WO2019138502A1

WO2019138502A1 - Scroll compressor

Info

Publication number: WO2019138502A1
Application number: PCT/JP2018/000491
Authority: WO
Inventors: 太樹飯塚
Original assignee: 日立ジョンソンコントロールズ空調株式会社
Priority date: 2018-01-11
Filing date: 2018-01-11
Publication date: 2019-07-18

Abstract

This scroll compressor (S) is provided with: a compression mechanism portion (3) comprising a plurality of compression chambers (51) formed by an orbiting scroll (11) and a fixed scroll (12); a bypass port (41) providing communication between inner spaces of the compression chambers and an external suction-side space; a capacity control valve (45) for switching the opening and closing of the bypass port; and a control unit (30) which performs, after the start of a compression mechanism portion stopping process, a brake control for preventing reverse rotation of the compression mechanism portion due to an input-output pressure difference.

Description

Scroll compressor

The present invention relates to a scroll compressor.

Conventionally, in a scroll compressor, compression torque is generated by a pressure difference (hereinafter referred to as “input / output pressure difference”) between the suction pressure and the discharge pressure of the compression mechanism when transitioning from an operating state to a stopped state. In some cases, the mechanism rotates in the reverse direction and an abnormal sound is generated.

Therefore, in the scroll compressor, in order to suppress the generation of abnormal noise, a structure is widely used to prevent reverse rotation of the compression mechanism at the time of stop by providing a check valve on the suction side or discharge side of the compression mechanism. Used.

However, by providing a check valve on the suction side or the discharge side of the compression mechanism portion, the scroll compressor having such a structure inhibits the flowability of the flow path of the working fluid, resulting in a decrease in compression performance, There is a problem that the number of parts increases and the cost rises.

Therefore, in relation to the scroll compressor, there has been proposed a technique for preventing reverse rotation of the compression mechanism at the time of stop by controlling the motor unit connected to the compression mechanism without using the check valve.

For example, Patent Document 1 and Patent Document 2 do not provide a check valve or the like for preventing reverse rotation of the compression mechanism portion, and a brake that prevents reverse rotation of the compression mechanism portion when stopped by electrical means. A controller is described.

Japanese Patent Laid-Open No. 2000-287485 JP-A-11-46494

However, in the conventional techniques described in Patent Document 1 and Patent Document 2, it is desired to reliably prevent reverse rotation of the compression mechanism portion at the time of stop, as described below.

For example, according to the prior art described in Patent Document 1 and Patent Document 2, under the high pressure condition where the input / output pressure difference is large, the load torque in the reverse rotation direction applied to the compression mechanism at the time of stop is rotated depending on the control timing. It has been difficult to prevent the reverse rotation of the compression mechanism because the braking torque in the stopping direction is exceeded (exceeded). Therefore, the prior art described in Patent Document 1 and Patent Document 2 can be used only for a compressor having a relatively small load torque at the time of stop, and is used for a compressor having a relatively large load torque at the time of stop I could not. That is, the prior art described in Patent Document 1 and Patent Document 2 may not be able to prevent reverse rotation of the compression mechanism portion at the time of stopping.

The present invention has been made to solve the above-described problems, and has as its main object to provide a scroll compressor that reliably prevents reverse rotation of the compression mechanism portion at the time of stop.

In order to achieve the above object, the present invention is a scroll compressor, comprising: a compression mechanism portion forming a plurality of compression chambers by a orbiting scroll and a fixed scroll; an inner space of the compression chamber and a suction side space outside Control to switch the opening and closing of the bypass port, and control for performing brake control to prevent reverse rotation of the compression mechanism section due to the input / output pressure difference after starting the stop processing of the compression mechanism section And a unit.
Other means will be described later.

According to the present invention, when the compression mechanism is stopped, reverse rotation of the compression mechanism at the time of stop can be reliably prevented.

It is a longitudinal section showing the composition of the scroll compressor concerning an embodiment. It is a flow chart which shows operation of a scroll compressor concerning an embodiment. It is a cross-sectional view which shows the structure of a turning scroll and a fixed scroll. It is a schematic diagram which shows the relationship between a base circle and an involute curve. It is a schematic diagram which shows the relationship between the tangent of a base circle, and an involute curve. It is a schematic diagram which shows the positional relationship of turning scroll wrap and fixed scroll wrap. It is a schematic diagram which shows the relationship between the action surface of suction pressure, and the imaginary surface on which all the pressure acts. It is a schematic diagram which shows the length of the virtual surface of a discharge opening periphery. It is a schematic diagram which shows the relationship between the adjacent surface of a compression chamber, and the action surface of intermediate pressure.

Hereinafter, embodiments of the present invention (hereinafter, referred to as “this embodiment”) will be described in detail with reference to the drawings. The drawings are only schematically shown to the extent that the present invention can be sufficiently understood. Therefore, the present invention is not limited to the illustrated example. Moreover, in each figure, about the component common in common, and the same component, the same code | symbol is attached | subjected and those duplicate description is abbreviate | omitted.

[Embodiment]
<Configuration of scroll compressor>
(Overall configuration of scroll compressor)
The configuration of the scroll compressor S according to the present embodiment will be described below with reference to FIG. FIG. 1 is a longitudinal sectional view showing the configuration of the scroll compressor S according to the present embodiment. In the present embodiment, the scroll compressor S is described as a vertical apparatus. The scroll compressor S can be used for air conditioners, and refrigeration cycle devices such as refrigerators and freezers in general. The scroll compressor S uses, for example, an R32 refrigerant as a working fluid.

As shown in FIG. 1, the scroll compressor S according to the present embodiment includes a controller 30 that controls the overall operation, and an open / close switching device 40 that controls the operation of a displacement control valve 45 described later. In addition, the scroll compressor S is disposed in the hermetic container 1 referred to as a “chamber”, a motor unit 2 disposed inside the hermetic container 1, and inside the hermetic container 1, and is driven by the motor unit 2 And a crankshaft 6 for transmitting the rotational power of the motor unit 2 to the compression mechanism unit 3.

The closed container 1 comprises a cylindrical cylinder chamber 1a, a lid chamber 1b welded to the upper portion of the cylinder chamber 1a, and a bottom chamber 1c welded to the lower portion of the cylinder chamber 1a. A sealed chamber internal space 54 is formed inside the sealed container 1. The chamber internal space 54 is in communication with the discharge port 5 provided in the compression mechanism section 3. When the scroll compressor S operates, the working fluid is discharged from the discharge port 5 into the chamber space 54. As a result, a relatively high discharge pressure Pd (see FIG. 3) is applied to the space 54 in the chamber. Hereinafter, the chamber internal space 54 may be referred to as “discharge pressure space”. The scroll compressor S is a so-called high pressure chamber type compressor in which the chamber internal space (discharge pressure space) 54 has a high pressure atmosphere.

A suction pipe 7 is fixed by welding or brazing on the upper surface of the lid chamber 1b. The suction pipe 7 is attached to the lid chamber 1 b so as to communicate with the suction chamber 4 provided in the compression mechanism section 3.

Further, the discharge pipe 8 is fixed by welding or brazing on the side surface of the cylinder chamber 1a. The discharge pipe 8 is attached to the cylinder chamber 1 a so as to communicate with the chamber internal space (discharge pressure space) 54. The scroll compressor S discharges the working fluid discharged from the discharge port 5 into the chamber internal space 54 to the outside of the scroll compressor S via the discharge pipe 8.

Oil (lubricating oil) is enclosed in the inside of the closed container 1 at an appropriate stage when assembling the scroll compressor S. An oil reservoir 9 is thus formed at the bottom of the closed container 1.

The motor unit 2 includes a stator 2a and a rotor 2b. The stator 2a is fixed to the closed container 1 by shrink fitting, welding or the like. The rotor 2b is rotatably disposed inside the stator 2a. A crankshaft 6 is fixed to the rotor 2b.

The crankshaft 6 is supported by a main bearing 13 a provided on a frame 13 whose upper side is described later, and the lower side is supported by a lower bearing 10. At an upper portion of the crankshaft 6, a pin portion 6c which is an eccentric portion is provided. When the motor unit 2 is driven to rotate the crankshaft 6, the pin unit 6 c performs eccentric rotational movement with respect to the main shaft of the crankshaft 6. The crankshaft 6 is provided with an oil supply vertical hole 6a and an oil supply horizontal hole 6b for supplying the oil of the oil storage portion 9 to a turning bearing portion 11c described later.

The compression mechanism unit 3 includes an orbiting scroll 11, a fixed scroll 12, a frame 13, an Oldham ring 14, and a displacement control valve 45.

The orbiting scroll 11 has an orbiting scroll wrap 11a, an orbiting end plate 11b, and an orbiting bearing portion 11c. The orbiting scroll wrap 11a is a spiral wrap formed so as to stand on the orbiting end plate 11b. The orbiting bearing portion 11 c is a bearing portion into which the pin portion 6 c which is an eccentric portion of the crankshaft 6 is inserted.

The fixed scroll 12 has a fixed scroll wrap 12a and a fixed end plate 12b. The fixed scroll wrap 12a is a spiral wrap formed to stand on the fixed end plate 12b. A suction chamber 4 is provided at an outer peripheral portion of the fixed scroll wrap 12a. Further, in the vicinity of the outer peripheral portion of the fixed scroll wrap 12a, a bypass port 41 for communicating the internal space of the compression chamber 51 with the external suction side space is provided. Moreover, the discharge port 5 is provided in the center part of fixed scroll wrap 12a. The suction chamber 4 is a space before the compression chamber 51 is formed, and is divided into an internal space of the compression chamber 51 and an external suction side space by the compression chamber 51 being formed. When the scroll compressor S operates, the suction pressure Ps (see FIG. 3), which is lower than the discharge pressure Pd (see FIG. 3), is applied to the inside of the suction chamber 4.

