KR20100112472A - Linear compressor - Google Patents

Abstract

PURPOSE: A linear compressor is provided to simplify the shape of a motor cover by directly and elastically supporting a piston using two springs. CONSTITUTION: A linear compressor comprises a cylinder(103), a frame(102), an inner stator(131), and an outer stator(132). A compression space is formed inside the cylinder. The frame is fixed to one end of the cylinder. The inner stator is coupled to the outer surface of the cylinder to be in contact with the frame. The outer stator is coupled to the outer surface of the inner stator to be in contact with the frame and fixes the inner stator to the frame.

Description

Linear Compressor {LINEAR COMPRESSOR}

The present invention relates to a linear compressor capable of ensuring high efficiency while meeting the demand of low compression capacity and small installation space, and more particularly, to a linear compressor capable of fixing two stators at once.

In general, the reciprocating compressor is configured to compress the refrigerant while the piston reciprocates linearly within the cylinder by forming a compression space in which the working gas is absorbed and discharged between the piston and the cylinder.

Recently, the reciprocating compressor includes a component such as a crank shaft in order to convert the rotational force of the drive motor to the reciprocating linear kinetic force of the piston, there is a problem that a large mechanical loss caused by the movement change occurs. Many linear compressors have been developed for this purpose.

Such a linear compressor, in particular, allows the piston to be directly connected to a linear motor in reciprocating linear motion, thereby eliminating mechanical loss due to motion switching, thereby improving compression efficiency, and having a simple structure, and controlling power input to the linear motor. Since the operation can be controlled, the noise is lower than that of other compressors, so it is widely applied to home appliances such as refrigerators used indoors.

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

The conventional linear compressor has a frame 2, a cylinder 3, a piston 4, an intake valve 5, a discharge valve assembly 6, a motor cover inside the sealed container 1 as shown in FIG. 7), the supporter 8, the back cover 9, the muffler assembly 10, eight springs 20, the structure consisting of the linear motor 30 is installed to be elastically supported. Of course, the sealed container 1 is provided with a suction tube 1a through which the refrigerant is sucked and a discharge tube 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, and four first springs 21 are installed between the motor cover 7 and the supporter 8, and four second springs. The field 22 is installed between the supporter 8 and the back cover 9. Therefore, when the piston 4 moves in the direction of compressing the refrigerant, when the first springs 21 are elastically supporting the piston 4 while being compressed, while the piston 4 moves in the direction of sucking the refrigerant, The second springs 22 are compressed to elastically support the piston 4.

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 reciprocates linearly therebetween. Is installed to be movable, the permanent magnet 33 is connected to the piston 4 by the connecting member 34 to reciprocate the piston (4). The inner stator 31 is formed in a cylindrical shape in which the laminations are laminated in the circumferential direction. The inner stator 31 is fitted to the outer circumferential surface of the cylinder 3 so that the axial end of the inner stator 31 abuts on one surface of the frame 2. While the fixing ring C is fitted into the fixing groove 3h provided in the cylinder 3 and the fixing groove 31h provided at the end of the inner stator 31, the other end in the axial direction of the inner stator 31 is connected to the cylinder ( 3) It is fixed to the outer circumferential surface. The outer stator 32 is coupled to the coil winding body 32A at a circumferential direction with a plurality of cores 32B coupled thereto. The core 32B is installed to surround the outer circumferential surface of the coil winding body 32A. A pair of poles is provided to surround a part of the inner circumferential surface of the coil winding 32A. Of course, the outer stator 32 is installed to maintain a gap with the outer circumferential surface of the inner stator 31, the outer stator 32 is positioned to abut the frame 2 and the motor cover 7 in the axial direction, and then the motor cover (7) is fixed as bolted to the frame (2). Permanent magnet 33 has an NS pole, it is installed so that each pole (NS) is located on the surface facing the inner stator 31 and the outer stator (32), by the connecting member 34 It is installed to connect with the piston (4). Therefore, the piston 4 is operated while the permanent magnet 33 reciprocates linearly by mutual electromagnetic force between the inner stator 31 and the outer stator 32 and the permanent magnet 33.

