Electrical connection member
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-06
- Publication Date
- 2026-08-13
Smart Images
Figure JP2026004381_13082026_PF_FP_ABST
Abstract
Description
Electrical connection member
[0001] The present disclosure relates to an electrical connection member.
[0002] In an electrical connection member in which a conductive member such as a terminal or an electric wire is held by a resin housing, there may be a problem that water penetrates through the gap between the housing and the conductive member into the interior of the device to which the electrical connection member is attached. Further, in a form in which lubricating oil is used inside the device to which the electrical connection member is attached, it may be required to suppress the leakage of the lubricating oil to the outside of the device through the gap between the housing and the conductive member. In such cases, it is effective to impart sealing properties to the electrical connection member in order to suppress the permeation of water or lubricating oil at the location between the housing and the conductive member. For example, in an automobile driven by a motor, a terminal block is provided on the motor, and power is transmitted from an inverter to the motor through the terminal block. In this type of terminal block, in order to suppress the intrusion of moisture such as rainwater into the motor and to suppress the leakage of the lubricating oil filled in the motor, a sealing material may be provided between the housing and the terminal (bus bar).
[0003] As methods for imparting sealing properties between a housing and a conductive member such as a terminal or an electric wire in an electrical connection member, a plurality of forms are known. First, as disclosed in Patent Document 1 and the like, there is a method of performing surface treatment such as machining or laser processing on the surface of the conductive member to enhance the adhesion between the surface of the conductive member and the housing. Also, as disclosed in Patent Documents 2 to 5 and the like, a method is also used in which a resin material such as a potting agent or an adhesive is disposed at the location between the housing and the conductive member to seal the gap between the housing and the conductive member. Further, as disclosed in Patent Documents 6, 7 and the like, waterproofing may be performed by attaching an elastic member to the conductive member and press-fitting it into the housing.
[0004] Japanese Unexamined Patent Application Publication No. 2016 - 085874, Japanese Unexamined Patent Application Publication No. 2002 - 270283, Japanese Unexamined Patent Application Publication No. 2012 - 204241, Japanese Unexamined Patent Application Publication No. 2024 - 133781, International Publication No. 2017 / 154543, Japanese Unexamined Patent Application Publication No. 2010 - 212081, Japanese Unexamined Patent Application Publication No. 2010 - 218777
[0005] When providing sealing properties to electrical connection members, it is desirable to obtain high sealing performance. Among the various embodiments listed above, the embodiment that provides sealing properties to electrical connection members using an elastic member, as disclosed in Patent Documents 6 and 7, etc., has the potential to easily provide high sealing performance compared to sealing structures that utilize surface treatment or sealing with resin materials, because it involves placing a solid elastic member with a certain volume to prevent the movement of liquid. However, in embodiments that use elastic members in this way, it is necessary to reliably press-fit the elastic member into a predetermined location in the housing and to stably maintain that pressed-in state. For this purpose, a member for performing the operation of press-fitting the elastic member into the housing and a member for maintaining the pressed-in state are required. This may lead to an increase in the number of necessary members, increased structural complexity, and larger size of the electrical connection member.
[0006] In view of the above, the objective is to provide an electrical connection member that can provide high sealing performance with a simple structure using an elastic material.
[0007] The electrical connection member of this disclosure comprises a terminal, a hollow cylindrical elastic sealing member fitted onto the outer circumference of the terminal, and a housing molded onto the outer circumference of the composite in which the elastic sealing member is fitted onto the outer circumference of the terminal, wherein the elastic sealing member is made of a material that is more elastically deformable than the housing, at least a portion of which is embedded inside the housing, and its end face is flush with the outer wall surface of the housing or positioned outside the outer wall surface.
[0008] The electrical connection member described herein is an electrical connection member that uses an elastic member and can provide high sealing performance with a simple configuration.
[0009] Figures 1A and 1B are a side view and a cross-sectional view, respectively, of a terminal block as an electrical connection member according to one embodiment of the present disclosure. Figures 2A and 2B are schematic cross-sectional views illustrating a method for manufacturing a terminal block by molding. Figure 2A shows the case where the elastic sealing member is placed at the end of the housing, and Figure 2B shows the case where the elastic sealing member is placed inside the housing. In each figure, the left-hand drawing shows the state before the resin material solidifies, and the right-hand drawing shows the state after the resin material solidifies. Figure 3A is a side view showing a test piece for a sealing performance test. Figure 3B is a schematic diagram illustrating a method for conducting a sealing performance test.
[0010] [Description of Embodiments of the Disclosure] First, embodiments of the Disclosure will be described. The electrical connection member of the Disclosure has the following configuration.
[0011] [1] The electrical connection member of the present disclosure comprises a terminal, a hollow cylindrical elastic sealing member fitted onto the outer circumference of the terminal, and a housing molded onto the outer circumference of the composite in which the elastic sealing member is fitted onto the outer circumference of the terminal, wherein the elastic sealing member is made of a material that is more elastically deformable than the housing, at least a portion of which is embedded inside the housing, and its end face is flush with the outer wall surface of the housing or positioned outside the outer wall surface.
[0012] In the electrical connection member of this disclosure, the elastic sealing member is fitted onto the outer circumference of the terminal and interposed between the terminal and the housing, thereby preventing the movement of liquid through the gap between the terminal and the housing and providing a sealing effect. Furthermore, in the electrical connection member of this disclosure, the elastic sealing member is not inserted from the outside into a pre-formed housing, but rather the housing is formed by molding around the outer circumference of the elastic sealing member, which forms a composite with the terminal. Therefore, there is no need to use a member for inserting the elastic sealing member into the housing. In addition, because the housing is formed with the elastic sealing member compressed by the resin pressure during molding, the compressed state in which the elastic sealing member is housed within the housing is stably maintained. Therefore, there is no need to provide a member for maintaining the press-fitted state of the elastic sealing member. In this way, high waterproofness can be provided to the electrical connection member with a simple configuration while suppressing the increase in the number of parts, structural complexity, and size that would result from providing an elastic sealing member. It can be confirmed, for example, that the elastic sealing member is compressed by the housing, rather than being inserted after the housing has been formed, by molding the housing onto the outer circumference of the composite of the terminal and the elastic sealing member.
