Electrical connection components

Abstract

To provide an electric connection member where a seal material is arranged between a terminal and a housing, which can maintain high sealability, even in a situation that the seal material is brought into contact with lubricating oil.SOLUTION: An electric connection member 1 has a terminal 2, a housing 3 holding the terminal 2, and a seal material 4 arranged between the terminal 2 and the housing 3, wherein the housing 3 contains at least one of a polyester-based resin and a polyamide-based resin, and the seal material 4 contains a thermoplastic polymer, can be dissolved or swollen in both hexafluoroisopropanol and m-cresol, and has a mass change rate when being immersed in lubricating oil at 100°C for 8 hours of less than 20%.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an electrical connection member.

Background Art

[0002] In an electrical connection member in which terminals are held in a resin housing such as a terminal block, water may enter the interior of the device to which the electrical connection member is attached through the gap between the housing and the terminals, which may cause problems. In such cases, it is required to impart sealing properties to the electrical connection member and suppress the passage of liquid at the location between the housing and the terminals. As a method of imparting sealing properties to the electrical connection member, there are methods of devising the constituent material of the housing and the structure of the terminals (Patent Document 1), a method of filling the housing with a potting material (Patent Document 2), a method of disposing a sealing material between the housing and the terminals and sealing (Patent Documents 3 and 4), and the like.

[0003] Among the above, according to the method using a sealing material, sealing properties can be imparted to the electrical connection member without designing the terminals with a special structure or providing a portion for accommodating a potting resin in the housing. As the sealing material, in Patent Document 3, a rubber-based adhesive is used. The rubber-based adhesive is cured by vulcanization.Otherwise, a thermosetting polymer may be used as the sealing material. On the other hand, in Patent Document 4, as the sealing material, a thermoplastic elastomer resin composition containing an acid-modified styrene-based elastomer, syndiotactic polystyrene, and hydrogenated dicyclopentadiene in a predetermined ratio is used.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

[0005] As described above, placing a sealing material between the housing and the terminals in an electrical connection component is effective in preventing water from entering the inside of the device in which the electrical connection component is installed. At the same time, if lubricating oil is used inside the device, the sealing material will also provide a sealing effect against the lubricating oil, and it is expected that this will prevent the lubricating oil from leaking out of the device through the gap between the housing and the terminals. For example, in an automobile driven by a motor, a terminal block is provided on the motor, and power is transmitted from the inverter to the motor via this terminal block. In this type of terminal block, a sealing material may be provided between the housing and the terminals (busbars) to prevent moisture such as rainwater from entering the motor and to prevent leakage of lubricating oil filled inside the motor.

[0006] When a terminal block is installed on a device containing lubricating oil, such as a motor, the sealing material will be in contact with the lubricating oil inside the motor. In such cases where the sealing material is placed in a location that comes into contact with the lubricating oil, it is desirable that the sealing material exhibits high sealing performance even when in contact with the lubricating oil. However, even a sealing material that exhibits high sealing performance when not in contact with the lubricating oil does not necessarily function to exhibit high sealing performance when in contact with the lubricating oil.

[0007] In view of the above, the objective is to provide an electrical connection member in which a sealing material is placed between the terminal and the housing, and which can maintain high sealing performance even when the sealing material is in contact with lubricating oil. [Means for solving the problem]

[0008] The electrical connection member of this disclosure comprises a terminal, a housing for holding the terminal, and a sealing material disposed between the terminal and the housing, wherein the housing comprises at least one of a polyester resin and a polyamide resin, and the sealing material comprises a thermoplastic polymer, is soluble or swellable in both hexafluoroisopropanol and m-cresol, and has a mass change rate of less than 20% when immersed in lubricating oil at 100°C for 8 hours. [Effects of the Invention]

[0009] The electrical connection member according to this disclosure is an electrical connection member in which a sealing material is placed between a terminal and a housing, and is an electrical connection member that can maintain high sealing performance even when the sealing material is in contact with lubricating oil. [Brief explanation of the drawing]

[0010] [Figure 1] Figures 1A and 1B are a side view and a cross-sectional view, respectively, showing a terminal block as an electrical connection member according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a side view showing an adhesiveness test specimen. [Figure 3] Figures 3A and 3B are perspective and cross-sectional views, respectively, of a sealing test specimen. Figure 3C is a schematic diagram illustrating the method for conducting the sealing test. [Modes for carrying out the invention]

[0011] [Description of Embodiments of this Disclosure] First, embodiments of the present disclosure will be described. The electrical connection member of the present disclosure has the following configuration.

[0012] [1] An electrical connection member of the present disclosure comprises a terminal, a housing for holding the terminal, and a sealing material disposed between the terminal and the housing, wherein the housing comprises at least one of a polyester resin and a polyamide resin, and the sealing material comprises a thermoplastic polymer, is soluble or swellable in both hexafluoroisopropanol and m-cresol, and has a mass change rate of less than 20% when immersed in lubricating oil at 100°C for 8 hours.

