JP3227299B2 - Lubrication structure of unit injector drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating structure for a unit injector driving device, and more particularly to a lubricating structure for a unit injector driving device suitable for lubricating a drive system component of a fuel injection device of an internal combustion engine such as a diesel engine.

[0002]

2. Description of the Related Art Heretofore, the following lubrication structures have been known for a device comprising a drive system component of a unit injector (fuel injection device) of an internal combustion engine. FIG. 4 is a front view of a partial cross section of a lubricating structure of a unit injector driving device according to the related art, and FIG. 5 is a cross sectional view of the vicinity of the tip end of the rocker arm in FIG. The unit injector driving device 50 includes a cam 1, a cam follower 2, a push rod 5, a rocker arm 56, an injection seat 57, and a unit injector 8.
Is composed of a substantially hemispherical injection sheet 58, a spring holder 59, and a spring 61. In addition, as a lubricating structure for flowing oil or the like, an oil hole 71 is provided inside a shaft 56a that allows the rocker arm 56 to rotate,
The rocker arm 56 has an oil hole 72 inside, and the injection sheet 58 has an oil hole 74 therethrough. One end of the oil hole 72 is connected to the oil hole 71 via a gap that can be oiled formed between the outer peripheral surface of the shaft 56a and the rocker arm 56, and the other end can communicate with the oil hole 74 when the oil hole 74 is in operation. Is formed.

[0003] With this configuration, the cam follower 2 which is in close contact with the cam 1 converts the rotational movement of the cam 1 rotating in synchronization with the engine rotation into a vertical movement, and transmits this vertical movement to the rocker arm 56 via the push rod 5. I do. Due to the swinging motion of the end 56b of the rocker arm 56, the close injection sheet 58 is pushed down, and the fuel injection plunger (not shown) located below the spring holder 59 via the spring holder 59 while compressing the spring 61. ) To inject high pressure fuel. In this operation, the oil supplied through the oil holes 71 and 72 provides good flat sliding between the end surface 56b of the rocker arm 56 and the flat surface between the injection sheet 58 and the oil hole 74. It has been known that good lubrication between the spherical portion of the injection seat 58 and the spherical concave portion of the spring holder 59 can be obtained by lubrication from the engine, thereby obtaining the reliability and durability of the engine. 4-56980).

Although not disclosed in the above prior art, as shown in FIG. 4, an oil hole 7 in a shaft 56a is provided.
The rocker arm 56 is provided with an oil hole 73 capable of refueling from 1
As shown by the arrow 81, the oil travels along the rocker arm 56 to lubricate the spherical contact portion with the push rod 5, and then flows around the outer periphery of the push rod 5 in the direction of the arrow 82, and the push rod 5
Lubricating the contact portion between the cam follower 2 and the cam follower 2 and flowing to the arrow 83 to lubricate the contact portion between the cam follower 2 and the cam 1.
On the other hand, the rocker arm 56 and the injection seat 58
A portion of the oil that has lubricated the close contact surface 58a and the like flows into the hole of the push rod 5 as indicated by an arrow 84. In addition, a concave portion is formed on the upper surface of the cylinder head where the rocker arm 56 and the like are installed, and oil dripping from the intake valve, the exhaust valve driving rocker arm and the like is collected, and the unit injector, the intake valve, and the exhaust valve driving push rod hole are formed. Let in
Each drive cam follower is lubricated. Further, the contact portion between the cam follower 2 and the cam 1 serving as a high load portion is supplied with oil and lubricated by a lubrication structure (not shown) separately formed on the cam follower 2. With the lubrication structure described above, the drive system components of the unit injector (fuel injection device) of the internal combustion engine are supplied with oil and lubricated.

