JP6355453B2 - Scroll compressor - Google Patents

Description

  The present invention relates to a scroll compressor having an injection check valve.

Conventionally, an injection check valve is opened when the injection pressure is higher than the pressure in the compression chamber, and the injection refrigerant is injected into the compression chamber.
In such a case, when the injection pressure becomes lower than the pressure in the compression chamber, the injection check valve is closed to prevent the refrigerant in the compression chamber from flowing back into the injection circuit (see, for example, Patent Document 1). .

JP-A-3-43691 (FIG. 1)

  However, one injection circuit is configured for each injection port, and there is a difficulty in productivity and workability, such as providing a valve presser for each.

  In addition, in the structure of a conventional injection check valve, the injection port diameter must be considerably smaller than the outer diameter of the injection check valve, and in order to ensure the injection flow rate required by the refrigeration cycle. However, it was necessary to increase the check valve diameter at the same time.

  The present invention has been made to solve at least one of the above-described problems, and an object thereof is to increase the injection flow rate without changing the outer diameter of the injection check valve. And

The scroll compressor according to the present invention has a fixed base plate provided with a fixed spiral tooth on one surface, and a swing base plate provided with a swing spiral tooth on one surface, and the fixed base The fixed spiral teeth of the plate and the swing spiral teeth of the swing base plate mesh with each other to form a compression chamber between the fixed spiral teeth and the swing spiral teeth, and the injection refrigerant passes through the injection pipe. Te in the scroll compressor which is injected from the injection port to the compression chamber, wherein the fixed base plate, on the other side, the back plate is provided, be between the back plate and the fixing base plate, wherein is injection flow channel is formed between the injection pipe and the injection port, the injection port and a outflow hole connected to the inlet hole and the inlet hole, said indicator Injection check valve mechanism is composed of a injection check valves and spring disposed inlet side of transfection port is provided, the opening edge of the inlet hole and the opening edge of the outlet hole, the injection The back plate is provided with a valve presser that restricts the amount of movement of the injection check valve , shifted in a direction perpendicular to the length direction of the port.

  In the scroll compressor according to the present invention, since the center position of the injection check valve in the direction perpendicular to the axis is shifted from the center position in the direction perpendicular to the axis of the outflow hole of the injection port, the outer diameter of the injection check valve The injection flow rate can be increased without changing.

It is a longitudinal section showing the whole scroll compressor composition concerning an embodiment of the invention. It is a longitudinal cross-sectional view which shows the compression mechanism part of the scroll compressor which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the compression mechanism part of the scroll compressor which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the compression mechanism part of the scroll compressor which concerns on embodiment of this invention. It is a top view which shows the relationship between the fixed scroll of the scroll compressor which concerns on embodiment of this invention, and the components attached to this. FIG. 6 is a cross-sectional view taken along line AA in FIG. 5, and is an enlarged view of an injection check valve mechanism during non-injection operation. FIG. 6 is a cross-sectional view taken along line AA in FIG. 5, and is an enlarged view of an injection check valve mechanism at the time of injection operation.

The present invention will be described below with reference to illustrated embodiments.
In the following description, injection means that the liquid refrigerant (two-phase refrigerant or gas refrigerant) after exiting the condenser is returned to the middle of the compression chamber of the compressor and recompressed. Further, the liquid refrigerant (two-phase refrigerant) or gas refrigerant (on the high pressure side) after exiting the condenser is referred to as injection refrigerant. The term “after exiting the condenser” is not limited to the refrigerant immediately after exiting the condenser, and may be, for example, the refrigerant after passing through a predetermined expansion valve, a predetermined heat exchanger, or the like. The condenser may be read as a radiator, a heat exchanger that gives heat to the load side, or a gas cooler.

First, the overall configuration of the scroll compressor will be described with reference to FIG. FIG. 1 is a longitudinal sectional view showing the overall configuration of a scroll compressor according to an embodiment of the present invention.
As shown in FIG. 1, a scroll compressor 100 according to an embodiment of the present invention includes a fixed scroll 1, a swing scroll 2, a compliant frame 3, a guide frame 4, an electric motor 5, a sub frame 6, a shaft 7, and An Oldham mechanism 8 is housed and configured in a sealed container 10. The fixed scroll 1 and the orbiting scroll 2 are collectively referred to as a compression unit.

