Heating device and electric vehicle

Abstract

This heating device may be equipped with a plurality of resistance heating elements arranged in a first direction. The electrical resistance value per unit length of the resistance heating element located in the endmost position in the first direction among the plurality of resistance heating elements arranged in the first direction may be the lowest.

Description

Heating device and electric vehicle

[0001] The technology disclosed in this specification relates to a heating device and an electric vehicle.

[0002] Patent Document 1 discloses a heat exchanger for heating a fluid, which includes a heat transfer tube formed in a spiral shape.

[0003] Japanese Patent Application Laid-Open No. 2021-14971

[0004] In the heat exchanger of Patent Document 1, for example, stagnation may occur in the flow of the heated fluid around a portion of the spirally formed heat transfer tube, which may result in the heated fluid being overheated in that portion. This specification provides a technology that can prevent the heated fluid from being overheated in that portion.

[0005] In a first aspect of the present technology, a heating device may include a plurality of resistance heating parts aligned in a first direction, and among the plurality of resistance heating parts aligned in the first direction, a resistance heating part positioned at an end furthest in the first direction may have the lowest electrical resistance value per unit length.

[0006] With this configuration, the fluid to be heated can be agitated by the resistance heating elements located at the ends in the first direction, which prevents stagnation of the flow of the fluid to be heated around the multiple resistance heating elements and prevents the fluid to be heated from being partially overheated.

[0007] In a second aspect, in the first aspect, the heat generating member having the plurality of resistance heating portions may extend in a spiral shape along the first direction. With this configuration, the spiral heat generating member can prevent the fluid to be heated from being partially overheated.

[0008] In a third aspect, the heating device according to the second aspect may further include a shaft member extending along the first direction inside the spiral heat-generating member. A flow path may be provided between the heat-generating member and the shaft member.

[0009] With this configuration, as the heated fluid flows through the flow path, stagnation of the flow of the heated fluid around the multiple resistance heating elements can be prevented, and partial overheating of the heated fluid can be prevented.

[0010] In a fourth aspect, in the first aspect, the heat generating member having the plurality of resistance heating portions may be configured in a spiral shape with an increasing number of turns along the first direction. With this configuration, the spiral-shaped heat generating member can prevent the heated fluid from being partially overheated.

[0011] In a fifth aspect, in the first aspect, each of the plurality of resistance heating portions may extend linearly in a direction intersecting the first direction. With this configuration, the linear resistance heating portion can prevent the fluid to be heated from being partially overheated.

[0012] In a sixth aspect, an electric vehicle may include the heating device according to any one of the first to fifth aspects. With this configuration, it is possible to prevent the heated fluid used in the electric vehicle from being partially overheated.

[0013] 5. A cross-sectional view of the heating device of the first embodiment. An enlarged view of portion II of FIG. 1. A side view of the heating member of the first embodiment. A side view of the heat-generating member of the first embodiment. A cross-sectional view of the heating device of the second embodiment. A cross-sectional view taken along VI-VI of FIG. 5. A top view of the heat-generating member of the second embodiment. An enlarged view of portion VIII of FIG. 5. A cross-sectional view of the heating device of the third embodiment. A cross-sectional view taken along XX of FIG. 9. An enlarged view of portion XI of FIG. 9.

[0014] First Embodiment A heating device 2 of a first embodiment will be described with reference to the drawings. As shown in FIG. 1 , the heating device 2 of the first embodiment includes a housing 4, and a heating member 50 and a shaft member 40 disposed inside the housing 4. The housing 4 is made of, for example, metal. A flow path 30 is provided inside the housing 4, through which a fluid to be heated (e.g., water or coolant liquid) flows. The fluid to be heated flowing through the flow path 30 functions, for example, as a heat transfer medium for heating an electric vehicle.

[0015] As shown in Fig. 2, the heating element 50 disposed inside the housing 4 includes the heat-generating element 10, a tubular housing 60 that houses the heat-generating element 10, and a powdered insulating material 62 filled between the heat-generating element 10 and the tubular housing 60. As shown in Fig. 3, the heating element 50 is configured in a spiral shape extending along a first direction (in this embodiment, the vertical direction in Figs. 1 and 3). The spiral axis of the heating element 50 extends in the first direction. The heating element 50 is also called a sheathed heater.

