JP2007066550A - Spiral cable unit, and steering system transfer ratio variable device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spiral cable unit without a knocking sound of a flexible flat cable. <P>SOLUTION: The spiral cable unit 70 has a stator portion 73 and a rotator portion 72, and a flexible flat cable 71 is housed in swirl shape between the stator portion 73 and the rotator portion 72. An elastic coating 76a is applied at a support plate 76 to which the flat flexible cable 71 contacts by gravity, thereby a knocking sound which is generated caused by vibration between the support plate 76 and the flexible flat cable 71 can be cushioned by the elasticity of the elastic coating. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention includes a stator portion to which one end portion of a flexible flat cable is fixed, and a rotator portion to which the other end portion is fixed, and the flexible flat cable is interposed between the stator portion and the rotator portion. The present invention relates to a spiral cable unit in which a cable is housed in a spiral shape, and a steering system transmission ratio variable device that changes a turning angle of a steered wheel with respect to a steering angle of a steering according to a driving situation.

This type of steering system transmission ratio variable device connects an actuator to a steering system of an automobile, and drives and controls the actuator according to the steering angle of the steering, the vehicle speed, and other driving information. It is the structure which changes a cutting angle according to a driving | running condition (for example, refer patent document 1). A flexible flat cable is housed in a spiral shape so that it can absorb the rotation difference of the number of rotations of the steering wheel (for example, left and right 2.5 rotations, total 5 rotations) to supply power to the actuator and transmit signals. A spiral cable unit is used (see, for example, Patent Document 2).
JP 2005-53446 A JP 2004-224308 A

Here, in the spiral cable unit, a clearance is provided between the flexible flat cable, the stator portion, and the rotator portion so that it can slide between the stator portion and the rotator portion. For this reason, when vibration is applied along the rotation axis direction of the rotator section, a striking sound (rattle sound) is generated between the flexible flat cable and the rotator section and between the flexible flat cable and the stator section. appear. Here, since the noise in the steering system transmission ratio variable device is directly transmitted to the driver via the steering system, even a small hitting sound is annoying to the driver.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a spiral cable unit that eliminates the hitting sound of a flexible flat cable and a steering system transmission ratio variable device using the spiral cable unit. It is to provide.

In order to achieve the above object, the present invention has a stator portion 73 to which one end portion 71s of the flexible flat cable 71 is fixed, and a rotator portion 72 to which the other end portion 71e is fixed. In the spiral cable unit 70 in which the flexible flat cable 71 is accommodated in a spiral shape between 73 and the rotator 72,
The spiral cable unit 70 is arranged with its axis XX inclined,
A technical feature is that an elastic coating 76a is applied to the surface 76 on which the flexible flat cable 71 abuts by gravity.

In the present invention, since the elastic flat coating is applied to the surface of the flexible flat cable that comes into contact with gravity, the elasticity of the elastic coating is generated due to vibration between the contacting surface and the flexible flat cable. The impact sound can be buffered. Further, sliding noise of the flexible flat cable that is always generated between the flexible flat cable and the contact surface can be reduced. Here, the flexible flat cable always slides on the contact surface, but the elastic coating firmly adheres to the contact surface and the surface is slippery. There is no peeling.

According to a second aspect of the present invention, the vibration-proof sheet is disposed on the opposite surface of the surface on which the flexible flat cable is abutted by gravity and has an elastic coating. The facing surface is separated from the flexible flat cable on the contact surface by its own weight (the clearance is large), and when the vibration is applied, the flexible flat cable is in contact with a large inertial force. become. By providing the anti-vibration sheet having a thick and large buffering force on the facing surface, it is possible to buffer the impact sound generated due to the vibration. Here, since the flexible flat cable does not always slide on the facing surface, the vibration-proof sheet is not peeled off by the flexible flat cable.

