JP3882907B2 - High pressure supply pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-pressure supply pump used for an internal combustion engine (hereinafter, the internal combustion engine is referred to as an “engine”).
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent No. 3077738, a high-pressure supply pump driven by a pump cam attached to an engine camshaft is known. By driving the high-pressure supply pump by a pump cam attached to the camshaft, it is not necessary to incorporate a cam in the high-pressure supply pump. Therefore, the high pressure supply pump can be reduced in size, and there is an advantage that the space required for mounting the high pressure supply pump is reduced.
[0003]
[Problems to be solved by the invention]
However, in an engine equipped with continuous phase control means for changing the phase of the camshaft relative to the drive shaft of the engine, when the high pressure supply pump is driven by the camshaft equipped with the continuous phase control means, In addition to the driving torque of the exhaust valve or the intake valve, the driving torque of the high-pressure supply pump acts. At this time, the driving torque of the high-pressure supply pump acting on the camshaft becomes the operating load of the continuous phase control means. Therefore, there is a problem that the operation of the continuous phase control means becomes unstable due to fluctuations in the driving torque of the high-pressure supply pump.
[0004]
The phase of the variable camshaft is advanced or retarded with the operation of the continuous phase control means. Along with this, the pump cam driven by the variable camshaft is also advanced or retarded. Therefore, it is necessary to perform control for changing the operation characteristics of the high-pressure supply pump in accordance with the operation of the continuous phase control means.
[0005]
Furthermore, in the case of an engine having a plurality of cylinder heads such as a V-type engine, the total number of camshafts does not match the total number of high-pressure supply pumps. For example, in the case of a V-type DOHC engine, each cylinder head is equipped with an intake cam shaft and an exhaust cam shaft, and the total number of cam shafts is four, whereas the high-pressure supply pump is driven by one of them. . In this case, the load is different between the continuous phase control means mounted on the camshaft that drives the high-pressure supply pump and the continuous phase control means mounted on another camshaft. Therefore, the operation response period of the continuous phase control means may be different among the cylinder heads. As a result, there is a problem that only the continuous phase control means mounted on the camshaft that drives the high-pressure supply pump has to be enlarged in order to match the operation response period of the continuous phase control means between the cylinder heads. .
[0006]
Therefore, an object of the present invention is to provide a high-pressure supply pump that does not affect the operation of the continuous phase control means.
[0007]
[Means for Solving the Problems]
According to the high pressure supply pump of the first aspect of the present invention, the pump unit is driven by the pump cam. The pump cam rotates together with the sprocket wheel to which the driving force is transmitted from the driving shaft, and transmits the rotational force to the pump unit. Therefore, the pump cam is directly driven by the driving force of the driving shaft transmitted to the sprocket wheel, and the driving torque of the pump portion does not act on the variable cam shaft. Note that. The variable camshaft is a camshaft to which continuous phase control means is mounted among a plurality of camshafts possessed by the engine. Therefore, even when the pump cam and the pump section are provided on the side of the variable cam shaft on which the continuous phase control means is mounted, the operation of the continuous phase control means is not affected.
[0008]
According to the high pressure supply pump of the second aspect of the present invention, the pump cam is formed integrally with the sprocket wheel. Therefore, the number of parts can be reduced.
According to the high pressure supply pump of claim 4 of the present invention, the pump cam is installed between the bearing of the variable camshaft and the engaging portion. A transmission means for transmitting a driving force to the sprocket wheel is engaged with the engaging portion. By installing a pump cam between the bearing and the engaging part, and reducing the distance between the bearing and the engaging part, the axial position of the variable camshaft by the driving force acting on the engaging part from the transmission means Deviation can be reduced.
[0009]
According to the high pressure supply pump according to claim 3 of the present invention, the pump cam is formed on the sprocket wheel and another member. Therefore, the pump cam can be made of a material different from that of the sprocket wheel, and the material of the pump cam can be freely selected. Since the pump cam is subjected to a large load from the pump portion, there is a risk that the wear will be severe compared to the sprocket wheel. By making the sprocket wheel and the pump cam separately, only the pump cam can be made of a highly wear-resistant material.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plurality of examples showing embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 shows a main part of an engine equipped with a high-pressure supply pump according to a first embodiment of the present invention.
