JP2590568B2 - Metal tube inner and outer surface processing equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal pipe inner / outer surface processing apparatus for processing an inner surface and an outer surface of a metal tube into a desired shape.

[Prior Art] For example, metal tubes (copper tubes, aluminum tubes, etc.) used in heat exchangers have fins, spiral grooves, projections, etc. on the inner and outer surfaces to improve heat transfer. Some are formed.

By the way, conventionally, when a metal pipe is processed into such a shape, a method of giving a predetermined shape to the inner and outer surfaces of the metal pipe by rolling or the like has been adopted.

However, in the rolling method, for example, when rolling a spiral groove, the metal tube must be rotated,
For this reason, there was a drawback that long products could not be processed. However, recently, a processing machine having a plurality of rotating bodies that revolve around the axis of the metal pipe while being pressed against the outer surface of the metal pipe has been developed. It has become possible to process grooves and the like without rotating the metal pipe by using this processing machine.

[Problems to be Solved by the Invention] However, when the above-described processing machine is used, the center of revolution of the rotating body and the axis of the metal pipe are slightly displaced during the processing, and vibration is generated due to the misalignment. . This vibration increases rapidly as the rotating body revolves at a high speed, and a large load fluctuation acts on the bearing of the drive shaft that drives the rotating body to revolve, thereby significantly reducing the life of the bearing. Become. When the vibration increases, the surface pressure of the rotating body against the metal tube changes greatly. At this time, when the surface pressure becomes extremely high, the metal tube may adhere to the metal tube due to oil shortage.

For this reason, the revolution speed of the rotating body cannot be higher than a predetermined revolution speed, and the upper limit of the rolling efficiency has been limited.

The present invention has been made in view of the above circumstances, and reduces the influence of the displacement between the center of revolution of a rotating body and the axis of a metal pipe during processing, and enables the rotating body to revolve at a higher speed. It is an object of the present invention to provide a metal pipe inner / outer surface processing apparatus that can perform the processing.

Means for Solving the Problems In order to achieve the above object, the present invention provides a diameter reducing device for reducing the diameter of a metal tube, and the metal arranged downstream of the diameter reducing device and processed by the diameter reducing device. A metal pipe inner / outer surface processing machine for further imparting a predetermined shape to the inner and outer surfaces of the tube, wherein the diameter reducing device corresponds to a die pressed against the outer surface of the metal tube and the die inside the metal tube. A floating plug floating at a position, wherein the metal pipe inner and outer surface processing machine includes a plurality of rotating bodies pressed against the outer surface of the metal pipe,
A drive mechanism for revolving the plurality of rotating bodies around the metal pipe, and a mandrel rotatably connected to the floating plug and floating at a position corresponding to the plurality of rotating bodies inside the metal pipe. The drive mechanism is provided with a drive shaft rotatably supported by a magnetic bearing and revolvingly driving the plurality of rotating bodies. The drive shaft is formed in a cylindrical shape so that the metal tube can be inserted therein. The axis of the shaft coincides with the center of revolution of the rotating body.

[Operation] In the present invention, since the drive shaft is supported in a floating state by the magnetic force of the magnetic bearing, even if the center of revolution of the rotating body and the axis of the metal tube are misaligned, the amount of misalignment is the same. The drive shaft is displaced to absorb the displacement. For this reason, vibration accompanying misalignment is suppressed, and the rotating body can revolve at high speed.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In FIG. 1, 1 is a copper tube (metal tube), and 2 is a diameter reducing device for reducing the diameter of the copper tube 1.

As shown in FIG. 3, the diameter reducing device 2 includes a die 3 having a tapered hole 3a pressed against the copper tube 1, and a floating plug floating in the copper tube 1 at a position corresponding to the tapered hole 3a of the die 3. 4 is provided. As shown in FIGS. 4 (a) and 4 (b), the floating plug 4 has a large diameter portion 5 and a rod portion 6 having a smaller diameter than the large diameter portion 5 which are coaxially integrated via a tapered portion 7. It was formed. A communication hole 8 is formed in the plug 4 from the axial center of the end surface of the large diameter portion 5 to the outer peripheral surface of the rod portion 6. The communication hole 8 and the large diameter portion 5 are formed in the end surface of the large diameter portion 5. A communication groove 5a is formed to communicate with the outer peripheral surface of. A mandrel 10 is provided at the tip of the rod 6 of the plug 4 coaxially with the rod 6.

The mandrel 10 is formed in a cylindrical shape, and has a spiral groove 10a formed on an outer peripheral surface thereof. The mandrel 10 is rotatably supported by a support shaft 11 screwed to the shaft center from the distal end surface of the rod portion 6, and its axial position is regulated by a bearing member 12 provided on the support shaft 11. . That is, the bearing member 12 is
a and a bearing Be rotatably fitted to the support shaft 11 between the a and the end face of the mandrel 10.The magnets 13 and 13 are formed by an axial repulsive force. By receiving a force in the direction of the tip of the mandrel 10 (rightward in FIG. 3), the load on the bearing Be is reduced. Each magnet 13 is formed of a rare earth magnet such as Nd-Fe-B.

The position corresponding to the mandrel 10 is shown in FIGS.
As shown in the figure, a metal pipe inner / outer surface processing machine 20 is provided.

The metal tube inner / outer surface processing machine 20 includes the above-mentioned mandrel 10 as one of the constituent elements, and forms a spiral groove on the inner surface of the copper tube 1 in cooperation with the mandrel 10. Hereinafter, the metal pipe inner / outer surface processing machine 20 will be described.

In FIG. 1 and FIG. 3, reference numeral 21 denotes the copper tube 1 and the mandrel 10.
And 22 is a radial holding member for holding the radial force of the rolled ball 21.

A plurality of rolled balls 21 are arranged in a radial holding member 22, and the radial holding member 22 includes a first frame 23 and a second
Frame 24.

The radial holding member 22 includes an inner ring 25 made of a hard metal and an outer ring 26 that backs up the inner ring 25.

The first frame 23 and the second frame 24 have a large-diameter recess 23a for holding the radial holding member 22 by fitting the outer periphery of the radial holding member 22 at the same coaxial position. A large-diameter recess 24a is formed, and these large-diameter recesses 23a are formed.
Inside the large-diameter recess 24a are formed small-diameter recesses 23b and 24b coaxial with the large-diameter recess 23a and the large-diameter recess 24a. The small-diameter concave portion 23b and the small-diameter concave portion 24b are provided with a first axial holding member 27 and a second axial holding member 28 for regulating the axial position of the rolled ball 21, respectively. The axial holding members 27 and 28 are formed in an annular shape, and have an inner diameter sufficiently larger than the outer diameter of the copper tube 1 reduced in diameter by the diameter reducing device 2. In the first frame member 23, a through hole 23c having a diameter that is continuous with the inner peripheral surface of the first axial holding member 27 is formed inside the small-diameter concave portion 23b. The diameter reducing device 2 side is a diameter increasing surface 23d that expands in a tapered shape toward the diameter reducing device 2. On the other hand, inside the small diameter recess 24b of the second frame 24, a through hole 24c is formed coaxially with the small diameter recess 24b.
A shaping die 29 for adjusting the outer peripheral surface of the copper tube 1 rolled by the rolled ball 24 is fitted to 24c. The movement of the shaping dice 29 toward the rear side in the axial direction (the right side in the drawing) is restricted by a contact plate 65 described later.

The metal pipe inner / outer surface processing machine 20 is connected via a holder 30 to a drive shaft 41 of an electric motor (drive mechanism) 40 in a state where the axes thereof are aligned.