Accordingly, the movable member composed of the piston 4 and the permanent magnet 33 has a mechanical spring 20 at both sides with respect to the fixed member composed of the cylinder 3 and the stators 31 and 32 with respect to the linear movement direction. Since the MK resonant frequency defined by the mass (M) of the moving member and the spring constant (K) of the springs supporting it is calculated, and the power source frequency applied to the linear motor 30 is calculated. By designing to follow the MK resonant frequency, the efficiency of the linear compressor can be optimized.

Looking at the operation of the prior art configured as described above are as follows.

When power is supplied to the coil winding 32A, the inner stator 31 and the outer stator 32 are ignited by alternating N / S poles, and the permanent magnet 33 positioned therebetween is connected to the inner stator 31. According to the pole change of the outer stator 32, the reciprocating linear motion is moved by the attraction force or the repulsive force. At this time, if the center of the permanent magnet 33 is out of the two pole ends of the outer stator 32, the permanent magnet 33 is the inner stator ((2) because the force does not reach the permanent magnet 33 or the external divergence of the electromagnetic field increases) 31, the operation reliability is lowered while magnetizing the airtight container 1 or other components in the airtight container 1 by the electromagnetic field dissociated between the outer stator 32 and the outer stator 32. The stroke of 4), i.e., the moving distance of the permanent magnet 33, has been strictly limited to the center of the permanent magnet 33 to the two pole ends of the outer stator 32. 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 reciprocated linearly, and the suction valve 5 and the discharge valve assembly are changed as the pressure of the compression space P is varied. (6) is operated, the refrigerant passes through the suction pipe (1a) of the sealed container (1), the opening of the back cover (9), the muffler assembly (10), the inlet of the piston (3) and the compressed space ( After being sucked into P) and compressed, it exits through the discharge valve assembly 6, the loop pipe (not shown), and the discharge pipe 1b of the sealed container 1 to the outside.

However, in the conventional linear compressor, the inner stator and the outer stator maintain a gap with each other, but the inner stator and the outer stator are fixed by the fixing ring and the motor cover separately in the axial direction so that the two stators are moved or operated as they are separately fixed. Relative rotation may occur between the stators during the operation, and there is a problem of reducing the efficiency of the motor.

Recently, linear compressors have been developed to be easily installed in a small space as well as being easily applied to low capacity. By the way, in the conventional linear compressor and the linear motor applied thereto, the distance of the center of the permanent magnet 33 is reciprocated linearly between two poles of the outer stator 32 because of the above-mentioned reason of the stroke length of the piston 4. Strictly restrictive and because of the use of several springs 20 for this purpose it is not suitable for use in simple structures of low capacity.

An object of the present invention is to provide a linear compressor that can be lightened or downsized by integrating or eliminating components by changing the linear motor structure, and improving efficiency by using a magnetic spring constant.

It is also an object of the present invention to provide a linear compressor which can be fixed so that relative rotation does not occur between two stators.

The present invention for solving the above problems is a cylinder provided with a compression space therein; A frame fixed to the axial one end outer circumferential surface of the cylinder; An inner stator fitted to the outer circumferential surface of the cylinder to be in contact with the frame; And an outer stator inserted into the outer circumferential surface of the inner stator to be in contact with the frame, the outer stator being connected to an axial end of the inner stator in contact with the frame to fix the inner stator to the frame. To provide.

In the present invention, the outer peripheral portion of the inner stator and the inner peripheral portion of the outer stator are welded.

In the present invention, the inner and outer stators are characterized in that one end in the axial direction forms the same surface.

In addition, in the present invention, the inner stator is provided with a projection projecting in the outer circumferential direction on one outer peripheral surface in the axial direction, the outer stator is provided with a fixing groove for pressing the projection of the inner stator in the axial direction on one inner circumferential surface of the axial direction. It is done.

In addition, in the present invention, the frame is characterized in that the positioning groove is provided with a portion of the projection of the inner stator.

In addition, in the present invention, when the projection of the inner stator and the fixing groove of the outer stator is coupled, the axial end of the inner stator is in contact with the frame, characterized in that the axial end of the outer stator maintains a gap with the frame.

In addition, in the present invention, the motor cover is bolted to the frame at the other end in the axial direction of the outer stator, and the motor cover for fixing the outer stator to the frame to abut the axial end of the outer stator by the coupling force to the frame; It is done.

