Progressive diverter, sawtooth component, and method of manufacture

Abstract

A sawtooth component (10) for a progressive steering system includes first and second inclined sawtooth ramps (14, 16). The first and second inclined sawtooth ramps (14, 16) include a plurality of sawtooths (20, 50), each sawtooth having a first tooth face angle and a second tooth face angle relative to a central plane (48) extending perpendicular to a longitudinal direction (34) of the sawtooth component (10). For at least 50% of the plurality of sawtooths (20, 50), the first tooth face angle has a unique first angle value, and the second tooth face angle has a unique second angle value, the first angle value corresponding to a mirror image of the second angle value at the central plane (48). The invention also includes a progressive steering system, a method of manufacturing a sawtooth component, and a method of manufacturing a steering system.

Description

[0001] This invention relates generally to the technical field of vehicle steering systems, and particularly to the field of progressive steering systems and / or rack and pinion steering systems.

[0002] Progressive steering systems are known in a wide variety of configurations. For example, WO 2006 / 079492A1 illustrates various embodiments of a progressive steering gear. According to one embodiment that has proven particularly advantageous in practice, the progressive steering gear has three inclined racks and three associated spur gears located in different planes. In a steering position on one side of the center position, the center spur gear engages the center rack, while in a steering position on the other side of the center position, the two outer spur gears engage the two outer racks.

[0003] As stated above, the embodiments according to WO 2006 / 079492 A1 have proven highly advantageous in practice. However, during extensive work and testing, further improvements have been discovered, particularly concerning, but not limited to, a particularly harmonious driving experience and / or cost-effective manufacturing. These improvements are the technical solutions described in this document.

[0004] This invention is defined by the independent claims. The dependent claims relate to optional features of some embodiments of the invention.

[0005] A first aspect of the invention relates to a serrated component for a progressive steering gear (or steering transmission), comprising first and second inclined serrated ramps having a plurality of serrations, each serration having a first tooth face angle and a second tooth face angle relative to a central plane extending longitudinally perpendicular to the serrated component. For at least 50% of the serrations, the first tooth face angle has a unique first angle value, and the second tooth face angle has a unique second angle value, wherein the first angle value corresponds to a mirror image of the second angle value on the central plane.

[0006] It has been found that using serrated teeth according to the invention instead of the teeth commonly used in rack and pinion steering systems offers considerable advantages. The uniform tooth profile angle, symmetrical with respect to the center plane, results in a particularly harmonious and safe steering experience and / or allows for relatively inexpensive manufacturing. These results are surprising because they contradict decades of calculations and optimizations of tooth geometry, particularly in the field of rack and pinion steering.

[0007] Another aspect of the invention relates to a progressive steering system, a method of manufacturing a serrated component, and a method of manufacturing a steering system.

[0008] Further features, advantages, and objects of the invention will become apparent from the accompanying drawings of several exemplary embodiments. In the drawings:

[0009] Figure 1This is a side view of the serrated component and the pinion component according to a first exemplary embodiment of the present invention.

[0010] Figure 2 This is a perspective view of components of a progressive steering system according to a second exemplary embodiment of the present invention, which is related to... Figure 1 The first exemplary embodiment shown is only slightly different.

[0011] Figure 3 These are enlarged views of the sawtooth geometry in the first and second example embodiments.

[0012] Figure 4 The third example embodiment, which has a steeper tooth angle, is similar to... Figure 1 Side view,

[0013] Figure 5 In the fourth example embodiment, similar to Figure 1 A side view showing the serrated component without a central serration.

[0014] Figure 6 This is an exploded view of the pinion component and related components in another example embodiment.

[0015] Figure 7 This is a schematic diagram showing the design of the pinion element.

[0016] Figure 8 and Figure 9A These are enlarged side views illustrating the scrolling behavior in the first and second example embodiments, respectively.

[0017] Figure 9B It is similar to the comparative example Figure 9A Enlarged side view,

[0018] Figure 10A These are schematic side views of the first and second exemplary embodiments of the present invention.

[0019] Figure 10B This is a schematic side view of the rack in the comparative example, and its scale is similar to... Figure 10A Similarity in

[0020] Figure 11 This is a perspective view of a steering gear according to another exemplary embodiment of the present invention, and

[0021] Figure 12 Is it like this? Figure 11 The perspective view shown only shows the serrated part and the pinion part.

