JPH07269444A - High pressure fuel pump - Google Patents

Abstract

PURPOSE:To dispense with exclusive covering members for covering openings, and improve the workability of assembling and removal of a cam shaft. CONSTITUTION:A plunger driving cam shaft 25 is inserted-arranged in a pump housing 26, and an opening 27 into which the cam shaft 2 can be axially inserted, is formed at the part on the opposite side of the cam shaft driving force input side in the pump housing 26. A valve body 58a of an oil pump 58 for feeding lubricating oil to the plunger sliding part, is fitted to the end part on the opening 27 side of the cam shaft 25, and the oil pump 58 is loaded to the pump housing 26 so that it can close the opening 27 and can be fitted to and removed from the pump housing 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high pressure fuel pump used in a fuel supply system for a fuel injection type internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as a high-pressure fuel pump used in a fuel supply system for a fuel injection type internal combustion engine, for example, Japanese Patent Laid-Open No. 5-58200 is known.
As described in Japanese Patent Publication No. 288098, a cam shaft for driving a plunger forward and backward is inserted and arranged in a pump housing, and left and right ends of the cam shaft are supported by a pump housing via ball bearings. There is one in which a cam shaft driving force transmitting means such as a gear is attached to an outward protruding portion of the shaft. Further, in this conventional device, an opening is formed in the pump housing for extracting the cam shaft to the side opposite to the driving force input side, and a lid member for opening and closing the opening is attached.

[0003]

By the way, in the above-mentioned conventional high-pressure fuel pump, it is possible to assemble and dismount the cam shaft in the pump housing by utilizing the opening formed in the pump housing. A dedicated lid member for closing is required. Further, since the opening side portion of the cam shaft is supported by the pump housing via the ball bearing, the size of the opening is restricted by the diameter of the ball bearing, which makes it difficult to remove the cam shaft. There is.

The present invention has been made in view of the above-mentioned conventional problems, and a dedicated lid member for closing the opening can be eliminated, and the size of the opening is restricted by the size of the bearing. It is an object of the present invention to provide a high-pressure fuel pump that does not have a camshaft and can improve the workability of assembling and removing the camshaft.

[0005]

According to a first aspect of the present invention, in a high-pressure fuel pump used in a fuel supply system for a fuel injection type internal combustion engine, a cam shaft for driving a plunger is inserted in the pump housing, and the pump housing is provided. Of the oil pump which forms an opening into which the cam shaft can be inserted in the axial direction at a portion opposite to the cam shaft driving force input side, and which supplies lubricating oil to the plunger sliding portion at the opening side end portion of the cam shaft. It is characterized in that a valve body is mounted and a casing of the oil pump is detachably mounted on the pump housing so as to be able to close the opening.

According to a second aspect of the present invention, in the first aspect, the casing of the oil pump includes a pump plate that closes the opening of the pump housing and a plate cover attached to the pump plate. It is characterized in that at least a part of the oil passage is formed at the boundary between the pump plate and the pump plate.

According to a third aspect of the present invention, in the second aspect, the pump plate supports a bearing that axially supports the opening side portion of the cam shaft, and the fourth aspect of the invention is that Item 3 is characterized in that the pump housing supports a bearing that axially supports the driving force input side portion of the cam shaft.

[0008]

According to the high pressure fuel pump of the first aspect of the present invention, when the camshaft is mounted in the pump housing,
When the cam shaft is inserted through the opening and an oil pump is attached, the opening is closed. When removing the camshaft from the pump housing, the power transmission member mounted on the input side of the camshaft is removed, the oil pump is removed from the pump housing, and the camshaft is pulled outward from the opening.

As described above, according to the present invention, since the oil pump is arranged so as to close the opening for assembling and removing the cam shaft, the oil pump also serves as the lid member, so that the dedicated lid member can be eliminated. .

According to the invention of claim 2, the casing of the oil pump is constituted by a pump plate for closing the opening of the pump housing and a plate cover attached to the pump plate, and the plate cover and the pump. Since the oil passage is formed at the boundary with the plate, the lubricating oil passage can be secured with a simple structure.

According to the third aspect of the present invention, the bearing supporting the opening side portion of the cam shaft is supported by the pump plate. Therefore, when setting the size of the opening, the opening is set to the diameter of the bearing. There is no restriction on setting the aperture size such as matching. Therefore, the above-mentioned opening can be enlarged, and workability in inserting or removing the cam shaft into or from the opening is improved.

Further, in the invention of claim 4, since the bearing for the driving force input side is supported by the pump housing, the structure can be simplified without impairing the workability of assembling and removing the cam shaft.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 11 are views for explaining a fuel supply device according to an embodiment of the present invention, FIG. 1 is a schematic partial cross-sectional view showing the entire structure of the fuel supply device, and FIG. 2 is the fuel supply device. Of the high pressure fuel pump of FIG. 3, FIG. 3 is an enlarged cross sectional front view of the barrel of the high pressure fuel pump, FIG. 4 is a left side view of the fuel pump, and FIG.
FIG. 6 is a right side view of the fuel pump, FIG. 7 is a right side view of a part of the fuel pump, FIG. 8 is a plan view of the fuel pump, and FIG. 9 is a barrel attached to the fuel pump. Is a partial plan view, FIG. 10 is a sectional side view of a low-pressure regulator adopted in the fuel supply device, and FIG. 11 is an enlarged view of a seal member used in the fuel pump.

In these figures, reference numeral 1 denotes a fuel supply device for supplying fuel to the combustion chamber 6 of the engine 5. The fuel supply device 1 includes a fuel tank 7 and the fuel tank 7
A low-pressure supply pump 9 which is installed inside and discharges the fuel in the tank 7 to the filter 8, a high-pressure fuel pump 10 to which fuel is supplied from the low-pressure supply pump 9 through the filter 8, and the fuel pump 10 It is provided with a first pressure accumulation chamber 11 in which the high-pressure fuel discharged from the engine is temporarily stored, and an injector 12 attached to the engine 5 and supplied with the high-pressure fuel in the first pressure accumulation chamber 11.

The high pressure fuel pump 10 is provided with a low pressure regulator 14 to which the fuel from the low pressure supply pump 9 is supplied via a fuel passage 13. The low-pressure regulator 14 is configured such that when the pressure of the fuel supplied from the low-pressure supply pump 9 in the regulator 14 becomes a predetermined value or more, a part of the supplied fuel is passed through a fuel passage 16 to a fuel tank. It is configured to return to the 7 side.

As shown in FIG. 10, the low-pressure regulator 14 has a diaphragm 71 which forms a regulator pressure accumulating chamber (second pressure accumulating chamber) 72 and an atmosphere chamber 75 in a case formed by a lower case 69 and an upper case 73. The regulator pressure accumulating chamber 72 is communicated with the suction side of the high-pressure fuel pump 10 through the introduction holes 70a and 70b of the mounting bolt 70 fixed to the lower case 69, and the atmosphere chamber 75 is defined.
Is communicated with the atmosphere through a communication hole 73a provided in the upper case 73. Reference numeral 77 is a fixing nut for fixing the low pressure regulator 14 to the cylinder body 24, and 76 is a sealing material.

The valve body 8 is provided at the center of the diaphragm 71.
1 is fixed, and the valve body 81 has the mounting bolt 70
The valve seat 70c formed on the protruding portion in the case can be opened and closed. The valve element 81 is biased in the closing direction by a coil spring 74 interposed between the upper case 73 and the spring receiver 82. The relief passage 70d communicating with the valve seat 70c is connected to the fuel tank 7 via the fuel passage 16.

A first fuel pressure sensor 17 for measuring the pressure inside the pressure accumulation chamber 11 is attached to the first pressure accumulation chamber 11, and the first fuel pressure sensor 17 is also attached to the first pressure accumulation chamber 11. There is provided an electronically controlled high pressure regulator 19 for returning the fuel in the pressure accumulating chamber 11 to the fuel tank 7 via the bypass fuel passage 18 in accordance with the pressure value of.

The pressure accumulating chamber 11 and the injector 12 are also provided.
The length of the fuel passage 20 provided between the high pressure fuel pump 10 and the fuel storage chamber 11 is set shorter than the length of the fuel passage 15 provided between the high pressure fuel pump 10 and the pressure accumulating chamber 11.

Reference numeral 22 is an ECU for controlling the operations of the low pressure supply pump 9, the injector 12, and the high pressure regulator 19, and 23 is an ignition plug attached to the engine 5.

The high pressure fuel pump 10 includes a cylinder body 24 to which the low pressure regulator 14 is attached,
A pump housing 26, which is connected to the cylinder body 24 by a bolt 85 and houses a cam shaft 25 for driving a plunger, and a lubricating oil mounted on a side wall surface of the pump housing 26 opposite to the cam shaft driving side. The oil pump unit 58 for supply is provided.

As shown in FIG. 2, three pump chambers 32, 32, 32 are formed in parallel in the cylinder body 24, and the low pressure regulator is generated by lowering the plunger 33 in each pump chamber 32. The fuel that has passed through 14 is sucked in through the suction passages 31a and 31, and the pump chamber 3
Fuel pressurized by the ascent of the plunger 33 from 2 is discharged through the discharge passages 34, 34a.

Here, the discharge passage 34 is defined by the pump chamber 3
While it is formed linearly so as to be coaxial with 2,
The suction passage 31 is formed so as to be orthogonal to the pump chamber 32. The suction check valve is opened in each of the suction passages 31 during a suction stroke in which fuel is sucked into the pump chamber 32 and closes during a discharge stroke (compression stroke) in which fuel is discharged from the pump chamber 32. 66 are provided respectively. Further, each of the discharge passages 34 is provided with a discharge check valve 67 that closes during the suction stroke and opens during the discharge stroke.

In the pump housing 26, as shown in FIG. 2, three cylinder holes 35 having a circular cross section,
35, 35 are formed so as to be coaxial with each of the three pump chambers 32, 32, 32, and the respective cylinder holes 35 communicate with each other via a cam chamber 38 at the lower part of the drawing. A holding hole 35a having a diameter larger than that of the cylinder hole 35 is formed in the upper portion of each cylinder hole 35 so as to form a step portion, and a disc-shaped barrel 39 is arranged in each holding hole 35a. ing. Each barrel 39 is
The stepped portion of the holding hole 35a and the lower mating surface 24a of the cylinder body 24 are sandwiched and fixed. Further, a bottomed cylindrical slider 40 is slidably inserted in the cylinder axial direction at the bottom of each cylinder hole 35.

A through hole 39a is formed in the center of each barrel 39 so as to be coaxial with the pump chamber 32, and the plunger 33 is slidably inserted into the through hole 39a. The lower end flange portion 33a of the plunger 33 is in contact with the inner surface of the bottom wall of the slider 40.
A coil spring 41 is disposed between the barrel 39 and the lower end flange portion 33a of the plunger 33, and the spring 41 constantly urges the plunger 33 downward in the drawing. A tappet shaft 43 of a tappet roller 42 is axially inserted and fixed inside the bottom wall of the slider 40, and the tappet roller 42 is in rolling contact with the cam surface 25 a of the cam shaft 25. The slider 40 is prevented from rotating by the detent screw 40a shown in FIG. 5 and is held so as not to fall downward from the cylinder hole 35. As a result, the tappet shaft 43 and the cam shaft 25 are held in parallel with each other, and the slider 40 can be prevented from falling, so that the assemblability of the cam shaft 25 is improved.

A driving force input portion 44 is provided on the left side of the pump housing 26 in the drawing. The input unit 44
Is a base plate 47 attached to the end surface of a support boss portion 26a formed integrally with the pump housing 26 by bolts 45 and 46, and a sprocket 50 integrally connected to the left end of the cam shaft 25 in the drawing by a nut 48. And a sprocket 50, which is fixed to the crankshaft of the engine 5 by a chain 52.
It is connected to 7.

The oil pump unit 58 is of a trochoid type, and includes a pump plate 28 detachably mounted on the right side wall of the pump housing 26 in the drawing.
Plate cover 3 mounted on the outer surface of the plate 28
It has 0 and. The pump plate 28 closes an opening 27 formed in the right side wall of the pump housing 26. The opening 27 is for allowing the cam shaft 25 to be removed to the oil pump unit 58 side, and is formed to have a diameter larger than the maximum diameter of the cam shaft 25 when viewed on the projection plane in the axial direction. It is possible to move axially as it is from the mounted state.

