JP2010196593A - Scroll fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll fluid machine capable of automatically controlling the capacity according to operational conditions, eliminating the need for complicate branched pipes, reducing the production costs to a significant degree and simultaneously carrying out highly responsive capacity control and back pressure control. <P>SOLUTION: In the scroll fluid machine applying back pressure from the anti-working chamber side to the working chamber side to at least one of the turning scroll or non-turning scroll, a capacity control means capable of controlling a back pressure according to operational conditions is provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a scroll fluid machine, for example, a scroll fluid machine suitable for a scroll compressor, a scroll vacuum pump, a scroll blower, and the like that handle a compressive gas or liquid such as a refrigerant as a working fluid.

  A conventional scroll fluid machine is disclosed in Japanese Patent Application Laid-Open No. 2000-314382 (Patent Document 1).

  The scroll fluid machine includes a working chamber formed by meshing a rotating scroll and a non-rotating scroll each having a spiral wrap on each base plate (end plate), a stator (stator), and a rotor (rotor). And a shaft that transmits the rotational force of the rotor through the rotor. The orbiting scroll performs an orbiting motion with respect to the non-orbiting scroll while being prevented from rotating by the rotation preventing mechanism. The working fluid that has flowed into the working chamber from the suction port installed in the non-orbiting scroll gradually decreases in volume as the shaft rotates, compresses the working fluid, and discharges installed in the non-orbiting scroll. It is discharged from the outlet and sent from a discharge pipe installed in a sealed casing to a refrigeration cycle connected to a scroll fluid machine.

  Note that during the compression operation, the orbiting scroll and the non-orbiting scroll are affected by the increased pressure in the working chamber, and the force in the direction away from each other acts. Increase. Therefore, in order to maintain a good seal of the working chamber and suppress leakage of the working fluid, a back pressure that is a supporting force in a direction in which the orbiting scroll and the non-orbiting scroll are brought close to each other is applied. . The back pressure has an appropriate value according to each operating condition. If the back pressure is too small, leakage loss increases. Friction loss generated on the surface increases, which causes the efficiency and reliability of the scroll fluid machine to deteriorate.

  On the other hand, the operation mode of the refrigeration cycle is diversified, and further expansion of the operation range is desired for the scroll fluid machine. However, the scroll fluid machine has a fixed compression ratio and pushing amount that are determined by the specifications of the scroll wrap regardless of variations in load such as discharge pressure and suction pressure of the refrigeration cycle. Therefore, for example, a release valve mechanism or the like in which the working chamber communicates with the discharge space is provided on the end plate of the non-orbiting scroll so as not to perform an excessive compression operation even when the operation condition is equal to or less than the set compression ratio. In addition, by controlling the electric motor that drives the scroll fluid machine with an inverter and making the rotational speed of the electric motor variable, it is possible to secure a suitable circulating amount of the working fluid to be supplied to the refrigeration cycle even with a constant amount of pushing. Furthermore, there is also a means for controlling the capacity by reducing the apparent pushing amount by bypassing the working fluid during or after the compression to the suction space.

  In order to increase the efficiency and reliability of the scroll fluid machine, it is necessary to bypass the working chamber and the suction pipe to reduce the apparent pushing amount, which is excessive compared to the normal operation. Therefore, it is necessary to reduce the back pressure to prevent an increase in friction loss. In Patent Document 1, as the method, a capacity control pipe 81 branched from a suction pipe 71 and a discharge pipe 72 is connected to a bypass valve 15 communicating with a working chamber installed on an end plate of a non-orbiting scroll. At the same time, the capacity control pipe is connected to the back surface of the back pressure control valve 13. Here, the capacity control pipe is provided with a three-way valve 80 for switching between normal operation and capacity control, and a control signal generated outside the compressor according to the operating conditions of the refrigeration cycle. It is electrically controlled by.

