JPS63183734A - Tube expanding machine - Google Patents

Abstract

PURPOSE:To prevent a deformation of a mandrel so that an influence is not exerted on a stroke of a moving frame, by detecting a bend of the mandrel on the rear face of a mandrel supporting frame by utilizing the conductivity between the mandrel, and a conductive plate in the rear of the mandrel supporting frame. CONSTITUTION:In a position of a rear face supporting plate 103 of a mandrel supporting frame, a mandrel 10 is held in the center position of a mandrel passing hole by a guide bush 106 and an O-ring 107. When an abnormal force is applied to the mandrel 10, and the guide bush 106 is deflected in the diameter direction against the elasticity of the O-ring 107, a bend is generated in the mandrel 10, and the mandrel 10 comes into contact in a mandrel passing hole 110 of a conductive plate 109 provided in the rear of the supporting plate 103. By this contact, a current flows to an electric conduction detector from a power source, and the bend of the mandrel 10 is detected. At this time point, the mandrel 10 does not reach a permanent deformation, therefore, the permanent deformation of the mandrel 10 is prevented by suspending the tube expansion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pipe expanding machine that expands a plurality of pipes by simultaneously inserting a mandrel into each of the pipes. This kind of tube expander is
For example, it is used to manufacture cross-fin coils, which are a type of heat exchanger. Below, we will discuss the tube expander for producing cross-fin coils.

(Prior art) As shown in Fig. 7, a cross fin coil has a large number of transmissions in the longitudinal direction y and one to three transmissions in the middle direction 2 for a large number of fins F, F... Heat tube T.

The structure is such that T... is inserted through a skewer, and the number of heat exchanger tubes in the y direction is usually expressed in stages, and the number of heat exchanger tubes in two directions is usually expressed in rows.

Conventionally, such a loss fin coil has been provided with mandrels 10, 10, etc. at the same time in its heat transfer tubes T, T...
Insert the heat exchanger tubes T, T... at the same time to expand the fins F.
, F...

There are two types of pipe expanders used for this type of pipe expansion: vertical and horizontal.
Although there are different types, the basic structure is the same for all tube expanders.

The basic configuration will be explained with reference to FIGS. 5 and 6. A mandrel support frame 5 is provided at the front in the mandrel insertion direction on the base l, and a fixing frame 2 is provided at the rear. Between the mandrel support frame 5 and the fixed frame 2, there are left and right guide bars 4.
．． 4 is constructed, and a moving frame 8 is slidably attached to this. Between the mandrel support frame 5 and the moving frame 8, there are usually a plurality of intermediate plates 12. which are slidably supported on the guide bar 4.4. ．． 12□, 12. is provided.

A large number of mandrels 10 are arranged in parallel between guide bars 4, 4 depending on the number of stages and rows of cross-fin coil heat exchanger tubes, the base end of which is supported by a moving frame 8, and the middle part of the mandrel supporting frame 5 and intermediate plate 12. ．． 12. .

12, and a tube expansion head 18 (FIG. 7) is installed at the tip. A workpiece fixing means 19 is provided in front of the mandrel 10, and a cross fin coil 2, which is a workpiece, is attached to this.
1 is supported with the heat exchanger tube positioned on an extension of the mandrel 10. Then, by moving the movable frame 8 forward using a tube expansion cylinder 9 that is placed in the same stage as the fixed frame 2, the mandrels 10 are inserted into the heat transfer tubes all at once, and the tubes are expanded.

In the figure, X is the mandrel axis direction, Y is the mandrel stage direction,
2 represents the mandrel row direction.

[Problems to be Solved by the Invention] By the way, in such a tube expanding machine, a hard steel wire rod with a diameter of several millimeters is used as the mandrel 10, but the length is over 1 meter and it is extremely susceptible to deflection.

In addition, the cross fin coil 21 as a workpiece is
As described above, although the heat exchanger tube is set in a state where it is positioned on the mandrel axis by the work identification means 19, in reality, misalignment may occur between the heat exchanger tube and the mandrel 10. If this misalignment occurs, it not only causes buckling damage to the heat transfer tube during tube expansion and reduces product yield, but also applies a large force to the mandrel 10, and if a force exceeding the allowable stress is applied, the mandrel 10 recovers. Create impossible bends.

Against such deflection and bending of the mandrel 10,
A mandrel 10 is supported by a mandrel support frame 5, and a plurality of intermediate plates 1 are provided between the mandrel support frame 5 and the moving frame 8.
2. ．． 12. , x2s is installed, but if the intermediate plate is increased, it becomes difficult to secure the stroke of the moving frame 8 due to its thickness, and normally an intermediate plate is provided only at a rate of about 1 per 300H. In fact, such a spacing cannot prevent deformation of the mandrel 10.

