Protrusion forming device and method for forming protrusion part for heat exchanger

A protrusion forming device includes a holding portion holding an object that is be processed, a tool bit having a cutting portion capable of cutting an object held by a holding portion, and a drive portion capable of driving the tool bit. The tool bit is movable along a cut-in pathway so that the cutting portion is inserted into the object. The cutting portion is movable along a further-cut pathway so as to form a protrusion part that is cut in a linear shape and is connected to the object. The tool bit continuously contacts the protrusion part while moving along a forming pathway such that the protrusion part extends perpendicular to an outer surface of the object.

TECHNICAL FIELD

The present disclosure relates to a protrusion forming device and a method for forming a protrusion part for a heat exchanger.

BACKGROUND

A method is known, which is for forming a protrusion part connected to an object by cutting (i.e., shaping) the object without separating the protrusion part from the object. In shaping process, the protrusion part is generally shaped so as to be rolled back, in order to increase a cutting efficiency. For example, Patent Document 1 (JP 2009-32755 A corresponding to US 2009/0025222 A1) discloses a method for forming a platy heat radiation fin that is a protrusion part rolled back.

When the rolled-back protrusion part is used as a heat radiation fin, air between the radiation fins is difficult to be exchanged for outer air. Thus, a cooling capacity of the heat radiation fin may be relatively small.

SUMMARY

It is an objective of the present disclosure is to provide a protrusion forming device capable of forming a protrusion part extending perpendicular to an outer surface of an object, to provide a method for forming the protrusion part, and to provide a heat exchanger having the protrusion part formed by the protrusion forming device or the method for forming the protrusion part.

According to an aspect of the present disclosure, a protrusion forming device includes a holding portion, a tool bit and a drive portion. The holding portion holds an object that is to be processed, and the tool bit has a cutting portion capable of cutting the object. The tool bit is movable along a cut-in pathway intersecting with an outer surface of the object so that the cutting portion of the tool bit is inserted into the object. The cutting portion is inserted into the object is movable along a further-cut pathway parallel to the outer surface of the object so as to provide a protrusion part that is cut in a linear shape and is connected to the object. The tool bit continuously contacts the protrusion part while moving along a predetermined forming pathway such that the protrusion part extends perpendicular to the outer surface of the object.

According to another aspect of the present disclosure, a method is provided, which is for forming a protrusion part extending perpendicular to an outer surface of an object that is to be processed. According to the method, a tool bit is moved along a cut-in pathway intersecting with the outer surface of the object so that a cutting portion of the tool bit is inserted into the object. Moreover, the cutting portion inserted into the object is further moved along a further-cut process parallel to the outer surface of the object so as to form a protrusion part that is cut in a linear shape and is connected to the object. Furthermore, the tool bit is moved along a predetermined forming pathway while keeping the tool bit in contact with the protrusion part.

Accordingly, the protrusion part extending perpendicular to the outer surface of the object can be formed by cutting work. When the protrusion part extending perpendicular to the outer surface is used as a heat radiation fin, a high heat cooling capacity can be obtained.

In the present specification, a word “direction” includes a linear direction and a curved direction. Thus, the “direction intersecting with the protrusion part” includes a linear direction intersecting with the protrusion part perpendicularly, a linear direction inclined from a longitudinal direction of the protrusion part, and a circumferential direction of a circle that is drawn by using the base end portion of the protrusion part as a center of the circle.

DETAILED DESCRIPTION

First Embodiment

A protrusion forming device20according to a first embodiment of the present disclosure, shown inFIGS. 3 and 4, forms heat radiation fins12of a passage member10shown inFIG. 1. The passage member10used for a heat exchanger9may be a cylindrical hollow member, and has therein, for example, a passage11through which a cooling medium such as coolant is capable of flowing. Heat of the cooling medium in the passage11transfers to the passage member10to be radiated from the heat radiation fins12to ambient air. As shown inFIG. 2, the heat radiation fins12are needle-like protrusion parts that extend perpendicular to an outer surface13of the passage member10.

The protrusion forming device20will be described with reference toFIGS. 3 to 6. The protrusion forming device20includes a base30, a vise31, a drive portion and tool bits60. The drive portion includes an x-axis actuator40, a y-axis actuator50and an electronic control device70. The vise31may be used as an example of a holding portion which holds an object that is to be processed by the protrusion forming device.

