JP2013007355A - Heater unit with ptc heater and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PTC heater which minimizes breakage of a PTC heater at a heater unit assembly, and is excellent in mass productivity, and which is configured to reduce the occurrence of conduction failure.SOLUTION: A heater unit (1) consists of a pair of electrode and radiator plates (11, 15), substantially disc shaped PTC heaters (21, 22, 23, 24) sandwitched between the pair of electrode and radiator plates and brought into contact with inside surfaces of the pair of electrode and radiator plates, a rubber packing body (30) formed so as to surround a peripheral edge side part of a substantially disc shaped PTC heater and a rubber elastic body (40) filled in the clearance of at least a peripheral edge part of a pair of electrode and radiator plates. The whole unit is integrally constituted by the rubber elastic body. A pair of electrode and radiator plates are formed of a first conductive metal plate (11) and a second conductive metal plate (15). The rubber packing body is constituted so as to have a cross-sectional T shape or Y shape having a projection ring vertically in the thickness direction of the outer peripheral end thereof.

Description

  The present invention relates to an electric heater built in an LPG heating device in an LPG supply system that heats and vaporizes liquid LPG (liquefied petroleum gas) and sends it to an intake pipe in a state adjusted to a predetermined pressure and supplies it to an engine. The heater unit which has the PTC heater which comprises the principal part of this, and its manufacturing method.

  The use of LPG as a fuel for spark ignition engines is widely known, and vaporized gas decompressed to about atmospheric pressure using a vaporizer (regulator) and a mixer is sucked into an intake pipe and supplied to the engine. The method is conventionally performed. Further, as described in, for example, Japanese Patent Laid-Open No. 6-17709, a method of adjusting LPG to vapor gas having a predetermined positive pressure and injecting the gas into an intake pipe is widely known.

  As a means for heating and evaporating such liquid LPG, a heat exchanger using engine cooling water is built in the regulator or disposed on the inlet side thereof, and the LPG is heated using the heat of the engine cooling water. -Vaporization means are generally well known and used.

  However, the heating and vaporizing means using engine cooling water has a disadvantage that the liquid LPG cannot be sufficiently vaporized because the cooling water is at a low temperature when cold.

  In view of this, for example, Japanese Patent Laid-Open No. 5-223014 and Japanese Patent Laid-Open No. 11-324813 relate to a vaporizer configuration that vaporizes LPG and depressurizes it to about atmospheric pressure, in addition to using the heat of engine cooling water. Furthermore, a technique is disclosed in which an electric heater having a PTC heater is disposed in the LPG path so that LPG can be vaporized even when the cooling water is at a low temperature.

  For example, Japanese Patent Laid-Open No. 2007-309150 discloses a known configuration of a heater unit having a PTC heater which is a structural unit of an electric heater, and the specific configuration is an exploded perspective view of FIG. As shown in the figure. According to this, the heater unit 31 </ b> A includes two PTC heaters 320, a rubber seal body 36, electrode and heat dissipation plates 314 and 315, a PTC heater pressing spring body, and a unit frame 37. The PTC heater 320 is a plate-like body having a pair of flat surfaces and a peripheral side surface, and the rubber seal body 36 has two holes that can accommodate the PTC heater 320 in close contact with the peripheral side surface. Yes. Then, an assembly with the PTC heater 320 mounted in the two holes of the rubber seal body 36 is assembled so as to be sandwiched between the electrode and heat dissipation plates 314 and 315, and then the outer peripheral unit frame body 37 after the assembly. Are fitted and fixed together. Note that the contact between the PTC heater 320 and the electrode / heat radiating plates 314 and 315 is ensured by the PTC heater pressing spring body disposed on the inner surface of the electrode / heat radiating plate 315 on one side.

  The heater unit having a PTC heater having such a known configuration is (1) easy to disassemble and assemble, so that it is possible to replace a single part, and (2) the resistance value can be maintained by the pressing spring body. (3) There are advantages such as little damage to the PTC heater.

JP 2007-309150 A Japanese Patent Laid-Open No. 5-223014 Japanese Patent Laid-Open No. 11-324813 JP-A-6-17709

  By the way, the PCT heater used in the PTC heater unit is composed of a thin plate-like sintered body and has a property that is particularly fragile to local stress. In the case of mass production, controlling the pressing load on the PTC heater cannot be a sufficient countermeasure against damage.

  Moreover, since the rubber elastic body which comprises the periphery of a unit is heated by electricity supply and it produces thermal expansion, depending on a use condition, it may cause the poor contact between a PTC heater and an electrode.

  Further, when assembling the heater unit, if a part of the rubber member surrounding the PTC heater rides on the PTC heater, the continuity may deteriorate and lead to poor continuity. It is necessary and there is a problem in productivity.

  In order to solve such problems, the present invention has been devised. The purpose of the present invention is to minimize the damage of the PTC heater when assembling the heater unit, to be excellent in mass productivity, and to generate poor conduction. It is an object of the present invention to provide a heater unit having a PTC heater that can be reduced and a method for manufacturing the same.

  In order to solve such a problem, the present invention provides a heater having a PTC heater built in an LPG heating device of an LPG supply system that heats and vaporizes liquid LPG and adjusts the liquid LPG to a predetermined pressure and sends it to an intake passage of the engine. A heater unit comprising a pair of electrodes and a heat sink, a substantially disc-shaped PTC heater sandwiched between the pair of electrodes and a heat sink and contacting the inner surface of the pair of electrodes and a heat sink; A rubber packing body formed so as to surround a peripheral side surface portion of the substantially disc-shaped PTC heater, and a rubber elastic body filled in a gap between at least the peripheral edge portions of the pair of electrodes and the heat radiating plate, The whole unit is constituted by a rubber elastic body, and the pair of electrode / heat radiating plates includes a first conductive metal plate and a second conductive metal plate, and the rubber Kkingu body is configured as form a T-shaped cross section or Y-shaped with a protrusion ring up and down in the thickness direction of the outer peripheral end.

