Rotary expansible chamber devices – With mechanical sealing – Axially movable end wall or end wall portion
Patent
1992-08-07
1993-08-03
Bertsch, Richard A.
Rotary expansible chamber devices
With mechanical sealing
Axially movable end wall or end wall portion
F01C 1908
Patent
active
052323560
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a seal device for a gear pump.
BACKGROUND TECHNOLOGY
In a conventional gear pump as illustrated in FIG. 6, a pair of gears 2 and 3 meshing with each other are rotatably contained in a gear case 1 which is closed by side plates 4 at both sides thereof.
As illustrated in FIG. 7, seals 5 are disposed between the case 1 and the side plates 4 for preventing oil leakage and for providing a pressure balancing high pressure chamber in the gear case 1.
Each of the seals 5 has a shape as illustrated in FIG. 8 and cross sectional shapes as illustrated in FIGS. 9(a), 9(b), 9(c) and 9(d) respectively. The seals comprise projections 5a made of rubber and projections 5b formed by injection molding of fluorocarbon resin.
In the conventional seal device for the gear pump, there is a possibility of generating a crack a at the connecting part 5c of projections 5a when a tensile force acts on the connecting part 5c shown in FIG. 9(d) if an inner pressure is applied to the seal 5.
No oil leakage occurs at the crack a in the connecting part 5c. However, if the crack a develops to thereby generate new cracks b at the projections 5a, there is a likelihood of oil leakage at the cracks b.
Accordingly, the present invention has been made to solve the drawbacks set forth above and to provide a seal device for a gear pump capable of generating cracks concentratedly at the connecting part of projections to thereby prevent oil leakage.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to achieve the above object and to provide a seal device for a gear pump, and, in the gear pump whose gear case rotatably containing a pair of gears meshing with each other is closed by side plates at both sides thereof interposing seals therebetween, said seal is formed of a plurality of annular parts, projections formed on the annular parts, a connecting part for connecting the projections at the portions where the same are close to each other, and a notch formed on at least one side of said connecting part, whereby even when a tensile force acts on the connecting part during the use of the device, a crack concentratedly develops at the notch and is prevented from developing at the other parts, whereby oil leakage can be prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a seal according to an embodiment of the present invention,
FIG. 2 is a cross-sectional view taken along II--II of FIG. 1,
FIG. 3 is a cross-sectional view taken along II--III of FIG. 1,
FIG. 4 is a cross-sectional view taken along IV--IV of FIG. 1,
FIG. 5 is a cross-sectional view taken along V--V of FIG. 1,
FIG. 6 is a cross-sectional view of a gear pump,
FIG. 7 is a cross-sectional view taken along VII--VII of FIG. 6,
FIG. 8 is a plan view of a conventional seal,
FIG. 9(a) is a cross-sectional view taken along A--A of FIG. 8,
FIG. 9(b) is a cross-sectional view taken along B--B of FIG. 8,
FIG. 9(c) is a cross-sectional view taken along C--C of FIG. 8, and
FIG. 9(d) is a cross-sectional view taken along D--D of FIG. 8.
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. 1 to 5.
Since a gear pump body is the same as the conventional one, it is denoted at the same numerals and described hereinafter.
The seal 5 interposed between the gear case 1 and the side plates 4 comprises the projections 5a made of an elastic material such as rubber and projections 5b formed by injection molding of fluorocarbon resin.
The projections 5a comprises annular parts 5.sub.1 for sealing a peripheral portion of a gear chamber 1a housing gears 2 and 3 therein and the side plates 4 and annular parts 5.sub.2 disposed inside the annular parts 5.sub.1 for sealing peripheries of the shaft portions 2a and 3a of the gears 2 and 3 and a pressure balancing high pressure chamber 4a. The projections 5b of fluorocarbon resin is provided at the entire periphery inside the annular parts 5.sub.2.
The projections 5a are close to each other at the part of the
REFERENCES:
patent: 3482524 (1969-12-01), Marietta
patent: 3891360 (1975-06-01), Dworak et al.
patent: 3895890 (1975-07-01), Laumont
Fukui Hiroyuki
Takeda Masahiro
Bertsch Richard A.
Freay Charles
Kabushiki Kaisha Komatsu Seisakusho
Komatsu Zenoah Kabushiki Kaisha
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