JP2577065Y2 - Oil pump - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to an oil pump,
More particularly, the present invention relates to an inscribed oil pump used for a lubricating oil supply system of an automobile engine.

[0002]

2. Description of the Related Art A conventional oil pump of this type is disclosed in Japanese Utility Model Laid-Open Publication No. Sho 59-175618 as FIGS. In this example, an inner gear and an outer gear whose inner teeth mesh with its outer teeth are rotatably housed in the body, and a crescent-shaped partitioning crescent is interposed in a range where the gears do not mesh with each other. This is an example of an oil pump in which an annular groove is provided on one or both of a side surface of an inner gear and a cover member facing the inner gear. That is, since a gap is inevitably interposed between the cover member and the side surface of the inner gear, air tends to enter from the outside through the gap, particularly on the suction chamber side, so that air enters the oil.

That is, in the above example, by providing an annular groove, oil leaking from the discharge chamber side through the gap is guided to the annular groove, while entering the pump chamber side from the suction side through the gap. The air to be pushed is prevented by the oil layer introduced into the annular groove.

[0004]

However, in the above-mentioned conventional example, although the annular groove is provided to prevent the invasion of air from the outside by the oil guided from the discharge chamber side into the annular groove, the annular groove is provided. Since the groove is provided over the entire circumference on the side surface of the inner gear and / or on the cover member side, the sliding contact surface in which a gap between the inner gear and the cover member is generated in the radial direction by the width of the groove is formed on the sliding contact surface. The sliding width becomes shorter. for that reason,
On the discharge chamber side where the oil pressure is kept high, there is a disadvantage that the amount of oil leakage increases, and there has been a problem that the amount of oil discharge decreases.

An object of the present invention is to solve such a conventional problem by preventing the inflow of air from the outside on the suction chamber side and suppressing the leakage of oil from the discharge chamber side to the outside. It is to provide an oil pump that can perform the operation.

[0006]

In order to achieve the above object, the present invention provides an inner rotor and an outer rotor having inner teeth meshing with outer teeth of the inner rotor at a meshing portion between a body and a cover member. With the rotation of the inner rotor, oil is introduced into the tooth space from the suction chamber during a period from immediately before the meshing portion to just before the closing portion, and between the tooth shape and the discharge chamber between immediately after the closing portion and immediately before the meshing portion. In the oil pump that discharges oil, air having a C-shape in the circumferential direction corresponding to a portion from immediately before the meshing portion of the cover member wall surface in contact with the side surface of the inner rotor to immediately after the closing portion via the suction chamber. A mixing prevention groove is provided.

[0007]

According to the present invention, oil is received from the discharge chamber near the end of the C-shaped air entrapment prevention groove immediately before the meshing portion and the end immediately after the closing portion, which is associated with the discharge chamber, and this oil is received. By guiding the received oil to the C-shaped annular portion of the air entrapment prevention groove provided along the suction chamber side, it is possible to prevent air from entering from the suction chamber side, and to cover the inner rotor side surface. The leakage of oil can be suppressed because the air mixing preventing groove is not formed in the most part of the member wall surface related to the discharge chamber.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

1 to 3 show one embodiment of the present invention. In FIG. 1, 1 is a pump body, 2 is provided on the body 1 side, and a pump chamber 5 rotatably accommodates an outer rotor 3 and an inner rotor 4 as a drive gear meshing with its internal teeth. The communicating suction chamber 6 is a discharge chamber. Reference numeral 7 denotes a meshing portion for separating the suction chamber 5 and the discharge chamber 6 from each other, and in this portion, the outer rotor 3 and the inner rotor 4 are maintained in a meshing state. Reference numeral 8 denotes a closing portion. In this case, the oil introduced into the volume chamber 9 in the suction chamber 5 is kept in a closed state between the oil and the corresponding closing wall on the cover member 10 side. FIG. 2 shows the cover member 1.
Reference numeral 0 denotes the drive shaft through hole, as viewed from the body 1 side. As shown in FIG. 3, the inner rotor 4 is fitted to the drive shaft 12, and in this example, the drive shaft 12 is formed integrally with the crankshaft 13 on the engine side.

