JPH03193557A - Electric power steering device - Google Patents

Abstract

PURPOSE:To omit a clearance adjustment between a clutch rotor and an armature as well as to shorten a span of assembling time by supporting the armature being selectively attracted to the clutch rotor so as to come into contact with the rotor side in a state of being free from slide motion in the axial direction. CONSTITUTION:A fixed side member comprising a field core 31 of a solenoid clutch 30 is installed at the side of a motor body 11b, while a clutch rotor 33 is installed at the side of a motor shaft 11a, and an armature 34 is installed at the side of a gear shaft 12 merely supporting it free of slide motion ion the axial direction. Accordingly, troublesome clearance adjustments for the clutch 30 becomes disused, so that in such a state as making the rotor 33 and the armature 34 contact with each other at all times, the side of the motor body 11b is merely fitted in the side of a steering body 6 for assembly whereby assembly of a motor 11 to the steering body side is performed. Consequently, assembling operability is sharply improvable. Next, the clutch 30 is normally used after being energized with current, and only when something wrong has occurred in output of the motor and a control system, speed transmission from the motor 11 to a steering output shaft system is interrupted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvement of an electric power steering device using an electric motor as a steering assist force generating means.

[Conventional technology]

In recent years, as a power steering device called power steering, an electric type that uses an electric motor etc. instead of a hydraulic type has been introduced as disclosed in Japanese Patent Application Laid-open No. 81-226382 and Japanese Patent Application Laid-open No. 84-4.
Various proposals have been made, including Publication No. 574. This kind of electric type results in an increase in the number of parts compared to a hydraulic type, and does not require various hydraulic parts, but simply connects the on-vehicle buffing system, controller, etc. and the electric motor with simple electrical wiring. In addition, the configuration of each part is simple and easy to manufacture.

It is easy to assemble, and the entire device can be made smaller and more compact.
It is possible to achieve cost reduction, etc.

In such an electric power steering device, the part where the electric motor is connected to the steering system via the reduction gear mechanism is equipped with ν3111 when power assist is not required, to prevent failures or malfunctions of the electric control system. In addition, an electromagnetic clutch is used to prevent the motor from being adversely affected by the impact force from the steering wheel when driving on a rough road, riding on a curb, colliding, etc. A structure having this configuration has been proposed in the past, for example, in Japanese Patent Application Laid-Open No. 1-115771.

[Problem to be solved by the invention]

By the way, in the conventional device using the electromagnetic clutch described above, when connecting the electric motor to the steering shaft, which is the main shaft of the steering system, via the electromagnetic clutch and the reduction gear mechanism for transmitting steering assist force, These motors, electromagnetic clutches, and small gears constituting the reduction gear mechanism were integrally connected. Therefore, in such a conventional structure, it is troublesome to adjust the gap between the clutch rotor and the armature using the electromagnetic clutch attached to the two motors, and to adjust the connection position between this clutch and the small gear of the reduction gear mechanism. Further, backlash adjustment work between the small gear constituting the reduction gear mechanism and the large gear on the steering shaft side becomes troublesome and complicated. In particular, the adjustment of the gap formed between the rotor and armature of the clutch mentioned above due to processing errors and assembly tolerances is 0.1 to 0.
．． It is a delicate adjustment of about 3cm, and it has a large impact on properly and reliably transmitting the steering assist force from the motor. Conventionally, the dimensions of the mounting part, etc. were measured during assembly work, and A troublesome and complicated adjustment is made by appropriately interposing shims between the mounting parts. However, such delicate adjustment work is a problem in terms of assembly workability, and in order to solve such problems, it is necessary to consider the configuration of each part and ease of assembly, and some countermeasures must be taken. It is hoped that this will be done.

[Means to solve the problem]

In order to meet such demands, the electric power steering device according to the present invention includes an electric motor that is connected to the steering output shaft system via a gear mechanism for transmitting steering assist force, and transmits rotational driving force when steering is necessary. , an electromagnetic clutch that is interposed in the gear mechanism from the motor to the steering output shaft system and selectively connects and interrupts rotation transmission between the motor side and a member on the gear shaft side having a transmission gear to the output shaft side. The fixed side member including the field core of this electromagnetic clutch is fixed to the motor main body side, and a clutch rotor magnetized by the field core is provided on the motor side, and tIi1
An armature that is selectively attracted to the clutch rotor is provided on the positive axis side and is supported so as to be able to freely slide in the axial direction and come into contact with the rotor bias.

