JP3750169B2 - Hermetic compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hermetic compressor that is mainly used in a refrigerator or an air conditioner and has a casing equipped with a compression mechanism.
[0002]
[Prior art]
Conventionally, as a hermetic compressor, for example, a casing is provided with a scroll compression mechanism, a high-pressure chamber in which a discharge port of the compression mechanism and an external discharge pipe are opened on one side of the compression mechanism, and a suction pipe on the other side. There is a low-pressure dome type scroll compressor in which a low-pressure chamber in which a motor is disposed is formed, but in recent years, as an alternative chlorofluorocarbon, as a refrigerant, for example, from R32 (50 wt%), R125 (50 wt%) A refrigerant R410A or the like is used.
[0003]
However, when the refrigerant R410A is used, if the operation is performed under a condition where the condensing temperature is high within the range of temperature conditions during normal operation, the capacity is lower than that of a conventional refrigerant, for example, R22 of a chlorofluorocarbon refrigerant. Yes, specifically, for example, the refrigerant R410A when the rated temperature condition becomes the condensing temperature 55 ° C. is used so that the rated temperature condition becomes the same capacity as the operating capacity where the condensing temperature becomes 55 ° C. by using the refrigerant R22. When the cylinder volume in this case is set, for example, compared to the case where R22 is used for the chlorofluorocarbon refrigerant, the capacity is insufficient by 8% at a condition where the condensation temperature is high within the range of normal operation, for example, at a condensation temperature of 65 ° C.
[0004]
Therefore, there is a method of controlling the capacity as a measure for increasing the capacity under conditions where the condensation temperature is high. As shown in FIG. 6, the scroll compressor capable of controlling the capacity includes a compression mechanism CF including a fixed scroll B and a revolving scroll C in a casing A, and the casing A is fixed by the fixed scroll B. The high pressure chamber D is divided into the low pressure chamber E, the discharge port F provided in the fixed scroll B is opened in the high pressure chamber D, and the discharge pipe G is opened. The suction pipe is opened, and the low pressure gas sucked from the suction pipe is sucked into the compression mechanism CF and compressed, and then discharged from the discharge port F to the high pressure chamber D.
[0005]
The end plate B1 of the fixed scroll B is provided with a bypass hole J that opens in the compression stroke of the compression chamber H formed between the scrolls B and C, and a bypass passage K that communicates the bypass hole J with the suction side. An unloader piston that is formed and integrally formed with a cylindrical portion that protrudes outward in the axial direction at a position facing the bypass hole J in the end plate B1 and opens and closes the bypass passage K. L is a cylinder M that houses L, and a spring N that urges the piston L in a direction away from the bypass hole J is housed in the cylinder M. The high pressure that overcomes the urging force of the spring N and causes the piston L to be seated in the bypass hole J acts as a back pressure, and during unloading operation, the low pressure acts as a back pressure to act as a piston. Is separated from the bypass hole J by the urging force of the spring N, and during normal operation, when the condensation temperature is lower than a predetermined temperature, the bypass hole J leading to the compression chamber H is opened and communicated with the low pressure side. Thus, the compression operation is performed with a small capacity, and during the normal operation, when the condensing temperature becomes higher than a predetermined temperature, the bypass hole J leading to the compression chamber H is closed and the communication with the low pressure side is shut off to perform the full load operation. Therefore, the compression operation is performed with a large capacity.
[0006]
In other words, the compression capacity during unload operation is defined as the capacity when operating at the rated temperature condition at which the specified condensation temperature is reached, and when operating at a condensation temperature higher than this rated temperature condition, the compression capacity is reduced by full load operation. I try to raise it.
[0007]
[Problems to be solved by the invention]
However, when it is intended to prevent the discharge pressure from increasing by controlling the capacity of the scroll compressor, a pressure sensor may be installed outside the compressor in order to detect an abnormal increase in the discharge pressure, as shown in FIG. Since it is necessary to connect a pressure introduction pipe P for applying a back pressure to the unloader piston L, and to select and introduce a high pressure and a low pressure into the pressure introduction pipe P, it is possible to switch the pressure. For example, a large number of external parts are required, such as the need for the electromagnetic valve Q, which not only complicates the piping structure but also increases the cost.
