JP2013229461A - Servo amplifier including heat sink with fins having wall thickness and pitch dependent on distance from heat source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a servo amplifier including a heat sink which can be manufactured inexpensively, and can be used effectively even in an application where calorific value increases.SOLUTION: The heat sink for use in a servo amplifier is formed by arranging a plurality of heat dissipation elements, each having a base plate and a plurality of fins extending from the surface of the base plate. The fins of a heat dissipation element on the proximal side for the heat source are formed to have a wall thickness larger than that of the fins of a heat dissipation element on the distal side for the heat source. Furthermore, the fins of a heat dissipation element on the proximal side are formed at a pitch larger than that of the fins of a heat dissipation element on the distal side.

Description

  The present invention relates to a servo amplifier provided with a heat sink.

  High-power servo amplifiers tend to increase the amount of heat generated from power semiconductor devices that are responsible for controlling the supply of power applied to the servomotor, and large heat sinks are used accordingly. Further, in order to increase the heat radiation area of the heat sink within a limited volume range, it is widely performed to form long and thin fins at a narrow pitch. However, since such a long thin fin has a small cross-sectional area, the thermal resistance increases. Therefore, heat is not easily transmitted to the tip of the fin. Thereby, the heat dissipation action decreases as the tip of the fin is approached. As a result, the fin efficiency (= the effective surface area of the fin / the geometric surface area of the fin) is reduced, and the heat dissipation action is limited. Further, when the fin tong ratio (= fin height / fin gap) increases to a level exceeding 10, for example, it is difficult to manufacture a heat sink using extrusion molding which is a relatively inexpensive manufacturing method. is there.

JP 2001-85558 A Japanese Patent No. 2685918 Japanese Patent No. 3431004

  The present invention has been made in view of various problems of the prior art, and is also used in applications where the amount of heat generation is increased, such as a servo amplifier equipped with a power semiconductor device, while the manufacturing cost including the assembly cost is low. It is an object to provide a servo amplifier having a heat sink that can be used effectively.

  According to a first aspect of the present invention, there is provided a servo amplifier including a power semiconductor device and a heat sink for dissipating heat generated from the power semiconductor device, the heat sink comprising: a base plate; and the base A plurality of fins formed so as to extend from one surface of the plate, and the plurality of heat dissipation elements, the base plates of the heat dissipation elements extending in parallel to each other In addition, the plurality of fins are arranged so that the extending directions thereof face the same direction, and one of the base plates and the other base plate of the adjacent heat dissipating elements are connected to each other by the plurality of fins. The thickness of the fins of the proximal heat dissipating element disposed proximal to the heat source is disposed distal to the heat source. The pitch of the plurality of fins of the proximal side heat radiating element is larger than the thickness of the plurality of fins of the distal side heat radiating element, and the pitch of the plurality of fins of the distal side heat radiating element is larger. A servo amplifier is provided.

  According to a second aspect of the present invention, in the first aspect, the size of the gap between the plurality of fins in the proximal side heat radiating element is equal to or larger than the size of the gap between the plurality of fins in the distal side heat radiating element. A servo amplifier is provided.

  According to the third aspect of the present invention, there is provided a servo amplifier according to the first or second aspect, wherein the plurality of heat dissipating elements are separate parts.

  According to the first invention, the heat sink is formed by combining a plurality of heat dissipating elements. Therefore, the proximal heat dissipating element disposed proximally with respect to the heat source and the dissipating heat dissipating element disposed distally with respect to the heat source are arranged so that each has an optimum thickness and pitch. Can be formed independently. Specifically, the thickness of the fin of the proximal heat dissipating element is made larger than the thickness of the fin of the dissipating heat dissipating element. Further, the pitch of the fins of the proximal heat dissipation element is made larger than the pitch of the fins of the distal heat dissipation element. If it does in this way, the thermal radiation element which forms a heat sink will come to show optimal thermal radiation operation according to the distance from a heat source, respectively, and the thermal radiation performance improves as a whole.

  According to the second aspect of the invention, the fin gap in the proximal heat dissipation element is formed larger than the fin gap in the distal heat dissipation element. Therefore, air easily passes through the gaps between adjacent fins, so that the heat radiation effect by air cooling is improved.

  According to the third aspect, each heat dissipating element is formed as a separate part. Therefore, a heat sink can be provided by assembling heat dissipation elements having relatively simple structures. As a result, it is possible to provide a servo amplifier including a heat sink having high heat dissipation performance while keeping the manufacturing cost low.

