A flaring device and method for copper tubes and fins applicable to variable-diameter pipes

Abstract

The present invention relates to the technical field of hydraulic tube expanding. The present invention discloses a tube expanding device for copper tubes and fins applicable to variable-diameter tubes, which comprises a base, on which a supporting mechanism, a tube expanding mechanism and a limiting mechanism are installed. The supporting mechanism is used to support the copper tube and limit and position the copper tube. The tube expanding mechanism is used to perform tube expanding treatment on the copper tube. The inner diameter of the limiting mechanism matches the outer diameter of the copper tube after tube expanding and is used to limit excessive tube expanding of the copper tube. The tube expanding mechanism and the limiting mechanism cooperate to reduce the tensile thinning amount of the copper tube at point a, where point a refers to the connection between the deformed tube expanding section and the undeformed non-tube expanding section of the copper tube. The present invention also discloses a tube expanding method for the tube expanding device of copper tubes and fins applicable to variable-diameter tubes, which divides the tube expanding of the copper tube into two tube expanding deformation operations, can effectively reduce the thinning amount at the connection between the tube expanding section and the non-tube expanding section of the copper tube, and improve the strength of the connection.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic tube expanding, and particularly relates to a tube expanding device for copper tubes and fins applicable to variable-diameter tubes. Background Art

[0002] In the heat exchangers of the prior art, the connection between the copper tube and the fin generally adopts a tube expanding process. It is by the metal deformation and expansion of the copper tube that a pressing force is generated between the outer surface of the copper tube and the inner surface of the mounting hole on the fin, so that the copper tube and the fin are in close and complete contact, which is beneficial to the heat conduction between the copper tube and the fin. Limited by the error of the wall thickness of domestic copper tubes, the liquid bag type tube expanding technology is generally adopted in China. In the existing liquid bag type tube expanding technology, the high-pressure hydraulic pressure provided by a tube expanding machine is applied to the radial pressure generated by a high-pressure resistant elastic rubber body to expand the tube onto the tube sheet. When the ultra-high hydraulic pressure enters the high-pressure resistant elastic rubber body through a high-strength alloy core rod, the high-pressure resistant elastic rubber body generates a radial pressure, and this pressure is sufficient to cause plastic deformation of the tube material, thereby realizing the tube expansion between the tube and the tube sheet. Among them, the high-pressure resistant elastic rubber body is the liquid bag.

[0003] As Figure 11 shown, in the existing liquid bag type tube expanding technology, the tube expansion of the copper tube is formed in one step, and the part of the copper tube that needs to be tube expanded deforms and spreads radially synchronously. Most of the deformation amount generated by the tube expansion of the copper tube is concentrated at both ends of the tube expansion section, that is, at point a formed between the tube expansion section and the non-tube-expanded section of the copper tube, resulting in the part at point a being stretched too thin and the strength being reduced, which affects the overall service performance of the copper tube. Summary of the Invention

[0004] To solve the problems mentioned in the above background, the present invention provides a tube expanding device for copper tubes and fins applicable to variable-diameter tubes.

[0005] To achieve the above technical objectives, the technical solutions adopted by the present invention are as follows.

[0006] A tube expanding device for copper tubes and fins applicable to variable-diameter tubes, which includes a base, on which a support mechanism, a tube expanding mechanism and a limiting mechanism are installed. The support mechanism is used to support the copper tube and limit and position the copper tube. The tube expanding mechanism is used to perform tube expansion treatment on the copper tube. The inner diameter of the limiting mechanism matches the outer diameter of the copper tube after tube expansion and is used to limit the copper tube from excessive tube expansion. The tube expanding mechanism and the limiting mechanism cooperate to reduce the stretching and thinning amount of the copper tube at point a, where point a refers to the connection between the tube expansion section where the copper tube deforms and the non-tube-expanded section where the copper tube does not deform.

[0007] Further, the support mechanism includes a first support frame, a second support frame, and a third support frame installed on the base. A U-shaped support platform for supporting the U-shaped section of the copper tube is provided at the upper end of the first support frame, and straight tube support platforms for supporting the free ends of the straight tube sections of the copper tube are provided at the upper ends of the second support frame and the third support frame.

[0008] Further, the tube expanding mechanism includes a mounting frame installed on the base. A linear module one for driving the mounting frame to displace axially along the straight tube section of the copper tube is provided on the base, and a tube expanding member is provided at the upper end of the mounting frame.

[0009] Further, the tube expanding member includes a connecting rod and a liquid bag type tube expanding unit. The connecting rod is installed on the mounting frame and is coaxially arranged with the straight tube section of the copper tube when the copper tube is supported by the support mechanism. There are several groups of liquid bag type tube expanding units, and adjacent two groups of liquid bag type tube expanding units are coaxially detachably connected. After multiple groups of liquid bag type tube expanding units are connected, a tube expanding element is formed. One end of the tube expanding element is coaxially detachably connected to the connecting rod, and a positioning sleeve is coaxially installed outside the connecting rod.

[0010] Further, the liquid bag type tube expanding units in the tube expanding element are interconnected, the connecting rod and the tube expanding element are interconnected, and the end of the connecting rod is connected to a hydraulic system. The hydraulic system is used to provide hydraulic medium to the tube expanding element.

