JPH0642431A - Swash plate type plunger pump - Google Patents

Abstract

PURPOSE:To realize the maintenance-free state by preventing the deterioration due to the flow-out of lubricating agent and shearing, as for a swash plate type plunger pump for applying a desired pressure to liquid, by reciprocatingly moving a plunger by revolving the swash plate. CONSTITUTION:A swash plate 23 is fixed so that a thrust bearing 23b is aslant for a rotary shaft 19. A plunger 13 having a spring 18 installed at a saucer part 13a is inserted into a cylinder 12. The saucer part 13 is inserted into a tappet 14 inserted into a tappet cylinder 16. The thrust bearing 23b and the tappet 14 are arranged so as to contact each other. A grease case 22 is installed so as to cover the swash plate 23 and the contact part between the tappet 13 and the swash plate 23. The inside of the grease case 22 is filled with grease. Further, the tappet 14 has a collar 14a for preventing the flow-out of the grease.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type plunger pump, and more particularly to a swash plate type plunger pump in which a plunger reciprocated by the rotation of a swash plate obliquely fixed to a rotary shaft applies a desired pressure to a liquid. Plunger pump.

[0002]

2. Description of the Related Art Conventionally, as a pump used for supplying fuel to an internal combustion engine, a swash plate obliquely fixed to a rotary shaft and a plunger reciprocally movable in the longitudinal direction of the rotary shaft have been used. A swash plate type plunger pump for applying a desired pressure to a liquid to be ejected is known (Japanese Patent Laid-Open No. 47-47).
No. 35419).

In the swash plate type plunger pump described in the above publication, the plunger is urged in the swash plate direction so that the swash plate and the plunger slide around the swash plate. Therefore,
When the swash plate rotates obliquely with respect to the rotary shaft as the rotary shaft rotates, the plunger reciprocates in the longitudinal direction of the rotary shaft.

The vicinity of the tip of the plunger is inserted into a liquid passage having a diameter substantially equal to the diameter of the plunger. The tip of this passage communicates with the liquid ejection port, and a liquid supply port is provided in the middle of the passage. This liquid supply port communicates with the liquid passage when the plunger is at the most retracted position,
When the plunger is pushed by the swash plate, it is provided at a position where it is closed by the plunger.

Therefore, when the swash plate rotates and the plunger reciprocates, the liquid to be ejected is supplied from the liquid supply port into the liquid passage and pressed toward the liquid ejection port, and from the liquid ejection port, the plunger is ejected. A liquid having a pressure corresponding to the force pressed by the swash plate is ejected.

Therefore, high-pressure liquid can be ejected by applying a predetermined rotation to the rotary shaft. Also,
In such a pump, a plurality of plungers can be driven by one swash plate, and it is not necessary to provide a drive mechanism for each plunger. Therefore, the size of the pump for obtaining a required flow rate can be reduced. be able to.

[0007]

However, in the above conventional swash plate type plunger pump, a lubricating oil is used as a lubricant for the sliding portion between the swash plate and the plunger, the sliding portion between the plunger and the holding portion of the plunger, and the like. Was used. Therefore, there is a problem in that this lubricating oil passes through the plunger and mixes into the liquid passage.

When the lubricating oil is mixed in the liquid to be sprayed in this way, not only the purity of the liquid deteriorates, but also
There will be insufficient lubricating oil in the pump. Therefore, in the conventional swash plate type plunger pump, it is necessary to replenish the lubricating oil periodically.

Further, in order to suppress the outflow of the lubricant, if a grease having a high viscosity, which is known as a lubricant, is used in place of the lubricant, the grease around the swash plate is severely deteriorated, and the grease is periodically deteriorated. It was necessary to perform maintenance.
That is, according to the above configuration, when grease is filled around the swash plate as a lubricant for the swash plate and the plunger, there is a strong gap between the grease that rotates with the swash plate and the grease that does not rotate due to adhesion to the outer wall. The grease becomes hot as it is sheared. For this reason, the deterioration of the grease used around the swash plate is promoted.

The present invention has been made in view of the above points, and prevents deterioration and outflow of the lubricant due to shearing,
It is an object to provide a maintenance-free swash plate type plunger pump.

[0011]

The deterioration due to shearing of the lubricating oil is caused by the swash plate which is fixed obliquely to the rotation shaft and rotates together with the rotation shaft, and when the swash plate rotates, the swash plate slides against the swash plate. In a swash plate type plunger pump having a tappet that moves and reciprocates and a tappet cylinder that holds the tappet so that the tappet can reciprocate, a grease that is a lubricant for a sliding portion between the swash plate and the tappet is provided inside. However, the problem can be solved by a swash plate type plunger pump having a grease case fixed integrally with the swash plate so as to cover the sliding portion.