[0013] Furthermore, because the elastic sealing member is positioned such that its end face is flush with the outer wall surface of the housing or located outside the outer wall surface, that is, because the elastic sealing member is positioned at the end of the housing, resin pressure is efficiently applied to the elastic sealing member when the housing is formed by molding, causing the elastic sealing member to be greatly compressed and making it easier to maintain that compressed state. In addition, it becomes less likely for a cavity to form between the elastic sealing member and the housing. As a result, the adhesion between the elastic sealing member and the housing is improved, and the elastic sealing member provides high sealing performance to the electrical connection member.
[0014] [2] In the embodiment of [1] above, the side surface of the terminal may be a curved surface, or the joint portion of the adjacent plane may have a chamfer shape with a chamfer dimension of C0.1 mm or more, or a chamfer shape with a chamfer dimension of R0.1 mm or more. This prevents the force applied to the elastic sealing member from concentrating at the corners of the terminal. This makes it possible to suppress damage such as tearing of the elastic sealing member at the corners of the terminal due to impact when forming the housing by molding, thereby reducing the sealing performance.
[0015] [3] In the embodiment of [1] or [2] above, the elastic sealing member is preferably provided with an elastic modulus of 10 MPa or less at 23°C. This allows the elastic sealing member to exhibit high sealing performance due to its high flexibility, and to maintain that high sealing performance even when subjected to thermal shock. As a result, even when the electrical connection member is used in an environment subject to large temperature changes, such as inside an automobile, it is possible to maintain high sealing performance over a long period of time.
[0016] [4] In any of the embodiments of [1] to [3] above, it is preferable that the dimensions of the area in which the elastic sealing member is embedded in the housing are 1.9 mm or more along the axis of the terminal. This enhances the effect of providing sealing performance by the elastic sealing member, as well as the effect of maintaining that sealing performance when subjected to thermal shock.
[0017] [5] In any of the embodiments described in [1] to [4] above, the elastic sealing member is preferably subject to a mass change rate of 10% or less when immersed in lubricating oil at 100°C for 8 hours. In this case, the elastic sealing member is less likely to dissolve or swell even when in contact with high-temperature lubricating oil, and exhibits high sealing performance with respect to the lubricating oil.
[0018] [6] In any of the embodiments described in [1] to [5] above, the housing may have a gate mark from the molding process on an outer wall surface different from the surface on which the elastic sealing member is located. The position of the gate mark corresponds to the position where molten resin is introduced when the housing is formed by molding. By introducing molten resin from a surface different from the surface on which the elastic sealing member is located, a large resin pressure is more easily applied to the elastic sealing member. As a result, the elastic sealing member is effectively compressed by the resin pressure and more easily adheres to the formed housing. This provides a high degree of improvement in sealing performance.
[0019] [7] In any of the embodiments described in [1] to [6] above, the elastic sealing member is preferably compressed by the housing throughout the entire region embedded in the housing. This increases the adhesion between the elastic sealing member and the housing, making it easier to obtain a high level of sealing performance. When the elastic sealing member is press-fitted into a pre-molded housing, even if a retaining member or the like is provided to fix the elastic sealing member, the portion of the elastic sealing member that is compressed tends to be limited to the vicinity of the housing wall or the portion that comes into contact with the retaining member. However, by forming the housing around the outer circumference of the elastic sealing member by molding, the elastic sealing member is more easily compressed throughout the entire region embedded in the housing by the resin pressure.
[0020] [8] In any of the embodiments described in [1] to [7] above, the elastic sealing member may include at least one of acrylic rubber, fluororubber, and polyester thermoplastic elastomer. In this case, the elastic sealing member will have excellent elasticity and will be compressed by the resin pressure to exhibit high sealing performance. Furthermore, acrylic rubber, fluororubber, and polyester thermoplastic elastomer also have excellent oil resistance.
[0021] [9] In any of the embodiments described in [1] to [8] above, the housing may contain at least one of polybutylene terephthalate, nylon 66, nylon 6T, nylon 9T, polyphenylene sulfide, and syndiotactic polystyrene. Housings containing these resins have excellent heat resistance, strength, and insulation properties.
[0022]
[10] In any of the embodiments described in [1] to [9] above, the electrical connection member may be configured as a terminal block for a motor. A terminal block for a motor is desirable to have high sealing performance that can suppress the ingress of water from outside the motor and the leakage of lubricating oil from inside the motor. The electrical connection member of this disclosure has high sealing performance and can be suitably used as a terminal block for a motor.
[0023] [Details of Embodiments of the Disclosure] An electrical connection member according to one embodiment of the Disclosure will be described in detail below with reference to the drawings. Unless otherwise specified, the various characteristics described below are values measured at room temperature (approximately 23°C) in the atmosphere.
[0024] <Configuration of Electrical Connection Member> The electrical connection member of this disclosure has a terminal and a housing that passes through and holds the terminal, and further has an elastic sealing member disposed between the terminal and the housing. The electrical connection member is not particularly limited in type as long as it has a terminal and a housing and an elastic sealing member can be disposed between the terminal and the housing, and examples include terminal blocks, connectors, etc. A terminal block will be described below as a preferred example of an electrical connection member.
[0025] 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 the section A-A in Figure 1A. The terminal block 1 has one or more (in this case, three) terminals (busbars) 2 and a housing 3. An elastic sealing member 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.
[0026] 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 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. Surface treatment such as forming fine grooves on the surface of the terminal 2 may be applied to improve the adhesion to the components of the housing 3, but even without surface treatment, a sufficiently high sealing performance can be obtained in the terminal block 1 due to the contribution of the elastic sealing member 4.
