A high sealing resistance liquid heater with electric heating rod and resistance wire

Abstract

The utility model relates to a kind of high sealing resistance resistance wire type high voltage liquid heater of electric heating rod rear plug-in type, its characteristics are: in the front end left and right positions of modified shell, cylindrical water inlet and cylindrical water outlet are respectively provided;Electric heating rod welding integrated component includes two electric heating rod bodies and shell rear end cover, it is inserted and assembled from back to front with modified shell, the front end of two electric heating rod bodies is respectively wrapped with a rubber support sleeve, the front end of two rubber support sleeves is all in contact with the front end inner wall surface of modified shell and is pressed tightly;Shell rear end cover is press-fitted and fixed in shell rear end cover mounting port;Modified water inlet end cover and modified water outlet end cover are respectively inserted and sealed with the water inlet and water outlet of modified shell through the rear cylindrical sealing portion of each;The conductor lead of electric heating rod welding integrated component is inserted and assembled with the pin hole part of modified electric control board, and is welded in the outer ring of insertion part connection.This heater facilitates assembly, improves sealing.

Description

Technical Field

[0001] This utility model belongs to the technical field of vehicle electric heaters, and particularly relates to a high-sealing resistance wire high-voltage liquid heater with a rear-mounted heating rod. Background Technology

[0002] Resistance wire high-voltage liquid heaters for new energy vehicles are mainly divided into two categories: single-ended heating rod type and double-ended heating rod type. Among them, the single-ended heating rod type occupies the mainstream market due to its mature structure, but it has the following significant technical bottlenecks in practical applications:

[0003] Redundancy defects in sealing systems: (1) In terms of assembly process: see Figure 1 The use of more than 4 sets of O-rings for multi-layer sealing makes the assembly process complicated. At the same time, the sealing surfaces required to be matched require a machining accuracy of ±0.01mm, which results in the need for fine grinding at the end of the heating rod, wasting resources. (2) Regarding reliability risks, see Figure 2 The multi-stage mechanical seal structure results in a leakage failure probability of 0.15%, significantly higher than the industry standard of <0.05% for automotive-grade thermal management components.

[0004] Electrical connection system defects: (1) Topological redundancy: see Figure 3 The control board and the heating rod are connected by multi-point press-welded terminals, with a contact impedance deviation of ±5%. (2) Regarding process complexity: see Figure 3 Specialized fixtures are required to achieve a 0.1mm level insertion and positioning accuracy, and the production line pass rate is only 82.5%.

[0005] In addition, the sealing surfaces of the heater's inlet and outlet end caps are narrow and the structure is complex, making machining difficult and increasing the risk of liquid leakage after assembly. See [link to relevant documentation]. Figure 2 The heater's main housing is large and heavy, limiting its applicability for whole-vehicle installation. (See [reference needed]). Figure 1 .

[0006] Therefore, in order to solve the many problems existing in the high-voltage liquid heater, it is necessary to simplify the sealing structure of the liquid heater and realize convenient assembly of the liquid heater. Summary of the Invention

[0007] To address the aforementioned technical problems, this utility model proposes a high-sealing resistance wire high-voltage liquid heater with a rear-inserted heating rod.

[0008] The above-mentioned objective of this utility model is achieved through the following technical solution:

[0009] A high-sealing resistance wire high-voltage liquid heater with a rear-mounted heating rod includes a modified outer shell, a welded integrated heating rod, a modified inlet end cap, a modified outlet end cap, a rubber support sleeve, a star-shaped sealing ring, and a modified electronic control board.

[0010] The modified outer shell has a water inlet chamber and a water outlet chamber arranged parallel to each other on the left and right sides, and the water inlet chamber and the water outlet chamber are connected at the rear. Cylindrical water inlet interfaces and cylindrical water outlet interfaces are respectively provided at the left and right positions of the front end of the modified outer shell, and threaded holes are provided diagonally on the outside of the water inlet interfaces and the water outlet interfaces. The water inlet interface is offset to the left side of the water inlet chamber and is connected to the front end of the water inlet chamber; the water outlet interface is offset to the right side of the water outlet chamber and is connected to the front end of the water outlet chamber. A rear end cover mounting port is provided at the rear end of the modified outer shell corresponding to the water inlet chamber and the water outlet chamber, and a sealing ring mounting groove is provided around the rear end cover mounting port.

