JP3112202B2 - Variable displacement swash plate compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a variable displacement swash plate type compressor suitable for use in vehicle air conditioning.

[0002]

2. Description of the Related Art As a conventional variable displacement type swash plate type compressor (hereinafter simply referred to as a compressor), for example, the one shown in FIG. 5 is known. This compressor has a plurality of bores 51 parallel to the axis.
The cylinder block 51 includes a crank chamber 52 formed at a front end of the cylinder block 51 and a front housing 53 joined thereto. A suction chamber 55 and a discharge chamber 56 are formed at a rear end of the cylinder block 51 via a valve plate 54. The rear housing 57 is formed and joined. A drive shaft 59 is rotatably supported by the front housing 53 through a crank chamber 52 through a shaft sealing chamber 58. The drive shaft 59 is rotatably supported by a swash plate 62 via a rotary support 60 and a sleeve 61. Are tiltably supported. The rotation support 6
A thrust bearing 69 is interposed between the front housing 0 and the front housing 53. A swing plate 63 is attached to the swash plate 62 through a thrust bearing 64 in a rotation-restricted state, and a piston 65 disposed in each bore 51 a of the cylinder block 51 has a piston rod. 6
By being moored via 6, the piston 65 can reciprocate in the bore 51a according to the inclination angle of the swing plate 63.

In this compressor, the rotational motion of the drive shaft 59 is converted into the oscillating motion of the oscillating plate 63 via the swash plate 62, and the piston 65 reciprocates in the bore 51a. Bore 5 through suction port 70 of valve plate 54
The refrigerant gas sucked into 1a is discharged to the discharge chamber 56 through the discharge port 71 of the valve plate 54 while being compressed. The suction port 70 and the discharge port 71 are opened and closed according to the reciprocating motion of the piston 65 by the suction reed valve 72 and the discharge reed valve 73, respectively. Then, the stroke of the piston 65 fluctuates according to the pressure difference between the pressure in the crank chamber 52 and the suction pressure in the bore 51a, and the displacement of the displacement is controlled by changing the inclination angle of the swing plate 63. That is, when the pressure in the crank chamber 52 increases and the back pressure acting on the piston 65 increases, the inclination angle of the swinging plate 63 decreases and the discharge capacity decreases. Conversely, the pressure in the crank chamber 52 decreases and the piston When the back pressure acting on the valve 65 decreases, the inclination angle of the swing plate 63 increases, and the discharge capacity increases. The pressure in the crank chamber 52 is controlled based on the suction pressure in the suction chamber 55 by a control valve 67 disposed in the rear end projection of the rear housing 57.

[0004]

By the way, the detection pressure chamber of the control valve 67 is communicated with the suction chamber 55 through the detection pressure passage 74, and the suction pressure in the suction chamber 55 is introduced as the detection pressure. Then, according to the detected pressure, the supply passage 7
The pressure in the crank chamber 52 is controlled by controlling the supply of the discharge pressure from the discharge chamber 56 to the crank chamber 52 via 5, 5. For example, when the detected pressure falls below a set value and the discharge capacity needs to be reduced, the control valve 67 opens the supply passages 75 and 76 to supply the pressure in the discharge chamber 56 to the crank chamber 52. Thus, the pressure in the crank chamber 52 is increased, and the inclination angle of the swing plate 63 is reduced.

However, the flow rate of the refrigerant gas flowing through the suction port 70 is limited mainly by the resistance according to the flow path cross-sectional area of the suction port 70. For this reason, when the flow rate of the refrigerant gas flowing through the suction port 70 reaches the critical flow rate with the increase in the rotation speed of the compressor during the large capacity operation of the compressor, the suction chamber 55
The pressure in the inside does not decrease, and the control signal to be detected by the control valve 67 cannot be changed. On the other hand, the reciprocating inertial force of the piston 65 and the like increases with the rotation plate 6 as the rotation speed increases.
3 works in the direction of increasing the inclination angle. Therefore, during high-speed rotation and large-capacity operation of the compressor, the inclination angle of the swing plate 67 is increased by the inertia force, contrary to the control in which the inclination angle of the swing plate 63 should be reduced to a small capacity. As a result, there is a problem that the capacity becomes uncontrollable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is a technical problem to be solved to make it possible to control the displacement up to a higher rotation range by changing the detection pressure of the control valve. It is.

[0007]

According to a first aspect of the present invention, there is provided a compressor in which a control valve is configured to operate using a pressure in a bore during a suction stroke as a detection pressure.
A compressor according to a second aspect of the present invention that solves the above-mentioned problem is characterized in that a detection pressure chamber of a control valve is communicated with a bore via a pressure detection path opened and closed by a suction valve.

