JPH04101093A - scroll compressor - Google Patents

Abstract

PURPOSE:To prevent the burning accident or the like of a motor by detecting the current value to be supplied to the motor and also the compressed fluid pressure of a compressor body, and stopping the motor at the time of judging the reverse rotation of the motor on the basis of the detection signals. CONSTITUTION:An oil-cooled type scroll compressor is driven by a motor 24, and compressed air containing lubricating oil 14 is supplied to an air tank from a delivery pipeline 15 through an oil separating filter 12. During compression operation, the lubricating oil 14 in an oil separating tank 10 passes a temperature regulating valve 20 and is supplied to the compressor body 1 side through an oil cooler 18. In this case, the motor 24 is provided with a current sensor 32 serving as a current detecting means, and a pressure sensor 33 serving as a delivery pressure detecting means is provided at the intermediate part of the delivery pipeline 15. When the compressed air pressure does not reach the initial pressure value despite the motor 24 being rotated, the motor 24 is stopped since the motor 24 is judged to be in the reversely rotated state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scroll compressor, and particularly to a scroll compressor that can prevent reverse rotation of an electric motor.

[Prior Art] FIG. 4 shows an oil-cooled scroll air compressor as an example of a scroll compressor according to the prior art.

In the figure, reference numeral 1 denotes a scroll-type compressor body, and the compressor body 1 includes a cylindrical casing 2, a fixed scroll 3 fixed to the negative side of the casing 2 in the axial direction, and the other side of the casing 2 in the axial direction. A drive shaft 4 is rotatably inserted into the casing 2 via a bearing and has a crank at its tip end inside the casing 2, and a plurality of scrolls are rotatably supported by the crank of the drive shaft 4 and are connected to a fixed scroll 3. Compression chamber 5,5. ... and defines a back pressure chamber 6 within the casing 2; an orbiting scroll 7 that extends from the casing 2 to the fixed scroll 3 and communicates with the compression chamber 5 on the low pressure side;
and a discharge port 9 formed at the center of the fixed scroll 3 and communicating with the compression chamber 5 on the high pressure side.

On the other hand, 10 is an oil separation tank provided in the compressor main body 1 so as to accommodate the negative side of the compressor main body 1 in the axial direction, and the oil separation tank 10 is a bottomed cylindrical tank having an air outlet 11A. It consists of a main body 11, an oil separation filter 12 provided on one end side of the tank main body 11 so as to cover the air outlet 11A, and a discharge side cover 13 provided so as to cover the air outlet 11A. And the oil separation tank 10
is supplied into the compressor main body 1 to store lubricating oil 14 for lubricating, cooling, and sealing each part, and also to separate the lubricating oil 14 in the compressed air discharged from the discharge port 9 by an oil separation filter 12. It has become.

Reference numeral 15 indicates a discharge pipe connected to the discharge side cover 13 to discharge the compressed air purified within the oil separation tank 10, and the distal end side of the discharge pipe 15 is a branch pipe. A branch pipe on one side of the discharge pipe 15 is connected to an air tank (not shown), and a branch pipe on the other side, in which an unloading solenoid valve 16 is provided in the middle, is connected to the suction port 8 side of the compressor main body 1. .

Furthermore, 17 is an oil passage whose inlet 17A opens downward in the oil separation tank 10, and the oil passage 17 branches halfway into a casing communication part 17B, a fixed scroll communication part 17C, and a cooler communication part 17D. An oil cooler 18 is connected to the cooler communication section 17D, and a return pipe 19 from the oil cooler 18 is connected to the casing communication section 1.
It is connected in the middle of 7B.

Reference numeral 20 denotes a temperature regulating valve consisting of an inlet 17A, a casing communication section 17B, and a three-way valve provided in the oil passage 17 between the fixed scroll communication section 17C side and the cooler communication section 17D side. 20 functions to adjust the amount of oil flowing from the inlet 17A to the oil cooler 18 according to the temperature of the lubricating oil 14 on the oil separation tank 10 side. Moreover, 21 is an oil filter located in the middle of the oil passage 17 between the temperature adjustment valve 20 and the inlet 17A.

Further, 22 is a back pressure suction bypass that communicates between the suction port 8 and the back pressure chamber 6, which are in a negative pressure state during compression operation, and 23 is a normally closed type electromagnetic bypass provided in the middle of the back pressure suction bypass 22. A suction bypass valve composed of a valve is shown, and the suction bypass valve 23 opens for a predetermined period of time when a starting switch (not shown) is closed, and aims to reduce the starting load by guiding back pressure to the suction port 8. It looks like this.

Reference numeral 24 denotes an electric motor 24 mounted on the oil separation tank 10 and consisting of, for example, a three-phase induction motor.
is started by a start switch, and rotates the drive shaft 4 via pulleys 25, 26 and a drive belt 27.

The oil-cooled scroll compressor according to the prior art has the above-mentioned configuration, and when the operator closes the start switch, the drive shaft 4 is rotated by the electric motor 24, and the orbiting scroll 7 is rotated relative to the fixed scroll 3. By making a swirling movement, the air sucked through the suction port 8 is transferred to the compression chambers 5, 5.
．． ... and discharges the compressed air together with the lubricating oil 14 from the discharge port 9 into the oil separation tank 10. and,
The lubricating oil 14 in this compressed air is separated by an oil separation filter 12, and only the purified compressed air is sent to the discharge pipe 1.
5 to the air tank.

Further, during the above-described compression operation, the pressure of the air compressed within the compression chamber 5 applies a separating force to the orbiting scroll 7 to separate it from the fixed scroll 3 . For this reason, the pressure in the compression chamber 5 of the intermediate pressure section is introduced into the back pressure chamber 6 through a back pressure introduction hole (not shown) provided in the orbiting scroll 7 to balance the pressure with the compression chamber 5 side. This prevents the orbiting scroll 7 from floating up.

On the other hand, at startup, the compressed air in the compression chamber 5 of the intermediate pressure section flows into the back pressure chamber 6 through the back pressure introduction hole.
The pressure inside the compression chamber 5 on the highest pressure side, that is, on the discharge port 9 side does not rise. As a result, the pressure inside the back pressure chamber 6 becomes higher than that on the compression chamber 5 side, the pressure balance is disrupted, and the orbiting scroll 7
is pressed against the fixed scroll 3 side, giving an overload to the electric motor 24. Therefore, when the start switch is closed, the suction bypass valve 23 is opened for a certain period of time, and the air in the back pressure chamber 6 is circulated to the suction port 8 side to prevent back pressure from being generated. We are trying to reduce the burden on staff at the same time.

Further, during the above-described compression operation, the lubricating oil 14 in the oil separation tank 10 is fed under pressure to the compressor body 1 side via the oil passage 17, but when the lubricating oil 14 is at a predetermined temperature or higher, the temperature regulating valve 20 is supplied to the cooler communication part 17D side by
After being cooled by the oil cooler 18, from the return pipe 19 to the casing communication section 17B and the fixed scroll communication section 17C.
It is supplied to the compressor main body 1 side via.

In this way, the lubricating oil 14 supplied from the oil passage 17 into the compressor main body 1 lubricates, cools, and seals each part, and then returns to the oil separation tank 1 from the discharge port 9 together with compressed air.
discharged inside.

[Problem to be solved by the invention]

By the way, in the conventional method described above, when installing or replacing the electric motor 24, the three-phase AC power line (not shown) may be incorrectly wired to the electric motor 24. In this case, the operator closes the start switch without noticing, causing the electric motor 24 to rotate in the opposite direction, causing the drive shaft 4 to rotate in the opposite direction via the pulleys 25 and 26 and the drive belt 27.

For this reason, in the conventional technology, the orbiting scroll 7 rotates in the opposite direction to the fixed scroll 3, and not only is it impossible to perform a normal compression action, but also the electric motor 24 is overloaded without the surrounding workers noticing this abnormality. Overload occurs over time, causing an overcurrent to flow, which may burn out the electric motor 24, and the lubricating oil 14 is not supplied to both scrolls 3, 7, etc.
Cooling and lubrication properties are significantly reduced, causing both scrolls to 3°7
There is a problem in that galling, seizure, etc. occur, and the compressor main body 1 is significantly damaged.

The present invention has been made in view of the problems of the prior art described above, and the present invention can reliably prevent the electric motor from rotating in reverse, prevent overload from occurring on the electric motor, and furthermore, has the advantage of being able to prevent the electric motor from overloading. The object of the present invention is to provide a scroll compressor that can prevent galling and the like.

[Means to solve the problem]

The features of the configuration adopted by the present invention in order to solve the above-mentioned problems include a current detection means that detects the current value supplied to the electric motor and outputs a detection signal, and a current detection means that detects the current value supplied to the electric motor and outputs a detection signal, and a discharge pressure detection means for detecting the pressure of the compressed fluid and outputting a detection signal; and a discharge pressure detection means for detecting the pressure of the compressed fluid and outputting a detection signal; and a motor reversal determination means for stopping the motor.

[Operation] With the above configuration, when the electric motor rotates in reverse, the sliding resistance between the fixed scroll and the orbiting scroll increases, overloading the electric motor occurs, the current value increases, and the compressor Since the compressed fluid is no longer discharged from the discharge port of the main body, the motor reversal determining means determines whether the electric motor will rotate in reverse based on the current value of the electric motor detected by the current detecting means and the pressure of the compressed fluid detected by the discharge pressure detecting means. can be determined, and the electric motor can be stopped.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3. Note that the same reference numerals are given to the same components as those of the prior art described above, and the explanation thereof will be omitted.

In the figure, reference numeral 31 is a push button switch, etc., and is, for example, an activation switch provided on the operation panel of the package (not shown).As shown in FIG. 2, the activation switch 31 is connected to a lead wire ( (not shown). Then, when the operator closes the start switch 31, the electric motor 24 rotates, the drive shaft 4 is driven to rotate, and the compressor main body 1 performs a compression action.

Reference numeral 32 indicates a current sensor as a current detection means, which is a Hall element or the like attached to the electric motor 24, and the current sensor 32 is connected to the control unit 3 as shown in FIG.
It is connected to the input side of 4. Then, the current sensor 3
2 detects the current value ■ supplied to the electric motor 24 as an electric signal, and sends this detection signal to the control unit 34.
It is designed to output to.

Reference numeral 33 indicates a pressure sensor as a discharge pressure detection means provided in the middle of the discharge pipe 15, and the pressure sensor 33 is constituted by, for example, a semiconductor strain gauge type pressure sensor. As shown in FIG. 2, the pressure sensor 33 is connected to the activation switch 31. It is connected to the input side of the control unit 34 together with the current sensor 32, detects the pressure of the compressed air discharged from the discharge port 9 within the discharge pipe 15, and outputs the detected pressure signal P0 to the control unit 34 as an electric signal. It looks like this.

34 is an arithmetic circuit including a CPU and a ROM.

The control unit 34 is composed of a memory circuit such as a RAM, and a memory area 34A is provided in the memory circuit of the control unit 34. Further, the program shown in FIG. 3 is stored in the memory circuit of the control unit 34, and a predetermined current value I is stored in the memory area 34A.

etc. are memorized. The control unit 34 determines whether the electric motor 24 rotates in reverse based on the detection signals from the current sensor 32 and the pressure sensor 33, lights up a warning lamp 35 (described later), and stops the electric motor 24. ing.

35 is a warning lamp as a warning means connected to the output side of the control unit 34, and the warning lamp 35 is turned on by a control signal from the control unit 34.
It is designed to warn surrounding workers, and is attached to the operation panel of the package, for example.

The oil-cooled scroll air compressor according to this embodiment has the above-described configuration, and the drive shaft 4 is driven by the electric motor 24.
The basic operation of rotating the orbiting scroll 7 through the suction port 8, compressing the air sucked in from the suction port 8 in each compression chamber 5, and discharging it from the discharge port 9 is not substantially different from that of the prior art. .

Next, the motor reversal determination means will be explained with reference to FIG.

First, the control unit 34 reads a signal from the starting switch 31 in step 1, and determines whether the starting switch 31 is closed (on) in step 2. If rNOJ is determined in this step 2, the process returns to step 1 and reading of the signal of the starting switch 31 is repeated.

If rYEsJ is determined in step 2, the electric motor 24 is powered and started, and the process proceeds to step 3, where the pressure on the discharge pipe 15 side at the time when the electric motor 24 is started is detected by the pressure sensor 33. Pn
In step 4, this pressure value Pn is stored in the storage area 34A as an initial pressure value. Next step 5
Then, a predetermined current value I0 is read from the storage area 34A, and in step 6 the electric motor 2 detected by the current sensor 32 is
Read the current value of step 4, and in step 7, the electric motor 24
The current value I is the predetermined current value I. Determine whether it is larger than . When it is determined as rNOJ in this step 7,
Since the electric motor 24 is rotating normally, the process ends here.

On the other hand, when it is determined as rYESJ in this step 7,
This is a case where the electric motor 24 rotates in the opposite direction, or the back pressure or the pressure inside the chamber 6 increases, and the sliding resistance of both scrolls 3 and 7 increases, causing the electric motor 24 to be overloaded. Then, the process moves to step 8, where a timer t is set, and a predetermined time t specified in step 9 is set. Just wait for some time. Then, in step 10, a predetermined time t. After the elapsed time, the detected pressure P from the pressure sensor 33 is detected again. +1 is read, and in step 11 it is determined whether this pressure value P n + + is larger than the pressure value Pn (initial pressure value) at the time of startup stored in the storage area 34A. Here, the pressure value P after a predetermined time t0 has elapsed. . 1 is higher than the initial pressure value Pn (if it is not, it means that compressed air is not being discharged from the discharge port 9 even though the electric motor 24 is rotating, so the pressure inside the back pressure chamber 6 is higher than the initial pressure value Pn). rather than the pressure increase in the electric motor 2
4 is rotating in the opposite direction. Therefore, step 11
[If NOJ is determined, the process moves to step 12 to stop the electric motor 24, and in step 13, the warning lamp 35 is turned on to alert surrounding workers etc. to the electric motor 24.
Notify of abnormality.

On the other hand, if rYESJ is determined in step 11, this means that the electric motor 24 is rotating in the forward direction and compressed air is being normally discharged from the discharge port 9, so the process is terminated.

Thus, according to this embodiment, the current value ■ supplied to the electric motor 24 is detected by the current sensor 32, and this current value ■
and the predetermined current value■. The load condition of the electric motor 24 can be detected by comparing the t with the predetermined time t. By detecting the subsequent pressure value Pn+1 of the compressed air and comparing this pressure value Pn+ with the initial pressure value P, the state of the compression action of the compressor main body 1 can be detected,
By setting the load state of the electric motor 24 and the compression state of the compressor main body to the so-called rANDJ condition, reverse rotation of the electric motor 24 can be reliably determined, and the electric motor 24 can be promptly stopped to detect an abnormality. It is possible to effectively notify surrounding workers.

Therefore, according to this embodiment, it is possible to reliably prevent the electric motor 24 from rotating in reverse for a long time, prevent the electric motor 24 from being overloaded, and prevent burnout accidents. Lubricating oil 14 is applied to the fixed scroll 3. It is possible to prevent the compressor main body 1 from rotating in reverse for a long time without being supplied to the orbiting scroll 7 side.
To prevent galling and seizure between the fixed scroll 3 and the fixed scroll 3, to prevent damage to the compressor body 1, and to significantly improve the reliability and life of the oil-cooled scroll air compressor. I can do it.

