JPH07279842A - Refrigerant gas suction structure in reciprocating type compressor - Google Patents

Abstract

PURPOSE:To lighten drive force load due to suction pressure loss by sucking refrigerant gas in a suction process. CONSTITUTION:A plurality of cylinder bores 20 are drilled on a cylinder block 1 such that a drive shaft is surrounded and double faced pistons 22 are stored in the respective bores. A rotary valve is stored in a storing hole such that it can synchronously turn with the drive shaft and a suction passage is formed in the rotary valve. A conductive passage 45 having an open surface 45a formed with an upper dead point side end part 45d longer than a width of a lower dead point side end part 45b is arranged in a position a little away from the upper dead point between the cylinder bore 20 and the storing hole. Smooth suction motion of refrigerant gas can be provided by providing an initial open area of the conductive passage 45 for opening by backward movement of the double faced piston 22 in a suction process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant in a reciprocating compressor which accommodates pistons in a plurality of cylinder bores arranged around a drive shaft and reciprocates the pistons in association with the rotation of the drive shaft. The present invention relates to a gas suction structure.

[0002]

2. Description of the Related Art Conventionally, each piston reciprocates in a plurality of cylinder bores formed in a cylinder block in parallel with a drive shaft, such as a swash plate compressor disclosed in Japanese Patent Laid-Open No. 5-71467. A reciprocating compressor that compresses a refrigerant gas is known. In this type of compressor, the drive shaft is inserted and supported in the central shaft hole of the cylinder block,
Each piston is linked to the swash plate in the crank chamber that cooperates with this drive shaft, and moves linearly in each cylinder bore. A housing is joined to the end surface of the cylinder block via a valve plate, and a discharge chamber for discharging the refrigerant gas compressed by the piston in the cylinder bore is formed in the housing. Further, between the cylinder bores and the central shaft hole in the cylinder block, there is formed a conduction path that radially connects the cylinder bores and the central shaft hole. Since the conduction path is formed by joining the valve plate to the groove formed on the end surface of the cylinder block, it is provided so as to open near the top dead center of the piston moving in the cylinder bore. A rotary valve that rotates in synchronization with the rotation of the drive shaft is connected to the drive shaft. The rotary valve is provided with an intake passage that sequentially connects the communication passage connected to the cylinder bore during the intake stroke and the intake chamber in the central shaft hole. Then, by rotating the rotary valve in synchronization with the drive shaft, the refrigerant gas in the suction chamber is sequentially sucked into each cylinder bore through the suction passage and the communication passage while the piston is in the suction stroke. The discharge of the refrigerant gas from the inside of the cylinder bore to the discharge chamber is performed by moving the piston to the top dead center position, and the discharge port formed in the valve plate and the discharge port side of the discharge port are provided in the cylinder bore. And a discharge valve that opens the discharge port in response to pressure.

[0003]

However, in this conventional compressor, since the communication passage opens near the top dead center in the cylinder bore, the gas near the end of the compression stroke of the piston, that is, the higher pressure gas Are confined in the conduction path, and the amount of residual gas increases. Such residual gas re-expands as the piston retreats to the bottom dead center position, which leads to a decrease in the amount of refrigerant gas sucked from the suction chamber into the cylinder bore, deteriorating the volumetric efficiency.

Therefore, it is conceivable to reduce the residual gas by opening the conducting path in the cylinder bore at a position slightly displaced from the top dead center side to the bottom dead center side. In this case, since the communication passage is formed in the cylinder block, it is necessary to form a hole communicating with the suction passage of the rotary valve. Then, in order to facilitate the processing, the hole of the conduction path is formed by a drill or the like, and its cross section and the opening surface are formed in a circular shape. In this way, when the opening surface of the conduction path is circular, the opening area of the conduction path gradually increases as the piston moves back to the bottom dead center position.

Therefore, as shown by a solid line (area surrounded by a dotted line and a solid line) in FIG. 7, a remarkable suction pressure loss can be confirmed in the section A where the opening area changes. It is considered that this is because the opening area in the initial stage of the suction stroke is narrow, so that a restriction occurs in the conduction path. Therefore, a large driving force is required for the piston in the suction stroke due to the driving resistance generated by the throttle, which is considered to cause the power loss of the compressor. As a solution to this problem, it is conceivable to increase the opening area of the opening surface on the cylinder bore side. However, simply increasing the opening area of the conducting path leads to an increase in dead volume in the cylinder block. This increase in dead volume leads to an increase in the above-mentioned residual gas amount, which leads to a decrease in the refrigerant gas suction amount from the suction chamber into the cylinder bore, thus deteriorating the volumetric efficiency. There is.

The present invention has been made to solve the above problems, and its purpose is to achieve quick and stable refrigerant gas suction in the suction stroke, thereby reducing the load of driving force due to suction pressure loss. It is an object of the present invention to provide a refrigerant gas suction structure for a reciprocating compressor.

[0007]

In order to solve the above problems, the invention according to claim 1 accommodates a piston in a plurality of cylinder bores arranged so as to surround a drive shaft with respect to a cylinder block, and By reciprocating the piston in conjunction with the rotation of the drive shaft, the refrigerant gas is sucked from the suction passage into the compression chamber defined in the cylinder bore, and the compressed refrigerant gas is discharged into the discharge chamber. In the reciprocating compressor described above, a housing hole provided in the cylinder block and located coaxially with the drive shaft is slidably fitted into the housing hole, and is supported so as to be rotatable synchronously with the drive shaft. At the same time, the rotary valve in which the suction passage for sucking the refrigerant gas from the suction passage to the compression chamber during the suction stroke is formed, and the accommodation hole and the compression chamber are communicated with each other, The piston is arranged at a position to be closed by the outer peripheral surface of the piston before reaching the top dead center, and the width of the top dead center side end portion in the direction orthogonal to the axial direction is equal to or larger than the bottom dead center side width. It is a gist of the present invention to provide a conducting path having an opening surface formed in the.

According to a second aspect of the present invention, in the invention according to the first aspect, the width of the opening surface is formed so that the bottom dead center side is shorter than the top dead center side. To do.

[0009]

According to the present invention, the above configuration is adopted.
In the invention described in (1), the outlet of the suction passage formed in the rotary valve is sequentially communicated with the plurality of conductive passages as the rotary valve rotates. Therefore, the suction passage and the compression chamber are sequentially communicated with each other through the suction passage and the conduction passage. This communication is performed in synchronization with the suction operation of the piston with respect to each compression chamber. When the suction passage and the compression chamber are in communication with each other, the piston moves toward the bottom dead center side, and the pressure in the compression chamber decreases to the pressure in the suction passage (suction pressure) or less. Due to this pressure decrease, the refrigerant gas in the suction passage flows into the compression chamber through the suction passage and the communication passage.

In the suction stroke in which the piston moves from the top dead center side to the bottom dead center side, the opening area on the compression chamber side of the communication passage communicating with the suction passage increases as the piston moves backward. In the initial stage where the opening area increases, the opening surface on the compression chamber side of the conduction path is in a sufficiently opened state. Therefore, the refrigerant gas in the communication passage is hardly subjected to throttling, and is smoothly flowed into the compression chamber due to the suction negative pressure caused by the retreat of the piston.