[0011] The heating rod welding assembly includes two heating rod bodies and a rear end cover of the shell. The rear ends of the two heating rod bodies are inserted and welded to the rear end cover of the shell. The heating rod welding assembly and the modified shell body are inserted from back to front. The two heating rod bodies are respectively inserted into the water inlet cavity and water outlet cavity of the modified shell body. A rubber support sleeve is fitted around the front end of each of the two heating rod bodies. The front ends of the two rubber support sleeves are pressed against the inner wall of the front end of the modified shell body. The rear end cover of the shell body is pressed into the installation port of the rear end cover of the shell body and connected to the rear end of the modified shell body by multiple screws. A star-shaped sealing ring is embedded in the sealing ring installation groove to form a sealing fit.

[0012] Both the modified inlet end cap and the modified outlet end cap are composed of a front water pipe section, a middle flange connection section, and a rear cylindrical sealing section. Screw holes are diagonally provided on the middle flange connection section. The modified inlet end cap and the modified outlet end cap are respectively inserted and sealed to the inlet and outlet interfaces on the modified outer shell through their respective rear cylindrical sealing sections. The screw holes on the modified inlet end cap and the modified outlet end cap are aligned with the threaded holes on the outside of the inlet and outlet interfaces, respectively. By inserting screws, both the modified inlet end cap and the modified outlet end cap form a fixed, sealed connection with the front end of the modified outer shell.

[0013] The modified electronic control board is fixed inside the modified outer shell; the conductor lead of the heating rod welding assembly is inserted into the pin hole on the modified electronic control board and welded to the outer ring of the insertion part.

[0014] Furthermore, both the rear cylindrical sealing part of the modified inlet end cap and the outer ring of the rear cylindrical sealing part of the modified outlet end cap are provided with annular grooves, and O-rings are embedded in the annular grooves.

[0015] Furthermore, the ends of the conductor leads of the heating rod welding assembly are designed with a tapered surface or a wedge-shaped angle.

[0016] In addition, it also includes two rear covers, which are fitted onto the rear edge of the two heating rod bodies.

[0017] The advantages and positive effects of this utility model are as follows:

[0018] (1) The heating rod and the rear end cover of the shell are welded to form an integrated heating rod. The weld prevents the leakage of liquid inside the heater, eliminating the need for O-ring rubber seals and improving the sealing reliability of the heater.

[0019] (2) The heating rod welding assembly and the modified control board adopt the conductor lead pin connection, which reduces the TIG welding process and increases the convenience of assembly.

[0020] (3) The improved inlet and outlet pipe end caps adopt a submerged cylindrical structure that fits tightly against the inner surface of the shell. The axial sealing surface has a larger area than the previous radial sealing surface, ensuring reliable sealing. Furthermore, O-ring rubber seals are used for sealing, further enhancing sealing reliability.

[0021] (4) The rubber support sleeve wraps around the front end of the welding integrated part of the heating rod. The rubber support sleeve is supported by the inner wall of the front end of the shell, which is conducive to the locking of the end cap of the water inlet and outlet pipe. It is convenient to assemble. The counter-thrust of the rubber support sleeve is basically absorbed by the inner side of the shell, realizing the optimized setting of the mechanical transmission path, which can further increase the effectiveness of the seal.

[0022] (5) Compared with the existing mechanism, this utility model reduces the number of star-shaped sealing rings at the two front ends and the number of O-rings at the two rear ends while achieving the same function. Furthermore, the two heating rod bodies and the rear end cover of the shell adopt an integrated welding structure, which reduces the number of parts and facilitates assembly.

