KR20100112473A - Linear compressor and piston applied to it - Google Patents

Abstract

PURPOSE: A linear compressor and a piston applied thereto are provided to miniaturize and lighten the compressor by simplifying the shape of a motor cover and to prevent a magnetic force leak. CONSTITUTION: A linear compressor comprises a cylinder, a linear motor, and a piston. The cylinder has a compression space. The linear motor comprises an inner stator and an outer stator. One end of the inner stator is connected to one end of the outer stator. The connected end of the inner and outer stators is installed on the outer surface of the cylinder. The piston is composed of a head unit(241) inserted into the cylinder and a nonmagnetic flange(242) coupled to the head unit.

Description

Linear compressors and pistons applied thereto {LINEAR COMPRESSOR AND PISTON APPLIED TO IT}

The present invention relates to a piston capable of eliminating the separation / quantity of the joint even if made of different materials, and a linear compressor capable of preventing magnetic leakage by applying the same.

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 cross-sectional view showing an example of a linear compressor according to the prior art, Figure 2 is a side cross-sectional view showing an example of a piston 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) inside an airtight container (1), as shown in FIGS. A structure composed of the motor cover 7, the supporter 8, the back cover 9, the muffler assembly 10, the eight springs 20, and 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 piston 4 is a planar end which is a closed end of the head 4a inserted into the cylinder 3 and an open end which is located outside the cylinder 3 and connected by the permanent magnet 33 and the connecting member 34. It is made of a branch (4b), it is integrally manufactured casting. Of course, the head portion 4a is processed to have a plurality of suction ports 4h for sucking refrigerant into the compression space, and the flange portion 4b is provided with a plurality of holes bolted to the connection member 34. Processed.

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. 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 it is supported by the mass (M: M) of the moving member and the spring constant (K) of the springs (K) of the supporting springs to calculate the MK resonant frequency, the power frequency applied to the linear motor 30 By designing to follow the MK resonant frequency, it is possible to optimize the efficiency of the linear compressor.

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 with 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), it moves by reciprocating force or repulsive force and moves reciprocally linearly. 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, since the permanent magnet reciprocates between two poles of the inner and outer stators, magnetic leakage occurs near two poles of the outer stator and the linear motor efficiency is deteriorated. Therefore, the production cost is high because the frame, which is a member close to one pole of the outer stator, is made of non-magnetic aluminum, and the piston, which is a member close to the other pole of the outer stator, is made of a casting to maintain a predetermined rigidity. Therefore, there is a problem in that magnetic leakage occurs.

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 capable of preventing magnetic leakage between the gaps of stators.

In addition, an object of the present invention is to provide a piston that can be made of different materials to prevent magnetic leakage depending on the position.

In addition, an object of the present invention is to provide a piston that can prevent relative separation / rotation even if made of a different material.

Another embodiment of the present invention for solving the above problems is a cylinder provided with a compression space therein; A linear motor including an inner stator and an outer stator, one end of which is connected to each other in an axial direction, and one connected end of the inner stator and the outer stator mounted on an outer circumferential surface of the cylinder; And, the piston is made of a non-magnetic material coupled to the head portion and the head portion fitted into the cylinder; provides a linear compressor comprising a.

In addition, in the present invention, the piston includes a coupling end of the head portion and the coupling portion of the head portion is coupled to the head portion and the flange portion, the coupling end of the head portion is cylindrical, the coupling end of the flange portion in the coupling end of the head portion It is characterized in that the cross section 'c' shape to surround the / outer peripheral surface.

In addition, in the present invention, the coupling end of the head portion is provided with a plurality of holes in the circumferential direction, the coupling end of the flange portion is characterized in that the coupling to be filled in the coupling end hole of the head portion.

In addition, in the present invention, the linear compressor includes a plurality of permanent magnets reciprocating linear movement with the piston by mutual electromagnetic force in the gap between the inner stator and the outer stator, the outer stator is in the opposite direction to the portion connected to the inner stator The pole has a gap between the inner stator and the permanent magnets in the reciprocating linear motion in the gap between the inner stator and the outer stator, and at least one permanent magnet at the top dead center and the bottom dead center between the inner stator and the outer stator pole. It is characterized by leaving the gap space of the.

Further, in the present invention, the head portion of the piston is characterized in that made of cast iron to maintain a predetermined strength.

In addition, in the present invention, the flange portion of the piston is characterized in that made of aluminum.

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, the back cover is provided to be spaced in the axial direction with the piston; further comprising, the first spring is installed between the piston flange and the back cover, the second spring is installed between the cylinder and the flange of the piston It is characterized by.

On the other hand, one embodiment of the present invention comprises a head portion having a suction port at one end of the membrane; And, coupled to the head portion, provides a piston comprising a; flange portion made of a non-magnetic material.

In addition, in the present invention, the head portion is characterized in that it is made of cast iron to maintain a predetermined strength.

In the present invention, the flange portion is characterized in that made of aluminum.

In addition, in the present invention, the head portion includes a coupling end having a cylindrical shape, the flange portion includes a coupling end having a cylindrical shape surrounding one of the inner / outer peripheral surface of the coupling end of the head portion, the coupling end of the head portion and the coupling end of the flange portion in the radial direction It is characterized in that the assembling grooves and the assembling projections are mated with each other.

