WO2017163826A1

WO2017163826A1 - Scroll-type compressor

Info

Publication number: WO2017163826A1
Application number: PCT/JP2017/008631
Authority: WO
Inventors: 泰造佐藤
Original assignee: サンデン・オートモーティブコンポーネント株式会社
Priority date: 2016-03-25
Filing date: 2017-02-24
Publication date: 2017-09-28
Also published as: CN108834423A; CN108834423B; JP2017172542A; DE112017001535T5; DE112017001535B4; JP6738176B2

Abstract

In order to suppress reduction in pressure inside a back pressure chamber following the opening action of a back pressure adjustment valve, this scroll-type compressor 100 comprises: a scroll unit 1; a back pressure chamber H3 connected to a discharge chamber H2 via a pressure supply passage L3; and a back pressure adjustment valve 50 provided in a pressure release passage L4. A first throttling section T1 is provided in the pressure supply passage L3 and a second throttling section T2 is provided in the pressure release passage L4. The back pressure adjustment valve 50 is provided in the pressure release passage L4 and operates in the open-valve direction if the pressure difference between the back pressure chamber pressure P_m and the pressure P_S in an intake chamber exceeds a prescribed pressure difference P_v. The second throttling section T2 has a cross-sectional area A_out that is larger than the cross-sectional area A_in of the first throttling section T1 and smaller than the cross-sectional area A_v1 of the valve-side opening of a fluid entry hole 56 in the back pressure adjustment valve 50.

Description

Scroll compressor

The present invention relates to a scroll compressor that has a fixed scroll and a movable scroll and compresses a fluid such as a refrigerant flowing into a space between both scrolls.

This type of scroll compressor includes a scroll unit having a fixed scroll and a movable scroll. For example, the scroll compressor is incorporated in a refrigerant circuit of a vehicle air conditioner and used to compress the refrigerant in the refrigerant circuit. In this scroll unit, the movable scroll is revolved around the axis of the fixed scroll through the dynamic shaft, thereby gradually reducing the volume of the sealed space between the two scrolls, and the refrigerant gas flowing into the suction chamber Or the like is compressed in a sealed space, and the compressed fluid is discharged through a discharge chamber.
As this type of scroll compressor, for example, a scroll compressor described in Patent Document 1 is known. The scroll compressor described in Patent Document 1 has a back pressure chamber on the back side of the movable scroll. The back pressure chamber communicates with the high pressure region of the compressor through the pressure supply passage, and communicates with the low pressure region of the compressor through the pressure relief passage. The pressure in the back pressure chamber is adjusted to be a predetermined pressure intermediate between the pressure in the suction chamber and the pressure in the discharge chamber by a differential pressure actuated back pressure regulating valve provided in the pressure relief passage. The scroll compressor causes the movable scroll to revolve with respect to the fixed scroll while pressing the movable scroll against the fixed scroll by the pressure in the back pressure chamber. Therefore, in this scroll compressor, it is possible to suppress the movable scroll from moving away from the fixed scroll during the compression operation, and as a result, it is possible to prevent the occurrence of poor compression.

JP 2013-148043 A

However, in the scroll compressor described in Patent Document 1, when the back pressure adjustment valve is opened, refrigerant (refrigerant gas) or the like in the back pressure chamber suddenly flows out, and as a result, There is a risk that the pressure in the back pressure chamber will decrease more than expected. That is, the pressure in the back pressure chamber may become unstable immediately after the back pressure adjustment valve is opened. Such a phenomenon is likely to occur when a carbon dioxide refrigerant is employed as the refrigerant.
The present invention has been made paying attention to such a situation, and provides a scroll compressor capable of suppressing a decrease in the pressure in the back pressure chamber due to the opening operation of the back pressure regulating valve. Objective.

A scroll compressor according to one aspect of the present invention has a fixed scroll and a movable scroll, compresses a fluid that flows in through a suction chamber, and discharges the compressed fluid through a discharge chamber; A back pressure chamber that is formed facing the back side of the movable scroll and communicates with the discharge chamber via a pressure supply passage, and a pressure release that communicates the back pressure chamber and the suction chamber side region of the scroll unit. A differential pressure actuated back pressure regulating valve that is provided in the passage and regulates the pressure in the back pressure chamber. The scroll compressor includes a first throttle portion provided in the pressure supply passage and a second throttle portion provided in the pressure release passage. The back pressure adjusting valve is provided in a portion closer to the suction chamber than the second throttle portion in the pressure release passage, and includes a valve body, a valve seat portion that contacts and separates the valve body, and the valve seat portion. A fluid inlet hole formed and opened and closed by the valve body. The back pressure adjusting valve moves the valve body in a valve opening direction when the differential pressure between the back pressure chamber pressure and the suction chamber pressure exceeds a predetermined differential pressure, and the differential pressure is the predetermined differential pressure. In the following cases, the valve body is configured to move in the valve closing direction. The second throttle part has a cross-sectional area larger than the cross-sectional area of the first throttle part and smaller than the cross-sectional area of the valve body side opening of the fluid inlet hole.

