Arrangement of a wheel carrier on a steering knuckle

Abstract

Arrangement of a wheel carrier (3) and a brake disc (2) on a steering knuckle (4) of a commercial vehicle, - wherein the wheel carrier (3) and the brake disc (2) are rotatable relative to the steering knuckle (4) about a wheel rotation axis (D) via a rolling bearing (8) - and the axle stub (4) has a hub-like, pot-shaped receptacle (42) open to a rim of a vehicle wheel, in which the rolling bearing (8) is received, - wherein an outer bearing ring (81) of the rolling bearing (8) frictionally rests against an inner surface (44) of the receptacle (42) of the axle journal (4) and an inner bearing ring (82) frictionally rests against an outer surface (56) of a shaft journal (5), - wherein a flange (52) of the shaft journal (5) is connected to the wheel carrier (3) in a rotationally fixed manner, - wherein the shaft journal (5) is axially secured in the receptacle (42) at an end near a steering knuckle bearing (41) of the steering knuckle (4) by means of a bearing nut (13), - wherein the steering knuckle (4) is made of a cast iron material, characterized in that - the shaft journal (5) is designed as a solid shaft journal made of elastic steel, - wherein a transition area (57, 58, 59) of an outer surface (56) of the shaft journal (5) between a cylindrical outer surface of a central part (51) and the flange (52) has at least two curved areas, - wherein a first transition area (57) extending towards the flange (52) on the cylindrical outer surface of the central part (51) is designed as a concavely shaped contact surface for a retaining ring (15).

Description

[0001] The present invention relates to an arrangement of a wheel carrier on an axle stub of a commercial vehicle according to the preamble of claim 1.

[0002] A generic arrangement of wheel carriers and brake discs on the steering knuckles of a commercial vehicle is known, for example, from DE 10 2006 025 555 A1. Wheel carriers of commercial vehicles are often subjected to very high loads. In order to withstand these loads, different materials must be used in a confined space, depending on the strength requirements of the individual components. For example, the brake discs are made of gray cast iron, the axle flange of forged steel, and the wheel carrier, to which the vehicle wheel is attached, of spheroidal graphite cast iron. Another arrangement of wheel carriers and brake discs on the steering knuckles of a commercial vehicle is known, for example, from EP 1 800 996 A1.

[0003] Until now, safety-critical axle components in commercial vehicles were predominantly made from heat-treated steel. A first technical innovation was the introduction of so-called precipitation-hardened ferritic-pearlitic (AFP) steels with added vanadium. These steels have a decisive advantage over the previously used, cost-intensive heat-treated steel, as the final heating stage for hardening can be omitted in its production. This is due to the small alloying addition of vanadium, which, with uniform cooling from hot forming temperature and consistent processing properties, results in similar component characteristics.

[0004] For the design and fatigue strength verification of AFP steel for safety-critical axle components, a curb impact test was defined, among other things. This test simulates sliding and impact of the commercial vehicle perpendicular to the direction of travel against a curb. This extreme load and all other known verification tests have been successfully completed for the aforementioned AFP steels.

[0005] The object of the present invention is to provide an alternative arrangement of a wheel carrier and a brake disc on a steering knuckle, the components of which can be manufactured cost-effectively and are easy to assemble, and which are particularly capable of withstanding the loads of the curb impact test.

[0006] This problem is solved by an arrangement of a wheel carrier and a brake disc on an axle carrier with the features of claim 1.

[0007] Advantageous embodiments of the invention are the subject of the dependent claims.

[0008] In the arrangement according to the invention, the wheel carrier and the brake disc are rotatable relative to the steering knuckle about a wheel axis of rotation via a rolling bearing. The steering knuckle has a hub-like, cup-shaped receptacle open towards the rim of a vehicle wheel, in which the rolling bearing is received. An outer bearing ring of the rolling bearing rests frictionally against an inner surface of the receptacle of the steering knuckle, and an inner bearing ring rests frictionally against a shaft journal, with a flange of the shaft journal being rotationally fixed to the wheel carrier.The shaft journal is designed as a solid shaft journal made of elastic steel, wherein a transition area of ​​the outer surface of the shaft journal between a substantially cylindrical outer surface of a central part and the flange has at least two curved areas, and wherein, in order to reduce stresses, a first transition area extending towards the flange on the cylindrical outer surface of the central part is designed as a concavely shaped contact surface for a retaining ring.

[0009] Such an arrangement is characterized by its cost-effectively manufactured components.

[0010] To meet the safety-critical requirements, the shaft journal is made of an elastic steel that deforms plastically under higher loads but does not break before the shaft journal experiences any noticeable material damage.

[0011] This solution also offers the advantage that in case of damage, only the deformed shaft journal itself needs to be replaced, and not the axle body, which is more complex in terms of manufacturing technology and cost, and is made of cast iron.

