Method of producing heat-dissipating unit

Abstract

[Purpose] To provide is a method capable of producing a heat-dissipating unit easily and at low cost. [Solution] The method of producing a heat-dissipating unit 12 includes: inserting pins 17 punched out of a second plate member 22 for pins into a plurality of through-holes 16 formed in a first plate member 20 for a substrate. In the first plate member 20, a plurality of substrate forming portions 25 is provided side by side in the longitudinal direction of the first plate member 20. In the second plate member 22, a plurality of pin punch-out portions 26 is provided side by side in the longitudinal direction of the second plate member 22. The method includes: a step A of forming the through-holes 16 in the substrate forming portion 25 of the first plate member 20; a step B of subjecting the pin punch-out portion 26 of the second plate member 22 to a half-punch out process to form half-punched-out pin forming portions 27 protruding from one surface side of the second plate member 22; a step C of forming the pins 17 by punching out the pin forming portions 27 from the second plate member 22 and simultaneously inserting the pins 17 into the through-holes 16 in the first plate member 20; and a step D of forming a substrate by cutting the substrate forming portion 25 with the pins 17 inserted in the through-holes 16 from the first plate member 20.

Claims

1. A method of producing a heat-dissipating unit, wherein the heat-dissipating unit comprises a substrate having a plurality of through-holes formed therein and a plurality of pins fixed to the substrate in a state in which the pins are inserted in the through-holes of the substrate with both longitudinal end portions of the pins protruded from the through-hole by a certain length, and portions of the pins protruding from the through-holes serve as fins, the method comprising: punching the plurality of pins out of a second plate member to produce the plurality of pins and inserting the plurality of pins into the plurality of through-holes formed in a first plate member for the substrate, wherein the punching and inserting steps are performed simultaneously.

2. The method of producing a heat-dissipating unit as recited in claim 1, further comprising: forming a certain number of the through-holes required for a single substrate in a substrate forming portion located at one end portion of the first plate member in which a plurality of substrate forming portions each having a size for forming one substrate is provided side by side in a longitudinal direction of the first plate member; thereafter inserting the pins into the through-holes of the substrate forming portion; and subsequently cutting the substrate forming portion in which the pins are inserted into the through-holes from the first plate member to produce a substrate.

3. The method of producing a heat-dissipating unit as recited in claim 2, further comprising: forming a plurality of half-punched-out pin forming portions protruding on one surface side of the second plate member in a pin punch-out portion located at one end portion of the second plate member in which the plurality of pin punch-out portions, each from which a certain number of pins required for one substrate are punched out, are provided side by side in a longitudinal direction of the second plate member, wherein the simultaneous punching and inserting includes punching the plurality of half-punched-out pin forming portions of the pin punch-out portion from the second plate member to produce the plurality of pins and inserting the plurality of pins into the through-holes of the substrate forming portion located at the one end portion of the first plate member.

4. The method of producing a heat-dissipating unit as recited in claim 3, further comprising: performing a step A of forming the through-holes in the substrate forming portion of the first plate member; a step B of subjecting the pin punch-out portion of the second plate member to a half-punch-out process to form a half-punched-out pin forming portion protruding on one surface side of the second plate member; a step C of punching the pin forming portion from the second plate member to form the pins and simultaneously inserting the pins into the through-holes of the substrate forming portion of the one end portion of the first plate member; and a step D of cutting the substrate forming portion in which the pins are inserted into the through-holes from the first plate member to produce the substrate by a single die.

5. The method of producing a heat-dissipating unit as recited in claim 4, further comprising: performing a step E of cutting the pin punch-out portion from the second plate member after forming the plurality of pins from the pin punch-out portion located at one end portion of the second plate member, wherein the step E is performed by the die for performing the steps A to D.

6. The method of producing a heat-dissipating unit as recited in claim 5, further comprising: arranging a first coil in which the first plate member is wound and a second coil in which the second plate member is wound so that feeding directions of both the plate members from both the coils are orthogonal as seen from a plane; and performing the steps A to E while intermittently feeding the first plate member from the first coil and intermittently feeding the second plate member from the second coil.

7. The method of producing a heat-dissipating unit as recited in claim 1, further comprising: preparing a substrate having a required number of through-holes using the first plate member.

8. The method of producing a heat-dissipating unit as recited in claim 1, wherein the second plate member is made of JIS A1000 series aluminum.

9. The method of producing a heat-dissipating unit as recited in claim 1, wherein the second plate member is made of JIS A6000 series aluminum.

10. The method of producing a heat-dissipating unit as recited in claim 1, wherein when the pins are inserted into the through-holes of the first plate member, the pins are press-fitted therein.

11. The method of producing a heat-dissipating unit as recited in claim 1, wherein a brazing material layer is provided on at least one surface of the first plate member.

12. The method of producing a heat-dissipating unit as recited in claim 1, wherein a brazing material layer is provided on at least one surface of the second plate member.

13. The method of producing a heat-dissipating unit as recited in claim 1, wherein a cross-sectional shape of each of the pins to be punched is circular, and a ratio L/D of a length L of each of the pins to a diameter D is 1.7 or less.

14. The method of producing a heat-dissipating unit as recited in claim 1, wherein a shape of the through-hole of the first plate member is a streamline shape, and a cross-sectional shape of each of the pins is a streamline shape having an arc edge and a pointed edge oriented in a same direction as an arc edge and a pointed edge of the through-hole, respectively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view showing the overall configuration of a cooling apparatus provided with a heat radiator composed of a heat-dissipating unit produced by the method of the present invention.

(2) FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1.

(3) FIG. 3 is a partially enlarged view of FIG. 2.

(4) FIG. 4 is a perspective view showing the overall configuration of the heat radiator for use in the cooling apparatus shown in FIG. 1

(5) FIG. 5 is a plan view schematically showing a method of producing a heat-dissipating unit according to the present invention.

(6) FIG. 6 is a view taken along the line B-B in FIG. 5.

(7) FIGS. 7A, 7B, and 7C are views showing methods of producing a heat-dissipating unit according to the present invention in the order of steps, wherein FIG. 7A corresponds to an enlarged cross-sectional view taken along the line C-C in FIG. 5, FIG. 7B corresponds to the enlarged cross-sectional view taken along the line D-D in FIG. 5, and FIG. 7C corresponds to the enlarged cross-sectional view taken along the line E-E in FIG. 5.

(8) FIG. 8 is a perspective view schematically showing a method of producing a heat-dissipating unit according to the present invention.

(9) FIG. 9 is a view corresponding to FIG. 7C showing a first modified embodiment of the heat-dissipating unit to be produced by the method of the present invention.

(10) FIG. 10 is a view corresponding to FIG. 7C showing a second modified embodiment of the heat-dissipating unit to be produced by the method of the present invention.

(11) FIG. 11 is a view corresponding to FIG. 7C showing a third modified embodiment of the heat-dissipating unit to be produced by the method of the present invention.

(12) FIG. 12 is a plan view showing a fourth modified embodiment of the heat-dissipating unit to be produced by the method of the present invention.

DESCRIPTION OF REFERENCE SYMBOLS

(13) 12, 30, 35, 40, 45: heat-dissipating unit 14: substrate 15: fin 16: through-hole 17: pin 20: first plate member 21: first coil 22: second plate member 23: second coil 24: die 25: substrate forming portion 26: pin punch-out portion 27: pin forming portion 31, 36: brazing material layer of the substrate 41: brazing material layer of the pin 46: through-hole 47: pin

EMBODIMENT FOR CARRYING OUT THE INVENTION

(14) Hereinafter, some embodiments of the present invention will be described with reference to the drawings. This embodiment is directed to a heat-dissipating unit used in a liquid-cooling type cooling apparatus by the method of the present invention.

(15) Note that in this specification, the term “aluminum” is used to include the meaning of an aluminum alloy in addition to pure aluminum.

(16) Note that in the following description on the cooling apparatus, the upper, lower, left, and right sides in FIG. 2 will be referred to as the upper, lower, left, and right side, respectively.

(17) Further note that the same symbols are allotted to the same items and the same portions throughout the drawings.

(18) FIG. 1 and FIG. 2 show an overall structure of a cooling apparatus having a heat-dissipating unit produced by the method of the present invention, and FIG. 3 shows the structure of the main part thereof. FIG. 4 shows a heat radiator used in the cooling apparatus of FIG. 1. Further, FIG. 5 to FIG. 8 show a method of producing a heat-dissipating unit according to the present invention.

(19) In FIG. 1 and FIG. 2, the liquid-cooling type cooling apparatus 1 is provided with a hollow casing 2 having a top wall 2a, a bottom wall 2b, and a peripheral wall 2c and provided with a cooling fluid passage 3 therein, and a heat radiator 4 arranged in the cooling fluid passage 3 in the casing 2.

(20) At one longitudinal end portion in the casing 2 (at the right end portion in this embodiment), an inlet header 5 into which a cooling fluid flows from the outside is provided, while at the other longitudinal end portion in the casing 2 (at the left end portion in this embodiment), an outlet header 6 from which the cooling fluid flows to the outside is provided. Thus, the cooling fluid passage 3 is configured to flow the cooling fluid flowed into the inlet header 5 to the outlet header 6. To the top wall 2a of the casing 2, an aluminum inlet pipe 7 for supplying a cooling fluid to the inlet header 5 in the casing 2 and an aluminum outlet pipe 8 for discharging the cooling fluid from the outlet header 6 in the casing 2 are connected. Further, it is configured such that on at least one of the outer surface of the top wall 2a and the outer surface of the bottom wall 2b of the casing 2 (the outer surface of the top wall 2a in this embodiment), a heating element (not shown), such as, e.g., a power device such as an IGBT, an IGBT modules integrated with a control circuit and housed in the same package, an intelligent power module in which a protection circuit is further integrated with the IGBT module and housed in the same package, is attached.

(21) The casing 2 is composed of a plate-shaped aluminum upper constituent element 9 forming the top wall 2a and an upwardly opened box-like aluminum lower constituent element 11 forming a bottom wall 2b and a peripheral wall 2c. The lower surface peripheral edge portion of the upper constituent element 9 is joined with a brazing material (hereinafter referred to as “brazed”) to the upper end portion of the portion forming the peripheral wall 2c of the lower constituent element 11.

(22) As shown in FIG. 2 to FIG. 4, the heat radiator 4 is provided with a plurality of heat-dissipating units 12 (two heat-dissipating units 12 in this embodiment), arranged in a stacked manner in the vertical direction and an aluminum intermediate plate 13 arranged between adjacent heat-dissipating units 12. The heat-dissipating unit 12 is composed of a horizontal aluminum substrate 14 and a plurality of aluminum fins 15 provided on both surfaces of the substrate 14 so as to protrude from the substrate 14 with its longitudinal direction oriented in the vertical direction. A plurality of circular through-holes 16 is formed in the substrate 14, and an aluminum round bar-shaped pins 17 are inserted in the circular through-holes 16 and secured to the substrate 14 with the longitudinal central portion positioned in the circular through-hole 16. The portions of the pin 17 protruding upward and downward from the circular through-hole 16 serve as both the upper and lower fins 15. The substrate 14 is made of, for example, JIS A3000 series aluminum, JIS A1000 series aluminum, or JIS A6000 series aluminum, and the pin 17 is made of, for example, JIS A1000 series aluminum or JIS A6000 series aluminum. Securing of the pin 17 to the substrate 14 is performed by press-fitting into the circular through-hole 16 or brazing.

(23) The tip of the upper fin 15 of the upper heat-dissipating unit 12 is in thermal contact with the inner surface of the top wall 2a of the casing 2. In the same manner, the tip of the lower fin 15 is in thermal contact with the upper surface of the intermediate plate 13. Further, the tip of the lower fin 15 of the lower heat-dissipating unit 12 is in thermal contact with the inner surface of the bottom wall 2b of the casing 2. In the same manner, the tip of the upper fin 15 is in thermal contact with the lower surface of the intermediate plate 13. In this way, the substrates 14 of both the heat-dissipating units 12 and the intermediate plate 13 are vertically spaced apart. The cross-sectional shapes of both the upper and lower fins 15 of both the heat-dissipating units 12 arranged adjacently in the vertical direction are each a circular shape of the equal size, and all of the upper and lower fins 15 of both the heat-dissipating units 12 arranged adjacently in the vertical direction are overlapped at least partly (entirely in this embodiment) as viewed from a plane.

(24) The cooling apparatus 1 is produced by the method including: arranging two heat-dissipating units 12 in the lower constituent element 11 in a state of being stacked via the intermediate plate 13; placing the upper constituent element 9 thereon; and brazing both the upper and lower constituent elements 9 and 11. In the production method, in cases where the tip of the upper fin 15 of the upper heat-dissipating unit 12 is brazed to the inner surface of the top wall 2a of the casing 2 and the tip of the lower fin 15 is brazed to the upper surface of the intermediate plate 13, or in cases where the tip of the lower fin 15 of the lower heat-dissipating unit 12 is brazed to the inner surface of the bottom wall 2b of the casing 2 and the tip of the upper fin 15 is brazed to the lower surface of the intermediate plate 13, a separately prepared sheet-like brazing material is used.

(25) In the cooling apparatus 1 described above, the cooling fluid flowed into the inlet header 5 of the casing 2 through the inlet pipe 7 enters the cooling fluid passage 3, flows between the fins 15 in between the substrates 14 of both the upper and lower heat-dissipating units 12 and the top wall 2a and the bottom wall 2b of the casing 2 and in between the substrate 14 of each heat-dissipating unit 12 and the intermediate plate 13, enters the outlet header 6, and then is discharged from the outlet header 6 through the outlet pipe 8. The heat emitted from the heating element attached to the outer surface of the top wall 2a of the casing 2 is transmitted to the top wall 2a, and then transmitted to the substrates 14 and both the upper and lower fins 15 of both the heat-dissipating units 12, and then transmitted from the intermediate plate 13 to the cooling fluid flowing in the cooling fluid passage 3. Thus, the heating element is cooled.

(26) The heat transfer path of the heat emitted from the heating element and transferred to the top wall 2a of the casing 2 to the cooling fluid flowing in the cooling fluid passage 3 is as follows. The first path that transmits the heat emitted from the heating element attached to the outer surface of the top wall 2a of the casing 2 to the cooling fluid is a path through which the heat is transmitted directly from the top wall 2a to the cooling fluid. The second path is a path through which the heat is transmitted from the top wall 2a to both the upper and lower fins 15 of the upper heat-dissipating unit 12 and then transmitted from both the upper and lower fins 15 to the cooling fluid. The third path is a path through which the heat is transmitted from the top wall 2a to the substrate 14 via the upper fin 15 of the upper heat-dissipating unit 12 and then transmitted from the substrate 14 to the cooling fluid. The fourth path is a path through which the heat is transmitted from the top wall 2a to the intermediate plate 13 via both the upper and lower fins 15 of the upper heat-dissipating unit 12 and then transmitted from the intermediate plate 13 to the cooling fluid. The fifth path is a path through which the heat is transmitted from the top wall 2a to the upper and lower fins 15 of the lower heat-dissipating unit 12 via both the upper and lower fins 15 of the upper heat-dissipating unit 12 and the intermediate plate 13 and then transmitted from both the upper and lower fins 15 to the cooling fluid. The sixth path is a path through which the heat is transmitted from the top wall 2a to the upper fin 15 of the lower heat-dissipating unit 12 via both the upper and lower fins 15 of the upper heat-dissipating unit 12 and the intermediate plate 13 and further transmitted to the substrate 14 via the upper fin 15 and from the substrate 14 to the cooling fluid.

(27) In the cooling apparatus 1 described above, the heat radiator 4 is composed of two heat-dissipating units 12, but the heat radiator may be composed of three or more heat-dissipating units 12 and an intermediate plate 13 arranged between adjacent heat-dissipating units 12.

(28) Next, with reference to FIG. 5 to FIG. 8, a method of producing the heat-dissipating unit 12 used in the heat radiator 4 of the cooling apparatus 1 of FIG. 1 will be described. The method shown in FIG. 5 to FIG. 8 is directed to a method of producing a heat-dissipating unit of a type in which the pins 17 are press-fitted into the through-holes 16 of the substrate 14.

(29) In the following description, the left and right sides of FIG. 5 will be referred to as left and right sides, respectively, and the lower side of FIG. 5 will be referred to as a front side.

(30) As shown in FIG. 5 to FIG. 8, for example, a first coil 21 in which the first plate member 20 for the substrate 14 made of JIS A3000 series aluminum is wound, a second coil 23 in which the second plate member 22 for the pin 17 made of JIS A1000 series aluminum or JIS A6000 series aluminum is wound, and a die 24 for performing various processing on the first plate member 20 fed from the first coil 21 and the second plate member 22 fed from the second coil 23 are prepared. The second coil 23 is arranged on the left front side of the first coil 21, and the die 24 is arranged on the front side of the first coil 21 and on the right side of the second coil 23.

(31) In the first plate member 20 wound on the first coil 21, a plurality of substrate forming portions 25 each having a size for forming one substrate 14 is provided side by side in the longitudinal direction of the first plate member 20. In the second plate member 22 wound on the second coil 23, a plurality of pin punch-out portions 26 each having the same size as the substrate forming portion 25 of the first plate member 20 for punching a required number of pins 17 for one substrate 14 is provided side by side in the longitudinal direction of the second plate member 22.

(32) The first coil 21 is configured to intermittently feed the first plate member 20 toward the die 24 by the length of one substrate forming portion 25. The second coil 23 is configured to feed the second plate member 22 to the right side toward the die 24 by the length of one pin punch-out portion 26. It is configured such that the first plate member 20 fed from the first coil 21 comes to the underside of the second plate member 22 fed out from the second coil 23, and the feeding directions of both the plate members 20 and 22 are orthogonal as viewed from a plane.

(33) The die 24 is provided with a punching portion for forming the through-holes 16 by punching the substrate forming portion 25 of the first plate member 20, a half-punching portion for forming a plurality of pin forming portions 27 (see FIG. 7A) protruding toward the lower surface side of the second plate member 22 by subjecting the pin punch-out portion 26 of the second plate member 22 to half-punching processing, a pin inserting portion for forming pins 17 by punching the pin forming portion 27 from the second plate member 22 and simultaneously inserting the pins 17 into the through-holes 16 of the substrate forming portion 25 of the one end portion of the first plate member 20, a cutting portion for cutting the substrate forming portion 25 having the pins 17 inserted into the through-holes 16 from the first plate member 20 to form the substrate 14, and a scrapping portion for cutting the pin punch-out portion 26 after forming the plurality of pins 17 from the pin punch-out portion 26 located at one end of the second plate member 22 from the second plate member 22.

(34) In producing the heat-dissipating unit 12, the substrate forming portion 25 of the tip portion is moved to the punching portion of the die 24 while intermittently feeding the first plate member 20 forward from the first coil 21 by the length of one substrate forming portion 25, and at the punching portion, the number of through-holes 16 required for one substrate 14 are simultaneously formed in the substrate forming portion 25 of the tip portion of the first plate member 20 (see Step A, and FIG. 8). Simultaneously with this, the second plate member 22 is moved to the half-punching portion of the die 24 while intermittently feeding the second plate member 22 rightward by the length of one pin punch-out portion 26 from the second coil 23, and at the half-punched portion, the pin punch-out portion 26 is subjected to half-punching to form a plurality of half-punched-out pin forming portions 27 protruding to the lower surface side of the second plate member 22 (see Step B, FIG. 7A and FIG. 8).

(35) Next, the substrate forming portion 25 of the first plate member 20 in which the through-holes 16 are formed is moved to the pin inserting portion of the die 24, and the pin punch-out portion 26 of the second plate member 22 in which the pin forming portion 27 is formed is moved to the pin-inserting portion of the die 24. At this time, the positions of all of the pin forming portions 27 coincide with the positions of all of the through-holes 16.

(36) Next, in the pin inserting portion of the die 24, simultaneously with punching the pin forming portion 27 from the second plate member 22 to form a plurality of pins 17, the pins 17 are press-fitted in the through-holes 16 of the substrate forming portion 25 of the one end portion of the first plate member 20 (see Step C, FIG. 7B, and FIG. 8). Here, it is preferable that the cross-sectional shape of the pin 17 be circular and the ratio L/D of the length L of the pin 17 to the diameter D thereof be 1.7 or less. In this case, the pin 17 can be punched out with high precision, and a number of pins 17 can be fixed to one substrate 14.

