JP2776745B2 - Heating equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device. 2. Description of the Related Art A conventional heating device of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 56-160786. This is achieved by combining a plate-shaped ceramic heating element having a positive temperature coefficient of resistance and a heat-dissipating block having a plurality of passages, thermally connecting them together, and integrating the heat-dissipating portion with a metal. It is a structure fixed inside the frame body made of. [0003] The present invention has been made in view of the fact that, when the above-described heating device is disposed in a passage, the air flow distribution in the passage is large at the center portion and is reduced toward the end. It is another object of the present invention to provide a heating device that allows a medium to be heated such as air to pass through a passage portion of a heat radiation block in accordance with the flow rate distribution. SUMMARY OF THE INVENTION [0004] In view of the above, the present invention generates heat when energized and has a positive temperature resistance coefficient.
Also a plurality of heating elements in which one side of each other form a oppositely disposed plate-like shape, is disposed between opposing said plurality of heating elements, meander
Radiation fins bent in the shape of a circle, and both sides of the radiation fins
And a heat transfer plate joined to the bent end of the
A plurality of passages for passing the medium to be heated are
First heat radiation blocks formed between the meandering portions of
And the plurality of heat sources together with the first heat dissipation block.
It is arranged on almost the entire surface between the opposing bodies and is formed to bend in a meandering shape
Radiating fins and the heat transfer fins of the first radiating block.
The heat radiation fins are in contact with the bent ends on both sides.
And a heat transfer plate
Multiple passages between the meandering parts of the radiating fins
Sandwiched by the first heat radiation block formed
A second inner heat dissipating block, and an outer heat dissipating block disposed on substantially the entire surface on the other side opposite to the one side of the plurality of heating elements, and having a plurality of passages for passing a medium to be heated, A case having a rectangular shape that accommodates the heating element, the first and second inner heat radiating blocks, and the outer heat radiating block so that the passage portions of the inner heat radiating block and the outer heat radiating block are opened in a rectangular shape. Wherein the total opening area of the passage portion opened by the case of the first and second inner heat dissipation blocks is the total opening area of the passage portion opened by the case of the outer heat dissipation block. That is, a technical means that the setting is made larger than that is adopted. According to the present invention, in consideration of the fact that the flow rate distribution of the medium to be heated in the passage is generally large at the center and smaller as approaching the end, each of the inner radiators disposed between the plate-shaped heating elements is provided. By making the total opening area of the passage portion opened by the case of the block larger than the total opening area of the passage portion opened by the case of each outer heat dissipation block, it is possible to increase the flow rate of the medium to be heated to the inner heat dissipation block. Therefore, it is possible to suppress a decrease in the heat generation efficiency due to the heat of the heating element being collected in the heat radiation block and having a characteristic of a positive temperature resistance coefficient. Furthermore, since each heat dissipation block is housed in a rectangular case so as to open in a rectangular shape, the heat dissipation block can be arranged on substantially the entire side surface of the heating element. Therefore, not only can the contact area between the heating element and the inner and outer heat dissipation blocks be increased, but also the passage portions of the inner and outer heat dissipation blocks can be increased. Therefore, the heat of the radiator can be effectively transmitted to the medium to be heated flowing through the passage of the radiator block. Even better
Also, in the present invention, the inner heat dissipation block is first and second.
And a second inner heat dissipation block, a second heat dissipation block
Is sandwiched between the first heat dissipation block and the heat transfer plate.
Configuration. Therefore, the inner heat radiation block
If only the opening area is increased,
Heat is easily trapped in the central part, and is plate-shaped by the heat transfer plate
That can achieve uniform heat in the direction parallel to the heating element
A thermal device can be obtained. Accordingly, in the present invention, the heat of the heat radiating portion can be effectively transmitted to the medium to be heated flowing through the passage of the heat radiating block, and the heating effect of the medium to be heated is enhanced. be able to. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings. FIG. 1 is a front view showing a configuration of an intake air heating device for a diesel engine according to one embodiment of the present invention, and FIG.
