JP6805027B2 - Fuel supply pump - Google Patents

Description

The present invention relates to a fuel supply pump provided in an engine fuel supply system.

As a system for supplying fuel to an engine such as a diesel engine, the fuel in the common rail is maintained at a high pressure by pressurizing and supplying fuel to the common rail to which the injector is connected by a fuel supply pump, and fuel injection control by the injector is performed. Accumulation fuel supply systems that have made it possible are known. The fuel supply pump provided in the accumulator fuel supply system is attached to the engine via a flange connected to the housing. The fuel supply pump is driven by transmitting the driving force output from the crankshaft of the engine to the camshaft inserted into the flange.

In such a fuel supply pump, for example, as shown in Patent Document 1, in order to seal between the inner peripheral surface of the flange and the outer peripheral surface of the camshaft, the two are spaced apart from each other in the axial direction of the camshaft. Two sealing members are provided. Of the two seal members, the seal member arranged on the cam chamber side of the fuel supply pump suppresses the leakage of fuel in the fuel supply pump. Further, the seal member arranged on the engine side opposite to the cam chamber side prevents the lubricating oil of the engine from entering the fuel supply pump side. The space formed between these two sealing members communicates with the outside of the fuel supply pump through a communication hole formed in the flange. Therefore, when the camshaft rotates, air is sucked from the outside of the fuel supply pump into the space between the two seal members by the pumping action. As a result, the sealing property against the leakage of fuel from the inside of the fuel supply pump and the leakage of lubricating oil from the inside of the engine is further enhanced.

Japanese Unexamined Patent Publication No. 2016-217164

However, the fuel supply pump stops when adverse conditions such as foreign matter invading the part sealed by the sealing member or deterioration of the sealing part due to the foreign matter overlap, and the sealing property of the sealing part is significantly deteriorated. If the pumping action does not occur, the fuel may seep out. At this time, if the communication hole formed in the flange is provided downward in the vertical direction, the fuel in the space leaks to the outside of the fuel supply pump through the communication hole. On the other hand, if the communication hole is provided at a high position, rainwater, foreign matter, or the like may enter the space from the outside of the fuel supply pump.

Therefore, it is desirable that the communication hole is provided at a position that is neither too high nor too low. However, the posture of the fuel supply pump attached to the engine varies depending on the vehicle, and it is not realistic to prepare a fuel supply pump having a different position of the communication hole for each vehicle.

The present invention has been made in view of the above problems, and a fuel capable of expanding the allowable range of the attitude of the fuel supply pump that can suppress the leakage of fuel to the outside of the fuel supply pump while being attached to the engine. The purpose is to provide a feed pump.

In order to solve the above problems, according to a certain aspect of the present invention, the fuel supply pump provided in the fuel supply system of the engine has a camshaft supported by a shaft hole and an insertion portion into which the camshaft is inserted. It has a first seal portion and a second seal portion provided between the insertion member, the inner peripheral surface of the insertion portion, and the outer peripheral surface of the camshaft, and arranged at intervals in the axial direction of the camshaft. A seal member and a communication hole that opens to the inner peripheral surface of the insertion portion and communicates the insertion portion to the outside of the fuel supply pump are provided, and the first seal portion seals the fuel in the fuel supply pump and the first seal portion is provided. The seal portion 2 seals the lubricating oil from the outside of the fuel supply pump, and the seal member is provided below the space between the first seal portion and the second seal portion, and at least the opening of the communication hole. A fuel supply pump is provided that has a fuel reservoir that stores fuel at a higher position.

As described above, according to the present invention, it is possible to expand the permissible range of the posture of the fuel supply pump that can suppress the leakage of fuel to the outside of the fuel supply pump while it is attached to the engine.

