JP2650951B2 - Scroll type fluid machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a positive displacement fluid machine, and more particularly to a scroll fluid machine suitable for a compressor, a vacuum pump, a blower and the like.

[Conventional technology]

A conventional device using a scroll type fluid machine as a compressor has a structure in which a motor and a compression mechanism are housed in a closed container as described in Japanese Patent Application Laid-Open No. 62-48979. Further, a conventional device used as a vacuum pump has a structure in which a pump portion and a motor are integrated as described in Japanese Patent Application Laid-Open No. 61-116089. When the scroll fluid machine stops, as typified by these two known technologies, the scroll fluid machine stops at an arbitrary rotation angle according to the conditions of the rotational inertia force and the load.

[Problems to be Solved by the Invention] Among the above prior arts, those described in Japanese Patent Application Laid-Open No. 62-48979 have been mainly invented in consideration of being used as a compressor for refrigeration / air conditioners. Here, the bypass passage of the compression element is set as one of the starting load reductions. In the case of a refrigeration cycle, a well-described “balance pressure activation” is performed, but at this time, the final pressure in the compression element does not match the pressure in the discharge line, and power loss usually occurs. It is. Therefore, the technique is a method for releasing gas during compression in order to avoid this. However, in the refrigerating machine cycle, the liquid refrigerant often fills the compression element from the suction line while the compressor is stopped. Then, in such a state (FIG. 5c)
When started, the liquid refrigerant is immediately compressed, so that an excessive pressure may be generated. However, in such a case, the conventional technology alone has a limitation in reducing the starting load due to the limitation of the bypass port. That is, such a phenomenon is likely to occur when the scroll compressor is stopped in the states shown in FIGS. 5C and 5D. In the state shown in FIGS. Refrigerant liquid accumulates in the outermost spaces 10-3 and 10-4,
At the time of startup, since the compression operation of the liquid refrigerant is performed, it is conceivable that an extremely large pressure is generated as compared with the case of gas compression. In the prior art, it was not sufficiently considered to take into consideration such a meshing state of the lap.

Furthermore, the one described in JP-A-61-116089 is described as being used as a vacuum pump. However, as described above, attention must be paid to controlling the stop state (rotation angle of the shaft). However, the meshing state of the laps can occur even at various rotation angles. In such a situation, if the stop state is (c) or (d) in FIG. 5, the atmosphere easily enters the spaces 10-3 and 10-4. In this case, the wrap side walls forming the spaces 10-3 and 10-4 due to the moisture in the atmosphere have a problem of corrosion such as rust. On the other hand, this side wall forms a circumferential sealing point in the engagement between the wraps,
It is a well-known fact that good surface conditions are required.
Therefore, when the lap side wall is corroded, the sealing performance is deteriorated at the above-mentioned sealing point, and the sliding condition is deteriorated, causing the occurrence of "galling".

An object of the present invention is to control the meshing state of the wrap at the time of stop, and to always form the outer peripheral contact point of the scroll wrap as shown in FIG. 5 (a) at the time of stop. That is, by forming in this manner, in the case of an air conditioner, it is possible to prevent the incompressible fluid such as the liquid refrigerant from entering the working chamber formed by the wrap. When using a vacuum pump, etc.,
Since the inner wall of the working chamber formed by the wrap can be shielded from the atmosphere, corrosion of the inner wall can be prevented. The above two points are typical objects of the present invention.

[Means for solving the problem]

The above object is achieved by using a DC motor (for example, a permanent magnet rotor motor in a rotating magnetic field motor) for a conventional scroll fluid machine and immediately detecting the rotation angle of the motor. This is achieved by providing an arithmetic device for calculating the above signal and a driving device for driving a motor in response to a signal from the arithmetic device or the like.

[Action]

By the interlocking operation of the DC motor, the rotational position detecting means, the signal operation device, the drive circuit and the like, the engagement state of the lap at the time of stop can be freely controlled. That is,
When the motor is stopped, the signal arithmetic unit recognizes the engagement between the laps by detecting the rotation angle and, based on the result, applies a torque to the motor to generate a constant rotation angle by the drive unit. A state in which the wrap end portion is closed as shown in FIG. Therefore, it is possible to prevent the invasion of the incompressible fluid into the compression working chamber and the intrusion of the atmosphere into the compression working chamber at the time of stoppage, and to prevent the occurrence of corrosion such as rust.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. The configuration of FIG. 1 is as follows. Fixed scroll 1
Has a suction port 3 at the outer periphery and a discharge port 4 at the center. The fixed scroll 1 is fixed to the frame 7 by bolts 24 and the like in a state where the orbiting scroll 2 and the spiral scroll are engaged with each other. The Oldham ring 5 is interposed between the frame 7 and the orbiting scroll 2 so as to prevent the orbiting scroll 2 from rotating during operation. A rolling bearing 19 is arranged at the center of the frame 7, and a sliding bearing element 11 is arranged at a lower portion thereof. Further, an electric element 12 is mounted at a lower end of the outer periphery of the frame by bolts. The drive shaft 6b is supported by bearings 19 and 11, and one end of the drive shaft 6b is connected to a crankshaft 6a eccentric to the drive shaft 6b. The crankshaft 6a engages with the orbiting bearing 9 to give the orbiting scroll 2 a turning motion. The drive shaft 6b is provided with a rotor of the electric element 12, so that a drive torque is applied. Further, a fine hole 21 is provided in the drive shaft 6,
One end is open to the refrigerating machine oil 13 and the other end is open to each bearing. Reference numeral 8 denotes a balance weight whose center coincides with the center of the drive shaft 6b and is mounted. Reference numeral 18 is also a balance weight, which is attached to the end face of the rotor fixed to the drive shaft 6. Reference numeral 16 denotes a rotation angle display disk 16 of the drive shaft 6 which is fixed to the drive shaft 6b and indicates the rotation angle or position of the drive shaft 6. The rotation position detecting element 17 is fixed to the stationary body so as to be located on the outer peripheral portion of the disk 16. Each of the above elements is a sealed container 20 having an inlet, an outlet, a hermetic terminal 22, and the like.
Is stored together with the refrigeration oil.

Next, the operation in FIG. 1 will be described. When the electric element 12 is driven by the electric power introduced from the hermetic terminal, the drive shaft 6 is rotated accordingly. As a result, the orbiting scroll 2 orbits, and the gas flowing in from the suction port is moved to the working chamber. It is compressed by 10 and discharged from the central discharge port 4. The discharged gas passes through the space in the closed container 20 and is discharged from the discharge port 15 to the outside of the device. On the other hand, electric elements
When the 12 rotates, the rotation angle indicating disk 16 also rotates at the same time, so that the position detecting element 17 generates a detection signal corresponding to the rotation, and the signal is transmitted by the cable 23. The rotation angle indicating disk 16 may be a gear-shaped disk, and the position detecting element 17 may be an electromagnetic pickup, a photo sensor using light, or the like.

Next, a method of driving the compressor shown in FIG. 1 will be described with reference to FIG. FIG. 2 shows the overall configuration of the drive control device of the compressor (70). Hereinafter, for the sake of explanation, the compressor is assumed to be 70, the compression element constituted by the fixed scroll 1, the orbiting scroll 2 and the like is 70-2, the electric motor is 70-1, and
The position detecting means composed of 16, 17 is denoted by 72.

 First, the direct voltage Ed is supplied to the inverter 62.

The inverter 62, the transistor TR ₁ to Tr ₆ and a 120 ° energization inverter constructed from a freewheeling diode D ₁ to D ₅ Tokyo, positive side transistor TR ₁ to Tr ₃ of the AC output voltage is DC voltage Ed The 120 ° conduction period is controlled by pulse width modulation and a chopper operation.

Moreover, in which low resistance R ₁ is connected between the common anode terminal of the reflux and the common emitters of the transistor TR ₁ to Tr ₅ diodes D ₁ to D _5.

The winding current flowing through the armature winding of the synchronous motor 70-1 is
Wherein also flows through the low resistance R _1, the voltage drop of the low-resistance R _1, in which the winding current I _L can be detected.

The control circuit for controlling the output torque of the synchronous motor 70-1 includes a micro computer 53, a synchronous motor 70-
The magnetic pole position detection circuit 54 related to the rotor position detection circuit for detecting the magnetic pole position of the first rotor, and controls the torque of the synchronous motor 70-1. Torque control unit 80 and transistors TR _{1 to} TR ₅
And a speed command circuit 56 for commanding a target rotation speed to the microcomputer 53, an electromagnetic pickup 72 for detecting fluctuations in the rotation speed of the rotating spindle, and a waveform shaping circuit 74. .

The magnetic pole position detecting circuit 54, as disclosed in JP-A-52-80415, the rotor position by using the filter circuit from the armature winding terminal voltage V _A ~V _C of the synchronous motor 70-1 This is a circuit for forming a corresponding position detection signal 65.

The microcomputer 53 includes a CPU 53a as an arithmetic unit, a memory (rom memory) ROM 53b in which information is written in advance, a RAM 53c as a readable / writable memory (ram memory), an interface 53d, and the like. They are connected by a data bus and a control bus (neither is shown). The ROM 53b stores a control program necessary for driving the synchronous motor 70-1 related to the brushless DC motor one rotation before or based on statistically processed data.

With the above configuration, the rotation position is calculated by the microcomputer 53 based on the signal from the position detection circuit 74, and the operation is stopped at the target rotation position. It becomes possible to make it as shown in FIG. Further, in order to perform a suitable operation, the following configuration can be adopted. That is, the rotation angle display disk 16 can be worked by the rotation position detection means 72 so that a signal of one pulse per rotation (1 P / rev) is obtained according to the meshing state of the scroll. On the other hand, when the computer 53 receives a manual stop signal or the like, even if the operation of the inverter 62 is stopped immediately, the compressor will not operate due to its own inertia and the reverse rotation caused by the discharged high-pressure gas. However, in this case, the following measures can be taken. First, the compressor
After the natural stop of the motor 70, the microcomputer 53 again controls the motor 70-
1 is slowly rotated, the reference position is confirmed by the position detecting means 72, and the operation is stopped. Finally, the power is cut off by a command from the microcomputer, and the operation is completely stopped.

Next, another embodiment will be described with reference to FIGS. 3 and 4. FIG. The configuration in FIG. 3 is basically substantially the same as that in FIG. 1, and therefore, different points will be mainly described. The entire compressor has an open configuration without a closed container.
A rotary encoder 25 serving as a rotational position detecting means is provided below the drive shaft 6, and emits rotation angle information of the drive shaft 6. 26 is a gas suction hole. With the operation of the orbiting scroll 2, the suction gas is supplied to the suction hole 26.
The orbiting scroll 2 passes through the flow path 27a on the outer periphery of the electric element 12 and further through the flow path 27b provided in the frame 7.
Reach the back of Then, it flows into the working chamber 10 through the suction port 28 (28a, 28b) provided in the orbiting scroll head surface, is compressed, and is discharged from the discharge port 15. Suction port 28
Are provided on the outer peripheral portion thereof in opposition to the scroll wrap winding end position 29, and are substantially symmetrical with each other.

The drive control circuit shown in FIG. 2 can also be used to drive and control this scroll machine. Therefore, description of the drive control method is omitted.

〔The invention's effect〕

According to the present invention, when the scroll fluid machine driven by the electric element is stopped, a constant rotation angle can be maintained at all times, that is, the state shown in FIG. The operation chamber 10-1 stops in a state in which the working fluid is taken. However, it is possible to deal with the matters described in the problem of the related art. That is, for air conditioners, there is a phenomenon that the liquid refrigerant returns to the suction side at the time of stoppage. In such a case, if the state is as shown in FIG. Will not come in. Therefore, when restarting, since the liquid refrigerant compression action is eliminated, the starting torque is much smaller than in the prior art. In addition, when applied to air compressors, vacuum pumps, blowers, etc., if the scroll wrap is closed and stopped, moisture in the atmosphere will not flow into the wrap during stoppage, and the inner wall of the working chamber will be blocked. Since it can protect against rusting, a normal sealing line can always be obtained, so that high performance can be maintained for a long time, and burn-in phenomenon between laps can be prevented, so high reliability can be obtained for a long time There is an effect that can be.

Further, as another effect, the electromagnetic torque of the motor can be controlled by the arithmetic unit and the control drive unit so that the position detection signal has a constant frequency, that is, the rotational speed of the drive shaft is constant. Therefore, the vibration synchronized with the driving rotation speed can be remarkably reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a scroll fluid machine showing an embodiment of the present invention, FIG. 2 is a schematic diagram of a drive control circuit of the embodiment of FIG. 1, and FIG. FIG. 4 is a vertical sectional view showing a practical example, FIG. 4 is a sectional view taken along line XX of FIG. 3, and FIG. 5 is a plan view showing a combined state of scroll wraps. 1 ... fixed scroll 2 ... orbiting scroll 5 ...
Oldham ring, 6 ... Drive shaft, 7 ... Frame, 10 ...
... working chamber, 12 ... electric element, 13 ... refrigerating machine oil, 14 ... closed container, (16, 17), 25, 72 ... rotation angle detecting means, 53 ...
... microcomputer, 62 ... inverter, 70 ... compressor unit, 74 ... position detection circuit.

Claims (1)

(57) [Claims] An orbiting scroll and a fixed scroll, each of which comprises a head plate, and a spiral wrap standing upright on the head plate;
The orbiting scroll is provided with an electric motor as a drive source for orbiting motion, and the two scrolls are combined with the wrap facing inward to perform the orbiting motion in a state where the rotation of the orbiting scroll is prevented with respect to the fixed scroll. In a scroll type fluid machine which performs a compressing operation by sequentially reducing a working chamber formed by scroll wraps, means for detecting a rotational position of the electric motor, and inputting the rotational position, the electric motor is formed by the two scroll wraps. A scroll-type fluid machine comprising means for controlling the electric motor such that a compression working chamber located at an outermost peripheral portion substantially stops forming a maximum volume.