Shaft arrangement and steering gear having a shaft arrangement

Abstract

The invention relates to a shaft arrangement (1) for a steering transmission, having an input shaft (2), having an output shaft (3) and having a torsion bar (5), wherein the torsion bar (5) is connected to the input shaft (2) in an input-side connection region (13) of the shaft arrangement (1) in a torsion-proof manner, wherein the torsion bar (5) is connected to the output shaft (3) in an output-side connection region of the shaft arrangement (3) in a torsion-proof manner, and wherein the input-side connection region is spaced apart from the output-side connection region. According to the invention, the shaft arrangement (1) has a rotation safeguard, wherein the rotation safeguard limits the torsion of the input shaft (2) relative to the output shaft (3) to a maximum rotation angle, and wherein, upon reaching the maximum rotation angle, torque can be transmitted from the input shaft (2) to the output shaft (3). Furthermore, the invention relates to a steering transmission having the previously described shaft arrangement (1).

Description

Technical Field

[0001] This invention relates to a shaft assembly for a steering gear, comprising an input shaft, an output shaft, and a torsion bar, wherein the torsion bar is torsionally connected to the input shaft in an input-side connection region of the shaft arrangement, wherein the torsion bar is connected to the output shaft in an output-side connection region of the shaft arrangement, and wherein the input-side connection region and the output-side connection region are spaced apart. Furthermore, this invention relates to a steering transmission device having a shaft arrangement. Background Technology

[0002] When a vehicle is turned, steering force must be transmitted from the steering wheel to the vehicle's wheels. This is done by means of a steering transmission. A steering transmission typically has a torsion bar, which provides the desired clearance during steering. The torsion bar involves a rotationally elastic element. It connects two shafts of the steering transmission, such as, for example, an input shaft on the steering wheel side and an output shaft on the wheel side. The output shaft may be directly threaded, have a pinion, or something similar, so that the rotational motion of the output shaft can be converted into linear motion.

[0003] Steering transmissions with torsion bars are known in the prior art. Therefore, DE 10 2011 017150A1 describes a steering column with two shaft sections coupled by a torsion bar. The torsion bar is rotationally elastic and arranged inside the shaft sections. This arrangement lacks any safety mechanism in case the torsion bar breaks, for example, due to material fatigue or overload. This would cause the steering system to stop operating.

[0004] DE 10 2014 212 367 A1 describes a steering transmission having a steering input shaft and a pinion shaft coupled to the steering input shaft via a torsion bar. The steering input shaft is supported in a housing. The housing has a locking element. In the event of a steering rod breakage, the locking element restricts axial movement of the steering input shaft. This prevents, in such a case, the magnet of the steering transmission from colliding with a support bearing in which the steering input shaft is guided. Summary of the Invention

[0005] In contrast, the present invention is based on the objective of providing a torsion bar shaft arrangement with enhanced operational safety. Furthermore, the present invention is based on the objective of providing a steering transmission in which safe steering is possible even now, in the event of torsion bar failure.

[0006] These tasks are solved by the shaft arrangement according to the invention and the steering transmission according to the invention. The technical solutions of the invention relate to different, independent, and advantageous extensions of the invention, the features of which can be freely combined by those skilled in the art within a framework of technical significance.

[0007] According to a first aspect of the invention, a shaft arrangement for a steering transmission is provided. The shaft arrangement has an input shaft, an output shaft, and a torsion bar, wherein the torsion bar is torsionally connected to the input shaft in an input-side connection region of the shaft arrangement. Furthermore, the torsion bar is torsionally connected to the output shaft in an output-side connection region of the shaft arrangement. Finally, the input-side connection region and the output-side connection region are spaced apart. According to the invention, the shaft arrangement has a rotational safety mechanism that limits the torsion of the input shaft relative to the output shaft to a maximum rotation angle, and allows torque to be transferred from the input shaft to the output shaft when the maximum rotation angle is reached.

