Rolling bearing, hub unit, rolling contact member, universal joint, torque transmission member for universal joint, and method of producing the same

A hub unit posed between a vehicular wheel and a vehicular body and supporting said vehicular wheel relative to said vehicular body rotatably, comprising:

• an outer member having an inner circumferential surface having an annular raceway surface;
• an inner member disposed radially inner than said outer member and having an annular raceway surface opposite to said raceway surface of said outer member;
• and
• a plurality of rolling elements disposed in contact with said raceway surface of said outer member and said raceway surface of said inner member on an annular raceway, said rolling element being configured of a sintered body that contains as a main component a β-sialon represented by a compositional formula of Si6-ZAlZOZN8-Z and satisfying 0.1≦z≦3.5 and has a remainder formed of an impurity, said rolling element having a rolling contact surface serving as a surface contacting one of said outer member and said inner member, said rolling contact surface being included in a portion having a high density layer higher in density than an inner portion, said high density layer having a surface included in a portion having a higher density layer higher in density than another portion of said high density layer.

A hub unit posed between a vehicular wheel and a vehicular body and supporting said vehicular wheel relative to said vehicular body rotatably, comprising:

• an outer member having an inner circumferential surface having an annular raceway surface;
• an inner member disposed radially inner than said outer member and having an annular raceway surface opposite to said raceway surface of said outer member;
• and
• a plurality of rolling elements disposed in contact with said raceway surface of said outer member and said raceway surface of said inner member on an annular raceway, said rolling element being configured of a sintered body that contains as a main component a β-sialon represented by a compositional formula of Si6-ZAlZOZN8-Z and satisfying 0.1≦z≦3.5 and has a remainder formed of a sintering additive and an impurity, said rolling element having a rolling contact surface serving as a surface contacting one of said outer member and said inner member, said rolling contact surface being included in a portion having a high density layer higher in density than an inner portion, said high density layer having a surface included in a portion having a higher density layer higher in density than another portion of said high density layer.

A method of producing a torque transmission member for a universal joint, provided in a universal joint between a race member connected to a first shaft member and a second shaft member rollably and slidably and transmitting rotation transmitted to one of said first shaft member and said second shaft member about an axis to the other of said first shaft member and said second shaft member, comprising the steps of:

• preparing a powdery source material that contains as a main component a β-sialon represented by a compositional formula of Si6-ZAlZOZN8-Z and satisfying 0.1≦z≦3.5 and has a remainder formed of an impurity;
• shaping said powdery source material generally into a geometry of said torque transmission member for said universal joint to provide a shaped body;
• and
• sintering said shaped body at a pressure equal to or smaller than 1 MPa, said torque transmission member having a contact surface service as a surface contacting another member, said contact surface being included in a portion having a high density layer higher in density than an inner portion, said high density layer having a surface included in a portion having a higher density layer higher in density than another portion of said high density layer.

A method of producing a torque transmission member for a universal joint, provided in a universal joint between a race member connected to a first shaft member and a second shaft member rollably and slidably and transmitting rotation transmitted to one of said first shaft member and said second shaft member about an axis to the other of said first shaft member and said second shaft member, comprising the steps of:

• preparing a powdery source material that contains as a main component a β-sialon represented by a compositional formula of Si6-ZAlZOZN8-Z and satisfying 0.1≦z≦3.5 and has a remainder formed of a sintering additive and an impurity;
• shaping said powdery source material generally into a geometry of said torque transmission member for said universal joint to provide a shaped body;
• and
• sintering said shaped body at a pressure equal to or smaller than 1 MPa, said torque transmission member having a contact surface service as a surface contacting another member, said contact surface being included in a portion having a high density layer higher in density than an inner portion, said high density layer having a surface included in a portion having a higher density layer higher in density than another portion of said high density layer.