JP2002225646A - Wiring structure for suspension part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring structure for a suspension part, capable of protecting a power line against flying stones and preventing the lower sectional strength of a trailing arm. SOLUTION: The wiring structure for the suspension part comprises the power line wired in a trailing arm member body 2 in an approximately U-shaped cross section or a U-shaped portion 8 formed in the longitudinal direction of a lateral rod.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-wheel drive electric vehicle in which a drive motor is incorporated in a wheel, and a structure in which a power cable is wired from the vehicle body to the in-wheel motor. The present invention relates to a wiring structure of a suspension portion which can prevent a power cable from being subjected to metal fatigue due to vibrations therein and resulting in breakage or the like.

[0002] As shown in FIG. 7, an electric vehicle is a vehicle that can run using only the driving force of an electric motor 101.
As a power source to be supplied to the electric motor 101, a vehicle using a secondary battery (battery) is called an electric vehicle A in a narrow sense, a vehicle using an engine generator is called a series hybrid vehicle B, and a vehicle using a fuel cell is called a fuel cell vehicle C. I will. In FIG. 7, 102 is a wheel, 103 is a controller, 104 is a secondary battery, 201 is an engine,
02 is a generator, 301 is a hydrogen supply source, and 302 is a fuel cell.

[0003] As described above, an electric vehicle is a vehicle that can travel using only the driving force of a rotary electric motor, and as a power source to be supplied to the electric motor, a secondary battery, a fuel cell, and an internal combustion engine are used. Is defined as a vehicle using a generator, a solar cell, or the like using these, or a combination thereof. However, in the following description, an electric vehicle using only a secondary battery is considered, but a vehicle using a fuel cell, an internal combustion engine generator, or a solar battery as a power source is also included.

[0004]

2. Description of the Related Art An in-wheel drive system in which an electric motor is inserted into wheels has been proposed by the present inventor as one of the conventional driving systems for electric vehicles. This in-wheel drive system has the characteristics that the efficiency of energy transmission from the electric motor to the wheels is improved, the weight of the entire drive system is reduced, and the effective use space in the vehicle interior is expanded.
In this drive system system, two or three power lines are connected to supply power from the vehicle body. However, since the drive system is connected to the vehicle body through the suspension, the power lines are Causes rupture. In order to suppress the influence of this vibration, it was necessary to make the power line long enough so that the vibration did not substantially affect it.

Conventionally, as a similar technique, there is an example in which a wiring technique is applied to a three-link type suspension (also referred to as a trailing link type) among four-wheeled vehicle rear suspensions.

FIG. 8 is a rear view of a vehicle body showing a conventional automobile suspension structure, and FIG. 9 is a side view of the vehicle body showing a conventional automobile suspension structure.

[0007] This three-link suspension is shown in FIG.
As shown in FIG. 9 and the trailing arm 600 and the lateral rod 601, the axle shaft 602
Is supported on the body frame 603, and the coil spring 60
An axle shaft 602 is suspended by a shock absorber 4 and a shock absorber 605. A wiring harness connected to a wheel speed sensor detection unit provided on a brake device or an axle housing is wired to a trailing arm 600 used in the three-link type suspension.

FIG. 10 shows a conventional wiring structure of a suspension section. A steel pipe 608 is fixed to a side surface 606 of a trailing arm 600 by a bracket 607, and a wire harness 609 is passed through the steel pipe 608 from the vehicle body A side. The wiring is connected to the wheel speed sensor detecting section B. In addition, 610 is a bush with an outer cylinder attached to the bracket on the vehicle body frame side, and 611 is a bush with an outer cylinder attached to the bracket on the axle shaft side.

In the case of the conventional suspension structure as described above, a stepping stone or the like jumped up by the front wheels jumps on the trailing arm 600 portion of the rear wheel during traveling, and the stepping stones fall into the steel pipe 608 or the wire harness 609.
The steel pipe 608 or the wire harness 609
Could be damaged.

In order to solve this drawback, there is provided a wiring structure of a suspension portion for wiring along a trailing arm member provided between a vehicle body frame and an axle shaft. In some cases, a concave portion is formed along the concave portion and wiring is performed along the concave portion. Further, there is a configuration in which the cross-sectional shape of the concave portion is gradually reduced according to the inclination direction of the trailing arm member on the descending side.

