CN219413920U - Small-sized branch pipe - Google Patents

Abstract

The utility model provides a small-size branch pipe, which comprises a main pipe, a first branch pipe and a second branch pipe, wherein the second branch pipe comprises an extrusion section and an extension section welded and connected with the extrusion section; the extrusion section and the first branch pipe extend to two sides of the main pipe respectively, and the main pipe, the first branch pipe and the extrusion section are integrally formed by extrusion and are mutually communicated through the communication area. The outer wall of the first branch pipe and the outer wall of the extrusion section are in transitional connection through the first circular arc section, the radius R1 of the intersection of the first circular arc section and the axis extension line of the main pipe meets 0.25D which is less than or equal to R1 and less than or equal to 0.8D, D is the outer diameter of the first branch pipe at the tail end of the first circular arc section, and D is more than or equal to 7mm and less than or equal to 19mm. The outer peripheral wall of the communication area which is respectively connected with the main pipe, the first branch pipe and the extrusion section is provided with at least one bulging surface which is used for enlarging the inner cavity of the communication area and is in a plane or is close to the plane, and the vertical distance L of the outer peripheral wall of the cross section of the communication area at the bulging surface is more than or equal to 0.7D and less than or equal to 1.3D.

Description

Small-sized branch pipe

Technical Field

The utility model relates to the field of refrigeration system accessories, in particular to a small-size branch pipe.

Background

A multi-connected air conditioner (heat pump) system is a direct evaporative air conditioning system formed by connecting an outdoor unit with a plurality of indoor units by a specified pipeline on an engineering site. In a multi-connected air conditioning (heat pump) unit, a special branch pipe with a branching or converging function is required to be used for connection in order to realize the distribution of the refrigerant in the pipeline. Although the manifold is similar to a tee but different from a tee fitting; firstly, the three connecting ends of the three-way pipe are all very short, the ratio of the length of each connecting end to the outer diameter of the three-way pipe is below 2 times, so that the three connecting ends are easy to extrude and form, but the three connecting ends are very short, if the three connecting ends are directly welded with a pipe on a multi-connected air conditioner (heat pump) system, the heat transfer is extremely easy to cause secondary melting of a welding line to generate leakage, and meanwhile, when the length of each connecting end is lengthened to the pipe diameter of more than 2 times, the manufacturing difficulty is increased by geometric times (material nonlinearity, geometric nonlinearity and complex boundary conditions are required to be considered, the influence factors are more, and the rule is difficult to form to quantitatively express). In addition, the three connecting ends of the three-way pipe are all fixed in port size, so that the three-way pipe cannot be connected with various-sized pipes on the air conditioning system pipeline. The branch pipe is used as an important connecting part of a multi-connected air conditioner (heat pump) system, and three connecting ends are long in length and each end is provided with a plurality of ports with different specifications and sizes to meet the connection requirements of pipelines with different specifications of different power air conditioners.

The traditional branch pipe is a multi-welding-point combined structure, and mainly comprises two types: one is a three-joint structure 401,402,403 formed by welding a tee and three extension pipes (as shown in fig. 1 and 2). The tee in fig. 1 is a trousers tee structure, and the processing procedures are as follows: firstly, flaring one end of a pipe fitting; and then, flattening the two peripheral walls of the flaring region along the axial direction to form two branch pipes with the cross sections of 8 shapes, wherein the processing flow chart is shown in fig. 1A, and the right side in fig. 1A is a schematic cross section of the corresponding procedure on the left side. The tee in fig. 2 is a U-shaped tee structure, and as shown in fig. 2A, the tee of the structure is generally formed by extrusion. Whether the tee of fig. 1A or the tee of fig. 2A, the three connection ends of both are short, and when used to form the manifold, it is necessary to weld extension tubes to the three connection ends to form the combined manifold structure of fig. 1 and 2. Another combined manifold structure is that a connector 402' is formed on the side wall of the collecting pipe, and two welding points of two extension pipes are welded on the connector 402' and the end 401' of the collecting pipe (as shown in fig. 3). The traditional multi-welding-spot branch pipe has the problems of difficult welding, easy leakage of welding parts, easy falling of extension pipes and the like.