[0022] The progressive steering system according to the embodiment illustrated in the accompanying drawings includes a sawtooth component 10 and a pinion component 12. The sawtooth component 10 includes first, second, and third sawtooth ramps 14, 16, and 18, arranged in three planes, according to... Figure 1 Arranged sequentially on component 10 in the lateral viewing direction. The first sawtooth ramp 14 is... Figure 1 Visible on the left. The second sawtooth slope 16 is... Figure 1 Most of the right side is visible, except for the central serration 20 ( Figure 2 The first sawtooth ramp 14 and the second sawtooth ramp 16 overlap at the central sawtooth. The third sawtooth ramp 18... Figure 2 The middle part is visible, but... Figure 1 The middle is completely obscured by the first sawtooth slope 14, in Figure 1 In the side view, the first sawtooth ramp 14 has the same profile as the third sawtooth ramp 18 and is located exactly in front of the third sawtooth ramp 18.

[0023] Although Figure 1 and Figure 2 The example embodiment shown includes a central sawtooth 20 common to all three sawtooth ramps 14, 16, 18, but embodiments in which the second sawtooth ramp 16 does not overlap with the first and third sawtooth ramps 14, 18, and embodiments in which the overlap extends over several central sawtooths (e.g., two or three sawtooths) are also conceivable.

[0024] In this example embodiment, the serrated ramps 14, 16, and 18 are integrally formed with the base 22 having sides 24 and a lower support segment 26. The support segment 26 may have, for example, a rectangular or dovetail cross-section. Figure 2 In the illustrated example embodiment, the bracket segment 26 is guided and pressed against the pinion component 12 by a spring-loaded pressure element 28. For example, the pressure element 28 may provide a spring travel of at least 0.1 mm or at least 0.2 mm. The steering gear is designed such that the serrated component 10 is adapted to move relative to the pinion component 12 by this spring travel. The serrated component 10 has connecting means—e.g., a thread on each side—for connecting to respective couplings of the steering tie rod; Figure 2 An example of this connector 30 is shown.

[0025] In some embodiments, the serrated member 10 has no further guiding means provided in the steering gear housing (not shown), except for the guidance provided by the steering tie rod, pressure element 28, and pinion member 12. However, in other exemplary embodiments, the side portion 24 is additionally used to guide the serrated member 10 in the steering gear housing. Such a steering gear with the serrated member 10 guided by the side portion 24 is particularly stable.

[0026] In the exemplary embodiment described herein, the lower side of the support segment 26—and therefore the lower side of the base 22—forms a flat base surface 32 extending parallel to the longitudinal direction 34 of the serrated member 10. Thus, both the longitudinal direction 34 and the base surface 32 extend along the direction in which the serrated member 10 moves back and forth during steering movements.

[0027] The pinion component 12, corresponding to the sawtooth component 10 with its sawtooth ramps 14, 16, and 18 arranged on three planes, has first, second, and third pinion elements 36, 38, and 40 located on the same three planes. The three pinion elements 36, 38, and 40 are rigidly arranged relative to each other and rotatably fixed to the steering shaft end member 42, which in turn is supported in the steering shaft bearing 44. The steering shaft end member 42, together with the pinion component 12 thereon, is connected to the steering wheel (not shown) in a known manner via several portions of the steering shaft and / or steering column (not shown), such that steering movements cause a corresponding rotation of the pinion component 12. Here, the steering shaft end member 42 and the three pinion elements 36, 38, and 40 all rotate about a common axis of rotation 46.

[0028] In the example embodiment described herein, the first pinion element 36 has a... Figure 1 The first pinion element 36 precisely covers the third pinion element 40 in the side view, sharing the same profile. The second pinion element 38 is formed to be approximately or precisely mirror-symmetrical with respect to the first pinion element 36 and the third pinion element 40. Furthermore, in the example embodiment described herein, the first pinion element 36 is the same thickness as the third pinion element 40, but only half the thickness of the second pinion element 38. Correspondingly, the first serrated ramp 14 is the same thickness as the third serrated ramp 18, but only half the thickness of the second serrated ramp 16.

[0029] The first pinion element 36 is adapted to engage with the first sawtooth ramp 14 in a steering position, in which, from the driver's perspective, the steering wheel rotates clockwise relative to a center position—for example, as... Figure 2 The situation is as follows. When the steering wheel is then turned counterclockwise, the serrated part 10 moves along... Figure 2 The direction indicated is shifted to the left until the first serrated element 26 disengages from the first serrated ramp 14 and rotates freely in the empty space to the right of the first serrated ramp 14. This movement of the serrated component 10 in its longitudinal direction 34 is converted into a corresponding steering motion of the vehicle wheel; the direction of the steering motion (i.e. whether the wheel turns right or left in the direction of travel) depends on the installation position of the steering gear.