The holder 30 has a cylindrical sleeve 31 having an outer peripheral surface formed into a tapered shape, and an inner peripheral surface having a tapered shape conforming to the outer peripheral surface of the sleeve 31, and an external thread 32a is formed on the outer peripheral surface. Male screw member 32 for holding, and male screw member 32 for holding
To move the sleeve 32 inward of the male screw member 32 for holding, thereby reducing the inner diameter of the sleeve 32,
As a result, the first frame 23 and the second frame 24 are sleeved.
A nut 33 for fixing to the holding male screw member 32 via 31;
And a connecting member 34 for connecting the holding male screw member 32 to the drive shaft 41. The connecting member 34 is formed in a disk shape and has bolts 35 provided at equal intervals on the outer peripheral portion.
Is connected to the end face of the male screw member 32 for holding, and the center thereof has a tapered connection inner surface 34 for connection to the drive shaft 41.
a is formed.

The drive shaft 41 has a connection inner surface of the connection member 34 at the distal end thereof.
It has a tapered connecting outer surface 41a having a shape that matches 34a, and a male screw 41b is formed on the outer periphery of the distal end side of the connecting outer surface 41a. The connecting member 34 is fixed to the connecting outer surface 41a. Further, the drive shaft 41 has a connection outer surface 41.
A key 43 is provided on a, the rotation of the connecting member 34 is prevented, and an insertion hole 41c for inserting the copper tube 1 is formed in the axis of the key 43.

The electric motor 40 includes the drive shaft 41, the set screw 42, and the key 43, and is provided inside a cylindrical housing 44 forming an outer shape and a central portion of the housing 44 in the axial direction. And a rotary drive rotor 46 provided on the outer peripheral surface of the drive shaft 41 at a position corresponding to the rotary drive stator 45. The drive shaft 41 includes a first radial magnetic bearing 47 located on the front side in the axial direction of the rotary drive stator 46, and a second radial magnetic bearing 48 located on the rear side in the axial direction of the rotary drive stator 46. Further, a thrust magnetic bearing 49 located on the rear side of the second radial magnetic bearing 48 rotatably holds the housing 44. First and second
The radial magnetic bearings 47 and 48 are fixed to a cylindrical radial bearing permanent magnet 50 provided on the outer peripheral surface of the drive shaft 41 and an inner surface of the housing at a position corresponding to the radial bearing permanent magnet 50. A radial bearing electromagnet 51 that generates magnetism in a direction that generates a repulsive force with respect to the radial bearing permanent magnet 50 is provided. Meanwhile, thrust magnetic bearing
49 is a disk-shaped thrust bearing permanent magnet 52 provided on the outer peripheral surface of the drive shaft 41, and is fixed to the housing 44 via a fixing member 53 at a position sandwiching the plate surface of the thrust bearing permanent magnet 52. And a thrust bearing electromagnet 54 for generating a repulsive force in the axial direction with respect to the thrust bearing permanent magnet 53. A first dustproof mechanism 56 is provided on a front cover 55 at the front end of the housing 44, and a second dustproof mechanism 58 is provided on a rear cover 57 of the rear end of the housing 44.

As shown in FIG. 2, the first dustproof mechanism 56 includes a front cover.
A male ring 59 having a plurality of (two in this figure) annular ribs 59a formed on the outer peripheral surface and fitted to and fixed to the drive shaft 41 protruding from 55, and arranged at an outer peripheral position of the male ring 59 Then, a female ring 60 having an annular groove 60a formed so as to fit the rib 59a at a position corresponding to the rib 59a of the male ring 59, and the female ring 60 is fixed to the front cover 55 with bolts 61. A fixing ring 62 is provided.

Further, as shown in FIG. 1, the second dustproof mechanism 58 has a disk body 63 in which a through hole 63a that fits around the rear end of the drive shaft 41 is formed. The body 63 has a plurality of annular grooves 63b formed in the through holes 63a.

In the drawing, reference numeral 44a denotes a hole for supplying a cooling gas into the housing 44, 64 denotes a nozzle for supplying lubricating oil to the rolled ball 21 portion, and 65 denotes a holder 30 of the metal pipe inner and outer surface processing machine 20.
This is the plate that regulates the amount that enters.

In the metal tube inner and outer surface processing apparatus configured as described above, when the drive shaft 41 rotates, by the drive shaft 41,
The metal pipe inner / outer surface processing machine 20 rotates. At this time, the copper tube 1 into which the floating plug 4 is inserted is inserted into the tapered hole of the die 3.
3a and the axial center of the metal pipe inner / outer surface processing machine 20 and pulling in the subsequent direction (rightward in FIG. 1), the tapered portion 7 of the floating plug 4 is held by the tapered hole 3a of the die 3 and The position of the plug 4 is determined, and the rolled ball 21 revolves around the outer periphery of the copper tube 1 corresponding to the mandrel 10. For this reason, the diameter of the copper tube 1 is reduced by the die 3 and the floating plug 4, and the copper tube 1 is pressed against the outer peripheral surface of the mandrel 10 by the rolled balls 21, whereby the inner peripheral surface of the copper tube 1 has a spiral shape. A groove is formed. Then, the outer peripheral surface of the copper tube 1 is neatly prepared by the forming die 39 located at the subsequent stage.

At this time, the mandrel 10 and the drive shaft 41 are pressed to the rear stage side by the force pulling the copper tube 1 to the rear stage side. At this time, the axial force applied to the mandrel 10 is held in a non-contact manner by the repulsive force of the magnets 13 of the bearing member 12. For this reason, the mandrel 10 can be used under a high rotation and a large load. Similarly, the drive shaft 41 is rotatably supported in a non-contact manner by the first radial magnetic bearing 47, the second radial magnetic bearing 48, and the thrust magnetic bearing 49. Becomes possible.

Also, in the rolling process, the shaft center of the copper tube 1 and the metal tube inner and outer surface processing machine
When the axis of the shaft 20 changes, a radial force acts on the drive shaft 41.In this case, the drive shaft 41 is displaced within the air gap of the radial magnetic bearings 47 and 48, and the inside of the metal pipe is displaced. Since the axis of the outer surface processing machine 20 automatically acts so as to coincide with the axis of the copper tube 1, vibration due to misalignment is suppressed. Therefore, the metal tube inner / outer surface processing machine 20 can be rotated at a high speed.

Therefore, according to the metal tube inner / outer surface machining apparatus configured as described above, the drive shaft 41 is connected to the first radial magnetic bearing 4.
7. Second radial magnetic bearing 48 and thrust magnetic bearing 4
Due to the holding, the drive shaft 41 can be semi-permanently rotated at a high speed and a high load without being worn by the bearing. In addition, the mandrel 10 can withstand high-speed and high-load because the axial force is received in a non-contact manner by using the repulsive force of the magnets 13 and 13.
Further, since the drive shaft 41 has the function of aligning the axes of the metal tube inner / outer surface processing machine 20 and the copper tube 1, vibration can be reduced. Therefore, there is a remarkable effect that the metal tube inner / outer surface processing machine 20 can be rotated at a higher speed than before.

Further, since the lubricating oil supplied in the copper pipe 1 is supplied to the mandrel 10 through the communication groove 5a and the communication hole 8 of the floating plug 4, the rolling by the mandrel 10 and the rotation of the mandrel 10 are performed smoothly. Will be able to Therefore, from this point, the metal pipe inner and outer surface
Can rotate at high speed.

Further, the cooling gas (for example, air) supplied into the housing 44 from the hole 44a passes through the outer peripheral surface of the drive shaft 41, passes through the annular rib 59a and the groove 60a of the first dustproof mechanism 56, or the second gas. The dust is discharged to the outside through the gap between the through hole 63a of the dustproof mechanism 58 and the drive shaft 41, and at this time, each part in the housing 44 can be cooled. Therefore, also from this point, the drive shaft 41 can be rotated with a high load.

Furthermore, the diameter reducing device 2 of the through hole 23c of the first frame 23
A diameter increasing surface whose side is tapered toward the diameter reducing device 2.
Since it is 23d, the lubricating oil is sucked by the movement of the copper tube 1 to the subsequent stage, and the lubrication of the rolled ball 21 is promoted.

In the above embodiment, the die 3 of the diameter reducing device 2 was used.
Although the diameter of the copper tube 1 is reduced by the tapered hole 3a, this die may be configured to reduce the diameter of the copper tube by a rotating body such as a rolling ball. In this case, it goes without saying that the rotating body as a die may be configured to revolve around the drive shaft supported by the magnetic bearing.

