JP2018035744A - Oil-sealed rotary vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil-sealed rotary vacuum pump that can use a plurality of kinds of battery packs with different rated voltages as a power source, and can restrain prolongation of time required for evacuation.SOLUTION: An oil-sealed rotary vacuum pump 1 comprises a fitting part, a determination unit 441, a voltage detection unit 45, a storage unit 43, and a driving control unit 442. A plurality of kinds of battery packs 9 with different rated voltages are detachably fitted to the fitting part. The determination unit 441 determines a kind of the battery pack 9 fitted to the fitting part out of the plurality of kinds of battery packs 9. The voltage detection unit 45 detects a voltage of the battery pack 9 fitted to the fitting part. The storage unit 43 stores a plurality of threshold voltages larger than overdischarge prevention voltages depending on the respective rated voltages of the plurality of kinds of battery packs 9. The driving control unit 442 stops rotation of a motor 31 when the voltage detected by the voltage detection unit 45 decreases to a threshold voltage corresponding to the battery pack 9 determined by the determination unit 441 out of the plurality of kinds of battery packs 9.SELECTED DRAWING: Figure 4

Description

  The present invention generally relates to an oil rotary vacuum pump, and more particularly to an oil rotary vacuum pump that uses a battery pack as a power source.

  Conventionally, a rotary airfoil oil rotary vacuum pump having a pump chamber, an oil tank, and a motor has been proposed as an oil rotary vacuum pump using a battery pack as a power source (Patent Document 1).

  The rotary airfoil oil rotary vacuum pump described in Patent Document 1 is a vacuum pump designed to evacuate a refrigerant pipe or the like of an air conditioner. The pump chamber includes a rotor having a central axis different from the central axis of the stator inside a stator having an intake port and an exhaust port. The rotor has two blades. The rotor rotates as the motor rotates. In the oil tank, oil used for airtightness between the components inside the pump chamber is accumulated.

JP 2008-180098 A

  In the field of oil rotary vacuum pumps, the viscosity of oil changes according to the ambient temperature, so pipes may not be able to be evacuated to the specified ultimate vacuum level of oil rotary vacuum pumps. The time spent was wasted.

  An object of the present invention is to provide an oil rotary vacuum pump that can use a plurality of types of battery packs having different rated voltages as a power source and can suppress an increase in time required for evacuation.

  The oil rotary vacuum pump according to one aspect of the present invention includes a rotor, a motor, and an oil tank. The oil rotary vacuum pump includes a mounting unit, a determination unit, a voltage detection unit, a storage unit, and a drive control unit. The mounting portion is detachably mounted with a plurality of types of battery packs that can supply power to the motor and have different rated voltages. The discriminating unit discriminates a type of the battery pack mounted on the mounting unit among the plurality of types of battery packs. The voltage detection unit detects a voltage of a battery pack mounted on the mounting unit among the plurality of types of battery packs. The said memory | storage part has memorize | stored the several threshold voltage larger than the overdischarge prevention voltage according to the rated voltage of each of the said multiple types of battery pack. The drive control unit stops the rotation of the motor when the voltage detected by the voltage detection unit decreases to a threshold voltage corresponding to the battery pack determined by the determination unit among the plurality of types of battery packs.

  The oil rotary vacuum pump of the present invention can use a plurality of types of battery packs having different rated voltages as a power source, and can suppress an increase in the time required for evacuation.

FIG. 1 is a perspective view of a state where a battery pack is mounted in an oil rotary vacuum pump according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the oil rotary vacuum pump with the battery pack removed. FIG. 3 is a perspective view of the battery pack in the oil rotary vacuum pump same as above. FIG. 4 is a circuit block diagram of a vacuum pump system including the above oil rotary vacuum pump. FIG. 5 is a circuit block diagram of a vacuum pump system including an oil rotary vacuum pump according to Embodiment 2 of the present invention.

(Embodiment 1)
Below, the oil rotary vacuum pump 1 of this embodiment is demonstrated based on FIGS.

