STEERING OR TRACK ROD HAVING AN INTEGRAL CONNECTING PIPE

Abstract

A connecting tube for connecting two joint attachments of a steering or track rod. The connecting tube is reinforced by at least one tube section connected by friction force to the connecting tube such that either the entire outer or inside wall the tube section is in contact against a wall of the connecting tube, thereby forming a press fit connection. The steering or the track rod has a connecting tube with end sections that each hold or support components of joint attachments. A method for producing a connecting tube or the steering or the track rod in which first a tube semifabricate of the tube section is positioned within a tube semifabricate of the connecting tube and then the two tube sernifabricates are expanded within a connection zone by a mandrel with an oversized section that is moved along the common axial direction of the two tube semifabricates.

Claims

1-15. (canceled)

16. A steering rod (10, 30) or a track rod comprising: a connecting tube (11, 31, 41), end sections (19, 32, 33) of the connecting tube (11, 31, 41), in each case, holding components of joint attachments (12, 34, 35), the connecting tube (11, 31, 41) being reinforced, in some areas, by a tube section (13, 39, 40) connected by friction to the connecting tube (11, 31, 41), and the tube section (13, 39, 40) being in contact, over an entire surface of its outer wall (14) or its inside wall, against a wall (24) of the connecting tube (11, 31, 41) and thereby forms a press fit connection.

17. The steering rod (10, 30) or the track rod according to claim 16, wherein the connecting tube (41) is straight over its length.

18. The steering rod (10, 30) or the track rod according to claim 16, wherein a shape of the connecting tube (11, 31) deviates from straightness along its length.

19. The steering rod (10, 30) or track rod according to claim 18, wherein the tube section (13, 39) is arranged in an area of a curved portion (15) of the connecting tube (11, 31).

20. The steering rod (10, 30) or the track rod according to claim 16, wherein the connecting tube (11, 31, 41) or the tube section (13, 39, 40) undergoes ail-round radial plastic deformation within a mutual connection zone (16, 42), and the connection zone is spaced away from the end sections of the connecting tube (11, 31, 41).

21. The steering rod (10, 30) or the track rod according to claim 16, wherein the connecting tube (11, 31, 41) and the tube section (13, 39, 40) undergo all-round radial plastic deformation within a mutual connection zone (16, 42), and the connection zone is spaced away from the end sections of the connecting tube (11, 31, 41).

22. The steering rod (10, 30) or the track rod according to claim 16, wherein a material from which the connecting tube (11, 31, 41) is manufactured from and a material from which the tube section (13, 39, 40) is manufactured from have different yield strengths.

23. The steering rod (10, 30) or the track rod according to claim 22, wherein the material of the connecting tube (11, 31, 41) has a higher yield strength than the material of the tube section (13, 39, 40).

24. The steering rod (10, 30) or the track rod according to claim 16, wherein a wall thickness (17) of the tube section (13, 39, 40) is smaller than a wall thickness of the connecting tube (11, 31, 41).

25. The steering rod (10, 30) or the track rod according to claim 16, wherein a diameter of at least one of the end sections (19, 32, 33, 48) of the connecting tube (11, 31, 41) is reduced.

26. The steering rod (10, 30) or the track rod according to claim 16, wherein at least one of the connecting tube (11, 31, 41) and the tube section (13, 39, 40) is in a form of a seamless, cold-drawn steel tube.

27. The steering rod (10, 30) or the track rod according to claim 16, wherein at least one of the connecting tube (11, 31, 41) and the tube section (13, 39, 40) is in a form of a longitudinally seam-welded steel tube.

