JP3199105B2 - High pressure fuel supply pump - Google Patents

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 supply pump used in an internal combustion engine (hereinafter referred to as an "internal combustion engine").

[0002]

2. Description of the Related Art FIG. 26 shows a fuel supply system for a gasoline engine using a conventional plunger pump type high pressure fuel supply pump. The fuel pump 301 has a fuel pump 3
02 is stored, and several tens of
After the fuel is pressurized to 0 kpa, it is pressure-fed to the suction port 304 of the fuel filter 303. The discharge port 305 of the fuel filter 303 is connected to the suction port 307 of the high-pressure fuel supply pump 306. The driving force due to the reciprocating motion of the piston 311 is transmitted to the camshaft 310 by a connecting mechanism including a connecting rod 312, a crankshaft 313, and a belt 314.
6 is rotated. Suction port 30
7 is pressurized to a high pressure of several Mpa to several tens Mpa by a high-pressure fuel supply pump 306 and discharged to a common rail 309 via a discharge port 308.
The high-pressure fuel stored in the common rail 309 is supplied to an injector 317 provided in each cylinder of the engine via a branch passage 315. Then, high-pressure fuel is directly injected from the injector 317 into the combustion chamber 316 in the cylinder.

[0003] Excess low-pressure fuel output from the bypass discharge port 318 of the high-pressure fuel supply pump 306 is returned to the fuel tank 301 through a return passage 319. The common rail 309 is provided with a pressure sensor 320 for detecting the pressure of the fuel inside the common rail 309, and the pressure signal detected by the pressure sensor 320 is transmitted to the electronic control unit 3.
21. The electronic control unit 321 adjusts the energization timing of the solenoid valve 322 such that the fuel injection pressure becomes an optimum value according to the pressure signal detected by the pressure sensor 320 and the engine operation state such as the engine speed and load. By controlling, the amount of fuel discharged to the common rail 309 is controlled. Further, the electronic control unit 321 outputs a control signal to the injector 317 in order to control the fuel injection timing and the injection period in accordance with the operation state of the engine such as the engine speed and the load state.

[0004]

However, in such a conventional high-pressure fuel supply pump, there is a gap of several μm between the inner peripheral wall of the cylinder and the outer peripheral wall of the plunger due to the plunger sliding.
A clearance of m to several tens of μm is required. At the time of fuel injection, when the fuel in the fuel pressurizing chamber is pressurized, fuel leaks from the clearance, and the fuel having a lower viscosity than the lubricating oil dilutes the lubricating oil of the engine, thereby lubricating and cooling each part of the engine. Insufficiently reduces engine reliability. Similarly, the lubricating oil guided for lubricating the sliding portion inside the pump adheres to the plunger to form an oil film, and the sliding of the plunger causes the fuel oil film on the inner peripheral wall of the cylinder and the lubricating oil on the outer peripheral wall of the plunger to slide. When the oil film comes into contact with the oil film, an oil leak occurs in which the lubricating oil mixes with the fuel. Due to this oil leak, the lubricating oil in the engine is gradually consumed, and the lubrication and cooling of each part of the engine become insufficient due to the shortage of the lubricating oil. Therefore, the reliability of the engine is lowered or the lubricating oil needs to be replenished frequently. Also, lubricating oil in the fuel can cause nozzle and injector deposits.

In order to solve such a problem, it is conceivable to reduce the amount of fuel leakage by mounting a sealing member for sealing the outer peripheral wall of the plunger on the inner wall of the cylinder. However, in order to mount the seal member on the inner peripheral wall of the cylinder, it is necessary to provide a space for accommodating the seal member on the inner wall of the cylinder, and there is a problem that the number of processing steps of the cylinder increases and the size of the cylinder increases. If the space for mounting the seal member is secured without increasing the size of the cylinder in the axial direction, the length of the high-pressure seal between the cylinder and the plunger is shortened, and the sealing efficiency is reduced.
In addition, the number of components other than the sealing member is increased, so that there is a disadvantage that the cost is increased. Further, when a low-viscosity gasoline having poor self-lubricating properties causes sliding scratches having a depth of several tenths to several μm on the outer peripheral wall of the plunger in a sliding portion with the cylinder, the sliding scratches come into contact with the seal member. However, there is a problem that the seal member is damaged and the sealing performance is reduced, and the amount of fuel leaking through the sliding scratch increases.

[0006] In order to prevent the occurrence of sliding scratches on the outer peripheral wall of the plunger, it is conceivable to increase the hardness of the plunger by heat treatment, plating, or the like. However, if the hardness of the plunger is increased, the cylinder is likely to be worn. If the hardness of the cylinder is increased in order to prevent the wear of the cylinder, it is not possible to prevent the plunger from having a sliding scratch. Although it is possible to reduce the occurrence of sliding scratches by introducing lubricating oil into the sliding portion between the plunger and the cylinder, there is a problem that oil leak increases sharply. In addition, by increasing the urging force of the seal member in contact with the plunger, it is possible to maintain the sealing property of the seal member even if the plunger is slid, but the wear rate of the seal member is increased, so that it is practical. Do not follow.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a highly reliable high-pressure fuel supply pump which maintains a good seal between a cylinder and a plunger without increasing the size of the cylinder. The purpose is to provide.
It is another object of the present invention to provide a highly reliable high-pressure fuel supply pump that maintains good sealing performance between a cylinder and a plunger by preventing damage to a seal member that reduces fuel leakage. .

