阅读说明：本技术 转向辅助装置 (Steering assist device ) 是由 G·利森费尔德 于 2019-07-16 设计创作，主要内容包括：描述了一种用于机动车辆的转向辅助装置(10),它包括方向盘侧转向轴(12)和与后者联接的车轮侧转向轴(16),由此与备用驱动器(20)联接的齿轮(18)安装在车轮侧转向轴(16)上。此外,传感器元件(26)被集成于齿轮(18)中,并通过安装在所述方向盘侧转向轴(12)处的第一传感器配对元件(28)而与在空间中固定的第二传感器配对元件(30)协同作用。(A steering assistance device (10) for a motor vehicle is described, comprising a steering-wheel-side steering shaft (12) and a wheel-side steering shaft (16) coupled to the latter, whereby a gear wheel (18) coupled to a backup drive (20) is mounted on the wheel-side steering shaft (16). Furthermore, a sensor element (26) is integrated into the gear wheel (18) and interacts with a spatially fixed second sensor counter element (30) via a first sensor counter element (28) which is mounted on the steering-wheel-side steering shaft (12).)

1. Steering assistance device (10) for a motor vehicle with a steering-wheel-side steering shaft (12) and a wheel-side steering shaft (16) coupled thereto, whereby a gearwheel (18) coupled to a backup drive (20) is mounted on the wheel-side steering shaft (16), characterized in that a sensor element (26) is integrated in the gearwheel (18) and interacts with a spatially fixed second sensor counter element (30) by means of a first sensor counter element (28) mounted on the steering-wheel-side steering shaft (12).

2. The steering assist device (10) according to claim 1, characterized in that the gear (18) is a worm gear, and the backup drive (20) is coupled to the gear (18) by a worm (22) that meshes with the gear (18).

3. Steering assistance device (10) according to one of the preceding claims, characterized in that the sensor element (26) comprises at least one magnetic element (26a, 26 b).

4. Steering assistance device (10) according to claim 1, characterized in that the first sensor counter-element (28) comprises a variable reluctance or a magnetic flux conductor and/or the second sensor counter-element (30) comprises a magnetic flux sensor.

5. The steering assist device (10) according to claim 1, characterized in that the sensor element (26), the first sensor partner element (28) and/or the second sensor partner element (30) are part of an angular rotation sensor (31), the angular rotation sensor (31) being configured to detect a relative rotation of the steering wheel-side steering shaft (12) compared to the wheel-side steering shaft (16).

6. The steering assist device (10) according to claim 1, characterized in that the steering wheel-side steering shaft (12) and the wheel-side steering shaft (16) are coupled to each other by a torsion element (14).

7. Steering assistance device (10) according to claim 6, characterized in that the sensor element (26), the first sensor partner element (28) and/or the second sensor partner element (30) together with the torsion element (14) are part of a torque sensor (35), the torque sensor (35) being configured to detect a steering torque inserted into the steering wheel steering shaft (12).

8. Steering assistance device (10) according to claim 1, characterized in that the gear wheel (18) is at least partially made of plastic, preferably entirely made of plastic.

9. Steering assistance device (10) according to claim 1, characterized in that it further comprises a third sensor counter element (46), said third sensor counter element (46) being fixed in space and cooperating with said gear wheel (18).

10. The steering assist device (10) according to claim 9, characterized in that the third sensor paired member (46) is a part of an angular rotation sensor (47), the angular rotation sensor (47) being configured to detect a rotational position of the wheel-side steering shaft (16).

11. Steering assistance device (10) according to claim 9 or 10, characterized in that the third sensor counter element (46) comprises a magnetic flux sensor, in particular a hall sensor.

12. Steering assistance device according to claim 9 or 10, characterized in that the third sensor counter element (46) cooperates with the gearwheel (18) via a transmission (42), in particular an intermediate transmission.

13. Steering assistance device (10) according to claim 12, characterised in that said transmission means (42) comprise a first rotationally fixed transmission wheel (36), said first rotationally fixed transmission wheel (36) being connected to said toothed wheel (18), said first rotationally fixed transmission wheel (36) being coupled to a second transmission wheel (38), said second transmission wheel (38) comprising a rotation axis (40) fixed in space.

14. Steering assistance device (10) according to claim 13, characterized in that at least one magnetic element (44) is located at the second transmission wheel (38).

15. The steering assist device (10) according to claim 1, characterized in that at least one stopper (48) is provided at the gear (18), the relative rotation of the steering wheel-side steering shaft (12) with respect to the wheel-side steering shaft (16) being restricted by the stopper (48).

Technical Field

The invention relates to a steering assistance device for a motor vehicle with a steering-wheel-side steering shaft at the steering wheel and a wheel-side steering shaft coupled to the latter, wherein a gear wheel connected to a backup drive is mounted on the wheel-side steering shaft.

Background

Such a steering assistance device is known, for example, from DE 102015000928B 3. The auxiliary drive is used here for inserting an auxiliary torque into the wheel-side steering shaft. Therefore, the steering assistance device is also described in DE 102015000928B 3 as a device for inserting an assistance torque.

In general, when the known steering assist device is operated, the relative torsion of the steering wheel-side steering shaft with respect to the wheel-side steering shaft, the torsion of the wheel-side steering shaft with respect to the housing, and the steering torque inserted into the steering wheel-side steering shaft are detected by the sensors. The spare drive is then controlled or regulated depending on the corresponding sensor value.

In the solution according to DE 102015000928B 3, the sensors required for detecting the above-mentioned parameters are placed in a sensor housing which is mounted in the region of the wheel-side steering shaft and which has a certain installation space requirement.

Disclosure of Invention

The object of the present invention is therefore to provide a steering assistance device of the type mentioned initially which has a particularly compact construction. In addition, precise control of the spare drive is ensured.

This object is achieved by a steering assistance device of the type mentioned initially, in which the sensor element is integrated in the gear wheel and interacts with a second sensor counter element which is fixed in space by means of a first sensor counter element which is mounted on the steering wheel-side steering shaft. The integrated sensor element is here a sensor element which is firmly connected to the gear wheel and is essentially formed as a unit in a geometric sense with the gear wheel. In particular, the integrated sensor elements are not individual sensor elements disposed in the housing, but are separate but connected by gears. By integrating the sensor element, a particularly compact construction of the steering assistance device is ensured. This applies in particular to the direction of the central axis assigned to the steering-wheel-side steering shaft and/or to the wheel-side steering shaft. Therefore, the steering assist device is short in the axial direction. Since the positioning of the sensors of the steering assistance device each comprises an element connected to the steering-wheel-side steering shaft, an element connected to the wheel-side steering shaft, and an element fixed in space, the first-mentioned parameters can be detected simultaneously with high accuracy. On this basis, the spare drive can be operated accurately and reliably.

The sensor counterpart element fixed in space is, for example, disposed in a housing, against which the wheel-side steering shaft can be rotated. The spatially fixed sensor counterpart element is therefore also referred to as being fixed to the housing. The housing can be a sensor housing only, which is designed to enclose the sensor element and the assigned sensor counter-element and is inserted, for example, into a housing of the steering assistance device. The housing of the steering assist device may also be described as a transmission housing. The housing may also be described as a combined sensor and transmission housing. It then also encases the transmission components, such as gears.

The sensor element may be bonded to the gear or integrated in the gear by one-shot molding. For example, the sensor element is cast in the gear. Other suitable methods for integrating the sensor elements are also possible. The sensor element can be permanently fixed to the gear wheel, for example, by soldering or welding processes.

According to one embodiment, the gear may be a worm gear and the backup drive may be coupled to the gear by a worm engaged with the gear. The term worm is understood here to mean a component of a worm-worm gear. As a backup drive, a motor is preferably used. Such a back-up drive and a corresponding worm-worm gear are proven prior art. In particular, they have a minimum installation space and are reliable in operation.

According to an alternative design, the sensor element comprises at least one magnetic element. The magnetic element is for example a permanent magnet. The magnetic element may also be a magnetic track containing a number of permanent magnets. Along the track, there is a variable magnetization range or alternatively an unmagnetized region and a magnetized region. Preferably, the magnetic track is configured substantially as an annular or circular track extending at a substantially constant radius around the rotational axis of the gear. In particular, by means of such a magnetic element, accurate sensor values can be generated. Furthermore, the magnetic element and/or the magnetic track have a relatively compact structure.

In an alternative, a plurality of substantially annular tracks are provided, which extend parallel to each other. One of the tracks can be designed as a so-called thick track, while the other of the tracks is designed as a so-called fine track. In this case, the coarser range of the sensed values produced by the sensor elements is determined by the coarse track. By means of the assigned fine track, a more accurate sensing value is then determined within the coarse range. Thus, by means of several magnetic tracks extending parallel to each other, the accuracy of the sensor element can be improved. It is obvious that the principle described on the basis of a single coarse track and a single fine track can also be extended to more than two tracks. The accuracy of the sensor element is thereby further improved. After the integration of the tracks into the gear, the required installation space is substantially independent of the number of tracks provided.

Preferably, the first sensor pair element comprises a variable magnetoresistor or a magnetic flux conductor and/or the second sensor pair element comprises a magnetic flux sensor. The structure is particularly simple and compact.

In this context, the magnetic flux conductor guides the magnetic field into the region of the first sensor partner element. The magnetic field may start from a magnetic element that is located away from the sensor counter element. Depending on the orientation of the magnetic field provided through the magnetic flux conductor, the same effect can be achieved in the magnetic field prevailing in the region of the first sensor partner as in the case with the magnetoresistor. This applies in particular to the case where the magnetic field provided by the flux conductor is oriented compared to the magnetic field prevailing in this range.

The magnetic flux sensor is configured here to detect different magnetic fluxes originating from the sensor element. Preferably, the magnetic flux sensor is a hall sensor.

The variable reluctance of the first sensor partner element preferably varies in the circumferential direction with respect to the steering wheel-side steering shaft. The variable reluctance is preferably located at or on a bearing disk which is rotationally connected and fixed to the steering-wheel-side steering shaft. Therefore, the different magnetic resistances are juxtaposed compared to the sensor elements mounted on the gear, and are thus rotationally connected and fixed to the wheel-side steering shaft in accordance with the relative position of the steering-wheel-side steering shaft. Furthermore, the size of the magnetic resistance is dependent on the position of the first sensor partner element in space or in comparison with the housing.

The first sensor counter element may additionally also comprise a magnetic flux concentrator device. Thus, the magnetic flux originating from the sensor element can be concentrated, i.e. the magnetic flux density is locally increased. In particular, the magnetic flux is concentrated in the following manner: there is a high magnetic flux in the range of the second sensor pair element.

The sensor element, the first sensor partner element and/or the second sensor partner element may be part of an angular rotation sensor which is configured to detect a relative rotation of the steering wheel side steering shaft in comparison to the wheel side steering shaft. Such an angular rotation sensor has a compact structure and delivers an accurate sensing value with respect to the relative rotation during operation. Its function is as follows: in its initial position, a magnetic flux originates from the sensor element, which magnetic flux is changed by the reluctance of the first sensor partner element and is detected by the magnetic flux sensor of the second sensor partner element. If the sensor element is now twisted relative to the first sensor partner element, the magnetic flux, which is fixed in space and in the housing and is detected by the second sensor partner element, changes. In this way, relative rotation of the steering wheel-side steering shaft with respect to the wheel-side steering shaft can be detected. The angle rotation sensor can provide relatively accurate sensing value for relative rotation and has a simple and compact structure.

In one modification, the steering wheel-side steering shaft and the wheel-side steering shaft are coupled to each other by a torsion element. For example, in this context, torsion elements are torsion bars, diaphragms and bent rods. The coupling of the steering-wheel-side steering shaft and the wheel-side steering shaft by the torsion element is a proven prior art. It is simple, compact and reliable.

The sensor element, the first sensor partner element and/or the second sensor partner element may be part of a torque sensor which is configured to detect a steering torque inserted into the steering-wheel-side steering shaft in conjunction with the torsion element. As explained above, the sensor element, the first sensor counter-element and/or the second sensor counter-element are part of an angular rotation sensor which is configured to detect a relative rotation of the steering wheel side steering shaft with respect to the wheel side steering shaft. The effects and advantages result therefrom. Furthermore, the mechanical torsional properties of the torsion element, in particular its torsional stiffness, are assumed to be known. From this information, i.e. the combination of relative rotation and mechanical torsion properties, the applied torque can be derived based on the angle of rotation. The mentioned elements thus form a simple, compact and reliably functioning torque sensor.

The gear wheel is advantageously made at least partially, preferably entirely, of plastic. Such a gear can be produced particularly simply and inexpensively. This is particularly true if a large number of gears are to be manufactured. At least in the region of the sensor element, the gear wheel is made of plastic. Another advantage of such gears is that the plastic is generally transparent to the magnetic field. Thus, a failure of the sensor based on the magnetic principle can be eliminated. Furthermore, the integration of the sensor element is particularly simple for such a gear.

According to a preferred embodiment, the gear wheels are scattered on the wheel-side steering shaft. Therefore, the gear and the wheel-side steering shaft can be coupled to each other at a particularly low cost. The assembly with the gear and the wheel-side steering shaft is also more compact because it is not necessary to provide a separate connecting element.

The steering assistance device may comprise a third sensor partner which is fixed in space and cooperates with the gear. In this context, fixed in space may mean that the third sensor counterpart element is mounted at the sensor housing and/or the transmission housing.

The sensor element, the first sensor partner element and/or the second sensor element may be part of an angular rotation sensor configured to detect a rotational position of the wheel-side steering shaft. After the third sensor counterpart element is fixed in space or in the housing, the absolute rotational position of the wheel-side steering shaft can thus be detected. For such sensor information, the spare drive can be controlled particularly accurately.

Preferably, the third sensor counter element comprises a magnetic flux sensor, in particular a hall sensor. The advantages and effects of such a sensor result from the interpretation of the second sensor counter element and the magnetic flux sensor it contains.

According to one embodiment, the third sensor element is operated together with the gear wheel by means of a transmission, in particular an intermediate transmission. Such a transmission device adjusts the detection range of the third sensor element, more precisely of the third sensor element, to the range of motion of the gear. Thus, when the rotational position of the gear is detected with the sensor, a particularly high level of accuracy can be achieved by the transmission in a small space.

Depending on the embodiment of the transmission, the transmission element, which directly cooperates with the sensor element, moves faster or slower than the gear wheel. Thus, its detection accuracy and/or its detection range may be increased depending on the sensor principle employed.

Preferably, the transmission means comprise a first rotationally fixed transmission wheel connected to the gear wheel, the first rotationally fixed transmission wheel being coupled to a second transmission wheel comprising a rotation axis fixed in space. Preferably, both transmission wheels are gears. The gear wheel and the third sensor element are therefore coupled to one another in a particularly simple and reliable manner. Furthermore, the coupling meets high tolerance requirements.

The at least one magnetic element may be located at the second drive wheel. This magnetic element can cooperate with a third sensor element for detecting the rotational position of the gear. Such a sensor therefore exhibits a particularly compact structure.

A stopper may be further provided at the gear, by which relative rotation of the steering wheel-side steering shaft with respect to the wheel-side steering shaft is restricted. Two stoppers may also be provided to restrict relative rotation of the steering-wheel-side steering shaft with respect to the wheel-side steering shaft in both directions. With such a stopper, the components of the steering assist device are protected from the effects of excessive twisting of the steering wheel-side steering shaft as compared to the wheel-side steering shaft. Such excessive twisting can lead to accidents or other failure conditions.

This stop also helps to provide another coupling between the steering-wheel-side steering shaft and the wheel-side steering shaft even in the event that the torsion element is defective. Thus, an emergency operation of the steering assist device is provided.

Furthermore, a variant is intended to realize the sensor element fixed in space and the transmission wheel as a unit which can be inserted into the housing. Thus, a steering assist device having a simple and compact structure is obtained.

Drawings

The invention will be explained below on the basis of exemplary embodiments shown in the drawings. Shown in these drawings are:

figure 1 is a cross-sectional view of a steering assist device according to the present invention,

figure 2 a non-cut away view of the steering assist device of figure 1,

FIG. 3 detail III of the steering assistance device of FIG. 2, an

Fig. 4 shows another detailed part of the steering assist device of fig. 1 and 2.

Detailed Description

Fig. 1 shows a steering assistance device 10 of a motor vehicle, which is not described in detail.

The steering-wheel-side steering shaft 12 is coupled to the wheel-side steering shaft 16 via a torsion element 14, which torsion element 14 is embodied in the embodiment shown as a torsion bar.

Further, the steering assist device 10 includes a gear 18, and the gear 18 is mounted on the wheel-side steering shaft 16.

This is coupled to the back-up drive 20.

In the embodiment shown, the gear 18 is a worm gear and the back-up drive 20 is connected to the gear by a worm 22 engaging the gear 18.

The backup drive 20 is configured to insert additional torque into the wheel-side steering shaft 16. Further, in this context, this means that the torque inserted by the backup driver 20 overlaps with the torque inserted onto the steering wheel-side steering shaft 12. The additional torque is therefore also referred to as an auxiliary torque.

In the embodiment shown, the gear 18 is made entirely of plastic.

The steering assist device 10 also includes a housing 24 (see fig. 2) that encases at least a range of the gear 18. The housing 24 is here made of plastic, but may also be made of metal.