During the discharge operation of the refrigerant gas, the communication between the suction passage and the compression chamber during the compression stroke is blocked by the outer peripheral surface of the rotary valve. Therefore, the gas sucked into the compression chamber is compressed, and the pressure rises as the piston moves. Then, before the piston reaches the top dead center where the pressure of the compressed gas becomes maximum, the opening surface on the compression chamber side of the communication path that connects the suction passage and the compression chamber is closed by the outer peripheral surface of the piston. Then, the refrigerant gas in the compression chamber is discharged to the discharge chamber when the pressure reaches or exceeds the set pressure.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment embodying the present invention will now be described with reference to FIGS.
A description will be given based on FIG. As shown in FIG. 2, accommodating holes 1a and 2a are provided at the center of the pair of joined front and rear cylinder blocks 1 and 2. A front housing 3 and a rear housing 4 are joined to the end surfaces of the cylinder blocks 1 and 2 via valve plates 5 and 6. Support holes 5a and 6a are formed through the valve plates 5 and 6, respectively. Annular positioning projections 5b and 6b are provided on the peripheral edges of the support holes 5a and 6a so as to project toward the cylinder blocks 1 and 2 side.
a and 2a. Cylinder block 1, 2,
Pins 7 and 8 are inserted through the valve plates 5 and 6 and both housings 3 and 4, and rotation of the valve plates 5 and 6 and both housings 3 and 4 relative to the cylinder blocks 1 and 2 is blocked by the pins 7 and 8. Has been done. The cylinder block 1, the valve plate 5 and the front housing 3 are fixed by bolts 9, and the cylinder block 2, the valve plate 6 and the rear housing 4 are fixed by bolts 10.

Support holes 5a, 6a for the valve plates 5, 6
A drive shaft 11 is rotatably supported by conical roller bearings 12 and 13. Radial load and thrust load on the drive shaft 11 are received by the conical roller bearings 12 and 13. A preload applying spring 14 is interposed between the front housing 3 and the conical roller bearing 12. A preload in the thrust direction is applied to the drive shaft 11 through the conical roller bearing 12 by the bending deformation of the preload applying spring 14 due to the tightening force of the bolt 9. Seal rings 15 and 16 are interposed between the valve plates 5 and 6 and the drive shaft 11. A swash plate 17 is fixedly supported on the drive shaft 11. The cylinder blocks 1 and 2 forming the swash plate chamber 18 as the suction passage are formed with an inlet port 19, and the inlet port 19 is connected to an external suction refrigerant gas pipe line (not shown).

As shown in FIGS. 3 and 4, a plurality of cylinder bores 20 are provided at equidistant angular positions about the drive shaft 11.
21 is formed. As shown in FIG. 2, a double-headed piston 22 is reciprocally housed in each pair of front and rear cylinder bores 20 and 21 (five pairs in this embodiment). Hemispherical shoes 23 and 24 are interposed between the double-headed piston 22 and both front and rear surfaces of the swash plate 17. Therefore, the swash plate 17
Is converted into a reciprocating motion of the double-headed piston 22 in the cylinder bores 20, 21 via the shoes 23, 24.

On the other hand, the discharge chamber 2 is provided in both housings 3 and 4.
5, 26 are formed. Compression chambers Pa and Pb defined by the double-headed piston 22 in the cylinder bores 20 and 21.
Is connected to the discharge chambers 25, 26 via the discharge ports 5c, 6c on the valve plates 5, 6. Discharge port 5
C and 6c are opened and closed by flapper valve type discharge valves 27 and 28. The opening degrees of the discharge valves 27 and 28 are the retainers 29 and 30.
Regulated by Discharge valves 27, 28 and retainer 2
9 and 30 are valve plates 5 by bolts (not shown)
6 is fastened and fixed on top. The discharge chamber 25 has a discharge passage 31
Through an external discharge refrigerant gas pipe (not shown).

One end of the drive shaft 11 has a front housing 3
To the outside, and the other end projects into the discharge chamber 26 on the rear housing 4 side. A discharge passage 32 is formed at the axial center of the drive shaft 11. The discharge passage 32 opens into the discharge chamber 26. A lead-out port 33 is formed in a peripheral surface portion of the drive shaft 11 which is surrounded by the discharge chamber 25 on the front housing 3 side, and the discharge chamber 25 and the discharge passage 32 are connected by the lead-out port 33. Therefore, the front and rear discharge chambers 25 and 26 are communicated with each other by the discharge passage 32, and the refrigerant gas in the discharge chamber 26 flows into the discharge chamber 25 from the discharge passage 32.

