JPH0744779Y2 - Trochoid type oil pump - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention prevents oil from leaking outside the pump body by returning the oil leaking from the gap between the outer rotor and the inner rotor in the rotor chamber to the oil pan. The present invention relates to a trochoid type oil pump.

[Conventional technology and its problems]

Conventionally, a trochoid type oil pump consisting of an outer rotor and an inner rotor formed on trochoid teeth is used as a pump for pumping oil to an engine lubrication system such as an automobile, and is particularly smaller than a gear type oil pump and has low noise. Because of its advantages, it is often used in general mass-produced engines. Most of the trochoidal type oil pumps are formed by an outer rotor and an inner rotor having one tooth less than that of the outer rotor, and the space between the outer rotor and the inner rotor is a suction port during one rotation of the outer rotor. The trochoidal type oil pump sucks and discharges a fluid such as oil due to these functions. By the way, the outer rotor and the inner rotor are internally provided in a rotor chamber, and when the space formed by the outer rotor and the inner rotor moves from the suction port to the discharge port, oil runs out of the space and leaves the rotor chamber. It may leak. The leaked oil accumulates in the rotary shaft accommodating chamber toward the rotary shaft of the inner rotor, and when it accumulates in the rotary shaft accommodating chamber for a predetermined amount or more, or when the leak pressure is exceeded, it leaks to the outside of the pump body from the oil seal. And the leakage pressure increases on the oil seal side, which damages the seal portion.

[Means for Solving the Problems]

Therefore, as a result of earnest studies and researches in order to solve the above-mentioned problems, the inventor has found that the invention has an annular shape around the opening of the boss hole of the circular wall surface on the rotor chamber body side of the pump body of the casing having the rotor chamber. An annular recessed step portion is formed around the opening of the fixed hole of the inner rotor which is formed with a protrusion and is housed in the rotor chamber. A trochoidal oil pump in which a leakage oil return path formed between the fixed hole of the inner rotor and the non-circular portion of the rotary shaft and the leakage oil guide section communicate with the leakage oil guide section. As a result, the oil leaking from the rotor chamber does not leak to the outside of the pump body, and the oil can be returned to the suction port or the oil pan again to prevent oil loss. Those were.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 15.

As shown in FIG. 1, the casing A is configured to be divisible by a metal material (for example, aluminum die cast),
A flat cylindrical hollow rotor chamber 1 is formed inside. The casing A is composed of two parts, a pump body A ₁ and a pump body A _2, and the pump body A ₁
A recess is formed in the pump body, and a pump cover is attached to the pump body A _1.
When A ₂ is joined, the rotor chamber 1 is formed as a flat cylindrical hollow. An outer rotor B and an inner rotor C are installed in the rotor chamber 1. Specifically, an outer rotor B provided with inner teeth and an inner rotor C provided with outer teeth mesh with each other and are eccentrically installed inside the rotor chamber 1 (see FIG. 1). A fixed hole 4 is formed in the inner rotor C, and a non-circular portion 10 of a rotary shaft 10 described later is formed.
The inner rotor C is configured to be fixed to the rotating shaft 10 through a. The outer rotor B and the inner rotor C have trochoidal teeth, and the inner rotor C has one tooth less than the outer rotor B, and when the inner rotor C makes one revolution, the outer rotor B becomes one. It is configured to rotate with a tooth delay.
In addition, the inner rotor C always contacts the tooth tops or bottoms of the outer rotor B with the tooth tips of the inner rotor C at any rotation angle, so that the tooth gaps between the adjacent tooth tips of the inner rotor C and the outer rotor B are kept. A plurality of voids s, s, ... Are formed, and while the outer rotor B and the inner rotor C rotate, the volume of each void s increases and decreases, and suction and discharge are performed.

As an element constituting the flat cylindrical hollow rotor chamber 1, a rotor chamber body side circular wall surface 1a, a rotor chamber cover side circular wall surface 1b and a circumferential wall 1c (see FIG. 1) are formed. An annular protrusion 3 is formed around the opening of the boss hole 2 at the center of 1a. Further, an annular recessed step portion 5 that is rotatably inserted into the annular protrusion portion 3 is formed on one side surface of four fixed holes of the inner rotor C provided in the rotor chamber 1. A gap between the annular protruding portion 3 and the annular concave step portion 5 is configured as a leak oil guiding portion 6. As shown in FIG. 3, the leak oil guide portion 6 has an introduction passage substantially parallel to the rotation shaft 10.
6a is formed toward the rotor chamber cover side circular wall surface 1b side from the rotor chamber body side circular wall surface 1a side. A vertical passage 6b orthogonal to the rotation axis 10 is formed from the tip of the introduction passage 6a (see FIG. 3), or the tip end of the introduction passage 6a faces the rotation axis 10 and the rotor chamber body side circular wall surface 1a is formed. An inclined passage 6c that inclines to the side may be formed (see FIG. 9). There is also an example in which the leak oil guide portion 6 is formed only by the inclined passage 6c (see FIG. 10).

