JP2001003878A - Displacement type fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement type fluid machine of high efficiency reduc ing gas leakage from a seal part in a compression stroke. SOLUTION: In a displacement type fluid machine with a displacer 5 and a cylinder 4 arranged between end plates, an outline curve of a cylinder internal wall surface or a displacer external wall surface is so formed that a radial clearance δ of a seal part formed by the cylinder internal wall surface and displacer external wall surface to seal gas in a compression stroke satisfies dδ/dκ<=0 (δ: shortest distance between the cylinder internal wall surface and displacer external wall surface and κ: the average curvature of the curvature of a cylinder outline and the curvature of a displacer outline in the seal part) at a shaft optional rotation angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a pump, a compressor,
The present invention relates to a positive displacement fluid machine usable for an expander or the like.

[0002]

2. Description of the Related Art Conventionally, as a positive displacement fluid machine, a reciprocating fluid machine in which a piston moves reciprocatingly in a cylindrical cylinder to move a working fluid, and a cylindrical piston is eccentric in a cylindrical cylinder Rotary (rolling piston type) fluid machine that moves a working fluid by rotating motion, meshing a pair of fixed scroll and orbiting scroll having a spiral wrap upright on an end plate, and orbiting the orbiting scroll. 2. Description of the Related Art A scroll type fluid machine that moves a working fluid by a hydraulic fluid is known.

[0003] Reciprocating fluid machines have the advantage that they are easy to manufacture and inexpensive because of their simple structure. Consideration is given to the reduction in performance due to the increase in pressure loss due to the high flow velocity of the process, and the need to reciprocate the piston, which increases vibration and noise unless the rotating shaft system is completely balanced. Is required.

[0004] Further, in the rotary type fluid machine, the stroke from the end of suction to the end of discharge is 360 ° of the shaft rotation angle, so that the pressure loss in the discharge process is smaller than that of the reciprocating type fluid machine, but the pressure loss is one per rotation of the shaft. Since the gas is discharged multiple times, the fluctuation of the gas compression torque is relatively large, so that consideration must be given to vibration and noise as in the case of a reciprocating fluid machine.

Further, in the scroll type fluid machine, the stroke from the end of the suction to the end of the discharge is as long as 360 ° or more in terms of the shaft rotation angle.
°), there is an advantage that pressure loss in the discharge process is small, and since a plurality of working chambers are generally formed, fluctuation of gas compression torque is small and vibration and noise are small.

However, it is necessary to manage the clearance between the spiral wraps in the lap meshing state and the clearance between the end plate and the tip of the lap, and high precision processing is required.

Further, since the stroke from the end of the suction to the end of the discharge is as long as 360 ° or more in terms of the shaft rotation angle, the time of the compression process is long, and consideration must be given to internal leakage.

By the way, the displacer (swirl piston) 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. Japanese Patent Application Laid-Open No. 55-2335 discloses a type of positive displacement fluid machine for transporting fluid.
No. 3, U.S. Pat.
Japanese Patent Application Publication No. 202869, Japanese Patent Application Laid-Open No. 6-280758, and the like.

The displacement type fluid machine proposed here is:
A plurality of members (vanes) extend radially from the center and have a petal-shaped piston, and a cylinder having a hollow portion substantially similar to the piston. It moves fluid.

The displacement type fluid machine disclosed in the above publication does not have a reciprocating portion unlike the reciprocating type, so that the rotating shaft system can be perfectly balanced. Therefore, it is essentially advantageous as a positive displacement fluid machine in that the vibration is small and the relative slip speed between the piston and the cylinder is small so that the 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 piston takes about 180 ° in terms of shaft rotation angle.
(Or 210 °), which is short (approximately half of the rotary type and equivalent to the reciprocating type). Therefore, it is necessary to consider that the flow velocity of the fluid in the discharge process increases, the pressure loss increases, and the performance decreases. Become.

In the fluid machine disclosed in the above publication,
The shaft rotation angle from the end of suction to the end of discharge of each working chamber is short, and there is a time lag (time lag) from the end of discharge of the working fluid to the start of the next (compression) stroke (end of suction). Then, from the end of suction to the end of discharge, the working chamber is formed to be biased around the drive shaft. As a result, the mechanical balance is poor, and a rotational moment acting to rotate the piston itself acts on the piston as a reaction force from the compressed working fluid, reducing the reliability due to friction and wear of the vane. Consideration is needed.

The displacement type fluid machine proposed in Japanese Patent Application Laid-Open No. 9-268987 is a displacement type fluid machine which conveys a working fluid by a swiveling motion of a displacer, as described above. The process from the end of the chamber suction to the end of the discharge is performed by rotating the shaft from approximately 270 ° to 360 °.
°, which is advantageous in that pressure loss in the discharge stroke can be reduced.

[0014]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 9-268 is disclosed.
In the fluid machine disclosed in Japanese Patent Publication No. 987, a seal portion for reducing gas leakage in a compression stroke forms a radial gap between an inner wall surface of a cylinder and an outer wall surface of a displacer as the displacer performs a revolving motion. It has a structure to do. Since the gap in the radial direction of the seal portion is constant at an arbitrary rotation angle of the shaft, it is necessary to consider that gas leakage increases when the curvature of the contour on the inner wall surface of the cylinder or the outer wall surface of the displacer is large.

