JP2000303965A - Trochoid pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of vibration and noise by restraining the occurrence of cavitation and fluid hammering phenomenon with a simplified, constitution and to make the life of a trochoid pump longer, and its efficiency higher. SOLUTION: A pressure adjustment means A is provided for adjusting the internal pressure of a fluid carrying chamber 22 to the pressure identical to the internal pressure of a flow path further ahead of a discharge port when the fluid carrying chamber 22 partitioned so as to be formed up between the gear part 19 of an outer rotor 17 and the gear part 20 of an inner rotor 18, is positioned so as to be closed between a suction port 11 and the discharge port. The pressure adjustment means A is so constituted as to be formed out of a pressure adjusting passage 32 communicating the side surface of the fluid carrying chamber with the flow path further ahead of the discharge port, a pressure adjusting piston 33 to be closely inserted into the pressure adjusting passage 32 so as to be freely slid, and of an energizing member keeping the pressure adjusting piston 33 at the neutral position of its slide stroke, and an excess space is interposed between the side surface of the fluid carrying chamber and the end surface of the pressure adjusting piston 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trochoid pump widely used as an oil pump for an engine.

[0002]

2. Description of the Related Art FIG. 10 is a partial longitudinal sectional view showing an example of a trochoid pump, and FIG. 11 is a view taken along the line XI-XI in FIG. The trochoid pump 1 is, for example, an oil pump attached to an engine. A pump case 2 forming an outer shell of the trochoid pump 1 is liquid-tightly covered with a case body 4 on a case body 3 and fastened and fixed with five bolts 5. Composed of
Fixing brackets 6 and 7 are formed on the case body 3 for fastening and fixing to the engine side with bolts.

A rotor chamber 8 is recessed on the case cover 4 side, and a suction port 11 and a discharge port 12 are formed on the front surface 9 of the case body 3.
3 is connected, and a discharge passage 14 is connected to the discharge port 12. The outer end of the suction passage 13 is closed by a plug 15. An outer rotor 17 and an inner rotor 18 are housed in the rotor chamber 8.

The outer rotor 17 is formed in the shape of an internal gear having a plurality of teeth 19 formed by a trochoidal curve on the inner periphery thereof, so that there is no gap in the rotor chamber 8 both radially and axially and smoothly. It is fitted rotatably. On the other hand, the inner rotor 18 is formed in an external gear shape having one less tooth portion 20 than the outer rotor 17 on its outer peripheral portion, and is pivotally supported at an eccentric position with respect to the center of the outer rotor 17 (rotor chamber 8). Pump shaft 2
1 is provided integrally with the rotation. A driving sprocket 22 is fixed to the outer end of the pump shaft 21 by a bolt 23 so as to rotate integrally therewith.

The teeth 20 of the inner rotor 18 mesh closely with the teeth 19 of the outer rotor 17, and a plurality of fluid transfer chambers 24 are defined between the teeth 18 and the teeth 20.
The volume of the fluid transfer chamber 24 changes as the outer rotor 17 and the inner rotor 18 rotate. That is,
The volume of the fluid transfer chamber 24 becomes almost zero at the position where the teeth 19 and the teeth 20 are completely engaged, expands in the section where the engagement is released, becomes maximum at the position where the engagement is completely released, and the engagement becomes complete. In the section where it starts, it shrinks.

The suction port 11 is provided so as to overlap the section where the volume of the fluid transfer chamber 24 is expanded, and the discharge port 12 is overlapped with the section where the volume of the fluid transfer chamber 24 is reduced. Provided.
When the fluid transfer chamber 24 is located between the suction port 11 and the discharge port 12, it is in a sealed state.

When the inner rotor 18 and the outer rotor 17 rotate, oil is sucked from the suction port 11 into the fluid transfer chamber 24 by the negative pressure accompanying the expansion of the volume of the fluid transfer chamber 24, and the oil is transferred to the discharge port 12 side. Here, the oil is discharged to the discharge port 12 with the contraction of the fluid transfer chamber 24. Therefore, the oil is continuously pressure-fed from the suction passage 13 to the discharge passage 14.

[0008]

However, in such a trochoid pump 1, as described above, the fluid transfer chamber 2 is provided.
When the suction port 4 is located between the suction port 11 and the discharge port 12, the sealed state is established. At this time, the oil (or another transfer fluid) sealed in the fluid transfer chamber 24 rapidly changes due to a change in the volume of the fluid transfer chamber 24. Cavitation is likely to be induced because the pressure is sequentially reduced and increased. Further, at the moment when the fluid transfer chamber 24 overlaps the discharge port 12, the high-pressure oil on the discharge port 12 (discharge passage 14) side flows backward to the fluid transfer chamber 24 side, and the fluid hammer phenomenon is likely to occur. Due to these phenomena, vibration and noise are generated, and the life of the trochoid pump 1 is shortened.