According to a third aspect of the present invention, there is provided a compressor in which a detection pressure chamber of a control valve is opened near a top dead center of a bore and provided with a check valve in the middle thereof. And a detection pressure chamber, which is connected to the bore via a pressure detection path having a bypass communicating with the suction chamber via a throttle. Further, a compressor according to a fourth aspect of the present invention that solves the above-mentioned problem is characterized in that a detection pressure chamber of a control valve is connected to a bore via a pressure detection path that opens to a suction port.

[0009]

The pressure in the suction chamber of the compressor is affected mainly by the critical flow rate of the suction port during high-speed rotation at a large capacity due to the resistance corresponding to the flow path cross-sectional area of the suction port. Will not change accordingly. However, in the compressor according to the first aspect of the present invention, the pressure in the bore during the suction stroke of the piston is directly used as the detected pressure, and the pressure in the crank chamber is changed in accordance with the detected pressure to change the piston angle together with the inclination angle of the swash plate. The displacement is controlled by adjusting the stroke. For this reason, even if the suction chamber pressure does not change due to operation at a large capacity and high speed rotation, the pressure in the bore decreases, and the capacity control up to the high rotation range can be performed as compared with the conventional one that uses the pressure in the suction chamber as the detection pressure. It becomes possible.

In the compressor according to the second aspect of the present invention, the detection pressure chamber of the control valve communicates with the bore through the pressure detection passage opened and closed by the suction valve. And the pressure detection path is shut off during the compression stroke. That is,
Only during the suction stroke of the piston, the suction valve opens the detection pressure path, so that high pressure during the compression stroke in the bore is introduced into the detection pressure chamber, thereby preventing malfunction. For this reason, only the pressure change on the low pressure side in the bore can be accurately grasped as a change in the control signal at the control valve, and the displacement can be controlled up to a high rotation range.

In the compressor according to the third aspect of the present invention, the detection pressure chamber of the control valve is opened near the top dead center of the bore and communicates with the bore through a pressure detection path provided with a check valve in the middle thereof. Are in communication. The check valve opens and closes according to the pressure difference between the bore pressure and the pressure in the detection pressure chamber of the control valve. The pressure difference between the bore internal pressure and the pressure in the detection pressure chamber of the control valve is generated as the bore internal pressure decreases or increases during the piston suction or compression stroke. That is, the check valve opens and closes with the suction or compression stroke of the piston, and thereby the bore and the detection pressure chamber of the control valve are communicated or shut off. When the check valve opens due to a decrease in bore pressure during the suction stroke of the piston, the detection pressure chamber of the control valve communicates with the bore, and the suction pressure in the bore during the suction stroke is transmitted to the detection pressure chamber. be introduced. For this reason, the pressure change on the low pressure side in the bore can be accurately grasped as a change in the control signal at the control valve, and the displacement can be controlled up to a high rotation range. In addition, the pressure detection path is located between the check valve and the detection pressure chamber.
Although a bypass communicating with the suction chamber via the throttle is provided, the amount of leak due to the throttle is small, and the leak from the suction chamber to the detection pressure chamber via the bypass is the above capacity during normal operation. It does not affect control. In other words, when the pressure in the detection pressure chamber becomes too low and the check valve cannot be opened, the same situation is recovered by causing a leak from the suction chamber to the detection pressure chamber.

In the compressor according to the fourth aspect of the present invention, since the detection pressure chamber of the control valve communicates with the bore through the detection path that opens to the suction port, the suction valve opens during the suction stroke of the piston. Then, the suction pressure in the suction port is introduced into the detection pressure chamber of the control valve via the pressure detection path. The suction pressure in the suction port changes to a lower pressure in accordance with a pressure change in the bore during the suction stroke, as compared with the pressure in the suction chamber. As a result, pressure changes in the bore can be accurately detected as changes in the control signal at the control valve, and the displacement can be controlled up to the high rotation range, compared to the conventional system that uses the pressure in the suction chamber as the detection pressure. Becomes

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) A partially cutaway sectional view of a compressor according to the present embodiment is shown in FIG. 1, and a sectional view of a main part is shown in FIG. In the figure,
Reference numeral 1 denotes a cylinder block having a plurality of bores 1a parallel to the axis. A front housing 2 is joined to a front end of the cylinder block 1, and a rear housing 3 is connected to a rear end of the cylinder block via a valve plate 4. Are joined. A drive shaft 6 is provided through a crank chamber 5 formed by the cylinder block 1 and the front housing 2, and the drive shaft 6 is provided to the cylinder block 1 and the front housing 2 via radial bearings 7 and 8. It is rotatably supported.