[0023] (6) The sealing surface area of ​​the improved inlet and outlet pipe end caps has been increased, allowing them to be made of plastic injection molding, which reduces the difficulty of parts manufacturing.

[0024] (7) The front end of the modified outer shell is reinforced with O-ring seals and modified inlet and outlet end caps. Since the O-ring seals are stuck in the ring groove, they have the advantage of being firmly fixed, which is better than the existing sealing effect of using star-shaped seals for end door sealing.

[0025] (8) The modified shell adopts a knife handle-shaped shell that is wide at the front and narrow at the back. It is lightweight and simple in structure, which is superior to the previous square shell. Attached Figure Description

[0026] Figure 1 This is an exploded view of an existing liquid electric heater;

[0027] Figure 2 This is a partial cross-sectional view of the heating rod assembly of an existing liquid electric heater;

[0028] Figure 3 This is a connection and assembly view of the heating rod of an existing liquid electric heater and the modified electronic control board;

[0029] Figure 4 This is an exploded perspective view of the high-sealing resistance wire type high-voltage liquid heater with rear-mounted heating rod of this utility model.

[0030] Figure 5 This is a three-dimensional structural schematic diagram of the welding integrated component of the electric heating rod of this utility model;

[0031] Figure 6 This is a schematic diagram showing the connection between the welded integrated heating rod and the modified electrical control board of this utility model;

[0032] Figure 7 This is an overall sectional view of the present invention: a high-sealing resistance wire type high-voltage liquid heater with a rear-mounted heating rod.

[0033] Figure 8 This is a three-dimensional structural diagram of the modified water outlet end cap of this utility model;

[0034] Figure 9 This is a comparison diagram of the outer shell of an existing liquid electric heater and the liquid electric heater of this utility model;

[0035] Figure 10 This is a partial view of the rear end installation of the welding assembly of the electric heating rod of this utility model;

[0036] Figure 11 This is an overall appearance drawing of a utility model high-voltage liquid heater with a rear-inserted heating rod and high sealing resistance wire. Detailed Implementation

[0037] The structure of this utility model will be further described below with reference to the accompanying drawings and embodiments. It should be noted that these embodiments are descriptive and not limiting.

[0038] Figure 1 This is an exploded view of an existing liquid electric heater, mainly composed of an inlet end cap 1, an outlet end cap (the structure of the outlet end cap is the same as that of the inlet end cap), a front star-shaped sealing ring 2, an O-ring sealing ring 3, connecting screws 4, rubber gaskets 5, two heating rods 6, a square outer shell 7, a rear end cap 8, a rear star-shaped sealing ring 9, a rear cover 10, and a terminal block 11. It also includes a top cover and an electrical control board 12, with the top cover fixedly connected to the upper end of the outer shell, and the electrical control board installed inside the outer shell. The outlet end cap and the top cover are not shown in the attached drawing.

[0039] This utility model relates to a rear-insertion type high-sealing resistance wire high-voltage liquid heater with an electric heating rod. Please refer to [link / reference]. Figures 4-11 The main components include: a modified outer casing 17, a welded heating rod assembly 14, a modified inlet end cap, a modified outlet end cap 15, a rubber support sleeve 13, an O-ring seal 3, a star-shaped seal 16, a rear seal 10, a modified upper cover 19, and a modified electrical control board 18. The shape of the modified upper cover matches the shape of the upper port of the modified outer casing, and the shape of the modified electrical control board matches the inner cavity dimensions of the modified outer casing. The modified inlet end cap and the modified outlet end cap have the same structure.

[0040] The main improvements of this utility model liquid heater compared to existing liquid electric heaters include: the connection form between the heating rod and the rear end cover of the shell is different from the existing structure; the connection form between the conductor lead end of the heating rod and the control board is different from the existing structure; the sealing connection form between the inlet end cover / outlet end cover and the outer shell is different from the existing structure; and the front end limiting method of the heating rod is different from the existing structure.

