JPH0542685U - Inscribed oil pump - Google Patents

Abstract

(57) [Abstract] [Purpose] Prevents air from entering the pump through the pump drive shaft through hole in the cover when oil is allowed to escape from the seal chamber to the cover side along the pump drive shaft. Providing an inscribed oil pump. [Structure] An escape passage 20 between the inner rotor 4 and the pump drive shaft 2 for allowing oil to escape to the cover 12 side along the axial direction.
Is provided, and the pump drive shaft 2 is
The gap 30 around the through hole 12A of the cover 12 through which
Inscribed oil pump with a small cross-sectional area.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an inscribed oil pump, and more particularly to an inscribed oil pump driven by a crankshaft as a pump for supplying lubricating oil for a vehicle engine.

[0002]

[Prior Art]

 As a conventional inscribed oil pump of this type, for example, there is one disclosed in Japanese Utility Model Laid-Open No. 61-132490. This is the outer peripheral surface of the pump drive shaft that extends from the crankshaft to the pump housing side to fit the inner rotor and has parallel chamfers for transmitting the driving force from the crankshaft. The inner peripheral surface of the inner rotor fitting hole to be fitted is made larger in diameter to create a gap between the inner rotor fitting hole and the oil that leaks from the pump housing to the outside through the gap on the opposite side to the housing. It is designed to be returned to the crankcase side of.

[0003]

[Problems to be solved by the device]

 However, in the internal type oil pump configured as in the above-mentioned conventional example, although the oil can be prevented from leaking from the pump housing over the seal to the outside due to the increase in the oil pressure in the seal chamber, There is a gap between the cover provided on the crankshaft side and the inner rotor, and there is no seal around the hole through which the pump drive shaft penetrates the cover. The structure is such that it can be returned to the crankcase side. On the other hand, in the pump, the volume chamber between the tooth tips changes with the rotation of the inner rotor, and negative pressure is generated on the suction side with the change, which causes a gap between the shaft hole of the cover and the gap between the cover and the inner rotor. A large amount of air may enter into the oil on the suction side after passing through, and as a result, there is a problem that abnormal noise is generated in the engine HVLA (Hydraulic Valve Lash adjuster) there were.

The object of the present invention is to pay attention to such a conventional problem and to allow the oil in the seal chamber to escape along the pump drive shaft to prevent the oil from leaking to the outside. An object of the present invention is to provide an inscribed oil pump which can prevent air from entering through the shaft through hole and can stably feed oil without air being mixed.

[0005]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention accommodates an inner rotor fitted to a pump drive shaft extending from a crankshaft and an outer rotor inscribed in the inner rotor in a pump housing, and covering the pump housing. In the internal oil pump through which the pump drive shaft penetrates, an escape passage is provided between the inner rotor and the pump drive shaft along the axial direction for releasing oil to the cover side, and a cross-sectional area of the escape passage is The cross-sectional area of the gap around the through hole of the cover through which the pump drive shaft penetrates is reduced.

[0006]

[Action]

 According to the present invention, the cross-sectional area of the clearance around the through hole penetrating the cover is made smaller than the cross-sectional area of the relief passage provided in the fitting portion of the inner rotor and the pump drive shaft. The flow of oil introduced into the pump is throttled in front of the cover, so that the gap around the through hole is constantly filled with oil, so that air enters the oil inside the pump through the through hole. Can be prevented.

[0007]

【Example】

 Embodiments of the present invention will be specifically described below with reference to the drawings.

1 and 2 show an embodiment of the present invention. In these drawings, 1 is a crank shaft, 2 is a pump drive shaft extending from the crank shaft 1 to the oil pump 3 side, 4 is an inner rotor fitted to the pump drive shaft 2 and driven by the pump drive shaft 2. Reference numeral 5 denotes an outer rotor 5 having a larger number of inner teeth 5A than the outer teeth 4A of the inner rotor 4, and both tooth types mesh with each other at a meshing portion, and a pump housing 6 accommodates the outer rotor 5 rotatably. The pump housing 6 is provided with a suction chamber 8 into which oil is introduced from the suction port 7 and a discharge chamber 10 into which oil discharged from the pump 3 is guided to the discharge port 9. Further, in FIG. 2, 11 is an oil seal provided around the pump drive shaft 2 penetrating the pump housing 6, 12 is a cover member attached to the crank chamber 13 side of the oil pump 3, and thus the cover member 12 and the pump housing are provided. The inner rotor 4 is rotatably held together with the outer rotor 5 between the inner rotor 4 and the pump housing chamber 14 provided in the housing 6.

