Abstract: A heat treatment apparatus that thermally treats an annular workpiece formed of a steel material by inductively heating the workpiece includes a treatment tank in which the workpiece is set and thermally treated, a holding portion that holds the workpiece at a predetermined position, an induction heating coil that surrounds the workpiece to inductively heat the workpiece, and a cooling medium that cools surfaces of the workpiece during the induction heating of the workpiece.

Abstract: A split outer ring of a split rolling bearing, which splits in a radial direction, includes a pair of split outer ring members which are each formed into a semi-cylindrical shape and which are formed into a cylindrical shape by being butted against each other at circumferential end portions. A pair of first flat plane portions which extend from both axial end edges of the end portions towards a center in parallel with an axis and a V-shaped recess portion, positioned between the first flat plane portions and is recessed in a circumferential direction relative to the pair of first flat plane portions, are formed at one end portion of the circumferential end portions which are butted against each other, and a pair of second flat plane portions which extend from the both axial end edges in parallel with the axis.

Abstract: A bearing structure includes a housing including a first housing portion and a second housing portion forming together with the first housing portion, a cross-sectionally generally-circular support hole, and a rolling bearing including a pair of outer rings mounted within the support hole of the housing in closely-contacted relation thereto, a plurality of rolling elements mounted to be able to roll on inner side surfaces of the pair of outer rings, and a pair of cages holding the rolling elements. The first housing portion and the second housing portion are mounted in an offset relation to each other in a radial direction so that at mating surfaces of circumferential end portions of the pair of outer rings, the outer ring end portions disposed at an upstream side with respect to a direction of rotation of the shaft form radially inwardly-projecting steps, respectively.

Abstract: A tapered roller bearing includes: an oil guide member that opens and closes an annular opening between an outer peripheral surface of a large rib of an inner ring and an outer ring and is mounted on the large rib; and a discharge port that discharges, along the outer peripheral surface of the large rib, lubricating oil and is formed through an inner peripheral portion of the oil guide member. The oil guide member includes a closing portion for closing the annular opening. When a fluid pressure of the lubricating oil which flows through pockets of a cage toward an inner peripheral surface of the outer ring is below a predetermined values, the closing portion closes the annular opening and guides the lubricating oil toward the discharge port. When the fluid pressure exceeds the predetermined value, the closing portion opens the annular opening.

Abstract: There are provided a split outer ring which can suppress the reduction in durability and which can suppress largely the generation of noise or vibration which is caused in association with the passage of rolling elements over a mating surface and a split rolling bearing which employs the same outer ring. A split outer ring 2 according to the invention has first and second split outer ring members 5, 6 which are formed into a cylindrical shape by being butted against each other at circumferential end portions. First flat plane portions 7 and a V-shaped recess portion 8 which is recessed in a circumferential direction are formed at one end portion 5a of the circumferential end portions which are butted against each other.

Abstract: To provide a bearing structure in which the processing is easy, and the manufacturing cost can be reduced.

Abstract: Guide grooves for guiding lubricating oil from a small rib-side end portion of an inner ring to a large rib-side end portion thereof are formed at an inner periphery of a cage.

Abstract: A tapered roller bearing includes: an oil guide member that opens and closes an annular opening between an outer peripheral surface of a large rib of an inner ring and an outer ring and is mounted on the large rib; and a discharge port that discharges, along the outer peripheral surface of the large rib, lubricating oil and is formed through an inner peripheral portion of the oil guide member. The oil guide member includes a closing portion for closing the annular opening. When a fluid pressure of the lubricating oil which flows through pockets of a cage toward an inner peripheral surface of the outer ring is below a predetermined values, the closing portion closes the annular opening and guides the lubricating oil toward the discharge port. When the fluid pressure exceeds the predetermined value, the closing portion opens the annular opening.

Abstract: A tapered roller bearing includes an inner ring, an outer ring, a plurality of tapered rollers, and a cage. The cage includes a large diameter-side annular section, a small diameter-side annular section, and pillar sections connecting the large diameter-side annular section and the small diameter-side annular section and forming pockets retaining the tapered rollers. The radially inner surfaces of the pillar sections are disposed closer to the center than a pitch circle of the tapered rollers and are inclined from the small diameter-side annular section toward the large diameter-side annular section, thereby forming guide surfaces that guide lubricating oil toward the large rib. Roller holding portions are formed on side portions of the pillar sections so as to protrude along the outer peripheral surfaces of the tapered rollers to a position located at the outer side in the radial direction than the pitch circle.

Abstract: A machine part has a rolling contact surface (11a) having a lot of very small recesses which are independent of each other formed thereon. The maximum height (Ry) of a roughness profile (R) obtained by cutting the contact surface (11a) by a plane perpendicular to the contact surface (11a) is 1 to 3 .mu.m, and the peak height Rp of a center line of the roughness profile (R) and the valley depth Rv of the center line satisfy the relationship of Rp/Rv.ltoreq.0.3. In this case, the contact surface (11a) has very low crests which are relatively densely distributed and very deep troughs which are relatively sparsely distributed. A sufficiently wide contact area is ensured by the former very low crests which are relatively densely distributed. An oil sump in a sufficient amount is formed by the latter deep troughs which are sparsely distributed.

Abstract: A machine part has a rolling contact surface (11a) having a lot of very small recesses which are independent of each other. The maximum height (Ry) of a roughness profile (R) obtained by cutting the contact surface (11a) by a plane perpendicular to the contact surface (11a) is 1 to 3 .mu.m. The reduced peak height R.sub.PK obtained on the basis of a load curve M obtained from the roughness profile R satisfies the relationship of R.sub.PK /Ry<0.1 with the maximum height Ry. In this case, the contact surface has very small recesses which are sparsely distributed but are deep, so that it is relatively smooth near its surface. A sufficiently large contact area is ensured by the smooth portion near the surface, and an oil sump in a sufficient amount is formed by the very small recesses which-are sparsely distributed but are deep.