JP7832464B2 - vane pump - Google Patents

Description

This invention relates to a vane pump for supplying cooling oil or lubricating oil to various types of machinery.

Vane pumps are used as oil sources in cooling and lubrication systems, supplying cooling oil to motors for vehicle drive systems, lubricating oil to bearings, and lubricating oil to gears such as reduction gears and differential gears.

A vane pump comprises a cam ring, a rotor located inside the cam ring and rotated by a power source, and adjacent vanes housed in multiple radially arranged slits on the outer surface of the rotor, contacting the inner surface of the cam ring to form multiple pump chambers inside the ring.

As shown in Patent Document 1, vane pumps have a problem where, when the pump chamber, which has drawn in hydraulic fluid from the intake port, connects to the discharge port, the pressure inside the pump chamber rises sharply, crushing air bubbles mixed in the hydraulic fluid. This shock generates noise and erosion. Patent Document 1 proposes a configuration in which a flow path is formed in the vane to release the pressure from the pump chamber to the back pressure chamber. Patent Document 1 states that this eliminates compression and provides a high shock reduction effect.

Patent Document 2 proposes a configuration in which a vane chamber drain passage is formed in the transition region where the vane chamber (pump chamber) transitions from the discharge region to the suction region, connecting the vane chamber to the outside of the vane pump. This configuration prevents compressed air, along with the working fluid, from being carried to the suction region, ensuring smooth suction of the working fluid in the suction region and maintaining the suction performance of the vane pump.

Japanese Patent Publication No. 2021-148113 Patent No. 5597530

However, when the vane pump rotates, because the hydraulic fluid is heavier than the air bubbles, centrifugal force causes the hydraulic fluid to accumulate on the cam ring side (outside) of the pump chamber, and the air bubbles to accumulate on the rotor side (inside: outer surface of the rotor) of the pump chamber. In the configuration of Patent Document 1, since the flow path is provided in the vane, there is a problem in that it is difficult to discharge the air accumulated inside the vane opening (front recess 61) when there is a large amount of air in the hydraulic fluid.

In the configuration described in Patent Document 2, the hydraulic fluid mixed with air bubbles is discharged in the transition region where it transitions from the discharge region to the suction region. Therefore, it is not possible to eliminate noise and erosion during discharge. Furthermore, additional drain piping is required to guide the oil discharged from the vane chamber drain passage, and since the discharged amount is supplied from the pump chamber of the adjacent discharge process, this can lead to pressure leakage and a decrease in volumetric efficiency.

In view of these problems, the present invention aims to provide a vane pump that efficiently discharges mixed-in air without causing performance degradation due to pressure leakage.

To solve the above problems, a typical configuration of the vane pump according to the present invention is a vane pump having a cam ring, a rotor rotatably arranged in the internal space of the cam ring and having a plurality of slits formed on its outer circumference, adjacent vanes arranged to move back and forth in the plurality of slits so as to abut the inner circumference of the cam ring and to form a plurality of pump chambers, two side plates sandwiching both sides of the rotor, and an intake port and an exhaust port formed in the side plates, wherein the rotor has one or more air storage holes that penetrate both sides of the rotor between adjacent vanes, and the two side plates have air guide grooves that connect the pump chamber and the air storage holes downstream of the intake port , and the air storage holes communicate with the exhaust port.

Furthermore, it is preferable that the two side plates have pressure release grooves formed on the upstream side of the intake port, connecting the pump chamber and the air storage hole.

The discharge port is preferably formed with an expansion section that communicates with the air storage hole, and this expansion section is positioned so that it communicates with the air storage hole after the pump chamber has communicated with the discharge port.

According to the present invention, it is possible to provide a vane pump that efficiently discharges mixed-in air without causing performance degradation due to pressure leakage.

This is an exploded perspective view illustrating the configuration of the vane pump according to this embodiment. This is a diagram illustrating each component. This diagram illustrates the function of the air storage hole, air guide groove, and pressure release groove.

Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely illustrative to facilitate understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and the drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

Figure 1 is an exploded perspective view illustrating the configuration of the vane pump 100 according to this embodiment. The vane pump 100 shown in Figure 1 is used in automobiles as an oil supply source for parts requiring cooling or lubrication. The vane pump 100 has a cam ring 110 with an internal space and a cylindrical rotor 120 rotatably arranged within the internal space of the cam ring 110.

A shaft 130 is inserted into the center of the rotor 120, and the rotor 120 is coupled to the shaft 130 so that it can rotate integrally with the shaft in the circumferential direction. Multiple radially formed slits 122 are arranged at equal intervals in the circumferential direction on the outer surface of the rotor 120. A vane 140 is housed in each slit 122 so as to be able to move radially back and forth. The vane 140 protrudes and slides against the inner circumferential surface of the cam ring 110.

