Bus bar unit

Abstract

To provide a bus bar unit capable of ensuring appropriate sealability.SOLUTION: A bus bar unit 1 comprises: a bus bar 2 having a first connection part 11 and a second connection part 12; and a holding member 3 which is formed integrally with the bus bar 2, and which has a columnar part 20 to be fitted into a mounting hole 42 on a wall part 41 for separating a first space 31 from a second space 32. The columnar part 20 has: a first sealing member 4A, provided on the first space 31 side, which seals between an outer peripheral surface 20a of the columnar part 20 and an inner peripheral surface 42a of the mounting hole 42; and a second sealing member 4B, provided on the second space 32 side, which seals between the outer peripheral surface 20a of the columnar part 20 and the inner peripheral surface 42a of the mounting hole 42. The first sealing member 4A and the second sealing member 4B are made of materials different from each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a bus bar unit. [Background technology]

[0002] Among conductive bus bar units installed in vehicles, there are some that are provided on a wall that separates an internal space exposed to oils and grease from an external space through which the outside air flows. Such bus bar units are required to have a seal between the internal space and the external space (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-161647 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional bus bar units described above use oil-resistant acrylic rubber as a sealing material to ensure a seal between the internal and external spaces, but this seal may deteriorate at low temperatures. On the other hand, if silicone rubber is used as a sealing material, the seal may deteriorate in oil. Thus, there is room for improvement in bus bar units in terms of preventing deterioration of the seal in oil, at low temperatures, and at high temperatures.

[0005] An object of the present invention is to provide a bus bar unit that can ensure appropriate sealing properties. [Means for solving the problem]

[0006] In order to achieve the above object, a busbar unit according to the present invention comprises: a busbar formed of a conductive metal material and having electrical connection portions provided at both ends in the axial direction; and a retaining member integrally molded from an insulating resin material so that the connection portions are exposed relative to the busbar, the retaining member having a cylindrical portion that fits into a mounting hole in a wall portion that partitions a first space in which one of the connection portions is exposed and a second space in which the other of the connection portions is exposed, wherein the cylindrical portion comprises: a first seal member that is provided on the first space side in the axial direction and is attached to an outer peripheral surface of the cylindrical portion to seal between the outer peripheral surface and an inner peripheral surface of the mounting hole; and a second seal member that is provided on the second space side opposite the first seal member in the axial direction and is attached to the outer peripheral surface of the cylindrical portion to seal between the outer peripheral surface and the inner peripheral surface of the mounting hole, wherein the first seal member and the second seal member are formed from different materials. [Effects of the Invention]

[0007] The bus bar unit according to the present invention has an effect of ensuring appropriate sealing properties. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side view showing a schematic configuration of a bus bar unit according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing a schematic configuration of the bus bar unit according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing a schematic configuration of the bus bar unit according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments. That is, the components in the following embodiments include those that can be easily imagined by a person skilled in the art or those that are substantially the same, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention.

[0010] [Embodiment] As shown in Fig. 1, a busbar unit 1 according to the embodiment is assembled into a box-shaped housing 40 for use. The housing 40 is mounted on a vehicle such as an automobile, and contains liquid oils such as lubricating oil inside, as in a vehicle transmission or motor. The housing 40 is made of a metal material such as iron or aluminum. The busbar unit 1 is a relay connector that electrically connects the inside and outside of the housing 40.

[0011] In the following description, the illustrated X direction is referred to as the "axial direction X." The axial direction X corresponds to the extension direction of the busbar unit 1. In this embodiment, the axial direction X on the first space 31 side is referred to as the "first axial direction X1," and the axial direction X on the second space side opposite to the first axial direction X1 is referred to as the "second axial direction X2." The axial direction X will be described as extending along the vertical direction, for example, but is not limited to this. Furthermore, unless otherwise specified, the directions used in the following description will be described as directions in a state in which the busbar unit 1 is fixed to the housing 40.

