The present invention relates to displacement control valves for variably controlling the displacement or pressure of working fluid, and for example, relates to a displacement control valve for controlling the discharge rate of a variable displacement compressor used in an automobile air-conditioning system, according to pressure.
A variable displacement compressor used in an air-conditioning system of an automobile or the like includes a rotating shaft rotationally driven by an engine, a swash plate connected to the rotating shaft at a variable inclination angle, and compression pistons connected to the swash plate. By changing the inclination angle of the swash plate, the variable displacement compressor changes the stroke volume of the pistons to control the fluid discharge rate. Using a displacement control valve that is driven by electromagnetic force to open and close, the inclination angle of the swash plate can be changed continuously by properly controlling pressure in a control chamber while utilizing suction pressure Ps in a suction chamber for sucking fluid, discharge pressure Pd in a discharge chamber for discharging fluid pressurized by the pistons, and control pressure Pc in the control chamber housing the swash plate (see Patent Citation 1).
During continuous driving of the variable displacement compressor (hereinafter, sometimes referred to simply as “during continuous driving”), the displacement control valve, the energization of which is controlled by a control computer, performs normal control of adjusting the control pressure Pc by moving a valve element axially by electromagnetic force generated by a solenoid, opening and closing a main valve, and supplying pressure in the discharge chamber to the control chamber.
During the normal control of the displacement control valve, the pressure in the control chamber in the variable displacement compressor is controlled properly. By continuously changing the inclination angle of the swash plate with respect to the rotating shaft, the stroke volume of the pistons is changed to control the discharge rate of fluid into the discharge chamber to adjust the air-conditioning system to have a desired cooling capacity. When the variable displacement compressor is driven at a maximum capacity, the main valve of the displacement control valve is closed to reduce the pressure in the control chamber, thereby to maximize the inclination angle of the swash plate.
There is known another one that forms an auxiliary communicating passage that allows communication between control ports and suction ports of a displacement control valve so that, at the time of startup, a refrigerant in a control chamber of a variable displacement compressor is discharged through the control ports, the auxiliary communicating passage, and the suction ports into a suction chamber of the variable displacement compressor to quickly reduce the pressure in the control chamber at the time of startup, and thereby to improve the responsivity of the variable displacement compressor (Patent Citation 1).
Patent Citation 1: JP 5167121 B2 (page 7, FIG. 2)
In Patent Citation 1, the fluid discharge function is excellent at the time of startup. However, during the continuous driving of the variable displacement compressor, the refrigerant flows from the control ports into the suction ports since the auxiliary communicating passage connects the ports, increasing the refrigerant flow. This can lead to a reduction in the operational efficiency of the variable displacement compressor.
The present invention has been made with attention focused on this problem, and has an object of providing a displacement control valve having a good operational efficiency while having a fluid discharge function at the time of startup.
In order to solve the foregoing problem, a displacement control valve according to a first aspect of the present invention includes a valve housing formed with a discharge port, a suction port, and a control port, a valve element constituting a main valve that contacts and separates from a main valve seat, for opening and closing communication between the discharge port and the control port by driving force of a solenoid, a pressure-sensitive valve that opens and closes according to ambient pressure, and a pressure-sensitive valve member extending from the valve element to a pressure-sensitive chamber, and constituting the pressure-sensitive valve together with a pressure-sensitive element, the valve element and the pressure-sensitive valve member being formed with an intermediate communicating passage, the intermediate communicating passage allowing communication between the control port and the suction port by opening and closing of the pressure-sensitive valve, in which the pressure-sensitive valve member is formed with a through hole communicating with the intermediate communicating passage, and is provided with a sliding member that slides relatively to the pressure-sensitive valve member by fluid flow produced by opening of the main valve, for opening and closing the through hole.
According to the first aspect, when the main valve is closed at the time of startup and in a maximum energized state, the sliding member is opened to connect the control port and the suction port, so that control pressure can be quickly reduced. On the other hand, when the main valve is controlled in an energized state, the sliding member is closed to cut off connection between the control port and the suction port, so that fluid flow from the control port into the suction port can be prevented. Thus, the variable displacement compressor can be enhanced in the discharge of a liquid refrigerant at the time of startup and operational efficiency.
According to a second aspect of the present invention, the sliding member is preferably formed with a receiving surface facing toward the main valve.
According to the second aspect, the sliding member operates easily by fluid flow produced by the opening of the main valve.
According to a third aspect of the present invention, the receiving surface is preferably inclined with respect to a reciprocating direction of the valve element.
According to the third aspect, fluid easily flows from the discharge port toward the control port by the opening of the main valve.