[0030] The third pinion element 40 and the third sawtooth ramp 18 operate in the same way as the first pinion element 36 and the first sawtooth ramp 14. On the other hand, the second pinion element 38... Figure 2 The steering wheel can rotate freely from the position shown, and when it is turned counterclockwise from that position, it engages with the second serrated ramp 16 from approximately the middle position of the steering wheel, that is, first with the middle serrated ramp 20, and then with... Figure 2 The serrated joint is shown further to the right in the middle.

[0031] The sawtooth ramps 14, 16, and 18 are each inclined, with the second sawtooth ramp 16 in the opposite direction to the first and third sawtooth ramps 14 and 18. A central plane 48 is arranged perpendicular to the base plane 32 and the longitudinal direction 34. In the embodiments described herein, the central plane 48 forms a plane of symmetry with respect to the overall inclination of the sawtooth ramps 14, 16, and 18. In some embodiments, the central plane 48 represents a precise plane of symmetry. However, embodiments in which the sawtooth ramps 14, 16, and 18 are not perfectly mirror-symmetric with respect to each other, and therefore the central plane 48 is only approximately a plane of symmetry. In some embodiments, a central sawtooth 20 is provided, and the central plane 48 extends through the tip of the central sawtooth 20. Furthermore, in some embodiments, when the steering gear is in the center position, the central plane 48 extends through the axis of rotation 46 of the pinion assembly 12.

[0032] In addition to the central sawtooth 20, each of the three sawtooth ramps 14, 16, and 18 includes multiple additional sawtooths, some of which are indicated by reference numeral 50 in the figures. For example, in addition to the central sawtooth 20, each of the three sawtooth ramps 14, 16, and 18 may include approximately ten additional sawtooths 50, typically between seven and thirteen additional sawtooths 50. Figure 3 As shown, each sawtooth 20, 50 has a first tooth surface 52 and a second tooth surface 54 that are approximately straight, with a rounded tip 56 formed between the first tooth surface 52 and the second tooth surface 54. Rounded valleys, or tooth bases 58, are formed between the first tooth surface 52 of the first sawtooth 20, 50 and the adjacent second tooth surface 54 of the adjacent second sawtooth 20, 50, respectively. Sawtooth bases 60, 62 extend between the two tooth bases 58 of the sawtooth 20, 50, respectively. In the case of the central sawtooth 20, the straight first and second tooth surfaces 52, 54 have equal lengths, and the sawtooth base 60 extends horizontally, i.e., parallel to the base surface 32 and the longitudinal direction 34. In the case of the sawtooth 50, which is different from the central sawtooth 20, the straight first and second tooth surfaces 52, 54 have different lengths, depending on the slope of the sawtooth base 62 relative to the base surface 32 and the longitudinal direction 34.

[0033] For example, the average inclined plane 64 over the longitudinal range of sawtooth slopes 14, 16, and 18, such as Figure 1 As shown for the sawtooth ramp 16, it can have an angle of approximately 15° relative to the base plane 32 and the longitudinal direction 34, or more generally an angle between 8° and 25°, or an angle between 10° and 20°. The angle of the inclined plane 64 corresponds to the average angle of the associated sawtooth base 62. However, local variations may exist because in many embodiments, the sawtooth ramps 14, 16, 18 are not linearly inclined, but include local corrections. These corrections can be used, for example, to compensate for progressive and / or gimbal errors in the running gear.

[0034] Each first tooth surface 52 of the serrations 20, 50 forms a first tooth surface angle relative to the central plane 48, and each second tooth surface 54 forms a second tooth surface angle relative to the central plane 48. An important feature of the serrations 20, 50 provided according to the invention is that, at least for the majority of the total number of serrations 20, 50, all first tooth surface angles have a unique first angle value +α, and all second tooth surface angles have a unique second angle value -α corresponding to the mirror image of the first angle value +α at the central plane 48. For example, in Figure 1 In the example embodiment shown, for each of the serrations 20 and 50 shown, the first angle value is +33° and the second angle value is correspondingly -33°, each with an allowable deviation of 10%, 5%, or 2%.

[0035] The property that the first and second tooth surface angles have angle values ​​of +α and -α, respectively, applies in various embodiments to at least 50% of the serrations 20, 50, or at least 70% of the serrations 20, 50, or at least 80% of the serrations 20, 50, or at least 90% of the serrations 20, 50, or all of the serrations 20, 50. Furthermore, some embodiments are provided in which the percentage refers only to those serrations 50 having a corresponding tooth base 62 inclined relative to the base plane 32 and the longitudinal direction 34. In other words, in these embodiments, the central serration 20 and any other serrations having a tooth base parallel to the base plane 32 are not considered in the percentage calculation.

