Junction Box

Abstract

This invention can suppress the phenomenon of connectors being damaged by external forces. A junction box for connection with a fuel cell includes a frame, a connector protruding from the outer side of the frame, and a protective portion that protects the connector by covering at least a portion of the connector. The protective portion has a first protective portion opposite to at least a portion of the upper part of the connector and a second protective portion opposite to at least a portion of the side part of the connector.

Description

Technical Field

[0001] This disclosure relates to a junction box for use in connection with a fuel cell. Background Technology

[0002] Patent Document 1 discloses a high-voltage cable for connecting to a fuel cell stack used in a vehicle. A junction box for distributing power to electrical equipment mounted in the vehicle is connected to such a high-voltage cable.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-141636 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] Junction boxes are equipped with connectors for electrical connections to electrical equipment. Since high voltages are frequently applied to these connectors, there is a need for technology that can prevent damage to the connectors from accidental external forces.

[0008] means for solving problems

[0009] This disclosure can be implemented in the following ways.

[0010] (1) According to one aspect of this disclosure, a junction box for connection with a fuel cell is provided. The junction box includes: a frame; a connector protruding from the outer side of the frame; and a protective portion that protects the connector by covering at least a portion of the connector, the protective portion having: a first protective portion opposing at least a portion of the upper part of the connector; and a second protective portion opposing at least a portion of the side part of the connector. According to this method, since the first protective portion opposes at least a portion of the upper part of the connector, it is possible to suppress the connector from being subjected to external force from the side opposing the upper part of the connector. Furthermore, since the second protective portion opposes at least a portion of the side part of the connector, it is possible to suppress the connector from being subjected to external force from the side opposing the side part of the connector. Therefore, it is possible to suppress the phenomenon of the connector breaking due to external force.

[0011] (2) In the above-described manner, the protective portion may also have a third protective portion, which is opposed to at least a portion of the connector end portion in the protruding direction of the connector. According to this embodiment, since the third protective portion is opposed to at least a portion of the connector end portion in the protruding direction of the connector, it is possible to suppress the connector from being subjected to external forces from the side opposite to the connector end portion.

[0012] (3) In the above-described manner, the first protective part, the second protective part, and the third protective part may also be configured to cover a portion of the electrical wiring connected to the connector, including the connection portion with the connector. According to this configuration, since the first protective part, the second protective part, and the third protective part cover a portion of the electrical wiring connected to the connector, including the connection portion with the connector, the first protective part, the second protective part, and the third protective part can protect the portion of the electrical wiring including the connection portion with the connector. Therefore, it is possible to suppress the phenomenon of damage to the portion of the electrical wiring connected to the connector due to external force. Furthermore, since no insulating material is provided in the portion of the electrical wiring including the connection portion with the connector, in a structure where the core wires of the electrical wiring are exposed, it is possible to suppress contact between other components and the exposed core wires.

[0013] (4) Alternatively, in the above embodiment, the frame may have a protrusion that protrudes from a position on the outer side surface different from the position where the connector protrudes, and the protective portion may have a fastening portion that is fastened to the protrusion. According to this embodiment, since the protective portion has a fastening portion that is fastened to the protrusion, when the protective portion is subjected to external force, the protective portion flexibly deforms starting from the protrusion, thereby effectively absorbing the external force. Therefore, the protective portion can adequately protect the connector.

[0014] (5) In the above-described manner, the protective part and the frame may also be electrically connected via the fastening part. According to this manner, the protective part and the frame are electrically connected via the fastening part, so that if the connector is damaged and the damaged connector comes into contact with the protective part, the current flowing from the connector to the protective part can flow to the frame via the fastening part. Attached Figure Description

[0015] Figure 1 This is a top view of the junction box mounted on the vehicle in this embodiment.

[0016] Figure 2 This is a perspective view of the connector installed in the frame in this embodiment.

[0017] Figure 3 This is a perspective view of the protective part in this embodiment.

[0018] Figure 4 It is along Figure 3 A cross-sectional view of the protective section cut off by the AA line.

[0019] Figure 5 This is a side view of the protective part in this embodiment.