In the scroll compressor according to the one aspect, the throttle parts (first throttle part and 2 apertures) are provided. The cross-sectional area of the second throttle portion is set to be larger than the cross-sectional area of the first throttle portion and smaller than the cross-sectional area of the valve body side opening of the fluid inlet hole. As described above, the second throttle portion, which is a throttle portion that restricts the flow of fluid by being throttled from the fluid inlet hole of the back pressure regulating valve, is provided on the upstream side of the fluid inlet hole. Therefore, even if the fluid inlet hole of the back pressure regulating valve is in an open state, it is possible to suppress the outflow of fluid from the back pressure chamber by the second throttle portion. In other words, even if the back pressure adjustment valve is opened, the second throttle portion prevents the fluid from flowing out, so that the amount of decrease in the back pressure chamber pressure can be reduced, and as a result, the back pressure chamber pressure is stabilized. Can be made.
In this way, it is possible to provide a scroll compressor that can suppress a decrease in the pressure in the back pressure chamber accompanying the opening operation of the back pressure regulating valve.

It is a schematic sectional drawing of the scroll compressor by one Embodiment of this invention. It is a block diagram for demonstrating the refrigerant | coolant flow in the said scroll compressor. It is principal part sectional drawing which showed the principal part of the said scroll compressor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of a scroll compressor according to this embodiment.
The scroll compressor 100 according to the present embodiment is incorporated in, for example, a refrigerant circuit (also referred to as a refrigeration circuit) of a vehicle air conditioner, and compresses refrigerant (fluid) sucked from a low pressure side (evaporator side) of the refrigerant circuit. To be discharged. The scroll compressor 100 includes a scroll unit 1, a housing 10 having a refrigerant suction chamber H 1 and a discharge chamber H 2 therein, an electric motor 20 that drives the scroll unit 1, and one end of a drive shaft 21 of the electric motor 20. The bearing holding part 30 for supporting a part (upper end part in FIG. 1) so that rotation is possible, and the inverter 40 for drive control of the electric motor 20 are provided. In the present embodiment, a carbon dioxide refrigerant (CO ₂ refrigerant) is adopted as the refrigerant, and the vehicle is cooled by the refrigerant circuit. Further, the scroll compressor 100 will be described by taking a so-called inverter integrated type as an example.
The scroll unit 1 includes a fixed scroll 2 and a movable scroll 3 that are meshed with each other. The fixed scroll 2 has a disk-shaped bottom plate 2a and a spiral wrap 2b integrally formed on the bottom plate 2a. The movable scroll 3 has a disk-shaped bottom plate 3a and a spiral wrap 3b integrally formed on the bottom plate 3a.
Both scrolls 2 and 3 are arranged so that both the spiral wraps 2b and 3b mesh. Specifically, both the

scrolls

2 and 3 have a predetermined gap between the end of the protruding side of the spiral wrap 2 b of the fixed scroll 2 and the bottom plate 3 a of the movable scroll 3 so that the spiral wrap 3 b of the movable scroll 3 protrudes. The side edge is disposed so as to have a predetermined gap with the bottom plate 2 a of the fixed scroll 2. This gap that can fluctuate during the compression operation is maintained in an appropriate range during the compression operation, and as a result, the airtightness of the sealed space (compression chamber) S described later is appropriately maintained.
The

scrolls

2 and 3 are arranged so that the side walls of the spiral wraps 2b and 3b are partially in contact with each other with the circumferential angles of the spiral wraps 2b and 3b shifted from each other. Thereby, a crescent-shaped sealed space (compression chamber) S is formed between the spiral wraps 2b and 3b.
The fixed scroll 2 is fixed to a rear housing 12 (to be described later) of the housing 10, and has a groove 2a1 that opens toward the rear housing 12 at the radial center. Specifically, the groove 2a1 is formed on the back surface of the bottom plate 2a (that is, the end surface opposite to the movable scroll 3).
The movable scroll 3 is configured to be capable of revolving orbiting around the axis of the fixed scroll 2 via the drive shaft 21 in a state in which the rotation is prevented. Thereby, the scroll unit 1 moves the sealed space S formed between the