[0036] The first and second angle values ​​can be chosen differently in different embodiments, but they have the same absolute values ​​for each embodiment. For example, Figure 4An example embodiment with steeper sawtooth surfaces 52, 54 is shown, wherein for each sawtooth 20, 50 shown, a first angle value is +25° and a second angle value is -25°, with a permissible deviation of 10%, 5%, or 2% in each case. An advantage of this embodiment is that a larger radius of curvature can be selected for the tips 56 and the bases 58 of the sawtooth 20, 50. It should be understood that in further embodiments, additional first and second angle values ​​are possible, for example, ±25°±5% or 30°±10% or 30°±5% or 33°±5% or 35°±10% or 35°±5%.

[0037] Pinion elements 36, 38, and 40 also have serrations, some of which are indicated by reference numeral 70 in the figures. The serrations 70 are arranged and shaped such that they engage with the serrations 20 and 50 of the serration ramps 14, 16, and 18, providing harmonious rolling motion. For example, the serrations 70 may have curved sides in the sense of involute or cycloidal tooth profiles. This results in… Figure 1 The first rolling curve 72 at the first sawtooth slope 14 shown on the left side of the middle, in Figure 1 The second rolling curve 74 at the second sawtooth ramp 16 shown on the right, and the corresponding third and fourth rolling curves 76 and 78 at the first and second pinion elements 36 and 38, respectively. On average over the length of the first and second sawtooth ramps 14 and 16, the paths of the first and second rolling curves 72 and 74 follow the inclination of the respective sawtooth ramps 14 and 16, as shown, for example, by the inclined plane 64.

[0038] In the embodiments described herein, the pressure element 28 is spring-loaded and provides a relatively large spring travel, for example, 0.1 mm or 0.2 mm. Therefore, there is a margin (or backlash) for significant manufacturing tolerances and / or deliberate deviations to optimize steering performance.

[0039] As already mentioned, embodiments in which the serrated component 10 does not have any central serrations 20 are also envisioned. Figure 5 A corresponding example embodiment is shown. Here, the first and second sawtooth ramps 14 and 16 terminate at the left and right sides of the central plane 48, respectively, and sawtooth 50 does not represent the central sawtooth 20 because it has an inclined sawtooth base 62. Instead, the pinion component 12 has a central sawtooth 80 formed in all three pinion elements 36, 38, and 40, and is located at the center of the steering gear, as shown. Figure 5 As shown, the central serration 80 extends symmetrically with respect to the central plane 48 and engages between the two serrations 50 on the left and right sides of the central plane 48.

[0040] exist Figure 5In the example embodiment shown, the serrations 50 adjacent to the left side of the central plane 48 are formed only in the first serration ramp 14 (and in...). Figure 5 (In the third sawtooth slope 18 which is not visible in the middle). Therefore, the sawtooth 50 adjacent to the right side of the central plane 48 is only formed in the second sawtooth slope 16. However, it is also possible to arrange an embodiment in which two of the above-mentioned sawtooth 50 are formed on all three sawtooth slopes 14, 16, 18, such that the sawtooth slopes 14, 16, 18 overlap in the region of the two sawtooth 50.

[0041] Figure 6 An exploded view of the pinion assembly 12 shows the use of a steering shaft end member 42 with a non-circular transverse cross section, on which three pinion elements 36, 38, and 40 are pressed and thus held at a desired angular position relative to each other. A bearing, namely a steering shaft bearing 44 and another bearing 82, is provided on each side of the assembly formed by the three pinion elements 36, 38, and 40. A spacer 84 provides a desired distance between the pinion elements 36, 38, and 40 to ensure a desired clearance between the pinion elements 36, 38, and 40 and the sawtooth ramps 14, 16, and 18, and, for example, to prevent the second pinion element 38 from rubbing laterally on one of the two sawtooth ramps 14 and 18. Figure 6 In the example embodiment shown, the spacer 84 is formed as a protrusion or thickening on the pinion elements 36, 38, 40 and the bearings 44, 82. However, embodiments in which a separate gasket or other component similar to a washer may also be provided as the spacer 84 are also possible.

[0042] Figure 7 A design example of a pinion element, such as a first pinion element 36, is shown. Each serration 70 has a serration base 86, the inclination of which approximately corresponds to the roll curve 76 at the corresponding serration 70. Figure 1 The inclination of the sawtooth base 86. The corresponding normal 88 of each sawtooth base 86 does not pass through the axis of rotation 46, but passes through the side of the axis of rotation 46.

[0043] The steering system described herein features a progressive gear ratio characteristic. At the center position of the steering system, the small distance between the pitch points of the pinion component 12's rotation axis 46 and the roll curves 72, 74, 76, 78 allows for sensitive steering movements. As steering deflection increases, the distance between the rotation axis 46 and the pitch points becomes larger, resulting in relatively small movements of the steering wheel leading to relatively large displacements of the serrated component 10. This is particularly useful for handling and parking operations.

[0044] In some embodiments, the rolling curves 72 and 74 of the serrated component 10 are straight (but inclined), and the rolling curves 76 and 78 of the pinion component 12 are helical. The steering gear ratio then varies proportionally to the angle of rotation of the pinion component 12 relative to its central position. Figure 1 However, in actual testing, it has been found advantageous to consider deviations caused, for example, by universal joint errors in the steering shaft and / or by the cumulative effects of the vehicle's running gear. Therefore, embodiments have been provided, such as those shown in the figures, in which such deviations are corrected by the non-linear rolling curves 72, 74 of the serrated component 10. Depending on the nature of the deviation to be corrected, the non-linear rolling curves 72, 74 can be mirror-symmetric or asymmetrical. The rolling curves 76, 78 of the pinion component 12 are adjusted accordingly.

[0045] The geometry of the serrated component 10 described herein differs significantly from the embodiments known from WO 2006 / 079492A1 because, at least for most of the serrations 20, 50, the angle bisector 90 of the respective serrations 20, 50 extends parallel to the central plane 48, i.e., perpendicular to the longitudinal direction 34 and / or the base plane 32. This applies at least to most of the serrations 50 whose tooth base 62 is inclined relative to the longitudinal direction 34 and / or the base plane 32. In contrast, in the embodiments known from WO 2006 / 079492 A1, the angle bisector of all teeth is perpendicular to the corresponding tangent of the roll curve at the respective tooth.

[0046] The design according to the invention enables a particularly harmonious and safe driving and steering experience. This is especially due to the fact that, for example, restoring forces from the running gear or reaction forces caused by road influences (which may occur in both directions) are uniformly fed back to the steering wheel. This... Figure 8 The center position of the turn is shown in the diagram. Figure 9A The steering position is shown in the diagram. Figure 9B As shown Figure 9A The rotational position of a comparative example with a known tooth profile, consisting of a rack and a spur gear, is shown, wherein for each tooth, the angle bisector of the tooth flank is aligned perpendicularly to the base of the tooth. Figure 9B In the comparative example shown, the reaction force is fed back to the steering wheel unevenly depending on its direction, such as... Figure 9B As shown by the horizontal arrow in the image. Conversely, according to... Figure 8 and Figure 9A The force indicated by the horizontal arrow (which is fed back to the steering wheel) is independent of the direction in which these forces act.

[0047] like Figure 8 , Figure 9A and Figure 9BAs indicated by the vertical arrows, this also applies to the reaction force portion coupled to pressure element 28. Since pressure element 28 is spring-loaded and provides a relatively large spring travel, for example, 0.2 mm, each force coupled to pressure element 28 alters the steering experience. Therefore, advantageously, the proportion of forces coupled to pressure element 28 is independent of whether these forces push the serrated component 10 to the right or left.

[0048] In summary, due to the uniform lateral load, the disturbance fluctuations between steering force and reaction force (such as restoring force) are balanced. This results in a more harmonious and safer steering and driving experience, especially with better steering feedback.

[0049] Another advantage in some embodiments of the invention is that the sawtooth geometry described herein allows for at least generally robust or even reinforced central sawtooth 20. This in Figure 10A As shown in the figure, the serration base 60 of the central serration 20 is at least as long as the serration base 62 of the side serration 50, and... Figure 10A In the example embodiments, it is even slightly longer. This increases the stability of the central sawtooth 20 under greater force, and thus represents another considerable advantage of the embodiments described herein.

[0050] Figure 10B A comparative example of a rack tooth profile is shown, in which the tooth base 94 of the center tooth 92 is significantly shorter than the tooth base 98 of the lateral tooth 96. Therefore, in this comparative example, the center tooth 92 is significantly weaker than the lateral tooth 96.

[0051] Figure 11 and Figure 12 Another exemplary embodiment of the steering gear is shown, in which two changes have been made relative to the exemplary embodiment described above. These two changes are: first, the steering gear has a motor 100, the motor having a motor shaft that is torsionally or via a transmission connected to the pinion component 12; second, serrations 50A, 50B, 50C, 70A, 70B, 70C of different sizes are provided in the serrated component 10 and the pinion component 12. The two modifications described above advantageously work together, but each modification can also be used independently. Therefore, the disclosure of this document also includes the embodiments described to date (…). Figure 1-12 The original text was modified to include only motor 100, or only saw teeth of different sizes 50A, 50B, 50C, 70A, 70B, 70C, or both.