Therefore, the trochoid pump 2 shown in FIG.
7, chamfer 2 on one side of the inner rotor 18.
8 (see also FIG. 13), the fluid transfer chamber 24
Even when is located between the suction port 11 and the discharge port 12, the cavitation and fluid can be communicated slightly with the adjacent fluid transport chambers 24 to alleviate the pressure difference between the fluid transport chambers 24. A device that suppresses the occurrence of the hammer phenomenon was developed.

However, in this case, the fluid transporting chamber 24, which should be in a sealed state, can be moved from the fluid transporting chamber 2 adjacent thereto.
The oil (carrier fluid) leaks through the chamfer 28 to the pump 4 and the pump efficiency decreases, and the hydraulic pressure (hydraulic pressure) drops, and the trochoid pump 27 is made larger or the drive rotation speed is increased accordingly. And other measures are required. In addition, vibration and noise are considerably reduced by this measure, but it is not sufficient.

A trochoid pump according to the present invention has been invented in order to solve the above-mentioned problems. An object of the present invention is to prevent the occurrence of cavitation and fluid hammer phenomena by a simple structure to thereby suppress the generation of vibration and noise. The purpose of the present invention is to provide a trochoid pump with a longer life and higher efficiency.

[0012]

In order to achieve the above object, a trochoid pump according to the present invention comprises a tooth portion of an outer rotor formed in the shape of an internal gear and an external gear shape. A trochoid pump that draws fluid from a suction port and discharges the fluid to a discharge port in accordance with a change in volume of a fluid transfer chamber defined between the inner rotor and the tooth portion of the inner rotor. And a pressure adjusting means for adjusting the internal pressure of the fluid transfer chamber to be equal to the pressure in the flow path after the discharge port when the chamber is sealed between the discharge port and the discharge port.

When such a pressure adjusting means is provided, when the fluid transfer chamber is in a closed state, the internal pressure of the fluid transfer chamber is adjusted to be equal to the pressure in the flow path after the discharge port. The pressure of the carrier fluid contained in the container does not change rapidly, and cavitation is prevented from occurring.
In addition, at the moment when the fluid transfer chamber overlaps the discharge port, the transfer fluid does not flow backward from the discharge port side to the fluid transfer chamber side.

Further, the trochoid pump according to the present invention comprises:
As described in claim 2, in the configuration of claim 1,
The pressure adjusting means, a pressure adjusting passage that communicates the side surface of the sealed fluid transfer chamber between the suction port and the discharge port to a flow path after the discharge port, and densely in the pressure adjusting passage, and A pressure adjusting piston slidably inserted and an urging member for keeping the pressure adjusting piston at a neutral position of its sliding stroke are provided.

According to this configuration, when the volume of the sealed fluid transfer chamber located between the suction port and the discharge port changes and the internal pressure of the fluid transfer chamber changes, the pressure adjusting piston is moved by the corresponding amount. It slides in the pressure adjustment passage, and the internal pressure of the fluid transfer chamber is adjusted to be equal to the pressure in the flow path after the discharge port. And the movement of the pressure adjustment piston is ensured by the urging member, and the pressure adjustment is performed smoothly.

Further, in the trochoid pump according to the present invention, as described in claim 3, in the structure of claim 2, an extra space is formed between a side surface of the fluid transfer chamber and an end surface of the pressure adjusting piston. did. With this configuration, when the internal pressure of the fluid transfer chamber is reduced, the pressure adjustment piston can smoothly move toward the fluid transfer chamber, and there is no concern that the pressure adjustment piston touches the outer rotor or the inner rotor. Pressure is smoothly adjusted.

According to a fourth aspect of the present invention, in the trochoid pump according to the second aspect of the present invention, the area of the end face of the pressure adjusting piston opposite to the fluid transport chamber is changed to the fluid transport chamber side. Larger than the area of the end face. As a result, the internal pressure of the fluid transfer chamber is maintained higher than the pressure in the flow path after the discharge port by an amount corresponding to the end face area ratio of the pressure adjusting piston. Is discharged to the discharge port side vigorously, and the efficiency of the trochoid pump is increased.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of a trochoid pump according to the present invention. In the trochoid pump 31, reference numerals 2 to 24 are used.
The configuration and operation of the portion indicated by are the same as those of the conventional trochoid pump 1 shown in FIGS.

