JPH09250447A - Fluid supply pump and fuel supply pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce slide resistance and improve seizure resistance by providing a pintle valve on the opposite inclined shaft side of a cylinder and providing a balance groove parallel to a pintle valve groove on the periphery of the pintle valve in a fluid supply pump provided with a swash plate and reciprocating plural pintles. SOLUTION: In a swash plate type fuel supply pump for supplying low- viscosity fuel for direct fuel injection in an engine cylinder, an inlet port 16 of a rear cover 14 communicates with a crank chamber 20 in a housing 12 and communicates with a pintle valve 22 coaxial with the rotary shaft of the cylinder. The pintle valve 22 has a first intake pressure groove 24, a communicating path 22a to this intake pressure groove 24, a first delivery pressure groove 30, and a communicating path 60 from this delivery pressure groove 30 to the delivery port. This pintle valve 22 is also provided with a balance groove consisting of a second intake pressure groove 32 to communicate with the intake pressure groove 24 and the delivery pressure groove 30, and a second delivery pressure groove 34, thereby the radial force from each groove due to the intake and delivery pressures is balanced and the generation of the radial force to the cylinder is restricted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a fuel supply pump for a gasoline automobile, which supplies a low viscosity fuel for direct fuel injection in an engine cylinder.

[0002]

2. Description of the Related Art As a fuel supply pump (fuel injection pump) for supplying fuel for fuel injection, a diesel light oil fuel injection pump has already been put into practical use, but the viscosity of light oil supplied by this fuel supply pump is high. Is 5 times as much as gasoline and is not a fuel supply pump that supplies low viscosity fuel.

On the other hand, as a low-viscosity gasoline-compatible fuel supply pump, as described in Japanese Patent Application Laid-Open No. 4-209981, the drive section and the piston reciprocating section are filled with high-viscosity oil for lubrication. A two-fluid type that performs piston suction and discharge by suppressing the amount of piston leakage and further installing a bellows between the piston and cylinder, partitioning oil and gasoline by the bellows and expanding and contracting the bellows by the reciprocating motion of the piston. A pump is proposed.

As a hydraulic pump, US Pat.
As described in the specification and drawings of No. 129797, an oblique shaft pump having a constant velocity joint and a piston ring has been proposed.

[0005]

However, the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 4-209981 is
Since it has a two-fluid structure for low-viscosity gasoline, it requires a bellows and a diaphragm, and structurally has the following problems.

[0006] 1. There is a limit to the strength of the bellows, and it was difficult to directly drive the bellows itself. (In order to suppress the bellows strength and obtain a specified stroke, it is necessary to lengthen the bellows and increase the number of peaks, which is a space problem.) Similarly, in order to obtain the discharge amount with respect to the diaphragm strength, it is necessary to increase the diameter of the diaphragm, which also causes a problem of pump space.

[0007] 3. If there is air bubbles in the oil in the bellows or the diaphragm, there is a problem that the bellows itself cannot be provided with a stroke equivalent to the required gasoline discharge amount even if the plunger makes a specified stroke movement, resulting in poor performance. (Even if the bubbles in the oil were removed in the initial state, there was a problem that bubbles were generated due to the oil temperature rising due to the heat generation of the sliding portion due to the pump operation.) Further, the specification and drawings of the above-mentioned US Pat. No. 5,129,977. Since the technique described in (1) is designed on the assumption of oil viscosity and seizure resistance, there are the following problems in dealing with one fluid for gasoline.

[0008] 1. Supporting the thrust force of the reaction force generated by the hydraulic pressure with the valve plate valve may cause seizure.

[0009] 2. Further, it is necessary to suppress the sliding resistance generated in the drive section.

3. A piston ring is required due to the problem of piston sealability, and in the structure that directly supports the piston side force between the piston and the cylinder bore,
There is a problem of seizure of the piston itself, and in the case of the oblique shaft type, it was necessary to have a cylinder rotating structure using a constant velocity joint.

An object of the present invention is to solve the above problems.
An object of the present invention is to provide a fluid supply pump and a fuel supply pump having a one-fluid structure that can use a low-viscosity fluid as a working fluid.