[0008] The key consideration is this fundamental consideration: the shaft arrangement, through the rotational safety feature according to the invention, limits the fundamentally desired torsion of both the input and output shafts to their maximum values. This advantageously and significantly reduces the risk of torsion bar breakage. Furthermore, adverse consequences for the overall system's operational safety are also largely limited, because even if the torsion bar fails, the transmission of rotational motion continues to be borne by the anti-motion protection device according to the invention. Therefore, it is ensured that, even in the event of torsion bar breakage, steering remains possible.

[0009] The rotational safety mechanism allows the input shaft to twist relative to the output shaft up to a maximum rotation angle. According to the invention, the twisting of the input shaft relative to the output shaft can involve rotation about a longitudinal axis arranged around the shaft. If the torsion bar fails, it may no longer be able to transmit any torque from the input shaft to the output shaft. In this case, the rotational safety mechanism ensures that the maximum rotation angle between the input and output shafts is not exceeded. Furthermore, the rotational safety mechanism ensures that the torsion bar does not twist too far, thereby preventing potential damage to the torsion bar. According to the invention, the torsion bar can involve a rod-shaped, rotationally elastic spring element. When the input shaft twists relative to the output shaft, the torsion bar rotates elastically along its length between the input-side connection area and the output-side connection area.

[0010] Advantageously, the rotational safety can be configured such that the torque to be transmitted from the input shaft to the output shaft is transmitted only through the rotational safety.

[0011] Preferably, the rotational safety mechanism comprises a safety pin torsionally connected to the input shaft and a notch in the output shaft, wherein a section of the safety pin is arranged to extend into the notch, and wherein the notch is sized such that a gap exists between the wall of the notch and the safety pin, allowing the input shaft to rotate relative to the output shaft. Thus, a gap or free space exists between the safety pin and the wall of the notch, allowing the input shaft to rotate relative to the output shaft. Rotation is only prevented from continuing when the safety pin contacts the wall. Different geometries are possible for the safety pin, but preferably, it is cylindrical. Similarly, different geometries are possible for the notch; however, these geometries should match the shape of the safety pin. The notch can be implemented, for example, extending completely and more preferably centrally through the output shaft in a direction transverse to the axis of the output shaft, for example, as a channel bore, and the safety pin can pass completely through the notch. If the output shaft is constructed in the region of the notch, for example, hollow inside, then the notch can be constructed on two opposite shell sections of the hollow shaft.

[0012] Advantageously, the recess has opposing safety surfaces against which the safety pin can rest when the input shaft twists relative to the output shaft, wherein the distance between the safety surfaces and each other and / or their angular positions relative to each other determine the maximum rotation angle. Therefore, the notch can, for example, have a wedge-shaped cross-section in a segmental manner, which allows the input shaft to twist relative to the output shaft within certain limits. Advantageously, the notch can be constructed in a wedge-shaped extension when viewed from the outer circumferential surface of the output shaft along the direction of the output shaft's axis. That is, the notch has a larger opening width on the corresponding outer shell surface of the output shaft than on the corresponding axial, inner surface of the shell surface segment of the output shaft.

[0013] Preferably, the input shaft has an input shaft bore on the input side, in which a region of the safety pin is received without clearance. In the context of this invention, a bore should be understood as any hollow space created within the element, regardless of how it is formed. Particularly preferably, the input shaft bore on the input side is arranged transversely to the axis of the input shaft and extends centrally, preferably completely through the input shaft. According to the invention, it is possible that the input shaft bore on the input side has a circular cross-section, wherein the safety pin is cylindrical. The safety pin can be pushed into the input shaft bore on the input side and can be removed from it when needed. Preferably, the center of the input shaft bore on the input side and the center of the previously described notch in the output shaft are aligned with each other.