[0027] The shape of terminal 2 is not particularly limited, but if it has a corner on its side, that is, a part on its side where two planes are joined at an angle, as will be explained later, damage to the elastic sealing member 4 may occur in the part of the elastic sealing member 4 that comes into contact with the corner during the molding of the housing 3. For this reason, it is preferable that terminal 2 does not have a corner on its side. In other words, it is preferable that terminal 2 has a shape in which the side surface is composed of a curved surface, such as a cylindrical shape. Also, if terminal 2 has a shape in which it has a plane on its side, such as a flat plate or a rectangular prism plate, it is preferable that a chamfered shape is formed at the joint of adjacent planes. Examples of chamfered shapes include C-chamfered shapes and R-chamfered shapes. From the viewpoint of effectively suppressing the influence of corners, the chamfered dimension in the C-chamfered shape is preferably C0.1 mm or more, and more preferably C0.2 mm or more. The chamfered dimension (chamfer radius) in the R-chamfered shape is also preferably R0.1 mm or more, and more preferably R0.2 mm or more. There is no particular upper limit set for the chamfer dimensions; it is sufficient to keep the outer shape of terminal 2 within a range that does not deviate significantly from a flat plate or prism shape.
[0028] The housing 3 holds the terminals 2 by passing through them. In other words, the housing 3 surrounds the outer circumference of the terminals 2 in at least a portion of the area of the terminals 2 and holds the terminals 2. In the illustrated configuration, the housing 3 integrally has a block-shaped holding portion 32 and a flat flange portion 31. The holding portion 32 is the part that holds the terminals 2, and each terminal 2 is embedded in the holding portion 32 of the housing 3 in the middle of the axial direction. The holding portion 32 holds the three terminals 2 together, arranged in parallel with spaces between them. The flange portion 31 is formed in an annular shape surrounding the holding portion 32 and functions as a mounting portion when attaching the terminal block 1 to a device or the like. At least the area surrounding the elastic sealing member 4 of the housing 3 is constructed as a solid body. In the illustrated configuration, the entire area of the housing 3 is constructed as a solid body, except for the unavoidable gaps that occur around the outer circumference of the terminals 2.
[0029] The constituent materials of the housing 3 are not particularly limited and can be made from various insulating materials. Suitable constituent materials include polyester resins such as polybutylene terephthalate (PBT), polyamide resins such as nylon 66 (PA66), nylon 6T (PA6T), and nylon 9T (PA9T), and engineering plastics such as polyphenylene sulfide (PPS) and syndiotactic polystyrene (SPS), as well as other resin materials. In particular, from the viewpoint of excellent heat resistance, strength, and insulation, it is preferable that the housing 3 contains at least one of PBT, PA66, PA6T, PA9T, PPS, and SPS. In addition to resin materials, the constituent materials of the housing 3 may also contain additives such as anti-aging agents as appropriate.
[0030] The elastic sealing member 4 is made of a material that is more elastically deformable than the housing 3. In other words, it is made of a material with a lower modulus of elasticity than the housing 3. The elastic sealing member 4 has a hollow cylindrical (ring-shaped) structure and is fitted onto the outer circumference of the terminal 2. That is, the terminal 2 is inserted through the hollow portion of the elastic sealing member 4. The inner circumference of the hollow portion of the elastic sealing member 4 is smaller than the outer circumference of the terminal 2, so that the terminal 2 is press-fitted into the elastic sealing member 4. The length of the elastic sealing member 4 is shorter than the length of the region in which the terminal 2 penetrates the housing 3, along the axis of the terminal 2.
[0031] The elastic sealing member 4 is positioned between the housing 3 and the terminal 2, thereby sealing the space between the terminal 2 and the housing 3. In other words, the elastic sealing member 4 seals the space between the terminal 2 and the housing 3 so as to block 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). By sealing the space between the terminal 2 and the housing 3, the elastic sealing member 4 plays a role in preventing liquids, such as 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. The type and physical properties of the constituent material of the elastic sealing member 4 are not particularly specified, but preferred forms will be described later.
[0032] The elastic sealing member 4, fitted onto the outer circumference of the terminal 2, has at least a portion of its area embedded inside the housing 3. Here, the end face 41 of the elastic sealing member 4 is flush with the outer wall surface of the housing 3. Alternatively, the end face 41 of the elastic sealing member 4 is positioned outside the outer wall surface 33 of the housing 3. In either case, the end face 41 of the elastic sealing member 4 is exposed to the space outside the housing 3 (in this case, the outer space S1). In the illustrated configuration, the upper end face 41 of the elastic sealing member 4 is flush with the upper wall surface 33 of the housing 3. In other words, the positions of the surfaces exposed to the space outside the housing 3 are aligned with each other on the housing 3 and the elastic sealing member 4 (including cases where there are minute misalignments between surfaces, such as those unavoidable due to manufacturing tolerances).
[0033] The elastic sealing member 4 can achieve sufficiently high sealing performance if it is provided only at one end of the housing 3 along the axis of the terminal 2. In the illustrated configuration, the elastic sealing member 4 is provided only at the upper end of the housing 3. However, the elastic sealing member 4 may also be provided at the other end of the housing 3 (the lower end in the illustrated configuration) along the axis of the terminal 2. In that case, the end face (lower end face) of the second elastic sealing member 4 should be flush with the outer wall surface (lower wall surface) of the housing 3, or positioned outside the outer wall surface.
[0034] The terminal block 1 according to this embodiment is not formed by inserting an elastic sealing member 4, or a composite of the elastic sealing member 4 and the terminal 2, from the outside into a housing 3 that has been pre-formed into a predetermined shape. Instead, the housing 3 is formed by molding the outer circumference of a composite in which the elastic sealing member 4 is fitted around the outer circumference of the terminal 2. The method of forming the housing 3 and the resulting characteristics will be described in detail later.
