JP2797452B2 - Scroll compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scroll compressor, and more particularly, to a scroll compressor with a capacity control function.

(Prior Art) Conventionally, this kind of scroll compressor has been disclosed in Japanese Patent Laid-Open No. 63-134894.
It was configured as disclosed in Japanese Patent Publication No. FIG. 4 shows an example in which the scroll compressor disclosed in the above-mentioned publication is applied to a hermetic refrigerant compressor, and the configuration will be described with reference to FIG. In FIG. 4, reference numeral 1 denotes a fixed scroll having a spiral projection 1b on the lower surface of a base plate portion 1a, and 2 denotes a base plate portion.
A swinging scroll provided with a swirling projection 2b on the upper surface of 2a and a swinging shaft 2c protruding below the center of the base plate 2a, 5 is a compression chamber formed by combining the respective swirling projections 1b and 2b, 3 Is a suction port formed on the outer periphery of each of the scrolls 1 and 2, 4 is a discharge port provided at the center of the base plate 1a of the fixed scroll 1, 6
Is a main shaft having an eccentric hole 6b in a large diameter portion 6a formed at the upper end,
Reference numeral 7 denotes an oscillating bearing which is fitted in the eccentric hole 6b and supports the oscillating shaft portion 2c in the radial direction. Reference numerals 8 and 9 denote motor rotors and motor stators for driving the main shaft 6, and reference numeral 10 denotes when the main shaft 6 is driven. An Oldham coupling that regulates the orbiting scroll 2 so as to perform a revolving motion that does not rotate, a sealed container 11 that accommodates each component,
Reference numeral 12 denotes a suction pipe fixed to the closed container 11, reference numeral 13 denotes a discharge pipe fixed to the fixed scroll 1 for sending the compressed gas from the discharge port 4 out of the closed container 11, and reference numeral 14 denotes a base plate of the fixed scroll 1.
Fluid bypass hole provided in 1a, 15 is a fluid bypass hole 14
, 16 is a concentric slit provided outside the fluid bypass hole 14, and 17 is the base plate portion 1a.
, A discharge hole communicating the outer periphery of the fixed scroll 1 with the slit 16, a bypass valve 18 consisting of a circular plate-shaped valve,
19 is a valve seat plug which closes the upper part of the valve seat 15 and serves as a stopper of the bypass valve 18, 20 is a valve seat space between the valve seat 15 and the valve seat plug 19,
Reference numeral 21 denotes a communication hole provided at the center of the valve seat plug 19, and reference numeral 22 denotes a communication hole 21 of the valve seat plug 19 and the closed container 11 for guiding suction pressure and discharge pressure by switching a three-way solenoid valve or the like (not shown). A pressure pipe fixed to the pipe hole 23 by brazing or the like is shown, and a coil spring 24 disposed in the slit 16 is shown. In such a scroll compressor, since the fixed scroll 1 and the orbiting scroll 2 are combined to form a plurality of symmetrical compression chambers 5 at the same time, the fluid bypass hole 14 also corresponds to at least the pair of compression chambers 5. And a pair is formed at symmetrical positions.

In the above-described conventional scroll compressor, when the motor rotor 9 rotates, the main shaft 6 rotates, and the orbiting scroll 2 revolves while being prevented from rotating by the Oldham coupling 10. As a result, a part of the refrigerant gas sucked from the suction pipe 12 becomes the motor rotor 9 and the motor stator.
While cooling 10, it is taken into the compression chamber 5 through the suction port 3, gradually compressed and discharged from the discharge port 4 to the discharge pipe 13.

When the compressor is operated at the maximum capacity without controlling the capacity, the discharge pressure is guided to the pressure pipe 22 by switching the three-way solenoid valve and the like, whereby the pressure in the valve seat space 20 becomes the discharge pressure and the discharge pressure is supplied to the bypass valve 18. Act, the bypass valve 18 is pressed downward and adheres closely to the valve seat, and the fluid bypass hole 14 and the slit 16
Is closed by a bypass valve 18, and the fluid in the compression chamber 5 is not discharged to the outside of the fixed scroll 1 communicating with the suction space through the fluid bypass hole 14, the slit 16, and the discharge hole 17, and It is discharged outside.

