JPH10213079A - Trochoid pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce oil pressure to act on a rotary shaft as thrust force, and make a rotary characteristic of a trochoid pump in a good condition by arranging oil pressure reducing means of leak oil acted on the rotary shaft in the thrust direction, on a cap part for composing the casing of the pump. SOLUTION: An outer rotor 2A is rotated around a rotary shaft 8, the condition of a space formed between the inner circumferential part of the outer rotor 2A and an inner rotor 2B is changed from a condition communicated with a suction side port to a condition communicated with a delivery side port through a condition which is tightly closed, and a pump action is exhibited. In a trochoid pump P which is formed into such constitution, an oil pressure reducing means 11 is arranged to reduce pressure of oil which is leaked to a part which is a sliding contact part between a rotor 2 and a cap part 1B in association with pump action. Namely, a small hole 12 is drilled on a cap part 1B opposed to a rotary shaft end surface 8A exposed to the inside of the cap 1B. In this case, the hole diameter of the small hole 12 is may be set to nearly ϕ0.6 to ϕ1.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine such as a motorcycle, a car, a personal watercraft, and the like.
The present invention relates to a trochoid pump optimal for an oil pump for lubricating oil of a cycle engine.

[0002]

2. Description of the Related Art Internal combustion engines, for example, four-stroke engines such as motorcycles, automobiles, and personal watercrafts, generally include:
An oil pump is provided for supplying oil from an oil pan provided at a lower portion of the engine to a lubricating portion above the oil pan. This oil pump sucks oil accumulated in an oil pan from an inlet through an oil filter, pressurizes the oil, and supplies it to a lubrication system flow path from an outlet.
Examples of this type of prior art include, for example, Japanese Utility Model Laid-Open No. 2-807.
There is No. 20.

There is a trochoid pump as an oil pump applied to a four-stroke engine such as a motorcycle.

FIG. 5 is a side view showing a part of the internal structure of the conventional trochoid pump in cross section, and FIG. 6 is a front view showing a part of the internal structure of the trochoid pump in the same manner.

In FIGS. 5 and 6, the trochoid pump P
Includes a rotor 2 in a casing 1. The casing 1 is composed of a casing body 1A and a cap 1B. The casing 1A has a rotor housing 3 recessed therein, and the cap 1B is axially symmetrical with the cap 1B corresponding to the rotor housing 3. The suction-side port 4 and the discharge-side port 5 are recessed at the positions, and these ports 4 and 5 communicate with the suction passage 6 and the discharge passage 7 provided in the casing body 1A, respectively.

The rotor 2 comprises an outer rotor 2A and an inner rotor 2B. The outer rotor 2A having a cylindrical outer periphery and an inner peripheral portion formed into an internal gear (star shape) is rotatably mounted on the rotor housing 3. The inner rotor 2B is rotatably accommodated therein, and the inner rotor 2B is fixed to the rotating shaft 8 by using a driving pin 9, and the rotating shaft 8 is fixed to the rotor housing 3 and the outer rotor 2.
It is rotatably supported by a support hole 10 provided in the casing main body 1A eccentrically from the center of A.

In the above configuration, when the rotating shaft 8 rotates, the inner rotor 2B rotates while sliding on the inner peripheral portion of the outer rotor 2A, and the outer rotor 2A rotates.
And the space formed between the inner peripheral portion of the outer rotor 2A and the inner rotor 2B communicates with the suction-side port 4 through the hermetically sealed state to communicate with the discharge-side port 5 And exerts a pump action.

That is, when the space formed between the outer rotor 2A and the inner rotor 2B communicates with the suction-side port 4, the volume of the space gradually increases, and the oil accumulated in the oil pan is sucked in through the suction passage 6. Next, in the sealed state, the volume of the space is gradually reduced to pressurize the oil in the space, and the space communicates with the discharge port 5 to discharge and supply the pressurized high-pressure oil to the lubrication-required portion of the engine. .

[0009]

As described above, in a trochoid pump having a structure in which a rotating shaft is supported by a support hole provided in a casing main body and an inner rotor is cantilevered, a rotating shaft, an inner rotor and The fixing relationship is that the dimensional accuracy allows some movement in the thrust direction, but the end face of the rotating shaft on the rotor fixed side penetrates the inner rotor and is exposed facing the inside of the cap part, so that the pump action A plurality of pressure fluctuations occur per rotation based on the rotation of the rotor, and the oil pressurized in synchronization with the pressure fluctuations leaks into the sliding contact surface between the rotor and the cap portion, and the oil of the leaked oil The pressure acts as a thrust force on the rotor.

