JPH1113641A - Oil pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil reserved in a suction port from leaking by forming a wall part between the suction port and a relief passage while communicating the suction port with the relief passage through a suction passage. SOLUTION: An oil pump is composed of a housing, an inner rotor 3 assembled in the housing, and an outer rotor 5 as a main constituting member. A suction port 19 is communicated with a relief passage 25 through a suction passage 23, and also a wall part 43 is formed between the suction port 19 and the relief passage 25. At the time of non-operation of oil pump, an oil sump S formed between an outer rotor 5 and the housing, and an engine block is not connected to the relief passage 25 directly, and thereby, it is possible to prevent oil in the oil sump S from flowing into a drain hole 41 through a valve passage 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pump for lubricating an engine used for a vehicle, a ship, or an aircraft.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 58-35212 or 58-33709 discloses a technique relating to a conventional oil pump. This includes a housing fixed to a block of the engine, an inner rotor rotatably installed in the housing, and transmitting rotation of an engine crankshaft via a pulley,
There is an oil pump provided with an outer rotor having internal teeth meshing with external teeth of an inner rotor.

In this oil pump, more play than is necessary for the function is provided between the engine block and the rotor in order to absorb a dimensional error between the pump chamber formed by the housing and the engine block and the rotor. ing.
This may cause oil leakage through the play at the time of starting the oil pump, which may cause a rise in hydraulic pressure.

[0004] In the case of an oil pump provided with an oil reservoir at the suction port, the accumulated oil fills the play between the engine block and the rotor, and the oil pressure can be increased.

[0005] However, in an oil pump having a drain passage for releasing the back pressure of the relief valve provided on the discharge side, the oil stored in the oil sump passes through a gap between the relief valve and the housing. Flows to the drain path and no oil remains in the oil sump.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an oil pump which solves the above-mentioned problems.

[0007]

According to a first aspect of the present invention, in order to solve the above-mentioned problems, a housing and an inner member rotatably installed in the housing and having a plurality of external teeth on an outer periphery are provided. A rotor, rotatably installed eccentrically with respect to the rotation axis of the inner rotor in the housing, comprising a plurality of inner teeth meshing with outer teeth of the inner rotor on an inner periphery, and the outer teeth and the inner teeth; An outer rotor forming a plurality of pump chambers therebetween, a suction port formed in the housing, communicating with the pump chamber and communicating with a suction path for sucking oil from outside, and formed in the housing; A discharge port communicating with the pump chamber, a valve path communicating with the discharge port, and a relief valve installed on the valve path communicating with the valve path; Together, through the suction path,
An oil pump includes a relief path communicating with the suction port, and a wall portion provided between the suction port and the relief path.

According to the oil pump of the first aspect, the suction port communicates with the relief path via the suction path, and the wall is formed between the suction port and the relief path. The oil stored in the suction port does not leak.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The features of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of an oil pump according to the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG.
3-3 is a sectional view of FIG. This oil pump has a housing 1 and an inner rotor 3 and an outer rotor 5 assembled in the housing 1 as main components.

As shown in FIG. 2, the housing 1 is mounted on the engine block 7 by mounting bolts (not shown). Between the housing 1 and the engine block 7, the right end of the rotor shaft 9 is press-fitted into its inner peripheral portion 3b, and rotation of an unillustrated engine crankshaft is transmitted via a pulley 11. An inner rotor 3 having an inner rotor 3 and inner teeth 5a meshing with outer teeth 3a provided on an outer peripheral portion of the inner rotor 3 is incorporated. A pump chamber P is formed between the outer teeth 3a of the inner rotor 3 and the inner teeth 5a of the outer rotor 5.

The left end of the rotor shaft 9 in FIG. 2 is rotatably supported by the housing 1 via a bearing 13, and the pulley 11 is fastened together by a pulley bolt 15. A pulley belt is stretched between the pulley 11 and a crankshaft (not shown), and the rotation of the crankshaft is transmitted.

An O-ring 17 is provided on the joint surface between the housing 1 and the engine block 7 so as to surround the outer rotor 5 to prevent oil from leaking to the outside. The engine block 7 has a suction port 19 communicating with the pump chamber P,
The discharge port 21 is provided so as to face the outer rotor 5 in the radial direction. The suction port 19 communicates with the suction path 23, and the suction path 23 has a relief path 2.
5 is connected. The lower side of the drawing of the suction path 23 faces an engine oil pan (not shown) via a strainer (not shown).

