Temperature regulating device and method for bore surface repair

Abstract

This invention discloses a temperature control device suitable for internal hole surface repair, comprising a temperature acquisition device and a temperature adjustment device. The temperature acquisition device is used to acquire the air temperature in the internal hole region of the workpiece being processed, the nozzle temperature, and the surface temperature of the workpiece. The temperature adjustment device includes a heat exchange jacket and an air pump. One end of the heat exchange jacket is closed, while the other end and the lower side are open. The jacket shell includes a phase change conduction heat exchange layer and a forced convection heat exchange layer, with the phase change conduction heat exchange layer disposed inside the forced convection heat exchange layer. A suction hole is provided on the end wall of the forced convection heat exchange layer located at the open end of the heat exchange jacket, and an air inlet is provided on the opening section of the forced convection heat exchange layer located at the lower opening of the heat exchange jacket. The suction hole is connected to the air pump. This invention can extract dust and control the temperature, thereby improving the quality of workpiece repair.

Description

Technical Field

[0001] This invention belongs to the field of coating reliability processing technology, and particularly relates to a temperature control device and method applicable to the repair of internal hole surfaces. Background Technology

[0002] As an important hydraulic actuator in the mechanical field, hydraulic cylinders are prone to failure due to surface scratches and wear. Statistical results show that, on the one hand, the main failure modes of hydraulic cylinders are surface scratches and wear. On the other hand, the international market for exported hydraulic cylinders has higher requirements for the wear and corrosion resistance of the inner bore surface. However, there is currently a lack of technical means for repairing defects and strengthening the surface of the cylinder bore.

[0003] High-speed laser cladding technology primarily utilizes a high-energy laser beam to simultaneously melt powder and substrate, achieving a metallurgical bond between the two. This results in the fabrication of various high-performance coatings on the surface, offering advantages such as high efficiency, low cost, and a small heat-affected zone. It is suitable for repairing surface defects and enhancing the performance of cylinder-type parts. However, a series of problems still exist in actual processing. On the one hand, due to the relatively narrow and elongated internal space of the cylinder, high temperatures are generated in the molten pool area during cladding, and heat is transferred to the surrounding space through radiation and convection. Prolonged operation will lead to increased temperatures in the internal air and cladding nozzle, affecting the operational stability of optical components, powder feeding, and air supply pipelines within the cladding device. On the other hand, the melting of powder and substrate at high temperatures during cladding generates fumes. Some unmelted powder collides with the substrate at high speed and disperses in all directions. Combined with the narrow and elongated internal space of the cylinder and poor gas flow, the content of suspended particulate matter and fumes in the internal flow area gradually increases. Prolonged operation will lead to severe contamination of the protective lens of the cladding nozzle and an increase in impurities and defects within the coating. The aforementioned challenges prevent the internal cladding process from being carried out continuously for extended periods. In particular, when cladding large areas, intermittent processing will affect the coating quality, reduce processing efficiency, and increase production costs. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a temperature control device and method suitable for repairing the surface of internal holes, which can reduce dust and improve the repair quality during workpiece repair.

[0005] The technical problem to be solved by the present invention is achieved through the following technical solution:

[0006] In a first aspect, a temperature control device suitable for internal hole surface repair is provided, comprising: a temperature acquisition device and a temperature adjustment device; the temperature acquisition device is used to acquire the air temperature in the internal hole region of the workpiece being processed, the nozzle temperature, and the surface temperature of the workpiece being processed; the temperature adjustment device comprises: a heat exchange jacket and an air pump; one end of the heat exchange jacket is closed, and the other end and the lower side are open; the jacket shell of the heat exchange jacket includes a phase change conduction heat exchange layer and a forced convection heat exchange layer, the phase change conduction heat exchange layer being disposed inside the forced convection heat exchange layer; a suction hole is provided on the end wall of the forced convection heat exchange layer located at the open end of the heat exchange jacket, and an air inlet is provided on the opening section of the forced convection heat exchange layer located at the lower opening of the heat exchange jacket; the suction hole is connected to the air pump; the temperature adjustment device adjusts the nozzle temperature and the surface temperature of the workpiece being processed according to the acquired air temperature in the internal hole region of the workpiece being processed, the nozzle temperature, and the surface temperature of the workpiece being processed.

[0007] In conjunction with the first aspect, further, the temperature regulating device adjusts the nozzle temperature and the surface temperature of the workpiece based on the acquired air temperature in the inner bore of the workpiece, the nozzle temperature, and the surface temperature of the workpiece, including:

[0008] The temperature control device adjusts the negative pressure flow rate of the forced convection heat exchange layer based on the obtained air temperature in the inner hole of the workpiece, nozzle temperature, and workpiece surface temperature to regulate the nozzle temperature and workpiece surface temperature.

[0009] In conjunction with the first aspect, the temperature acquisition device further includes: an infrared temperature sensor, a contact temperature sensor, and a non-contact temperature sensor; the infrared temperature sensor is disposed at the open end of the heat exchange jacket for acquiring the surface temperature of the workpiece being processed, the contact temperature sensor is disposed on the nozzle surface for acquiring the nozzle temperature, and the non-contact temperature sensor is disposed on the heat exchange jacket for acquiring the air temperature in the flow area within the inner hole of the workpiece being processed.

[0010] In conjunction with the first aspect, furthermore, the forced convection heat exchange layer has three air inlets on each side of its opening section.

[0011] In addition to the first aspect, each air inlet on the same side is set at equal intervals.

[0012] In conjunction with the first aspect, furthermore, the number of suction holes is two, arranged side by side on the uppermost end wall of the forced convection heat exchange layer.

[0013] Secondly, a temperature control method applicable to the repair of internal hole surfaces includes:

[0014] The temperature control device is set on the outer surface of the cladding device;

[0015] The temperature of the air in the inner hole of the workpiece, the nozzle temperature, and the surface temperature of the workpiece are obtained by a temperature acquisition device.

[0016] Heat from the cladding device is absorbed through the phase change conduction heat exchange layer of the heat exchange jacket;

[0017] The nozzle temperature and the surface temperature of the workpiece being processed are controlled by the forced convection heat exchange layer of the heat exchange jacket absorbing the heat absorbed by the phase change conduction heat exchange layer.

[0018] The forced convection heat exchange layer absorbs the heat absorbed by the phase change conduction heat exchange layer through the negative pressure flow generated by the forced convection heat exchange layer. This negative pressure flow is obtained from the air temperature in the inner hole of the workpiece, the nozzle temperature, and the surface temperature of the workpiece.

[0019] In conjunction with the second aspect, the negative pressure flow rate required for temperature regulation is obtained through equation (1):

[0020]

[0021] Among them, E 激光 E 工件 E 空气 E 喷嘴 E 水冷 These represent the energy generated by the laser per unit time, the energy absorbed by the workpiece, the energy absorbed by the air in the inner bore, the energy absorbed by the nozzle, and the energy absorbed by the water cooling system in the cladding device; c 空气 ρ is the specific heat capacity of the air in the flow region inside the workpiece being processed. 空气 T1 is the air density in the flow domain within the workpiece's inner hole, and T2 is the air temperature in the flow domain within the workpiece's inner hole. 常温 Indicates room temperature.

[0022] In conjunction with the second aspect, thermally conductive silicone grease is further provided between the outer surfaces of the temperature control device and the cladding device.

[0023] In conjunction with the second aspect, the bottom wall thickness of the phase change conduction heat exchange layer is 3 mm.