[0052] exist Figure 10A An embodiment has been shown in which the central serration 20 has a serration base 60 that is longer than the serration base 62 of the other serrations 50. However, according to... Figure 11 and Figure 12In the serrated component 10, the serrations 50A, 50B, and 50C also have different dimensions; that is, for example, they have serration bases of different lengths and / or they have different serration heights. According to... Figure 11 and Figure 12 In this embodiment, the sawtooth 50A adjacent to the central sawtooth 20 on both sides is the largest sawtooth, and the sawtooth 50C at both ends of the sawtooth-shaped component 10 is the smallest sawtooth. As the distance from the central plane 48 increases, the size of the middle sawtooth 50B decreases uniformly or stepwise.

[0053] However, in other embodiments, the dimensional variations of the saw teeth 50A, 50B, and 50C are related to... Figure 11 and Figure 12 Conversely, as shown, the serrations 50A (and one or more central serrations 20, if any) are minimized, the serrations 50C are maximized at the ends of the serrated member 10, and the size of the intermediate serration 50B increases uniformly or stepwise with increasing distance from the central plane 48. Further dimensional variations are also provided in further embodiments. These include, but are not limited to, variations in the size of the intermediate serration 50B being greater than both the near-central serrations 50A and the outer serrations 50C, and variations in the size of the intermediate serration 50B being smaller than both the near-central serrations 50A and the outer serrations 50C.

[0054] Aside from their different dimensions, the center serration 20 and serrations 50A, 50B, 50C have the features of the exemplary embodiments described to date. In particular, also according to... Figure 11 and Figure 12 In the exemplary embodiments, all saw teeth 50A, 50B, and 50C have the same tooth profile angle or are mirrored at the central plane 48°. It should be understood that, optionally, in all embodiments described herein, a central saw tooth 20 (such as...) can be provided. Figure 1 (as shown) or two central sawtooth 20 (as shown) Figure 11 and Figure 12 (as shown) or not with sawtooth slopes 14, 16, 18 (as shown) Figure 5 (As shown) the common central sawtooth.

[0055] The serrations 70A, 70B, and 70C of the pinion elements 36, 38, and 40 are each formed as serrations 50A, 50B, and 50C corresponding to the serration slopes 14, 16, and 18, and are therefore formed in different sizes.

[0056] Figure 11 The motor 100 for power steering, further shown in the diagram, is designed, for example, as a driveless motor, with its motor shaft torsionally connected to the pinion assembly 12. Figure 11 In the exemplary embodiment shown, the motor shaft is integrated into the steering shaft and forms part of the steering shaft; Figure 11The diagram shows a steering shaft accessory 102. In other words, this portion of the steering shaft carries the rotor assembly (coils and / or permanent magnets) of the motor 100. Due to the progressive action of the steering system of the present invention, in Figure 11 No reduction gear is provided in the example embodiment shown. When the motor 100 is de-energized, it does not interfere with steering movements or with tactile feedback from the steering gear to the driver regarding road conditions.

[0057] In an alternative embodiment, the motor 100 may be connected to the steering shaft via a reduction gear. This could be, for example, a planetary gear (planetary gear train) whose central gear is formed or fixedly connected to the steering shaft, and whose ring gear is fixedly connected to the rotor of the motor 100. For example, such a planetary gear may have a reduction ratio of 1:5 to 1:20 (preferably about 1:10) such that when the motor 100 is de-energized, it does not impede or only impedes to a limited extent the feedback signal from the steering gear to the driver. In a further alternative embodiment, a bevel gear transmission or a spur gear transmission may be used instead of a planetary gear.

[0058] For example Figure 11 and Figure 12 The design shown, in which the saw teeth 50A, 50B, 50C, 70A, 70B, and 70C have different dimensions, allows for the transmission of greater torque at selected steering angles. These could be, for example, steering angles where higher steering forces typically occur and / or steering angles where the motor 100 provides particularly high steering force assistance. Alternatively or additionally, in embodiments with saw teeth 50A, 50B, 50C, 70A, 70B, and 70C of different dimensions, the tooling used to manufacture the saw tooth ramps 14, 16, 18 and / or pinion elements 36, 38, and 40 can be optimized and / or simplified. For example, in some embodiments, by forming saw teeth of different dimensions, the number of saw teeth 50A, 50B, 50C, 70A, 70B, and 70C can be reduced while maintaining the same steering quality. A smaller number of saw teeth 50A, 50B, 50C, 70A, 70B, and 70C simplifies manufacturing and requires less complex tooling.