An object of the present invention is to provide a positive displacement type fluid machine which reduces gas leakage from the seal portion during a compression stroke and has high efficiency.

[0016]

An object of the present invention is to dispose a displacer and a cylinder between end plates, and when the center of the displacer is aligned with the center of rotation of a rotating shaft, one surface is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. A space is formed, and in a displacement type fluid machine in which a plurality of spaces are formed when a positional relationship between the displacer and the cylinder is set at a swiveling position, the displacement is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer, In the case, the radial gap δ of the seal portion that performs gas sealing is
At an arbitrary rotation angle of the shaft, ∂δ / ≦ κ ≦ 0 (δ: the shortest distance between the inner wall surface of the cylinder and the outer wall surface of the displacer, κ: average curvature of the curvature of the cylinder contour and the curvature of the displacer contour at the seal portion). In addition, a contour curve of the inner wall surface of the cylinder or the outer wall surface of the displacer is formed.

Further, the object is to dispose a displacer and a cylinder between end plates, and when the displacer center is aligned with the rotation center of a rotating shaft, one space is formed by the cylinder inner wall surface and the displacer outer wall surface. In a displacement type fluid machine in which a plurality of spaces are formed when a positional relationship between the displacer and the cylinder is set at a swivel position, a gas seal formed by the cylinder inner wall and the displacer outer wall during a compression stroke. , So that the radial gap δ of the seal portion performing the above satisfies ∂δ / ∂κ ≧ 0 near the end of the discharge of the compression chamber gas.
This is achieved by forming a contour curve of the cylinder inner wall surface or the displacer outer wall surface.

More preferably, in the vicinity of the end of the discharge of the compression chamber gas, the residual gas in the compression chamber is 1% of the gas amount at the end of the suction.
It is as follows.

Still another object of the present invention is to dispose a displacer and a cylinder between end plates and form a space by the inner wall surface of the cylinder and the outer wall surface of the displacer when the center of the displacer is aligned with the center of rotation of a rotating shaft. In a displacement type fluid machine in which a plurality of spaces are formed when the positional relationship between the displacer and the cylinder is set to a swirling position, the displacement is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. This is achieved by forming a contour curve of the inner wall surface of the cylinder or the outer wall surface of the displacer such that the radial gap δ of the sealing portion for performing sealing satisfies ∂δ / ∂κ ≧ 0 near the start of gas compression. .

More preferably, near the start of gas compression, the differential pressure between the compression chamber and the suction chamber is 0.5 MPa or less.

Still another object of the present invention is to dispose a displacer and a cylinder between end plates and form a space by the inner wall surface of the cylinder and the outer wall surface of the displacer when the center of the displacer is aligned with the center of rotation of a rotating shaft. In a displacement type fluid machine in which a plurality of spaces are formed when the positional relationship between the displacer and the cylinder is set to a swirling position, the displacement is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. The radial gap δ of the sealing portion for performing the sealing satisfies ∂δ / ∂κ ≦ 0 at an arbitrary shaft rotation angle, and ∂δ / ∂κ ≧ 0 near the end of the discharge of the compression chamber gas. , Forming a contour curve of the cylinder inner wall surface or the displacer outer wall surface.

Still another object of the present invention is to dispose a displacer and a cylinder between end plates and form a space by the inner wall surface of the cylinder and the outer wall surface of the displacer when the center of the displacer is aligned with the center of rotation of a rotating shaft. In a displacement type fluid machine in which a plurality of spaces are formed when the positional relationship between the displacer and the cylinder is set to a swirling position, the displacement is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. The cylinder so that the radial gap δ of the sealing portion for sealing satisfies ∂δ / ∂κ ≦ 0 at an arbitrary rotation angle of the shaft, and ∂δ / ∂κ ≧ 0 near the start of the gas compression. This is achieved by forming a contour curve of the inner wall surface or the outer wall surface of the displacer.

Still another object of the present invention is to dispose a displacer and a cylinder between end plates and form a space by the inner wall surface of the cylinder and the outer wall surface of the displacer when the center of the displacer is aligned with the center of rotation of a rotating shaft. In a displacement type fluid machine in which a plurality of spaces are formed when the positional relationship between the displacer and the cylinder is set to a swirling position, the displacement is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. The radial gap δ of the sealing portion for performing sealing satisfies ∂δ / ∂κ ≦ 0 at an arbitrary shaft rotation angle, and satisfies ∂δ / ∂κ ≧ 0 near the end of the discharge of the compression chamber gas,
This is achieved by forming a contour curve of the inner wall surface of the cylinder or the outer wall surface of the displacer so as to satisfy ∂δ / ∂κ ≧ 0 near the start of the gas compression.

Still another object of the present invention is to dispose a displacer and a cylinder between end plates and form a space by the inner wall surface of the cylinder and the outer wall surface of the displacer when the center of the displacer is aligned with the center of rotation of a rotating shaft. In a displacement type fluid machine in which a plurality of spaces are formed when the positional relationship between the displacer and the cylinder is set to a swirling position, the displacement is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. The radial gap δ of the sealing portion for sealing is HC
This is achieved by forming a contour curve of the inner wall surface of the cylinder or the outer wall surface of the displacer so as to satisfy ∂δ / ∂κ ≧ 0 when using a system refrigerant.