  The oil rotary vacuum pump 1 is a rotary airfoil oil rotary vacuum pump and can operate from atmospheric pressure. The oil rotary vacuum pump 1 is a positive displacement vacuum pump that uses oil to reduce airtightness and ineffective space between components such as a rotor, a stator, and a blade. Here, the oil is a vacuum pump oil. The oil rotary vacuum pump 1 is used for, for example, a purpose of exhausting a gas (air or the like) in a refrigerant gas pipe in an air conditioner to evacuate the pipe.

  The oil rotary vacuum pump 1 includes a pump unit 2, a motor unit 3, a control unit 4, a mounting portion 5, an oil tank 6, a base 7, and a handle 8.

  The pump unit 2 includes a pump case 21 (chamber), a stator, a rotor, two vanes, and two coil springs. Parts such as a stator, a rotor, two blades, and two coil springs are arranged in the pump case 21. The stator has an intake port and an exhaust port. The rotor is disposed in the stator. The central axis of the rotor is eccentric from the central axis of the stator. The plurality of blades are held between the rotor and the inner surface of the stator, rotate together with the rotor, and have their tips slidably contact the inner surface of the stator.

  Each of the two blades is given a radially outward force from the center of the rotor by a coil spring housed in a groove formed in the outer peripheral surface of the rotor along the radial direction of the rotor, and the tip is It is in contact with the inner peripheral surface of the stator. The rotor is connected to the rotation shaft (shaft) of the motor 31 in the motor unit 3.

  In the pump unit 2, the two blades move along the inner peripheral surface of the stator due to the rotation of the rotor accompanying the rotation of the rotation shaft of the motor 31, so that the stator, the rotor, and the two blades are surrounded by the stator. The gas sucked into the space connected to the air inlet is compressed. In the pump unit 2, the gas is further compressed by further rotating the rotor. In the pump unit 2, when the space surrounded by the stator, the rotor, and the two blades is separated from the intake port, the exhaust valve is opened and the gas is exhausted from the exhaust port. The oil rotary vacuum pump 1 can evacuate the inside of the pipe by sucking air or the like in the pipe by repeating such exhaust.

  The pump unit 2 includes a suction port 26 provided in the upper part of the pump case 21. The internal space of the suction port 26 (connection pipe) is connected to the intake port of the stator. The pump unit 2 includes a valve 27 that opens and closes the internal space of the suction port 26. For example, a hose connected to an object to be evacuated, such as a refrigerant gas pipe, is connected to the suction port 26. Here, a hose may be connected to the suction port 26 via a valve with a vacuum gauge. Thereby, in oil rotary vacuum pump 1, it becomes possible for a person to check the degree of vacuum in piping by a vacuum gauge. In the oil rotary vacuum pump 1, the specified ultimate vacuum is 18 Pa. The ultimate vacuum is, for example, a vacuum measured by the above-described vacuum gauge. The oil rotary vacuum pump 1 is designed to achieve a specified ultimate vacuum at a standard temperature (for example, 20 ° C.). The allowable temperature range regarding the ambient temperature of the oil rotary vacuum pump 1 is, for example, 5 ° C to 40 ° C.

  The oil tank 6 is coupled to the pump unit 2. The oil tank 6 is disposed on the opposite side of the pump unit 2 from the motor unit 3 side. Here, the oil tank 6 is filled with oil used for airtightness between components inside the pump unit 2. An inlet for injecting oil into the oil tank 6 is provided in the upper part of the oil tank 6. In addition, a window 61 through which the amount of oil in the oil tank 6 can be visually recognized is provided on the side wall of the oil tank 6. The window 61 is provided with a level gauge indicating the amount of oil. A cap 62 including a discharge valve is provided at the inlet of the oil tank 6. In the oil tank 6, oil can be injected from the inlet by removing the cap 62 from the oil tank 6. A screw 63 to be removed when oil in the oil tank 6 is discharged is detachably attached to the lower portion of the oil tank 6. The amount of oil put into the oil tank 6 is, for example, 80 ml.