(Fixed scroll)
Next, the configuration of the fixed scroll will be described with reference to FIGS. FIG. 2 is a longitudinal sectional view showing a compression mechanism portion of the scroll compressor according to the embodiment of the present invention.
As shown in FIGS. 1 and 2, the fixed scroll 1 has a plate-like spiral tooth, that is, a fixed spiral tooth 1 b formed below the fixed base plate 1 a. In the scroll compressor 100, a compression chamber 20 is formed by meshing a fixed spiral tooth 1b of the fixed scroll 1 and a spiral tooth of a swing scroll 2, which will be described later, that is, a swing spiral tooth 2b.

  Two Oldham guide grooves 1c are formed in a substantially straight line on the lower outer peripheral portion of the fixed base plate 1a. A fixed claw 8b of the Oldham mechanism 8 is reciprocally engaged with the Oldham guide groove 1c.

  A discharge port 1d is formed through the fixed base plate 1a at a substantially central portion of the fixed base plate 1a. A relief port 1e is formed outside the discharge port 1d of the fixed base plate 1a so as to penetrate the fixed base plate 1a. An injection port 1f is formed outside the relief port 1e of the fixed base plate 1a so as to communicate the compression chamber side of the fixed base plate 1a and the opposite side thereof. The injection port 1f is provided with an injection check valve mechanism 35 to be described later. The fixed base plate 1a is formed with an inflow hole 1g penetrating from the side portion corresponding to the thickness of the plate to the upper portion. An injection pipe 41 is inserted into the opening at the side of the inflow hole 1g.

  A back plate 31 is provided on the upper side of the fixed base plate 1a. In the back plate 31, a discharge hole 31d is formed in a portion overlapping with the discharge port 1d, and a relief hole 31e is formed in a portion overlapping with the relief port 1e. In addition, an injection flow path 31a is formed between the fixed base plate 1a and the back plate 31 to connect the opening above the inflow hole 1g to the injection port 1f.

  The injection refrigerant flows from the outside of the hermetic container 10 into the inflow hole 1g through the injection pipe 41. The injection refrigerant that has flowed into the inflow hole 1g passes through the injection flow path 31a and is injected into the compression chamber 20 through the injection port 1f while pushing down the injection check valve 35a.

  An opening / closing valve 33 that opens and closes the discharge hole 31d and the relief hole 31e and a valve presser 34 that limits the lift amount of the opening / closing valve 33 are provided on the upper side of the back plate 31.

(Oscillating scroll)
Next, the configuration of the orbiting scroll will be described with reference to FIGS. FIG. 3 is a longitudinal sectional view showing a compression mechanism portion of the scroll compressor according to the embodiment of the present invention, and is a view showing the same portion as FIG. 2 described above.
As shown in FIGS. 1 and 3, the orbiting scroll 2 is formed with a plate-like orbiting spiral tooth 2b having substantially the same shape as the fixed spiral tooth 1b of the fixed scroll 1 on the upper side of the orbiting base plate 2a. Has been. As described above, the compression chamber 20 is formed by meshing the fixed spiral tooth 1 b of the fixed scroll 1 and the swing spiral tooth 2 b of the swing scroll 2.

  Two Oldham guide grooves 2e having a phase difference of about 90 degrees with respect to the Oldham guide groove 1c of the fixed scroll 1 are formed on the outer peripheral portion on the lower side of the swing base plate 2a on a substantially straight line. A swing side claw 8a of the Oldham mechanism 8 is reciprocally engaged with the Oldham guide groove 2e.

  A hollow cylindrical boss 2f is formed at the center of the lower side of the swing base plate 2a, and the inner side of the boss 2f is the swing bearing 2c. The swing shaft portion 7b at the upper end of the shaft 7 is engaged with the swing bearing 2c. A space between the rocking bearing 2c and the rocking shaft portion 7b is referred to as a boss portion internal space 15a.