Still another object of the present invention is to provide a rotary shaft supported by a main bearing, a displacer and a cylinder disposed between end plates, and when the displacer center is aligned with the rotation center of the rotary shaft, the inner wall surface of the cylinder and the cylinder In a positive displacement fluid machine in which one space is formed by the outer wall surface of the displacer and a plurality of spaces are formed when the positional relationship between the displacer and the cylinder is at the swiveling position, the cylinder is installed on the main bearing and the center of the cylinder is When assembling the rotating shaft and the displacer on the basis of the center of the cylinder, the gap between the seal point between the outer wall surface of the displacer and the inner wall surface of the cylinder formed when the rotating shaft is rotated by 360 ° is determined by the sealing method. At the point where the average curvature between the curvature of the cylinder contour and the curvature of the displacer contour in the section is the largest The top is small, is accomplished by.

[0026]

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

FIGS. 1 to 3 show an embodiment of a positive displacement fluid machine according to the present invention. FIG. 1 (a) is a longitudinal sectional view taken along the line AA of FIG. Area view), FIG. 1 (b)
FIG. 2A is a cross-sectional view of the compression chamber as viewed in the direction indicated by arrows BB in FIG. 2A, FIG. 2 is an operation principle diagram of the positive displacement compression element, and FIG.

In FIGS. 1A and 3, a positive displacement element 1 (hereinafter simply referred to as a compression element) is placed in a closed container 3.
And an electric element 2 for driving the same.

The compression element 1 will be described with reference to FIG.

FIG. 3 shows a triple wrap in which three sets of wraps having the same contour are combined. The inner peripheral shape of the cylinder 4 is formed such that the hollow portion has the same wrap shape every 120 ° (center O ′). Three substantially arc-shaped vanes 4b projecting inward are formed at the ends of these individual hollow portions. The displacer 5 is disposed in the cylinder 4 with its center shifted by a distance ε so that the inner peripheral wall 4a (the portion having a larger curvature than the vane 4b) of the cylinder 4 and the vane 4b engage with each other.

When the center O 'of the cylinder 4 coincides with the center O of the displacer 5, a gap having a constant width is formed between the two contours.

Next, the operation principle of the compression element 1 will be described with reference to FIGS.

The symbol O is the center of the displacer 5, and the symbol O 'is the center of the cylinder 4 and the drive shaft 6. The symbol a,
b, c, d, e, f, and g represent meshing contacts (seal points) between the inner peripheral wall 4a and the vane 4b of the cylinder 4 and the displacer 5. The inner peripheral contour shape of the cylinder 4 is smoothly connected continuously at three locations with the same combination of curves. Focusing on one of these, the curve forming the inner peripheral wall 4a and the vane 4b can be regarded as one thick vortex curve (thinking the tip of the vane 4b as the beginning of the vortex), and the inner wall curve (g -A) is a winding angle of 360 ° which is the sum of the arc angles forming the curve (the design concept is 36 degrees).
Although it is 0 °, it is not exactly 360 ° due to manufacturing errors. The same applies hereinafter. ), The outer wall curve (g-
b) is a vortex curve with a winding angle of approximately 360 °. As described above, the one inner peripheral contour shape is formed from the inner wall curve and the outer wall curve. It is arranged on these two curved circles at almost equal pitch (120 ° because it is a three-line wrap)
By connecting the outer wall curve and the inner wall curve of adjacent spiral pairs with a smooth connection curve (bb ′) such as an arc, the entire inner peripheral contour shape of the cylinder 4 is configured. The outer peripheral shape of the displacer 5 is also configured in the same principle as that of the cylinder 4.

The spiral pairs composed of three curves are arranged at substantially equal pitches (120 °) on the circumference in order to distribute the load accompanying the compressing operation evenly and to facilitate manufacture. And especially if these are not a problem,
Irregular pitch may be used.

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. Three ports are provided on the partition plate 7 or an end plate of the auxiliary bearing 8 (details will be described later). 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 displacer 5
A working chamber 9 (a space in which a suction is completed and a compression or discharge stroke is completed among a plurality of hermetically sealed spaces surrounded by a cylinder inner peripheral contour and a displacer outer peripheral contour) is formed around the center O.

If the winding angle is limited to 360 °, this space is eliminated at the end of the compression, but the suction is terminated at that moment, so this space is counted as one. One working chamber 9 surrounded by a contact a and a contact b and hatched.
(The two working chambers are separated into two at the end of the suction, but the two working chambers are connected and become one as soon as the compression stroke is started.)

FIG. 2A shows a state in which the suction of the working gas from the suction port 7a into the working chamber 9 has been completed. FIG. 2B shows a state in which the drive shaft 6 has rotated clockwise by 90 ° from this state, and FIG. 2C shows a state in which the drive shaft 6 has rotated 180 ° from the beginning. °
The rotated state is shown in FIG. From FIG. 2 (4) to 90
When it rotates, it returns to the initial state of FIG. From this, the working chamber 9 reduces its volume as the rotation progresses,
Since the discharge port 8a is closed by the discharge valve 10 (see FIG. 1), 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, ie, the start of compression, to the end of discharge is 360 °,
While the compression and discharge strokes are being performed, the next suction stroke is prepared, and the end of discharge is the start of the next compression.

