Patent Description:
<CIT> discloses a motion control apparatus including a case including a planar annular disc and an annular wall extending from the planar annular disc and having a free end, an output, a bearing rotatably mounting the output to the case about an axis and within the annular wall extending axially from the planar annular disc, and a drive station mounted to the case and rotating the output, wherein the case further includes an enclosure having a panel connected to the annular wall and extending radially outward opposite to the output, a top and a lower opening defined by the panel opposite to the top, with the drive station extending in the lower opening and rotatably engaging with the output.

With the introduction of ring drives into the market place, there is a continuing need for motion control apparatus which is modular in design to provide flexibility in application, as well as being stronger and easier to manufacture.

This need and other problems in the field of motion control apparatus are solved by providing a motion control apparatus according to claim <NUM>. In some embodiments, a sealed rotary table includes a bearing rotatably mounting an output to a case about an axis and within an annular wall of the case, and a drive station mounted to the case and rotating the output. The output includes a cylindrical flange having outer and inner diameters, with a first annular seal located between the case and the inner diameter of the output, and with a second annular seal located between the annular wall of the case and the outer diameter of the output.

A case, including a planar annular disc and the annular wall extending axially from the planar annular disc, further includes an enclosure having a panel integrally connected to the annular wall and extending radially outward opposite to the output, a top integrally formed with the panel, and a lower opening defined by the panel. The panel, the top and the lower opening have cross sections perpendicular to the axis which are U-shaped. The annular wall includes a side opening corresponding to the enclosure, with the planar annular disc including an arcuate cutout corresponding to the enclosure and the side opening, and with the planar annular disc, the annular wall and the enclosure being integrally formed as a single piece part.

In a preferred embodiment, a drive station includes a housing including an annular end and an annular sleeve extending parallel to the axis from the annular end and terminating in a sleeve end at a sleeve axial extent from the annular end. A rotor is rotatably mounted inside the annular sleeve and terminating in a rotor axial extent from the annular end, with the rotor axial extent being less than the sleeve axial extent. An annular end cap is secured to the sleeve end. A rotor bearing rotatably mounts the rotor inside the annular end cap at a bearing axial extent from the annular end less than the sleeve axial extent and generally equal to or less than the rotor axial extent. An encoder, received in the annular end cap, has an inner axial extent less than the sleeve axial extent, with the encoder rotationally related to the rotor. A motor is located concentrically to the rotor and between the annular end and the annular end cap and within the annular sleeve, with the annular end and the annular sleeve integrally formed as a single unitary piece.

Illustrative embodiments will become clearer in light of the following detailed description in connection with the drawings.

The illustrative embodiments may best be described by reference to the accompanying drawings where:.

All figures are drawn for ease of explanation of the basic teachings only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the illustrative embodiments will be explained or will be within the skill of the art after the following description has been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following description has been read and understood.

Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms "top", "bottom", "first", "second", "forward", "rearward", "reverse", "front", "back", "height", "width", "length", "end", "side", "horizontal", "vertical", "axial", "radial", "longitudinal", "lateral", and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the illustrative embodiments.

A sealed rotary table is shown in the drawings and generally designated <NUM>. Rotary table <NUM> generally includes a drive station <NUM> and a platform <NUM>. Platform <NUM> includes a planar annular disc <NUM> having an annular wall <NUM> extending axially from annular disc <NUM> located concentrically within an outer periphery of annular disc <NUM> to define a mounting flange <NUM> located radially outward of annular wall <NUM>. A seal ledge <NUM> is located at the free end of annular wall <NUM>. Platform <NUM> further includes an enclosure <NUM> including a top <NUM> generally of a U-shape parallel to annular disc <NUM> integrally connected to annular wall <NUM> and extending radially outwardly opposite to seal ledge <NUM>. Enclosure <NUM> further includes a U-shaped panel <NUM> integrally extending axially from the outer periphery of top <NUM>, integrally extending from annular wall <NUM>, and terminating in a flange <NUM> integrally connected to mounting flange <NUM> and extending radially outward of panel <NUM>. The free edge of panel <NUM> opposite to top <NUM> defines a lower opening. An opening <NUM> is formed in annular wall <NUM> corresponding to enclosure <NUM>, and annular disc <NUM> includes an arcuate cutout <NUM> corresponding to enclosure <NUM> and opening <NUM>. Annular disc <NUM> further includes an annular protrusion <NUM> extending from its top surface concentrically around a center opening <NUM> and extending axially from annular disc <NUM> in the same direction as annular wall <NUM>. Annular disc <NUM> also includes first and second channels <NUM> extending radially from center opening <NUM> to the outer periphery of mounting flange <NUM>. Annular disc <NUM>, annular wall <NUM>, annular protrusion <NUM> and enclosure <NUM> are integrally formed as a single, inseparable element formed of homogenous material and define a case.

