A process for machining a sensor housing

Abstract

This invention relates to a process for processing a sensor housing. The process includes: Step 1: Processing finished bushings, finished sensor elements, and a pressure head according to the required dimensions; Step 2: Machining the inner hole of the bushing mounting area to the dimensions shown in the drawing, leaving machining allowance for the remaining parts; Step 3: Applying pressure to the large end of the pressure head using a press to press the bushing into the inner hole of the housing; Step 4: Machining the inner hole of the pressed housing assembly to the final dimensions; Step 5: Welding the sensor element and the housing together using laser welding equipment, and conducting a sealing test on the weld; Step 6: Performing magnetic annealing on the housing assembly; Step 7: Using a lathe to further machine the housing assembly, machining the outer wall of the housing to the final dimensions; Step 8: Using a passivation solution to clean the outer surface of the housing, forming an oxide film on the surface. Housing assemblies processed using this method have accurate dimensions, good welding sealing and corrosion resistance, and a high product qualification rate.

Description

Technical Field

[0001] This invention relates to the field of sensor housing processing technology, and in particular to a process method for processing sensor housings. Background Technology

[0002] Sensors are increasingly widely used in fields such as aerospace products. Many existing sensors are typically composed of a housing, an internal sensing element, and a control circuit. In addition to housing the sensor, the housing is more importantly used to protect the internal components to ensure the accuracy and reliability of the sensor during use. In the production and processing of some sensors, the housing has high quality requirements, and the processing of sensor housings needs to be formulated in accordance with production processes. Summary of the Invention

[0003] To address the problems mentioned in the background section, this invention provides a process for manufacturing a sensor housing.

[0004] This invention discloses the following technical solution: a process for processing a sensor housing, comprising a pressure head fixture, the pressure head being a multi-segment cylindrical structure, the small end of the pressure head being able to mate with the inner diameter of a bushing, and a pressure press applying pressure to the large end of the pressure head to install the bushing into the inner hole of the housing. The specific processing method is as follows:

[0005] Step 1: Machining the bushing, induction plate, and pressure head. According to the size requirements of the bushing and pressure head, use a lathe to machine the finished bushing, induction plate, and pressure head.

[0006] Step 2: Rough machining of the outer shell. Use a lathe to machine the inner hole and outer wall of the outer shell. Machin the inner hole at the bushing mounting location to the dimensions shown in the drawing, and leave machining allowance for the rest.

[0007] Step 3: Bushing pressing. The inner hole of the bushing is assembled with the small end of the press head. The upper end face of the bushing abuts against the end face of the step above the small end of the press head. The rough-machined outer shell is placed vertically on the press table with the bushing mounting hole facing upward. The press head and bushing are vertically inserted into the inner hole of the outer shell. The press head is used to apply pressure to the large end of the press head to press the bushing into the inner hole of the outer shell. Then the press head is removed.

[0008] Step 4: Boring the inner hole of the outer shell, machining the inner hole of the press-fitted outer shell to the final size.

[0009] Step 5: Laser welding. The sensor is installed into the φ10mm inner hole of the outer shell, with the inner end face flat. The sensor and the outer shell are welded together using laser welding equipment to obtain the outer shell assembly. A sealing test is then performed on the outer shell assembly by inputting 0.6MP of air pressure into the inner cavity of the outer shell assembly and maintaining it for more than 1 minute.

[0010] Step Six: Magnetic Annealing. Heat the outer casing assembly to 1150℃ in a vacuum environment, hold for 2 hours, and then allow it to cool naturally to room temperature.

[0011] Step 7: Finishing the outer casing. Use a lathe to machine the outer casing components, machining the outer wall of the casing to the final dimensions, and inspecting each machined dimension and sealing performance.

[0012] Step 8: Surface passivation treatment. Use passivation solution to wipe the outer surface of the housing component to form an oxide film on the surface of the housing component.

[0013] Furthermore, in step two, the outer wall thickness of the outer shell is left with a finishing allowance of 0.5mm.

[0014] Furthermore, in steps two, four, and seven, when finishing the outer casing assembly, the preferred cutting speed is (50-100) m / min, the cutting depth is controlled at (0.1-0.3) mm, and the feed rate is no more than 1 mm / r.

[0015] Furthermore, the vacuum environment in step six is ​​preferably (5-10) Pa.

[0016] Furthermore, in step eight, the passivation solution is prepared as follows: 5% nitric acid and 95% water. After wiping, keep it for 1 hour and then rinse with water.