The orbiting scroll 11 is disposed to face the fixed scroll 12 so as to be pivotable. The compression mechanism portion 3 communicates with the suction chamber 4 between the orbiting scroll wrap 11a and the fixed scroll wrap 12a by orbiting the orbiting scroll 11 in a state where the orbiting scroll wrap 11a and the fixed scroll wrap 12a are engaged. To form a compression chamber 51.

The outer peripheral side of the frame 13 is fixed to the inner wall surface of the closed container 1 by welding. The frame 13 includes a main bearing 13 a that rotatably supports the main shaft of the crankshaft 6. The fixed scroll 12 is fastened and fixed to the frame 13 by bolts. Further, a back pressure chamber 53 is formed between the orbiting scroll 11 and the frame 13. The back pressure chamber 53 adds back pressure Pb (not shown) in the direction from the orbiting scroll 11 side to the fixed scroll 12 side to the working fluid. Thereby, the compression mechanism portion 3 presses the orbiting scroll 11 to the fixed scroll 12 side with the working fluid to which the back pressure Pb (not shown) is added so that the orbiting scroll 11 does not separate from the stationary scroll 12. The back pressure Pb (not shown) is set to a pressure substantially intermediate between the discharge pressure Pd (see FIG. 3) and the suction pressure Ps (see FIG. 3).

The Oldham ring 14 is disposed between the orbiting scroll 11 and the frame 13. The Oldham ring 14 is a rotation restricting member for causing the fixed scroll 12 to perform a turning motion without rotating the turning scroll 11. The Oldham ring 14 is provided with a key portion (not shown). The key portion is inserted into a swing oldham groove (not shown) formed in the swing scroll 11 and a frame oldham groove (not shown) formed in the frame 13. Thereby, the Oldham ring 14 regulates rotation of the orbiting scroll 11.

The controller 30 controls the operation of the motor unit 2 and controls the operation of the open / close switching device 40.

The displacement control valve 45 is a mechanism that switches the opening and closing of the bypass port 41. The open / close switching device 40 opens and closes the displacement control valve 45 in accordance with the control of the controller 30. By opening and closing the displacement control valve 45, the open / close switching device 40 temporarily communicates the internal space of the compression chamber 51 with the external suction side space via the bypass port 41, thereby allowing the input / output of the compression mechanism 3. Reduce the pressure difference (the pressure difference between the suction pressure and the discharge pressure). Hereinafter, control for opening the displacement control valve 45 is referred to as “capacity control”.

The scroll compressor S includes a coil spring 46 as an elastic body that biases the displacement control valve 45 in the opening direction. In the scroll compressor S, since the coil spring 46 biases the displacement control valve 45 in the direction to open, when the stopping process of the compression mechanism 3 is started, the displacement control valve 45 can be automatically opened.

In addition, in the conventional general scroll compressor before the prior art described in the above-mentioned patent documents 1 and patent documents 2, it is on the suction side (for example, part Ar shown in Drawing 2) or discharge side of compression mechanism part 3 The non-return valve for preventing the reverse rotation of the compression mechanism part 3 was provided. However, in the scroll compressor S according to the present embodiment, reverse rotation of the compression mechanism 3 is prevented on the suction side (the portion Ar shown in FIG. 2) of the compression mechanism 3 and also on the discharge side. There is no stop valve. That is, the scroll compressor S according to the present embodiment has a structure in which the check valve for preventing reverse rotation of the compression mechanism 3 is removed from the suction side (part Ar shown in FIG. 2) and the discharge side of the compression mechanism 3. It has become. Since the scroll compressor S according to the present embodiment can simplify the structure on the suction side and the discharge side of the compression mechanism portion 3, the number of parts can be reduced compared to a conventional general scroll compressor. Thus, the manufacturing cost can be reduced.

<Operation of scroll compressor>
The operation of the scroll compressor S according to the present embodiment will be described below with reference to FIG. FIG. 2 is a flowchart showing the operation of the scroll compressor S. The operation of the scroll compressor S is mainly performed by the controller 30.

The scroll compressor S opens the bypass port 41 at the time of stop processing of the compression mechanism portion 3 to reduce an input / output pressure difference of the compression mechanism portion 3 and then applies a brake torque to the motor portion 2 to By stopping 2, the brake control is performed to prevent reverse rotation of the compression mechanism 3.