Platform <NUM> further includes an annular output <NUM> including an outer driven gear <NUM>. A bearing <NUM> has an inner race <NUM> abutting with annular protrusion <NUM> and sandwiched against annular disc <NUM> by a bearing cap <NUM> mounted to protrusion <NUM>, with bearing <NUM> rotatably mounting output <NUM> to the case about an axis and within the case. Bearing cap <NUM> has generally L-shaped cross sections and includes an axially extending portion and a radially extending portion extending radially onwardly of the axially extending portion. An O-ring <NUM> is provided in a cavity formed in a lower surface of the free end of the axially extending portion of bearing cap <NUM> abutting with an upper annular free end of annular protrusion <NUM> and is in sealing engagement with the inner axial surface of inner race <NUM>. Race <NUM> abuts with the axially extending portion of bearing cap <NUM> and with annular protrusion <NUM>. Outer race <NUM> of bearing <NUM> is connected to annular output <NUM> such as by fasteners <NUM> extending through race <NUM> and suitably secured to output <NUM> such as by threading and extending parallel to the rotation axis of output <NUM>. An annular seal <NUM> is supported upon outer race <NUM> and extends between the annular free end of the radially extending portion of bearing cap <NUM> and output <NUM>, and an annular seal <NUM> is supported upon seal ledge <NUM> and extends between annular wall <NUM> and output <NUM>.

The normal intent of output <NUM> is to alter the speed and torque of another adjacent or meshed part/assembly. Bearing <NUM> is used to provide low friction rotation between a mounting surface <NUM> and outer driven gear <NUM>. It should be appreciated that output <NUM> in rotary table <NUM> has multiple functionalities. Output <NUM> includes a cylindrical flange <NUM>, a locating pilot, mounting surface <NUM>, and mounting holes <NUM> providing a large open center and for attaching componentry. Outer driven gear <NUM> is parallel to, intermediate, and spaced from planar annular disc <NUM> and cylindrical flange <NUM>, with outer drive gear <NUM> having a radial extent outward of cylindrical flange <NUM>. Mounting holes <NUM> extend axially from a top surface of cylindrical flange <NUM> and radially intermediate the inner and outer diameters of cylindrical flange <NUM>. The outer and inner diameters of cylindrical flange <NUM> also act as sealing surfaces for seals <NUM> and <NUM> to inhibit contamination from reaching internally. Output <NUM> further includes an annular pilot recess <NUM> on a lower surface thereof for locating outer race <NUM> and for attachment by fasteners <NUM> extending parallel to the rotation axis of output <NUM> and extending through race <NUM> and suitably secured to output <NUM> such as by threading. The shape of output <NUM> supports all of these functions while accepting the required meshing geometry of a mating pinion <NUM>.

Output <NUM> is a single, inseparable element formed of homogeneous material to provide increased stiffness between driven torque provided by output <NUM> and the added componentry, improving servo controllability and predictability. Further, improved manufacturing stack ups is provided between bearing rotation, user output connection, and gear tooth variability. Optimized machining of gear tooth variation about the bearing center rotation improves the overall accuracy specifications. Added componentry spinning true to the bearing's center of rotation minimizes rotational error and vibration in applications. Further, a single piece part with all of the capabilities listed above reduces cost and assembly time, thus improving manufacturability.