  Moreover, as a preferable aspect of the heater unit of the present invention, the protrusion ring for forming the T-shaped or Y-shaped cross section of the rubber packing body acts to relieve the repulsive force against the pressing force in the thickness direction of the rubber packing body. Further, the rubber elastic body is formed so as to exert an effect of preventing the rubber elastic body from riding on the plane of the PTC heater.

  Moreover, as a preferable aspect of the heater unit of the present invention, the rubber packing body is configured to have a durometer type A hardness of 55 to 80 degrees.

  As a preferred embodiment of the heater unit of the present invention, the thickness of the rubber packing body on the side in contact with the PTC heater is 0.5 to 0.8 mm, and the protrusion on the side of the rubber packing body in contact with the rubber elastic body The thickness of the outer peripheral end provided with the ring is configured to be 1.5 to 1.8 mm.

  As a preferred embodiment of the heater unit of the present invention, the rubber elastic body is configured to be at least one selected from the group consisting of fluorine rubber, urethane rubber, epichlorohydrin rubber, HNBR, and EPDM.

  As a preferred embodiment of the heater unit of the present invention, the rubber elastic body is fluororubber, a polyol compound is used as a vulcanizing agent of the rubber, and calcium hydroxide and magnesium oxide are contained as an acid acceptor. In addition, 5 to 10 parts by weight of calcium oxide is blended as a desiccant for capturing moisture generated by the polyol cross-linking reaction of fluororubber.

  Moreover, as a preferable aspect of the heater unit of the present invention, the material of the first conductive metal plate and the second conductive metal plate is configured to be copper or phosphor bronze.

Further, as a preferred embodiment of the heater unit of the present invention, the height of the PTC heater is H ₁ , the height of the rubber packing body in a crushed state is H ₂ , and the inner circumference of the rubber elastic body close to the rubber packing body When the height of the part is H ₃ , the configuration is such that H ₃ > H ₂ > H ₁ .

As a preferred embodiment of the heater unit of the present invention, the height of the PTC heater is H ₁ , and the height of the cross-sectional T-shape or Y-shape of the rubber packing body in the initial state before being crushed is H _4. , H ₄ > H ₁ .

  Moreover, as a preferable aspect of the heater unit of the present invention, both the flat surfaces of the PTC heater are configured such that an electrode film is formed except for a peripheral portion thereof.

  Moreover, as a preferable aspect of the heater unit of the present invention, the number of the PTC heaters arranged is four or two.

  Moreover, as a preferable aspect of the heater unit of the present invention, the outer surface of the electrode / heat radiating plate is configured to be coated with a fluororesin.

  Moreover, as a preferable aspect of the heater unit of the present invention, a silane coupling agent as a primer is interposed between the inner surface of the electrode / heat radiating plate and the rubber elastic body.

  As a preferred embodiment of the heater unit of the present invention, four PTC heaters are used, and the PTC heaters are arranged at intervals so as to form a square shape.

  The method for manufacturing a heater unit of the present invention includes a step of preparing a first conductive metal plate and a step of preparing a second conductive metal plate, wherein the second conductive metal plate is an assembly member. In the state of the part, a warped part is formed in advance, and the warped part has a center line of the second conductive metal plate as a base line and extends from the base line to both side ends. A step of preparing a second conductive metal plate formed symmetrically about the base line, and after mounting the first conductive metal plate in the cavity of the lower mold, A step of preforming a rubber elastic body so as to leave a disk-shaped PTC heater and a mounting hole for the rubber packing body on the first conductive metal plate, After removing the mold, the mounting hole has a substantially disc-shaped PT. A step of attaching the heater and the rubber packing body, and a rubber elastic body including the attached PTC heater and the rubber packing body are covered with a second conductive metal plate which is the other electrode and heat radiating plate. A process of attaching the second conductive metal plate, a step of attaching the upper mold for vulcanization for pressurizing the peripheral edge of the second conductive metal plate, and heating the mold to form a rubber elastic body The main vulcanization step is a main vulcanization step and the cooling step is performed to take out the heater unit after the main vulcanization from the mold and cool the rubber elastic body.

  Further, as a preferred embodiment of the heater unit manufacturing method of the present invention, the mold is evacuated after the step of attaching the upper mold for main vulcanization and before the step of main vulcanization. The vacuuming step for removing the air remaining in the heater unit is provided.

  As a preferred embodiment of the heater unit manufacturing method of the present invention, the upper mold at the time of the vulcanization has a compressive stress from the upper mold via the second conductive metal plate, In addition, it is configured to have a cavity configuration that is added to the rubber elastic body.

  The heater unit combination of the present invention comprises at least a pair of the heater units, and the second conductive metal plates of the pair of heater units are arranged to face each other via a compression spring, and are interposed. The outer periphery of the pair of heater units is fixed by the housing while maintaining the state in which the second conductive metal plate is pressed inside the heater unit by the biasing force of the compression spring. .

  The heater unit having the PTC heater of the present invention includes a pair of electrodes / heatsinks, a substantially disk-shaped PTC heater sandwiched between the pair of electrodes / heatsinks, and in contact with the inner surfaces of the pair of electrodes / heatsinks; A rubber packing body formed so as to surround a peripheral side surface portion of a disk-shaped PTC heater, and a rubber elastic body filled in a gap between at least the peripheral edge portions of the pair of electrodes and heat radiating plates. The entire unit is configured as an integral body by an elastic body, and the pair of electrodes and heat dissipation plates are configured to include a first conductive metal plate and a second conductive metal plate, and the rubber packing body is The cross-sectional T-shape or Y-shape with protrusion rings at the top and bottom in the thickness direction of the outer peripheral edge makes the PTC heater extremely small in damage, excellent in mass productivity, and poor conduction. Can be reduced in That.

FIG. 1 is a schematic exploded perspective view for easily explaining the configuration of the PTC heater unit. FIG. 2 is a drawing depicting an end view taken along the line β-β in FIG. 1. FIG. 3 is a plan view (only the PTC heater is depicted) schematically showing a contact state between the second conductive metal plate and the substantially disc-shaped PTC heater. FIGS. 4A to 4D are plan views for explaining the assembly method of the PTC heater unit of the present invention over time. 5 (a) to 5 (c) are cross-sectional views for explaining the main part of the manufacturing method of the PTC heater unit of the present invention over time. 6A is a cross-sectional view seen from the same direction as the end face of the arrow BB in FIG. 4D, and FIG. 6B reverses the LPG that has entered the heater unit as the internal pressure increases. It is sectional drawing which showed notionally the state diffused outside via a stop valve. In these drawings, the case where the second conductive metal plate finally becomes a flat plate is shown. FIG. 7 is a cross-sectional view illustrating a heater unit combination including a pair of heater units, as viewed from the same direction as the end face taken along the line B-B in FIG. FIG. 8 is a plan view schematically showing a contact state between the second conductive metal plate and the substantially disc-shaped PTC heater in the second embodiment (only the PTC heater is depicted). FIGS. 9A to 9C are cross-sectional views for explaining the main part of the manufacturing method of the PTC heater unit of the present invention in the second embodiment over time. FIG. 10 is a schematic diagram illustrating an example of an LPG supply system.

Hereinafter, the best mode for carrying out the present invention will be described in detail.
The heater unit of the present invention is built in an LPG heating device that constitutes a part of an LPG supply system that heats and vaporizes the liquid LPG and adjusts the liquid LPG to a predetermined pressure and sends it to the intake passage of the engine.

An example of the LPG supply system will be described with reference to FIG.
In the LPG supply system shown in FIG. 10, the LPG stored in the cylinder 101 in a liquid state passes through the liquid LPG flow path 91 and the gas LPG flow path 92 and is a gas injection valve installed in the intake passage 114 of the engine 104. 105. In this path, a shut-off valve 102, hot water heating means 310 and heating vaporization means 320 as the LPG heating device 300 are provided.
As shown, the heating and vaporizing means 320 is provided with an electric heating device 321 and a pressure regulator 322 (regulator).

  The illustrated LPG supply system opens and closes the closing valve 102 with an electronically controlled device 110, and controls energization from the battery 115 to the electric heating device 321 via a relay 112. A main fuse 116 is provided between the battery 115 and the relay 112.

  The LPG stored in a liquid state in the cylinder 101 passes through the liquid LPG flow path 91 (via the shut-off valve 102), enters the hot water heating device 310, and is supplied from the cooling water jacket 104a provided in the engine 104 to the cooling water feeder. The engine cooling water introduced via 108 is heated.

  However, when the engine 104 is cold, the temperature of the engine cooling water is low and the liquid LPG is not sufficiently heated, so that it cannot be sent into the gas LPG flow path 92 in a gas state.

  In this way, when the heating is insufficient only with the heat of the engine cooling water, the electronic control device 110 determines and energizes the subsequent electric heating device 321, and the LPG is operated by the electric heater 321 a disposed inside. Is supposed to heat.

  The structural unit of the electric heater 321a is composed of a heater unit having the PTC heater of the present invention (hereinafter also simply referred to as “PTC heater unit”). Hereinafter, the configuration of the PTC heater unit will be described.

Description of Configuration of PTC Heater Unit The PTC heater unit of the present invention is used by being incorporated in an LPG heating device of an LPG supply system that heats and vaporizes liquid LPG and adjusts the liquid LPG to a predetermined pressure and sends it to an intake passage of the engine.

  The drawings shown in FIG. 1 to FIG. 7 show a preferred embodiment in the case where four PTC heaters are arranged so as to form a quadrangular shape (a configuration in which the PTC heaters are arranged at square corners). In the drawings shown in FIGS. 1 to 7, for convenience of explanation, the horizontal (width) direction is displayed as the X-axis direction, the vertical (height) direction is displayed as the Y-axis direction, and the thickness direction is displayed as the Z-axis direction.

  As shown in the exploded perspective view of FIG. 1, the PTC heater unit 1 of the present invention includes a first conductive metal plate 11, a second conductive metal plate 15, which are a pair of electrodes and a heat radiating plate, and these Four substantially disc-shaped PTC heaters 21 and 22 that are sandwiched between the first and second conductive metal plates 11 and 15 and are in contact with the inner surfaces 11a and 15a of the pair of conductive metal plates 11 and 15. , 23, 24, a rubber packing body 30 formed so as to individually surround the peripheral side surfaces of the substantially disc-shaped PTC heaters 21, 22, 23, 24, and a pair of conductive metal plates 11, 15 And a rubber elastic body 40 filled in the gap.

  The rubber elastic body 40 has a so-called joining function and works so as to integrate the entire unit.

  Regarding the form of the rubber elastic body 40, the rubber elastic body 40 is formed by performing a preform using a preliminary mold and then performing a main vulcanization using the main mold. The shape shown in 1 is not necessarily formed as a member. Moreover, since the exploded perspective view is forcibly raised from the shape of the PTC heater unit after this vulcanization, it should be recognized as a schematic view only.

[ Description of PTC heaters 21, 22, 23, 24 ]
The PTC heater is a thermistor having a positive temperature characteristic (Positive Temperature Coefficient), and has a characteristic that an electric resistance value increases as the temperature rises. As the electrical resistance value increases, microscopic expansion occurs, thus separating the conductive material, making it difficult for current to flow and creating a system that reduces power consumption.

  Regarding the number of PTC heaters used, the case of using four is illustrated as a preferred example, but the use of two may be used and there is no particular limitation. The substantially disk-shaped form means a circle, an ellipse, a polygon with rounded corners, and the like in the planar form. However, from the viewpoint of evenly distributing the distortion of the PTC heater and preventing breakage, it is preferable to form a circular shape (a disk shape as a whole) in a planar form as in the embodiment. From the surface of the rubber packing body to be described later, it is preferable to form a circular shape in the planar form.

