JP2002317761A - Linear compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem on a spring to be used for a linear compressor that a great allowable deflection amount and a high spring constant should be achieved in a compact construction and high reliability should be established even in use for a refrigeration cycle with a high differential pressure. SOLUTION: This linear compressor comprises, at least, a cylinder, a piston fitted with the cylinder to form a compression chamber, a linear motor for reciprocating the piston in the axial direction of the cylinder. A plate spring and a coil spring are used for supporting the piston so as to be reciprocative in the axial direction of the cylinder, thereby compatibly achieving a great deflection amount and a high spring constant in a compact construction and establishing high reliability and high efficiency even in use for the refrigeration cycle with a high differential pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear compressor for air conditioning and refrigeration which generates a compressed gas by reciprocating a piston in a cylinder by a linear motor.

[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 for performing 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 the inside temperature of the refrigerator properly.

Hereinafter, a conventional linear compressor will be described with reference to the drawings.

FIG. 6 is a sectional view of a conventional linear compressor, in which a compression mechanism 2 is elastically supported by vibration isolating springs 3a and 3b inside a closed container 1. The structure of the compression mechanism 2 is such that a piston 5 is fitted into a cylinder 4, and a resonance spring 6 composed of a plurality of leaf springs 6a, 6b, 6c is attached to the piston 5.
Thus, it is elastically supported so as to be able to reciprocate in the axial direction of the cylinder 4.

[0005] A cylindrical magnet holder 7 is connected to the piston 5, and a magnet 8 is fixed to the cylindrical surface of the magnet holder 7. An inner yoke 9 and an outer yoke 10 are arranged so as to sandwich the cylindrical surface of the magnet holder 7 holding the magnet 8, and a stator coil 11 is embedded at a position of the inner yoke 9 facing the magnet 8. . The portion composed of the mag holder 7, the magnet 8, the inner yoke 9, the outer yoke 10, and the stator coil 11 is called a linear motor 12.

The lower yoke side end surface of the outer yoke 10 is a pedestal for the resonance spring 6. A base plate 13 is disposed on the end surface of the resonance spring 6 on the side opposite to the outer yoke 10, and the base plate 13 is connected to the vibration-proof springs 3a, 3a.
b. A cylinder head 14 is provided on an end surface of the cylinder 4, and a space surrounded by the cylinder 4, the piston 5, and the cylinder head 14 serves as a compression chamber 15.

[0007] The closed vessel 1 is provided with a suction pipe 16. On the surface of the cylinder head 14 opposite to the compression chamber 15, a discharge chamber 1 to which a suction chamber 17 and a discharge pipe 18 are connected is provided.
9 is provided. The cylinder head 14 is provided with a suction hole 21 communicating the suction chamber 17 and the compression chamber 15 and a discharge hole 22 communicating the compression chamber 15 and the discharge chamber 19. A suction valve 23 is provided in the suction hole 21, and a discharge valve 24 is provided in the discharge hole 22.

Next, the operation of the conventional linear compressor having the above configuration will be described.

When a current is supplied to the stator coil 11 of the linear motor 12 via a motor driver (not shown), the movable portion 25 including the piston 5, the mag holder 7 and the magnet 8 reciprocates in the axial direction.

When the movable part 25 including the piston 5 moves from the top dead center side to the bottom dead center side, the discharge valve 24 provided in the discharge hole 22 and the suction valve 23 provided in the suction hole 21 are closed. The expansion process in which the refrigerant in the compression chamber 15 is decompressed and expanded, and then the pressure in the compression chamber 15 becomes equal to or lower than the suction pressure, the suction valve 23 provided in the suction hole 21 is opened, and the capacity of the compression chamber 15 increases. Performs a suction stroke in which the refrigerant is sucked.

When the movable portion 25 including the piston 5 moves from the bottom dead center side to the top dead center side, the discharge valve 24 provided in the discharge hole 22 and the suction valve 23 provided in the suction hole 21 close. A compression process is performed in which the refrigerant is compressed as the volume of the compression chamber 15 decreases, and then a discharge process in which the pressure in the compression chamber 15 becomes equal to or higher than the discharge pressure and the discharge valve 24 provided in the discharge hole 22 is opened to discharge the refrigerant. .