Similarly, platform <NUM> provides multiple functionalities. Protrusion <NUM> provides increased rigidity and supports and captures bearing <NUM>. Annular wall <NUM> provides increased rigidity, internally shields rotary table <NUM> from the outside environment and includes seal ledge <NUM>. Radially extended, top-enclosed enclosure <NUM> encapsulates the drive station <NUM> of rotary table <NUM> providing additional stiffness to combat the reaction loads of dynamic movements to resist deflection from reaction forces between driven gear <NUM> and pinion <NUM> while shielding drive station <NUM> from the outside environment. An open slot <NUM> located in the bottom of enclosure <NUM>, opening <NUM>, and arcuate cutout <NUM> provide full disengagement and re-engagement of drive station <NUM> for assembly and maintenance purposes. Open slot <NUM> is surrounded by mounting holes <NUM> for attaching drive station <NUM>. Mounting flange <NUM> provides mounting holes <NUM> for installation in the user's application, and channels <NUM> provide a route for wiring, tubing or the like to pass from center opening <NUM> past the periphery of mounting flange <NUM> on the user's application.

Likewise, the bearing cap <NUM> captures bearing <NUM> through the use of fasteners <NUM> threaded into mounting holes <NUM> in protrusion <NUM>. The outer diameter of bearing cap <NUM> also acts as a sealing surface for seal <NUM>. Radial holes can be provided in bearing cap <NUM> to provide access to the central bearing's greasing holes.

Pinion <NUM> is of the type of <CIT>, which is incorporated herein by reference, and includes rollers <NUM> circumferentially arranged to be supported by a pair of annular plates <NUM>. Each of rollers <NUM> of pinion <NUM> is rotationally supported between the pair of annular plates <NUM> by bearings <NUM> received in sockets in the pair of annular plates <NUM>. Rollers <NUM> are positioned in parallel with each other at regular intervals in the circumferential direction and between the pair of annular plates <NUM> and are adapted to mesh concurrently with corresponding teeth of driver gear <NUM>.

Pinion <NUM> is suitably connected to a rotor <NUM>, in the form shown as being a stub shaft. In the form shown, pinion <NUM> is connected to rotor <NUM> by having rotor <NUM> and the pair of annular plates <NUM> integrally formed as a single, inseparable element formed of homogeneous material.

Generally, drive station <NUM> includes a housing <NUM> mounted to the case and rotating output <NUM>, with housing <NUM> having an annular end <NUM>. An annular sleeve <NUM> extends axially from annular end <NUM> parallel to the rotation axis of output <NUM> and of rotor <NUM> to define a mounting flange <NUM> located radially outward of annular end <NUM>. A plurality of mounting holes <NUM> is formed in mounting flange <NUM> to receive fasteners <NUM> threadably received in mounting holes <NUM> and extending parallel to the rotation axis of output <NUM> and of rotor <NUM>. Mounting holes <NUM> are non-circular and have a cross sectional size larger than the cross sectional size of fasteners <NUM>. Mounting flange <NUM> and mounting holes <NUM> mount drive station <NUM>, such that the axis of rotation of pinion <NUM> and rotor <NUM> is off center in order to accommodate different pinion and gear meshing diameters, providing flexibility and product modularity. Further, in order to achieve proper mesh of drive gear <NUM> and pinion <NUM>, pinion <NUM> and rotor <NUM> must be preloaded into driven gear <NUM>. It should be appreciated that the larger cross section of mounting holes <NUM> allows drive station <NUM> to be mounted with fasteners <NUM> in an untightened fashion, the drive station <NUM> to be preloaded, and then fasteners <NUM> to fix drive station <NUM> in the preloaded position. Furthermore, slot <NUM>, opening <NUM> and cutout <NUM> provide full disengagement and re-engagement of drive station <NUM> for modularity in assembly and maintenance purposes.

A bearing <NUM> is sandwiched between a radially inwardly extending flange <NUM> formed inside annular end <NUM> and a radially outwardly extending shoulder <NUM> formed on the lower annular plate <NUM>. A seal <NUM> is supported upon a radially inwardly extending shoulder formed inside annular end <NUM> and extends between the annular end <NUM> and an axial surface of rotor <NUM> to seal drive station <NUM> from the environment.

