Positive displacement pump

[Name of invention]

fusion pump

[Brief Description of Drawings]

1 is a side view of the shaft end;

Fig. 2 is an end view of the axial end of Fig. 1;

Fig. 3 is a cross-sectional view taken along line 3-3 of Fig. 2;

4 is an end view of the pivot ring;

5 is an end view of the eccentric rotor;

Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 5;

7 is an end view of the end cap.

8 is a cross-sectional view of the pump assembly;

9a to 9d are cross-sectional views showing the axis rotated at intervals of 90° along line 9-9 of FIG. 8,

Fig. 9a is a view exactly corresponding to Fig. 8;

Fig. 10 is a view showing a position in a reverse rotation state substantially corresponding to the position of Fig. 9c;

* Explanation of symbols for main parts of the drawing

10 : Pump 12 : Shaft

12-2: shoulder 12-3: shaft end

12-4,12-5: groove 12-6,12-8,16-1,16-2,18-2,20-1,20-2, 20-3: bore

12-8, 12-9: passage 14: pin

16 : pivot ring 18 : rotor

18-5: slot 20: end cap

22 : support 24,26 : bolt

30 : Oil reservoir 32,34 : Chamber

[Detailed Description of the Invention]

A fluid machine such as a compressor is typically lubricated by oil discharged from a reservoir by a pumping structure coupled to a crankshaft. Positive displacement pumps such as centrifugal pumps and gerotors are commonly used to pump oil. A problem with some compressors, such as scroll compressors, is that they may miswire during shutdown and run in the reverse direction as the pressure across the compressor becomes equal. Under these conditions, some types of oil pumps will not function properly, and damage may occur due to improper lubrication. Oil pumps that function properly in reverse rotation are typically relatively complex and expensive.

Positive displacement pumps are driven by a shaft through slots in the eccentric rotor and cooperating pins. The pins cooperating with the slots position the eccentric rotor appropriately relative to the fluid passage for any direction of rotation so that oil can be pumped in one direction.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a positive displacement oil pump having a small number of members and having a low cost and high reliability.

Another object of the present invention is to provide a positive displacement oil pump suitable for horizontal and vertical compressors.

Another object of the present invention is to provide a pump that pumps a fluid in one direction according to the direction of rotation of the shaft. These and other objects which will become apparent hereinafter are achieved according to the technology of the present invention.

Basically the eccentric rotor is housed on the shaft end and surrounded by a pivot ring that pivots about a fixed point. The end caps cooperate with the shaft end to hold the rotor and pivot ring in place. A pin secured to the shaft end cooperates with a slot in the rotor to position the rotor in line with the direction of rotation of the shaft.

Referring to the drawings, reference numeral 12 generally denotes an axis of a fluid machine such as a scroll compressor. 1 to 3, the shaft 12 has a cylindrical reduced diameter shaft end separated from the first portion by a first portion 12-1 and a shoulder 12-2. (12-3) is provided. The drive pin 14 is received in the bore of the shaft 12 and extends axially from the shoulder 12-2. The grooves 12 - 4 and 12 - 5 extending in the axial direction are formed on the surface of the axial end 12 - 3 to form an oil supply structure. Oil is supplied along the direction of rotation of the shaft 12 via radial passages 12-8 and 12-9 to the bore 12-6 provided with the threaded portion 12-7 (not shown). It is supplied to bearings that require lubrication. Reference numeral AA denotes the bore 12 - 6 and the central axis of the shaft 12 .

Referring to Figure 4, reference numeral 16 denotes a pivot ring. The pivot ring 16 has a bore 16-1 having a central axis denoted by point B, about which the pivot ring 16 pivots. The pivot ring 16 is joined by two straight segments in which two 180° semicircular segments centered on a central axis each indicated by points C, D are equal to the separation distance of points C and D. and a second bore 16-2 formed by the 5 and 6, the eccentric rotor 18 has an outer cylindrical surface centered on the point E and having a diameter approximately equal to the diameter of the semicircular portion of the bore 16-2. 18-1, whereby the rotor 18 is slide-fitted into the bore 16-2 and received in sealing contact. A circular bore 18-2 is formed in the rotor 18 and has a center point F spaced apart from the point E by a distance equal to the distance the points C and D are spaced apart. The rotor 18 has a diametric bore intersecting the bore 18-2 and formed of two segments 18-3 and 18-4 respectively. An actuation slot (18-5) is formed in the rotor (18) to receive the drive pin (14). 7, the end cap 20 has a central bore 20-1 and two bores 20-2, 20, respectively, aligned in grooves 12-4, 12-5. -3) is provided.

The assembled pump assembly 10 is best shown in FIGS. 8 and 9A. The axial end 12-3 is such that the drive pin 14 is positioned in the slot 18-5 and the bore 16-2 serves as a cylinder or piston chamber for the rotor 18 acting as a piston. It is surrounded by the rotor 18 received in the bore 16-2 of the pivot ring 16. The pivot ping 16 is properly pivotally fastened by bolts 24 to the pump end support 22 or the like. Optionally, a pin that is pressed into the support 22 with a sliding fit and extends into the bore 16-1 allows the ring 16 to pivotally rotate. End cap 20 is shafted by a dowel pin (not shown) or an assembly fixture to align bores 20-2, 20-3, respectively, with grooves 12-4, 12-5. (12) is appropriately positioned. The bolt 26 is received in the bore 20-1 and screwed into the threaded portion 12-7 of the bore 12-6 so that the rotor 18 and the pivot ring 16 are placed on the shoulder 12- 2) to be secured between the end cap 20 and to work together to form a suction and discharge chamber. The rotor 18 driving on the shaft end 12 - 3 is thus eccentric with respect to the abduction axis AA of the shaft 12 . This either eccentrics the central axis FF of the bore 18-2 of the rotor 18 from the central axis EE, as shown, or the shaft end 12-3 on which the rotor drives the axis ( 12) by eccentricity about the central axis AA by the same amount. Shaft 12 is machined such that shaft end 12-3 slides into bore 18-2 of rotor 18 . The shoulder 12-2 must be larger than the diameter of the bore 16-2 of the pivot ring 16 to seal the axial side of the pump assembly 10. If this is not the case, an appropriate ring or the like is attached to the shaft 12 to provide a seal as described above. The pivot ring 16 pivots on a bolt 24 that is rigidly attached to the pump housing. The ring 16 must be free to pivot because the rotor 18 is eccentric. Optionally, the ring 16 may be flattened on the two opposite outer sides as in the case of a sliding block so that it can reciprocate rather than pivot on the inside of the housing.

Referring to FIG. 8 corresponding to FIG. 9A, the oil from the reservoir 30 passes through the bore 20-3, the groove 12-5, and the bore 18-4, and the chamber 32 serves as a suction chamber. ) go inside. The oil in the chamber 34 serving as the discharge chamber is pumped into the bore 12-6 via the bore 18-3 and the bore 12-8, from which the bearing requiring lubrication. oil enters the

Referring to FIGS. 9a to 9d, which are illustrated by rotating the shaft 12 at intervals of 90°, the driving pin 14 is provided at one end of the slot 18-5, specifically, FIGS. 9a to 9d. It can be seen that it is located at the counterclockwise end of . When the shaft 12 rotates counterclockwise as shown, the drive pin 14 rotates with the shaft 12 while engaged with the counterclockwise end of the slot 18-5 while rotating the eccentric rotor 18 ) is driven counterclockwise. The central axis EE of the outer cylindrical surface 18-1 is eccentric with respect to the central axis FF of the bore 18-2 so that it is eventually coaxial with the central axis AA of the shaft 12 so that the rotor ( 18) effectively reciprocates within bore 16-2 with a double pumping operation provided by pivotal rotation of ring 16. In this case, 2 cycles of pumping are performed per rotation of the shaft 12 .

FIG. 9a shows a synchronous suction and discharge stroke as described with respect to FIG. The oil from the reservoir 30 is supplied to the chamber 32 through the groove 12-5 and the bore 18-4, and the oil in the chamber 34 is supplied to the bore 18-3 and the bore 12-8. ) through the bore (12-6) and from there it enters the bearing. Compared with FIG. 9a, FIG. 9b shows the completion of the suction and discharge process that occurred in FIG. 9a. The bores 18-3 and 18-4 are effectively blocked by the wall of the bore 16-2. When the shaft 12 and the rotor 18 further rotate counterclockwise from the position shown in Fig. 9b, the closed space defined by the chamber 32 and the bore 18-3 are communicated to communicate with the closed space. The oil in (32) is discharged to the member requiring lubrication through the bore 18-3, the bore 12-8, and the bore 12-6. Fig. 9c is similar to Fig. 9a except that chamber 32 and chamber 34, each serving as suction and discharge chambers, function in reverse. Although the suction and discharge process in FIG. 9c is different from that of FIG. 9a, FIG. 9d shows the completion of the suction and discharge process similar to FIG. 9b, and when further rotated counterclockwise, the closed space defined by the chamber 34 becomes bore ( 18-3) and discharged.

A major advantage of the present invention is that it is also actuated when the shaft 12 rotates in reverse. Fig. 10 shows the clockwise rotation position in the reverse direction. When shaft 12 rotates clockwise, pin 14 engages the clockwise end of slot 18-5, causing rotor 18 to rotate clockwise. Under the clockwise rotation state, compared to the counterclockwise rotation, the bore 20-2 and the groove 12-4 become a suction passage, and the bore 12-9 and the bore 12-6 are discharge passage. Also, the annular position of the member is different because the slots 18-5 are within a range of about 45 degrees. Specifically comparing FIGS. 9c and 10, the pin 14 and the bores 12-8 and 12-9 are located at the same position, but the bores 18-3 and 18-4 are shifted by 45°, Fig. 10 is in the initial stage of suction/discharge, approximately halfway between the cycle of Fig. 9d and the cycle of Fig. 9a. However, the pump assembly 10 functions the same no matter which direction it rotates.

While preferred embodiments of the present invention have been illustrated and described, those skilled in the art may alter otherwise. As an example, although the drawings specify the compressor as a horizontal type, the present invention is also suitable for a vertical type compressor. Moreover, the pump need not be supported by the reduced diameter portion of the shaft 12, but instead the support 22 can be expanded to function as the shoulder 12-2. In addition, the grooves 12-4 and 12-5 are provided with an oil supply structure such as an annular part formed in the support part 22 without directly communicating with the oil reservoir 30 via the bores 20-2 and 20-3 and It can be communicated to receive oil from a reservoir or an oil supply unit. Slots 18-5 do not need to be arcuate and may be replaced by notched ones. Accordingly, the scope of the present invention is limited only by the appended claims.