scrolls

2 and 3, more specifically between the spiral wraps 2b and 3b, to the center, and gradually reduces the volume. As a result, the scroll unit 1 compresses the refrigerant flowing into the sealed space S from the outer end side of the spiral wraps 2b and 3b in the sealed space S.
As shown in FIG. 1, the housing 10 includes a front housing 11 that houses the scroll unit 1, the electric motor 20, the bearing holding portion 30, and the inverter 40, a rear housing 12, and an inverter cover 13. . The housing 10 is configured by integrally fastening the front housing 11, the rear housing 12, and the inverter cover 13 by fastening means such as bolts 14.
The front housing 11 has a substantially annular peripheral wall portion 11a and a partition wall portion 11b. The internal space of the front housing 11 is partitioned by the partition wall portion 11 b into an accommodation space for accommodating the scroll unit 1, the electric motor 20, and the bearing holding portion 30 and an accommodation space for accommodating the inverter 40. The opening on one end side (upper side in FIG. 1) of the peripheral wall portion 11 a is closed by the rear housing 12. Further, the opening on the other end side (the lower side in FIG. 1) of the peripheral wall portion 11 a is closed by the inverter cover 13. A cylindrical support portion 11b1 that holds a bearing 15 that supports the other end portion (the lower end portion in FIG. 1) of the drive shaft 21 protrudes from the radial center portion of the partition wall portion 11b.
A refrigerant suction port P1 is formed in the peripheral wall portion 11a. Refrigerant from the low pressure side (evaporator side) of the refrigerant circuit is sucked into the front housing 11 through the suction port P1. Therefore, the space in the front housing 11 functions as the suction chamber H1. Note that the refrigerant flows around the electric motor 20 and the like in the suction chamber H1. In FIG. 1, the upper space of the electric motor 20 communicates with the lower space of the electric motor 20 and constitutes one suction chamber H 1 together with the lower space of the electric motor 20. In the suction chamber H1, the refrigerant flows as a mixed fluid with a small amount of lubricating oil.
The rear housing 12 is formed in a disc shape, and its peripheral portion is fastened to one end side end portion (upper end portion in FIG. 1) of the peripheral wall portion 11a by fastening means such as a bolt 14 or the like.
Further, a peripheral edge portion (in other words, a portion surrounding the groove 2 a 1) of the rear surface of the bottom plate 2 a of the fixed scroll 2 is brought into contact with one end surface of the rear housing 12. The one end face of the rear housing 12 and the groove 2a1 of the bottom plate 2a define a refrigerant discharge chamber H2. A compressed refrigerant discharge passage L2 is formed at the center of the bottom plate 2a. In the discharge chamber H2, a one-way valve (a check valve for restricting the flow from the discharge chamber H2 to the scroll unit 1) 16 is provided so as to cover the opening of the discharge passage L2. In the discharge chamber H2, the refrigerant compressed in the sealed space S formed between the spiral wraps 2b and 3b is discharged through the discharge passage L2 and the one-way valve 16. Further, the rear housing 12 is formed with a discharge port P2 that communicates the discharge chamber H2 with the high-pressure side (that is, the condenser) of the refrigerant circuit. The compressed refrigerant in the discharge chamber H2 is discharged to the high pressure side of the refrigerant circuit through the discharge port P2.
Although illustration is omitted, for example, an appropriate oil separator for separating the lubricating oil from the compressed refrigerant flowing into the discharge port P2 is provided in the discharge port P2. The refrigerant from which the lubricating oil is separated by the oil separator (including the refrigerant in which a small amount of lubricating oil remains) is discharged to the high pressure side of the refrigerant circuit via the discharge port P2. On the other hand, the lubricating oil separated by the oil separator is guided to a pressure supply passage L3, which will be described later, in a state where a compressed refrigerant is appropriately contained, for example.
The electric motor 20 includes a drive shaft 21, a rotor 22, and a stator core unit 23 disposed on the radially outer side of the rotor 22. For example, a three-phase AC motor is applied. For example, a direct current from a vehicle battery (not shown) is converted into an alternating current by the inverter 40 and supplied to the electric motor 20.
The drive shaft 21 is connected to the movable scroll 3 via a crank mechanism, and transmits the rotational force of the electric motor 20 to the movable scroll 3. One end portion of the drive shaft 21 (that is, the end portion on the movable scroll 3 side) is rotatably supported by the bearing 17 through a through hole formed in the bearing holding portion 30. On the other hand, the other end portion (the end portion on the inverter 40 side) of the drive shaft 21 is rotatably supported by a bearing 15 fitted to the support portion 11b1.
The rotor 22 is rotatably supported on the radially inner side of the stator core unit 23 via a drive shaft 21 that is fitted (for example, press-fitted) into a shaft hole formed at the radial center thereof. When a magnetic field is generated in the stator core unit 23 by power feeding from the inverter 40, a rotational force is applied to the rotor 22 and the drive shaft 21 is rotationally driven.
The bearing holding portion 30 is provided in the front housing 11 and holds the bearing 17 that rotatably supports the end portion of the drive shaft 21 on the movable scroll 3 side. The bearing holding portion 30 is fastened integrally with the fixed scroll 2 and the rear housing 12 by fastening bolts 14 with the fixed scroll 2 sandwiched between the bearing holding portion 30 and the rear housing 12.
Specifically, the bearing holding part 30 is formed in, for example, a bottomed cylindrical shape, and includes a cylindrical part 30a and a bottom wall part 30b located on one end side of the cylindrical part 30a. The cylindrical portion 30a has a shoulder portion 30a3 that is expanded so that the inner diameter on the opening side is larger than the inner diameter on the bottom wall portion 30b side, and connects between the large-diameter portion 30a1 and the small-diameter portion 30a2. The movable scroll 3 is accommodated in a space defined by the large-diameter portion 30a1 and the shoulder portion 30a3. The opening of the bearing holding portion 30 is closed by the fixed scroll 2. The bearing 17 is fitted into the small diameter portion 30a2 of the cylindrical portion 30a. And the through-hole for making the movable scroll 3 side edge part of the drive shaft 21 penetrate is opened in the radial direction center part of the bottom wall part 30b. An appropriate seal member 18a is provided between the bearing 17 and the bottom wall portion 30b.
An annular thrust plate 19 is disposed between the shoulder 30 a 3 of the bearing holder 30 and the bottom plate 3 a of the movable scroll 3. The shoulder 30 a 3 receives a thrust force from the movable scroll 3 through the thrust plate 19. Sealing members 18b are disposed at portions of the shoulder 30a3 and the bottom plate 3a that are in contact with the thrust plate 19, respectively.
A back pressure chamber H3 is defined between the bottom plate 3a and the small diameter portion 30a2. That is, the back pressure chamber H3 is formed so as to face the back side of the movable scroll 3 (the side opposite to the fixed scroll 2). The airtightness of the back pressure chamber H3 is ensured by the