In addition, in the present invention, the linear compressor further comprises a piston for compressing the working gas while reciprocating linear movement inside the cylinder, and a plurality of permanent magnets for reciprocating linear movement of the piston by mutual electromagnetic force in the gap between the inner and outer stators. The outer stator has a pole which is spaced apart from the inner stator in a direction opposite to the portion connected to the inner stator, and the permanent magnets have a top dead center and a bottom dead center when they reciprocate linearly in the gap between the outer stator and the outer stator. In, at least one permanent magnet is characterized by being out of the gap space between the pole of the inner and outer stator.

Also, in the present invention, the linear compressor includes springs that elastically support the piston in both reciprocating linear motion directions, and includes the mass M of the movable member including the piston and the permanent magnets, and the restoring force of the springs. The mechanical spring constant (K _mechanical ), the gas spring constant (K _gas ) defined by the working fluid pressure in the compression space, and when the permanent magnets reciprocate linearly in the gap between the inner and outer stators, It is characterized in that it is operated using the resonance frequency (f _o ) defined by the magnetic spring constant (K _magnet ) defined by the restoring force to match the pole center of the outer stator.

Further, in the present invention, the springs are characterized in that the first and second springs support the piston in both axial directions.

In addition, in the present invention, further comprises a back cover installed to space the piston in the axial direction, wherein the first spring is installed between the piston flange and the back cover, the second spring between the cylinder and the flange of the piston It is characterized by being installed.

In the present invention, the cylinder is characterized in that the axial length is shorter than the inner or outer stator.

In addition, in the present invention, the cylinder and the frame is characterized in that it is made of a magnetic material integrally.

The linear compressor according to the present invention configured as described above employs a linear motor in which two permanent magnets reciprocally linearly move in the direction of motion between one pole of the inner and outer stators, and a linear compressor employing such a linear motor. Since the mechanical spring constant (K _mechanical ) can be designed low by designing the same 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 directly support the piston, the supporter may be omitted or the motor cover shape may be simplified, thereby reducing the capacity, weight, and size.

In addition, the present invention is improved by a linear motor structure in which one end of the inner stator and the outer stator are connected to each other, thereby preventing relative rotation between the stators during movement or operation, and maintaining a constant electromagnetic force generated between the stators. This not only increases the efficiency of the motor, but also increases operating reliability. Furthermore, since the stators are fixed to the frame by the motor cover at once, the assembly process is simplified and the productivity is improved.

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

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

3 and 4, the linear compressor according to the present invention includes a sealed container 101 having a suction pipe 101a and a discharge pipe 101b through which refrigerant is sucked and discharged, and inside the sealed container 101. Frame 102, cylinder 103, piston 104, intake valve 105 and discharge valve assembly 106, motor cover 107, back cover 108, suction muffler 110, two springs ( 120: 121, 122, the structure consisting of the linear motor 130 is installed to elastically support.

The frame 102 and the cylinder 103 are integrally manufactured, but 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, two poles existed in the linear motor, and one of the frames, cylinders, and pistons is inevitably made because the frame magnetizes as the magnetic flux leaks through the gap existing in the poles on the cylinder side. The above had to be made of nonmagnetic material such as aluminum. However, in the linear motor 130 according to the present invention, as described later, the inner stator 131 and the outer stator 132 of the linear motor 130 are in contact with each other on the side of the frame 102 and the cylinder 103. Since there is no fear of magnetic flux leakage to the outside as the closed loop is formed between them, the frame 102 and the cylinder 103 need not be formed of nonmagnetic material, and the frame 102 and the cylinder 103 are made of cast iron or the like. It is possible to cast integrally.

Cylinder 103 is formed in a cylindrical shape that can be provided with a compression space (P), because the stroke length of the piston is shorter than the conventional linear compressor is formed in the axial direction shorter than the conventional cylinder, described below It is formed shorter than the axial length of the stators 131 and 132 of the linear motor 130 to be.

