KR20100112478A - Linear compressor and motor cover applied to it - Google Patents

Abstract

PURPOSE: A linear compressor and a motor cover applied to the same are provided to reduce the weight and the volume of a linear motor through the structure change of a linear motor. CONSTITUTION: A linear compressor comprises a cylinder, a frame, an inner stator, an outer stator, and a motor cover(207). The cylinder comprises a compression space. The frame is extended to one end of the axial direction of the cylinder in a radial direction. The inner stator is installed outside the cylinder. The outer stator is installed in order to keep a gap outside the inner stator. The motor cover couples the outer stator to the frame using a bolt and comprises a ring-shaped coupling plate(207A) and a plurality of reinforcement ribs(207B,207C). The coupling plate supports only a part of the outer circumference surface of one end of the axial direction. The reinforcement rib is projected from the coupling plate.

Description

LINEAR COMPRESSOR AND MOTOR COVER APPLIED TO IT}

The present invention relates to a motor cover that can maintain rigidity even if the material is saved, and a linear compressor capable of firmly fixing the stators at once 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 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.

2 is a perspective view showing an example of a motor cover applied to the linear compressor according to the prior art.

Motor cover 7 applied to the conventional linear compressor is formed in a disk shape as shown in Figures 1 to 2, the through hole (H) so that the piston (5) and the inner stator (31) can pass through the center Is provided, and around the supporter 8 is provided with projection-shaped spring mounting portions 7a capable of supporting the springs 21 therebetween. Of course, the motor cover 7 is provided with frame fasteners 2b for fastening by the frame 2 and the long bolts, and back cover fasteners 7c for fastening the bolts with the back cover 9 are also provided. It is provided. At this time, the motor cover 7 preferably has a predetermined area that can cover most of the axial one end of the outer stator 32, which forms not only the spring mounting portions 7a but also the frame 2 and the motor cover. This is to ensure the strength that can withstand the concentrated load applied to the fasteners 7b for the frame even if the long bolts are fastened between the (7).

Therefore, since the conventional linear compressor manufactures the motor cover 7 so as to cover all the axial ends of the outer stator 32, there is a problem in that the production cost increases as a lot of materials are used.

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 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 and a motor cover applied thereto, which can reinforce strength even if the area is reduced by changing the shape of the motor cover to firmly fix the linear motor.

In one embodiment of the present invention for solving the above problems, a compression space provided inside the cylinder; A frame extending radially at one axial end of the cylinder; An inner stator installed outside the cylinder; An outer stator installed to maintain a gap outside the inner stator; A bolt-fastening outer stator is attached to the frame, and a ring-shaped fastening plate supporting only a portion of an outer circumference of one end of the outer stator in axial direction, and a plurality of reinforcing ribs protruding in the axial direction on the inner and outer circumferential surfaces of the fastening plate. It provides a linear compressor comprising a; motor cover.

Further, in the present invention, the linear compressor reciprocates linearly by a mutual electromagnetic force in a gap between a piston for compressing a working fluid while reciprocating linear motion between a top dead center and a bottom dead center inside a cylinder, and an inner and an outer stator. It further comprises a plurality of permanent magnets, the outer stator is connected to the outer axial end of the inner stator, the outer stator has a pole which makes a gap with the other end of the outer axial direction, the permanent magnets between the iterator and the outer stator When the reciprocating linear motion in the gap of the, at the top dead center and the bottom dead center, at least one permanent magnet is characterized by being out of the gap space between the pole of the inner and outer stator.

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

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

In addition, in the present invention, the linear compressor further comprises a back cover installed to be spaced in the axial direction with the piston, the first spring is installed between the piston flange and the back cover, the second spring is the flange of the cylinder and the piston Characterized in that installed between.

In addition, in the present invention, the reinforcing ribs are formed on the entire outer circumferential surface of the motor cover, or characterized in that formed only in a partial section provided with fasteners for fastening bolts of the inner circumferential surface of the motor cover.

On the other hand, in another embodiment according to the present invention, a ring-shaped fastening plate provided with a plurality of fasteners; An outer circumferential rib for protruding along the outer circumferential surface of the fastening plate; And, it provides a motor cover comprising a; inner peripheral reinforcing ribs protruding on the inner peripheral surface of the fastening plate.

In addition, in the present invention, the inner circumferential reinforcing rib is characterized in that formed only in a predetermined section provided with bolt holes of the inner circumferential surface of the fastening plate.

In addition, in the present invention, the fastening plate is characterized in that the portion provided with the bolt holes includes an extension protruding in the inner / outer circumferential direction.

In addition, in the present invention, the inner / outer reinforcing rib is characterized in that it comprises a curved portion protruding along the inner / outer peripheral surface of the expansion portion of the fastening plate.

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

In addition, the linear compressor according to the present invention and the motor cover applied thereto can reduce the area of the fastening plate that is in contact with the stator because the portion supporting the springs can be deleted, thereby reducing the material cost and production cost, and the long bolt fastening Therefore, even if a concentrated load is applied to the fasteners of the fastening plate, additional reinforcing ribs are formed in the portion to which the concentrated load is applied, thereby ensuring the strength, preventing deformation, and stably fixing the stators, thereby improving operational reliability. There is an advantage to be secured.

