Rotary drive for a torque and / or position sensor

Abstract

The invention relates to a rotary drive (10) for a torque and / or position sensor (12) of a steering rod (14) for a steering gear of a motor vehicle, comprising a steering rod (14) arranged in a steering gear housing; a sensor shaft (18) arranged adjacently with respect to the steering rod (14), wherein a pinion (18a) attached on the sensor shaft (18) or formed integrally with the sensor shaft (18) engages with a toothing system (14a) of the steering rod (14), wherein the pinion (18a) is designed to convert an axial movement of the steering rod (14) into a rotational movement of the sensor shaft (18), and wherein the steering rod (14) has at least one rolling region for rotationally fixing the steering rod (14) to the sensor shaft (18).

Description

[0001] Description

[0002] title

[0003] Rotary drive for a torque and / or position sensor

[0004] The invention relates to a rotary drive for a torque and / or position sensor of a steering rod for a steering gear of a motor vehicle.

[0005] State of the art

[0006] Due to the use of steering systems for steer-by-wire vehicles, new functional requirements arise for the steering gear.

[0007] For example, the SRAapa steering type (steering gear with ball screw) no longer requires a steering pinion, which converts the manual torque into a translational force. This allows the steering rod to be secured against rotation and mounted in a different way.

[0008] Due to the gear tolerance, gear wear, and susceptibility to noise, a separate thrust piece was previously required. This presses the rack against the steering pinion via a spring. To minimize play during steering, the thrust piece play must be adjusted in a complex process. Due to the high gear forces and the resulting wear, a relatively large adjustment travel through the thrust piece is also necessary. Special damping elements are required to reduce noise. The contact points are implemented using sliding friction.

[0009] However, sliding friction is a functionally undesirable effect. In a conventional steering system with a mechanical connection to the steering wheel, this negatively impacts steering feel. In a steer-by-wire application, it also complicates control.

[0010] Furthermore, in electromechanical power steering systems, the rack position and manual torque are currently measured and calculated using sensors and software. The torque sensor is driven by rotation via the steering pinion. The steering pinion and the gearing on the steering rod are very robust in their current design. This is due to the fact that the components currently serve multiple functions, such as transmitting steering forces, rotationally securing the steering rod, and rotationally driving a torque sensor.

[0011] It is therefore an object of the invention to provide an improved drive for a torque and / or position sensor of a steering rod for a steering gear of a motor vehicle, which enables an improved rotational fixation of the steering rod and an improved rotational drive of the position sensor.

[0012] Disclosure of the invention

[0013] The object is achieved according to the invention by a rotary drive for a torque and / or position sensor of a steering rod for a steering gear of a motor vehicle having the features of patent claim 1.

[0014] The present invention provides a rotary drive for a torque and / or position sensor of a steering rod for a steering gear of a motor vehicle.

[0015] The rotary drive comprises a steering rod arranged in a steering gear housing.

[0016] Furthermore, the rotary drive comprises a drive shaft arranged adjacent to the handlebar

[0017] Sensor shaft, wherein a pinion mounted on the sensor shaft or formed integrally with the sensor shaft engages with a toothing of the handlebar, wherein the pinion is designed to convert an axial movement of the handlebar into a rotational movement of the sensor shaft, and wherein the handlebar has at least one rolling area for the rotational fixation of the handlebar to the sensor shaft.

[0018] One idea of ​​the present invention is to constructively combine or integrate the two functions of rotatably fixing the handlebar to the sensor shaft on at least one rolling area of ​​the handlebar and to rotatably drive the torque sensor and / or position sensor.

[0019] Advantageous embodiments and further developments emerge from the subclaims and from the description with reference to the figures.

[0020] According to a preferred development, it is provided that the steering rod has a first rolling region for the rotational fixation of the steering rod to the sensor shaft and a second rolling region offset from the first rolling region for the rotational fixation of the steering rod to the sensor shaft, wherein the second rolling region is arranged at a predetermined angle to the first rolling region.

[0021] The rotational fixation of the steering rod is thus achieved via two flat running surfaces on the steering rod and two rolling elements on the sensor shaft. The operating forces are transmitted to the sensor shaft via the rolling elements. The gearing for the sensor drive is free from the operating loads of the steering system. The gearing only has to overcome the friction from the sensor. This significantly reduces the mechanical demands and the required accuracy of the gearing.

[0022] According to a further preferred development, a plain bearing and a tapered roller supported by the plain bearing are further positioned on an outer circumference of the sensor shaft. The tapered roller rests against the second rolling area of ​​the steering shaft. A third support point can also be provided, for example, via a cylindrical contour on the back of the steering rod through a bearing bush.

[0023] The use of rolling elements creates rolling friction in the anti-rotation device. The play and friction remain virtually constant throughout its service life. This is important for control and good NVH behavior.

[0024] The anti-twist area of ​​the steering rod can be easily machined using a form cutter, for example. This is simpler and more precise.