[0013] In the electrical connection member of this disclosure having the above configuration, the sealing material placed between the housing and the terminal contains a thermoplastic polymer, and therefore tends to exhibit higher adhesion to the housing compared to cases where the sealing material is composed of a polymer that hardens by vulcanization or a thermosetting polymer. This is because if the sealing material containing a thermoplastic polymer is placed on the surface of the terminal and the housing is formed by molding or the like on the area including the surface of the sealing material while heating as appropriate, the sealing material will soften or melt due to the heat, and after cooling, it will adhere strongly not only to the terminal but also to the housing. Furthermore, in the electrical connection member of this disclosure, the sealing material is soluble or swellable in both hexafluoroisopropanol and m-cresol, and therefore exhibits particularly high adhesion to the housing. This is because the polyester resin and polyamide resin that constitute the housing are also materials that are soluble or swellable in hexafluoroisopropanol and m-cresol, and the sealing material has high compatibility with the housing's constituent materials. Thus, the high adhesion of the sealing material to the housing provides high sealing performance in the electrical connection components, effectively suppressing the permeation of water and lubricating oil through the area between the housing and the terminals. Furthermore, the high adhesion of the sealing material to the housing allows it to maintain high sealing performance even when the sealing material is heated to high temperatures.

[0014] Furthermore, the sealing material constituting the electrical connection member of this disclosure exhibits a mass change rate of less than 20% when immersed in lubricating oil at 100°C for 8 hours. Therefore, even when in contact with high-temperature lubricating oil, it is less likely to undergo changes such as dissolution or swelling. Consequently, even when the electrical connection member is used in an environment where the sealing material comes into contact with lubricating oil, the high adhesion that the sealing material exhibits to the housing, as described above, is unlikely to be impaired by the effects of the lubricating oil, and a state of high sealing performance is maintained. Thus, the electrical connection member of this disclosure can be suitably used as a component of equipment containing lubricating oil or equipment used in an environment where lubricating oil is present.

[0015] [2] In the embodiment of [1] above, it is preferable that the melting point of the sealing material is 150°C or higher. Then, even when the electrical connection member is used in an environment where the temperature exceeds 150°C, a decrease in sealing performance due to deterioration that occurs at or near the melting point of the sealing material, such as dissolution of the sealing material, can be avoided, and high sealing performance can be maintained. In motors for automobiles, large currents are supplied, so the terminal block tends to heat up to high temperatures, but by maintaining high sealing performance even at high temperatures, the electrical connection member of this disclosure can be suitably used even in high-temperature environments.

[0016] [3] In the embodiments of [1] or [2] above, the sealing material may include a thermoplastic elastomer as the thermoplastic polymer. This makes it easier to maintain a high sealing performance because the sealing material is flexible, and the electrical connection member is less susceptible to deterioration due to thermal shock even when used in environments with large temperature fluctuations.

[0017] [4] In any one embodiment of [1] to [3] above, the sealing material may include at least one of polyurethane resin, polyester resin, and polyamide resin as the thermoplastic polymer. These resins exhibit high adhesion to housings containing at least one of polyester resin and polyamide resin, and are less susceptible to changes caused by lubricating oil, making them suitable for use as constituent materials for the sealing material.

[0018] [5] In any one of the aspects [1] to [4] above, the housing may include at least one of polybutylene terephthalate, nylon 6T, and nylon 9T. These resin types have high mechanical strength and heat resistance and can be suitably used to form the housing.

[0019] [6] In any one of the aspects [1] to [5] above, the electrical connection member may be configured as a terminal block of a motor. The terminal block of the motor is a member that comes into contact with the lubricating oil filled in the motor and is likely to become hot when the motor is energized. However, the electrical connection member of the present disclosure can maintain high sealing performance even in an environment where it comes into contact with high-temperature lubricating oil, and thus can be suitably used as a terminal block of a motor.

[0020] [Details of Embodiments of the Present Disclosure] Hereinafter, an electrical connection member according to an embodiment of the present disclosure will be described in detail with reference to the drawings. Hereinafter, unless otherwise specified, the values of various characteristics are measured at room temperature in the atmosphere. Also, in this specification, polymers include polymers with relatively low degrees of polymerization such as oligomers.

[0021] <Configuration of Electrical Connection Member> The electrical connection member of the present disclosure has a terminal and a housing that holds the terminal, and a sealing material is further disposed between the terminal and the housing. The electrical connection member is not particularly limited as long as it has a terminal and a housing and can dispose a sealing material between the terminal and the housing, and examples thereof include a terminal block, a connector, and the like. Hereinafter, a terminal block will be described as a preferred example of the electrical connection member.

[0022] Figures 1A and 1B show a schematic of a terminal block 1 as an electrical connection member according to one embodiment of the present disclosure. Figure 1A is a side view, and Figure 1B is a cross-sectional view showing section AA in Figure 1A. The terminal block 1 has one or more (in this case, three) terminals (busbars) 2 and a housing 3. A sealing material 4 is placed between each terminal 2 and the housing 3. In addition, a rubber ring 5 is optionally placed on the outer circumference of the housing 3.

[0023] The terminal (busbar) 2 is constructed as a rod-shaped or plate-shaped member made of metal. In the illustrated form, the terminal 2 is constructed as a plate piece having connection holes for connecting electric wires at both ends. The constituent material of the terminal 2 is not particularly limited. Metal materials such as copper or copper alloys, aluminum or aluminum alloys, iron or iron alloys, or materials in which a coating layer made of another metal, such as a plating layer made of tin or a tin alloy, is formed on the surface of these metal materials can be suitably used. A material in which a plating layer made of tin or a tin alloy is formed on the surface of a base material made of copper or a copper alloy can be particularly suitably used.