[0041] The modified outer shell adopts a knife-handle shape, wider at the front and narrower at the rear. An inlet chamber and an outlet chamber are arranged parallel to each other on the left and right sides of the modified outer shell, and the inlet and outlet chambers are connected at the rear. Cylindrical inlet ports 17.1 and 17.2 are respectively located on the left and right sides of the front of the modified outer shell, with threaded holes diagonally provided on the outer sides of the inlet and outlet ports for fixing the modified inlet and outlet end caps. The inlet port is offset to the left side of the inlet chamber and connects to the front end of the inlet chamber. The outlet port is offset to the right side of the outlet chamber and connects to the front end of the outlet chamber. A rear end cap mounting port is provided at the rear of the modified outer shell, corresponding to the inlet and outlet chambers. A sealing ring mounting groove is provided around the rear end cap mounting port for installing a star-shaped sealing ring.

[0042] The heating rod welded assembly 14 includes two heating rod bodies 14.1 and a rear end cover 14.3 of the housing. The heating rod welded assembly 14 achieves metallurgical bonding between the rear ends (conductor lead ends of the heating rods) of the two heating rod bodies and the rear end cover of the housing using laser welding technology. See [link to documentation]. Figure 5The circumferential weld at the insertion part of the heating rod body and the rear end cover of the shell adopts the 0.15mm level penetration control technology to form a continuous and dense sealing interface. Compared with the contact seal that relies on O-rings (made of fluororubber FKM) in the traditional structure, the welding connection between the two heating rods and the rear end cover of the shell achieves three major technological breakthroughs: (1) Upgraded material compatibility, the welding base material can be stainless steel, aluminum alloy and other materials. Traditionally, due to the limitation of high precision machining of the sealing surface, only die-cast aluminum alloy can be selected. (2) Improved sealing reliability after welding, the sealing pressure resistance is increased from 2.5KPa to 1MPa, and the thermal shock resistance is: no leakage after 1000 cold and hot shocks from -40℃ to 150℃. (3) Optimized whole life cycle, eliminating the rubber aging failure mode (the influence of temperature / medium / time), the maintenance cycle of the sample is extended from 3 years / 50,000 kilometers to the same life as the whole vehicle.

[0043] The welded assembly of the heating rods and the modified outer shell are fitted together from back to front. The two heating rod bodies are respectively inserted into the water inlet and water outlet chambers of the modified outer shell. A rubber support sleeve is fitted around the front end of each heating rod body, and the front end of each rubber support sleeve is pressed tightly against the inner wall of the front end of the modified outer shell. The rear end cover of the shell is press-fitted into the rear end cover mounting port of the shell and connected to the rear end of the modified outer shell by multiple screws, forming a sealed fit with a star-shaped sealing ring.

[0044] This utility model's modified inlet and outlet end caps are each composed of a front water pipe section 15.1, a middle flange connection section 15.2, and a rear cylindrical sealing section 15.3. Screw holes are diagonally provided on the middle flange connection section. The modified inlet and outlet end caps are respectively inserted and sealed to the inlet and outlet interfaces on the modified outer shell via their respective rear cylindrical sealing sections. To further improve sealing, an annular groove 15.3.1 is provided on the outer ring of the rear cylindrical sealing section, and an O-ring is embedded in the annular groove. The screw holes on the modified inlet and outlet end caps are aligned with the threaded holes on the outside of the inlet and outlet interfaces, respectively. By inserting screws, the modified inlet and outlet end caps form a fixed, sealed connection with the front end of the modified outer shell.

[0045] The rear-insertion installation method of the aforementioned electric heating rod welded integrated component and the improved sealing connection between the inlet and outlet water pipe end caps and the modified heating shell are improvements made to meet the stringent operating requirements of current new energy vehicle thermal management systems, achieving the following innovations:

[0046] (1) Innovative composite sealing architecture, multi-stage sealing system integration, with the main seal and auxiliary seal working together. The main seal is manifested in the modified inlet / outlet end cap 15 adopting a recessed cylindrical structure that fits tightly against the inner surface of the inlet / outlet interface, see [reference]. Figure 7 The axial sealing area is increased to 2.1 times the original radial sealing area (see...). Figure 2 The requirements for axial surface flatness are reduced to 0.1mm, while the original radial surface flatness requirements are extremely high, making processing difficult. The auxiliary seal is an O-ring 3 (material HNBR, Shore hardness 70±5) in the annular groove 15.3.1 of the modified inlet and outlet pipe end caps, with a compression ratio controlled at 30±2% and a design depth of 6.5mm (width-to-diameter ratio 1.8).