[0017] Furthermore, the press in step three is a manual press.

[0018] Beneficial effects: Compared with the prior art, the sensor housing processing method of the present invention has a reasonable process arrangement, accurate dimensions of the processed housing components, good welding sealing, good corrosion resistance of the housing components, meets the design requirements of the drawings, and has a high product qualification rate. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the sensor housing assembly structure of the present invention;

[0020] Figure 2 This is a schematic diagram of the pressure head structure of the present invention;

[0021] Figure 3 This is a schematic diagram of the bushing press-fitting of the present invention;

[0022] In the diagram: 1-outer shell, 2-shield, 3-sensor plate, 4-pressure head. Detailed Implementation

[0023] like Figure 1As shown, the sensor housing assembly consists of a housing 1, a bushing 2, and a sensing element 3. The housing 1 and the sensing element 3 are made of austenitic stainless steel 1Cr18Ni9Ti, and the bushing 2 is made of iron-nickel-based soft magnetic alloy 1J79. The austenitic stainless steel 1Cr18Ni9Ti has excellent corrosion resistance, and the iron-nickel-based soft magnetic alloy 1J79 is a magnetic material. After machining, it should be magnetically annealed to reduce coercivity. The bushing 2 has an outer diameter of φ13.5mm and an inner diameter of φ10mm. The bushing 2 is installed in the inner hole of the housing 1 with a diameter of φ13.5mm and a wall thickness of 0.5mm. The sensing element 3 is welded to the inner hole of the housing 1 with a diameter of φ13.5mm. The upper end face of the sensing element 3 abuts against the bushing 2, and the lower end face of the sensing element 3 is flush with the lower end face of the housing 1.

[0024] like Figures 2 to 3 As shown, the pressure head 4 is a cylindrical structure with multiple diameters. The smallest outer diameter is φ10mm and the length is 20mm. The middle outer diameter is φ13.4mm. The lower end of the outer diameter φ10mm is provided with a radius of R1.

[0025] A process for machining a sensor housing 1 includes a pressure head 4, which is a multi-section cylindrical structure. The small end of the pressure head 4 can be fitted with the inner diameter of a bushing 2. Pressure is applied to the large end of the pressure head 4 using a press to install the bushing 2 into the inner hole of the housing 1. The specific machining process is as follows:

[0026] Step 1: Machining bushing 2, sensor plate 3 and pressure head 4. According to the size requirements of bushing 2 and pressure head 4, use machining to process the finished bushing 2, sensor plate 3 and pressure head 4.

[0027] Step 2: Rough machining of outer shell 1. Use a lathe to machine the inner hole and outer wall of outer shell 1. Machin the inner hole of bushing 2 to the dimensions shown in the drawing. Leave a finishing allowance for the rest to ensure the wall thickness at the bushing 2 mounting hole and prevent machining deformation.

[0028] Step 3: Pressing the bushing 2. The inner hole of the bushing 2 is assembled with the outer diameter of the press head 4 at φ10mm. The upper end face of the bushing 2 abuts against the end face of the step between the outer diameters of the press head 4 at φ10mm and φ13.4mm. The rough-machined outer shell 1 is placed vertically on the press table with the bushing 2 mounting hole facing upward. The press head 4 and the bushing 2 are vertically inserted into the inner hole of the outer shell 1. The press head 4 is used to apply pressure to the large end of the press head 4 to press the bushing 2 into the inner hole of the outer shell 1. Then the press head 4 is removed. Using the press head 4 to press the bushing 2 can prevent the bushing 2 and the outer shell 1 from deforming.

[0029] Step 4: Boring the inner hole of the outer shell 1, and machining the inner hole of the press-fitted outer shell 1 to the final size.

[0030] Step 5: Laser welding. The sensor 3 is installed into the φ10mm inner hole of the outer shell 1 with its outer end face flush. The sensor 3 and the outer shell 1 are welded together using laser welding equipment to form an outer shell assembly. A sealing test is performed on the weld seam by inputting 0.6MP of air pressure into the inner cavity of the outer shell assembly and maintaining it for more than 1 minute without leakage.

[0031] Step Six: Magnetic Annealing. Heat the outer shell assembly to 1150℃ in a vacuum environment, hold for 2 hours, and allow it to cool naturally to room temperature. This reduces the coercivity generated during the processing of bushing 2 and removes the stress generated during laser welding.

[0032] Step 7: Finish machining of outer shell 1. Use a lathe to machine outer shell 1 to the final size. Inspect all machined dimensions to ensure that the outer diameter, surface roughness, etc. meet the requirements of the drawing.

