JP2707896B2 - Refrigerant gas suction guide mechanism in piston type compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant gas guide mechanism in a piston type compressor.

[0002]

2. Description of the Related Art Generally, an oscillating swash plate type piston compressor has a cylinder block in which a plurality of cylinder bores for accommodating pistons are formed in parallel with each other, and a crank chamber is formed by being joined to a front end surface of the cylinder block. A front housing; and a rear housing joined to a rear end surface of the cylinder block to define a suction chamber and a discharge chamber. The rear housing is provided in the crank chamber by rotation of a rotation shaft supported by a center hole of the cylinder block and the front housing. The piston is reciprocated in a cylinder bore via a drive mechanism having a swinging swash plate, whereby the refrigerant gas sucked from the suction chamber is compressed and discharged to the discharge chamber. More specifically, between the cylinder block and the rear housing, a valve plate passing through a suction hole and a discharge hole, a suction plate having a suction valve for opening and closing the suction hole, and opening and closing the discharge hole are provided. A discharge plate having a discharge valve is provided. And
When the piston is in the suction stroke, the suction valve of the suction plate is opened and the refrigerant gas in the suction chamber is sucked into the working chamber for performing suction and compression in the cylinder bore from the suction hole of the valve plate, and when the piston enters the compression stroke, When the suction valve closes the suction hole and the pressure in the working chamber becomes equal to or higher than a predetermined pressure, the discharge valve of the discharge plate opens, and the compressed refrigerant gas in the working chamber is discharged from the discharge hole of the valve plate to the discharge chamber.

[0003]

In the above-mentioned piston type compressor, lubricating oil is mixed in the refrigerant gas, and this oil adheres to the gap between the contact portion between the plate-shaped suction valve and the valve plate. When the suction valve is elastically deformed against its own elasticity at the beginning of the suction stroke to open the suction hole, the suction force of the oil makes it difficult for the suction valve to separate from the contact surface of the valve plate, thereby performing a suction operation. And the suction pressure of the working chamber in the cylinder bore is reduced more than necessary, which causes a power loss of the compressor.

In order to solve the above problems, the present applicant has proposed a novel refrigerant gas suction mechanism for a compressor different from the prior art. In this suction mechanism, a valve housing chamber communicating with the suction chamber is provided at the center of the cylinder block and the rear housing, and the valve housing chamber and the working chamber in each of the cylinder bores are formed in the cylinder block. The valve accommodating chamber accommodates a rotary valve which is rotated in synchronization with the reciprocating movement of the piston, and a central portion of the rotary valve forms a suction passage which is always in communication with the suction chamber. At the same time, a suction guide groove communicating with the suction communication passage and communicating with the suction passage only in a suction stroke is provided on an outer peripheral surface of the rotary valve in a circumferential direction.

Therefore, when the piston is in the suction stroke due to the rotation of the rotary shaft, the refrigerant gas is sucked into the working chamber from the suction chamber through the gas suction passage of the rotary valve, the suction guide groove and the suction communication passage formed in the cylinder block. To be
The operation of sucking the refrigerant gas is performed smoothly, and it is possible to eliminate the above-mentioned reduction in responsiveness and power loss of the operation of the flat suction valve.

In the rotary valve type suction guide mechanism, when the piston is at the top dead center in the cylinder bore, there is a top clearance in the working chamber in the cylinder bore.
At the initial stage when the piston starts the suction stroke from the top dead center, the compressed gas remaining in the working chamber re-expands and flows back to the suction guide groove side of the rotary valve, causing power loss. In order to prevent this, in the initial stage of the suction operation in which the piston retreats from the top dead center, as shown by a two-dot chain line in FIG. 4, the cylinder bore is prevented from communicating with the suction communication passage and the suction guide groove of the rotary valve. The valve opening timing is delayed by a predetermined angle α so that the suction guide groove and the suction communication passage communicate with each other at the end point P of the re-expansion of the residual gas in the working chamber to start the suction operation.

However, in the suction guide mechanism having such a configuration, the end point P of re-expansion of the residual gas varies depending on the operating conditions of the compressor. , A backflow of gas from the working chamber to the suction communication passage occurs, resulting in power loss, and conversely,
If the end point of the re-expansion is earlier than the valve opening time, the guide groove of the rotary valve and the suction communication passage are rapidly communicated with the working chamber at a negative pressure, so that the refrigerant gas suddenly enters the working chamber. The new inflow causes a large problem of large suction pulsation.

An object of the present invention is to provide a refrigerant gas suction guide mechanism in a piston type compressor which can suppress suction pulsation caused by a rotary valve during a suction stroke and reduce power loss.

