JP2002168175A - Linear compressor and refrigeration cycle equipment - Google Patents

Abstract

(57) [Problem] To reduce the risk of collision between a piston and a cylinder when driving a linear compressor, thereby preventing damage to parts and improving operational stability of the piston. SOLUTION: A piston ring 44a serving as a buffer means for reducing an impact force with a cylinder head 25 is provided on an outer periphery of a top end side of a piston 42 of a linear compressor, and the ring 44a partially covers an outer periphery of an upper end portion of the piston 42. It has a shape and is made of an elastic body such as a resin, and serves as a buffer means to absorb an impact force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a linear compressor for generating compressed gas by reciprocating a piston in a cylinder by a linear motor, and a refrigeration cycle apparatus using the same.

[0002]

2. Description of the Related Art Hitherto, as a means for generating compressed gas of a refrigerant, there has been known a refrigeration cycle apparatus using a linear compressor which performs gas compression by reciprocating a piston in a cylinder by a linear motor. Specific examples of the refrigeration cycle device include an air conditioner that keeps room temperature comfortably during cooling and heating, and a refrigerator that keeps room temperature properly.

Hereinafter, a conventional refrigeration cycle apparatus will be described with reference to the drawings.

FIG. 4 is a system configuration diagram in which a conventional refrigeration cycle apparatus is applied to an air conditioner.
Is a linear compressor, 2 is a four-way valve for switching a cooling and heating cycle, 3 is an outdoor heat exchanger which is a heat source side heat exchanger, 4
Reference numeral denotes an expansion valve serving as a throttle device for adjusting the amount of circulating refrigerant, and reference numeral 5 denotes an accumulator provided in the outdoor unit 6. Also,
Reference numeral 7 denotes an indoor unit provided with a room temperature detector 9 for detecting a room temperature which is an ambient temperature of an indoor heat exchanger 8 which is a load side heat exchanger. The indoor unit 7 is installed in a room 10.

[0005] The gas side and the liquid side of the outdoor unit 6 and the indoor unit 7 are respectively connected to a gas side pipe 11 and a liquid side pipe 1.
2, a pressure detector 13 is provided in the gas side pipeline 11, and a superheat degree detector 14 is attached to a suction part of the linear compressor 1. In this method, a refrigerant is sealed in a closed circuit to form a well-known heat pump cycle. The refrigerant is a single refrigerant, a mixed refrigerant (azeotropic mixed refrigerant, non-azeotropic mixed refrigerant), HFC refrigerant, natural refrigerant (HC refrigerant, CO refrigerant).
₂ refrigerant, etc.).

The operation of the refrigeration cycle apparatus according to the embodiment of the present invention in such a configuration will be described below.

During the heating operation, as shown by the solid line in FIG.
The refrigerant is compressed in the linear compressor 1, becomes high-temperature and high-pressure steam, is discharged through the four-way valve 2 to the gas pipeline 11, and reaches the indoor heat exchanger 8 in the indoor unit 7. At this time, the indoor heat exchanger 8 functions as a condenser, heats the room 10 by applying heat to the air in the room 10, and condenses the refrigerant. The liquefied refrigerant passes through the liquid side pipe 12 and the expansion valve 4 and reaches the outdoor heat exchanger 3. In such a case, the outdoor heat exchanger 3
Works as an evaporator, and the refrigerant receives heat from the outside air and evaporates, becomes low-pressure steam, and is sucked into the linear compressor 1 through the four-way valve 2 and the accumulator 5.

During the cooling operation, the outdoor heat exchanger 3 functions as a condenser and the indoor heat exchanger 8 functions as an evaporator by switching the four-way valve 2 as shown by the broken line in FIG. Then, the room 10 is cooled.

FIG. 5 is a sectional view of the linear compressor 1 used in the refrigeration cycle apparatus of FIG. A piston 21 is slidably supported on a cylinder 20a provided in a part of the closed container 20 along the axial direction thereof. Piston 2
A magnet 22 is fixed to 1. A stator coil 24 buried in the outer yoke 23 is provided at a position facing the magnet 22.

