阅读说明：本技术 一种温度传感器敏感元件焊接辅助组件及焊接方法 (Welding auxiliary assembly and welding method for sensitive element of temperature sensor ) 是由 张春红 刘伟 薛军 常涛 李智军 党永锋 赵峰刚 于 2021-10-21 设计创作，主要内容包括：本发明涉及温度传感器敏感元件的焊接工艺,具体涉及一种温度传感器敏感元件焊接辅助组件及焊接方法,用于现有液体火箭发动机温度传感器焊接过程存在的热偶丝与壳体焊接难度大、焊接质量不佳的不足之处。该温度传感器敏感元件焊接辅助组件,包括一个用于对壳体待焊端进行旋压塑形的旋压装置,以及一个与所述旋压装置配套使用的散热装置,用于避免两根热偶丝过度熔化,并辅助两根热偶丝与壳体散热。同时,本发明还提供一种温度传感器敏感元件焊接方法。(The invention relates to a welding process of a temperature sensor sensitive element, in particular to a welding auxiliary assembly of the temperature sensor sensitive element and a welding method, which are used for overcoming the defects of high welding difficulty and poor welding quality of a thermocouple wire and a shell in the welding process of the temperature sensor of the traditional liquid rocket engine. The temperature sensor sensitive element welding auxiliary assembly comprises a spinning device and a heat dissipation device, wherein the spinning device is used for spinning and shaping the to-be-welded end of a shell, the heat dissipation device is matched with the spinning device, and the spinning device is used for avoiding excessive melting of two thermocouple wires and assisting the two thermocouple wires to dissipate heat with the shell. Meanwhile, the invention also provides a method for welding the sensitive element of the temperature sensor.)

1. A temperature sensor sensing element welding auxiliary assembly is characterized in that: the spinning device comprises a spinning device (1) for spinning and shaping the end to be welded of a shell (02) and a heat dissipation device (2) matched with the spinning device (1) for avoiding excessive melting of two thermocouple wires (01) and assisting the two thermocouple wires (01) and the shell (02) in heat dissipation;

the spinning device (1) comprises a cylindrical spinning part (11), a connecting part (12) connected with a drilling machine is arranged at the top of the spinning part (11), a spinning hole (111) is formed in the center of the bottom of the spinning part (11), the spinning hole (111) comprises a cylindrical hole (1111) used for accommodating the end parts to be welded of two thermocouple wires (01) and a conical hole (1112) used for spinning the end to be welded of the shell (02), and the maximum diameter of the conical hole (1112) is larger than the diameter of the end to be welded of the shell (02);

heat abstractor (2) comprises two symmetries along the axis symmetry, and heat abstractor (2) inside be provided with be located the axis on and with heat dissipation through-hole (21) of casing (02) adaptation after the spinning, heat dissipation through-hole (21) inner wall and casing (02) outer wall in close contact with, and two thermocouple wires (01) treat that the tip stretches out from heat dissipation through-hole (21) upper end, casing (02) stretch out from heat dissipation through-hole (21) lower extreme, heat abstractor (2) afterbody is provided with clamping part (22) fixed with the workstation.

2. The welding aid for sensitive elements of temperature sensors of claim 1, wherein: the spinning device (1) is made of stainless steel, and the heat dissipation device (2) is made of copper.

3. A method for welding a temperature sensor sensitive element, which comprises the steps of using the temperature sensor sensitive element welding auxiliary assembly as claimed in claim 1 or 2:

step (1): polishing the end parts to be welded of the two thermocouple wires (01), removing the surface oxide film and then wiping the surface oxide film clean;

step (2): the end parts to be welded of the two thermocouple wires (01) penetrate through the shell (02) and extend out of the through hole of the end to be welded of the shell (02), and the two thermocouple wires (01) and the shell (02) are fixed;

and (3): the spinning device (1) is connected with a drilling machine through a connecting part (12), the end to be welded of the shell (02) is spun by the spinning device (1), the end to be welded of the shell (02) is contracted to be conical, and the inner wall of the end to be welded of the shell (02) is in close contact with the side walls of the two thermocouple wires (01);