[0025] According to a further preferred development, it is provided that the tapered roller is conical.

[0026] Due to the rotatable mounting of the tapered roller on the sensor shaft, the different circumferential speeds of the rolling elements with different diameters can be compensated.

[0027] According to a further preferred development, it is provided that a radial bearing bush is arranged at least in sections on a radial outer circumference of the handlebar for the rotational fixing and mounting of the handlebar.

[0028] The diameter of the cylindrical rolling element differs only slightly from the pitch diameter of the gearing. If necessary, an additional degree of rotational freedom can be created at this point, e.g., by using an additional plain bearing or a needle roller and cage assembly.

[0029] According to a further preferred development, the tapered roller is designed to compensate for different circumferential speeds of rolling elements of different diameters, with a first rolling element being formed by the tapered roller and a second rolling element being formed by a predetermined section of the sensor shaft. This is necessary to ensure smooth rolling. Without this additional rotational degree of freedom, sliding or jamming could occur.

[0030] According to a further preferred development, it is provided that a toothing for the rotary drive, in particular the toothing of the handlebar and the pinion mounted on the sensor shaft or formed integrally with the sensor shaft, are structurally decoupled from the rotary fixation of the handlebar, in particular have play.

[0031] This makes it possible to provide a load-free gearing as well as a gearing for a slip-free sensor drive.

[0032] According to a further preferred development, it is provided that means for the rotational fixation of the steering rod to the sensor shaft, in particular the tapered roller, are arranged in the same axis as the sensor shaft.

[0033] Thus, the rotary sensor drive, the anti-twist device and a play compensation are advantageously located on the same axis.

[0034] Furthermore, the existing steering pinion can be replaced with a simple pre-hardened turned part (roller). The gearing, hardening process, post-processing, and crack detection are eliminated. Furthermore, the separate pressure piece commonly used can be eliminated.

[0035] According to a further preferred development, it is provided that the tapered roller is axially preloaded by a spring, in particular a disc spring, and wherein the tapered roller is axially movable.

[0036] This ensures exact positioning of the tapered roller relative to the rolling element.

[0037] According to a further preferred development, the toothing of the handlebar is attached to the handlebar as an additional component, and the toothing of the handlebar is attached to the handlebar by gluing, hot-melt bonding, spraying, welding, locking, or screwing. The assembly of the toothing of the handlebar can thus be flexibly adapted to a specific requirement profile.

[0038] According to a further preferred development, the material of the toothing of the handlebar differs from the material of the handlebar, with the toothing of the handlebar being formed from plastic or sintered metal. The material of the toothing of the handlebar can thus be selected accordingly depending on the torque transmission requirements.

[0039] The described designs and further training courses can be combined as desired.

[0040] Further possible embodiments, further developments and implementations of the invention also include combinations of features of the invention described previously or below with regard to the exemplary embodiments that are not explicitly mentioned.

[0041] Short description of the drawings

[0042] The accompanying drawings are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention.

[0043] Other embodiments and many of the aforementioned advantages will become apparent upon review of the drawings. The elements illustrated in the drawings are not necessarily drawn to scale.

[0044] Shown are: Fig. 1 a schematic representation of a rotary drive for a torque and / or position sensor of a steering rod for a steering gear of a motor vehicle according to a preferred embodiment of the invention; and

[0045] Fig. 2 is a cross-sectional view of the rotary drive for the torque and / or position sensor of the steering rod for the steering gear of the motor vehicle according to the preferred embodiment of the invention.

[0046] In the figures of the drawings, the same reference symbols designate the same or functionally equivalent elements, parts or components, unless otherwise stated.

[0047] A toothing 14a shown in Fig. 1 for the rotary drive 10, in particular the toothing 14a of the handlebar 14 and the pinion 18a mounted on the sensor shaft 18 or formed integrally with the sensor shaft 18, are structurally decoupled from the rotary fixation of the handlebar 14 and in particular have play.

[0048] Means for rotationally fixing the steering rod 14 to the sensor shaft 18, in particular the tapered roller 26, are arranged on the same axis as the sensor shaft 18. The tapered roller 26 is axially preloaded by a spring, in particular a disc spring 30. The tapered roller 26 is designed to be axially movable.

[0049] The toothing 14a of the handlebar 14 is also attached to the handlebar 14 as an additional component. The toothing 14a of the handlebar 14 is preferably attached by gluing.

[0050] Alternatively, the toothing 14a of the handlebar 14 can be attached to the handlebar 14, for example, by hot-bonding, injection-molding, welding, locking, or screwing. A material of the toothing 14a of the handlebar 14 differs from a handlebar material, with the toothing 14a of the handlebar 14 being formed from plastic or sintered metal.

[0051] The toothing 14a can also be made directly on the handlebar without any additional component, e.g. by forming.