  Further, the peripheral flat portion of the substantially disc-shaped PTC heater (in the peripheral area of 5 to 15% R when the radius is R) is slightly smaller than the central main portion of the PTC heater (1 to 1). It is desirable to form it thinly (5% reduction). This is to ensure electrical connection between the pair of sandwiched electrode / heat radiation plates 11 and 15 and the PTC heater. Such a form can be easily realized, for example, by applying an electrode material paste such as Ag to both surfaces of the PTC heater except for the peripheral portion to form an electrode film.

  Note that the PTC heater has a high hardness as a material characteristic, and is vulnerable to impact and tends to break fragilely. In particular, it has the property of being relatively easily damaged by local stress.

  The thickness of the PTC heater is, for example, about 1.0 to 1.4 mm.

[ Description of Rubber Packing Body 30 ]
In the preferred example shown in FIG. 1, the rubber packing body 30 is formed as an integral rubber molding having mounting holes 31, 32, 33, 34 for mounting four substantially disc-shaped PTC heaters. The rubber packing body 30 is an already vulcanized rubber body and exists as a part. An opening hole 37 may be formed in the approximate center of the rubber packing body 30. Thus, the opening hole 37 provided as needed can be formed in order to install an umbrella-shaped check valve 50 to be described later and to leave a peripheral portion of the check valve vent hole. In addition, the size of the opening hole 37 may be made larger than the size shown in the drawing, and the central part to which the integral rubber molding is connected may be partially divided.

  Instead of the rubber packing body 30 made of an integral rubber molding as shown in FIG. 1, four separate ring-shaped rubber packing bodies having mounting holes 31, 32, 33, and 34 are prepared and used. It is also possible. However, in the case of a unit type including four PTC heaters as in the present embodiment, it is desirable to use an integral rubber molded product as shown in FIG. 1 in consideration of convenience in assembly, convenience of parts management, and the like.

  As shown in a partially enlarged sectional view (α-α arrow end surface) drawn and drawn in the lower part of the drawing of FIG. It is desirable to have a T-shaped cross section with 35a and 35b. The cross-sectional T shape may be a cross-sectional Y shape. When the upper and lower ends of the projection rings 35a and 35b are slightly tilted toward the outer peripheral side, a Y-shape is formed.

The projecting rings 35a and 35b for forming such a T-shaped or Y-shaped cross section can reduce the repulsive force against the pressing force in the thickness direction of the rubber packing body 30 (the shock can be reduced, the impact The rubber elastic body 40 is prevented from riding on the flat surfaces of the PTC heaters 21 to 24.
The thickness h1 (see FIG. 1) on the side (inner peripheral side) of the rubber packing body 30 in contact with the PTC heater is, for example, about 0.5 to 0.8 mm, more preferably about 0.6 to 0.7 mm. The thickness H _{4 of the} outer peripheral end provided with the projection rings 35a, 35b on the side (outer peripheral side) of the rubber packing body 30 in contact with the rubber elastic body 40 (see FIG. 1 (cross section of the rubber packing body in the initial state before being crushed) The height of the T-shape or Y-shape)) is about 1.5 to 1.8 mm.

Further, the T-shaped cross section or Y-shaped rubber packing body height in relation to the height H ₁ of the H ₄ and the PTC heater, H _4> relationship of an H ₁ that is maintained desired (FIG. 5 (See (a)).

  As described above, the rubber packing body 30 is an already vulcanized rubber part, and is preferably made of fluoro rubber. The durometer type A hardness is preferably about 55 to 80 degrees. The rubber packing body 30 having a hardness of less than 55 degrees is difficult to exist as a rubber when using fluoro rubber, and when the hardness exceeds 80 degrees, the repulsive force increases and the desired rubber deformation action of the present application is achieved. There is a risk that it will not be possible.

[ Description of Rubber Elastic Body 40 ]
As shown in FIG. 1, the rubber elastic body 40 includes a mounting hole 41 for mounting the rubber packing body 30 and the PTC heaters 21, 22, 23, 24 in the form after molding.

  Both flat surfaces of the four PTC heaters 21, 22, 23, 24 mounted in the mounting hole 41 are the inner surfaces of the pair of electrode and heat sinks 11, 15 that are integrally fixed to the rubber elastic body 40. Contact 11a, 15a in the form of the final product.

  The rubber elastic body 40 is composed of at least one selected from the group consisting of fluorine rubber, urethane rubber, epichlorohydrin rubber, HNBR, and EPDM. Further, it is preferable to use a binary fluororubber material so that preforming (preform) and main molding (main vulcanization) are possible.

In the compounding composition in the case of particularly suitably used fluororubber, a polyol vulcanizing agent as a vulcanizing agent; calcium hydroxide, magnesium oxide, magnesium / aluminum as an acid accepting agent (vulcanization accelerator) Hydroxide carbonate, etc .; it is desirable to contain calcium oxide (content of about 5 to 10 parts by weight) as a desiccant (bubble generation inhibitor). That is, as a preferred embodiment of the rubber elastic body 40, it is composed of fluororubber, a polyol-based compound is used as a vulcanizing agent for the rubber, calcium hydroxide and magnesium oxide are contained as acid acceptors, It is preferable that 5 to 10 parts by weight of calcium oxide is blended as a desiccant for capturing moisture generated by polyol polyol crosslinking reaction.
The molding method is preferably vacuum molding.

[ Description of a pair of conductive metal plates 11 and 15 ]
The first conductive metal plate 11 and the second conductive metal plate 15 which are a pair of electrodes and heat dissipation plates in the present invention are preferably made of copper or phosphor bronze. The first conductive metal plate 11 is a flat plate body, and the second conductive metal plate 15 is configured as a plate body having a warp form (a warped portion). In other words, the second conductive metal plate 15 has a warped portion formed in advance in the state of an assembly member (in the state of a component) before being incorporated in the PTC heater unit.