3 is a cross-sectional view taken along the line BB of FIG. In these figures, reference numeral 1 denotes four PTC elements formed in a rectangular flat plate having a thickness of 2 mm, and two PTC elements are arranged in two rows. The PTC element 1 generates heat when energized, and is made of a material having a positive temperature resistance coefficient, such as a barium titanate (BaTiO ₃ ) -based ceramic sintered body, whose electric resistance increases significantly with an increase in temperature. I have. A heat radiation block 2 is a rectangular heat radiation block. The heat radiation block 2 has meandering heat radiation fins 2a made of copper or aluminum, and copper or solder joined to the bent ends on both sides of the heat radiation fins 2a. And a flat plate 2b made of aluminum. The heat-dissipating block is thermally coupled to the PTC element 1 by the soldering. As shown in the figure, a passage portion through which intake air as a medium to be heated passes is formed between the meandering portions of the heat radiation fins 2a of the heat radiation block 2. Note that, as shown in FIG. 3, a louver 2′a cut and raised in a direction perpendicular to the intake air flow direction A is provided on the surface of the heat radiation fin 2a of the heat radiation block 2 so that the heat conduction area is increased. It is composed. The heat radiating block 2 is a pre-press of the first heat radiating block 200.
The second heat radiating block 210 is sandwiched via the port 2b.
As described above, three rows are arranged, and the PTC elements 1 are arranged on both sides of the three rows. One row of heat radiation blocks 2 are arranged on both outer sides of the PTC element 1. The graphite filler layer 1a, which is a heat and electric conductive elastic body, is disposed between the PTC element 1 and the plate 2b of the heat radiation block 2 disposed on both outer sides of the PTC element 1. (See FIG. 5). Here, as is apparent from FIG.
The relationship between the opening area of the passage portion between the three rows of inner heat dissipation blocks 2 arranged between two rows of PTC elements 1 and the other row of the outer heat dissipation blocks 2 opposite to the PTC elements 1 is determined by the relationship between the inner heat dissipation blocks. The total opening area of each of the plurality of passage portions is set larger than the total opening area of each of the plurality of passage portions of each outer heat radiation block 2. This is because, as understood from FIG. 1, the bending width dimensions of the heat radiation fins 2 a of the inner heat radiation block 2 and the outer heat radiation block 2 are substantially the same, and the total bending width of the heat radiation fins 2 a of the inner heat radiation block 2. Is set to be dimensionally larger than the bending width of the radiation fin 2a of the outer radiation block 2. Incidentally, the total bending width of the heat radiation fins 2a of the inner heat radiation block 2 is about three times the bending width of the heat radiation fins 2a of the outer heat radiation block 2. Reference numeral 3 denotes a case having a rectangular shape made of a heat-resistant resin such as PPS or ceramics.
, A lower case 3a having a shape obtained by removing one side surface of a flat rectangular box, and a cover 3b having an L-shaped cross section
And a box-like shape combining the above. The surface of the case 3 in the direction perpendicular to the plane of the paper in FIG. 1 leaves a central portion bridging the outer periphery of the heat radiation nest and its intermediate portion so as to open the passage formed in the heat radiation block. A rectangular opening 3c is formed and has a frame-like shape as a whole. The heat radiating portion composed of the PTC element 1 and the heat radiating block 2 is housed in the case 3. The heat dissipating portion has a substantially square planar shape as is apparent from FIG. Reference numeral 4 denotes an aluminum housing having a frame-like shape. The case 3 is housed inside the housing 4, and a space 4 formed between one side surface 4 a of the housing 4 and the side surface 3 ′ b of the cover 3 b of the case 3.