The periphery of the swash plate chamber 18 is a suction pressure region, and the discharge chambers 25 and 26 are discharge pressure regions. Therefore, the refrigerant gas discharged from the discharge chambers 25 and 26 tends to leak to the accommodation holes 1a and 2a, but this leakage is prevented by the seal rings 15 and 16.

Reference numeral 34 denotes the discharge chamber 2 along the peripheral surface of the drive shaft 11.
5 is a lip seal for preventing refrigerant gas from leaking from the compressor 5 to the outside of the compressor. On the drive shaft 11, rotary valves 35 and 36 having a tapered shape are fitted and supported by the drive shaft 11. Key grooves 35d and 36 that engage with keys 37 and 38 fixed to the drive shaft 11 are provided on the rotary valves 35 and 36.
d is provided. The rotary valves 35 and 36 are housed in the housing holes 1a and 2a so as to be integrally rotatable with the drive shaft 11 in the direction of arrow Q in FIGS. 3 and 4, and slidably in the axial direction.

The accommodating holes 1a, 2a have a taper shape, and each of them has a diameter increasing toward the swash plate chamber 18 side. The rotary valves 35 and 36 are fitted and inserted so that their peripheral surfaces 35a and 36a are brought into contact with the inner peripheral surfaces of the accommodation holes 1a and 2a. That is, the small diameter end 35b of the rotary valve 35 faces the discharge chamber 25 side, and the large diameter end 35c of the rotary valve 35 faces the swash plate chamber 18 side. The small diameter end 36b of the rotary valve 36 faces the discharge chamber 26 side, and the large diameter end 36c of the rotary valve 36 faces the swash plate chamber 18 side.

Large diameter ends 35 of the rotary valves 35, 36
c and 36c are recesses 35e and 3 which open to the swash plate chamber 18.
6e is formed, and the bottom walls of the recesses 35e and 36e and the swash plate 1 are formed.
Sealing force imparting springs 39 and 40 are interposed between the springs 7 and 7. The sealing force imparting springs 39, 40 urge the rotary valves 35, 36 from the large diameter end portions 35c, 36c side to the small diameter end portions 35b, 36b side. Therefore, the peripheral surfaces 35a and 36a are sealed with the sealing force imparting springs 39 and 40.
Due to the spring force, the inner peripheral surfaces of the accommodation holes 1a, 2a come into close contact with each other.

Suction passages 41 and 42 are formed in the rotary valves 35 and 36. The inlets 41a, 42a of the suction passages 41, 42 are open toward the recesses 35e, 36e, and the outlets 41b, 42b of the suction passages 41, 42 are opened on the peripheral surfaces 35a, 36a of the rotary valves 35, 36. There is. The peripheral surfaces 35a of the rotary valves 35, 36,
Guide grooves 43, 44 connected to the suction passages 41, 42 are provided on the 36a along the circumferential direction.

As shown in FIG. 3, on the inner peripheral surface of the accommodating hole 1a for accommodating the rotary valve 35, the same number of conducting passages 45 as the cylinder bores 20 are arrayed at equidistant angular positions. The conducting passages 45 and the cylinder bores 20 are always in one-to-one communication with each other, and each conducting passage 45 is connected to the inside of the circulation region of the outlet 41b of the suction passage 41.

Similarly, as shown in FIG. 4, on the inner peripheral surface of the accommodation hole 2a for accommodating the rotary valve 36, the same number of conduction passages 46 as the cylinder bores 21 are arrayed at equidistant angular positions. The communication passages 46 and the cylinder bores 21 are always in one-to-one communication with each other, and each of the conduction passages 46 is connected within the circulation region of the outlet 42b of the suction passage 42.

