JP2000257568A - Displacement type fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress flow speed raising of an intake stroke to reduce pressure loss of the intake stroke, and improve a performance and a reliability by forming a cylinder and a flat shape of a displacer so as to maximize a capacity of an operation space in a condition sealed on only inflection point of a curve. SOLUTION: An inner circumferential shape of a cylinder for composing a displacement type compressor is formed so as to appear a hollow part in a same shape every 120 deg., and a plurality of circular cone shaped vanes 4 protruded inward are formed on an end part of each hollow part. In a displacer 5 disposed in a cylinder 4, each center O, O' is formed sliding for a predetermined rate ε so as to engage the vane 4b with an inner circumferential wall 4a whose curvature is larger than that of the vane 4b. When a driving shaft 6 is rotated, the displacer 5 is revolved without self-rotating, a plurality of operating chambers 9 are sectioned around a center O of the displacer 5, operating gas is sucked from an intake port 7a, and compressed. And then, it is delivered from a delivery port 8a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump, a compressor, an expander, and the like, and more particularly, to a positive displacement fluid machine.

[0002]

2. Description of the Related Art A reciprocating type fluid machine which moves a working fluid by repeating a reciprocating motion of a displacer in a cylindrical cylinder has been used as a positive displacement type fluid machine for a long time.
A rotary (rolling piston type) fluid machine for moving a working fluid by eccentric rotation of a cylindrical displacer in a cylindrical cylinder, a pair of fixed scrolls having a spiral wrap standing upright on an end plate and orbiting 2. Description of the Related Art A scroll-type fluid machine that moves a working fluid by engaging a scroll and orbiting a orbiting scroll is known.

[0003] Reciprocating fluid machines have the advantage of being easy and inexpensive to manufacture because of their simple structure, but the stroke from the end of suction to the end of discharge is as short as 180 ° in terms of the rotation angle of the rotating shaft. The problem is that the flow rate of the discharge stroke becomes faster, the performance is reduced due to the increase in pressure loss, and the reciprocating motion of the displacer makes it impossible to completely balance the unbalanced inertial force of the rotating shaft system, resulting in vibration and noise. There is a problem that is large.

[0004] In the rotary type fluid machine, although the stroke from the end of suction to the end of discharge is 360 ° in the rotation angle of the rotating shaft, the problem that the pressure loss in the discharge stroke increases is smaller than that of the reciprocating type fluid machine. Since the gas is discharged once per rotation of the shaft, the fluctuation of the gas compression torque is relatively large, and there is a problem of vibration and noise as in the reciprocating fluid machine.

Further, in the scroll type fluid machine, the stroke from the end of the suction to the end of the discharge requires a rotation angle of the rotary shaft of 360 °.
The pressure loss in the discharge stroke is small due to the long length as described above (usually about 900 ° for those practically used for air conditioning). In addition, since a plurality of working chambers are generally formed, the fluctuation of the gas compression torque during one rotation is also small. There is an advantage that vibration and noise are small. However, it is necessary to manage the clearance between the spiral wrap in the lap meshing state and the clearance between the end plate and the tip of the lap, so that high-precision processing must be performed and the processing cost is high. There is. Further, there is a problem that the stroke from the end of suction to the end of discharge is as long as 360 ° or more in terms of the rotation angle of the rotating shaft, and the longer the period of the compression stroke, the more internal leakage increases.

By the way, the displacer for moving the working fluid does not rotate relative to the cylinder into which the working fluid is sucked, but revolves around a substantially constant radius, that is, rotates to convey the working fluid. Japanese Patent Application Laid-Open No. 55-23353 (Document 1), U.S. Pat. No. 2,112,890 (Document 2), Japanese Patent Application Laid-Open No. 5-202869 (Document 3), and Japanese Patent Application Laid-Open No. 6-28
No. 0758 (Document 4). The displacement type fluid machine proposed here has a plurality of members (vanes).
Is composed of a displacer having a petal shape extending radially from the center, and a cylinder having a hollow portion substantially similar to the displacer, and the displacer moves in the cylinder to move the working fluid. Things.

[0007] The positive displacement fluid machines disclosed in the above-mentioned documents 1 to 4 do not have a reciprocating portion unlike the reciprocating type, so that the imbalance of the rotating shaft system can be balanced. For this reason, vibration is small, and furthermore, since the relative sliding speed between the displacer and the cylinder is small, friction loss can be relatively reduced.

However, the stroke from the end of suction to the end of discharge of each working chamber formed by the plurality of vanes and cylinders constituting the displacer takes about 180 ° (210 °) at the rotation angle θc of the rotating shaft. (About half of the rotary type and about the same as the reciprocating type), there is a problem that the flow velocity of the fluid in the discharge stroke increases, the pressure loss increases, and the performance decreases. Further, in the fluid machines disclosed in these documents, the rotation angle of the rotating shaft from the end of suction to the end of discharge of each working chamber is small, and the next (compression) stroke starts after the discharge of the working fluid ends ( There is a time lag (time lag) until the end of inhalation, and the working chamber from the end of inhalation to the end of discharge is formed to be biased around the rotation axis. As a reaction force from the compressed working fluid, the rotation moment of rotating the displacer itself acts excessively on the displacer, and the reliability problem such as vane friction and wear tends to occur. is there.