As a result, if the oil pressure of the leak oil acts on the end face of the rotating shaft exposed inside the cap portion to slightly vibrate the rotating shaft in the thrust direction, the rotational characteristics of the trochoid pump are affected. There is.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned technical problems, and a trochoid pump according to the present invention is provided with a cap portion constituting a casing of a pump in a thrust direction with respect to a rotating shaft. Prevents the oil pressure of the oil leaking to the sliding contact surface between the rotor and the cap from acting as a thrust force on the rotating shaft by adopting the structure with the means for reducing the oil pressure of the leak oil acting on the rotating shaft. However, the rotation characteristics of the trochoid pump are not affected.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a trochoid pump in which a rotary shaft is supported by a support hole provided in a casing body constituting a casing and an inner rotor is cantilevered. In the cap part,
Oil pressure reducing means is provided for reducing the oil pressure of oil leaking to the sliding contact surface between the rotor and the cap portion acting on the rotating shaft in the thrust direction.

As the above oil pressure reducing means, any means can be used as long as it reduces the oil pressure of the leak oil acting on the end face of the rotating shaft exposed inside the cap portion in the thrust direction. As the oil pressure reducing means, a small hole is formed in the cap portion corresponding to the rotating shaft, and the pressure of the leak oil can be reduced by discharging the leak oil from the small hole. In addition, as for the size of this small hole, in the case of a trochoid pump applied to a four-stroke engine of a motorcycle, it is preferable that the hole diameter be approximately φ0.6 to φ1.0.

Further, as another oil pressure reducing means, a guide recess is provided on the surface of the cap portion, and a part of the high-pressure oil pressurized from the guide recess is guided to the discharge side. The pressure can be reduced.

Further, as another oil pressure reducing means, if a pressure relief groove communicating from the end of the rotary shaft to the low pressure side is provided on the cap portion surface, leak oil from the end of the rotary shaft is released to the low pressure side to be provided on the end surface of the rotary shaft. The applied surface pressure can be reduced.

[0016]

Embodiments will be described with reference to the drawings.
The basic configuration of the trochoid pump is common to the trochoid pump of FIGS. 5 and 6 described above. Therefore, in the following description, the same parts as those in FIGS. 5 and 6 are denoted by the same reference numerals.

That is, in FIGS. 1 to 4, the trochoid pump P includes a rotor 2 in a casing 1,
The casing 1 is composed of a casing body 1A and a cap 1B, and a rotor 2 composed of an outer rotor 2A and an inner rotor 2B is rotatably fitted in a rotor housing 3 recessed in the casing body 1A,
The inner rotor 2B is fixed to the rotating shaft 8 using a driving pin 9, and the rotating shaft 8 is eccentric from the center of the rotor housing portion 3 and the center of the outer rotor 2A.
A is rotatably supported by a support hole 10 provided in A, and a suction port 4 and a discharge port 5 are recessed in the cap portion 1B corresponding to the rotor housing portion 3 at axially symmetric positions.
These ports 4 and 5 communicate with a suction passage 6 and a discharge passage 7 provided in the casing body 1A, respectively.

In the above configuration, the present invention includes oil pressure reducing means 11 for reducing the oil pressure of the oil leaking to the sliding contact surface between the rotor 2 and the cap 1B due to the pump action.

The means 11 for reducing the oil pressure of the leak oil
In the first embodiment shown in FIG. 1, the cap portion 1B corresponds to the rotation shaft end face 8A exposed inside the cap portion.
A small hole 12 is formed in the small hole 12, and the leak oil is discharged to the outside from the small hole 12 to reduce the oil pressure of the leak oil. The diameter of the small hole 12 is approximately φ in the case of a trochoid pump applied to a four-cycle engine of a motorcycle.
It is preferable to set it to 0.6 to φ1.0. In addition, this first
In the case of the embodiment, during the operation of the pump, the leak oil is discharged to the outside from the small holes 12, but the amount of the leak oil discharged to the outside is extremely small and may affect the pump performance. Not something. This oil is returned to the oil pan.