seal members

18a and 18b.
Further, between the inner peripheral surface of the peripheral wall portion 11 a of the front housing 11 and the outer peripheral surface of the cylindrical portion 30 a of the bearing holding portion 30, there is a vicinity of the outer peripheral portion of the spiral wraps 2 b and 3 b of the suction chamber H 1 and the scroll unit 1. A fluid introduction passage L1 communicating with the space H4 is formed. The refrigerant in the suction chamber H1 (specifically, a mixed fluid of the refrigerant and a small amount of lubricating oil) is introduced into the space H4 through the fluid introduction passage L1. Since the space H4 is communicated with the suction chamber H1 by the fluid introduction passage L1, the pressure in the space H4 is equal to the pressure in the suction chamber H1 (suction chamber pressure P _s ).
In the present embodiment, the crank mechanism includes a cylindrical boss portion 25 formed to protrude from the back surface (the end surface on the back pressure chamber H3 side) of the bottom plate 3a, and a crank 26 provided on the movable scroll 3 side end portion of the drive shaft 21. And an eccentric bush 27 attached in an eccentric state, and a sliding bearing 28 fitted to the boss portion 25. The eccentric bush 27 is rotatably supported in the boss portion 25 via a slide bearing 28. A balancer weight 29 facing the centrifugal force during operation of the movable scroll 3 is attached to the end of the drive shaft 21 on the movable scroll 3 side. Although not shown, a rotation prevention mechanism for preventing the rotation of the movable scroll 3 is appropriately provided. Thus, the movable scroll 3 is configured to be capable of revolving around the axis of the fixed scroll 2 via the crank mechanism in a state in which the rotation is prevented.
FIG. 2 is a block diagram for explaining the refrigerant flow in the scroll compressor 100.
The refrigerant from the low-pressure side of the refrigerant circuit is introduced into the suction chamber H1 through the suction port P1, and then guided to the space H4 near the outer end of the scroll unit 1 through the fluid introduction passage L1. And the refrigerant | coolant in the space H4 is taken in in the sealed space S between both the spiral wraps 2b and 3b, and is compressed in this sealed space S. This compressed refrigerant (compressed refrigerant) is discharged to the discharge chamber H2 via the discharge passage L2 and the one-way valve 16, and then discharged to the high-pressure side of the refrigerant circuit from the discharge chamber H2 via the discharge port P2. The In this way, the refrigerant flowing into the space H4 through the suction port P1, the suction chamber H1, and the fluid introduction passage L1 is compressed in the sealed space S, and this compressed refrigerant is discharged into the discharge passage L2, the discharge chamber H2, and the discharge port. A scroll unit 1 is configured to discharge to the outside via P2.
Here, the scroll compressor 100 according to the present embodiment further includes a differential pressure actuated back pressure adjusting valve 50 that adjusts the pressure in the back pressure chamber H3 (back pressure chamber pressure P _m ).
In the present embodiment, the back pressure regulating valve 50 is a check valve of the differential pressure actuated, when the differential pressure between the back pressure chamber pressure P _m and the intake chamber pressure P _s exceeds a predetermined differential pressure P _v operates in the valve opening direction, when the differential pressure is equal to or less than the predetermined pressure difference P _v, actuated in the closing direction, the back pressure chamber pressure P _m the pressure in the discharge chamber H2 and (discharge chamber pressure P _d) and it adjusts to a predetermined pressure (medium pressure) between the suction chamber pressure P _s. The arrangement position, structure, and back pressure adjustment operation of the back pressure adjustment valve 50 will be described in detail later.
In the present embodiment, the scroll compressor 100 includes a pressure supply passage L3 and a pressure release passage L4 in addition to the fluid introduction passage L1 and the discharge passage L2, as shown in FIGS.
The pressure supply passage L3 is a passage for communicating the discharge chamber H2 and the back pressure chamber H3. That is, the back pressure chamber H3 communicates with the discharge chamber H2 via the pressure supply passage L3. The lubricating oil separated from the compressed refrigerant in the discharge port P2 by the oil separator (not shown) is guided into the back pressure chamber H3 through the pressure supply passage L3, and each sliding portion in the back pressure chamber H3. Used for lubrication.
In the present embodiment, specifically, the pressure supply passage L3 has one end opened to the discharge chamber H2 as a high pressure region and the other end opened to the back pressure chamber H3 via the discharge port P2. Further, the rear housing 12, the bottom plate 2 a of the fixed scroll 2, and the cylindrical portion 30 a of the bearing holding portion 30 are formed.
In the middle of the pressure supply passage L3, a first throttle portion T1 that restricts the flow of fluid flowing through the pressure supply passage L3 is provided. The first throttle portion T1 is a pore having an inner diameter smaller than that of the other portion of the pressure supply passage L3. Accordingly, the lubricating oil or the like separated from the compressed refrigerant in the discharge chamber H2 is appropriately depressurized by the first throttle portion T1, and is supplied into the back pressure chamber H3 via the pressure supply passage L3. Then, the lubricating oil or the like by being introduced into the back pressure chamber H3, back pressure chamber pressure P _m is increased via the pressure supply passage L3.
The pressure release passage L4 is a passage for communicating between the back pressure chamber H3 and the suction chamber side region (that is, the low pressure region) of the scroll unit 1.
In the present embodiment, specifically, the pressure release passage L4 passes through the small diameter portion 30a2 of the cylindrical portion 30a and extends in a direction orthogonal to the drive shaft 21. One end of the pressure relief passage L4 opens to the back pressure chamber H3, and the other end of the pressure relief passage L4 opens to the fluid introduction passage L1. That is, in this embodiment, the fluid introduction passage L1 is employed as the suction chamber side region, and the pressure release passage L4 communicates between the back pressure chamber H3 and the fluid introduction passage L1. Since one end of the fluid inlet passage L1 is open to the suction chamber H1, the pressure in the fluid inlet passage L1 is equal to the suction chamber pressure P _s.
A second throttle portion T2 that restricts the flow of fluid flowing through the pressure release passage L4 is provided in the middle of the pressure release passage L4. The second throttle portion T2 is a pore having an inner diameter smaller than that of the other part of the pressure release passage L4. The cross-sectional areas of the second throttle portion T2 and the first throttle portion T1 will be described in detail later.