By the way, the pump drive shaft 2 of this embodiment is formed with drive transmission surfaces 2A which are parallel to each other in order to transmit a driving force to the inner rotor 4, and the fitting hole 4A of the inner rotor 4 is also formed. Although it is formed in a shape corresponding to the drive shaft 2, the oil introduced into the seal chamber 15 is released between the pump drive shaft 2 and the inner rotor fitting hole 4A to the crank chamber 13 side. A gap 20 is provided. A gap 30 is also provided between the through hole 12A of the cover 12 through which the pump drive shaft 2 penetrates and the outer peripheral portion of the pump drive shaft 2, and the gap 30 is formed sufficiently narrower than the gap 20 described above. ..

Next, the operation of the inscribed oil pump 3 thus configured will be described.

The inner rotor 4 rotates in the same direction as the drive shaft 2 rotates in the arrow direction by the crankshaft 1. Thus, the outer rotor 5 is interlocked with the rotation of the inner rotor 4, and the oil is guided from the suction chamber 8 to the volume chamber 16 formed between the two tooth types. Then, the oil trapped in the volume chamber 16 is delivered to the discharge chamber 10, and the delivered oil is distributed to each part from a main gallery (not shown) of the lubricating oil supply system.

By the way, in this embodiment, since the gap 30 is provided between the fitting hole 4A of the inner rotor 4 and the pump drive shaft 2, the oil leaked through the wall of the pump housing chamber 14 into the seal chamber 15 Can be escaped from the gap 30 to the crank chamber 13 side through the through hole 12A of the cover 12. Moreover, due to the negative pressure generated by the expansion of the volume chamber 16 on the suction chamber 8 side, air is guided to the volume chamber 16 from the through hole 12 of the cover 12 through the gap between the cover 12 and the inner rotor 4. Although there is a tendency for this to occur, since the gap 30 around the through hole 12 is formed sufficiently narrower than the gap 20 around the inner rotor fitting hole 4A, the oil introduced into the gap 20 stays in front of the other gap 30. Therefore, since the gap 30 is always filled with oil, it is possible to prevent air from entering from the crank chamber 13 side through the gap 30.

In the present embodiment, in order to allow the oil to escape from the seal chamber 15 to the crank chamber 13 side, the gap 20 is formed in a substantially circumferential shape between the pump drive shaft 2 and the inner rotor fitting hole 4A. The oil escape path is not limited to the shape of such a gap, and the present invention is also applicable to a structure in which an axial oil escape groove is formed in the pump drive shaft 2 or the inner rotor fitting hole 4A. The same effect can be obtained in this case by making the total cross-sectional area of the gap 20 formed around the through hole 12A of the cover sufficiently smaller than the total cross-sectional area of the oil escape groove.

[0014]

[Effect of the device]

 As described above, according to the present invention, an escape passage is provided between the inner rotor and the pump drive shaft along the axial direction to allow the oil to escape to the cover side, and the pump is constructed from the cross-sectional area of the escape passage. Since the cross-sectional area of the gap around the through hole of the cover through which the drive shaft penetrates is made small, the oil that escapes from the seal chamber to the crank chamber side along the escape path around the fitting hole of the inner rotor is It becomes a shape that is squeezed just before passing through the clearance around the through hole, and therefore, due to the negative pressure generated on the suction side of the pump, the air from the clearance around the through hole of the cover causes the clearance between the cover and the inner rotor. It is possible to prevent inconveniences such as invading the oil in the pump via the engine, causing abnormal noise in the HVLA of the engine, and lowering the hydraulic pressure.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

 2 Pump drive shaft 2A Drive transmission surface 3 Oil pump 4 Inner rotor 4A Fitting hole 5 Outer rotor 6 Pump housing 8 Suction chamber 10 Discharge chamber 11 Oil seal 12 Cover 13 Crank chamber 14 Pump accommodating chamber 15 Seal chamber 16 Volume chamber 20 Gap 30 Gap

Claims (1)

[Scope of utility model registration request] 1. An inner rotor fitted to a pump drive shaft extending from a crankshaft and an outer rotor inscribed in the inner rotor are housed in a pump housing, and the pump drive shaft penetrates a cover of the pump housing. In the internal oil pump, a relief passage is provided between the inner rotor and the pump drive shaft along the axial direction to allow oil to escape to the cover side, and a cover through which the pump drive shaft penetrates due to a cross-sectional area of the relief passage. An inscribed oil pump characterized in that the cross-sectional area of the gap around the through hole is reduced.