JPH0452476Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an internal gear type oil pump for pumping lubricating oil and the like.

<Prior art> Internal gear type oil pumps, which are generally incorporated into automobile engines, discharge lubricating oil from a discharge port by rotating an externally toothed drive gear and an internally toothed driven gear that mesh with each other within the pump housing. Further, a part of this lubricating oil is released to a tank by a pressure relief valve inserted on the discharge passage, thereby supplying lubricating oil at a constant pressure to each part of the engine.

<Problems to be solved by the invention> However, in such conventional devices, although the lubricating oil flowing out from the relief valve has a large amount of energy, that energy is not fully utilized. Due to the arrangement of the relief valve, the lubricating oil that flows out from the relief valve collides with the wall and is collected into the oil pan, so the oil pan is filled with air bubbles and the lubricating oil containing these air bubbles is sucked into the pump. This caused noise and pulsation to occur.

<Means for Solving the Problems> The present invention has been made to solve the above-mentioned problems of the conventional art. A relief passage that is opened and closed by sliding of the valve member is formed in communication with the valve hole, and the relief passage extends in a tangential direction of the support hole and communicates with the suction port. This invention relates to an internal gear type oil pump.

<Function> Since the present invention has the above-mentioned configuration, the oil flowing out from the relief hole of the relief valve flows into the suction port from the tangential direction of the support hole, which simplifies the passage structure and eliminates the generation of air bubbles. Moreover, the bypass flow applies a pressing force to the driven gear toward the discharge port. This allows the driven gear to float above the support hole over its entire circumference, thereby preventing local wear due to contact with the pump housing.

<Examples> Examples of the present invention will be described below based on the drawings. In FIG. 1, 10 is a cylinder block of an automobile engine, 11 is a crankshaft, and 12 is a pump housing fixed to the cylinder block 10.

A lid member 13 is fixed to the pump housing 12, and the lid member 13 and the pump housing 12
In the gear chamber 14 formed between
Also, an internally toothed driven gear 16 that meshes with this drive gear 15 is housed.

A journal portion 17 is provided at one end of the drive gear 15.
The journal portion 17 is rotatably fitted into a bearing hole 18 formed in the pump housing 12. Further, as shown in FIG. 2, the driven gear 16 is rotatably fitted into a support hole 19 formed in the pump housing 12 eccentrically from the bearing hole 18. Said pump housing 1
2 and the lid member 13 are provided with suction ports 21, 22 and discharge ports 23, 2, respectively.
4 are formed spaced apart in the circumferential direction. And these suction ports 21, 22 and discharge port 2
A suction passage 26 and a discharge passage 27 are opened in each of 3 and 24, and oil in the oil pan is sucked through the suction passage 26, and oil is supplied to various parts of the engine through the discharge passage 27. There is.

The present invention is characterized in that a relief valve 30 having the following configuration is incorporated into the pump housing 12 in such an oil pump.
That is, a valve hole 31 is formed on the side of the support hole 19, and this valve hole 31 is connected to the discharge passage 27 via an introduction passage 32, and communicates with the suction ports 21 and 22 via a relief passage 33. has been done. The valve member 34 fitted in the valve hole 31 blocks the introduction passage 32 and the relief passage 33 when the discharge pressure is low, and when the discharge pressure exceeds the set pressure of the spring 36, the introduction passage 32 and the relief passage 33 are closed off. The passage 32 and the relief passage 33 are communicated with each other to control the discharge pressure.

Here, the relief passage 26 is the support hole 1
9, the bypass flow from the valve hole 31 flows out near the contact start point P1 of the driven gear 16, and flows upward with respect to the driven gear 16, that is, the discharge ports 23, 2.
It is designed to apply pressing force in four directions.

Further, this relief passage 33 is connected to the suction port 21,
22 and the suction passage 26, the oil in the suction passage 26 is supercharged using the energy of the oil flowing out from the relief passage 33.

In addition, in FIGS. 3 and 4, 38 is a groove formed in the support hole 19, and a groove 38 is formed in the support hole 19.
The oil flowing out from 3 penetrates to the end between the support hole 19 and the driven gear 16, and exerts a larger pushing up force on the driven gear 16.

In the above configuration, when the drive gear 15 is rotated by the crankshaft 11, the driven gear 16 that meshes with the drive gear 15 is rotated within the support hole 19. As a result, oil is sucked into the pump chamber between the drive gear 15 and the driven gear 16 through the suction ports 21 and 22, and the oil is sucked into the pump chamber between the drive gear 15 and the driven gear 16 through the suction ports 21 and 22, and
It is discharged from 24.

When performing such a pumping action, the discharge port 2
3 and 24 have high pressure, and the suction ports 21 and 2
2 becomes a low pressure, and the pressure difference becomes large especially at high speed rotation, and as a result, the driven gear 15 has a low pressure.
In the figure, a downward force is applied, and as a result, the driven gear 16 comes into local contact within the support hole 19, causing local wear of the support hole 19. In particular, since the pump housing 12 is made of aluminum, it is subject to significant wear.

However, in the oil pump of the present invention, when the discharge pressure rises above the set pressure of the spring 36 as the pump rotates at high speed, the valve member 34
It slides downward against the pressure, and releases a part of the discharged oil to the passage 33 to control the discharge pressure.

At the same time, the oil flowing out from this relief passage 33 in the tangential direction of the support hole 19 is rapidly flowing into the suction port 2.
1 and 22, and supercharges the oil in the suction passage 26. And as it is, driven gear 1
6 and is further introduced into the entire inner part via the groove 38. As a result, driven gear 1
A pushing force that cancels out the pressure difference acts on the support hole 6, and a minute clearance is secured between the support hole 19 and the driven gear 16, thereby preventing mechanical contact between the support hole 19 and the driven gear 16.

<Effects of the invention> As detailed above, the present invention forms a valve hole on the side of the support hole in which the valve member is slidably fitted into the pump housing, and the valve hole has the valve hole in which the valve member is slidably fitted. A relief passage that is opened and closed by sliding is formed in communication, and this relief passage is extended in the tangential direction of the support hole and communicated with the suction port, so that the driven gear is affected by the action of oil flowing out from the relief passage. This has the advantage of being able to apply a pressing force in the direction toward the discharge port, thereby preventing local contact between the driven gear and the pump housing and local wear associated therewith.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view showing the internal gear type oil pump of the present invention installed on the cylinder block of an automobile engine, and FIG. − cross-sectional view along the line;
FIG. 3 is a partially enlarged sectional view showing an enlarged suction port portion, and FIG. 4 is a sectional view taken along the - line in FIG. 3.

Claims (1)

[Scope of utility model registration request] An oil pump that sucks fluid through a suction port formed in an inner peripheral portion of the support hole and discharges it from a discharge port by rotating a drive gear and a driven gear that mesh with each other in a circular support hole formed in a pump housing. A valve hole into which a valve member is slidably fitted into the pump housing is formed on a side of the support hole, and a relief passage that is opened and closed by sliding of the valve member is formed in communication with the valve hole. An oil pump characterized in that the relief passage extends in a tangential direction of the support hole and communicates with the suction port.