Power steering assembly with targeted and adjustable compensation of impact pulses from the road side to the steering transmission and method for setting a power steering assembly

Abstract

The present invention relates to a power steering assembly for electromechanical power steering of a motor vehicle (10), particularly a commercial vehicle, the power steering assembly having a steering transmission (1), wherein the steering transmission (1) is configured to transmit rotational motion (III) introduced by a steering transmitter, particularly by a steering wheel (15) via the input side (2) of the steering transmission (1), particularly via the input shaft (3) of the steering transmission (1), to the output side (4) of the steering transmission (1), and wherein the power steering assembly is configured to convert the motion (I) derived from the output side (4) of the steering transmission (1) into rotational motion (V) of at least one wheel (17; 19) of the motor vehicle (10) about a steering axis (18). According to the proposal, an adjustable absorption unit (23) is provided for at least partially absorbing roadside impacts received by the wheels (17; 19) of the motor vehicle (10), and a separate pretensioning unit (24) is also provided. The separate pretensioning unit (24) is arranged to work in conjunction with the adjustable absorption unit (23) such that a predetermined pretension force is applied to the adjustable absorption unit (23). The invention also relates to a method for assembling a power steering assembly for an electromechanical power steering system in a motor vehicle (10).

Description

Technical Field

[0001] This invention relates to a power steering assembly for an electromechanical power steering system in a motor vehicle. Furthermore, this invention relates to a method for installing a power steering assembly for an electromechanical power steering system in a motor vehicle. Background Technology

[0002] Numerous power steering assemblies are known from the prior art. Here, power steering assemblies primarily include several mechanically load-sensitive components in the steering transmission mechanism mounted within the power steering assembly. Thus, the steering transmission mechanism typically has, for example, a screw and a ball-ring nut with a ball or ball chain, and further has toothed mating parts, for example, in the form of external teeth in the ball-ring nut, which engage with segmented teeth of a segmented shaft. These components are particularly sensitive to suddenly introduced mechanical forces or loads.

[0003] The source of such a sudden load is, for example, an impact pulse from the roadside. Therefore, unevenness in the road can cause impacts in a motor vehicle, which can, for example, lead to unintended sudden movements in the power steering assembly. In the prior art, typically only the shock absorber system of the wheel suspension is responsible for compensating for roadside impacts. However, such a system deserves improvement in that it can also more specifically compensate for or absorb loads or stresses introduced into sensitive components of the steering transmission.

[0004] The following explanation uses a commercial vehicle as an example, which should not be construed as limiting the invention. Commercial vehicles typically have power steering systems with ball-recirculating steering mechanisms. For this purpose, the power steering system has a steering transmission mechanism configured to transmit rotational motion introduced by a steering transmitter, i.e., by the steering wheel via the input side of the steering transmission mechanism, to the output side of the steering transmission mechanism. Here, the input side can be formed, for example, by an input shaft, and the output side can be formed, for example, by an output shaft in the form of a segmented shaft. Within the steering transmission mechanism, the rotational motion introduced by the input shaft can then be conventionally converted, for example, by the following: the input shaft is constructed as a screw, and its rotational motion causes translational motion of a ball-recirculating nut surrounding a section of the screw, wherein this translational motion can also be referred to as axial motion of the ball-recirculating nut or piston. The ball-recirculating nut is typically provided with external teeth. The ball-recirculating nut can then ensure, by means of the external teeth engaging with the segmented teeth of the segmented shaft, that the translational motion of the ball-recirculating nut is converted into rotational motion of the segmented shaft or output shaft and thus exported on the output side of the steering transmission mechanism. Connected to the output side, a steering arm is typically provided, and a pushrod is articulatedly attached to the steering arm. The pushrod of the power steering assembly ultimately receives the rotational motion derived from the output side of the steering transmission and performs a translational pushrod movement—also known as axial movement—even during steering. Here, this translational pushrod movement causes a conventional rotational movement of at least one wheel of the vehicle about the steering axis.

[0005] In a power steering assembly constructed in this way, roadside impacts can cause sudden movements in multiple components of the power steering assembly, which in turn result in undesirable loads or stresses introduced into the steering transmission. To date, such forces or loads and stresses in existing power steering assemblies have typically been compensated primarily by the hydraulic system of the power steering assembly.

[0006] Typically, in the prior art, designing such power steering components for specific applications requires significant investment. Therefore, very precise and expensive design and manufacturing methods are often necessary to correctly define the switching points of the damping elements that might be installed for the steering transmission or power steering component. This leads to the problem that indirect steering behavior can occur when a single, theoretically mounted component is not properly designed or manufactured. The steering transmission for the power steering component must be designed in a time- and cost-intensive, customized, and application-specific manner to avoid such negative effects, such as indirect steering behavior. For these reasons, the corresponding methods for setting up power steering components in the prior art are very laborious. Summary of the Invention

[0007] Against this backdrop, the objective of this invention is to extend the power steering assembly of the type mentioned at the beginning by providing better protection of the steering transmission from roadside impact pulses. Furthermore, it aims to reduce design and manufacturing costs and to avoid indirect steering behavior in the simplest possible way. Therefore, this invention also aims to provide a method for setting up a power steering assembly for electromechanical power steering in motor vehicles, which requires less expense to effectively avoid indirect steering behavior.

[0008] This task is solved by a power steering assembly featuring the characteristics of the present invention. Alternatively, this task is solved by a method featuring the characteristics of the present invention. The technical solutions of the present invention disclose other, particularly advantageous configurations of the invention.

[0009] The key consideration is that the power steering assembly is configured such that, within its framework, its adjustable damping unit is conventionally configured to specifically protect the steering transmission from loads or stresses generated by impact pulses from the roadside. To this end, the adjustable damping unit specifically compensates for such movement and the resulting load by specifically converting kinetic energy into potential energy. This reduces the forces or loads in the steering transmission that would not be substantially damped or weakened in the absence of the adjustable damping unit, or would only be damped or compensated by the hydraulic system of the power steering. Therefore, the adjustable damping unit is configured to convert kinetic energy into potential energy and ensure targeted cushioning or absorption of vibrations. Preferably, the adjustable damping unit is elastically constructed for this purpose. The adjustable damping unit is advantageously arranged such that it allows at least a small relative movement between adjacent components of the power steering assembly and those adjacent to the adjustable damping unit.

[0010] Furthermore, it is important for the present invention that the disadvantages described in the prior art can be avoided by additionally providing a separate pretensioning unit, which can be used to adjust the adjustable absorption unit. Therefore, a pretension force tailored to the specific application can be adjusted in the adjustable absorption unit by simply compressing the adjustable absorption unit to the desired degree. Thus, the adjustable absorption unit can be adjusted precisely in such a simple manner, effectively preventing indirect steering behavior. This also significantly reduces the cost of manufacturing the power steering assembly and, in particular, designing the power steering assembly. Therefore, particularly precise and expensive design and manufacturing methods are no longer required to correctly define the switching point of the adjustable absorption unit. Thus, even if the component is not correctly designed or manufactured, indirect steering behavior can be effectively avoided by simply pretensioning the adjustable absorption unit to the desired degree by the separate pretensioning unit.

[0011] The proposed power steering assembly for electromechanical power steering in motor vehicles includes a steering transmission, particularly for commercial vehicles. The steering transmission is configured to transmit rotational motion, introduced by a steering transmitter via the input side of the steering transmission, to the output side of the steering transmission. The steering transmitter may, in particular, be a steering wheel. The introduced rotational motion may, in particular, be introduced via the input shaft of the steering transmission. The proposed power steering assembly is configured to convert the motion derived from the output side of the steering transmission into rotational motion of at least one wheel of the motor vehicle about a steering axis.

[0012] The proposed power steering assembly is characterized by having an adjustable shock-absorbing unit for at least partially absorbing road-side impacts received by the vehicle's wheels. Furthermore, it is proposed to include a separate pretensioning unit that works in conjunction with the adjustable shock-absorbing unit, such that a predetermined pretension force is applied to the adjustable shock-absorbing unit.

[0013] The method according to the invention for setting up a power steering assembly for an electromechanical power steering system for a motor vehicle, particularly for setting up a power steering assembly according to the invention, as described above or below, such as the power steering assembly according to the invention.

[0014] The proposed method is characterized by integrating an adjustable absorbing unit into the entire power steering assembly's steering motion conversion system. This adjustable absorbing unit is used to at least partially absorb road-side impacts received via the vehicle's wheels. Furthermore, according to the proposal, a separate pretensioning unit is provided, and a predetermined pretension force is finally applied to the adjustable absorbing unit by compressing it.

