Method for joining members made of material containing thermoplastic resin
Patent Information
- Application Number
- CA3316624
- Authority / Receiving Office
- CA · CA
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-02-26
- Publication Date
- 2026-08-05
Abstract
Description
DESCRIPTION Title of the Invention: METHOD FOR JOINING MEMBERS MADE OF MATERIAL CONTAINING THERMOPLASTIC RESIN Technical Field
[0001] The present disclosure relates to a method for joining members made of a material containing a thermoplastic resin such as, for example, a thermoplastic resin composite material. Background Art
[0002] As a method for joining members made of a material containing a thermoplastic resin, a method of heating two members to be joined to melt the thermoplastic resin contained in both the members to join both the members via the molten thermoplastic resin, that is, direct heat welding, has been proposed.
[0003] As a method for joining a first member and a second member both made of a material containing a thermoplastic resin, Patent Document 1 proposes a method of placing the first member on a first heat source, placing the second member on the first member, positioning a second heat source above the second member, then lowering the second heat source, and pressing a lower surface of the second heat source against an upper surface of the second member. At this time, the temperature of the first heat source is set to a temperature lower than a melting point of the thermoplastic resin, while the temperature of the second heat source is set to a temperature higher than the melting point of the thermoplastic resin and lower than a thermal decomposition temperature.
[0004] By setting the temperatures of the first heat source and the second heat source as described above, a portion at a temperature equal to or higher than the melting point of the thermoplastic resin, of members to be joined (the first member and the second member), is limited to the second member and a vicinity of a joint surface of both the members. That is, regarding the first member of the members to be joined, the temperature of a portion excluding the vicinity of the joint surface is suppressed to a temperature lower than the melting point of the thermoplastic resin. Therefore, while welding is reliably performed on the joint surface, the flow of the thermoplastic resin is suppressed at other portions of the first member, and deformation of the members to be joined can be prevented.
[0005] In addition, Patent Document 1 proposes measures for preventing the members to be joined from being deformed due to the flow of the thermoplastic resin inevitably generated in the vicinity of the joint surface of the members to be joined.
[0006] According to a first measure, a recessed portion having a shape capable of accommodating a portion to be joined (a portion located above the joint surface) of the second member is provided in the lower surface of the second heat source. When the second heat source descends and a portion of the lower surface excluding the recessed portion comes into contact with the upper surface of the first member, the portion to be joined of the second member is accommodated in a space surrounded by an inner surface of the recessed portion and the upper surface of the first member. Therefore, even in a case where the flow of the thermoplastic resin occurs in the vicinity of the joint surface, the flow is limited in the space, so that deformation of the members to be joined can be prevented.
[0007] A second measure is to place a U-shaped jig in plan view on the upper surface of the first member so as to surround the portion to be joined of the second member from three sides. In a state where the second heat source descends and the lower surface of the second heat source is in contact with an upper surface of the portion to be joined of the second member, the portion to be joined of the second member is surrounded from three sides by an inner surface of the jig on the upper surface of the first member. Therefore, even in the case where the flow of the thermoplastic resin occurs in the vicinity of the joint surface, the flow is stopped by the inner surface of the jig, and deformation of the members to be joined can be prevented. Related Art Document Patent Document
[0008] Patent Document 1: JP 2023-105471 A Summary of the Invention Problems to be solved by the Invention
[0009] As described above, Patent Document 1 proposes the two measures for preventing deformation of the members to be joined due to flow of the thermoplastic resin inevitably generated in the vicinity of the joint surface.
[0010] However, in the first measure, in a case where there is particularly a difference in dimension in an up- down direction between the recessed portion provided in the lower surface of the second heat source and the portion to be joined of the second member due to manufacturing tolerance or the like, deformation of the members to be joined cannot be necessarily effectively prevented. That is, in a case where the dimension in the up-down direction of the recessed portion is larger than the dimension in the up-down direction of the portion to be joined, a gap is generated between an upper inner surface (ceiling surface) of the recessed portion and the upper surface of the portion to be joined, and conversely, in a case where the dimension in the up-down direction of the recessed portion is smaller than the dimension in the up-down direction of the portion to be joined, the recessed portion cannot completely accommodate the portion to be joined, and a gap is generated between the lower surface of the second heat source and the upper surface of the first member. Therefore, in either case, the thermoplastic resin in a flowing state in the vicinity of the joint surface flows out into the gap described above.
[0011] In addition, also in the second measure, since the jig described above is merely placed on the upper surface of the first member in a state of not moving in a horizontal direction, deformation of the members to be joined cannot be necessarily effectively prevented. That is, in a case where the thermoplastic resin melted in a portion of the first member in the vicinity of the joint surface flows out onto the upper surface of the first member, if an outflow pressure exceeds a surface pressure due to the jig's own weight, the jig is lifted up, and a gap is generated between the jig and the upper surface of the first member. Therefore, the thermoplastic resin in the flowing state in the vicinity of the joint surface flows out of a region surrounded by the jig through the gap described above.
[0012] As described above, it can be said that the method proposed in Patent Document 1 has room for further improvement from the viewpoint of suppressing the outflow of the thermoplastic resin in a fluid state in the vicinity of the joint surface and preventing the deformation of the members to be joined.