  In addition, a thrust surface 2d is formed on the outer diameter side of the boss portion 2f so as to be slidable against the receiving surface of the thrust bearing 3a of the compliant frame 3. A space formed between the thrust surface 2d of the orbiting scroll 2 and the compliant frame 3 on the outer diameter side of the boss portion 2f is referred to as a boss portion external space 15b. A space formed between the swing base plate 2a of the swing scroll 2 and the compliant frame 3 on the outer diameter side of the thrust bearing 3a is referred to as a base plate outer diameter portion space 15c. The base plate outer diameter space 15c is a low pressure space of the suction gas atmosphere pressure (suction pressure).

  Further, the oscillating base plate 2a is provided with a bleed hole 2j penetrating from the upper surface to the lower surface. That is, the extraction hole 2j communicates the compression chamber 20 and the space on the thrust surface 2d side. The extraction hole 2j is arranged so that the circular locus drawn by the lower opening 2k, which is the opening of the extraction hole 2j on the compliant frame 3 side, during normal operation is always within the thrust bearing 3a of the compliant frame 3. Has been. Therefore, the refrigerant does not leak from the bleed hole 2j to the boss portion outer space 15b and the base plate outer diameter portion space 15c.

(Compliant frame and guide frame)
Next, the configuration of the compliant frame and the guide frame will be described with reference to FIGS. FIG. 4 is a longitudinal sectional view showing a compression mechanism portion of the scroll compressor according to the embodiment of the present invention, and is a view showing the same parts as those shown in FIGS.
As shown in FIGS. 1 and 4, the compliant frame 3 includes two upper and lower cylindrical surfaces provided on the outer peripheral portion, that is, an upper fitting cylindrical surface 3 d and a lower fitting cylindrical surface 3 e. It is supported in the radial direction by a cylindrical surface provided in the part, that is, an upper fitting cylindrical surface 4a and a lower fitting cylindrical surface 4b. At the center of the compliant frame 3, a main bearing 3c and an auxiliary main bearing 3h that support the shaft 7 driven to rotate by the electric motor 5 in the radial direction are formed.

  Here, the space formed between the guide frame 4 and the compliant frame 3 and partitioned vertically by ring-shaped upper and lower sealing materials 16a and 16b is referred to as a frame space 15d. Note that ring-shaped seal grooves for accommodating the upper and lower sealing materials 16a and 16b are formed at two locations on the inner peripheral surface of the guide frame 4. However, the seal groove may be formed on the outer peripheral side of the compliant frame 3.

  The compliant frame 3 penetrates from the receiving surface side of the thrust bearing 3a to the frame space 15d at a position facing the lower opening 2k of the bleed hole 2j, and constantly or intermittently the bleed hole 2j and the frame space 15d. A communication hole 3s is formed.

  Further, the compliant frame 3 is provided with an intermediate pressure adjusting valve mechanism 3p including a valve for adjusting the pressure of the boss portion outer space 15b, a valve presser, and an intermediate pressure adjusting spring 3m. The intermediate pressure adjusting spring 3m is stored in a compressed state in the intermediate pressure adjusting valve mechanism 3p.

  The compliant frame 3 is formed with a reciprocating sliding portion 3x on the outer peripheral side of the thrust bearing 3a, in which the Oldham mechanism annular portion 8c reciprocates. The reciprocating sliding portion 3x is formed with a communication hole 3n that communicates the base plate outer diameter space 15c (FIG. 3) with the suction space.

  The outer periphery of the guide frame 4 is fixed to the sealed container 10 by shrink fitting or welding. However, a notch is provided in the outer peripheral portion of the guide frame 4, and a flow path through which the refrigerant discharged from the compression chamber 20 into the sealed container 10 flows to the discharge pipe 43 is secured.

(axis)
Next, the configuration of the shaft will be described with reference to FIGS. 1, 3, and 4. FIG.
On the upper side of the shaft 7, an oscillating shaft portion 7 b that is rotatably engaged with the oscillating bearing 2 c of the oscillating scroll 2 is formed. A main shaft portion 7c that is rotatably engaged with the main bearing 3c and the auxiliary main bearing 3h of the compliant frame 3 is formed below the swing shaft portion 7b.

