KR101484325B1 - Linear compressor - Google Patents

Abstract

A linear compressor according to the present invention includes: a cylinder having a compression space therein; A frame integrally formed to extend radially at one axial end of the cylinder; An oil supply passage extending from a lower portion of the frame to an inner peripheral surface of the cylinder; A mounting hole provided on a lower surface of the frame so as to communicate with the oil supply passage; Since the oil supply device is mounted on the mounting hole of the frame and pumps the oil by vibration, the cylinder frame can be integrally formed and the separately manufactured oil supply device can be easily mounted, thereby improving the productivity .

Linear compressor, frame, cylinder, linear motor, oil supply line, oil supply device

Description

[0001] LINEAR COMPRESSOR [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] 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 assembling an oil supply device separately manufactured in an integrally manufactured cylinder frame .

BACKGROUND ART 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 in the cylinder and compresses the refrigerant.

In recent years, since a conventional reciprocal compressor includes a component such as a crankshaft in order to convert the rotational force of the driving motor into the reciprocating linear motion force of the piston, To solve these problems, many linear compressors have been 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.

1 is a plan sectional view showing an example of a linear compressor according to the prior 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 is provided so as to maintain an air gap between the inner stator 31 and the outer stator 32 and to allow the permanent magnet 33 to reciprocate linearly therebetween. The permanent magnet 33 Is connected to the piston 4 by the connecting member 34, and reciprocally drives the piston 4. 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 in the outer peripheral surface of the cylinder 3 so that one axial end of the inner stator 31 abuts on one surface of the frame 2, (Not shown). A plurality of cores are coupled to the coil winding body at regular intervals in the circumferential direction of the coil winding body. The core is provided so as to surround the outer circumferential surface of the coil winding body, Pole. 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 moves reciprocally and linearly by moving by attraction or repulsion 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. [

2 is a side cross-sectional view showing an example of the combination of the cylinder frame and the oil supply device applied to the linear compressor according to the related art.

The conventional linear compressor has a structure in which the permanent magnets 33 reciprocate linearly between the two poles of the inner stator 31 and the outer stator 32 as described above with reference to Fig. The magnetic force is diverged in the vicinity of the pawl of the cylinder 3. In order to prevent the magnetic force from leaking through the frame 2 in which the inner stator 31 and the outer stator 32 are directly supported, The frame 2 is formed by insert molding with aluminum which is a nonmagnetic material on the outer circumferential surface of the cylinder 3 and the oil cylinder 2a is molded like the frame 2 on the lower part thereof. At this time, the oil cylinder 2a is formed into a cylindrical shape.

Therefore, the oil cylinder 2a is machined into a cylinder shape so that components capable of pumping the oil stored in the lower portion of the closed container 1 can be mounted, and an axially long drilling process and an additional grinding process are performed.

However, in the conventional linear compressor, in consideration of the structure of the linear motor 30, the frame 2 is made of aluminum, which is a non-magnetic material, so that the production cost is increased, (2a) is insert-molded with an aluminum material, and then drilling and grinding are added, so that not only the production cost is increased but also the dimensional defect rate is high due to the drilling with the long axial length.

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.

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 in which a frame and a cylinder can be easily manufactured because no magnetic leakage occurs in the vicinity of the frame and the cylinder by changing the linear motor structure.

Another object of the present invention is to provide a linear compressor in which a frame and a cylinder are integrally formed, and a separately manufactured oil supply device can be easily mounted.

According to an aspect of the present invention, there is provided a compressor comprising: a cylinder having a compression space therein; A frame integrally formed to extend radially at one axial end of the cylinder; An oil supply passage extending from a lower portion of the frame to an inner peripheral surface of the cylinder; A mounting hole provided on a lower surface of the frame so as to communicate with the oil supply passage; And an oil supply device mounted on the mounting hole of the frame and pumping the oil by vibration.

Further, in the present invention, the cylinder and the frame are made of castings.

Further, in the present invention, the linear compressor includes a piston for compressing the working gas while linearly reciprocating between the top dead center and the bottom dead center in the cylinder, and a plurality of permanent magnets in the gap between the inner stator and the outer stator, Wherein the outer stator has a pole connected to one end of the inner stator in the outer axial direction and having a gap with the other end in the outer axial direction of the inner stator, Characterized in that at the top dead center and the bottom dead point, at least one permanent magnet deviates from the clearance space portion between the inner stator and the pole of the outer stator when the reciprocating linear motion is performed in the gap between the stator and the 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 disposed between the piston flange and the back cover. And is installed between the first and second plates.

