Liquid-cooled resistor

Abstract

To provide a liquid-cooled resistor capable of improving a cooling performance of a resistance unit, thereby preventing an abnormally high temperature of the resistance unit.SOLUTION: In a liquid-cooled resistor (1), a resistance unit (2) is stored in a storage space (18) of a cooling container (4) and cooled by a liquid. The cooling container (4) comprises an inlet-side partition wall (14) forming an inlet port (20) in a lower part and an outlet-side partition wall (16) forming an outlet port (22) in an upper part. The resistance unit (2) comprises resistive elements (30), a resistive body (32) configured by disposing a plurality of steps of resistive elements (30) in a longitudinal direction (Y) while electrically connecting them, and a plurality of insulators (34) supporting the resistive elements (30). A flow passage resistance member (50) for disturbing a flow of the liquid is provided at a position which is between a resistive element (30A) positioned in a highest step in the longitudinal direction (Y) and a resistive element (30B) positioned in a step under the highest step in the longitudinal direction (Y) and opposed with the outlet-side partition wall (16).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a liquid-cooled resistor, and more particularly to a liquid-cooled resistor in which a resistor unit having a resistance element that generates heat when energized is accommodated in an accommodating space of a cooling container and cooled by liquid. [Background technology]

[0002] Cooling systems that use liquid to cool electrical components having resistance elements such as coils that generate heat when current is applied are widely known. For example, Patent Document 1 discloses an oil-cooled, oil-filled transformer that cools the transformer body. In Patent Document 1, the transformer body, which is a heat-generating body, is housed in a tank, and liquid (insulating oil) that serves as a cooling medium circulates by flowing through a lower oil pipe equipped with a pump, the tank, an upper oil pipe, and a radiator, in that order.

[0003] Taking into account the thermal convection of the liquid heated by the cooling of the transformer body, the liquid is supplied from the lower oil pipe connected to the bottom of the tank and discharged from the upper oil pipe connected to the top of the tank. The liquid discharged from the upper oil pipe is cooled in a radiator and then supplied back to the tank from the lower oil pipe by a pump. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 54-123884 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, both the lower oil pipe and the upper oil pipe are connected to one side wall of the tank. Therefore, a large amount of liquid flows into a portion of the tank near the lower oil pipe and the upper oil pipe where the flow resistance is low, specifically, into the flow path formed between one side wall of the tank and the transformer body. This prevents the entire transformer body from being sufficiently cooled by the liquid, which may result in an abnormally high temperature in a portion of the transformer body. Therefore, there is a need for a liquid-cooled resistor that can improve the cooling performance of the transformer body, or in other words, the resistor unit, and prevent the resistor unit from becoming abnormally high temperature.

[0006] The present invention has been made in consideration of such problems, and aims to provide a liquid-cooled resistor that improves the cooling performance of the resistance unit and thereby prevents the resistance unit from becoming abnormally hot. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the liquid-cooled resistor of the present invention is a liquid-cooled resistor in which a resistance unit is accommodated in an accommodation space of a cooling container and cooled with liquid, the cooling container comprising an inlet-side partition that forms an inlet port at the bottom of the accommodation space in the vertical direction for allowing liquid to flow into the accommodation space, and an outlet-side partition that forms an outlet port at the top of the accommodation space in the vertical direction for allowing liquid to flow out of the accommodation space, the resistance unit comprising a resistance element that generates heat when current is applied, a resistor formed by arranging the resistance elements in multiple rows in the vertical direction while electrically connecting them, and a plurality of insulators arranged alternately with the resistance elements in the vertical direction and supporting each of the resistance elements, and characterized in that a flow path resistance member that obstructs the flow of liquid is provided between the resistance element located in the top row in the vertical direction and the resistance element located in the row below the top row in the vertical direction and in a position facing the outlet-side partition. [Effects of the Invention]

