Vane type rotary machine

Details Vane type rotary machine Vane type rotary machine

2001-03-07

2003-10-07

Vrablik, John J. (Department: 3748)

Rotary expansible chamber devices

Shaft or trunnion lubrication or sealing by diverted working...

Reexamination Certificate

active

06629829

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a vane rotary machine such as a vane pump or a vane motor, and more particularly to a vane rotary machine suitable for use in applications where a low-viscosity fluid such as water is used as a working fluid.
BACKGROUND ART
FIGS. 15A and 15B
are views showing an example of a structure of a conventional typical vane pump (unbalanced type).
FIG. 15A
is a cross-sectional view taken along line
15
A—
15
A of
FIG. 15B
, and
FIG. 15B
is a cross-sectional view taken along line
15
B—
15
B of FIG.
15
A.
As shown in
FIGS. 15A and 15B
, the vane pump comprises a rotor
85
housed in a cam casing
80
, a plurality of vanes
120
mounted on the rotor
85
and held in contact with an inner surface of the cam casing
80
, a front cover
90
and an end cover
95
surrounding opposite sides of the rotor
85
, a main shaft
110
attached to the rotor
85
and rotatably supported by bearings
100
,
105
such as ball bearings mounted in the front cover
90
and the end cover
95
, a rear cap
115
mounted on the end cover
95
, and a seal (shaft seal)
113
mounted on the front cover
90
. When the rotor
85
is rotated, a fluid drawn from a supply port
81
defined in the cam casing
80
into a space between adjacent ones of the vanes
120
is pumped and discharged into a discharge port
83
.
FIG. 16
is a vertical cross-sectional view showing an example of a structure of a conventional typical floating side plate type vane pump. Those parts of the vane pump in
FIG. 16
which are identical to those shown in
FIGS. 15A and 15B
are denoted by identical reference numerals. In order to reduce the flow rate of fluid leaking from gaps between the side surfaces of the rotor
85
and the front and end covers
90
,
95
of the vane pump shown in
FIGS. 15A and 15B
, the floating side plate type vane pump has pressure side plates
125
,
130
disposed respectively between the rotor
85
and the front cover
90
and between the rotor
85
and the end cover
95
and pressed against the both side surfaces of the rotor
85
by resilient means
127
,
131
such as compression coil springs, with the pressure of the discharged fluid being applied to the rear surfaces of the pressure side plates
125
,
130
by fluid paths
137
,
139
connected to the discharge port
135
.
Depending on the discharged pressure of the pump that is applied to the rear surfaces of the pressure side plates
125
,
130
, the force by which the pressure side plates
125
,
130
are pressed against the side surfaces of the rotor
85
is changed to adjust the rotor side clearances for thereby reducing the flow rate of fluid leaking from rotor side clearances. If a low-viscosity fluid such as water is used as the working fluid, the leakage from the rotor side clearances may possibly be large, and hence the floating side plate type vane pump can preferably be used as it can reduce the flow rate of leakage fluid.
If the structure shown in
FIG. 16
is used as a floating side plate type vane motor, then the port
135
may be used as a high-pressure supply port, and the pressure of the working fluid may be applied to the rear surfaces of the pressure side plates
125
,
130
by the port
135
.
The vane motor is of a structure which is essentially identical to the structure of the vane pump. In the vane pump, the vanes are pressed against the inner surface of the cam casing under centrifugal forces and the pressure of the working fluid. In the vane motor, until the vanes are pushed out under centrifugal forces in a stage where the motor starts rotating, the fluid passes through from the higher-pressure side to the lower-pressure side. Therefore, the vane motor has resilient means for pushing the vanes against the inner surface of the cam casing from the start of operation thereof. While the illustrated structures are of the unbalanced type, balanced-type vane pump and motor also operate substantially in the same manner as the illustrated structures.
In each of the above conventional structures, the main shaft
110
is rotatably supported by the bearings
100
,
105
such as ball bearings. The bearings
100
,
105
usually comprise rolling bearings (ball bearings) in the ordinary case (hydraulic pressure, pneumatic pressure).
The unbalanced vane pump (or motor) suffers the problem of an increased radial load. Particularly, if a low-viscosity fluid such as water is used as the working fluid, then the bearing assembly is liable to be subject to seizure due to a lubrication shortage, and the balls, retainers, or inner and outer races of the bearing assembly are liable to be damaged.
One solution to the above drawbacks is to use sliding bearings
100
A,
105
A (also applicable to the conventional structure shown in
FIG. 16
) as shown in FIG.
17
. However, the solution also suffers the following problems:
For lubricating the sliding bearings, the working fluid is interposed as a lubricating medium between the sliding surfaces of the main shaft
110
and the sliding bearings
100
A,
105
A. If a low-viscosity fluid such as water (tap water) is used as the working fluid, then because of its low viscosity, a mechanical loss due to the friction in the bearing assembly (the bearings
100
A,
105
A and the main shaft
110
) tends to be large. It is complex and difficult to select materials of the bearings
100
A,
105
A and the main shaft
110
for eliminating such a drawback. Depending on the selection of those materials, the mechanical loss may be increased, and there is a possibility that the mechanical efficiency is lowered. In addition, the main shaft
110
, the bearings
100
A,
105
A, or other parts may possibly be damaged due to the heat generated between the main shaft
110
and the bearings
100
A,
105
A.
With the bearings
100
A,
105
A being arranged as shown in
FIG. 17
, liquid reservoirs R are formed as shown in the drawing. If water (tap water) is used as the working fluid, then crevice corrosion is caused in the liquid reservoirs R and the water as the working fluid itself is corroded and degraded, thus causing scales to be clogged in small spaces in the device, and thus suffering a failure or lowering durability.
FIG. 18
is an enlarged cross-sectional view of the seal
113
shown in FIG.
15
B. In the vane rotary machine of the type described above, the seal (shaft seal)
113
is used. Depending on the kind of the seal
113
, it is preferable that an internal seal pressure P be as small as possible in most cases. If the internal seal pressure P is large, then the seal
113
is pressed against the main shaft
110
under a large force to thus generate a mechanical loss due to the friction in this region. In addition, the seal
113
and the main shaft-
110
are frictionally worn, and there is a possibility that their durability is lowered.
In order to suppress the increase in the internal seal pressure P, as shown in
FIG. 19
, it is conceivable to provide a fluid path
150
defined between the bearing
100
and the seal
113
and communicating with a low-pressure supply port (not shown in
FIG. 19
, but see the supply port
81
shown in FIG.
15
A).
If a low-viscosity fluid such as water is used as the working fluid in a rotary machine of the above structure, then a mechanical loss due to the friction between the vanes
120
and rotary slits
87
, between the rotor
85
and the front cover
90
, and between the rotor
85
and the end cover
95
is possibly increased. In order to reduce such a mechanical loss, it has been proposed that the vanes
120
and the rotor
85
are made of ceramics having good slidability in water lubrication or various engineering plastics such as PEEK (polyetheretherketone) or PTFE (polytetrafluoroethylene). It is important that the rotor
85
, in particular, be made of the above materials. In the vane rotary machine, the rotor
85
is displaceable axially of the main shaft
110
in a range of side clearances of the rotor
85
, i.e., the gaps between the rotor
85
and the front cover
90
and between the rotor
85
and the end cover
95
.
However,

Affiliated with

Also associated with

Rating

Vane type rotary machine does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Vane type rotary machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vane type rotary machine will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3140753