Ntn Corporation

Takahiro Koremoto

Masao Fukuwaka

Seiichi Nozaki

Hidenobu Mikami

Takayuki Kawamura

Motoharu Niki

Mitsunari Asao

Hiroki Iwamatsu

Masahiro Muranaka

Yoshiaki Suzuki

Tadahisa Suzuki

Tsutomu Mizutani

Yosiki Yamaguchi

Kazuhiro Matsumoto

Yoshio Kato

Tadaaki Maeda

Kunio Takemura

Takao Yoshimatsu

Masami Minami

Disclosed is a grease sealed bearing for automobile that has the high temperature resistance as well as shear stability, and prevents the noise at low temperature as well as the brittle flaking under high speed rotation and high load. The grease comprises a base oil containing a synthesized hydrocarbon oil and one or more ester oils at a weight ratio of 0.1 to 0.49:0.9 to 0.51; 5 to 30% by weight of a urea based thickener, and 0.1 to 10% by weight of dithiozinc phosphate based on the whole grease. The grease sealed bearing for automobile is obtained by sealing a bearing used in a device driven by an automobile engine with the grease.

Grease sealed bearing for automobile

Grease for fan bearing

According to the present invention, PAO oil and ester oil are mixed in a ratio by weight of from 50:50 to 90:10 to provide a base oil having a viscosity of not more than 70 mm,/S at 40&deg; C., to which base oil is then added 5-25% by weight of diurea, which is an alicyclic compound, serving as a thickener, and ZnDTC, which is an additive. The grease thus prepared is filled in a bearing,. This bearing,is fitted in the inner portion of a pulley body,having a pulley peripheral surface is to be contacted by a belt driven by the engine of an automobile. Thereby, brittle peeling occurring in the raceway surfaces and ball surfaces, and abnormal noise under cold ambient can be reliably prevented.

Bearing for automobile pulleys

A grease to be sealed in bearings which shows good lubricating properties within a wide temperature range from low to high temperatures, whereby it can prevent bearing noise while it is cold, and maintain its good properties including excellent high-temperature durability for a long period of time. The grease contains a base oil made up of a synthetic hydrocarbon oil and an ester synthetic oil having eight or more ester groups arranged in a comb-like fashion on one side of an oil chain molecule made up of eight of more carbon atoms, as expressed by Formula below, the ratio of contents in weight of the synthetic hydrocarbon oil and the ester synthetic oil being 0.65-0.75:0.35-0.25, and 5-20 wt % of a urea thickening agent. The grease may further contain 0.1-10 wt % dithiophosphate as an extreme pressure agent. The grease may be used as grease to be sealed in a ball bearing for supporting a pulley engaging belts for transmitting automotive engine torque to prevent noise immediately after the engine is started. ##STR1## (where R.sub.1 -R.sub.4 are alkyl groups, and x and y are integers greater than 1).

Grease to be sealed in bearing

Idler pulley

A slight clearance S1 is formed between the inner surface of the outer ring 2b and the outer surface of the cage 2d. The size of this slight clearance S1 is such that it causes concomitant rotation of the cage 2d associated with the rotation of the outer ring 2b.

Rolling contact bearing

Growing community of inventors

Iwata, Japan

Takahiro Koremoto