The cam ring 110 has a roughly elliptical internal space 112 when viewed from the side. The internal space 112 is continuously formed with portions close to the rotor 120 and portions spaced away from the rotor 120 at 180-degree intervals in the rotational direction of the rotor 120. Both axial ends of the internal space 112 are covered by the first side plate 200 and the second side plate 300. Therefore, when the rotor 120 rotates, the vanes 140 abut against the inner circumferential surface of the cam ring 110 due to centrifugal force, forming multiple pump chambers 150 separated by adjacent pairs of vanes 140, the outer circumferential surface of the rotor 120, the inner circumferential surface of the cam ring 110, and the first and second side plates 200 and 300. The first and second side plates 200 and 300 have holes 202 and 302 through which the shaft 130 passes.

Figure 2 illustrates each component; Figure 2(a) is a front view showing the sliding surface of the first side plate 200, (b) is a front view of the cam ring 110 and rotor 120, and (c) is a rear view showing the sliding surface of the second side plate 300. Note that Figure 2(c) is shown inverted to show the sliding surface on which the rotor 120 slides.

As shown in Figure 2(a), the first side plate 200 is a disc-shaped member and has two intake ports 210 and two discharge ports 220 that straddle the major axis of the ellipse of the internal space. Each of the two intake ports 210 is connected to an oil passage that is connected to an oil reservoir (not shown). The two discharge ports 220 supply cooling oil to the vehicle drive motor, lubricating oil to the bearings in the vehicle, and lubricating oil to gears such as the reduction gear and differential gears of the wheels, via oil passages (not shown).

As shown in Figures 2(b) and 1, the cam ring 110 has intake grooves 114 formed at positions corresponding to the intake port 210. Since the intake grooves 114 are formed on both sides of the first side plate 200 and the second side plate 300, a total of four grooves are formed.

As shown in Figure 2(c), the second side plate 300 is a disc-shaped member. It has two notched intake ports 310 at positions corresponding to the intake ports 210 of the first side plate 200. Furthermore, the sliding surface shown in Figure 2(c) has two recesses 320 at positions corresponding to the discharge ports 220 of the first side plate 200. In other words, the second side plate 300 has no discharge ports; the hydraulic fluid is discharged from the discharge ports 220 of the first side plate 200.

The basic operation of the vane pump 100 will be explained. The rotor 120 rotates so that the vanes 140 face from the inlet ports 210 and 310 towards the discharge port 220. In other words, the inlet ports 210 and 310 are upstream of the rotor 120's rotation, and the discharge port 220 is downstream. As the rotor 120 rotates, oil is introduced from the inlet ports 210 and 310 as the volume of the pump chamber 150 increases at the inlet ports 210 and 310. Subsequently, as the volume of the pump chamber 150 decreases at the discharge port 220, oil is discharged from the discharge port 220.

Here, the rotor 120 has one or more air reservoir holes 124 that penetrate both sides of the rotor 120 between adjacent vanes 140 (pump chambers 150). While the diagram shows air reservoir holes 124 between all vanes 140 (all pump chambers 150), the number of air reservoir holes 124 can be adjusted as needed. For example, there could be only one in total, two at 180-degree intervals, or every other hole.

In other words, although the air reservoir hole 124 opens to the side of the rotor 120, the side of the rotor 120 is a sliding surface with the first side plate 200 or the second side plate 300, so hydraulic fluid cannot actively flow in. Therefore, the first side plate 200 has a pressure release groove 232 and an air guide groove 234 that connect the pump chamber 150 and the air reservoir hole 124. The pressure release groove 232 is formed upstream of the intake port 210, and the air guide groove 234 is formed downstream of the intake port 210. Similarly, the second side plate 300 has a pressure release groove 332 formed upstream of the intake port 310, and an air guide groove 334 formed downstream of the intake port 310.

At the discharge port 220, an expanded portion 222 is formed, protruding inward from the downstream end of the discharge port 220 and communicating with the air storage hole 124. Similarly, at the recess 320, an expanded portion 322 is formed, protruding inward from the downstream end of the recess 320 and communicating with the air storage hole 124. The expanded portions 222 and 322 are located in corresponding positions (opposite positions). That is, the expanded portions 222 and 322 are formed in a position where they communicate with the air storage hole 124 after the pump chamber 150 has communicated with the discharge port 220. Alternatively, the discharge ports 220 and 320 could simply be widened inward to communicate with (overlap with) the air storage hole 124.

Figure 3 illustrates the operation of the air reservoir hole 124, pressure release grooves 232, 332, and air guide grooves 234, 334. In Figures 3(a), (c), and (e), the hatching on the air reservoir hole 124, pressure release grooves 232, 332, and air guide grooves 234, 334 is not to indicate a cross-section, but to make them easier to see. In Figures 3(b), (d), and (f), the hatching on the cam ring 110, rotor 120, first side plate 200, and second side plate 300 indicates a cross-section.

Figure 3(a) is a diagram illustrating the suction process, and Figure 3(b) is a cross-sectional view taken along line P-P in Figure 3(a). The suction process is the process in which the pump chamber 150 is located between the minor axis and major axis of the ellipse within the internal space 112 of the cam ring 110.

First, the air reservoir 124 has a relatively high pressure due to the pressure from the preceding discharge process (discharge pressure). As the rotor 120 rotates to the left in the diagram, the pressure release grooves 232 and 332 are formed upstream of the intake port. Therefore, the pump chamber 150 communicates with the air reservoir 124 via the pressure release grooves 232 and 332, and subsequently, the pump chamber 150 communicates with the intake port 210.