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 the working chambers have respective phases. The compression is performed with a shift. That is, when focusing on one space, the rotation angle of the drive shaft 6 is 360 ° from the suction to the discharge, but in this embodiment, three working chambers are formed, and these are discharged at positions shifted by 120 °. Therefore, when the compressor is operated as a compressor that compresses a refrigerant that is a fluid, the rotation angle of the drive shaft 6 becomes 3 degrees during a rotation angle of 360 °.
Discharge the refrigerant.

Next, a displacement type fluid machine incorporating the compression element 1 having the above-described shape will be described with reference to FIGS.

In the figure, a compression element 1 is a cylinder 4
In addition to the displacer 5, a rotating shaft 6 for driving the displacer 5 by fitting a crank portion 6a to a drive bearing 5a at the center of the displacer 5, a partition plate 7 for closing both ends of the cylinder 4, and a rotating shaft 6 , A suction chamber 11 a formed by the main bearing 11 and the partition plate 7, a suction port 7 a formed in the partition plate 7, and a discharge formed in an end plate of the sub bearing 8. Port 8a,
There is a discharge valve 10 that opens and closes the discharge port 8a with a differential pressure. Reference numeral 12 denotes a discharge cover for forming the discharge chamber 8b integrally with the auxiliary bearing 8.

The electric element 2 includes a stator 2a and a rotor 2b, and the rotor 2b is fixed to the rotating shaft 6 by shrink fitting or the like. Reference numeral 13 denotes lubricating oil stored at the bottom of the closed container 3 and the lower end of the rotating shaft 6 is immersed. Reference numeral 14 denotes a suction pipe, reference numeral 15 denotes a discharge pipe, and reference numeral 9 denotes the above-described working chamber formed by engagement of the inner peripheral wall 4a and the vane 4b of the cylinder 4 with the displacer 5.

Here, an example of a method of forming the contour shapes of the displacer 5 and the cylinder 4 which are the main components of the compression element 1 will be described with reference to FIGS.

FIGS. 4A and 4B show a displacer 5 having a planar shape formed by a combination of arcs.
Is a plan view, and (b) is a side view. FIGS. 5A and 5B
FIGS. 4A and 4B are cylinders 4 which mesh with each other in pairs with the displacer 5 shown in FIG. 4, wherein FIG. 4A is a plan view and FIG. 4B is a side view. 6 is a diagram in which the center O of the displacer 5 shown in FIG. 4 and the center O ′ of the cylinder 5 shown in FIG. 5 are overlapped, and a part of the wall surface of the displacer 5 and the cylinder 4 is drawn.

In FIG. 4A, the same contour shape is continuously connected at three places around a centroid O (the center of the equilateral triangle IJK). The contour shape is formed by nine arcs from a radius R1 to a radius R9, and points p, q, r, s, t, u, v, w, x,
y is a connection point of arcs having different radii. Curve p
q is an arc of radius R1, where point p is R1 from vertex I
At a distance. The curve qr is an arc of a radius R2 having a center on an extension of a straight line connecting the contact point q and the center of the radius R1, a curve r
s is an arc of a radius R3 having a center on an extension of a straight line connecting the contact r and the center of the radius R2, and a curve st is a circular arc of the contact s and the radius R3.
Is an arc of a radius R4 having a center on a straight line connecting the centers of the circles.

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, and a curve uv.
Is an arc of 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 a curve vw is an arc of a radius R7 having a center on an extension of a straight line connecting the contact point v and the center of the radius R6. Is an arc having a radius R8 having a center on a straight line connecting the contact w and the center of the radius R7, and a curve xy represents a contact x and a radius R
8 is an arc of a radius R9 centered on a vertex J on a straight line connecting the centers of 8.

Note that the radii R1, R2, R3, R4, R
The angles of the respective arcs of 5, 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 5 is obtained, and the displacer 5 is configured by giving the thickness h.

When the planar shape of the displacer 5 is determined,
When the displacer 5 makes a revolving motion with a revolving radius ε, the contour shape of the cylinder 4 that meshes with the displacer 5 is, as shown in FIG. 6, an offset curve having a normal distance ε outside the curve constituting the contour shape of the displacer 5. Becomes

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 nine arcs like the displacer 5, 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 'has a radius (R1 +
ε) arc, where point p ′ is (R9 + ε) from vertex I
At a distance. The curve q'r 'is defined by the point q' and the radius (R1 +
radius (R) having a center on an extension of a straight line connecting the centers of ε)
2-ε), the curve r ′s ′ has a contact point r ′ and a radius (R2
-[Epsilon]), an arc having a radius (R3- [epsilon]) having a center on an extension of a straight line connecting the centers of s' and radii (R3
-Ε) with a center on a straight line connecting the centers of (R4-
ε).

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 the 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 respective 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 5. The contour shape from point p 'to point y' is defined by 1 counterclockwise around centroid O '.
When rotated by 20 °, the point p ′ coincides with the point y ′, and
When rotated by 20 °, the contour shape of the entire circumference is completed. Thereby, the planar shape of the cylinder is obtained. Cylinder thickness H
Is slightly thicker than the thickness h of the displacer 5.

