JP2010144570A - Gear pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To finely control a workload in a gear pump. <P>SOLUTION: This gear pump includes: a gear group 1 composed of not less than four even-numbered gears 1a to 1d annularly arranged with adjacent gears engaged with each other; a first casing 2 surrounding the outside of the gear group 1 and increasing the pressure of fluid within the clearance areas R between the gears 1a to 1d and the first casing; a second casing 3 arranged in a center area surrounded by the gear group 1 and increasing the pressure of the fluid within clearance areas R between the gears 1a to 1d and the second casing; an inlet flow passage 4 supplying the fluid to the clearance areas R; and a delivery flow passage 5 delivering the fluid from the clearance areas R. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gear pump that pressurizes and discharges fluid in a gap region between a gear and a casing.

Conventionally, a triple gear pump including three gears has been known as a pump for boosting and discharging a fluid.
As shown in Patent Document 1, the triple gear pump includes a gear group including three meshed gears and a casing surrounding the gear group, and a gap between each gear and the casing. The fluid is pressurized and discharged in the region.
Such a triple gear pump has four gap areas, and pressurizes the fluid in each gap area.
JP 2005-42627 A

  By the way, in a pump, the work amount which a pump performs may be adjusted according to the use environment of a pump. For this reason, in the triple gear pump, for example, by using an unloading device or the like, the work volume performed by the pump is adjusted by limiting the gap area where the fluid is boosted among the four gap areas.

  However, since the triple gear pump has only four gap regions as described above, the amount of work performed by the pump cannot be finely controlled.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to propose a form of a gear pump capable of finely controlling the work amount.

  The present invention adopts the following configuration as means for solving the above-described problems.

  1st invention is a gear pump, Comprising: The gear group which consists of an even number of 4 or more gears which adjoin mutually and are cyclically arranged, and encloses the outer side of this gear group, and between the said gear and itself A first casing capable of boosting fluid in the gap region, a second casing disposed in a central region surrounded by the gear group and capable of boosting the fluid in the gap region between the gear and itself, and the gap A configuration is adopted in which an inlet channel for supplying the fluid to the region and a discharge channel for discharging the fluid from the gap region are employed.

  According to a second aspect of the present invention, in the first aspect of the present invention, a bypass channel capable of directly connecting the inlet channel and the discharge channel without passing through the gap region, and an opening / closing for adjusting the opening / closing of the bypass channel A configuration is provided that includes adjusting means.

  According to a third invention, in the first or second invention, a configuration is provided in which fluid supply adjusting means for adjusting supply of the fluid to the inlet channel is provided.

  According to a fourth invention, in any one of the first to third inventions, a configuration is provided in which moving means that allows the second casing to be inserted into and removed from the central region is employed.

  According to a fifth invention, in any one of the first to fourth inventions, a configuration is used in which fuel of a jet engine is used as the fluid.

According to the present invention, gap regions for pressurizing fluid are formed between the gears constituting the gear group and the first casing and between the gears and the second casing. That is, two gap regions are formed for one gear. For this reason, according to the present invention, at least eight gap regions are formed, and the number of each gap region where the pressure of the fluid is increased is increased as compared with the conventional case.
Therefore, according to the present invention, it becomes possible to finely control the work amount in the gear pump.

  Hereinafter, an embodiment of a gear pump according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

(First embodiment)
1 and 2 are cross-sectional views schematically showing a schematic configuration of the gear pump 100 of the present embodiment. FIG. 1 is a cross-sectional view in a plane perpendicular to the axial direction of the gear, and FIG. It is an AA sectional view taken on the line.
As shown in these drawings, the gear pump 100 of the present embodiment includes a gear group 1, a first casing 2, a second casing 3, an inlet flow path 4, a discharge flow path 5, and an unload device 6. And a fluid supply device 7 (fluid supply adjusting means) and a moving device 8 (moving means).

The gear group 1 is composed of four (even number) gears 1a to 1d that are adjacently meshed with each other and arranged in an annular shape.
In addition, in this embodiment, although each gear 1a-1d is a gear with the same diameter, the diameter of each gear 1a-1b does not necessarily need to be the same.

Each of the gears 1a to 1d is driven to rotate by rotating one or more of the shafts (not shown) of the gears 1a to 1d by a motor or the like.
In the gear pump 100 of this embodiment, as shown in FIG. 1, the gear 1a and the gear 1c are rotationally driven so as to rotate clockwise in FIG. 1, and the gear 1b and the gear 1d are rotated counterclockwise in FIG. Driven by rotation.