[0011]
The high-pressure supply pump 1 is mounted on a chain cover 7 mounted on the engine head cover 2. Inside the head cover 2 is accommodated a camshaft for opening and closing an intake valve or an exhaust valve (not shown). A camshaft 10 shown in FIG. 1 is an exhaust camshaft that opens and closes an exhaust valve (not shown), and has an exhaust cam (not shown). A valve timing adjusting device (hereinafter referred to as “VVT”) 20 as a continuous phase control means is attached to the end of the camshaft 10. That is, the camshaft 10 is a variable camshaft to which the VVT 20 is mounted. The camshaft 10 has a sliding portion 11 supported by a bearing 3 formed integrally with the head cover 2, and the camshaft 10 is rotatably supported by the head cover 2. The engine on which the high-pressure supply pump 1 is mounted may be either a gasoline engine or a diesel engine.
[0012]
A pulley 50 is installed on the outer peripheral side of the camshaft 10. The pulley 50 is free to rotate with respect to the camshaft 10. The pulley 50 has a sprocket wheel 51, a pump cam 52, and a flange 53. The sprocket wheel 51, the pump cam 52, and the flange 53 constituting the pulley 50 are integrally formed. As shown in FIG. 2, the sprocket wheel 51 is formed on a disc and has an engaging portion 54 on the outer peripheral portion. The timing belt 4 as a transmission means is engaged with the engaging portion 54. The transmission means is not limited to the timing belt, and a timing chain or the like may be used. The timing belt 4 is engaged with a driving shaft of an engine (not shown) on the side opposite to the engaging portion 54. As a result, the driving force of the drive shaft of the engine is transmitted to the sprocket wheel 51 via the timing belt 4. As shown in FIG. 1, when the driving force of the drive shaft is transmitted to the sprocket wheel 51, the entire pulley 50 rotates together with the sprocket wheel 51. Therefore, the rotation of the pulley 50 causes the pump cam 52 and the flange 53 to rotate.
[0013]
The pump cam 52 is installed between the sprocket wheel 51 and the flange 53. The pump cam 52 has a cam profile 55 as shown in FIG. The lifter 61 of the pump unit 60 is in contact with the cam profile 55, and the lifter 61 is reciprocated in the vertical direction in FIGS. 1 and 2 as the pump cam 52 rotates.
[0014]
The high-pressure supply pump 1 includes a pump cam 52 and a pump unit 60. The pump unit 60 has an electromagnetic valve unit 62. The pump unit 60 has a plunger (not shown) that is reciprocated in the vertical direction of FIGS. 1 and 2 together with the lifter 61. The plunger is supported by the housing 63 of the pump unit 60 so as to be able to reciprocate. A pressure chamber (not shown) is formed together with the housing 63 at the end of the plunger opposite to the lifter. The electromagnetic valve unit 62 adjusts the flow of fuel flowing into or out of the pressurizing chamber (not shown).
[0015]
When the lifter 61 that contacts the cam profile 55 is lowered in the camshaft 10 direction as the pump cam 52 is rotated, the plunger (not shown) is lowered in the camshaft 10 direction together with the lifter 61. At this time, the electromagnetic valve portion 62 is opened, and fuel is sucked into a pressurizing chamber (not shown) by the lowering of the plunger. Since the solenoid valve portion 62 is opened at the beginning of the lifter 61 ascending, the fuel sucked into the pressurizing chamber as the plunger rises is discharged to the outside of the high-pressure supply pump 1 via the solenoid valve portion 62. The When the plunger reaches a position corresponding to a predetermined fuel discharge amount, the solenoid valve portion 62 is closed, and the plunger further rises together with the lifter 61, whereby the fuel pressure in the pressurizing chamber rises. When the pressure of the fuel in the pressurizing chamber reaches a predetermined pressure, a check valve (not shown) is opened, and high-pressure fuel is discharged from the discharge port 64.
[0016]
As shown in FIG. 1, the VVT 20 includes a housing 21 and a vane 30. The housing 21 is fixed integrally with the pulley 50 by a bolt 5. Therefore, the housing 21 can rotate together with the pulley 50. On the other hand, the vane 30 is fixed integrally with the camshaft 10 by bolts 6. Therefore, the vane 30 can rotate together with the camshaft 10. As shown in FIG. 3, the vane 30 is accommodated in the housing 21. The vane 30 is biased in the advance direction by the spring 22. A hydraulic chamber is formed between the vane 30 and the housing 21, and the hydraulic chamber is divided into a retard chamber 32 and an advance chamber 33 by a blade portion 31 of the vane 30. By supplying hydraulic oil to the retard chamber 32 or the advance chamber 33, the vane 30 rotates relative to the housing 21. When the housing 21 and the vane 30 rotate relatively, the phase of the driving force transmitted from the driving shaft to the camshaft 10 rotating integrally with the vane 30 via the housing 21 rotating integrally with the pulley 50 is increased. Be changed.