(37) Next, the substrate forming portion 25 in which the pins 17 is press-fitted in the through-holes 16 of the first plate member 20 is moved to the cutting portion of the die 24. At the cutting position, the substrate forming portion 25 in which the pins 17 are inserted in the through-holes 16 is cut from the first plate member 20 to form the substrate 14 (see Step D). Thus, the portion of the pin 17 protruding from the through-hole 16 is served as a fin 15. Thus, the heat-dissipating unit 12 is produced (see FIG. 7C and FIG. 8). On the other hand, the pin punch-out portion 26 of the second plate member 22 from which the pins 17 are punched out is moved to the scrapping portion of the die 24, and in the scrapping portion, the pin punch-out portion 26 is cut from the second plate member 22 into a scrap (Step E).

(38) The above-described Steps A to E in the die 24 are simultaneously performed for different substrate forming portions 25 and pin punch-out portions 26.

(39) In the above-described embodiment, the first plate member 20 fed out from the first coil 21 comes to the lower side of the second plate member 22 fed out from the second coil 23, but not limited to this. Depending on the type of the die 24, the first plate member 20 fed from the first coil 21 may be arranged above the second plate member 22 fed from the second coil 23.

(40) FIG. 9 to FIG. 12 show modified embodiments of the heat-dissipating unit to be produced by the method of the present invention.

(41) In the case of the heat-dissipating unit 30 shown in FIG. 9, one surface (upper surface) of the substrate 14 is covered with an aluminum brazing material layer 31, and the substrate 14 is made using a first plate member 20 formed of an aluminum brazing sheet with one surface covered with an aluminum brazing material layer.

(42) In the case of the heat-dissipating unit 35 shown in FIG. 10, both surfaces of the substrate 14 are each covered with an aluminum brazing material layer 36, and the substrate 14 is made using a first plate member 20 formed of an aluminum brazing sheet with both surfaces each covered with an aluminum brazing material layer.

(43) In the case of the heat-dissipating units 30 and 35 shown in FIG. 9 and FIG. 10, simultaneously with brazing the upper and lower constituent elements 9 and 11 of the casing 2 at the time of producing the above-described cooling apparatus 1, the substrate 14 and the pins 17 are brazed.

(44) In the case of the heat-dissipating unit 40 shown in FIG. 11, both the upper and lower end surfaces of the pin 17 are each covered with an aluminum brazing material layer 41, and the pin 17 is made using a second plate member 22 formed of an aluminum brazing sheet with both surfaces each covered with an aluminum brazing material layer.

(45) In the case of the heat-dissipating unit 40 shown in FIG. 11, simultaneously with the brazing of both the upper and lower constituent elements 9 and 11 of the casing 2 at the time of producing the cooling apparatus 1, the upper end surface of the upper fin 15 of the upper heat-dissipating unit 40 is brazed to the top wall 2a of the casing 2 and the lower end surface of the lower fin 15 is brazed to the intermediate plate 13, and the lower end surface of the lower fin 15 of the lower heat-dissipating unit 40 is brazed to the bottom wall 2b of the casing 2 and the upper end surface of the upper fin 15 is brazed to the intermediate plate 13.

(46) In the case of the heat-dissipating unit 45 shown in FIG. 12, the shape of the through-hole 46 of the substrate 14 is a streamline shape in which the arc edges and the pointed edges of the through-holes 46 are oriented in the same direction. The cross-sectional shape of the pin is a streamline shape in which the arc edges and the pointed edges of the pins are directed in the same direction as the arc edges and the pointed edges of the through-holes, respectively. The shape of the pin 47 which will be served as the upper and lower fins 15 as seen from a plane is a streamline shape in which the arc edges and the pointed edges of the pins are oriented in the same direction as the arc edges and the pointed edges of the through-holes 46, respectively.

(47) However, the shape of the through-hole 46 of the substrate 14 does not necessarily have an arc edge and a pointed edge facing in the same direction, respectively.

INDUSTRIAL APPLICABILITY

(48) The method according to the present invention is suitably used for producing a heat-dissipating unit of a cooling apparatus for cooling a power device, such as, e.g., an IGBT, in a power module, such as, e.g., a power conversion device to be mounted on an electric vehicle, a hybrid vehicle, or a train.