A positive displacement type fluid machine proposed in Japanese Patent Application No. 9-16233 (Document 5) has a capacity to convey a working fluid by a swiveling motion of a displacer, as in Documents 1 to 4. Although it is a type fluid machine, the stroke from the end of suction to the end of discharge of each working chamber is set to about 270 ° to 360 ° at the rotation angle θc of the rotating shaft, and the pressure loss in the discharge stroke can be reduced. ing.

[0010]

The fluid machine disclosed in Document 5 has a structure in which the working chamber is divided into two until the suction is completed, and the working chamber becomes one at the same time as the start of the compression and the compression stroke proceeds. Has become. The two working chambers suck fluid from different suction ports, and one of the working chambers cannot have a sufficient suction passage due to its structure, so that the flow velocity in the suction stroke increases and the pressure loss increases. There is a problem that the performance is deteriorated. An object of the present invention is to provide a high-performance and highly reliable positive displacement fluid machine which suppresses an increase in flow velocity in a suction stroke and reduces pressure loss in a suction stroke in the positive displacement fluid machine of Document 5. .

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cylinder having an inner wall formed by a continuous curved surface between end plates, and an outer wall provided to face the inner wall of the cylinder. A displacement type fluid machine including a displacer that forms a plurality of spaces by the inner wall, the outer wall, and the end plate when swiveling, in the plurality of spaces, a seal is formed only at an inflection point of the curve. This is achieved by matching the maximum volume of the space with the state to be sealed with the state of being sealed only at the inflection point.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The features of the present invention described above will be further clarified by the following embodiments. Hereinafter, one of the present inventions
Embodiments will be described with reference to the drawings. First, the structure of a positive displacement fluid machine according to one embodiment of the present invention will be described with reference to FIGS. FIG. 1A is a vertical cross-sectional view (A-A cross-sectional view of FIG. 1B) showing a main part of a hermetic compressor when a positive displacement fluid machine according to an embodiment of the present invention is used as a compressor. 1 (b) is a plan view showing a state in which a compression chamber is formed as viewed from the direction of the arrow BB in FIG. 1 (a), FIG. 2 is an operation principle diagram of a positive displacement compression element, and FIG. 3 is an embodiment of the present invention. It is a longitudinal cross-sectional view of a hermetic compressor when a positive displacement type fluid machine is used as a compressor.

In FIG. 1, a positive displacement element 1 and a motor-driven element 2 for driving the same are provided in a closed container 3 (not shown).
Is stored. The details of the positive displacement compression element 1 will be described. FIG. 1B shows a three-row wrap in which three sets of the same contour shape are combined. The inner peripheral shape of the cylinder 4 is
The hollow portion is formed such that the same shape appears every 120 ° (center O ′). At the end of each individual hollow,
It has a plurality of inwardly projecting (in this case, three wraps, three of which are present) vanes 4b having a substantially arc shape. The displacer 5 is disposed inside the cylinder 4 and has a center shifted from each other by ε so as to mesh with the inner peripheral wall 4a (a portion having a larger curvature than the vane 4b) and the vane 4b of the cylinder 4. . In addition, cylinder 4
And the center O of the displacer 5
A gap having a constant width is formed as a basic shape between the two contour shapes.

Next, the operation principle of the positive displacement compression element 1 will be described with reference to FIG.
And FIG. The symbol O is the center of the displacer 5, and the symbol O 'is the center of the cylinder 4 (or the drive shaft 6). Symbols a, b, c, d, e, and f represent contact points (seal points) at which the inner peripheral wall 4a and the vane 4b of the cylinder 4 mesh with the displacer 5. Here, looking at the inner peripheral contour shape of the cylinder 4, three combinations of the same curves are connected smoothly in succession at three locations.

Focusing on one of these, the inner peripheral wall 4
a, the curve forming the vane 4b can be regarded as one thick vortex curve (the tip of the vane 4b is considered to be the start of the vortex), and the inner wall curve (ga) forms the curve. The winding angle, which is the sum of the respective arc angles, is approximately 360 ° (meaning that the design concept is 360 °, but the value is not exactly equal to the value due to a manufacturing error or the like. The same applies to the following).
The outer wall curve (gb) is a vortex curve having a winding angle of about 360 °. As described above, the one inner peripheral contour shape is formed from the inner wall curve and the outer wall curve. Approximately equal pitch on these two curved circles (120
°), and the outer wall curve and the inner wall curve of the adjacent spiral body are connected by a smooth connection curve (bb ′) such as an arc to form the entire inner peripheral contour shape of the cylinder 4. . The outer peripheral shape of the displacer 5 is the same as that of the cylinder 4.
It is configured on the same principle.

The spiral body composed of three curves is arranged at substantially equal pitches (120 °) on the circumference. This is for the purpose of uniformly distributing the load associated with the compressing operation and the ease of manufacture. In particular, when these do not matter, the pitch may be irregular.

The compression operation of the cylinder 4 and the displacer 5 configured as described above will be described with reference to FIG. Reference numeral 7a denotes a suction port, and 8a denotes a discharge port, which are respectively provided on end plates corresponding to three places. By rotating the drive shaft 6, the displacer 5 revolves around the turning radius ε (= OO ′) without rotating around the center O ′ of the cylinder 4 on the fixed side, and the center of the displacer 5 is rotated.
Around the O, a plurality of working chambers 9 (in a plurality of hermetically sealed spaces surrounded by a cylinder inner peripheral contour (inner wall) and a displacer outer contour (side wall)), suction is completed and a compression (discharge) process is performed. Refers to space.

