Intermediate Steering Shaft for a Motor Vehicle

Abstract

An intermediate steering shaft for a motor vehicle includes a profile element inserted into a hollow profile shaft to form a circulating device. The profile element includes a second peripheral track segment associated, respectively, to a plurality of guide arrangements.

Claims

1. An intermediate steering shaft for a motor vehicle the intermediate steering shaft comprising: an outer hollow shaft including an inner surface; an inner hollow shaft positioned at least partially in the outer hollow shaft; a hollow profiled shaft positioned in the outer hollow shaft and connected rotationally conjointly to the inner hollow shaft; a plurality of guide arrangements configured to (i) guide the hollow profiled shaft in an axial direction in the outer hollow shaft and (ii) transmit a torque of the outer hollow shaft to the hollow profiled shaft, each of the plurality of guide arrangements including: a respective guide mechanism positioned on an outer surface of the hollow profiled shaft; and a respective plurality of balls; and a profile element inserted into the hollow profiled shaft so as to form a circulation device, wherein: the circulation device includes a closed circulation track, and is configured to guide the multiplicity respective plurality of balls of each of the plurality of guide arrangements in an endless series in the closed circulation track the closed circulation track has: a respective first circulation track portion assigned to each guide arrangement, the respective first circulation track portion arranged such that the respective plurality of balls, when in the respective first circulation track portion, is located between the respective guide mechanism and the inner surface of the outer hollow shaft; and the profiled element includes a respective second circulation track portion of the closed circulation track that is assigned to each guide arrangement.

2. The intermediate steering shaft as claimed in claim 1, wherein: the circulation device further includes a receiving portion; the respective second circulation track portion is arranged between the receiving portion of the circulation device and an inner surface of the hollow profiled shaft; and the respective second circulation track portion is arranged substantially parallel to the respective first circulation track portion.

3. The intermediate steering shaft as claimed in claim 1, wherein the hollow profiled shaft includes, at each axial end portion of the respective first circulation track portion, a respective opening in a radial direction, the respective opening connecting the respective first circulation track portion to the respective second circulation track portion.

4. The intermediate steering shaft as claimed in claim 1, wherein: the respective plurality of balls of each of the guide arrangements includes: a first plurality of balls having a first diameter; and a second plurality of balls having a second diameter that is smaller than the first diameter; and the respective plurality of balls are arranged such that, in each case, a respective ball of the first diameter and a respective ball of the second diameter are adjacent to each other.

5. The intermediate steering shaft as claimed in claim 4, wherein: the first plurality of balls are formed from steel, and are configured to transmit the torque acting on the outer hollow shaft to the hollow profiled shaft; and the second plurality of balls are formed from steel or plastic, and are configured as spacers of the first plurality of balls.

6. The intermediate steering shaft as claimed in claim 5, wherein: the first diameter is configured such that the first plurality of balls are configured to make contact with the respective guide mechanism and the inner surface of the outer hollow shaft; and the second diameter is configured such that the second plurality of balls exhibit radial play between the respective guide mechanism and the inner surface of the outer hollow shaft.

7. The intermediate steering shaft as claimed in claim 3, further comprising: a respective diverting element inserted into the respective opening at each axial end portion of the respective first and second circulation track portions, the diverting element configured to divert the respective plurality of balls from the respective first circulation track portion into the respective second circulation track portion and vice versa.

8. The intermediate steering shaft as claimed in claim 7, wherein: the respective guide mechanism has: at least one guide rail positioned, at least in portions, between the outer surface of the hollow profiled shaft and the respective plurality of balls; and an elastic element formed as an O-ring; the outer surface of the hollow profiled shaft and the at least one guide rail have, in each case, a respective mutually adjacently arranged recess configured to receive the elastic element; and the respective diverting elements are configured to hold the elastic element in position.

9. The intermediate steering shaft as claimed in claim 7, wherein the respective diverting elements are formed from plastic, and include a coating formed from PTFE.

