JPH0698399B2 - L-bending device for heat exchanger - Google Patents

Description

TECHNICAL FIELD The present invention relates to an L-bending device for a heat exchanger that bends a cross fin type heat exchanger in an L shape in the longitudinal direction of the heat transfer tube.

[Conventional technology]

Recently, in an air conditioner or the like, a cross fin type heat exchanger in which one end in the longitudinal direction of the heat transfer tube is curved in an L shape is partially used in order to achieve both miniaturization and improvement of heat exchange efficiency.

To bend the cross fin type heat exchanger like this,
The manufacturing technique of a bend pipe as disclosed in Japanese Patent Laid-Open No. Sho 60-231527 has been conventionally used. That is, one end in the longitudinal direction of the heat transfer tube of the heat exchanger set on the base plate is gripped by the chuck, and in this state, the chuck is rotated coaxially with the bending die to the temporary base plate side, and the heat exchanger is moved to the outer peripheral surface of the bending die. Bend along.

[Problems to be Solved by the Invention]

However, the cross fin type heat exchanger is different from the tube alone,
The heat transfer tube has a structure in which a large number of thin fins penetrate through the skewer. In the conventional L-bending device that only applies the manufacturing technology of the bend tube, the fins are bent along with the bending of the heat exchanger. There is a problem that the surface is strongly pressed and fins often fall.

An object of the present invention is to solve this problem and to provide an L-bending device for a heat exchanger that stably secures a predetermined bending radius.

[Means for Solving the Problems]

As shown in FIG. 1 and FIG. 2, the first apparatus for L-bending of the present invention holds the base plate 2 and one end of the heat exchanger W set on the base plate 2 in the longitudinal direction of the heat transfer tube to the side opposite to the base plate. A chuck 14 that swivels to and a bending die 3 that is positioned inside the swivel arc of the chuck 14 and rotates coaxially with the chuck 14 are provided. The heat exchanger W is attached to the outer peripheral surface of the bending die 3 by swiveling the chuck 14. In an L-bending device for a heat exchanger that bends along a line, a pressing mechanism 19 that applies a pressing force in the longitudinal direction of the heat transfer tube to the heat exchanger W from the end opposite to the chuck, and heat exchange accompanying the turning of the chuck 14. And a control means for detecting the bending progress of the vessel W and controlling the pressing force based on the detected bending progress of the heat exchanger W.

The control device is, for example, a rotation angle detection unit of the bending die 3.
41, and a pressure command unit 42a that outputs a pressing force command signal according to the rotation angle of the bending die 3 based on the signal from the rotation angle detection.
And a pressure detection unit 43 for detecting the pressing force, and a control unit 42b for outputting a drive command signal to the pressing mechanism 19 so that the pressing force detection signal detected by the pressure detection unit 43 matches the pressing force command signal. With.

In the second device, the chuck 14 is provided so that its front end in the turning direction can be displaced inside the turning arc.

In the third device, the base plate 2 is provided so as to follow the movement of the heat exchanger W in the longitudinal direction of the heat pipe due to the bending thereof.

[Action]

In the first L-bending apparatus of the present invention, the chuck 14 rotates coaxially with the bending die 3 so that the heat exchanger W held by the chuck 14 is moved relative to the bending die 3 along the bending die surface. While being bent without movement, the heat exchanger W during the bending period is pressed by the pressing mechanism 19 from the side opposite to the chuck, so that the bent portion of the heat exchanger W receives a force in a direction away from the bending die, The fin deforming force that the heat exchanger W receives from the bending die 3 is reduced.

Therefore, the fin deforming force that the heat exchanger W receives from the bending die 3 is large at the start of bending when the pressing mechanism 19 is not provided,
After that, it gradually decreases as the bending progresses. If the pressing force is set in accordance with the fin deforming force at the start of bending, the pressing force becomes excessive at the stage where the bending progresses, the heat exchanger W floats up from the bending die 3, and there is a risk that a predetermined bending radius cannot be secured. Occurs.

In the first device, since the pressing force is controlled as the bending of the heat exchanger W progresses, such a risk is eliminated, and the deformation force is reduced and the bending radius is stably ensured during the entire bending period. Is planned.

