WO2004067357A1

WO2004067357A1 - Motor vehicle steering gear comprising a gear rack and a bearing module therefor

Info

Publication number: WO2004067357A1
Application number: PCT/EP2004/000736
Authority: WO
Inventors: Friedhelm GÜNTHER
Original assignee: Schmitterchassis Gmbh
Priority date: 2003-01-28
Filing date: 2004-01-28
Publication date: 2004-08-12
Also published as: DE112004000167D2

Abstract

The invention relates to a bearing module (7) for a motor vehicle steering gear comprising a gear rack (11) and a driving pinion (15) which engages with said gear rack. Said bearing module (7) comprises at least one thrust collar (71) provided with a receiving borehole (76), the wall (78) of said borehole extending eccentrically in relation to the outer periphery (83) of the thrust collar (71) and/or an imaginary central axis (19) of the gear rack (11), and surrounding a guiding passage (87) for axially guiding the gear rack (11). Radial forces from the wall (78) of the borehole can be generated to press the gear rack (11) received in the guiding passage (87) against the driving pinion (15) engaging therein. The guiding passage (87) is directly defined by at least one separately formed guiding element (72, 75) which is arranged inside the receiving borehole (76), is supported on the wall (78) of the borehole in an elastic and/or sprung manner, and can thus be radially displaced against the elastic force at least by the extent of the eccentricity of the thrust collar (71) and/or for compensating said eccentricity.

Description

Motor vehicle steering gear with rack and bearing module therefor

The invention relates to a bearing module for a motor vehicle steering gear with a rack and drive pinion in engagement therewith. The bearing module has at least one pressure ring with a receiving bore, the bore wall of which runs eccentrically with respect to the outer circumference of the pressure ring and / or an imaginary central axis of the rack and surrounds a guide passage for axially guiding the rack. Starting from the bore wall, radial forces can be generated for the pressure of the rack received in the guide passage on the drive pinion engaging therein. Furthermore, the invention relates to a motor vehicle steering gear with such a bearing module, the guide passage of which comprises the toothed rack which engages with the drive pinion within a gear housing.

In a known steering gear with an eccentric rack mounting (DE-OS 2 409 938), the rack slides in a bearing ring with an eccentric bore. The resulting wedge bearing is rotatably mounted in the housing. When the rotary position is correct, the eccentric section of the bore lies against the rack, namely on the side opposite the teeth. It is also proposed to bias the eccentric bearing by a spring into its eccentric thrust position against the rack 15, the spring being biased and acting in the circumferential direction. The spring thus exerts a force rotating the bearing transversely to the radial direction, so that the eccentric bore with a wedge-like constriction slidably bears against the toothed rack on its side opposite the teeth. Due to the torque, a permanent catch-up should be created.

To avoid the disadvantages associated with this known, eccentric steering gear mounting, it is proposed in DE 100 04 710 A1 to form the rack bearing from at least one annular element and at least one eccentric bearing shell. The eccentric bearing shell is composed of two parts, of which at least one part has an elastomer layer or a spring element. Furthermore, the eccentric bearing shell is also intended to be a mechanical stop Form the limit of the insertion into the gearbox used for assembly. The eccentric bearing shell is placed on a housing inner wall, which concentrically or symmetrically surrounds the rack passage with its central axis.

In the rack and pinion steering known from DE 199 47 510 A1, a sleeve-shaped piston rod guide made of plastic is used as the end stop in order to achieve better noise behavior. The end of the piston rod guide facing the gear housing end forms the end stop for a stop ring of an adjacent tie rod joint. Consequently, the stop surface in combination with the stop ring results in the path limitation for the stroke of the steering gear and the associated steering angle. Further stop means penetrated by the rack in connection with steering gears are known from DE 100 45 820 A1.

The invention has for its object to provide a robust, insensitive to external shocks rack mounting and guidance for steering gear, which is characterized by a simplified assembly without the need for additional, manual settings. To solve the problem, the bearing module specified in claim 1 and the motor vehicle steering gear specified in claim 27, provided with the specified bearing module, are proposed. Within the framework of the general inventive idea is also a complementary pressure piece which can be integrated into the bearing module according to the invention as claimed in claim 20. Further advantageous configurations result from the dependent claims.

Through the use of additional guide parts according to the invention in combination with spring elements or integrated suspension, an elastic buffer can be created between the eccentric receiving bore of the pressure ring and the rack, which is exposed to impacts introduced via the roadway and the vehicle wheels. By the fact that the guide parts can be radially adjusted according to the invention, they can be displaced during assembly with simple handling and without the need for subsequent adjustment against the spring forces so that the wall of the bore of the eccentric pressure ring based on radial forces inward to push the rack onto the pinion. The rack can be used during assembly as a means to radially adjust the guide parts according to the eccentricity and thus adjust the spring biasing force.

Even during the manufacture of the bearing module, the spring constant or characteristic and the degree of eccentricity can be matched to one another in the sense of a specified preload so that further adjustments or adjustments are no longer required in the subsequent assembly in the steering gear housing.

In order to reduce the manufacturing outlay and to avoid irregular, costly to produce housing shapes, it is provided according to a special embodiment of the invention that the guide part or parts are arranged symmetrically or concentrically with respect to an imaginary line of symmetry or central axis (expediently running through the guide passage) or also symmetrically or are designed concentrically. It can thus be achieved that only symmetrical or regularly shaped and thus easier to manufacture components are required for the guide part (s), which reduces the manufacturing outlay. In a particularly advantageous development of this idea, at least one inner ring is arranged as a guide part within the eccentric receiving bore of the (outer) pressure ring and is resiliently supported on the bore wall thereof via one or more radially oriented, elastic pressure elements. The inner guide ring can be made rotationally symmetrical and thus be easy to manufacture in terms of production technology.

It corresponds to the rotational symmetry to be aimed at in the sense of simple, inexpensive manufacture, if, according to an inventive design, the resilient support or the elastic pressure element or elements are realized by one or more, radially deflectable spring ring elements. These can then be arranged parallel to the eccentric inner circumference of the pressure ring and / or in contact with the wall of the bore around the guide part or parts. To facilitate assembly and manageability is further an inventive design, according to which the pressure ring on one or both end faces has a plurality of radially inwardly projecting holding shoulders or elements for axially holding the guide part or parts. This allows the bearing module to be manufactured as a compact, stable, self-contained component that can be assembled quickly and reliably and that can be easily stored and handled independently of the other steering gear. In order nevertheless to ensure the radial adjustability of the guide parts in the sense of the invention, the axial holding of the guide parts is expediently implemented with play in order to prevent jamming.

