JP6052433B2 - Heat sealer - Google Patents

Description

  The present invention relates to a heat sealer used for heat welding of an object.

  As an apparatus for heat-welding an object using a thermoplastic resin, Patent Document 1 uses a ribbon-shaped heater in a thin strip shape, and a large current is passed in a short time to heat the heater instantaneously. A so-called impulse heat sealer that is melted, disconnected, cooled and solidified is disclosed.

  In this heat sealer, a heater is layered on the seal head (heat radiating stand), and a seal top, which is a ceramic thin plate that comes into contact with the object, is further stacked on the seal head, and these are bonded with an adhesive and fixed to the seal head side. doing.

International Publication No. 2010/116567

  However, in the above-mentioned conventional one, a thin plate of a thermoelectric insulator such as a cercon tape is interposed between the metal seal head (heat radiation table) and the heater wire. Heat sealers used in batteries may have heater temperatures exceeding 200 degrees, and thermoelectric insulators such as cercon sheets deteriorate and deform over time, so the sealing surface in contact with the object to be welded is inclined. There is a possibility that the welding quality may be deteriorated.

  Also, if there is an elastic layer such as a cercon tape between the press devices, the elastic layer will bend even if pressure is increased due to variations in the way the elastic layer bends. Therefore, it is difficult to apply a sufficient pressure, or it takes a long time, so that it cannot be crushed to a predetermined seal thickness within the time, and there is a possibility that the quality is deteriorated.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a novel heat sealer that can maintain the welding quality for a long period of time without causing the seal surface to be inclined even when used over time. It is said.

  The heat sealer according to the present invention includes a seal head, a seal top supported on the seal head and having a press surface for pressing an object on the upper surface, and between the upper surface of the seal head and the lower surface of the seal top. And a thin plate heater that heats the seal top by heating by energizing current, and welding is performed by melting the object by pressing with the heated seal top.

  Both the seal head and the seal top are made of metal. An accommodating portion for accommodating the heater is formed on the opposing surface of the seal head and the seal top. The seal head and the seal top are connected by metal.

  Here, the connection by metal includes not only fastening by bolts but also welding metal parts, and may also be ones having a metal holding member interposed.

  According to the present invention, since the seal head and the seal top are rigidly connected to each other by metal, the seal surface is not inclined even when used over time, and the welding quality can be maintained for a long time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a schematic structure of a laminate type lithium ion secondary battery to be manufactured by a heat sealer according to a first embodiment of the present invention. FIG. 3 is an exploded perspective view of the laminate type lithium ion secondary battery. Sectional drawing which follows the AA line of FIG. 1 which shows the heat sealer of a present Example. Sectional drawing which follows the AA line of FIG. 1 which shows the said heat sealer. Sectional drawing which shows the said heat sealer. Sectional drawing which expands and shows the principal part of the said heat sealer. The perspective view which shows the holding structure of the seal top of the said heat sealer. Explanatory drawing which shows the holding structure of the seal top of the said heat sealer. The perspective view which shows the holding structure of the seal top of the heat sealer of a comparative example. Sectional corresponding drawing which follows the BB line of FIG. 1 which shows the heat sealer which concerns on 2nd Example of this invention. Sectional corresponding drawing which follows the AA line of FIG. 1 which similarly shows the heat sealer which concerns on 2nd Example. Sectional drawing which shows the heat sealer which concerns on 3rd Example of this invention. Sectional drawing which shows the heat sealer which concerns on 4th Example of this invention.

  Hereinafter, the present invention will be described with reference to illustrated embodiments. First, referring to FIG. 1 and FIG. 2, as an object to be manufactured by the heat sealer 10 (10A) according to this embodiment, a lithium ion secondary battery 1 (hereinafter simply referred to as a laminate type secondary battery). The schematic structure of “battery”) is shown. The battery 1 is used as a unit cell or a single battery of a lithium ion battery for an electric vehicle, for example.

  As shown in FIGS. 1 and 2, the battery 1 has a lead terminal (positive electrode terminal portion) 2 as a positive electrode terminal and a lead terminal (negative electrode terminal) 3 as a negative electrode terminal leading out to the outside. In this state, it is housed and sealed by a rectangular laminate film exterior body 4 composed of two upper and lower laminate films 4a and 4b as exterior films. In the laminate film outer package 4, a laminate 5 formed by laminating a plurality of sets of positive and negative electrodes as electrodes that are power generation elements and a separator interposed therebetween is accommodated together with an electrolytic solution. The laminate film outer package 4 is hermetically sealed or sealed by the four sides of the heat-sealed portion 6 that is the peripheral portion of the laminate film outer package 4.

  That is, in the battery 1 shown in FIG. 1 and FIG. 2, battery elements including a positive electrode and a negative electrode that are electrodes, a separator, and an electrolytic solution are surrounded by a laminate film outer package 4, and each positive and negative current collector The lead terminals 2 and 3 electrically connected to each other are led out to the outside of the laminate film exterior body 4, and the peripheral portion of the laminate film exterior body 4 is sealed or sealed in a rectangular bag shape by heat welding. By performing the treatment, the airtightness as the battery 1 is secured. As the two upper and lower laminate films 4a and 4b forming the laminate film outer package 4, for example, a composite structure in which both front and back surfaces of an aluminum foil are covered with a heat-welding resin film is used.

  The positive lead terminal 2 and the negative lead terminal 3 are both led out from one common side of the rectangular laminated film outer package 4. Both lead terminals 2 and 3 may be referred to as electrode tabs. The lead terminal 2 on the positive electrode side is made of, for example, aluminum, and the lead terminal 3 on the negative electrode side is made of, for example, copper. Both lead terminals 2 and 3 are preliminarily subjected to a predetermined surface treatment and are covered with a heat-weldable and insulating resin layer (not shown). The lead terminals 2 and 3 are not limited to this configuration. For example, the lead terminal 2 and the lead terminal 3 may be led out from a pair of opposing sides.

  The four sides of the rectangular laminate film outer package 4 are welded in several steps, for example, by the heat sealers 10 and 10A according to the present embodiment. FIG. 3 shows an enlarged cross-sectional view taken along the line AA in FIG. 1 and FIG. 4 shows an enlarged cross-sectional view taken along the line BB at the time of heat welding.

  As shown in FIGS. 3 and 4, the overlapping portions of the plurality of positive electrodes 8 forming a part of the laminate 5 of FIG. 2 are overlapped with each other, and the overlapping portion 8 a is connected to the positive lead terminal. 2 is connected by welding. This structure is basically the same for the relationship between the negative electrode and the lead terminal 3 on the negative electrode side, and these structures are not shown in FIG.

  As shown in FIG. 4, the heat sealers 10 and 10 </ b> A include a lower heat sealer 10 and an upper heat sealer 10 </ b> A that are opposed to each other so as to be close to and away from each other. In both the heat sealers 10 and 10A, the portion responsible for heat welding extends in the longitudinal direction of the heat welding portion 6 (see FIG. 1) of the laminate film exterior body 4 in a plan view, and the width dimension of the laminate film exterior body 4 The dimension is set to be slightly larger than the width dimension of the heat welding part 6.

  Then, the upper and lower heat sealers 10 and 10A are moved close to each other while the upper and lower laminate films 4a and 4b to be the laminate film outer package 4 surrounding the laminate 5 shown in FIG. Then, the heat welding part 6 is heat-welded by pressurizing and restraining the two upper and lower laminate films 4 a and 4 b from above and below, and the laminate film exterior body 4 is finished.

  In addition, the lead terminal 2 on the positive electrode side is interposed between the portion of the laminate film outer package 4 where the upper and lower laminate films 4a and 4b are directly heat-welded and the upper and lower laminate films 4a and 4b. The thicknesses of the laminated films 4a and 4b and the lead terminal 2 on the positive electrode side are inevitably different from each other, so that a step is inevitable at the boundary between them. Although not shown in order to correspond to this level | step difference, the press surface 12a used as the contact surface with laminate film 4a, 4b also has a predetermined level | step difference.

