JPH07315235A - Method of operating power steering system and power steeringsystem - Google Patents

Abstract

PURPOSE: To maintain a steering transmission rate at a proper value by switching the transmission device range of an actuator superimposing manual and automatic steering motions to the transmission direction for generating the initial steering required angle formed under the existence of a servo motion when the servo motion fails. CONSTITUTION: The input shaft 15 of a planetary gear dynamo-electric device 10 is engaged with the steering wheel of an automobile, a planetary gear 19 is revolved around a sun gear 18 on the input shaft 15, and an output shaft 16 is rotated by the revolution of the planetary gear 19 via a planetary carrier 16a. The ring gear of the planetary gear dynamo-electric device 10 is formed as a ring gear unit 11 constituted of a first ring gear 11a having inner tooth trains 20, 21 and a second ring gear portion having a spur gear 11b, and the spur gear 11b is driven by a servo motor via a tooth train. A slider 12 is provided between the input shaft 15 and the inner tooth trains 21, 22, and the mesh is controlled via a switching rod 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a power steering system, wherein a first steering motion corresponding to a driver's intention and a servo device are provided by an actuator formed as a transmission device. The present invention relates to a type in which the formed second steering movement is superposed and supplied to the steering transmission, and the transmission is switched when the servo movement fails.

Further, the present invention is a motor-operated power steering system, which is formed by a first steering motion corresponding to a driver's intention and a servo device via an actuator formed as a transmission device. Second
The steering movement of the servomotor is superposed and supplied to the steering transmission, and a switching means is provided for shutting off the superposition input side of the servo movement when the servo movement fails. .

[0003]

2. Description of the Related Art In such a type of power steering system, a transmission is provided to superimpose a steering wheel movement from a driver and an auxiliary rotary movement formed by a servo device. This transmission is designed, for example, as a planetary gear transmission and certainly reduces the steering wheel required angle and the steering wheel moment to be applied for normal operation, but is shockable in the event of an auxiliary movement failure. This causes a change in the steering transmission ratio.

Known motor-operated power steering systems (German Patent Application Publication No. 40313)
No. 16), the steering wheel output applied by the driver of the motor vehicle is superposed by means of an actuator by means of an auxiliary output of a servo output source, generally an electric motor, in which case the steering wheel to be applied by the driver. Wheel moment is reduced. At the same time, this allows the increased steering wheel required angle to be reduced to a normal degree by appropriate superposition of the auxiliary movements. At this time, the driver's intention to steer is detected by a steering angle signal or a steering angular velocity signal that indirectly or directly represents the movement of the steering wheel operated by the driver, and is supplied to the control device. This controller controls the corresponding electric motor. This electric motor supplies a rotary movement to one input side of an actuator designed as a transmission. The other input side of the actuator is connected to a steering wheel operated by the driver, and the output side of the actuator acts on the steering transmission. Such actuators, which provide a superposition of two rotary movements, are generally designed as mechanical differential systems, and many embodiments are realized, often in the form of planetary gear transmissions.

Such a planetary gear transmission, as well as a number of other mechanical devices which enable the additive superposition of the inputs and outputs, react in the event of a servo-auxiliary output failure only for safety reasons as follows: To do. Thus, in this case, the driver has to apply an increased steering wheel power, but this is not done by an increase in the steering wheel moment, but in the event of a fault, for example of an electric motor which outputs a servo assist output. When stopped, the steering wheel angle or steering wheel angular velocity must be increased by the driver himself, for example, to allow the same steering lock angle.

However, such characteristics of mechanical actuators are problematic, and it is not uncommon to violate given physiological conditions. This physiologic condition is clearly influenced by the behavior of the driver, which is formed over time when the vehicle is driven and then constantly repeated, in which case the driver must drive the vehicle in a defined curve radius. In this case, the driver automatically defines the specified steering wheel angle in the driver's own cerebral "calculation system", or selects routinely.

In the event of a servo output failure, the driver will immediately provide more force, for example, at a certain resistance that suddenly occurs in the steering wheel movement, which makes it customary for the driver. The turning angle diagram for the curve radius can be maintained, but the driver is not prepared to adjust a suddenly larger steering lock angle.