Drive station <NUM> further includes an annular end cap <NUM> of a stepped frustoconical shape and a preload cap <NUM> removably connected to an end of rotor <NUM>. End cap <NUM> is secured to the annular end of sleeve <NUM> such as by fasteners extending through end cap <NUM> and secured to sleeve <NUM>, such as by being threaded. A bearing <NUM> is sandwiched between preload cap <NUM> and a radially extending inner flange of annular end cap <NUM>. Bearing <NUM> is sandwiched between rotor <NUM> and an inner axial opening formed in annular end <NUM> and between a shoulder defined on rotor <NUM> and a flange extending radially inwardly from the inner axial opening of annular end <NUM>. Bearing <NUM> is at an axial extent from annular end <NUM> less than the axial extent of sleeve <NUM> and generally equal to or less than the axial extent of rotor <NUM>. Thus, rotor <NUM> is rotatably supported and preloaded between bearings <NUM> and <NUM> in drive station <NUM>.

An encoder <NUM> is received in an axial cavity formed in annular end cap <NUM> and includes a frustoconical protrusion <NUM> extending through preload cap <NUM> and into a corresponding bore formed in the end of rotor <NUM>. The inner axial extent of encoder <NUM> is less than the axial extent of sleeve <NUM>. Encoder <NUM> is rotatably related to rotor <NUM>. Rotary table <NUM> includes a motor located concentrically to rotor <NUM> and having a first motor component <NUM>, such as windings, secured to housing <NUM> by suitable provisions such as adhesive and extends from annular end <NUM> to an extent less than annular sleeve <NUM> but greater than rotor <NUM>. A second motor component <NUM>, such as permanent magnets, is secured to rotor <NUM> by suitable provisions such as fasteners threadly received in an axial end of lower annular plate <NUM>. The second motor component <NUM> has an axial extent less than first motor component <NUM>, a first end axially spaced from annular end <NUM> and a second end generally at the same axial extent as rotor <NUM> from annular end <NUM>.

It should be appreciated that rotor <NUM> and the pair of annular plates <NUM> formed as a single, inseparable element creates a high stiffness and allows rotor <NUM> to be shortened to fit inside the extents of motor components <NUM> and <NUM> to minimize the overall length of drive station <NUM>. Further, encoder <NUM> is located within the axial extent of annular sleeve <NUM> of housing <NUM>. Thus, drive station <NUM> has a minimal overall length.

Claim 1:
Motion control apparatus including a case including a planar annular disc (<NUM>) and an annular wall (<NUM>) extending from the planar annular disc (<NUM>) and having a free end, an output (<NUM>), a bearing (<NUM>) rotatably mounting the output (<NUM>) to the case about an axis and within the annular wall (<NUM>) extending axially from the planar annular disc (<NUM>), and a drive station (<NUM>) mounted to the case and rotating the output (<NUM>), wherein the case further includes an enclosure (<NUM>) having a panel (<NUM>) integrally connected to the annular wall (<NUM>) and extending radially outward opposite to the output (<NUM>), a top (<NUM>) integrally formed with the panel (<NUM>), and a lower opening defined by the panel (<NUM>) opposite to the top (<NUM>) and radially aligned with the planar annular disc (<NUM>), with the panel (<NUM>) and the lower opening having cross sections perpendicular to the axis which are U-shaped, with the annular wall (<NUM>) including a side opening (<NUM>) corresponding to the enclosure (<NUM>), with the planar annular disc (<NUM>) including an arcuate cutout (<NUM>) corresponding to the enclosure (<NUM>) and the side opening (<NUM>), with the drive station (<NUM>) extending in the lower opening, the side opening (<NUM>) and the arcuate cutout (<NUM>) and rotatably engaging with the output (<NUM>), wherein the planar annular disc (<NUM>), the annular wall (<NUM>) and the enclosure (<NUM>) are integrally formed as a single, inseparable piece part of homogenous material.