It is explanatory drawing which shows the structural example of the fuel supply system to which the fuel supply pump which concerns on this embodiment can be applied. It is a partial cross-sectional view which shows the structural example of the fuel supply pump which concerns on this embodiment. It is explanatory drawing which shows the structural example of the seal member which concerns on this embodiment. It is sectional drawing which shows the structural example of the fuel supply pump which concerns on this embodiment. It is explanatory drawing which shows the state that the fuel is stored in the fuel storage part. It is explanatory drawing which shows the reference example which does not have a fuel storage part. It is explanatory drawing which shows another reference example which does not have a fuel storage part. It is explanatory drawing which shows the degree of freedom of arrangement of a communication hole.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

<1. Overall configuration of engine fuel supply system>
FIG. 1 shows an example of the overall configuration of the fuel supply device 100 of the engine including the fuel supply pump 5 according to the present embodiment. The fuel supply device 100 shown in FIG. 1 is a device that supplies fuel to an injector 13 provided in a cylinder of a diesel engine. The fuel supply device 100 includes a fuel tank 1, a low-pressure pump 2, a fuel supply pump 5, a common rail 10, and an injector 13. Each component is connected by a fuel passage.

The low-pressure pump 2 supplies low-pressure fuel to the pressurizing chamber 5a of the fuel supply pump 5 via the low-pressure fuel passages 18a and 18b. The low-pressure pump 2 may be a mechanical gear pump driven by utilizing the driving force of an engine, or may be an electric pump driven by a current supplied from a battery. A main filter 4 for collecting foreign matter in the fuel is provided in the middle of the low-pressure fuel passage 18a that guides the low-pressure fuel to the fuel supply pump 5. Further, the low pressure fuel passage 18a is provided with a pressure sensor 21 and a temperature sensor 25.

The low-pressure fuel sent into the fuel supply pump 5 once flows into the cam chamber 16 and is further sent from there to the pressurizing chamber 5a via the low-pressure fuel passage 18b. A flow control valve 8 is provided in the middle of the low-pressure fuel passage 18b. The drive of the flow rate control valve 8 is controlled by an electronic control unit (ECU) 40, and the flow rate of low-pressure fuel sent to the pressurizing chamber 5a is adjusted according to the required common rail pressure and fuel injection amount. The flow rate control valve 8 can be, for example, an electromagnetically proportional flow rate control valve.

The low-pressure fuel flow path 18b on the upstream side of the flow control valve 8 is provided with a pressure adjusting valve 14 arranged in parallel with the flow control valve 8. A fuel return path 30a leading to the fuel tank 1 is connected to the pressure regulating valve 14. The pressure regulating valve 14 may be, for example, an overflow valve that is opened when the front-rear differential pressure, that is, the difference between the pressure in the low-pressure fuel passage 18b and the pressure in the fuel return passage 30a exceeds a predetermined value. .. A pressure sensor 23 is provided in the fuel return passage 30a.

The low-pressure fuel whose flow rate is adjusted by the flow rate control valve 8 is introduced into the pressurizing chamber 5a via the fuel suction valve 6. The low-pressure fuel in the pressurizing chamber 5a is pressurized by the plunger 7 that moves forward and backward by the rotation of the cam 15, and is pumped to the common rail 10 via the fuel discharge valve 9 and the high-pressure fuel passage 37.

The common rail 10 stores high-pressure fuel pumped from the fuel supply pump 5 and supplies the high-pressure fuel to the injector 13 connected via the high-pressure fuel passage 39. A rail pressure sensor (not shown) and a pressure control valve 12 are attached to the common rail 10. The drive of the pressure control valve 12 is controlled by the control device 40, and the amount of fuel discharged from the common rail 10 is adjusted so that the value detected by the rail pressure sensor becomes the required common rail pressure. The pressure control valve 12 can be, for example, an electromagnetically proportional flow rate control valve. The fuel discharged by the pressure control valve 12 returns to the fuel tank 1 via the fuel return passage 30b.

The injector 13 connected to the common rail 10 is driven by an electronic control device 40, and injects high-pressure fuel supplied from the common rail 10 into the cylinder of the engine. As the injector 13, for example, a known electromagnetically controlled injector or a piezo injector is used.