In such a case, the reaction of the driver of the motor vehicle becomes very slow, in this case almost the same for a particular curve which is sufficiently known to the driver and thus also stored in the driver's behavior. If the driver is suddenly required to apply a significantly large steering lock angle at the required moment, a very dangerous situation can result.

[0009]

SUMMARY OF THE INVENTION The object of the invention is to improve a method of the type mentioned at the outset in a power steering system in which an increased steering wheel required angle is produced by a fault in the servo output. (EN) It is possible to provide a method in which a steering transmission ratio set by a servo system free from failure, which is so-called blood and flesh of a driver, is reliably maintained even when a servo output fails.

A further object of the invention is to provide an advantageous power steering system for carrying out such a method.

[0011]

In order to solve this problem, in the method of the present invention, the transmission range of the actuator for superimposing the both steering movements at the time of the servo movement failure is
Switching to a more direct and direct transmission direction, which gives rise to the initial steering required angle that is formed approximately in the presence of servo movements, is tolerated by the increased steering wheel moment.

Further, in order to solve the above-mentioned problems, in the structure of the power steering system of the present invention, the switching means for shutting off the superimposed input side provided in the actuator at the same time when the servo motion fails, the transmission device component of the actuator at the same time. Also, the actuator transmission ratio between the transmission input shaft coupled to the steering wheel and the output shaft coupled to the steering transmission is
It is designed to be reduced in a direction that at least substantially maintains the initial required steering angle formed in the presence of servo movement.

[0013]

According to the present invention, the following advantages can be obtained. That is, the steering angle transmission ratio is wholly assisted by the switching of the transmission ratio in the actuator formed as a transmission, which adds and superimposes the steering movement introduced by the driver and the auxiliary steering movement output by the servo device. Since it remains almost unchanged even when a motion failure occurs, it is possible to reliably control a running situation having a large required steering angle when a servo output fails.

Actuators designed as such a transmission for superimposing rotational movements by addition usually have a planetary gear transmission. In this case, since the present invention switches the transmission of the planetary gear transmission to the direct transmission at the moment of the auxiliary movement failure, in some cases, only the steering wheel moment is automatically changed when the steering wheel required angle changes very little. Increases in response to transmission of the transmission. This is a characteristic that is considered comparable and acceptable to the failure of hydraulic or other force assisted power steering.

Another advantage of the present invention is recognized as follows.
In other words, if the function of the electric motor that produces the auxiliary movement is not well-ordered, the superimposing input side can be cut off, so that no undesired steering angle occurs in the steerable wheels.

It is also advantageous that the superimposed input side does not necessarily have to have a self-locking transmission stage (for example via a worm transmission corresponding to a planetary gear transmission). The reason for this is that the direct mechanical action from the steering wheel to the steerable wheels can always be realized by switching to the emergency travel position guaranteed by the present invention. Introducing an auxiliary movement via a worm gear into the area of a planetary gear transmission that superimposes a driving movement is described in DE-A 4
The arrangement described in the specification 031316 is necessary in order to prevent the electric motor from rotating in the reverse direction via the planetary gear transmission when the electric motor fails. This leads to a loss of steerability of the vehicle when the servo output fails.

Yet another advantage of the present invention is that, instead of such a self-locking transmission stage (worm transmission), which normally has an efficiency of less than 50%, an efficiency in the range of 95% is used. The use of a less expensive spur gear, which has a significantly lower power output and thus a smaller and lighter in construction, i.e. a cheaper electric motor, to enable the use of less expensive spur gear stages. It is also possible.

The present invention further has the following advantages. That is, when a high torque is abusively introduced into the steering wheel, an extremely high torque acts on the output side of the transmission based on the transmission ratio of the planetary gear transmission. This high torque requires the design of a steering transmission that is sufficiently oversized for standard performance. Even in such a situation, according to the present invention, since it is possible to switch to the emergency traveling position, the torque acting on the steering transmission can be remarkably reduced. The setting can be maintained.

