JP2002155856A - Reciprocating refrigerant compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reciprocating refrigerant compressor giving small pulsation without using a muffler. SOLUTION: This reciprocating refrigerant compressor comprises a shaft 5 to rotate by a driving force of a power source, a cylinder block 1 having at least four cylinder bores 6-1-6-7 formed along a circumferential direction of the shaft 5, and a piston 7 to reciprocate inside the cylinder bores 6-1-6-7 by the driving force transmitted to the shaft 5. All the cylinder bores 6-1-6-7 have different pitches.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a reciprocating refrigerant compressor, of a preferred reciprocating refrigerant compressor, especially CO ₂ as a refrigerant compressor of a vehicle air conditioner used as a refrigerant.

[0002]

2. Description of the Related Art A reciprocating refrigerant compressor has a cylinder block having a cylinder bore, a piston reciprocating linearly in the cylinder bore, a compression chamber formed in the cylinder bore, and a discharge from which refrigerant gas flows from the compression chamber. A cylinder head in which a chamber is formed, and a valve plate in which a discharge port for guiding refrigerant gas in the compression chamber to the discharge chamber is formed.
And a discharge valve for opening and closing the discharge port.

A valve plate, a discharge valve, and a cylinder head are fixed on one end surface of a cylinder block so as to be sequentially stacked.

[0004] When the piston moves from the bottom dead center position to the top dead center position, the refrigerant gas in the compression chamber is compressed. When a certain pressure difference occurs between the compression chamber and the discharge chamber, the discharge valve opens, and the refrigerant gas in the compression chamber flows out to the discharge chamber through the discharge port.

[0005]

By the way, in a refrigeration cycle using CO ₂ as a refrigerant, unlike a conventional refrigeration cycle using chlorofluorocarbon, refrigerant is not condensed in a high-pressure side heat exchanger. The generated pressure pulsation component is not easily attenuated. In addition, the pressure pulsation, particularly high pressure, is caused by a large pressure wave increase due to overcompression in each cylinder of the compressor (the refrigerant gas is compressed in the compression chamber more than the pressure required to open the discharge valve). Large pulsation. This high-pressure pulsation propagates from the high-pressure side heat exchanger to the vehicle body through the mounting bracket and becomes noise, and this noise enters the vehicle interior.

As a countermeasure against the pulsation, it is possible to attach a muffler to the refrigerant compressor to attenuate the high-pressure pulsation. However, in this case, there is a problem that the cost becomes extremely high.

[0007] The present invention has been made in view of such circumstances, and an object thereof is to provide a reciprocating refrigerant compressor that can suppress pulsation without using a muffler.

[0008]

According to a first aspect of the present invention, there is provided a reciprocating refrigerant compressor comprising: a shaft rotated by a driving force of a driving source; In a reciprocating refrigerant compressor including a cylinder block in which at least four cylinder bores are formed, and a piston that reciprocates in the cylinder bore by a driving force transmitted to the shaft, the cylinder bores are arranged at unequal pitch. It is characterized by being.

As described above, since the cylinder bores are arranged at unequal pitch, the discharge intervals are not uniform, and the discharge pressure peaks hardly overlap. As a result, pulsation 1
The energy of the next component can be dispersed, and pulsation can be reduced.

"The discharge pressure peaks overlap" means the following state. As shown in FIGS. 3 to 5 described later, the pressure change in the discharge chamber when the shaft makes one rotation at a constant rotation speed is graphed (in FIGS. 3 to 5, the vertical axis represents the pressure in the discharge chamber, and the horizontal axis represents the shaft of the shaft. Rotation angle is shown), and the waveform of one discharge pressure peak (the discharge pressure peak and its vicinity) is plotted along the horizontal axis of the graph (the axis showing the rotation angle of the shaft) at equal pitches of cylinder bores (360). (° / number of cylinders) means that the waveform of one discharge pressure peak portion substantially overlaps the waveform of another discharge pressure peak portion. The movement range of the discharge pressure peak portion at this time is within 360 ° with respect to the position.

According to a second aspect of the present invention, there is provided a reciprocating type refrigerant compressor, comprising: a shaft which is rotated by a driving force of a driving source; a cylinder block having at least four cylinder bores formed along a circumferential direction of the shaft; A piston that reciprocates in the cylinder bore by a driving force transmitted to a shaft;
The pitches of the cylinder bores are all different.