[0024] The housing 3 surrounds the outer circumference of the terminal 2 in at least a portion of its area and holds the terminal 2. In the illustrated configuration, the housing 3 integrally comprises a block-shaped holding portion 32 and a flat flange portion 31. The holding portion 32 is the part that holds the terminal 2, and each terminal 2 is embedded in the holding portion 32 of the housing 3 in the middle of its longitudinal direction. The holding portion 32 holds the three terminals 2 together, arranged parallel to each other with a distance between them. The flange portion 31 functions as a mounting portion when attaching the terminal block 1 to a device or the like.

[0025] Housing 3 is composed of a material containing at least one of a polyester resin and a polyamide resin. Polyester resins and polyamide resins are suitable as constituent materials for housing 3 because they have high mechanical strength and high heat resistance. Preferably, 50% by mass or more, more preferably 90% by mass or more, and most preferably the entire amount of the polymer material constituting housing 3 is composed of at least one of a polyester resin and a polyamide resin. Polybutylene terephthalate (PBT) can be suitably used as the polyester resin. Suitable polyamide resins include nylon 6T (PA6T), nylon 9T (PA9T), nylon 66 (PA66), nylon 610 (PA610), and nylon 612 (PA612). In addition to polymer materials such as polyester resins and polyamide resins, the constituent materials of housing 3 may also contain additives such as antioxidants as appropriate.

[0026] The sealing material 4 is made of a material containing a thermoplastic polymer. The sealing material 4 is positioned between the terminal 2 and the housing 3, sealing the space between the terminal 2 and the housing 3. The sealing material 4 may be provided over the entire area between the terminal 2 and the housing 3, or, as shown in the illustrated configuration, it may be provided only in a portion of the area. In the illustrated configuration, the sealing material 4 is positioned around the entire circumference of the terminal 2 (see Figure 3B) in a portion of the area along the longitudinal direction of the terminal 2 within the area where the terminal 2 is embedded in the housing 3. In this way, the sealing material 4 is positioned to seal the space between the terminal 2 and the housing 3, thereby blocking communication between the space where one end of the terminal 2 is located (outer space S1 in the figure) and the space where the other end is located (inner space S2 in the figure).

[0027] The sealing material 4 seals the space between the terminal 2 and the housing 3, thereby preventing liquids, including water, from moving through the gap between the terminal 2 and the housing 3 and between the outer space S1 and the inner space S2 of the terminal block 1. In other words, the sealing material 4 provides sealing to the terminal block 1. The sealing material 4 exhibits high sealing performance because its constituent materials have predetermined properties, which will be explained in detail later.

[0028] The rubber ring 5 is an O-ring shaped member made of an elastic material such as rubber, and is installed on the outer circumference of the housing 3. In the illustrated configuration, the rubber ring 5 is installed in the holding portion 32 of the housing 3, near the boundary with the flange portion 31. When the terminal block 1 is attached to a device, the rubber ring 5 plays a role in preventing liquids such as water from moving between the outer space S1 and the inner space S2 through the gap between the wall surface of the device and the flange portion 31.

[0029] Terminal block 1 can be attached to various devices and used as a component to form an electrical connection between an outer space S1 and an inner space S2. An opening can be provided in the device to which terminal block 1 can be attached. The portion of terminal block 1 corresponding to the inner space S2 is inserted into the opening, and terminal block 1 is fixed to the device with the flange portion 31. The portion of terminal block 1 corresponding to the outer space S1 protrudes to the outside of the device. Because terminal block 1 has sealing properties, when attached to the device in this manner, the movement of liquids between the inside and outside of the device via terminal block 1 is unlikely to occur. In other words, the movement of liquids through the gap between terminal 2 and housing 3 is suppressed by the sealing material 4, and the movement of liquids through the gap between housing 3 and the device wall is suppressed by the rubber ring 5. In particular, the intrusion of moisture such as rainwater from the outside of the device into the inside of the device is effectively suppressed. Furthermore, it is also effective in suppressing the phenomenon of liquids such as lubricating oil placed inside the device leaking to the outside of the device.

[0030] The type of device to which terminal block 1 is attached is not particularly limited, but as will be explained later, since the sealing material 4 is made of a material that can maintain high sealing performance even when in contact with lubricating oil, terminal block 1 can be suitably applied to devices that use lubricating oil and where water ingress is undesirable, from the viewpoint of effectively utilizing these properties. Examples of such devices include motors, especially motors for automobiles. In automobile motors, it is necessary to suppress the ingress of moisture from the outdoor environment, such as rainwater, so terminal block 1 is required to have high waterproofness. In addition, the inside of the motor is usually filled with lubricating oil, and sealing performance against the lubricating oil is also required.

[0031] The method for manufacturing the terminal block 1 is not particularly limited, and either a method of assembling independently formed components or a method of integral molding may be used. However, integral molding is preferably applied. When integral molding is performed, first, a sealing material 4 is placed at a predetermined position on the outer circumference of the surface of the terminal 2. At this time, the constituent material of the sealing material 4 may be heated and melted before being placed at the predetermined location. Methods such as mold molding using a mold, coating, or dripping can be used to place the sealing material 4 at the predetermined location. After placing the sealing material 4 at the predetermined location, the sealing material 4 is heated to a temperature above its melting point or softening temperature, and a housing 3 is formed in a predetermined area including the area surrounding the sealing material 4. The housing 3 may be formed by mold molding using a mold. A rubber ring 5 may be attached to the outer circumference of the formed housing 3 as appropriate.