Furthermore, the so-called "steer-by-wire" steering or automatic tracking is realized by another switching of the transmission improved according to the invention without a comparatively large additional construction effort. Is possible.

A further advantageous design of the invention also makes possible a particularly compact switchable steering transmission, in which case the switching mechanism itself is integrated in the planetary gear transmission. That is, the switching mechanism is incorporated into the hole provided in the sun gear and the adjacent hole provided in the correspondingly improved planetary carrier.

[0021]

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

Before describing the various embodiments of the invention, it should be emphasized once again that the invention aims at an improvement of the motor-operated power steering system according to DE 40 31 316 A1. . Therefore, the description of this known power steering system is also adopted in describing the present invention throughout. However, detailed description of various devices and systems described in the above-mentioned German Patent Application Publication will be omitted. In the arrangement described in DE 40 31 316 A1, a planetary gear transmission is used for the additive superposition of the steering movements. In this case, the central input shaft, which is connected to the sun gear of this planetary gear transmission, is loaded by the user of the vehicle by the rotation of the steering wheel at a steering angle formed by the user himself,
On the other hand, the ring gear (the planetary gear revolves around this ring gear) is driven by the electric motor forming the servo assist angle via the worm transmission, and the output shaft is coupled to the planetary carrier in a non-rotatable manner.

In the actuator thus formed, the ring gear is locked and the steering transmission ratio is automatically increased when the electric motor fails.

Therefore, in the embodiment described below,
When the auxiliary motor fails, the transmission ratio of the planetary gear transmission (for example, i = 2.5) is changed to the direct transmission ratio (for example, i = 1.
It is based on the basic idea of switching to 0). As a result, the steering wheel moment is increased correspondingly to the transmission ratio of the planetary gear transmission, but the initial steering wheel required angle is substantially maintained.

In the improved planetary gear transmission 10 according to the embodiment shown in FIG. 1, the input shaft 15 is connected to the steering wheel of a motor vehicle with a corresponding power steering system. The input shaft 15 is transferred to the sun gear 18. The planetary gear 19 revolves around the sun gear 18. This planetary gear 19
Is supported by the planetary carrier 16a. The planetary carrier 16 a is connected to the output shaft 16. The output shaft 16 is connected to its own steering transmission (not shown).

The ring gear of the planetary gear transmission 10 is constructed as a ring gear unit 11 having two parts. The ring gear unit 11 has a unique ring gear 11a as the first ring gear portion, and the diameter of the ring gear 11a has a stepped shape. The ring gear 11a has internal tooth rows 20, 2 respectively.
1 is provided. The ring gear unit 11 has a second
The spur gear 11b having the internal gear train 22 and the external gear train 23 is provided as the ring gear portion of the. The spur gear 11b of the ring gear unit 11 is appropriately driven by a servo electric motor (not shown) via a tooth row arranged on the outer diameter, and thus constitutes a superposition input side. This servo electric motor is disclosed in German Patent Application Publication No. 4031.
It can be controlled as defined by the control circuit illustrated in FIG.

Further, the slider 12 is provided between the input shaft 15 of the sun gear 18 and the internal tooth rows 21 and 22 of the ring gear unit. The slider 12 is preferably embodied as a ring cylinder and partially has an internal tooth row and an external tooth row. Both tooth rows can mesh with the same partial inner tooth row and outer tooth row provided on the ring gear unit 11 and the input shaft 15 depending on the axial position of the slider 12.

The slider 12 has an external tooth row 24.
The outer tooth row 24 can straddle both inner tooth rows 21 and 22 provided on the ring gear 11a and the spur gear 11b.
This corresponds to the slider axial position shown in FIG. In this case, the partial internal tooth row 25 of the slider 12 is disengaged from the first partial external tooth row 26 provided on the input shaft 15. The same applies to slider 1
The same applies to another partial internal tooth row 25 ', which is axially offset in 2 (described in detail below). This internal tooth row 25 'is another partial internal tooth row 26' provided on the input shaft 15 at the slider axial position shown in FIG.
Is not in mesh with. The additional coupling ring 14 is not described in detail here either. This coupling ring 14 is shown with a casing area 17 (only partly shown) with an internal toothing for the purpose of facilitating the understanding of the invention for the moment only, and will be explained in more detail later on in the section "Steering. Only important for "by-wire" slider position. This "Steer by
The "wire" slider position will be described in detail with reference to FIG.

