JP2008223757A - Device for reducing pulsation in variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently show pulsation reduction effect in a low flow rate state without causing enlargement of a variable displacement compressor by simplifying a pulsation reduction device. <P>SOLUTION: A back pressure valve 55 rises during low displacement operation. Rise of the back pressure valve 55 induces a spool valve to be pushed up by a compression spring 54 and to close an opening part 44. Consequently, an intake passage 32 is restricted and transmission of intake pulsation due to self-excited oscillation of an intake valve is prevented. Since a cavity is blocked by the back pressure valve 55 and a circulation hole 52 and the intake passage 32 are under a communication condition when intake pulsation of specific frequency is generated, a damper chamber 58 resonates with the intake pulsation transmitted to the intake passage 32 and Helmholtz resonance effect takes place. As a result, intake pulsation of the specific frequency is attenuated, high intake pulsation reduction effect due to synergy with restriction effect can be provided, and transmission of intake pulsation to an outside can be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a device for reducing pulsation generated in a variable capacity compressor.

  In variable capacity compressors, suction pulsation due to self-excited vibration of the suction valve occurs during low flow rate operation such as startup and variable capacity operation, and the vibration propagates out of the compressor and causes large vibrations. There is a problem that abnormal noise is easily generated. For this reason, various methods have been proposed in the past for reducing the pressure fluctuation during low flow rate operation and reducing the suction pulsation by controlling the flow area of the refrigerant gas in the suction passage upstream of the suction valve.

  For example, in Patent Document 1, an opening control valve 22 for controlling the opening area of the gas passage 18 is provided in the suction port 17 of the variable capacity compressor, and the opening area of the gas passage 18 is reduced when the suction flow rate is small. A configuration is disclosed in which the pulsation of the suction pressure generated by the self-excited vibration at the time of a low flow rate of the suction valve is reduced when the suction flow rate is large.

  Specifically, a valve chamber 21 is provided between the gas passage 18 and the suction port 17, and an opening degree control valve 22 is disposed in the valve chamber 21. The opening control valve 22 is urged toward the suction port 17 by the spring 23 and moves up and down due to a pressure difference between the suction chamber 16 and the suction port 17. The opening control valve 22 is set to maximize the opening area of the gas passage 18 when it is lowered most, and to minimize the opening area of the gas passage 18 when it is raised most. The valve chamber 21 communicates with the suction chamber 16 through the communication hole 24, and communicates with the suction port 17 through a valve hole 25 formed in the opening degree control valve 22.

  At the time of low flow operation, since the pressure difference between the suction chamber 16 and the suction port 17 is small, the opening degree control valve 22 is raised and the opening area of the gas passage 18 is reduced. At this time, a part of the refrigerant gas enters the valve chamber 21 through the valve hole 25 and further flows into the suction chamber 16 through the communication hole 24. The pressure pulsation of the refrigerant gas generated during the low flow rate operation propagates from the suction chamber 16 to the communication hole 24, further propagates through the valve chamber 21 from the valve hole 25 to the suction port 17, and the pressure pulsation is weakened in this process. Since it is rectified, it does not cause noise. That is, the propagation of pressure fluctuations to the low pressure side of the refrigeration circuit is suppressed by the volume effect of the suction chamber 16 and the throttling effect of the valve hole 25.

4 and 5 of Patent Document 2 disclose a pulsation reducing device in a variable capacity compressor described below.
That is, the suction passage 21 that connects the suction port 20 and the suction chamber 15 is formed with a muffler 22 for reducing suction pulsation, and an opening degree that adjusts the opening degree of the suction passage 21 upstream of the muffler 22. A valve chamber 23 of the control valve V is formed. A bottomed cylindrical valve body 29 and a movable body 30 are movably accommodated in the valve chamber 23 of the opening control valve V, and a spring 31 is disposed between the valve body 29 and the movable body 30. A stopper 23 b that restricts the movement of the valve body 25 and a stopper 32 that restricts the movement of the movable body 30 are disposed on the inner wall of the valve chamber 23. The suction pressure Ps is in the direction of opening the suction port 24 via the suction passage 21 on the front surface of the valve body 29, and the pressure of the crank chamber 5 is in the direction of closing the suction port 24 on the rear surface of the movable body 30 via the communication passage 26. Pc is acting respectively.

