JPH0432238B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a compressor capable of being driven under inverter control, more specifically, a compressor comprising a compression element and a motor, and capable of controlling capacity by varying the rotational speed of the motor by frequency conversion. This invention relates to a compressor that performs the following steps.

(Prior art) Conventionally, this type of compressor is
As described in the publication and shown in FIG. 10, a compression element and a motor 3 are housed in a sealed casing 1, and the motor 3 and the compression element are interlocked and connected via a drive shaft 4, and the drive shaft 4 is formed with an oil supply passage 41 extending in the axial direction, and a bottom oil reservoir 1 of the casing 1 is formed at the lower end of the drive shaft 4.
A centrifugal pump P facing the direction a is installed, and as the drive shaft 4 is driven to rotate, the centrifugal pump P
, the lubricating oil in the oil reservoir 1a is transferred to the oil supply passage 4.
1 and from the oil supply passage 41 to the drive shaft 4.
The lubricating oil is supplied to the bearing parts of the compression element, the bearing parts of the compression element, and other lubricated parts.

(Problems to be Solved by the Invention) However, in the conventional compressor described above, since a centrifugal pump P is used to supply oil to each of the lubrication points, the following problems occur.

That is, the theoretical head (oil push-up value) due to the rotation of the centrifugal pump (P) is (H), the rotation speed of the pump (P) is (ω), and the inner diameter of the oil supply passage 41 in the drive shaft 4 is (r). ), and if the gravity that acts when pumping up lubricating oil is (g), then the theoretical head (H) is expressed as H=(r・ω) ² /2g.

Further, when the frequency of the motor 3 is (Hz), the rotation speed (ω) is expressed as ω=Hz/60×2π.

Since the amount of lubricating oil (Q) supplied by the centrifugal pump (P) is proportional to the theoretical head (H), it becomes Q∝(Hz) ² .

As is clear from the above equation, the amount of oil (Q) supplied to the centrifugal pump (P) is proportional to the square of the frequency (Hz) of the motor 3, so that the amount of oil supplied to the centrifugal pump (P) when the compressor is driven is The oil supply capacity of the engine is such that the oil supply amount (Q) increases in a quadratic manner as the frequency (Hz) increases.

Therefore, when the compressor is operated under inverter control,
When the motor 3 is operated in a high frequency range, the amount of oil supplied by the centrifugal pump P is significantly increased,
Excessive lubrication may be applied to each of the lubrication points, or excessive lubrication may increase the amount of lubricating oil mixed into the refrigerant gas discharged from the compressor, causing problems with oil drainage. As (Q) increases, a problem arises in that the amount of lubricating oil in the oil reservoir 1a in the casing 1 becomes insufficient.

In order to solve the various problems mentioned above, in place of the centrifugal pump (P), a constant displacement pump is capable of increasing the oil supply amount (Q) in a linear curve as the frequency (Hz) increases. However, simply using a constant displacement pump will not work because of the startup characteristics that allow oil to quickly reach each of the lubrication points at the initial startup of the motor 3 in the low frequency range. This was insufficient for improvement.

The present invention has been made in view of the above-mentioned problems, and its purpose is to use the centrifugal pump and constant displacement pump in combination to achieve the necessary power when the motor is operated in a low frequency range. To provide a compressor that can secure oil supply characteristics, allow oil to reach various lubrication points quickly, and prevent excessive oil supply when the motor is operated in a high frequency range. It is in.

(Means for Solving the Problems) As shown in the embodiment of the drawings, the compressor of the present invention includes a compression element 2 and a motor 3, and the capacity is controlled by changing the rotation speed of the motor 3 by frequency conversion. In the compressor, a refueling pump 5 equipped with a positive displacement pump element 6 whose volume can be varied by driving the drive shaft 4 is attached to the shaft end of the drive shaft 4 of the motor 3, and this refueling pump A centrifugal pump 7 is provided on the discharge side of the pump 5.

(Function) When the motor 3 is operated in a low frequency range, the centrifugal pump 7 provided in the oil supply pump 5 ensures a predetermined required head, so that there is no shortage of oil supply to the lubricating points. Moreover, the required amount of lubricating oil can be quickly reached, and when the motor 3 is operated in a high frequency range, since the oil supply pump 5 is equipped with a positive displacement pump element 6, it is possible to prevent excess oil from being supplied to the lubricating points. A predetermined amount of lubricating oil is supplied to this lubricating point without any movement.

(Example) A compressor according to the present invention will be described below with reference to an example shown in the drawings.

Figure 9 shows a scroll type compressor.
An upper frame 11 and a lower frame 12 are provided at upper and lower positions inside the sealed casing 1, respectively.
A motor 3 whose rotational speed is variable by frequency conversion is supported between the upper frame 11 and the lower frame 12. , are interlocked and connected by a drive shaft 4 supported by bearings on each of the frames 11 and 12, and by rotation of the drive shaft 4 as the motor 3 is driven, the revolving scroll 22 of the compression element 2 is moved relative to the fixed scroll 21. The scrolls 21 and 22 are driven to revolve, and the refrigerant gas is compressed between the two scrolls 21 and 22.

Further, an oil supply pump 5 facing the bottom oil reservoir 1a of the casing 1 is attached to the lower end of the drive shaft 4, and the lubricating oil in the oil reservoir 1a is supplied to the axial center of the drive shaft 4 through the oil supply pump 5. The oil is pumped up to an oil supply passage 41 formed through the interior, and from the oil supply passage 41 to the bearing parts of the drive shaft 4 and each of the frames 11 and 12, the bearing parts of the drive shaft 4 and the revolving scroll 22, and other lubrication parts. Then, the lubricating oil is supplied.

In the compressor as described above, the oil supply pump 5 is provided with a positive displacement pump element 6 whose volume can be varied by the rotational drive of the drive shaft 4, and a centrifugal pump 7 is provided on the discharge side of the oil supply pump 5.
.

As shown in detail in FIGS. 1 and 2, the oil supply pump 5 includes a pump housing 51 fixedly supported on the lower end surface of the lower frame 12 via fixing bolts B, and an oval pump chamber 52a. rice cake,
A cylinder 52 is supported by the housing 51 to freely reciprocate only in the short diameter direction, and a rotor is fixed to a position below the drive shaft 4 via a connecting cylinder 53 and eccentrically rotated in the pump chamber 52a of the cylinder 52. 54, and a pump spacer 55 fixed to the lower surfaces of the rotor 54 and the cylinder 52 with fixing bolts B.
It consists of

As is clear from FIG. 3, the housing 51 is integrally provided with a mounting piece 51b extending radially outward at the upper end of the cylindrical body 51a, and the mounting piece 51b is attached to the lower frame 12 with the fixing bolt B, and the cylindrical body 51
Extension pieces 51c, 51c extending downward are formed facing each other in a, and a guide groove 51d is provided at the lower end of each extension piece 51c.

Furthermore, as is clear from FIG. 4, the cylinder 52 has semicircular portions on both sides in the lateral direction, and the semicircular portions are connected by a straight line portion to form a laterally elongated oval shape. In addition to forming a pump chamber 52a, supporting pieces 52b, 52b are integrally provided on the outer circumferential portion of the cylinder 52 in the minor axis direction of the pump chamber 52a, that is, in the vertical direction in the figure. The support piece 52b is interposed in a guide groove 51d provided in each extension piece 51b of the housing 51, and the cylinder 52 is reciprocated by the guide groove 51d only in the short diameter direction of the pump chamber 52a. be.

Further, as is clear from FIGS. 5 and 6, the rotor 54 is integrally formed with an eccentric portion 54a eccentric to the axis of the drive shaft 4 at its lower end, and the eccentric portion 54a is connected to the cylinder 52. pump chamber 52a
By rotating the eccentric part 54a eccentrically within the pump chamber 52a, the eccentric part 54a is rotated eccentrically within the pump chamber 52a while moving the cylinder 52 in the short diameter direction of the pump chamber 52a.
2a is reciprocated in the long diameter direction to suction and compress lubricating oil, and a suction port 54 is provided at a location eccentric to the axis on the lower end surface of the eccentric portion 54a.
b and a discharge port 54c on the outer peripheral surface, and a suction passage 54d communicating with the suction port 54b and extending radially outward from below and the discharge port 54c inside the rotor 54. A discharge passage 54b is formed, which communicates with the oil supply passage 41 of the drive shaft 4, extends from the bottom to the top, and opens into the oil supply passage 41 of the drive shaft 4.

The cylinder 52 supported by the housing 51 and the pump chamber 52 of the cylinder 52
The above-mentioned positive displacement pump element 6 is formed by the eccentric portion 54a of the rotor 54 which reciprocates in the major diameter direction within the inside of the rotor 54, and its operation will be described in detail later.

Further, the discharge passage 54 in the rotor 54
The oil supply passage 41 for the drive shaft 4 is located inside the upper part of e.
A tapered opening surface 54f whose diameter widens in an inverted conical cross section toward the surface is provided, and by the opening surface 54f,
It forms the centrifugal pump 7 mentioned above, and its operation will be explained in detail later.

Further, the oil supply passage 41 of the drive shaft 4 is formed in the center of the drive shaft 4 along the axial direction thereof, and the discharge passage 54e of the rotor 54 is formed in the center of the drive shaft 4.
is formed concentrically with the axis of the drive shaft 4, and the discharge passage 54e opens into the oil supply passage 41 via the opening surface 54f.

Further, as shown in FIG. 7, the pump spacer 55 has an outer diameter of the pump chamber 52a of the cylinder 52.
A lubricating oil suction hole 55a is provided at a position facing the suction port 54b of the rotor 54, and a lubricating oil suction hole 55a is provided at two locations in the middle of the spacer 55. By forming mounting holes 55b through each mounting hole 55b and screwing the fixing bolts B from each mounting hole 55b to each mounting hole 54g formed in the rotor 54, the spacer 5 is fixed.
5 is integrally attached to the rotor 54, and this spacer 5
5, the cylinder 52 is supported by the housing 51.

Next, the operation of the oil supply pump 5 configured as above will be explained.

First, the action of the positive displacement pump element 6 will be explained as follows.
This will be explained based on FIG.

As shown in FIG. 5A, when the rotor 54 is rotated in the direction of the arrow and the cylinder 52 is located at the lowermost position, the eccentric portion 54a of the rotor 54 moves into the pump chamber 5 in the cylinder 52.
2a, on both sides of the pump chamber 52a in the lateral direction around the eccentric part 54a,
A right ventricle A and a left ventricle B are formed, each having a predetermined size. Lubricating oil is supplied to the right ventricle A from the suction port 54b through the suction passage 54d, and the left ventricle B is supplied with the lubricating oil through the suction passage 54d. and discharge passage 5
4e to the oil supply passage 41 of the drive shaft 4, and lubricating oil is discharged from the left ventricle B to the oil supply passage 41. Therefore, in the case of FIG. It is in the process of sucking lubricating oil,
Further, the left ventricle B is in the process of discharging lubricating oil.

After this, as shown in FIG. B, when the cylinder 52 is moved upward from the lowermost position by the rotation of the rotor 54, the left ventricle B of the pump chamber 52a is closed by the eccentric portion 54a of the rotor 54. , and the right ventricle A becomes larger, so that the left ventricle B has completed discharging the lubricating oil, and the right ventricle A has completed suctioning the lubricating oil.

Further, as shown in FIGS. B to C, when the cylinder 52 is positioned at the uppermost position due to the rotation of the rotor 54, the eccentric portion 54a of the rotor 54 is located at an intermediate portion of the pump chamber 52a in the cylinder 52. The suction port 54b communicates with the left ventricle B, and the right ventricle A communicates with the discharge port 54c. Therefore, in the case of Figure C, the left ventricle B is lubricated. The right ventricle is in the middle of sucking in oil, and the right ventricle is in the middle of discharging lubricating oil.

Further, as shown in FIGS. C to D, when the cylinder 52 is moved downward from the uppermost position due to the rotation of the rotor 54, the eccentric portion 54a of the rotor 54 causes the pump chamber 52a to
The right ventricle A is occluded, and the left ventricle B becomes large, so that the right ventricle A has completed discharging the lubricating oil, and the left ventricle B has completed suctioning the lubricating oil.

As described above, the pump chamber 52 of the cylinder 52
In a, by eccentrically rotating the eccentric portion 54a of the rotor 54, suction and discharge of lubricating oil are repeated in the left and right chambers A and B, and constant volume operation is performed by the volumetric pump element 6. It is.

That is, if the radius of the eccentric portion 54a of the rotor 54 is (R), the radius of the eccentric portion 54a of the rotor 54 is
The amount of eccentricity of the eccentric portion 54a with respect to a is (r),
If the thickness of the cylinder 52 is (L), two compressions are performed in the pump chamber 52a for each rotation of the rotor 54, so the amount of oil supplied by the volumetric pump element 6 (Q) is: It is expressed as Q=4R・r・L・2・60Hz, which is Q∝Hz.

As is clear from the above equation, the amount of oil supplied (Q) by the pump element 6 is directly proportional to the frequency (Hz) of the motor 3, so when the compressor is operated by the inverter, the frequency (Hz) of the motor 3 is Even if it is increased, the amount of oil supplied (Q) is increased only in a linear curve.

Next, the action of the centrifugal pump 7 mentioned above will be explained.

