JP2000265975A - Gear pump, fuel supplying device using it, and gear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve miniaturization, reduction of cost and improvement of efficiency, in a gear pump having externally provided teeth to be meshed with each other to form a pump part and a driven part, a fuel supplying device, and a gear motor. SOLUTION: In a pump in which a pump part for sucking fluid from one side of meshing parts of gears 31, 32 and 32' so arranged that their teeth provided on the peripheries may be meshed and rotated in a case 21, for increasing the pressures and for discharging fluid, two pump parts are formed by meshing two driven gears 32, 32' with the common drive gear 31, and two pump parts are connected in series into a two-stage pump part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump, a fuel supply device using the same, and a gear motor, and more particularly, to a gear arranged such that teeth provided on the outer periphery in a case mesh with each other and rotate. And a fuel pump and a gear motor using the same.

[0002]

2. Description of the Related Art As a first prior art of a gear pump, there is provided a case forming a closed space, and a gear arranged in such a manner that teeth provided on an outer periphery of the case mesh with each other and rotate. There is a pump configured to suck a fluid from one side of a meshing portion of the gear and pressurize the fluid to discharge the fluid to the other side.

As a second prior art of a gear pump, the above-mentioned first prior art gear is rotatably slidably sandwiched between side plates in order to reduce the internal leakage of fluid. It is known as described in -317260. Note that Japanese Patent Application Laid-Open No. Hei 6-317260 discloses a gear motor.

Further, as a third prior art of the gear pump, there is provided a seal block for sealing the tooth tip of the above second prior art in order to reduce the internal leakage of fluid,
For example, it is publicly known as described in JP-A-10-252589. Note that this Japanese Patent Application Laid-Open No. 10-252589
The publication discloses a fuel tank comprising a fuel tank, a feed pump for increasing the pressure of the fuel in the fuel tank, and a fuel supply pump for further increasing the pressure of the fuel increased by the feed pump and supplying high-pressure fuel to a fuel injection valve of the engine. A supply device is shown.

As a fourth prior art gear pump, a pump unit having gears arranged so that teeth provided on the outer periphery thereof mesh with each other and rotate is connected in two stages in the axial direction in series. There is.

[0006]

However, in the first to third prior art gear pumps described above, the pump section is one-piece.
Since the pressure difference between the discharge side pressure and the suction side pressure is all applied to the one-stage pump section, the internal leakage of the fluid proportional to this pressure difference is large. In particular, when used in a fuel supply system for a direct injection gasoline engine, the viscosity of gasoline is extremely low, ie, less than half that of water and about 100 times less than that of general hydraulic oil. In order to be able to inject gasoline even in the compression process, it must be injected at a high pressure of, for example, more than 10 MPa. In addition, it is used in a wide rotation range from low-speed rotation to high-speed rotation. Because of the necessity of a gear pump, there is a need for a small-sized gear pump that has a small internal leakage of the fluid in a wide rotation range from low-speed rotation to high-speed rotation, can obtain a high discharge pressure, and is small.

In the fourth prior art gear pump, a pump unit having gears arranged on the outer periphery so as to rotate by meshing with each other is connected in two stages in the axial direction in series. Therefore, it is necessary to provide a pair of gears for the pump section of each stage independently for each stage, which results in a complicated configuration with many parts, and a long axial length, which results in an expensive and large Had become. The gear pump in which the pump units are connected in two stages in the axial direction does not have a configuration in which the pump unit is rotatably slidably sandwiched between side plates, or does not include a seal block that seals a tooth tip.

An object of the present invention is to provide a small, inexpensive and efficient gear pump, a fuel supply device and a gear motor.

[0009]

A first feature of the present invention to achieve the above object is that a case forming a closed space and teeth provided on an outer periphery in the case mesh with each other to rotate. Gear pump, comprising a pump unit configured to suction a fluid from one side of the meshing unit and pressurize the fluid and discharge the fluid to the other side. A plurality of gears are meshed with a plurality of gears to form a plurality of pumps, and the plurality of pumps are connected in series to form a plurality of stages of pumps.

A second feature of the present invention is that a case having a suction port and a discharge port and forming a closed space, and teeth provided on the outer periphery in the closed space of the case mesh with each other to rotate. And a gear disposed in the gear section, wherein the gear constitutes a pump section for sucking and raising fluid from one side of the meshing section and discharging the fluid to the other side, and the pump section has a suction side connected to the suction port. In a gear pump in which a discharge side is connected to the discharge port, the pump unit forms a plurality of pump units by meshing a plurality of gears with a common gear, and closes the plurality of pump units to the case. The present invention is characterized in that a plurality of pump sections are connected in series via a space.