As shown in FIG. 2, in the stopped state, the controller 30 of the scroll compressor S performs normal operation control when receiving an operation start instruction from a host system (not shown) constituting the refrigeration cycle system (step S110). As a result, the operation of the scroll compressor S shifts from the stop state to the operating state.

The controller 30 of the scroll compressor S repeatedly determines whether or not there is a stop instruction transmitted from the upper apparatus (not shown) during operation (step S120). If it is determined in step S120 that a stop instruction has not been issued (in the case of "No"), the process returns to step S110, while if it is determined that a stop instruction has been issued (in the case of "Yes") The process proceeds to step S130.

If it is determined in step S120 that a stop instruction has been issued (in the case of “Yes”), the controller 30 of the scroll compressor S starts operation stop control (step S130). Here, after the operation stop control, for example, opens the bypass port 41 to reduce the input / output pressure difference of the compression mechanism unit 3, the control to apply the brake torque to the motor unit 2 to stop the motor unit 2 It is assumed that the

When the operation stop control is started, the controller 30 of the scroll compressor S transmits, to the open / close switching device 40, an instruction to open the displacement control valve 45. In response to this, the on-off switching device 40 performs the opening control of the displacement control valve 45 (step S140). Thus, the scroll compressor S reduces the input / output pressure difference of the compression mechanism unit 3.

After step S140, the controller 30 of the scroll compressor S starts brake control to apply a brake torque to the motor unit 2 (step S150), and ends the brake control when the motor unit 2 is stopped (step S160). Thereby, scroll compressor S stops operation.

<Configuration of orbiting scroll and fixed scroll>
The configurations of the orbiting scroll 11 and the fixed scroll 12 will be described below with reference to FIG. FIG. 3 is a cross-sectional view showing the configuration of the orbiting scroll 11 and the fixed scroll 12. FIG. 3 shows the configurations of the orbiting scroll 11 and the fixed scroll 12 as viewed from below.

As shown in FIG. 3, a discharge port 5 is provided at the center of the fixed scroll wrap 12a. Moreover, the suction chamber 4 is provided in the outer peripheral part of fixed scroll wrap 12a. The scroll compressor S rotates the orbiting scroll 11 in a state in which the orbiting scroll wrap 11a and the fixed scroll wrap 12a are engaged with each other, whereby a plurality of compression chambers 51 are provided between the orbiting scroll wrap 11a and the fixed scroll wrap 12a. Form The scroll compressor S has a structure in which the nth compression chamber 51 n from the discharge port 5 communicates with the suction chamber 4. In the example shown in FIG. 3, three compression chambers 51 are formed, and the third compression chamber 51 from the discharge port 5 communicates with the suction chamber 4.

The discharge pressure Pd is applied to the inside of the discharge port 5. Further, a suction pressure Ps lower than the discharge pressure Pd is applied to the inside of the suction chamber 4. Further, pressures P1, P2, and P3 are applied to the insides of the first to third compression chambers 51 from the discharge port 5, respectively. The pressures P1, P2, and P3 are respectively intermediate pressures that are higher than the suction pressure Ps and lower than the discharge pressure Pd. Hereinafter, "pressures P1, P2, P3" may be referred to as "intermediate pressures P1, P2, P3", respectively.

<Formation curve of scroll wrap>
Hereinafter, curves forming the scroll wraps of the orbiting scroll 11 and the fixed scroll 12 will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic view showing a relationship between a base circle 61 described later and an involute curve 60 described later. FIG. 5 is a schematic view showing a relationship between a tangent 62 of a base circle 61 described later and an involute curve 60 described later. 4 and 5 show the shapes of the curves forming the inner wall surface of the scroll wrap viewed from above (that is, viewed in the direction opposite to that of FIG. 3).

As shown in FIG. 4, generally, the curve forming the scroll wrap often employs an involute curve 60. The involute curve 60 is a curve drawn by the end of the yarn when the yarn wound around the circle is unwound, and is also referred to as a circle dissection line.

In addition, when a circle in which the yarn is wound is referred to as a base circle 61 and a state in which the yarn is completely wound is 0 degree, a straight line connecting the center of the base circle 61 and the start point of the yarn and the center of the base circle 61 The angle (internal angle) between the base circle 61 and the straight line connecting the contact points 63 (described later) is called the extension angle (or involute extension angle) λ. The contact point 63 is a point at which the base circle 61 and the tangent line 62 of the base circle 61 are in contact with each other. The tangent 62 of the base circle 61 is a straight line arranged to form a part of the line 162 shown in FIG. 7.

The distance ε1 from the contact point 63 with the base circle 61 to the first intersection point 64 with the involute curve 60 on the tangent line 62 of the base circle 61 shown in FIG. 4 can be obtained by the following equation (1).