Here, in the example of the fuel supply device 100 of the present embodiment, a part of the low-pressure fuel that has flowed into the cam chamber 16 permeates each part in the fuel supply pump 5 and is also used as a lubricant. A camshaft (not shown) to which the cam 15 for driving the fuel supply pump 5 is fixed is supported by a bearing provided in the pump housing. The sliding portions 17a and 17b between the camshaft and the bearing communicate with the fuel return passage 30a, and the difference between the pressure in the cam chamber 16 and the pressure in the fuel return passage 30a is maintained at a predetermined size. A part of the low pressure fuel permeates the sliding portions 17a and 17b. As a result, the fuel functions as a lubricant, and the lubricity of the sliding portions 17a and 17b is ensured.

<2. Configuration example of fuel supply pump>
FIG. 2 shows an example of a specific configuration of the fuel supply pump 5. The fuel supply pump 5 moves forward and backward by the rotation of the pump housing 51, the cylinder head 52 provided with a fuel suction valve and a fuel discharge valve (not shown), the camshaft 55 to which the cam 15 is fixed, and the cam 15. It includes a tappet structure 53 that moves the plunger (not shown) forward and backward. In the fuel supply pump 5, the fuel that has flowed into the pressurizing chamber through the fuel intake valve is pressurized by the plunger in the pressurizing chamber and pumped to the common rail via the fuel discharge valve. In FIG. 2, the above-mentioned flow control valve 8 and pressure adjusting valve 14 are not shown.

The pump housing 51 is formed so as to extend in the axial direction of the camshaft 55, and has a shaft support hole 51a and a flange support hole 51b that are provided coaxially and continuously in the axial direction. The region between the shaft support hole 51a and the flange support hole 51b forms the cam chamber 16. The cam chamber 16 is opened with a columnar space 51c in which the tappet structure 53 and a plunger (not shown) are housed.

The shaft support hole 51a rotatably supports one end side of the camshaft 55 via a bearing 57a. The flange member 61 is inserted into the flange support hole 51b and fixed. The flange member 61 has a shaft support hole 61a and an insertion portion 61b provided coaxially and continuously in the axial direction. The shaft support hole 61a and the insertion portion 61b are provided coaxially with the flange support hole 51b. In the present embodiment, the flange member 61 corresponds to the insertion member in the present invention. The shaft support hole 61a rotatably supports the other end side of the camshaft 55 via the bearing 57b. That is, one end side of the camshaft 55 is supported by the shaft support hole 51a of the pump housing 51, and the other end side is supported by the shaft support hole 61a of the flange member 61.

The flange member 61 is adjacent to an engine (not shown) on the opposite side of the fuel supply pump 5. The engine-side end of the camshaft 55 inserted into the insertion portion 61b of the flange member 61 is inserted into the engine. Lubricating oil for ensuring the lubricity of various sliding portions formed in the engine is supplied to the inside of the engine facing the insertion portion 61b. The lubricating oil for an engine is different from the one that uses fuel as a lubricant, and a lubricating oil having a higher viscosity than the fuel is used. A communication hole 67 is provided between the inner peripheral surface of the insertion portion 61b of the flange member 61 located on the engine side and the outer peripheral surface of the flange member 61. A small diameter portion 55a provided at the other end of the camshaft 55 is arranged in the insertion portion 61b. A seal member 70 is provided between the inner peripheral surface of the insertion portion 61b and the outer peripheral surface of the small diameter portion 55a of the camshaft 55.

The seal member 70 has a first seal portion 73a that seals the fuel in the fuel supply pump 5, and a second seal portion 73b that seals the lubricating oil from the engine side. The first seal portion 73a and the second seal portion 73b are provided so as to be spaced apart from each other in the axial direction of the camshaft 55. The first seal portion 73a and the second seal portion 73b are connected by a connecting portion 75 at the outer peripheral portion. A space 79 surrounded by the connecting portion 75 is formed between the first sealing portion 73a and the second sealing portion 73b.

