Compressor and control method of compressor

Abstract

To provide a compressor and a control method of a compressor that improve the reliability of an operation under a high ambient temperature environment. An operation of an electric motor is controlled on the basis of either a normal operation mode or a heat safety mode in which a set pressure for regulating an operation of the electric motor according to a pressure in a tank for storing compressed air is lowered either when an ambient temperature exceeds a first temperature threshold value or when a difference between the ambient temperature and the temperature of a discharge section area exceeds a temperature difference threshold value for HS mode.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority from Japanese application JP2025-002348, filed on January 7, 2025, the content of which is hereby incorporated by reference into this application.BACKGROUND OF THE INVENTION1. Field of the Invention

[0002] The present invention relates to a compressor and a control method of a compressor.2. Description of the Related Art

[0003] A gas compressor for producing compressed gas used as a power source in a manufacturing line or as an air source for a machine tool, a press machine, air blow, and the like has been known.

[0004] In addition, there is a package type gas compressor in which a compressor body and a motor for driving the compressor body are provided and a control circuit, an operation panel, and the like are integrally accommodated in a package for space saving.

[0005] In these gas compressors, since the reliability and durability of the gas compressors deteriorate due to an increase in the ambient temperature of the gas compressors, reducing the load of the gas compressors is one of the solutions for continuing the supply of the compressed gas.

[0006] As a background art of the present invention, there is JP-2003-3981-A.

[0007] JP-2003-3981-A describes a control method of a compressor that prevents an emergency stop and continues an operation by reducing the rotational speed of a drive motor or lowering the compression pressure when a sensor-detected value of any of a discharge air temperature, a differential pressure, a coil temperature, and a current reaches a preset upper limit value.

[0008] JP-2003-3981-A describes an operation method of a screw compressor in which a compressed air temperature detected by an air temperature detection sensor, a first pressure and a second pressure detected by first pressure and second pressure detection sensors, a coil temperature detected by a coil temperature detection sensor, and a current of a drive motor detected by a current detection sensor are input to a controller to obtain a differential pressure between the first pressure and the second pressure, and when any of the compressed air temperature, the differential pressure, the coil temperature, and the current reaches a preset upper limit value, the mode is shifted to an operation load reduction mode in which the operation load of the screw compressor is reduced by the controller.Prior Art DocumentPatent Document

[0009] Patent Document 1: JP-2003-3981-ASUMMARY OF THE INVENTION

[0010] However, further improvement in reliability is required so as to operate a compressor without problems even under a higher temperature environment as compared with the time when JP-2003-3981-A was filed.

[0011] The present invention provides a compressor and a control method of a compressor that improve the reliability of an operation under a high ambient temperature environment.

[0012] The present invention includes a plurality of means for solving the above-described problem, and an example thereof is a compressor including: an electric motor; a compressor body that is driven by the electric motor and has a compressor mechanism for discharging compressed air; an ambient temperature sensor that measures an ambient temperature of the compressor; a discharge temperature sensor that measures a temperature of a discharge section area from which the compressed air is discharged; and a control section that controls an operation of the electric motor on the basis of a pressure in a tank for storing the compressed air and a set pressure, in which the control section controls an operation of the electric motor on the basis of either a normal operation mode or a heat safety mode in which the set pressure is lowered either when the ambient temperature exceeds a first temperature threshold value or when a difference between the ambient temperature and the temperature of the discharge section area exceeds a second temperature threshold value.

[0013] According to the present invention, it is possible to further improve the reliability of an operation under a high ambient temperature environment. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a perspective view for depicting an external appearance of a compressor in a first embodiment to which the present invention is applied;

[0015] FIG. 2 is a perspective view for depicting an internal configuration of the compressor in the first embodiment to which the present invention is applied;

[0016] FIG. 3 is a diagram for depicting a conceptual configuration of the compressor in the first embodiment to which the present invention is applied;

[0017] FIG. 4 is a diagram for depicting functional blocks of a control board in the compressor in the first embodiment to which the present invention is applied;

[0018] FIG. 5 is a diagram for depicting an outline of an operation of a heat safety mode mounted on the compressor in the first embodiment to which the present invention is applied;

[0019] FIG. 6 is a diagram for depicting an operation state flow in the compressor in the first embodiment to which the present invention is applied;

[0020] FIG. 7 is a perspective view for depicting an internal configuration of a compressor in a third embodiment to which the present invention is applied; and

[0021] FIG. 8 is a diagram for depicting an example of a second temperature threshold value for a lower limit set pressure for each unit in the compressor in the third embodiment to which the present invention is applied.DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Embodiments of a compressor and a control method of a compressor of the present invention will be described below by using the drawings. It should be noted that in the drawings used in the specification, the same or corresponding constitutional elements will be denoted by the same or similar reference numerals, and repeated description of these constitutional elements will be omitted in some cases.