[0032] In the above manufacturing method, when the sealing material 4 is placed on the surface of the metal terminal 2, the sealing material 4 is firmly adhered to the surface of the terminal 2 by contacting the surface of the metal material with the constituent material of the sealing material 4, which is in a molten or softened state. Furthermore, when forming the housing 3, the constituent material of the housing 3 is formed on the surface of the sealing material 4 while the sealing material 4 is heated to a temperature above its melting point or softening temperature, causing fusion between the sealing material 4 and the housing 3, and thus the sealing material 4 is adhered to the housing 3. Heating the sealing material 4 to a temperature above its melting point or softening temperature can be done by the heat contained in the constituent material of the housing 3 during the molding of the housing 3, or by separately heating the sealing material 4 before forming the housing 3. Preferably, from the viewpoint of obtaining high adhesive strength between the sealing material 4 and the housing 3, the heating temperature should be set so that the sealing material 4 is heated to a temperature above its melting point and melts.

[0033] <Materials that make up the sealing material> Next, the constituent materials of the sealing material 4 used in the terminal block (electrical connection member) 1 according to this embodiment will be described.

[0034] As described above, the sealing material 4 used in this embodiment is composed of a thermoplastic polymer. Because the sealing material 4 contains a thermoplastic polymer, the entire constituent material of the sealing material 4 exhibits thermoplastic properties. Because the sealing material 4 is composed of a thermoplastic material, high adhesive strength can be obtained between the sealing material 4 and the terminal 2 and housing 3. In particular, the adhesion between the sealing material 4 and the housing 3 is easier to obtain than when a polymer that hardens by vulcanization or a thermosetting polymer is used as the sealing material 4 instead of a thermoplastic polymer. When a polymer that hardens by vulcanization or a thermosetting polymer is used, the housing 3 is formed on the surface of the sealing material which is already hardened, making it difficult to form a strong bond on a microscopic scale. In contrast, when a thermoplastic polymer is used, as described above regarding the manufacturing method of the terminal block 1, the sealing material 4 is placed on the surface of the terminal 2 and then melted or softened by heating before the housing 3 is formed. This causes fusion between the constituent materials of the sealing material 4 and the housing 3, and close contact is formed due to microscopic interaction. From the viewpoint of enhancing the effect of improving adhesion, it is preferable that 50% by mass or more, more preferably 90% by mass or more, and most preferably the entire amount, of the polymer material constituting the sealant 4 is composed of a thermoplastic polymer. Furthermore, it is preferable that the various properties described below as the properties of the entire constituent material of the sealant 4 are also possessed as properties of the thermoplastic polymer constituting the sealant 4 alone.

[0035] Furthermore, the sealing material 4 used in this embodiment exhibits particularly high adhesion to the housing 3 due to its predetermined dissolution and swelling properties. Specifically, the sealing material 4 is soluble or swellable in both hexafluoroisopropanol (HFIP) and m-cresol. Here, the solubility and swelling properties in HFIP and m-cresol serve as indicators of the compatibility between the sealing material 4 and the polymer material constituting the housing 3. Among various organic solvents, HFIP has a relatively small solubility parameter (SP value), while m-cresol has a large SP value. However, the polyester resin and polyamide resin, which are materials constituting the housing 3, readily dissolve or swell in both HFIP and m-cresol. In fact, in the examples, it has been confirmed that PBT and PA6T, PA9T are soluble or swellable in both HFIP and m-cresol. Specifically, it has been confirmed that PBT is swellable in both solvents, and PA6T and P9T are soluble in both solvents. The fact that two different materials, namely the constituent materials of the sealant 4 and the constituent materials of the housing 3, are soluble or swollen in the same solvent indicates high compatibility between the two materials, and that when the two materials are brought into contact in a flowable state, they mix with each other at the molecular level. In other words, it indicates that high adhesion can be obtained at the fusion interface. In this embodiment, because the constituent materials of the sealant 4 are soluble or swollen in both HFIP and m-cresol, the sealant 4 exhibits high adhesion to the housing 3, which is composed of materials that are also soluble or swollen in those solvents. In particular, if at least one, preferably both, of the constituent materials of the sealant 4 and the housing 3 are soluble in both HFIP and m-cresol, particularly high compatibility and adhesion can be obtained between the sealant 4 and the housing 3. As the housing 3, polyamide resins such as PA6T and PA9T, which are soluble in both HFIP and m-cresol, can be used particularly suitably.

[0036] Here, HFIP and m-cresol are used as solvents that serve as indicators of compatibility between the sealant 4 and the housing 3 because their SP values ​​are somewhat far apart, and because both are solvents with intramolecular polarization, making it easy to accurately evaluate their compatibility with polymers that have polarization, such as polyester resins and polyamide resins. In this specification, a material being soluble in a solvent means that when pellets of that material are immersed in the solvent, the pellets become uniformly mixed with the solvent to a level that is not visible to the naked eye. Furthermore, a material being swollen in a solvent means that when pellets of that material are immersed in the solvent, the pellets undergo an increase in mass. An increase in mass refers, for example, to a state where the mass exceeds 1.1 times compared to before immersion in the solvent. As for the conditions for determining dissolution and swelling, as demonstrated in later examples, an example can be given where 0.3 g of sealant 4 is mixed with 10 ml of solvent and left to stand at room temperature for one week.

[0037] The sealant 4 used in this embodiment has high oil resistance in addition to the above-mentioned dissolution and swelling characteristics. Specifically, the sealant 4 has a mass change rate (hereinafter referred to as the oil-resistant mass change rate) of less than 20% when immersed in lubricating oil at 100°C for 8 hours. Here, the oil-resistant mass change rate of the sealant 4 is expressed as an absolute value of the amount of change in mass due to immersion, i.e., the decrease or increase, based on the mass before immersion in lubricating oil. An oil-resistant mass change rate of less than 20% indicates that even when the sealant 4 comes into contact with high-temperature lubricating oil, it is less likely to undergo changes such as a decrease in mass due to dissolution or an increase in mass due to swelling. In other words, the sealant 4 has high oil resistance and is less likely to experience a decrease in adhesion due to the effect of lubricating oil or permeation of lubricating oil even when in contact with high-temperature lubricating oil. More preferably, the oil-resistant mass change rate is 10% or less, and even more preferably 7% or less. There is no particular lower limit set for the oil-resistant mass change rate, but it is generally 1% or more. The specific type of lubricant used to evaluate the oil resistance mass change rate is not particularly limited, but it is preferable to use a lubricant that may come into contact with the sealing material 4, such as the lubricant used in the device to which the terminal block 1 is attached. For example, it is preferable to use ATF (Automatic Transmission Fluid) as the lubricant. ATF is sometimes used to fill motors in automobiles.

[0038] As described above, because the sealing material 4 contains a thermoplastic polymer and is soluble or swollen in HFIP and m-cresol, it exhibits high adhesion not only to the terminals 2 but also to the housing 3. Therefore, in the terminal block 1, the movement of liquids such as water between the outer space S1 and the inner space S2 through the gap between the housing 3 and the terminals 2 is strongly suppressed, and the terminal block 1 is given high sealing performance. As a result, in the device to which the terminal block 1 is attached, the intrusion of moisture such as rainwater from the outside through the area between the housing 3 and the terminals 2 is effectively suppressed. High effectiveness is also obtained in suppressing the leakage of liquids inside the device, such as lubricating oil, to the outside of the device. Furthermore, because the sealing material 4 exhibits high adhesion to the terminals 2 and the housing 3, it can maintain high sealing performance even in environments where the sealing material 4 is exposed to high temperatures. Moreover, because the oil resistance mass change rate of the sealing material 4 is kept below 20%, the state in which the sealing material 4 adheres strongly to the terminals 2 and the housing 3 and exhibits high sealing performance can be maintained even in environments in contact with high-temperature lubricating oil. Because the sealing material 4 possesses these properties, the terminal block 1 according to this embodiment is provided with high sealing performance by the sealing material 4, and maintains that sealing performance even in high-temperature environments or environments in contact with lubricating oil.

[0039] As described above, the sealing material 4 is soluble or swollen in HFIP and m-cresol, exhibiting high adhesion to the housing 3, and achieving an adhesive strength of, for example, 0.5 MPa or more between it and the housing 3. More preferably, the adhesive strength is 3 MPa or more. There is no particular upper limit to the adhesive strength, but it is generally 10 MPa or less. The adhesive strength of the sealing material 4 to the housing 3 can be evaluated as shear adhesive strength by performing a tensile shear test on an adhesive test specimen in which the sealing material 4 is sandwiched between a plate-shaped component of the housing 3 and a copper plate and bonded, as shown in later examples.

[0040] Furthermore, it is preferable that the sealing material 4 has a melting point of 150°C or higher. This results in the sealing material 4 having high heat resistance, making it less susceptible to deterioration of adhesion due to elution or modification even when placed in a high-temperature environment. In particular, even if the sealing material 4 is hydrolyzable, hydrolysis that may occur when heated to or near its melting point while humidified, and the resulting deterioration of the sealing material 4, can be suppressed. Thus, having a high melting point for the sealing material 4 makes the terminal block 1 particularly suitable for applications that are subjected to heating. For example, in automobile motors, a large current is supplied through the terminal block 1, so the terminal block 1 tends to become hot. It is more preferable that the melting point of the sealing material 4 is 155°C or higher. There is no particular upper limit set for the melting point of the sealing material 4, but from the viewpoint of ease of molding and bonding by heating, it is preferable that it be approximately 200°C or lower.

[0041] The specific materials constituting the sealing material 4 are not particularly limited, but it is preferable that it contains a thermoplastic elastomer as a thermoplastic polymer. Because thermoplastic elastomers are flexible, they can effectively mitigate thermal shock. Therefore, the sealing material 4 is less susceptible to deterioration due to thermal shock, and even when the terminal block 1 is used in an environment subject to large temperature changes, such as inside an automobile, the sealing performance of the sealing material 4 can be maintained at a high level. Elastomers are generally polymers having a shear modulus of approximately 1 MPa to 200 MPa, and in this embodiment, a thermoplastic elastomer having a shear modulus of approximately that magnitude may be used. Particularly preferable is the use of a thermoplastic elastomer with a shear modulus of 150 MPa or less, and more preferably 100 MPa or less.