Next, the arrangement position and structure of the back pressure regulating valve 50 in this embodiment will be described in detail with reference to FIGS. FIG. 3 is an enlarged cross-sectional view of a main part including the back pressure adjusting valve 50.
The back pressure adjustment valve 50 is provided in a portion of the pressure release passage L4 that is closer to the suction chamber than the second throttle portion T2 (that is, the downstream side in the flow direction of the second throttle portion T2).
Specifically, the back pressure adjusting valve 50 includes a valve housing 51, a valve seat housing 52, a valve body 53, and a biasing means 54. For example, the back end of the pressure release passage L4 is an opening end on the fluid introduction passage L1 side. And constitutes a part of the pressure release passage L4.
The valve housing 51 has a cylindrical portion 51a and a bottom wall portion 51b that closes one end of the cylindrical portion 51a, is formed in a bottomed cylindrical shape as a whole, and has a valve chamber 51c inside.
The cylindrical portion 51a and the bottom wall portion 51b are formed with fluid outlet holes 55 that open to the fluid introduction passage L1. For example, two fluid outlet holes 55 are opened in the cylindrical portion 51a and one is opened in the bottom wall portion 51b. The fluid outlet hole 55 communicates the space in the fluid introduction passage L 1 and the valve chamber 51 c in the valve housing 51. The formation position and the number of the fluid outlet holes 55 can be set as appropriate.
The valve seat housing 52 constitutes one end of the back pressure regulating valve 50 and is fitted to the opening end of the pressure release passage L4 on the fluid introduction passage L1 side. The valve seat housing 52 is formed, for example, in a bottomed cylindrical shape having an outer diameter that matches the inner diameter of the pressure release passage L4, and includes a cylindrical portion 52a and a valve seat portion 52b. One end side of the cylindrical portion 52 a is fixed to the open end side of the valve housing 51. The valve seat part 52b is located on the other end side of the cylindrical part 52a, and has a conical valve seat surface 52b1 to which the valve body 53 comes in contact with and separates from. Further, a fluid inlet hole 56 opened and closed by the valve body 53 is opened in the valve seat portion 52b. The fluid inlet hole 56 is a hole through which the space on the back pressure chamber H3 side of the pressure release passage L4 communicates with the valve chamber 51c and guides a refrigerant containing lubricating oil into the valve chamber 51c.
Further, in the present embodiment, the fluid inlet hole 56 is formed so that the portion of the end portion on the back pressure chamber H3 side is smaller in diameter than the portion on the valve chamber 51c side (valve element 53 side). In the present embodiment, a portion of the end portion of the fluid inlet hole 56 on the back pressure chamber H3 side is configured as the second throttle portion T2.
In other words, in the present embodiment, the second throttle portion T2 is formed integrally with the valve seat portion 52b at the end portion of the fluid inlet hole 56 on the back pressure chamber H3 side.
The valve body 53 opens and closes the fluid inlet hole 56, is formed in a ball shape, and is urged toward the valve seat 52 b by the urging means 54. The diameter of the valve body 53 is set to be larger than the inner diameter of the opening of the fluid inlet hole 56 on the valve body 53 side.
The biasing means 54 includes a coil spring 54a whose one end is in contact with the bottom wall 51b of the valve housing 51, and a biasing rod which is connected to the other end of the coil spring 54a and biases the valve body 53 in the valve closing direction. 54b, and is disposed in the valve chamber 51c of the valve housing 51. The predetermined differential pressure _Pv , which is the valve-opening set differential pressure of the back pressure adjusting valve 50, is a design value (set value) determined according to the spiral wrap shape of the scroll unit 1 and the like. It is set by selecting a coil spring 54a having power.
In the present embodiment, the back pressure adjusting valve 50 includes a valve housing 51, a valve seat housing 52, a fluid inlet hole 56 formed in the valve seat housing 52 and opened to the back pressure chamber H3 side of the pressure release passage L4, and a fluid A valve body 53 that opens and closes the inlet hole 56; a valve seat portion 52b that is formed in the valve seat housing 52 and contacts and separates; a biasing means 54; a fluid outlet hole 55 that opens to the fluid introduction passage L1; When the differential pressure between the back pressure chamber pressure P _m and the suction chamber pressure P _s exceeds the predetermined differential pressure P _v , the valve body 53 is moved in the valve opening direction, and the differential pressure becomes the predetermined differential pressure. When _Pv or less, the valve body 53 is configured to move in the valve closing direction.
Next, the magnitude relationship of the cross-sectional areas of the first throttle part T1, the second throttle part T2, and the fluid inlet hole 56 of the back pressure regulating valve 50 will be described.
The second throttle portion T2 is greater than the cross-sectional area _{A in} the first throttle portion T1, and has a cross-sectional area _{A v1} smaller cross-sectional area _{A out} of the valve body side opening of the fluid inlet hole 56. The total cross-sectional area A _v2 of the fluid outlet hole 55 is larger than the cross-sectional area A _v1 of the fluid inlet hole 56 (that is, A _v2 > A _v1 > A _out > A _in ). Therefore, the minimum flow passage area of the pressure passage L4 release is determined by the cross-sectional area A _out of the second aperture portion T2.
Next, the operation of adjusting the back pressure chamber pressure P _m by the back pressure adjusting valve 50 in the scroll compressor 100 will be schematically described. Incidentally, the back pressure regulating valve 50, as well as in closed state, as back pressure chamber pressure P _m is becoming higher, it will be described below. In the following description, it is assumed that the discharge chamber pressure _Pd is stable at a lower limit value (low load state) of a fluctuation range described later.
