JPH0735068A - Fluid compressor - Google Patents

Abstract

PURPOSE:To reduce pressure loss by setting the spiral pitch form of a blade groove so that a specific capacity ratio formula is met by the number of turns of the blade, the capacities of compression chambers, and capacities of groove bottom spaces. CONSTITUTION:The spiral pitch form of a blade groove 13 is set so that the capacity ratio formula (V1+Va)/(Vn-1+Vb)=3 thru 12 is met, where (n) is the number of turns of a blade 14, V1 is compression chamber capacity of the suction side first chamber, Va is the groove bottom space capacity of the first turn of blade in communication with the same compression chamber, Vn-1 is the compression chamber capacity of the discharge side final chamber, and Vb is the groove bottom space capacity of the prior-to-final turn in communication with the discharge side final chamber. Thereby the range of compression chamber capacity ratio to the number of turns of the blade, or the range of the pressure ratio, can be set appropriately, which allows preventing counterflow of the discharge gas with no risk of out of attainment of the pressure rise, reducing pressure loss, and enhancing the compressing performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid compressor used for, for example, a refrigerating cycle apparatus and for compressing a refrigerant gas.

[0002]

2. Description of the Related Art Reciprocating compressors and rotary compressors are known as compressors for compressing a refrigerant in, for example, a refrigeration cycle apparatus. However, this kind of structure is extremely complicated and has a problem that the number of parts is large.

Therefore, recently, as a relatively simple structure,
In addition, there has been proposed a fluid compressor that improves the sealability and enables efficient compression, and that facilitates the manufacture and assembly of parts.

In this structure, a rotating body is arranged in a cylinder, the shaft portions of which are eccentric to the cylinder and rotatably supported, and a spiral groove is provided on the peripheral surface of the rotating body, and a blade is provided therein. It is configured to be wound up and down freely, to rotate a cylinder and a rotating body, to take in a refrigerant gas into a compression chamber which is a space chamber formed by the cylinder, the rotating body and a blade, and to compress while transferring.

[0005]

The compression chamber in this type of compressor will be described below. As shown in FIG.
The space between the two windings of the blade 14 wound around the blade groove 13 and the cylinder 2 and the piston 10, which is the rotating body, corresponds to the compression chamber V.

Further, the volume ratio and the compression ratio between the suction side and the discharge side are set with the space volume as one compression chamber volume. However, as shown in FIG. 3, the blade 1
There is a difference in the pressure applied to the blade from the adjacent compression chambers at the boundary of 4. The pressure in the left compression chamber (discharge side) of the blade in the figure is P _m , and the pressure in the right compression chamber (suction side) is P _n
Then, there is a relation of P _m > P _n .

Originally, the width dimension of the blade 14 is formed slightly smaller than the width dimension of the blade groove 13, and the blade moves so as to be capable of projecting and retracting with respect to the groove. It is pushed to the side, and this side surface contacts the blade groove side surface.

Therefore, a gap is formed between the side surface on the high pressure side and the side surface of the blade groove, which are opposite surfaces, and the compression chamber on the high pressure side,
The space between the bottom surface of the blade and the bottom of the blade groove communicates with each other.

Lubricating oil is introduced into the space chamber to apply back pressure to the blade 14, and the gas in the compression chamber V is mixed therein through the gap. Therefore, the substantial compression chamber capacity is different from that described above, and as a result, both the volume ratio and the compression ratio are different from the designed values.

To explain further, in general, the equation P _m / P _n = (V _n / V _m ) ⁿ holds. P _m, P _n: compression chamber respective pressure adjacent, V _m, V _n: the compression chambers each volume adjacent,
ⁿ : polytropic index.

For example, when the number of turns n of the blade is 5, four compression chambers are formed here. Suction side first
The chamber compression chamber is formed between the first and second rolls of the blade, and its volume is V ₁₂ . The compression chamber of the final chamber is the blade
It is formed between the fifth roll and the fifth roll, and its volume is V ₄₅ . Substituting P _m into the suction pressure Ps and P _n into the discharge pressure Pd in the above equation yields a design discharge pressure value of Pd = (V ₁₂ / V ₄₅ ) ⁿ · Ps.

However, in actuality, as described above, the compression chamber on the high pressure side and the space chamber formed by the blade bottom surface and the blade groove bottom communicate with each other. The groove bottom space volume of the first roll of the blade communicating with the first chamber compression chamber is v ₁ . Assuming that the groove bottom space volume of the fourth roll, which is the final front roll of the blade communicating with the final compression chamber, is v ₄ , the actual discharge pressure P ₃ is P ₃ = {(V ₁₂ + v ₁ ) / (V ₄₅ + v ₄ )}
ⁿ · Ps. Therefore, as shown in FIG. 5, although the normal discharge pressure Pd is calculated in design, only the discharge pressure P ₃ which is lower than that is actually obtained.

