Torque rod

The present invention is directed to a torque rod comprised of a two piece mating design which increases rigidity and reduces the number of welds. Unlike other designs this design has single piece forged ends which permits the torque rod of the present invention to take greater payloads than other designs can take. The design further includes internal bearings.

BACKGROUND OF THE INVENTION

Torque rods are used to stabilize an axle by transforming motion. They prevent the axle from spinning, prevent fore-aft movements during braking and accelerations, and they prevent axle yaw. Truck, trailer and bus suspensions also utilize torque rods to secure a drive axle to the vehicle's frame. Torque rods are used both as transverse rods to secure the drive axle to a vehicle's frame and as longitudinal rods to attach the suspension system to the vehicle axle. By securing the drive axle to the vehicle's frame using a torque rod, the drive axle's alignment to the vehicle's frame is maintained, and the proper suspension geometry for the vehicle is also maintained, so that free suspension movement is allowed by transferring torque created by the suspension movement on irregular terrain. The longitudinal connection of the suspension system to the axle helps in aligning the axle and acts as a kinematic chain.

Straight arm torque rods have been constructed using any of a welded tube design, cast design, welded solid rod design, or other designs like single piece forged designs. Typically, multiple welds are needed. Three-piece designs were also available with two solid rods welded to the end housings and an intermediate pipe, used to join the pieces together. The bushing ends have been constructed using cartridge type bushings, bonded bushings and also using other polymer designs.

Due to varying operating conditions for vehicles, severe impact loads combined with road vibrations on the suspension cause the components of the suspension, including the torque rods, to be subjected to wear. Dynamic loading conditions can accelerate wear of suspension system components and also lead to fatigue of the vehicle's operator, which may lead to premature failure of several components including torque rods.

There are two primary designs used for torque rods. The first design is a straight arm torque rod with pivot bushings on either end. The second design is the use of wishbone shaped (V-shaped) torque rods with pivotal bushings at the apex and either end of the legs. This latter design controls both fore-aft movements as well as lateral movements. Each application of a torque rod requires a rod that meets the specific needs of that particular vehicle. Because different vehicles require different torque rods, the manufacturing process results in various rods for the various vehicles. Often, mechanics installing torque rods need to cut them for fit, and once cut need to weld the pieces together. Often, multiple cuts and welds are needed. In addition, torque rods in use can fracture or break due to loads or because of wear. Wear may result from poor welds or from abrasives or other contaminants entering the area of the bearings. It would be advantageous to design a torque rod which can sustain high loads while in use, includes protection against excess wear, which can be readily replicated in manufacture, and also be used on a variety of vehicles requiring different length torque rods.

BRIEF DESCRIPTION OF THE PRESENT INVENTION

The present invention is directed to a design related to the first type of straight arm torque rod; however it can also be adapted for use in V-shaped torque rod as well. The present invention is comprised of a male assembly and a female assembly which, when assembled together, matingly come together by insertion of an elongated end of the male assembly into an elongated end of the female assembly to create a complete torque rod. Each male and female assembly includes an outer portion and an inner portion. Each outer portion has an extended portion (an “elongated leg”) and a “top” member. Each outer portion is made of forged steel and is hollow in its entirety.

The present invention is an improvement over prior torque rods. The torque rod of the present invention is comprised of a two piece mating design which increases rigidity and reduces the number of welds. Unlike other designs this design has single piece forged ends which permits the torque rod of the present invention to take greater payloads than other designs can take.

Because different applications require different length torque rods, the present invention allows for standardized manufacture of the male and each female outer portions. The elongated legs of the outer portions may be cut by a craftsperson for the particular application of use. One additional advantage to the present invention is that the craftsperson has some flexibility in cutting the outer portions and need not cut with fine precision, or even at all, because the male portion and female portion matingly come together. In addition, the cut may be made at the time of assembly.

When mated and used in a vehicle, it is important for vehicle stability to assure that the top members are properly parallel to each other. The male assembly's elongated leg, which matingly fits inside of the female assembly's elongated leg, includes an alignment groove imprinted on the elongated leg and which runs for at least a portion of the male assembly's elongated leg along its center line. The female assembly's elongated leg includes an alignment hole. When an operator mates the assemblies such that the alignment line is visible through the alignment hole, the male section's top member and the female section's top member are aligned parallel to each other. The two piece design has an added weld alignment hole (plug or fillet hole) and alignment groove which gives the installer a visual aid to align the ends of the torque rod and provides better weld quality due to the weld filler being able to fuse better through the fillet hole.

