DE60301775T2 - Control valve for a compressor of variable displacement - Google Patents

Description

The The invention relates to a capacity control valve according to the preamble of claim 1, in particular for a variable-capacity compressor displacement in a cooling rice a car air conditioning system.

In a known car air conditioning system is a compressor with used variable displacement, without the restriction the speed of the compressor driving motor to achieve adequate cooling capacity. The angle of attack of a piston driving swash plate is varied, to change the delivery volume of the compressor. The angle of attack is by introducing a portion of the compressed refrigerant into a gas-tight crankshaft chamber, changing the pressure in the crankshaft chamber changed continuously.

The Amount of introduced into the crankshaft chamber, compressed refrigerant is through a capacity control valve which, for example, in a refrigerant flow path disposed between an outlet chamber and the crankshaft chamber is. The control valve stops the differential pressure between the pressure of the outlet chamber and a Intake chamber pressure at a predetermined value, which is set externally is by means of a value of electric current, the solenoid fed to the control valve becomes. The amount of refrigerant discharged from the compressor is changed the engine speed is not affected. It is a variable-speed compressor displacement known in which a passage extending from an outlet chamber to a crankshaft chamber over the capacity control valve extends as an oil return passage is used to lubricate oil to efficiently introduce into the compressor that contained in the refrigerant is.

One Another known compressor uses an oil separator, which is in the refrigerant contained lubricating oil returns to the crankshaft chamber. The oil separator can in an oil return passage be arranged to refrigerant from the exhaust chamber directly back into the crankshaft chamber, without that with the oil charged refrigerant in an external refrigerant circuit introduce.

One another known compressor (JP-A-2002-213350) has in a take-off passage between the crankshaft chamber and the suction chamber an oil separator on. Separated lubricating oil is introduced into a passage extending from the capacity control valve extends to the crankshaft chamber. From the discharge chamber discharged lubricating oil is then directly and quickly returned to the crankshaft chamber.

at the known variable displacement compressor in which the passage, extending from the outlet chamber over the capacity control valve extends to the crankshaft chamber than the oil return passage used. In order to is it possible to lubricate the oil Crankshaft chamber due to a simple design. however is the amount of recirculated lubricating oil through the set status of the valve opening or opening degree the capacity control valve undesirable influenced. When the valve is fully closed, it is in the Crankshaft chamber no oil returned and Consequently, sufficient lubrication of the compressor is not possible be ensured. This can be a galling of the piston and a Cause the compressor to stop operating. If the oil separator is used, the design of the compressor is considerably complicated and will change the size of the compressor the oil separator undesirable increased.

It is an object of the invention, a capacity control valve for a Compressor with variable displacement specify with which with a simple design in the refrigerant contained lubricating oil efficiently attributable to the crankshaft chamber.

Around the above mentioned Problem solving creates the present invention, a capacity control valve according to claim 1.

There the outlet chamber and the crankshaft chamber interconnecting Communication passage in the valve seat forming member of the Valve in addition is formed between the side of the outlet chamber and the Side of Kurbelwel steering chamber is arranged in the compressor is oil recirculating refrigerant nevertheless by a simple construction in the crankshaft chamber introduced, when the valve element has seated on the valve seat to the Capacity control valve close. The capacity control valve can can be produced at low cost and hardly prone to failure.

embodiments The invention will be described with reference to the drawings. Show it:

1 a longitudinal section of a capacity control valve (first embodiment),

2 an enlarged view of a valve element of the in 1 shown capacity control valve,

3 a central longitudinal section of another capacity control valve (second embodiment),

4 an enlarged view of a valve element of the in 3 shown capacity control valve,

5 a central longitudinal section of another capacity control valve (third embodiment), and

6 an enlarged view of a valve element of the in 5 shown capacity control valve.

