Compressor-diagnosing apparatus and method

Abstract

The present invention relates to an apparatus and method for diagnosing a compressor. A compressor-diagnosing apparatus according to an embodiment of the present invention comprises: a sensor unit attached to the outer surface of a body shell of a compressor to detect vibration generated in the compressor; a signal detection unit which receives, from the sensor unit, a vibration detection signal corresponding to vibration detection; and a diagnosis unit which extracts a signal of a modal component of the body shell including a signal that has been excited by a collision vibration component as a result of the removal of a signal that has been excited by a rotational vibration component from the vibration detection signal received from the signal detection unit, and which diagnoses whether internal components of the compressor are worn based on the extracted signal of the modal component of the body shell. According to the present invention, the internal condition of a compressor can be conveniently diagnosed without disassembling or dismantling the compressor.

Description

Compressor diagnostic device and method

[0001] The present invention relates to an apparatus and method for diagnosing a compressor.

[0002] Generally, a compressor refers to a mechanical device used for generating high pressure or transporting high-pressure fluids. Among these, compressors applied to refrigeration cycles, such as those in refrigerators or air conditioners, perform the function of compressing refrigerant gas and transferring it to the condenser.

[0003] Among these compressors, the rotary scroll compressor is configured such that a fixed scroll (non-rotating scroll) is fixed in the internal space of the case, and a rotary scroll is engaged with the fixed scroll to perform a rotary motion.

[0004] When the rotating scroll rotates relative to the stationary scroll, the suction, gradual compression, and discharge of refrigerant gas are continuously and repeatedly performed in the compression chambers continuously formed between the stationary wrap of the stationary scroll and the rotating wrap of the rotating scroll.

[0005] When the rotating scroll rotates relative to the fixed scroll, rotation of the rotating scroll must be prevented. To this end, a rotation-prevention member is provided between the rotating scroll and the main frame of the compressor positioned opposite it, thereby preventing the rotation of the rotating scroll.

[0006] Generally, Oldham rings or pin and ring are primarily known as anti-rotation components. Oldham rings are advantageous over pin and ring in terms of ease of assembly.

[0007] However, in the case of scroll compressors, wear occurs on the contact surfaces of the stationary scroll, the spinning scroll, and the Oldham ring due to the continuous rotational motion of the spinning scroll. Since this wear reduces the efficiency of the compressor, diagnosis is necessary.

[0008] Many conventional technologies for diagnosing compressors are known.

[0009] For example, Korean Patent Publication No. 10-2001-0081670 discloses a technology for evaluating the balance and stability of a compressor based on the displacement of a rotating body during operation detected by a displacement sensor mounted inside the compressor casing.

[0010] As another example, Public Patent No. 10-2019-0031667 discloses a technology for diagnosing a compressor failure using an ultrasonic signal or an acoustic detection signal collected through a sensor attached to the outer surface of the compressor.

[0011] As another example, Korean Patent Publication No. 10-2023-0146705 discloses a technology for measuring the position between a main frame and a rotating scroll and determining whether an abnormality occurs in the position measurement.

[0012] However, prior art and conventional methods have not disclosed a technique for specifically diagnosing contact surface wear of a compressor's fixed scroll, slewing scroll, Oldham ring, etc.

[0013] The present invention aims to provide an apparatus and method for diagnosing wear on the contact surface inside a compressor.

[0014] The present invention aims to provide an apparatus and method for diagnosing wear on a contact surface by utilizing vibrations caused by contact between some components inside a compressor.

[0015] The present invention aims to provide a device and method for diagnosing the internal condition of a compressor by attaching a sensor to the outside of the compressor.

[0016] In the diagnostic device and diagnostic method for a compressor according to an embodiment of the present invention, a sensor part attached to the outer surface of the body shell of the compressor can detect vibrations generated according to the operation of the compressor and output a vibration detection signal based on the vibration detection.

[0017] When the compressor operates, vibrations generated in the internal parts of the compressor, such as the compression section including the fixed scroll and the slewing scroll and / or the Oldham ring, are transmitted to the body shell.

[0018] At this time, the sensor unit detects vibrations transmitted to the body shell in real time and outputs a vibration detection signal. The sensor unit is preferably attached to the outer surface of the body shell at a location close to the compression unit or the Oldham ring. Preferably, it is attached at the location closest to the compression unit or the Oldham ring.

[0019] The signal detection unit can receive a vibration detection signal output from the sensor unit. The signal detection unit can amplify the received vibration detection signal if necessary.

[0020] The diagnostic unit can remove the signal excited by the rotational vibration component from the vibration detection signal received from the signal detection unit to extract the signal of the modal component of the body shell that prominently includes the signal excited by the collision vibration component, and analyze the extracted signal of the modal component of the body shell to diagnose whether the internal parts of the compressor are worn.

[0021] The diagnostic unit includes a signal receiving unit that receives a vibration detection signal transmitted from a signal detection unit, a signal processing unit that distinguishes a signal of a modal component of the body shell, including a signal excited by a rotational vibration component and a signal excited by a collision vibration component, from the vibration detection signal transmitted from the signal receiving unit, a filtering unit that filters and extracts only the signal of the modal component of the body shell, and a wear diagnostic unit that diagnoses whether the internal parts of the compressor are worn using the filtered signal of the modal component of the body shell.

[0022] The signal receiving unit can remove noise caused by electromagnetic interference included in the received vibration detection signal and then transmit the noise-removed vibration detection signal to the signal processing unit. By doing so, the signal processing unit can improve the accuracy of signal processing.

[0023] The vibration detection signal transmitted from the signal receiving unit to the signal processing unit is a vibration detection signal in the time domain. The signal processing unit converts the vibration detection signal in the time domain into a signal in the frequency domain (frequency signal) by performing an FFT transformation. In addition, to distinguish between the signal excited by the rotational vibration component and the signal excited by the collision vibration component, which are modal components of the body shell, the converted frequency signal is converted into a Quefrency signal by performing a Cepstrum transformation. From the converted Quefrency signal, the signal excited by the rotational vibration component and the signal of the modal component of the body shell are distinguished.