  The motor unit 3 includes a motor 31 (see FIG. 4) and a hollow cylindrical motor case 32 that houses the motor 31. The motor 31 rotates the rotor of the pump unit 2 around the central axis of the rotor. The motor 31 is a direct current motor. The motor case 32 has a first end and a second end in the axial direction. In the oil rotary vacuum pump 1, the first end of the motor case 32 is coupled to the pump case 21 of the pump unit 2. Here, the rotation shaft of the motor 31 disposed in the motor case 32 is fixed to the rotor. In the oil rotary vacuum pump 1, the second end of the motor case 32 is coupled to the control unit case 41 of the control unit 4.

  The control unit 4 includes a control unit case 41, a power switch 42, and a control circuit 44 (see FIG. 4). The power switch 42 is a mechanical switch operated by a user or the like. The control circuit 44 is configured to be able to drive the motor 31 by being supplied with power from the battery pack 9 attached to the attachment unit 5. Details of the control unit 4 will be described later.

  The oil rotary vacuum pump 1 includes a mounting portion 5 to which the battery pack 9 can be detachably mounted, and is configured to operate using the battery pack 9 mounted on the mounting portion 5 as a power source. In the oil rotary vacuum pump 1, when the power switch 42 is turned on in a state where the battery pack 9 is mounted on the mounting portion 5, the control circuit 44 operates and the rotating shaft of the motor 31 rotates. The number of rotations of the rotating shaft of the motor 31 is controlled by the control circuit 44.

  The battery pack 9 (see FIG. 3) includes a plurality of (for example, five) secondary batteries 90 (see FIG. 4), a rectangular parallelepiped housing body 91 that houses the plurality of secondary batteries 90, and a housing body 91. A flat rectangular parallelepiped protruding portion 92 protruding from a part of one surface 911. The secondary battery 90 is, for example, a lithium ion battery having a rated voltage of 3.6V. The housing main body 91 and the protruding base 92 have electrical insulation. In the battery pack 9, five secondary batteries 90 are connected in series in the housing body 91. As the battery pack 9, for example, a lithium ion battery pack having a rated voltage of 18.0V can be used. Here, as the battery pack 9, for example, EZ9L54 (product number) which is a lithium ion battery pack manufactured by Panasonic Corporation can be adopted. The battery pack 9 is not limited to a lithium ion battery pack with a rated voltage of 18.0V, but may be a lithium ion battery pack with a rated voltage of 14.4V, for example.

  The protrusion 92 has a first end 921 and a second end 922 in the longitudinal direction. In the battery pack 9, three insertion grooves 931, 932, and 933 are formed in the first end 921 of the projecting portion 92. In each of the three insertion grooves 931, 932, and 933, female connection terminals 961, 962, and 963 are accommodated. In addition, the battery pack 9 includes three L-shaped hooks 941, 942, 943 provided on each of the pair of side surfaces 923 in the short direction of the protrusion 92. Further, the battery pack 9 includes a lock portion 95 that is exposed from the one surface 911 of the housing main body 91 and disposed between the hook 942 and the hook 943. The lock portion 95 is inserted into a hole 915 in the wall including the one surface 911 of the housing main body 91, and a force in a direction protruding from the one surface 911 of the housing main body 91 is given by a return spring housed in the housing main body 91. ing. Here, the return spring is a compression coil spring. Further, the battery pack 9 includes a lock release operation unit 97 for releasing the lock state by the lock unit 95.

  As shown in FIG. 1, the battery pack 9 is detachably attached to the attachment portion 5. That is, the battery pack 9 can be attached to the mounting portion 5 and can be detached from the mounting portion 5.

  The mounting portion 5 includes a mounting base 51 as shown in FIG. The mounting base 51 has electrical insulation. The mounting base 51 is made of synthetic resin. The mounting base 51 has a recess 52 that accommodates the protrusion 92 of the battery pack 9. The opening shape of the recess 52 is rectangular. The recess 52 is open at one surface of the mounting base 51 opposite to the control unit 4 side and at one end in the longitudinal direction of the mounting base 51. The mounting portion 5 includes three hooks 541, 542, and 543 that are provided on each of the pair of inner side surfaces 53 in the short direction of the recess 52 and are respectively hooked on the hooks 941, 942, and 943 of the battery pack 9. Further, the mounting portion 5 is plugged into the communication connector 59 that can be connected to the communication connector 99 of the battery pack 9 and the two connection terminals 961, 962, 963 of the battery pack 9. Power supply terminals 551 and 552. Here, the connection terminal 961 is a positive power supply terminal of the battery pack 9. The connection terminal 962 is a negative power supply terminal of the battery pack 9. In short, when the battery pack 9 is attached to the attachment portion 5, the power supply terminal 551 is electrically connected to the positive connection terminal 961 of the battery pack 9, and the power supply terminal 552 is electrically connected to the negative connection terminal 962 of the battery pack 9. Connected. The communication connector 99 of the battery pack 9 is a connector for communicating battery information indicating information of the battery pack 9. The battery information includes temperature information, remaining capacity information, rated voltage information, rated capacity information, frequency information, and the like. The temperature information represents the temperature of the battery pack 9. The remaining capacity information represents the remaining capacity of the battery pack 9. The rated voltage information represents the rated voltage of the battery pack 9. The rated capacity information represents the rated capacity of the battery pack 9. The number information represents the number of times the battery pack 9 is charged.

  When the battery pack 9 is attached to the attachment portion 5, for example, the protrusion 92 of the battery pack 9 is set so that the hooks 941, 942, 943 of the battery pack 9 and the hooks 541, 542, 543 of the attachment portion 5 do not interfere with each other. It is inserted into the recess 52 of the mounting base 51 in the mounting part 5. Thereafter, the battery pack 9 can be mounted on the mounting portion 5 by shifting the battery pack 9 toward the first end 921 side of the projecting portion 92. When the battery pack 9 is attached to the attachment portion 5, the hooks 941, 942, 943 of the battery pack 9 are hooked on the hooks 541, 542, 543 of the attachment portion 5, respectively. Further, the lock portion 95 of the battery pack 9 is in a locked state in which the hook 543 of the mounting portion 5 hooked on the hook 943 of the battery pack 9 is locked.

  When removing the battery pack 9 from the mounting portion 5, for example, by operating a lock release operation portion 97 provided in the battery pack 9, the lock portion 95 disposed between the hook 942 and the hook 943 is returned to the return spring. Move against the spring force. Then, after the battery pack 9 is shifted to the second end 922 side of the protrusion 92, the battery pack 9 may be moved away from the inner bottom surface 521 of the recess 52 of the mounting base 51 of the mounting portion 5.

  The oil rotary vacuum pump includes a base 7 to which a pump unit 2 and a motor unit 3 are fixed. The base 7 is a pedestal for placing the oil rotary vacuum pump 1 in a stable state on the floor of the work place.

  The oil rotary vacuum pump 1 further includes a handle 8. The handle 8 is a component part of the oil rotary vacuum pump 1 that is held by a hand of a person carrying the oil rotary vacuum pump 1. The handle 8 is U-shaped, and has one end connected to the upper part of the pump case 21 and the other end connected to the upper part of the control unit case 41.

  Next, the above-described control unit 4 will be described in detail.

  In addition to the control unit case 41, the power switch 42, and the control circuit 44 (see FIG. 4), the control unit 4 includes a switching element 48, a power circuit 46, a voltage detection unit 45, and a storage unit as shown in FIG. 43 and the notification part 47 are provided.

  In the control unit 4, a series circuit of the power switch 42, the motor 31, and the switching element 48 is connected between the pair of power terminals 551 and 552.

  The switching element 48 is a MOSFET. The MOSFET constituting the switching element 48 is an n-channel enhancement type MOSFET. In the MOSFET constituting the switching element 48, one main terminal (source terminal) is electrically connected to the power supply terminal 552, the other main terminal (drain terminal) is electrically connected to the motor 31, and the control terminal (gate). Terminal) is electrically connected to the control circuit 44. The oil rotary vacuum pump 1 can control the rotation speed of the motor 31 by the control circuit 44 performing PWM control of the switching element 48.

  The power circuit 46 is connected between a pair of power terminals 551 and 552. The power supply circuit 46 is a constant voltage circuit that generates an operating voltage of the control circuit 44 from the output voltage of the battery pack 9 and supplies the operation voltage to the control circuit 44.