  As shown in FIG. 2 depicting the end view of the β-β arrow in FIG. 1, the warped portion preferably has a center line of the second conductive metal plate 15 as a base line M, and both sides from the base line M. Until the end of the base line M, the base line M is formed symmetrically. The warped part may be formed between the base line and the ends on both sides, but when four PTC heaters shown in FIG. In general, the distance L1 from the base line M is a flat area 15a, and it is preferable to form a warped portion 15b at L2 until the flat area 15a passes through the ends of both sides.

  The amount of warpage δ (see FIG. 2) due to the formation of the warped portion 15b can be determined by appropriately experimenting so that the manufacturing method described later can be reliably realized.

  The forms of the flat area 15a and the warped portion 15b shown in FIG. 2 continue in the same form toward the back area of the paper surface (toward the Y-axis direction). That is, a single plate is curved along the central axis.

  Although it will be easy to understand by referring to the description of the manufacturing method later, the shape of the warped portion 15b of the second conductive metal plate 15 may remain slightly after the heater unit according to the present invention is completed. It may be completely flat.

  When the warped portion remains slightly, as shown in the schematic diagram of the contact state between the second conductive metal plate and the substantially disk-shaped PTC heater shown in FIG. 3 (only the PTC heater is drawn), Each part of the peripheral portions 21b, 22b, 23b, 24b far from the base line M of the second conductive metal plate of the substantially disc-shaped PTC heater is not in contact with the second conductive metal plate. It is a floating part. Each part of 21a, 22a, 23a, and 24a (part shown with the oblique line) is a part which is in contact with the 2nd conductive metal plate.

  The thickness of the second conductive metal plate 15 is 0.2 to 0.4 mm, more preferably 0.3 mm.

  The first conductive metal plate 11 is a flat plate body, and the first conductive metal plate 11 is substantially in close contact with each of the PTC heaters 21, 22, 23, and 24 without floating. It is in.

  The thickness of the first conductive metal plate 11 is 0.6 to 0.8 mm, more preferably 0.7 mm.

  As described above, the outer surfaces (the surfaces opposite to the inner surfaces 11a and 15a) of the pair of conductive metal plates 11 and 15 as described above are preferably coated with a fluororesin. Such resin-lubricated coating is performed in order to prevent short circuit between heater units when conductive foreign matter is mixed, prevent contamination of the unit surface, and ensure insulation.

When the shape of the warped portion of the heater unit of the present invention described above remains substantially, the height of the PTC heater is H ₁ , the height of the collapsed rubber packing body is H ₂ , and the rubber elasticity When the height of the inner peripheral portion adjacent to the rubber packing body is H ₃ , the relationship of H ₃ > H ₂ > H ₁ is maintained (see FIG. 5C). Although it is necessary to consider the state before the heater unit is assembled, if the height of the rubber packing body in the initial state before being crushed is H ₄ (see FIG. 5A), H ₄ > H ₃ The relationship of> H ₂ > H ₁ is maintained.

  By maintaining such a relationship, a part of the peripheral portion of the substantially disc-shaped PTC heater is partially floating part G (see FIG. 5C) that is not in contact with the second conductive metal plate. ) Is formed. And since the heater unit which has such a structure does not apply an excessive press from the 2nd electroconductive metal plate 15 to a PTC heater, there is very few damages of a PTC heater, and also it is excellent in mass-productivity.

  As shown in FIG. 1, a check valve 50 can be installed on the first conductive metal plate 11 so that the internal fluid can be discharged to the outside of the unit when the pressure inside the unit rises. May be. The first conductive metal plate 11 has a vent hole 12 for venting the inside of the unit and a rod-shaped handle portion 55 of an umbrella type check valve 50 to be described later so that the check valve action can be exerted. You may form the handle | pattern part insertion hole 13 for making it insert compulsorily from the stop cove 56 side. For the installation state of the check valve 50, refer to FIG.

  Further, depending on the fixing method of the check valve 50, when the rod-shaped handle portion 55 of the umbrella type check valve 50 is inserted to the second conductive metal plate 15, FIG. As shown, the second conductive metal plate 15 is further provided with a rod-shaped handle 55 extending through the handle insertion hole 13 of the first conductive metal plate 11 and the second conductive metal plate 15. You may form the 2nd handle | groove part insertion hole 16 for making it penetrate to the exterior of. In such a configuration, the umbrella type check valve 50 can be easily locked and fixed.

[ Description of the check valve 50 installed on the outer surface of the first conductive metal plate ]
As shown in FIG. 1, a check valve 50 is formed on the outer surface of the first conductive metal plate 11 so that when the pressure inside the unit rises, the internal fluid can be discharged from the check valve to the outside of the unit. May be configured. In this case, the check valve 50 is composed of a rubber elastic body having an umbrella shape.

  That is, the check valve 50 made of a rubber elastic body having an umbrella shape is configured to support the umbrella portion 51 that can seal the vent hole 12 formed in the first conductive metal plate, and the umbrella portion 51. It has a rod-like handle 55 extending from the center and a stopper extension 56 formed at the tip thereof (a locking hump 56 for retaining). A rod-like handle portion 55 having a stopper extension 56 (a locking hump 56 for retaining) at the tip is formed on the first conductive metal plate 11 while being deformed to reduce the diameter of the stopper extension 56. The handle portion insertion hole 13 formed, the opening hole 37 formed substantially at the center of the rubber packing body 30, and the second handle portion insertion hole 16 formed in the second conductive metal plate 15 are sequentially inserted, and the first After the stopper extended portion 56 jumps out to the outside of the conductive metal plate 15, the stopper extended portion 56 (locking stop 56 for retaining) is fixed by rubber elasticity (see FIG. 6A). . That is, the stopper extension 56 is formed in a bump shape in advance in the umbrella part state.

  Although not shown in the present embodiment, the rod-shaped handle portion 55 provided with the stopper extension 56 (the retaining hook 56 for retaining) at the tip is deformed so as to reduce the diameter of the stopper extension 56. On the other hand, the stopper extended through rubber elasticity after being inserted into the handle insertion hole 13 formed in the first conductive metal plate 11 and popping out the stopper extension 56 inside the first conductive metal plate 11. You may make it fix with the expansion part 56 (locking cove 56 for retaining). That is, the stopper extension is formed so as to be in contact with the inner surface side 11 a of the first conductive metal plate 11. In this case, it is not necessary to form the second handle insertion hole 16 in the second conductive metal plate 15.