According to a fourth aspect of the present invention, on a back side of the receiving surface, a biasing member for biasing the sliding member toward the main valve side is preferably disposed.
According to the fourth aspect, the sliding member can be moved by a simple structure.
According to a fifth aspect of the present invention, the sliding member is preferably formed with a vent hole on the main valve side of the opening/closing end portion.
According to the fifth aspect, fluid in a space formed between the sliding member and the pressure-sensitive valve member is allowed to flow in and out, and is less prone to develop a pressure difference between the interior of the space and the pressure-sensitive chamber, so that the sliding member can slide smoothly.
According to a sixth aspect of the present invention, the sliding member is preferably disposed so that the sliding member can move while closing the through hole.
According to the sixth aspect, since the through hole is closed until the sliding member has slid a predetermined distance or more, even when the sliding member is slightly slid by disturbance such as vibration, the through hole can be maintained closed. The displacement control valve is thus resistant to disturbance and excellent in control accuracy.
According to an seventh aspect of the present invention, the valve element and the pressure-sensitive valve member are preferably different bodies, and the valve element is preferably formed with a stopper for restricting movement of the sliding member to the valve element side.
According to the seventh aspect, the sliding of the sliding member can be restricted by a simple structure.
According to a eighth aspect of the present invention, the through hole is preferably one of a plurality of through holes formed in the pressure-sensitive valve member.
According to the eighth aspect, a large flow path cross-sectional area can be provided.
A mode for carrying out a displacement control valve according to the present invention will be described below based on embodiments.
A displacement control valve according to a first embodiment will be described with reference to
A displacement control valve V of the present invention is incorporated in a variable displacement compressor M used in an air-conditioning system of an automobile or the like, and variably controls the pressure of working fluid as a refrigerant (hereinafter, referred to simply as “fluid”), thereby to control the discharge rate of the variable displacement compressor M to adjust the air-conditioning system to have a desired cooling capacity.
First, the variable displacement compressor M will be described. As shown in
The variable displacement compressor M includes a rotating shaft 5 rotationally driven by an engine not shown installed outside the casing 1, a swash plate 6 connected to the rotating shaft 5 in an eccentric state by a hinge mechanism 8 in the control chamber 4, and a plurality of pistons 7 connected to the swash plate 6 and fitted reciprocatably in the respective cylinders 4a. Using the displacement control valve V that is driven by electromagnetic force to open and close, the variable displacement compressor M controls the fluid discharge rate by properly controlling the pressure in the control chamber 4 while utilizing suction pressure Ps in the suction chamber 3 for sucking fluid, discharge pressure Pd in the discharge chamber 2 for discharging fluid pressurized by the pistons 7, and control pressure Pc in the control chamber 4 housing the swash plate 6, continuously changing the inclination angle of the swash plate 6, and thereby changing the stroke volume of the pistons 7. For the sake of explanatory convenience,
Specifically, the higher the control pressure Pc in the control chamber 4, the smaller the inclination angle of the swash plate 6 with respect to the rotating shaft 5, and the stroke volume of the pistons 7 is reduced. Under pressure above a certain level, the swash plate 6 is in a substantially vertical position with respect to the rotating shaft 5 (a position slightly inclined from a vertical position). At this time, the pistons 7 have a minimum stroke volume, and the pistons 7 apply a minimum pressure to fluid in the cylinders 4a, so that the discharge rate of the fluid into the discharge chamber 2 is reduced, and the air-conditioning system has a minimum cooling capacity. On the other hand, the lower the control pressure Pc in the control chamber 4, the larger the inclination angle of the swash plate 6 with respect to the rotating shaft 5, and the stroke volume of the pistons 7 is increased. Under pressure below a certain level, the swash plate 6 is at a maximum inclination angle with respect to the rotating shaft 5. At this time, the pistons 7 have a maximum stroke volume, and the pistons 7 apply a maximum pressure to fluid in the cylinders 4a, so that the discharge rate of the fluid into the discharge chamber 2 is increased, and the air-conditioning system has a maximum cooling capacity.
As shown in
In the present embodiment, the main valve 50 consists of a main-secondary valve element 51 serving as a valve element, and a main valve seat 10a formed at an annular protrusion 10c of an isosceles trapezoidal shape in a cross-sectional view protruding from an inner peripheral surface of a valve housing 10 to the inside-diameter side. The axially left end 51a of the main-secondary valve element 51 contacts and separates from the main valve seat 10a. The secondary valve 54 consists of the main-secondary valve element 51 and a secondary valve seat 82a formed at an opening end face (an axially left end face) of a fixed core 82. A step 51b of the main-secondary valve element 51 on the axially right side contacts and separates from the secondary valve seat 82a. The pressure-sensitive valve 53 consists of an adapter 70 of a pressure-sensitive element 60 and a pressure-sensitive valve seat 52a formed at the axially left end of a pressure-sensitive valve member 52. The axially right end 70a of the adapter 70 contacts and separates from the pressure-sensitive valve seat 52a.
Next, the structure of the displacement control valve V will be described. As shown in
As shown in
The casing 81 is formed with a recess 81b recessed axially rightward from the radial center of the axially left end. In the recess 81b, an axially right end portion of the valve housing 10 is inserted and fixed.
The fixed core 82 is formed from a rigid body of a magnetic material such as iron or silicon steel, and includes an axially extending cylindrical portion 82b formed with an insertion hole 82c into which the drive rod 83 is inserted, and an annular flange 82d extending in the outside-diameter direction from an outer peripheral surface of an axially left end portion of the cylindrical portion 82b, and is formed with a recess 82e recessed axially rightward from the radial center of the axially left end of the cylindrical portion 82b.
As shown in
In the valve housing 10, a main valve chest 20 in which the axially left end 51a side of the main-secondary valve element 51 is disposed, a secondary valve chest 30 formed on the back-pressure side (the axially right side) of the main-secondary valve element 51, and the pressure-sensitive chamber 40 formed in a position opposite to the secondary valve chest 30 relative to the main valve chest 20 are formed. The secondary valve chest 30 is demarcated by the outer peripheral surface of the main-secondary valve element 51 on the back-pressure side, the opening end face (the axially left end face) and the recess 82e of the fixed core 82, and the inner peripheral surface of the valve housing 10 on the axially right side of the guide surface 10b.
In the valve housing 10, Pd ports 12 serving as discharge ports for connecting the main valve chest 20 and the discharge chamber 2 of the variable displacement compressor M, Ps ports 13 serving as suction ports for connecting the secondary valve chest 30 and the suction chamber 3 of the variable displacement compressor M, and Pc ports 14 serving as control ports for connecting the pressure-sensitive chamber 40 and the control chamber 4 of the variable displacement compressor M are formed.
As shown in
The pressure-sensitive element 60 is disposed in the pressure-sensitive chamber 40, and operates to provide a resultant force of a biasing force to move the adapter 70 axially rightward and an axially rightward biasing force on the main-secondary valve element 51 and the pressure-sensitive valve member 52 according to the suction pressure Ps in the secondary valve chest 30, which serves as ambient fluid pressure, thereby causing the axially right end 70a of the adapter 70 to be seated on the pressure-sensitive valve seat 52a of the pressure-sensitive valve member 52. When the suction pressure Ps in an intermediate communicating passage 55 is high, the pressure-sensitive element 60 contracts under ambient fluid pressure, operating to separate the axially right end 70a of the adapter 70 from the pressure-sensitive valve seat 52a of the pressure-sensitive valve member 52, and thereby opening the pressure-sensitive valve 53, which is not shown for the sake of explanatory convenience. Thus, when the suction pressure Ps in the secondary valve chest 30 is high, for example, the control pressure Pc can be quickly released through the intermediate communicating passage 55 and a plurality of through holes 51c in the main-secondary valve element 51 into the secondary valve chest 30.
As shown in
As shown in
The axially left end of the coil spring 91 abuts a side surface 52g of the mounting portion 52b extending in the outside-diameter direction from the axially left end, and the axially right end of the coil spring 91 abuts an inner surface (an annular surface 90f described later) of the sliding member 90 externally fitted on the mounting portion 52b and the sliding contact portion 52c of the pressure-sensitive valve member 52, biasing the sliding member 90 to the axially right side (the main valve 50 side). The coil spring 91 is a compression spring, and its outer periphery is radially at a slight distance from the inner peripheral surface of the sliding member 90. Furthermore, the outer periphery of the coil spring 91 may be guided by the inner peripheral surface of the sliding member 90, and the inner periphery of the coil spring 91 may be radially at a slight distance from the outer peripheral surface of the pressure-sensitive valve member 52 (the mounting portion 52b).