[0012] Under the aforementioned curb impact load, the shaft journal experiences a significantly higher load-bearing moment than under other load conditions. The shaft journal's design counteracts this extreme load to a certain extent by incorporating a degree of flexibility in the wheel bearing, as the shaft journal is structurally connected to the wheel carrier.

[0013] Due to the high loads in the area of ​​the axle journal, the higher-stressed point load is distributed over a larger joint diameter, since the cast iron material of the axle body, like previous AFP steel designs, must compensate for the highest loads there. With a smaller journal diameter, significantly higher loads would occur than with the current KB solution.

[0014] Another advantage of load redistribution lies in the axle loads and wheel contact loads to be borne, which indicate a significantly lower moment on the axle journal than with previous design solutions.

[0015] The aforementioned material definition of the axle journal-wheel bearing-hub assembly compensates for extreme loads. For even higher load capacity, the transition area of ​​the shaft journal's outer surface between a substantially cylindrical surface of a central section and the flange is designed to be more stress-resistant.

[0016] Furthermore, replacing the brake disc is also possible in a simple manner, since in particular the wheel bearing no longer needs to be removed for replacing the brake disc and all components are accessible and can be mounted or dismounted from the vehicle wheel side.

[0017] A further reduction of stresses on the shaft journal is achieved by having a second transition area, which follows the first transition area in the direction of the flange, that widens linearly radially towards the flange.

[0018] According to an advantageous further development, a third transition area extending towards the flange from the second transition area is designed as a concave ring surface.

[0019] According to a further embodiment of the invention, the brake disc is designed as a pot brake disc, wherein a pot base of the brake disc together with the wheel carrier is fixed to the shaft journal in a rotationally secure manner in the circumferential direction and thus counteracts the extreme load acting on the shaft journal.

[0020] According to another preferred embodiment, the wheel carrier has an inner, radially extending ring with through holes for screws that are screwed into end-face threaded holes of the shaft journal.

[0021] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a perspective sectional view of an embodiment of an arrangement according to the invention of a wheel carrier and a brake disc on a steering knuckle, and . Fig. 2 a section enlargement of the sectional view according to Fig. 1 to illustrate the wave tap.

[0022] In the following figure descriptions, terms such as top, bottom, left, right, front, rear, etc., refer exclusively to the exemplary representation and position of the wheel carrier, brake disc, steering knuckle, roller bearing housing, shaft journal, and the like as chosen in the respective figures. These terms are not to be understood as restrictive; that is, these references may change due to different working positions, mirror-symmetrical design, or similar factors.

[0023] In Fig. Reference numeral 4 denotes one embodiment of a steering knuckle according to the invention. The steering knuckle 4, made of a cast iron material, preferably spheroidal graphite cast iron, has a steering knuckle bearing 41 which is pivotally connected to an axle carrier 10 about a vertical axis of rotation.

[0024] On the side of the steering knuckle bearing 41 facing away from the axle carrier 10, a hub-like, cup-shaped receptacle 42 and a brake carrier (not shown here) are integrally formed. A brake disc 2 overlaps the receptacle 42 of the steering knuckle 4.

[0025] Fig. Figure 1 further shows a brake cylinder 14, a brake caliper 7 spanning the brake disc 2, and brake pads 6 arranged on both sides of the brake disc 2 in the brake caliper 7. An axle carrier pin 9 is received in the steering knuckle bearing 41 and is rotatably mounted in a recess of the steering knuckle bearing 41.

[0026] A wheel carrier 3 is provided for attaching a vehicle wheel, to which the rim of a (not shown) vehicle wheel can be mounted using a plurality of wheel bolts 11.

[0027] The wheel carrier 3 and the brake disc 2 are, as in Fig. Figure 1 shows that the wheel is rotatably mounted relative to the steering knuckle 4 about a wheel rotation axis D via a rolling bearing 8. For this purpose, the rolling bearing 8 is mounted in the receptacle 42 of the steering knuckle 4.

[0028] As in Fig. 1 and Fig. 2 as can be further seen, an outer bearing ring 81 of the rolling bearing 8 rests frictionally against an inner surface 44 of the receptacle 42 of the axle stub 4, while an inner bearing ring 82, which is connected to the outer bearing ring 81 via rolling elements, rests frictionally against a shaft journal 5, which is connected to the wheel carrier 3 in a rotationally fixed manner.

[0029] The shaft journal 5 is designed as a solid shaft journal made of a deformable material, preferably an elastic steel.

[0030] The brake disc 2 has a friction ring 21 and a pot 22 extending perpendicular to the friction surface of the friction ring 21, the free end of which is arranged between a neck section 32 of the wheel carrier 3 and a flange 52 of the shaft journal 5.

