CN115046016A

CN115046016A - Expansion valve

Info

Publication number: CN115046016A
Application number: CN202210220355.6A
Authority: CN
Inventors: D·尼克; M·阿诺德
Original assignee: MinebeaMitsumi Inc
Current assignee: MinebeaMitsumi Inc
Priority date: 2021-03-08
Filing date: 2022-03-08
Publication date: 2022-09-13
Also published as: DE102021105506A1

Abstract

The invention relates to an expansion valve having a pressure vessel (12) for partially accommodating a linear actuator (14), a valve block (16) and an adapter (18) for connecting the pressure vessel (12) to the valve block (16), wherein the pressure vessel (12) is at least partially inserted into the adapter (18) and a welding lip (22) of the adapter (18) surrounds a wall (24) of the pressure vessel (12) in the circumferential direction in a base region (26) of the pressure vessel (12). According to the invention, the pressure vessel (12) is connected to the adapter (18) by means of a circumferential weld seam (20), wherein the seam thickness (28) of the weld seam (20) at least substantially corresponds to the wall thickness (30) of the wall (24) of the pressure vessel (12).

Description

Expansion valve

Technical Field

The present invention relates to an expansion valve.

Background

Expansion valves having a pressure vessel for partially accommodating a linear actuator (german), a valve block and an adapter for connecting the pressure vessel to the valve block are known from the prior art. In the expansion valves of the prior art, the pressure vessel is inserted into an adapter, wherein the welding lip of the adapter surrounds the wall of the pressure vessel in the circumferential direction in the bottom region of the pressure vessel. The pressure vessel is connected to the adapter by means of a circumferential weld seam. In the expansion valve of the prior art, the wall of the pressure vessel and the welding lip of the adapter have the same wall thickness. The stability of the weld seam is decisively dependent on the seam thickness of the weld seam, which is always smaller than the wall thickness of the counterpart to be welded itself, given the same wall thickness of the counterpart to be welded.

Disclosure of Invention

The object of the invention is to provide an expansion valve (german) which has advantageous properties with regard to the stability of the weld connecting the pressure vessel to the Adapter. This object is achieved by the features of the invention. Preferred embodiments of the invention are given in the dependent claims.

The invention relates to an expansion valve having a pressure vessel (Druckkapsel) for partially accommodating a linear actuator, a valve block and an adapter for connecting the pressure vessel to the valve block, wherein a base region of the pressure vessel is at least partially inserted into the adapter, a welding lip of the adapter surrounds a wall of the pressure vessel in the circumferential direction in the base region of the pressure vessel, and the pressure vessel is connected to the adapter by means of a circumferential weld seam.

The invention proposes that the seam thickness of the weld seam corresponds at least substantially to the wall thickness of the wall of the pressure vessel.

The expansion valve is in particular provided for controlling and/or regulating the fluid flow in the fluid channel. "provided" is to be understood in particular to mean specially programmed, designed and/or equipped. An "object is provided for a specific function" is intended to mean, in particular, that the object fulfills and/or performs this specific function in at least one operating state and/or operating state. The expansion valve is in particular designed as a needle valve. A "needle valve" is to be understood to mean, in particular, a valve having a, in particular, needle-shaped valve piston which can be moved linearly in a valve seat of the needle valve in order to increase and/or decrease a flow opening of a fluid channel. The fluid passage extends in particular through a valve block of the expansion valve. In particular, a linear actuator is provided in the needle valve, in particular, for causing a linear movement of a valve piston of the needle valve. The shaft of the linear actuator is coupled in particular to the valve piston of the needle valve. A "fluid flow" is to be understood in this context, in particular, as a liquid flow, a gas flow and/or a combination thereof. The needle valve can be provided in particular for influencing a fluid flow, in particular a coolant flow, in a motor vehicle. The expansion valve can be provided in particular for controlling and/or regulating a coolant flow in an air conditioning cycle of an air conditioning system, in particular of a motor vehicle air conditioning system.