[0023] In the following first to sixth embodiments, as a compression system of a compressor body, a package type compressor in which a compression chamber is configured between a fixed scroll and an orbiting scroll and a scroll compressor for compressing air by orbiting motion is stored in a housing will be described as an example, but the compressor of the present invention is not limited to the package type. Similarly, the present invention is not limited to the scroll compressor but can be applied to other compressors such as a reciprocating compressor, a screw compressor, and a turbo compressor. In addition, working fluid is not limited to air, and other gases are also applicable.First Embodiment

[0024] A first embodiment of a compressor and a control method of a compressor according to the present invention will be described by using FIG. 1 to FIG. 6.

[0025] First, the entire configuration of the compressor will be described by using FIG. 1 to FIG. 3. FIG. 1 is a perspective view for depicting an external appearance of a compressor 100 in the first embodiment, FIG. 2 is a perspective view for depicting an internal configuration of the compressor 100 in the first embodiment, and FIG. 3 is a diagram for depicting a conceptual configuration of the entire compressor related to the first embodiment.

[0026] The compressor 100 depicted in FIG. 1 and FIG. 2 is a single-stage compressor in which one compressor body 103 and one electric motor 104 are provided, and a front panel configuring a part of the housing thereof is attachable to and detachable from a housing other than the front panel by a holding mechanism such as screws. In addition, an operation section 117 for the user to operate the compressor 100 is provided on the front side.

[0027] As depicted in FIG. 3, the compressor 100 is provided with a filter 102, a compressor body 103, an electric motor 104, a check valve 105, an aftercooler 106, a tank 107, a dryer 108, a switch 110, a control board 111 for controlling an operation of the electric motor 104 on the basis of a pressure in the tank 107 for storing compressed air and a set pressure, a pressure sensor 112, a magnet switch 113, a body temperature sensor 114, an ambient temperature sensor 115, and the like.

[0028] In the compressor 100, as depicted in FIG. 3, air 101 supplied from the outside to the inside of the compressor 100 passes through the filter 102 and is then supplied to the compressor body 103.

[0029] The electric motor 104 and the compressor body 103 are wound with a belt, so that the power of the electric motor 104 is transmitted to the compressor body 103 to drive the compressor body 103, the air compressed in the compressor body 103 passes through the check valve 105 and the aftercooler 106, is temporarily stored in the tank 107, and is supplied to the outside as compressed air 109 after passing through the dryer 108.

[0030] In the compressor 100, an operation or stop of the entire compressor is operated by the switch 110 of the operation section 117, and operations of parts of each section of the compressor are controlled by the control board 111.

[0031] In addition, an intermittent operation of the compressor body 103 is controlled by issuing a command from the control board 111 to the magnet switch 113 according to the pressure in the tank 107 detected by the pressure sensor 112.

[0032] Further, the compressor 100 of the present embodiment is provided with a body temperature sensor 114 for measuring the side surface temperature of the compressor body 103 as the temperature of a discharge section area from which compressed air is discharged, and an ambient temperature sensor 115 for measuring the temperature of air near an intake port 118 as the ambient temperature of the compressor 100.

[0033] Then, in the case where the ambient temperature of the compressor 100 measured by the ambient temperature sensor 115 is out of the range of the specification of the compressor 100, control is performed so as to issue an alarm / abnormality, and moreover, in the case where the temperature difference between the ambient temperature and the temperature of the compressor body 103 measured by the body temperature sensor 114 exceeds a predetermined threshold value, control is performed so as to issue an alarm / abnormality in order to prevent a failure of the compressor body 103.

[0034] Since the temperature of the air discharged from the compressor body 103 is close to approximately 200°C, the temperature measured by the body temperature sensor 114 is close to approximately 100°C during the operation of the compressor 100. On the other hand, since the ambient temperature sensor 115 is provided in the vicinity of the intake port 118 of the housing, the temperature measured by the ambient temperature sensor 115 becomes the temperature of a place where the compressor 100 is operated, for example, approximately a room temperature (for example, within a range from 0°C to 40°C).

[0035] It should be noted that the discharge temperature measured by the body temperature sensor 114 is not limited to the side surface temperature of the compressor body 103, and it is possible to take a form of measuring the temperature of the constitutional element between the compressor body 103 and a portion immediately before the aftercooler 106 or the temperature of the compressed air itself therebetween.

[0036] Similarly, the ambient temperature measured by the ambient temperature sensor 115 is not also limited to the temperature of the air in the vicinity of the intake port 118, and it is also possible to take a form of directly measuring the temperature outside the housing in the vicinity of the intake port 118 or a form of measuring the ambient temperature in the housing other than the intake port 118.

[0037] FIG. 4 is a functional block diagram of the control board 111 in the first embodiment, and FIG. 5 is a diagram for depicting an outline of an operation of a heat safety mode (also described as “HS mode” in some cases) mounted on the compressor of the first embodiment.

[0038] As depicted in FIG. 4, the control board 111 is provided with, as functional configurations, a pressure control section 201, an ambient temperature judgment section 202, a pressure setting judgment section 203, a pressure setting changing section 204, a temperature difference judgment section 205, and a recording section 206.