and (4): fixing a shell (02) in the heat dissipation device (2) to enable the ends to be welded of the two thermocouple wires (01) to extend out of the upper end of the heat dissipation device (2), and enabling the shell (02) to extend out of the lower end of the heat dissipation device (2); then clamping the lower end of the heat dissipation device (2) to enable the inner wall of the lower end of the heat dissipation device (2) to be in close contact with the outer wall of the shell (02);

and (5): the heat dissipation device (2) is fixed on a workbench through a clamping part (22), and the end parts to be welded of the two thermocouple wires (01) and the end parts to be welded of the shell (02) are welded in a TIG welding mode to form a welding ball head.

4. A method for welding a sensitive element of a temperature sensor according to claim 3, characterized in that: in the step (4), the casing (02) is fixed inside the heat dissipation device (2), so that the ends to be welded of the two thermocouple wires (01) extend out of the upper end of the heat dissipation device (2), and the specific implementation mode that the casing (02) extends out of the lower end of the heat dissipation device (2) is as follows: the shell (02) and the heat dissipation device (2) are coaxially located in the heat dissipation through hole (21), the outer wall of the shell (02) is in close contact with the inner wall of the heat dissipation through hole (21), and the lengths of the part, extending out of the heat dissipation device (2), of the two thermocouple wires (01) and the part, extending out of the heat dissipation device (2), of the shell (02) are both larger than 1 mm.

5. The method for welding the sensitive element of the temperature sensor as claimed in claim 4, wherein: and the step (4) also comprises the step of shortening the parts of the two thermocouple wires (01) extending out of the heat dissipation device (2) to enable the lengths of the two thermocouple wires to be 1 mm.

6. The method for welding the sensitive element of the temperature sensor as claimed in claim 5, wherein: in the step (5), the specific implementation mode of welding the end parts to be welded of the two thermocouple wires (01) and the end parts to be welded of the shell (02) by adopting a TIG welding mode is as follows: and setting welding current and welding time, adjusting the position of a welding gun to enable a tungsten electrode to be aligned to the middle parts of the end parts to be welded of the two thermocouple wires (01), starting arc, and carrying out argon arc ignition.

7. The method for welding the sensitive element of the temperature sensor according to any one of the claims 3 to 6, characterized in that: further comprising the step (6): performing quality detection on the welded ball head obtained in the step (5):

(6.1) inspecting the surface quality of the welding spot by adopting a 10-time magnifier, and observing whether defects such as cracks, air holes and the like exist;

(6.2) respectively detecting the tensile strength of the two thermocouple wires (01);

and (6.3) detecting whether the hydraulic strength and the air tightness meet preset requirements.

Technical Field

The invention relates to a welding process of a sensitive element of a temperature sensor, in particular to a welding auxiliary assembly of the sensitive element of the temperature sensor and a welding method.

Background

A large number of temperature sensors of different types are needed in the flying and test run examination process of the liquid rocket engine, and the temperature sensors are installed at different parts of the liquid rocket engine according to needs and used for monitoring temperature data of all parts in the working process of the liquid rocket engine, so that whether the performance of the liquid rocket engine is normal or not is judged.

Welding of a sensitive element is a key process in the production process of the temperature sensor, two thermocouple wires (01) with different material diameters of 0.5mm need to penetrate through the inside of a shell (02) and extend out of a through hole with the aperture of 1.1mm at the end to be welded of the shell (02), and the end to be welded of the two thermocouple wires (01) and the end to be welded of the shell (02) form a welding bulb in a tungsten argon arc welding (TIG) mode, as shown in figure 1, so as to ensure the heat sensitivity and the measurement accuracy of the thermocouple wires. Because the liquid rocket engine has bad working conditions and the temperature sensor needs to be capable of enduring the high working condition requirements of tens of thousands of revolutions per minute, the welding seam of the sensitive element needs to have good anti-vibration and anti-fatigue performances besides the thermocouple wire welding strength tensile test, the welding seam hydraulic strength and the air tightness inspection which meet the design requirements.