First, it is assumed that the back pressure adjusting valve 50 presses the valve element 53 against the valve seat surface 52b1 by the urging means 54 to close the opening of the fluid inlet hole 56. At this time, the valve body 53, a biasing force of the coil spring 54a of the urging means 54, the suction chamber pressure P _s traveling through the fluid inlet passage L1 and a fluid outlet hole 55 is acting. In this state, the back pressure chamber pressure P _m is gradually increased, a predetermined differential pressure P _v which pressure difference between the back pressure chamber pressure P _m and the intake chamber pressure P _s is determined based on the biasing force of the biasing means 54 When exceeding, the valve body 53 moves in the valve opening direction against the urging force of the urging means 54. When the back pressure adjusting valve 50 is opened, the refrigerant gas or the like in the back pressure chamber H3 is released to the fluid introduction passage L1 side (that is, the low pressure region side) through the pressure release passage L4. The back pressure chamber pressure P _m can be reduced. However, since the flow of the fluid such as the refrigerant gas flowing through the pressure release passage L4 is regulated by the second throttle portion T2, the outflow of the fluid such as the refrigerant gas from the back pressure chamber H3 is suppressed. The refrigerant gas or the like guided in the middle of the fluid introduction passage L1 through the back pressure adjusting valve 50 is returned to the scroll unit 1 side (space H4 side) along the flow in the fluid introduction passage L1. When the differential pressure becomes equal to or less than the predetermined differential pressure _Pv , the valve body 53 moves in the valve closing direction by the urging force of the urging means 54. Thus, the back pressure regulating valve 50, thereby boosting the back pressure chamber pressure P _m. As described above, the back pressure adjusting valve 50 has a valve opening set pressure P _c (= P _s + P _v) obtained by adding the suction chamber pressure P _s to the predetermined differential pressure P _v at a low load or immediately after the start of operation. ) as a target pressure, back pressure chamber pressure P _m is closer to the target pressure, to open and close the valve body 53.
By the way, the external environmental conditions (outside air temperature etc.) of the condenser (high pressure side) of the refrigerant circuit vary. Therefore, the heat exchange capacity of the condenser of the refrigerant circuit also varies. Accordingly, the discharge chamber pressure P _d of the scroll type compressor 100 varies by the heat exchange capacity of the condenser. In other words, the load of the scroll compressor 100 varies. On the other hand, the suction pressure of the refrigerant flowing into the scroll compressor 100 from the evaporator (low pressure side) of the refrigerant circuit is controlled to be substantially constant by the vehicle air conditioner. That is, the suction chamber pressure P _s is a set value that is set according to the required capacity of the refrigerant circuit (refrigeration circuit). As a result, the suction chamber pressure P _s is fixed to a predetermined set value. Strictly speaking, it fluctuates minutely even suction chamber pressure P _s. However, the variation width of the suction chamber pressure P _s is smaller negligibly compared to the variation range of the discharge chamber pressure P _d, the suction chamber pressure P _s can be regarded as a fixed value.
In the present embodiment employing carbon dioxide refrigerant as a refrigerant, for example, those suction chamber pressure P _s is set to 3.5 MPa, discharge chamber pressure P _d is varied in a range of 5 ~ 13 MPa during operation of the compressor And Therefore, the suction chamber pressure _{P s} is a predetermined set value (e.g., 3.5 MPa) is fixed to the discharge chamber pressure _{P d} can vary within the variation range (operating range). In this case, the scroll compressor 100 becomes lighter as the discharge chamber pressure _Pd is smaller, and becomes heavier as the discharge chamber pressure _Pd is larger. As a result, also changes in accordance with a variation in the discharge chamber pressure P _d for the optimal value of the back pressure chamber in the pressure P _m. Therefore, for example, when the valve opening set pressure P _c (= P _s + P _v ) is set low so that the back pressure does not become excessive when the load is low, the back pressure becomes insufficient when the load is high. Volumetric efficiency will be reduced. A configuration for solving this problem will be described in detail below.
In this embodiment, after the back pressure chamber pressure P _m reaches the valve opening set pressure P _c and the back pressure adjustment valve 50 is in the open state, the discharge chamber pressure P _d further increases. the valve 50 is configured to allow boosting in accordance with back pressure chamber pressure P _m to the increase in discharge chamber pressure P _d.
Specifically, in the present embodiment, first, the valve opening set pressure P _c is, for example, the discharge chamber pressure P _d within the fluctuation range of the discharge chamber pressure P _d in order to eliminate the excessive back pressure state at low load. It is preset to a value between the lower limit value and the set value of the suction chamber pressure P _s.
Further, in this embodiment, in order to eliminate the back pressure shortage state at the time of high load, the cross-sectional area A _out of the second throttle portion T2 varies when the discharge chamber pressure P _d varies within the predetermined variation range. , in this variation range, it is set so that the flow rate (mass flow rate) G _out of the fluid flowing through the second aperture portion T2 is less than the flow rate (mass flow rate) G _in the fluid flowing through the first throttle portion T1 (That is, G _in > G _out ). As a result, even if the back pressure adjustment valve 50 is opened, the amount of fluid discharged from the back pressure chamber H3 is always smaller than the amount of fluid supplied to the back pressure chamber H3. As a result, even when the back pressure regulating valve 50 is in the open state, the back pressure chamber pressure P _m varies according to the variation of the discharge chamber pressure P _d , and the back pressure chamber pressure P _m at the high load is As the pressure _Pd increases, the pressure increases.
More specifically, the G _in and the G _out satisfy the following relational expressions (1) to (3). However, (rho) d shows the density of the fluid which distribute | circulates the 1st restricting part T1, and (rho) m shows the density of the fluid which distribute | circulates the 2nd restricting part T2.
G _in > G _out (1)
G _in = A _in × {2 × (P _d −P _m ) × ρd} ^1/2 Equation (2)
_{_{G out = A out × {2}} × (P m -P s) × ρm} 1/2 ... Equation (3)
Further, ρm can be expressed by an approximate expression shown by the following expression (4).
ρm≈ρd × (P _m / P _d ) (4)
Here, the following relational expression (5) is established from the above relational expressions (1) to (4) and the relational expression of P _m = P _v + P _s .
_{_{A in / A out> {(}} P v × (P v + P s)) / ((P d - (P v + P s)) × P d)} 1/2 ... (5)
That is, in the present embodiment, when the suction chamber pressure P _s is fixed at a predetermined set value and the discharge chamber pressure P _d varies within the variation range, A _in and A _out become the discharge chamber pressure P. Within the fluctuation range of _d , it is set so as to satisfy the relationship of Expression (5).