The trochoid pump 31 is provided with a pressure adjusting means A. When the fluid transfer chamber 24 is located between the suction port 11 and the discharge port 12 and is sealed, the pressure adjusting means A adjusts the internal pressure of the fluid transfer chamber 24 to a flow path after the discharge port 12, for example, the flow path of the discharge passage 14. This is a means for adjusting the internal pressure to the same level as that of the internal pressure.

First, on the case body 3 side of the pump case 2, a pressure adjusting passage 32 is formed as shown in FIGS. The pressure adjustment passage 32 is connected to the discharge passage 14 from the front 9 (rotor chamber 8) side of the case body 3.
It is formed in a through hole shape penetrating to the side, and its position is such that when the fluid transfer chamber 24 is located between the suction port 11 and the discharge port 12, the pressure adjusting passage 32 overlaps the fluid transfer chamber 24. I have.

Preferably, as shown in FIGS. 5 (A) to 5 (C), immediately after the overlap between the fluid transfer chamber 24 and the suction port 11 is completed, the fluid transfer chamber 24 and the pressure adjusting passage 3 are closed.
Pressure adjusting passage 32 so that the overlap with
Position. Thereby, the fluid transfer chamber 24 is located between the suction port 11 and the discharge port 12 and is sealed, and at the same time, the fluid transfer chamber 24 communicates with the discharge passage 14 via the pressure adjustment passage 32.

As shown in FIG. 3A, the pressure adjusting passage 32 is formed as a stepped hole whose inner diameter changes in three steps, and the inner diameter of a portion 32a opened to the discharge passage 14 side is the smallest.
The inner diameter of the middle 32b is one step wider than the 32a,
The inside diameter of the portion 32c opening toward the front surface 9 (rotor chamber 8) is one step larger than that of the portion 32b. Then, the pressure adjusting piston 33 is densely provided in the pressure adjusting passage 32,
And it is slidably inserted.

As shown in FIG. 3 (B), the pressure adjusting piston 33 is formed in a round bar shape having a flange portion 33b formed at an intermediate portion.
2, and the flange portion 33b is inserted into the 32b portion of the pressure adjustment passage 32. An annular piston guide 34 is press-fitted into the 32c portion of the pressure adjustment passage 32 from the rotor chamber 8 side, and the other half body 33c of the pressure adjustment piston 33 is slidably inserted into the center hole of the piston guide 34.

Further, coil springs 35 and 36 are elastically mounted before and after the flange portion 33b of the pressure adjusting piston 33. These coil springs 35, 36
When the trochoid pump 31 is stopped, the pressure adjusting piston 33 is kept at the neutral position of its sliding stroke by the urging forces of the coil springs 35 and 36.

The area of the end face 33d on the rotor chamber 8 side of the pressure adjusting piston 33 and the area of the end face 33e on the discharge passage 14 side are set to be the same, but as shown in FIG. It may be set slightly larger than the area of 33d. The end face 33d is located on the front surface 9 of the case body 3.
(The outer end surface of the piston guide 34) is retracted to the back side, whereby an extra space 37 is formed between the end surface 33d of the pressure adjusting piston 33 and the side surface (the front surface 9) of the fluid transfer chamber 24.

The pressure adjusting means A is configured as described above. The operation of the trochoid pump 31 by providing such pressure adjusting means A is as follows.

First, as shown in FIG. 5A, when the overlap between the fluid transfer chamber 24 and the suction port 11 is completed and the fluid transfer chamber 24 is positioned between the suction port 11 and the discharge port 12, The fluid transfer chamber 24 is sealed. At this time,
The opening of the pressure adjustment passage 32 on the rotor chamber 8 side is closed by the teeth 19 of the outer rotor 17, and the pressure (discharge pressure) in the discharge passage 14 is applied to the end face 33 e of the pressure adjustment piston 33. Therefore, the internal pressure of the surplus space 37 is pressurized by the pressure adjusting piston 33 and becomes equal to the discharge pressure.

Immediately after this, as shown in FIG. 5B, when the fluid transfer chamber 24 starts to overlap the pressure adjusting passage 32, the internal pressure (discharge pressure) of the surplus space 37 propagates to the fluid transfer chamber 24, The internal pressure of the fluid transfer chamber 24 becomes equal to the discharge pressure. At this time, for example, when the volume of the fluid transfer chamber 24 is reduced and the internal pressure of the fluid transfer chamber 24 is increased, the pressure adjusting piston 33 slides toward the discharge passage 14 side, and
4 is released, and conversely, when the volume of the fluid transfer chamber 24 is increased and the internal pressure of the fluid transfer chamber 24 is reduced, the pressure adjusting piston 33 slides toward the fluid transfer chamber 24 and the pressure is increased. The decline is compensated for.