The assembly handling and safety can be facilitated by an advantageous embodiment of the invention, according to which the outer jacket of the pressure ring is designed with one or more axial or axially parallel stop shoulders or ramps. When such a bearing module is inserted axially into a steering housing, these stop elements then serve as insertion limits when they encounter counter-stop shoulders on the inner wall of the steering gear housing.

By means of DE-OS 2 409 938 explained at the outset, the eccentric pressure ring forming a wedge bearing must be rotatably mounted in the housing so that the eccentric section bears against the toothed rack side which lies opposite the teeth by means of a rotary setting. This requires additional, time-consuming assembly and adjustment activities of high skill. To remedy this, an advantageous embodiment of the invention is proposed, according to which the outer casing of the pressure ring is provided with one or more, axially parallel orientation projections and depressions. These can then come into engagement with complementary recesses or elevations in or on the inner wall of the transmission housing when it is inserted into a steering gear housing during assembly. This mutually intermeshing, rail-like guide is positioned in the circumferential direction (with respect to the rack or housing center axis) such that when assembled with the rack and the drive pinion engaging in it Housing which are directed at the wall of the bore with eccentric thickening pressure forces on the outside of the rack or that rack outer shell section, which or which are diametrically opposed to the teeth of the rack meshing with the drive pinion. As a result, the correct orientation of the eccentric section of the pressure ring, namely opposite the tooth side of the rack, can be brought about quickly, easily and reliably.

The preassembled bearing module is expediently only axially pressed into the gearbox or main housing when the toothed / piston rod, expediently in engagement with the drive pinion, has already been inserted into the housing beforehand. In the assembled state, the arrangement according to the invention is characterized in that the central axis and / or the axis of symmetry of the guide part or parts of the bearing module coincide with that of the rack and / or the transmission housing tube and are offset eccentrically with respect to the central axis of the pressure ring receiving bore. In the course of pressing in, the guide part or parts, in particular the inner ring, are radially displaced from their position concentric with respect to the receiving bore before assembly by approximately the amount of the eccentricity applied by means of the toothed rack to the eccentrically thickened section of the pressure ring. A range between approximately 0.1 to 0.8 mm or 0.2 to 0.6 mm has proven to be a useful measure of eccentricity between the central axis of the toothed rack and the central axis of the pressure ring receiving bore.

Within the scope of the invention, there is the option of assembling the radially outer pressure ring, which surrounds the guide parts, from several individual parts. This enables the advantage of increased application flexibility with regard to different requirements and operating conditions to be achieved. In the case of the ring-like configuration, its individual parts can then easily be replaced by other individual parts that are specially tailored to the specific application.

With the bearing module described above, approx. 0.2 mm can be achieved for the toothed rack play under spring pressure (residual play). A uncontrolled block tension, in which the outer pressure ring would hit the inner ring, must be avoided. Otherwise the steering would become stiff and the pinion and pinion bearing would only have a short service life. This results in particular when particularly high mechanical loads on the vehicle to be steered are to be feared due to potholes, curbs and the like, and the spring pressure force due to the eccentricity applied according to the invention is exceeded by the rack on the pinion of 200 to 300 Newtons Requirement to achieve less than 0.05 mm for the rack pressure under spring pressure.

This problem is countered with an optional development of the invention in the storage module in such a way that the pressure ring is provided with at least one cutout, opening and / or interruption, in which at least one complementary supplementary pressure piece can be used. This is designed to bear against the or at least one of the guide parts in order to reduce its residual play. In continuation of this idea, the or at least one of the guide parts is provided with a contact surface which is assigned to the pressure piece and which runs obliquely in a wedge-like manner with respect to a central axis or axially parallel longitudinal direction or line of symmetry of the guide passage such that a self-locking or self-locking locking of the adjacent pressure piece occurs in the axial passage direction. This effect is based on the effect of self-locking known per se in mechanical engineering if the wedge or pitch angle is smaller than the effective friction angle, that is to say if the wedge-like pressure gap cannot jump out of the notch, which in the present case is due to the oblique guide part - Contact surface is formed on the one hand and by the inner wall of the gear housing on the other. In order to achieve the self-locking effect, an angle of inclination of 4 ° to 8 °, for example 6 °, in relation to the central axis or the longitudinal direction parallel to the axis or the line of symmetry of the guide passage has proven itself for the wedge-like contact surface.

Alternatively or additionally, the complementary pressure piece can rest on one or at least one of the elastic pressure pieces or spring elements. A complementary pressure piece according to the invention is characterized by a shape with two side sections which follow one another at an obtuse angle and which can be used for bearing against the or one of the guide parts and / or against the or one of the elastic pressure elements. A range from 120 ° to 160 °, for example 144 °, has proven useful for the obtuse angle.

According to an advantageous embodiment, the two side sections, which adjoin one another at an obtuse angle, jointly lie opposite one side of the pressing piece, with which they each enclose acute angles. Areas between 15 ° and 45 ° (for example 30 °) or 4 ° and 8 ° (for example 6 °) have proven useful for the latter.

In order to ensure correct assembly, that is to prevent incorrect insertion of the complementary pressure piece into the bearing module pressure ring, the complementary pressure piece according to the invention with orientation projections and / or is provided according to an advantageous option

To provide orientation indentations or recesses in the inner area. This enables a self-checking shape to be implemented that cannot be inserted incorrectly into a pre-specified contour. In an expedient concretization of this idea, the edge-side projections or indentations lie in a plane or circumferential surface that is common to the opposite side.

A simple and inexpensive way of producing the complementary pressure piece is by plastic injection molding.