That is, a space in a period from the end of suction to the end of discharge. If the above-mentioned winding angle is 360 ° only, this space disappears at the end of compression, but at that moment, the suction ends, so this space is counted as one. However, when used as a pump, a space that communicates with the outside via the discharge port 8a is formed (in the present embodiment, there are always three working chambers). One working chamber surrounded by contact points a and b and hatched (separated into two at the end of suction, but immediately after the compression stroke is started, these two working chambers are connected and become one) ) Will be described.

FIG. 2A shows a state in which the suction of the working gas from the suction port 7a into the working chamber is completed. FIG. 2 shows a state in which the drive shaft 6 is rotated 90 ° clockwise from this state.
FIG. 2 (3) shows a state in which the rotation progresses and rotates 180 ° from the beginning, and FIG. 2 (4) shows a state in which the rotation further advances and rotates 270 ° from the beginning. When rotated 90 ° from FIG. 2 (4), it returns to the initial state of FIG. 2 (1). As a result, the working chamber 9 decreases its volume as the rotation progresses, and the discharge port 8a is closed by the discharge valve 10 (shown in FIG. 1), so that the working fluid is compressed. When the pressure in the working chamber 9 becomes higher than the external discharge pressure, the discharge valve 10 automatically opens due to the pressure difference, and the compressed working gas is discharged through the discharge port 8a.

The rotation angle of the drive shaft 6 from the end of suction (compression start) to the end of discharge is 360 °, and the next suction stroke is prepared while each compression and discharge stroke is performed.
The end of the discharge is the start of the next compression. For example, contacts a and d
Paying attention to the space formed by, the suction has already been started from the suction port 7a at the stage of FIG. 2A, and the volume increases as the rotation proceeds, and when the state of FIG. Is divided. Fluid corresponding to this divided amount is supplemented from the space formed by the contacts b and e.

The manner of this supplement will be described in detail. FIG.
In the space formed by the contacts a and d adjacent to the working chamber formed by the contacts a and b in the state (1), suction has started. This space is once expanded as shown in FIG. 2 (3), and then divided as shown in FIG. 2 (4). Therefore, not all the fluid in the space formed by the contacts a and d is compressed in the space formed by the contacts a and b. The same amount of fluid as the volume of the fluid that has been divided and not taken into the space formed by the contacts a and d is shown in FIG.
In (4), the space formed by the contacts b and e in the suction stroke is divided as shown in FIG. 2A, and flows into the space formed by the contacts e and b near the discharge port. Is filled by the flowing fluid.

This is because the wraps are arranged at a uniform pitch as described above. That is, the displacer 5
Also, since the shape of the cylinder 4 is formed by repeating the same contour shape, substantially the same amount of fluid can be compressed even if any working chamber obtains fluid from different spaces. Although it is possible to perform processing so that the volumes formed in the respective spaces are equal even if the pitch is not uniform, the productivity is poor. In any of the prior arts of Documents 1 to 4 described above, the space in the suction stroke is closed and the internal fluid is compressed and discharged as it is. Performing the compression operation while a certain space is divided is one of the features of the present embodiment.

As described above, the working chambers that perform a continuous compression operation are distributed at substantially equal pitches around the drive bearing 5a located at the center of the displacer 5, and each of the working chambers has a phase. And the compression is performed. That is,
Focusing on one space, the rotation angle of the drive shaft is 360 ° from the suction to the discharge, but in the present embodiment, three working chambers are formed, and these discharge each with a phase shifted by 120 °. When operated as a compressor that compresses a refrigerant as a fluid, the refrigerant is discharged three times during a rotation angle of the drive shaft of 360 °.

If the space at the moment when the compression operation is completed (the space surrounded by the contact points a and b) is regarded as one space, if the winding angle is 360 ° as in this embodiment, any compression Even in the machine operating state, the space in the suction stroke and the space in the compression stroke are designed to be alternated, so that the next compression stroke is started immediately after the compression stroke is completed. Fluid can be compressed smoothly and continuously.

Next, a compressor incorporating the volumetric compression element 1 having such a shape will be described with reference to FIGS. In FIGS. 1 and 3, in addition to the cylinder 4 and the displacer 5 described above in detail, the positive displacement element 1 is provided with a crank 6 on a drive bearing 5a at the center of the displacer 5.
a driving shaft 6 for driving the displacer 5 by fitting into the main bearing 11, a main bearing 11 and a sub-bearing 8 for supporting the driving shaft 6, a partition plate 7 for closing both ends of the cylinder 4, and the main bearing 11
, A suction port 11a formed in the partition plate 7, a discharge port 8a formed in an end plate of the sub-bearing 8, and a discharge port 8a.
Has a discharge valve 10 that opens and closes with a differential pressure. 12 is an auxiliary bearing 8
And a discharge cover for integrally forming the discharge chamber 8b.

The electric element 2 includes a stator 2a and a rotor 2b, and the rotor 2b is fixed to the drive shaft 6 by shrink fitting or the like. The electric element 2 is constituted by a brushless motor for improving electric motor efficiency, and is driven and controlled by a three-phase inverter. However, 2 may be another motor type, for example, a DC motor or an induction motor.