The piston 104 is provided at a closed end of the cylinder and has a head portion 104a having a suction port 104h for sucking refrigerant into the compression space P, and a plan formed to extend radially at the other open end of the cylinder. It is made of a branch 104b, in order to prevent magnetic leakage from the linear motor 130, a part may be made of a nonmagnetic material. This is because, as will be described later, the pole is also present in the linear motor 130 according to the present invention toward the flange portion 104b of the piston 104, and the magnetic flux leaked through the gap between the poles causes the magnetic member in the vicinity thereof. Because it magnetizes. At this time, the head portion 104a of the piston 104 is installed to be inserted into the cylinder 103, the flange portion 104b of the piston 104 is the magnet portion 133 of the linear motor 130 to be described below. At the same time it is connected to and is installed to elastically support in the axial direction by two springs (120: 121, 122).

Of course, the inlet valve 105 is mounted to the head portion 104a of the piston 104, and the discharge valve assembly 106 is mounted to one end of the compression space P of the cylinder 103, It is operated to open and close according to the pressure change.

The motor cover 107 fixes the linear motor 103 to the frame 102 to be described below, so that one end in the axial direction of the linear motor 130 is supported by the frame 102, and the shaft of the linear motor 130 is fixed. The other end of the direction is covered with the motor cover 107, and then the motor cover 107 is bolted to the frame 102. At this time, the outer stator 132 of the linear motor 130 is fixed between the actual frame 102 and the motor cover 107. The inner stator 131 is also fixed while the outer stator 132 of the linear motor 130 is fixed. It 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 a flat plate to accommodate the flange portion 104b of the piston 104 and the suction muffler 110, and the motor cover (ie, the front end thereof is located in a direction opposite to the linear motor 130). 107) is bolted. The back cover 108 has an additional cap 108a protruding from the rear so that the spring 122 is seated. Although the structure may vibrate, an additional stopper may be provided, but the cap 108a of the back cover 108 may be a sealed container ( It is preferable that a circular or corner portion is rounded so that it can act as a stopper while colliding with 101). Of course, the opening 108h is provided in the cap 108a of the back cover 108 to allow the refrigerant to flow into the suction muffler 110 and is located in line with the suction pipe 101a of the sealed container 101. desirable.

The suction muffler 110 is fixed to the flange portion 104b of the piston 104, and provided with various noise spaces and noise tubes to guide the refrigerant to be sucked up to the head portion 104a of the piston 104 and at the same time the suction valve. The opening and closing noise of the 105 is attenuated. Of course, some or all of the suction muffler 110 may be formed of a nonmagnetic material to prevent magnetic leakage of the linear motor 130.

The springs 120 have a first spring 121 supported at the end of the cylinder 103 and the flange 104b of the piston 104, the cap 104 of the piston 104 and the cap of the back cover 108. And a second spring 122 supported by 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 to suck the refrigerant, The first and second springs 121 and 122 behave in opposite directions. In the linear motor 130 to be described below, unlike the conventional linear motor, since the magnetic spring constant (K _magnet ) value can have a meaning, the mechanical spring constant (K _mechanical ) value can be relatively small, so that It is possible to design to reduce the spring constant, i.e. reduce the total number of springs, or reduce the spring constant of the individual springs, i.e. reduce the diameter (D), wire diameter (d) and length (l) of the individual springs. . Accordingly, only two springs 120 (121, 122) can be applied, and furthermore, the supporter, which is conventionally provided for installing more springs in a more effective space, can be omitted, or the spring support provided in the motor cover can be eliminated, thereby miniaturizing the compressor. Can be lightened.

5 and 6 are side cross-sectional views illustrating various coupling examples of the linear motor applied to the linear compressor according to the present invention.

In the first embodiment of the linear motor applied to the linear compressor according to the present invention, as shown in FIG. 5, one end of the inner stator 131 and the outer stator 132 in the axial direction are welded to each other, and the other portions thereof have a gap. The magnet unit 133 is installed between the inner stator 131 and the gap between the outer stator 132 so as to reciprocate linearly by mutual electromagnetic force.

The inner stator 131 may be manufactured in a form in which laminations are laminated in the circumferential direction as in the prior art, and the connection part 131a extended in the radial direction is provided on the outer circumferential surface of one end in the axial direction so as to be connected to the outer stator 132. In order to increase the electromagnetic force, a protrusion 131b having an outer circumferential surface of one end in the axial direction extending in the axial direction is provided. At this time, since the inner stator 131 is formed longer than the axial length of the cylinder 103 (shown in FIG. 4), the inner stator is hardly fixed to the outer circumferential surface of the cylinder as in the past, and the outer stator 131 is outer to compensate for this. Although fixed by the stator 132, it will be described in detail below.

