CN116809785A - Pre-expansion device - Google Patents

Abstract

The invention discloses a pre-expansion device, which comprises a fixed sleeve internally provided with an installation cavity, wherein one end of the fixed sleeve along the axial direction is provided with a circular through hole; a pre-expansion piece is in clearance fit in the circular through hole; one end of the pre-expansion piece in the axial direction extends out of the fixed sleeve and is used for being inserted into an end hole of the copper pipe; a conical hole with gradually enlarged aperture is arranged in the other end of the pre-expansion piece along the axial direction; the pre-expansion piece comprises three pre-expansion modules which form a circumference along the circumferential direction, the three pre-expansion modules are arranged in a split mode, and one end of each pre-expansion module extending into the installation cavity along the axial direction is connected in the installation cavity in a sliding mode along the radial direction; the pre-expansion piece is provided with three pre-expansion modules which are mutually separated along the radial direction facing away from the circle center; and the three pre-expansion modules are mutually close to each other along the radial direction towards the center of the circle to an initial abutting state. According to the invention, only a manual hand is needed to insert the pre-expansion piece into the end hole of the copper pipe, other processing actions are not needed to be manually performed, the labor intensity of workers is low, and the production efficiency is high.

Description

Pre-expansion device

Technical Field

The invention relates to the technical field of shell and tube heat exchanger production, in particular to a pre-expansion device.

Background

The copper pipe is one of the component parts of the shell-and-tube heat exchanger, and the copper pipe needs to be subjected to pre-expansion treatment on the port of the copper pipe in the production process, so that the inner diameter of the end part of the copper pipe is enlarged and is larger than the inner diameters of other positions of the pipe part. Most of the existing pre-reaming work for the end part of the copper pipe is to insert the manual flaring device into the end part of the copper pipe by manual hand holding and pre-reaming the copper pipe by manual force applying on the manual flaring device; however, the existing hand-held manual expander has the defects of high labor intensity, high cost and low production efficiency in the process of pre-expanding the copper pipe.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the defects of high labor intensity, high labor cost and low production efficiency of workers in the process of pre-expanding the copper pipe in the prior art, thereby providing the pre-expanding device.

The invention provides a pre-expansion device, which is applied to pre-expansion processing of the end part of a copper pipe of a shell-and-tube heat exchanger, and comprises the following components:

the fixing sleeve is internally provided with an installation cavity, and one end of the fixing sleeve along the axial direction is provided with a circular through hole communicated with the installation cavity;

a pre-expansion piece which is in clearance fit in the circular through hole; one end of the pre-expansion piece in the axial direction extends out of the fixed sleeve and is used for being inserted into an end hole of the copper pipe; a conical hole is formed in one end of the pre-expansion piece, which faces the mounting cavity along the axial direction, and the aperture of the conical hole is gradually enlarged along the direction of the mounting cavity along the axial direction;

the pre-expansion piece comprises at least three pre-expansion modules which form a circumference along the circumferential direction, a plurality of pre-expansion modules are arranged in a split mode, and one end, facing the mounting cavity along the axial direction, of each pre-expansion module is connected in the mounting cavity in a sliding mode along the radial direction;

the annular elastic piece is embedded on the peripheral surface of the pre-expansion piece and is used for applying closing force towards the circle center along the radial direction to the pre-expansion piece;

the thimble is arranged in the mounting cavity and driven by the driving assembly to move along the axial direction, a conical part is arranged at one end of the thimble, which faces the pre-expansion piece along the axial direction, the taper of the conical part is matched with the taper of the conical hole, and the axial dimension of the thimble is larger than the depth of the conical hole;

the pre-expansion piece is provided with a plurality of pre-expansion modules which are pushed by the ejector pins to be in an expanding state of being separated from each other along the radial direction; and the pre-expansion modules are pushed by the annular elastic piece to be mutually close to an abutting initial state along the radial direction.

The pre-expansion device has at least the following technical effects: the method comprises the steps that a pre-expansion piece is split into at least three pre-expansion modules which are circumferentially arranged, one end of each pre-expansion module, which is positioned in a mounting cavity, is radially and slidably connected in the mounting cavity, and the inner diameter of a circular through hole is larger than the outer diameter of the pre-expansion piece in an initial state and the outer diameter of the pre-expansion piece in an expanding state; in the process of pre-reaming the end part of the copper pipe, an operator holds the pre-reaming device to insert a pre-reaming piece into an end hole of the copper pipe, and then starts a driving assembly to drive a thimble to gradually move along the axial direction towards the direction close to the pre-reaming piece, so that the outer wall of the conical part is attached to the inner wall of the conical hole to gradually push a plurality of pre-reaming modules to be separated from each other along the radial direction towards the direction deviating from the circle center, the outer diameter of the circumference formed by the expansion is expanded, and the pre-reaming of the end hole diameter of the copper pipe is realized; then, the driving assembly is started to drive the thimble to move and reset gradually along the axial direction far away from the pre-expansion piece, and in the process of axially moving and resetting the conical part, the elastic restoring force of the annular elastic piece gradually pushes the pre-expansion modules to approach to an initial state of mutual abutting along the radial direction towards the direction of the circle center at the same time so as to circularly perform pre-expansion processing on the end aperture of the other copper pipe through the actions; in the process of pre-expanding the end aperture of the copper pipe by using the pre-expanding device, the pre-expanding device is only needed to be manually held to insert the pre-expanding piece into the end aperture of the copper pipe, other processing actions are not needed to be manually performed, the labor intensity of workers is low, the pre-expanding cost is low, and the production efficiency is high.