As a result, the pressure rise has not reached, backflow of the discharge gas has occurred, and pressure loss has occurred. If this compressor is used in a refrigeration cycle device, optimum cycle matching cannot be achieved, resulting in the adverse effect of performance degradation.

The present invention has been made in view of the above circumstances, and an object thereof is to set a volume ratio and a pressure ratio in consideration of a bottom space of a blade groove communicating with a compression chamber, so as to achieve a pressure loss. The object is to provide a fluid compressor capable of reducing the above-mentioned problem and improving the compression performance.

[0015]

In order to achieve the above object, a fluid compressor according to a first aspect of the present invention holds both end portions of a cylinder and rotatably supports the cylinder, and a suction portion and a discharge portion are provided in the cylinder. , The both end shafts of the rotating body are eccentrically and rotatably pivotally supported on the cylinder so that a part of the rotating body is brought into contact with the inner peripheral wall of the rotating body. Providing a spiral blade groove that gradually becomes smaller,
The blade is wound around the blade groove so as to be able to project and retract, and the cylinder and the rotating body are synchronously rotated by the rotational force transmission mechanism, and the fluid to be compressed is introduced from the suction portion, and the cylinder, the rotating body, and each blade It is taken into the compression chamber, which is a space chamber formed by, and sequentially transferred in the direction of the discharge part, and compressed as the volume of the compression chamber is reduced, and discharged from the discharge part when compressed to a predetermined pressure, the number of blade turns: n, Volume of compression chamber of suction-side first chamber: V ₁ , blade 1 communicating with this compression chamber
When the groove bottom space volume of the winding: v _a , the compression chamber volume of the discharge-side final chamber: V _n−1 , and the groove bottom space volume of the last winding before the blade communicating with this compression chamber: v _b , (V _{1 + v a) / (V} n-1 + v b) = 3~12 of such volume ratio equation is satisfied, sets the helical pitch shape of the blade groove.

The fluid compressor according to the second aspect of the invention has the same structure as the first aspect of the invention, and the number of blade turns is n, the pressure of the suction side first chamber is the pressure of the compression chamber: P ₁ , and the fluid compression chamber communicates with this compression chamber. Blade 1
When the groove bottom space pressure of the winding is p _a , the compression chamber pressure of the discharge-side final chamber is P _n-1 , and the groove bottom space pressure of the last winding before the blade communicating with this compression chamber is p _b , (P The spiral pitch shape of the blade groove was set so that the pressure ratio formula of ( _n-1 + p _b ) / (P ₁ + p _a ) = 3 to 12 was established.

[0017]

[Action] In the first _{invention, (V 1 + v a)} / (V
to _{n-1 + v b) =} 3~12 volume ratio range, setting the helical pitch shape of the blade groove. In the second invention,
_{(P n-1 + p b} ) / (P 1 + p a) = 3~12
The spiral pitch shape of the blade groove was set within the pressure ratio range of. Therefore, it is a capacity ratio that is adapted to the actual compression state and also contains the capacity of the compressed fluid flowing in the blade groove,
The compression ratio results in no pressure loss.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a fluid compressor used in, for example, a refrigeration cycle apparatus, in which a cylinder 2 is housed in a closed case 1. An annular rotor 3 is fitted on the outer peripheral wall of the central portion of the cylinder 2 in the axial direction.

A stator 4 is provided at a position corresponding to the outer peripheral surface of the rotor 3 with a narrow gap.
The stator 4 is concentrically located outside the rotor 3, is formed into an annular shape, and is fitted to the inner peripheral wall of the closed case 1.

An electric motor section 5 is formed from the rotor 3 and the stator 4 as described above, and the cylinder 2 is driven to rotate. The openings at both ends of the cylinder 2 are closed by the main bearing 6 and the sub bearing 7 while maintaining airtightness, and are rotatably supported by the respective bearings. The main bearing 6 is provided with a suction hole 8 and the auxiliary bearing 7 is provided with a discharge hole 9.

Further, inside the cylinder 2, there is arranged a piston 10 as a rotating body, which has a shaft center parallel to the center of rotation of the cylinder and eccentric by a predetermined dimension d. Due to the eccentricity setting, a part of the outer peripheral wall of the piston 10 along the axial direction is in close contact with the inner peripheral wall of the cylinder 2.

