Reciprocating compressor

A reciprocating compressor including: a closed container (10); a reciprocating motor (20) having stators and an armature (22) disposed in the air gap between the stators (21) and making a reciprocal movement; a compression unit (30) having a piston (31) combined with the armature (22) of the reciprocating motor and a cylinder fixed inside the closed container (10); a spring unit (50) elastically supporting the armature (22) of the reciprocating motor (20) in a movement direction; and a frame unit (100) supporting the reciprocating motor (20) and the compression unit (30) having a gas hole (111) at a suitable portion thereof. Accordingly, when the armature (22) of the reciprocating motor (20) makes a reciprocal movement, the gas is compressed at the end of the armature (22), so that an increase of a flow resistance is prevented. In addition, in occurrence of an over-stroke of the armature, as the step portion (112) makes a space to prevent the magnet from releasing or damaging, the reliability of the compressor is improved.

TECHNICAL FIELD

The present invention relates to a reciprocating compressor, and more particularly, to a reciprocating compressor that is capable of reducing a flow resistance occurring when a piston makes a reciprocal movement and preventing an armature from damaging in an occurrence of overstroke of the armature.

BACKGROUND ART

In general, a reciprocating compressor is to suck, compress, and discharge a gas while a piston makes a reciprocal movement within a cylinder.

FIG. 1is a vertical-sectional view of a reciprocating compressor of a conventional art.

As shown inFIG. 1, the conventional reciprocating compressor includes a closed container10filled with a lubricant at its bottom and having a suction pipe (SP) and a discharge pipe (DP) communicating with each other therein, a reciprocating motor20fixed inside the closed container10, a compression unit30installed in the closed container10and sucking, compressing and discharging a gas, a frame unit40supporting the reciprocating motor20and the compression unit30, a spring unit50elastically supporting the armature of the reciprocating motor20in a movement direction and inducing a resonance, and a lubricant feed unit (not shown) mounted at the frame unit40and feeding a lubricant to the reciprocating motor20and the compression unit30.

The reciprocating motor20includes a stator21consisting of an inner stator21A and an outer stator21B and an armature22inserted in an air gap between the inner stator21A and the outer stator21B and making a reciprocating movement along with a piston31(to be described).

The armature22includes a magnet support member22A inserted in the air gap between the inner stator21A and the outer stator21B and combined with the piston31of the compression unit30, and magnets22B fixed at the outer circumferential surface of the magnet support member22A at regular intervals so as to be positioned in the air gap between the inner stator21A and the outer stator21B.

The compression unit30includes the piston31making a reciprocal movement by being combined to the magnet support member22A of the reciprocating motor20, a cylinder32fixed at a front frame41(to be described) so that the piston31is slidably inserted thereto, and forming a compressive space32aalong with the piston31, a suction valve33mounted at the front end of the piston31, opening and closing a gas hole31bof the piston31to limit suction of a gas, and discharge valve assembly34mounted at the front end face of the cylinder32to cover the compressive space and limit discharging of a compressed gas.

A gas flow passage31acommunicating with the suction pipe (SP) is formed long inside the piston31to a predetermined depth and a gas hole31bis formed connected to the gas flow passage31a, penetrating the front end face of the piston31.

The frame unit40includes a front frame41supporting contacting the front side of the inner stator21A and the outer stator21B, with which the cylinder32is insertedly combined, a middle frame42supportedly contacting the rear side of the outer stator21B, and a rear frame43combined with the middle frame42to support the rear end of an outer spring52.

The spring unit50includes an inner spring51inserted at the outer circumference of the cylinder32in the axial direction so that both ends thereof are respectively supported at the front face of a combining portion of the magnet support member22A and the piston31and at the corresponding inner face of the front frame41, and an outer spring52, both ends of which are respectively supported at the rear face of the combining portion of the magnet support member22A and the piston31and a corresponding front face of the rear frame43.

The operation of the conventional reciprocating compressor constructed as described above will now be explained.

When a power is applied to a winding coil21C mounted at the outer stator21B and a flux is generated between the inner stator21A and the outer stator21B, the armature22positioned at the air gap between the inner stator21A and the outer stator21B is moved in the flux direction to continuously make a reciprocal movement by virtue of the spring50, and accordingly, the piston31combined with the armature22makes a reciprocal movement with the cylinder32, so that the volume of the compressive space32ais changed and a coolant gas is sucked into the compressive space32a, compressed therein and discharged therefrom.

In the sucking stroke of the piston, the coolant gas is sucked into the closed container10through the suction pipe (SP), passes through a gas flow passage31aand the gas hole31bof the piston31and opens the suction valve33so as to be sucked into the compressive space32a, and in a compression stroke of the piston, the gas is compressed to a predetermined pressure and then discharged through the discharge pipe (DP) by opening the discharge valve assembly34. The series of processes are repeatedly performed.

