JPS6141670A - Motor-driven power steering gear - Google Patents

Abstract

PURPOSE:To dispense with a hydraulic control system and reduce the cost of production as well as to make improvements in fuel consumption, by driving a motor at a time when a speed displacement value in a shaft at the input side to that at the output side. CONSTITUTION:In time of running at low speed, tire reaction force operating a steering wheel 10 is large enough so that a torsion bar 15 is twisted in response to the operating force, making an input side shaft 11 into speed displacement to an output side shaft 14, whereby a detection pin 310 or 320 is displaced as far as the specified value from neutral, and a c.w./c.c.w. electric switch 31 or 32 operates. Since a ring gear 51 is engaged by a solenoid clutch 4, a planetary gear 52 rotates around a shaft 52a and simultaneously revolves inside the ring gear 51. Rotation of a motor M is transmitted to a sun gear bar 20 where a second gear 20b is engaged with the planetary gear, after being decelerated and further transmitted to a steering gear 12 via a universal joint 13.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electric power steering device.

(Prior Art) Conventionally, most of the power steering devices installed in automobiles are hydraulic type.

As such a hydraulic power steering device, 1
For example, there is one shown in FIG.

In other words, hydraulic power steering equipment.

High-pressure oil generated by high-pressure pump B driven by a belt by engine A enters power steering gear D via tAi & valve C, and the oil that has finished assisting enters oil tank E, which is connected to steering wheel F. When the is operated, a force corresponding to the tire reaction force acts on the power steering gear 0, a corresponding hydraulic opening is generated in the power steering gear D, a corresponding hydraulic pressure is generated, and this hydraulic pressure is applied to the power steering gear D. Both sides of the operating piston of the steering gear D are stiffened to reduce the operating force of the steering handle F.

(Problems to be Solved by the Invention) However, since such conventional power steering devices are hydraulic, the high pressure pump B, metering valve C1, oil tank E, high pressure piping, hoses, brackets, etc. There was a problem in that the cost was extremely high.

Furthermore, since the above-mentioned conventional putter steering device uses a flow control system, even when the steering wheel is not turned, the hydraulic pressure (3 to 5k) corresponding to the resistance of the metering valve C and the power steering gear D is applied.
g/am2), which causes a load on the engine, resulting in a reduction in output and fuel efficiency.

The present invention has been made in view of these problems, and an object of the present invention is to provide an electric power steering device that is inexpensive and does not adversely affect output or fuel efficiency.

(Structure of the Invention) The gist of the present invention is to provide an electric power supply system in which an input shaft connected to the steering handle side and an output shaft connected to the steering gear side are connected by a torsion bar. A steering device,
an operating force detection mechanism that detects a relative rotational displacement amount of the input shaft with respect to the output shaft according to an operating force of the steering handle, and operates an electric switch when the displacement amount reaches a predetermined value; a driving planetary gear mechanism having a ring gear and capable of decelerating the rotation of the motor and transmitting the rotation to the output shaft when the rotation of the ring gear is stopped; An electric power steering device comprising: an electromagnetic clutch that locks; and a control circuit that energizes the electromagnetic clutch and the motor when the electric switch is activated.

(Operation of the Invention) In the power steering device, when the input shaft is rotationally displaced by a predetermined amount in response to the operating force of the steering handle, the operating force detection mechanism operates the electric switch, When the switch is activated, the electromagnetic clutch locks the ring gear and the motor rotates, and the drive planetary gear mechanism decelerates the rotation of the motor and transmits it to the output shaft, thereby reducing the speed of the steering wheel. This is designed to reduce the operating force required.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

Figures w41 to 6 show an embodiment of the present invention.

As shown in FIG. 1, an input shaft 11 connected to the steering handle 10 side and an output shaft 14 connected to the steering gear 12 side via a universal joint 13 are connected by a torsion bar 15. .

