JP2010112243A - Supply pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of causing blackening of fuel, when the fuel in a tappet chamber and a lubricant of a tappet outer peripheral surface are mutually mixed in, since sealability is not sufficient between the outer peripheral surface of a tappet interposed between a plunger for compressing the fuel in a pressurizing chamber and a cam for driving the plunger and an inner peripheral surface of the tappet chamber for reciprocatably sliding the tappet, in a supply pump of a pressure accumulating fuel injection device conventionally mounted on an engine. <P>SOLUTION: A seal member 17 is arranged for sealing a clearance between an inner peripheral wall 18 of the tappet chamber 11 and the outer peripheral surface of the tappet 7. The seal member 17 is formed as a double seal structure juxtaposed by separately forming two different seal parts such as a fuel seal part 17a for mainly sealing the fuel on the pressurizing chamber 25 side and a lubricant seal part 17b for mainly sealing the lubricant on the cam 10 side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a supply pump for an accumulator fuel injection device mounted on an engine, and more particularly to a seal structure capable of preventing mutual mixing between fuel and lubricating oil in the supply pump.

  Conventionally, a supply pump has been provided in an accumulator fuel injection device mounted on an engine, and a plunger is provided in a plunger barrel so as to be slidable back and forth, and fuel is supplied between one end of the plunger and the plunger barrel. While forming the pressurizing chamber, the other end of the plunger protrudes from the plunger barrel in the opposite direction to the pressurizing chamber and can be interlocked with the tappet. The tappet is directly driven by a cam as a swing member. And a space for accommodating the plunger barrel and the plunger (hereinafter referred to as a “tuppet chamber”) so as to be reciprocally slidable, and a single unit for liquid-tight sealing between the plunger barrel and the outer peripheral surface of the plunger. One sealing member is provided in an annular shape, so that fuel leaking from the pressurizing chamber, engine oil that lubricates the swinging member and tappet, etc. Technology and Namerayu To prevent mixed with each other has become known (e.g., see Patent Document 1).

However, in this way, in the case of the seal structure in which the seal member is bridged between the plunger barrel and the outer peripheral surface of the plunger, the tappet chamber is expanded by the space for arranging the seal member, and the tappet chamber is slid back and forth by that amount. The weight of movable parts such as tappets that increase is also increased. For this reason, in order to cause the plunger to follow the cam quickly via the movable portion, it is necessary to increase the pressing force of the movable portion against the cam, and the surface pressure received by the cam also increases and the durability of the cam is increased. Decrease significantly. Therefore, in order to prevent this, the seal member is interposed between the inner peripheral wall of the tappet chamber and the outer peripheral surface of the tappet, and passes from the pressurizing chamber to the tappet chamber through the gap between the plunger and the plunger barrel. It can be considered that the leaked fuel and the lubricating oil that has entered the reciprocating sliding portion of the tappet from the cam side do not mix with each other.
JP-A-8-68370

However, unlike the plunger, the tappet is directly subjected to vibration due to the swing of the cam. Therefore, the seal member on which the outer peripheral surface of the tappet slides is required to have better sealing performance.
On the other hand, in the case of a single seal member as in the prior art, the entire seal member tries to follow the displacement of the tappet so that it can follow the displacement of the tappet that slides while vibrating (hereinafter referred to as “ Displacement followability ”is not sufficient.) The gap between the tappet and the seal member is instantaneously enlarged and fuel and lubricating oil are mixed with each other, resulting in fuel blackening and fuel injection due to incomplete combustion. There was a problem that exhaust smoke deteriorated due to carbon flower adhering to the nozzle nozzle, and lubrication performance was lowered due to dilution of the lubricating oil.
In order to improve the displacement followability, it is effective to set a portion of the seal member that contacts the tappet to be hard, but at the same time, the impact force between the tappet and the seal member also increases, and the tappet is rubbed or sealed. However, there is a problem that the wear of the parts becomes short, the life of the parts is shortened, the frequency of replacement of the parts is increased, and the maintenance cost is increased.
In addition, it is difficult to simultaneously optimize the material and structure of the seal member for fuels and lubricating oils having greatly different characteristics such as components and viscosity, and there is a problem that there is a limit to improving the sealing performance. It was.

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
That is, in claim 1, the plunger is provided in the plunger barrel so as to be reciprocally slidable, and a fuel pressurizing chamber is formed between one end of the plunger and the plunger barrel, while the other end of the plunger is The tappet protrudes from the plunger barrel in the opposite direction to the pressurizing chamber and can be interlocked with the tappet. The tappet can be slid back and forth in the tappet chamber accommodating the plunger barrel and the plunger by direct drive by a swinging member. In the supply pump, a seal member for sealing a gap between the inner peripheral wall of the tappet chamber and the outer peripheral surface of the tappet is disposed, and the seal member supplies fuel leaking from the pressurizing chamber. Two different seal parts, a fuel seal part to be sealed and a lubricant seal part to seal the lubricant from the rocking member, are formed separately. It is obtained by the arrangement for the dual seal.
According to a second aspect of the present invention, the storage portion for the seal member is provided on the inner peripheral wall of the tappet chamber, and the seal member attached to the storage portion is pressed by the plunger barrel via a sleeve that is in contact with the seal member. It has a sealing member built-in configuration to be fixed.
The seal member assembly according to claim 3, wherein a storage portion for the seal member is provided in the sleeve, a sleeve having the seal member attached to the storage portion is inserted into the tappet chamber, and the sleeve is pressed and fixed by the plunger barrel. It has a built-in configuration.
According to a fourth aspect of the present invention, a storage portion for the seal member is provided in the sleeve, a sleeve having the seal member attached to the storage portion is fixed to the plunger barrel, and the plunger barrel is inserted and fixed in the tappet chamber. It has a seal member built-in configuration.
According to a fifth aspect of the present invention, there is provided a seal member built-in configuration in which a housing portion for the seal member is provided in the plunger barrel, and a plunger barrel having a seal member attached to the housing portion is inserted and fixed in the tappet chamber. .
According to a sixth aspect of the present invention, the tappet chamber communicates with the low pressure side of the fuel supply path to the pressurizing chamber.
According to a seventh aspect of the present invention, the supply pump includes a pressure damper that reduces pressure pulsation in the tappet chamber.
According to an eighth aspect of the present invention, a breathing passage that communicates the tappet chamber with the outside is communicated between the tappet chambers.
According to a ninth aspect of the present invention, the distance between the lip of the fuel seal portion and the lip of the lubricant seal portion is set to be larger than the stroke of the plunger.
According to a tenth aspect of the present invention, the rocking member is an eccentric face type cam in which a cam ring having a flat surface portion whose outer periphery is cut out in a flat shape is externally fitted to an eccentric shaft.

Since this invention was comprised as mentioned above, there exists an effect shown below.
That is, in claim 1, the plunger is provided in the plunger barrel so as to be reciprocally slidable, and a fuel pressurizing chamber is formed between one end of the plunger and the plunger barrel, while the other end of the plunger is The tappet protrudes from the plunger barrel in the opposite direction to the pressurizing chamber and can be interlocked with the tappet. The tappet can be slid back and forth in the tappet chamber accommodating the plunger barrel and the plunger by direct drive by a swinging member. In the supply pump, a seal member for sealing a gap between the inner peripheral wall of the tappet chamber and the outer peripheral surface of the tappet is disposed, and the seal member supplies fuel leaking from the pressurizing chamber. Two different seal parts, a fuel seal part to be sealed and a lubricant seal part to seal the lubricant from the rocking member, are formed separately. Since the double seal structure is arranged, each seal part can be quickly deformed according to the displacement of each part of the tappet that the seal part contacts, and the displacement followability of the entire seal member can be improved. , The gap between the tappet and the seal member is reduced to prevent the fuel and lubricating oil from mixing with each other, and the exhaust smoke resulting from the blackening of the fuel and the carbon flower adhering to the fuel injection nozzle nozzle due to incomplete combustion The deterioration of the lubrication performance due to the deterioration of the lubricating oil and the dilution of the lubricating oil can be reliably suppressed. And even if the sealing member is not set to be stiff, sufficient displacement followability can be ensured in this way, an increase in impact force between the tappet and the sealing member is suppressed, and the tappet is scraped or worn out. It is possible to prevent deterioration of the component life due to, and reduce maintenance costs. Also, by optimizing the material and structure of the fuel seal part for the fuel and optimizing the material and structure of the lubricant seal part for the lubricant, the seal member can be optimized for both oils at the same time. Further improvement in sealing performance can be achieved.
According to a second aspect of the present invention, the storage portion for the seal member is provided on the inner peripheral wall of the tappet chamber, and the seal member attached to the storage portion is pressed by the plunger barrel via a sleeve that is in contact with the seal member. Since it has a built-in seal member assembly configuration, the seal member can be fixed and placed close to the tappet with a simple configuration without providing a separate assembly member for the seal member. It is possible to reduce maintenance and improve maintenance by simplifying the configuration.
The seal member assembly according to claim 3, wherein a storage portion for the seal member is provided in the sleeve, a sleeve having the seal member attached to the storage portion is inserted into the tappet chamber, and the sleeve is pressed and fixed by the plunger barrel. Because it has a built-in configuration, the seal member can be fixedly placed close to the tappet with a simple configuration without providing a separate assembly member for the seal member, and the component cost is reduced by reducing the number of components and simplifying the configuration. Can be reduced and maintainability can be improved. Further, the seal member can be handled integrally with the sleeve, the seal member can be easily assembled and replaced, and the assemblability can be improved.
According to a fourth aspect of the present invention, a storage portion for the seal member is provided in the sleeve, a sleeve having the seal member attached to the storage portion is fixed to the plunger barrel, and the plunger barrel is inserted and fixed in the tappet chamber. Since the seal member has a built-in configuration, the seal member can be fixedly arranged close to the tappet with a simple configuration without separately providing a built-in member for the seal member, reducing the number of parts and simplifying the configuration. This can reduce the part cost and improve the maintainability. Furthermore, the seal member can be handled integrally with the plunger barrel via the sleeve, so that the seal member can be easily assembled and replaced, and the assemblability can be improved.
In Claim 5, since it has a sealing member built-in structure which installs and fixes the plunger barrel which provided the storage part of the said seal member in the said plunger barrel, and attached the seal member to this storage part in the said tappet chamber, The seal member can be fixed and placed close to the tappet with a simple configuration without providing a separate built-in member, reducing the number of components and simplifying the configuration to reduce component costs and improve maintainability. Can be achieved. Furthermore, the seal member can be handled integrally with the plunger barrel, the seal member can be easily assembled and replaced, and the assemblability can be improved.
According to a sixth aspect of the present invention, the tappet chamber communicates with the low pressure side of the fuel supply path to the pressurization chamber, so that the high pressure leaked from the pressurization chamber side into the tappet chamber via the fuel supply path. The fuel pressure can be reduced, the load pressure on the fuel seal portion is reduced, and the life of the seal member is improved.
According to a seventh aspect of the present invention, since the supply pump includes a pressure damper that reduces pressure pulsation in the tappet chamber, the pressure damper reduces pulsation of fuel pressure in the tappet chamber caused by reciprocal sliding of the tappet. This can reduce the load pressure on the fuel seal portion and improve the life of the seal member.
In claim 8, since the breathing passage that communicates the tappet chamber with the outside is communicated between the tappet chambers, the breathing passage when the intake stroke and the pressurizing stroke of the plunger are shifted for each plunger. Thus, the pressure in the tappet chamber can be canceled out, and the load pressure on the fuel seal portion is reduced, so that the life of the seal member is improved.
According to the ninth aspect of the present invention, the distance between the lip of the fuel seal portion and the lip of the lubricant seal portion is set to be larger than the stroke of the plunger. In addition, the fuel left uncut by the lip of the fuel seal portion is prevented from leaking to the cam side of the seal member beyond the lip of the lubricant seal portion, and the lip of the lubricant seal portion. It is possible to prevent the lubricant left without being scraped off from leaking to the pressurizing chamber side beyond the seal member beyond the lip of the fuel seal portion, so that the fuel and the lubricant can be mixed with each other. This can be prevented more reliably.
In the tenth aspect of the present invention, the rocking member is an eccentric face type cam in which a cam ring having a flat portion whose outer periphery is cut out in a flat shape is externally fitted to the eccentric shaft, so that only the position of the eccentric center is changed. The displacement curve of the plunger by the cam can be freely changed, high pressure fuel with various compression ratios, compression speeds and supply amounts can be easily supplied, and a versatile supply pump with a simple structure Can be offered at. And since the flat portion is formed, the distance from the lower surface of the tappet to the eccentric center of the eccentric shaft is the shortest at the position where the tappet is in contact with the flat portion, and the stroke of the plunger can be expanded to the swing member side, The versatility can be further improved by increasing the change rate of the fuel compression rate, compression speed, and supply amount. Further, both the contact surface pressure between the tappet and the cam ring and the contact surface pressure between the cam ring and the eccentric shaft are reduced, and the durability of the tappet, cam ring, and eccentric shaft is improved.