[0024] The wear diagnosis unit diagnoses wear on internal compressor components based on the ratio of high-frequency signals to low-frequency signals in the modal component signals of the body shell. At this time, if the ratio exceeds a preset threshold, it is diagnosed that wear has occurred on the internal compressor components. Preferably, the diagnosis unit diagnoses whether the fixed scroll, slewing scroll, and / or Oldham ring provided inside the compressor are worn.

[0025] The diagnostic device and diagnostic method of a compressor according to an embodiment of the present invention have one or more of the following effects.

[0026] According to the present invention, the internal condition of the compressor can be diagnosed without disassembling or taking apart the compressor.

[0027] According to the present invention, wear of the fixed scroll, slewing scroll, and Oldham ring inside the compressor can be diagnosed.

[0028] According to the present invention, since the characteristics of the compressor's compression section and Oldham ring are not affected by pressure, temperature, rotational speed, etc., usability is high.

[0029] According to the present invention, a sensor is attached to the outer surface of the compressor case to accurately diagnose the internal condition of the compression unit, and it has high applicability even after mass production.

[0030] According to the present invention, the wear of the compression part can be accurately checked by utilizing vibrations resulting from contact with the compression part of the compressor.

[0031] FIG. 1 is a configuration diagram of a compressor diagnostic device according to an embodiment of the present invention.

[0032] FIG. 2 is a cross-sectional view of a compressor according to an embodiment of the present invention.

[0033] FIG. 3 is a cross-sectional view of a compression section constituting a compressor according to an embodiment of the present invention.

[0034] FIG. 4 is an exploded perspective view showing the structure of the compression section, main frame, pressure seal, and Oldham ring constituting a compressor according to an embodiment of the present invention.

[0035] FIG. 5 is a perspective view of FIG. 4 shown from a different angle.

[0036] FIG. 6a is a schematic example of a compression section in a normal state in a compressor according to an embodiment of the present invention.

[0037] FIG. 6b is a schematic example of a compression section in a worn state in a compressor according to an embodiment of the present invention.

[0038] FIG. 7a is a schematic example of an Oldham ring in a steady state in a compressor according to an embodiment of the present invention.

[0039] FIG. 7b is a schematic example of an Oldham ring in a worn state in a compressor according to an embodiment of the present invention.

[0040] FIG. 8a is an example of a vibration detection signal in the time domain of a sensor unit according to an embodiment of the present invention.

[0041] FIG. 8b is an example of converting the vibration detection signal of FIG. 8a into a frequency signal.

[0042] FIG. 9 is a block diagram of a diagnostic unit constituting a compressor diagnostic device according to an embodiment of the present invention.

[0043] FIG. 10 is a flowchart illustrating a compressor diagnosis method according to an embodiment of the present invention.

[0044] FIG. 11 is an example diagram of a frequency signal according to vibration generated in a compressor according to an embodiment of the present invention.

[0045] Hereinafter, some embodiments of the present invention will be described in detail with reference to the exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the embodiments of the present invention, if it is determined that a detailed description of related known components or functions would hinder understanding of the embodiments of the present invention, such detailed description is omitted.

[0046] FIG. 1 is a configuration diagram of a compressor diagnostic device according to an embodiment of the present invention.

[0047] Referring to FIG. 1, a compressor diagnostic device according to an embodiment of the present invention may be configured to include a sensor unit (200) attached to the outer surface of a compressor (100), a signal detection unit (300) that receives a signal output from the sensor unit (200), and a diagnostic unit (400) that diagnoses the compressor (100) by analyzing the signal output from the signal detection unit (300).

[0048] The compressor (100) can compress a fluid, such as a refrigerant, to a high temperature and high pressure or convert it into a high-pressure gas and supply the refrigerant in a gaseous state to an air conditioner or an outdoor heat exchanger. The compressor (100) will be described in detail later with reference to the attached drawings.

[0049] The sensor unit (200) can be attached to the outer surface of the compressor (100) and can detect vibrations generated in the compressor (100).

[0050] The sensor unit (200) may include a vibration sensor. The vibration sensor can detect vibrations generated in the compressor (100) in real time and output a vibration detection signal based on the vibration detection. The vibration sensor may include a displacement sensor, an acceleration sensor, a velocity sensor, etc.

[0051] The signal detection unit (300) receives a vibration detection signal output from the sensor unit (200) and can perform signal processing such as amplifying the vibration detection signal. The signal detection unit (300) can transmit the signal-processed vibration detection signal to the diagnosis unit (400).

[0052] The diagnostic unit (400) can diagnose the compressor (100) by analyzing the vibration detection signal received in real time from the signal detection unit (300). Preferably, it can diagnose whether the compression part inside the compressor (100) is worn.

[0053] Specifically, the diagnostic unit (400) removes the vibration component caused by the rotation of the compressor (100) from the vibration detection signal received from the signal detection unit (300) so that only the vibration component caused by the collision remains, and can diagnose whether the compression part of the compressor (100) is worn by using the ratio of the high-frequency mode to the low-frequency mode in the frequency signal of the vibration component caused by the collision.

[0054] The diagnostic unit (400) can display the diagnosis result of whether there is wear on the display.

[0055] FIG. 2 is a cross-sectional view of a compressor according to an embodiment of the present invention, FIG. 3 is a cross-sectional view of a compression unit constituting a compressor according to an embodiment of the present invention, FIG. 4 is an exploded perspective view showing the structure of a compression unit, a main frame, a pressure seal, and an Oldham ring constituting a compressor according to an embodiment of the present invention, and FIG. 5 is a perspective view of FIG. 4 shown from a different angle.

[0056] The compressor (100) according to the present invention may be configured to include a case (10), a motor unit (20), a rotating shaft (30), a main frame (40), and a compression unit (C).

[0057] The fixed scroll (60) (or non-rotating scroll) and the rotating scroll (70) constituting the compression section (C) can be stacked on the main frame (40).

[0058] Below, we will describe a compressor as an example in which a compression unit (C) is positioned on the upper part of the main frame (40) and an electric motor unit (20) is positioned on the lower part of the main frame (40).

[0059] The case (10) can form the exterior of the compressor (100). The case (10) can be made of a cylindrical body shell (11) that is open at the top and bottom.

[0060] A sensor part (200) may be attached to the outer surface of the body shell (11). The sensor part (200) may be attached, for example, by an adhesive, a fixing means, etc. Alternatively, it may be attached to a mount fixed to the outer surface of the compressor (100), or the sensor part (200) may be attached by wrapping the body shell (11) with an elastic band or Velcro.