According to the scroll compressor 100 according to the present embodiment, the pressure supply passage L3 and the pressure release passage L4 are provided with throttle portions (first throttle portion T1 and second throttle portion T2), respectively. The cross-sectional area _{A out} of the second aperture portion T2 is greater than the cross-sectional area _{A in} the first throttle portion T1, and is set to be smaller than the cross-sectional area _{A v1} of the valve body side opening of the fluid inlet hole 56 ing. Therefore, even if the fluid inlet hole 56 of the back pressure adjustment valve 50 is in the open state, the second throttling portion T2 can suppress the outflow of fluid from the back pressure chamber H3. That is, even back pressure regulating valve 50 is opened, because the outflow of the fluid is suppressed by the second throttle portion T2, it is possible to reduce the amount of reduction in back pressure chamber pressure P _m, as a result, the back pressure chamber it is possible to stabilize the pressure P _m.
In this way, it is possible to provide a back pressure chamber pressure P _m scroll compressor 100 capable of suppressing a reduction in associated with the opening operation of the back pressure regulating valve 50.
Further, in the present embodiment, the cross-sectional area _{A out} of the second aperture portion T2, in the range of variation of the discharge chamber pressure _{P d,} flow rate _{G out} of the fluid flowing through the second aperture portion T2 flows through the first throttle portion T1 It is set to be less than the flow rate G _{in of} the fluid to be used. Thus, by setting the cross-sectional area A _out of the second aperture portion T2, even back pressure regulating valve 50 was opened, during a high load, discharge chamber pressure back pressure chamber pressure P _m it can be boosted in accordance with the increase of P _d. Thus, for example, discharge chamber pressure P _d becomes higher fluctuate within the variation range (operating range), even in a high load state, it is possible to back pressure to suppress or eliminate made that insufficient.
In the present embodiment, A _in and A _out are set so as to satisfy the relationship of the above formula (5) within the fluctuation range of the discharge chamber pressure P _d . Thus, simply by preliminarily appropriately set the ratio of A _in the A _out, it is possible to reliably increase the back pressure chamber pressure P _m in the high load.
Further, in the present embodiment, the valve opening set pressure P _c (= P _v + P _s ) of the back pressure regulating valve 50 is the lower limit value (for example, 5 MPa) of the discharge chamber pressure P _{d in} the fluctuation range of the discharge chamber pressure P _d. the set value of the suction chamber pressure P _s (e.g., 3.5 MPa) is preset to an appropriate value between. In this way, by setting the valve opening set pressure _Pc , the back pressure adjusting valve 50 of the back pressure adjusting valve 50 is set so that the back pressure chamber pressure P _m becomes a substantially constant pressure lower than that at the high load at the time of low load. It can be adjusted by opening and closing operations. As a result, it is possible to suppress or eliminate the back pressure from becoming excessive at low load.
That is, in this embodiment, both the back pressure excess at the time of low load and the back pressure deficiency at the time of high load can be solved. As a result, the variation range of the discharge chamber pressure P _d (i.e., the operation range of the compressor), the mechanical efficiency and without any of the volumetric efficiency at the expense, good compression operation can be performed scroll type compression A machine 100 can be provided.
Further, in the present embodiment, the second throttle portion T2 is integrally formed with the valve seat portion 52b at a portion of the fluid inlet hole 56 at the back pressure chamber side end portion. As a result, the second throttle portion T2 can be easily formed in the downstream side portion of the pressure release passage L4. When the spherical valve body 53 is employed, the diameter of the valve body 53 is usually set so that the valve body 53 comes into contact with the corner of the valve body side opening of the fluid inlet hole 56 to be opened and closed. Therefore, if the inner diameter of the valve body side opening of the fluid inlet hole 56 is small, the diameter of the valve body 53 also needs to be reduced. In this respect, since the valve body side opening of the fluid inlet hole 56 in this embodiment is opened larger than the second throttle portion T2, the valve body 53 having a general diameter can be employed. The second throttle portion T2 may not be formed integrally with the valve seat portion 52b.
Further, in the present embodiment, it includes a fluid introduction passage L1 that connects the suction chamber H1 and the space H4 near the outer periphery of the scroll unit 1, and the pressure release passage L4 communicates the back pressure chamber H3 and the fluid introduction passage L1. is doing. Thereby, the lubricating oil that has flowed into the back pressure chamber H3 is returned to the scroll unit 1 along the flow of the fluid introduction passage L1, and the lubricity and airtightness of the sliding portion in the scroll unit 1 can be enhanced.
As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to the said embodiment, A various deformation | transformation and change are possible based on the technical idea of this invention.
For example, in this embodiment, in order to eliminate the back pressure excess state at low load, to a value between the valve opening set pressure P _c is the lower limit value of the discharge chamber pressure P _d and the set value of the suction chamber pressure P _s Although the case where it is set has been described as an example, it is not limited thereto. For example, when priority is given to improving the volumetric efficiency of the scroll compressor 100 and a reduction in mechanical efficiency is allowed, the valve opening set pressure P is set so as to reliably prevent the back pressure from becoming insufficient at high loads. You may set _c high. In this case, the wear resistance of the scroll unit 1 may be enhanced by devising the material of the contact portions of the fixed scroll 2 and the movable scroll 3.
In the present embodiment, the pressure relief passage L4 communicates the back pressure chamber H3 and the fluid introduction passage L1. That is, the fluid introduction passage L1 is adopted as the suction chamber side region of the scroll unit 1. However, the connection destination of the pressure release passage L4 is not limited to this. For example, although not shown, the suction chamber H 1 itself may be adopted as the suction chamber side region of the scroll unit 1. In this case, the pressure release passage L4 communicates the back pressure chamber H3 and the suction chamber H1.
Further, in the present embodiment, the refrigerant has been assumed to be CO ₂ refrigerant is not limited to this, it is possible to apply the appropriate refrigerant.
Further, in the present embodiment, the scroll compressor 100 has been described by taking a so-called inverter-integrated case as an example. However, the present invention is not limited to this, and the scroll compressor 100 may be separate from the inverter 40.