At the time of start-up from the OFF capacity operation or the variable capacity operation, the pressure Pc of the crank chamber 5 becomes higher than the suction pressure Ps, so that the valve body 29, the movable body 30 and the spring 31 move forward in the valve chamber 23 and Acts in the direction of closing. In a state where the movable body 30 is in contact with the stopper 32, the valve body 29 receives the urging force of the spring 31 and restricts the suction port 24 to a slightly opened state. be able to. A damper effect can be obtained by sealing the space between the valve body 29 and the movable body 30, and the generation of noise due to the vibration of the valve body 29 itself due to suction pulsation can be prevented.
JP 2000-136776 A JP 2006-207484 A

The pulsation reducing device disclosed in Patent Document 1 includes a valve in addition to the muffler effect generated between the suction chamber 16, the gas passage 18 and the suction port 17 when the gas passage 18 is throttled by the opening control valve 22 at a low flow rate. By connecting the chamber 21 to the suction chamber 16 and the suction port 17 through the communication hole 24 and the valve hole 25, respectively, a muffler effect generated between the suction chamber 16, the communication hole 24, the valve chamber 21, the valve hole 25, and the suction port 17 is obtained. This is used to reduce pulsation.
However, the pulsation generated at low flow rate cannot be sufficiently suppressed only by utilizing the muffler effect.

  In the pulsation reducing device disclosed in Patent Document 2, an extra muffler 22 is formed in the suction passage 21 that communicates the suction port 20 and the suction chamber 15, and the muffler 22 is operated by the valve element 29 of the opening control valve V when the flow rate is low. A larger muffler effect is aimed at by narrowing down the suction port 24. However, the additional formation of the muffler 22 causes an increase in the size of the variable capacity compressor, and there is a problem that it cannot cope with a limited space such as an engine room of a vehicle, for example. In addition, the effect of reducing the pulsation generated at a low flow rate cannot be obtained as compared with the downside of increasing the size of the variable capacity compressor.

  An object of the present invention is to simplify the pulsation reducing device so that the effect of reducing the pulsation at a low flow rate can be sufficiently exhibited without causing an increase in the size of the variable capacity compressor.

  The invention of claim 1 includes a crank chamber provided with a piston reciprocating mechanism, a suction chamber for supplying refrigerant gas into the cylinder bore, and a discharge chamber for discharging compressed refrigerant gas in the cylinder bore, The refrigerant gas discharge capacity is changed by controlling the pressure in the crank chamber, and a control valve including at least a spool valve and a damper chamber is disposed in a piping system that forms the refrigerant gas flow passage to distribute the refrigerant gas. In a variable capacity compressor that suppresses pulsation by controlling, the refrigerant gas acting on the spool valve is circulated into the damper chamber through a flow hole and the cross-sectional area and length of the flow hole are identified. The frequency is set based on the frequency and the volume of the damper chamber at the specific frequency, and when the pulsation of the specific frequency occurs, And characterized in that foster resonance effect.

  According to the present invention of claim 1, the Helmholtz resonance effect can be cultivated in addition to the throttling effect of the refrigerant gas flow passage with a simple configuration, and both effects can sufficiently reduce the pulsation generated during low flow operation. Can be planned.

