Patent Application
20050239560
The present invention relates in general to rotational connection joints and more specifically to a device and method of manufacturing for a universal joint.
Universal joints of the double cardan type are known which are used to accommodate maximum drive line deflections up to approximately 25°. The double cardan joint is generally effective up to approximately 12° of drive line deflection at typical operating conditions. One disadvantage of the double cardan joint is that it is susceptible to increased wear and centering mechanism free play when operated at higher deflection angles. Another disadvantage of the double cardan joint is that it is also susceptible to damage by infiltration of dirt, etc. because the centering mechanisms of these joints are generally not sealed to prevent exposure to environmental conditions.
An improvement to the double cardan joint includes a universal joint having two connected constant velocity joints. An example of this is provided in U.S. Pat. No. 3,857,256 to Girguis, issued Dec. 31, 1974. A similar joint design including seals to prevent dirt or environmental contamination of the constant velocity joints is provided in U.S. Pat. No. 3,593,541 to Kuroda, issued Jul. 20, 1971. These universal joint designs provide multiple constant velocity joints within an outer bearing race. Each constant velocity joint is fixed to either one of an input or an output shaft of the universal joint. Either the ends of the shaft or connections to the shaft are joined at about the center of the universal joint to evenly distribute the total displacement between both constant velocity joint assemblies of the universal joint. Rigid centering mechanism halves are provided to approximately divide the total displacement angle of the universal joint between both constant velocity joints. The rigid centering mechanism halves rely on proper alignment of the various universal joint components and generally provide only point contact between curved surfaces when the universal joints are in their displaced conditions.
In one form, the present teachings provide a universal joint comprising a first shaft having a first axially extending member and a distal end. A first constant velocity joint is fixedly connected to the first axially extending member, the first constant velocity joint including a first plurality of spherical balls. A second shaft has a second axially extending member and a second shaft distal end. A second constant velocity joint is fixedly connected to the second axially extending member, the second constant velocity joint including a second plurality of spherical balls. A centering mechanism operably joins the first axially extending member to the second axially extending member, the centering mechanism including: a semi-spherical female member connectable to the first shaft distal end; and a male member having a semi-spherical portion rotatably receivable by the female member. The male member is slidably coupled to the second shaft.
In another form, the present teachings provide a universal joint operable to transmit a driving torque having a first assembly including a first constant velocity joint fixedly connected to a first longitudinal shaft. A second assembly includes a second constant velocity joint fixedly connected to a second longitudinal shaft. A bearing race is operably engaged with both the first and second constant velocity joints, the bearing race operable to transmit the driving torque from the first constant velocity joint to the second constant velocity joint. A rotatable mechanism operably joins the first longitudinal shaft to the second longitudinal shaft, the rotatable mechanism including: a first bearing member connectable to the first longitudinal shaft, the first bearing member including a semi-spherical concave bearing surface; and a second bearing member having a flat contact end and a convex semi-spherical portion rotatably receivable by the concave bearing surface. A biasing element is disposed between the flat contact end and the second shaft operable to axially displace the second bearing member relative to the second shaft.
The features, functions, and advantages can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Referring generally to
Semi-spherical ball engagement surface 34a permits spherical balls 26 of first CV joint 15 to rotate in contact with semi-spherical ball engagement surface 34a thus permitting first CV joint 15 to rotate through an arc “A” about a CV joint axis of rotation “B”. CV joint axis of rotation B is positioned on a first CV joint centerline “C”. Second CV joint 20 is similarly rotatably mounted.
Centering mechanism 22 can further include an adapter 35 having a male end 36 which can be slidably fit or press fit into a receiving aperture 37 of longitudinal shaft 14. Male end 36 can be slid into receiving aperture 37 until adapter 35 engages shaft distal end 16. Adapter 35 can also include a female end 38 which may be adapted to receive a concave bearing member 39. Centering mechanism 22 can also include an adapter 40 having a mating end 41 which may be slidably fit or press fit into a receiving aperture 42 of longitudinal shaft 19. Adapter 40 can be engaged with longitudinal shaft 19 until adapter 40 contacts shaft distal end 21 of longitudinal shaft 19. A ball joint 44 can be slidingly engaged on a bearing end 43 of adapter 40 such that a convex surface of ball joint 44 contacts a concave mating surface of concave bearing member 39. When first CV joint 15 and second CV joint 20 rotate in response to a deflection load, centering mechanism 22 can displace in a centering displacement path represented by arrows “D”. In a non-displaced condition for universal joint 10, longitudinal shaft 14 and longitudinal shaft 19 can both align coaxially along a longitudinal axis 45 of universal joint 10.