According to the third aspect of the present invention, the elastic coating is a fluorine-based coating including urethane beads, and can be firmly fixed to the abutting surface while having elasticity, so that the elastic coating can be peeled off by sliding of the flexible flat cable. Absent.

In claim 4, since the vibration-proof sheet is formed by coating urethane sheet with PET sheet, it is easy to increase the thickness and can have a large buffering force, and the flexible flat cable has a large inertial force. The striking sound generated due to the vibration can be buffered at the opposing surface that hits in the state. Since the slippery PET sheet is coated, it is possible to reduce the sliding noise of the flexible flat cable that is always generated.

According to claim 5, the elastic coating on the surface where the flexible flat cable abuts by gravity is applied on the vibration-proof sheet, and the elastic flat coating causes peeling even when the flexible flat cable always slides. In addition, the impact sound generated due to vibration can be minimized by the thick vibration-proof sheet.

Since the steering system transmission ratio variable device according to the sixth aspect includes the spiral cable unit of the present application, it is possible to buffer a striking sound generated in the steering system due to vibration during traveling of the vehicle.

[First embodiment]
A steering system transmission ratio variable device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram illustrating an overall configuration of a steering system transmission ratio variable device 10 according to an embodiment. The steering 12 is fixed to the steering shaft 14, and the steering shaft 14 is connected to the input side of an actuator 30 that changes the turning angle of the steering wheel 26 with respect to the steering angle in accordance with the driving situation. The actuator 30 includes a differential wave gear mechanism 40 and a servo motor 34 that drives the wave gear mechanism 40. The output side of the actuator 30 is connected to the pinion shaft 16, and the pinion gear 18 at the tip of the pinion shaft meshes with the rack 20. Tie rods 22, 22 extend from both ends of the rack 20, and these tie rods 22, 22 are connected to rotation support portions 24, 24 of the left and right steering wheels 26, 26.

FIG. 2 is a cross-sectional view of the actuator 30. In the actuator 30, a lock mechanism 38, a motor 34, and a wave gear mechanism 40 as a gear mechanism are provided in housings 52, 54, and 56 that are integrally coupled, and a spiral cable unit 70 is provided outside the housing 52. It has been. The spiral cable unit 70 includes a rotator 72 and a stator 73, and accommodates a flexible flat cable 71 in a spiral shape. The lower end 14a of the steering shaft 14 is connected to the housing 52 on the input side of the actuator 30 via the rotator 72 of the spiral cable unit 70, so that the housing 52 and the steering shaft 14 rotate as a unit. Yes. On the other hand, the upper end 16 a of the pinion shaft 16 is connected to the output side of the actuator 30.

The motor 34 has a motor housing 46 that is secured within a housing 54. The motor housing 46 includes a motor housing body 46a and a motor end plate 46b. The motor housing body 46 a has a cup shape with a shaft hole 46 c in the center, and is fixed to the housing 54. A motor end plate 46b is fixed to the steering shaft 14 side of the motor housing body 46a so as to close the opening of the motor housing body 46a. A stator 34S is fixed to the inner peripheral surface of the motor housing body 46a, and a rotor 34R that is rotationally driven by the stator 34S is provided in the stator 34S. A motor shaft 34A is fixed to the rotor 34R, and the motor shaft 34A projects in the axial direction at both ends of the rotor 34R. One end 34a of the motor shaft 34A is supported by a ball bearing 48 provided between the motor end plate 46b and the other end 34b of the motor shaft 34A is provided between the shaft hole 46c of the motor housing body 46a. It is supported by a ball bearing 58. Thereby, the motor shaft 34A can rotate coaxially with respect to the motor housing main body 46a and the housings 52, 54, and 56. One end 34 a of the motor shaft 34 </ b> A on the spiral cable unit 70 side can be fixed to the housings 52, 54, 56 by the lock mechanism 38. On the other hand, the other end 34 b of the motor shaft 34 A is connected to the wave gear mechanism 40.