  According to a second aspect of the present invention, in the spool valve and the spool valve, the control valve is installed in a suction passage which is a flow passage of the refrigerant gas to the suction chamber, and is displaced by receiving the pressure of the refrigerant gas. The spool comprises a back pressure valve that is disposed oppositely and is displaced by receiving pressure from the crank chamber, the spool valve, the damper chamber formed between the back pressure valve, and a compression spring provided in the damper chamber, A specific frequency in the pulsation and a specific frequency in which a flow hole for the refrigerant gas is formed in a valve, a vent hole communicating with the suction chamber is connected to the damper chamber, and a cross-sectional area and a length of the flow hole are generated In this case, the volume of the damper chamber, the suction chamber, the vent hole, and the communication passage connecting the suction chamber and the vent hole is set based on the volume of the refrigerant gas to the spool valve. Formation of flow holes That can get a Helmholtz resonator that utilizes the damper chamber with a simple configuration to say.

  According to a third aspect of the present invention, the vent hole connected to the damper chamber is arranged in a movement path of the back pressure valve, and the opening amount of the vent hole is changed from a fully closed state to a fully opened state by the movement position of the back pressure valve. The damper chamber can be changed to a closed space only at a specific low flow rate, and the damper chamber of the control valve installed to throttle the refrigerant gas intake passage. The Helmholtz resonance effect can be obtained by effectively utilizing

  The present invention can reduce the pulsation at a low flow rate with a simple configuration.

(First embodiment)
The configuration of the first embodiment will be described with reference to FIGS. The variable capacity compressor shown in FIG. 1 has the left side as the front and the right side as the rear for convenience of explanation.
As shown in FIG. 1, a front housing 12 is joined to one front end of the cylinder block 11, and a rear housing 13 is joined to the other rear end. A space defined by the cylinder block 11 and the front housing 12 constitutes a crank chamber 14.

  A rotating shaft 15 that passes through the crank chamber 14 is rotatably supported by the cylinder block 11 and the front housing 12. The front end of the rotating shaft 15 protrudes to the outside of the front housing 12 as a protruding end, and this protruding end receives a rotational force transmitted from a driving source (not shown) such as an engine or a motor of the vehicle (not shown). Z)).

  A rotating shaft 15 in the crank chamber 14 is provided with a swash plate 17 to which the rotating support 16 is fixed and engaged with the rotating support 16. The swash plate 17 is in a state in which the rotary shaft 15 passes through a through hole 18 formed at the center thereof, and a guide pin 19 formed to protrude from the swash plate 17 is formed in a guide hole 20 formed in the rotary support 16. It is slidably inserted in. The swash plate 17 rotates integrally with the rotary shaft 15 based on the relationship of the insertion of the guide pins 19 into the guide holes 20. The rotary support 16, the swash plate 17, the guide pin 19, and the guide hole 20 constitute a reciprocating mechanism according to the present invention. The swash plate 17 is supported by the rotary shaft 15 so as to be slidable in addition to being slidable in the axial direction of the rotary shaft 15 by sliding the guide pin 19 with respect to the guide hole 20. A thrust bearing 21 is provided on the front inner wall of the front housing 12, and the rotary support 16 is supported by the thrust bearing 21.

  A plurality of cylinder bores 22 formed around the rotation shaft 15 are arranged in the cylinder block 11, and pistons 23 are slidably accommodated in the individual cylinder bores 22. The front end of each piston 23 is engaged with the outer periphery of the swash plate 17 via a shoe 24. When the swash plate 17 rotates in conjunction with the rotary shaft 15, each piston 23 moves inside the cylinder bore 22 via the shoe 24. Move back and forth.

A suction chamber 26 is formed in the center of the rear housing 13 so as to face a valve forming body 25 including a suction valve and a discharge valve, and a discharge chamber 27 is formed on the outer peripheral side of the suction chamber 26 so as to surround the suction chamber 26. Is formed. The suction chamber 26 and the discharge chamber 27 are separated by a partition wall 13a.
In the cylinder block 11 and the rear housing 13, a communication path 28 that connects the crank chamber 14 and the discharge chamber 27 is formed, and a capacity control valve 29 that is an electromagnetic valve is disposed in the communication path 28. Further, the cylinder block 11 is formed with an extraction passage 30 that communicates the crank chamber 14 and the suction chamber 26.

