JP2754400B2 - Variable displacement compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable displacement compressor, and more particularly to a variable displacement compressor with improved start-up performance.

(Prior Art) Conventionally, a pressure working chamber provided in at least one of a pair of side blocks forming a cylinder and communicating with a suction side and a discharge side, and communicating with the suction side through the pressure working chamber to introduce a suction pressure. A control member having a pressure-receiving portion slidably fitted so as to be airtightly partitioned into a low-pressure chamber to be communicated with the discharge side and a high-pressure chamber into which a control pressure corresponding to the discharge pressure is introduced. An opening and closing valve mechanism having a valve body for opening and closing a communication passage communicating the chamber with the suction side, and opening when the pressure on the suction side is equal to or lower than a predetermined pressure to leak the control pressure in the high pressure chamber to the suction side. A variable displacement compressor configured to control the compression start timing by rotating the control member in accordance with the pressure difference between the high pressure chamber and the low pressure chamber to variably control the discharge displacement. For example, it is known from JP-A-62-20688.

(Problems to be Solved by the Invention) In the variable displacement compressor having the above-described configuration, a seal member is attached to a periphery of the pressure receiving portion of the control member, and a substantially uniform interference with the inner wall of the pressure working chamber is provided. The pressure receiving portion is slidable while keeping the first and second spaces airtight.

However, when the compressor is started, the sliding property of the control member from the partial operation position to the full operation position is not sufficient due to the frictional resistance between the seal member and the pressure working chamber, and a rapid increase in the discharge amount occurs. Thus, there is a problem that the desired startability cannot be obtained. Therefore, by providing a bypass passage that directly communicates the discharge side and the high pressure chamber of the pressure working chamber, by providing an on-off valve that opens when the pressure on the discharge side is lower than a predetermined value, in the bypass passage, 2. Description of the Related Art A variable displacement compressor capable of smoothly performing a change from a partial operation state to a full operation state is known, for example, from Japanese Patent Application Laid-Open No. Sho 62-178796.

However, these conventional compressors all have a configuration in which the valve element of the on-off valve mechanism that leaks control pressure from the high-pressure chamber of the pressure working chamber is biased in the valve closing direction by a spring member to close the valve. However, due to the hysteresis of the opening / closing operation of the opening / closing valve mechanism, there are disadvantages that the opening / closing valve mechanism cannot be opened / closed in a timely manner and the leak rate of the control pressure cannot be appropriately adjusted according to the operating state of the compressor. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and at the time of starting a compressor, a control member can be easily rotated to improve startability, and a control pressure for controlling a discharge capacity of the compressor is compressed. It is an object of the present invention to provide a variable displacement compressor capable of improving the variable controllability of the discharge displacement by appropriately adjusting the displacement in accordance with the operation state of the compressor.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a pressure working chamber provided on at least one of a pair of side blocks forming a cylinder and communicating with a suction side and a discharge side; In the pressure working chamber, the working chamber is airtightly divided into a low-pressure chamber communicating with the suction side and introducing a suction pressure and a high-pressure chamber communicating with the discharge side and introducing a control pressure according to the discharge pressure. A control member having a pressure receiving portion fitted slidably,
An opening / closing valve mechanism having a valve body for opening and closing a communication passage communicating the high-pressure chamber and the suction side, and an opening / closing valve mechanism for opening and closing the communication passage in accordance with a change in the suction pressure; and the high-pressure chamber and the low-pressure chamber In the variable displacement compressor in which the control member is rotated in accordance with the pressure difference to control the compression start timing and variably controls the discharge capacity, one end of the variable displacement compressor is in contact with the valve element of the on-off valve mechanism. A plunger that contacts and biases the valve body in a valve closing direction with a biasing force corresponding to the discharge pressure; and a valve that opens when the difference between the discharge pressure and the control pressure is small to increase the discharge pressure to a high pressure in the pressure working chamber. And an on-off valve to be introduced into the chamber.

(Operation) A valve body is provided for opening and closing a communication passage communicating the high pressure chamber of the pressure working chamber with the suction side, and an opening and closing valve mechanism for opening and closing the communication passage according to a change in suction pressure is provided. A plunger, one end of which contacts the valve body and biases the valve body in the valve closing direction with a biasing force corresponding to the discharge pressure, causes the biasing force of the valve body in the valve closing direction to change the discharge pressure. Therefore, the leak flow rate of the control pressure in the high-pressure chamber to the suction side can be appropriately adjusted according to the operating state of the compressor, so that the discharge capacity of the variable displacement compressor can be varied. Controllability is improved. Also, by providing an on-off valve that opens when the difference between the discharge pressure and the control pressure in the high-pressure chamber of the pressure working chamber is small, and that introduces the discharge pressure into the high-pressure chamber, the compressor with a relatively small discharge pressure starts up when the compressor starts. Also, since the control pressure quickly rises and the control member quickly rotates to the full operation position side, the startability of the compressor is improved.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a variable displacement vane compressor according to one embodiment of the present invention, cut at an angle of 45 degrees passing through an axis.

As shown in FIGS. 1 and 2, the variable displacement vane compressor has a cam ring 1 having a substantially elliptical inner peripheral surface 1a.
A cylinder composed of a front side block 3 and a rear side block 4 fixed to both ends of the cam ring 1 so as to close both ends thereof, and a cylindrical rotor 2 rotatably housed in the cylinder. , Front heads 5, fixed to the outer ends of the side blocks 3, 4, respectively.
The rear head 6 and the rotating shaft 7 of the rotor 2 are main components, and the rotating shaft 7 is rotatably supported by bearings 8 and 9 provided on the side blocks 3 and 4 respectively.

A discharge port 5a for the refrigerant gas as a heat medium is provided on the upper surface of the front head 5, and a refrigerant gas inlet is provided on the upper surface of the rear head 6.
6a are formed respectively. Discharge port 5a is front head 5
Discharge chamber defined by the front side block 3
10, the inlet 6a is the rear head 6 and the rear side block 4.
Respectively, and communicates with the suction chamber 11 defined by.

As shown in FIG. 2, two compression spaces 12, 12 are defined between the inner peripheral surface 1a of the cam ring 1 and the outer peripheral surface of the rotor 2 so as to be symmetrically displaced by 180 degrees in the circumferential direction. I have. The rotor 2 is provided with a plurality (e.g., five) to exist at regular intervals vane groove 13 along the radial direction in the circumferential direction, the vanes 14 _{1-14 5} each radially within these vane grooves 13 It is fitted so that it can come and go along.

As shown in FIGS. 1 and 4, the rear side block 4 is provided with a suction port 15 at a symmetrical position deviated by 180 degrees in the circumferential direction. 1, only one suction port 15 is visible in FIG. 1). Each suction port 15 penetrates in the thickness direction of the rear side block 4, and the suction chamber 11 and each compression space 12 communicate with each other via each suction port 15.

In the outer peripheral wall of the cam ring 1, as shown in FIGS. 1 and 2, a plurality of, for example, two discharge ports 16 are symmetrically displaced by 180 degrees in the circumferential direction and are pierced. . A valve stop 17 is provided on the outer peripheral wall of the cam ring 1 having the discharge port 16.
The discharge valve covers 17 having a are fixed by bolts 18 respectively. Discharge valves 19 held on the discharge valve cover 17 side are interposed between the outer peripheral wall of the cam ring 1 and the valve stopper 17a, and each discharge valve 19 opens when receiving discharge pressure. Each discharge port 16 is opened. Further, the cam ring 1 has a communication passage 20 communicating with each discharge port 16 when each discharge valve 19 is opened, and the front side block 3 has a communication passage 21 communicating with the communication passage 20 at 180 degrees in the circumferential direction. It is formed at a substantially symmetrical position deviated. When each discharge port 16 is opened, the compression space 12
The compressed refrigerant gas in the discharge port 16 and the communication passages 20 and 2
1. Discharge is performed sequentially through the discharge chamber 10 and the discharge port 5a.