[0039] The pressure control section 201 processes sensor inputs from the pressure sensor 112, the body temperature sensor 114, and the ambient temperature sensor 115, and commands opening and closing of the magnet switch 113.

[0040] The pressure control section 201 allows the temperature difference judgment section 205 to judge the difference between the ambient temperature and the temperature of the compressor body 103 as the discharge section area on the basis of the ambient temperature and pressure settings judged by the ambient temperature judgment section 202 and the pressure setting judgment section 203 and, if necessary, on the basis of the pressure settings changed by the pressure setting changing section 204, and executes an operation state flow of the compressor 100 depicted in FIG. 6.

[0041] Specifically, the pressure control section 201 of the control board 111 controls the operation of the electric motor 104 on the basis of either a normal operation mode or the heat safety mode in which the set pressure is lowered either when the ambient temperature exceeds a first temperature threshold value or when the difference between the ambient temperature and the temperature of the discharge section area exceeds a temperature difference threshold value for HS mode TDTH.

[0042] Here, the set pressure to be changed can be any one or more of an operation stop pressure (upper limit pressure) as a reference for stopping when the pressure of the tank 107 becomes a predetermined pressure or higher and an operation return pressure (lower limit pressure) as a reference for reactivating when the pressure of the tank 107 becomes a predetermined pressure or lower, but an example of a case where only the lower limit pressure is changed will be described in the present embodiment.

[0043] The normal operation mode is a mode in which a warning as an abnormal stop due to a high temperature is issued and the operation of the electric motor 104 is stopped to stop the operation of the compressor body 103 either when the ambient temperature exceeds the first temperature threshold value or when the difference between the ambient temperature and the temperature of the discharge section area exceeds a temperature difference threshold value for normal mode TDT.

[0044] On the other hand, the heat safety mode is common to the normal operation mode in that a warning as an abnormal stop due to a high temperature is issued and the operation of the electric motor 104 is stopped to stop the operation of the compressor body 103 either when the ambient temperature exceeds the first temperature threshold value or when the difference between the ambient temperature and the temperature of the discharge section area exceeds the temperature difference threshold value for HS mode TDTH.

[0045] The heat safety mode is different from the normal operation mode in that in the case where the ambient temperature exceeds the temperature difference threshold value for HS mode TDTH, the set pressure (the lower limit pressure in the present embodiment) is lowered by a predetermined value such that the return of the operation of the electric motor 104 is delayed and the temperature of the compressor body 103 hardly rises. In addition, in the case where the ambient temperature or the like does not exceed the temperature threshold value, the set pressure is returned to the original value.

[0046] It should be noted that since a device of the user connected to the downstream of the compressor 100 has a necessary air pressure, it is desirable to set a lower limit for the setting change value of the lower limit pressure so that the pressure does not become lower than the necessary pressure.

[0047] The temperature difference threshold value for HS mode TDTH according to the set pressure is recorded in the recording section 206 in the control board 111 as table data as depicted in, for example, FIG. 8 (third embodiment) to be described later.

[0048] As the heat safety mode, as depicted in, for example, FIG. 5, two modes can be set such that, in a first heat safety mode, the set pressure is lowered and the temperature threshold value is changed in the case where the ambient temperature is equal to or higher than 45°C and lower than 47°C and, in a second heat safety mode, the pressure is lowered and the temperature threshold value is changed in the case where the ambient temperature is equal to or higher than 47°C and lower than 50°C and the operation is immediately stopped when it is determined that the ambient temperature is equal to or higher than 50°C.

[0049] Further, in the heat safety mode in the present embodiment, when the compressor body 103 is driven in the heat safety mode, the control board 111 lowers the temperature difference threshold value for HS mode TDTH according to the set pressure in parallel with lowering the control pressure. Since the temperature of the compressor body 103 hardly rises during the heat safety mode, it is difficult to detect whether a load due to a high temperature is applied to the compressor. Therefore, the temperature difference threshold value for HS mode TDTH is lowered in order to detect a failure more accurately to prevent the compressor from operating even under such conditions where it is not originally desired to operate when the outside temperature is high.

[0050] The user can freely select, by the operation section 117, whether to operate in the normal operation mode or the heat safety mode, and the result selected by the user is stored in the recording section 206 of the control board 111.

[0051] Next, a flow of control of the compressor 100 of the present embodiment will be described by using FIG. 6. FIG. 6 is a conceptual diagram for depicting an operation flow of the compressor of the first embodiment. In FIG. 6, the operation subject of each step is each section in the control board 111, but will be described below as the control board 111.

[0052] As depicted in FIG. 6, first, after the flow is started (S301) and the operation of the compressor 100 is started (S302), the control board 111 judges whether or not the heat safety mode is enabled (S303). When it is judged to be enabled, the processing proceeds to Step S308. By contrast, when it is judged not to be enabled, the processing proceeds to Step S304, and the control shifts to the normal mode control.

[0053] In the normal mode control, the control board 111 judges whether or not a temperature difference TD between the ambient temperature measured by the ambient temperature sensor 115 and the temperature of the discharge section area measured by the body temperature sensor 114 is larger than the temperature difference threshold value for normal mode TDT (S305).