  At the time of heat welding, two upper and lower laminate films 4a and 4b to be the laminate film outer package 4 surrounding the laminate 5 in FIG. 2 with the upper and lower heat sealers 10 and 10A being separated from each other. Is supported by a support member (not shown), and the heat-welded portions 6 of these laminate films 4a and 4b are disposed and positioned between the upper and lower heat sealers 10 and 10A, and both are moved close to each other, so that two upper and lower laminates are laminated. The films 4a and 4b are pressed and restrained from above and below. And in this pressurization restraint state, each heater 13 is impulse-energized and heat-welded. It should be noted that while a conventional so-called hot plate type heater requires about 13 seconds to complete the welding, the impulse type heater 13 as described above completes the thermal welding in about 4 seconds. In addition, after energization is completed, cooling is performed while maintaining the pressurized state for a predetermined time.

  Next, the specific structure of the heat sealer will be described in detail using the lower heat sealer 10 shown in FIGS. The upper heat sealer 10 </ b> A has the same structure as the lower heat sealer 10, and is not described here.

  Here, in this specification, in order to explain the relative positional relationship between the seal head and the seal top, for the sake of convenience, it is assumed that the seal head is disposed below and the seal top is disposed above. It does not mean the vertical position of the seal head or the seal top. For example, in the case of the upper heat sealer 10A, the seal head 11 is arranged vertically upward and the seal top 12 is arranged vertically downward in the usage form.

  Each heat sealer 10 includes a seal head 11, a seal top 12 that is supported on the seal head 11, and has a press surface 12 a that presses the heat-welded portion 6 of the laminate film outer package 4 as an object on the upper surface, and a seal A thin plate-like heater 13 is provided between the upper surface of the head 11 and the lower surface of the seal top 12 and generates heat by energizing current to heat the seal top 12.

  The heater 13 is an impulse heater having a ribbon-like thin strip shape in which a heater wire such as iron chrome is uniformly incorporated in a cloth woven of heat-resistant glass fibers. 3 to 5, the heater 13 is depicted as having a certain thickness for the sake of clarity, but in actuality, the thickness is extremely thin with a thickness of 1 mm or less.

  The seal top 12 is made of a substantially rectangular parallelepiped as simple as possible in order to minimize the heat capacity and improve the thermal conductivity to the heat-welded portion 6 while ensuring the rigidity against pressure (press) at the time of heat-welding. The shape is a thin plate shape. The width dimension of the seal top 12 is set larger than the width dimension of the heater 13.

  The seal top 12 is formed of a metal material, and copper, aluminum alloy, stainless steel, or the like can be used as the material, but preferably has low thermal conductivity, in other words, high heat storage and thermal expansion. Carbon steel (S45C) or stainless steel (SUS) having a low rate, more preferably stainless steel having excellent rigidity is used.

  Chamfered portions 14 having a predetermined radius of curvature are formed on both edges of the top surface of the seal top 12 having the press surface 12a so as not to damage the surface of the laminate film exterior body 4 as an object. .

  The seal head 11 is made of a metal material like the seal top 12, and a metal material such as copper, aluminum alloy, stainless steel or the like can be used for the material, but preferably the thermal conductivity is low, in other words. Carbon steel (S45C) or stainless steel (SUS) having high heat storage and low thermal expansion coefficient is used. In this embodiment, since the seal head 11 is not required to be as rigid and strong as the seal top 12, relatively inexpensive carbon steel is used.

  A first protective layer 16 is formed on the surface of the seal top 12 by a coating process over the entire surface. In addition, a second protective layer 17 is formed on the seal head 11 by a coating process on the bottom surface and both side surfaces of a deep bottom portion 19 to be described later. That is, the entire surface including the upper and lower surfaces of the heater 13 is covered with the protective layers 16 and 17. In order to improve the positional accuracy of the seal top 12 with respect to the seal head 11, the second protective layer 17 is not provided on the bottom surface and both side surfaces of the shallow bottom portion 18 that accommodates and holds the seal top 12 by masking or the like. I have to.

  The material of these protective layers 16 and 17 is preferably a material having a low friction coefficient, and typically, a synthetic resin material having a friction coefficient of 0.05 to 0.15 such as a fluororesin is preferable. In this embodiment, PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether polymer) is used as a material for the protective layers 16 and 17.

  Further, the thickness of the first protective layer 16 of the first protective layer 16 and the second protective layer 17 is set to be relatively thin so that heat is efficiently transmitted to the seal top 12 as compared with the seal head 11. ing. As an example, the thickness of the first protective layer 16 is set to 30 μm, and the thickness of the second protective layer 17 is set to 50 μm.

  Furthermore, the hardness of the protective layers 16 and 17 is much softer than a metal having HB of 1 or less.

  On the upper surface side of the seal head 11, a shallow bottom portion 18 that houses and holds the seal top 12 and a deep bottom portion 19 that serves as a housing portion that houses and holds the heater 13 are recessed. That is, the deep bottom portion 19 of the channel shape that is further deeply recessed is recessed in two steps on the bottom surface of the shallow bottom portion 18 that is recessed in the channel shape. At the time of assembly, the seal head 11 is placed on the bottom surface of the shallow bottom portion 18 from above while the heater 13 is accommodated and disposed in the deep bottom portion 19. And the seal | sticker top 12 is pressed and fixed on the seal head 11 by the holding mechanism 23 (refer FIG. 6-8) mentioned later, and the heater 13 is between the seal head 11 and the seal top 12 in the deep bottom part 19. FIG. Retained.

  The height dimension H1 of the deep bottom portion 19 is a dimension (H2 + H3) obtained by adding the thickness H2 of the heater 13 and the thickness H3 of the second protective layer 17 provided on the bottom surface of the deep bottom portion 19 of the seal head 11. It is set almost the same. Therefore, as shown in FIGS. 5 and 6, the heater 13 is accommodated in the deep bottom portion 19 with substantially no gap in the vertical direction, and the upper and lower surfaces of the heater 13 are arranged on the first and second protective layers 16. , 17 (including a state of being opposed to each other through a slight gap). It should be noted that a thermal joint may be further applied to the surfaces of the protective layers 16 and 17 as necessary so as to more reliably fill the gap with the heater 13.

  The width dimension of the deep bottom portion 19 is set slightly larger than the width dimension of the heater 13. Therefore, on both sides of the heater 13, a slight gap 22 that allows and absorbs the expansion and contraction in the width direction of the heater 13 is secured between both sides of the deep bottom portion 19.

  The width of the seal top 12 is set to be larger than the deep bottom portion 19 and smaller than the shallow bottom portion 18. Therefore, the seal top 12 is placed on the bottom surface of the shallow bottom portion 18 without entering the deep bottom portion 19, and the lower surface of the seal top 12 covers the upper side of the heater 13.

  The seal top 12 is detachably held and fixed on the seal head 11 by holding mechanisms 23 provided on both sides of the seal head 11 in the width direction. The holding mechanism 23 includes an L-shaped holding member 24 in which a claw 26 that bends substantially perpendicularly to the upper end of a plate-like base 25 is formed, and a lower end of the base 25 of the holding member 24 as a seal head. 11 and a metal bolt 27 as a fixture to be fixed to 11.

  The holding member 24 is integrally formed of a metal material or a synthetic resin material having appropriate flexibility. The base 25 is fastened and fixed in a bolt fastening direction F <b> 1 along the width direction of the seal top 12 in a form extending vertically along the side surface of the seal head 11 by a bolt 27. The claw portion 26 extends in the same direction as the bolt fastening direction F <b> 1 from the upper end of the base portion 25, and the tip thereof is fitted into a groove portion 28 that is recessed on both side surfaces in the width direction of the seal head 11. .