[0047] (2) Reconstruction of the mechanical support system: A rubber support sleeve 13 is used to wrap the end of the welding assembly 14 of the heating rod. The rubber support sleeve 13 is supported by the inner wall surface 17.3 of the front end of the outer shell. See Figure 7 The inner wall surface (axial support surface) at the front end of the outer casing bears a counter-thrust force F=45±5N. In the original heater structure, this counter-thrust force was borne by the inlet and outlet end caps 1. The structural improvement facilitates the locking of the modified inlet and outlet end caps and makes assembly easier. The counter-thrust force F of the rubber support sleeve 13 is almost entirely absorbed by the inner wall surface of the outer casing. The rubber support sleeve 13 uses EPDM rubber to wrap the end of the heating rod 14 360°, which is firmly fixed.

[0048] The control board is fixed above the water inlet and outlet chambers inside the modified housing, and the top cover is fixedly and sealed to the upper end of the modified housing. The heating rod welding assembly 14 and the modified control board 18 adopt an innovative electromechanical integrated connection architecture, realizing a technological upgrade of the electrical connection system. See [link to relevant documentation]. Figure 6 The conductor lead 14.2 of the heating rod welding assembly is connected to the control board using a pin-type connection. Specifically, (1) the end of the conductor lead can be a tapered surface 14.2.1, which is CNC machined to a level of ±0.05mm, with a surface roughness Ra≤0.8μm. The end of the conductor lead can also be designed with a wedge angle of 15°±1° to achieve self-positioning assembly. (2) The connection between the end of the conductor lead and the pin hole on the control board is made using a selective wave soldering process, with the solder joint thickness controlled at 0.15-0.25mm, a peak welding temperature of 245±5℃, and a heat exposure time of <3 seconds.

[0049] The two rear covers are made of insulating material, such as plastic. The two rear covers are fitted onto the rear edge of the two heating rod bodies. The function of the two rear covers is: when the heater is working, the conductor leads are carrying high voltage. The conductor leads 14.2 are close to the rear end cover 14.3 of the shell, so the rear covers are used for insulation to prevent air breakdown during high voltage operation, which would cause the shell to become electrified.

[0050] The advantages of using the above-mentioned pin-type welding connection method between the welded integrated components and the electronic control board are:

[0051] (1) It can eliminate the need for terminal block 11 in the existing heater structure. Figure 3 The process of adding TIG welding is improved, and the contact resistance is reduced from 1.8mΩ to 0.5mΩ, reducing the assembly time by 65% ​​(original process requires 120 seconds → current process requires 42 seconds).

[0052] (2) Compared with the existing connection method between the heating rod and the control board, it has better reliability. The reliability verification is as follows: the contact resistance change is <3% after 50G random vibration and 5000 insertion and removal cycles, and there is no corrosion after 1000h salt spray performance test (ASTM B117).

[0053] The optimized and improved design of the above structure has led to improvements in product performance and technology, including:

[0054] (1) Improved sealing performance, the uniformity of sealing pressure distribution is improved by 40%, the burst pressure is increased from 250KPa to 1MPa, and the structural stability is significantly enhanced.

[0055] (2) Improved assembly efficiency: To achieve the same function, the number of parts has been reduced from 4 to 3, reducing the number of star-shaped sealing rings by 2. The pre-assembly qualification rate of the components has increased from 92% to 99.8%, and the assembly time has been shortened to 45 seconds (the original assembly of this structure required 90 seconds).