[0008] According to the present invention, the cooling performance of the resistance unit can be improved, and therefore the resistance unit can be prevented from becoming abnormally high in temperature. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating the configuration of a cooling system incorporating a liquid-cooled resistor according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic side view of a liquid-cooled resistor. [Figure 3] FIG. 2 is a schematic diagram of a liquid-cooled resistor viewed from above. [Figure 4] FIG. 2 is a perspective view showing the main part of the liquid-cooled resistor. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 10 is a perspective view of a flow path resistance member according to a modified example. [Figure 8] FIG. 4 is a side view illustrating the flow of liquid in the liquid-cooled resistor of the present embodiment. [Figure 9] FIG. 4 is a side view illustrating the flow of liquid in the liquid-cooled resistor of the first comparative example. [Figure 10] FIG. 10 is a side view illustrating the flow of liquid in the liquid-cooled resistor of the second comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0010] A liquid-cooled resistor 1 according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration diagram of a cooling system incorporating a liquid-cooled resistor 1 according to one embodiment of the present invention. The liquid-cooled resistor 1 cools a resistor unit 2 by accommodating it in an accommodating space 18 (described later) of a cooling container 4. The liquid is a cooling medium, such as insulating oil, and is filled into the accommodating space 18 until at least the entire resistor unit 2 is immersed in the liquid. An inlet pipe 6 and an outlet pipe 8 through which the liquid flows are connected to the upper wall 4a and the lower wall 4b of the cooling container 4, respectively.

[0011] A pump 10 is installed in the outlet pipe 8, and the inlet of a cooler 12 is connected to the end of the outlet pipe 8 downstream of the pump 10, and the outlet of the cooler 12 is connected to the end of the inlet pipe 6. The liquid heated in the cooling vessel 4 for cooling the resistance unit 2 is discharged from the outlet pipe 8 and sent to the cooler 12 by the pump 10 as shown by the arrows, where it is cooled by heat radiation before flowing through the inlet pipe 6 and returning to the cooling vessel 4. As a result, the liquid circulating in the cooling system flows in and out of the cooling vessel 4 and is circulated, cooling the resistance unit 2.

[0012] Fig. 2 is a schematic side view of the liquid-cooled resistor 1, and Fig. 3 is a schematic top view of the liquid-cooled resistor 1. For the purpose of explanation, Figs. 2 and 3 show the essential parts in a see-through manner. The cooling vessel 4 is a rectangular box surrounded by an upper wall 4a, a lower wall 4b, and four side walls 4c, and an inlet-side partition wall 14 and an outlet-side partition wall 16 are provided inside the box. The inlet-side partition wall 14, with its upper wall 14a and three side walls 14b, defines the inlet side of a housing space 18 in which the resistor unit 2 is housed.

[0013] Specifically, the top wall 14a covers the top wall 4a from below at a location where the inlet pipe 6 is connected, and each side wall 14b extends downward along the opposing side wall 4c. An inlet port 20 for allowing liquid to flow into the accommodation space 18 is formed between the lower end of each side wall 4c and the bottom wall 4b. That is, the inlet port 20 is formed at the bottom of the accommodation space 18 in the vertical direction (up-down direction) Y of the liquid-cooled resistor 1. Note that the left-right direction (direction intersecting the vertical direction Y) in FIG. 2 is defined as the horizontal direction X, and the up-down direction (direction intersecting both the vertical direction Y and the horizontal direction X) in FIG. 3 is defined as the depth direction Z, and the same applies to the subsequent figures.

[0014] On the other hand, the outlet-side partition 16 stands upright from the bottom wall 4b and defines the outlet side of the storage space 18. Specifically, the end faces of the pair of side walls 14b of the inlet-side partition 14 are connected to the outlet-side partition 16, and an outlet port 22 for discharging liquid from the storage space 18 is formed between the upper end of the outlet-side partition 16 and the top wall 4a. That is, the outlet port 22 is formed at the top of the storage space 18 in the vertical direction Y. In the cooling container 4 configured in this manner, the resistance unit 2 is suspended by a bracket (not shown) in a non-contact state from the cooling container 4 and is placed in the storage space 18, and the liquid flows as shown by the dashed arrows in FIG. 2.

[0015] Specifically, the liquid that flows into the cooling container 4 from the inlet pipe 6 flows through an inlet flow path 24 defined between the inlet-side partition 14 and the side wall 4c, and then flows into the accommodation space 18 from the inlet port 20. The liquid that has been used to cool the resistance elements 30 (see FIG. 3 ), which will be described later and which constitute the resistance unit 2, flows from the outlet port 22 through an outlet flow path 26 defined between the outlet-side partition 16 and the side wall 4c, and is discharged from the outlet pipe 8.

[0016] FIG. 4 is a perspective view showing the main parts of the liquid-cooled resistor 1. Note that the upper wall 4a, lower wall 4b, and each side wall 4c of the cooling container 4 are not shown in FIG. 4. The resistor unit 2 includes a plurality of resistor elements 30 that generate heat when current is applied. The resistor elements 30 are strip-shaped electrical conductors whose width is in the vertical direction Y. The resistor elements 30 are electrically connected at terminal portions 40 (described below) and arranged in multiple stages in the vertical direction Y to form a resistor body 32.

[0017] The resistor unit 2 also includes multiple pairs of insulators 34 arranged alternately with the resistor elements 30 in the vertical direction Y. Each insulator 34 supports the resistor element 30 located above it and prevents contact between adjacent resistor elements 30 in the vertical direction Y. As shown in FIGS. 3 and 4 , the liquid-cooled resistor 1 of this embodiment is provided with a flow path resistance member 50 that obstructs the flow of liquid between the resistor element 30 (hereinafter also referred to as 30A) located in the uppermost row in the vertical direction Y and the resistor element 30 (hereinafter also referred to as 30B) located in the row below the uppermost row in the vertical direction Y, at a position facing the outlet-side partition wall 16.

[0018] 5 shows a top view of the resistive element 30. The resistive element 30 includes a resistive portion 36, a pair of extension portions 38, and a pair of terminal portions 40. The resistive portion 36 has a plurality of bent portions 36a and a plurality of straight portions 36b. The bent portions 36a are formed by bending the resistive element 30 approximately 180 degrees in the lateral direction X and folding it back. The straight portions 36b are formed between the bent portions 36a that face each other in the lateral direction X.

[0019] Each extension 38 extends from an end of the resistor 36 facing the outlet-side partition wall 16 toward the outlet-side partition wall 16. Each terminal 40 is formed by bending the corresponding extension 38 at approximately 90 degrees so that the terminals 40 face each other. The resistor 32 shown in FIG. 4 is formed by electrically connecting multiple stacked resistor elements 30 at their terminals 40. Because a high voltage is applied to the resistor elements 30, an insulation distance Lb is ensured between each terminal 40 and the outlet-side partition wall 16, which is sufficient to prevent arc discharge from the resistor elements 30.

[0020] As shown in Fig. 4, the flow path resistance members 50 are positioned between the extension portions 38 of the resistance element 30A and the extension portions 38 of the resistance element 30B. Also, as shown in Fig. 4, the insulators 34 are arranged in pairs, spaced apart from each other, near both ends in the lateral direction X of the same resistance element 30. Furthermore, the flow path resistance members 50 are arranged between the extension portions 38 adjacent to the insulators 34 on the outlet-side partition wall 16 side in the lateral direction X.

[0021] FIG. 6 shows a perspective view of a flow path resistance member 50, and FIG. 7 shows a perspective view of a flow path resistance member 50 according to a modified example. The flow path resistance member 50 is an electrical insulator having a rectangular parallelepiped shape, such as a block of lumber. The flow path resistance member 50 is formed from an elastic material such as rubber. In this case, the flow path resistance member 50 is sandwiched between the extension portions 38 of the resistance elements 30A, 30B adjacent to each other in the longitudinal direction Y. As shown in FIG. 7, slits 52 may be formed on the upper surface 50a and the lower surface 50b of the flow path resistance member 50 at positions where the extension portions 38 of the resistance elements 30A, 30B abut. In this case, the flow path resistance member 50 is positioned and fixed by fitting the slits 52 into the extension portions 38.

