JP2016148293A - High pressure pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure pump for allowing simple replacement of a fuel seal.SOLUTION: The high pressure pump includes: an annular fuel seal 30 provided at the other axial end of a cylinder body 7 for blocking a gap between the cylinder body 7 and a plunger 9 to prevent the flow of fuel to the outside of the cylinder body 7; and a holder 32 supporting the fuel seal 30 and connected to the other axial end of the cylinder body 7. The holder 32 includes: a bottom part 40 penetrating through the plunger 9; a plurality of connection parts 43 connecting the bottom part 40 and the cylinder body 7; and claw parts 45 provided on the respective connection parts 43. The cylinder body 7 includes grooves 46 into which the respective claw parts 45 are fitted. Thus, the holder 32 is detachable from the cylinder body 7 to ensure easy access to the fuel seal 30 supported by the holder 32.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a high-pressure pump that pressurizes fuel sucked into a pressurizing chamber by reciprocating movement of a plunger.

Conventionally, it has a plunger that can reciprocate in the axial direction and a cylinder hole that slidably supports and accommodates this plunger in the axial direction, and one axial end of the cylinder hole is defined by one axial end of the plunger. Therefore, a high-pressure pump having a cylinder body in which a pressurizing chamber capable of pressurizing fuel is formed is well known.
In such a high-pressure pump, the volume of the pressurizing chamber is varied by reciprocating the plunger to pressurize the fuel sucked into the pressurizing chamber.

  Further, in such a high-pressure pump, an annular fuel seal provided at the other end in the axial direction of the cylinder body to prevent the fuel from flowing out of the cylinder body by closing the gap between the cylinder body and the plunger, and the fuel A structure including a holder that supports the seal and is connected to the other axial end of the cylinder body is known (see, for example, Patent Documents 1 to 4).

By the way, in the high-pressure pump as described above, the fuel seal is made of a resin material such as a fluorocarbon resin having excellent sliding characteristics. However, the fuel seal is deteriorated over time as compared with the surrounding metal members. It is getting faster.
However, in the high-pressure pumps of Patent Documents 1 to 4, the holder is formed integrally with the cylinder body, or the holder is connected to the cylinder body by being press-fitted into the cylinder body. It was extremely difficult to separate the cylinder body from the cylinder body.
For this reason, it is very difficult to access the fuel seal supported by the holder, and there is a problem that it is difficult to replace only the fuel seal that deteriorates quickly.

JP 2003-206825 A JP 2007-187114 A JP 2010-127153 A JP 2014-77361 A

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a high-pressure pump in which a fuel seal can be easily replaced.

According to the first invention of the present application, the high-pressure pump has a plunger that can reciprocate in the axial direction and a cylinder hole that supports and accommodates the plunger so as to be slidable in the axial direction. A cylinder body in which a pressurizing chamber capable of pressurizing fuel is formed by partitioning with one end in the axial direction of the plunger.
An annular fuel seal that is provided at the other axial end of the cylinder body and prevents the fuel from flowing out of the cylinder body by closing the gap between the cylinder body and the plunger, and supports the fuel seal, and the cylinder A holder connected to the other axial end of the body.
The high-pressure pump pressurizes the fuel sucked into the pressurizing chamber by reciprocating the plunger to change the volume of the pressurizing chamber.

The holder includes a bottom portion through which the plunger passes, a plurality of connecting portions that connect the bottom portion and the cylinder body, and a claw portion provided in the connecting portion.
The cylinder body includes a groove into which the claw portion is fitted.
Here, the holder is connected to the cylinder body by fitting the claw portion into the groove, and can be removed from the cylinder body by removing the claw portion from the groove.

As a result, the holder is detachable from the cylinder body, so that the holder can be easily detached from the cylinder body.
For this reason, the fuel seat supported by the holder can be easily accessed, and the fuel seal can be easily replaced.
In addition, since the connection part is provided with two or more by the holder and each connection part can deform | transform independently, the attachment or detachment of a holder is easy.

According to the second invention of the present application, the other axial end of the plunger is exposed in the space where the lubricating oil exists.
The holder has an annular oil seal that prevents the lubricating oil from flowing into the cylinder body by closing the gap between the holder and the plunger.
Thereby, since the holder can be easily removed from the cylinder body, the holder can be removed from the cylinder body, and the oil seal of the holder can be easily replaced.

It is a whole high-pressure pump block diagram (example). It is principal part explanatory drawing of a high pressure pump (Example). It is explanatory drawing of a holder (Example). It is principal part explanatory drawing of a high pressure pump (modification). It is principal part explanatory drawing of a high pressure pump (modification). It is principal part explanatory drawing of a high pressure pump (modification).

  Hereinafter, modes for carrying out the invention will be described based on examples.

An overall configuration of a high-pressure pump 1 according to an embodiment of the present invention is shown in FIG. FIG. 1 is a partial cross-sectional view of the high-pressure pump 1.
The high pressure pump 1 is used by being mounted on a vehicle, pressurizes fuel supplied from a fuel tank (not shown) by a low pressure pump (not shown), and is connected to an injector (not shown). It discharges to the common rail (not shown) which is a rail. A pipe from the low pressure pump is connected to the upstream side of the fuel inlet of the high pressure pump 1.

The high-pressure pump 1 is driven by an internal combustion engine (not shown), and pumps fuel to the injector through a high-pressure pipe and a common rail that is a fuel rail as a high-pressure fuel accumulator.
Note that the pressure of the common rail fuel is controlled based on the rotational speed and load of the internal combustion engine, the temperature of the fuel, intake air, cooling water, and the input pressure from the low-pressure pump.

The high-pressure pump 1 includes a camshaft 3 that is driven by an internal combustion engine that is rotatably attached to the lower side of the pump body 2.
Here, the camshaft 3 is configured to include two cam portions (not shown), but it goes without saying that the number of cam portions is not limited to this number.
In addition, the space where a cam part etc. is arranged becomes a space where lubricating oil for sliding between members exists abundantly.

Each of the cam portions abuts on the tappet 5 and moves the tappet 5 in the vertical direction in the figure as the camshaft 3 rotates.
A cylinder body 7 is fixed to the pump body 2 while maintaining a predetermined distance from the tappet 5 in an opening on the upper side of the pump body 2 in the figure.
The tappet 5 reciprocally slides a cylindrical plunger 9 urged downward in the figure by a compression coil spring 8 in the vertical direction in the figure along the inner wall of the cylinder body 7 in which the cylinder hole 7a is formed.
In the following embodiments and the like, the axial direction of the plunger 9 and the axial direction of the cylinder body 7 are the same and coaxial, and the plunger 9, the cylinder body 7, and its peripheral members have one axial end. The side may be referred to as one end side, and the other axial end side may be referred to as the other end side.

An annular first fuel chamber 10 filled with fuel supplied by a low pressure pump is formed between the pump body 2 and the cylinder body 7.
A solenoid valve 15 for control is screwed into the opening on one end side of the cylinder body 7. An annular second fuel chamber 16 is formed between the electromagnetic valve 15 and the cylinder body 7.
A space defined by the electromagnetic valve 15, the cylinder body 7, and the plunger 9 is a pressurizing chamber 18.
That is, the pressurizing chamber 18 is formed by defining one axial end of the cylinder hole 7 a by one axial end of the plunger 9.

The fuel from the first fuel chamber 10 is filled into the second fuel chamber 16 through the introduction passage 20 formed in the side wall of the cylinder body 7.
The fuel in the second fuel chamber 16 is supplied to the pressurizing chamber 18 through a communication path (not shown) formed in the electromagnetic valve 15.

The housing 7 is provided with a discharge valve (not shown). The discharge valve has a so-called check valve structure and communicates with the pressurizing chamber 18 through a discharge passage (not shown), and sends high-pressure fuel from the pressurizing chamber 18 to the common rail.
The discharge valve closes as the pressure in the pressurizing chamber 18 decreases, and the common rail pressure is maintained at a predetermined pressure.

Here, the operation of the high-pressure pump 1 will be briefly described.
First, as the camshaft 3 is driven to rotate, the cam portion drives the tappet 5 toward one end, displaces the plunger 9 toward one end against the urging force of the compression spring 8, and increases the volume of the pressurizing chamber 18. to shrink.
For this reason, the fuel in the pressurizing chamber 18 is fed into the second fuel chamber 16 through the communication passage of the electromagnetic valve 15.

  When the solenoid valve 15 is energized in accordance with the rotational speed of the internal combustion engine or the low-pressure pump and the accelerator opening degree in the process of driving the tappet 5 to one end side, the solenoid valve 15 is closed, and the second fuel chamber 16 Communication with the pressurizing chamber 18 is blocked.

  Further, when the tappet 5 is driven to one end side with the rotation of the camshaft 3, the volume of the pressurizing chamber 18 is further reduced by the displacement of the plunger 9 to the one end side. Thereby, the pressure in the pressurizing chamber 18 rises. In this process, when the pressure in the pressurizing chamber 18 exceeds the sum of the common rail pressure and the set valve opening pressure of the discharge valve, the discharge valve is opened and fuel is pumped to the common rail.

  When the tappet 5 reaches a so-called top dead center, the pressurization of the pressurizing chamber 18 by the plunger 9 is stopped, and the fuel pressure in the pressurizing chamber 18 starts to decrease. When the tappet 5 starts to be driven to the other end side, the pressure in the pressurizing chamber 18 further decreases, the discharge valve closes, and the common rail is maintained at a predetermined pressure.

Further, when the tappet 5 is driven to the other end side with the rotation of the camshaft 3, the pressure in the pressurizing chamber 18 continues to decrease, and the solenoid valve 15 is opened by stopping the energization of the solenoid valve 15. The pressure chamber 18 is again filled with fuel from the second fuel chamber 16.
Further, when the tappet 5 reaches a so-called bottom dead center with the rotation of the camshaft 3, the reciprocation of the plunger 9 is completed and one cycle is completed.

  That is, the high-pressure pump 1 has a plunger 9 that can reciprocate in the axial direction, and a cylinder hole 7a that supports and accommodates the plunger 9 slidably in the axial direction. One end of the cylinder hole 7a in the axial direction is a plunger. 9 is provided with a cylinder body 7 in which a pressurizing chamber 18 capable of pressurizing fuel is formed, and the volume of the pressurizing chamber 18 is varied by reciprocating the plunger 9. The fuel sucked into the pressurizing chamber 18 is pressurized.

The high pressure pump 1 is provided with a seal portion 23 at the other end of the cylinder body 7.
The seal portion 23 closes the gap between the cylinder body 7 and the plunger 9 and prevents the fuel from flowing out of the cylinder body 7. The seal portion 23 supports the fuel seal 30 and the cylinder body 7. And a holder 32 connected to the other end.

Here, the seal portion 23 will be described in detail with reference to FIGS.
The other end of the cylinder body 7 has a bottomed cylindrical shape with the opening on the other end side, and the plunger 9 penetrates the bottom.
An annular fuel seal 30 is provided at the other end of the cylinder body 7 to prevent the fuel from flowing out of the cylinder body 7 by closing the gap between the cylinder body 7 and the plunger 9.
The fuel seal 30 is made of a resin such as a fluorocarbon resin having excellent sliding characteristics and fuel resistance characteristics.

An O-ring 33 is disposed on the outer peripheral side of the fuel seal 30 so as to surround the fuel seal 30. The O-ring 33 is a backup ring that gives an elastic force for ensuring the contact performance of the fuel seal 30 to the outer peripheral surface of the plunger 9, and is made of rubber.
The holder 32 supports the fuel seal 30 and the O-ring 33 via the spacer 35 and is connected to the other end of the cylinder body 7.
The spacer 35 is a cylindrical body provided with a groove into which a rubber O-ring 37 is fitted on the outer peripheral side, so that the spacer 35 can be easily fitted into the cylinder body 7 or removed from the cylinder body 7 easily. It has become.