Also, the heat transfer tube is straight before the start of bending. Therefore, the pressing force applied in the longitudinal direction of the heat transfer tube at the start of bending may cause the heat transfer tube to buckle.

In the second apparatus, if the front end of the chuck in the turning direction is displaced at least inside the turning arc at the start of bending, the pressing force applied at the start of bending surely contributes to the reduction of the deformation force.

The heat exchanger W moves in the longitudinal direction of the heat transfer tube according to the bending thereof, while the reaction force accompanying the bending of the heat exchanger W is received by the base plate 2. When the base plate 2 is fixed, the heat exchanger W slides on the base plate 2 to cause fin collapse.

In the third device, by causing the base plate 2 to follow the movement of the heat exchanger, this fin collapse due to the base plate 2 is prevented.

〔Example〕

Hereinafter, the L-bending apparatus of the present invention will be described in detail based on the embodiments shown in the drawings.

FIG. 1 is a perspective view showing the overall structure of the embodiment apparatus.

According to FIG. 1, a base plate 2 is provided on a pedestal 1 so as to be able to move forward and backward. In the front part of the gantry 1, a cylindrical bending die 3 is rotatably supported by a rotating shaft 4 with a gap substantially matching the thickness of the heat exchanger W, which is a workpiece, between the bending die 3 and the base plate 2. ing. The rotary shaft 4 has no movement other than rotation and has two gears 5 and 6.

The first gear 5 engages with a rack 7 movably provided in the front-rear direction on the gantry 1, and the rack 7 is driven by a cylinder 8 to rotate the rotary shaft 4. The second gear 6 engages with the rack 9 on the base plate 2 and moves the base plate 2 forward and backward in synchronization with the rotation of the rotating shaft 4. The second gear 6 also has substantially the same radius as the bending die 3 and
The base plate 2 is moved at a speed substantially the same as the peripheral speed of.

The bending die 3 includes a pair of left and right swing arms 10, 10 extending forward.
Is fixed, and a block 11 is fixed to the tip ends of the revolving arms 10, 10. A pair of left and right arms 12, 12 penetrating the block 11 in the front-rear direction is provided with a movable block 13 at the rear end.

A chuck 14 for gripping one end of the heat exchanger W in the longitudinal direction of the heat transfer tube.
Is rotatably supported behind the movable block 13 by a rotary shaft 15, while the movable block 13 is connected to rods of cylinders 17, 17 supported by a bracket 16. The connecting position of the rod is deviated to the front or the rear with respect to the rotation shaft 15, and therefore the cylinders 17 and 17 retract or extend the rod to rotate the chuck 14 in the direction shown in the drawing.

Reference numeral 18 denotes an air cylinder, which is provided to improve the curved shape by slightly pushing the heat exchanger W downward just before starting to bend it.

A pressing mechanism 19 is fixed to the upper surface of the rear portion of the base plate 2. The pressing mechanism 19 comprises a block 20 fixed to the upper surface of the base plate 2 and a cylinder 21 fixed to the rear surface of the block 20. The cylinder 21 has a rod 22 slidably passing through the block 20, and a push-fit is attached to the tip of the rod 21.
It is fixed to 23. Reference numeral 24 denotes a guide rod of a pusher 23, which slidably penetrates the block 20. 25 is a box that houses the control means of the pressing mechanism 19 and the like.

FIG. 3 exemplifies a concrete circuit of the control means of the pressing mechanism 19 shown in FIG. 2. The solid line is the pneumatic system provided in the control means of the pressing mechanism 19, and the broken line is the electric system for controlling the pneumatic system. Is shown.

According to FIG. 3, the air pressure source (not shown) is a filter 31,
It is connected to the inlet port of a first solenoid valve 33 for switching the cylinder forward and backward, a proportional control valve 34, and a second solenoid valve 35 for cylinder brake via a regulator 32. Also,
The air pressure from the air pressure source is supplied to drive the spool of the third solenoid valve 36 for proportional control switching.

The outlet port of the first solenoid valve 33 is connected to the inlet port of the third solenoid valve 36 and the rod side of the cylinder 21, and the outlet port of the proportional control valve 34 is further connected to the inlet port of the third solenoid valve 36. To be done. The outlet port of the third solenoid valve 36 is connected to the opposite rod side of the cylinder 21.