In order to solve the problems of the conventional multi-welding-point branch pipe, the applicant proposes a branch pipe (as shown in fig. 4) with an integrally formed pipe body after extrusion in patent CN208282360U, in which one branch pipe and a main pipe are of an integral structure and the length thereof is enough to meet the pipeline connection requirement of a multi-connected air conditioner (heat pump) system, and the whole product has only one welding point on the second branch pipe, so that the welding line is less, the structure is simple, and the safety performance is high. The pipe body in the branch pipe of the structure adopts an internal high-pressure water extrusion molding technology during processing, and metal materials on the main pipe and the first branch pipe gradually migrate to the extrusion section under the action of internal high pressure. Because the branch pipe is wholly Y-shaped, the included angle between two branch pipes and the included angle between the main pipe and the extrusion section can obstruct the flow of materials, especially for the branch pipe with the pipe diameter smaller than 19mm, the resistance can cause that very high internal pressure is required to push the materials to flow (more than 30Mpa higher than products with other pipe diameters) during extrusion, the extrusion difficulty is high, the extruded products are extremely easy to wrinkle at the communicating area, and the extrusion qualification rate of the small-specification branch pipe with the pipe diameter smaller than 19mm is seriously affected.

Disclosure of Invention

The utility model provides a small-specification branch pipe capable of greatly improving extrusion qualification rate in order to overcome the defects of the prior art.

In order to achieve the above object, the present utility model provides a small-sized branch pipe including a main pipe, a first branch pipe, and a second branch pipe including an extrusion section and an extension section welded to the extrusion section; the extrusion section and the first branch pipe extend to two sides of the main pipe respectively, and the main pipe, the first branch pipe and the extrusion section are integrally formed by extrusion and are mutually communicated through the communication area. The outer wall of the first branch pipe and the outer wall of the extrusion section are in transitional connection through the first circular arc section, the radius R1 of the intersection of the first circular arc section and the axis extension line of the main pipe meets 0.25D which is less than or equal to R1 and less than or equal to 0.8D, D is the outer diameter of the first branch pipe at the tail end of the first circular arc section, and D is more than or equal to 7mm and less than or equal to 19mm. The length of the main pipe is greater than or equal to twice the outer diameter of the first branch pipe at the tail end of the first circular arc section, and the length of at least one of the two branch pipes is greater than four times the outer diameter of the first branch pipe at the tail end of the first circular arc section. The outer peripheral wall of the communication area which is respectively connected with the main pipe, the first branch pipe and the extrusion section is provided with at least one bulging surface which is used for enlarging the inner cavity of the communication area and is in a plane or is close to the plane, and the vertical distance L of the outer peripheral wall of the cross section of the communication area at the bulging surface is more than or equal to 0.7D and less than or equal to 1.3D.

According to an embodiment of the utility model, the surface of the bulging surface is substantially flush with the extension of the busbar of the peripheral wall of the main tube at the overswelling surface.

According to one embodiment of the utility model, the outer peripheral wall of the communication zone is provided with two opposite bulging surfaces, and the vertical distance L of the cross section of the communication zone at the position of the over-bulging surfaces is the vertical distance between the two bulging surfaces.

According to an embodiment of the present utility model, the bulging surface is triangular, and the area of the bulging surface is smaller than or equal to the area of a projection surface of the peripheral wall of the communication area in a direction perpendicular to the bulging surface.

According to an embodiment of the utility model, the first arc segment is a continuous arc segment of equal fillet radius; alternatively, the first circular arc segment includes at least two circular arc sub-segments having different fillet radii.

According to one embodiment of the utility model, the peripheral wall of the main pipe is transited to the communication area through the second arc section at one side close to the first branch pipe, and the fillet radius of the second arc section is R2; the peripheral wall of the main pipe is transited to the communication area through the third arc section at one side close to the extrusion section, and the radius of the fillet of the third arc section is R3, wherein R2 is more than or equal to R3.

According to an embodiment of the utility model, the fillet radius R2 of the second arc segment satisfies: r2 is more than or equal to 0.6D and less than or equal to 2D, D is the outer diameter of the first branch pipe at the tail end of the first arc section, and D is more than or equal to 7mm and less than or equal to 19mm.

According to one embodiment of the utility model, a first included angle alpha 1 is formed between the axis of the main pipe close to the communication area and the axis of the first branch pipe close to the communication area, and the angle alpha 1 is 110 degrees or more and 160 degrees or less; the axis line of the main pipe close to the communication area and the axis line of the extrusion section close to the communication area form a second included angle alpha 2, and the angle alpha 2 is more than or equal to 110 degrees and less than or equal to 160 degrees.