  As shown in FIG. 7, the base 25 is formed with through holes 29 through which the bolts 27 are inserted, and screw holes 30 into which the bolts 27 are screwed are formed on both side surfaces of the seal head 11 in the width direction. Has been. Further, notch grooves 31 for avoiding interference with the claw portions 26 are formed at the upper end portions on both sides in the width direction of the seal head 11.

  FIG. 8 schematically shows the claw portion 26 and the groove portion 28 that are fitted to each other. As shown in FIG. 8A, the tip of the claw portion 26 has a tapered shape in which the lower surface side is inclined upwardly toward the tip, and the lower surface side is directed to the bolt fastening direction F1. Accordingly, an inclined surface portion 32 (second inclined surface) inclined upward is formed. In correspondence with the inclined surface portion 32, a tapered inclined surface portion 33 that is inclined upward as it goes in the bolt fastening direction F1 is also formed on the lower surface side of the groove portion 28. Both inclined portions 32 and 33 are inclined surfaces inclined at substantially the same angle so as to be in surface contact with each other. Further, the vertical dimension L1 of the groove part 28 is set sufficiently larger (for example, twice or more) than the vertical dimension L2 of the claw part 26. Therefore, the inclined surface portion 33 of the groove portion 28 is larger than the inclined surface portion 32 of the claw portion 26.

  When the holding member 24 is tightened to the screw hole 30 of the seal head 11 with the bolt 27, the claw portion 26 moves toward the groove portion 28 in the bolt fastening direction F1, and first, as shown in FIG. The inclined surface portion 32 of the claw portion 26 contacts the lower portion of the inclined surface portion 33 of the groove portion 28. At this time, the bolt 27 is not yet completely tightened, and there is still room for movement to some extent in the bolt fastening direction F1.

  Thereafter, when the bolt 27 is further tightened, as shown in FIG. 8C, the tip of the claw portion 26 is pushed in the bolt fastening direction F1 and enters the groove portion 28 while the holding member 24 is deformed. Go. At this time, the inclined surface portion 32 of the claw slides on the inclined surface portion 33 of the groove portion 28 so as to rise obliquely upward. At this time, the inclination of the inclined surface portions 32 and 33 causes the seal top from the holding member 24. A downward force acts on 12 and the seal top 12 is pressed against the seal head 11 side below the seal top 12. As a result, the seal top 12 is pressed and fixed onto the bottom surface of the deep bottom portion 19 of the seal head 11 via a shim 21 described later.

  Note that the tip shape of the claw portion 26 does not necessarily have the inclined surface portion 32. For example, as shown by a broken line 32A in FIG. 8A, the tip shape of the claw portion 26 is a rectangular shape without the inclined surface portion 32. Even in the case of the shape, a downward force can be obtained by the inclined surface portion 33 of the groove portion.

  Referring to FIG. 6 again, between the bottom surface of the seal top 12 and the bottom surface of the shallow bottom portion 18, an appropriate number of metal thin shims 21 are interposed as gap adjusting members. The height position of the seal top 12 relative to the seal head 11 can be adjusted by adjusting the thickness and number of the shims 21. Note that the shim 21 is omitted in FIGS. Further, a plurality (two in the illustrated example) of shims 21 are provided in advance before adjustment so that the height of the seal top 12 can be reduced.

  In consideration of such height variation due to the shim 21, in the holding mechanism 23, the vertical dimension L1 of the opening of the groove 28 is sufficiently larger than the vertical dimension L2 of the claw 26 (for example, twice or more). And the depth of the groove portion 28 in the bolt axial direction F1 is also set sufficiently large. Therefore, regardless of the height adjustment by the shim 21, the claw portion 26 can be satisfactorily inserted into the groove portion 28, and the opening portion of the groove portion 28 in which the tip of the claw portion 26 is widely opened at the time of bolt fastening. Thus, it can be surely inserted into the groove 28.

