KR101487031B1 - Linear compressor - Google Patents

Abstract

A linear compressor according to the present invention includes: a cylinder having a compression space therein; A frame fixed to an axial one end peripheral surface of the cylinder; An inner stator sandwiched between the outer circumferential surface of the cylinder so as to abut the frame; An outer stator which is fitted so as to maintain a clearance on an outer circumferential surface of the inner stator so as to abut the frame, and which overlaps one end of the inner stator in the axial direction so as to press the frame; Since the motor cover is coupled in the axial direction of the outer stator and fastened to the frame and bolts to fix the stator to the frame, the inner stator can be fixed while fixing the outer stator, thereby simplifying the assembling process Thereby enhancing productivity.

Linear compressor, frame, cylinder, inner stator, outer stator, motor cover

Description

[0001] LINEAR COMPRESSOR [0002]

The present invention relates to a linear compressor capable of ensuring high efficiency in response to a demand for a low compression capacity and a small installation space, and more particularly to a linear compressor capable of fixing two stator units at the same time.

BACKGROUND ART [0002] Generally, a reciprocating compressor is constituted such that a compression space in which a working gas is sucked and discharged is formed between a piston and a cylinder, so that the piston linearly reciprocates within the cylinder and compresses the refrigerant.

In recent years, since the reciprocating compressor includes components such as a crankshaft in order to convert the rotational force of the driving motor to the reciprocating linear motion force of the piston, there is a problem that mechanical loss due to the motion conversion is largely generated. A large number of linear compressors are being developed.

In particular, the linear compressor is directly connected to a linear motor in which the piston reciprocates linearly, so that there is no mechanical loss due to the switching of the motion, so that the compression efficiency is improved and the structure is simple. Since the operation can be controlled, the noise is smaller than that of other compressors, and thus it is widely applied to home appliances such as refrigerators used indoors.

FIG. 1 is a cross-sectional view showing an example of a linear compressor according to the prior art, and FIG. 2 is an exploded side sectional view showing an example of a linear motor applied to a linear compressor according to the related art.

1, the conventional linear compressor includes a frame 2, a cylinder 3, a piston 4, a suction valve 5, a discharge valve assembly 6, a motor cover (not shown) 7, the supporter 8, the back cover 9, the muffler assembly 10, the eight springs 20, and the linear motor 30 are elastically supported. Of course, the closed container 1 is provided with a suction pipe 1a through which refrigerant is sucked and a discharge pipe 1b through which the compressed refrigerant is discharged.

The springs 20 are installed such that the piston 4 is elastically supported in the axial direction so that four first springs 21 are installed between the motor cover 7 and the supporter 8, (22) is provided between the supporter (8) and the back cover (9). Therefore, when the piston 4 moves in the direction of compressing the refrigerant, the first springs 21 compress and elastically support the piston 4. On the other hand, when the piston 4 moves in the direction of sucking the refrigerant, The second springs 22 are compressed and the piston 4 is elastically supported.

The linear motor 30 maintains an air gap between the inner stator 31 and the outer stator 32 as shown in Figs. 1 and 2, and the permanent magnet 33 is reciprocated And the piston 4 is reciprocally driven as the permanent magnet 33 is connected to the piston 4 by the connecting member 34. [ The inner stator 31 is formed in a cylindrical shape in which the lamination is laminated in the circumferential direction. The inner stator 31 is fitted to the outer circumferential surface of the cylinder 3 so that one axial end of the inner stator 31 abuts on one surface of the frame 2, The fixing ring C is fitted in the fixing groove 3h provided in the cylinder 3 and the fixing groove 31h provided in the end portion of the inner stator 31 so that the other end of the inner stator 31 in the axial direction is inserted into the cylinder 3) It is fixed to the outer circumferential surface. The outer stator 32 has a plurality of cores 32B coupled to the coil winding body 32A at regular intervals in the circumferential direction. The core 32B is installed to surround the outer circumferential surface of the coil winding body 32A, And a pair of pawls are provided to surround a part of the inner circumferential surface of the coil winding body 32A. Of course, the outer stator 32 is installed so as to maintain a clearance with the outer circumferential surface of the inner stator 31. The outer stator 32 is positioned so as to abut the frame 2 and the motor cover 7 in the axial direction, (7) is bolted to the frame (2). The permanent magnet 33 is provided so that the poles NS are located on the surface facing the inner stator 31 and the surface facing the outer stator 32 and the connecting member 34 And is connected to the piston (4). Therefore, the permanent magnet 33 reciprocates linearly by the mutual electromagnetic force between the inner stator 31, the outer stator 32 and the permanent magnet 33 to operate the piston 4.