[0061] The sensor part (200) may be attached to the outer surface of the body shell (11) at a location close to the compression part (C) or the Oldham ring (80) to be described later. Preferably, it is attached as close as possible to the compression part (C) or the Oldham ring (80), and more preferably, it is attached at the closest location.

[0062] The sensor unit (200) can detect vibrations generated in the compressor (100) in real time and output a vibration detection signal. The vibration is a vibration that occurs as the compressor (100) operates, and vibrations generated from each internal component can be transmitted to the body shell (11). The sensor unit (200) detects the vibrations transmitted to the body shell (11) in this manner.

[0063] The body shell (11) is supported on the floor and does not generate energy on its own. If the vibration generated inside the body shell (11) is considered as the source of excitation, the body shell (11) can be considered as a vibrating body that is excited by the generated energy.

[0064] When the body shell (11) is placed as a vibrating body, the vibration generated inside the body shell (11) can be an excitation source. The excitation source generated inside the body shell (11) can be divided into excitation caused by the rotation of the rotation axis and the compression part (C) and excitation caused by contact between parts during rotation.

[0065] The upper part open in the body shell (11) of the case (10) can be closed with the upper shell (13). The part open downward in the body shell (11) can be closed with the lower shell (17).

[0066] The interior of the case (10) can form a suction space (S1). The suction space (S1) can be viewed as a refrigerant inlet space into which refrigerant is introduced. This refrigerant can be introduced into the suction space (S1) through a refrigerant suction pipe (12) located in the body shell (11).

[0067] The electric motor (20) and the compression unit (C) can be placed in the suction space (S1). The suction space (S1) can also be called an electric motor room.

[0068] A discharge space (S2) in which refrigerant compressed by a compression unit (C) is discharged may be provided at the top of the case (10) covered by the upper shell (13). A discharge pipe (14) connected to the discharge space (S2) to discharge the refrigerant to the outside may be connected to the upper shell (13).

[0069] The discharge pipe (14) can be connected to a pipe (not shown) that delivers refrigerant to a condenser (not shown) of a refrigeration cycle. A high-low pressure separator (15) may be provided inside the case (10). The high-low pressure separator (15) can separate the suction space (S1), which is a relatively low pressure section, from the discharge space (S2), which is a relatively high pressure section.

[0070] The suction space (S1) corresponds to the lower space of the high-low pressure separator (15), and the discharge space (S2) corresponds to the upper space of the high-low pressure separator (15). An electric motor (20) may be placed in the suction space (S1). The electric motor (20) generates rotational force and can rotate the rotation shaft (30).

[0071] In this embodiment, the electric motor (20) may be positioned relatively lower than the compression unit (C), or the compression unit (C) may be positioned below the electric motor (20). The electric motor (20) may be largely composed of a rotor (23) and a stator (21, 25).

[0072] A balance weight (27) is coupled to the rotor (23) so that the rotor (23) can rotate stably even if the rotation axis (30) has an eccentric portion. The stator (21, 25) may include a stator core (21) and a stator coil (25).

[0073] The stator core (21) is formed in a cylindrical shape and can be fixed to the inner surface of the body shell (11) by hot press fitting. The stator coil (25) is wound on the stator core (21) and can be electrically connected to an external power source through a terminal device (T) that is coupled through the body shell (11).

[0074] The lower end of the rotation shaft (30) can be rotatably supported by a lower bearing (19) installed at the bottom of the case (10). The lower bearing (19) is supported by a lower frame (18) fixed to the inner surface of the case (10), thereby stably supporting the rotation shaft (30).

[0075] The lower frame (18) can be fixed to the inner wall surface of the case (10) by welding, and the bottom surface of the case (10) can be used as an oil storage space. The oil stored in the oil storage space is transferred upward through oil pipes (34, 35) provided on the rotating shaft (30), and the transferred oil can enter the compression chambers (V1, V2) of the electric motor (20) and the compression unit (C) to perform lubrication.

[0076] The upper part of the rotation axis (30) can be rotatably supported by the main frame (40). The main frame (40) can be fixedly installed on the inner wall surface of the case (10), like the lower frame (18).

[0077] A bearing portion (42) protruding downward may be provided on the bottom surface of the main frame (40), and the upper portion of the rotating shaft (30) may be fitted into the inside of the bearing portion (42).

[0078] A slide bushing (37) may be attached to the upper part of the rotation shaft (30). The slide bushing (37) may be positioned between the upper part of the rotation shaft (30) and the rotation shaft coupling part (73) provided on the rotation plate part (71) of the rotation scroll (70).

[0079] An eccentric projection (38) provided at the upper end of the rotation axis (30) can be fitted into the slide bushing (37). The eccentric projection (38) can rotate the rotation scroll (70).

[0080] The main frame (40) can be fixed to the inner wall surface of the case (10) like the lower frame (18). A frame body (41) may be provided at the center of the main frame (40). A bearing part (42) may be provided inside the frame body (41) so that the upper part of the rotation shaft (30) can be connected thereto.

[0081] A flange portion (43) may be provided on the frame body (41). The flange portion (43) may extend radially from the frame body (41). A scroll fixing portion (44) may be provided on the flange portion (43). The scroll fixing portion (44) may support the fixed scroll (60) in the axial and radial directions. Multiple such scroll fixing portions (44) may be provided along the circumferential direction.

[0082] A flange hole (44a) may be formed in the scroll fixing part (44). The flange hole (44a) is connected to the scroll hole (67) of the fixed scroll (60), so that a guide (not shown), which is a type of fastener, can pass through them continuously. The fixed scroll (60) can be assembled to the flange part (43) by means of the guide.

[0083] A pivot space (42a) may be formed on the upper part of the frame body (41) corresponding to between the multiple flange portions (43). The pivot space (42a) may be connected to a bearing portion (42).

[0084] The pivot space (42a) is positioned above the bearing portion (42) and may have a larger diameter than the bearing portion (42). The pivot space (42a) may accommodate the rotational axis coupling portion (73) of the pivot scroll (70). Since the inner diameter of the pivot space (42a) is larger than the outer diameter of the rotational axis coupling portion (73), the rotational axis coupling portion (73) may be pivotable in the pivot space (42a).