In addition to the linear actuator, the expansion valve also has a fluid-tight pressure vessel, inside which the shaft of the linear actuator and the rotor of the electric motor of the linear actuator are arranged. The rotor of the electric motor is arranged on the shaft, in particular, in a rotationally fixed manner. In particular, the stator of the electric motor of the linear actuator is arranged on the outside of the pressure vessel and completely surrounds the rotor of the electric motor and the pressure vessel in the circumferential direction. The rotor of the electric motor, the pressure vessel and the stator of the electric motor are arranged at least substantially coaxially with respect to each other. The outer wall of the pressure vessel is located in the working air gap between the rotor and the stator of the motor. The control unit of the linear actuator and/or the needle valve is arranged outside the pressure vessel. In particular, the expansion valve comprises a housing in which the linear actuator, the pressure vessel and the control unit are arranged.

The shaft of the linear actuator is rotatably mounted by means of a ball bearing on a first end of the shaft, which is in particular the valve piston facing the needle valve. In particular, the inner ring of the ball bearing is pressed onto the first end of the shaft or the first end of the shaft is pressed into the inner ring of the ball bearing. In particular, the outer ring of the ball bearing can be accommodated in the associated bearing seat in the expansion valve with a clearance fit. In order to support a second end of the shaft, which is axially opposite to the first end of the shaft, the linear actuator comprises a plain bearing unit. The plain bearing unit has a bearing body in which the second end of the shaft is slidably supported. The bearing body is at least substantially made of plastic and/or fiber-reinforced plastic. The bearing body has an at least substantially cylindrical bearing recess for receiving the second end of the shaft. Alternatively, the bearing recess may have three inner surfaces which are arranged at an angle of at least approximately 60 ° to one another and which bear tangentially at the second end of the shaft. The inner geometry of the bearing recess of the bearing body at least substantially corresponds to the outer geometry of the second end of the shaft. The second end of the shaft is guided in a bearing recess of the bearing body, in particular in a clearance fit.

In order to connect the pressure vessel and the part of the linear actuator arranged in the pressure vessel with the valve block, the expansion valve has an adapter. In order to establish a connection between the pressure vessel and the valve block, the adapter has an external thread for screwing into a corresponding internal thread of the valve block. A ball bearing for supporting the first end of the shaft of the linear actuator is arranged in particular inside the adapter. The pressure vessel is preferably connected to the adapter by means of a circumferential weld seam. The weld seam is formed in particular by means of laser welding. The pressure vessel and the adapter are arranged in particular at an overlap joint, and the weld seam is in particular configured as a fillet weld seam (german: Kehlnaht). The fillet weld can be designed in particular as an isosceles fillet weld (German: gleichschenklige Kehlnaht). The weld must be particularly pressure-resistant and gas-tight. Furthermore, the weld must meet the requirements in terms of resistance to rupture strength and/or load alternation pressure resistance during operation of the expansion valve. For this purpose, the respective wall thickness or wall thickness ratio is designed in particular for the adapter and the pressure vessel in such a way that, during welding, a circumferential weld seam is formed, the seam thickness (theoretical thickness) of which corresponds at least substantially to the wall thickness of the pressure vessel wall. The seam thickness of the weld seam corresponds at least substantially to the wall thickness of the pressure vessel wall, in this context it being understood in particular that the seam thickness of the weld seam deviates at most 30%, preferably at most 20% and particularly preferably at most 10% from the wall thickness of the pressure vessel. For a fillet weld, the joint thickness corresponds to the height of the drawable triangle measured up to the theoretical root point of the fillet weld.

This embodiment makes it possible to provide an expansion valve with advantageous properties with regard to the stability of the weld connecting the pressure vessel to the adapter. In particular, advantageous compressive strengths, in particular the rupture strength and the compressive load change strength, can be achieved by the design of the weld seam.

Furthermore, it is proposed that the wall thickness of the welding lip of the adapter in the region of the weld seam is greater than the wall thickness of the wall of the pressure vessel. This advantageously makes it possible to provide a weld seam that is safe to handle and can be processed with more material. Since the wall of the pressure vessel is arranged in the air gap between the rotor and the stator of the electric motor of the linear actuator of the expansion valve, the maximum wall thickness of the wall of the pressure vessel is limited by the maximum possible size of the air gap and thus by the maximum available installation space. Thus, with regard to the way in which additional material is provided for producing a process-safe and machinable weld seam, the wall thickness of the welding lip of the adapter in the region of the weld seam can only be increased relative to the wall thickness of the wall of the pressure vessel. In a preferred embodiment of the invention, the wall thickness of the welding lip of the adapter in the region of the weld seam is 10% to 40% greater than the wall thickness of the wall of the pressure vessel. Preferably, the wall of the pressure vessel has a wall thickness of 0.7mm, while the welding lip of the adapter has a wall thickness between 0.77mm and 1.0mm in the region of the weld seam.

The different wall thicknesses of the walls of the pressure vessel and the adapter result in stress concentrations and/or notch effects. In order to counteract this and to achieve a uniform stress distribution, it is furthermore proposed that the welding lip of the adapter has a circumferential material thinning in the region spaced apart from the weld seam (german: materialverhungung). Preferably, the minimum wall thickness of the welding lip of the adapter at least substantially corresponds to the wall thickness of the wall of the pressure vessel in the region of the material thinning. The minimum wall thickness of the welding lip of the adapter at least substantially corresponds to the wall thickness of the pressure vessel wall in the region of the material weakening, in which context it is to be understood in particular that the minimum wall thickness of the welding lip of the adapter differs from the wall thickness of the pressure vessel in the region of the material weakening within the scope of manufacturing tolerances. Furthermore, an advantageously compact design can be achieved by the material thinning, as a result of which further design features can be formed.

Furthermore, the invention relates to an adapter for an expansion valve according to the invention. The invention proposes that the welding lip of the adapter has a circumferential material thinning in a region spaced apart from the weld seam. This advantageously makes it possible to provide more material for a weld seam that is safe in terms of production and can be processed when welding the adapter to the pressure vessel.

The expansion valve according to the invention should here not be limited to the applications and embodiments described above. In particular, the expansion valve according to the invention may have a different number of individual elements, members and units than those described herein in order to achieve the mode of action described herein.

Drawings

Other advantages are illustrated in the following figures. An embodiment of the invention is shown in the drawings. The figures, description and claims contain a large number of combined features. The person skilled in the art can also appropriately consider these features individually and conclude other combinations of significance.

In which is shown:

figure 1 shows a cross-sectional view of an expansion valve,

figure 2 shows a cross-sectional view of the pressure vessel and adapter of the expansion valve of figure 1 in a non-welded state,

figure 3 shows a detail of figure 2,

FIG. 4 shows a cross-sectional view of a construction known in the prior art, and

figure 5 shows a cross-sectional view of one configuration according to the present invention.

Detailed Description

Fig. 1 illustrates a cross-sectional view of an exemplary expansion valve 10 designed to control fluid flow in a fluid passage 38. The expansion valve 10 comprises a valve piston 40 for opening or closing the fluid passage 38. The fluid passage 38 extends in the valve block 16 of the expansion valve 10. Such an expansion valve is described, for example, in DE 102017110343 a 1. The expansion valve 10 has a linear actuator 14 for driving the valve piston 40. The linear actuator 14 includes a shaft 42 and a motor 44 for rotationally driving the shaft 42. The valve piston 40 is linearly moved toward the fluid passage 38 by the shaft 42 to reduce the cross-sectional area of the fluid passage 38 or completely close the fluid passage 38. The valve piston 40 is linearly moved out of the fluid passage 38 by the shaft 42 to increase the cross-sectional area of the fluid passage 38 or open the closed fluid passage 38. The motor 44 includes a stator 46 and a rotor 48. The electric motor 44 is configured as an inner rotor motor. To drive the shaft 42 in rotation, a voltage is applied to the stator windings 50 of the motor 44, which causes a rotational movement of the rotor 48 arranged in the stator 46. The rotor 48 rotates the shaft 42, which shaft 42 is connected to the rotor 48 in a rotationally fixed manner. The rotary movement of the shaft 42 is converted into a linear movement of the valve piston 40 by means of the thread 52. Furthermore, the expansion valve 10 comprises a circuit board 54 on which an electronic circuit for controlling the electric motor 44 is arranged. The shaft 42 of the linear actuator 14 can be moved inside the pressure vessel 12 of the expansion valve 10 by means of a motor 44. The linear actuator 14 comprises a ball bearing 56 for rotatably supporting a first end 58 of the shaft 42, wherein the first end 58 of the shaft 42 faces the valve piston 40 of the expansion valve 10. In order to support a second end 60 of the shaft 42, which is axially opposite the first end 58 of the shaft 42, the linear actuator 14 has a plain bearing unit 62. The plain bearing unit 62 includes a bearing body 64 having a bearing recess 68 for receiving the second end 60 of the shaft 42. The second end 60 of the shaft 42 is slidably supported within a bearing recess 68 of the bearing body. The sliding bearing unit 62 is inserted into the pressure vessel 12 of the expansion valve 10. The pressure vessel 12 has a dome-shaped section 70. The plain bearing unit 62 is accommodated in a dome-shaped section 70 of the press housing 12.