[0024] The beneficial effects of this invention are as follows: This invention discloses a method and device for controlling the spatial temperature of high-speed laser cladding on the inner surface of cylinder-type parts. Based on a composite dual-circulation system of "forced convection-phase change conduction," the forced convection external circulation achieves cooling and dust removal of the airflow area, while the phase change conduction internal circulation achieves cooling of the nozzle surface and the workpiece, preventing the workpiece temperature from continuously rising. Simultaneously, a real-time temperature-flow self-feedback adjustment system is developed. Based on real-time temperature detection results, it automatically calculates and adjusts the output flow rate of the negative pressure device, achieving precise matching and self-feedback adjustment between temperature and flow rate. This effectively improves the cooling and dust removal efficiency and continuous operation time of the inner hole cladding, and ensures the consistency of the coating forming quality. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the present invention during workpiece processing;

[0026] Figure 2 This is a schematic diagram of the heat exchange to suction hole and air inlet structure in this invention;

[0027] Figure 3 This is a cross-sectional view of the heat exchanger jacket in this invention;

[0028] Figure 4 This is a schematic diagram of the structure of the present invention installed on the cladding device;

[0029] Figure 5 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] To better understand this invention, the relevant technologies in the technical solution of this invention are described below.

[0032] Example 1

[0033] like Figure 1-5 As shown, the present invention provides a temperature control device suitable for repairing the surface of internal holes.

[0034] In this embodiment, the workpiece to be repaired is a hydraulic cylinder. As an important actuator in the field of engineering machinery, the hydraulic cylinder is prone to defects such as scratches, black scale, and dimensional deviations on its inner bore surface during production and processing. During transportation and service, gas-liquid corrosion and wear from hard particles will cause rust and deep groove scratches on the inner bore surface of the cylinder. Compared with traditional processes such as welding and ordinary cladding, high-speed laser cladding has advantages such as low heat input, high processing efficiency, and low cost, and can be widely used for defect repair and performance enhancement of the inner bore surface of cylinders. However, in actual processing, due to the large length-to-diameter ratio, narrow space, and poor gas flow of the cylinder inner bore, severe heat accumulation in the inner bore space and the inability of smoke and dust to diffuse are caused, which in turn affect the service life of optical components, coating forming quality, and continuous operation efficiency.

[0035] The hydraulic cylinder to be repaired is made of 27SiMn material, with an inner diameter of 220mm and an outer diameter of 260mm. It has a cylinder plug at one end and deep groove-like scratches on the inner surface, requiring repair using high-speed laser cladding technology. First, a three-jaw chuck 10 is used to fix one end of the cylinder plug to the turntable, while the other end is placed on the rotary roller 11. During the repair process, the three-jaw chuck 10 drives the cylinder 12 to rotate along its axis. The high-speed laser cladding device is fixed to the front end of the cantilever frame, with the nozzle 9 maintaining a fixed defocus distance from the inner wall of the cylinder 12. The cantilever frame drives the device to feed along its axis. Figure 1 As shown, under the combined action of the rotary motion of cylinder 12 and the feed motion of the cladding device, a cladding coating can be prepared on the inner hole surface to repair defects.

[0036] It includes a temperature acquisition device and a temperature regulation device. The temperature acquisition device includes an infrared temperature sensor 1, a contact temperature sensor 2 and a contact temperature sensor 3, which are used to acquire the air temperature in the inner hole of the workpiece, the nozzle temperature and the surface temperature of the workpiece, respectively.

[0037] The temperature regulating device includes a heat exchange jacket 4 and an air pump 5; one end of the heat exchange jacket 4 is closed, and the other end and the lower side are open; the jacket shell of the heat exchange jacket 4 includes a phase change conduction heat exchange layer 41 and a forced convection heat exchange layer 42, the phase change conduction heat exchange layer 41 is disposed inside the forced convection heat exchange layer 42; two suction holes 43 are provided on the end wall of the forced convection heat exchange layer 42 located at the open end of the heat exchange jacket, arranged side by side, at the forced convection heat exchange layer located at the lower opening of the heat exchange jacket 4. An air inlet 44 is provided on the open section of 42. There are three air inlets on each side section, and the spacing between adjacent air inlets 44 on the same side is equal. The suction hole 43 is connected to the air pump 5. A flow meter is provided on the pipeline between the suction hole 43 and the air pump 5 to calculate the generated negative pressure flow. The temperature adjustment device adjusts the negative pressure flow of the forced convection heat exchange layer according to the obtained air temperature in the inner hole area of ​​the processed workpiece, the nozzle temperature, and the surface temperature of the processed workpiece to adjust the nozzle temperature and the surface temperature of the processed workpiece.

