Pumps – Condition responsive control of drive transmission or pump... – Adjustable cam or linkage
Reexamination Certificate
2000-03-06
2002-07-23
Pelham, Joseph (Department: 3742)
Pumps
Condition responsive control of drive transmission or pump...
Adjustable cam or linkage
Reexamination Certificate
active
06422830
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fluid machine for converting fluid energy to mechanical energy or vice versa, such as a compressor for compressing a gas.
2. Description of the Related Art
Regarding this type of fluid machine, a compressor suitable for use for a vehicular air-conditioning system configured, as described below, is known.
Specifically, a crank chamber is defined in a housing, and a drive shaft is rotatably supported by the housing across the crank chamber thereof. In the crank chamber, a swash plate acting as a cam plate is supported on the drive shaft via a rotatable support member to be able to rotate in synchronism with the drive shaft and be inclined with respect to a plane vertical to the axis of the drive shaft. A plurality of pistons are coupled to the outer peripheral portion of the swash plate. A cylinder block constituting a part of the housing is formed with a plurality of cylinder bores, at predetermined spatial intervals, at positions surrounding the drive shaft. The head of each piston is inserted into the corresponding one of the cylinder bores to be able to move reciprocally therein.
When the drive shaft is driven to be rotated by the driving force transmitted thereto, via a belt or the like, from an external drive source such as a vehicle engine, the swash plate is rotated via the rotatable support member synchronously with the drive shaft, and the rotational movement of the swash plate is converted to the reciprocal movement of the pistons. Thus, a compression cycle, including the suction of a refrigerant gas into the cylinder bores, the compression of the refrigerant gas and the discharge of the compressed refrigerant gas from the cylinder bores, is repeated.
A compressor having a mechanism for changing a displacement as described below is also known.
Specifically, a discharge chamber, in which the compressed refrigerant gas stays temporarily, and the crank chamber are in fluid communication with each other through a gas feed passageway having a control valve. The control valve has the function of adjustably changing the opening area of the gas feed passageway and thereby adjusting the amount of the refrigerant gas at high pressure supplied into the crank chamber from the discharge chamber. By adjusting the feeding amount of the refrigerant gas in discharge pressure in this way, the pressure in the crank chamber is changed, so that the difference between the pressure in the crank chamber exerted on one side of the piston and the pressure in the cylinder bore exerted on the other side of the piston is changed. Along with this change of the difference in the pressure, the inclination angle of the swash plate with respect to a plane vertical to the axis of the drive shaft is adjustably changed thereby to adjust the piston stroke, i.e. the amount of displacement.
The compressor described above comprises many sliding portions such as bearings of the drive shaft, the outer surface of each piston and the inner surface of the corresponding cylinder bore, and the coupling between the swash plate and each piston. In the case where foreign matter is caught in any of these sliding portions, the smooth movement of the particular sliding portion is adversely affected, often resulting in an increased load on the external drive source. Especially, seizing on the sliding portion has a serious effect on the external drive source.
Further, in the compressor described above having the mechanism for changing the displacement, foreign matter intruding into the control valve may be caught in the space between a valve body and a valve hole of the control valve so that it may impair the function of adjusting the opening degree of the opening area thereof. Once the function of adjusting the opening degree of the control valve is impaired in this way, the supply of the refrigerant gas in discharge pressure into the crank chamber fails to be adjusted properly, thereby considerably reducing the accuracy of the adjusted displacement.
Another known compressor includes a filter at the inlet of the refrigerant gas into the compressor from an external refrigerant circuit, at the inlet of the gas feed passageway, or at the other locations, in order to avoid troubles which might be caused by the intrusion of foreign matter.
A mounting configuration for one of these filters, which is mounted at the inlet of the gas feed passageway, for example, is illustrated in FIG.
7
.
Specifically, a mounting recess
103
is formed on an inner bottom surface of a discharge chamber
102
defined in an outer peripheral portion of a rear housing
101
, and an inlet to the gas feed passageway
104
opens into the mounting recess
103
. An inner peripheral surface of the mounting recess
103
is formed with a step
105
at the substantially central portion thereof and an annular groove
106
positioned between the opening and the step
105
of the mounting recess
103
. A filter
107
in the form of a circular disk, for example, made of a woven wire, rests on the step
105
and is securely retained there by a snap ring
108
mounted in the annular groove
106
.
with the conventional configuration described above, when mounting the filter
107
at the inlet to the gas feed passageway, at first, it should be dropped onto the step
105
in the mounting recess
103
. Then, after setting the snap ring
108
into registry with the opening of the mounting recess
103
while reducing the diameter thereof by means of pliers or the like, the snap ring should be released from the force of reducing the diameter thereof and thus fitted into the annular groove
106
. Mounting the filter
107
in this way requires skilled work which is difficult to automate and which has to be inevitably performed manually, thereby leading to the problem of a high manufacturing cost for the compressor.
The compressor, whose drive source is the vehicle engine, is generally mounted in the vicinity of the vehicle engine in the engine compartment. Since the space available for arranging the compressor in the engine compartment is limited the demand for a smaller compressor is increasing. A smaller compressor also reduces the size of the opening of the discharge chamber
102
formed with the mounting recess
103
. A space is also required to screw a through bolt for securely coupling the housing of the whole compressor on the outer peripheral portion of the rear housing
101
. This space forms a protruding portion on the inner peripheral surface of the discharge chamber
102
.
On the other hand, a required filtration area sufficient for a predetermined filtering capacity must be maintained. It is therefore difficult to reduce the radial size of the filter
107
. The resulting problem is that the location for the filter
107
to be arranged in the rear housing
101
is severely restricted.
An idea for reducing the radial size of the filter
107
while maintaining a required filtration area is to convexly protrude a portion of the filter
107
along the axis thereof. Protrusion of the filter
107
toward the opening of the mounting recess
103
, however, makes extremely difficult the work of mounting the snap ring
108
. On the other hand, if the filter
107
is protruded toward the bottom of the mounting recess
103
, a new problem arises in that foreign matter is liable to accumulate in the protrusion of the filter
107
.
SUMMARY OF THE INVENTION
The present invention has been developed in order to solve the above-mentioned problems of the prior art and it is an object thereof to provide a fluid machine in which the step of mounting the filter on the flow passageway can be easily automated with an improved latitude of filter arrangement.
In order to achieve the object described above, according to a first aspect of the invention, there is provided a fluid machine which includes a housing assembly provided with a plurality of pressure chambers, a plurality of working chambers for changing a pressure of a fluid accommodating therein to a predetermined level, and a plurality of co
Imanishi Takeshi
Kawaguchi Masahiro
Kumazawa Shingo
Yamada Kiyohiro
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Patel Vinod D
Pelham Joseph
Woodcock & Washburn LLP
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