[0015] In principle, the adjustable absorption unit can be compressed at least partially (in the case where the adjustable absorption unit is formed by multiple elastic elements arranged in different ways, such as at least one elastic element or a group of elastic elements) to an arbitrary, desired, and predetermined degree. Here, "arbitrarily" should of course be understood as within certain limits, i.e., within the range adaptable to the structural space. Specifically, for example, either a single compensating disc or multiple compensating discs of a defined thickness can be provided, which compress the adjustable absorption unit precisely at that thickness. Typically, for this purpose, it is preferable to simply press the adjustable absorption units together in the axial direction by individual pretensioning units, because the remaining usable structural space for the adjustable absorption unit is reduced due to the arrangement of the compensating discs. Alternatively, pretensioning nuts can also be provided as separate pretensioning units or other configured components having threads that engage with mating threads. Then, the degree of compression of the adjustable absorption unit can be advantageously adjusted in a personalized manner by screwing the threaded component into the mating thread to the desired degree, and thus compressing the adjustable absorption unit to that degree.

[0016] In principle, the proposed, adjustable absorption unit is specifically integrated into and is a component of the power steering assembly. For this purpose, the absorption unit can be integrated, for example, into the conversion system of the entire assembly's steering motion, i.e., between the input side of the steering transmission and, for example, the pushrod responsible for steering, when viewed from the steering transmitter (i.e., the steering wheel) in the direction of the wheel to be steered.

[0017] As a result, sudden movements in the proposed power steering assembly are advantageously compensated for in a targeted manner by an adjustable absorption unit, and the resulting load is at least partially absorbed. In this way, when an impact pulse, or the resulting force from the road, is transmitted either via the wheel to, for example, a pushrod and, if necessary, to other components of the power steering assembly adjacent to, for example, the pushrod, or also via the housing of the steering transmission, the impact pulse can be specifically buffered or compensated. Thus, the hydraulic system of the power steering assembly is no longer solely responsible for compensating for road-side impact pulses, and therefore the steering transmission of the proposed power steering assembly, and especially the sensitive components arranged within it, are better protected from road-side impact pulses.

[0018] In principle, the input side of the steering transmission can be formed by an input shaft, which can be particularly constructed as a screw. Typically, the output side of the steering transmission can be formed by an output shaft, preferably a segmented shaft. The motion derived from the output side of the steering transmission can be transmitted directly or indirectly from the output side, for example, via the segmented shaft, to, for example, a pushrod. Therefore, the output shaft can be securely, especially torsionalally or rotationally fixed, connected to, for example, the steering arm. The steering arm can then receive the rotational motion of the output shaft and also perform rotational motion. A ball joint can then be provided, for example, at the end of the steering arm opposite to the output shaft, connecting the steering arm to the pushrod. Accordingly, the ball joint ensures that the motion derived from the output side of the steering transmission is transmitted to the pushrod in the form of rotational motion of the output shaft and therefore, rotational motion of the steering arm, for performing translational pushrod motion.

[0019] In such an embodiment with a pushrod, the pushrod is thus configured to receive motion derived from the output side of the steering transmission and to perform a translational pushrod movement, wherein the pushrod is arranged such that the translational pushrod movement causes at least one wheel of the motor vehicle to rotate about the steering axis.

[0020] In principle, the adjustable absorption unit can be advantageously arranged such that it is integrated into the steering transmission and preferably positioned between the input and output sides of the steering transmission. In principle, the adjustable absorption unit can be constructed as an elastic element, such as an elastomer or a spring assembly, or multiple elastic elements can be provided as the adjustable absorption unit. In principle, the relative movement of adjacent components can be permitted by one or more elastic elements of the adjustable absorption unit, thereby receiving kinetic energy by means of the adjustable absorption unit, achieving the desired compensation effect. In principle, it is preferable that the adjustable absorption unit is formed by at least one elastic element, particularly by at least one disc spring and / or by at least one coil spring and / or by at least one elastomer.

[0021] In principle, the steering transmission can be advantageously configured with an input shaft and a ball recirculating nut. The input shaft is constructed as a screw, and the ball recirculating nut converts the rotational motion of the input shaft into translational motion. A toothed section is arranged to surround the ball recirculating nut on the outside. An adjustable absorption unit can be arranged such that the translational motion of the ball recirculating nut is transmitted to the toothed section via the adjustable absorption unit, and vice versa. In this way, roadside impact pulses can be effectively compensated within the steering transmission itself, particularly advantageously.

[0022] Furthermore, alternatively or additionally, the steering transmission can be advantageously configured with an input shaft and a ball recirculating nut. The input shaft is constructed as a screw, and the ball recirculating nut is used to convert the rotational motion of the input shaft into translational motion. An adjustable absorbing unit is at least partially configured as an axially resilient screw support for the input shaft. In this way, road-side impact pulses can be effectively compensated, particularly advantageously, on the input side of the steering transmission.

[0023] Additionally, it can be advantageously provided that the adjustable absorption unit, configured as an axially resilient screw support for the input shaft, is formed by at least one elastic element, particularly by at least one disc spring, wherein the at least one elastic element is arranged in the housing adjacent to the bearing assembly of the input shaft for rotatably supporting the input shaft, such that the bearing assembly of the input shaft is elastically received in the housing via the at least one elastic element in the axial direction. "Elastically in the axial direction" should be understood particularly with respect to the input shaft in the axial direction. It has been unexpectedly recognized through this invention that, despite the additional structural cost in the form of supplementing the bearing assembly of the input shaft, the economy of the entire power steering assembly can be improved. This is because it advantageously and specifically protects the sensitive components of the steering transmission from roadside impact pulses and thus increases their lifespan.

[0024] In principle, it can also be advantageously configured such that the input shaft, constructed as a screw, consists of at least one screw section facing the ball recirculating nut and an input section, and the screw section and input section are rotatably fixed but axially elastically connected to each other via an adjustable absorbing unit, which forms an axially elastic screw support for the input shaft, preferably in the form of at least one elastic element, particularly preferably in the form of a ring spring. Through this invention, it has been unexpectedly recognized that, despite the additional structural cost of dividing the input shaft, and primarily despite the practical weakening of the input shaft and thus the entire power steering assembly, the lifespan of the entire power steering assembly can be increased. This is because it advantageously and specifically protects the sensitive components of the steering transmission from roadside impact pulses.

[0025] A preferred embodiment of the power steering assembly is characterized in that the individual pretensioning unit includes at least one first compensation disc. This allows for the personalized configuration of the pretension force acting on the adjustable absorption unit in a particularly simple manner. Personalized adaptability to the application of the power steering assembly is possible without the need for laborious design of individual components, especially the elastic elements of the adjustable absorption unit. Furthermore, inaccuracies can be effectively compensated for during the manufacture of the power steering assembly. Preferably, the first compensation disc forms a contact surface with the adjustable absorption unit or some of its elastic elements as a mating surface.

[0026] Additionally, it is preferable that the individual pretensioning unit further includes at least one second compensation disc. In particular, the second compensation disc may have a second thickness, which differs from the first thickness of the first compensation disc. This allows for particularly simple adaptation to the specific application of the power steering assembly. Personalized adaptability to the application of the power steering assembly is possible without the need for laborious design of individual components, especially the elastic elements of the adjustable absorption unit. Furthermore, inaccuracies can be effectively compensated for during the manufacture of the power steering assembly. Preferably, the first compensation disc and the second compensation disc are arranged in a manner that they are directly abutting each other.

[0027] According to another embodiment of the power steering assembly, a separate pretensioning unit includes a pretensioning nut. This allows for a particularly simple and personalized configuration of the pretension force acting on the adjustable absorption unit. Personalized adaptability to the application of the power steering assembly is possible without the need for laborious design of individual components, especially the elastic elements of the adjustable absorption unit. Furthermore, inaccuracies can be effectively compensated for during the manufacture of the power steering assembly. Preferably, the pretensioning nut can be easily further screwed into a mating thread to increase the pretension force. More preferably, the pretensioning nut has an end face that forms a direct contact surface with the adjustable absorption unit or some of its elastic elements as a contact surface.

[0028] According to another embodiment of the power steering assembly, a separate pretensioning unit is configured to work in conjunction with an adjustable absorption unit, such that a predetermined pretension force can be adjusted, preferably substantially steplessly, by means of two components engaged with each other via threads and mating threads. "Substantially stepless" should be understood here as meaning that arbitrarily high or low values ​​cannot be used; that is, the components cannot be twisted relative to each other to an arbitrary degree, but rather can be twisted relative to each other within a certain range. Furthermore, if the components are twisted relative to each other, small steps can occur in the generated pretension force. In this respect, the term "stepless" should not be interpreted absolutely. Thus, personalized adaptation of the pretension force can be achieved in this way.

[0029] According to another embodiment of the power steering assembly, the individual pretensioning unit and the adjustable absorption unit are at least partially movable relative to each other in the axial direction during assembly. This ensures effective compensation for impacts to the roadside.