A cylinder head 25 is provided at an end of the cylinder 20a, and a space surrounded by the cylinder 20a, the piston 21 and the cylinder head 25 becomes a compression chamber 26. A suction chamber 28 to which a suction pipe 27 is connected and a discharge pipe 2 are provided on a surface of the cylinder head 25 opposite to the compression chamber 26.
Cover 31 constituting discharge chamber 30 to which nozzle 9 is connected
Is provided.

The cylinder head 25 is provided with a suction hole 32 that connects the suction chamber 28 and the compression chamber 26, and a discharge hole 33 that connects the compression chamber 26 and the discharge chamber 30. A suction valve 34 is provided in the suction hole 32, and a discharge valve 35 is provided in the discharge hole 33.
Are provided respectively. The piston 21 is a support spring 3
6 are elastically supported. In FIG. 5, magnet 2
The piston 21 reciprocates in its axial direction by intermittently energizing a linear motor 37 composed of the outer yoke 23 and the stator coil 24 via a motor driver (not shown). Inhalation of
Compression is performed.

[0012]

In the conventional refrigeration cycle apparatus having the above structure, when the input power to the linear compressor 1 increases or when the load changes, the refrigerant drawn by the linear compressor 1 is changed. When the pressure difference between the pressure (hereinafter, referred to as suction pressure) and the pressure of the refrigerant to be discharged (hereinafter, referred to as discharge pressure) decreases, the stroke of the piston 21 increases.

As described above, in the linear compressor 1 used in the refrigeration cycle apparatus, the stroke of the piston 21 changes depending on the state of input and load, and there is a risk that the piston 21 may collide with the suction valve 34 or the cylinder head 25. In particular, during the discharge stroke of discharging the refrigerant from the compression chamber 26, the piston 21 exceeds the predetermined top dead center position and the suction valve 34
Alternatively, a collision may occur with the cylinder head 25. If the collision continues to occur, the piston 21, the suction valve 34 and the cylinder head 25 are damaged, and the operation of the linear compressor 1 becomes impossible.

If the piston 21 moves too far to the bottom dead center, the control range of the electromagnetic force of the linear motor 37 is exceeded, and the operating stability of the piston decreases.

Accordingly, the present invention provides a linear compressor that prevents damage to parts by avoiding direct collision between a piston, a suction valve, and a cylinder head when the linear compressor is driven, and a refrigeration cycle apparatus using the linear compressor. And to provide.

Further, the present invention regulates the range of movement of the piston toward the bottom dead center, and prevents the piston from moving too far toward the bottom dead center and exceeding the control range of the electromagnetic force of the linear motor. Another object of the present invention is to provide a linear compressor that improves the operational stability of a piston, and a refrigeration cycle device using the linear compressor.

[0017]

According to a first aspect of the present invention, a cylinder having a cylinder head and a piston driven by a linear motor in the cylinder are provided. And a first buffer means for absorbing an impact force at the time of collision between the piston main body and the cylinder head is provided at an end of the piston at a top dead center side. is there.

Further, the second invention (corresponding to claim 2)
The first compressor according to the first aspect of the present invention is characterized in that the first buffering means is a first piston ring attached to an outer periphery of a top dead center side end of the piston.

Further, the third invention (corresponding to claim 3)
Is a linear compressor according to a second aspect of the present invention, wherein the first piston ring has a shape that covers at least the outer periphery of the top dead center side end of the piston.

A fourth aspect of the present invention (corresponding to claim 4)
Is characterized in that a projection is provided on the inner periphery of the cylinder at a position corresponding to the bottom dead center of the piston to interfere with the bottom dead center side end of the piston. A linear compressor according to any of the present inventions.

Further, a fifth aspect of the present invention (corresponding to claim 5)
According to a fourth aspect of the present invention, there is provided a second shock absorbing means for absorbing an impact force at the time of collision between the piston main body and the projection at a bottom dead center side end of the piston. Is a linear compressor.

