JPH05256252A - Radial piston pump for fluid of low viscosity - Google Patents

Abstract

PURPOSE:To prevent external leakage of low viscous fluid in a fluid reservoir chamber by closing an end part of a pump housing by a nonmagnetic partition, and driving a drive mechanism and a drive shaft connected with the partition spaced by a magnetic coupling. CONSTITUTION:A magnet coupling 30A is fixed to a drive side end part 21 of a pump drive shaft 20 and housed in a coupling storage hole 111 by providing a little space with a partition 300 formed of nonmagnetic material. A magnet coupling 30B is fixed to an end part 221 of a pulley shaft 220 and housed in a storage hole 203. Consequently, when the pulley shaft 220 is rotated, the rotation of the magnet coupling 30B is transmitted to the magnet coupling 30A to rotate the drive shaft 20. On the other hand, a part between an inlet side block 110 and the partition 300 is sealed by a seal ring 13. Accordingly, A leakage to the outside can not be generated of gasoline leaked to the coupling storage hole 111.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial piston pump suitable for pumping low viscosity fluid under high pressure.

[0002]

2. Description of the Related Art In recent years, improvement of combustion efficiency has been demanded as a countermeasure against pollution problems caused by exhaust gas from internal combustion engines such as vehicles and resource depletion. As a countermeasure, when using gasoline, methanol, alcohol, or the like as a fuel, it is effective to increase the pressure of the fuel to improve atomization of the spray. To achieve this, the discharge pressure must be 70
A fuel pump capable of exhibiting a high discharge pressure performance of up to 100 Kgf / cm ² was required, and the radial piston pump was suitable in view of performance and efficiency.

A conventional radial piston pump has a high-viscosity oil as disclosed in JP-A-64-367.
It is generally used as a pressure-feeding means (having a viscosity of 30 cst or more), and has not been used for pressure-feeding a low-viscosity oil such as gasoline, methanol or alcohol. This is because the sliding part between the piston and the cylinder and the contact part between the eccentric cam and the piston cause galling and seizure, and the low viscosity oil dilutes the grease enclosed in the bearing that supports the drive shaft. This is because there is a problem of cleaning.

Therefore, the applicant of the present invention has developed a radial piston pump suitable for pressure-feeding low-viscosity oil. This is as disclosed in Japanese Patent Laid-Open No. 3-175158. That is, an annular fuel pool chamber is provided around the drive shaft in the pump housing, and the low viscosity oil is circulated in the fuel pool chamber as a part of the inflow passage, which may cause galling or seizure. The low viscosity oil was used to cool and lubricate some of the parts.

The drive shaft is rotationally driven by a drive mechanism from outside the pump housing. That is,
The drive-side end of the drive shaft is projected out of the pump housing, a pulley is fixed to the protruding end, and this is rotated by a belt. By the way, low-viscosity oil such as gasoline is highly flammable and dangerous if leaked to the outside.Therefore, install a seal member between the pump housing and the drive shaft to prevent low-viscosity oil from leaking from the fuel reservoir. There is.

[0006]

However, in the seal structure for preventing low-viscosity oil leakage in the improved radial piston pump described above, a complete seal is not possible as long as the seal member and the drive shaft rotate relative to each other. There was a risk that low-viscosity oil would leak to the outside during this period.
The present invention has been made in view of the above-mentioned problems of the conventional technology, and an object thereof is to provide a highly safe low-viscosity radial that can reliably prevent external leakage of a low-viscosity fluid. It is about to provide a piston pump.

[0007]

The present invention has been made in order to achieve the above-mentioned object, and the gist thereof is that a drive shaft installed inside a fixed pump housing is installed outside the pump housing. The radial piston for low-viscosity fluid, which is rotated by a drive mechanism, reciprocates a plurality of pistons radially arranged around the eccentric cam by an eccentric cam provided on the drive shaft, and boosts the low-viscosity fluid. In the pump, an annular fluid collection chamber forming a part of an inflow passage of a low-viscosity fluid is provided around an eccentric cam in the pump housing, and an end portion of the pump housing which accommodates a drive side end portion of the drive shaft, It is sealed by a partition wall made of a non-magnetic material fixed to the end portion, and the drive-side end portion of the drive shaft and the drive mechanism are arranged with the partition wall therebetween. A low viscous fluid radial piston pump, characterized by being cooperative with magnetic coupling have.