[0059] In some embodiments, the serrated part 10 can be manufactured by forging, impact extrusion, flow stretching, or sintering. In particular, when using forging, impact extrusion, or flow stretching processes, the serrated geometry described herein has the advantage of allowing tools to be easily removed from the machined serrated part 10 due to the consistency of the tooth angles and its symmetrical orientation relative to the central plane 48. This allows for more cost-effective manufacturing.

[0060] In a further embodiment, each serrated element 36, 38, 40 is manufactured by impact extrusion, flow stretching, or stamping. Then, as... Figure 6As shown, each component 36, 38, and 40 is pressed onto the steering shaft end member 42.

[0061] Generally speaking, the present invention is not limited to the methods described above, but can utilize all methods for producing three-dimensional objects, with or without mechanical finishing. This includes, but is not limited to, for example, 3D printing or precision casting.

[0062] Due to the serrated shape according to the invention, in some embodiments, only a relatively low surface finish quality is required for the serrated teeth 20, 50 of the serrated component 10 and / or the serrated teeth 70, 80 of the pinion component 12. For example, a roughness (Ra between 3.2 μm and 25 μm) of these serrated teeth 20, 50, 70, 80 may be sufficient, referred to as "roughing". In some embodiments, the roughness Ra can be as high as 16 μm or about 16 μm. This relatively high roughness can, in particular, make some manufacturing processes (e.g., 3D printing without finishing) cheaper or more likely. Furthermore, the relatively high roughness has the advantage of allowing grease to adhere better to the tooth surfaces of the serrated teeth 20, 50, 70, 80.

[0063] The details given in the above description and shown in the accompanying drawings should not be considered as limiting the scope of the invention, but rather as examples of some embodiments of the invention. Further variations will be apparent to those skilled in the art. Therefore, the features of the above embodiments can be combined with each other to obtain further embodiments of the invention. Accordingly, the scope of the invention is not limited by the described exemplary embodiments, but by the claims and their equivalents.

[0064] List of reference numerals

[0065] 10 Serrated components

[0066] 12 pinion components

[0067] 14 First sawtooth slope

[0068] 16 Second sawtooth slope

[0069] 18 Third sawtooth slope

[0070] 20 (the center sawtooth of the sawtooth slope)

[0071] 22 Base

[0072] 24 Side

[0073] 26 Support Section

[0074] 28 Pressure Components

[0075] 30 Connecting parts

[0076] 32 base plane

[0077] 34 Vertical

[0078] 36 First pinion element

[0079] 38 Second pinion element

[0080] 40 Third pinion element

[0081] 42 Steering shaft end components

[0082] 44 Steering shaft bearing

[0083] 46. ​​Axis of rotation

[0084] 48. Central plane

[0085] 50 (serrated slope) serrations

[0086] 50A, 50B, 50C Figure 11 and Figure 12 The sawtooth slope in the middle

[0087] 52 First tooth surface

[0088] 54 Second tooth surface

[0089] 56 Tips

[0090] 58 Tooth base

[0091] 60 (center serration 20) serration base

[0092] 62 (50 teeth) serration base

[0093] 64 Inclined plane

[0094] 70 (for pinion components) serrations

[0095] The sawtooth teeth of 70A, 70B, and 70C (pinion components), such as... Figure 11 and Figure 12 As shown

[0096] 72 (First rolling curve of the first sawtooth slope)

[0097] 74 (Second rolling curve of the second sawtooth slope)

[0098] 76 (the third rolling curve of the first pinion element)

[0099] 78 (the fourth rolling curve of the second pinion element)

[0100] 80( Figure 5 The central sawtooth of the pinion element in the middle

[0101] 82 bearing

[0102] 84 Spacers

[0103] 86 (the serration base of the pinion element)

[0104] 88 normal

[0105] 90° angle bisector

[0106] 92( Figure 10B (Comparative example) central tooth

[0107] 94( Figure 10B The base of the central tooth 92 in the comparative example

[0108] 96( Figure 10B (Comparative example) teeth

[0109] 98( Figure 10B The base of tooth 96 in the comparative example

[0110] 100 motor

[0111] 102 Steering Axle Accessories

Claims

1. A sawtooth component (10) for use in a progressive steering system, having first and second inclined sawtooth ramps (14, 16), the first and second inclined sawtooth ramps comprising a plurality of sawtooths (20, 50), each sawtooth having a first tooth face angle and a second tooth face angle relative to a central plane (48) extending perpendicular to a longitudinal direction (34) of the sawtooth component (10), characterized in that, For at least 50% of the serrations (20, 50) of a plurality of serrations, a first tooth face angle has a unique first angle value and a second tooth face angle has a unique second angle value, wherein the first angle value corresponds to the mirror image of the second angle value on the central plane (48).

