Two-piece vertical control arm bushing

A bushing, for use with a control arm, has first and second mating segments that can be mated and assembled to form a central portion to be received within a circular opening in the control arm and the central portion has an outer diameter corresponding to the diameter of the circular opening. Each segment includes a cap or head portion having a diameter dimensioned to abut against one of the surfaces of the control arm and has a central bore. A bushing sleeve has a length equal to a axial length of the assembled bushing and an outer diameter incrementally greater than the diameter of the central bore so that the sleeve can be press fit within the bore to immobilize the segments when they are in contact with the control arm and become resistant to separation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to automotive suspension systems and, more specifically, to a two-piece vertical control arm bushing for a vehicle control arm assembly.

2. Description of the Prior Art

Front and rear suspensions of numerous automotive vehicles typically include a control arm. Vehicles equipped with control arms are used in conjunction with the suspensions of the vehicles in order to manage the motions of the wheels relative to the motions of the vehicle body.

Each control arm assembly typically includes the control arm and control arm bushings that are provided within spaced apertures in the control arm. Each of the control arm bushings is typically fabricated from rubber and is press-fit into a respective aperture in the control arm using an arbor press or other suitable device.

Each of the control arm bushings is typically sized to protrude slightly outwardly from each end of the aperture within which it resides. Inserted into each of the control arm bushings is a metallic tubular insert or sleeve that has a bore for receiving a pin or bolt for interconnecting the bushing and the control arm assembly to front wheel suspension components.

Over extended periods of time, factory-installed rubber control arm bushings used for cars, trucks and sport utility vehicles (SUV) deteriorate as does vehicle performance. For example, torque forces imposed on the vehicle during high-speed cornering or during travel over uneven terrain compresses the rubber bushings to the extent that the rubber may become permanently deformed. Permanent deformation of the bushing can result in loss of alignment (i.e., caster and camber) of the front wheels of the vehicle. In addition, permanent deformation of the rubber bushing can result in loss of steering response and reduced vehicle control that affects the overall safety of the vehicle.

Deterioration of the rubber bushings can also occur due to exposures to oils, road salt, chemicals and other corrosive substances as well as exposure to atmospheric contaminants such as ozone and smog which can attack and degrade the rubber over time. Furthermore, rubber is known to shrink and harden over time due to breakdown of polymers in the rubber. The deleterious effects on vehicle performance as a result of worn, damaged or hardened control arm bushings is even more pronounced when vehicles are used under extreme conditions such as in off-road driving and during competition such as racing.

Once control arm bushings become worn, the entire control arm assembly is frequently removed from the vehicle and replaced with a new control arm assembly. Typically, the new control arm assembly also includes control arm bushings manufactured of rubber and are, therefore, subject to the same deleterious affects of the original rubber bushings. However, the metallic control arm itself is typically undamaged and can be re-used once fitted with new control arm bushings. As may be appreciated, replacing the entire control arm assembly as opposed to only replacing the control arm bushings results in significantly increased repair costs.

There exists a need, therefore, for control arm bushings that can be used as replacements for worn rubber control arm bushings. Furthermore, there exists a need for control arm bushings that can be customized for use with numerous vehicles and that can withstand the weight and torque forces that are known to degrade factory-installed rubber bushings. Equally importantly, there exists a need for a control arm bushing that can be easily, quickly and efficiently installed without the need for replacing the entire control arm assembly to significantly reduce replacement service costs.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a vertical control arm bushing that overcomes the disadvantages of prior art bushings.

It is another object of the invention to provide a two-piece vertical control arm bushing that is simple in construction and economical to manufacture.

It is still another object of the invention to provide a two-piece vertical control arm bushing as in the previous objects that can be used with OEM control arm assemblies and used as after market control arm bushings to replace damaged bushings.

It is yet another object of the invention to provide a two-piece vertical control arm bushing that can be customized to be used with numerous vehicle control arms.

It is a further object of the invention to provide a two-piece vertical control bushing that is easy to assemble and does not require high pressure presses to press fit the bushings within associated openings within the control arm.