  On the lower side of the shaft 7, a sub shaft portion 7 d that is rotatably engaged with the sub bearing 6 a of the sub frame 6 is formed. The rotor 5a of the electric motor 5 is shrink-fitted between the auxiliary shaft portion 7d and the main shaft portion 7c, and the stator 5b is provided around the rotor 5a.

  An oil supply hole 7g is provided inside the shaft 7 so as to penetrate in the axial direction. Further, an oil pipe 7 f communicating with the oil supply hole 7 g is press-fitted into the lower end surface of the shaft 7.

Next, the fixed scroll and components attached thereto will be described with reference to FIGS. 1 to 4 based on FIGS. FIG. 5 is a top view showing the relationship between the fixed scroll of the scroll compressor according to the embodiment of the present invention and the components attached thereto. 6 is a cross-sectional view taken along line AA in FIG. 5 and is an enlarged view showing an injection check valve mechanism during non-injection operation. FIG. 7 is a cross-sectional view taken along line AA in FIG. 5 and is an enlarged view of the injection check valve mechanism during the injection operation. In FIG. 5, components that are not originally visible are indicated by broken lines.
As shown in FIGS. 1 to 5, a discharge port 1d is formed at the center of the fixed base plate 1a so as to penetrate the fixed base plate 1a from the lower side to the upper side. A relief port 1e is formed on the outer periphery of the fixed base plate 1a from the discharge port 1d so as to penetrate the fixed base plate 1a from the lower side to the upper side. An injection port 1f is formed on the outer peripheral side of the relief port 1e of the fixed base plate 1a so as to penetrate the fixed base plate 1a from the lower side to the upper side. The fixed base plate 1a is formed with an inflow hole 1g communicating from the side to the top.

On the upper side of the fixed base plate 1a, a back plate 31 that covers substantially the entire fixed base plate 1a is provided, and several places are fixed to the fixed base plate 1a with bolts (not shown). Thereby, the fixed base plate 1a and the back plate 31 are in close contact with each other.
Instead of directly fixing the back plate 31 to the fixed base plate 1a, a packing made of a rubber material may be interposed between the joint surfaces of the fixed base plate 1a and the back plate 31. Thereby, the sealing performance of the joint surface of the fixed base plate 1a and the back plate 31 can be improved.

  In the back plate 31, a discharge hole 31d is formed in a portion overlapping with the discharge port 1d, and a relief hole 31e is formed in a portion overlapping with the relief port 1e. Therefore, the compression chamber 20 and the space above the back plate 31 (the space in the sealed container 10) communicate with each other via the discharge port 1d and the discharge hole 31d. Similarly, the compression chamber 20 and the space above the back plate 31 communicate with each other via the relief port 1e and the relief hole 31e.

  Further, as shown in FIGS. 5 to 7, a continuous groove is formed in the back plate 31 from a position overlapping the opening above the inflow hole 1 g to a position overlapping the injection port 1 f. By this groove, an injection flow path 31a is formed between the fixed base plate 1a and the back plate 31 to connect from the upper opening of the inflow hole 1g to the injection port 1f. The back plate 31 is formed so that the edge of the groove forming the injection flow path 31a slightly covers the opening surface of the injection port 1f, and this portion serves as a valve presser 31b that prevents the injection check valve 35a from dropping off. It is supposed to function. Thereby, it is not necessary to separately provide a means for preventing the injection check valve 35a from falling off, the manufacturing process can be simplified, the productivity can be improved, and the manufacturing cost can be reduced.

  Further, as shown in FIGS. 6 and 7, the injection check valve mechanism 35 includes a center position in the direction perpendicular to the axis of the outflow hole of the injection port 1f and a center position in the direction perpendicular to the axis of the injection check valve 35a, that is, the spring 35b. It is configured to shift. Thereby, the injection flow rate can be increased without changing the outer diameter of the injection check valve 35a.

