JPH0432239B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a compressor that can be operated under inverter control, more specifically, a compressor element and a motor, and the number of revolutions of the motor can be varied by frequency conversion to reduce the volume. This invention relates to a compressor that is controlled.

(Prior art) Conventionally, this type of compressor is
As described in the above publication and as shown in FIG. An oil supply passage 41 extending in the axial direction is formed in the bottom oil reservoir 1a of the casing 1 at the lower end of the drive shaft 4.
A centrifugal pump P is installed facing the oil supply passage 41, and as the drive shaft 4 is driven to rotate, the centrifugal pump P transfers the lubricating oil from the oil reservoir 1a to the oil supply passage 41.
The lubricating oil is supplied from the oil supply passage 41 to the bearing locations of the drive shaft 4, the bearing locations of the compression element, and other lubricating locations.

(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 centrifugal pump P is (ω), and the oil supply passage 41 in the drive shaft 4 is
The theoretical head (H) is expressed as H=(r·ω) ² /2g, where (r) is the inner diameter of the lubricating oil, and (g) is the weight that acts when pumping up the lubricating oil.

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 oil supply amount (Q) of the centrifugal pump P is proportional to the square of the frequency (Hz) of the motor 3, so the oil supply capacity of the centrifugal pump P when the compressor is driven is As shown by the dotted line curve given as a reference example in Fig. 9, the amount of oil supplied (Q) increases as the frequency Hz increases.
increases in a quadratic manner.

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 (Q) is significantly increased, and the respective lubricating points are over-lubricated, and the excess oil is discharged from the compressor. The amount of lubricating oil mixed into the refrigerant gas increases, causing problems with oil drainage, and furthermore, as the amount of oil supplied (Q) increases, the amount of lubricating oil in the oil reservoir 1a in the casing 1 becomes insufficient. A problem arose.

Furthermore, this problem of increased oil supply in the high frequency range becomes even more pronounced when the centrifugal pump P is designed to ensure a minimum oil supply at the lowest operating frequency range (30Hz). Needless to say, the centrifugal pump P usually lacks the head (H) necessary to obtain a predetermined amount of oil supply in its low frequency range, and the minimum amount of oil supply must be ensured. This also makes it difficult.

Therefore, in the centrifugal pump P, an abnormal situation occurs in which the above-mentioned lubrication points cannot be supplied at all in the low frequency range.

The present invention has been made in view of the above problems, and its purpose is to provide a positive displacement pump element to the oil supply pump that linearly increases the amount of oil supplied as the frequency increases, thereby facilitating operation in a high frequency range. To provide a compressor that does not sometimes carry out excessive oiling and can also carry out oiling well in a low frequency range.

(Means for Solving the Problems) As shown in the embodiments of the drawings, the compressor of the present invention includes a compression element 2 and a motor 3.
In the compressor in which the rotation speed of the motor 3 can be adjusted by frequency conversion to perform volume control, a displacement pump element 6 is provided at the shaft end of the drive shaft 4 in the motor 3 and whose volume can be varied by driving the drive shaft 4. The present invention is characterized in that a lubricating oil supply pump 5 equipped with the above is attached.

(Function) Since the oil supply pump 5 includes the displacement pump element 6, even when the motor 3 is operated in a high frequency range, the amount of oil supplied by the oil supply pump 5 follows a linear curve. Therefore, the required amount of lubricating oil is supplied to the lubricating points without over-lubricating the lubricating points, and even in the low frequency range, the above-mentioned volume is increased. The amount of oil to be supplied corresponding to the volume of the shaped pump element 6 can be secured.

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

FIG. 10 shows the overall structure of a scroll compressor, in which there are
An upper frame 11 and a lower frame 12 are respectively provided,
A compression element 2 consisting of a fixed scroll 21 and a revolving scroll 22 is supported on this upper frame 11, and a motor 3 whose rotation speed is variable by frequency conversion is supported between the upper frame 11 and the lower frame 12. On the other hand, these motors 3 and compression elements 2
are interlocked and connected by a drive shaft 4 supported by bearings on each of the frames 11 and 12, and the revolution scroll 22 of the compression element 2 is connected to the fixed scroll 21 by rotation of the drive shaft 4 as the motor 3 is driven. Both scrolls 21,
The refrigerant gas is compressed between 22 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.

Therefore, in the above compressor, the oil supply pump 5 is equipped with a positive displacement pump element 6 whose volume can be varied by the rotational drive of the drive shaft 4.

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 54e is formed, which communicates with the oil supply passage 54e, 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, as shown in FIG. 7, the pump spacer 55 has an outer diameter equal to that 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 the mounting holes 55b and screwing the fixing bolts B from the mounting holes 55b to the mounting holes 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 constructed as above will be explained based on FIG. 8.