Here, in Formula (1), each code represents the following.
ε 1 is the distance (unit: m (meters)) from the contact point 63 with the base circle 61 to the first intersection point 64 with the involute curve 60 on the tangent line 62 of the base circle 61. In addition, m (meter) of a unit may be converted by cm (centimeter) (following, the same).
a is the radius of the base circle 61 (unit: m).
λ _p1 is a dilation angle.

Furthermore, on the tangent line 62 of the base circle 61 shown in FIG. 5, the distance ε 2 from the first intersection point 64 with the involute curve 60 to the second intersection point 65 is equal to the length of the circumference of the base circle 61 Therefore, it is obtained by the following equation (2).

Here, in Formula (2), each code represents the following.
ε 2 is the distance (unit: m) from the first intersection point 64 with the involute curve 60 to the second intersection point 65 on the tangent 62 of the base circle 61.
a is the radius of the base circle 61 (unit: m).

The scroll wrap is formed along the involute curve 60 which satisfies the above-mentioned equation (1) and equation (2).

<The load generated on the orbiting scroll due to the input / output pressure difference of the compression mechanism at the time of stop>
The load generated on the orbiting scroll 11 by the input / output pressure difference (the pressure difference between the suction pressure and the discharge pressure) of the compression mechanism 3 at the time of stop will be described below with reference to FIGS. 6 to 9. FIG. 6 is a schematic view showing the positional relationship between the orbiting scroll wrap 11a and the fixed scroll wrap 12a. FIG. 7 is a schematic view showing the relationship between a working surface 67 described later and a virtual surface 69 described later. FIG. 8 is a schematic view showing the length of a virtual surface 69 described later around the discharge port 5. FIG. 9 is a schematic view showing a relationship between an adjacent surface 68 described later and a partial virtual surface 69m described later.

The action surface 67 (see FIG. 7) is a surface on which the suction pressure Ps acts (is applied).
The virtual surface 69 (see FIGS. 7 to 9) is a virtual surface on which all the pressure acts.
The adjacent surface 68 (see FIG. 9) is an outer wall surface of the orbiting scroll wrap 11a facing the mth (first in the example shown in FIG. 9) compression chamber 51m from the discharge port 5. The pressure (intermediate pressure) inside the compression chamber 51 acts (applies) on the adjacent surface 68 (see FIG. 9).
The partial virtual surface 69m (see FIG. 9) is a surface virtually formed along a line connecting the end points of the adjacent surfaces 68.

Here, the virtual surface 69 (see FIGS. 7 to 9) will be described as a cross section virtually formed in the height direction of the orbiting scroll wrap 11a along the line 162 shown in FIG. The line 162 (see FIG. 7) is disposed such that the central portion thereof passes through the center of the base circle 61, and from one of the intersections of the line 162 and the base circle 61, one side portion and the other side portion It is arranged to extend in parallel in the opposite direction. The line 162 (see FIG. 7) abuts the end of one side portion at the contact position between the outer wall surface of the outermost peripheral portion of the orbiting scroll wrap 11a and the inner wall surface of the fixed scroll wrap 12a. It arrange | positions so that an edge part may abut on the inner wall face of the outermost peripheral part of revolution scroll wrap 11a. The tangent 62 of the base circle 61 shown in FIGS. 4 and 5 constitutes the other side of the line 162. A virtual surface 69 (see FIGS. 7-9) is virtually formed along the line 162.

FIG. 6 shows the positional relationship between the orbiting scroll wrap 11a and the fixed scroll wrap 12a engaged at a certain rotation angle. In the example shown in FIG. 6, the outer wall surface of the outermost periphery of the orbiting scroll wrap 11a and the inner wall surface of the outermost periphery of the fixed scroll wrap 12a are in contact with each other at a position near the suction chamber 4 (see FIG. 3). FIG. 7 shows the action surface 67 on which the suction pressure Ps acts in the orbiting scroll wrap 11a in the positional relationship shown in FIG. The action surface 67 is an inner wall surface of a portion communicating with the suction chamber 4 in the orbiting scroll wrap 11 a in the positional relationship shown in FIGS. 6 and 7.

Here, first, the load of the suction pressure Ps acting on the orbiting scroll 11 will be examined.
The suction pressure Ps is generated by the working fluid flowing into the compression chamber 51 from the suction chamber 4. The suction pressure Ps acts on the action surface 67 (see FIG. 7) in the reverse rotation direction of the orbiting scroll 11. That is, the suction pressure Ps acts on the orbiting scroll 11 in the reverse rotation direction. Load T _Ps of the suction pressure Ps acting on the reverse rotation direction with respect to such orbiting scroll 11, load and suction pressure Ps of the suction pressure Ps acts on the working surface 67 is equal to the load applied to the virtual surface 69 Therefore, it is obtained by the following equation (3).

