JP3634499B2 - Solenoid control valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic control valve for a variable compressor, and more particularly, to an electromagnetic control valve for a variable capacity compressor used in a vehicle cooling device.
[0002]
[Prior art]
As a displacement control valve of a variable displacement compressor conventionally used, for example, there is an electromagnetic control valve disclosed in Japanese Patent Laid-Open No. 4-119271 shown in FIG. In this electromagnetic control valve, a ball-shaped valve body 102 is urged by a valve spring 103 toward a valve seat 111 formed in the lower portion of the valve body 101, and the movement of the bellows-shaped pressure responsive member 104 is caused by the partition 112. Is transmitted to the valve body 102 by a pressing rod 141 penetrating the valve. The pressure of the fluid introduced from the operating pressure introduction port 113 is applied to the outside of the pressure responsive member 104, and works to compress the pressure responsive member 104. When the fluid pressure decreases, the valve body 102 moves from the valve seat 111. Move away.
[0003]
Further, a pressing member 152 connected to the plunger 105 by a connecting rod 151 provided through the fixed suction element 107 is inserted inside the pressure responsive member 104, and the pressure responsive member 104 is pushed and extended by the plunger spring 106. Is functioning.
[0004]
The connecting rod 151 that connects the plunger 105 and the pressing member 152 is such that when the plunger 105 approaches the fixed suction element 107, the end surface of the pressure responsive member 104 abuts against the surface of the partition wall portion 112, and the plunger 105 and the fixed suction element. The length is adjusted and fixed accurately so that it cannot contact 107, and at this time, the valve opening is maximized.
[0005]
In the conventional electromagnetic control valve having the above configuration, the suction force between the conical surface portion formed between the plunger 105 and the stationary suction element 107 and the flat surface portion works in a balanced manner by energizing the electromagnetic coil 108. Since the plunger 105 moves in the axial direction in proportion to the energization amount in cooperation with the plunger spring 106 and works to push and extend the pressure responsive member 104, the valve body 102 moves in a direction away from the valve seat 111 and is set. The suction pressure value can be increased.
[0006]
With the conventional electromagnetic control valve configured as described above, self-powered control is performed by suction pressure when no power is supplied, and the set suction pressure value can be changed according to the current value that is supplied when current is supplied. be able to.
[0007]
[Problems to be solved by the invention]
However, in the conventional electromagnetic control valve having the above configuration, since the compressor is loaded when the coil is not energized, the compressor starts up from the loaded state when the cooling device is on when the engine is started. It was a configuration that required a burden. Further, although the set suction pressure can be increased by the current value supplied to the coil and the compressor capacity can be reduced, when the suction pressure is increased, the pressure responsive member 104 works in the direction of contraction, contrary to the direction of the suction force. Therefore, in order to perform full unload operation, a large variable suction pressure width, that is, a large coil suction force is required, so that the entire valve becomes large.
[0008]
Therefore, the present invention has been made in view of the above-described conventional problems, and can reduce the burden on the engine when starting the vehicle, reduce the size of the entire valve, and easily change the valve characteristics. An object of the present invention is to provide an electromagnetic control valve that can be used.
[0009]
[Means for Solving the Problems]
The invention according to claim 1 is an electromagnetic control valve, which is disposed in a valve chamber formed by an upper main body as a fixed suction element and a valve main body, and the valve chamber and the valve chamber below the valve chamber A valve body that contacts and separates from a valve seat formed in the valve port in a passage between the valve body and a Pc pressure introduction port that leads to a crank chamber of the compressor, and sandwiches the Pc pressure introduction port of the valve body A Pd pressure introduction port formed on the opposite side of the valve chamber and communicating with the discharge side piping of the compressor; a valve guide communicating between the Pd pressure introduction port and the Pc pressure introduction port;
A valve shaft that is formed integrally with the valve body and is movable in the vertical direction in the valve guide, an urging means for urging the valve body in a valve opening direction, and located above the upper body; A plunger that is movable in the vertical direction by the attractive force of the electromagnetic coil, and biases the valve body in the valve closing direction via a connecting rod that is movable in the vertical direction in the through hole of the upper body;
An internal pressure equalizing hole formed in the valve body and communicating between the valve chamber and the Pd pressure introducing port; and formed below the Pd pressure introducing port of the valve body; A pressure-sensitive adjusting mechanism disposed in a space communicating with the Pd pressure, and a point contact between the lower surface and the upper end of the valve shaft in the Pd pressure introducing port, a contact with the pressure-sensitive adjusting mechanism and the lower end, and the Pd pressure introducing It is characterized by comprising a correction pin that is movable in the vertical direction in a guide hole that communicates between the mouth and the space.