Although an example in which rolled balls are provided as a rotating body has been described, the rotating body may be formed in the shape of a roller. In this case, the outer periphery of the metal pipe is formed by grooves or irregularities formed on the outer peripheral surface of the roller. It can also be processed on the surface.

Needless to say, all of the rotating bodies may be configured to be revolved by a drive shaft supported by magnetic bearings.

Although an example in which rolled balls are provided as a rotating body has been described, the rotating body may be formed in the shape of a roller. In this case, the outer periphery of the metal pipe is formed by grooves or irregularities formed on the outer peripheral surface of the roller. It can also be processed on the surface.

[Experimental Example] An experiment was performed on the rolling speed by the metal tube inner and outer surface processing apparatus, and the results are shown below.

Experimental conditions (A) Dimensions of copper tube before rolling Outer diameter: 12.2 mm Thickness: 0.43 mm (B) Dimensions of copper tube after rolling Outer diameter: 9.60 mm Thickness: 0.30 mm Forming a spiral groove on the inner surface (c) In the conventional metal tube inner / outer surface processing apparatus, the drive shaft is rotatably supported by an angular bearing.

Experimental result As shown in the above table, the metal tube inner / outer surface machining apparatus of this embodiment can roll a copper tube at a speed about twice as fast as that of the conventional one.

[Effects of the Invention] As described above, according to the present invention, since the drive shaft is supported by the magnetic bearing in a non-contact manner, even if the center of revolution of the rotating body and the axis of the metal tube are displaced, the magnetic force is maintained. The drive shaft is displaced within the range of the air gap of the bearing, so that the revolution center of the rotating body coincides with the axis of the metal tube. For this reason, the vibration caused by the misalignment can be suppressed, and the mechanical loss caused by the conventional gear train is eliminated, so that the rotating body can revolve at a higher speed than before, and the efficiency of rolling the metal pipe can be improved. Can be improved.

[Brief description of the drawings]

1 to 4 are views showing an embodiment of the present invention. FIG. 1 is a sectional view of a metal pipe inner and outer surface processing apparatus, FIG. 2 is an enlarged sectional view of a main part of a first dustproof mechanism, FIG. 3 is a cross-sectional view of a die and a metal pipe inner and outer surface processing machine, FIG. 4 (a) is a front view of a floating plug and a mandrel, and FIG. 4 (b) is a left side view of the floating plug and a mandrel. 1 ... copper pipe (metal pipe), 2 ... diameter reduction device, 3 ... die, 4 ... floating plug, 10 ... mandrel, 20 ... metal pipe inner and outer surface processing machine, 21 ... rolled ball (rotation) ), 40 ... electric motor (drive mechanism), 41 ... drive shaft, 41 c ... insertion hole, 47 ... first radial magnetic bearing, 48 ... second radial magnetic bearing, 49 ... thrust magnetism bearing.

Claims (1)

(57) [Claims] 1. A diameter reducing device for reducing the diameter of a metal tube, and an inner and outer surface of a metal tube which is disposed at a subsequent stage of the diameter reducing device and further imparts a predetermined shape to the inner and outer surfaces of the metal tube processed by the diameter reducing device. A processing machine, wherein the diameter reducing device comprises a die pressed against the outer surface of the metal tube, and a floating plug floating at a position corresponding to the die inside the metal tube, and the inside and outside surface processing of the metal tube is performed. The machine includes a plurality of rotating bodies pressed against the outer surface of the metal pipe, a driving mechanism for revolving the plurality of rotating bodies around the metal pipe, and a rotating mechanism rotatably connected to the floating plug. And a mandrel floating at a position corresponding to the plurality of rotating bodies.The driving mechanism includes a drive shaft rotatably supported by a magnetic bearing and revolvingly driving the plurality of rotating bodies. Are forming the metal tube in the interior can be inserted as cylindrical, metal tube outer surface processing apparatus characterized by its axis is coincident to the center of revolution of the rotating body.