Patent Grant
6904677
This application is based on Japanese Patent Application No. 2001-254498 filed on Aug. 24, 2001, the disclosure of which is incorporated herein by reference.
The present invention relates to a method of manufacturing a tube used for a heat exchanger such as a radiator and a water heater and an apparatus for manufacturing the tube.
According to a radiator for a vehicle disclosed in JP-A-6-159986, dents or projections (dimples) are formed on inside walls of tubes at least at portions other than longitudinal ends (header insertion portions) of the tubes. This improves a coefficient of heat transfer between fluid flowing through the tubes (e.g. cooling water and hot water) and the tubes. Further, this restricts gaps between the header insertion portions of the tube ends and insertion holes formed on header tanks from excessively increasing, thereby preventing defective brazing between the tubes and the header tanks.
With respect to a method of manufacturing the tube, a work in a form of band plate is pressed so that dimples are formed. Further, to deal with variation of length of the tubes, it is proposed to control the timing of feeding the work into a pressing device and the timing of operation of the pressing device so that portions where the dimples are formed can be changed. After the dimples are formed, the work is shaped into a tube by a shaping roller and thereafter cut into a predetermined length. In this method, however, the work is fed intermittently. Therefore, it is difficult to continuously form the dimples, resulting in low productivity and production rate.
On the other hand, it is proposed to use a roller shaping machine having a roller formed with dents or projections on its outer peripheral surfaces in order to continuously form dimples. The roller has a portion having the dents or projections for forming the dimples and a portion without having the dents or projections. By this, portions where the dimples are formed and portions where the dimples are not formed, which corresponds the header insertion portions, are formed at predetermined intervals. In this method, however, the roller needs to be exchanged with another roller whenever the length of the tubes is changed. Therefore, it is difficult to deal speedily with variations in the length of the tubes.
The present invention is made in view of the forgoing matters and it is an object of the present invention to provide a method of manufacturing tubes, which have a plurality of projections (dimples) projecting inwardly at portions other than predetermined portions, capable of dealing speedily with variations of length of the tubes and improving productivity.
It is another object of the present invention to provide an apparatus for manufacturing tubes, which have projections (dimples) projecting inwardly at portions other than predetermined portions, capable of improving productivity by dealing with variations of length of the tubes.
According to the present invention, a method of manufacturing tubes, each of which has a plurality of projections projecting inwardly at a portion other than a predetermined portion. includes pressing a work having a shape of band plate to form projections while the work is fed in its longitudinal direction, crushing a projection formed at a predetermined portion of the work to flatten the predetermined portion, and shaping the work into a tubular shape and cutting the work into predetermined lengths to form the tubes.
According to the method, the projections are formed continuously while the work is continuously fed. To contrast with a method of feeding the work intermittently, the projections can be formed continuously. Therefore, productivity and production rate of the tubes improve. In addition, by changing the portion to be crushed, the portions without having the projections, such as portions corresponding to ends of the tubes, can be changed easily. Therefore, the method can deal with variations of length of the tubes without exchanging a roller. Accordingly, the method of manufacturing the tubes of the present invention deals with tube length variations and improves productivity and production rate.
Alternatively, the method of manufacturing the tubes of the present invention includes a first step of pressing only a predetermined portion of the work to form a projection at the predetermined portion and a second step of shaping the work into a tube and cutting the work into a predetermined length. By this, it is possible to deal speedily with variations of length of the tubes without exchanging the roller. Accordingly, productivity and production rate improve, as compared with a method of feeding the work intermittently.
According to the present invention, an apparatus for manufacturing the tubes includes a first shaping device that forms projections on the work having a shape of band plate by pressing while the work is continuously fed in Its longitudinal direction, a second shaping device that flattens a predetermined portion of the work by crushing a projection formed at the predetermined portion, and a third shaping device that shapes the work into a tubular shape and cuts the work into hail predetermined lengths to form the tubes. The third shaping device is placed forward of the second shaping device In a feed direction of the work.