It is within the scope of the invention that the spring ring elements mentioned above are radially and eccentrically compressed when the bearing module is installed in the gear housing via a circular piece or an arc which, seen in the radial direction, is congruent with the outside of the rack or the outer casing section and / or this outer side or this outer jacket section extends in parallel, which is diametrically opposite the teeth of the rack. In order to save on components and to reduce the space requirement and the necessary installation space, according to an embodiment of the invention, the bearing module is arranged in an end region of the gearbox housing in such a way that the pressure ring with an end face facing the housing end region has a stop surface for realizing a steering stroke. Limit can form, for example, with respect to an adjacent tie rod joint. For this purpose, it is expedient for the end face mentioned to be of the largest possible area. This can be done by means of an annular shoulder projecting radially inwards, which then engages behind the guide part or parts and fixes them axially, preferably with play.

Known O-rings, in particular made of elastomer material, are commercially available as inexpensive spring ring elements.

There is often a requirement to be able to use power steering systems with a steering gear in a temperature range of around -40 ° Celsius to 150 ° Celsius. It is important that the spring characteristic or spring characteristic does not change significantly when passing through such a temperature range, for example the spring ring element does not become particularly hard at low temperatures and does not become particularly soft at high temperatures. This can be countered in the context of the invention by using steel or another metal with properties that are relatively little temperature-dependent. Known radially compressible and expandable springs in helical or spiral form are conceivable within the scope of the invention for realizing such steel or metal ring spring elements. However, the disadvantage is that the length in the circumferential direction of a helical or spiral spring could lengthen or shorten depending on the radial interaction or expansion. Accordingly, in the case of a closed ring shape, the circumference must lengthen or shorten or the diameter must widen or decrease.

In the present application of the bearing module in a steering gear, the spring ring elements are enclosed between the pressure ring and the inner ring. The spiral or helical turns of a screw spring ring element would rub and / or skew on the inner wall of the correspondingly formed annular chamber between the pressure ring and the inner ring during the radial compression or separation. As a result, the problem arises that a helical or spiral spring closed in the manner of a ring can easily block in the bearing module according to the invention. The linearity of the resulting spring characteristic would not be guaranteed.

To remedy this, the spring ring element specified in claim 42 is proposed, which is characterized by a design with a plurality of elastic spring members, which are ring-shaped and are connected in a ring to form the spring ring element. The spring ring element is thus designed to form a spring ring chain with individual spring links. Each of these, independently of adjacent circular spring members, can expand or decrease in circumference without the length in the circumferential direction of the spring ring element thereby changing. Protection of the invention is hereby reserved for such a specially designed spring ring element. Advantageous, optional designs of this spring ring element according to the invention result from the dependent claims 43-53.

To promote the elastic, radial deflectability, the ring-like basic shape is designed with an opening or ring interruption, in particular in the manner of a C-shape. Their opposite opening ends can be adjusted to or from each other depending on the radial load. The opening forms a "mouth", so to speak, which can be opened and closed in an elastically deflectable manner. This effect is further promoted in that, according to a further embodiment, the ring openings of the spring members resulting from the C-shape are aligned parallel to the central axis of the entire spring ring element, The radial compressive and tensile forces can then be directed completely to the C-shaped body of the spring element. For this purpose, it is also expedient to incline the respective ring planes of the individual spring elements obliquely or perpendicularly to the ring plane of the entire spring ring element This also has the advantage that the individual spring members can deform elastically without that an extension or shortening of the entire spring ring element in the circumferential direction would be necessary.

The last-mentioned point of view serves a further development of the invention, according to which connecting webs between two adjacent, connected spring members extend from the ends of the C-type spring member, which delimit the respective openings. With spring deflection in the radial direction, the openings can narrow or widen without the connecting webs having to be deformed in the spring ring element circumferential direction or axially parallel to the individual spring C spring members.

In order to be able to produce the specific design of the spring ring element according to the invention with simple manufacturing steps with little effort, it is proposed according to a special embodiment to use a flat and / or flat blank made of steel or other metal, first to give it the shape of a circular ring and then alternately from the radially outside to the inside and from the radially inside to the outside slots or notches. In the next manufacturing step, the inner and outer peripheral edges are then to be bent towards each other in the radial direction in such a way that - seen in the axial longitudinal section - the C-shapes are created for the individual spring members.

Further details, features, advantages and effects based on the invention result from the following description of preferred embodiments of the invention and from the drawings. These show in:

FIG. 1 shows a steering gear housing in a longitudinal view,

FIG. 2 shows a sectional view along line A-A in FIG. 1, but in the fully assembled state,

FIG. 3 shows a sectional view along line BB in FIG. 1, FIG. 4 shows the detail IV outlined in FIG. 2, namely the longitudinal section of the storage module according to the invention,

5 shows the bearing module according to the invention before assembly without a tube or main housing in cross section analogous to the section line VI-VI in FIG. 4,

6 in a cross-sectional view corresponding to FIG

Line Vl-Vl in Figure 4, the bearing module after assembly in the main housing of the steering gear,

FIG. 7 shows an end view of a blank for a steel spring ring according to the invention,

FIG. 8 shows a sectional view along the line VIII-VIII in FIG. 7 after the blank has been formed in accordance with FIG. 8a,

FIG. 8a shows a perspective illustration of the steel spring ring according to FIG. 8,

FIG. 9 shows a force-displacement diagram for O-rings (70

Shore A) as spring washer elements

FIG. 10 shows a further embodiment of the bearing module or steering gear according to the invention in a section-wise, axial longitudinal section,

FIG. 11 shows a sectional view along line XI-XI in FIG. 10,

FIG. 12 shows an enlarged illustration of detail XII in FIG. 10,

FIG. 13 shows a longitudinal view in the radial direction of the outer casing of the pressure ring with a complementary pressure piece with the gear housing cut open, Figure 14-18 each in an axial longitudinal view of the respective state of the steering gear housing after individual assembly steps

According to FIG. 1, the steering gear has a tubular rack main housing 1, on the outer jacket of which a tubular pinion housing 2 is also attached obliquely or transversely. This is closed at one end with a bearing ring 3 like a lid. The wall of the main housing 1 is penetrated by holes 10, to which connection pieces for hydraulic oil can be attached in the case of hydraulic steering. However, the invention can also be used for electric steering. The other end of the pinion housing 2 is expanded radially outwards to form a flange 4 for further connection purposes (for example connection or installation of a hydraulic valve).