The outer stator 132 is installed to surround the coil winding body 132A, in which the coil is wound in the circumferential direction, and a portion excluding the inner circumferential surface of the coil winding body 132A at regular intervals in the circumferential direction of the coil winding body 132A. Consisting of a plurality of cores (132B), the core (132B) is configured such that only a portion of the lamination having a lateral 'cross section' is laminated in the circumferential direction. At this time, the core 132B is provided with two ends positioned to face the fixing protrusion 131a and the protrusion 131b of the inner stator 131, and one end of the inner stator 131 is provided at one end of the core 132B. A fixing protrusion 132a welded to the fixing protrusion 131a is provided, and the other end of the core 132B has a pawl 132b which forms a gap with the outer circumferential surface of the inner stator 131 and the protrusion 131b. Is provided. Furthermore, since the fixing protrusion 132a of the core 132B is welded to the fixing protrusion 131a of the inner stator 131, one end of the inner stator 131 and the outer stator 132 are connected to each other to form a closed loop. This eliminates the possibility of magnetic flux leakage at the connecting portions of the stators 131 and 132. Like the protrusion 131b of the inner stator 131, the pole 132b of the core 132B extends in both axial directions in order to widen the area of the surface facing the inner stator 131 to increase the electromagnetic force. Is preferably formed.

Of course, the core applied to the existing outer stator is provided with two poles, so as to increase the area of the poles facing the inner stator in order to increase the electromagnetic force in the axial direction, the core having such a shape of the coil winding body In order to assemble the laminate into two core blocks in which the laminations having the shape of '┗' and '각각' are laminated, respectively, then the two core blocks are used to connect to the coil winding body by using a complicated coupling member and a coupling method. Since the core 132B applied to the outer stator 132 of the present invention is provided with only one pole 132b, the coil winding body is composed of one core block in which laminations having a side cross-sectional shape of '┗┛' are stacked. And 132A to simplify the fabrication process.

The magnet unit 133 is configured such that the first and second permanent magnets (not shown) having NS poles are coupled to contact with different poles, and the first and second permanent magnets are the inner stator 131 and the outer stator 132. It is preferably located so as to be axially arranged between the poles 132b. That is, since one end of the inner stator 131 and the outer stator 132 are connected to each other in the axial direction, electromagnetic force is formed only between the pole 132b of the inner stator 131 and the outer stator 132, and the outer stator 132 In order for the magnet part 133 to reciprocate linear movement even if the pole is changed only in one pole 132b of), the magnet part 133 itself is configured such that two permanent magnets (not shown) are connected to each other in the axial direction. It is preferable that two permanent magnets are connected to different poles.

The linear motor 130 as described above is coupled between the frame 102, the cylinder 103, and the motor cover 107. When the inner stator 131 and the outer stator 132 are connected by welding, stators ( As the connecting portions of the 131 and 132 are connected to form the same plane, it is preferable that the frame 102 abutting the same is formed flat.

Therefore, when looking at the coupling process of the first embodiment of the linear motor 130, the welding so that the fixing projections (131a) of the inner stator 131 and the fixing projections (132a) of the outer stator 132 to form the same plane. After being connected, the stators 131 and 132 are fitted to the outer circumferential surface of the cylinder 103, and the connecting portion W of the stators 131 and 132 is brought into contact with the frame 102. At this time, as the connecting portion W of the stators 131 and 132 is connected to form the same plane as the axial one ends of the stators 131 and 132, the flat surface of the frame 102 is connected to the connecting portions W of the stators 131 and 132. ) And axial end to abut one end in the axial direction.

Thereafter, the motor cover 107 is coupled to cover the outer circumferential surface of the other end in the axial direction of the outer stator 132, and then the motor cover 107 is bolted to the frame 102. Of course, the bolt penetrates the space between the cores 132B of the outer stator 132 to couple the frame 102 and the motor cover 107, but between the frame 102 and the motor cover 107, the outer stator ( The inner stator 131 may be fixed together with the outer stator 132 as the inner stator 131 is welded to the outer stator 132.