As shown in FIGS. 1 and 4, the rear side block 4 is provided with an annular recess 22 at the end face on the rotor 2 side, and two pressure working chambers 23 are provided in the annular recess 22 in the circumferential direction. It is provided at a symmetrical position deviated by 180 degrees. In the annular concave portion 22, a ring-shaped control member 24 is fitted so as to be rotatable forward and backward.

The control member 24 is for controlling the compression start timing of each compression space 12, and an arc-shaped notch 25 is provided on the outer peripheral edge at a symmetrical position deviated by 180 degrees in the circumferential direction. . On one side surface of the control member 24, a protruding pressure receiving portion 26 is integrally provided at a symmetrical position deviated by 180 degrees in the circumferential direction, and the pressure receiving chamber 26 causes the inside of the pressure working chamber 23 to be a low pressure chamber 23 _1. They are respectively 2 minutes into a high pressure chamber 23 ₂ and. As shown in FIG. 1, a seal member 27 is attached to the periphery of the pressure receiving portion 26, and the seal member 27 has a double structure of an elastic seal member 27a and a resin seal member 27b. The sealing member 27 is in close contact with a portion other than portions (36, 36 in FIG. 5) of the inner wall of the pressure working chamber 23, which corresponds to a part operating position to be described later, with a predetermined interference. ₁
Gas and the gas in the high pressure chamber 23 ₂ of the inner is made so as not to leak from one another, and as shown in FIG. 4, are provided so as pressure-receiving portion 26 is slidable in each pressure chamber 23 .
Wherein each notch 25, the front end portion 25 ₁ of the rotation direction of the rotor 2 (Figure 2 and counterclockwise FIG. 4) is provided in the 180-degree deviation the symmetrical positions in the circumferential direction. Each low-pressure chamber 23 ₁ is communicated with the suction chamber 11 through the suction port 15, respective low-pressure chamber 23 ₁
A low suction pressure Ps is introduced therein.

On the other hand, one of the high-pressure chamber 23 _2, 23 _2, the orifice 28 and the communication passage 29 provided respectively in the rear side block 4, provided in the cam ring 1 via a control pressure supply port 30 provided on the cam ring 1 It communicates with the communication passage 20.
Each high-pressure chamber 23 ₂ is communicated with each other through a communication passage 31 provided in the rear head 6. Therefore, when each of the discharge ports 16 is opened, the high-pressure refrigerant gas discharged from the compression space 12 is supplied to one of the high-pressure chambers via the discharge port 16, the communication passage 20, the control pressure supply port 30, the communication passage 29, and the orifice 28. together are introduced into 23 _2, via the communication passage 31 is introduced into the other of the high-pressure chamber 23 _2, the control pressure Pc is formed in the high pressure chamber 23 _2.

Also, one of the high-pressure chamber 23 _2, 23 _2, as shown in FIG. 1, the communication passage provided in the rear side block 4 32
And it can communicate with the suction chamber 11 via the opening / closing valve mechanism 33.
The opening and closing valve mechanism 33, the suction chamber to open and close operation in response to the suction pressure Ps in the 11, the suction chamber 11 a control pressure Pc in the high pressure chamber 23 in ₂ when the valve is opened
The bellows 33 which is a pressure responsive part
a, the case 33b, the ball valve element 33c, and the ball valve element 33c
And a spring 33d for urging the valve in the valve closing direction. Bellows 33a
The case 33b is provided in the suction chamber 11 so as to extend and contract, and the case 33b is mounted in a mounting hole 34 provided in the rear side block 4 and communicating with the communication path 32. And this bellows 33
a is reduced when the suction pressure Ps is equal to or more than a predetermined value (for example, 2 kg / cm ² ) set by the adjusting member 33e. At this time, the ball valve element 33c closes the central hole 33f of the case 33b. On the other hand, when the suction pressure Ps is equal to or lower than the predetermined value, the bellows 33a expands, and the ball valve body 33c opens the central hole 33f. At this time, the high pressure chamber 23
_{One of the two} is a communication passage 32, a mounting hole 34, a hole 33g of a case 33b,
It communicates with the suction chamber 11 via a chamber 33h in the case 33b and a central hole 33f of the case 33b. A plunger 37 is fitted in a through hole 39 formed in the rear side block 4, and urges the ball valve body 33c in the valve closing direction by the discharge pressure Pd introduced from the communication passage 20 through the high pressure introduction hole 40. In contact with the valve element 33c.