28. A method for producing a steering rod (10, 30) or a track rod which comprises a connecting tube (11, 31, 41), end sections (19, 32, 33) of the connecting tube (11, 31, 41), in each case, hold components of joint attachments (12, 34, 35), the connecting tube (11, 31, 41) is reinforced, in some areas, by a tube section (13, 39, 40) connected by friction to the connecting tube (11, 31, 41), and the tube section (13, 39, 40) is in contact, over an entire surface of its outer wall (14) or its inside wall, against a wall (24) of the connecting tube (11, 31, 41) and thereby forms a press fit connection, the method comprising: positioning a tube semifabricate of the tube section (13, 39, 40) inside a tube semifabricate of the connecting tube (11, 31, 41); and expanding the two tube semifabricates within a connection zone (16, 42) by a mandrel (44) with an oversized section that is moved in a common axial direction of the two tube semifabricates.

29. The method according to claim 28, further comprising reducing the diameter of at least one the end sections (19, 32, 33, 48) of the connecting tube (11, 31, 41), and this diameter reduction being carried out by a die (49) with a conical inlet (50), which is pushed over the outer circumference of the connecting tube (11, 31, 41) and moved in the axial direction of the connecting tube (11, 31, 41).

30. A steering rod or a track rod comprising a connecting tube having end sections, and each of the end sections of the connecting tube supporting a component of a joint attachment, and an area of the connecting tube being reinforced by a tube section, and an entirety outer surface of the tube section being in contact with an interior surface of the connecting tube, forming a press fit connection between the tube section and the connecting tube.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Below, the invention is explained in more detail with reference to drawings that show embodiments presented only as examples, wherein the same indexes refer to the same components or elements. The figures show:

[0042] FIG. 1: A perspective view of a front axle of a utility vehicle, with steering components according to the prior art;

[0043] FIG. 2: A sectioned view of a steering rod with a curved connecting tube, according to a first embodiment of the invention;

[0044] FIG. 3: An enlarged, not-to-scale detailed view of the detail X in FIG. 2;

[0045] FIG. 4: Partially sectioned view of a steering rod with a curved connecting tube, according to a second embodiment of the invention;

[0046] FIG. 5: Schematic representation of a method for producing a connecting tube of a steering rod according to a third embodiment;

[0047] FIG. 6: An enlarged detailed view of the detail Y in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] FIG. 1 shows a front axle 1 of a utility vehicle known from the prior art, having a steering linkage comprising a steering rod 2 and a track rod 3. The steering rod, orientated essentially in the longitudinal direction 4 of the vehicle, and the track rod 3, orientated essentially in the transverse direction 5 of the vehicle, are in functional connection by way of a lever arrangement. The track rod 3 has a straight connecting tube 6. The steering rod 2 has a curved connecting tube 7. The track rod extends in the transverse direction 5 of the vehicle and connects a track lever 8 of a wheel carrier on a first side of the vehicle to a track lever, obscured by another component, of the opposite wheel carrier on the other side of the vehicle. The steering rod 2 extends essentially in the longitudinal direction 4 and connects a lever of a steering gear system to a steering lever 9 associated with one of the two wheel carriers connected by the track rod 3.

[0049] FIG. 2 shows a steering rod 10 with a connecting tube 11 that connects two joint attachments of the steering rod 10 to one another, only one of the joint attachments 12 being shown in the figure. The joint attachment 12 is arranged at one end of the connecting tube 11. The connecting tube 11 is reinforced in one area by a tube section 13 connected to the connecting tube by friction force, such that the outer wall 14 of the tube section 13 is in contact all over its surface against the inside wall 24 of the connecting tube 11, forming a press fit connection. The length of the tube section 13 is shorter than the length of the connecting tube 11. Over their lengths the connecting tube 11 and the tube section 13 each have a constant, circular cross-sectional area, and the extension of the connecting tube 11 deviates from a straight line, forming a curved portion 15. The tube section 13 is arranged in the area of this curved portion 15 of the connecting tube 11. The connecting tube 11 and the tube section 13 are plastically deformed all round within a mutual connection zone 16 which is a distance away from the ends of the connecting tube 11.

