JP2000121191A - Stirling refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance refrigerating capacity while maintaining a cycle efficiency by making a dead capacity of a low temperature side heat exchanger smaller than that of a high temperature side heat exchanger in a refrigerator. SOLUTION: A high temperature side heat exchanger 20 and a regenerator 22 of the Stirling refrigerator are contained in four annular passages 19a. A low temperature side heat exchanger 21 is contained in a rear side passage RP1 of a rear head 5, and they are arranged in series. Positions of these exchangers or the like in a direction of a driving shaft 6 are offset at a predetermined size to the head 5 side with a slant plate 7 as a reference, and a dead capacity of the exchanger 21 is set to substantially zero. The plate 7 is integrally rotated with rotation of the shaft 6. A plurality of pistons P1 are sequentially linearly reciprocated at a phase difference of 90 degrees in cylinder bores B1. Thus, warm water in the exchanger 20 is circulated, and chilled water is circulated in the exchanger 21. Since the dead capacity of the exchanger 21 is zero, if total capacity of the dead capacities is constant, its refrigerating capability is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type Stirling refrigerator.

[0002]

2. Description of the Related Art A Stirling refrigerator uses natural gas (helium, nitrogen gas, etc.) as a refrigerant and is harmless to the environment. Its theoretical efficiency is higher than that of the CFC cycle and is equal to Carnot efficiency. Attention has been paid to various fields in view of the fact that it is easy to produce cryogenic temperatures, and it has been practically used, albeit slightly, as a cryogenic refrigerator.

[0003] There are various types of refrigerant compressors for automotive air conditioners. Among them, a swash plate compressor is easy to balance rotation, has small side pressure applied to a piston, and is excellent in vibration and reliability. .

As a Stirling engine utilizing the basic structure of the swash plate type compressor, a swash plate type Stirling engine described in Japanese Patent Application Laid-Open No. Hei 5-231240 is known.

In this swash plate type Stirling engine, a cylinder block is formed with four cylinder bores around an axis and parallel to the axis, and a swash plate chamber opening at the center of each cylinder bore is formed. Possible swashplates are accommodated. Four cylinder bores are arranged at regular intervals (90 °) in the circumferential direction.

A double-headed piston is reciprocally accommodated in each cylinder bore, and each piston is engaged with a swash plate via a pair of shoes. Each piston is driven with a phase difference of 90 °.

A front working space and a rear working space are formed before and after each piston. A high-temperature heat exchanger is arranged outside each front working space, and a low-temperature heat exchanger is arranged outside each rear working space.

A front working space of the cylinder bore and a rear working space of the cylinder bore adjacent to the cylinder bore communicate with each other through communication passages, and a regenerator is provided in each communication passage.

[0009]

In the case of this swash plate type Stirling engine, a heat exchanger is not provided in the working space, but the heat exchange is performed only on the cylinder wall surface of the water jacket covering the working space. Cycle efficiency is reduced due to shortage of the heat transfer area, and it is difficult to obtain high output.

[0010] The present invention has been made in view of such circumstances, and an object thereof is to provide a Stirling refrigerator capable of improving the refrigerating capacity while maintaining cycle efficiency.

[0011]

According to a first aspect of the present invention, there is provided a swash plate type Stirling refrigerator according to the present invention, wherein the dead volume of the low-temperature side heat exchanger is smaller than the dead volume of the high-temperature side heat exchanger. It is characterized by.

Here, an isothermal analysis model as a Stirling engine performance analysis method will be described. This analysis shows that heat regeneration is complete (regenerator efficiency 100%) The working gas in each space is uniform (isothermal) The instantaneous pressure in each space is the same The total mass of working gas is constant The working gas follows the state equation of perfect gas Engine rotation The speed was constant, and the steady-state periodic energy was assumed under the assumption that the potential energy and kinetic energy of the working gas were ignored.

From the above assumption, since the total mass M of the working gas is constant,

[0014]

(Equation 1) From the working gas state formula,

[0015]

(Equation 2) Substituting into equation (1) using the assumption that pressures P are the same,

[0016]

(Equation 3) Here, the regenerator temperature Tk is obtained as follows by assuming a linear temperature distribution in the regenerator.

[0017]

(Equation 4) In equation (3), the volumes Vc and V
e is fc as an arbitrary periodic function of the crank rotation angle θ.
(θ) and fe (θ), and let the dead volumes in each space of compression and expansion be Vdc and Vde,

[0018]

(Equation 5)

[0019]

(Equation 6) When working gas pressure P is obtained from equation (3),

[0020]

(Equation 7) The amount of heat radiation / heat reception Qc and Qh in the compression / expansion space is equal to the work Wc and Wh in both spaces, respectively, based on the assumption that the state change in both spaces is isothermal.