  During normal operation, the capacity control pipe 81 connected to the bypass valve 15 and the back pressure control valve 13 communicates with the discharge pipe by the three-way valve 80 to generate a high discharge pressure, the bypass valve does not open, and the capacity is not controlled. . Further, the spring force of the back pressure control valve 13 is increased, and the back pressure is adjusted to be relatively high. On the other hand, during the capacity control, the inside of the capacity control pipe 81 connected to the bypass valve 15 and the back pressure control valve 13 communicates with the suction pipe 71 by the three-way valve 80 to become a low suction pressure, and the bypass valve 15 is opened and compressed. The capacity is controlled by returning the working fluid on the way into the suction pipe 71. Further, the spring force of the back pressure control valve 13 is lowered, and the back pressure is adjusted to be relatively low.

  Another scroll fluid machine is disclosed in Japanese Patent No. 4044793 (Patent Document 2). This scroll fluid machine contributes to higher efficiency by reducing the dead volume of the capacity control bypass hole. Moreover, the vibration of the valve body is suppressed by introducing a discharge pressure passing through a narrow passage to the back surface of the capacity control valve.

JP 2000-314382 A Japanese Patent No. 4044793

  However, in the conventional scroll fluid machine shown in Patent Document 1, since it is necessary to connect the suction pipe, the discharge pipe, the capacity control pipe, and the back pressure control pipe, the structure becomes complicated and the number of parts increases. However, there is a problem that the manufacturing cost increases. Moreover, since a three-way valve controlled by an electrical control signal from the inside of the piping where the working fluid branches or from the outside of the scroll fluid machine passes, there is a problem that a control response delay occurs. Furthermore, there is a problem that pressure loss and heating occur in the piping, which hinders high efficiency of the scroll fluid machine.

  In the conventional scroll fluid machine shown in Patent Document 2, there is no description about back pressure control, and there is a problem that means for performing back pressure control simultaneously with capacity control is not shown.

  The object of the present invention is to automatically control the capacity according to the operating conditions, eliminate the need for complicated branch pipes, etc., greatly reduce the manufacturing cost, and provide the capacity control and the back with excellent responsiveness. It is an object to provide a scroll fluid machine capable of simultaneously controlling pressure.

In order to achieve the above-mentioned object, the present invention comprises a working chamber formed by meshing a revolving scroll and a non-revolving scroll each having a spiral wrap on each end plate, and a suction formed on the end plate of the non-revolving scroll. In a scroll fluid machine comprising a space, a back pressure region formed on at least one reaction chamber side of the orbiting scroll or the non-orbiting scroll, and a back pressure control mechanism for controlling the pressure in the back pressure region,
The back pressure control mechanism controls the capacity by bypassing the working chamber and the suction space according to operating conditions.

  In the scroll fluid machine according to the present invention, the back pressure control mechanism controls the back pressure by bypassing the back pressure region and the suction space according to operating conditions, and also controls the capacity control of the fluid machine. In some cases, there is provided a movable valve portion that controls the capacity by bypassing the working chamber and the suction space.

  In the scroll fluid machine according to the present invention, the movable valve portion is a magnetic body, and the member that limits the movable range of the movable valve portion is a permanent magnet.

  In the scroll fluid machine according to the present invention, the back pressure control mechanism is controlled by an electrical signal.

The present invention also provides a working chamber formed by meshing a revolving scroll and a non-revolving scroll each having a spiral wrap on each end plate, a suction space formed in the end plate of the non-revolving scroll, and the revolving scroll Alternatively, in a scroll fluid machine comprising a back pressure region formed on at least one reaction chamber side of the non-orbiting scroll and a back pressure control mechanism for controlling the pressure in the back pressure region,
Furthermore, a capacity control mechanism that controls the capacity by bypassing the working chamber and the suction space according to operating conditions is provided, and the back pressure is controlled by the capacity control mechanism during the capacity control operation of the fluid machine. .

  In the scroll fluid machine according to the present invention, the capacity control mechanism may control the back pressure by bypassing the back pressure region and the suction space according to operating conditions, and at the time of capacity control operation of the fluid machine. The movable valve part which controls the capacity | capacitance by bypassing the said working chamber and the said suction space was provided.

  In the scroll fluid machine according to the present invention, the movable valve portion is a magnetic body, and a member that limits a movable range of the movable valve portion is a permanent magnet.