[0009]

According to the present invention, in order to achieve the above object, in a piston type compressor, a valve housing chamber communicating with the suction chamber is provided in a housing and / or a cylinder block forming the suction chamber. The valve housing chamber communicates with each of the cylinder bores housing the piston by a suction communication passage. The valve housing chamber houses a rotary valve that is rotated in synchronization with the reciprocating motion of the piston. A suction guide groove is formed on the outer periphery in a circumferential direction so as to communicate with a suction communication passage communicating with a working chamber in a cylinder bore during a suction stroke. Inside the rotary valve, a suction passage constantly communicating the suction chamber with the suction guide groove. And the compressed gas remaining in the top clearance in the cylinder bore is delayed from the point at which The timing is adjusted so that the leading end face located on the leading side in the rotary valve rotation direction of the entrance guide groove corresponds to the gas suction communication passage, and the rotary valve outer peripheral surface or the vicinity of the suction communication passage near the leading end face of the gas suction guide groove. A means for providing a cut-out passage for allowing a small amount of gas to flow in and out from the end of the recompression of the residual compressed gas until the preceding end face corresponds to the suction communication passage on the peripheral surface of the valve accommodating chamber. .

[0010]

According to the present invention, in the suction stroke of the compressor, when the re-expansion end time of the residual gas in the working chamber in the cylinder bore is later than the start time of the suction of the rotary valve by the notched passage, the residual gas is sucked through the notched passage. The gas flows backward from the communication passage to the suction guide groove side of the rotary valve. However, since the amount of gas is small, no power loss occurs.

If the actual end time of the re-expansion of the residual gas is earlier than the start time of the suction of the rotary valve, that is, the start time of the start of the communication between the suction guide groove and the suction communication passage via the notched passage, During the period when the working chamber in the cylinder bore is not communicated with the suction guide groove, the working chamber becomes slightly negative pressure. Immediately thereafter, the working chamber and the suction guide groove communicate with each other by the cutout passage, so that the pressure in the working chamber becomes excessive. Therefore, when the leading end face of the suction guide groove of the rotary valve passes through the suction communication passage and the suction guide groove communicates with the suction communication passage, the gas suddenly flows from inside the rotary valve. No suction is performed into the working chamber, and thus suction pulsation is suppressed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an oscillating swash plate type variable displacement compressor will be described below with reference to FIGS.

A front housing 2 is joined and fixed to a front end surface of the cylinder block 1, and a crank chamber 3 as a drive chamber is formed inside the front housing 2. A rear housing 4 is provided on the rear end surface of the cylinder block 1.
Are fixedly connected via a valve plate 5, a discharge plate 6, and a retainer plate 7. A partition 4a formed inside the rear housing 4 defines a suction chamber 8 at the center and a discharge chamber 9 at the outer periphery. Also, a discharge hole 5a is formed in the valve plate 5, a discharge valve 6a is formed in the discharge plate 6 corresponding to the discharge hole 5a, and a retainer plate 7 regulates an open position of the discharge valve 6a. A retainer 7a is formed.

A rotary shaft 10 is mounted on the cylinder block 1 and the front housing 2 by radial bearings 11,1.
2 and is rotatably supported by external power.
A rotary support 13 is fitted and fixed on the rotary shaft 10 so as to be located in the crank chamber 3. A thrust bearing 14 is interposed between the rotary support 13 and the front housing 2. Further, the rotating support 1
A long hole 13b is formed in the arm portion 13a protruding from the outer periphery of 3, and a rotary swash plate 16 is connected to the long hole 13b via a connecting pin 15 so as to be tiltable in the front-rear direction. A swinging swash plate 17 is rotatably supported on a boss 16 a of the rotating swash plate 16. A pin 19 engages with a sleeve 18 fitted on the rotating shaft 10 so as to reciprocate.
Boss portion 16a is rotatably connected. Further, the swing swash plate 17 is prevented from rotating by a guide rod 20 penetrating and fixed to the cylinder block 1 and the front housing 2, and is allowed to tilt in the front-rear direction.
In this embodiment, the driving mechanism K is constituted by the rotating support 13, the rotating swash plate 16, the swinging swash plate 17, the piston rod 22, and the like.
Is composed.

Pistons 21 are respectively accommodated in cylinder bores 1 a formed at a plurality of positions (five in this embodiment) with respect to the cylinder block 1 in parallel with the rotating shaft 10. Are connected to the swinging swash plate 17 respectively. A spring receiver 23 is mounted on the rotating shaft 10, and a coiled spring 24 is interposed between the spring receiver 23 and the sleeve 18, and the inclination angle of the swash plate 17 always increases, The compression capacity is urged to increase.

The center hole 1b of the cylinder block 1, the center hole 5b of the valve plate 5, the center hole 6b of the discharge plate 6, the center hole 7b of the retainer plate 7, and the inner peripheral surface 4b of the partition 4a of the rear housing 4. A cylindrical valve storage chamber 25 communicating with the suction chamber 8 is formed. The valve chamber 25 and each of the cylinder bores 1a are connected to each other by a plurality of suction communication passages 1c formed in the cylinder block 1. A cylindrical rotary valve 26 for sucking refrigerant gas is rotatably stored in the valve storage chamber 25. An engagement projection 26 a formed on the rear end surface of the rotary shaft 10 is fitted into an engagement hole 26 a formed on the front end surface of the rotary valve 26, and is connected to the rotary shaft 10 by a key 27 so as to be synchronously rotatable. I have. The rear end surface of the rotary valve 26 is restricted in position so that it cannot move rearward by a step 4c formed on the inner peripheral surface of the partition wall 4a.

A suction passage 28 communicating with the suction chamber 8 is formed at the center of the rotary valve 26, and an outer peripheral surface thereof is always in communication with an inner end of the suction passage 28.
A suction guide groove 29 that can communicate with the suction communication passage 1c only during the suction stroke is formed.

Then, the rotating shaft 10 is rotated, and the swinging swash plate 17 is swung back and forth through the rotating support 13, the connecting pin 15 and the rotating swash plate 16, and a plurality of swinging swash plates 17 are moved through the piston rod 22. When the piston 21 is sequentially reciprocated at different timings, the rotary valve 26 is rotated by the rotating shaft 10 and when the piston 21 shifts to the suction stroke, the leading side with respect to the valve rotation direction (see arrow) in FIG. , The leading end face 31 of the suction guide groove 29 passes in a direction to open the suction communication passage 1 c provided in the cylinder block 1.
6, suction guide groove 29 and suction communication passage 1c
Refrigerant gas is sucked into the working chamber 30 in the cylinder bore 1a. At the end of the suction stroke, the rearward end surface 32 of the suction guide groove 29 located on the rear side in the valve rotation direction passes in the direction in which the suction communication passage 1c is closed, and the refrigerant flows into the working chamber 30 in the cylinder bore. Gas intake is stopped. Further, when the rotary shaft 10 and the rotary valve 26 are rotated to move the piston 21 to the discharge stroke, the outer peripheral surface of the rotary valve 26 causes the suction communication passage 1c to move.
Is kept in the closed state, and the refrigerant gas compressed in the working chamber 30 is discharged to the discharge chamber 9 by opening the discharge valve 6a from the discharge hole 5a formed in the valve plate 5.

Although not shown, the rear housing 4 has an opening / closing control valve for opening and closing a communication passage connecting the discharge chamber 9 and the crank chamber 3 and an opening / closing control valve for opening and closing a communication passage connecting the crank chamber 3 and the suction chamber 8. A moment in the front-rear direction acting on the swash plate 17 via the piston rod 22 by adjusting a differential pressure between the pressure in the crank chamber 3 and the pressure in the suction chamber 8 acting on both front and rear surfaces of the piston 21. Is adjusted to change the inclination angle of the swinging swash plate 17 about the connection pin 15, thereby changing the pinton stroke and controlling the compression capacity.

Next, the main part of the present invention will be described.
As shown in FIGS. 3 and 4, during the suction stroke of the compressor, the piston 21 descends from the top dead center, and the compressed gas remaining in the top clearance of the working chamber 30 in the cylinder bore 1 a becomes more predetermined than the end point P of the re-expansion. Delayed by angle θ,
The leading end face 31 of the gas suction guide groove 29 is formed so as to correspond to the gas suction communication passage 1c.
The timing is adjusted so that c is communicated.

The leading end face 3 of the gas suction guide groove 29
A cut-out passage 33 is provided on the outer peripheral surface of the rotary valve 26 near the position 1 so as to allow only a small amount of gas inflow and outflow within the range of the angle θ. The notch passage 33 is configured such that the passage area decreases from the leading end surface 31 to the leading end.

Therefore, in the suction stroke of the compressor, if the end point P of the re-expansion of the residual gas in the working chamber 30 in the cylinder bore is later than the timing of starting the suction of the rotary valve 26 by the notch passage 33, the notch passage 33 is used. The residual gas flows backward from the suction communication passage 1c to the suction guide groove 29 side of the rotary valve 26, but since the gas amount is small,
The power loss is small and not a problem.

Further, the actual end point P of the re-expansion of the residual gas is earlier than the timing of starting the suction of the rotary valve 26, that is, the timing of starting the communication between the suction guide groove 29 and the suction communication passage 1c through the notch passage 33. In this case, the working chamber 30 in the cylinder bore becomes slightly negative pressure in a short period of time when the working chamber 30 in the cylinder bore is not communicated with the suction guide groove 29. And the pressure in the working chamber 30 is prevented from lowering. Therefore, the leading end face 3 of the suction guide groove 29 of the rotary valve 26 is prevented.
When the main suction operation is started corresponding to the suction communication passage 1c, the gas is not suddenly sucked from the suction guide groove 29 into the working chamber 30, so that the suction pulsation is suppressed. .