[0011] Further, in the tube expanding element, the distance between the liquid bags in adjacent two groups of liquid bag type tube expanding units is equal to the axial length of the liquid bag itself.

[0012] Further, the limiting mechanism includes a guide post vertically provided on the base and two groups of limiting units connected to the guide post. The two groups of limiting units are respectively an upper limiting unit and a lower limiting unit.

[0013] Further, the limiting unit includes a main board. The main board in the upper limiting unit is slidably connected to the guide post, and the upper limiting unit can move in the vertical direction. The main board in the lower limiting unit is fixedly connected to the guide post;

[0014] Limiting plates are provided on the facing surfaces of the main boards in the two groups of limiting units. A limiting groove penetrating through its thickness is provided on the surface of the limiting plate facing away from the main board. There are two groups of limiting grooves corresponding to the straight tube section of the copper tube. Multiple groups of limiting plates in each group of limiting units are arranged in an array along the axial direction of the tube expanding element, and the gap between adjacent two groups of limiting plates is used to avoid the fins. The diameter of the limiting groove matches the diameter of the copper tube after tube expansion, and the limiting groove in the lower limiting unit is coaxially arranged with the tube expanding element.

[0015] A tube expanding method for a tube expanding device for expanding a copper tube and fins applicable to a stepped tube:

[0016] Step 1: Support the copper tube through the support mechanism and perform limiting and positioning on the copper tube;

[0017] Step 2: The upper limiting unit moves downward and cooperates with the lower limiting unit to form a complete circular groove through their respective limiting grooves. The circular groove coaxially surrounds the outer part of the straight pipe section of the copper pipe and has a diameter matching the diameter of the copper pipe after tube expansion, restricting excessive deformation of the copper pipe.

[0018] Step 3: The linear module 1 operates to traction the tube expansion member towards the copper pipe, so that the tube expansion member extends into the straight pipe section of the copper pipe. The moving displacement of the tube expansion member is equal to L1 + L2. L1 refers to the distance between the liquid bag in the liquid bag type tube expansion unit farthest from the connecting rod and the fin sleeved on the outer part of the copper pipe and closest to the pipe orifice of the straight pipe section of the copper pipe in the initial state. L2 refers to the axial length of the tube expansion section that needs to be expanded in the copper pipe.

[0019] Step 4: The hydraulic system supplies hydraulic medium, and the hydraulic medium flows into the liquid bags in each group of liquid bag type tube expansion units, causing the copper pipe to undergo the first deformation through the liquid bags.

[0020] Step 5: The hydraulic medium flows back, and the linear module 1 operates to traction the tube expansion member to retreat by L3. L3 refers to the distance between the liquid bags in two adjacent groups of liquid bag type tube expansion units.

[0021] Step 6: The hydraulic system supplies hydraulic medium, and the hydraulic medium flows into the liquid bags in each group of liquid bag type tube expansion units, causing the copper pipe to undergo the second deformation through the liquid bags.

[0022] Step 7: The hydraulic medium flows back, and the linear module 1 tractions the tube expansion member to reset, and the tube expansion is completed.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The tube expansion of the copper pipe in the present invention is realized by two tube expansion deformation operations. Specifically:

[0025] 1. As Figure 11 shown, in the prior art, the tube expansion of the copper pipe is formed in one step. Most of the deformation amount generated by the tube expansion of the copper pipe is concentrated at both ends of the tube expansion section, that is, at point a formed between the tube expansion section and the non-tube expansion section of the copper pipe, resulting in the overly thin stretching at point a, reducing the strength and affecting the overall service performance of the copper pipe. For the convenience of description, an extreme state is taken as an example: the deformation amount generated by the tube expansion of the copper pipe is evenly concentrated at two point a, and the total deformation amount is N1, and the deformation amount at each point a is N1 / 2.

[0026] As Figure 12 shown, in this solution, during the first deformation process of the copper pipe, point b in the tube expansion section deforms, and point c does not deform. The deformation amount of point b is evenly concentrated at two related points d. The total deformation amount of point b is N2, and the deformation amount at each point d is N2 / 2.

[0027] Also, since the axial length of b is less than the axial length of the copper tube formed by one-time tube expansion in the prior art, N2 is less than N1. Specifically, taking the example of five groups of liquid bag type tube expansion units, since the distance between the liquid bags in two adjacent groups of liquid bag type tube expansion units is equal to the axial length of the liquid bag itself, the axial length of the liquid bag in each group of liquid bag type tube expansion units is equal to one-ninth of the axial length of the copper tube formed by one-time tube expansion in the prior art. Correspondingly, N2 is equal to one-ninth of N1, so the deformation amount at point d is equal to one-ninth of the deformation amount at point a;

[0028] During the second deformation process of the copper tube, c deforms. After the second deformation, the entire tube expansion of the copper tube is completed. At this time, the connection point formed between the expanded tube section and the unexpanded tube section of the copper tube is point e, and the deformation amount at point e is equal to the deformation amount at point d. That is to say, compared with the prior art, the deformation amount at the connection point between the expanded tube section and the unexpanded tube section of the copper tube in this solution is reduced by eight-ninths;

[0029] Generally speaking, compared with the prior art, this solution can reduce the thinning amount at the connection point between the expanded tube section and the unexpanded tube section during the tube expansion process of the copper tube, improve its strength, and is beneficial to the overall use of the copper tube.