Further, when controlling the capacity of the compressor, the suction pressure is led to the pressure pipe 22 by switching the three-way solenoid valve or the like, whereby the pressure in the valve seat space 20 becomes the suction pressure. Fluid bypass hole
14 is provided in the middle of the compression process of the compression chamber 5,
The pressure in the compression chamber 5 communicating with the fluid bypass hole 14 is higher than the suction pressure. In addition, the bypass valve 18 is pushed upward by the elastic force of the coil spring 23 disposed in the slit 16, is held in contact with the valve seat plug 18, and the fluid bypass hole 14 and the discharge hole 17 are in the valve seat space. 20 through the slit 16 and a part of the fluid in the compression chamber 5
4. The air is discharged to the outside of the fixed scroll 1 communicating with the suction space through the slit 16, the discharge hole 17, and the compression capacity in the compression chamber 5 is controlled.

(Problems to be Solved by the Invention) In the above-mentioned conventional scroll compressor, there is a regulation on the position where the fluid bypass hole is provided.
In the example disclosed in Japanese Patent Publication No. 134894, in the range from the most upstream position where the compression chamber is formed by the completion of the closing of the fluid by the fixed scroll and the orbiting scroll, and the position immediately before the compression chamber communicates with the discharge port, It is shown to be movable, and, in the examples disclosed in JP-A-57-148089 and JP-A-60-98193, when the extension angle of the outermost end of the fixed scroll is θ, Assuming that the expansion angle indicating the position where the fluid bypass hole is provided is ρ, a pair of fluid bypass holes is provided in the range of θ−2π <ρ <θ.

By the way, as an advantage of the scroll compressor with the capacity control function, in a so-called multi air conditioner in which a plurality of indoor units are installed for one outdoor unit, the capacity of the outdoor unit, that is, the compressor, varies with respect to load fluctuation on the indoor side. The following operation prevents the compressor from being frequently started and stopped, prevents the loss of compression power, and enables efficient operation. However, when the fluid bypass hole is provided at the latter position, for example, when the expansion angle θ is 6π or more,
During capacity control operation, the compression power loss is small and the performance decrease is small, but a large capacity reduction ratio cannot be obtained, and it is not enough to prevent frequent start / stop of the compressor.

In addition, when the fluid bypass hole is provided at the former position, and when the expansion angle is 6π or more, the position of the fluid bypass hole is changed to the time when the compression of the fluid is completed and the compression chamber is formed. If it is provided 180 ° upstream of the most upstream position that forms a complete compression chamber that is not in communication with the discharge port, the capacity ratio when capacity control is performed and when capacity control is not performed increases, but at the same time The compression power loss also increases, and the operation efficiency during capacity control operation deteriorates and energy conservation may be adversely affected.The purpose of the present invention is to solve such a conventional problem. It is an object of the present invention to provide a scroll compressor with a capacity control function that can take full advantage of the capacity control function by balancing the loss increase ratio. Another object of the present invention is to provide a scroll compressor capable of controlling a wide range of capacity.

[Means for solving the problem]

The scroll compressor according to the present invention includes a fixed scroll provided with a spiral projection below the base plate and a discharge port in the center, and a compression chamber provided with a spiral projection on the base plate and combined with the fixed scroll. Forming a swinging scroll which, when driven, swings and cooperates with the fixed scroll to compress the volume of the fluid, and the compression chamber provided on the base plate portion of the fixed scroll has the discharge port. A pair of fluid bypass holes that communicate before communication, a bypass valve that opens and closes the fluid bypass hole, means for operating the bypass valve, and a fixed scroll that communicates the fluid bypassed from the fluid bypass hole to the suction pressure space. In the scroll compressor having a capacity control function including a discharge hole for discharging to the outside, the extension angle of the outermost end of the fixed scroll spiral projection is θ.
1. When the number of turns of the spiral projection is N, 0.5 ≦ (2n
−1) / (2N−1) ≦ 0.6 is determined, and the first hole of the pair of fluid bypass holes is expanded angle θ2 = θ1− (N−
n) The base plate portion inside the spiral protrusion at the position of 2 × 2π is provided adjacent to the spiral protrusion, and the second hole has an extension angle θ3 = θ1− (N−n + 1/2) × 2π. At a position adjacent to the spiral projection on the base plate portion outside the spiral projection at the position of N, and N = 3 and θ1 = 6π.