[0022] FIG. 8 is a side view illustrating the flow of liquid in the liquid-cooled resistor 1 of this embodiment. For ease of explanation, FIG. 8 and FIGS. 9 and 10 (described later) show a schematic, see-through view of the essential parts. In this embodiment, the flow path resistance member 50 is provided between each extension 38 of the resistor element 30A and each extension 38 of the resistor element 30B. This prevents liquid from flowing in the region A1 below the flow path resistance member 50 and between the outlet-side partition wall 16 and the insulator 34 on the outlet-side partition wall 16 side. This allows a large amount of liquid to flow through the flow path A formed between the insulators 34 arranged in the horizontal direction X, i.e., the resistor 32 and the resistor unit 2, at the center of the horizontal direction X. Therefore, the entire resistor unit 2 can be sufficiently cooled by liquid.

[0023] 9 is a side view illustrating the flow of liquid in the liquid-cooled resistor 1 of the first comparative example. In the first comparative example, the flow path resistance member 50 is not provided, so a large amount of liquid flows through flow path B, which is formed between the outlet-side partition wall 16 and the insulator 34 on the outlet-side partition wall 16 side and has fewer obstacles and lower flow path resistance than flow path A. Therefore, the amount of liquid flowing through flow path A decreases relatively, causing uneven cooling of the resistor unit 2 and making it impossible to sufficiently cool the entire resistor unit 2 with liquid.

[0024] 10 is a side view illustrating the flow of liquid in the liquid-cooled resistor 1 of the second comparative example. In the second comparative example, a flow path resistance member 50 is provided between the resistance element 30 (hereinafter also referred to as 30D) located at the lowest level in the vertical direction Y and the resistance element 30 (hereinafter also referred to as 30C) located at the level above the lowest level in the vertical direction Y, and at a position facing the outlet-side partition wall 16.

[0025] Specifically, a flow path resistance member 50 is provided between each extension portion 38 of the resistor element 30C and each extension portion 38 of the resistor element 30D. Also, the flow of liquid is obstructed in a region A2 below the flow path resistance member 50, between the outlet-side partition wall 16 and the insulator 34 on the outlet-side partition wall 16 side. As a result, above the flow path resistance member 50, the liquid flowing through flow path A is diverted to the flow directions of flow paths C and D. Therefore, the amount of liquid flowing through flow path A is relatively reduced, causing uneven cooling of the resistor unit 2, and the entire resistor unit 2 cannot be sufficiently cooled by the liquid.

[0026] As described above, in the liquid-cooled resistor 1 of this embodiment, the flow path resistance member 50 for impeding the flow of liquid is provided between the resistor element 30A located in the uppermost row in the vertical direction Y and the resistor element 30B located in the row below the uppermost row in the vertical direction Y, at a position facing the outlet-side partition wall 16. This allows a large amount of liquid to flow through the flow path A formed in the center of the resistor 32 and, in turn, the resistor unit 2 in the horizontal direction X, so that the entire resistor unit 2 can be sufficiently cooled by liquid. This improves the cooling performance of the resistor unit 2 and ultimately prevents the resistor unit 2 from becoming abnormally hot.

[0027] Furthermore, the flow path resistance members 50 are positioned between the extension portions 38 of the resistance element 30A and the extension portions 38 of the resistance element 30B. As a result, the flow path resistance members 50 do not come into contact with the resistance portions 36 of each resistance element 30 that particularly require cooling, and the flow of liquid in the resistance portions 36 is not obstructed by the flow path resistance members 50. This reliably improves the cooling performance of the resistance unit 2, and ultimately reliably prevents the resistance unit 2 from becoming abnormally hot.

[0028] Furthermore, the insulators 34 are arranged in pairs spaced apart from each other near both ends in the lateral direction X of the same resistor element 30, and the flow path resistance members 50 are arranged adjacent to the insulators 34 on the outlet-side partition wall 16 side in the lateral direction X between the extension portions 38. This makes it difficult for liquid to flow between the insulators 34 and the flow path resistance members 50, and as shown in Fig. 8, the flow path A and the region A1 can be clearly separated in each insulator 34 on the outlet-side partition wall 16 side. Therefore, more liquid can flow through the flow path A, further improving the cooling performance of the resistor unit 2.