10. The intermediate steering shaft as claimed in claim 7, wherein: the circulation device and the respective diverting elements fix each other in position, in an assembled state; the circulation device fixes the respective diverting elements in the axial direction and in the radial direction; and the respective diverting elements fix the circulation device in the axial direction.

11. The intermediate steering shaft as claimed in claim 8, wherein the at least one guide rail has, at respective axial end portions in a region of the respective openings, a bevel such that a shape of the at least one guide rail is adapted to a circular shape, and is formed substantially in the radial direction.

12. The intermediate steering shaft as claimed in claim 1, wherein: the hollow profiled shaft ribs located in respective edge regions of the respective guide arrangement; and the outer hollow shaft further includes at least one projection formed on the inner surface, the projection configured to transmit the torque acting on the outer hollow shaft to the ribs of the hollow profiled shaft in response to a failure of the respective guide arrangement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The appended drawings are intended to convey further understanding of the embodiments of the invention. They illustrate embodiments and serve, in conjunction with the description, for explaining principles and concepts of the invention.

[0024] Other embodiments, and several of the stated advantages, will emerge with regard to the drawings. The illustrated elements of the drawings are not necessarily shown to scale with respect to one another.

[0025] In the drawings:

[0026] FIG. 1 is a schematic illustration of an intermediate steering shaft for a motor vehicle as per a preferred embodiment of the invention;

[0027] FIG. 2 shows a longitudinal sectional view of a sub-portion, indicated in FIG. 1, of the intermediate steering shaft as per the preferred embodiment of the invention;

[0028] FIG. 3 shows a cross-sectional view, in the section plane B-B illustrated in FIG. 2, of the intermediate steering shaft for a motor vehicle as per the preferred embodiment of the invention;

[0029] FIG. 4 shows a cross-sectional view, in the section plane C-C illustrated in FIG. 2, of the intermediate steering shaft for a motor vehicle as per the preferred embodiment of the invention;

[0030] FIG. 5 is a schematic illustration of a circulation device of the intermediate steering shaft for a motor vehicle as per the preferred embodiment of the invention;

[0031] FIG. 6 shows a longitudinal sectional view of a sub-portion of the intermediate steering shaft as per the preferred embodiment of the invention;

[0032] FIG. 7 shows a side view of a guide rail of the intermediate steering shaft as per the preferred embodiment of the invention;

[0033] FIG. 8 is a schematic illustration of the guide rail of the intermediate steering shaft as per the preferred embodiment of the invention;

[0034] FIG. 9 is a schematic illustration of the intermediate steering shaft having a guide arrangement as per the preferred embodiment of the invention; and

[0035] FIG. 10 is a schematic illustration of a diverting element of the intermediate steering shaft as per the preferred embodiment of the invention.

[0036] In the figures, the same reference designations are used to denote identical or functionally identical elements, parts or components, unless stated otherwise.

[0037] FIG. 1 is a schematic illustration of an intermediate steering shaft for a motor vehicle as per a preferred embodiment of the invention.

[0038] The intermediate steering shaft 1 for a motor vehicle has an outer hollow shaft 10, an inner hollow shaft 12 and a profiled shaft (not shown in FIG. 1) which connects the outer hollow shaft 10 and the inner hollow shaft 12 to one another. The intermediate steering shaft 1 is connected at a first end to a first ball joint 61 and at a second end to a second ball joint 62. The intermediate steering shaft 1 can be telescopically lengthened and shortened proceeding from an initial position in order to compensate relative movements that occur between a driver's cab and a chassis during driving operation of the motor vehicle, such that said relative movements do not have an adverse effect on the steering characteristics of the vehicle. The intermediate steering shaft 1 furthermore has, on an end of the outer hollow shaft 10 at which the inner hollow shaft 12 emerges from the outer hollow shaft 10, a stripper 63 which preferably has a seal.