[0020] Figure 6 It is along Figure 3A cross-sectional view of the protective section cut off by the BB line. Detailed Implementation

[0021] A. Implementation method:

[0022] A1. Overall structure of junction box 100:

[0023] Figure 1 This is a top view of the junction box 100 mounted on the vehicle VC in this embodiment. For ease of explanation, the direction along the travel direction of the vehicle VC is called the "front-rear direction", the vertical direction from the viewpoint of the driver riding in the vehicle VC is called the "up-down direction", and the left-right direction from the viewpoint of the driver riding in the vehicle VC is called the "left-right direction". The "front-rear direction", "up-down direction", and "left-right direction" are orthogonal to each other.

[0024] Junction box 100 is used to connect to a fuel cell (not shown). Junction box 100 distributes the power supplied from the fuel cell to electrical equipment (not shown) mounted on the vehicle VC, such as an air compressor, electric motor, and battery. The vehicle VC operates using the power supplied from the fuel cell.

[0025] like Figure 1 As shown, the junction box 100 is installed inside the front compartment FM located in front of the vehicle VC. Within the front compartment FM, numerous components are arranged in a layered, overlapping configuration in the vertical direction. The junction box 100 is positioned in the center of the front compartment FM in the horizontal direction, i.e., on the top layer of the front compartment FM. The fuel cell is installed on a lower layer than the junction box 100. The instrument panel DP is located behind the junction box 100.

[0026] Figure 2 This is a perspective view of the connector 20 installed in the frame 10 in this embodiment. Additionally, Figure 3 This is a perspective view of the protective part 30 in this embodiment. Figure 2 and Figure 3 As shown, the junction box 100 includes a frame 10, a connector 20, and a protective part 30. Additionally, in Figure 2 In the middle, the protective section 30 is omitted from the depiction.

[0027] <Frame 10>

[0028] The frame 10 is constructed primarily of aluminum. The frame 10 includes, but is not shown, fuses, bus wiring, etc., for distributing power supplied from the fuel cell. The power supplied from the fuel cell is delivered via the bus wiring to electrical equipment mounted on the vehicle's VC.

[0029] <Connector 20>

[0030] To supply power to the electrical equipment mounted in the vehicle's VC, a high voltage is applied to connector 20. For example... Figure 2 As shown, connector 20 protrudes rearward from the outer side 12 behind the frame 10. In this embodiment, two connectors 20 are arranged side by side in the left-right direction, and each connector 20 protrudes rearward from the outer side 12. Among the connectors 20, the connector 20 located on the left is referred to as "first connector 20a", and the connector 20 located on the right is referred to as "second connector 20b".

[0031] The connector 20 has an upper portion 21 facing upwards, a pair of side portions 22 consisting of a side portion 22 facing left and a side portion 22 facing right, and a rear portion 23 facing backwards. In this embodiment, the "rear portion 23" corresponds to the connector end portion 23 protruding in the protruding direction of the connector 20. Figure 2 As shown, electrical wiring EW is connected to the rear 23 of each connector 20. Details of the electrical wiring EW connected to the connector 20 will be described later.

[0032] In this embodiment, the upper portion 21 is the part that can be visually identified when viewing the connector 20 from above. Similarly, the side portion 22 is the part that can be visually identified when viewing the connector 20 from the left or right, and the rear portion 23 is the part that can be visually identified when viewing the connector 20 from the rear. Therefore, in a connector 20 that has partially rounded corners as in this embodiment, the areas of the upper portion 21 and the side portion 22 partially overlap.

[0033] <Protection Department 30>

[0034] The protective portion 30 protects the connector 20 by covering at least a portion of the connector 20. The protective portion 30 is provided as a component distinct from the frame 10. For example, the protective portion 30 is formed by shaping a plate-like material, such as steel, which possesses excellent toughness and ductility. The ductility and toughness of the material constituting the protective portion 30 are superior to those of the material constituting the frame 10.

[0035] like Figure 3 As shown, the protective portion 30 has a first protective portion 31, a second protective portion 32, and a third protective portion 33. The first protective portion 31, the second protective portion 32, and the third protective portion 33 form a continuous, smooth shape. The first protective portion 31 is located above the upper portion 21 of each connector 20 and is opposite to the upper portion 21. The second protective portion 32 is located to the left of the left side portion 22 of the first connector 20a and is opposite to the left side portion 22. Additionally, the second protective portion 32 is located to the right of the right side portion 22 of the second connector 20b and is opposite to the right side portion 22. The third protective portion 33 is located to the rear of the rear portion 23 of each connector 20 and is opposite to the rear portion 23.