First, as shown in FIG. 8, the rotor 5
The lubricating oil discharged from the discharge port 54c of No. 4 to the discharge passage 54e is supplied to the lower end position of the inverted conical opening surface 54f formed at the inner upper part of the rotor 54. Since is rotated as the drive shaft 4 is driven,
The lubricating oil that has reached the lower end position of the opening surface 54f,
The centrifugal force accompanying the rotation of the rotor 54 lifts it upward along the opening surface 54f. Further, an oil supply passage 41 is formed inside the axial center of the drive shaft 4 and extends vertically and concentrically with the opening surface 54f.
The lubricating oil lifted up is lifted upward along the wall surface of the oil supply passage 41 and is supplied to each lubricating location.

As described above, by configuring the oil supply pump 5 by a combination of the volumetric pump element 6 and the centrifugal pump 7, the centrifugal pump 7 can lubricate each of the lubrication points when the compressor is operating in a low frequency range. In addition, when the compressor is operated in a high frequency range, the positive displacement pump element 6 can supply each lubricant to the required amount quickly. A predetermined amount of lubricating oil is supplied to the lubricated points without over-lubricating the lubricating points.

In the illustrated embodiment, a notch is formed in the upper outer peripheral wall of the rotor 54, and a circumferential groove 54 is formed between the notch and the connecting cylinder 53 that fixedly supports the rotor 54.
h, and the rotor 54 is formed by the circumferential groove 54h.
Dust and the like mixed in the lubricating oil supplied from the opening surface 54f to the oil supply passage 41 of the drive shaft 4 through the connecting cylinder 53 are stored therein.

(Effects of the Invention) As explained above, in the compressor according to the present invention, the drive shaft 4 of the motor 3 is equipped with a displacement pump element 6 at the shaft end of the drive shaft 4, the displacement of which is variable by driving the drive shaft 4. At the same time as installing pump 5,
Since the centrifugal pump 7 is provided on the discharge side of the oil supply pump 5, in other words, since the oil supply pump 5 is constructed by combining the positive displacement pump element 6 and the centrifugal pump 7, the low frequency range of the compressor is When the compressor is operated in a high frequency range, the oil can reach the lubricated points quickly without running out of oil, and when the compressor is operated in a high frequency range, there is no need to overlubricate the lubricated points. This made it possible to supply a predetermined amount of lubricating oil to the

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the main parts of the compressor according to the present invention, Fig. 2 is a bottom view thereof, Fig. 3 is a sectional view of the pump housing, Fig. 4 is a plan view of the cylinder, and Fig. 5
The figure is a sectional view of the rotor, Figure 6 is a bottom view of the rotor, Figure 7 is a plan view of the pump spacer, Figure 8 is a drawing showing the operating state of the positive displacement pump element, and Figure 9 is the overall structure of the compressor. FIG. 10 is a cross-sectional view showing a conventional example. 2... Compression element, 3... Motor, 4... Drive shaft, 41... Oil supply passage, 5... Oil supply pump, 51
... Pump housing, 52 ... Cylinder, 52
a...Pump chamber, 54...Rotor, 54a...Eccentric portion, 54b...Suction port, 54c...Discharge port, 54d...Discharge passage, 54e...Discharge passage, 54f...Opening surface, 6... Positive displacement pump element, 7... centrifugal pump.

Claims (1)

[Scope of Claims] 1. In a compressor that includes a compression element 2 and a motor 3, and performs capacity control by varying the rotation speed of the motor 3 by frequency conversion, the shaft end of the drive shaft 4 of the motor 3 , a compressor characterized in that a refueling pump 5 equipped with a displacement pump element 6 whose volume can be varied by driving the drive shaft 4 is installed, and a centrifugal pump 7 is provided on the discharge side of the refueling pump 5. . 2 The oil supply pump 5 is connected to the pump housing 51,
A cylinder 52 is provided with an oval pump chamber 52a and is freely supported by the housing 51 for only reciprocating motion in the short diameter direction, and a cylinder 52 is supported by the drive shaft 4 and has an axis eccentric to the axis of the drive shaft 4. The rotor 54 has an eccentric portion 54a having a suction port 54b and a discharge port 54c opened on its outer periphery, and a suction passage 54d that communicates with the suction port 54b and opens outward from the bottom. The compressor according to claim 1, further comprising: a discharge passage 54e communicating with the discharge port 54c and opening into the oil supply passage 41 of the drive shaft 4. 3. The oil supply passage 41 of the drive shaft 4 is formed at the center of the drive shaft 4, and the discharge passage 54e opens into the oil supply passage 41 at the center of the drive shaft 4. A compressor according to scope 2. 4. Claims 2 or 3, characterized in that the opening of the discharge passage 54e to the oil supply passage 41 is provided with a tapered opening surface 54f whose diameter increases toward the oil supply passage 41. Compressor as described.