The capacity control valve 100 is in 1 disposed in an intermediate portion of a refrigerant flow path extending from an exhaust chamber to a crankshaft chamber within a not-shown variable-displacement compressor, eg, a compressor for an automotive air conditioning system. The capacity control valve 100 controls the amount of refrigerant that is introduced into the crankshaft chamber of the compressor to vary the discharge amount of the compressor.

The capacity control valve 100 comprises a spherical valve element 2 in one in an upper body 1 trained refrigerant flow path. The flow path communicates at one end with the outlet chamber and at the other end with the crankshaft chamber. The upper body includes an inner space communicating with the crankshaft chamber and a press fit member forming a valve seat 3 contains. The upper edge of the upper body 1 is through a sieve 4 covered. The inner space of the sieve 4 communicates with the outlet chamber. A valve bore 5 , which connects the space on the side of the discharge chamber and the space on the side of the crank chamber, is in the valve seat forming member 3 educated. The end of the valve bore located on the side of the crankshaft chamber 5 defines the valve element 2 a valve seat 5a , ??? In the valve seat forming member 3 extends through a through hole 6 , eg parallel with the valve bore 5 , The through hole 6 also connects the spaces on the side of the outlet chamber and on the side of the crankshaft chamber.

The upper body 1 is fitted in an upper opening of a lower body by press-fitting. A piston rod 8th is along the axis of the upper body 1 arranged axially movable and has the same diameter as the valve bore 5 (More specifically, like a portion thereof corresponding to the valve seat 5a on which the valve element 2 is set up). One end of the piston rod 8th lies on the valve element 2 on one side, that of the valve bore 5 turned away. The other end of the piston rod is in an inner space of the lower body 7 exposed. The inner space of the lower body 7 communicates with a suction chamber of the variable displacement compressor. The Kolbentange 8th takes the suction pressure Ps from the suction chamber at the exposed end. A lower opening of the lower body 7 is through a cap 9 locked.

In the lower body 7 are a fixed core 10 and a sleeve 11 a solenoid section arranged. The fixed core 10 has an upper central opening resting on a lower protruding portion of the upper body 1 is screwed on. Along the axis of the fixed core 10 is a shaft 12 used axially movable. An end of the shaft 12 is at the end of the piston rod 8th at. The other end of the shaft 12 is in a moving core 13 fitted. The shaft 12 and the moving core 13 slide together in the axial direction. The sleeve 11 is surrounded by a solenoid winding, which is a coil carrier 14 and a magnet wire coil 15 includes.

Between the moving core 13 and the fixed core 10 is a spring 16 interposed. Another spring 17 is between the end of the moving core 13 that the fixed core 10 turned away, and the bottom of the sleeve 11 arranged.

One at the periphery of the upper body 1 arranged O-ring 18 seals between the area communicating with the discharge chamber and receiving the discharge pressure Pd and the area communicating with the crank chamber and receiving the pressure Pc as soon as the capacity control valve 100 is mounted in the variable displacement compressor. An O-ring 10 on the periphery of the lower body 7 seals between the area receiving the pressure Pc from the crankshaft chamber and the area communicating with the suction chamber and receiving the suction pressure Ps. An O-ring 20 on the periphery of the lower body 7 seals between the area receiving the suction pressure Ps and the atmosphere.

The member forming the valve seat 3 in 2 is shaped so that in it the valve bore 5 and the through hole 6 eg parallel to each other. Both holes 5 . 6 connect the spaces on the side of the outlet chamber and on the side of the crankshaft chamber.

The valve element 2 is in 2 by a valve element holding member 21 held in the lower opening of the valve seat forming member is arranged so that it along the axis of the piston rod 8th can slide to make sure the valve element 2 the valve bore 5 open and close. Between the valve element holding member 21 and the base portion of the valve seat forming limb 3 from a valve element side of the valve element holding member 21 is opposite, is a spring 22 arranged, which the valve element holding member 21 acted in the valve opening direction.

In the capacity control valve 100 of the 1 and 2 the discharge pressure Pd introduced from the discharge chamber acts on the valve element 2 to the left. The suction pressure Ps from the suction chamber acts on the piston rod 8th to the right. An effective pressure-receiving surface of the valve element 2 on which the discharge pressure Pd is received is equal to the pressure receiving area of the piston rod 8th at which the suction pressure Ps is received. Therefore, with the valve element 2 that controls the flow rate of the refrigerant from the discharge chamber to the crankshaft chamber, a differential pressure valve is formed, which senses the differential pressure between the outlet pressure Pd and the suction pressure Ps and operated in response thereto.

When the magnet wire coil 15 no current is supplied, then the outlet pressure Pd presses the valve element 2 on. The capacity control valve 100 is fully open. In the variable displacement compressor, the value of the pressure Pc in the crank chamber is kept close to the discharge pressure Pd. The difference between the pressures acting on both end faces of each piston (one end face facing into the crankshaft chamber, the other end face located in a cylinder for compressing the refrigerant into the outlet chamber) is minimized. The swash plate in the crankshaft chamber is inclined at such pitch angle that minimizes the length of the piston stroke, thereby controlling the variable displacement compressor to operate at a minimum capacity.

When the magnet wire coil 15 a maximum control current is supplied, the movable core 13 through the fixed core 10 attracted and moved to the right. The capacity control valve 100 is fully closed. By maintaining communication between the side of the suction chamber and the side of the crank chamber through a throttle opening, not shown, only refrigerant from the crank chamber is allowed to flow into the suction chamber via the throttle opening, whereby the pressure Pc in the crank chamber except one Value is reduced, which is close to the suction pressure Ps in the suction chamber. The difference between the pressures applied to the opposite end surfaces of each piston is maximized, whereby the swash plate is inclined at such a skew angle that the length of the piston stroke is maximized. As a result, the variable displacement compressor is controlled to operate at maximum capacity.

In the execution of a normal control with a predetermined control current, that of the magnetic wire winding 15 is fed, the movable core 13 with a magnetic force to the fixed core 10 pulled, which corresponds to the size or the value of the control current. The generated force moves the moving core 13 to the right. This force serves as a set value for the valve element 2 , which operates as a differential pressure valve. That's why the capacity control valve feels 100 the differential pressure between the discharge pressure Pd and the suction pressure Ps, and controls the capacity control valve 100 the flow rate of the refrigerant flowing from the discharge chamber to the crank chamber such that the differential pressure is maintained at a differential pressure corresponding to the value set by the current supplied to the solenoid section.

That through the capacity control valve 100 and refrigerant flowing in the variable displacement compressor contains lubricating oil inside the variable displacement compressor for lubrication. The flow path between the discharge chamber via the capacity control valve 100 to the crankshaft chamber also functions as an oil return passage for returning the lubricating oil. Compressed refrigerant discharged from the discharge chamber returns to the crankshaft chamber via the short route without passing through an external refrigerant circuit, allowing the lubricating oil to circulate efficiently from the discharge chamber to the crankshaft chamber, and then through the aforementioned throttle opening from the crankshaft chamber to the suction chamber.

When by pressurizing the solenoid section, the valve element 2 fully on the valve seat 5a is attached, any refrigerant flow from the outlet chamber to the crankshaft chamber would be interrupted, which disabled the function of the flow path as the oil return passage. To avoid this problem, according to the invention an additional communication passage is provided, which allows refrigerant to the crank chamber once the capacity control valve 100 closed is. This additional communication passage is in the valve seat forming member 3 shaped to maintain an oil circulation even when the valve element 2 on the valve seat 5a has set. The additional communication passage is not through the valve element 2 controlled.

