JPH1030578A - Gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent working fluid from leaking out of the inside of a gear pump which handles water as the working fluid, and improve pump efficiency. SOLUTION: In this pump, a seal plate 12 is made to face one side of a driving gear 3 and a driven gear 4 inside a gear chamber 10, a rubber seat 13 is overlapped on its outside, and a rib 12a which shuts down discharge side and suction side is fitted onto the non-gear surface of the seal plate 12. A compliance mechanism is also fitted, which presses the seal plate 12 against a gear side surface through pump discharge pressure led to the back surface of the seal plate 12, and by preventing leakage from occurring out of the inside of the pump, it is possible to improve pump efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump used as a high-pressure water pump, a self-priming pump, a high-pressure washing pump, and a high-pressure filtration pump in which a working fluid is water.

[0002]

2. Description of the Related Art Conventionally, gear pumps have been developed as pumps for hydraulic equipment using a working fluid as oil. However, when the working fluid is water, problems such as burning are caused due to the non-lubricating nature of water. It is easy and its spread is late. However, in recent years, taking advantage of its self-priming performance, it has been used in the field of water supply pumps for ice machines for home electric refrigerators and as a washing pump for sanitary washing machines in toilets, instead of the Hugal pump. I have.

As a first example of the prior art, Japanese Patent Laid-Open No.
The gear pump disclosed in Japanese Patent Publication No. 57 will be described. FIG. 11 is an exploded perspective view of a conventional gear pump, FIG. 12 is a plan sectional view of a gear portion of the gear pump, and FIG.
It is KK side sectional drawing of.

As shown in the figure, a drive gear 103 is provided in a gear chamber 110 formed by a gear case 101 and a gear cover 102.
And a driven gear 104 are incorporated. The drive gear 10
3 is driven by a drive shaft 105 of a motor 120, and a driven gear 104 that meshes with and rotates with a drive gear 103 is supported by a driven shaft 106. The space between the gear case 101 and the gear cover 102 is sealed by an O-ring 107,
The through hole of the gear cover 102 of the drive shaft 105 is shaft-sealed by an oil seal 108. Gear case 101
Includes a discharge chamber 110a and a suction chamber 110b of the gear chamber 110.
A discharge port 101b and a suction port 101a are formed in communication with the
0 with an attachment screw 109.

[0005] In the gear pump configured as described above, the driving gear 103 and the driven gear 104 mesh with each other during operation.
When rotating in the direction of the arrow in FIG.
3 and 104, the suction chamber 1 through the suction port 101a.
It is taken into 10b and sent to the discharge chamber 110a. In the discharge chamber 110a, the pressure becomes high due to the pump load, and
It is exhaled from 1b.

Next, a second conventional example will be described with reference to an exploded perspective view of a gear pump of another conventional example shown in FIG. 14 and a sectional side view of the same gear pump shown in FIG.

This conventional gear pump has a drive gear 103.
Gear case 1 having a seal plate 111 straddling the driven gear 104 and pressed against a gear side surface by a wave washer 115, and having an opening adapted to the shape thereof.
01 is stored in the opening. The gear cover 10
A plate gap 110c formed by the second and seal plates 111 communicates with the discharge chamber 110a.

In the gear pump constructed as described above, the seal plate 111 is pressed against the gear side surface by the wave washer 115 when the pump is started, but the pump discharge pressure of the discharge chamber 110a is conducted to the plate gap 110c during the operation of the pump. As a result, the seal plate 111 is pressed against the side surface of the gear and brought into a sliding contact state. By guiding the discharge pressure during the operation of the pump to the side opposite to the gear of the seal plate 111, the resultant force of the pressing force and the repulsive force is automatically adjusted even when the pump load changes, and maintains an appropriate magnitude. It will have a compliance mechanism. With this mechanism, most of the internal leakage of the gear pump is eliminated, the sliding resistance on the gear side is reduced, and high pump efficiency is obtained.