According to specific temperature test requirements (high temperature, normal temperature and low temperature environments), different thermocouple wire group material combinations such as nickel-chromium-nickel-silicon, nickel-chromium-constantan, copper-constantan and the like can be selected for the temperature sensors of different types, the material combinations all belong to welding of dissimilar materials, the assembly gap is large, the welding difficulty is large, and the following problems often occur after the conventional TIG welding method is adopted for welding:

(1) the two thermocouple wires are respectively self-melted and cannot be melted with the shell into a whole to form a welding ball head;

(2) the assembly clearance between the side wall of the thermocouple wire and the shell is large, and the shell is very thin, so that the parts to be welded are easy to burn through and collapse, and the products are scrapped;

(3) the tensile strength and the fatigue resistance of the welded product are poor, and the thermocouple wire fracture phenomenon often occurs at a welding spot fusion line in the process of performing a post-welding strength tensile test and working.

Disclosure of Invention

The invention aims to solve the defects of high welding difficulty and poor welding quality of a thermocouple wire and a shell in the welding process of the temperature sensor of the traditional liquid rocket engine, and provides a welding auxiliary assembly and a welding method for a sensitive element of the temperature sensor.

In order to solve the defects of the prior art, the invention provides the following technical solutions:

the welding auxiliary assembly for the sensitive element of the temperature sensor is characterized in that: the device comprises a spinning device for spinning and shaping the end to be welded of the shell and a heat dissipation device matched with the spinning device, and is used for avoiding excessive melting of the two thermocouple wires and assisting the two thermocouple wires to dissipate heat with the shell;

the spinning device comprises a cylindrical spinning part, a connecting part connected with a drilling machine is arranged at the top of the spinning part, a spinning hole is formed in the center of the bottom of the spinning part, the spinning hole comprises a cylindrical hole used for accommodating the end parts to be welded of the two thermocouple wires and a conical hole used for spinning the end to be welded of the shell, and the maximum diameter of the conical hole is larger than the diameter of the end to be welded of the shell;

the heat dissipation device is composed of two symmetrical parts which are symmetrical along an axis, a heat dissipation through hole which is located on the axis and matched with the shell after spinning is arranged inside the heat dissipation device, the inner wall of the heat dissipation through hole is in close contact with the outer wall of the shell, the end portions to be welded of the two thermocouple wires extend out of the upper end of the heat dissipation through hole, the shell extends out of the lower end of the heat dissipation through hole, and a clamping portion which is fixed with the workbench is arranged at the tail of the heat dissipation device.

Further, the spinning device is made of stainless steel, and the heat dissipation device is made of copper.

Meanwhile, the invention also provides a method for welding the sensitive element of the temperature sensor, which is characterized in that the method for welding the auxiliary assembly by adopting the temperature sensor of the liquid rocket engine comprises the following steps:

step (1): polishing the end parts to be welded of the two thermocouple wires, removing the surface oxide film and then wiping the surface oxide film clean;

step (2): the end parts to be welded of the two thermocouple wires penetrate through the shell and extend out of the through hole of the end parts to be welded of the shell, and the two thermocouple wires are fixed with the shell;

and (3): the spinning device is connected with the drilling machine through a connecting part, the to-be-welded end of the shell is spun by the spinning device, so that the to-be-welded end of the shell shrinks to be conical, and the inner wall of the to-be-welded end of the shell is in close contact with the side walls of the two thermocouple wires;

and (4): fixing the shell in the heat dissipation device, so that the end parts to be welded of the two thermocouple wires extend out from the upper end of the heat dissipation device, and the shell extends out from the lower end of the heat dissipation device; then clamping the lower end of the heat dissipation device to make the inner wall of the lower end of the heat dissipation device closely contact with the outer wall of the shell;

and (5): and fixing the heat dissipation device on the workbench through the clamping part, and welding the end parts to be welded of the two thermocouple wires and the end part to be welded of the shell in a TIG (tungsten inert gas) welding mode to form a welding ball head.