FIG. 11 is a conceptual perspective view showing a wiring structure of a suspension portion of a conventional improved example, and FIG. 12 is a sectional view taken along line B of FIG.

In these figures, reference numeral 701 denotes a trailing arm member constituting a suspension of an automobile. The trailing arm member 701 is attached to brackets 703 on the vehicle body frame side on both sides of a long trailing arm member main body 702. Bush 704 with outer cylinder
And a bush 706 with an outer cylinder attached to the bracket 705 on the axle shaft side. The trailing arm member main body 702 is formed by pressing one long plate member into a hat shape by press molding, and a recess 708 is formed along the upper surface longitudinal direction of the trailing arm member main body 702. The recess 708 is formed such that its cross-sectional shape gradually becomes shallower in the downward inclination direction of the trailing arm member main body 702, and finally the recess 708 is flush with the upper surface near the bush 706 with an outer cylinder. Have been.

Further, reference numeral 709 denotes a wire harness connected to a wheel speed sensor detecting portion provided on the brake device or the axle housing.
Corresponds to the recess 70 of the trailing arm member main body 702.
8, clamps 710, 71 secured to both ends of the trailing arm member body 702 by welding.
1 is bent over the wire harness 709 and fixed. A clamp 712 attaches the wire harness 709 to the upper surface of the bracket 703.

With this configuration, even if the stepping stones caused by the flipping of the front wheels hit the trailing arm member main body 702, they do not hit the wire harness 709.
The stepping stone does not damage the wire harness 709.

Further, since the cross-sectional shape of the concave portion 708 is formed to be gradually shallower in accordance with the inclination direction of the trailing arm member main body 702 on the descending side, even when rainwater or the like enters the concave portion 708, the slope of the concave portion 708 is formed. Is discharged to the outside.

[0016]

However, in the above-mentioned improvement, the object is a thin wire of the order of a wire harness connected to the sensor, a power line of an electric vehicle, that is, a thick wire having a large cross-sectional shape, and having a heavy weight. Large current capacity,
It is not intended for wires with poor flexibility.

The present invention has been made in view of the above circumstances, and has as its object to provide a wiring structure of a suspension portion that can protect a power line from flying stones and the like and prevent a reduction in cross-sectional strength of a trailing arm. I do.

[0018]

According to the present invention, in order to achieve the above object, [1] a wiring structure of a suspension portion has a substantially U-shaped section.
A power line is wired inside a U-shaped portion formed in the longitudinal direction of the U-shaped trailing arm member or the lateral rod.

[2] In the wiring structure of the suspension section according to the above [1], a drain hole is formed at the bottom of the U-shaped section.

[3] In the wiring structure of the suspension section according to the above [1], a staple is locked at a predetermined position of an upper opening of the U-shaped section.

[4] In the wiring structure of the suspension section according to the above [1], a sun gear in which the reduction mechanism is attached to the rotating shaft of the electric motor, a planetary gear meshing with the sun gear, and a coaxial shaft with the planetary gear. A planetary gear of the next stage, and a ring gear meshing with the planetary gear of the next stage. An output shaft of the planetary gear or the ring gear is coupled to a mechanical rotating body for braking, and In a drive mechanism of an electric vehicle in which wheels are driven via a speed reduction mechanism by an electric motor having wheel hubs directly connected to a rotating body, a trailing arm member or a lateral rod for supporting the electric motor on a vehicle body. It is characterized by being used for.

[5] In the wiring structure of the suspension part, the trailing arm member or the lateral rod of the suspension part is insulated except for the power line connection part, and the trailing arm member or the lateral rod is used as a power supply path. And

[6] In the wiring structure of the suspension part, each arm of the double wishbone having the upper arm and the lower arm and the rod of the link mechanism are made of an electric conductor, and are connected via a bush of an electric insulator. It is characterized in that it is connected to the main body and the rod of each arm is used as a power supply path.

[7] In the wiring structure of the suspension section according to the above [6], the bush of the electric insulator is coaxially screwed between each of the arms, the rod and the Joint body.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a conceptual perspective view showing a wiring structure of a suspension portion (a trailing arm member formed by press molding) showing a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line A of FIG. Arm member body cross section)
FIG.