The sixth invention (corresponding to claim 6)
The fifth aspect of the present invention is the linear compressor according to the fifth aspect of the present invention, wherein the second buffer means is a second piston ring attached to an outer periphery of a lower dead end of the piston.

Further, a seventh aspect of the present invention (corresponding to claim 7)
The sixth aspect of the present invention is the linear compressor according to the sixth aspect, wherein the second piston ring has a shape that covers at least an outer periphery of a bottom dead center side end of the piston.

The eighth invention (corresponding to claim 8)
Is a linear compressor according to any one of the first to third aspects of the present invention, wherein the first buffer means is made of an elastic body.

A ninth aspect of the present invention (corresponding to claim 9)
The first piston ring is a tubular ring in which the inside of a ring-shaped tube is cut open around the circumference and is open, and a part of the first piston ring is located around the top dead center side edge of the open ring. A linear compressor according to a second aspect of the present invention, wherein a diameter of the ring is larger than a diameter of a circumference of a lower dead end side edge of the ring.

According to a tenth aspect of the present invention (corresponding to claim 10), a groove for locking the first piston ring is formed on the outer periphery of the upper dead end of the piston. A ninth aspect of the present invention is the linear compressor according to the ninth aspect, wherein the piston is formed such that a gap exists between at least a central portion in the axial direction of the piston and an inner periphery of the cylinder.

[0027] According to an eleventh aspect of the present invention (corresponding to claim 11), the second piston ring is a tubular ring in which the inside of a ring-shaped tube is cut open over one circumference and is opened. A linear structure according to a sixth aspect of the present invention, wherein the diameter of the circumference of the bottom dead center side edge of the partially opened ring is larger than the circumference of the top dead center side edge of the ring. It is a compressor.

A twelfth invention (corresponding to claim 12) is a refrigeration cycle apparatus comprising the linear compressor according to any one of the first to eleventh inventions.

The thirteenth invention (corresponding to claim 13) is the refrigeration cycle apparatus according to the twelfth invention, wherein a CO ₂ refrigerant is used as the refrigerant.

[0030]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a linear compressor 41 according to Embodiment 1. The linear compressor 41 according to Embodiment 1 of the present invention has substantially the same configuration as the conventional linear compressor described with reference to FIG. 5, and the same parts are denoted by the same reference numerals. FIG. 2 is a cutaway perspective view of the piston rings 44a and 44b according to the first embodiment.

In the first embodiment of the present invention, as shown in FIG. 1, two grooves 43a are formed on the outer circumference near the top dead center side end 42a of the piston 42 and near the bottom dead center side end 42b. ,
43b are formed in these grooves, and conical ring-shaped piston rings 44a,
4b, the small-diameter end 45 (see FIG. 2)
3a and 43b are attached so as to be in close contact with the bottom surface.

The lower end 42 of the piston 42 is provided on the inner surface of the cylinder 20a near the bottom dead center of the piston 42.
A piston stopper 20b, which is an inward projection that interferes with b, is provided.

As shown in FIG. 2, each of the piston rings 44a, 44b has a smaller diameter d at the small diameter end 45 at one end in the axial direction than a diameter D at the large diameter end 46 at the other end.
An outer peripheral surface between the large-diameter end 46 and the large-diameter end 46 is formed by an outwardly convex curved surface 47, and the large-diameter end 46 partially covers the top dead center side end 42 a or the bottom dead center side end 42 b of the piston 42. And a notch 49 is provided in the flange portion 48.

The piston rings 44a and 44b will be further described. The piston ring is a ring in which the inner circumference of a ring-shaped tube is cut out over one circumference, and the cut-out portion is opened. The opening is used to attach to the piston 42. The large-diameter end 46 means the circumference of one axial end of the piston ring, and the small-diameter end 45 means the circumference of the other axial end of the piston ring.

This conical ring type piston ring 44a,
44b is, for example, polytetrafluoroethylene (PTF
E) It is made of an elastic material such as resin. The piston rings 44a and 44b have the large diameter end 46 directed toward the top dead center and the bottom dead center, respectively.
Also, the flange 48 is disposed so as to partially cover the bottom dead center side end 42b.