The present invention was made in view of this situation, and provides a pipe expander equipped with a mandrel bending prevention mechanism that reliably prevents deformation of the mandrel and does not substantially affect the stroke of the moving frame. It is something.

[Means for solving problems]

The mandrel bending prevention mechanism, which is a main part of the pipe expander of the present invention, will be explained with reference to FIGS. 1 and 2 of the embodiment drawings.

1 is a cross-sectional view taken along line A--A in FIG. 5 and is a side view, and FIG. 2 is an enlarged view of section B in FIG. 1.

According to FIGS. 1 and 2, the mandrel 1111 hole 105 provided on the rear support plate 103 of the mandrel support frame 5
A conductive mandrel 10 is inserted between the inner circumferential surface of the passage hole through an elastic body 107 so as to be movable in the radial direction, and a conductive mandrel 10 is inserted adjacent to the rear support plate 103 at the rear of the rear support plate 103. Conductive plate 10 electrically insulated from rear plate 103
9 are arranged. The mandrel passage hole 110 provided in the conductive plate 109 has an inner diameter smaller than the maximum movable range of the mandrel 10 in the radial direction.
A power source is connected between G and the conductive plate 109 via an energization detector.

[For production]

In such a configuration, if a voltage is applied between the mandrel 10 and the conductive plate 109 by a power source, the mandrel 10 will be deflected in the radial direction against the elasticity of the elastic body 107 due to abnormal stress during tube expansion. When the conductive plate 109 is contacted, a current flows between the mandrel 10 and the conductive plate 109, and this is detected by the current detector. If the tube expansion is stopped immediately when the current is detected, permanent deformation of the mandrel 10 can be prevented.

When a normal force is applied to the mandrel 10, the self-centering action of the elastic body 107 holds the mandrel 10 at the center of the passage hole 105.

Also, during pipe expansion, as the movable frame 8 moves forward, the intermediate plates 121, 12-. 12i approaches the mandrel support frame 5. The situation will be explained with reference to FIG. 5. First, the movable frame 8 moves to the intermediate plate t2 in front of it. Then, the intermediate plates i2s and i2g sequentially contact the front intermediate plate t2. ．． t2.
Finally, the intermediate plate 121 at the rear of the mandrel support frame 5 comes into contact with the mandrel support frame 5.

The bending of the mandrel 10 occurs between two fulcrums, and the longer the distance between the fulcrums, the greater the deviation of the center portion. If you try to detect the bending of the mandrel 10 at the intermediate plate, it will be difficult to detect the bend when the movable frame 8 or the rear intermediate plate approaches or contacts this intermediate plate. At the rear support plate 103,
Since the intermediate plates approach each other at the end, a large distance between the supporting points remains until the end of the tube expansion, allowing highly accurate bend detection over the entire tube expansion period.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on embodiments shown in the drawings.The illustrated tube expanding machine is a horizontal type tube expanding machine for producing cross-fin coils.

First, the overall structure of the tube expander will be explained with reference to the plan view in FIG. 5 and the side view in FIG. There is one guide bar on each side between the fixed pillar 3.3 and the fixed column 4.3.
4 are spread horizontally.

The mandrel support frame 5 is movably supported in the forward direction by a guide bar 4.4 in order to flare the pipe end after the pipe is expanded, and horizontal screws 6.6, one each on the left and right, are attached to the mandrel support frame 5. The block 7 is rotated by a built-in motor (not shown) to move the block 7, which is screwed into the horizontal screw 6, back and forth.

Between the fixed frame 2 and the mandrel support frame 5, a movable frame 8 is supported by a guide bar 4.4 so as to be movable in the longitudinal direction, and the rod tip of a tube expansion cylinder 9 fixed to the rear surface of the fixed frame 2 is attached to the movable frame 8. The movable frame 8 is pivotally mounted to drive the movable frame 8 back and forth.

The horizontal screw 6 passes through the movable frame 8, and its tip is pivotally supported by the fixed frame 2 so as to be movable in the front and rear directions.

A plurality of intermediate plates 12 are provided between the mandrel support frame 5 and the moving frame 8. ．． 121, 128 are supported by the guide bar 4.4 so as to be movable in the front and rear direction, and the mandrel support frame 5 and the intermediate plate 12. between each intermediate plate and between the intermediate plates 12. and the movable frame 8 are connected to each other by a connecting frame 13 so as to be expandable and contractible.

A mandrel bending prevention mechanism 11 is attached to the rear surface of the mandrel support frame 5, and this will be explained in detail later with reference to a separate drawing.

In front of the mandrel support frame 5, a front frame 14 is supported by a guide bar 4.4 so as to be movable back and forth. This front frame 14 is mainly used for flaring, and the entire front frame 14 is moved forward and backward by a cylinder 17 fixed to the base 1.

The number of stages and rows of the mandrels 10, 10... are set according to the largest scale among the cross-fin coils to be processed, and each mandrel 10 has a movable frame 8 at its base end. The intermediate portion is supported by an intermediate plate 12. , i2g
, 12S mandrel support frame 5 and front frame 14, and is provided with a tube expansion head 18 (FIG. 7) at the tip.

A workpiece fixing means 19 is provided in front of the mandrel 10.10 on the base l, and the cross fin coil 21 before tube expansion is mounted on the installation stand 20 so that the heat transfer tube is an extension of the mandrel 10.10... Clamp from above and both sides so that it is located on the line. 22 is cross fin coil 2
1 cradle, and is configured to be moved forward and backward by a screw 23.

The above is the overall structure of the tube expander.

Next, the bending prevention mechanism 11 of the mandrel 10 will be explained in detail with reference to FIGS. 1 and 2.

The mandrel support frame 5 is a frame body with a similar cross-sectional shape, and has a window lot for allowing the mandrel 10 to pass through at the front and rear, and a front support plate 102 is fixed to the front surface, and a rear support plate 103 is fixed to the rear surface. .

The front support plate 102 has a mandrel passage hole 104 having a diameter slightly larger than the mandrel outer diameter on the reference passage line of the mandrel 10, and the rear support plate 103 has a mandrel passage hole 104 having a diameter slightly larger than the mandrel outer diameter.
Guide bushing 1 to mandrel passage hole 105 larger than 4
06 is fitted.

The guide bush 106 has a center hole with a diameter slightly larger than the outer diameter of the mandrel in order to support and pass the mandrel 10 therethrough, and its rear flange is locked to the rear surface of the rear support plate 103. In addition, a rubber O-ring 107 as an elastic body is fitted into two circumferential grooves formed in the outer garden.
The O-ring 107 and the guide bush 106 hold the mandrel 10 on its reference passing line, and are configured to allow deviation in the radial direction when an abnormal force is applied to the mandrel 10.

An insulating plate 108 is fixed to the rear support plate 103 from the rear. These insulating plates 10B are a set of two, with a conductive plate 10 between them.
9 is clamped to electrically insulate the conductive plate 109 from the mandrel support frame 5, while the guide bush 106 is not held in place. The conductive plate 109 is composed of a single copper plate or the like that is continuous in the mandrel stage direction Y, and connects all the mandrel I/Os.
A mandrel passage hole 110 is provided on the reference passage line. Both the passage hole of the insulating plate 108 and the passage hole l10 of the conductive plate 109 are set to a size that allows the radial deviation of the mandrel 10, but the mandrel passage hole 110 of the conductive plate 109 is larger than the passage hole of the insulating plate 10B. smaller, and when abnormal force is applied to mandrel 10, mandrel 1
0 comes into contact with the conductive plate 109 before permanent deformation occurs.

Although the power supply is not shown, one terminal is connected to the conductive plate 109 via a current detector such as a lamp or a buzzer, and the other terminal is connected to all the mandrels 10 in parallel.

Note that 111 is the intermediate plate 12. The intermediate support plate is provided in the mandrel and has a mandrel passage hole slightly larger than the outer diameter of the mandrel, and is connected to the mandrel support frame 5 by a connecting frame 13 so as to be movable in the front and rear direction.

Reference numeral 112 denotes a stripper attached to the front frame 14, through which the flare punch 113 is inserted in the front-rear direction, and further through which the mandrel 10 is inserted. The flare punch 113 is connected to the mandrel support frame 5 by a connecting frame 114.

The operation of the tube expander configured as described above will be explained next.

First, the cross fin coil 21 is fixed by the workpiece fixing means 19 with the movable frame 8 and the front frame 14 positioned at the backward limit. At this time, it goes without saying that the heat exchanger tubes of the cross fin coil 21 are positioned on the mandrel axis.

Next, from this state, the tube expansion cylinder 9 is driven to extend the rod.

As a result, the movable frame 8 moves forward, and the mandrels 10 are advanced all at once and inserted into the heat exchanger tube of the cross fin coil 21. On the other hand, as the movable frame 8 moves forward, the movable frame 8 comes into contact with the intermediate plate 123 in front of it, and then the movable frame 8 comes into contact with the intermediate plate 123 . Press to bring it into contact with the intermediate plate 12z in front of it.

In such a pipe expansion operation, when the mandrel 10 is advanced smoothly, the mandrel 10 is moved against the intermediate plate 12. ~
f2s and the front support plate 102, and furthermore, at the rear support plate 103, the guide bush 106 and the O
The ring 107 holds the mandrel at the center of the mandrel passage hole 105, preventing deflection as a whole and ensuring smooth advancement.