[0014] Preferably, the safety pin secures the torsion bar to the input shaft in a torsion-resistant connection in the input-side connection area. Therefore, the safety pin serves not only to fix the input shaft relative to the output shaft but also to establish a torsion-resistant connection between the input shaft and the torsion bar. Preferably, this is implemented such that the torsion bar has a torsion bar bore on the input side, and a section of the safety pin is received without gaps in said torsion bar bore. Thus, the safety pin can be arranged in sections in the input shaft bore and the torsion bar bore on the input side, with other sections of the safety pin arranged in notches. Preferably, the input shaft bore and the torsion bar bore on the input side are aligned in a straight line. According to other embodiments of the invention, it is also possible that the safety pin is not used to connect the input shaft to the torsion bar. Then, for example, a connecting pin or other connecting device of the same kind can be inserted into the input shaft and the torsion bar.

[0015] According to the present invention, the output shaft may have an output shaft bore in the connection region on the output side, and the torsion bar may have a torsion bar bore in the connection region on the output side, wherein the connecting pin is received segmentally and without clearance in the output shaft bore and the torsion bar bore on the output side, respectively. In this manner, the torsion bar can be connected to the output shaft in a torsion-resistant manner. However, within the scope of the present invention, other possibilities regarding how the torsion bar can be connected to the output shaft are also conceivable.

[0016] According to a particular embodiment of the invention, the output shaft has a channel extending in the longitudinal direction of the output shaft, in which the torsion bar is arranged at least substantially. Inside the channel, the torsion bar elastically deforms when the input shaft twists relative to the output shaft. Because the torsion bar is arranged inside the output shaft, the shaft arrangement can have a relatively short configuration, as it is not necessary to provide additional spacing for the torsion bar, for example, between the input and output shafts. According to the invention, it is possible that the torsion bar is arranged in the channel of the output shaft at least in the portion extending from the input-side connection area to the output-side connection area. However, according to the invention, the torsion bar can also extend to other areas of the output shaft. According to a variation of the invention, the torsion bar can further extend from one end of the output shaft. Preferably, at least 70%, preferably at least 80%, more preferably at least 90%, and especially at least 95% of the length of the torsion bar, viewed along its axis, is arranged in the channel of the output shaft.

[0017] Preferably, the input shaft has a receiving space at its end facing the output shaft, which receives at least one end segment of the output shaft. Therefore, to connect the input shaft and the output shaft, the output shaft can be pushed into the receiving space of the input shaft. The receiving space can be constructed, for example, cylindrical. Furthermore, advantageously, the receiving space can be constructed as a blind hole. Here, according to an advantageous embodiment of the invention, a rotating safety is arranged at the height of the receiving space. For example, the safety pin described above can be inserted into both the input and output shafts at the height of the receiving space.

[0018] Preferably, not only is the end section of the output shaft received by the input shaft, but the torsion bar is also arranged inside the output shaft at the height of the receiving space. This means that one end of the torsion bar is arranged inside the end section of the output shaft at the height of the receiving space. Particularly preferably, the anti-torsional connection between the torsion bar and the input shaft is constructed at the height of the receiving space. To this end, according to the invention, a safety pin can be inserted into a hole not only in the input shaft but also into a hole in the torsion bar at the height of the receiving space.

[0019] According to an advantageous embodiment of the invention, a member forming an anti-torsional connection between the torsion bar and the input shaft in the input-side connection region constitutes part of a rotational safety device. This member may involve the previously described safety pin or a similar locking element. However, in this embodiment, the exact configuration of the rotational safety device can be freely chosen and is not limited to the previously described variation in which the output shaft has a notch in which a section of the safety pin is disposed.

[0020] Preferably, the output shaft is a threaded shaft. The threaded shaft has external threads. In this invention, the external threads preferably extend along a section of the threaded shaft, at least between the input-side connection area and the output-side connection area. In the steering transmission, the nut (also called a ball recirculation nut) is mostly located on the external threads of the threaded shaft, and the nut is encapsulated in the steering transmission such that it is not rotatable. Therefore, as the threaded shaft rotates, the nut moves axially along the threaded shaft. The nut can, for example, be coupled to a steering arm, through which steering forces are transmitted to the vehicle's wheels. However, in principle, the shaft arrangement according to the invention can also be used in other applications.

[0021] According to another aspect of the invention, a steering transmission device is described, which is equipped with the shaft arrangement previously described. This steering transmission device is preferably constructed such that force can be transmitted from the steering wheel to the input shaft of the shaft arrangement. The input shaft and the output shaft of the shaft arrangement are elastically coupled by means of a torsion bar. Even if the torsion bar breaks or can no longer perform its coupling function for other reasons, steering is still possible via the steering transmission device. This is achieved by a rotational safety mechanism in the shaft arrangement, which limits the torsion of the input shaft relative to the output shaft to a maximum rotation angle and, upon reaching the maximum rotation angle, allows torque to be transmitted from the input shaft to the output shaft. Attached Figure Description

[0022] The illustrations depict advantageous embodiments of the invention. They are shown here:

[0023] Figure 1 A schematic diagram, shown in side view, illustrates the shaft arrangement according to the invention for a steering transmission.

[0024] Figure 2 A schematic diagram showing the arrangement of the output shafts in a side view.

[0025] Figure 3 A schematic diagram showing the arrangement of the axes in cross-section.

[0026] Figure 4 A schematic diagram showing the rotational safety mechanism with axial arrangement in cross-sectional view, and

[0027] Figure 5 A schematic diagram of the rotational safety mechanism with axial arrangement is shown in another cross-sectional view. Detailed Implementation

[0028] Figure 1 A schematic diagram of a shaft arrangement 1 according to the invention for a steering transmission is shown in a side view. Shaft arrangement 1 has an input shaft 2 and an output shaft 3, wherein the output shaft 3 is a threaded shaft. The output shaft 3 is provided with an external thread 4. When shaft arrangement 1 is used in a steering transmission, for example, a nut (also called a ball recirculation nut) can be mounted on the external thread 4, which moves axially along the output shaft 3 as the output shaft 3 rotates, and the nut can couple with the steering arm of the steering transmission. Furthermore, shaft arrangement 1 has a torsion bar 5. The largest part of the torsion bar 5 is arranged inside the output shaft 3 or the input shaft 2 and... Figure 1 Only a small section protrudes from the output shaft 3.

[0029] Output shaft 3 is inserted into input shaft 2 (in) Figure 1The receiving space is not visible in the middle. Furthermore, a safety pin 6 is inserted into the section of the input shaft 2 that has the receiving space. On one hand, the safety pin 6 connects the input shaft 2 to the torsion bar 5 in a torsion-resistant manner. On the other hand, the safety pin 6 limits the torsion of the input shaft 2 relative to the output shaft 3 to the maximum rotation angle. Additionally, the shaft arrangement 1 has a connecting pin 7. This connecting pin 7 is inserted into the end of the output shaft 3 opposite to the input shaft 2. The connecting pin 7 connects the torsion bar 5 to the output shaft 3 in a torsion-resistant manner.

[0030] Figure 2 A schematic diagram showing the shaft arrangement of the output shaft 3 is provided. The output shaft 3 has an output shaft bore 8 on the output side for receiving a connecting pin 7 (not shown). The end section 9 of the output shaft 3 is constructed to be slightly narrower than the other sections of the output shaft 3. The end section 9 of the output shaft 3 can be inserted into the input shaft. A notch 10 is present in the end section 9. Figure 2 The safety pin 6, also not shown, passes through the notch.