Next, embodiments of the invention will be described.
1 is a front sectional view showing the overall configuration of the supply pump according to the first embodiment of the present invention, FIG. 2 is a side sectional view showing the entire configuration of the first pump portion at the bottom dead center, and FIG. 3 is a configuration around the tappet. FIG. 4 is a side sectional view showing the overall configuration of the first pump section according to the second embodiment, and FIG. 5 is a side sectional view showing the overall configuration of the first pump section according to the third embodiment. FIG. 6 is a side sectional view showing the overall configuration of the first pump unit according to the fourth embodiment.

First, the overall configuration of the supply pump 1 according to the first embodiment of the present invention will be described with reference to FIGS.
In the supply pump 1, plunger barrels 3 are respectively inserted into upper portions of two tappet chambers 11 formed in the casing 2 in the vertical direction, and plungers 3 are respectively inserted into lower half portions of the plunger barrels 3. 4 is provided so as to be slidable back and forth in the vertical direction, the first pump part 33 and the second pump part 34 are formed, and the compression timing of the fuel by the both pump parts 33 and 34 is 180 in phase difference. By shifting the angle, high pressure fuel can be supplied continuously.

  And the lower part of each plunger 4 protrudes below from the lower end part of the said plunger barrel 3, and is arrange | positioned so that the spring receptacle 5 may oppose the plunger barrel 3 and the plunger 4 below. In addition, since the structure of both the pump parts 33 and 34 is substantially the same, in the following description, it demonstrates centering around one 1st pump part 33, and demonstrates only the 2nd pump part 34 only when needed. .

  In the first pump portion 33, the spring receiver 5 is fitted to the lower end portion of the plunger 4 and is configured to reciprocate in the vertical direction together with the plunger 4. The upper surface of the spring receiver 5 and the plunger barrel 3, a spring 6 is interposed in a compressed state on the same axial center as the plunger 4, and the plunger 4 is moved downward via a spring receiver 5 by the elastic force of the spring 6. Is being energized.

  Further downward, a cylindrical tappet 7 opened upward is provided on the same axis as the plunger 4 so as to reciprocate in the tappet chamber 11 in the vertical direction. The spring receiver 5 is fitted in the cylindrical portion 7 a, and the tappet 7 is also urged downward together with the plunger 4 through the spring receiver 5 by the elastic force of the spring 6. As a result, the tappet 7 is interlocked with the plunger 4 and the lower surface of the tappet is always held in pressure contact with the cam ring 9 fitted on the cam shaft 8 by the elastic force of the spring 6. ing.

  The cam shaft 8 is rotatably supported at the lower portion of the casing 2 so as to be orthogonal to the axial direction of the plunger 4, and a feed pump 15 is provided on one end side of the cam shaft 8. A driving gear 13 is fixed on the other end side. Then, engine power from an unillustrated engine crankshaft is transmitted to the camshaft 8 through the drive gear 13, and the camshaft 8 is rotationally driven at high speed.

  Each cam 10 composed of the cam shaft 8 and the cam ring 9 is arranged in parallel at the position facing the tappet 7 in the casing 2 so as to have a phase difference of 180 degrees as described above. The two cams 10 and 10 are integrally rotated with the rotation of the cam shaft 8 and the rotation of each cam 10 is caused by the lower surface of each tappet 7 being pressed against each cam ring 9 as described above. Done in state. In all of the embodiments in this description, the phase difference is set to 180 degrees. However, the phase difference may be any phase difference that allows the high-pressure fuel to be continuously and stably supplied by the supply pump 1. The phase difference is not particularly limited.

  The cam shaft 8 is an eccentric shaft in which the rotation center 8a of the cam shaft 8 is deviated from the cross-sectional center 8b. When the cam shaft 8 rotates, the tappet 7 reciprocates in the vertical direction via the cam ring 9. However, the width and speed of the reciprocating motion of the tappet 7 can be freely changed by adjusting the position of the rotation center 8a in the cross section, and accordingly, the plunger 4 linked to the tappet 7 is interlocked. The width and speed of the reciprocating motion can be freely changed.

