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 columnar body part 10; a holding member 3 which is formed integrally with the bus bar 2, and which is disposed on a wall part 41 for separating a first space 31 from a second space 32; a second sealing member 6 which is provided on the second space 32 side with respect to an axial direction X, and which is interposed between a second inner peripheral surface 24 of the holding member 3 and a second outer peripheral surface 14 of the bus bar 2 so as to seal between the bus bar 2 and the holding member 3; and a dissimilar material-bonding part P which is provided on the first space 31 side opposite to the second space 32 with respect to the axial direction X, and which bonds a first inner peripheral surface 23 of the holding member 3 to a first outer peripheral surface 13 of the bus bar 2 so as to seal between the bus bar 2 and the holding member 3. The first outer peripheral surface 13 is made of a laser machined surface which is machined by laser processing. The dissimilar material-bonding part P is formed by directly bonding the first outer peripheral surface 13, forming the laser machined surface, to the first inner peripheral surface of the holding member.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 member to ensure sealing performance, but this may decrease at low temperatures. On the other hand, if silicone rubber is used as a sealing member, this may decrease in sealing performance in oil. Thus, there is room for improvement in bus bar units in terms of preventing a decrease in sealing performance 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 includes a busbar having a cylindrical main body portion made of a conductive metal material and electrical connection portions provided at both axial ends of the main body portion; a retaining member integrally molded from an insulating resin material so that the connection portions are exposed relative to the busbar, the retaining member being installed on a wall portion that separates 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; and a front retaining member provided on the second space side in the axial direction and interposed between a second inner peripheral surface of the retaining member and a second outer peripheral surface of the main body portion of the busbar. the bus bar and the holding member; and a dissimilar material joint portion provided on the first space side opposite the sealing member in the axial direction, joining a first inner circumferential surface different from the second inner circumferential surface of the holding member to a first outer circumferential surface different from the second outer circumferential surface of the main body portion of the bus bar to seal the bus bar and the holding member, wherein the first outer circumferential surface is formed by a laser-machined surface processed by laser processing, and the dissimilar material joint portion is formed by direct joining of the first outer circumferential surface constituting the laser-machined surface and the first inner circumferential surface of the holding member. [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. [Figure 4] FIG. 4 is a perspective view showing a schematic configuration of a bus bar in 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. Hereinafter, the members that make up the busbar unit 1 will be described.

[0013] As shown in FIG. 2, the bus bar unit 1 includes a bus bar 2, a holding member 3, a first seal member 4, a rear holder 5, and a second seal member 6.

[0014] As shown in Fig. 4, 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 connection portion 11, and the second 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 connection portion 11 and the second connection portion 12 are exposed to the outside when the busbar unit 1 is not assembled to the housing 40.

[0015] As shown in Figures 3 and 4, the main body 10 has an outer circumferential surface that includes a first outer circumferential surface 13 provided on one side of the axial direction X (first axial direction X1) and a second outer circumferential surface 14 provided on the other side of the axial direction X (second axial direction X2).

[0016] The first outer peripheral surface 13 is configured with a laser-machined surface 15 that is machined by laser machining. This laser-machined surface 15 is provided around the entire outer peripheral surface of the main body 10. For example, as shown in FIG. 4, the laser-machined surface 15 is formed by laser light L emitted from a laser irradiation device LM. A portion of the holding member 3 is directly bonded to the first outer peripheral surface 13 by insert molding, and the first outer peripheral surface 13 is not exposed to the first space 31.

[0017] The second outer peripheral surface 14 is a portion of the outer peripheral surface of the main body 10 that is located adjacent to the first outer peripheral surface 13 in the axial direction X and is exposed to the outside of the holding member 3 without being embedded in the holding member 3 when the above-mentioned insert molding is performed. In other words, the second outer peripheral surface 14 is located at a position different from the laser-machined surface 15, and other parts of the holding member 3 are not joined by insert molding. An annular rear holder 5 and an annular second seal member 6 are attached to the main body 10 so as to surround the entire circumference of the second outer peripheral surface 14. The second outer peripheral surface 14 faces the holding member 3 in the radial direction, with the rear holder 5 and the second seal member 6 interposed therebetween.

[0018] 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.

[0019] 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 second mating terminal 46 is inserted is provided on the end face on the second axial direction X2 side (see Figs. 2 and 3).

[0020] 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 through an attachment hole 42 provided in the wall portion 41. The holding member 3 is formed of an insulating resin material. Specifically, the holding member 3 is a portion that is insert-molded in the bus bar unit 1 using the insulating resin material so that the first connection portion 11 and the second connection portion 12 are each exposed to the bus bar 2. The holding member 3 electrically insulates the bus bar 2 from the wall portion 41 in the attached state.