  In the scroll fluid machine according to the present invention, the capacity control mechanism is controlled by an electrical signal.

  Further, the present invention uses an asymmetric spiral wrap in which the spiral wrap end angle of either the orbiting scroll or the non-orbiting scroll is different from the other spiral wrap end angle in the scroll fluid machine described above. It is characterized by that.

  Further, the present invention forms a working chamber by meshing a revolving scroll and a non-revolving scroll, each of which has a spiral wrap standing on each end plate, and has a back surface on at least one reaction chamber side of the revolving scroll or the non-revolving scroll. In a scroll compressor with a pressure region, the compression chamber and suction space are bypassed during capacity control, the gas sucked into the compression chamber is not compressed immediately, and the apparent pushing amount is reduced by delaying the start of compression. A capacity control mechanism is provided, and the back surface pressure is simultaneously controlled by the capacity control mechanism.

  According to the scroll fluid machine of the present invention, it is possible to give a back pressure that suppresses sliding friction loss while controlling the capacity according to operating conditions with a simple structure and ensuring a good sealing performance of the compression chamber.

Sectional drawing of the scroll compressor compression mechanism in 1st Embodiment of this invention. 1 is a cross-sectional view of an entire scroll compressor according to a first embodiment of the present invention. The enlarged view of the back pressure control mechanism at the time of the normal driving | operation in 1st Embodiment of this invention. The enlarged view of the back pressure control mechanism at the time of capacity | capacitance control in 1st Embodiment of this invention. The enlarged view of the capacity | capacitance control mechanism in the time of normal operation in 2nd Embodiment of this invention. The enlarged view of the capacity | capacitance control mechanism at the time of capacity | capacitance control in 2nd Embodiment of this invention.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. The same reference numerals in the drawings of the respective embodiments indicate the same or equivalent. However, the present invention is not limited to the following embodiments. In addition, unless otherwise specified, the scope of the present invention is not intended to limit the scope of the present invention only to those embodiments, but is merely an illustrative example.

(First embodiment)
A scroll compressor 100 according to a first embodiment of the present invention will be described with reference to FIGS. First, the scroll compressor 100 will be described with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of a compression mechanism of a scroll compressor according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the entire scroll compressor.

  The scroll compressor 100 has a structure in which a compression mechanism that performs a compression operation and a drive mechanism including an electric motor are housed in the sealed casing 1.

  The compression mechanism uses the non-orbiting scroll 2, the orbiting scroll 3, and the frame 4 as basic elements. The non-orbiting scroll 2 and the orbiting scroll 3 are meshed to form a compression chamber 20.

  The non-orbiting scroll 2 has an end plate 2a and a spiral wrap 2b erected on the end plate 2a as basic components. A suction port 2c is formed in the outer peripheral portion of the end plate 2a. A suction pipe 16 is connected to the suction port 2c. A discharge port 2d is formed at the center of the end plate 2a. In addition, a release valve mechanism 14 is provided on the end plate 2a so that the compression chamber 20 and the discharge space 17 communicate with each other during an operation of a predetermined set compression ratio or less determined by the scroll lap specifications.

  On the other hand, the orbiting scroll 3 has an end plate 3a, a spiral wrap 3b erected on the end plate 3a, and a boss cylinder 3c erected on the back side of the end plate 3a as basic components. A slewing bearing 3d is provided in the boss cylinder 3c.

  The frame 4 is fixed to the hermetic casing 1 by welding or the like. The non-orbiting scroll 2 is fixed to the frame 4 with bolts or the like. The orbiting scroll 3 is disposed between the non-orbiting scroll 2 and the frame 4 so as to be orbitable. The frame 4 forms a back pressure chamber 13 as a back pressure region 23 on the back side of the orbiting scroll end plate 3a. Moreover, the back pressure control mechanism 19 is installed in the non-orbiting scroll end plate 2a, and the back pressure of the back pressure chamber 13 is adjusted between the discharge pressure and the suction pressure during operation.