However, the conventional reciprocating compressor has the following problem. That is, as shown inFIG. 2A, since the front frame41supporting the inner stator21A and the outer stator21B is closed, the compressed gas works as a flow resistance to the behavior of the armature22which is reciprocally moved. Thus, due to the flow resistance, the armature22fails to proceed to a desired position, resulting in that the stroke of the piston31is shortened, degrading an efficiency of the compressor.

In addition, as shown inFIG. 2B, in case where the front frame41supporting both the inner stator21A and the outer stator21B is disposed very close to the armature22, when an overstroke of the armature22occurs, there is a high possibility that the armature22collides with the rear face of the front frame41to damage the magnet22B or a flux leakage between the two stators21A and21B is increased. Meanwhile, in case where the front frame41supporting both the inner stator21A and the outer stator21B is disposed at a distance from the armature22, the piston31, the rear frame43and the closed container10should be lengthened, causing problems that the material expense of the high-priced magnet is increased, the compressor is enlarged.

DISCLOSURE OF THE INVENTION

Therefore, an object of the present invention is to provide a reciprocating compressor that is capable of reducing a flow resistance caused due to compression of a coolant gas generated at a place other than a compression unit when an armature is reciprocally moved.

Another object of the present invention is to provide a reciprocating compressor that is capable of preventing an armature from colliding with a frame in occurrence of an overstroke of the armature, reducing a flux leakage between an inner stator and an outer stator and accomplishing a compact size compressor.

To achieve these objects, there is provided a reciprocating compressor including: a closed container in which a suction pipe and a discharge pipe communicate with each other; a reciprocating motor having a stator which consists of an inner stator and an outer stator fixed with a predetermined air gap inside the closed container and an armature disposed in the air gap between the two stators and making a reciprocal movement; a compression unit having a piston combined with the armature of the reciprocating motor to make a reciprocal movement along with the armature and a cylinder fixed inside the closed container into which the piston is slidably inserted to form a compressive space; a spring unit elastically supporting the armature of the reciprocating motor in the movement direction of the armature and inducing a resonance; and a frame unit supporting the reciprocating motor and the compression unit and having a gas hole at a certain portion thereof.

To achieve the above objects, there is also provided a reciprocating compressor including: a closed container in which a suction pipe and a discharge pipe communicate with each other; a reciprocating motor having a stator which consists of an inner stator and an outer stator fixed with a predetermined air gap inside the closed container and an armature disposed in the air gap between the two stators and making a reciprocal movement; a compression unit having a piston combined with the armature of the reciprocating motor to make a reciprocal movement along with the armature and a cylinder fixed inside the closed container into which the piston is slidably inserted to form a compressive space; a spring unit elastically supporting the armature of the reciprocating motor in a movement direction and inducing a resonance; and a frame unit having a contact part simultaneously contacting each stator of the reciprocating motor to support the reciprocating motor and the compression unit and a noncontact part at which a step portion is formed concave

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

A reciprocating compressor in accordance with a preferred embodiment of the present invention will now be described with reference to the accompanying drawings.

FIG. 3is a vertical-sectional view showing an example of a reciprocating compressor in accordance with a preferred embodiment of the present invention,FIG. 4is a schematic sectional view showing a major part of the reciprocating compressor in accordance with the preferred embodiment of the present invention,FIG. 5Ais a schematic sectional view showing an operational state of an armature of the reciprocating compressor in accordance with the preferred embodiment of the present invention, andFIG. 5Bis a schematic sectional view showing an operational state of an armature of the reciprocating compressor in accordance with the preferred embodiment of the present invention.

As shown in the drawings, a reciprocating compressor of the present invention includes a closed container10filled with a lubricant at its bottom and having a suction pipe (SP) and a discharge pipe (DP) communicating with each other therein, a reciprocating motor20fixed inside the closed container10, a compression unit30installed in the closed container10and sucking, compressing and discharging a gas, a frame unit100supporting the reciprocating motor20and the compression unit30, a spring unit50elastically supporting the armature of the reciprocating motor20in a movement direction and inducing a resonance, and a lubricant feed unit (not shown) mounted at the frame unit100and feeding a lubricant to the reciprocating motor20and the compression unit30.

The reciprocating motor20includes a stator21consisting of an inner stator21A and an outer stator21B and an armature22inserted in an air gap between the inner stator21A and the outer stator21B and making a reciprocating movement along with a piston31(to be described).