[0035] 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 or the like, 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 or the like and the flange portion 31.
[0036] The 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 the terminal block 1 can be attached. The portion of the terminal block 1 corresponding to the inner space S2 can be inserted into the opening, and the terminal block 1 can be fixed to the device with the flange portion 31. The portion of the terminal block 1 corresponding to the outer space S1 will protrude to the outside of the device. Because the 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 the terminal block 1 is unlikely to occur. In other words, the movement of liquids through the gap between the terminal 2 and the housing 3 is suppressed by the elastic sealing member 4, and the movement of liquids through the gap between the 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. At the same time, the leakage of liquids such as lubricating oil placed inside the device to the outside of the device is also effectively suppressed.
[0037] The type of device to which the terminal block 1 is attached is not particularly limited. However, as will be explained later, the terminal block 1 according to this embodiment exhibits high sealing performance through the elastic sealing member 4, and can therefore be suitably applied to devices that require high sealing performance. Examples of such devices include motors, particularly motors for automobiles. In automobile motors, it is necessary to suppress the intrusion of moisture from the outdoor environment, such as rainwater, so the terminal block 1 is required to have high waterproofness. Furthermore, the terminal block 1 according to this embodiment can maintain high sealing performance even when subjected to thermal shock if the constituent materials and dimensions of the elastic sealing member 4 are appropriately set. In the case of a motor terminal block 1, a large amount of heat tends to be generated when energized, and a large temperature change occurs with the operation / stopping of the motor, so it is also advantageous that it can maintain high sealing performance even after undergoing thermal shock due to such temperature changes.
[0038] <Relationship between elastic sealing member and housing> As described above, in the terminal block 1 according to this embodiment, a housing 3 is formed on the outer circumference of the composite of the elastic sealing member 4 and the terminal 2 by molding. Figure 2A shows a schematic cross-sectional view of the state when the housing 3 is formed by molding. First, as shown in the left figure, a mold 9 having a cavity corresponding to the desired shape of the housing 3 is prepared, and the composite, in which a hollow cylindrical elastic sealing member 4 is fitted around the outer circumference of the terminal 2, is placed at a predetermined position inside the mold 9. At this time, the position of the elastic sealing member 4 along the axis of the terminal 2 and the position of the composite in the housing 3 are set so that the end face 41 of the elastic sealing member 4 is flush with the outer wall surface 33 of the housing 3, or is positioned outside the outer wall surface 33 of the housing 3. In the illustrated form, the end face 41 of the elastic sealing member 4 and the upper wall surface 33 of the housing 3 are set to be flush.
[0039] When the composite of the elastic sealing member 4 and the terminal 2 is installed in the mold 9, molten resin material 3', which will be the constituent material of the housing 3, is introduced through the gate portion 91 provided as an opening in the mold 9 (arrow A1). In the illustrated configuration, the elastic sealing member 4 is positioned to correspond to the upper wall surface 33 of the housing 3, while the gate portion 91 is positioned to correspond to a different surface of the housing 3 (the lower wall surface in the figure) from the upper wall surface 33. As the molten resin 3' is introduced, resin pressure from the molten resin 3' is applied to the elastic sealing member 4. The resin pressure acts on the elastic sealing member 4 from the outside to the inside, compressing the elastic sealing member 4 (arrow A2). In particular, because the elastic sealing member 4 is positioned at the end of the cavity inside the mold 9, a large resin pressure acts as a compressive force that presses the elastic sealing member 4 against the wall surface of the mold 9, so the elastic sealing member 4 is compressed efficiently.
[0040] After introducing the molten resin 3', the mold 9 is cooled, and the solidification of the molten resin 3' progresses. Solidification proceeds first from the outer portion of the molten resin 3' that is in contact with the wall surface of the mold 9, and the solidification of the inner portion that is away from the wall surface of the mold 9 is slower. The right diagram in Figure 2A shows the state after solidification. In the inner part of the housing 3, the solidification of the molten resin 3' is slow, so due to the effect of solidification shrinkage (arrow A3), there is a possibility that a cavity V will be created where the resin is not filled (resin sink mark). However, since the elastic seal member 4 is positioned at the end of the mold 9, the solidification of the molten resin 3' occurs quickly around the elastic seal member 4. Therefore, the molten resin 3' adheres closely to the outer circumference of the elastic seal member 4, which remains compressed by the resin pressure, and solidifies, holding the elastic seal member 4 in a compressed state. A cavity V due to resin sink mark is also less likely to form around the elastic seal member 4. In this way, by arranging the elastic sealing member 4 at the end of the mold 9 and forming a structure in which the elastic sealing member 4 is located at the end of the housing 3, a terminal block 1 is obtained in which the compressed elastic sealing member 4 is held in close contact with the housing 3. Due to the effects of compression and close contact of the elastic sealing member 4, high sealing performance is provided between the terminal 2 and the housing 3.
[0041] Here, Figure 2B shows the process of forming the housing 3 when the elastic sealing member 4 is positioned in the middle of the housing 3 along the axis of the terminal 2, rather than at the end of the housing 3. In this case, during the process of forming the housing 3, the molten resin 3' is introduced into the mold 9 with the elastic sealing member 4 positioned inward, away from the wall surface of the mold 9. As a result, compared to the case where the elastic sealing member 4 is positioned at the end of the mold 9, the force that compresses the elastic sealing member 4 due to the resin pressure of the molten resin 3' is less likely to act. Also, because the elastic sealing member 4 is located in the interior of the mold 9 where the solidification of the molten resin 3' is slower, a cavity V is more likely to form around the elastic sealing member 4 due to resin shrinkage. This cavity V acts as a passage for liquids such as water in the terminal block 1, which can reduce the sealing performance. Furthermore, even if the elastic sealing member 4 is compressed by the resin pressure, the formation of the cavity V around it may prevent the compressed state from being maintained, which can also contribute to a decrease in sealing performance.