The rear housing 13 is formed with a suction port 31 exposed to the outside and connected to an external refrigerant circuit. The suction port 31 and the suction chamber 26 are communicated with each other through a suction passage 32. The suction passage 32 corresponds to a flow passage constituting the piping system of the present invention. A control valve 40 for adjusting the opening degree of the suction passage 32 is disposed in the middle of the suction passage 32.
As shown in detail in FIGS. 2 and 3, the cylindrical valve housing 41 that serves as a base of the control valve 40 is made of a resin material and has a housing upper part 42 and a housing lower part 43. For convenience of explanation, the housing upper part 42 side is the upper side of the control valve 40 and the housing lower part 43 side is the lower side.

  The housing upper part 42 is set so as to have a larger diameter than the housing lower part 43 in both inner and outer diameters, and an opening 44 connected to the suction passage 32 on the side communicating with the suction chamber 26 is formed on the side surface of the housing upper part 42. ing. The inner and outer diameters of the housing upper part 42 and the housing lower part 43 can be arbitrarily set in consideration of the housing shape and the like. Further, a hole 45 a having a smaller diameter than the opening 44 is formed on the upper side surface of the housing lower portion 43, and is connected to a communication passage 59 communicating with the suction chamber 26.

  A bottomed cylindrical spool valve 50 disposed upside down is accommodated inside the housing upper part 42 so as to be slidable in the vertical direction, and its bottom 51a faces the suction passage 32 on the suction port 31 side. A flow hole 52 that always communicates with the suction passage 32 on the suction port 31 side is formed in the bottom 51a of the spool valve 50, and a side wall 51b extends downward from the outer edge of the bottom 51a. Therefore, when the spool valve 50 moves to the uppermost position of the valve housing 41 at the minimum flow rate of the refrigerant gas at the suction port 31, the side wall 51b completely closes the opening 44. Further, the side wall 51b completely opens the opening 44 when the spool valve 50 moves to the lowest position of the valve housing 41 at the maximum flow rate of the refrigerant gas at the suction port.

  A cylindrical cap 53 corresponding to the inner diameter of the housing upper part 42 is mounted above the housing upper part 42 by, for example, press fitting. A flange formed at the upper opening end of the cylindrical cap 53 is locked to the step portion of the suction passage 32 on the suction port 31 side and the upper opening end of the housing upper part 42. The lower end of the cylindrical cap 53 constitutes a stopper that contacts when the spool valve 50 moves to the uppermost position. An annular protrusion 45 formed inside the connecting portion between the housing upper portion 42 and the housing lower portion 43 constitutes a stopper that contacts when the spool valve 50 moves to the lowest position.

  A bottomed cylindrical back pressure valve 55 disposed facing the spool valve 50 is accommodated inside the housing lower portion 43 so as to be slidable in the vertical direction. The back pressure valve 55 has a bottom portion 56 and a side wall 57 extending upward from the outer edge of the bottom portion 56. Further, a compression spring 54 is interposed in a damper chamber 58 formed between the back pressure valve 55 and the spool valve 50, and urges the spool valve 50 and the back pressure valve 55 in a direction to separate them. A stepped portion 48 is formed at the lower opening end of the housing lower portion 43 by an enlarged diameter portion 46 having an enlarged inner diameter. An annular groove 47 is formed on the inner periphery of the enlarged diameter portion 46.