Numeral 13 denotes lubricating oil stored at the bottom of the closed container 3, in which the lower end of the drive shaft 6 is immersed.
14 is a suction pipe, 15 is a discharge pipe, 9 is a cylinder 4
The working chamber is formed by the engagement of the inner peripheral wall 4a and the vane 4b with the displacer 5.

The flow of the working gas (refrigerant gas) when the positive displacement fluid machine in this embodiment is used as an air conditioning compressor will be described with reference to FIGS. As shown by the arrow (solid line) in the figure, the working gas that has entered the closed casing 3 through the suction pipe 14 enters the suction chamber 11a formed by the main bearing 11 and the partition plate 7, and the suction port 7a. Into the positive displacement compression element 1, where the rotation of the drive shaft 6 causes the displacer 5 to perform a swiveling motion and to be compressed by reducing the volume of the working chamber.

The compressed working gas passes through a discharge port 8a formed in the end plate of the auxiliary bearing 8 and pushes up the discharge valve 10 to enter the discharge chamber 8b.
6. In the order of the electric element 2, the liquid flows out through the discharge pipe 15 to the outside. Here, the number of the discharge passages 16 may be any number as long as there is no problem in pressure loss or space.
In this embodiment, the structure of the discharge passages 16 is the same as the number of the discharge ports 8a.

The lubricating oil 13 stored inside is sent to each sliding portion from the bottom through a hole provided inside the drive shaft 6 by a differential pressure or lubrication of a centrifugal pump to be lubricated. This part is also supplied to the inside of the working chamber through the gap.

Here, an example of a method of forming the contours of the displacer 5 and the cylinder 4 which are the main components constituting the positive displacement compression element 1 of the present invention will be described with reference to FIGS. I will give you an example). FIG. 4 (a)
(B) is an example of the shape of the displacer whose planar shape is formed by a combination of arcs as an example, (a) is a plan view, and (b) is a side view. FIGS. 5A and 5B show FIG.
(A) is a plan view and (b) is a side view of an example of a cylinder shape which meshes with a pair of displacers shown in FIG. FIG. 6 shows the center of the displacer shown in FIG.
FIG. 6 is a diagram in which O and a center O ′ of the cylinder shown in FIG.

In FIG. 4 (a), in the planar shape of the displacer, three identical contours are continuously connected around the center O (center of the equilateral triangle IJK). The contour shape is formed by a total of nine arcs from the radius R1 to the radius R9, and the points p, q, r, s, t, u, v, and
w, x, and y are connection points of arcs having different radii.

The curve pq is an arc of radius R1, where point p is at a distance R9 from vertex I. Curve qr is an arc of radius R2 having a center on the extension of a straight line connecting the contact point q and the center of radius R1, curve rs is an arc of radius R3 having a center on an extension of a straight line connecting the contact point r and the center of radius R2, Curve st
Is an arc of a radius R4 having a center on a straight line connecting the contact s and the center of the radius R3. The curve tu is an arc of a radius R5 having a center on an extension of a straight line connecting the contact point t and the center of the radius R4,
The curve uv is an arc having a radius R6 having a center on an extension of a straight line connecting the contact point u and the center of the radius R5, and the curve vw is a radius R having a center on an extension line of a straight line connecting the contact point v and the center of the radius R6.
7, a curve wx is an arc having a radius R8 having a center on a straight line connecting the contact point w and the center of the radius R7, and a curve xy is a radius R9 having a vertex J on the straight line connecting the contact point x and the center of the radius R8. Is an arc.

The radii R1, R2, R3, R4, R5
The angles of the respective arcs of R6, R7, R8, and R9 are determined by the condition that the contacts are smoothly connected (the inclination of the tangent line at the contacts is the same). When the contour shape from the point p to the point y is rotated counterclockwise around the centroid O by 120 °, the point p overlaps the point y. When the contour shape is further rotated by 120 °, the contour shape around the entire circumference is completed. Thereby, the planar shape of the displacer is obtained, and the displacer is constituted by giving the thickness h.

When the plane shape of the displacer is determined, when the displacer makes a revolving motion with a revolving radius ε, the contour of the cylinder that meshes with the displacer is outside the curve constituting the contour of the displacer as shown in FIG. An offset curve having a normal distance of ε is obtained.

The outline shape of the cylinder will be described with reference to FIG. The triangle IJK is the same equilateral triangle as in FIG. The contour shape is formed by a total of nine arcs like the displacer, and the points p ′, q ′, r ′, s ′, t ′,
u ′, v ′, w ′, x ′, y ′ are connection points of arcs having different radii. The curve p′q ′ is an arc of radius (R1 + ε), where the point p ′ is at a distance (R9 + ε) from the vertex I. The curve q′r ′ has a radius (R2−2) having a center on an extension of a straight line connecting the contact point q ′ and the center of the radius (R1 + ε).
The arc of ε) and the curve r ′s ′ have a contact point r ′ and a radius (R2−
radius (R) having a center on an extension of a straight line connecting the centers of ε)
The arc of 3-ε) and the curve s′t ′ have s ′ and a radius (R3-
Radius (R4-ε) with center on straight line connecting centers of ε)
Is an arc. The curve t'u 'has a contact point t' and a radius (R4-
radius (R) having a center on an extension of a straight line connecting the centers of ε)
5 + ε), the curve u′v ′ is formed by the contact point u ′ and the radius (R5
+ Ε) is an arc of a radius (R6 + ε) having a center on the extension of a straight line connecting the center of the curve, and a curve v′w ′ is a radius (R7 + ε) having a center on an extension of a straight line connecting the contact point v ′ and the center of the radius (R6 + ε). ), A curve w′x ′ is an arc of a radius (R8 + ε) having a center on a straight line connecting the contact point w ′ and the center of the radius (R7 + ε), and a curve x′y ′ is a curve of the contact point x ′ and the radius (R8 + ε). This is an arc of (R9 + ε) centered on vertex J on a straight line connecting the centers.