[0010]
The invention according to claim 2 is characterized in that the diameter of the valve guide is made equal to the diameter of the valve port, and the pressure-sensitive adjusting mechanism and the valve body side are separated when the valve body is fully opened.
[0011]
According to the first aspect of the present invention, when the electromagnetic coil is not energized, the valve body is urged in the valve opening direction by the urging means, so that the valve is fully opened. Further, since the internal pressure equalizing hole that communicates between the valve chamber and the Pd pressure introduction port is formed in the valve body, the discharge side pressure Pd of the compressor acts through the internal pressure equalizing hole above and below the valve body. Furthermore, since the correction pin that can move in the vertical direction is provided in the guide hole that communicates between the Pd pressure introduction port and the space in which the pressure-sensitive adjustment mechanism is disposed, the diameter of the correction pin can be changed to change the valve Characteristics can be changed.
[0012]
According to the invention described in claim 2, since the diameter of the valve guide is made equal to the diameter of the valve port, the valve operates regardless of the pressure difference (Pd-Pc) between the discharge side pressure of the compressor and the pressure in the crank chamber of the compressor. When the valve is fully opened, the pressure-sensitive adjustment mechanism and the valve element side are separated.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a displacement control mechanism in a displacement variable compressor used in an automobile. A displacement control electromagnetic control valve 1 is fixed to a mounting recess 40 of the compressor 20.
[0014]
In the compressor 20, a plurality of cylinders 25 are provided in a head portion 41 that is continuous with the crankcase 21, and a piston 26 is slidably provided in each cylinder 25. A drive shaft 27 is rotatably provided from the crankcase 21 to the head portion 41, and the drive shaft 27 is driven by an engine (not shown) by a belt 35 via a pulley 34 provided at an outer end.
[0015]
As is well known, the drive shaft 27 is provided with a variable angle wobble swash plate 29, the wobble swash plate 29 and the piston 26 are connected by a piston rod 24, and the wobble swash plate 29 is rotated by the drive shaft 27 in an inclined state. As a result, the piston rod 24 or the piston 26 reciprocates, and the mounting angle of the wobble swash plate 29 is automatically adjusted according to the differential pressure between the control chamber pressure Pc in the crankcase 21 and the suction side pressure Ps in the cylinder 25. The stroke amount of the piston 26 changes due to a change in the angle of the wobble swash plate 29.
[0016]
Each cylinder 25 is provided with a suction port S and a discharge port D, and a condenser 31, an evaporator 32, and an expansion valve 33 constituting a refrigeration cycle are connected to the cylinder 25 through passages d and s. . Further, the capacity control valve 1 communicates with the control chamber C in the crankcase 21 through the refrigerant passage 36, communicates with the suction port S through the refrigerant passage 37, and further communicates with the discharge port D through the refrigerant passage 38. doing.
[0017]
FIG. 2 shows an electromagnetic control valve 1, which comprises a control valve portion 1a and an electromagnetic proportional control portion 1b.
The valve body 17 is roughly divided into a valve body upper part 17a, a valve body intermediate part 17b, and a valve body lower part 17c.
[0018]
A concave portion is formed in the valve main body upper portion 17a, and a valve chamber 18 is formed by the upper surface 17j thereof and the lower end portion 7b of the upper main body 7, and a valve seat 17d is formed in the valve main body upper portion 17a. Further, a concave portion is formed in the valve main body lower portion 17c, and a bellows chamber 17g joined to the bellows cover 14 located at the lower end portion is formed.
[0019]
A Pc pressure introduction port 17h is provided between the valve body upper part 17a and the valve body intermediate part 17b. The Pc pressure introduction port 17h communicates with the valve chamber 18 through the valve port 17k. Further, a Pd pressure introduction port 17i communicating with the discharge port D of the compressor 20 is formed between the valve body intermediate portion 17b and the valve body lower portion 17c, and this Pd pressure introduction port 17i is connected to the valve chamber 18 and the internal equalization. It communicates with the pressure hole 17q.
[0020]
The bellows chamber 17g of the valve body lower portion 17c communicates with the suction side of the compressor 20 through the Ps pressure introduction port 17s. In addition, accommodating annular grooves 17m, 17n, and 17p for sealing O-rings 42, 43, and 44 are provided on the outer peripheral portions of the valve body upper portion 17a, the intermediate portion 17b, and the lower portion 17c, respectively.
[0021]
A valve portion 8 is provided in the valve chamber 18 so as to face the valve seat 17d, and is biased by the valve spring 9 in a direction away from the valve seat 17d. In addition, a coil suction force acting on the plunger 5 and a biasing force by the plunger spring 4 are applied to the valve portion 8 via a connecting rod 6 positioned above the valve portion 8.
