JPS63223380A - Internal gear pump - Google Patents

Abstract

PURPOSE:To improve pump efficiency, by installing an elastic body, energizing an outer rotor ranging from the space side where volumetric capacity comes to maximum in each tooth surface between the outer rotor and an inner roller to be engaged with the former toward another space side where the capacity comes to minimum, in an outer circumferential surface of the outer rotor. CONSTITUTION:An internal gear pump is constituted of the outer rotor 2, having n sheets of teeth, installed in a casing 1 free of rotation and the inner rotor 3, having (n-1) sheets of teeth, supported by a support shaft 3a free of rotation as well. And, in this case, in spaces to be formed in an interval of each tooth surface between the outer rotor 2 and the inner rotor 3, an elastic body 10 being free of expansion in vertical directions is installed in installed in the casing 1 being positioned in the upper part of a space Smax where capacity comes to maximum so as to come into contact with an outer circumferential part of the outer rotor 2. Then, the outer rotor 2 is energized in direction toward the space Smin side where capacity comes to minimum from the space Smax where it comes to maximum by this elastic body 10.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an internal gear pump having two gears (an outer multi-rotor and an inner rotor) with a difference in the number of teeth of one.

``Prior Art'' As a conventional internal gear pump of this type, those shown in FIGS. 5 to 7 are known.

In this example, the internal gear pump has an outer rotor 2 having six teeth rotatably provided in a casing l.
The inner rotor 3 is provided within the outer rotor 1 and has five teeth rotatably supported by a support shaft 3a. The space S formed between the two rotors 2 and 3 rotates around their respective rotation centers 0110. The structure is such that when it is located at a portion indicated by symbol A on a straight line passing through, its volume is minimum, and when it is located at a region indicated by symbol B, its volume is maximum.

Further, as shown in FIG. 6, a suction boat 4 for supplying fluid such as hydraulic oil into the space S is provided in the casing portion facing the end surfaces of both rotors 2 and 3, and a suction boat 4 for supplying fluid such as hydraulic oil into the space S. , and a discharge port 5 for discharging pressurized fluid within the space S are provided, respectively.

In the internal gear pump having such a configuration, fluid is sucked into the space S from the suction boat 4 as the rotors 2 and 3 rotate, and as the volume of this space S decreases, the fluid is added. It is pressurized and discharged from five discharge boats.

[Problems to be Solved by the Invention] By the way, as shown in FIG. 7, there is a body clearance d between the outer rotor 2 and the casing 1.
However, between the outer rotor 2 and the inner rotor 3,
As shown in FIG. 5, a tip clearance d2 occurs. These two clearances d, , d are unavoidable due to errors that occur during manufacturing, and cause the following problems.

That is, since the outer rotor 2 moves between the body clearances 65 during its rotation, the rotation center OI of the outer rotor 2 is not always constant and fluctuates, resulting in a decrease in pump efficiency.

Also, if the outer rotor 2 moves upward within the body clearance d+ during its rotation, the inner rotor 3
Since it is fixed by the support shaft 3a, the tip clearance d of the portion forming the space S having the maximum volume becomes large. Therefore, this tip clearance d2
However, the fluid sucked into the space S leaks, resulting in a decrease in pump efficiency.

``Object of the Invention'' The present invention was made to solve the above-mentioned problems, and an object thereof is to provide an internal gear pump with high pump efficiency.

"Means for Solving the Problems" This invention provides n-sheet (n≧3)
In an internal gear pump comprising an outer rotor having seven teeth, and an inner rotor provided within the outer rotor and having (n-1) teeth, the outer rotor has a An elastic body is provided that urges the outer rotor from the space side where the volume is the largest to the space side where the volume is the smallest among the spaces formed between the tooth surfaces of the inner rotor and the inner rotor. It is characterized by

[Embodiment] Figures 1 to 3 show an embodiment of the present invention, and the same elements as those shown in Figures 5 to 7 are given the same reference numerals and their explanations will be explained. Omitted.