[0030] In another embodiment of the power steering assembly, the individual pretensioning unit is secured in the assembled state, particularly by a retaining bolt engaged in a slot, to prevent rotation in the circumferential direction. This ensures the reliability of the uniform compensation effect of the adjustable absorption unit and effectively prevents undesirable adjustments to the pretension force.

[0031] According to another embodiment of the power steering assembly, a separate pretensioning unit has an end face that forms a contact surface for direct contact with the adjustable absorption unit in order to apply a predetermined pretension force to the adjustable absorption unit. This ensures an effective and uniform transmission of pretension force from the pretensioning unit to the adjustable absorption unit.

[0032] A preferred embodiment of the method for setting up a power steering assembly is characterized by providing at least one first compensation disc as a separate pretensioning unit adjacent to the adjustable absorption unit, for pretensioning by targeted compression of the adjustable absorption unit. This allows for a particularly simple and personalized configuration of the pretensioning force acting on the adjustable absorption unit. Personalized adaptability to the application of the power steering assembly is possible without the need for laborious design of individual components, especially the elastic elements of the adjustable absorption unit. Furthermore, inaccuracies can be effectively compensated for during the manufacture of the power steering assembly. Therefore, the method is effective and simple. Preferably, the first compensation disc forms a contact surface with the adjustable absorption unit or some of its elastic elements as a mating surface.

[0033] Further preferably, a second compensation disc can be provided adjacent to the adjustable absorption unit for pre-tensioning by targeted compression of the adjustable absorption unit. Here, the second compensation disc preferably has a second thickness, which differs from the first thickness of the first compensation disc. This allows for particularly simple adaptation to specific applications of the power steering assembly. Personalized adaptability to power steering assembly applications is possible without the need for laborious design of individual components, especially the elastic elements of the adjustable absorption unit. Furthermore, inaccuracies can be effectively compensated for during the manufacture of the power steering assembly. Preferably, the first compensation disc and the second compensation disc are arranged in a manner that they are directly abutting each other.

[0034] According to another embodiment of the method, a pretensioning nut is provided as a separate pretensioning unit adjacent to the adjustable absorption unit for pretensioning by targeted compression of the adjustable absorption unit. This allows for a particularly simple and personalized configuration of the pretensioning force acting on the adjustable absorption unit. Personalized adaptability to the power steering assembly application is possible without the need for laborious design of individual components, especially the elastic elements of the adjustable absorption unit. Furthermore, inaccuracies can be effectively compensated for during the manufacture of the power steering assembly. Preferably, the pretensioning nut can be easily further screwed into a matching mating thread to increase the pretensioning force. More preferably, the pretensioning nut has an end face that forms a direct contact surface with the adjustable absorption unit or some of its elastic elements as a contact surface.

[0035] According to another embodiment of the method, a predetermined pretension force is set by twisting a first and a second component of a separate pretensioning unit relative to each other. The first component has threads, and the second component engages with the first component and has mating threads. Preferably, the pretension force can therefore be adjusted substantially steplessly. "Substantially stepless" should be understood here as meaning that arbitrarily high or low values ​​cannot be used; that is, the components cannot be twisted relative to each other to an arbitrary degree, but can be twisted relative to each other within a certain range. Furthermore, if the components are twisted relative to each other, small steps can also occur in the resulting pretension force. In this respect, the term "stepless" should not be interpreted absolutely. Thus, personalized adaptation of the pretension force can be achieved in this way. The greater the degree of twisting of the components relative to each other, the higher the degree of compression of the adjustable absorption unit, that is, the higher the pretension force acting on the adjustable absorption unit.

[0036] According to another embodiment of the method, the individual pretensioning unit is finally fixed to prevent torsion in the circumferential direction.

[0037] Additionally, it is preferable to provide a fixing bolt that is form-fitted into the groove in the circumferential direction.

[0038] Therefore, effective compensation for impacts on the roadside is ensured. The reliability of the uniform compensation effect of the adjustable absorption unit is guaranteed by effectively preventing undesirable adjustments to the pretension force.

[0039] The features and advantages of the power steering component described above and below, which relate to the proposed method, can be transferred to the proposed method, and vice versa, where technically reasonable. Attached Figure Description

[0040] Further features and advantages of the invention will become apparent from the following description of the invention and its technical solutions, as well as embodiments which should not be understood in a limiting manner. These embodiments are now described in more detail with reference to the drawings, in which:

[0041] Figure 1 A schematic diagram of the steering transmission is shown.

[0042] Figure 2 Showing has Figure 1 A schematic diagram of a motor vehicle's steering transmission system.

[0043] Figure 3 Partially shown is the steering transmission device according to the proposed power steering assembly, in Figure 3 A) is shown in a schematic view, and in Figure 3 b) China and Israel Figure 3Sectional view AA in a) shows,

[0044] Figure 4 This shows a separate pretensioning unit constructed as a compensating disc.

[0045] Figure 5 Based on principle Figure 3 The cross-sectional view of section BB in a) partially shows the steering transmission device according to the proposed power steering assembly.

[0046] Figure 6 Based on principle Figure 3 The cross-sectional view of section BB in a) partially shows the steering transmission according to the proposed power steering assembly.

[0047] Figure 7 This shows the input axis according to the recommended power steering assembly, in Figure 7 a) is shown in perspective view in the assembled state. Figure 7 b) China and Israel Figure 7 The front view of direction B in a) is shown, and in Figure 7 c) According to Figure 7 The cross-sectional view of section AA in b) is shown, and

[0048] Figure 8 View of all individual parts in their unassembled state Figure 7 a) The input axis of the power steering component as recommended. Detailed Implementation

[0049] exist Figure 1 The diagram schematically illustrates a power steering assembly for an electromechanical power steering system used in a motor vehicle. The power steering assembly includes a steering transmission 1. Steering is driven by a steering transmitter, such as a steering wheel, via the steering transmission 1. Figure 1 (Not shown) The steering motion is performed by the driver of the motor vehicle. For this purpose, the rotational motion introduced via the input side 2 of the steering transmission 1, or via the input shaft 3 in the specific case, is transmitted to the output side 4 of the steering transmission 1.

[0050] On the output side 4 of the steering transmission 1, the movement of the output shaft 6 of the steering transmission 1, configured as a segmented shaft 5, is derived, in the specific case, as a rotational movement. Finally, in the currently shown non-limiting embodiment, this movement derived on the output side 4 is received by the pushrod 7 of the power steering assembly; this movement, in the currently shown case, is a rotational movement, indicated by two curved double arrows I. Thus, the pushrod 7 performs a translational pushrod movement. The translational pushrod movement of the pushrod 7 is... Figure 1The linear motion marked by double arrow II in the middle, and ultimately resulting in at least one wheel of the vehicle revolving around the steering axis (in Figure 1 (Not shown in the image) rotates, causing the vehicle to perform the desired turning maneuver.

[0051] In order to convert the rotational motion (double arrow I) derived on the output side 4 into the desired translational push rod motion (double arrow II) of the push rod 7, the power steering assembly shown has a steering arm 8 and a joint in the form of a ball joint 9 that connects the steering arm 8 to the push rod 7.

[0052] In order to describe the typical turning process below, not only refer to Figure 1 Also refer to Figure 2 , Figure 2 A schematic diagram of a motor vehicle 10 as viewed from below is shown, the vehicle having... Figure 1 The power steering assembly with steering transmission device 1 is included.

[0053] For motor vehicles 10 in the form of commercial vehicles, ball-recirculating steering transmissions are typically used as so-called ball-recirculating steering systems (abbreviated as KUL). The kinematics of such a component are particularly advantageous for commercial vehicles because such components mostly have a front axle in the form of a rigid shaft. If the longitudinal steering gear and pushrod of the front axle are approximately the same length and arranged substantially parallel to each other, the longitudinal steering gear and the pushrod form a parallelogram. Thus, the compressive motion of the front axle has little or no effect. As long as the steering transmission 1 is mounted in a frame-fixed manner, the length compensation in the steering column can be achieved, for example, through the corresponding relative motion between the frame of the motor vehicle 10 and the cab. Since commercial vehicles involve applications in which the proposed power steering assembly is particularly suitable, the invention will be explained below using a ball-recirculating steering system as an example.

[0054] The steering transmission 1 includes an input shaft 3, segmentally constructed as a screw 11, and a ball recirculation nut 13 arranged in the region of the screw 11, the ball recirculation nut having external teeth 12. A segmented toothed portion 14 engages with the external teeth 12. The segmented toothed portion 14 and the external teeth 12 are arranged in a meshing manner. Furthermore, the segmented toothed portion 14 is also rotatably and torsionally connected to an output shaft 6, which is therefore constructed as a segmented shaft 5. The steering arm 8 is rotatably and torsionally connected to the output shaft 6, wherein the steering arm 8 is movably connected to a push rod 7 via a ball joint 9 as previously described.