[0008]

According to a first aspect of the present invention, there is provided a high-pressure fuel supply pump according to the present invention, wherein a plunger is formed by an inner wall forming a sliding hole communicating with a fuel intake passage and a discharge passage. And a cylinder that slidably and slidably supports the cylinder, and determines a discharge timing of the fuel introduced from the suction passage into the fuel pressurizing chamber that is a part of the sliding hole and pressurized by the reciprocating motion of the plunger. A discharge timing control valve, a tappet that reciprocates with the plunger and is supplied with lubricating oil, a driving unit that reciprocally drives the plunger and the tappet, and the plunger is disposed outside the cylinder in the axial direction of the plunger. A sealing portion that seals the lubricating oil and the fuel with the outer peripheral wall in a liquid-tight manner, and has an annular member that slides on the outer peripheral wall by reciprocation of the plunger; Characterized in that it comprises a and.

According to a second aspect of the present invention, there is provided a high-pressure fuel supply pump comprising: a cylinder having a sliding hole formed by an inner wall communicating with a fuel suction passage and a discharge passage; And a plunger that pressurizes by reciprocating the fuel introduced from the suction passage into the fuel pressurizing chamber that is a part of the sliding hole, and reciprocates with the plunger to supply lubricating oil. A tappet, a driving unit for reciprocatingly driving the plunger and the tappet, and sealing the lubricating oil and the fuel with the outer peripheral wall of the plunger in a liquid-tight manner outside the cylinder in the axial direction of the plunger, and reciprocating the plunger. A seal member having an annular member that slides on the outer peripheral wall by movement;
It is characterized by having.

Further, a part of the sliding hole of the high-pressure fuel supply pump according to the present invention is, as described in claim 3, an inner wall of a projection formed integrally with the cylinder and protruding in the axial direction of the plunger. Is desirably formed. Further, in the high-pressure fuel supply pump according to claim 4 of the present invention,
A length of the annular member from the cylinder side end to the seal member side end of the cylinder inner wall that slides on the plunger is longer than a lift stroke of the plunger.

Further, in the high-pressure fuel supply pump according to the fifth aspect of the present invention, the axial length of the non-contact portion formed so as not to slide on the plunger all around the inner wall forming the sliding hole. Is a part or all of the length from the cylinder side end of the annular member to the seal member side end of the cylinder inner wall that slides on the plunger.

According to a sixth aspect of the present invention, there is provided a high-pressure fuel supply pump including a fuel reservoir defined by the seal member, the plunger, and the cylinder. Further, it is desirable that the annular member of the high-pressure fuel supply pump of the present invention is made of rubber. Furthermore, a high-pressure fuel supply pump according to an eighth aspect of the present invention is the high-pressure fuel supply pump according to the sixth aspect, wherein the fuel reservoir communicates with a path having a pressure equal to the atmospheric pressure. .

According to a ninth aspect of the present invention, there is provided a high-pressure fuel supply pump according to the first, second, third, fourth, fifth or seventh aspect, wherein the sliding hole is formed. An annular fuel reservoir is provided on the inner wall, and the fuel reservoir communicates with a path having a pressure equal to the atmospheric pressure.

[0014]

According to the high-pressure fuel supply pump of the present invention, the sealing member for sealing the lubricating oil and the fuel in a liquid-tight manner on the outer peripheral wall of the plunger is provided outside the cylinder in the axial direction of the plunger. By providing the cylinder, the size of the cylinder can be reduced. This makes it possible to reduce the urging force of the urging means for urging the plunger, for example, by reducing the weight of the member that reciprocates with the plunger by downsizing, so that a smaller compression coil spring is mounted and the high-pressure fuel supply pump is mounted. Can be made smaller.

According to the high-pressure fuel supply pump according to the third aspect of the present invention, a part of the sliding hole is formed by the inner wall of the protruding portion of the cylinder protruding in the axial direction of the plunger.
The seal member can be attached to the outer peripheral wall of the projection without attaching the seal member to the inner wall of the projection. Therefore, it is possible to reduce the deformation of the projection, which is the installation site of the seal member, due to the thermal stress during the heat treatment of the cylinder, and to prevent the cylinder from being cracked. In addition, the number of steps in processing steps such as grinding after the heat treatment can be reduced.

Further, according to the high pressure fuel supply pump of the present invention, the length from the cylinder side end of the annular member to the seal member side end of the cylinder inner wall sliding on the plunger is equal to the length of the plunger. Since the length is longer than the lift stroke, sliding scratches generated on the outer peripheral wall of the plunger do not reach the annular member. Therefore, it is possible to prevent the annular member from being damaged and to reduce fuel leakage from between the annular member and the plunger.

Further, according to the high-pressure fuel supply pump of the present invention, since the fuel pool for storing leaked fuel is formed by the seal member, the plunger and the cylinder, the fuel pool is formed outside the cylinder, not inside the cylinder. Since it can be formed, the length of the cylinder in the axial direction of the plunger can be reduced, and the number of processing steps can be reduced.

Further, according to the high-pressure fuel supply pump of the present invention, the rubber member is used for the annular member, so that the sealing performance with the plunger is further improved. Furthermore, according to the high-pressure fuel supply pump according to claim 8 or 9 of the present invention, by connecting a fuel reservoir formed inside or outside the cylinder for storing leaked fuel and a path having a pressure equal to the atmospheric pressure, Since the fuel leaked to the fuel reservoir can be discharged through a path having a pressure equal to the atmospheric pressure, high pressure is not applied to the seal member. For this reason,
Even if the structure of the seal member is simplified, it is possible to suppress further leakage of fuel from the sliding portion between the seal member and the plunger.

[0019]

An embodiment of the present invention will be described with reference to the drawings. First Embodiment A high-pressure fuel supply pump for a gasoline engine according to a first embodiment of the present invention is shown in FIGS. As shown in FIG. 4, a pump body 10 of the high-pressure fuel supply pump has bolts 103 attached to a head cover 100 which is a part of the engine housing.
It is fixed by. The bottom of the pump body 10 is provided with a camshaft 101 for opening and closing an intake / exhaust valve (not shown).
The pump main body 10 is reciprocally driven by the pump cam 102 which comes into contact with the pump cam 102 mounted on the cam shaft 101 and rotates integrally with the cam shaft 101. As shown in FIG.
The pump body 10 connects the suction port 12 in which the suction passage 12 a is formed, the solenoid valve 20 and the delivery valve 30 to the cylinder 1.
1 is stored in the upper part. The other part of the pump body 10 is surrounded by a cylindrical tappet guide 40. The tappet guide 40 is fixed to the cylinder 11 by a screw 60 or a pin.