On the other hand, the second embodiment of the linear motor applied to the linear compressor according to the present invention is configured in the same manner as the first embodiment, as shown in Figure 6 the shaft of the inner stator 131 and the outer stator 132 One end of the direction is connected to each other and the other part is installed to maintain the gap, and the magnet part 133 is positioned between the gap between the inner stator 131 and the outer stator 132 to reciprocate linear motion by mutual electromagnetic force. It is installed so that it can be done. Of course, since the inner stator 131, the outer stator 132, and the magnet part 133 are configured in the same manner as in the first embodiment, detailed description thereof will be omitted.

However, the inner stator 131 and the outer stator 132 are provided with fixing projections 131a of the inner stator 131 and fixing projections 132a of the outer stator 132 which are in contact with each other in the axial direction so as to be fitted together. The fixing protrusion 132a of the outer stator 132 is provided with a fixing groove 132h that is fitted with the fixing protrusion 131a of the inner stator 131, and the inner stator 131 and the outer stator 132 are provided. Positioning groove (102h) is provided in the frame 102 so that the connecting portion of the). At this time, since the fixing protrusion 131a of the inner stator 131 is formed to be larger than the depth of the fixing groove 132h of the outer stator 132, the connection portion is formed even when the inner stator 131 and the outer stator 132 are joined together. A step t1 occurs in the axial direction. In addition, since the axial step t1 of the stators 131 and 132 is formed larger than the depth t2 of the positioning groove 102h of the frame 102, the fixing projection 131a of the inner stator 131 is formed. When assembled between the positioning groove 102h of the frame 102 and the fixing groove 132h of the outer stator 132, the axial end of the inner stator 131 is installed to abut the frame 102. The axial end of the outer stator 132 is installed to maintain the gap 102 and the gap t1-t2, and the gap is a fastening force for the outer stator 132 to be fastened to the inner stator 131. Keep it higher.

Therefore, when looking at the coupling process of the second embodiment of the linear motor 130, when the inner stator 131 is fitted to the outer peripheral surface of the cylinder 103, the fixing projection 131a of the inner stator 131 is frame 102 ), When the outer stator 132 is fitted to the outer circumferential surface of the inner stator 131, the fixing groove 132 a of the outer stator 132 is fixed to the inner stator 131. It is engaged with the dragon projection 131a. In this case, one end of the outer stator 132 in the axial direction maintains a gap with the frame 102, and the pole 132 b of the outer stator 132 is coupled to maintain a gap with the outer circumferential surface of the inner stator 131.

Thereafter, the motor cover 107 is coupled to cover the outer circumferential surface of the axial end of the outer stator 132, and then the motor cover 107 is bolted to the frame 102. Of course, the bolt penetrates the space between the cores 132B of the outer stator 132 to couple the frame 102 and the motor cover 107, but between the frame 102 and the motor cover 107, the outer stator ( The fixing groove 132a of the outer stator 132 presses the fixing projection 131a of the inner stator 131 to the frame 102 by the fastening force acting on the outer stator 132. The inner stator 131 can be easily fixed like the outer stator 132. Therefore, when the fixing projection 131a of the inner stator 131 is seated in the positioning groove 102h of the frame 102 and coupled with the fixing groove 132a of the outer stator 132, the inner stator ( 131 is in contact with the frame 102, while the outer stator 132 is to maintain the gap (t1-t2) with the frame 102, the outer stator 132 is frame (A) as the motor cover 107 is fastened While pressing the inner stator 131 with a predetermined force while in contact with the 102 to maintain a fastening force higher.

In this way, since the portion where the inner stator 131 and the outer stator 132 are connected to each other forms a closed loop, even if the inner stator 131 and the outer stator 132 contact the frame 102, the magnetic force is applied to the frame 102. Frame 102 and the cylinder 103 do not need to be made of a nonmagnetic material such as aluminum by injection molding, etc., and as a magnetic material, it is easily formed integrally with a cast iron. Can be.

7a to 7b is a view showing an example of the operation of the linear motor applied to the linear compressor according to the present invention.