[0055] In the steering transmission device 1, the steering transmitter, specifically the steering wheel 15 ( Figure 2The rotation of the input shaft 3 is transmitted to the screw 11 via the steering column and input shaft 3. The input shaft 3 may be, for example, part of the steering column. The screw 11 is also referred to as a ball-recirculating screw or possibly a worm gear. This rotational motion of the input shaft 3 is... Figure 1 The rotational motion is marked by arrow III, which indicates circular motion. This rotational motion is converted into linear motion of the ball recirculating nut 13 by means of the ball recirculating nut 13, and therefore also into linear motion of the external teeth 12 of the ball recirculating nut 13. This linear motion of the ball recirculating nut 13 and the external teeth 12... Figure 1 The middle part is marked with a double arrow IV.

[0056] Then, through the mating of the teeth of the external toothed portion 12 and the segmented toothed portion 14, the linear motion marked by double arrow IV is converted into the rotational motion of the output shaft 6, as described, which is derived on the output side 4 of the steering transmission 1. This rotational motion is marked by the curved double arrow I. Therefore, the linear motion (double arrow IV) is ultimately also converted into the rotational motion of the steering control arm 8 (double arrow I). At the end of the steering control arm 8, the push rod 7 moves primarily linearly. Through the push rod 7, as from... Figure 2 As can be seen, the steering rod 16, which is fastened to the wheel carrier, ultimately causes the wheel 17 to swing around the steering axis 18. This rotational motion of the wheel 17... Figure 2 The V-shaped arrow is indicated by a curved double arrow. Here, the other wheel 19, opposite wheel 17, can be steered together via the steering tie rod arm 20 and the rigid steering tie rod 21.

[0057] Reference Figure 1 As can be seen, the rotational motion (double arrow I) derived from the output side 4 is transmitted to the push rod 7 via the ball joint 9, causing the push rod 7 to perform a translational push rod motion (double arrow II) to perform the steering motion of the wheel 17 or the wheels 17 and 19 in a conventional manner.

[0058] exist Figure 2 The image also shows the frame 22 of the motor vehicle 10, which is in the form of two longitudinal beams arranged parallel to each other. The steering transmission 1 can be achieved by means of... Figure 1 and 2 Fastening components, not shown, are mounted on the frame 22 of the motor vehicle 10, for example, by means of longitudinal beams of the frame 22 and the housing of the steering transmission 1 connected to each other by fastening screws. The driving direction of the motor vehicle 10 is... Figure 2 The arrow VI is used to mark it.

[0059] Preferably, the steering transmission 1 has a hydraulic power steering assist device. For this purpose, the ball recirculation nut 13 is sealed relative to the housing of the steering transmission 1. Therefore, the ball recirculation nut 13 can be used as a so-called hydraulic piston, or simply referred to as a piston. Accordingly, the ball recirculation steering device has two separate oil chambers on opposite sides of the piston for hydraulic steering assistance. Then, by means of the steering torque introduced by the driver on the input shaft 3, a differential pressure can be established between the two sides of the ball recirculation nut 13, for example, by means of a rotating spool valve. This differential pressure assists the movement of the ball recirculation nut 13.

[0060] To achieve the desired steering motion, the described power steering assembly, particularly in the steering transmission 1, has multiple mechanically load-sensitive components. These components need protection primarily against sudden movements, which can occur, for example, due to vibrations and ultimately undesirable forces introduced via the wheels 17, 19 into the steering transmission 1. Such forces, loads, or stresses may occur in the system when, for example, uneven road surfaces cause impacts introduced via the wheels 17, 19. In this regard, it is particularly worthwhile to dampen or compensate for such roadside impact pulses toward the steering transmission 1, and thus prevent damage to the components of the steering transmission 1. Specifically, in the illustrated embodiment, such harmful impacts may be further transmitted to the steering transmission 1 via the wheels 17, 19 and then via the pushrod 7, thereby potentially damaging the sensitive components of the steering transmission 1.

[0061] Here, the present invention provides a remedy in an advantageous manner. For this purpose, it is important to provide an adjustable absorption unit 23 for absorbing impacts received by the wheels 17, 19 of the motor vehicle 10 on the roadside.

[0062] Here, the adjustable absorption unit 23 can be disposed at different parts or nodes of the power steering assembly, such as exemplarily in Figures 3 to 8 As can be seen in the illustrated embodiment. Here, the adjustable absorption unit 23 is preferably formed by at least one energy-absorbing element and is configured to convert kinetic energy at least partially into potential energy.

[0063] Therefore, the adjustable absorption unit 23 is preferably integrated into the power steering assembly, such that the components of the power steering assembly adjacent to the adjustable absorption unit 23 can undergo at least minimal movement relative to each other. For this purpose, the adjustable absorption unit 23 is preferably constructed elastically, or has increased flexibility compared to adjacent, especially directly adjacent, components. In this way, sudden movements can be selectively received by the components in the power steering assembly within the adjustable absorption unit 23 and buffered or compensated by it. The targeted relative movement allowed in the components in the form of the adjustable absorption unit 23 ensures targeted energy conversion and thus ensures compensation for kinetic energy. In this way, the risk of damage to mechanically load-sensitive components in the steering transmission 1 is significantly reduced.

[0064] Here, the adjustability of the adjustable absorption unit 23 is ensured by a separate pre-tensioning unit 24. This separate pre-tensioning unit 24 works in conjunction with the adjustable absorption unit 23, thereby applying a predetermined pre-tension force to the adjustable absorption unit 23. In particular, the separate pre-tensioning unit 24 is used to compress or squeeze the adjustable absorption unit 23 together to a certain extent. Therefore, when the separate pre-tensioning unit 24 is present, compared to the state where the separate pre-tensioning unit 24 is absent or not assembled, the adjustable absorption unit 23 has a relatively small thickness dimension, particularly in the direction of the force flow of the force introduced by the impact from the roadside, which is to be compensated. Thus, a targeted restoring force is generated within the adjustable absorption unit 23.

[0065] An adjustable absorbing unit 23 for absorbing or compensating for roadside impacts received via the wheels 17 of the motor vehicle 10 can be installed at different locations on the power steering assembly. However, as per... Figure 3 , 5 As will become clear from the following embodiments 6, 7, and 8, the adjustable absorption unit 23 can be integrated particularly effectively into the steering transmission 1 or into the attachment between the steering transmission and the input shaft 3. Particularly preferably, the adjustable absorption unit 23 is incorporated here into the construction of the ball recirculation nut 13 or into the interaction between the ball recirculation nut and the input shaft 3 (see...). Figure 3 , 5 ), or set during the support of input shaft 3 (see Figure 6 ) or it can be set in the construction of the input shaft 3 itself (see Figure 7 , 8 ).

[0066] exist Figure 3 In a), the steering transmission device 1 is shown schematically in part. Figure 3 b) shows Figure 3Sectional view AA in a). Figure 3 a) Used as a schematic overview (different alternative reference numerals are given in parentheses), because Figure 5 as well as Figure 6 It is also shown in principle Figure 3 Sectional view BB in a).

[0067] According to Figure 5 The implementation is the same as the previous one. Figure 3 (b) Partially shown is the steering transmission 1 of the corresponding power steering assembly according to the proposed power steering system. Here, in both embodiments, the steering transmission 1 has an input shaft 3 configured as a screw 11, and further has a ball recirculating nut 13 and a rack 55 for converting the rotational motion (arrow III) of the input shaft 3 into translational motion (double arrow IV).

[0068] To transmit this translational motion (double arrow IV), the rack 55 has a toothed section 56 on its outer side, which provides external teeth 12. The toothed section 56 or the external teeth 12 then engages with the segmented shaft 5, which at least partially forms the output side 4 of the steering transmission 1, and the toothed section or external teeth, through its translational motion (double arrow IV), induces the desired rotational motion of the segmented shaft 5 (see [link to original text]). Figure 1 (Double arrow I in the image). Additionally, the rack 55 is constructed as a separate component relative to the internally located ball recirculating nut 13.

[0069] To compensate for the impact on the roadside, in Figure 3 b) and Figure 5 The adjustable absorption unit 23 of the power steering assembly shown is arranged such that the translational movement of the ball recirculation nut 13 (double arrow IV) is transmitted to the tooth section 56 via the adjustable absorption unit 23, and vice versa, that is, the translational movement of the tooth section 56 is also transmitted to the ball recirculation nut 13 via the adjustable absorption unit 23. Here, the adjustable absorption unit 23 is formed by at least one elastic element, more specifically, according to... Figure 5 In the implementation variant, the adjustable absorption unit is formed by two disc springs 57, or according to... Figure 3 In the implementation variation of b), it is formed by two elastic bodies 58. In principle, a combination of elastic bodies, disc springs, or helical springs is also possible.