In FIGS. 2 and 3, reference numeral 14 denotes an air mixing preventing groove according to the present invention. That is, as shown in these figures, the air mixing preventing groove 14 is formed in a C shape along the wall surface of the cover member 10 facing the side surface of the inner rotor 4 in this embodiment. Each circumferential end 14A of the C-shaped air entrapment prevention groove 14 is kept extended to a position related to the discharge chamber 6, while a main portion of the groove ( 14B is formed along the suction chamber 5 from the meshing portion 7 to the closing portion 8. In FIG. 3,
Reference numeral 15 denotes an oil seal.

Next, the operation of the air mixing preventing groove 14 in the oil pump configured as described above will be described.

In FIG. 1, the inner rotor 4 is rotated in the counterclockwise direction indicated by the arrow P by the drive shaft 12, and accordingly, the volume chamber 9 immediately after the meshing portion 7 is rotated.
The oil is introduced from the suction chamber 5 side into the suction chamber 5. At this time, air tends to be mixed into the oil from the outside along the drive shaft 12 through a gap between the side surface of the inner rotor 4 and the opposing surface of the cover member 10. However, one discharge chamber 6
Since the oil pressure of the discharged oil is increased on the side, the oil tends to leak through the above-mentioned gap, and this leaking oil is radially discharged from the discharge chamber 6 as shown in FIG. It is easy to be guided to both end portions 14A of the air mixing prevention groove 14 having the shortest distance.

The oil thus guided to the groove 14 wraps around the annular portion 14B of the groove 14 to form an oil film layer between itself and the side wall of the inner rotor 4, thereby sealing the gap in the radial direction. This can prevent air from entering the suction chamber from the outside. On the discharge chamber 6 side, the air entrapment prevention groove 14 is formed on a radial wall surface from the through hole 11 of the cover member 10 to the discharge chamber 6 except immediately before the engagement portion 7 and immediately after the closing portion 8. Due to the absence, oil leakage from this portion can be sufficiently suppressed.

In the above-described embodiment, the case of the trochoid type internal oil pump has been described. However, application of the present invention is not limited to this, and it has a crescent as described in the prior art. It goes without saying that the present invention can be similarly applied to an internal gear type pump.

[0015]

As described above, according to the present invention, the circumference corresponding to the portion from immediately before the meshing portion of the wall surface of the cover member in contact with the side surface of the inner rotor to immediately after the closing portion via the suction chamber. A C-shaped air mixing prevention groove is provided in the direction, so that air is prevented from being mixed in from the outside through the above-mentioned gap on the suction chamber side, while one discharge side is formed through the above-mentioned gap. Oil can be prevented from leaking to the outside.

[Brief description of the drawings]

FIG. 1 is a side view showing the configuration of an embodiment of the present invention as viewed from the inside of a body.

FIG. 2 is a side view showing the configuration of a cover member for the body shown in FIG. 1 as viewed from the inside.

FIG. 3 is a sectional view of the oil pump according to the present invention, taken along line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 3 Outer rotor 4 Inner rotor 5 Suction chamber 6 Discharge chamber 7 Engaging part 8 Closed part 9 Volume chamber 10 Cover member 12 Drive shaft 14 Air mixing prevention groove 14A End part 14B Ring part

Claims (1)

(57) [Scope of request for utility model registration] An inner rotor and an outer rotor having internal teeth meshing with external teeth of the inner rotor at a meshing portion are housed between a body and a cover member, and the inner rotor rotates from the meshing portion to immediately before a closing portion. An oil pump that introduces oil from the suction chamber to the tooth profile from the suction chamber until the oil is discharged from the tooth profile to the discharge chamber from immediately after the closing portion to immediately before the meshing portion, wherein the oil pump contacts the side surface of the inner rotor. An oil pump provided with a C-shaped air entrapment prevention groove in a circumferential direction corresponding to a portion immediately before the meshing portion of the cover member wall surface and immediately after the closing portion via the suction chamber.