[0012]

In order to achieve the above object, the present invention provides an oblique shaft which is a rotating shaft, and a joint which connects the oblique shaft and a cylinder and transmits the rotation of the oblique shaft to the cylinder.
A cylinder that reciprocates a plurality of pistons by rotation; and a plurality of pistons that are provided between the oblique shaft and the cylinder and that reciprocate in the axial direction of the cylinder when the oblique shaft and the cylinder rotate. Comprised of a drive unit having, by the reciprocating movement of the piston,
A predetermined volume of fluid is sucked from outside the pump through the cylinder in the pump and discharged to the outside of the pump,
In a fluid supply pump that supplies to an external device, a pintle valve that controls suction and discharge of the fluid of the predetermined volume is provided on the same central axis as the rotation central axis of the cylinder and on the side opposite to the oblique axis of the cylinder, A pintle valve groove that communicates with the cylinder is provided on the outer circumference of the pintle valve, and a balance that communicates with the pintle valve groove is separated from the pintle valve groove by a predetermined distance to the oblique axis side and is parallel to the pintle valve groove. A feature is that a groove is provided.

Another feature of the present invention is that an oblique shaft serving as a rotary shaft, a joint that connects the oblique shaft and a cylinder to transmit the rotation of the oblique shaft to the cylinder, and reciprocates a plurality of pistons by the rotation. The piston includes a cylinder and a drive unit having a plurality of pistons provided between the oblique shaft and the cylinder and reciprocating in the axial direction of the cylinder when the oblique shaft and the cylinder rotate. By reciprocating, a fuel fluid of a predetermined volume is sucked from outside the pump through the cylinder inside the pump and discharged to the outside of the pump, and is supplied to engine equipment. A pintle valve for controlling suction and discharge of the fuel fluid of the predetermined volume is provided on the same central axis as the rotation central axis and on the side opposite to the oblique axis of the cylinder. A pintle valve groove that communicates with the cylinder is provided on the outer periphery of the valve, and a balance groove that communicates with the pintle valve groove and is separated from the pintle valve groove by a predetermined distance toward the oblique axis and is parallel to the pintle valve groove is provided. It is to provide.

According to the present invention, a pintle valve for controlling suction and discharge of a fluid having a predetermined volume is provided on the same central axis as the rotation center axis of the cylinder and on the side opposite to the oblique axis of the cylinder. A pintle valve groove is provided on the outer circumference of the pintle valve so as to communicate with the cylinder. At the same time, the balance groove is provided at a predetermined distance from the pintle valve groove to the oblique axis side and in parallel with the pintle valve groove so as to communicate with the pintle valve groove.

As a result, the pump structure can be a one-fluid structure, so that the pump can be downsized.

Further, by constructing the crank chamber including the drive unit so as to form a part of the working fluid suction passage, it is possible to prevent the sliding heat of the drive unit by the working fluid and prevent seizure. Further, by configuring the passages communicating with the respective sliding portions and the working fluid filled portion of the crank chamber and the sliding portion and the working fluid filled portion of the crank chamber to be in direct contact,
The seizure can be prevented more effectively.

Further, sliding resistance is reduced by using a pintle valve having a balance groove in the valve structure, using a rolling bearing as the bearing, and adopting a cylinder rotating structure using a constant velocity joint as the pump structure. be able to.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A fuel supply pump according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of the entire structure of a fuel supply pump according to an embodiment of the present invention. The drive shaft is composed of a slant shaft 1, the cylinder 3 is connected by a constant velocity joint 5, and a piston 7 reciprocates so as to suck and discharge a required capacity as a pump. In this embodiment, the number of pistons 7 is 6
Although it is composed of a book, any number may be used as long as it is three or more.
The stroke amount of the piston 7 is defined by the tilt angle with respect to the rotation axis of the oblique shaft 1 and the cylinder 3. One end of the piston 7 has a spherical surface portion, and this spherical surface portion is fitted to the spherical surface portion provided on the oblique shaft 1.

The reaction force of the hydraulic pressure generated in the pump chamber constituted by the cylinder bore 3a and the piston 7 is transmitted to the oblique shaft 1 via the piston support 52 and the thrust rolling bearing 9a. The hydraulic reaction force transmitted to the swash shaft 1 is transmitted to the swash plate 10 of the fixing member and supported by the housing 12.

On the other hand, the hydraulic reaction force acting on the cylinder 3 side is transmitted to the cylinder 3, and the cylinder 3 and the rear cover 14 are connected.
The structure is supported by a thrust rolling bearing 9b provided between and. The hydraulic reaction force thus supported is applied to the housing 12 and the rear cover 14 by the four bolts 5.
By fixing at 0, the power of the pump is balanced.

As described above, the sliding portion of the driving portion has a structure in which the rolling bearing is utilized as much as possible and the load itself can be reduced. In addition, since it is premised on an axial pump, an oblique shaft pump that can reduce the reaction force of the driving torque is selected, and at the same time, in order to support the thrust force of the hydraulic reaction force that has the greatest influence on the generated load, A structure is provided in which rolling bearings are provided for the thrust support of the oblique shaft and the thrust support of the cylinder.