The apparatus can form the projections continuously while the work is continuously fed. In contrast with the method of feeding the work intermittently, productivity of tubes and production rate improve because the projections can be formed continuously. Further, portions without having the projections, such as portions corresponding to ends of tubes, can be easily changed by changing portions that are crushed by the second shaping device. Therefore, it is possible to deal with variations of length of tubes without exchanging a roller.
Alternatively, the apparatus for manufacturing the tubes of the present invention includes a first shaping device that forms projections at a predetermined portion of the work by pressing only the predetermined portion while the work is continuously fed in its longitudinal direction, and a second shaping device that shapes the work into a tube and cutting the work into a predetermined length. The second shaping device is placed forward of the first shaping device in the feed direction of the work. By this, it is not required to exchange a roller. Accordingly, productivity of the tubes and production rate improve.
Embodiments of the present invention will be described hereinafter with reference to the drawings.
[First Embodiment]
Tubes of the present invention are for example used for a radiator that is a kind of a heat exchanger performing heat exchange between a vehicular engine coolant and air.
Referring to
Header tanks (hereinafter, tanks) 130 are made of aluminum. The tanks 130 are located at the longitudinal ends of the tubes 110 to communicate with the tubes 110. One of the tank 130 (for example, left tank in
Next, the tubes (tube bodies) 110 will be described.
As shown in
The second side wall 111b is integrally formed and connected from the inside wall of the tube body 110. On the other hand, the first side wall 111a is not integrally connected from the inside wall of the tube wall 110 before the brazing because it is formed at the side of the plate member. After the brazing, the first side wall 111a is integrated with the inside wall of the tube body 110 by the brazing material.
The first side wall 111a is formed with first projections (contact claws) 113a. The first projections 113a project from a portion between the first side wall 111a and the connecting portion 111c to a side opposite to the connecting portion 111c with respect to the first side wall 111a (toward left bottom in FIG. 2). Similar to this, the second side wall 111b is formed with second projections (receiving claws) 113b. The second projections 113b project from a portion between the second side wall 111b and the connecting portion 111c to a side opposite to the connecting portion 111c with respect to the second side wall 111b (to right bottom in FIG. 2). The ends of the first projections 113a and the second projections 113b are in contact with the inside wall 110d opposing to the connecting portion 111c (the inside wall 110d is an inside wall located under the connecting portion 111c in FIG. 2). The connecting portion 111c is also in contact with the inside wall 110d.
Next, the method of manufacturing the tubes 110 and the radiator will be described.
A projection-forming device (first shaping device) 210 is a roller shaping device that shapes the work 10W while rotating. That is, the work 10W is pressed while continuously fed in its longitudinal direction (A1) so that the projections 110b are formed. The projection-forming device 210 includes a pair of projection-forming rollers 211, 212 that are arranged to sandwich the work 10W from both the surfaces.
As shown in
A projection-crushing device (second shaping device) 220 shown in
The projection-crushing roller 221 that is placed above the work 10W is formed with a pressing projection 221a for crushing the projections 110b. The pressing projection 221a is formed only at a predetermined area in the cylindrical surface of the projection-crushing roller 221. The projection-crushing roller 221 is electrically connected with a cutting device 230 (described later). The projection-crushing roller 221 rotates at a rate in accordance with length of the tubes 110 to be manufactured and crushes the projections formed at the predetermined portion by the pressing projection 221a.
Therefore, the projection-forming device 210 (projection-forming rollers 211, 212) and the projection-crushing roller 222 are operated by the same servomotor (driving device). Also, the projection-crushing device 221 is operated by another servomotor 223.
The tube 110 (work 10W) Is shaped Into a flat tube by a bending device (described later) 234 and cut into a predetermined length by the cutting device 230. A cutter 231 of the cutting device 230 is driven by a servomotor (driving device) 232 that Is electrically connected to the servomotor 223 of the projection-crushing roller 221, to rotate with the projection-crushing roller 221.