According to an embodiment of the utility model, the number of round bends on the first branch pipe and the second branch pipe is one, and at least one of the axial leads of the tail ends of the two branch pipes is parallel to the axial lead of the main pipe close to the communicating area.

According to one embodiment of the utility model, the tail end of the extension section on the second branch pipe extends to the side of the main pipe, and an included angle between the tail end axial lead of the extension section and the axial lead of the main pipe close to the communication area is 80 degrees or more and less than or equal to 100 degrees.

In summary, according to the small-sized branch pipe provided by the utility model, the fillet radius R1 of the first circular arc section on the axis extension line of the main pipe is controlled to lift the cavity of the communicating region, so that the fluidity of the metal material during extrusion is optimized, and the metal material can smoothly migrate to the extrusion section under a smaller internal high pressure. Meanwhile, the upper limit value of the fillet radius R1 is accurately controlled, so that the extrusion pass rate is improved by ensuring that the extrusion section after extrusion has enough straight sections to match with the welding of the extension section and simultaneously considering the pressure resistance of the communication area during extrusion. Furthermore, the expansion surface which is at least one plane or is close to the plane is arranged on the peripheral wall of the communication area which is respectively connected with the main pipe, the first branch pipe and the extrusion section on the basis of the radius R1 of the round angle, the cavity area of the communication area is further increased along the direction vertical to the expansion surface so as to further optimize the fluidity of the metal material, and the qualification rate of the extruded small-specification branch pipe is effectively improved while the extrusion difficulty is reduced.

The foregoing and other objects, features and advantages of the utility model will be apparent from the following more particular description of preferred embodiments, as illustrated in the accompanying drawings.

Drawings

Fig. 1 is a schematic view showing a conventional branch pipe having three welding points, which is formed of a pants-type tee.

Fig. 1A is a schematic processing diagram of the pant-type tee of fig. 1.

Fig. 2 is a schematic diagram of a prior art manifold with three welds formed from a U-shaped tee.

Fig. 2A is a schematic structural diagram of the U-shaped tee in fig. 2.

Fig. 3 is a schematic diagram of a prior art manifold having two welds.

Fig. 4 is a schematic structural view of a conventional branch pipe integrally formed by extruding a pipe body.

Fig. 5 is a schematic structural diagram of a small-sized branch pipe according to an embodiment of the present utility model.

Fig. 6 is a schematic front view of fig. 5.

Fig. 7 is a side view of fig. 6.

Fig. 8 is a schematic cross-sectional view of fig. 6 taken along line A-A.

Fig. 9 is a schematic view showing the structure of the main pipe, the first branch pipe and the extrusion section of fig. 5 after extrusion.

Fig. 10 is a schematic view of a communication area peripheral wall without bulging surface after extrusion, and in fig. 10, the communication area peripheral wall has a curved surface structure.

Fig. 11, 12 and 13 are schematic structural views of a small-sized branch pipe according to another embodiment of the present utility model.

Fig. 14 is a schematic structural diagram of a small-sized branch pipe according to a second embodiment of the present utility model.

Detailed Description

Example 1

In the existing branch pipe formed by extruding the pipe body integrally, the product with the pipe diameter smaller than 19mm is extremely easy to have the bad phenomenon of wrinkling after extrusion. After anatomical analysis of the defective products, it was found that the wrinkled defective products exhibited a significant increase in wall thickness at the communication area between the first branch pipe and the extrusion section, thereby exhibiting a wrinkled phenomenon on the outer peripheral wall. In this regard, the inventors conducted a great deal of experiments and simulations on the increase in wall thickness of the communication region between the first branch pipe and the extrusion section, and the analysis results all showed that: the increase in wall thickness is due to the accumulation of material caused by the unsmooth flow of the metal material due to the large resistance, and the hardness is increased.

In view of this, the present embodiment provides a small-sized branch pipe for improving fluidity of metal material during extrusion by increasing the cavity area of the communicating region, thereby solving wrinkling of the extruded product. As shown in fig. 5 to 9, the small-sized branch pipe provided in the present embodiment includes a main pipe 1, a first branch pipe 2, and a second branch pipe 3, the second branch pipe 3 including an extrusion section 31 and an extension section 32 welded to the extrusion section 31. The extrusion section 31 and the first branch pipe 2 extend to two sides of the main pipe 1 respectively, and the main pipe 1, the first branch pipe 2 and the extrusion section 31 are integrally formed by extrusion and are mutually communicated through the communication area 10. The main pipe 1 distributes the refrigerant to the first branch pipe 2 and the extrusion section 31; alternatively, the refrigerants in the first branch pipe 2 and the extrusion section 31 are converged to the main pipe 1.