In addition, in the present invention, the head portion includes a coupling end having a cylindrical shape, the flange portion includes a coupling end having a cylindrical shape having a 'c' cross-section to surround the inner / outer peripheral surface of the coupling end of the head portion, the coupling end and the flange portion of the head portion The coupling end is characterized in that the insert is coupled.

In addition, in the present invention, the coupling end of the head portion is provided with a plurality of holes along the circumferential direction, the coupling end of the flange portion is characterized in that the coupling to be filled in the coupling end hole of the head portion.

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, in the linear compressor according to the present invention, since one end of the stators is connected to each other, as a closed loop is formed between them, magnetic leakage does not occur to the outside, and even if magnetic leakage occurs around one pole of the stators, the piston is an adjacent member. Since part of the non-magnetic material is made of magnetic leakage can be prevented to increase the efficiency.

In addition, even if the piston according to the present invention is made of a non-magnetic material of the flange portion even if the head portion is made of a magnetic material, as the flange portion of the piston is located close to the gap between the stators, it is possible to prevent magnetic leakage, furthermore, Since the insert is injected to engage the inner and outer circumferential surfaces of the flange portion, there is an advantage that the defect rate can be lowered by minimizing the effect of cooling shrinkage and preventing relative separation / rotation.

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 non-magnetic 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 5 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 a 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. 3 to 5. 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, 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 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. Further, the connecting portion 132a of the core 132B is formed to press or press the inner stator 131 by a fastening force acting in an axial direction, or being molded or welded with the connecting portion 131a of the inner stator 131. Since the ends of the inner stator 131 and the outer stator 132 are connected to each other to form a closed loop, there is no possibility of magnetic flux leaking from 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.

6a to 6b 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. 6A to 6B, as 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. 6A, 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. 6B, when the pole 132b of the outer stator 133 has the S pole, the pole of the magnet portion 133 is attracted and the S pole of the magnet 133 is pushed. 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 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 magnet 133b may be viewed as a moving distance between 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. 6A and 6B, 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 of the moving member ( If M) is kept above a predetermined size, since the influence of the gas spring acting on the movable member can be reduced, the mass M and the gas spring constant K _gas of the movable member are regarded as fixed values. 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), 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 to be small, and parts supporting the springs can be omitted, thereby making it lighter and smaller.

Figure 7 is a side cross-sectional view showing an example of a piston applied to the linear compressor according to the present invention, Figure 8 is a side cross-sectional view showing the head portion before the piston of Figure 7 is insert molded.

One example of a piston applied to the linear compressor of the present invention is a head portion 141 provided at a closed end having a cylindrical inlet 141h, as shown in FIGS. 7 to 8, and an open end of a nonmagnetic material. The flange portion 142 is divided, the head portion 141 may be formed of any material other than the flange portion 142. At this time, since the head portion 141 is in contact with the compression space in the state of being inserted into the cylinder 103 (shown in FIG. 3), it is preferable that the head portion 141 be made of a material having a predetermined strength, and the flange portion 142 of the cylinder 103: Since it is influenced by the electromagnetic force of the linear motor 130 (shown in FIG. 3) in the non-inserted state in FIG. 3, it is preferable to be made of a representative nonmagnetic material to prevent magnetic leakage. For example, the head portion 141 may be made of cast iron, and the flange portion 142 may be made of insert molding on the head portion 141 of aluminum.

More specifically, the coupling portion of the head portion 141 and the flange portion 142 is a cross-section is formed in the shape of the entire cylindrical, the coupling end 141a of the head portion 141 is the inner diameter of the piston 140 The outer diameter is formed larger than the inner diameter and the outer diameter is formed to be the same as the outer diameter of the piston 140, and the coupling end 142a of the flange portion 142 has the inner diameter equal to the inner diameter of the piston 140, and the outer diameter is the head portion. Since it is configured to match the inner diameter of 141, the outer peripheral surface of the coupling end 142a of the flange portion 142 is engaged with the inner peripheral surface of the coupling end 141a of the head portion 141. At this time, the coupling end 141a of the head portion 141 is provided with a plurality of assembling grooves 141b at regular intervals in the circumferential direction on the inner circumferential surface, and the coupling end 142a of the flange portion 142 has a head on the outer circumferential surface. A plurality of assembling protrusions 142b engaged with the assembling grooves 141b of the portion 141 are provided.

Of course, even when cooling shrinkage occurs as the flange portion 142 is insert molded into the head portion 141, the assembling protrusion 142b of the flange portion 142 is removed from the assembling groove 141b of the head portion 141. In order to prevent that, the depth of the assembling groove 141b and the height of the assembling protrusion 142b are preferably determined in consideration of the cooling shrinkage of the coupling end 142a of the flange 142 made of aluminum.

9 is a side cross-sectional view showing another example of a piston applied to the linear compressor according to the present invention, Figure 10 is a side cross-sectional view showing the head portion before the piston of Figure 9 is insert molded.