A shaft sealing chamber 2a is formed between the front housing 2 and the drive shaft 6 on the front side of the radial bearing 7, and the front housing 2 and the drive shaft 6 are formed in the shaft sealing chamber 2a.
And a sealing member 9 that seals a gap formed between the first and second members. A rotary support 13 formed so as to surround the drive shaft 6 is fixed to the drive shaft 6 in the crank chamber 5, and the front side of the rotary support 13 is in front of the front housing 2 via a thrust bearing 14. It is rotatably supported on the wall. The rotary support 13 has a support arm 15 extending to the rear surface side, and a counterweight 16 is formed at a position axially symmetric with the support arm 15 so as to maintain rotational stability. A pin 17 is slidably fitted in a long hole 15 a penetrating the distal end of the support arm 15, and a swash plate 18 is tiltably connected to the pin 17.

The drive shaft 6 is adjacent to the rear end of the rotary support 13.
A sleeve 20 is loosely fitted in the swash plate 18.
The swash plate 18 is inserted into an engagement hole (not shown).
It is supported so that it can swing around 0a. A swing plate 23 is supported by the swash plate 18 via a thrust bearing 22 and the like so as to be relatively rotatable. A guide pin 24 is fitted into the lower part of the swinging plate 23 so as to be relatively movable in the radial direction, and the spherical tip part 24 a thereof is connected to the front housing 2.
The rocking plate 23 is restrained from rotating by engaging with a guide groove 25 formed in the inner periphery along the axial direction. A piston 26 disposed in each of the bores 1a of the cylinder block 1 is moored to the swing plate 23 via a piston rod 27. The piston 26 is connected to the bore 1a in accordance with the inclination angle of the swing plate 23. It can reciprocate within.

In the rear housing 3, a suction chamber 28 and a discharge chamber 29 are formed, and a control valve 30 is provided. Further, on both sides of the valve plate 4, a suction valve 32 is disposed on the cylinder block 1 side, and a discharge valve 34 is disposed on the rear housing 3 side. The refrigerant gas in the suction chamber 28 communicating with the refrigeration circuit (not shown) is supplied to the suction port 31 of the valve plate 4.
And is supplied into the bore 1 a through the suction valve 32,
The refrigerant gas compressed by the piston 26 in the discharge chamber 29 through the discharge port 33 and the discharge valve 34 of the valve plate 4.
And is sent out to a refrigeration circuit (not shown). The opening degree of the suction valve 32 is regulated by the cutout groove 1b formed in the cylinder block 1, and the opening degree of the discharge valve 34 is regulated by the retainer 35.

As shown in FIG. 2, a pressure detection passage 40 is formed in the valve plate 4 and the rear housing 3 so as to be openable and closable by a suction valve 32 in the bore 1a. Reference numeral 40 communicates with a detection pressure chamber of the control valve 30 via a pressure detection pipe line 41. The rear housing 3 has a discharge chamber 2
9, a supply passage 42 that communicates with the control valve 30 is formed.
The discharge chamber 29 is supplied through the supply passage 42 and the supply pipe 43.
And the crank chamber 5 are opened and closed by a control valve 30.

In the compressor configured as described above,
With the rotation of the drive shaft 6, the swash plate 1 together with the rotary support 13
8 rotates, the rocking plate 2 moored with each piston 26
The pistons 26 reciprocate in the bores 1 a by sliding the swash plate 18 in the circumferential direction with respect to the swash plate 18. The refrigerant gas is sucked into the bore 1a, and is discharged to the discharge chamber 29 through the discharge port 33 of the valve plate 4 while being compressed. Then, the stroke of the piston 26 fluctuates according to the pressure difference between the pressure in the crank chamber 5 and the suction pressure in the bore 1a, and the displacement angle is controlled by changing the inclination angle of the swing plate 23.