As shown in FIGS. 7A to 7B, as the power is input to the coil winding 132A, the poles 132b of the inner stator 131 and the outer stator 132 float while alternately N-S poles. Therefore, as shown in FIG. 7A, when the pole 132b of the outer stator 132 has the N pole, the pole S of the magnet 133 is attracted and the N pole of the magnet 133 is pushed. The magnet part 133 is moved in the direction of one axis so that the first permanent magnet 133a is located between the inner stator 131 and the pole 132b of the outer stator 132, and the center of the first permanent magnet 133a is the outer stator. Inner stator 131 moves to a range not exceeding the end of the outer protrusion 132b 'of 132, so that the second permanent magnet 133b is out of the outer protrusion end 132b' of the outer stator 132. And the gap space between the pole 132b of the outer stator 132 is completely out of the gap. On the contrary, as shown in FIG. 7B, when the pole 132b of the outer stator 133 has an S pole, the pole pole 132b pulls the N pole of the magnet portion 133 and pushes the S pole of the magnet portion 133. The magnet part 133 moves in the opposite direction so that the two permanent magnets 133b are located between the inner stator 131 and the pole 132b of the outer stator 132. Similarly, the center of the second permanent magnet 133b is the outer. The inner permanent portion 132b 'of the stator 132 moves to a range that does not deviate from the end, and thus the first permanent magnet 133a leaves the inner protrusion 132b' of the outer stator 132 as the inner stator 131 moves. ) And the gap space between the pawl 132b of the outer stator 132 is completely out. That is, the moving distance of the magnet part 133, that is, the stroke of the piston 104 is the second permanent magnet from the point where the center of the first permanent magnet 133a is located at the end of the outer protrusion 132b 'of the outer stator 132 It can be seen that the center of the 133b is the moving distance between the points located at the end of the inner protrusion 132b 'of the outer stator 132.

However, in the linear motor according to the present invention as described above, while the magnet part 133 having the two permanent magnets 133a and 133b as described above reciprocates linearly, another restoring force is applied to the magnet part 133 of the linear motor. It will work. As shown in FIGS. 7A and 7B, the permanent magnet of one of the magnet parts 133 passes between the protrusion 131b of the inner stator and the pole 132b of the outer stator, and the permanent magnet of one of the magnet parts 133. As the poles 132b of the outer stator 132 with different poles move away from the center, an electromagnetic restoring force acts to return back to the center of the poles 132b of the outer stator 132 by an electromagnetic force, which is a piston. Since it acts as a mechanism such as the restoring force of the springs 120 for supporting the moving member consisting of the 104 and the magnet 133 is called a magnetic spring (magnet spring) in the present invention, by the restoring force by the magnetic spring What is defined is called the magnet spring constant (K _magnet ). Of course, the magnetic spring constant K _magnet is the end of the pole 132b of the outer stator 132 from the center of the pole 132b of the outer stator 132 having a different pole from the center of one permanent magnet of the magnet portion 133. It works only within the range of movement.

Therefore, the linear compressor employing the linear motor of the present invention has an effect of reducing the size of the springs because the mechanical spring constant K _tmechanical is designed to be small according to the magnetic spring constant K _magnet . In more detail, the linear compressor is designed to adjust the power source frequency f to the resonance frequency f _o for the most efficient operation. When the linear compressor of the present invention is designed according to the characteristics of the linear motor of the present invention, It is preferable that the resonance design is made in consideration of the magnetic spring constant K _magnet as shown in the equation.

That is, when the power source frequency f supplied to the linear motor is determined, the mass M of the moving member made of the piston and the permanent magnet and the springs supporting the piston in both the axial directions to adjust the power source frequency f to the resonance point. Mechanical spring constant (K _mechanical ) defined as restoring force, spring constant (K _gas ) defined as the pressure acting on the gas drawn into the compression space, and restoring force acting as the center of the permanent magnet leaves the stator pole center. The magnetic spring constant K _magnet may be adjusted. At this time, the mass (M) of the moving member is determined for each product, the gas spring constant (K _gas ) is also determined according to the type of refrigerant, the gas spring constant (K _gas ) is easy to change depending on the load, but the mass (M) of the moving member ), The mass M of the movable member and the gas spring constant K _gas are regarded as fixed values because the influence of the gas spring acting on the movable member can be reduced. Therefore, in order to adjust the power source frequency f to the resonance point, it is preferable to adjust the _mechanical spring constant K _mechanical and the magnetic spring constant K _magnet , and as described above, the magnetic spring constant K _magnet as compared to the conventional one. In consideration of this, it is preferable that the _mechanical spring constant (K _mechanical ) be smaller than the conventional design. As a result, in the example of the linear compressor according to the present invention, as described above, the number (n), diameter (D), diameter (d), and length (n) of the springs supporting the piston for reciprocating linear movement of the piston in both axial directions ( l) can be designed small, and the parts supporting the springs can be omitted, making it lighter and smaller.

