JPH0441201Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a lifter that converts the rotational motion of a cam attached to a camshaft into linear reciprocating motion in a valve train of an internal combustion engine. This invention relates to a roller lifter that includes a roller that rolls in contact with a roller.

[Conventional technology]

Conventionally, a roller lifter is provided with rotation prevention means to prevent it from rotating about its own longitudinal axis when it reciprocates within a lifter insertion hole formed in a cylinder block. Most of the conventional anti-rotation means have a structure in which a anti-rotation bolt provided on the cylinder block side is inserted into a corresponding bolt hole or groove provided on the roller lifter side (for example, Japanese Utility Model Application No. 56-136106, Japanese Utility Model No. 136-106) −66806 etc.).

[Problem that the invention attempts to solve]

However, the conventional anti-rotation means as described above has a problem in that the workability of assembling the roller lifter is poor. That is, it is very difficult to align the roller lifter when inserting the roller lifter into the roller lifter hole of the cylinder block and then screwing the locking bolt into the bolt hole of the roller lifter. The reason is that the bolt hole of the roller lifter inserted into the roller lifter hole can only be seen visually through the screw hole for bolt insertion in the cylinder block, and the bolt hole of the roller lifter is in front of the screw hole for bolt insertion in the height direction and rotation. Inserting the positioning bolt into the bolt hole while checking the directional position not only requires skill but also requires a considerable amount of assembly work time. Therefore, due to the difficulty of such assembly work, there is a large possibility of incorrect assembly, and there is also a risk of damage to the roller lifter.

In addition to the above, it is also possible to improve the ease of assembly by forming the bolt hole into a groove with an open upper end. That is, by making the bolt hole into such an open groove, the positioning bolt is projected into the roller lifter insertion hole in advance, and care must be taken only in the direction of rotation until the open groove of the roller lifter contacts the positioning bolt from below. Just insert the roller lifter while doing so. However, since the positioning bolt comes into contact with the bottom surface of the open groove each time the roller lifter moves up and down, a large force is applied to the bottom surface of the open groove, resulting in strength problems such as cracking from the bottom surface of the groove.

An object of the present invention is to provide a roller lifter that is easy to assemble and has sufficient strength in view of the prior art as described above.

[Means for solving problems]

In order to achieve the above object, according to the present invention, a detent protrusion and a positioning protrusion are made to protrude in order from the cam along the axial direction of the roller lifter into the lifter insertion hole, and the roller lifter is provided with a rotation stopper and a positioning protrusion. Elongated holes and positioning grooves open to the outside are formed to correspond to the stop protrusions and the positioning protrusions, respectively.
The elongated hole has at least a length corresponding to the reciprocating stroke of the roller lifter and a width approximately equal to the diameter of the detent protrusion, and the positioning protrusion is located at a position where it does not come into contact with the positioning groove during the reciprocating movement of the roller lifter. will be placed.

[Effect]

The positioning protrusion is used only when assembling the roller lifter. That is, first, only the positioning protrusion is attached to the roller lifter insertion hole, and the roller lifter is pushed into the insertion hole while adjusting the position in the rotational direction until the positioning groove contacts the positioning protrusion. At this time, the long hole of the roller lifter is in a position facing the hole for the anti-rotation protrusion formed in the cylinder block, so simply inserting the anti-rotation protrusion into this hole, the anti-rotation protrusion can be inserted into the elongated hole of the roller lifter. brought precisely within. When the assembly of the roller lifter is completed in this manner, the roller lifter reciprocates within the length of the elongated hole, but at this time the open groove of the roller lifter no longer contacts the positioning protrusion.

〔Example〕

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings, but first a conventional roller lifter mechanism will be briefly described with reference to FIGS. 5 and 6.

FIG. 5 shows an overhead valve (OHV) engine, where 1, 3, 5, and 7 indicate an intake valve (or exhaust valve), a rocker arm, a cylinder head, and a cylinder block, respectively. A cam 13 of a valve drive camshaft 11 is connected to a rocker arm via a roller lifter 15 and a push rod 21. The roller lifter 15 has a roller 17 at its lower end that rolls while contacting the cam 13, and its hollow cylindrical main body 16 moves vertically (generally in the longitudinal axis direction) inside a lifter insertion hole 31 formed in the cylinder block 7. It slides back and forth. Pushrod 21
The lower end is pressed against the bottom of the hollow bore of the roller lifter 15. In this manner, the rotation of the cam 13 is converted into a linear reciprocating motion of the roller lifter via the roller 17, which opens and closes the intake valve (or exhaust valve) 1 via the push rod 21 and rocker arm 3.

A threaded hole 23 for a locking bolt 25 is formed in the cylinder block 7, and the bolt 25 is screwed into the threaded hole 23. On the other hand, a long hole 29 is formed in one side of the roller lifter 15 in correspondence with the screw hole 23 .
The elongated hole 29 has a length corresponding to the reciprocating stroke of the roller lifter 16 (that is, the cam lift amount of the cam 13), and a width approximately equal to the outer diameter of the tip of the bolt 25. By inserting the tip of the bolt 25 into the elongated hole 29, the roller lifter 15 is prevented from rotating in the rotational direction.

In the prior art as described above, assembling the roller lifter was troublesome as described above. That is, when inserting the roller lifter 15 into the lifter insertion hole 31, push it in from below while paying attention to the rotation direction and height direction so that the long hole 29 is in front of the screw hole 23 of the cylinder block 7. long hole 2
9 can only be confirmed from the outside through the screw hole 23, so the amount of push-in of the roller lifter cannot be easily confirmed. Insert the roller lifter 15 into the lifter insertion hole 31
After inserting the bolt 25 into the screw hole 23 to the specified position, insert the bolt 25 into the screw hole 23 and insert the tip into the roller lifter 15.
The assembly is completed by inserting it into the elongated hole 29 of.