An annular fuel reservoir 11b is formed on the inner wall of the cylinder 11, which supports the plunger 43, which will be described later, so as to be able to reciprocate and slide. The fuel reservoir 11b communicates with the suction passage 12a via the return passage 17. A suction passage 12a is formed in the suction port 12, and fuel is supplied from a fuel pump (not shown). The suction passage 12a communicates with the fuel passage 13 and a fuel reservoir 1 through a return passage 17.
1b.

The solenoid valve 20 is vertically inserted into the cylinder 11, and a valve body 22 having a valve seat 21 and a fuel supply passage formed therein is inserted into the solenoid valve 20. The valve body 23 is disposed on the valve body 22 so as to be able to contact and separate from the valve seat 21. The end surface of the valve body 22 in the −Z-axis direction is a plate 24 and a plate 24.
The end face in the −Z-axis direction has a washer 25 and a washer 2.
5 is in surface contact with the cylinder 11.
An annular fuel gallery 14 is formed on the inner wall of the cylinder 11 around the solenoid valve 20, and the fuel gallery 14 communicates with the fuel passage 13 and the communication passage 26.

The delivery valve 30 is connected to a common rail (not shown) by a fuel steel pipe (not shown). The delivery valve 30 is fixed to the cylinder 11 by screw connection, and the fuel passage 30 a communicates with the discharge passage 15. The discharge valve body 31 is compressed by a compression coil spring 32 so that the valve seat 3 is closed.
It is biased to 3. When the pressure in the fuel pressurizing chamber 16 becomes equal to or higher than a predetermined pressure, the discharge valve body 31 lifts against the urging force of the compression coil spring 32, and the discharge passage 15 and the discharge port 34 communicate with each other through the fuel passage 30a. .

The tappet 41 is formed in a cylindrical shape with a bottom, and the bottom surface 41a is in contact with the pump cam 102 of FIG. The tappet 41 is slidably supported on the inner wall of the tappet guide 40. Inner wall of tappet guide 40 and tappet 4
A cylindrical oil sump 42 is formed between the tappet 41 and the outer wall of the tappet 41.
Lubricating oil is supplied in order to prevent seizure. The tappet 41 does not lock on the pin 61 even at the bottom dead center position of the plunger 43 shown in FIG. 1, but when the tappet 41 is assembled to the head cover 100 in FIG.

The plunger 43 is slidably supported in the axial direction by the cylinder 11 forming the sliding hole 11a, the inner wall of the projection 50 described later, and the seal member 70. The spring seat 44 is urged in the −Z-axis direction in FIG. 1 by the compression coil spring 45 and is in contact with the inner bottom surface of the tappet 41. The head portion 43a of the plunger 43 is sandwiched between the inner bottom surface of the tappet 41 and the spring seat 44, and is urged by the spring seat 44 in the −Z-axis direction in FIG. The fuel pressurizing chamber 16 is formed by the end surface of the plunger 43 in the + Z axis direction in FIG. 1, the inner wall of the cylinder 11, and the end surface of the solenoid valve 20.

The protrusion 50 is formed integrally with the lower part of the cylinder 11 so as to protrude from the cylinder 11.
As shown in FIG. 5, a return passage 53 communicating with the return passage 18 is formed in the axial direction. The seal member 70 is fitted to the outer peripheral wall of the projection 50 by press fitting. At the time of press-fitting of the sealing member 70, the sealing member 7
0 is formed, and a tapered surface 51 is formed to prevent the seal member 70 from being damaged at the time of press-fitting. The seal member 70 includes a support member 71 and an inner wall covering portion 7.
2. It comprises an outer wall covering portion 73 and a lip portion 74.

The support member 71 is formed in a bottomed cylindrical shape having a circular through hole at the bottom. The inner wall covering portion 72, the outer wall covering portion 73, and the lip portion 74 are made of rubber and are integrally formed. When the sealing member 70 is press-fitted into the projection 50, the inner wall covering portion 72 bites into the annular groove 52 formed on the outer peripheral wall of the projection 50, thereby preventing the sealing member 70 from falling off.

The lip 74 is integrally formed in an annular shape by an upper lip 74a and a lower lip 74b, and is in contact with the outer peripheral wall of the plunger 43 with elasticity. The inner diameter of the lip portion 74 is formed such that the inner diameter gradually decreases from the central portion in the axial direction toward the upper lip 74a and the lower lip 74b. Upper lip 74a and lower lip 74
b denotes an annular sliding portion with the outer peripheral wall of the plunger 43, wherein the front and rear wall surfaces of the annular sliding portion in the axial direction form a predetermined angle with the outer peripheral wall of the plunger 43, respectively.
Mainly reduces the amount of fuel leaking from the fuel pool 54 to the tappet 41 side, and mainly reduces the amount of lubricating oil leaked from the sliding portion between the tappet guide 40 and the tappet 41 to the fuel pool 54 by the lower lip 74b. Reduce. Upper lip 7
4a and the lower lip 74b have a function of thinning the fuel oil film covering the outer peripheral wall of the plunger 43, so that the amount of fuel or oil leakage can be reduced.

A fuel reservoir 54 is formed by the end face of the projection 50, the outer peripheral wall of the plunger 43, and the inner wall covering portion 72. The fuel reservoir 54 communicates with the return passage 18 via the return passage 53. The operation of the high-pressure fuel supply pump will be described with reference to FIGS. 1, 2 and 4 by dividing the process into (1) a fuel suction stroke and (2) a fuel pressurizing and feeding process.