A trochoidal type valve element 58 is disposed in a valve chamber 58a formed at the boundary between the plate cover 30 and the pump plate 28. The trochoidal type valve element 58 is fixed to the right end of the cam shaft 25. It is driven to rotate by. Further, the pump plate 28 is formed with an oil suction port 29a for sucking the oil in the oil pan 57, and the oil sucked from the suction port 29a is formed at the boundary portion between the pump plate 28 and the plate cover 30. It is introduced into the valve chamber 58b through the oil passage 29b which is formed, and is pressurized therein to the oil passages 29c and 29d, and the oil passage 29e formed at the boundary between the pump plate 28 and the right wall surface of the pump housing 26. It is supplied to the sliding surface of the plunger, etc., which will be described later. Further, the oil passage 29d is in communication with a bypass passage 60a which is opened by the opening / closing valve 60 when the pressure in the passage exceeds a predetermined value. Reference numeral 89 is a fixing bolt for fixing the flange portion of the plate cover 30 to the engine 5.

An end portion of the cam shaft 25 on the oil pump unit 58 side is pivotally supported by a tapered roller bearing 55 arranged in the pump plate 28, and a portion on the driving force input portion 44 side is a pump portion. It is rotatably supported by a tapered roller bearing 53 arranged in the boss portion 26a of the housing 26. The tapered roller bearings 55, 53 have conical rollers arranged between the inner race and the outer race, and have a structure that can be separated in the axial direction. Since the opening 27 is formed to have a large diameter as described above, the cam shaft 25 can be removed by removing the sprocket 50 from the cam shaft 25 and the oil pump unit 58 from the pump housing 26. It is removable outside.

The outer peripheral surface of the barrel 39 fitted into the holding hole 35a and the through hole 3 in which the plunger 33 slides.
Oil grooves 62 and 63 are formed in an annular shape on the inner peripheral surface of 9a, respectively, and these oil grooves 62 and 63 penetrate through the barrel 39 in the radial direction (cam axis direction) and through holes 64. Are in communication with each other. An oil passage 29e of the oil pump unit 58 communicates with an oil groove 62 of the barrel 39 at the right end of FIGS. 2 and 3 through an oil hole 29f, and the oil grooves 62 of the barrels are connected to the holding hole 35a. The oil holes 90 formed in the partition walls communicate with each other.

A gap a is provided between the lower portion of the outer peripheral surface of each barrel 39 and the lower portion of the inner peripheral surface of the holding hole 35a for dripping and supplying the lubricating oil in the oil groove 62 to the slider 40 side. Further, a cutout 91 is formed on the lower end surface of each barrel 39 to guide the lubricating oil dropped in the gap a to the inner surface of the cylinder hole 35. As a result, the lubricating oil from the oil pump unit 58 is transferred to the plunger sliding surface of each barrel 39 and the slider 40.
Is supplied to the sliding surface of the.

Here, as shown in FIG. 11, a seal member 88 is arranged between the barrel 39 and the cylinder body 24 and the plunger 33, and the seal member 88 causes the plunger 33 to pass through the barrel 39. The supplied lubricating oil and the fuel introduced into the pump chamber 32 do not mix.

The seal member 88 is a holder 88a, which is a spring plate and has a U-shaped cross section and surrounds the plunger.
An annular seal lip 88b made of an elastic material such as rubber
The seal portion 88c of the seal lip 88b is formed in a hemispherical shape when viewed in cross section. Further, the holder 88a is provided with a spring property so as to expand the U-shape, whereby the seal portion 8a is formed.
8c is in pressure contact with the surface to be sealed. In addition,
The seal material 88 may be an O ring, an X ring, or the like.

The length of the sealing material 88 from the sliding contact of the sealing material 88 to the upper edge of the oil groove 63 (L2) when the plunger 33 is at the rising end position.
At a position longer than the length (L1) from the sliding contact to the upper end surface of the plunger 33, that is, the plunger 33.
It is located near the tip side of. In this case, it is necessary to set the length L1 to be slightly longer than the plunger stroke so that the sealability is not hindered.

The gap (S2) between the plunger 33 and the barrel 39 below the sealing material 88 is
It is set to be smaller than the gap (S1) between the plunger 33 and the cylinder body 24 above the sealing material 88. That is, the plunger 33 is guided mainly in a state of sliding contact with the barrel 39 side rather than the cylinder body 24 side.