[0017]
As shown in FIG. 1, one of the vane portions 31 of the vane 30 is provided with a stopper pin 40 for fixing the position of the vane 30 to a predetermined advance position (for example, the most advanced position) when starting the engine. Has been. The stopper pin 40 is inserted into a hole 34 formed in the blade 31 and is urged toward the flange 53 by a spring 41. When the end of the stopper pin 40 is fitted into the stopper hole 56 formed in the flange 53, the vane 30 is locked with respect to the housing 21. A stepped portion 42 is formed in the stopper pin 40, and the hydraulic pressure of the hydraulic oil acts on the stepped portion 42, so that the stopper pin 40 comes out of the stopper hole 56 against the urging force of the spring 41. Thereby, the locked state of the housing 21 and the vane 30 is released.
[0018]
The driving force of the engine drive shaft is transmitted to the sprocket wheel 51 via the timing belt 4. Thereby, the pulley 50 is rotationally driven. As the pulley 50 rotates, the pump cam 52 and the flange 53 that are integrally formed also rotate. As the pump cam 52 rotates, the pump unit 60 is driven. On the other hand, when the flange 53 rotates, the housing 21 integrated with the flange 53 rotates. The rotational force of the housing 21 is transmitted to the vane 30. Then, the camshaft 10 integrated with the vane 30 is rotationally driven. As a result, the driving force of the drive shaft of the engine is transmitted to the camshaft 10 via the VVT 20.
[0019]
As described above, according to the high-pressure supply pump 1 according to the first embodiment of the present invention, the pump unit 60 is driven by the pump cam 52 that rotates together with the pulley 50. The pulley 50 is driven by the drive shaft of the engine via the timing belt 4. Therefore, the pump unit 60 is directly driven by the driving force transmitted from the drive shaft via the timing belt 4. Thereby, the drive torque from the pump part 60 does not act on the camshaft 10. Therefore, even when the pump cam 52 and the pump unit 60 are installed on the camshaft 10 side where the VVT 20 is mounted, the influence on the operation of the VVT 20 can be reduced. Further, even when the engine has a plurality of camshafts, there is no difference between the drive torques acting on the VVT 20 and each camshaft, and each camshaft can be operated stably.
[0020]
In the first embodiment, the sprocket wheel 51 is located between the bearing 3 of the camshaft 10 and the pump cam 52. Thereby, the sprocket wheel 51 is disposed in the vicinity of the bearing 3. Therefore, an increase in the bending moment of the camshaft 10 due to the tension of the timing belt 4 can be suppressed. Further, the pulley 50 is integrally formed with the sprocket wheel 51, the pump cam 52 and the flange 53. Therefore, the number of parts can be reduced.
[0021]
(Second embodiment)
A high-pressure supply pump according to a second embodiment of the present invention is shown in FIG. Components that are substantially the same as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the second embodiment, the arrangement of the sprocket wheel 71, the pump cam 72, and the flange 73 of the pulley 70 is different from the first embodiment. In the second embodiment, a sprocket wheel 71 is disposed on the outer peripheral side of a flange 73 fixed to the housing 21 of the VVT 20. That is, the sprocket wheel 71 and the flange 73 are arranged at the same site. The pulley 70 has a flange 73 on which a sprocket wheel 71 is disposed and a pump cam 72. The sprocket wheel 71 disposed on the outer peripheral side of the flange 73 has an engaging portion 74 that engages with the timing belt 4 at the radially outer end portion. The pump cam 52 forms an integral pulley 70 together with a flange 73 on which the sprocket wheel 71 is disposed. The pulley 70 is free in the rotational direction with respect to the camshaft 10 as in the first embodiment.
[0022]
In the second embodiment, the pump cam 72 is rotated by the driving force transmitted from the drive shaft to the sprocket wheel 71, and the pump unit 60 is driven by the rotation of the pump cam 72. Therefore, as in the first embodiment, the driving torque of the pump unit 60 does not affect the operation of the VVT 20.
In the second embodiment, the length of the pulley 70 in the axial direction is shortened by disposing the sprocket wheel 71 on the flange 73. Therefore, the VVT 20 can be reduced in size, and the space required for mounting these can be reduced.