In these figures, reference numeral 1 denotes a trailing arm member constituting a suspension of an automobile. The trailing arm member 1 is attached to brackets 3 on the body frame side on both sides of a long trailing arm member main body 2. Bush 4 with outer cylinder and bracket 5 on motor side
, A bush 6 with an outer cylinder is provided.

In particular, according to the present invention, the trailing arm member body 2 is formed by pressing a single long plate member into a U-shape by press molding, and extends along the longitudinal direction of the trailing arm member body 2. U-shaped part 8 is formed. The U-shaped portion 8 is provided with a drain hole 7 on the bottom surface. The U-shaped portion 8 houses a plurality of power lines 9 connected to the in-wheel motor. The power line 9 is
The trailing arm member body 2 is movably pressed by resin staples 11-1 to 11-3 inside the U-shaped portion 8 and wired. 10 is the power line 9 and the bracket 3
The power line 9 is fixed to a position where bending does not occur most by a resin clamp attached to the upper surface.

The trailing arm member main body 2 is substantially U-shaped in cross section.
(1) The cross-sectional shape of the power line itself requires a considerable area, and a large space is required to receive it.

(2) Since the power line is heavy, it is greatly affected by the vibration of the vehicle. However, if the storage space is large, the frictional damage due to the vibration is reduced.

(3) Since the power line is not fixed so that a bending force acts thereon but is elastically supported by a resin staple, bending and breaking can be suppressed. In addition, since the power line is also supported by the elastic resin staple on the bracket, it is possible to perform wiring while suppressing bending and breakage.

The reason is as follows.

Next, a case where the power line 9 is wired will be described.

First, the U of the trailing arm member body 2
A power line 9 is wired along the inside of the shape 8. The staples 11-1 and 11-3 hold the power line 9 in such a manner that no excessive force is applied to the recesses (or through holes) 2A of the trailing arm member main body 2 while the power lines 9 are held. The staples 11-1, 11-2,
11-3 is locked to the trailing arm member main body 2.
Thereby, when the number of the power lines 9 is two or three, the power lines 9 can be collectively supported.

Further, as a second embodiment, a lateral rod (not shown) may also be formed in a U-shape to form a U-shaped portion, and a power line may be attached to the U-shaped portion.

In the third embodiment, the trailing arm member main body 2 itself is formed of a conductive material by insulating the portion except for the portion to which the power line is connected, and the portions other than the necessary electrical connection portion are covered with an insulating film in principle. Can also be configured.

As a result, even if the stepping stone caused by the front wheel splashing hits the trailing arm member main body 2, the power line 9
Therefore, the power line 9 is not damaged by the stepping stone. Further, since the drainage hole 7 is formed on the bottom surface of the U-shaped portion 8, even when rainwater or the like enters the inside of the U-shaped portion 8, it is discharged from the drainage hole 7. Further, when the trailing arm member main body 2 also serves as a conductive path, the power line can be omitted and breakage due to vibration of the power line can be prevented.

Next, an embodiment of an in-wheel type motor connected to a power line will be described with reference to FIG.

FIG. 3 is a conceptual diagram showing a drive system of an electric vehicle according to the present invention.

The drive mechanism 150 for the electric vehicle is an integrated unit mechanism combining the motor 200, the reduction gear mechanism 300, and the brake 400, and has the tire 500 mounted thereon. The motor 200 is a permanent magnet type AC motor. The casing 210 of the motor 200 is
An outer frame 211, an inner frame 212, an end ring 213, and an end plate 214 are provided.

The outer frame 211 is cylindrical and has a bracket 211a on the right side in the figure.
The inner frame 212 is a cylindrical member arranged concentrically inside the outer frame 211 and has a bracket 212a on the right side in the drawing. The outer frame 211 and the inner frame 212 are connected by bolting the bracket portion 211a and the bracket portion 212a. An end ring 213 is bolted to the left end surface of the outer frame 211, and an end plate 214 is bolted to the end ring 213. A stator 220 formed by a stator core 221 and a coil 222 is attached to the inner peripheral surface of the outer frame 211. A cylindrical rotor 2 is provided on the outer peripheral surface of the inner frame 212 via a motor bearing 230.
40 is rotatably mounted.

