JPH039282B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an engine tappet equipped with a rocker arm having an adjusting screw facing a valve stem at one end and a slipper surface facing a valve operating cam at the other end. This invention relates to a tappet clearance confirmation device for confirming clearance.

(Prior art) Conventionally, when checking tappet clearance, a feeler gauge is inserted between the adjusting screw and the valve stem, and the operator senses the slight resistance when pulling it out to check the amount of clearance. I am trying to determine whether it is appropriate or not.

(Problem to be Solved by the Invention) By the way, the reason why the valve stem is pushed down against the bubble spring is due to the valve mechanism, such as the clearance of the shaft support of the rocker arm, after the adjustment screw contacts the valve stem. This is when the backlash is absorbed and the contact force of the adjusting screw against the valve stem increases to a value equivalent to the bubble spring load.In the end, the true value of tappet clearance is when the slipper surface contacts the valve cam. The sum of the clearance that occurs between the adjustment screw and the bubble stem when value.

However, with the method using a feeler gauge as in the above-mentioned conventional technology, it is difficult to measure the true value of the tappet clearance, including play in the valve mechanism, and it is difficult for the operator to insert or remove the feeler gauge. This is a type of sensory test that determines the suitability of tapepet clearance based on the degree of resistance felt by the user, requiring a high level of skill and poor workability.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus that can solve these problems and measure the true value of the tappet clearance accurately and with good workability.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a displacement detection means for detecting displacement of a predetermined detection portion on one end of the rocker arm, and a mounting portion for an adjustment screw on one end of the rocker arm. The valve stem is characterized by comprising a pulling means for pulling up in a direction away from the valve stem with a force corresponding to the valve spring load.

(Function) When the adjustment screw attachment part on one end of the locker arm is pulled up in the direction away from the valve stem by the pulling means from the state where the adjustment screw is in contact with the valve stem, the slipper surface first moves to the valve stem due to the rocking of the locker arm. The rocker arm comes into contact with the base circular portion of the cam, and then the backlash of the valve mechanism is absorbed by the lifting force from the lifting member, and the one end of the rocker arm is further pulled up by that amount.

Here, if the amount of displacement of the attachment part of the adjustment screw at the time when the slipper surface comes into contact with the base circular part is l ₁ and the subsequent displacement of the attachment part is l ₂ , then l ₁ is the amount of displacement of the attachment part of the adjustment screw at the time when the slipper surface comes into contact with the base circular part. Equal to the clearance created between the adjustment screw and the valve stem when they are in contact with the valve stem,
In addition, _l2 has the pulling force of the pulling means equal to the valve spring load, so that the backlash of the valve mechanism that is absorbed when a lifting force from the valve stem side equivalent to the valve spring load is applied to the adjustment screw is reduced. Therefore, if we calculate the amount of displacement l ₃ (l ₃ = l ₁ + l ₂ ) of the mounting part of the adjusting screw of the rocker arm from the deviation of the displacement value detected by the displacement detection means before and after pulling up, we can determine that this is the tappet. This is the true value of the clearance.

(Embodiment) Referring to FIG. 1, a shows a rocker arm that is mounted on a cylinder head of an engine, and one end of the rocker arm a has an adjusting screw _a1 facing a valve stem b, and a fixing nut _a2 thereof. At the same time as installing the
A slipper surface _a3 facing the valve drive cam c is formed at the other end, and the rotation of the valve drive cam c pushes down the valve stem b through the rocker arm a against the valve spring _b1 . A tappet clearance adjustment device that constitutes a valve train mechanism and is equipped with a confirmation device of the present invention disposed above the cylinder head allows adjustment of the tappet clearance and confirmation of the adjusted tappet clearance to be performed at the same stage. I made it.

The adjusting device includes a first movable frame 1 that is movable up and down in a direction substantially along the axial direction of the valve stem b, and a second movable frame 2 that is movable up and down in the vertical direction directly above the valve drive cam c. The first movable frame 1 is provided with an operating means 3 for adjusting the adjustment screw _A1 , and the second movable frame 2 is provided with a displacement detecting means 4 for detecting the displacement of a predetermined detection portion _A4 on one end side of the rocker arm A. the operating means 3 while detecting the displacement of the detection portion _a4 by the detecting means 4;
After tightening the adjusting screw _a1 , the locking arm a is pushed up by the amount of backlash in the valve mechanism due to the reaction force of the adjusting screw _a1 against the valve stem b, and then the valve stem b resists the valve spring _b1 . Determine the point in time when the detection part a4 is pressed down based on the change in displacement of the detection part _a4 ,
At this time, the position of the adjusting screw _A1 is set as the origin position for adjusting the tappet clearance, and the adjusting screw _A1 is loosened by a predetermined clearance amount from this position to adjust the tappet clearance. ing.

The operating means 3 includes a driver 3a driven by a servo motor (not shown) mounted on the upper part of the first movable frame 1, and a spline at the lower end of an output shaft 3b of a nut runner (not shown) on the first movable frame 1. The screwdriver 3 is configured with an engaged socket 3c.
a into the socket 3c through the output shaft 3b, and with the socket 3c engaged with the fixing nut _A2 and the driver 3a with the adjusting screw _A1 , first reverse the socket 3c. fixing nut
_A2 was loosened, then the screwdriver 3a was rotated to tighten and loosen the adjusting screw _a1 as described above, and finally the socket 3c was rotated in the normal direction to tighten the fixing nut _a2 .