[0036] like Figure 3As shown, the upper part 21 of connector 20 is configured to be visually indistinguishable from above due to the first protective part 31. Similarly, the left side 22 of the first connector 20a is configured to be visually indistinguishable from the left, and the right side 22 of the second connector 20b is configured to be visually indistinguishable from the right. The rear part 23 of connector 20 is configured to be visually indistinguishable from the rear due to the third protective part 33.

[0037] Furthermore, the first protective part 31 need not be opposite the entire upper part 21, but only at least a portion of the upper part 21. Similarly, the second protective part 32 can be opposite at least a portion of the left side 22 of the first connector 20a or the right side 22 of the second connector 20b, and the third protective part 33 can be opposite at least a portion of the rear part 23.

[0038] For example, in the event of a collision between a moving vehicle VC and an obstacle in front, assuming that in a structure without the protective portion 30, the connector 20 is subjected to a force from the instrument panel DP. This is because when the connector 20 is viewed from above or from the rear, the instrument panel DP has a portion overlapping the connector 20. In contrast, in this embodiment, since the connector 20 is protected by covering it with the protective portion 30, the phenomenon of the connector 20 breaking due to the force exerted on it by the instrument panel DP can be suppressed. Hereinafter, the protective portion 30 for properly protecting the connector 20 and the structure surrounding the protective portion 30 will be described in detail.

[0039] A2. Detailed structure of the protective section 30 and its surrounding area:

[0040] <Protective Structure of Electrical Wiring (EW)>

[0041] Figure 4 It is along Figure 3 A cross-sectional view of the protective portion 30 cut off by the AA line. (See attached image.) Figure 4 As shown, the electrical wiring EW connected to the rear portion 23 of each connector 20 extends downward from the rear portion 23 of each connector 20. Similar to the connector 20, a high voltage is applied to each electrical wiring EW. Therefore, it is preferable that each electrical wiring EW is also protected along with each connector 20. Regarding this, as... Figure 2 and Figure 4 As shown, the outer periphery of the electrical wiring EW is covered by a sheathing material CM made of insulating material. The sheathing material CM is fixed relative to the electrical wiring EW by insulating tape, thereby protecting the outer periphery of the electrical wiring EW. On the other hand, sometimes it is difficult to completely cover a portion of the electrical wiring EW with the sheathing material CM, including the connection portion with the connector 20. In this case, as in this embodiment, a portion of the electrical wiring EW including the connection portion with the connector 20 is exposed as the core wire BW not covered by the sheathing material CM.

[0042] The first protective part 31, the second protective part 32, and the third protective part 33 are configured to cover not only the connector 20, but also a portion of the electrical wiring EW, including the connection portion to the connector 20, namely the core wire BW portion not covered by the covering material CM. More specifically, the core wire BW of the electrical wiring EW connected to each connector 20 is covered by the first protective part 31, making it invisible from above, and is covered by the third protective part 33, making it invisible from behind. Similarly, the core wire BW of the electrical wiring EW connected to the first connector 20a is covered by the second protective part 32, making it invisible from the left side. Furthermore, the core wire BW of the electrical wiring EW connected to the second connector 20b is covered by the second protective part 32, making it invisible from the right side.

[0043] like Figure 4 As shown, in the third protection section 33, a curved portion 37 is provided at the end 36 on the opposite side of the connection portion between the first protection section 31 and the third protection section 33, bending in a direction away from the electrical wiring EW. In the event of a vehicle VC collision, if the protection section 30 deforms downwards, in a structure without the curved portion 37, there is a possibility that the end 38 at the end 36 of the third protection section 33 may come into contact with the electrical wiring EW. However, in this embodiment, by providing the curved portion 37, contact between the end 38 at the end 36 of the third protection section 33 and the electrical wiring EW can be suppressed. Therefore, phenomena such as damage to the electrical wiring EW can be suppressed, and the electrical wiring EW connected to the connector 20 can be properly protected.

[0044] <Structure of fastener 35>

[0045] like Figure 4 As shown, the frame 10 has a protrusion 14 that projects rearward from the outer side 12 at the rear of the frame 10. More specifically, the protrusion 14 projects rearward from a position above the position where it protrudes from the connector 20 on the outer side 12.