[0050] Since the tube section 13 is in contact all over the surface of its outer wall 14 against the inside wall 24 of the connecting tube 11, forming a press fit connection, the length of the connection zone 16 corresponds to the length of the tube section 13. The connection zone 16 extends on one side beyond the curved section 15 in the direction toward one end of the connecting tube 11. Consequently, in addition to the curved area, namely the curved portion 15, the connecting tube 11 is also reinforced in a straight area adjacent to the curved portion 15. The material of the connecting tube 11 has a higher yield point than the material of the tube section 13, such that the yield point of the connecting tube material has a value of 460 MPa and that of the tube section material a value of 355 MPa. Thus, the difference between the two yield point values is 105 MPa.

[0051] The wall thickness 17 of the tube section 13 is smaller than the wall thickness 18 of the connecting tube 11. An end section 19 of the connecting tube 11 has a reduced diameter compared with the diameter of the connecting tube 11. Merging into its end section 19 of reduced diameter, the connecting tube 11 has an all-round conically shaped transition zone. The connection zone 16 and the end section 19 are at a distance away from one another. The end section 19 with reduced diameter has a grooved profile 20 not illustrated separately, with grooves uniformly apart in the axial direction. The joint attachment is in the form of a radial ball joint 12 with a shank 21. The shank 21 has a grooved profile whose shape matches that of the grooved profile 20 of the end section 19. The shank 21 is held all round by the end section 19, and is connected thereto by hot stamping. The radial ball joint 12 has a housing 22 in which a spherical end section of a bail stud 23 is arranged, with the ball stud 23 extending essentially at a right-angle to the extension direction of the end section 19 and the shank 21. The connecting tube 11 and the tube section 13 are in the form of seamless, cold-drawn precision steel tubes according to EN 10305-1, which undergo a normalizing heat treatment. As is made clear by FIG. 3, the transition zone from the sections of the connecting tube 11 not plastically deformed to the connection zone 16 is of conical shape all round.

[0052] FIG. 4 shows a steering rod 30 with a connecting tube 31, wherein the end sections 32, 33 of the connecting tube 31 each hold parts of joint attachments 34, 35. The joint attachments are in the form of radial ball joints 34, 35, and in each case a shank 36 of the radial ball joint 34, 35 is held by the associated end section 32, 33 of the connecting tube 31. The shank 36 and the end section 32 are connected permanently to one another by a grooved profile 37 with grooves parallel to one another and spaced uniformly apart in the axial direction of the shank 36 and the end section 32. One of the two radial ball joints 35 is connected to the connecting tube 31 in such manner that it can be moved in the axial direction of the end section 33, in order to enable fine adjustment of the distance apart from one another of the radial ball joints 34, 35. The fine adjustment is in this case carried out by virtue of a thread arrangement which enables axial displacement of the (not visible) shank relative to the end section 33 of the connecting tube 31. After fine adjustment, the set position of the radial ball joint 35 relative to the connecting tube 31 can be secured by a clamp 38 that encloses the end section 33 of the connecting tube 31. The end section 33 of the connecting tube 31 has two longitudinal slots in order to provide some yield and thereby to enable clamping by the clamp 38. The connecting tube 31 has a shape that deviates from straightness. In one area the connecting tube 31 is reinforced by a tube section 39 connected by friction to the connecting tube 31, with the tube section 39 in contact over its entire outer wall surface against the inside wall of the connecting tube 31, forming a press fit connection.

[0053] FIG. 5 illustrates a method for producing a connecting tube 41 of a steering rod, wherein a tube semifinished part of a tube section 40 is positioned inside a tube semifinished part of the connecting tube 41 and the two tube semifinished parts are then expanded within a connection zone 42 by a mandrel 44 with an oversize section which is moved in the common axial direction 43 of the two tube semifinished parts. In this way a frictional press fit is formed between the two mating parts. The tube semifinished parts are straight, seamless, cold-drawn steel tubes, each cut to the required length. The tube semifinished part of the tube section 40 is positioned in the tube semifinished part of the connecting tube 41 by means of a counterblock 45 that can be pushed into the tube semifinished part of the connecting tube 41, which acts as a stop and can be seen in FIG. 6. Between the tube semifinished part of the tube section 40 and the tube semifinished part of the connecting tube 41 there is preferably a clearance fit with a relatively small clearance gap, so that the two joint partners can be moved relative to one another without much force.