  The orbiting scroll 3 is pressed against the non-orbiting scroll 2 by the back pressure of the back pressure chamber 13 during operation, and the sealing performance of the compression chamber 20 is improved. Here, a bypass hole 22 through which the back pressure control mechanism 19 and the compression chamber 20 communicate is provided in the non-orbiting scroll end plate 2a so that the capacity can be controlled according to the operating conditions.

  The driving mechanism for driving the orbiting scroll 3 to rotate is an electric motor 21 as an example of a rotation driving means, a shaft 7, an Oldham ring 8 which is a main part of the rotation preventing mechanism of the orbiting scroll 3, and an upper portion of the shaft 7. A swivel bearing 3d that engages with a main bearing 9 that engages with the shaft 7 and an eccentric portion of the shaft 7 in a rotational axis direction, and a sub-bearing that engages with a lower portion of the shaft 7 so as to rotate freely. 11 is a basic element. The sliding portion of the shaft 7 corresponds to a portion of the shaft 7 with respect to the main bearing 9, the slewing bearing 3d, the auxiliary bearing 11, and the like.

  The electric motor 21 is configured by an induction motor or the like, and includes an annular stator 5 and an annular rotor 6. The stator 5 is fixed to the hermetic casing 1 by shrink fitting or the like. The rotor 6 is rotatably disposed in the stator 5. On the upper and lower end surfaces of the rotor 6, balance weights 12, which are balanced parts for canceling out the unbalanced force caused by the movement of the orbiting scroll 3 and keeping the compressor vibration low, are installed.

  The electric motor 21 and the compression mechanism are arranged side by side in the longitudinal direction of the sealed casing 1, and are linked by the shaft 7. The frame 4 is disposed between the electric motor 21 and the compression mechanism. The shaft 7 is a cylindrical member that is installed through the rotor 6 of the electric motor 21 and transmits the rotational force of the rotor 6 to the compression mechanism. The upper portion of the shaft 7 is rotatably supported by the main bearing 9, the intermediate portion of the shaft 7 passes through the center portion of the rotor 6, and the lower portion of the shaft 7 is rotatably supported by the auxiliary bearing 11. The auxiliary bearing 11 is provided to ensure stable rotation of the shaft 7.

  The Oldham ring 8 is installed in the frame 4. One set of two orthogonal key portions formed on the Oldham ring 8 slides on the key groove formed on the frame 4, and the other set slides on the key groove formed on the back side of the orbiting scroll end plate 3a. .

  The main bearing 9 is built in the center of the frame 4. The auxiliary bearing 11 is built in the central portion of the auxiliary bearing member 10. The auxiliary bearing member 10 is disposed in the vicinity of the oil surface of the lubricating oil 15 on the anti-compression mechanism side of the electric motor 21 and is fixed to the sealed casing 1 by welding or the like. Note that a lubricating oil 15 is stored in a lower space in the sealed casing 1. The lower end of the shaft 7 is immersed in the lubricating oil 15.

  Next, the basic operation of the scroll compressor 100 will be described. A rotational force is applied to the rotor 6 by the rotating magnetic field generated by the stator 5, and the shaft 7 fixed to the rotor 6 rotates as the rotor 6 rotates. The orbiting scroll 3 is movably engaged with the eccentric portion of the shaft 7 so as to be movable in the direction of the rotation axis, and the rotational movement of the shaft 7 is caused to rotate by the rotation preventing mechanism such as the Oldham ring 8. Converted into motion. The volume of the compression chamber 20 formed by meshing the non-orbiting scroll 2 and the orbiting scroll 3 decreases as the orbiting scroll 3 orbits (compression stroke).

  In the compression operation, the working fluid such as the refrigerant is sucked into the compression chamber 20 through the suction pipe 16 and the suction port 2c as the turning scroll 3 turns. The sucked working fluid flows through the compression stroke in the compression chamber 20 to the discharge port 2d of the non-orbiting scroll, passes through the discharge space 17 in the hermetic casing 1, and finally from the discharge pipe 18 to the outside of the compressor. Exhaled.