Next, the flow of the refrigerant gas will be described.
The refrigerant gas from the refrigeration cycle (not shown) is supplied to the suction pipe 1
After being once opened to the internal space of the sealed container 1 from 6, the air is guided to the suction chamber 17 in the head cover 20, and reaches the compression chamber 15 via the suction hole 21 provided in the cylinder head 14. The refrigerant gas that has reached the compression chamber 15 is compressed by the reciprocating motion of the movable part 25 including the piston 5 described above. The compressed refrigerant gas is once discharged through a discharge hole 22 provided in the cylinder head 14 to a discharge chamber 19 in the head cover 20.
Is discharged to the refrigeration cycle from the discharge pipe 18.

Next, the role of the resonance spring 6 will be described. As described above, the movable portion 25 is driven and reciprocated by energizing the linear motor 12 via a motor driver (not shown), but the kinetic energy of the movable portion 25 is resonated by using the resonance spring 6. It can be replaced by the elastic energy of the spring 6 and taken out again as the kinetic energy of the movable part 25 when moving in the opposite direction. Therefore, it is possible to prevent energy loss when the direction of the movement of the movable section 25 is changed due to the reciprocating movement, and efficiently move the movable section 2.
5 can be reciprocated.

At this time, by making the frequency of the reciprocating motion of the movable portion 25 coincide with the resonance frequency determined by the spring constant of the movable portion 25 and the resonance spring 6 and the gas spring constant of the compression chamber 15, a smaller linear motor 12 With thrust,
It is possible to take a larger stroke of the reciprocating motion of the movable portion 25, and it is possible to make the movable portion 25 reciprocate more efficiently.

The pressure in the compression chamber 15 acts on the end face of the piston 5 on the top dead center side, and the internal pressure of the sealed container 1 acts on the end face on the bottom dead center side. Considering the time average, the differential pressure due to the average pressure of the compression chamber 15 and the internal pressure of the closed vessel 1 is always acting, and the differential pressure causes the piston 5 to receive the differential pressure toward the bottom dead center. Will be. By using the resonance spring 6, the vibration center position of the resonance spring 6 is automatically offset so as to generate an elastic force balanced with the differential pressure, so that the differential pressure can be apparently ignored. Accordingly, since a load due to the differential pressure is not applied to the linear motor 12, the amount of current supplied from the motor driver (not shown) to the stator coil 11 can be reduced, and the efficiency of the linear compressor can be improved.

[0016]

In the conventional linear compressor having the above-described structure, a refrigeration cycle apparatus having a large differential pressure, particularly, a refrigerant Freon R410A.
When used in a refrigeration cycle using carbon dioxide, which is a natural refrigerant, the resonance spring requires a large elastic force because the differential pressure acting on the piston becomes extremely large. In addition, it is required to replace the kinetic energy of the movable part composed of the piston, the mag holder, and the magnet as the elastic force. Therefore, the resonance spring requires a large allowable deflection and a large spring constant (elastic force per unit deflection).

In the conventional linear compressor, a leaf spring is used as a resonance spring. As for the leaf spring, when the spring constant per sheet is increased, the allowable deflection decreases, and conversely, when the allowable deflection required as a linear compressor is secured, the spring constant decreases. Therefore, in order to secure an allowable deflection determined by the stroke of the piston necessary to obtain a predetermined refrigeration capacity, the spring constant per piece is reduced,
In order to meet the required elastic force of the linear compressor, multiple sheets were used.

However, when the differential pressure of the refrigeration cycle suddenly increases, the leaf spring may exceed the allowable deflection and break, making it difficult to ensure reliability. Further, if the spring constant per leaf spring is further reduced in order to prevent such breakage, the number of leaf springs for obtaining the elastic force required for the linear compressor increases exponentially, resulting in a compact size. Configuration becomes difficult.
Therefore, it has been desired to obtain a larger piston stroke without lowering the spring constant of the leaf spring, and to prevent breakage of the leaf spring to ensure reliability.

When a coil spring is used as the resonance spring, a configuration is used in which two coil springs are combined to apply a preload that compresses each other in order to prevent the coil spring from rattling in the axial direction. In this case, since two coil springs that are larger in the axial direction than the leaf spring are used, it is difficult to have a compact configuration as compared with the case where the leaf spring is used. In addition, the leaf spring has a restraining force in a direction perpendicular to the axis, while the coil spring has a weak restraining force in a direction perpendicular to the axis,
When a compressive force is received, a side force that escapes to the side is generated. For this reason, a frictional force is generated by the side force on the sliding surface between the piston and the cylinder elastically supported by the resonance spring, which is disadvantageous in terms of efficiency and reliability.