As shown in FIG. 1, a torsion coil spring 35 is provided in the suction chamber 11. This torsion coil spring 35
Is disposed around the boss portion 4a of the rear side block 4, one end 35a of which is locked to the side surface of the control member 24 as shown in FIG. 4, and the other end 35b is a boss portion as shown in FIG. Locked to 4a.

As shown in FIG. 5, an angle θ (for example, from one end a ₁ to a ₂ ) of the pressure working chambers 22 and 23 (only one is shown)
The area of 20 ゜) is the enlarged inner width part 3 with a large inner wall width.
6,36. The enlarged inner width portions 36, 36 reduce the interference between the pressure receiving portion 26 and the seal member 27 (for example, the enlarged inner width portion 3).
This is to reduce the frictional resistance (0.5 mm for portions other than 6, 36). This is to reduce the frictional resistance, and when the compressor starts up, the pressure receiving part 26 moves smoothly from the partial operating position to the full operating position. It is provided for. In addition, since the frictional resistance decreases, the partly operating extreme position of the pressure receiving portion 26 at the time of low load shifts to the right side in FIG. 5, so that the rotation range of the control member 24 is expanded, and therefore the discharge capacity variable rate ( The rotation range of the control member 24) is increased, and the controllability is improved. In addition, since the control member can be easily rotated from the entire operation position side to the partial operation position side, the set load of the torsion coil spring for urging the pressure receiving portion can be set to be small. Responsiveness can be further improved.

As shown in detail in FIG. 5, a communication hole 38a communicating with the high pressure chamber 23 ₂ is formed in the rear side block, the communication hole 38a
The on-off valve 38 that opens and closes the ball valve element 38c that is displaced between the valve opening position and the valve closing position shown in FIG.
And a spring 38d for urging the ball valve body 38c and the valve opening position side.
And a locking pin 38e for locking the ball valve element 38c at the valve opening position. When the difference ΔP between the discharge pressure Pd and the control pressure Pc is equal to or less than a predetermined value (3 kg / cm ² ), the spring 38d allows the ball valve body 38c to communicate with the communication hole 38.
When a is opened, the set load is set so that the ball valve element 38C closes the communication hole 38a when ΔP is equal to or greater than a predetermined value.

In general, the discharge pressure refrigerant gas amount supplied from the compression space 12 into the high pressure chamber 23 _2, together with the determined by the high-pressure chamber 23 ₂ in the pressure Pc, according to the amount of refrigerant gas discharged from the high pressure chamber 23 ₂ by the opening and closing valve mechanism 33 Regulated. Here, the on-off valve of the present invention
In the conventional configuration shown in Figure 7 without the 38, the cross-sectional area of the communicating passage for supplying the discharge pressure Pd in the high pressure chamber 23 ₂ S, the high pressure chamber 23 ₂ pressure Pc via an on-off valve mechanism 33 from the orifice 28 Assuming that the cross-sectional area of the communication passage (central hole 33f) discharged to the suction chamber 11 is S ', the following equation is established.

If the predetermined value of the suction pressure Ps which is controlled by the opening and closing valve mechanism 33 that is to be, for example, 2 kg / cm ^2, is necessary to the Pc-Ps ≦ 0.2kg / cm ² in the pressure control is normally performed Therefore, Pc must always be controlled to 2.2 kg / cm ² or less (P
c ≦ 2.2 kg / cm ² ). In order to control the pressure within this range, it is necessary to determine the ratio S '/ S of the communication passage cross-sectional area S' to the communication passage cross-sectional area S according to the discharge pressure Pd. For example, when the discharge pressure Pd is relatively high at 14 kg / cm ² , Becomes

Also, when the discharge pressure Pd is relatively low 6 kg / cm ^2, Becomes

Normally, S '/ S ≒ 9 is set in order to ensure the responsiveness of the change from the entire operating position side to the partial operating position side.