As described above, in the section where the fluid transfer chamber 24 is located and sealed between the suction port 11 and the discharge port 12, the internal pressure of the fluid transfer chamber 24 is reduced by the slide of the pressure adjusting piston 33 after the discharge port 12. The pressure is adjusted to be equal to the pressure in the flow path, so that the oil being transported does not undergo a rapid pressure reduction or pressure increase due to a change in the volume of the fluid transport chamber 24, and cavitation is prevented from occurring.

Then, as shown in FIG. 5C, when the fluid transfer chamber 24 overlaps the discharge port 12 and discharges the oil, the oil having the same pressure as the pressure after the discharge port 12 becomes the fluid. Discharge port 1 from transfer chamber 24
2 from the discharge port 12 to the fluid transfer chamber 2
The high-pressure oil does not flow back to 4 and the occurrence of the fluid hammer phenomenon is also prevented.

Since the cavitation and the fluid hammer phenomenon are prevented in this way, vibration and noise during operation of the trochoid pump 31 are reduced, and the life of the trochoid pump 31 is extended. Further, there is no concern that the pump efficiency is reduced.

Here, the pressure adjusting means A includes a pressure adjusting passage 32, a pressure adjusting piston 33, and a piston guide 3.
4 and the coil springs 35 and 36, the configuration is very simple, so that a significant increase in manufacturing cost does not occur. Moreover, the end surface 33 of the pressure adjusting piston 33
Since the excess space 37 is formed on the d side, when the internal pressure of the fluid transfer chamber 24 is reduced, the pressure adjusting piston 3
3 can smoothly move to the fluid transfer chamber 24 side, and there is no concern that the pressure adjusting piston 33 interferes with the outer rotor 17 or the inner rotor 18, and the internal pressure of the fluid transfer chamber 24 can be adjusted smoothly.

As shown in FIG. 4, when the area of the end face 33e of the pressure adjusting piston 33 is made slightly larger than the area of the end face 33d, the internal pressure of the sealed fluid transfer chamber 24 increases the discharge pressure in the discharge passage 14. The pressure is set to be slightly higher than the pressure, so that when the fluid transfer chamber 24 overlaps the discharge port 12
Side, the backflow of oil from the discharge port 12 is more effectively prevented, and the trochoid pump 3
1 can be improved.

As shown in FIGS. 6A and 6B,
The piston guide 34 may be replaced with a press-fitting type by screw fastening instead of a press-fitting type. Here, the piston guide 34 has a hexagonal hole, and the inside of the hexagonal hole 38 is applied to an extra space. Thus, the piston guide 34
Is detachable, the pressure adjusting piston 33 and the coil springs 35 and 36 can be easily overhauled and cleaned, and the maintainability is greatly improved.

FIGS. 7 to 9 show a second embodiment of the trochoid pump according to the present invention. The trochoid pump 41 includes a pump case 44 including a case main body 42 and a case cover 43. A rotor chamber 45 is recessed on the case main body 42 side, and a suction port 46 and a discharge port 47 are adjacent to the rotor chamber 45. Formed and suction port 46
Is provided with a suction passage 48, and the discharge port 47 is provided with a discharge passage 49.
But they are connected. FIG. 7 shows the case cover 43.
Is shown in a removed state.

An outer rotor 51 and an inner rotor 52 are densely and rotatably provided in the rotor chamber 45, and a case cover 43 is provided so as to close the rotor chamber 45.
Are liquid-tightly mounted and fastened and fixed with five screws 53.
Then, with the rotation of the pump shaft 54, the inner rotor 5
When the outer rotor 51 and the outer rotor 51 are driven to rotate, a carrier fluid (oil or the like) is sucked from the suction port 46 into the fluid carrier chamber 55 defined between the outer rotor 51 and the inner rotor 52, and the discharge port 47 side. Is discharged.

In the trochoid pump 41, pressure adjusting means B is provided on the case cover 43 side. The pressure adjusting means B includes a pressure adjusting passage 56 and a pressure adjusting piston 5.
7 and coil springs 58 and 59 as urging members
, A piston guide 60 and a circlip 61. The pressure adjusting passage 56 extends along the surface direction of the case cover 43, and communication passages 62, 63 near both ends thereof.
Are formed. The communication path 62 is connected to a section between the suction port 46 and the discharge port 47, and the communication path 63 is connected to the discharge port 47.