It is still a further object of the invention to provide a two-piece control arm bushing as in the previous objects that reduces the cost of replacement of worn or damaged bushings.

In order to achieve the above objects as well as others that will become evident hereinafter, a bushing in accordance with the present invention, for use with a control arm having upper and lower surfaces and a circular opening defining a vertical axis and a diameter De, comprises first and second mating segments defining an axis when mated and assembled and an outer diameter substantially corresponding to the diameter De. Each segment includes a cap or head portion dimensioned to abut against another one of said upper and lower surfaces of said control arm and having a central bore having a predetermined diameter. A bushing sleeve is provided that has a length substantially equal to the fully mated bushing along the vertical axis and an outer diameter incrementally greater than said predetermined diameter to allow said bushing sleeve to be inserted through said central bore in a press fit relationship in order to maintain said mating segments in assembled condition. The two segments of the two piece vertical control arm bushing are inserted into the circular opening from opposing or opposite sides of the control arm and coaxially aligned prior to being mated. After the segments have been mated the bushing sleeve is inserted through the central bore. Simple shop tools can be used to assemble the bushing.

DETAILED DESCRIPTION

Referring now specifically to the figures, in which identical or similar parts designated by the same reference numerals throughout, and first referring toFIG.1, a prior art control arm is generally designated by the reference numeral10.

The control arm assembly10is generally T-shaped as viewed inFIG.1, having free end portions12,14and16. A ball joint assembly18is shown mounted on or supported by the portion12that includes an upwardly projecting stem20commonly used to secure the control arm assembly10to a suspension component of a vehicle.

Provided at the portion14is a cylindrical front or forward tubular member22that defines a generally horizontal axis AHand houses a front bushing24that is received and supported by the cylindrical front or forward tubular member22. The axis of the front bushing24is generally coextensive with the horizontal axis AH.

The other end portion16forms a rear or back end26having upper and lower surfaces, as shown, and a circular opening28that defines a substantially vertical axis AV. Housed within and supported by the rear or back end26is a vertical rear bushing30that defines an axis that is coextensive with the vertical axis AVof the circular opening28.

During normal operation of the vehicle, the control arm portion12, that carries the ball joint assembly18, moves upwardly and downwardly generally along directions represented by the arrow32. It will be appreciated that as the portion12moves up and down more extensively than the vertical movements of the portions14,16the associated bushings24and30will be exposed to stresses including compressions and stretching. Since the movements of the front or forward portion14will be essentially about the horizontal axis H the front bushing24may be somewhat stressed but much less so than the rear vertical bushing30. It is clear that rocking or pivoting movements of the control arm portion16while the central portion of the rear bushing30remains substantially vertical this will cause significant stresses and flexing of the rubber material of which the rear bushing is formed. While some efforts have been made to prevent premature deterioration of the rear bushing30due to such constant stresses, the bushing30is still exposed to significant stresses that cause the material to break down and deteriorate. Shown inFIG.1are slits or openings34as one proposed solution designed to reduce the amount of stresses applied to the rubber material when the portion16rocks from side to side, as viewed inFIG.1, while the central part of the bushing30remains substantially vertical. Therefore, it is normally not a question of whether the rear bushings will ultimately deteriorate and fail but when or how quickly this will occur. Replacing the bushing30when it fails with a similar bushing will extend the life of the control arm assembly but the replacement bushing will also, in time, deteriorate and fail. Each time that a bushing, including an OEM bushing, fails it must be removed from the opening28and replaced by a new bushing. However, these bushings are press fit under significant compression forces and replacement of a failed bushing and replacement with a new bushing is not always simple and, frequently, if not always, requires special tools such as high power presses. This increases the time and labor charges for the owner of the vehicle.

Referring toFIG.2, a new vertical control arm bushing in accordance with the invention is shown and designated by the reference numeral36. The bushing36, as viewed inFIG.2, includes an upper female segment38. However, it will be appreciated that relative positional designations are not critical and the female segment38can also be positioned below the control arm and, therefore, be the lower segment.

