Patent ID: 12215738

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG.1shows a suspension arrangement1with a solid drive axle which is formed as a rigid axle and has a rigid axle body2. Referring to a positive vehicle longitudinal direction x corresponding to the forward driving direction, the rear axle is arranged behind a cross member3extending in a vehicle transverse direction y and, on each vehicle side, a support4extending substantially in a vehicle vertical direction z. In an upper link plane referring to the positive vehicle vertical direction z, the rigid axle is pulled by an axle guide link which is spread in a V-shape, extends substantially in vehicle longitudinal direction x and is formed as a three-point link5. The three-point link5is formed symmetrically with reference to a plane defined by the vehicle longitudinal direction x and the vehicle vertical direction z and has two molecular joints via which it is connected to the cross member3. Further, the three-point link5has a central joint11for connecting the three-point link5to the rigid axle body2so as to be rotationally and swivelably moveable, the rotating and swiveling movements being enabled by a ball joint arranged inside of the central joint11. The central joint11moves up and down during driving operation substantially in vehicle vertical direction z due to deflecting and rebounding movements of the rigid axle body2.

In a lower link plane, the rigid axle is pulled through two trailing arms6, which are arranged outside of the vehicle parallel to one another in vehicle transverse direction y and extend in vehicle longitudinal direction x. The trailing arms6are connected each at one end to the rigid axle body2and each at the other end to a lower force introduction region7of one of the two supports4. The end regions of the trailing arms6are swivelable around a swiveling axis extending in vehicle transverse direction y relative to the lower force introduction region7and rigid axle body2. The suspension arrangement1has a longitudinal beam9on each side of the vehicle at which the rigid axle body2is supported via pneumatic springs12. The two longitudinal beams9extend parallel to one another in vehicle longitudinal direction x and, together with the cross member3, make up a component part of a vehicle frame10. The terms vehicle longitudinal direction x, vehicle transverse direction y and vehicle vertical direction z are used in the following analogous toFIG.1.

FIG.2shows a three-point link5of a utility vehicle that is formed to be spread in a V-shape and has two tubular control arms13which, form an acute angle relative to one another and meet each at one end in a central joint11. The two control arms13are connected in each instance rigidly at one of two shafts14of the central joint11. Each of the two control arms13is rigidly connected at a free end to a guide joint which is formed in each instance as a molecular joint15. The three-point link5is connectable to a vehicle frame10via the molecular joints15and to a rigid axle via a flange plate16of the central joint11. Accordingly, the three-point link5is formed as an axle guide link for guiding a rigid axle.

As will be seen fromFIG.3, the central joint11has a cylindrical dome17that extends in an axial direction a which extends substantially perpendicular to a plane defined by the two control arms13. In the depicted undeflected idle position of the central joint11, the axial direction a does not extend exactly perpendicular to the plane defined by the two control arms13but rather deviates from the latter by 10 degrees. This deviation is necessary so that the structural component parts of the central joint11that move relative to one another in the installed condition of the three-point link5during a deflection and rebound of a rigid axle body2during a driving operation do not collide. In the present case, the undeflected idle position of the central joint11is at the same time the installed position in an unladen utility vehicle. The central joint11has a joint ball18, which at the same time constitutes an inner race of a ball joint and is penetrated by the dome17. In order to prevent a complete separation of the central joint11, the central joint11has a captive securing device19which extends in a radial direction r oriented perpendicular to the axial direction a. The captive securing device19is likewise penetrated by the dome17and is secured at the same time against axial withdrawal from the dome17by an annular securing element20. The annular securing element20viewed in axial direction a is arranged on a side of the captive securing device19remote of the joint ball18and simultaneously engages in a circumferential groove21of the dome17. The annular securing element20is snugly surrounded in radial direction r by the captive securing device19so as to prevent the annular securing element20from coming loose from the circumferential groove21of the dome17because the annular securing element20cannot move out of the circumferential groove21of the dome17in radial direction r.