[0042] In this way, by forming the housing 3 by mold molding with the elastic sealing member 4 positioned at the end of the mold 9, a terminal block 1 with higher sealing performance can be obtained compared to the case where the elastic sealing member 4 is positioned inside the mold 9. In a terminal block 1 with the elastic sealing member 4 positioned at the end of the housing 3, it can be confirmed, for example, by the compressed state of the elastic sealing member 4, the degree of contact with the housing 3, and the position of the gate marks resulting from the mold molding, that the elastic sealing member 4 was not inserted from the outside into the previously molded housing 3, but rather that the housing 3 was formed by mold molding on the outer circumference of the composite of the elastic sealing member 4 and the terminal 2.
[0043] If the elastic sealing member 4 is inserted into the housing 3 from the outside, compression of the elastic sealing member 4 is unlikely to occur, and even if it does, it tends to be limited to the area in contact with the surrounding members, such as the walls of the housing 3 or the retaining member, and its vicinity. In contrast, as described above, when the elastic sealing member 4 is housed in the end of the mold 9 and molded, the elastic sealing member 4 is compressed by the resin pressure, and the molten resin 3' surrounding the elastic sealing member 4 solidifies quickly in that state, ultimately maintaining the compressed state of the elastic sealing member 4. Furthermore, this compression occurs over a wide area of the elastic sealing member 4, including the entire area embedded in the housing 3. Also, if the elastic sealing member 4 is inserted into the housing 3 from the outside, the elastic sealing member 4 can be detached from the housing 3 relatively easily by pulling or other operations. In contrast, when the housing 3 is molded around the outer circumference of the elastic sealing member 4, the adhesion between the elastic sealing member 4 and the housing 3 is high, so the elastic sealing member 4 will not detach from the housing 3 even with the force applied by pulling with your fingers.
[0044] Further, when forming the housing 3 by injection molding, as a trace of the gate portion 91 for introducing the molten resin 3' into the mold 9, a protruding gate mark is formed at the position on the surface of the housing where the gate portion 91 was located. The compression of the elastic seal member 4 by the resin pressure occurs effectively by introducing the molten resin 3' from the gate portion 91 away from the position where the elastic seal member 4 is disposed in the mold 9. Therefore, in the mold 9 during injection molding, it is effective to provide the gate portion 91 on a surface of the mold 9 different from the surface on which the elastic seal member 4 is disposed, particularly on a surface intersecting or opposing the surface on which the elastic seal member 4 is provided, for manufacturing the terminal block 1 having high sealing performance. Among them, it is preferably provided on the opposing surface. In those cases, in the manufactured terminal block 1, the gate mark is formed on a surface different from the surface 33 (the upper wall surface in FIGS. 1A and 1B) on which the elastic seal member 4 is disposed on the outer wall surface of the housing that intersects or opposes the surface on which the elastic seal member 4 is disposed (the side wall surface or the lower wall surface in FIGS. 1A and 1B).
[0045] By forming the housing 3 by injection molding on the outer periphery of the elastic seal member 4 and the terminal 2, unlike the case of inserting the elastic seal member 4 from the outside into the previously formed housing 3, there is no need to provide members such as a member for inserting the elastic seal member 4 and a pressing member for holding the state in which the elastic seal member is inserted into the housing, and the number of parts can be reduced. The complication and enlargement of the structure of the terminal block 1 can also be suppressed. Thus, the terminal block according to the present embodiment has a simple configuration and can impart high sealing performance.
[0046] In the terminal block 1, the elastic sealing member 4 can achieve high sealing performance by utilizing the molding process of the housing 3, as described above, as long as its end face 41 is positioned flush with the outer wall surface 33 of the housing 3 or outside the outer wall surface 33. Therefore, the specific position and dimensions of the elastic sealing member 4 within the housing 3 are not specified. However, it is preferable that the end face 41 of the elastic sealing member 4 is flush with the outer wall surface 33 of the housing 3, as this allows for a smaller overall size of the terminal block 1 and reduces the likelihood of interference with external components or damage to the elastic sealing member 4 due to external forces. Even when the end face 41 of the elastic sealing member 4 is positioned outside the outer wall surface 33 of the housing 3, it is preferable to keep the protrusion height of the elastic sealing member 4 beyond the outer wall surface 33 of the housing 3 to 0.5 mm or less.
[0047] Furthermore, a larger embedding depth L of the elastic sealing member 4, that is, a larger area where the elastic sealing member 4 is embedded in the housing 3 along the axis of the terminal 2, results in higher sealing performance by the elastic sealing member 4. It also makes it easier to maintain high sealing performance when the terminal block 1 is subjected to thermal shock. In particular, an embedding depth L of 1.9 mm or more, and more preferably 2.2 mm or more, is preferable. While there is no specific upper limit on the embedding depth L, it is advisable to keep it around 3.0 mm or less to avoid using an excessively thick elastic sealing member 4. When the end face 41 of the elastic sealing member 4 is flush with the outer wall surface 33 of the housing 3, the embedding depth L corresponds to the thickness of the elastic sealing member 4 itself. When the terminal block 1 includes multiple terminals 2, the elastic sealing member 4 may be provided as a large unit having multiple hollow sections through which the terminals 2 are inserted, sealing all of the terminals 2 at once. However, it is preferable to provide multiple elastic sealing members 4, each having only one hollow section through which the terminals 2 are inserted, sealing each terminal 2 individually, independently and spaced apart from one another. This is because having multiple elastic sealing members 4 independently makes it easier for the resin pressure during the molding of the housing 3 to be applied to each position of the elastic sealing member 4.