The first casing 2 forms the outer shape of the gear pump 100 of the present embodiment and is disposed so as to surround the outer side of the gear group 1.
The first casing 2 is capable of boosting fluid in the gap region R between the gears 1a to 1d constituting the gear group 1 and itself.
In the following description, the gap region R formed between the gear group 1 and the first casing 2 is referred to as an outer gap region RA, and further, the outer gap formed between the gear 1a and the first casing 2. The region RA is referred to as a first outer clearance region RA1, and the outer clearance region RA formed between the gear 1b and the first casing 2 is referred to as a second outer clearance region RA2 between the gear 1c and the first casing 2. The outer gap area RA formed in the above is called a third outer gap area RA3, and the outer gap area RA formed between the gear 1d and the first casing 2 is called a fourth outer gap area RA4.

The second casing 3 is arranged in a central region surrounded by the gear group 1 and can pressurize the fluid in a gap region R between the gears 1a to 1d constituting the gear group 1 and itself.
In the following description, the gap region R formed between the gear group 1 and the second casing 3 is referred to as an inner gap region RB, and further, the inner gap formed between the gear 1a and the second casing 3. The region RB is referred to as a first inner clearance region RB1, the inner clearance region RB formed between the gear 1b and the second casing 3 is referred to as a second inner clearance region RB2, and between the gear 1c and the second casing 3 is defined. The inner gap area RB formed in the above is called a third inner gap area RB3, and the inner gap area RB formed between the gear 1d and the second casing 3 is called a fourth inner gap area RB4.

The inlet channel 4 is a channel for supplying a fluid from the outside of the gear pump 100 to the gap region R, and as shown in FIG. 1, four are installed in the gear pump 100 of the present embodiment.
More specifically, the inlet flow path 4 (hereinafter referred to as the first flow path 4) that can supply the fluid to the first outer gap area RA1 and the fourth outer gap area RA4 by flowing the fluid toward the area where the gear 1a and the gear 1d mesh with each other. 1 inlet channel 4a) and an inlet channel capable of supplying fluid to the second outer gap region RA2 and the third outer gap region RA3 by flowing the fluid toward the region where the gear 1b and the gear 1c mesh with each other. 4 (hereinafter referred to as the second inlet channel 4b) and the fluid flows into the region where the gear 1a and the gear 1b are separated from each other, thereby causing the fluid to flow into the first inner clearance region RB1 and the second inner clearance region RB2. The third inner clearance region RB3 and the fourth inner clearance region RB3 are formed by allowing the fluid to flow toward a region where the feedable inlet channel 4 (hereinafter referred to as the third inlet channel 4c) and the gear 1c and the gear 1d are separated from each other. Side gap region RB4 fluid can be supplied inlet channel 4 (hereinafter, referred to as a fourth inlet channel 4d) and is installed.

The discharge flow paths 5 are flow paths for discharging fluid from the gap region R, and as shown in FIG. 1, four discharge pumps 5 are installed in the gear pump 100 of the present embodiment.
More specifically, a discharge flow path 5 (hereinafter referred to as a first discharge flow path 5a) for discharging fluid discharged from the first outer gap area RA1 and the second outer gap area RA2, and a third outer gap area RA3. And the discharge flow path 5 (hereinafter referred to as the second discharge flow path 5b) for discharging the fluid discharged from the fourth outer gap area RA4 and the first inner gap area RB1 and the fourth inner gap area RB4. A discharge flow path 5 for discharging fluid (hereinafter referred to as a third discharge flow path 5c), and a discharge flow path 5 for discharging fluid discharged from the second inner gap area RB2 and the third inner gap area RB3 (hereinafter referred to as the third discharge flow path 5c) 4th discharge flow path 5d) is installed.

The unload device 6 allows fluid to directly flow (unload) from the inlet channel 4 to the discharge channel 5, and allows fluid to flow directly from the inlet channel 4 to the discharge channel 5. The bypass flow path 6a and an open / close adjuster 6b (open / close adjusting means) for adjusting the open / close of the bypass flow path 6a are provided.
For convenience of explanation, in the gear pump 100 of the present embodiment, as shown in FIG. 1, only one unloading device 6 that connects the first inlet channel 4a and the first discharge channel 5a is installed. Has been. However, the unloading device 6 may be installed so as to connect any of the inlet channels 4 and any of the discharge channels 5, and more than one may be installed.