The space 79 is defined by the first seal portion 73a, the second seal portion 73b, the inner peripheral surface of the connecting portion 75, and the outer peripheral surface of the small diameter portion 55a of the camshaft 55. A hole 77 is formed in the connecting portion 75 that connects the first sealing portion 73a and the second sealing portion 73b. Further, a gap 63 is formed between the outer peripheral surface of the connecting portion 75 of the seal member 70 and the inner peripheral surface of the insertion portion 61b of the flange member 61. The communication hole 67 provided in the flange member 61 opens in the gap 63. As a result, the space 79 communicates with the communication hole 67 through the hole portion 77 and the gap 63. In the fuel supply pump 5 according to the present embodiment, the seal member 70 is attached to the small diameter portion 55a of the camshaft 55, but the seal member 70 is sealed at a position different from that of the small diameter portion 55a, such as when the small diameter portion 55a is not provided. The member 70 may be mounted on the camshaft 55.

FIG. 3 is an explanatory view showing a configuration example of the seal member 70, and shows a perspective view of a half body of the seal member 70 cut in the axial direction. In the illustrated seal member 70, the first seal portion 73a and the second seal portion 73b are each formed in a U-shaped cross section. The first seal portion 73a and the second seal portion 73b are arranged at intervals from each other so that the bottoms of the U-shape face each other. The U-shaped bottom of the first seal portion 73a and the U-shaped bottom of the second seal portion 73b are connected by a connecting portion 75 at the outer peripheral portion. A space 79 having a U-shaped cross section opened in the axial direction is formed by the first seal portion 73a, the second seal portion 73b, and the connecting portion 75.

By mounting the seal member 70 on the outer peripheral surface of the camshaft 55, the inner peripheral surfaces of the first seal portion 73a and the second seal portion 73b come into contact with the outer peripheral surface of the camshaft 55, and the space 79 becomes the camshaft. Closed by 55. The seal member 70 has a hole portion 77 in the connecting portion 75 that communicates the space 79 with the outer peripheral portion of the seal member 70. The outer peripheral surface of the connecting portion 75 faces the gap 63 formed by the inner peripheral surface of the insertion portion 61b of the flange member 61 and the outer peripheral surface of the sealing member 70. Therefore, the space 79 communicates with the gap 63 through the hole 77.

The seal member 70 shown in FIG. 3 may be a molded product of a resin material such as PTFE (Polytetrafluoroethylene). The seal member 70 made of PTFE is excellent in low temperature resistance and excellent in slidability of the camshaft 55. However, the constituent material of the seal member 70 is not limited to PTFE. Further, the seal member 70 does not have to be an integrally molded molded body, and may be a structure in which a plurality of molded bodies are joined. Further, the seal member 70 may be a composite in which a molded body such as PTFE is joined to a base plate made of a metal plate or the like.

FIG. 4 is a cross-sectional view of the I-I cross section in FIG. 2 viewed in the direction of the arrow, showing a state in which the fuel supply pump 5 is attached to the engine and mounted on the vehicle. FIG. 4 shows a cross section of the connecting portion 75 of the seal member 70. When the fuel supply pump 5 is attached to the engine and mounted on the vehicle, the communication hole 67 of the flange member 61 is provided so as to open at the lowermost portion of the inner peripheral surface of the insertion portion 61b in the vertical direction. Further, the hole portion 77 of the seal member 70 is provided at a position other than the lowermost portion in the vertical direction of the connecting portion 75. In the example shown in FIG. 4, the seal member 70 has two holes 77 provided on both the left and right sides of the connecting portion 75 with the lowermost portion in the vertical direction interposed therebetween. Therefore, a fuel storage unit 81 capable of storing fuel is formed below the space 79.

The position of the upper end of the fuel storage unit 81 capable of storing fuel is defined by the hole portion 77. That is, when the liquid level of the fuel stored in the fuel storage unit 81 reaches the hole portion 77, the fuel flows out into the gap 63 through the hole portion 77. In the example shown in FIG. 4, the position H1 of the upper end of the fuel storage portion 81 is set to a position lower than the position H2 of the seal portion formed by the second seal portion 73b and the small diameter portion 55a of the camshaft 55. ing. Therefore, the position of the hole portion 77 is set so that the fuel stored in the fuel storage portion 81 does not reach the seal portion formed by the small diameter portion 55a of the camshaft 55 and the second seal portion 73b. It is set.