The cylinder 21 is provided in the pressing mechanism 19 shown in FIG. 1, and is provided with a brake 37 controlled by a second electromagnetic valve 35.

On the other hand, the rotary encoder 41, which is the rotation angle detector,
The bending die 3 is connected to the rotary shaft 4 of the bending die 3 shown in FIG.
The rotation angle detection signal is output to the pressing force command signal 42a and the sequencer 42 which is the control block 42b.

The sequencer 42 stores the relationship between the rotation angle (L bending angle) of the bending die 3 and the pressing force corresponding to the rotation angle (L bending angle) as shown in FIG. A detection signal corresponding to the pressing force is input from a pressure switch 43 as a pressure detection unit attached to the line.

The relationship between the rotation angle of the bending die 3 and the pressing force depends on the scale of the heat exchanger so that the fin deforming force of the heat exchanger is reduced from the bending die and the heat exchanger does not float up from the bending die during the bending process. It is appropriately set depending on the bending conditions, and normally, as shown in FIG. 4, the pressing force tends to gradually decrease as the bending progresses.

Then, the sequencer 42 instructs the pressing force corresponding to the rotation angle of the bending die based on the detection signal from the rotary encoder 41, compares this with the detection signal from the pressure switch 43, and the actual pressing force matches the instruction. To output the signal. The output signal of the sequencer 42 is input as a control signal to the proportional control valve 34 via the interface 44 and the D / A converter 45.

Next, the operation of the apparatus of the embodiment shown in FIG. 1 will be described with reference to FIG.

First, the heat exchanger W is placed on the base plate 2 with the longitudinal direction of the heat transfer tube being aligned with the front-back direction of the base plate.
Then, the front end of the heat exchanger W is fixed by the chuck 14.
When the front end of the heat exchanger W is fixed by the chuck 14, the cylinders 17 and 17 are driven to rotate the chuck 14 in the direction shown in the drawing so that the tip of the heat exchanger W is bent in the bending direction prior to bending. Let me slightly bend. Then, in this state, the cylinder 8 and the cylinder 21 are operated.

When the cylinder 8 operates, the operation is transmitted to the rotary shaft 4 via the rack 7 and the gear 5 to rotate the rotary shaft 4 in the illustrated direction. When the rotary shaft 4 rotates in the illustrated direction, the bending die 3 rotates and the chuck 14 fixed to the bending die 3 rotates coaxially with the bending die 3. The rotation of the rotating shaft 4 rotates the bending die 3 while being transmitted to the base plate 2 via the gear 6 and the rack 9,
Is moved forward at the same speed as the peripheral speed of the bending die 3.

Thus, in the heat exchanger W, the end portion in the longitudinal direction of the heat transfer tube is the bending die 3
The base plate 2 is curved along the outer peripheral surface of the heat exchanger W, and moves forward along with the forward movement of the heat exchanger W due to the curvature of the heat exchanger W to prevent the fins from collapsing due to the sliding between the heat exchanger W and the base plate 2.

On the other hand, the movement of the cylinder 21 extends the rod,
Push the heat exchanger W during bending from the rear side in the axial direction of the heat transfer tube.
Press at 23. The operation of the cylinder 21 will be described in detail with reference to FIG.

Prior to bending, the spool of the second solenoid valve 35 is moved to the left in the figure, and the brake 37 of the cylinder 21 is released to the first position.
The spool of the solenoid valve 33 and the spool of the third solenoid valve 36 are moved to the right in the figure. As a result, the air pressure on the rod side of the cylinder 21 is released, and the air pressure adjusted by the proportional control valve 34 is supplied to the non-rod side of the cylinder 21 through the third control valve 36.

When the bending is started, the rotation angle of the bending die 3 is detected by the rotary encoder 41, the supply pressure to the cylinder 21 is detected by the pressure switch 43, and the detected supply pressure is the bending pressure of the bending die 3. The proportional control valve 34 operates so as to have an appropriate pressure according to the rotation angle. Thus, the heat exchanger W receives the pressing force as shown in FIG. 4 from the rear during the bending period, and the contact pressure between the heat exchanger W and the bending die 3 is reduced,
The fins are prevented from collapsing, and the fins 3 are prevented from being lifted up from the bending die 3 to ensure a predetermined bending radius.