[0016] The tubular housing 60 of the heating member 50 is formed by spirally winding a metal tube (e.g., a copper alloy tube). The spiral tubular housing 60 covers the spiral heating member 10. The insulating material 62 filled inside the tubular housing 60 is, for example, magnesium oxide powder.

[0017] The heat-generating member 10 disposed inside the tubular housing 60 is configured in a spiral shape extending along a first direction (in this embodiment, the vertical direction in FIGS. 1, 3, and 4) as shown in Fig. 4. The heat-generating member 10 is configured by spirally winding a metal wire. The spiral axis of the heat-generating member 10 extends in the first direction. The heat-generating member 10 generates heat when electricity is applied.

[0018] The heat-generating member 10 comprises a first portion 12 and a second portion 14 connected to an end of the first portion 12. The second portions 14, 14 are connected to both ends of the first portion 12. The first portion 12 is disposed between the pair of second portions 14, 14. The pair of second portions 14 and the first portion 12 are continuously connected in the axial direction of the heat-generating member 10. The pair of second portions 14 and the first portion 12 are integrally configured.

[0019] The first portion 12 is made of a first type of metal wire (for example, nichrome wire) that is wound in a spiral shape.

[0020] The second portion 14 is made of a second type of metal wire (e.g., stainless steel wire) that is different from the first type of metal wire. The second portion 14 is made by winding the second type of metal wire in a spiral shape.

[0021] The electrical resistance per unit length of the first type metal wire constituting the first portion 12 is higher than the electrical resistance per unit length of the second type metal wire constituting the second portion 14. (The electrical resistance per unit length of the second type metal wire is lower than the electrical resistance per unit length of the first type metal wire.) Therefore, when heat-generating member 10 generates heat by passing current through it, the heat generation temperature of first portion 12 becomes higher than the heat generation temperature of second portion 14. (The heat generation temperature of second portion 14 becomes lower than the heat generation temperature of first portion 12.)

[0022] The heat-generating member 10 further includes a third portion 16 connected to an end of the second portion 14. An insulator 18 is attached to the third portion 16 to prevent electrical connection between the heat-generating member 10 and the tubular housing 60 (see FIG. 2). Insulators 18 are attached to each of the third portions 16 at both ends of the heat-generating member 10. The third portions 16 at both ends of the heat-generating member 10 are electrically connected to an external power source (not shown), and power is supplied to the heat-generating member 10 from the external power source via the third portions 16 at both ends of the heat-generating member 10.

[0023] The spiral heat generating member 10 has a plurality of resistance heating portions 22, 24 aligned in a first direction (in this embodiment, the vertical direction in FIG. 4 ). More specifically, the heat generating member 10 has at least one (e.g., 12) first resistance heating portion 22 and at least one (e.g., two) second resistance heating portion 24 aligned in the first direction.

[0024] The first resistance heating portion 22 is located closer to the center in the axial direction of the heat generating member 10 than the second resistance heating portion 24. The second resistance heating portion 24 is located closer to the end in the axial direction of the heat generating member 10 than the first resistance heating portion 22. The second resistance heating portions 24, 24 are arranged at both ends in the axial direction of the heat generating member 10. At least one (e.g., 12) first resistance heating portion 22 is arranged between the second resistance heating portions 24, 24 at both ends.

[0025] The first resistive heating portion 22 corresponds to a part of the first portion 12 of the heat-generating member 10. One first resistive heating portion 22 corresponds to one turn of the spiral-shaped heat-generating member 10. The first portion 12 of the heat-generating member 10 includes at least one (e.g., 12) first resistive heating portion 22. The first resistive heating portion 22 is made of a first type of metal wire. The electrical resistance per unit length of the first resistive heating portion 22 is higher than the electrical resistance per unit length of the second resistive heating portion 24. Therefore, when the heat-generating member 10 generates heat by passing current through it, the heat generation temperature of the first resistive heating portion 22 becomes higher than the heat generation temperature of the second resistive heating portion 24.

[0026] The second resistance heating portion 24 corresponds to a part of the second portion 14 of the heat-generating member 10. One second resistance heating portion 24 corresponds to one turn of the spiral-shaped heat-generating member 10. The second portions 14, 14 at both ends of the heat-generating member 10 each include at least one (e.g., one) second resistance heating portion 24. The second resistance heating portion 24 is made of a second type of metal wire. The electrical resistance per unit length of the second resistance heating portion 24 is lower than the electrical resistance per unit length of the first resistance heating portion 22. Therefore, when the heat-generating member 10 generates heat by passing current through it, the heat generation temperature of the second resistance heating portion 24 is lower than the heat generation temperature of the first resistance heating portion 22.

[0027] The heating member 50 including the heat-generating member 10 is disposed in the flow path 30 inside the housing 4 (see FIG. 1). The heating member 50 heats the fluid to be heated that flows through the flow path 30. The heating member 50 heats the fluid to be heated by the heat generated by the heat-generating member 10.

[0028] The heating member 50 also surrounds the axial core member 40, which is disposed inside the housing 4 (see FIG. 1). The axial core member 40 is disposed inside the spiral heating member 50. The axial core member 40 is made of, for example, a rod-shaped metal. The axial core member 40 is configured in a cylindrical shape. The axial core member 40 extends along a first direction (the up-and-down direction in FIG. 1 in this embodiment). The axial core member 40 extends in the axial direction of the heating member 50 and the heat-generating member 10. Both axial ends of the axial core member 40 protrude outward in the axial direction beyond both axial ends of the heating member 50.

[0029] Next, the flow path 30 through which the heated fluid flows will be described. The flow path 30 for the heated fluid provided inside the housing 4 includes an upstream flow path 36, an inner flow path 32, an outer flow path 34, and a downstream flow path 38.

[0030] The upstream flow path 36 is provided above the upper end of the heating member 50 in the axial direction. The upstream flow path 36 is provided upstream of the heating member 50 in the flow direction of the fluid to be heated. The fluid to be heated is introduced into the upstream flow path 36 from an inlet 31 provided in the housing 4. The fluid to be heated is introduced into the upstream flow path 36 in a direction perpendicular to the axial direction of the heating member 50. The upstream flow path 36 is connected to the inner flow path 32 and the outer flow path 34. The fluid to be heated that has flowed through the upstream flow path 36 flows into the inner flow path 32 and the outer flow path 34.

[0031] The inner flow path 32 is provided between the inner circumferential surface 50a of the spiral heating member 50 and the outer circumferential surface 40b of the rod-shaped shaft member 40 (see FIG. 2). The inner flow path 32 is provided between the spiral heating member 10 and the rod-shaped shaft member 40. The inner flow path 32 extends in a first direction (the vertical direction in FIGS. 1 and 2 in this embodiment). The inner flow path 32 extends in the axial direction of the heating member 50 (and the axial direction of the shaft member 40). The width W32 of the inner flow path 32 (i.e., the width between the inner circumferential surface 50a of the spiral heating member 50 and the outer circumferential surface 40b of the rod-shaped shaft member 40) is wider than the width W50 between adjacent portions of the heating member 50 in the axial direction.

[0032] The heated fluid flowing through the inner flow path 32 flows along the axial direction of the heating member 50 (and the axial direction of the shaft member 40). That is, the heated fluid flows along a first direction. The heated fluid flows along the direction in which the multiple resistance heating portions 22, 24 (see FIG. 4) of the heat-generating member 10 are aligned.

[0033] The outer flow path 34 is provided between the outer peripheral surface 50b of the spiral heating member 50 and the inner peripheral surface 4a of the housing 4 (see FIG. 2). The outer flow path 34 is provided between the spiral heat-generating member 10 and the housing 4. The outer flow path 34 extends along a first direction (the vertical direction in FIGS. 1 and 2 in this embodiment). The outer flow path 34 extends along the axial direction of the heating member 50 (and the axial direction of the shaft member 40). The width W34 of the outer flow path 34 (i.e., the width between the outer peripheral surface 50b of the spiral heating member 50 and the inner peripheral surface 4a of the housing 4) is wider than the width W50 between adjacent portions of the heating member 50 in the axial direction. The width W34 of the outer flow path 34 may be the same as or different from the width W32 of the inner flow path 32.

[0034] The heated fluid flowing through the outer flow path 34 flows along the axial direction of the heating member 50 (and the axial direction of the shaft member 40). That is, the heated fluid flows along a first direction. The heated fluid flows along the direction in which the multiple resistance heating portions 22, 24 (see FIG. 4) of the heat generating member 10 are aligned.

[0035] The downstream flow path 38 is located below the lower end of the heating member 50 in the axial direction (see FIG. 1 ). The downstream flow path 38 is located downstream of the heating member 50 in the flow direction of the heated fluid. The downstream flow path 38 is connected to the inner flow path 32 and the outer flow path 34. The heated fluid that has flowed through the inner flow path 32 and the outer flow path 34 flows into the downstream flow path 38. The heated fluid that has flowed through the downstream flow path 38 is discharged to the outside of the housing 4 from an outlet 39 provided in the housing 4. The heated fluid flows out of the housing 4 in a direction perpendicular to the axial direction of the heating member 50.

[0036] (Effects) The first embodiment has been described above. As described above, the heating device 2 of the first embodiment includes a plurality of resistance heating portions (first resistance heating portion 22 and second resistance heating portion 24) aligned in a first direction. Of the plurality of resistance heating portions 22, 24 aligned in the first direction, the resistance heating portion located at the end furthest in the first direction (second resistance heating portion 24) has the lowest electrical resistance value.

[0037] With this configuration, the second resistance heating portion 24 is located at the extreme end in the first direction, so the heated fluid flowing through the flow path 30 can be agitated in this portion. This eliminates stagnation in the flow and prevents the heated fluid from being partially overheated. This prevents the heated fluid from partially boiling. This technology is particularly effective when the heated fluid needs to be heated but not boiled.

[0038] The heat generating member 10, which includes the plurality of resistance heating portions 22, 24, extends spirally along the first direction. With this configuration, the spiral heat generating member 10 can prevent the fluid to be heated from being partially overheated.

[0039] The heating device 2 also includes an axial core member 40 that extends along the first direction inside the spiral heat-generating member 10. A flow path 30 is provided between the heat-generating member 10 and the axial core member 40. With this configuration, the fluid to be heated flows through the flow path 30, which prevents stagnation of the flow of the heated fluid around the multiple resistance heating portions 22, 24, and prevents the heated fluid from being partially overheated.

[0040] Although the first embodiment has been described above, the configuration of the heating device 2 is not limited to the above embodiment. In the following description, detailed description of the same configuration as that described above may be omitted.

[0041] Second Example In the first example described above, the heating member 50 and the heat-generating member 10 were configured in a spiral shape, but this configuration is not limiting. In the second example, as shown in Figures 5 to 7, the heating member 50 and the heat-generating member 10 are configured in a spiral shape. The heating member 50 and the heat-generating member 10 are configured in a spiral shape with the number of turns increasing along a first direction (the left-right direction in Figures 5 to 7 in this example). The heating member 50 and the heat-generating member 10 are configured in a spiral shape with the first direction as the radial direction.

[0042] The tubular housing 60 of the heating member 50 is formed by spirally winding a metal tube (e.g., a copper alloy tube). The spiral tubular housing 60 covers the spiral heat-generating member 10. The heat-generating member 10 is formed by spirally winding a metal wire.

[0043] The heat-generating member 10 comprises a first portion 12 and a second portion 14 connected to an end of the first portion 12. The second portions 14, 14 are connected to both ends of the first portion 12. The first portion 12 is disposed between the pair of second portions 14, 14. The pair of second portions 14 and the first portion 12 are continuously connected. The pair of second portions 14 and the first portion 12 are integrally formed.

[0044] The first portion 12 is made of a first type of metal wire (for example, nichrome wire) that is wound in a spiral shape.

[0045] The second portion 14 is made of a second type of metal wire (e.g., stainless steel wire) that is different from the first type of metal wire. The second portion 14 is made by winding the second type of metal wire in a spiral shape.

[0046] The spiral-shaped heat generating member 10 includes a plurality of resistance heating portions 22, 24 aligned in a first direction. More specifically, the heat generating member 10 includes at least one (e.g., four) first resistance heating portion 22 and at least one (e.g., two) second resistance heating portion 24 aligned in the first direction.

[0047] The second resistance heating portions 24 are located radially inward and outward of the first resistance heating portions 22 of the heat generating member 10. The second resistance heating portions 24, 24 are arranged at both radial ends of the heat generating member 10. At least one first resistance heating portion 22 is arranged between the second resistance heating portions 24, 24 at both ends.