The diameter of the small diameter end 45 of each of the piston rings 44a, 44b is configured to be smaller than the diameter of the bottom surface of the two grooves 43a, 43b. Therefore, when mounting the piston rings 44a, 44b in the grooves 43a, 43b of the piston 42, the piston rings 44a, 44b
Is elastically deformed to the diameter of the bottom surface of the grooves 43a, 43b. Therefore, the piston rings 44a, 44
A tightening force acts between the small-diameter end 45b and the bottom surfaces of the grooves 43a and 43b, and sufficient adhesion is obtained.

Next, the operation of the linear compressor 41 having the above configuration will be described. The piston 42 reciprocates by the electromagnetic force of the linear motor 37. When the piston 42 moves from the top dead center side (left side in FIG. 1) to the bottom dead center side (right side in FIG. 1), the discharge valve 35 provided in the discharge hole 33 and the suction valve 34 provided in the suction hole 32 Is closed and the compression chamber 26
The pressure in the compression chamber 26 becomes equal to or lower than the suction pressure, and the suction valve 34 provided in the suction hole 32 is opened to increase the volume of the compression chamber 26.
Performs a suction stroke in which the refrigerant is sucked from the pump.

When the piston 42 moves from the bottom dead center side (the right side in FIG. 1) to the top dead center side (the left side in FIG. 1), the piston 42 is provided in the discharge valve 35 provided in the discharge hole 33 and the suction hole 32. The suction valve 34 is closed and the refrigerant is compressed as the volume of the compression chamber 26 decreases. Subsequently, the pressure in the compression chamber 26 becomes higher than the discharge pressure, and the discharge valve 35 provided in the discharge hole 33 opens, and the refrigerant is discharged. The discharge process of discharging is performed.

The stroke of the piston 42 increases when the input power to the linear compressor 41 increases or when the load changes and the pressure difference between the pressure of the refrigerant sucked by the linear compressor 41 and the pressure of the discharged refrigerant decreases. .

In the present embodiment, the piston ring 44a
Is formed so as to partially cover the top dead center side end 42a of the piston 42, and the piston ring 44a is made of an elastic body, so that the piston 42 and the suction valve 34 or the cylinder head 25 are in the discharge stroke. When a collision occurs, the flange portion 48 of the piston ring 44a serves as a shock absorbing means and absorbs an impact force.
4 or the cylinder head 25 can be prevented from being damaged.

Further, since the piston 42 is provided with the piston stopper 20b on the inner surface of the cylinder 20a near the bottom dead center of the piston 42, the piston 42 moves too much to the bottom dead center side and exceeds the control range by the electromagnetic force of the linear motor 37. Can be prevented.

Further, the flange portion 48 of the piston ring 44b is formed so as to partially cover the lower end side end portion 42b of the piston 42, and the piston ring 44b is made of an elastic material. When the piston stopper 20b collides, the flange portion 48 of the piston ring 44b serves as a buffer means to absorb the impact force, so that the piston 42 and the piston stopper 20b can be prevented from being damaged.

Further, the use of the conical ring-shaped piston rings 44a, 44b having the outwardly convex curved surface 47 prevents the contact between the cylinder 20a and the edge of the large-diameter end 46 of the piston rings 44a, 44b. Since the convex curved surfaces 47 of 44a and 44b come into surface contact with the inner surface of the cylinder 20a, the contact surface pressure is reduced, and wear of the inner surface of the cylinder 20a and the piston rings 44a and 44b can be reduced.