The vise31is fixed on a board of the base30, and holds the passage member10that is used as an example of the processed object. The x-axis actuator40includes a slider41that is slidable in an x-axial direction parallel to a surface of the board of the base30. The x-axis actuator40is supported by a pole42to be fixed to the base30as shown inFIG. 4. The slider41is, for example, fixed to a ball screw that is provided rotatably in a case43. When the ball screw is rotary-driven by a motor44, the slider41can be moved in the x-axial direction. The passage member10is held by the vise31so that the outer surface13on an upper side of the passage member10becomes parallel to the x-axial direction. The passage member10is held by the vise31horizontally in the first embodiment, as shown inFIGS. 3 to 6.

The y-axis actuator50includes a slider51that is slidable in a y-axial direction perpendicular to the board surface of the base30. The slider51is, for example, fixed to a ball screw that is provided rotatably in a case52. When the ball screw is rotary-driven by a motor53, the slider51can be moved in the y-axial direction. The case52is fixed to and integrated with the slider41of the x-axis actuator40to be slidable in the x-axial direction together with the motion of the slider41in the x-axial direction.

Each tool bit60includes a support portion61and a cutting portion62that protrudes from one end part of the support portion61. The cutting portion62protrudes in a direction intersecting with a longitudinal direction of the support portion61. The cutting portion62is capable of cutting the passage member10. A rake angle θ of a rake face63of the cutting portion62is set larger than a rake angle of a rake face of a cutting portion of a general shaper used for cutting a flat surface. The rake angle θ is an angle of the rake face63with respect to a line perpendicular to the outer surface13of the passage member10as shown inFIG. 5.

The rake face63of the tool bit60has multiple grooves66that extend from an edge64toward a base end65of the tool bit60as shown inFIG. 5. The base end65is located at a connection portion between the cutting portion62and the support portion61. The grooves66are separated from one another in a width direction of the tool bit60, and are parallel to each other. The width direction of the tool bit60is perpendicular to the x-axial direction and the y-axial direction.

The other end parts of the support portions61of the tool bits60are connected to each other in the x-axial direction to be a cutting tool67having a platy shape. In the first embodiment, the cutting tool67is made of three tool bits60, for example.

The protrusion forming device20has a plurality of the cutting tools67arranged in the width direction of the tool bit60. In the first embodiment, the protrusion forming device20includes four cutting tools67, for example. As shown inFIG. 3, the cutting tools67are held by a chuck device71fixed to the slider51, so that the edges64of the tool bits60of one of the cutting tools67do not overlap the edges64of the tool bits60of another one of the cutting tools67in the width direction of the tool bits60, i.e., in an arrangement direction (thickness direction) of the cutting tools67.

The tool bits60move in the y-axial direction together with the slider51when the slider51moves in the y-axial direction. The tool bits60move in the x-axial direction together with the slider41and the y-axis actuator50when the slider41moves in the x-axial direction.

The electronic control device70has a microcomputer that includes a central processing unit (CPU), a read-only memory (ROM) and a random access memory (RAM). The electronic control device70operates the motors44and53based on a predetermined control program stored in the ROM to control a position of the tool bits60in the x-axial direction and the y-axial direction.

Specifically, the electronic control device70operates the motors44and53, thereby being capable of displacing the tool bits60along an approaching pathway K1, a cut-in pathway K2, a further-cut pathway K3and a first forming pathway K4. As shown inFIG. 5, the approaching pathway K1extends downward in a direction perpendicular to the outer surface13of the passage member10. An end point of the approaching pathway K1is located immediately above a position where the edge64of the tool bit60contacts the outer surface13.

As shown inFIG. 5, the end point of the approaching pathway K1is used as a start point of the cut-in pathway K2, and the cut-in pathway K2extends downward in a cut-in direction that is inclined at a predetermined angle (e.g., 10°) with respect to the outer surface13of the passage member10. An end point of the cut-in pathway K2is located inside the passage member10.

As shown inFIG. 5, the end point of the cut-in pathway K2is used as a start point of the further-cut pathway K3. The further-cut pathway K3extends along a direction parallel to the outer surface13of the passage member10, and extends along a direction from the base end65to the edge64of the tool bit60. An end point of the further-cut pathway K3is used as a start point of the first forming pathway K4, and the first forming pathway K4extends upward in the direction perpendicular to the outer surface13of the passage member10, as shown inFIG. 5. In other words, the first forming pathway K4extends in a direction away from the outer surface13of the passage member10.