Next, as another prior art, there is known a sectional structure near the tip of a rocker arm of a lubricating structure of a unit injector driving device as shown in FIG. FIG.
6A shows a state in which the unit injector is not injecting fuel, and FIG. 6B shows a state in which the unit injector is injecting fuel. At the close contact portion between the rocker arm 91 and the injection sheet 92, the cylindrical surface tip portion 91 a of the rocker arm 91 is in close contact with the flat end portion 92 a of the injection sheet 92, and an oil hole 93 is formed in the rocker arm 91. I have.
With this configuration, when the engine is operating, the rocker arm 91
6b swings and slides flat on the front end flat portion 92a of the injection sheet 92, but since the front end portion is cylindrical, the spring 61 is pressed downward as shown in FIG. 6B. Then, the tip 93a of the oil hole 93
Opens to the atmosphere in the engine room. By this opening, the air bleeding of the oil hole 93 is made good, and even when the oil supply pressure is low, oil can be supplied to the contact surface and good lubrication is obtained.

[0006]

However, the above prior art has the following problems. That is, in the former case, in the case of flat surfaces between the end 56b of the rocker arm 56 and the injection sheet 58, since the contact area is large, the generation of galling or the like is prevented by reducing the contact surface pressure. However, because the contact is wide and the adhesion is good, when the engine oil pressure is low due to low speed operation of the engine,
In some cases, the air inside the oil hole 72 is not sufficiently vented, resulting in insufficient oil supply to the contact surface. In addition, when the rise of the oil pressure is delayed at the time of rapid acceleration of the engine, it may be impossible to quickly supply oil to the contact surface due to insufficient air release. Further, a part of the oil supplied to the flat contact portion scatters in the direction of arrow 62 (see FIG. 5) and collides with the inner wall of the cylinder head cover (not shown), which causes a problem of generating noise. . Next, in the latter case where the cylindrical surface and the flat surface are in contact, although good lubrication is obtained, the contact surface pressure is large due to the small contact area, and galling etc. occurs on the contact surface,
There is a problem of insufficient durability.

[0007] Further, regarding lubrication of a contact portion between the cam follower 2 and the cam 1 which becomes a high load portion, an arrow 83 (see FIG. 4)
Good lubrication by lubrication by the flow of oil and lubrication by the cam follower 2's unique lubrication structure.
The oil that accumulates in the recess on the top surface of the cylinder head flows into each push rod hole and lubricates the unit injector, the intake valve, and the cam follower for driving the exhaust valve almost equally, so that the load is larger than that for driving the intake valve and the exhaust valve. In the unit injector driving cam follower portion, lubrication of the contact portion between the cam follower 2 and the cam 1 tends to be insufficient, which may cause a problem in reliability and durability.

The present invention focuses on the problems of the prior art described above, enables good lubrication by appropriate and efficient lubrication of the drive system components of the unit injector, and further reduces noise generation due to scattering and collision of lubricating oil. It is an object of the present invention to provide a lubricating structure of a unit injector driving device capable of preventing the lubrication.

[0009]

In order to achieve the above object, in a lubricating structure for a unit injector driving device according to the present invention, a first invention is directed to a cam, a cam follower for converting a rotational motion of the cam into a vertical motion, and a vertical motion. A rocker arm that converts the vertical movement of the push rod into a rocking motion, an injection seat portion having a seat surface that is in close contact with the rocker arm tip surface, a unit injector that injects fuel through the injection seat portion, and the like. A lubricating structure for a unit injector drive device, comprising: an oil hole at least inside the rocker arm, wherein the oil hole is opened at a portion of the rocker arm tip surface in close contact with the seat surface. Surface and the seat surface Forming a groove as a groove, the groove has one end communicates with the oil hole, the other end and wherein the opening to the outside of the close portion.