The large-diameter end 46 of the piston ring 44a
Is arranged toward the top dead center side, a notch 49 is provided in a flange portion 48 of the piston ring 44a covering the top dead end side 42a of the piston 42, and the small diameter end 45 of the piston ring 44a is By adhering to the bottom surfaces of the grooves 43a and 43b, the refrigerant gas in the compression chamber 26 is transferred to the inner peripheral surface side of the piston ring 44a while preventing leakage of the refrigerant from the compression chamber 26 by the small diameter end 45 of the piston ring 44a. Can be guided to the cylinder 20a of the piston ring 44a.
The contact pressure on the wall can be obtained to improve the sealing performance. In particular, when a CO ₂ refrigerant having a high pressure difference is used as the refrigerant, the sealing ability is significantly improved, which is more effective.

Further, the lower dead end 42b of the piston 42
Is also provided in the vicinity of the piston ring 44b,
An intermediate pressure between the suction pressure and the discharge pressure is generated between the two piston rings 44a and 44b, and a two-stage seal with less leakage can be performed, so that the sealing performance can be improved. In particular, when a CO ₂ refrigerant having a high pressure difference is used as the refrigerant, the sealing ability is significantly improved, which is more effective.

Further, the upper end 42a of the piston 42 on the top dead center side
The piston rings 44a and 44b are provided near the bottom end and the bottom dead center side end 42b, respectively.
Even when the piston 42 is tilted due to the side pressure generated on the outer peripheral surface of the second 2, wear due to direct contact between the piston 42 and the cylinder 20a can be prevented.

In the above-described embodiment, the piston ring 44a is used as the shock absorbing means for absorbing the impact force at the time of collision between the piston 42 main body and the cylinder head 25, but the shock absorbing means is limited to the piston ring 44a. Not something. For example, a buffering unit made of an elastic material such as resin may be arranged on all or a part of the outer peripheral portion of the end surface on the top dead center side of the piston 42, and may be used as a substitute for the piston ring 44a. In short, the piston 42 body and the cylinder head 25
What is necessary is just to provide a buffer means for absorbing the impact force at the time of collision with the vehicle.

In the above-described embodiment, the piston ring 44b is used as the second buffer means for absorbing the impact force at the time of collision between the piston 42 main body and the piston stopper 20b. It is not limited to 44b. For example, a buffer means made of an elastic material such as resin is arranged on all or a part of the outer peripheral portion of the lower dead end side end surface of the piston 42,
It may be used as a substitute for b. In short, piston 42
At the bottom dead center side end portion, it is only necessary to provide the second buffer means for absorbing the impact force at the time of collision between the piston 42 main body and the piston stopper 20b.

Also, as shown in FIG.
Is formed so that a gap exists between the axial center portion and the inner periphery of the cylinder 20a, whereby the axial center portion of the piston 42 and the inner periphery of the cylinder 20a are formed. Since the frictional force stops working, the efficiency increases and the reliability improves.

(Embodiment 2) FIG. 3 is a system configuration diagram in which a refrigeration cycle apparatus according to Embodiment 2 is applied to an air conditioner. In FIG. 3, reference numeral 41 denotes a linear compressor of the first embodiment, and the other configuration is the same as that of the conventional refrigeration cycle apparatus shown in FIG. Therefore, similar parts are denoted by the same reference numerals.

As described above, in the linear compressor 41 of the first embodiment, damage due to collision between the piston 42 and the suction valve 34 or the cylinder head 25 is prevented, and damage due to collision between the piston 42 and the piston stopper 20b is prevented. In addition, it is possible to prevent the electromagnetic force of the linear motor 37 from exceeding the control range,
The wear of the inner surfaces of the piston rings 44a and 44b is reduced, the contact pressure of the piston ring 44a with the wall of the cylinder 20a is improved to improve the sealing performance. Improve
Since wear due to direct contact between the piston 42 and the cylinder 20a can be prevented, the reliability and efficiency of the linear compressor 41 can be improved.

Therefore, it goes without saying that the refrigeration cycle apparatus shown in FIG. 3 using the linear compressor 41 has high reliability and efficiency. In particular, C, which has a high pressure difference as a refrigerant
When the O ₂ refrigerant is used, the sealing ability between the cylinder 20a and the piston 42 of the linear compressor 41 is remarkably improved, which is more effective.