As shown in FIG. 1, an opening surface 45a of the conduction path 45 on the cylinder bore 20 side has a substantially T-shape, and the opening portion on the top dead center side with respect to the area of the opening portion 45b on the bottom dead center side. Four
5c is formed in a shape with a large area. The top dead center side opening 45c is formed in a substantially rectangular shape by a top dead center side end 45d, a bottom dead center side end 45e, and a side end 45f extending in the axial direction. Also, the opening 45b on the bottom dead center side
Is composed of a bottom dead center side end 45e, a bottom dead center side end 45g, and a side end 45h extending in the axial direction, and forms a continuous opening surface together with the opening 45c. The top dead center side end portion 45d of the opening surface 45a is set at a position separated from the top dead center by a predetermined distance L, and the top dead center side end portion 45d, the bottom dead center side end portion 45e, and the bottom dead center side end portion. 45 g is formed to be parallel to the end surface 22 a of the double-headed piston 22. The area of the opening surface 45a of the communication path 45 is set to a value that enables stable gas intake according to the amount of intake gas required in the cylinder bore 20. or,
Conducting paths 45, 46 for each cylinder bore 20, 21
Also has an opening surface of the same shape as described above.

Next, the operation of the refrigerant gas suction structure in the reciprocating compressor having the above construction will be described. Swash plate room 18
When the pressure in the compression chambers Pa, Pb becomes lower than the pressure in the swash plate chamber 18, the refrigerant gas supplied into the communication passages 45, 46 in communication with the suction passages 41, 42 and the guide grooves 43, 44.
Through the compression chambers Pa and Pb.

In the state shown in FIGS. 2, 3 and 4, the double-ended piston 22 is at the top dead center position with respect to one cylinder bore 20 and at the bottom dead center position with respect to the other cylinder bore 21. When the double-headed piston 22 enters the intake stroke toward the bottom dead center position from the top dead center position with respect to the cylinder bore 20, the intake passage 41 is provided with the compression chamber Pa of the cylinder bore 20.
Communicate with. By this communication, the refrigerant gas in the swash plate chamber 18 is sucked into the compression chamber Pa of the cylinder bore 20 via the suction passage 41, the guide groove 43, and the communication passage 45.

On the other hand, the double-headed piston 22 has the cylinder bore 2
When the compression stroke from the bottom dead center position to the top dead center position with respect to 1 is entered, the suction passage 42 and the guide groove 44 are cut off from communication with the compression chamber Pb of the cylinder bore 21. Due to this disconnection, the refrigerant gas in the compression chamber Pb of the cylinder bore 21 is compressed along with the movement of the double-headed piston 22, and when compressed to a predetermined pressure, the discharge valve 28 is pushed away and discharged from the discharge port 6c to the discharge chamber 26. .

Such suction and discharge of the refrigerant gas are similarly performed in the compression chambers Pa and Pb of the other cylinder bores 20 and 21. In the suction stroke, when the double-headed piston 22 retreats and the end surface 22a of the double-headed piston 22 reaches the opening 45a of the communication passages 45 and 46, the refrigerant gas passes through the wide opening 45c and the compression chamber Pa, P
It smoothly flows into b. At this time, as shown by the solid line in FIG. 5, the area of the initial opening surface is set to be sufficiently wider than that of the conduction path having the circular cross section shown by the two-dot chain line, so that each cylinder bore 20, In 21, the suction operation of the refrigerant gas is promptly and stably continued. As a result, it is possible to reduce the flow resistance, that is, the suction resistance in the refrigerant gas flow path from the swash plate chamber 18 to the compression chambers Pa and Pb, and it is possible to reduce the two-dot chain line (the area surrounded by the two-dot chain line in FIG. 7). As shown in (), the pressure loss in suction can be suppressed to a very small value.

As described above in detail, according to the refrigerant gas suction structure in the reciprocating compressor of this embodiment, the swash plate chamber 18
Since it is possible to reduce the suction resistance in the refrigerant gas flow path from the compression chambers Pa, Pb to the compression chambers Pa, Pb, the double-headed piston 22 can be driven smoothly. Therefore, since excessive resistance does not act on the driving force of the drive shaft, it is possible to reduce the loss of power consumed in the intake stroke. Further, since the area of the opening surface 45a of the conductive paths 45 and 46 is formed to be larger on the side of the top dead center than on the side of the bottom dead center, the area in the axial direction is larger than that of the circular opening surface having the same area. The length can be shortened. Therefore, the refrigerant gas required in the suction stroke can be sucked into the compression chambers Pa and Pb at an early stage.