Further, in the step (4), the housing is fixed inside the heat dissipation device, so that the ends to be welded of the two thermocouple wires extend out from the upper end of the heat dissipation device, and the specific implementation mode that the housing extends out from the lower end of the heat dissipation device is as follows: the casing and the heat dissipation device are coaxially positioned in the heat dissipation through hole, the outer wall of the casing is in close contact with the inner wall of the heat dissipation through hole, and the length of the part of the two thermocouple wires extending out of the heat dissipation device and the length of the part of the casing extending out of the heat dissipation device are both greater than 1 mm.

Further, the step (4) further comprises the step of shortening the parts of the two thermocouple wires, which extend out of the heat dissipation device, so that the lengths of the two thermocouple wires are 1 mm.

Further, in the step (5), the specific implementation manner of welding the to-be-welded ends of the two thermocouple wires and the to-be-welded end of the housing by using the TIG welding method is as follows: and setting welding current and welding time, adjusting the position of a welding gun to enable a tungsten electrode to be aligned to the middle parts of the end parts to be welded of the two thermocouple wires, starting arc, and carrying out argon arc ignition.

Further, the method also comprises the step (6): performing quality detection on the welded ball head obtained in the step (5):

(6.1) inspecting the surface quality of the welding spot by adopting a 10-time magnifier, and observing whether defects such as cracks, air holes and the like exist;

(6.2) respectively detecting the tensile strength of the two thermocouple wires;

and (6.3) detecting whether the hydraulic strength and the air tightness meet preset requirements.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention adopts the spinning device to accurately control the spinning height of the end to be welded of the shell, effectively reduce and control the assembly clearance between the shell and the thermocouple wire, ensure that the thermocouple wire cannot retract in the welding process and is melted with the shell simultaneously, and avoid the occurrence of poor fusion between welding parts, thereby achieving the purposes of reducing the welding difficulty of the thermocouple wire and the shell and improving the welding quality.

(2) The invention adopts the heat dissipation device to wrap the outer part of the shell, so that the end parts to be welded of the two thermocouple wires keep proper extension length above the heat dissipation device, the thermocouple wires are prevented from being excessively melted, and meanwhile, the outer wall of the shell is tightly attached to the inner wall of the heat dissipation through hole, so that a good heat dissipation effect is obtained, the collapse is prevented, and the purpose of improving the welding quality is achieved.

Drawings

FIG. 1 is a schematic structural diagram of a temperature sensor sensing element suitable for a liquid rocket engine, which is not spun;

FIG. 2 is a schematic structural view of a spinning apparatus according to the present invention;

fig. 3 is a schematic structural diagram of the heat dissipation device of the present invention.

The reference numerals are explained below: 01-thermocouple wire, 02-shell; 1-spinning device, 11-spinning part, 111-spinning hole, 1111-cylindrical hole, 1112-conical hole and 12-connecting part; 2-heat dissipation device, 21-heat dissipation through hole, 22-clamping part.

Detailed Description

The invention will be further described with reference to the drawings and exemplary embodiments.

The structure of the temperature sensor sensitive element before spinning is shown in figure 1, a shell 02 comprises a head cylinder, a middle circular table and a tail cylinder which are sequentially connected, the top end of the head cylinder of the shell 02 is the end to be welded of the shell 02, and the end parts to be welded of two thermocouple wires 01 sequentially penetrate through the tail cylinder and the middle circular table of the shell 02 and extend out of the head cylinder.

Referring to fig. 2 and 3, the welding auxiliary assembly for the sensitive element of the temperature sensor comprises a spinning device 1 for spinning and shaping the to-be-welded end of the shell 02 and a heat dissipation device 2 matched with the spinning device 1 for use, wherein the spinning device 1 is used for preventing the two thermocouple wires 01 from being excessively melted and assisting the two thermocouple wires 01 to dissipate heat with the shell 02.

The spinning device 1 is used for reducing an assembly gap between the side wall of a thermocouple wire 01 and the to-be-welded end of a shell 02 through spinning, is made of stainless steel, and comprises a cylindrical spinning part 11, a connecting part 12 connected with a drilling machine is arranged at the top of the spinning part 11, a limiting step is formed between the connecting part 12 and the spinning part 11, a spinning hole 111 is formed in the bottom of the spinning part 11, and the spinning hole 111 comprises a cylindrical hole 1111 used for accommodating the to-be-welded end parts of the two thermocouple wires 01 and a conical hole 1112 used for spinning the to-be-welded end of the shell 02; after the cylinder at the head of the shell 02 is spun by the spinning device 1, the top end of the cylinder at the head of the shell 02 is contracted into a cone shape.

