JP2009287529A - High-pressure fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-pressure fuel pump provided with a radial bearing portion having high lubricity. <P>SOLUTION: This high-pressure fuel pump 1 includes a pump shaft 2 rotatively driven by the drive shaft 81 of an engine 8, a cylinder 42, a plunger 41, and a pressurizing chamber 43 sectionally formed by the cylinder 42 and plunger 41. The pump shaft 2 has a long pump shaft body 21 rotatively driven by the drive shaft 81 of the engine 8, and a cam portion 22 and a polygon ring 23 respectively driven by the rotation of the pump shaft body 21 and reciprocating the plunger 41. The radial bearing portion 33 with which the outer peripheral surface of the pump shaft body 21 is made to slidably contact and radially supporting the pump shaft body 21 is formed in a housing 3. Engine oil circulating in the engine oil passage of the engine 8 is supplied to the radial bearing portion 33. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high-pressure fuel pump. Specifically, the present invention relates to a high-pressure fuel pump that supplies fuel to an injector of an engine.

  A fuel supply system in a multi-cylinder diesel engine is pressurized by a low pressure fuel pump that pumps fuel stored in a fuel tank, a high pressure fuel pump that pressurizes fuel pumped by the low pressure fuel pump, and a high pressure fuel pump. And a common rail that supplies the fuel to an injector provided for each cylinder of the engine.

  Among them, the high-pressure fuel pump is a pump shaft provided with a cam mechanism, a housing that rotatably supports the pump shaft, a cylinder radially disposed around the rotation shaft of the pump shaft, and a reciprocating motion inside the cylinder. And a plunger accommodated therein. In this high pressure fuel pump, the fuel in the pressurizing chamber formed in the cylinder is pressurized by rotationally driving the pump shaft and reciprocating the plunger.

  Here, the pump shaft is rotationally driven at a high speed using, for example, an engine camshaft as a drive source. For this reason, a large sliding surface pressure is applied to the radial bearing portion of the housing in which the outer peripheral surface of the pump shaft is in sliding contact and supports the pump shaft in the radial direction. Thus, for example, Patent Document 1 discloses a high-pressure fuel pump that diverts light oil used as engine fuel as lubricating oil and supplies this lubricant to the radial bearing portion in order to reduce the burden on the radial bearing portion. ing. However, although light oil has lubricity compared to gasoline, the lubricity is deteriorated in an environment exceeding 90 ° C., for example. For this reason, the radial bearing part may require a dedicated part in which a solid lubricant is blended.

On the other hand, Patent Document 2 discloses that engine oil having higher lubricity than light oil is used as lubricating oil in a connecting portion between a pump shaft of a high-pressure fuel pump and a camshaft as a drive source of the pump shaft. Has been. Specifically, in this high-pressure fuel pump, one end side of the pump shaft and one end side of the camshaft are connected by Oldham coupling, and engine oil is sprayed from one end side of the camshaft toward the pump shaft side. Forms an oil jet.
JP 2003-172231 A JP 2001-263025 A

  However, in the high-pressure fuel pump disclosed in Patent Document 2, engine oil is supplied only to the front end side of the pump shaft exposed from the housing. Therefore, it is difficult to improve the lubricity of the radial bearing portion formed in the housing and having a high sliding surface pressure as described above.

  The present invention has been made in consideration of the above-described points, and an object thereof is to provide a high-pressure fuel pump including a radial bearing portion with high lubricity.

  The present invention is a high-pressure fuel pump (for example, a high-pressure fuel pump 1 to be described later) for supplying fuel to a fuel injection valve of an internal combustion engine (for example, an engine 8 or 8A to be described later) at a high pressure. A housing 3), a pump shaft (for example, a pump shaft 2 described later) that is rotationally driven by a drive source of the internal combustion engine, and cylinders (for example, a cylinder 42 described later) arranged radially around the rotation axis of the pump shaft. ), A plunger (for example, a plunger 41 described later) housed in the cylinder so as to be reciprocally movable, and a pressure chamber (for example, a pressure chamber 43 described later) defined by the cylinder and the plunger. And a biasing mechanism that biases the end of the plunger on the pump shaft side toward the pump shaft (for example, a spring described later) 4), and the pump shaft is driven by the rotation of the elongate pump shaft main body (for example, pump shaft main body 21 described later) rotated by the drive source, and the pump shaft main body, A driving force transmitting member (for example, a cam portion 22, a polygon ring 23, and a bush 24, which will be described later) that reciprocates the plunger by transmitting the driving force of the pump shaft main body to the plunger; Is formed with a radial bearing portion (for example, a radial bearing portion 33 to be described later) that slidably contacts the outer peripheral surface of the pump shaft main body and supports the pump shaft main body in the radial direction. The radial bearing portion includes the internal combustion engine. Lubricating oil (for example, engine oil described later) flowing through the lubricating oil path (for example, engine oil path described later) is supplied. And wherein the door.

  According to the present invention, in the high pressure fuel pump that reciprocates the plunger by rotating the pump shaft and pressurizes the fuel in the pressurizing chamber inside the cylinder, the radial that supports the pump shaft main body radially in the housing. A bearing portion was formed, and lubricating oil flowing through the lubricating oil passage of the internal combustion engine was supplied to the radial bearing portion. As described above, the lubricity of the radial bearing portion can be improved by supplying the lubricating oil of the internal combustion engine to the radial bearing portion having a particularly high sliding surface pressure and a large load. That is, it is possible to reduce drive friction generated at the sliding contact portion between the pump shaft and the radial bearing portion and to prevent seizure of the pump shaft.