[0008]

The partition and the pump housing are both fixed systems, and it is possible to reliably seal between them by a seal member. Therefore, it is possible to reliably prevent external leakage of the low-viscosity fluid. The rotation of the drive mechanism is transmitted to the drive shaft by the magnetic coupling.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings from FIG. 1 to FIG. FIG. 1 is a vertical sectional view of a radial piston pump for gasoline (for low viscosity fluid) according to the present invention. This radial piston pump includes a coupling housing 200, a partition wall 300, and an inlet side block 1.
10, the distribution plate 120, the cylinder 130, and the outlet-side block 140 are connected and fixed by an outer cylinder 400 arranged outside thereof. The inlet block 110, the distribution plate 120, the cylinder 130, and the outlet block 140 constitute the pump housing 100.

The inlet side block 110 is provided with a coupling receiving hole 111, a bearing mounting hole 112, an oil seal mounting hole 113, and a low pressure pump storing hole 114 in order from the right side in the drawing. On the other hand, the outlet block 140 is provided with a bearing mounting hole 141 and a return passage hole 142 in order from the right side. The radial bearings 10 and 11 are fitted in the bearing mounting holes 112 of the inlet block 110 and the bearing mounting holes 141 of the outlet block 140, respectively, and the radial bearings 10 and 11 penetrate the distribution plate 120 and the cylinder 130. The drive shaft 20 is rotatably supported.

A drive side end portion (right end in the figure) 21 of the drive shaft 20 projects into the coupling receiving hole 111, and a magnetic coupling 30 is attached to the drive side end portion 21.
A is fixed. Magnet coupling 30A
Is composed of a disk-shaped holder 33 fixed to the drive-side end portion 21 by a key 31 and a nut 32 in a non-rotatable manner, and a magnet 34 provided on a surface of the holder 33 facing the partition wall 300. .. The magnet 34 is magnetized to have S poles and N poles alternately in the circumferential direction. The magnet coupling 30A is rotatably accommodated in the coupling accommodating hole 111 with a slight gap between the magnet coupling 30A and the partition wall 300. The partition wall 300 is made of a non-magnetic material, and the space between the inlet block 110 and the partition wall 300 is reliably sealed by the seal ring 13 installed on the opposing surface.

The oil seal 12 is attached to the oil seal attachment hole 113 of the inlet block 110.
In the low pressure pump storage hole 114 of the inlet side block 110,
A vane pump 40 is housed. Vane pump 40
Mainly comprises a rotor 41, a cam ring 42, both side plates 43 and 44, and blades (not shown). Cam ring 42
The side plates 43 and 44 are fixed to the low-pressure pump housing hole 114, while the rotor 41 is fixed to the drive shaft 20 by the key 45 so as to rotate in synchronization with the drive shaft 20.

A suction port 46 provided in the suction side plate 43.
Is the fuel inflow hole 11 provided in the inlet side block 110.
Connected to 5. The fuel inlet 115 is connected to a fuel tank (not shown) via a pipe or the like.

An annular space is formed between the drive shaft 20, the distribution plate 120 and the cylinder 130.
This space serves as a fuel storage chamber (fluid storage chamber) 101. An annular groove 121 is provided on a surface of the distribution plate 120 facing the vane pump 40. Annular groove 121
Is connected to the discharge port 47 provided in the discharge side plate 44 of the vane pump 40, and is connected to the fuel storage chamber 101 by five radially extending vertical grooves 122 provided in the distribution plate 120 at equal intervals in the circumferential direction. There is.

In the drive shaft 20, the cylinder 1
An eccentric cam 22 is provided at a portion arranged inside 30. The eccentric cam 22 is formed on the drive shaft 20 and has a circular cross-section cam portion 23 whose center is eccentric from the rotation center of the drive shaft 20, and is attached to the outside of the cam portion 23 to be rotatable with respect to the cam portion 23. And a cylindrical guide ring 25 attached to the outside of the bush 24 so as to be rotatable relative to the bush 24. When viewed from the side, the outer shape of the guide ring 25 has a regular pentagonal shape as shown in FIG. 2, and the fuel storage chamber 101 is sized so as not to interfere with the eccentric cam 22 when it rotates.

The cylinder 130 is formed with five cylinder holes 131 radially arranged at equal intervals in the circumferential direction, and the tip of each cylinder hole 131 is a recess having a circular cross section formed on the outer peripheral surface of the cylinder 130. It is connected to 132. The piston 50 is slidably inserted in each cylinder hole 131 in the axial direction thereof. Also, each recess 1
A spring retainer 51 having the shape shown in FIG.
It is installed so as to block a part of the opening of 2.
Inside the spring retainer 51, a valve 52 that opens and closes the opening of the cylinder hole 131 on the recess 132 side is movably accommodated.

The valve 52 is biased by a spring 53 arranged between the valve 52 and the spring retainer 51 so as to approach the piston 50. Further, the piston 50 has a cavity 54 inside,
The spring 55 is housed in it. The spring 55 urges the piston 50 and the valve 52 in the directions in which they are separated from each other, and as a result, the piston 50 is moved by the spring 53.
The spring force of the spring 55 urges the drive shaft 20 toward the drive shaft 20. Also, the piston 5
0 is an introduction hole 5 penetrating the cavity 54 from the outer peripheral surface thereof.
6 is provided.

The base end of each piston 50 (drive shaft 2
A shoe 57 having a hole in the center is attached to the (0 side end portion). The shoes 57 are in surface contact with the five flat surfaces forming the outer peripheral surface of the guide ring 25. When the drive shaft 20 rotates, the eccentric cams 22 cause the pistons 50 to reciprocate against the spring force. ..
The piston 50 depicted in FIG. 1 shows a state of top dead center.

An annular communication passage 133 is formed on the outer peripheral surface of the cylinder 130, and the five recesses 132 are connected by the communication passage 133. Communication passage 13
3 is connected to a discharge port 144 provided in the outlet-side block 140 via a passage 134. This discharge port 14
4 is an injection system including a fuel injection nozzle or the like through a pipe or the like
(Not shown).

In each of the cylinder holes 131, a suction hole 135 is opened in the stroke region of the introduction hole 56 of the piston 50. As shown in the detailed view of FIG. 4, this suction hole 1
Reference numeral 35 is connected to a check valve storage hole 136 formed in the end surface of the cylinder 130 on the distribution plate 120 side. On the other hand, the distribution plate 120 has a valve seat hole 124 having a tapered valve seat 123 at a portion facing the check valve housing hole 136.
Is provided. The valve seat hole 124 is continuous with the vertical groove 122.

A spherical check valve 60 and a valve stopper 61 are housed in the check valve housing hole 136. A large number of holes 61a are opened in the valve stopper 61 fixed to the check valve storage hole 136 so that gasoline can always flow. The check valve 60 is biased in a direction of approaching the valve stopper 61 by a spring 62 arranged between the check valve 60 and the discharge side plate 44 of the vane pump 40, and is normally pressed against the valve stopper 61 to open the valve seat hole 124. is doing. Then, when the gasoline in the suction hole 135 rises to a predetermined pressure, the check valve 60 moves in the direction approaching the distribution plate 120 against the elasticity of the spring 62, and the valve seat 1
The valve seat hole 124 is closed by sitting on the seat 23.

In the outlet block 140, a passage 143 is partially provided in the circumferential direction outside the bearing mounting hole 141, and the passage 143 is used to form the fuel storage chamber 101.
And the return passage hole 142 are connected. The return passage hole 142 is connected to the fuel tank via a regulator (not shown).

On the other hand, the coupling housing 200 is provided with an oil seal mounting hole 201, a bearing mounting hole 202, and a coupling accommodating hole 203 from the right side in the drawing.
A double row radial bearing 210 is fitted in the bearing mounting hole 202, and the pulley shaft 220 forming a part of the drive mechanism is rotatably supported by the radial bearing 210.

One end 221 of the pulley shaft 220 projects into the coupling accommodating hole 203.
A magnet coupling 30B which is paired with the magnet coupling 30A is fixed to 21. Since the structure of the magnet coupling 30B is the same as that of the magnet coupling 30A, the same reference numerals are given and the description thereof will be omitted. This magnet coupling 30B is also a partition wall 30.
There is a slight clearance between the coupling receiving hole 20 and
It is housed rotatably in the interior 3.

The other end 222 of the pulley shaft 220 projects outward from the oil seal mounting hole 201, and the pulley P is mounted there. The pulley P is rotationally driven by the engine via a belt or the like. An oil seal 230 is attached to the oil seal attachment hole 201.

By crimping the end portion of the outer cylinder 400 and hooking the crimp portion 401 in the annular recess 204 provided on the outer peripheral surface of the outlet block 200, the end surface of the coupling housing 200 is separated from the partition wall 300. The partition wall 300 is pressed against the end face of the inlet-side block 110, and these are connected and fixed.

A flow of gasoline (low-viscosity fluid) in the gasoline radial piston pump having the above-described configuration will be described.
The engine is driven to rotate the pulley P and the pulley shaft 2
When 20 is rotated, the rotation of the magnet coupling 30B is transmitted to the magnet coupling 30A, and the drive shaft 20 rotates.

Then, the rotor 41 of the vane pump 40 is rotated by the drive shaft 20, and the gasoline in the fuel tank is sucked from the suction port 46 of the vane pump 40. For example, the gasoline whose pressure has been increased to about 1 kgf / cm ² by the vane pump 40 is discharged from the outlet 47 to the distribution plate 120.
Of the valve seat hole 1 through the vertical groove 122.
24, further passes through the check valve storage hole 136 and reaches the suction hole 135. Further, part of the gasoline boosted by the vane pump 40 flows from the annular groove 121 through the vertical groove 122 into the fuel storage chamber 101, and the outlet side block 1
40 through the passage 143 and the return passage hole 142 to return to the fuel tank.

The rotation of the drive shaft 20 causes the eccentric cam 22, the spring 53, and the spring 55 to cooperate with each other to reciprocate each piston 50. That is, each piston 50 sequentially moves from the top dead center to the bottom dead center while the eccentric cam 22 rotates 180 °, and moves from the bottom dead center to the top dead center during the subsequent 180 ° rotation. The former is the inhalation process and the latter is the compression process.

First, the inhalation process will be described. At the initial stage when the piston 50 moves from top dead center to bottom dead center,
The valve 52 closes the cylinder hole 131, and almost at the same time, the introduction hole 56 of the piston 50 makes the intake hole 13 of the cylinder 130.
When they meet 5, they communicate with each other. Introduction hole 56 and suction hole 13
After the communication of 5 with each other, the gasoline flows into the hollow portion 54 of the piston 50 before the piston 50 reaches the bottom dead center.
4 and the inside of the cylinder hole 131 are filled with gasoline.

Next, in the compression process, while the piston 50 moves from the bottom dead center to the top dead center, the gasoline in the cavity 54 and the cylinder hole 131 is compressed. In the initial stage of this compression process, the pressure inside the cavity 54 reaches the operating pressure of the check valve 60, and the check valve 60 seats on the valve seat 123 and closes the valve seat hole 124. Due to the subsequent movement of the piston 50 in the direction of the top dead center, the gasoline in the cavity 54 is rapidly increased in pressure. Then, when the pressure of this gasoline reaches a predetermined valve opening pressure, the valve 52 lifts against the elasticity of the spring 53 and opens the opening of the cylinder hole 131. as a result,
High-pressure gasoline passes from the cylinder hole 131 to the recess 13
2 and then to the discharge port 144 through the communication passage 133 and the passage 134. The gasoline delivered from the discharge port 144 is injected into the engine cylinder in a state where it is finely atomized by the injection system.

In this radial piston pump,
When the drive shaft 20 rotates, the cam portion 23, the bush 24, and the guide ring 25 of the drive shaft 20 slide and rotate, and the sliding portion generates heat. However, the cam portion 23, the bush 24, and the guide ring 25 are immersed in the gasoline flowing into the fuel storage chamber 101, and moreover,
Since the fuel storage chamber 101 forms a part of the intake passage and gasoline always flows, the sliding portions are lubricated and cooled by gasoline. Therefore, it is possible to prevent each of the sliding parts from getting hot.

Particularly, in the case of this embodiment, the pistons 50 receiving the force from the high-pressure gasoline in the cylinder holes 131 respectively press the outer surface of the guide ring 25 having a pentagonal cross section toward the center of the drive shaft 20. As a result, the guide ring 25 cannot rotate. Further, since the cam portion 23 and the bush 24 are relatively rotatable and the bush 24 and the guide ring 25 are relatively rotatable, the sum of these two relative rotational speeds is the drive shaft 20.
Is the number of rotations. Here, since the respective rotation directions should be the same as the drive shaft 20, the respective relative rotation speeds should be lower than the rotation speed of the drive shaft 20. Therefore, heat generation itself in these sliding portions can be suppressed low.

By the way, in this radial piston pump, the inside of the fuel storage chamber 101 has a positive pressure. Therefore,
Although there is a little gasoline in the fuel storage chamber 101, a gap between the drive shaft 20 and the side plate 44 of the vane pump 40, a gap between the key groove and the key 45 provided in the drive shaft 20 and the rotor 41, a gap between the drive shaft 20 and the side plate 43. Leakage in the direction of approaching the radial bearing 10 through the gap.

An oil seal 1 is provided in front of the radial bearing 10.
2 is installed, but as long as the drive shaft 20 slides and rotates the oil seal 12, it is impossible to completely seal the oil seal 12. Therefore, the leaked gasoline is
There is a risk that the oil may leak into the bearing mounting hole 112 through the gap between the oil seal 12 and the drive shaft 20 and further into the coupling housing hole 111.

However, the coupling receiving hole 111
Is closed by the partition wall 300, and the seal ring 13 is provided between the inlet side block 110 and the partition wall 300.
Is sealed by. Here, the entrance block 1
Since both 10 and the partition wall 300 are fixed systems, the sealability by the seal ring 13 is very high. Therefore,
It is impossible for the gasoline leaked into the coupling accommodation hole 111 to leak to the outside through the space between the inlet block 110 and the partition wall 300.

FIG. 5 shows a coupling portion in the second embodiment of the radial piston pump. First mentioned above
The same aspects as those of the embodiment are designated by the same reference numerals, and the description thereof will be omitted. Only different points will be described. Magnet coupling 30A in this radial piston pump,
In 30B, the holder 33 has a cylindrical shape,
The magnet 34 is attached to the outer peripheral surface or the inner peripheral surface of the holder 33. Correspondingly, the partition wall 300 is also formed with the cylindrical protrusion 301. Also in this embodiment, since the space between the inlet side block 110 and the partition wall 300 is reliably sealed by the seal ring 13,
Gasoline never leaks out.

FIG. 6 shows a schematic structure of the coupling portion in the third embodiment of the radial piston pump. In the above-described first and second embodiments, the radial bearing for supporting the pulley shaft 220 is of a double row type, but in the third embodiment, instead of this, two single row radial bearings are used. I'm using it.

More specifically, the entrance side block 110 includes
A partition wall receiving hole 116 is formed outside the coupling housing hole 111, and the cylindrical portion 302 of the hat-shaped partition wall 300 is fitted therein. Collar portion 30 of partition wall 300
3 is the inlet side block 110 and the coupling housing 2
It is sandwiched and fixed between 00 and 00. The magnet coupling 30B on the drive mechanism side is the cylindrical portion 30 of the partition wall 300.
The single-row radial bearing 211 is housed inside the housing 2, and is mounted between the cylindrical portion 302 and the holder 33 of the magnet coupling 30B. The other single row radial bearing 212 is connected to the coupling housing 200.
And the pulley shaft 220.

Also in this third embodiment, since the space between the inlet side block 110 and the partition wall 300 is reliably sealed by the seal ring 13, gasoline will not leak to the outside. The other configurations are basically the same as those of the radial piston pump of the first embodiment, and the same reference numerals are given to the same aspects and the description thereof will be omitted.

FIG. 7 and FIG. 8 are schematic configuration diagrams of the coupling portion in the fourth and fifth embodiments of the radial piston pump, respectively. In these embodiments, the holder of the magnetic coupling on the drive mechanism side is not shown. The structure also serves as a pulley, and there is no coupling housing in the first to third embodiments.