In the above, the present invention has been described in detail by way of examples based on 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 contents described in the claims below.

1 is a plan sectional view showing an example of a linear compressor according to the prior art.

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

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

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

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

Figure 6 is a side cross-sectional view showing another coupling example of the linear motor applied to the linear compressor according to the present invention.

7a to 7b is a view showing an example of the operation of the linear motor applied to the linear compressor according to the present invention.

Claims (13)

A cylinder having a compression space therein; A frame fixed to the axial one end outer circumferential surface of the cylinder; An inner stator fitted to the outer circumferential surface of the cylinder to be in contact with the frame; And, And an outer stator inserted into the outer circumferential surface of the inner stator to be in contact with the frame, the outer stator being connected to an axial end of the inner stator in contact with the frame to fix the inner stator to the frame. The method of claim 1, A linear compressor, wherein the outer circumferential portion of the inner stator and the inner circumferential portion of the outer stator are welded. The method of claim 2, An inner stator and an outer stator are linear compressors, wherein one end in the axial direction forms the same surface. The method of claim 1, The inner stator is provided with protrusions protruding in the circumferential direction on one outer circumferential surface in the axial direction, The outer stator is a linear compressor, characterized in that the fixing groove for pressing the projection of the inner stator in the axial direction at one end in the axial direction. The method of claim 4, wherein The frame is a linear compressor, characterized in that provided with a positioning groove for receiving a portion of the projection of the inner stator. The method of claim 4, wherein When the projection of the inner stator and the fixing groove of the outer stator are combined, The axial end of the inner stator contacts the frame, An axial end of the outer stator maintains a gap with the frame. The method of claim 6, And a motor cover which is bolted to the frame at the other end of the outer stator in the axial direction, and fixes the outer stator to the frame such that the outer end of the outer stator is in contact with the frame by the coupling force. The method according to any one of claims 1 to 7, The linear compressor further includes a piston for compressing the working gas while reciprocating linear motion inside the cylinder, and a plurality of permanent magnets for reciprocating linear motion of the piston by mutual electromagnetic force in the gap between the inner and outer stators. The outer stator has a pole which is spaced apart from the inner stator in a direction opposite to the portion connected to the inner stator. Permanent magnets are linear, characterized in that when the reciprocating linear motion in the gap between the iterator and the outer stator, at the top and bottom dead center, at least one permanent magnet is out of the gap space between the pole of the inner and outer stator compressor. The method of claim 8, The linear compressor includes springs that elastically support the piston in both reciprocating linear motion directions; Mass (M) of movable member including piston and permanent magnets, mechanical spring constant (K _mechanical ) defined by the restoring force of the springs, gas spring constant (K _gas ) defined by the working fluid pressure in the compression space, permanent magnet Resonance frequency (f) defined by the magnetic spring constant (K _magnet ) defined by the restoring force that the pole center of the permanent magnet is to match the pole center of the outer stator during reciprocating linear motion in the gap between the inner and outer stator _o ) is operated using a linear compressor. 10. The method of claim 9, And the springs are first and second springs supporting the piston in both axial directions. The method of claim 10, And a back cover installed to space the piston in an axial direction. The first spring is installed between the piston flange and the back cover, And the second spring is installed between the cylinder and the flange of the piston. The method of claim 11, The cylinder is a linear compressor, characterized in that the axial length is formed shorter than the inner or outer stator. The method of claim 12, The cylinder and the frame is a linear compressor, characterized in that made of a magnetic material integrally.

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