The outer wall of the first branch pipe 2 and the outer wall of the extrusion section 31 are in transitional connection through the first circular arc section 101, the radius R1 of the intersection of the first circular arc section 101 and the axis extension line of the main pipe 1 meets the condition that R1 is more than or equal to 0.25D and less than or equal to 0.8D, D is the outer diameter of the first branch pipe 2 at the tail end of the first circular arc section 101, and D is more than or equal to 7mm and less than or equal to 19mm.

The peripheral wall of the communication area respectively connected with the main pipe 1, the first branch pipe 2 and the extrusion section 31 is provided with at least one bulging surface 100 which is used for enlarging the inner cavity of the communication area 10 and is in a plane or close to the plane, and the vertical distance L of the peripheral wall of the cross section of the communication area at the bulging surface 100 is more than or equal to 0.7D and less than or equal to 1.3D. The small-sized branch pipe according to the embodiment means: a branch pipe with the outer diameter D of 7mm or more and 19mm or less of the first branch pipe 2 at the tail end of the first arc section 101; wherein the outer diameter of the first branch pipe 2 refers to the nominal outer diameter.

In the small-sized branch pipe provided in this embodiment, the length of the main pipe 1 and at least one branch pipe is long (the length is far longer than the length of the connecting end of the conventional three-way pipe fitting), and the pipe in the multi-connected air conditioner (heat pump) unit can be directly connected. Specifically, the length H1 of the main pipe 1 is equal to or greater than twice the outer diameter D of the first branch pipe at the end of the first circular arc segment 101, and the length H2 of the first branch pipe is equal to or greater than four times the outer diameter D of the first branch pipe at the end of the first circular arc segment. However, the present utility model is not limited in any way thereto. In other embodiments, it is also possible to provide the second branch pipe including the extrusion section and the extension section with a length H3 equal to or greater than four times the outer diameter D of the first branch pipe at the end of the first circular arc section; alternatively, the lengths of the first branch pipe and the second branch pipe are each greater than four times the outer diameter D of the first branch pipe at the end of the first circular arc segment.

As shown in fig. 6, the axes of the first branch pipe 2 and the extrusion section 31 near the communication area 10 intersect with the axis of the main pipe 1 near the communication area 10 at a reference point O, the length H1 of the main pipe 1 refers to the vertical distance from the main pipe end face to the section where the reference point O is located, and the lengths H2, H3 of the two branch pipes refer to the vertical distance from the branch pipe end face to the section where the reference point is located.

For the small-sized branch pipe, the communication area 10 formed by the corresponding main pipe 1, the first branch pipe 2 and the extrusion section 31 is smaller because the overall pipe diameter is smaller. During extrusion, the deformation and the direction-changing flow of the metal material under the action of the internal high pressure at the communicating region 10 are greatly hindered, the fluidity of the metal material at the position is poor, the material is easily accumulated, the wall thickness at the position is increased, and even the phenomenon of wrinkling occurs. The manifold provided in this embodiment increases the cavity in the communication area 10 from the axial direction of the main pipe 1 by controlling the fillet radius R1 of the first circular arc segment 101 at the intersection of the axis extension lines of the main pipe 1, thereby improving the fluidity of the metal material. Furthermore, the increase in fillet radius R1 also reduces the curvature of the first circular arc segment 101, and the metallic material can better overcome the curvature obstruction to migrate to the extruded segment 31. Smooth migration of the metal material tends to effectively reduce the wall thickness at the first circular arc section 101, so that the problem that the existing branch pipe is easy to wrinkle due to the fact that the wall thickness is increased at the first circular arc section 101 is effectively solved, and meanwhile the length of the extrusion section 31 is ensured, and meanwhile inner high pressure and extrusion difficulty required by extrusion are effectively reduced.