  In this case, a drive shaft (for example, drive shafts 81 and 81A described later) is used as a drive source of the internal combustion engine, and one end surface of the pump shaft is provided to face one end surface of the drive shaft. Inside, a drive shaft lubricant passage (for example, drive shaft passages 846 and 846A described later) having one end opened on the end surface on the pump shaft side and the other end communicated with the lubricant passage of the internal combustion engine is formed. In the pump shaft, a pump shaft lubricating oil passage (for example, a pump shaft passage 26 to be described later) having one end opened to the end surface on the drive shaft side and the other end communicating with the radial bearing portion is perforated. Preferably, the lubricating oil is supplied from the drive shaft lubricating oil passage to the pump shaft lubricating oil passage.

According to this invention, the lubricating oil flowing through the lubricating oil passage of the internal combustion engine flows through the driving shaft lubricating oil passage formed in the driving shaft, and the pump shaft lubricating formed in the pump shaft facing the driving shaft. Supplied to the oil passage. Further, the lubricating oil supplied to the pump shaft lubricating oil passage flows through the pump shaft lubricating oil passage and is supplied to the radial bearing portion.
Thus, the passage for supplying the lubricating oil to the radial bearing portion is formed in the pump shaft and the drive shaft that rotationally drives the pump shaft. For this reason, since it is not necessary to form an extra passage for introducing the lubricating oil flowing through the lubricating oil passage of the internal combustion engine into the housing of the high-pressure fuel pump, the high-pressure fuel pump can be reduced in size.

  In this case, in at least one of the drive shaft lubricating oil passage and the pump shaft lubricating oil passage, a cylindrical passage member (for example, an oil introduction pipe described later) extending from one passage to the other passage side is provided. 28) is preferably provided.

  According to the present invention, the cylindrical passage member extending from one passage to the other passage is provided in at least one of the drive shaft lubricant passage and the pump shaft lubricant passage. As a result, a stable amount of lubricating oil can be supplied from the drive shaft lubricating oil passage to the pump shaft lubricating oil passage.

  In this case, the drive shaft includes a shaft main body (for example, camshafts 85 and 85A described later) and a drive-side piece (for example, an end portion of the drive shaft on the pump shaft side that is connected to the shaft main body. The pump shaft is connected to the pump shaft main body to constitute an end portion of the pump shaft on the drive shaft side, and is engaged with the drive side piece. A pump-side piece (for example, a pump-side connecting member 29 described later) that supplies lubricating oil flowing out from the drive-shaft lubricant passage to the drive-side piece and the pump-side piece, and the pump-shaft lubrication. The amount of lubricating oil that is diverted to that supplied to the oil passage and supplied to the pump shaft lubricating oil passage is the driving side piece It is preferably greater than the amount of lubricating oil supplied to the fine the pump-side piece.

According to the present invention, by engaging the pump side piece of the pump shaft with the drive side piece of the drive shaft, the drive shaft and the pump shaft are connected, and the lubricating oil flowing out from the drive shaft lubricating oil passage is The flow was divided into those supplied to the engaging portions of the drive side piece and the pump side piece and those supplied to the pump shaft lubricating oil passage. Furthermore, the amount of lubricating oil supplied to the radial bearing portion via the pump shaft lubricating oil passage is made larger than the amount of lubricating oil supplied to the drive side piece and the pump side piece.
By the way, the pump shaft is long as described above, and the sliding surface pressure between the pump shaft and the radial bearing portion is high. Therefore, the amount of lubricating oil required for the radial bearing portion is different between the drive side piece and the pump side piece. More than the amount of lubricant needed. Therefore, according to the present invention, lubricating oil can be supplied to the radial bearing portion, the drive side piece, and the pump side piece at an appropriate ratio.

  In this case, in the housing, one end of the housing opens to the engaging portion side surface of the drive side piece and the pump side piece, and the other end communicates with the radial bearing portion side (for example, described later). A reflux passage 39) is preferably drilled.

According to the present invention, the housing is provided with a return passage whose one end opens on the surface on the engagement portion side of the drive side piece and the pump side piece and whose other end communicates with the radial bearing portion side. As a result, the lubricating oil supplied to the radial bearing portion via the drive shaft lubricating oil passage and the pump shaft lubricating oil passage is returned to the driving side piece and the pump side piece side via the return passage, and the driving side piece and The engaging part of the pump side piece can be lubricated.
As described above, the amount of lubricating oil that is diverted from the driving shaft lubricating oil passage to the engaging portion of the driving side piece and the pump side piece is smaller than the amount of lubricating oil that is diverted to the pump shaft lubricating oil passage. Therefore, by returning the lubricating oil to the engaging portion of the driving side piece and the pump side piece, an appropriate amount of lubricating oil can be reliably supplied to the driving side piece and the pump side piece.

  In this case, it is preferable that the opening of the surface on the engaging portion side of the driving side piece and the pump side piece of the reflux passage is formed above the pump shaft main body.

  According to this invention, the opening of the surface on the engaging portion side of the driving side piece and the pump side piece of the reflux passage is formed above the pump shaft body. Thereby, the recirculated lubricating oil can be reliably supplied to the pump shaft body and the pump side piece and the drive side piece connected to the pump shaft body.

  In this case, the pump shaft lubricating oil passage is a first lubricating oil passage (for example, a first pump described later) extending in the axial direction from the distal end surface to the proximal end side with the drive shaft side as the distal end side of the pump shaft. Shaft passage 261) and a second lubricating oil passage (for example, a second pump shaft passage 262 to be described later) branched from the approximate center of the first lubricating oil passage and extending in the radial direction. Of the oil passage, the base end side from the branch portion of the second lubricating oil passage is preferably a bag-like lubricating oil reservoir chamber (for example, an oil reservoir chamber 263 described later).