As stated, each outer portion's top member is hollow. However, each top member is “filled” with one of several optional inner portions, with the selection of assembly based upon the particular application. Any particular torque rod may have the same or different inner portions in the two top members. Each inner portion includes a bearing assembly, which is sealed within the inner portion. Each inner portion is formed so as to allow flexibility appropriate for the particular vehicle yet is sealed so as to assure abrasives or other undesirable elements do not enter the area near the bearing so as to improve wear. The more typical inner portions are referred to here as straddle pins, ball studs, or hollow balls.

The improvements in the present invention include a steel outer cap and sealed ends which protects the inner components from dust and grime from puncturing the seal. Unlike other designs, this design includes top bearings which prevent contact between the main bearing and top outer ring. Unlike customary torque rods, the present invention includes a single unit center bearing, which increases contact patch with the radial full ball inner pin thus reducing friction and increasing the lubrication containment. The engineered thermoplastic material used provides good creep resistance, dimensional stability, high impact resistance, high molecular weight, stiffness, strength and toughness. In addition, the steel lower bearing is made of St35 steel, unlike the materials used in conventional torque rods. This provides support to a radial ball in the inner assembly and contains excessive vertical movements of the inner assembly which further provides added rigidity and a better ride. Finally another new feature is the fillet hole and alignment groove which give accurate visual indication of alignment and also help in distribution of filler material while welding. This makes the mating design very secure.

The present invention is directed towards reduced cost while providing superior performance characteristics of torque rods. The benefits of such a design include improved and less expensive installation and improved durability by allowing for customization during installation. The two-piece design is constructed using a single weld. The single weld design provides improved strength over a multiple weld design and cuts down on labor involved. The unique head housing design features inner components that give optimal articulation and reduced friction for prolonged life. The steel cap/housing containment mechanism makes bearing system more stable and provides ideal working torque.

The present invention has a full radial ball design which provides greater articulation and less internal friction which prolongs the life of the torque rod. The present invention has sealed-in lubricant which provides continuous lubrication enhancing the working of the torque rod. The containment mechanism is protected by an outer steel cap which prevents dust and grime from puncturing the seal thus protecting the inner components of the sealed ends from abrasive elements. The present invention has a top bearing made of a high performance Thermoplastic Polyurethane, which prevents the contact of the metal top ring with the main bearing. The polyurethane also improves elastic memory and hydrolytic stability over earlier designs, making the whole unit more rigid and longer lasting while providing improved performance. In the preferred embodiment, the present invention also incorporates a single unit center bearing made from polyoxymethylene, also known as POM, polyacetal or polyformaldehyde, which is an engineered thermoplastic belonging to the family of homopolymer acetal, such as Delrin 100 NC 10 TM from the DuPont Corporation. The bearing provides contact patch for the entire radial ball thus reducing friction and increasing the lubrication containment. Polyoxymethylene is used in part because it provides good creep resistance, dimensional stability, high impact resistance, high molecular weight, stiffness, strength and toughness. The present invention has a lower bearing that is made of St35 Steel and the lower bearing provides support to the radial ball and contains excessive vertical movements of the inner pin. This provides added rigidity and better ride.

Features available in the present invention include:

Male-Female Mating Design—This design provides greater rigidity and requires fewer welds compared to three piece design.

Single Piece Forged Ends—This design provides longer life and greater payloads as the single piece forged design increases structural integrity over traditional welded design.

Sealed Housing Ends—The sealed design keeps out abrasive external elements from wearing out the internal components. The housing ends are constructed with C45 high grade steel which provides yield strength of 50,000-58,000 PSI.

Full Radial Ball Inner Pin—The full radial ball provides greater articulation and less internal friction which prolongs the life of the torque rod. The Radial ball inner pins are made with 42CrMo4 steel which has yield strength of 79,700-116,000 PSI.

Sealed-in Lubrication—Sealed in grease provides continuous lubrication enhancing the working of the torque rod and providing longer life.

Outer Steel Cap—The outer steel cap which is welded to the housing prevents dust and grime from puncturing the seal thus protecting the inner components of the sealed ends from abrasive elements.

Top Bearing—The top bearing is made out a high performance Thermoplastic Polyurethane, or an equivalent, prevents the contact of metal top ring with the main bearing. It increases elastic memory and hydrolytic stability, making the whole unit more rigid and long lasting while providing optimal performance.

Single Unit Center Bearing—The present invention includes a single center bearing made from an engineered thermoplastic. The bearing provides contact patch for the entire radial ball thus reducing friction and increasing the lubrication containment. The engineered thermoplastic provides good creep resistance, dimensional stability, high impact resistance, high molecular weight, stiffness, strength and toughness

Lower Bearing—The lower bearing is made of St35 Steel or equivalent and provides support to the radial ball and contains excessive vertical movements of the inner pin. This provides added rigidity and better ride.

Lower Cap (used only in torque rod ends with a taper stud design) The lower cap is a containment mechanism for torque rod ends using the taper stud design. The lower cap is made of St3 K32 Steel or equivalent.

Fillet hole and alignment groove—The fillet and alignment groove gives the installer a visual aid to align the ends of the torque rod and provides better weld quality due to the weld filler being able to fuse better through the fillet hole.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention is directed to a torque rod comprising a hollow shaft joint assembly with a sealed internal pin assembly, where the pin has a radial ball design. As can be seen inFIG. 1, a second joint assembly with a solid shaft mates into the first joint assembly. The torque rod is prepared by cutting the shaft of the second joint to a desired length and welding the male and female assemblies. In the present invention, the “top” member and the “elongated” leg are forged as a single piece. In one embodiment, the inner pins have a radial design. In another embodiment, the pin is interfaced in the head housing with a plastic or POM collar bearing. In another embodiment, the pin and bearing are contained in the head housing with support rings typically made out of the same material. The entire construction of the head housing is covered with a dust boot, which is clamped to the housing by means of a clamping ring. When a dust boot is used, it may be used on both sides of the housing when a straddle pin is used. The dust boot may be used on one end with a clamping ring and a metal cap may be used on the other side when a taper stud is used. In another embodiment, the head housing is welded to the shaft. In another embodiment, a male and female two piece mating design may be used, and such a design may include a non-replaceable pin. When a dust boot is used, an outer steel cap may be used to cover an inner dust boot. In another embodiment, a solid shaft may be used to weld or forge the end housings with the said containment mechanism and pin instead of the male-female design. In another embodiment, the radial inner pin is replaced by a convoluted inner pin.

Referring toFIGS. 1-3,FIG. 1depicts a view of an assembled torque rod700of the present invention. Torque rod700is comprised of male assembly705and female assembly703. Male assembly705is comprised of male outer portion751and male inner portion731. Male outer portion751is further comprised of male elongated leg752and male top member753, which are forged as a single unit. Male outer portion751is made of a hardened steel and may be further coated by a rust preventer to improve longevity. Male outer portion751is hollow on the inside. Male elongated leg752is cylindrical in shape with a nominal diameter of 1.25 inches (32 mm) with typical lengths in the range of 30.0 inches to 30.5 inches. Male top member753is also cylindrical in shape with an opening at 90 degrees to that of elongated leg752, and with a nominal diameter of 3.74 inches (95 mm).

Female assembly703is comprised of female outer portion761and female inner portion732. Female outer portion761is further comprised of female elongated leg762and female top member763, which are forged as a single unit. Female outer portion761is made of hardened steel and may be further coated by a rust preventer to improve longevity. Female outer portion761is hollow on the inside. Female elongated leg762is cylindrical in shape with a nominal diameter of 1.75 inches (44.5 mm) and nominal wall thickness of 0.24 inches (6.17 mm) with typical lengths in the range of 5.90 inches tube to 8.5 inches″ center to tube end. Female top member763is also cylindrical in shape with an opening at 90 degrees to that of elongated leg762, and with a nominal diameter of 3.74 inches (95 mm). Female elongated leg762also includes alignment hole706, which is placed at a point on the center line of female elongated leg762.

FIG. 2depicts an exploded view of a portion of male assembly705, comprised of male outer portion751and male inner portion731. As shown inFIG. 2, inner portion731is of a ball stud design, but other designs may be used instead. In addition, alignment groove300is etched into male elongated leg752for later attachment to female assembly763.