The annular securing element20is virtually completely circumferentially surrounded by the captive securing device19in radial direction r, this annular securing element19having a circumferential interruption which is required in order to allow the annular securing element19to be inserted into the circumferential groove21of the cylindrical dome17. The captive securing device19makes full surface contact with the annular securing element20such that the annular securing element20in turn contacts the captive securing device19to form a contact surface which substantially surrounds the dome17. This contact surface is formed as a quarter-circle curve when viewed in an axial section through the central joint11. The annular securing element20, which is formed toroidal and has a circular full cross section at the same time, makes full surface contact with the circumferential groove21of the cylindrical dome17. The annular securing element20contacts the groove21of the cylindrical dome17to form a contact surface surrounding the dome17. When viewed in an axial section through the central joint11, this contact surface is formed as a semicircular curve. Accordingly, the annular securing element20is snugly surrounded in a positive-locking manner by the circumferential groove21of the cylindrical dome17and by the captive securing device19particularly over three fourths of its entire outer circumferential surface area; or, in other words, only one fourth of the entire outer circumferential surface area of the annular securing element20is exposed.

The captive securing device19is preloaded in axial direction a by a spring element22which is formed as an O-ring22from an elastomer material. The O-ring22is compressible in axial direction a by somewhat more than one half of the thickness of the annular securing element20to allow the annular securing element20to be mounted. The spring element22is surrounded in axial direction a and simultaneously also in radial direction r by the dome17and by the captive securing device19. The spring element22preloading the captive securing device19in axial direction a is arranged between the captive securing device19and a circumferential shoulder23of the dome17, which circumferential shoulder23extends in radial direction r. In the area of the circumferential shoulder23of the dome17, the captive securing device19has an inner diameter which is greater than the outer diameter of the surrounding shoulder23of the dome17. In this way, the captive securing device19can be moved in axial direction a of the central joint11past the shoulder23when compressing the spring element22in the course of mounting the annular securing element20. In the mounted condition of the central joint11, an annular surface area of the captive securing device19facing the joint ball18is at the same level as the shoulder23of the dome17in axial direction. At the same time, the above-mentioned annular surface area which would function as a stop surface for the joint ball18if separation of the central joint were imminent extends in radial direction r.

When viewed in parallel projection in axial direction a, the captive securing device19partially covers the joint ball18. However, in this way, in the mounted state of the central joint11, it is possible for the joint ball18to axially withdraw from the dome17after a prior shearing off of the toroidal securing element20made of high-strength spring steel accompanied by the formation of a cylindrical shell-shaped shearing surface. The three-point link5is formed as an axle guide link for guiding a rigid axle with a rigid axle body2similar toFIG.1. At the same time, the dome17is formed integral with the flange plate16to connect the central joint11to the rigid axle.

FIG.4shows a central joint11which differs from the central joint11shown inFIG.3in that the captive securing device19covers portions of an inner contour of a housing24of the central joint11viewed in parallel projection in axial direction a. This arrangement has the advantage that a separation of the central joint11is prevented in case the joint ball18should disengage from a bearing shell26surrounding the joint ball18due to wear. The bearing shell26is a component part of a ball joint. The ball joint is formed from the joint ball18which is also referred to as inner race of the ball joint and from the bearing shell26which is also referred to as outer race of the ball joint.

A central joint11of a three-point link5known from the prior art and shown inFIG.5has a housing24which is mounted so as to be rotationally and swivelably movable relative to an axle connection of the central joint11by a ball joint. Further, the central joint11has a captive securing device19which functions as a stop and which extends perpendicular to the centerline of the axle connection and prevents a separation of the housing24and axle connection in the event of failure of the ball joint. A securing element which is formed as a retaining ring25with rectangular cross section constitutes an axial securing element and prevents a withdrawal of the captive securing device in direction of the centerline of the axle connection. The axle connection has a cylindrically-shaped dome17which has a centerline which is coextensive with the centerline of the axle connection. The retaining ring25with rectangular cross section engages in a circumferential, likewise rectangular groove21of the cylindrical dome17. In an arrangement of this kind, there is a risk during driving operation that the retaining ring will come loose as is shown schematically in the enlarged detail.

As will be apparent fromFIG.6, the annular securing element20of the central joints11according toFIG.3andFIG.4has a circular full cross section and is simultaneously formed as a circumferentially uninterrupted torus made from a high-strength spring steel. Geometrically, the annular securing element20corresponds to that of a round-wire snap ring for shafts in accordance with DIN 7993, type A.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.