[0042] Furthermore, as the polymer species of the thermoplastic polymer constituting the sealing material 4, at least one of polyurethane resins, polyester resins, and polyamide resins can be suitably used. These resins tend to exhibit high adhesion to the metal terminal 2 and the housing 3 containing polyester resin or polyamide resin, and also have high oil resistance. Here, the above resins may also be elastomers, and it is particularly preferable that the sealing material 4 contains at least one of polyurethane elastomers, polyester elastomers, and polyamide elastomers as the thermoplastic polymer.

[0043] The sealing material 4 may contain various additives in addition to polymer materials such as thermoplastic polymers. A suitable example of an additive is a silane coupling agent. Since the sealing material 4 contains a thermoplastic polymer, it exhibits high adhesion to the terminal 2 when placed on the surface of the terminal 2 in a molten state. However, by adding a silane coupling agent to the sealing material 4, the adhesion to the terminal 2 can be further enhanced. This is because the silane coupling agent forms a stable chemical bond with the metal atoms on the metal surface. While tackifiers made of terpene phenol resins and the like also have the function of improving adhesion between the sealing material 4 and the metal surface, many of them have low oil resistance. From the viewpoint of minimizing the impact on the oil resistance of the sealing material 4, it is preferable to use a silane coupling agent, which is a substance with high oil resistance, rather than a tackifier. Other additives besides silane coupling agents include coloring pigments, viscosity modifiers, antioxidants, inorganic fillers, preservatives, and dispersants. [Examples]

[0044] Examples are shown below. Here, the relationship between the properties of the sealing material and its sealing performance was investigated. In these examples, unless otherwise specified, the properties were evaluated at room temperature in air.

[0045] [Sample preparation] The following materials were prepared as sealing agents. • Sealant A1: Polyurethane resin - BASF "Elastran 1198A" • Sealant A2: Polyester resin - "ESTERAR E-D42N" manufactured by Aron Kasei Co., Ltd. • Sealant A3: Polyamide resin - "VG TPA-2181" manufactured by Tsukuno Foods Industry Co., Ltd. • Sealant B1: Polystyrene resin - "Arbus VF-A90NT" manufactured by Aron Kasei Co., Ltd. • Sealing material B2: Polyester resin - "Pensel D-125" manufactured by Arakawa Chemical Industries, Ltd. • Sealant B3: Polyolefin resin - Mitsui Chemicals, Inc. "Milastomer A970B" • Sealant B4: Polyvinyl chloride resin - Kraiburg TPE's "HIPEX HX71DZ" All of the above materials are thermoplastic, and all except sealant B2 are thermoplastic elastomers. Furthermore, the shear modulus of each material is 100 MPa or less.

[0046] Furthermore, using each of the above-mentioned sealing materials, adhesive test specimens for adhesion testing and sealing test specimens for sealing testing were prepared. For the adhesive test specimens, the structure shown in Figure 2 was prepared. That is, an adhesive test specimen P was prepared in which a sheet body 4a made of the sealing material was sandwiched between a copper plate 2a and a resin plate 3a, and bonded to the copper plate 2a and the resin plate 3a on both sides. To prepare the adhesive test specimen P, first, each sealing material was formed into a sheet with a thickness of 0.5 mm by hot pressing, and then cut into 10 mm x 10 mm pieces. Next, the cut sheet body 4a was placed on the copper plate 2a (C1100 material) and bonded to the copper plate 2a by heating at 200°C for 20 minutes. Furthermore, the copper plate 2a to which the sheet body 4a was bonded was set in the mold, and PA6T (DuPont's "HTN 54G35EF BK420"), which is a component material of the housing, was molded into a plate shape onto the surface of the sheet body 4a to form a resin plate 3a. The molding was performed under the following conditions: nozzle temperature 320°C, mold temperature 140°C, injection speed 60 mm / s, and holding pressure 40 MPa.

[0047] For the sealing performance test specimen, a structure as shown in Figures 3A and 3B was prepared. Figure 3A is a perspective view of the sealing performance test specimen P', and Figure 3B is a cross-sectional view showing the BB section in Figure 3A. The sealing performance test specimen P' is modeled after a terminal block, with a sealing material 4b placed in a portion of the outer circumference of the model terminal 2b, and the housing 3b is formed including the portion covering the sealing material 4b. In preparing this sealing performance test specimen P', a copper piece was prepared as the model terminal 2b. The size of the model terminal 2b was 12.0 mm × 80.0 mm × 1.6 mm. Along the longitudinal direction of this model terminal 2b, the sealing material 4b was bonded to a portion of the outer circumference so as to cover the entire outer circumference. At this time, the placement and bonding of the sealing material 4b to the predetermined position was performed by molding at a temperature 30°C higher than the melting point of each sealing material. The width of the area covered by the sealant 4b (the dimension along the longitudinal direction of the model terminal 2b) was set to 5 mm, and the thickness of the sealant 4b layer was set to 1 mm. Furthermore, a housing 3b was molded around the outer circumference of the model terminal 2b, including the area covering the entire sealant 4b. The materials and conditions used when molding the housing 3b were the same as those used when forming the resin plate 3a in the adhesiveness test specimen P described above.

[0048] [Evaluation of characteristics] The properties of each of the sealants, A1-A3 and B1-B4, were evaluated through the following tests.