The annular protruding portion 3 is formed with an annular raised portion around the opening of the boss hole 2 of the circular wall surface 1a on the rotor chamber body side, and has a trapezoidal or square cross section. More specifically, the circular wall surface 1a on the rotor chamber body side
Rise side surface 3a that is substantially perpendicular to the rotation axis 10 and is substantially parallel to the rotation axis 10, and vertical surface 3b that is substantially perpendicular to the rotation axis 10.
The vertical surface 3b extends from the tip of the rising side surface 3a toward the edge of the boss hole 2. Further, as shown in FIG. 9, instead of the vertical surface 3b which is substantially orthogonal to the axis of the boss hole 2 (substantially orthogonal to the rotating shaft 10), the tip of the rising side surface 3a goes from the tip to the inlet of the leak oil return passage 11. Thus, an inclined surface 3c that is inclined (straight or arcuate) is formed. Further, as shown in FIG. 10, the annular protrusion 3 has a substantially triangular cross section, and has only a continuous inclined surface 3c which gradually rises from the circular wall surface 1a on the rotor chamber body side toward the tip of the boss hole 2. There are also examples formed from

As shown in FIG. 8, the annular concave step portion 5 has a circumference around the fixed hole 4 on one side surface of the inner rotor C so as to be recessed inward from a side surface (a surface on which teeth are not formed). It is formed into a shape and corresponds to each embodiment of the sectional shape of the annular protrusion 3. Specifically, the inner rotor C has an inner peripheral surface 5a orthogonal to a side surface (a surface on which teeth are not formed), and a vertical bottom surface 5b facing the center of the fixed hole 4 of the inner rotor C. The vertical bottom surface 5b corresponds to the vertical surface 3b of the annular protrusion 3.

In addition, as shown in FIG. 9, there is an embodiment in which an inclined bottom surface 5c is formed at the inner end of the inner peripheral surface 5a in place of the vertical bottom surface 5b, and corresponds to the inclined surface 3c of the annular protrusion 3. To do. In addition,
As shown in FIG. 10, the inclined bottom surface 5c is formed as a linear or gentle arcuate inclined surface, and the continuous inclined surface 3c is formed.
Corresponding to.

As described above, in the pump body A ₁ in which the annular protruding portion 3 is integrally formed, the distance between the boss hole 2 provided with the annular protruding portion 3 and the rotary shaft 10 is usually about 0.2 mm to 0.5 mm. To do.

Another embodiment of the annular protrusion 3 is a pump body A _{1 in} which a ring-shaped bush member b is formed separately as shown in FIGS. 11 to 13. When the bush material b is used, the annular projection 3 integrally formed with the circular wall surface 1a on the rotor chamber body side is not formed around the boss hole 2 of the pump body A ₁ in advance. A hole larger than the boss hole 2 into which b can be fitted is bored. The portion of the bush b that protrudes from the rotor chamber body-side circular wall surface 1a becomes the annular protrusion 3. The bush material b may be used as a bearing material, and in this case, the distance from the rotating shaft 10 is about 0.05 mm.
Form inside and outside.

A suction port 7 and a discharge port 8 are formed on both left and right sides of the rotor chamber body side circular wall surface 1a of the pump body A ₁ , and port partitioning portions 9, 9 are formed between them. As shown in FIG. 14, the port partition 9 exists above and below the circular wall surface 1a on the rotor chamber body side, but the outer rotor B and the inner rotor C rotate counterclockwise in FIG. However, in the case where the suction port 7 is formed on the right side of the figure and the discharge port 8 is formed on the left side, the void portion s has the maximum volume when passing through the port partition section 9 on the upper side of the figure. Further, as shown in FIG. 15, the suction port 7 is connected to the suction port 7a, and the discharge port 8 is connected to the discharge port 8a outside the casing A, respectively. Further, although not shown, the suction port 7, the discharge port 8 and the partition portion 9 between the ports are the pump cover A ₂
It may be formed in.

The rotating shaft 10 is formed as a non-circular portion 10a for fixing the inner rotor C on one side from a longitudinal middle portion thereof. The non-circular portion 10a has a diameter larger than that of the other portion of the rotating shaft 10, and flat surfaces facing each other in parallel in the diametrical direction are formed, and the cross-section of the non-circular portion 10a has a substantially elliptical shape. There is. The through hole of the fixed hole 4 of the inner rotor C is formed to have the same cross-sectional shape as the fixed hole 4 of the rotary shaft 10, and the non-circular portion 10a is fixed to the fixed hole 4 of the fixed hole 4.
The inner rotor C rotates synchronously with the rotating shaft 10 by being inserted into. Alternatively, the inner rotor C and the rotary shaft 10 are each formed with a key groove,
The inner rotor C may be fixed to the rotary shaft 10 using a key. At the inner rotor C and the rotating shaft 10, the leak oil return path is provided so that the leak oil returns to the suction port 7a of the suction port 7 or the oil pan 12 on the engine block side.
11 are formed. There are a plurality of embodiments of the leak oil return path 11, and as shown in FIGS. 1 to 3 and 5, etc., the leak oil return path 11 is formed as a groove in the fixed hole 4 in the inner rotor C, or As shown in FIG. 6, it is formed as a groove in the non-circular portion 10a of the rotary shaft 10, or as a gap between the non-circular portion 10a and the fixed hole 4 as shown in FIG. . In the figure, O _c is an oil seal.