  By varying the thickness and number of shims 21 arranged on both sides in the width direction of the seal top 12, the height of the seal top 12 can be varied in the width direction, that is, tilted in the width direction. Further, by disposing the shim 21 only on one side in the longitudinal direction of the seal top 12, the height of the seal top can be varied in the longitudinal direction, that is, it can be inclined in the longitudinal direction. Therefore, the press surface 12a of the heat sealer 10 arranged above and below the object seems to be inclined in the longitudinal direction or the width direction due to an error or variation in dimensional accuracy of each part of the facility, variation due to mold processing accuracy, or the like. Even in such a case, it is possible to adjust the position of the seal top 12 including such an inclination, and the sealing thickness of the laminate film outer package 4 that is the object can be made uniform with high accuracy.

  FIG. 9 shows a seal top holding structure according to a comparative example. As a structure for pressing and fixing the seal top 12H downward on the seal head 11H with the heater 13H interposed therebetween, this downward direction is generally set in the fastening direction F2 of the bolt 27H as in the comparative example shown in FIG. It is conceivable to fix both together. However, in this case, it is necessary to provide the seal top 12H with a bolt insertion flange 35 that is fastened together with the bolt boss portion 34 on the seal head 11H side, and the seal top 12H has a large and complicated shape. For this reason, it is difficult to ensure rigidity against pressure, and the heat capacity increases due to the increase in size, resulting in a large loss of heat energy.

  In contrast to such a comparative example, in the holding structure of the seal top 12 of the present embodiment, the inclined surface portion 33 set to the fitting portion between the claw portion 26 and the groove portion 28 with the bolt fastening direction F1 being the width direction of the seal top 12. 34, a downward force is applied, so that the shape of the seal head 11 can be a very simple substantially rectangular parallelepiped shape except that the groove portion 28 is provided on the side surface. For this reason, the heating time and heating energy by the heater 13 can be suppressed by reducing the heat capacity by reducing the volume while improving the rigidity and strength.

  In addition, in the present embodiment, the heater 13 is interposed between the seal head 11 and the seal top 12, and the pressure is not directly applied to the heater 13 accommodated in the deep bottom portion 19 of the seal head 11. Therefore, the durability and life of the heater 13 can be improved.

  Further, the upper and lower surfaces of the heater 13 are covered by the first protective layer 16 and the second protective layer 17, and the heater 13 does not directly contact the seal head 11 and the seal top 12, and the protective layers 16 and 17 having a low friction coefficient. It is configured to touch. Therefore, when the heater 13 expands / shrinks due to heating, the heater 13 does not slide directly with the seal top 12 or the seal head 11, and the friction of the heater 13 due to this sliding can be prevented. . As a result, the durability of the heater 13 is further improved, and basically it is not necessary to replace the heater 13.

  Here, if a certain amount of space exists between the protective layers 16 and 17 and the heater 13, the space becomes empty due to the heating of the heater 13, and the surrounding temperature is excessively high. This may cause a so-called whitening phenomenon in which the surface becomes cloudy. In this embodiment, since the two layers are substantially in contact with each other so that no space is formed between the protective layers 16 and 17 and the heater 13, the occurrence of the whitening phenomenon due to the above-described emptying is suppressed. can do.

  Further, by increasing the thickness of the second protective layer 17 to relatively reduce the thermal conductivity, heat transfer from the heater 13 to the seal head 11 is suppressed, while the thickness of the first protective layer 16 is increased. By reducing the thickness and relatively increasing the thermal conductivity, heat transfer from the heater 13 to the seal top 12 can be promoted, and the seal top 12 can be heated efficiently.

  In addition, you may make it give a difference in thermal conductivity of both by changing the material of the 1st protective layer 16 and the 2nd protective layer 17. FIG. That is, the first protective layer 16 may be made of a material having high thermal conductivity, and the second protective layer 17 may be made of a material having low thermal conductivity.