[0008]
The present invention has been made in view of the above problems, and provides a hermetic compressor capable of improving the compression capacity at the time of high condensing temperature operation with a simple structure even when an alternative chlorofluorocarbon refrigerant is used. With the goal.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is a hermetic compressor in which a compression mechanism CF is housed in a casing 1, and the compression mechanism CF has a rating that a high pressure on the discharge side defines within a range of normal operation. When the pressure is lower than the set pressure based on the condensation temperature of the temperature condition, the intermediate pressure chamber 51 during compression is opened to the low pressure region on the suction side, and when the high pressure on the discharge side exceeds the set pressure, the intermediate pressure chamber during compression A capacity control mechanism 6 that shuts off 51 from a low-pressure region on the suction side. The capacity control mechanism 6 has a valve body 7 seated and separated from an opening 24 that opens the intermediate pressure chamber 51 to the suction side; An urging body 9 that urges the valve body 7 to the anti-seat side, and a high-pressure action portion 61 that seats the valve body 7 against the urging body 9 when the high pressure exceeds a set pressure are provided. part 61, exposed to the high pressure chamber 41 the compressed gas is discharged.
[0010]
Examples of the compression mechanism include a scroll compression mechanism and a rotary compression mechanism.
[0011]
Further, the low pressure range on the suction side means, for example, a low pressure space or a suction pipe in a casing into which suction gas is introduced.
[0012]
The set pressure of the high pressure on the discharge side means a high pressure based on the condensation temperature of the rated temperature condition determined within the range of normal operation. For example, the capacity of the alternative chlorofluorocarbon refrigerant R410A is compared with the compression capacity of the chlorofluorocarbon refrigerant R22. The discharge side high pressure when the condensation temperature starts to decrease.
[0013]
The capacity control mechanism 6 is formed by means such as a capacity control valve, for example.
[0014]
With the above configuration, in the invention according to claim 1, when using an alternative chlorofluorocarbon refrigerant that causes a reduction in compression capacity when the condensation temperature becomes high, when operating at a predetermined condensation temperature that is a rated temperature condition, that is, When the high pressure on the discharge side is equal to or lower than the set pressure, the intermediate pressure chamber 51 during compression is opened to the low pressure region on the suction side, and the unload operation is performed. When operating at a condensing temperature higher than the rated temperature condition where the compression capacity is reduced, that is, when the high pressure pressure on the discharge side exceeds the set pressure, the intermediate pressure during compression The full load operation is performed by shutting off the chamber 51 from the low pressure region on the suction side, and the compression capacity can be increased even when the chamber 51 is operated at a high condensation temperature.
[0015]
The invention according to claim 2 is the invention according to claim 1, wherein the compression mechanism CF is composed of a fixed scroll 2 and a revolving scroll 3 that define two symmetrical compression chambers, and the capacity control mechanism 6 is respectively A pair is provided corresponding to the intermediate pressure chambers 51 of the system.
[0016]
With the above configuration, in the invention described in claim 2, even in the scroll-type hermetic compressor having two compression chambers, the capacity control mechanism 6 is provided corresponding to the intermediate pressure chambers 51, 51 of each system. Therefore, the pressure in each intermediate pressure chamber 51, 51 can be increased satisfactorily without breaking the pressure balance.
[0018]
With the above configuration, in the invention described in claim 1 , capacity control can be performed with a simple structure in which the valve body 7 is operated by the difference between the urging force of the urging body 9 and the high pressure on the discharge side. Thus, when performing capacity control, it is not necessary to arrange parts outside the compressor, the piping structure is not complicated, and the number of parts is not increased, so that the cost can be reduced.
[0019]
In addition, after being left standing for a long time, such as sleeping, the pressure on the high-pressure side and the low-pressure side are in a balanced state, that is, the high pressure on the discharge side is below the set pressure. It has become. For this reason, the liquid compression that occurs at the time of start-up of the bed is also released from the opening 24 to the low pressure range, and the liquid compression can be avoided.
[0020]
According to a third aspect of the present invention, in the first aspect of the present invention, the counter seat side of the valve element 7 is inserted into a through hole 43 provided in the pressure partition 4 that partitions the inside of the casing 1 into a high pressure side and a low pressure side. The anti-seat side end face of the valve body 7 is opened to the high pressure side to form the high pressure action portion 61.
