side of the housing 1 is designed to have a bevel. When assembling the circuit board 22, the circuit board 22 is embedded in its groove. The bevel of the sealing ring is interference-fitted with the inner wall of the housing, and its compression is about 0.5mm. When a small amount of water enters the driver, the double protection of the waterproof adhesive layer 5 and the sealing element 7 prevents water from entering the second space 4.

[0025] Power device 21 is a module such as IGBT or MOSFET that generates heat during operation. In this embodiment, an IGBT module is specifically used as power device 21. When the driver is working, since the housing 1 and the motor flange are sealed together, the space inside the housing 1 can be considered closed, that is, the first space 3 and the second space 4 are closed spaces. Since the operation of the power device 21 generates heat, the temperature of the space where the power device 21 is located, namely the second space 4, will rise rapidly, much faster than the temperature rise rate of the first space 3. This causes the air expansion in the second space 4 to be greater than that in the first space 3. Therefore, some air in the second space 4 will pass through the ventilation channel 611 into the first space 3 to balance the air pressure in the two spaces and bring them closer to equal. When the driver stops working, the temperature rise in the second space 4 will gradually decrease. When the temperature drops to the point where the air expansion in the second space 4 is less than that in the first space 3, some air in the first space 3 will flow back into the second space 4 through the ventilation channel 611. The airflow between the first space 3 and the second space 4 through the ventilation channel 611 mentioned above can balance the air pressure difference caused by temperature changes and prevent the PCB board from being deformed by pressure. The air permeability requirement of the waterproof vent valve 612 is calculated under extreme conditions, considering only the temperature rise of the second space 4 while ignoring the temperature rise of the first space 3. It also disregards the impact of the temperature rise and pressure increase in the first space 3 caused by air entering from the second space 4, which reduces the air permeability. During operation, the IGBT module raises the temperature in the second space 4 to 60°C within one minute. Assuming an air volume of 150ml in the second space 4, the air will expand to approximately 180ml, requiring the discharge of about 30ml of air. Based on the vent diameter of the waterproof vent valve 612 being 2.5mm, the designed air permeability of the waterproof vent valve 612 is approximately 100ml / min.

[0026] Furthermore, a thermally conductive layer 211 is provided on the side where the power device 21 contacts the housing 1. The thermally conductive layer 211 can be made of metal or silicone-based materials. In this embodiment, thermally conductive silicone grease is specifically used as the thermally conductive layer 211. It is applied quantitatively and uniformly on the contact surface between the power device 21 and the housing 1 using a special tool. In addition, heat dissipation ribs are provided on the housing 1 at the position corresponding to the thermally conductive layer 211, which can improve the heat dissipation effect of the driver.

[0027] Specifically, the process steps of the motor driver in this embodiment are as follows: First, the sealing element 7 is sleeved around the circuit board 22. Then, thermal conductive silicone grease is applied to the thermally conductive contact surface of the power device 21. The driver board 2 is placed into the housing 1 according to the assembly position. The power device 21 and the circuit board 22 are locked onto the housing 1 alternately. The vent plug 61 and the sealing element 222 are installed. The waterproof vent valve 612 is pressed into the vent channel 611. The driver power lead and signal lead are connected. Finally, a certain amount of glue is poured into the first space 3 and waited for it to solidify.

[0028] Example 2 refer to Figure 4 This utility model also provides a motor driver in which the sealing element 7 is made of silicone instead of the sealing ring solution in Embodiment 1. It can also achieve the sealing and waterproofing function between the circuit board 22 and the housing 1. Due to the characteristics of silicone, during assembly, silicone is first applied to the joint between the circuit board 22 and the housing 1 and allowed to solidify before the potting operation is performed.

[0029] Example 3 refer to Figure 5 , Figure 7 This embodiment also provides a motor driver in which a waterproof and breathable valve 612 is not provided in the breathable channel 611 of the breathable plug 61. Instead, the waterproof and breathable membrane 613 is directly integrated into the breathable channel 611 by means of hot pressing or ultrasonic welding to form an integral structure. While achieving the same waterproof and breathable function, it simplifies the number of components and reduces costs.

[0030] In summary, compared with the prior art, the motor driver provided by this utility model improves the operational stability of the driver by setting a venting device on the driver plate, which connects the driver plate to the two spaces divided by the housing, thereby balancing the temperature and air pressure of the two spaces.

[0031] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of this utility model can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0032] Although this document frequently uses terms such as power devices and breathable structures, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of this invention; interpreting them as any kind of additional limitation would contradict the spirit of this invention. The terms "first," "second," etc. (if present), in the description, claims, and accompanying drawings of the embodiments of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A motor driver, characterized in that: The device includes a housing and a driver board. The driver board is disposed in the inner cavity of the housing and divides the inner cavity into a first space and a second space. The first space is filled with a waterproof adhesive layer. The driver board is provided with a ventilated structure that connects the first space and the second space.

2. The motor driver according to claim 1, characterized in that: The driver board includes a circuit board and power devices fixedly connected to the circuit board.

3. The motor driver according to claim 2, characterized in that: The breathable structure passes through the waterproof adhesive layer and is exposed in a first space outside the waterproof adhesive layer. The breathable structure is integrally formed with the circuit board or is detachably connected.

4. The motor driver according to claim 1, characterized in that: The breathable structure includes a breathable plug with a breathable channel. A waterproof and breathable membrane is disposed within the breathable channel. One end of the breathable channel passes through the waterproof adhesive layer and extends into the first space exposed outside the waterproof adhesive layer. The other end of the breathable channel connects to the second space.

5. The motor driver according to claim 4, characterized in that: The breathable structure also includes a waterproof and breathable valve disposed within the breathable channel, and the waterproof and breathable membrane is disposed on the waterproof and breathable valve.

6. The motor driver according to claim 2, characterized in that: A sealing element is provided between the circuit board and the housing, and the sealing element abuts against the outer periphery of the circuit board and the inner side of the housing respectively.

7. The motor driver according to claim 6, characterized in that: The sealing element is a sealing ring or silicone rubber; when the sealing element is the sealing ring, the contact portion between the sealing ring and the periphery of the circuit board has a groove, and the circuit board is embedded in the groove; the contact portion between the sealing ring and the inner side of the housing has a bevel, and the sealing ring is interference-fitted with the inner side of the housing.

8. The motor driver according to claim 2, characterized in that: The power device is an IGBT module or a MOSFET module. A heat-conducting layer is provided on the side of the power device that contacts the housing. Heat dissipation ribs are provided on the housing corresponding to the position of the heat-conducting layer.

9. The motor driver according to claim 2, characterized in that: The power device has a first mounting hole at its end, and the power device is fixed to the housing through the first mounting hole.

10. The motor driver according to claim 9, characterized in that: The circuit board also has a through hole at the position corresponding to the first mounting hole, and a sealing member is provided in the through hole, the sealing member being interference fit with the through hole.

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