[0023]
(Third embodiment)
A high pressure supply pump according to a third embodiment of the present invention is shown in FIG. Components that are substantially the same as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
The third embodiment is a modification of the second embodiment. In the third embodiment, the pulley 80 includes a pulley body 81 and a pump cam 82. The pulley body 81 is integrally formed with a flange 84 on which a sprocket wheel 83 is disposed. The pump cam 82 is formed separately from the pulley body 81, and is fixed by welding or the like after being press-fitted or inserted into the pulley body 81, for example. That is, the pump cam 82 is free to rotate in the rotational direction with respect to the camshaft 10 on the outer peripheral side of the camshaft 10 together with the pulley body 81.
[0024]
In the third embodiment, by making the pump cam 82 separate from the pulley body 81, only the pump cam 82 that receives a large load from the pump portion 60 can be formed of a material with high wear resistance. For example, the pulley body 81 can be formed of a sintered material that can be easily processed and molded, and the pump cam 82 can be formed of high strength chromium molybdenum steel or the like. Therefore, the life of the pump cam 82 can be extended.
[0025]
(Modification)
In the above embodiments, the example in which the sprocket wheel, the pump cam and the pulley having the flange are integrated or only the pump cam is separated has been described. However, the present invention may be modified as follows.
Divide the pulley into flange, pump cam and sprocket wheel. By dividing these, even when the pump cam is located between the sprocket wheel and the flange, the pump cam can be formed of a material different from that of the sprocket wheel and the flange, and the life of the pump cam can be extended.
[0026]
In the above-described embodiments of the present invention, the case where one high-pressure supply pump according to the present invention is installed on the camshaft that drives the exhaust valve has been described. However, not only the exhaust valve but also one or more high-pressure supply pumps may be installed on the camshaft that drives the intake valve and each camshaft that drives the intake valve and the exhaust valve.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a main part of an engine equipped with a high-pressure supply pump according to a first embodiment of the present invention.
2 is an arrow view seen from the direction of arrow II in FIG.
3 is a schematic diagram showing a VVT of an engine equipped with a high-pressure supply pump according to a first embodiment of the present invention, as viewed from the direction of arrow II in FIG.
FIG. 4 is a schematic view showing a main part of an engine equipped with a high-pressure supply pump according to a second embodiment of the present invention.
FIG. 5 is a schematic view showing a main part of an engine equipped with a high-pressure supply pump according to a third embodiment of the present invention.
[Explanation of symbols]
1 High-pressure supply pump 3 Bearing 4 Timing belt (transmission means)
10 Camshaft 20 VVT (continuous phase control means)
51, 71, 83 Sprocket wheels 52, 72, 82 Pump cams 53, 73, 84 Flange 54, 74 Engagement part 60 Pump part

Claims (4)

An internal combustion engine comprising continuous phase control means for changing a phase of a camshaft for opening and closing an intake valve or an exhaust valve from a drive shaft of the internal combustion engine with respect to the drive shaft, wherein the continuous phase control means is mounted on the camshaft. A high-pressure supply pump that is provided on the variable camshaft and is driven by the driving force of the drive shaft that is transmitted to the variable camshaft via the continuous phase control means,
A pump section for pressurizing and discharging the inhaled fluid;
A pulley that is installed in a rotating state with respect to the variable camshaft , and that transmits a driving force for driving the variable camshaft from the drive shaft to the continuous phase control means;
With
The pulley is
A cylindrical pulley body;
A sprocket wheel provided so as to protrude from the outer peripheral surface of the pulley body to the outer peripheral side, and wherein the driving force is transmitted from the driving shaft ;
A pump cam provided to protrude from the outer peripheral surface of the pulley main body to the outer peripheral side, rotates integrally with the sprocket wheel and the pulley main body , and transmits the rotational force of the sprocket wheel to the pump unit;
A high-pressure supply pump comprising: The high-pressure supply pump according to claim 1, wherein the pump cam is formed integrally with the sprocket wheel and the pulley body . The pump cam is claim 1 Symbol mounting pressure supply pump, characterized in that it is formed in the sprocket wheel and another member. 2. The pump cam is installed between a bearing of the variable cam shaft and an engaging portion to which a transmission means for transmitting a driving force from the driving shaft to the sprocket wheel is engaged. The high pressure supply pump according to any one of claims 1 to 3.

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