Rotary expansible chamber devices – Positively actuated vane – Fluid biased
Reexamination Certificate
2001-07-20
2003-10-07
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Positively actuated vane
Fluid biased
C418S270000, C137S540000
Reexamination Certificate
active
06629830
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to pressure adjuster valves, and more particularly to a pressure adjuster valve in which when chamber pressures within the two chambers are reversed, the chamber pressures may be quickly and positively caused to be equal to each other. The present invention also relates to a gas compressor utilizing the pressure adjuster valve.
2. Description of the Related Art
FIG. 6
shows a gas compressor for an automotive air conditioning system. In the same drawing, the gas compressor incorporates therein a pressure adjuster valve
50
as means for preventing the reverse phenomenon of chamber pressures between a suction chamber
11
and a back pressure chamber
23
.
That is, in case of the gas compressor shown in
FIG. 6
, since, upon the operation thereof, the low pressure refrigerant gas within the suction chamber
11
is compressed with in a cylinder
1
and discharged to the side of a discharge chamber
19
as high pressure refrigerant gas, comparing the suction chamber
11
and the back pressure chamber
23
, the suction chamber
11
is lower in chamber pressure than the other chamber. However, in the case where a vehicle is parked for a long period of time at a standstill state in particular under the sunshine in high summer and the like, since the refrigerant gas is soluble in the oil within an evaporator constituting the air conditioning system, the refrigerant gas contained in the oil is warmed by an external air kept at a high temperature and gasified and introduced into the suction chamber
11
side of the gas compressor and the like, under the standstill state before starting the gas compressor, the phenomenon that the chamber pressure within the suction chamber
11
is higher than the chamber pressure within the back pressure chamber
23
, i.e., the so-called reverse phenomenon would occur.
Moreover, in case of a vane rotary type gas compressor as shown in
FIG. 7
, the compression of refrigerant gas is performed by the volume change of a compression chamber
10
inside the cylinder
1
. Also, the pressure of refrigerant gas to be sucked into the cylinder
1
from the suction chamber
11
is applied to work on the tip ends of vanes
9
forming and partitioning the compression chamber
10
.
Accordingly, in accordance with the gas compressor with the structure shown in
FIG. 6
, under the standstill state before the start of the operation, the pressures of the suction chamber
11
and the back pressure chamber
23
are reversed as described above. For this reason, the vanes
9
are pressed back to vane grooves
8
of a rotor
4
by means of the pressure of refrigerant gas within the suction chamber
11
. Therefore, upon the start of the operation, the sealability of the compression chamber
10
partitioned and formed by the vanes
9
and the like is lost, and the compression function of refrigerant gas by the volume change of the compression chamber
10
is degraded, disadvantageously.
Therefore, in the gas compressor shown in
FIG. 6
, the discharge chamber
19
and the back pressure chamber
23
are in communication with each other through an oil feed passage composed of an oil hole
21
, clearances of bearings
5
and
6
and the like. Accordingly, the pressure adjuster valve
50
is provided between the back pressure chamber
23
and the suction chamber
11
as shown in
FIG. 8
so that the reverse phenomenon of the chamber pressures between the back pressure chamber
23
and the suction chamber
11
is prevented.
In case of the pressure adjuster valve
50
shown in
FIG. 8
, when the chamber pressure of the suction chamber
11
is lower than the chamber pressure of the back pressure chamber
23
, a valve body
55
is pressed into a truncated conical hole
52
by means of the pressure difference between the two chambers
11
and
23
to close a communication passage
51
. On the other hand, when the chamber pressures of the two chambers
11
and
23
are reversed, the valve body
55
is released and moved away from the truncated conical hole
52
by means of the pressure difference of the two chambers
11
and
23
. Thus, the pressure of the suction chamber
11
is released to the side of the back pressure chamber
23
through the communication passage
51
and the chamber pressure of the suction chamber
11
is caused to be equal to the chamber pressure of the back pressure chamber
23
.
However, in accordance with the pressure adjuster valve
50
with the conventional structure shown in
FIG. 8
, a gap portion
57
between an edge portion of the truncated conical hole
52
and a surface facing the edge portion is present and the valve body
55
that has been rolled and dropped from the truncated conical hole
52
is partially engaged with this gap portion
57
. Accordingly, even if the chamber pressure of the back pressure chamber
23
is higher than the chamber pressure of the suction chamber
11
, the valve body
55
hardly would be returned in the direction toward the truncated conical hole
52
. Thus, there is a problem that a smooth opening/closing operation of the communication passage
51
could not be ensured.
In order to solve the above-described problem of the pressure adjuster valve
50
shown in
FIG. 8
, there has been an approach that a front portion from the truncated conical hole
52
is formed to extend in the form of a cylinder as the means for eliminating the gap portion
57
. However, in the structure according to this approach, in the case where the oil for lubricating the compressor for lubrication during the operation of the compressor is left within the communication passage
51
even after the standstill of the compressor, an oil film is formed around the valve body
55
so that the valve body
55
is kept stuck to the truncated conical hole
52
by this oil film, or even if the valve body
55
is separated away from the truncated conical hole
52
, in some cases, the communication passage
51
is closed by means of the oil film and the normal function of the pressure adjuster valve
50
is lost. For this reason, even if such a reverse phenomenon of the chamber pressure would take place, it is impossible to immediately cause the pressures to be equal, resulting in the problem of such a reverse phenomenon of the chamber pressures, i.e., the degradation in refrigerant gas compression function during the operation of the compressor.
SUMMARY OF THE INVENTION
In order to solve the above-described problems, an object of the present invention is to provide a pressure adjuster valve that may quickly cause the chamber pressures of the two chambers to be equal to each other with high reliability, when the chamber pressures of the two chambers are reversed, and to provide a gas compressor utilizing the pressure adjuster valve.
In order to achieve the above-mentioned objects, according to the present invention, there is provided a pressure adjuster valve having a communication passage for connecting two chambers, a truncated conical hole provided as a valve seat portion on the way of the communication passage, and a valve body provided to be movable within the communication passage and formed to be engageable with the truncated conical hole, characterized in that:
wherein when a chamber pressure within one of the chambers is lower than a chamber pressure of the other chamber, the valve body is depressed into the truncated conical hole by means of a pressure difference between the two chambers to thereby close the communication passage whereas the chamber pressures of the two chambers are reversed, the valve body is released and moved away from the truncated conical hole by means of the pressure difference between the two chambers upon the reversal to thereby open the communication passage;
the pressure adjuster valve comprises a broadening means for partially broadening a width of a fine gap between the valve body and the communication passage.
According to the present invention, there is provided a pressure adjuster valve having a communication passage for connecting two cha
Kumakura Yasuhide
Osada Muneaki
Takahashi Toru
Adama & Wilks
Denion Thomas
Seiko Instruments Inc.
Trieu Theresa
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