According to a second aspect of the present invention, in the first aspect, the position where the other end of the concave groove opens outward is a position where the oil flows in a direction toward the inside of the space where the rocker arm and the like are installed.
In a third aspect based on the first or second aspect, the direction in which the concave groove is formed is parallel to the sliding direction between the rocker arm tip surface and the seat surface. In a fourth aspect based on the first to third aspects, an oil reservoir recess is formed in the cylinder head near the push rod hole through which the push rod passes, and the oil reservoir recess communicates with the push rod hole. Form a push rod oil hole. The fifth invention is
In the fourth invention, oil dripped from at least one rocker arm of an intake valve driving rocker arm and an exhaust valve driving rocker arm installed in the space,
A passage is formed on the upper surface of the cylinder head so as to flow into the oil reservoir recess. The lubrication structure of the unit injector drive device according to the present invention has the above-described configuration.

[0011]

The operation of the present invention having the above configuration will be described. One of the features of the present invention is that a close contact portion between the rocker arm tip surface and the seat surface of the injection seat portion communicates with an oil hole opened at the rocker arm tip surface, and opens into a space formed by a cylinder head and a cylinder head cover. The provision of the concave groove serving as an oil groove enables good lubrication between the tip surface of the rocker arm and the seat surface, and also improves the ability to release air mixed into the oil hole of the rocker arm. Further, since the opening position outside the concave groove is a position where the oil flows in the inner direction of the space, the oil scattered from the opening does not directly collide with the cylinder head cover, so that noise generation due to the collision can be prevented. Further, since the direction in which the concave groove is formed is parallel to the sliding direction between the rocker arm tip surface and the sheet surface, the mating surface is not damaged during sliding.

Next, since oil flows from the oil reservoir concave portion to the push rod hole via the push rod oil hole, the amount of oil supplied to the cam follower portion, which becomes a high load, particularly the contact portion between the cam and the cam follower increases. And good lubrication is obtained. Further, since the oil dripping from the rocker arms for driving the intake valve and the exhaust valve flows into the push rod hole for the unit injector, the lubricating property is improved even when the contact portion between the cam and the cam follower has a higher load.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lubrication structure for a unit injector drive device according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a front view of a partial cross section of a lubrication structure of a unit injector drive device of the present invention as an example applied to an internal combustion engine, for example, a diesel engine. FIG. FIG. 2A shows a ZZ view of FIG. In FIG. 2, (a) shows when the unit injector is not injecting fuel, and (b) shows when the unit injector is injecting fuel.

A unit injector driving device 10 is mounted on a cam 1 that rotates in synchronization with engine rotation, a cylinder block 3, a cam follower 2 that converts the rotational motion of the cam 1 into a vertical motion, and a rocker arm 6 that converts the vertical motion of the cam follower 2 into a rocker arm 6. The push rod 5 is transmitted to the rocker arm, the rocker arm 6 swings up and down by the movement of the push rod 5, the injection seat portion 7 that is in close contact with the rocker arm 6, and a plunger that injects fuel by pressing the injection seat portion 7 downward. ), And the like. The injection sheet portion 7 includes an injection sheet 11 that forms a flat sheet surface 11a that is in close contact with the flat distal end surface 6a of the rocker arm 6, and has a spherical surface that can slide with the spherical portion of the substantially hemispherical injection sheet 11. It comprises a spring holder 12 and a spring 13 forming a recess.

Next, the unit injector driving device 10
With respect to the lubrication structure of the above, an oil hole 22 in the axial direction of the shaft 21 connected to an oil supply line (not shown) is formed inside the shaft 21 that allows the rocker arm 6 to rotate, and communicates with the oil hole 22. An oil hole 23 penetrating in a substantially diametric direction is formed. The rotatable portion 24 with which the rocker arm 6 opens at both ends of the oil hole 23 is provided with a gap in which oil film-like oil can be supplied. Oil holes 25 and 26 are drilled in the rocker arm 6, one end of which is open to the rotatable portion 24, and the other end is a surface near the end 6 b on the push rod 5 side of the rocker arm 6, and a portion of the injection sheet 11. It is open at the close contact with the seat surface 11a. A concave groove 27 serving as an oil groove is formed on the flat distal end surface 6a of the rocker arm 6, and one end communicates with the oil hole 26, and the other end has
Outside the close contact portion, inside the space formed by the cylinder head 4 and the cylinder head cover 9 ,
It is open at the position where the oil flows in the interior direction of the space .
The direction in which the concave groove 27 is formed depends on the rocker arm 6.
Of the front end face 6a of the
It is substantially parallel to the sliding direction 29 with the contact surface 11a. further,
An oil passage 31 is formed on the upper surface of the cylinder head 4, an oil recess 32, and a push rod oil hole 34 communicating with the oil recess 32 and the push rod hole 33 are formed in the cylinder head 4 near the push rod hole 33. . Thus, oil dripping from the concave groove 27 or the like can be dripped into the push rod hole 33 through the passage 31, the oil reservoir concave portion 32, and the push rod oil hole.