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

FIG. 6 is a view showing a part of the center O of the displacer 5 and the center O 'of the cylinder 4 overlapped with each other. The gap formed between the displacer 5 and the cylinder 4 is set to have a distance ε equal to the turning radius. Therefore, when the displacer 5 turns with the turning radius ε, under ideal conditions with no processing error or the like, the seal point formed between the outer wall surface of the displacer and the inner wall surface of the cylinder is in a contact state (a state with no gap). . However, in practice, it is necessary to set the gap δ shown in FIG. 7 between the outer wall surface of the displacer and the inner wall surface of the cylinder in consideration of the processing error of the displacer 5 and the cylinder 4 and the eccentricity of the rotating shaft in the bearing. . Hereinafter, this gap δ is defined as the shortest distance between the outer wall surface of the displacer and the inner wall surface of the cylinder.

In FIG. 7, 17 is a compression chamber, 18 is a suction chamber, 4 is a cylinder, 5 is a displacer, 19 is a seal part, and 20 is a radial gap δ of the seal part. The figure shows
Displacer outer wall surface 5 formed when displacer 5 turns with turning radius ε-δ (no processing error or the like)
3 shows a gas seal portion 19 between the cylinder b and the cylinder inner wall surface 4a. The gas in the compression chamber 17 flows in the direction of the solid line arrow and leaks into the suction chamber 18, and the smaller the gap δ is, the more the gas leakage can be reduced.

Setting the gap δ constant at an arbitrary shaft rotation angle is realized by setting the turning radius of the displacer 5 to ε−δ (unless the eccentricity of the rotation shaft 6 by the bearings 8 and 11 is considered). Is done. However, as shown in FIG. 8, the amount of gas leaking from the seal portion 19 is such that the larger the average curvature of the curves constituting the contours of the outer wall surface 5b of the displacer and the inner wall surface 4a of the cylinder, the larger the gas in the seal portion 19 becomes. The amount of leakage increases.

Therefore, in order to reduce the amount of gas leakage in the seal portion 19 having a large curvature, as shown in FIG.
As the curvature of the seal portion 19 in the seal portion 19 increases, the gap δ between the seal portions 19 needs to be reduced.

That is, the gap δ and the curvature κ (hereinafter, the curvature κ
Is the curvature of the outer wall surface 5b of the displacer and the inner wall surface 4 of the cylinder.
∂δ / ∂κ ≦ between the curvature of a and the average curvature)
The relationship of 0 must be satisfied at any axis rotation angle.

A method for realizing the contour curve of the displacer outer wall surface 5b or the cylinder inner wall surface 4a that satisfies the relational expression will be described below.

The method for realizing the above-mentioned contour curve is as follows.
The contours of the outer wall surface of the displacer and the inner wall surface of the cylinder are obtained by the method shown in FIG. Next, as shown in FIGS. 10A and 10B, the contour curve of the outer wall surface 5b of the displacer or the inner wall surface 4a of the cylinder is corrected so that the seal gap δ becomes narrower at the point where the curvature κ at the seal portion becomes larger. FIG. 10A shows a method of reducing the seal gap δ by deforming the contour curve of the displacer outer wall surface 5b toward the cylinder inner wall surface as indicated by a dotted line 21.
FIG. 10B shows a method of reducing the seal gap δ by deforming the contour curve of the cylinder inner wall surface 4a in the direction of the displacer outer wall surface 5b as indicated by a dotted line 21. In addition to these methods, where the curvature κ of the seal portion 19 is large, the contour curve of the outer wall surface of the displacer is deformed in a direction away from the inner wall surface of the cylinder to increase the gap δ of the seal portion. There is a method of expanding the gap δ of the seal portion by deforming in a direction away from the outer wall surface of the displacer.

However, the range in which the above-described correction is performed is limited to a range in which no trouble occurs when the displacer 5 makes a turning motion.

The method of setting the seal gap δ that satisfies the relationship of ∂δ / 示 し κ ≦ 0 shown in FIG. 9 is the most ideal method, but the design is based on the contour of the outer wall surface of the displacer and the inner wall surface of the cylinder. Seal gap δ where the average curvature is large
Is not small, the seal gap δ becomes ∂δ / ∂κ ≦ 0
There is a case where the performance is not significantly affected even if the relationship is not satisfied. Therefore, three methods for realizing the contour of the outer wall surface of the displacer and the contour of the inner wall surface of the piston to keep the gas leakage amount of the seal portion 19 within a practical allowable range will be described below.

First, the first method will be described.

FIG. 11 shows the relationship between the volume of the compression chamber and the fluid pressure in the compression chamber. The compression stroke is performed according to the direction of the solid arrow. V2 in the figure is the maximum volume of the compression chamber at the start of gas compression, and V1 is the residual volume of the compression chamber near the end of gas discharge (V1 is 1% or less of V2). Near the end of gas discharge (volume V1 of compression chamber)
In this case, since the residual gas amount is small, there are cases where the sealing performance in the vicinity is not so important in practical use. Therefore, near the end of gas discharge, even if the seal gap δ that satisfies the relationship of ∂δ / ∂κ ≧ 0 is set (that is, the seal gap δ is widened even when the seal curvature κ is large), it is practically sufficient. The performance of a positive displacement fluid machine can be realized.

A method for realizing the contour curve of the displacer outer wall surface 5b or the cylinder inner wall surface 4a that satisfies the above relational expression will be described below.

The method for realizing the above-mentioned contour curve is as follows.
The contours of the outer wall surface of the displacer and the inner wall surface of the cylinder are obtained by the method shown in FIG. Next, in contrast to the method shown in FIGS. 10 (a) and 10 (b), the contour curve of the outer wall surface 5b of the displacer or the inner wall surface 4a of the cylinder is changed by the seal portion 19 near the end of the discharge to {δ / ∂ Correct so that κ ≧ 0. However, the range in which these corrections are performed is limited to a range in which no trouble occurs when the displacer 5 makes a turning motion.

Next, the second method will be described.

Generally, the amount of fluid flowing through a narrow gap such as a seal portion of a positive displacement fluid machine is, as shown in FIG.
It increases as the pressure difference δp between the compression chamber pressure and the suction chamber pressure (that is, the high pressure section and the low pressure section at both ends of the seal section) increases.
Conversely, near the start of gas compression (the pressure difference between the suction chamber 18 and the compression chamber 17 is 0.5 MPa or less), since the pressure difference δp is small, the gas leakage amount is small even if the curvature κ in the seal portion 19 is large. Can be maintained. Thus, near the start of gas compression, the seal gap δ that satisfies the relationship ∂δ / ∂κ ≧ 0
(That is, the gap δ of the seal portion is increased even if the curvature κ of the seal portion is increased), it is possible to realize practically sufficient performance of the positive displacement fluid machine.

A method of realizing the contour curve of the outer wall surface of the displacer or the inner wall surface of the cylinder satisfying the above relational expression will be described below.

The method for realizing the above-mentioned contour curve is as follows.
The contours of the outer wall surface of the displacer and the inner wall surface of the cylinder are obtained by the method shown in FIG. Next, in contrast to the method shown in FIGS. 10 (a) and 10 (b), the contour curve of the outer wall surface of the displacer or the inner wall surface of the cylinder is changed to ∂δ / ∂κ ≧ 0
Modify so that However, the range in which these corrections are made is limited to a range in which no trouble occurs when the displacer makes a turning movement.

Using the above two methods for realizing the gap δ between the seal portions, the method for realizing the ideal gap δ shown in FIG. 9 (between the gap δ and the curvature κ, ∂δ / ∂κ ≦ 0) FIG. 13 shows an example in which the relationship is corrected at an arbitrary axis rotation angle.

FIG. 13 is a graph showing the progress of the gas compression (of the outer wall surface 5b of the displacer and the inner wall surface 4a of the cylinder).
This shows changes in the curvature κ of the seal portion and the seal gap δ. The solid arrows indicate the direction in which the gas compression process proceeds. In this embodiment, the curvature gradually decreases from the start of compression, and slightly before the end of gas discharge (compression chamber volume V1 in FIG. 11).
The curvature becomes minimum, and thereafter the curvature starts to increase. With respect to the change in the curvature κ, the section 2-3 represents an ideal curve of the seal gap δ (a contour that satisfies the condition of ∂δ / ∂κ ≦ 0), and the section 1-2 is near the start of compression (the suction chamber and the compression chamber). Seal gap δ (contour that satisfies the condition of ∂δ / ∂κ ≧ 0) when the pressure difference with the chamber is 0.5 MPa or less), section 3-
Reference numeral 4 denotes a corrected seal gap δ (contour that satisfies the condition of ∂δ / ∂κ ≧ 0) near the end of discharge (residual compression chamber volume V1: 1% or less of V2). For this embodiment, section 1
It is of course possible to use either one of -2 or section 3-4.

Next, the third method will be described.

When an HC-based refrigerant is used as the compressed gas, the pressure difference between the compression chamber 18 and the suction chamber 17 is small. In such a case, since the influence of the curvature κ has little effect on the leakage of the compressed gas, the seal gap δ that satisfies the relationship of ∂δ / ∂κ ≧ 0
(I.e., even if the curvature κ of the seal part is increased, the gap δ of the seal part is widened), the practically sufficient performance of the positive displacement fluid machine can be realized.

In the state where the positive displacement fluid machine is assembled, the gap at the seal point between the outer wall surface 5b of the displacer and the inner wall surface 4a of the cylinder can be measured as follows.

First, the cylinder 4 is installed on the fixed main bearing 6 to determine the cylinder center O ′, and the cylinder center O ′ is determined.
Assembling the rotating shaft 6 and the displacer 5 on the basis of the above, and measuring the gap at the seal point between the displacer outer wall surface 5b and the cylinder inner wall surface 4a formed by rotating the rotating shaft 6 by 360 ° using a gap gauge or the like. Thus, a gap between the seal portions 19 is obtained. Therefore, by making the gap measured at the place where the curvature of the seal portion 19 is the largest, it is possible to realize a positive displacement fluid machine with a small amount of compressed gas leakage.

