Steering system with a steering housing and a side housing cover, and motor vehicle with such a steering system

Abstract

The invention relates to a steering system (16) with steering housing (20) and side housing cover (22) as well as with a steering rod (18) penetrating the steering housing (20) and the housing cover (22), wherein a sleeve (24) for external protection of the steering rod (18) is attached directly or indirectly to the housing cover (22). The invention is based on the objective of providing a steering system (16) with steering housing (20) and a motor vehicle (10) with such a steering system, with which a defective boot, through which fluids could penetrate into the steering housing, is detected as quickly and reliably as possible. This task is solved by providing at least one fluid guidance structure on the inside of the housing cover (22) such that fluids penetrating the housing cover (22) on the cuff side are forcibly guided from the cuff side to a designated drainage area (52).

Description

[0001] The invention relates to a steering system comprising a steering housing, a steering rod at least partially arranged within a housing body, and a side housing cover through which the steering rod penetrates. The invention further relates to a motor vehicle with such a steering system. In particular, the invention relates to a steering system with a steering rod that is functionally coupled to a drive for a steering device or steering assist device, especially a drive motor, which provides additional force and / or torque as needed to reduce the steering torque required by the driver or even to completely take over the steering. Particularly in the latter configuration, the steering system can also be designed as a steer-by-wire system.

[0002] Steering systems with steering housings are known in practice, where the steering rod penetrates the housing on both sides. In some such steering systems, the steering rod also has a spindle section driven by a ball screw. The ball screw drive of such steering systems is typically driven by at least one axially parallel electric motor, which is functionally connected to the ball screw nut via a traction drive. A belt drive is particularly common as the traction drive.

[0003] From DE 10 2008 041 303 A1, a power steering system with a servo motor on a steering housing is known. The servo motor is operatively connected via a traction element drive within the steering housing to an axially displaceable component, forming a helical motion. In this component, at least one disc or wheel and a traction element of the traction element drive are protected from fluid ingress into the steering housing by means of a component that at least partially encloses them. This component is an additional protective housing for the traction element drive, which entails additional manufacturing and assembly costs as well as additional weight. Maintenance is also made more complex. The design of a side cover for the steering housing is not described in detail in the publication.

[0004] German patent DE 10 2017 207 094 A1 discloses a steering system control device for providing steering force and / or steering torque on demand by means of a drive unit controlled by a control unit. The control unit is enclosed in a control housing. A cable entry point is provided, leading to a sensing chamber adjacent to the control housing. Laterally adjoining sleeves, referred to as bellows, are mentioned. However, the design of a side housing cover of a steering housing with an adjoining bellows is not described in detail in the document.

[0005] US patent 2020 / 0088553 A1 describes a steering gear housing structure with a specially designed seal. The design of a side cover for the steering gear housing is not discussed in detail in the document.

[0006] Steering housings with a side cover, through which a steering rod penetrates, are known from the steering systems described above and from practical experience, as well as from DE 10 2017 207 094 A1. A sleeve is typically attached to each housing cover, which encloses the steering rod on the outside and protects it from external influences such as water, dirt, etc. Problems arise when the sleeve becomes leaky due to age or other forces or media, especially in the case of a steer-by-wire steering system, or when the unnoticed ingress of moisture or dirt could lead to a condition that could pose an immediate danger to personal safety.

[0007] The invention is based on the objective of providing a steering system with a steering housing and a motor vehicle with such a steering system, with which a defective boot, through which fluids could penetrate into the steering housing, is detected as quickly and reliably as possible.

[0008] The problem is solved according to the invention by the features of the independent claims. Further practical embodiments and advantages of the invention are described in connection with the dependent claims.