Description of Heater Unit Manufacturing Method Hereinafter, the heater unit of the present invention described above will be described with reference to FIGS. 1, 4A to 4D, 5A to 5C, and FIG. A method will be described.

  The heater unit manufacturing method of the present invention includes (1) a step of preparing a first conductive metal plate which is one electrode and heat dissipation plate, and (2) a second conductivity which is the other electrode and heat dissipation plate. A step of preparing a metal plate, (3) a step of preforming a rubber elastic body on the first conductive metal plate, and (4) a substantially disc-shaped PTC heater and rubber packing in the mounting hole. A body mounting step, (5) a deposition step of depositing a second conductive metal plate on a rubber elastic body including the mounted PTC heater and rubber packing body, and (6) main vulcanization. A step of mounting the upper mold for the machine, (7) a main vulcanization step of main vulcanizing the rubber elastic body, and (8) taking out the heater unit after the main vulcanization from the mold to cool the rubber elastic body. A cooling step in which the PTC heater and the second conductive metal plate are brought into contact with each other, and preferably as a preferable aspect And the check valve mounting step of placing a check valve can be pressurized (9) first electrically conductive metal plate, sequentially, and is configured to have.

Hereinafter, it demonstrates for every process.
<The process of preparing the 1st electroconductive metal plate which is one electrode and heat sink >
First conductive metal plate 11 (preferably composed of a copper plate) is prepared in advance. The first conductive metal plate 11 is composed of a flat plate.

<The process of preparing the 2nd electroconductive metal plate which is the other electrode and heat sink >
A second conductive metal plate 15 (preferably composed of a copper plate) is prepared in advance. As described above, the second conductive metal plate 15 is composed of a plate body in which a warped portion is formed in advance.

< Process of preforming rubber elastic body on first conductive metal plate >
As shown in FIG. 4A, the rubber elastic body 40 is preformed on the prepared first conductive metal plate 11.

  Specifically, after the first conductive metal plate 11 is mounted (inserted) in the cavity of the lower mold for transfer molding, the first conductive metal is attached in a state where the mold on the preform is attached. A plate-like PTC heater and a mounting hole 41 for the rubber packing body are left on the plate 11 (the core pin for forming the mounting hole 41 is arranged so as to contact the surface of the plate 11. The rubber elastic body 40 is preformed. At the bottom of the hole 41, the inner surface 11a of the first conductive metal plate 11 can be seen.

In the preforming, for example, the temperature of the preliminary mold is set to 110 ° C., and a binary FKM (fluorine) rubber is preformed. The pressure is, for example, about 15 tons (86 kgf / cm ² ), and the time is, for example, about 10 seconds.

  In addition, a primer such as a silane coupling agent is applied in advance to the area where the first conductive metal plate 11 is joined to the rubber elastic body 40 (excluding the portion where the PTC heater is in contact) in order to improve the adhesion. It is desirable to keep it.

<A process of mounting a substantially disc-shaped PTC heater and a rubber packing body in the mounting hole>
After removing the preform upper mold, the PTC heaters 21, 22, 23, and the rubber packing body 30 are mounted in the mounting hole 41 as shown in FIG.

  The PTC heaters 21, 22, 23, 24 and the rubber packing body 30 may be mounted by first mounting the rubber packing body 30 in the mounting hole 41 and then mounting each PTC heater. Alternatively, the PTC heater and the rubber packing body can be integrated into the mounting hole 41 in an integrated state.

< Deposition step of depositing the second conductive metal plate on the rubber elastic body >
As shown in FIG. 4C, the PTC heaters 21, 22, 23, 24 and the second PTC heaters 21, 22, 23, 24 and the second PTC heaters 21, 22, 23, 24 and the rubber elastic body 40 including the rubber packing body 30 are attached. A process of depositing the second conductive metal plate 15 is performed in which the second conductive metal plate 15 is covered with the conductive metal plate 15 kept in a non-contact state.

  Drawings following the AA arrow cross section of FIG. 4C are shown in FIG. 5A and FIG. That is, the state shown in FIG. 5A is a state where the second conductive metal plate 15 is about to be deposited from now, and the state shown in FIG. 5B is the second conductive metal. This is the state after the plate 15 is deposited. At this time, as shown in FIG. 5B, the specifications of each member are determined so that the PTC heaters 21, 22, 23, 24 and the second conductive metal plate 15 are kept out of contact with each other. ing.

  In addition, a primer such as a silane coupling agent is applied in advance to the area where the second conductive metal plate 15 is joined to the rubber elastic body 40 (excluding the portion where the PTC heater is in contact) in order to improve the adhesive strength. It is desirable to keep it.

< The step of mounting the upper mold for main vulcanization and the main vulcanization step of main vulcanizing the rubber elastic body >
In these steps, as a preferred embodiment, only the peripheral edge of the second conductive metal plate 15 is pressed so that the PTC heater and the second conductive metal plate are not pressed with a strong force. It is recommended that the upper mold is mounted. That is, it is desirable that the cavity form to be pressed by the upper mold for vulcanization is configured so that only the peripheral edge of the rubber elastic body 40 can be pressed as much as possible. In other words, the upper mold at the time of the main vulcanization is such that the compressive stress from the upper mold passes through the second conductive metal plate 15 and the PTC heater is not pressed so much, and the rubber elastic body 40 It can be said that it is desirable to have a cavity configuration that can be added to.