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 the frame magnetizes as the magnetic flux leaks through the gap existing in the pole on the cylinder side. At least one had to be made of a 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 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, 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. 4), the inner stator is hardly fixed to the outer circumferential surface of the cylinder as in the past, and the outer stator 131 is outer to compensate for this. Although fixed by the stator 132, it will be described in detail below.

The outer stator 132 is installed to surround the coil winding body 132A, in which the coil is wound in the circumferential direction, and a portion excluding the inner circumferential surface of the coil winding body 132A at regular intervals in the circumferential direction of the coil winding body 132A. Consisting of a plurality of cores (132B), the core (132B) is configured such that only a portion of the lamination having a lateral 'cross section' is laminated in the circumferential direction. At this time, the core 132B is provided with two ends positioned to face the connecting portion 131a and the protrusion 131b of the inner stator 131, and one end of the core 132B has a connecting portion 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 abut the frame 102, the magnetic force is not limited to the frame ( 102, the frame 102 and the cylinder 103 does not need to be manufactured by a non-magnetic material such as aluminum by injection molding or the like, and is a magnetic material, for example, easily integrated into a casting by cast iron. Can be formed.

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 133 moves in the opposite direction so that the two permanent magnets 133b are positioned between the inner stator 131 and the pole 132b of the outer stator 132, but the center of the second permanent magnet 133b is similarly not the center of the second permanent magnet 133b. The inner permanent portion 132b 'of the outer stator 132 moves to a range that does not deviate, and thus the first permanent magnet 133a moves out of the inner end portion 132b' of the outer stator 132 as the inner stator ( The gap space between the 131 and the pawl 132b of the outer stator 132 is completely out of the gap. That is, the moving distance of the magnet part 133, that is, the stroke of the piston 104 is the second permanent magnet from the point where the center of the first permanent magnet 133a is located at the end of the outer protrusion 132b 'of the outer stator 132 It can be seen that the center of the 133b is the moving distance between the points located at the end of the inner protrusion 132b 'of the outer stator 132.

However, in the linear motor according to the present invention as described above, while the magnet part 133 having the two permanent magnets 133a and 133b as described above reciprocates linearly, another restoring force is applied to the magnet part 133 of the linear motor. It will work. 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 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 to the end.

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. The mechanical spring constant (K _mechanical ) defined as the restoring force, the spring constant (K _gas ) defined as the pressure of the gas drawn into the compression space, and the restoring force acting as the center of the permanent magnet leaves the stator poles. The defined magnetic spring constant K _magnet can be adjusted. At this time, the mass (M) of the moving member is determined for each product, the gas spring constant (K _gas ) is also determined according to the type of refrigerant, the gas spring constant (K _gas ) is easy to change depending on the load, but the mass (M) of the moving member ), The mass M of the movable member and the gas spring constant K _gas are regarded as fixed values because the influence of the gas spring acting on the movable member can be reduced. Therefore, in order to adjust the power source frequency f to the resonance point, it is preferable to adjust the _mechanical spring constant K _mechanical and the magnetic spring constant K _magnet , and as described above, the magnetic spring constant K _magnet as compared to the conventional one. In consideration of this, it is preferable that the _mechanical spring constant (K _mechanical ) be smaller than the conventional design. As a result, in the example of the linear compressor according to the present invention, as described above, the number (n), 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.

7 and 8 are perspective views showing the first and second embodiments of the motor cover applied to the linear compressor according to the present invention.

Since the linear compressor according to the present invention is supported between the cylinder, the piston flange, and the back cover as only two springs are applied as described above, a part capable of supporting the springs on the motor cover becomes unnecessary, and thus, the motor has been reduced. The area of the cover can be reduced. Therefore, the first embodiment of the motor cover that can be applied to the linear compressor of the present invention is a hole (H) formed in the relatively center as shown in FIG. ) Is composed of a ring-shaped fastening plate 107A and an outer circumferential reinforcing rib 107B projecting in the axial direction on the outer circumferential surface of the fastening plate 107A.

More specifically, the fastening plate 107A is installed to be in contact with the outer peripheral portion of the axial end of the outer stator 132 (shown in FIG. 5). It may be designed not to cover the poles 132b (shown in FIG. 3) of the outer stator 132 (shown in FIG. 3). At this time, the fastening plate 107A is formed with a frame 102 (shown in FIG. 3) and four frame fasteners 107a fastened with long bolts at regular intervals in the circumferential direction, and the back cover 108: FIG. 3. And two back cover fasteners 107b bolted to each other are formed at both sides. Of course, the concentrated load acts as the bolt is fastened to the fasteners 107a and 107b of the fastening plate 107A, and the inner stator 131 between the frame 102 and the motor cover 107 is shown. Frame fasteners of the motor cover 107 because a larger concentrated load acts on the frame fasteners 107a of the motor cover 107 to fix the outer stator 132 and the outer stator 132 (shown in FIG. 3) all at once. In order to distribute the concentrated load acting on the 107a, the fastening plate 107A is provided with an extension 107c extending in the circumferential direction at the portion where the frame fasteners 107a are formed, and the outer reinforcing rib 107B. The curved surface portion 107d protrudes along the expansion portion 107c of the fastening plate 107A.