[0012] The busbar unit 1 is assembled to the housing 40 by fitting into a mounting hole 42 provided in a wall portion 41 constituting the housing 40. The busbar unit 1 is electrically connected to a first mating terminal 45 disposed inside the housing 40 and a second mating terminal 46 disposed outside the housing 40. The wall portion 41 separates a first space 31, which is the interior of the housing 40, from a second space 32, which is the exterior. The first space 31 accommodates a vehicle transmission, a motor, and other components (not shown), and contains, for example, oils and greases such as lubricating oil. On the other hand, the second space 32 does not contain oils and greases, and allows outside air to flow through. This outside air may be cold or warm depending on, for example, changes in the vehicle environment. Thus, the first space 31 receives more heat from the vehicle's drive unit than the second space 32, and is therefore at a relatively higher temperature than the second space 32. The temperature of the first space 31 changes in response to changes in the driving state of the vehicle, and the temperature of the second space 32 changes in response to changes in the vehicle environment. Each part constituting the bus bar unit 1 will be described below.

[0013] As shown in Figure 2, the busbar unit 1 includes a substantially cylindrical busbar 2, a retaining member 3 formed on the busbar 2, an annular first seal member 4A and a second seal member 4B attached to the retaining member 3, and an annular rear holder 5 and a third seal member 6 interposed between the busbar 2 and the retaining member 3.

[0014] 3, the busbar 2 has a cylindrical main body 10 and a first electrical connection portion 11 and a second electrical connection portion 12 provided at both ends of the main body 10 in the axial direction X. The main body 10, the first electrical connection portion 11, and the second electrical connection portion 12 are integrally formed from a conductive metal material and extend in the axial direction X. The busbar 2 has a holding member 3 integrally molded such that the first electrical connection portion 11 and the second electrical connection portion 12 are exposed to the outside when the busbar unit 1 is not assembled to the housing 40.

[0015] 2, the main body 10 is a cylindrical portion located at the center of the busbar 2 in the axial direction X. The main body 10 has an outer peripheral surface 10a.

[0016] As shown in FIG. 1 , the first connecting portion 11 is exposed from the holding member 3 to the first space 31, and is a portion to which the first mating terminal 45 is physically and electrically connected. The first connecting portion 11 is located on the first axial direction X1 side of the first outer peripheral surface 13. As shown in FIG. 1 , the first mating terminal 45 is connected to the first connecting portion 11 from the first axial direction X1 side toward the second axial direction X2 side. The first connecting portion 11 is formed in a semi-cylindrical shape and has a through-hole 11a at its approximate center that penetrates in the radial direction of the first connecting portion 11. For example, the first mating terminal 45 is fastened to the first connecting portion 11 via a fastening member or the like that is inserted into the through-hole 11a.

[0017] As shown in Fig. 1, the second connection portion 12 is exposed from the holding member 3 to the second space 32, and is a portion to which the second mating terminal 46 is physically and electrically connected. The second connection portion 12 is located on the second axial direction X2 side of the second outer peripheral surface 14. The second mating terminal 46 is connected to the second connection portion 12 from the second axial direction X2 side toward the first axial direction X1 side. The second connection portion 12 is formed in a cylindrical shape, and a connection hole 12a into which a part of the first mating terminal 46 is inserted is provided on the end face on the second axial direction X2 side (see Figs. 2 and 3).

[0018] Next, the holding member 3 will be described. The holding member 3 is a member that fixes the bus bar 2 to the wall portion 41 of the housing 40 in an attached state in which the bus bar 2 is inserted into an attachment hole 42 provided in the wall portion 41. The holding member 3 is made of an insulating resin material. The holding member 3 electrically insulates the bus bar 2 from the wall portion 41 in the attached state.

[0019] The holding member 3 has a columnar portion 20, a flange portion 21, and a housing groove 22. The columnar portion 20, the flange portion 21, and the housing groove 22 are all formed in the bus bar 2 by insert molding.

[0020] The columnar portion 20 is a portion of the busbar unit 1 that is insert-molded with an insulating resin material so that the first connection portion 11 and the second connection portion 12 are exposed relative to the busbar 2. As shown in FIGS. 1 to 3, the columnar portion 20 extends in the axial direction X and is formed in a cylindrical shape with the busbar 2 as its central axis along the axial direction X. Two grooves, a first groove 23 and a second groove 24, that are recessed radially inward are formed in the columnar portion 20 over the entire circumference of the outer circumferential surface 20a.

[0021] The first groove portion 23 is provided on the first space 31 side (first axial direction X1 side) in the axial direction X. The second groove portion 24 is provided on the second space 32 side (second axial direction X2 side) opposite to the first groove portion 23 in the axial direction X.