<3. Action of seal member>
Next, the operation of the seal member 70 will be described. In the fuel supply pump 5 according to the present embodiment, the low-pressure fuel flowing into the cam chamber 16 functions as a lubricant between the cam 15 and the tappet structure 53. Further, a part of the low-pressure fuel in the cam chamber 16 also permeates into the columnar space 51c, and the sliding portion between the inner peripheral surface of the space 51c and the outer peripheral surface of the tappet structure 53 and the plunger (not shown) It spreads over sliding parts and functions as a lubricant. Further, a part of the low-pressure fuel in the cam chamber 16 permeates into the sliding portions 17a and 17b between the camshaft 55 and the bearings 57a and 57b, and functions as a lubricant.

When the fuel supply pump 5 is being driven during engine operation, the camshaft 55 rotates so that the inner peripheral surfaces of the first seal portion 73a and the second seal portion 73b of the seal member 70 and the camshaft 55 An air pumping action occurs in the seal portion formed by the small diameter portion 55a. The air pumping action means an action of sucking air into the seal portion through the communication hole 67, the gap 63, and the hole portion 77 by the rotation of the camshaft 55.

Specifically, in the seal portion formed by the first seal portion 73a, air is sucked toward the cam chamber 16 side inside the fuel supply pump 5. Further, in the seal portion formed by the second seal portion 73b, air is sucked toward the inside of the engine. When such an air pumping action occurs, a negative pressure is formed in the space 79 of the seal member 70, and the air outside the fuel supply pump 5 enters the space 79 through the hole 77, the gap 63, and the communication hole 67. be introduced. Therefore, the leakage of fuel in the fuel supply pump 5 from the seal portion formed by the first seal portion 73a and the small diameter portion 55a of the camshaft 55, and the second seal portion 73b and the small diameter portion 55a of the camshaft 55 The sealing property against leakage of engine lubricating oil from the sealing portion formed by the engine is further enhanced. In the state where the driving of the fuel supply pump 5 is stopped when the engine is stopped, the above-mentioned air pumping action does not occur.

Here, if a foreign substance invades the seal portion formed by the first seal portion 73a and the second seal portion 73b, or if the seal portion deteriorates due to the invasion of the foreign matter, the sealing property of the seal portion may deteriorate. There is. In the case where the sealing property is significantly deteriorated and the engine is stopped and the air pumping action cannot be expected, the fuel in the fuel supply pump 5 having a viscosity lower than that of the lubricating oil of the engine is the first sealing portion. It is conceivable that the seal portion formed by the 73a and the small diameter portion 55a of the camshaft 55 may seep into the space 79 between the first seal portion 73a and the second seal portion 73b. At this time, in the fuel supply pump 5 according to the present embodiment, the condensed fuel is stored in the fuel storage unit 81 formed in the lower part of the space 79, so that the leakage of the fuel to the outside of the fuel supply pump 5 is suppressed. Fuel.

FIG. 5 shows how the fuel F is stored in the fuel storage unit 81 formed in the lower part of the space 79 of the seal member 70 of the fuel supply pump 5 shown in FIG. The fuel that has exuded and condensed in the space 79 is stored in the fuel storage unit 81, so that it is difficult for the fuel to leak to the outside of the fuel supply pump 5 through the communication hole 67. In this case, the stored fuel is vaporized with the passage of time or an increase in temperature, and is easily discharged to the outside of the fuel supply pump 5 in a gaseous state through the holes 77, the gaps 63, and the communication holes 67. Further, when the fuel is vaporized and held in the space 79, when the engine is started and the driving of the fuel supply pump 5 is started to cause an air pumping action, the fuel is supplied into the fuel supply pump 5. It becomes easy to be inhaled.

