JPH1047259A - Oil pump of internal combution engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vibration of an oil pump case wall surface, and restrain generation of vibration and a noise of an oil pump by setting a thickness of a sealed side wall and a delivery side wall of a pump chamber of an oil pump case thicker than a thickness of a suction side wall and the other wall. SOLUTION: An oil pump case 4 of a trochoidal oil pump 2 is composed of a front case 12 and a rear case 16 joined to this by a joining bolt 14. This front case 12 is composed of a front suction side wall 40, a front sealed side wall 42 of a pump chamber, a front delivery side wall 44 and the other front wall, but in this case, a thickness of the front sealed side wall 42 and the front delivery side wall 44 is formed larger by a prescribed quantity than a thickness of the front suction side wall 40 and the other front wall. Therefore, even if cavitation and a liquid hammer are generated, vibration of a wall surface of the oil pump case 4 is reduced, and vibration and a noise of the oil pump 2 are reduced.

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 an internal combustion engine, and more particularly to an oil pump for an internal combustion engine capable of reducing vibration and noise caused by cavitation and liquid hammer.

[0002]

2. Description of the Related Art In an internal combustion engine, an oil pump is provided to supply lubricating oil to each moving part. As this oil pump, for example, there is a trochoid oil pump.

That is, as shown in FIG. 20, in a trochoid type oil pump 202, an oil pump shaft 204
Inner rotor 206 fixed to the inner rotor 20 and the inner rotor 20
The outer rotor 208 meshed with the outer rotor 208 is accommodated in the oil pump case 210, and the outer rotor 308 is also rotated by the rotation of the inner rotor 206 accompanying the rotation of the oil pump shaft 204, so that the inner rotor 206 and the outer rotor 208 are rotated.
A pump action is performed by a change in volume of the pump chamber 212, which is a space formed by the above, and oil is sucked from the suction port 214 and discharged to the discharge port 216.
The pump chamber 212 is formed within a predetermined closed space S as shown in FIG.

[0004] Further, such an oil pump includes:
For example, Japanese Utility Model Publication No. 60-24882, Japanese Utility Model Application Publication No. 1-1
No. 48081. 60-24
No. 882 discloses a method in which a partition wall hanging in the vicinity of a bearing cap is formed in a crankcase with a gap in front and rear, and a stiffener having at least four feet is bolted to a lower surface of the partition wall. By attaching the oil pump to the stiffener, the oil pump is connected to the inside of the crankcase via an oil discharge conduit formed in the stiffener, thereby increasing the rigidity of the crankcase, reducing engine noise, and installing the oil pump. It can improve the accuracy and reduce the number of assembly steps. Japanese Unexamined Utility Model Publication No. 1-148081 discloses a communication passage that connects a discharge port with a portion after the space volume starts to decrease in a seal land portion from a suction port to a discharge port, and a space inside the space. When the fluid pressure exceeds a predetermined discharge pressure, a pressure relief valve mechanism for opening the communication passage is provided.

[0005]

However, in the trochoid type oil pump, the volume of the pump chamber is increased on the suction side, while the pressure is rapidly reduced and increased on the discharge side. In some cases, the gas contained in the oil is bubbled to cause cavitation. Also, when the pump chamber communicates with the discharge port, high-pressure oil at the discharge port flows back into the pump chamber, so that a liquid hammer may occur. Vibrations due to such cavitation and liquid hammer propagate in the pump chamber communicating with the discharge port and in the oil in the discharge port, causing the wall surface of the oil pump case to vibrate, generating severe vibration and noise. There was an inconvenience.

[0006]

SUMMARY OF THE INVENTION Accordingly, in order to eliminate the above-mentioned disadvantages, the present invention rotates an inner rotor and an outer rotor incorporated in the inner rotor in an oil pump case to thereby form inner teeth of the inner rotor and the outer rotor. In the oil pump of an internal combustion engine that introduces oil from a suction port and discharges the oil to a discharge port by a change in volume of a pump chamber formed between the outer teeth of the pump chamber and the pump chamber, the pump chamber of the oil pump case is sealed. The thickness of the side wall and the discharge side wall is set to be larger than the thickness of the suction side wall and other walls.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, in an oil pump, even if cavitation or liquid hammer occurs, the thickness of a closed side wall or a discharge side wall is formed larger than the thickness of a suction side wall or another wall. Therefore, the vibration of the wall surface of the oil pump case can be reduced, and the vibration and noise of the oil pump can be reduced. Further, only the thickness of the closed side wall and the discharge side wall is increased, so that the oil pump case Can be made lighter and more compact than when the overall thickness is increased.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 to 16 show a first embodiment of the present invention.
It shows an embodiment. 1 to 5, reference numeral 2 denotes a trochoid type oil pump installed in an internal combustion engine (not shown). The oil pump 2 according to the first embodiment includes:
It is a separate type from a cylinder block (not shown).

The oil pump 2 has an inner rotor 8 which is spline-fitted to an oil pump shaft 6 which is a rotary shaft in an oil pump case 4, and an outer rotor 10 incorporated in the inner rotor 8. The oil pump case 4 includes a front case 12 and a rear case 16 connected to the front case 12 by connecting bolts 14.

As shown in FIG. 2, the inner rotor 8 has a plurality of inner teeth 8a. Outer rotor 10
Are formed with a plurality of outer teeth 10a which is one more than the number of the inner teeth 8a.

An inner rotor 8 is provided between the inner teeth 8a of the inner rotor 8 and the outer teeth 10a of the outer rotor 10.
In addition, a pump chamber 18 is formed as a space which moves while expanding and contracting in the rotation direction when the outer rotor 10 rotates, and which changes its volume. The pump chamber 18 is formed within a predetermined closed space S as shown in FIG.

As shown in FIG. 2, the oil pump 2 is provided with a suction port 20 for sucking oil and a discharge port 22 for discharging oil.

As shown in FIGS. 3 to 5, a sprocket 24 is mounted on the oil pump shaft 6 with sprocket mounting bolts 26. A drive chain 28 is wound around the sprocket 24.

The oil pump 2 is provided with a relief valve 30 and an oil strainer 36 with strainer mounting bolts 34 via O-rings 32,32.

As shown in FIGS. 6 to 10, the front case 12 has a rotor housing chamber 38 for housing the inner rotor 8 and the outer rotor 10. The front case 12 includes a front suction side wall 40, a front sealed side wall (hatched right portion) 42 of the pump chamber 18, a front discharge side wall (left hatched portion) 44, and other front walls. At this time, the thickness of the front closed side wall 42 and the front discharge side wall 44 (shaded portions on the right and left sides) is formed to be larger than the thickness of the front suction side wall 40 and other front walls by a predetermined amount.

As shown in FIGS. 11 to 16, the rear case 16 is composed of a rear discharge side wall (shaded left portion) 46, a rear closed side wall (not shown), and other walls. The thickness of the rear discharge side wall 46 and the thickness of the closed side wall are formed to be predeterminedly larger than the thicknesses of the other walls.

A discharge pipe (not shown) is attached to the rear case.

Next, the operation of the first embodiment will be described.

When the oil pump shaft 6 rotates, the inner rotor 8 and the outer rotor 10 rotate, and the inner rotor 8 rotates.
The oil introduced from the suction port 20 is discharged to the discharge port 22 by a change in volume of the pump chamber 18 formed between the inner teeth 8a of the outer rotor 10 and the outer teeth 10a of the outer rotor 10 and in the closed space S.

At this time, the volume of the pump chamber 18 increases on the suction side and decreases on the discharge side.
In the sealed space S from 0 to the discharge port 22, rapid decompression and pressurization are performed in the pump chamber 18, and the gas contained in the oil is bubbled to generate cavitation. When the pump chamber 18 communicates with the discharge port 22, the high-pressure oil in the discharge port 22 is discharged from the pump chamber 1.
8, the fluid hammer is generated.

However, in the first embodiment, since the thickness of the sealing side wall and the suction side wall in the oil pump case 4 is formed larger than the thickness of the discharge side wall and other walls, cavitation and liquid Even if a hammer occurs, the vibration of the wall surface of the oil pump case 4 can be reduced, and the vibration and noise of the oil pump 2 can be reduced.

Further, in the oil pump case 4, only the sealing side wall and the discharge side wall are only set to be thick, so that the oil pump case 4 can be made lighter and more compact as compared with the case where the wall thickness of the oil pump case 4 is entirely increased. it can.

FIGS. 17 to 19 show a second embodiment of the present invention.

In the second embodiment, the same reference numerals are given to portions having the same functions as those in the first embodiment described above.