[0070] The adjustable absorption unit 23 is ultimately formed at the connection between the corresponding ball circulation nut 13 and the toothed section 56, which serves as the outer toothed section 12 for toothed mating with the segmented shaft 6.

[0071] In the direction corresponding to the translational movement of the ball recirculating nut 13 (double arrow IV), the ball recirculating nut 13 and the rack 55 with toothed section 56 are, in principle, arranged in a manner movable relative to each other. In the rotational direction, that is, in principle corresponding to the rotational movement of the input shaft 3 (arrow III), the ball recirculating nut 13 and the rack 55 with toothed section 56 are fixed in a manner anti-torsional relative to each other. That is, the ball recirculating nut 13 cannot be rotated within the receiving portion of the rack 55 for the ball recirculating nut. For this purpose, a sliding key can be provided, for example, for fixing. Figure 5 The ball 60 of the ball circulation steering device is additionally shown in the image, while... Figure 3 b) Omits the explicit illustration of the sphere.

[0072] In the illustrated embodiment, the adjustable absorption units 23, each formed by at least one elastic element, allow relative movement of the components adjacent to the adjustable absorption units 23. These relative movements are possible in the axial direction. Here, the adjustable absorption units 23 are subjected to elastic compression. In this way, in the event of excessive or sudden movement, such as from impacts on the roadside, for example, a sudden torsion of the output shaft 6, the adjustable absorption units 23 conventionally convert kinetic energy into potential energy. Thus, the loads present within the steering transmission 1 and caused by impacts on the roadside can be advantageously compensated.

[0073] exist Figure 3 b) and Figure 5 In the two illustrated embodiments, the ball recirculating nut 13 is received in a central bore of the rack 55 having a plane 61 and is secured on the opposite side of the plane 61 by means of a cap 62. For this purpose, the cap 62 stops at the end face of the rack 55 with its head-side, surrounding support surface, the end face of which is arranged opposite to the plane 61 of the central bore.

[0074] The covers 62 are securely connected to the rack 55, preferably via the ends of the rack 55 opposite to the plane 61. Furthermore, according to... Figure 5 In one embodiment, the cover 62 has an axially extending inlet section 59 that extends into the central bore of the rack 55.

[0075] According to Figure 3 In embodiment b), the elastomer 58 shown on the left abuts against the inner portion of the circumferential support surface on the head side of the cover 62 via its left, outer end face. According to... Figure 5 In one embodiment, the disc spring 57 shown on the right abuts against the inner end face of the guide section 59 of the cover 62 by means of its right, outer surface.

[0076] Below, through Figure 3 b) and Figure 5 The two embodiments described herein describe the compensating effect of sudden movements caused by roadside impacts using an adjustable absorption unit 23. Specifically, this mainly relates to the following situation: a sudden movement of the output shaft 6 occurs, which may cause a rapid linear movement of the rack 55 in two directions indicated by double arrows IV, the rack engaging the output shaft 6 via tooth mating (see reference numerals 12, 14, 56).

[0077] In principle, Figure 3 b) and Figure 5 In both embodiments, this is manifested as follows: a sudden twisting of the segmented shaft 5 and therefore a sudden linear movement of the rack 55 to the left, in Figure 3 In the embodiment shown in b), compensation is first achieved by the elastomer 58 shown on the right, and in Figure 5 In the embodiment shown, compensation is first achieved by the disc spring 57 shown on the right. The same applies to the sudden linear movement of the corresponding ball recirculating nut 13, which results in compression of the elastomer 58 on the right or the disc spring 57 on the right.

[0078] Conversely, for the opposite direction of movement, the left elastic body 58 or the left disc spring 57 is compressed when the corresponding ball recirculating nut 13 moves sharply to the left, thereby achieving the desired compensation in a targeted manner. Similarly, for the sharp rightward offset of the output shaft 6 and therefore the segmented gear 14, the left elastic body 58 or the left disc spring 57 is compressed by the sharp linear rightward movement of the corresponding rack 55, thereby achieving the desired compensation in a targeted manner.

[0079] Specifically, according to Figure 3 In embodiment b), targeted compensation for sudden movements is performed as follows: if, for example, the rack 55 moves abruptly to the left, induced by a sudden leftward swing of the segmented shaft 5, this causes the right-hand elastic body 58 to be compressed first. This right-hand elastic body 58 is received in the central receiving portion 25 of the rack 55, where a compensation disc of the pretensioning unit 24 (described in more detail later) is first arranged at the bottom of the central receiving portion 25, and the right-hand elastic body 58 is abutted against this compensation disc. In any case, the sudden leftward movement is transmitted from the rack 55 through the bottom of the central receiving portion 25 and the pretensioning unit 24 to the right-hand elastic body 58, and subsequently through the adjacent annular element 63 to the ball recirculating nut 13.

[0080] The compensation for the sudden leftward movement of the rack 55 described herein works in a similar manner in the opposite direction of the force flow, i.e., when the cause of this sudden movement is not the leftward offset of the output shaft 6 and therefore the segmented teeth 14 as described above, but more precisely, the rightward sudden movement of the ball recirculating nut 13. This is because the ball recirculating nut 13, moving suddenly to the right, first compresses the right-hand elastic 58 via the motion transmission through the annular element 63 before the right-hand elastic body then transmits the movement, as desired, to the pretensioning unit 24 or finally to the rack 55 and ultimately to the segmented teeth 14 and the output shaft 6.

[0081] In the opposite direction, that is, when rack 55 moves suddenly to the right (for example, caused by a rapid rightward offset via segmented shaft 5), firstly, in Figure 3 In b), the cover 62 shown on the left edge moves to the right because it is securely connected to the rack 55. Thus, the adjacent left-hand elastic body 58 is compressed first before the movement is transmitted to the ball recirculating nut 13 via the annular element 63.

[0082] The compensation described also works in the opposite direction of the force flow, i.e., when the starting point is not a sudden rightward movement of the rack 55, but a rapid leftward movement of the ball recirculating nut 13. This is because the desired compensation is achieved first by compressing the adjacent left-side elastic body 58 via the annular element 63, before the force and motion are transmitted to the cover 62 and thus to the rack 55 and output shaft 6.

[0083] according to Figure 5 In this embodiment, targeted compensation for sudden, impact-induced motion is performed as follows: if, for example, rack 55 moves abruptly and linearly to the left, for instance due to a sudden leftward offset of segment 5, the right disc spring 58 is compressed first. This is achieved by the cap 62, which is firmly connected to the rack, along with its lead section 59, moving to the left along with rack 55. Thus, before finally transmitting motion to the ball-recirculating nut 13, which is connected to the right disc spring 57 on the left, the right disc spring 57 is compressed first, resulting in the desired compensation for impacts to the roadside.

[0084] The compensation for the sudden leftward movement of rack 55 described herein works in a similar manner in the opposite direction of the force flow, i.e., when the cause of this sudden movement is not the leftward offset of output shaft 6 and therefore segmented teeth 14 as described above, but more precisely, the rightward sudden movement of ball recirculation nut 13. This is because the ball recirculation nut 13, moving suddenly to the right, first compresses the right disc spring 57 before the right disc spring then transmits the motion to cover 62, which in turn transmits it to rack 55 and finally to segmented teeth 14.

[0085] In the opposite direction, that is, when rack 55 according to Figure 5 When a sudden rightward movement is performed, the left disc spring 57, located in the area of ​​plane 61, is compressed first before the corresponding load is transmitted to the ball recirculation nut 13. Similarly, a sudden leftward rushing movement of the ball recirculation nut 13 causes the left disc spring 57 to be compressed first before the force and thus the movement are finally transmitted to the rack 55 via the plane and ultimately cause the leftward offset of the segmented teeth 14 and the output shaft 6.

[0086] A particular advantage of the proposed power steering assembly is the inclusion of a separate pretensioning unit 24 that works in conjunction with an adjustable absorption unit 23. The desired, predetermined pretension force is applied by this separate pretensioning unit 24 to the adjustable absorption unit 23.

[0087] According to Figure 3 b) and Figure 5 In the illustrated embodiment, specifically, the first compensation disc 26 is used as a separate pretensioning unit 24. Figure 4 A first compensation disc 26 is shown in principle, having a first thickness d1. A second compensation disc 27, with a different (smaller) thickness d2, is also shown. Compensation discs 26 and 27 each have a central opening 28. In the assembled state, the ball recirculation nut 13 and the input shaft 3 (see [link to image]) are also present. Figure 3 b) or just input axis 3 (see b) Figure 5 It can extend through the opening.

[0088] In principle, multiple compensation disks 26 and 27 can also be set up, instead of the one shown in the original text. Figure 3 b) and Figure 5 Only one first compensation disc 26 is provided as a separate pretensioning unit 24, as exemplarily shown, in particular in order to selectively adjust the desired pretension force that can act on the adjustable absorption unit 23.