  The control circuit 44 includes a microcomputer. The microcomputer is configured as a one-chip device including a processor that operates according to a program, a memory that stores a program that operates the processor, and a working memory. The control circuit 44 can be realized by causing a microcomputer to execute a program.

  The control circuit 44 acquires battery information of the battery pack 9 via the communication connector 59 and the communication connector 99. For example, the battery pack 9 includes an identification resistor that is a resistance value corresponding to the value of the rated voltage, and the control circuit 44 detects the resistance value of the identification resistor included in the battery pack 9, thereby Get rated voltage information. The battery pack 9 monitors the voltage of each of the plurality of secondary batteries 90. When the voltage of at least one secondary battery 90 falls below a threshold value (for example, 2V), the secondary voltage in the battery pack 9 is secondary. The switching element provided between the series circuit of the battery 90 and the connection terminal 961 is turned off. Thereby, the battery pack 9 can prevent overdischarge of each of the plurality of secondary batteries 90. The threshold value is set so that the secondary battery 90 can be recharged and used even if the secondary battery 90 is self-discharged for a predetermined period (for example, two years).

  The oil rotary vacuum pump 1 can be used by mounting a plurality of types (for example, two types) of battery packs 9 having different rated voltages on the mounting portion 5. As an example, the oil rotary vacuum pump 1 can operate regardless of whether a lithium ion battery pack with a rated voltage of 18.0 V or a lithium ion battery pack with a rated voltage of 14.4 V is mounted as the battery pack 9.

  The voltage detection unit 45 detects the voltage of the battery pack 9 attached to the attachment unit 5 among the plurality of types of battery packs 9. Here, the voltage detection unit 45 detects the voltage of the battery pack 9 by detecting the voltage between the pair of power supply terminals 551 and 552. In the control unit 4, the voltage detection unit 45 is electrically connected to the control circuit 44, and the control circuit 44 can acquire the detection voltage of the voltage detection unit 45.

  The storage unit 43 stores a plurality of threshold voltages that are higher than an overdischarge prevention voltage (also referred to as a discharge limit voltage, an undercut voltage, or the like) corresponding to the rated voltage of each of the plurality of types of battery packs 9. The overdischarge prevention voltage of the battery pack 9 having a rated voltage of 18.0V is, for example, 12.5V. Moreover, the overdischarge prevention voltage of the battery pack 9 whose rated voltage is 14.4V is 10.0V, for example. In short, the overdischarge prevention voltage of the battery pack 9 is a value assuming that the voltage of each of the secondary batteries 90 is 2.5V. The threshold voltage of the battery pack 9 having a rated voltage of 18V is, for example, 16.0V. Further, the threshold voltage of the battery pack 9 having a rated voltage of 14.4V is, for example, 13.0V. In short, the threshold voltage of the battery pack 9 is a value obtained by setting each voltage of the plurality of secondary batteries 90 to 3.2V. Here, in the oil rotary vacuum pump 1, each threshold voltage is set so that the usable time can be shared in two consecutive hours regardless of the rated voltage of the battery pack 9. The storage unit 43 stores a plurality of rated voltages and a plurality of threshold voltages in advance in a one-to-one relationship. That is, the storage unit 43 stores the first rated voltage (18.0V) and the corresponding first threshold voltage (16.0V) in association with each other, and stores the second rated voltage (14.4V). ) And the corresponding second threshold voltage (13.0 V).

  The control circuit 44 includes a determination unit 441 that determines the type of the battery pack 9 and a drive control unit 442 that performs drive control of the motor 31.

  The determination unit 441 determines the type of the battery pack 9 attached to the attachment unit 5 among the plurality of types of battery packs 9. More specifically, the determination unit 441 acquires the rated voltage information of the battery pack 9 by detecting the resistance value of the identification resistor included in the battery pack 9, and determines the rated voltage of the battery pack 9 as the type of the battery pack 9. It is determined as

  For example, when the rated voltage of the battery pack 9 determined by the determination unit 441 is 18V, the drive control unit 442 performs PWM control on the switching element 48 so that the rotation speed of the motor 31 is 1900 rpm. For example, when the rated voltage of the battery pack 9 determined by the determination unit 441 is 14.4 V, the drive control unit 442 performs PWM control of the switching element 48 so that the rotation number of the motor 31 is 1520 rpm.