[Action]

First, the oil contained in the voids s, S, ... Formed by the outer rotor B and the inner rotor C in the rotor chamber 1 leaks out from the voids s, s ,. It travels between C and the circular wall 1a on the rotor chamber body side, and travels in the direction of the rotating shaft 10. Then, the leakage oil guiding portion 6 formed by the annular protruding portion 3 of the circular wall surface 1a on the rotor chamber body side and the annular concave step portion 5 of the inner rotor C.
The leak oil flows into the leak oil return path 11 by the leak oil guide portion 6. Then, it flows toward the rotor chamber body side circular wall surface 1b opposite to the rotor chamber body side circular wall surface 1a, and is returned to the suction port 7 or the external oil pan 12 or the like.

[Effect of device]

In the present invention, an annular protrusion 3 is formed around the opening of the boss hole 2 of the circular wall surface 1a on the rotor chamber body side of the pump body A ₁ of the casing A having the rotor chamber 1, and the rotor chamber 1 is internally provided with the annular protrusion 3. Around the opening of the fixed hole 4 of the inner rotor C, an annular recessed step portion 5 which can be rotationally inserted into the annular projection portion 3 is formed, and between the annular recessed step portion 5 and the annular projection portion 3 is formed. The gap is used as the leakage oil guide portion 6, and the inner rotor C is used.
First, by using the trochoidal type oil pump in which the leak oil return path 11 formed between the fixed hole 4 of the rotary shaft 10 and the non-circular portion 10a of the rotary shaft 10 and the leak oil guide portion 6 are communicated with each other, Leakage to the outside of the casing A can be prevented, and secondly, the structure is extremely simple.

To describe these effects in detail, first, when the oil contained in the space s formed by the outer rotor B and the inner rotor C leaks out from the rotor chamber 1, the oil seal O _c is changed as in the conventional case. It is introduced into the inlet opening of the leak oil return path 11 in the immediate vicinity of this point through the leak oil guide portion 6 formed on the opposite side, not on the side, thereby returning to the suction port 7 or the oil pan 12. ,
It is possible to prevent the loss of leaked oil. That is, since the leak oil guide portion 6 is located inside the fixed hole 4 of the inner rotor C, the leak oil guide portion 6 is closer to the inlet of the leak oil return path 11, and most of the leak oil is returned to the leak oil return path 11 or the like. It can be returned efficiently first. Further, the leakage pressure to the oil seal portion becomes extremely low, and there is an advantage that the seal portion can be prevented from being damaged.

Also, in the present invention, the oil leakage can be prevented only by forming the annular protrusion 3 around the opening of the boss hole 2 and correspondingly forming the annular concave step 5 on the inner rotor C. However, there is an advantage that the configuration is simple and the cost can be provided at a low cost.

If the inclined oil passage 6c is formed in the leak oil guide portion 6 toward the inlet side of the leak oil return passage 11, the leak oil will more easily flow into the leak oil return passage 11 and the leak oil return passage 11 will be returned. The effect is that it can be introduced very efficiently into the entrance opening of the passage 11.

[Brief description of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal side view of the present invention, FIG. 2 is a perspective view of an essential part of the present invention, and FIG. 3 is an enlarged sectional view of an essential part of the present invention. FIG. 4 is a perspective view of a main part of the pump body, FIG. 5 is a perspective view with a part of the inner rotor cut away, FIGS. 6 and 7 are perspective views of main parts of the rotating shaft and the inner rotor, and FIG. FIG. 9 and FIG. 10 are enlarged cross-sectional views of an essential part of another embodiment of the present invention, and FIG. 11 is a vertical cross-sectional view showing another embodiment of the present invention. FIG. 12 is an exploded perspective view of a main part of the embodiment shown in FIG.
FIG. 13 is a perspective view of an essential part of FIG. 11, FIG. 14 is a vertical sectional front view of the present invention, and FIG. 15 is a sectional view of an entire leakage prevention system using the present invention. A ...... casing, A ₁ ...... pump body, C ...... inner rotor, 1 ...... rotor chamber, 1a ...... rotor chamber body side circular wall, 2 ...... boss hole, 3 ...... annular projection, 4 ......
Fixed holes, 5: annular concave step, 6: leaking oil guiding part, 10: rotating shaft, 10a: non-circular part.

Claims (1)

[Scope of utility model registration request] 1. A pump body of a casing having a rotor chamber, wherein an annular protrusion is formed around an opening of a boss hole on a circular wall surface of the pump chamber on the rotor chamber body side. Around the opening, an annular recessed step portion that can be rotationally inserted into the annular projection portion is formed, and a gap between the annular recessed step portion and the annular projection portion serves as a leak oil guide portion,
A trochoidal type oil pump, characterized in that a leakage oil return path formed between a fixed hole of an inner rotor and a non-circular portion of a rotary shaft communicates with the leakage oil guide portion.