The wave gear mechanism 40 is constituted by a harmonic drive (registered trademark). The wave gear mechanism 40 includes a wave generator 64 in which the other end 34b of the motor shaft 34A is fitted and can rotate integrally with the motor shaft 34A. The wave generator 64 includes a cam 64a having a substantially elliptical cross section perpendicular to the axis, and a ball bearing 64b provided on the outer periphery of the cam 64a. The inner ring of the bearing 64b is fixed to the outer periphery of the cam 64a, and the outer ring of the ball bearing 64b can be elastically deformed via the ball. An annular flexspline 66 that is elastically deformable integrally with the outer ring of the ball bearing 64b is provided on the outer periphery of the wave generator 64. External teeth 66 a are formed on the outer periphery of the flex spline 66. An annular stay circular spline 68 is formed on the motor 34 side in the housing 54. Inner teeth 68a having a greater number of teeth (102) than the number of teeth (100) of outer teeth 66a of flexspline 66 are formed on the inner circumference of stay circular spline 68, whereby stay circular spline 68 meshes with flex spline 66. ing. Further, an annular drive circular spline 69 is rotatably supported on the side of the pinion shaft 16 in the housing 54 adjacent to the stay circular spline 68 via a bearing metal 54a. On the inner periphery of the drive circular spline 69, the same number (100) of inner teeth 69a as the outer teeth 66a of the flexspline 66 are formed, so that the drive circular spline 69 is also meshed with the flexspline 66. A protective plate 67 is provided between the motor housing body 46 a and the wave gear mechanism 40. An upper end 16 a of the pinion shaft 16 is fixed to the drive circular spline 69.

That is, the housings 52, 54, and 56 are configured to rotate together with the steering shaft 14, and the rotation of the steering shaft 14 is 50/51 by the wave gear mechanism 40 composed of the above-described harmonic drive (registered trademark). The pinion shaft 16 is rotated. On the other hand, as described above, the rotation of the servo motor 34 is decelerated to (1/50) × (50/51) to rotate the pinion shaft 16. As the pinion shaft 16 is rotated by the servo motor 34, the turning angles of the left and right steering wheels 26, 26 are changed.

As shown in FIG. 1, the servo motor 34 of the actuator 30 is controlled by the ECU 80. The ECU 80 includes a CPU 82, an EEPROM 84, a ROM 86, a RAM 88, and a motor drive circuit 90 that drives the servo motor 34. The ECU 80 includes driving information such as the vehicle speed V from the vehicle speed sensor 92, the steering angle θss from the steering angle sensor 94 attached to the steering shaft 14, and the motor angle θm from the motor angle sensor 36 attached to the servomotor 34. Is captured. The ECU 80 drives the servo motor 34 such that the turning angle of the steered wheels 26 with respect to the steering angle θss of the steering wheel 12 changes according to the driving situation.

Here, power supply from the motor drive circuit 90 to the servo motor 34, transmission of the motor angle θm from the motor angle sensor 36, and the like are performed via the flexible flat cable 71 in the spiral cable unit 70. The configuration of the spiral cable unit 70 will be described in more detail with reference to the cross-sectional view of FIG.

The spiral cable unit 70 includes a rotator 72 having a fitting hole 72a for holding the lower end 14a of the steering shaft 14, and a stator 73. A terminal for connection to an external terminal is provided on the stator side. A terminal 74 is fixed, and a start end 71 s of a flexible flat cable 71 is connected to the terminal terminal 74. On the other hand, a connection terminal 75 is fixed to the rotator 72, and the terminal 71e of the flexible flat cable 71 is connected to the connection terminal 75, and a power line 75a is drawn to the servo motor 34 side.