Next, a method for forming the heat radiation fins12by using the protrusion forming device20will be described referring toFIGS. 7 to 11. As shown inFIG. 7, the method for forming the heat radiation fins12includes a cut-in step S1, a further-cut step S2and a forming step S3.

Firstly, at the cut-in step S1, the protrusion forming device20displaces the tool bits60along the approaching pathway K1as shown inFIG. 8, so that the edges64of the tool bits60become in the vicinity of the outer surface13of the passage member10. Subsequently, the protrusion forming device20displaces the tool bits60along the cut-in pathway K2as shown inFIG. 9, so that the edges64of the tool bits60are inserted into the passage member10. A cutting edge angle of the tool bits60with respect to the outer surface13is set at 10°, for example.

Next, at the further-cut step S2shown inFIG. 7, the protrusion forming device20displaces the tool bits60, which are inserted into the passage member10, along the further-cut pathway K3as shown inFIG. 10. Accordingly, linear cut parts14(protrusion parts) connected to the passage member10are provided. When the edges64of the tool bits60are located at the end point of the further-cut pathway K3, the cut parts14extend along the rake faces63of the tool bits60, and are not perpendicular to the outer surface13of the passage member10.

Next, at the forming step S3shown inFIG. 7, the protrusion forming device20displaces the tool bits60along the first forming pathway K4with the tool bits60kept in contact with the cut parts14, as shown inFIG. 11. At this step S3, the edges64of the tool bits60slide on base end portions of the cut parts14to bend the base end portions so that the cut parts14are formed to be the heat radiation fins12extending perpendicular to the outer surface13. The base end portion of the cut part14is directly connected to the outer surface13. The first forming pathway K4starts from a position adjacent to the base end portion of the cut part14.

As described above, the protrusion forming device20of the first embodiment includes the tool bits60, the x-axis actuator40, the y-axis actuator50and the electronic control device70. The electronic control device70is capable of operating the motor44of the x-axis actuator40and the motor53of the y-axis actuator50, and thereby displacing the tool bits60along the approaching pathway K1, the cut-in pathway K2, the further-cut pathway K3and the first forming pathway K4.

The electronic control device70displaces the tool bits60along the cut-in pathway K2so that the cutting portions62of the tool bits60are inserted into the passage member10. Next, the electronic control device70displaces the tool bits60, which are inserted into the passage member10, along the further-cut pathway K3so as to provide the linear cut parts14connected to the passage member10. Subsequently, the electronic control device70displaces the tool bits60along the first forming pathway K4with the tool bits60kept in contact with the cut parts14. Accordingly, the edges64of the tool bits60slide on and bend the base end portions of the cut parts14, so that the cut parts14can be formed to be the heat radiation fins12extending perpendicular to the outer surface13.

According to the protrusion forming device20and the protrusion forming method using the protrusion forming device20, the radiation fins12extending perpendicular to the outer surface13of the passage member10can be formed by cutting work. Therefore, the heat radiation fins12having a high cooling capacity can be obtained.

In the first embodiment, the rake face63of each tool bit60has the grooves66that extend from the edge64to the base end65of the tool bit60. Hence, it can be restricted that the cut parts14are bend in the width direction of the tool bit60. Therefore, the heat radiation fins12having a high cooling capacity can be obtained.

In the first embodiment, the passage member10may have the passage11through which a cooling medium is capable of flowing. The heat radiation fins12may radiate heat absorbed from the cooling medium through the passage member10. The passage member10may be used as the heat exchanger9. The heat radiation fins12may be used as a heat radiation portion in the heat exchanger9. Therefore, the heat exchanger9having a high cooing capacity can be obtained. The heat radiation fins12may be used as a heat absorption portion in the heat exchanger9.