According to this invention, the pump shaft lubricating oil passage has a first lubricating oil passage extending along the axial direction, and a second lubricating oil passage branched from the approximate center of the first lubricating oil passage and extending along the radial direction. And the base end side from the branch portion of the first lubricating oil passage is used as a lubricating oil reservoir chamber.
Therefore, the lubricating oil flowing out from the drive shaft lubricating oil passage is supplied to the radial bearing portion through the first lubricating oil passage and the second lubricating oil passage. In particular, the foreign matter contained in the lubricating oil may be captured in the lubricating oil reservoir chamber formed in the first lubricating oil passage. This can prevent the second lubricating oil passage from being clogged.

  In this case, in the housing, an axial end portion of the pump shaft of the driving force transmission member is in sliding contact, and a thrust restricting portion (for example, restricting movement of the driving force transmission member in the axial direction). It is preferable that a front end side thrust restricting portion 34 and a base end side thrust restricting portion 35, which will be described later, are formed, and fuel (for example, light oil fuel described later) is supplied to the thrust restricting portion.

According to the present invention, the axial end of the pump shaft of the driving force transmission member is slidably contacted in the housing to form a thrust restricting portion that restricts the movement of the driving force transmitting member. Fuel was supplied to the department.
Thus, by supplying fuel to the thrust restricting portion, it is not necessary to separately supply lubricating oil to the thrust restricting portion. For this reason, it can prevent that a fuel and lubricating oil mix and a lubricating oil deteriorates.

  In this case, it is preferable that a seal member (for example, an oil seal 38 to be described later) that partitions the radial bearing portion and the thrust restricting portion is provided in the housing.

  According to the present invention, the radial bearing portion and the thrust restricting portion are partitioned by the seal member, so that the lubricating oil supplied to the radial bearing portion and the fuel supplied to the thrust restricting portion are mixed, and the lubricating oil Can be reliably prevented from deteriorating.

  According to the high-pressure fuel pump of the present invention, the lubricity of the radial bearing portion can be improved by supplying the lubricating oil of the internal combustion engine to the radial bearing portion having a particularly high sliding surface pressure and a large load. That is, it is possible to reduce drive friction generated at the sliding contact portion between the pump shaft and the radial bearing portion and to prevent seizure of the pump shaft.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a configuration of a high-pressure fuel pump drive system according to the present embodiment.
FIG. 2 is a view showing a cross section taken along line II-II in FIG.

The high-pressure fuel pump drive system includes a high-pressure fuel pump 1 and a diesel engine (hereinafter simply referred to as “engine”) 8, and the low-pressure fuel pump 1 introduced into the high-pressure fuel pump 1 by the driving force from the engine 8. Light oil fuel (hereinafter simply referred to as “fuel”) is pressurized, and the pressurized fuel is discharged as high-pressure fuel.
Specifically, the high-pressure fuel pump 1 is provided in the fuel supply system of the engine 8. That is, the high-pressure fuel pump 1 is rotationally driven by a drive source of the engine 8, and when the fuel stored in the fuel tank is introduced by the low-pressure fuel pump, the fuel is pressurized and the engine 8 is connected via the common rail. High pressure fuel is supplied to an injector (not shown) provided in each cylinder.

  The high-pressure fuel pump 1 includes a long pump shaft 2, a housing 3 that rotatably accommodates the pump shaft 2, and a cylinder holder 4 provided with a cylinder 42 and a plunger 41.

  The high-pressure fuel pump 1 is a plunger pump that pressurizes fuel in a pressurizing chamber 43 formed inside the cylinder 42 by reciprocating the plunger 41 in the cylinder 42. In addition, the high-pressure fuel pump 1 of the present embodiment includes two cylinders 42 and plungers 41 that are opposed to each other with the pump shaft 2 interposed therebetween. The number of cylinders 42 and plungers 41, the positions with respect to the pump shaft 2, and the like are as follows. Not limited to.

[Configuration of pump shaft 2]
First, the configuration of the pump shaft 2 will be described.
The pump shaft 2 includes a long-sized pump shaft main body 21 centering on the line O and a cylindrical cam that is integrally formed on the base end side of the pump shaft main body 21 and constitutes the base end portion of the pump shaft 2. And a pump-side connecting member 29 as a pump-side piece that is connected to the distal end side of the pump shaft main body 21 and constitutes the distal end portion of the pump shaft 2.

  Such a pump shaft 2 is accommodated in the housing 3 except for the tip including the pump side connecting member 29. The tip of the pump shaft 2 is housed in the engine 8 and is connected to a drive shaft 81 as a drive source of the engine 8 via a pump-side connecting member 29.

As shown in FIG. 2, the central axis O ′ of the cam portion 22 is eccentric with respect to the central axis O of the pump shaft main body 21.
A polygon ring 23 having a substantially square cross section along a plane perpendicular to the central axis O of the pump shaft main body 21 is provided on the outer periphery of the cam portion 22. The center of the polygon ring 23 coincides with the central axis O ′ of the cam portion 22. The polygon ring 23 is connected to the cam portion 22 through an annular bush 24 and is rotatable with respect to the cam portion 22.

In the pump shaft 2 as described above, when the pump shaft main body 21 is driven to rotate about the central axis O by the drive source, the cam portion 22 rotates along with the rotation of the pump shaft main body 21, and the polygon ring 23 is Swing within the range of. Thereby, the driving force of the pump shaft main body 21 is transmitted to the plunger 41 in contact with one side surface of the polygon ring 23, and the plunger 41 is reciprocated.
That is, the driving force transmission member in the present embodiment includes the cam portion 22, the bush 24, and the polygon ring 23. In the following, it is assumed that the central axis O of the pump shaft body 21 and the rotation axis of the pump shaft 2 are equal.

Returning to FIG. 1, the configuration of the front end side of the pump shaft 2 will be described in detail.
As shown in FIG. 1, a pump shaft lubricating oil having one end opened to the front end surface of the pump shaft main body 21 and the other end communicating with the outer peripheral surface of the pump shaft main body 21 inside the pump shaft main body 21. A pump shaft passage 26 is formed as a passage.

  More specifically, the pump shaft passage 26 includes a first pump shaft passage 261 as a first lubricating oil passage that extends along the central axis O from the front end surface of the pump shaft main body 21 to the vicinity of the cam portion 22; A plurality of second pump shaft passages 262 as second lubricating oil passages that branch off from substantially the center of the first pump shaft passage 261 and extend in the radial direction to the outer peripheral surface of the pump shaft main body 21. Is done.

Further, an oil introduction pipe 28 as a cylindrical passage member is press-fitted into the distal end side of the first pump shaft passage 261. The oil introduction pipe 28 extends from the inside of the first pump shaft passage 261 to the drive shaft passage 846 described later of the drive shaft 81 facing the first pump shaft passage 261.
As will be described in detail later with reference to FIG. 5, engine oil in the engine 8 is supplied to the oil introduction pipe 28, the first pump shaft passage 261, and the second pump shaft passage 262.

[Configuration of housing 3]
Next, the configuration of the housing 3 will be described.
The housing 3 is configured by combining a main housing 31 that houses the distal end side of the pump shaft 2 and a housing cover 32 that covers the pump shaft 2 from the proximal end side, and rotatably supports the pump shaft 2.

The main housing 31 is formed in a flange shape, and supports the cam portion 22 of the pump shaft main body 21 and the front end side of the cam portion 22 so as to be rotatable.
Specifically, a cylindrical radial bearing portion that extends along the central axis O of the pump shaft main body 21 and has an outer peripheral surface in sliding contact with the front end side of the cam portion 22 of the pump shaft main body 21 is provided in the main housing 31. 33 and a front end side thrust restricting portion 34 that extends along the radial direction of the pump shaft main body 21 and is in sliding contact with the end portion on the front end side of the cam portion 22 and the polygon ring 23.

A seal housing chamber 37 for housing an oil seal 38 as an annular seal member is formed inside the main housing 31.
The seal housing chamber 37 is formed by engraving a concave groove between the radial bearing portion 33 and the front end side thrust restricting portion 34 in the main housing 31.

FIG. 3 is a cross-sectional view showing the configuration of the oil seal 38.
The oil seal 38 includes a resin seal body 381 and a metal annular member 384 that holds the seal body 381.

  The seal body 381 includes a seal outer peripheral portion 382 in which a substantially flat seal surface 382a is formed, and a seal inner peripheral portion 383 in which two seal lips 383a and 383b of protrusions are formed.

Such a seal body 381 is fitted in the seal housing chamber 37 with the seal outer peripheral portion 382 bonded to the annular member 384. Thereby, the inner peripheral surface of the seal accommodating chamber 37 and the seal surface 382a are in close contact with each other. The seal inner peripheral portion 383 is fastened to the pump shaft main body 21 by two garter springs 385a and 385b. As a result, the two seal lips 383 a and 383 b are in sliding contact with the outer peripheral surface of the pump shaft main body 21 closely.
By providing the oil seal 38 in the main housing 31 as described above, the radial bearing portion 33 and the tip side thrust restricting portion 34 are partitioned.

Returning to FIG. 1, in addition to this, inside the main housing 31, a reflux passage 39 having one end opened to the front end surface 313 of the main housing 31 and the other end communicating with the radial bearing portion 33 side is provided. .
More specifically, the recirculation passage 39 includes a first recirculation passage 391 that communicates the radial bearing portion 33 and the seal housing chamber 37, and a front end surface 313 of the main housing 31 from the seal housing chamber 37, that is, a pump side connecting member. 29 and a second return passage 392 extending to the surface on the drive shaft 81 side.
As will be described in detail later with reference to FIG. 5, the engine oil used for lubrication in the sliding contact portion between the radial bearing portion 33 and the pump shaft main body 21 is supplied with the first return passage 391 and the second return passage 392. Is then returned to the engine 8 via.

The housing cover 32 has a substantially disk shape, and is fixed to the main housing 31 in a state where the pump shaft main body 21 is covered from the base end side.
Specifically, the housing cover 32 has a proximal end side thrust regulating portion 35 slidably in contact with the proximal end portion of the pump shaft main body 21 and the proximal end portion of the cam portion 22 and the polygon ring 23. Is formed.

  When the housing cover 32 is fixed to the main housing 31, the cam portion 22, the polygon ring 23, and the gap between the base end side thrust restricting portion 35 of the housing cover 32 and the tip end side thrust restricting portion 34 of the main housing 31 are provided. A cylinder housing chamber 36 for housing the plunger 41 and the cylinder 42 is formed.

  In the housing 3 formed as described above, the pump shaft main body 21 is supported in the radial direction by the radial bearing portion 33. Further, both end portions of the cam portion 22 and the polygon ring 23 are supported in the rotational axis direction of the pump shaft 2 by the distal end side thrust restricting portion 34 and the proximal end side thrust restricting portion 35, and the movement along the rotational axis direction is restricted. Is done.

[Configuration of cylinder holder 4]
Next, the configuration of the cylinder holder 4 will be described.
The cylinder holder 4 includes a cylindrical cylinder 42 extending radially around the rotation axis of the pump shaft 2 and a rod-like plunger 41 accommodated inside the cylinder 42 so as to be capable of reciprocating. The cylinder holder 4 is fastened to the housing 3 by a plurality of fastening members 49 in a state where the plunger 41 and the cylinder 42 are inserted into a cylinder housing chamber 36 formed between the main housing 31 and the housing cover 32.