The projection-crushing device 220 (specially, the projection-crushing roller 221) and the cutting device 230 are controlled by a control unit 240.
As shown by a general box in
In the order from
(Inserting Step)
Next, operation of the tube manufacturing apparatus 200 and the method of manufacturing the tube of the embodiment will be described.
First, the projection-forming device 210 presses the work low while the work low continuously feeds in the longitudinal direction (A1), thereby forming the projections 110b. (First step) Next, the projection-crushing device 220 crushes the projections 110b formed at the predetermined portion, such as at the portion corresponding to the tank insertion portion 110a, thereby flattening the predetermined portion of the work 10W.
(Second Step)
Thereafter, the work 10W is shaped into a flat tube by the bending device 234 provided forward of the projection-crushing device 220 in the feed direction (A1) of the work l0W and cut into the predetermined length by the cutting device 230.
(Third Step)
After the tubes 110 are produced in this way, the tubes 110 and the fins 120 are alternately laminated, so the heat-exchanging core portion is assembled. Then, the tubes 110 and the fins 120 are compressed by using a tool such as a wire so that the tubes 110 and the fins 120 are press-contact to each other. (Temporary assembling step) After, the heat-exchanging core portion is joined with the tanks 130 by integrally brazing.
(Brazing Step)
Here, after the completion of the inserting step, the work 10W changes its shape from a state shown in
Next, features of the embodiment will be described.
After the projections 110b are formed, the projections 110b formed at the predetermined portion of the work 10W is crushed and the predetermined portion of the work 10W is flattened. Therefore, the projections 110b are continuously formed while the work 10W is continuously fed. In contrast with a case of feeding the work 10W intermittently, the projections 110b are formed continuously. Accordingly, productivity of the tubes 110 improves.
Also, because operation timing of the projection-crushing roller 221 is controlled, portions where the projections 110b are crushed can be changed. Therefore, the portions without having the projections 110b, for example, the portions corresponding to the tank insertion portions 110a, can be changed easily. Accordingly, it is possible to deal with variations of length of the tubes 110 without exchanging the rollers 211, 212.
In this way, the method of manufacturing the tubes and the tube manufacturing apparatus of the embodiment can deal with variations in tube length smoothly and improve productivity and production rate.
Also, the tube 110 of the embodiment is formed with the first projections 113a that project from the portion between the first side wall 111a and the connecting portion 111c to a side opposite to the connecting portion 111c with respect to the first side wall 111a. The groove portion 111 easily opens by the spring back force such that a width of the groove, that is, a distance between the first side wall 111a and the second side wall 111b (see FIG. 8A), increases. When the tubes 110 are compressed, the ends of the first projections 113a are brought into contact with the inside wall 110d first, as shown in FIG. 8B.
With this, reaction force against the compress force of the temporary assembling step exerts to the ends of the first projections 113a. Further, the ends of the first projections 113a are in contact with the inside wall 110d and fixed thereon. Therefore, a bending moment to reduce the width of the groove is exerted to the first side wall 111a and the connecting portion 111c. Accordingly, as the compression continues from the state shown in
That is, as the compression increases, the insertion portion 112 is automatically wrapped by the first side wall 111a and the second side wall 111b that construct the groove portion 111, so the insertion portion 112 is interposed in the groove portion 111. Further, the insertion portion 112 is securely interposed in the groove portion 111 such that the gap between the inside wall of the groove portion 111 and the insertion portion 112, especially, the gap δ (see
Further, the second side wall 111b is formed with the second projections 113b that project from the portion between the second side wall 111b and the connecting portion 111c to a side opposite to the connecting portion 111c with respect to the second side wall 111b. The ends of the second projections 113b are in contact with the inside wall 110d. Therefore, when the first side wall 111a approaches the insertion portion 112 and presses the insertion portion 112 toward the second side wall 111b, that is, when the compression increases from the state shown in
Therefore, the gap between the insertion portion 112 and the inside wall of the groove portion 111, especially the second side wall 111b, can be uniformed and the insertion portion 112 can be interposed in the groove portion 111.
