KR20100112476A - Linear compressor - Google Patents

Abstract

PURPOSE: A linear compressor is provided to remove the need for a supporter or to simplify the shape of a motor cover by elastically supporting a piston directly by two springs. CONSTITUTION: A linear compressor comprises an airtight container(101), a cylinder(103), a frame(102), a piston(104), a linear motor(130), a motor cover(107), two or more mechanical springs(121,122), a plurality of shock-absorbing springs, and a backcover(108). The cylinder is held in the airtight container and comprises a compression space. One end of the cylinder fixed to the frame. One end of the piston is inserted into the cylinder. The linear motor makes the piston reciprocate. The motor cover fixes the linear motor to frame in an axial direction. The mechanical springs support the piston on both sides of the axial direction. The shock-absorbing spring elastically supports a structure in which parts except for the airtight container are assembled, in the airtight container. The backcover is connected to the motor cover and comprises a stopper. One mechanical spring is settled on the stopper and the stopper is projected toward the airtight container in order to bump against the airtight container by vibration.

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 a small installation space, and in particular, even if a structure installed buffered inside the sealed container collides with the sealed container due to vibration, the shape of the back cover is changed. The present invention relates to a linear compressor that can be cushioned without installing additional parts.

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 plan sectional view showing an example of a 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, and the permanent magnet 33 is installed to reciprocate linear movement therebetween, and the permanent magnet 33 ) Reciprocally drives the piston 4 as it is connected to the piston 4 by the connecting member 34. The inner stator 31 is formed in a cylindrical shape in which 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 side of the frame 2, and then the fixing ring It is fixed by (not shown). The outer stator 32 has a plurality of cores coupled to the coil winding at regular intervals in the circumferential direction, and the cores are installed to surround the outer circumferential surface of the coil winding so that a pair of poles surrounds a portion of the inner circumferential surface of the coil winding. Is provided. 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 body, the inner stator 31 and the outer stator 32 are ignited by alternating N / S poles, and the permanent magnet 33 positioned therebetween is the inner stator 31 and the outer stator. According to the pole change of (32), the reciprocating linear motion while moving by the attraction force or 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.

Recently, linear compressors have been developed to be easily installed in a small space as well as being easily applied to low capacity. However, in the conventional linear compressor and the linear motor applied thereto, the distance that the center of the permanent magnet 33 reciprocates linearly between two poles of the outer stator 32 because of the above-described stroke length of the piston 4. Strictly limited to, it is not suitable for use in a simple structure of low capacity because it uses a number of springs 20 for this purpose.

In the linear compressor as described above, the parts other than the airtight container 1 are assembled into an assembly in one structure, and the linear motor 30 is supported by the airtight container 1 by a plurality of shock absorbing springs (not shown). When vibration is generated due to operation or external impact, the assembly moves and collides with the sealed container 1. At this time, the stopper 40 is mounted on the inner surface of the airtight container 1, but even when the structure is moved, the stopper 40 may be impacted while cushioning the shock, thereby preventing the parts inside the structure from being directly damaged.

However, as the recently developed linear compressor is developed to be easily installed even in a narrow space, the size of the sealed container 1 is also reduced, thereby securing a space for mounting the stopper 40 inside the sealed container 1. There is a difficult problem. Therefore, when the stopper 40 is deleted, the back cover 107 located at the outermost portion of the structure may directly collide with the sealed container 101. Since the back cover 107 is bent at right angles to the plate, it is the shortest. The corner portion of the back cover 107, which maintains the distance, may be deformed by colliding with the sealed container, or the alignment of the parts may be misaligned as the impact is transmitted to the structure, thereby deteriorating operation reliability.

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

In addition, an object of the present invention is to provide a linear compressor that can prevent deformation without installing additional parts by changing the shape of the back cover, even if the structure installed buffered in the sealed container collides with the sealed container by vibration.

The present invention for solving the above problems is a sealed container in which the refrigerant is sucked / discharged; A cylinder accommodated in the sealed container and having a compression space therein; A frame fixed to one end of the cylinder; A piston having one end inserted into the cylinder; A linear motor for reciprocating the piston; A motor cover for axially fixing the linear motor to the frame; At least two mechanical springs supporting the piston in both axial directions; A plurality of buffer springs which elastically support the structure in which the parts are assembled except the sealed container inside the sealed container; And a back cover coupled to the motor cover and provided with a cap-shaped stopper portion protruding in the direction of the closed container so as to hit the closed container by vibrating the one mechanical spring. To provide.

In addition, in the present invention, the stopper portion is characterized in that formed in a circular cap shape in the center of the back cover.

In addition, in the present invention, the stopper portion is characterized in that the corner portion is formed rounded.

In the present invention, the stopper portion is characterized in that the plate material is pressed.

Further, in the present invention, the back cover includes a pair of mounting portions bolted to be symmetrical to the outer circumferential portion of the motor cover, a pair of flat connecting portions extending linearly in the axial direction from the mounting portions, and axially and centered from the flat connecting portions. And a pair of curved connection portions extending in a curved direction, and a stopper portion having a circular cap shape projecting in the axial direction between the curved connection portions.

In addition, in the present invention, the linear motor includes an inner stator installed outside the cylinder, an outer stator provided with one pole between the inner stator and a gap between the inner stator, and a mutual electromagnetic force in the gap between the inner stator and the outer stator. And a plurality of permanent magnets reciprocally linearly moving together with the piston, wherein the plurality of permanent magnets reciprocate linearly in the gap between the inner and outer stators, at their top dead center and at the bottom dead center, at least one permanent magnet. It is characterized by leaving the gap space between the pole of the inner stator and the outer stator.

In addition, in the present invention, the mass (M) of the movable member including the piston and the permanent magnet, the mechanical spring constant (K _mechanical ) defined by the restoring force of the springs, the gas spring constant (defined by the working fluid pressure in the compression space ( K _gas ), which is defined by the magnetic spring constant (K _magnet ) defined by the restoring force of the permanent magnets to match the pole center of the outer stator when the permanent magnets reciprocate linearly in the gap between the inner and outer stators. It is characterized by operating using a defined resonance frequency (f _o ).

Further, in the present invention, the mechanical springs are composed of a first spring installed between the cylinder and the piston flange, and a second spring installed between the piston flange and the stopper portion of the back cover, and the diameters, diameters, and lengths of the springs are: It is characterized in that the mechanical spring constant is made smaller as the magnetic spring constant becomes larger.

The linear compressor of the present invention configured as described above employs a linear motor in which two permanent magnets reciprocally linearly move in the direction of movement between one pole of the inner stator and the outer stator, and the linear compressor employing the linear motor is Since the mechanical spring constant (K _mechanical ) can be designed low by designing the same resonant frequency considering the magnetic spring constant (K _magnet ), only two springs can be configured to support the piston. Since the spring allows the piston to 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 linear compressor according to the present invention, even if the airtight container is formed small, when the structure moves, the stopper portion projecting in a circular cap shape to the back cover located on the exterior of the structure bumps the airtight container to cushion the deformation of the back cover, the alignment of parts ( Aling) can be prevented to ensure operational reliability, and furthermore, the cushioning effect can be increased without additional components, thereby reducing material costs.

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

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

As shown in FIGS. 2 and 3, 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.

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

One example of the linear motor applied to the linear compressor according to the present invention is that the axial ends of the inner stator 131 and the outer stator 132 are connected to each other while the other parts maintain a gap as shown in FIGS. 2 to 4. The magnet unit 133 is disposed between the inner stator 131 and the outer stator 132 to be reciprocated 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, the protrusion 131b having an outer circumferential surface of one end in the axial direction is extended in the axial direction. At this time, since the inner stator 131 is formed longer than the axial length of the cylinder 103 (shown in FIG. 2), 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 has two ends positioned to face the connecting portion 131a and the protrusion 131b of the inner stator 131, and one end portion of the core 132B has a connecting portion 131 of the inner stator 131. The connection part 132a which protrudes toward the inner stator 131 so that it may overlap with 131a is provided, and the other end of the core 132B has the pole which migrates the clearance with the outer peripheral surface of the inner stator 131, and the protrusion 131b. 132b is provided. Furthermore, the connecting portion 132a of the core 132B is formed to press or weld the inner stator 131 by a fastening force acting in an axial direction, or being joined or welded with the connecting portion 131a of the inner stator 131, and in some form. When connected, one end of the inner stator 131 and the outer stator 132 are connected to each other to form a closed loop, thereby eliminating 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. The frame 102 has an inner stator 131 for determining an installation position of the inner stator 131. Is provided with a positioning groove 102h in which the fixing projection 131a of the () part can be accommodated. Of course, when the connected portions 131a and 132a of the inner stator 131 and the outer stator 132 are seated in the decision groove 102h of the frame 102, the frame 102 and the outer stator 132 fill a gap. When the outer stator 132 is coupled to the frame 102 by the motor cover 107, the outer stator 132 contacts the frame 102 with the predetermined force. Press to keep the clamping 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.

5a to 5b 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. 5A to 5B, as power is input to the coil winding 132A, the poles 132b of the inner stator 131 and the outer stator 132 are floated alternately with the N-S poles. Therefore, as shown in FIG. 5A, 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 other hand, as shown in FIG. 5B, when the pole 132b of the outer stator 133 has the S pole, the pole of the magnet 133 pulls the N pole and pushes the S pole of the magnet 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 The center of the (133b) can be seen as 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. 5A and 5B, 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. ), It is preferable that the _mechanical spring constant (K _mechanical ) be designed smaller than before. As a result, in the example of the linear compressor according to the present invention, as described above, the number (n), the diameter (D), the wire diameter (d), and the length (l) of the springs supporting the piston for reciprocating linear movement of the piston in both axial directions. ) Can be designed small, and the parts supporting the springs can be omitted, thereby making it lighter and smaller.

6 is a perspective view showing an example of a back cover applied to the linear compressor according to the present invention.

The linear compressor according to the present invention has 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 as shown in FIG. A structure consisting of a 108, a suction muffler 110, two springs 120 (121, 122), and a linear motor 130 is elastically supported by buffer springs (not shown), so that it can be installed in a narrow installation space. Since the closed container 101 is smaller than that previously applied to the linear compressor. Therefore, when vibration is generated by the operation of the linear motor 130 or an external impact, the structure is easily shaken even by a small vibration while the stopper portion 108a of the back cover 108 described above collides with the hermetic container 101 to be cushioned. Let's do it.

The back cover 108 is press-formed as shown in Figure 6, the stopper portion 108a is a flat portion 108b protruding in the axial direction, and a pair of mounting portions provided on the outside of the flat portion 108b 108c and a pair of planar connections 108d for axially connecting between the planar portion 108b and the mounting portions 108c. Of course, since the back cover 108 is located at the outermost part of the structure, and the sealed container 101 (shown in FIG. 2) is formed in an ellipsoidal shape, as the vibration is generated in the structure, the back cover 108 directly closes the sealed container ( 101: shown in FIG. 2). At this time, since the stopper portion 108a of the back cover 108 collides with the sealed container 101 (shown in FIG. 2), the stopper portion 108a is formed in a circular cap shape at the same time as the corner portion is formed to increase the cushioning effect. It is preferable to form round. In addition, the back cover 108 is inclined to the flat portion 108b and the planar connecting portions 108c so as to be effectively installed in a gentle space portion inside the sealed container 101 (shown in FIG. 2) and to alleviate the collision. More preferably, a pair of curved connectors 108d 'for connecting are provided, but the curved connectors 108d' are formed to extend from the flat portions 108b to the flat connectors 108c in the axial and radial directions. do.