As described above, since the pitches of the cylinder bores are all different, the discharge intervals are all different, and the discharge pressure peaks do not overlap. As a result, the energy of the primary component of the pulsation can be dispersed, and the pulsation can be reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a variable displacement swash plate type compressor according to an embodiment of the present invention, and FIG. 2 is a view showing a rear end surface of a cylinder cylinder block of the swash plate type compressor shown in FIG. .

This variable capacity swash plate type compressor is used as one component of a refrigeration cycle using CO ₂ (carbon dioxide) as a refrigerant. A rear head (cylinder head) 3 is disposed on one end surface of a cylinder block 1 of the compressor via a valve plate 2, and a front head 4 is disposed on the other end surface. The front head 4, the cylinder block 1, the valve plate 2, and the rear head 3 are integrally connected in the axial direction with a through bolt 31 and a nut 32.

The front head 4 has a crank chamber 8 for accommodating a thrust flange 40, a swash plate 10, and the like.

The thrust flange 40 is fixed to the shaft 5 and rotates integrally with the shaft 5.

The thrust flange 40 is rotatably supported on the inner peripheral surface 4a of the front head 4 via a thrust bearing 33. The swash plate 10 is mounted so as to be slidable with respect to the shaft 5 and tiltable with respect to an imaginary plane perpendicular to the shaft 5.

The swash plate 10 is connected to a thrust flange 40 via a link mechanism 41, and rotates together with the rotation of the thrust flange 40. Both sliding surfaces 10 of the swash plate 10
Hemispherical shoes 60, 61 are arranged on the swash plate 10 so as to sandwich the swash plate 10, and can relatively rotate on the sliding surfaces 10 a, 10 b of the swash plate 10 as the shaft 5 rotates.

The cylinder block 1 includes a shaft 5
Are formed along the circumference centered at. As shown in FIG.
6-7 are arranged at irregular pitches along the circumferential direction of the shaft 5, and the values of the angles α1 to α7 between the cylinder bores 6-1 to 6-7 (the angles between the cylinder bores) are all different. I have. In the case of the present embodiment, α1 is 54.43.
°, α2 is 48.43 °, α3 is 60.43 °, α4 is 42.43 °, α5 is 57.43 °, and α6 is 45.43.
° and α7 are 51.43 °. Here, as shown in FIG. 2, when there are seven line segments L1 to L7 connecting the center of the shaft 5 and the center of the cylinder bore 6, the “angle between cylinder bores” is formed by adjacent line segments L1 to L7. Angle. A piston 7 is slidably housed in each of the seven cylinder bores 6.

The piston 7 has a cylindrical portion 72 and a concave portion 7.
1, 70 and a bridge portion 7 connecting the concave portions 71, 70
And 3. The cylindrical portion 72 slides in the cylinder bore 6.

The concave portion 71 is formed at one end of the cylindrical portion 72 and holds the shoe 61 so as to roll.

The concave portion 70 and the concave portion 71 are opposed to each other and hold the shoe 60 so as to be rollable.

The rear head 3 has a suction chamber 13 and a discharge chamber 12 formed therein.

The suction chamber 13 is located around the discharge chamber 12. The suction chamber 13 contains a low-pressure refrigerant gas to be supplied to the compression chamber 22. The discharge chamber 12 contains the high-pressure refrigerant gas discharged from the compression chamber 22.

An insertion hole 81 for the bolt 19 is formed in the center of the valve plate 2. The valve plate 2 has a discharge port 16 for communicating the compression chamber 22 with the discharge chamber 12 and a suction port 15 for communicating the compression chamber 22 with the suction chamber 13 along the circumferential direction of the shaft 5. It is provided at intervals. The suction port 15 and the discharge port 16 are each provided with an opening edge 6 of the cylinder bore 6.
a, the suction port 15 is located outside the discharge port 16 (radially outside the valve plate 2).
The suction port 15 is opened and closed by a suction valve 21 and the suction valve 2
Reference numeral 1 denotes a front end face of the valve plate 2. The discharge port 16 is opened and closed by a discharge valve 17. The discharge valve 17 is fixed to a rear head side end surface 2 a of the valve plate 2 by a bolt 19 together with a valve retainer 18.

The numbers of the opening / closing portions 21a of the suction valve 21, the opening / closing portions 17a of the discharge valve 17, the suction port 15, the discharge port 16 and the compression chambers 22 are each equal to the number of the cylinder bores 6 (7 in this embodiment).