  Further, on the side of the outer peripheral curved surface of the cam ring 9 close to the rotation center 8a (hereinafter referred to as “eccentric side”), a flat portion 9a formed by cutting the outer peripheral curved surface into a flat shape is formed. When the cam shaft 8 rotates and the lower surface of the tappet 7 is in pressure contact with the flat surface portion 9a, the distance between the rotation center 8a and the lower surface of the tappet 7 is minimized.

  That is, since the swing member is an eccentric face type cam 10 in which the cam ring 9 having the flat surface portion 9a whose outer periphery is cut out in a flat shape is externally fitted to the cam shaft 8 which is an eccentric shaft, the rotation center which is the eccentric center is provided. The displacement curve of the plunger 4 by the cam 10 can be freely changed simply by changing the position 8a, and high-pressure fuel with various compression ratios, compression speeds and supply amounts can be easily supplied. The supply pump 1 excellent in performance can be provided with a simple structure. Since the flat portion 9a is formed, the distance from the lower surface of the tappet 7 to the rotation center 8a of the cam shaft 8 is shortest at the position where the tappet 7 is in contact with the flat portion 9a. And the versatility can be further enhanced by increasing the change rate of the fuel compression rate, the fuel compression rate, the compression speed, and the supply amount. Further, both the contact surface pressure between the tappet 7 and the cam ring 9 and the contact surface pressure between the cam ring 9 and the cam shaft 8 are reduced, and the durability of the tappet 7, the cam ring 9 and the cam shaft 8 is improved.

  Further, in the upper part of the plunger barrel 3, a suction side check valve 21, a discharge side check valve 22, and a joint 23 are arranged on the same axis as the plunger 4, and are sequentially upward from the plunger 4 side. It is arranged toward. Among these members, the uppermost joint 23 protrudes upward from the plunger barrel 3.

  On the other hand, a pressurizing chamber 25 is formed between the plunger barrel 3 and the plunger 4 below the suction side check valve 21 at the lowest position. The pressurizing chamber 25 is connected to a fuel tank (not shown) from a fuel supply path 31 formed in the casing 2, the plunger barrel 3 and the like via a fuel inlet 43, and is connected to the joint 23 and the fuel tank 23. A pressure accumulating chamber (not shown) is communicated with a fuel discharge passage 32 formed by a pipe or the like.

  In the fuel supply path 31, the feed pump 15 and the suction side check valve 21 are provided on the way, and the fuel flowing in from the fuel suction port 43 is pumped by the feed pump 15 and sucked. The fuel is introduced into the pressurizing chamber 25 from the fuel path 41 via the side check valve 21. Further, the discharge side check valve 22 is provided in the fuel discharge oil passage 32, and the fuel whose pressure is increased in the pressurization chamber 25 passes through the discharge side check valve 22 from the pressurization chamber 25. And discharged to the pressure accumulating chamber.

  In such a configuration, when the cam shaft 8 is rotated, the feed pump 15 linked to the cam shaft 8 is driven, and the cam ring 9 fitted on the cam shaft 8 is rotated. The tappet 7 is reciprocated by the cam ring 9, and the plunger 4 is also reciprocated via the spring receiver 5 fitted to the tappet 7, and by this reciprocation, the fuel suction process into the pressurizing chamber 25 is performed. The fuel discharge process from the pressurizing chamber 25 is alternately performed.

  That is, in the suction stroke, the plunger 4 is urged downward by the urging force of the spring 6 and is lowered from the top dead center 35 as shown in the first pump portion 33 of FIG. As described above, the fuel is sucked into the pressurizing chamber 25 via the suction-side check valve 21 and the like. In the discharge stroke, when the plunger 4 is pushed up by the cam 10 against the biasing force of the spring 6 and rises from the bottom dead center 36 as shown in the second pump portion 34 of FIG. The sucked fuel is pressurized and, as described above, is pumped to the pressure accumulating chamber via the discharge side check valve 22 and the like.

Next, the infiltration state of the fuel and the lubricating oil in the supply pump 1 and the seal structure capable of preventing mutual mixing between the both oils will be described with reference to FIGS.
In the supply pump 1, a space (hereinafter referred to as “spring chamber”) 11 a in which the spring receiver 5 and the spring 6 are accommodated between the inside of the cylindrical portion 7 a of the tappet 7 and the lower surface of the plunger barrel 3. The fuel leaking from the pressurizing chamber 25 through the gap between the plunger 4 and the plunger barrel 3 flows into and accumulates therein.

  On the other hand, at the lower part of the casing 2, ball bearings 12 such as bearings, thrust plates 14a and 14b, thrust metals 16a and 16b are provided. The ball bearings 12, thrust plates 14a and 14b, thrust metals 16a and 16b are provided. The camshaft 8 is rotatably supported by the casing 2 through the like. Lubricating oil is supplied to the gaps between the ball bearings 12, the thrust plates 14 a and 14 b, the thrust metals 16 a and 16 b and the cam shaft 8 from the outside through a pipe (not shown) and the like. Is also supplied to the clearance between the bottom surface of the tappet 7 and the outer peripheral surface of the cam ring 9 and the clearance between the outer peripheral surface of the tappet 7 and the inner peripheral wall 18 of the tappet chamber 11.

  The seal member 17 according to the present invention is directly attached to the inner peripheral wall 18 of the tappet chamber 11 corresponding to the position where the fuel in the spring chamber 11a and the lubricating oil on the outer peripheral surface of the tappet 7 are mixed with each other. Yes. The inner peripheral wall 18 includes an inner wall 18a having the same diameter as the tappet 7 and an outer wall 18b having a diameter larger than the inner wall 18a and into which the plunger barrel 3 is inserted. The seal member 17 is housed in a step portion 18c between the outer wall 18b and the inner wall 18a.