The actuator 30 is disposed so as to be lowered forward from the steering 12 shown in FIG. 1 toward the pinion gear 18. That is, the spiral cable unit 70 shown in FIG. 3 is arranged so that the right side in the drawing is on the lower side. Here, on the flexible flat cable side wall of the rotator 72, a support plate 76 with an elastic coating 76a is disposed. The elastic coating 76a is made of, for example, a fluorine-based coating (thickness 5 to 20 μm) containing urethane beads (particle diameter 5 to 15 μm) or a molybdenum-based coating containing NBR rubber beads. On the lower support plate 76, the flexible flat cable 71 is in contact with its own weight.

On the other hand, an anti-vibration sheet 77 is affixed to the inner peripheral side of the standing wall of the stator portion 73 that becomes the opposing surface of the support plate 76. The anti-vibration sheet 77 has, for example, a thickness of about 0.8 mm and is formed by coating a PET sheet on urethane. A predetermined clearance (for example, about 1 mm) is provided between the flexible flat cable 71 that is in contact with the support plate 76 by its own weight and the vibration isolating sheet 77, and the flexible flat cable 71 is supported by the support plate. It is possible to slide on 76.

The flexible flat cable 71 is wound seven times in a spiral shape and is accommodated in the spiral cable unit 70. Here, the steering wheel 12 is set so that it can rotate 2.5 times in the left-right direction, for a total of 5 rotations. The spiral cable unit 70 has a flexible flat cable 71 arranged in a spiral shape on the support plate 76. Thus, the rotator 72 can be rotated in accordance with the rotation of the steering wheel 12 while the stator 73 is fixed.

On the other hand, when vibration during vehicle traveling occurs along the axis X of the spiral cable unit 70, the spiral cable unit 70 is shaken in the vertical direction, and the flexible flat cable 71 is connected to the support plate 76, the vibration isolation sheet 77, and the like. The collision will be repeated.

In the first embodiment, since the elastic coating 76a is applied to the surface of the support plate 76 against which the flexible flat cable 71 abuts by gravity, the support plate 76 and the flexible flat cable 71 are elastic due to the elasticity of the elastic coating 76a. The impact sound generated due to vibration can be buffered. Further, it is possible to reduce the sliding noise of the flexible flat cable 71 that is always generated on the support plate 76 due to the steering operation. Here, the flexible flat cable 71 always slides on the support plate 76 as the steering 12 rotates, but the elastic coating 76a is firmly fixed to the support plate 76, and the surface is smooth and slippery. The elastic coating 76a does not peel off due to the sliding of the flat cable 71.

The elastic coating 76a is a fluorine-based coating including urethane beads or a molybdenum-based coating including NBR rubber beads. The elastic coating 76a can be firmly fixed to the support plate 76a while having elasticity. Does not peel off due to movement.

In addition, a vibration-proof sheet 77 is disposed on the surface (the inner surface of the side wall of the stator portion) opposite to the surface on which the elastic coating 76a is abutted by the flexible flat cable 71 by gravity. The opposing surface is separated from the flexible flat cable 71 on the contact surface by its own weight (the clearance is large), and when the vibration is applied, the flexible flat cable 71 stores a large inertial force. You will win. By providing the anti-vibration sheet 77 having a large (for example, 0.8 mm) large shock-absorbing force on the facing surface, it is possible to buffer the impact sound generated due to vibration. Here, since the flexible flat cable 71 does not always slide on the vibration isolating sheet 77, the vibration isolating sheet 77 is not peeled off by the flexible flat cable 71.

Since the anti-vibration sheet 77 is formed by coating urethane with a PET sheet, by increasing the thickness of the urethane, it can be provided with a large cushioning force, and the flexible flat cable 71 has a large inertial force. The striking sound generated due to vibration can be buffered at the opposing surface (the inner surface of the stator side wall). In addition, since the urethane sheet is covered with slippery PET, it is possible to reduce the sliding noise of the flexible flat cable that is always generated in accordance with the steering operation.

Since the steering system transmission ratio variable device according to the first embodiment includes the spiral cable unit 70, it is possible to buffer a striking sound generated in the steering system due to vibration during traveling of the vehicle.