[0021]
With the above configuration, in the invention described in claim 3 , the discharge gas discharged to the high pressure side in the casing 1 partitioned by the pressure partition wall 4 is formed on the high pressure acting portion 61 formed on the end surface on the opposite side of the valve body 7. When the pressure on the discharge side exceeds the set pressure by the action, that is, when the pressure on the high pressure side in the casing 1 becomes equal to or higher than the set pressure, the valve body 7 is moved against the biasing body 9 with this high pressure. The valve body 7 can be easily operated by being seated in the opening 24.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. The hermetic compressor according to the present embodiment is a scroll compressor, and includes a compression mechanism CF provided in the upper part of the hermetic casing 1 and a motor (not shown) provided in the lower part of the casing 1, The mechanism CF includes a fixed scroll 2 and a revolving scroll 3. These scrolls 2 and 3 are arranged in a vertically opposed manner via a frame 11, and the revolving scroll 3 is interlocked with a drive shaft 12 of the motor. On the other hand, a pressure partition 4 that divides the inside of the casing 1 up and down is disposed on the upper side of the fixed scroll 2 inside the casing 1, and a discharge port 22 formed in the fixed scroll 2 above the pressure partition 4. Is formed through the pressure partition wall 4 and the high pressure chamber 41 on the high pressure side for opening the external discharge pipe 13 is formed, and the suction pipe 1 is formed below the pressure partition wall 4. There is open, is of the low-pressure chamber 42 to be the low pressure side to dispose the motor was defined and formed.
[0023]
Accordingly, the revolution scroll 3 is revolved with respect to the fixed scroll 2 by the rotation of the drive shaft 12 accompanying the drive of the motor, and the low pressure sucked into the low pressure chamber 42 from the suction pipe 14 by this revolution drive. Gas is sucked into the compression chamber 5 formed by the spiral bodies 21, 31 of the scrolls 2, 3, the sucked gas is compressed, and the compressed gas is supplied from the discharge port 22 to the high pressure chamber 41. It is discharged and discharged from the external discharge pipe 13 to the outside of the casing 1.
[0024]
Thus, in the scroll compressor described above, when the high pressure on the discharge side is equal to or lower than the set pressure, the intermediate pressure chamber 51 during compression is opened to the low pressure region on the suction side and the high pressure on the discharge side is set. When the pressure exceeds the set pressure, the capacity control mechanism 6 is provided that shuts off the intermediate pressure chamber 51 during the compression from the low pressure region on the suction side.
[0025]
That is, the capacity control mechanism 6 is provided in a pair corresponding to the intermediate pressure chambers 51, 51 of each system in the two symmetrical compression chambers 5 formed by the fixed scroll 2 and the revolution scroll 3.
[0026]
The configuration of the capacity control mechanism 6 will be described in detail. The capacity control mechanism 6 is opened axially outward at positions corresponding to the intermediate pressure chambers 51, 51 in the end plate 23 of the fixed scroll 2. A cylinder 8 in which the body 7 is housed is formed.
[0027]
Further, the end plate 23 of the fixed scroll 2 is formed with an opening 24 through which the inside of the cylinder 8 and the intermediate pressure chamber 51 communicate with each other, extends in the radial direction, has one end opened in the cylinder 8, and the other end Forms a bypass passage 25 that opens to the outer peripheral surface of the fixed scroll 2 so that the intermediate pressure chamber 51 can be opened to the suction side via the opening 24, the cylinder 8, and the bypass passage 25.
[0028]
Further, the valve body 7 of the capacity control mechanism 6 is inserted into the cylinder 8 and has a small diameter portion 71 having a smaller diameter than the inner diameter of the cylinder 8 and capable of disposing an urging body 9 made of a spring around the cylinder. A projection 73 extending in the axial direction is formed at the center of the large-diameter portion 72 opposite to the small-diameter portion 71. 73 is inserted into a through-hole 43 formed in the pressure partition 4 via a sealing material 44, the end surface of the protrusion 73 is exposed to the high-pressure chamber 41, the end surface forms the high-pressure acting portion 61, and the tip of the small-diameter portion 71 A tapered convex portion 74 that can be seated and separated from the opening 24 is formed in the central portion.
[0029]
When the valve body 7 is inserted into the cylinder 8, the valve body 7 is inserted into the cylinder 8 with the biasing body 9 fitted around the small diameter portion 71 of the valve body 7, The valve presser 81 attached to the upper surface of the end plate 23 of the fixed scroll 2 prevents the valve element 7 from protruding outward.
[0030]
The valve presser 81 is formed in an annular shape so as to contact only the outer peripheral portion of the large-diameter portion 72 so that the valve body 7 can move in the axial direction by a predetermined length, and the urging body 9 includes the valve body 7 is sandwiched between the end surface of the large-diameter portion 72 and the bottom of the cylinder 8 so that the valve body 7 is urged against the opening 24 by being pressed against the valve body 7 against the opening 24. I have to. In the present embodiment, a spring having a larger diameter than the small diameter portion 71 of the valve body 7 is used as the urging body 9, but a ring-shaped leaf spring may be used.
[0031]
Further, a space formed between the small diameter portion 71 of the valve body 7 and the inner surface of the cylinder 8 is communicated with the low pressure region via the bypass passage 25.