The expansion valve 10 has an adapter 18 for connecting the pressure vessel 12 with the valve block 16. The adapter 18 has external threads 72 for threading into corresponding internal threads 74 of the valve block 16. The base region (German: Fu. beta. bereich)26 of the pressure vessel 12 is inserted into the adapter 18. The welding lip 22 of the adapter 18 surrounds the wall 24 of the pressure vessel 24 in the circumferential direction in a base region 26 of the pressure vessel 12. The pressure vessel 24 is connected to the adapter 18 by means of a circumferential weld seam 20. The weld seam 20 is produced by means of laser welding. The pressure vessel 12 or the base region 26 of the pressure vessel 12 and the adapter 18 are arranged in the manner of a lap joint, and the weld seam 20 is configured as a fillet weld.

Fig. 2 shows the pressure vessel 12 and the adapter 18 in a non-welded state in a sectional view. For reasons of clarity, other elements of the expansion valve 10 are not shown here. Fig. 3 shows detail X from fig. 2 in an enlarged view. The base region 26 of the pressure vessel 12 is inserted into the adapter 18. The welding lip 22 of the adapter 18 surrounds the wall 24 of the pressure vessel 12 in the circumferential direction in a base region 26 of the pressure vessel 12. In the region of the weld seam 20 to be formed for connecting the pressure vessel 12 to the adapter 18, the wall thickness 32 of the weld lip 22 of the adapter 18 is greater than the wall thickness 30 of the wall 24 of the pressure vessel 12. The wall thickness 32 of the welding lip 22 of the adapter 18 in the region of the weld seam 20 to be formed is preferably between 10% and 40% greater than the wall thickness 30 of the wall 24 of the pressure vessel 12. Preferably, the wall 24 of the pressure vessel 12 has a wall thickness 30 of 0.7mm, while the welding lip 22 of the adapter 18 has a wall thickness 32 of between 0.77mm and 1.0mm in the region of the weld seam 20 to be formed. The different wall thicknesses result in the highest stresses moving to an unfavourable position and/or a notch effect. In order to achieve a uniform stress distribution, the welding lip 22 of the adapter 18 has a circumferential material thinning 34 in a region spaced apart from the weld seam 20 to be formed. The minimum wall thickness 36 of the welding lip 22 of the adapter 18 in the region of the material thinning 34 at least substantially corresponds to the wall thickness 30 of the wall 24 of the pressure vessel 12.

It can be seen from fig. 4 and 5 how the greater wall thickness 32 of the welding lip 22 of the adapter 18 relative to the wall thickness 30 of the wall 24 of the pressure vessel 12 influences the geometry of the weld seam 20 and in particular the seam thickness 28 of the weld seam.

Fig. 4 shows a sectional view of a construction known from the prior art, in which the wall thickness 30 of the wall of the pressure vessel 12 is substantially the same as the wall thickness 32 of the welding lip 22 of the adapter 18. As shown in the micrographs from which a plurality of weld seams are analyzed, the root point 78 of the weld seam 20 is always located on the horizontal line 76 of the chamfer (German: Fase)72 of the welding lip 22 of the adapter 18 with the radially outer edge 74. The seam thickness 28 of the weld seam 20 corresponds to the height of the drawable triangle measured to the root point 78 of the weld seam 20. Since the position of the root point 78 is accordingly determined by the wall thickness 32 of the welding lip 22 of the adapter 18, a joint thickness 28 of the weld seam 20 results in this configuration, which is smaller than the wall thickness 30 of the wall 24 of the pressure vessel 12 and the wall thickness 32 of the welding lip 22 of the adapter 18. Thus, the weld 20 is the weakest link in the welded composite.