The rotor 240 is formed by a rotor core 241 and a permanent magnet 242. A rotating block 250 is bolted to the rotor core 241 and the rotating block 2
At the left end of 50, a rotation speed detector 260 is attached,
A shaft 270 is serrated on the right side of the rotating block 250. An alternating current is supplied to the coil 222 of the motor 200 through the cable 280, and the rotation speed signal detected by the rotation speed
3 is output.

The support rings 290 and 291 formed on the outer frame 211 are connected to the fulcrum of the suspension, and the drive mechanism 150 is mounted on the chassis of the electric vehicle.

The reduction gear mechanism 300 is constituted by a planetary gear mechanism, and reduces the rotation of the shaft 270 and transmits the rotation to the wheel shaft 410. In this case, the carrier 310 of the reduction gear mechanism 300 is serrated and coupled to the wheel axle 410 so as to transmit the rotational force while allowing the axial movement of the wheel axle 410. Further, the reduction gear mechanism 3
The outer diameter of 00 is larger than the inner diameter of the rotor 240.

The wheel axle tube 411 through which the wheel axle 410 passes is connected to the bracket portions 211a and 212a.
Fixed to. Then, the motor 200 and the brake 4
00, specifically, the bracket portion 212a of the inner frame 212 and the wheel shaft tube 4
The reduction gear mechanism 300 is disposed in a space surrounded by the reference numeral 11. Further, an end surface of the shaft 270 and an end surface of the wheel shaft 410 are pivotally supported by a pivot 412.

The brake 400 is a hydraulic brake using a drum. That is, a wheel hub 420 is bolted to the wheel shaft 410, and the wheel hub 420
Is provided with a brake drum 430 with bolts. A hub bearing 440 is interposed between the wheel axle tube 411 and the wheel hub 420. This brake 4
In 00, when the brake pedal is depressed and the hydraulic pressure rises, the brake shoe 402 is pushed out by the action of the wheel cylinder 401 and comes into contact with the brake drum 430, so that the brake operates.

The tire 500 is mounted on a rim 510 of the disk wheel 505. The rim 510 is connected to the brake drum 430 via a wheel disk of the disk wheel 505.

In the drive mechanism 150 described above, the motor 20
When the rotation of the rotor 240 is performed by driving the rotation of the rotor 0, the rotation is transmitted to the rotation block 250 and the shaft 270, reduced by the reduction gear mechanism 300, and transmitted to the wheel shaft 410.
As a result, the tire 500 and the brake drum 430 connected to the wheel shaft 410 rotate, whereby the electric vehicle runs.

Further, the reduction gear mechanism 300 is
0, a planetary gear that meshes with the sun gear, a next-stage planetary gear coaxial with the planetary gear, and a ring gear that meshes with the next-stage planetary gear.

The power line 9 shown in FIG. 1 and FIG. 2 is temporarily connected to the vehicle body frame from the battery via a power control device provided for each wheel, and then provided to the trailing arm member main body 2 or the lateral rod. The motor 200 is movably supported along the U-shaped portion 8 and is connected as a cable 280 to a cable terminal of the motor 200.

When the power line 9 is not used, the trailing arm member main body 2 or the lateral rod is insulated except for the connection portion, and the output of the power control device is connected to one end of the trailing arm member main body 2 or the lateral rod. Connect the cable and connect the cable from the other end to the terminal of the motor.

FIG. 4 is a schematic view of a suspension mechanism comprising a double wishbone according to a second embodiment of the present invention.

In FIG. 4, reference numeral 111 denotes a chassis (BBF);
112, 112 ', 113, 113' are hollow frames, 114, 114 'are front rear wheels, 115, 115' are front front wheels, 120, 120 'are suspensions (double wishbones), 121, 121' The first subframe, 122, 122 ', is the second subframe, 12
3, 123 'are cushioning members, 125 and 125' are lower arms, 126 and 126 'are upper arms, 106 and
106 ', 107, 107' are two fluid pneumatic cylinders, 1
16, 116 'are pipes and 117, 117' are reservoirs.