Further, the piston support 52 is the cylinder 3
In order to prevent the cylinder 3 from moving to the side, a spring 53 and a center tooth 51 are provided at the center of the cylinder 3 so that the piston support 52 is always pushed toward the oblique shaft 1 side.

FIG. 2 shows a II cross section of FIG. The rear cover 14 is provided with a suction port 16 and a discharge port 18, and the suction port 16 is formed in the crank chamber 2 of the housing 12.
0 through a passage 4 and further extends in the center of the cylinder 3 perpendicularly to the thrust bearing surface of the rear cover 14 and to a pintle valve 22 coaxial with the rotation axis of the cylinder 3.

FIG. 3 shows a II-II cross section of FIG. The pintle valve 22 is provided with a first suction pressure groove 24, a communication passage 22a to the first suction pressure groove 24, and a communication from the first discharge pressure groove 30 to the discharge port 18 of the rear cover 14. A passage 60 is provided.

FIG. 4 shows a section taken along line III-III in FIG. It shows a structure in which the cylinder 3 is provided with a communication passage 25 from the crank chamber 20 to the communication passage 22a for sucking the working fluid into the cylinder bore 3a. This structure of providing the communication passage is for the purpose of absorbing the heat generated in the sliding portion in the crank chamber 20 with the working fluid and discharging the heat to the outside of the pump.

Therefore, it is important to communicate each sliding portion with the crank chamber 20, and FIG. 5 shows an example of a communication passage between the sliding portion of the oblique shaft 1 and the crank chamber 20. The swash plate 10 is provided with a communication passage 10a to a shaft seal 26 provided to prevent the working fluid in the crank chamber 20 from leaking from the swash shaft 1.
Further, the shaft seal 26 and the crank chamber 20 are communicated with each other through the rollers of the radial roller bearings 28a and 28b and the thrust rolling bearing 9a.

By this path, the working fluid is ejected to the inner wall surface side of the housing 12 in the crank chamber 20 by the centrifugal force caused by the rotation of the thrust bearing 9a, and the inner wall surface side pressure becomes high, and this pressure is high. By opening the communication passage 10a in the part, a working fluid sliding portion circulation system shown by a solid arrow is established. Here, when the inclination angle of the oblique shaft 1 is as small as 10 ° or less, the sliding bearing can be used without using the rolling bearing as the radial bearing. In this case, the effect of circulating the working fluid in the sliding portion can be expected as in the case of using the radial bearing.

By the same centrifugal force as above, the working fluid also lubricates the sliding portion between the ball outer diameter portion 5a of the constant velocity joint 5 and the shaft portion 5b, as indicated by the broken line arrow.

FIG. 6 shows an enlarged configuration of the pintle valve 22 of FIG. As shown in FIG. 6, on the outer circumference of the pintle valve 22, a groove for sucking the working fluid into the pump chamber constituted by the cylinder bore 3a and the piston 7 and a groove for discharging the working fluid from the pump chamber are provided. 7 and 8 show the cross-sectional shape of the groove.

FIG. 7 shows a cross section taken along the line AA of FIG. A-A
A first suction pressure groove 24 and a first discharge pressure groove 30 which are pintle valve grooves are provided in the cross section. The first suction pressure groove 24 is formed from a start point to an end point, and the first discharge pressure groove 30 is formed from a start point to an end point.

FIG. 8 shows a BB cross section of FIG. The second suction pressure groove 32 of the same pressure communicating with the first suction pressure groove 24 and the first suction pressure groove 32 and the first suction pressure groove 24 are parallel to the cross section AA of FIG. A balance groove composed of a second discharge pressure groove 34 having the same pressure and communicating with the discharge pressure groove 30 is provided. The second suction pressure groove 32 is composed of the start point (3) to the end point (4), and the second discharge pressure groove 34 is formed from the start point (1) to the end point (2).
It is composed of

A radial force Fs1 which is a product of the linear distance Ls1 connecting the starting point and the ending point of the first suction pressure groove 24, the groove width Bs1 and the suction pressure, and the starting point to the ending point of the first discharge pressure groove 30. Distance Ld1 and groove width Bd
1 is set by the radial force Fd1 which is the product of the discharge pressure and the linear distance connecting the start point (3) to the end point (4) of the second suction pressure groove 32. The structure is designed to balance the radial force from the groove and suppress the generation of radial force to the cylinder.

Similarly, the straight line distance connecting the start point and the end point of the first discharge pressure groove 30 and the straight line distance connecting the start point (1) and the end point (2) of the second discharge pressure groove 34 are With the same setting, the radial force from each groove due to the discharge pressure is balanced to suppress the generation of radial force to the cylinder.

Further, the first suction pressure groove 24 in the BB cross section of the pintle valve 22 and the side of the first discharge pressure groove 30 opposite to the oblique axis, and the second suction pressure 32 in the AA cross section. Second discharge pressure groove 3
4 at the oblique axis side, and at the same time, the groove of the BB section (the first suction pressure groove
4. A seal for sealing the circumferential clearance between the cylinder 3 and the first discharge pressure groove 30) and the AA cross-section groove (second suction pressure groove 32, second discharge pressure groove 34). The ring 35 is provided to reduce the amount of leakage at the outer periphery of the pintle valve.

FIG. 9 shows the relationship of forces acting on the cylinder around the pintle valve. The force Fp applied in the radial direction is displaced by a distance L in the axial direction to provide a balance groove, and a moment M2 (Fp × L) is generated by Fp. This moment M2 is a piston hydraulic pressure resultant force generated in each cylinder bore 3a. The moment M1 (F1 × R) due to Fl is canceled and the reaction force Ft acting on the thrust bearing becomes smaller than F1 by Fp × L / R, and the sliding resistance can be reduced accordingly. it can.

That is, since the piston hydraulic force (thrust force) acts on the eccentric position on the discharge side from the cylinder axis, the moment force M1 acts on the axis connecting the piston top dead center and the piston top dead center of the cylinder. To do. A balance groove for balancing the hydraulic pressures acting on the pintle valve and the pintle valve groove is provided on the outer circumference of the pintle valve so as to oppose this moment force M1.

The balance groove has a groove projection area equal to that of the pintle valve groove so as to balance the radial force between the central portions of the cylinders and has a pressure relationship against the pintle valve groove. It is located at a distance. When hydraulic pressure is applied to the balance groove, a moment M2 in a direction opposite to the moment force M1 is generated, and the piston hydraulic force (thrust force) can be reduced by an amount corresponding to the moment M2.

As a result, the action of the piston hydraulic force (thrust force) with the rear cover on the side opposite to the drive shaft of the cylinder due to the hydraulic reaction force can be reduced.

Further, in this embodiment, since the oblique shaft 1 and the cylinder 3 are connected by the constant velocity joint 5, the vibration noise of the pump can be suppressed to a low level.

[0041]

According to the present invention, since the pump structure is a one-fluid structure, the bellows, the diaphragm and the like are unnecessary, and the pump can be made compact. Further, by making the crank chamber including the drive part a part of the working fluid suction passage, the working fluid removes the sliding heat of the drive part, and seizure can be prevented.

Further, by using a pintle valve provided with a balance groove for the valve structure, using a rolling bearing for the bearing, and adopting a cylinder rotating structure using a constant velocity joint as the pump structure, sliding resistance is reduced. It is possible to further improve the seizure resistance.

[Brief description of drawings]

FIG. 1 is a sectional view of an entire structure of a fuel supply pump according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a suction / discharge port of a working fluid in a II cross section of FIG.

FIG. 3 is an explanatory view of a suction / discharge passage of a working fluid to a cylinder in a II-II cross section of FIG. 1.

4 is an explanatory view of a cylinder suction passage from a crank chamber in a III-III cross section of FIG.

FIG. 5 is an explanatory diagram of a sliding portion lubrication path.

FIG. 6 is an enlarged configuration diagram of the pintle valve of FIG. 1.

7 is a cross-sectional view taken along the line AA of FIG.

8 is a sectional view taken along line BB of FIG. It is explanatory drawing of the balance of the force around a pintle valve.

FIG. 9 is an explanatory diagram of a force relationship that acts on a cylinder around a pintle valve.

[Explanation of symbols]

1 ... Oblique shaft, 3 ... Cylinder, 3a ... Cylinder bore, 4 ... Passage, 5 ... Constant velocity joint, 6 ... Discharge communication passage, 7 ... Piston, 9
a, 9b ... Thrust bearing, 10 ... Swash plate, 12 ... Housing, 14 ... Rear cover, 16 ... Suction port, 18 ... Discharge port, 2
0 ... Crank chamber, 22 ... Pintle valve, 22a ... Communication passage,
24 ... First suction pressure groove, 26 ... Shaft seal, 28
a, 28b ... radial bearing, 30 ... first discharge pressure groove, 3
2 ... 2nd suction pressure groove, 34 ... 2 discharge pressure groove, 35 ... Sea
Luling, 50 ... Bolt, 51 ... Center sea, 52 ...
Piston support, 53 ... Spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takanobu Kanamaru 2520 Takaba, Hitachinaka City, Ibaraki Prefecture Hitachi Ltd. Automotive Equipment Division, Hitachi Ltd. (72) Yukio Takahashi 2520 Takaba, Hitachinaka City, Ibaraki Prefecture Hitachi, Ltd. Automotive Equipment Division

Claims (9)

[Claims] Claims: 1. An oblique shaft serving as a rotating shaft, a joint for connecting the oblique shaft and a cylinder to transmit the rotation of the oblique shaft to the cylinder, and a cylinder for reciprocating a plurality of pistons by the rotation.
The drive unit is provided between the oblique shaft and the cylinder and has a plurality of pistons that reciprocate in the axial direction of the cylinder when the oblique shaft and the cylinder rotate, and the piston reciprocates. By doing so, in a fluid supply pump that sucks a predetermined volume of fluid from outside the pump through the cylinder in the pump and discharges the fluid to the outside of the pump, A pintle valve that controls suction and discharge of the fluid of the predetermined volume is provided on the same central axis and on the side opposite to the oblique axis of the cylinder, and a pintle valve groove that communicates with the cylinder is provided on the outer periphery of the pintle valve. At the same time, a balance groove communicating with the pintle valve groove and separated from the pintle valve groove by a predetermined distance toward the oblique axis and parallel to the pintle valve groove may be provided. Characteristic fluid supply pump. 2. The pintle valve groove according to claim 1,
It is composed of a first suction pressure groove for sucking the predetermined volume of fluid through the cylinder and a first discharge pressure groove for discharging the fluid.
The balance groove communicates with the first suction pressure groove and a second suction pressure groove that generates a pressure that balances with a pressure generated in the first suction pressure groove; and the first discharge pressure groove. A fluid supply pump comprising: the second discharge pressure groove communicating with the groove and generating a pressure that balances with the pressure generated in the first discharge pressure groove. 3. The fluid supply pump according to claim 1, wherein the sliding portion of the drive portion is directly cooled by the fluid flowing in the pump. 4. An oblique shaft serving as a rotary shaft, a joint for connecting the oblique shaft and a cylinder to transmit the rotation of the oblique shaft to the cylinder, and a cylinder for reciprocating a plurality of pistons by the rotation.
The drive unit is provided between the oblique shaft and the cylinder and has a plurality of pistons that reciprocate in the axial direction of the cylinder when the oblique shaft and the cylinder rotate, and the piston reciprocates. By so doing, a predetermined amount of fuel fluid is sucked from outside the pump via the cylinder in the pump and discharged to the outside of the pump,
In a fuel supply pump that supplies engine equipment, a pintle valve that controls intake and discharge of the fuel fluid of a predetermined volume is provided on the same central axis as the rotation center axis of the cylinder and on the side opposite to the oblique axis of the cylinder. A pintle valve groove communicating with the cylinder is provided on the outer periphery of the pintle valve, and the pintle valve groove is communicated with the pintle valve groove at a predetermined distance from the pintle valve groove to the oblique shaft side and parallel to the pintle valve groove. A fuel supply pump having a balance groove. 5. The pintle valve groove according to claim 4,
It comprises a first suction pressure groove for sucking the predetermined amount of fuel fluid through the cylinder and a first discharge pressure groove for discharging the fuel fluid, and the balance groove communicates with the first suction pressure groove. A second suction pressure groove for generating a pressure that balances with the pressure generated in the first suction pressure groove, and a pressure communicating with the first discharge pressure groove and generated in the first discharge pressure groove. And a second discharge pressure groove for generating a pressure that balances with the fuel supply pump. 6. The fuel supply pump according to claim 4, wherein the sliding portion of the drive portion is directly cooled by the fuel fluid flowing in the pump. 7. The fuel supply pump according to claim 4, wherein a thrust rolling bearing is provided on the side opposite to the oblique axis of the cylinder. 8. The fuel supply pump according to claim 4, wherein the reaction force due to the pressure generated in the cylinder bore of the cylinder is supported by a vertical surface integrally formed with the pintle valve. 9. The outer peripheral surface of the pintle valve according to claim 4, wherein the pintle valve groove has an anti-oblique axis side, an oblique axis side of the balance groove, and between the pintle valve groove and the balance groove. A fuel supply pump comprising a seal ring for sealing a circumferential clearance between the cylinder and the cylinder.