[0013] The present disclosure has been made on the basis of the above consideration, and an object of the present disclosure is to provide a method for joining two members made of a material containing a thermoplastic resin by direct thermal welding, the method capable of reliably preventing deformation of the two members due to flow of the thermoplastic resin. Means for Solving the Problems
[0014] To solve the above-described problems, a method according to the present disclosure is for joining a first member and a second member both made of a material containing a thermoplastic resin, and the method includes, in sequence: (a) a step of placing the first member on an upper surface of a first heat source; (b) a step of placing the second member on an upper surface of the first member and bringing a portion to be joined of the second member into contact with the upper surface of the first member; (c) a step of placing a heat-insulating material on an upper surface of the portion to be joined of the second member such that a surface of the heat-insulating material is in close contact with a surface of the second member; (d) a step of placing a second heat source having a notched portion on the heat-insulating material and on the upper surface of the portion to be joined of the second member such that the surface of the heat-insulating material is in close contact with an inner surface of the notched portion; (e) a step of applying a downward load of desired magnitude to the second heat source and the heat-insulating material; (f) a step of placing a first resin flow prevention jig and a second resin flow prevention jig on the upper surface of the first member so as to surround the portion to be joined of the second member in cooperation with each other; (g) a step of applying a downward load of desired magnitude to the first resin flow prevention jig and the second resin flow prevention jig; (h) a step of heating the first heat source to a predetermined first temperature and heating the second heat source to a predetermined second temperature; and (i) a step of cooling the first member and the second member after a predetermined retention time has elapsed since a temperature of the first heat source reached the first temperature and a temperature of the second heat source reached the second temperature, in which the second temperature is higher than a weldable temperature of the thermoplastic resin and lower than a degradation temperature of the thermoplastic resin, and the first temperature is lower than the weldable temperature of the thermoplastic resin. Advantageous Effects of the Invention
[0015] According to the present disclosure, when two members made of a material containing a thermoplastic resin are joined by direct thermal welding, it is possible to obtain an excellent effect of reliably preventing deformation of both the members due to flow of a thermoplastic resin. Brief Description of the Drawings
[0016] FIG. 1 is a schematic perspective view illustrating an arrangement state of two members made of a material containing a thermoplastic resin and equipment for joining the two members at the time of performing joining by a method according to a first embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view at a center in a width direction (w direction in FIG. 1) of members to be joined, illustrating a main part of the arrangement state of two members made of a material containing a thermoplastic resin and equipment for joining the two members at the time of performing joining by the method according to the first embodiment of the present disclosure. FIG. 3A is a schematic perspective view illustrating a first stage in an arrangement procedure of the members and equipment for performing joining by the method according to the first embodiment of the present disclosure. FIG. 3B is a schematic perspective view illustrating a second stage in the arrangement procedure of the members and equipment for performing joining by the method according to the first embodiment of the present disclosure. FIG. 3C is a schematic perspective view illustrating a third stage in the arrangement procedure of the members and equipment for performing joining by the method according to the first embodiment of the present disclosure. FIG. 3D is a schematic perspective view illustrating a fourth stage (final stage) in the arrangement procedure of the members and equipment for performing joining by the method according to the first embodiment of the present disclosure. FIG. 4 is a schematic perspective view illustrating an arrangement state of two members made of a material containing a thermoplastic resin and equipment for joining the two members at the time of performing joining by a method according to a second embodiment of the present disclosure. FIG. 5 is a schematic cross-sectional view at a center in a width direction (w direction in FIG. 4) of members to be joined, illustrating a main part of the arrangement state of two members made of a material containing a thermoplastic resin and equipment for joining the two members at the time of performing joining by the method according to the second embodiment of the present disclosure. FIG. 6A is a schematic perspective view illustrating a first stage in an arrangement procedure of the members and equipment for performing joining by the method according to the second embodiment of the present disclosure. FIG. 6B is a schematic perspective view illustrating a second stage in the arrangement procedure of the members and equipment for performing joining by the method according to the second embodiment of the present disclosure. FIG. 6C is a schematic perspective view illustrating a third stage in the arrangement procedure of the members and equipment for performing joining by the method according to the second embodiment of the present disclosure. FIG. 6D is a schematic perspective view illustrating a fourth stage in the arrangement procedure of the members and equipment for performing joining by the method according to the second embodiment of the present disclosure. FIG. 6E is a schematic perspective view illustrating a fifth stage (final stage) in the arrangement procedure of the members and equipment for performing joining by the method according to the second embodiment of the present disclosure. FIG. 7 is a schematic perspective view illustrating shapes and a clamping mode of two clamping jigs used in joining by the method according to the second embodiment of the present disclosure. FIG. 8 is a schematic cross-sectional view at a center in a width direction of members to be joined, illustrating a main part of an arrangement state of two members made of a material containing a thermoplastic resin and equipment for joining the two members at the time of performing joining by a method according to a third embodiment of the present disclosure. Mode for Carrying out the Invention
[0017] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.
[0018] First, a joining method according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1, 2, and 3A to 3D.
[0019] FIGS. 1 and 2 illustrate two members (members to be joined) made of a material containing a thermoplastic resin and an arrangement state of equipment for joining the two members at the time of performing the joining by the method according to the first embodiment of the present disclosure. FIG. 1 is a schematic perspective view and FIG. 2 is a schematic cross-sectional view at a center in a width direction (w direction in FIG. 1) of the members to be joined. Further, FIGS. 3A to 3D are schematic perspective views illustrating first to fourth stages of an arrangement procedure (to be described below) of the members and the equipment illustrated in FIG. 1, and clearly illustrating shapes and mutual positional relationships of the members and the equipment.
[0020] These drawings illustrate a state when a second member M2 made of a material containing a thermoplastic resin is joined to an upper surface M1U of a first member M1 similarly made of a material containing a thermoplastic resin.
[0021] The material containing a thermoplastic resin may be, for example, carbon fiber reinforced plastic (CFRP) including a thermoplastic resin (by way of example, polyetheretherketone (PEEK)) as a base material and carbon fibers as a reinforcing material, but any material containing a thermoplastic resin may be used. Note that the thermoplastic resins contained in the first member M1 and the second member M2 are preferably the same.
[0022] Each of the first member M1 and the second member M2 is molded in advance using a molding die. In the illustrated embodiment, the first member M1 is a relatively large member having a flat plate shape (the thickness is, for example, 2 to 3 mm), and the second member M2 is a relatively small plate-like member having an L shape (the thickness is, for example, 2 to 3 mm) (particularly, see FIG. 3A).
[0023] As illustrated in FIGS. 2 and 3A, in the second member M2, a portion to be joined M2W joined to the upper surface M1U of the first member M1 is a flat plate-like portion corresponding to one side (a short side in the illustrated embodiment) of the L shape. Meanwhile, an upright portion M2V corresponding to the other side (a long side in the illustrated embodiment) of the L shape is oriented perpendicular to the portion to be joined M2W. The portion to be joined M2W and the upright portion M2V are connected to each other via an arc-shaped curved portion M2R.