[0054] The expansion of the tube semifinished part of the tube section 40 and the semifinished part of the connecting tube 41 within the connection zone 42 by means of the oversize mandrel 44 moving in the common axial direction 43 of the two semifinished parts 40, 41 preferably takes place continuously in the axial direction 43. The mandrel 44 is not oversized over its full length in the axial direction 43, but only in a relatively small area of its length which is in the form of an annular bead 46. In this way the deforming force required for the expansion can be kept relatively small. Over the rest of its length the mandrel 44 has essentially a circumferential clearance 47 in order to minimize the friction between the mandrel 44 and the inside wall of the tube semifinished part of the tube section 40. When the tube semifinished part of the tube section 40 is on the inside, the expansion takes place in such manner that within the connection zone 42, the tube semifinished part of the tube section 40 and the tube semifinished part of the connecting tube 41 undergo a residual plastic deformation along with a slight increase of their respective outer diameters. The result of this procedure is that in the event of failure of the frictional press fit between the joint partners, the position is secured by a form-enclosing action that once the connecting tube 41 has been finished, keeps the tube section 40 in position in the axial direction 43 within the connecting tube 41.

[0055] An end section 48 of the connecting tube 41 has its diameter reduced, this diameter reduction taking place by means of a die 49 with a conical inlet 50 moving in the axial direction 43, the die 49 being pushed over the outer circumference of the connecting tube 41. On its side facing toward the connecting tube 41, the die 49 has a conical inlet 50 with an opening angle of 14 degrees. The die 49 is pushed on with the mandrel 44 inserted in the connecting tube 41, and in the area where the die 49 is pushed onto the connecting tube 41 the mandrel 44 has an outer diameter that corresponds to the inside diameter of the end section 48 with the reduced diameter. In this way any buckling of the connecting tube 41 while the die 49 is being pushed on can be counteracted. The diameter reduction of the connecting tube 41 takes place during the same clamping operation as the expansion of the tube semifinished part of the tube section 40 and the tube semifinished part of the connecting tube 41. Over its length, the connecting tube 41 is straight.

INDEXES

[0056] 1 Front axle [0057] 2 Steering rod [0058] 3 Track rod [0059] 4 Longitudinal direction of the vehicle [0060] 5 Transverse direction of the vehicle [0061] 6 Connecting tube of the track rod [0062] 7 Connecting tube of the steering rod [0063] 8 Track lever [0064] 9 Steering lever [0065] 10 Steering rod [0066] 11 Connecting tube [0067] 12 Joint attachment [0068] 13 Tube section [0069] 14 Outer wall of the tube section [0070] 15 Curved portion [0071] 16 Connection zone [0072] 17 Wall thickness of the tube section [0073] 18 Wall thickness of the connecting tube [0074] 19 End section [0075] 20 Grooved profile [0076] 21 Shank [0077] 22 Housing [0078] 23 Ball stud [0079] 24 Inside wall of the connecting tube [0080] 30 Steering rod [0081] 31 Connecting tube [0082] 32 End section [0083] 33 End section [0084] 34 Joint attachment, radial ball joint [0085] 35 Joint attachment, radial ball joint [0086] 36 Shank [0087] 37 Grooved profile [0088] 38 Clamp [0089] 39 Tube section [0090] 40 Tube section [0091] 41 Connecting tube [0092] 42 Connection zone [0093] 43 Axial direction [0094] 44 Mandrel [0095] 45 Counterblock [0096] 46 Bead [0097] 47 Clearance [0098] 48 End section [0099] 49 Die [0100] 50 Conical inlet