[0039] Thus, in the event of a rotation of the outer hollow shaft 10 effected by means of a rotational movement of a steering column of the motor vehicle, the torque is transmitted to the inner hollow shaft 12 and from the latter to a steering gear of the motor vehicle.

[0040] FIG. 2 shows a longitudinal sectional view through a sub-portion, indicated in FIG. 1, of the intermediate steering shaft as per the preferred embodiment of the invention.

[0041] The intermediate steering shaft 1 is shown in FIG. 2 in the assembled state. Here, a hollow profiled shaft 14 has been inserted into the outer hollow shaft 10, which hollow profiled shaft is connected to an inner hollow shaft 12. The connection between the hollow profiled shaft 14 and the inner hollow shaft 12 is preferably a welded connection.

[0042] The hollow profiled shaft 14 is connected rotationally conjointly to the inner hollow shaft 12. The intermediate steering shaft 1 furthermore has a multiplicity of guide arrangements 15 which guide the hollow profiled shaft 14 in an axial direction R.sub.A in the outer hollow shaft 10. The guide arrangements 15 are designed to transmit a torque of the outer hollow shaft 10 to the hollow profiled shaft 14. The multiplicity of guide arrangements 15 has guide means 16 arranged in each case at an outer surface 14a of the hollow profiled shaft 14, and a multiplicity of balls 20.

[0043] The intermediate steering shaft 1 furthermore has a circulation device 21. The circulation device 21 is designed to guide the multiplicity of balls 20 of each of the multiplicity of guide arrangements 15 in an endless row in a closed circulation track 22, wherein the dosed circulation track 22 has in each case one first circulation track portion 22a and one second circulation track portion 22b. The multiplicity of balls 20 are, in the first circulation track portion 22a, arranged between the guide means 16 and an inner surface 10a of the outer hollow shaft 10. The circulation device 21 is formed by a profiled element inserted into the hollow profiled shaft 14. The profiled element has the second circulation track portion 22b assigned in each case to the multiplicity of guide arrangements 15.

[0044] The second circulation track portion 22b is formed preferably in each case between a receiving portion 21a of the circulation device 21 and an inner surface 14b of the hollow profiled shaft 14. The second circulation track portion 22b is arranged preferably substantially parallel with respect to the first circulation track portion 22a.

[0045] The hollow profiled shaft 14 preferably has, at axial end portions 23a, 23b of the respective first circulation track portion 22a, an opening 17a, 17b formed in a radial direction R.sub.R. The opening 17a, 17b preferably connects the first circulation track portion 22a to the second circulation track portion 22b.

[0046] The multiplicity of balls 20 of each of the guide arrangements 15 has a multiplicity of balls of a first diameter D1 and a multiplicity of balls of a second diameter D2, which differs from the first diameter D1. The first diameter D1 is preferably greater than the second diameter D2. The multiplicity of balls 20 is preferably arranged such that a ball 20a of the first diameter D1 and a ball 20b of the second diameter D2 are arranged in each case adjacent to one another.

[0047] At the axial end portions 23a, 23b of the first and second circulation track portions 22a, 22b, in each case one diverting element 18a, 18b is inserted into the opening 17a, 17b formed in the radial direction R.sub.R of the hollow profiled shaft 14. The diverting element 18a, 18b is preferably designed to divert the multiplicity of balls 20 from the first circulation track portion 22a into the second circulation track portion 22b and vice versa.

[0048] The diverting elements 18a, 18b are preferably formed from plastic and have a PTFE coating. Alternatively, the diverting elements 18a, 18b may for example also be formed from some other suitable material or have some other suitable coating.

[0049] The circulation device 21 and the diverting elements 18a, 18b preferably fix one another in the assembled state. Here, the circulation device 21 fixes the diverting elements 18a, 18b preferably in the axial direction R.sub.A and in the radial direction R.sub.R. The diverting elements 18a, 18b fix the circulation device 21 preferably in the axial direction R.sub.A. Alternatively, some other type of mutual fixing of the circulation device 21 and of the diverting elements 18a, 18b is conceivable.

