Axle and spindle for heavy-duty vehicle and method

An axle spindle for a heavy-duty vehicle, the axle spindle for receiving at least one bearing assembly to support a hub for rotation relative to the axle spindle, the axle spindle comprising:

• a tubular first cylindrical section having a portion with a first outer diameter, the first cylindrical section having an end surface connectable with an axle central tube;
• a tubular second cylindrical section integrally and coaxially formed with and extending in a direction away from the first cylindrical section, the second cylindrical section having a second outer diameter less than the first diameter of the first cylindrical section, the second cylindrical section having at least one bearing support surface with a bearing support diameter to receive and support a bearing assembly;
• a tubular transition section integrally and coaxially formed with and located between the first cylindrical section and the second cylindrical section;
• an annular shoulder portion integrally and coaxially formed in an end segment of the tubular transition section adjacent the second cylindrical section, the shoulder portion having an annular shoulder surface for engaging an annular surface of the bearing assembly;
• an annular profile located in the shoulder portion between the annular shoulder surface and the bearing support surface, the annular profile defined by a surface having a third diameter that is not less than the bearing support diameter of the bearing support surface;
• and
• the annular profile defined by a first annular surface with a first radius taken in a plane containing a longitudinal central axis of the axle spindle, the first annular surface located between the annular shoulder surface and the bearing support surface, a second annular surface with a second radius taken in the plane containing the longitudinal central axis of the axle spindle, the second annular surface being located between the first annular surface and the bearing support surface, the second radius of the second annular surface being greater than the first radius of the first annular surface.

An axle spindle for a heavy-duty vehicle wheel end, the axle spindle for receiving at least one bearing assembly for supporting a hub for rotation, the axle spindle comprising:

• a tubular first cylindrical section having a portion with a first outer diameter, the first cylindrical section having an end surface connectable with an axle central tube;
• a tubular second cylindrical section integrally and coaxially formed with and extending in a direction away from the first cylindrical section, the second cylindrical section having a second outer diameter less than the first diameter of the first cylindrical section, the second cylindrical section having at least one bearing support surface with a bearing support diameter to receive and support a bearing assembly;
• a tubular transition section integrally and coaxially formed with and located between the first cylindrical section and the second cylindrical section;
• an annular shoulder portion integrally and coaxially formed in an end segment of the transition section adjacent the second cylindrical section, the shoulder portion having an annular shoulder surface for engaging an annular surface of the bearing assembly;
• and
• an annular profile located in the shoulder portion between the annular shoulder surface and the at least one bearing support surface, the annular profile defined by a surface having a third diameter that is not less than the bearing support diameter of the bearing support surface;
• wherein the annular profile has a first radiused surface with a first radius located between the annular shoulder surface and the at least one bearing support surface, a second radiused surface with a second radius located between the first radiused surface and the at least one bearing support surface;
• wherein the second radius of the second radiused surface is greater than the first radius of the first radiused surface;
• and
• wherein the ratio of the second radius to the first radius is at least 5:1.

An axle assembly for a heavy-duty vehicle, the axle assembly comprising:

• a central tube;
• an axle spindle for receiving at least one bearing assembly to support a hub for rotation relative to the axle spindle, the axle spindle fixed to the central tube, the axle spindle comprising:
• a tubular first cylindrical section having a portion with a first outer diameter, an end surface of the first cylindrical section being connectable with the central tube of the axle spindle;
• a tubular second cylindrical section integrally formed with and extending in a direction away from the first cylindrical section, the second cylindrical section having at least one bearing support surface for receiving and supporting a bearing assembly of the hub and having a second outer diameter less than the first outer diameter;
• a tubular transition section integrally formed with and located between the tubular first cylindrical section and the tubular second cylindrical section;
• and
• a chucking land pad formed in the tubular transition section, the chucking land pad for engagement with a tool to induce relative rotational movement between the central tube and the axle spindle during a friction weld operation;
• an annular shoulder portion integrally and coaxially formed in the transition section adjacent the second cylindrical section, the shoulder portion having an annular shoulder surface for engaging an annular surface of the bearing assembly;
• and
• the tubular transition section having a rate of change in section modulus taken at an axial location between adjacent sections spaced apart in 0.050 inch increments from the shoulder surface in a direction towards the end surface of the first cylindrical section varies no more than 14% for every rate of change in section modulus.

An axle spindle for a heavy-duty vehicle wheel end, the axle spindle for receiving at least one bearing assembly for supporting a hub for rotation, the axle spindle comprising:

• a tubular first cylindrical section having a portion with a first outer diameter, the first cylindrical section having an end surface connectable with an axle central tube;
• a tubular second cylindrical section integrally and coaxially formed with and extending in a direction away from the first cylindrical section, the second cylindrical section having a second outer diameter less than the first diameter of the first cylindrical section, the second cylindrical section having at least one bearing support surface with a bearing support diameter to receive and support a bearing assembly;
• a tubular transition section integrally and coaxially formed with and located between the first cylindrical section and the second cylindrical section;
• an annular shoulder portion integrally and coaxially formed in an end segment of the transition section adjacent the second cylindrical section, the shoulder portion having an annular shoulder surface for engaging an annular surface of the bearing assembly;
• and
• an annular profile located in the shoulder portion between the annular shoulder surface and the at least one bearing support surface, the annular profile defined by a surface having a third diameter that is not less than the bearing support diameter of the bearing support surface;
• wherein a rate of change in section modulus taken at an axial location between adjacent sections spaced apart in 0.050 inch increments from the shoulder surface in a direction towards the end surface of the tubular first cylindrical varies no more than 10% for every rate of change in section modulus.

A method of making an axle spindle for a heavy-duty vehicle, the method comprising the steps of:

• providing a hollow member;
• forming a first cylindrical section on the hollow member to have a portion with a first outer diameter;
• forming a second cylindrical section on the hollow member integrally with and extending in a direction away from the first cylindrical section, the second cylindrical section having a second outer diameter less than the first outer diameter;
• forming a transition section on the hollow member integrally with, and located between, the first cylindrical section and the second cylindrical section, the transition section tapering from the first cylindrical section to the second cylindrical section;
• forming a bearing support surface on the second cylindrical section, the bearing support surface for receiving and supporting a bearing and having a second diameter less than the first diameter;
• integrally forming an annular shoulder portion in the transition section adjacent the bearing support surface and having an annular shoulder surface;
• and
• forming at least one surface defining an annular profile in the annular shoulder portion between the bearing support surface and the annular shoulder surface, whereby the annular profile is defined by a third diameter that is not less than the second diameter of the bearing support surface;
• forming a chucking land pad on the transition section;
• machining away the chucking land pad to form a finished transition section.