[0054] When it is judged in Step S305 that the temperature difference TD between the ambient temperature and the temperature of the discharge section area is larger than the temperature difference threshold value for normal mode TDT, the control board 111 gives a compressor body error flag (S331), issues an alarm / abnormality, and finishes the flow (S307).

[0055] On the other hand, when it is judged that the temperature difference TD is equal to or smaller than the temperature difference threshold value for normal mode TDT, the control board 111 loops the normal control mode (S306).

[0056] In the case where it is judged to be enabled in the validity judgement (S303) of the heat safety mode, the control board 111 shifts to the heat safety mode control (S308).

[0057] In the heat safety mode control, the control board 111 first judges whether or not an ambient temperature AT is equal to or higher that 45°C (S309).

[0058] When it is judged that the ambient temperature AT is lower than 45°C, the processing proceeds to Step S310, and the control board 111 judges whether or not the heat safety mode is disabled (S310). The control board 111 shifts to the normal mode control when it is judged that the heat safety mode is disabled (S304), and continuously loops the heat safety mode control when it is judged that the heat safety mode is enabled (S311).

[0059] On the other hand, when it is judged in Step S309 that the ambient temperature AT is equal to or higher than 45°C, the processing proceeds to Step S312, and the control board 111 then judges whether or not the ambient temperature AT is equal to or higher that 47°C (S312). When it is judged that the ambient temperature AT is equal to or higher than 45°C and lower than 47°C, the processing proceeds to Step S313, and the control board 111 judges whether or not a set value Pu of the lower limit pressure is equal to or smaller than 0.55 MPa (S313).

[0060] The control board 111 keeps the set value Pu as it is and advances the processing to Step S315A when it is judged that the set value Pu of the lower limit pressure is smaller than 0.55 MPa, and sets the lower limit pressure at 0.55 MPa (S314) when it is judged that the set value Pu is equal to or larger than 0.55 MPa and advances the processing to Step S315A.

[0061] In this manner, it is also desirable to provide a minimum reference value for the lower limit pressure of the set pressure in the heat safety mode. In addition, in the case where the lower limit pressure is equal to or smaller than the set value in the heat safety mode, the control board 111 desirably keeps the set value as it is, and desirably changes the set value only in the case where the set value is exceeded.

[0062] Thereafter, the control board 111 sets the temperature difference threshold value for HS mode TDTH that is the value according to the lower limit pressure (S315A), and shifts to first heat safety mode control (S316).

[0063] In the first heat safety mode control, the control board 111 judges whether or not the temperature difference TD between the ambient temperature measured by the ambient temperature sensor 115 and the temperature of the discharge section area measured by the body temperature sensor 114 is larger than the temperature difference threshold value for HS mode TDTH (S317).

[0064] When it is judged in Step S317 that the temperature difference TD between the ambient temperature and the temperature of the discharge section area is larger than the temperature difference threshold value for HS mode TDTH, the control board 111 gives a compressor body error flag (S331), and finishes the flow (S307).

[0065] On the other hand, when it is judged that the temperature difference TD is equal to or smaller than the temperature difference threshold value for HS mode TDTH, the control board 111 judges again whether or not the ambient temperature AT is lower than 45°C (S318). When it is judged that the ambient temperature AT is lower than 45°C, the processing proceeds to Step S333A to change the set value Pu of the lower limit pressure to a user set pressure and to increase the temperature difference threshold value for HS mode TDTH to the temperature difference threshold value for normal mode TDT (S333A), and then the processing proceeds to Step S310.

[0066] As described above, even after changing the set pressure according to the ambient temperature, it is desirable for the control board 111 to increase the set pressure and the temperature difference threshold value for HS mode TDTH to the temperature difference threshold value for normal mode TDT according to a subsequent ambient temperature.

[0067] On the other hand, when it is judged that the ambient temperature AT is equal to or higher than 45°C, the processing proceeds to Step S319, and the control board 111 judges whether or not the ambient temperature AT is lower than 47°C (S319). When it is judged that the ambient temperature AT is lower than 47°C, the processing proceeds to Step S310A, and the control board 111 judges whether or not the heat safety mode is disabled (S310A).

[0068] When it is judged that the heat safety mode is disabled, the processing proceeds to Step S333B, and the control board 111 changes the set value Pu of the lower limit pressure to the user set pressure and increases the temperature difference threshold value for HS mode TDTH to the temperature difference threshold value for normal mode TDT (S333B). Thereafter, the processing proceeds to Step S304 to shift to the normal mode control (S304). By contrast, when it is judged in Step S310A that the heat safety mode is enabled, the first heat safety mode control is continuously looped (S321).

[0069] On the other hand, when it is judged that the ambient temperature AT is equal to or higher than 47°C in Step S319, the processing proceeds to Step S320, and the control board 111 judges whether or not the ambient temperature AT is higher than 50°C (S320). When it is judged that the ambient temperature AT is higher than 50°C, an ambient temperature error flag is given (S332), an alarm / abnormality is issued, and the operation is finished (S307).