One end of the shaft 5 is rotatably supported by the front head 4 via a radial bearing 26, and the other end of the shaft 5 is a radial bearing 25 and a thrust bearing 24.
And is rotatably supported by the cylinder block 1 via the.

A communication passage (not shown) is provided between the suction chamber 13 and the crank chamber 8, and an orifice (not shown) is provided in the middle of the communication passage. The discharge chamber 12
A communication passage (not shown) is provided between the motor and the crank chamber 8, and a pressure adjusting valve (not shown) is provided in the middle of the communication passage, and the pressure in the crank chamber 8 is adjusted by the pressure adjusting valve. The communication passage is opened and closed.

A winding spring 47 is mounted between the thrust flange 40 and the swash plate 10, and the swash plate 10 is urged rearward by the urging force of the winding spring 47. A winding spring 48 is mounted between the swash plate 10 and the thrust bearing 24, and the swash plate 10 is urged toward the front side by the urging force of the winding spring 48.

Next, the operation of the variable displacement type swash plate type compressor will be described.

When the rotational driving force of the vehicle engine (not shown) is transmitted to the shaft 5, the rotational force of the shaft 5 is transmitted to the swash plate 10 through the thrust flange 40, and the swash plate 10 rotates. Due to the rotation of the swash plate 10, the shoes 60 and 61 relatively rotate on the sliding surfaces 10a and 10b of the swash plate 10,
The rotational force from zero is converted into a linear reciprocating motion of the piston 7.

When the piston 7 reciprocates in the cylinder bore 6, the volume of the compression chamber 22 in the cylinder bore 6 changes, and the suction, compression and discharge of the refrigerant gas are sequentially performed by this volume change, and the inclination angle of the swash plate 10 is changed. The high-pressure refrigerant gas having a capacity corresponding to the pressure is discharged. At the time of suction, the suction valve 21 is opened, low-pressure refrigerant is sucked from the suction chamber 13 into the compression chamber 22 in the cylinder bore 6, and at the time of discharge, the discharge valve 17 is opened, and high-pressure refrigerant gas flows from the compression chamber 22 to the discharge chamber 12. Discharged.
The high-pressure refrigerant gas in the discharge chamber 12 is discharged from the discharge port 3a to a cooler (not shown).

In the suction stroke, as the piston 7 moves to the bottom dead center side, a large pressure difference is generated between the compression chamber 22 and the suction chamber 13, and the suction valve 21 is bent toward the compression chamber 22 and the suction port 15 is closed. open.

In the compression stroke, as the piston 7 moves to the top dead center, the volume of the compression chamber 22 gradually decreases,
The pressure in the compression chamber 22 increases.

In the discharge stroke, the volume of the compression chamber 22 is minimized, and the pressure in the compression chamber 22 is maximized. When a certain pressure difference occurs between the compression chamber 22 and the discharge chamber 12, the discharge valve 17 bends toward the discharge chamber 12, and the discharge port 16 is opened.

When the heat load decreases and the pressure regulating valve opens to increase the pressure in the crank chamber 8, the inclination angle of the swash plate 10 decreases, so that the stroke amount of the piston 7 decreases and the discharge capacity decreases. . On the other hand, when the heat load increases and the pressure regulating valve closes and the pressure in the crank chamber 8 decreases, the inclination angle of the swash plate 10 increases, so that the stroke amount of the piston 7 increases and the displacement increases. .

Next, regarding the operation and effect of this embodiment,
A description will be given in comparison with two comparative examples.

Table 1 below shows the angle between cylinder bores in Comparative Example 1, the difference between the angle between cylinder bores and the same pitch in this embodiment, and the difference between the angle between cylinder bores and the same pitch in Comparative Example 2. Here, the “difference from equal pitch” means the angle between cylinder blocks and the equal pitch (3
60 ° / number of cylinders). When the value of “difference from equal pitch” is plus, it indicates that the angle between cylinder bores is larger than equal pitch, and when the value of “difference from equal pitch” is minus, the angle between cylinder bores is smaller than equal pitch. It is shown that.

[0040]

[Table 1] As is clear from Table 1, Comparative Example 1 is a seven-cylinder compressor in which the cylinder bores are arranged at equal pitches along the circumferential direction of the shaft. Comparative Example 2 is also a 7-cylinder compressor, but the cylinder bores are arranged at irregular pitches along the circumferential direction of the shaft. However, in the case of Comparative Example 2, there are three values of “difference from equal pitch”, and therefore, the discharge pressure peaks overlap in two ways, each of which occurs twice.