[0022]
In the plunger tube 16, the upper main body 7 and the coil guide 3 as fixed attractors are fixed by welding, and an electromagnetic coil 15 is installed in the outer box 2 so as to surround the plunger tube 16. A plunger 5 is provided in the plunger chamber 19 between the upper body 7 and the coil guide 3 so as to be movable in the axial direction. The plunger 5 has a through hole 5b for communicating with the upper and lower spaces of the plunger 5 in the plunger chamber 19. Is formed.
[0023]
Further, below the plunger 5, a connecting rod 6 is inserted into a guide hole 7 a formed in the center of the upper main body 7 so as to be slidable in the vertical direction, and the upper end 6 a of the connecting rod 6 is the lower surface of the plunger 5. While being in contact with 5a, the lower end 6b is in contact with the upper end surface 8c of the valve portion 8.
[0024]
In the central recess 3 a of the coil guide 3, a plunger spring 4 is provided between the coil guide 3 and the plunger 5, and the plunger 5 is urged toward the valve chamber 18 by the plunger spring 4.
[0025]
The electromagnetic control valve 1 is inserted into the compressor mounting recess 40 until the outer casing 2 comes into contact with the outer surface of the head portion 41. In this state, the Pc pressure introduction hole 17h communicates with the Pc refrigerant passage 36, the bellows chamber 17g communicates with the Ps refrigerant passage 37 via the Ps pressure introduction port 17s, and the Pd pressure introduction hole 17i communicates with the Pd refrigerant passage 38. (FIG. 1).
[0026]
The variable capacity compressor 20 performs an unload operation in which the wobble swash plate 29 stands and the compression stroke is shortened when the control chamber pressure Pc is higher than the suction side pressure Ps, and becomes a full load operation when Pc = Ps pressure. That is, if the pressure control chamber C and the discharge side D are communicated with each other, Pd flows into Pc and a pressure relationship of Pc> Ps is established, and if the pressure control chamber C and the discharge side D are blocked, Pc = Ps. By providing the control valve 1 that adjusts the flow rate of the refrigerant by the suction side pressure Ps between the pressure control chamber C and the discharge side D, the capacity of the compressor 20 can be varied from full load to full unload.
[0027]
Next, the operation of the electromagnetic control valve 1 having the above configuration will be described.
First, as shown in FIG. 3A, the plunger 5 is not attracted to the upper main body 7 when no power is supplied, and the valve portion 8 is moved downward to the plunger spring 4 via the plunger 5 and the connecting rod 6. An urging force and an urging force upward of the valve spring 9 are applied. At this time, since the plunger spring force is smaller than the valve spring force, the valve 1 is fully opened. In this case, the compressor 20 is in the full unload operation state, and in this state, Ps becomes large. Therefore, the bellows 11 that is the pressure-sensitive adjusting mechanism contracts until the bellows guide 12 contacts the bellows cover 14, and the valve shaft 8b. The lower surface of the is separated from the correction pin 10 inserted into the guide hole 17f.
[0028]
Next, when the coil is energized, the attraction force of the coil changes depending on the energized current value, the valve unit 8 becomes an appropriate valve lift, and the compressor 20 is in the capacity control operation state. Here, as shown in FIG. 3B, when the energization current is minimum, the attractive force of the coil becomes equal to or greater than the urging force of the valve spring 9, the connecting rod 6 moves downward, and the valve 1 is slightly closed. . Then, since Ps becomes small, the bellows 11 expands and comes into contact with the correction pin 10, and the force of the bellows 11 acts on the valve portion 8, so that the Ps control region of FIG. 4 is obtained. The Ps value at this time is the minimum energization characteristic of the graph shown in FIG.
[0029]
On the other hand, as shown in FIG. 3C, when the energization current is maximum, the coil attractive force becomes maximum, the valve 1 becomes the Ps control region minimum valve lift, and the Ps value becomes minimum. Further, the Ps value at this time is the maximum energization characteristic of the graph shown in FIG.
[0030]
Here, in the capacity control valve 1 according to the present invention, the balance structure in which Pd acts through the internal pressure equalizing hole 17q above and below the valve body 8a formed so that the diameter of the valve guide 17e is equal to the diameter of the valve port 17k. For this reason, the valve operates regardless of the differential pressure (Pd-Pc), and when the valve is fully opened, the bellows is separated from the valve body side, so that the valve can be operated even if the required suction force of the coil is small. The capacity control valve 1 can be reduced in size.