On the other hand, when an abnormal force is applied to the mandrel 10, the guide bushing 106 deviates in the radial direction against the elasticity of the O-ring 107, so that the front support plate 102 and the intermediate plate 12. The mandrel 10 is bent between the two, and the mandrel 10 comes into contact with the conductive plate 109. mandrel 10
FIG. 3 shows a state in which the conductive plate 109 is in contact with the conductive plate 109.

As a result of the mandrel 10 coming into contact with the conductive Fi 109, a current flows from the power supply to the energization detector, and the bending of the mandrel 10 is detected.At the time when zero bending is detected, the mandrel 10 has not yet reached permanent deformation, so at this point By stopping the tube expansion cylinder 9 and stopping tube expansion, permanent deformation of the mandrel 10 is prevented.

As described above, the intermediate plate 121 closest to the mandrel support frame 5 moves forward last, and depending on the movement stroke of the moving frame 8, it may not move forward, so the front support plate 102 and the intermediate plate 12° Between this, bending of the mandrel 10 is allowed until the end of tube expansion, and the bending of the mandrel 10 can be detected throughout the entire tube expansion period.

In addition, the front support plate 102 and the intermediate plate 12. is the original distance between the mandrel supports, that is, between the front support plate 102 and the rear support plate 103, or between the rear support plate 103 and the intermediate plate 12. The distance between the mandrel 10 and the mandrel 10 is large compared to each other, causing a significant radial deviation of the mandrel 10. This is effective in increasing the accuracy of detecting the bending of the mandrel 10.

When the tube expansion is completed, the moving frame 8 collides with the block 7.7, advances the horizontal screw 6.6, and slightly moves the mandrel support frame 8 forward. As a result, the flare punch 113 connected to the mandrel support frame 8 moves forward and is inserted into the tube end of the expanded heat exchanger tube, thereby performing flaring. This state is shown in FIG.

When the flaring process is completed, while the tube plate is held down by the stripper 112, the tube expansion cylinder 9 retracts the opening and the opening, and the movable frame 8 is moved back. As a result, the mandrel 10 is pulled out from the heat exchanger tube.

When the mandrel 10 is pulled out, the mandrel support frame 5
The front frame 14 returns to its original position, and the workpiece fixing means 1
All the work is completed by removing the cross fin coil 21 from 9.

〔Effect of the invention〕

As is clear from the above description, the pipe expander of the present invention detects mandrel bending on the rear surface of the mandrel support frame, prevents permanent deformation of the mandrel, suppresses the expense and decrease in work efficiency associated with mandrel replacement, and improves the quality of the product. This is highly effective in reducing costs.

Furthermore, the mandrel is reliably bent on the rear surface of the mandrel support frame, not only at the beginning of the pipe expansion, but also at the end of the pipe expansion when the mandrel is almost inserted into the workpiece. This makes it possible to prevent bending.

Further, the tube expander of the present invention utilizes the conductivity of the mandrel, and since a conductive material such as a steel wire is generally used as the mandrel, it has the advantage of being easy to implement and being inexpensive.

Furthermore, if an energization detector is attached to each mandrel, it is possible to identify a mandrel in which an abnormality has occurred.

[Brief explanation of the drawing]

1 to 6 show the structure of an example of a pipe expander embodying the present invention. 2 and 3 are enlarged views of part B in FIG. 1, FIG. 5 is a plan view, and FIG. 6 is a side view. Moreover, FIG. 7 is a perspective view schematically showing a cross fin coil. In the figure, 5: mandrel support frame, 8: moving frame, 10: mandrel, t2+, t2□, 12. : intermediate plate, 103: rear support plate, 105: mandrel passage i[L, 107: elastic body, io9: xi+i, 110: mandrel passage hole. Figure 7 Figure 2 Figure 3 vtJ

Claims (1)

[Claims] (1) Between the mandrels (10) arranged in multiple stages, the movable frame (8) that supports the base end of the mandrel (10), and the movable frame (8) and the mandrel support frame (5) in front of it. The intermediate plate (12) is arranged to be movable in the front and back direction, and while each mandrel (10) is supported by the mandrel support frame (5) and the intermediate frame (12), a plurality of tubes are moved by moving the moving frame (8) forward. In a tube expansion machine that expands a pipe by inserting the conductive mandrels (
10) is inserted between the inner circumferential surface of the passage hole through an elastic body (107) so as to be movable in the radial direction, and is adjacent to the rear support plate (103). A conductive plate (109) electrically insulated between the mandrels (109) is provided, and the mandrel passage hole (110) provided in the conductive plate (109) is set narrower than the maximum movable range in the radial direction of the mandrel (10). Then, the mandrel (10) and the conductive plate (1
09) A pipe expanding machine characterized in that a power source is connected between the energization detector and the energization detector.