Preferably, a circular boss is arranged on the outer peripheral surface of one end of the pre-expansion piece along the axial direction, the circular boss is parallel to the radial direction and is connected in the mounting cavity in a sliding manner along the radial direction, and a circular groove is circumferentially arranged on the outer peripheral surface of the circular boss; the annular elastic piece is embedded in the circular groove.

Preferably, a partition plate is arranged in the mounting cavity, the partition plate is used for axially dividing the mounting cavity into a limiting cavity and an assembling cavity from left to right, the thimble is arranged in the assembling cavity, a perforation is formed in the middle of the partition plate in an penetrating manner along the axial direction, and the perforation is used for the conical part to penetrate through; the axial dimension of the limiting cavity is matched with the axial thickness of the round boss, and the limiting cavity is used for limiting the round boss to move in the radial direction in the limiting cavity.

Preferably, a second through hole communicated with the mounting cavity is penetrated through one end of the fixing sleeve, which is axially away from the circular through hole, in the axial direction; the driving assembly comprises an oil cylinder which is axially arranged in the mounting cavity, and a piston rod of the oil cylinder is connected with the thimble; the oil cylinder is far away from one end of the thimble and penetrates through the second through hole to extend out of the fixed sleeve, and is connected with a hydraulic station, the hydraulic station is connected with a pedal reversing switch, and the pedal reversing switch is used for controlling the extension or contraction of a piston rod of the oil cylinder.

Preferably, a part of the oil cylinder extending out of the fixed sleeve is provided with a first connecting port and a second connecting port which are communicated with the inner cavity of the oil cylinder, and the first connecting port and the second connecting port are respectively communicated with the hydraulic station through a first telescopic hose and a second telescopic hose.

Preferably, a first internal thread is arranged on the inner wall of the second through hole, and a first external thread matched with the first internal thread is arranged on the outer circumferential surface of the oil cylinder; the oil cylinder is characterized in that a mounting hole is formed in one end, facing to a piston rod of the oil cylinder, of the thimble, a second internal thread is arranged in the mounting hole, and a second external thread matched with the second internal thread is arranged on the outer circumferential surface of the piston rod of the oil cylinder.

Preferably, the portion of the pre-expansion member extending to the outside of the fixing sleeve is provided as a multi-stage stepped portion, and the outer diameters of the multi-stage stepped portions are sequentially increased in the axial direction toward the mounting cavity.

Preferably, a transition sleeve is detachably connected between the fixing sleeve and the oil cylinder, the cross section of the inner surface of the fixing sleeve perpendicular to the axial direction is matched with the cross section of the outer surface of the transition sleeve perpendicular to the axial direction, and the cross section of the inner surface of the transition sleeve perpendicular to the axial direction is matched with the cross section of the outer surface of the oil cylinder perpendicular to the axial direction; a through groove is formed in the transition sleeve in an axial penetrating mode, and the through groove is used for accommodating the thimble.

Preferably, the outer circumferential surface of one end of the transition sleeve, which faces towards the fixed sleeve along the axial direction, is provided with a third external thread matched with the first internal thread; the inner wall of the through groove facing one end of the oil cylinder along the axial direction is provided with a third internal thread matched with the first external thread.

Preferably, the fixing sleeve is used for being manually held; the pre-expansion device further comprises a clamping assembly which is arranged separately from the fixed sleeve, and the clamping assembly is used for clamping and fixing the copper pipe; the clamping assembly comprises a fixing pipe which is axially arranged, the peripheral surface of the fixing pipe is axially provided with a plurality of spiral blades in sequence, and each spiral blade is provided with a plurality of inserting through holes for inserting and limiting a copper pipe; the fixed pipe is provided with a pipe circular plate along the axial direction towards one end of the pre-expansion piece, the position of each pipe circular plate corresponding to the insertion through holes is provided with an installation through hole in a penetrating mode along the axial direction, the installation through holes are used for embedding the end parts of the copper pipes, and the inner diameter of the installation through holes is larger than the outer diameter of the end parts of the copper pipes.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic perspective view of a pre-expansion device according to an embodiment of the present invention;

FIG. 2 is a schematic illustration of the hydraulic station and clamping assembly of an embodiment of the present invention;

FIG. 3 is a schematic perspective view of FIG. 2;

FIG. 4 is a schematic cross-sectional front view of the structure of FIG. 2;

FIG. 5 is an enlarged schematic view of FIG. 4 at A;

FIG. 6 is a schematic illustration of the construction of a pre-expander in an embodiment of the present invention;

fig. 7 is a schematic view of a structure in which a copper pipe is assembled to a clamping assembly according to an embodiment of the present invention;

fig. 8 is a schematic structural view of a clamping assembly according to an embodiment of the present invention.

Reference numerals illustrate:

1-copper pipe;

2-fixing sleeve, 21-mounting cavity, 211-limiting cavity, 212-assembling cavity, 213-clamping groove, 22-circular through hole, 23-partition plate and 231-perforation;

3-pre-expansion piece, 31-conical hole, 32-pre-expansion module, 33-round boss and 331-round groove;

4-a circular ring-shaped elastic member;

5-thimble, 51-cone part and 52-mounting hole;

6-oil cylinder, 61-piston rod, 611-second external screw thread, 62-first connecting port, 63-second connecting port, 64-first telescopic hose, 65-second telescopic hose, 66-first external screw thread;

7-hydraulic station, 71-pedal reversing switch;

8-a transition sleeve, 81-a through groove and 82-a third external thread;

9-clamping components, 91-fixed pipes, 92-spiral blades, 921-plug-in through holes, 93-pipe circular plates and 931-mounting through holes.

Detailed Description

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

As shown in fig. 2 to 6, the pre-expansion device provided in this embodiment is applied to pre-expansion processing of an end portion of a copper tube 1 of a shell-and-tube heat exchanger, where the pre-expansion device includes a fixed sleeve 2 with a mounting cavity 21 therein, and one end of the fixed sleeve 2 in an axial direction is provided with a circular through hole 22 communicating with the mounting cavity 21; a pre-expansion piece 3 is in clearance fit in the circular through hole 22; one end of the pre-expansion piece 3 in the axial direction extends out of the fixed sleeve 2 and is used for being inserted into an end hole of the copper pipe 1; a conical hole 31 is arranged in one end of the pre-expansion piece 3 facing the mounting cavity 21 along the axial direction, and the aperture of the conical hole 31 gradually expands along the axial direction towards the mounting cavity 21; the pre-expansion member 3 includes at least three pre-expansion modules 32 circumferentially forming a circle, in this embodiment, preferably, three pre-expansion modules 32 are separately disposed between the three pre-expansion modules 32, and one end of each pre-expansion module 32 facing the installation cavity 21 along the axial direction is slidably connected in the installation cavity 21 along the radial direction; the outer peripheral surface of the pre-expansion piece 3 is embedded with a circular ring-shaped elastic piece 4, and the circular ring-shaped elastic piece 4 is used for applying closing force towards the circle center along the radial direction to the pre-expansion piece 3; the installation cavity 21 is internally provided with a thimble 5 which is driven by a driving assembly to move along the axial direction, one end of the thimble 5, which faces the pre-expansion piece 3 along the axial direction, is provided with a conical part 51, the taper of the conical part 51 is matched with the taper of the conical hole 31, and the axial dimension of the thimble is larger than the depth of the conical hole 31; the pre-expansion piece 3 is provided with three expanding states that the pre-expansion modules 32 are pushed by the ejector pins 5 to be mutually separated along the radial direction facing away from the circle center; and the pre-expansion module 32 is pushed by the annular elastic piece 4 to approach to each other along the radial direction towards the center of the circle to be in an abutting initial state. It is understood that the axial direction of the present embodiment refers to the axial direction shown in fig. 4.

According to the pre-expansion device, the pre-expansion pieces 3 are arranged in a split mode to form three pre-expansion modules 32 which are circumferentially arranged, one end of each pre-expansion module 32 in the installation cavity 21 is connected in the installation cavity 21 in a sliding mode in the radial direction, and the inner diameter of the circular through hole 22 is larger than the outer diameter of the pre-expansion piece 3 in an initial state and is equal to the outer diameter of the pre-expansion piece 3 in an expanding state; in the process of pre-reaming the end part of the copper pipe 1, an operator holds the pre-reaming device in the embodiment to insert the pre-reaming piece 3 into an end hole of the copper pipe 1, then starts the driving assembly to drive the thimble 5 to gradually move along the axial direction towards the direction close to the pre-reaming piece 3, so that the outer wall of the conical part 51 is attached to the inner wall of the conical hole 31 to gradually push the three pre-reaming modules 32 to be separated from each other along the radial direction towards the direction away from the circle center, the outer diameter of the enclosed circumference is enlarged to enter the expanding state, in the process of switching the pre-reaming piece 3 from the initial state to the expanding state, the annular elastic piece 4 can gradually expand to generate larger elastic restoring force, and the annular elastic piece 4 can ensure that the pre-reaming piece 3 after being switched to the expanding state still maintains the circular cross-section shape, so that the accurate pre-reaming of the end hole of the copper pipe 1 is realized; then, the driving assembly is started to drive the thimble 5 to gradually move and reset along the axial direction towards the direction far away from the pre-expansion piece 3, and in the process of axially moving and resetting the conical part 51, the elastic restoring force of the annular elastic piece 4 gradually pushes the three pre-expansion modules 32 to be mutually close to an initial state of mutual abutting along the radial direction towards the circle center at the same time, so that the end aperture of the other copper pipe 1 is pre-expanded by the action in a circulating way; in the process of pre-expanding the end aperture of the copper pipe 1 by using the pre-expanding device of the embodiment, only the pre-expanding device of the embodiment is manually held to insert the pre-expanding piece 3 into the end aperture of the copper pipe 1, other processing actions are not needed to be manually performed, the labor intensity of workers is low, the pre-expanding cost is low, and the production efficiency is high.

It should be noted that, in a specific application, the radial dimension of the gap between the pre-expansion member 3 and the circular through hole 22 is matched with the expansion amount of the end hole of the copper pipe 1 to be pre-expanded, and the radial dimension of the gap between the pre-expansion member 3 and the circular through hole 22 may be reasonably increased or decreased according to the expansion amount of the end hole of the copper pipe 1 to be pre-expanded.

In particular, the annular elastic member 4 is preferably a single-turn circular arc spring. In other embodiments, the annular elastic member 4 may be made of an elastic material, such as spring steel.

As shown in fig. 4 to 6, in some embodiments of the present invention, a circular boss 33 is disposed on an outer circumferential surface of one end of the pre-expansion member 3 in the axial direction, the circular boss 33 is parallel to the radial direction and slidingly connected in the mounting cavity 21 in the radial direction, and a circular groove 331 is circumferentially disposed on the outer circumferential surface of the circular boss 33; the annular elastic member 4 is embedded in the circular groove 331. The circular groove 331 is used for limiting the circular elastic piece 4 axially, so that axial displacement of the circular elastic piece 4 relative to the pre-expansion piece 3 in the process that the pre-expansion piece 3 is switched from an initial state to an expanded state or in the process that the pre-expansion piece is restored to the initial state from the expanded state can be effectively avoided, the quality of pre-expanding the end aperture of the copper pipe 1 by expanding the pre-expansion piece 3 and the quality of restoring the pre-expansion piece 3 to the initial state can be ensured, and the end aperture of the other copper pipe 1 can be pre-expanded. Meanwhile, the annular elastic piece 4 is hidden in the mounting cavity 21, so that damage caused by impact of external force on the annular elastic piece 4 can be avoided, and the service life of the annular elastic piece is prolonged.

As shown in fig. 3 to 5, in some embodiments of the present invention, a partition plate 23 is disposed in the installation cavity 21, the partition plate 23 is used for dividing the installation cavity 21 into a limiting cavity 211 and an assembling cavity 212 from left to right along an axial direction, the thimble 5 is disposed in the assembling cavity 212, a through hole 231 is formed in a middle portion of the partition plate 23 along the axial direction, and the through hole 231 is used for the conical portion 51 to pass through; the axial dimension of the limiting cavity 211 is matched with the axial thickness of the circular boss 33, and the limiting cavity 211 is used for limiting the circular boss 33 to move radially in the limiting cavity 211. The part of the installation cavity 21 facing one end of the pre-expansion piece 3 along the axial direction is surrounded into a limiting cavity 211 through the partition plate 23, two surrounding walls of the limiting cavity 211 along the axial direction are respectively abutted against two side surfaces of the round boss 33 along the axial direction, and the round boss 33 can be axially limited, so that the pre-expansion piece 3 can be ensured not to generate axial displacement in the process of switching the pre-expansion piece 3 from an initial state to an expanded state or recovering the pre-expansion piece 3 from the expanded state to the initial state, the pre-expansion piece 3 can be ensured to expand the end aperture of the copper pipe 1, and the pre-expansion piece 3 is ensured to recover the end aperture of the other copper pipe 1 to be pre-expanded. It will be appreciated that the left and right orientations described in this embodiment are described based on the view angle shown in fig. 4.

Considering that the pre-expansion force applied to the end hole wall of the copper pipe 1 is required to be large enough to ensure the pre-expansion quality of the end hole wall of the copper pipe 1 in the process of pre-expanding the end hole wall of the copper pipe 1, as shown in fig. 1, 3 and 4, in some embodiments of the present invention, a second through hole communicated with the installation cavity 21 is penetrated through the end of the fixing sleeve 2 axially away from the circular through hole 22 in the axial direction; the driving assembly comprises an oil cylinder 6 axially arranged in the mounting cavity 21, and a piston rod 61 of the oil cylinder 6 is connected with the thimble 5; the oil cylinder 6 extends to the outside of the fixed sleeve 2 through the second through hole at one end deviating from the thimble 5, and is connected with a hydraulic station 7, the hydraulic station 7 is connected with a pedal reversing switch 71, and the pedal reversing switch 71 is used for controlling the extension or contraction of the piston rod 61 of the oil cylinder 6. In the process of pre-expanding the end aperture of the copper pipe 1, after an operator holds the pre-expanding device in the embodiment to insert the pre-expanding piece 3 into the end aperture of the copper pipe 1, the hydraulic station 7 can forward oil delivery into the oil cylinder 6 through stepping the pedal reversing switch 71, so that the piston rod 61 of the oil cylinder 6 extends out, and the force output by the piston rod 61 of the oil cylinder 6 is larger, so that larger pre-expanding force along the radial direction can be applied to the end aperture wall of the copper pipe 1 in the process of switching the pre-expanding piece 3 from an initial state to an expanding state, and the pre-expanding quality of the end aperture of the copper pipe 1 is ensured; after the pre-expansion processing is finished, the pedal reversing switch 71 is stepped on again, so that the hydraulic station 7 can reversely convey oil into the oil cylinder 6, the piston rod 61 of the oil cylinder 6 is contracted, the thimble 5 is driven to gradually move and reset along the axial direction towards the direction deviating from the pre-expansion piece 3, and simultaneously the three pre-expansion modules 32 gradually and simultaneously approach to an initial state of mutual abutting along the radial direction towards the center of a circle under the pushing of the elastic restoring force of the annular elastic piece 4, so that the end aperture of the other copper pipe 1 is pre-expanded by the action in a circulating way. In the whole pre-expansion processing process, an operator does not need to control the piston rod 61 of the oil cylinder 6 to stretch and retract by hand, so that the operator can stably hold the pre-expansion device of the embodiment to perform pre-expansion processing, and the pre-expansion quality is ensured. It should be noted that, in a specific application, according to actual needs, in other embodiments, the foot switch 71 may be a normally closed switch, and the foot switch 71 may extend the piston rod 61 of the oil cylinder 6, and when the foot switch 71 is not stepped, the piston rod 61 of the oil cylinder 6 is retracted.

In specific application, the drive assembly can be according to carrying out the required radial pre-expansion force's that exerts size in the pre-expansion process to the tip aperture of copper pipe 1 size reasonable choice, for example when the required pre-expansion force who exerts of pre-expanding to the tip aperture of copper pipe 1 is less, drive assembly is including following the axial and arranging electric telescopic handle in installation cavity 21, electric telescopic handle's flexible end is connected thimble 5, electric telescopic handle electricity is connected with the control switch that control electric telescopic handle's flexible end stretches out or contracts, control switch sets up the outer peripheral face of fixed cover 2. The electric telescopic rod is controlled by electric energy, is clean and clean, does not need to be provided with an additional power source relative to the oil cylinder 6 and the like, is more miniaturized, and is more convenient for operators to hold for pre-expansion processing.

As shown in fig. 1, 2 and 4, specifically, a portion of the cylinder 6 extending to the outside of the fixed sleeve 2 is provided with a first connection port 62 and a second connection port 63 communicating with the inner cavity thereof, and the first connection port 62 and the second connection port 63 communicate with the hydraulic station 7 through a first telescopic hose 64 and a second telescopic hose 65, respectively. When the pedal reversing switch 71 is stepped on for the first time, the piston rod 61 of the oil cylinder 6 is started to extend, oil is fed into the inner cavity of the oil cylinder 6 through the second telescopic hose 65, and oil is returned into the hydraulic station 7 through the first telescopic hose 64; when the pedal reversing switch 71 is stepped on again to start the piston rod 61 of the oil cylinder 6 to shrink, oil is fed into the inner cavity of the oil cylinder 6 through the first telescopic hose 64, and oil is returned into the hydraulic station 7 through the second telescopic hose 65; simultaneously, the telescopic characteristics of the first telescopic hose 64 and the second telescopic hose 65 are utilized, so that an operator can conveniently hold the pre-expanding device of the embodiment to move and pre-expand the end apertures of the plurality of copper tubes 1 which are clamped and fixed in a small range, and the processing efficiency is further improved.

As shown in fig. 3 and 4, in some embodiments of the present invention, a first internal thread is provided on an inner wall of the second through hole, and a first external thread 66 matching the first internal thread is provided on an outer circumferential surface of the cylinder 6; a mounting hole 52 is formed in one end of the thimble 5, which faces the piston rod 61 of the oil cylinder 6, a second internal thread is formed in the mounting hole 52, and a second external thread 611 matched with the second internal thread is formed on the outer circumferential surface of the piston rod 61 of the oil cylinder 6. The oil cylinder 6 is connected with the fixed sleeve 2 in a detachable mode of mutual screwing fit through the first internal thread and the first external thread 66, and the thimble 5 is detachably connected to the piston rod 61 of the oil cylinder 6 through mutual screwing fit of the second internal thread and the second external thread 611, so that on one hand, in the process of storing or transporting the pre-expansion device of the embodiment, each component part of the pre-expansion device can be detached, and the occupied space is reduced; on the other hand, the pre-expansion piece 3 and the thimble 5 can be detached together for maintenance, and the original pre-expansion piece 3 and the thimble 5 can be detached together for replacement into pre-expansion pieces 3 and thimble 5 with different sizes, so that the pre-expansion processing of the end hole diameters of copper pipes 1 with different sizes can be realized on the basis that only part of parts are required to be replaced, the cost is saved, and the application range is wide

Considering that the partition plate 23 for dividing the installation cavity 21 into the limiting cavity 211 and the assembling cavity 212 from left to right in the axial direction is arranged in the installation cavity 21, the partition plate 23 is used for limiting the freedom degree of the round boss 33 in the axial direction in the limiting cavity 211, in order to facilitate the disassembly of the pre-expansion piece 3 from the fixed sleeve 2 after the fixed sleeve 2 and the pre-expansion piece 3 are detached from the piston rod 61 of the oil cylinder 6, so as to maintain or replace the pre-expansion piece 3; as shown in fig. 4 and 5, in some embodiments of the present invention, a circumferential ring is provided on a surrounding wall of the mounting cavity 21 corresponding to the position of the partition plate 23, and a clamping groove 213 is provided on the surrounding wall, the dimension of the clamping groove 213 in the axial direction matches the thickness of the partition plate 23 in the axial direction, and the clamping groove 213 is used for embedding the partition plate 23. The partition plate 23 can be deformed and separated from the clamping groove 213 under the action of a large axial pulling force, and the pulling force is at least twice as large as the pushing force applied to the partition plate 23 along the axial direction by the pre-expansion module 32 in the process of pushing by the ejector pin 5 or pushing by the elastic restoring force of the annular elastic piece 4 along the radial direction.

As shown in fig. 4 to 6, in some embodiments of the present invention, the portion of the pre-expansion member 3 extending outside the fixing sleeve 2 is preferably provided as a three-stage stepped portion, the outer diameter of which increases in order in the axial direction toward the mounting chamber 21. The three-stage step part of the pre-expansion piece 3 in the initial state is provided with three sections with different outer diameters, and the three sections with different outer diameters can be respectively inserted into the end holes of the copper pipe 1 with the corresponding aperture for pre-expansion processing, so that the pre-expansion device in the embodiment can be used for pre-expanding the end holes of the copper pipe 1 with the same pre-expansion amount and three different apertures, and the application range is wider. In a specific application, the portion of the pre-expansion member 3 extending out of the fixing sleeve 2 may be configured as a second-stage step portion, a fourth-stage step portion, a fifth-stage step portion, and the like according to the axial dimension of the portion of the pre-expansion member 3 extending out of the fixing sleeve 2. The second-stage step part is a shaft shoulder, namely, the outer diameter of the shaft of the second-stage step part is changed once along the axial direction, and the shaft has two parts with different diameters; other multi-stage steps are also analogized to the above.

Considering that the outer diameter of the pre-expansion member 3 provided with the three-stage stepped portion is large, resulting in that the inner diameter of the fixing sleeve 2 for assembling the pre-expansion member 3 is large and larger than the outer diameter of the cylinder 6, in order to further reduce the weight of the pre-expansion device of the present embodiment, the operator can hold for pre-expansion processing; as shown in fig. 2 to 4, in some embodiments of the present invention, a transition sleeve 8 is detachably connected between the fixing sleeve 2 and the oil cylinder 6, the cross-sectional dimension of the inner surface of the fixing sleeve 2 perpendicular to the axial direction is matched with the cross-sectional dimension of the outer surface of the transition sleeve 8 perpendicular to the axial direction, and the cross-sectional dimension of the inner surface of the transition sleeve 8 perpendicular to the axial direction is matched with the cross-sectional dimension of the outer surface of the oil cylinder 6 perpendicular to the axial direction; a through groove 81 is formed in the transition sleeve 8 in a penetrating manner along the axial direction, and the through groove 81 is used for accommodating the thimble 5.

In this embodiment, the detachable connection structure of the transition sleeve 8 and the fixed sleeve 2 is not limited, and in order to ensure that the tightness of the connection between the transition sleeve 8 and the fixed sleeve 2 is improved on a detachable basis, as shown in fig. 3 and 4, a third external thread 82 matching with the first internal thread is provided on the outer circumferential surface of the end of the transition sleeve 8 facing the fixed sleeve 2 along the axial direction; of course, in other embodiments, the detachable connection structure of the transition sleeve 8 and the fixing sleeve 2 may be other structures such as a fastening structure of a fastening block and a fastening slot, or an interference fit structure of a fastening slot.

In this embodiment, the detachable connection structure of the transition sleeve 8 and the oil cylinder 6 is not limited, and in order to ensure that the tightness of the connection between the transition sleeve 8 and the oil cylinder 6 is improved on a detachable basis, as shown in fig. 4, an inner wall of the through groove 81 facing one end of the oil cylinder 6 along the axial direction is provided with a third internal thread matching the first external thread 66. Of course, in other embodiments, the detachable connection structure of the transition sleeve 8 and the oil cylinder 6 may be other structures such as a fastening block and a fastening slot that are fastened to each other or an interference fit that are inserted to each other.

As shown in fig. 1, 7 and 8, in some embodiments of the invention, the retaining sleeve 2 is configured for manual gripping; the pre-expansion device further comprises a clamping assembly 9 which is arranged separately from the fixed sleeve 2, and the clamping assembly 9 is used for clamping and fixing the copper pipe 1; the clamping assembly 9 comprises a fixing tube 91 which is axially arranged, ten spiral blades 92 are sequentially and axially arranged on the outer peripheral surface of the fixing tube 91, and a plurality of inserting through holes 921 for inserting and limiting the copper tube 1 are formed in each spiral blade 92; the fixed pipe 91 is provided with a pipe circular plate 93 along the axial direction towards one end of the pre-expansion piece 3, a mounting through hole 931 is formed on the pipe circular plate 93 corresponding to each insertion through hole 921 in a penetrating manner along the axial direction, the mounting through hole 931 is used for embedding the end part of the copper pipe 1, and the inner diameter of the mounting through hole 931 is larger than the outer diameter of the end part of the copper pipe 1. Considering that the length of the copper tube 1 is long, the present embodiment supports the copper tube 1 at different positions along the axial direction by ten helical blades 92, and ensures that the copper tube 1 inserted into the insertion through holes 921 on the ten helical blades 92 and located on the same line in the axial direction is always parallel to the axial direction, so that the pre-expansion member 3 pre-expands the end aperture of the copper tube 1. Meanwhile, the inner diameter of the mounting through hole 931 is set to be larger than the outer diameter of the end part of the copper pipe 1, so that interference on pre-expansion operation of the end hole diameter of the copper pipe 1 is avoided, and pre-expansion quality is improved. Specifically, the difference between the outer diameter of the end portion of the copper pipe 1 and the inner diameter of the installation through hole 931 and the difference between the outer diameter of the pre-expansion 3 in the initial state and the inner diameter of the circular through hole 22 are equal.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.

Claims (10)

1. A pre-expansion device for pre-expanding the end of a copper tube (1) of a shell-and-tube heat exchanger, characterized in that it comprises:

a mounting cavity (21) is formed in the fixing sleeve (2), and a circular through hole (22) communicated with the mounting cavity (21) is formed in one axial end of the fixing sleeve (2);

a pre-expander (3) clearance fitted in the circular through-hole (22); one end of the pre-expansion piece (3) in the axial direction extends out of the fixed sleeve (2) and is used for being inserted into an end hole of the copper pipe (1); a conical hole (31) is formed in one end of the pre-expansion piece (3) facing the mounting cavity (21) along the axial direction, and the aperture of the conical hole (31) is gradually enlarged along the axial direction towards the mounting cavity (21);

the pre-expansion piece (3) comprises at least three pre-expansion modules (32) which are circumferentially arranged in a split mode, wherein a plurality of the pre-expansion modules (32) are arranged in a split mode, and one end, axially facing the mounting cavity (21), of each pre-expansion module (32) is connected in the mounting cavity (21) in a sliding mode along the radial direction;

the annular elastic piece (4) is embedded on the outer peripheral surface of the pre-expansion piece (3), and the annular elastic piece (4) is used for applying closing force towards the circle center along the radial direction to the pre-expansion piece (3);

the thimble (5) is arranged in the mounting cavity (21) and driven by the driving assembly to move along the axial direction, a conical part (51) is arranged at one end of the thimble (5) facing the pre-expansion piece (3) along the axial direction, the taper of the conical part (51) is matched with the taper of the conical hole (31), and the axial dimension of the thimble is larger than the depth of the conical hole (31);

the pre-expansion piece (3) is provided with a plurality of pre-expansion modules (32) which are pushed by the ejector pins (5) to be in an expanding state of being separated from each other along the radial direction; and an initial state in which a plurality of the pre-expansion modules (32) are pushed to be radially close to each other to be abutted by the annular elastic piece (4).

2. A pre-expansion device according to claim 1, wherein a circular boss (33) is arranged on the outer peripheral surface of one end of the pre-expansion piece (3) along the axial direction, the circular boss (33) is parallel to the radial direction and is slidingly connected in the mounting cavity (21) along the radial direction, and a circular groove (331) is circumferentially and circumferentially arranged on the outer peripheral surface of the circular boss (33); the annular elastic piece (4) is embedded in the circular groove (331).

3. A pre-expansion device according to claim 2, wherein a partition plate (23) is arranged in the installation cavity (21), the partition plate (23) is used for dividing the installation cavity (21) into a limiting cavity (211) and an assembly cavity (212) from left to right along the axial direction, the thimble (5) is arranged in the assembly cavity (212), a through hole (231) is formed in the middle of the partition plate (23) along the axial direction in a penetrating way, and the through hole (231) is used for the conical part (51) to penetrate; the size of the limiting cavity (211) along the axial direction is matched with the thickness of the round boss (33) along the axial direction, and the limiting cavity is used for limiting the round boss (33) to move in the radial direction in the limiting cavity (211).

4. A pre-expansion device according to any one of claims 1-3, characterized in that the end of the fixed sleeve (2) axially facing away from the circular through hole (22) is axially perforated with a second through hole communicating with the mounting cavity (21); the driving assembly comprises an oil cylinder (6) axially arranged in the mounting cavity (21), and a piston rod (61) of the oil cylinder (6) is connected with the thimble (5); the oil cylinder (6) deviates from one end of the thimble (5) and passes through the second through hole to extend out of the fixed sleeve (2), and is connected with the hydraulic station (7), the hydraulic station (7) is connected with the pedal reversing switch (71), the pedal reversing switch (71) is used for controlling the piston rod (61) of the oil cylinder (6) to stretch out or shrink.

5. A pre-expansion device according to claim 4, characterized in that the part of the cylinder (6) extending outside the fixed sleeve (2) is provided with a first connection port (62) and a second connection port (63) for communicating with the inner cavity of the cylinder, and the first connection port (62) and the second connection port (63) are respectively communicated with the hydraulic station (7) through a first telescopic hose (64) and a second telescopic hose (65).

6. A pre-expansion device according to claim 4, characterized in that the inner wall of the second through hole is provided with a first internal thread, and the outer circumferential surface of the oil cylinder (6) is provided with a first external thread (66) matched with the first internal thread; an installation hole (52) is formed in one end, facing to a piston rod (61) of the oil cylinder (6), of the thimble (5), a second internal thread is arranged in the installation hole (52), and a second external thread (611) matched with the second internal thread is arranged on the outer circumferential surface of the piston rod (61) of the oil cylinder (6).

7. A pre-expansion device according to claim 6, characterized in that the portion of the pre-expansion member (3) extending outside the fixed sleeve (2) is provided as a multi-stage step, the outer diameter of which increases in sequence in the axial direction towards the mounting cavity (21).

8. A pre-expansion device according to claim 7, characterized in that a transition sleeve (8) is detachably connected between the fixed sleeve (2) and the oil cylinder (6), the cross-sectional dimension of the inner surface of the fixed sleeve (2) perpendicular to the axial direction is matched with the cross-sectional dimension of the outer surface of the transition sleeve (8) perpendicular to the axial direction, and the cross-sectional dimension of the inner surface of the transition sleeve (8) perpendicular to the axial direction is matched with the cross-sectional dimension of the outer surface of the oil cylinder (6) perpendicular to the axial direction; a through groove (81) is formed in the transition sleeve (8) in an axial penetrating mode, and the through groove (81) is used for accommodating the thimble (5).

9. A pre-expansion device according to claim 8, characterized in that the outer peripheral surface of the transition sleeve (8) axially facing one end of the fixed sleeve (2) is provided with a third external thread (82) matching the first internal thread; the inner wall of the through groove (81) facing one end of the oil cylinder (6) along the axial direction is provided with a third inner thread matched with the first outer thread (66).

10. A pre-expansion device according to claim 1, characterized in that the fixing sleeve (2) is intended for manual gripping; the pre-expansion device further comprises a clamping assembly (9) which is arranged separately from the fixed sleeve (2), and the clamping assembly (9) is used for clamping and fixing the copper pipe (1); the clamping assembly (9) comprises a fixing tube (91) which is axially arranged, a plurality of spiral blades (92) are sequentially arranged on the outer peripheral surface of the fixing tube (91) along the axial direction, and a plurality of inserting through holes (921) for inserting and limiting the copper tube (1) are formed in each spiral blade (92); the fixing tube (91) is provided with a tube circular plate (93) along the axial direction towards one end of the pre-expansion piece (3), the position of the tube circular plate (93) corresponding to each inserting through hole (921) is provided with a mounting through hole (931) in a penetrating mode along the axial direction, the mounting through holes (931) are used for embedding the end portions of the copper tubes (1), and the inner diameter of the mounting through holes (931) is larger than the outer diameter of the end portions of the copper tubes (1).