  Further, the lubricating oil 15 accumulated in the lower space in the hermetic casing 1 is the difference between the discharge pressure in the discharge space 17 and the back pressure adjusted between the discharge pressure in the back pressure chamber 13 and the suction pressure. The slewing bearing 3d and the main bearing 9 are lubricated by the pressure and the centrifugal force accompanying the rotation of the shaft 7, and then supplied to the back pressure chamber 13. Thereafter, the lubricating oil 15 in the back pressure chamber 13 is supplied to the compression chamber 20, is discharged from the discharge port 2 d of the non-orbiting scroll together with the working fluid, and is separated in the discharge space 17 in the sealed casing 1. The separated lubricating oil 15 is stored in a lower space in the sealed casing 1.

  Next, the operation of the back pressure control mechanism during normal operation and capacity control will be described in detail with reference to FIGS. 3 and 4. FIG. 3 is an enlarged view of the back pressure control mechanism during normal operation. FIG. 4 is an enlarged view of the back pressure control mechanism during capacity control.

  The back pressure control mechanism 19 is installed in the non-orbiting scroll 2 and is composed of a back pressure control valve body 19a (movable valve portion), a back pressure control spring 19b, a needle 19c (movable valve portion), and an elastic body 19d. . The lower surface of the back pressure control valve element 19a communicates with the back pressure region 23, and the upper surface of the back pressure control valve element 19a communicates with the suction space 24 provided in the non-orbiting scroll end plate 2a. The suction space 24 communicates with the suction port 2c. A back pressure control spring 19b is installed between the needle 19c and the back pressure control valve body 19a, and the back pressure control valve body 19a is moved downward by a certain spring force by the elastic force of the back pressure control spring 19b. Is pushing.

  Further, the pressure of the discharge space 17 is introduced to the upper surface of the needle 19c, the elastic body 19d and the back pressure control spring 19b are compressed, and the needle 19c is pressed downward. The non-orbiting scroll 2 on the side surface of the needle 19 c is provided with a bypass hole 22 communicating with the compression chamber 20. A stopper 19e (a member that limits the movable range) is installed so that the needle 19c does not jump out of the non-orbiting scroll 2, and the pressure in the discharge space 17 from the side surface of the needle 19c A sealing material may be attached to the side surface of the needle 19 c so as not to leak into the space 24.

Here, the back pressure control method will be described. By the back pressure control mechanism 19,
When (the force due to the back pressure)> (the force due to the suction pressure) + (the elastic force of the spring 19b), the back pressure control valve body 19a moves upward and releases the back pressure in the back pressure region 23 to the suction space 24. Adjust the back pressure. That is, during normal operation, the position of the needle 19c is fixed, and the spring length of the back pressure control spring 19b is constant,
(Back pressure) = (Suction pressure) + (Constant value α) can be automatically controlled. During normal operation, the bypass hole 22 is closed at the side surface of the needle 19c, and the compression chamber 20 and the suction space 24 are not bypassed.

  On the other hand, the operating conditions that require capacity control generally have a smaller pressure difference between the discharge pressure and the suction pressure than during normal operation. Therefore, as shown in FIG. 4, during the capacity control, the needle 19c is pushed upward by using the elastic force of the elastic body 19d and the back pressure control spring 19b. When the needle 19c is pushed upward, the bypass hole 22 closed on the side surface of the needle 19c opens, and the compression chamber 20 and the suction space 24 bypass. Therefore, the compression chamber 20 in which the bypass hole 22 is opened becomes the suction space 24, and the apparent pushing amount can be reduced without performing the compression operation. That is, even if the rotation speed of the compressor is kept constant, the circulating amount of the working fluid is reduced and the capacity can be controlled.

At the time of capacity control, a part of the compression chamber 20 does not perform the compression operation, so that the back pressure required during normal operation is greatly reduced. Here, if the back pressure is excessive, friction loss generated on the sliding surfaces of the orbiting scroll 3 and the non-orbiting scroll 2 increases, and the efficiency and reliability of the scroll compressor are deteriorated. However, at the time of capacity control, the needle 19c is pushed upward, and the spring length of the back pressure control spring 19b becomes longer than that at the time of normal operation, so the elastic force becomes smaller, and (back pressure) = (suction pressure) It can be controlled to + (constant value β). That is, the elastic force determined by the spring length of the back pressure control spring 19b is
(Elastic force during normal operation (constant value α))> (Elastic force during capacity control (constant value β)), and the back pressure during capacity control should be controlled much lower than during normal operation. Can do.