  The drive control unit 442 stops the rotation of the motor 31 when the voltage detected by the voltage detection unit 45 decreases to the threshold voltage corresponding to the battery pack 9 determined by the determination unit 441 among the plurality of types of battery packs 9. Here, the drive control unit 442 stops the rotation of the rotation shaft of the motor 31 by turning off the switching element 48. Therefore, the oil rotary vacuum pump 1 is supplied with power from the battery pack 9 without being able to evacuate the piping or the like to the specified ultimate degree of vacuum when the ambient temperature is too low and the viscosity of the oil becomes too high. It is possible to suppress the evacuation from being continued until is stopped. In short, when the oil rotary vacuum pump 1 is used in an environment in which the pump performance is low, the oil rotary vacuum pump 1 is longer than the above-described usable period (for example, (3 hours) It is possible to suppress the continuous operation.

  The notification unit 47 includes an LED (Light Emitting Diode) provided in the control unit case 41. The notification unit 47 is controlled by the drive control unit 442. When the voltage detected by the voltage detection unit 45 drops to a threshold voltage corresponding to the battery pack 9 determined by the determination unit 441 among the plurality of types of battery packs 9, the drive control unit 442 before stopping the motor 31. The notification unit 47 is operated so that the LED of the notification unit 47 blinks or lights for a predetermined time (for example, 20 seconds). The notification unit 47 is not limited to the LED, and may be configured to perform notification using a buzzer or the like.

  The oil rotary vacuum pump 1 described above has a rotor, a motor 31 and an oil tank 6. The oil rotary vacuum pump 1 includes a mounting unit 5, a determination unit 441, a voltage detection unit 45, a storage unit 43, and a drive control unit 442. The mounting unit 5 is detachably mounted with a plurality of types of battery packs 9 that can supply power to the motor 31 and have different rated voltages. The determination unit 441 determines the type of the battery pack 9 attached to the attachment unit 5 among the plurality of types of battery packs 9. The voltage detection unit 45 detects the voltage of the battery pack 9 attached to the attachment unit 5 among the plurality of types of battery packs 9. The storage unit 43 stores a plurality of threshold voltages larger than the overdischarge prevention voltage corresponding to the rated voltage of each of the plurality of types of battery packs 9. The drive control unit 442 stops the rotation of the motor 31 when the voltage detected by the voltage detection unit 45 decreases to the threshold voltage corresponding to the battery pack 9 determined by the determination unit 441 among the plurality of types of battery packs 9.

  With the above configuration, the oil rotary vacuum pump 1 can use a plurality of types of battery packs having different rated voltages as a power source, and can suppress an increase in time required for evacuation. Thereby, in the oil rotary vacuum pump 1, it is possible to prevent the useless evacuation from being continued.

  In the oil rotary vacuum pump 1, the control unit 4 includes a notification unit 47, and the drive control unit 442 operates the notification unit 47 for a predetermined time when the voltage detected by the voltage detection unit 45 decreases to the threshold voltage. The rotation of the motor 31 is stopped. The threshold voltage used in the drive control unit 442 is stored in the storage unit 43 described above. The notification unit 47 includes an LED (Light Emitting Diode). The drive control unit 442 operates the notification unit 47 so that the LED of the notification unit 47 blinks. Thereby, in the oil rotary vacuum pump 1, the user of the oil rotary vacuum pump 1 can know in advance that the oil rotary vacuum pump 1 stops.

  The oil rotary vacuum pump 1 preferably includes a notification unit 47. In the oil rotary vacuum pump 1, the drive control unit 442 preferably stops the rotation of the motor 31 after operating the notification unit 47 for a predetermined time when the detection voltage of the voltage detection unit 45 decreases to the threshold voltage. Thus, the oil rotary vacuum pump 1 can notify the user or the like that the motor 31 is to be stopped before the motor 31 is stopped.