The fourth embodiment will be described in detail with reference to FIG. 7. In the inlet side block 110, a partition wall receiving hole 116 is formed outside the coupling receiving hole 111, and the partition wall 300 is fixed thereto. There is. Entrance side block 11
The holder 33 of the magnet coupling 30B is rotatably supported on the outer side of the end portion of 0 through a single-row radial bearing 213. The partition wall 30 is attached to the holder 33.
The magnet 34 is fixed to a portion of the magnet coupling 30 </ b> A that faces the magnet 34 with 0 interposed therebetween. The holder 33 of the magnet coupling 30B also serves as a pulley, and the rotation of the engine is transmitted to the holder 33 via a belt wound around the pulley.

Also in this fourth embodiment, the seal between the inlet side block 110 and the partition wall 300 is surely sealed by the seal ring 13, so that gasoline will not leak to the outside. Other configurations are basically the same as those of the radial piston pump of the first embodiment.

The radial piston pump of the fifth embodiment shown in FIG. 8 is basically the same as that of the fourth embodiment described above. The major difference is that the number of magnets in the magnet couplings 30A and 30B is larger than that in the fourth embodiment. That is, the magnet coupling 3 of the fourth embodiment.
In 0A, the magnet 34 is attached only to the end surface of the holder 33, but in the case of the magnet coupling 30A of the fifth embodiment, in addition to that, the magnet 35 is attached to the outer peripheral surface of the holder 33. There is. And, corresponding to this, the holder 3 of the magnet coupling 30B
3, the magnet 35 is attached to a portion facing the magnet 35 with the partition wall 300 interposed therebetween.

The present invention is not limited to the above embodiment and various modes can be adopted. For example, the low-viscosity fluid is not limited to gasoline, but may be methanol or alcohol. Further, in the embodiment, the vane pump as the booster pump is incorporated inside the pump housing, but this is not an essential constituent element.

[0046]

As described above, according to the present invention, the end portion of the pump housing is sealed by the partition wall made of a non-magnetic material, and the drive mechanism and the drive shaft are magnet couplings with the partition wall interposed therebetween. Since the rotation is transmitted in a linked manner, the excellent effect of reliably preventing the low-viscosity fluid in the fluid reservoir chamber from leaking to the outside is exhibited.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of a radial piston pump for low viscosity fluid according to the present invention.

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

FIG. 3 is an external perspective view of a spring retainer.

FIG. 4 is an enlarged view of a main part of FIG.

FIG. 5 is a vertical cross-sectional view of a coupling portion in the radial piston pump of the second embodiment.

FIG. 6 is a schematic configuration diagram of a coupling portion in the radial piston pump of the third embodiment.

FIG. 7 is a schematic configuration diagram of a coupling portion in the radial piston pump of the fourth embodiment.

FIG. 8 is a schematic configuration diagram of a coupling portion in the radial piston pump of the fifth embodiment.

[Explanation of symbols]

 20 Drive Shaft 21 Drive Side End 22 Eccentric Cam 30A Magnet Coupling 30B Magnet Coupling 50 Piston 100 Pump Housing 101 Fuel Reservoir (Fluid Reservoir) 200 Pulley Shaft (Drive Mechanism) 300 Partition

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyotaka Ogata 3-13-26, Yasuyukicho, Higashimatsuyama City, Saitama Prefecture Zexel Higashimatsuyama Factory

Claims (1)

[Claims] 1. A drive shaft installed inside a stationary pump housing is rotated by a drive mechanism installed outside the pump housing, and an eccentric cam provided on the drive shaft causes the drive shaft of the eccentric cam to move. A radial piston pump for low-viscosity fluid that reciprocates a plurality of pistons radially arranged around it to increase the pressure of the low-viscosity fluid, forming a part of the inflow passage of the low-viscosity fluid around the eccentric cam in the pump housing. An annular fluid reservoir is provided,
The end of the pump housing that houses the drive-side end of the drive shaft is sealed by a partition wall made of a nonmagnetic material fixed to the end, and the drive-side end of the drive shaft and the drive mechanism are the partition wall. A radial piston pump for a low-viscosity fluid, characterized in that they are connected by a magnetic coupling arranged between them.