[0033] Step 8: Surface passivation treatment. Use passivation solution to wipe the outer surface of the housing components to form an oxide film on the surface of the housing components, thereby improving corrosion resistance.

[0034] In step two, a finishing allowance of 0.5mm is left for the outer wall thickness of the outer shell 1. After rough machining, the wall thickness of the hole at the bushing 2 mounting location on the outer shell 1 is 1.3mm to prevent deformation during the press-fitting of the bushing 2. During steps two, four, and seven, when machining the outer shell 1, due to the high hardness of the material, the preferred cutting speed is (50-100) m / min, the cutting depth is controlled at (0.1-0.3) mm, and the feed rate is no more than 1mm / r to ensure surface quality. The preferred vacuum environment in step six is ​​(5-10) Pa. In step eight, the passivation solution ratio is: 5% nitric acid and 95% water. After wiping, keep it for 1 hour and then rinse with water to ensure the formation of an oxide film on the surface of the outer shell assembly. A manual press can be used in step three, allowing operators to easily observe and control the force when pressing the bushing 2. The outer shell assembly processed using the above methods has accurate dimensions, good welding sealing and corrosion resistance, meets the design requirements, and has a high product qualification rate.

[0035] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A process for manufacturing a sensor housing, characterized in that: Includes a pressure head, which is a multi-section cylindrical structure. The small end of the pressure head can be fitted with the inner diameter of the bushing. A pressure press is used to apply pressure to the large end of the pressure head to install the bushing into the inner hole of the outer shell. The specific processing method is as follows: Step 1: Machining the bushing, induction plate, and pressure head. According to the size requirements of the bushing and pressure head, use machining methods to produce the finished bushing, induction plate, and pressure head. Step 2: Rough machining of the outer shell. Use a lathe to machine the inner hole and outer wall of the outer shell. Machin the inner hole at the bushing mounting location to the dimensions shown in the drawing. Leave a finishing allowance for the remaining parts. Step 3: Bushing pressing. The inner hole of the bushing fits with the small end of the press head, and the upper end face of the bushing abuts against the end face of the step above the small end of the press head to ensure that the bushing is pressed without twisting or deformation. The rough-machined outer shell is placed vertically on the press table with the bushing mounting hole facing upward. The press head and bushing are vertically inserted into the inner hole of the outer shell. The press head is used to apply pressure to the large end of the press head to press the bushing into the inner hole of the outer shell, and then the press head is removed. Step 4: Boring the inner hole of the outer shell, machining the inner hole of the press-fitted outer shell to the final size; Step 5: Laser welding. The sensor is installed into the φ10mm inner hole of the outer shell, with the outer end face flush. The sensor and the outer shell are welded together using laser welding equipment to obtain the outer shell assembly. A sealing test is then performed on the weld. Step 6: Magnetic annealing, heat to 1150℃ in a vacuum environment, hold for 2 hours, and then cool naturally to room temperature; Step 7: Finishing the outer casing. Use a lathe to machine the outer casing components, machining the outer wall to the final dimensions, and checking all machined dimensions and sealing performance. Step 8: Surface passivation treatment. Use passivation solution to wipe the outer surface of the shell to form an oxide film on the shell surface.

2. The process method for processing the sensor housing according to claim 1, characterized in that: In step two, the machining allowance for the outer wall thickness of the outer shell is 0.5mm, and the machining allowance for the end face of the sensing end is 0.1mm.

3. The process method for processing the sensor housing according to claim 1, characterized in that: For steps two, four, and seven, when finishing the outer shell, the cutting speed is (50-100) m / min, the cutting depth is controlled at (0.1-0.3) mm, the feed rate is not greater than 1 mm / r, and the cooling method is to select emulsion or sulfurized oil cutting fluid.

4. The process method for processing the sensor housing according to claim 1, characterized in that: The vacuum environment in step six is ​​(5-10) Pa.

5. The process method for processing the sensor housing according to claim 1, characterized in that: In step eight, the passivation solution is prepared as follows: 5% nitric acid and 95% water. After wiping, keep it for 1 hour and then rinse with water.

6. The process method for processing the sensor housing according to claim 1, characterized in that: The press in step three is a manual press.

7. The process method for processing the sensor housing according to claim 1, characterized in that: The sealing test in step five involves inputting 0.6 MPa of air pressure into the inner cavity of the outer shell and maintaining it for more than 1 minute.

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