[0048] The first resistive heating portion 22 corresponds to a part of the first portion 12 of the heat-generating member 10. One first resistive heating portion 22 corresponds to one turn of the spiral-shaped heat-generating member 10. The first portion 12 of the heat-generating member 10 includes at least one (e.g., four) first resistive heating portion 22. The first resistive heating portion 22 is made of a first type of metal wire. The electrical resistance per unit length of the first resistive heating portion 22 is higher than the electrical resistance per unit length of the second resistive heating portion 24. Therefore, when the heat-generating member 10 generates heat by passing current through it, the heat generation temperature of the first resistive heating portion 22 becomes higher than the heat generation temperature of the second resistive heating portion 24.

[0049] The second resistance heating portion 24 corresponds to a part of the second portion 14 of the heat generating member 10. One second resistance heating portion 24 corresponds to one turn of the spiral-shaped heat generating member 10. The second portions 14, 14 at both ends of the heat generating member 10 each include at least one (e.g., one) second resistance heating portion 24. The second resistance heating portion 24 is made of a second type of metal wire. The electrical resistance per unit length of the second resistance heating portion 24 is lower than the electrical resistance per unit length of the first resistance heating portion 22. Therefore, when the heat generating member 10 generates heat due to electrical current passing through it, the heat generation temperature of the second resistance heating portion 24 is lower than the heat generation temperature of the first resistance heating portion 22.

[0050] The heating member 50 including the heat-generating member 10 is disposed in the flow path 30 inside the housing 4 of the heating device 2. The flow path 30 includes an upstream flow path 136, an upper flow path 132, a lower flow path 134, and a downstream flow path 38.

[0051] The upstream flow path 136 is provided inside the radially inner end of the heating member 50. The fluid to be heated is introduced into the upstream flow path 136 from an inlet 131 provided in the housing 4. The fluid to be heated is introduced into the upstream flow path 136 along a direction perpendicular to the radial direction of the heating member 50. The upstream flow path 136 is connected to the upper flow path 132 and the lower flow path 134. The fluid to be heated that flows through the upstream flow path 136 flows into the upper flow path 132 and the lower flow path 134.

[0052] The upper flow passage 132 is provided between the upper surface 50c of the spiral heating member 50 and the lower surface 42b of the upper member 42 of the housing 4 (see FIG. 8). The upper flow passage 132 is provided between the spiral heat-generating member 10 and the upper member 42 of the housing 4. The upper flow passage 132 extends in the first direction (the left-right direction in FIGS. 5 and 8 in this embodiment). The upper flow passage 132 extends in the radial direction of the heating member 50. The width W132 of the upper flow passage 132 (i.e., the width between the upper surface 50c of the spiral heating member 50 and the lower surface 42b of the upper member 42 of the housing 4) is wider than the width W50 between adjacent portions of the heating member 50 in the radial direction.

[0053] The fluid to be heated that flows through the upper flow passage 132 flows along the radial direction of the heating member 50. That is, the fluid to be heated flows along the first direction. The fluid to be heated flows along the direction in which the multiple resistance heating portions 22, 24 (see FIG. 7) of the heat generating member 10 are aligned.

[0054] The lower flow path 134 is provided between the lower surface 50d of the spiral heating member 50 and the upper surface 44a of the lower member 44 of the housing 4 (see FIG. 8 ). The lower flow path 134 is provided between the spiral heating member 10 and the lower member 44 of the housing 4. The lower flow path 134 extends along the first direction (the left-right direction in FIGS. 5 and 8 in this embodiment). The lower flow path 134 extends along the radial direction of the heating member 50. The width W134 of the lower flow path 134 (i.e., the width between the lower surface 50d of the spiral heating member 50 and the upper surface 44a of the lower member 44 of the housing 4) is wider than the width W50 between adjacent portions of the heating member 50 in the radial direction. The width W134 of the lower flow path 134 may be the same as or different from the width W132 of the upper flow path 132.

[0055] The heated fluid flowing through the lower flow path 134 flows along the radial direction of the heating member 50. That is, the heated fluid flows along the first direction. The heated fluid flows along the direction in which the multiple resistance heating portions 22, 24 (see FIG. 7) of the heat generating member 10 are aligned.

[0056] The downstream flow path 138 is provided downstream of the heating member 50 in the flow direction of the heated fluid (see FIG. 6 ). The downstream flow path 138 is connected to the upper flow path 132 and the lower flow path 134. The heated fluid that has flowed through the upper flow path 132 and the lower flow path 134 flows into the downstream flow path 138. The heated fluid that has flowed through the downstream flow path 138 is discharged to the outside of the housing 4 from an outlet 139 provided in the housing 4.