One end of the pressure adjusting passage 56 is closed by a removable plug 64, and a pressure adjusting piston 57 is held in a step formed in the pressure adjusting passage 56 in the same manner as in the first embodiment. Springs 58, 59
As a result, the slide stroke is kept at the neutral position. The piston guide 60 is inserted into the pressure adjusting passage 56 and is positioned by the circlip 61.
By removing the circlip 61 and the piston guide 60, the pressure adjusting piston 57 and the coil springs 58 and 59 can be overhauled and cleaned.

The operation and effect of the provision of the pressure adjusting means B are the same as those of the first embodiment. That is, the fluid transfer chamber 55 is provided with the suction port 46 and the discharge port 47.
When closed, the internal pressure of the fluid transfer chamber 55 is kept equal to the internal pressure of the discharge port 47 to prevent cavitation, and the fluid transfer chamber 55 is connected to the discharge port 4.
At the time of overlapping with 7, the backflow of the carrier fluid is prevented, and the occurrence of the fluid hammer phenomenon is prevented. Therefore, with a very simple configuration, vibration and noise can be reduced, and the life of the trochoid pump 41 can be extended.

[0040]

As described above, according to the trochoid pump according to the present invention, the occurrence of cavitation and fluid hammer phenomena can be reliably prevented by a simple structure to prevent the generation of vibration and noise. Long life and high efficiency can be achieved.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of a trochoid pump according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

3A is a diagram illustrating a pressure adjustment passage, and FIG. 3B is a diagram illustrating a pressure adjustment piston.

FIG. 4 is a sectional view showing another embodiment of the pressure adjusting means.

FIG. 5 is a diagram showing the operation of the trochoid pump in the order of (A), (B), and (C).

FIG. 6A is a cross-sectional view showing another embodiment of the pressure adjusting means, and FIG. 6B is a view taken on line VIB of FIG.

FIG. 7 is a view showing a second embodiment of the trochoid pump according to the present invention with a case cover removed.

FIG. 8 is a view showing a second embodiment of the trochoid pump according to the present invention with a case cover attached.

FIG. 9 is a sectional view taken along the line IX-IX in FIG. 8;

FIG. 10 is a partial longitudinal sectional view showing an example of a trochoid pump according to a conventional technique.

FIG. 11 is a view taken along the line XI-XI in FIG. 10;

FIG. 12 is a diagram showing another example of a trochoid pump according to the related art.

13A is a front view of the inner rotor shown in FIG. 12, and FIG. 13B is a cross-sectional view taken along line XIIIB-XIIIB of FIG.

[Explanation of symbols]

 Reference Signs List 11 suction port 12 discharge port 13 suction passage 14 discharge passage 17 outer rotor 18 inner rotor 19, 20 teeth 21 pump shaft 24 fluid transfer chamber 31 trochoid pump 32 pressure adjustment passage 33 pressure adjustment piston 33d, 33e end face of pressure adjustment piston 34 Piston guides 35, 36 Coil springs as urging members 37 Extra space A Pressure adjusting means

Claims (4)

[Claims] 1. A suction port according to a change in volume of a fluid transfer chamber defined between a tooth portion of an outer rotor formed in an internal gear shape and a tooth portion of an inner rotor formed in an external gear shape. In the trochoid pump which sucks fluid and discharges it to the discharge port, when the fluid transfer chamber 24 is located and sealed between the suction port 11 and the discharge port 12, the internal pressure of the fluid transfer chamber 24 is reduced to the discharge port 12. A trochoid pump comprising a pressure adjusting means A for adjusting the pressure to be equal to the pressure in the subsequent flow path. 2. The pressure adjusting means A is connected to a suction port 11
A pressure adjusting passage 32 for communicating the side surface of the sealed fluid transfer chamber 24 located between the discharge port 12 with the flow path after the discharge port 12, and tightly and slidably in the pressure adjusting passage 32. A pressure adjusting piston 33 to be inserted,
The trochoid pump according to claim 1, further comprising an urging member (35, 36) for keeping the pressure adjusting piston 33 at a neutral position of its slide stroke. 3. An extra space 37 between a side surface of the fluid transfer chamber 24 and an end surface 33d of the pressure adjusting piston 33.
The trochoid pump according to claim 2, wherein a trochoid pump is formed. 4. The trochoid pump according to claim 2, wherein an area of an end face 33e of the pressure adjusting piston 33 opposite to the fluid transfer chamber 24 is larger than an area of an end face 33d of the pressure transfer piston 33 on the side of the fluid transfer chamber 24.