[0052] The rotary drive 10 shown in Fig. 2 for a torque and / or position sensor 12 of a steering rod 14 for a steering gear of a motor vehicle comprises a steering rod 14 arranged in a steering gear housing (not shown in Fig. 2).

[0053] Furthermore, the rotary drive 10 comprises a sensor shaft 18 arranged adjacent to the handlebar 14, wherein a pinion 18a applied to the sensor shaft 18 or formed integrally with the sensor shaft 18 engages with a toothing 14a of the handlebar 14, wherein the pinion 18a is designed to convert an axial movement of the handlebar 14 into a rotational movement of the sensor shaft 18, and wherein the handlebar 14 has at least one rolling area for the rotational fixation of the handlebar 14 on the sensor shaft 18.

[0054] The steering rod 14 further comprises a first rolling region 20 for rotationally fixing the steering rod 14 to the sensor shaft 18 and a second rolling region 22 arranged offset from the first rolling region 20 for rotationally fixing the steering rod 14 to the sensor shaft 18. The second rolling region 22 is arranged at a predetermined angle to the first rolling region 20.

[0055] A plain bearing 24 and a tapered roller 26 supported by the plain bearing 24 are positioned on an outer circumference of the sensor shaft 18. The tapered roller 26 bears against the first rolling area 20 of the steering shaft. The tapered roller 26 is also conical. A further support point can also be provided, for example, via a cylindrical contour on the back of the steering rod by means of a radial bearing bush 28.

[0056] The radial bearing bush 28 is arranged at least in sections on a radial outer circumference of the handlebar 14 for the rotational fixation of the handlebar 14.

[0057] Furthermore, the tapered roller 26 is designed to compensate for different circumferential speeds of rolling elements of different diameters, wherein a first rolling element is formed by the tapered roller 26 and a second rolling element is formed by a predetermined section of the sensor shaft 18.

Claims

Claims 1. A rotary drive (10) for a torque and / or position sensor (12) of a handlebar (14) for a steering gear of a motor vehicle, comprising a handlebar (14) arranged in a steering gear housing; a sensor shaft (18) arranged adjacent to the handlebar (14), wherein a pinion (18a) mounted on the sensor shaft (18) or formed integrally with the sensor shaft (18) engages with a toothing (14a) of the handlebar (14), wherein the pinion (18a) is designed to convert an axial movement of the handlebar (14) into a rotational movement of the sensor shaft (18), and wherein the handlebar (14) has at least one rolling region for the rotational fixation of the handlebar (14) to the sensor shaft (18).

2. Rotary drive according to claim 1, wherein the steering rod (14) has a first rolling region (20) for the rotational fixation of the steering rod (14) on the sensor shaft (18) and a second rolling region (22) offset from the first rolling region (20) for the rotational fixation of the steering rod (14) on the sensor shaft (18), wherein the second rolling region (22) is arranged at a predetermined angle to the first rolling region (20).

3. Rotary drive according to claim 2, wherein a plain bearing (24) and a tapered roller (26) mounted by the plain bearing (24) are positioned on an outer circumference of the sensor shaft (18), wherein the tapered roller (26) bears against the second rolling area (22) of the steering shaft.

4. Rotary drive according to claim 3, wherein the tapered roller (26) is conical.

5. Rotary drive according to one of the preceding claims, wherein a radial bearing bush (28) for rotative fixing and mounting of the handlebar (14) is arranged at least in sections on a radial outer circumference of the handlebar (14).

6. Rotary drive according to one of the preceding claims, wherein the tapered roller (26) is designed to compensate for different circumferential speeds of rolling elements of different diameters, wherein a first rolling element is formed by the tapered roller (26) and a second rolling element is formed by a predetermined section of the sensor shaft (18).

7. Rotary drive according to one of the preceding claims, wherein a toothing (14a) for the rotary drive (10), in particular the toothing (14a) of the handlebar (14) and the sensor shaft (18) applied pinions (18a) or formed integrally with the sensor shaft (18) are structurally decoupled from the rotational fixation of the handlebar (14), in particular have play.

8. Rotary drive according to one of the preceding claims, wherein means for the rotational fixation of the steering rod (14) to the sensor shaft (18), in particular the tapered roller (26), are arranged in the same axis as the sensor shaft (18).

9. Rotary drive according to one of the preceding claims, wherein the tapered roller (26) is axially preloaded by a spring, in particular a disc spring (30), and wherein the tapered roller (26) is axially movable.

10. Rotary drive according to one of the preceding claims, wherein the toothing (14a) of the handlebar (14) is fastened to the handlebar (14) as an additional component, and wherein the toothing (14a) of the handlebar (14) is fastened to the handlebar (14) by gluing, hot-bonding, spraying, welding, locking or screwing.

11. Rotary drive according to claim 10, wherein a material of the toothing (14a) of the handlebar (14) differs from a handlebar material, wherein the toothing (14a) of the handlebar (14) is formed from plastic or sintered metal.

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