[0050] FIG. 3 shows a cross-sectional view of the section plane B-B, illustrated in FIG. 2, of the intermediate steering shaft for a motor vehicle as per the preferred embodiment of the invention.

[0051] The balls 20a, 30a, 40a of the first diameter D1 are preferably formed from steel. The balls 20a, 30a, 40a of the first diameter D1 are preferably designed to transmit torque acting on the outer hollow shaft 10 to the hollow profiled shaft 14. The balls 20b, 30b, 40b of the second diameter D2 are preferably formed from steel. Alternatively, the balls 20b, 30b, 40b of the second diameter D2 may for example be formed from plastic. The balls 20b, 30b. 40b of the second diameter D2 are preferably spacers of the balls 20a, 30a, 40a of the first diameter D1.

[0052] The balls 20a, 30a, 40a of the first diameter D1 make contact in each case with the guide means 16, 26, 36 and with the inner surface 10a of the outer hollow shaft 10. The balls 20b, 30b, 40b of the second diameter D2 preferably exhibit radial play in each case between the guide means 16, 26, 36 and the inner surface 10a of the outer hollow shaft 10.

[0053] The guide means 16, 26, 36 have at least one guide rail 19a, 19b, 29a. 29b, 39a, 39b and an elastic element 31, 41, 51 in the form of an O-ring. The at least one guide rail 19a, 19b, 29a, 29b, 39a, 39b is arranged in certain portions between the outer surface 14a of the hollow profiled shaft 14 and the multiplicity of balls 20, 30, 40. The outer surface 14a of the hollow profiled shaft 14 and the at least one guide rail 19a, 19b, 29a, 29b, 39a, 39b have in each case one mutually adjacently arranged recess 32, 42, 52 for receiving the elastic element 31, 41, 51. Here, the respective diverting elements 18a, 28a, 38a hold the elastic element 31, 41, 51 in position. Alternatively, some other suitable arrangement is for example conceivable.

[0054] FIG. 4 shows a cross-sectional view of the section plane C-C illustrated in FIG. 2 of the intermediate steering shaft for a motor vehicle as per the preferred embodiment of the invention.

[0055] In FIG. 4, it is possible to dearly see a difference in dimensions between the balls 20a of the first diameter and the balls 20b of the second diameter. The balls 20b of the second diameter in this case preferably exhibit radial play between respective wall surfaces of the diverting element 18a, 28a, 38a. Likewise preferably illustrated is the relatively small dimensioning (in relation to conventional devices of this type) of the circulation device 21 which is inserted into the hollow profiled shaft 14. This furthermore results in a weight saving. The respective diverting elements 18a, 28a, 38a, which are inserted into the corresponding openings 17a, 27a, 37a of the hollow profiled shaft, furthermore advantageously have, on a respective outer wall, wedge-shaped elements (not illustrated in FIG. 4) which, after the insertion of the diverting elements 18a, 28a, 38a into the openings 17a, 27a, 37a, effect a detent engagement of the diverting elements into the openings, such that said diverting elements are securely arrested in the openings 17a, 27a, 37a.

[0056] FIG. 5 is a schematic illustration of a circulation device of the intermediate steering shaft for a motor vehicle as per the preferred embodiment of the invention. The circulation device 21 preferably has a multiplicity of, in the present exemplary embodiment three, receiving portions 21a which are designed to, in the inserted state of the circulation device, receive the profiled hollow shaft (not shown in FIG. 5) in each case the multiplicity of balls in order to guide these in the dosed circulation track (not shown in FIG. 5).

[0057] FIG. 6 shows a longitudinal sectional view of a sub-portion of the intermediate steering shaft as per the preferred embodiment of the invention. The multiplicity of balls 20 are preferably guided in the first circulation track portion 22a. Respective axial end portions 19c, 19d of the guide rail 19a preferably have a bevel 43 which makes it possible for the multiplicity of balls 20 to more easily protrude into, or be guided in, the openings 17a. 17b of circular form of the hollow profiled shaft 14.