According to FIG. 2, fin-like fastening brackets 5 are connected to the outer casing of the main housing 1, through which sleeves 6 provide a passage for fastening means transversely to the axial or longitudinal direction. A rack 11 penetrates within the main housing 1 at the left end of the drawing the bearing module 7 according to the invention, which is designed as a fully assembled combination part, in the central region where a molding is applied (cf. DE patent application 101 01 717.0), a seal holder 8 and in the right end area in FIG. 2, a toothed / piston rod guide bearing 9. The respective end faces of the bearing module 7 and the guide bearing 9 facing the main housing ends are designed or used as stop faces 12 (so-called lockstop) in order to control the steering stroke in connection with the Limit tie rods 13. The main housing end regions are designed with radial widenings 13a in order to form a stop shoulder 13b for the axial insertion limitation of the bearing module 7 and the guide bearing 9. Furthermore, the ends are covered in a manner known per se with bellows 14 through which the tie rods 13 are guided. Within the pinion housing 2, a drive pinion 15 extends obliquely or transversely to the toothed piston rod 11 (and to the plane of the drawing) and engages with the toothing region 16 of the toothed / piston rod 11. According to FIG. 4, the bearing module 7 is designed with a pressure ring 71, which is pressed into the main housing tube 1 up to the stop shoulder 13b. For this purpose, the outer casing of the pressure ring 71 is designed with a radial extension 71a which is complementary to the shape of the stop shoulder 13b of the housing wall. On its inner circumference, the pressure ring 71 forms a receiving bore 76, in which an inner ring 72 and two circumferential spring ring elements 74 are received. The inner ring 72 serves as a guide component for the toothed rack 11 and is provided on its inner circumference with a guide bushing 75 attached to it for its sliding bearing. The two spring washers 74 inserted axially one behind the other in outer grooves 77 of the inner ring 72 are circumferentially arranged between these outer grooves 77 or the inner ring 72 on the one hand and the pressure ring 71 or the bore wall 78 on the other hand. The inner ring 72 is permanently axially fixed on the one hand by means of a locking ring 73 which is placed on a first end face of the inner ring 72. The latter is permanently fixed axially by a front edge 79 of the pressure ring 71 which is bent by means of flanges. This engages behind the locking ring 73 on its end face facing away from the inner ring 72. On the other hand, for holding the inner ring 72 axially, a holding shoulder 80 is used, which is formed on the end face of the pressure ring 71 facing the end of the main housing 1 and projects radially inward and engages behind the directly opposite end face of the inner ring 72. In order to ensure the radial adjustability of the inner ring 72 necessary for the purposes of the invention, it is expedient to secure the latter with a small axial play (for example 0.05 to 0.1 mm). The holding shoulder 80 of the pressure ring 71 also forms on its outside a stop surface or a fixed stop 80a for the steering stroke of the rack with a tie rod 13 attached to it via a joint 17.

As can be seen in particular from FIGS. 5 and 6, the pressure ring 71 is designed to be eccentric to the extent that the central axis 81 of the receiving bore 76 does not coincide with the central axis 82 of the external pressure ring diameter 83. In other words, the inner and outer diameters of the pressure ring 71 do not run concentrically to one another, rather there is an eccentricity between the two, the dimension e of which is between 0.2 mm and 0.6 mm, for example can be. The spring ring 74 resting against the bore wall 78 of the pressure ring 71 is in the undeflected or in the relaxed initial state if, according to FIG. 5, the bearing module 7 has not yet been pressed into the steering gear main housing 1. As a result, the spring ring 74 extends with its outer and inner circumference concentrically to the central axis 81 of the pressure ring receiving bore 76 and eccentrically to the central axis 82 of the outer diameter of the pressure ring 83. The same also applies to the inner ring 72 and the guide bushing 75 fastened to its inner jacket, because this circular connection 72, 75 is centered by the spring ring or rings 74 on the receiving bore central axis 81.

According to FIG. 6, the bearing module 7 is mounted in the main housing 1 of the steering gear, the rack 11 being pressed against the drive pinion 15 by the bearing module 7. The assembly is facilitated by an orientation groove 84 which is formed in the outer circumference of the pressure ring 71. According to the example shown, it is diametrically opposite that part of the pressure ring wall which has the greatest wall thickness. The orientation groove 84 runs parallel to the central axes 81, 82 (ie perpendicular to the drawing planes of FIGS. 5 and 6). Complementary to the orientation groove 84 is formed on the inner wall of the main tube 1, for example by stamping, a radially inwardly projecting orientation cam 18 which also runs axially parallel. Furthermore, in the assembled state according to FIG. 6, the inner ring 72, together with the guide bush 75 encompassed by it, is now centered by the guided toothed / piston rod 11 on the central axis 82 of the pressure ring outer diameter 83, which in turn is concentric in and with the outer or inner circumference of the tubular main housing 1 runs. Due to the rigid, unchangeable eccentricity of the receiving bore 76 of the pressure ring 71, there is a complementary, eccentric deformation of the spring ring or rings 74 such that the point with the smallest spring ring thickness 85 bears directly against the point with the greatest wall thickness 88 of the pressure ring 71.

From this eccentric deflection of the one or more spring washers 74 there is the further effect that a spring force arises that most starts from the point with the minimum spring ring thickness 85 and is directed to the diametrically opposite point 86 with the maximum spring ring thickness. Since both the inner ring 72 with guide bush 75 and the toothed rack 11 are encompassed by the spring ring or rings 74 in the assembled state, the latter is gripped by the spring force mentioned and also pressed in the direction of the maximum spring ring thickness 86 and thus on the drive pinion 15.