[0089] Specifically, the individual pretensioning unit 24, in the described embodiment, has a corresponding first compensation plate 25 with an end face 29, which serves as a contact surface with the adjustable absorption unit 23 for adjusting, i.e., pretensioning the absorption unit 23. The first compensation plate 25 and the corresponding adjustable absorption unit 23 are arranged in abutment against each other via the contact surface.

[0090] Specifically, in Figure 3 In b), the first compensation disc 26 is received in the central receiving portion 25 of the rack 55. An elastic body 58, adjustable for the right side of the absorption unit 23, is arranged on the side opposite to the bottom of the central receiving portion 25. This right elastic body 58 is connected to the end face 29 of the first compensation disc 26 of the separate pretensioning unit 24 via its outer surface on its right end face (see [link]). Figure 4 )touch.

[0091] Compared to the case without the first compensation disc 26, the separate pretensioning unit 24 with the first compensation disc 26 ensures compression of the adjustable absorption unit 23, or more specifically, compression of the right-hand elastic body 58, in this way. That is, a predetermined pretension force is applied to the adjustable absorption unit 23, which in turn induces a restoring force in the adjustable absorption unit 23.

[0092] That is, the power steering assembly can be advantageously configured by means of the proposed method for configuring an electromechanical power steering assembly for motor vehicle 10, wherein this may primarily involve the power steering assembly described above, in that an adjustable absorption unit 23 is first integrated into the conversion system of the steering motion of the entire power steering assembly for at least partially absorbing roadside impacts received by the wheels 17 or 19 of motor vehicle 10.

[0093] Then, as recommended, a separate pretensioning unit 24 is set up. Here, as in... Figure 3 , 5 As in embodiment 6, at least one first compensation disc 26 can be provided as a separate pretensioning unit 24 adjacent to the adjustable absorption unit 23 for pretensioning by selectively compressing the adjustable absorption unit 23. Alternatively, a second compensation disc 27 can be provided adjacent to the adjustable absorption unit 23 for pretensioning by selectively compressing the adjustable absorption unit 23 (see [reference]). Figure 4 Advantageously, the second compensation disk 27 may have a second thickness d2, which is different from the first thickness d1 of the first compensation disk 26.

[0094] With the aid of such a separate pretensioning unit 24, a personalized, predetermined pretension force is ultimately set according to the recommended method. This pretension force is applied to the adjustable absorption unit 23 by the separate pretensioning unit 24 compressing the adjustable absorption unit 23. Here, the adjustable absorption unit 23 is compressed to a predetermined degree. This degree may be, for example, as in... Figure 3 , 5 In embodiments 6, the selection is preferably made by the thickness of the selected compensation disks 26 and 27, for example by the first thickness d1 of the first compensation disk 26 (see...). Figure 4 The compression and therefore the pretension can also be adjusted by, for example, screwing in the pretension nut 30, thereby ensuring essentially stepless adjustability (see [link]). Figure 7 and 8 (and corresponding descriptions).

[0095] exist Figure 6 , 7 Figure 8 shows another embodiment of the adjustable absorption unit 23 according to the proposed power steering assembly. In the illustrated embodiment, the steering transmission 1 has an input shaft 3 and a ball recirculation nut 13, the input shaft being constructed as a screw 11, the ball recirculation nut being used to convert the rotational motion (arrow III) of the input shaft 3 into translational motion (double arrow IV). Here, the adjustable absorption unit 23 is at least partially formed as an axially resilient screw support for the input shaft 3.

[0096] According to Figure 6 In this embodiment, the adjustable absorption unit 23, which forms the axial elastic screw support of the input shaft 3, is formed by two elastic elements, specifically by disc springs 67 and 68. Here, disc springs 67 and 68 are arranged in the housing 70 adjacent to the bearing assembly (specifically, a double row of angular contact ball bearings 69) of the input shaft 3 for rotatably supporting the input shaft 3, such that the bearing assembly of the input shaft 3 is elastically received in the housing 70 via the disc springs. A separate pretensioning unit 24, having a first compensation disc 26, is arranged between the left disc spring 67 and the angular contact ball bearing 69.

[0097] By means of the adjustable absorbing unit 23, which is shown in the form of two disc springs 67 and 68, impacts from the roadside can be specifically compensated, for example, via a segmented shaft 6 having segmented teeth 14. Therefore, the sleeve surrounding the input shaft 3 and the inner ring of the angular contact ball bearing 69 rotate together with the input shaft 3 (arrow III). The outer ring of the angular contact ball bearing 69 is arranged anti-rotationally, but axially movable, within the steering transmission housing 70.

[0098] Adjustable absorption units 23, in the form of disc springs 67 and 68, are attached to the outer ring of the angular contact ball bearing 69 on both sides (i.e., disc spring 67 on the left and disc spring 68 on the right). However, the disc spring 67 on the left is attached to the outer ring of the angular contact ball bearing 69 only indirectly, not directly. Therefore, a first compensation disc 26 is also arranged between the disc spring 67 and the outer ring of the angular contact ball bearing 69.

[0099] As suggested, in the event of an impact on the screw side, axial damped movement occurs because the disc spring 67 shown on the left is compressed when the input shaft 3 moves suddenly to the left, and the disc spring 68 shown on the right is compressed when the input shaft 3 moves suddenly to the right. The inner diameters of the disc springs 67 and 68 are larger than the diameter of the sleeve or the input shaft 3. Therefore, small relative movements of adjacent components of the power steering assembly are selectively allowed again by the adjustable absorption unit 23 shown, which in turn ensures that kinetic energy is selectively converted into potential energy and thus also ensures compensation for roadside impacts. Here, a separate pretensioning unit 24 with a first compensation disc 26 ensures targeted pretensioning of the disc spring 67 shown on the left.

[0100] According to Figure 7 and 8 In one embodiment, the input shaft 3, configured as a screw 11, is constructed in a multi-part configuration via at least one screw section 71 and an input section 72 facing the ball-shaped recirculating nut 13. Figure 7 In diagram a), input shaft 3 is shown in perspective view in its assembled state, while Figure 7 b) according to Figure 7 The front view of arrow B in a) shows the corresponding input axis 3. Figure 7 In c), then in the corresponding Figure 7 The input shaft 3 is shown in the longitudinal section of section AA in section b). Figure 8 The same input shaft 3 is shown again, but in an unassembled state, i.e., to illustrate that it is shown as a disassembled individual component.

[0101] The screw section 71 and input section 72 of the input shaft 3 are rotatably and fixedly connected to each other. However, the screw section 71 and input section 72 are also axially elastically connected to each other via an adjustable absorption unit 23, which forms an axial elastic screw support for the input shaft 3. Here, the axial elastic screw support is formed by elastic elements, more specifically, in the present case, by the annular spring assembly 73 shown on the left and the annular spring assembly 91 on the right.

[0102] For this purpose, the annular spring 73 shown on the left is arranged between the screw section 71 and the input section 72. Specifically, the annular spring 73 shown on the left is received in the central receiving portion 74 on the end 75 of the screw section 71 facing the input section 72. On the side opposite to the bottom of the receiving portion 74, the annular spring 73 abuts against the end face 76 of the connecting push rod 77. The connecting push rod 77 is also mostly received in the receiving portion 74 of the screw section 71; however, the end 78 of the connecting push rod 77 facing the input shaft 3 in the input section 72 extends from the receiving portion 74 and thus from the end 75 of the screw section 71.

[0103] The connecting push rod 77 ensures a torsional connection between the screw section 71 and the input section 72 of the input shaft 3. For this purpose, as described, the connecting push rod 77 is received in the receiving portion 74 of the screw section 71 and the receiving portion 79 of the input section 72, respectively, and is rotatably and fixedly connected to the corresponding components. To this end, a connecting pin 80 is provided on the screw side, which, in the assembled state, extends not only through the elongated hole 81 in the screw section 71 but also through the through-hole 82 on the screw side of the connecting push rod 77 (for clarity, only...). Figure 8 (The through bore 82 is marked in the middle). Therefore, the elongated hole 81 is also constructed as a through bore. Thus, the elongated hole 81 and the through bore 82 on the screw side conform to each other in the assembled state. The elongated hole 81 has a larger axial extension dimension about the axis of the input shaft 3 than the through bore 82 on the screw side.

[0104] On the side facing the input section 72, the connecting push rod 77 also has a through hole 83 on the input side (for clarity, only...). Figure 8 (The through-hole 83 is marked in the middle). Furthermore, the input section 72 of the input shaft 3 also has a through-hole 84, which, in the assembled state, corresponds to the through-hole 83 on the input side. In the assembled state, the connecting pin 85 on the input side extends not only through the through-hole 84 but also through the through-hole 83 on the input side, causing the input section 72 and the connecting push rod 77 to be rotatably and fixedly connected to each other. Furthermore, the input section 72 and the connecting push rod 77 are also fixedly connected to each other axially, because both the through-hole 84 and the through-hole 83 on the input side have substantially the same diameter, and the connecting pin 85 on the input side causes the two components to be form-locked together when viewed in the axial direction.