The bottomed cylindrical valve seat 60 includes a seat portion 61 having a through hole 62 formed in the center thereof, and a cylindrical peripheral wall 63 extending upward from the outer peripheral edge of the seat portion 61. The length of the peripheral wall 63 in the vertical direction is set shorter than the length of the side wall 57 of the back pressure valve 55. Further, a protrusion 64 is provided on the outer periphery of the peripheral wall 63. If the peripheral wall 63 is made of an elastically deformable material, the protrusion 64 can be formed over the entire periphery of the peripheral wall 63. The valve seat 60 configured as described above is attached to the enlarged diameter portion 46 with the upper end of the peripheral wall 63 in contact with the stepped portion 48 and the protrusion 64 fitted in the groove portion 47.
Therefore, when the back pressure valve 55 moves to the uppermost position, the movement of the back pressure valve 55 is restricted by contacting the lower surface of the annular protrusion 45 of the valve housing 41. In this state, the side wall 57 of the back pressure valve 55 completely closes the hole 45a. Further, when the back pressure valve 55 moves to the lowest position, the movement is restricted by contacting the upper surface of the seat portion 61 of the valve seat 60.

  The inner diameter of the peripheral wall 63 of the valve seat 60 is set slightly larger than the inner diameter of the housing lower portion 43. For this reason, when the back pressure valve 55 is in a position in contact with the seat portion 61, a gap G is generated between the outer periphery of the side wall 57 of the back pressure valve 55 and the inner periphery of the peripheral wall 63 of the valve seat 60. The gap G has a function of removing foreign matters such as dust that have entered the sliding surfaces of the back pressure valve 55 and the housing lower portion 43 and making it difficult to enter the sliding surfaces.

  When the valve housing 41 containing the spool valve 50 and the back pressure valve 55 and having the valve seat 60 attached to the lower end is mounted on the rear housing 13, the opening 44 is connected to the suction passage 32 on the suction chamber 26 side, and a hole is formed. 45 a is connected to the communication passage 59. The through hole 62 is connected to the branch path 33 communicating with the crank chamber 14 via the communication path 28.

  An annular groove 49 is provided on the outer periphery of the housing lower portion 43, which is slightly above the enlarged diameter portion 46, and an O-ring 65 is mounted in the annular groove 49. The O-ring 65 prevents the refrigerant gas from leaking to the suction chamber 26 side or the crank chamber 14 side through between the rear housing 13 and the outer periphery of the valve housing 41.

  With the above configuration, the spool valve 50 and the back pressure valve 55 are urged away from each other by the compression spring 54, and the spool valve 50 receives the suction side pressure Ps by the refrigerant gas supplied from the external refrigerant circuit, and receives the back pressure valve. 55 receives the crank chamber pressure Pc by the refrigerant gas in the crank chamber 14. Therefore, the control valve 40 is controlled to move in the vertical direction by the differential pressure between the suction side pressure Ps and the crank chamber pressure Pc. For example, during high flow operation, the back pressure valve 55 is lowered via the spool valve 50 and the compression spring 54, and the control valve 40 opens the opening 44 and the vent hole 45a (see FIG. 3). Conversely, during low flow operation, the spool valve 50 rises via the back pressure valve 55 and the compression spring 54, and the control valve 40 closes part of the opening 44 to increase the flow of refrigerant gas in the suction passage 32. While narrowing down, the vent hole 45a is also gradually closed to restrict the movement of the refrigerant gas in the damper chamber 58, thereby improving the throttling effect at the opening 44 (see FIG. 2).

  In the configuration of the present embodiment, the frequency in a specific pulsation having the greatest influence among the suction pulsations generated during low flow rate operation is selected, and the positions of the spool valve 50 and the back pressure valve 55 when the suction pulsations are generated at this specific frequency. The relationship is measured experimentally. The volume of the damper chamber 58 is calculated from the measurement result, and the cross-sectional area and length (suction) of the flow hole 52 are satisfied so as to satisfy the following formula 1 representing the principle of the Helmholtz resonator based on the selected frequency and the calculated volume. The length from the passage 32 side to the damper chamber 58) is set.

Here, f is the resonance frequency, c is the speed of sound (350 m / s 20 ° C.), S is the cross-sectional area of the flow hole 52, L is the length of the flow hole 52, and V is the volume of the damper chamber 58. For example, when the specific frequency is set to 400 Hz and the positional relationship between the spool valve 50 and the back pressure valve 55 when the suction pulsation occurs at 400 Hz is experimentally measured, the volume of the damper chamber 58 is 2800 mm ³ . When the cross-sectional area and the length of the flow hole 52 are set so as to satisfy the above formula 1 based on the specific frequency of 400 Hz and the volume of the damper chamber 58 of 2800 mm ³ , the cross-sectional area of the flow hole 52 is 0.785 mm ^2. (Corresponding to Φ1), the length of the flow hole 52 was 1 mm. The speed of sound c was set to 150 m / s based on the temperature of the suction refrigerant. By setting in this way, a Helmholtz resonance effect is nurtured in the damper chamber 58 when a pulsation of a specific frequency of 400 Hz is generated.

Further, the operation positions of the spool valve 50, the compression spring 54, and the back pressure valve 55 are set so that the side wall 57 of the back pressure valve 55 completely closes the extraction hole 45a when the suction pulsation of the specific frequency occurs. .
Therefore, when suction pulsation of a specific frequency occurs during low flow rate operation such as when the variable capacity compressor is started or during variable capacity operation, the flow hole 52 and the damper chamber 58 nurture the Helmholtz resonance effect and generate resonance vibration. , To attenuate the suction pulsation of a specific frequency.

Next, the operation of the first embodiment will be described.
Based on the reciprocating motion of the piston 23 accompanying the rotational motion of the rotating shaft 15, the refrigerant gas in the suction chamber 26 is introduced into the cylinder bore 22 by opening the suction valve of the valve forming body 25, and the refrigerant gas compressed in the cylinder bore 22 is The discharge valve is opened and discharged into the discharge chamber 27. The high-pressure refrigerant gas in the discharge chamber 27 is guided to an external refrigerant circuit (not shown).

  The capacity control valve 29 changes the amount of refrigerant gas introduced into the crank chamber 14 from the discharge chamber 27 through the communication passage 28 and the suction passage 26 from the crank chamber 14 through the extraction passage 30 by changing the opening of the valve. The balance with the amount of refrigerant gas to be derived is controlled. Accordingly, the crank chamber pressure Pc is determined by balance control of the refrigerant gas amount in the crank chamber 14. When the crank chamber pressure Pc changes, the differential pressure between the crank chamber 14 and the cylinder bore 22 is changed via the piston 23, and the inclination angle of the swash plate 17 changes. For this reason, the stroke of the piston 23 is changed, and the discharge capacity of the variable capacity compressor is changed.

  For example, in the process from the closed state of the capacity control valve 29 to the fully open state, the inclination angle of the swash plate 17 gradually decreases, and the discharge capacity is decreased to perform variable capacity operation. Thereafter, when the inclination angle of the swash plate 17 reaches the minimum state, the minimum capacity operation (OFF operation) is performed. The control valve 40 operates following the opening / closing operation of the capacity control valve 29.

  That is, in the low capacity operation such as the variable capacity operation and the minimum capacity operation, the back pressure valve 55 rises. The back pressure valve 55 is lifted by pushing up the spool valve 50 in the direction to close the opening 44 due to the biasing force of the compression spring 54 and the pressure difference between the suction side pressure Ps and the pressure in the damper chamber 58, and finally the opening. The part 44 is closed by the spool valve 50. When a part of the opening 44 is closed, a throttle corresponding to the flow rate of the refrigerant gas on the suction passage 32 side is provided, and this throttling effect causes propagation of suction pulsation due to self-excited vibration of the suction valve of the suction chamber 26. Is prevented.

  Further, when the suction pulsation of the specific frequency is generated, the vent hole 45a is closed by the back pressure valve 55 (see FIG. 2). Since the circulation hole 52 is in communication with the suction passage 32 on the suction port 31 side, the damper chamber 58 resonates due to the suction pulsation propagated to the suction passage 32, thereby creating a Helmholtz resonance effect. As a result, the suction pulsation of a specific frequency is attenuated and the propagation of the suction pulsation to the outside is prevented. The attenuation of the suction pulsation at a specific frequency also has an effect of suppressing the suction pulsation at frequencies before and after that to some extent, and a great effect of reducing the suction pulsation can be obtained by synergy with the throttling effect.