[0058] FIG. 7 shows a side view of a guide rail of the intermediate steering shaft as per the preferred embodiment of the invention. The guide rail 19a preferably has the bevel 43 in the illustrated region. The bevel 43 is preferably designed to form, in the assembled state of the guide rail, a shape such that the multiplicity of balls (not shown in FIG. 7) to guide into the opening of the hollow profiled shaft, which is of circular form in the radial direction of the hollow profiled shaft, without becoming jammed with the guide rail 19a.

[0059] FIG. 8 is a schematic illustration of the guide rail of the intermediate steering shaft as per the preferred embodiment of the invention. The illustration shown in FIG. 8 shows a three-dimensional form of the bevel 43 of the guide rail 19a. In this way, the guide rail 19a can advantageously adapt to the circular shape of the opening (not illustrated in FIG. 8) of the hollow profiled shaft.

[0060] FIG. 9 is a schematic illustration of the intermediate steering shaft having a guide arrangement as per the preferred embodiment of the invention. The diverting elements 18a, 18b are inserted into the openings (not illustrated in FIG. 9) of the hollow profiled shaft 14 such that these protrude in certain portions out of the openings. The diverting elements 18a, 18b thus advantageously form axial delimitations for the multiplicity of balls, such that said balls cannot move beyond the defined delimitation in the axial direction.

[0061] FIG. 10 is a schematic illustration of a diverting element of the intermediate steering shaft as per the preferred embodiment of the invention. The illustrated diverting element 18b preferably has the wedge-shaped element 18c on an outer wall. The wedge-shaped element 18c is preferably arranged severalfold around the outer wall of the diverting element 18b and serves, during the insertion of the diverting element 18b into the opening (not illustrated in FIG. 10) of the hollow profiled shaft, as a detent lug for the secure arresting of the diverting element 18b in the opening of the hollow profiled shaft.

[0062] Even though the present invention has been described above on the basis of preferred exemplary embodiments, it is not restricted to these and may be modified in a variety of ways. In particular, the invention may be changed or modified in numerous ways without departing from the essence of the invention.

[0063] For example, a shape, dimensioning or machining or production method of the components of the intermediate steering shaft may be modified.

LIST OF REFERENCE DESIGNATIONS

[0064] 1 Intermediate steering shaft [0065] 10 Outer hollow shaft [0066] 10a Inner surface of the outer hollow shaft [0067] 10b, 10c, 10d Projection [0068] 12 Inner hollow shaft [0069] 14 Profiled hollow shaft [0070] 14a Outer surface of the hollow profiled shaft [0071] 14b Inner surface of the hollow profiled shaft [0072] 15, 25, 35 Guide arrangements [0073] 15a, 15b, 25a, 25b, 35a, 35b Edge regions of the guide arrangements [0074] 16, 26, 36 Guide means [0075] 17a, 17b, 27a, 37a Opening [0076] 18a, 18b, 28a, 38a Diverting element [0077] 18c Wedge-shaped element [0078] 19a, 19b, 29a, 29b, 39a, 39b Guide rail [0079] 20, 30, 40 Balls [0080] 20a, 30a, 40a Balls of a first diameter [0081] 20b, 30b, 40b Balls of a second diameter [0082] 21 Circulation device [0083] 21a Receiving portion of the circulation device [0084] 22 Circulation track [0085] 22a First circulation track portion [0086] 22b Second circulation track portion [0087] 23a, 23b Axial end portions [0088] 24a, 24b Axial end portions [0089] 31, 41, 51 Elastic element [0090] 32, 42, 52 Recess [0091] 33, 53, 73 Ribs [0092] 43 Bevel [0093] 61, 62 Ball joint [0094] 63 Stripper [0095] D1 First diameter [0096] D2 Second diameter [0097] R.sub.A Axial direction [0098] R.sub.R Radial direction