The pressure in the crank chamber 5 is controlled by a control valve 30 disposed in the rear housing 3 based on the cooling load. That is, when the detection pressure detected by the control valve 30 becomes lower than the set value and the discharge capacity needs to be reduced, the control valve 30 opens the supply passage 42 and the supply pipe 43 to release the discharge chamber 29. Is supplied into the crank chamber 5. As a result, the pressure in the crank chamber 5 increases, and the back pressure acting on the piston 26 increases.
The tilt angle of the oscillating plate 23 is reduced, and the discharge capacity is reduced. On the other hand, when the detection pressure detected by the control valve 30 becomes higher than the set value, and it becomes necessary to increase the discharge capacity, the control valve 30 closes the supply passage 42 and the supply pipe 43 and sets the suction chamber. The pressure in the crank chamber 5 decreases and the back pressure acting on the piston 6 decreases due to a relief passage (not shown) communicating the crank chamber 5 and the crank chamber 5. Is increased.

In the compressor of this embodiment, the control valve 3
The zero detection pressure chamber is communicated with the bore 1a via the detection pressure passage 40 and the detection pressure conduit 41, and the pressure detection passage 40 is opened and closed in conjunction with the opening and closing of the suction port 31 by the suction valve 32. For this reason, when the suction valve 32 is opened during the suction stroke of the piston 26, the suction pressure in the bore 1 a is introduced into the detection pressure chamber of the control valve 30 via the detection pressure passage 40 and the detection pressure conduit 41. The bore 1a in the suction stroke of the piston 26
The suction pressure in the inside faithfully changes according to the change in the volume of the bore 1a, and this is the same in a high rotation speed region. For this reason, even when the compressor is operating at a large capacity and at a high speed, the suction pressure in the bore 1a changes and can be accurately detected as a change in the control signal in the detection pressure chamber of the control valve 30. Can be reliably controlled.

(Embodiment 2) In a compressor according to the present embodiment shown in a sectional view of a main part of FIG. 3, a pressure detection passage 40 is formed in a cylinder block 1 so as to open near a top dead center of a bore 1a. A check valve 42 is provided in the middle of a pressure detection pipe line 41 connecting the pressure detection passage 40 and the detection pressure chamber of the control valve 30.
The configuration is the same as that of the first embodiment except that a leak pipe (bypass) 43 is provided in the pressure detection pipe 41 between the control valve 2 and the control valve 30.

The leak pipe 43 communicates with the suction chamber 28 via a throttle means 44. Also, this squeezing means 44
Is small, and the leak from the suction chamber 28 to the detection pressure chamber of the control valve 30 via the leak pipe 43 does not affect the capacity control described below during normal operation. . That is, when the pressure in the detection pressure chamber of the control valve 30 becomes too low and the check valve 42 cannot be opened, the leak pipe 43 and the throttle means 44 move from the suction chamber 28 to the detection pressure chamber. It is a measure taken to remedy the situation by leaking. Such a situation is considered to occur, for example, when the operation is rapidly changed from low-speed rotation to high-speed continuous operation.

In the compressor of this embodiment, the control valve 30
Is communicated with the bore 1a via the pressure detection passage 40 and the pressure detection pipe line 41. The check valve 42 disposed in the middle of the pressure detection pipe line 41 responds to a differential pressure between the pressure in the bore 1a and the pressure in the detection pressure chamber of the control valve 30 which is generated as the pressure in the bore 1a decreases or increases. Open and close. That is, the check valve 42
Opens and closes with the suction or compression stroke of the piston 26,
Thereby, the bore 1a and the detection pressure chamber of the control valve 30 are communicated or shut off. Then, during the suction stroke of the piston 26,
When the check valve 42 is opened due to a decrease in the pressure in the bore 1a, the detection pressure chamber of the control valve 30 communicates with the bore 1a, and the suction pressure in the bore 1a during the suction stroke is introduced into the detection pressure chamber. . For this reason, a pressure change in the bore 1a can be accurately detected as a change in the control signal in the control valve 30, and the displacement can be controlled up to a high rotation range. (Embodiment 3) A compressor according to the present embodiment, which is shown in a sectional view of a main part in FIG. 4, except that a pressure detection passage 40 is formed in a rear housing 3 and a valve plate 4 so as to open into a suction port 31. The configuration is similar to that of the first embodiment.

In the compressor of this embodiment, the control valve 30
Is communicated with the suction port 31 via the detection pressure passage 40 and the pressure detection conduit 41, and when the suction valve 32 is opened during the suction stroke of the piston 26, the pressure detection passage 40 and the pressure detection conduit 4
The suction pressure in the suction port 31 is introduced into the detection pressure chamber of the control valve 30 via 1. The suction pressure in the suction port 31 changes in accordance with the pressure change in the bore 1a even in a high rotation range, as compared with the pressure in the suction chamber 28. For this reason, the pressure change in the bore can be accurately detected as a change in the control signal at the control valve, and the capacity control can be performed up to a high rotation range, as compared with the conventional system in which the pressure in the suction chamber 28 is used as the detection pressure. Becomes possible.