[0049] (1) Dissolution and swelling properties Dissolution and swelling tests were conducted to evaluate the dissolution and swelling characteristics of each sealant, that is, whether each sealant dissolved or swelled in the solvent. Specifically, 10 ml of HFIP or m-cresol was taken into a glass container as the solvent, and 0.3 g of each sealant, formed into pellets, was mixed in it. After the mixture was left to stand at room temperature for one week, it was determined by visual inspection whether it had dissolved or not. In this case, if the sealant pellets dissolved uniformly in the solvent and formed a uniform mixture to the point where the pellets could not be identified by visual inspection, it was determined that the sealant had dissolved. On the other hand, if the shape of the pellets could be identified by visual inspection, it was determined that the sealant had not dissolved. If dissolution did not occur, the mass change was further determined from the mass before and after immersion in the solvent, and if the mass after immersion exceeded 1.1 times the mass before immersion, it was determined that the sealant had swelled. Samples that dissolved were classified as "A", samples that did not dissolve but swelled were classified as "B", and samples that neither dissolved nor swelled were classified as "C". In fact, none of the sealants tested were rated as "B".

[0050] The above dissolution and swelling tests were performed on each sealing material, and the following materials that make up the housing were also subjected to dissolution and swelling tests in the same manner as above. It was confirmed that all materials showed solubility or swelling in both HFIP and m-cresol. • PBT: Polyplastics "CG7030" - Dissolution and swelling properties: B • PA6T: DuPont "HTN 54G35EF BK420" - Dissolution and swelling properties: A • PA9T: Kuraray Co., Ltd. "GENESTAR G1300H" - Dissolution and swelling properties: A

[0051] (2) Change rate of oil-resistant mass Two grams of each sealant were taken, their mass measured, and placed in a container. The entire container was then immersed in lubricating oil (Shell Lubricants Japan ATF "CVTF S-NS-3"). This was left at 100°C for eight hours. After that, the sealant was removed from the lubricating oil, the surface oil was wiped off, and the mass of the sealant was measured. The change in mass was then calculated relative to the mass of the sealant before immersion and was defined as the oil resistance mass change rate. The oil resistance mass change rate represents the rate of change in mass regardless of the direction of change. In this example, changes in the direction of mass increase are recorded as positive values, and changes in the direction of mass decrease are recorded as negative values.

[0052] (3) Melting point The melting point of each sealing material was measured using the Differential Scanning Calorimetry (DSC) method. The temperature range for the measurements was 23°C to 200°C, and the heating rate was 100°C / min.

[0053] (4) Adhesive strength The adhesive strength of the sealing material was measured by a tensile shear test using the adhesive test specimen P prepared as described above. In this test, the portions of the copper plate 2a and the resin plate 3a that were not bonded to the sheet body 4a made of the sealing material were gripped and set in a tensile testing machine, and a tensile load in the shear direction was applied parallel to the plate surface, as shown by the arrows in Figure 2. In the tensile shear test, fracture occurred at the interface between the sheet body 4a and the copper plate 2a, or at the interface between the sheet body 4a and the resin plate 3b. For fractures that occurred at the interface between the sheet body 4a and the resin plate 3a, the load at the time of fracture was recorded as the adhesive strength of the sealing material to the resin plate 3a. For fractures that occurred at the interface between the sheet body 4a and the copper plate 2a, the adhesive strength of the sealing material to the resin plate 3a was recorded as being higher than the load at the time of fracture (the load at the time of fracture is shown in Table 1 with the ">" symbol). The adhesive strength of the sealing material was defined as the tensile load at which separation occurred at the interface between the sheet body 4a and the resin plate 3a, divided by the bonding area of ​​the sheet body 4a to the resin plate 3a. If the adhesive strength is 0.5 MPa or higher, the adhesion can be considered good.

[0054] (5) Sealing test A sealing performance test was performed using the sealing performance test specimen P' prepared as described above. Prior to the sealing performance test, two types of sealing performance test specimen P' were prepared: one that had been subjected to high-temperature storage and another that had been subjected to oil immersion. For high-temperature storage, the sealing performance test specimen P' was left in air at 150°C for 2000 hours. For oil immersion, the sealing performance test specimen P' was immersed in ATF (the same as the one used for measuring the oil resistance mass change rate described above) at 100°C for 500 hours.

[0055] For the sealing performance test, the sealing test piece P', which had undergone the high-temperature exposure or oil immersion described above, was attached to the tip of a tube T as shown in Figure 3C. The tube T used had an internal dimension approximately the same as the external dimension of the housing 3b of the sealing test piece P'. The sealing test piece P' was pressed into the tip of the tube T at the housing 3b, ensuring tight contact between the tube T and the housing 3b. This contained the portion of the sealing test piece P' extending from one end to the middle of the housing 3b within the space inside the tube T. The tip of the tube T with the sealing test piece P' attached was then immersed in water W stored in a water tank. The base end of the tube T was left outside the water W, allowing compressed air A to be introduced from that end.

