CN101438034A - Tappet clearance adjusting method and tappet clearance adjusting device - Google Patents

Abstract

The invention provides a tappet clearance adjusting method capable of setting clearance with high precision in a short time. The amount of protrusion of the valve (11) measured by the measuring means (10) is added to the target tappet clearance, and the value obtained by the addition is converted into the rotation angle of the adjustment screw. Specifically, when the target tappet clearance is 0.05mm and the amount of protrusion of the valve (11) measured by the measuring unit (10) is 0.1mm, the return angle (θ) of the adjusting screw (15) is as follows: θ ═ 0.05+0.1 ÷ 0.0013888 ═ 108 °. Here, 0.0013888(mm) is the screw feed amount when the adjustment screw (15) is rotated by 1 °.

Description

Tappet clearance adjustment method and tappet clearance adjustment device

technical field

The invention relates to a method for adjusting a tappet gap between a valve rod of an engine and an adjusting screw of a rocker arm and a device for adjusting the tappet gap.

Background technique

If the gap between the valve stem of the engine and the adjusting screw of the rocker arm (tappet gap) is too small, it will cause idling stability or engine stop, and excessive noise will be generated. Therefore, it is necessary to correctly adjust the tappet clearance in order to eliminate the above-mentioned disadvantages even during the cooling period and the heating period of the engine.

As a general tappet clearance adjustment method, it is known to insert a feeler gauge between the adjustment screw installed at the front end of the rocker arm and the valve stem, and feed the adjustment screw with a screwdriver until the feeler gauge is in a lightly crimped state. method, however, this method requires the operator to have skilled skills, and at the same time, because there is also the possibility of human error, therefore, the tappet clearance adjustment methods disclosed in Patent Documents 1 to 4 have been proposed.

In Patent Document 1, as an adjustment method without using a feeler gauge, a method is proposed in which the base end side of the rocker arm is pressed against the reference plane of the camshaft, and the adjustment screw on the other end side is screwed in by a screwdriver. Feed in, and then, when returning the adjusting screw to the displacement set value and adjusting the tappet clearance, set the amount fed through the above screwdriver to a point at which almost no displacement occurs even if the rocker arm is fed into the adjusting screw Therefore, it will not be affected by the play between the rocker arm and the rocker shaft or the play between the camshaft and its bearing.

Patent Document 2 discloses an adjustment method that does not use a feeler gauge. In a state where an air velocity sensor is inserted into the hole of the air supply cover, compressed air from an air source is supplied to the hole of the cylinder head, and then, Turn the adjusting screw to press the valve to the open side. Then, since the wind speed sensor can detect that the valve starts to open and the air flow toward the valve has been generated in the hole, when this time is regarded as the valve opening, the rotation position of the adjusting screw at this time is used as a reference, and the The screw is reversed by a specified amount to adjust the tappet clearance.

Patent Document 3 relates to an adjustment method using a feeler gauge. However, high-pressure air is supplied from an air source to the combustion chamber, and the threading amount of the adjustment screw is adjusted, and then the lock nut is tightened. When the tightening torque of the lock nut reaches When the specified value is reached, a timing signal is sent out to confirm whether the pressure in the combustion chamber at the moment the timing signal is output meets the range of the set value, thereby judging whether the tappet clearance is appropriate.

Patent Document 4 discloses a method of screwing in the adjustment screw until the displacement of the rocker arm reaches a stable region, and then loosening the adjustment screw based on the displacement detection device so that the displacement of the rocker arm becomes stable. The predetermined reference amount is decreased, and the adjustment screw is loosened by an amount obtained by subtracting the loosening amount corresponding to the reference amount of the rocker arm from the gap setting standard value with the loosened position as the adjustment origin.

Patent Document 1: JP-A-62-610.

Patent Document 2: JP-A-6-17619.

Patent Document 3: JP-A-11-153007.

Patent Document 4: Japanese Unexamined Patent Publication No. 2001-27106.

In the method described in Patent Document 1, the displacement rate of the rocker arm must be obtained each time, which has the problem of not only increasing the man-hours for adjustment, but also complicating the configuration of the device.

In the method described in Patent Document 2, although the valve opening time can be determined from the value detected by the wind speed sensor, it is difficult to accurately detect the valve opening time, and an air speed sensor must be inserted, resulting in poor workability.

In the method described in Patent Document 3, it is necessary to use a conventionally used feeler gauge, which increases the number of steps and time.