  Next, in the process of closing the capacity control valve 29 from the fully open state, the inclination angle of the swash plate 17 gradually increases, the discharge capacity increases, and the maximum capacity operation is performed. In this process, the spool valve 50 is pushed down by the suction side pressure Ps, and the back pressure valve 55 is also lowered via the compression spring 54. Therefore, the refrigerant gas in the damper chamber 58 easily flows into the suction chamber 26 due to the full opening of the vent hole 45a, the spool valve 50 is quickly lowered, and the opening 44 is fully opened at an early stage. The driving efficiency at the time can be ensured.

  When the back pressure valve 55 is lowered to the lowest position, the back pressure valve 55 comes into contact with the seat portion 61 of the valve seat 60 as shown in FIG. Even if foreign matter such as dust enters between the housing lower portion 43 and the back pressure valve 55, these dust can be removed by the presence of the gap G.

The first embodiment has the following effects.
(1) Using the damper chamber 58 of the control valve 40 conventionally used for reducing the suction pulsation, the pulsation of a specific frequency is selected from the suction pulsations generated during the low-capacity operation. Suction pulsation can be greatly reduced with a simple configuration in which the control valve 40 is formed by setting the cross-sectional area and length of the flow hole 52 based on the volume of the damper chamber 58.
(2) In the low flow rate operation, the damper chamber 58 becomes a sealed space in which only the flow hole 52 communicates with the suction passage 32 when suction pulsation of a specific frequency is generated, and the Helmholtz resonance effect can be nurtured in the damper chamber 58. Inhalation pulsation at a specific frequency can be attenuated.

(3) The attenuation of the suction pulsation of a specific frequency also affects the suction pulsation of the frequency before and after that, and can be attenuated. Therefore, it is possible to reduce the entire intake pulsation that affects the outside.
(4) The synergistic effect of the throttling effect by partially closing the opening 44 and the Helmholtz resonance effect of the damper chamber 58 can greatly contribute to the reduction of suction pulsation.

The present invention is not limited to the first embodiment described above, and various modifications can be made within the scope of the gist of the invention.
(1) In the first embodiment, it has been described that the back pressure valve 55 completely seals the vent hole 45a during the low flow rate operation and nurtures the Helmholtz resonance effect in the damper chamber 58. However, the vent hole 45a is partially opened. Alternatively, it can be carried out even in a fully opened state. That is, since the suction chamber 26 is almost hermetically sealed even when the vent hole 45a is open, when the volume V of the damper chamber 58 is calculated, the suction chamber 26, the communication passage 59, and the vent hole 45a are added in volume. What is necessary is just to set the cross-sectional area and length of the hole 52. FIG.

(2) The embodiment shown in FIGS. 4 and 5 can be employed. In this embodiment, the arrangement position of the hole 45a in the first embodiment is changed. Accordingly, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
The extraction hole 66 is disposed at a position of an annular protrusion 45 formed at a connection portion between the housing upper portion 42 and the housing lower portion 43, and is connected to a communication passage 59 communicating with the suction chamber 26. During operation of the variable capacity compressor, when the spool valve 50 is lowered by the suction side pressure Ps, the refrigerant gas in the damper chamber 58 is released to the suction chamber 26 side and the spool valve 50 is moved quickly. Is the same as that of the first embodiment. However, the hole 66 of this embodiment is different from the hole 45a of the first embodiment in that it is always open regardless of the vertical movement of the spool valve 50 and the back pressure valve 55.
In the present embodiment, in order to nurture the Helmholtz resonance effect in the damper chamber 58, the positional relationship between the spool valve 50 and the back pressure valve 55 at the time of occurrence of suction pulsation at a specific frequency during low-capacity operation is experimentally measured. The volume of the damper chamber 58 is calculated. In this case, the volume of the damper chamber 58 may be a total volume obtained by adding the volumes of the hole 66, the communication passage 59, and the suction chamber 26. Based on the specific frequency thus obtained and the volume of the damper chamber 58, the Helmholtz resonance effect can be obtained by setting the cross-sectional area S and the length L of the flow hole 52 so as to satisfy Equation 1 above. As in the first embodiment, the suction pulsation during the low-capacity operation can be reduced.