[0085] A scroll support surface (SF) may be provided on the outer edge of the rotation space (42a). This scroll support surface (SF) can support the rotation scroll (70) in the axial direction. Between the scroll support surface (SF) and the flange portions (43), a member receiving portion (47) in which an Oldham ring (80) is received may be provided. The Oldham ring (80) acts as a rotation prevention member and prevents the rotation of the rotation scroll (70). The Oldham ring (80) can perform linear reciprocating motion inside the member receiving portion (47).

[0086] A seal mounting portion (45) may be provided on the scroll support surface (SF). The seal mounting portion (45) may be formed in a shape where a part of the scroll support surface (SF) is recessed. A pressure seal (50) may be housed in the seal mounting portion (45).

[0087] The seal mounting portion (45) may, for example, have a shape corresponding to the shape of the pressure seal (50). Alternatively, as another example, a pressure seal (50) made of a flexible material may be deformed to fit the shape of the seal mounting portion (45) and fitted into the seal mounting portion (45).

[0088] The seal mounting portion (45) may include a first mounting portion (45a) and a second mounting portion (45b) having different sizes. A first pressure seal (51), to be described later, may be housed in the first mounting portion (45a). A second pressure seal (55), to be described later, may be housed in the second mounting portion (45b).

[0089] In this embodiment, the first mounting part (45a) may have a relatively smaller size than the second mounting part (45b). Accordingly, the first mounting part (45a) may be positioned closer to the center of the main frame (40), that is, the center of the rotation axis (30), than the second mounting part (45b).

[0090] The first mounting part (45a) and the second mounting part (45b) may be spaced apart from each other. A portion of the refrigerant from the compression chambers (V1, V2) may be transferred to the scroll support surface (SF) corresponding to the space between the first mounting part (45a) and the second mounting part (45b).

[0091] The scroll support surface (SF) may constitute part of the intermediate pressure chamber. The refrigerant delivered to the scroll support surface (SF) can float the first pressure seal (51) and the second pressure seal (55) respectively placed in the first mounting portion (45a) and the second mounting portion (45b). Here, float means moving the rotating scroll (70) axially together with the first pressure seal (51) and the second pressure seal (55). The intermediate pressure chamber may also be referred to as a back pressure chamber.

[0092] A pressure seal (50) may be placed in the seal mounting portion (45). This pressure seal (50) can lift the rotating scroll (70) in the direction of the fixed scroll (60). Accordingly, leakage of refrigerant in the compression chambers (V1, V2) can be prevented.

[0093] Specifically, when the refrigerant in the intermediate pressure state of the compression chambers (V1, V2) is discharged into the intermediate pressure chamber through the communication hole (72) of the rotating scroll (70), the refrigerant can pressurize the pressure seal (50) located inside the chamber. The pressure seal (50), which was seated on the seal mounting part (45), can rise in the direction of the rotating scroll (70) while being pressurized. The pressure seal (50) can block the leakage of the refrigerant and at the same time, lift the rotating scroll (70) in the direction of the fixed scroll (60).

[0094] When the rotating scroll (70) rises, the end of the rotating scroll (70) may come into close contact with the fixed scroll (60). Accordingly, leakage of refrigerant from the compression chambers (V1, V2) can be prevented, and the reliability of the compressor can be improved. Specifically, the rotating scroll (70) tends to spread axially relative to the fixed scroll (60) due to the pressure of the compression chambers (V1, V2).

[0095] However, the pressure seal (50) can form an intermediate pressure chamber together with the rotating scroll (70) and the main frame (40) to push the rotating scroll (70) in the direction of the fixed scroll (60). Accordingly, the rotating scroll (70) and the fixed scroll (60) are prevented from separating from each other, thereby preventing the refrigerant compressed in the compression chambers (V1, V2) from leaking in the axial direction.

[0096] In this embodiment, the pressure seal (50) may include a first pressure seal (51) and a second pressure seal (55). The first pressure seal (51) and the second pressure seal (55) may be spaced apart from each other, so that an intermediate pressure chamber may be formed between them.

[0097] The first pressure seal (51) has a smaller diameter than the second pressure seal (55) and can be positioned closer to the center of the rotation axis (30). The first pressure seal (51) and the second pressure seal (55) can each have a roughly circular structure. The first pressure seal (51) can block one side of the intermediate pressure chamber.

[0098] The refrigerant introduced into the intermediate pressure chamber may be blocked by the first pressure seal (51) and may not pass in the direction of the rotation axis (30).

[0099] The second pressure seal (55) may be provided concentrically with the first pressure seal (51) while surrounding the first pressure seal (51). The second pressure seal (55) may block the opposite side of the intermediate pressure chamber. The refrigerant introduced into the intermediate pressure chamber may be blocked by the second pressure seal (55) and may not flow out.

[0100] Looking at the compression section (C), the compression section (C) can compress the refrigerant while rotating by the rotation axis (30) in the internal space (S1) of the case (10). In this embodiment, the compression section (C) includes two relative rotating parts, namely a fixed scroll (60) and a rotating scroll (70). At this time, it is preferable that the sensor section (200) be attached to the outer surface of the body shell (11) as close as possible to the fixed scroll (60) and the rotating scroll (70).

[0101] The rotating scroll (70) can rotate in engagement with the eccentric protrusion (38) protruding from the upper part of the rotation axis (30) and vary the volume of the compression chambers (V1, V2) located between it and the fixed scroll (60), and in this process, the refrigerant in the compression chambers (V1, V2) can be compressed and discharged.

[0102] Looking at the back pressure chamber assembly (16) placed in the compression section (C), the back pressure chamber assembly (16) can be placed on the upper side of the fixed scroll (60). Accordingly, the fixed scroll (60) can be pressed in the direction toward the rotating scroll (70) by the back pressure of the back pressure chamber (not shown) to seal the compression chambers (V1, V2).

[0103] Here, back pressure refers to the force acting on the back pressure chamber. Although not illustrated, the back pressure chamber assembly (16) may include a back pressure plate coupled to the upper surface of the fixed scroll (60) and a floating plate slidably coupled to the back pressure plate to form a back pressure chamber together with the back pressure plate. Alternatively, as another example, the back pressure chamber assembly (16) may be omitted, and a gasket of a simple structure may be placed on the upper part of the fixed scroll (60).