[0030] Second, in addition, during the first and second deformation processes of the above copper tube, there are limiting mechanisms to prevent the copper tube from undergoing excessive deformation;

[0031] In addition, during the second deformation process of the above copper tube, when c deforms, it will cause d at both ends of c to also deform. At this time, d is not thinned, but thickened, and a scar f is formed between b and c. However, as is well known, the purpose of expanding the connection between the copper tube and the fin in the heat exchanger is to make the copper tube and the fin in close and complete contact, which is beneficial to the heat conduction between the copper tube and the fin. In this solution, the copper tube has achieved tube expansion, achieved close and complete contact between the copper tube and the fin, and completely achieved the purpose of expanding the connection between the copper tube and the fin in the heat exchanger. The scar f does not affect the achievement of this purpose. In addition, the existence of the scar f also increases the contact area between the copper tube at point f and the heat conduction medium (usually water) inside the copper tube.

[0032] Combining one and two, on the premise of completely achieving the purpose of expanding the connection between the copper tube and the fin in the heat exchanger, this solution can reduce the thinning amount at the connection point between the expanded tube section and the unexpanded tube section during the tube expansion process of the copper tube, improve its strength, is beneficial to the overall use of the copper tube, and the formed scar f can also increase the contact area between the copper tube at point f and the heat conduction medium inside the copper tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic structural diagram of the present invention;

[0034] Figure 2 It is a structural schematic diagram of the tube expanding mechanism;

[0035] Figure 3 It is a schematic diagram of the positioning sleeve, connecting rod and liquid bag type tube expanding unit;

[0036] Figure 4 It is a schematic diagram of the liquid bag type tube expanding unit and the cap;

[0037] Figure 5 It is an exploded view of the second motor, movable sleeve, fixed sleeve and connecting rod;

[0038] Figure 6 It is an exploded view of the fixed sleeve and the shaping rod;

[0039] Figure 7 It is a schematic diagram of the support mechanism and the limiting mechanism;

[0040] Figure 8 It is a schematic diagram of the support mechanism and the lower limiting unit;

[0041] Figure 9 It is a schematic diagram of the limiting unit;

[0042] Figure 10 It is an exploded view of the limiting plate and the laminated sheet;

[0043] Figure 11 In the prior art, it is a schematic diagram after the copper tube is expanded;

[0044] Figure 12 In this solution, it is a schematic diagram of the process of expanding the copper tube.

[0045] The reference numerals in the drawings are:

[0046] 100, support mechanism; 101, U-shaped support table; 102, straight tube support table;

[0047] 200, tube expanding mechanism; 201, mounting frame; 202, first lead screw; 203, first motor; 204, tube expanding member; 205, second motor; 206, power transmission member; 207, positioning sleeve; 2071, movable sleeve; 2072, linkage hole; 2073, fixed sleeve; 2074, guide groove; 2075, centering rod; 2076, linkage pin; 208, connecting rod; 2081, first threaded convex rod; 209, liquid bag type tube expanding unit; 2091, second threaded convex rod; 2092, threaded groove; 210, cap;

[0048] 300, limiting mechanism; 301, guide post; 302, third motor; 303, second lead screw; 304, limiting unit; 305, main board; 306, limiting plate; 307, limiting groove; 308, laminated sheet. Detailed implementation method

[0049] To further illustrate the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation manners, structures, features and effects according to the present invention as follows.

[0050] As Figures 1 - 12 shown, a flaring device for a copper tube and fins applicable to a variable-diameter tube includes a base, on which a support mechanism 100, a tube flaring mechanism 200 and a limiting mechanism 300 are installed. Among them, the support mechanism 100 is used to support the copper tube and position the copper tube, the tube flaring mechanism 200 is used to flare the copper tube, and the inner diameter of the limiting mechanism 300 matches the outer diameter of the flared copper tube, and is used to limit the excessive flaring of the copper tube. In addition, the tube flaring mechanism 200 and the limiting mechanism 300 cooperate to reduce the tensile thinning amount of the copper tube at point a, as Figure 11 shown, point a refers to the connection between the deformed section and the undeformed section of the copper tube. In the existing liquid bag flaring method, the part of the copper tube that needs to be flared and deformed spreads and deforms synchronously along the radial direction, which will cause the connection between the deformed section and the undeformed section of the copper tube, that is, point a, to be stretched too thin, affecting the strength at point a. If the strength at point a is insufficient, it is easy to crack, affecting the overall use of the copper tube. In this solution, the tube flaring mechanism 200 and the limiting mechanism 300 cooperate to reduce the tensile thinning amount of the copper tube at point a. Compared with the prior art, the strength of the copper tube at point a is stronger.