[0009]

In the first conventional example, when the gears 103 and 104 rotate in the direction of the arrow in FIG. 12, water taken in the gear chamber 110b between the teeth of the gears 103 and 104 is removed. Opened in the gear chamber 110a, the pressure increases in response to the pump load and becomes high. Therefore, as shown in FIG.
In the gap between the gear side surface and the gear case 101 and the gear cover 102 toward the low pressure of 01a, leakage inside the pump occurs as shown by an arrow in the figure, and the pump efficiency is remarkably reduced particularly in a high pressure operation region where a pump load is large.

In the second example, as a means for solving the problem as in the first example, the above-described compliance mechanism is employed in a conventional gear pump in which a working fluid such as a hydraulic fluid is oil. In a gear pump in which the fluid is water, since water does not have lubricating properties, it is necessary to employ a sliding material having a small frictional resistance and a self-lubricating property between the seal plate 111 and the two gears 103 and 104. On the seal plate 111 side, JP-A-4-7628
There is a technology that employs a Teflon resin sheet disclosed in Japanese Patent Application Publication No. 1 (1994), but when the above-described compliance mechanism is combined, if a sliding material having self-lubricating properties is not used on the side surface of the gear material, the gear teeth can be removed. Since the Teflon resin sheet is shaved during rotation at the part, the life performance is very short.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned conventional problems, and an object of the present invention is to provide a gear pump in which a working fluid is water.

[0012]

To achieve the above object, the present invention provides a gear pump using water as a working fluid,
A seal plate in which a seal plate, a drive gear and a driven gear, a seal plate, and a rubber sheet are sequentially arranged in a gear chamber, and a seal plate in which a rubber sheet is superimposed on the back side opposite to the gear side, has a discharge high pressure side of the gear chamber and suction on the back side. The gear pump has a rib for dividing the low pressure side and a means for applying a high pressure on the discharge side to the back surface of the seal plate.

According to the present invention, during operation of the pump, the seal plate is pressed against the gear side surface by the guided pump discharge pressure, and internal leakage of water from the high pressure on the pump discharge side to the low pressure on the suction side along the gear side surface. Is minimized, and leakage from the high pressure on the pump discharge side to the low pressure on the suction side along the anti-gear surface of the seal plate at the rib pressure contact portion is sealed, thereby improving the pump efficiency.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a gear pump using water as a working fluid, wherein a seal plate is provided in a gear chamber, a drive gear and a driven gear made of a material having a low frictional resistance, and a friction gear. A seal plate having a gear-side surface with low resistance and a rubber sheet are sequentially arranged, and a seal plate with a rubber sheet superimposed on the back side opposite to the gear side is restrained with the rubber sheet in the gear chamber and pressed against the side surface of the gear. The gear pump has a function of reducing sliding resistance during pump operation and increasing pump efficiency.

According to a second aspect of the present invention, in the gear pump according to the first aspect, a seal plate in which a rubber sheet is overlapped on a back surface opposite to the gear side is provided with a discharge high pressure side of a gear chamber on the back surface. It has a rib that separates the suction low pressure side,
A means for applying a high pressure on the discharge side is provided on the back surface of the seal plate, and the rib of the seal plate and the rubber sheet of the elastic body are restrained and pressed in the gear chamber. The seal plate is pressed against the gear side surface, and during the operation of the pump, the seal plate is similarly pressed against the gear side surface by the guided pump discharge pressure, and the pump discharge side high pressure along the gear side surface is reduced to the suction side low pressure. Internal leakage of water to the pump is minimized, and leakage from the high pressure on the pump discharge side to the low pressure on the suction side along the anti-gear surface of the seal plate is sealed at the rib pressure contact part, reducing leakage loss during high pressure operation. It has the effect of doing.

According to a third aspect of the present invention, in the gear pump according to the second aspect, the pump has a plurality of ribs, and the pump discharge pressure guided to the back surface of the seal plate leaks to the suction side. The force that presses the seal plate against the gear side surface approximately matches the repulsion force due to the leak pressure that tries to separate the seal side surface of the gear and the line of action, and suppresses the moment of the seal plate. The resultant is formed so as to always act in the direction of pressing the seal plate against the side surface of the gear with a minimum necessary resultant force. A plurality of ribs on the opposite gear surface of the seal plate and a rubber sheet of an elastic body are formed in the gear chamber. When the pump is started, the seal plate is pressed against the side of the gear when the pump is started. Pump discharge pressure is a plurality of ribs derived capital may form a stepwise disturbance while pressure distribution from leaking along the counter gear surface of the seal plate to the suction side,
The force that presses the seal plate against the gear side surface substantially matches the repulsion force due to the leakage pressure that tries to separate the seal side surface of the gear and the line of action, and suppresses the moment of the seal plate. It acts in the direction in which the seal plate is always pressed against the gear side surface within the range, has the effect of eliminating unnecessary wear occurring between the gear side surface and the seal plate, extending the life, and maintaining high pump efficiency.

According to a fourth aspect of the present invention, in the gear pump according to the first aspect, the rubber sheet has a rib on a surface on the seal plate side for separating a high pressure side of the discharge and a low pressure side of the gear chamber. A means for applying high pressure on the discharge side is provided on the back surface of the sheet plate from the gap between the rubber sheet and the seal plate. The ribs of the elastic rubber sheet and the sheet plate are restrained by pressure in the gear chamber. When the pump is started, the seal plate is pressed against the side surface of the gear by the repulsive force. During the operation of the pump, the seal plate is pressed against the side surface of the gear by the pump discharge pressure guided, and the seal plate is pressed along the side surface of the gear. Internal leakage of water from high pressure on the pump discharge side to low pressure on the suction side is minimized, and the pump discharge side along the opposite gear surface of the seal plate at the rib pressure contact part Sealing the leak to the low pressure of the suction side from the pressure, an effect that reduces the leakage loss during high pressure operation.

According to a fifth aspect of the present invention, in the gear pump according to the fourth aspect, the pump has a plurality of ribs, and the pump discharge pressure guided to the back surface of the seal plate leaks to the suction side. The force that presses the seal plate against the gear side surface approximately matches the repulsion force due to the leak pressure that tries to separate the seal side surface of the gear and the line of action, and suppresses the moment of the seal plate. The ribs are formed so as to always act in the direction of pressing the seal plate against the gear side surface with the minimum resultant force, and the plurality of ribs and the seal plate on the side of the seal plate of the elastic rubber sheet are formed in the gear chamber. The seal plate is pressed against the gear side when the pump is started by this repulsive force. The plurality of ribs of the rubber sheet form a pressure distribution while gradually preventing the guided pump discharge pressure from leaking to the suction side along the anti-gear surface of the seal plate, thereby forming a seal plate on the gear side surface. The pressing force almost matches the repulsion force due to the leak pressure that tries to separate the seal plate on the gear side surface and the line of action, and suppresses the moment of the seal plate. In the direction of pressing, eliminating unnecessary wear occurring between the gear side surface and the seal plate, extending the life and maintaining high pump efficiency.

According to a sixth aspect of the present invention, in the gear pump according to the first or second aspect, the seal plate having a small frictional resistance is formed of any one of a polyacetal resin, a polyphenylene sulfide resin, and a polyphenylene ether resin. In this case, the sliding resistance between the gear side surface and the seal plate during the operation of the pump is very small, and the pump efficiency is improved.

According to a seventh aspect of the present invention, in the gear pump according to any one of the first, second, and sixth aspects, the seal plate having a small frictional resistance is made of 4-hooker ethylene resin on the gear side surface. This configuration is formed by coating. This configuration also has the effect of extremely reducing the sliding resistance between the gear side surface and the seal plate during the operation of the pump, and increasing the pump efficiency.