(3) The present invention can also be implemented on the discharge chamber 27 side.

(4) In the above embodiment, the specific frequency is set to 400 Hz, but may be set to a specific frequency other than 400 Hz. However, as a result of an experiment using an actual machine that does not satisfy the above formula 1, since the suction pulsation increased in the range of the specific frequency between 200 Hz and 600 Hz, it is preferable to set the specific frequency within the above range. In the above embodiment, the sound velocity set based on the volume of the damper chamber 58, the cross-sectional area and length of the inflow hole 52, and the temperature of the suction refrigerant similarly satisfies at least the above formula 1. Any value is acceptable.

It is a side view which fractures | ruptures and shows the variable capacity compressor in 1st Embodiment. It is an expanded sectional view showing a control valve at the time of low capacity operation in a 1st embodiment. It is an expanded sectional view showing a control valve at the time of maximum capacity operation in a 1st embodiment. It is sectional drawing which shows the rear housing side in other embodiment. It is an expanded sectional view showing a control valve at the time of low capacity operation in other embodiments.

Explanation of symbols

11 Cylinder block 13 Rear housing 15 Rotating shaft 17 Swash plate 23 Piston 26 Suction chamber 29 Capacity control valve 31 Suction port 32 Suction passage 33 Branch path 40 Control valve 42 Housing upper part 43 Housing lower part 44 Opening parts 45a, 66 Extract hole 50 Spool valve 52 Flowing hole 54 Compression spring 55 Back pressure valve 58 Damper chamber G Gap

Claims (3)

A crank chamber provided with a piston reciprocating mechanism, a suction chamber for supplying refrigerant gas into the cylinder bore, and a discharge chamber for discharging compressed refrigerant gas in the cylinder bore, and the refrigerant gas is controlled by pressure control of the crank chamber. A variable capacity that suppresses pulsation by changing the discharge capacity and controlling the flow of the refrigerant gas by disposing a control valve composed of at least a spool valve and a damper chamber in a piping system that forms the refrigerant gas flow passage. In the compressor, the refrigerant gas acting on the spool valve is circulated into the damper chamber through the flow hole, and the specific frequency in the pulsation that generates the cross-sectional area and the length of the flow hole and the damper at the specific frequency The volume is set based on the volume of the chamber, and the Helmholtz resonance effect is nurtured in the damper chamber when the pulsation of the specific frequency occurs. Ripple reducing device of the variable displacement compressor to. The control valve is disposed in a suction passage which is a refrigerant gas flow passage to the suction chamber, and is disposed to face the spool valve that is displaced by the pressure of the refrigerant gas and the spool valve. And a back pressure valve that is displaced upon receiving, the spool valve, the damper chamber formed between the back pressure valve and a compression spring provided in the damper chamber,
Forming a circulation hole for the refrigerant gas in the spool valve;
A hole that communicates with the suction chamber is connected to the damper chamber;
A specific frequency in the pulsation that generates a cross-sectional area and a length of the flow hole, and the damper chamber, the suction chamber, the vent hole, and the communication passage connecting the suction chamber and the vent hole at the specific frequency. The pulsation reducing device for a variable capacity compressor according to claim 1, wherein the pulsation reducing device is set based on a volume obtained by adding a value. The vent hole connected to the damper chamber is disposed in the movement path of the back pressure valve, and the opening amount of the vent hole can be changed between a fully closed state and a fully open state depending on the movement position of the back pressure valve. The pulsation reducing device for a variable capacity compressor according to claim 2.

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