While the increase in the fillet radius R1 optimizes the fluidity of the metal material during extrusion, it also increases the distance of the outer wall of the pipe from the fillet area on the die (the fillet area on the die refers to the area of the die corresponding to the first arc segment 101) during extrusion. In the extrusion process, the materials on the main pipe 1 and the first branch pipe 2 need to be thinned and transferred to the round corner area on the die so as to expand and deform greatly. On the one hand, the wall thickness of the first circular arc section can be thinned when the distance from the outer wall of the pipe fitting to the circular angle area on the die is too large; on the other hand, the outer wall of the first circular arc section can not be attached to the inner wall of the die cavity, and when the inner high pressure of 100Mpa is born, the problem that the pipe explosion cracks easily occurs at the first circular arc section. Furthermore, based on the main pipe 1 and the first branch pipe 2 of which the wall thicknesses are determined, the increase in the communication area due to the increase in the corner radius R1 tends to shorten the length of the extruded section 31. To ensure that the extruded section 31 has a sufficient length, the wall thickness of the initially extruded tube needs to be increased, which directly results in a significant increase in cost. Therefore, based on the comprehensive consideration of the yield of the extruded product (including poor wrinkling and excessive pipe bursting caused by too small cavity in the communication area) and the product cost, it is necessary to precisely control the corner radius R1 at the intersection of the first circular arc segment 101 and the axis extension line of the main pipe 1. The inventor obtains after a large number of experimental analyses and verification: r1 is more than or equal to 0.25D and less than or equal to 0.8D; preferably, R1 is set to be more than or equal to 0.45D and less than or equal to 0.75D. However, the present utility model is not limited in any way thereto. In other embodiments, the corner radius R1 may take other values within 0.25 D.ltoreq.R1.ltoreq.0.8D.

The fillet radius R1 on the first circular arc segment 101 is limited to the cavity volume lift in the communication zone 10 based on the potential for pipe bursting during extrusion and the impact of pipe costs. In order to improve the fluidity of the metal material during extrusion, the manifold provided in this embodiment further provides at least one bulging surface 100 on the peripheral wall of the communication area, which is respectively connected to the main pipe 1, the first branch pipe 2, and the extrusion section 31, for enlarging the inner cavity of the communication area and is planar or nearly planar. The bulging surface 100 is formed by bulging the peripheral wall of the communication area (curved area formed by intersecting cylinders as shown by reference numeral 100' in fig. 10) of the original curved surface into a plane; in other words, the die cavity volume in the communication area 10 is further increased along the direction perpendicular to the bulging surface so as to optimize the fluidity of the metal material at the communication area 10 during extrusion, thereby further increasing the yield after extrusion. The plane or the close plane and the limitation of the vertical distance L of the outer peripheral wall of the cross section of the communication area at the over-bulging surface also enable the metal material to smoothly and uniformly migrate to the bulging surface, so that the bulging surface 100 after extrusion can be well attached to the inner wall of the cavity of the extrusion die to bear the internal high pressure.

In this embodiment, the outer peripheral wall of the communication area 10 has two opposite bulging surfaces 100, and the surface of the bulging surface 100 is substantially flush with the extension line of the bus bar of the outer peripheral wall of the main pipe at the overstretching surface 100. The vertical distance L of the cross section of the communication zone at the over-bulging surface is the vertical distance between the two bulging surfaces and L is close to the outer diameter of the main pipe near the communication zone 10 and the outer diameter D of the first branch pipe at the end of the first circular arc segment 101, i.e. l≡d. However, the present utility model is not limited in any way thereto. In other embodiments, the peripheral wall of the communication area may have only one bulging surface, and the vertical distance L of the peripheral wall of the cross section of the communication area at the bulging surface may be 0.7 d+.l+.1.3D. Preferably, other values within 0.9 D.ltoreq.L.ltoreq.1.2D may be set, if L=1.05D or L=0.95D etc.

As shown in fig. 5 and 6, the bulging surface 100 is triangular and the area of the bulging surface 100 is equal to or smaller than the area of the projection surface of the outer peripheral wall of the communication area 10 in the direction perpendicular to the bulging surface. However, the present utility model is not limited in any way to the specific shape of the bulging surface. In other embodiments, the shape of the extrusion die at the region corresponding to the bulging surface may be adjusted based on the processing requirements.

In the present embodiment, the first arc segment 101 is a continuous arc segment with equal corner radius R1. However, the present utility model is not limited in any way thereto. For small-sized branch pipes with slightly larger pipe diameters, for example, the outer diameter D of the first branch pipe 2 at the end of the first circular arc section 101 is 15.88mm (as shown in fig. 11) and 19mm (as shown in fig. 12), the increase of the outer diameter D also further increases the cavity volume in the communication area 10. Thus, it may be provided that the first circular arc segment 101 comprises at least two circular arc sub-segments having different fillet radii; specifically, the first arc section 101 includes a first arc sub-section 1011 near the first branch pipe 1 and a second arc sub-section 1012 near the extrusion section 31, and the axis extension line of the main pipe 1 intersects with the second arc sub-section 1012, and the fillet radius R1 at the intersection still satisfies 0.25D being less than or equal to R1 being less than or equal to 0.8D. The fillet radius at the first arc sub-segment 1011 is greater than the fillet radius R1 of the second arc sub-segment 1012, but the relationship between it and the outer diameter D of the first branch pipe at the end of the first arc segment 101 is not limited in any way. In other embodiments, the axis extension line of the main pipe 1 may be intersected with the first arc subsection 1011, and the fillet radius R1 at the intersection still satisfies 0.25 d.ltoreq.r1.ltoreq.0.8d; the fillet radius at the second circular arc subsection 1012 is greater than the fillet radius R1 of the first circular arc subsection 1011, but the relationship between the fillet radius at the second circular arc subsection 1012 and the outer diameter D is not limited in any way.

In this embodiment, as shown in fig. 5, the outer peripheral wall of the main pipe 1 transitions to the communication area 10 via the second arc segment 102 at the side close to the first branch pipe 2, and the fillet radius of the second arc segment 102 is R2; the peripheral wall of the main pipe 1 is transited to the communication zone 10 through the third arc section 103 at one side close to the extrusion section 31, and the radius of the fillet of the third arc section 103 is R3, wherein R2 is more than or equal to R3. Specifically, the fillet radius R2 of the second arc segment 102 is set to satisfy: r2 is more than or equal to 0.6D and less than or equal to 2D, D is the outer diameter of the first branch pipe 2 at the tail end of the first circular arc section 101, and D is more than or equal to 7mm and less than or equal to 19mm. The setting of the fillet radius R2 of the second arc segment 102 not only can further increase the cavity in the communication area 10 to improve the fluidity of the metal material, but also effectively avoid the accumulation of the material on the second arc segment 102 due to the reduction of the curvature of the second arc segment 102.

Based on the branching pipe structure manufactured from red copper as a raw material shown in fig. 5, the inventors conducted experiments to verify the relationship between the fillet radius R1 of the first circular arc segment 101 and the outer diameter D of the first branch pipe 2 at the end of the first circular arc segment 101.

Test protocol: copper tubes with the same tube diameter are used as extrusion raw materials for testing, the same person operates under the same extrusion equipment parameters in a normal environment, and the qualification rate of the internal high pressure is verified based on different fillet radii Rm at fillet areas on the die. Wherein the fillet radius Rm at the fillet area on the die corresponds to the fillet radius R1 of the first arc segment 101 on the small-sized manifold.

Process test protocol (parameter conditions): (1) test equipment: 150 an extruder; (2) the test method comprises the following steps: selecting the same water extrusion equipment, placing the copper tube into a die cavity after equipment parameter setting is stable, and starting the extrusion equipment to extrude; and counting extrusion qualification rate data of the extrusion pipe after extrusion is completed.

Selecting a test article: copper tubes of four different pipe diameters are selected as extrusion raw materials based on the outer diameter D of a first branch pipe at the tail end of a first arc section to form four experimental groups, a plurality of sub-experimental groups are formed in each experimental group based on different fillet radii Rm at the fillet area on the die, and 20 samples are contained in each sub-experimental group.

The specification selected in the first experiment group isAs an extrusion raw material (i.e., copper tube having an outer diameter of 9.52mm and a wall thickness of 0.7 mm), rm was increased from 1.5mm to 10mm in steps of 0.5mm, and 18 sub-experimental groups were formed in total.

The specification selected in the second experiment group isRm was increased from 2.5mm to 11mm in 0.5mm steps to form 18 sub-groups.

The specification selected in the third experiment group isRm was increased from 3.0mm to 13.5mm in 0.5mm steps to form 22 sub-groups of experiments.

The specification selected in the second experiment group isRm was increased from 4.0mm to 16.5mm in 0.5mm steps to form 26 sub-groups.

The test results show that:

the extrusion qualification rate of the product is controllable when the fillet radius Rm (namely the fillet radius R1 of the first circular arc section 101) at the fillet area on the die in the first experimental group is controlled to be more than 2.0mm and less than 8.5mm, namely R1 is more than or equal to 0.21D and less than or equal to 0.89D.

And when the fillet radius Rm (namely the fillet radius R1 of the first circular arc section 101) at the fillet area on the die in the second experimental group is controlled to be more than 3.0mm and less than 10.5mm, the extrusion qualification rate of the product is controllable, namely R1 is more than or equal to 0.236D and less than or equal to 0.827D.