When the on-off valve 38 is provided as in this embodiment shown in FIG. 5, and when the cross-sectional area of the communication hole 38a is S ', the following equations are established from the above equations (1) and (2).

The on-off valve 38 opens when the compressor is started or when the load is low, that is, when the discharge pressure is low, for example, when Pd−Pc = ΔP ≦ 3 kg / cm ² . Becomes

Therefore, if the cross-sectional area S ″ of the communication hole 38a is set to about 1.3 times the cross-sectional area S of the communication passage according to the above equation (5), the pressure control is reliably performed.

Next, the operation of the variable displacement vane compressor having the above configuration will be described.

In each compressor 12, refrigerant gas is sucked from the suction chamber 11 into each compression chamber 12 between two successive vanes in the suction stroke through the suction ports 15 and the notches 25, respectively.
When the One rotor rotational direction rear vanes of the vane passes through the front end 25 ₁ of the notch 25, whereby communication between the compression chambers 12 and each intake port 15 between the two vanes is broken The compression stroke starts. The compression start time is delayed as the control member 24 is rotated from the full operation position in FIG. 2 to the partial operation position in FIG. 3, whereby the discharge capacity is continuously reduced. That is, when the control member 24 is partially in the operating position, the front end 25 ₁ of each notch 25 of the control member 24
Is the foremost position in the rotor rotation direction, the compression start timing is the latest, the volume of the refrigerant gas trapped between the two adjacent vanes is minimized, the discharge capacity is minimized, and the control member 24 is fully operated. when in position, each notch 25 front end 25 ₁ rearmost earliest compression start timing is in a position in the rotor rotation direction, the volume of the two refrigerant gas trapped between vanes before and after phase It becomes the maximum and the discharge capacity becomes the maximum. Control member 24 by receiving the resultant force of the urging force of the torsion coil spring 35 and the suction pressure Ps introduced into the low pressure chamber 23 _1, the difference between the control pressure Pc in the high pressure chamber 23 within ₂ to the pressure receiving portion 26 It rotates forward and backward between the full operation position and the partial operation position. That is, when the suction pressure Ps is equal to or higher than the predetermined value, the bellows 33a of the opening and closing valve mechanism 33 is closed in the on-off valve mechanism 33 for the ball valve body 33c to shrink to open the central bore 33f, the high-pressure chamber 23 ₂ The control pressure Pc rises, and the control member 24 rotates to the full operation position side, thereby increasing the discharge capacity. When the discharge pressure Pd is high, the force of the plunger 37 pressing the ball valve body 33c increases, and the value of the suction pressure Ps is controlled to be low. When the suction pressure Ps becomes equal to or less than a predetermined value, the bellows 33a is a ball valve element 33c is opened opening and closing valve mechanism 33 for opening the center hole 33f by expanding the control pressure Pc in the high pressure chamber 23 within ₂ suction chamber The control member 24 partially leaks to the operating position side, and the discharge capacity is reduced. When the discharge pressure Pd is low, the force by which the plunger 37 presses the ball valve body 33c becomes small, and the value of the suction pressure Ps is controlled to be high.

When the compressor is started, the pressure receiving part 26 of the control member 24 is
23, is located at the extreme position on the operating side, but until the discharge pressure Pd reaches a predetermined value, that is, ΔP (= Pd−Pc) is a predetermined value (3 kg / cm
² ) In the following cases, the ball valve element 38c of the on-off valve 38
The valve is in the open position due to the urging force of
Open a, the discharge pressure Pd is introduced into the high pressure chamber 23 ₂ through the communication hole 38a. With the introduction of the discharge pressure Pd, particularly in the case of the present embodiment, the interference of the seal member 27 is small and the frictional resistance is small, so that the pressure receiving portion 26 slides smoothly to the full operation position side.