  An injection pipe 41 is inserted into the opening at the side of the inflow hole 1g (FIGS. 1 and 2). The injection refrigerant flows into the inflow hole 1g from the outside of the sealed container 10 through the injection pipe 41. The injection refrigerant that has flowed into the inflow hole 1g passes through the injection flow path 31a and is injected into the compression chamber 20 through the injection port 1f while pushing down the injection check valve 35a of the injection check valve mechanism 35. The injection check valve 35a is pushed up by the spring 35b during non-injection operation, and shuts off the injection port 1f and the injection flow path 31a by using the back plate 31 as a valve presser. Further, as described above, since the center positions of the injection port 1f and the injection check valve mechanism 35 in the direction perpendicular to the axis are different, the flow path width 1h of the injection port 1f shown in FIG. 7 can be adjusted. A combined injection flow path can be formed.

  Here, the groove is formed in the back plate 31 and the injection flow path 31a is formed here, but the groove is formed in the fixed base plate 1a instead of the back plate 31, and the injection flow path 31a is formed. It is good.

On the upper side of the back plate 31, as shown in FIGS. 2 and 5, an on-off valve 33 and a valve presser 34, which are relief valves, are fixed to the back plate 31 and the fixed base plate 1a by bolts (not shown). The The on-off valve 33 is a reed valve that opens and closes the discharge hole 31d and the relief hole 31e. The on-off valve 33 is a reed valve that opens and closes due to a pressure difference between the pressure of the refrigerant in the compression chamber 20 and the pressure (discharge pressure) of the refrigerant in the sealed container 10. The valve retainer 34 limits the lift amount of the on-off valve 33.
Here, one on-off valve 33 for opening and closing the discharge hole 31d and the relief hole 31e is provided. However, the on-off valve 33 may be provided separately for each of the discharge hole 31d and the relief hole 31e.

Next, the operation of the scroll compressor 100 will be described with reference to FIGS.
The low-pressure suction refrigerant flows from the suction pipe 42 into the compression chamber 20 formed by the fixed spiral teeth 1b of the fixed scroll 1 and the swing spiral teeth 2b of the swing scroll 2. Moreover, the injection refrigerant that has flowed into the inflow hole 1g from the outside via the injection pipe 41 is injected into the compression chamber 20 from the injection port 1f through the injection flow path 31a. When the injection operation is not performed, the injection check valve 35 a of the injection check valve mechanism 35 is closed as shown in FIG. 6, and the injection refrigerant is not injected into the compression chamber 20.

  The shaft 7 is driven by the electric motor 5 and the swing scroll 2 is driven. The orbiting scroll 2 does not rotate by the Oldham mechanism 8 but performs a revolving motion (eccentric turning motion) to perform a compression operation for gradually reducing the volume of the compression chamber 20. By this compression operation, the refrigerant in the compression chamber 20 becomes high pressure and is discharged into the sealed container 10 via the discharge port 1 d of the fixed scroll 1. The discharged refrigerant is discharged out of the sealed container 10 from the discharge pipe 43. That is, the inside of the sealed container 10 becomes a high pressure.

  As described above, the inside of the sealed container 10 becomes a high pressure during the steady operation. Due to this pressure, the refrigerating machine oil 11 accumulated at the bottom of the sealed container 10 flows upward through the oil pipe 7f and the oil supply hole 7g. The high-pressure refrigerating machine oil 11 is guided to the boss portion internal space 15a (FIG. 3), is reduced to an intermediate pressure Pm1 higher than the suction pressure and lower than the discharge pressure, and flows to the boss portion outer space 15b (FIG. 3).

  Further, the high-pressure oil flowing through the oil supply hole 7g is guided between the main bearing 3c and the main shaft portion 7c (FIGS. 1 and 4) from a lateral hole provided in the shaft 7. The refrigerating machine oil 11 guided between the main bearing 3c and the main shaft portion 7c is depressurized between the main bearing 3c and the main shaft portion 7c to an intermediate pressure Pm1 that is higher than the suction pressure and lower than the discharge pressure, and the boss portion outer space 15b. (See FIG. 3).

  The refrigerating machine oil 11 that has reached the intermediate pressure Pm1 in the boss portion external space 15b is foamed refrigerant that has been dissolved in the refrigerating machine oil 11, and generally has two phases, that is, a gas refrigerant and the refrigerating machine oil 11.

  The refrigeration oil 11 that has become the intermediate pressure Pm1 in the boss portion outer space 15b flows into the base plate outer diameter portion space 15c (FIGS. 3 and 4) through the intermediate pressure regulating valve mechanism 3p. The refrigerating machine oil 11 that has flowed into the base plate outer diameter space 15c is discharged to the inside of the Oldham mechanism annular portion 8c (FIG. 4) through the communication hole 3n (FIG. 4). Here, when the refrigerating machine oil 11 passes through the intermediate pressure adjusting valve mechanism 3p, it overcomes the force applied by the intermediate pressure adjusting spring 3m (see FIG. 4), and pushes up the valve of the intermediate pressure adjusting valve mechanism 3p to raise the base plate It flows into the outer diameter space 15c (FIG. 3).

  Further, the refrigerating machine oil 11 having the intermediate pressure Pm1 in the boss portion outer space 15b is supplied to the thrust surface 2d (FIG. 3) of the orbiting scroll 2 and the sliding portion of the thrust bearing 3a (FIG. 3) of the compliant frame 3. And discharged to the inside of the Oldham mechanism annular portion 8c (FIG. 4). Then, oil is supplied to the sliding surfaces of the swing-side claw 8a (FIG. 3) and the fixed-side claw 8b (FIG. 2) of the Oldham mechanism 8, and then released to the base plate outer diameter space 15c (FIG. 3). .

  Here, the intermediate pressure Pm1 in the boss portion outer space 15b is determined by a predetermined pressure α that is substantially determined by the spring force of the intermediate pressure adjusting spring 3m of the intermediate pressure adjusting valve mechanism 3p and the exposed area of the valve, “Pm1 = Ps + α. ". Note that Ps is a suction atmosphere pressure, that is, a low pressure.

Further, the lower opening 2k (FIG. 4) of the bleed hole 2j communicates with the opening on the thrust bearing 3a side of the communication hole 3s provided in the compliant frame 3 constantly or intermittently. For this reason, the refrigerant gas in the middle of compression from the compression chamber 20 is guided to the frame space 15d (FIG. 4) through the extraction holes 2j of the orbiting scroll 2 and the communication holes 3s of the compliant frame 3. Since the refrigerant gas is being compressed, the refrigerant gas has an intermediate pressure Pm2 that is higher than the suction pressure and lower than the discharge pressure.
Even if the refrigerant gas is guided, the frame space 15d is a closed space sealed by the upper seal material 16a and the lower seal material 16b, and therefore compressed in response to pressure fluctuations in the compression chamber 20 during normal operation. The chamber 20 and the frame space 15d have a slight flow in both directions. That is, the compression chamber 20 and the frame space 15d are in a state of breathing.

  Here, the intermediate pressure Pm2 in the frame space 15d is expressed as “Pm2 = Ps × β” by a predetermined magnification β substantially determined by the position of the compression chamber 20 in communication. Note that Ps is a suction atmosphere pressure, that is, a low pressure.

Here, the compliant frame 3 has a total of (A) a force caused by the intermediate pressure Pm1 in the boss portion outer space 15b and (B) a pressing force from the orbiting scroll 2 via the thrust bearing 3a (A + B). ) Acts as a downward force.
On the other hand, for the compliant frame 3, (C) the sum of the force due to the intermediate pressure Pm2 in the frame space 15d and (D) the force due to the high pressure acting on the portion exposed to the high pressure atmosphere at the lower end surface. (C + D) acts as an upward force.
During normal operation, the upward force (C + D) is set to be greater than the downward force (A + B).