[0105] With the described arrangement, the input section 72 and the screw section 71 are rotatably and fixedly connected to each other by means of the connecting pin 80 on the screw side, the connecting pin 85 on the input side, and the connecting push rod 77. Here, between the two ends of the two components facing each other, that is, between the end 75 of the screw section 71 facing the input section 72 and the end 86 of the input section 72 facing the screw section 71, there is sufficient clearance space for a small axial relative movement between the screw section 71 and the input section 72. Also, since the connecting pin 80 on the screw side is received in the elongated hole 81 of the screw section 71 in a manner with axial clearance space, the connecting push rod 77 can therefore move axially relative to the screw section 71.

[0106] Such small axial relative movements are conventionally utilized to dampen or compensate for impact pulses from the roadside. This is ultimately achieved using an adjustable absorption unit 23, which takes the form of a ring spring 73 shown on the left and a ring spring assembly 91 shown on the right. The ring spring shown on the left is arranged in the receiving portion 74 of the screw section 71, resting against the end face 76 of the connecting push rod 77. By receiving the relative movement through the adjustable absorption unit 23, kinetic energy is conventionally converted into potential energy, thus compensating for impacts from the roadside.

[0107] Furthermore, as suggested, a pretensioning nut 30 is provided as a separate pretensioning unit 24. The pretensioning unit 30 partially surrounds the connecting push rod 77 on the outside. The annular spring 91 of the annular spring assembly 91 shown on the right is arranged to engage with the pretensioning nut 30 in the axial direction. Specifically, the annular spring 91 shown on the right is also arranged to surround the connecting push rod 77. Here, the annular spring 91 is arranged on the left side, i.e., in the direction pointing towards the screw section 71, to abut against the axial push rod abutment portion 31. On the right side, i.e., in the direction pointing towards the input section 71, the annular spring 91 is arranged to abut against the axial end face 32 of the pretensioning nut 30. That is, the axial end face 32 of the pretensioning nut 30 forms the contact surface between the annular spring 91 of the adjustable absorption unit 32 and the separate pretensioning unit 24.

[0108] exist Figure 7 and Figure 8 In the embodiment shown, the two interlocking threads are part of a separate pretensioning unit 24. Thus, on one hand, the pretensioning nut 30 has threads 33 on its outer side surface (for clarity, only...). Figure 8(Indicated by arrows). On the other hand, the screw section 71 of the input shaft 3, which is partially hollow internally constructed, has a mating thread 34 that matches the thread 33. In this way, the pretensioning nut 30, as the first component, and the screw section 71 of the input shaft 3, as the second component, engage with each other. Thus, the individual pretensioning unit 24 is arranged in such a way as to work with the adjustable absorption unit 23 that the predetermined pretension force can be adjusted by means of the two components engaged with each other via the thread 33 and the mating thread 34, which are in the form of the pretensioning nut 30 and the screw section 71. Here, in the current case, the two components can be adjusted substantially steplessly. Thus, the axial position of the pretensioning nut 30 relative to the screw section 71 of the input shaft 3 can be arbitrarily changed at least within a certain range.

[0109] Depending on the extent to which the pre-tensioned nut 30 is brought into the receiving part 74 of the screw section 71 and finally rotated into the mating thread 33, the right-hand annular spring assembly 91 is compressed to a stronger or weaker degree.

[0110] To secure the pre-tensioned nut 30 and prevent re-twisting of the thread 33 in the mating thread 34, an anti-twisting device can be provided as shown. For this purpose, in Figure 7 and 8 In the embodiment shown, the pretensioning nut has a groove 35. Multiple grooves may also be provided at different locations on the side surface of the pretensioning nut 30. To prevent torsion, a retaining bolt 36 is provided in the assembled state, which engages not only in the groove 35 of the pretensioning nut 30 but also in a drilled hole 37 on the side surface of the screw section 71 of the input shaft 3 (see [link]). Figure 7 (c) and overview of 8). By receiving the retaining bolt 36 in a form-locking manner in the bore 37 and similarly receiving the retaining bolt 36 in a form-locking manner in the circumferential direction in the slot 35, the pre-tensioning nut 30 is secured against torsion, i.e., connected to the screw section 71 of the input shaft 3 substantially torsionally or rotationally fixed.

[0111] Viewed in the axial direction, the pretension nut 30 is arranged to surround the internally located connecting push rod 77 in such a way that the pretension nut 30 can move axially relative to the connecting push rod 77. That is, the pretension nut 30 can change position relative to the connecting push rod 77 in the axial direction. Therefore, although the position of the pretension nut 30 relative to the screw section 71 is fixed in both the axial and circumferential directions, at least a small axial relative movement of the screw section 71 of the input shaft 3 relative to the connecting push rod 77 and therefore relative to the input section 72 of the input shaft 3 is possible, as described in detail previously. The axial movement clearance space is also given by the fact that the slot 35 is constructed as an elongated hole in which the retaining bolt 36 can reciprocate to some extent along the axial direction.

[0112] The pretension nut 30 presses against the axial contact surface of the annular spring 91 by means of its axial end face 32, thereby compressing the annular spring together and thus applying the desired, predetermined pretension force to the adjustable absorption unit 23 by the compression of the annular spring 91.

[0113] Therefore, in accordance with the recommendations for setting up Figure 7 and 8 The power steering assembly shown in the middle section is configured such that a pretensioning nut 30 is positioned as a separate pretensioning unit 24 adjacent to the adjustable absorption unit 23, specifically to the ring spring assembly 91 on the right and particularly to the axial contact surface 38 of these ring springs 91, for pretensioning by selectively compressing the adjustable absorption unit 23. Here, a predetermined pretension is set by twisting a first component of the separate pretensioning unit 24, in the form of a pretensioning nut 30, and a second component, in the form of a screw section 71 of the input shaft 3, relative to each other. The first component has a thread 33, and the second component engages with the first component and has a mating thread 34. The degree to which the thread 33 is screwed into the mating thread 34 determines the degree of compression of the ring springs 91 and thus the set pretension.

[0114] The power steering assembly shown advantageously compensates for roadside impacts in such a manner that the input section 72 of the input shaft 3 is supported in its position both axially and radially. Impacts acting on the screw 11 are damped or compensated by the annular spring assembly 73 or 91. If, for example, the screw 11 moves to the right in the direction of the input section 72, the left annular spring assembly 73 is first compressed before that movement is finally transmitted to the connecting push rod 77 and thus to the input section 72 of the input shaft 3.

[0115] The following compensation is made for sudden movements of the input section 72 of the input shaft 3, which could cause it to move either to the left (towards the screw section 71) or to the right (away from the screw section 71): As the input section 72 moves to the left, the connecting push rod 77 also moves to the left, thus compressing the left-side annular spring assembly 73 before the movement is transmitted to the screw section 71. Conversely, when the input section 72 moves to the right, the connecting push rod 77 also moves to the right, thus compressing the right-side annular spring assembly 91 first via the axial push rod abutment 31. This movement is then transmitted to the pretension nut 30 via the axial end face 32 of the pretension nut 30 and thus also to the screw section 71, which is securely connected to the pretension nut 30.

[0116] Finally, a protective sleeve 87 is provided on the outer side, which also has a through hole 88 on the screw side and a through hole 89 on the input side. The through hole 88 on the screw side corresponds to the through hole 82 on the screw side of the connecting push rod 77 and the elongated hole 81 in the screw section 71. In addition, the connecting pin 80 on the screw side also extends through the through hole 88 on the screw side of the protective sleeve 87. The through hole 89 on the input side corresponds to the through hole 83 on the input side of the connecting push rod 77 and the through hole 84 in the input section 72. In addition, the connecting pin 85 on the input side also extends through the through hole 89 on the screw side of the protective sleeve 87.

[0117] Therefore, the protective sleeve specifically surrounds the connecting push rod 77 on the outside and also surrounds the axial free space between the screw section 71 and the input section 72. Furthermore, the protective sleeve ensures guidance on the outside of the two separately implemented components of the input shaft 3, namely the screw section 71 and the input section 72.