Here, in Formula (3), each code represents the following.
T _Ps is a load (unit: N (newton)) of the suction pressure Ps acting on the orbiting scroll 11 in the reverse rotation direction.
Ps is suction pressure (unit: N / m ² ).
L ₁ is the length (unit: m) of the virtual surface 69.
h is the height (unit: m) of the orbiting scroll wrap 11a.

In the vicinity of the discharge port 5, the dimension of the virtual surface 69 is as shown in FIG. Therefore, assuming that the number of compression chambers 51 is "n" and the thickness of the orbiting scroll wrap 11a is "t", from the dimensions of the virtual surface 69 around the discharge port 5 shown in FIG. The length L ₁ of the virtual surface 69 is obtained by the following equation (4). The partial virtual surface 69d shown in FIG. 8 will be described later.

Here, in the equation (4), each symbol represents the following.
L ₁ is the length (unit: m) of the virtual surface 69.
a is the radius of the base circle 61 (unit: m).
λ _p1 is a dilation angle.
t is the thickness (unit: m) of the orbiting scroll wrap 11a.
ε 2 is the distance (unit: m) from the first intersection point 64 with the involute curve 60 to the second intersection point 65 on the tangent 62 of the base circle 61.
n is the number of compression chambers 51.

Next, the load of the pressure (intermediate pressure) inside each compression chamber 51 acting on the orbiting scroll 11 will be examined.
As shown in FIG. 9, the intermediate pressure of the mth (for example, the first) compression chamber 51m from the discharge port 5 acts on the adjacent surface 68 of the orbiting scroll wrap 11a facing the compression chamber 51m. Partial virtual plane 69m is one that is virtually derived as a surface for receiving a load the T _m of the intermediate pressure acting on the adjacent surfaces 68. The partial virtual surface 69m is virtually along a line connecting the end points of the adjacent surface 68 of the orbiting scroll wrap 11a facing the m-th (first example in the example shown in FIG. 9) compression chamber 51m from the discharge port 5. It is a cross section formed in the height direction of orbiting scroll wrap 11a.

The intermediate pressure in the mth (for example, the first) compression chamber 51m from the discharge port 5 acts on the partial virtual surface 69m in the forward rotational direction. Then, in the m-th compression chamber 51m from the discharge port 5, load the T _m of the intermediate pressure acting on the forward rotational direction with respect to the orbiting scroll 11 is determined by the following equation (5).

Here, in Formula (5), each code represents the following.
T _m is a load (unit: N) of an intermediate pressure that acts on the orbiting scroll 11 in the forward rotational direction in the m-th compression chamber 51 m from the discharge port 5.
P _m is an intermediate pressure (unit: N / m ² ) of the m-th compression chamber 51 m from the discharge port 5.
a is the radius of the base circle 61 (unit: m).
h is the height (unit: m) of the orbiting scroll wrap 11a.

Then, in each of the first to n-th compression chambers 51 from the discharge port 5, the sum T _n of the loads of the intermediate pressure acting on the orbiting scroll 11 in the forward rotational direction is obtained by the following equation (6).

Here, in Formula (6), each code represents the following.
T _n is a sum of intermediate pressure loads (unit: N) acting on the orbiting scroll 11 in the forward rotational direction in the first to n-th compression chambers 51 from the discharge port 5.
a is the radius of the base circle 61 (unit: m).
h is the height (unit: m) of the orbiting scroll wrap 11a.
i is the order from the discharge port 5 of an arbitrary compression chamber 51.
n is the number of compression chambers 51.
Pi is an intermediate pressure (unit: N / m ² ) of any compression chamber 51.

Next, the load of the discharge pressure Pd acting on the orbiting scroll 11 will be examined.
The discharge pressure Pd acts on the wall surface of the orbiting scroll wrap 11 a facing the ejection port 5 in the forward rotation direction of the orbiting scroll 11. The partial virtual surface 69d shown in FIG. 8 is virtually derived as a surface that receives the load T _pd of the discharge pressure Pd acting on the wall surface of the orbiting scroll wrap 11a. That is, the discharge pressure Pd acts on the partial virtual surface 69d (see FIG. 8) in the forward rotational direction. The load _Tpd of the discharge pressure Pd that acts on the orbiting scroll 11 in the forward rotational direction is obtained by the following equation (7).

Here, in Formula (7), each code represents the following.
T _pd is a load (unit: N) of the discharge pressure Pd that acts on the orbiting scroll 11 in the forward rotational direction.
Pd is a discharge pressure (unit: N / m ² ).
a is the radius of the base circle 61 (unit: m).
λ _p1 is a dilation angle.
t is the thickness (unit: m) of the orbiting scroll wrap 11a.
h is the height (unit: m) of the orbiting scroll wrap 11a.

Here, assuming that the reverse rotation direction is a direction of a negative value with respect to the orbiting scroll 11 and the forward rotation direction is a direction of a positive value with respect to the orbiting scroll 11, the sum T of loads acting on the orbiting scroll 11 Is obtained from the equation (3), the equation (6) and the equation (7) by the following equation (8).

Here, in Formula (8), each code represents the following.
T is the sum of loads (unit: N) acting on the orbiting scroll 11.
T _Ps is a load (unit: N) of the suction pressure Ps acting on the orbiting scroll 11 in the reverse rotational direction.
T _n is a sum of intermediate pressure loads (unit: N) acting on the orbiting scroll 11 in the forward rotational direction in the first to n-th compression chambers 51 from the discharge port 5.
T _pd is a load (unit: N) of the discharge pressure Pd that acts on the orbiting scroll 11 in the forward rotational direction.
a is the radius of the base circle 61 (unit: m).
h is the height of the scroll wrap (unit: m).
Pd is a discharge pressure (unit: N / m ² ).
Ps is suction pressure (unit: N / m ² ).
λ _p1 is a dilation angle.
t is the thickness (unit: m) of the orbiting scroll wrap 11a.
i is the order from the discharge port 5 of an arbitrary compression chamber 51.
n is the number of compression chambers 51.
Pi is an intermediate pressure (unit: N / m ² ) of any compression chamber 51.

The scroll compressor S performs the capacity control to open the capacity control valve 45 (see FIG. 1), whereby the nth compression chamber 51n from the discharge port 5 is in communication with the suction chamber 4 side. Therefore, in the scroll compressor S, the sum T _ON of the load acting on the orbiting scroll 11 when the displacement control for opening the displacement control valve 45 (see FIG. 1) is performed is the number N (n − 1) Considering up to the second compression chamber 51 (n-1), the following equation (9) is obtained.

In addition, the scroll compressor S closes the displacement control valve 45 (see FIG. 1), whereby the nth compression chamber 51n from the discharge port 5 does not communicate with the suction chamber 4 side. Therefore, in the scroll compressor S, the sum T _OFF of the load acting on the orbiting scroll 11 when the displacement control valve 45 (see FIG. 1) is closed is from the discharge port 5 to the nth compression chamber 51n When considered, it is obtained by the following equation (10).

Here, in Formula (9) and Formula (10), each code represents the following.
T _ON is the sum of loads (unit: N) acting on the orbiting scroll 11 when the displacement control is performed to open the displacement control valve 45 (see FIG. 1).
T _OFF is the sum of loads (unit: N) acting on the orbiting scroll 11 when the displacement control is performed to close the displacement control valve 45 (see FIG. 1).
a is the radius of the base circle 61 (unit: m).
h is the height of the scroll wrap (unit: m).
Pd is a discharge pressure (unit: N / m ² ).
Ps is suction pressure (unit: N / m ² ).
λ _p1 is a dilation angle.
t is the thickness (unit: m) of the orbiting scroll wrap 11a.
i is the order from the discharge port 5 of an arbitrary compression chamber 51.
n is the number of compression chambers 51.
Pi is an intermediate pressure (unit: N / m ² ) of any compression chamber 51.

Therefore, the load ΔT relieved by performing the displacement control to open the displacement control valve 45 (see FIG. 1) can be obtained by the following equation (11) from the equations (9) and (10).

Here, in the equation (10), each symbol represents the following.
ΔT is a load that is relieved by performing displacement control to open the displacement control valve 45 (see FIG. 1).
a is the radius of the base circle 61 (unit: m).
h is the height of the scroll wrap (unit: m).
Pn is an intermediate pressure (unit: N / m ² ) of the n-th compression chamber 51 n from the discharge port 5.
Ps is suction pressure (unit: N / m ² ).

Note that these equations are equations that are applied when using asymmetric scroll wraps, and are not applied when using symmetric scroll wraps.

<Main Features of Scroll Compressor>
(1) As shown in FIG. 1, the scroll compressor S according to this embodiment includes the compression mechanism unit 3 forming a plurality of compression chambers 51 by the orbiting scroll 11 and the fixed scroll 12, and the internal space of the compression chamber 51. Input / output pressure difference (the suction pressure and the discharge pressure after the start of the stop process of the compression mechanism section 3), the bypass port 41 for communicating the suction side space with the outside and the opening and closing of the bypass port 41. Control unit (controller 30) that performs brake control to prevent reverse rotation of the compression mechanism unit 3 due to (pressure difference).

The scroll compressor S according to the present embodiment performs the brake control after the start of the stop process of the compression mechanism unit 3. The scroll compressor S according to the present embodiment rotates the load torque in the reverse rotational direction acting (applied) to the compression mechanism 3 at the time of stop under the condition that the input / output pressure difference is large (high pressure condition). It is possible to prevent the reverse rotation of the compression mechanism 3 by avoiding the brake torque in the stopping direction to be exceeded (exceeding). Therefore, the scroll compressor S according to the present embodiment can reliably prevent reverse rotation of the compression mechanism 3 at the time of stop.