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 oil supply device includes an oil piston, an oil cylinder in which the oil piston is built in and reciprocatingly linearly moves, a pair of caps mounted on both axial ends of the oil cylinder, and an oil piston And a pair of oil springs elastically supported in a direction of the oil springs.

Further, in the present invention, the oil cylinder is characterized by being manufactured by sintering.

Further, in the present invention, the caps are made of a plastic material, and one of the caps is installed so as to fit in the mounting hole of the frame.

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 linear compressor according to the present invention is installed such that the ends of the stator are connected to the frame, the magnetic leaks do not occur to the outside due to the closed loop formed at one end of the stator, Also, since the frame and the cylinder can be integrally manufactured, the production cost can be reduced and the productivity can be increased.

Further, since the linear compressor according to the present invention assembles the mounting hole in the cylinder frame and assembles the plastic injection molding or sintered parts with the oil supply device assembled without any surface processing, the defective rate can be reduced In addition to reducing production costs, it also has the advantage of simplifying the production process and increasing productivity.

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, And the suction valve 105 and the discharge valve assembly 106, the motor cover 107, the back cover 108, the suction muffler 110, the two springs 102, the cylinder 103, the piston 104, (120: 121, 122) and a 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. At this time, the outer stator 132 of the linear motor 130 is fixed between the actual frame 102 and the motor cover 107, and the inner stator 131 is also rotated while fixing the outer stator 132 of the linear motor 130 And 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 It becomes. 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 the form of lamination lamination in the circumferential direction as in the prior art. In order to be connected to the outer stator 132, the inner stator 131 has a connecting portion 131a extending in the radial direction on the outer circumferential surface at one end in the axial direction And a protrusion 131b having an axially extending outer peripheral surface at one end in the axial direction is provided to increase the electromagnetic force. In this case, since the inner stator 131 is formed to be 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, And fixed by a stator 132, which 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 connecting portion 131a and the protruding portion 131b of the inner stator 131, and one end of the core 132B has a connecting portion And a connecting portion 132a protruding in the direction of the inner stator 131 so as to overlap with the outer circumferential surface of the inner stator 131 and the protruding portion 131b of the inner stator 131 are provided at the other end of the core 132B. (132b). Further, the connecting portion 132a of the core 132B is formed so as to press the inner stator 131 by a fastening force that is formed, welded, or axially engaged with the connecting portion 131a of the inner stator 131, The ends of the inner stator 131 and the outer stator 132 are connected to each other to form a closed loop so that there is no possibility that the magnetic flux leaks from the connecting portion of the stator 131 or 132. The pawl 132b of the core 132B has a protruding portion 132b 'which is expanded in both axial directions to widen the area of the surface facing the inner stator 131 in order to increase the electromagnetic force, like the protruding portion 131b of the inner stator 131. [ ) 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 so as to extend in the axial direction. And two laminated core blocks each having a side cross-sectional shape of '┗' and '┛' are assembled to the hull, and then the two core blocks are combined with the coil winding body by a complex joining member and a joining method However, since the core 132B applied to the outer stator 132 of the present invention includes only one pole 132b, it is constituted by one core block laminated with laminations having a side cross-sectional shape of '┛┛' It can be coupled to the hull 132A so that the manufacturing process can be simplified.

The first and second permanent magnets are connected to the inner stator 131 and the outer stator 132, respectively. The first and second permanent magnets 133 and 132 are connected to the first and second permanent magnets 131 and 132, respectively, 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 for determining the installation position of the 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. Of course, when the connected portions 131a and 132a of the inner stator 131 and the outer stator 132 are seated in the crystal grooves 102h of the frame 102, the frame 102 and the outer stator 132 are spaced apart from each other When the outer stator 132 is engaged with the frame 102 by the motor cover 107 and the outer stator 132 abuts against the frame 102 and the inner stator 131 is rotated with a predetermined force So that the fastening force is kept higher. 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, the magnet portion 133 provided with the two permanent magnets 133a and 133b is reciprocated linearly and another restoring force is applied to the magnet portion 133 of the linear motor . 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 in consideration of 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.

FIG. 7 is a side cross-sectional view illustrating an example of a cylinder frame and an oil supply device coupled to the linear compressor according to the present invention, and FIG. 8 is a rear view illustrating an example of a cylinder frame applied to the linear compressor according to the present invention.