[0009] A steering system according to the invention comprises a steering housing and a side housing cover. Furthermore, a steering rod penetrating the steering housing and the housing cover is provided, wherein a sleeve for external protection of the steering rod is attached directly or indirectly to the housing cover. In addition, at least one fluid guidance structure is formed on the inside of the housing cover such that fluids penetrating the housing cover on the sleeve side are forcibly guided from the sleeve side to a designated drainage area. In other words, the housing cover is designed such that a fluid drainage path is formed in the housing cover such that fluids are guided to the designated drainage area by means of the fluid guidance structure.This means that regular inspection of the designated drainage area allows for reliable detection of any steering system boot damage that could allow fluids to leak through the boot and housing cover into the steering housing and thus into the steering system. In the simplest case, this inspection can be carried out by someone interested in checking the safety of their vehicle (possibly their own) before each journey. Alternatively, the inspection can be routinely performed by qualified personnel during workshop visits, service appointments, and other work on the vehicle.It is preferred if the check can be carried out automatically by the vehicle itself, especially at each vehicle start, in order to inform the driver immediately before starting the journey about a potentially critical fluid ingress into the steering system or even to shut down the vehicle itself and thus not expose the safety of users to any risk.

[0010] In a practical embodiment of a steering system according to the invention, at least one inwardly projecting rib is formed as a fluid guide structure.

[0011] Alternatively or in addition, in another practical embodiment at least one trough-like structure is designed as a fluid guidance structure.

[0012] Both inward-projecting ribs and channel-like structures, which in particular refer to a recess extending outwards, can be formed relatively easily and cost-effectively in a housing cover. For this purpose, an already manufactured housing cover can be subsequently mechanically, chemically, or otherwise processed, and / or the housing cover can be equipped with additional elements to form a rib in the form of a wall-like structure. This structure serves to guide any liquid, especially water, entering the housing cover in a specific direction towards a designated drainage area. A designated drainage area does not necessarily mean an area through which the liquids are directly channeled out of the housing cover to the outside.This can also be an additional recess formed in the housing cover itself or in an adjacent element, into which any liquid that has penetrated drains away in the sense that it is caught and collected in the intended drainage area.

[0013] Fluid guidance structures can be formed particularly easily and cost-effectively in the housing cover if, according to another practical embodiment, they are integrally formed on the housing cover and thus part of its geometric shape. In this case, especially if the housing cover is manufactured by casting, the mold simply needs to be designed such that the at least one rib or ribs and / or the at least one channel or channels are formed during the casting process itself. If the rib(s) and / or channel(s) are formed without additional material, there are no additional material costs, and the housing cover does not have a higher component weight compared to a housing cover without these fluid guidance structures.In the case of a new design for a housing cover, the invention can be implemented without additional costs and without weight disadvantages compared to known housing covers. One or more grooves can even be formed, potentially reducing the component weight, if the wall thickness of the housing cover in the areas where the groove(s) are to be formed allows for material reduction.

[0014] In practice, the housing covers of steering systems often have a relatively small dimension in the transverse direction (y-direction) of the vehicle. Particularly in such cases, it is further preferred if the fluid guidance structure leads to a further fluid guidance structure formed in another housing part of the steering housing. In this case, any penetrating fluid, especially water, is at least partially guided through the housing cover in such a way that it subsequently enters a subsequent path in another housing part and is again guided there to a designated drainage area by means of a fluid guidance structure. It should be noted in this context that "another housing part" refers in particular to the steering housing itself.The steering housing can be designed as a single piece or in multiple pieces, and the fluid guidance structure in the steering housing can extend partially or completely over one or more parts.

[0015] In a further practical embodiment of a steering system according to the invention, the fluid guidance structure leads directly or indirectly to a fluid collection structure and / or to a sensor. In this case, for example, a fluid collection structure, in particular in the form of a recess, can be formed in the housing cover itself, and / or a sensor, in particular a sensor designed for detecting fluid, can be arranged in the housing cover such that any fluid penetrating the housing cover is detected directly.

[0016] Alternatively, if the steering system has a fluid guide structure that leads to a further fluid guide structure formed in another housing part of the steering housing, the fluid guide structure can indirectly lead to a fluid collection structure and / or a sensor via the further fluid guide structure. The foregoing applies accordingly, although in the case of a further fluid guide structure, any fluids that have penetrated must first flow from the housing cover into the further housing part in order to be detected. Nevertheless, this embodiment can be advantageous, particularly if the arrangement of a sensor is more practical for reasons of installation space and / or technical reasons, for example, due to simplified power supply and / or simplified assembly and disassembly of the housing cover.