[Second Embodiment]
A steering system transmission ratio variable apparatus according to the second embodiment will be described with reference to FIG.
In the first embodiment described above with reference to FIG. 3, the elastic coating 76 a is directly applied on the support plate 76. On the other hand, in the second embodiment, the vibration-proof sheet 77 that has already been provided with the elastic coating 76 a is attached to the support plate 76.

In the second embodiment, the elastic coating 76a of the support plate 76 with which the flexible flat cable 71 abuts by gravity is provided on the vibration-proof sheet 77, and the flexible coating 76a is slid on the elastic coating 76a. Even if the flat cable 71 always slides, peeling does not occur, and the impact sound generated due to the vibration can be minimized by the thick vibration-proof sheet 77.

[Third embodiment]
A spiral cable unit 170 according to the third embodiment will be described with reference to FIG. In the first and second embodiments, the flexible flat cable is used for the steering system transmission ratio variable device. In contrast, in the third embodiment, a flexible flat cable is used to accommodate a signal line to the airbag.

FIG. 5 shows a cross section of a spiral cable unit 170 according to the third embodiment.
A flexible flat cable 171 is accommodated between the stator portion 173 and the rotator portion 172, the starting end 171s of the flexible flat cable is connected to the external terminal 174, and the end 171e of the flexible flat cable is the inner terminal. 175.

Also in the third embodiment, an elastic coating is applied to the surface where the flexible flat cable 171 comes into contact with its own weight, and a vibration-proof sheet is disposed on the surface facing the corresponding contact surface. The generation of a striking sound in 170 is prevented.

In the above-described embodiment, the case where the flexible flat cable is mounted on the vehicle has been described as an example. However, the flexible flat cable of the present invention is, for example, a machine tool such as a robot or a grinding machine, or a variety of It can also be applied to machines.

It is explanatory drawing of the steering system transmission ratio variable apparatus which concerns on 1st Embodiment of this invention. It is a partial broken view of an actuator. It is sectional drawing which expands and shows the spiral cable unit in FIG. It is a longitudinal cross-sectional view of the spiral cable unit which concerns on 2nd Embodiment. It is a cross-sectional view of the spiral cable unit according to the third embodiment.

Explanation of symbols

10 Steering System Transmission Ratio Variable Device 12 Steering 30 Actuator 34 Motor 40 Wave Gear Mechanism 70 Spiral Cable Unit 71 Flexible Flat Cable 71s Start End 71e End 72 Rotator 73 Stator

Claims (6)

The flexible flat cable has a stator portion to which one end portion is fixed and a rotator portion to which the other end portion is fixed, and the flexible flat cable is spirally formed between the stator portion and the rotator portion. In the spiral cable unit that can be accommodated,
A spiral cable unit characterized in that an elastic coating is applied to a surface of the flexible flat cable that abuts on the surface by gravity. 2. The spiral cable unit according to claim 1, wherein a vibration-proof sheet is disposed on a surface opposite to a surface on which the flexible flat cable comes into contact with gravity. The spiral cable unit according to claim 1 or 2, wherein the elastic coating is a fluorine-based coating containing urethane beads. 4. The spiral cable unit according to claim 2, wherein the vibration-proof sheet is formed by coating urethane sheet with PET sheet. The spiral cable unit according to any one of claims 1 to 4, wherein the elastic coating of the surface with which the flexible flat cable abuts by gravity is applied on a vibration-proof sheet. The spiral cable unit according to any one of claims 1 to 5,
A situation sensor for detecting a driving situation, a motor for supplying power via the spiral cable unit to change the turning angle of the steered wheels, an angle sensor for the motor, and the rotation of the motor are decelerated at a predetermined reduction ratio. A steering mechanism transmission ratio variable device that changes a turning angle of a steered wheel with respect to a steering angle of a steering according to a driving situation.

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