Inside b, a U-shaped spring 5 to which a restoring force is applied in a spreading direction is arranged. The side surface 3'b of the case 3b is pressed by the restoring force of the spring 5, and the PTC element 1 and the heat radiation block 2 are moved between the side surface 3'b and the end surface 3'a of the lower case 3a opposed thereto. Pressed and fixed at once. A support portion 4e for supporting the heat radiating portion is formed at one end of the opening 4c of the housing 4. The heat radiating portion is supported by the support portion 4e via the case 3. A positive terminal 2c is drawn out from one of the heat transfer plates 2b in the three rows of the inner heat radiating blocks 2 through a not-shown notch in the lower case 3a. The terminal 2c is bent along the side surface of the frame 3d of the lower case 3a, and the terminal 2c is electrically connected to the housing 4 at the bent portion by the bolt 6a and the nut 6b via the frame 3d and the insulator ring 6c. Insulated and fixed. As a result, the lower case 3a is fixed to the housing 4 via the frame 3d. Further, from the outermost heat transfer plates 2b of the outer heat radiation blocks 2 arranged in one row, minus terminals 2d located in opposite directions to the terminals 2c are drawn out of the lower case 3a. The terminal 2d
Is mounted on the shelf 3e of the lower case 3a, is fixed to the housing 4 via small screws 7, and is electrically connected to the housing 4. Reference numeral 8 denotes a clip for fixing the cover 3b to the housing 4, and the clip 8 connects the projection 3f of the upper case 3b to the housing 4 as is apparent from FIGS.
The projection 3f is fitted from above on the supporting portion 4d. The clip 3 allows the case 3 to be
It will be fixed in the direction perpendicular to the paper surface. By fixing the cover 3b to the housing 4 in this manner, the heat radiating portion is sandwiched between the support portion 4e of the housing 4 and the cover 3b. As a result, the heat radiating portion passes through the medium to be heated. The housing 4 moves in the direction
From falling off. Therefore, the cover 3b
Constitutes a regulating means for regulating the movement of the heat radiating portion. FIG . 4 shows an intake air heating apparatus 1 having the above configuration .
1 shows a state where 0 is attached to an intake system of a diesel engine. The housing 4 of the heating device 10 is arranged so that the intake manifold 13 between the engine 11 and the air cleaner 12 is traversed by the heat radiating portion of the heating device 10, that is, the flow direction of the intake air coincides with the direction of arrow A in FIG. 3. And is configured to warm the intake air. In the drawing, 14 is an engine piston, 15 is a cylinder chamber, 16 is an intake / exhaust valve, and 17 is a fuel injection nozzle. Next, the operation will be described. The current supplied from the battery (not shown) is positive terminal 2
c, flows through the PTC element 1 in the thickness direction through the inner heat dissipation block 2, reaches the minus side terminal 2 d via the outer heat dissipation block 2, and reaches the housing 4 via the small screw 7.
Grounded. The current flows through the above path and the PT
The C element 1 generates heat, and this heat is transmitted to the heat radiation block 2. On the other hand, the intake air flows through a passage formed between the radiation fins 2a and is heated by receiving heat. In this embodiment, since the above-described configuration is provided, the following operation is provided.
That is, since the heat radiating portion is fixed to the metal housing 4 via the case 3 made of heat-resistant resin or ceramic, the case 3 can block the transfer of the heat of the heat radiating portion to the housing 4. The heat of the section can be effectively transmitted to the intake air. The free end of the terminal 2c provided on the inner heat radiating block 2 of the heat radiating portion is bent substantially U-shaped along the inner wall of the housing 4, and the free end is fixed to the inner wall of the housing 4. The terminal 2c can be provided with a spring property by the bent shape of the terminal 2c, and the terminal 2c can be securely fixed to the housing 4, and the heat radiating portion can be held in the housing 4 by the spring property. The total opening area of the passages opened by the cases of the first and second inner heat dissipation blocks 2 is set larger than the total opening area of the passages opened by the cases 3 of each outer heat dissipation block 2. did. Further , the heat dissipation block 2 was accommodated in a rectangular case 3. In addition, the second
The side heat dissipation block 210 is connected to the first inside via the plate 2b.
It was configured to be held by the side heat dissipation block 200. Therefore, not only the amount of intake air passing through the passage portions of the first and second inner heat dissipation blocks 2 can be increased, but also the heat generated by the PTC element 1 can be efficiently transmitted to the heat dissipation blocks. As a result, the heat generated by the PTC element 1 is effectively transmitted to the intake air via the first and second inner heat dissipation blocks 2, so that the PTC element 1 does not reach the self-control temperature and the PTC element 1 The heat generation of the PTC element 1 is not hindered, and the heat generation of the PTC element 1 can be used efficiently. That is, in general, the flow rate distribution of the fluid in the passage has a mountain-like distribution in which the center of the passage increases as the center approaches the end. For this reason, in the heating device of the present embodiment, if a large amount of intake air flows to the central portion of the heat radiating portion, in other words, to the inner heat radiating block 2, the inner heat radiating block 2 efficiently radiates heat. 1 can improve the heat generation efficiency. Further, since the plate-shaped PTC element 1 and the heat radiating block 2 were accommodated in the case having a rectangular shape, the heat radiating block 2 could be arranged on substantially the entire side surface of the PTC element 1. Therefore, not only the contact area between the PTC element 1 and the heat radiation block 2 can be increased, but also the passage portion of the heat radiation block 2 can be increased. for that reason,
The heat of the radiator can be effectively transmitted to the medium to be heated flowing through the passage of the radiator block. Furthermore,
2 through the plate 2b.
1 to be sandwiched by the inner heat dissipation block 200
Was. Therefore, the heat that is easily trapped in the center of the heating device,
The heat can be made uniform in the direction parallel to the PTC element 1,
The heat generated by the PTC element 1 is efficiently transmitted to the heat dissipation block.
Can be Since the heat radiating portion is sandwiched between the support portion 4e of the housing 4 and the cover 3b, the heat radiating portion is
Can be prevented from jumping from the inside to the outside.
FIG. 6 shows intake preheating characteristics before engine cranking. In the conventional intake air heating device using a metal wire, a preheating time of about 14 seconds (powering time to the device before engine cranking) was required.
It can be seen that since the temperature rise characteristics of the TC element 1 are fast, a preheating time of 3 to 5 seconds is sufficient. At this time, the room temperature is -25 ° C. and the power supply voltage is 24 V. In order to shorten the preheating time, it is necessary to increase the current. In this embodiment, the current is increased to 150 A in consideration of the relay capacity and the like. Thus, the resistance of the PTC element 1 is adjusted. FIG. 7 is a characteristic diagram showing the thermal efficiency including the time of intake air heating (after heat) after engine cranking. Here, the thermal efficiency is represented by the ratio of the amount of heat used to raise the temperature of air to the actually consumed electric power. As shown in FIG. 7, the device of this embodiment is superior to the metal wire device in both the initial startup efficiency and the steady-state efficiency. This is because the use of the PTC element 1 is excellent in immediate heat property, and the element itself heats intake air at a relatively low temperature, so that heat loss is small. FIG. 8 shows a measurement bench used for measuring the thermal efficiency of the apparatus. An intake heating apparatus 10 is provided in an expansion section 20a of a hot air passage 20, and a position 40 cm downstream of the apparatus 10 is used for temperature measurement. Is a point. 21 is a blower for blowing air, 2
Reference numerals 2 and 23 denote manometers for pressure loss measurement and flow rate measurement, and 24 and 25 denote DC and AC power supplies for driving the apparatus and the blower. The present invention is not limited to the above-described embodiment, and various modifications are possible as follows. (1) Since the graphite filler layer 1a is used to improve thermal and electrical contact failure due to irregularities on the surface of the heat transfer plate 2b or the surface of the PTC element 1, only the bent portion of the heat transfer plate 2b, that is, the pressing surface is used. May be provided, or P
It may be provided on both the TC element 1 and the heat transfer plate 2b. (2) Instead of the graphite filler layer 1a, a sheet of a heat-resistant rubber material obtained by dispersing and compounding carbon or metal powder or fiber may be employed. (3) Instead of the meandering fins 2a of the heat radiation block 2, a honeycomb-shaped metal fin or a porous metal fin may be used. (4) Although the inner heat radiation blocks 2 are configured to be pressed in a row in combination with three rows, not only the pressure but also the soldering may be bonded between the pressing surfaces of the heat transfer plate 2b. Of course, it may be constituted by one integrated heat dissipation block. (5) Instead of the structure in which the heat radiation block 2 and the PTC element 1 are pressed by the spring 5, the heat radiation block 2 and the PTC element 1 may be fixed and pressed by a method such as screwing to the case 3. (6) The louver 2'a provided on the radiation fin 2a may be omitted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing one embodiment of the present invention. FIG. 2 is a sectional view taken along line AA of FIG. FIG. 3 is a sectional view taken along line BB of FIG. 1; FIG. 4 is a partially enlarged view showing a heat radiation block of FIG. 1; FIG. 5 is a schematic diagram illustrating an example of a mounting location of a heating device. FIG. 6 is a characteristic diagram showing intake air heating characteristics of the heating device. FIG. 7 is a characteristic diagram showing intake air heating characteristics of the heating device. FIG. 8 is a schematic diagram showing a configuration of a measurement bench. [Description of Signs] 1 PTC element 2 Heat dissipation block 2a Heat dissipation fin 2b Heat transfer plate

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Makoto Hori               1-1-1 Showa-cho, Kariya-shi, Aichi Japan               Denso Co., Ltd.                (56) References Shokai Sho 57-126194 (JP, U)                 Actually open 1979-104447 (JP, U)

Claims (1)

(57) [Claims] (1) A plurality of heating elements which generate heat when energized, have a positive temperature resistance coefficient, and have a plate-like shape in which one side face is arranged to face each other; Between the heating elements facing each other and bent in a meandering shape
Radiation fins formed and bent ends on both sides of the radiation fins
Medium to be heated, comprising a heat transfer plate joined to
A plurality of passage portions for passing the
A plurality of first heat-dissipating blocks formed therebetween, and a pair of the plurality of heat-generating elements together with the first heat-dissipating blocks;
Heat radiation that is arranged on almost the entire area between the opposite sides and bent in a meandering shape
Fins and the heat transfer plate of the first heat dissipation block
And joined to the bent ends on both sides of the radiation fin.
And a heat transfer plate that passes through the medium to be heated.
A plurality of passage portions are formed between the meandering portions of the radiation fins.
The second radiating block sandwiched by the first radiating block
An inner heat dissipating block, an outer heat dissipating block disposed on substantially the entire surface on the other side opposite to the one side of the plurality of heating elements, and having a plurality of passages for passing a medium to be heated; And a rectangular shape accommodating the heating element, the first and second inner heat radiating blocks, and the outer heat radiating block such that the passage portions of the second inner heat radiating block and the outer heat radiating block are opened in a rectangular shape. And a total opening area of the passage portion opened by the case of the first and second inner heat dissipation blocks, and a total opening area of the passage portion opened by the case of the outer heat dissipation block. A heating device characterized by being set to be larger than the total opening area. (2) The bending widths of the radiating fins of the first and second inner heat radiating blocks and the outer heat radiating block are substantially the same, and as a result, the cumulative bending of the heat radiating fins of the first and second inner heat radiating blocks. The heating device according to claim 1, wherein the width is set to be dimensionally larger than the bending width of the radiation fin of the outer heat radiation block. (3) The bending width of the heat radiation fins of the first and second inner heat radiation blocks is set to be at least twice as large as the bending width of the heat radiation fins of the outer heat radiation block. 3. The heating device according to claim 2.