[0017] Particularly when dealing with a steering system that includes a drive element, for example, a steering system with a drive motor, preferably an electric motor, with an axially parallel drive arranged parallel to the steering rod, and the steering system includes a sensor, it is further preferred that the sensor be positioned at a distance from the drive element and that the entire path from the housing cover to the sensor maintains a minimum distance from the drive element. This minimum distance could be, for example, 10 cm, 15 cm, or 20 cm. In this case, the probability of steering system failure due to fluid penetrating through the housing cover is practically eliminated. The reliability of such a steering system is therefore very high.

[0018] If the steering housing according to the invention is part of a steering system according to the invention and / or if, in a steering system with a sensor, the sensor is provided in addition to a further sensor, the level of safety is even higher because the target drainage area provides for separate detection of fluid that penetrates the steering housing via a sleeve. This allows the distance to the target drainage area to be very short and the detection time to be kept low.

[0019] In another practical embodiment, the steering housing encloses a ball screw drive, an additional drive element, a traction drive, a steering rod with a rack section, and / or a steering rod with a threaded section. Alternatively or additionally, the sleeve encloses a connecting section between the steering rod and the tie rod. The steering system according to the invention was created particularly for steering systems with at least one, several, or all of these design features and offers particular advantages in conjunction with these features, especially when combined with further features shown in the following figures.

[0020] The invention also relates to a motor vehicle with a steering system as described above. The advantages already described above in connection with the respective steering system apply accordingly to such a motor vehicle, and reference is hereby made to them again.

[0021] Further practical embodiments of the invention are described below in connection with the drawings. They show: Fig. 1. A motor vehicle in a side view, Fig. 2. A steering system with a steering housing and a steering rod completely penetrating the steering housing with laterally adjoining tie rods in an isometric representation. Fig. 3 den in Fig. 2. Area marked III in an isometric representation, Fig. 4 the same area as in Fig. 3 in a longitudinal section view through the steering rod, Fig. 5 only the case cover from the Fig. 2 to 4 in an isometric view looking inside and Fig. 6. Remove the housing cover. Fig. 5 with a view of the outside.

[0022] Fig. Figure 1 shows a motor vehicle 10 with a front section 12 with steerable front wheels 14 in a side view. In the area of ​​the front section 12, between the steerable front wheels, is the Fig. 2 Steering system 16 shown in part. The steering system 16 comprises a steering rod 18 (cf. Fig. 3 and Fig. 4), which is surrounded in the central area by a steering housing 20 with a housing cover 22. A boot 24 adjoins the housing cover 22 and extends to a tie rod 26 protruding from the boot 24. A boot 24' is also arranged in the area of ​​the left end of the steering housing 20, from which another tie rod 26' protrudes.

[0023] In Fig. 3 is the one in Fig. 2 Area marked III enlarged and shown with semi-transparent steering housing 20. Fig. Figure 4 shows the same area in a longitudinal section view through the steering rod 18.

[0024] Both in Fig. 3 as well as in Fig. Figure 4 clearly shows that the steering rod 18 in the illustrated embodiment has a threaded section 28. This threaded section 28 extends externally to the right end of the steering rod 18, with the right end of the steering rod 18 protruding through the housing cover 22. As shown in the Fig. 3 and Fig. As can be clearly seen in Figure 4, the steering rod 18 is functionally connected to the tie rod 26 at its end in a known manner. In the illustrated embodiment, a receiving element 30 is connected to the steering rod 18. The receiving element 30 is designed in a ball-and-socket shape and engages a ball-shaped tie rod end 32 of the tie rod 26 such that a ball joint connection is established between the tie rod 26 and the steering rod 18.

[0025] As from the Fig. 3 and Fig. As can be clearly seen in Figure 4, a ball screw drive 34 with ball screw nut 36 is functionally connected to the threaded section 28 of the steering rod 18. By turning the ball screw nut 36, the steering rod 18 can be moved axially to the right or left in order to set a desired steering angle at the wheels 14 via the tie rods 26, 26' and the steerable wheels 14 functionally connected thereto.