[0029] Furthermore, since the flow path resistance member 50 is an electrical insulator, it is possible to prevent short-circuiting between the resistance elements 30A, 30B caused by the flow path resistance member 50. The flow path resistance member 50 is formed from an elastic material and is sandwiched between the resistance elements 30A, 30B aligned in the vertical direction Y. This allows the flow path resistance member 50 to be positioned and fixed without rattle. The flow path resistance member 50 may also have slits 52 that fit into the resistance elements 30A, 30B aligned in the vertical direction Y. In this case, rattle of the flow path resistance member 50 can be more effectively suppressed, and the flow path resistance member 50 can be positioned and fixed even more easily.

[0030] Although the description of one embodiment of the present invention has been completed above, the present invention is not limited to the above embodiment and various modifications can be made without departing from the spirit of the present invention. For example, the shape and number of resistor elements 30, the number of bent portions 36a in resistor elements 30, the shape and number of insulators 34, the structure of cooling vessel 4, the shape of flow path resistance member 50, etc. are not strictly limited to the contents described and illustrated. [Explanation of symbols]

[0031] 1 Liquid cooled resistor 2 Resistor Unit 4 Cooling container 14 Entrance bulkhead 16 Outlet bulkhead 18 Containment Space 20 inlet port 22 Exit Port 30 Resistor element 30A Resistive element located at the top 30B Resistive element located in the lower row of the top row 32 Resistor 34 Insulator 36 Resistance section 36a Bend part 36b Straight section 38 Extension 40 Terminal section 50 Flow path resistance member 52 Slit X horizontal direction Y vertical direction

Claims

1. A liquid-cooled resistor in which a resistance unit is accommodated in an accommodation space of a cooling container and cooled by liquid, The cooling vessel comprises: an inlet-side partition wall that forms an inlet port at a lower portion of the storage space in the vertical direction, through which the liquid flows into the storage space; an outlet-side partition wall that forms an outlet port for discharging the liquid from the storage space at an upper portion of the storage space in the vertical direction; Equipped with The resistance unit is a resistance element that generates heat when energized; a resistor body configured by arranging the resistive elements in a plurality of stages in the vertical direction while electrically connecting the resistive elements; a plurality of insulators arranged alternately with the resistor elements in the longitudinal direction and supporting each of the resistor elements; Equipped with A liquid-cooled resistor characterized in that a flow path resistance member that obstructs the flow of the liquid is provided between the resistance element located in the uppermost row in the vertical direction and the resistance element located in the row below the uppermost row in the vertical direction, and at a position facing the outlet-side partition.

2. The resistive element is a resistor portion including a plurality of bent portions formed by bending the resistor element at both ends in a horizontal direction intersecting the vertical direction, and a linear portion connecting the bent portions connected in the horizontal direction to each other; a pair of extension portions extending from ends of the pair of linear portions facing the outlet-side partition wall toward the outlet-side partition wall, respectively; a pair of terminal portions formed by bending from each of the extension portions toward the extension portions facing each other, and electrically connecting the resistance elements arranged in a plurality of stages to form the resistor; and 2. The liquid-cooled resistor according to claim 1, wherein the flow path resistance member is positioned between each extension portion of the resistance element located in the uppermost tier and each extension portion of the resistance element located in the tier below the uppermost tier.

3. the insulators are arranged in pairs spaced apart from each other near both ends of the same resistor element in the lateral direction, 3. The liquid-cooled resistor according to claim 2, wherein the flow path resistance member is disposed between the extension portions and adjacent to the insulator on the outlet-side partition wall in the lateral direction.

4. 2. The liquid-cooled resistor according to claim 1, wherein the flow path resistance member is an electrical insulator.

5. 2. The liquid-cooled resistor according to claim 1, wherein the flow path resistance member is made of an elastic material and is sandwiched between the resistance elements arranged in the vertical direction.

6. 2. The liquid-cooled resistor according to claim 1, wherein the flow path resistance member has slits into which the resistance elements aligned in the vertical direction are fitted.

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