[0038] The temperature acquisition device includes an infrared temperature sensor 6, a contact temperature sensor 7, and a non-contact temperature sensor 8. The infrared temperature sensor 6 is disposed at the open end of the heat exchange jacket 4 to acquire the surface temperature of the workpiece being processed. The contact temperature sensor 7 is disposed on the surface of the nozzle 9 to acquire the temperature of the nozzle 9. The non-contact temperature sensor 8 is disposed on the heat exchange jacket 4 to acquire the air temperature in the inner bore of the workpiece being processed.

[0039] Example 2

[0040] The present invention also provides a temperature control method applicable to the repair of internal hole surfaces, as follows:

[0041] To address the challenges of heat accumulation and dust dispersion during high-speed cladding of inner bore surfaces, this invention employs a combined dual-circulation heat transfer method of "forced convection-phase change conduction." This method utilizes forced convection external circulation to cool and remove dust from the airflow area, and phase change conduction internal circulation to cool the nozzle surface temperature and workpiece surface temperature of the high-speed cladding device.

[0042] This method first collects the surface temperature of the workpiece, the temperature of nozzle 9, and the air temperature in the flow area of ​​the inner hole of the workpiece using a temperature acquisition device.

[0043] The temperatures of the nozzle 9 and the workpiece surface are then adjusted via the phase change heat exchange layer 41 and the forced convection heat exchange layer 42. Both the phase change heat exchange layer 41 and the forced convection heat exchange layer 42 have hollow internal structures. The bottom surface of the phase change heat exchange layer 41 (the contact surface with the cladding device) is a 3mm thick phase change heat pipe wall, while the remaining surfaces are 0.7mm thick metal sheets. Laser welding is used to join the various surfaces together, thus forming an internal cavity. The bottom surface of this device aligns with the outer contour surface of the cladding device and is fixed to the front outer surface of the cladding device, connected in the middle with high thermal conductivity silicone grease.

[0044] When using the temperature control device, the air pump is activated for suction. The phase change heat exchange layer 41 is filled with phase change liquid. The lower half of the phase change heat exchange layer 41 is the evaporation section, and the upper half is the condensation section. During the inner hole cladding process, the phase change liquid in the evaporation section will evaporate and vaporize under high temperature, absorbing heat and drifting upwards. When it reaches the condensation section, the vaporized phase change liquid will liquefy and condense on both sides of the pipe wall, and flow back to the bottom evaporation section under gravity, thus forming an internal circulation inside the phase change heat pipe. At the same time, one side of the phase change heat exchange layer 41 is in contact with the cladding nozzle, and the other side is exposed to forced convection circulation. The heat on the nozzle surface will be transferred from the internal circulation system to the external circulation system, and then discharged from the inner hole flow area under forced convection. Thus, heat transfer is achieved under the combined dual circulation of "forced convection-phase change conduction", which can effectively solve the problems of heat accumulation and dust dispersion during inner hole cladding. The dust generated during the cladding process can be sucked away from the air inlet 44.