  The seal member 17 includes a fuel seal portion 17a that seals fuel from the spring chamber 11a, and a lubricant seal portion 17b that seals lubricant oil from the outer peripheral surface of the tappet 7. The fuel seal portion The double seal structure 17a and the lubricant seal portion 17b have the same thickness as the stepped portion 18c, are formed separately from each other, and are arranged in parallel on the stepped portion 18c from the top. Is configured.

  The fuel seal portion 17a includes a plurality of support members 26a, 26b, and 26c, and a lip member 27 whose shape is held by the support members 26a, 26b, and 26c. The lip member 27 is made of rubber or the like. The ring-shaped upper lip 27a protrudes inwardly from the inside of the lip member 27, and the upper lip 27a is always in contact with the outer peripheral surface of the tappet 7 with elastic force. I have to.

  Further, an oil reservoir 17c surrounded by the support members 26a, 26b and 26c, the lip member 27, and a lower surface of a sleeve 19 which will be described later is formed in the fuel seal portion 17a. The oil reservoir 17c is formed by the upper lip. An opening 17e is opened at a position above 27a.

  Similarly, the lubricating oil seal portion 17b includes a plurality of support members 28a, 28b, and 28c and a lip member 29 whose shape is held by the support members 28a, 28b, and 28c. The ring-shaped lower lip 29a protrudes on the inner side of the lip member 29, and the lower lip 29a is always in contact with the outer peripheral surface of the tappet 7 with an elastic force. I am doing so.

  Further, similarly to the lubricating oil seal portion 17b, an oil reservoir 17d surrounded by the support members 28a, 28b and 28c, the lip member 29, and the upper surface of the stepped portion 18c is formed. An opening 17f opens at a position below the lower lip 29a.

  The ring-shaped sleeve 19 is further placed on the upper portion of the seal member 17 formed by arranging the fuel seal portion 17a and the lubricant seal portion 17b side by side. The sleeve 19 is formed to have the same depth as the stepped portion 18 c and the same thickness as the seal member 17, and the tappet 7 has an inner wall 18 a formed flush with the tappet chamber 11, the seal member 17, and the sleeve 19. It is possible to smoothly reciprocate in the vertical direction on the inner side surface.

  Further, the sleeve 19 is always pressed to the seal member 17 side by the plunger barrel 3 inserted into the tappet chamber 11, whereby the seal member 17 is pressed against the outer wall 18 b and the stepped portion 18 c. And the sleeve 19 can be fixed in a sandwiched state.

  In the configuration as described above, when the tappet 7 is stopped, the upper and lower lip members 27 and 29 of the seal member 17 are fitted on the outer peripheral surface of the tappet 7 and are sandwiched by the upper and lower lips 27a and 29a ( Hereinafter, it is referred to as a “seal area”.

  When the tappet 7 is lowered in this state, the fuel adhering to the outer peripheral surface of the tappet 7 located on the pressurizing chamber 25 side above the seal region 40 becomes the upper lip 27a of the fuel seal portion 17a. And is discharged from the opening 17e to the oil reservoir 17c, thereby reducing fuel leakage to the cam 10 side. Conversely, when the tappet 7 is raised, the lubricating oil adhering to the outer peripheral surface of the tappet 7 located on the cam 10 side below the seal area 40 is scraped off by the lower lip 29a of the lubricating oil seal portion 17b, The oil is discharged from the opening 17f to the oil reservoir 17d, and the leakage of the lubricating oil to the tappet chamber 11 side, that is, the leakage of the lubricating oil to the pressurizing chamber 25 side is reduced.

  When the fuel discharged into the oil reservoir 17c is filled, the tappet 7 is lowered, the upper end 7b is lowered, and the oil reservoir 17c is opened into the spring chamber 11a. Returned to On the other hand, the oil reservoir 17d is connected to an oil passage 2a which is perforated in the vertical direction by the step portion 18c. The oil passage 2a is connected to the outer peripheral surface of the cam ring 9 of each cam 10 of the adjacent pump portions 33 and 34. The lubricating oil that is connected to the oil passage 2b that communicates with each other and is discharged to the oil reservoir 17d is re-supplied from the oil passages 2a and 2a to the respective lubricating portions through the oil passage 2b.

  Further, since the upper lip 27a and the lower lip 29a are respectively supported by separate fuel seal portions 17a and lubricating oil seal portions 17b, the tappet 7 which is in direct contact with the swinging cam 10 and vibrates greatly. The upper lip 27a and the lower lip 29a can be freely expanded and contracted without being influenced by the other, and can quickly follow the displacement.

  In addition, the fuel seal portion 17a mainly comes into contact only with the fuel in the spring chamber 11a and the oil reservoir 17c, and the lubricant seal portion 17b mainly includes the lubricant oil in the outer peripheral surface of the tappet 7 and the oil reservoir 17d. However, since the fuel seal portion 17a and the lubricating oil seal portion 17b are configured separately, the material of the seal portions 17a and 17b, particularly the lip members 27 and 29, as necessary. And the structure can be configured to be suitable for fuel and lubricating oil, respectively.