[0077]

As described above in detail, according to the present invention, the radial gap δ of the seal portion formed by the inner wall surface of the cylinder and the outer wall surface of the displacer is optimized for the curvature κ of the seal at each rotational angle of the shaft. , It is possible to reduce the amount of gas leakage from the seal portion,
A highly efficient positive displacement fluid machine can be obtained.

[Brief description of the drawings]

FIG. 1 is an embodiment of a positive displacement fluid machine according to the present invention,
(A) is a vertical sectional view of a main part of the positive displacement fluid machine (A-
(B) is a cross-sectional view of the compression chamber as viewed in the direction of arrows BB in (a).

FIG. 2 is an operation principle diagram of the positive displacement fluid machine of the embodiment of FIG. 1;

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 of a displacer of the positive displacement fluid machine according to the present invention.

FIG. 5 is a diagram showing a contour configuration method 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 a view showing a gas seal portion formed between the outer wall surface of the displacer and the inner wall surface of the cylinder formed when the displacer of the positive displacement fluid machine according to the present invention turns with a turning radius of ε-δ.

FIG. 8 is a diagram showing a relationship between a radius of curvature κ and a gas leakage amount in a seal portion of the positive displacement fluid machine according to the present invention.

FIG. 9 is a diagram showing an ideal relationship between a radius of curvature κ and a seal gap δ in a seal portion of the positive displacement fluid machine according to the present invention.

FIG. 10 shows the relationship between the radius of curvature κ of the seal portion and the gap δ of the seal portion of the positive displacement fluid machine according to the present invention, where Δδ / ∂κ ≦
It is a figure showing a realization method of a contour curve of a displacer outer wall surface or a cylinder inner wall surface which satisfies 0.

FIG. 11 is a diagram showing a relationship between a compression chamber volume V and a fluid pressure p in the compression chamber of the positive displacement fluid machine according to the present invention.

FIG. 12 is a diagram showing a relationship between a pressure difference δp between a compression chamber pressure and a suction chamber pressure of a seal portion of a positive displacement fluid machine according to the present invention and a gas leakage amount.

FIG. 13 is a diagram of an embodiment in which a correction is made in a relation of ∂δ / ∂κ ≦ 0 between a gap δ of a seal portion and a curvature κ of the positive displacement fluid machine according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Displacement type compression element 2 ... Electric element 2a ... Stator 2b ... Rotor 3 ... Sealed container 4 ... Cylinder 4a ... Cylinder inner wall surface 4b ... Vane 5 ... Displacer 5b ... Displacer outer wall surface 5a ... Bearing 6 ... Rotating shaft 6a ... Crank part 7 ... Partition plate 7a ... Suction port 8 ... Sub bearing 8a ... Discharge port 8b ... Discharge chamber 9 ... Working chamber 10 ... Discharge valve 11 ... Main bearing 11a ... Suction chamber 12 ... Discharge cover 13 ... Lubricant, 14 ... Suction Pipe 15 ... Discharge pipe 16 ... Discharge passage 17 ... Compression chamber 18 ... Suction chamber 19 ... Seal part 20 ... Seal part gap δ 21 ... Corrected contour

Continuing from the front page (72) Inventor Hirokatsu Kasokabe 502, Kunitachi-cho, Tsuchiura-shi, Ibaraki Pref.Mechanical Research Laboratories, Hitachi, Ltd. F-term (Ref.) 3H039 AA03 AA04 AA11 BB15 CC02 CC29

Claims (10)