[Effect]

According to the present invention, the fixed side member including the field core of the electromagnetic clutch is provided on the motor body side, and the armature can freely slide in the axial direction toward the gear shaft side in opposition to the clutch rotor provided on the motor side. By assembling the motor body in a state F8 such that the rotor and armature are in constant contact with each other, the motor body side is fitted to the steering body side that rotatably supports the gear shaft. At times, the two parts are integrated using magnetic attraction force to transmit rotation, and when not needed, the two parts are separated or slidable, preventing single rotation transmission. This eliminates the clutch rotor and armature that were previously required. This allows the gap adjustment to be omitted.

〔Example〕

1 and 2 show an embodiment of an electric power steering device according to the present invention. To explain simply with the drawings, 2 is a stub shaft as an input shaft connected to a steering wheel (not shown), and 3 is a pinion shaft as an output shaft having a pinion 3a connected to a steering wheel (not shown). , 4 is a torsion bar which connects these circular shafts 2.3 so that they can be relatively rotationally displaced within a predetermined angular range, and these constitute a steering shaft. The shaft 2.3 and the like constituting this steering shaft are disposed to pass through the steering gear body 6.7 together with a rack 5 having rack teeth 5a that mesh with the binion 3a, and rotate with the steering operation. Driven. In addition, 8a,
8b.

8c; 9a and 9b are pole bearings and needle bearings that rotatably support the shafts 3 and 2 within the body 6.7;
This is a bearing made by Butsch et al. Further, the rack 5 constitutes a steering link mechanism that connects the steered wheels together with a pitman arm, a tie rod, etc. (not shown).

In addition, in the steering shaft mechanism section, in the wooden embodiment, the stub shaft 2 on the steering handle side is provided with a torsion 8-4.
Through 1. A large gear 10 is provided on the pinion shaft 3 on the steering wheel side connected to the steering wheel side, and a large gear 10 for a transmitted tooth whose side surface on the input shaft 2 side is a tooth surface 10a is provided. An electric motor 11 that provides steering assist force to the side and a gear shaft that receives rotational transmission from the motor 11a [
2 is set approximately perpendicular to the pinion shaft 3 (a rotating shaft).

A small gear 12a is provided at the tip of the gear shaft 12, which is a transmission gear that constitutes a reduction gear mechanism that serves as a gear mechanism 13 for transmitting steering assist force together with the large gear 10.
The steering assist force from 1 can be transmitted to the pinion shaft 3 side. According to such a configuration, the electric motor 11 is directly connected to the gear body 6.7 having a steering shaft (2° 3.4), etc., and the pinion shaft 3 via a reduction gear mechanism including hypoid gears, bevel gears, etc. etc. can be efficiently connected, making it possible to make the entire device smaller, lighter, and more compact. In particular, in the hypoid gear of this embodiment, it is possible to reduce the size in the axial direction by the amount of the misalignment of the shafts.

On the other hand, the relative rotational displacement between the stub shaft 2 and the pinion shaft 3 due to the torsion of the torsion 8-4 is detected, and the motor 1
1 is a Hall element 1 provided on the pinion shaft 3 side as a non-contact torque sensor.
5, a magnet 16 provided on the stub shaft 2 side opposite thereto, and a printed wiring board 17 to which the Hall element 15 is attached and has a sensor signal processing circuit as a detection circuit thereof, and the detection signal is , which has a slip ring for output signal extraction integrally provided on the plate 17 and a brush (slider) in sliding contact with the slip ring, and is pulled out by a lead wire 18a from the brush holder 18, which serves as a signal extraction part, and has a connector at its tip. The connector member 19 is configured to be pulled out of the body 6 by a connector member 19 having a joint part 19a to which the parts are connected. The connector member 19 is configured to be removably screwed into the body 6 with an opening 6a formed in the body 6 closed with a sealing material in a watertight structure, and the joint portion 19a is provided inside the connector member 19. A lead wire 19b is attached that is electrically connected to and led out. Note that the detection mechanism 14 including a torque sensor etc. using the Hall element 15 and magnet 16 described above is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-115.
It has the same structure as that shown in Japanese Patent Publication No. 771+Jj, etc., and its detailed explanation will be omitted.

Further, reference numeral 20 denotes a steering angular velocity that detects the steering angle and its angular velocity based on the rotational displacement of the tip side of the pinion shaft 3, which is an output side member of the steering system that applies steering assist force to the steering wheel side in accordance with the steering operation. It is a sensor.