[0048] As described above, it is preferable that the terminal 2 has a structure in which the side surface is formed of a curved surface or has a chamfered shape at the joint of adjacent surfaces and does not have a corner. If the terminal 2 has a corner, at the corner portion, the force tends to concentrate on the elastic seal member 4 that contacts the outer periphery of the terminal 2. When the resin pressure is applied to the elastic seal member 4 along with the mold molding of the housing 3, the impact due to the resin pressure also tends to concentrate on the corner portion, and there is a possibility that damage such as a tear occurs in the elastic seal member 4 due to the impact. The damage to the elastic seal member 4 also leads to a decrease in the sealing performance. If the terminal 2 does not have a corner, the decrease in the sealing performance due to the damage can be effectively suppressed.
[0049] <Constituent Material of Elastic Seal Member> The constituent material of the elastic seal member 4 is not particularly limited as long as it is an insulating material that is more easily elastically deformed than the housing 3. Various polymers such as rubber and elastomer can be preferably used. In particular, a material containing at least one of acrylic rubber, fluorine rubber, and polyester-based thermoplastic elastomer can be preferably used. Acrylic rubber, fluorine rubber, and polyester-based thermoplastic elastomer have excellent elasticity and sealing performance. They are also excellent in oil resistance and heat resistance. In addition to the polymer, the elastic seal member 4 may contain various additives. Examples of the additives include coloring pigments, anti-aging agents, inorganic fillers, storage stabilizers, dispersants, and the like.
[0050] The elastic sealing member 4 preferably has an elastic modulus of 70 MPa or less at 23°C. More preferably, the elastic modulus is 10 MPa or less. In these cases, the elastic sealing member 4 has high flexibility and is easily compressed during the molding of the housing 3, and it adheres closely to the housing 3 and terminal 2, thereby exhibiting high sealing performance. Furthermore, if the elastic modulus is 10 MPa or less, it can be flexibly deformed even when subjected to thermal shock, thereby effectively maintaining its high sealing performance. From the viewpoint of enhancing these effects, it is more preferable that the elastic modulus is 8 MPa or less, and even more preferably 7 MPa or less. When the elastic sealing member 4 is made of a material containing rubber, a low elastic modulus of 10 MPa or less is easily obtained. There is no particular lower limit set for the elastic modulus of the elastic sealing member 4, but from the viewpoint of ensuring material strength, it is preferable to set it to, for example, 1 MPa or more. In this specification, elastic modulus refers to compressive elastic modulus.
[0051] Furthermore, it is preferable that the elastic sealing member 4 has high oil resistance. This ensures that even when the terminal block 1 is placed in a device that uses lubricating oil, such as a motor, it exhibits high sealing performance against the permeation of lubricating oil. Specifically, it is preferable that the mass change rate (hereinafter referred to as the oil-resistant mass change rate) of the elastic sealing member 4 when immersed in lubricating oil at 100°C for 8 hours is 10% or less. Here, the oil-resistant mass change rate of the elastic sealing member 4 is expressed as an absolute value of the ratio of the change in mass due to immersion, i.e., the decrease or increase, based on the mass before immersion in lubricating oil. A small oil-resistant mass change rate indicates that even when the elastic sealing member 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, it indicates that the elastic sealing member 4 has high oil resistance and is less likely to undergo deterioration or change in properties due to the influence of lubricating oil, or to experience the permeation of lubricating oil, even when in contact with high-temperature lubricating oil. More preferably, the oil-resistant mass change rate is 7% or less, and even more preferably 5% or less. There is no specific lower limit set for the oil resistance mass change rate, but it is generally 0.5% or higher. There are no particular restrictions on the specific type of lubricant used to evaluate the oil resistance mass change rate, but it is preferable to use a lubricant that may come into contact with the elastic seal member 4, such as the lubricant used in the device for attaching the terminal block 1. For example, it is preferable to use ATF (Automatic Transmission Fluid) as the lubricant. ATF is sometimes used to fill motors in automobiles.
[0052] Examples are shown below. Here, the relationship between the arrangement and configuration of elastic sealing members in electrical connection members and their sealing performance was investigated. In these examples, unless otherwise specified, the characteristics were evaluated at room temperature (23°C) in air.
[0053] [Sample Preparation] The following materials were prepared as components for the housing: ・PBT: "Duranex CG7030" manufactured by Polyplastics ・PA66: "Zytel HTN70G35HSLR BK267" manufactured by Celanese ・PA6T: "Zytel HTN54G35EF BK420" manufactured by Celanese ・PA9T: "Genestar G1300H" manufactured by Kuraray ・PPS: "Z240" manufactured by DIC ・SPS: "S143" manufactured by Idemitsu Kosan
[0054] The following materials were prepared as elastic sealing members. Rubbers A, B, E and Elastomer A were molded into ring-shaped elastic sealing members. Rubbers C and D were used as ring-shaped products. All of these materials are more elastically deformable than the constituent materials of the housing. • Rubber A: Acrylic rubber - "Nipol AR71" manufactured by Nippon Zeon Co., Ltd. • Rubber B: Fluororubber - "AFLAS 400E" manufactured by AGC Inc. • Rubber C: Silicone rubber - "O-ring P (for motion) Type 4C" manufactured by Masuoka Co., Ltd. • Rubber D: Polytetrafluoroethylene - "PTFE O-ring" purchased from Sansho Co., Ltd. • Rubber E: Ethylene propylene rubber - "NORDEL 6565XFC EPDM" manufactured by DOW Corporation • Elastomer A: Polyester thermoplastic elastomer (TPEE) - Synthetic product
[0055] As model terminals, we prepared some made of aluminum with the following shapes. For the rectangular bars, we used rectangular bars with a cross-section of 3 mm x 12 mm perpendicular to the axis. ・Round core: φ11 mm cylinder ・Rectangular bar C0.3: Rectangular bar with a C0.3 mm chamfer ・Rectangular bar C0.2: Rectangular bar with a C0.2 mm chamfer ・Rectangular bar C0.1: Rectangular bar with a C0.1 mm chamfer ・Rectangular bar R0.2: Rectangular bar with a R0.2 mm chamfer ・Rectangular bar R0.1: Rectangular bar with a R0.1 mm chamfer In addition, we also prepared some made of copper with the shape of the rectangular bar C0.3 above. All model terminals were made without any surface treatment such as the formation of fine grooves, and had smooth surfaces.