The comparison of FIG. 5 with FIG. 6 shows that the assembly of the inner ring 72 and guide bushing 75 and thus the guide passage 87 delimited by them is radially displaced in the direction of the location by mounting the bearing module 7 in the steering gear main housing 1 with the maximum pressure ring thickness 88. This takes place when the bearing module 7 is pressed into the main housing 1, the toothed / piston rod 11 and drive pinion 15 having been expediently already mounted beforehand and brought into engagement with one another. For pressing in, the self-contained bearing module 7 is pushed over the toothed / piston rod 11 protruding from the main housing 1 and then into the main housing 1. This is only possible if the orientation cam 18 on the inner wall of the housing and the orientation groove 84 on the outer circumference of the pressure ring 71 move into one another. The orientation groove 84 is positioned in the circumferential direction in such a way that when this enables the bearing module 7 to be inserted, the point with the maximum pressure ring thickness 88 (indirectly via spring washers 74 and composite guide ring 72, 75) on the side or the circumferential section of the toothed / piston rod for contact or comes into effect, which or which of the side or the peripheral portion with the toothing 16 are diametrically and optionally axially offset. With further pressing of the bearing module 7, which is best done with a specially made, preferably machine tool, the guide part consisting of the inner ring 72 and the guide bush 75 increasingly moves to the spot with the maximum pressure ring thickness 88, because the space and installation conditions within the Main tube for the toothed / piston rod 11 meshing with the drive pinion 15 do not allow another path or a different evasion for the guide part 72, 75. In other words, the guide part 72, 75 is countered by the increasing pressing of the bearing module 7 up to the stop shoulder 13b the spring force and thus prestressed by the spring washers 74 is radially displaced to the point with the maximum pressure ring thickness 88. The offset corresponds approximately to the eccentricity measure e given above. In response to this, the point with the minimum spring ring thickness 85 results in the spring force which is directed to the side or the peripheral section of the toothed rack which is diametrically or axially offset from the toothing region 16. As a result, the toothed / piston rod 11 is pressed against the drive pinion 15, any play during steering movements being largely avoided for the toothing engagement.

The spring constant of the spring ring (s) 74 is expediently dimensioned such that a deflection force of 200-300 Newtons arises when deflected by the eccentricity measure e mentioned, which is particularly suitable for car steering systems. When the bearing module 7 is pressed in, the toothed / piston rod 11 automatically and radially or eccentrically displaces the guide part assembly 72, 75 with spring deflection or with the generation of the spring preload without the need for further adjustment steps because the toothed / piston rod 11 is in the middle Seal holder 8 and in the end guide bearing 9 is positively guided and passes through the guide passage 87 delimited by the guide part assembly 72, 75. The force with which the toothed / piston rod 11 is pressed against the drive pinion 15 is thus automatically generated without the need for further adjustment steps, the magnitude of the force being able to be influenced beforehand by the selection of the spring constant.

7, 8 and 8a, a slotted or notched steel spring washer 19i from a blank 19 is proposed, so that the pressing force "rack against drive pinion" is generated for continuous steering operation.

According to FIG. 7, a flat or flat blank 19, for example made of sheet steel, is provided for producing the steel spring washer, which was first provided with a circular ring shape, for example by stamping. Furthermore, recesses 19a are provided both from the radially outside and from the inside radially Recesses 19b made. Both can also be created by punching. Seen in the circumferential direction 19c of the spring ring, the outer and inner recesses 19a, 19b alternate with one another.

According to FIG. 8, the inner and outer edges of the circular blank 19, which form inner and outer connecting webs 19d and 19e, have been bent toward one another, specifically using the aforementioned connecting webs 19d, 19e, so that an inner connecting web 19d and an outer connecting web 19e are partially in relation to one another opposite (as can be seen from Figure 8a). This results in — seen in the sectional view in FIG. 8 — C profiles which, according to FIG. 8a, form individual C spring members 19f with respective openings 19g. Depending on the radial load, the latter can move up and down in a jaw-like fashion to or from the central axis 19h of the steel spring washer 19i.

As illustrated above all in FIG. 8a, the steel spring ring 19i consists of a plurality of individual C spring members 19f, which are connected to one another alternately via inner connecting webs 19d and outer connecting webs 19e. These form a spring ring chain around the central axis 19h. By elastically reversibly compressing the individual C spring members 19f under radial loading, they exert a radial force on an object (for example, rack 11 above) which is encompassed by the spring ring. The effect of the force is due to the mechanical tension under which the C-spring elements stand.

According to FIG. 8a, the respective connecting webs 19d, 19e start from the opposite ends of the individual C spring members 19f. The ends, which delimit the spring member openings 19g, lie opposite one another in the spring member circumferential direction 19k about the respective spring member central axis 191. In this regard, the inner connecting webs 19d, which each start from first ends of the C-spring links 19f, have mutually identical or congruent angular positions. The same applies to the outer connecting webs 19e, which each start from the opposite second ends of the C-spring links 19f. If elastomer rings (O-rings) known per se are used, according to the diagram in FIG. 9, with a deflection path between 0.2 mm and 0.4 mm (which corresponds to the range of the eccentricity measure e given above), the spring force specified above of 200- 300 Newtons.

As mentioned above, by pressing in the entire bearing module 7, the inner ring 72 is displaced radially by the amount of the previously applied eccentricity e of, for example, 0.3 mm (cf. FIGS. 5 and 6) and thereby generates the spring characteristic of the spring ring element or elements 74 a pressure force (rack against pinion) of 200 - 300 Newtons. This results in the safety clearance 89 shown in FIG. 10 of, for example, 0.2 mm. With an interference force of more than 300 Newtons, this can have an effect on the rack play, that is, the rack 11 lifts off the pinion 15 by this amount.

In order to further reduce this toothed rack play, the pressure ring 71 is designed according to FIG. 10 with an opening 90 (cf. also FIG. 13), in which an additional complementary pressure piece 91, for example made of plastic, is used. This is pressed by the inner wall of the main housing 1 via its axially parallel sides 92 into contact with the inner ring 72. The common contact surfaces 93 of the pressure piece 91 and the inner ring 72 are wedge-like, for example at an angle of 6 °, relative to the (parallel) central axes 81, 82. A further pressure piece side section 95 adjoins the aforementioned 6 ° contact surface 93 of the pressure piece 91 via an obtuse angle 94 and bears against one of the spring ring elements 74. This side section 95 of the pressure piece 91 also has a wedge-like inclination of, for example, 30 ° with respect to the central axes 81, 82.

Furthermore, according to FIG. 10 (see also, for example, FIG. 19), a beading 96 is provided in the wall of the main housing 1 from outside, which only extends over a partial circumference of the tubular main housing 1. In cooperation with the stop shoulder 13b or the radial widening 13a, the bead formation 96 results in an axial fixing of the bearing module 7. As can be seen from FIG. 11, the pressure piece 91 is curved or curved in accordance with the circumference of the main housing 1, the concave side resting on the inner ring 72.

In the enlarged longitudinal section according to FIG. 12, the pressure piece 91, seen in the assembly insertion direction 99 (see FIGS. 14-19), has front and rear sides 97, 98 which form a right angle with the axially parallel side 92. For the rest, reference can be made to the comments on FIG. 10.