[0024] Note that a direction from the portion to be joined M2W to the upright portion M2V via the curved portion M2R (or an opposite direction of the direction) is referred to as a longitudinal direction of the second member M2, and a direction perpendicular to the longitudinal direction is referred to as a width direction of the second member M2 (the width direction coincides with the w direction in FIG. 1). In addition, for the equipment other than the second member M2, a direction coinciding with the width direction of the second member M2 is referred to as a width direction, and a dimension in the width direction is referred to as a width.
[0025] As illustrated in FIGS. 2 and 3A, the first member M1 is placed on an upper surface H1U of a first heat source H1, and the second member M2 is placed on an upper surface M1U of the first member M1.
[0026] The first heat source H1 is a flat panel-like equipment, and the upper surface H1U of the first heat source H1 is formed to have a shape and a size with which an entire lower surface of the first member M1 can be in close contact.
[0027] A heater and a temperature sensor (both not illustrated) are embedded in the first heat source H1. Among them, the temperature sensor is embedded so that a temperature sensing part is located in a vicinity immediately below the upper surface H1U in contact with a lower surface of the portion to be joined M2W of the second member M2.
[0028] As illustrated in FIGS. 1 and 2 and FIGS. 3B and 3C, a second heat source H2 and a heat-insulating material IS are placed on an upper surface of the portion to be joined M2W of the second member M2.
[0029] The second heat source H2 is a substantially rectangular parallelepiped equipment, the width of which is substantially equal to the width of the portion to be joined M2W of the second member M2, and a notched portion H2R is provided in a lower part of the second heat source H2. The notched portion H2R is a space opened on a bottom surface, a front surface, and both side surfaces in the width direction, of the second heat source H2, and the height of the notched portion H2R is equal to the height of the heat-insulating material IS to be described below. Here, the front surface of the second heat source H2 is a surface facing the upright portion M2V of the second member M2. The notched portion H2R is formed to accommodate a part of the heat-insulating material IS in a state where a surface of the heat-insulating material IS is in close contact with an inner surface of the notched portion H2R.
[0030] A heater and a temperature sensor (both not illustrated) are embedded in the second heat source H2. Among them, the temperature sensor is embedded so that a temperature sensing part is located in a vicinity immediately above a lower surface of the second heat source Н2.
[0031] Although not illustrated, a load applying mechanism for applying a downward load <semantics>LH2<annotation encoding="application / x-tex">L_{H2}< / annotation>< / semantics> (see the arrow in FIG. 2) in a state where the lower surface of the second heat source H2 is in contact with the upper surface of the portion to be joined M2W of the second member M2 is attached to the second heat source H2. Note that, when the downward load <semantics>LH2<annotation encoding="application / x-tex">L_{H2}< / annotation>< / semantics> is applied to the second heat source H2, the downward load <semantics>LH2<annotation encoding="application / x-tex">L_{\text{H2}}< / annotation>< / semantics> is simultaneously applied to the heat-insulating material IS accommodated in the notched portion H2R provided in the lower part of the second heat source H2 as described above.
[0032] The heat-insulating material IS is a substantially rectangular parallelepiped equipment made of a material having high heat-insulating properties, has a width substantially equal to the portion to be joined M2W of the second member M2, and is configured such that a part (preferably having an area that is 1 / 2 or more in a projected area in a vertical direction) of the heat- insulating material IS is accommodated in the notched portion H2R of the second heat source H2.
[0033] In the state illustrated in FIG. 1 and 2 (that is, a state where joining is performed), the surfaces (the front surface and the bottom surface) of the heat- insulating material IS opposite to the notched portion H2R of the second heat source H2 are shaped to be in close contact with the surfaces of the upright portion M2V, the curved portion M2R, and the portion to be joined M2W of the second member M2. This is for exerting a heat-insulating effect in order to control conduction of heat applied from the second heat source H2 on the upper surface of the portion to be joined M2W to the second member M2 in the longitudinal direction. Therefore, the height of the heat- insulating material IS is set to a value that can suppress the heat conduction so that the temperature of the upright portion M2V does not excessively rise due to the heat conduction described above (specifically, at least the thermoplastic resin is prevented from being flowable).
[0034] Next, core features of the present disclosure for solving the problem of reliably preventing deformation of the members to be joined due to flow of the thermoplastic resin in the vicinity of a joint surface will be described below.
[0035] As illustrated in FIGS. 1, 2, and 3D, a first resin flow prevention jig J1 and a second resin flow prevention jig J2 are placed on the upper surface M1U of the first member M1. More specifically, the first resin flow prevention jig J1 is placed on the upper surface M1U of the first member M1 on the same side as the portion to be joined M2W, and the second resin flow prevention jig J2 is placed on the upper surface M1U of the first member M1 on the opposite side to the portion to be joined M2W, with respect to the upright portion M2V of the second member M2 (see FIG. 2). Note that the first resin flow prevention jig J1 and the second resin flow prevention jig J2 preferably include a material having high heat-insulating properties.
[0036] The first resin flow prevention jig J1 is a member formed in a U-shape in plan view, and includes a base portion J1B extending in the width direction and two arm portions J1A extending in the longitudinal direction of the second member M2 from both end portions of the base portion J1B as starting points. Further, the first resin flow prevention jig J1 is formed to have a thickness larger than the portion to be joined M2W of the second member M2.
[0037] The first resin flow prevention jig J1 defines a space surrounded by three sides by the base portion J1B and the two arm portions J1A, and surfaces of the base portion J1B and the two arm portions J1A, the surfaces facing the space, are referred to as respective inner surfaces of the base portion J1B and the two arm portions J1A.
[0038] At this time, the inner surface of the base portion J1B is in close contact with an end surface of the portion to be joined M2W of the second member M2 in the longitudinal direction, and the width of the base portion J1B is formed to be substantially equal to the width of the portion to be joined M2W of the second member M2.
[0039] Meanwhile, the inner surfaces of the two arm portions J1A are in close contact with end surfaces of the portion to be joined M2W of the second member M2 in the width direction in a state where there is substantially no gap. In addition, each of the two arm portions J1A extends to the opposite side of the portion to be joined M2W with respect to the upright portion M2V of the second member M2. Note that the state where there is substantially no gap does not exclude the presence of a gap inevitably generated due to manufacturing tolerance of the second member M2.