Therefore, the present invention solves the above-mentioned conventional problems, and by using a coil spring and a leaf spring together,
A spring constant that enables a larger piston stroke to be obtained with the same leaf spring as before, prevents the coil spring and the leaf spring from bending beyond the allowable deflection amount, and obtains a necessary elastic force. To provide a highly reliable linear compressor by ensuring a stable construction and not generating a side force on the sliding surface between the piston and the cylinder, and at the same time, by making them compact as in the past. With the goal.

[0021]

In order to solve the above-mentioned problems, a first invention (corresponding to claim 1) comprises a cylinder, a piston which is fitted with the cylinder to form a compression chamber, and a piston. And a linear motor for reciprocating the piston in the axial direction of the cylinder, and supporting the piston reciprocally in the axial direction of the cylinder using a leaf spring and a coil spring.

The second invention (corresponding to claim 2)
Wherein the coil spring is installed so as to be compressed when the piston moves to the bottom dead center side.
Is a linear compressor according to the present invention.

The third invention (corresponding to claim 3)
Is a linear compressor according to the first or second aspect of the present invention, wherein the leaf spring and the coil spring apply a preload to each other during assembly.

The fourth invention (corresponding to claim 4)
Wherein the amount of deflection of the leaf spring when the coil spring is compressed to a close contact height falls within the allowable deflection of the leaf spring. It is a linear compressor.

The fifth invention (corresponding to claim 6)
Is a linear compressor according to any one of the first to fourth aspects of the present invention, wherein the coil spring is arranged on an outer peripheral side of the piston.

The sixth invention (corresponding to claim 5)
Is a linear compressor according to any one of the first to fourth aspects of the present invention, wherein the coil spring is disposed inside the piston.

The seventh invention (corresponding to claim 7)
Is a linear compressor according to any one of the first to fourth aspects of the present invention, wherein the coil spring is arranged on a side of the plate spring opposite to the piston.

The eighth invention (corresponding to claim 8)
Is a linear compressor according to any one of the first to seventh aspects of the present invention, which operates using a refrigerant containing carbon dioxide as a main component.

[0029]

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 according to Embodiment 1, and FIG. 2 shows a state in which a piston 35 has moved to the top dead center side in the linear compressor according to Embodiment 1. FIG. 3 is a cross-sectional view of the linear compressor according to Embodiment 1 in a state where the piston 35 has moved to the bottom dead center side and the coil spring 36 has been compressed to the close contact height.

Referring to FIGS. 1 to 3, a compression mechanism 32 is elastically supported by vibration isolating springs 33a and 33b inside a closed container 31. The configuration of the compression mechanism 32 is such that a piston 35 is fitted into the cylinder 34, and a seat surface 34 a facing the top dead center side is provided on the inner peripheral side of the cylinder 34.
Is provided with a seat surface 35a facing the bottom dead center side, and a coil spring 36 is arranged on the outer peripheral side of the piston 35 therebetween. With such a configuration, when the piston 35 moves to the bottom dead center side, the coil spring 36 is compressed.

Incidentally, the seat surface 34a is provided with the piston 35 at the time of assembly.
And the coil spring 36 is detachable from the cylinder 34 so that the coil spring 36 can be attached to the inner peripheral side of the cylinder 34.

A leaf spring 37 is attached to the bottom end surface of the piston 35 at the bottom dead center side.
6 and a resonating spring 38 composed of a leaf spring 37 is elastically supported so as to reciprocate in the axial direction of the cylinder 34.

At the time of assembly, the coil spring 36 is compressed from its free length, the leaf spring 37 is bent toward the top dead center, and the coil spring 36 and the leaf spring 37 are The preload by the elastic force is configured to be applied to each other.

Even when the piston 35 moves to the top dead center side as shown in FIG. 2 and the end surface of the piston 35 moves to the position where it comes into contact with the cylinder head 46, the coil spring 36 still has the compression deflection. And the amount of deflection of the leaf spring 37 toward the top dead center is within the range of the allowable amount of deflection.