According to FIG. 13, the pressure piece 91 is inserted into the contour of the opening 90 of the pressure ring 71 already mentioned, with two orientation tabs 100 projecting rearward, as seen in the mounting insertion direction 99. The underside of the latter are provided with the 30 ° side sections 95 which are assigned to one of the spring ring elements 74. As an alternative or in addition to the orientation tabs 100, other geometrical orientation means can also be used to ensure that the pressure piece 91 is used in a functionally correct manner, for example indentations at the edge or recesses in the inner region of the pressure piece 91 that the pressure piece cannot be inserted incorrectly into the opening 90 of the pressure ring due to the orientation means.

To further illustrate the mode of operation, individual assembly steps are described below, which are necessary for the use of the bearing module according to the invention with a supplementary / complementary pressure piece 91 in the steering gear main housing 1.

According to FIG. 14, the pinion 15 and the rack 11 are already installed in the main housing 1. The bearing module 7 with the pressure ring 71, inner ring 72 etc. is pushed onto the rack 11 in the insertion direction 99. Before being immersed in the main housing 1, the pressure piece 91 is inserted into the opening 90 with a self-checking shape. According to FIG. 15, the bearing module 7 is preferably advanced by hand so that the above-mentioned orientation groove 84 in the outer jacket of the pressure ring 71 engages with the orientation cam 18 on the inner wall of the main housing 1.

According to FIG. 16, the further displacement of the bearing module 7 with the pressure piece 91 inserted is expediently supported by a mechanical, power-operated tappet 101. After leaving the radial expansion 13a of the main housing 1, the main housing 1 forms an internal press-in passage 102 with respect to the outer circumference of the bearing module 7. This is dimensioned such that the spring ring elements 74 are loaded on one side and, due to the eccentricity e described above, the radial displacement of the inner ring 72 takes place. This results in the spring preload for pressing the rack 11 against the pinion 15.

17, the complementary pressure piece 91 also enters the press-in passage 102 with increasing displacement. In the process, it rubs against the inner wall of the main housing 1 after the radial expansion 13a, so that it moves rearward relative to the inner ring 72 against the insertion direction 99 , This causes the 6 ° contact surfaces 93 of the pressure piece 91 and inner ring 72 to slide against one another. As a result of the displacement of the pressure piece 91 to the rear, the 30 ° side section 95 of the pressure piece 91 comes into contact with the spring element 74 in the insertion direction 99. In response to the corresponding pressure, the ring spring element 74 generates a corresponding counterforce on the pressure piece 91 over its 30 ° -Side section 95. The pressure piece 91 is held by a balance of forces. This process continues until the pressure ring 71 with its radial extension 71a abuts the inner stop shoulder 13b of the housing 1 corresponding to the radial housing expansion 13a.

The pressure of the pressure piece 91 on the spring ring element 74 generates a low counter-spring force, which holds the pressure piece 91 in connection with the 6 ° ramp of the contact surfaces 93 in a play-free block position. The 6 ° inclination angle of the contact surfaces 93 lies in the area of self-locking, so that even with strong ones Bumps no noticeable rack play is effective. Due to the aforementioned equilibrium of forces for the pressure piece 91, it is locked in the axial direction and cannot slip. Due to the 6 ° inclination of the contact surfaces 93, a frictional force arises which, in combination with the spring force, prevents slipping due to the spring ring element 74 slightly deflected by the 30 ° side section 95. Thus, with a very small securing force, which results from the deflection of the spring ring element 74 through the 30 ° side section of the pressure piece 1, the pressure piece 91 is locked in the axial direction. For this purpose, the slightly deflected spring ring element 74 generates a force component parallel to the longitudinal axis (securing force). The complementary pressure piece 91 is, as it were, locked in the opening 90 between the 6 ° contact surfaces 93 and the spring ring element 74 resting on the 30 ° side section 95. Its slight deflection by the axially displaced pressure piece 91 ensures its axial positioning and locking.

FIG. 18 illustrates the form-fitting securing of the bearing module 7 against axial displacement by means of the partial beading 96 already mentioned.

LIST OF REFERENCE NUMBERS

1 main body

2 pinion housings

3 bearing ring

4 flange

5 mounting brackets

6 sleeve

7 storage module

8 seal holders

9 rack / piston rod guide bearings

10 hole

11 rack / piston rod

12 stop surface

13 tie rod a radial expansion b stop shoulder bellows drive pinion toothing area joint orientation cam steel cut a outer recess b inner recess c spring ring circumferential direction d inner connecting web e outer connecting web f C-spring link g opening h central axis i steel spring ring k spring link circumferential direction 1 spring link central axis racks - / Housing center axis thrust ring a radial extension inner ring retaining ring spring ring element guide bush locating hole outer groove hole wall edge retaining shoulder a fixed stop center axis of the locating hole center axis of the outer diameter of the thrust ring 83 pressure ring outer diameter

84 orientation groove

85 minimum spring washer thickness

86 maximum spring ring thickness 87 guide passage

88 maximum pressure ring thickness e eccentricity measure

89 safety game

90 opening 91 pressure piece

92 axially parallel side

93 6 ° contact surfaces

94 obtuse angles

95 30 ° side section 96 beading

97 front

98 rear

99 Installation direction

100 orientation tab 101 pestle

102 press fit

Claims

claims

1. Bearing module (7) for a motor vehicle steering gear with a rack (1 1) and an engaging drive pinion (15), the bearing module (7) having at least one pressure ring (71) with a receiving bore (76), the Bore wall (78) with respect to the outer circumference (83) of the pressure ring (71) and / or an imaginary central axis (19) of the rack (11) extends eccentrically and one

Surrounds the guide passage (87) for the axial guidance of the toothed rack (11), and radial forces can be generated from the bore wall (78, 88) for the pressure of the toothed rack (11) received in the guide passage (87) on the drive pinion (15) engaging therein, characterized in that the guide passage (87) is directly delimited by one or more separately formed guide parts (72, 75), which are arranged inside the receiving bore (76), are elastically and / or resiliently supported on the bore wall (78) and thereby at least are radially adjustable by the amount and / or to compensate for the eccentricity (e) of the pressure ring (71) against the spring force.