(1) Fuel suction stroke The pump cam 10 is rotated with the rotation of the valve camshaft 101.
2 rotates, the tappet 41 and the spring seat 44
At the same time, the plunger 43 reciprocates. Plunger 43
Is located at the maximum position in the + Z-axis direction, which is the top dead center, the energization of the solenoid (not shown) of the solenoid valve 20 is cut off. Then, the valve element 23 is separated from the valve seat 21 by the urging force of a compression coil spring (not shown), and the solenoid valve 20 is opened. At this time, when the plunger 43 moves in the −Z-axis direction, the low-pressure fuel discharged from the fuel pump is supplied to the suction passage 12 a, the fuel passage 13, and the fuel gallery 1.
4. The fuel flows into the fuel pressurizing chamber 16 through the communication passage 26.
When the plunger 43 is located at the maximum position in the −Z-axis direction, which is the bottom dead center, the maximum amount of low-pressure fuel flows into the fuel pressurizing chamber 16.

(2) Pressurizing and Pressure Feeding Process of Fuel In the process in which the plunger 43 moves in the + Z axis direction,
When the plunger 43 reaches a position corresponding to a desired fuel discharge amount, the solenoid of the solenoid valve 20 is energized by an electronic control unit (not shown). Thereby, the valve element 23
Moves in the + Z-axis direction and contacts the valve seat 21. That is,
The solenoid valve 20 is closed. Then, the plunger 43
Further moves in the + Z axis direction, the fuel in the fuel pressurizing chamber 16 becomes high pressure, and the discharge valve body 31 separates from the valve seat 33, so that the discharge passage 15, the fuel passage 30a, the discharge port 3
High-pressure fuel is discharged from the delivery valve 30 to a common rail (not shown) through the fourth valve 4. When fuel is supplied to the common rail and the pressure difference between the fuel upstream side and the fuel downstream side of the discharge valve body 31 becomes small, the discharge valve body 31 comes into contact with the valve seat 33 by the urging force of the compression coil spring 32 and the delivery valve 30 is closed. Give a valve. This prevents the fuel from flowing backward from the fuel downstream side. When the fuel is pressurized and pumped, a part of the high-pressure fuel in the fuel pressurizing chamber 16 is supplied to the plunger 43 and the cylinder
1 may flow into the sliding portion. The fuel that has flowed in accumulates in the fuel reservoir 11b shown in FIG. 1, and is returned to the suction passage 12a through the return passage 17. Although fuel pressure is applied to the suction passage 12a at a low pressure, the fuel stored in the fuel pool 11b may flow in the -Z axis direction. This fuel is stored in the fuel pool 54
And the fuel is finally returned to the fuel tank from the return connector 19 via the return passage 53 and the return passage 18, so that the fuel does not mix into the engine oil. Since the pressure in the return passage 18 is equal to the atmospheric pressure, the fuel pressure in the fuel reservoir 54 is reduced, and no high pressure is applied to the seal member 70 forming the fuel reservoir 54. For this reason, even if the structure of the seal member 70 itself is simplified, it is possible to suppress leakage of the leaked fuel accumulated in the fuel reservoir 54 from the sliding portion between the lip portion 74 and the plunger 43. Further, the coupling structure between the protrusion 50 and the seal member 70 can be simplified.

In the first embodiment, the projection 50 can be formed small and thick by press-fitting the sealing member 70 into the outer peripheral wall of the projection 50 formed integrally with the end of the cylinder 11. There is an effect that deformation at the time of heat treatment can be reduced and processing of the sliding hole 11a is facilitated.
Further, the tappet 4 reciprocates with the plunger 43.
Since the members such as 1 can be reduced in size and the urging force of the compression coil spring 45 can be reduced, the physical size of the pump body 10 can be reduced.

Further, in the first embodiment, the fuel pool 54 defined by the end face of the projection 50, the outer peripheral wall of the plunger 43, and the inner wall coating 72 is a low-pressure fuel pool.
It is not necessary to form a fuel reservoir on the inner wall of the cylinder 11 forming the sliding hole 11a, so that the axial length of the cylinder can be shortened and the number of processing steps can be reduced.

Further, in the first embodiment, the return passage 18 is provided by providing the fuel reservoir 54 for low-pressure leak fuel in addition to the fuel reservoir 11b for high-pressure leak fuel.
The amount of fuel returning to the fuel tank through the return connector 19 decreases. Therefore, the amount of HC emission caused by the return fuel being heated by the radiant heat of the engine or the like can be reduced.

Further, in the first embodiment, the pump body 10 is housed in the head cover 100, and the common rail is usually arranged near the combustion chamber of the engine.
The length of the fuel steel pipe connecting the pump body 10, the common rail, and the combustion chamber can be reduced. In the first embodiment, the fuel reservoir 11b for the high-pressure leak fuel and the fuel reservoir 54 for the low-pressure leak fuel are provided. However, in the present invention, only the fuel reservoir for the low pressure may be provided. Also, the amount of leaking fuel can be reduced, and the fuel pressurizing pumping efficiency of the high-pressure fuel supply pump can be improved. As a result, the fuel efficiency of the engine can be improved. In the first embodiment, the pump body 10 is attached to the head cover 100 which is a part of the engine housing. However, in the present invention, it is possible to attach the pump body to a cylinder head which is a part of the engine housing.

(Second Embodiment) FIGS. 5 and 6 show a second embodiment of the present invention. The pump main body 80 of the high-pressure fuel supply pump has a return passage 82a formed by notching an outer wall of a projection 82 formed integrally with a cylinder 81 in an axially transverse cross-section. Fuel pool 5
Reference numeral 4 communicates with the return passage 18 via the return passage 82a. The seal member 70 is pressed into the outer wall of the projection 82 and pressed by a step 82b formed on the projection 82. This prevents the fuel from leaking from the return passage 82a or 18. In the second embodiment, the protrusion 8
By forming the return passage 82a by notching the outer wall 2 in the axial direction, the return passage 82a connecting the fuel reservoir 54 and the fuel passage 18 can be easily processed and the processing cost can be reduced as compared with the first embodiment. .

(Third Embodiment) FIGS. 7 and 8 show a third embodiment of the present invention. The pump main body 90 of the high-pressure fuel supply pump has a return passage 92a formed by notching an outer wall of a protrusion 92 formed integrally with the cylinder 91 in a groove shape in the axial direction. The fuel reservoir 54 communicates with the return passage 18 via a return passage 92a. In the third embodiment, as in the second embodiment, machining of the return passage 92a communicating with the fuel reservoir 54 is facilitated and machining cost is reduced as compared with the first embodiment.

Fourth Embodiment FIGS. 9 and 10 show a seal member according to a fourth embodiment of the present invention. In the fourth embodiment, the support member 76 of the seal member 75
The inner wall covering portion that covers the inner peripheral wall of the metal support member 76 is removed, and the inner peripheral wall of the metal support member 76 is press-fitted so as to directly contact the protrusion outer wall of the cylinder (not shown). A groove-shaped return passage 76a is formed in the inner peripheral wall of the support member 76 in the axial direction.
Fuel is discharged from a pump body (not shown) through the return passage 76a.

In the fourth embodiment, a groove for preventing the sealing member 75 from falling off is formed in the projection by removing the inner wall covering member of the sealing member 75 and press-fitting the metal supporting member 76 into the projection of the cylinder. Since there is no need to perform this, the number of processing steps is reduced. Further, the sealing member 75 can be prevented from falling off due to looseness of press-fit due to thermal expansion and deformation of the inner wall covering portion made of rubber.

Fifth Embodiment FIGS. 11 and 12 show a fifth embodiment of the present invention. Seal member 93 of pump body 105 of high-pressure fuel supply pump
Are fitted into a protrusion 92 formed integrally with the cylinder 91. The support member 94 is formed in a bottomed cylindrical shape having a circular through hole at the bottom, and a flange portion 94 a is formed at an end of the seal member 93 in the press-fitting direction. The inner wall covering portion that covers the inner peripheral wall of the support member 94 is excluded, and the support member 9
4 and the outer peripheral wall of the projection 92 form a certain clearance. Rubber ring-shaped packing 9
The sealing member 9 is sandwiched between the flange portion 94a and the cylinder 91 by the urging force of the compression coil spring 45.
3 and the cylinder 91 are sealed. Seal member 93
Are urged against the cylinder 91 by the urging force of the compression coil spring 45, and thus are prevented from falling off.

In the fifth embodiment, since the seal between the cylinder 91 and the seal member 93 is sealed by the packing 95, there is no need to press-fit the seal member 93 into the projection 92, so that the processing accuracy of the seal member in the radial direction is not required. Therefore, the number of processing steps is reduced. Further, since the sealing member 93 is prevented from falling by the urging force of the compression coil spring 45, the protrusion 9
Since it is not necessary to form a groove for preventing the seal member 93 from dropping on the outer peripheral wall of the cylinder 2, the cylinder can be easily machined.

(Sixth Embodiment) FIGS. 13 and 14 show a sixth embodiment of the present invention. Seal member 113 of pump body 110 of high-pressure fuel supply pump
Are fitted to a protrusion 112 formed integrally with the cylinder 111. The support member 114 is formed in a bottomed cylindrical shape having a circular through hole at the bottom, and a flange 114 a is formed at the end of the seal member 113 in the press-fit direction. The inner wall covering portion that covers the inner peripheral wall of the support member 114 is eliminated, and the inner peripheral wall of the support member 114 and the outer peripheral wall of the protrusion 112 form a certain clearance. A groove 114b is formed in the inner wall of the support member 114 in the axial direction. The groove 114 b communicates with the return passage 18, and discharges the fuel in the fuel reservoir 54 through the return passage 18. The rubber annular packing 95 is pressed by the flange 114 a by the urging force of the compression coil spring 45.
Between the seal member 113 and the cylinder 111. Seal member 113
Are urged against the cylinder 111 by the urging force of the compression coil spring 45, and thus are prevented from falling off.

In the sixth embodiment, the fuel discharge groove 114b is used.
Is provided on the seal member 113, and since the seal member 113 is prevented from falling by the urging force of the compression coil spring 45, the seal member 11 is provided on the outer peripheral wall of the projection 112.
Since it is not necessary to form the groove for preventing the falling of No. 3, the cylinder can be easily processed, and the number of steps for processing the cylinder 111 can be reduced. Further, by sealing the space between the cylinder 111 and the seal member 113 with the packing 95, it is not necessary to press-fit the seal member 113 into the projection 112, so that the processing accuracy in the radial direction of the seal member is not required, so that the number of processing steps is reduced.

(Seventh Embodiment) FIG. 15 shows a seventh embodiment of the present invention. The seal member 123 of the pump main body 120 of the high-pressure fuel supply pump is press-fitted into an outer wall of a protrusion 122 formed integrally with the cylinder 121. The configuration of the seal member 123 is the same as in the first embodiment. An annular high-pressure fuel reservoir 11b and a low-pressure fuel reservoir 11c are formed in the inner wall of the cylinder 121 forming the sliding hole 11a, and the fuel reservoir 11c communicates with the return passage 18 in an annular manner. I have. When the fuel accumulated in the fuel sump 11b flows in the -Z-axis direction and accumulates in the fuel sump 11c, the fuel is finally returned to the fuel tank from the return connector 19 via the return passage 18, so that the fuel is mixed into the engine oil. Never.
Further, since the pressure in the return passage 18 is equal to the atmospheric pressure, the fuel pressure in the fuel reservoir 11c is reduced. Therefore, the seal member 123 is further removed from the fuel reservoir 11c.
Even if fuel leaks to the side, since the pressure of the leaked fuel is low, no high pressure is applied to the seal member 123. Thus, even if the structure of the seal member 123 itself is simplified, it is possible to suppress the leakage of the leak fuel from the sliding portion between the seal member 123 and the plunger 43 to the tappet 41 side. In addition, the coupling structure between the seal member 123 and the protrusion 122 can be simplified.

(Eighth Embodiment) FIGS. 16 to 18 show an eighth embodiment of the present invention. The sealing member 133 of the pump body 130 of the high-pressure fuel supply pump is
It is press-fitted into the outer wall of a protrusion 132 formed integrally with the cylinder 131. As shown in FIG.
Since the inner wall covering portion that covers the inner peripheral wall of FIG.
7, the inner peripheral wall of the support member 134 and the protrusion 132
Is in direct contact with the outer peripheral wall.

For this reason, it is not necessary to provide a groove for preventing the sealing member 133 from falling off in the projection 132, so that the cylinder 1
31 processing steps are reduced. Also, a metal supporting member 1
34 is in contact with the outer wall of the projection 132,
As in the case where rubber and metal are in contact with each other, it is possible to prevent the press-fit portion from being loosened by heat.

Ninth Embodiment FIG. 19 shows a ninth embodiment of the present invention. The pump body 141 of the high-pressure fuel supply pump 140 has a pump housing 142
Is housed in In the cylinder 143, the solenoid valve 20,
A delivery valve 145 and an overflow valve 146 are attached. Cylinder 143 on pump cam 147 side
A seal member 151 having the same structure as the seal member of the first embodiment is press-fitted into the protrusion 150 of the first embodiment, and a rubber inner wall covering portion 152 is formed in a groove 15 provided on the outer peripheral wall of the cylinder 143.
It is biting into 0a. The spring seat 44 is urged by the compression coil spring 45 in the −Z-axis direction in FIG. 19 and is in contact with the inner bottom surface of the tappet 46. The head portion 43a of the plunger 43 is sandwiched between the inner bottom surface of the tappet 46 and the spring seat 44, and is urged by the spring seat 44 in the −Z-axis direction in FIG. A protection plate 47 is fixed to the bottom surface of the tappet 46 in the −Z axis direction in FIG. 19 to prevent abrasion due to sliding with the pump cam 147. The pump cam 147 rotates integrally with the camshaft 148 and drives the plunger 43 back and forth.

A suction passage 144a is formed at the fuel inlet 144, and communicates with a fuel passage 142a formed in the pump housing 142. The fuel introduced from the fuel inlet 144 is supplied to the fuel gallery 1 formed in an annular shape on the outer peripheral wall of the intake passage 144a, the fuel passage 142a, and the cylinder 143.
43, the fuel passage 143b, and the fuel gallery 143c are sucked into the fuel pressurizing chamber 149 via the electromagnetic valve 20. Ninth
In this embodiment, the amount of fuel leakage can be satisfactorily reduced by the seal member 151 press-fitted to the outer wall of the projection 150 formed on the pump cam 147 side of the cylinder 143.

(Tenth Embodiment) FIG. 20 shows a tenth embodiment of the present invention. The seal member 156 of the pump main body 155 of the high-pressure fuel supply pump is press-fitted into the outer wall of the projection 132 formed integrally with the cylinder 131. The length L from the upper end of the lip 74 of the seal member 156 to the bottom 132a of the projection 132 is
3 so that it is longer than the lift stroke
An axial length of 56 is formed.

Therefore, the plunger 43 and the cylinder 13
Even if the outer peripheral wall of the plunger 43 is slid by the sliding with the lip 1, the slid does not reach the sealing position of the lip 74. Since the outer peripheral surface of the plunger 43 in contact with the lip portion 74 is always a smooth surface without sliding scratches, it is possible to prevent the lip portion 74 from being damaged by sliding scratches generated on the outer peripheral wall of the plunger 43. Further, it is possible to prevent fuel from leaking from a space generated between the lip portion 74 and the sliding scratch.

The seal member 156 of the tenth embodiment has a structure in which the seal member 156 is mounted on the cylinder 131 by press-fitting the outer peripheral wall of the projection 132. Therefore, in the present invention, the length from the end face of the projection to the sealing position of the seal member can be easily changed by increasing or decreasing the axial length of the seal member. For example, by increasing the axial length of the seal member, By increasing the lift stroke, the pressurizing and pumping capacity of the high-pressure fuel supply pump can be easily improved.

(Eleventh Embodiment) FIG. 21 shows an eleventh embodiment of the present invention. The seal member 163 of the pump main body 160 of the high-pressure fuel supply pump is press-fitted into an outer wall of a protrusion 162 formed integrally with the cylinder 161. On the inner wall of the cylinder 161 where the sliding hole is formed, a cylindrical recess 162 is formed below the fuel reservoir 11c.
a is formed. The recess 162a forms a certain clearance with the plunger 43, and
3 is provided so as not to come into contact with the plunger 43 during the reciprocating movement of the third motor. The axial length of the seal member 163 is formed such that the length L from the upper end of the recess 162a to the upper end of the lip 74 of the seal member 163 is longer than the lift stroke of the plunger 43.

For this reason, the plunger 43 and the cylinder 16
Even if the outer peripheral wall of the plunger 43 is slid by the sliding with the lip 1, the slid does not reach the sealing position of the lip 74. Since the outer peripheral surface of the plunger 43 in contact with the lip portion 74 is always a smooth surface without sliding scratches, it is possible to prevent the lip portion 74 from being damaged by sliding scratches generated on the outer peripheral wall of the plunger 43. Further, it is possible to prevent fuel from leaking from a space generated between the lip portion 74 and the sliding scratch.