Therefore, the moving member composed of the piston 4 and the permanent magnet 33 moves the mechanical spring 20 from both sides with respect to the linear motion direction with respect to the fixed member composed of the cylinder 3 and the stator 31, The MK resonance frequency defined by the mass M of the moving member and the spring constant K of the springs supporting the mass M is calculated and the power frequency applied to the linear motor 30 is set to By designing to follow the MK resonant frequency, the efficiency of the linear compressor can be optimized.

Hereinafter, the operation of the conventional art will be described.

When the power is input to the coil winding body 32A, the inner stator 31 and the outer stator 32 are ignited alternately with the N / S poles, and the permanent magnet 33 positioned therebetween is interposed between the inner stator 31 And reciprocatingly linearly moves while being moved by an attractive force or a repulsive force according to the pole change of the outer stator 32. At this time, if the center of the permanent magnet 33 deviates from the ends of the two poles of the outer stator 32, the permanent magnet 33 will not be attracted by the attraction force or the external divergence of the electromagnetic field will become large, 31 or the outer stator 32 or the electromagnetic field radiated to the outside of the hermetically sealed container 1 or other components in the hermetically sealed container 1, the operation reliability is lowered. To prevent this, the piston 4), that is, the moving distance of the permanent magnet 33, has been strictly limited to the two pole ends of the outer stator 32 by the center of the permanent magnet 33. For this purpose, a plurality of Mechanical springs have been used to elastically support the moving member as shown in Fig.

When the linear motor 30 is operated as described above, the piston 3 and the muffler assembly 10 connected thereto are linearly reciprocated, and as the pressure in the compression space P changes, the suction valve 5 and the discharge valve assembly The refrigerant flows through the suction holes 1a of the hermetically sealed container 1, the openings of the back cover 9, the muffler assembly 10 and the piston 3, P and is then discharged to the outside through the discharge valve assembly 6, the loop pipe (not shown) and the discharge pipe 1b of the closed container 1. [

Recent linear compressors are being developed not only to be easily applied to low capacity but also to be easily installed in a small space. However, in the conventional linear compressor and the linear motor applied thereto, the stroke length of the piston 4 is set to a distance that the center of the permanent magnet 33 is reciprocatingly linearly moved between the two poles of the outer stator 32 It is not suitable for use in a low-capacity simple structure because it uses a plurality of springs 20 for this purpose.

Therefore, according to the present invention, as one end of the inner stator and the outer stator are connected to each other, the structure of the linear motor in which the permanent magnet reciprocates linearly between only one pole of the inner stator and the outer stator is improved, and the permanent magnet and the piston The length of the cylinder into which the piston is inserted is also shortened. However, since the length of the cylinder is shorter than the length of the inner stator, the inner stator can not be fixed to the outer circumferential surface of the cylinder by the stationary ring, and a separate fixing structure is required.

An object of the present invention is to provide a linear compressor capable of increasing the efficiency by using a magnetic spring constant, by making the linear motor structure change, by integrating or eliminating the component parts to make it lighter or smaller.

Another object of the present invention is to provide a linear compressor capable of fixing two stator units at the same time.

According to an aspect of the present invention, there is provided a compressor comprising: a cylinder having a compression space therein; A frame fixed to an axial one end peripheral surface of the cylinder; An inner stator sandwiched between the outer circumferential surface of the cylinder so as to abut the frame; An outer stator which is fitted so as to maintain a clearance on an outer circumferential surface of the inner stator so as to abut the frame, and which overlaps one end of the inner stator in the axial direction so as to press the frame; And a motor cover coupled in the axial direction of the outer stator and bolt-fastened to the frame to provide a fixing force to fix the stator to the frame.

In the present invention, the inner stator is provided with a fixing protrusion protruding in the outer circumferential direction on one axial end peripheral surface, and the outer stator has a fixing groove for pressing the fixing protrusion of the inner stator in the axial direction on the one- .

Further, in the present invention, the frame is provided with a positioning groove in which a fixing projection of the inner stator is partially received.

Further, in the present invention, when the fastening protrusion of the inner stator and the fastening groove of the outer stator are engaged, one end in the axial direction of the inner stator comes into contact with the frame, and one end in the axial direction of the outer stator holds the gap with the frame do.

Further, in the present invention, the linear compressor further includes a piston for reciprocating linear motion within the cylinder and compressing the working gas, and a plurality of permanent magnets for linearly moving the piston reciprocally by the electromagnetic force in the clearance between the inner stator and the outer stator And the outer stator is provided with a pawl which forms a clearance with the inner stator in a direction opposite to a portion connected to the inner stator. When the permanent magnets linearly move reciprocatingly in the gap between the rotor stator and the outer stator, , The at least one permanent magnet deviates from the gap space portion between the inner stator and the pole of the outer stator.

Further, in the present invention, the linear compressor includes springs which elastically support the piston at both sides in the reciprocating linear motion direction, and are defined by the mass M of the movable member including the piston and the permanent magnets, A mechanical spring constant (K _mechanical ), a gas spring constant (K _gas ) defined by the working fluid pressure in the compression space, and a permanent magnet having one pole center of the permanent magnet at the time of reciprocating linear motion in the gap between the inner stator and the outer stator (F _o ) defined by a magnetic spring constant (K _magnet ) defined by the restoring force to match the center of the pole of the outer stator.

Further, in the present invention, the springs are the first and second springs which support the piston from both sides in the axial direction.

The first spring is installed between the cylinder and the flange of the piston, and the second spring is installed between the piston flange and the back cover. .

Further, in the present invention, the cylinder is formed to have a shorter axial length than the inner stator or the outer stator.

Further, in the present invention, the cylinder and the frame are integrally formed of a magnetic material.

The linear compressor according to the present invention configured as described above employs a linear motor in which two permanent magnets connected in the direction of motion between one pole of the inner stator and the pole of the outer stator reciprocate linearly. Since the mechanical spring constant (K _mechanical ) can be designed to be low by designing the resonance frequency in consideration of the magnetic spring constant (K _magnet ), only two springs can be configured to support the piston, Since the two springs allow the piston to be elastically supported directly, the supporter can be omitted or the shape of the motor cover can be simplified, which makes it possible to reduce the capacity, weight and size.

Further, since the inner stator is improved to a linear motor structure in which one end of the inner stator and the outer stator are connected to each other, even if the length of the cylinder becomes shorter than the length of the inner stator, if the outer stator is fixed to the frame by the motor cover, So that the assembly process can be simplified and the productivity can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a plan view showing an example of a linear compressor according to the present invention, and FIG. 4 is a side sectional view showing an example of a structure of a linear compressor according to the present invention.

3 and 4, the linear compressor according to the present invention includes a hermetically sealed container 101 having a suction pipe 101a and a discharge pipe 101b through which a refrigerant is sucked / discharged, The valve assembly 100 includes a frame 102, a cylinder 103, a piston 104, a suction valve 105 and a discharge valve assembly 106, a motor cover 107, a back cover 108, a suction muffler 110, 120: 121, 122) and the linear motor 130 are elastically supported.

The frame 102 and the cylinder 103 are integrally formed. However, the frame 102 and the cylinder 103 may be formed of a magnetic material due to the characteristics of the linear motor 130 according to the present invention. That is, in the conventional linear compressor, as described above, there are two pawls in the linear motor, and since the magnetic flux leaks through the gap existing in the pole on the cylinder side, the frame is magnetized and therefore one of the frame, cylinder, Should be made of a non-magnetic material such as aluminum. However, in the linear motor 130 according to the present invention, the inner stator 131 and the outer stator 132 of the linear motor 130 abut against each other on the side of the frame 102 and the cylinder 103 It is not necessary to form the frame 102 or the cylinder 103 as a nonmagnetic material and the frame 102 and the cylinder 103 are made of cast iron or the like because there is no fear that the magnetic flux leaks to the outside as a closed loop is formed therebetween. Can be integrally cast.

The cylinder 103 is formed in a cylindrical shape in which the compression space P can be provided. Since the stroke length of the piston is shorter than that of the conventional linear compressor, the cylinder 103 is formed shorter in the axial direction than the conventional cylinder. Is shorter than the axial length of the stator (131, 132) of the linear motor (130).