[0104] A pivot scroll (70) and a fixed scroll (60) may be disposed at the lower part of the back pressure assembly (16). The fixed scroll (60) may be disposed at the upper part of the pivot scroll (70). The fixed scroll (60) may be fixedly coupled to the main frame (40) or may be coupled so as to be movable in the up and down direction.

[0105] The fixed scroll (60) may be coupled to the main frame (40) so as to be movable in the axial direction. The fixed scroll (60) may include a fixed plate portion (61) formed in the shape of a disc on the upper side.

[0106] The fixed scroll (60) may include a fixed wrap (64) protruding downward from the fixed plate portion (61). The fixed wrap (64) may be made spirally to engage with the pivot wrap (74) of the pivot scroll (70) described below. The first compression chamber (V1) is formed by the pivot wrap (74).

[0107] The side wall of the fixed scroll (60) may be provided with an inlet (not shown) through which refrigerant present inside the suction space (S1) is sucked in.

[0108] A discharge port (63a) may be formed in the approximately central part of the fixed end plate (61) to allow compressed refrigerant to be discharged from the discharge pressure chamber (not labeled) toward the discharge space (S2).

[0109] The discharge port (63a) may be formed at a location where the discharge pressure chamber (not labeled) of the first compression chamber (V1) and the discharge pressure chamber (not labeled) of the second compression chamber (V2), which will be described later, are in communication with each other. A discharge guide groove (62) may be provided in a recessed form around the discharge port (63a).

[0110] A bypass hole (63c) may be provided in the fixed end plate portion (61). This bypass hole (63c) may penetrate the fixed end plate portion (61) axially between the suction port and the discharge port (63a), that is, in the intermediate pressure chamber (not shown), and communicate with the intermediate discharge port (not shown) to be described later. Accordingly, a portion of the refrigerant compressed in the compression chambers (V1, V2) can be bypassed to the discharge space (S1), thereby suppressing over-compression of the refrigerant in each compression chamber (V1, V2). Reference numeral 63b indicates a valve buffer groove.

[0111] A plurality of guide blocks (65) may be provided along the circumferential direction on the outer surface of the fixed plate portion (61). Guide grooves (66) may be provided in the guide blocks (65). The guide grooves (66) may extend in the radial direction of the fixed scroll (60). A guide projection (83) provided in the Oldham ring (80) may be inserted into the guide grooves (66).

[0112] The guide protrusion (83) can slide inside the guide groove (66). As the guide protrusion (83) is guided into the guide groove (66), the Oldham ring (80) can perform a linear reciprocating motion.

[0113] Looking at the rotating scroll (70), the rotating scroll (70) may include a rotating plate portion (71) having a roughly circular shape and a spiral rotating wrap (74) protruding from the rotating plate portion (71) toward the fixed plate portion (61).

[0114] A second compression chamber (V2) may be provided inside the swivel wrap (74). The second compression chamber (V2) may form a single compression chamber (V1, V2) connected together with the first compression chamber (V1) of the fixed wrap (64).

[0115] The pivot plate portion (71) of the pivot scroll (70) can be pivotally driven while supported on the upper surface of the main frame (40). An Oldham ring (80) is installed between the pivot plate portion (71) and the main frame (40) to prevent rotation of the pivot scroll (70).

[0116] On the lower surface of the rotating plate portion (71) of the rotating scroll (70), a rotational shaft coupling portion (73) into which an eccentric projection (38) of the rotational shaft (30) is inserted may protrude in a roughly ring shape. Through the rotational shaft coupling portion (73), the rotational force of the rotational shaft (30) can cause the rotating scroll (70) to rotate.

[0117] Drawing symbol 73a indicates a coupling groove provided inside the rotation shaft coupling part (73).

[0118] A keyway (75) may be provided in the pivot plate portion (71). The keyway (75) may be recessed from the bottom surface of the pivot plate portion (71). Two keyways (75) may be provided with a phase difference of 180° in the circumferential direction so as to correspond to the key protrusion (85) of the Oldham ring (80). The two keyways (75) may be provided so as to be located on a virtual line passing through the center of the pivot plate portion (71).

[0119] The rotational movement of the rotary scroll (70) can be prevented by inserting the key protrusion (85) of the Oldham ring (80) into the keyway (75). The Oldham ring (80) is guided by the main frame (40) and moves in a straight reciprocating motion while simultaneously being linked with the rotary scroll (70). In this process, rotation of the rotary scroll (70) is prevented.

[0120] The keyway (75) can be formed on the outer surface of the pivot plate portion (71) in the direction of the center of the pivot plate portion (71). That is, the keyway (75) can be formed radially toward the axis of rotation.

[0121] The keyway (75) is formed as a rectangular shape extending radially, and the radial length of the keyway (75) may be formed longer than the radial length of the key protrusion (85) so that the key protrusion (85) can slide radially. A portion of the keyway (75) may be provided spaced apart from the scroll support surface (SF) in the axial direction of the rotation axis (30).

[0122] FIG. 6a is a schematic example of a compression section in a normal state in a compressor according to an embodiment of the present invention, and FIG. 6b is a schematic example of a compression section in a worn state in a compressor according to an embodiment of the present invention.

[0123] As shown in Fig. 6a, when the fixed scroll (60) and the rotating scroll (70) constituting the compression section (C) are in a normal state, their surfaces come into contact with each other during the operation of the compressor (100).

[0124] However, if the compressor (100) operates for a long period of time, wear may occur on the contact surface between the fixed scroll (60) and the rotating scroll (70) due to the continuous rotational and pivoting motion of the compression part (C).

[0125] As shown in Fig. 6b, if wear occurs on the fixed scroll (60) and the rotating scroll (70), the rotation axis of the rotating scroll (70) may become misaligned during the operation of the compressor (100), and a collision may occur at the corners between the fixed scroll (60) and the rotating scroll (70) rather than surface contact.

[0126] Such collisions caused by wear can similarly occur in Oldham rings (80).

[0127] FIG. 7a is a schematic example of an Oldham ring in a normal state in a compressor according to an embodiment of the present invention, and FIG. 7b is a schematic example of an Oldham ring in a worn state in a compressor according to an embodiment of the present invention.

