The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 10, 1996
Filed:
Oct. 11, 1994
Naoki Ohta, Wako, JP;
Naoki Kamide, Wako, JP;
Jun Iwamoto, Wako, JP;
Yasunobu Kawakami, Wako, JP;
Tsutomu Hayashi, Wako, JP;
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A swash-plate hydraulic pressure device for use as a hydraulic pump or motor includes a cylinder block having an annular array of cylinder holes defined therein around an axis. A plurality of plungers of a ceramic material are reciprocally movably disposed in the cylinder holes, respectively, the plungers having respective partly spherical tip ends. A swash plate of metal is disposed around the cylinder block for rotation with respect to the cylinder block, the swash plate having a annular groove of a partly spherical cross section defined therein and, the partly spherical tip ends of the plungers engaging in the groove. The tip ends of the plungers preferably have a pore area percentage of at most 7.8% and a maximum surface roughness of at most 1.6 s. The partly spherical tip end of each of the plungers has a radius R.sub.0 of curvature, each of the plungers has a diameter D, the groove has a radius R.sub.1 of curvature and a depth E. The ratios R.sub.0 /D, R.sub.0 /R.sub.1, and E/R.sub.0 preferably are in the ranges of 0.52.ltoreq.R.sub.0 /D.ltoreq.0.62, 0.81.ltoreq.R.sub.0 /R.sub.1 .ltoreq.0.87, and 0.36.ltoreq.E/R.sub.0 .ltoreq.0.42. Each of the plungers has a beveled surface on an end thereof opposite to the partly spherical tip end thereof, the beveled or rounded surface preferably having an axial depth of at least 0.6 mm.