[0012] Further, the grease outflow prevents the grease outflow around the portion of the tappet opposite to the side where the swash plate is arranged and which always protrudes from the tappet cylinder. It is solved by providing a preventive means.

[0013]

According to the above construction, the sliding surface between the swash plate and the tappet is always immersed in the grease in the grease case. Further, the grease case rotates together with the grease when the swash plate rotates. Therefore, the grease is not sheared by the rotation, and the temperature of the grease in the steady state is kept low.

Therefore, the friction when the swash plate and the tappet slide is always kept small, and the progress of deterioration of the grease is suppressed.

Further, since grease is used as a lubricant, the grease appropriately flows into the sliding surface between the tappet and the tappet cylinder, and sliding friction between the tappet and the tappet cylinder is generated. It is always kept small and the outflow of the lubricant is suppressed.

The grease outflow preventing means of the tappet is
The grease attached to the sliding surface of the tappet with respect to the tappet cylinder is prevented from spreading to portions other than the sliding surface. Therefore, even if grease is excessively attached to the sliding surface of the tappet with respect to the tappet cylinder, the grease is prevented from flowing out by the grease outflow preventing means and is not mixed in the liquid to be jetted.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing the construction of an embodiment of a swash plate type plunger pump according to the present invention. 2 and 3 are a view taken in the direction of arrow A and a cross-sectional view taken along the line BB in FIG. The configuration of the swash plate type plunger pump of this embodiment will be described below with reference to the drawings.

In the figure, reference numeral 1 denotes a swash plate type plunger pump, which is a pump for increasing the pressure of fuel sucked from a fuel tank of an internal combustion engine (not shown) and supplying it to a fuel injection valve (not shown).

As shown in FIGS. 1 and 2, the cap 2 of the pump of this embodiment is fixed to the case 4 with six fixing bolts 3. A fuel supply port 5 for supplying fuel to the swash plate type plunger pump 1, and a fuel recovery port 6 and a grease recovery port 7 described later are provided inside the position where these fixing bolts 3 are arranged. A fuel injection port 8 for injecting the increased pressure fuel is provided at the center of the cap 2.

As shown in FIG. 1, the fuel injection port 8 communicates with a plurality of fuel passages 9. The swash plate type plunger pump 1 of this embodiment is provided with five fuel passages 9.

These fuel passages 9 are connected to the check valve 1 respectively.
It is communicated with the cylinder 12 provided in the cylinder block 11 via 0. The check valve 10 is composed of a ball valve 10a and a spring 10b that biases the ball valve 10a toward the cylinder 12 with a predetermined spring force.

Therefore, the fuel passage 9 and the cylinder 12 are connected only when the internal pressure of the cylinder 12 is higher than the internal pressure of the fuel passage 9 to the extent that the ball valve 10a is opened against the spring force of the spring 10b. .

Reference numeral 12 is a plunger, and as shown in FIG. 1, about half of its entire length is inserted into the cylinder 12, and the remaining portion is inserted into the tappet 14. The tappet 14 is inserted in a tappet cylinder 16 provided in a tappet cylinder block 15.

A flange-shaped collar 14a corresponding to a grease outflow preventing means is provided at the end of the tappet 14 on the side where the plunger 13 is inserted. Also,
A space corresponding to the collar 14a of the cylinder block 11 is provided with a space for allowing the tappet 14 to reciprocate without interfering with the collar 14a, that is, an escape portion 17. Therefore, the tappet 14 can reciprocate along the tappet cylinder 16.

On the other hand, a spring 18 is arranged between the dish portion 13a of the plunger 13 and the cylinder block 11. The spring 18 acts so as to constantly urge the plate portion 13a toward the tappet 12. Therefore, the tension of the spring 18 also acts on the tappet 14 via the plate portion 13a, and the plunger 13 and the tappet 14 integrally receive the biasing force of the spring 18.

Therefore, by repeating the load for pressing the tappet 14 toward the cylinder block 11 and the unloading of the load, the plunger 13 reciprocates in its longitudinal direction.

Further, reference numeral 19 in the figure denotes a rotary shaft of the swash plate type plunger pump 1, which is held by the case 4 and the tappet cylinder block 15 via an angular bearing 20 and a needle bearing 21. Since the angular bearing 20 is a grease-filled type, it is not necessary to refuel.

The rotary shaft 19 is fixed to a grease case 22 and a swash plate 23 in a space surrounded by the case 4 and the tappet cylinder block 15. The grease case 22 includes a balance plate 22a and a ring 22b, and the space having the swash plate 23 is filled with grease.

On the other hand, the swash plate 23 is composed of a fixed portion 23a which rotates together with the rotary shaft 19 and a thrust bearing 23b. As shown in the figure, the thrust bearing 23 b is held obliquely with respect to the rotary shaft 19.
Therefore, the distance between the thrust bearing 23b and the tappet cylinder block 15 is not uniform, unlike the case where the thrust bearing 23b is held perpendicularly to the rotary shaft 19.