[Second Embodiment]
In the first embodiment, the projection-forming device 210 is continuously driven with the feeding of the work 10W so that the projections 110b are continuously formed. Also, the projections formed at the predetermined portion of the work low are crushed to flatten the predetermined portion. In the second embodiment, only a predetermined of the work 10W other than a portion corresponding to the tank insertion portion 110a is pressed to form the projections 110b while the work 10W is continuously feed in its longitudinal direction. (First step) Then, the work 10W is shaped into a flat tube. Further, the work 10W (tube 110) is cut into a predetermined length.
(Second Step)
Specifically, when the portion of the work 10W that corresponds to the tank insertion portion 110a passes between the projection-forming rollers 211, 212 of the projection-forming device 210, the projection-forming roller 212 moves downwardly (in a direction denoted by an arrow A2′) and separates from the work 110W, as shown in FIG. 10B. Thus, the work low maintains the portion 110a′ corresponding to the tank insertion portion 110a flat.
Here, the projection-forming roller 212 is moved by a link mechanism 250 shown in FIG. 9. In
Numeral 224 denotes a driving-gear box for transmitting the rotation of a servomotor (not shown) to the projection-forming roller 211, 212 to rotate the rollers 211, 212. In the embodiment, the projection-forming rollers 211, 212 are linked to the driving-gear box 224 through joints 225 for allowing output shaft to off-center. The joints 225 offsets gaps between output shafts 225 of the driving-gear box 224 and the projection-forming rollers 211, 212 when the projection-forming roller 212 is moved.
Next, effects and advantages of the embodiment will be described.
The projections 110b are formed by pressing only the predetermined portion of the longitudinal work 10W, the predetermined portion corresponding to the portion other than the tank insertion portion 110a. Therefore, it is not required to exchange the roller 211, 212 when the length of the tubes 110 is changed. As compared with the method of feeding the work 10W intermittently, the productivity of the tubes 110 and the production rate improve.
According to the method and the apparatus for manufacturing the tubes 110 of the embodiment, it is possible to deal with variations of length of the tubes and improve the productivity and the production rate.
Here, only the projection-forming roller 212 is moved. It is also possible to move the projection-forming roller 211 with the projection-forming roller 212. The projection-forming roller 212 is moved downwardly (in the direction of A2′) and separated from the work 10W. Therefore, in a case that heights of the projections 110b are large, the work 10W may warp toward the projection-forming roller 212 (downwardly) when the projection-forming roller 212 separates from the work 10W. In such a case, a guide 226 can be provided for restricting the work 10W from warping toward the projection-forming roller 212 (downwardly), as shown in FIG. 11A.
Here, the guide 226, shown in
[Other Modified Embodiments]
In the first and the second embodiments, the first projections 113a and the second projections 113b are formed on the first side wall 111a and the second side wall 111b, respectively. At least the first side wall 111a requires the projections. Thus, it is possible to eliminate the second projections 113b.
In the first and the second embodiments, the present invention is employed to the tubes 110 of the radiator 100. However, the present invention is not limited to this, but can be employed to tubes (pipes) for other purposes. In addition, the cross-section of the tube 110 is not limited to the shape described in the above embodiments, but can be a simple elliptic shape or circular shape.
The tubes 110 can be joined by methods other than brazing. For example, the tubes 110 can be joined by electric welding, as an electro-resistance-welded tube. Further, in the above embodiments, the projections 110b are formed in a step shown in FIG. 6A. The present invention is not limited to this. For example, the projections 110b can be formed in a step shown in FIG. 6C.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5209800 | Spencer et al. | May 1993 | A |
| Number | Date | Country |
|---|---|---|
| 63-049303 | Mar 1988 | JP |
| 6-159986 | Jun 1994 | JP |
| WO9505571 | Feb 1995 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20040200070 A1 | Oct 2004 | US |