(2) As shown in FIG. 2, in the scroll compressor S according to this embodiment, the control unit (controller 30) opens the bypass port 41 after starting the stop process of the compression mechanism unit 3 and then performs brake control. It is configured to start.

The scroll compressor S according to the present embodiment causes the working fluid in the compression chamber 51 to be partially bypassed to the suction side by opening the bypass port 41 after the start of the stopping process of the compression mechanism unit 3, thereby turning The gas load acting on the scroll 11 is reduced. That is, in the scroll compressor S according to the present embodiment, when the compression mechanism 3 is stopped, the load torque in the reverse rotation direction of the compression mechanism 3 generated by the input / output pressure difference by, for example, ΔT of the equation (11) described above. Reduce Thus, the scroll compressor S maintains the relationship of “load torque <brake torque” even under a large input-output pressure difference condition (high pressure condition). Thereafter, the scroll compressor S according to the present embodiment starts brake control. The scroll compressor S according to the present embodiment does not provide a check valve or the like for preventing the reverse rotation of the compression mechanism portion 3 and performs compression when the compression mechanism portion 3 is stopped by electrical means. Reverse rotation of the mechanism unit 3 can be prevented. Therefore, the scroll compressor S according to the present embodiment can reliably prevent reverse rotation of the compression mechanism 3 at the time of stop.

(3) As shown in FIG. 1, the scroll compressor S according to the present embodiment includes an elastic body (coil spring 46) that biases the displacement control valve 45 in the opening direction. Since the scroll compressor S urges the elastic body (coil spring 46) in the direction to open the displacement control valve 45, when the stopping process of the compression mechanism 3 is started, the displacement control valve 45 is automatically opened. be able to.

In the scroll compressor S according to the present embodiment, since the elastic body (coil spring 46) urges the displacement control valve 45 in the opening direction, when the stopping process of the compression mechanism 3 is started, the displacement control valve 45 It can be opened automatically. Thus, the scroll compressor S according to the present embodiment can reliably reduce the gas load acting on the orbiting scroll 11. As a result, the scroll compressor S according to the present embodiment can reliably prevent reverse rotation of the compression mechanism 3 at the time of stop.

As mentioned above, according to scroll compressor S concerning this embodiment, reverse rotation of compression mechanism part 3 at the time of stop can be prevented certainly.

The present invention is not limited to the above-described embodiment, but includes various modifications. For example, the above-described embodiments are described in detail to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Further, part of the configuration of the embodiment can be replaced with another configuration, and another configuration can be added to the configuration of the embodiment. In addition, it is possible to add, delete, and replace another configuration for part of each configuration.

DESCRIPTION OF SYMBOLS 1 airtight container

1a cylinder chamber

1b lid chamber 1c bottom chamber 2 motor part 2a stator 2b rotor 3 compression mechanism part 4 suction chamber 5 discharge port 6 crankshaft 6a oil supply vertical hole 6b oil supply horizontal hole 6c pin part 7 suction pipe 8 discharge pipe 9 Oil storage section 10 Lower bearing 11 Turning scroll 11a Turning scroll wrap 11b Turning end plate 11c Turning bearing unit 12 Fixed scroll 12a Fixed scroll wrap 12b Fixed end plate 13 Frame 13a Main bearing 14 Oldham ring 30 Controller (control unit)
40 switching device 41 bypass port 45 displacement control valve 46 coil spring (elastic body)
51 compression chamber 51 m discharge port 5 to m-th compression chamber 51 n discharge port 5 to n-th compression chamber 53 back pressure chamber 54 space in chamber 60 involute curve 61 base circle 62 tangent of base circle (straight line contacting base circle )
63 Base circle tangent point and base circle contact point 64 First intersection point of base circle tangent line and involute curve 65 Second intersection point of base circle tangent line and involute curve 67 Working surface of suction pressure 68 Compression chamber Adjacent surface 69 virtual surface 69 m partial virtual surface (intermediate pressure acting surface)
Ar Portion where check valve is removed Ps Suction pressure Pd Discharge pressure P1, P2, P3 Intermediate pressure S Scroll compressor

Claims

A compression mechanism unit that forms a plurality of compression chambers by the orbiting scroll and the fixed scroll;
A bypass port communicating the internal space of the compression chamber with the external suction side space;
A displacement control valve that switches the opening and closing of the bypass port;
A control unit that performs brake control to prevent reverse rotation of the compression mechanism unit due to an input / output pressure difference after start of stop processing of the compression mechanism unit;
In the scroll compressor according to claim 1,
The scroll compressor characterized in that the control unit starts the brake control after opening the bypass port after the start of the stopping process of the compression mechanism unit.
In the scroll compressor according to claim 2,
The scroll compressor further includes an elastic body that biases the capacity control valve in the opening direction.