The piston 104 has a head 104a provided at a closed end of the cylinder and provided with a suction port 104h for sucking the refrigerant into the compression space P, And a portion 104b. In order to prevent leakage of the magnetic force from the linear motor 130, a part of the linear motor 130 may be made of a non-magnetic material. This is because a pole exists in the linear motor 130 according to the present invention toward the flange portion 104b of the piston 104 as will be described later. The magnetic flux leaking through the gap of the pole causes the magnetic member It is because it magnetizes. The head portion 104a of the piston 104 is installed to be inserted into the cylinder 103 and the flange portion 104b of the piston 104 is inserted into the magnet portion 133 of the linear motor 130, And is elastically supported in the axial direction by two springs 120 (121, 122).

Of course, the suction valve 105 is mounted on the head 104a of the piston 104, the discharge valve assembly 106 is mounted on one end of the compression space P of the cylinder 103, And is operated to open and close in accordance with the pressure change.

The motor cover 107 fixes the linear motor 103 to be described later to the frame 102 so that one end in the axial direction of the linear motor 130 is supported on the frame 102, The other end of the motor cover 107 is covered with the motor cover 107, and then the motor cover 107 is bolted to the frame 102. The outer stator 132 of the linear motor 130 is fixed between the actual frame 102 and the motor cover 107. When the inner stator 131 is fixed while the outer stator 132 of the linear motor 130 is fixed, Can be configured to be fixed together, an example of which will be described in detail below.

The back cover 108 is formed by bending the flat plate to accommodate the flange portion 104b of the piston 104 and the suction muffler 110 and has a motor cover 107, respectively. The cap 108a of the back cover 108 may be attached to the closed container 108. The cap 108a of the back cover 108 may protrude from the closed container 108a, It is preferable that the round or the corner portion is rounded so as to serve as a stopper. Of course, the cap 108a of the back cover 108 is provided with an opening 108h for allowing the refrigerant to flow into the suction muffler 110 and is positioned on the straight line with the suction pipe 101a of the closed container 101 desirable.

The suction muffler 110 is fixed to the flange portion 104b of the piston 104 and guides various kinds of noise spaces and noise pipes so that the refrigerant is sucked up to the head portion 104a of the piston 104, (105). Of course, the suction muffler 110 may be formed of a non-magnetic material in part or in whole in order to prevent magnetic leakage of the linear motor 130.

The springs 120 include a first spring 121 supported by the end of the cylinder 103 and the flange 104b of the piston 104 and a second spring 121 supported by the flange 104b of the piston 104 and the cap And a second spring 122 which is supported by the second spring 108b. The first spring 121 is compressed when the piston 104 is moved in the direction to compress the refrigerant while the second spring 122 is compressed when the piston 104 is moved in the direction in which the refrigerant is sucked, The 1,2 springs 121 and 122 behave opposite to each other. In the linear motor 130 described below, since the value of the magnetic spring constant (K _magnet ) can have a meaning, unlike the conventional linear motor, the K _mechanical value can be made relatively small, It is possible to reduce the spring constant, that is, to reduce the total number of springs or to reduce the spring constant of the individual springs, that is, to reduce the diameter D, the diameter d and the length l of the individual springs . Accordingly, only the two springs 120 (121, 122) can be applied. Furthermore, the supporter that has been provided for installing a large number of springs in a more effective space can be omitted, or the spring support portion provided in the motor cover can be eliminated, , It can be lightened.

5 is a side cross-sectional view illustrating an example of the linear motor coupling applied to the linear compressor according to the present invention.

3 to 5, one end of the inner stator 131 and one end of the outer stator 132 in the axial direction are connected to each other, and the other part of the linear motor is maintained in a gap And the magnet portion 133 is disposed between the inner stator 131 and the outer stator 132 so as to reciprocate linearly by electromagnetic force.

The inner stator 131 may be manufactured in a lamination manner in the circumferential direction as in the prior art. The inner stator 131 may include fixing projections 131a extending in the radial direction on the outer circumferential surface at one end in the axial direction so as to be connected to the outer stator 132, And a protrusion 131b having an axially extending outer circumferential surface at one end in the axial direction is provided to increase the electromagnetic force. Since the inner stator 131 is formed to be longer than the axial length of the cylinder 103, the inner stator is hardly fixed to the outer circumferential surface of the cylinder as in the conventional case. To compensate for this, the inner stator 131 is fixed to the outer stator 132 , But will be described in detail below.