At both ends of the piston 10, a first shaft portion 10a having a long axial length and a second shaft portion 10b having a short axial length are integrally provided, each of which is a main body. The bearing 6 and the sub bearing 7 are rotatably supported in pivot holes 11 and 12 provided in the sub bearing 7.

On the circumferential surface of the piston 10, one end which is one end
From the shaft portion 10a side to the second shaft portion 10b side which is the other end,
As will be described later, spiral blade grooves 13 having a gradually decreasing pitch are formed.

The cross section of the blade groove 13 itself is substantially rectangular, and the spiral blade 14 having the same cross section.
However, it is fitted in the groove so that it can be projected and retracted. A constant hydraulic pressure is always supplied to the blade groove 13, and the blade 14 is urged in the protruding direction in response to the hydraulic pressure. Therefore, the inner peripheral edge portion of the blade 14 is in the blade groove 13, and the outer peripheral surface is in sliding contact with the inner peripheral wall of the cylinder 2.

Since the outer peripheral wall of the piston 10 is in contact with a part of the inner peripheral wall of the cylinder 2 along the axial direction and the outer peripheral surface of the spiral blade 14 is in contact with the inner peripheral wall of the cylinder 2, a space chamber is formed between these members in the cylinder. A plurality of compression chambers V are formed. The capacity of each compression chamber V is formed so as to gradually decrease from the setting of the pitch of the blade grooves 13 to the side of the suction hole 8 to the side of the discharge hole 9.

A drive pin 15 projecting inward is provided at a suction side portion of the cylinder 2, and an engagement hole 16 is provided at a peripheral surface portion of the piston 10 facing the drive pin. A rotational force transmission mechanism 17 is formed by the drive pin 15 and the engagement hole 16, and the rotational drive force of the cylinder 2 is transmitted to the piston 10 to perform rotational drive in synchronization with each other.

On the other hand, the pivot hole 11 of the main bearing 6 is provided with an oil supply pipe line 18 which opens to a space between the end face of the first shaft portion 10a and the inner peripheral wall of the closed case 1. The opening at the lower end of the oil supply conduit 18 is immersed in the lubricating oil in the oil sump 19 formed in the inner bottom of the closed case 1.

On the end face of the first shaft portion 10a of the piston 10,
An open end of the oil supply passage 20 formed of a small hole is provided, and communicates with a space portion between the end surface of the coaxial portion and the inner peripheral wall of the closed case 2. The oil supply passage 20 extends along the axial direction of the piston 10, is bent at a substantially central portion, and communicates with the bottom surface of the blade groove 13.

The sub bearing 7 is supported by the centering mechanism 21. The centering mechanism 21 engages a pin 22 projecting from the end surface of the sub bearing 7 with the pin so that the position of the pin 22 can be adjusted in the X direction, and is itself formed in a convex shape on the sub bearing end surface side. It is composed of a leaf spring 23 and a holder 24 that engages with the end of the leaf spring in the Y direction.

From the shape of the leaf spring 23, the auxiliary bearing 7 pivotally supporting the cylinder 2 and the end of the piston 10 is pressed and held along the axial direction, and the pin 22 locking structure and the leaf spring 23 holder are provided. Due to the hooking structure with respect to 24, the auxiliary bearing 7 can be aligned and supported in the XY directions.

A suction pipe 25 is connected to the suction hole 8 and communicates with an evaporator (not shown) constituting the refrigeration cycle apparatus. Furthermore, on the suction pipe 25 connection side,
A discharge pipe 26 is connected and communicates with a condenser (not shown) that also constitutes the refrigeration cycle apparatus.

By energizing the electric motor section 5, the cylinder 2 is rotationally driven, and the rotational force transmission mechanism 17
The piston 10 rotates synchronously via the. At this time,
Since the cylinder 2 and the piston 10 are pivotally supported while their rotation centers are eccentric, the blades 14 project at the portions where the intervals are open to form a plurality of compression chambers V which are space chambers.

The volume of these compression chambers V changes according to the spiral pitch of the blade grooves 13 and the blades 14, and the volume gradually decreases from the suction hole 8 side toward the discharge hole 9.

When the cylinder 2 and the piston 10 are rotationally driven, the refrigerant gas is sucked into the suction hole 8 from the evaporator through the suction pipe 25. Further, the compression chamber V is compressed and transferred as the volume thereof is continuously reduced while moving in the axial direction.

The gas compressed to a predetermined pressure in the final compression chamber V is discharged from the discharge hole 9 into the closed case 1. After filling up here, it is led out to the external condenser via the discharge pipe 26.