[0011] A third feature of the present invention is that a case forming a closed space, a gear disposed so that teeth provided on an outer periphery in the case mesh with each other and rotate, and that the gear rotates. A side plate that is slidably sandwiched, wherein the gear is a gear pump that constitutes a pump unit that suctions fluid from one side of the meshing unit and pressurizes and discharges the fluid to the other side. A plurality of gears are meshed with a common gear to form a plurality of pumps, the plurality of pumps are connected in series to form a plurality of stages of pumps, and the side plates are formed into a plurality of pumps. It has been provided over the straddle.

A fourth feature of the present invention is that a case having a suction port and a discharge port and forming a closed space, and teeth provided on an outer periphery in the closed space of the case mesh with each other to rotate. And a seal block that seals the tooth tip of the gear, wherein the gear constitutes a pump unit that sucks up fluid from one side of the meshing unit and discharges the fluid to the other side, In the gear pump, wherein a pump side is connected to the suction port on a suction side and a discharge side is communicated with the discharge port, the pump section meshes two gears with a common gear to form two pump parts. The two pump units are connected in series to form a two-stage pump unit. The seal block is provided on the first stage suction side of the pump unit to form a suction passage. Second stage discharge It said seal block is provided to form a discharge passage, thereby connecting the suction passage to the suction port of the casing, in that connected to the discharge passage to a discharge port of the case.

A fifth feature of the present invention is that a case having a suction port and a discharge port and forming a closed space, and teeth provided on an outer periphery in the closed space of the case mesh with each other to rotate. , A side plate that rotatably slidably sandwiches the gear, and a seal block that seals the tooth tip of the gear, wherein the gear sucks fluid from one side of its meshing portion. A pump unit configured to increase the pressure and discharge the pressure to the other side, wherein the pump unit is a gear pump in which a suction side is connected to the suction port, and a discharge side is communicated with the discharge port. And two gears are meshed with each other to form two pumps, and the two pumps are connected in series via the closed space of the case to form a two-stage pump. At the suction side of the stage, The suction block is formed by providing a suction block, a suction passage is formed by providing the seal block on the second-stage discharge side of the pump section, and the suction passage is connected to a suction port of the case. The discharge passage is connected to a discharge port of the case, and the side plate is provided so as to straddle a gear forming two pump units.

A sixth feature of the present invention is that a case having a suction port and a discharge port and forming a closed space, and teeth provided on an outer periphery in the closed space of the case mesh with each other to rotate. , A pair of side plates sandwiching the gear so as to be rotatable and slidable, and a seal block for sealing the tooth tip of the gear, wherein the shaft on both sides is supported by the case. And a driven gear having a driven gear whose both shafts are pivotally supported by the side plate, and constituting a pump portion that sucks fluid from one side of the meshing portion and pressurizes and discharges the fluid to the other side. The pump unit is a gear pump in which a suction side is connected to the suction port and a discharge side is communicated with the discharge port. In the gear pump, the pump unit meshes the driven gear with two driven gears to form two pumps. Part, and the two ports Pump section is connected in series via the closed space of the case to form a two-stage pump section, and the seal block is provided on the suction side of a first-stage pump section constituted by one of the driving gear and the driven gear. To form a suction passage, and the seal block is provided independently on the discharge side of a second stage pump unit constituted by the drive gear and the driven gear to form a discharge passage. Connect the discharge passage to the suction port of the case, connect the discharge passage to the discharge port of the case, introduce high pressure in the discharge passage to the opposite gear side of the seal block that forms the discharge passage, and move this seal block to the gear side. The drive gear and the two driven gears that form the two pump sections with the side plates forming the two pump sections, by providing a pressing means for pressing the two seal blocks to the same thickness as the gears. A first sealing member provided so as to be sandwiched between two seal blocks and configured to partition and seal a low-pressure portion communicating with the suction passage and a pressure portion in the case on the opposite gear side of the side plate; When,
A high pressure portion communicating with the discharge passage and a second seal member for partitioning and sealing the pressure portion in the case, and the first seal member surrounds a shaft of the drive gear to form a low pressure region; The three gears are arranged so that the positions of their axes form a substantially triangular shape.

A seventh feature of the present invention is that a fuel tank, a feed pump for increasing the pressure of the fuel in the fuel tank, and further increasing the pressure of the fuel increased by the feed pump to supply high-pressure fuel to a fuel injection valve of the engine. A fuel supply pump, wherein the gear pump includes a case forming a closed space, and a gear arranged so that teeth provided on an outer periphery in the case mesh with each other and rotate, and the gear is In a fuel supply device comprising a pump unit that sucks in fluid from one side of the meshing unit and pressurizes and discharges the fluid to the other side, the pump unit of the fuel supply pump meshes a plurality of gears with a common gear. A plurality of pump sections are formed in total, and the plurality of pump sections are connected in series to form a multi-stage pump section.

According to an eighth feature of the present invention, there is provided a case forming a closed space, and a gear arranged such that teeth provided on an outer periphery in the case mesh with each other and rotate.
The gear is a gear motor that constitutes a motor drive unit that is rotated by being supplied with fluid from one side of the meshing unit and discharging to the other side, wherein the motor drive unit has a plurality of common gears. A plurality of motor driving units are formed by meshing gears, and the plurality of motor driving units are connected in series to form a plurality of motor driving units.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gear pump according to the present invention will be described below with reference to the drawings. In the drawings of the respective embodiments, the same reference numerals indicate the same or corresponding components, and duplicate description will be omitted.

FIG. 1 is a longitudinal sectional view showing a first embodiment of a gear pump according to the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG.
FIG. 4 is a sectional view taken along line BB of FIG. 1, and FIG. 4 is a sectional view taken along line CC of FIG.

1 to 4, the case 21 is composed of a casing 37 and a cover 41. The casing 37 is formed in a cylindrical shape with an opening at the bottom, the outer periphery is cylindrical, and the inner periphery is formed by two flat portions and two arc portions facing each other. A bearing recess 37b is provided at the center of the bottom surface. The cover 41 is formed in a flat plate shape, the outer periphery is a square shape corresponding to the outer periphery of the flange portion 37a of the casing 37, and a through hole 41a is formed in the center. A side surface of the flange portion 37a of the casing 37 and a side surface of the cover 41 have a resilient sealing member, for example, O
The case 21 is configured to be abutted via a ring 42 and fixed with a fastener, for example, a bolt or the like. In the closed space 22 of the case 21, gears 31, 32, 32 ', side plates 34,
34 ', seal blocks 33, 33' and the like are accommodated. At the bottom of the casing 37, a suction port 35a and a discharge port 36a communicating with the suction passage 35 and the discharge passage 36 are provided. The drive gear 31 includes a cover 41
Bearing 39 and casing 37 provided in the central hole 41a of
A drive shaft 31a projecting to both sides is supported by a bearing 39 'provided in the concave portion 37b. The first and second driven gears 32, 32 'have substantially the same tooth width, outer shape, and the like as the drive gear 31, and mesh with the drive gear 31 from both sides to rotate, thereby forming a pump section that performs a pumping action. Side plate 34,
Reference numeral 34 'slides over the side surfaces of the gears 31, 32, 32' to seal the side surfaces of the gears 31, 32, 32 ', and the gear shafts 32a, 3 of the driven gears 32, 32'.
2a '. This seal side plate 34,
34a ', the driving gear 31, the driven gears 32 and 32'.
Shafts 31a, 32a and 32a 'are supported in parallel and at a predetermined interval. Each gear 31, 32, 32 '
3 and 4 are housed in the space 22 of the case 21 apart from the inner peripheral surface of the casing 37, and between the bottom surface of the casing 37 and the side surface of the cover 41,
34 '. Specifically, the internal depth of the casing 37, that is, the depth of the space 22 of the case 21 is determined by the side plates 34, 34 'and the gears 31, 32, or 32'.
Is slightly deeper than the overlapped thickness, the side plates 34, 34 'do not directly contact the case 21, but the sealing members 38, 38' and 49, 49 'inserted between them.
And supported by the elastic force of

As shown in FIGS. 3 and 4, the side plates 34 and 34 'are formed with a suction passage 35 serving as a suction passage and a discharge passage 36 serving as a discharge passage together with the seal blocks 33 and 33'. The outer edge R in the vicinity of the port is formed substantially equal to the diameter of the addendum circle of each gear 31, 32, 32 '. The seal block 33 is provided so as to form a suction passage 35 for the gears 31 and 32 constituting the first-stage pump, and the tooth top surfaces of the gears 31 and 32 so as to seal the tooth tip in the vicinity of the suction passage 35. And side plate 3
4, 34 '. Seal block 33 '
Are provided so as to form the discharge passages 36 of the gears 31 and 32 ′ constituting the second stage pump, and the gears 31 and 32 ′ are provided so as to seal the tooth tips near the discharge passage 36.
32 'is in contact with the tip surface and the side plates 34, 34'. That is, the sealing surfaces of the seal blocks 33, 33 'are formed to be substantially equal to the diameters of the addendum circles of the gears 31, 32, 32'.
It is held at both ends while being joined to the outer edge R of the 4 '.

The suction passage 35 is formed in the side plates 34 and 34 ', the seal block 33 and the casing 37. The fluid sucked from the suction passage 35 by the first-stage pump action of the gears 31 and 32 is increased in pressure from the pressure P0 to the pressure P1 and is discharged into the space 22 of the case 21. The discharge passage 36 is formed by the side plates 34 and 34 ', the seal block 33', and the casing 37.
The fluid filled in the case by the second-stage pump action of the gears 31, 32 'is increased in pressure from the pressure P1 to the pressure P2, and is discharged from the discharge passage 36 to the outside. Here, the pressure P1 in the casing 37 becomes a substantially intermediate pressure between the two, and if the tooth gap and the side gap of the pumps at each stage are the same, P1
1 = (P2−P0) / 2. Therefore, in order to generate a predetermined pressure, the pressure difference per pump is reduced as compared with a single-stage pump. In this embodiment, the pressure difference is reduced by half, so that the internal leakage from the gap is reduced by half, and the volumetric efficiency is reduced. It can be greatly improved.

The seal block 33 of the first stage pump
Is automatically pressed toward the gears 31 and 32 and the side plates 34 and 34 'by the pressure difference between the suction pressure P0 and the casing internal pressure P1 to perform tooth tip sealing. On the other hand, since the inner discharge pressure P2 is higher than the outer pressure P1, the seal block 33 'of the second stage pump is
4, 34 '. For this reason, the seal block 33 'is provided with a hole 33a therein as shown in FIGS. 2 to 4, and guides the discharge pressure P2 into the concave portion 33'b on the opposite side of the gear tooth tip of the seal block 33'. , 34 'are generated so as to oppose the separating force caused by the pressure on the tip side of the gear. The fluid guided into the concave portion 33'b is sealed by the sealing member 48, and the pressure P2
The pressure receiving area is adjusted to generate a sufficient pressing force to overcome the separating force. As a result, both the first-stage and second-stage pumps can realize a stable tooth tip seal, and a highly efficient two-stage gear pump can be configured by suppressing tip leakage.

In this embodiment, since the seal block 33 'is pressed in the direction of the gears 31 and 32' by its own discharge pressure P2, the structure can be simple and inexpensive. As a means, an elastic member such as a spring may be used, or fluid pressure and spring force may be combined.

Next, referring to FIG.
Reference numerals 8 ', 49, and 49' are fitted into grooves formed in the end surfaces of the side plate 34 and the seal block 33, and seal the joint surfaces of the suction passage 35 and the discharge passage 36, respectively. The sealing members 38 and 38 'are provided with a pressure P in the casing.
This is for preventing the fluid in the casing from communicating with the suction passage through this joint surface due to the pressure difference between the pressure P1 and the pressure P0 of the suction passage portion. Seal member 49
Is to prevent the discharged fluid from communicating with the inside of the casing through this joint surface due to the pressure difference between the discharge pressure P2 and the pressure P1 in the casing. The seal members 38 and 49 determine the pressure distribution on the side surfaces of the side plates 34 and 34 ′ opposite to the gear, balance the axial thrust with the pressure on the side surfaces of the gears of the side plates 34 and 34 ′, and set the gears 31, 32 and 3.
It also plays a role in preventing thrust thrust from being generated for 2 '. Thereby, the side plate 3 on the gear side surface
The gear side seal can be satisfactorily performed while preventing an increase in drive torque and seizure due to excessive pressing of the 4, 34 '.

The seal members 38 and 38 'are provided so as to surround both the suction passage 35 and the shaft 31a of the drive gear 31, so that the pressure around the shaft 31a of the drive gear 31 is low. The reason is that the rotary shaft seal 43 that seals the fluid inside the shaft 31a that penetrates to the outside of the pump can be used with a low pressure resistance. In other words, an oil seal that is highly reliable as a rotating shaft seal maintains stable sealing performance against shaft wear and inclination, and can be highly reliable when used in a fuel supply pump of a direct injection gasoline engine. Since there is a problem that the pressure resistance is low, high reliability can be obtained by using such a low pressure resistance.

Next, a second embodiment of the gear pump according to the present invention will be described with reference to FIGS. FIG. 5 is a view corresponding to FIG. 2 showing a second embodiment of the gear pump of the present invention, and FIG.
7 is a sectional view taken along line EE of FIG. In the present embodiment, the seal blocks 33, 33 'have substantially the same thickness as the tooth widths of the respective gears 31, 32, 32' and the side plates 34, 34 'are made larger than those of the first embodiment described above. Seal blocks 33, 33 'in addition to the gears 31, 32, 32'
Are also sandwiched between the side plates 34a and 34a '.