[0031] Figure 3 A schematic diagram of axis arrangement 1 is shown in cross-sectional view. This section follows the... Figure 1 The section AA extends. The operating principle of shaft arrangement 1 will be explained in more detail below. Input shaft 2 has a receiving space 11. The end section 9 of output shaft 3 is inserted into the receiving space 11 of input shaft 2. Output shaft 3 has a channel 12 in which a torsion bar 5 is arranged. Torsion bar 5 is anti-torsionally connected to input shaft 2 in the input-side connection area 13 of shaft arrangement 1 by means of a safety pin 6. Safety pin 6 is located without clearance in the input shaft bore 14 on the input side of input shaft 2 and in the torsion bar bore 15 on the input side of torsion bar 5. Furthermore, torsion bar 5 is anti-torsionally connected to output shaft 3 in the output-side connection area 16 of shaft arrangement 1 by means of a connecting pin 7. Connecting pin 7 is located without clearance in the output shaft bore 8 on the output side of output shaft 3 and in the torsion bar bore 17 on the output side of torsion bar 5. Therefore, input shaft 2 and output shaft 3 are connected by torsion bar 5. Because the torsion bar 5 is rotationally elastic, rotational movement of the input shaft 2 relative to the output shaft 3 is possible.

[0032] However, the input shaft 2 should not rotate too far relative to the output shaft 3. Especially in the event of a failure of the torsion bar 5, it should be ensured that torque can always be transmitted from the input shaft 2 to the output shaft 3. The safety pin 6 ensures this. The safety pin 6 passes through a notch 10 in the output shaft 3. The notch 10 is sized such that a gap exists between the safety pin 6 and the wall of the notch 10, allowing the input shaft 2 to rotate relative to the output shaft 3 up to its maximum rotation angle. This is from... Figure 4 and 5 It is understood that notch 10 and safety pin 6 together constitute the rotational safety of shaft arrangement 1.

[0033] Figure 4 A schematic diagram of the rotational safety 18 arranged along the axis is shown in cross-sectional view. This cross-section is along the axis from... Figure 3 The truncated line CC extends. The rotational safety 18 is constructed of a notch 10 and a safety pin 6. The notch 10 is located in the end section 9 of the output shaft 3. The safety pin 6 passes through the notch 10. There is free space between the safety pin 6 and the wall of the notch 10, allowing the safety pin 6 to move within the notch 10. Therefore, it is possible to twist the input shaft 2 relative to the output shaft 3 until a maximum rotation angle is reached, at which point the safety pin 6 rests against the safety surface 20 of the notch 10. Figure 5 )superior.

[0034] Figure 5 A schematic illustration of the rotational safety 18 arranged along the shaft is shown in another cross-sectional view. This section runs along the shaft from... Figure 1 The sectional line BB extends. The safety pin 6 is located without clearance in the input shaft bore 14 on the input side of the input shaft 2 and in the torsion bar bore 15 on the input side of the torsion bar 5. Furthermore, the safety pin 6 passes through the notch 10 of the output shaft 3. Free space 19 lies between the safety surface 20 of the notch 10 and the safety pin 6. Therefore, it is possible to twist the input shaft 2 relative to the output shaft 3 until the safety pin 6 abuts against the safety surface 20. This prevents the torsion bar 5 from being over-twisted, and ensures that the torque transmission from the input shaft 2 to the output shaft 3 can proceed via the safety pin 6 in the event of a failure of the torsion bar 5.

[0035] List of reference numerals

[0036] 1-axis layout

[0037] 2 input axes

[0038] 3 output shafts

[0039] 4 external threads

[0040] 5 Torque Bars

[0041] 6 safety pins

[0042] 7 connecting pins

[0043] 8. Drilling holes in the output shaft on the output side

[0044] 9 end sections

[0045] 10 gaps

[0046] 11 receiving space

[0047] 12 channels

[0048] 13 Input-side connection area

[0049] 14. Drilling holes for the input shaft on the input side.

[0050] Drilling holes for the torsion bar on the input side.