From the place where the high-pressure gas is filled in the closed case 1, the surface of the lubricating oil in the oil sump 19 is pushed,
Lubricating oil is sucked up into the oil supply line 18. This lubricant is
The space between the end face of the first shaft portion 10a in the pivot hole 11 of the main bearing 6 and the sealed case 1 is filled with the oil supply passage 2
Guided along 0.

Finally, the back pressure is applied to the blade 14 by being guided to the blade groove 13. The blade 14 smoothly performs a projecting and retracting operation with respect to the blade groove 13, and its outer peripheral surface surely comes into sliding contact with the inner peripheral surface of the cylinder 2.

As described above, the blade 14
The width of the blade is formed slightly smaller than the width of the blade groove 13, and the blade moves so as to project and retract with respect to the groove. However, due to the pressure difference between the compression chambers V on both sides of the blade, Pushed to the low pressure side, this side surface contacts the blade groove side surface.

Therefore, a gap is formed between the side surface on the high pressure side, which is the opposite surface of the blade 14, and the side surface of the blade groove 13, so that the compression chamber on the high pressure side communicates with the space chamber formed by the blade bottom surface and the blade groove bottom. Will be done.

Lubricating oil is introduced into the space chamber to apply back pressure to the blade 14, and the gas in the compression chamber V is mixed therein through the gap. Therefore, the substantial compression chamber capacity is different from that described above, and both the volume ratio and the compression ratio are different from the designed values.

Therefore, as will be described later, the piston 1
The spiral pitch shape of the blade groove 13 provided at 0 and the blade 14 that is fitted in the blade groove 13 so that the blade groove 13 can be inserted and retracted is set.
The number of windings of the blade 14 is n, the compression chamber volume of the suction-side first chamber is V ₁ , the blade groove space volume communicating with this compression chamber is v _a , the compression chamber volume of the discharge-side final chamber is V _n-1 , in this case the compression chamber and communicating with the blade groove chamber volume was _{v b, (V 1 + v} a) / (V n-1 + v b) = 3~12 of such volume ratio equation is satisfied, the blade groove 13 spiral pitch shapes are set.

In the above embodiment, since the number of turns n of the blade 14 is set to 5, four compression chambers are formed here. The first chamber of the suction side is the first chamber and the second chamber of the blade is
This volume is V ₁₂ because it is formed between the winding and the winding. The groove bottom space volume of the first roll of the blade communicating with the first chamber compression chamber is v ₁ . Since the compression chamber of the final chamber is formed between the fourth and fifth rolls of the blade, this volume is set to V ₄₅ . The groove bottom space volume of the fourth roll, which is the final front roll of the blade communicating with the final compression chamber, is v ₄ .

In this state, the spiral pitch shape of the blade groove may be set so that the volume ratio falls within the range of (V ₁₂ + v ₁ ) / (V ₄₅ + v ₄ ) = 3 to 12.

Since v ₁ and v ₄ are substantially equal to each other, the volume ratio becomes small, the pressure rise does not reach the level shown in FIG. 5, and there is no pressure loss. This facilitates the reduction of input and improves the compression performance.

From the pressure ratio, the number of turns of the blade is n,
The pressure of the compression chamber of the suction-side first chamber is P ₁ , the pressure of the groove space of the first winding of the blade communicating with this compression chamber is p _a , the pressure of the compression chamber of the discharge-side final chamber is P _n-1 , and this compression chamber When the groove space pressure of the fourth roll, which is the final front roll of the blade in communication, is p _b , it should be within the range of (P _n-1 + p _b ) / (P ₁ + p _a ) = 3 to 12. Then, the spiral pitch shape of the blade groove 13 is set.

In the above embodiment, since the number of turns n of the blade 14 is set to 5, four compression chambers are formed here. The first chamber of the suction side is the first chamber and the second chamber of the blade is
This pressure is P ₁₂ because it is formed between the winding and the winding. The groove bottom space pressure of the first roll of the blade communicating with the first compression chamber is p ₁ . Since the compression chamber of the final chamber is formed between the fourth and fifth rolls of the blade, this pressure is set to P ₄₅ . It becomes the groove bottom space volume p ₄ of the fourth blade that communicates with the final compression chamber.

In this state, the spiral pitch shape of the blade groove 13 is set so that the pressure ratio falls within the range of (P ₄₅ + p ₄ ) / (P ₁₂ + p ₁ ) = 3 to 12.

When the relational expression between the pressure ratio and the volume ratio in consideration of the polytropic index described above is applied to the above embodiment, the discharge pressure Pd is Pd = {(V ₁₂ + v ₁ ) / (V ₄₅ + v ₄ )} ⁿ
・ It becomes Ps.

As a result, as shown in FIG. 4, the suction pressure Ps rises from the suction pressure Ps to the discharge pressure Pd in four rotations during the suction stroke, and there is no pressure loss up to this time, and a smooth and accurate predetermined discharge is achieved. Pressure will be obtained.

In the above embodiment, the blade 1
Although the number of turns n of 4 has been described as 5, the number of turns is not limited to this, and at least 5, preferably more turns may be provided. In any case, the compression performance can be improved by setting the volume ratio or the pressure ratio in the range set previously.

The application of the fluid compressor of the present invention is not limited to the refrigeration cycle. The present invention can be variously modified without departing from the scope of the invention.

[0052]

As described above, according to the present invention, the range of the compression chamber volume ratio or the range of the pressure ratio with respect to the number of turns of the blade is set as described above. Therefore, the reverse flow of the discharge gas can be prevented, the pressure loss can be reduced, and the compression performance can be improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a fluid compressor according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship among a piston, a blade, and a compression chamber.

FIG. 3 is a pressure relationship between compression chambers on both sides of the blade, and an operation explanatory diagram based on the pressure relationship.

FIG. 4 is a diagram showing pressure rise characteristics of the above embodiment.

FIG. 5 is a diagram showing pressure rise characteristics of a conventional structure.

[Explanation of symbols]

2 ... Cylinder, 6 ... Main bearing, 7 ... Sub bearing, 10 ... Rotating body (piston), 13 ... Blade groove, 14 ... Blade, V
... compression chamber, 17 ... rotational force transmission mechanism.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Motokatsu 70 Yanagimachi, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Yanagimachi factory

Claims (2)

[Claims] 1. A cylinder whose both ends are held and is rotatably supported, a suction part and a discharge part provided on the cylinder, and both end shaft parts thereof are rotatably supported eccentrically to the cylinder. A rotary member arranged such that a part of the peripheral wall is in contact with the inner peripheral wall of the cylinder; and a spiral member provided on the peripheral surface of the rotary member, the pitch of which gradually decreases from the suction unit toward the discharge unit. The blade groove, the blade wound so as to project into and retract from the blade groove, the cylinder and the rotating body are rotated in synchronization with each other, and the fluid to be compressed is introduced from the suction section to allow the cylinder, the rotating body, and It is taken into the compression chamber, which is a space chamber formed by the blade, and is sequentially transferred in the direction of the discharge part, and is compressed as the volume of the compression chamber is reduced. Provided with blades of turns: n suction side first chamber th compression chamber volume: V ₁ groove bottom space volume of the blade 1 tum communicating with the compression chamber:
v _a compression chamber volume of the discharge-side end chamber: V _n-1 blade end before winding-th groove bottom space volume communicating with the compression chamber: v when the _{b, (V 1 + v a} ) / (V n- ₁ + v _b) = _3~12 of such volume ratio equation is satisfied, a fluid compressor, characterized in that setting the helical pitch shape of the blade groove. 2. A cylinder, which is rotatably supported at its both ends in a sealed state, a suction part provided at one end of the cylinder, and a discharge part provided at the other end, and both ends thereof. A rotating body whose shaft portion is eccentrically and rotatably supported by a cylinder, and a peripheral wall of which is arranged to abut on the cylinder inner peripheral wall, and a rotating body which is provided on the peripheral surface of the rotating body and is provided from the suction portion to the discharge portion. The spirally formed blade groove with the pitch gradually decreasing toward the blade, the blade wound so as to project into and retract from the blade groove, and the cylinder and the rotating body are rotated in synchronization with each other to compress the fluid to be compressed. Introduced from the suction part, taken into the compression chamber which is a space chamber formed by the cylinder, the rotating body and each blade, sequentially transferred in the discharge part direction, and compressed as the volume of the compression chamber is reduced to a predetermined pressure. When compressed The fluid compressor comprising a rotation force transmission mechanism for ejecting from the ejection unit, the blade of the number of turns: n suction side first chamber th compression chamber pressure: P ₁ groove bottom space of the blade 1 tum communicating with the compression chamber pressure:
p _a Pressure in compression chamber of discharge-side final chamber: P _n-1 Pressure of groove bottom space in front of the blade last communicating with this compression chamber: p _b , (P _n-1 + p _b ) / (P ₁ + p _a) = so that the pressure ratio equation 3-12 is satisfied, a fluid compressor, characterized in that setting the helical pitch shape of the blade groove.