Second Embodiment

A protrusion forming device according to a second embodiment of the present disclosure will be described with reference toFIG. 12. The protrusion forming device of the second embodiment includes a drive portion capable of displacing tool bits60along a second forming pathway K5. A start point of the second forming pathway K5is located at a position that is away from a base end portion of a cut part14(protrusion part), and is located between the base end portion and an edge portion of the cut part14as shown inFIG. 12. The second forming pathway K5extends in a circumferential direction of a circle that is drawn by using the base end portion of the cut part14as a center. In other words, the second forming pathway K5extends in a direction intersecting with the cut part14. When the tool bit60moves along the second forming pathway K5, the base end portion of the cut part14is pressed and bent so that the cut part14is formed to be the heat radiation fin12that extends perpendicular to an outer surface13of a passage member10.

In the second embodiment, effects similar to effects of the first embodiment can be obtained. Additionally, a curvature of the base end portion of the cut part14can be made to be gentle in the second embodiment. Therefore, it can be restricted that the cut part14breaks from its base end portion when the cut part14is bent and raised up.

Third Embodiment

A tool bit80of a protrusion forming device according to a third embodiment of the present disclosure will be described referring toFIG. 13. As shown inFIG. 13, a rake face81of the tool bit80has a curve surface84extending from an edge82of the tool bit80toward a base end83of the tool bit80in a direction away from the cut part14. Specifically, the curve surface84is protruded from the rake face81toward the cut part14, and an end part of the curve surface84is located at the edge82to contact the cut part14. The other end part of the curve surface84is distant from the cut part14.

In the third embodiment, effects similar to effects of the first embodiment can be obtained. Additionally, a contact area between the tool bit80and the cut part14is relatively small, and a bending moment applied on the cut part14can be made to be relatively small in the third embodiment. Therefore, the cut part14obtained by the cutting work can be made to be further linear, and a cooling capacity of a heat radiation fin12(cut part) can be increased.

Fourth Embodiment

A tool bit90of a protrusion forming device according to a fourth embodiment of the present disclosure will be described in reference toFIG. 14. As shown inFIG. 14, in the fourth embodiment, a rake face91of the tool bit90has a step surface94that extends from an edge94of the tool bit90toward a base end93of the tool bit90in a direction away from a cut part14. A part of the rake face91between the edge92and the step surface94contacts the cut part14, and the other part of the rake face91between the base end93and the step surface94is distant from the cut part14. Effects in the fourth embodiment are similar to those in the third embodiment.

Although the present disclosure has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. For example, the protrusion parts may be formed in a processed object other than the passage member10. The protrusion parts may be used for a purpose other than the heat radiation fins12. The passage member10may be held by the vise31without being located horizontally.

The further-cut pathway K3may extend in a direction other than the direction parallel to the outer surface13of the passage member10. The extending direction of the cut-in pathway K2may be inclined from the outer surface13at an angle other than 10°.

The forming pathway may extend in a direction other than the direction perpendicular to the outer surface13of the passage member10. The forming pathway may extend along a straight line perpendicular to the cut part14, or may extend along a straight line inclined from the cut part14.

A size of the tool bit60,80,90in its width direction may be enlarged, and the toll bit may form a protrusion part having a platy shape. The actuators40,50carrying the tool bit60,80,90are not limited to the actuators in that the ball screws are rotary-driven by using motors. Another known actuator may be used as the actuators40,50. In other words, an actuator capable of displacing the tool bit in a flat plane parallel to the x-axial direction and the y-axial direction can be used as the actuators40,50.

The drive portion may include, for example, mechanical components that do not require an electronic control, instead of the two actuators40,50and the electronic control device70.

In the first embodiment, the rake face63,81,91has three grooves which are parallel to each other. Here, the number of grooves may be one, two or four. Moreover, the grooves may not be parallel to each other.

The rake face63,81,91may not include the grooves. In the first embodiment, the three tool bits60,80,90are connected to each other integrally. Alternatively, one, two or four tool bits60,80,90may be connected to each other integrally.

The protrusion forming device may be configured to form a protrusion part by using a single tool bit60,80,90. The number of the cutting tools67made of multiple tool bits60,80,90may be equal to or lower than three, or may be equal to or higher than five.

The edges64,82,92of the tool bits60,80,90of one of the cutting tools67may overlap the edges64,82,92of the tool bits60,80,90of another one of the cutting tools67in the arrangement direction of the cutting tools67. The present disclosure is not limited to the above-described embodiments, and is feasible in various states without departing from the scope of the disclosure.

Additional advantages and modifications will readily occur to those skilled in the art. The disclosure in its broader terms is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described.