In the first embodiment, the seal block 3
According to the second embodiment, the seal blocks 33, 33 'are supported by the both side plates 34, 34' at both ends, and the partial cylindrical surfaces of the concave and convex portions are in contact with each other.
Since the sealing surface between the 33 'and the side plates 34, 34' is flat, the processing is significantly simplified, and high accuracy is easily obtained, and a gap is hardly formed. Moreover, the side plates 34, 34 '
Since the sealing surfaces in contact with the seal blocks 33, 33 'are the same as the sliding surfaces of the gears 31, 32, 32', machining of these surfaces can be performed simultaneously. Therefore, the side plate 3
In order to form a sealing surface between the seal blocks 33 and 33 'and the seal blocks 33 and 33', only new processing surfaces are required at both end surfaces of the seal blocks 33 and 33a ', thereby greatly reducing the number of processing steps. In addition, in the second embodiment, the partial cylindrical surface forming the tooth tip sealing surface of the seal blocks 33 and 33 'is shaved later by the tooth tip, so that it is similar to the seal blocks 33 and 33' of the first embodiment. There is an advantage that high-precision processing for preventing a gap is not required.

When the operation is started, the seal blocks 33, 33 'are driven by the discharge pressure P2 to rotate the gears 31, 32, 3.
2 'and pressed against the teeth of the gears 31, 32, 32' to form a good seal surface without gaps and move toward the gears. Since the movement amount is regulated by, there is no unnecessary cutting.

In the seal block type gear pump having such a configuration, the internal leakage can be reduced to almost half as in the first embodiment by increasing the pressure in two stages. Together with this, the volume efficiency can be further improved.

Next, a third embodiment of the gear pump according to the present invention will be described with reference to FIG. FIG. 8 is a view corresponding to FIG. 4 of a third embodiment of the multistage gear pump according to the present invention. In the first and second embodiments, the rotation shafts of the three gears 31, 32, 32 'are arranged in a straight line.
Are arranged so as to form a substantially triangular shape as shown in FIG. By arranging in this manner, the outer diameters of the three gears 31, 32, 32 'as a whole are reduced, so that the outer diameter of the pump can be reduced, and the mountability to a vehicle engine or the like is improved. Can be. Casing 37
Has a cylindrical inner peripheral surface 37c that substantially matches the overall outer shape of the three gears 31, 32, 32 '. Due to the provision of the seal blocks 33, 33 ', the cylindrical inner peripheral surface 37c has a center position slightly eccentric from the centers of the three gears 31, 32, 32', and the seal on the second pump side. The block 33 'has a flat portion 37d that abuts.

Next, the axial load of each gear in the above embodiment will be described with reference to FIGS. FIG. 9 is an explanatory view of the axial load in the first and second embodiments in which the gears are arranged in a straight line, and FIG. 10 is an explanatory view of the axial load in the third embodiment in which the gears are bent and arranged. In the first stage pump,
The area from the gear meshing portion near the suction passage 35 to the tooth seal portion by the seal block 33 is the suction pressure P0.
In all other portions, the casing pressure P1 is higher than P0, and a radial load F1 acts on the gears 31, 32 in the direction of the seal block 33. On the other hand, in the second stage pump, the area from the gear meshing portion near the discharge passage 36 to the tooth seal portion formed by the seal block 33 'is the discharge pressure P2, and all other portions are the casing internal pressure P1 lower than P2. And radial loads F on the gears 31 and 32 'in the direction opposite to the seal block 33'.
2 works. Accordingly, the resultant force Ft of these two radial loads F1 and F2 acts as the axial load of the drive gear 31, and in the example of FIG. 9, the angle of the radial loads F1 and F2 becomes 90 degrees or more, and the axial load F1 on the driven gear side. Can be smaller than In the example of FIG.
Is larger than the shaft load F1 on the driven gear side, but is smaller than the shaft load of the single-stage pump since the pressure difference per pump in the two-stage pump is half that of the single-stage pump. be able to. Although not shown, to further reduce the shaft load as compared with FIG. 9, each gear shaft may be arranged by bending in the opposite direction to that of FIG. In this case, if the gear has a large number of teeth, the seal block is relatively small, so that the seal block can be arranged.

Next, an embodiment of an engine fuel supply apparatus using a gear pump according to the present invention will be described with reference to FIGS.

FIG. 11 is a block diagram showing a first embodiment of the engine fuel supply device of the present invention. In FIG. 11, an engine 100 is provided with fuel injection valves 101a, 101b, 101c, and 101d for injecting fuel into a combustion chamber. Fuel, for example, gasoline, is first pressurized from a fuel tank 102 to a pressure of about 0.2 to 0.5 MPa by a feed pump 104 driven by a motor 103, and then further pressurized by a high-pressure fuel supply pump 3 to control the pressure. The fuel is adjusted to a predetermined fuel pressure of about 3 to 12 MPa by the valve 106 and supplied to the fuel injection valves 101 a to 101 d. The high-pressure fuel supply pump 3 is the gear pump shown in any of FIGS. 1 to 8, and is driven via the coupling 108 by the rotational force of the camshaft 107 of the engine 100. A feedback signal 110 from a pressure sensor 109 for detecting an output pressure of the pressure control valve 106 is compared with a target value 111, and a control command 113 is given to a pressure control valve driving circuit 114 with reference to information 112 from other sensors, Based on this, the fuel pressure of the pressure control valve 106 is controlled.