[0051] As Figure 8 shown, the support mechanism 100 includes three groups of support frames installed on the base: support frame one, support frame two and support three. The upper end of support frame one is provided with a U-shaped support table 101 for supporting the U-shaped section of the copper tube, and the upper ends of support frame two and support three are both provided with straight tube support tables 102 for supporting the free ends of the straight tube sections of the copper tube.

[0052] The copper tube in the heat exchanger generally has a U-shaped shape. Through the cooperation of the U-shaped support table 101 and the two straight tube support tables 102, the support of the copper tube can be realized. And because the U-shaped support table 101 corresponds to the copper tube, when the copper tube is supported by the support mechanism 100, limited by the cooperation between the U-shaped support table 101 and the U-shaped section of the copper tube, the position of the copper tube is restricted and fixed, that is, the positioning of the copper tube is completed.

[0053] As Figures 2 - 6As shown, the tube expanding mechanism 200 includes a mounting bracket 201 installed on the base. A linear module one is arranged on the base for driving the mounting bracket 201 to displace axially along the straight tube section of the copper tube. Specifically, the linear module one includes a slide rail and a lead screw one 202 installed on the base. Both the slide rail and the lead screw one 202 are parallel to the axial direction of the straight tube section of the copper tube. The slide rail is slidably connected to the mounting bracket 201, and the lead screw one 202 is threadedly connected to the mounting bracket 201. The input end of the lead screw one 202 is power-connected to a motor one 203 installed on the base. By driving the lead screw one 202 to rotate through the motor one 203, the mounting bracket 201 is driven to displace along the guiding direction of the slide rail.

[0054] A tube expanding member 204 is arranged at the upper end of the mounting bracket 201.

[0055] Specifically, as Figure 3 shown, the tube expanding member 204 includes a connecting rod 208 and a liquid bag type tube expanding unit 209. The connecting rod 208 is installed on the mounting bracket 201 and is coaxially arranged with the straight tube section of the copper tube when the copper tube is supported by the supporting mechanism 100. Since there are two straight tube sections of the copper tube, two sets of tube expanding members 204 are correspondingly arranged. Only one set is shown in the attached drawings of this scheme.

[0056] Several groups of liquid bag type tube expanding units 209 are arranged, and adjacent two groups of liquid bag type tube expanding units 209 are coaxially detachably connected. Specifically, one end of the core rod in the liquid bag type tube expanding unit 209 is provided with a thread groove 2092, and the other end is provided with a threaded convex rod two 2091. Adjacent two groups of liquid bag type tube expanding units 209 are coaxially detachably connected through the thread groove 2092 and the threaded convex rod two 2091. In addition, the liquid bag type tube expanding unit 209 can be realized by existing liquid bag tube expanding technical means and will not be elaborated.

[0057] After several groups of liquid bag type tube expanding units 209 are connected, a complete tube expanding element for performing tube expanding operation on the copper tube is formed. The thread groove 2092 arranged at one end of the tube expanding element cooperates with the threaded convex rod one 2081 arranged at the end of the connecting rod 208 to realize the coaxial detachable connection between the tube expanding element and the connecting rod 208. A cap 210 is installed outside the threaded convex rod two 2091 arranged at the other end of the tube expanding element.

[0058] Preferably, in the tube expanding element, the distance between the liquid bags in adjacent two groups of liquid bag type tube expanding units 209 is equal to the axial length of the liquid bag itself.

[0059] In addition, the sealing performance of the above-mentioned threaded joints can be enhanced by existing technical means. For example, the sealing performance of the above-mentioned joints can be enhanced by using raw material tape, etc.

[0060] A positioning sleeve 207 is coaxially installed outside the connecting rod 208.

[0061] The above-mentioned threaded groove 2092 communicates with the core rod in the liquid bag type tube expanding unit 209. A first connecting hole communicating with the core rod in the liquid bag type tube expanding unit 209 is provided on the second threaded convex rod 2091. A second connecting hole penetrating the axial length of the connecting rod 208 and the first threaded convex rod 2081 is provided on the connecting rod 208.

[0062] The tube expanding process of the tube expanding mechanism 200 is specifically as follows:

[0063] First, place the copper tube on the supporting mechanism 100. Through the cooperation of the U-shaped supporting table 101 and the U-shaped section of the copper tube, the positioning of the copper tube is realized. At this time, the straight tube section of the copper tube and the tube expanding member 204 are coaxially arranged.

[0064] Then, the linear module one operates to traction the tube expanding member 204 to move towards the copper tube, so that the tube expanding member 204 extends into the straight tube section of the copper tube. The moving displacement of the tube expanding member 204 is equal to L1 + L2. L1 refers to the distance between the liquid bag in the liquid bag type tube expanding unit 209 that is farthest from the connecting rod 208 in the initial state and the fin that is sleeved outside the copper tube and closest to the tube orifice of the straight tube section of the copper tube. L2 refers to the distance between the fin that is sleeved outside the copper tube and closest and farthest from the tube orifice of the straight tube section of the copper tube, that is, the axial length of the tube expanding section that needs to be expanded in the copper tube. Therefore, finally, it will make: the tube expanding section of the copper tube that needs to be expanded is located between the liquid bags in the liquid bag type tube expanding units 209 that are closest and farthest from the connecting rod 208;

[0065] Then, the hydraulic system communicating with the connecting rod 208 supplies hydraulic medium. The hydraulic medium flows into the liquid bags in each group of liquid bag type tube expanding units 209 successively through the first connecting hole and the second connecting hole, and the copper tube undergoes the first deformation through the liquid bags, as shown in the upper picture in Figure 12 ;

[0066] Then, the hydraulic medium flows back, and the linear module one operates to traction the tube expanding member 204 to retreat by L3. L3 refers to the distance between the liquid bags in two adjacent groups of liquid bag type tube expanding units 209;

[0067] Then, the hydraulic system communicating with the connecting rod 208 supplies hydraulic medium. The hydraulic medium flows into the liquid bags in each group of liquid bag type tube expanding units 209 successively through the first connecting hole and the second connecting hole, and the copper tube undergoes the second deformation through the liquid bags, as shown in the lower picture in Figure 12 ;

[0068] Then, the hydraulic medium flows back, and the linear module one tractions the tube expanding member 204 to reset, and the tube expanding is completed.

[0069] As shown in Figure 11As shown, in the prior art, the tube expansion of the copper tube is formed in one step. Most of the deformation generated during the tube expansion of the copper tube is concentrated at both ends of the expanded tube section, that is, at point a formed between the expanded tube section and the unexpanded tube section of the copper tube, resulting in point a being stretched too thin and its strength being reduced, affecting the overall performance of the copper tube. For the convenience of description, an extreme state is taken as an example: The deformation generated during the tube expansion of the copper tube is evenly concentrated at two points a, and the total amount of deformation is N1, and the deformation amount at each point a is N1 / 2;

[0070] As Figure 12 shown, in this solution, during the first deformation process of the copper tube, point b in the expanded tube section deforms, and point c does not deform. The deformation amount of b is evenly concentrated at two points d related to it. The total deformation amount of b is N2, and the deformation amount at each point d is N2 / 2;

[0071] Also, since the axial length of b is less than the axial length of the one-step tube expansion forming of the copper tube in the prior art, N2 is less than N1. Specifically, taking five groups of liquid bag type tube expansion units 209 as an example, at this time, the axial length of the liquid bag in each group of liquid bag type tube expansion units 209 is equal to one-ninth of the axial length of the one-step tube expansion forming of the copper tube in the prior art. Correspondingly, N2 is equal to one-ninth of N1. Therefore, the deformation amount at point d is equal to one-ninth of the deformation amount at point a;

[0072] During the second deformation process of the copper tube, point c deforms, and after the second deformation, the entire tube expansion of the copper tube is completed. At this time, the connection point formed between the expanded tube section and the unexpanded tube section where the copper tube expands is point e, and the deformation amount that occurs at point e is equal to the deformation amount at point d. That is to say, compared with the prior art, in this solution, the deformation amount at the connection between the expanded tube section and the unexpanded tube section of the copper tube is reduced by eight-ninths;

[0073] Generally speaking, compared with the prior art, this solution can reduce the thinning amount at the connection between the expanded tube section and the unexpanded tube section during the tube expansion of the copper tube, improve its strength, and is beneficial to the overall use of the copper tube.

[0074] In addition, during the first and second deformation processes of the above-mentioned copper tube, there is a limiting mechanism 300 to limit, to prevent the copper tube from undergoing excessive deformation;

[0075] In addition, during the second deformation process of the above-mentioned copper tube, when c is deformed, d at both ends of c will also be deformed. At this time, d is not stretched thinner, but pressed thicker, forming a circle of scar f between b and c. However, it is well known that the purpose of expansion between the copper tube and the fin in the heat exchanger is to make the copper tube and the fin in close and complete contact, which is conducive to heat conduction between the copper tube and the fin. In this solution, the copper tube is expanded, and close and complete contact between the copper tube and the fin is achieved, which fully realizes the purpose of expansion between the copper tube and the fin in the heat exchanger. The scar f does not affect the realization of this purpose. In addition, the existence of the scar f also increases the contact area between the copper tube at point f and the heat conduction medium (usually water) in the copper tube.

[0076] In summary, this solution can reduce the thinning amount of the connection between the expanded section and the unexpanded section during the copper tube expansion process, improve its strength, and be beneficial to the overall use of the copper tube, while fully achieving the purpose of expansion connection between the copper tube and the fin in the heat exchanger. The scar f formed can also increase the contact area between the copper tube at point f and the heat conduction medium in the copper tube.

[0077] like Figure 7 and Figure 8 As shown, the limiting mechanism 300 includes a guide post 301 vertically arranged on the base and two groups of limiting units 304 connected to the guide post 301, and the two groups of limiting units 304 are an upper limiting unit and a lower limiting unit respectively.

[0078] Specifically, the limiting unit 304 includes a main board 305 . The main board in the upper limiting unit is slidably connected to the guide post 301 . The upper limiting unit can move in the vertical direction. The main board in the lower limiting unit is fixedly connected to the guide post 301 .