[0040] The second resin flow prevention jig J2 is a substantially rectangular parallelepiped member having a width substantially equal to the width of the upright portion M2V of the second member M2. As described above, both end surfaces of the second resin flow prevention jig J2 in the width direction are formed so as to be in close contact with the inner surfaces of the two arm portions J1A of the first resin flow prevention jig J1 extending from an opposite side with respect to the upright portion M2V of the second member M2. In addition, a surface of the second resin flow prevention jig J2, the surface facing the second member M2, is shaped to be in close contact with the surfaces of the upright portion M2V and the curved portion M2R of the second member M2 in the state where there is substantially no gap in the state illustrated in FIG. 2 (that is, the state where joining is performed). Here as well, the state where there is substantially no gap does not exclude the presence of a gap inevitably generated due to manufacturing tolerance of the second member M2.
[0041] Since the first resin flow prevention jig J1 and the second resin flow prevention jig J2 are configured as described above, the first resin flow prevention jig J1 and the second resin flow prevention jig J2 surround the portion to be joined M2W of the second member M2 and the vicinity of the portion to be joined M2W in cooperation.
[0042] Although not illustrated, a load applying mechanism for applying a downward load LJ1 (see the arrow in FIG. 2) is attached to the first resin flow prevention jig J1, and a load applying mechanism for applying a downward load <semantics>LJ2<annotation encoding="application / x-tex">L_{J2}< / annotation>< / semantics> (see the arrow in FIG. 2) is attached to the second resin flow prevention jig J2. These load applying mechanisms are provided separately from the above- described load applying mechanism for applying the downward load <semantics>LH2<annotation encoding="application / x-tex">L_{H2}< / annotation>< / semantics> to the second heat source H2.
[0043] Heater lead wire and temperature sensor lead wire embedded in the first heat source H1 and the second heat source H2 are connected to a general-purpose temperature controller (not illustrated), and the temperatures of the first heat source H1 and the second heat source H2 are controlled by the temperature controller as will be described below while joining is performed.
[0044] In addition, the downward loads respectively applied to the second heat source H2, the first resin flow prevention jig J1, and the second resin flow prevention jig J2 by the unique load applying mechanisms are controlled by a controller (not illustrated).
[0045] Although not illustrated, in order to cool the first member M1 and the second member M2 after completion of joining, a blower capable of blowing air to the entire first member M1 and the second member M2 is installed.
[0046] The first member M1 and the second member M2 are joined by the method according to the first embodiment of the present disclosure using the first heat source H1, the second heat source H2, the first resin flow prevention jig J1, and the second resin flow prevention jig J2 described above, and details of the joining will be described below.
[0047] Here, it is assumed that the first member M1 and the second member M2 contain the same thermoplastic resin, and attention is paid to the following two temperatures as temperatures that characterize the thermal properties of the thermoplastic resin. -Degradation temperature (Th): temperature at which degradation of the thermoplastic resin occurs -Weldable temperature (Tm): lowest temperature at which welding is possible, for example, a melting point or a glass transition temperature Note that a relationship of Th > Tm normally holds.
[0048] In the joining by the method according to the embodiment of the present disclosure, the temperature (first temperature) T1 of the first heat source H1 is made lower than the weldable temperature Tm of the thermoplastic resin, and at the same time, the temperature (second temperature) T2 of the second heat source H2 is made higher than the weldable temperature Tm of the thermoplastic resin and lower than the degradation temperature Th of the thermoplastic resin, so that the temperature of a joint region between the first member M1 and the second member M2 located between the two heat sources reaches the weldable temperature Tm of the thermoplastic resin. As a result, both the members can be welded in a joint region, that is, a region between a first joint surface (the portion of the upper surface M1U of the first member M1, the portion facing the lower surface of the portion to be joined M2W of the second member M2) and a second joint surface (the lower surface of the portion to be joined M2W of the second member M2).
[0049] In the joining by the method according to the first embodiment of the present disclosure, the temperatures measured by the temperature sensors embedded in the first heat source H1 and the second heat source H2 are controlled by the above-described temperature controller to be the first temperature T1 and the second temperature T2, respectively.
[0050] During the joining, the downward loads <semantics>LH2<annotation encoding="application / x-tex">L_{H2}< / annotation>< / semantics>, <semantics>LJ1<annotation encoding="application / x-tex">L_{J1}< / annotation>< / semantics>, and <semantics>LJ2<annotation encoding="application / x-tex">L_{J2}< / annotation>< / semantics> respectively applied to the second heat source H2, the first resin flow prevention jig J1, and the second resin flow prevention jig J2 are controlled by the above- described controller to have desired magnitudes.
[0051] The joining by the method according to the first embodiment of the present disclosure is performed by executing the following steps in sequence. (a) a step of placing the first member M1 on the upper surface H1U of the first heat source H1 (a first stage in the arrangement procedure of the members and the equipment; see FIG. 3A) (b) a step of placing the second member M2 on the upper surface M1U of the first member M1 and bringing the portion to be joined M2W into contact with the upper surface M1U of the first member M1 (the first stage in the arrangement procedure of the members and the equipment; see FIG. 3A) (c) a step of placing the heat-insulating material IS on the upper surface of the portion to be joined M2W of the second member M2 such that the surface of the heat- insulating material IS is in close contact with the surface of the second member M2 (a second stage in the arrangement procedure of the members and the equipment; see FIG. 3B) (d) a step of placing the second heat source H2 on the heat-insulating material IS and the upper surface of the portion to be joined M2W of the second member M2 so that the surface of the heat-insulating material IS is in close contact with the inner surface of the notched portion H2R (a third stage in the arrangement procedure of the members and the equipment; see FIG. 3C) (e) a step of controlling, by a controller, the unique load applying mechanism such that the downward load to be applied to the second heat source H2 (and the heat- insulating material IS) has desired magnitude (f) a step of placing the first resin flow prevention jig J1 and the second resin flow prevention jig J2 on the upper surface M1U of the first member M1 so as to surround the portion to be joined M2W of the second member M2 in cooperation (a fourth stage (final stage) in the arrangement procedure of the members and the equipment; see FIG. 3D) (g) a step of controlling, by the controller, the load applying mechanism unique to each of the first resin flow prevention jig J1 and the second resin flow prevention jig J2 such that the downward load to be applied to each of the first resin flow prevention jig J1 and the second resin flow prevention jig J2 has desired magnitude (h1) a step of heating the first heat source H1 to the first temperature T1 (controlling, by the temperature controller, ON / OFF of the heater embedded in the first heat source H1 such that the temperature measured by the temperature sensor embedded in the first heat source H1 becomes the first temperature T1) (h2) a step of heating the second heat source H2 to the second temperature T2 (controlling, by the temperature controller, ON / OFF of the heater embedded in the second heat source H2 such that the temperature measured by the temperature sensor embedded in the second heat source H2 becomes the second temperature T2) (i) a step of cooling the first member M1 and the second member M2 (by blowing air using the blower) after a predetermined retention time has elapsed since the temperature measured by the temperature sensor embedded in the first heat source H1 reached the first temperature T1 and the temperature measured by the temperature sensor embedded in the second heat source H2 reached the second temperature T2
[0052] In the joining by the above-described method, the portion to be joined M2W of the second member M2 and the vicinity of the portion to be joined M2W are completely surrounded by the first resin flow prevention jig J1 and the second resin flow prevention jig J2. The first resin flow prevention jig J1 and the second resin flow prevention jig J2 are pressed against the upper surface M1U of the first member M1 by the downward loads applied by the load applying mechanisms. Therefore, even in a case where the thermoplastic resin becomes able to flow in the vicinity of the lower surface of the portion to be joined M2W of the second member M2 and in the vicinity of the upper surface of the first member M1 facing the lower surface, the thermoplastic resin can be prevented from flowing out to the surroundings, and deformation of the members to be joined can be prevented.