The electric power steering device l assembled to the input side shaft) 11 and the output side shaft 14 calculates the relative rotational displacement amount of the input side shaft 11 with respect to the output side shaft) 14 according to the operating force of the steering handle 10. is detected, and when the amount of displacement reaches a predetermined value, the electric switch 31.
32, and a ring gear 51.
The drive planetary gear mechanism 5 is a drive planetary gear mechanism that can decelerate the rotation of the motor N and transmit it to the output shaft 14 only when the rotation of the motor N is stopped, and the rotation of the ring gear 51 is slowed down when energized. It consists of an electromagnetic clutch 4 that stops, and a control circuit that energizes the electromagnetic clutch 4 and the motor X when the electric switches 31 and 32 are activated.

As shown in FIGS. 1 to 4, the detection planetary gear mechanism 2 is integrally connected to the input shaft 11 and the torsion bar 15 by a knock pin P1. The three first planetary gears 22 mesh with the sun gear 21 and are rotatably supported by the shaft 22a, and are rotatable independently of the first planetary gears 22 by the shaft 22a. A knock pin P2 is attached to the supported second planetary gear 23, the output shaft 14, and the torsion bar 15.
The first gear portion 20a of the sun gear bar 20 and the shaft 22δ are integrally connected by the input side? A holding plate 24,25 that rotatably holds the shaft 11, a fixed ring gear 26 that meshes with the first planetary gear 22 and is fixed to the case 7 fixed to the vehicle body, and a second planetary gear 23. A spring member is installed between the engaged rotary ring gear 27, a protrusion 27a protruding from the rotary ring gear 27, and the case 7, and biases and holds the rotary ring gear 27 in the neutral position shown in FIG. It is composed of 28.29.

The electrical switch 31.32 has one end 310a, 32
0a is the detection bottle 31 fixed to the spring members 28, 28
0,320 is displaceably provided, and the detection bin 3
The electrical switch 31 or 32 is configured to operate when the switch 10 or 320 is displaced by a predetermined amount from the neutral position shown in FIG.

Electrical switches 31 and 32 and a speedometer 8 are connected to the control circuit 8, and when the electric switch 31 or 32 is activated and the vehicle speed is 10 km or less, a vehicle speed signal is output from the speedometer 8. The control circuit 6 is configured to energize the electromagnetic clutch 4 and the motor X when the signal is input.

As shown in FIGS. 1, 5, and 6, the driving planetary gear mechanism 5 includes a second gear portion 20b of the sun gear bar 20, three planetary gears 52 meshing with the second gear portion 20b, It is comprised of a ring gear 51 that meshes with a planetary gear 52 and is movable in the axial direction, and is attracted by the electromagnetic clutch 4 when energized and locked from rotation.

The shaft 7) 52a of the planetary gear 52 is the drive gear 9
1 to be rotatable around the sun gear bar 20, and the drive gear 81 meshes with a drive pinion 82 of the motor X.

The action will be explained below.

If you operate the steering handle 10 when the vehicle is stopped (stationary steering operation) or operate the steering handle 10 when the vehicle is running at an extremely low speed, the tire reaction force will be large, so the operation of the steering handle 10 will be difficult. The torsion member 15 is twisted in response to the force, and the input shaft 11 is rotationally displaced with respect to the output shaft 14.

As a result, when the sun gear 21 is rotationally displaced together with the input shaft 11, the first planetary gear 22 rotates on the shaft 22& together with the second Vi star gear 23, and rotates around the respective sun gears 21.25. The revolution speeds of the first and second planetary gears 22 and 23 are determined by the first planetary gear 22 on the fixed ring gear 2θ side, so the input shaft 11 and the output shaft The rotational displacement difference with the side shaft 14, that is, the decrease in the rotation of the second planetary gear 23 that occurs due to the relative rotational delay of the first gear portion 20a of the sun gear bar 20 with which the second planetary gear 23 meshes, It is corrected by the rotation of the rotating ring gear 27, and the 2'I! Due to the decrease in rotation of the star gear 23, the rotary ring gear 27 rotates from the neutral position shown in FIG.
10 or the detection pin 320 of the electric switch 32 is displaced against the biasing force of the spring member 28 or 28.

When the detection bin 310 or 320 is displaced from the neutral position by a predetermined amount, the electric switch 31 or 32 is activated.