[0021]

(Equation 8)

[0022]

(Equation 9) From equations (8) and (9), the input power W of one cycle and the efficiency COPc of the cycle are

[0023]

(Equation 10)

[0024]

[Equation 11] Becomes

In the above equations, the symbols V, T,
P and M indicate volume, temperature, pressure, and mass, respectively.

The subscripts c, k, r, h, and e denote a compression space, a heat exchanger on the heat radiation side (high temperature side), a regenerator, a heat exchanger on the heat absorption side (low temperature side), and an expansion space, respectively.

FIG. 4 is a graph showing the result of performing a Stirling cycle calculation using an isothermal analysis model.

FIG. 4 shows the refrigeration capacity ratio when the pressure P, the volume V, and the temperature T are fixed and the dead volume ratio (dead volume of the low-temperature heat exchanger / dead volume of the high-temperature heat exchanger) is changed. The cycle efficiency (COPc) is shown.

In FIG. 4, the solid line indicates the refrigerating capacity (Q
c) Ratio and dotted line indicate cycle efficiency (COPc), respectively.

The refrigerating capacity when the dead volume ratio is 1 (the dead volume of the low-temperature side heat exchanger is equal to the dead volume of the high-temperature side heat exchanger) is shown as 1.

From the graph of FIG. 4, the smaller the dead volume ratio is,
That is, as the dead volume of the low-temperature side heat exchanger becomes smaller than the dead volume of the high-temperature side heat exchanger, the refrigerating capacity increases, and the cycle efficiency is constant regardless of the dead volume ratio.

According to the first aspect of the present invention, when the total sum of the dead volumes is constant while maintaining the cycle efficiency,
The refrigeration capacity can be improved compared to when the dead volume of the low-temperature side heat exchanger is equal to the dead volume of the high-temperature side heat exchanger.

The Stirling refrigerator according to the second aspect of the present invention
A cylinder body having a plurality of cylinder bores, two cylinder heads coupled to both end surfaces of the cylinder body, a plurality of pistons slidably housed in the cylinder bore, and a drive shaft integrated with the cylinder body; And a swash plate that linearly reciprocates the plurality of pistons in the cylinder bore with a predetermined phase difference, and a first swash plate formed on one of the pistons in the cylinder bore.
An operating space, a second operating space formed in the other of the pistons in the cylinder bore, a low-temperature side heat exchanger provided in the cylinder body and located near the first operating space, A high-temperature side heat exchanger provided in the cylinder body and located near the second working space; a regenerator disposed between the low-temperature side heat exchanger and the high-temperature side heat exchanger; A communication path for communicating the first working space of the cylinder bore with the second working space of the cylinder bore in which a piston driven with the predetermined phase difference with respect to the piston in the cylinder bore is accommodated. The dead volume of the low-temperature heat exchanger is smaller than the dead volume of the high-temperature heat exchanger.

When the total dead volume is constant while maintaining the cycle efficiency, the refrigerating capacity can be improved as compared with the case where the dead volume of the low-temperature side heat exchanger is equal to the dead volume of the high-temperature side heat exchanger. As well as the adoption of a swash plate structure, it is excellent in terms of vibration and reliability.

The Stirling refrigerator according to the third aspect of the present invention
3. The Stirling refrigerator according to claim 2, wherein the positions of the high-temperature side heat exchanger and the low-temperature side heat exchanger in the drive shaft direction are offset to a side where the drive shaft does not protrude with respect to the swash plate. The high-temperature side heat exchanger is located on the side where the drive shaft projects, and the low-temperature side heat exchanger is located on the side where the drive shaft does not project.

The space accommodating the high-temperature side heat exchanger can be reduced. In addition, the rear head is enlarged, so that the heat transfer area can be increased. Furthermore, there is no need to lengthen the drive shaft.

[0037]

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

FIG. 1 is a longitudinal sectional view showing a Stirling refrigerator according to one embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG.

The front-side cylinder block 3a and the rear-side cylinder block 3b are joined to face each other. The outer peripheral surfaces of both cylinder blocks 3a, 3b
Covered with.

The outer cylinder 13 and both cylinder blocks 3a, 3
A front head (cylinder head) 4 is fixed to the front end surface of the cylinder b, and a rear head (cylinder head) 5 is fixed to the rear end surfaces of the cylinder blocks 3a and 3b.

The size of the rear head 5 in the direction of the drive shaft 6 is larger than the size of the front head 4 in the direction of the drive shaft 6.