1 is a schematic perspective view showing a servo amplifier according to an embodiment of the present invention. It is a schematic perspective view which shows the heat sink which concerns on one Embodiment of this invention. It is sectional drawing of the heat sink seen along line III-III of FIG. FIG. 4 is a partially enlarged view showing a region IV of FIG. 3 in an enlarged manner. It is a figure which shows the aspect at the time of using the heat sink of FIG. It is sectional drawing which shows the heat sink which concerns on another embodiment of this invention. It is the elements on larger scale which expand and show the area | region VII of FIG. It is an exploded view which shows the heat sink which concerns on another embodiment of this invention. It is sectional drawing which shows the heat sink which concerns on another embodiment of this invention. It is the elements on larger scale which expand and show the area | region X of FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that each component in the illustrated embodiment may have been scaled from a practical scale to aid in understanding the present invention.

  FIG. 1 is a schematic perspective view showing a servo amplifier 10 according to an embodiment of the present invention. The servo amplifier 10 includes a main body 12, a heat sink 14 attached close to a heat source (not shown) of the main body 12, and a fan 18 that forms a flow of air through a gap between fins forming the heat sink 14. ing. The servo amplifier 10 is a high-output servo amplifier that controls power supply to the servo motor by using, for example, a power semiconductor. The heat sink 14 is accommodated in a casing 16 indicated by a broken line in FIG. The base plate of the heat sink 14 is attached so as to contact the surface of the main body 12 of the servo amplifier 10 and is in thermal contact with the heat source of the main body 12.

Since each component of the servo amplifier 10 excluding the heat sink 14 is well known, detailed description thereof is omitted in this specification. The illustrated servo amplifier 10 is merely an example schematically shown. Therefore, the configuration of the servo amplifier 10, for example, the positional relationship between the main body 12 and the heat sink 14, and the volume ratio between the main body 12 and the heat sink 14 can be arbitrarily changed.

  Subsequently, a heat sink 20 according to an embodiment of the present invention will be described with reference to FIGS. 2 to 4. FIG. 2 is a schematic perspective view showing the heat sink 20. 3 is a cross-sectional view of the heat sink 20 as viewed along line III-III in FIG. FIG. 4 is a partially enlarged view showing a region IV surrounded by a broken line in FIG. 3 in an enlarged manner. As shown in FIGS. 2 and 3, the heat sink 20 includes a first heat radiating element 30 and a second heat radiating element 40 which are made of an arbitrary metal material having high heat conductivity and are integrally formed. .

  The first heat radiating element 30 includes a base plate 32 and a plurality of fins 34 formed at a predetermined pitch p1 so as to extend from one surface 32a of the base plate 32 substantially perpendicularly to the surface 32a. Have. The other surface 32b of the base plate 32 is in thermal contact with a heat source (not shown). The second heat radiating element 40 includes a base plate 42 and a plurality of fins 44 formed at a predetermined pitch p2 so as to extend substantially perpendicularly to the surface 42a from one surface 42a of the base plate 42. Have. 2 and 3, the extending direction of the fins 34 of the first heat radiating element 30 and the extending direction of the fins 44 of the second heat radiating element 40 are directed in the same direction. In the present embodiment, the first heat radiating element 30 is a proximal side heat radiating element disposed proximal to the heat source. Moreover, the 2nd thermal radiation element 40 is a distal side thermal radiation element arrange | positioned distally with respect to a heat source.

  The base plate 32 of the first heat dissipating element 30 and the base plate 42 of the second heat dissipating element 40 extend substantially parallel to each other. A plurality of fins 34 of the first heat dissipation element 30 extend between the base plate 32 of the first heat dissipation element 30 and the base plate 42 of the second heat dissipation element 40. Thus, the base plate 32 of the first heat dissipation element 30 and the base plate 42 of the second heat dissipation element 40 are connected to each other by the plurality of fins 34.

  FIG. 5 is a diagram showing an aspect when the heat sink 20 of FIG. 2 is used. The heat sink 20 is housed and used in a generally rectangular tube-shaped housing 16 having openings 16a and 16b formed on both end surfaces. A duct that acts as an air flow path is formed in the internal space of the housing 16 by the peripheral wall 16 c of the housing 16. A suction fan 18 is attached to one opening 16 a of the housing 16 so that air flows into the internal space of the housing 16. The arrows in FIG. 5 indicate the direction of air flow. The air flowing through the inner space of the housing 16 has an effect of taking heat away from the heat sink 20 by exchanging heat with the surface of the heat sink 20, mainly with the fins 34 and 44 of the heat dissipation elements 30 and 40.