Next, the function and effect of the above embodiment will be described.
In this embodiment, when the engine 5 starts, the crankshaft 8
7 driving force is transmitted to the cam shaft 25 by the chain 52,
The cam 25 rotates in the direction of the arrow in FIG. 5, the cam 25a of the cam shaft 25 moves the plunger 33 upward in the drawing via the tappet roller 42 and the slider 40, and the return spring 41 moves the plunger 33 downward. Move to.

When the plunger 33 descends, the discharge side check valve 67 closes the discharge passage 34, the suction side check valve 66 opens the suction passage 31, and the fuel is pumped from the suction passage 31. It flows into the chamber 32. next,
When the plunger 33 rises, the suction passage 31 is closed by the suction check valve 66, and the fuel pressure in the pump chamber 32 rises, and when the pressure exceeds a predetermined value, the discharge passage 34 is opened. And the fuel is discharged into the discharge passage 3
4 is supplied to the first pressure accumulating chamber 11. Then, the fuel once stored in the first pressure accumulating chamber 11 is supplied from the injector 12 to the combustion chamber according to the combustion stroke of the engine 5.

In such a fuel supply device, the operating state of the engine 5 changes, the suction amount of the high-pressure fuel pump 10 becomes smaller than the discharge amount of the low-pressure supply pump 9, and the low-pressure supply pump 9 and the high-pressure fuel pump 10 are discharged. When the fuel pressure between the low pressure regulator 14 and the fuel pressure in the second pressure accumulation chamber 72 of the low pressure regulator 14 in the present embodiment exceeds a predetermined value, the diaphragm 71 of the low pressure regulator 14 rises against the biasing force of the spring 74. Then, the valve body 81 opens the relief passage 70d, whereby fuel is returned to the fuel tank 7 through the fuel passage 16. At this time, the air accumulated in the second pressure accumulation chamber 72 is also returned to the fuel tank 7. Thereby, the fluctuation of the fuel pressure in the fuel passage 31 can be reduced. As a result, the fuel discharge amount and discharge pressure from the high-pressure fuel pump 10 are stabilized.

Further, since the inside of the low pressure regulator 14 is the second pressure accumulating chamber 72, the pressure fluctuation on the suction side of the high pressure fuel pump 10 can be absorbed, and as a result, the discharge pressure and discharge amount of the high pressure fuel pump 10 are further stabilized. Can be converted.

On the other hand, since the high-pressure fuel pump 10 has a structure in which fuel is intermittently sucked in and discharged by the reciprocating motion of the plunger 33, the discharge pressure from the high-pressure fuel pump 10 varies, and Although the pressure in the pressure accumulating chamber 11 fluctuates, in the present embodiment, this first pressure accumulating chamber 1
The pressure fluctuation in 1 is suppressed as follows. That is, the fuel pressure in the first pressure accumulating chamber 11 is constantly detected by the first fuel pressure sensor 17, and when the fuel pressure detected by the sensor 17 exceeds a predetermined value, the electronically controlled high pressure regulator 19
Bypasses the fuel to the fuel tank 7, whereby the fluctuation of the discharge pressure from the high-pressure fuel pump 10 can be absorbed and the pressure in the first pressure accumulating chamber 11 can be stabilized, and as a result, the fuel can be supplied from the injector 12 to the combustion chamber. The amount of fuel consumed can be stabilized.

Further, in this embodiment, the length of the fuel passage 20 from the pressure accumulating chamber 11 to the injector 12 is set to the pressure accumulating chamber 1
1 is shorter than the length of the fuel passage 15 from the high-pressure fuel pump 10, that is, the pressure accumulation chamber 11 is connected to the injector 12
Since it is arranged close to, the back pressure fluctuation due to fuel injection and stop can be more surely absorbed by the pressure accumulating chamber 11, and thus the fuel supply amount to the injector 12 can be stabilized.

In this embodiment, the pump chamber 32, the discharge passages 34, 34a, and the suction passage 3 are provided in the cylinder body 24.
1, 31a are arranged, the discharge check valve 67 is installed in the discharge passage 34, and the suction check valve 66 is installed in the suction passage 31, respectively, that is, one component (cylinder body 2).
4) Inside the pump chamber 32 and each passage 34, 34a, 31,
Since 31a is formed, the seal itself, which is required when the pump chamber 32 is formed so as to extend over two parts, or when each passage is formed so as to communicate with other parts, is unnecessary. Therefore, the possibility of fuel leakage from the seal portion can be reduced.

Further, since a plurality of pump chambers 32 are arranged in one cylinder body 24, the processing of each pump chamber 32 can be facilitated and the sealing property can be improved also from this point.
Therefore, the injection pressure of fuel can be increased.

The lubrication operation of the sliding portion in the high pressure fuel pump 10 is performed as follows. When the valve body 58a of the oil pump unit 58 rotates due to the rotation of the cam shaft 25, the lubricating oil in the oil pan 57 is sucked through the suction port 29a, and the oil passages 29b to 29e and the oil hole 29.
The oil is supplied to the oil groove 62 via f, and a part of it is dripped along the inner peripheral surface of the cylinder hole 35 through the gap a and the notch 91, and is dropped on the sliding surface between the cylinder hole 35 and the slider 40. Supplied.

The remaining portion of the lubricating oil supplied to the oil groove 62 enters the oil groove 63 through the through hole 64, and the oil groove 63 penetrates the through hole 39a of the barrel 39.
Is supplied to the gap between the plunger 33 and the plunger 33 to lubricate the sliding surfaces of the two and to prevent seizure and wear of the plunger 33.

In this embodiment, the oil groove 63 for supplying the lubricating oil is arranged near the center of the barrel 39 in the axial direction, but the oil groove 63 may be formed closer to the sealing material 88 side. Of course, the closer to the seal material 88 side, the more the lubricating oil can be supplied to a wide range of the sliding surface of the plunger 33.

Here, the through hole 39a and the plunger 33 are provided.
When the gap between and is communicated with the pump chamber 32, the lubricating oil supplied to the gap and the fuel introduced into the pump chamber 32 may be mixed. In the present embodiment, the seal material 88 that defines the gap on the oil groove 63 (lubricating oil supply portion) side and the pump chamber 32 side is provided, so that mixing of the lubricating oil and fuel can be avoided.

In this case, the sealing material 88 is formed by fixing a seal lip 88a to a U-shaped holder 88a which is biased by a spring force in the expanding direction, and the U-shaped opening is pumped. Since it is arranged toward the chamber 32 side, during operation, a pump chamber side pressure much higher than the cam chamber side pressure acts on the U-shape of the seal member 88 to further expand the seal member 88. The seal portion 88c surely comes into sliding contact with the surface to be sealed. As a result, the sealing property can be improved, and the mixing of the lubricating oil and the fuel can be more reliably avoided.

The length L2 from the sealing point of the sealing material 88 to the upper edge of the oil groove 63 is the length L1 from the sealing point to the upper end surface of the plunger 33 located at the rising end.
Since the length is set longer, the plunger sliding surface length (L1) to which no lubricating oil is supplied can be shortened, and the seizure wear of the plunger 33 can be suppressed accordingly. When the plunger 33 is located at the rising end, the pressure in the pump chamber is high, and a large force acts on the plunger 33. When the plunger 33 falls, the surface pressure with the side surface is increased. Although it can be increased, since the length L1 is shortened as described above, seizure or the like can be prevented in this case as well. In this case, it is preferable that the length L1 is shorter, but in order to secure the sealing function,
It is set to be slightly longer than the stroke of the plunger 33.

Here, the sealing material 88 is, for example, as shown in FIG.
As shown in FIG.
It is also possible to recess b and dispose it in the seal groove 33b. In this case, the shape, structure, and arrangement direction of the sealing material 88 are the same as those in FIG. As a result, the length L
Since 1 can be further shortened, the problems of seizure and wear can be prevented more reliably.

Further, with the seal member 88 as a boundary, the gap S2 between the plunger 33 on the lubricating oil supply portion side and the plunger sliding hole (through hole 39a) is set to the plunger 3 on the pump chamber side.
3 is set smaller than the gap S1 between the plunger sliding hole, the plunger 33 is mainly supported by the through hole 39a of the barrel 39 to which the lubricating oil is supplied, and the gap on the pump chamber 32 side is large, so that the friction is reduced. A force is not generated so much, so that also from this point, the occurrence of seizure wear of the plunger 33 can be suppressed.

Further, in disposing the seal member 88, the seal member 88 is sandwiched between the holding hole 24a of the cylinder body 24 and the upper end surface of the barrel 39, so that the seal member 88 is prevented from moving. Since it is not necessary to provide a groove or the like for processing, the number of processing steps can be reduced.

The pressure chamber side portion of the plunger 33 is supported by the inner peripheral surface of the pump chamber 32 formed in the cylinder body 24, and the lubricating oil supply portion side portion is the through hole 39a of the barrel 39.
Since the plunger sliding surface is composed of the cylinder body 24 and the barrel 39 as separate parts, it is not necessary to machine long holes, and it is easy to change the hole diameter for setting S1 and S2. Become.

Further, since the barrel 39 which mainly supports the plunger 33 is formed separately from the cylinder body 24 and the pump housing 26 and has a common shape for all the plungers, maintenance and replacement at the time of wear or the like can be performed. It can be done easily.

Furthermore, since the gap a and the notch 91 are formed in the oil groove 62, the lubricating oil is added to the slider 4.
The slider 40 can also be supplied with 0 to suppress seizure and wear of the slider 40.

Here, in the apparatus of this embodiment, the cam shaft 25
When removing the sprocket 50 from the inside of the pump housing 26, first, the sprocket 50 is removed from the cam shaft 25, and the oil pump unit 58 is removed from the wall surface of the pump housing 26. Then, the outer race of the tapered roller bearing 55 is removed together with the pump plate 28, and the right end of the cam shaft 25 faces the outside in the opening 27 with the roller and the inner race of the tapered roller bearing 55 mounted.
Next, when the cam shaft 25 is pulled out in the axial direction, the cylindrical roller bearing 5
The outer race No. 3 remains on the pump housing 26 side, and the cam shaft 25 is removed outward with the rollers and the inner race being mounted on the cam shaft 25.

When the cam shaft 25 is assembled in the pump housing 26, the cam shaft 25 is inserted inward from the opening 27 in the reverse order of the above-mentioned case, and each tapered roller bearing 53, 5 is inserted.
The five parts are connected and the left end of the cam shaft 25 is projected outward. After that, the pump plate 28 is bolted and fixed to the pump housing 26, and the sprocket 50 is attached to the left protruding portion of the cam shaft 25.

As described above, in this embodiment, the opening 27 having a diameter larger than the maximum diameter of the cam shaft 25 is formed on the right side wall of the pump housing 26, and the opening 27 is closed by the oil pump unit 58. Therefore, when assembling and dismounting the cam shaft, the cam shaft 25 can be assembled or disassembled independently or together with the pump unit 58, and the workability is good.

Since the right end of the cam shaft 25 is supported by the pump plate 28 via the bearing 55, the structure is simple as compared with the case where the bearing supporting boss is formed in the pump housing 26. Is. Further, since tapered roller bearings that can be separated in the axial direction are used as the bearings 55 and 53, the cam shaft 25 can be removed and assembled simply by moving it in the axial direction, and the workability is extremely good.

In the above embodiment, the three suction passages 3
Although the suction side check valve 66 is provided in all of the above items 1, all or a part of the suction side check valve can be omitted. FIG. 13 is a diagram showing an embodiment in the case where all of the suction side check valves are abolished, in which the same reference numerals as those in FIG. 5 indicate the same or corresponding portions.

In the present embodiment, the suction passage 31 is formed so as to communicate with the pump chamber 32 in the lateral direction, and no suction check valve is provided in the suction passage 31. The suction port 31b communicating with the pump chamber 32 of the suction passage 31 is formed at a position closed by the plunger 33 in the middle of the compression stroke.

Therefore, in this embodiment, a part of the fuel introduced into the pump chamber 32 is pushed back into the suction passage 31 at the beginning of the compression stroke, but the remaining portion of the fuel is blocked by the suction port 31b by the plunger 33. After being discharged, it is compressed in the same manner as in the above embodiment, and the discharge check valve 67 is pushed open to be discharged into the discharge passage 34. In this case, since the pressure inside the pump chamber 32 rises when the plunger 33 has sufficiently entered the pump chamber 32, a sufficient sealing function can be provided in the gap around the plunger 33, and the sealing material 88 can be eliminated. Become.

As described above, in this embodiment, the suction port 31
Since b is closed by the plunger 33 in the middle of the compression stroke, the suction check valve can be eliminated. In addition, in this way, the suction port 31
It may be configured to close b, and a suction check valve may be arranged in the suction passage 31. By doing so, it is possible to prevent the return of the fuel in the early stage of the compression stroke, and it is possible to increase the compression pressure of the fuel accordingly. Also suction port 31
After b is closed by the plunger 33, the rise in the pressure acting on the suction check valve stops, so that the pressure resistance of the suction check valve can be set low.

Further, in the above-mentioned case, it is not always necessary to close all the suction passages 31 by the plunger 33, and some suction passages are shown in FIGS.
Similar to the first embodiment, the structure may be such that it is not closed by the plunger 33, and the suction side check valve is arranged in the suction passage. This structure can be realized by changing the shape of the cam 25 so as to change the stroke of the plunger 33.

[0065]

As described above, according to the high pressure fuel pump of the first aspect of the present invention, the opening for inserting the cam shaft in the axial direction is formed on the opposite side of the pump housing from the cam shaft driving force input side. Since the opening is closed by the lubricating oil pump, the oil pump also serves as a lid member, and therefore, a dedicated lid member can be eliminated and the number of parts can be reduced.

According to the second aspect of the invention, since the oil passage is formed at the boundary between the pump plate and the plate cover which form the casing of the oil pump, the lubricating oil passage can be secured with a simple structure. There is an effect that the structure can be simplified.

According to the third aspect of the present invention, since the bearing supporting the opening side portion of the cam shaft is supported by the pump plate, the size of the opening is not restricted by the diameter of the bearing. There is an effect that it can be set to a large value freely and workability when the cam shaft is inserted into or removed from the opening is improved.

Further, in the invention of claim 4, since the bearing for driving force input side is supported by the pump housing, there is an effect that the structure can be simplified without impairing the workability of assembling and dismounting the cam shaft.

[Brief description of drawings]

FIG. 1 is a schematic partial cross-sectional view showing the overall configuration of a fuel supply device according to an embodiment of the present invention.

FIG. 2 is a sectional front view of a high-pressure fuel pump applied to the fuel supply device.

FIG. 3 is an enlarged sectional front view of a barrel portion of the high-pressure fuel pump.

FIG. 4 is a left side view of the high-pressure fuel pump.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a right side view of the high-pressure fuel pump.

FIG. 7 is a right side view of a partial cross section of the high-pressure fuel pump.

FIG. 8 is a plan view of the high-pressure fuel pump.

FIG. 9 is a sectional plan view of a barrel portion of the high-pressure fuel pump.

FIG. 10 is a sectional side view of a low pressure regulator applied to the fuel supply device.

FIG. 11 is an enlarged sectional front view of a sealing material used in the high-pressure fuel pump.

FIG. 12 is a sectional side view showing a modified example of the seal member arrangement structure of the high-pressure fuel pump.

FIG. 13 is a sectional side view showing a suction port closing structure by a plunger of the high-pressure fuel pump.

[Explanation of symbols]

 1 Fuel Supply Device 5 Engine (Fuel Injection Type Internal Combustion Engine) 10 High Pressure Fuel Pump 25 Cam Shaft 26 Pump Housing 27 Opening 28 Pump Plates 29b and 29c Oil Passage 30 Plate Cover 33 Plunger 53 Driving Force Input Side Bearing 55 Opening Side Bearing 58 oil pump unit 58a valve body

Claims (4)

[Claims] 1. A high pressure fuel pump used in a fuel supply system for a fuel injection type internal combustion engine, wherein a cam shaft for driving a plunger is inserted and arranged in a pump housing, and a portion of the pump housing opposite to a cam shaft driving force input side. An opening into which the cam shaft can be inserted in the axial direction is formed, and a valve body of an oil pump for supplying lubricating oil to a plunger sliding portion is attached to an end portion of the cam shaft on the opening side, and a casing of the oil pump. Is attached to the pump housing so as to be able to close the opening and be detachable. 2. The casing of the oil pump according to claim 1, comprising a pump plate for closing the opening of the pump housing and a plate cover attached to the pump plate, and the plate cover and the pump plate. A high-pressure fuel pump, wherein at least a part of an oil passage is formed at a boundary portion of the fuel pump. 3. The high-pressure fuel pump according to claim 2, wherein the pump plate supports a bearing that axially supports the opening-side portion of the cam shaft. 4. The high-pressure fuel pump according to claim 3, wherein a bearing that supports the driving force input side portion of the cam shaft is supported by the pump housing.