(Operation) According to the scroll compressor of the present invention, the loss due to being once compressed and then returned to the suction space and recompressed is added, thereby avoiding a range where the loss increase rate suddenly increases and reducing the capacity ratio. Can be smaller.

(Embodiment) Hereinafter, a scroll compressor of the present invention will be described in more detail with reference to an embodiment shown in the accompanying drawings.

FIG. 1 shows spiral scrolls 1b and 2b of a fixed scroll 1 and an orbiting scroll 2 by a scroll compressor according to an embodiment of the present invention.
The cross-sectional view of the fixed scroll 1 when viewed from the base plate portion 1a of the fixed scroll 1 as a bottom surface, 14a and 14b are a pair of fluid bypass holes, and the outermost end of the spiral projection 1b of the fixed scroll 1 is extended. An example is shown in which the opening angle θ ₁ = 6π and the number of turns N of the spiral projection is N = 3. Therefore, the first hole 14 of the fluid bypass hole 14
a is the base plate inside the spiral protrusion 1b at the position of the spread angle θ ₂ = θ ₁ − (N−n) × 2π determined by n that satisfies 0.5 ≦ (2n−1) / (2N−1) ≦ 0.6. The portion 1a is adjacent to the spiral projection 1b, and the second hole 14b has an extended angle. Is provided adjacent to the spiral projection 1b on the base plate portion 1a inside the spiral projection 1b. In FIG. 2, the extension angle θ =
In the case of 6π, the number of turns of the spiral projection N = 3, 0.5 ≦ 2n−1
/2N-1≦0.6, which indicates the installation possible range of the fluid bypass holes 14a and 14b defined by n (A indicates the first hole installation range, and B indicates the second hole installation range) It is.

FIG. 3 shows a scroll compressor in which the volume of fluid taken in per rotation by the fixed scroll 1 and the orbiting scroll 2 is 50 cc, the outermost angle of the spiral projection is θ = 6π, and the number of turns of the spiral projection is N = 3. 7 is a graph showing a relationship between a capacity ratio by capacity control ON-OFF depending on a position of a first fluid bypass hole 14 and a loss increase rate due to a compression power loss at the time of capacity control. At this time, the diameter of the fluid bypass hole 14 is set to a certain value.

Here, the position of the first fluid bypass hole is 0.5 ≦ 2n−1 / 2.
The value of n that satisfies N−1 ≦ 0.6 is obtained, and the spread angle θ ₂ = θ ₁ − (N−
n) × 2π. Therefore, in the above-described example, the spiral protrusion 1b is provided adjacent to the spiral protrusion 1b at the position of the spread angle of 4π to 3.5π. The loss increase ratio is obtained by calculating the theoretical compression power in a certain operation state and the compression power loss during capacity control, and calculating the ratio of (theoretical compression power + compression power loss) / theoretical compression power.