[0128] The key protrusion (85) of the Oldham ring (80) allows the pivot scroll (70) to be inserted into the key groove (75), and as shown in FIG. 7a, when the key protrusion (85) of the Oldham ring (80) and the key groove (75) of the pivot scroll (70) are in a normal state without wear, their surfaces come into contact with each other during the operation of the compressor (100).

[0129] However, if the compressor (100) is operated for a long period of time, wear may occur on the key protrusion (85) and the keyway (75).

[0130] As shown in Fig. 7b, if wear occurs between the key protrusion (85) of the Oldham ring (80) and the keyway (75) of the rotating scroll (70), collision may occur at the corners rather than surface contact between the key protrusion (85) and the keyway (75) during the operation of the compressor (100).

[0131] In this way, collisions in the compression section (C) (hereinafter referred to as "compression section collisions") and collisions in the Oldham ring (80) (hereinafter referred to as "Oldham ring collisions") can cause vibrations in the compressor (100).

[0132] A sensor part (200) attached to the outer surface of the body shell (11) of the compressor (100) detects vibrations caused in the compressor (100).

[0133] The vibration detection signal detected by the sensor unit (200) includes signals for all vibrations generated in the compressor (100). These may include, for example, a vibration component generated by the rotation of the rotating shaft (30) (hereinafter referred to as the 'rotational vibration component'), a vibration component generated by the collision of the compression unit (hereinafter referred to as the 'compression unit vibration component'), and a vibration component generated by the collision of the Oldham ring (hereinafter referred to as the 'Oldham ring vibration component').

[0134] Since the above-mentioned compression section vibration component and Oldham ring vibration component are vibration components generated by the collision of the compression section and the collision of the Oldham ring, they may be collectively referred to as 'collision vibration components' as necessary below.

[0135] In this way, if the body shell (11) of the compressor (100) is placed as a vibrating body, the vibration generated inside the body shell (11) can become an excitation source. Therefore, the vibration detection signal according to the excitation source can be broadly divided into a rotational vibration component and a collision vibration component.

[0136] Of course, the above vibration detection signal may include vibration components caused by other causes in addition to the rotational vibration component and collision vibration component, but in the case of the compressor (100), the magnitude is negligible compared to the two components, so it can be ignored.

[0137] FIG. 8a is an example of a vibration detection signal in the time domain detected by a sensor unit according to an embodiment of the present invention, and FIG. 8b is an example of the vibration detection signal of FIG. 8a converted into a frequency signal.

[0138] Referring to FIG. 8a, the time taken for a vibration detection signal due to collision is relatively shorter compared to a vibration detection signal due to surface contact. In other words, collision occurs relatively quickly compared to surface contact. This is because if no wear occurs on the compression part (C) and the Oldham ring (80), the surface contact is maintained continuously, and if wear occurs on the compression part (C) and the Oldham ring (80), the contact surface becomes smaller, causing collision to occur within a short period of time.

[0139] Referring to Fig. 8b, when vibration detection signals caused by surface contact and collision are converted into frequency signals, the frequency signal caused by surface contact has energy concentrated in a relatively low and narrow frequency band, while conversely, the frequency signal caused by collision can generate energy in a relatively high and wide frequency band.

[0140] FIG. 9 is a block diagram of the configuration of a diagnostic unit constituting a compressor diagnostic device according to an embodiment of the present invention.

[0141] Referring to FIG. 9, the diagnostic unit (300) according to an embodiment of the present invention may be configured to include a signal receiving unit (201), a signal processing unit (202), a filtering unit (203), and a wear diagnostic unit (204).

[0142] The signal receiving unit (201) can receive a vibration detection signal transmitted in real time from the signal detection unit (200) and transmit the vibration detection signal to the signal processing unit (202) to be described later.

[0143] The signal receiving unit (201) may optionally remove noise caused by electromagnetic interference included in the received vibration detection signal. In this case, the noise-removed vibration detection signal may be transmitted to the signal processing unit (202).

[0144] The signal processing unit (202) can perform signal processing on the vibration detection signal received in real time according to a set process. That is, the signal processing unit (202) can distinguish and separate the signal of the rotational vibration component and the signal of the collision vibration component from the vibration detection signal.

[0145] The filtering unit (203) can filter and extract only the modal component signal of the shell in which the excitation caused by the collision vibration component is mainly reflected.

[0146] The wear diagnosis unit (204) can diagnose whether there is wear inside the compressor (100) based on the modal component of the filtered shell. Specifically, the wear diagnosis unit (204) can diagnose wear of the fixed scroll (60) and the rotating scroll (70) and / or the Oldham ring (80) based on the ratio of the high-frequency signal to the low-frequency signal in the signal of the modal component of the filtered shell.

[0147] FIG. 10 is a flowchart illustrating a compressor diagnosis method according to an embodiment of the present invention.

[0148] Referring to FIG. 10, in the compressor diagnostic method according to an embodiment of the present invention, a sensor part (200) attached to the outer surface of the body shell (11) of the compressor (100) detects vibration transmitted to the body shell (11) and outputs a vibration detection signal.

[0149] As the compressor (100) operates, vibrations occur inside, and these vibrations can all be transmitted to the body shell (11) in real time.

[0150] The sensor unit (200) attached to the body shell (11) can output a vibration detection signal in the time domain in real time for all vibrations transmitted to the body shell (11) (S101).

[0151] When the body shell (11) is placed as a vibrating body, the vibration generated inside the body shell (11) can be an excitation source. The excitation source can be broadly divided into vibration caused by rotational and pivoting motion of the compression part (C) and vibration caused by collision at the contact part of the compression part (C) and / or Oldham ring (80) during rotational and pivoting motion. Accordingly, the vibration detection signal of the sensor part (200) can be broadly divided into a signal excited by a rotational vibration component and a signal excited by a collision vibration component.

[0152] If x(t) is the time-domain vibration detection signal obtained from the sensor unit (200), x(t) can be represented as the convolution of the excitation characteristic of the body shell (11) and the system characteristic, and can be expressed as the formula x(t) = g(t) × h(t). Here, g(t) is the excitation characteristic and h(t) is the system characteristic.

[0153] The vibration detection signal in the time domain is converted into a signal in the frequency domain (S102). At this time, the converted signal in the frequency domain can be referred to as a 'frequency signal'.