The cylinder block 2 is composed of the front cylinder block 3a, the rear cylinder block 3b, the front head 4 and the rear head 5.

Cylinder blocks 3a, 3 which are opposingly joined
A drive shaft 6 is disposed at the center of the drive shaft 6, and a swash plate 7 is fixed to the drive shaft 6, and the drive shaft 6 and the swash plate 7
It is rotatably supported by 9, 30, 31. The swash plate 7 is housed in a swash plate chamber 10.

The cylinder blocks 3a, 3 which are oppositely joined
b includes four cylinder bores B1, B2, B
Reference numerals 3 and B4 are arranged at equal intervals (90 ° intervals) on the same circumference centered on the drive shaft 6.

Each of the cylinder bores B1, B2, B3, B4 is parallel to the rotating shaft 6. In each of the cylinder bores B1 to B4, so-called double-headed pistons P1, P2, P3, P4
Are slidably accommodated.

The piston P1 has two cylindrical portions P1a and P1a.
1b and a bridge portion P1c that integrally connects these cylindrical portions P1a and P1b. Other piston P
2-3 have the same structure as the piston P1.

The cylindrical portion P1 of the piston P1 facing each other
Hemispherical grooves 16a, 16b into which spherical balls 15a, 15b made of high carbon steel are rollably fitted are formed on inner wall surfaces 17a, 17b of a, P1b.

The inner wall surfaces 17a, 1 of the cylindrical portions P1a, P1b
Part of the swash plate 7 enters a space formed by the inner wall surface 14 of the bridge portion 7b and the bridge portion P1c.

The balls 15a and 15b are rotatably supported on disks 30a and 30b which relatively rotate on the sliding surface of the swash plate 7.

The balls 15a, 15b and the disc 30a,
30b constitute shoes S1 and S2, and shoes S1 and S2
The rotational movement of the swash plate 7 is converted into linear reciprocating movements of the pistons P1 to P4 via S2.

In this embodiment, when the swash plate 7 rotates integrally with the rotary shaft 6, the pistons P1 to P4 reciprocate linearly in the cylinder bores B1 to B4 with a phase difference of 90 °.

Outer peripheral surfaces of the cylinder blocks 3a and 3b;
Outer cylinder 1 arranged outside cylinder blocks 3a, 3b
3, four passages (communication passages) 19a, 19b, 19c, and 19d penetrating in the axial direction are formed.

The high-temperature heat exchanger 20 and the regenerator 22 are accommodated in the passages 19a to 19d, and the low-temperature heat exchanger 21 is accommodated in the rear passages RP1 to RP4 of the rear head 5. The high-temperature side heat exchanger 20, the regenerator 22, and the low-temperature side heat exchanger 21 are arranged in series.

The positions of the high-temperature side heat exchanger 20, the regenerator 22 and the low-temperature side heat exchanger 21 in the direction of the drive shaft 6 are offset by a predetermined distance from the swash plate 7 toward the rear head 5 where the drive shaft 6 does not project. Have been.

The high-temperature side heat exchanger 20 is located on the side of the front head 4 from which the drive shaft 6 projects.

The low-temperature side heat exchanger 21 is located on the rear head 5 side where the drive shaft 6 does not protrude.

The dead volume of the low-temperature side heat exchanger 21 is almost zero.

Circulating water is circulated through the high-temperature side heat exchanger 20, and the circulating water is circulated between the circulating water and a heating device (not shown). Further, circulating water is also circulated through the low-temperature side heat exchanger 21, and the circulating water circulates with a cooling device (not shown).

FIG. 3 is a conceptual diagram for explaining a Stirling refrigerator according to one embodiment of the present invention.

As shown in FIG. 3, the working space FS of the cylinder bore B1 is connected to the high-temperature side heat exchanger 20 in the passage 19a through a front passage FP1 formed in the front head 4.
Is in communication with Low-temperature side heat exchanger 21 in passage 19a
Communicates with the working space RS of the cylinder bore B2 adjacent to the cylinder bore B1 via a rear passage RP2 formed in the rear head 5. That is, the cylinder bore B1
The working space FS of the cylinder bore B2 and the working space RS of the cylinder bore B2 adjacent to the cylinder bore B1 are connected to the front passage FP.
1, communicating through the passage 19a and the rear passage RP2,
One refrigeration cycle is configured.