Note that the radii (R1 + ε), (R2-ε),
(R3-ε), (R4-ε), (R5 + ε), (R6 +
The angles of the arcs of (ε), (R7 + ε), (R8 + ε), and (R9 + ε) are determined by the condition that the connection is made smoothly at each contact (the inclination of the tangent line at the contact is the same) as in the displacer. If the contour from point p 'to point y' is rotated counterclockwise around the center O 'by 120 °, the point p' coincides with point y '. Complete. Thereby, the planar shape of the cylinder is obtained. The thickness H of the cylinder is slightly larger than the thickness h of the displacer.

FIG. 6 is a view showing a part of the center O of the displacer and the center O 'of the cylinder overlapped. The gap formed between the displacer and the cylinder is set to ε equal to the turning radius. It is desirable that this gap be ε over the entire circumference. However, within a range where the working chamber formed by the outer peripheral contour of the displacer and the inner peripheral contour of the cylinder operates normally, for some reason, this relationship is not satisfied. Even if there is a place that collapses, it does not matter.

Although the method of forming the contours of the outer wall of the displacer and the inner wall of the cylinder by combining a plurality of arcs has been described here, the present invention is not limited to this, and the present invention is not limited to this. A similar contour shape can be formed by a combination of curves.

Next, a method for calculating the volume of the positive displacement type compression element of the present invention thus configured will be described with reference to FIG. FIG. 7A is a diagram in which the center O of the displacer and the center O ′ of the cylinder shown in FIGS. 4 and 5 are overlapped (one set). As is clear from the above,
A uniform band-like space having a width of the turning radius ε is formed between the displacer and the cylinder. Sa and Sa 'and Sb and S
b ′ indicates the seal point between the displacer and the cylinder at the end of suction, and when they match each other, they constitute a working chamber at the end of suction.

As the drive shaft rotates and the compression stroke proceeds, the seal points approach each other, and become g and g ', respectively, at the same time as the end of compression, and the seal points overlap. The seal points of the rotation angles θ1 and θ1 + θ2 of the arbitrary drive shafts are defined as θ1, θ1 + θ2, which are the arc angles from the seal point at the end of suction, and are a and a ′, b and b ′, c and c ′, and d and d ′. expressed.
The working chamber at this time is formed as shown in FIG. There is a moment when the distance L between the sealing points once becomes zero between the rotation angle θ1 and θ1 + θ2, and before and after this moment, the method of calculating the volume of the working chamber differs.

Assuming that the projected area of the working chamber before the distance between the seal points becomes zero is Ap1 and that after it becomes zero is Ap2,
As shown in FIG. 7C, Ap1 and Ap2 are related to Ap1, a band-shaped area Ab1 surrounded by the sealing points a and a 'and b and b', a distance L1 between the sealing points and a turning radius ε. And Ac1 expressed by the product of Regarding Ap2, a band-shaped area Ab2 surrounded by the seal points c and c ′ and d and d ′.
And Ac2 expressed by the product of the distance L2 between the two seal points and the turning radius ε. Then, the cylinder height H is added to the projection area Ap1 or Ap2.
By multiplying by (displacer height h), the volume Vi of the working chamber at an arbitrary rotation angle θ of the drive shaft can be obtained.

Next, the relationship between the rotation angle of the drive shaft at the end of suction and the rotation angle of the drive shaft at which the volume Vi calculated as described above becomes the maximum will be described with reference to FIG. FIG. 8 is a diagram showing a state in which the suction has been completed, and the hatched portion is the working chamber. “a”, “b” and “g” indicate the sealing points between the displacer 5 and the cylinder 4 at this time. Also,
g is also the point where a and b overlap at the same time as the end of compression. As described above, at the end of inhalation, the working chamber 9 is divided into two (here, the two divided working chambers are referred to as a working chamber α and a working chamber β, respectively). Considering the change in volume separately (how to separate will be described later), the phase difference between the rotation angle at the end of inhalation and the rotation angle at which the volume Vi of each working chamber is maximized is expressed as a The angle θspα between the line perpendicular to the straight line connecting g and g and the normal direction of the curve where a is located, and for the working chamber β, the line perpendicular to the straight line connecting b and g and the curve where b is located It can be represented by an angle θspβ with respect to the normal direction. In other words, in the positive displacement compression element according to the embodiment of the present invention, θspα and θspβ can be set according to the contour shape.

Next, the suction passage in the displacement type compression element according to the embodiment of the present invention will be described with reference to FIG. FIG.
FIG. 3 is an enlarged view of a suction port section in FIG. 2. here,
The arrow (thick line) indicates the flow of the working gas. As described above, the space formed by the contact points a and d has begun to be sucked, and the space is once expanded as shown in FIG. Divided into β. The working chambers α and β merge with adjacent spaces,
Enter the compression process. That is, compression is performed by merging with the spaces in which the working gas is sucked from the different suction ports.