As shown in FIGS. 2 and 3, the holder 32 includes a bottom portion 40 through which the plunger 9 passes, a plurality of connecting portions 43 that connect the bottom portion 40 and the cylinder body 7, and a claw portion 45 provided on the connecting portion 43. It has.
Further, the cylinder body 7 includes a groove 46 into which the claw portion 45 is fitted on the outer periphery of the other end portion of the cylinder body 7.
The groove 46 may be provided over the entire outer periphery of the cylinder body 7 or may be provided only in a portion where the claw portion 45 is fitted.
The holder 32 is connected to the cylinder body 7 by fitting the claw portion 45 into the groove 46, and can be detached from the cylinder body 7 by removing the claw portion 45 from the groove 46.

Further, the other end of the plunger 9 protrudes out of the cylinder body 7 and is exposed to a space where lubricating oil is disposed such as a cam portion.
The holder 32 has an annular oil seal 50 that prevents the lubricating oil from flowing into the cylinder body 7 by closing the gap between the holder 32 and the plunger 9.
Here, the oil seal 50 is made of an annular rubber, and is fitted into the through hole of the bottom portion 40 so as to close the gap between the through hole of the bottom portion 40 through which the plunger 9 passes and the outer peripheral surface of the plunger 9.
A garter spring 52 is disposed on the outer periphery of the oil seal 50. The garter spring 52 is a backup ring that provides an elastic force for ensuring the contact performance of the oil seal 50 to the outer peripheral surface of the plunger 9.

[Effects of Examples]
In the high-pressure pump 1 of the embodiment, the holder 32 includes a bottom portion 40 through which the plunger 9 penetrates, a plurality of connecting portions 43 that connect the bottom portion 40 and the cylinder body 7, and a claw portion 45 provided on the connecting portion 43. It has.
Further, the cylinder body 7 includes a groove 46 into which the claw portion 45 is fitted.
Here, the holder 32 is connected to the cylinder body 7 by fitting the claw portion 45 into the groove 46, and can be detached from the cylinder body 7 by removing the claw portion 45 from the groove 46.

Thereby, since the holder 32 becomes detachable from the cylinder body 7, the holder 32 can be easily detached from the cylinder body 7.
For this reason, the fuel seal 30 supported by the holder 32 can be easily accessed, and the fuel seal 30 can be easily replaced.
In addition, since the connection part 43 is provided with two or more by the holder 32 and each connection part 43 can be independently deform | transformed in a diameter-expanding direction, the attachment or detachment of the holder 32 is easy.

In the high pressure pump 1 of the embodiment, the holder 32 supports the fuel seal 30 via the spacer 35.
Thereby, the freedom degree of the shape of the seal | sticker part 23 can be raised by changing the shape of a spacer 35, a magnitude | size, etc. FIG.

In the high-pressure pump 1 of the embodiment, the other end portion of the plunger 9 is exposed in the space where the lubricating oil exists, and the holder 32 closes the gap between the holder 32 and the plunger 9, thereby An annular oil seal 50 is provided to prevent inflow of the oil.
Thereby, since the holder 32 can be easily removed from the cylinder body 7, the oil seal 50 of the holder 32 can be easily replaced by removing the holder 32 from the cylinder body 7.

[Modification]
Various modifications can be considered for the present invention without departing from the gist thereof.
In the drawings showing the following modified examples, the same functional components as those in the embodiments are denoted by the same reference numerals.
In the embodiment, the spacer 35 and the holder 32 have the oil seal 50, but the spacer 35 and the oil seal 50 may be omitted as shown in FIG.
Thereby, the axial length of the seal portion 23 can be reduced.