  That is, the plunger 4 is provided in the plunger barrel 3 so as to be reciprocally slidable, and a fuel pressurizing chamber 25 is formed between one end of the plunger 4 and the plunger barrel 3, while the other end of the plunger 4 is It protrudes from the plunger barrel 3 in the direction opposite to the pressurizing chamber 25 and is configured to be interlocked with the tappet 7. The tappet 7 accommodates the plunger barrel 3 and the plunger 4 by direct drive by the cam 10 which is a swinging member. In the supply pump 1 capable of reciprocating and sliding inside the tappet chamber 11, a sealing member 17 is provided for sealing a gap between the inner peripheral wall 18 of the tappet chamber 11 and the outer peripheral surface of the tappet 7. In addition, the seal member 17 seals the fuel seal portion 17a for sealing the fuel leaking from the pressurizing chamber 25 and the lubricating oil from the cam 10. Since the double seal structure in which two kinds of different seal parts called oil lubrication seal parts 17b are formed separately and arranged side by side is provided, the tappets 7a and 17b are in contact with the seal parts 17a and 17b. Can be quickly deformed in accordance with the displacement of each part of the seal member 17 to improve the displacement followability of the seal member 17 as a whole, and the gap between the tappet 7 and the seal member 17 can be reduced to mix fuel and lubricating oil with each other. To prevent blackening of the fuel, deterioration of exhaust smoke due to carbon flower adhering to the nozzle part of the fuel injection nozzle due to incomplete combustion, and reduction of lubrication performance due to dilution of lubricating oil. Can do.

  Even if the seal member 17 is not set to be hard, sufficient displacement followability can be ensured in this way, and an increase in impact force between the tappet 7 and the seal member 17 can be suppressed, and the tappet 7 can be scratched. It is possible to prevent deterioration of the component life due to wear of the seal member 17 and to reduce maintenance costs. Further, the material and structure of the fuel seal portion 17a are optimized for the fuel, and the material and structure of the lubricant seal portion 17b are optimized for the lubricating oil, so that the seal member 17 is simultaneously optimized for both oils. Thus, the sealing performance can be further improved.

  Further, a step portion 18 c is provided on the inner peripheral wall 18 of the tappet chamber 11 as a storage portion for the seal member 17, and the seal member 17 attached to the step portion 18 c is interposed via a sleeve 19 that is in contact with the seal member 17. Thus, the seal member 17 has a built-in seal member structure that is pressed and fixed by the plunger barrel 3. Therefore, the seal member 17 is fixedly disposed in the vicinity of the tappet 7 with a simple structure without separately providing a built-in member for the seal member 17. Therefore, the cost of parts can be reduced by reducing the number of parts, and the maintainability can be improved by simplifying the configuration.

  A distance 42 between the upper lip 27 a and the lower lip 29 a (hereinafter referred to as “distance between lips”) 42 indicates a distance between the top dead center 35 and the bottom dead center 36 of the plunger 4. It is set to be larger than the stroke 37.

  Here, as described above, when the tappet 7 is lowered, the fuel adhering to the outer peripheral surface is scraped off by the upper lip 27a, and when the tappet 7 is lifted, the lubricating oil adhering to the outer peripheral surface is scraped off by the lower lip 29a. Therefore, neither fuel nor lubricating oil can enter the seal area 40 sandwiched between the upper and lower lips 27a and 29a.

  However, if the sealing performance of the upper and lower lips 27a and 29a is reduced due to long-term operation of the supply pump 1 or deterioration due to the life of the seal member 17, the upper lip 27a is not completely scraped off. The remaining fuel enters the seal area 40, and further leaks to the cam 10 side beyond the seal area 40. Similarly, in the case of the lower lip 29a, the lubricating oil left without being completely scraped off enters the seal region 40, or further exceeds the inside of the seal region 40, the tappet chamber 11 side, That is, it leaks to the pressurizing chamber 25 side.

  On the other hand, when the distance 42 between the lips is set larger than the stroke 37 as in this embodiment, the fuel left by the upper lip 27a and the lubricating oil left by the lower lip 29a are not changed. However, it is possible to prevent the fuel and the lubricating oil from leaking to the pressurizing chamber 25 side and the cam 10 side because it can be kept only in the seal region 40 and cannot move to the outside from the seal region 40.

  That is, the inter-lip distance 42 between the upper lip 27a that is the lip of the fuel seal portion 17a and the lower lip 29a that is the lip of the lubricant seal portion 17b is set to be larger than the stroke 37 of the plunger 4. When the tappet 7 slides back and forth on the side surface of the seal member 17, the fuel left without being scraped off by the upper lip 27a of the fuel seal portion 17a exceeds the lower lip 29a which is the lip of the lubricant seal portion 17b. The leakage of the seal member 17 to the cam 10 side is suppressed, and the lubricant oil left uncut by the lower lip 29a of the lubricant seal portion 17b exceeds the upper lip 27a of the fuel seal portion 17a. Leakage to the pressurizing chamber 25 side from the seal member 17 can be suppressed, and fuel and lubricating oil can be further mixed with each other. It is possible to really prevent.

  Further, breathing passages 19a to 19e for communicating the tappet chamber 11 with the outside through the passage 2e and the like are perforated at a substantially central position in the vertical direction of the sleeve 19. The breathing passages 19a to 19e are provided for breathing the tappet chamber 11, and the breathing passage 19a perforated on the feed pump 15 side by the first pump portion 33 is connected to the breathing passage 19a. The fuel supply path 31 is connected to a path 31a on the upper side via a communication path 2c that is coaxially perforated in the casing 2.

  The path 31a is interposed between the fuel suction port 43 and the feed pump 15, and has a lower pressure than the path 31b after the fuel is pressurized using the feed pump 15. The tappet chamber 11 can be connected from the breathing passage 19a to the low pressure passage 31a via the communication passage 2c, and the high pressure fuel leaking into the tappet chamber 11 can be effectively released.

  That is, since the tappet chamber 11 communicates with the path 31a on the low pressure side of the fuel supply path 31 to the pressurizing chamber 25, the tappet chamber 11 enters the tappet chamber 11 from the pressurizing chamber 25 side via the path 31a. The leaked high-pressure fuel pressure can be reduced, the load pressure on the fuel seal portion 17a is lowered, and the life of the seal member 17 is improved.

  Further, among the breathing passages 19a to 19e, a passage 2d is provided between the adjacent breathing passages 19b and 19c, and the first passageway 19b, the passage 2d, and the breathing passage 19c are connected to the first passageway 19d. The tappet chamber 11 of the pump unit 33 and the tappet chamber 11 of the second pump unit 34 are communicated with each other.