(Embodiment 2)
Hereinafter, the oil rotary vacuum pump 1a of this embodiment will be described with reference to FIG.

  The basic configuration of the oil rotary vacuum pump 1a of the present embodiment is substantially the same as that of the oil rotary vacuum pump 1 of the first embodiment. The oil rotary vacuum pump 1a according to the present embodiment is different from the oil rotary vacuum pump 1 according to the first embodiment in that a temperature sensor 49 is further provided. Regarding the oil rotary vacuum pump 1a of the present embodiment, the same components as those of the oil rotary vacuum pump 1 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The temperature sensor 49 is a sensor that detects the ambient temperature of the oil rotary vacuum pump 1a (in other words, the temperature of the environment in which the oil rotary vacuum pump is used). The temperature sensor 49 is, for example, a thermistor. For example, the temperature sensor 49 is provided in the control unit case 41 and is electrically connected to the control circuit 44.

  The oil rotary vacuum pump 1a of this embodiment further includes a temperature sensor 49 that detects the ambient temperature, and the threshold voltage used in the drive control unit 442 is a specified ultimate vacuum (for example, 18 Pa) at the temperature detected by the temperature sensor 49. Is a value set so that can be obtained. Thereby, the oil rotary vacuum pump 1 becomes easier to achieve the specified ultimate vacuum.

  The oil rotary vacuum pump 1a is designed to achieve a specified ultimate vacuum at a standard temperature (for example, 20 ° C.). The oil rotary vacuum pump 1a has a tendency that the pump performance decreases as the temperature detected by the temperature sensor 49 is higher. Therefore, the threshold voltage is set higher as the detected temperature is higher. For example, when the rated voltage of the battery pack 9 is 14.4 V, the threshold voltage when the detected temperature is 5 ° C. or higher and lower than 25 ° C. is 13.0 V, and the threshold temperature when the detected temperature is 25 ° C. or higher and lower than 35 ° C. The threshold voltage when the voltage is 13.2 V and the detected temperature is 35 ° C. or higher and lower than 40 ° C. is 13.6 V. When the rated voltage of the battery pack 9 is 18.0 V, the threshold voltage when the detected temperature is 5 ° C. or higher and lower than 25 ° C. is 16.0 V, and the threshold temperature when the detected temperature is 25 ° C. or higher and lower than 35 ° C. The threshold voltage when the voltage is 16.5 V and the detected temperature is 35 ° C. or higher and lower than 40 ° C. is 17.0 V.

  The oil rotary vacuum pump 1 can be used not only for evacuation of the refrigerant gas piping of the air conditioner but also for evacuation of other devices and piping.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made according to design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it can be changed.

DESCRIPTION OF SYMBOLS 1, 1a Oil rotary vacuum pump 5 Mounting part 9 Battery pack 31 Motor 43 Storage part 45 Voltage detection part 47 Notification part 441 Discrimination part 442 Drive control part

Claims (3)

An oil rotary vacuum pump having a rotor, a motor and an oil tank,
A mounting portion that can supply power to the motor and that is detachably mounted with a plurality of types of battery packs having different rated voltages;
A determination unit for determining a type of the battery pack mounted on the mounting unit among the plurality of types of battery packs;
A voltage detection unit for detecting a voltage of the battery pack mounted on the mounting unit among the plurality of types of battery packs;
A storage unit storing a plurality of threshold voltages larger than an overdischarge prevention voltage corresponding to a rated voltage of each of the plurality of types of battery packs;
A drive control unit that stops rotation of the motor when the voltage detected by the voltage detection unit drops to a threshold voltage corresponding to the battery pack determined by the determination unit among the plurality of types of battery packs. Oil rotary vacuum pump characterized by With a notification unit,
2. The oil rotary vacuum pump according to claim 1, wherein the drive control unit stops the rotation of the motor after operating the notification unit for a predetermined time when the detection voltage drops to the threshold voltage. . A temperature sensor for detecting the ambient temperature;
3. The oil rotary vacuum pump according to claim 1, wherein the threshold voltage used in the drive control unit is a value set so as to obtain a specified ultimate vacuum at a temperature detected by the temperature sensor. .

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