[0079] The two groups of limiting units 304 are provided with limiting plates 306 on the facing surfaces of the main boards 305. The limiting plates 306 are provided with limiting grooves 307 running through the thickness thereof on the surfaces facing away from the main boards 305. Two groups of limiting grooves 307 are provided corresponding to the straight sections of the copper tubes.

[0080] The limiting plates 306 in each group of limiting units 304 are arranged in multiple groups along the axial array of the tube expansion element, and the gap between two adjacent groups of limiting plates 306 is used to avoid the fins.

[0081] The diameter of the limiting groove 307 matches the diameter of the copper tube after expansion.

[0082] The limiting groove 307 in the lower limiting unit is coaxially arranged with the tube expansion element.

[0083] When the copper tube and the fin are supported by the support mechanism 100, the fin is located in the gap between two adjacent sets of limiting plates 306. Then, the upper limiting unit moves downward, so that the limiting grooves 307 in the two sets of limiting units 304 form a complete circular groove. The circular groove coaxially surrounds the outer part of the straight tube section of the copper tube and its diameter matches the diameter of the copper tube after tube expansion. Its significance lies in restricting the copper tube from undergoing excessive deformation. After the tube expansion of the copper tube is completed, the upper limiting unit moves upward, and then the copper tube and the fin can be taken away from the support mechanism 100.

[0084] As Figure 7 shown, a vertically arranged second lead screw 303 is installed on the base. The second lead screw 303 is threadedly connected to the main board 305 in the upper limiting unit. The input end of the second lead screw 303 is power-connected to a third motor 302. By driving the second lead screw 303 to rotate through the third motor 302, the upper limiting unit can be moved in the vertical direction.

[0085] The working principle of the present invention:

[0086] Step 1: Support the copper tube through the support mechanism 100 and position the copper tube.

[0087] Step 2: The upper limiting unit moves downward and cooperates with the lower limiting unit to form a complete circular groove through their respective limiting grooves 307. The circular groove coaxially surrounds the outer part of the straight tube section of the copper tube and its diameter matches the diameter of the copper tube after tube expansion, restricting the copper tube from undergoing excessive deformation.

[0088] Step 3: The linear module one operates to traction the tube expansion member 204 to move towards the copper tube, so that the tube expansion member 204 extends into the straight tube section of the copper tube. The moving displacement of the tube expansion member 204 is equal to L1 + L2. L1 refers to the distance between the liquid bag in the liquid bag type tube expansion unit 209 that is farthest from the connecting rod 208 and the fin that is sleeved on the outer part of the copper tube and is closest to the pipe orifice of the straight tube section of the copper tube in the initial state. L2 refers to the distance between the fin that is sleeved on the outer part of the copper tube and is closest and farthest from the pipe orifice of the straight tube section of the copper tube, that is, the axial length of the tube expansion section that needs to be expanded in the copper tube. Therefore, finally, it will make: the tube expansion section of the copper tube that needs to be expanded is located between the liquid bags in the liquid bag type tube expansion units 209 that are closest and farthest from the connecting rod 208.

[0089] Step 4: The hydraulic system connected to the connecting rod 208 supplies a hydraulic medium. The hydraulic medium flows into the liquid bags in each group of liquid bag type tube expansion units 209 through the first connecting hole and the second connecting hole in sequence. The copper tube undergoes the first deformation through the liquid bags, as Figure 12 shown in the upper picture of

[0090] Step 5: The hydraulic medium flows back, and the linear module one operates to traction the tube expansion member 204 to retreat by L3. L3 refers to the distance between the liquid bags in two adjacent liquid bag type tube expansion units 209.

[0091] Step Six: The hydraulic system connected to the connecting rod 208 supplies hydraulic medium. The hydraulic medium flows into the liquid bags in each group of liquid bag type tube expanding units 209 successively through the first connecting hole and the second connecting hole, and causes the copper tube to undergo a second deformation through the liquid bags, as shown in the lower figure of Figure 12 the following figure;

[0092] Step Seven: The hydraulic medium flows back, and the linear module one pulls the tube expanding member 204 to reset, and the tube expanding is completed.

[0093] In a preferred embodiment, in this solution, by replacing the liquid bag type tube expanding units 209 with different liquid bag diameters, corresponding supporting plates can be added or reduced on the U-shaped supporting platform 101 and the straight tube supporting platform 102 of the supporting mechanism 100, and corresponding laminations 308 can be added or reduced in the limiting groove 307 to adapt to copper tubes with different pipe diameters and pipe lengths.

[0094] Specifically, as shown in Figure 10 , the laminations 308 are coaxially and detachably installed in the limiting groove 307. The laminations 308 are in the shape of semi-circular rings. There are multiple groups of laminations 308 and their inner and outer diameters decrease. By adding or reducing the corresponding number of laminations 308 in the limiting groove 307, the diameter of the finally formed circular groove can be made to correspond and match the diameter of the copper tube after tube expansion.

[0095] Similarly, a number of corresponding supporting plates are detachably installed on the U-shaped supporting platform 101 and the straight tube supporting platform 102. By adding or reducing the corresponding number of supporting plates, the final diameters of the U-shaped supporting platform 101 and the straight tube supporting platform 102 can be made to match the copper tube.