Apart from this, as shown in FIG.
It is also possible to make the elongated hole 29 of 5 into an elongated groove 29' with an open upper end, but in this case, as described above, the bolt 25 will come into contact with the bottom surface of the slotted hole 29' every time the roller lifter 15 reciprocates, and the There is a problem that cracks occur on the bottom part. This crack is slot 2
This is due to the lack of strength due to the fact that the upper end of 9' is not connected, that is, it is open.

In order to solve the above problems, the present invention separates the anti-rotation function and the positioning function during assembly. According to the first embodiment of the invention shown in FIGS. 1 to 3, the cylinder block has a locking bolt 25.
In addition to the screw hole 23 for the positioning bolt 40 (first screw hole), the screw hole 2 is located above the screw hole 41 for the positioning bolt 40 so that it is parallel to the longitudinal axis of the roller lifter 15.
3 and are arranged in a straight line. On the other hand, a positioning groove 35 corresponding to the second screw hole 41 is formed in the main body 16 of the roller lifter 15. The positioning groove 35 is in line with the elongated hole 29, and is formed at the upper end of the roller lifter as a groove whose upper end is open. The second screw hole 41 is formed at a height such that it does not come into contact with the bottom surface of the groove 35 even when the roller lifter 15 moves to the uppermost position after the assembly of the roller lifter 15 is completed. Further, as will be described later, the height position of the second screw hole 41 is determined when the groove 35 is brought into contact with the positioning bolt 40 screwed into the second screw hole 41 when the roller lifter 15 is assembled.
9 is located in front of the first screw hole 23.

When assembling the roller lifter 15, only the positioning bolt 40 is screwed into the second screw hole 41 in advance so that the tip thereof protrudes into the lifter insertion hole 31. The roller lifter 15 is inserted from below into the lifter insertion hole 31 with its rotational direction aligned so that the elongated hole 29 and the first screw hole 23 are aligned. This insertion can be performed until the upper end open groove 35 of the roller lifter 15 comes into contact with the positioning bolt 40, so there is no need to pay any attention to the insertion amount of the roller lifter 15. The roller lifter 15 is the positioning bolt 4
0, the long hole 29 of the roller lifter 15 is automatically positioned in front of the first screw hole 23 as described above, so the locking bolt 25 is inserted into the first screw hole 23.
If screwed in, the tip of the locking bolt 25 will definitely protrude into the elongated hole 29. Once the locking bolt 25 is attached, when the user releases the roller lifter 16, the roller lifter is lowered until, for example, the upper end of the elongated hole 29 comes into contact with the locking bolt 25, and at this time the positioning bolt 40 is completely separated from the groove 35 of the roller lifter 15. Moreover, even if the roller lifter 15 moves up and down during its operation, the groove 35 does not come into contact with the positioning bolt 40 as described above.

As described above, according to the present invention, the position of the roller lifter 15 in the height direction and rotational direction is determined simply by inserting it into the lifter insertion hole 31 of the cylinder block 7, and then the locking bolt 25 can be assembled easily and accurately. As a result, ease of assembly is improved and no damage occurs during assembly. Further, since the positioning bolt 40 is structured so as to contact the roller lifter 15 only during assembly and not during operation even when the cam is at its maximum lift, the upper portion 18 of the roller lifter 15 can be made thin and lightweight.

Fig. 4 shows an example in which the present invention is applied to an overhead camshaft (OHC) engine. Hole 4
1) is upside down compared to the case in FIG. 1, but the operation and effect are exactly the same as in the case in FIG. 1.

Note that the bolts 25 and 40 may be simple pins.

[Effect of idea]

As described above, according to the present invention, not only the ease of assembling the roller lifter is greatly improved, but also the portion 50 (Fig. 2) connected between the long hole for preventing rotation and the positioning groove. Because of this, the strength of the elongated hole portion is also ensured sufficiently.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of the main parts of the roller lifter according to the present invention, Fig. 2 is a side view of the roller lifter of Fig. 1, Fig. 3 is a diagram showing only the roller lifter of Fig. 1, and Fig. 4 is a diagram showing only the roller lifter of Fig. 1. FIG. 5 is a longitudinal sectional view showing a conventional roller lifter, and FIG. 6 is a side view showing another example of the conventional roller lifter. 7...Cylinder block, 11...Cam, 15
... Roller lifter, 17 ... Roller, 25 ... Stopping bolt, 29 ... Long hole, 31 ... Lifter insertion hole, 35 ... Groove, 40 ... Positioning bolt.

Claims (1)

[Scope of utility model registration request] The roller lifter has a roller in contact with a cam at the lower end, and reciprocates in a linear direction in a lifter insertion hole formed in a cylinder block according to the rotation of the cam, and the roller lifter has a roller in the lifter insertion hole along the axial direction of the roller lifter. A detent protrusion and a positioning protrusion are made to protrude in order from the side closer to the cam, and elongated holes and a positioning groove open to the outside are formed in the roller lifter, respectively, corresponding to the detent protrusion and the positioning protrusion. The elongated hole has at least a length corresponding to the reciprocating stroke of the roller lifter and a width approximately equal to the diameter of the detent protrusion, and the positioning protrusion is located at a position where it does not come into contact with the positioning groove during the reciprocating movement of the roller lifter. A roller lifter for an internal combustion engine, characterized in that: