JPS5916534B2 - Hydraulic tube expansion jig for heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a jig for hydraulic tube expansion of a heat exchanger, and more specifically, a jig for expanding a heat exchanger tube by pressurizing a liquid, expanding the tube by the hydraulic pressure, and integrating it closely with a fin. o Regarding hydraulic pipe expansion jig.

When manufacturing heat exchangers used in air conditioners etc.
Generally, a large number of fins are inserted into the outer periphery of the heat exchange tube in advance, and the tube is expanded by applying hydraulic pressure such as water pressure or hydraulic pressure to the inside of the tube. By forcing a mandrel with a head and a hydraulic pressure means that is brought into close contact with the fins to form a heat exchanger into the tube, the tube is expanded and brought into close contact with the fins. The machine that was saved
Two methods have been adopted: mechanical and mechanical.

In the case of small-sized heat exchangers that are mass-produced locally, it is possible to mechanically expand the tubes using a special tube expansion device, which can amortize the equipment cost and is economically viable. In the case of heat exchangers that are only produced in small quantities, it is not possible to use mechanical tube expansion means due to economic reasons, and in this case, the heat exchange tubes are expanded using the hydraulic means described above. . 1.---Also, when the tube is expanded by hydraulic pressure, and the tube diameter is large and the distance between the tubes is large, a joint is directly connected to the opening side end of the tube, Although it is possible to apply hydraulic pressure into the tubes through the joints, it has been difficult to attach the joints to the ends of the tubes when the pitches of the tubes are small.

Conventionally, when the pitch of the tube is small, an inlet/outlet pipe, a header, etc. are installed at the open end of the tube, and then hydraulic pressure is applied to the tube via these headers.

However, in this case, the hydraulic pressure is normally 200 kg/(177
Therefore, the inlet/outlet pipes and the headers need to be thick enough to withstand the liquid pressure. etc. had to be used. The present invention was invented in view of the above points, and is a hydraulic tube expansion jig that can be set in a heat exchange tube and perform hydraulic tube expansion even if the pitch of the heat exchange tube is small or without installing an inlet/outlet tube. It has a shaft part that can be inserted into the inside of the end of the tube on one end side, a chuck fixing part with a screw on the outer surface of the intermediate part, and a pressing tool fixing part on the outer surface of the other end side. A hollow cylindrical jig main body, a cylindrical base having a screw on the inner surface that is screwed into the chuck fixing part of the jig main body, and a cylindrical base extending in the axial direction from the cylindrical base with a gap between them. It has multiple chuck pieces arranged in
In addition, each chuck piece forms a chuck made of an elastic material that can be bent inward in the radial direction, and the cylindrical base of the chuck is arranged such that the tip of the chuck piece is located on the shaft side of the jig main body. The chuck is fixed to the chuck fixing portion of the jig body with screws, and the chuck piece has an inclined outer surface that slopes radially outward toward the tip on the outer surface of the distal end of the chuck piece, and the distal end engages with the inclined outer surface of the chuck piece. a sleeve having an annular inclined surface and an inner diameter that can be slidably fitted over the chuck and the pressing tool fixing portion of the jig main body; A pressing tool is formed, which includes a plate body for pressing in the direction of the inclined outer surface of the chuck piece, and a pressing tool is provided on the plate body with a pivot part that pivots to the pressing tool fixing part of the jig main body, and the sleeve is pressed against the chuck piece. A cam surface is interposed between the inclined outer surface of the pressing tool and the pressing tool, and further includes a cam surface on the plate of the pressing tool, whose distance from the center of the pivoting portion increases as the pressing tool swings about the pivoting portion. The pivoting portion of the pressing tool is pivotally supported on the pressing tool fixing portion of the jig main body in a state where the cam surface can press the sleeve against the inclined outer surface of the chuck piece, and the swinging of the pressing tool By sliding the sleeve, the chuck piece is brought into pressure contact with the outer peripheral surface of the tube inserted into the shaft, the tube is fixed to the jig body, and liquid is supplied to the tube via the jig body. It is characterized in that the tube is expanded by press-fitting the tube.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The jig according to the present invention will be explained below with reference to embodiments of the drawings.

In the figure, reference numeral 1 denotes a jig main body in the shape of a circular rod, with a hydraulic pressure flow hole 11 formed through the longitudinal axis, and a heat exchange tube a, which will be described in detail later, at the tip of the main body 1. Shaft part 1 that can be inserted into
3, and the shaft portion 13 has a stepped portion 1 that can engage with two large and small diameter stepped portions B and c formed at the opening end of the tube a.
4 and 15, and an O-ring 16 is provided at the tip of the shaft portion 13.

Furthermore, a chuck 2, which will be described in detail later, is provided on the outer surface of the intermediate portion of the main body 1.
A chuck fixing part 17 to which a chuck can be attached is provided, and a screw 12 is formed around the chuck fixing part 17, and a pressing tool fixing part 18 is provided on the outer surface of the base of the main body 1 to attach a pressing tool 4, which will be described in detail later. Reference numeral 2 denotes a chuck, in which a plurality of chuck pieces 22 made of an elastic material capable of flexing inward in the radial direction extend in the axial direction from the cylindrical base 21 and form a cylindrical shape with gaps between them. A screw 23 is formed on the inner circumferential surface of the base portion 21 of the chuck 2, which can be screwed into the screw 12 of the chuck fixing portion 17 of the main body 1.

Furthermore, a clamping part 24 for clamping the tube a is provided at the tip of each chuck piece 22, and this clamping part 2
4, the small diameter stepped portion 1 of the shaft portion 13 in the main body 1
A locking surface 25 that locks the small-diameter step c of the tube a is formed opposite to the step 15, and the outer surface of the clamping portion 24 has a tip end that is connected to the shaft portion 13. This forms an inclined outer surface 26 that is inclined radially outwardly. The chuck 2 is integrally attached to the main body 1 by screwing the screw 23 of the base 21 into the screw 12 of the chuck fixing part 17 of the main body 1. At this time, the outer diameter of the chuck 2 is adjusted to the It is made to have approximately the same diameter as the base side of the main body 1, so that the outer circumferential surfaces of both are approximately flush with each other when attached.

Reference numeral 3 denotes a sleeve slidably fitted onto the main body 1 to cover the outer surface of the chuck 2, and a clamping portion 24 of the chuck piece 22 of the chuck 2 is provided on the inner surface of the distal end of the sleeve 3.
An inclined surface 31 that engages with the inclined outer surface 26 formed in The tube a is clamped and fixed between the portion 24 and the main body 1.

Reference numeral 4 denotes a pressing tool, and two parallel plates 4 are provided on both sides of one end of the arm rod 41 and slide against the other end of the sleeve 3 to press the sleeve 3 toward the inclined outer surface 26 of the chuck piece 22.
2 and 42 were attached together, and a pin 44 serving as a pivot to the pressing tool fixing part 18 was provided on the plates 42, 42, and the pressing tool fixing part 18 was inserted between the two plates 42, 42. In this state, the pressing tool 4 is pivotally attached to the pressing tool fixing part 18 via the pin 44, and the pressing tool 4 is pivoted to the plate bodies 42, 42 by swinging around the pin 44. Cam surface 4 whose distance from the center of the pin 44 increases
3, and by swinging each plate body 42 using the arm rod 41, the cam surface 4 of each plate body 42 is
3 is brought into sliding contact with the sleeve 3 so that the sleeve 3 is slid in the direction of the inclined outer surface 26 of the chuck piece 24.

Next, use the jig explained above to expand the heat exchanger into the fifth tube.
〜Explained based on FIG. 7. In each figure, a is a heat exchange tube bent into a U-shape, and the end of each inlet and outlet of the tube a is flared to braze the branch pipe h and the outlet pipe j, and a large diameter tube is formed. A step portion b and a small diameter step portion c are formed.

A plurality of tubes a are arranged in parallel, and tube sheets D and d are fitted to both ends thereof, and a large number of fins e are inserted and positioned in the tube a between the tube sheets D and d. and
The above-mentioned flare processing is performed after the parts are inserted and fitted in this manner.

The heat exchanger f is formed by expanding the tube a and the fin e using the jig described above and bringing them into close contact with each other. Further, in the figure, g indicates a flow divider 1 connected to the inlet side of each heat exchange tube a in the heat exchanger f through a flow divider pipe h, and a header connected to the outlet side of the tube a through an outlet pipe j. It is. The jig according to the present invention is used as follows.

First, the arm rod 41 of the pressing tool 4 is swung as shown by the solid line in FIG. 1 to open the chuck piece 22 of the chuck 2 outward in the radial direction. The processed heat exchange tube a is inserted into the heat exchange tube a until its small diameter stepped portion 15 is engaged with the small diameter stepped portion c of the tube a.

After this, the arm rod 41 of the pressing tool 4 is swung toward the main body 1 as shown by the imaginary line in the figure, and the cam surface 43 provided on the plate piece 42 of the pressing tool 4 causes the sleeve 3 to
is swung toward the tip side of the shaft portion 13 in the jig main body 1,
Along with this, the clamping part 24 of the chuck piece 22 of the chuck 2 is pushed radially inward by the tip inclined surface 31 of the sleeve 3, and the clamping part 24 pushes the tube a.
is pressed against the shaft portion 13 of the main body 1 to fix the tube a.

At this time, the locking surface 25 formed on the inner surface of the clamping portion 24 is locked to the small diameter step c of the tube a. In other words, the small diameter step c of the tube a is the small diameter step c of the shaft portion 13. The tube a is clamped by the step part 15 and the locking surface 25 of the clamping part 24, so that the tube a is not pulled out of the shaft part 13 due to hydraulic pressure or the like, and is held in a predetermined position. It is firmly fixed. After the jig is fixed to the tube a in this way, hydraulic pressure such as water pressure is applied to the tube a from the flow hole 11 of the main body 1 to expand the tube a and integrate it closely with the fin e. .

When performing this tube expansion, it may be performed for each tube a when the tube is in the hairpin type as shown in Fig. 6, or it may be performed for multiple tubes a at once. In this case, the jig is installed on the inlet and outlet sides of tube a, respectively, a hydraulic pump is connected to one jig side, and a shutoff valve is connected to the other jig side. .

In addition, when a flow divider g is connected to the inlet side of each tube a through a flow divider pipe h as shown in Fig. 7, the jig is attached only to the outlet side of each tube a. Then, a hydraulic pump is connected to the flow divider g, and a flow divider pipe having a separate shutoff valve is connected to each of the jigs, or a shutoff valve is connected to each side to expand the pipe.

In either case, the pipe expansion can be carried out using the above-mentioned jig of the present invention before brazing the outlet pipe to each of the tubes a. This eliminates the need to make the header thick enough to withstand the hydraulic pressure during hydraulic pipe expansion.

Furthermore, in the above-mentioned hydraulic pipe expansion, hydraulic pressure acts on the jig main body 1 of the jig and the tube a tries to be pulled out.
The step c of the tube a is the locking surface 25 of the chuck piece 22.
By engaging with the tube, it will not come out, and the sealing action of the O-ring 16 attached to the shaft portion 13 of the main body 1 will ensure that the tube can be expanded. After expanding the tube in this way, the arm rod 4 of the pressing tool 4 is swung as shown by the solid line in FIG. It is extracted from a.

After the above tube expansion is completed, a branch pipe h is fixed to the inlet side of the tube a, and an outlet pipe j is fixed to the outlet side thereof by brazing to each flared end. As explained above, according to the tube expansion jig of the present invention, the shaft portion of the jig body can be firmly and reliably fixed to the heat exchange tube with a simple operation. The tube can be fixed even if the pitch of the tube is small, and the inlet/outlet pipe, especially the outlet pipe and the header, can be expanded without having to be fixed to the tube in advance. There is no need to make it thick, and it can be made thin enough to withstand the refrigerant pressure as a heat exchanger.

Moreover, in the jig of the present invention, since the tube is strongly compressed by the shaft portion of the main body and the chuck piece of the chuck, the tube can be expanded reliably without being pulled out due to hydraulic pressure during tube expansion.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of the jig according to the present invention, FIG. 2 is a sectional view of the main part of the jig body, and FIG. 3 is a sectional view of the chuck.
Fig. 4 is a plan view thereof, Fig. 5 is an enlarged sectional view of the end of the heat exchange tube, Fig. 6 is a partially cutaway plan view of the heat exchanger to be expanded using the jig, and Fig. 7 is the heat exchanger. FIG. 1.゜゜゛゜Jig body, 2...Chick, 22
...chuck piece, 26...slanted outer surface,
3... Sleeve, 31... Inclined surface, 4
...Press tool, a...Heat exchange tube,
e...fin, f...heat exchanger.

Claims (1)

[Claims] 1 A hydraulic tube expansion jig that presses liquid into a heat exchange tube of a heat exchanger, expands the tube by the liquid pressure, and brings it into close contact with a fin, and has one end that can be inserted into the inside of the end of the tube. a hollow cylindrical jig main body having a shaft part, a chuck fixing part with a screw on the outer surface of the intermediate part, and a pressing tool fixing part on the outer surface of the other end, and an inner surface screwed into the chuck fixing part of the jig main body. It has a cylindrical base provided with a screw to tighten the cylindrical base, and a plurality of chuck pieces extending in the axial direction from the cylindrical base and arranged in a cylindrical shape with gaps between each other, and each chuck piece is radially inward. A chuck made of an elastic material that can be bent is formed, and the cylindrical base of the chuck is screwed to the chuck fixing part of the jig body so that the tip of the chuck piece is located on the shaft side of the jig body. the chuck piece has an annular inclined surface that engages with the inclined outer surface of the chuck piece; a sleeve having an inner diameter that can be slidably fitted over the chuck and the pressing tool fixing portion of the jig body; and a plate that slides against the other end of the sleeve and presses the sleeve toward the inclined outer surface of the chuck piece. Prepare your body,
and a pressing tool provided with a pivot part that is pivotally supported on the pressing tool fixing part of the jig main body is formed on this plate body, and the sleeve is interposed between the inclined outer surface of the chuck piece and the pressing tool. Further, the plate body of the pressing tool is provided with a cam surface whose distance from the center of the pressing tool increases when the pressing tool swings about the pivoting part, and the pivoting part of the pressing tool is connected to the cam surface. is pivoted to the pressing tool fixing part of the jig main body in a state where the sleeve can be pressed against the inclined outer surface of the chuck piece, and the swinging of the sleeve caused by the swinging of the pressing tool causes the chuck piece to be pressed against the inclined outer surface of the chuck piece. The tube is fixed to the jig body by being pressed against the outer peripheral surface of the tube inserted into the shaft of the jig body, and the tube is expanded by pressurizing liquid into the tube through the jig body. A jig for hydraulic pipe expansion of a heat exchanger, characterized in that