[0022] As shown in FIGS. 1 to 3, the flange portion 21 is a portion formed to protrude in a direction perpendicular to the axial direction X from the end portion of the cylindrical portion 20 on the second axial direction X2 side. The flange portion 21 is a portion formed to have a substantially elliptical shape when viewed from the second axial direction X2 side of the cylindrical portion 20. As shown in FIG. 1, the flange portion 21 is fixed to a wall portion 41 of the housing 40. A fixing collar 9 is provided on the flange portion 21 radially outward from the accommodating groove 22 when viewed from the second axial direction X2 side. The flange portion 21 is fixed to the wall portion 41 of the housing 40 by bolts 8 via the collar 9 (see FIG. 1).

[0023] The accommodating groove 22 is formed at an end of the holding member 3 on the second axial direction X2 side and has an annular opening toward the second axial direction X2. The accommodating groove 22 accommodates the rear holder 5 and the third seal member 6. Specifically, the rear holder 5 and the third seal member 6 are accommodated in the accommodating groove 22 in the order of the third seal member 6 and the rear holder 5. That is, the third seal member 6 is located on the first axial direction X1 side of the accommodating groove 22, and the rear holder 5 is located on the second axial direction X2 side of the accommodating groove 22. The accommodating groove 22 has an inner circumferential surface 22a and a pair of through holes 22b that penetrate radially relative to the inner circumferential surface 22a. The pair of through holes 22b are formed radially opposite each other with the main body 10 of the busbar 2 sandwiched therebetween. When the rear holder 5 and the third seal member 6 are accommodated in the accommodating groove 22, a portion of the rear holder 5 is inserted into the pair of through holes 22b.

[0024] As shown in FIGS. 1 and 3 , the first seal member 4A is a member that seals between the wall portion 41 of the housing 40 and the holding member 3 when the busbar unit 1 is fitted into a mounting hole 42 provided in the wall portion 41. The first seal member 4A is provided on the first space 31 side in the axial direction X (the first axial direction X1 side), and is housed in the first groove portion 23 of the cylindrical portion 20. The cross-sectional shape of the first seal member 4A is circular. Acrylic rubber can be used for the first seal member 4A.

[0025] 1 and 3, the second seal member 4B is a member that seals between the wall portion 41 and the holding member 3 when the busbar unit 1 is fitted into the mounting hole 42 provided in the wall portion 41 of the housing 40. The second seal member 4B is provided on the second space 32 side (second axial direction X2 side) opposite to the first seal member 4A in the axial direction X, and is housed in the second groove portion 24 of the cylindrical portion 20. The cross-sectional shape of the second seal member 4B is circular. Silicon rubber can be used for the second seal member 4B.

[0026] The rear holder 5 prevents the third seal member 6 from falling out of the accommodating groove 22. The rear holder 5 is formed in an annular shape. The rear holder 5 has a pair of protrusions 5a formed to protrude radially outward at radially opposing positions passing through the central axis O of the rear holder 5. When the rear holder 5 is accommodated in the accommodating groove 22, the pair of protrusions 5a are inserted into a pair of through holes 22b provided in the inner circumferential surface 22a to lock the rear holder 5 to the holding member 3. By being locked by the holding member 3, the rear holder 5 restricts movement of the third seal member 6 toward the second axial direction X2, thereby preventing the third seal member 6 from falling out of the accommodating groove 22.

[0027] The third seal member 6 is provided on the second space 32 side in the axial direction X, and is interposed between the inner circumferential surface 22a of the accommodation groove 22 and the outer circumferential surface 10a of the main body 10 of the busbar 2 to seal between the busbar 2 and the holding member 3. The third seal member 6 can be made of acrylic rubber, silicone rubber, or fluororubber.

[0028] Next, the sealing performance between the bus bar unit 1 of this embodiment and the wall 41 of the housing 40 will be described. Conventional bus bar units use only one sealing member made of oil-resistant acrylic rubber. Acrylic rubber is oil-resistant and heat-resistant, but tends to have poor cold resistance. The oil resistance refers to the sealing performance of the sealing member in oil. The heat resistance refers to the sealing performance of the sealing member at high temperatures. The cold resistance refers to the sealing performance of the sealing member at low temperatures. For example, acrylic rubber can be used in a temperature range of -20°C to 150°C, while the environmental temperature required for a typical vehicle is -40°C to 150°C. Therefore, there is a risk that the sealing performance between the wall 41 and the holding member 3 in a fitted state will be reduced at low temperatures. On the other hand, when silicone rubber is used for the sealing member, the silicone rubber has heat resistance and cold resistance but poor oil resistance. Specifically, silicone rubber can generally be used in a temperature range of -50°C to 220°C, but there is a risk that its performance will be reduced if it swells with oils and fats.