Referring toFIGS.3-5, the female segment38includes an annular portion40that has an outside diameter Doand a chamber C with an inner diameter Di(FIG.3). Provided at one end of the annular portion40is a head or cap portion42that has an outer diameter Dtand a cylindrical opening or bore44, the segment38having an overall height H (FIG.3). The head or cap portion42includes an inclined surface46. The chamber C with internal diameter Disomewhat extends into the head or cap portion42, as shown inFIGS.3and5, that provides an overall axial length or height for the inner chamber C of h (FIG.3).

Referring toFIGS.6-8, the lower male segment48also has an annular portion50that has an outer diameter doand an internal diameter dias viewed inFIGS.6and7. The male segment48also includes a head or cap portion52with an outer diameter dtand a cylindrical opening, channel or bore54, and also formed with an inclined surface56.

Referring toFIGS.9and10a bushing or sleeve insert58is in the shape of a tubular member preferably provided with chamfered edges at both axial ends thereof. The bushing or sleeve58has an external diameter d and an internal diameter d′.

It will be noted from the dimensions of the two segments38and48that the outer diameter doof the segment48is substantially equal to the diameter diof the upper segment38. When coaxially aligned with the circular opening28on opposite sides of the portion16to be aligned coaxially with the vertical axis AVthe annular portion50can be inserted into or received within the annular portion40of the upper segment38substantially the full axial height h of the interior cavity or chamber C. The axial length or height of the chamber C in the upper portion is slightly greater than the axial length h′ so that the entire annular portion50can be received within the interior cavity or chamber C of the upper segment with maximum penetration to insure minimum spacing between the heads or caps42,52and reliable contact of the heads or caps with the control arm. This can be achieved with simple shop tools readily available in a shop or service station including a clamp, hammer or the like.

Once the upper and lower segments are fully mated the bushing sleeve58is inserted into the cylindrical opening or bore54. The outer diameter d of the sleeve58is selected to be somewhat greater than the inside diameter of the bores or channels44and54so that a press fit is created when the sleeve is inserted into the two segments. The axial1length of the sleeve58is selected to be equal to the axial length or height H of the segment38and the axial thickness of the head or cap52of the segment. In the example shown, the axial length or height H of the upper segment38is equal to H or 1.770″ (FIG.3). Once fully mated, the annular portion50is fully received within the cavity or chamber C of the upper segment38. The head or cap portions42,52abut against the opposing surfaces of the control arm portion16. The length of the sleeve58is, therefore, selected to be 2.47″ which is the sum of the height H or 1.770″ of the segment38and the axial thickness of the head or cap portion52, shown to be 0.7″, for a total of 2.47″. The chamfered axial ends of the bushing sleeve58facilitate insertion of the sleeve without damage to the internal surface of the segments38,48.

It will be evident that the same two-piece bushing construction can be used in connection with numerous size and style control arms by selecting suitable outer diameters Doof the annular portion40to be compatible with the circular or cylindrical openings28in the control arm and by selecting the diameter d′ to accommodate the different bolts or pins that extend through the bushing for attachment to the suspension components.

The upper or female and the lower male segments can be made from any suitable material commonly used for manufacturing bushings, such as rubber, or different formulations thereof, and the bushing sleeve58is typically formed of steel. The diameters of the cap portions42,52are selected to provide annular surfaces adequate to abut against the upper and lower surfaces of the control arm. In the illustrated example, with Dtequal to 3.475″ and the outer diameter Doequal to 2.913″ and the head or cap portion42has a diameter equal to 3.475″, so that the annular dimension of the overhang or portion that abuts the surface of the control arm portion16is approximately equal 0.562″. This number is not critical and may be modified to suit a particular control arm.

It will be evident to those skilled in the art that the two-piece vertical control arm bushing in accordance with the present invention provides a simple, inexpensive, easy-to-install vertical control arm bushing that can be installed with tools conventionally found in service stations and without the need of heavy duty presses.