Fig. 5 shows a sectional view of a configuration according to the invention in which the wall thickness 32 of the welding lip 22 of the adapter 18 is greater than the wall thickness 30 of the wall of the pressure vessel 12, with the angle of the chamfer 72 remaining constant. The root point 78 of the weld seam 20 is also located here on the horizontal line 76 of the chamfer 72 of the welding lip 22 of the adapter 18 with the radially outer edge 74. The seam thickness 28 of the weld seam 20 corresponds to the height of the drawable triangle measured to the root point 78 of the weld seam 20. Since the deeper position of the root point 78 compared to the configuration of fig. 4 is accordingly determined by the wall thickness 32 of the welding lip 22 of the adapter 18, a joint thickness 28 of the weld seam 20 is produced in this configuration, which corresponds to the wall thickness 30 of the wall 24 of the pressure vessel 12. Thus, the weld 20 has improved stability relative to the configuration of fig. 4. In order to achieve a uniform stress distribution, the welding lip 22 of the adapter 18 has a circumferential material thinning 34 in a region spaced apart from the weld seam 20. The minimum wall thickness 36 of the welding lip 22 of the adapter 18 in the region of the material thinning 34 corresponds to the wall thickness 30 of the wall 24 of the pressure vessel 12.

Reference numerals

10 an expansion valve; 12 a pressure vessel; 14 a linear actuator; 16 a valve block; 18 an adapter; 20 welds (German: Schwei β naht); 22 a weld lip adapter; a 24-wall pressure vessel; 26 a base region; 28 seam thickness (German: NaHtdicke); a 30 wall thickness pressure vessel; a 32 wall thickness weld lip; 34 material thinning part; 36 minimum wall thickness; 38 a fluid channel; a 40-valve piston; 42 shafts; 44 a motor; 46 a stator; 48 rotors; 50 stator windings; 52 a thread; 54 a circuit board; 56 ball bearings; 58 end portion; 60 ends; 62 a plain bearing unit; 64 a bearing body; 68 a bearing recess; a segment 70; 72 chamfering; 74 edges; 76 horizontal lines; 78 root point.

Claims

1. An expansion valve having a pressure vessel (12) for partially accommodating a linear actuator (14), a valve block (16) and an adapter (18) for connecting the pressure vessel (12) to the valve block (16), wherein a base region (26) of the pressure vessel (12) is at least partially inserted into the adapter (18), a welding lip (22) of the adapter (18) surrounds a wall (24) of the pressure vessel (12) in the base region (26) of the pressure vessel (12) in the circumferential direction, and the pressure vessel (12) is connected to the adapter (18) by means of a circumferential weld seam (20), characterized in that the seam thickness (28) of the weld seam (20) at least substantially corresponds to the wall thickness (30) of the wall (24) of the pressure vessel (12).

2. An expansion valve according to claim 1, wherein the wall thickness (32) of the welding lip (22) of the adapter (18) in the region of the weld seam (20) is greater than the wall thickness (30) of the wall (24) of the pressure vessel (12).

3. An expansion valve according to claim 1 or 2, wherein the wall thickness (32) of the welding lip (22) of the adapter (18) in the region of the weld seam (20) is 10% to 40% greater than the wall thickness (30) of the wall (24) of the pressure vessel (12).

4. An expansion valve according to claim 2 or 3, wherein the wall (24) of the pressure vessel (12) has a wall thickness (30) of 0.7mm and the welding lip (22) of the adapter (18) has a wall thickness (32) of 0.77mm to 1.0mm in the region of the weld seam (20).

5. An expansion valve according to any of the preceding claims, wherein the welding lip (22) of the adapter (18) has a circumferential material thinning (34) in a region spaced apart from the weld seam (20).

6. An expansion valve according to claim 5, wherein the minimum wall thickness (36) of the welding lip (22) of the adapter (18) in the region of the material thinning (34) at least substantially corresponds to the wall thickness (28) of the wall (24) of the pressure vessel (12).

7. An adapter for an expansion valve (10) according to any of the preceding claims, wherein the welding lip (22) of the adapter (18) has a circumferential material thinning (34) in a region spaced apart from the weld seam (20).