The working space FS of the cylinder bore B2 communicates with the high-temperature heat exchanger 20 in the passage 19b via the front passage FP2 formed in the front head 4.
The low-temperature side heat exchanger 21 in the passage 19b is connected to a cylinder bore B2 through a rear passage RP3 formed in the rear head 5.
Is communicated with the working space RS of the cylinder bore B3 adjacent to. That is, the working space FS of the cylinder bore B2 and the working space RS of the cylinder bore B3 adjacent to the cylinder bore B2 communicate with each other via the front side passage FP2, the passage 19b, and the rear side passage RP3 to form one refrigeration cycle.

The working space FS of the cylinder bore B3 communicates with the high-temperature heat exchanger 20 in the passage 19c via the front passage FP3 formed in the front head 4.
The low-temperature side heat exchanger 21 in the passage 19c is connected to a cylinder bore B3 through a rear side through hole RP4 formed in the rear head 5.
Is communicated with the working space RS of the cylinder bore B4 adjacent to. That is, the working space FS of the cylinder bore B3 and the working space RS of the cylinder bore B4 adjacent to the cylinder bore B3 communicate with each other via the front side passage FP3, the passage 19c, and the rear side passage RP4 to form one refrigeration cycle. .

The working space FS of the cylinder bore B4 communicates with the high-temperature heat exchanger 20 in the passage 19d via a front passage FP4 formed in the front head 4.
The low-temperature side heat exchanger 21 in the passage 19d is connected to the cylinder bore B4 through a rear passage RP1 formed in the rear head 5.
Is communicated with the working space RS of the cylinder bore B1 adjacent to. That is, the working space FS of the cylinder bore B4 and the working space RS of the cylinder bore B1 adjacent to the cylinder bore B4 communicate with each other via the front passage FP4, the passage 19d, and the rear passage RP1, thereby forming one refrigeration cycle.

The communication passages in the claims include front passages FP1 to FP4, rear passages RP1 to RP4 and passage 1
9a to 19d.

The working space FS, the working space RS, the front passages FP1 to FP4, the rear passages RP1 to RP4, and the passages 19a to 19d are filled with, for example, He (helium) as a working gas.

Next, the operation of the Stirling refrigerator will be described.

The swash plate 7 rotates integrally with the rotation of the drive shaft 6, and the pistons P1 to P4 sequentially linearly reciprocate in the cylinder bores B1 to B4 with a phase difference of 90 ° via the shoes S1 and S2.

When the working gas in the working space FS is compressed by the movement of the pistons P1 to P4, and the working gas in the working space RS expands, the circulating water circulating in the high-temperature side heat exchanger 20 is heated and becomes hot water. The circulating water circulating in the low-temperature side heat exchanger 21 is deprived of heat and becomes cold water.

At this time, the working gas in the working space FS of the cylinder bores B1 to B4 flows into the front passages FP1 to FP
4, passages 19a to 19d and rear passages RP1 to RP4
Through the working space RS of the adjacent cylinder bores B1 to B4. When moving, the working gas is deprived of heat by the regenerator 22 and cooled.

The working gas in the working space RS of each of the cylinder bores B1 to B4 passes through the rear passages RP1 to RP4, the passages 19a to 19d, and the front passages FP1 to FP4 to operate the adjacent cylinder bores B1 to B4. Space F
It is sent in S. The working gas removes heat from the regenerator 22 during the movement and is heated.

In this way, the hot water is circulated in the high-temperature side heat exchanger 20 for heating, and the cold water is circulated in the low-temperature side heat exchanger 21 for cooling.

According to the Stirling refrigerator of this embodiment, the following effects can be obtained.

Since the dead volume of the low-temperature side heat exchanger 21 is almost zero, the dead volume of the low-low temperature side heat exchanger 21 is equal to the dead volume of the high-temperature side heat exchanger 20 when the total dead volume is constant. The refrigeration capacity can be improved as compared with when.

Since the outer diameter can be reduced by eliminating the space accommodating the high-temperature side heat exchanger 20, when the outer diameter is the same, the refrigerating capacity can be increased and the cylindrical cylinder body can be formed. A bracket (not shown) for attaching the mounting body 2 to the mounting base is attached to the cylinder body 2.
It can be mounted without protruding too much. At this time, the bracket can be moved away from the heat exchanger, and the amount of heat escaping through the bracket can be suppressed.

The heat transfer area can be increased by increasing the size of the rear head 5 in which the low temperature side heat exchanger 21 is accommodated, and the heat exchange efficiency can be increased.

Since the heat exchanger does not protrude to the side where the drive shaft 6 protrudes, it is not necessary to lengthen the drive shaft 6, and the operation of the refrigerator is stabilized.

In this embodiment, water is used as a heat medium between the heating device and the cooling device, but air may be used, for example. When air is used, the air introduced into the passenger compartment can be cooled directly, so that the cool air can be blown out quickly and the fogging of the window glass can be quickly removed.