  Further, since the first protective layer 16 is coated on the entire surface of the seal top 12, the first protective layer 16 is also provided on the press surface 12a, and the laminate film 4a, which is an object to be thermally welded, The effect which prevents sticking with 4b can also be acquired collectively.

  Furthermore, since the seal top 12 is made of a metal such as stainless steel, heat is easily transferred during welding, and since thermal expansion is small, the welding quality is stabilized.

  If the seal top is omitted and the heater (or the glass tape that attaches the heater to the seal head) is pressed directly against the laminate film, the chamfered part with an appropriate radius of curvature is provided on both sides of the press surface. It is difficult to provide and there is a risk of damaging the laminate film. In the present embodiment, a metal seal top 12 that is wider and thicker than the heater 13 is provided on the heater 13, and the press surface 12 a is provided on the seal top 12. It is possible to easily form the chamfered portions 14 having a predetermined radius of curvature on both side edges by machining.

  And since the insulation of both can be ensured by the 1st protective layer 16 interposed between the heater 13 and the metal seal top 12, it heats up the seal top 12 safely and reliably by electricity supply, without causing an electric shock. be able to.

  Next, the structure forming the main part of the present embodiment will be described. As shown in FIGS. 5 and 6, the metal seal head 11 is provided with a deep bottom portion 19 as a housing portion for housing the heater 13. The deep bottom portion 19 is provided on both sides of the deep bottom portion 19. A bottom surface of the shallow bottom portion 18 is provided as a convex portion formed in a stepped shape so as to protrude upward from the position 19. On the bottom surface of the shallow bottom portion 18, the bottom surface of the metal seal top 12 is fixed via a metal shim 21, and the seal head 11 and the seal top 12 are rigidly connected by metal. It has become. That is, the second protective layer 17 is omitted from the upper surface of the shallow bottom portion 18 of the seal head 11 in contact with the bottom surface of the seal top 12 so as to be in a metal-connected state. In addition, the first protective layer 16 of the seal top 12 has a structure in which the portion in contact with the seal head 11 is omitted by masking processing, like the second protective layer 17, in order to further improve the positional accuracy.

  By directly connecting and connecting the seal top 12 and the seal head 11 with metal in this way, the pressure of the pressing device can be adjusted with the metal seal head 11 without using the second protective layer 17 that is an elastic layer. The workpiece can be directly transmitted to the workpiece via the seal top 12. As a result, the welding thickness becomes uniform, and high-quality welding without variation between shots is possible.

  In addition, since the height of the bottom surface of the shallow bottom portion 18 is set to be equal to the thickness of the heater 13 including the thickness of the coating of the first protective layer 16, the heater 13 may be directly subjected to the pressure of the press device. In addition, the heater 13 is prevented from being deformed, disconnected, or worn, and can be used stably over a long period of time. If the gap between the heater 13 and the seal top 12 or the seal head 11 causes a wide problem, the gap may be filled with a heat transfer material such as a thermal joint.

  The seal top 12 has a simple rectangular parallelepiped shape except for a groove 28 for fixing. For this reason, the temperature of the heater 13 is easily received and the temperature is likely to rise uniformly. As a result, the welding thickness is uniform, and high-quality welding without variation between shots is possible. If the seal top has a complex shape with irregularities, heat escapes there, lowering the temperature of the seal surface and lowering the welding quality.

  Since the seal top 12 is made of metal, it has excellent heat resistance and strength unlike ceramics, etc., and can be used for a long time without cracking or deforming even when high pressure is repeatedly applied by a press device. . Moreover, since the metal is excellent in heat storage property, the heating time at the next welding can be shortened. As a result, the effect of shortening the cycle time and reducing the energy cost can be obtained.