  For this reason, the phases of both plungers 4 in the first pump portion 33 and the second pump portion 34 are shifted by 180 degrees, and in the tappet chamber 11 on the suction stroke side, the tappet 7 is lowered together with the plunger 4, and the spring chamber 11a While the volume is increased and the pressure is reduced, in the tappet chamber 11 on the discharge stroke side, the tappet 7 rises together with the plunger 4, and the volume of the spring chamber 11a decreases and the pressure is increased. The tappet chambers 11 and 11 can always be in communication with each other via the breathing passage 19b, the passage 2d, and the breathing passage 19c, so that the pressures in the both tappet chambers 11 and 11 can be offset.

  The pressure canceling effect is not only the case where the two pump parts 33 and 34 are provided and the phase difference is 180 degrees as in this embodiment, but the phase difference is provided by providing three or more pump parts. Even when the angle is set to 180 degrees or less, it is very effective in terms of alleviating pressure fluctuations in both the tappet chambers 11.

  That is, since the breathing passages 19b and 19c communicating the tappet chamber 11 with the outside are communicated between the tappet chambers 11 and 11, the fuel suction stroke and the pressurization stroke by the plunger 4 are shifted for each plunger 4. Furthermore, the pressure in the tappet chambers 11 and 11 can be offset through the breathing passages 19b and 19c, the load pressure on the fuel seal portion 17a is reduced, and the life of the seal member 17 is improved.

  A pressure damper 24 shown in FIG. 2 is provided on the side of the sleeve 19 in the casing 2. The pressure damper 24 includes a pressure receiving case 24a communicating with the tappet chamber 11 through a breathing passage 19e and a passage 2f. The pressure receiving case 24a is housed in the recess 2g of the casing 2 and is closed by the lid 30. The spring 24b is constantly urged toward the tappet chamber 11 side, and when receiving a pressure higher than a predetermined value from the inside of the tappet chamber 11 through the breathing passage 19e and the passage 2f, the pressure receiving case 24a moves outward and receives the pressure. The configuration is such that the pulsation of the fuel pressure in the tappet chamber 11 is reduced by increasing the volume of the portion.

  That is, the supply pump 1 is provided with a pressure damper 24 that reduces the pressure pulsation of the tappet chamber 11, so that the pulsation of the fuel pressure in the tappet chamber 11 caused by the reciprocating sliding of the tappet 7 is caused by the pressure damper 24. The load pressure on the fuel seal portion 17a is reduced, and the life of the seal member 17 is improved.

Next, the built-in configuration of the seal member 17 in the supply pump 1A of the second embodiment will be described with reference to FIG.
Unlike the supply pump 1 in which the seal member 17 is directly attached to the inner peripheral wall 18 of the tappet chamber 11, the supply pump 1 </ b> A has the seal member 17 attached in advance to the sleeve 44 in the tappet chamber 11.

  The sleeve 44 is formed with a concave storage portion 44a that opens toward the tappet chamber 11 in the lower half thereof, and the seal member 17 is attached to the storage portion 44a. The attached sleeve 44 is fitted into the stepped portion 18c.

  The sleeve 44 is always pressed to the cam 10 side by the plunger barrel 3 inserted into the tappet chamber 11, so that the sleeve 44 can be moved without changing the existing configuration. It can be fixed in a state of being sandwiched between the outer wall 18b or the stepped portion 18c and the plunger barrel 3.

  That is, the storage portion 44 a of the seal member 17 is provided in the sleeve 44, the sleeve 44 with the seal member 17 attached to the storage portion 44 a is inserted into the tappet 11 chamber, and the sleeve 44 is pressed by the plunger barrel 3. Since the sealing member assembly structure to be fixed is provided, the sealing member 17 can be fixedly disposed in the vicinity of the tappet 7 with a simple structure without separately providing an assembly member for the sealing member 17, and the number of parts can be reduced. In addition, it is possible to reduce the component cost and improve the maintainability by simplifying the configuration. Furthermore, the seal member 17 can be handled integrally with the sleeve 44, the seal member 17 can be easily assembled and replaced, and the assemblability can be improved.

Next, the built-in configuration of the seal member 17 in the supply pump 1B of the third embodiment will be described with reference to FIG.
The supply pump 1B has a sleeve 44, to which the seal member 17 is integrally attached, like the supply pump 1A, fixed in advance to the plunger barrel 3.

  Similar to the supply pump 1A, the sleeve 44 is formed with a concave storage portion 44a. The seal member 17 is attached to the storage portion 44a, and the sleeve 44 to which the seal member 17 is integrally attached is provided. The side surface of the plunger barrel 3 is fixed by screwing or adhesive.

  Then, by inserting the plunger barrel 3 to which the sleeve 44 having the seal member 17 is fixed into the tappet chamber 11, the sleeve 44 is always pressed toward the cam 10, thereby greatly changing the existing configuration. Without this, the sleeve 44 can be fixed while being sandwiched between the outer wall 18b or the stepped portion 18c and the plunger barrel 3.

  That is, the storage portion 44a of the seal member 17 is provided in the sleeve 44, the sleeve 44 having the seal member 17 attached to the storage portion 44a is fixed to the plunger barrel 3, and the plunger barrel 3 is connected to the tappet chamber 11. The seal member 17 has a built-in configuration for inserting and fixing to the tappet 7, so that the seal member 17 can be fixedly arranged in the vicinity of the tappet 7 with a simple configuration without separately providing a built-in member for the seal member 17. By reducing the number of points and simplifying the configuration, it is possible to reduce component costs and improve maintainability. Furthermore, the seal member 17 can be handled integrally with the plunger barrel 3 via the sleeve 44, the seal member 17 can be easily assembled and replaced, and the assemblability can be improved.