  By using the needle 19c in the back pressure control mechanism 19 as a magnetic material and the stopper 19e as a permanent magnet having a constant magnetic force, the needle 19c is attracted to the stopper 19e by a magnetic force when the operating conditions are steady, and discharged. The needle 19c may be prevented from vibrating up and down with pulsation such as pressure so that noise is not generated.

  As described above, according to the present embodiment, the back pressure control mechanism is added with the function of opening and closing the bypass hole for capacity control, and during normal operation, the back pressure is automatically controlled to be high while the bypass hole is closed. In order to control the leakage loss of the compression chamber (while ensuring good sealability of the compression chamber), and at the time of capacity control, the bypass hole is opened, the apparent amount of pushing is reduced, and the capacity is automatically controlled, It is possible to automatically control the back pressure at a low level to suppress friction loss generated on the sliding surfaces of the orbiting scroll and the non-orbiting scroll, and to improve the efficiency and reliability of the scroll compressor.

  In addition, according to the present embodiment, since it has a simple structure that does not require complicated piping and the like, it suppresses an increase in manufacturing cost, has excellent control responsiveness, and suppresses pressure loss and heating during capacity control. A highly efficient scroll compressor can be obtained.

  In this embodiment, the means for mechanically automatically controlling the back pressure control and the capacity control according to the operating conditions has been described. However, in order to cope with the special operating conditions, an electrical control valve is provided in the back pressure control mechanism. (Not shown) may be attached. In the case of this electrical control, it is possible to respond quickly and easily to changes in operating conditions.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. 5 and 6 show a structure in which the capacity control mechanism is separated from the back pressure control mechanism. In FIGS. 5 and 6, the back pressure control mechanism is not shown, but the back pressure control mechanism having the function of adjusting the back pressure as described in the first embodiment is installed. Alternatively, the needle 19c of the back pressure control mechanism 19 is fixed by press-fitting or the like, the spring length of the back pressure control spring 19b is constant, and the hermeticity of the compression chamber 20 is sufficiently ensured under all operating conditions without capacity control. The back pressure control mechanism set to (back pressure) = (suction pressure) + (constant value) is installed. Alternatively, without using a valve as described in the first embodiment, a hole through which the back pressure chamber 13 and the compression chamber 20 communicate is provided in the end plate 3a of the orbiting scroll 3, and (back pressure) = (suction pressure) × ( A back pressure control mechanism that adjusts to a constant value may be used.

  FIG. 5 shows a capacity control mechanism during normal operation in the second embodiment of the present invention. The capacity control mechanism 25 is installed separately from the back pressure control mechanism in the non-orbiting scroll 2, and includes a capacity control valve body 25a (movable valve portion), a capacity control spring 25b, a needle 25c (movable valve portion), and an elastic body. 25d. The capacity control valve body 25 a has a protruding shape that substantially fills the bypass hole 22 communicating with the compression chamber 20 provided in the non-orbiting scroll 2. Further, the capacity control valve body 25 a has a tip shape that does not protrude into the compression chamber 20. One side of the capacity control valve body 25a is in the bypass hole 22 and communicates with the compression chamber 20, and the other side communicates with a suction space 24 provided in the non-orbiting scroll end plate 2a. A capacity control spring 25b is installed between the needle 25c and the capacity control valve body 25a, and the capacity control valve body 25a is pressed against the compression chamber side with a certain spring force by the elastic force of the capacity control spring 25b. ing.