  In the cylinder holder 4, the pressurizing chamber 43 that pressurizes the fuel is defined by the inner wall surface of the cylinder 42 and the tip surface of the plunger 41. The base end portion 41 a of the plunger 41 is formed in a dish shape, and the base end portion 41 a of the plunger 41 is placed between the base end portion 41 a and the cylinder 42 on the outer peripheral surface of the polygon ring 23 of the pump shaft 2. A spring 44 as an urging mechanism that urges toward the surface is interposed.

The cylinder holder 4 is further formed with low-pressure passages 45 a, 45 b, 45 c that allow fuel to flow into the pressurizing chamber 43, and a high-pressure passage 46 that discharges fuel from the pressurizing chamber 43.
Among these, the low pressure fuel supplied from the fuel introduction part 11 flows into the low pressure passage 45a via a low pressure passage (not shown). The high-pressure passage 46 communicates with the discharge passage 12a of the fuel discharge portion 12 connected to the common rail.

  The low pressure passage 45c is provided with a low pressure check valve 47 for preventing the fuel from flowing back from the pressurizing chamber 43 side to the low pressure passage 45c side. The high pressure passage 46 is pressurized from the high pressure passage 46 side. A high-pressure check valve 48 that prevents the fuel from flowing back to the pressure chamber 43 side is provided.

  In the cylinder holder 4 configured as described above, when the pump shaft 2 is rotationally driven by a drive source, the polygon ring 23 swings within a predetermined movable range, whereby the plunger 41 reciprocates within the cylinder 42. Here, when fuel is supplied into the pressurizing chamber 43 from the low pressure passages 45a, 45b, 45c, the fuel in the pressurizing chamber 43 is pressurized to a high pressure by the plunger 41 and the high pressure side check valve 48 is opened. The high pressure fuel in the pressurizing chamber 43 is discharged from the fuel discharge section 12.

[Configuration of Engine 8]
Next, the configuration of the engine 8 will be described.
The engine 8 is connected to the front end of the pump shaft 2, a substantially rod-shaped drive shaft 81 that transmits a driving force to the pump shaft 2, a journal 82 that rotatably supports the drive shaft 81, and these drive shafts 81. And an engine main body 83 that accommodates the journal 82. In FIG. 1, only a portion related to driving of the high-pressure fuel pump 1 in the engine 8 is illustrated.

  The engine body 83 is formed with a through hole 831 that penetrates along the rotation axis O of the pump shaft 2. The high-pressure fuel pump 1 is fixed to the engine 8 with the front end side of the main housing 31 inserted into the through hole 831 and the front end portion of the pump shaft 2 and the front end portion of the drive shaft 81 connected to each other.

  The drive shaft 81 is a camshaft 85 as a shaft main body that opens and closes a valve (not shown) of the engine 8, and a drive side connection as a drive side piece that is coaxially connected to the camshaft 85 and constitutes the tip portion of the drive shaft 81. And a member 84.

FIG. 4 is an exploded perspective view showing the configuration of the distal end portion of the pump shaft 2 and the distal end portion of the drive shaft 81.
The pump side connecting member 29 includes a disk-like connecting member main body 291 and a pair of claw portions 292 and 293 extending in the radial direction from the end of the connecting member main body 291. A substantially rectangular through-hole 294 is formed in the center of the connecting member main body 291 in which a protrusion 211 formed on the distal end side of the pump shaft main body 21 is fitted.

The drive side connecting member 84 includes an output shaft 841 and a shaft coupling 842 provided integrally on the distal end side of the output shaft 841.
The proximal end side of the output shaft 841 is mechanically connected to a camshaft (not shown) and is rotationally driven by this camshaft.
The shaft coupling 842 has a substantially cylindrical shape, and an inside thereof is a housing portion 843 that houses the coupling member main body 291 of the pump side coupling member 29 in a substantially coaxial manner. In addition, a pair of groove portions 844 and 845 that engage with the claw portions 292 and 293 of the pump side connecting member 29 are formed on the distal end side of the shaft coupling 842.

In addition, a drive shaft passage 846 as a drive shaft lubricating oil passage whose one end opens on the surface on the housing portion 843 side is formed in the drive side connecting member 84 along the central axis.
Further, the pump side connecting member 29 and the drive side connecting member 84 are connected to the pump shaft main body 21 such that the respective central axes substantially coincide with the central axis O of the pump shaft main body 21. Thereby, the driving force of the camshaft 85 can be transmitted to the pump shaft 2.

[Composition of lubricant]
Next, the structure of the lubricant in the high pressure fuel pump 1 of the present embodiment will be described.
In the high-pressure fuel pump 1, two types of lubricants, that is, engine oil that circulates the engine 8 and fuel that is pressurized by the high-pressure fuel pump 1, are used as lubricants for lubricating the pump shaft 2.

More specifically, fuel is used as a lubricant in the regions indicated by broken lines 1a and 1b in FIG. 1, that is, in the front end side thrust restricting portion 34 and the base end side thrust restricting portion 35.
That is, when the fuel is pressurized by the plunger 41 in the pressurizing chamber 43, part of the pressurized fuel leaks into the cylinder housing chamber 36 from the gap between the plunger 41 and the cylinder 42. For this reason, the leaked fuel is supplied as a lubricant to the thrust regulating portions 34 and 35 formed as a part of the inner wall surface of the cylinder housing chamber 36.

  On the other hand, a part of engine oil circulating in the engine 8 is used as a lubricant in the region indicated by the broken line 1c in FIG. Below, the path | route of the engine oil in the high pressure fuel pump 1 is demonstrated with reference to FIG.5 and FIG.6.

FIG. 5 is a cross-sectional view showing the configuration of the front end side of the high-pressure fuel pump 1.
First, the drive shaft passage 846 formed in the drive side connecting member 84 has a distal end side that opens to the pump shaft 2 side, and a proximal end side that communicates with an engine oil passage (not shown) of the engine 8. For this reason, engine oil flowing through the engine oil passage is supplied to the drive shaft passage 846. The engine oil supplied to the drive shaft passage 846 flows out to the pump shaft 2 provided to face the drive side connecting member 84.