In the 1 and 2 has the valve seat forming member 3 the through hole 6 as this communication passage. The through hole 6 extends into 2 eg parallel to the valve bore 5 in the valve seat forming member 3 to connect the space on the side of the exhaust chamber and the space on the side of the crank chamber. The through hole 6 For example, is circular in cross-section, and its cross-sectional area may be smaller than the cross section of the valve bore 5 , When the valve bore 5 has a diameter of, for example, approximately 1.0 to 1.2 mm, it is desirable that the through-hole 6 a diameter of approximately 0.1 to 0.3 mm, in view of, on the one hand, reducing an influence on the compression performance of the compressor and, on the other hand, ensuring a sufficient flow of lubricating oil from the exhaust chamber side to the crankshaft chamber side to simplify processing and to easily maintain the required accuracy.

The through hole 6 forms a refrigerant flow path from the exhaust chamber side to the crankshaft chamber side so as to efficiently return sufficient lubricating oil to the variable displacement compressor even when the capacity control valve 100 closed is.

The above-mentioned configuration can be suitably further used especially when a refrigerant such as CO ₂ is used, which is difficult to mix with lubricating oil. The required circulation of the lubricating oil can then be easily secured without having to use a complicated device such as an oil separator, and can be easily obtained by forming a permanently open aperture through the valve seat forming member 3 , The capacity control valve 100 can then have a small size and a lower failure rate and be manufactured at low cost.

The capacity control valve 200 in the 3 and 4 differs from the first embodiment by the shape of the additional communication passage, which in the valve seat forming member 23 is trained. The additional communication passage extends between the inner space of the screen 4 communicating with the outlet chamber and the internal space of the upper body 1 that communicates with the crankshaft chamber. The member forming the valve seat 23 has a valve hole 25 on, which connects the spaces on the side of the outlet chamber and on the side of the crankshaft chamber. One end of the valve bore 25 on the side of the crankshaft chamber serves as a valve seat 25a for the valve element 2 , The valve seat 25a has at least one notch 25b on, in a portion of the peripheral edge of the valve seat 25a is trained.

In 4 becomes the attached valve element 2 in contact with the valve seat 25a kept, but not in contact with the notch 25b , This will be through the notch 25b created a gap that allows refrigerant containing oil at the valve seat 25a over and to the side of the crankshaft chamber also flows when the valve element 2 on the valve seat 25a is attached.

It is desirable that the size of the notch 25b is small enough to minimize an influence on the compression performance of the variable displacement compressor, and to easily achieve a required machining accuracy, similarly to the communication passage in the first embodiment. When the valve bore 25 has a diameter of approximately 1.0 mm to 1.2 mm, it is desirable to form the notch to have an equivalent with its opening area corresponding to that of a drilled hole having a diameter of approximately 0.1 mm to 0.3 mm, as would be described for the first embodiment.

The capacity control valve 300 in the 5 and 6 differs from the first and second embodiments by the shape of the additional communication passage, which in the valve seat forming member 33 is formed and extends between the spaces of the valve on the side of the outlet chamber and the crankshaft chamber.

The member forming the valve seat 33 has a valve hole 35 on, which connects the spaces on the side of the outlet chamber and on the side of the crankshaft chamber. One end of the valve bore 35 on the side of the crankshaft chamber serves as the valve seat 35a for the valve element 2 , The member forming the valve seat 33 is in the upper opening of the upper body 1 fitted by pressing. An inner wall of the upper opening of the upper body 1 and an upper outer peripheral surface of the valve seat forming member 33 are in contact with each other. In a portion of the upper outer peripheral surface of the valve seat forming member 33 is an example axially extending communication groove 35b educated.

The communication groove 35b in 6 extends between the space communicating with the discharge chamber and the space communicating with the crank chamber. When the valve element 2 on the valve seat 35a Refrigerant flows from the side of the discharge chamber to the side of the crankshaft chamber through the communication groove 35b to introduce lubricating oil into the compressor.

The communication groove 35b can for example have a V-shape or a curved shape, in cross section. It is desirable that the cross-sectional area of one between the communication groove 35b and the inner wall of the upper body 1 gap created is small enough to minimize an influence on the compression performance of the variable displacement compressor, and to easily achieve the required machining accuracy, similar to the communication passages of the first and second embodiments described above.