FIG. 3 is a graph showing a pressure change in the discharge chamber when the shaft makes one rotation at a constant rotation speed in Comparative Example 1. FIG. 4 shows a graph when the shaft makes one rotation at a constant rotation speed in this embodiment. 5 is a graph showing a pressure change in the discharge chamber, and FIG. 5 is a graph showing a pressure change in the discharge chamber when the shaft makes one rotation at a constant rotation speed in Comparative Example 2.

In the case of Comparative Example 1 in which the pitches of the cylinder bores are equal, the change in the discharge pressure is constant as is apparent from FIG. On the other hand, in the case of the present embodiment and Comparative Example 2 in which the pitches of the cylinder bores are not equal, as is clear from FIGS. 4 and 5, the change in the discharge pressure is not constant. FIG.
As is clear from the comparison between FIG. 5 and FIG. 5, in the present embodiment, the time intervals between the pressure peaks are all different, but in Comparative Example 2, the time intervals between the pressure peaks partially match.

For each of the compressors of this embodiment, Comparative Example 1, and Comparative Example 2, 360 ° / 7 (number of cylinders) ≒ 51.43.
FIG. 6 shows the overlap of the discharge pressure changes due to the periodicity from each cylinder bore in the range of °.

As is clear from FIG. 6, in the case of the present embodiment, there is clearly no overlap of the discharge peaks, the discharge pressure is averaged, and the pulsation is small as compared with Comparative Examples 1 and 2.

FIG. 7 is a graph showing a pressure change in one cylinder bore, a pressure change in the discharge chamber, and a pressure change in the suction chamber when the shaft makes one rotation at a constant rotation speed in this embodiment.

In the above embodiment, the values of the pitch angles α1 to α7 of the cylinder bores 6-1 to 6-7 are all different so that the discharge timings do not completely overlap. The ejection timings may overlap by about one time during the operation.

The “difference from the uniform pitch” needs to be at least 2 ° in order to avoid overlapping of the discharge pressure peaks, and the maximum value of the “difference from the uniform pitch” is the pressure within each cylinder bore. It is generally within 11 ° within a range in which the thickness between cylinders that can withstand the change can be secured and a piston or the like can be stored.

In the above-described embodiment, the variable capacity type swash plate type refrigerant compressor has been described as an example of the reciprocating type refrigerant compressor. The present invention can be applied.

[0049]

As described above, according to the reciprocating refrigerant compressor of the first aspect of the invention, pulsation can be reduced without using a muffler.

According to the second aspect of the present invention, the pulsation can be further reduced without using a muffler.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a variable displacement swash plate type compressor according to an embodiment of the present invention.

FIG. 2 is a plan view of a cylinder cylinder block of the swash plate type compressor shown in FIG. 1 as viewed from a valve plate.

FIG. 3 is a graph showing a pressure change in a discharge chamber when a shaft makes one rotation at a constant rotation speed in Comparative Example 1.

FIG. 4 is a graph showing a pressure change in the discharge chamber when the shaft makes one rotation at a constant rotation speed in this embodiment.

FIG. 5 is a graph showing a pressure change in a discharge chamber when the shaft makes one rotation at a constant rotation speed in Comparative Example 2.

FIG. 6 is a diagram showing the average of the discharge pressure from each cylinder bore in the range of 360 ° / 7 (the number of cylinders) for each compressor of the present embodiment, Comparative Example 1, and Comparative Example 2.

FIG. 7 is a graph showing a pressure change in one cylinder bore, a pressure change in a discharge chamber, and a pressure change in a suction chamber when the shaft makes one rotation at a constant rotation speed in the present embodiment.

[Explanation of symbols]

 1 Cylinder block 5 Shaft 6-1 to 6-7 Cylinder bore 7 Piston

Claims (2)

[Claims] A shaft rotated by a driving force of a driving source; a cylinder block having at least four cylinder bores formed in a circumferential direction of the shaft; A reciprocating refrigerant compressor including a reciprocating piston, wherein the cylinder bores are arranged at unequal pitch. 2. A shaft which is rotated by a driving force of a driving source, a cylinder block in which at least four cylinder bores are formed along a circumferential direction of the shaft, and the inside of the cylinder bore is driven by the driving force transmitted to the shaft. A reciprocating refrigerant compressor including a reciprocating piston, wherein pitches of the cylinder bores are all different.