First, as shown in A of the figure, the rotor 54
is rotated in the direction of the arrow so that the cylinder 52 is located at the lowest position, the rotor 54
An eccentric portion 54a is located at an intermediate portion of the pump chamber 52a in the cylinder 52, and a right ventricle A and a left ventricle B, each having a predetermined size, are formed on both sides of the pump chamber 52a in the lateral direction around the eccentric portion 54a. is formed, and the suction port 54b is connected to this right ventricle A.
Lubricating oil is supplied from the left ventricle B through the suction passage 54d, and the left ventricle B is communicated with the oil supply passage 41 of the drive shaft 4 through the discharge port 54c and the discharge passage 54e, and the lubricant is supplied from the left ventricle B through the discharge port 54c and the discharge passage 54e. aisle 4
Therefore, in the case of Figure A, the right ventricle A is in the process of sucking in lubricating oil, and the left ventricle B is in the middle 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 intake 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 in the process of sucking in lubricating oil, and the right ventricle A 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 determined by the frequency of the motor 3.
Since it is directly proportional to Hz, even if the frequency Hz of the motor 3 is increased during inverter operation of the compressor, the amount of oil supplied (Q) is only increased linearly.

Next, the oil supply characteristic graph shown in FIG. 9 will be explained. This figure shows frequency (Hz) on the horizontal axis,
The vertical axis shows an oil supply characteristic graph in which the oil supply amount ratio is taken as 1 when operating at 30 (Hz). Note that the compressor is normally operated under inverter control in the range of 30 to 120 (Hz), so even when operating at 30 (Hz), the minimum amount of lubricating oil required at the lubricating points is In order to supply the same amount of oil, the amount of oil supplied is set based on the above-mentioned 30 (Hz).

As is clear from Figure 9 above, in the conventional system, the amount of oil supplied increases quadratically from the low frequency range to the high frequency range, as shown by the dotted line graph in the same figure, and excessive oil supply occurs when operating in the high frequency range. However, in the present invention, as shown by the solid line graph in the same figure, the amount of refueling increases in a linear curve from the low frequency range to the high frequency range. Even when the engine is operated in the region, the necessary predetermined amount of refueling is performed without overfilling.

Furthermore, even in the low frequency range, the positive displacement pump element 6
This makes it possible to ensure an amount of oil supplied that is commensurate with the volume of the pump chamber 52a that constitutes the pump chamber 52a.

In the embodiment shown in the drawings, a tapered opening surface 54f is provided inside the rotor 54 above the discharge passage 54e and has a diameter increasing toward the oil supply passage 41 of the drive shaft 4 so as to have an inverted conical cross section.
The centrifugal pump action is exerted by f.

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

In this way, the lubricating oil that has passed from the discharge port 54c of the rotor 54 through the discharge passage 54e and reached the lower end position of the opening surface 54f of the rotor 54 is transferred to the opening surface 54f due to the centrifugal force accompanying the rotation of the rotor 54. Moreover, since a refueling passage 41 is formed inside the axis of the drive shaft 4 and penetrates vertically concentrically with the opening surface 54f, the opening 54f The lubricating oil lifted up is lifted upward along the wall surface of the oil supply passage 41 and is supplied to each of the lubrication points.

Further, in the illustrated embodiment, a notch is formed in the upper outer circumferential wall of the rotor 54, and the notch and the rotor 5
A circumferential groove 54h between the connecting cylinder 53 that fixedly supports the
The circumferential groove 54h is configured to collect dust and the like mixed in the lubricating oil supplied from the opening surface 54f of the rotor 54 to the oil supply passage 41 of the drive shaft 4 via the connecting cylinder 53. ing.

(Effects of the Invention) As explained above, in the compressor according to the present invention, a lubricant oil is provided at the shaft end of the drive shaft 4 of the motor 3, which has a displacement pump element 6 whose volume can be varied by driving the drive shaft 4. Since the oil supply pump 5 is installed, even when the motor 3 is operated in a high frequency range, the amount of oil supplied by the oil supply pump 5 increases only in a linear curve. This makes it possible to supply only a predetermined amount of lubricating oil, and to reliably prevent over-lubricating the lubricating points.

Furthermore, even when operating in a low frequency range, a predetermined amount of oil can be ensured, and the lubricated parts can be well supplied with oil.

[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 a graph showing the oil supply characteristics. , FIG. 10 is a longitudinal sectional view showing the overall structure of the compressor, and FIG. 11 is a drawing showing a conventional example. 2...Compression element, 3...Motor, 4...Drive shaft, 5...Oil supply pump, 6...Displacement pump element.

Claims (1)

[Claims] 1 comprising a compression element 2 and a motor 3;
In the compressor, the rotation speed of which can be adjusted by frequency conversion to perform capacity control, a displacement pump element 6 is provided at the shaft end of the drive shaft 4 in the motor 3, the displacement pump element 6 having a variable volume by driving the drive shaft 4. A compressor characterized in that a lubricating oil supply pump 5 is attached.