[0026] In the embodiment shown, a belt 38 is provided for the complete or partial drive of the ball screw nut 36, which is coupled via a drive pulley 40 and a functionally coupled drive element 42 in the form of an electric motor 44.

[0027] A first sensor (not shown) is located in the area of ​​the steering housing 20 labeled S1. A second sensor (not shown) is located in the area of ​​the steering housing 20 labeled S2. Both sensors are liquid sensors capable of detecting even small amounts of liquid accumulating in their respective areas.

[0028] In the Fig. 5 and Fig. 6 is the one in each of the Fig. 2-4 visible lids 22 looking at the inside ( Fig. 5) and looking outwards ( Fig. 6) each shown in an isometric representation.

[0029] As can be seen from a synthesis of the Fig. 5 and Fig. As 6 results, a partially annular, inwardly projecting rib 46 is provided on the inside of the housing cover 22. In addition, a further rib 48 is provided, extending from one end of the partially annular rib 46, which extends in the transverse direction (y-direction) of the housing cover 22 to the opposite end.

[0030] The semi-circular rib 46 extends over a large part of the circumference of a round, here circular, opening 50. This is the upper part of the housing cover 22 when viewed in the vertical direction (z-direction) of the vehicle, so that only in the lower part of the opening 50 remains a free space over an angle α of approximately 40 degrees. Any fluid (not shown) that enters the circular opening 50 via the sleeve 24 is thus initially forced downwards by the semi-circular rib 46 in the direction of the acceleration due to gravity acting in the direction of arrow g, before it can move laterally through the free space extending over the angle α in the direction of arrow Q towards a designated drainage area 52. In the illustrated embodiment, the designated drainage area 52 is a recess 54 located on the side of the circular opening 50 opposite the housing cover 22 when viewed in the transverse direction.The further rib 48 is essentially linear in such a way that it extends slightly downwards from the circular opening 50 in the lower area of ​​the housing cover 22, so that liquid is safely guided from the further rib 48 to the recess 54 through the free space extending over the angle α.

[0031] From the recess 54, any fluid that has penetrated the housing cover then flows into the steering housing 20, where, after a relatively short flow path, it can be detected by the sensor located in area S1. To achieve this, the sensor located in area S1 can be positioned directly below the recess 54, or one or more additional ribs (not shown) or one or more recesses (also not shown) can be provided to guide the fluid within the steering housing 20, thus directing it in a controlled and targeted manner to the sensor located in area S1.

[0032] Both the sensor itself, located in area S1 (not shown), and the entire flow path from the circular opening 50 to area S1 maintain a minimum distance of 5 cm, and in this case even 10 cm, from the drive element 42. This ensures that any fluid entering the steering housing 20 via the housing cover 22 is reliably detected before it can damage the drive element 42.

[0033] The housing cover 22 is preferably made of plastic. More preferably, the housing cover with the inwardly projecting ribs 46, 48 shown is made in one piece from plastic. Alternatively, the ribs 46, 48 can also be made of another, in particular a softer, material, for example by manufacturing the housing cover 22 as a two-component injection-molded part, in which a softer material, in particular a silicone or an elastomer, is used for the ribs 46, 48 to ensure a long-lasting and elastic seal.

[0034] For the sake of completeness, it should also be noted that in the illustrated embodiment, the cuff 24 is attached to the housing cover 22 by means of a clamp 56. The housing cover 22 is screwed to the steering housing 20 via three screw holes 58.

[0035] The features of the invention disclosed in the present description, the drawings, and the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. Reference symbol list 10 motor vehicle 12 Front section 14 steerable wheels 16 Steering system 18 Handlebar 20 steering housings 22 Case covers 24 cuff 24' cuff 26 tie rod 26' tie rod 28 thread section 30 recording element 32 Tie rod end 34 Ball screw drive 36 Ball screw nut 38 belts 40 Drive pulley 42 Drive element 44 Electric motor 46 partially annular ribs 48 more ribs 50 opening 52 Target flow area 54 In-depth study 56 bell 58 Screw-on opening S1 area in which a sensor is located S2 area, in which another sensor is located QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2008 041 303 A1

[0003] DE 10 2017 207 094 A1 [0004, 0006] US 2020 / 0088553 A1

[0005]

Images