At the time of operation of the engine having such a configuration, the oil is supplied to the portion closely contacting the seat surface 11a of the injection sheet 11 through the oil holes 22, 23, the rotatable portion 24, and the oil hole 26, and flows into the concave groove 27. While lubricating the close contact portion, it flows into the oil hole 28 penetrating the injection sheet 11 and enables good sliding between the spherical portion of the injection sheet 11 and the spherical concave portion of the spring holder 12. Further, the oil easily flows into the concave groove 27, and the air flowing into the oil hole 26 is easily released. further,
In the prior art, the oil holes 72 (FIG.
(See FIG. 5), a portion of the oil scatters in the direction of the arrow 62 (see FIG. 5) and collides with the cylinder head cover 9 to generate noise. However, since high oil pressure is prevented, oil is not scattered at high speed, which contributes to noise reduction. As described above, the groove 27 is provided on the inner side of the space, that is ,
Is open to the flow of position, the oil scattered from the opening
There is no direct collision with the cylinder head cover.
Noise generation due to collision can be prevented. Furthermore, the concave groove 27
More preferably, it is formed substantially parallel to the sliding direction 29 from FIG. 2 (a) to FIG. 2 (b). Thereby, it is possible to prevent the mating surface of the close contact portion from being damaged during sliding.

Next, the oil dripping from the concave groove 27 or the like drops into the push rod hole 33 through the push rod oil hole 34 as described above, flows as indicated by an arrow 41, and the spherical sliding between the push rod 5 and the cam follower 2 occurs. Lubricate the moving part 42,
The high load contact portion 44 between the cam follower 2 and the cam 1 is lubricated by dripping as indicated by an arrow 43. Further, the oil flowing out from the oil hole 25 to the surface near the end 6b of the rocker arm 6 is supplied to the end 6b of the rocker arm 6 in the same manner as described in the related art.
The lubrication is performed on a spherical contact portion 45 between the push rod 5 and the push rod 5, a spherical contact portion 42 between the push rod 5 and the cam follower 2, and a contact portion 44 between the cam follower 2 and the cam 1. This allows
In particular, a contact portion 4 between the cam follower 2 and the cam 1 which causes a high load.
4, a good lubrication state is ensured, and the reliability of the contact portion 44 is improved.
The durability is improved.

Although the lubrication structure of the unit injector drive device according to the present invention has been described in detail, the present invention is not limited to the embodiment. The concave groove 27 may be provided on a portion other than the flat distal end surface 6a of the rocker arm 6, and may be formed on the sheet surface 11a of the injection sheet 11. The cross-sectional shape of the concave groove 27 may be any shape that can be formed, such as a V-shape or a U-shape. Further, an oil passage is formed on the surface of the cylinder head 4 at a position where the oil drops from the rocker arms for driving the intake valve and the exhaust valve installed inside the space, and one end of the oil reservoir recess 3 near the push rod oil hole 34 is formed.
2 and may lubricate the contact portion 44 and the like. Instead of this oil passage, unit injector, intake valve,
A weir may be provided around the upper part of the push rod hole for driving the exhaust valve.