[0118] List of reference numerals

[0119] 1. Steering transmission device

[0120] 2 (Input side of steering transmission 1)

[0121] 3 Input axis

[0122] 4 (Output side of steering transmission 1)

[0123] 5-segment shaft

[0124] 6 Output shaft

[0125] 7. Putter

[0126] 8. Steering arm

[0127] 9. Ball joint

[0128] 10 Motor vehicles

[0129] 11 Screw

[0130] 12 (External teeth of ball recirculating nut 13)

[0131] 13 Ball recirculating nut

[0132] 14 (Segmented shaft 5) Segmented teeth

[0133] 15. Steering wheel

[0134] 16. Steering rod

[0135] Wheels 17 and 19 (of motor vehicle 10)

[0136] 18 Steering axis

[0137] 20 Steering tie rod arm

[0138] 21. Steering tie rod

[0139] 22 (of motor vehicles 10) frames

[0140] 23 Adjustable absorption units

[0141] 24 Pre-tensioning units

[0142] 25 (Rack 55) Central Receiving Section

[0143] 26 First Compensation Plate

[0144] 27 Second Compensation Plate

[0145] 28 Opening

[0146] 29 (end face of pretensioning unit 24)

[0147] 30 Pre-tensioned nut

[0148] 31 Axial push rod contact part

[0149] 32 (end face of pre-tensioning nut 30)

[0150] 33 thread

[0151] 34 Mating Thread

[0152] 35 slots

[0153] 36 fixed bolt

[0154] 37. Drilling on the side surface of the screw section 71

[0155] 38 (Axial contact surface of ring spring 91)

[0156] 55 rack

[0157] 56 Tooth Section

[0158] 57 Disc Spring

[0159] 58 Elastomers

[0160] 59 (of the cover 61) axially extending lead section

[0161] 60 balls

[0162] 61 (the plane of the central hole in rack 55)

[0163] 62 lids

[0164] 63 Ring element

[0165] Disc springs 67 and 68

[0166] 69 Angular contact ball bearing (double row)

[0167] 70 (Steering transmission unit) housing

[0168] 71 (Input shaft 3) Screw section

[0169] 72 (Input section of input axis 3)

[0170] 73. Ring spring

[0171] 74 (receiving section of screw section 71)

[0172] 75. The end of screw section 71 (facing input section 72)

[0173] 76 (the end face of the connecting push rod 77)

[0174] 77 Connecting push rod

[0175] 78 The end of the connecting push rod 77 (facing the input section 72)

[0176] 79 (Receiving section of input segment 72)

[0177] 80 Connecting pin on the screw side

[0178] 81 (elongated hole in screw section 71)

[0179] 82 (Through-drilled hole on the screw side of the connecting push rod 77)

[0180] 83 (through hole on the input side of connecting push rod 77)

[0181] 84 (Input section 72) Through borehole

[0182] 85 Input side connection pin

[0183] 86. The end of input section 72 (facing screw section 71)

[0184] 87 Protective Sleeve

[0185] 88. Through-hole on the screw side (of the protective sleeve)

[0186] 89. Through-hole (on the input side of the protective sleeve)

[0187] 91. Ring spring

Claims

1. A power steering assembly for an electromechanical power steering system in a motor vehicle (10), the power steering assembly having a steering transmission device (1), wherein, The steering transmission (1) is configured to transmit a rotational motion (III) introduced by a steering transmitter via an input shaft (3) of the steering transmission (1) through the input side (2) of the steering transmission (1), the input shaft (3) being at least segmentally constructed as a screw (11), and the steering transmission (1) including a ball recirculating nut (13) for converting the rotational motion (III) of the input shaft (3) into linear motion (IV), and wherein the power steering assembly is configured to transfer the rotational motion from the output side (4) of the steering transmission (1) The derived motion (I) is converted into rotational motion (V) of at least one wheel (17; 19) of the motor vehicle (10) about the steering axis (18), wherein an adjustable absorption unit (23) is provided for at least partially absorbing roadside impacts received by the wheels (17; 19) of the motor vehicle (10), wherein a separate pretensioning unit (24) is provided, the separate pretensioning unit (24) being arranged in conjunction with the adjustable absorption unit (23) such that a predetermined pretension force is applied to the adjustable absorption unit (23), wherein at least one of the following characteristics is satisfied: (i) The steering transmission (1) further comprises a rack (55) for converting the rotational motion (III) of the input shaft (3) into linear motion (IV), the rack (55) having a toothed section (56) on the outer side, the toothed section (56) surrounding the ball recirculation nut (13) on the outer side, and the rack (55) being a separate component relative to the ball recirculation nut (13). The ball recirculation nut (13) and the rack (55) are arranged in a movable manner relative to each other in the direction corresponding to the linear motion (IV) of the ball recirculation nut (13), wherein the adjustable absorption unit (23) is arranged between the relatively movable components in the form of the ball recirculation nut (13) and the rack (55) and integrated into the structure of the ball recirculation nut (13) in such a way that the linear motion (IV) of the ball recirculation nut (13) is transmitted to the toothed section (56) via the adjustable absorption unit (23), and vice versa; or (ii) The adjustable absorption unit (23) is configured as an axial elastic screw support for the input shaft (3) and is composed of at least one elastic element (67; 68), wherein the at least one elastic element (67; 68) is arranged adjacent to the outer ring of the bearing assembly (69) of the input shaft (3), the bearing assembly for rotatably supporting the input shaft (3) in the housing (70), such that the bearing assembly (69) of the input shaft (3) is elastically received in the housing (70) axially via the at least one elastic element (67; 68); or (iii) The adjustable absorption unit (23) is configured as an axially elastic screw support for the input shaft, wherein the input shaft (3) is constructed in multiple parts by at least one screw section (71) facing the ball recirculating nut (13) and an input section (72), and wherein the screw section (71) and the input section (72) are rotatably and fixedly connected to each other, however, the screw section (71) and the input section (72) are also axially elastically connected to each other via the adjustable absorption unit (23).

2. The power steering assembly according to claim 1, characterized in that, The individual pretensioning unit (24) includes at least one first compensation disc (26).

3. The power steering assembly according to claim 2, characterized in that, The separate pretensioning unit (24) also includes at least one second compensation disc (27).

4. The power steering assembly according to any one of claims 1 to 3, characterized in that, The individual pretensioning unit (24) includes a pretensioning nut (30).

5. The power steering assembly according to any one of claims 1 to 4, characterized in that, The separate pretensioning unit (24) is configured to work in conjunction with the adjustable absorption unit (23) so that the predetermined pretension force can be adjusted by means of two components that engage with each other via a thread (33) and a mating thread (34).

6. The power steering assembly according to any one of claims 1 to 5, characterized in that, The individual pretensioning unit (24) and the adjustable absorption unit (23) are at least partially movable relative to each other in the axial direction in the assembled state.

7. The power steering assembly according to any one of claims 1 to 6, characterized in that, The individual pretensioning unit (24) is fixed in the assembled state to prevent rotation in the circumferential direction.

8. The power steering assembly according to any one of claims 1 to 7, characterized in that, The individual pretensioning unit (24) has end faces (29; 32) that form a contact surface for direct contact with the adjustable absorption unit (23) in order to apply the predetermined pretension force to the adjustable absorption unit (23).

9. The power steering assembly according to claim 3, characterized in that, The second thickness of the second compensation disk is different from the first thickness (d1) of the first compensation disk (26).

10. The power steering assembly according to claim 7, characterized in that, The individual pretensioning unit (24) is secured in the assembled state by a retaining bolt (36) engaged in the groove (35) to prevent rotation in the circumferential direction.

11. A method for setting up a power steering assembly for an electromechanical power steering system for a motor vehicle (10) according to any one of claims 1 to 10, characterized in that, An adjustable absorption unit (23) is integrated into the steering motion conversion system of the entire power steering assembly. The adjustable absorption unit is used to absorb at least partially the roadside impacts received by the wheels (17; 19) of the vehicle (10). In addition, a separate pretensioning unit (24) is provided, and a predetermined pretensioning force is finally set and applied to the adjustable absorption unit (23) in such a way that the separate pretensioning unit (24) compresses the adjustable absorption unit (23).

12. The method according to claim 11, characterized in that, At least one first compensation disc (26) is provided as a separate pretensioning unit (24) adjacent to the adjustable absorption unit (23) for pretensioning by selectively compressing the adjustable absorption unit (23).

13. The method according to claim 12, characterized in that, Furthermore, a second compensation disk (27) is provided adjacent to the adjustable absorption unit (23) for pre-tensioning by selectively compressing the adjustable absorption unit (23).

14. The method according to any one of claims 11 to 13, characterized in that, A pretensioning nut (30) is provided as a separate pretensioning unit (24) adjacent to the adjustable absorption unit (23) for pretensioning by selectively compressing the adjustable absorption unit (23).

15. The method according to any one of claims 11 to 14, characterized in that, The predetermined pretension force is set by twisting the first and second parts of the individual pretensioning unit (24) relative to each other, the first part having a thread (33) and the second part engaging with the first part and having a mating thread (34).

16. The method according to any one of claims 11 to 15, characterized in that, Finally, the individual pretensioning unit (24) is secured to prevent torsion in the circumferential direction.

17. The method according to claim 16, characterized in that, The fixing is achieved by setting a fixing bolt (36) which is shaped to engage in a groove (35) in the circumferential direction.

Images