Abstract:
A roller bearing assembly includes an outer race (1) prepared from a steel plate and a plurality of rollers (2) wherein the outer race (1) has a raceway surface (1a) to which induction hardening and tempering are applied. The outer race (1) is a shell type. In addition to the raceway surface (1a), an inner surface of an annular collar (6) at one end of the outer race (1) is also subjected to the induction hardening and tempering. An opposite annular collar (7) is left as a raw material without being heat treated so that it can be easily bent.
Abstract:
When a plurality of outer rings (R) are sequentially and inductively heated to a target temperature by energizing a heating coil (2) elongated more than each of the plurality of outer rings (R), which are made of steel and retained coaxially by a retaining unit (3), while relatively moving the outer rings (R) and the heating coil (2) in an axial direction, an output of the heating coil (2) is varied in consideration of the number of outer rings (R) present in an opposing region of the heating coil (2).
Abstract:
When a plurality of outer rings (R) are sequentially and inductively heated to a target temperature by energizing a heating coil (2) elongated more than each of the plurality of outer rings (R), which are made of steel and retained coaxially by a retaining unit (3), while relatively moving the outer rings (R) and the heating coil (2) in an axial direction, an output of the heating coil (2) is varied in consideration of the number of outer rings (R) present in an opposing region of the heating coil (2).
Abstract:
In a heating step (S1) of inductively heating a steel ring-shaped member (R) to a target temperature, a plurality of ring-shaped members (R) retained by a retaining unit (3) coaxially with each other are caused to sequentially pass through an opposing region of a first heating coil (21) having a constant output, and through an opposing region of a second heating coil (22) having a variable output and being arranged coaxially with the first heating coil (21) on an exit side of the first heating coil (21). Thus, the plurality of ring-shaped members (R) are sequentially and inductively heated to the target temperature.
Abstract:
To further reduce the manufacturing cost of a shell type needle roller bearing, and to ensure high quality of the shell type outer ring by subjecting the outer ring to a heat treatment that needs no adjustment of the atmosphere.The steel sheet to be formed into the shell type outer ring 1 by pressing is made of a medium to high carbon steel containing carbon by not less than 0.3 mass percent. With this arrangement, the material cost and thus the manufacturing cost are lower than when using a conventional low-carbon structural alloy steel sheet or a steel sheet for cold rolling and pressing. Also, it is possible to ensure high quality of the outer ring by subjecting the outer ring to simple heat treatment without the need for carburizing or carbonitriding, which needs adjustment of the atmosphere.
Abstract:
A power transmission shaft including a male spline formed in an outer periphery thereof, and a diameter increasing portion formed on a part of a tooth bottom of the male spline, which is located on an opposite side to an axial end of the power transmission shaft. The tooth bottom of the male spline has a substantially constant circumferential width extending up to an axial region of the diameter increasing portion. The diameter increasing portion includes a chamfered portion formed in the axial region of the diameter increasing portion, the chamfered portion connecting the tooth bottom and a tooth flank of the male spline to each other to reduce a tooth groove width.
Abstract:
A hollow shaft material is provided with, on an outer peripheral surface side thereof, for example, a movable induction heating coil wrapped therearound. While a high-frequency current with a predetermined frequency is caused to flow through the induction heating coil, the induction heating coil is axially moved to perform induction hardening of the hollow shaft material from the outer peripheral surface side. At this moment, the frequency of the high-frequency current caused to flow through the induction heating coil is set relatively low as to the small-diameter portions, which have a relatively small thickness, and the frequency of the high-frequency current caused to flow through the induction heating coil is set relatively high as to the large-diameter portion, which has a relatively small thickness.
Abstract:
A shell type needle roller bearing includes an outer ring and a plurality of needle rollers arranged along an inner raceway of the outer ring. A steel sheet to be formed into the shell type outer ring 1 by pressing is made of a medium to high carbon steel containing carbon by not less than 0.3 mass percent.
Abstract:
Provided is a method of manufacturing a hollow power transmission shaft, which makes it possible to ensure stable quality even when there is a difference in wall thickness or hardening ratio along an axial direction thereof. A hollow shaft material (1′) is provided with, on an outer peripheral surface (1g) side thereof, for example, a movable induction heating coil (5) wrapped therearound. While a high-frequency current with a predetermined frequency is caused to flow through the induction heating coil (5), the induction heating coil (5) is axially moved to perform induction hardening of the hollow shaft material (1′) from the outer peripheral surface (1g) side. At this moment, the frequency of the high-frequency current caused to flow through the induction heating coil (5) is set relatively low as to the small-diameter portions (1b), which have a relatively small thickness, and the frequency of the high-frequency current caused to flow through the induction heating coil (5) is set relatively high as to the large-diameter portion (1a), which has a relatively small thickness.