FIG. 3depicts an exploded view of female assembly703when mated with male assembly705and comprised of female outer portion731and female inner portion732. Female outer portion731is further comprised of fillet hole706. When properly aligned in mating, alignment groove900is visible through fillet hole706and weld filler (or weld plug) can be applied in fillet hole706for welding with the channel serving both for alignment and improved welding purposes. As shown inFIG. 3, female inner portion732is inclusive of a ball stud design, but other designs may be used instead.

FIGS. 4-5show additional unassembled male and female assemblies with different inner portions.FIG. 4shows hollow ball620in the male assembly and straddle ball600in the female assembly.FIG. 5shows straddle ball600in the male assembly and ball stud640in the female assembly.

FIGS. 4-5also show the mating design of the torque rods. Female elongated end762receives male elongated end752. The internal diameter of female elongated end762is machined with an indentation in such a way to provide a snug fit for male elongated end752. Male elongated end752has an alignment groove900that is visible inside of fillet hole706of female elongated end762when assembled. The groove helps the installer align the shafts such that the end housings and radial pins are straight and not angled. Fillet hole706also helps as a diffuser of weld filler or weld plug and helps in distributing it for a sturdy welded joint.

FIG. 6shows an exploded view of ball stud640in a female assembly. Although shown inFIG. 6with female outer portion761, the invention also includes male outer portion751in place of female outer portion761. Female outer portion761, comprised of female top member763and female elongated leg762with fillet hole706, is made of high grade C45 steel such as SAE 1045 and, in the preferred embodiment, is of nominal diameter of approximately 3.5″, which may vary, typically by 20%, based upon the application of use.

Female outer portion761is held in place in one direction by upper cap205and dust boot204, which are attached to female outer portion761by use of ring203, washer202, and nut201. Upper cap205is typically comprised of St 3 K32 or equivalent. Dust boot204is comprised of a thermoplastic.

In the lower direction, female outer portion761is held in place by top bearing207, which rests within female outer portion761and center bearing208. Ball pin209is fit inside center bearing208and is shaped as a radial ball. And provides for rotational movement of the torque rod of the present invention. Lower bearing210encircles ball pin209and lower cap211is used to protect the lower assembly from dirt and other contaminants.

FIG. 7shows the engineering drawing showing dimensions and tolerances for one typical embodiment of the sealed interior of the torque rod design. The tables in the drawings also show the materials used for each component. Housing401is the housing made of C45 steel. It is forged and normalized to between 172-216 HB. Housing401contains ball pin402, which is made of steel 41Cr4 quenched and tempered to between 23-33 HRC. Support ring (TPC)403is made of a thermoplastic polyurethane elastomer and contains ball pin402at its top and holds down center bearing404. Center bearing404is made from an engineered thermoplastic. Center bearing404provides contact patch with ball pin402. Support ring (metal)405contains this arrangement from the other side and is made from St 35 steel. Lock ring406holds the arrangement together and washer407sits between lock ring406and dust boot408. Dust boot408covers the inner parts and protects them. Dust boot408also contains grease which provides constant lubrication for the inner components. Clamping ring409contains boot408inside ring410. Clamping ring409is made from DIN 2076 B steel or equivalent. In embodiments which have a straddle pin (pin with mounting holes on either side) two have dust boots may be used to cover the housing on either side and in other embodiments which have ball stud (pin with a taper stud with threads on one side and a full sphere on the other side) the dust boot may cover only the top and a cap will cover the bottom. Ring410is made of St3 K32 steel covers wither side of the housing and is welded on to the housing. Ring410protects dust boot408and inner components. Again in embodiments that have straddle pin have the cap on both sides and embodiments with ball stud have the cap on the taper stud or upper end only.FIGS. 8 and 9show alternative embodiments of the interior of the torque rod of the present invention.

FIG. 8shows another embodiment of the interior of the torque rod design. This figure shows a male part with straddle ball ends. The rod end is solid with a diameter of 32 mm (1¼″). This solid rod mates with the female end. Housing501which includes the rod is made of normalized C45 steel hardened to 172-216 HB. Housing501contains ball pin502, which is made of steel 41Cr4 quenched and tempered to between 23-33 HRC. Support ring (TPC)503made of a thermoplastic polyurethane elastomer and contains ball pin502at its top and holds down bearing504, which is made from an engineered thermoplastic. Center bearing504provides contact patch with the ball pin502. Support ring (metal)505contains this arrangement from the other side and is made from St 35 steel. Lock ring segment506holds the arrangement together and washer507sits between lock ring segment506and dust boot508. Dust boot508covers the inner parts and protects them. Dust boot508also contains grease which provides constant lubrication for the inner components. In embodiments which have a straddle pin (pin with mounting holes on either side) two dust boots may be used to cover the housing on either side and in other embodiments which have ball stud (pin with a taper stud with threads on one side and a full sphere on the other side) dust boot508covers only the top and a cap will cover the bottom. Ring510, made of St3 K32 steel covers either side of the housing and is welded on to the housing. Clamping ring509contains boot508inside ring510. Clamping ring509is made from DIN 2076 B steel or equivalent. Ring510protects dust boot508and inner components. Again, in embodiments that have straddle pin have the cap on both sides and embodiments with ball stud have the cap on the taper stud or upper end only.

FIG. 9shows another embodiment of the torque rod design. This figure shows a male part with ball stud end. The rod end is solid with a diameter of 32 mm (1¼″). This solid rod mates with the female end. Housing601includes the rod and is made of normalized C45 steel hardened to 172-216 HB. Housing601contains ball pin602, which is made of steel 42CrMo4 and is quenched and tempered to between 26-33 HRC. Ball pin602has a taper stud with appropriate threads cut on the end. Ball pin602is used with appropriate hardware such as washer610and elastic lock nut611. Support ring (TPU)603made of a thermoplastic polyurethane elastomer and contains ball pin602at the top and holds down bearing604, which is made from an engineered thermoplastic. Bearing604provides contact patch with ball pin602. Support ring (metal)605contains the arrangement described from the bottom and is made from St 52 steel. Cap606made of St3 K32 steel covers the arrangement from the bottom and seals ball pin602inside housing601. Cap606also provides protection against vertical movements of ball pin602and shields the inner components from abrasives particles. Dust boot607covers the inner parts and protects them. Dust boot607also contains grease which provides constant lubrication for the inner components. Clamping ring608, made of DIN 2076B, locks the ball pin602in housing601and holds it down. Ring609made of St3 K32 steel and covers the top of housing601and is welded on to housing601. Ring609protects dust boot607and inner components.

FIG. 10shows another embodiment of the torque rod design. This figure shows a female part with hollow ball ends. The rod end is a receiver end with a fillet hole. This hollow end mates with the male end. Housing801is made of normalized C45 steel hardened to 172-216 HB. Housing801contains hollow ball802which is made of steel 41 Cr4 hardened to between 23-33 HB. Hollow ball802has a hole drilled through it (bolt hole811) and the diameter of the hole can be as per the size of the mounting bolt required for a particular application. Support803made of a thermoplastic polyurethane elastomer, contains the hollow ball802at its top and holds down center bearing804which is made from Polyoxymethylene or POM. Center bearing804provides contact patch with the full radial ball. Support ring805contains this arrangement from the other side and is made from St 35 steel. Lock ring806holds the arrangement together and washer807sits between the lock ring and dust boot808. Dust boot808covers the inner parts and protects them. Dust boot808also contains grease, which provides constant lubrication for the inner components. Dust boot808also covers the bottom similarly. Washer807is made from hardened steel and sits between lock ring806and dust boot808. In embodiments which have a straddle pin (pin with mounting holes on either side) two dust boots may be used to cover the housing on either side and in other embodiments which have a ball stud (pin with a taper stud with threads on one side and a full sphere on the other side) dust boot808covers only the top and a cap covers the bottom. A Washer809is made from hardened steel and sits between lock ring806and dust boot808. Cap/ring810made of St3 K32 steel covers either side of the housing and is welded on to the housing. This ring protects the dust boot and inner components. Again in embodiments that have straddle pin have the cap on both sides and embodiments with ball stud have the cap on the taper stud or upper end only.

FIG. 11shows a perspective view of an installed torque rod. InFIG. 11, torque rod700is attached at one end to differential housing310and to frame rail320of the vehicle's chassis. Because of the perspective of the figure, the torque rod may appear asymmetrical, and the actual symmetry and shape of the torque rod is better seen inFIGS. 1-3.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above process, in the described product, and in the construction set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrated and not in a limiting sense.