  Next, a main vulcanization step of heating the metal mold and vulcanizing the rubber elastic body 40 while maintaining the state where the PTC heaters 21, 22, 23, 24 and the second conductive metal plate 15 are not in contact with each other. Is implemented. As described above, the PTC heaters 21, 22, 23, 24 and the second conductive metal plate 15 are not in contact with each other at the high temperature when the main vulcanization is performed. In such a main vulcanization step, the distance between the held PTC heaters 21, 22, 23, 24 and the second conductive metal plate 15 (the closest part) is in the range of 0.05 to 0.15 mm. It is desirable that

  The conditions for the main vulcanization may be, for example, a vulcanization temperature of about 170 ° C. and a vulcanization time of about 10 minutes.

<Cooling step of taking out the main vulcanized heater unit from the mold and cooling the rubber elastic body>
The heater unit after the main vulcanization is taken out from the mold, the rubber elastic body 40 is cooled, and the PTC heaters 21, 22, 23, 24 and the second conductive metal are used by utilizing the shrinkage characteristics of the rubber elastic body 40. A cooling process for contacting the plate 15 is performed. Only in this cooling process, the PTC heaters 21, 22, 23, 24 and the second conductive metal plate 15 come into contact with each other, and the structure shown in FIG.

  In the series of manufacturing steps described above, after the step of attaching the upper mold for vulcanization and before the step of main vulcanization, the mold is evacuated and remains in the heater unit. It is desirable to provide a evacuation step for removing air. Thereby, for example, the outgas of the rubber elastic body can be removed and voids can be prevented.

<As a preferred embodiment, a check valve mounting step when a check valve is installed on the first conductive metal plate >
A check valve 50 made of a rubber elastic body having an umbrella shape is prepared. Such a check valve 50 extends from the center so as to support the umbrella portion 51 that can seal the vent hole 12 formed in the first conductive metal plate 11 as described above. It has a rod-shaped handle portion 55 (preferably having a taper shape that becomes thinner toward the tip) and a stopper extension 56 formed at the tip of the rod-like handle portion 55 (a locking cove 56 for retaining). The The lower surface side of the umbrella portion 51 (the surface on which the base portion of the handle portion 55 is present) is a flat surface, and the flat surface closes one end of the vent hole 12, and the vent hole 12 is in a normal state where the internal pressure is not increased. Is closed.

  A rod-like handle portion 55 having a stopper extension 56 (a locking hump 56 for retaining) at the tip is formed on the first conductive metal plate 11 while being deformed to reduce the diameter of the stopper extension 56. The handle portion insertion hole 13 formed, the opening hole 37 formed substantially at the center of the rubber packing body 30, and the second handle portion insertion hole 16 formed in the second conductive metal plate 15 are sequentially inserted, and the first After the stopper extended portion 56 jumps out to the outside of the conductive metal plate 15, the stopper extended portion 56 (locking protrusion 56 for retaining) is expanded by rubber elasticity. The state is shown in FIG.

  In FIG. 6 (b), when the pressure inside the unit rises, a part of the periphery of the check valve umbrella portion 51 rises and the internal fluid is released to the outside of the unit through the vent hole 12. The state is shown as a conceptual diagram.

  FIG. 7 shows a cross-sectional view of a heater unit combination including a pair of the above heater units. The cross-sectional position is a central position (corresponding to the BB cross section) similar to that shown in FIG.

  As shown in FIG. 7, the pair of heater units 1, 1 are arranged such that the second conductive metal plates 15, 15 constituting these units face each other. Then, compression springs 61 and 61 are interposed in the space where the second conductive metal plates 15 and 15 are opposed to each other. The urging force of the compression springs 61 and 61 causes the second conductivity. The outer periphery of the pair of heater units 1 and 1 is fixed by a housing 70 so that the state where the metal plate is pressed inside the heater unit can be maintained. The compression springs 61 and 61 are configured to be substantially integrated in a loosely fitted or fixed state by the reinforcing plate 65 so that the compression springs 61 and 61 can be installed in a stable state. It is desirable. As described above, the state in which the second conductive metal plate is pressed to the inside of the heater unit by the urging force of the compression springs 61 and 61 can be maintained. As a result, the PTC heater and the second conductive metal plate The contact state, and further, the contact state between the PTC heater and the first conductive metal plate can be favorably maintained. As a result, the amount of heat generated during energization can be increased and stabilized.

[ Description of Modifications of the Present Invention ]
As a modification of the first embodiment of the present invention described above, two PTC heaters are used, and the drawings relating to the second embodiment in which these PTC heaters are arranged at intervals in columns are shown in FIGS. It is shown in FIG.

  8 is a drawing corresponding to FIG. 3 of the first embodiment described above, and FIG. 9 is a drawing corresponding to FIG. 5 of the first embodiment described above. 8 to 9, members having the same reference numerals as those used in FIGS. 1 to 5 are members that exhibit the same action.

  In the second embodiment in which two PTC heaters are used and arranged at intervals in the column, a schematic diagram of the contact state between the second conductive metal plate and the substantially disc-shaped PTC heater shown in FIG. As shown in the figure, only the PTC heater is drawn), each part of the reference numerals 21a and 22a (the part drawn with diagonal lines) near the base line M of the second conductive metal plate of the substantially disc-shaped PTC heater is , A portion in contact with the second conductive metal plate. Each part of the peripheral portions 21b and 22b far from the base line M is a floating portion which is a portion not in contact with the second conductive metal plate.

  Also in the second embodiment, the main part of the basic manufacturing method is the same as that of the first embodiment as shown in FIGS.

  As an industrial applicability of the present invention, the present invention provides an LPG supply system that heats and vaporizes liquid LPG (liquefied petroleum gas), adjusts it to a predetermined pressure, sends it to the intake pipe, and supplies it to the engine. Available for related technologies.