FIG. 9 shows the latter half of the suction stroke.
Referring to (3) and FIG. 9 (4), the suction port 7a is sufficiently open for the suction passage to the working chamber α.
On the other hand, the suction passage to the working chamber β is formed by the distance Ls between the displacer 5 and the vane 4b and the height of the displacer 5, where the displacer 5 and the vane 4b approach each other at the suction port 7a. The projected area is a suction passage to the working chamber β. The displacer 5 is further moved from the state shown in FIG.
approaching b. That is, due to the structure of the positive displacement compression element of the present embodiment, the suction passage to the working chamber β cannot be secured in the latter half of the suction stroke.

The positive displacement type fluid machine described in Japanese Patent Application No. 9-16233 (Reference 5) is based on the positive displacement type compression element of the embodiment of the present invention described above, and its basic principle such as operating principle and contour shape. The structure is almost the same, and the working chamber β cannot have a suction passage due to its structure. Further, the volume change characteristic is focused only on the working chamber in the compression stroke, and as described above, the volume change characteristic is not divided into two working chambers and considered.

The volume change characteristics of the positive displacement type fluid machine of Document 5 will be described with reference to FIGS. FIG. 10A is a diagram illustrating an example of a compression element of the positive displacement fluid machine of Document 5. FIG. 10B is a diagram showing the volume change characteristic of the compression element of FIG. 10A (represented by the ratio of the working chamber volume Vs at the end of suction to the above-described working chamber volume Vi). The horizontal axis is the rotation angle θ of the drive shaft, from −360 ° to 0 ° is the suction stroke, and from 0 ° to 3 °.
60 ° is the compression stroke. Here, the volume change characteristics are shown for each of the working chambers α and β. How to divide the working chambers α and β will be described with reference to FIG. The compression stroke is divided by a virtual line 9a connecting the seal points g at the end of the compression stroke (FIG. 11A), and the suction stroke is divided by a virtual line 9b connecting the seal points a at the end of the suction stroke. (FIG. 11B).

Looking at the volume change characteristics of the working chamber β, the maximum volume is after the end of suction (θspβ ≒ 60 °). As described above, in the compression element in which the maximum volume of the working chamber β in which the suction passage cannot be secured in the latter half of the suction is after the end of the suction, the suction flow velocity increases in the latter half of the suction stroke, the pressure loss at the suction port increases, and the performance decreases. Let me do it.

Next, the volume change characteristics of the positive displacement compression element according to the embodiment of the present invention will be described with reference to FIGS.
FIG. 12A is a view showing a positive displacement compression element according to an embodiment of the present invention. FIG. 12B is a diagram showing the volume change characteristic of FIG. FIG. 13 is a diagram showing how the working chambers α and β are divided. (The method of division is the same as in the case of Reference 5 above.)

In view of the volume change characteristics, the maximum volume of the working chamber β where the suction passage cannot be secured due to the structure substantially coincides with the suction end timing. Thus, by adjusting the maximum volume of the working chamber β for which the suction passage cannot be secured to the suction end time,
The flow velocity of suction of the working gas into the working chamber β can be reduced, the pressure loss at the suction port can be reduced, and the fluid loss during the suction stroke can be reduced to improve the performance.

The working chamber α has a maximum volume of θspα ≒ 30 ° in both Reference 5 and the present invention after the end of suction. This is because, when θspα is reduced, the seal section at the arc portion where the arc radius at the end of the discharge stroke becomes smaller becomes longer.

Next, FIG. 14 shows the flow rate of the intake gas to the working chamber β calculated from the volume change characteristics of the positive displacement compression elements shown in FIGS. 10 and 12. Here, the rotation speed is 3600 min-
Is one. Thereby, in the displacement type compression element according to the embodiment of the present invention, since the maximum volume of the working chamber β, which cannot secure a suction passage due to its structure, is matched with the end of suction, the suction flow velocity becomes slow and pressure loss can be reduced. .

In the above embodiment, the maximum volume of the working chamber β is set at the end of the suction. However, by reducing the change in the volume of the working chamber β near the end of the suction,
It is also possible to obtain the above effects.

FIG. 15 is an explanatory diagram of the load and the moment acting on the displacer 5 in the present embodiment.
The symbol θ is the rotation angle of the drive shaft 6, and ε is the turning radius. With the compression of the working gas, the displacer 5 exerts a tangential force Ft perpendicular to the eccentric direction and a radial force Fr corresponding to the eccentric direction due to the internal pressure of each working chamber as shown in the drawing. F
The resultant force of t and Fr is F. The displacement of the resultant force F from the center O of the displacer 5 (the length l of the arm) causes a rotation moment M (= F · l) for rotating the displacer. The rotation moment M is supported by contact points c and f of the displacer 5 and the cylinder 4.
Are the reaction force R1 and the reaction force R2. In the present invention, the rotation moment M is always received at two or three contacts near the suction port 7a, and no reaction force acts on the other contacts.