[0019]

Since the present invention is configured as described above, it has the following effects. An oil groove is formed at the close part between the flat surfaces of the rocker arm tips, so even when the engine is running at low speed and the oil pressure is low, the air in the oil hole escapes and sufficient oil is supplied to the close part to ensure good lubrication. Is always possible, and the reliability and durability of the engine are improved. Further, even when the engine is rapidly accelerated and the rise of the oil pressure is delayed, the air bleeding property is improved, so that quick lubrication and lubrication to the close contact portion is possible. Also,
Good air bleeding of oil hole prevents high pressure oil in oil hole
Noise is reduced without oil splattering from close parts at high speed
With a greatly contributing oil groove is placed rocker arm, etc.
It opens at the position where the oil flows in the interior direction of the space where
The oil scattered from the opening does not directly collide with the cylinder head cover, so that noise generation can be prevented. In addition, since it has an oil passage, oil sump recess, push rod oil hole, etc.,
The amount of oil supplied to the cam follower for driving the unit injector is increased, and good lubrication is particularly possible at the contact portion between the cam follower and the cam surface, which causes a high load, thereby improving the reliability and durability of the cam follower and the cam.

[Brief description of the drawings]

FIG. 1 is a front view of a partial cross section of a lubrication structure of a unit injector drive device according to the present invention.

FIG. 2 is a cross-sectional view of the vicinity of the tip of the rocker arm of FIG.

FIG. 3 is a ZZ view of FIG. 2 (a).

FIG. 4 is a front view of a partial cross section of a lubrication structure of a unit injector driving device according to the related art.

5 is a cross-sectional view of the vicinity of the tip of the rocker arm in FIG. 4;

FIG. 6 is a cross-sectional view of a lubricating structure of a unit injector driving device according to another related art near the tip of a rocker arm.

[Explanation of symbols]

1 cam, 2 cam follower, 3 cylinder block,
5 push rod, 6 rocker arm, 8 unit injector, 11 injection seat, 12
Spring holder, 23, 25, 26, 28 Oil hole, 2
7 Concave groove, 31 passage, 32 oil reservoir recess, 33 push rod hole, 34 push rod oil hole, 44 high load contact part.

Claims (5)

(57) [Claims] 1. A cam, a cam follower for converting the rotational motion of the cam into a vertical motion, a push rod for transmitting the vertical motion, a rocker arm for converting the vertical motion of the push rod into a oscillating motion, and a seat surface closely contacting the tip surface of the rocker arm. A unit injector driving device including an injection sheet portion provided, a unit injector for injecting fuel through the injection sheet portion, and the like, comprising at least an oil hole inside the rocker arm, wherein the oil hole is formed at the rocker arm tip surface. In a lubricating structure of a unit injector driving device that opens at a close contact portion with a seat surface, a concave groove serving as an oil groove is formed at a close contact portion between the rocker arm tip surface and the seat surface, and one end of the concave groove has the oil hole. And the other end is open to the outside of the close contact portion. Lubrication structure of the unit injector drive. 2. The lubricating structure of a unit injector drive device according to claim 1, wherein the position where the other end of the concave groove is opened outward is a position where oil flows in a direction inside a space where the rocker arm and the like are installed. 3. The lubricating structure of a unit injector drive device according to claim 1, wherein a direction in which the concave groove is formed is parallel to a sliding direction between the rocker arm tip surface and the seat surface. 4. An oil reservoir concave portion is formed in a cylinder head near a push rod hole through which the push rod passes, and a push rod oil hole communicating the oil reservoir concave portion with the push rod hole is formed. 1 to 3
The lubricating structure of the unit injector drive device according to the above section. 5. An oil dripping from at least one of a rocker arm for driving an intake valve and a rocker arm for driving an exhaust valve, which is installed inside the space, is formed on an upper surface of a cylinder head so as to flow into the oil reservoir recess. The lubricating structure for a unit injector drive device according to claim 4, further comprising a passage formed.