In the embodiment, the fuel seal 30, the O-ring 33, and the spacer 35 are handled separately, but as shown in FIG. 5, the fuel seal 30 and the O-ring 33 are separated from the two spacers 35, and These can be handled as an integral unit 56 by being sandwiched by the spacer 55 and held by the holder 32. Thereby, the exchange operation including the peripheral part of the fuel seal 30 can be easily performed.
The unit 56 and the cylinder body 7 are connected via an O-ring 57 embedded in a groove provided at the other end of the cylinder body 7. The unit 56 is easily connected to the cylinder body 7 by fitting the claw portion 45 into the groove 46 of the cylinder body 7, and can be easily detached from the cylinder body 7 by removing the claw portion 45 from the groove 46.
The unit 56 also includes the oil seal 50 and the garter spring 52, but the unit 56 may not include the oil seal 50 and the garter spring 52.

In the embodiment, the holder 32 has the oil seal 50. However, the oil seal 50 may be supported by the holder 32 via the spacer 35 as shown in FIG.
Here, the oil seal 50 is a rubber ring having a substantially U-shaped cross section with the open end at the other end, and the gap between the spacer 35 and the plunger 9 is closed to enter the lubricating oil into the cylinder body 7. Prevent the inflow.
The fuel seal 30 is a rubber ring having a substantially U-shaped cross section with an open end at one end, and is supported by the holder 32 via a spacer 35.
Thereby, since the oil seal 50 can also be supported by the spacer 35, the degree of freedom of the shape of the seal portion 23 can be increased by changing the shape, size, etc. of the spacer 35.

1 High pressure pump 7 Cylinder body 7a Cylinder hole 9 Plunger
18 Pressurizing chamber 30 Fuel seal 32 Holder 40 Bottom portion 43 Connecting portion 45 Claw portion 46 Groove

Claims (4)

A plunger (9) capable of reciprocating in the axial direction;
The plunger (9) has a cylinder hole (7a) that slidably supports and accommodates in the axial direction, and one axial end of the cylinder hole (7a) is defined by one axial end of the plunger (9). A cylinder body (7) in which a pressurizing chamber (18) capable of pressurizing fuel is formed;
An annular ring provided at the other axial end of the cylinder body (7) to prevent the fuel from flowing out of the cylinder body (7) by closing the gap between the cylinder body (7) and the plunger (9). A fuel seal (30) of
A holder (32) for supporting the fuel seal (30) and connected to the other axial end of the cylinder body (7);
In the high-pressure pump (1) that pressurizes the fuel sucked into the pressurizing chamber (18) by reciprocating the plunger (9) to change the volume of the pressurizing chamber (18),
The holder (32) includes a bottom portion (40) through which the plunger (9) passes, a plurality of connecting portions (43) connecting the bottom portion (40) and the cylinder body (7), and the connecting portions (43 ) Provided with a claw part (45) provided on,
The cylinder body (7) includes a groove (46) into which the claw portion (45) is fitted,
The holder (32) is connected to the cylinder body (7) by fitting the claw portion (45) into the groove (46), and the claw portion (45) is removed from the groove (46). A high-pressure pump (1) characterized in that it can be removed from the cylinder body (7). The high-pressure pump (1) according to claim 1,
The high-pressure pump (1), wherein the holder (32) supports the fuel seal (30) through a spacer (35). The high-pressure pump (1) according to claim 1 or claim 2,
The other axial end of the plunger (9) is exposed in the space where the lubricating oil exists,
The holder (32) has an annular oil seal (50) that blocks the gap between the holder (32) and the plunger (9), thereby preventing lubricating oil from flowing into the cylinder body (7). A high-pressure pump (1) characterized by that. The high-pressure pump (1) according to claim 2,
The other axial end of the plunger (9) is exposed in the space where the lubricating oil exists,
The holder (32) includes an annular oil seal (50) that prevents the inflow of lubricating oil into the cylinder body (7) by closing a gap between the spacer (35) and the plunger (9). A high-pressure pump (1) characterized by being supported via a spacer (35).

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