After forming the valve seat forming member 33 it is possible, there at the upper outer peripheral surface of the communication groove 35b with the same method used in forming a scribe line, so that the manufacturing efficiency is higher than in the first and second embodiments.

It is according to the invention not necessary to provide any special device, with the lubricating oil is returned to the compressor, but it is only necessary to simply have an area of internal training of the capacity control valve accordingly to change. The inventive concept can be applied to any capacity control valve be in a flow channel of one side of the exhaust chamber to one side of the crank chamber having a valve element. This allows the size of the capacity control valve and also with the capacity control valve equipped compressor, and thus contributes to the reduction of Production costs of these components.

at each of the above-described embodiments does that Capacity control valve a control of the differential pressure between the outlet pressure Pd in the discharge chamber and the suction pressure Ps in the suction chamber by. However, the same concept can also be used at a capacity control valve, that carries out such a regulation, that the suction pressure Ps is kept constant. Furthermore, any Valve element can be used, which has a shape of the differs shown spherical shape.

Claims (7)

Capacity control valve ( 100 . 200 , 300 ) for a variable displacement compressor for controlling a refrigerant amount to be introduced from an exhaust chamber in a crank chamber of the compressor to thereby change a capacity of refrigerant discharged from the compressor, characterized in that in a refrigerant passage, which extends between the outlet chamber and the crankshaft chamber, a valve seat-forming member ( 3 . 23 . 33 ) in which an additional communication passage is formed to constantly connect one side of the discharge chamber and one side of the crank chamber, even if the capacity control valve (14) 100 . 200 . 300 ) is in a fully closed state. Capacity control valve according to claim 1, characterized in that the communication passage a through-bore ( 6 ) formed by the valve seat forming member ( 3 ) is formed, preferably in parallel with a valve bore 5 , Capacity control valve according to claim 1, characterized in that the communication passage is a notch ( 25b ) located on a portion of a valve seat ( 25a ) is formed such that a gap is formed when the valve is closed. Capacity control valve according to claim 1, characterized by a holding member ( 1 ) having a press fitting opening communicating between the side of the discharge chamber and the side of the crank chamber and the valve seat forming member (FIG. 33 ) which is fitted in the press-fitting opening by press-fitting, and by the additional communication passage formed by at least one groove (FIG. 35b ), which on an outer peripheral surface of the valve seat forming member ( 33 ) is formed so as to extend from the side of the discharge chamber to the side of the crank chamber. Capacity control valve according to claim 1, characterized by a valve element ( 2 ), which is provided for opening and closing the refrigerant passage such that the valve element ( 2 ) on a valve seat ( 5a . 25a . 35a ), which on the valve seat forming member ( 3 . 23 . 33 ) can be placed from the side of the crankshaft chamber ago, and a solenoid section for applying an axial magnetic force to the valve element ( 2 ). Capacity control valve according to claim 5, characterized by a coaxial with the valve element ( 2 ) arranged piston rod ( 8th ) whose one end is adjacent to the valve element and the other end has a pressure receiving surface which is as large as an effective pressure receiving surface of the valve element ( 2 ), wherein the piston rod receives the suction pressure (Ps) from a suction chamber at its other end. Capacity control valve according to claim 1, characterized in that the capacity control valve in a refrigerant passage between the outlet chamber and the crankshaft chamber of the compressor, a valve seat ( 5a . 25a . 35a ) and a valve element ( 2 ), which in relation to the valve seat between a closed state and Öff variable in opening degrees, including a fully opened status, that in addition to the valve seat ( 5a . 25a . 35a ) the valve seat ( 5a . 25a . 35a ) at least one permanently open communication passage ( 6 . 25b . 35b ) bypasses between a side of the outlet chamber and a side of the valve seat in a crankshaft chamber, and that the cross section of the communication passage is smaller than the free flow cross section between the valve element ( 2 ) and the valve seat ( 5a . 25a . 35a ) in the fully open status.