[0046] The protective part 30 has a fastening part 35 that is fastened to the protrusion 14. For example... Figure 3 and Figure 4 As shown, the protective part 30 is fastened to the frame 10 by inserting two screws SW from the rear of the protrusion 14. Furthermore, the protective part 30 and the frame 10 are electrically connected via the fastening part 35. In this case, if the surface of the protective part 30 or the frame 10 is coated with an insulating material, the protective part 30 can be electrically connected to the frame 10 by peeling off the coating from the portion in contact with the fastening part 35.

[0047] <Structure of the lower layer of the protective section 30>

[0048] Figure 5This is a side view of the protective part 30 in this embodiment. Figure 5 As shown, a space TS is provided between the protective part 30 and any lower component LP mounted on the lower side of the protective part 30. Therefore, even if the protective part 30 deforms downwards during a vehicle VC collision, damage to the protective part 30 or the lower component LP due to contact between the protective part 30 and the lower component LP can be suppressed. Thus, the protective part 30 can adequately protect the connector 20. Furthermore, it is preferable to set a lower limit and an upper limit for the distance DT between the protective part 30 and the lower component LP in the space TS. The lower limit can be set, for example, based on the assumed downward deformation of the protective part 30 during a vehicle VC collision.

[0049] The upper limit value can be set, for example, based on the amount of downward deformation of the protective part 30 assumed during a vehicle VC collision plus the average diameter of a human finger. Thus, when the protective part 30 deforms downward during a vehicle VC collision, it can prevent operators repairing the vehicle VC from inserting their fingers between the protective part 30 and the lower component LP.

[0050] Figure 6 It is along Figure 3 A cross-sectional view of the protective portion 30 cut off by the BB line. (See attached image.) Figure 6 As shown, the second protective portion 32 extends away from the connector 20 towards the side opposite to the connection portion between the second protective portion 32 and the first protective portion 31. That is, the second protective portion 32 on the left extends away from the connector 20 in a downward direction to the left. Similarly, the second protective portion 32 on the right extends away from the connector 20 in a downward direction to the right. Thus, even if the protective portion 30 contacts the lower component LP during a vehicle VC collision, the second protective portion 32 expands and deforms away from each connector 20. Therefore, it is possible to more effectively suppress damage to the protective portion 30 or the lower component LP due to contact between the protective portion 30 and the lower component LP.

[0051] According to the junction box 100 described above, since the first protective part 31 is opposed to at least a portion of the upper part 21 of the connector 20, it is possible to suppress the connector 20 from being subjected to external force from the side opposite to the upper part 21 of the connector 20. Furthermore, since the second protective part 32 is opposed to at least a portion of the side part 22 of the connector 20, it is possible to suppress the connector 20 from being subjected to external force from the side opposite to the side part 22 of the connector 20. Therefore, it is possible to suppress the phenomenon of the connector 20 breaking due to external force. In addition, since the protective part 30 has the second protective part 32, the rigidity of the protective part 30 is improved. Therefore, when the protective part 30 is subjected to impact, it is possible to prevent the protective part 30 from deforming excessively and coming into contact with the connector 20.

[0052] To suppress impacts on the connector 20, a structure could be considered where ribs, as part of the frame 10, are provided around the connector 20 instead of the protective portion 30. However, in this structure, the external force borne by the ribs is directly transmitted to the frame 10, which could cause deformation of the frame 10. On the other hand, in this embodiment, the protective portion 30 is provided as a separate structure from the frame 10, thus suppressing deformation of the frame 10 even when an external force is applied to the protective portion 30.

[0053] Furthermore, since the third protective part 33 is opposite to at least a portion of the connector end part 23 protruding in the protruding direction of the connector 20, it is possible to suppress the external force on the connector 20 from the side opposite to the connector end part 23.

[0054] The first protective part 31, the second protective part 32, and the third protective part 33 are configured to cover a portion of the electrical wiring EW connected to the connector 20. This portion includes the connection portion with the connector 20, thus protecting the portion of the electrical wiring EW, including the connection portion with the connector 20, by the first protective part 31, the second protective part 32, and the third protective part 33. Therefore, it is possible to suppress the phenomenon of damage to the portion of the electrical wiring EW connected to the connector 20 due to external force. In addition, as in this embodiment, in the portion of the electrical wiring EW including the connection portion with the connector 20, a covering material CM made of insulating material is not provided. In the structure where the core wire BW of the electrical wiring EW is exposed, it is possible to suppress contact between other components and the exposed core wire BW.