  The fluid supply device 7 adjusts the supply of fluid to the inlet channel 4. The fluid supply device 7 is connected to each of the first inlet channel 4a, the second inlet channel 4b, the third inlet channel 4c, and the fourth inlet channel 4d, and the first inlet channel 4a. The fluid supply to the second inlet channel 4b, the third inlet channel 4c, and the fourth inlet channel 4d can be independently adjusted.

The moving device 8 enables the second casing 3 to be inserted into and removed from a central region surrounded by the gears 1a to 1d.
When the second casing 3 is inserted into the central region in the moving device 8, each inner clearance region RB is independent by the second casing 3. On the other hand, when the 2nd casing 3 is extracted from the said center area | region in the moving apparatus 8, each inner clearance area | region RB is connected by the area | region formed when the 2nd casing 3 is extracted. .
In addition, the 2nd casing 3 should just be moved to such an extent that the area | region where each inner side clearance area | region RB is connected can be formed. For this reason, the movement apparatus 8 does not need to be able to move the 2nd casing 3 so that it can extract completely from the said center area | region, and should just be able to move the 2nd casing 3 slightly.

  In the gear pump 100 of the present embodiment configured as described above, the gears 1a to 1d are rotationally driven, and the bypass flow path 6a of the unload device 6 is closed. On the other hand, when the fluid is supplied, the fluid is pressurized in each gap region R and discharged, and is discharged to the outside through the discharge channel 5.

  More specifically, as shown in FIG. 1, the fluid supplied to the first inlet channel 4a is supplied to the first outer gap region RA1 and the fourth outer gap region RA4. Then, the fluid supplied to the first outer gap region RA1 is pressurized in the first outer gap region RA1 and discharged from the first discharge flow path 5a to the outside of the gear pump 100. On the other hand, the fluid supplied to the fourth outer gap region RA4 is pressurized in the fourth outer gap region RA4 and discharged from the second discharge passage 5b to the outside of the gear pump 100.

  Further, the fluid supplied to the second inlet channel 4b is supplied to the second outer gap region RA2 and the third outer gap region RA3. Then, the fluid supplied to the second outer gap region RA2 is pressurized in the second outer gap region RA2 and discharged from the first discharge flow path 5a to the outside of the gear pump 100. On the other hand, the fluid supplied to the third outer gap region RA3 is pressurized in the third outer gap region RA3 and discharged from the second discharge passage 5b to the outside of the gear pump 100.

  Further, the fluid supplied to the third inlet channel 4c is supplied to the first inner gap region RB1 and the second inner gap region RB2. Then, the fluid supplied to the first inner clearance region RB1 is pressurized in the first inner clearance region RB1 and discharged from the third discharge flow path 5c to the outside of the gear pump 100. On the other hand, the fluid supplied to the second inner clearance region RB2 is pressurized in the second inner clearance region RB2, and discharged from the fourth discharge flow path 5d to the outside of the gear pump 100.

  In addition, the fluid supplied to the fourth inlet channel 4c is supplied to the third inner clearance region RB3 and the fourth inner clearance region RB4. Then, the fluid supplied to the third inner clearance region RB3 is pressurized in the third inner clearance region RB3 and discharged from the fourth discharge flow path 5d to the outside of the gear pump 100. On the other hand, the fluid supplied to the fourth inner clearance region RB4 is pressurized in the fourth inner clearance region RB4 and discharged from the third discharge flow path 5c to the outside of the gear pump 100.

Subsequently, the fluid is supplied from the fluid supply device 7 to the first inlet channel 4a to the fourth inlet channel 4d, and the unloading device 6 directly supplies the fluid from the first inlet channel 4a to the first discharge channel 5a. The case of supplying will be described.
First, when the fluid is directly supplied from the first inlet channel 4a to the first discharge channel 5a, the bypass channel 6a is opened by the opening / closing controller 6b of the unload device 6.
At this time, when the connection destination of the first discharge flow path 5a is a structure such as a check valve in which the fluid cannot flow backward, the fluid flows from the first discharge flow path 5a to the low pressure side as shown by the arrows in FIG. The fluid flows into the first inlet channel 4a, and the pressures in the first inlet channel 4a and the first discharge channel 5a are equalized at a low pressure. As a result, the fluid pressure is not increased in the first outer gap region RA1, and the work of the gear pump 100 is reduced. More specifically, in the gear pump 100 of the present embodiment, there are eight gap regions R, and when the fluid is directly supplied from the first inlet channel 4a to the first discharge channel 5a by the unload device 6. Since no pressure is increased in one gap region R (first outer gap region RA1), the work amount in the gear pump 100 is 7/8.
When a check valve is installed on the liquid supply unit 7 side, as a result, the pressure in the first inlet channel 4a is increased and the pressure in the first inlet channel 4a and the first discharge channel 5a is increased. Equal to low pressure.

In addition, for example, an unload device that directly supplies fluid from the second inlet channel 4b to the second discharge channel 5b is installed, and the fluid is directly transferred from the second inlet channel 4b to the second discharge channel 5b by the unload device. Is not boosted in the third outer gap region RA3.
In addition, for example, an unload device that directly supplies fluid from the third inlet flow channel 4c to the third discharge flow channel 5c is installed, and the unload device directly connects the third inlet flow channel 4c to the third discharge flow channel 5c. When the fluid is supplied, the fluid pressure is not increased in the first inner clearance region RB1.
Further, for example, an unloading device that directly supplies a fluid from the fourth inlet channel 4d to the fourth discharge channel 5d is installed, and the unloading device directly connects the fourth inlet channel 4d to the fourth discharge channel 5d. When the fluid is supplied, the fluid pressure is not increased in the third inner gap region RB3.
As described above, in the gear pump 100 according to the present embodiment, any one of the inlet flow paths 4 and any one of the discharge flow paths 5 are connected by the unloading device to directly supply a fluid, so that one gap region R is provided. The pressurization of the fluid is not performed, and the work amount can be reduced by 1/8.
Even when the inlet flow path 4 and the discharge flow path 5 are connected by the unloading device 6 and the pressure of the fluid is not increased in the predetermined gap region R, the fluid flows into the predetermined gap region R. Have been supplied.

Next, with the bypass flow path 6a of the unload device 6 closed, the fluid from the fluid supply device 7 to only the second inlet flow path 4b among the first inlet flow path 4a to the fourth inlet flow path 4d. Explain that stopped supplying.
Of the first inlet channel 4a to the fourth inlet channel 4d, when the supply of fluid only to the second inlet channel 4b is stopped, the second outer gap region RA2 and the third outer gap region RA3 are supplied. The supply of fluid is stopped, the fluid pressure is not increased in the second outer gap region RA2 and the third outer gap region RA3, and the work of the gear pump 100 is reduced. More specifically, in the gear pump 100 of the present embodiment, there are eight gap regions R, and when the supply of fluid only to the second inlet channel 4b is stopped, two gap regions R (first 2) and the third outer gap region RA3) are not boosted, so the work amount in the gear pump 100 is 6/8.

When the supply of fluid to the first inlet channel 4a is stopped, the supply of fluid to the first outer gap region RA1 and the fourth outer gap region RA4 is stopped, and the first outer gap region RA1 and The fluid is not boosted in the fourth outer gap region RA4.
Further, when the supply of the fluid to the third inlet channel 4c is stopped, the supply of the fluid to the first inner clearance region RB1 and the second inner clearance region RB2 is stopped, and the first inner clearance region RB1 and The fluid is not boosted in the second inner clearance region RB2.
In addition, when the supply of fluid to the fourth inlet channel 4d is stopped, the supply of fluid to the third inner clearance region RB3 and the fourth inner clearance region RB4 is stopped, and the third inner clearance region RB3 and The fluid is not boosted in the fourth inner clearance region RB4.
As described above, in the gear pump 100 according to the present embodiment, by stopping the supply of fluid to one inlet channel 4, the pressure increase in the two gap regions R is not performed, and the work amount is reduced by 2/8. Can do.
In the gear pump 100, the fluid always leaks at each location, and there is a considerable amount of fluid at all locations in the gear pump 100. For this reason, even if it is a case where supply of the fluid to inlet channel 4 is stopped, seizure of gears 1a-1d is controlled.

Next, the case where the 2nd casing 3 is extracted from the center area | region enclosed with the gears 1a-1d with the moving apparatus 8 is demonstrated.
When the second casing 3 is extracted from the central region, the first inner clearance region RB1 to the fourth inner clearance region RB4 are connected in the region formed by extracting the second casing 3 from the central region, and the first inner side The fluid is not boosted in the gap region RB1 to the fourth inner gap region RB4. For this reason, when the 2nd casing 3 is extracted from the center area | region enclosed with the gears 1a-1d with the moving apparatus 8, the work of the gear pump 100 will be 4/8.

  In the gear pump 100 of the present embodiment, the work amount can be finely adjusted from 1/8 to 8/8 by combining the operations of the unload device 6, the fluid supply device 7, and the moving device 8 described above. It becomes possible.