[0056] Compressed air A at 10 kPa (pressure expressed as differential pressure from atmospheric pressure) was introduced from the base end of tube T for 30 seconds. During this time, the presence or absence of bubbles B was visually observed at the boundary between the model terminal 2b and housing 3b of the sealing test piece P'. The presence or absence of bubbles B indicates that the area between the sealant 4b and housing 3b is not sufficiently sealed, and that compressed air A is leaking from that area. If there was no leakage of bubbles B, the pressure of compressed air A was increased by 10 kPa increments, and the process of determining whether or not bubbles B would form was repeated. The pressure of compressed air A at the point when bubbles B began to form was recorded as the sealing pressure.

[0057] If the sealing pressure was less than 100 kPa, the sealing performance was judged to be poor (B). On the other hand, if the sealing pressure was between 100 kPa and 200 kPa, the sealing performance was judged to be sufficient (A). Furthermore, if the sealing pressure was 200 kPa or higher, the sealing performance was judged to be particularly high (A+).

[0058] [Evaluation Results] Table 1 below shows the evaluation results for each of the sealing materials A1-A3 and B1-B4.

[0059] [Table 1]

[0060] According to Table 1, sealants A1-A3 and B1 and B2 all dissolve in both HFIP and m-cresol. Correspondingly, they achieve adhesive strengths significantly exceeding 0.5 MPa against PA6T. On the other hand, sealants B3 and B4, which neither dissolve nor swell in these solvents, have an adhesive strength of 0 MPa. In other words, they show (almost) no adhesion to PA6T.

[0061] The results of the sealing performance test after high-temperature storage show that sealing materials A1-A3 and B1, B2, which dissolve in both HFIP and m-cresol and exhibit high adhesion to PA6T, all achieved sufficient sealing performance, rated A+ or A. In particular, sealing materials A1-A3 and B1, which have a high adhesive strength of 2 MPa or more, achieved high sealing performance, rated A+. In contrast, sealing materials B3 and B4, which neither dissolve nor swell in HFIP and m-cresol and have low adhesion to PA6T, all showed low sealing performance after high-temperature storage (B). These results indicate that if a sealing material is soluble in both HFIP and m-cresol and exhibits high adhesion to the housing's constituent materials, it can maintain sufficient sealing performance to the housing even when heated to high temperatures. It is also thought that the higher sealing performance of sealing materials A1-A3 and B1 after high-temperature storage compared to sealing material B2 is related to their higher melting points in addition to their higher adhesive strength.

[0062] Next, focusing on the oil resistance mass change rate and sealing performance after oil immersion, sealants A1 to A3, whose oil resistance mass change rate is less than 20% in absolute value, achieved high sealing performance, rated A or A+, after oil immersion. In particular, sealants A1 and A2, whose oil resistance mass change rate is kept below 7%, achieved especially high sealing performance (A+). On the other hand, sealants B1 to B3, whose oil resistance mass change rate is 20% or more, received a low sealing performance rating of B after oil immersion. Although sealant B4 has an oil resistance mass change rate of less than 20% by mass, its adhesive strength is 0 MPa, meaning it is (almost) not adhered to the housing, resulting in a low sealing performance rating of B after oil immersion. For sealant B1, the adhesive strength is high at 2 MPa, and it maintained high sealing performance even after being left at high temperatures in the atmosphere. However, its high oil resistance mass change rate and low oil resistance likely led to a decrease in sealing performance after oil immersion. These results suggest that, in order to maintain sufficient sealing performance even after oil immersion, the sealing material must be able to dissolve or swell in both HFIP and m-cresol, exhibit high adhesion to the housing, and possess high oil resistance such that the oil-resistance mass change rate is kept below 20% by mass.

[0063] The above test results demonstrate that when improving sealing performance in electrical connection components by placing a sealing material between the terminal and the housing, using a material that is soluble or swellable in both HFIP and m-cresol, and has an oil resistance mass change rate of less than 20% by mass, allows for the maintenance of high sealing performance even in environments with high temperatures and contact with lubricating oil.

[0064] Although embodiments of the present disclosure have been described in detail above, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. [Explanation of Symbols]

[0065] 1. Terminal block (electrical connection component) 2 terminals (busbar) 2a copper plate 2b Model Terminal 3 Housing 3a resin board 3b Housing 31 Flange section 32 Holding part 4. Sealant 4a Sheet of sealing material 4b Sealant 5 rubber rings A Compressed air B bubbles P Adhesion test piece P' Sealing test specimen S1 outer space S2 inner space T-tube W water

Claims

1. Terminals and A housing that holds the terminals, A sealing material is disposed between the terminal and the housing, The housing comprises at least one of a polyester resin and a polyamide resin. The aforementioned sealing material is Containing thermoplastic polymers, It is soluble or swollen in both hexafluoroisopropanol and m-cresol. An electrical connection component whose mass change rate is less than 20% when immersed in lubricating oil at 100°C for 8 hours.

2. The electrical connection member according to claim 1, wherein the melting point of the sealing material is 150°C or higher.

3. The electrical connection member according to claim 1 or claim 2, wherein the sealing material includes a thermoplastic elastomer as the thermoplastic polymer.

4. The electrical connection member according to claim 1 or claim 2, wherein the sealing material includes at least one of polyurethane resin, polyester resin, and polyamide resin as the thermoplastic polymer.

5. The electrical connection member according to claim 1 or claim 2, wherein the housing comprises at least one of polybutylene terephthalate, nylon 6T, and nylon 9T.

6. The electrical connection member according to claim 1 or claim 2, wherein the electrical connection member is configured as a terminal block for a motor.

Images