[0070] On the other hand, when it is judged that the ambient temperature AT is equal to or lower than 50°C, the processing returns to Step S309 without continuing the loop of the first heat safety mode, and the processing proceeds to processing of selecting which heat mode to be used.

[0071] When it is judged in Step S312 that the ambient temperature AT is equal to or higher than 47°C, the processing proceeds to Step S322, and the control board 111 judges whether or not the ambient temperature AT is equal to or higher that 50°C (S322). In the case where the ambient temperature is equal to or higher than 50°C, an ambient temperature error flag is given (S332), and the operation is finished (S307).

[0072] On the other hand, when it is judged that the ambient temperature AT is (equal to or higher than 47°C and) lower than 50°C, the processing proceeds to Step S323, and the control board 111 judges whether or not the set value Pu of the lower limit pressure is equal to or smaller than 0.45 MPa (S323).

[0073] The control board 111 keeps the set value Pu as it is and advances the processing to Step S315B when it is judged that the set value Pu of the lower limit pressure is smaller than 0.45 MPa, and sets the lower limit pressure at 0.45 MPa (S324) when it is judged that the set value Pu is equal to or larger than 0.45 MPa and advances the processing to Step S315B.

[0074] Thereafter, the control board 111 sets the temperature difference threshold value for HS mode TDTH that is the value according to the lower limit pressure (S315B), and shifts to second heat safety mode control (S325).

[0075] It should be noted that the temperature difference threshold value for HS mode TDTH set in Step S315A and the temperature difference threshold value for HS mode TDTH set in Step S315B are threshold values according to the lower limit pressures as described above, and are the same value if the lower limit pressures are the same set value, and are different values if the lower limit pressures are different set values.

[0076] In the second heat safety mode control, the control board 111 judges whether or not the temperature difference TD between the ambient temperature measured by the ambient temperature sensor 115 and the temperature of the discharge section area measured by the body temperature sensor 114 is larger than the temperature difference threshold value for HS mode TDTH (S326).

[0077] When it is judged in Step S326 that the temperature difference TD between the ambient temperature and the temperature of the discharge section area is larger than the temperature difference threshold value for HS mode TDTH, the control board 111 gives a compressor body error flag (S331), and finishes the flow (S307).

[0078] On the other hand, when it is judged that the temperature difference TD is equal to or smaller than the temperature difference threshold value for HS mode TDTH, the control board 111 judges again that the ambient temperature AT is lower than 45°C (S327). When it is judged that the ambient temperature AT is lower than 45°C, the processing proceeds to Step S333A to change the set value Pu of the lower limit pressure to the user set pressure and to increase the temperature difference threshold value for HS mode TDTH to the temperature difference threshold value for normal mode TDT (S333A), and then the processing proceeds to Step S310.

[0079] On the other hand, when it is judged that the ambient temperature AT is equal to or higher than 45°C, the processing proceeds to Step S328, and the control board 111 judges whether or not the ambient temperature AT is lower than 47°C (S328). When it is judged that the ambient temperature AT is lower than 47°C, the processing returns to Step S309 without continuing the loop of the second heat safety mode, and the processing proceeds to processing of selecting which heat mode to loop.

[0080] On the other hand, when it is judged that the ambient temperature AT is equal to or higher than 47°C in Step S328, the processing proceeds to Step S329, and the control board 111 judges whether or not the ambient temperature AT is higher than 50°C (S329). When it is judged that the ambient temperature is higher than 50°C, an ambient temperature error flag is given (S332), and the operation is finished (S307).

[0081] On the other hand, when it is judged that the ambient temperature AT is equal to or lower than 50°C in Step S329, the processing proceeds to Step S310B, and the control board 111 judges whether or not the heat safety mode is disabled (S310B).

[0082] When it is judged that the heat safety mode is disabled, the processing proceeds to Step S333B, and the control board 111 changes the set value Pu of the lower limit pressure to the user set pressure and increases the temperature difference threshold value for HS mode TDTH to the temperature difference threshold value for normal mode TDT (S333B). Thereafter, the processing proceeds to Step S304 to shift to the normal mode control (S304). By contrast, when it is judged in Step S310B that the heat safety mode is enabled, the second heat safety mode control is continuously looped (S330).

[0083] Next, effects of the present embodiment will be described.

[0084] The compressor 100 in the first embodiment of the present invention described above includes: the electric motor 104; the compressor body 103 that is driven by the electric motor 104 and has a compressor mechanism for discharging compressed air; the ambient temperature sensor 115 that measures the ambient temperature of the compressor 100; the body temperature sensor 114 that measures the temperature of the discharge section area from which the compressed air is discharged; and the control board 111 that controls an operation of the electric motor 104 on the basis of a pressure in the tank 107 for storing the compressed air and the set pressure, and the control board 111 controls an operation of the electric motor 104 on the basis of either the normal operation mode or the heat safety mode in which the set pressure is lowered either when the ambient temperature exceeds the first temperature threshold value or when the difference between the ambient temperature and the temperature of the discharge section area exceeds the temperature difference threshold value for HS mode TDTH.