Next, an assembly configuration of the seal member 17 in the supply pump 1C of the fourth embodiment will be described with reference to FIG.
The supply pump 1C is different from the supply pumps 1A and 1B in which the seal member 17 is attached to the sleeve 44, and the seal member 17 is attached to the plunger barrel 45 in advance.

  The plunger barrel 45 is formed in a cylindrical shape whose lower half is opened downward, and a concave storage portion 45b opened on the side of the tappet chamber 11 is formed in the cylindrical portion 45a, and the storage portion 45b The seal member 17 is attached.

  And by inserting and fitting the plunger barrel 45 provided with the seal member 17 into the tappet chamber 11, the seal member 17 is always pressed to the cam 10 side, so that the existing configuration is not greatly changed. The seal member 17 can be fixed while being sandwiched between the stepped portion 18c and the plunger barrel 3.

  That is, the storage portion 45 b of the seal member 17 is provided in the plunger barrel 45, and the plunger barrel 45 having the seal member 17 attached to the storage portion 45 b is inserted and fixed in the tappet chamber 11. Therefore, the seal member 17 can be fixedly arranged in the vicinity of the tappet 7 with a simple configuration without separately providing an assembly member for the seal member 17, and the cost of components can be reduced by reducing the number of components and simplifying the configuration. Reduction and maintenance can be improved. Furthermore, the seal member 17 can be handled integrally with the plunger barrel 45, the seal member 17 can be easily assembled and replaced, and the assemblability can be improved.

  In the present invention, a plunger is provided in a plunger barrel so as to be reciprocally slidable, and a fuel pressurization chamber is formed between one end of the plunger and the plunger barrel, while the other end of the plunger is the pressurization chamber. All supplies that protrude from the plunger barrel in the opposite direction and can be interlocked with the tappet, and that can be reciprocally slidable in the tappet chamber containing the plunger barrel and the plunger by direct drive by a swinging member. Can be applied to pumps.

It is front sectional drawing which shows the whole structure of the supply pump concerning the 1st Example of this invention. It is side surface sectional drawing which shows the whole structure of the 1st pump part in a bottom dead center. It is a front expanded sectional view which shows the structure around a tappet. It is side surface sectional drawing which shows the whole structure of the 1st pump part concerning a 2nd Example. It is side surface sectional drawing which shows the whole structure of the 1st pump part concerning a 3rd Example. It is side surface sectional drawing which shows the whole structure of the 1st pump part concerning a 4th Example.

Explanation of symbols

1, 1A, 1B, 1C Supply pump 3.45 Plunger barrel 4 Plunger 7 Tappet 8 Cam shaft (eccentric shaft)
9a Plane part 10 Oscillating member / cam
11 Tappet chamber 17 Seal member 17a Fuel seal part 17b Lubricating oil seal part 18 Inner peripheral wall 18c Step part (housing part)
19, 44 Sleeve 19a, 19b, 19c, 19d, 19e Breathing passage 24 Pressure damper 25 Pressurizing chamber 27a Upper lip (lip of fuel seal part)
29a Lower lip (lip of lubricating oil seal)
31 Fuel supply path 31a path (low pressure side of fuel supply path)
37 Stroke 42 Distance between lips 44a / 45b Storage section

Claims (10)

  A plunger is slidably provided in the plunger barrel, and a fuel pressurizing chamber is formed between one end of the plunger and the plunger barrel, while the other end of the plunger is opposite to the pressurizing chamber. A supply pump that protrudes from the plunger barrel and can be interlocked with the tappet. A seal member for sealing a gap between the inner peripheral wall and the outer peripheral surface of the tappet is disposed, and the seal member includes a fuel seal portion for sealing fuel leaking from the pressurizing chamber; A double seal structure in which two different seal portions, namely, a lubricant seal portion for sealing the lubricant from the rocking member, are formed separately and arranged side by side. Supply pump, wherein the door.   A seal member built-in unit in which a storage portion for the seal member is provided on the inner peripheral wall of the tappet chamber, and the seal member attached to the storage portion is pressed and fixed by the plunger barrel via a sleeve abutted against the seal member. The supply pump according to claim 1, wherein the supply pump has a configuration.   The seal member housing portion is provided in the sleeve, the sleeve having the seal member attached to the housing portion is inserted into the tappet chamber, and the sleeve is pressed and fixed by the plunger barrel. The supply pump according to claim 1, wherein   A seal member built-in configuration in which a housing portion for the seal member is provided in a sleeve, a sleeve having a seal member attached to the housing portion is fixed to the plunger barrel, and the plunger barrel is inserted and fixed in the tappet chamber. The supply pump according to claim 1, wherein the supply pump is provided.   2. The seal member according to claim 1, further comprising: a seal member built-in configuration in which a housing portion for the seal member is provided in the plunger barrel, and a plunger barrel having a seal member attached to the housing portion is inserted and fixed in the tappet chamber. The listed supply pump.   6. The supply pump according to claim 1, wherein the tappet chamber communicates with a low pressure side of a fuel supply path to the pressurizing chamber.   The supply pump according to any one of claims 1 to 6, wherein the supply pump includes a pressure damper that reduces pressure pulsation in the tappet chamber.   The supply pump according to any one of claims 1 to 7, wherein a breathing passage communicating the tappet chamber to the outside is communicated between the tappet chambers.   9. The distance between the lip of the fuel seal portion and the lip of the lubricant seal portion is set to be greater than the stroke of the plunger. 10. Supply pump as described in.   10. The eccentric member of any one of claims 1 to 9, wherein the swinging member is an eccentric face type cam in which a cam ring having a flat surface portion whose outer periphery is cut into a flat shape is externally fitted to an eccentric shaft. The supply pump according to one item.

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