[0032]
Further, in order to move the valve body 7 in the axial direction, as shown in FIG. 4, the valve body 7 includes a high pressure Hp acting on the high pressure action portion 61 on the end face 73 of the valve body 7, and the valve body 7. The large-diameter portion 72 of the large-diameter portion 72 is pressed downward by the low pressure Lp acting on the high-pressure acting portion 61 side, the urging force Fs of the urging body 9, A high pressure in the high pressure chamber 41 is exerted by a low pressure Lp acting on the side, a low pressure Lp acting on the end surface of the small diameter portion 71, and an intermediate pressure Mp (or low pressure Lp) acting on the convex portion 74. When the pressure Hp is equal to or lower than the set pressure, the upward pressing force of the valve body 7 overcomes the downward pressing force, and when the high pressure Hp in the high pressure chamber 41 exceeds the set pressure, the downward pressure of the valve body 7 The urging force F of the urging body 9 so that the urging force against the vicinal force overcomes the upward urging force. And the area of the end surface D1 of the projection 73 is to set the total area D2, the passage area D3 of the opening port 24 of the end face of the small diameter portion 71 and the large diameter portion 72.
[0033]
When the high pressure discharged into the high pressure chamber 41 is equal to or lower than the set pressure, the high pressure acting on the high pressure action portion 61 is also lower than the set pressure, and the pressure acting on the high pressure action portion 61 as shown in FIG. However, since the urging force of the urging body 9 and the total pressing force of the low pressure acting on the end surfaces of the small diameter portion 71 and the large diameter portion 72 of the valve body 7 are smaller, the valve body 7 moves upward and the valve body 7 is separated from the opening 24, and the intermediate pressure chamber 51 of the compression chamber 5 is opened to the suction side low pressure region in the casing 1 through the opening 24, the cylinder 8, and the bypass passage 25. Road operation is performed.
[0034]
Further, when the high pressure discharged into the high pressure chamber 41 exceeds the set pressure, a high pressure equal to or higher than the set pressure acts on the high pressure acting portion 61, and as shown in FIG. The pressure acting on the urging body 9 is larger than the total pressing force of the urging force of the urging body 9 and the low pressure pressure acting on the end surfaces of the small diameter portion 71 and the large diameter portion 72 of the valve body 7, and acts on the high pressure acting portion 61. With the high pressure, the valve body 7 is moved downward, the convex portion 74 of the valve body 7 is seated on the opening 24 and the opening 24 is closed, and the full load operation is performed.
[0035]
In this embodiment, the set high pressure is 38K when the low pressure is 8.5K, the unload operation is performed when the low pressure is less than 38K, and the full load operation is performed at 38K or more.
[0036]
In the above embodiment, two capacity control mechanisms 6 are provided corresponding to a pair of compression chambers, but may be provided only in one compression chamber. In such a case, the pressure balance in the intermediate pressure chamber cannot be maintained, but the discharge pressure can be adjusted by increasing or decreasing the discharge pressure by the merged compressed gas, and the capacity control mechanism can be integrated into one, thus reducing the cost. It can be planned.
[0037]
【The invention's effect】
According to the first aspect of the invention, in the hermetic compressor in which the casing 1 includes the compression mechanism CF, when the high pressure pressure on the discharge side is equal to or lower than the set pressure in the compression mechanism CF, the intermediate pressure chamber 51 in the course of compression. Is provided in the suction side low pressure region, and when the discharge side high pressure exceeds the set pressure, the capacity control mechanism 6 is provided that shuts off the intermediate pressure chamber 51 during compression from the suction side low pressure region. When using an alternative chlorofluorocarbon refrigerant that causes a decrease in compression capacity when the condensation temperature increases as a refrigerant, when operating at a predetermined condensation temperature that is the rated temperature condition, that is, when the high pressure on the discharge side is less than the set pressure, The intermediate pressure chamber 51 in the middle of compression is opened to a low pressure region on the suction side to perform unloading operation. In the unloading operation state, capacity control operation is performed to obtain a predetermined compression capacity under rated temperature conditions, When operating at a condensing temperature higher than the rated temperature condition at which the capacity drops, that is, when the high pressure on the discharge side exceeds the set pressure, the intermediate pressure chamber 51 during compression is shut off from the low pressure range on the suction side Thus, the full load operation is performed, and the compression capacity can be increased even when the operation is performed at a high condensation temperature.