DESCRIPTION OF SYMBOLS 1 ... Scroll unit 2 ... Fixed scroll 3 ... Movable scroll 50 ... Back pressure regulating valve 55 ... Fluid outlet hole 56 ... Fluid inlet hole 52b ... Valve seat part 53 ... Valve body 100 ... Scroll compressor H1 ... Suction chamber H2 ... Discharge chamber H3 ... Back pressure chamber H4 ... Space L1 .... Fluid introduction passage L3 ... Pressure supply passage L4 ... Pressure release passage T1 ... First throttling portion T2 ... Second throttling portion

Claims

A scroll unit having a fixed scroll and a movable scroll, compressing fluid flowing in through the suction chamber, and discharging the compressed fluid through the discharge chamber;
A back pressure chamber formed facing the back side of the movable scroll and communicated with the discharge chamber via a pressure supply passage;
A differential pressure actuated back pressure adjustment valve that is provided in a pressure relief passage that communicates the back pressure chamber and the suction chamber side region of the scroll unit, and that adjusts the pressure in the back pressure chamber;
A scroll type compressor comprising:
A first throttle portion provided in the pressure supply passage;
A second throttle portion provided in the pressure relief passage;
Including
The back pressure adjusting valve is provided in a portion closer to the suction chamber than the second throttle portion in the pressure release passage, and includes a valve body, a valve seat portion that contacts and separates the valve body, and the valve seat portion. A fluid inlet hole formed and opened and closed by the valve body, and when the pressure difference between the back pressure chamber pressure and the suction chamber pressure exceeds a predetermined pressure difference, the valve body is opened in the valve opening direction. When the differential pressure is less than or equal to the predetermined differential pressure, the valve body is moved in the valve closing direction,
The scroll type compressor, wherein the second throttle portion has a cross-sectional area larger than a cross-sectional area of the first throttle portion and smaller than a cross-sectional area of a valve body side opening of the fluid inlet hole.
When the discharge chamber pressure fluctuates within a predetermined fluctuation range, the cross-sectional area of the second throttling portion is such that the flow rate of the fluid flowing through the second throttling portion in the fluctuation range causes the first throttling portion to The scroll compressor according to claim 1, wherein the scroll compressor is set to be smaller than a flow rate of the circulating fluid.
The cross-sectional area of the first throttle portion is A in , the cross-sectional area of the second throttle portion is A out , the suction chamber pressure is P s , the predetermined differential pressure is P v , and the discharge chamber pressure is P d, and when the P s is fixed to a predetermined set value and the P d varies within the variation range,
The scroll compressor according to claim 2, wherein the A in and the A out are set so as to satisfy a relationship of the following expression (1) within the fluctuation range of the P d .
A in / A out> {( P v × (P v + P s)) / ((P d - (P v + P s)) × P d)} 1/2 ... formula (1)
Opening set pressure obtained by adding the set value of the P s in the P v is previously set to a value between the set value of the lower limit value and the P s of the P d in the variation range The scroll compressor according to claim 3.
The scroll compressor according to any one of claims 1 to 4, wherein the second throttle portion is formed integrally with the valve seat portion at a portion of a back pressure chamber side end portion of the fluid inlet hole. .
A fluid introduction passage communicating the suction chamber and a space near the outer periphery of the scroll unit;
6. The scroll compressor according to claim 1, wherein the pressure release passage communicates the back pressure chamber and the fluid introduction passage.
6. The scroll compressor according to claim 1, wherein the pressure release passage communicates the back pressure chamber and the suction chamber.
The scroll compressor according to any one of claims 1 to 7, wherein the fluid is a carbon dioxide refrigerant.