Now, according to the present invention, in the middle of the gear mechanism 13 consisting of the small gear 12a and the large gear 10 from the electric motor 11 that transmits the steering assist force to the pinion shaft 3 (output shaft system) which is the steering shaft on the steering wheel side. Interposed motor 11
It is equipped with an electromagnetic clutch 30 that selectively connects and interrupts rotation transmission between the a side and the gear shaft 12 side having a small gear 12a for transmission to the pinion shaft 3 side. A clutch housing 32, which is a fixed side member including a core 31, is fixed to the main body 11b side of the motor 11, and a clutch rotor 33 magnetized by the field core 31 is provided on the motor 11a side.
The armature 34, which is selectively attracted to the clutch rotor 33, is slid in the axial direction while being biased by a leaf spring 36 to a flange-like member 35 provided on the gear shaft 12 side so as to contact the clutch rotor 33. It is characterized by the fact that it is operable. Here, in the figure, 37 is a spline joint between the armature 34 and the 7-lung member 35, and 38 is a kite pin that connects these two members so as to be movable in the axial direction without rotating. Further, a stepped bearing hole 41 of six examples of steering bodies rotatably supports the gear shaft 12 via a pole bearing 39.40.
, the clutch housing 32 on the motor main body 11b side.
The cylindrical portion 32a is fitted and connected and fixed by spigot connection.

According to such a configuration, the fixed side member (housing 32) including the field core 31 of the electromagnetic clutch 30 is provided on the motor main body 11b side, and the motor 1
The clutch rotor 33 is provided on the 1a side, and the armature 34 is supported on the toothed east shaft 12 side so that it can simply slide in the axial direction.This eliminates the troublesome gap adjustment of the latch 30 as in the conventional method. becomes unnecessary. That is, by assembling the motor body 11b by fitting it into the steering body 6 side which rotatably supports the gear shaft 12 with a small wire, with the rotor 33 and the armature 34 always in contact with each other, Motor it to steering body side
Assembling can be carried out, and the ease of assembly work can be greatly improved. Moreover, the latch 30 like this is
Normally, it is used while being energized, and it is recommended to cut off rotation transmission from the motor 11 to the steering output shaft system (pinion shaft 3) only when an abnormality occurs in the motor output or motor control system, for example. At this time, it is sufficient to stop the power supply to the clutch 30 and set it to the OFF state, and there is no problem in operation even if the above-mentioned configuration is adopted.

That is, while the clutch 30 is in a state where rotation can be transmitted by magnetic attraction force when necessary, when the energizing current is turned off, the coupling force between the rotor 33 and the armature 34 is only the pressing force by the leaf spring 36. The space between the two is slidable, and the rotation of the motor 11 is hardly transmitted to the steering system, so that there is no problem in practical use.

Here, the one pole bearing 39 is of a four-point contact type that pivotally supports the gear shaft 12 in the thrust and radial directions. Also, 11c in the figure
42 is a ring-shaped plate material for locking and holding the pole bearing 39 that pivotally supports the gear shaft 12 in the stepped bearing hole 41, and the steering wheel is fixed by the screw 42a. It is fixed to the body 6 side. Furthermore, 43 has a 6-sided steering body due to the pilot connection. I! 44 is a set screw of the clutch housing 32 provided, and 44 is a small gear interposed between the stepped portion formed by the large diameter portion of the stepped bearing hole 41 and the pawl bearing 39 that is fitted and held therein. A shim 12a is used to adjust the contact with the teeth 10a of the large gear 10, and a shim 12b is recessed in the end face of the gear shaft 12 on the clutch side, and is used to adjust the rotation of the gear shaft 12 with an appropriate jig when assembling the device. In some cases, the small gear 12a and the large gear 1
This is an adjustment screw hole for backlash adjustment with the 0 side.

In the above-described configuration, the clutch rotor 33 is integrally fixed to the motor 11a, and the flange-like member 35 movably supporting the armature 34 is integrally fixed to the gear shaft 12 by key coupling or press fitting, although not shown. The electromagnetic clutch 30 and the motor 11 each have a well-known structure and perform a well-known operation, so a detailed explanation thereof will be omitted. Here, as the electromagnetic clutch 30 that selectively transmits the rotation from the motor 11 to the steering shaft side, the electromagnetic clutch 30 connects the motor 11 side and the steering system side only when steering is necessary.
By transmitting the steering assist force from to the steering shaft (3) side,! As a fail-safe in the event of an air system failure, etc., it can perform functions such as preventing deterioration of steering characteristics due to motor inertia and preventing damage to various parts due to impacts from the steering wheel side.

Furthermore, in the structure of the embodiment described above, although the configuration of each part is simple, it is difficult to assemble the gear mechanism 13 for transmitting steering assist force to the pinion shaft 3, the electromagnetic clutch 30, and the electric motor 11. Work and tooth contact and backlash adjustment in the gear mechanism 13 can be performed extremely easily, and
There are great advantages in assemblability, such as eliminating the need for adjustment work such as gap adjustment of the electromagnetic clutch 30, and making centering between the motor 11a side and the gear shaft 12 side easier.

FIG. 3 shows another embodiment of the present invention. In the embodiment described above, the armature 34 is pressed against the rotor 33 by the leaf spring 36 to actively eliminate the gap. , it goes without saying that the present invention is not limited to this. That is, the armature 34 is connected to the gear shaft 1.
It is preferable that the spline joint 37 or the like be provided on the second side so as to be slidable in the axial direction, and the movement range thereof is set to about θ to lam. Even with this configuration, the movement of the armature 34 does not pose any problem since the electromagnetic clutch 30 is always on when the vehicle is running and is attracted to the rotor 33. The advantages are huge.

FIG. 4 shows still another embodiment of the present invention, in which the structure of the joint between the electromagnetic crane notch 30 and the steering body 6 side is somewhat different, and a guide bin 50 for guiding the armature 34 in the axial direction is used. Although the case is shown in which the coil spring 51 is wound around the coil spring 51, the effect thereof is similar to that of the two embodiments described above, such as a substantially concave shape, and a detailed explanation will be omitted.

It should be noted that the present invention is not limited to the structure of the embodiment described above, and the shape and structure of each part may be modified and changed as necessary, and various modifications may be made, for example,
In the above-described embodiment, a hypoid gear is used as the filling mechanism 13 for transmitting steering assist force from the motor 11, but the present invention is not limited to this, and can be applied to other cars including Senken cars.

The gear mechanism 13 may be a helical gear, a planetary gear, a bevel gear, etc., and various modifications are possible.

〔Effect of the invention〕

As explained below, according to the electric power steering device according to the present invention, the electric motor is connected to the steering output shaft system via a gear mechanism for transmitting steering assist force and transmits rotational driving force when steering is necessary. and an electromagnetic device interposed in the gear mechanism from the motor to the steering output shaft system, which selectively connects and interrupts rotation transmission between the gear shaft side member having the transmission gear to the motor side and the output shaft side. A fixed side member including a field core of the electromagnetic clutch is fixed to the motor body side, a clutch rotor magnetized by the field core is provided on the motor side, and a clutch rotor is provided on the gear shaft side. Since the armature, which is selectively referred to as a prefecture, is supported so as to be in contact with the rotor side with a movable member that can freely slide in the axial direction, it is possible to transmit steering assist force despite the simple structure. When necessary, the clutch rotor and armature are integrated by magnetic attraction force to transmit rotation, and when unnecessary, the two members can be separated or slid, making it possible to prevent rotation transmission. This eliminates the need to adjust the gap between the clutch rotor and armature by adjusting shims, which was required during assembly, making assembly extremely easy, and greatly reducing the assembly time for the entire device. effective.

[Brief explanation of drawings]

FIG. 1 is a schematic side sectional view showing one embodiment of the electric power steering device according to the present invention, FIG. 2 is an enlarged view of the main part thereof, and FIGS. 3 and 4 are respectively different embodiments of the present invention. It is a figure which shows an example. 1...Electric power steering device, 2...Stub shaft (
input shaft), 3... Binion shaft (output shaft), 4...
・Tone Yomber, 5...Rack, 6.7...
Steering gear body, 10... Large gear (transmitted gear), lOa... Teeth, 11... Electric motor, lla... Motor, 12... Gear shaft (gear shaft) ), 12a... Small gear (transmission gear), 12b...
...screw hole for adjusting backlash, 13...gear mechanism for transmitting steering assist force, 30...electromagnetic clutch. 31... Field core, 32... Clutch housing (fixed side member), 33... Clutch rotor, 34... Armature, 35... Flange-shaped member, 36... Leaf spring, 37... Spline joint, 38... Guide bin, 50... Guide bin, 51... Coil spring.

Claims (1)

[Claims] An electric motor is connected to the steering output shaft system via a gear mechanism for transmitting steering assist force and transmits rotational driving force when steering is required, and an electric motor is provided interposed in the middle of the gear mechanism from the motor to the steering output shaft system. A stationary side member comprising an electromagnetic clutch that selectively connects and interrupts rotation transmission between the motor side and a gear shaft side member having a transmission gear to the output shaft side, and includes a field core of this electromagnetic clutch. is fixed to the motor body side, a clutch rotor magnetized by a field core is provided on the motor shaft side, and an armature that is selectively attracted to the clutch rotor is attached to a member on the gear shaft side in the axial direction. An electric power steering device characterized in that the electric power steering device is supported so as to be in contact with the rotor in a slidable state.