The coil spring 36 is configured so as to be within the range of the allowable deflection even when compressed to the close contact height, and the piston moves to the bottom dead center side as shown in FIG. Is configured such that the amount of flexure of the leaf spring 37 toward the bottom dead center falls within the range of the allowable flexure amount even when is compressed to the landing height.

The piston 35 has a cylindrical mag holder 3
The magnet 9 is fixed to the cylindrical surface of the mag holder 39. An inner yoke 41 and an outer yoke 42 are arranged so as to sandwich the cylindrical surface of the mag holder 39 holding the magnet 40, and a stator coil 43 is embedded at a position of the inner yoke 41 facing the magnet 40. . In addition,
Mag holder 39, magnet 40, inner yoke 4
1, a portion composed of the outer yoke 42 and the stator coil 43 is referred to as a linear motor 44.

The lower yoke side end surface of the outer yoke 42 is a pedestal for the leaf spring 37. A base plate 45 is disposed on an end surface of the leaf spring 37 on the side opposite to the outer yoke 42.
It is a pedestal of 33b.

The end face of the cylinder 34 has a cylinder head 4
6 is provided, and a space surrounded by the cylinder 34, the piston 35, and the cylinder head 46 becomes a compression chamber 47. The closed container 31 is provided with a suction pipe 48. A suction chamber 49 is provided on the surface of the cylinder head 46 opposite to the compression chamber 47.
And a head cover 52 forming a discharge chamber 51 to which the discharge pipe 50 is connected. The cylinder head 46 is provided with a suction hole 53 communicating the suction chamber 49 and the compression chamber 47 and a discharge hole 54 communicating the compression chamber 47 and the discharge chamber 51. A suction valve 55 is provided in the suction hole 53, and a discharge valve 56 is provided in the discharge hole 54.

Next, the operation of the linear compressor of the present invention having the above configuration will be described.

When a current is supplied to the linear motor 44 via a motor driver (not shown), a movable portion 57 comprising the piston 35, the mag holder 39 and the magnet 40 is provided.
Reciprocate in the axial direction.

When the movable part 57 including the piston 35 moves from the top dead center side to the bottom dead center side, the discharge valve 56 provided in the discharge hole 54 and the suction valve 55 provided in the suction hole 53 are closed. The expansion process in which the refrigerant in the compression chamber 47 is decompressed and expanded, and subsequently the pressure in the compression chamber 47 becomes equal to or lower than the suction pressure, the suction valve 55 provided in the suction hole 53 opens, and the capacity of the compression chamber 47 increases. Performs a suction stroke in which the refrigerant is sucked.

When the movable portion 57 including the piston 35 moves from the lower side to the upper side, the discharge valve 56 provided in the discharge hole 54 and the suction valve 55 provided in the suction hole 53 close, and the volume of the compression chamber 47 is reduced. As the pressure decreases, the compression process in which the refrigerant is compressed, and then the pressure in the compression chamber 47 becomes equal to or higher than the discharge pressure, the discharge valve 56 provided in the discharge hole 54 opens, and the discharge process in which the refrigerant is discharged is performed.

Next, the flow of the refrigerant gas will be described.
The refrigerant gas from the refrigeration cycle (not shown) is supplied to the suction pipe 4
After being once opened to the internal space of the sealed container 31 from 8, the air is guided to the suction chamber 49 in the head cover 52 and reaches the compression chamber 47 via the suction hole 53 provided in the cylinder head 46. The refrigerant gas that has reached the compression chamber 47 is compressed by the reciprocating motion of the movable portion 57 including the piston 35 described above. The compressed refrigerant gas is temporarily discharged through the discharge holes 54 provided in the cylinder head 46 to the discharge chamber 5 in the head cover 52.
After being discharged to 1, the liquid is discharged from the discharge pipe 50 to the refrigeration cycle.

Next, the resonance spring 38 including the coil spring 36 and the leaf spring 37 will be described. These perform the same role as the resonance spring 6 of the conventional linear compressor shown in FIG. That is, as described above, the movable portion 57 is driven and reciprocated by energizing the linear motor 44 via a motor driver (not shown), but the movable portion 57 is moved by using the coil spring 36 and the leaf spring 37. The kinetic energy of 57 can be replaced by the elastic energy of the coil spring 36 and the leaf spring 37, and can be taken out again as the kinetic energy of the movable portion 57 when moving in the opposite direction.
Therefore, it is possible to prevent energy loss when the direction of the movement of the movable part 57 changes with the reciprocating movement, and to make the movable part 57 reciprocate efficiently.

