JP3956170B2 - Oil pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil pump, and more particularly to the structure of an inlet of an oil pump.
[0002]
[Prior art]
Conventionally, a trochoid rotor including an inner rotor and an outer rotor rotatably disposed inside the housing, a suction port for sucking oil into the rotor, and a discharge port for discharging oil by rotation of the rotor, Oil pumps that have a structure in which oil is filled only from the side of the outer rotor are known. In this way, the oil that fills the rotor surface from the side of the outer rotor is the outer rotor when the rotor rotates at high speed. And the oil filling into the rotor chamber formed by the inner rotor is not in time, a cavity is formed in the rotor chamber, and a cavitation problem occurs.
[0003]
Therefore, in order to prevent cavitation due to a decrease in oil filling property to the rotor chamber even when the rotor rotates at high speed, a radial communication hole is provided from the outer periphery of the outer rotor to the inner rotor side, and oil is also supplied from the outer periphery of the outer rotor. What is filled is disclosed in, for example, Japanese Utility Model Publication No. 2-43481. Further, Japanese Unexamined Utility Model Publication No. 6-18680 discloses that the communication hole becomes thinner as it goes to the inner rotor side.
[0004]
[Problems to be solved by the present invention]
However, when such an oil pump is applied to an engine of a vehicle, particularly when used at a high speed in a sports engine or the like, the oil that has entered the rotor is also subjected to centrifugal force only by providing a communication hole on the outer periphery of the outer rotor. Since the rotor surface is not sufficiently filled, it is not effective at high speed, and cavitation problems occur.
[0005]
Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an oil pump that can be sufficiently sucked from the suction port and does not generate cavitation even when used at high speed.
[0006]
[Means for Solving the Problems]
The technical means taken to solve the above problems, a housing, a trochoid rotor comprising an inner rotor and an outer rotor rotatably disposed within the housing, formed in the housing the rotor a suction port for sucking oil, and a discharge port for discharging oil from the rotor, the communicating hole for sucking oil into the inner chromatography rotor side from the outer periphery of said outer over rotor is provided radially on the outer rotor, In the oil pump, the communication hole is inclined with respect to the rotation direction of the rotor and becomes narrower toward the inner rotor side, and the inlet to the outer rotor is made thinner as the suction end is reached, and the outer rotor The angle of at least one of the suction start end and the suction end end is set to the same angle as the communication hole .
[0007]
With the above configuration, the suction port to the outer rotor is narrowed as it reaches the end of suction, so that the oil flow rate increases as it reaches the end of suction, and sufficient suction is possible to prevent cavitation.
[0008]
In this case, if the angle of the suction start end or the suction end end to the outer rotor is the same as that of the communication hole, the suction angle at the suction port is matched, and the suction becomes easier.
[0009]
If a flow direction changing means for changing the oil flow is provided at the suction port, the flow direction can be changed by the flow direction changing means, and the flow rate of oil at the suction port can be increased during suction.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0011]
The housing 1 has an inner tooth 5a that is directly connected to the crankshaft side of the engine or indirectly driven by a belt via a pulley, and an inner tooth 5a that is one tooth larger than the number of outer teeth 3a of the inner rotor 3. An outer rotor 5 that rotates following the rotation of the inner rotor 3 is rotatably disposed in a state in which the circumferential direction is supported by two axial surfaces of the housing and two support portions 1a. The inner rotor 3 and the outer rotor 5 constitute a trochoid oil pump 10.
[0012]
The housing 1 is configured such that engine oil (hereinafter referred to as oil) accumulated in the oil pan 14 can be pumped through a net-like oil strainer 13 provided at the suction port on the oil suction side. Oil is sucked from the outer rotor 5, and the rotor surface 4 formed between the outer rotor 5 and the inner rotor 3 is filled with oil by rotating the trochoid rotor, and the oil is discharged from the discharge port 21 to be discharged. The oil is supplied to various parts of the engine through the flow path 22. Further, a flow path 25 communicating with the relief valve 31 is formed in the middle of the flow path 22, and the valve is opened when the pressure of the discharge port 21 reaches a predetermined pressure (for example, 6 kgf / cm ² ). A relief valve 31 for returning the pressure of the discharge port 21 to the suction port 19 is provided. The relief valve 31 can suppress the pressure of the discharge port 21 to a predetermined pressure.
[0013]
Next, the trochoid rotor will be described. The outer rotor 5 that meshes with the outer teeth 3a of the inner rotor 3 by the inner teeth 5a is provided with a communication hole 2 from the outer periphery to the rotor surface 4 so that not only the rotor side surface but also the thick portion of the outer rotor 5 is provided. Oil can be filled into the rotor surface 4 also from the communication holes 2 formed at five locations. In particular, in this case, since it is expensive to provide the communication hole 2 by machining or the like, the rotor 3 is divided into two in the axial direction, and the two communication holes 2 having shapes corresponding to each other are formed and overlapped. Thus, a method of forming the radial communication holes 2 is adopted. In order to improve the oil filling property even at a high speed of the rotor, the communication hole 2 is made thinner from the outer periphery toward the inner peripheral surface on which the inner rotor 3 is disposed, so that the oil filling the rotor surface 4 is reduced. The flow rate is increased. With such a configuration, the communication hole 2 can be provided in the outer rotor 5 without machining with a sintered metal or the like. The communication hole 2 is formed in an oblique direction with a predetermined angle so that oil can be filled against centrifugal force even when the rotors 3 and 5 rotate at high speed.
[0014]
Furthermore, since the sufficient oil filling property cannot be obtained at high speed rotation with only the communication hole 2, the suction end 19 is gradually narrower at the suction port 19 of the housing 1 than the suction start end 1 b to the outer rotor 5. By doing so, the oil can easily enter the communication hole 2 due to the viscosity of the oil with respect to the rotor rotation direction. In this manner, the suction end 1c of the suction port 19 has a throttle shape, thereby increasing the flow rate of oil and improving the suction efficiency.
[0015]
In this case, by increasing the suction efficiency by making the suction angle of the suction start end 1b or suction end 1c formed in the housing 1 coincide with the angle of the communication hole 2 provided in the outer rotor 5. Yes.
[0016]
Further, if the partition wall (flow direction changing means) 12 for changing the oil flow is provided in the housing 1 as a single body or separately in the suction port 19 in order to improve the oil filling property, the flow when the oil flows. Resistance can be reduced, oil filling performance from the communication hole 2 can be improved, and cavitation can be suppressed.
[0017]
【effect】
According to the present invention, a housing, a trochoidal rotor including an inner rotor and an outer rotor that are rotatably disposed inside the housing, a suction port that is formed in the housing and sucks oil into the rotor, A discharge port for discharging oil from the rotor is provided, and communication holes for sucking oil from the outer periphery of the outer rotor to the inner rotor side are provided radially in the outer rotor, and the communication holes are inclined with respect to the rotation direction of the rotor, In the oil pump that becomes thinner as it goes to the inner rotor side, the suction port to the outer rotor is made thinner as the suction end is reached, so that the suction port to the outer rotor is made thinner as the suction end is reached. As the end of inhalation is reached, the oil flow rate increases and sufficient suction is possible. Shon can be prevented.
[0018]
In this case, if the angle of the suction start end or the suction end end to the outer rotor is the same as that of the communication hole, the suction angle at the suction port is matched, and the suction becomes easier.
[0019]
If the flow direction changing means for changing the oil flow is provided at the suction port, the flow direction can be changed by the flow direction changing means, and the flow rate of oil at the suction port can be increased during suction.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an oil pump according to an embodiment of the present invention.
[Explanation of symbols]
1 Housing 1b Suction start end 1c Suction end end 2 Communication hole 3 Inner rotor (rotor)
4 Rotor surface 5 Outer rotor (rotor)
12 Partition wall (flow direction changing means)
19 Suction port 21 Discharge port 22, 25 Flow path 31 Relief valve

Claims (2)

A trochoidal rotor including a housing, an inner rotor and an outer rotor that are rotatably disposed inside the housing, a suction port that is formed in the housing and sucks oil into the rotor, and discharges oil from the rotor and a discharge port for the communication hole from the outer periphery of the outer rotor sucks the oil to the inner rotor side are provided radially on the outer rotor, the communication hole is inclined with respect to the rotational direction of the rotor, the inner In the oil pump that becomes thinner as it goes to the rotor side, the suction port to the outer rotor is made thinner as the suction end is reached, and at least one angle of the suction start end and the suction end end to the outer rotor is the communication An oil pump characterized by the same angle as the hole . The oil pump according to claim 1 , wherein flow direction changing means for changing the flow of oil is provided at the suction port.

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