[0053] Since the load applying mechanisms that respectively apply the downward loads to the first resin flow prevention jig J1 and the second resin flow prevention jig J2 are provided separately from the load applying mechanism that applies the downward load to the second heat source H2, the first resin flow prevention jig J1 and the second resin flow prevention jig J2 can be reliably pressed against the upper surface M1U of the first member M1 even in a case where there is a variation in the thickness (the dimension in the up-down direction) of the portion to be joined M2W of the second member M2 due to the manufacturing tolerance. As a result, it is possible to more reliably prevent the thermoplastic resin in a flowable state from flowing out to the surroundings.
[0054] Next, a joining method according to a second embodiment of the present disclosure will be described below with reference to FIGS. 4, 5, 6A to 6E, and 7.
[0055] FIGS. 4 and 5 illustrate an arrangement state of two members (members to be joined) made of a material containing a thermoplastic resin and equipment for joining the two members at the time of performing joining by the method according to the second embodiment of the present disclosure. FIG. 4 is a schematic perspective view and FIG. 5 is a schematic cross-sectional view at a center in a width direction (w direction in FIG. 4) of the members to be joined. Further, FIGS. 6A to 6E are schematic perspective views illustrating first to fifth stages of an arrangement procedure (to be described below) of the members and the equipment illustrated in FIG. 4, and clearly illustrating shapes and mutual positional relationships of the members and the equipment. Further, FIG. 7 is a schematic perspective view illustrating shapes and a clamping mode of two clamping jigs used in joining by the method according to the second embodiment of the present disclosure.
[0056] The joining method according to the second embodiment of the present disclosure is obtained by adding a modification to the joining method according to the first embodiment in order to more reliably prevent deformation of the members to be joined due to flow of the thermoplastic resin in the vicinity of a joint surface.
[0057] The joining method according to the second embodiment of the present disclosure is different from the joining method according to the first embodiment in that the clamping jigs for bringing two resin flow prevention jigs into close contact with a second member M2 are added. Therefore, -shapes and a joining mode of a first member M1 and the second member M2 (members to be joined), -shapes, functions and an arrangement mode with respect to the members to be joined of a first heat source H1 and a second heat source H2, and -shapes and an arrangement mode with respect to members to be joined of a heat-insulating material IS, a first resin flow prevention jig J1, and a second resin flow prevention jig J2 are similar to the joining method according to the first embodiment. Therefore, redundant description will be omitted.
[0058] As illustrated in FIG. 4, in the joining method according to the second embodiment of the present disclosure, a first clamping jig CJ1 and a second clamping jig CJ2 are additionally provided.
[0059] As illustrated in FIG. 5, the first clamping jig CJ1 is a member placed on an upper surface J1U of the first resin flow prevention jig J1 on the same side as a portion to be joined M2W with respect to an upright portion M2V of the second member M2 (see also FIGS. 6C and 6D).
[0060] The first clamping jig CJ1 is a member formed in a U-shape in plan view, and includes a base portion CJ1B extending in the width direction and two arm portions CJ1A extending in a longitudinal direction of the second member M2 from both end portions of the base portion CJ1B as starting points, as illustrated in FIG. 4, and particularly FIG. 7.
[0061] The first clamping jig CJ1 defines a space surrounded by three sides by the base portion CJ1B and the two arm portions CJ1A, and surfaces of the base portion CJ1B and the two arm portions CJ1A, the surfaces facing the space, are referred to as respective inner surfaces of the base portion CJ1B and the two arm portions CJ1A.
[0062] At this time, the inner surface of the base portion CJ1B is located outside an inner surface of a base portion J1B of the first resin flow prevention jig J1, and the inner surfaces of the two arm portions CJ1A are located outside inner surfaces of the two arm portions J1A of the first resin flow prevention jig J1. Here, the "outside" refers to a side away from a surface of the second heat source H2. As a result, the inner surfaces of the base portion CJ1B and the two arm portions CJ1A are disposed separately from an outer surface of the second heat source H2, and the first clamping jig CJ1 is prevented from being excessively heated by heat conduction from the second heat source H2. In addition, as particularly seen in FIG. 5, the first clamping jig CJ1 is configured such that a lower surface of the first clamping jig CJ1 is separated from an upper surface M1U of the first member M1 in a state of being placed on the upper surface J1U of the first resin flow prevention jig J1.
[0063] A notched portion CJ1R is formed in a lower portion of the first clamping jig CJ1. The notched portion CJ1R is formed in such a shape that an inner surface of the notched portion CJ1R is in close contact with at least the upper surface J1U and an outer surface (an end surface in the longitudinal direction of the second member M2) J1E on the side opposite to the inner surface of the base portion J1B, of an exterior of the first resin flow prevention jig J1 (see FIG. 5). As a result, a load can be applied to the first resin flow prevention jig J1 via the inner surface of the notched portion CJ1R of the first clamping jig CJ1 as will be described below.
[0064] As illustrated in FIG. 5, the second clamping jig CJ2 is a member placed on an upper surface J2U of the second resin flow prevention jig J2 on an opposite side to the portion to be joined M2W with respect to the upright portion M2V of the second member M2 (see also FIGS. 6D and 6E).
[0065] As illustrated in FIGS. 4, 5, and particularly FIG. 7, the second clamping jig CJ2 is a member formed in an L shape in side view in the width direction, and a notched portion CJ2R is formed in a lower portion of the second clamping jig CJ2. In addition, as seen particularly in FIG. 5, the second clamping jig CJ2 is configured such that, in a state of being placed on the upper surface J2U of the second resin flow prevention jig J2, a lower surface of the second clamping jig CJ2 is separated from the upper surface M1U of the first member M1, and a surface of the second clamping jig CJ2, the surface facing the upright portion M2V of the second member M2, is separated from the upright portion M2V of the second member M2.
[0066] The notched portion CJ2R is formed in such a shape that an inner surface of the notched portion CJ2R is in close contact with at least the upper surface J2U and an end surface J2E in the longitudinal direction of the second member M2, of an exterior of the second resin flow prevention jig J2 at a central portion in the width direction of the second clamping jig CJ2 (see FIG. 5). As a result, a load can be applied to the second resin flow prevention jig J2 via the inner surface of the notched portion CJ2R of the second clamping jig CJ2 as will be described below.
[0067] Furthermore, as illustrated in FIGS. 6E and 7, the notched portion CJ2R is formed in a shape that accommodates the respective two arm portions CJ1A of the first clamping jig CJ1 downward in both ends in the width direction of the second clamping jig CJ2. In these portions, through holes CJ2H are formed in the second clamping jig CJ2 (see FIG. 7). Meanwhile, in these portions, screw holes CJ1H are formed in respective end surfaces in the longitudinal direction of the second member M2, of the two arm portions CJ1A of the first clamping jig CJ1 accommodated in the notched portion of the second clamping jig CJ2 (see FIG. 7).
[0068] Then, as illustrated in FIGS. 4, 6E, and 7, in a state where the end surfaces in the longitudinal direction of the two arm portions CJ1A of the first clamping jig CJ1 and the inner surface of the notched portion CJ2R of the second clamping jig CJ2, the inner surface facing the end surfaces, are in contact with each other, two bolts B are respectively inserted into the through holes CJ2H of the second clamping jig CJ2 and screwed into the screw holes CJ1H of the first clamping jig CJ1. Accordingly, the first clamping jig CJ1 and the second clamping jig CJ2 are brought into close contact with each other in the longitudinal direction of the second member M2. At this time, the first resin flow prevention jig J1 is pressed in a direction of the second resin flow prevention jig J2 by the first clamping jig CJ1 via the surface J1E, and the second resin flow prevention jig J2 is pressed in a direction of the first resin flow prevention jig J1 by the second clamping jig CJ2 via the surface J2E. As a result, the inner surface of the base portion J1B of the first resin flow prevention jig J1 is in close contact with the end surface in the longitudinal direction of the portion to be joined M2W of the second member M2, and a surface of the second resin flow prevention jig J2, the surface facing the second member M2, is in close contact with surfaces of the upright portion M2V and a curved portion M2R of the second member M2, in the longitudinal direction of the second member M2. As a result, even in a case where the thermoplastic resin becomes able to flow in the vicinity of a lower surface of the portion to be joined M2W of the second member M2 and in the vicinity of the upper surface of the first member M1 facing the lower surface, an outflow of the thermoplastic resin to the surroundings can be more reliably prevented than in the case of the method according to the first embodiment.
[0069] Note that, in the method according to the first embodiment, the downward loads are respectively applied to the first resin flow prevention jig J1 and the second resin flow prevention jig J2 by the load applying mechanisms independent of the load applying mechanism for applying the downward load to the second heat source H2. Meanwhile, in the method according to the second embodiment, downward loads <semantics>LCJ1<annotation encoding="application / x-tex">L_{CJ1}< / annotation>< / semantics> and <semantics>LCJ2<annotation encoding="application / x-tex">L_{CJ2}< / annotation>< / semantics> (see the arrows in FIG. 5) are respectively applied to the first clamping jig CJ1 and the second clamping jig CJ2 by the load applying mechanisms. Similarly to the method according to the first embodiment, a downward load <semantics>LH2<annotation encoding="application / x-tex">L_{H2}< / annotation>< / semantics> (see the arrow in FIG. 5) is applied to the second heat source H2.
[0070] Joining by the method according to the second embodiment of the present disclosure is performed by executing the following steps in sequence. (a) a step of placing the first member M1 on the upper surface H1U of the first heat source H1 (a first stage in an arrangement procedure of the members and the equipment; see FIG. 6A) (b) a step of placing the second member M2 on the upper surface M1U of the first member M1 and bringing the portion to be joined M2W into contact with the upper surface M1U of the first member M1 (the first stage in the arrangement procedure of the members and the equipment; see FIG. 6A) (c) a step of placing the heat-insulating material IS on the upper surface of the portion to be joined M2W of the second member M2 such that a surface of the heat-insulating material IS is in close contact with the surface of the second member M2 (a second stage in the arrangement procedure of the members and the equipment; see FIG. 6B) (d) a step of placing the second heat source H2 on the heat-insulating material IS and the upper surface of the portion to be joined M2W of the second member M2 so that the surface of the heat-insulating material IS is in close contact with an inner surface of a notched portion H2R (a second stage in the arrangement procedure of the members and the equipment; see FIG. 6B) (e) a step of controlling, by a controller, the unique load applying mechanism such that the downward load to be applied to the second heat source H2 (and the heat- insulating material IS) has desired magnitude (f) a step of placing the first resin flow prevention jig J1 and the second resin flow prevention jig J2 on the upper surface M1U of the first member M1 (a third stage in the arrangement procedure of the members and the equipment; see FIG. 6C) (F1) a step of placing the first clamping jig CJ1 on the upper surface J1U of the first resin flow prevention jig J1 (a fourth stage in the arrangement procedure of the members and the equipment; see FIG. 6D) (F2) a step of placing the second clamping jig CJ2 on the upper surface J2U of the second resin flow prevention jig J2 (a fifth stage in the arrangement procedure of the members and the equipment; see FIG. 6E) (F3) a step of bringing the first clamping jig CJ1 and the second clamping jig CJ2 into close contact with each other in the longitudinal direction of the second member M2 using the bolts B (g) a step of controlling, by the controller, the load applying mechanisms respectively unique to the first clamping jig CJ1 and the second clamping jig CJ2 such that the downward loads to be respectively applied to the first clamping jig CJ1 and the second clamping jig CJ2 have desired magnitude (h1) a step of heating the first heat source H1 to a first temperature T1 (controlling, by a temperature controller, ON / OFF of a heater embedded in the first heat source H1 such that the temperature measured by the temperature sensor embedded in the first heat source H1 becomes the first temperature T1) (h2) a step of heating the second heat source H2 to a second temperature T2 (controlling, by the temperature controller, ON / OFF of a heater embedded in the second heat source H2 such that the temperature measured by the temperature sensor embedded in the second heat source H2 becomes the second temperature T2) (i) a step of cooling the first member M1 and the second member M2 (by blowing air using a blower) after a predetermined retention time has elapsed since the temperature measured by the temperature sensor embedded in the first heat source H1 reached the first temperature T1 and the temperature measured by the temperature sensor embedded in the second heat source H2 reached the second temperature T2
[0071] In the joining by the above-described method, the first resin flow prevention jig J1 and the second resin flow prevention jig J2 surrounding the portion to be joined M2W of the second member M2 and the vicinity thereof are in close contact with the second member M2 by the first clamping jig CJ1 and the second clamping jig CJ2, and are further pressed against the upper surface M1U of the first member M1 by the downward loads applied by the load applying mechanisms. Therefore, even in a case where the thermoplastic resin becomes able to flow in the vicinity of the lower surface of the portion to be joined M2W of the second member M2 and in the vicinity of the upper surface of the first member M1 facing the lower surface, the thermoplastic resin can be reliably prevented from flowing out to the surroundings, and deformation of the members to be joined can be prevented.
[0072] Next, a joining method according to a third embodiment of the present disclosure will be described below with reference to FIG. 8.
[0073] FIG. 8 is a schematic cross-sectional view at a center in a width direction of members to be joined, illustrating a main part of an arrangement state of two members made of a material containing a thermoplastic resin and equipment for joining the two members at the time of performing joining by the method according to the third embodiment of the present disclosure.
[0074] The joining method according to the third embodiment of the present disclosure is obtained by adding a change to the joining method according to the first embodiment so that the joining method can be applied even in a case where a portion to be joined of a second member is very thick.
[0075] In the joining method according to the first embodiment, when the thickness of the portion to be joined of the second member exceeds a certain limit, there is a possibility of not enabling a temperature of a joint region between a first member and the second member to reach a weldable temperature of a thermoplastic resin in a case where a thermal output of a second heat source is not sufficient. In addition, even in a case where the second heat source has a sufficient thermal output, the temperature of at least a part of the portion to be joined (in the vicinity of the second heat source) may exceed a degradation temperature of the thermoplastic resin due to a temperature gradient generated in the portion to be joined. One reason for causing such a situation is that in the joining method according to the first embodiment, the temperature of the first heat source is set to be lower than the weldable temperature of the thermoplastic resin.
[0076] Therefore, in the joining method according to the third embodiment, a configuration of a first heat source is changed as compared with the joining method according to the first embodiment so as to enable the temperature of a joint region between a first member and the second member to reach the weldable temperature of the thermoplastic resin.
[0077] As illustrated in FIG. 8, a first heat source H1m includes a plurality of sections separated from each other by a heat-insulating material. More specifically, the first heat source H1m includes a high-temperature section H1mH located immediately below a portion to be joined M2mW of a second member M2m in a state where joining is performed, a heat-insulating section H1mIS disposed so as to surround the high-temperature section H1mH, and a low- temperature section H1mL disposed so as to surround the heat-insulating section H1mIS.
[0078] The high-temperature section H1mH is a rectangular parallelepiped section, and similarly to the first heat source H1 in the joining method according to the first embodiment, a heater and a temperature sensor (both not illustrated) are embedded in the high-temperature section H1mH.
[0079] In a plan view (not illustrated), a region occupied by the high-temperature section H1mH does not reach an outside of a region occupied by the portion to be joined M2mW of the second member M2m. In one embodiment, the region occupied by the high-temperature section H1mH is the same as the region occupied by the portion to be joined M2mW of the second member M2m. Preferably, the region occupied by the high-temperature section H1mH is smaller than the region occupied by the portion to be joined M2mW of the second member M2m. In this case, the former region is inside the latter region, and an outer edge of the former region and an outer edge of the latter region are separated from each other in any direction. By configuring the high-temperature section H1mH in a compact manner in this manner, a region of the members to be joined, the region being exposed to a high temperature equal to or higher than the weldable temperature of the thermoplastic resin, can be suppressed to be small, and thereby, flow of the thermoplastic resin can also be suppressed, as will be described below.
[0800] The heat-insulating section H1mIS is a hollow quadrangular prism-shaped section having an inner surface in close contact with each of four side surfaces of the rectangular parallelepiped high-temperature section H1mH, and includes a material having high heat-insulating properties.
[0081] The low-temperature section H1mL is a section having an inner surface in close contact with each of outer side surfaces of the heat-insulating section H1mIS, and similarly to the first heat source H1 in the joining method according to the first embodiment, a heater and a temperature sensor (both not illustrated) are embedded in the low-temperature section H1mL.
[0082] As described above, the portion to be joined M2mW of the second member M2m is significantly thicker than the portion to be joined M2W of the second member M2 in the joining method according to the first embodiment, and in order to cope with this difference in thickness, a slight change has been made to shapes of a heat-insulating material ISm and a second heat source H2m. That is, a height of the heat-insulating material ISm is lower than the height of the heat-insulating material IS in the joining method according to the first embodiment, and a height of a notched portion of the second heat source H2m is also lower than the height of the notched portion of the second heat source H2 in the joining method according to the first embodiment.
