FR2644734A1 - DIRECTIONAL AXLE ASSEMBLY WITH PRELOADED SLIDING KEYS FOR WORKING ANCHORS - Google Patents

Abstract

An assembly of a steerable axle having a cross beam defining an elongated vertically oriented hub at one end which defines two vertically spaced ends and is traversed by a bore, the assembly further having a steering knuckle. defining a forked fork having upper and lower arms which have aligned openings corresponding to opposite ends of the bore, the assembly further having a cylindrical kingpin supported in the bore and extending through the openings, the hub having a transverse opening partially intersecting the bore. bore, a sliding key supported therein, and having an elongated head with a flat, tapered surface adapted to engage the kingpin, the key having a threaded shank with one end extending outside the opening, where is screwed a nut for its fixation against the kingpin. According to the invention, a spring 44, 48 is interposed between the hub 14 and the nut 52 for the preliminary load of the sliding key 42 against the kingpin 32. The invention applies in particular to the suspensions of heavy vehicles.

Description

The present invention relates to sets of steerable axles of the

  type using dowels for fixing the steering knuckles to the axle hubs. More particularly, the invention relates to an apparatus adapted to retain a kingpin against rotational movement in an axle hub, despite wear during service life.

useful of the kingpin.

  In conventional front suspension systems for road vehicles such as trucks, the axles of the wheels are connected to the front axles by

  steering rockets and ankles.

  Typically, the rocket has a fork for coupling to a fixed axle hub and the kingpin extends through the aligned openings in the fork and a bore in the axle hub to hold these members together. The normally vertically oriented axle hub, designed to support the steering knuckle, is part of the front axle. The rocket is adapted to pivot around the kingpin on a

vertical axis.

  The axle hub, also called the rocket support hub, thus non-rotatively retains the kingpin but allows the rotation of the rocket. A roller bearing mounted between the rocket support and the lower arm of the forked fork allows low friction movement of the rocket about the steering axis. The upper arm usually supports a

  sleeve to receive a lower load.

  Due to manufacturing tolerances, the roller bearing of the kingpin and the sleeve are often not precisely adjusted between the lower and upper arms of the fork. The spaces or games that result allow the bodies to move relative to each other, especially as a result of wear during the useful life of the parts. In heavy truck suspension systems, the working pins are normally held against rotation by means of sliding keys having tapered surfaces which pass against the sides of the work pins. However, as a result of wear, larger sets are created, allowing worker pins to move and oscillate in their associated rocket holes during the useful life of the parts. Such

  movements exacerbate the problems of wear.

  According to the present invention, an assembly of a steerable axle provides a system of sliding keys for pre-loaded dowel pins, which closes the wear created at the interface of the kingpin and the hub of the steering axle. . In a preferred form, the assembly comprises a transverse axle beam having at its ends two rocket bearing hubs that are vertically oriented. Each of the hubs has vertically spaced ends and a bore extending completely between the ends. A steering knuckle is pivotally attached to each hub by upper and lower arms having aligned openings. A cylindrical dowel passes through the hub hole and the

  openings of the arms to hold the rocket on the hub.

  Each hub contains a transverse opening that extends transversely to and partially intersects the bore and a sliding key is supported in each transverse opening. Each sliding key has an elongated head having a tapered flat surface

  adapted to come in engagement with the kingpin.

  The sliding key has a threaded shank portion that is opposed to the head, the end of which extends outwardly of the transverse opening. A sliding key nut is screwed to the end of the threaded shank portion to hold the head of the slide key against the kingpin. A disc spring washer is used to preload the slide key against the kingpin by virtue of its position between the hub and the nut. In a preferred form, the disk-shaped resilient washer is a Belleville spring that produces a relatively constant tensile load under deformation.

  up to 0.76 mm per sliding key.

  the invention will be better understood, and other purposes, features, details and advantages thereof

  will become clearer during the description

  following explanatory diagram with reference to the accompanying schematic drawings given solely by way of example illustrating an embodiment of the invention, and in which: - Figure 1 is a fragmentary elevational view of an end of an assembly a steerable axle which contains a preferred embodiment of the present invention; Figure 2 is a cross-sectional view of a kingpin and a steering axle hub looking along the line 2-2 of Figure 1; and FIG. 3 is a cross-sectional side view of a pair of disk spring washers used in a preferred form of the present invention where the washers are shown in their form without tension before torque due to the nut of the sliding key. Referring initially to FIG. 1, a fragmentary view of an assembly of a steerable axle shows an end (only the conductive side) of a transverse beam of the front axle 12. The beam has a vertically oriented hub 14 supporting pivotally steering a rocket 16. The rocket 16 has a conventional axis 18 for the wheel and has a steering arm 20 which extends opposite the axis 18. The arm 20 is traditionally connected to a wheelhouse (not shown ) that includes a steering rod coupled to a manually controlled steering wheel controlled by the driver of a vehicle. The rocket 16 has upper and lower arms 22, 24 which together define a bifurcated fork to couple the rocket to the hub 14 by

  a cylindrical kingpin 32.