The feature of the second embodiment is that the oil pump 2 is of a built-in type in a cylinder block, and a chain case and an oil pump case are used as a front case. This eliminates the need for a rear case.

That is, as shown in FIG. 17, a chain case 102 functions as a front case of the oil pump case 4 attached to the internal combustion engine.

In the chain case 102, the rotor accommodating chamber 1 accommodating the inner rotor 8 and the outer rotor 10 is provided.
04 is formed. The inner rotor 8 is rotated with rotation of a crankshaft (not shown).

The wall thickness of the closed side and the discharge side wall (portion shaded left) 106 around the rotor housing chamber 104 is set to be thicker than the other walls.

According to the structure of the second embodiment, the same effects as those of the first embodiment can be obtained even if the oil pump is of a built-in type.
02 and a cylinder block can be used instead of the rear case, so that the configuration can be simplified.

[0030]

As is apparent from the above detailed description, according to the present invention, the thickness of the closed side wall and the discharge side wall of the pump chamber of the oil pump case is set to be larger than the thickness of the suction side wall and other walls. Thus, even if cavitation or liquid hammer occurs, the vibration of the wall surface of the oil pump case can be reduced, and the vibration and noise of the oil pump can be reduced.

Further, since only the thickness of the sealed side wall and the discharge side wall is increased, the weight and the size of the oil pump case can be reduced as compared with the case where the overall thickness is increased.

[Brief description of the drawings]

FIG. 1 is a front view of an oil pump without a sprocket.

FIG. 2 is a front view of the oil pump without a front case.

FIG. 3 is a half sectional view of an oil pump.

FIG. 4 is a cross-sectional view taken along line 〓-〓 of FIG. 3;

FIG. 5 is an assembly view of the oil pump.

FIG. 6 is a front view of a front case.

FIG. 7 is a cross-sectional view taken along line 〓-〓 of FIG. 6;

FIG. 8 is a bottom view of the oil pump of FIG.

FIG. 9 is a left side view of the oil pump of FIG.

FIG. 10 is a diagram illustrating a portion where the thickness is increased.

FIG. 11 is a front view of a rear case.

FIG. 12 is a bottom view of the rear case of FIG. 11;

FIG. 13 is a partial cross-sectional view taken along line 〓〓-〓〓 of FIG. 11;

FIG. 14 is a rear view of the rear case of FIG. 11;

FIG. 15 is a left side view of the rear case of FIG. 11;

16 is a side view of the rear case indicated by an arrow 〓〓 in FIG.

FIG. 17 is a rear view of the chain case of the second embodiment.

FIG. 18 is a cross-sectional view taken along line 〓〓-〓〓 of FIG. 17;

FIG. 19 is an enlarged view of the rotor housing chamber of FIG. 17;

FIG. 20 is a configuration diagram of a conventional oil pump.

[Explanation of symbols]

 Reference Signs List 2 oil pump 4 oil pump case 6 oil pump shaft 8 inner rotor 10 outer rotor 12 front case 16 rear case 18 pump chamber 20 suction port 22 discharge port 40 front suction side wall 42 front sealing side wall 44 front discharge side wall

Claims (3)

[Claims] An inner rotor and an outer rotor incorporated in the inner rotor are rotated in an oil pump case, and a change in volume of a pump chamber formed between inner teeth of the inner rotor and outer teeth of the outer rotor causes a change in volume of a pump chamber from the suction port. In the oil pump of the internal combustion engine that introduces the oil and discharges the oil to the discharge port, the thickness of the closed side wall and the discharge side wall of the pump chamber of the oil pump case is larger than the thickness of the suction side wall and other walls. An oil pump for an internal combustion engine characterized by being set thick. 2. The closed side wall and the discharge side wall of the pump chamber in both a front case in which the inner rotor and the outer rotor are incorporated and a rear case to which a discharge pipe is attached, when the oil pump is a separate type from a cylinder block. 2. The oil pump for an internal combustion engine according to claim 1, wherein the thickness of the oil pump is set larger than the thickness of the suction side wall and other walls. 3. When the oil pump is built in a cylinder block, the thickness of the closed side wall and the discharge side wall of the pump chamber is set to be thicker than the thickness of the suction side wall and other walls only in the front case. 2. The oil pump for an internal combustion engine according to claim 1, wherein: