JPH0486377A - Radial type piston pump for low viscosity fuel oil - Google Patents

Abstract

PURPOSE:To effectively force feed a low viscosity fuel oil at high speed by successively sucking the low viscosity fuel oil into a ring chamber and a pressurizing chamber from an intake port, moving a piston by the high-speed rotation of a pump shaft, pressurizing the low viscosity fuel oil, and discharging the oil from a discharge port. CONSTITUTION:When an intake port member 17 is connected to a tank for low viscosity fuel oil, a low viscosity fuel oil pressure is passed through a filter 170 and run into a ring chamber 13 from an intake passage 16 through a radial passage 160. When an engine is then driven, a pump shaft F is rotated through a driving pulley G while being supported by radial bearings 11, 12 provided on a housing B and a cover C, and diffusion pump systems 9e, 9f are also rotated. A plurality of cap pistons 3 radially provided in a cylinder A are reciprocated, and the low viscosity fuel oil is run into a pressurizing chamber 30 laid in a negative pressure, and enhanced in pressure. Thereafter, the high pressure low viscosity fuel oil is sent from a ring collective hole 23 to a discharge port member 26 through a discharge passage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radial piston bomb, and particularly to a radial piston pump suitable for pumping low-viscosity fuel oil under high pressure.

[Conventional technology and its technical issues]

As a countermeasure against pollution caused by exhaust gases from internal combustion engines such as vehicles and resource depletion, it is said that it is effective for Kallin to atomize the spray by increasing the pressure. As an alternative fuel, the use of methanol or something similar (hereinafter simply referred to as methanol) is being considered. Since this methanol has poor cold startability, it is necessary to atomize it by increasing the pressure. To achieve this, the discharge pressure of a normal fuel pump of this type is 3-4 kgf/cfl, which is impossible, and the discharge pressure is 70-100 kgf/cfl.
A pump that can deliver a high-speed discharge pressure performance of kg f/a+T is required.

As one type of such a fuel pump, a radial piston pump can be considered in terms of capacity and efficiency. However, the conventional radial type bis I/N pump was developed in Japanese Patent Application Laid-Open No. 64
．． - As shown in Publication No. 367, it is a rotary type in which the cylinder block rotates, and it uses high viscosity oil (viscosity is 30c).
It was generally used as a pressure-feeding means. Furthermore, as a radial piston pump, there is also a fixed cylinder type.

However, the fuel oil has a very low viscosity of about 0.5 cst, and if an attempt is made to pump the fuel oil with such characteristics by rotating the pump shaft at high speed using the powerful power of the engine, If the oil seal on the outer periphery of the pump shaft is strongly tightened, resistance to the rotational torque will occur, so the sealing pressure of the oil seal cannot be increased. As a result, in the prior art, combined with deterioration of the oil seal, fuel oil leaks to the outside, and the grease sealed in the bearing of the pump shirt I is washed and diluted with low viscosity oil, causing seizure, and the piston. between cylinder barrels,
It is not possible to eliminate the risk of galling or seizure occurring between the eccentric cam and the tip of the piston. For this reason, conventional radial piston pumps have been unable to smoothly and stably pump low-viscosity fuel oil at high pressure.

The present invention was devised to solve the above-mentioned problems, and its purpose is to prevent low-viscosity fuel oil, such as gasoline or methanol, from leaking externally from an oil seal. 70kg with good sealing performance
The object of the present invention is to provide a practical radial type bis-one pump capable of high-speed pumping at pressures higher than f/cJ.

[Means to solve the problem]

To achieve the above object, the present invention provides a pump having a fixed cylinder and a plurality of pistons arranged radially in the fixed cylinder, in which these screws are reciprocated by rotation of an eccentric cam of a pump shaft. A housing having a suction bow I- and a cover having a discharge port are integrally connected to the front and rear of a cylinder having a plurality of pistons, and a pump shaft having an eccentric cam is connected to the cover and a bearing in the housing. be supported by,
An annular chamber is formed between the outer periphery of the pump shaft including the outer periphery of the eccentric cam and the inner wall of the cylinder and housing, and the annular chamber stores the low-viscosity fuel oil that has passed through the suction port 1-.
The housing has a radial passage with the annular chamber as part of the flow path for sucking low-viscosity fuel oil into the suction hole of each piston, and low-viscosity fuel oil and bearing grease are arranged in the axial direction of the annular chamber. An oil seal is provided to cut off the mixing of the oil, and a diffusion pump mechanism is provided on the outer periphery of the pump shaft near this oil seal.

[For production]

The low-viscosity fuel oil flows from the suction port into the annular chamber via the radial passages, and while it accumulates there, it is sucked into the pressurizing chamber from each radial passage through the respective suction passages, and due to the high speed rotation of the pump shaft, it is As the piston in contact with the eccentric cam moves, the low-viscosity fuel oil is pressurized and discharged from the discharge port.

Both sides of the annular chamber in the axial direction are sealed with oil seals, and the low-viscosity fuel oil is subjected to the required oil pressure. Therefore, there is a risk that the oil seal may leak to the outside due to deterioration or the like.

However, in the present invention, a diffusion pump mechanism is provided on the outer circumference of the pump shaft near the oil seal, and this pump mechanism rotates when the pump shaft rotates, displacing low-viscosity fuel oil near the oil seal, and displacing the low-viscosity fuel oil near the oil seal. Relatively lower the pressure of the low-viscosity fuel oil on the nearby side.

This prevents low-viscosity fuel oil from leaking from the oil seal, and prevents dilution of the grease on the bearing side.
It is possible to prevent accidents such as fires due to fuel leakage. In addition, the pump mechanism agitates the low-viscosity fuel oil in the annular chamber and improves its flow, thereby suppressing the rise in fuel temperature and achieving good lubrication and cooling of the eccentric cam and pump shaft.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 10 show a first embodiment of a radial piston pump according to the present invention, and FIG. 12 shows a second embodiment of a radial piston pump according to the present invention.
An example is shown.

In FIGS. 1 and 2, A is a cylinder, and B is a housing, which is in contact with one end surface of the cylinder A in the axial direction via a leaf valve D and a gasket E. A cover C is in contact with the other end surface of the cylinder A in the axial direction via a leaf valve D' and a gas scale L-E'.

The cylinder A, the housing B, the cover 〇, the leaf valves D, D' and the gasket E' each have a plurality of pin insertion holes 100 and a plurality of pin holes 101 (five in the illustration), and the housing B are threaded holes), and positioning in the circumferential direction is achieved by fitting pins 102 into these pin insertion holes ]00, and by passing stud ports 1-1-03 through holes 1 to 1O1 and tightening them. It is integrated by

F is a pump shaft, which is rotated via a drive pulley G by the drive of an external engine.

The recordable cylinder A has a cylindrical shape as shown in FIGS. 1, 3, and 4, and has a plurality of cylinder holes 2 (five in this example) penetrating from the inner wall 1 to the outer wall. are formed radially at equal intervals, and cap-shaped screws 3 are slidably fitted into each cylinder hole 2. It is biased in the centripetal direction by a spring 5 whose one end is supported by 4.

The housing B has a cylindrical shape, and has an inner wall 6 having a diameter that matches the inner wall 1 of the cylinder A, as shown in FIG. .

The cover O is concentric with the cylinder A and the housing B, and has a small diameter stepped blind hole 8 formed therein.

As shown in Fig. 1, the pump shaft F includes a narrow diameter portion 9a from the tip to the rear, an eccentric cam portion 9b located at a position corresponding to the cylinder area, a large diameter portion 9c concentric with the narrow diameter portion 9a, and a stepped portion. It has a diameter portion 9d, and the narrow diameter portion 9a is stopped by a thrust bearing 10 placed at the bottom of the stepped blind hole 8, and is supported by a radial type bearing 11 placed on the inner periphery of the hole. The stepped diameter portion 9d is supported by a radial bearing 12 disposed in the enlarged hole 7.

The eccentric cam portion 9b and the large diameter portion 9c have a diameter smaller than the inner walls 1 and 6 of the cylinder A and the housing B, and the eccentric cam portion 9
An annular chamber 13 for storing low-viscosity fuel oil is formed between each outer periphery of the large-diameter portion 9c and the inner walls 1, 6 of the cylinder A and the housing B.

In the axial direction of this annular chamber 13, oil seals are provided in each area of the stepped blind hole 8 and the enlarged hole 7]4.
Separated from the bearing side by 15, radial bearing 11.12
This prevents the grease sealed in the tank from being diluted with low-viscosity fuel oil, which has cleaning properties.

Furthermore, the present invention provides a narrow diameter portion 9 near the oil seal 14.
Region a and Oil Seal] Diffusion pump mechanisms 9e and 9f are provided in the region of the large diameter portion 9c near the oil seal 5, respectively.

In the first and second embodiments, the pump mechanisms 9e and 9f are made separately from the pump shirt 1-F, and are fitted and fixed to the pump shaft F by a method such as a key or press fit. Pump mechanism 9
The pump mechanism 9f is configured as an impeller having a plurality of radial vanes 95 as shown in FIGS. It is configured as an impeller having a plurality of spiral blades 96 facing toward the oil seal side. Of course, the pump mechanism 9e
may be an impeller having a plurality of spiral blades, and the pump mechanism 9f may be an impeller having radial blades 95. Furthermore, in the first embodiment and the second embodiment, the pump mechanisms 9e, 9
At least one of f may be formed integrally with the pump shaft F.

As shown in FIGS. 1 and 3, the eccentric cam portion 9b is integrally formed with a cam body 90 and a metal bush 9 fitted externally so as to be relatively rotatable to the metal bush 91 by any method such as press fitting. The guide ring 92 has a high hardness (of course, it may be a separate part), and the curvature tip of the cap-shaped screw hem 3 comes into contact with the guide ring 92.

The metal bush 9] and the guide ring 92 are prevented from moving at the right end by a large diameter portion 9c, and at the left end by a retaining ring 93 attached to the main body 90 of the force 11. Although not shown, the metal bush 91 has a minute spiral oil groove formed on its inner surface, and the flow of low-viscosity fuel oil through the spiral oil groove provides lubrication between the metal bush 91 and the cam body 90.

The highly hard guide ring 92 is made of, for example, SUJ material or fine ceramics. The main body 90 of the force 11 may be formed integrally with the pump shirt l-F as shown in FIG. 1, and may be constructed by hardening the surface, or may be formed separately from the pump shaft F as shown by the imaginary line in FIG. It may also be integrated by press-fitting and a key.

A pressurizing chamber 30 with an enlarged diameter is formed in the cylinder hole portion corresponding to the upper end portion of each cap-shaped screw hem 3, and the right end surface of the cylinder corresponding to each pressurizing chamber 30 is shown in FIG. As shown in FIG. 4, a counterbore hole 31 is formed through the suction side passage hole 33 that communicates with the pressurizing chamber 30, and a hole is formed on the left end surface of the cylinder between the suction side passage hole 33 and the wound side. A discharge side passage hole 34 is bored.

- On the other hand, the housing B is provided with suction passages 6 which are opened on the left end surface as shown in FIGS. 1 and 5 at positions corresponding to the counterbore holes 31, respectively. The suction passage 16 is bent at the rear side and communicates with the annular chamber 13 as a radial passage 1.60, from which low-viscosity fuel oil is sucked.

One suction passage 16 has an internal filter] 70.
The suction port member 17 is connected to a low viscosity fuel oil tank by a conduit (not shown).

As is clear from FIGS. 4 and 8, each of the suction passages 16 communicates with the through holes 1-8 provided in the gas keratin I-E,
Further, the tip thereof is closed by a suction valve 19 made of a tongue-shaped spring disposed on the leaf valve D. Figure 10(a) shows Gaskera 1-E;
b) shows the leaf valve D.

In each of the counterbore holes 31, there are holes 1 to 2 that catch the intake valve 19 of the leaf valve D when it is opened.
0 is inserted. The stopper 20 is shown in FIGS.
As shown in the figure, the width is narrow so as to leave a gap between it and the inner wall of the counterbore hole, and the side of the counterbore hole 31 facing the igneous area has an oil passage hole that almost matches the suction side passage hole 33. Groove 200
is formed, and in order to set this positional relationship, it is positioned and held in the cylinder 8 by a pin 21. It is preferable that the suction valve 19 of the leaf valve D has substantially the same width as the stopper 20, as shown in FIG.

On the other hand, as shown in FIGS. 6 and 7, the tip of the discharge side passage hole 34 is a through hole E' to the gas cellar l of the same configuration as shown in FIG. 10(b) except that the center hole diameter is different. 8', the end of which is normally closed by a discharge valve 19' of the first valve D' as shown in FIGS. 6 and 7. The leaf valve D' has the same structure as that shown in FIG. 10(a), that is, it is a shared part.

On the other hand, on the right end surface of the cover C, a counterbore hole 31' is formed at the same position in the radial and circumferential direction as the counterbore hole 31, and each counterbore hole 31' is provided with the stopper 20.
A stopper 2Q' having the same structure is fitted and held in position on the cover C by a pin 21'. A discharge hole 23 is formed at the bottom of each counterbore hole 31', and these discharge holes 23 are connected in an annular manner by a collecting hole 24 as shown in FIG. As shown in the figures and Fig. 7, a discharge passage 25 extending in the axial direction of the cover is connected, and the tip of the discharge passage 25 communicates with the discharge ports 1 to 26 inserted in the cover 〇, and high-pressure discharge is supplied to an injection system, etc. (not shown). It is designed to supply oil.

A relief valve 27 is provided in the middle of the discharge passage 25 as shown in FIG. This relief valve 27 has a side valve 27) whose opening pressure is adjusted by a spring 27a, and a return hole 260 communicating with the annular chamber 13 is bored in the valve opening position.

Note that the cap-shaped piston 3 may be provided with a fine passage hole 300 penetrating the tip of the curvature, if necessary, so that a portion of the fuel oil in the pressurizing chamber 30 is transferred to the guide 1 (ring 92). Since it is guided to the contact surface with the surface, the lubricity can be further improved.

Note that what is illustrated is an example of the present invention, and Gaskera h
E, E' may be placed on both sides with leaf valves D, D'' in between, or conversely, gaskets E,
E' may be omitted.

In the second embodiment shown in Fig. 12, on the discharge side, a leaf valve D' is interposed between the cylinder A and the cover 〇 via a gas scale L-E' as in Fig. 6 of the first embodiment. However, the discharge side passage hole 34 and the discharge hole 23 are communicated with each other by a tongue-shaped discharge valve 19', but the passage is opened and closed by the movement of the screw 1-3 itself instead of using a leaf valve system. I try to let them do it.

That is, in this second embodiment, the cylinder A and the housing B are connected via the gasket E, and the pressurizing chamber 30 of the cylinder A has a suction side path hole such that one end thereof communicates with the through hole 18 of the gas keratin I-E. 33 are drilled. The opening of the suction side path hole 33 is closed by the piston circumferential surface when the piston reaches the -1- dead center position as shown in the upper side of FIG. It is provided in such a manner that it is opened apart from the circumferential surface. .

Therefore, the effective stroke is from the position where the piston moves and closes the suction side path hole 33 to the top dead center position. The rest of the structure is the same as in the first embodiment, so the same parts are denoted by the same reference numerals and the explanation will be omitted.

[Effect of the embodiment]

In use, the suction boat member 17 is connected to a tank of low viscosity fuel oil, and the member 25 is connected to the discharge port 1 with an injection system. The low viscosity fuel oil passes through the filter 170, flows from the suction passage 16 through the radial passages 160 into the annular chamber 13, and then flows from the annular chamber 13 through the respective radial passages 160 to each suction passage 16. At this time, in the eleventh embodiment, the suction valve] 9 of the leaf valve D is closed by the spring force, and in the second embodiment, the suction side path hole 33 is closed by the piston 3, so that the low viscosity fuel Oil does not flow into the pressurizing chamber 30. In addition, since the pump shaft is not rotating at this time, the pump mechanism 9e for diffusion
, 9f have also stopped operating. During this stop, the feed pressure is zero, so the oil seal 14. ．． 15 is under no load and there is little risk of fuel leakage.

When the engine is activated immediately, power is transmitted to the pump shaft F via the instant-acting pulley G, and the pump shirt I-T? are radial bearings 11 and 12 installed in housing B and cover 〇.
The diffusion pump mechanisms 9e and 9f provided on the pump shaft F also rotate at the same time. The annular chamber 13 is not only always closed on both sides by oil seals 14 and 15, but also by the diffusion pump mechanism 9e.

The low viscosity fuel oil is diffused as 9f rotates, and in the former = 16 pump mechanism 9e, a centrifugal force is applied to the low viscosity fuel oil, forcing it against the cylinder inner wall. The latter pump mechanism 9f provides displacement in the axial direction accompanied by centrifugal force. For this reason, the fuel pressure acting on the oil seals 14, 15 decreases, and the oil seals 14, 1.5 do not need to be tightly tightened, or due to deterioration or the like, the oil seals 1.
Even if the sealing performance of 4.15 is degraded, the low-viscosity fuel oil will not flow into the outside, that is, the radial bearing side, and therefore the grease will not be diluted by the cleaning action of the low-viscosity fuel oil, resulting in good lubrication. can maintain its condition.

Due to the high-speed rotation of the pump shaft F as shown in (h), a plurality of cap-shaped pistons 3 arranged radially within the cylinder A reciprocate. That is, each cap-shaped piston 3 is always pressed against the eccentric cam part 9b by the spring 5, so that when the eccentric cam part 9b rotates from the top dead center toward the bottom dead center, the cap-shaped piston 3 moves to the top dead center. The pressurizing chamber 30 becomes a negative pressure. This negative pressure creates a pressure difference with the suction passage 16, and in the first embodiment, the suction valve 9 of the leaf valve (2) is opened in response to this pressure difference. In the second embodiment, when the screw 1 is lowered one step, the upper end of the screw 1 is exposed through the suction passage hole 33, so that it communicates with the suction passage 16.

As a result of the above operation, in the first embodiment, the low viscosity fuel oil enters the counterbore hole 31 from the side of the suction valve 19, flows into the pressurizing chamber 30 from the suction side passage hole 33 via the oil passage groove 200, and enters the pressurizing chamber 30. In the second embodiment, the air flows directly into the pressurizing chamber 30 from the suction side path hole 33. Note that the discharge valve 19' is closed by its own spring force and the negative pressure of the pressurizing chamber 30.

The low viscosity fuel oil that has entered the pressurizing chamber 30 is transferred to the eccentric cam part 1.
．． The suction stroke occurs during rotation of 80 degrees, and the compression stroke occurs between 180 and 360 degrees, resulting in high pressure.

In this compression stroke, that is, the first upward stroke of the piston,
In the first embodiment, the suction valve 19 is closed by pressure in the pressurized chamber,
The discharge valve 19' is opened. In addition, in the second embodiment, as the piston 3 rises, the communication between the suction side path hole 33 and the pressurizing chamber 30 is temporarily interrupted and cut off, and the area from this position to the top dead center position is the effective loaf. Become.

In any case, the high-pressure low-viscosity fuel oil enters the counterbore hole 31' from the discharge side passage hole 34 through the side of the discharge valve 19', and is discharged into the discharge hole 23 through the oil passage groove 200. The fuel oil is discharged from the annular collecting hole 23 through the discharge passage 25 to the discharge port member 26, so that the low viscosity fuel oil can be injected into the engine cylinder or the like in a well atomized state.

When the low viscosity fuel oil becomes abnormally high pressure, the relief valve 27 is opened by the discharge pressure, and the high pressure is returned to the annular chamber 13 through the return hole 260.

The cap-shaped piston 3 becomes high pressure because it compresses low-viscosity fuel oil, and comes into point contact with the guide ring 92 due to the reaction force. Since this contact pressure is very high, relative slippage is unlikely to occur between the curved tip of the screw 1 and the guide ring 92, and therefore, wear can be suppressed.

The relative rotation between the cap-shaped piston 3 and the pump shirt l-F is performed by line contact between the cam body 90 and the metal bush 91, and the cam body 90 and the metal bush 9-]9-1 can be set to an appropriate length. The overall surface pressure can be lowered.

When the pump shirt I-F rotates at high speed, high heat is generated on the sliding surface between the cam body 90 and the metal bushing 91, but the metal bushing 91 is immersed in low-viscosity fuel oil in the annular chamber 13, and the suction port The low viscosity fuel oil from the member 17 passes through the annular chamber 13 and is sucked into the respective suction passage 16 via each radial passage 160. That is, the annular chamber 13 functions as a part of the suction passage. Furthermore, in accordance with the rotation of the pump shaft F, the diffusion pump mechanisms 9e and 9f integrated therewith diffuse the low-viscosity fuel oil within the annular chamber. Therefore, low viscosity fuel oil does not stagnate.
Also, the rise in fuel temperature is suppressed. Therefore, it is possible to perform good cooling and lubrication between the cam body 90 and the metal bush 91, and also to provide good cooling and lubrication between the guide link 92 and the pump shirt 1F.

According to the first embodiment, even if the piston 3 is worn out, the suction side passage hole 33 is always connected to the pressurizing chamber 3 via the leaf valve D.
Since it is sucked smoothly to 0, there is an advantage that the effective stroke does not change. According to the second embodiment, the leaf valve on the suction side, the collar 20, the counterbore 31, and the pin 21 can all be omitted, so the mechanism can be significantly simplified.

In addition, when the force 11 main body 90 is made separately as the eccentric cam part 9b, several sets of assemblies of the cam main body 90, metal bushing 91, and guide ring 92 with different wall thicknesses are prepared.
By appropriately replacing the pump shirts I-F, the piston I-loak, that is, the discharge amount can be changed without changing the pump shirts I to F.

〔Effect of the invention〕

According to the radial piston pump of the present invention as described above, low-viscosity fuel oil such as gasoline or methanol can be used without causing fuel leakage from the oil seal, accompanying galling, seizure, or external leakage. ,7
The excellent effect of high-speed pumping by pumping to a high pressure of 0 kgf/d or more can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view showing a first embodiment of the radial pump according to the present invention, Fig. 2 is an exploded perspective view thereof, Fig. 3 is a sectional view taken along line m-m in Fig. 1, Figure 4 is a partially cutaway front view of the cylinder, Figure 5 is a partially cutaway rear view of the housing, Figure 6 is a partially cutaway front view of the cover, Figure 7 is a sectional view taken along line ■-■ in Figure 6, and Figure 8 is a partially cutaway front view of the cylinder. The figure is an enlarged cross-sectional view of the suction passage portion, Figure 9 is a cross-sectional view taken along line IX-IX in Figure 8,
Figure 0(a) is a front view of the relief valve, Figure 10(b)
11 is a sectional view showing another embodiment of the diffusion pump mechanism according to the present invention, and FIG. 12 is a longitudinal sectional side view showing a second embodiment of the present invention. A. Cylinder, B..Housing, C..Cover D.
D'... Leaf valve, E, E' ・To gaskera 1, F... Pump shaft, 1, 6... Inner wall, 9b ・
Eccentric cam part, 9e, 9f...pump mechanism for diffusion, 1
1゜12... Radial bearing, 13... Annular chamber, 14,
1.5 oil seal, 16... suction passage, 17...
Suction port member, 30 Pressurizing chamber, 33 Suction survey road hole, 34 Discharge side passage hole, 160 Radial passage Patent applicant Diesel Kiki Co., Ltd.

Claims (1)

[Claims] A pump having a fixed cylinder and a plurality of pistons arranged radially in the fixed cylinder, and in which these pistons are reciprocated by the rotation of an eccentric cam of a pump shaft. A housing having suction ports and a cover having a discharge port are combined at the front and rear of the cylinder, and a pump shaft having an eccentric cam is supported by the cover and a bearing in the housing, and the outer circumference of the pump shaft including the outer circumference of the eccentric cam and the outer circumference of the pump shaft include the outer circumference of the eccentric cam. An annular chamber is formed between the cylinder and the inner wall of the housing to store low-viscosity fuel oil that has passed through the suction port, and the housing uses the annular chamber as part of a flow path to inhale low-viscosity fuel oil into each piston. A radial passage is drilled to allow suction into the hole, and an oil seal is installed in the axial direction of the annular chamber to prevent the mixing of low-viscosity fuel oil and bearing grease.In addition, a radial passage is installed on the outer circumference of the pump shaft near this oil seal for diffusion. A radial piston pump for low viscosity fuel oil that is equipped with a pump mechanism.