[0056] For samples A1 to A19 and samples B1 and B2, the constituent materials for the housing and elastic sealing member, as well as the model terminals, were selected in the combinations shown in Tables 1 and 2. Then, using the selected materials, test pieces simulating terminal blocks were prepared to evaluate the sealing performance. As shown in the side view in Figure 3A, test piece P has a structure in which a block-shaped housing 3a is formed by molding around the outer circumference of a model terminal 2a into which an elastic sealing member 4a is fitted. The housing 3a was formed by molding around the outer circumference of the composite of the elastic sealing member 4a and the model terminal 2a. During molding, molten resin was introduced into the mold from a gate portion located at a position corresponding to the side wall surface of the housing 3a.
[0057] In this process, the position of the elastic sealing member 4a in the formed housing 3a was selected by selecting the position in which the elastic sealing member 4a is fitted into the model terminal 2a, and the position in which the composite of the elastic sealing member 4a and the model terminal 2a is placed within the mold. In samples A1 to A9 and A11 to A19, the end face of the elastic sealing member 4a was made flush with the wall surface (upper wall surface) of the housing 3a (indicated as "flush" in Tables 1 and 2). In sample A10, the end face of the elastic sealing member 4a protruded 0.5 mm outward from the upper wall surface of the housing 3a (indicated as "protruding"). In samples B1 and B2, the elastic sealing member 4a was positioned at the 3 / 4 position from the bottom and the center position, respectively, relative to the vertical dimension (60 mm) of the housing 3a (indicated as "3 / 4 position" and "center," respectively). In both samples B1 and B2, the elastic sealing member 4a was completely surrounded by the housing 3a.
[0058] In addition, a test specimen of sample C1 was prepared as a reference sample. In sample C1, a housing with a space for inserting an elastic sealing member was pre-formed on the outer circumference of the model terminal. Then, the elastic sealing member was inserted into the housing from the outside (referred to as "post-insertion"). The insertion position of the elastic sealing member was such that its end face was flush with the upper wall surface of the housing.
[0059] [Evaluation of Properties] The physical properties of each elastic sealing member and the properties of the electrical connection member were evaluated through the following tests.
[0060] <Physical properties of the elastic sealing member> (1) The compressive modulus of the elastic sealing member was measured at 23°C using an elastic modulus nanoindenter.
[0061] (2) Oil Resistance Mass Change Rate Two g of each elastic seal member was taken, its mass was measured, and it was placed in a container. The entire container was then immersed in lubricating oil (Shell Lubricants Japan ATF "CVTF S-NS-3"). In this state, it was left at 100°C for 8 hours. After that, the elastic seal members were removed from the lubricating oil, the surface lubricating oil was wiped off, and the mass of the elastic seal members was measured. The rate of change in mass was then calculated based on the mass of the elastic seal member before immersion, and this was defined as the oil resistance mass change rate.
[0062] <Characteristics of Electrical Connection Components> (1) Sealing Test A sealing test was performed using the test piece P prepared as described above. Prior to the sealing test, a test piece P in its initial state as prepared was prepared. In addition, for each sample except for samples A18 and A19, samples that had undergone thermal shock were also prepared. For thermal shock, the test piece P was placed in a thermal test chamber and a thermal cycle of heating and cooling between -35°C and 145°C was repeated 1000 times. One thermal cycle consisted of the following steps in order: holding at 145°C for 15 minutes, cooling from 145°C to -35°C for 10 minutes, holding at -35°C for 15 minutes, and heating from -35°C to 145°C for 10 minutes.
[0063] For the sealing performance test, the test specimen P, either in its initial state or after thermal shock, was attached to the tip of the tube T as shown in Figure 3B. The tube T used had an inner dimension approximately the same as the outer dimension of the housing 3a of the test specimen P. The test specimen P was pressed into the tip of the tube T at the location of the housing 3a, ensuring that the tube T was tightly fitted to the housing 3a. This allowed the portion of the test specimen P, from its upper end to the middle of the housing 3a, to be housed within the space inside the tube T. The tip of the tube T with the attached test specimen P 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 G to be introduced from that end.
[0064] Compressed air G 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 2a and the housing 3a of the test piece P. The presence or absence of bubbles B indicates that the area between the model terminal 2a and the housing 3a is not sufficiently sealed, and that compressed air G is leaking from that area. If no bubbles B leaked from any of the three model terminals 2a, the pressure of the compressed air G was increased by 10 kPa increments, and the process of determining whether or not bubbles B would form was repeated. The pressure of the compressed air G when bubbles B began to form from at least one model terminal 2a was recorded as the sealing pressure.
[0065] If the sealing pressure was 200 kPa or higher, it was judged to have high sealing performance (A). On the other hand, if the sealing pressure was less than 200 kPa, it was judged to have low sealing performance (B).
[0066] (2) Oil resistance The oil resistance mass change rate measured for each elastic sealing member above was evaluated as high oil resistance (A) if it was 10% or less. On the other hand, if the oil resistance mass change rate exceeded 10%, it was evaluated as low oil resistance (B).
[0067] (3) Overall Evaluation Based on the results of the sealing performance tests and the oil resistance assessments described above, the characteristics of each sample were comprehensively evaluated. Samples that were judged to have high sealing performance (A) in both the initial state and after thermal shock, and also judged to have high oil resistance, were evaluated as particularly excellent (A+). Samples that were judged to have low sealing performance (B) in at least one of the sealing performance after thermal shock and oil resistance, but also judged to have high sealing performance in the initial state, were evaluated as excellent (A). Samples that were judged to have high sealing performance (A) in the initial state and also judged to have high oil resistance, even though the sealing performance test after thermal shock was omitted, were also evaluated as excellent (A). On the other hand, samples that were judged to have low sealing performance (B) in the initial state were evaluated as inferior (B).