The internal type gear pump shown in FIGS. 1 to 3 differs from the internal type gear pump shown in FIGS. The point is that

That is, among the spaces formed between the respective tooth surfaces of the outer rotor 2 and the inner rotor 3, the casing 1 located above the space Smax, which has the maximum volume, contains a synthetic resin that can be freely expanded and contracted in the vertical direction. An elastic body 10 made of aluminum is provided so as to come into contact with the outer circumference of the outer rotor 2.

In this state, the outer rotor 2 is urged downward in the figure by the elastic body 10 (in the direction from the space S max where the volume is maximum to the space 3 min where the volume is the minimum).

According to the internal gear pump having the above configuration, since the outer rotor 2 is urged downward by the elastic body 10, movement of the rotation center O3 of the outer rotor 2 can be prevented, and therefore the pump Efficiency can be improved.

Furthermore, since the outer rotor 2 is urged downward by the elastic body IO, the outer rotor 2 moves upward during its rotation, increasing the tip clearance d in the portion forming the space Smax. It is possible to prevent this from happening. Therefore, large leakage of fluid from this tip clearance d2 can be prevented, and pump efficiency can therefore be improved.

FIG. 4 shows another embodiment of the present invention, and this internal gear pump differs from the gear pump shown in FIGS. 1 to 3 in the shape of the elastic body.

That is, this elastic body I5 has a rotary ring +5b at a fulcrum point 0 at the lower end of a vertically extensible spring 15a.
The rotary ring 15b contacts the outer peripheral portion of the outer rotor 2 and urges the outer rotor 2 downward in the figure.

According to the internal gear pump having the above configuration, in addition to the effects of the gear pump shown in FIGS. 1 to 3, the rotating ring 15b of the elastic body 15 urges the outer rotor 2 downward while rotating. Therefore, compared to the case where the elastic body 10 is simply in contact with the outer periphery of the rotating outer rotor 2 as shown in FIGS. 1 to 3, the relationship between the outer rotor 2 and the elastic body 15 is The amount of wear at the contact portion can be reduced.

"Effects of the Invention" As explained above, according to the present invention, the space having the largest volume among the spaces formed between the respective tooth surfaces of the outer rotor and the inner rotor is provided at the outer periphery of the outer rotor. Since an elastic body is provided that urges the outer rotor from the side toward the space where the volume is the smallest, it is possible to prevent the outer rotor from moving from the space where the volume is the smallest toward the space where the volume is the largest. can. Therefore, conventionally, movement of the rotation center of the rotor is prevented,
Therefore, pump efficiency can be improved.

In addition, since the outer rotor is biased by the elastic body from the side of the space where the volume is maximum to the side where the volume is the minimum, the outer rotor is biased from the space side where the volume is the minimum to the space side where the volume is the maximum while rotating. It is possible to prevent the chip clearance from increasing in the portion that moves toward the space side and forms the space where the volume is maximum. Therefore, large leakage of fluid from this tip clearance can be prevented, and pump efficiency can therefore be improved in this respect as well.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, FIG. 1 is a cross-sectional view of the main parts of the gear pump, and FIG. 2 is a cross-sectional view along the line ■-■ in FIG. 1. 3 is an enlarged view of the inside of the chain line Y in FIG. 1, FIG. 4 is a sectional view of the main parts of a gear pump according to another embodiment of the present invention, and FIGS. 5 to 7 are examples of conventional gear pumps. 5 is a sectional view of the main parts of the gear pump, FIG. 6 is a sectional view taken along the line Vl-Vll in FIG. 5, and FIG. 7 is an enlarged view of the inside of the chain line X in FIG. It is. 1...Casing, 2...Outer rotor, 3...Inner rotor, I O, 15...
...Elastic body.

Claims (1)

[Claims] An internal gear pump comprising an outer rotor provided within a casing and having n teeth (n≧3), and an inner rotor provided within the outer rotor and having (n-1) teeth. In the outer circumferential portion of the outer rotor, among the spaces formed between the tooth surfaces of the outer rotor and the inner rotor, the outer rotor is arranged from the space side where the volume is the largest to the space side where the volume is the smallest. An internal gear pump characterized by being provided with an elastic body that biases.