The armature22includes a magnet support member22A inserted in the air gap between the inner stator21A and the outer stator21B and combined with the piston31of the compression unit30, and magnets22B fixed at the outer circumferential surface of the magnet support member22A at regular intervals so as to be positioned in the air gap between the inner stator21A and the outer stator21B.

The compression unit30includes the piston31making a reciprocal movement by being combined to the magnet support member22A of the reciprocating motor20, a cylinder32fixed at a front frame110(to be described) so that the piston31is slidably inserted thereto, and forming a compressive space32aalong with the piston31, a suction valve33mounted at the front end of the piston31, opening and closing a gas hole31bof the piston31to limit suction of a gas, and discharge valve assembly34mounted at the front end face of the cylinder32to cover the compressive space and limit discharging of a compressed gas.

A gas flow passage31acommunicating with the suction pipe (SP) is formed long penetrating inside the piston31to a predetermined depth and a gas hole31bis formed connected to the gas flow passage31a, penetrating the front end face of the piston31.

The frame unit100includes a front frame110supportingly contacting the front side of the inner stator21A and the outer stator21B, with which the cylinder32is insertedly combined, a middle frame120supportedly contacting the rear side of the outer stator21B, and a rear frame130combined with the middle frame120to support the rear end of an outer spring52.

With reference toFIG. 4, the front frame110is formed in a disk type having a through hole (without a reference numeral) at the center thereof into which the cylinder32is inserted. The front frame110includes a contact part (a) contacting both the inner stator21A and the outer stator21B and a noncontact part (b), which the inner stator21A and the outer stator21bdo not contact, includes gas holes111formed on the same circumference.

The gas holes111are formed at a portion of facing the armature22in the movement direction in the air gap between the inner stator21A and the outer stator21B, and the diameter (D1) of the gas hole111is preferably the same as or greater than the interval (D2) of the air gap.

At the inner side of the front frame110, a step portion112, which has a ring shape when viewed from the front side, is formed concave, having an annular form when viewed from the front side, to prevent the end portion of the armature22from colliding with the inner face of the front frame110in occurrence of an overstroke of the armature22.

The step portion112is formed at a portion where the gas hole111is formed of the inner face of the front frame110corresponding to the front end of the armature22, that is, at the noncontact part (b) with a predetermined depth which does not contact the inner stator21A and the outer stator21B.

In order to avoid a possible collision between the armature22and the front frame110in occurrence of an overstroke of the armature22, the distance (L1) from the bottom of the step portion112to the corresponding front end of the armature22is longer than the distance (L2) from the inner face of a flange part31C where the armature22and the piston are combined with each other to the most adjacently corresponding rear end of the inner stator21A.

In order to prevent a flux leakage to the front frame110, it is preferred that the distance (L1) from the bottom of the step portion112and its corresponding front ends of the stators21A and21B is the same or longer than the interval (D2) of the air gap between the two stators21A and21B.

The spring unit50includes an inner spring51inserted in the axial direction of the piston31into the outer circumference of the cylinder32so that both ends thereof are respectively supported by the front face of the combining portion of the magnet support member22A and the piston31and by the corresponding inner face of the front frame110, and an outer spring52of which both ends are respectively supported by the rear face of the combining portion of the magnet support member22A and the piston31and its corresponding front face of the rear frame43.

With reference toFIG. 6, the flange part31cis formed at the end of the rear side of the piston31so as to be combined with the magnet support member22A of the armature22. Gas holes31dmay be formed on the same circumference at equal intervals so that gas at both sides can be smoothly circulated.

Several gas holes22amay be formed at the magnet support member22A to reduce a flow resistance occurring at the rear side when the armature is moved reciprocally.

The same elements as those of the conventional art are given the same reference numerals.

The operational effect of the present invention will now be described.

When a power is applied to the winding coil21C of the reciprocating motor20, the armature22makes a reciprocal movement linearly along with the piston31. As the piston31is moved reciprocally within the cylinder32, the pressure of the compressive space32ais varied, so that the coolant gas is sucked into the compressive space32a, compressed up to a certain pressure and discharged. The series of processes are repeatedly performed.

A space (A) is formed around the front end portion of the armature22by the inner stator21A, the outer stator21B and the front frame110, so that when the armature22is reciprocally moved, the pressure of the space (A) is heightened which may cause a flow resistance to the reciprocal movement of the armature.

In this respect, however, since gas holes111are formed at the front frame110, when the armature22is moved forwardly, the gas filled in the space (A) is exhausted outside the compression unit30through the gas holes111. Thus, a flow resistance to the reciprocal movement of the armature is reduced, so that the output-to-input of the motor can be increased, resulting in an improvement of the efficiency of the compressor.

FIG. 6is a schematic sectional view showing a major part of a modification of the reciprocating compressor in accordance with the preferred embodiment of the present invention.

With reference toFIG. 6, gas holes22aand31dare respectively formed at the magnet support member22A and the flange part31cof the piston, the rear side of the armature22, so that when the armature22is reciprocally moved, the gas filled inside and outside the armature freely flows to each other, and thus, a flow resistance due to the gas generated at the rear side of the armature22is reduced and an efficiency of the compressor is improved.

In case that an overstroke occurs that the armature22and the piston31forwards excessively due to a control error in reciprocal movement of the armature, there is a possibility that the front end portion of the armature22collides the inner face of the front frame110. For such a case, as shown inFIG. 5B, the depth of the step portion112is suitably adjusted when formed at the front frame110, such that before the front end portion of the armature22collides the inner face of the front frame110, the combining portion of the armature22and the piston31, that is, the flange part31cof the piston, first collides the rear face of the inner stator21A to limit the forward movement of the armature21. Accordingly, the magnet22B is prevented from releasing from the magnet support member22A or damaging.

In addition, thanks to the step portion112of the front frame110, the front frame110is positioned at a distance from each pool part of the inner stator21A and the outer stator21B even without extending the horizontal length of the compressor, so that the flux leakage through the front frame110is reduced and the efficiency of the reciprocating motor is improved.

A reciprocating motor in accordance with another embodiment of the present invention will now be described with reference toFIGS. 7 and 8.

FIG. 7is a vertical-sectional view showing another modification of the reciprocating compressor in accordance with the preferred embodiment of the present invention; andFIG. 8is a vertical-sectional view showing a major part of the modification of the reciprocating compressor in accordance with the preferred embodiment of the present invention.

Unlike the above described example in which the reciprocating motor20is disposed outer circumference of the compression unit30, in this modification, as shown inFIG. 7, a reciprocating motor220and a compression unit230are disposed at a predetermined interval in the forward and backward direction and mechanically connected and supported by a frame unit240.

The frame unit240includes a front frame241, a first and a second middle frames242A and242B and a rear frame243.

A cylinder232into which a piston231is slidably inserted is fixed at the front frame241.

An outer stator221B of the reciprocating motor220is fixed between the second middle frame242B and the rear frame243, and a contact portion (a) is formed at the rear frame243by being supportedly contacted with the inner stator221A and the outer stator221B.

At the noncontact portion (b) corresponding in the movement direction of the armature222to the air gap between the inner stator221A and the outer stator221B, gas holes243ahaving an inner diameter (D1) greater than the length (D2) of the air gap are formed on the same circumference.

A step portion243bincluding gas holes243ais formed concavely in a ring shape at the noncontact portion (b).

As for the depth of the step portion243b, likewise in the above described example, it is preferred that the distance (L1) from the bottom of the step portion243ato the rear end of the armature222is longer than the distance (L2) from the combining portion of the armature222and the piston231, that is, the flange part231c, to the front end of the inner stator221A.

In this modification, a plurality of gas holes (not shown) may be formed at the flange part231cof the piston231for combining the armature222and the piston231and at the magnet support member222A.

In this manner, the space formed by the inner stator, the outer stator and the rear frame communicates with the outside through the gas holes, so that a flow resistance caused as the pressure in the space goes up during the reciprocal movement of the armature can be reduced.

In addition, in occurrence of an overstroke of the armature and the piston, thanks to the step portion of the rear frame, the combining portion of the armature and the piston first collides with the front end of the inner stator before the end portion of the armature collides with the inner face of the rear frame, preventing the armature from colliding. Thus the magnet is prevented from releasing or damaging and the reliability of the compressor is improved.

Moreover, since the interval between each stator and the rear frame is widened to a degree, the flux leakage is prevented through the rear frame, resulting in that the performance of the reciprocating motor is improved and the efficiency of the compressor is also improved.

As so far described, according to the reciprocating compressor of the present invention, the frame unit supporting the reciprocating motor and the compression unit includes at least one frame to support both the inner stator and the outer stator and the gas hole and the step portion are formed facing the air gap between the two stators.

Accordingly, when the armature of the reciprocating motor makes a reciprocal movement, the gas is compressed at the end of the armature, so that an increase of a flow resistance is prevented, and the efficiency of the compressor is heightened.

In addition, in occurrence of an overstroke of the armature, as the step portion makes a space to prevent the magnet from releasing or damaging, the reliability of the compressor is improved.

Moreover, the interval between the frame and each stator is widened to a degree to cut off a flux leakage, so that the efficiency of the compressor can be improved.