As the volume of the pump chamber 150 increases, the pressure decreases (suction pressure: negative pressure), drawing in hydraulic fluid through the suction port 210. At this point, it is assumed that air bubbles are mixed into the hydraulic fluid drawn in through the suction port 210. Since the suction pressure is lower than the pressure inside the air storage hole 124 (discharge pressure), the pressure inside the air storage hole 124 also decreases, as shown in Figure 3(b). When the pump chamber 150 passes through the pressure release grooves 232 and 332, communication between the pump chamber 150 and the air storage hole 124 is lost.

Figure 3(c) is a diagram illustrating the compression stroke, and Figure 3(d) is a cross-sectional view taken along the line Q-Q in Figure 3(c). The compression stroke is the process in which the pump chamber 150 moves from the major axis to the minor axis of the ellipse within the internal space 112 of the cam ring 110, until it reaches the discharge port 220.

As the rotor 120 rotates, the pump chamber 150 moves past the long axis of the internal space 112. This reduces the volume of the pump chamber 150, increasing the pressure inside (compression pressure). At this time, centrifugal force causes hydraulic fluid to accumulate on the cam ring 110 side (outside) of the pump chamber 150, while air bubbles accumulate on the rotor 120 side (inside: outer surface of the rotor). When the pump chamber 150 approaches the air guide grooves 234 and 334, the pump chamber 150 and the air storage hole 124 communicate via the air guide grooves 234 and 334. Because the pump chamber 150 is under high compression pressure and the air storage hole 124 is under low suction pressure, as shown in Figure 3(d), the hydraulic fluid mixed with air bubbles that has convected near the outer surface of the rotor 120 flows into the air storage hole 124. The inside of the air storage hole 124 becomes compressed.

Figure 3(e) illustrates the discharge process, and Figure 3(f) is a cross-sectional view taken along line S-S in Figure 3(e). The discharge process is the process while the pump chamber 150 is in communication with the discharge port 220.

The discharge pressure is lower than the compression pressure. When the pump chamber 150 and the discharge port 220 are connected, the hydraulic fluid in the pump chamber 150 is discharged from the discharge port 220. At this time, the pressure in the air reservoir 124 is also the compression pressure. Therefore, the hydraulic fluid mixed with air bubbles inside the air reservoir 124 is discharged from the discharge port 220 due to the pressure difference and the discharge flow, as shown in Figure 3(f).

As explained above, even if air bubbles enter the hydraulic fluid from the intake port 210, they can be temporarily stored in the air storage hole 124 and then discharged from the discharge port 220. Since the air flows into the air storage hole 124 from the rotor 120 side of the pump chamber 150 (the outer circumferential surface of the rotor 120), compared to Patent Document 1, air bubbles do not accumulate on the outer circumferential surface of the rotor 120. Therefore, air can be discharged efficiently. Furthermore, compared to Patent Document 2, no additional drain piping is required, and since there is no configuration for further discharge after discharge, performance degradation due to pressure leakage is avoided. Therefore, a vane pump can be provided that efficiently discharges mixed air without causing performance degradation due to pressure leakage.

While preferred embodiments of the present invention have been described above with reference to the attached drawings, it goes without saying that the present invention is not limited to these examples. Those skilled in the art will understand that various modifications and alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention.

This invention can be used as a vane pump to supply cooling oil or lubricating oil to various types of machinery.

100…Vane pump, 110…Cam ring, 112…Internal space, 114…Intake groove, 120…Rotor, 122…Slit, 124…Air storage hole, 130…Shaft, 140…Vane, 150…Pump chamber, 200…First side plate, 202…Hole, 210…Intake port, 220…Discharge port, 222…Expansion section, 232…Pressure release groove, 234…Air guide groove, 300…Second side plate, 302…Hole, 310…Intake port, 320…Recess, 322…Expansion section, 332…Pressure release groove, 334…Air guide groove

Claims (3)

A vane pump that supplies cooling oil or lubricating oil to various machines,
Camring and,
A rotor is rotatably disposed within the internal space of the cam ring and has multiple slits formed on its outer surface,
Adjacent vanes are arranged to move back and forth in the plurality of slits so as to abut the inner circumferential surface of the cam ring, forming a plurality of pump chambers.
Two side plates sandwiching both sides of the rotor,
The side plate has an intake port and an outlet port formed therein,
A vane pump having,
The rotor has one or more air storage holes formed between adjacent vanes, penetrating both sides of the rotor.
The two side plates have air guide grooves formed on the downstream side of the intake port that connect the pump chamber and the air storage hole.
A vane pump characterized in that the air storage hole communicates with the discharge port. Furthermore, the vane pump according to claim 1 is characterized in that the two side plates have pressure release grooves formed on the upstream side of the intake port, connecting the pump chamber and the air storage hole. The discharge port has an expanded portion that communicates with the air storage hole,
The vane pump according to claim 1 or 2, characterized in that the expansion portion is formed at a position where the pump chamber communicates with the air storage hole after it has communicated with the discharge port.