[0096] The laminations 308 and the supporting plates cooperate to replace the liquid bag type tube expanding units 209 with corresponding liquid bag diameters and liquid bag axial lengths to realize tube expansion of copper tubes with different pipe diameters. In addition, according to the pipe length of the copper tube, the size of the L1 value is recalculated, and tube expansion of copper tubes with different pipe diameters and pipe lengths can be realized.

[0097] After the above adjustments and debugging, the entire tube expanding device is adapted to the tube expansion of copper tubes with corresponding pipe diameters and pipe lengths, which can improve the tube expanding range of this tube expanding device. In addition, as is well known, production in factories is generally mass production, so the situation of continuously changing copper tubes will not occur. Therefore, the above adjustments and debugging are feasible to improve the tube expanding range of this tube expanding device.

[0098] Preferred embodiment. The reason why our country selects the liquid bag type tube expanding method to expand the copper tube fins in the heat exchanger is that the dimensional accuracy of domestic heat exchange copper tubes is relatively large, and the wall thickness deviation of the tubes can reach -10% to +10%. Therefore, in response to this situation, domestic researchers have developed the liquid bag type tube expanding technology. In the liquid bag type tube expanding technology, the positioning sleeve 207 is used for positioning between the tube expander and the copper tube. However, in the existing liquid bag type tube expanding technology, the positioning sleeve 207 is just a cylinder with a constant outer diameter, and the wall thickness deviation of the copper tube is relatively large, so the positioning effect is poor. Based on this, in this solution, the positioning sleeve 207 can adapt to copper tubes with different inner diameters to achieve the positioning between the tube expanding element and the copper tube. It can not only adapt to the wall thickness deviation of the copper tube, but also cooperate with the above adjustments and debugging to achieve the positioning of copper tubes with different pipe diameter specifications.

[0099] Specifically, as Figure 5 shown in Figure 6 Figure, the positioning sleeve 207 includes a movable sleeve 2071 and a fixed sleeve 2073.

[0100] An installation sleeve is installed on the mounting bracket 201. The movable sleeve 2071 is coaxially installed in the installation sleeve through a bearing. The movable sleeve 2071 is coaxially sleeved outside the connecting rod 208 through a bearing, and the movable sleeve 2071 can rotate around the axis.

[0101] The fixed sleeve 2073 is coaxially fixedly sleeved outside the connecting rod 208 and the fixed sleeve 2073 is located on the side of the movable sleeve 2071 facing the support mechanism 100. The fixed sleeve 2073 and the movable sleeve 2071 are in mutual contact.

[0102] A guide groove 2074 penetrating the inner and outer annular surfaces of the fixed sleeve 2073 is arranged along the radial direction on the end face of the fixed sleeve 2073 facing the movable sleeve 2071. A centering rod 2075 is slidably installed in the guide groove 2074.

[0103] A linkage member is arranged between the centering rod 2075 and the movable sleeve 2071. When the movable sleeve 2071 rotates, the centering rod 2075 is pulled to move along the guiding direction of the guide groove 2074 through the linkage member. Preferably, the linkage frame includes a linkage hole 2072 arranged on the movable sleeve 2071 and a linkage pin 2076 arranged on the centering rod 2075. The free end of the linkage pin 2076 slides in the linkage hole 2072, and when the movable sleeve 2071 rotates, the centering rod 2075 is driven to move along the guiding direction of the guide groove 2074 through the cooperation of the linkage hole 2072 and the linkage pin 2076.

[0104] Multiple groups of centering rods 2075 are arranged in an array along the circumferential direction of the fixed sleeve 2073. Preferably, at least three groups are arranged. When the movable sleeve 2071 rotates, multiple groups of centering rods 2075 move simultaneously and synchronously to achieve self-centering clamping of the inner wall of the copper tube nozzle.

[0105] As Figure 5 shown, a second motor 205 is installed on the mounting bracket 201. The output end of the second motor 205 is power-connected to the movable sleeve 2071 through a power transmission member 206. The movable sleeve 2071 is driven to rotate by the second motor 205. Additionally, it should be noted that during the tube expansion operation, the fixed sleeve 2073 and a part of the movable sleeve 2071 extend into the copper tube nozzle for self-centering internal clamping, but the part of the movable sleeve 2071 related to the power transmission member 206 does not extend into the copper tube nozzle.