[0045] In order to effectively and accurately control the temperature of nozzle 9 (made of brass) and the workpiece surface, we need to calculate the negative pressure flow rate, as follows:

[0046] When the substrate material is 27SiMn and the powder material is 316L, the high-speed laser cladding process parameters are as follows: laser power 4000W, spot diameter 4mm, cladding linear speed 10m / min, overlap rate 50%, cladding forward movement speed 1.74m / h, coating thickness 0.6mm, and the cladding nozzle is cylindrical with a diameter of 50mm. During stable operation, since the airflow and nozzle surface temperatures stabilize after reaching a certain value, fluctuations are negligible. At this point, E can be considered... 空气 E 喷嘴 All values ​​are zero, and the laser output energy per unit time is 1.5 × 10⁻⁶. 8 J will be converted into the sum of heat removed by the workpiece heating, water cooling system, and temperature control device. The nozzle water cooling system uses a flow rate of 5 m³ / h and an inlet / outlet water temperature difference of 6.8℃. The surface temperature difference of the workpiece before and after cladding is 1200℃, and the inlet / outlet air temperature difference of the temperature control device is 100℃. Regarding the specific heat capacity and density of common materials, air has a specific heat capacity of 1000 J / (kg·℃) and a density of 1.29 kg / m³. 3 Water has a specific heat capacity of 4200 J / (kg·℃) and a density of 1000 kg / m³. 3 The specific heat capacity of 27SiMn steel is 460 J / (kg·℃), and its density is 7900 kg / m³. 3 Brass has a specific heat capacity of 390 J / (kg·℃) and a density of 8600 kg / m³. 3 Substituting the magnitude of the negative pressure flow rate, it can be expressed as:

[0047]

[0048] When laser parameters become abnormal, the laser output energy per unit time decreases from 1.5 × 10⁻⁶. 8 J becomes 1.7 × 10 8 J will cause the temperatures of the workpiece, air, and nozzle to rise. At this time, the temperature difference between the inlet and outlet of the nozzle water cooling system is 7.4℃, the surface temperature difference of the workpiece before and after cladding is 1400℃, the air temperature difference between the inlet and outlet of the temperature regulating device is 120℃, and the surface temperature difference of the nozzle is 300℃. Then the magnitude of the negative pressure flow rate is:

[0049]

[0050] Among them, E 激光 E 工件 E 空气 E 喷嘴 E 水冷 These represent the energy generated by the laser per unit time, the energy absorbed by the workpiece, the energy absorbed by the air in the inner bore, the energy absorbed by the nozzle, and the energy absorbed by the water cooling system in the cladding device; c 空气 ρ is the specific heat capacity of the air in the flow region inside the workpiece being processed. 空气T1 is the air density in the flow domain within the workpiece's inner hole, and T2 is the air temperature in the flow domain within the workpiece's inner hole. 常温 This represents room temperature; the laser temperature, workpiece temperature, air temperature in the internal flow area, nozzle temperature, and water cooling system temperature can all be directly obtained. Therefore, the energy per unit time can be determined from the temperature. Thus, E 激光 E 工件 E 空气 E 喷嘴 E 水冷 As a known quantity, the control module substitutes the data collected by the temperature sensor into the calculation formula to determine that the negative pressure flow rate matching the abnormal temperature is 11.2 m³ / s. 3 The system transmits the numerical signal at a rate of / h to air pump 5, which automatically increases motor power and speed to enhance negative pressure flow output. It also uses a temperature control device to dissipate abnormal heat from the inner orifice. As the inner orifice temperature gradually stabilizes at normal levels, the negative pressure flow rate gradually decreases with temperature changes, from 11.2 m³ / h. 3 The system gradually adjusts itself to 7.1m using feedback. 3 / h, until stable operation is restored.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A temperature control device suitable for repairing the surface of internal holes, characterized in that, The system includes a temperature acquisition device and a temperature regulation device. The temperature acquisition device is used to acquire the air temperature in the flow area of ​​the inner hole of the workpiece being processed, the nozzle temperature, and the surface temperature of the workpiece. The temperature regulation device includes a heat exchange jacket and an air pump. One end of the heat exchange jacket is closed, while the other end and the lower side are open. The jacket shell includes a phase change heat exchange layer and a forced convection heat exchange layer, with the phase change heat exchange layer disposed inside the forced convection heat exchange layer. A suction hole is provided on the end wall of the forced convection heat exchange layer located at the open end of the heat exchange jacket, and an air inlet is provided on the opening section of the forced convection heat exchange layer located at the lower opening of the heat exchange jacket. The suction hole is connected to the air pump. The temperature regulation device adjusts the nozzle temperature and the surface temperature of the workpiece being processed based on the acquired air temperature in the flow area of ​​the inner hole of the workpiece, the nozzle temperature, and the surface temperature of the workpiece.

2. The temperature control device for repairing internal hole surfaces according to claim 1, characterized in that, The temperature control device adjusts the nozzle temperature and the workpiece surface temperature based on the obtained air temperature in the inner bore of the workpiece, the nozzle temperature, and the workpiece surface temperature, including: The temperature control device adjusts the negative pressure flow rate of the forced convection heat exchange layer based on the obtained air temperature in the inner hole of the workpiece, nozzle temperature, and workpiece surface temperature to regulate the nozzle temperature and workpiece surface temperature.

3. The temperature control device for repairing internal hole surfaces according to claim 1, characterized in that, The temperature acquisition device includes an infrared temperature sensor, a contact temperature sensor, and a non-contact temperature sensor. The infrared temperature sensor is disposed at the open end of the heat exchange jacket to acquire the surface temperature of the workpiece being processed. The contact temperature sensor is disposed on the surface of the nozzle to acquire the nozzle temperature. The non-contact temperature sensor is disposed on the heat exchange jacket to acquire the air temperature in the flow area inside the workpiece being processed.

4. The temperature control device for internal hole surface repair according to claim 1, characterized in that, The forced convection heat exchange layer has three air inlets on each side of its open section.

5. A temperature control device for repairing internal hole surfaces according to claim 1, characterized in that, Each air inlet on the same side is spaced at equal intervals.

6. A temperature control device for repairing internal hole surfaces according to claim 1, characterized in that, The number of suction holes is two, which are arranged side by side on the uppermost end wall of the forced convection heat exchange layer.

7. A method for temperature control of applicable internal hole surface repair using the temperature control device for applicable internal hole surface repair according to any one of claims 1 to 6, characterized in that, include: The temperature control device is set on the outer surface of the cladding device; The temperature of the air in the inner hole of the workpiece, the nozzle temperature, and the surface temperature of the workpiece are obtained by a temperature acquisition device. Heat from the cladding device is absorbed through the phase change conduction heat exchange layer of the heat exchange jacket; The nozzle temperature and the surface temperature of the workpiece being processed are controlled by the forced convection heat exchange layer of the heat exchange jacket absorbing the heat absorbed by the phase change conduction heat exchange layer. The forced convection heat exchange layer absorbs the heat absorbed by the phase change conduction heat exchange layer through the negative pressure flow generated by the forced convection heat exchange layer. This negative pressure flow is obtained from the air temperature in the inner hole of the workpiece, the nozzle temperature, and the surface temperature of the workpiece.

8. The temperature control method for repairing internal hole surfaces according to claim 7, characterized in that, The negative pressure flow rate required to regulate the temperature is obtained by equation (1): （1） in, , , , , These represent the energy generated by the laser per unit time, the energy absorbed by the workpiece, the energy absorbed by the air in the inner bore flow area, the energy absorbed by the nozzle, and the energy absorbed by the water cooling system in the cladding device; This refers to the specific heat capacity of the air in the flow region within the inner hole of the workpiece being processed. The air density in the flow area within the inner hole of the workpiece being processed. The air temperature in the flow area within the inner hole of the workpiece being processed. Indicates room temperature.

9. A temperature control method for repairing internal hole surfaces according to claim 6, characterized in that, Thermally conductive silicone grease is applied between the outer surfaces of the temperature control device and the cladding device.

10. A temperature control method for repairing internal hole surfaces according to claim 6, characterized in that, The bottom wall thickness of the phase change conductive heat exchange layer is 3mm.

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