WO2001087688A1

WO2001087688A1 - Improved arrangement of the torque sensor or hydrovalve of a vehicle servo power steering with an actuator

Info

Publication number: WO2001087688A1
Application number: PCT/DE2001/001775
Authority: WO
Inventors: Gerd Reimann; Willi Nagel
Original assignee: Robert Bosch Gmbh
Priority date: 2000-05-13
Filing date: 2001-05-10
Publication date: 2001-11-22
Also published as: DE10023584A1

Abstract

The invention relates to a vehicle power steering, comprising a steering wheel (1) which acts indirectly through a steering column (3) upon a steering mechanism (5), an actuator (21) which acts independently from the steering wheel angle upon the steering mechanism (5) through the steering column (3), as well as a servo device (9) having a torque sensor (11) placed on the steering column (3) between the steering wheel (1), on the one hand, and the actuator (21) and the servo device (9), on the other hand. Consequently, the torque sensor (11) can measure directly the torque transmitted from the steering wheel (1) to the steering column (3) so that friction losses or play in the actuator (21) do not affect in any way the measurement of the torque and that the vehicle driver experiences directly a feeling of steering.

Description

Improved arrangement of the torque sensor and the hydraulic valve of a servo-assisted steering with actuator for motor vehicles

State of the art

The invention relates to a steering system for a motor vehicle, with a steering wheel acting indirectly on a steering column via a steering column, with an actuator, the actuator acting independently of the steering wheel angle on the steering gear, with a servo unit acting on the steering gear and with one interacting with the servo unit at the Steering column arranged

Torque sensor and hydraulic steering according to the preamble of the independent claim 7.

The actuator is used to change the steering angle of the wheels regardless of the steering wheel angle, thereby

Advantages in terms of driving dynamics, driving safety and driving comfort can be achieved. The servo unit or the hydraulic working cylinder have the task of reducing the steering wheel torque required for steering.

In the case of steering with a servo unit, this is done in that, depending on the torque which is introduced into the steering column via the steering wheel, a first electro-electric motor acting indirectly on the steering column, which is part of the ω IΌ Cπ o OI o cπ Cπ

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This object is achieved according to the invention by a steering system for a motor vehicle, with a steering wheel acting indirectly on a steering gear via a steering column, with an actuator, the actuator acting independently of the steering wheel angle on the steering gear, with a servo unit acting on the steering gear and with a servo unit interacting, arranged on the steering column torque sensor, the torque sensor being arranged in the direction of the torque flow from the steering wheel to the steering gear in front of the actuator and the servo unit.

Advantages of the invention

This steering has the advantage that the torque sensor directly measures the torque transmitted from the steering wheel to the steering column, and that the actuator does not dampen the torque measured by the torque sensor. Frictional losses or play in the actuator have no influence whatsoever on the measurement of the torque, so that there is a direct steering feeling for the driver of the motor vehicle. In addition, the torque to be applied by the driver on the steering wheel is reduced.

In a supplement to the invention, the torque sensor is arranged on the steering column, so that a direct measurement of the torque coupled into the steering wheel by the driver is ensured by the torque sensor.

In a variant of the invention, the servo unit has a first control unit and a first one acting on the steering column via a reduction gear

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Working cylinder and with a hydraulic valve, wherein the hydraulic valve is arranged in the direction of the torque flow from the steering wheel to the steering gear in front of the actuator, so that the hydraulic valve is controlled directly by the torque transmitted from the steering wheel to the steering column, and that the actuator that from the steering wheel to the hydraulic valve acting torque does not dampen. Frictional losses or play in the actuator do not influence the hydraulic valve, so that the driver of the motor vehicle has a direct steering feel. In addition, the torque to be applied by the driver on the steering wheel is reduced.

In a supplement to the invention, the hydraulic valve is arranged on the steering column, so that the hydraulic valve that is coupled into the steering wheel by the driver is acted upon directly.

In a variant of the invention it is provided that the hydraulic valve is a rotary slide valve with a torsion bar, so that this proven hydraulic valve can also be used for hydraulic steering systems according to the invention.

In further additions to the invention, it is provided that the actuator has a superposition gear, in particular a planetary gear, a second electric motor and a second control unit with at least one signal access, so that the steering angle of the wheels is independent in order to improve driving dynamics, driving safety and driving comfort can be changed by the steering wheel angle.

One embodiment of the invention provides an actuator acting indirectly on the steering gear via the steering column, so that the actuator space available in the vehicle can be arranged.

Further advantages and advantageous embodiments of the invention can be found in the following description, the drawing and the claims.

drawing

Embodiments of the object of the invention are shown in the drawing and described in more detail below. Show it:

Figure lein a first embodiment of an anor according to the invention

Figure 2 shows a second embodiment of an Ano invention

Description of the embodiments

In Figure 1, a first embodiment of a steering system according to the invention is shown schematically. A steering wheel 1 acts indirectly via a steering column 3 on a mechanical steering gear 5, the outputs 7 of which are connected to the wheels of the motor vehicle (not shown) and determine the steering angle of the wheels.

To increase driving comfort, a servo unit 9 is provided which interacts with a torque sensor 11. The servo unit 9 essentially consists of a first control unit 13, a first electric motor 15 and a reduction gear 17. The first control unit 13 can be an electronic control unit and, as indicated by the dashed line in FIG. 1, it has the torque sensor 11 co CO tv> ro Cπ O Cπ o Cπ

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CL hj vQ tr P- tr Φ co ^ 1 dd α Φ ddd Φ rt DJ: rt d -> vQ co P- d P ^J Φ Φ

Φ Ω PJ Φ: rt HHO Ω K Φ di PJ PJ d P- d Φ H Φ O rt " _^ h- ¹ P- dd tr d CO d P- rt φ rt hj d tr hj CO • r- ¹ ω σ ι t <! r + cQ O hj Φ φ d Φ Φ rt DJ CL 3 Φ hd PJ φ tr tr co? d Φ P- Φ φ hj ds: d P- hd CL CL 3 Φ C CL CL CL tr Φ PJ = PJ: d cQ H d P- CL Φ • ^ d φ d φ PJ rt hj t → rr PJ P- F- ¹ DJ Φ tr d CL tr Φ d HH P- φ P- d ω Φ rt PJ d Φ h co d PJ cQ Φ <ld CL Φ M Ω vQ d co d CO Hi -J co hh P- H CO O d P- rt d Φ tr d tr

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shown in Figure 1. Alternatively, the torque sensor 11 can remain in the immediate vicinity of the steering wheel 1, so that the measured torque is not influenced by universal joints 32 in the steering column 3.

In Figure 2, a second embodiment of a steering system according to the invention is shown schematically. The same components or assemblies are provided with the same reference symbols.

This embodiment is hydraulic steering. The mechanical steering gear 5 is designed as a hydraulic steering gear and has a hydraulic working cylinder, not shown in FIG. 2. The torque transmitted from the steering wheel 1 to the steering column 3 actuates a hydraulic valve 33 with a torsion bar. The hydraulic valve 33 controls the hydraulic working cylinder of the steering gear 5 via connecting lines 35.

The hydraulic valve 33 is arranged between the steering wheel 1 and the actuator 21 on the steering column 3 such that the torque transmitted from the steering wheel 1 to the steering column 3 is applied to it directly. This arrangement means that the hydraulic valve 33 converts the torque coupled into the steering wheel by the driver into the control of the hydraulic working cylinder in a particularly sensitive manner. This creates the desired direct steering feel for the driver of the motor vehicle.

In this exemplary embodiment, too, the hydraulic valve 33 and the actuator 21 can be combined to form an assembly which can optionally also be flange-mounted on the steering gear 5. Compared to the prior art, the arrangement according to the invention of the servo unit 9 or hydraulic valve 33 and actuator 21 on the steering column 3 is possible without additional construction effort, ie without additional costs. All of the features shown in the drawing, their description and the patent claims can be essential to the invention both individually and in any combination with one another.

Claims

Expectations

1. Steering for a motor vehicle, with a steering wheel (1) acting indirectly via a steering column (3) on a steering gear (5), with an actuator (21), the actuator (21) acting independently of the steering wheel angle on the steering gear (5), with a servo unit (9) acting on the steering gear (5) and with a torque sensor (11) arranged on the steering column (3) cooperating with the servo unit (9), characterized in that the torque sensor (11) in the direction of the torque flow from the steering wheel (1) to the steering gear (5) in front of the actuator (21) and the servo unit (9) is arranged.

2. Steering according to claim 1, characterized in that the torque sensor (11) on the steering column (3) is arranged.

3. Steering according to claim 1 or 2, characterized in that the servo unit (9) has a first control unit (13) and via a reduction gear (17) on the steering column (3) acting first electric motor (15), and that the first control unit controls the first electric motor (15) as a function of the output signal of the torque sensor (11).

4. Steering according to one of the preceding claims, characterized in that the actuator (21) and the servo unit (9) are combined to form an assembly.

5. Steering according to one of the preceding claims, characterized in that the steering gear (5) is a mechanical gear.

6. Steering according to one of the preceding claims, characterized in that the actuator (21) and / or the servo unit (9) are flanged to the steering gear (5).

7. Hydraulic steering for a motor vehicle, with a steering wheel (1) acting indirectly via a steering column (3) on a mechanical steering gear (5), with an actuator (21), the actuator (21) independent of the steering wheel angle on the steering gear (5) acts with a hydraulic working cylinder acting on the steering gear (5) and with a hydraulic valve (33), characterized in that the hydraulic valve (33) in the direction of the torque flow from the steering wheel (1) to the steering gear (5) in front of the actuator (21) is arranged.

8. Steering according to claim 7, characterized in that the hydraulic valve (33) is arranged on the steering column (3).

9. Steering according to claim 7 or 8, characterized in that the hydraulic valve (33) is a rotary slide valve with a torsion bar.

10. Steering according to one of the preceding claims, characterized in that the actuator (21) has a superposition gear (27), a second electric motor (25) and a second control unit (23) with at least has a signal access (19).

11. Steering according to claim 10, characterized in that the superposition gear (27) is designed as a planetary gear.

12. Steering according to one of the preceding claims, characterized in that the actuator (21) acts indirectly via the steering column (3) on the steering gear (5).