FIG. 5 shows a cycle diagram at the time of suction / compression operation with the volume of the cylinder bore working chamber 30 taken along the horizontal axis and the pressure in the working chamber 30 taken along the vertical axis. As is clear from this figure, in the conventional example indicated by the two-dot chain line, when the actual residual gas expansion end point P is earlier and the rotary valve 26 is opened considerably later than that, the total area in the cycle is reduced. It is clear that the power loss increases. On the other hand, in this embodiment, as shown by the solid line in FIG. 5, since a large pressure drop does not occur at the beginning of the suction stroke, the entire area in the cycle is reduced, and power loss is suppressed.

The present invention is not limited to the above embodiment, but can be embodied as follows. (1) As shown in FIG. 6, a cutout passage 33 having the same width is formed in the suction gas guide groove 2 from the tip with respect to the outer peripheral surface of the rotary valve 26.
Forming so that it goes deeper toward 8.

(2) As shown in FIG. 7, a notch passage 34 is provided on the cylinder block side. (3) The valve storage chamber 25 is formed only on the cylinder block 1 side or only on the rear housing 4 side.

(4) In addition to the swash plate type variable displacement compressor,
For example, embodied in a swash plate type piston compressor of a constant capacity type.

[0028]

As described above in detail, the present invention can suppress the pulsation of the suction of the refrigerant gas from the suction chamber to the working chamber in the cylinder bore when the rotary valve rotates, and can reduce the abnormal pressure drop in the cylinder bore. And the power loss can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment in which the present invention is embodied in an oscillating swash plate type variable displacement compressor.

FIG. 2 is a perspective view of a rotary valve.

FIG. 3 is a cross-sectional view showing a housed state of a rotary valve.

FIG. 4 is a graph showing a relationship among a rotation angle of a rotary valve, a pressure in a working chamber, and a valve opening.

FIG. 5 is a cycle diagram showing the relationship between the volume in the working chamber and the pressure in the working chamber.

FIG. 6 is a perspective view of a rotary valve showing another embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a rotary valve assembly structure according to another embodiment of the present invention.

[Explanation of symbols]

1 cylinder block, 1a cylinder bore, 1c suction communication passage, 2 front housing, 3 crank chamber,
Reference Signs List 4 rear housing, 4a partition, 5 valve plate, 8 suction chamber, 9 discharge chamber, 10 rotating shaft, 13 rotating support, 16 rotating swash plate, 17 swinging swash plate, 21 piston, 25 valve accommodating chamber, 26 rotary valve , 2
8 suction passage, 29 suction guide groove, 30 working chamber, 3
The leading end face and the trailing end face of the suction guide groove 29 located on the leading and trailing sides in the rotation direction of the rotary valves 1, 32, 3
3,34 Notch passage, K drive mechanism.

Claims (1)

(57) [Claims] 1. A cylinder block in which a plurality of cylinder bores for accommodating a piston are formed in parallel with each other, a plurality of housings joined to the cylinder block to form a suction chamber, a discharge chamber, and a drive chamber; A piston configured to compress gas sucked from a suction chamber and discharge the compressed gas to a discharge chamber by reciprocating the piston in a cylinder bore through a drive mechanism by rotation of a rotation shaft supported by a chamber-side housing. In the type compressor, a valve accommodating chamber that communicates with the suction chamber is provided for a housing and / or a cylinder block that forms the intake chamber, and the valve accommodating chamber and each of the cylinder bores communicate with each other through an intake communication passage, The valve chamber accommodates a rotary valve that is rotated in synchronization with the reciprocating motion of the piston. In the outer periphery of the rotary valve, a suction guide groove communicating with a suction communication passage communicating with a working chamber in a cylinder bore during a suction stroke is formed in a circumferential direction, and the suction chamber and the suction guide groove are formed inside a rotary valve. A suction passage which is always communicated with the gas suction guide groove and which is located on the leading side in the rotary valve rotation direction of the gas suction guide groove with a predetermined angle delay from the time when the compressed gas remaining in the top clearance in the cylinder bore ends re-expansion. The timing is adjusted so that the end face corresponds to the gas suction communication passage, and the residual compressed gas is re-applied to the outer peripheral surface of the rotary valve near the leading end face of the gas suction guide groove or the valve housing chamber near the suction communication passage. A piston type compressor provided with a notched passage that allows a small amount of gas to flow in and out from the end of expansion until the preceding end face corresponds to the suction communication passage. Refrigerant gas suction guide mechanism in the vehicle.