The outer stator 132 is provided so as to surround a portion of the coil winding body 132A in which the coil is wound in the circumferential direction and a portion of the coil winding body 132A except for the inner circumferential surface at regular intervals in the circumferential direction of the coil winding body 132A The core 132B is configured such that only a part of the lamination in the circumferential direction is laminated such that the side end face of the core 132B is in the shape of "┗┛". At this time, the core 132B has two ends positioned to face the fixing protrusions 131a and the protrusion 131b of the inner stator 131, and one end of the core 132B is provided with the inner stator 131 The outer circumferential surface of the inner stator 131 and the protruding portion 131b of the inner stator 131 are provided with a fixing groove 132a which overlaps with the fixing protrusion 131a in the axial direction. (132b). Further, the fixing groove 132a of the core 132B is formed so as to overlap with the fixing protrusion 131a of the inner stator 131 or to be able to press the inner stator 131 by the fastening force acting in the axial direction And the pawl 132b of the core 132B is extended in both axial directions in order to increase the area of the surface facing the inner stator 131 in order to increase the electromagnetic force like the protrusion 131b of the inner stator 131. [ (132b ') is preferably formed.

Of course, the core applied to the conventional outer stator is provided with two pawls. In order to increase the electromagnetic force, the area of the pawls facing the inner stator is formed to extend in the axial direction. And two laminated laminated laminated layers having a side cross-sectional shape of '┗' and '┛', respectively. Then, the two core blocks were combined with a coil winding body by using a complex joining member and a joining method The core 132B applied to the outer stator 132 of the present invention is formed of one core block laminated with laminations having a side cross-sectional shape of '┛┛' because only one pole 132b is provided, (132A), so that the manufacturing process can be simplified.

The first and second permanent magnets are coupled to the inner stator 131 and the outer stator 132. The first and second permanent magnets 133 and 132 are connected to the first and second permanent magnets 131 and 132, And the pawls 132b of the first clutch C1. That is, since one end of the inner stator 131 and the outer stator 132 are connected to each other in the axial direction, an electromagnetic force is generated only between the inner stator 131 and the pole 132b of the outer stator 132, (Not shown) are connected to each other in the axial direction so that the magnet portion 133 reciprocates linearly even if the pole is changed only in one pole 132b of the magnet portion 133. However, It is preferable that the two permanent magnets are connected to each other at different poles.

The linear motor 130 is coupled between the frame 102 and the cylinder 103 and the motor cover 107. The frame 102 is provided with an inner stator 131 Is provided with a positioning groove 102h in which a part of the fixing protrusion 131a of the positioning groove 102h can be received. At this time, the thickness of the fixing protrusion 131a of the inner stator 131 is formed to be thicker than the depth of the positioning groove 102h of the frame 102, and the thickness of the fixing protrusion 131a of the inner stator 131 The thickness of the fixing protrusion 131a of the inner stator 131 is set to be larger than the depth of the positioning groove 102h of the frame 102 and the depth of the fixing groove 132a of the outer stator 132 Is formed to be larger than the sum of the sum of the thicknesses

The following is a description of a coupling process of the linear motor constructed as above.

When the inner stator 131 is fitted to the outer circumferential surface of the cylinder 103, the fixing projections 131a of the inner stator 131 are seated in the positioning grooves 102h of the frame 102, The fixing groove 132a of the outer stator 132 is engaged with the fixing protrusion 131a of the inner stator 131. [ One end in the axial direction of the outer stator 132 engaged with the inner stator 131 maintains a clearance with the frame 102 and the pole 132b of the outer stator 132 is spaced apart from the outer peripheral surface of the inner stator 131, Respectively.

Thereafter, the motor cover 107 is coupled to cover the outer circumferential surface of the one end of the outer stator 132 in the axial direction, and then the motor cover 107 is bolted to the frame 102. Of course, the bolt passes through the space between the cores 132B of the outer stator 132 to join the frame 102 and the motor cover 107, and the outer stator 132 And the fixing grooves 132a of the outer stator 132 press the fixing projections 131a of the inner stator 131 against the frame 102 by the fastening force acting on the outer stator 132, The inner stator 131 can be fixed with the outer stator 132 easily. When the fixing protrusion 131a of the inner stator 131 is seated in the positioning groove 102h of the frame 102 and at the same time is engaged with the fixing groove 132a of the outer stator 132, The outer stator 132 is brought into contact with the frame 102 as the motor cover 107 is fastened so that the outer stator 132 abuts the frame 102 while the outer stator 132 abuts the frame 102. [ The inner stator 131 is pressed with a predetermined force so that the fastening force is maintained at a higher level.