In the fuel supply system for an engine according to the first embodiment, since the gear pump of the present invention described above is used as the high-pressure fuel supply pump 3, the leakage is small and a high volumetric efficiency can be obtained from a low rotational speed range. In addition, it is possible to supply fuel at a sufficiently high pressure even at a low rotational speed such as when the engine is started or idling, and the engine 100 can be started reliably. As a result, a stable idling operation can be performed, so that an effect such as a smoother start can be obtained, and the driving performance of the vehicle equipped with the engine 100 is improved. In addition, since it is not necessary to select a pump having a large discharge rate in order to compensate for a decrease in volumetric efficiency in the low rotation range, the high-pressure fuel supply pump 3 and the feed pump 104 need to be small, and the high pressure fuel supply pump 3 and the feed pump 104 need to be small. Excessive fuel is not discharged in the rotation range, energy loss increases, fuel efficiency improves,
The relief flow rate from the pressure control valve 106 can be minimized to prevent cavitation and heat generation.
Numerous effects can be obtained, for example, the life of No. 6 is prolonged. Further, since the pressure in the suction passage of the high-pressure fuel supply pump 3 is kept higher than the saturated vapor pressure of the fuel by the discharge pressure of the feed pump 104, cavitation and erosion due to the cavitation are prevented, and high performance and reliability are long. You can keep it for a period. The high-pressure fuel supply pump 3
Is easy to manufacture and low in cost, so that the cost of the combustion supply device can be reduced. In addition, the small size and light weight make it easy to arrange devices in the engine room.

FIG. 12 is a block diagram showing a second embodiment of the fuel supply system for an engine according to the present invention. In FIG.
The high-pressure fuel supply pump 3 is configured to be driven by a motor 120 similarly to the feed pump 104. Further, the feedback signal 110 from the pressure sensor 109 is set to the target value 1
11 and giving a control command 121 to the motor drive circuit 122 with reference to information 112 from other sensors,
The fuel pressure is controlled by adjusting the rotation speed of the motor 120 based on this.

With such a configuration, in order to maintain a desired fuel pressure, only a required minimum flow rate can be discharged regardless of the operation of the engine 100. Therefore, the pressure control valve 106 in the first embodiment is unnecessary. Thus, it is possible to eliminate malfunctions such as operation failure due to foreign matter entry and performance degradation due to cavitation erosion. In addition, the number of revolutions of the high-pressure fuel supply pump 3 can be selected independently of the number of revolutions of the engine 100.
0, and from the development of pump 3 to production,
Pump 3 that can reduce costs up to maintenance and is effective in mass production
The effect of reducing the production cost is further increased.

Since the gear pump of the present invention can supply a fluid under high pressure and high efficiency under pressure as described above, one half of the water can be supplied.
It can be used for gasoline having only the following viscosities, and can be used for other fluids such as water, food, and medicine. Of course, if the gear pump of the present invention is used as a hydraulic source of a hydraulic device, it is possible to discharge at a higher pressure since leakage is small and high volumetric efficiency is obtained, and the working pressure of the gear pump exceeds 30 MPa. It is possible to increase the pressure. Thereby, the applicable range of the inexpensive gear pump can be expanded.

Although the embodiment of the gear pump has been described above, in the above-described configuration of the gear pump of the present invention, the high-pressure supply port supplied from the fluid pressure source to the discharge passage is connected to the low-pressure supply port reaching the reservoir to the suction passage. When the fluid flows by connecting the return ports respectively, the gear rotates in a direction opposite to the gear pump, and acts as a gear motor that converts fluid energy into mechanical rotation energy. If this gear motor is used, high efficiency can be obtained over a wide range from a small flow rate to a large flow rate, so that the effects of starting and stopping the motor can be improved, and the size and cost can be reduced.

In the present invention, a plurality of gears mesh with a common gear in the case to form a plurality of pump portions,
Since the plurality of pump sections are connected in series to form a multi-stage pump section, a high discharge pressure can be obtained with a small number of gears and a simple configuration, and a pressure difference per pump section at each stage can be reduced. Volumetric efficiency can be improved because the internal leakage of the fluid can be reduced. Thus, a compact, inexpensive and efficient gear pump can be obtained.

Since a plurality of pump sections are connected in series via a closed space of the case to form a plurality of pump sections,
A smaller and simpler configuration can be achieved.

Further, since the side plate is provided so as to straddle the gears forming the plurality of pump portions, the structure of the gear pump having the side plate can be simplified.

Further, a seal block is provided on the first stage suction side of the pump section to form a suction port.
A seal block is provided on the discharge side of the stage to form a discharge port, the suction port is connected to the suction port of the case, and the discharge port is connected to the discharge port of the case, so the suction side and discharge side of the pump are Sealing can be performed with a seal block, and internal leakage can be further reduced.

It should be noted that the present invention can be embodied in various other forms without departing from the spirit or main features thereof. As such, the preferred embodiments described in the present invention are illustrative and not restrictive. The scope of the invention is indicated by the claims,
All modifications falling within the meaning of the claims are to be included in the present invention.

[0044]

According to the present invention, a compact, inexpensive and efficient gear pump, fuel supply device and gear motor can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along the line BB of FIG. 1;

FIG. 4 is a cross-sectional view taken along the line CC of FIG. 1;

FIG. 5 is a longitudinal sectional view showing a second embodiment of the gear pump according to the present invention.

FIG. 6 is a sectional view taken along line DD of FIG. 5;

FIG. 7 is a sectional view taken along the line EE of FIG. 5;

FIG. 8 is a cross-sectional view showing a third embodiment of the gear pump according to the present invention.

FIG. 9 is an explanatory diagram showing bearing load vectors of the first and second embodiments of the gear pump of the present invention.

FIG. 10 is an explanatory diagram showing bearing load vectors of the gear pump according to the third embodiment of the present invention.

FIG. 11 is a configuration diagram showing a first embodiment of an engine fuel supply device of the present invention.

FIG. 12 is a configuration diagram showing a second embodiment of the engine fuel supply device of the present invention.

[Explanation of symbols]

3 gear pump (fuel supply pump), 21 case, 3
DESCRIPTION OF SYMBOLS 1 ... Drive gear, 32, 32 '... Follower gear, 33 ... Seal block, 34 ... Side plate, 35 ... Suction passage, 35a ... Suction port, 36 ... Discharge passage, 36a ... Discharge port, 37
... casing, 38 ... sealing member, 39 ... bearing, 41 ...
Front case, 42 O-ring, 43 rotating shaft seal, 44 retaining ring, 46 pin, 47 pin, 48 sealing member, 49 sealing member, 100 engine, 10
2: fuel tank, 104: feed pump, 101a-
101d: fuel injection valve.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F04C 2/18 321 F04C 2/18 321C (72) Inventor Yuzo Kadomukai 502, Kandatecho, Tsuchiura-shi, Ibaraki Stock (72) Inventor Hiroyuki Sadamori 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Inc. (72) Hirotaka Kameya 502, Kandate-cho, Tsuchiura-shi, Ibaraki, Japan Hitachi, Ltd. Within the Machinery Research Laboratory (72) Inventor Yukio Takahashi 2520, Ojitakaba, Hitachinaka-shi, Ibaraki F-term in the Automotive Equipment Division of Hitachi, Ltd. CC22 DD02 DD04 DD05 DD07 DD08 DD10 DD11 DD12 DD13 DD17 DD18 DD22 DD25 DD26 DD27 DD34 DD38 3H084 AA24 AA 45 AA51 AA55 BB04 BB07 BB09 BB11 BB12 BB16 BB23 BB24 BB25 BB26 BB27 BB30 CC03 CC25 CC46 CC51 CC52 CC56 CC58 CC59 CC70

Claims (8)