At this time, the frequency of the reciprocating motion of the movable portion 57 is made smaller by matching the resonance frequency determined by the spring constant of the movable portion 57, the coil spring 36 and the leaf spring 37, and the gas spring constant of the compression chamber 47. With the thrust of the linear motor 44, it is possible to take a larger stroke of the reciprocating motion of the movable portion 57, and it is possible to make the movable portion 57 reciprocate more efficiently.

The pressure in the compression chamber 47 acts on the end face on the top dead center side of the piston 35, and the internal pressure of the closed vessel 31 acts on the end face on the bottom dead center side. Considering the time average, the compression chamber 47
And the pressure difference between the internal pressure of the closed container 31 and the internal pressure of the closed vessel 31 always acts.
Is receiving a differential pressure toward the bottom dead center. By using the coil spring 36 and the plate spring 37, the vibration center positions of the coil spring 36 and the plate spring 37 are automatically offset so as to generate an elastic force balanced with the differential pressure. Can be ignored. Accordingly, since a load due to the differential pressure is not applied to the linear motor 44, the amount of electricity supplied from the motor driver (not shown) to the stator coil 43 can be reduced, and the efficiency of the linear compressor can be improved.

In this embodiment, since the coil spring 36 and the leaf spring 37 are used in combination, even if the respective spring constants are reduced and the allowable deflection is increased, the total spring of the coil spring 36 and the leaf spring 37 is increased. The constant can be increased, and the spring constant required for the linear compressor can be easily secured.

Further, by making the spring constant of the coil spring 36 larger than the spring constant of the leaf spring 37, the allowable deflection of the leaf spring 37 can be further increased, and the reliability can be improved.

Instead of the leaf spring 37, a plurality of leaf springs 6a, like a conventional linear compressor shown in FIG.
6b, 6c, the leaf springs 6a, 6b, 6c
Can be increased.

As described above, the resonance spring 38 can satisfy the contradictory requirement of increasing the spring constant while increasing the allowable deflection amount. When the stroke of the piston 35 is increased, the amount of circulating refrigerant is increased. However, the reliability of the resonance spring 38 can be improved.

Further, by using the coil spring 36 and the leaf spring 37 together, the weakness of the restraining force in the direction perpendicular to the axis, which is a drawback of the coil spring 36, can be compensated for by the leaf spring. The frictional force due to the side force acting on the sliding surface between the elastically supported piston 35 and the cylinder 34 can be minimized, and the efficiency and reliability can be improved.

The coil spring 36 is used together with the leaf spring 37 so that the coil spring 36 is compressed when the piston 35 moves to the bottom dead center side. To give each other,
Even when the top dead center end surface of the piston 35 moves to a position where it comes into contact with the cylinder head 46, the coil spring 36 is configured to have a compression deflection, and even if the coil spring 36 is compressed to the close contact height, the allowable deflection is maintained. With such a configuration, the coil spring 36 always receives an allowable range of compressive deflection within the movable range from the top dead center to the bottom dead center of the piston 35, and can be used with a single swing. Therefore, the reliability of the coil spring 36 can be improved.

The coil spring 36 is used together with the leaf spring 37 so that the coil spring 36 is compressed when the piston 35 moves to the bottom dead center side. , The amount of deflection toward the top dead center is given to the leaf spring 37 in advance, and the apparent amount of deflection toward the bottom dead center increases. Therefore, even when the same leaf spring 37 is used, the allowable stroke of the piston 35 can be increased, and the reliability of the leaf spring 37 can be improved.

Further, the coil spring 36 and the plate spring 37 are used in combination so that the coil spring 36 and the plate spring 37 apply a preload to each other during assembly.
6 and the pedestal 34a on the inner periphery of the cylinder 34 and the piston 3
5 can be improved by the elastic force due to the preload of the coil spring 37, and when the movable part 57 reciprocates, the coil spring 36 becomes the pedestals 34a, 35a.
From the pedestals 34a, 35
a, it is possible to prevent collision with the pedestals 34a, 35a again, prevent damage to the coil spring 36 and the pedestals 34a, 35a, and improve reliability. , 35a can be prevented.