As shown in FIG. 5, the distal end side of the drive shaft passage 846 is formed in a tapered shape, and the inner diameter thereof is larger than the outer diameter of the oil introduction pipe 28 press-fitted into the distal end side of the pump shaft main body 21. Yes. Further, the tip of the oil introduction pipe 28 extends to the inside of the drive shaft passage 846.
Therefore, the engine oil flowing out from the drive shaft passage 846 flows through the oil introduction pipe 28 and flows into the pump shaft passage 26 in the pump shaft 2, and the engine oil that flows out of the oil introduction pipe 28 through the shaft coupling 842. The flow is divided into the flow into the storage portion 843.

  Here, the diversion ratio, that is, the ratio of the amount of engine oil supplied to the pump shaft passage 26 to the amount of engine oil supplied to the housing portion 843 is determined by the inner diameter of the oil introduction pipe 28, the oil introduction pipe 28, and the like. It is adjusted by the ratio to the clearance with the drive shaft passage 846. In the present embodiment, the amount of engine oil supplied to the pump shaft passage 26 is adjusted to be larger than the amount of engine oil supplied to the storage portion 843.

6 is a view showing a cross section taken along line VI-VI in FIG. 1, and is a view showing a cross section of the accommodating portion 843. In FIG.
The engine oil supplied to the storage portion 843 is supplied to the surfaces of the connecting member main body 91 and the claw portions 292 and 293 of the pump side connecting member 29, and is shown by the broken line 6a, that is, the pump side connecting member 29 and the shaft coupling 842. Lubricate the engaging part.

  On the other hand, returning to FIG. 5, the engine oil supplied to the pump shaft passage 26 circulates through the first pump shaft passage 261 and the second pump shaft passage 262, and from the second pump shaft passage 262 to the radial bearing portion 33 and the pump. It begins to ooze between the shaft body 21 and lubricates the sliding contact portion between the radial bearing portion 33 and the pump shaft body 21. Here, in particular, by dividing the radial bearing portion 33 and the tip side thrust restricting portion 34 by the oil seal 38 as described above, it is possible to prevent the engine oil from leaking to the tip side thrust restricting portion 34 side.

  Further, here, the base end side of the first pump shaft passage 261 from the branch portion of the second pump shaft passage 262 is a bag-like oil reservoir chamber 263. That is, foreign matter having a large particle size contained in the engine oil supplied from the front end side of the first pump shaft passage 261 can be stored in the oil reservoir chamber 263.

Further, the engine oil that has oozed out between the radial bearing portion 33 and the pump shaft main body 21 flows through the first return passage 391 and the second return passage 392, and from the front end surface 313 of the main housing 31 to the pump side connecting member 29. Then, it is returned to the engaging portion side of the drive side connecting member 84.
As shown in FIG. 6, the opening on the pump side connecting member 29 side of the second reflux passage 392 is formed above the pump shaft main body 21. Thereby, a part of the recirculated engine oil can be supplied to the surface of the pump-side connecting member 29 and the engaging portion between the pump-side connecting member 29 and the shaft coupling 842 can be lubricated.

According to this embodiment, there are the following effects.
(1) In the high-pressure fuel pump 1 in which the plunger 41 is reciprocated by rotating the pump shaft 2 to pressurize the fuel in the pressurizing chamber 43 inside the cylinder 42, the pump shaft main body 21 is arranged in the radial direction inside the housing 3. A radial bearing portion 33 to be supported by the engine 8 was formed, and engine oil flowing through the engine oil passage of the engine 8 was supplied to the radial bearing portion 33. As described above, the lubricity of the radial bearing portion 33 can be improved by supplying the engine oil to the radial bearing portion 33 having a particularly high sliding surface pressure and a large load. That is, it is possible to reduce the drive friction generated at the sliding contact portion between the pump shaft 2 and the radial bearing portion 33 and to prevent the pump shaft 2 from being seized.

(2) The engine oil flows through the drive shaft passage 846 formed in the drive shaft 81 and is supplied to the pump shaft passage 26 formed in the pump shaft 2 facing the drive shaft 81. Further, the engine oil supplied to the pump shaft passage 26 flows through the pump shaft passage 26 and is supplied to the radial bearing portion 33.
Thus, the passage for supplying engine oil to the radial bearing portion 33 is formed in the pump shaft 2 and the drive shaft 81 that rotationally drives the pump shaft 2. For this reason, it is not necessary to form an extra passage for introducing the engine oil flowing through the engine oil passage of the engine 8 into the housing 3 of the high-pressure fuel pump 1, so that the high-pressure fuel pump 1 can be reduced in size.

  (3) A cylindrical oil introduction pipe 28 extending from one passage to the other passage side is provided in at least one of the drive shaft passage 846 and the pump shaft passage 26. As a result, a stable amount of engine oil can be supplied from the drive shaft passage 846 to the pump shaft passage 26.

(4) By engaging the pump-side connecting member 29 of the pump shaft 2 with the driving-side connecting member 84 of the drive shaft 81, the drive shaft 81 and the pump shaft 2 are connected and flow out of the drive shaft passage 846. The engine oil was divided into the oil supplied to the engaging portions of the drive side connecting member 84 and the pump side connecting member 29 and the oil supplied to the pump shaft passage 26. Furthermore, the amount of engine oil supplied to the radial bearing portion 33 via the pump shaft passage 26 is made larger than the amount of engine oil supplied to the engaging portions of the drive side connecting member 84 and the pump side connecting member 29.
By the way, since the pump shaft 2 is long as described above and the sliding surface pressure between the pump shaft 2 and the radial bearing portion 33 is high, the amount of engine oil required for the radial bearing portion 33 is determined by the drive side connecting member. 84 and the amount of engine oil required for the engaging portion of the pump side connecting member 29 is larger. Therefore, according to the present invention, lubricating oil can be supplied to the radial bearing portion 33 and the engaging portions of the drive side connecting member 84 and the pump side connecting member 29 at an appropriate ratio.