[Claims] The present invention comprises: a case forming a closed space; and a gear arranged so that teeth provided on an outer periphery in the case mesh with each other and rotate, and the gear includes one of the meshing portions. A pump unit that constitutes a pump unit that sucks fluid from one side and raises the pressure and discharges the fluid to the other side, wherein the pump unit forms a plurality of pump units by meshing a plurality of gears with a common gear; A gear pump characterized in that a plurality of pump sections are connected in series to form a multi-stage pump section. 2. A case having a suction port and a discharge port and forming a closed space, and a gear arranged so that teeth provided on an outer periphery in the closed space of the case mesh with each other and rotate. Wherein the gear constitutes a pump unit that sucks fluid from one side of the meshing unit and pressurizes and discharges the fluid to the other side. The pump unit has a suction side connected to the suction port, and a discharge side includes the discharge port. In the gear pump communicated with a port, the pump unit forms a plurality of pump units by meshing a plurality of gears with a common gear, and connects the plurality of pump units in series via a closed space of the case. A gear pump comprising a plurality of pump sections. 3. A case forming a closed space, a gear arranged so that teeth provided on an outer periphery in the case mesh with each other and rotate, and the gear is sandwiched so as to be rotatable and slidable. And a side plate, wherein the gear is a gear pump comprising a pump unit that sucks fluid from one side of the meshing unit and pressurizes and discharges the fluid to the other side, wherein the pump unit includes a plurality of common gears. A plurality of pump portions are formed by meshing gears, the plurality of pump portions are connected in series to form a plurality of stages of pump portions, and the side plate is provided across the gears forming the plurality of pump portions. And gear pump. 4. A case having a suction port and a discharge port to form a closed space, and a gear arranged so that teeth provided on an outer periphery in the closed space of the case mesh with each other and rotate. A seal block that seals a tooth tip of the gear, wherein the gear constitutes a pump unit that sucks fluid from one side of the meshing unit and pressurizes and discharges the fluid to the other side, and the pump unit has a suction side. In a gear pump connected to the suction port and having a discharge side connected to the discharge port, the pump unit forms two pump units by meshing two gears with a common gear. Are connected in series to form a two-stage pump section, the seal block is provided on the first-stage suction side of the pump section to form a suction passage, and the second-stage discharge side of the pump section is provided. The seal block And a discharge passage is formed, the suction passage is connected to a suction port of the case, and the discharge passage is connected to a discharge port of the case. 5. A case having a suction port and a discharge port and forming a closed space, and a gear arranged so that teeth provided on an outer periphery in the closed space of the case mesh with each other and rotate. The gear includes a side plate that rotatably slidably sandwiches the gear, and a seal block that seals a tooth tip of the gear, wherein the gear sucks up fluid from one side of its meshing portion and pressurizes and discharges the fluid to the other side. A pump unit having a suction side connected to the suction port and a discharge side connected to the discharge port, wherein the pump unit meshes two gears with a common gear. A total of two pump sections are formed, and the two pump sections are connected in series through the closed space of the case to form a two-stage pump section. Provide a seal block and suck A pumping passage, and
The seal block is provided on the discharge side of the step to form a discharge passage, the suction passage is connected to a suction port of the case, the discharge passage is connected to a discharge port of the case, and the side plate is A gear pump, wherein the gear pump is provided so as to straddle the gears forming the pump units. 6. A case having a suction port and a discharge port and forming a closed space, and a gear arranged so that teeth provided on an outer periphery in the closed space of the case mesh with each other and rotate. A pair of side plates that sandwich the gear so as to be rotatable and slidable, and a seal block that seals the tooth tip of the gear, wherein the gear has a drive gear whose both shafts are supported by the case, And a driven gear rotatably supported by the side plate, and constitutes a pump unit that sucks fluid from one side of the meshing unit and pressurizes and discharges the fluid to the other side. In a gear pump connected to a suction port and having a discharge side communicated with the discharge port, the pump section forms two pump sections by meshing the drive gear with two driven gears. Closed the pump section A two-stage pump unit is connected in series via a chain space, and the seal block is provided on the suction side of a first-stage pump unit constituted by one of the driving gear and the driven gear to form a suction passage. The seal block is provided independently on the discharge side of a second-stage pump unit constituted by the driving gear and the driven gear, to form a discharge passage, and the suction passage is connected to a suction port of the case. Pressing means for connecting the discharge passage to the discharge port of the case, introducing high pressure in the discharge passage to the counter gear side of the seal block forming the discharge passage, and pressing the seal block toward the gear. Provided, the thickness of the two seal blocks equal to the thickness of the gear,
The side plate forming the drive gears forming two pump portions;
The low pressure portion communicating with the suction passage and the pressure portion in the case are sealed on the opposite gear side of the side plate on the opposite gear side of the side plate. A first seal member, and a second seal member for partitioning and sealing a high-pressure portion communicating with the discharge passage and a pressure portion in the case, and a shaft of the drive gear is provided by the first seal member. A gear pump, wherein the three gears are arranged so as to surround the low pressure region so that the positions of their axes form a substantially triangular shape. 7. A fuel tank comprising: a fuel tank; a feed pump for increasing the pressure of the fuel in the fuel tank; and a fuel supply pump for further increasing the pressure of the fuel increased by the feed pump and supplying high-pressure fuel to a fuel injection valve of the engine. The gear pump includes a case that forms a closed space, and a gear that is disposed so that teeth provided on an outer periphery in the case mesh with each other and rotate, and the gear includes one of the meshing portions. In a fuel supply device comprising a pump unit that sucks fluid from one side and raises the pressure and discharges the fluid to the other side, the pump unit of the fuel supply pump includes a plurality of gears meshed with a common gear to form a plurality of pumps. The fuel supply device is formed, and the plurality of pump units are connected in series to form a multi-stage pump unit. 8. A case forming a closed space, and a gear disposed so that teeth provided on an outer periphery in the case mesh with each other and rotate, and the gear includes one of the meshing portions. A motor drive unit configured to rotate by supplying fluid from one side and discharging to the other side, wherein the motor drive unit includes a plurality of motor drive units that engage a plurality of gears with a common gear. Wherein the plurality of motor drives are connected in series to form a plurality of stages of motor drives.