On the other hand, the second embodiment of the motor cover that can be applied to the linear compressor of the present invention, as shown in Figure 8, protruding in the axial direction along the ring-shaped fastening plate 207A and the outer peripheral surface of the fastening plate 207A An outer circumferential reinforcing rib 207B and an inner circumferential reinforcing rib 207C protruding in the axial direction on the inner circumferential surface of the fastening plate. Of course, the second embodiment of the motor cover is formed in the same manner as the first embodiment of the motor cover, but the inner circumferential reinforcing rib 207C is added. Therefore, in the second embodiment of the motor cover 207, since the cross section is formed in the shape of a beam having a 'c' shape, the motor cover having a 'b' shape even when a bending stress occurs due to the concentrated load due to the fastening of the long bolts is generated. As the secondary area moment value I becomes larger than that of the first embodiment of the present invention, the bending stress appears to be smaller, and not only to distribute the load but also to prevent deformation.

More specifically, the fastening plate 207A is provided with frame fasteners 207a and back cover fasteners 207b, and the inner and outer circumferences at the part where the frame fasteners 207a in which a larger concentrated load is distributed are provided. Expansion portion 207c extending in the direction is provided. The inner and outer reinforcing ribs 207B and 207C are provided with curved portions 207d and 207e protruding in the axial direction along the expansion portion 207c of the fastening plate 207A. At this time, the inner circumferential reinforcing rib 207C may protrude less in the axial direction than the outer circumferential reinforcing rib 207B, and frame fasteners 207a to which a concentrated load is applied rather than being formed on the entire inner circumferential surface of the fastening plate 207A. ) May be formed to protrude only in the portion provided.

9A and 9B are graphs showing a stress distribution acting on a conventional motor cover and a motor cover second embodiment of the present invention.

The conventional motor cover is subjected to a concentrated load on the frame fastener as shown in Figure 9a, while the second embodiment of the motor cover of the present invention is a strength reinforcement due to the inner / outer reinforcement ribs as shown in Figure 9b Because of this, it can be seen that the concentrated load acting on the frame fastener is dispersed. Therefore, the motor cover of the present invention can distribute the concentrated load even if long bolts are installed to fix the linear motor, thereby preventing failure due to deformation as well as ensuring operational reliability. Of course, in the second embodiment of the motor cover of the present invention, the concentrated load also acts on the back cover fastener, even if deformation occurs, it does not significantly affect the fixing of the back cover.

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 perspective view showing an example of a motor cover 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.

7 and 8 are a perspective view showing the first and second embodiments of the motor cover applied to the linear compressor according to the present invention.

9A and 9B are graphs showing the stress distribution acting on the conventional motor cover and the second embodiment of the motor cover of the present invention.

Claims (10)

A cylinder having a compression space therein; A frame extending radially at one axial end of the cylinder; An inner stator installed outside the cylinder; An outer stator installed to maintain a gap outside the inner stator; And, A motor cover including a ring-shaped fastening plate which bolts the outer stator to the frame and supports only a portion of the outer circumference of one end surface of the outer stator, and a plurality of reinforcing ribs protruding in the axial direction on the inner and outer circumferential surfaces of the fastening plate. Linear compressor comprising a. The method of claim 1, The linear compressor includes a piston for compressing the working fluid while reciprocating linear motion between the top dead center and the bottom dead center inside the cylinder, and a plurality of permanent magnets for reciprocating linear motion of the piston by mutual electromagnetic force in the gap between the inner and outer stators. Including more, The outer stator has a pawl connected to the outer axial end of the inner stator and spaced apart from the outer axial end of the inner stator, Permanent magnets are characterized in that when the reciprocating linear motion in the gap between the iterator and the outer stator, at the top dead center and the bottom dead center, at least one permanent magnet is out of the gap space between the pole of the inner and outer stator Linear compressor. The method of claim 2, 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 3, And the springs are first and second springs supporting the piston in both axial directions. The method of claim 4, wherein The linear compressor further includes a back cover installed to be spaced axially with the piston; 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. 6. The method according to any one of claims 1 to 5, Reinforcing ribs are formed on the entire outer circumferential surface of the motor cover, or the linear compressor, characterized in that formed in only a partial section of the fastening fastening fasteners of the inner circumferential surface of the motor cover. Ring-shaped fastening plate provided with a plurality of fasteners; An outer circumferential rib for protruding along the outer circumferential surface of the fastening plate; And, Motor cover comprising a; reinforcing ribs protruding on the inner peripheral surface of the fastening plate. The method of claim 7, wherein The inner circumferential rib has a motor cover, characterized in that formed only in a predetermined section provided with bolt holes in the inner circumferential surface of the fastening plate. The method of claim 7, wherein Fastening plate is a motor cover, characterized in that the portion provided with bolt holes protruding in the inner / outer direction. 10. The method of claim 9, The inner / outer reinforcing rib includes a curved surface protruding along the inner / outer circumferential surface of the expansion plate of the fastening plate.

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