Control arm and knuckle assembly

An assembly including a control arm and a steering knuckle, one of the control arm and the steering knuckle having a first end with a ball, the other of the control arm and the steering knuckle having a socket that includes a bearing structure formed so as to surround a portion of the ball to securely fasten the ball to the socket. The control arm has a bayonette configuration to receive a first node and a second node is cast directly onto the control arm.

FIELD OF THE INVENTION

The present invention relates to a coupling assembly. The present application illustrates embodiments of the present invention, including embodiments relating to automotive couplers, such as control arm/steering knuckle assemblies for motor vehicles.

BACKGROUND OF THE INVENTION

Control arms are used in motor vehicles to assist with supporting and controlling the respective wheels of the motor vehicle. Typically, control arms can be found connected between the frame of the motor vehicle and a wheel assembly, particularly between the frame and a steering knuckle. Control arm construction is generally complicated for a number of reasons including, for example, the number and the nature of the connections between the control arm and other vehicle components and also because of the performance demands and stresses placed on control arms.

Control arms have been formed by joining a pair of stamped steel pieces together or by hydroforming as disclosed in WO 03/101767 for an Hydroformed Control Arm. Other examples of known control arms are disclosed in U.S. Pat. Nos. 6,070,445 to Holierhock; and 6,098,437 to Kocer et al.

Prior art control arms tend to be bulky due to the high performance demands and stresses. The bulkiness limits the turning radius capabilities of the vehicle steering.

The steering knuckle operably engages the control arm through a ball joint. The ball joint involves a separate element attached to both the control arm and to steering knuckle. Prior art ball joints utilized with steering mechanisms are disclosed in U.S. Pat. Nos. 5,556,119 to Buchner et al. and 6,308,970 to Stuart.

U.S. Patent Application Publication No. 2004/0091306 to Wasylewski et al. discloses a snap fit coupler for ball joint connecting a stabilizer bar to the vehicle.

SUMMARY OF THE INVENTION

The disadvantages of the prior art may be overcome by providing a compact control arm with an integrated node.

One aspect of the invention relates to a control arm assembly comprising a tubular steel body having a first end arcuately extending to a second end. The first end has a first node configured for mounting the first end for rotation about a first axis. The body has a second node affixed thereto intermediate the first and second ends. The second node is configured for mounting the control arm for rotation about the first axis. The first end has a bayonette configuration receiving a bushing assembly and a fastener retains said bushing assembly.

DESCRIPTION OF ILLUSTRATED EMBODIMENTS

FIGS. 1-5illustrate a control arm assembly10operatively engaging a steering knuckle50. The control arm assembly includes a control arm20, a first connection node30, and a second connection node40. As generally known in the art, the control arm20has three engagement points with connection nodes30and40of the control arm assembly10adapted to be pivotally connected to portions14and16of a vehicle chassis and/or other vehicle suspension elements, and a third point for rotary connection comprising a end fitting60engaging the steering knuckle50in a ball and socket joint connecting to a vehicle wheel18and/or other vehicle suspension or steering elements.

The control arm20has a tubular steel body62having connection node30at a first end and an end fitting60at an opposite distal end. Connection node40is affixed to the control arm20intermediate the first end and the opposite distal end. The connection node30defines an axis of rotation of the control arm20. The connection node40also defines an axis of rotation that is coincident with the axis of rotation of the connection node30.

The control arm20is preferably arcuate in shape where the first end extends along the axis of rotation of the connection node30and bends approximately 90° so that the opposite distal end extends substantially normal to the axis of rotation.

The first end of the control arm20has a first reduced diameter portion33and a second reduced diameter portion35. The first portion provides a bearing surface that receives connection node30. The exterior surface of portion35is threaded and receives fastener37. The first end provides a bayonette style mount for the node30. Preferably, the first portion33and second portion35are rotary swaged to build wall thickness.

The first connection node30includes bushing assembly comprising a bushing29, extending between an outer sleeve27and an inner sleeve25. A first bracket31and a second bracket32are mounted on the sleeve27and configured for connecting the control arm20to a first portion14of, for example, a vehicle chassis. Fastener37retains the node30on the control arm20.

The end fitting60is, in a first embodiment, a substantially spherical ball connected to the body62by a neck90. Preferably, the body62and the end fitting60are integrally formed as a one-piece unitary construction. However, as illustrated inFIG. 7, the main portion130could be provided with a screw portion134and the end fitting60′ is threaded to main portion130, which in turn is threaded into the end of the tube20′.

The control arm20may be formed from any appropriate tubular high strength steel, preferably high strength spring steel having a yield strength of at least 760 MPa. The control arm20may be formed by rotary swaging or hydroforming as disclosed in WO 03/101767 for a Hydroformed Control Arm.

It is noted that the embodiments disclosed herein may be applied to a variety of control arm assemblies of different shapes and of different types of joints from that shown herein.

As illustrated, the connection node40is rigidly attached to control arm20. The connection node40receives a bushing41within a tubular sleeve43. Sleeve43integrally extends from a webbed arm45that extends from a mounting sleeve47. Preferably, connection node40is cast in aluminum, or magnesium or other appropriate material directly on the control arm20. The preferred method of casting is disclosed in PCT application no. CA 06/000820, filed May 19, 2006, entitled Controlled Pressure Casting. Some other methods of casting are disclosed in U.S. Pat. Nos. 5,381,849 to Fussnegger and 6,216,763 to Ruehl et al.

The second connection node40pivotally secures the control arm20to a second portion16of, for example, a vehicle chassis. The connection nodes30and40may also pivotally couple the control arm20to other elements, for example, vehicle suspension elements.

As best seen inFIGS. 3 and 4, the steering knuckle50includes a complimentary fitting for end fitting60, comprising a circular cavity or recessed socket51that forms a hollowed-out portion of the steering knuckle50. The socket51may be formed in a variety of ways, including being integrally formed during the creation of the knuckle or formed as a post-manufacturing process, such as by boring or other methods. The socket51has a bottom70and a side wall72and is sized to receive the bearing44.

Bearing44has an outer configuration to be positioned within the recess forming the socket51of the knuckle50and an inner configuration to provide a bearing surface for the end fitting60of the control arm20when the end fitting60is positioned within the socket51. The bearing44and the socket51form the socket part of a ball-and-socket joint58between the control arm20and the knuckle50with the end fitting60of the control arm20forming the ball part of the joint58.

Although the bearing44within socket51may be formed in various ways and take various configurations, one embodiment of the bearing44is illustrated inFIGS. 1-5as a multi-piece bearing having an inner bearing member53and an outer bearing member54. Inner bearing member53may be, for example, molded from an organic plastic, such as NYLON, and then secured into socket51with a press fit Adhesives or other fastening mechanisms may also be employed together or in combination to secure the entire bearing44in socket51. Preferably, the shape and configuration of the top74and side76of bearing member53conforms to the shape and configuration as the bottom70and side72of socket51, respectively. Inner surface78of inner bearing53is preferably spherically shaped in a concave manner to have substantially the same shape and configuration as end fitting60so that end fitting60can move smoothly within socket51against inner surface78.

In one illustrated mode of construction, after end fitting60is inserted into socket51, the outer bearing54is secured into socket51to secure end fitting60into socket51.

The outer bearing54may have an outer surface80that conforms to the side72of socket51and a concave inner surface82that is substantially the same shape and configuration as the portion of end fitting60that it contacts. The outer bearing54may also have a flange84that is pressed against the outer perimeter of socket51. As best seen inFIG. 5, the outer bearing may be formed in two, semi-circular pieces,54aand54bthat may be positioned into socket51after end fitting60has been inserted into socket51. Together the two pieces54aand54bwould form a circular bearing structure that would contact portions of the end fitting60that are adjacent to neck90. The two pieces54aand54bmay mechanically or adhesively connect or interlock with each other once inserted into the socket51. Once assembled, the bearings53and54form a circular bearing structure that encompasses end fitting60around most of its outer surface88except the area directly adjacent to the neck90of the control arm20. Thus, the shape of bearing44complements the shape of the end fitting60and forms a connection between the socket51and the end fitting60with a high efficiency of space.

Bearing members53and54may be formed of any appropriate bearing material. For example, bearing members53and54may be molded of polymer materials such NYLON or fluorocarbon polymers like TEFLON.

While the bearing53has been shown as being inserted first into the socket51and prior to the insertion of the end fitting60, other configurations and methods are possible. For example, both bearings53and54may be formed on the end fitting60and then the end fitting60together with bearing53and43may be inserted into the socket51so that the end result looks substantially as shown in the figures. In such a configuration bearing54may be a one-piece, unitary configuration. Also, only one of bearings53and54may be formed on the end fitting60and the one bearing would then inserted into socket51when the end fitting60is inserted.

The illustrated embodiment ofFIGS. 1-5also includes a tubular flexible seal52that extends between the steering knuckle50and the main portion62of the control arm20to keep and debris away from the ball-and-socket joint58. Thus, the seal52helps keep the connection between the end fitting60and the bearings53and54as free as possible from unwanted particles that could hamper the free movement of the end fitting60within the socket and/or deteriorate the rotary ball-and-socket joint58.

Seal52extends around control arm20and has a generally tubular cross-section. At one end, seal52has flange52aextending into an annular recess61in the control arm20to secure the seal52to the control arm20. The other end of the seal52tightly abuts the surface of the steering knuckle50, adjacent the flange84of the outer bearing54. Adhesives may also be used to secure seal52to steering knuckle50and control arm20. The seal52may be attached between the control arm20and the steering knuckle50in other manners, such as those that are generally known for attaching such seals. The seal52may be attached to the control arm20after the ball-and-socket joint58is formed.

Although the embodiment ofFIGS. 1-5illustrates that the end fitting60is attached to control arm20while the complementary socket51for the socket portion of the ball-and-socket joint58is within the steering knuckle50, this situation may be reversed. That is, the socket portion of the ball-and-socket joint58may be formed in the control arm20while the ball portion of the ball-and-socket joint58may be formed on the steering knuckle50.

FIG. 6illustrates another embodiment of a rotary ball-and-socket joint158. A single bearing144is employed in place of the multi-piece bearing assembly using bearings53and54. Once installed in socket51and around end fitting60, the shape and configuration of bearing144would be substantially identical to that of bearings53and54. However, since bearing144is integrally formed as a one-piece, unitary element the entire bearing144may be secured into the socket51in a single operation. Then, the end fitting60may be forced into the bearing144and into position within the socket51to a position as substantially illustrated as a final assembly inFIG. 4. Of course, the outer end of the bearing144, especially the bearing flange184and the adjacent area of bearing144will be sufficiently resilient to deform and permit the end fitting60to ingress into bearing144and into socket51while returning to an original position to lock the end fitting60within the socket51.

Bearing144may be formed of the same material as above with respect to bearings53and54and bearing144may be substantially identical to bearing44except for the two-piece configuration of bearing44. Further, other arrangements with bearing144are possible including initially forming the bearing144on end fitting60and inserting the end fitting60along with the bearing144simultaneously into socket51while the bearing144is secured in socket51.

Referring toFIG. 7, an alternate embodiment for forming a flexible joint between the steering element and control arm is illustrated. Rather than rotary swaging an end fitting60on the end of the tube, tube20′ has an internal thread that receives a main portion130. Portion130has a threaded portion132that threadingly engages with the tube20′ and screw portion134. Screw portion134threadingly receives end fitting60′ or other steering element to control arm end fitting, well known in the art. Housing130has an annular groove61′ configured for receiving boot52.

This embodiment has the advantage that if the end fitting is damaged or worn, the end fitting can be replaced or repaired rather than replacing the entire control arm.

Referring toFIG. 8, an alternate embodiment of the control arm20″ is illustrated. The control arm20″ has a first reduced diameter portion33and a second reduced diameter portion35and a cast second node40, similar to the embodiment ofFIGS. 1-5. A different form of end fitting230is provided on the distal end of the control20″. End fitting230may be cast directly on the end of the tube20″ or alternately threaded onto the end of the tube20″

Referring toFIG. 9, an alternate embodiment of the control arm20′″ is illustrated. The control arm20′″ has a first reduced diameter portion33and a second reduced diameter portion35and a cast second node40, similar to the embodiment ofFIGS. 1-5. Control arm20′″ has a different form of end fitting comprising a first reduced portion333and a second reduced diameter portion335, providing a bayonette style mount on both ends of control arm20′″.

The preferred order of manufacture is that a straight tube is swaged and machined to form a workpiece. The workpiece is then bent to the desired arc. The arcuate workpiece is then placed in a mold and the node40is then cast directly onto the workpiece to form control arms20,20′,20″, and20′″.

The proposed control arms20,20′,20″, and20′″ require less space and less material and achieve improved dimensional tolerances for vehicle wheel suspension systems. As a result, the illustrated embodiments of the subject application result in a knuckle/control arm interface that requires less space, less weight, less cost, fewer parts, and improved dimensional tolerance of the assembly relative to previous knuckle/control arm joints.

The foregoing specific embodiments have been provided to illustrate the structural and functional principles of the present invention, and are not intended to be limiting. To the contrary, the present invention is intended to encompass all modifications, alterations, and substitutions within the scope of the appended claims.