Further, even when the piston 35 moves to the top dead center side as shown in FIG. 2 and the piston 35 comes into contact with the cylinder head 46, the leaf spring 37 does not exceed the allowable deflection range, and FIG. As described above, even when the piston 35 moves to the bottom dead center side and the coil spring 36 is compressed to the close contact height, the leaf spring 37 does not exceed the allowable deflection range, thereby improving the reliability of the leaf spring 37. Can be done.

The effect on the reliability of the resonance spring 38 composed of the coil spring 36 and the leaf spring 37 described above is as follows when Freon R410A having a high pressure difference or carbon dioxide as a natural refrigerant is used as the refrigerant. Resonance spring 38
Is more remarkable because of the increased load on the device.

Further, by disposing the coil spring 36 on the outer peripheral side of the piston 35, the coil spring 36 can be configured without requiring a special space for the coil spring 36. It can be realized by a configuration.

(Second Embodiment) FIG. 4 is a sectional view of a linear compressor according to a second embodiment. The linear compressor according to the present embodiment is the first embodiment described with reference to FIG.
Are substantially the same except for the mounting position of the linear compressor and the coil spring 61, and the same parts are denoted by the same reference numerals.

In the present embodiment, a seat surface 62 a facing the top dead center is provided at the center of the base plate 62 covering the bottom end side end surface of the outer yoke 42, and a bottom dead center is provided inside the piston 63. A seat surface 63a is provided, and a coil spring 61 is disposed therebetween. Also piston 63
The leaf springs 64a and 64b are disposed on the bottom dead center side end surface, and the piston 63 includes a coil spring 61 and a leaf spring 64.
a and 64b are elastically supported by a resonance spring 65. Other configurations are the same as those in FIG.

The effect of using the coil spring 61 and the leaf springs 64a and 64b together is the same as in the first embodiment. In the present embodiment, since the coil spring 61 is disposed inside the piston 63, the coil spring 61 can be configured without requiring a special space for the coil spring 61. It is possible to obtain the effect of

Further, since the configuration of the seating surface 63a of the coil spring 61 provided inside the piston 63 becomes easy, the same effect can be obtained at low cost.

Further, by disposing the coil spring 61 inside the piston 63, the piston 63 and the cylinder 66
The sealing surface 67 between them can be secured with a sufficient length, so that loss due to refrigerant leakage can be prevented and efficiency can be improved.

(Embodiment 3) FIG. 5 is a sectional view of a linear compressor according to Embodiment 3. The linear compressor according to the present embodiment is the first embodiment described with reference to FIG.
Are substantially the same except for the mounting position of the linear compressor and the coil spring 71, and the same parts are denoted by the same reference numerals.

In the present embodiment, a seating surface 72 a facing the top dead center side is provided at the bottom dead center side end surface of the piston 73 at the center of the base plate 72 covering the bottom end surface of the outer yoke 42. The leaf spring 74 has a seat surface 7 facing the bottom dead center side.
4a is installed, and a coil spring 71 is arranged between them. The piston 73 is elastically supported by a resonance spring 75 including a coil spring 71 and a leaf spring 74. Other configurations are the same as those in FIG.

The effect of using the coil spring 71 and the leaf spring 74 together is the same as in the first embodiment. In the present embodiment, since the coil spring 71 is disposed between the leaf spring 74 and the base plate 72, a special configuration is not required only by adding the coil spring 71 to the conventional configuration. Can achieve the same effect at low cost.

Further, since the coil spring 71 is disposed between the leaf spring 74 and the base plate 72,
Only the piston 73 will directly support it. Therefore, even when the axis of the coil spring 71 and the leaf spring 74, that is, the axis on which the elastic force of the coil spring 71 and the leaf spring 74 acts slightly shifts, the leaf spring 74 absorbs the moment due to the shift of these forces, It does not act on the piston 73. Therefore, this moment causes the piston 73 to move the cylinder 7
6, it is possible to prevent the sliding surface pressure between the piston 73 and the cylinder 76 from rising due to the inclination within the range of the gap between the piston 6 and the cylinder 6, thereby improving the reliability of the sliding surface between the piston 73 and the cylinder 76. In addition, the sliding loss can be reduced and the efficiency can be improved.