[0068] [Evaluation Results] Table 1 below shows the composition of samples A1 to A10, and Table 2 shows the composition of samples A11 to A19, B1, B2, and C1, along with the results of each evaluation.
[0069]
[0070]
[0071] According to Tables 1 and 2, in samples A1 to A19, where the end face of the elastic sealing member is flush with the outer wall surface of the housing or positioned outside the outer wall surface, high sealing performance was obtained in the initial state (A in the initial sealing performance test, and A+ or A in the overall evaluation). On the other hand, in samples B1 and B2, where the entire area of the elastic sealing member is embedded in the housing and the end face of the elastic sealing member is located inside the outer wall surface of the housing, sufficient sealing performance was not obtained in the initial state (B in the initial sealing performance test and overall evaluation). From the comparison of samples A1 to A19 and samples B1 and B2, it can be confirmed that the electrical connection member can achieve high sealing performance when it has a structure in which the housing is formed on the outer circumference of the composite of the elastic sealing member and the model terminal, and when the end face of the elastic sealing member is flush with the outer wall surface of the housing or positioned outside the outer wall surface. When the test pieces of samples A1 to A19 were observed visually from above in Figure 3A, it was confirmed that the elastic sealing member was compressed by the housing around the entire circumference of the model terminal.
[0072] Furthermore, among samples A1 to A17, samples A1 to A10 and A14 to A17, in which the embedding depth of the elastic sealing member (thickness of the elastic sealing member) is 1.9 mm or more and the elastic modulus is 10 MPa or less, exhibit high sealing performance not only in the initial state but also after undergoing thermal shock. These samples also show high oil resistance of the elastic sealing member, and are evaluated as excellent overall (A+). In other words, they maintain high sealing performance even after undergoing thermal shock and exhibit high sealing performance not only against water but also against lubricating oil.
[0073] In samples A1 to A17, a rubber material was used as the elastic sealing material, while in samples A18 and A19, an elastomer material was used as the elastic sealing member. However, samples A18 and A19 also achieved the same sealing performance and oil resistance as samples A1 to A17. In other words, elastomer materials can be suitably used as elastic sealing members, just like rubber materials. The material of the model terminal was aluminum in sample A18 and copper in sample A19, but the evaluation results were the same for both, indicating that the terminal material does not substantially affect the sealing performance of the electrical connection member.
[0074] Sample C1, prepared as a reference sample, is a housing that was formed in advance, into which an elastic sealing member was inserted later. Sample C1 also showed high sealing performance. However, when inserting the elastic sealing member later in this manner, it becomes necessary to provide components such as retaining members to fix the inserted elastic sealing member inside the housing, which increases the number of parts. This is disadvantageous compared to the form in which the housing is molded around the outer circumference of the elastic sealing member, as in samples A1 to A19.
[0075] 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.
[0076] 1 Terminal block (electrical connection component) 2 Terminal (bus bar) 2a Model terminal 3 Housing 3' Molten resin 3a Housing 31 Flange portion 32 Holding portion 33 Outer wall surface of housing (upper wall surface) 4 Elastic sealing member 4a Elastic sealing member 41 End face of elastic sealing member 5 Rubber ring 9 Mold 91 Gate portion A1 Introduction of molten resin A2 Compression of elastic sealing member by resin pressure A3 Curing shrinkage of resin material B Air bubbles G Compressed air L Embedding depth P Test piece S1 Outer space S2 Inner space T Tube V Cavity W Water
Claims
1. An electrical connection member comprising: a terminal; a hollow cylindrical elastic sealing member fitted onto the outer circumference of the terminal; and a housing molded onto the outer circumference of the composite in which the elastic sealing member is fitted onto the outer circumference of the terminal, wherein the elastic sealing member is made of a material that is more elastically deformable than the housing, at least a portion of which is embedded inside the housing, and the end face is flush with the outer wall surface of the housing or positioned outside the outer wall surface.
2. The electrical connection member according to claim 1, wherein the side surface of the terminal is composed of a curved surface, or the joint portion of the adjacent plane has a chamfer shape with a chamfer dimension of C0.1 mm or more, or a chamfer shape with a chamfer dimension of R0.1 mm or more.
3. The electrical connection member according to claim 1 or claim 2, wherein the elastic sealing member has an elastic modulus of 10 MPa or less at 23°C.
4. The electrical connection member according to any one of claims 1 to 3, wherein the dimensions of the area in which the elastic sealing member is embedded in the housing are 1.9 mm or more along the axis of the terminal.
5. The electrical connection member according to any one of claims 1 to 4, wherein the elastic sealing member has a mass change rate of 10% or less when immersed in lubricating oil at 100°C for 8 hours.
6. The electrical connection member according to any one of claims 1 to 5, wherein the housing has a gate mark resulting from molding on an outer wall surface different from the surface on which the elastic sealing member is located.
7. The electrical connection member according to any one of claims 1 to 6, wherein the elastic sealing member is compressed by the housing throughout the entire region in which it is embedded in the housing.
8. The electrical connection member according to any one of claims 1 to 7, wherein the elastic sealing member comprises at least one of acrylic rubber, fluororubber, and polyester thermoplastic elastomer.
9. The electrical connection member according to any one of claims 1 to 8, wherein the housing comprises at least one of polybutylene terephthalate, nylon 66, nylon 6T, nylon 9T, polyphenylene sulfide, and syndiotactic polystyrene.
10. The electrical connection member according to any one of claims 1 to 9, wherein the electrical connection member is configured as a terminal block for a motor.