The heat dissipation device 2 is used for preventing burning-out and burning-through, is processed into an integral structure by adopting a copper material which is easy to dissipate heat, and is cut into two symmetrical parts along the axis direction through the center as shown in figure 3; the inside heat dissipation through-hole 21 that is located the axis and with casing 02 adaptation after the spinning that is provided with of heat abstractor 2, heat dissipation through-hole 21 inner wall and casing 02 outer wall in close contact with, and two thermocouple wires 01 treat that the tip stretches out from heat dissipation through-hole 21 upper end, and casing 02 stretches out from heat dissipation through-hole 21 lower extreme, and 2 afterbody of heat abstractor are provided with the clamping part 22 fixed with the workstation, and the clamping part 22 upper end sets up spacing step.

The invention also provides a method for welding the sensitive element of the temperature sensor, which adopts the liquid rocket engine temperature sensor welding auxiliary assembly and comprises the following steps:

step (1): selecting a part with the length of 20-30 mm at one end of each thermocouple wire 01 as an end part to be welded, polishing the end part to be welded by using metallographic abrasive paper, and wiping the end part to be welded by using absolute ethyl alcohol after removing an oxidized part on the surface;

step (2): the end parts to be welded of the two thermocouple wires 01 penetrate through the shell 02 and extend out of the through hole at the end to be welded of the shell 02, and the two thermocouple wires 01 and the shell 02 are fixed;

and (3): selecting an adaptive spinning device 1 according to the outer diameter size and the structural form of the to-be-welded ends of the shells 02 with different specifications; the spinning device 1 is connected with a drilling machine through a connecting part 12, the to-be-welded end of the shell 02 is spun by the spinning device 1, so that the to-be-welded end of the shell 02 is contracted into a conical shape, and the inner wall of the to-be-welded end of the shell 02 is tightly contacted with the side walls of the two thermocouple wires 01;

and (4): selecting the adaptive heat dissipation device 2 according to the shells 02 with different structural sizes; the shell 02 is fixed inside the heat dissipation device 2 through two symmetrical parts, so that the shell 02 and the heat dissipation device 2 are coaxially positioned in the heat dissipation through hole 21, the outer wall of the shell 02 is tightly contacted with the inner wall of the heat dissipation through hole 21, the end parts to be welded of the two thermocouple wires 01 extend out from the upper end of the heat dissipation device 2, the shell 02 extends out from the lower end of the heat dissipation device 2, and the lengths of the parts of the two thermocouple wires 01 extending out of the heat dissipation device 2 and the parts of the shell 02 extending out of the heat dissipation device 2 are both 2 mm; then, the lower end of the heat dissipation device 2 is clamped by flat tongs, so that the inner wall of the lower end of the heat dissipation device 2 is in close contact with the outer wall of the shell 02; shortening the parts of the two thermocouple wires 01 extending out of the heat dissipation device 2 to enable the lengths of the two thermocouple wires to be 1 mm;

and (5): fixing the heat dissipation device 2 on a workbench through a clamping part 22, setting welding current and welding time according to shells 02 with different structural dimensions and thermocouple wires 01 made of different materials, adjusting the position of a welding gun to enable a tungsten electrode to be aligned to the middle parts of the end parts to be welded of the two thermocouple wires 01, starting an arc, and performing argon arc ignition to form a welding ball head;

and (6): performing quality detection on the welded ball head obtained in the step (5);

(6.1) inspecting the surface quality of the welding spot by adopting a 10-time magnifier, and observing whether defects such as cracks, air holes and the like exist;

(6.2) respectively detecting the tensile strength of the two thermocouple wires 01;

and (6.3) detecting whether the hydraulic strength and the air tightness meet preset requirements.

The above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same, and it is obvious for a person skilled in the art to modify the specific technical solutions described in the foregoing embodiments or to substitute part of the technical features, and these modifications or substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions protected by the present invention.