To prevent environmental contaminants from entering universal joint 10, a seal 46 having a shaft engagement end 48 can be secured to longitudinal shaft 14 using a clamp 50, for example. A distal end 52 of seal 46 can be retained in a crimped end 54 of a seal cup 56. Seal cup 56 can be matingly engaged with a first end 57 of outer bearing race 24. Similarly, a seal 58 having a shaft engagement end 60 can be secured to longitudinal shaft 19 using a clamp 62, for example. A distal end 64 of seal 58 can be retained within a crimped end 66 of a seal cup 68. Seal cup 68 can be engaged with a second end 69 of outer bearing race 24 using a cupped end 70 of seal cup 68. Material for seal 46 and seal 58 may be an elastomeric material known in the art, for example a compounded rubber.
Referring generally to
As generally seen in
As more specifically shown in reference to
Referring generally to
Similarly, longitudinal shaft 19 can rotate such that longitudinal axis 89 is displaced below longitudinal axis 45. Second CV joint 20 rotates clockwise about CV joint axis of rotation “J” between the second CV joint centerline “E” and a rotated centerline position “K”. Second CV joint 20 therefore rotates relative to longitudinal axis 89. Second CV joint 20 centerline position “K” is rotated approximately half the angular rotation of angle θ. Flange 13 and connector fitting 18 both generally displace in a downward direction in the example shown in
Angle α can range between 0° up to about 7.5° in normal operating conditions, including high speed approximately 128.7 km/hr (80 mph) continuous driving operation. Angle α can typically range up to approximately 150 at a maximum deflection. The maximum deflection accommodates vehicle maximum suspension deflections permitting large road surface deflections of limited duration, off road vehicle operation or lifting the vehicle during maintenance. The maximum possible displaced condition for angle α can be determined when, for example, seal 46 compresses completely and longitudinal shaft 14 contacts crimped end 54 of seal cup 56 or alternately defined when adapter 35 contacts an internal surface of outer bearing race 24.
Longitudinal shaft 19 rotates in conjunction with oppositely directed longitudinal shaft 14 to form angle θ with longitudinal axis 45. A maximum deflection for longitudinal shaft 19 is substantially equal to the maximum deflection of longitudinal shaft 14, such that angle θ substantially equals angle α. The maximum deflection for longitudinal shaft 19 can be similarly limited by contact between seal 58 and crimped end 66 of seal cup 68 or contact between adapter 35 and the internal surface of outer bearing race 24.
For normal operating conditions the total deflection for universal joint 10 can be determined by adding angle α and angle θ. This results in an approximate 150 deflection range for normal operating conditions and a maximum deflection of approximately 300.
Referring again to
Referring again to
Materials for universal joint 10 are commonly known for universal joint application. Exemplary materials include 5120 steel, carburized and hardened for the cages 28 and 29, the inner bearing races 30,31, the outer bearing race 24, the ball joint 44 and the concave bearing member 39. Induction hardened steel can be used for the flange 13, the connector fitting 18, the longitudinal shafts 14 and 19 and the adapters 35 and 40. Spherical balls 26 and 27 can be of high carbon steel, through-hardened and ground. These materials are exemplary only and can be replaced by materials as known to a person of skill in the art. A lubricant such as a high quality bearing grease is commonly inserted into universal joint 10 before seals 46,58 are clamped by clamps 50,62, respectively.
A universal joint of the present invention offers several advantages. By combining continuous velocity joints into a single universal joint a maximum deflection of about 30° can be achieved between an input and an output of universal joint 10. By biasing a ball joint of a centering mechanism of the present invention, the ball joint is maintained in continuous contact over a greater surface area of a corresponding concave bearing member of the centering mechanism. This maintains alignment between components of the universal joint.
While various preferred embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the inventive concept. The examples illustrate the invention and are not intended to limit it. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.