Another example of the piston applied to the linear compressor of the present invention is configured in the same way as the example of the piston as shown in Figures 9 to 10, the coupling end 241a of the head portion 241 flange portion 242 The coupling end 242a is coupled to wrap. In one example, the head portion 241 is made of cast iron, and the flange portion 242 is insert molded to the head portion 241 with aluminum.

More specifically, the coupling portion 241a, 242a of the head portion 241 and the flange portion 242 is formed in a cylindrical shape, the coupling end 241a of the head portion 241 is formed in a cross-section, The coupling end 242a of the flange portion 242 is formed to have a cross-section 'c' shape is coupled to each other. At this time, the coupling end 241a of the head part 241 is provided with a plurality of holes 241b along the circumferential direction, and the coupling end 242a of the flange part 242 of the head part 241 at the time of insert molding. A fastener 242b filled in the side hole 241b of the coupling end 241a is provided.

Therefore, when the flange portion 242 is insert-molded in the head portion 241, as the aluminum is injected, the coupling end 242a of the flange portion 242 has an inner / outer peripheral surface of the coupling end 241a of the head portion 241. The fastener 242b is formed on the coupling end 242a side of the flange portion 242 while being wrapped and filled in the hole 241b on the coupling end 241a side of the head portion 241. Branch 242 can be prevented from being easily separated / rotated. Thereafter, when the flange portion 242 is cooled and shrunk, the inner diameter of the coupling end 242a of the flange portion 242 decreases and the outer diameter decreases, thereby engaging the coupling end 241a of the head portion 241, and consequently, the head portion. The engaging end 241a of 241 is forcibly fitted with the engaging end 242a of the flange portion 242.

Another example of the piston as described above may be different from the example of the piston without considering the cooling export rate of the material, such as insert molded aluminum, more reliably the relative separation of the head portion 241 and the flange portion 242 Can prevent / rotation.

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

6a to 6b are views showing an example of operation of the linear motor applied to the linear compressor according to the present invention.

Figure 7 is a side cross-sectional view showing an example of a piston applied to the linear compressor according to the present invention.

8 is a side cross-sectional view of the head before the piston of FIG. 7 is insert molded.

Figure 9 is a side cross-sectional view showing another example of a piston applied to the linear compressor according to the present invention.

10 is a side cross-sectional view of the head portion before the piston of FIG. 9 is insert molded.

Claims (15)

A cylinder having a compression space therein; A linear motor including an inner stator and an outer stator, one end of which is connected to each other in an axial direction, and one connected end of the inner stator and the outer stator mounted on an outer circumferential surface of the cylinder; And, And a piston comprising a head portion fitted inside the cylinder and a flange portion of a nonmagnetic material coupled to the head portion. The method of claim 1, The piston includes a coupling end of the head portion and a coupling portion of the flange portion to which the head portion and the flange portion are insert-coupled, The coupling end of the head is cylindrical, The coupling end of the flange portion is a linear compressor, characterized in that the cross section 'c' shape to surround the inner / outer peripheral surface of the coupling end of the head portion. The method of claim 2, The coupling end of the head portion is provided with a plurality of holes along the circumferential direction, The coupling end of the flange portion is a linear compressor, characterized in that coupled to be filled in the coupling end hole of the head portion. The method according to any one of claims 1 to 3, The linear compressor includes a plurality of permanent magnets reciprocating linearly move together with 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. The permanent magnets are linear compressors characterized by one or more permanent magnets leaving the gap space between the poles of the inner and outer stator at the top dead center and the bottom dead center when reciprocating linear motion in the gap between the inner and outer stators. . The method of claim 4, wherein The head portion of the piston is a linear compressor, characterized in that made of cast iron to maintain a predetermined strength. The method of claim 4, wherein A linear compressor, characterized in that the flange portion of the piston is made of aluminum. The method of claim 4, wherein 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. The method of claim 7, wherein And the springs are first and second springs supporting the piston in both axial directions. The method of claim 8, 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. A head portion having a suction port at one end thereof; And, Piston coupled to the head portion, a flange portion made of a non-magnetic material. The method of claim 10, Piston, characterized in that the head portion is made of cast iron to maintain a predetermined strength. The method of claim 11, Piston characterized in that the flange is made of aluminum. The method according to any one of claims 10 to 12, The head portion includes a coupling end that is cylindrical in shape, The flange portion includes a coupling end having a cylindrical shape surrounding one of the inner and outer peripheral surfaces of the coupling end of the head portion, Piston, characterized in that the coupling end of the head portion and the coupling end of the flange portion is provided with an assembling groove and the assembling projection to be joined to each other in the radial direction. The method according to any one of claims 10 to 12, The head portion includes a coupling end that is cylindrical in shape, The flange portion includes a coupling end having a cylindrical shape having a cross-section 'c' to surround the coupling end inner / outer surface of the head portion. The coupling end of the head portion and the coupling end of the flange portion is characterized in that the insert is coupled to the piston. The method of claim 14, The coupling end of the head portion is provided with a plurality of holes along the circumferential direction, The coupling end of the flange portion is a piston, characterized in that coupled to be filled in the coupling end hole of the head portion.

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