  With reference to FIG. 4, the relationship between the dimension of the several fin 34 of the 1st thermal radiation element 30 and the dimension of the several fin 44 of the 2nd thermal radiation element 40 is demonstrated. Each fin 34 of the first heat dissipating element 30 has a thickness t1, and is formed at a pitch p1 so as to extend between the surface 32a of the base plate 32 and the surface 42b of the base plate 42. . On the other hand, each fin 44 of the second heat radiating element 40 has a thickness t2, and is formed at a pitch p2 so as to extend in a direction away from the first heat radiating element 30 on the surface 42a of the base plate 42. Has been.

  In the present embodiment, the thickness t1 of the fin 34 of the first heat dissipation element 30 is formed larger than the thickness t2 of the fin 44 of the second heat dissipation element 40 (that is, t1> t2). . Further, the pitch p1 of the fins 34 of the first heat dissipation element 30 is formed larger than the pitch p2 of the fins 44 of the second heat dissipation element 40 (that is, p1> p2).

  In the first heat dissipating element 30 disposed proximal to the heat source, the amount of heat passing through the fins 34 is large, so that the temperature gradient tends to increase. Accordingly, the fins 34 of the first heat radiating element 30 are formed to have a larger thickness than the fins 44 of the second heat radiating element 40. Thereby, the thermal resistance of the fins 34 of the first heat radiating element 30 is lowered. Accordingly, more heat is transferred through the first heat dissipating element 30. Then, heat is sufficiently transferred to the second heat radiating element 40 connected to the tip of the fin 34 of the first heat radiating element 30. On the other hand, when the wall thickness t1 of each fin 34 is simply increased in this way, the gap between adjacent fins 34 is reduced and the air flow is inhibited. Therefore, in the heat sink 20 according to the present embodiment, the pitch p1 of the fins 34 of the first heat dissipating element 30 is larger than the pitch p2 of the fins 44 of the second heat dissipating element 40. Thereby, even when the fins 34 have a relatively large thickness t1, a sufficiently large gap is formed between the fins 34. Therefore, the cooling effect by the air flowing through the gaps of the fins 34 can be maintained.

  On the other hand, since the amount of heat passing through the second heat radiating element 40 disposed distal to the heat source is relatively small, the thickness t2 of the fins 44 of the second heat radiating element 40 may be relatively small. Rather, since the thickness t2 of each fin 44 is small, more fins 44 can be formed on the base plate 42 having the same dimensions. Thereby, the heat radiation effect | action as the 2nd thermal radiation element 40 whole improves.

  As described above, according to the heat sink 20 according to the present embodiment, the fins 34 of the first heat radiating element 30 and the fins 44 of the second heat radiating element 40 are formed so as to have optimum shapes independently of each other. Is done. Therefore, fin efficiency improves and the heat dissipation performance as the heat sink 20 improves. In addition, in such a heat sink 20, since the stepwise heat radiation action by the first heat radiation element 30 and the second heat radiation element 40 is used, the height of the fin 34 of the first heat radiation element 30 and the second heat radiation element 30 are reduced. The shapes of the fins 34 and 44 may be determined so as to be approximately the same as the height of the fins 44 of the heat dissipation element 40.

  Subsequently, another embodiment of the present invention will be described. In the following description, matters overlapping with those already described in relation to the above-described embodiment are omitted as appropriate.

  FIG. 6 is a cross-sectional view showing a heat sink 22 according to another embodiment of the present invention. FIG. 7 is a partially enlarged view showing a region VII surrounded by a broken line in FIG. 6 in an enlarged manner. The heat sink 22 according to the present embodiment also includes the first heat radiating element 30 and the second heat radiating element 40 in the same manner as the heat sink 20 according to the above-described embodiment.

  In the heat sink 22 according to this embodiment, the size of the gap g1 between the adjacent fins 34, 34 of the first heat radiating element 30 is the same as that of the gap g2 between the adjacent fins 44, 44 of the second heat radiating element 40. It is formed so as to be larger than the dimension (that is, g1 ≧ g2). The gaps g1 and g2 between the fins 34 and 44 are obtained by subtracting the thicknesses t1 and t2 of the fins 34 and 44 from the pitches p1 and p2 of the fins 34 and 44. Between the thickness t1 of the fin 34 of the first heat dissipation element 30 and the thickness t2 of the fin 44 of the second heat dissipation element 40, as in the case of the heat sink 20 according to the above-described embodiment, t1> The relationship t2 is established. Further, between the pitch p1 of the fins 34 of the first heat radiating element 30 and the pitch p2 of the fins 44 of the second heat radiating element 40, as in the case of the heat sink 20 according to the above-described embodiment, p1> The relationship of p2 is established.

