Topy Kogyo Kabushiki Kaisha

Isao Yoshida

Hiroyuki Takeno

Masahiro Nakajima

Makoto Takagi

Kiyokazu Niwa

Hisahiko Kusano

Go Morishima

Hirokatsu Niitsu

Akihiro Koishi

Kimio Goto

Yoshio Hamajima

A structure for standardizing at least one kind of part of a roller assembly for a construction vehicle so that the part can be used for a same size of construction vehicles having different structural specifications of a plurality of construction vehicle makers. The at least one kind of part includes at least one of a shell, a shaft, a floating seal, a bushing and a collar. Structural specifications including the configuration and dimension, the kind of steel or material, and the heat treatment specification or the mechanical property for the at least one kind of part are unified as much as possible over the same size of the construction vehicles of a plurality of construction vehicle makers.

Structure for standardizing parts of a roller assembly for a construction vehicle

An endless track includes an iron link belt, a continuous pad, and a connecting device. The iron link belt includes a link unit assembly constructed of a plurality of link units connected to each other. Each link unit includes a pair of links. The iron link belt may include a plate welded to the pair of links and extending perpendicularly to a direction in which the link unit assembly extends. The continuous pad includes the same number of core metal plates as that of the link units, and a single rubber belt covering and being vulcanization-adhered to a ground opposing surface of each of the core metal plates. The rubber belt extends continuously over all of the core metal plates. The rubber belt may include a small thickness portion positioned between two adjacent core metal plates. The connecting device connects the iron link belt and the continuous pad.

Endless track and a manufacturing method thereof

A method for heat-treating a hollow cylindrical workpiece includes quench-hardening including a first step and a second step. In the first step, during continuously conveying the workpiece in a horizontal direction without a space between adjacent workpieces, an entirety of the workpiece is subjected to induction-heating conducted from an outside surface of the workpiece only, and a temperature of the workpiece is made uniform before the workpiece reaches a cooling portion spaced from a heating portion. Then, cooling the workpiece is initiated before the temperature of the workpiece falls to Ar,temperature and an entire cross-section of a wall of the workpiece is quench-hardened. In the second step, during continuously conveying the workpiece in the horizontal direction, induction-heating is conducted only to an outside portion of the workpiece, the induction-heating being conducted from the outside surface only. Immediately after that, the workpiece is cooled from the outside surface thereby re-quench-hardening the outside portion, so that both the outside portion and the inside portion of the workpiece have a hardness greater than an effective hardness, and a core portion of a wall of the workpiece has a hardness less than the effective hardness.

Method for heat-treating a hollow cylindrical workpiece

A production method for an endless track bushing wherein high-carbon low-alloy steel is selected as a bushing material, the bushing material is quench-hardened without pre-carburizing the bushing material, and then tempered. In the quench-hardening, the bushing material is induction-heated from an outside surface of the bushing material only so that an inside surface of the bushing material is heated to a temperature above and close to a transformation temperature of the high-carbon low-alloy steel, and then the heated bushing material is cooled from the outside surface of the bushing material only so that a residual compressive stress is produced at the inside surface of the bushing material when it has been cooled to an ambient temperature. The thus produced bushing has a high hardness throughout the entire cross section and a high toughness.

Production method for a vehicular endless track bushing

Growing community of inventors

Chigasaki, Japan

Isao Yoshida