[0031] The brake disc 2 further has a flange area formed on the inner circumference of the pot 22 of the brake disc 2, which is provided with through holes through which screws 12 extend, which are screwed into a ring 34 of the wheel carrier 3 and into end-face threaded holes of the shaft journal 5.

[0032] It is also conceivable to form the wheel carrier 3 and the brake disc 2 in one piece, so that the wheel carrier 3 is formed on the free end of the pot 22.

[0033] The wave pin 5 is, as in Fig. 2 is shown, secured at its end near the axle bearing 41 with a bearing nut 13 in the receptacle 42.

[0034] The bearing nut 13 is arranged between a base 43 of the receptacle 42 and the inner bearing ring 82 and thus fixes the shaft journal 5 axially to the wheel rotation axis D in a predetermined position.

[0035] The shaft journal 5 has a transition area 57, 58, 59 on its outer surface 56 between a substantially cylindrical outer surface of a central part 51 and the flange 52.

[0036] This transition area has at least two curve sections to reduce stresses under load.

[0037] A first transition area 57 extending towards the flange 52 on the cylindrical outer surface of the central part 51 is designed as a concavely shaped contact surface for a retaining ring 15, which serves to axially secure the rolling bearing 8 on the side facing the wheel carrier 3.

[0038] From this first transition area 57, a second transition area 58 extends towards the flange 52, which is radially widening linearly towards the flange 52 and thus increases the diameter of the shaft journal in the direction of the flange.

[0039] From the second transition area 58 towards the flange 52, a third transition area 59 extends, which in turn is designed as a concave ring surface and thus contributes to further stress reduction.

[0040] The shaft journal 5 has indentations on the side facing away from the wheel carrier 3 and on the side facing the axle carrier journal 9. Reference symbol list 2 brake discs 21 Brake ring 22 pots 3 bike carriers 31 Outer ring 32 Neck section 33 lids 34 wreath 4 axle stubs 41 Kingpin bearings 42nd entry 43 Floor 44 interior surface 5 wave pins 51 cone core 52 flange 53 feet 54 indentation 55 indentation 56 outdoor area 57 first transition zone 58 second transition area 59 third transition area 6 brake pads 7 brake calipers 8 rolling bearings 81 Outer bearing ring 82 Inner bearing ring 9 axle carrier pins 10 axle carriers 11 Wheel bolt 12 screws 13 Bearing nut 14 brake cylinders 15 retaining ring D Wheel pivot axis

Claims

[1] Arrangement of a wheel carrier (3) and a brake disc (2) on a steering knuckle (4) of a commercial vehicle, - wherein the wheel carrier (3) and the brake disc (2) are rotatable relative to the steering knuckle (4) about a wheel rotation axis (D) via a rolling bearing (8) - and the axle stub (4) has a hub-like, pot-shaped receptacle (42) open to a rim of a vehicle wheel, in which the rolling bearing (8) is received, - wherein an outer bearing ring (81) of the rolling bearing (8) frictionally rests against an inner surface (44) of the receptacle (42) of the axle journal (4) and an inner bearing ring (82) frictionally rests against an outer surface (56) of a shaft journal (5), - wherein a flange (52) of the shaft journal (5) is connected to the wheel carrier (3) in a rotationally fixed manner, - wherein the shaft journal (5) is axially secured in the receptacle (42) at an end near a steering knuckle bearing (41) of the steering knuckle (4) by means of a bearing nut (13), - wherein the steering knuckle (4) is made of a cast iron material, characterized by , that - the shaft journal (5) is designed as a solid shaft journal made of elastic steel, - wherein a transition area (57, 58, 59) of an outer surface (56) of the shaft journal (5) between a cylindrical outer surface of a central part (51) and the flange (52) has at least two curved areas, - wherein a first transition area (57) extending towards the flange (52) on the cylindrical outer surface of the central part (51) is designed as a concavely shaped contact surface for a retaining ring (15). [2] Arrangement according to claim 1, characterized by , that the shaft journal (5) in a second transition area (58) adjoining the first transition area (57) in the direction of the flange (52) is formed to widen linearly radially towards the flange (52). [3] Arrangement according to claim 2, characterized by, that a third transition area (59) extending towards the flange (52) from the second transition area (58) is formed as a concave ring surface. [4] Arrangement according to any one of the preceding claims, characterized by , that the brake disc (2) is designed as a pot brake disc, wherein a pot base of the brake disc (2) together with the wheel carrier (3) is fixed to the shaft journal (5) in a circumferentially rotationally secure manner. [5] Arrangement according to any one of the preceding claims, characterized by , that the wheel carrier (3) has an inner radially extending rim (34) with through holes for screws (12) which are screwed into end-face threaded holes of the shaft journal (5).

Images