[0031]
At this time, it is necessary to lower Ps when Pd is higher and to increase Ps when Pd is lower than required characteristics as a control valve (problems such as demist and cool down). Therefore, a correction operation can be performed on the characteristics of the valve by the correction pin 10.
[0032]
The correction pin 10 is in point contact with the lower surface and the upper end of the valve shaft 8b in the Pd pressure introduction port 17i, and a correction differential pressure (Pd-Ps) is applied. Therefore, a correction force is applied to the bellows 11, and this correction is performed. Since the force increases as Pd increases and works in the direction of closing the valve, the Ps high-pressure influence characteristic as shown in the graph of FIG. 4 is obtained. Further, by changing the diameter of the correction pin 10, an arbitrary Ps pressure characteristic can be obtained.
[0033]
【The invention's effect】
According to the first aspect of the present invention, when the electromagnetic coil is not energized, the valve is fully opened, and the compressor is in full unload operation. Therefore, the burden on the engine when starting the vehicle is reduced. In addition, the balance structure in which the discharge side pressure Pd of the compressor acts through the internal pressure equalization holes above and below the valve body, the coil suction force is small, and the entire valve can be downsized. Furthermore, since the high pressure correction of the valve characteristics can be performed by changing the diameter of the correction pin, an electromagnetic control valve that can easily change the valve characteristics can be provided.
[0034]
According to the second aspect of the present invention, the valve operates regardless of the pressure difference (Pd−Pc) between the discharge side pressure of the compressor and the pressure in the crank chamber of the compressor, and when the valve is fully opened, Since the structure separates from the valve body side, the valve can be operated even if the required attractive force of the electromagnetic coil is small, and the entire valve can be downsized.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a capacity control mechanism in a variable capacity compressor in which an electromagnetic control valve according to the present invention is used.
FIG. 2 is a cross-sectional view showing a state when the electromagnetic control valve according to the present invention is not energized.
3 is a cross-sectional view showing the operation of the electromagnetic control valve shown in FIG. 2 when a compressor is mounted, where (a) shows no energization, (b) shows a minimum energization current, and (c) shows an energization current. Indicates the maximum.
FIG. 4 is an explanatory diagram of characteristics of the electromagnetic control valve of FIG. 1;
FIG. 5 is a cross-sectional view showing a displacement control valve of a conventional variable displacement compressor.
[Explanation of symbols]
1 Electromagnetic control valve 2 Outer box 3 Coil guide 4 Plunger spring 5 Plunger 6 Connecting rod 7 Upper body (fixed suction element)
8 Valve portion 8a Valve body 8b Valve shaft 9 Valve spring 10 Correction pin 11 Bellows 12 Bellows guide 13 Bellows spring 14 Bellows cover 15 Electromagnetic coil 16 Plunger tube 17 Valve body 17d Valve seat 17e Valve guide 17g Bellows chamber 17h Pc pressure inlet 17i Pd Pressure inlet 17k Valve port 17q Internal pressure equalizing hole 17s Ps Pressure inlet 18 Valve chamber 19 Plunger chamber 20 Compressor

Claims (2)

A Pc pressure inlet that is arranged in a valve chamber formed by an upper body as a fixed suction element and a valve body, and communicates with the valve chamber and a crank chamber of a compressor formed in the valve body below the valve chamber. A valve body that contacts and separates from a valve seat formed in a valve port in a passage between and
A Pd pressure introduction port formed on the opposite side of the valve chamber across the Pc pressure introduction port of the valve body and communicating with a discharge side pipe of the compressor;
A valve guide communicating between the Pd pressure inlet and the Pc pressure inlet;
A valve shaft formed integrally with the valve body and movable in the vertical direction in the valve guide;
Urging means for urging the valve body in the valve opening direction;
The valve body is closed via a connecting rod which is located above the upper body and can be moved in the vertical direction by the attractive force of the electromagnetic coil and can be moved in the vertical direction in the through hole of the upper body. A plunger biasing in the direction;
An internal pressure equalizing hole that is drilled in the valve body and communicates between the valve chamber and the Pd pressure inlet;
A pressure-sensitive adjusting mechanism formed below the Pd pressure inlet of the valve body and disposed in a space communicating with the suction side of the compressor;
In the Pd pressure introduction port, point contact is made at the lower surface and the upper end portion of the valve shaft, contact is made at the lower end portion with the pressure sensitive adjustment mechanism, and the guide hole communicates between the Pd pressure introduction port and the space. An electromagnetic control valve comprising a correction pin that is movable in the vertical direction. 2. The electromagnetic control valve according to claim 1, wherein the diameter of the valve guide is made equal to the diameter of the valve port, and the pressure-sensitive adjusting mechanism and the valve body side are separated when the valve body is fully opened.

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