[0057] The second embodiment has been described above. As described above, in the heating device 2 of the second embodiment, the heat generating member 10 including the multiple resistance heat generating portions 22, 24 is configured in a spiral shape with an increasing number of turns along the first direction. With this configuration, the spiral heat generating member 10 can prevent the heated fluid from being partially overheated.

[0058] (Third Example) In the first example described above, the heating member 50 and the heat-generating member 10 are configured in a spiral shape, but this configuration is not limiting. In a third example, as shown in Figures 9 and 10, the heating member 50 and the heat-generating member 10 are configured in a linear shape. The heating device 2 of the third example includes multiple linear heating members 50. A tubular housing 60 for each linear heating member 50 covers each linear heat-generating member 10. The multiple linear heating members 50 are arranged in a flow path 30 inside the housing 4.

[0059] The plurality of heating members 50 and the plurality of heat-generating members 10 are each configured in a linear shape extending in a direction perpendicular to the first direction (in this embodiment, the left-right direction in FIGS. 9 and 10 ). The plurality of heating members 50 and the plurality of heat-generating members 10 are arranged side by side in the first direction.

[0060] The plurality of heat-generating members 10 aligned in the first direction each include a plurality of resistance heat-generating portions 22, 24. More specifically, of the plurality of heat-generating members 10 aligned in the first direction, the heat-generating member 10b located at the end furthest in the first direction (hereinafter referred to as the "second heat-generating member 10b") includes a second resistance heat-generating portion 24. Furthermore, of the plurality of heat-generating members 10 aligned in the first direction, a plurality (e.g., seven) of heat-generating members 10a (hereinafter referred to as the "first heat-generating members 10a") located between the second heat-generating members 10b at both ends in the first direction each include a first resistance heat-generating portion 22.

[0061] The first resistance heating portion 22 of the first heat-generating member 10a is made of a first type of metal wire (e.g., nichrome wire). The electrical resistance per unit length of the first resistance heating portion 22 is higher than the electrical resistance per unit length of the second resistance heating portion 24. Therefore, when the heat-generating member 10 generates heat by passing electricity through the first resistance heating portion 22, the heat temperature of the first resistance heating portion 22 becomes higher than the heat temperature of the second resistance heating portion 24.

[0062] The second resistance heating portion 24 of the second heat-generating member 10b is made of a second type of metal wire (e.g., stainless steel wire). The electrical resistance per unit length of the second resistance heating portion 24 is lower than the electrical resistance per unit length of the first resistance heating portion 22. Therefore, when the heat-generating member 10 generates heat by passing electricity through the second resistance heating portion 24, the heat generation temperature of the second resistance heating portion 24 becomes lower than the heat generation temperature of the first resistance heating portion 22.

[0063] The heating member 50 including the heat-generating member 10 is disposed in the flow path 30 inside the housing 4 of the heating device 2. The flow path 30 includes an upstream flow path 236, an upper flow path 232, a lower flow path 234, and a downstream flow path 38.

[0064] The upstream flow path 236 is provided upstream of the heating member 50 in the flow direction of the fluid to be heated. The fluid to be heated is introduced into the upstream flow path 236 from an inlet 231 provided in the housing 4. The fluid to be heated is introduced into the upstream flow path 236 in a direction perpendicular to the direction in which the multiple heating members 50 are arranged. The upstream flow path 236 is connected to the upper flow path 232 and the lower flow path 234. The fluid to be heated that has flowed through the upstream flow path 236 flows into the upper flow path 232 and the lower flow path 234.

[0065] The upper flow path 232 is provided between the upper surface 50c of the linear heating member 50 and the lower surface 42b of the upper member 42 of the housing 4 (see FIG. 11). The upper flow path 232 is provided between the linear heat-generating member 10 and the upper member 42 of the housing 4. The upper flow path 232 extends along the first direction (the left-right direction in FIGS. 9 and 11 in this embodiment). The upper flow path 232 extends along the direction in which the multiple heating members 50 are arranged. The width W232 of the upper flow path 232 (i.e., the width between the upper surface 50c of the linear heating member 50 and the lower surface 42b of the upper member 42 of the housing 4) is wider than the width W50 between adjacent heating members 50.

[0066] The fluid to be heated that flows through the upper flow path 232 flows in the direction in which the multiple heating members 50 are arranged. That is, the fluid to be heated flows in the first direction. The fluid to be heated flows in the direction in which the multiple resistance heating portions 22, 24 (see FIG. 10 ) are arranged.