(5) In the housing 3, a reflux passage 39 having one end opened in the engaging portion side surface of the drive side connecting member 84 and the pump side connecting member 29 and the other end communicating with the radial bearing portion 33 side is provided. did. As a result, the engine oil supplied to the radial bearing portion 33 through the drive shaft passage 846 and the pump shaft passage 26 is returned to the drive side connecting member 84 and the pump side connecting member 29 through the return passage 39. The engaging portions of the drive side connecting member 84 and the pump side connecting member 29 can be lubricated.
As described above, the amount of engine oil that is diverted from the drive shaft passage 846 to the engaging portion of the drive side connecting member 84 and the pump side connecting member 29 is smaller than the amount of engine oil that is diverted to the pump shaft passage 26. Therefore, an appropriate amount of engine oil can be reliably supplied to the drive side connection member 84 and the pump side connection member 29 by returning the engine oil to the engagement portion of the drive side connection member 84 and the pump side connection member 29. .

  (6) The openings on the engaging portion side surfaces of the driving side connecting member 84 and the pump side connecting member 29 of the reflux passage 39 are formed above the pump shaft main body 21. Thereby, the recirculated engine oil can be reliably supplied to the pump shaft main body 21, the pump side connecting member 29 and the drive side connecting member 84 connected to the pump shaft main body 21.

(7) The first pump shaft passage 261 extending along the rotational axis direction of the pump shaft passage 26, and the second pump shaft passage 262 extending from the approximate center of the first pump shaft passage 261 and extending along the radial direction. In addition, an oil reservoir chamber 263 is formed on the base end side from the branch portion in the first pump shaft passage 261.
Therefore, the engine oil flowing out from the drive shaft passage 846 flows through the first pump shaft passage 261 and the second pump shaft passage 262 and is supplied to the radial bearing portion 33. In particular, the foreign matter contained in the engine oil may be captured in the oil reservoir chamber 263 formed in the first pump shaft passage 261 in some cases. Thereby, it is possible to prevent the second pump shaft passage 262 from being clogged.

(8) The distal end side thrust restricting portion 34 and the proximal end side thrust that restrict the movement of the driving force transmitting member in the housing 3 in which the end of the driving force transmitting member on the rotating shaft direction side of the pump shaft 2 is in sliding contact. The regulating part 35 was formed, and fuel was supplied to the thrust regulating parts 34 and 35.
Thus, by supplying fuel to the thrust regulating portions 34 and 35, it is not necessary to separately supply engine oil to these thrust regulating portions 34 and 35. For this reason, it is possible to prevent the fuel and engine oil from being mixed and the engine oil from deteriorating.

  (9) By dividing the radial bearing portion 33 and the thrust restricting portions 34 and 35 by the oil seal 38, the engine oil supplied to the radial bearing portion 33 and the fuel supplied to the thrust restricting portions 34 and 35 are Mixing can reliably prevent the engine oil from deteriorating.

Second Embodiment
A high-pressure fuel pump drive system according to a second embodiment of the present invention will be described with reference to FIG.
In the following description of the second embodiment, the same constituent elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

FIG. 7 is a cross-sectional view showing the configuration of the high-pressure fuel pump drive system according to this embodiment.
The high pressure fuel pump drive system of the present embodiment differs from the high pressure fuel pump drive system of the first embodiment in the configuration of a drive shaft 81A of an engine 8A that drives the high pressure fuel pump 1. The drive shaft 81A of the present embodiment is different from the drive shaft 81 of the first embodiment in that the camshaft 85A and the drive-side connecting member 84A are provided separately and connected via a shaft gear 88.

Specifically, the drive shaft 81A includes a journal 89 that rotatably supports the output shaft 841A of the drive side connecting member 84A, and a shaft gear 88 that is connected to the base end side of the output shaft 841A.
The shaft gear 88 meshes with a gear (not shown) provided on the camshaft 85A, thereby transmitting the rotation of the camshaft 85A to the drive side connecting member 84A.

The drive shaft passage 846A of the drive side connecting member 84A has a first drive shaft passage 848 extending along the central axis, and a first extension extending along the radial direction from the first drive shaft passage 848 to the outer peripheral surface of the output shaft 841A. 2 drive shaft passage 849.
The second drive shaft passage 849 communicates with an engine oil passage (not shown) of the engine 8A. For this reason, the second drive shaft passage 849 is supplied with engine oil that flows through the engine oil passage, passes through the first drive shaft passage 848, and is provided opposite to the drive side connecting member 84A. To the side.

  According to the present embodiment, there are the same effects as the high-pressure fuel pump drive system of the first embodiment.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

  In the above embodiment, the drive shaft 81 and the pump shaft 2 are connected by the drive side connecting member 84 and the pump side connecting member 29 so that the center axis of the drive shaft 81 and the center axis of the pump shaft 2 are coaxial. However, it is not limited to this. For example, the drive shaft and the pump shaft may be connected by shifting both axes.

In the above embodiment, the oil introduction pipe 28 is press-fitted into the pump shaft passage 26, but the oil introduction pipe 28 is not necessarily provided. The oil introduction pipe 28 is provided mainly for adjusting the amount of engine oil introduced into the pump shaft passage 26. Therefore, when the amount of engine oil introduced into the pump shaft passage is appropriate, it is not necessary to provide this oil introduction pipe.
Moreover, in the said embodiment, although this oil introduction pipe | tube 28 was press-fit in the pump shaft channel | path 26, it is not restricted to this. For example, you may press-fit into a drive shaft channel.