Since the portions where the inner stator 131 and the outer stator 132 are connected to each other form a closed loop in this manner, even if the diathermal inner stator 131 and the outer stator 132 come into contact with the frame 102, The frame 102 and the cylinder 103 do not need to be made of a nonmagnetic material such as aluminum by injection molding or the like and can be easily formed into a casting body by a cast iron .

6A and 6B are diagrams showing an example of operation of a linear motor applied to a linear compressor according to the present invention.

As shown in FIGS. 6A and 6B, as the power is input to the coil winding body 132A, the inner stator 131 and the pole 132b of the outer stator 132 alternate with the N-S poles. 6A, when the pole 132b of the outer stator 132 has the N pole, the S pole of the magnet portion 133 is pulled out and at the same time the N pole of the magnet portion 133 is pushed out, The magnet portion 133 moves in the uniaxial direction so that the first permanent magnet 133a is positioned between the inner stator 131 and the pawl 132b of the outer stator 132. The center of the first permanent magnet 133a, The second permanent magnet 133b moves to the extent that it does not deviate from the end of the outer protrusion 132b 'of the inner stator 132. Accordingly, as the outer protrusion 132b' of the outer stator 132 moves away from the inner stator 131, And the pawl 132b of the outer stator 132 is completely deviated from the gap space portion. 6B, if the pole 132b of the outer stator 133 has the S pole, since the N pole of the magnet portion 133 is pulled out and the S pole of the magnet portion 133 is pushed out, The magnet portion 133 moves in the opposite direction so that the second permanent magnet 133b is positioned between the inner stator 131 and the pole 132b of the outer stator 132. Similarly, The first permanent magnet 133a moves away from the inner protruding end 132b 'of the outer stator 132 to the extent that the inner stator 131b does not deviate from the inner protruding end 132b' And the pawl 132b of the outer stator 132 are completely deviated from the gap space portion. That is, the moving distance of the magnet portion 133, that is, the stroke of the piston 104 is set such that the center of the first permanent magnet 133a is located at the end of the outer protruding portion 132b 'of the outer stator 132, And the center of the inner protrusion 133b is located at the end of the inner protrusion 132b 'of the outer stator 132.

In the linear motor according to the present invention as described above, when the magnet portion 133 including the two permanent magnets 133a and 133b is reciprocatingly linearly moved, another restoring force is applied to the magnet portion 133 of the linear motor, Lt; / RTI > This is because the permanent magnet of one of the magnet portions 133 is passed between the protruding portion 131b of the inner stator and the pole 132b of the outer stator as in Figs. 6A and 6B, and one of the permanent magnets 133 of the magnet portion 133 The electromagnetic striking force acts to return to the center of the pole 132b of the outer stator 132 by the electromagnetic force as the pole 132b of the outer stator 132 having the different poles departs from the center of the pole 132b, And the restoring force of the springs 120 supporting the moving member composed of the magnet portion 133 and the magnet portion 133. This is called a magnet spring in the present invention, What is defined is called a magnet spring constant (K _magnet ). Of course, the magnetic spring constant (K _magnet ) is set such that the center of the pole 132b of the outer stator 132 having the center of the permanent magnet of one of the magnet portions 133 is different from the center of the pole 132b of the outer stator 132 Lt; / RTI >

Therefore, in the linear compressor employing the linear motor of the present invention, since the mechanical spring constant (K _tmechanical ) is designed to be small considering the magnetic spring constant (K _magnet ), the size of the springs can be reduced. More specifically, in order to operate the linear compressor most efficiently, the power frequency f is designed to be adjusted to the resonance frequency (f _o ). When the linear compressor of the present invention is designed according to the linear motor characteristic of the present invention, It is preferable that the resonance design is performed considering the magnetic spring constant (K _magnet ) as shown in the following equation.

That is, when the power supply frequency f supplied to the linear motor is determined, the mass M of the moving member made up of the piston and the permanent magnet, the number of the springs supporting the piston on both sides in order to adjust the power frequency f to the resonance point (K _mechanical ) defined as the restoring force, a spring constant (K _gas ) defined as the pressure acting on the gas sucked into the compression space, and a restoring force acting as the center of the permanent magnet moves away from the pole center of the stator The magnetic spring constant (K _magnet ) can be adjusted. At this time, the mass M of the moving member is determined for each product and the gas spring constant K _gas is also determined according to the type of the refrigerant. The gas spring constant K _gas is variable depending on the load, ) Of the movable member is maintained at a predetermined value or more, the mass M of the movable member and the gas spring constant (K _gas ) are regarded as fixed values since the influence of the gas spring acting on the movable member can be reduced. Thus, to match the power-supply frequency (f) in resonance, mechanical spring constant (K _mechanical) and magnetic spring constant, it is preferable to adjust the (K _magnet), the magnetic spring constant (K _magnet) compared to the conventional as described above, It is desirable that the _mechanical spring constant (K _mechanical ) is designed to be smaller than the conventional one. As a result, in the example of the linear compressor according to the present invention, the number n of the springs supporting the piston reciprocating linearly in the both axial directions, the diameter D, the diameter d, and the length l Can be designed to be small, and the parts for supporting the springs can be omitted, thereby making it lightweight and compact.

In the foregoing, the present invention has been described in detail by way of examples on the basis of the embodiments of the present invention and the accompanying drawings. However, the scope of the present invention is not limited by the above embodiments and drawings, and the scope of the present invention will be limited only by the content of the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan sectional view showing an example of a linear compressor according to the prior art; Fig.

Fig. 2 is an exploded side cross-sectional view showing an example of a linear motor applied to a linear compressor according to the prior art; Fig.

3 is a plan sectional view showing an example of a linear compressor according to the present invention.

4 is a side sectional view showing an example of a structure of a linear compressor according to the present invention.

5 is a side cross-sectional view illustrating an example of the linear motor coupling applied to the linear compressor according to the present invention.

6A to 6B illustrate an example of operation of a linear motor applied to a linear compressor according to the present invention.

Claims (10)

A cylinder having a compression space therein; A frame fixed to an axial one end peripheral surface of the cylinder; An inner stator sandwiched between the outer circumferential surface of the cylinder so as to abut the frame; An outer stator which is fitted so as to maintain a clearance on an outer circumferential surface of the inner stator so as to abut the frame, and which overlaps one end of the inner stator in the axial direction so as to press the frame; And, And a motor cover coupled in the axial direction of the outer stator and bolted to the frame to provide a clamping force to fix the stator to the frame. The method according to claim 1, The inner stator is provided with a fixing projection projecting in an outer circumferential direction on an outer peripheral surface at one end in the axial direction, Wherein the outer stator is provided with a fixing groove for pressing the fixing protrusion of the inner stator in the axial direction on the inner circumferential surface at one end in the axial direction. 3. The method of claim 2, Wherein the frame has a positioning groove in which a fixing projection of the inner stator is partially housed. 3. The method of claim 2, When the fixing projection of the inner stator and the fixing groove of the outer stator are engaged, One axial end of the inner stator is in contact with the frame, And one end in the axial direction of the outer stator maintains a clearance with the frame. 5. The method according to any one of claims 1 to 4, The linear compressor further includes a piston for reciprocating linear motion inside the cylinder and compressing the working gas, and a plurality of permanent magnets for linearly reciprocating the piston by the mutual electromagnetic force in the clearance between the inner stator and the outer stator, The outer stator has a pole which forms a clearance with the inner stator in a direction opposite to a portion connected to the inner stator, Characterized in that at the top dead center and the bottom dead point, at least one permanent magnet deviates from the gap space part between the inner stator and the pole of the outer stator, when the reciprocating linear motion is performed in the gap between the rotor stator and the outer stator, compressor. 6. The method of claim 5, The linear compressor includes springs for elastically supporting the piston at both sides in the reciprocating linear motion direction, The mass M of the movable member including the piston and the permanent magnets, the mechanical spring constant K _mechanical defined by the restoring force of the springs, the gas spring constant K _gas defined by the working fluid pressure in the compression space, (F) defined by a magnetic spring constant (K _magnet ) defined by a restoring force that one pole center of the permanent magnet coincides with the pole center of the outer stator during reciprocating linear motion in the gap between the inner stator and the outer stator _o ). < / RTI > The method according to claim 6, And the springs are first and second springs which support the piston in both axial directions. 8. The method of claim 7, And a back cover installed to maintain an axial gap with the piston, The first spring is installed between the cylinder and the flange of the piston, And the second spring is installed between the piston flange and the back cover. 9. The method of claim 8, Wherein the cylinder has a shorter axial length than the inner stator or the outer stator. 10. The method of claim 9, Characterized in that the cylinder and the frame are integrally made of a magnetic material.

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