  FIG. 10 is a cross-sectional view of the portion along the line BB in FIG. 1, and FIG. 11 is a cross-sectional view of the portion along the line AA in FIG. In FIGS. 10 and 11, the groove 28 is omitted for simplicity. As shown in FIGS. 10 and 11, the heater 13 has a width-direction dimension orthogonal to the longitudinal direction that differs depending on the position in the longitudinal direction. That is, the width direction dimension D1 at the longitudinal position in FIG. 10 is set longer than the width direction dimension D2 at the longitudinal position in FIG. 11 (D1> D2). Thus, by partially changing the width of the heater 13, the resistance value of the heater 13 is changed, and the heat generation temperature can be changed. For example, in the same work, as shown in FIG. 11, since heat easily escapes in the portion where the lead terminals 2 and 3 exist, the width direction dimension of the heater 13 is shortened for the purpose of keeping the welding temperature high. Increase the temperature relatively. On the other hand, as shown in FIG. 10, in a portion where the lead terminals 2 and 3 do not exist, the temperature can be set low by increasing the width direction dimension of the heater 13 in order to prevent whitening of the laminate film due to high temperature. it can. At this time, the width direction dimension of the deep bottom portion 19 of the seal head 11 that accommodates the heater 13 is set in advance in accordance with the portion having the longest width direction dimension D1 of the heater 13, so that the heaters having different width direction dimensions can be obtained. 13 is possible.

  FIG. 12 shows a second embodiment of the present invention. In this embodiment, in order to improve the positional accuracy between the seal top 12 and the seal head 11, as in the first embodiment, the first protective layer 16 and the second protective layer 16 are formed at the portion where the seal top 12 and the seal head 11 are in contact. Both of the protective layers 17 are omitted or eliminated by masking, and the first protective layer 16 is coated only on the upper surface side in contact with the workpiece to prevent the seal top 12 from sticking. Instead, the surface of the heater 13 is coated with a protective layer 40 such as Teflon (registered trademark) over the entire surface.

  FIG. 13 shows a third embodiment of the present invention. In the third embodiment, the first protective layer 16 is provided over the entire surface of the seal top 12 except for the portion where the seal head 11 and the seal top 12 are in direct contact, and the second protection is performed over the entire surface of the seal head 11. Layer 17 is provided. Even in this case, since the metal seal head 11 and the seal top 12 are in a rigidly coupled state, that is, in a state where they are connected by metal, the same action as in the first and second embodiments is performed. An effect can be obtained.

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes. For example, in the above embodiment, the protective layers 16 and 17 are formed by a coating process. However, the method of providing the protective layer is not limited to this. For example, a thin protective layer separate from the seal head 11 and the seal top 12 is used. You may make it interpose between the heaters 13.

  In the above embodiment, the present invention is applied to a pair of upper and lower heat sealers having the same structure. However, the upper and lower heat sealers may have different structures, and the present invention may be applied to only one heat sealer.

Claims (5)

A seal head;
A seal top supported on the seal head and having a pressing surface for pressing an object on the upper surface;
A thin plate-like heater interposed between the upper surface of the seal head and the lower surface of the seal top and generating heat by energizing current to heat the seal top,
In a heat sealer that welds by melting the object by pressing with a heated seal top,
Both the seal head and the seal top are made of metal,
On the opposing surfaces of the seal head and the seal top, an accommodating portion for accommodating the heater is formed,
And the seal head and the seal top are connected by metal,
A heat sealer in which a protective layer having an insulating property is coated on at least one surface of the seal head and the seal top except for a portion where the seal head and the seal top are in contact with each other.   The heat sealer according to claim 2, wherein the protective layer is coated on both surfaces of the seal head and the seal top.   The heat sealer according to claim 2 or 3, wherein the protective layer is a Teflon or fluorine coating. The housing is recessed in the seal head;
The heat sealer according to any one of claims 2 to 4, wherein the seal top has a rectangular parallelepiped shape. The heater has a portion in which the width direction perpendicular to the longitudinal direction differs in the longitudinal direction,
The heat sealer according to any one of claims 2 to 5, wherein a dimension in the width direction of the housing portion is set according to a dimension in the widest width direction of the heater.

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