  According to such a configuration, the gap g1 between the fins 34 of the first heat dissipating element 30 has a dimension equal to or larger than the gap g2 between the fins 44 of the second heat dissipating element 40. Accordingly, the first heat dissipating element 30 that is disposed proximal to the heat source and is likely to be hot has the relatively thick fins 34, but the air flow between the fins 34 is The flow rate is equal to or greater than the flow of air passing between the fins 44 of the second heat dissipation element 40. Therefore, the temperature rise of the first heat dissipation element 30 can be suppressed.

  FIG. 8 is an exploded view showing a heat sink 24 according to still another embodiment of the present invention. In the heat sink 24 according to the present embodiment, the first heat radiating element 30 and the second heat radiating element 40 are separate parts, and the heat sink 24 is formed by joining the heat radiating elements 30 and 40 to each other. . Alternatively, the heat dissipating elements 30 and 40 may be coupled by other methods. For example, as illustrated, a fitting groove 46 formed on a surface 42 b of the base plate 42 of the second heat radiating element 40 facing the first heat radiating element 40 may be used. In this case, the first heat radiating element 30 and the second heat radiating element 40 are relatively positioned by fitting the tips of the fins 34 of the first heat radiating element 30 into the fitting grooves 46. From this state, the heat dissipating elements 30 and 40 can be coupled to each other using brazing, soldering, bonding or other known means. Further, by fitting the fins 34 into the fitting grooves 46, the coupling area between the fins 34 of the first heat radiating element 30 and the base plate 42 of the second heat radiating element 40 is increased. There is an advantage that the mechanical strength of the bonding state between them increases and the contact thermal resistance between these parts decreases.

  According to this embodiment, each thermal radiation element 30 and 40 can be manufactured separately. And since the tongue rate of each thermal radiation element 30 and 40 is comparatively small, the thermal radiation elements 30 and 40 can be formed by cheap methods, such as extrusion molding, for example. Since it is difficult to form a part having a large tongue ratio by extrusion molding, conventionally, it has been common to form a heat sink by fixing fins to a base plate by brazing or caulking. The heat sink 24 according to the present embodiment is particularly advantageous as compared with such a conventional type heat sink. Since there is a correlation between the tongue rate and ease of manufacture, the shape of the fins 34 and 44 may be determined so that the tongue rates of the fins 34 and 44 of the heat dissipating elements 30 and 40 are approximately the same. .

  In the present embodiment, the first heat radiating element 30 and the second heat radiating element 40 may be formed of different materials. For example, it is conceivable to form the first heat dissipating element 30 from copper or a copper alloy having good thermal conductivity and to form the second heat dissipating element 40 from a lightweight aluminum alloy. In this way, an optimal combination of materials is selected in consideration of various factors such as heat transfer, price and weight.

  FIG. 9 is a cross-sectional view showing a heat sink 26 according to still another embodiment of the present invention. FIG. 10 is a partially enlarged view showing a region X surrounded by a broken line in FIG. 9 in an enlarged manner. The heat sink 26 according to this embodiment is obtained by further adding a third heat dissipation element 50 to the heat sink 20 according to the above-described embodiment. That is, the heat sink 26 includes a first heat radiating element 30, a second heat radiating element 40, and a third heat radiating element 50. The third heat radiating element 50 having substantially the same form as that of the second heat radiating element 40 includes a base plate 52 and a surface 52a of the base plate 52 in a direction away from the second heat radiating element 40 with respect to the surface 52a. And a plurality of fins 54 formed at a predetermined pitch p3 so as to extend substantially vertically.

  The thickness t3 of the fins 54 of the third heat dissipation element 50 is formed smaller than the thickness t2 of the fins 44 of the second heat dissipation element 40 (that is, t3 <t2). Further, the pitch p3 of the fins 54 of the third heat dissipation element 50 is formed smaller than the pitch p2 of the fins 44 of the second heat dissipation element 40 (that is, p3 <p2).