When the electric switch 31 is activated and a vehicle speed signal output when the vehicle speed is 10 km/h or less is input from the speedometer 8, the control circuit 6 energizes the electromagnetic clutch 4 and rotates the motor X in the forward direction. let

Further, when the electric switch 32 is activated and the vehicle speed signal is input from the speedometer 8, the control circuit 6
energizes the electromagnetic clutch 4 and rotates the motor X in reverse.

The rotation of the motor X is caused by a drive pinion 82. The signal is transmitted to the planetary gear 52 of the driving planetary gear mechanism 5 via the drive gear 91 and the shaft 52a. At this time, since the rotation of the ring gear 51 is stopped by the electromagnetic clutch 4, the planetary gear 52 rotates around the shaft 52a and also revolves within the puffer gear 51.

Due to the revolution of the M star gear 52, the second gear portion 20b moves to t.
The rotation of the motor X is decelerated and transmitted to the sun gear bar 20 meshing with the star gear 52. As a result, the output shaft 14 rotates in the same direction as the operating direction of the steering handle 10, and this rotation is transmitted to the steering gear 12 via the universal joint 13.

That is, since the output shaft 14 is rotated by the motor X, the operating force of the steering handle 10 is reduced.

The electromagnetic clutch 4 is not energized when the electric switch 31 or 32 is not operating, or when the electric switch 31 or 32 is operating but the vehicle speed signal is not input to the control circuit 6. There is no motor X, and the motor X is not driven.

In this state, the operating force of the steering handle 10 is transmitted from the input shaft 11 to the output shaft 14 via the steering wheel. The planetary gear 52 and ring gear 51 of the planetary gear mechanism 5 only idle, and the planetary gear 52 does not revolve on the second gear portion 20b. Therefore, the drive gear 91 or the drive pinion 82 is not rotated and is not driven. The planetary gear mechanism 5-1 does not increase the operational resistance of the steering handle IO.

In addition, according to the above embodiment, it is possible to easily retrofit the steering shaft to a steering shaft connected by a torsion par, so that a manual steering vehicle can be easily converted into a power steering vehicle.

(Effect of the invention) According to the electric power steering device according to the present invention,
The motor is driven when the amount of rotational displacement of the input shaft relative to the output shaft reaches a predetermined value, and the rotation of the motor is decelerated by the drive planetary gear mechanism and transmitted to the output shaft, so that the hydraulic pressure is reduced. No control system required
Costs can be reduced and fuel efficiency will not be adversely affected.

[Brief explanation of drawings]

1 to 6 show one embodiment of the present invention, and the first embodiment is shown in FIG.
The figure is a partial sectional view showing the entire device, and Figure 2 is the same as Figure 1.
-II line sectional view, Figure 3 is a III-III line sectional view in Figure 1, Figure 4 is a ff-IV line sectional view in Figure 1, vg5 is a V-V line sectional view in Figure 1, The ti4S diagram is Vl in Figure 1.
-Vl line sectional view, FIG. 7 is a schematic diagram showing a conventional example. 1... Electric power steering device 2... Planetary gear mechanism for detection (operating force detection mechanism) 4... Electromagnetic clutch 5... Planetary gear mechanism for drive 6... Control circuit
10... Steering handle Fig. 1//') ζ−[σ Fig. 7

Claims (1)

[Claims] An electric power steering device in which an input shaft connected to a steering handle side and an output shaft connected to a steering gear side are connected by a torsion bar, and the output side corresponds to the operating force of the steering wheel. It has an operation force detection mechanism that detects the amount of rotational displacement relative to the shaft and operates an electric switch when the amount of displacement reaches a predetermined value, and a ring gear, and the rotation of the ring gear is a driving planetary gear mechanism capable of decelerating the rotation of the motor and transmitting it to the output shaft only when the motor is in a locked state; an electromagnetic clutch that locks the rotation of the ring gear when energized; and when the electric switch is activated. An electric power steering device comprising: the electromagnetic clutch and a control circuit for energizing the motor.