On the other hand, the discharge port 21 is connected to a discharge port of an oil pump (not shown) through a connection hole 27 to supply lubricating oil into the engine. The connection hole 27 connected to the discharge port 21 is connected to a valve path 29, and a relief valve 31 is provided on the valve path 29 in FIG.
Are disposed so as to be movable in the vertical direction. A plug 33 is screwed to the end of the valve path 29 so as to sandwich the gasket 35.

The plug 33 is provided with a concave portion 33a,
A compression spring 37 is provided between the recess 33 a of the plug 33 and the recess 31 a of the relief valve 31. I have. A relief hole 39 communicating with the relief path 25 is connected to the valve path 29,
As shown in FIG. 3, the biasing force of the compression spring 37 causes the relief valve 31 to move the relief valve 31 through the valve path 29.
When the relief valve 31 is in contact with the step portion 29a,
Thus, the communication between the valve path 29 and the relief hole 39 is cut off. The oil discharge pressure from the discharge port 21 is
After reaching the valve path 29 via the connection path 27, the discharge pressure is applied from above the relief valve 31 in FIG. When the discharge pressure of the oil pump exceeds a predetermined value, the relief valve 31 is moved downward in FIG. 3 against the urging force of the compression spring 37. The downward movement of the relief valve 31 causes the discharge port 21
A part of the oil discharged from the discharge port 39, the relief path 2
5, the oil pressure is returned to the suction path 23, so that the discharge pressure of the oil pump is maintained at a predetermined value or less.

Further, the relief valve 3 in the valve path 29
A drain hole 41 communicating with an oil pan (not shown) of the engine is connected downstream of the drain hole 41. Drain hole 41
Is used to release the back pressure of the relief valve 31 to the oil pan of the engine and return the oil on the discharge side leaking from the outer peripheral portion of the relief valve 31 to the oil pan.

As described above, the suction port 19 communicates with the relief path 25 via the suction path 23, and the wall 43 is formed between the suction port 19 and the relief path 25. When the oil pump is not operating,
Since the oil sump (S shown in FIGS. 1 and 2) formed between the outer rotor 5 and the housing 1 and the engine block 7 does not directly connect to the relief path 25, the oil sump in the oil sump Does not flow to the drain hole 41 via the valve path 29.

FIG. 4 is a front view of an oil pump according to a modified embodiment of the present invention. In this embodiment, FIG.
The O-ring 17a disposed on the joint surface between the housing 1 and the engine block 7 is
5, the oil in the oil reservoir does not leak to the relief path 25 via the joint surface between the housing 1 and the engine block 7.

[0018]

As described above, according to the oil pump of the present invention, an oil reservoir can be formed with a simple structure when the oil pump is not operating, so that the oil pump is compact and low-cost, and has a boosting performance at the time of starting. A good oil pump can be provided.

[Brief description of the drawings]

FIG. 1 is a front view of an oil pump according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is a front view of an oil pump according to a modification of the present invention.

[Explanation of symbols]

Reference Signs List 1 housing 3 inner rotor 3a external teeth 5 outer rotor 5a internal teeth 19 suction port 21 discharge port 23 suction path 25 relief path 29 valve path 31 relief valve 43
Wall P Pump room

Claims (1)

[Claims] 1. A housing, an inner rotor rotatably installed in the housing and having a plurality of external teeth on an outer circumference, and an eccentrically installed rotatably installed in the housing with respect to a rotation axis of the inner rotor. An outer rotor having a plurality of inner teeth on its inner periphery meshing with the outer teeth of the inner rotor, an outer rotor forming a plurality of pump chambers between the outer teeth and the inner teeth, and the pump formed on the housing; A suction port communicating with the chamber and communicating with a suction path for sucking oil from outside, a discharge port formed in the housing and communicating with the pump chamber, a valve path communicating with the discharge port, and the valve; A relief path communicating with the suction port through the suction path and communicating with the valve path via a relief valve installed on the path; An oil pump provided with a wall portion provided between the suction port and the relief path.