[0106] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the technical solution content of the present invention, any brief modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A flaring method for a flaring device of a copper tube and a fin applicable to a reducing pipe, characterized in that: The expanding device for the copper tube and the fin applicable to the reducing pipe comprises a base, on which a supporting mechanism (100), an expanding pipe mechanism (200) and a limiting mechanism (300) are installed. The supporting mechanism (100) is used for supporting the copper tube and restricting and positioning the copper tube. The expanding pipe mechanism (200) is used for expanding the copper tube. The inner diameter of the limiting mechanism (300) matches the outer diameter of the copper tube after expansion and is used for restricting the copper tube from excessive expansion. The expanding pipe mechanism (200) and the limiting mechanism (300) cooperate to reduce the tensile thinning amount of the copper tube at point a, and point a refers to the connection between the expanded tube section where the copper tube is deformed and the unexpanded tube section where the copper tube is not deformed; The supporting mechanism (100) comprises a first support frame, a second support frame and a third support installed on the base. The upper end of the first support frame is provided with a U-shaped support table (101) for supporting the U-shaped section of the copper tube. The upper ends of the second support frame and the third support frame are both provided with straight pipe support tables (102) for supporting the free ends of the straight pipe sections of the copper tube; The expanding pipe mechanism (200) comprises a mounting frame (201) installed on the base. A linear module one for driving the mounting frame (201) to displace axially along the straight pipe section of the copper tube is arranged on the base. The upper end of the mounting frame (201) is provided with an expanding pipe member (204); The expanding pipe member (204) comprises a connecting rod (208) and a liquid bag type expanding pipe unit (209). The connecting rod (208) is installed on the mounting frame (201), and when the copper tube is supported by the supporting mechanism (100), the connecting rod (208) is coaxially arranged with the straight pipe section of the copper tube. There are several groups of liquid bag type expanding pipe units (209). The adjacent two groups of liquid bag type expanding pipe units (209) are coaxially detachably connected. After the multiple groups of liquid bag type expanding pipe units (209) are connected, an expanding pipe element is formed. One end of the expanding pipe element is coaxially detachably connected with the connecting rod (208), and a positioning sleeve (207) is coaxially installed outside the connecting rod (208); The liquid bag type expanding pipe units (209) in the expanding pipe element are communicated with each other. The connecting rod (208) is communicated with the expanding pipe element. The end of the connecting rod (208) is communicated with a hydraulic system, and the hydraulic system is used for providing hydraulic medium for the expanding pipe element; The expanding method comprises the following steps: Step 1: Support the copper tube by the supporting mechanism (100) and restrict and position the copper tube; Step 2: The upper limiting unit moves downwards and cooperates with the lower limiting unit to form a complete circular groove through their respective limiting grooves (307). The circular groove coaxially surrounds the outside of the straight pipe section of the copper tube and has a diameter matching the diameter of the copper tube after expansion to restrict the copper tube from excessive deformation; Step 3: The linear module one operates to pull the expanding pipe member (204) to move towards the copper tube, so that the expanding pipe member (204) extends into the straight pipe section of the copper tube. The moving displacement of the expanding pipe member (204) is equal to L1 + L2. L1 refers to the distance between the liquid bag in the liquid bag type expanding pipe unit (209) farthest from the connecting rod (208) and the fin sleeved outside the copper tube and closest to the pipe orifice of the straight pipe section of the copper tube in the initial state. L2 refers to the axial length of the expanding pipe section that needs to be expanded in the copper tube; Step 4: The hydraulic system supplies hydraulic medium, and the hydraulic medium flows into the liquid bags in each group of liquid-bag type tube expanding units (209), causing the copper tube to deform for the first time through the liquid bags. Step 5: The hydraulic medium flows back, and the linear module one operates to pull the tube expanding member (204) back by L3, where L3 refers to the distance between the liquid bags in two adjacent groups of liquid-bag type tube expanding units (209). Step 6: The hydraulic system supplies hydraulic medium, and the hydraulic medium flows into the liquid bags in each group of liquid-bag type tube expanding units (209), causing the copper tube to deform for the second time through the liquid bags. Step 7: The hydraulic medium flows back, and the linear module one pulls the tube expanding member (204) back to its original position, and the tube expanding is completed.

2. The expanding method of the expanding device for the expansion joint of copper tube and fin applicable to the reducing pipe according to claim 1, characterized in that: In the tube expanding element, the distance between the liquid bags in two adjacent groups of liquid-bag type tube expanding units (209) is equal to the axial length of the liquid bag itself.

3. The expanding method of the expanding device for the expansion joint of copper pipe and fin applicable to the reducing pipe according to claim 2, characterized in that: The limiting mechanism (300) includes a guide post (301) vertically arranged on the base and two groups of limiting units (304) connected to the guide post (301). The two groups of limiting units (304) are the upper limiting unit and the lower limiting unit respectively.

4. The expanding method of an expanding device for the expansion joint of a copper tube and fins applicable to a reducing pipe according to claim 3, characterized in that: The limiting unit (304) includes a main board (305). The main board in the upper limiting unit is slidably connected to the guide post (301), and the upper limiting unit can move in the vertical direction. The main board in the lower limiting unit is fixedly connected to the guide post (301). Limiting plates (306) are arranged on the opposite faces of the main boards (305) in the two groups of limiting units (304). The face of the limiting plate (306) facing away from the main board (305) is provided with limiting grooves (307) penetrating through its thickness. There are two groups of limiting grooves (307) corresponding to the straight pipe sections of the copper tube. The limiting plates (306) in each group of limiting units (304) are arranged in an axial array along the tube expanding element, and the gaps between two adjacent groups of limiting plates (306) are used to avoid the fins. The diameter of the limiting groove (307) matches the diameter of the copper tube after tube expanding, and the limiting groove (307) in the lower limiting unit is coaxially arranged with the tube expanding element.

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