[0154] If the Fast Fourier Transform (FFT) is applied to x(t) to convert a vibration detection signal in the time domain into a frequency signal, F(x(t))=X(ω)=A x (ω)exp(jφ x It can be represented as ), and when the time domain signal is converted into a frequency signal, it can be divided into magnitude A(ω) and phase exp(jφ) depending on the frequency.

[0155] In other words, since the FFT was applied to x(t)=g(t)×h(t), the FFT of the convolution can be expressed as a product in the frequency domain as X(ω)=G(ω)H(ω).

[0156] When expressed in terms of magnitude and phase, as in electrons, the magnitude Ax(ω) according to frequency can be represented as shown in FIG. 11. FIG. 11 is an example diagram of a frequency signal according to the vibration of a compressor according to an embodiment of the present invention. A is the frequency signal for all vibrations.

[0157] These frequency signals may include a signal excited by a collision vibration component (B) and a signal excited by a rotational vibration component (C). Both components are transmitted to the body shell (11), and the rotational vibration component, which is an integer multiple of the rotational frequency, is the main component of the body shell (11). This rotational vibration component may appear as a harmonic component.

[0158] The rotational vibration component is an unconstrained large displacement vibration, and has much greater energy compared to a constrained vibration system. Accordingly, when vibration is transmitted to the body shell (11), the rotational frequency appears significantly across the entire frequency range even if it does not match the mode frequency, which is a system characteristic of the body shell (11), so the signal excited by the collision vibration component and the signal excited by the rotational vibration component can be combined.

[0159] In this case, it is difficult to accurately extract the magnitude of the collision vibration component. Therefore, signal processing is required to remove the signal excited by the rotational vibration component constituting the rotational harmonics signal from the frequency signal and to leave only the modal component of the body shell (11) where the signal excited by the collision vibration component is prominent.

[0160] Of course, as explained above, the frequency signal may contain other components in addition to the two components (B, C), but since their magnitude is relatively small compared to the two components (B, C), they can be ignored.

[0161] Accordingly, a cepstrum transform is performed to separate the rotational vibration component and the collision vibration component from the frequency signal (S103). Specifically, first, only the magnitude Ax(ω) is taken from the frequency signal. This means that all phase values ​​are set to zero, as if the frequency signal were viewed again in the time domain.

[0162] A x Applying the logarithm and inverse FFT to (ω) gives C(τ)=F -1 [Log(A x It can be expressed as (ω))], and the transformed C(τ) becomes the Cepstrum value.

[0163] Here, if we examine using the expression X(ω)=G(ω)H(ω), when considering only the magnitude, A x (ω)=A g (ω)A h Since it is (ω), taking the logarithm gives Log(A x (ω))=Log(A g (ω))+Log(A h As shown in (ω), the system characteristics and the excitation components can be separated into a sum. By taking the logarithm in this way, significantly better performance can be obtained compared to simply applying the IFFT.

[0164] In this case, if we apply IFFT, F -1 [Log(A x (ω))]=F -1 [Log(A g (ω))]+F -1 [Log(A h It can be expressed as (ω))]. This implies that, unlike the conventional method used in Cepstrum where the phase is set to 0 and only the magnitude is IFFTed, it is not a concept of returning to the signal but rather treating the frequency domain as the time domain and performing the FFT one more time. In other words, performing the IFFT with the original normal phase value returns to the original x(t).

[0165] When the Cepstrum transform is performed, the frequency domain is converted into the Quefrency domain, which can be expressed in units of seconds, similar to time. Quefrency is a commonly used name derived by reversing the 'que' and 'fre' in Frequency; although the meaning differs, seconds are used as the unit because the IFFT was performed.

[0166] As shown in Figure 11, the collision vibration component and the rotational vibration component can be distinguished in the Quefrency region by the Cepstrum transformation.

[0167] Referring to FIG. 11, the rotational harmonics component, which is the main component of the signal excited by the rotational vibration component, appears repeatedly at a constant period according to the rotational operation of the compressor (100). The resulting components are collected at the rear on the cepstrum. For example, if there is a signal that appears once every 30 seconds in the time domain, this frequency can be 1 / 30 Hz. Similarly, if the operating speed of the compressor (100) is 30 Hz, the harmonics appear periodically at integer multiples of 30 Hz, so this component appears in the frequency domain with a value of 1 / 30 second.

[0168] On the other hand, the modal component of the body shell (11) appears only at a specific frequency and is not repetitive, so the repetition period is close to infinite Hz. This converges to a value approximately 0 seconds on the Cepstrum.

[0169] Here, filtering is performed to remove rotational harmonic components (S104), and rotational harmonic components are removed (S105), thereby extracting the modal components of the body shell (11) (S106). When using a low-pass filter during filtering, rotational harmonic components are removed, and only the modal components of the body shell (11), which are characterized by features excited by collision vibration components, can be extracted.

[0170] Afterwards, the collision vibration component from which the rotational vibration component has been removed is subjected to an FFT and Exp (exponentiation) in the reverse order of Quefrency to Cepstrum to return it to the frequency domain signal (S107). The result is a frequency signal containing only the collision vibration component, as shown in the bottom part of Fig. 11.

[0171] Next, the frequency signal of the modal component of the body shell (11) is used to diagnose wear of the compressor (100), specifically wear of the compression part (C) and / or Oldham ring (80) (S108).

[0172] When wear occurs on the fixed scroll (60) and the rotating scroll (70), which are the main components of the compression section (C), and on the Oldham ring (80), sharp contact rather than soft contact occurs at the contact surface. Accordingly, by analyzing the characteristics of the collision vibration component of the body shell (11), it is possible to determine how much collision caused by wear has occurred and to what extent the vibration caused by collision is.

[0173] In the normal state where there is no wear, the compression part (C) makes smooth contact with the contact surface during rotation, so the contact time is long, allowing high low-frequency energy to be transmitted to the body shell (11). However, if wear occurs, a gap may form on the contact surface due to the wear, causing localized collisions caused by shaking. In this case, the contact time is shortened due to the collision, so low-frequency energy lower than in the normal state and high-frequency energy higher can be transmitted to the body shell (11).

[0174] By using this, the degree of wear of the compressor (100) can be diagnosed by observing the change in the ratio of the vibration signal in the high-frequency band to the vibration signal in the low-frequency band.