The detection means 4 is composed of a sensor capable of detecting the movement of the measuring element 4a at the lower end on the order of microns, and is attached to a bracket 2a fixed to the second movable frame 2, and is attached to the lower end of the bracket 2a. A swinging arm 5 is provided around the shaft 5a as a fulcrum and is urged downward by a spring 5b, and a contact seat 5c is formed at the tip of the arm 5 to abut against the upper surface of one end of the rocker arm a. The measuring head 4a is placed on top.
The abutment part of the corresponding seat 5c against the rocker arm a is used as a detection part _a4 , and its displacement is detected by the detection means 4, and the cylinder 6a formed on the second movable frame 2 is used as a detection part a4. A pressing piece 6 is provided which is moved up and down via a piston rod 6b, and when adjusting the tappet clearance described above, the pressing piece 6 pushes down the other end of the rocker arm a, so that the slipper surface a ₃ of the valve cam c is It is kept in contact with the circular part of the base.

Further, the first movable frame 1 is provided with a pulling means 7 which can freely pull up the attachment part of the adjustment screw _a1 at one end of the rocker arm a in the direction away from the valve stem b. A tilting frame 8 that can be tilted laterally using a shaft 8a as a fulcrum is mounted on a bracket 1a at the lower end fixed to the first movable frame 1. At the bottom of the tilting frame 8, an adjustment screw _a1 is attached to the lower surface. A piston rod 10b extending downward from a lifting cylinder 10 formed at the top of the tilting frame 8 is connected to the upper end of the hook 9 by inserting the engageable hook 9 so as to be able to move up and down, and connecting the hook 9 to the cylinder 10. The valve spring _b1 can be pulled up with a force corresponding to the spring load of the valve spring b1, and the fixed frame 11 is attached to the bracket 1a at the side of the tilting frame 8, and the tilting frame 8 is attached to the fixed frame 11. A tilting cylinder 12 that moves up and down a wedge piece 12a that abuts the lower side surface.
According to the downward movement of the wedge piece 12a, the tilting frame 8 is tilted counterclockwise in the drawing against the spring 8b inserted between it and the fixed frame 11, and the hook 9 is engaged with the lower surface of the attachment of the adjusting screw _A1 as shown in the second figure, and in this state, by operating the lifting cylinder 10, the attachment portion is applied to the valve spring load via the hook 9. It was made to be able to be pulled up by force.

Next, to explain its operation, after adjusting the tappet clearance as described above, the pressing piece 6 is moved upward, and the one end side of the rocker arm a is pushed down by the biasing force of the spring 5b of the swing arm 5, and the adjusting screw a is is brought into contact with the valve stem b, and the detected value of the displacement detecting means 4 is reset to zero, and then the mounting part of the adjusting screw _a1 is pulled up with a force corresponding to the valve spring load by the pulling means 7 as described above, and the The detected value of the displacement of the detection part _a4 by the detection means 4 at the time is multiplied by the ratio of the distance between the adjustment screw _a1 and the detection part _a4 with respect to the pivot point of the rocker arm a.
Find the amount of displacement of rocker arm a at the attachment part of _a1 .

As explained in the operation section above, this amount of displacement is determined by the clearance l generated between the adjusting screw _a1 and the valve stem b when the slipper surface _a3 is brought into contact with the circular base portion of the valve drive cam c. ₁ and the backlash l ₂ of the valve mechanism that is absorbed when an upward force equivalent to the valve spring load is applied to the adjusting screw a ₁ , l ₃ , which is equal to the true value of the tappet clearance. Thus, it is possible to accurately determine whether or not the tappet clearance is appropriate based on this amount of displacement.

(Effects of the Invention) As described above, according to the present invention, it is possible to accurately measure the true value of the tappet clearance including the backlash of the valve mechanism, and it is possible to accurately measure the true value of the tappet clearance, including the backlash of the valve mechanism, and it is possible to accurately measure the true value of the tappet clearance, including the backlash of the valve mechanism, and it is possible to measure the true value of the tappet clearance including the backlash of the valve mechanism. This has the effect of improving work efficiency and making it easier to automate confirmation work.

[Brief explanation of drawings]

FIG. 1 is a cutaway side view of a tappet clearance adjusting device equipped with the device of the present invention, and FIG. 2 is a cutaway side view of the main parts during clearance confirmation operation. a...Lotsuka arm, a ₁ ...adjustment screw, a ₃ ...
Slipper surface, a ₄ ...detection part, b ... valve stem, b ₁ ... valve spring, c ... valve train cam,
4... Displacement detection means, 7... Pulling means.

Claims (1)

[Claims] 1 A device for checking the tappet clearance of an engine equipped with a rocker arm having an adjustment screw facing the valve stem at one end and a slipper surface facing the valve operating cam at the other end, which detects a specified detection value at one end of the rocker arm. A tapepet comprising: displacement detection means for detecting displacement of the part; and pulling means for pulling up the mounting part of the adjustment screw at one end of the rocker arm in a direction away from the valve stem with a force corresponding to the valve spring load. Clearance confirmation device.