(Twelfth Embodiment) FIGS. 22 and 23 show a twelfth embodiment of the present invention. The pump body 230 of the twelfth embodiment differs from the seal member 70 of the first embodiment only in the configuration of the seal member 231, and the other parts are substantially the same and are denoted by the same reference numerals. The seal member 231 includes a support member 71, an inner wall covering portion 72, an outer wall covering portion 73, and a lip portion 232, and is press-fitted into the protrusion 50. The support member 71, the inner wall covering portion 72, the outer wall covering portion 73, and the lip portion 232 are made of rubber and are integrally formed.

The lip 232 is formed in an annular shape.
Only the upper lip 233 whose inner diameter gradually decreases in the lift direction of the plunger 43 is provided. Upper lip 233
Is elastically in contact with the outer peripheral wall of the plunger 43 at a minimum inner diameter portion 233a formed annularly on the wall surface of the upper lip 233. The fuel that has leaked from the sliding portion between the plunger 43 and the cylinder 11 into the fuel pool 54 on the front and rear wall surfaces in the axial direction of the minimum inner diameter portion 233 a further receives the tappet 41.
A predetermined angle is formed with the outer peripheral wall of the plunger 43 so as to reduce the amount of leakage to the side. For this reason, the upper lip 2
33 cannot sufficiently reduce the amount of oil leaking from the sliding portion between the tappet 41 and the tappet guide 40 to the fuel reservoir 54 through the sliding portion between the upper lip 233 and the outer peripheral wall of the plunger 43. For this reason, the oil leaking into the fuel reservoir 54 leaks into the fuel pressurizing chamber 16 from the sliding portion between the plunger 43 and the cylinder 11, or is supplied from the return passage 18 to the fuel pressurizing chamber 16 via the fuel tank. May be. The oil flowing into the fuel pressurizing chamber 16 is supplied to the injector together with the high-pressure fuel. However, in an engine of a fuel injection system in which the injector is not directly exposed in the combustion chamber, since the injector is not exposed to a high-temperature atmosphere due to the combustion of the fuel, oil mixed in the fuel is unlikely to be deposited. For this reason, even if oil is mixed in the fuel supplied to the injector, it is possible to prevent the flow path cross-sectional area of the injection hole from being reduced, so that highly accurate fuel injection amount control can be maintained. Also, since the upper lip 233 has a certain degree of oil sealing property, the lip portion 23
The amount of oil leaking from the fuel tank 2 to the fuel reservoir 54 is small, and the amount of lubricating oil in the entire engine is reduced, so that lubricity is not impaired.

In the high-pressure fuel supply pump according to the twelfth embodiment, only the amount of fuel leakage is satisfactorily reduced by the lip portion 232 having only the upper lip 233, and the amount of oil leakage cannot be sufficiently reduced. However, if the high-pressure fuel supply pump of this embodiment is applied to a fuel injection type engine in which the injector is not directly exposed in the combustion chamber, even if oil is mixed in the fuel, the oil is unlikely to deposit. In the present invention, the amount of fuel leak cannot be reduced sufficiently but the amount of oil leak can be reduced favorably by adjusting the angle formed by the axially front and rear wall surfaces of the minimum inner diameter portion formed on the upper lip with the outer peripheral wall of the plunger. It is possible to form possible lips.

(Thirteenth Embodiment) FIGS. 24 and 25 show a thirteenth embodiment of the present invention. In the pump body 240 of the thirteenth embodiment, the lip 242 of the seal member 241 is formed in the same direction as the lip 2 of the twelfth embodiment.
Other parts which are different from 32 are substantially the same and are denoted by the same reference numerals.

The lip 242 is formed in an annular shape.
The plunger 43 has a lower lip 243 whose inner diameter gradually decreases in the descending direction. The lower lip 243 elastically contacts the outer peripheral wall of the plunger 43 at the minimum inner diameter portion 243a. Oil for lubricating the sliding portion between the tappet 41 and the tappet guide 40 is provided on the lip portion 242 of the wall surface of the lower lip 243 in the axial direction of the minimum inner diameter portion 243a.
Is formed at a predetermined angle with the outer peripheral wall of the plunger 43 so as to reduce the amount of leakage from the fuel pool 54 to the fuel pool 54.
The lower lip 243 cannot sufficiently reduce the amount of fuel leaking from the fuel reservoir 54 to the tappet 41 side. However, even if the fuel leaked to the tappet 41 mixes with the oil, the fuel mixed in the oil volatilizes due to the ambient temperature in a normal engine operating state, so that the oil is diluted by the leaked fuel and the lubricity is reduced. Can be avoided.

In the thirteenth embodiment, since only the lower lip 243 is formed, it is possible to shorten the sealing member by the axial length of the upper lip of the first embodiment. For this reason, the shaft length of the whole pump main body can be shortened. In the thirteenth embodiment, the lip portion 242 having only the lower lip 243 satisfactorily reduces only the amount of oil leakage and cannot sufficiently reduce the amount of fuel leakage. By adjusting the angle formed by the front and rear wall surfaces of the plunger with the outer peripheral wall of the plunger, it is possible to form a lip portion that cannot sufficiently reduce the amount of oil leakage but can reduce the amount of fuel leakage satisfactorily.

Although the above-described embodiment has been described with respect to an example in which the present invention is applied to a high-pressure fuel supply pump for a gasoline engine, the present invention can be applied to a high-pressure fuel supply pump for a diesel engine. Further, in this embodiment, the seal member is press-fitted into the protrusion, the seal member is press-fitted into the protrusion and a groove is formed in the protrusion to prevent falling off. Although the sealing member is prevented from falling off by urging the sealing member, the sealing member can be fixed to the cylinder by, for example, a screw.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a pump body according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of the first embodiment.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a sectional view showing a state where the pump body of the first embodiment is mounted on an engine head.