In the graph of FIG. 3, if the position of the first fluid bypass hole is 4π, the capacity ratio is about 0.6, the loss increase rate is about 1.2, and if the position is 3.5π, the capacity ratio is about 0.5, and the loss increase rate is about 0.5. It is about 1.24. As can be seen from the graph of FIG. 3, the capacity ratio changes almost linearly with respect to the position of the first fluid bypass hole, but the loss increase rate is smaller than that of the position of the first fluid bypass hole of about 3.5π. The rise becomes steep from the vicinity of the decrease, indicating that the rate of increase is increasing. The advantage of the capacity control function is that the capacity of the compressor is varied with respect to load fluctuations and efficient operation is performed.
The provision of a fluid bypass hole must be avoided. Further, when the first fluid bypass hole is provided at the position of 5π, the capacity ratio of the compressor becomes about 0.8, and the compressor cannot sufficiently follow the fluctuation of the load, and the compressor repeatedly starts and stops. Therefore, as shown in the present embodiment, by limiting the installation range of the fluid bypass hole, it is possible to obtain a compressor that can fully utilize the merit of the capacity control function that balances the capacity ratio and the loss increase rate.

〔The invention's effect〕

As described above, in the scroll compressor of the present invention, in the scroll compressor with the capacity control function, when the outermost angle of the outermost end of the fixed scroll spiral projection is θ1, and the number of turns of the spiral spiral projection is N, 0.5 ≦ (2n-1) / (2N-1)
≤0.6 is determined, and the first hole of the pair of fluid bypass holes is provided on the base plate portion inside the spiral protrusion at the position of the expansion angle θ2 = θ1− (N−n) × 2π. The second hole is provided adjacently, and the extension angle θ3 = θ1− (N−n + 1 /
2) N = 3, θ1 = 6π, provided adjacent to the spiral projection on the base plate portion outside the spiral projection at a position of × 2π.
Therefore, once compressed, the loss due to being returned to the suction space and recompressed is added, avoiding the range where the loss increase rate suddenly increases, and reducing the capacity ratio,
It is possible to obtain a compressor that can take advantage of the capacity control function that balances the capacity ratio and the loss increase rate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a combination state of a fixed scroll and a swirling projection of an orbiting scroll of a scroll compressor according to one embodiment of the present invention, and FIG. 2 is an installation range of a fluid bypass hole in a base plate portion of the fixed scroll. FIG. 3 is a graph showing the relationship between the capacity ratio and the rate of loss increase during capacity control depending on the position of the first fluid bypass hole, and FIG. 4 is a longitudinal section of a scroll compressor with a conventional capacity control function. FIG. 1 ... fixed scroll, 1a ... base plate, 1b ... spiral projection, 2 ... swinging scroll, 2b ... spiral projection, 14a ...
1st fluid bypass hole, 14b ... 2nd fluid bypass hole. In the drawings, the same reference numerals indicate the same or corresponding parts.

Continuation of the front page (56) References JP-A-57-148089 (JP, A) JP-A-60-98193 (JP, A) JP-A-63-134894 (JP, A) (58) Fields investigated (Int) .Cl. ⁶ , DB name) F04C 18/02 311

Claims (1)

(57) [Claims] A fixed scroll provided with a spiral projection below the base plate portion and a discharge port at a center portion; and a spiral projection provided on the base plate portion and combined with the fixed scroll to form a compression chamber. And a oscillating scroll that oscillates when driven and compresses the volume of fluid in cooperation with the fixed scroll, and before the compression chamber provided on the base plate portion of the fixed scroll communicates with the discharge port. A pair of fluid bypass holes communicating with the, a bypass valve for opening and closing the fluid bypass hole,
A scroll compressor having a capacity control function, comprising: means for operating the bypass valve; and a discharge hole for discharging the fluid bypassed from the fluid bypass hole to the outside of the fixed scroll communicating with the suction pressure space. When the extension angle of the outermost end of the spiral projection is θ1 and the number of turns of the spiral projection is N, 0.5 ≦ (2n−1) / (2N−1) ≦ 0.6
Is obtained, and the first hole of the pair of fluid bypass holes is provided on the base plate portion inside the spiral projection at the position of the expansion angle θ2 = θ1− (N−n) × 2π. The second hole is provided adjacently and the divergence angle θ3 = θ1− (N−n +
1/2) × 2π, provided on the base plate portion outside the spiral projection at a position adjacent to the spiral projection, N = 3, θ1 = 6
A scroll compressor characterized by π.