[0068]

As described above, according to the present invention, a coil spring and a leaf spring are used together, and the coil spring is formed inside the piston or on the outer peripheral side of the piston. Thus, a large amount of deflection and a high spring constant can be achieved at the same time, so that high reliability can be ensured even when used in a refrigeration cycle having a high differential pressure.

Further, by using the coil spring and the leaf spring together, the side force generated by the coil spring can be restrained by the leaf spring, and the sliding force between the piston and the cylinder elastically supported by the resonance spring can be reduced. The frictional force due to the generated side force can be minimized, and the efficiency and reliability can be improved.

A coil spring and a leaf spring are used together, and the coil spring is mounted so as to be compressed when the piston moves to the bottom dead center side, so that the coil spring and the leaf spring apply a preload to each other during assembly. By providing the coil spring with a sufficient amount of compression deflection from the time of assembly, the coil spring will always receive compression deflection within the movable range from the top dead center to the bottom dead center of the piston. Since it can be used, the reliability of the coil spring can be improved.

At the same time, the amount of deflection at the top dead center side is given to the leaf spring in advance, and the leaf spring falls within the allowable deflection amount even when the piston moves to the lower dead center side. Therefore, even when the same leaf spring is used, the allowable stroke of the piston can be increased, and the reliability of the leaf spring can be improved.

Further, even when the piston moves to the bottom dead center side and the coil spring is compressed to the close contact height, the leaf spring does not exceed the allowable deflection range, so that the leaf spring exceeds the allowable deflection amount. Since bending can be prevented, high reliability can be ensured even when used in a refrigeration cycle having a high differential pressure.

Further, if the coil spring is arranged on the bottom end side end face of the leaf spring, the above-described effect can be obtained by a simple configuration that does not require a special configuration by simply adding the coil spring to the conventional configuration. Can be. At the same time, even if the axis on which the elastic force of the coil spring and the leaf spring acts is slightly displaced, the leaf spring absorbs the moment due to the deviation of these forces, this moment does not act on the piston, and the piston and the cylinder slide. An increase in surface pressure can be prevented, the reliability of the sliding surface between the piston and the cylinder can be improved, the sliding loss can be reduced, and the efficiency can be improved.

The above effects are particularly effective when Freon R410A having a particularly high differential pressure or carbon dioxide as a natural refrigerant is used as the refrigerant.

[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 cross-sectional view of the linear compressor in a state where a piston is moved to a top dead center side;

FIG. 3 is a cross-sectional view of the linear compressor in a state where a piston has moved to a bottom dead center side;

FIG. 4 is a sectional view of a linear compressor according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a linear compressor according to Embodiment 3 of the present invention.

FIG. 6 is a sectional view of a conventional linear compressor.

[Explanation of symbols]

1,31 Closed container 2,32 Compression mechanism 4,34,66,76 Cylinder 5,35,63,73 Piston 6a, 6b, 6c, 37,64a, 64b, 74 Leaf spring 36,61,71 Coil spring 15 , 47 Compression chamber

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sadao Kawahara 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Terms (reference) 3H076 AA02 BB28 BB31 BB43 CC03 CC28 CC31 5H633 BB03 GG02 GG04 GG09 GG16 HH03 HH07 HH13 JA02 JB05

Claims (8)

[Claims] 1. A piston comprising: a cylinder; a piston engaged with the cylinder to form a compression chamber; and a linear motor for reciprocating the piston in an axial direction of the cylinder. , Which are supported so as to be able to reciprocate in the axial direction of the cylinder. 2. The linear compressor according to claim 1, wherein the coil spring is installed so as to be compressed when the piston moves to a bottom dead center side. 3. The linear compressor according to claim 1, wherein said leaf spring and said coil spring apply a preload to each other during assembly. 4. The leaf spring according to claim 1, wherein the amount of deflection of the leaf spring when the coil spring is compressed to the contact height falls within the allowable deflection of the leaf spring. Linear compressor. 5. The linear compressor according to claim 1, wherein the coil spring is arranged on an outer peripheral side of the piston. 6. The linear compressor according to claim 1, wherein said coil spring is disposed inside said piston. 7. The linear compressor according to claim 1, wherein the coil spring is arranged on a side of the leaf spring opposite to the piston. 8. The linear compressor according to claim 1, wherein the linear compressor is operated using a refrigerant containing carbon dioxide as a main component.