[0055] Furthermore, since the protective portion 30 has a fastening portion 35 that is fastened to the protrusion 14, when the protective portion 30 is subjected to external force, the protective portion 30 flexibly deforms from the protrusion 14, thereby effectively absorbing the external force. Therefore, the protective portion 30 can properly protect the connector 20.

[0056] Furthermore, due to the collision of the vehicle VC, the connector 20 may be damaged and the damaged connector 20 may come into contact with the protective part 30. Even in this case, since the protective part 30 is electrically connected to the housing 10 via the fastening part 35, and the housing 10 is made of a metal material such as aluminum with low resistance, the current flowing from the connector 20 to the protective part 30 can flow to the housing 10 via the fastening part 35.

[0057] B. Other implementation methods:

[0058] (B1) In this embodiment, the junction box 100 is disposed in the center of the front compartment FM in the left-right direction and on the top layer of the front compartment FM, but this disclosure is not limited to this. The junction box 100 may be mounted on the lower layer of the front compartment FM, or it may be mounted on the lower part of the vehicle body instead of the front compartment FM. In addition, the junction box 100 is not limited to being mounted on the vehicle VC, and can also be used for various purposes such as branching electrical wiring EW.

[0059] (B2) In this embodiment, the connector 20 is disposed rearwardly from the outer side 12 at the rear of the housing 10, but this disclosure is not limited thereto. The connector 20 may be configured to protrude from the right, left, front, top or bottom of the housing 10.

[0060] (B3) In this embodiment, two connectors 20 protrude side by side from the outer side 12 of the frame 10 in the left-right direction, but this disclosure is not limited to this. For example, one or more connectors 20 may protrude from the frame 10. In addition, the frame 10 may have multiple connectors 20 protruding in different directions, such that one connector 20 protrudes from the rear of the frame 10, while another connector 20 protrudes from the right side of the frame 10.

[0061] (B4) In this embodiment, the connector 20 has partially rounded corners, causing the ranges of the upper portion 21 and the side portion 22 to partially overlap, but this disclosure is not limited to this. The connector 20 can take various shapes, such as prism or cylinder. For example, in the case of a cylindrical connector 20, the range of the left half of the upper portion 21 overlaps with the range of the upper half of the side portion 22 facing to the left. Similarly, the range of the right half of the upper portion 21 overlaps with the range of the upper half of the side portion 22 facing to the right. In addition, in a cylindrical connector 20, the upper portion 21 and the side portion 22 can also be defined such that their ranges do not overlap. For example, the connector 20 can be evenly divided into four parts with a central angle of 90 degrees, and a portion of the division can be defined as the upper portion 21 or the side portion 22.

[0062] (B5) In this embodiment, it is assumed that in the event of a collision between the moving vehicle VC and an obstacle in front, the connector 20 is subjected to force from the dashboard DP located behind and above the connector 20, but this disclosure is not limited to this. For example, it is assumed that in the event of a side collision between the vehicle VC and an obstacle, the connector 20 is subjected to force from components located to the side of the connector 20. The second protection part 32 can appropriately protect the connector 20 by suppressing external forces received from the side of the connector 20. In addition, this disclosure can be applied to various situations in which the junction box 100 may be impacted.

[0063] (B6) In this embodiment, the first protective portion 31, the second protective portion 32, and the third protective portion 33 are formed in a smooth, continuous shape, but this disclosure is not limited thereto. The first protective portion 31, the second protective portion 32, and the third protective portion 33 may each be formed independently. In this case, for example, the first protective portion 31, the second protective portion 32, and the third protective portion 33 may each be fastened to a portion of the frame 10.

[0064] (B7) In this embodiment, the second protective part 32 covers the first connector 20a from the left and the second connector 20b from the right. That is, the second protective part 32 covers the connector 20 from either the left or right direction, but this disclosure is not limited to this. The second protective part 32 may also cover the connector 20 from both the left and right directions relative to the connector 20.

[0065] (B8) In this embodiment, the protective part 30 has a third protective part 33, but this disclosure may also omit it. For example, if it is assumed that the connector 20 is mainly subjected to external forces from the upward direction, the third protective part 33 covering the connector 20 from the rear can be omitted.

[0066] (B9) In this embodiment, a portion of the electrical wiring EW, including a portion of the connection to the connector 20, is exposed as the core wire BW, which is not covered by the covering material CM, but this disclosure is not limited thereto. The electrical wiring EW may also be configured such that it is completely covered by the covering material CM up to the portion including the connection to the connector 20, and the core wire BW is not exposed.

[0067] (B10) In this embodiment, the first protection part 31, the second protection part 32, and the third protection part 33 cover the core wire BW that is not covered by the covering material CM, but this disclosure is not limited thereto. For example, if the covering material CM is configured to completely cover a portion including the connection portion with the connector 20, and the core wire BW is not exposed, the first protection part 31, the second protection part 32, and the third protection part 33 may also not cover a portion of the electrical wiring EW.

[0068] (B11) In this embodiment, the frame 10 has a protrusion 14 that protrudes rearward from the outer side 12 at the rear of the frame 10, and the protective part 30 has a fastening part 35 that is fastened to the protrusion 14, but this disclosure is not limited to this. The protective part 30 may also be fixed to the frame 10 by any fixing unit without the protrusion 14. In addition, the protective part 30 may also be fixed to a component or the like that disposed around the periphery of the frame 10, which is different from the frame 10.

[0069] (B12) In this embodiment, the protective part 30 and the frame 10 are electrically connected via the fastening part 35, but this disclosure is not limited to this. For example, if the periphery of the protective part 30 is covered by an insulating material, the protective part 30 and the frame 10 may not be electrically connected.

[0070] (B13) In this embodiment, the protrusion 14 protrudes rearward from the upper part of the connector 20 on the outer surface 12, but this disclosure is not limited to this. The protrusion 14 may protrude rearward from a position different from the position protruding from the connector 20 on the outer surface 12. For example, it may protrude rearward from the lower, right, or left side of the connector 20 on the outer surface 12. Even in this case, the protective part 30 can flexibly deform from the protrusion 14 as a starting point, thereby effectively absorbing the external force received. Therefore, the protective part 30 can properly protect the connector 20.

[0071] This disclosure is not limited to the embodiments described above, and can be implemented in various structures without departing from its spirit. For example, in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects, the technical features in the embodiments corresponding to the technical features in the various methods described in the Summary of the Invention section can be appropriately replaced or combined. In addition, if a technical feature is not described as an essential technical feature in this specification, it can be appropriately deleted.

[0072] Explanation of reference numerals in the attached figures

[0073] 10…Frame, 12…Outer side, 14…Protrusion, 20…Connector, 20a…First connector, 20b…Second connector, 21…Upper part, 22…Side part, 23…Connector end (rear part), 30…Protective part, 31…First protective part, 32…Second protective part, 33…Third protective part, 35…Fastening part, 36…End, 37…Bend, 38…End, 100…Junction box, BW…Core wire, CM…Covering material, DP…Front bulkhead, DT…Distance, EW…Electrical wiring, FM…Front compartment, LP…Lower component, SW…Screw, TS…Space, VC…Vehicle

Claims

1. A junction box for connection to a fuel cell, wherein, have: Frame; The connector protrudes from the outer side of the frame; and The protective section protects the connector by covering at least a portion of it. The protective part has: The first protective part is opposite to at least a portion of the upper part of the connector; as well as The second protective part is opposite to at least a portion of the side of the connector.

2. The junction box according to claim 1, wherein, The protective portion has a third protective portion, which is opposite to at least a portion of the connector end portion protruding in the protruding direction of the connector.

3. The junction box according to claim 2, wherein, The first protection section, the second protection section, and the third protection section constitute a portion covering the electrical wiring connected to the connector, the portion including the connection portion connected to the connector.

4. The junction box according to claim 1, wherein, The frame has a protrusion that projects from the outer side at a position different from that of the connector. The protective part has a fastening part that is fastened to the protrusion.

5. The junction box according to claim 4, wherein, The protective part and the frame are electrically connected via the fastening part.

Images