[0051] 16 Output side connection area

[0052] 17. Drilling holes for the torsion bar on the output side

[0053] 18-turn safety

[0054] 19 Free Space

[0055] 20 safety face

Claims

1. A shaft arrangement (1) for a steering transmission, the shaft arrangement having an input shaft (2), an output shaft (3), and a torsion bar (5), wherein, The torsion bar (5) and the input shaft (2) are torsionally connected in the input-side connection area (13) of the shaft arrangement (1), wherein the torsion bar (5) and the output shaft (3) are torsionally connected in the output-side connection area (16) of the shaft arrangement (1), and wherein the input-side connection area (13) and the output-side connection area (16) are spaced apart. The shaft arrangement (1) has a rotation safety (18) that limits the torsion of the input shaft (2) relative to the output shaft (3) to a maximum rotation angle and is able to transmit torque from the input shaft (2) to the output shaft (3) when the maximum rotation angle is reached. The input shaft (2) is a steering wheel-side input shaft and the output shaft (3) is constructed as a threaded shaft. The input shaft (2) has a receiving space (11) at its end facing the output shaft, which receives at least one end section (9) of the output shaft (3).

2. The shaft arrangement (1) according to claim 1, characterized in that, The rotational safety (18) consists of a safety pin (6) connected to the input shaft (2) in a torsion-resistant manner and a notch (10) in the output shaft (3), wherein a section of the safety pin (6) is arranged to extend into the notch (10), and wherein the notch (10) is sized such that there is a gap between the wall of the notch (10) and the safety pin (6), the gap allowing the input shaft (2) to rotate relative to the output shaft (3).

3. The shaft arrangement (1) according to claim 2, characterized in that, The notch (10) has safety surfaces (20) that are opposite each other, and the safety pin (6) can abut against the safety surfaces when the input shaft (2) is twisted relative to the output shaft (3), wherein the distance and / or angular position of the safety surfaces (20) relative to each other determines the maximum rotation angle.

4. The shaft arrangement (1) according to claim 2 or 3, characterized in that, The input shaft (2) has an input shaft bore (14) on the input side, and a section of the safety pin (6) is received in the input shaft bore without gap.

5. The shaft arrangement (1) according to claim 2 or 3, characterized in that, The safety pin (6) enables the torsion bar (5) to be torsionally connected to the input shaft (2) in the input-side connection area (13).

6. The shaft arrangement (1) according to claim 2 or 3, characterized in that, The torsion bar (5) has a torsion bar bore (15) on the input side, and a section of the safety pin (6) is received in the torsion bar bore without gaps.

7. The shaft arrangement (1) according to any one of claims 1-3, characterized in that, The output shaft (3) has an output shaft hole (8) on the output side in the connection area (16) on the output side, and the torsion bar (5) has a torsion bar hole (17) on the output side in the connection area (16) on the output side, wherein the connecting pin (7) is received segmentally in the output shaft hole (8) on the output side and the torsion bar hole (17) on the output side without gaps.

8. The shaft arrangement (1) according to any one of claims 1-3, characterized in that, The output shaft (3) has a channel (12) extending in the longitudinal direction of the output shaft (3), and the torsion bar (5) is arranged at least most of the way in the channel.

9. The shaft arrangement (1) according to claim 8, characterized in that, The torsion bar (5) is arranged in the channel (12) of the output shaft (3) at least in part of the connection area (13) extending from the input side connection area (13) to the output side connection area (16).

10. The shaft arrangement (1) according to any one of claims 1-3 and 9, characterized in that, The rotation safety (18) is arranged at the height of the receiving space (11).

11. The shaft arrangement (1) according to any one of claims 1-3 and 9, characterized in that, The torsion bar (5) is arranged inside the output shaft (3) at the height of the receiving space (11).

12. The shaft arrangement (1) according to claim 11, characterized in that, The anti-torsion connection between the torsion bar (5) and the input shaft (2) is constructed at the height of the receiving space (11).

13. The shaft arrangement (1) according to any one of claims 1-3, 9 and 12, characterized in that, The anti-torsion connection component of the shaft arrangement (1) in the input-side connection area (13) between the torsion bar (5) and the input shaft (2) also constitutes part of the rotational safety (18).

14. A steering transmission having a shaft arrangement (1) according to any one of claims 1 to 13.

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