[0021] The holding member 3 has a main body portion 20, a flange portion 21, an accommodating groove 22, a first inner circumferential surface 23, and a second inner circumferential surface 24. The main body portion 20, the flange portion 21, the accommodating groove 22, the first inner circumferential surface 23, and the second inner circumferential surface 24 are all formed on the busbar 2 by insert molding.

[0022] 1 to 3, the main body 20 extends in the axial direction X and is formed in a cylindrical shape with the busbar 2 as a central axis along the axial direction X. The main body 20 has a groove 20b formed on the outer circumferential surface 20a, the groove 20b being recessed radially inward along the entire periphery of the outer circumferential surface 20a.

[0023] 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 an end portion of the main body 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 main body 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).

[0024] 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 in the second axial direction X2. The accommodating groove 22 accommodates the rear holder 5 and the second seal member 6. Specifically, the rear holder 5 and the second seal member 6 are accommodated in the accommodating groove 22 in the order of the second seal member 6 and the rear holder 5. In other words, the second 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 inner circumferential surface of the accommodating groove 22 is defined by a second inner circumferential surface 24. The accommodating groove 22 has a pair of through holes 25 that penetrate radially relative to the second inner circumferential surface 24. The pair of through holes 25 are formed to face each other in the radial direction with the main body 10 of the busbar 2 sandwiched therebetween. In a state in which the rear holder 5 and the second seal member 6 are housed in the housing groove 22, a part of the rear holder 5 is inserted into the pair of through holes 25.

[0025] The first inner peripheral surface 23 is directly bonded to the first outer peripheral surface 13 of the busbar 2. As shown in FIG. 3 , the first inner peripheral surface 23 is provided on the first axial direction X1 side. The first inner peripheral surface 23 is directly bonded to the first outer peripheral surface 13 of the busbar 2 by insert molding, thereby forming a dissimilar material joint P that seals between the busbar 2 and the holding member 3. That is, the dissimilar material joint P is formed by directly bonding the first outer peripheral surface 13, which constitutes the laser-machined surface 15, to the first inner peripheral surface 23 of the holding member 3. The dissimilar material joint P exhibits an anchor effect by forming minute irregularities on the laser-machined surface 15 by laser processing, and insert molding allows a resin material to penetrate into the irregularities. It is believed that providing the dissimilar material joint P between the busbar 2 and the holding member 3 increases and maintains the surface pressure between the first outer peripheral surface 13 and the first inner peripheral surface 23 due to the anchor effect, thereby exhibiting sealing properties.

[0026] The second inner circumferential surface 24 is a portion that faces radially the second outer circumferential surface 14 of the busbar 2. The second inner circumferential surface 24 forms a part of the accommodation groove 22, and faces the second outer circumferential surface 14 across the second seal member 6 when the rear holder 5 and the second seal member 6 are accommodated in the accommodation groove 22. The radial position of the second inner circumferential surface 24 is outward relative to the radial position of the first inner circumferential surface 23.

[0027] The first seal member 4 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 first seal member 4 is housed in a groove portion 20b provided in the main body portion 20. The first seal member 4 is made of various synthetic rubbers, such as silicone rubber, acrylic rubber, and fluororubber.

[0028] The rear holder 5 prevents the second 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 positions facing each other in the radial direction and 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 25 provided in the second inner circumferential surface 24 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 second seal member 6 in the second axial direction X2, thereby preventing the second seal member 6 from falling out of the accommodating groove 22.

[0029] The second seal member 6 is provided on the second space 32 side in the axial direction X, and is interposed between the second inner circumferential surface 24 of the holding member 3 and the second outer circumferential surface 14 of the main body 10 of the busbar 2 to seal between the busbar 2 and the holding member 3. The second seal member 6 can be made of acrylic rubber, silicone rubber, or fluororubber.

[0030] Next, the sealing performance of the bus bar unit 1 of this embodiment will be described. Conventional bus bar units use acrylic rubber for the second seal member. 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 seal member in oil. The heat resistance refers to the sealing performance of the seal member at high temperatures. The cold resistance refers to the sealing performance of the seal member at low temperatures. For example, acrylic rubber can be used in a temperature range of -20°C to 150°C, while the ambient temperature required for a typical vehicle is -40°C to 150°C. Therefore, the sealing performance between the bus bar 2 and the holding member 3 may be reduced at low temperatures. On the other hand, when silicone rubber is used for the second seal member, the silicone rubber has heat resistance and cold resistance but poor oil resistance. Specifically, silicone rubber generally has a usable temperature range of -50°C to 220°C, but its performance may be reduced by swelling with oils and fats.