  Between the thickness t1 of the fin 34 of the first heat dissipation element 30 and the thickness t2 of the fin 44 of the second heat dissipation element 40, as in the case of the heat sink 20 according to the above-described embodiment, t1> The relationship t2 is established. Therefore, a relationship of t1> t2> t3 is established between the thicknesses t1, t2, and t3 of the fins 34, 44, and 54 of the heat dissipating elements 30, 40, and 50. Further, between the pitch p1 of the fins 34 of the first heat radiating element 30 and the pitch p2 of the fins 44 of the second heat radiating element 40, as in the case of the heat sink 20 according to the above-described embodiment, p1> The relationship of p2 is established. Therefore, a relationship of p1> p2> p3 is established between the pitches p1, p2, and p3 of the fins 34, 44, and 54 of the heat dissipating elements 30, 40, and 50.

  As described above, according to the present embodiment, in the heat sink 26 including the three heat radiating elements, the thickness of the fin becomes thicker as the heat radiating element disposed on the proximal side with respect to the heat source. As a result, the thermal resistance of the fin on the proximal side is lowered, so that heat can be more efficiently transferred to the fin on the distal side. Therefore, it can prevent that the temperature of the fin of a distal side falls too much and a heat dissipation effect is impaired. Since the heat sink 26 according to the present embodiment is further subdivided than the heat sinks 22 and 24 composed of the two heat dissipating elements described above, it is possible to optimally design a finer fin shape.

  Further, the pitch of the fins becomes larger as that of the heat dissipating element disposed on the proximal side with respect to the heat source. As a result, a sufficiently large cooling air flow path is formed while the fins are relatively thick. As a result, the flow rate of air passing through the proximal heat dissipating element is increased, and the proximal heat dissipating element that is likely to increase in temperature can be cooled more effectively.

  Although a plurality of embodiments according to the present invention have been described above, it should be understood that the present invention is not limited to the specific embodiments illustrated. The present invention can be implemented by arbitrarily combining the matters individually described in relation to each embodiment unless they are technically contradictory. Further, although the heat sink according to the illustrated embodiment is formed by combining two or three heat dissipation elements, the heat sink may be formed by combining four or more heat dissipation elements. Thus, in a heat sink in which a large number of heat dissipating elements are combined, an optimum fin shape for each heat dissipating element can be adopted by subdividing according to the distance from the heat source. Therefore, fin efficiency can be further improved.

  Further, a plurality of heat sinks according to the present invention as described above may be arranged as a cooling means of the servo amplifier by arranging them at a predetermined distance apart in the air flow direction. In this case, in the gap between the heat sinks, hot air flowing out from the heat dissipating element proximal to the heat source (for example, the first heat dissipating element 30) and the heat dissipating element distal to the heat source (for example, Heat exchange is performed with the low-temperature air flowing out from the second heat dissipating element 40). As a result, it is possible to prevent the temperature of the air from locally increasing, and to suppress a decrease in the cooling effect accompanying the increase in the temperature of the air.

DESCRIPTION OF SYMBOLS 10 Servo amplifier 14 Heat sink 20 Heat sink 22 Heat sink 24 Heat sink 26 Heat sink 30 1st thermal radiation element 32 Base board 34 Fin 40 2nd thermal radiation element 42 Base board 44 Fin 50 3rd thermal radiation element 52 Base board 54 Fin t1 Thickness t2 Thickness t3 Thickness p1 Pitch p2 Pitch p3 Pitch g1 Gap g2 Gap

Claims (3)

A servo amplifier comprising a power semiconductor device and a heat sink for dissipating heat generated from the power semiconductor device,
The heat sink includes a plurality of heat dissipating elements having a base plate and a plurality of fins formed so as to extend from one surface of the base plate. The base plates extend in parallel with each other and the extending directions of the plurality of fins are aligned in the same direction, and one of the base plates and the other base plate of the adjacent heat dissipating elements are arranged. And a heat sink formed to be connected to each other by the plurality of fins,
The thickness of the fins of the proximal heat dissipating element disposed proximal to the heat source is greater than the wall thickness of the fins of the distal heat dissipating element disposed distal to the heat source. And a pitch of the plurality of fins of the proximal side heat dissipation element is larger than a pitch of the plurality of fins of the distal side heat dissipation element.   2. The servo amplifier according to claim 1, wherein a size of the gap between the plurality of fins in the proximal side heat radiating element is equal to or larger than a size of the gap between the plurality of fins in the distal side heat radiating element.   The servo amplifier according to claim 1, wherein the plurality of heat dissipating elements are separate parts.

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