As shown in
The sliding member 90 has the inside formed in a stepped cylindrical shape in which the inside diameter of the second cylindrical portion 90c is larger than that of the first cylindrical portion 90a, and formed with the annular surface 90f that extends in the outside-diameter direction from the axially left end of the inner peripheral surface of the first cylindrical portion 90a and intersects at right angles to be continuous in an axial position corresponding to substantially the axial center of the tapered portion 90b (the receiving surface 90e). That is, the annular surface 90f is formed on the back side (the inner peripheral side) of the receiving surface 90e. Note that the inner peripheral surface of the first cylindrical portion 90a and the outer peripheral surface of the mounting portion 52b of the pressure-sensitive valve member 52, and the inner peripheral surface of the second cylindrical portion 90c and the outer peripheral surface of the sliding contact portion 52c of the pressure-sensitive valve member 52 are arranged radially at a slight distance from each other, thereby forming a minute gap between them. Thus, the sliding member 90 can relatively move axially smoothly to the pressure-sensitive valve member 52.
The sliding member 90 is formed, at the axially right end thereof, that is, the axially right end of the first cylindrical portion 90a, with an end face portion 90g that abuts a stopper 51d at an axially left end face of the main-secondary valve element 51 when the through holes 52d in the pressure-sensitive valve member 52 are opened by the opening/closing end portion 90d (see
Note that the through holes 52d in the pressure-sensitive valve member 52 are formed on the axially right side of the axially left end (the side surface 52h) of the sliding contact portion 52c. Thus, until the end face 90h at the axially left end of the sliding member 90 (the opening/closing end portion 90d) has moved from the state of abutting the side surface 52h of the pressure-sensitive valve member 52 to the axial position of the axially left-side opening edge of the through holes 52d, the opening/closing end portion 90d is radially placed on the through holes 52d, maintaining the through holes 52d closed.
Next, operation, mainly the operation of an opening/closing mechanism for the through holes 52d in the pressure-sensitive valve member 52 by the sliding member 90 at the time of startup and during normal control will be described in this order.
First, the operation at the time of startup will be described. After the variable displacement compressor M has been left unused for a long time, the discharge pressure Pd, the control pressure Pc, and the suction pressure Ps are substantially in equilibrium. In the displacement control valve V in a non-energized state, the movable core 84 is pressed axially rightward by the biasing force of the coil spring 85 constituting a part of the solenoid 80, so that the drive rod 83, the main-secondary valve element 51, and the pressure-sensitive valve member 52 move axially rightward, the step 51b of the main-secondary valve element 51 on the axially right side is seated on the secondary valve seat 82a of the fixed core 82, closing the secondary valve 54, and the axially left end 51a of the main-secondary valve element 51 is separated from the main valve seat 10a formed at the inner peripheral surface of the valve housing 10, opening the main valve 50. At this time, the sliding member 90 is located axially rightward, opening the through holes 52d in the pressure-sensitive valve member 52.
By starting the variable displacement compressor M and bringing the displacement control valve V into an energized state, the main valve 50 is closed and the secondary valve 54 is opened. As shown in
Next, the operation during the normal control will be described. During the normal control, under duty control by the displacement control valve V, the degree of opening and the opening time of the main valve 50 are adjusted to control the flow rate of fluid from the Pd ports 12 to the Pc ports 14. At this time, the sliding member 90 receives at the receiving surface 90e the flow of fluid from the Pd ports 12 to the Pc ports 14 produced by the opening of the main valve 50 (shown by a solid-line arrow in
When the variable displacement compressor M is driven at a maximum capacity, by bringing the displacement control valve V into a maximum-duty energized state, the main valve 50 is closed, and the sliding member 90 is moved axially rightward to open the through holes 52d in the pressure-sensitive valve member 52 to allow communication between the control chamber 4 (the Pc ports 14) and the suction chamber 3 (the Ps ports 13). Thus, the control pressure Pc can be quickly reduced. This enables the pistons 7 in the cylinders 4a in the control chamber 4 to vary rapidly, thereby enhancing operational efficiency while maintaining the maximum capacity state.
Under duty control by the displacement control valve V, the degree of opening and the opening time of the main valve 50 are adjusted to control the flow rate of fluid from the Pd ports 12 to the Pc ports 14, and the axially leftward movement of the sliding member 90 is then adjusted, so that the degree of opening of the through holes 52d in the pressure-sensitive valve member 52 can be adjusted by the opening/closing end portion 90d of the sliding member 90. Thus, the flow rate of fluid from the control chamber 4 (the Pc ports 14) to the suction chamber 3 (the Ps ports 13) can be controlled.
In the displacement control valve V in the non-energized state, the receiving surface 90e of the sliding member 90, which faces axially rightward (toward the main valve 50), thus receives the flow of fluid from the Pd ports 12 to the Pc ports 14 produced by the opening of the main valve 50, causing a force to move the sliding member 90 axially leftward to easily act on the sliding member 90. The sliding member 90 thus operates easily.