2. Bearing module (7) according to claim 1, characterized in that the or the guide parts (72, 75) are arranged and / or formed symmetrically or concentrically with respect to an imaginary line of symmetry or center axis (81, 82).

3. Bearing module (7) according to claim 1 or 2, characterized in that at least one inner ring (72) is arranged as a guide part within the eccentric receiving bore (76) of the outer pressure ring (71) and on the bore wall (78) via one or more radially aligned, elastic pressure elements is resiliently supported.

4. Bearing module (7) according to claim 1, 2 or 3, characterized in that the resilient support or the elastic or the Pressure elements are realized by one or more radially deflectable spring ring elements (74, 19) which run parallel to the inner circumference and / or in contact with the bore wall (78) around the guide part (72, 75).

5. Bearing module (7) according to claim 4, characterized in that the one or more spring ring elements (74, 19) run between the bore wall (78) of the pressure ring (71) and the outer jacket of the guide part or parts (72, 75).

6. Bearing module (7) according to one of the preceding claims, characterized in that in the non-radially adjusted or not assembled state (Figure 5), the receiving bore (76) of the pressure ring (71), or the guide parts (72, 75), if necessary the inner ring (72) and optionally the one or more spring ring elements (74, 19) run concentrically to one another.

7. Bearing module (7) according to one of the preceding claims, characterized in that the pressure ring (71) on one or both end faces one or more, radially inwardly projecting holding shoulders or elements (79, 80) for axially holding the or the guide parts (72.75).

8. Bearing module (7) according to claim 7, characterized in that the or at least one of the holding elements (79, 80) is formed by flanging (79) or other bending radially inwards.

9. Bearing module (7) according to claim 7 or 8, characterized by a retaining ring (73, 80) gripped by the retaining shoulder or the retaining element (79, 80), by means of which the guide part (s) (72, 75) are axially stable.

10. Bearing module (7) according to one of the claims, characterized in that the guide part or parts (72, 75) are held with axial play.

11. Bearing module (7) according to one of the preceding claims, characterized in that at least one outer end face of the pressure ring (71) is designed and / or arranged as a stop surface (80a).

12. Bearing module (7) according to one of the preceding claims, characterized in that the outer jacket of the pressure ring (71) with one or more stop shoulders or ramps or other radial extensions (71a) is designed for the mounting insert in a steering gear housing ,

13. Bearing module (7) according to claim 12, characterized in that the stop shoulder or ramp is designed by a transition from a smaller to a larger outer diameter of the pressure ring (71).

14. Bearing module (7) according to one of the preceding claims, characterized in that the outer jacket of the pressure ring (71) is provided with one or more orientation projections and / or depressions (84), the complementary depressions or projections (18) one The imaginary steering gear housing (1) is assigned and positioned in the circumferential direction in such a way that with imaginary assembly (Figure 6) with the rack (1 1) and the drive pinion (15) in the housing (1) starting from the bore wall (78,88) Compressive forces are directed to the outside of the toothed rack or to the outer casing section of the toothed rack which are diametrically opposed to their teeth (16) meshing with the drive gear and possibly axially offset.

15. Bearing module according to one of the preceding claims, characterized in that the pressure ring (71) is formed from a plurality of ring-like individual parts (71, 91).

16. Bearing module according to one of the preceding claims, characterized in that the pressure ring (71) has at least one recess, Breakthrough (90) and / or interruption for the use of at least one complementary pressure piece (91), which is designed for contact from the outside to the or at least one (72) of the guide parts (72, 75).

17. Bearing module according to claim 16, characterized in that the or at least one (72) of the guide parts (72, 75) has a contact surface (93) assigned to the pressure piece (91), which is in relation to a central axis (81, 82) or axially parallel longitudinal direction or line of symmetry of the guide passage (87, 102) runs in a wedge-like manner in such a way that when the load is directed radially inward, the adjacent pressure piece (91) is automatically locked in the axial passage direction (99) on the basis of a self-locking effect.

18. Bearing module according to claim 17, characterized in that the angle of inclination of the wedge-like contact surface (93) with respect to the central axis (81, 82) or axially parallel longitudinal direction or line of symmetry of the guide passage (87, 102) is in the range of 4 to 8 degrees or, for example, 6 degrees is.

19. Bearing module according to one of claims 3 or 4 and possibly one of the other claims, characterized in that the pressure ring (71) has at least one recess, opening (90) and / or interruption for the use of at least one complementary pressure piece (91), which is designed to bear against the or at least one of the elastic pressure elements or spring elements (JA).

20. Complementary pressure piece (91) for a bearing module according to one of claims 15 to 19, characterized by a shape with two consecutive side sections over an obtuse angle (94)

(93,95).

21. Complementary pressure piece (91) according to claim 20, characterized in that the obtuse angle (94) is in the range from 120 to 160 degrees or is, for example, 144 degrees.

22. Complementary pressure piece (91) according to claim 20 or 21, characterized in that the two side sections (93, 95) each form an acute angle with a side (92) opposite them together.

23. Complementary pressure piece (91) according to claim 22, characterized in that the acute angles are between 15 and 45 degrees or between 4 and 8 degrees.

24. Complementary pressure piece (91) according to one of claims 22 or 23, characterized by a cuboid or cube-like basic shape, the side (92) opposite the two side sections (93, 95) having a front and / or rear side (97 , 98) each encloses a right angle.

25. Complementary pressure piece (91) according to any one of claims 22 to 24, characterized by orientation or alignment projections (100) or recesses as assembly aids.

26. Complementary pressure piece (91) according to claim 25, characterized in that the side (92) opposite the two side sections (93, 95) has one or more orientation or alignment projections or tabs (100) and / or orientation or

Alignment indentations and / or recesses, which are in a common with the opposite side (92) or

Extend circumferential surface.

27. Complementary pressure piece (91) according to one of the preceding claims, characterized in that it is a plastic injection molded part.

28. Motor vehicle steering gear with a bearing module (7) mounted therein according to one of the preceding claims, which bearing module (7) with its guide passage (87) engages with a drive pinion (15) rack (11) within a gear housing ( 1), characterized in that the guide part (s) (72, 75) of the bearing module (7) through the rack (11) against spring force radially and eccentrically with respect to the central axis (81) of the receiving bore (76) of the guide passage (87) surrounding bearing module pressure ring (71) are offset.

29. Steering gear according to claim 28, characterized in that the measure of the eccentricity (e) between the central axis (82) of the rack (11) and / or the housing (1) and / or one of the or the guide parts (72,75 ) formed inner contour on the one hand and the

The central axis (81) of the pressure ring receiving bore (76) on the other hand is between approximately 0.1 to 0.8 mm.

30. Steering gear according to claim 28 or 29, characterized in that the spring forces by means of one or more, radially deflectable

Spring ring elements (74, 19) are realized which are pressed together radially and eccentrically via a section (85) which bears against a peripheral section of the pressure ring (71) with an eccentrically increased wall thickness (88).

31. Steering gear according to one of the preceding claims, characterized in that the spring forces are realized by means of one or more, radially deflectable spring ring elements (74, 19) which are pressed together radially and eccentrically via an arc (85), as seen in the radial direction congruent with the outside of the rack or the

The outer casing section of the rack lies and / or runs parallel to the latter, which is opposite the teeth (16) of the rack (11) meshing with the drive pinion (15) diametrically and optionally axially offset.

32. Steering gear according to claim 30 or 31, wherein the one or more spring ring elements (19) have an annular base body, the shape of which is elastically changeable in the radial direction, characterized in that the base body is distributed over its circumference

Notches, slots and / or other recesses is provided, the longitudinal, central or symmetry axes are aligned substantially radially.

33. Steering gear according to claim 32, characterized in that the slots, notches or other depressions are alternately attached starting from the inner and the outer circumference.

34. steering gear according to claim 32 or 33, characterized by a manufacture of the spring ring elements made of sheet steel.

35. Steering gear according to one of the preceding claims, with a bearing module (7) according to claim 14, characterized in that the housing inner wall, preferably in the front end region, one or more recesses or elevations (18) complementary to the one or more orientation elevations and / or depressions of the pressure ring outer casing (84) with a positioning in the circumferential direction such that when the orientation elevations or depressions (18, 84) are pushed into one another on both sides, they start at the bore wall (78, 88)

Compressive forces are directed to the outside of the toothed rack or to the outer casing section of the toothed rack which are diametrically opposite the teeth (16) of the toothed rack (11) which mesh with the drive gear (15).

36. Steering gear according to one of the preceding claims, characterized in that the bearing module (7) is arranged in an end region of the transmission housing such that the pressure ring (71) has a stop face (12, 80a) with an end face facing the housing end region. for a steering stroke limitation, for example with respect to an adjacent tie rod joint (17).

37. Steering gear according to one of the preceding claims, characterized in that in the radially adjusted or mounted

State (Figure 6) the receiving bore (76) of the pressure ring (71) with respect to the central axis (82) of the rack (1 1), the gear housing, or the guide parts (72, 75), optionally the inner ring (72) and / or optionally the one or more spring ring elements (74, 19) is eccentric or extends.

38. Steering gear according to one of the preceding claims, with a bearing module (7) according to claim 15, wherein one of the individual parts (71, 91) of the pressure ring (consists of a complementary pressure piece (91) according to one of claims 20 to 26, characterized that one of the two side sections (93, 95) of the pressing piece (91), which are lined up at an obtuse angle, rests on or on one of the spring elements (74) and / or the other on or on one of the guide parts (72, 75).

39. Steering gear according to claim 38, characterized in that the common contact surfaces (93.95) of the complementary pressure piece (91) on the one hand and the or the guide parts (72,75) and the or the spring elements (74) on the other hand wedge-like oblique with respect to The central axis (81, 82) of the guide passage (87, 102) and / or the rack (1 1) run.

40. Steering gear according to claim 38 or 39, with a complementary pressure piece (91) according to claim 22, characterized in that the two side sections (93.95) opposite side (92) of the complementary pressure piece on the inner wall of the transmission

Main housing (1) rubs.

41. Spring ring element (74) for a bearing module (7) according to claim 4 or 5 and optionally one of the other claims, characterized by an O-like formation with elastomer and / or another elastic plastic.

42. spring ring element (19i) for a bearing module (7) according to claim 4 or 5 and optionally one of the other claims, characterized by a design with a helical spring with a helically wound base body which is closed at its ends to form a ring.

43. spring ring element (19i) for a bearing module (7) according to claim 4 or 5 and possibly one of the other claims, characterized by a design with a plurality of elastic spring members (19f), which is ring-shaped and arranged in a ring to form the spring ring element (19i) are connected.

44. spring ring element (19i) according to claim 43, characterized in that its ring plane to that of the spring members (19f) extends obliquely or perpendicularly.

45. Spring washer element (19i) according to claim 43 or 44, characterized in that at least one of the spring members (19f) has a C-like shape or the shape of an open ring.

46. Spring washer element (19i) according to claim 45, characterized in that the ring openings (19g) of the spring members (19f) at least partially point in the same and / or directions parallel to the central axis (19h) of the spring washer element (19i).

47. Spring ring element (19i) according to one of the preceding claims, characterized in that at least one of the spring members (19f) is connected to one or two adjacent spring members (19f) via a connecting web (19d, 19e).

48. Spring ring element (19i) according to claim 45 and 47, characterized in that the connecting web (19d, 19e) extends from the end (19g) delimiting the end of the C-type spring member (19f) to the adjacent spring member (19f).

49. Spring washer element (19i) according to claim 48, characterized in that in the case of a plurality of lined-up or all C-spring members (19f) in the circumferential direction (19k) around their central axes (19h), a first and a second end, which face the opening, lie opposite one another (19g) limit, and the connecting webs (19d, 19e) extend in the circumferential direction around the central axis (19h) of the spring ring element (19i) alternately between two first and two second ends of respectively adjacent C-spring members (19i).

50. spring ring element (19i) according to claim 49, characterized in that in the circumferential direction (19c) around the respective spring member central axis (19h), the first and second ends each have the same first and same second angular positions.

51. Spring washer element (19i) according to claim 49 or 50, characterized by a manufacture from a flat and / or flat blank (19) with the basic shape of a circular band, wherein alternately from the outside radially and inside from slot or notch-like recesses (19a, 19b ) are made.

52. Spring washer element (19i) according to claim 51, characterized in that the radially inner and outer edges of the circular ban blank are bent towards one another.

53. spring ring element (19i) according to any one of the preceding claims, characterized by a production with steel and / or another metal.