Suspension for a non-driven steerable vehicle wheel

Wheel suspension for a non-driven steerable vehicle wheel, comprising a kingpin (3) fixed in a front wheel beam (1), said kingpin having upper and lower bearings (17, 18), by means of which a wheel spindle (12) is pivotally mounted relative to the beam. The upper bearing is a roller taper bearing and the lower bearing is a journal bearing (18) consisting of an outer sleeve of an elastically deformable plastic material and an inner bearing bushing of a bearing metal.

BACKGROUND OF THE INVENTION
 The present invention relates to a wheel suspension for a non-driven
 steerable vehicle wheel, comprising an axle member, which at each end has
 a conical through-bore, which holds a conical central portion of a
 kingpin, which is provided with kingpin ends extending outside the bore
 into the member, and a spindle unit, having, firstly, spaced upper and
 lower spindle ears holding bearings into which the kingpin ends extend and
 of which the upper bearing is a roller bearing and the lower bearing is a
 journal bearing, and, secondly, an axle end on which a wheel hub is
 intended to be mounted.
 The most common type of steering knuckle arrangement for trucks has the
 spindle unit mounted in a taper roller bearing at the upper end of the
 kingpin and a journal bearing at its lower end. The upper bearing takes up
 both axial and radial forces while the lower bearing only takes up radial
 forces. In such a spindle bearing, the axial force on the upper bearing is
 load-dependent, i.e. the axial load on the bearing varies with the total
 weight of the vehicle. When taking a curve, the radial forces on the lower
 bearing from the kingpin will be such that they strive to tip the lower
 bearing bushing in its seat in the lower spindle ear. Since the bushing is
 forced into its seat and the kingpin is mounted with the minimum possible
 play in the bushing, the bushing cannot even out the force couples which
 apply an asymmetric load. This results in the upper and lower areas of the
 bearing race being subjected to radial forces and greater wear than the
 middle portion, and this in turn can lead to gaps occurring after a
 relatively short time when driving with heavy loads on winding roads.
 SUMMARY OF THE INVENTION
 The purpose of the present invention is to achieve a wheel suspension of
 the type described by way of introduction with a lower kingpin bearing
 which has a longer life than previously known bearings of the type in
 question.
 This is achieved according to the invention by virtue of the fact that the
 journal bearing comprises an outer sleeve of an elastically deformable
 material, which is non-rotatably fixed in a bearing seat in the lower
 spindle ear, and an inner bearing sleeve of a bearing metal, which is
 non-rotatably fixed in the outer sleeve.
 The elastic sleeve allows the bearing sleeve, when obliquely loaded from
 the kingpin when the truck takes a curve when heavily loaded, to be tipped
 somewhat in the bearing seat so that the center axis of the bearing sleeve
 will intersect the center axis of the bearing seat approximately at their
 midpoints, resulting in a reduction of the forces acting on the end
 portions of the bearing sleeve. The result will be a reduction of wear at
 the end portions and an extension of the total life of the lower kingpin
 bearing.

DETAILED DESCRIPTION OF THE INVENTION
 In the FIGURE, 1 designates one end of a front member in a motor vehicle.
 The member 1 has a bore 2 of truncated conical shape along most of its
 length. A kingpin, generally designated 3, has its middle portion 4, with
 the same conicity as the bore 2, fixed in the bore. An upper cylindrical
 kingpin end 5 extends above an upper end surface 6 of the member 1 and has
 a threaded portion 7 at its very end. A corresponding lower cylindrical
 kingpin end 9, but without the threaded portion at the very end, extends
 below a lower end surface 10 on the member 1.
 A wheel spindle, generally designated 12, has an upper spindle ear 13 and a
 lower spindle ear 14, which are each made with an individual bearing seat
 15 and 16, respectively, for an upper taper roller bearing 17 and a lower
 journal bearing 18, respectively, which consists of an outer sleeve 18a of
 an elastically deformable plastic material and an inner sleeve 18b of a
 bearing metal. The upper bearing rests with its outer ring 19 against an
 upwardly facing surface 20 of the upper bearing seat 15. The upper kingpin
 end 5 protrudes into the inner ring 23 of the upper bearing 17, which is
 made in one piece with a spacer sleeve 24, which abuts against the
 upwardly facing surface 6 of the member 1 with an end surface 25. By
 tightening a nut 26 screwed onto the threaded portion 7, the bearing ring
 23 is clamped with its spacer sleeve 24 against the member 1 and is
 rotationally fixed. The lower kingpin end 9 protrudes into the inner
 bearing sleeve 18b of the lower journal bearing 18. Its outer sleeve 18a
 is pressed into the bearing seat 16 in the lower spindle ear 14. The axial
 position of the bearing 18 in the seat 16 is determined by a flange 18c on
 the inner bearing sleeve 18b, said flange forming an abutment against an
 end surface 40 on the lower spindle ear 14. The outer sleeve 18a is
 suitably glued or welded to the inner bearing sleeve 18b. The sleeves,
 during assembly, are pressed as a unit into the bearing seat 16 of the
 lower spindle ear 14. The flange 18c also forms an end abutment against
 one end surface of the elastic sleeve 18a when the sleeves 18a and 18b are
 put together.
 The outer cylindrical surface of the spacer sleeve 24 is made with a
 peripheral groove 27 into which the sealing lips 28 on an elastic sealing
 ring, generally designated 29, extend and abut with their end surfaces
 against the bottom of the groove 27. The flange 27a, formed by the groove
 27, forms an abutment which keeps the seal in place during assembly. The
 portion 30 of the sealing ring 29 opposite the sealing lips 28 has an
 essentially L-shaped cross-sectional profile and is mounted in a seat 31
 in the upper spindle ear 13.
 The upper spindle ear 13 has an inner threaded portion 33 above the bearing
 seat 15, into which an externally threaded flange 34 on a cover 35 is
 screwed, so that a space sealed off by the sealing ring 29 and the cover
 35 is formed for lubricant. The cover 35 is provided with a laterally
 directed grease nipple 36. The entry of the thread is selected so that the
 grease nipple 36, after the cover has been screwed down, will assume a
 predetermined position in which it is easily accessible during service.
 The lower spindle ear 14 has a corresponding internally threaded portion
 37, into which an externally threaded cover 38 with a grease nipple 39 is
 screwed.