[0085] In recent years, the rise in the maximum temperature in summer is remarkable, and users are demanding a compressor that operates without stopping as much as possible even at high temperatures. Meanwhile, by using the heat safety mode in which the set pressure is lowered in the case where the temperature is high, the amount of heat generated by the compressor can also be suppressed if the set pressure is lowered, so that the operation can be continued by moderating the temperature rise, and the reliability of the operation under a high ambient temperature environment can be further improved.

[0086] In addition, the control board 111 lowers the temperature difference threshold value for HS mode TDTH according to the set pressure when the compressor body 103 is driven in the heat safety mode. Since the operation is performed while suppressing the amount of heat generated in the heat safety mode described above, the operation may be continued in the heat safety mode even at a temperature at which the operation should be stopped due to a high temperature abnormality in the normal operation mode, and thus, in the control for detecting wear of a compressor by obtaining the difference between the discharged air temperature and the ambient temperature, changing a threshold value for detecting wear according to the set pressure value of the compressor when the set pressure is lowered makes it easier to stop the operation when the pressure is lowered, the compressor can be protected more appropriately at a high temperature, and higher reliability can be ensured even under a high ambient temperature environment than a conventional compressor.

[0087] Further, even after changing the set pressure according to the ambient temperature, the control board 111 increases the set pressure and increases the temperature difference threshold value for HS mode TDTH to the temperature difference threshold value for normal mode TDT according to a subsequent ambient temperature, so that it is possible to return a state in which the operation is suppressed when it is not necessary to operate in the heat safety mode to a normal state, and a stable operation can be realized.

[0088] In addition, a minimum reference value is provided for the lower limit pressure of the set pressure in the heat safety mode, so that a minimum required pressure is secured to prevent the supply of compressed air from stopping as much as possible, and it is possible to prevent the operation of a machine or the like on the use side of the compressed air from stopping as much as possible.

[0089] Further, the control board 111 can realize an operation according to settings of the user by keeping the set pressure (the upper limit pressure or the lower limit pressure) as it is when the set pressure is equal to or smaller than the set value in the heat safety mode and changing the set pressure when it exceeds the set value.Second Embodiment

[0090] A compressor and a control method of a compressor according to a second embodiment of the present invention will be described.

[0091] In the compressor 100 of the first embodiment described above, only the lower limit pressure is changed, the lower limit pressure serving as a reference for reactivating when the pressure in the tank 107 becomes a predetermined pressure or lower in the heat safety mode in which the set pressure for regulating the operation of the electric motor 104 according to the pressure in the tank 107 for storing compressed air is lowered. In a compressor of the present embodiment, however, the upper limit pressure is also changed simultaneously with the lower limit pressure, the upper limit pressure serving as a reference for stopping when the pressure in the tank 107 becomes a predetermined pressure or higher.

[0092] It should be noted that in the case where both the upper limit pressure and the lower limit pressure are changed, it is not necessary to change them simultaneously. In addition, it is possible to change only the upper limit pressure without changing the lower limit pressure.

[0093] Other configurations and operations are substantially the same as those of the compressor and the control method of the compressor in the first embodiment described above, and the details thereof will be omitted.

[0094] Even in the compressor and the control method of the compressor in the second embodiment of the present invention, it is possible to obtain substantially the same effects as the compressor and the control method of the compressor in the first embodiment described above.

[0095] In addition, by changing even the upper limit pressure, it becomes possible to more reliably protect the compressor at high temperatures.Third Embodiment

[0096] A compressor and a control method of a compressor in a third embodiment of the present invention will be described by using FIG. 7 and FIG. 8. FIG. 7 is a perspective view for depicting an internal configuration of the compressor in the third embodiment, and FIG. 8 is a diagram for depicting an example of a second temperature threshold value for the lower limit set pressure of each unit in the compressor of the third embodiment.

[0097] A compressor 100A of the present embodiment depicted in FIG. 7 has a plurality of compressor bodies 103A, 103B, and 103C. In such a compressor 100A, a control board 111A independently manages the temperature difference threshold value for HS mode TDTH for each of the compressor bodies 103A, 103B, and 103C.

[0098] Specifically, a body temperature sensor 114A is independently provided in the compressor body 103A, a body temperature sensor 114B is independently provided in the compressor body 103B, and a body temperature sensor 114C is independently provided in the compressor body 103C, and accordingly, the temperature difference threshold value for HS mode TDTH is independently managed.

[0099] As depicted in FIG. 8, the temperature difference threshold value for HS mode TDTH is changed according to the lower limit set pressure, and In the compressor body 103C located on the lowermost side in the vertical direction, the temperature difference threshold values for HS mode TDTH are set to be lower by 10°C in all the lower limit set pressures as compared with the compressor body 103B located at the center in the vertical direction, immediately thereabove, and are set to be lower by 5°C in all the lower limit set pressures as compared with the compressor body 103A located on the uppermost side in the vertical direction.

[0100] Other configurations and operations are substantially the same as those of the compressor and the control method of the compressor in the first embodiment or the second embodiment described above, and the details thereof will be omitted.

[0101] It should be noted that the compressor 100A of the present embodiment is not applied only to a configuration in which only the lower limit pressure is changed as in the compressor 100 of the first embodiment, but may be applied to a configuration in which both the upper limit pressure and the lower limit pressure are changed as in the second embodiment, or further may be applied to a configuration in which only the upper limit pressure is changed.

[0102] Even in the compressor and the control method of the compressor in the third embodiment of the present invention, it is possible to obtain substantially the same effects as the compressor and the control method of the compressor in the first embodiment or the second embodiment described above.

[0103] In addition, in the case where a plurality of compressor bodies 103A, 103B, and 103C are provided, the control board 111A independently manages the temperature difference threshold value for HS mode TDTH for each of the compressor bodes 103A, 103B, and 103C, so that it is possible to cope with a configuration in which the cooling efficiency differs depending on the arrangement position of the compressor body in the case where a plurality of compressor bodies are provided.Fourth Embodiment

[0104] A compressor and a control method of a compressor according to a fourth embodiment of the present invention will be described.

[0105] The compressor of the present embodiment is configured in such a manner that a function in which the temperature difference threshold value for HS mode TDTH for the set pressure is used as a variable is recorded in the recording section 206, unlike the compressor 100 of the first embodiment in which the temperature difference threshold value for HS mode TDTH is recorded as table data in the recording section 206 in the control board 111 according to the set pressure.

[0106] Other configurations and operations are substantially the same as those of the compressor and the control method of the compressor in any one of the first to third embodiments described above, and the details thereof will be omitted.

[0107] It should be noted that the configuration in which a function is employed as in the present embodiment is also effective in a configuration in which the upper limit pressure is also changed in addition to the lower limit pressure as in the second embodiment, a configuration in which only the upper limit pressure is changed, and further, in the multi-stage compressor 100A as in the third embodiment. In particular, in the case where the function is employed in the multi-stage compressor 100A as in the third embodiment, different functions can be employed in the respective compressor bodies 103A, 103B, and 103C. In addition, it is also possible to change a configuration in such a manner as using a table in a certain stage and using a function in another stage. Moreover, even in the case where the upper limit pressure is also changed as in the second embodiment in the multi-stage compressor 100A as in the third embodiment, different functions can be employed in the respective compressor bodies 103A, 103B, and 103C, and it is also possible to change a configuration in such a manner as using a table in a certain stage and using a function in another stage.

[0108] Even in the compressor and the control method of the compressor in the fourth embodiment of the present invention, it is possible to obtain substantially the same effects as the compressor and the control method of the compressor in any one of the first to third embodiments described above.Fifth Embodiment

[0109] A compressor and a control method of a compressor according to a fifth embodiment of the present invention will be described.

[0110] The compressor of the present embodiment is configured in such a manner that the temperature difference threshold value for HS mode TDTH is set by referring to other pressure values such as the average value of the lower limit pressures and the upper limit pressures or the average pressure during the operation of the compressor, as the set pressure when the compressor body 103 is driven in the heat safety mode, unlike the compressor according to any one of the first to fourth embodiments in which the temperature difference threshold value for HS mode TDTH is lowered according to the set pressure (lower limit pressure) when the compressor body 103 is driven in the heat safety mode. Further, it is possible to lower the temperature difference threshold value for HS mode TDTH according to the average value of the pressures in the tank 107 in a certain period in the past.

[0111] Other configurations and operations are substantially the same as those of the compressor and the control method of the compressor in the first to fourth embodiments described above, and the details thereof will be omitted.

[0112] It should be noted that it is possible to employ together with the compressor according to any one of the first embodiment to the fourth embodiment.

[0113] Even in the compressor and the control method of the compressor in the fifth embodiment of the present invention, it is possible to obtain substantially the same effects as the compressor and the control method of the compressor in the first to fourth embodiments described above.Sixth Embodiment

[0114] A compressor and a control method of a compressor according to a sixth embodiment of the present invention will be described.

[0115] The compressor of the present embodiment employs operation control by an inverter instead of the magnet switch 113, in the compressor according to any one of the first embodiment to the fifth embodiment. In the present embodiment, the reference for lowering the temperature difference threshold value for HS mode TDTH can be set by referring not only to the set pressure but also to the relation between the set pressure and the rotational speed, and the like.

[0116] Other configurations and operations are substantially the same as those of the compressor and the control method of the compressor in any one of the first to fifth embodiments described above, and the details thereof will be omitted.

[0117] Even in the compressor and the control method of the compressor in the sixth embodiment of the present invention, it is possible to obtain substantially the same effects as the compressor and the control method of the compressor in any one of the first to fifth embodiments described above.Other

[0118] The above-described embodiments merely depict specific examples to help understand the concepts of the present invention, and are not intended to limit the scope of the present invention. It is possible to add, delete, or convert various constitutional elements in the embodiments without departing from the gist of the present invention.

[0119] For example, the various functional sections described in each of the above embodiments may be realized by using a circuit. The circuit may be a dedicated circuit for realizing a specific function or a general-purpose circuit such as a processor.

[0120] In addition, at least a part of the processing in each of the above embodiments can be realized by using a general-purpose computer as basic hardware. A program for realizing the above processing may be provided by being stored in a computer-readable recording medium. The program is stored in a recording medium as a file in an installable format or a file in an executable format. The recording medium is a magnetic disk, an optical disk (CD-ROM, CD-R, DVD, or the like), a magneto-optical disk (MO or the like), a semiconductor memory, or the like. The recording medium may be any medium as long as it can store a program and can be read by a computer. In addition, a program for realizing the above processing may be stored on a computer (server) connected to a network such as the Internet and may be downloaded to a computer (client) via a network.Description of Reference Characters

[0121] 100, 100A: compressor

[0122] 101: air

[0123] 102, 102A, 102B, 102C: filter

[0124] 103, 103A, 103B, 103C: compressor body

[0125] 104, 104A, 104B, 104C: electric motor

[0126] 105, 105A, 105B, 105C: check valve

[0127] 106, 106A, 106B, 106C, 106D: aftercooler

[0128] 107: tank

[0129] 108: dryer

[0130] 109: compressed air

[0131] 110: switch

[0132] 111, 111A: control board (control section)

[0133] 111: pressure sensor

[0134] 113, 113A, 113B, 113C: magnet switch

[0135] 114, 114A, 114B, 114C: body temperature sensor (discharge temperature sensor)

[0136] 115: ambient temperature sensor

[0137] 117: operation section

[0138] 118: intake port

[0139] 201: pressure control section

[0140] 202: ambient temperature judgment section

[0141] 203: pressure setting judgment section

[0142] 204: pressure setting changing section

[0143] 205: temperature difference judgment section

[0144] 206: recording section

[0145] AT: ambient temperature

[0146] TDT: temperature difference threshold value for normal mode

[0147] TDTH: temperature difference threshold value for HS mode (second temperature threshold value)

Claims

1. A compressor comprising: an electric motor; a compressor body that is driven by the electric motor and has a compressor mechanism for discharging compressed air; an ambient temperature sensor that measures an ambient temperature of the compressor; a discharge temperature sensor that measures a temperature of a discharge section area from which the compressed air is discharged; and a control section that controls an operation of the electric motor on a basis of a pressure in a tank for storing the compressed air and a set pressure, wherein the control section controls an operation of the electric motor on a basis of either a normal operation mode or a heat safety mode in which the set pressure is lowered either when the ambient temperature exceeds a first temperature threshold value or when a difference between the ambient temperature and the temperature of the discharge section area exceeds a second temperature threshold value.

2. The compressor according to claim 1, wherein the control section lowers the second temperature threshold value according to the set pressure when the compressor body is driven in the heat safety mode.

3. The compressor according to claim 2, wherein the control section increases the set pressure and the second temperature threshold value according to a subsequent ambient temperature even after changing the set pressure according to the ambient temperature.

4. The compressor according to claim 1, wherein a minimum reference value is provided for a lower limit pressure of the set pressure in the heat safety mode.

5. The compressor according to claim 1, wherein the control section keeps a set value as it is when the set pressure is equal to or lower than a set value in the heat safety mode, and changes a set value when the set pressure exceeds the set value in the heat safety mode.

6. The compressor according to claim 1, wherein when a plurality of the compressor bodies are provided, the control section independently manages the second temperature threshold value for each compressor body.

7. A control method of a compressor provided with an electric motor, a compressor body that is driven by the electric motor and has a compressor mechanism for discharging compressed air, an ambient temperature sensor that measures an ambient temperature of a compressor, and a discharge temperature sensor that measures a temperature of a discharge section area from which the compressed air is discharged, the control method comprising: controlling an operation of the electric motor on a basis of either a normal operation mode or a heat safety mode in which a set pressure is lowered either when the ambient temperature exceeds a first temperature threshold value or when a difference between the ambient temperature and the temperature of the discharge section area exceeds a second temperature threshold value.

8. The control method of the compressor according to claim 7, wherein the second temperature threshold value is lowered according to the set pressure when the compressor body is driven in the heat safety mode.

9. The control method of the compressor according to claim 8, wherein the set pressure and the second temperature threshold value are increased according to a subsequent ambient temperature even after changing the set pressure according to the ambient temperature.

10. The control method of the compressor according to claim 7, wherein a minimum reference value is provided for a lower limit pressure of the set pressure in the heat safety mode.

11. The control method of the compressor according to claim 7, wherein, a set value is kept as it is when the set pressure is equal to or lower than a set value in the heat safety mode, and a set value is changed when the set pressure exceeds the set value in the heat safety mode.

12. The control method of the compressor according to claim 7, wherein when a plurality of the compressor bodies are provided, the second temperature threshold value is independently managed for each compressor body.

Images