[0175] That is, when comparing the frequency signal of the modal component of the body shell (11) from which rotational harmonics components have been removed, divided into normal state and wear state, if wear occurs, the contact part changes to impact, and the vibration corresponding to the low-frequency band component decreases, and the high-frequency band component increases.

[0176] Therefore, normal and worn conditions can be distinguished through the ratio of low-frequency band components to high-frequency band components. Since this considers only changes in the frequency components of the body shell (11), it can be used as a factor to determine whether wear occurs even if the shape of the compression part (C) or Oldham ring (80) changes or operating conditions such as pressure, temperature, and shaft rotation speed change.

[0177] In this embodiment, if the ratio of the high-frequency band to the low-frequency band in the frequency signal of the collision vibration component is greater than or equal to a preset reference value, it is diagnosed that wear has occurred in the compression part (C) and / or Oldham ring (80).

[0178] Conventional compressor diagnosis identifies and analyzes the characteristics caused by the failure itself; however, these characteristics require calculating the corresponding frequencies through complex physical assumptions and mathematical calculations, which must then be verified experimentally. Furthermore, if the diagnostic target changes or the configuration alters, the physical assumptions or boundary conditions must change, necessitating the derivation of new calculation methods.

[0179] On the other hand, the compressor diagnosis according to the present invention provides a method of diagnosing by analyzing the effect on the vibration of the body shell (11) supported on the floor by removing or maximally excluding rotational vibration components and replacing the collision caused by wear as the vibration source.

[0180] The vibration frequency of the body shell (11) can be easily obtained through experimentation or analysis even in complex systems, so it has high usability. In addition, since the sensor part is attached to the outer surface of the body shell (11), it can be easily attached to the compressor after mass production as well as during the development and mass production stages to diagnose wear.

[0181] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

Claims

1. A sensor unit attached to the body shell of the compressor to detect vibrations generated in the compressor; A signal detection unit that receives a vibration detection signal corresponding to vibration detection from the sensor unit above; A compressor diagnostic device comprising a diagnostic unit that removes a signal excited by a rotational vibration component from a vibration detection signal received from the above signal detection unit to extract a signal of a modal component of the body shell including a signal excited by a collision vibration component, and diagnoses whether a part of the compressor is worn based on the extracted signal of the modal component of the body shell.

2. In Claim 1, The above sensor part is a compressor diagnostic device attached to the outer surface of the body shell at a location close to the compression part or Oldham ring constituting the compressor.

3. In Claim 1, A compressor diagnostic device in which the signal detection unit receives a vibration detection signal output from the sensor unit in real time, amplifies the vibration detection signal, and then transmits it to the diagnostic unit in real time.

4. In Claim 1, The above diagnostic unit is, A signal receiving unit that receives a vibration detection signal transmitted from the above signal detection unit; A signal processing unit that distinguishes the signal of the modal component of the body shell, including the signal excited by the rotational vibration component and the signal excited by the collision vibration component, from the vibration detection signal transmitted from the signal receiving unit; A filtering unit that filters and extracts only the signal of the modal component of the above body shell; and A compressor diagnostic device comprising: a wear diagnostic unit that diagnoses whether the internal parts of the compressor are worn using the signal of the modal component of the filtered body shell.

5. In Claim 4, A compressor diagnostic device in which the signal receiving unit removes noise caused by electromagnetic interference included in the received vibration detection signal and then transmits the noise-removed vibration detection signal to the signal processing unit.

6. In Claim 4, The above signal processing unit is, A compressor diagnostic device that converts a time-domain vibration detection signal transmitted from the above signal receiving unit into a frequency signal, converts the frequency signal into a Quefrency signal by cepstrum conversion, and separates the converted Quefrency signal into a signal excited by the collision vibration component and a signal of the modal component of the body shell.

7. In Claim 4, The above wear diagnosis unit is a compressor diagnostic device that diagnoses wear of internal compressor parts based on the ratio of a high-frequency signal to a low-frequency signal in the signal of the modal component of the filtered body shell.

8. In Claim 7, The above-mentioned wear diagnosis unit is a compressor diagnosis device that diagnoses that wear has occurred in the internal parts of the compressor if the above-mentioned ratio is greater than or equal to a preset standard value.

9. In Claim 1, The above diagnostic unit is a compressor diagnostic device that diagnoses whether the fixed scroll and slewing scroll or Oldham ring constituting the compressor are worn.

10. Step in which the compressor operates; When the above compressor operates, a sensor unit attached to the body shell of the above compressor detects vibration generated in the compressor and outputs a vibration detection signal; A step of extracting a signal of a modal component of a body shell including a signal excited by a collision vibration component by removing a signal excited by a rotational vibration component from the above vibration detection signal; and A compressor diagnostic method comprising the step of diagnosing whether the internal parts of the compressor are worn by analyzing the signal of the modal component of the extracted body shell.

11. In Claim 10, The step of extracting the collision vibration component described above is, A step of receiving a vibration detection signal output from the sensor unit; A step of distinguishing the signal of the modal component of the body shell, including the signal excited by the rotational vibration component and the signal excited by the collision vibration component, in the above vibration detection signal; A compressor diagnostic method comprising the step of filtering and extracting only the signal of the modal component of the above body shell.

12. In Claim 11, The step of distinguishing between the signal excited by the rotational vibration component and the signal of the modal component of the body shell is, A step of converting the vibration detection signal in the time domain output from the sensor unit into a frequency signal; A step of converting the above frequency signal into a Quefrency signal by cepstrum transform; and A compressor diagnostic method comprising the step of distinguishing between the signal excited by the rotational vibration component and the signal of the modal component of the body shell in the converted Quefrency signal.

13. In Claim 11, A compressor diagnostic method for diagnosing whether the internal parts of the compressor are worn based on the ratio of the high-frequency signal to the low-frequency signal in the signal of the modal component of the filtered body shell.

14. In Claim 13, A compressor diagnostic method that diagnoses that wear has occurred in the internal parts of the compressor if the above ratio is greater than or equal to a preset threshold.

15. In Claim 10, A compressor diagnostic method for diagnosing wear of a fixed scroll and a slewing scroll, or an Oldham ring, constituting the compressor.

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