[0038]
According to the second aspect of the present invention, the compression mechanism CF is constituted by the fixed scroll 2 and the revolution scroll 3 that define two symmetrical compression chambers, and the capacity control mechanism 6 is provided by the intermediate pressure chambers of the respective systems. Since a pair is provided corresponding to 51, 51, the scroll-type hermetic compressor having two compression chambers is also provided with the capacity control mechanism 6 corresponding to the intermediate pressure chambers 51, 51 of each system. Therefore, the pressure in each intermediate pressure chamber 51, 51 can be increased satisfactorily without breaking the pressure balance.
[0039]
According to the first aspect of the present invention, the capacity control mechanism 6 seats and separates the valve body 7 in the opening 24 that opens the intermediate pressure chamber 51 to the suction side, and biases the valve body 7 to the anti-seat side. Since the biasing body 9 and the high-pressure action part 61 that seats the valve body 7 against the biasing body 9 when the high pressure exceeds the set pressure, the valve body 7 is The capacity control can be performed with a simple structure that is operated by the difference between the force of the urging force of 9 and the high pressure on the discharge side, and it is not necessary to arrange parts outside the compressor when performing the capacity control, The piping structure is not complicated and the number of parts is not increased, so that the cost can be reduced.
[0040]
In addition, after being left standing for a long time, such as sleeping, the pressure on the high-pressure side and the low-pressure side is in a balanced state, that is, the high pressure on the discharge side is less than the set pressure. It has become. For this reason, the liquid compression that occurs at the time of start-up of the bed is also released from the opening 24 to the low pressure range, and the liquid compression can be avoided.
[0041]
According to the third aspect of the present invention, the anti-seat side of the valve body 7 is inserted into the through-hole 43 provided in the pressure partition 4 that partitions the inside of the casing 1 into the high pressure side and the low pressure side. Since the anti-seat side end face is opened to the high pressure side to form the high pressure action part 61, the discharge gas discharged to the high pressure side in the casing 1 partitioned by the pressure partition 4 is used as the counter seat side end face of the valve body 7. When the discharge-side pressure exceeds the set pressure by acting on the high-pressure acting part 61 formed in the above, that is, when the pressure on the high-pressure side in the casing 1 becomes equal to or higher than the set pressure, Therefore, the valve body 7 can be seated on the opening 24 and the valve body 7 can be easily operated.
[Brief description of the drawings]
FIG. 1 is a partial longitudinal sectional view showing an embodiment of a hermetic compressor according to the present invention and shows a full load operation state.
FIG. 2 is a partial longitudinal sectional view of the embodiment showing an unload operation state.
FIG. 3 is a top view of the fixed scroll in the same embodiment as viewed from above, showing a state where a valve element is inserted into only one cylinder.
FIG. 4 is an explanatory view showing a state of pressure acting on a valve body in the present invention.
FIG. 5 is a partial longitudinal sectional view showing a conventional scroll compressor.
FIG. 6 is an explanatory diagram showing a state of piping connected to a conventional scroll compressor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Casing CF Compression mechanism 2 Fixed scroll 24 Opening port 3 Revolving scroll 4 Pressure partition 43 Through-hole 51 Intermediate pressure chamber 6 Capacity control mechanism 61 High pressure action part 7 Valve body 9 Energizing body

Claims (3)

In the hermetic compressor in which the casing (1) is provided with a compression mechanism (CF), the compression mechanism (CF) has a set pressure based on a condensation temperature under a rated temperature condition in which a high pressure on the discharge side is determined within a normal operation range. In the following cases, the intermediate pressure chamber (51) during compression is opened to the low pressure region on the suction side, and when the high pressure on the discharge side exceeds the set pressure, the intermediate pressure chamber (51) during compression is opened on the suction side. A capacity control mechanism (6) that cuts off the low pressure range is provided.
The capacity control mechanism (6) includes a valve body (7) seated and separated at an opening (24) that opens the intermediate pressure chamber (51) to the suction side, and the valve body (7) on the anti-seat side. An urging body (9) for urging, and a high pressure action portion (61) for seating the valve body (7) against the urging body (9) when the high pressure exceeds a set pressure ;
The high pressure acting portion (61), hermetic compressors, characterized that you exposed to the high pressure chamber (41) which compressed gas is discharged.   The compression mechanism (CF) includes a fixed scroll (2) and a revolving scroll (3) that define two symmetrical compression chambers, and the capacity control mechanism (6) includes an intermediate pressure chamber (51) of each system. The hermetic compressor according to claim 1, wherein a pair is provided corresponding to (51). The non-seat side of the valve body (7) is inserted into a through-hole (43) provided in the pressure bulkhead (4) dividing the inside of the casing (1) into a high pressure side and a low pressure side, and the valve body (7) anti seating side pressure acting portion end faces open to the high pressure side (61) and form sealed compressor according to claim 1 wherein is.

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