Furthermore, a sensor element 26, which contains at least a magnetic element, is integrated in the gear wheel 18. In fig. 1, only the two magnetic elements 26a, 26b shown schematically may be considered as examples.

For better clarity, the magnetic elements 26a, 26b are more of the spur gear 18 than is practical. Thus, the magnetic elements 26a and 26b and the sensor element are sufficient for the above definition, in that they are firmly connected with the gear wheel and thus essentially form one unit in a geometrical sense.

The sensor element 26 in this case interacts with a spatially fixed second sensor counter element 30 via a first sensor counter element 28 which is mounted on the steering-wheel-side steering shaft 12.

In the exemplary embodiments herein, the fixation in space can be understood as follows: the second sensor counterpart element 30 is mounted at the housing 24.

The sensor element 26, the first sensor partner element 28 and the second sensor partner element 30 are part of an angular rotation sensor 31, which angular rotation sensor 31 is configured to detect a relative rotation of the steering wheel side steering shaft 12 in comparison to the wheel side steering shaft 16. Thus, the relative rotation angle is detected.

For this purpose, the second sensor counter element 30 contains a magnetic flux sensor, which is shown as a hall sensor in the example shown. Which is capable of detecting the magnetic flux originating from the magnetic elements 26a, 26b of the sensor element 26.

The first sensor mating element 28 also shows a variable magnetoresistor (see also fig. 4).

The variable reluctance is indicated by dashed line 32 in fig. 3. In this context, a long segment of the line 32 represents a relatively high reluctance and a short segment represents a relatively low reluctance.

It can be seen that the magnetic resistance varies along one circumferential section of the first sensor partner 28, so that in this circumferential section it always increases in the direction of rotation of the first sensor partner 28 and decreases in the opposite direction of rotation.

Furthermore, the first sensor counter element 28 comprises a support disc 34, at which the variable reluctance is mounted.

The variable reluctance may be formed by layers of material of different thicknesses with the reluctance or by characteristics of the material of the sensor element 28. In the latter case, the material of the sensor element 28 exhibits a varying reluctance. Alternatively, it may be based on the principle of magnetic flux lines, which transfer the overlapping magnetic fields originating from the magnetic elements 26a, 26b to the second sensor partner 30.

The second sensor counterpart 30, more precisely its magnetic flux sensor, continuously detects a magnetic flux which is modified by the variable reluctance from the sensor element 26. Here, it allows relative torsion of the reference-steering-wheel-side steering shaft 12 compared to the wheel-side steering shaft 16.

Furthermore, if the torsional characteristics of the torsion element are known, in particular its torsional rigidity is known, the torque inserted into the steering-wheel-side steering shaft 12 with reference to the relative torsion from the steering-wheel-side steering shaft 12 compared to the wheel-side steering shaft 16 is also allowed. Thus, there is one torque sensor 35.

The first drive wheel 36 is also rotatably connected and fixed to the gear 18. For practical reasons it can be manufactured at low cost in one piece with the gear wheel 18.

It is coupled to a second transmission wheel 38, the axis of rotation 40 of which 38 is fixed with respect to the casing 24.

The first drive wheel 36 and the second drive wheel 38 form a transmission 42. Here, the drive wheels 36, 38 are both gears in the embodiment shown. Other embodiments, such as hypocycloidal transmissions, are possible depending on the required gear ratio.

Further, a magnetic element 44 is mounted on the second transmission wheel 38.

This cooperates with a third sensor counter element 46, which third sensor counter element 46 is located in the exemplary embodiment here at the housing 24, according to the above definition of being fixed in space.

Here, the third sensor partner member 46 is a part of an angular rotation sensor 47 configured to detect a rotational position of the wheel-side steering shaft 16.

For this purpose, the third sensor partner 46 contains a magnetic flux sensor, which is here a hall sensor. This detects the magnetic flux originating from the magnetic element 44.

The third sensor counterpart element 46 thus cooperates with the gear wheel 18 via the transmission 42.

The rotational position of the gear 18 in relation to the housing 24 can be detected at the same time as the magnetic flux sensor comprised by the third sensor counter element 46 detects the magnetic flux originating from the magnetic element 44. In the exemplary embodiment herein, the rotational position is based on the absolute rotational position of the gear 18.

A stopper 48 is also provided at the gear 18, by which relative rotation of the steering wheel-side steering shaft 12 with respect to the wheel-side steering shaft 16 is restricted. Here, it is also possible for the torsionally elastic element to be integrated as an alternative to the torsion element 14.