On the other hand, FIG. 6 is an explanatory diagram showing a reference example having no fuel storage unit. When the space 179 between the first seal portion and the second seal portion does not have the fuel storage portion, it seeps out from the seal portion formed by the first seal portion 173a and the cam shaft 155 and condenses. The fuel leaks to the outside of the fuel supply pump 5 through the communication hole 167 that opens in the lower part of the space 179. In order to avoid leakage of fuel to the outside of the fuel supply pump 5 without providing a fuel storage portion, a communication hole 167 for sucking air may be provided above the insertion portion 161b of the flange member 161 instead of at the bottom. Conceivable.

FIG. 7 is an explanatory view showing a reference example in which the communication hole 167 is provided above the insertion portion 161b of the flange member 161. In the reference example shown in FIG. 7, the fuel liquid that is stored by the fuel that has exuded and condensed from the seal portion formed by the first seal portion 173a and the camshaft 155 continues to be stored in the space 179. The surface reaches the seal portion formed by the second seal portion 173b and the camshaft 155. Therefore, there is a possibility that the fuel is sucked into the engine side and the lubricating oil is diluted due to the pumping action generated when the engine is started and the driving of the fuel supply pump 5 is started.

On the other hand, as shown in FIG. 5, in the fuel supply pump 5 according to the present embodiment, the hole 77 is maintained in the open state even when the fuel is stored in the fuel storage 81. Fuel. Therefore, even when the engine is started and the fuel supply pump 5 starts to be driven, air is sucked from the outside of the fuel supply pump 5 through the holes 77, the gaps 63, and the communication holes 67 due to the pumping action of the air. Is less likely to be inhibited.

Further, the position H1 at the upper end of the fuel storage portion 81 is lower than the position H2 of the seal portion formed by the second seal portion 73b and the small diameter portion 55a of the camshaft 55. Therefore, even if a pumping action occurs when the fuel supply pump 5 is driven, it is possible to prevent the fuel stored in the fuel storage unit 81 from being sucked into the engine side. Therefore, it is possible to reduce the possibility that the viscosity of the lubricating oil of the engine will decrease.

Further, as shown in FIG. 8, since the seal member 70 has the fuel storage portion 81 in the lower part of the space 79, the opening position of the communication hole 67 that opens to the insertion portion 61b of the flange member 61 is determined by the hole portion 77. The degree of freedom in arranging the communication hole 67 is increased as long as it is located below the specified position of the upper end of the fuel storage unit 81. That is, even if the posture of the fuel supply pump 5 attached to the engine differs depending on the vehicle type or the like, the fuel supply pump 5 can be provided by matching the arrangement of the seal member 70 (rotational phase around the axis of the camshaft 55). It is possible to suppress the leakage of fuel to the outside. In addition, it is possible to prevent the fuel stored in the fuel storage unit 81 from being sucked into the engine. That is, fuel supply capable of suppressing fuel leakage to the outside even when a common fuel supply pump is used without preparing a fuel supply pump at different positions of the communication holes 67 for all vehicle models. The allowable range of the posture of the pump 5 can be expanded.

Further, the fuel supply pump 5 according to the present embodiment can be configured only by replacing the first seal portion and the second seal portion provided in the conventional fuel supply pump with the seal member 70. .. Therefore, it is possible to obtain the fuel supply pump 5 capable of suppressing the leakage of fuel to the outside while suppressing the increase in the production cost.

<4. Effect>
As described above, in the fuel supply pump 5 according to the present embodiment, at least the opening of the communication hole 67 of the flange member 61 below the space 79 between the first seal portion 73a and the second seal portion 73b. A fuel storage unit 81 for storing fuel at a position higher than the unit is provided. Therefore, it is possible to prevent the condensed fuel that has exuded from the inside of the fuel supply pump 5 from leaking to the outside of the fuel supply pump 5 through the seal portion formed by the first seal portion 73a and the camshaft 55. can do.

