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FIELD OF THE INVENTION

The invention relates to an automotive vacuum pump. More particularly, the invention provides a customized sliding contact single vane rotary vacuum pump in which an oil supply passage is provided for flow of lubricating oil inside vane and/or vane slider thus reduces the peak torque, the pump internal chamber pressure and also results in better vacuum suction performance.

BACKGROUND OF THE INVENTION

Conventionally, a vacuum pump has been known, which includes: a housing including a substantially circular pump chamber; a rotor that rotates about a position eccentric with respect to a centre of the pump chamber; a vane or slider that is rotated by the rotor and that always partitions the pump chamber into a plurality of spaces; an oil supply passage that intermittently communicates with the pump chamber by the rotation of the rotor; and a gas passage that makes the pump chamber and an outer space communicate with each other when the oil supply passage communicates with the pump chamber by the rotation of the rotor, wherein the oil supply passage includes: a diameter direction oil supply hole provided at a shaft part of the rotor in a diameter direction thereof; and an axial direction oil supply groove that is provided in the housing to communicate with the pump chamber, and with which an opening of the diameter direction oil supply hole is made to intermittently over-lapping communicate by the rotation of the rotor, and wherein the gas passage is comprised of a gas groove whose one end is made to communicate with the outer space, the gas groove being formed on an outer peripheral surface of the rotor, and the other end of this gas groove is made to intermittently overlapping communicate with the axial direction oil supply groove by the rotation of the rotor.

For example, the "Taiho Kogyo Co. Ltd" disclosed a vane pump in U.S. Patent No. 8459973, a vane pump in which an oil supply passage through which lubricating oil flow is formed inside a rotor, and in which the lubricating oil is intermittently supplied in a pump chamber by a rotation of the rotor. Additionally, clogging of the groove is less likely to occur than the through-hole, thus enabling the reduction of the passage area of the groove as compared with a conventional diameter direction gas hole. Hence, the air is prevented from being sucked in the pump chamber from the gas passage as much as possible, thus enabling the prevention of the engine driving torque from increasing.

A related problem with aspect to the above example is that they are trying to reduce the pressure on vane by introducing passage groove to avoid air suction in pump chamber from gas chamber. However, a considerable amount of pressure is still on the vane due to oil present in the pump chamber which still results in requiring a high torque to drive the pump.

Similarly, the vane pump disclosed by US Patent No. 7628595, a gas vane pump wherein a lubricant is intermittently introduced into a housing during rotation of a rotor, through a supply passage formed through the housing and the rotor, and the relative position between the rotor having a diametric hole and the housing having a communication groove is determined such that when the rotor is at an angular position in the middle of a predetermined angular range relative to the housing and the hole is in communication with the groove, a point of contact between a vane movably held by the rotor and the inner circumferential surface of the housing is located at the lowest position of the inner circumferential surface. When the rotor is stopped within the predetermined angular range, the vane divides the remaining lubricant into two portions, which are discharged at different times, making it possible to reduce the load on the vane upon restarting the pump.

A related problem with aspect to the above example is that again they are trying to reduce the pressure on vane by positioning the vane in predetermined angular range inside the housing, so that the lubricant can be divided into two portions. However, in such case there has always been a chance of failure, as system will be dependent on the position of vane. Such a system needs a high degree of accuracy during manufacturing of component and assembling. Any discrepancy can lead to improper functioning which results in requiring a high torque to drive the pump.

The above mentioned mechanical vacuum pump used in current automotive application does not have such proof advantage of managed oil distribution inside the pump chamber to reduce the load on vane and power consumption to drive the pump. Therefore there is a need of an improved sliding contact single vane rotary vacuum pump having features for effectively reducing the pump internal pressure and increasing the pump vacuum efficiency with reducing the power consumption.

OBJECT OF THE INVENTION

The main object of this invention is to provide a sliding contact single vane rotary vacuum pump in which an oil supply passage is provided through for lubricating oil to flow inside, through and there through vane and/or vane slider.

Yet another object of the present invention is to provide a vane slider incorporated with oil passage, such as, but not limited to plurality of passage, vertical passage, horizontal passage or any combination thereof.

Yet another object of the present invention is to provide a vane incorporated with oil passage, such as, but not limited to a round hole, oblong hole, square hole or any other geometrical cavity.

Yet another object of the present invention is to customize a sliding contact single vane rotary vacuum pump, for utilizing less drive power and thereby improve the overall efficiency.

Yet another object of the present invention is to provide a sliding contact single vane rotary vacuum pump with improved vacuum suction performance.

SUMMARY OF THE INVENTION

The invention provides a sliding contact single vane rotary vacuum pump in which an oil supply passage such as but not limited to plurality of passages, vertical passage, horizontal passage or any combination thereof, through which a lubricating oil flows, formed inside vane and/or vane slider, which helps in reducing the torque of the pump during maximum vacuum condition and results in reduction of the power consumption of the vacuum pump which in-turn decreases the net load on the automotive engine, thus reduces the peak torque, the pump internal chamber pressure and also results in better vacuum suction performance. In the main embodiment of the present invention a sliding contact single vane rotary vacuum pump 100, comprising: an open housing 1, covering the rotary vacuum pump 100 with provisions for assembling an air exit nozzle 8 and an inlet oil filter 17; a rotor 5 assembled via a coupling 6 with into the said housing 1 having a radially movable vane 3; the vane 3 having vane slider 4A and 4B slidably supported inside a recess of the said rotor 5; an end plate 2 to cover the said housing 1 using plurality of bolts 15, incorporating an o-ring 20 in between them to avoid any leakage; wherein, a centre relief hole 21 or 24 is provided in vane slider 4A and 4B for oil distribution in the pump chamber with enhanced suction pressure of 39%; and the torque exertion by 2.86 - 7.63%.

In yet another embodiment of present invention, a vane and/or vane slider is incorporated with oil passage such as a round hole, oblong hole, square hole or any other geometrical cavity in centre which causes the relief in pressure level on the vane at the exit port by managing the oil flow distribution in the pump chamber.

In yet another embodiment of present invention, a vane and/or vane slider or vane is incorporated with oil passage such a round hole, oblong hole, square hole or any other geometrical cavity in centre which causes decrease in the required drive torque to operate the vacuum pump and results in power consumption of the pump by decrease in net load on an automotive engine.

In yet another embodiment of present invention, a vane and/or vane slider is incorporated with oil passage such as to a round hole, oblong hole, square hole or any other geometrical cavity in centre which enhance the vacuum suction performance and pump achieves required vacuum pressure in lesser time duration than the regular pump so it results in better vacuum suction performance.

BRIEF DESCRIPTION OF THE DRAWINGS

A complete understanding of the system and method of the present invention may be obtained by reference to the following drawings:

Fig. 1 is showing the torque comparison between conventional vacuum pump and one embodiment of present invention; Fig. 2 is showing the suction performance graph between conventional vacuum pump and one embodiment of present invention;

Fig. 3 is an exploded view of one of the embodiment of present invention;

Fig. 4 is a detailed view of vane with vane slider and rotor assembly inside the pump housing in one of the embodiment of present invention;

Fig. 5a, 5b, and 5c are detailed view of vane slider in one of the embodiment of present invention;

Fig. 6 is a detailed view of vane with vane slider and rotor assembly inside the pump housing with lubricating oil in one of the embodiment of present invention;

Fig. 7 is highlighting pressure exerted on vane with vane slider inside the pump housing by lubricating oil in one of the embodiment of present invention;

Fig. 8 is a sectional view of vane with vane slider in one of the embodiment of present invention; and

Fig. 9a, Fig. 9b and Fig. 9c are detailed view of another vane slider according to one of the embodiment of present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art.

Now referring to Figure 1, is a bar graph plotted for the speed (RPM) and torque. The graph provides torque comparison between conventional vacuum pump and the present invention having a single vane rotary vacuum pump with oil supply channel with relief hole in the centre. The results clearly show that more torque is generated for the same speed (RPM), clearly indicating a better performance over conventional system over wide range of RPM. Now referring to Figure 2, is a suction performance graph between conventional vacuum pump and the present invention having a single vane rotary vacuum pump with oil supply channel with relief hole in the centre. A graph is plotted between absolute pressure and time required to achieve the same. For consideration a set value of 33.3 kPa at 8.5 seconds is tested. During performance it is achieved by present invention in 5.18 seconds, whereas in conventional pump it is achieved in 6.6 seconds.

Now referring to Figure 3, is an exploded view of present invention is illustrated. The vacuum pump 100 comprises of an open housing 1 inside which a coupling 6, a rotor 5, a vane 3 and vane slider 4A and 4B are secured using an end plate 2 and an o-ring 20 is placed in between them to avoid any leakage. Further open housing 1 and end plate 2 are coupled together using plurality of bolts 15. Coupling 6 and rotor 5 are coupled by mean of a locking cap 7 and screw or bolt 16. The vane 3 having vane slider 4A and 4B are slidably supported inside a recess of the rotor 5. On the open side of housing 1, a sealing o-ring 12 with external circlips 13 and 14 is provided for seal against the engine cylinder head. Further an air exit nozzle 8 is mounted with open housing 1 and a check valve arrangement made up of a valve o-ring 11, valve cover 10 and a rubber diaphragm 9 is employed inside to keep it one way. An inlet oil filter 17 is mounted on the open housing top 1 facing the engine side and is secured by using filter wire mesh 18 and circular washer 19.

Now referring to Figure 4, is a detailed view of vane 3 with vane slider 4A and 4B and rotor 5 assemblies inside the pump open housing 1 in one of the embodiment of present invention. The vane 3 having vane slider 4A and 4B are slidably supported inside a recess of the rotor 5. The arrangement of slider 4A and 4B is such that they are always in contact with internal circumference of the pump open housing 1.

Figure 5a, Figure 5b and Figure 5c are detailed view of vane slider 4A according to one of the embodiments of present invention. Figure 5a is top view of vane slider 4A showing flat end which insert into vane recess and curved end. Figure 5b is front view of vane slider 4A showing a centre relief hole 21 of diameter 1.5 mm. Figure 5c is a sectional view of vane slider 4A showing through depth of centre relief hole 21.

Figure 6 is a detailed view vane 3 with vane slider 4A and 4B and rotor 5 assemblies inside the pump housing 1 with lubricating oil inside. The vane 3 along with vane slider 4A and 4B helps in distribution of lubricating oil inside the open housing 1 and the centre relief hole 21 of vane slider 4A and 4B further reduces the oil pressure exerted on vane 3 thus helps in reducing the torque requirement for driving the pump and increases the pump vacuum efficiency.

Figure 7 highlights pressure exerted on vane 3 with vane slider 4A and 4B inside the pump housing by lubricating oil in one of the embodiment of present invention. The centre relief hole 21 of vane slider 4A and 4B provides relief in pressure level on the vane 3 at the exit port by managing the oil flow distribution inside the pump open housing 1. This centre relief hole 21 in vane slider 4A and 4B causes decrease in the required drive torque to operate the vacuum pump 100 which results in lesser power consumption of the vacuum pump 100 by decreasing net load on automotive engine. Also the vacuum suction performance is increased and vacuum pump 100 achieves required vacuum pressure in lesser time duration which results in better vacuum suction performance.

Figure 8 is a sectional view of vane 3 and vane slider 4A along with passage way 22 and 23 in one of the embodiment of present invention. As the oil and air mixture causes the opposite pressure forces on the vane 3 at exit port of the vacuum pump 100 which results in increase in the required drive torque to operate the vacuum pump. Centre relief hole 21 in vane slider 4A helps in oil flow distribution in the pump chamber and reduces the pump internal pressure and increases the pump vacuum efficiency. The passage way 22 and 23 along with centre relief hole 21 in vane slider 4A provides a channel which reduces the lubricant pressure from both the surfaces (upper and lower) of vane 3 thus always maintains a steady state while operation.

Figure 9a, Figure 9b and Figure 9c are detailed view of another vane slider 4A in one of the embodiment of present invention. Figure 9a is side view of vane slider 4A showing flat end which inserts into vane recess and a curved end with plurality of grooves which is in contact with internal surface of open housing 1, these slots enhance the distribution of lubricating oil while vacuum pump 100 is under operation. Figure 9b is bottom view of vane slider 4A showing a centre relief hole 24 of diameter 1.5 mm in its centre. Figure 9c is a sectional view of vane slider 4A showing through depth of centre relief hole 24. Figure 9d is a side view of vane slider 4A showing plurality of grooves 25 over the curved surface of vane slider 4A. Although the invention has been illustrated and described with respect to one or more implementations, equivalent alterations and modifications will occur. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.

Many modifications and other embodiments of the invention set forth herein will readily occur to one skilled in the art to which the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.