Accordingly, when the plate is bent or punched at least once through press working, the planar connecting portions 108d bent at 90 ° on both sides of the flat portion 108b are made to face in the axial direction, The mounting portions 108c bent at 90 ° to the ends of the planar connecting portions 108d are made to face in the radial direction, and then the stopper portion 108a protrudes in the axial direction on the flat portion 108b, and the flat portion 108b And curved connections 108d 'are made between < RTI ID = 0.0 > Of course, the fastener (h) to which the bolt can be fastened to the mounting parts (108c) is processed separately.

The back cover 108 manufactured as described above has a stopper portion 108a that is the shortest distance from the sealed container 101 (ie, shown in FIG. 2), that is, a rounded corner portion of the stopper portion 108a is provided. Even if the structure vibrates due to the operation, external impact, etc. of FIG. 2, the stopper portion 108a of the back cover 108 collides with the hermetic container 101 (shown in FIG. 2) while the stopper portion 108a and the curved connection portions are formed. 108d ', which can prevent deformation of the back cover 108, and furthermore, the alignment of the sort of parts in which the cylinder, piston, motor cover, back cover, linear motor included in the structure is coaxially located ( Operational reliability can be guaranteed by preventing the aling from twisting.

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

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

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

5a to 5b is a view showing an example of operation of the linear motor applied to the linear compressor according to the present invention.

6 is a perspective view showing an example of a back cover applied to the linear compressor according to the present invention.

Claims (8)

An airtight container into which the refrigerant is sucked / discharged; A cylinder accommodated in the sealed container and having a compression space therein; A frame fixed to one end of the cylinder; A piston having one end inserted into the cylinder; A linear motor for reciprocating the piston; A motor cover for axially fixing the linear motor to the frame; At least two mechanical springs supporting the piston in both axial directions; A plurality of buffer springs which elastically support the structure in which the parts are assembled except the sealed container inside the sealed container; And, And a back cover coupled to the motor cover and provided with a cap-shaped stopper portion protruding in the direction of the sealed container so as to be seated by a single mechanical spring and to vibrate with the sealed container by vibration. The method of claim 1, The stopper portion linear compressor, characterized in that formed in the center of the back cover in a circular cap shape. The method of claim 2, The stopper portion linear compressor, characterized in that the corner portion is formed rounded. The method of claim 1, The stopper portion is a linear compressor, characterized in that the plate material is pressed. The method according to any one of claims 1 to 4, The back cover includes a pair of mounting portions bolted to be symmetrical to the outer circumferential portion of the motor cover, a pair of flat connecting portions extending linearly in the axial direction from the mounting portions, and bent in the axial and central directions from the flat connecting portions. A linear compressor comprising a pair of curved connection parts and a stopper part of a circular cap shape projecting in the axial direction between the curved connection parts. The method according to any one of claims 1 to 4, The linear motor reciprocates together with the piston by the mutual electromagnetic force in the gap between the inner stator installed outside the cylinder, the outer stator provided with a single pole between the inner stator and the gap between the inner stator and the inner stator. Including a plurality of permanent magnets in a linear motion, When a plurality of permanent magnets reciprocate linearly in the gap between the inner and outer stators, at the top dead center and at the bottom dead center, at least one permanent magnet leaves the gap space between the poles of the inner stator and the outer stator. Linear compressor made. The method of claim 6, Mass (M) of movable member including piston and permanent magnet, 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. The method of claim 7, wherein The mechanical springs consist of a first spring installed between the cylinder and the piston flange, and a second spring installed between the piston flange and the stopper portion of the back cover, The diameter, diameter, and length of the springs are designed such that the mechanical spring constant becomes smaller as the magnetic spring constant becomes larger.

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