Further, the position of the upper end of the fuel storage portion 81 is set below the position of the seal portion formed by the second seal portion 73b and the outer peripheral surface of the camshaft 55, whereby the fuel supply pump 5 is set. When the fuel is driven to pump air, the introduction of the fuel supply pump 5 into the space 79 outside the air is less likely to be hindered. Further, the position of the upper end of the fuel storage portion 81 is set below the position of the seal portion formed by the second seal portion 73b and the outer peripheral surface of the camshaft 55, so that the fuel storage portion 81 has a position. It is suppressed that the stored fuel is sucked into the engine side through the seal portion formed by the second seal portion 73b and the camshaft 155. Therefore, the dilution of the lubricating oil inside the engine can be suppressed.

Then, the fuel supply pump 5 according to the present embodiment appropriately adjusts the position of the seal member 70 around the axis of the camshaft 55, so that the fuel can be supplied to the outside of the fuel supply pump 5 in a state of being attached to the engine. The permissible range of the posture of the fuel supply pump 5 capable of suppressing leakage can be expanded. Therefore, the shareable range of the fuel supply pump 5 can be expanded without preparing the fuel supply pump 5 in which the position of the communication hole 67 is different for each vehicle type.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

For example, in the fuel supply pump 5 according to the above embodiment, the position of the upper end of the fuel storage portion 81 is defined by providing the seal member 20 with two holes 77, but the present invention is not limited to this example. .. There may be only one hole 77 that defines the position of the upper end of the fuel storage 81. Alternatively, for example, by providing four hole portions 77 every 90 degrees around the axis, the degree of freedom in assembling the seal member 20 to the camshaft 55 can be increased. The hole 77 may be a slit.

Further, in the fuel supply pump 5 according to the above embodiment, the first seal portion 73a and the second seal portion 73b are connected by the connecting portion 75 over the entire circumference to form the fuel storage portion 81. At the same time, the position of the upper end of the fuel storage portion 81 is defined by providing the hole portion 77 in the connecting portion 75, but the present invention is not limited to this example. For example, the fuel storage portion can be formed by connecting the first seal portion 73a and the second seal portion 73b only at the lower part of the space 79. Even when a seal member having such a configuration is adopted, the same effect as that of the fuel supply pump 5 according to the above embodiment can be obtained.

5 Fuel supply pump 51 Pump housing 55 Camshaft 55a Small diameter 61 Flange member (insertion member)
63 Gap 67 Communication hole 70 Seal member 73a First seal part 73b Second seal part 75 Connection part 77 Hole part 79 Space 81 Fuel storage part

Claims (5)

In the fuel supply pump installed in the fuel supply system of the engine
The camshaft supported by the shaft hole and
An insertion member having an insertion portion into which the camshaft is inserted,
A seal having a first seal portion and a second seal portion provided between the inner peripheral surface of the insertion portion and the outer peripheral surface of the camshaft and arranged at intervals in the axial direction of the camshaft. Members and
A communication hole that opens to the inner peripheral surface of the insertion portion and communicates the insertion portion to the outside of the fuel supply pump is provided.
The first seal portion seals the fuel in the fuel supply pump.
The second seal portion seals the lubricating oil from the outside of the fuel supply pump.
The seal member is provided below the space between the first seal portion and the second seal portion, and has a fuel storage portion that stores fuel at least at a position higher than the opening of the communication hole. , Fuel supply pump. The fuel supply pump according to claim 1, wherein the position of the upper end of the fuel storage portion is lower than the position of the seal portion formed by the second seal portion and the camshaft. The fuel supply pump according to claim 1 or 2, wherein the fuel storage portion is formed by connecting the first seal portion and the second seal portion at least in the lower part of the space. The seal member is
A connecting portion that connects the first sealing portion and the second sealing portion over the entire circumference of the camshaft to define the space on the inner peripheral portion.
It has a hole or a slit that communicates the space with the outside of the seal member.
The fuel storage section is the lower part of the space defined by the connecting section.
The fuel supply pump according to any one of claims 1 to 3, wherein the position of the upper end of the fuel storage portion is defined by the hole portion or the slit. The camshaft is rotationally driven by the driving force of the engine.
The fuel supply pump according to any one of claims 1 to 4, wherein the second seal portion seals the lubricating oil from the engine side.

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