According to an eighth aspect of the present invention, in the gear pump according to any one of the first to second aspects, the seal plate having a small frictional resistance has a surface roughness of 0.8S to 6S. .3S, which also has the effect of greatly reducing the sliding resistance between the gear side surface and the seal plate during pump operation and increasing pump efficiency.

Hereinafter, a gear pump according to an embodiment of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is an exploded perspective view of a gear pump according to Embodiment 1 of the present invention, FIG. 2 is a sectional plan view of a gear portion of the gear pump, and FIG. 4 is FIG.
5 is a perspective view of a gear cover of the gear pump, FIG. 6 (a) is a plan view of a seal plate showing a rib shape of the gear pump, and FIG. 6 (b) is a seal plate having a plurality of ribs. It is a top view.

As shown in the figure, in a gear chamber 10 formed by a gear case 1 and a gear cover 2, a seal plate 1 made of a material having a smaller frictional resistance in order from the motor 20 side.
1. A drive gear 3 and a driven gear 4 also made of a material having a small frictional resistance, a seal plate 12 made of a material having a small frictional resistance, and a rubber sheet 13 as an elastic body are stacked. The drive gear 3 is fixed to a drive shaft 5 of a motor 20, and a driven gear 4 that meshes with the drive gear 3 and rotates is supported by a driven shaft 6. Gear case 1 and gear cover 2 are O
The drive shaft 5 is sealed by a ring 7, and a through hole of the gear case 1 of the drive shaft 5 is sealed by an oil seal 8. The gear case 1 is formed with a discharge port 1b and a suction port 1a which are respectively communicated with a discharge chamber 10a and a suction chamber 10b of the gear chamber 10, and is mounted between the gear cover 2 and the motor 20 while being held therebetween. It is fixed with screws 9. And
A rib 12a protrudes from the side opposite to the gear of the seal plate 12 on which the rubber sheet 13 is overlapped so as to separate the high pressure of the discharge chamber 10a and the low pressure of the suction chamber 10b. Further, a cutout 2a for guiding the high pressure of the discharge chamber 10a to the opposite gear surface of the seal plate 12 is formed inside the gear cover 2.

Here, the seal plates 11 and 12
Is made of SUS and its anti-gear surface is coated with 4 hooker ethylene resin or the whole is polyacetal resin,
Either a polyphenylene sulfide resin or a polyphenylene ether resin is used, or the surface of the gear is polished to a roughness of 0.8S to 6.3S to reduce the frictional resistance to the side surface of the gear.

In the gear pump configured as described above, one of the seal plate 12 and the rubber sheet 13 is
Within the seal plate, and the seal plate 12
The rubber sheet 13 is pressed against the side surface of the gear in the vicinity of the suction chamber 10b due to the presence of the rib 12a. When the operation is started, the driving gear 3 and the driven gear 4 mesh with each other and rotate in the direction of the arrow in FIG. 2, and water is taken into the suction chamber 10b through the suction port 1a by the teeth of the gears 3 and 4, and It is sent to the discharge chamber 10a. In the discharge chamber 10a, a high pressure is applied by the pump load, and the discharge is performed from the discharge port 1b. At this time, the pump discharge pressure of the discharge chamber 10a is
As shown in FIG. 5, the seal plate 12 is formed inside the gear cover 2 and with the notch 2a corresponding to the gear meshing portion.
Of the rubber sheet 13 (see FIG. 4), the seal plate 12 is pressed against the side surface of the gear by the pump discharge pressure on the rear surface, and the drive gear 3 and the driven gear 4 It is always in a sliding state with respect to the seal plate 12. On the other hand, the gap 14 on the side opposite to the gear of the seal plate 12 is divided by the rib 12a, and the discharge chamber 10a
Of high-pressure water leaks into the low-pressure section of the suction chamber 10b. Therefore, no internal leakage occurs.

When the pressure difference between the discharge chamber 10a and the suction chamber 10b is too large to seal sufficiently, as shown in FIG. 6B, a plurality of ribs 12b are further added to form a plurality of ribs. The difference is reduced stepwise to reduce the burden per line.

The seal plates 11 and 12 are made of S
It is made of US and its anti-gear surface is coated with 4-hooker ethylene resin, the whole is made of polyacetal resin, polyphenylene sulfide resin or polyphenylene ether resin, or its anti-gear surface roughness is set to 0. 8S to 6.3S, and the frictional resistance to the gear side is reduced, so that when pressed against the gear side, the drive gear 3 and the driven gear 4 can rotate without any trouble, and the seal plates 11, 12 are cut off. Nor.

(Embodiment 2) FIG. 7 is an exploded perspective view of a gear pump according to Embodiment 2 of the present invention, and FIG. 8 is a plan view of a seal plate showing a rib shape in the gear pump.

In the gear pump according to the second embodiment,
The difference from the gear pump of the second embodiment resides in that ribs 12c for forming a plurality of complicated pressure distributions project on the seal plate 12 as shown in the figure.

In this configuration, when the pump is started, the seal plate 12 is pressed against the gear side surface by the rubber sheet 13. When the operation is started, the ribs 12c of the seal plate 12 form a pressure distribution while gradually preventing the guided pump discharge pressure from leaking to the suction side along the anti-gear surface of the seal plate 12. The force for pressing the seal plate 12 against the gear side surface thereby matches the repulsion force due to the leakage pressure that tends to separate the seal side surface on the gear side surface with the line of action, thereby suppressing the moment of the seal plate 12 and the resultant force is a rib. 12c
And acts in the direction of pressing the seal plate 12 against the gear side surface with a minimum necessary value within a range that can be accommodated by the shape of. For this reason, the amount of sliding wear and sliding resistance between the seal plate 12 and the side surface of the gear can be intentionally suppressed to the minimum necessary.

(Embodiment 3) FIG. 9 is an exploded perspective view of a gear pump according to Embodiment 3 of the present invention.

The difference between the gear pump according to the third embodiment and the gear pump according to the first embodiment is that a rib 13a is provided on the surface of the rubber sheet 13 on the seal plate side instead of the opposite gear surface of the seal plate 12 as shown in the figure. It is that it protruded.

The ribs 13a have the same function as the ribs 12a on the opposite gear surface of the seal plate 12 of the first embodiment.

(Embodiment 4) FIG. 10 is an exploded perspective view of a gear pump according to Embodiment 4 of the present invention.

The difference between the gear pump of the fourth embodiment and the gear pump of the second embodiment is that the seal plate 12
The rib 13b protrudes from the rubber sheet 13 as shown in FIG.

The rib 13b of the rubber sheet 13
Has the same function as the rib 12b on the opposite gear surface of the seal plate 12 of the second embodiment.

[0037]

As is apparent from the above description, the present invention relates to a gear pump using water as a working fluid, wherein a seal plate made of a material having a small frictional resistance and a drive gear made of a material having a small frictional resistance are provided in a gear chamber. And a driven gear, a seal plate made of a material having a small frictional resistance and a rubber sheet are sequentially arranged, and a seal plate in which a rubber sheet is superimposed on the back side opposite to the gear side has a discharge high pressure side of the gear chamber and suction on the back side. Since the gear pump has a rib for separating the low pressure side and a means for applying a high pressure on the discharge side on the back surface of the seal plate, the pump can be operated smoothly, and the seal plate is guided during the operation of the pump. The pump discharge pressure is pressed against the gear side, minimizing internal leakage of water from the high pressure on the pump discharge side along the gear side to the low pressure on the suction side, One, to seal the leaks from the high pressure of the pump discharge side along the counter gear surface of the seal plate in the rib contact portion to the low-pressure suction side, it has the effect of improving the pump efficiency.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a gear pump according to a first embodiment of the present invention.

FIG. 2 is a sectional plan view of a gear portion of the gear pump.

FIG. 3 is a sectional view taken along the line KK of FIG. 2;

FIG. 4 is an enlarged sectional view of a part P in FIG. 3;

FIG. 5 is a perspective view of a gear cover of the gear pump.

6A is a plan view of a seal plate showing a rib shape of the gear pump, and FIG. 6B is a plan view of a seal plate having a plurality of ribs.

FIG. 7 is an exploded perspective view of a gear pump according to a second embodiment of the present invention.

FIG. 8 is a plan view of a seal plate showing a rib shape in the gear pump.

FIG. 9 is an exploded perspective view of a gear pump according to Embodiment 3 of the present invention.

FIG. 10 is an exploded perspective view of a gear pump according to a fourth embodiment of the present invention.

FIG. 11 is an exploded perspective view of an example of a conventional gear pump.

FIG. 12 is a sectional plan view of a gear portion of the gear pump.

13 is a sectional view taken along the line KK in FIG.

FIG. 14 is an exploded perspective view of another conventional gear pump.

FIG. 15 is a side sectional view of the gear pump.

[Description of Signs] 1 gear case 1a suction port 1b discharge port 2 gear cover 2a cutout 3 drive gear 4 driven gear 5 drive shaft 6 driven shaft 7 O-ring 8 oil seal 9 mounting screw 10 gear chamber 10a discharge chamber 10b suction chamber 11 seal Plate 12 Seal plate 12a Rib 12b Rib 12c Rib 13 Rubber sheet 14 Gap 20 Motor

Claims (8)

[Claims] 1. A gear pump using water as a working fluid,
In the gear chamber, a seal plate, a drive gear and a driven gear made of a material having a small frictional resistance, a seal plate having a gear side surface having a small frictional resistance, and a rubber sheet are sequentially arranged,
A gear pump, wherein a seal plate having a rubber sheet overlapped on a back surface opposite to the gear is restrained by the rubber sheet in the gear chamber and pressed against a side surface of the gear. 2. A seal plate in which a rubber sheet is superimposed on a back surface opposite to the gear side, has a rib on the back surface for separating a discharge high pressure side and a suction low pressure side of a gear chamber, and a discharge side on a back surface of the seal plate. The gear pump according to claim 1, further comprising means for applying a high pressure. 3. A plurality of ribs, which are distributed while gradually preventing the pump discharge pressure guided to the back surface of the seal plate from leaking to the suction side, and the force for pressing the seal plate against the side surface of the gear is provided. The repulsion force due to the leak pressure that tries to separate the seal plate on the gear side is approximately matched to the line of action, and the moment of the seal plate is suppressed, and the resultant force is minimized and always acts in the direction of pressing the seal plate against the gear side. 3. The gear pump according to claim 2, wherein the gear pump is formed. 4. The rubber sheet has a rib on the surface on the seal plate side for separating the high pressure side of the gear chamber from the discharge high pressure side and the suction low pressure side.
2. The gear pump according to claim 1, further comprising means for applying a discharge-side high voltage to a back surface of the seal plate from a gap between the rubber sheet and the seal plate. 5. A plurality of ribs, which are distributed while stepwise preventing the pump discharge pressure guided to the back surface of the seal plate from leaking to the suction side, and the force for pressing the seal plate against the gear side surface is provided. The repulsion force due to the leak pressure that tries to separate the seal plate on the gear side is approximately matched to the line of action, and the moment of the seal plate is suppressed, and the resultant force is minimized and always acts in the direction of pressing the seal plate against the gear side. The gear pump according to claim 4, wherein the gear pump is formed so as to perform the following. 6. The gear pump according to claim 1, wherein the seal plate having a small frictional resistance is formed of any one of polyacetal resin, polyphenylene sulfide resin, and polyphenylene ether resin. 7. The gear pump according to claim 1, wherein the seal plate having a small frictional resistance is formed by coating a surface on the gear side with 4-hooker ethylene resin. 8. The gear pump according to claim 1, wherein the seal plate having a small frictional resistance is polished to a surface roughness of 0.8S to 6.3S.