Polycrystalline diamond bearing pads with bearing portions exhibiting different wear rates and related bearing assemblies and apparatuses

A bearing assembly for use in a subterranean drilling system, comprising:

• a support ring;
• and
• a plurality of polycrystalline diamond bearing pads mounted to the support ring, the plurality of polycrystalline diamond bearing pads distributed circumferentially about an axis, a number of the plurality of polycrystalline diamond bearing pads including a polycrystalline diamond bearing pad body defining at least one side surface and an upper surface, the polycrystalline diamond bearing pad body including a plurality of directly-bonded together diamond grains, the polycrystalline diamond bearing pad body further including:
• a first bearing pad portion including a first superhard bearing surface exhibiting a first wear resistance;
• and
• a second bearing pad portion including a second superhard bearing surface exhibiting a second wear resistance greater than the first wear resistance, wherein the first bearing surface and the second bearing surface at least partially define the upper surface of the polycrystalline diamond bearing pad body.

A bearing apparatus for use in a subterranean drilling system, comprising:

• a first bearing assembly including,
• a support ring;
• and
• a plurality of first superhard bearing elements mounted to the support ring, the plurality of first polycrystalline superhard bearing elements distributed circumferentially about an axis, a number of the plurality of first superhard bearing elements including a polycrystalline diamond bearing pad body defining at least one side surface and an upper surface, the polycrystalline diamond bearing pad body including a plurality of directly-bonded together diamond grains, wherein the polycrystalline diamond bearing pad body further includes:
• a first bearing pad portion including a first superhard bearing surface exhibiting a first wear resistance;
• and
• a second bearing pad portion including a second superhard bearing surface exhibiting a second wear resistance greater than the first wear resistance, wherein the first superhard bearing surface and the second superhard bearing surface at least partially define the upper surface of the polycrystalline diamond bearing pad body;
• and
• a second bearing assembly including a plurality of second superhard bearing elements generally opposing the plurality of first superhard bearing elements of the first bearing assembly and distributed circumferentially about the axis.

A motor assembly for use in a subterranean drilling system, comprising:

• a motor operable to apply torque to a rotary drill bit;
• and
• a bearing apparatus operably coupled to the motor, the bearing apparatus including a rotor and a stator;
• and
• wherein at least one of the rotor or the stator comprises:
• a support ring;
• and
• a plurality of polycrystalline diamond bearing pads mounted to the support ring, the plurality of polycrystalline diamond bearing pads distributed circumferentially about an axis, a number of the plurality of polycrystalline diamond bearing pads including a polycrystalline diamond bearing pad body defining at least one side surface and an upper surface, the polycrystalline diamond bearing pad body including a plurality of directly-bonded together diamond grains, the polycrystalline diamond bearing pad body further including:
• a first bearing pad portion including a first superhard bearing surface exhibiting a first wear resistance;
• and
• a second bearing pad portion including a second superhard bearing surface exhibiting a second wear resistance greater than the first wear resistance, wherein the first superhard bearing surface and the second superhard bearing surface at least partially define the upper surface of the polycrystalline diamond bearing pad body.