Referring to FIG. 1, the slider 12 is via an optional switching rod 27 having a spherical end portion 27a rotatably engaged in an annular groove 12a provided in the slider 12. It turns out that it can be moved in the axial direction. This gives rise to another basic function of the planetary gear transmission 10 which is illustrated in all three drawings.

Thus, as shown in FIG. 1, the slider 1
Since the outer tooth row 24 of No. 2 connects both constituent parts of the ring gear unit 11 to each other, the rotary movement is introduced through the outer tooth row 23 of the spur gear 11b of the ring gear unit 11 to assist the movement of the electric motor. Also, the steering wheel angle applied by the user is also received and transmitted to the output shaft 16 for the purpose of superposition. Therefore, in the state shown in FIG. 1, the planetary gear transmission 10 is in the steering assist position, that is, in the standard operating position of the power steering. In this standard operating position,
The ring gear 11a and the spur gear 11b are connected to each other in a form-fitting manner, in which case the slider 12 rotates together with the ring gear unit 11.

The emergency traveling position shown in FIG. 2 (in FIG. 1, FIG. 2 and FIG. 3, the same components are provided with the same reference numerals) must be switched when the electric motor fails or malfunctions. It is created when it must be.
Failure or malfunction of the electric motor can be detected by any type of sensor. As a result, the slider 12 is disengaged from the internal gear train 22 of the spur gear 11b by the external gear train 24 during the axial movement toward the left side in the planes of FIGS. It does not affect the transmission function. In this case, slider 1
2, the partial internal tooth row 25 of the slider 12 aligns with and meshes with the external tooth row 26 of the input shaft 15, so that 1: 1 entrainment of the ring gear unit 11 occurs. This results in a transmission ratio i = 1.0 between the steering wheel and the output shaft 16 of the transmission. That is, the superposition input side is disconnected.

Furthermore, the embodiment shown in FIGS. 1 and 2 requires only a slight improvement in terms of cost,
It is also suitable for implementing an additional function, the "steer-by-wire" function already mentioned above. This "steer-by-wire" function results in the axial slider position as shown in FIG.

In this switching position, the coupling ring 14 described further above is used. The coupling ring 14 engages with its internal tooth row 25 ', a partial external tooth row 26' of the input shaft 15 in the slider position which is completely extended to the right side, and positions the input shaft 15 with its external tooth row 14a. The inner casing 17a of the stationary casing 17 is fixed in position. The input shaft 15 is in this case a locked sun gear 18
In accordance with the form-locking connection between the slider 12 and the spur gear 11b with the ring gear 11a, which is held stationary in the, and is driven by the servomotor, only the steering movement introduced exclusively via the superposition input side. It becomes impossible to communicate. Therefore, in this switching position, steering is performed only by the electric motor. But, of course, this kind of "steer-by-wire"
Coupling ring 1 if no function is required
4 and the internal tooth row 17a of the casing 17 can be omitted.

Alternatively, the switching mechanism whose functional principle has been described with reference to FIGS. 1 and 2 may alternatively be constructed, for example, in the form of a tension wedge transmission device as shown at 10 'in FIGS. Is also possible. In this case, "Stair-by-
The "wire" function is not incorporated.

Due to the improved construction of the slider 12 ', as shown in FIGS. 4 and 5, in the steering assisted position shown in FIG. 4, the entraining element, preferably the lock ball 28, engages the spur gear 11b'. Ring gear 11a '
It becomes to be pushed to the entrainment position of the shape connection between and. The lock ball 28 is fitted into the axial extension 30 of the spur gear 11b ', and is pulled back to the right side in the plan view of FIG. 4 by the outer edge 32 of the slider 12' which is covered on the outer side in the radial direction. At the position of the slider 12 ′, the slider 12 ′ is pressed by the entrainment groove 31 provided in the ring gear 11 a ′ and extending in the axial direction.