Further, in this embodiment, the low-temperature side heat exchanger 21 is arranged on the rear head 5 side where the drive shaft 6 does not protrude. However, the high-temperature side heat exchanger 20 is arranged on the rear head 5 side, and each of the cylinder bores B1 ~ B4 high temperature side heat exchanger 2
0 and the low-temperature side heat exchanger 21 may be alternately arranged on the front head 4 side and the rear head 5 side.

Further, it is possible to make the dead volume small by making the passages small. However, it is not advisable to make all the passages small because the flow loss of the working gas occurs and the cycle performance deteriorates. .

[0080]

As described above, according to the Stirling refrigerator of the first aspect of the present invention, when the total dead volume is constant while maintaining the cycle efficiency, the dead volume of the low-temperature side heat exchanger is increased. The refrigeration capacity is improved as compared with the case where the dead volume of the heat exchanger is equal to the dead volume.

According to the Stirling refrigerator of the second aspect of the present invention, the cycle efficiency can be maintained and the dead volume of the low-temperature side heat exchanger is small. The refrigeration capacity can be improved as compared to when the dead volume is equal to the dead volume of the high-temperature side heat exchanger.

According to the Stirling refrigerator of the third aspect of the present invention, the space for accommodating the high-temperature side heat exchanger can be eliminated and the outer diameter can be reduced. The capability can be enhanced, and a bracket for attaching the cylindrical cylinder body to the mounting base can be mounted without protruding too much from the cylinder body.

Further, the bracket can be kept away from the heat exchanger, and the amount of heat escaping through the bracket can be suppressed.

Further, the heat transfer area can be increased by increasing the size of the rear head accommodating the low-temperature side heat exchanger, and the heat exchange efficiency can be increased.

Further, there is no need to lengthen the drive shaft, and the operation of the refrigerator is stabilized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a Stirling refrigerator according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a conceptual diagram illustrating a swash plate type Stirling refrigerator according to an embodiment of the present invention.

FIG. 4 is a graph showing a result of performing a Stirling cycle calculation using an isothermal analysis model.

[Explanation of symbols]

 Reference Signs List 1 swash plate type Stirling refrigerator 2 cylinder body 3a, 3b cylinder block 4 front head 5 rear head 6 drive shaft 7 swash plate 19a, 19b, 19c, 19c passage (communication passage) 20 high-temperature side heat exchanger 21 low-temperature side heat exchanger 22 Regenerator B1, B2, B3, B4 Cylinder bore FP1, FP2, FP3, FP4 Front passage FS working space RS Working space P1, P2, P3, P4 Piston RP1, RP2, RP3, RP4 Rear passage

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shunichi Furuya 3--13-26 Yayumicho, Higashimatsuyama-shi, Saitama Pref. Inside the Zexel Higashi-Matsuyama Plant (72) Inventor Hiroyuki Kasahara 3--13, Yayumicho, Higashimatsuyama-shi, Saitama No. 26 Inside Zexel Higashimatsuyama Plant

Claims (3)

[Claims] 1. A Stirling refrigerator wherein a dead volume of the low-temperature side heat exchanger is smaller than a dead volume of the high-temperature side heat exchanger. 2. A cylinder body having a plurality of cylinder bores, two cylinder heads coupled to both end faces of the cylinder body, a plurality of pistons slidably housed in the cylinder bore, and inside the cylinder body. A swash plate that rotates integrally with the drive shaft and causes the plurality of pistons to linearly reciprocate in the cylinder bore with a predetermined phase difference; a first working space formed in one of the pistons in the cylinder bore A second working space formed in the other side of the piston in the cylinder bore; a low-temperature side heat exchanger provided in the cylinder body and located near the first working space; A high-temperature heat exchanger that is provided in the vicinity of the second working space; and is disposed between the low-temperature heat exchanger and the high-temperature heat exchanger. A regenerator, the first working space of the cylinder bore, and the second working space of the cylinder bore accommodating a piston driven with the predetermined phase difference with respect to the piston in the cylinder bore. A Stirling refrigerator comprising a communication passage, wherein a dead volume of the low-temperature side heat exchanger is smaller than a dead volume of the high-temperature side heat exchanger. 3. The high-temperature side heat exchanger and the low-temperature side heat exchanger are offset in the direction of the drive shaft to a side where the drive shaft does not project with respect to the swash plate, and the high-temperature side heat exchange is performed. The heat exchanger is located on the side where the drive shaft protrudes, and the low-temperature side heat exchanger is located on the side where the drive shaft does not protrude.
A Stirling refrigerator according to claim 1.