It is sectional drawing which shows the structure of the high pressure fuel pump drive system which concerns on 1st Embodiment of this invention. It is a figure which shows the cross section along line II-II of FIG. It is sectional drawing which shows the structure of the oil seal which concerns on the said embodiment. It is a disassembled perspective view which shows the structure of the front-end | tip part of the pump shaft which concerns on the said embodiment, and the front-end | tip part of a drive shaft. It is a figure which shows the path | route of the engine oil which concerns on the said embodiment. It is a figure which shows the cross section along line VI-VI of FIG. It is sectional drawing which shows the structure of the high pressure fuel pump drive system which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... High pressure fuel pump 2 ... Pump shaft 21 ... Pump shaft main body 22 ... Cam part (driving force transmission member)
23 ... Polygon ring (driving force transmission member)
24 ... Bush (driving force transmission member)
26 ... pump shaft passage (pump shaft lubricating oil passage)
261: first pump shaft passage (first lubricating oil passage)
262 ... second pump shaft passage (second lubricating oil passage)
263 ... Oil reservoir chamber (lubricant reservoir chamber)
28 ... Oil introduction pipe (passage member)
29 ... Pump side connecting member (Pump side piece)
DESCRIPTION OF SYMBOLS 3 ... Housing 33 ... Radial bearing part 34 ... Front end side thrust control part (Thrust control part)
35 ... Base end side thrust restricting portion (thrust restricting portion)
38 ... Oil seal (seal member)
39 ... Reflux passage 4 ... Cylinder holder 41 ... Plunger 42 ... Cylinder 43 ... Pressurizing chamber 44 ... Spring (biasing mechanism)
8,8A ... Engine (internal combustion engine)
81, 81A ... Drive shaft 84, 84A ... Drive side connecting member (drive side piece)
85,85A ... Camshaft (shaft body)
846, 846A ... Drive shaft passage (drive shaft lubricating oil passage)

Claims (9)

A high-pressure fuel pump that supplies fuel at a high pressure to a fuel injection valve of an internal combustion engine,
A housing;
A pump shaft that is rotationally driven by a drive source of the internal combustion engine;
Cylinders arranged radially around the rotation axis of the pump shaft;
A plunger accommodated in the cylinder so as to be capable of reciprocating;
A pressurizing chamber defined by the cylinder and the plunger;
A biasing mechanism that biases the end of the plunger on the pump shaft side toward the pump shaft;
The pump shaft is driven by rotation of the pump source by a long pump shaft main body, and the pump shaft main body is driven to rotate, and the driving force of the pump shaft main body is transmitted to the plunger. A driving force transmission member that reciprocates,
In the housing, a radial bearing portion is formed in which the outer peripheral surface of the pump shaft main body slides and supports the pump shaft main body in the radial direction,
The high pressure fuel pump according to claim 1, wherein the radial bearing portion is supplied with lubricating oil flowing through a lubricating oil passage of the internal combustion engine. Using a drive shaft as a drive source of the internal combustion engine,
One end surface of the pump shaft is provided to face one end surface of the drive shaft,
In the drive shaft, a drive shaft lubricating oil passage that has one end opened to the end surface on the pump shaft side and the other end communicated with the lubricating oil passage of the internal combustion engine is provided,
In the pump shaft, a pump shaft lubricating oil passage having one end side opened to the end surface on the drive shaft side and the other end side communicating with the radial bearing portion side is formed,
The high pressure fuel pump according to claim 1, wherein lubricating oil is supplied from the drive shaft lubricating oil passage to the pump shaft lubricating oil passage.   3. A cylindrical passage member extending from one passage to the other passage is provided in at least one of the drive shaft lubricant passage and the pump shaft lubricant passage. The high-pressure fuel pump described in 1. The drive shaft includes a shaft main body, and a drive side piece connected to the shaft main body and constituting an end of the drive shaft on the pump shaft side,
The pump shaft includes a pump side piece that is connected to the pump shaft main body and constitutes an end of the pump shaft on the drive shaft side, and engages with the drive side piece,
Lubricating oil flowing out from the drive shaft lubricating oil passage is divided into one that supplies the driving side piece and the pump side piece, and one that supplies the pump shaft lubricating oil passage,
3. The high-pressure fuel pump according to claim 2, wherein an amount of lubricating oil supplied to the pump shaft lubricating oil passage is larger than an amount of lubricating oil supplied to the driving side piece and the pump side piece.   One end of the housing is opened in the engaging part side surface of the drive side piece and the pump side piece, and the other end is provided with a reflux passage communicating with the radial bearing part side. The high-pressure fuel pump according to claim 4.   6. The high-pressure fuel pump according to claim 5, wherein the opening of the surface on the engagement portion side of the driving side piece and the pump side piece of the reflux passage is formed above the pump shaft main body. The drive shaft side as the tip side of the pump shaft,
The pump shaft lubricating oil passage includes a first lubricating oil passage extending in the axial direction from the distal end surface to the proximal end side, and a second lubrication extending from the approximate center of the first lubricating oil passage and extending along the radial direction. Including an oil passage,
3. The high-pressure fuel pump according to claim 2, wherein a proximal end side of the first lubricating oil passage from a branch portion of the second lubricating oil passage is a bag-like lubricating oil reservoir chamber. In the housing, a thrust restricting portion for restricting movement of the driving force transmitting member in the axial direction is formed by slidingly contacting an end portion of the pump shaft in the axial direction of the driving force transmitting member,
The high-pressure fuel pump according to claim 1, wherein fuel is supplied to the thrust restricting portion.   The high-pressure fuel pump according to claim 8, wherein a seal member that partitions the radial bearing portion and the thrust restricting portion is provided in the housing.

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