[0031] Therefore, the busbar unit 1 of this embodiment provides an oil- and cold-resistant dissimilar material joint P between the busbar 2 and the holding member 3, and uses the dissimilar material joint P in combination with the second seal member 6 to ensure sealing performance in oil, at low temperatures, and at high temperatures. Here, low temperatures refer to temperatures close to -40°C, for example, and high temperatures refer to temperatures close to 150°C, for example. The dissimilar material joint P is oil- and cold-resistant, but its heat resistance is low, and sealing performance may be reduced at high environmental temperatures. Therefore, the busbar unit 1 provides the dissimilar material joint P to prevent deterioration of sealing performance between the busbar 2 and the holding member 3 in oil and at low temperatures, and the second seal member 6 prevents deterioration of sealing performance at high temperatures. In this way, the busbar unit 1 seals the busbar 2 and the holding member 3 at two locations along the axial direction X. Therefore, as long as sealing performance is achieved at any one of these locations, it can prevent the intrusion of oil or other contaminants due to pressure. Furthermore, the dissimilar material joint P will repeatedly exhibit sealing performance unless it is damaged, and even after its sealing performance has decreased at high temperatures, it will once again exhibit sufficient sealing performance when it returns to room temperature or low temperatures.

[0032] As described above, in the bus bar unit 1 according to this embodiment, the bus bar 2 has a cylindrical main body 10 made of a conductive metal material, 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. 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.

[0033] The busbar unit 1 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 retaining member 3 installed on 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.

[0034] The busbar unit 1 also has a second seal member 6 that is provided on the second space 32 side in the axial direction X and is interposed between the second inner peripheral surface 24 of the holding member 3 and the second outer peripheral surface 14 of the main body 10 of the busbar 2 to seal between the busbar 2 and the holding member 3. This allows the busbar unit 1 to ensure sealing between the inner peripheral surface of the mounting hole 42 of the housing 40 and the outer peripheral surface of the holding member 3.

[0035] The busbar unit 1 also includes a dissimilar material joint P, which is provided on the first space 31 side opposite the second seal member 6 in the axial direction X and joins a first inner circumferential surface 23, which is different from the second inner circumferential surface 24 of the holding member 3, to a first outer circumferential surface 13, which is different from the second outer circumferential surface 14 of the main body 10 of the busbar 2, to seal between the busbar 2 and the holding member 3. The first outer circumferential surface 13 is formed by a laser-machined surface 15 that is processed by laser machining. The dissimilar material joint P is formed by directly joining the first outer circumferential surface 13, which constitutes the laser-machined surface 15, to the first inner circumferential surface 23 of the holding member 3. This prevents deterioration of the sealing performance of the busbar unit 1 in oil, at low temperatures, and at high temperatures, ensuring appropriate sealing performance between the busbar 2 and the holding member 3.

[0036] Furthermore, in the busbar unit 1, the second seal member 6 is formed of a material that has higher sealing properties at high temperatures than the dissimilar material joint P. This allows the busbar unit 1 to maintain the sealing properties between the busbar 2 and the holding member 3 by the second seal member 6 even if the sealing properties of the dissimilar material joint P decrease at high temperatures.

[0037] 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, for example, in a vehicle transmission or motor.

[0038] In the above embodiment, the second seal member 6 is made of acrylic rubber, which has oil resistance and heat resistance, silicone rubber, which has heat resistance and cold resistance, or fluororubber, which has oil resistance and heat resistance, but is not limited to these. For example, the second seal member 6 may be made of ethylene propylene rubber when cold resistance is required. Furthermore, the second seal member 6 may be made of hydrogenated nitrile rubber when oil resistance is required. Furthermore, fluororubber may be used when heat resistance and oil resistance are required. [Explanation of symbols]

[0039] 1 Busbar unit 2 Busbar 3 Retaining member 4 First sealing member 6 Second seal member 11 First connection part (connection part) 12 Second connection part (connection part) 13 First outer peripheral surface 14 Second outer surface 15 Laser processed surface 20 Main body 23 1st inner peripheral surface 24 Second inner peripheral surface 31 1st space 32 Second space 40 cabinets 41 Wall

Claims

1. a bus bar having a cylindrical main body portion formed of a conductive metal material and electrical connection portions provided at both ends of the main body portion 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 to the bus bar, and that is installed on 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; a seal member provided on the second space side in the axial direction and interposed between a second inner peripheral surface of the holding member and a second outer peripheral surface of the main body portion of the bus bar to seal between the bus bar and the holding member; a dissimilar material joining portion that is provided on the first space side opposite to the seal member in the axial direction and joins a first inner circumferential surface of the holding member that is different from the second inner circumferential surface to a first outer circumferential surface of the main body portion of the bus bar that is different from the second outer circumferential surface, thereby sealing between the bus bar and the holding member, the first outer peripheral surface is configured as a laser-processed surface processed by laser processing, The dissimilar material joint is The laser-machined surface is formed by directly joining the first outer peripheral surface and the first inner peripheral surface of the holding member. A bus bar unit characterized by the above.

2. The sealing member is It is made of a material that has better sealing properties at high temperatures than the dissimilar material joint. The bus bar unit according to claim 1 .

3. 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 or 2.

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