In the displacement control valve V in the non-energized state, the receiving surface 90e of the sliding member 90, which is inclined with respect to the reciprocating direction of the main-secondary valve element 51 and the sliding member 90, thus facilitates the production of fluid flow from the Pd ports 12 to the Pc ports 14 by the opening of the main valve 50.
In the valve housing 10, the sliding member 90 has the outer peripheral surface of the first cylindrical portion 90a and the tapered portion 90b disposed along and in proximity to the inner peripheral surface of the annular protrusion 10c at which the main valve seat 10a constituting a part of the main valve 50 is formed, thus forming a relatively narrow flow path between the main valve chest 20 and the pressure-sensitive chamber 40. Consequently, by the opening of the main valve 50, fluid flow from the Pd ports 12 to the Pc ports 14 is produced more easily.
Since the coil spring 91 for biasing the sliding member 90 axially rightward (toward the main valve 50) is disposed on the back side (the inner peripheral side) of the receiving surface 90e of the sliding member 90, the sliding member 90 can be axially reciprocated by a simple structure.
Since the sliding member 90 can maintain the through holes 52d in the pressure-sensitive valve member 52 closed by the opening/closing end portion 90d until the sliding member 90 has slid axially rightward a predetermined distance or more from the state where the end face 90h abuts the side surface 52h of the pressure-sensitive valve member 52, even when the sliding member 90 is slightly slid by disturbance such as vibration, the through holes 52d in the pressure-sensitive valve member 52 can be maintained closed. Therefore, the displacement control valve V is resistant to disturbance, and excellent in control accuracy.
Since the main-secondary valve element 51 and the pressure-sensitive valve member 52 are different bodies, and the main-secondary valve element 51 is formed with the stopper 51d for restricting the axially rightward movement of the sliding member 90, the axial movement of the sliding member 90 can be restricted by a simple structure.
The plurality of through holes 52d is formed in the pressure-sensitive valve member 52, and thus can provide a large flow path cross-sectional area for discharging fluid from the control chamber 4 (the Pc ports 14) into the suction chamber 3 (the Ps ports 13). Since the through holes 52d are spaced circumferentially evenly, the stroke of the sliding member 90 can be shortened.
Next, a displacement control valve according to a second embodiment will be described with reference to
A displacement control valve V in the second embodiment will be described. As shown in
As shown in
This causes fluid in the space formed between the sliding member 190 and the pressure-sensitive valve member 152 to flow into and out of the pressure-sensitive chamber 40 through the vent hole 192 with the reciprocation of the sliding member 190 (shown by a dotted-line arrow in
Although the embodiments of the present invention have been described above with reference to the drawings, a specific configuration thereof is not limited to the embodiments. Any changes and additions made to them without departing from the scope of the present invention are included in the present invention.
For example, the embodiments have described the sliding member as one that axially reciprocates relatively to the pressure-sensitive valve member. The sliding member is not limited to this, and may be one that axially reciprocates relatively to the pressure-sensitive valve member while rotationally sliding thereon.
The example where the main-secondary valve element 51 and the pressure-sensitive valve member 52 are formed in different bodies has been described. Alternatively, the two may be formed in a body.
The receiving surface of the sliding member may be formed to be at right angles to the reciprocating direction of the main-secondary valve element 51 and the sliding member.
The sliding member may be reciprocably guided by the adapter 70.
The communicating passage directly connecting the control chamber 4 and the suction chamber 3 of the variable displacement compressor M and the fixed orifice do not necessarily need to be provided.
In the above embodiments, the secondary valve does not necessarily need to be provided. The step on the axially right side of the main-secondary valve element only needs to function as a support member for receiving axial load, and does not necessarily need to have a sealing function.
The secondary valve chest 30 may be provided axially opposite the solenoid 80, and the pressure-sensitive chamber 40 may be provided on the solenoid 80 side.
The coil spring 91 is not limited to a compression spring, and may be a tension spring, or may be of a shape other than a coil shape.
The pressure-sensitive element 60 may not have the coil spring inside.
In the first embodiment, the vent hole 192 in the second embodiment may be provided.
Number | Name | Date | Kind |
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8079827 | Iwa et al. | Dec 2011 | B2 |
20120198992 | Futakuchi | Aug 2012 | A1 |
20170363074 | Taguchi | Dec 2017 | A1 |
Number | Date | Country |
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5167121 | Mar 2013 | JP |
WO-2011065693 | Jun 2011 | WO |
Entry |
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WO2011065693 translation (Year: 2020). |
Number | Date | Country | |
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20200191139 A1 | Jun 2020 | US |