Drive unit for wheel and assembly method for the same

• US 6,851,866 B2
• Filed: 07/31/2001
• Issued: 02/08/2005
• Est. Priority Date: 07/31/2000
• Status: Expired due to Term

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Kayama, Shigeoki, Ouchi, Hideo
• Primary Examiner(s): SICONOLFI, ROBERT
• Application Number:
  US09/917,859
• Publication Number:
  US 20020044706A1
• Time in Patent Office: 1,288 Days
• Field of Search: 384/544, 384/589, 384/584, 403/359.1, 403/359.5, 403/359.6, 464/160, 464/906
• US Class Current: 384/584
• CPC Class Codes: B60B 27/00 Hubs non-metallic B60B5/00; of high resiliency B60B9/00
• CPC Class Codes: F16C 19/184 in O-arrangement
• CPC Class Codes: F16C 2326/02 Wheel hubs or castors in general B60B
• CPC Class Codes: F16C 35/063 Fixing them on the shaft with interposition of an element F16C35/07
• CPC Class Codes: F16D 1/116 the interengaging parts including a continuous or interrupted circumferential groove in the surface of one of the coupling parts circlips for retaining hubs on shafts F16B21/18
• CPC Class Codes: F16D 2001/103 the torque is transmitted via splined connections
• CPC Class Codes: F16D 2003/22326 Attachments to the outer joint member, i.e. attachments to the exterior of the outer joint member or to the shaft of the outer joint member
• CPC Class Codes: F16D 3/223 the rolling members being guided in grooves in both coupling parts

Abstract

A combination of a constant-velocity joint and an axle unit for wheel-drive which comprises an outer race having an outer-ring raceway and being not rotatable even during use, a hub having an installation flange for supporting the wheel near the outside end, a first spline section and an inner-ring raceway near the inside end facing the outer-ring raceway, a drive member having a second spline section facing the first spline section, and a housing section forming an outer ring of the constant velocity joint, a plurality of rolling bodies between the outer-ring raceway and inner-ring raceway, the hub being engaged with the drive member by way of a spline connection with a pitch circle, and a coupling member adapted to freely deform elastically in the radial direction and located between and engaged with the first engagement section and the second engagement section so as to position the hub and drive member in the axial direction, wherein the clearance width in the circumferential direction on the pitch circle is controlled within the range of 0.001 mm to 0.10 mm.

Claims

1. A method of assembling a wheel drive unit comprising a rolling-bearing unit for supporting a wheel, a constant-velocity joint unit and a coupling member, to be connected to a differential gear having an output section, the constant-velocity joint unit comprising a first constant-velocity joint having an output section and an input section, the input section being connected to the output section of the differential gear, a transmission shaft having an output end and an input end, the input end of the transmission shaft being connected to the output section of the first constant-velocity joint, and a second constant-velocity joint having an input section connected to the output end of the transmission shaft, the rolling-bearing unit for supporting the wheel comprising an outer race having an outside end and being not rotatable even during use, a hub having an inside end and an outside end and a plurality of rolling bodies, the outer race having an inner peripheral surface formed with an outer-ring raceway thereon, the hub having an outer peripheral surface and comprising an installation flange for supporting the wheel, the installation flange being formed on the outer peripheral surface of the hub near the outside end on a portion that protrudes outward from the outside end of the outer race toward the outside, an inner-ring raceway that is formed near the inside end of the hub directly on the hub or by way of an inner race, such that the inner-ring raceway faces the outer-ring raceway, and a first fitting peripheral surface formed with a first spline section, the rolling bodies being rotatably located between the outer-ring raceway and the inner-ring raceway, the second constant-velocity joint comprising a second fitting peripheral surface located at an outside end thereof where the second spline section is engaged with the first spline section through a spline connection, and a housing section formed on an inside end thereof so as to function as an outer ring of the second constant-velocity joint, the coupling member being adapted to deform elastically in the radial direction and located between and engaged with the first engagement section formed on the peripheral surface of the hub and the second engagement section formed on the peripheral surface of the second constant-velocity joint so as to position the hub and second constant-velocity joint in the axial direction, wherein the spline connection between the first and second spline sections engaged with each other is regulated in a clearance angle, wherein at least one of the transmission shaft and the second constant velocity joint including the housing section has an outer peripheral surface formed with an engagement portion, so that when the second constant velocity joint is spine-connected to a rolling bearing unit for supporting a wheel, at least one of the transmission shaft and the second constant velocity is engaged with a robot arm to prevent the robot arm from being axially displaced with reference to the at least one of the transmission shaft and the second constant velocity joint,

the method comprising the steps of:

grasping the engagement portion formed on the outer peripheral surface of the at least one of the transmission shaft and the second constant-velocity joint, supporting the rolling bearing unit for drive wheel so as not to be displaced in the retracting direction following the displacement of the robot arm, and then in this state displacing the robot arm, and making the second constant-velocity joint engaged with the rolling bearing unit for supporting the wheel through spline connection, wherein in the state where the second constant velocity joint is engaged with the rolling bearing unit for supporting the wheel through spline connection, coupling the second constant velocity joint to the rolling bearing unit for wheel support with a coupling member based on the elastic deformation thereof, and then using the robot arm to apply a force smaller than the strength of the coupling member in the direction to separate the second constant-velocity joint from the rolling bearing unit for wheel support, so as to check whether the coupling with the coupling member is securely conducted.