[Claims] 1. A displacer and a cylinder are arranged between end plates, and when the center of the displacer is aligned with the center of rotation of a rotating shaft, one space is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. In a displacement type fluid machine in which a plurality of spaces are formed when a positional relationship with the cylinder is set at a swirling position, a seal portion formed by the cylinder inner wall surface and the displacer outer wall surface and performing a gas seal during a compression stroke Radial gap δ at an arbitrary shaft rotation angle,
∂δ / ∂κ ≦ 0, where δ: the shortest distance between the cylinder inner wall surface and the displacer outer wall surface κ: the cylinder inner wall surface or the displacer so as to satisfy the average curvature of the cylinder contour curvature and the displacer contour curvature at the seal portion. A positive displacement fluid machine that forms the contour curve of the outer wall. 2. A displacer and a cylinder are arranged between end plates, and when the displacer center is aligned with a rotation center of a rotating shaft, one space is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. In a displacement type fluid machine in which a plurality of spaces are formed when a positional relationship with the cylinder is set at a swirling position, a seal portion formed by the cylinder inner wall surface and the displacer outer wall surface and performing a gas seal during a compression stroke Is approximately the end of the discharge of the compression chamber gas, ∂δ / ∂κ ≧ 0, where δ: the shortest distance between the inner wall surface of the cylinder and the outer wall surface of the displacer κ: the curvature of the cylinder contour at the seal and the displacer contour A ring on the inner wall surface of the cylinder or the outer wall surface of the displacer so as to satisfy the average curvature of curvature Displacement type fluid machine that applies a curve. 3. The displacement type fluid machine according to claim 2, wherein the residual gas in the compression chamber is 1% or less of the gas amount at the end of the suction near the end of the discharge of the compression chamber gas. 4. A displacer and a cylinder are disposed between end plates, and when the center of the displacer is aligned with the center of rotation of a rotating shaft, one space is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. In a displacement type fluid machine in which a plurality of spaces are formed when a positional relationship with the cylinder is set at a swirling position, a seal portion formed by the cylinder inner wall surface and the displacer outer wall surface and performing a gas seal during a compression stroke. Δ / ∂κ ≧ 0 where δ is the shortest distance between the inner wall surface of the cylinder and the outer wall surface of the displacer κ is the average curvature of the curvature of the cylinder contour and the curvature of the displacer contour at the seal portion The contour curve of the cylinder inner wall surface or the displacer outer wall surface is formed so as to satisfy Volumetric fluid machinery. 5. The displacement type fluid machine according to claim 4, wherein a differential pressure between the compression chamber and the suction chamber is 0.5 MPa or less near the start of gas compression. 6. A displacer and a cylinder are arranged between end plates, and when the center of the displacer is aligned with the center of rotation of a rotating shaft, one space is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. In a displacement type fluid machine in which a plurality of spaces are formed when a positional relationship with the cylinder is set at a swirling position, a seal portion formed by the cylinder inner wall surface and the displacer outer wall surface and performing a gas seal during a compression stroke Radial gap δ at an arbitrary shaft rotation angle,
∂δ / ∂κ ≦ 0, and near the end of the discharge of the compression chamber gas, ∂δ / ∂κ ≧ 0, where δ: the shortest distance between the inner wall surface of the cylinder and the outer wall surface of the displacer κ: curvature of the cylinder contour at the seal portion And a contour curve of the inner wall surface of the cylinder or the outer wall surface of the displacer so as to satisfy an average curvature of curvature of the contour of the displacer. 7. A displacer and a cylinder are disposed between end plates, and when the center of the displacer is aligned with the center of rotation of a rotating shaft, one space is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer, and the displacer and the cylinder are disposed. In a displacement type fluid machine in which a plurality of spaces are formed when a positional relationship with the cylinder is set at a swirling position, a seal portion formed by the cylinder inner wall surface and the displacer outer wall surface and performing a gas seal during a compression stroke Radial gap δ at an arbitrary shaft rotation angle,
∂δ / ∂κ ≦ 0, and near the start of the gas compression, ∂δ / た だ し κ ≧ 0, where δ: the shortest distance between the inner wall surface of the cylinder and the outer wall surface of the displacer κ: the curvature of the cylinder contour at the seal and the displacer contour A positive displacement fluid machine that forms a contour curve of the inner wall surface of the cylinder or the outer wall surface of the displacer so as to satisfy an average curvature of the following curvatures. 8. A displacer and a cylinder are arranged between end plates, and when the center of the displacer is aligned with the center of rotation of a rotating shaft, one space is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. In a displacement type fluid machine in which a plurality of spaces are formed when a positional relationship with the cylinder is set at a swirling position, a seal portion formed by the inner wall surface of the cylinder and the outer wall surface of the displacer and performing a gas seal during a compression stroke. Radial gap δ, at any axis rotation angle,
∂δ / ∂κ ≦ 0, near the end of discharge of the compression chamber gas, を δ / ∂κ ≧ 0, and near the start of gas compression, ∂δ / ∂κ ≧ 0, where δ: cylinder inner wall surface And a shortest distance between the outer wall surface of the cylinder and the displacer. Κ: a positive displacement fluid machine that forms a contour curve of the inner wall surface of the cylinder or the outer wall surface of the displacer so as to satisfy the curvature of the cylinder contour and the average curvature of the displacer contour at the seal portion. 9. A displacer and a cylinder are arranged between end plates, and when the center of the displacer is aligned with the center of rotation of a rotating shaft, one space is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer. In a displacement type fluid machine in which a plurality of spaces are formed when a positional relationship with the cylinder is set at a swirling position, a seal portion formed by the cylinder inner wall surface and the displacer outer wall surface and performing a gas seal during a compression stroke When the HC-based refrigerant is used, the radial gap δ is δ / ∂κ ≧ 0, where δ is the shortest distance between the inner wall surface of the cylinder and the outer wall surface of the displacer. Κ is the curvature of the cylinder contour at the seal and the displacer contour. The contour of the inner wall surface of the cylinder or the outer wall surface of the displacer is set so as to satisfy the average curvature of curvature. Displacement type fluid machine for forming a line. 10. A rotating shaft is supported by a bearing, and a displacer and a cylinder are arranged between end plates. When the center of the displacer is aligned with the center of rotation of the rotating shaft, one of the inner wall surface of the cylinder and the outer wall surface of the displacer forms one. A space is formed, and in a displacement type fluid machine in which a plurality of spaces are formed when the positional relationship between the displacer and the cylinder is set at a turning position, a cylinder is installed on the bearing to determine a cylinder center,
When assembling the rotating shaft and the displacer on the basis of the cylinder center, the gap between the outer wall surface of the displacer and the inner wall surface of the cylinder, which is formed when the rotating shaft is rotated by 360 °, is defined as the cylinder contour in the seal portion. The displacement type fluid machine having the smallest gap at the point where the average curvature of the curvature of the displacer contour and the curvature of the displacer contour is largest.