FIG. 5 is a sectional view showing a pump body according to a second embodiment of the present invention.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 2;

FIG. 7 is a sectional view showing a pump body according to a third embodiment of the present invention.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9 is a sectional view illustrating a seal member according to a fourth embodiment of the present invention.

FIG. 10 is a sectional view taken along line XX of FIG. 9;

FIG. 11 is a sectional view showing a pump body according to a fifth embodiment of the present invention.

FIG. 12 is a sectional view showing a seal member of a fifth embodiment.

FIG. 13 is a sectional view showing a pump body according to a sixth embodiment of the present invention.

FIG. 14 is a sectional view showing a seal member of a sixth embodiment.

FIG. 15 is a sectional view showing a pump body according to a seventh embodiment of the present invention.

FIG. 16 is a sectional view showing a pump body according to an eighth embodiment of the present invention.

17 is a sectional view taken along line XVII-XVII in FIG.

FIG. 18 is a sectional view showing a seal member of an eighth embodiment.

FIG. 19 is a sectional view showing a high-pressure fuel supply pump according to a ninth embodiment of the present invention.

FIG. 20 is a sectional view showing a pump body according to a tenth embodiment of the present invention.

FIG. 21 is a sectional view showing a pump body according to an eleventh embodiment of the present invention.

FIG. 22 is a sectional view showing a pump body according to a twelfth embodiment of the present invention.

FIG. 23 is a sectional view showing a seal member of a twelfth embodiment.

FIG. 24 is a sectional view showing a pump body according to a thirteenth embodiment of the present invention.

FIG. 25 is a sectional view showing a seal member of a thirteenth embodiment.

FIG. 26 is a configuration diagram showing a fuel supply system using a conventional high-pressure fuel supply pump.

[Explanation of symbols]

 Reference Signs List 10 pump body 11 cylinder 12a suction passage 15 discharge passage 16 fuel pressurizing chamber 20 solenoid valve (discharge timing control valve) 30 delivery valve (discharge valve) 43 plunger 45 compression coil spring 50 protrusion 70 seal member 71 support member 74 lip (Circular member) 75 Seal member 80 Pump body 90 Pump body 93 Seal member 100 Head cover (engine housing) 100a Housing hole 101 Camshaft (Drive means) 102 Pump cam (Drive means) 105, 110, 120 Pump body 123 Seal member 130 Pump body 133 Seal member 140 High-pressure fuel supply pump 141 Pump body 151 Seal member 155 Pump body 156 Seal member 160 Pump body 162a Recessed part (non-contact part) 163 Seal member 230 Pump body 231 Seal member 240 Pump body 241 Seal member

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-56-98563 (JP, A) JP-A-7-286569 (JP, A) JP-A-2-176158 (JP, A) JP-A 5- 288133 (JP, A) JP-A-4-353262 (JP, A) JP-A-48-37516 (JP, A) JP-A-56-90469 (JP, U) JP-A-60-18263 (JP, U) 58-149568 (JP, U) JP-A-3-6058 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 59/44

Claims (9)

(57) [Claims] A cylinder for supporting a plunger reciprocally and slidably by an inner wall forming a sliding hole communicating with a fuel suction passage and a discharge passage; A discharge timing control valve that determines the discharge timing of fuel pressurized by the reciprocation of the plunger introduced into the pressure chamber from the suction passage, and reciprocates with the plunger to supply lubricating oil
A tappet, driving means for reciprocatingly driving the plunger and the tappet , and outside the cylinder in the axial direction of the plunger,
The outer peripheral wall of the plunger seals the lubricating oil and the fuel in a liquid-tight manner , and the plunger reciprocates so that
A high-pressure fuel supply pump, comprising: a seal member having an annular member that slides on a peripheral wall . 2. A fuel supply passage communicating with a fuel intake passage and a fuel discharge passage.
A cylinder having a sliding hole formed by an inner wall; and a cylinder reciprocally and slidably supported by the inner wall.
From the inlet passage into the fuel pressurization chamber, which is a part of the sliding hole.
Plunger that pressurizes the fuel by reciprocating
If, reciprocates together with the plunger, the lubricating oil is supplied
A tappet and a drive for reciprocatingly driving the plunger and the tappet
Means, outside the cylinder in the axial direction of the plunger,
The lubricating oil and fuel are sealed in a liquid-tight manner on the outer peripheral wall of the plunger.
While the plunger reciprocates,
A high-pressure fuel supply pump , comprising: a sealing member having an annular member that slides on a peripheral wall . 3. The high-pressure device according to claim 1, wherein a part of the slide hole is formed by an inner wall of a protrusion that is formed integrally with the cylinder and protrudes in an axial direction of the plunger. Fuel supply pump. 4. From the cylinder-side end of the annular member
The sea of the cylinder inner wall said plunger and sliding
4. The high-pressure fuel supply pump according to claim 1 , wherein a length to an end of the plunger is longer than a lift stroke of the plunger. 5. The axial length of a non-contact portion formed so as not to slide on the plunger on the entire circumference of the inner wall forming the sliding hole, is set at a distance from the cylinder-side end of the annular member.
The seal of the cylinder inner wall sliding with the plunger;
5. The high-pressure fuel supply pump according to claim 4, wherein the length of the high-pressure fuel supply pump is part or all of the length up to the end of the fuel member. 6. The high-pressure fuel supply pump according to claim 1, further comprising a fuel reservoir defined by the seal member, the plunger, and the cylinder. 7. A high-pressure fuel supply pump according to claim 1, wherein said annular member is made of rubber. 8. The high-pressure fuel supply pump according to claim 6, wherein the fuel reservoir communicates with a path having a pressure equal to the atmospheric pressure. 9. The fuel cell according to claim 1, wherein an annular fuel reservoir is provided on the inner wall forming the sliding hole, and the fuel reservoir communicates with a path having a pressure equal to the atmospheric pressure. 8. The high-pressure fuel supply pump according to 4, 5, or 7.