In the above embodiments, the current sensor 32 as the current detection means was described as being composed of a Hall element, etc. However, instead of this, for example, an optical current sensor using the Faraday effect or the like, an ammeter or the like may be used. A meter relay or the like may also be used.

Further, in the embodiment described above, the pressure sensor 33 as the discharge pressure detection means is constituted by a semiconductor strain gauge type pressure sensor and is installed in the middle of the discharge pipe 15, but the present invention is not limited to this. Force balance type as pressure detection means,
Other pressure sensors, such as a capacitance type, may be used, and the pressure sensor may be provided inside the oil separation tank 10, the air tank, or the like.

Further, in the embodiment, the warning lamp 35 is used as a warning means.
However, instead of this, a warning buzzer, a voice synthesizer, a message display, etc. may be used.

On the other hand, in the embodiment described above, the back pressure suction bypass 22 is shown as being provided outside the casing 2 of the compressor main body 1, but it may be provided inside the casing 2 as an air passage.

Further, in the embodiment described above, the suction bypass valve 23 was described as being composed of a normally closed electromagnetic valve, but instead of this, the suction bypass valve may be composed of, for example, an air pilot type on-off valve.

Furthermore, in the above embodiments, an oil-cooled scroll air compressor was used as an example of the scroll compressor. It can also be applied to machines.

[Effects of the Invention] As described in detail above, according to the present invention, there is provided a current detection means that detects the current value supplied to the electric motor and outputs a detection signal, and a current detection means that detects the current value supplied to the electric motor and outputs a detection signal, and discharge pressure detection means for detecting fluid pressure and outputting a detection signal; and when determining whether the electric motor rotates in reverse based on the detection signal from the current detection means and the discharge pressure detection means, the electric motor Since it is constructed with a motor reversal determination means that stops the electric motor, even if the electric motor rotates in the reverse direction due to incorrect wiring, etc., the electric motor can be prevented from rotating in the reverse direction for a long period of time, and accidents such as burnout of the electric motor can be prevented. In addition to preventing such occurrences, it also prevents galling and seizure between the orbiting scroll and fixed scroll, prevents damage to the compressor body, and improves the reliability and lifespan of the scroll compressor. etc. can be improved.

[Brief explanation of drawings]

1 to 3 relate to an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of an oil-cooled scroll air compressor according to this embodiment, FIG. 2 is a block diagram showing the circuit configuration, and FIG. 4 is a flowchart showing a motor reversal determination process, and FIG. 4 is a longitudinal sectional view of an oil-cooled scroll air compressor according to the prior art. DESCRIPTION OF SYMBOLS 1... Compressor body, 2... Casing, 3... Fixed scroll, 4... Drive shaft, 5... Compression chamber, 7...
...Orbiting scroll, 8...Suction port, 9...Discharge port, 24...Electric motor, 31...Start switch, 3
2... Current sensor (current detection means), 33... Pressure sensor (discharge pressure detection means). Patent applicant Tokico Co., Ltd. agent
Patent Attorney Kazuhiko Hirose Figure 4A No. 4

Claims (1)

[Claims] A compressor body that compresses fluid sucked in from a suction port and discharges it to the outside from a discharge port, and an electric motor that rotates by power supply from the outside and drives the compressor body,
The compressor main body includes a casing, a fixed scroll fixed to the casing, and an orbiting scroll rotatably supported by the casing via a drive shaft and forming a plurality of compression chambers between the fixed scroll and the fixed scroll. In the scroll compressor, the scroll compressor comprises: current detection means for detecting the current value supplied to the electric motor and outputting a detection signal; and detecting the pressure of the compressed fluid discharged from the discharge port of the compressor main body. discharge pressure detection means for outputting a detection signal;
Scroll type, characterized in that it is comprised of the current detecting means and a motor reversal determining means for stopping the electric motor when reverse rotation of the electric motor is determined based on the detection signal from the discharge pressure detecting means. compressor.