The present invention is not limited to the above embodiments, but may be configured as follows, for example, without departing from the spirit of the invention. (1) In the above embodiment, the opening surface 4 of the conducting paths 45, 46.
Although 5a is formed in a substantially T shape, the present invention is not limited to this and may be, for example, conductive paths 45 and 46 having opening surfaces as shown in FIGS. 6 (a) and 6 (b). Further, the same effect can be obtained by forming the opening surface into a substantially square shape or a substantially rectangular shape. In the case of a substantially rectangular shape, it is preferable to form the short side in the axial direction, and the length of the short side is set to a predetermined length in consideration of the average flow rate of the suction gas due to the viscous resistance of the refrigerant gas.

(2) The cross-sectional shape of the conducting passages 45, 46 may be constant or may be changed midway from the opening surface on the suction passage 41, 42 side to the opening surface on the compression chamber Pa, Pb side. .

(3) In the above embodiments, the present invention is embodied in a swash plate type double-headed piston compressor. However, a swash plate type one-sided piston compressor, a variable displacement type swash plate type compressor, a swing swash plate type compressor, or a special type. It may be embodied in a wave plate type compressor or the like as disclosed in Kaihei 5-026158.

[0033]

As described in detail above, according to the first and second aspects of the present invention, the shape of the opening surface of the communication path on the compression chamber side does not increase the dead volume, and the opening of the piston at the initial stage of retreat is performed. Since the area is large, the refrigerant gas can be quickly and stably sucked in the suction stroke, and the driving force load due to the suction pressure loss can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part showing an opening surface of a conducting path of the present invention.

FIG. 2 is a cross-sectional view showing the entire compressor.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

FIG. 5 is a graph showing a relationship between an opening area of a conduction path and a drive shaft rotation angle.

FIG. 6 is a schematic perspective view showing a shape of an opening surface of a conduction path of a modified example.

FIG. 7 is a graph showing the relationship between the pressure in the compression chamber and the drive shaft rotation angle on the circular opening surface.

[Explanation of symbols]

1, 2 ... Cylinder block, 1a, 2a ... Housing hole, 11
... Drive shaft, 18 ... Swash plate chamber as intake passage, 20, 21 ...
Cylinder bore, 22 ... Double-headed piston, Pa, Pb ... Compression chamber, 25, 26 ... Discharge chamber, 35, 36 ... Rotary valve, 41, 42 ... Suction passage, 45, 46 ... Conducting passage, 45
a ... Open surface.

Claims (2)

[Claims] 1. A piston is housed in a plurality of cylinder bores arranged so as to surround a drive shaft with respect to a cylinder block, and the piston is reciprocated in association with the rotation of the drive shaft so that the piston is reciprocated. A reciprocating compressor configured to draw a refrigerant gas into a compression chamber defined in the cylinder bore and discharge the compressed refrigerant gas to a discharge chamber, the reciprocating compressor being provided in the cylinder block and coaxial with the drive shaft. An upper accommodation hole, which is slidably fitted into the accommodation hole, is supported so as to be rotatable in synchronization with the drive shaft, and sucks the refrigerant gas from the suction passage to the compression chamber during the suction stroke. A rotary valve having a suction passage formed therein, the housing hole and the compression chamber, and is closed by the outer peripheral surface of the piston before the piston reaches the top dead center. Reciprocating compressor, which is provided at a position where the end portion on the top dead center side is orthogonal to the axial direction and has a conduction path having an opening surface formed to be larger than the width on the bottom dead center side. Refrigerant gas suction structure in. 2. The width of the opening surface is formed so that the bottom dead center side is shorter than the top dead center side.
Refrigerant gas suction structure in the reciprocating compressor according to [4].