FIG. 5 is a schematic view of a wiring structure of a suspension portion composed of a double wishbone according to a third embodiment of the present invention, and FIG. 6 is a schematic diagram of a main portion of a wiring structure of the suspension portion, as shown in FIG. In the wiring structure of the suspension unit, the double wishbone is composed of an upper arm 520 and a lower arm 530, and the upper arm 520 is common to the first joint mechanism 521 and the first arm 522 made of an electric conductor. A joint mechanism 523, a second joint mechanism 521 ′, and a pair of arms including a second arm 522 ′ made of an electric conductor and a common joint mechanism 523 are provided.

On the other hand, the lower arm 530 includes a first joint mechanism 531, a first arm 532 and a common joint mechanism 533 made of an electric conductor, a second joint mechanism 531 ′, and an electric conductor. A pair of arms including a second arm 532 ′ and a common joint mechanism 533 are provided. Note that 524, 524 ', 5
34, 534 'are lead wires welded to the rod.

As shown in FIG. 6B, the wiring structure of the double wishbone is provided with a male screw 522A on the outer peripheral portion of the distal end of the cylindrical arm 522, and the male screw 522A is provided with an electric insulator. The female screw 525A formed on the inner peripheral portion of the cylindrical bush 525 is screwed into the male screw 525B formed on the outer peripheral portion of the cylindrical bush 525. The female screw 526A is screwed.

As shown in FIG. 6A, the cylindrical arm 522 is an electric conductor, and is connected to the junction 526 via a cylindrical bush 525 made of an electrical insulator. And the second arm 522, 522 'can be used as a power supply path.
2 can be connected to each electrical device (not shown) via a lead wire 524 to be welded.

With this configuration, the arm of the double wishbone can be used as a wiring (conductive path), and the bushing 525 of the electrical insulator is coaxially screwed between each arm and the Joint body. As a result, electrical insulation can be ensured, and the arm and the joint can be connected without deteriorating the mechanical strength.

The present invention is not limited to the above-described embodiment, and various modifications can be made based on the gist of the present invention, and these are not excluded from the scope of the present invention.

[0060]

As described above, according to the present invention, the following effects can be obtained.

(A) Even if the stepping stone due to the front wheel jumping hits the trailing arm member main body, it does not hit the power line, so that the stepping stone does not damage the power line.

(B) Since a drain hole is formed in the bottom surface of the U-shaped portion of the trailing arm member main body, rainwater and the like can be removed from the U-shaped portion.
Even if it enters the inside of the shape, it is discharged from the drain hole.

(C) Since the staple is locked at a predetermined position of the upper opening of the U-shaped portion, the power line is elastically supported by the staple, so that bending and breakage can be suppressed.

(D) When the trailing arm member body also serves as a conductive path, the power line can be omitted, and
Breakage due to vibration of the power line can be prevented from occurring.

(E) The arm of the double wishbone can be used as a wiring (conductive path).

(F) The bush of the electrical insulator is coaxially screwed between the rod of each arm and the main body of the joint, so that electrical insulation is ensured and the mechanical connection between the rod and the joint is made. Connection can be made without deteriorating the strength.

[Brief description of the drawings]

FIG. 1 is a conceptual perspective view showing a wiring structure of a suspension unit according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line A of FIG.

FIG. 3 is a conceptual diagram showing a drive system of an electric vehicle according to the present invention.

FIG. 4 is a schematic view of a suspension mechanism including a double wishbone according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram showing a wiring structure of a suspension section according to a third embodiment of the present invention.

FIG. 6 is a main part configuration diagram of a wiring structure of a suspension part according to a third embodiment of the present invention.

FIG. 7 is a diagram showing a basic configuration of an electric powered vehicle.

FIG. 8 is a rear view of a vehicle body showing a conventional automobile suspension structure.

FIG. 9 is a side view of a vehicle body showing a conventional automobile suspension structure.

FIG. 10 is a diagram showing a wiring structure of a conventional suspension unit.

FIG. 11 is a conceptual perspective view showing a wiring structure of a suspension portion of a conventional improved example.

FIG. 12 is a sectional view taken along the line B in FIG. 10;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Trailing arm member 2 Trailing arm member main body 2A Depression (or hole) of trailing arm member main body 3,5 Bracket 4,6 Bush with outer cylinder 7 Drain hole 8 U-shaped part 9 Power line (wire harness) 10 Clamps 11-1, 11-2, 11-3 Stapler 11-A Projection locking portions 106, 106 ', 107, 107' Both fluid pneumatic cylinders 111 Chassis (BBF) 112, 112 ', 113, 113' Hollow Frame 114, 114 'Front rear wheel 115, 115' Front front wheel 116, 116 'Pipe 117, 117' Reservoir 120, 120 'Suspension (double wishbone) 121, 121' First subframe 122, 122 ' Second sub-frame 123, 123 'Buffer member 125, 125', 52 Lower arm 126, 126 ', 530 Upper arm 150 Drive mechanism 200 Motor 210 Casing 211 Outer frame 211a, 212a Bracket part 212 Inner frame 213 End ring 214 End plate 220 Stator 221 Stator core 222 Coil 230 Motor bearing 240 Rotor 241 Rotor core 242 Permanent magnet 250 Rotating block 260 Rotation speed detector 263,280 Cable 270 Shaft 290,291 Support ring 300 Reduction gear mechanism 310 Carrier 400 Brake 401 Wheel cylinder 402 Brake shoe 410 Wheel axle 411 Wheel axle tube 412 Pivot 420 Wheel Hub 430 Brake drum 440 Hub bearing 500 Tire 505 Disc wheel 510 rim 521, 531 first joint mechanism 521 ′, 531 ′ second joint mechanism 522, 532 first arm (cylindrical arm made of an electric conductor) 522 ′, 532 ′ second arm 522 A 525B Male screw 523,533 Common joint mechanism 524,524 ', 534,534' Lead wire 525 Cylindrical bush 525A, 526A of electrical insulator Female screw 526 Joint part

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60L 11/18 B60L 11/18 A H02K 5/22 H02K 5/22 F-term (Reference) 3D001 AA17 AA18 BA03 BA07 DA04 3D035 DA03 5H115 PA08 PA15 PC06 PG04 PI14 PI16 PI17 PI18 PI22 PI29 PU10 QI07 RB08 TB03 UI32 UI38 UI40 5H605 AA02 AA04 AA13 BB05 BB10 CC06 CC09 EC04

Claims (7)

[Claims] 1. A wiring structure of a suspension part, wherein a power line is wired inside a trailing arm member having a substantially U-shaped cross section or a U-shaped part formed in a longitudinal direction of a lateral rod. Wiring structure of suspension part. 2. The wiring structure of a suspension part according to claim 1, wherein a drain hole is formed at a bottom of said U-shaped part. 3. The wiring structure of a suspension part according to claim 1, wherein a staple is locked at a predetermined position of an upper opening of said U-shaped part. 4. The wiring structure of a suspension section according to claim 1, wherein the reduction mechanism is a sun gear mounted on a rotating shaft of the electric motor, a planetary gear meshing with the sun gear, and a next stage coaxial with the planetary gear. And a ring gear that meshes with the next stage planetary gear. The output shaft of the planetary gear or the ring gear is connected to a mechanical brake rotating body, and the brake rotation In a drive mechanism of an electric vehicle in which wheels are driven via a speed reduction mechanism by an electric motor having a wheel hub directly connected to the body, used as a trailing arm member or a lateral rod for supporting the electric motor on a vehicle body. A wiring structure of a suspension part, characterized in that: 5. The wiring structure of a suspension part,
A wiring structure for a suspension section, wherein a trailing arm member or a lateral rod of the suspension section is insulated except for a power line connection section, and the trailing arm member or the lateral rod is used as a power supply path. 6. The wiring structure of a suspension part,
Each arm of a double wishbone having an upper arm and a lower arm and a rod of a link mechanism thereof are formed as an electric conductor, and are connected to the Joint body through a bush of an electric insulator, and power is supplied to each of the arms and the rod. A wiring structure of a suspension portion, wherein the wiring structure is used as a road. 7. The wiring structure of a suspension unit according to claim 6, wherein the bush of the electrical insulator is coaxially screwed between each of the arms, the rod, and the Jont body. Wiring structure.