Further, at the beginning of bending, the heat exchanger W is not yet bent, and the pressing force of the cylinder 21 is directly received by the heat transfer tube in the axial direction, so that the heat transfer tube tends to buckle. First, since the tip of the heat exchanger W is bent inward in the bending direction, a large pressing force at the beginning of bending acts in the bending direction to effectively reduce the fin deforming force.

When the bending is completed, the spool of the first solenoid valve 33 is moved to the left in the figure, and the rod of the cylinder 21 is retracted. Then, all the first to third solenoid valves 33, 35, 36 are moved to the positions shown in the figure. Return and fix the rod of cylinder 21.

[Effects of the Invention] The first L-bending apparatus of the present invention applies a pressing force from the rear to a heat exchanger that is bent along a bending die to prevent the heat exchanger from being strongly pressed by the bending die, Not only can the fins of the exchanger be prevented from falling, but the pressing force acting from the rear on the heat exchanger during bending is controlled according to the progress of the bending process, so excessive pressing force is applied to the heat exchanger. Since it is prevented from being applied and the heat exchanger is prevented from rising from the bending die, a predetermined bending radius is stably secured.

In the second device, the front end of the chuck in the swirling direction is deviated to the inside of the swirling arc. Therefore, even if a large pressing force is applied to the heat exchanger at the start of bending, the pressing force acts in the bending direction and the buckling of the heat transfer tube occurs. There is no risk of damage to the fins, and the fin deformation force is reliably reduced, ensuring smooth bending.

The third device causes the base plate to move following the movement of the heat exchanger due to bending, and thus prevents the fin from collapsing due to sliding between the heat exchanger and the base plate.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mechanical component part of an example of an L bending apparatus embodying the present invention, FIG. 2 is a block diagram showing a control means of a pressing mechanism of the present invention apparatus, and FIG. 3 is the same control. FIG. 4 is a circuit diagram showing a concrete configuration example of the means, and FIG. 4 is a graph showing an appropriate relationship example between the bending angle and the pressing force. In the figure, 2: base plate, 3: bending die, 14: chuck, 19:
Pressing mechanism, 21: Cylinder, 41: Rotation angle detection part (rotary encoder), 42: Sequencer, 42a: Pressing force command part, 42b: Control part, 43: Pressure detection part (pressure switch).

Claims (4)

[Claims] 1. A base plate (2), a chuck (14) which grips one end of a heat exchanger (W) set on the base plate (W) in a longitudinal direction of a heat transfer tube and swivels to a side opposite to the base plate, and a chuck (14). ) And a bending die (3) which is located inside the turning arc and rotates coaxially with the chuck (14).
In an L-bending device for a heat exchanger that bends the heat exchanger (W) along the outer peripheral surface of the bending die (3) by turning the chuck (14), an anti-chuck to the heat exchanger (W) is provided. The pressing mechanism (19) for applying a pressing force in the longitudinal direction of the heat transfer tube from the side end, and the bending progress of the heat exchanger (W) accompanying the turning of the chuck (14) are detected, and the detected heat exchange L of a heat exchanger, comprising: a control means for controlling the pressing force based on the curved progress of the vessel W.
Bending device. 2. The control means responds to the rotation angle of the bending die (3) based on a rotation angle detecting portion (41) of the bending die (3) and a signal from the rotation angle detecting portion (41). A pressure command unit (42a) that outputs a pressing force command signal, a pressure detecting unit (43) that detects the pressing force, and a pressing force detection signal that the pressure detecting unit (43) detects are the pressing force command signals. A control unit (42) that outputs a drive command signal to the pressing mechanism (19) so that they coincide with each other.
b) is provided, The L bending apparatus of the heat exchanger according to claim 1 characterized by things. 3. The L-bending device for a heat exchanger according to claim 1, wherein the chuck (14) is provided so that its front end in the turning direction can be displaced inside the turning arc. 4. A pressing mechanism (19) is provided on a base plate (2), and the base plate (2) is configured to follow the longitudinal movement of the heat transfer tube due to the bending of the heat exchanger. The L-bending device for a heat exchanger according to claim 1, wherein: