JPH0137969Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electric power steering device for a vehicle that uses an electric motor as a power source in order to reduce the steering force of the vehicle's steering wheel. This relates to an electric clutch device.

Conventionally, electromagnetic clutches have been known as this type of clutch, but since the coefficient of friction of the friction plates is small, it is necessary to increase the area of the friction plates, which inevitably results in a large size.

The present invention aims to overcome this drawback and provide a compact and simple electric clutch in which the electric clutch device is installed in a transmission device that transmits the rotation of the electric motor to the output shaft.

The drawings showing embodiments of the present invention will be described below.

A steering gear assembly 1 mounted on a vehicle body is connected to an output shaft 11 via an intermediate shaft 7 having cross joints 5 at both ends. A steering column assembly 8 attached to the vehicle body with a bracket 6 rotatably supports an input shaft 10 and an output shaft 11, each having a steering wheel 9 attached to its upper end. A transmission device 2 is attached to the steering column assembly 8 and receives rotation of an electric motor 3 via a torque cable 4. The transmission device 2 includes a housing 30 on the input shaft side and a cover 31 on the output shaft side, which rotatably support the input shaft 10 and the output shaft 11 with two ball bearings 26, 27 and one ball bearing 29. , the housing 30 and the cover 31 are aligned and fitted with a spigot, and are connected by bolts (not shown). The input shaft 10 and the output shaft 11 are connected to a torsion bar 12 by two pins 13, and can be rotated relative to each other by twisting the torsion bar 12. It is supported by matched needle roller bearings 28 to ensure smooth relative rotation. This relative rotation of the input and output shafts is controlled by a stopper section 14 provided at the abutting section of both shafts.
The torsion bar 12 is restricted from being subjected to excessive torque. Fig. 3 shows the stopper part 14.
shows the structure of That is, two protrusions 32 are provided at the end of the input shaft 10 and fit into two notches 33 provided at the end of the output shaft 11 with a predetermined gap. After being allowed to rotate,
The protrusion 32 and the notch 33 are adapted to engage with each other. The input and output shafts 10 and 11 have flange portions 15 and 16 facing each other, and the flange portion 15 of the input shaft
Two pins 17 are press-fitted into the
A planetary gear 19 is rotatably fitted into the flange 16 of the output shaft, and two pins 18 protrude from both sides of the flange 16 and are press-fitted therein.
A planetary gear 20 is attached to the part protruding toward the input shaft 10 side of 8.
are rotatably fitted, and both planetary gears 1
9 and 20 mesh with a common sun gear 21. Sun gear 21 includes input shaft 10 and output shaft 11
The output shaft 11 is rotatably supported at the shaft portion between the flange portions of the output shaft 11 . Further, the planetary gear 19 of the input shaft 10 meshes with a ring gear 22 rotatably fitted into the housing 30, and the planetary gear 20 of the output shaft meshes with a ring gear 23 fitted non-rotatably with the housing 30. These constitute the first two planetary gear sets. A notch 34 is provided on the outer circumferential surface of the ring gear 22 on the input shaft side, and the spherical head of the pin 24 fits into the notch 34. The other end of the pin 24 is fitted and fixed into a hole 37 provided in the center of the spool 25, and the spool 25 is slidably fitted into a hole 39 provided in the housing 30 in a direction perpendicular to the input shaft 10. are doing. As shown in FIG. 4, the hole 39 is closed at both ends with a lid 83, and a spring 35 is interposed between the lid 83 and the spool 25, and the spring 35 is loaded with an appropriate set load. The spool 25 is held in a neutral position. Furthermore, a handle torque detection device 36 such as a potentiometer, differential transformer, pulse encoder, etc. that detects the position of the spool 25 and converts it into an electric signal is fixed to one end of the spool 25. The pin 85 inserted into and out of the handle torque detection device 36 passes through a hole provided in the lid 83. Note that reference numeral 38 in FIG. 4 is a hole provided in the housing 30 to allow movement of the pin 24.

Further, a planetary gear 41 is rotatably fitted into a portion of the pin 18 that is press-fitted into the flange portion 16 of the output shaft and protrudes toward the output shaft side, and a ring gear 40 that meshes with this is fixed to the housing 30 in a non-rotatable manner. , the sun gear 42 is rotatably supported on the outer periphery of the output shaft 11 and meshes with the planetary gear 41.

Further, a spline on the inner circumference of a carrier 43 is engaged with the sun gear 42, and two pins 44 are press-fitted into the carrier 43, and a planetary gear 45 is rotatably fitted into each of the pins 44. The planetary gear 45 includes a sun gear 46 and a ring gear 47.
are in mesh with each other, and these constitute the second two planetary gear sets. The sun gear 46 is the output shaft 11
The ring gear 47 is rotatably supported on the outer periphery of the housing 30 . A large number of recesses 52 having slopes as shown in FIG. 5 are provided on the outer periphery of the ring gear 47. As shown in FIG. .
Solenoid 5 fixed to the outer surface of the housing 30
A pin 54 driven by the housing 30
When the solenoid 53 is turned on and the pin 54 engages with the recess 52 as shown in the figure, the ring gear 47 cannot rotate relative to the housing 30 and the solenoid 53 is turned off, pin 54 is connected to spring 5
With the force of 5, the ring gear 47 escapes from the recess 52.
can be rotated. When the solenoid 53 is turned off and the pin 54 is released from the recess 52, the pin 5
4 turns off a contact 77 provided on the power line connecting the solenoid 53 and the power source. On the other hand, the sun gear 46 meshes with a spline on the inner surface of a reduction gear 48 rotatably supported on the output shaft 11 by a needle roller bearing 69, and rotates as a unit. The reduction gear 48 meshes with a small gear 49 provided on the reduction input shaft 84.
8 and the small gear 49 may be spur gears, helical gears, bevel gears, etc. that can be rotated forward and backward with high efficiency other than the worm and the worm wheel. The reduction input shaft 84 is rotatably supported in the housing 30 and cover 31 by two small-diameter ball bearings 50, and is connected to the electric motor 3 via the torque cable 4, so that the rotation of the electric motor is transmitted to the reduction gear 48 with little friction. . The rotation of the reduction gear 48 is transmitted to the ring gear 47 via the sun gear 46 and the planetary gear 45, but when the ring gear 47 is fixed by the solenoid 53, the planetary gear 45 rotates and revolves along the inner periphery of the ring gear 47. Rotate the carrier 43. carrier 43
The rotation of is transmitted to the sun gear 42,
The rotation of is transmitted to the planetary gear 41, but since the ring gear 40 is fixed to the housing 30,
The planetary gear 41 rotates and revolves along the inner periphery of the ring gear 40, transmits its rotation to the flange portion 16 of the output shaft, and rotates the output shaft 11. . ring gear 4
7 is not fixed by the solenoid 53, the ring gear 47 is rotated by the planetary gear 45, so the revolution of the planetary gear, that is, the rotation of the carrier 43 does not occur, and the rotation of the electric motor is caused by the output shaft 11.
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The electric clutch device of the present invention configured as described above utilizes a ring gear of a planetary gear set that decelerates and transmits the rotation of the electric motor to the input shaft, and a solenoid is attached to this ring gear, so it does not take up much space. This has the effect of reducing electricity consumption. Also,
If the motor continues to rotate in one direction and does not stop due to an electrical circuit failure, or if the motor locks up and becomes unable to rotate, if the ring gear attempts to rotate due to excessive torque, the slope of the recess will cause the cam to It acts as a torque limiter to push the pin back by overcoming the electromagnetic force of the solenoid, turning off the contact on the power line, turning off the electric clutch device, and switching the steering device from an inoperable electric to manual mode. , safety has been greatly improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a conceptual side view of an electric power steering device, FIG. 2 is an enlarged longitudinal sectional view of a transmission device, and FIG. 3 is a cross-sectional view of FIG. 2.
An enlarged cross-sectional view along the line, Fig. 4 is the − of Fig. 2.
FIG. 5 is an enlarged cross-sectional view taken along the - line of FIG. 2. Explanation of symbols, 1...Steering gear assembly, 2
... Transmission device, 3 ... Electric motor, 4 ... Torque cable, 8 ... Steering column assembly, 9 ... Steering wheel, 10 ... Input shaft, 11 ...
Output shaft, 12...Torsion bar, 17, 20,
41, 45... Planetary gear, 21, 42, 46...
Sun gear, 22, 23, 40, 47...Ring gear, 24...Pin, 25...Spool, 26,2
7,29,50...Ball bearing, 30...Ball bearing, 3
0... Housing, 31... Cover, 34... Notch, 35... Spring, 36... Handle torque detection device, 43... Carrier, 48... Reduction gear,
49... Pinion, 52... Recess, 53... Solenoid, 54... Pin, 55... Spring, 77... Contact.

Claims (1)

[Claims for Utility Model Registration] Used in an electric power steering device that transmits the rotation of an electric motor 3 to an output shaft 11 in order to reduce steering force; In the electric clutch device provided in the electric clutch device, the transmission device is rotatably supported on the output shaft,
a reduction gear 48 that is connected to the output shaft of the electric motor and transmits rotation of the electric motor; a first sun gear 46 that meshes with the reduction gear and is rotatably fitted to the output shaft; and the first sun gear. The first planetary gear 4 that meshes
5, a first ring gear 47 that meshes with the first planetary gear and is rotatably and stopably fitted into the housing 30 that supports the output shaft via a bearing; and a first ring gear 47 that is provided on the first planetary gear. a carrier 43 that rotatably fits on the pin 44 and rotates around the output shaft integrally with the first planetary gear; a first gear that meshes with the carrier and rotatably fits on the output shaft; a second planetary gear 41 that meshes with the second sun gear and rotatably fits into a pin 18 provided on the flange portion 16 of the output shaft; , a second member non-rotatably fitted to the housing;
a ring gear 40; the electric clutch device includes a plurality of recesses 52 having slopes formed on the outer peripheral surface of the first ring gear; a pin 54 that can be engaged with and disengaged from the recesses; and the housing. a solenoid 53 which is fixed to the recess and urges the pin to engage with the recess during normal operation; and a solenoid 53 which overcomes the urging force of the solenoid and disengages from the recess in the event of an abnormality, turning off the power to the solenoid. An electric clutch device for an electric power steering device, comprising: a contact point 77 for bringing the clutch into a state of .