And in the third experiment group, when the fillet radius Rm (namely the fillet radius R1 of the first circular arc section 101) at the fillet area on the die is controlled to be more than 3.5mm and less than 13mm, the extrusion qualification rate of the product is controllable, namely R1 is more than or equal to 0.22D and less than or equal to 0.819D.

And in the fourth experiment group, when the fillet radius Rm (namely the fillet radius R1 of the first circular arc section 101) at the fillet area on the die is controlled to be more than 4.5mm and less than 15.5mm, the extrusion qualification rate of the product is controllable, namely R1 is more than or equal to 0.237D and less than or equal to 0.816D.

The verification result of the test also shows that, based on the combined action of the fillet radius R1 of the first circular arc segment at the communication zone 10 and the bulging surface 100, when R1 satisfies 0.25 d.ltoreq.r1.ltoreq.0.8d, the main pipe 1, the first branch pipe 2 and the extrusion section 31 have excellent product yield after extrusion.

In this embodiment, as shown in fig. 6, a first included angle α1 is formed between the axis line of the main pipe 1 near the communication area 10 and the axis line of the first branch pipe 2 near the communication area 10, and the angle α1 is 110 degrees or more and 160 degrees or less; the axis line of the main pipe 1 near the communication area 10 and the axis line of the extrusion section 31 near the communication area 10 form a second included angle alpha 2, and the angle alpha 2 is more than or equal to 110 degrees and less than or equal to 160 degrees. The arrangement of the first included angle alpha 1 and the second included angle alpha 2 can promote the refrigerant in the main pipe 1 to be uniformly distributed into the first branch pipe 1 and the second branch pipe 2, so that the overall performance of the multi-connected air conditioner (heat pump) unit is improved.

Further, in this embodiment, the direction in which the refrigerant is output from the two branch pipes is substantially parallel to the direction in which the refrigerant enters the main pipe 1, and the number of round bends on the two branch pipes is the same and is one. The arrangement enables the local resistances of the two branch pipes to be as close as possible, thereby further improving the uniformity of the split flow of the two branch pipes. However, the present utility model is not limited in any way thereto.

As shown in fig. 6, the end of the extrusion section 31 is flared and then welded to the extension section 32. However, the present utility model is not limited in any way thereto. In other embodiments, the extrusion section may also be welded to the extension section. In order to facilitate connection with external pipelines, in the small-sized branch pipe provided in the present embodiment, the main pipe 1 is provided with a main pipe flaring section 11, the first branch pipe 2 is provided with a first branch pipe flaring section 21 and a first branch pipe necking section 22, and the second branch pipe extension section 32 is also provided with a second branch pipe flaring section 321 and a second branch pipe necking section 322. However, the present utility model is not limited in any way thereto. In other embodiments, multiple main pipe flaring segments 11 (fig. 12 and 13), multiple main pipe necking segments, or a combination of main pipe flaring segments 11 and main pipe necking segments 12 (fig. 11) may be provided on the main pipe. Likewise, the first branch and extension sections may be provided with a plurality of flared sections, a plurality of necked sections, or a combination of flared and necked sections (as in fig. 13).

Example two

This embodiment is substantially the same as the first embodiment and its variations, except that: the extending directions of the extending sections on the second branch pipes are different.

Specifically, in the present embodiment, as shown in fig. 14, it is also possible to provide that the refrigerant outflow direction of the first branch pipe 2 is substantially parallel to the main pipe 1, and the end of the extension section 32' of the second branch pipe 3' extends to the side of the main pipe, and the angle between the end axis of the extension section 32' and the axis of the main pipe 1 near the communicating region is 80 degrees- θ -100 degrees.

In summary, according to the small-sized branch pipe provided by the utility model, the fillet radius R1 of the first circular arc section on the axis extension line of the main pipe is controlled to lift the cavity of the communicating region, so that the fluidity of the metal material during extrusion is optimized, and the metal material can smoothly migrate to the extrusion section under a smaller internal high pressure. Meanwhile, the upper limit value of the fillet radius R1 is accurately controlled, so that the extrusion pass rate is improved by ensuring that the extrusion section after extrusion has enough straight sections to match with the welding of the extension section and simultaneously considering the pressure resistance of the communication area during extrusion. Furthermore, the expansion surface which is at least one plane or is close to the plane is arranged on the peripheral wall of the communication area which is respectively connected with the main pipe, the first branch pipe and the extrusion section on the basis of the radius R1 of the round angle, the cavity area of the communication area is further increased along the direction vertical to the expansion surface so as to further optimize the fluidity of the metal material, and the qualification rate of the extruded small-specification branch pipe is effectively improved while the extrusion difficulty is reduced.

Although the utility model has been described with reference to the preferred embodiments, it should be understood that the utility model is not limited thereto, but rather may be modified and varied by those skilled in the art without departing from the spirit and scope of the utility model.

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Claims (10)

1. A small-sized manifold, comprising: the main pipe, the first branch pipe and the second branch pipe, wherein the second branch pipe comprises an extrusion section and an extension section welded and connected with the extrusion section; the extrusion section and the first branch pipe extend to two sides of the main pipe respectively, and the main pipe, the first branch pipe and the extrusion section are integrally formed by extrusion and are communicated with each other through the communication area;

the outer wall of the first branch pipe is in transitional connection with the outer wall of the extrusion section through the first circular arc section, the radius R1 of a fillet at the intersection of the first circular arc section and the extension line of the axis of the main pipe is more than or equal to 0.25D and less than or equal to 0.8D, D is the outer diameter of the first branch pipe at the tail end of the first circular arc section, and D is more than or equal to 7mm and less than or equal to 19mm; the length of the main pipe is more than or equal to twice the outer diameter of the first branch pipe at the tail end of the first circular arc section, and the length of at least one of the two branch pipes is more than four times the outer diameter of the first branch pipe at the tail end of the first circular arc section;

the outer peripheral wall of the communication area which is respectively connected with the main pipe, the first branch pipe and the extrusion section is provided with at least one bulging surface which is used for enlarging the inner cavity of the communication area and is in a plane or is close to the plane, and the vertical distance L of the outer peripheral wall of the cross section of the communication area at the bulging surface is more than or equal to 0.7D and less than or equal to 1.3D.

2. The small gauge branch pipe of claim 1, wherein the surface of the bulging surface is substantially flush with the main pipe peripheral wall busbar extension at the overswelling surface.

3. The small-sized form factor manifold as recited in claim 1, wherein the outer peripheral wall of the communication zone has two oppositely disposed bulging surfaces, and the vertical distance L of the cross section of the communication zone at the over-bulging surface is the vertical distance between the two bulging surfaces.

4. The small-sized form factor branching pipe as set forth in claim 1, wherein the bulging surface is triangular and the area of the bulging surface is equal to or smaller than the area of a projection surface of the outer peripheral wall of the communication area in a direction perpendicular to the bulging surface.

5. The small gauge branch pipe of claim 1, wherein the first arc segment is a continuous arc segment of equal fillet radius; alternatively, the first circular arc segment includes at least two circular arc sub-segments having different fillet radii.

6. The small-sized form factor branching pipe as set forth in claim 1, wherein the outer peripheral wall of the main pipe is transited to the communication area via the second circular arc section on the side close to the first branch pipe and the fillet radius of the second circular arc section is R2; the peripheral wall of the main pipe is transited to the communication area through the third arc section at one side close to the extrusion section, and the radius of the fillet of the third arc section is R3, wherein R2 is more than or equal to R3.

7. The small gauge branch pipe of claim 6, wherein the fillet radius R2 of the second circular arc segment satisfies: r2 is more than or equal to 0.6D and less than or equal to 2D, D is the outer diameter of the first branch pipe at the tail end of the first arc section, and D is more than or equal to 7mm and less than or equal to 19mm.

8. The small-sized branch pipe according to claim 1, wherein a first included angle alpha 1 is formed between the axis line of the main pipe close to the communication area and the axis line of the first branch pipe close to the communication area, and the angle alpha 1 is 110 degrees or less and 160 degrees or less; the axis line of the main pipe close to the communication area and the axis line of the extrusion section close to the communication area form a second included angle alpha 2, and the angle alpha 2 is more than or equal to 110 degrees and less than or equal to 160 degrees.

9. The small-sized form factor branching pipe as set forth in claim 1, wherein the number of round bends in each of the first branch pipe and the second branch pipe is one and at least one of the axes of the ends of the two branch pipes is parallel to the axis of the main pipe near the communication area.

10. The small-sized form factor branching pipe as set forth in claim 1, wherein the end of the extension on the second branch pipe extends to the side of the main pipe, and the angle θ between the axis of the end of the extension and the axis of the main pipe near the communication area is 80 ° or more and 100 ° or less.