The displacement type compression element 1 of the present invention comprises a crank 6 a of a drive shaft 6 fitted to the center of a displacer 5.
The working chambers in which the rotation angle of the drive shaft 6 from the end of the suction to the end of the discharge is substantially 360 ° at a substantially equal pitch are distributed around, so that the point of action of the resultant force F is It can be close to the center O, and the moment M
The arm 1 has a reduced length l and the rotation moment M can be reduced. Therefore, the reaction force R1 and the reaction force R2 are reduced. Further, as can be seen from the positions of the contacts c and f, the sliding portion between the displacer 5 and the cylinder 4 receiving the rotation moment M is set so as to be near the suction port 7a of the working gas having a low temperature and a high oil viscosity. Therefore, an oil film on the sliding portion is secured, and a highly reliable positive displacement fluid machine that solves the problems of friction and wear can be provided.

In the displacement type compression element of the present embodiment shown in FIG. 12, the radius of curvature of the sliding portion receiving the rotation moment M is increased, so that the contact surface pressure of the sliding portion can be reduced.

FIG. 16 shows that the contact surface pressure P1 of the displacement type compression element shown in FIG. 12 when receiving the rotation moment at the contact point c is changed to the maximum contact surface pressure Pmax of the displacement type compression element shown in FIG. Divided by The calculation conditions are suction pressure Ps = 0.2 MPa and discharge pressure Pd = 3.0 MPa. Accordingly, in the positive displacement compression element according to the present embodiment in which the maximum volume of the working chamber β is substantially matched with the end of suction, the radius of curvature of the sliding portion receiving the rotation moment is increased.
For this reason, the contact surface pressure of the sliding portion can be reduced, reliability can be improved, and mechanical loss can be reduced, so that a high-performance positive displacement fluid machine can be provided.

FIG. 17 shows an air conditioning system to which the positive displacement fluid machine of the present invention is applied. This cycle is a heat pump cycle capable of cooling and heating, and includes the positive displacement compressor 17, the outdoor heat exchanger 18 and its fan 18a, the expansion valve 19, the indoor heat exchanger 20 and its components described in FIG. Fan 2
0a, a four-way valve 21. A chain line 22 indicates an outdoor unit, and 23 indicates an indoor unit. The positive displacement compressor 17 operates according to the operation principle diagram shown in FIG. 2, and operates the working fluid (for example, Freon HCFC) between the cylinder 4 and the displacer 5 by starting the positive displacement compressor 17.
22, R407C, R410A, etc.).

In the case of the cooling operation, the compressed high-temperature and high-pressure working gas is supplied from the discharge pipe 15 through the discharge pipe 15 as indicated by the broken line arrow.
Flows into the outdoor heat exchanger 18 through the
8a, the heat is radiated and liquefied by the blowing action, and is throttled by the expansion valve 19;
After being adiabatically expanded to a low temperature and low pressure, the indoor heat exchanger 20 absorbs indoor heat and gasifies the heat, and then is sucked into the positive displacement compressor 17 via the suction pipe 14. On the other hand, in the case of the heating operation, as indicated by the solid line arrow, it flows in the opposite direction to the cooling operation, and the compressed high-temperature and high-pressure working gas flows through the discharge pipe 15
Flows into the indoor heat exchanger 20 through the
0a, the heat is radiated into the room by the blowing action, liquefied, and the expansion valve 19
After being adiabatically expanded by adiabatic expansion to a low temperature and a low pressure, the heat is absorbed by the outdoor heat exchanger 18 from outside air to be gasified, and then sucked into the positive displacement compressor 17 through the suction pipe 14.

FIG. 18 shows a refrigeration system equipped with the positive displacement fluid machine of the present invention. This cycle is frozen (cooling)
This is a dedicated cycle. In the figure, 24 is a condenser, 2
4a is a condenser fan, 25 is an expansion valve, 26 is an evaporator, 2
6a is an evaporator fan. By activating the positive displacement compressor 17, the working fluid is compressed between the cylinder 4 and the displacer 5, and the compressed high-temperature and high-pressure working gas flows from the discharge pipe 15 to the condenser 2 as shown by a solid arrow.
4, the heat is radiated and liquefied by the blowing action of the fan 24 a, squeezed by the expansion valve 25, adiabatically expanded to a low temperature and low pressure, and endothermic gasified by the evaporator 26.
, And is sucked into the positive displacement compressor 17. Here, FIG.
7 and 18 both incorporate the positive displacement fluid machine of the present invention, so that a highly reliable refrigeration / air-conditioning system with excellent energy efficiency, low vibration and low noise can be obtained.

In the embodiments described above, a compressor and a pump have been described as examples of the positive displacement fluid machine. However, the present invention can be applied to an expander and a power machine. Further, in the present invention, one (cylinder side) is fixed and the other (displacer) performs a revolving motion without rotating at a substantially constant turning radius, but is relatively equivalent to the above motion. The present invention can also be applied to a double-rotation type positive displacement fluid machine that has a simple movement form.

[0062]

As described above in detail, the volume change characteristic of the working chamber β where the suction passage of the working gas cannot be secured due to the structure is set by setting θspβ so as to match the maximum volume with the end of suction. A positive displacement type fluid machine with improved performance and high reliability can be obtained. In addition, by mounting such a positive displacement fluid machine on a refrigeration cycle, a highly reliable refrigeration / air-conditioning system with excellent energy efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view and a plan view of a compression element of a hermetic compressor in which a positive displacement fluid machine according to the present invention is applied to a compressor.

FIG. 2 is an explanatory view of the operation principle of the positive displacement fluid machine according to the present invention.