After the compressor is started, when the discharge pressure Pd reaches a predetermined value and enters a steady operation state, the discharge pressure Pd displaces the ball valve body 38c against the urging force of the spring 38d, and closes the communication hole 38a. High pressure discharge pressure thereby becomes equal to or greater than a predetermined value, is prevented from being introduced into the high pressure chamber 23 _2, the normal pressure control of the discharge pressure Pd from only the orifice 28 is performed.

Therefore, at the time of start-up requiring a quick response from the partial operating position to the entire operating position, the discharge pressure Pd is introduced from both the orifice 28 and the on-off valve 38, so that the control member can smoothly rotate. together is possible, there is no problem that the high-pressure chamber 23 ₂ within the control pressure Pc for the reduction of the sealing property due to such a reduction if you reduce the interference of the seal member 27 does not increase as described above, a reliable control member It can be moved to all operating positions.

In the above embodiment, the on-off valve 38 is connected to the high pressure chamber as shown in FIG.
23 but ₂ provided in direct communication, as shown in FIG. 6, be provided in the communication passage 32 for communicating the high pressure chamber 23 ₂ and the opening and closing valve mechanism 33, the same effect as described above can be obtained.

(Effect of the Invention) As described in detail above, the variable displacement compressor of the present invention
A valve is opened when the difference between the discharge pressure and the control pressure is small, and an on-off valve that introduces the discharge pressure to the high-pressure chamber of the pressure working chamber is provided. The valve can be easily turned to the position side, the startability is improved, and a valve body that opens and closes a communication passage that communicates the high pressure chamber of the pressure working chamber and the suction side is provided according to a change in suction pressure. An opening / closing valve mechanism for opening and closing the communication passage is provided, and a plunger for providing one end to the valve body of the opening / closing valve mechanism to urge the valve body in the valve closing direction with an urging force corresponding to the discharge pressure is provided. The leak flow rate of the control pressure for controlling the discharge capacity of the compressor to the suction side can be appropriately controlled in accordance with the operating state of the compressor, and the variable controllability of the discharge capacity of the compressor is improved.

[Brief description of the drawings]

1 to 6 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a variable displacement vane type compressor cut at an angle of 45 degrees passing through an axis, and FIG. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, showing a state where a control member is in an all-operation position;
FIG. 3 is a sectional view similar to FIG. 2, showing a state where the control member is partially in the operating position, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1, and FIG. FIG. 6 is a schematic diagram of a displacement control mechanism according to a first embodiment of the present invention, FIG. 6 is a view similar to FIG. 5 showing another embodiment of the present invention, and FIG. It is a schematic block diagram. 23 …… Pressurized chamber, 23 ₁ …… Low pressure chamber, 23 ₂ …… High pressure chamber, 24
... Control member, 26 ... Pressure receiving part, 38 ... On-off valve, Pd ... Discharge pressure, Pc ... Control pressure.

Claims (1)

(57) [Claims] 1. A pressure working chamber provided on at least one of a pair of side blocks forming a cylinder and communicating with a suction side and a discharge side, and communicating with the suction side through the pressure working chamber to introduce a suction pressure. A control member having a pressure receiving portion slidably fitted in the pressure operation chamber so as to be airtightly partitioned into a low pressure chamber and a high pressure chamber in which a control pressure according to the discharge pressure is introduced in communication with the discharge side; An opening / closing valve mechanism that has a valve body that opens and closes a communication path that communicates the high-pressure chamber and the suction side, and that opens and closes the communication path according to a change in the suction pressure;
In the variable displacement compressor, the control member is rotated in accordance with a pressure difference between the high pressure chamber and the low pressure chamber to control a compression start timing to variably control a discharge capacity. A plunger, one end of which contacts the valve body of the mechanism and biases the valve body in a valve closing direction with a biasing force corresponding to the discharge pressure, and opens and discharges when a difference between the discharge pressure and the control pressure is small. An on-off valve for introducing pressure into a high-pressure chamber of the pressure working chamber is provided.