  The hub 14 includes a vertically oriented internal bore 26 while the upper and lower arms 22 and 24 contain openings 28 and 30, respectively, for connection to the cylindrical kingpin 32. As will be appreciated by those skilled in the art, pin, fixed in the bore and openings by conventional means, supports the rocket 16 for pivotal movement relative to the hub 14 and thus the wheels (not shown), carried by the axis 18, can be rotated around a relatively vertical axis of direction "aa" defined by

the axis of the hole 26.

  Referring now to Figure 2, it shows a cross-sectional view of the kingpin 32 and the hub 14 supporting the rocket. Right and left transverse openings 34 and 36 respectively support a pair of sliding keys 42 which are disposed on opposite sides of the kingpin 32 as can be seen. Each sliding key 42 has a head 38 having a tapered plate 54. Each plate 54 is adapted to engage a corresponding plate 40 on opposite sides of the kingpin, so that the kingpin is effectively prevented from spinning.

in drilling 26.

  Each sliding key also has an unthreaded rod portion 46 which is integral with the head 38. Of the unthreaded rod portion protrudes a threaded rod end 50 which extends outwardly of the transverse opening 34, 36 Each sliding key is held in place by a nut 52 at a

  voltage load of about 276 to 344 kPa.

  Two disk spring washers 44, 48 are interposed between the nut 52 and the opening end surface 60 of the axle 14 as can be seen. In the preferred form, disc spring washers comprise Belleville springs which, when the nuts 52 are tightened, are flattened as shown in FIG. 2. Although the Belleville spring is preferred, other springs may be used. who have

  similar deformation capabilities under load.

  Referring now to Figure 3, it shows a pair of Belleville springs 44, 48 in an unloaded or uncompressed form. FIG. 3 shows a preferred method of stacking the Belleville springs so that their inner circumferential portions 56 come into contact with each other while their outer circumferential portions 58 are adapted to a bearing contact respectively with the nut 52 and the outer open end surface 60. The Belleville springs 44, 48 are adapted to preload the sliding keys to compensate for the wear of the kingpin, and will have a characteristic load curve that is relatively flat. over a wide range of deformation. Thus, over a range of 0.76 mm of deformation, the pair of Bellevilles springs 44, 48 will produce a relatively constant force effective to prevent play or loosening due to the wear of the kingpin, allowing a movement that can reach 0 , 76 mm from the sliding key against the kingpin. In their preferred form, Bellevilles springs have a Rockwell hardness of between 45 and are made of a high carbon steel. All other materials for ankles, hubs, etc. are as traditionally used by those skilled in the art. Finally, in the same preferred form, the sliding keys are arranged to be parallel but axially offset (in FIG. 1) along the kingpin 32 and the conicities are between 5-15 degrees by measuring with respect to the axes "bb" and "cc" sliding keys. Also, in the preferred embodiment, each slidable key head is elongated to be longer than the total threaded end and intermediate threaded portions of the sliding keys. In addition, the sliding keys are in reverse orientation.

Claims (10)

R E V E N D I C A T I 0 N S CLAIMS   A steerable axle assembly, of the type comprising a transverse beam defining an elongate hub vertically oriented at one end, said hub defining a pair of vertically spaced ends and having a bore extending completely between said ends, said assembly comprising plus a steering pivoting spindle defining a bifurcated fork having upper and lower arms, said arms having aligned openings adapted to correspond with opposite ends of said piercing, said assembly further comprising a cylindrical spindle supported in said bore and passing through said apertures said hub including a transverse opening extending transversely to and partially cutting said bore, a sliding key supported in said transverse opening, said sliding key having an elongated head with a tapered flat surface adapted to engage said kingpin, said sliding key having a threaded rod with one end extending outwardly of said transverse opening, on said end being screwed a nut for fixing said sliding key against said kingpin, characterized in that it comprises a spring (44, 48) interposed between said hub (14) and said nut (32) for pre-loading said sliding key (42) against said kingpin (32).   2. An assembly according to claim 1, characterized in that the kingpin (32) has a flat and tapered surface to correspond with said flat and tapered surface on the head (38) of the sliding key. 3. Assembly according to claim 2, characterized in that the spring (44, 48) comprises at least one disc spring washer placed around the threaded shaft.   4. Assembly according to claim 3, characterized in that, during assembly, the tension on the sliding keys (42) is sufficient to deform said disc spring washer to a position totally flattened.   5. An assembly according to claim 3, characterized in that the tensile load on the sliding key (42) is between 276 and 344 kPa.   6. An assembly according to claim 5, characterized in that it further comprises a second sliding key (42) placed parallel to but axially offset from the first sliding key, the kingpin having a second flat and tapered surface which is placed at 180 degrees of the first tapered flat surface, said second surface being axially offset from said first surface and in that said second sliding key also contains a disk spring washer and a nut associated therewith, said washers operating in parallel to produce a relatively constant tensile load under a total strain of up to 0.76 mm sliding key.   An assembly according to claim 6, characterized in that the transverse beam further comprises a second hub (14) at an opposite end, each hub including a pair of cross openings and each of the disc spring washers is a Belleville washer.   8. Assembly according to claim 7, characterized in that the sliding keys and the conicities are in corresponding and parallel alignment, the concitals being between 5 and 10 degrees by   relative to the axis of each sliding key.   9. An assembly according to claim 8, characterized in that the elongated heads of the sliding keys are longer than the rods of said sliding keys.   10. Assembly according to claim 9, characterized in that the sliding keys are in reverse orientation.