As described above, in the linear compressor of the present invention, one end in the axial direction of the inner stator and the stator of the outer stator are connected, and the connected portion of the inner stator and the outer stator is in contact with the frame. The frame 102 and the cylinder 103 can be integrally molded into a magnetic material, for example, as shown in FIGS. 7 to 8 in consideration of the characteristics of the linear motor. Hereinafter, the frame 102 and the cylinder 103, which are integrally made of casting, are referred to as a cylinder frame 102. Of course, the cylinder frame 102 includes a bolt hole 102a to which a motor cover 107 (shown in Fig. 5) for fixing the above-described linear motor 130 (shown in Fig. 5) can be bolted, 130: a wire guide hole 102b through which a wire drawn out from the wire guide hole 130 (shown in Fig. 5) can be passed through is formed separately or integrally at the time of casting.

The linear compressor according to the present invention is a linear compressor in which oil stored under a hermetically sealed container 101 (shown in Fig. 3) is supplied to the cylinder 103 and the piston 104 through an oil supply passage (not shown) 3). ≪ / RTI > Of course, the oil cylinder 142, which is one of the components of the oil supply device 140, may be integrally formed at the time of casting the cylinder frame 102. However, as the mold becomes complicated, the cylinder frame 102 And the oil cylinder 142 are difficult to be molded together with the casting. Therefore, the cylinder frame 102 is formed with a stepped mounting hole 102h at the lower portion of the surface on which the cylinder 103 protrudes so that the oil supply device 140 can be mounted, And assembled to the mounting hole 102h of the frame 102. [

At this time, the oil supply device 140 is configured such that the oil piston 141, the oil cylinder 142, the pair of caps 143, and the pair of oil springs 144 are assembled. The oil piston 141 is a member having a kind of mass, and linearly moves reciprocally inside the oil cylinder 142 while pumping the oil using a pressure difference. The oil cylinder 142 is mounted so that a suction pipe (not shown), which is contained in the oil, communicates with the inside of the oil cylinder 142. The caps 143 are joined in both directions of the oil cylinders 142. Since the caps 143 are made of plastic, there is no need for a separate surface machining like the oil cylinders 142. The oil springs 144 are installed to be supported between the two shafts of the oil piston 141 and the caps 143 so as to elastically support the oil piston 141.

The oil supply device 140 is fitted in the mounting hole 102h of the cylinder frame 102. One of the caps 143 reused with the plastic having the predetermined elasticity is mounted on the casting cylinder frame 102 It can be easily detained because it is fitted in the hole 102h, so that it can be assembled firmly, and operation reliability can be guaranteed.

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.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a linear compressor.

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.

7 is a side cross-sectional view showing an example of a cylinder frame and an oil supply device which are applied to a linear compressor according to the present invention.

8 is a rear view of an example of a cylinder frame applied to a linear compressor according to the present invention.

Claims (10)

A cylinder having a compression space therein; A piston reciprocating linearly between a top dead center and a bottom dead center in a cylinder and compressing the working gas; A frame integrally formed to extend radially at one axial end of the cylinder; A linear motor in which a plurality of permanent magnets reciprocally linearly move the piston by mutual electromagnetic force in a gap between an inner stator and an outer stator; The linear compressor includes springs for elastically supporting the piston at both sides in a reciprocating linear motion direction; An oil supply passage extending from a lower portion of the frame to an inner peripheral surface of the cylinder; A mounting hole provided on a lower surface of the frame so as to communicate with the oil supply passage; And, And an oil supply device mounted to the mounting hole of the frame and pumping the oil by vibration, The outer stator is connected to one end in the outer axial direction of the inner stator and has a pole that forms a gap with another end in the outer axial direction of the inner stator, 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 1, Characterized in that the cylinder and the frame are made of casting. 3. The method of claim 2, 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. delete The method according to claim 1, And the springs are first and second springs which support the piston in both axial directions. 6. The method of claim 5, The linear compressor further includes a back cover installed to keep an axial spacing from 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. The method according to claim 6, Wherein the cylinder has a shorter axial length than the inner stator or the outer stator. The method according to any one of claims 1 to 3 and 5 to 7, The oil supply device includes an oil piston, an oil cylinder that reciprocates linearly with the oil piston incorporated therein, a pair of caps mounted on both ends of the oil cylinder in the axial direction, and a pair of caps that elastically support the oil piston in the axial direction And a pair of oil springs. 9. The method of claim 8, Wherein the oil cylinder is manufactured by sintering. 9. The method of claim 8, The caps are made of plastic, And one of the caps is installed to fit into the mounting hole of the frame.

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