As the oil pressure reducing means 11 for the leak oil, the second embodiment shown in FIG. 2 has an induction recess 13 provided on the surface of the cap portion 1B so as to be continuous with the discharge side port 5. The closed space formed between the outer rotor 2A and the inner rotor 2B by rotation is
A part of the high-pressure oil pressurized immediately before communication with the oil supply port is guided to the discharge port 5 through the guide recess 13 to reduce the amount of oil leaking to the sliding contact surface between the rotor 2 and the cap 1B. .

As the oil pressure reducing means 11 for the leak oil, the third embodiment shown in FIGS. 3 and 4 has a concave portion 14 formed in the cap portion 1B corresponding to the end face 8A of the rotating shaft.
Pressure relief groove 1 that communicates with suction port 4 from recess 14
The oil leaking to the sliding contact surface between the rotor 2 and the cap portion 1B escapes from the end of the rotating shaft to the suction side port 4 via the pressure relief groove 15 and the end surface 8A of the rotating shaft.
To reduce the surface pressure.

[0022]

The present invention is embodied in the form described above and has the following effects.

The oil pressure of the oil leaking to the sliding surface between the rotor and the cap acts as a thrust force on the rotating shaft by providing means for reducing the oil pressure of the leak oil in the cap constituting the casing. And the rotational characteristics of the trochoid pump are not affected.

The means for reducing the oil pressure of the leak oil, in which a small hole is formed in the cap corresponding to the end of the rotating shaft, is excellent in workability and can be easily implemented to improve a commercially available pump. .

As a means for reducing the oil pressure of the leaked oil, a means in which a guide recess is provided on the surface of the cap portion so as to be continuous with the discharge port, a part of the pressurized high-pressure oil is directed to the discharge port first. And the amount of oil leaking to the sliding contact surface between the rotor and the cap can be reduced. In addition, since the processing of the guide concave portion on the inner surface of the cap portion can be easily performed, it can be easily performed to improve a commercially available pump.

As a means for reducing the oil pressure of the leak oil, a pressure relief groove communicating from the end of the rotating shaft to the low pressure side is provided on the cap surface, and the leakage oil to the end of the rotating shaft is released to the low pressure side to rotate. The surface pressure applied to the shaft end surface can be reduced. In addition, since it can be easily carried out with a slight processing on the inner surface of the cap portion, it can be easily carried out to improve a commercially available pump.

[Brief description of the drawings]

FIG. 1 is a side view, partially in section, showing an internal configuration of an embodiment of a trochoid pump according to the present invention.

FIG. 2 is a front view, partially in section, showing the internal configuration of an embodiment of the trochoid pump according to the present invention.

FIG. 3 is a side view showing a partial cross section of an internal configuration showing an embodiment of the trochoid pump according to the present invention.

FIG. 4 is a front view, partially in section, showing the internal configuration of an embodiment of the trochoid pump according to the present invention.

FIG. 5 is a side view showing an internal configuration of a conventional trochoid pump in a partial cross section.

FIG. 6 is a front view showing the internal configuration of a conventional trochoid pump in a partial cross section.

[Description of Signs] P Trochoid pump 1 Casing 1A Casing body 1B Cap 2 Rotor 2A Outer rotor 2B Inner rotor 3 Rotor housing 4 Inlet port 5 Outlet port 6 Inlet passage 7 Outlet passage 8 Rotating shaft 8A Rotary shaft end face REFERENCE SIGNS LIST 9 drive pin 10 support hole 11 oil pressure reduction means 12 small hole 13 guide recess 14 recess 15 pressure relief groove

Claims (4)

[Claims] 1. A trochoid pump wherein a cap portion forming a casing of the pump is provided with means for reducing oil pressure of leak oil acting in a thrust direction with respect to a rotating shaft. 2. The trochoid pump according to claim 1, wherein the oil pressure reducing means comprises a small hole having a diameter of approximately φ0.6 to φ1.0 formed in the cap portion corresponding to the end face of the rotary shaft. . 3. The trochoid pump according to claim 1, wherein the oil pressure reducing means comprises a guiding recess provided on a cap portion surface for guiding a part of the high-pressure oil pressurized by the rotor to a discharge side. . 4. The trochoid pump according to claim 1, wherein said oil pressure reducing means comprises a pressure relief groove provided on a surface of the cap portion communicating from the end of the rotating shaft to the low pressure side.