  Further, the pressure of the discharge space 17 is introduced to one surface of the needle 25c, the elastic body 25d and the capacity control spring 25b are compressed, and the needle 25c is pressed against the compression chamber side. The back pressure region 23 communicates with the non-orbiting scroll end plate 2a on the side surface of the needle 25c. A stopper 25e is installed so that the needle 25c does not jump out of the non-orbiting scroll 2, and the pressure of the discharge space 17 from the side surface of the needle 25c does not leak into the back pressure region 23 or the suction space 24. A sealing material may be attached to the side surface of the needle 25c.

  During normal operation, since the position of the needle 25c is pressed against the compression chamber side and fixed, the capacity control spring 25b is strongly compressed, the bypass hole 22 is sealed, and capacity control is not performed. Further, the bypass hole 22, the suction space 24, the back surface region 23, and the discharge space 17 are sealed at the side surfaces of the capacity control valve body 25a and the needle 25c, and do not communicate with each other.

  On the other hand, the operating conditions that require capacity control generally have a smaller pressure difference between the discharge pressure and the suction pressure than during normal operation. Therefore, as shown in FIG. 6, at the time of capacity control, the elastic force of the elastic body 25d is used to move the needle 25c to the anti-compression chamber side. When the needle 25c moves to the side opposite to the compression chamber, the capacity control spring 25b becomes a natural length, pulls the capacity control valve body 25a away from the bypass hole 22, and bypasses the compression chamber 20 and the suction space 24. Therefore, the internal space of the compression chamber 20 in which the bypass hole 22 is open becomes a suction space 24, and the apparent amount of pushing can be reduced without performing a compression operation. That is, even if the rotation speed of the compressor is kept constant, the circulating amount of the working fluid is reduced and the capacity can be controlled.

  At the time of capacity control, a part of the compression chamber 20 does not perform the compression operation, so that the back pressure required during normal operation is greatly reduced. Here, if the back pressure is excessive, friction loss generated on the sliding surfaces of the orbiting scroll 3 and the non-orbiting scroll 2 increases, and the efficiency and reliability of the scroll compressor are deteriorated. However, at the time of capacity control, the needle 25c moves to the anti-compression chamber side, the back pressure region 23 and the suction space 24 communicate with each other, and the back pressure is reduced to the suction pressure. Alternatively, a back pressure adjusting groove 25f is provided in a part of the needle 25c, and the back pressure adjusting groove 25f is intermittently communicated with the back pressure region 23 as the needle 25c moves (while moving), thereby The pressure can be adjusted to a certain target value.

  In addition, the needle 25c in the capacity control mechanism 25 is made of a magnetic material, and the stopper 25e (a member that limits the movable range) is made of a permanent magnet having a constant magnetic force. The stopper 25e may be sucked so that the needle 25c suppresses vibration and does not generate noise with pulsation such as discharge pressure.

  As described above, according to this embodiment, the back pressure control mechanism is installed separately from the back pressure control mechanism. Is automatically controlled by the back pressure control mechanism, and at the time of capacity control, the compression chamber and suction chamber are bypassed, the apparent pressing amount is reduced to automatically control the capacity, and at the same time, the back pressure is automatically controlled to lower and turn Friction loss that occurs on the sliding surfaces of the scroll and the non-orbiting scroll can be suppressed, and the efficiency and reliability of the scroll compressor can be improved.

  Further, according to the present embodiment, a function can be added only by adding a capacity control mechanism, and an operation of embedding the capacity control mechanism in an existing back pressure control mechanism becomes unnecessary, and the specification can be easily changed. Furthermore, according to this embodiment, since it has a simple structure that does not require complicated piping, etc., it suppresses an increase in manufacturing cost, has excellent control responsiveness, and suppresses pressure loss and heating during capacity control. A highly efficient scroll compressor can be obtained.

  In the present embodiment, the means for automatically controlling the capacity control mechanically according to the operating conditions has been described. However, an electric control valve (not shown) is provided to the capacity control mechanism in order to cope with special operating conditions. May be attached. In the case of this electrical control, it is possible to respond quickly and easily to changes in operating conditions.

  In the previous embodiment and the present embodiment, the spiral wrap shape of the orbiting scroll and the non-orbiting scroll is the same as the spiral wrap end angle of either the orbiting scroll or the non-orbiting scroll. The present embodiment may be used in a scroll fluid machine having an asymmetric spiral wrap different from the above. Thereby, it can respond to the scroll fluid machine of various specifications.

  DESCRIPTION OF SYMBOLS 1 ... Sealed casing, 2 ... Non-orbiting scroll, 2a ... End plate, 2b ... Wrap, 2c ... Suction port, 2d ... Discharge port, 3 ... Revolving scroll, 3a ... End plate, 3b ... Wrap, 3c ... Boss cylinder, 3d Slewing bearing, 4 frame, 5 stator, 6 rotor, 7 shaft, 8 Oldham ring, 9 main bearing, 10 sub bearing member, 11 sub bearing, 12 balance weight, 13 back pressure Chamber, 14 ... Release valve mechanism, 15 ... Lubricating oil, 16 ... Suction pipe, 17 ... Discharge space, 18 ... Discharge pipe, 19 ... Back pressure control mechanism, 19a ... Back pressure control valve element (movable valve part), 19b ... back pressure control spring, 19c ... needle (movable valve part), 19d ... elastic body, 19e ... stopper (member that limits the movable range), 20 ... compression chamber, 21 ... electric motor, 22 ... bypass hole, 23 ... back surface Pressure region, 24 ... suction Space, 25 ... Capacity control mechanism, 25a ... Volume control valve element (movable valve part), 25b ... Capacity control spring, 25c ... Needle (movable valve part), 25d ... Elastic body, 25e ... Stopper (limit the movable range) 25f ... back pressure adjusting groove, 100 ... scroll compressor.

Claims (9)

Working chambers formed by meshing orbiting scrolls and non-orbiting scrolls each having a spiral wrap on each end plate, a suction space formed in the end plates of the non-orbiting scrolls, and at least the orbiting scrolls or the non-orbiting scrolls In a scroll fluid machine having a back pressure region formed on one reaction chamber side and a back pressure control mechanism for controlling the pressure in the back pressure region,
A scroll fluid machine characterized in that the capacity is controlled by bypassing the working chamber and the suction space according to operating conditions by the back pressure control mechanism.   2. The scroll fluid machine according to claim 1, wherein the back pressure control mechanism controls the back pressure by bypassing the back pressure region and the suction space according to operating conditions, and at the time of capacity control operation of the fluid machine. A scroll fluid machine comprising a movable valve unit that controls a capacity by bypassing an operation chamber and the suction space.   3. The scroll fluid machine according to claim 2, wherein the movable valve portion is a magnetic body, and the member that limits the movable range of the movable valve portion is a permanent magnet.   The scroll fluid machine according to any one of claims 1 to 3, wherein the back pressure control mechanism is controlled by an electrical signal. Working chambers formed by meshing orbiting scrolls and non-orbiting scrolls each having a spiral wrap on each end plate, a suction space formed in the end plates of the non-orbiting scrolls, and at least the orbiting scrolls or the non-orbiting scrolls In a scroll fluid machine having a back pressure region formed on one reaction chamber side and a back pressure control mechanism for controlling the pressure in the back pressure region,
And a capacity control mechanism that controls the capacity by bypassing the working chamber and the suction space according to operating conditions, and the back pressure is controlled by the capacity control mechanism during the capacity control operation of the fluid machine. Scroll fluid machine.   6. The scroll fluid machine according to claim 5, wherein the capacity control mechanism controls the back pressure by bypassing the back pressure area and the suction space according to operating conditions, and the operation is performed during the capacity control operation of the fluid machine. A scroll fluid machine comprising a movable valve portion that controls a capacity by bypassing a chamber and the suction space.   The scroll fluid machine according to claim 6, wherein the movable valve portion is a magnetic body, and a member that limits a movable range of the movable valve portion is a permanent magnet.   8. The scroll fluid machine according to claim 5, wherein the capacity control mechanism is controlled by an electrical signal.   9. The scroll fluid machine according to claim 1, wherein the spiral wrap end angle of either the orbiting scroll or the non-orbiting scroll is different from the other spiral wrap end angle. A scroll fluid machine characterized by using the above.

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