[0067] The lower flow path 234 is provided between the lower surface 50d of the linear heating member 50 and the upper surface 44a of the lower member 44 of the housing 4 (see FIG. 11 ). The lower flow path 234 is provided between the linear heat-generating member 10 and the lower member 44 of the housing 4. The lower flow path 234 extends along the first direction (the left-right direction in FIGS. 9 and 11 in this embodiment). The lower flow path 234 extends along the direction in which the multiple heating members 50 are arranged. The width W234 of the lower flow path 234 (i.e., the width between the lower surface 50d of the linear heating member 50 and the upper surface 44a of the lower member 44 of the housing 4) is wider than the width W50 between adjacent heating members 50. The width W234 of the lower flow path 234 may be the same as or different from the width W232 of the upper flow path 232.

[0068] The fluid to be heated that flows through the lower flow path 234 flows in the direction in which the multiple heating members 50 are arranged. That is, the fluid to be heated flows in the first direction. The fluid to be heated flows in the direction in which the multiple resistance heating portions 22, 24 (see FIG. 10 ) are arranged.

[0069] The downstream flow path 238 is provided downstream of the heating member 50 in the flow direction of the heated fluid (see FIG. 9 ). The downstream flow path 238 is connected to the upper flow path 232 and the lower flow path 234. The heated fluid that has flowed through the upper flow path 232 and the lower flow path 234 flows into the downstream flow path 238. The heated fluid that has flowed through the downstream flow path 238 is discharged to the outside of the housing 4 from an outlet 239 provided in the housing 4. The heated fluid flows out to the outside of the housing 4 in a direction perpendicular to the direction in which the multiple heating members 50 are arranged.

[0070] The third embodiment has been described above. As described above, the heating device 2 of the third embodiment includes a plurality of resistance heating portions (first resistance heating portion 22 and second resistance heating portion 24) aligned in a first direction. Of the plurality of resistance heating portions 22, 24 aligned in the first direction, the resistance heating portion (second resistance heating portion 24) located at the end furthest in the first direction has the lowest electrical resistance per unit length. Each of the plurality of resistance heating portions 22, 24 extends linearly in a direction intersecting the first direction. With this configuration, the linear resistance heating portions 22, 24 can prevent the heated fluid from being partially overheated.

[0071] (Modifications) (1) The heating device 2 may include a resistance heating portion other than the first resistance heating portion 22 and the second resistance heating portion 24 arranged in the first direction. Even in this case, among the multiple resistance heating portions arranged in the first direction, the resistance heating portion (second resistance heating portion 24) located at the endmost position in the first direction has the lowest electrical resistance value per unit length.

[0072] (2) The heating device 2 may be mounted on an automobile (e.g., an electric automobile, a hybrid automobile, a gasoline automobile, etc.). For example, the heating device 2 may be used to heat a heat medium in a heating system of the automobile. This configuration can improve the accuracy of temperature control of the heated fluid (heat medium) used in the automobile.

[0073] Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives itself has technical utility.

[0074] 2: Heating device, 4: Housing, 10: Heat generating member, 12: First portion, 14: Second portion, 16: Third portion, 18: Insulator, 22: First resistance heating portion, 24: Second resistance heating portion, 30: Flow path, 32: Inner flow path, 34: Outer flow path, 36: Upstream flow path, 38: Downstream flow path, 40: Axial member, 50: Heating member

Claims

1. A heating device having a plurality of resistive heating parts arranged in a first direction, wherein, among the plurality of resistive heating parts arranged in the first direction, the resistive heating part located at the end furthest end in the first direction has the lowest electrical resistance value per unit length.

2. A heating device according to claim 1, wherein the heat generating member having a plurality of said resistance heating portions extends in a spiral shape along said first direction.

3. A heating device as claimed in claim 2, further comprising an axial core member extending along the first direction inside the spiral heat generating member, and a flow path being provided between the heat generating member and the axial core member.

4. A heating device according to claim 1, wherein the heat generating member having a plurality of said resistance heating portions is configured in a spiral shape with an increasing number of turns along said first direction.

5. A heating device according to claim 1, wherein each of the plurality of resistive heating parts extends linearly in a direction intersecting the first direction.

6. An electric vehicle equipped with the heating device according to claim 1 or 2.

Images