JPH0746780Y2 - Internal combustion engine oil pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an oil pump for an internal combustion engine.

<Prior Art> Conventionally, as shown in FIG. 7 and subsequent figures, the external gear 2 is eccentrically arranged with respect to the external gear 2 fixed to the front end side of a crankshaft 1 of an internal combustion engine. A part of the internal gear 3 having a larger number of teeth than 2 is meshed, the external gear 2 and the internal gear 3 are housed in the pump housing 4, the open end thereof is covered with the cover 5, and the crankcase 6 is mounted. An oil pump 7 for an internal combustion engine that is configured as above is known. Reference numeral 8 is a seal, and 9 is a small screw for fixing the cover 5 to the pump housing 4.

In the oil pump 7 for an internal combustion engine as described above, the external gear 2 and the internal gear 3 meshing with the external gear 2 are rotated by the rotation of the crankshaft 1 in the direction of the arrow by the internal combustion engine, and the oil is sucked into the suction port 4a of the pump housing 4. It is sucked in from, discharged from the outlet 4b after being compressed between the external gear 2 and the internal gear 3. At this time, the external gear 2 and the internal gear 3 maintain a minute gap between the pump housing 4 and the inner surfaces of the cover 5 and rotate while forming an oil film in this gap, thereby sealing. Although it should be maintained, in reality, as shown in FIG. 9, a small amount is present especially between the external gear 2 and the inner surface of the cover 5, between the cover 5 and the outer circumference of the crankshaft 1, and the like. There is a gap s, and air may infiltrate from the outside through the gap s or oil inside may leak. Most of the latter oil leaks into the oil pan, but the former air mixes into the oil as air bubbles, which are crushed in the lubricated parts of the parts and make direct contact between metal parts, resulting in increased seizure and noise. Sometimes caused a problem that leads to.

The above-mentioned problems are further increased by the increase in the hydraulic pressure supplied with the increase in speed of the internal combustion engine, resulting in the deformation of the pump housing 4 and the cover 5, the increase of the gap s, and the increase of the amount of infiltrated air.

For this reason, the thicknesses of the pump housing 4 and the cover 5 have been increased, but this increases the weight and volume of the oil pump itself, which has a problem of having a great influence on the internal combustion engine.

Therefore, as in the invention disclosed in Japanese Patent Laid-Open No. 61-104178, in a rotary oil pump device, the end surface of the rotary member or the supporting surface of the fixed member facing the end surface with a gap therebetween is One of them is provided with a plurality of oil guide grooves so as to draw the oil toward the center of the rotary member. Since oil is always drawn between the end surface of the rotary member and the support surface of the fixed member such as the housing and the thrust washer, a large amount of oil may leak from this portion.

Further, as disclosed in, for example, Japanese Utility Model Laid-Open No. 59-175618, an annular groove is provided in either or both of the sliding contact portion between the external gear and the cover in the oil pump for an internal combustion engine. The high pressure oil that has passed through the clearance of the sliding contact portion is one side of the annular groove (half of the annular groove).
Flow into the other side of the annular groove (the other half of the annular groove), then flow or leak while satisfying the clearance on the suction side and the clearance between the cover and the crankshaft, or the above-mentioned clearance is always maintained. It keeps the oil film formed and shuts off the air trying to enter.

However, the oil pressure generated by the flow of oil flowing through the suction side clearance has a function of blocking the invasion of air, but at the same time, this annular groove extends from the high pressure side (discharge port side) to the low pressure side (suction port side). Since it makes the oil flow smooth, it rather plays a role in greatly increasing oil leakage.

Therefore, as disclosed in Japanese Utility Model Laid-Open No. 61-10985, a groove in the circumferential direction is formed on one of the sliding contact surfaces of the gear of the oil pump and the casing, and a sealing made of resin or a sintered material is formed in the groove. And a spring that presses this sealing against the other sliding contact surface is also devised.

<Problems to be solved by the invention> However, since the direction of the hydraulic pressure applied to the sealing is different between the high pressure side and the low pressure side (the high pressure side is the centripetal direction, and the low pressure side is the centrifugal direction), the sealing action is not effective. Not only
The oil flow is blocked by the sealing, and seizure may occur on the sliding contact surface outside the sealing.

The present invention was devised as a solution to the above-mentioned problems by focusing on the difference in the direction of hydraulic pressure with respect to the sealing, and provided with an annular groove that can control the amount of oil that enters and overflows the annular groove. The purpose is to provide an oil pump.

<Means for Solving the Problems> In order to achieve the above object, an oil pump of an internal combustion engine of the present invention has an external gear 3 fixed to the front end side of a crankshaft 1 of the internal combustion engine and having a larger number of teeth than the external gear. In an oil pump for an internal combustion engine in which a part of the internal gear 2 is housed in a pump housing 10 in a meshed state, the open end thereof is covered with a cover 11 and attached to a crankcase, when the external gear 3 rotates. On one or both surfaces of the pump housing 10 or the cover 11 facing each other with a minute gap, the annular groove 12 and the groove connected to the annular groove 12 extend in the centrifugal direction from the annular groove 12 on the high pressure side of the oil, On the low-pressure side, a large number of oil flow control supporting grooves 13, 14 extending centrically from the annular groove 12 are formed.

<Operation> With the above configuration, when the internal combustion engine is operated and the crankshaft 1 rotates the external gear 3, the oil is sucked from the intake port 10a by the action of the gear and the internal gear 2 meshing with the external gear 3.
The oil that is compressed between the two gears and is discharged from the discharge port 10b and is entrained between the side surface of the rotating external gear 3 and the cover 11 at this time fills the annular groove 12 and the oil flow control supporting grooves 13 and 14. , Then, on the discharge side, that is, on the high pressure side, the oil tries to overflow from the oil flow control groove 13 in the centrifugal direction,
The oil flow attempting to enter the annular groove 12 and the oil flow control support groove 13 from the high pressure side is pushed back to prevent the inflow of excessive oil and control the oil amount.

Further, on the suction side, that is, on the low pressure side, the oil flow attempting to leak to the low pressure side is restricted by overflowing from the oil flow control support groove 14 in the centripetal direction.

<Embodiment> An embodiment will be described in detail with reference to FIGS. 1 to 4 in which the same reference numerals and numbers as those in FIG. 7 and subsequent figures represent the same parts and members. A member that faces the gear 2 with a minute gap when rotating,
For example, on the surfaces of the pump housing 10, the cover 11 and the like (the surface 10c of the pump housing 10 and the surface 11a of the cover 11 in the figure), an annular groove 12 serving as a connecting groove and a high pressure side (the discharge port 10 On the side closer to −b), a number of oil flow control support grooves 13 extending in the centrifugal direction from the annular groove 12 are provided, and on the low pressure side (the side closer to the suction port 10-a), a plurality of oil flow control supporting grooves 13 extending in the centripetal direction from the annular groove 12 are provided. The oil flow control supporting groove 14 is formed. In the illustrated example, as shown in FIG. 2, a single annular groove 15, 16 is provided at a position facing the oil flow control supporting grooves 13, 14 on both side surfaces of the external gear 2.
Is formed.

The oil flow control support grooves 13, 14 have a spiral shape with a fine tip as shown in FIG. 4 (a), a strip shape as shown in FIG. 4 (b), and as shown in FIG. 4 (c). It is conceivable that the connecting groove is formed in the shape of a sword and the like, and both are formed along the rotational direction of the external gear 2 as shown in FIGS. Between the annular groove 12 and the discharge port 4d, slightly obliquely, and between the annular groove 12 formed near the suction port 4c on the low pressure side and near the outer peripheral surface of the crankshaft 1 It is formed so as to be rolled up.

In the oil pump of the present invention configured as described above, when the internal combustion engine is operated and the crankshaft 1 rotates the external gear 2, the oil pump is operated by the action of the gear 2 and the internal gear 3 meshing therewith. Inhaled from the suction port 4a of the housing 4,
The annular groove 12, which is a connecting groove, is the oil that is compressed between the two gears 2 and 3 and is discharged from the discharge port 4b, and is rotated between the side surface of the external gear 2 that rotates at this time and the pump housing 4 and the cover 5. Single annular groove 15, 16 and oil flow control groove 13,
However, on the discharge side, that is, on the high-pressure side, oil tends to overflow from the oil flow control support groove 13 in the centrifugal direction, so that the high pressure side causes the annular grooves 12, 15 and the oil flow control support groove 13 to flow. The oil flow that is about to enter is pushed back to prevent excessive oil inflow and control the oil amount.

Further, on the suction side, that is, on the low pressure side, the oil flow attempting to leak to the low pressure side is restricted by overflowing from the oil flow control support groove 14 in the centripetal direction.

<Effect of the Invention> In the present invention, the external gear 3 is engaged with a part of the internal gear 2 having a larger number of teeth than that of the internal gear 2 and accommodated in the pump housing 10, and the opening end thereof is covered with a cover 11. In the pump,
On one or both surfaces of the pump housing 10 or the cover 11 facing each other with a minute gap when the external gear 3 rotates, the annular groove 12 and the annular groove 12 are connected to the groove and the annular groove 12 is provided on the high pressure side of oil. Since a large number of oil flow control support grooves 13 and 14 extending in the centrifugal direction and extending in the centripetal direction from the annular groove 12 on the low pressure side of the oil are formed, the oil flows in the centrifugal direction from the oil flow control support groove on the high pressure side. The oil flow that attempts to overflow into the annular groove and the oil flow control support groove from the high pressure side is pushed back to prevent excessive oil inflow and control the oil amount, and at the same time, to the suction side, that is, the low pressure side. On the side, it is possible to limit the oil flow that tries to leak to the low pressure side by overflowing from the oil flow control support groove in the centripetal direction, and between the external gear and the inner surface of the cover, and between the cover and the outer circumference of the crankshaft. Minimize oil leakage from minute gaps such as Moreover to ensure the oil film of the gap is effective can prevent the ingress of air.

[Brief description of drawings]

1 is a partially cutaway front view of the oil pump of the present invention, FIG.
The figure is the same sectional view, FIG. 3 is a front view of the annular groove and the oil flow control support groove, FIG. 4 is a view of the oil flow control support groove, and FIG. 5 is the oil flow control support groove on the low pressure side of the oil pump. FIG. 6, FIG. 6 is an operation diagram of the oil flow control groove on the high pressure side, FIG. 7 is a partially cutaway front view of a conventional oil pump, FIG. 8 is the same sectional view, and FIG. FIG. 8 is a partially enlarged view of FIG. 8. 1; crankshaft, 2; external gear, 3; internal gear, 4, 10; pump housing, 5, 11; cover, 6; crankcase, 7;
Oil pump, 8; seal, 12; annular groove (as connecting groove), 13, 14; oil flow control supporting groove, 15, 16; annular groove (single unit).

Claims (1)

[Scope of utility model registration request] 1. An internal gear 2 having a larger number of teeth than an external gear 3 fixed to the front end side of a crankshaft 1 of an internal combustion engine is housed in a pump housing 10 in a state of being engaged with the external gear 3. In an oil pump for an internal combustion engine in which an open end is covered with a cover 11 and attached to a crankcase, a pump housing 10 in which the external gear 3 confronts with a minute gap during rotation.
Alternatively, on one or both surfaces of the cover 11, the annular groove 12 and the groove connected to the annular groove 12 extend in the centrifugal direction from the annular groove 12 on the high pressure side of the oil, and extend in the centripetal direction from the annular groove 12 on the low pressure side of the oil. An oil pump for an internal combustion engine, characterized in that a large number of oil flow control grooves 13, 14 are formed.