[0054]

As described above, the present invention provides a linear compressor which prevents damage to parts by avoiding a direct collision between a piston, a suction valve and a cylinder head when the linear compressor is driven, and a linear compressor having the same. A refrigeration cycle device using a linear compressor can be provided.

Further, the present invention regulates the range of movement of the piston toward the bottom dead center, thereby preventing the piston from moving too far toward the bottom dead center and exceeding the control range of the linear motor by the electromagnetic force. In addition, it is possible to provide a linear compressor that improves the operational stability of the piston, and a refrigeration cycle device using the linear compressor.

That is, the present invention can provide a linear compressor with high reliability and stability and a refrigeration cycle apparatus using the same.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a linear compressor according to a first embodiment of the present invention.

FIG. 2 is a cutaway perspective view of a piston ring which is a component of the first embodiment of the present invention.

FIG. 3 is a system configuration diagram of a refrigeration cycle apparatus according to Embodiment 2 of the present invention.

FIG. 4 is a system configuration diagram of a conventional refrigeration cycle device.

FIG. 5 is a sectional view of a conventional linear compressor.

[Explanation of symbols]

 1, 41 Linear compressor 20 Airtight container 20a Cylinder 20b Piston stopper 21, 42 Piston 25 Cylinder head 26 Compression chamber 34 Suction valve 35 Discharge valve 37 Linear motor 44a, 44b Piston ring 48 Flange 49 Notch

Continued on the front page (72) Inventor Fumitoshi Nishiwaki 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. 3H076 AA02 BB26 BB28 BB43 CC06 CC28 CC31 CC92 CC93

Claims (13)

[Claims] At least a cylinder having a cylinder head and a piston driven by a linear motor in the cylinder are provided at a top dead center side end of the piston.
A linear compressor having a first buffering means for absorbing an impact force at the time of collision between the piston body and the cylinder head. 2. The linear compressor according to claim 1, wherein the first shock-absorbing means is a first piston ring attached to an outer periphery of a top dead center side end of the piston. 3. The linear compressor according to claim 2, wherein the first piston ring has a shape covering at least an outer periphery of a top dead center side end of the piston. 4. A projection that interferes with a bottom dead center side end of the piston is provided on an inner periphery of the cylinder at a position corresponding to the bottom dead center of the piston. 4. The linear compressor according to any one of claims 1 to 3. 5. A second shock absorbing means for absorbing an impact force at the time of collision between the piston body and the projection is provided at an end of the piston at a bottom dead center side.
The linear compressor according to 1. 6. The linear compressor according to claim 5, wherein the second buffering means is a second piston ring attached to an outer periphery of a lower dead end of the piston. 7. The linear compressor according to claim 6, wherein the second piston ring has a shape that covers at least the outer circumference of a bottom dead center side end of the piston. 8. The linear compressor according to claim 1, wherein said first buffer means is made of an elastic body. 9. The first piston ring is a tubular ring in which the inside of a ring-shaped tube is cut open around the entire circumference thereof and is open, and a part of the ring is open at the top dead center side edge. 3. The linear compressor according to claim 2, wherein a diameter of a circumference of the ring is larger than a diameter of a circumference of an end edge on a bottom dead center side of the ring. 10. A groove for locking the first piston ring is formed on the outer periphery of the top dead center side end of the piston, and at least a central portion of the piston in the axial direction and the inside of the cylinder are formed. The linear compressor according to claim 9, wherein the piston is formed such that a gap exists between the piston and the periphery. 11. The second piston ring is a tubular ring in which the inside of a ring-shaped pipe is cut open around the circumference thereof and is open, and a part of the ring is opened and the bottom dead center side edge thereof. 7. The linear compressor according to claim 6, wherein the diameter of the circumference of the ring is larger than the diameter of the circumference of the edge at the top dead center side of the ring. 12. A refrigeration cycle apparatus comprising the linear compressor according to any one of claims 1 to 11. 13. The refrigeration cycle apparatus according to claim 12, wherein a CO ₂ refrigerant is used as the refrigerant.