2. The serrated component (10) according to claim 1, characterized in that, For at least 70% or at least 90% of the plurality of saw teeth (20, 50), the first tooth surface angle has the first angle value, and the second tooth surface angle has the second angle value.

3. The serrated component (10) according to claim 1, characterized in that, For at least 50%, at least 70%, or at least 90% of the plurality of serrations (50) having a serrated base (62) inclined relative to the longitudinal direction (34) of the serrated member (10), the first tooth surface angle has the first angle value, and the second tooth surface angle has the second angle value.

4. The serrated component (10) according to claim 1, characterized in that, For the tooth profile angle of each tooth (20, 50), the first angle value and the second angle value are allowed to deviate by ±20%.

5. The serrated component (10) according to claim 1, characterized in that, The first and second angle values ​​are x ± 10%, where x is a value between 25° and 40°.

6. The serrated component (10) according to claim 1, characterized in that, The first and second inclined sawtooth ramps (14, 16) are arranged with opposite slopes.

7. The serrated component (10) according to claim 1, characterized in that, The central plane (48) is perpendicular to the base plane (32) of the serrated component (10).

8. The serrated component (10) according to any one of claims 1 to 7, characterized in that, The component (10) has a central serration (20) having a serration base (60) larger than the serration base (62) of each laterally adjacent serration (50).

9. The serrated component (10) according to any one of claims 1 to 7, characterized in that, The first inclined sawtooth ramp (14) is designed for the first rolling curve (72), and the second inclined sawtooth ramp (16) is designed for the second rolling curve (74), wherein each of the rolling curves (72, 74) extends obliquely relative to the central plane (48) and deviates from the straight rolling curve by at most 10° for at least 50% of its extension.

10. The serrated component (10) according to any one of claims 1 to 7, characterized in that, The first inclined sawtooth ramp (14) is designed for the first rolling curve (72), and the second inclined sawtooth ramp (16) is designed for the second rolling curve (74), wherein each of the rolling curves (72, 74) extends linearly and inclined relative to the central plane (48) except for deviations used to correct the progress of the traveling mechanism and / or the universal joint error.

11. The serrated component (10) according to claim 1, characterized in that, The first inclined sawtooth ramp (14) is designed for the first rolling curve (72), and the second inclined sawtooth ramp (16) is designed for the second rolling curve (74), wherein the first and second rolling curves (72, 74) are both non-linear, and wherein the first and second rolling curves (72, 74) are not mirror-symmetric to each other.

12. The serrated component (10) according to any one of claims 1 to 7, characterized in that, In the side view, the first inclined sawtooth ramp (14) is arranged in the plane in front of the plane of the second inclined sawtooth ramp (16) in the viewing direction.

13. The serrated component (10) according to claim 12, characterized in that, The serrated component includes a third serrated ramp (18), which is substantially identical in configuration to the first inclined serrated ramp (14) in a side view and is arranged in a plane behind the plane of the first inclined serrated ramp and the second inclined serrated ramp (14, 16) in the viewing direction.

14. The serrated component (10) according to any one of claims 1 to 7, characterized in that, At least some of the saw teeth (50A, 50B, 50C) have different dimensions.

15. A progressive steering system comprising a sawtooth component (10) according to any one of claims 1 to 14 and a pinion component (12) having a plurality of pinion elements (36, 38), each pinion element being associated with a sawtooth ramp (14, 16) and arranged to engage or disengage with the associated sawtooth ramp (14, 16) according to a corresponding steering angle.

16. The steering system according to claim 15, characterized in that, The serrated component (10) is capable of moving substantially in the longitudinal direction (34).

17. The steering system according to claim 15 or 16, characterized in that, The serrated component (10) presses against the pinion component (12) under the action of spring load, and can move at least 0.1 mm relative to the pinion component (12) along the direction of the central plane (48).

18. The steering system according to claim 15, characterized in that, Each pinion element (36, 38) has a plurality of serrations (70), each serration having a serration base (86) whose normal (88) passes alongside the axis of rotation (46).

19. The steering system according to claim 15, characterized in that, The steering system also includes a motor (100) with a motor shaft, which is torsionally connected to the pinion assembly (12) or via a planetary gear.

20. A method for manufacturing a serrated component (10) according to any one of claims 1 to 14, characterized in that, The serrated component (10) is manufactured by forging, impact extrusion, flow stretching, or sintering.

21. A method for manufacturing a steering gear according to any one of claims 15 to 19, characterized in that, The serrated component (10) is manufactured by forging or impact extrusion or flow stretching or sintering, and / or each pinion element (36, 38, 40) is manufactured by impact extrusion or flow stretching or stamping.

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