FIG. 3 is a longitudinal sectional view of a positive displacement fluid machine according to the present invention.

FIG. 4 is a diagram showing a contour configuration method of a displacer of the positive displacement fluid machine according to the present invention.

FIG. 5 is a diagram showing a method of forming a contour of a cylinder of the positive displacement fluid machine according to the present invention.

FIG. 6 is a diagram in which the displacer and the cylinder shown in FIGS. 4 and 5 are superimposed.

FIG. 7 is an explanatory diagram of a volume calculation method of the positive displacement fluid machine according to the present invention.

FIG. 8 is a diagram showing the relationship between the rotation angle of the drive shaft at the end of suction and the rotation angle of the drive shaft having the maximum volume.

FIG. 9 is an enlarged view of a suction port portion in FIG. 2;

FIG. 10 is a diagram showing a volume change characteristic of the working chamber of the positive displacement fluid machine in which the maximum capacity of the working chamber β is after the end of suction.

11 is a working chamber α of the positive displacement fluid machine shown in FIG.
FIG. 4 is an explanatory view showing how to divide a working chamber β.

FIG. 12 is a diagram showing a volume change characteristic of a working chamber of the positive displacement fluid machine according to the present invention.

13 is a working chamber α of the positive displacement fluid machine shown in FIG.
FIG. 4 is an explanatory view showing how to divide a working chamber β.

FIG. 14 is a diagram showing a change in suction flow rate of the positive displacement fluid machine according to the present invention.

FIG. 15 is an explanatory diagram of a load and a rotation moment acting on a displacer of the positive displacement fluid machine in the present invention.

FIG. 16 is a diagram showing a change in contact surface pressure at a sliding portion between a displacer and a cylinder of a positive displacement fluid machine according to the present invention.

FIG. 17 is a diagram showing an air conditioning system to which the positive displacement compressor of the present invention is applied.

FIG. 18 is a diagram showing a refrigeration system to which the positive displacement compressor of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Displacement type compression element 2 Electric element 2a Stator 2b Rotor 3 Airtight container 4 Cylinder 4a Inner peripheral wall 4b Vane 5 Displacer 5a Bearing 6 Drive shaft 6a Crank part 7 Partition plate 7a Suction port 8 Secondary bearing 8a Discharge port -G 8b discharge chamber 9 working chamber 9a virtual line 10 discharge valve 11 main bearing 11a suction chamber 12 discharge cover 13 lubricating oil 14 suction pipe 15 discharge pipe 16 discharge passage 17 positive displacement compressor 18 outdoor heat exchanger 18a fan 19 expansion valve Reference Signs List 20 indoor heat exchanger 20a fan 21 four-way valve 22 outdoor unit 23 indoor unit 24 condenser 24a condenser fan 25 expansion valve 26 evaporator 26a evaporator fan O displacer center O 'cylinder center

 ──────────────────────────────────────────────────の Continuing on the front page (72) Masahiro Takebayashi 800, Tomita, Odai-machi, Ohira-machi, Shimotsuga-gun, Tochigi Prefecture Inside the Cooling Division, Hitachi, Ltd. 3H039 AA03 AA11 BB28 CC01 CC28 CC34 CC49

Claims (5)

[Claims] 1. A cylinder having an inner wall formed between a pair of end plates and having a planar shape formed by a continuous curve, and an outer wall provided so as to face the inner wall of the cylinder. In a displacement type fluid machine including an outer wall and a displacer forming a plurality of spaces by the end plates, a working space in which a state of being sealed only at substantially an inflection point of the curve is only at the inflection point. A displacement type fluid machine wherein the planar shapes of the cylinder and the displacer are configured such that the volume of the working space is maximized in a sealed state. 2. A cylinder having an inner wall formed by a continuous curve between end plates and an outer wall provided so as to face the inner wall of the cylinder. In a displacement type fluid machine including an outer wall and a displacer forming a plurality of spaces by the end plate, a straight line connecting the inflection points of the working space, which is in a state of being sealed only on the inflection point of the curve. A displacement type fluid machine wherein the plane shapes of the cylinder and the displacer are configured such that an orthogonal line and a normal line of an inflection point are substantially parallel to each other. 3. A cylinder having an inner wall formed between a pair of end plates and having a planar shape formed by a continuous curve, and an outer wall provided so as to face the inner wall of the cylinder. In a displacement type fluid machine including an outer wall and a displacer forming a plurality of spaces by the end plate, a volume change characteristic of a working space having a state of being sealed only at an inflection point of the curve, near the end of suction. The displacement type fluid machine wherein the planar shape of the cylinder and the displacer is configured such that a change in the volume of the working space is small. 4. A cylinder having an inner wall formed between a pair of end plates and having a planar shape formed by a continuous curve, and an outer wall provided so as to face the inner wall of the cylinder. In a displacement type fluid machine having an outer wall and a displacer forming a plurality of spaces by the end plate, a drive shaft of the displacer having a maximum working space having a state of being sealed only at an inflection point of the curve A displacement type fluid machine characterized in that a rotation angle of a drive shaft of a displacer in which a volume of a working space adjacent to the working space and sucking a working fluid is maximized is delayed with respect to a rotation angle of the displacement space. 5. A refrigeration / air-conditioning system equipped with the positive displacement fluid machine according to claim 1.