During normal operation, since the upward force (C + D) is set to be greater than the downward force (A + B), the compliant frame 3 is lifted to the fixed scroll 1 side (upper side in FIG. 1). That is, in the compliant frame 3, the upper fitting cylindrical surface 3d is guided by the upper fitting cylindrical surface 4a of the guide frame 4, and the lower fitting cylindrical surface 3e is guided by the lower fitting cylindrical surface 4b of the guide frame 4. Thus, it is in a state of being lifted to the fixed scroll 1 side (upper side in FIG. 1). That is, the compliant frame 3 floats to the fixed scroll 1 side (upper side in FIG. 1) and is pressed against the orbiting scroll 2 via the thrust bearing 3a.
Since the compliant frame 3 is pressed against the orbiting scroll 2, the orbiting scroll 2 is also lifted to the fixed scroll 1 side (upper side in FIG. 1) like the compliant frame 3. As a result, the tip of the oscillating spiral tooth 2b of the oscillating scroll 2 comes into contact with the tooth bottom (fixed base plate 1a) of the fixed scroll 1, and the tooth tip of the fixed vortex tooth 1b of the fixed scroll 1 The tooth bottom (oscillating base plate 2a) of the moving scroll 2 comes into contact.

  On the other hand, during a transition period such as when the compressor is started, or when the internal pressure of the compression chamber 20 rises abnormally, the pressing force from the orbiting scroll 2 via the thrust bearing 3a of (B) described above is applied. growing. Therefore, the downward force (A + B) is larger than the upward force (C + D). As a result, the compliant frame 3 is pressed to the guide frame 4 side (lower side in FIG. 1). Then, the tooth tip of the rocking spiral tooth 2b of the rocking scroll 2 and the tooth bottom (fixed base plate 1a) of the fixed scroll 1 are separated, and the tooth tip of the fixed coiling tooth 1b of the fixed scroll 1 and the rocking scroll. 2 tooth bottom (oscillation base plate 2a) is separated. Thereby, the pressure in the compression chamber 20 falls, and the pressure in the compression chamber 20 is prevented from rising excessively.

  During the injection operation, an external injection refrigerant flows into the inflow hole 1g via the injection pipe 41, and is injected into the compression chamber 20 from the injection port 1f via the injection flow path 31a. At this time, the low-pressure refrigerant sucked from the suction pipe 42 flows into the compression chamber 20 formed by the fixed spiral teeth 1b of the fixed scroll 1 and the swing spiral teeth 2b of the swing scroll 2, and is compressed. However, when the pressure in the compression chamber 20 when communicating with the injection port 1 f is smaller than the injection pressure, the spring 35 b force of the injection check valve mechanism 35 is overcome and the injection refrigerant flows into the compression chamber 20. When the injection pressure is smaller than the pressure in the compression chamber 20, the injection check valve 35 a is not opened, and the injection refrigerant does not flow into the compression chamber 20. The operating condition in which the injection pressure is lower than the pressure in the compression chamber 20 is a condition that generally does not require injection, and in most cases, the unit-side valve for allowing the injection refrigerant to flow into the scroll compressor 100 is closed.

  Next, the effect of the injection check valve 35a will be described. The injection check valve 35a has an effect of improving performance in a condition that mainly does not require injection operation. As shown in FIG. 5, after passing through the injection flow path 31a, the injection refrigerant branches and is injected into the compression chamber 20 through two or three injection ports 1f. The branched injection port 1 f is fixed to a compression chamber (hereinafter referred to as “compression chamber A”) formed by the inward surface of the orbiting scroll 2 and the outward surface of the fixed scroll 1 and the outward surface of the orbiting scroll 2. Each communicates with a compression chamber (hereinafter referred to as a compression chamber B) formed by the inward surface of the scroll 1. When the shaft 7 is at a certain rotation angle and the timing at which the injection port 1 f communicates with the compression chamber A and the compression chamber B is different, the injection flow path in a state where the pressure in the compression chamber A and the pressure in the compression chamber B are different It will communicate with 31a. If the injection operation is not performed, the compression chamber A and the compression chamber B communicate from the higher pressure side to the lower pressure side via the injection flow path 31a, so-called breathing. In the breathing state, recompression of the refrigerant occurs in the compression chamber 20, resulting in an increase in input and a decrease in performance. However, by providing the injection check valve mechanism 35, the compression chamber A and the compression chamber B do not communicate with each other via the injection flow path 31a, and the respiratory motion is eliminated. For this reason, recompression of a refrigerant can be prevented and performance can be improved.