On the other hand, as shown in FIG. 5, when the slider 12 'is moved to the abutting position on the left side to take the emergency traveling position, the input shaft 1 becomes clear as shown in FIG.
Another lock ball 28 'is pushed outward from the axial groove 33 forming a lock ball rolling path, which is provided on the ring gear 5'and rises outward in the radial direction. 11a 'is inserted into the axial entrainment groove 34 inside the ring gear 11a' for the purpose of directly carrying the shape-connecting shape. Therefore, in the emergency traveling position shown in FIG. 5, the superimposing input by the spur gear 11b 'is blocked, and in this case as well, the input shaft 15' and the ring gear 11 'are blocked.
A form-locking connection with a'is produced, which form-connecting the output shaft 16 directly.

Further, in another embodiment of the present invention shown in FIGS. 6 and 7, the switching mechanism can be incorporated inside the planetary gear transmission. This results in a particularly compact structure, which also enables the steering wheel assistance position and the emergency travel position as transmission positions.

In this embodiment, the steering wheel is connected to the input shaft 15 ″, and the steering gear (not shown) is connected to the planetary carrier 16a ′ via the output shaft 16. The ring gear 11 ″ of the planetary gear transmission 10 ″ shown in FIGS. 6 and 7 has a spur gear tooth row 35 located outside in an arbitrary stepped range of its outer diameter. Through this spur gear toothing 35, an auxiliary electric motor (not shown) can introduce its servo assistance, as in the previously described embodiment. That is, also in this case, the spur gear tooth row on the outer side of the ring gear forms the superimposed input side.

The input shaft 15 '' has a hole 36, which is stepped as a hole 36 'and leads to the planetary carrier 16a'. A switching slider 37 is supported in both holes 36, 36 ', and the switching slider 3 is
7 can be slid axially via a switching rod 37a guided outwards to both switching positions defined by a stopper.

In this case, the input shaft 15 ″ connected to the steering wheel and the sun gear 18 ′ are constructed so as to be rotatable relative to each other, and in this case also, a switching ball is provided. Depending on the position of the changeover slider 37, this changeover ball is moved by this changeover slider 37 so that the input shaft 15 ″ is connected to the sun gear 18 ′ in a form-fitting manner or to the planetary carrier 16 ′. Bind to.

For this purpose, the tubular region of the input shaft has a plurality of radial holes 38 distributed over its entire circumference, which holes 38 accommodate a first switching ball 39.

Since the input shaft 15 '' is a tubular portion thereof and projects into a hole arranged in the planetary carrier 16a ', another radial hole 3 is formed in this input shaft tube piece.
8'is provided, which hole 38 'accommodates a corresponding switching ball 39'. In this case, sun gear 1
In the hole for accommodating the input shaft 15 'provided in 8', the first
An axial semi-circular first groove 40 for accommodating the switching ball 39 of FIG. 1 is machined and at the same time an adjacent hole provided in the planetary carrier 16a 'for accommodating the input shaft tube piece is formed. , Axial semicircular second groove 40 '
Is processed and molded. Both switching balls are switching slider 3
7, the radial ridge 41 presses the groove outward in the radial direction, so that the input shaft 1
A form-locking connection between the 5 ″ and the sun gear 18 ′ is formed or a form-locking connection between the input shaft 15 ″ and the planetary carrier 16a ′ is directly formed. This results in both switching positions, a "steering aid" position and an "emergency travel" position.

Therefore, also in this case, the input shaft 15 ''
A selective form-fitting connection is obtained between the sun gear 18 'and the sun gear 18' or between the input shaft 15 '' and the planetary carrier 16a ', so that in the event of a failure of the steering assistance movement the steering movement is certainly for the user. It is relatively immobile, but it does not appear to have changed at all, contrary to the will of the user.

The switching operation via the corresponding switching rod can be operated without problems by means of suitable signals. This signal detects a failure of the electric motor providing the auxiliary movement and is, for example, electromagnetically converted to carry out the switching movement.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing the basic principle of a planetary gear transmission.

FIG. 2 is a cross-sectional view showing the planetary gear transmission shown in FIG. 1 in an emergency traveling position.