[0056] (3) To achieve the same power performance, the improved and optimized outer casing has a smaller volume, see Figure 9 Lightweight and simple in structure, the new knife-handle shaped heater is superior to the previous square heater structure. The novel knife-handle shaped outer shell topology optimization scheme achieves space efficiency optimization, reducing volume by 25% and weight by 20%.

[0057] The above improvements have been achieved: the process pass rate has increased from 83% to 99.6%, making it compatible with fully automated production lines.

[0058] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A high sealing resistance electric resistance wire type high voltage liquid heater of an electric heating rod rear insertion type, characterized by: Including the modified outer shell, the welded integrated heating rod, the modified inlet end cap, the modified outlet end cap, the rubber support sleeve, the star-shaped sealing ring, and the modified electronic control board; The modified outer shell has a water inlet chamber and a water outlet chamber arranged parallel to each other on the left and right sides, and the water inlet chamber and the water outlet chamber are connected at the rear. Cylindrical water inlet interfaces and cylindrical water outlet interfaces are respectively provided at the left and right positions of the front end of the modified outer shell, and threaded holes are provided diagonally on the outside of the water inlet interfaces and the water outlet interfaces. The water inlet interface is offset to the left side of the water inlet chamber and is connected to the front end of the water inlet chamber; the water outlet interface is offset to the right side of the water outlet chamber and is connected to the front end of the water outlet chamber. A rear end cover mounting port is provided at the rear end of the modified outer shell corresponding to the water inlet chamber and the water outlet chamber, and a sealing ring mounting groove is provided around the rear end cover mounting port. The heating rod welding assembly includes two heating rod bodies and a rear end cover of the shell. The rear ends of the two heating rod bodies are inserted and welded to the rear end cover of the shell. The heating rod welding assembly and the modified shell body are inserted from back to front. The two heating rod bodies are respectively inserted into the water inlet cavity and water outlet cavity of the modified shell body. A rubber support sleeve is fitted around the front end of each of the two heating rod bodies. The front ends of the two rubber support sleeves are pressed against the inner wall of the front end of the modified shell body. The rear end cover of the shell body is pressed into the installation port of the rear end cover of the shell body and connected to the rear end of the modified shell body by multiple screws. A star-shaped sealing ring is embedded in the sealing ring installation groove to form a sealing fit. Both the modified inlet end cap and the modified outlet end cap are composed of a front water pipe section, a middle flange connection section, and a rear cylindrical sealing section. Screw holes are diagonally provided on the middle flange connection section. The modified inlet end cap and the modified outlet end cap are respectively inserted and sealed to the inlet and outlet interfaces on the modified outer shell through their respective rear cylindrical sealing sections. The screw holes on the modified inlet end cap and the modified outlet end cap are aligned with the threaded holes on the outside of the inlet and outlet interfaces, respectively. By inserting screws, both the modified inlet end cap and the modified outlet end cap form a fixed, sealed connection with the front end of the modified outer shell. The modified electronic control board is fixed inside the modified outer shell; the conductor lead of the heating rod welding assembly is inserted into the pin hole on the modified electronic control board and welded to the outer ring of the insertion part.

2. The electrically heated rod post-installed high-sealing-resistance resistance wire type high-voltage liquid heater according to claim 1, characterized in that: Both the rear cylindrical sealing part of the modified inlet end cap and the outer ring of the rear cylindrical sealing part of the modified outlet end cap are provided with annular grooves, and O-rings are embedded in the annular grooves.

3. The electrically heated rod post-installed high-sealing-resistance resistance wire type high-voltage liquid heater according to claim 1, characterized in that: The ends of the conductor leads of the heating rod welding assembly are designed with a tapered surface or a wedge-shaped angle.

4. The electrically heated rod post-installed high-sealing-resistance resistance wire type high-voltage liquid heater according to claim 1, characterized in that: It also includes two rear covers, which are fitted onto the rear edge of the two heating rod bodies.

5. The high-sealing resistance wire type high-voltage liquid heater with rear-mounted heating rod according to claim 1, characterized in that: The modified outer shell adopts a knife handle shape with a wide front end and a narrow rear end.

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