  In addition, when the injection check valve mechanism 35 is assembled, the assembly of the injection check valve 35a can be simplified by substituting the valve retainer 31b of the injection check valve 35a with the back plate 31. Of course, you may use the method of improving sealing performance, such as press-fitting a valve press to the fixed base plate 1a of the fixed scroll 1. FIG. Furthermore, since the flow path width 1h of the injection port 1f can be freely changed, it is possible to take an appropriate shape to ensure the injection flow rate required by the unit.

  DESCRIPTION OF SYMBOLS 1 Fixed scroll, 1a Fixed base plate, 1b Fixed spiral tooth, 1c Oldham guide groove, 1d Discharge port, 1e Relief port, 1f Injection port, 1g Inflow hole, 1h Channel width, 2 Swing scroll, 2a Swing base plate 2b Oscillating spiral teeth, 2c Oscillating bearing, 2d Thrust surface, 2e Oldham guide groove, 2f Boss part, 2j Bleed hole, 2k Lower opening part, 3 Compliant frame, 3a Thrust bearing, 3c Main bearing, 3d Top fitting Joint cylindrical surface, 3e lower fitting cylindrical surface, 3h auxiliary main bearing, 3m intermediate pressure adjusting spring, 3p intermediate pressure adjusting valve mechanism, 3s, 3n communication hole, 3x reciprocating sliding part, 4 guide frame, 4a upper fitting cylinder Surface, 4b Lower fitting cylindrical surface, 5 Electric motor, 5a Rotor, 5b Stator, 6 Subframe, 6a Sub bearing, 7 shaft, 7b Oscillating shaft, 7 c Main shaft part, 7d Subshaft part, 7g Oil supply hole, 7f Oil pipe, 8 Oldham mechanism, 8a Oscillating side claw, 8b Fixed side claw, 8c Oldham mechanism annular part, 10 Airtight container, 11 Refrigerating machine oil, 15a Inside boss part Space, 15b boss outer space, 15c base plate outer diameter space, 15d frame space, 16a upper seal material, 16b lower seal material, 20 compression chamber, 31 back plate, 31a injection flow path, 31b valve retainer, 31d discharge hole 31e Relief hole, 33 Open / close valve, 34 Valve presser, 35 Injection check valve mechanism, 35a Injection check valve, 35b Spring, 41 Injection pipe, 42 Suction pipe, 43 Discharge pipe, 100 Scroll compressor.

Claims (3)

A fixed base plate provided with fixed spiral teeth on one surface;
An oscillation base plate provided with oscillation spiral teeth on one surface,
By engaging the fixed spiral teeth of the fixed base plate and the swing spiral teeth of the swing base plate, a compression chamber is formed between the fixed spiral teeth and the swing spiral teeth,
In the scroll compressor injection refrigerant is injected from the injection port to the compression chamber via the injection pipe,
The fixed base plate is provided with a back plate on the other surface,
Between the fixed base plate and the back plate, an injection flow path is formed between the injection pipe and the injection port,
The injection port has an inflow hole and an outflow hole connected to the inflow hole, and is provided with an injection check valve mechanism arranged on the inflow hole side of the injection port and a spring. And
The opening edge of the inflow hole and the opening edge of the outflow hole are shifted in a direction orthogonal to the length direction of the injection port ,
The scroll compressor according to claim 1, wherein the back plate includes a valve presser that regulates a movement amount of the injection check valve. The injection check valve is accommodated in the injection port that penetrates the fixed base plate from the one surface on the fixed spiral tooth side where the compression chamber is formed to the other surface,
The fixed base plate further has an inflow hole communicating from the side corresponding to the thickness of the plate to the other surface,
The back plate is provided so as to cover the other surface of the fixed base plate, and connects the opening of the other surface of the inflow hole and the injection port between the fixed base plate. The scroll compressor according to claim 1, wherein a flow path is formed. The scroll compressor according to claim 1 or 2 , wherein the fixed base plate is provided with an on-off valve that discharges the refrigerant compressed to a pressure higher than a preset discharge pressure.

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