FIG. 3 shows the planetary gear transmission shown in FIG.
FIG. 6 is a cross-sectional view shown in a third position to enable “by wire” operation.

FIG. 4 is a cross-sectional view showing a modified embodiment of the planetary gear transmission in which the switching to the steering assisted position is realized in the form of a tension wedge transmission.

FIG. 5 is a cross-sectional view showing a modified embodiment of the planetary gear transmission in which switching to an emergency travel position is realized in the form of a tension wedge transmission.

FIG. 6 is a cross-sectional view showing another embodiment of a transmission device for switchable steering transmission according to the tension wedge principle.

7 is a cross-sectional view taken along the line VII-VII of FIG.

[Explanation of symbols]

10, 10 ″ planetary gear transmission, 10 ′ tension wedge body transmission, 11, 11 ″ ring gear unit,
11a, 11a 'ring gear, 11b, 11b'
Spur gear, 12, 12 'slider, 12a annular groove, 14 coupling ring, 14a external tooth row,
15, 15 ', 15 "input shaft, 16, 16a'
Output shaft, 17 casing range, 17a casing tooth row, 18, 18 'sun gear, 19 planetary gear, 20, 21, 22 inner tooth row, 23, 24 outer tooth row, 25, 25', 26, 26 'inner tooth row, 27
Switching rod, 27a end portion, 28, 28 'lock ball, 29 radial notch, 30 extension,
31 entrainment groove, 32 outer edge portion, 33 axial groove,
34 entrainment groove, 35 spur gear tooth row, 36 hole, 3
6'hole, 37 switching slider, 37a switching rod, 38,38 'hole, 39,39' switching ball, 40,40 'groove, 41 raised portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Matthias Huckle Feijingen Rosenberg, Germany 15 (72) Inventor Wolfgang Kramer Germany Stuttgart Wilkenwaldstraße 133 (72) Inventor Reiner Muenz Germany Dezingen Gel Ringer Wake 4

Claims (9)

[Claims] 1. A method of operating a power steering system, comprising: a first steering movement corresponding to a driver's will, via a actuator formed as a transmission, and a second steering movement formed by a servo device. Supplying to the steering transmission by superimposing the steering movement, and in the type of switching the transmission when the servo movement fails, the transmission range of the actuator that superposes both steering movements when the servo movement fails, Power steering, characterized in that it switches to a more direct direct transmission direction that gives rise to the first steering required angle that is formed almost in the presence of servo movements, in which case it accepts increased steering wheel moments How to drive the system. 2. An actuator formed as a transmission is equipped with a planetary gear transmission, and superimposed input is performed via a ring gear of the planetary gear transmission, and a servo movement provided in the ring gear when the servo movement fails. The coupling input side used by is disconnected and the ring gear and the sun gear are directly coupled to the input shaft, or the ring gear is completely decoupled so that the input shaft becomes a planetary carrier coupled to the output shaft. The method according to claim 1, wherein the connection is made by direct form connection. 3. A "steer-by-wire" operation is performed by additional switching in the transmission range of an actuator that superimposes the two steering movements, and when the "steer-by-wire" operation is performed, Input for disengaging the working connection between the first steering movement corresponding to the will and the second steering movement supplied to the steering transmission and supplying the first steering movement to an actuator formed as a transmission. 2. The method as claimed in claim 1, wherein the locking of the shaft interrupts the first steering movement and the servo movement is operatively coupled with the steering transmission, and thus the steering operation is carried out only via the servo movement. 4. A motor-operated power steering system, wherein a first steering movement corresponding to a driver's intention is provided via an actuator (10, 10 ', 10'') formed as a transmission device. And a second steering motion formed by the servo device, which is superimposed and supplied to the steering transmission device, and moreover, switching means for shutting off the superimposed input side of the servo motion when the servo motion fails. In the type in which (12, 12 ', 37) is provided, the switching means for shutting off the superimposed input side provided at the actuator (10, 10', 10 '') at the same time when the servo movement fails Also affecting the transmission components of the actuator, the transmission input shaft (15, 15 ', coupled to the steering wheel,
15 '') and the actuator transmission ratio between the output shaft (16) coupled to the steering transmission are reduced in a direction that at least substantially maintains the initial steering required angle formed in the presence of servo movement. The motor-operated power steering system is characterized by: 5. An actuator for producing a superposition of a steering wheel movement and an auxiliary movement is formed as a planetary gear transmission (10, 10 ', 10''), the superposition input coupled to a servomotor being a planetary gear. Ring gears (11, 1) of gear transmissions (10, 10 ', 10'')
1 ', 11''), the switching means shuts off the ring gear range having the superimposed input side when the servo movement fails, and the input shaft (15, 1'').
5 ', 15'') is adapted to be connected in a form-locking manner to a ring gear or directly to a planetary carrier (16a') connected to an output shaft (16). Motor operated power steering system. 6. A ring gear unit of a planetary gear transmission (10) is formed as a ring gear unit (11) consisting of two parts, both parts of which mesh with a planetary gear (19) in an internal gear train. (11a)
And a second for receiving the superimposed input via the external tooth row (23)
And a ring gear portion (11b) of the ring gear unit (11a, 11b), wherein both ring gear portions (11a, 11b) are provided by using a slider (12) arranged between the ring gear unit (11) and the input shaft (15). The slider (12) can be mechanically coupled to each other via an external tooth row and an internal tooth row (21, 22, 24, 25, 26) which partially mesh with each other in accordance with the axial position of the slider (12). 12) is the first
In the position (2), the ring gear parts (11a, 11b) are connected to each other, and the superimposed input acts on the ring gear unit (11), while in the second slider position, the spur gear (11b) is formed. The second ring gear portion thus cut off is rotatably blocked, and the input shaft (15) is directly and formally connected to the remaining first ring gear portion (11a) meshing with the planetary gear (19). And planetary gear transmission (10)
Input shaft (15) connected to the steering wheel
With a standard connection between the sun gear (18) and the input shaft (15) maintained during the direct connection of the rotational movement of the steering wheel, the steering required angle is almost the same as in the case where the steering wheel is actuated by the servo movement. Motor-operated power steering system according to claim 4 or 5, characterized in that the transmission ratio of the entire planetary gear transmission (10) is formed such that 7. The slider (12) is axially slidable into an additional switching position that enables "steer-by-wire" operation, in which switching position the slider (1)
2) is connected to the casing tooth row (17a) by the input shaft (1
5) By moving the coupling (14) that locks the rotational movement of the steering wheel and the rotational movement of the steering wheel, the steering operation can be performed only through the superposition input side at the switching position, and the effect of the servo operation is exclusively exerted. 7. The motor-operated power steering system according to claim 6, wherein the form-locking connection of the two ring gear parts (11a, 11b) is ensured for the purpose of enabling the steering operation only when receiving the steering force. 8. A slider (12 ') arranged between the input shaft (15') and both ring gear parts (11a ', 11b') has a through hole or a longitudinal entrainment groove (31).
By selectively pushing the coupling ball (28) inward in the radial direction, both ring gear parts (11a ', 11b') are alternatively in the steering assisted position.
Of the second ring gear portion (11b ') connected to the shape-connecting rotary coupling or the superimposing input side, the input shaft (15'), and the blocked first ring gear portion meshing with the planetary gear ( Motor-operated power steering system according to claim 4 or 5, characterized in that it forms a form-locking connection with the locking ball (28 ') with respect to 11a'). 9. A planetary carrier (16) selectively connected between the input shaft (15 ″) and the sun gear (18 ′) or between the input shaft (15 ″) and the output shaft (16).
A switching slider (37), which causes a coupling connection with a ') via a switching ball (39, 39'), is provided in a hole (36) provided in the input shaft, and thus a planetary gear transmission (37). 10 ″) incorporated into the interior of the switching ball (39, 39 ′) by the respective radial positions of the switching ball (39, 39 ′) depending on the corresponding axial sliding position of the switching slider (37). Motor as defined in claim 4 or 5, characterized in that the switching slider (37) is adapted to move the switching ball to each entrainment position by means of a radially enlarged ridge (41). Actuated power steering system.