[0025]

As described in detail above, the compressor of the present invention is capable of controlling the pressure change in the bore based on only the volume change in the bore, or the pressure change closer to the pressure change in the bore, to the control valve. Since the displacement is controlled as the detected pressure, it is possible to control the displacement reliably without being affected by the displacement or the number of revolutions of the compressor.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view of a compressor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the compressor.

FIG. 3 is a sectional view of a main part of a compressor according to another embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a compressor according to still another embodiment of the present invention.

FIG. 5 is a partially cutaway sectional view of a conventional compressor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylinder block 1a ... Bore 2 ... Front housing 5 ... Crank chamber 6 ... Drive shaft 18 ... Swash plate 26 ... Piston 28 ... Suction chamber 29 ... Discharge chamber 31 ... Suction port 32 ... Suction valve 40 ... Sensing pressure passage 41 ... Sensing Pressure line 42 ... check valve

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F04B 27/08 F04B 27/14

Claims (4)

(57) [Claims] 1. A cylinder block having a plurality of bores parallel to an axis, a housing connected to one end of the cylinder block by forming a crank chamber, and a rotatable bearing that passes through the crank chamber and is mounted on the housing. Drive shaft, a piston linked to the swash plate cooperating with the drive shaft and reciprocating in the bore, and selectively reciprocating through the bore, each port and each valve means by reciprocation of the piston. A suction valve and a discharge chamber communicating with each other; and a control valve for controlling a pressure in the crank chamber. The control valve changes a pressure in the crank chamber to adjust a piston stroke together with a tilt angle of the swash plate to perform discharge. A variable displacement swash plate compressor having a controlled displacement, wherein the control valve is configured to operate as a detection pressure in a bore during a suction stroke. Quantity type swash plate type compressor. 2. A cylinder block having a plurality of bores parallel to the axis, a housing connected to one end of the cylinder block by forming a crank chamber, and a rotatable bearing that passes through the crank chamber and is mounted on the housing. Drive shaft, a piston linked to the swash plate cooperating with the drive shaft and reciprocating in the bore, and selectively reciprocating through the bore, each port and each valve means by reciprocation of the piston. A suction valve and a discharge chamber communicating with each other; and a control valve for controlling a pressure in the crank chamber. The control valve changes a pressure in the crank chamber to adjust a piston stroke together with a tilt angle of the swash plate to perform discharge. In the variable displacement type swash plate type compressor configured to control a capacity, a detection pressure chamber of the control valve may be communicated with the bore through a pressure detection passage opened and closed by the suction valve. A variable displacement swash plate compressor characterized by the following. 3. A cylinder block having a plurality of bores parallel to an axis, a housing connected to one end of the cylinder block by forming a crank chamber, and a rotatable bearing penetrating through the crank chamber and being mounted on the housing. Drive shaft, a piston linked to the swash plate cooperating with the drive shaft and reciprocating in the bore, and selectively reciprocating through the bore, each port and each valve means by reciprocation of the piston. A suction valve and a discharge chamber communicating with each other; and a control valve for controlling a pressure in the crank chamber. The control valve changes a pressure in the crank chamber to adjust a piston stroke together with a tilt angle of the swash plate to perform discharge. In the variable displacement type swash plate type compressor configured to control the capacity, the detection pressure chamber of the control valve is opened near the top dead center of the bore and provided with a check valve in the middle thereof, and the check valve A variable displacement swash plate type compressor, which is communicated with the bore via a pressure detection path having a bypass communicating with the suction chamber via a throttle between the pressure chamber and the detection pressure chamber. 4. A cylinder block having a plurality of bores parallel to an axis, a housing formed with a crank chamber formed at one end of the cylinder block, and a rotatable bearing that penetrates through the crank chamber and is mounted on the housing. Drive shaft, a piston linked to the swash plate cooperating with the drive shaft and reciprocating in the bore, and selectively reciprocating through the bore, each port and each valve means by reciprocation of the piston. A suction valve and a discharge chamber communicating with each other; and a control valve for controlling a pressure in the crank chamber. The control valve changes a pressure in the crank chamber to adjust a piston stroke together with a tilt angle of the swash plate to perform discharge. In the variable displacement type swash plate type compressor configured to control a capacity, a detection pressure chamber of the control valve is communicated with the bore through a pressure detection path that opens to the suction port. A variable displacement swash plate compressor characterized by the following.