Fluid handling – Systems – Multi-way valve unit
Reexamination Certificate
2000-07-27
2001-10-09
Fox, John (Department: 3753)
Fluid handling
Systems
Multi-way valve unit
C029S890124
Reexamination Certificate
active
06298880
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a spool valve, and more particularly, to a spool valve having an inner hybrid construction and a method of manufacturing the same.
Conventionally, a spool valve provided in a sleeve for switching has been brought into practical use as a directional control valve intended for switching a hydraulic circuit for startup, stoppage, acceleration or deceleration in a hydraulic actuator or the like.
FIGS. 4 and 5
show a typical configuration of such spool valve. In such spool valve, sliding surface portions
11
, which form sealing portions between them and a sleeve inner surface (not shown), and ring-shaped grooves
12
, which define between them and the sleeve inner surface a passage for a working fluid, are arranged alternately adjacent to each other in a longitudinal direction of the spool valve (see an upper halves of the figures). The sliding surface portions and the ring-shaped grooves are generally integrally formed of a metal, for example, carbon steel (steel type: S45C) or the like (see lower halves of the figures).
Spool valves having such configuration are completed by cutting predetermined lengths of a rod-shaped stock of a desired material, and subjecting the same to many working processes, such as carburization hardening, straightening, centerless, deburring or the like, after machining in accordance with a designed shape. With such conventional spool valves, machining are implemented by a NC machine programmed, which operation requires skill. Further, prior art involves much man-hour for processing of products, and such processes as carburization hardening, straightening or the like, which involve heat treatment take substantial time for treatment. Accordingly, such conventional spool valves are liable to become costly, which makes reduction in manufacturing cost difficult, and there is a limitation on improvement in productivity.
SUMMARY OF THE INVENTION
The invention has been accomplished in order to solve the above-mentioned problems of prior art, and provides a spool valve, which achieves reduction in processing man-hour for manufacture as well as shortening of processing time and does not require skilled work while enabling reduction in manufacturing cost, and a method of manufacturing the same.
The above-mentioned problems can be solved by the invention that has a feature in a spool valve comprising sliding surface portions, which define sealing portions between them and an inner surface of a sleeve, and grooves, which define passages for a working fluid between them and the inner surface of the sleeve, the sliding surface portions and the grooves being arranged alternately adjacent to each other in a longitudinal direction of the spool valve, the sliding surface portions being formed by sliding members, which are provided on a base portion of a synthetic resin to be fitted thereon.
The spool valve of the invention can be preferably embodied by (1) an embodiment, in which base portions comprise a plurality of synthetic resin moldings formed on a periphery of a core material, and sliding members are mounted on peripheries of the respective base portions in fitted state, (2) an embodiment, in which a base portion comprises a synthetic resin molding formed to cover an entire outer periphery of the core material, and a plurality of sliding members are mounted to the base portion at predetermined locations in fitted state, (3) an embodiment, in which a base portion comprises a synthetic resin molding formed integrally to comprise a core material of the spool valve, and a plurality of sliding members are mounted to the base portion at predetermined locations in fitted state, and (4) an embodiment, in which the synthetic resin molding or moldings comprise a synthetic resin molding or moldings, to which an orientation property is given.
According to the invention, a desired spool valve can be manufactured by previously manufacturing sliding members, which are composed of, for example, ring-shaped metallic bodies and which are relatively easy to manufacture and simple in configuration, forming a base portion of a synthetic resin by means of the so-called insert molding, in which the sliding members are set in a cavity of a mold having a predetermined configuration and a predetermined synthetic resin is injected to perform molding integrally with the ring-shaped metallic bodies, and simultaneously making the sliding members integral with the base portion in fitting state. In this manner, the manufacturing method of the invention enables manufacturing a spool valve with less man-hour and short time in processing and without high skill.
REFERENCES:
patent: 4169578 (1979-10-01), Adams
patent: 4377896 (1983-03-01), Cox
patent: 5172727 (1992-12-01), Stoll et al.
patent: 5421367 (1995-06-01), Murata
patent: 5988591 (1999-11-01), Akimoto et al.
patent: 6052900 (2000-04-01), Campbell
Kakamu Hideki
Mori Toshiya
Aoyama Seisakusho Co., Ltd.
Conlin David G.
Corless Peter F.
Edwards & Angell LLP
Fox John
LandOfFree
Spool valve and manufacturing method therefor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Spool valve and manufacturing method therefor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spool valve and manufacturing method therefor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2591574