[0029] Therefore, the bus bar unit 1 of this embodiment uses a first seal member 4A made of oil-resistant acrylic rubber and a second seal member 4B made of heat- and cold-resistant silicone rubber to ensure sealing performance in oil, at low temperatures, and at high temperatures. Here, low temperatures are, for example, temperatures close to -40°C, and high temperatures are, for example, temperatures close to 150°C. Acrylic rubber is oil- and heat-resistant but has low cold resistance, and therefore may lose sealing performance at low environmental temperatures. On the other hand, silicone rubber is heat- and cold-resistant but has low oil resistance. Therefore, the bus bar unit 1 uses acrylic rubber for the first seal member 4A to prevent loss of sealing performance in oil and at high temperatures, and silicone rubber for the second seal member 4B to prevent loss of sealing performance at low and high temperatures. In this way, the busbar unit 1 seals the gap between the outer surface 20a of the retaining member 3 and the inner surface 42a of the mounting hole 42 at two locations along the axial direction X, so that if sealing is achieved at any one location, it can prevent the intrusion of oil and the like due to pressure.

[0030] As described above, in the bus bar unit 1 according to this embodiment, the bus bar 2 is made of a conductive metal material and has the first electrical connection portion 11 and the second electrical connection portion 12 provided at both ends in the axial direction X. This allows the bus bar unit 1 to supply power from outside the housing 40 to a device such as a motor housed in the housing 40, for example.

[0031] In addition, the busbar unit 1 has a holding member 3 that is integrally molded from an insulating resin material so that the first connection portion 11 and the second connection portion 12 are exposed relative to the busbar 2, and has a cylindrical portion 20 that fits into a mounting hole 42 in a wall portion 41 that separates a first space 31 in which one first connection portion 11 is exposed from a second space 32 in which the other second connection portion 12 is exposed. This allows the busbar unit 1 to electrically insulate the busbar 2 from a housing 40 to which the busbar unit 1 is assembled.

[0032] In addition, in the busbar unit 1, the columnar portion 20 includes a first seal member 4A that seals between the outer peripheral surface 20a of the columnar portion 20 and the inner peripheral surface 42a of the mounting hole 42, and a second seal member 4B that seals between the outer peripheral surface 20a and the inner peripheral surface 42a of the mounting hole 42. The first seal member 4A is provided on the first space 31 side in the axial direction X, and the second seal member 4B is provided on the second space 32 side opposite the first seal member 4A in the axial direction X. As a result, the busbar unit 1 can improve the sealing performance between the outer peripheral surface 20a of the holding member 3 and the inner peripheral surface 42a of the mounting hole 42 compared to a conventional busbar unit provided with only one seal member.

[0033] In addition, the first seal member 4A and the second seal member 4B of the busbar unit 1 are formed from different materials. This allows the busbar unit 1 to prevent a decrease in sealing performance in oil, low temperature, and high temperature by using, for example, the first seal member 4A made of acrylic rubber, which is oil-resistant and heat-resistant, and the second seal member 4B made of silicone rubber, which is heat-resistant and cold-resistant. As a result, the busbar unit 1 can ensure proper sealing performance between the first space 31 and the second space 32.

[0034] In this busbar unit 1, the first seal member 4A has higher sealing performance in oil than the second seal member 4B, and the second seal member 4B has higher sealing performance at low temperatures than the first seal member 4A and higher sealing performance at high temperatures. The busbar unit 1 also has the first seal member 4A made of acrylic rubber and the second seal member 4B made of silicone rubber. With this configuration, the busbar unit 1 can prevent a decrease in sealing performance in oil, at low temperatures, and at high temperatures by using, for example, the first seal member 4A made of oil-resistant acrylic rubber and the second seal member 4B made of heat-resistant and cold-resistant silicone rubber in combination.

[0035] Furthermore, the first space 31 of the busbar unit 1 contains grease and oil and is placed at a relatively higher temperature than the second space 32. This allows the busbar unit 1 to be attached to a housing 40 that contains liquid grease and oil such as lubricating oil inside, such as a transmission or motor for a vehicle.

[0036] Although the busbar unit 1 of the above embodiment uses a first seal member 4A made of oil-resistant and heat-resistant acrylic rubber in combination with a second seal member 4B made of heat-resistant and cold-resistant silicone rubber, this is not limiting. The busbar unit 1 may use, for example, a first seal member 4A made of oil-resistant and heat-resistant acrylic rubber in combination with a second seal member 4B made of cold-resistant ethylene propylene rubber. Alternatively, the busbar unit 1 may use, for example, a first seal member 4A made of oil-resistant and heat-resistant fluororubber in combination with a second seal member 4B made of heat-resistant and cold-resistant silicone rubber. Alternatively, the busbar unit 1 may use, for example, a first seal member 4A made of oil-resistant and heat-resistant fluororubber in combination with a second seal member 4B made of cold-resistant ethylene propylene rubber.

[0037] In this way, in the busbar unit 1, the first seal member 4A may be formed of either acrylic rubber or fluororubber, and the second seal member 4B may be formed of either silicone rubber or ethylene propylene rubber.

[0038] The bus bar unit 1 may also use a first seal member 4A made of oil-resistant hydrogenated nitrile rubber and a second seal member 4B made of heat-resistant and cold-resistant silicone rubber in combination. In this way, the bus bar unit 1 may have the first seal member 4A made of hydrogenated nitrile rubber and the second seal member 4B made of silicone rubber.

[0039] In the busbar unit 1 of the above embodiment, the first seal member 4A has a higher sealing ability in oil than the second seal member 4B, but this is not limited thereto, and the first seal member 4A may have a higher sealing ability at low and high temperatures. In the busbar unit 1, the second seal member 4B has a higher sealing ability in low temperatures than the first seal member 4A, but this is not limited thereto, and the second seal member 4B may have a higher sealing ability in oil and high temperatures. In the busbar unit 1, the second seal member 4B has a higher sealing ability at high temperatures, but this is not limited thereto, and the first seal member 4A may have a higher sealing ability at high temperatures. [Explanation of symbols]

[0040] 1 Busbar unit 2 Busbar 3 Retaining member 4A First sealing member 4B Second sealing member 11 First connection part (connection part) 12 Second connection part (connection part) 20 Cylindrical part 21 Flange 22 Storage groove 23 First groove 24 Second groove 31 1st space 32 Second space 40 cabinets 41 Wall 42 Mounting hole

Claims

1. a bus bar formed of a conductive metal material and having electrical connection portions provided at both ends in an axial direction; a holding member that is integrally molded from an insulating resin material so that each of the connection portions is exposed relative to the bus bar, and that has a cylindrical portion that fits into a mounting hole in a wall that partitions a first space in which one of the connection portions is exposed and a second space in which the other of the connection portions is exposed, The cylindrical portion is a first seal member provided on the first space side in the axial direction, attached to an outer peripheral surface of the cylindrical portion, and sealing between the outer peripheral surface and an inner peripheral surface of the mounting hole; a second seal member provided on the second space side opposite the first seal member in the axial direction, attached to the outer circumferential surface of the cylindrical portion to seal between the outer circumferential surface and the inner circumferential surface of the mounting hole, The first seal member and the second seal member are Made of different materials A bus bar unit characterized by the above.

2. The first seal member is The sealing performance in at least oil is higher than that of the second sealing member, The second seal member is the sealing property is higher than that of the first sealing member at least at low temperatures; The first seal member and the second seal member are At least one of them has sealing properties at high temperatures The bus bar unit according to claim 1 .

3. The first seal member is It is made of either acrylic rubber or fluororubber, The second seal member is Made from either silicone rubber or ethylene propylene rubber The bus bar unit according to claim 1 or 2.

4. The first seal member is It is made of hydrogenated nitrile rubber, The second seal member is Made of silicone rubber The bus bar unit according to claim 1 or 2.

5. The first space is The oil and fat are contained in the second space, and the temperature of the second space is relatively high. The bus bar unit according to claim 1 .

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