[0083] In the joining by the method according to the third embodiment, not only the second heat source H2m but also the high-temperature section H1mH of the first heat source H1m is set to a temperature (third temperature T3) higher than the weldable temperature and lower than the degradation temperature of the thermoplastic resin. As a result, even if the portion to be joined M2mW of the second member M2m is thick as described above, the joint region between a first member M1 and the second member M2m located between the two heat sources is sufficiently heated, and it is possible to cause the temperature to reach the weldable temperature of the thermoplastic resin. Note that the third temperature T3 may be equal to or different from a second temperature T2.
[0084] Meanwhile, the low-temperature section H1mL of the first heat source H1m has a temperature lower than the weldable temperature of the thermoplastic resin. As a result, the thermoplastic resin is prevented from being flowable at the portion of the first member M1 excluding the joint region.
[0085] That is, joining by the method according to the third embodiment of the present disclosure is performed by executing steps (a) to (i) of the above-described method according to the first embodiment in sequence, but step (h1) is changed as follows. (h1) a step of heating the high-temperature section H1mH of the first heat source H1m to the third temperature T3 (controlling ON / OFF of the heater embedded in the high- temperature section H1mH by a temperature controller such that the temperature measured by the temperature sensor embedded in the high-temperature section H1mH becomes the third temperature T3) and heating the low-temperature section H1mL of the first heat source H1m to a first temperature T1 (controlling ON / OFF of the heater embedded in the low-temperature section H1mL by the temperature controller such that the temperature measured by the temperature sensor embedded in the low-temperature section H1mL becomes the first temperature T1).
[0086] (Aspects of Present Disclosure) A method according to the first aspect of the present disclosure is for joining a first member and a second member both made of a material containing a thermoplastic resin, and the method includes, in sequence: (a) a step of placing the first member on an upper surface of a first heat source; (b) a step of placing the second member on an upper surface of the first member and bringing a portion to be joined of the second member into contact with the upper surface of the first member; (c) a step of placing a heat-insulating material on an upper surface of the portion to be joined of the second member such that a surface of the heat-insulating material is in close contact with a surface of the second member; (d) a step of placing a second heat source having a notched portion on the heat-insulating material and on the upper surface of the portion to be joined of the second member such that the surface of the heat-insulating material is in close contact with an inner surface of the notched portion; (e) a step of applying a downward load of desired magnitude to the second heat source and the heat-insulating material; (f) a step of placing a first resin flow prevention jig and a second resin flow prevention jig on the upper surface of the first member so as to surround the portion to be joined of the second member in cooperation with each other; (g) a step of applying a downward load of desired magnitude to the first resin flow prevention jig and the second resin flow prevention jig; (h) a step of heating the first heat source to a predetermined first temperature and heating the second heat source to a predetermined second temperature; and (i) a step of cooling the first member and the second member after a predetermined retention time has elapsed since a temperature of the first heat source reached the first temperature and a temperature of the second heat source reached the second temperature, in which the second temperature is higher than a weldable temperature of the thermoplastic resin and lower than a degradation temperature of the thermoplastic resin, and the first temperature is lower than the weldable temperature of the thermoplastic resin.
[0087] In a method according to the second aspect of the present disclosure, immediately after the step (f), (F) a step of placing a first clamping jig and a second clamping jig on the upper surface of the first member so as to respectively cover the first resin flow prevention jig and the second resin flow prevention jig from above, and bringing the first clamping jig and the second clamping jig into close contact with each other using a bolt is included, and the downward load is applied to each of the first resin flow prevention jig and the second resin flow prevention jig in the step (g) via the first clamping jig and the second clamping jig.
[8800] In a method according to the third aspect of the present disclosure, the first heat source includes a high- temperature section located immediately below the portion to be joined of the second member, a heat-insulating section disposed to surround the high-temperature section, and a low-temperature section disposed to surround the heat-insulating section, and in the step (h), the high- temperature section is heated to a temperature higher than weldable temperature of the thermoplastic resin and lower than the degradation temperature of the thermoplastic resin, while the low-temperature section is heated to a temperature lower than the weldable temperature of the thermoplastic resin. Explanation of Reference Signs
[0089] В Bolt CJ1 First clamping jig CJ2 Second clamping jig H1 and H1m First heat source H1U and H1mU Upper surface of first heat source Н2 Second heat source H2R Notched portion of second heat source IS Heat-insulating material <semantics>LH2<annotation encoding="application / x-tex">L_{H2}< / annotation>< / semantics>, <semantics>LJ1<annotation encoding="application / x-tex">L_{J1}< / annotation>< / semantics>, <semantics>LJ2<annotation encoding="application / x-tex">L_{J2}< / annotation>< / semantics>, <semantics>LCJ1<annotation encoding="application / x-tex">L_{CJ1}< / annotation>< / semantics>, and <semantics>LCJ2<annotation encoding="application / x-tex">L_{CJ2}< / annotation>< / semantics> Load J1 First resin flow prevention jig J2 Second resin flow prevention jig M1 First member M1U Upper surface of first member M2 Second member M2W Portion to be joined of second member T1 First temperature Т2 Second temperature Th Degradation temperature of thermoplastic resin Tm Weldable temperature of thermoplastic resin t Retention time
Claims
2. The method according to claim 1, comprising: immediately after the step (f), (F) a step of placing a first clamping jig and a second clamping jig on the upper surface of the first member so as to respectively cover the first resin flow prevention jig and the second resin flow prevention jig from above, and bringing the first clamping jig and the second clamping jig into close contact with each other using a bolt, wherein the downward load is applied to each of the first resin flow prevention jig and the second resin flow prevention jig in the step (g) via the first clamping jig and the second clamping jig.
3. The method according to claim 1, wherein the first heat source includes a high-temperature section located immediately below the portion to be joined of the second member, a heat-insulating section disposed to surround the high-temperature section, and a low-temperature section disposed to surround the heat-insulating section, and in the step (h), the high-temperature section is heated to a temperature higher than weldable temperature of the thermoplastic resin and lower than the degradation temperature of the thermoplastic resin, while the low- 5 temperature section is heated to a temperature lower than the weldable temperature of the thermoplastic resin.