Therefore, the tappet 1 of the pump 1 of this embodiment is
Among the four, those having a short distance between the thrust bearing 23b and the tappet cylinder block 15 are pushed toward the cylinder block 11, and conversely, the thrust bearing 23b and the tappet cylinder block 1 are pushed.
Those located at a long distance from 5 are pushed by the urging force of the spring 18.

Therefore, when the swash plate 23 is rotated through the rotary shaft 19, the tappets 14 reciprocate along the tappet cylinders 16 and the plungers 13 move along the cylinders 12 at a predetermined stroke length. It will reciprocate.

By the way, in such a swash plate type plunger pump, when the tappet 14 is most pressed (at the top dead center), the central axis of the tappet 14 is inclined outward with respect to the central axis of the thrust bearing 23b. On the other hand, when the tappet 14 is at the bottom dead center, the central axis of the tappet 14 is inclined inward with respect to the central axis of the thrust bearing 23b.

Therefore, in the pump of this embodiment, in order to always obtain a uniform contact angle irrespective of this fluctuation, as shown in FIG. 1, the sliding surface 14b of each tappet 14 with the thrust bearing 23b is a spherical surface. The center of rotation of the thrust bearing 23b is offset. The balance plate 22a is provided to offset the offset of the rotation center and make the moment of the rotating system uniform with respect to the rotation center.

As described above, according to the swash plate type plunger pump 1 of this embodiment, by rotating the rotary shaft 19, each plunger 13 can be smoothly reciprocated.

On the other hand, the cylinder 12 of each plunger 13 is provided with a feed hole 24 which communicates with the fuel supply port 5 described above. The feed hole 24 is provided slightly ahead of the tip of the plunger 13 at the bottom dead center.

Since the fuel sucked up by the other pump from the fuel tank is supplied to the fuel supply port 5, when each plunger 13 reaches the position of the bottom dead center, the fuel supplied from the feed hole 24 is supplied to the cylinder. It is filled between the tip of the plunger 13 in 12 and the check valve 10.

Next, when the swash plate 23 rotates and the plunger 13 starts moving toward the top dead center, the feed hole 24
Is blocked by the plunger 13 itself, and pressure is applied to the fuel trapped in the cylinder 12. This pressure is the check valve 1
When the pressure becomes sufficient to open 0, fuel flows out from the fuel passage 9 toward the fuel injection port 8.

At this time, the high-pressure fuel flowing out from the other fuel passages does not flow back into the cylinder 12 due to the action of the check valve 10 provided in each fuel passage.

A circumferential groove 25 is provided at the position where the feed hole 24 of the cylinder 12 is provided.
The inside of the circumferential groove 25 is always kept at the same pressure as the pressure of the fuel supplied from the fuel supply port 5. Therefore, when the plunger 13 pressurizes the fuel, the high-pressure fuel that flows backward from the gap between the cylinder 12 and the plunger 13 is captured here, and the pressure of the fuel pressurized by the plunger 13 is It is not transmitted behind 25.

A leak hole 26 is provided behind the circumferential groove 25 of the cylinder 12. This leak hole 26
Is connected to the fuel recovery port 6 and is always maintained near atmospheric pressure. Therefore, when the fuel supplied from the feed hole 24 is transmitted between the cylinder 12 and the plunger 13, the fuel is captured here and returned to the fuel recovery port 6, and the fuel is supplied to the rear of the leak hole 26. The pressure of the fuel supplied from the supply port 5 is not transmitted.

As described above, in the swash plate type plunger pump 1 of this embodiment, the fuel that has passed through the space between the cylinder 12 and the plunger 13 is double captured. Therefore, a perfect fuel seal can be realized without using a sealing material such as an O-ring.

Next, the grease case 22 and the tappet 14 which are essential parts of the swash plate type plunger pump 1 of this embodiment.
The effect of the brim 14a will be described.

As described above, the grease case 22 is filled with grease to serve as a lubricant for the sliding portion or the rotating portion of the swash plate 23, the thrust bearing 23b, the tappets 14 and the like.

As described above, according to the swash plate type plunger pump 1, the grease is contained in the grease case 22 and is not in contact with the case 4. For this reason, in the conventional swash plate type plunger pump, when the swash plate rotates, shear occurs between the grease that rotates with the swash plate and the grease that does not rotate because it adheres to the case and does not rotate. The plate plunger pump does not shear the grease.

Therefore, the temperature of the grease is kept lower than that of the conventional pump, and the grease is prevented from deterioration.

Further, when the tappet 14 reciprocates with the grease filled in the grease case 22, the grease also flows into the gap between the tappet 14 and the tappet cylinder 16 and slides between the tappet 14 and the tappet cylinder 16. The grease spreads over the entire side surface of the tappet 14, which is the moving surface.

Here, when the tappet 14 in which the grease spreads over the entire side surface moves from the top dead center to the bottom dead center, the tappet cylinder block 15 is at the top dead center.
The grease attached to the protruding portion is scraped off at the edge of the tappet cylinder block 15 and attached to the end portion of the tappet 14. Therefore, when the tappet 14 continuously reciprocates, grease gradually accumulates at the end of the tappet 14.

In the pump 1 of this embodiment, the tappet 1
4 has a collar 14a at the end of the sliding surface. For this reason, the grease accumulated at the end of the tappet 14 is
It flows downward on the circumference of the tappet 14 along a and drops into the escape portion 17.

Therefore, the grease does not flow into the tappet 14 and does not adhere to the plunger 13. Therefore, the grease does not flow out between the plunger 13 and the cylinder 12, and the mixing of the fuel and the grease is prevented.

FIG. 3, which is a sectional view taken along the line BB in FIG. 1, shows the structure of a grease recovery groove or the like provided for recovering grease from the escape portion 17 provided for each plunger 13.

In the figure, reference numeral 25 is a grease recovery groove, which communicates with the lower side of each escape portion 17. For this reason,
The grease dropped from each tappet 14 to the escape portion 17 is always guided to the grease recovery groove 27, and the other escape portion 17
The grease flowing out from the grease recovery groove 27 does not flow into the escape portion 17.

Each grease recovery groove 27 communicates with a grease recovery passage 28 provided on the outer periphery of each escape portion 17. Further, the grease recovery passage 28 is connected to a grease recovery hole 29 which is in communication with the grease recovery port 7 in the vicinity of the lowermost portion thereof. For this reason, the grease dropped from each tappet 14 will not be removed by the grease recovery groove 2
7, through the grease recovery passageway 28 to reach the grease recovery hole 29, and then the grease recovery port 7 recovers the grease.

In the above embodiment, the "collar" is used as the grease outflow preventing means, but the invention is not limited to this, and it is possible to prevent the outflow of the grease flowing out between the tappet and the tappet cylinder. Any configuration will do.

[0054]

As described above, according to the first aspect of the invention, the grease that is the lubricant for the sliding portion between the swash plate and the tappet is held in the grease case and rotates together with the swash plate. For this reason, when the swash plate rotates like the swash plate type plunger pump having the conventional configuration, the grease is not sheared and the temperature rise is suppressed.

Therefore, the grease is kept at a low temperature and its deterioration is suppressed as compared with the case of the conventional structure, so that it is not necessary to maintain the grease for a long period of time. Further, since grease is used as the lubricant instead of the lubricating oil, the consumption of the lubricant is small, and the swash plate type plunger pump can be maintenance-free.

According to the second aspect of the invention, the grease that flows into the gap between the tappet and the tappet cylinder and acts as a lubricant between them does not spread before the brim of the tappet. For this reason, this grease does not adhere to the plunger inserted in the tappet, and does not flow out between the plunger and the cylinder to be mixed with the fuel. Therefore, according to the swash plate type plunger pump of the present invention, it is possible to always maintain the purity of the injected fuel to be normal.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of a swash plate type plunger pump according to the present invention.

FIG. 2 is a side view of the swash plate type plunger pump of the present embodiment.

FIG. 3 is a cross-sectional view of a swash plate type plunger pump of this embodiment.

[Explanation of symbols]

 1 Swash plate type plunger pump 4 Case 12 Cylinder 13 Plunger 14 Tappet 14a Collar 16 Tappet cylinder 17 Relief part 19 Rotating shaft 22 Grease case 22a Balance plate 22b Ring 23 Swash plate 23a Fixed part 23b Thrust bearing

Claims (2)

[Claims] 1. A swash plate that is obliquely fixed to a rotating shaft and rotates together with the rotating shaft, a tappet that slides on the swash plate when the swash plate rotates, and a reciprocating motion of the tappet. In a swash plate type plunger pump having a tappet cylinder that holds the swash plate, a grease that is a lubricant for a sliding portion between the swash plate and the tappet is provided inside, and the swash plate is provided so as to cover the sliding portion. A swash plate type plunger pump having a grease case fixed integrally. 2. A swash plate that is obliquely fixed to a rotation shaft and rotates together with the rotation shaft, a tappet that reciprocates by sliding on the swash plate when the swash plate rotates, and a reciprocating motion of the tappet. In a swash plate type plunger pump having a tappet cylinder that is capable of being held, grease that is a lubricant between the tappet and the tappet cylinder, and the tappet, on the side opposite to the side on which the swash plate is disposed,
A swash plate type plunger pump, comprising: a grease outflow prevention means that is provided around a portion that always protrudes from the tappet cylinder and that prevents the grease from flowing out.