DESCRIPTION OF SYMBOLS 1 ... Heater unit 11 ... 1st electroconductive metal plate which is an electrode and heat sink 15 ... 2nd electroconductive metal plate which is an electrode and heat sink 11a, 15a ... Inner surface of a pair of electrode and heat sink 21,22 , 23, 24 ... PTC heater 30 ... Rubber packing body 40 ... Rubber elastic body 41 ... Mounting hole for mounting the rubber packing body and PTC heater 50 ... Check valve 51 ... Umbrella portion 55 ... Handle portion 56 ... Stopper Expansion part 61 ... Compression spring 65 ... Reinforcement plate 70 ... Housing

Claims (18)

A heater unit having a PTC heater built in an LPG heating device of an LPG supply system that heats and vaporizes the liquid LPG and adjusts the liquid LPG to a predetermined pressure and sends it to an intake passage of the engine,
The heater unit is
A pair of electrodes and heat sink;
A substantially disc-shaped PTC heater that is sandwiched between a pair of electrodes and a heat sink and is in contact with an inner surface of the pair of electrodes and a heat sink;
A rubber packing body formed so as to surround the peripheral side surface portion of the substantially disc-shaped PTC heater;
A rubber elastic body filled in at least the gap between the peripheral edges of the pair of electrodes and heat dissipation plate,
The rubber elastic body constitutes the entire unit as an integral unit,
The pair of electrodes and heat radiating plates includes a first conductive metal plate and a second conductive metal plate,
The heater unit according to claim 1, wherein the rubber packing body has a T-shaped or Y-shaped cross section provided with protrusion rings on the upper and lower sides in the thickness direction of the outer peripheral end thereof.   The projecting ring for forming the T-shaped or Y-shaped cross section of the rubber packing body has a function of reducing the repulsive force against the pressing force in the thickness direction of the rubber packing body and the rubber elastic body runs on the plane of the PTC heater. The heater unit according to claim 1, wherein the heater unit is formed so as to exhibit an action to prevent.   The heater unit according to claim 1 or 2, wherein the rubber packing body has a durometer type A hardness of 55 to 80 degrees.   The thickness of the rubber packing body on the side in contact with the PTC heater is 0.5 to 0.8 mm, and the thickness of the outer peripheral end provided with the protruding ring on the side of the rubber packing body in contact with the rubber elastic body is 1. The heater unit according to any one of claims 1 to 3, wherein the heater unit is 5 to 1.8 mm.   The heater unit according to any one of claims 1 to 4, wherein the rubber elastic body is at least one selected from the group of fluorine rubber, urethane rubber, epichlorohydrin rubber, HNBR, and EPDM.   The rubber elastic body is a fluororubber, a polyol-based compound is used as a vulcanizing agent for the rubber, calcium hydroxide and magnesium oxide are contained as an acid acceptor, and is generated by a polyol cross-linking reaction of the fluororubber. The heater unit according to claim 5, wherein 5 to 10 parts by weight of calcium oxide is blended as a desiccant for capturing moisture.   The heater unit according to any one of claims 1 to 6, wherein a material of the first conductive metal plate and the second conductive metal plate is copper or phosphor bronze. When the height of the PTC heater is H ₁ , the height of the rubber packing body in the crushed state is H ₂ , and the height of the inner peripheral portion adjacent to the rubber packing body of the rubber elastic body is H ₃ , _3> H _2> heater unit according to any one of claims 1 to 7 is H _1. The PTC height H ₁ of the heater, if the height of the T-shaped cross section or Y-shaped rubber packing member before the initial state is collapsed and the H _4, claims 1 is H _4> H ₁ The heater unit according to claim 7.   The heater unit according to any one of claims 1 to 9, wherein an electrode film is formed on both flat surfaces of the PTC heater except for a peripheral portion thereof.   The heater unit according to any one of claims 1 to 10, wherein the number of the PTC heaters disposed is four or two.   The heater unit according to any one of claims 1 to 11, wherein an outer surface of the electrode / heat radiating plate is coated with a fluororesin.   The heater unit according to any one of claims 1 to 12, wherein a silane coupling agent as a primer is interposed between an inner side surface of the electrode / heat radiating plate and the rubber elastic body.   The heater unit according to any one of claims 1 to 13, wherein four PTC heaters are used, and the PTC heaters are arranged at intervals so as to form a square shape. A method for manufacturing a heater unit according to any one of claims 1 to 14,
The method
Preparing a first conductive metal plate;
A step of preparing a second conductive metal plate, wherein the second conductive metal plate is preliminarily formed with a warped portion in a state of a component as an assembly member; A step of preparing a second conductive metal plate formed symmetrically with respect to the base line between the base line and the ends on both sides, with the center line of the conductive metal plate as a base line;
After the first conductive metal plate is mounted in the cavity of the lower mold, the disk-shaped PTC is placed on the first conductive metal plate in a state where the upper mold is attached. A step of preforming a rubber elastic body so as to leave a mounting hole for the heater and the rubber packing body;
Attaching the substantially disc-shaped PTC heater and the rubber packing body to the mounting hole after removing the preform upper mold;
The process of depositing the second conductive metal plate, which covers the second elastic metal plate, which is the other electrode and heat dissipation plate, on the rubber elastic body including the mounted PTC heater and the rubber packing body. When,
Attaching the upper mold for vulcanization for pressurizing the periphery of the second conductive metal plate;
A main vulcanization process in which the mold is heated to vulcanize the rubber elastic body;
A cooling step of taking out the heater unit after the main vulcanization from the mold and cooling the rubber elastic body;
A method for manufacturing a heater unit, comprising:   After the step of attaching the upper mold for vulcanization, and before the step of vulcanization, a evacuation step of evacuating the mold and removing air remaining in the heater unit is performed. The manufacturing method of the heater unit of Claim 15 provided.   The upper mold at the time of this vulcanization has a cavity shape in which the compressive stress from the upper mold is applied to the rubber elastic body without being applied to the PTC heater via the second conductive metal plate. The method of manufacturing a heater unit according to claim 15 or 16, wherein the heater unit is configured. A heater unit combination comprising at least a pair of heater units according to any one of claims 1 to 14,
The second conductive metal plates of the pair of heater units are arranged to face each other via a compression spring, and the second conductive metal plate is placed inside the heater unit by the biasing force of the interposed compression spring. A heater unit combination, wherein the outer periphery of the pair of heater units is fixed by a housing while maintaining the state pressed by the housing.

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