According to the gear pump 100 of the present embodiment as described above, fluid is provided between the gears 1a to 1d and the first casing 2 constituting the gear group 1 and between the gears 1a to 1d and the second casing 3. A gap region R for boosting is formed. That is, two gap regions are formed for one gear. For this reason, according to the gear pump 100 of the present embodiment, the eight gap regions R are formed, and the number of the gap regions R that pressurize the fluid is increased as compared with the conventional case.
Therefore, according to the gear pump 100 of the present embodiment, the work amount can be more finely controlled in the gear pump.

FIG. 4 is a system block diagram showing a schematic configuration of the fuel system 20 including the gear pump 100 of the present embodiment.
The fuel system 20 is, for example, a FADEC (Full Authority Digital Electronic Control) system that supplies fuel to an aircraft jet engine, and includes the gear pump 100, the fuel control unit 21, and the electronic control device 22 of the present embodiment. Yes.
In the fuel system 20, the gear pump 100 of this embodiment functions as a fuel pump that boosts and discharges fuel (fluid) supplied from a fuel tank or the like. The gear pump 100 is directly connected to the rotating shaft of the jet engine, and each gear rotates in proportion to the rotational speed of the jet engine.
Based on a command from the electronic control unit 22, the fuel control unit 21 supplies the jet engine with an amount of fuel discharged from the gear pump 100 and returns the rest to the gear pump 100. .
The returned fuel causes heat generation as an internal loss of the fuel pump. The fuel temperature rise is determined by dividing the heat generated by the fuel pump by the fuel flow rate and the specific heat of the fuel. The upper limit of the fuel temperature is generally 155 ° C. This is due to the heat resistance of the packing and aluminum alloy used in the fuel system 20 and the coking resistance (gumification and alteration resistance) of the fuel at around 155 ° C. for fuel (JP-4, JP-5 (equivalent to Jeta) and JP -8 (equivalent to JETA1)).
And when fuel is used as the refrigerant of the fuel cooling oil cooler used in the fuel system, if the fuel temperature is high, the cooling capacity of the fuel oil cooler will be reduced, so it will be necessary to install an air cooling oil cooler separately, etc. Countermeasures are required.

  The electronic control unit 22 calculates the amount of fuel to be supplied to the jet engine based on the number of revolutions of the jet engine and the instruction of the pilot of the aircraft equipped with the jet engine, and the gear pump 100 and the fuel control unit 21 based on the calculation result. To control.

  When the jet engine is started, the speed of the jet engine is low (about 10% of the steady speed) and the speed of each gear of the gear pump 100 is low, but a large amount of fuel is required. Therefore, the fuel control unit 21 controls the gear pump 100 of the present embodiment, thereby increasing the work amount of the gear pump 100 and increasing the fuel flow rate. The work amount of the gear pump 100 is proportional to the product of the discharge pressure, the discharge flow rate, and the mechanical efficiency.

Further, at the time of takeoff of an aircraft equipped with a jet engine, the jet engine requires a large amount of fuel, and the rotational speed of the jet engine is high and the rotational speed of each gear of the gear pump 100 is high. Therefore, the fuel control unit 21 increases the work amount of the gear pump 100 by controlling the gear pump 100 of the present embodiment. However, since the fuel flow rate is large, the fuel temperature rise is lower than the heat generation amount, and the fuel temperature rise is a problem. Not.
On the other hand, when cruising an aircraft equipped with a jet engine, although the fuel consumption of the jet engine is reduced, the rotational speed of the jet engine is relatively high and the rotational speed of each gear of the gear pump 100 is higher than at the start. For this reason, the fuel control unit 21 can avoid an increase in the fuel temperature by reducing the work amount of the gear pump 100 by using the unloading device and the moving device of the gear pump 100 of the present embodiment.

  According to such a fuel system 20, the amount of fuel returned to the gear pump 100 by the fuel control unit 21 can be reduced by reducing the work amount of the gear pump 100. For this reason, it becomes possible to reduce the internal circulation amount of the fuel in the fuel system 20 and prevent the temperature of the fuel from rising. Further, the required amount of fuel can be supplied to the jet engine by increasing the work amount of the gear pump 100 as necessary.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the present embodiment, the description of the same parts as those in the first embodiment will be omitted or simplified.

FIG. 5 is a cross-sectional view schematically showing a schematic configuration of the gear pump 200 of the present embodiment, and is a cross-sectional view in a plane perpendicular to the axial direction of the gear.
As shown in this figure, the gear pump 200 of the present embodiment includes a gear group 10 including six (even number) gears 10a to 10f arranged adjacent to each other.

And the 1st casing 2 surrounds the outer side of the said gear group 10, and the 2nd casing 3 is arrange | positioned in the center area | region enclosed by gear 10a-10f.
In addition, an outer gap region RA that pressurizes the fluid is formed between the gears 10 a to 10 f and the first casing 2, and an inner gap region that boosts the fluid between the gears 10 a to 10 f and the second casing 3. RB is formed. That is, in the gear pump 200 of the present embodiment, a total of 12 gap regions R for boosting the fluid are formed.

  In addition, one inlet channel 4 and one discharge channel 5 are provided for the two gap regions R. That is, in the gear pump 200 of the present embodiment, a total of six inlet channels 4 and discharge channels 5 are installed.

  Although not shown in FIG. 1, the gear pump 200 of the present embodiment also applies fluid directly from one of the inlet channels 4 to any one of the discharge channels, similarly to the gear pump 100 of the first embodiment. An unload device 6 that can flow in, a fluid supply device 7 that can adjust the supply of fluid independently to each of the inlet channels 4, and a moving device 8 that can insert and remove the second casing 3 are provided.

According to the gear pump 200 of the present embodiment as described above, a fluid is provided between the gears 10a to 10f constituting the gear group 10 and the first casing 2 and between the gears 10a to 10f and the second casing 3. A gap region R for boosting is formed. That is, two gap regions are formed for one gear. For this reason, according to the gear pump 100 of the present embodiment, twelve gap regions R are formed, and the number of each gap region R that pressurizes the fluid is increased as compared with the conventional case.
Therefore, according to the gear pump 200 of the present embodiment, the work amount can be more finely controlled in the gear pump.

  As described above, the preferred embodiment of the gear pump according to the present invention has been described with reference to the accompanying drawings, but it is needless to say that the present invention is not limited to the above-described embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the above-described embodiment, the configuration including four or six gears has been described.
However, the present invention is not limited to this, and the number of gears may be larger as long as it is an even number.

It is sectional drawing which shows typically schematic structure of the gear pump in 1st Embodiment of this invention, and is sectional drawing in the surface orthogonal to the axial direction of a gear. It is the sectional view on the AA line of FIG. It is a schematic diagram which shows the flow of the fluid at the time of unloading in the gear pump in 1st Embodiment of this invention. It is a system block diagram of a fuel system provided with the gear pump in a 1st embodiment of the present invention. It is sectional drawing which shows typically schematic structure of the gear pump in 2nd Embodiment of this invention, and is sectional drawing in the surface at right angles to the axial direction of a gear.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100,200 ... Gear pump, 1,10 ... Gear group, 1a-1d, 10a-10f ... Gear, 2 ... 1st casing, 3 ... 2nd casing, 4 ... Inlet flow path, 5 ... Discharge flow path, 6 ... Unload device, 6a ... Bypass flow path, 6b ... Opening / closing adjusting part (opening / closing adjusting means), 7 ... Fluid supply part (fluid supply adjusting means), 8 ... Moving device (moving) Means), R... Clearance area, RA... Outer clearance area, RB... Inner clearance area, RA1... First outer clearance area, RA2... Second outer clearance area, RA3. RA4: Fourth outer clearance region, RB1: First inner clearance region, RB2: Second inner clearance region, RB3: Third inner clearance region, RB4: Fourth inner clearance region

Claims (5)

A gear group composed of an even number of four or more gears that are adjacently meshed and arranged in a ring shape;
A first casing surrounding the outside of the gear group and capable of boosting fluid in a gap region between the gear and itself;
A second casing disposed in a central region surrounded by the gear group and capable of boosting the fluid in a gap region between the gear and itself;
An inlet channel for supplying the fluid to the gap region;
A gear pump comprising: a discharge flow path for discharging the fluid from the gap region. A bypass channel capable of directly connecting the inlet channel and the discharge channel without the gap region;
The gear pump according to claim 1, further comprising: an opening / closing adjustment means for adjusting opening / closing of the bypass flow path.   The gear pump according to claim 1, further comprising a fluid supply adjusting unit that adjusts the supply of the fluid to the inlet channel.   The gear pump according to any one of claims 1 to 3, further comprising moving means that allows the second casing to be inserted into and removed from the central region. The gear pump according to any one of claims 1 to 4, wherein fuel of a jet engine is used as the fluid.

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