Although the method described in Patent Document 4 is improved compared to Patent Document 2, it is necessary to use a displacement detection device to measure the displacement of the rocker arm, which increases the time for adjustment.

Contents of the invention

In order to solve the above-mentioned problems, the tappet gap adjustment method of the present invention first detects the position of the surface of the seated valve surface portion with the measuring unit, and then rotates the adjustment screw by an adjustment unit equipped with a nut screwing mechanism or the like, thereby, Press the stem to protrude the valve by a predetermined amount, then measure the protrusion amount of the valve with the measuring unit, add the measured valve protrusion amount to the target tappet clearance, and convert the added value In order to adjust the rotation angle of the screw, the adjustment unit rotates the adjustment screw in the opposite direction at a changed angle and returns.

According to the present invention, it is possible to accurately adjust the tappet clearance in a short time without using a feeler gauge.

Description of drawings

Fig. 1 is an overall view of a tappet gap adjusting device of the present invention.

FIG. 2 is an enlarged view of an essential part of FIG. 1 .

Fig. 3 is a block diagram of the tappet gap adjustment method of the present invention.

Fig. 4 is a schematic view of the state before adjustment of the tappet gap adjustment method of the present invention.

Fig. 5 is a schematic diagram of the state during the adjustment process of the tappet gap adjustment method of the present invention.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is an overall view of a tappet gap adjusting device of the present invention. Fig. 2 is an enlarged view of the main part of Fig. 1 , with respect to the workbench 1 on which the workpiece (cylinder head of the engine) is placed, the swing arm 2 is freely swingable under the drive of the cylinder 3 through the axis in the horizontal direction, On the swing arm 2 is mounted an adjustment unit 4 assembled with a nut screwing mechanism. In addition, under the drive of the above-mentioned cylinder 3, the adjustment unit 4 can be selectively switched to any position of the valve on the exhaust side and the valve on the suction side of the workpiece.

As shown in FIG. 2 , a rail 5 is provided along the longitudinal direction of the swing arm 2 , and a plate 6 is engaged with the rail 5 , and the plate 6 is connected to an air cylinder 7 provided on the swing arm 2 .

Furthermore, the plate 6 and the adjustment unit 4 are moved forward and backward in the axial direction of the swing arm 2 by the expansion and contraction of the above-mentioned air cylinder 7 .

The above-mentioned plate 6 is provided with a rail 8 in a direction perpendicular to the above-mentioned rail 5, and this rail 8 is engaged with one end of the adjustment unit 4, and one end of the adjustment unit 4 is moved along the rail 8 by means of a cylinder 9. In addition, The middle portion of the adjustment unit 4 is held between the guides 2 a provided on the above-mentioned swing arm 2 . In this way, one end of the adjustment unit 4 is moved by the cylinder 9, thereby biasing the adjustment unit 4 in the axial direction, which can be adapted to a model change or a workpiece with multiple valves.

In addition, a measurement unit 10 constituting a tappet gap adjustment device together with the adjustment unit 4 is fixed to the workbench 1 corresponding to the respective positions of the exhaust side valve and the suction side valve.

Based on FIGS. 3 to 5 , an adjustment method using the tappet gap adjusting device configured as above will be described.

First, the valve 11 is seated on the valve seat 12 . This process is accomplished by means of a spring 14 mounted in compression between the end of the valve stem 13 and the workpiece.

Then, the surface position of the surface portion of the valve 11 in the seated state is detected by the measuring unit 10 . This state is shown in FIG. 4 . In addition, in this state, although a gap is formed between the end of the valve rod 13 and the adjustment screw 15, this gap is not an accurately set gap.

Next, after the lock nut 16 is temporarily fixed by the adjustment unit 4 , the lock nut 16 is loosened. Here, the reason why the lock nut 16 is temporarily fixed is because there may be a situation where it is not possible to detect that the lock nut has come off when the lock nut 16 is only loosened.

Next, in a state where the lock nut 16 is loosened, the adjusting screw 15 is screwed in by the adjusting unit 4 by rotating the adjusting screw 15 (screwed in to the opening side). Afterwards, after screwing in the adjusting screw 15, return slightly in order to eliminate the wobbling that occurs when returning. This is necessary to improve measurement accuracy.

In the above operation, the valve 11 protrudes to the open side. The protrusion amount is measured by the measuring unit 10 described above. Here, the adjusting screw 15, the valve 11 and the measuring element are connected in series. As for the amount of protrusion of the valve 11 , it protrudes until it reaches a stable region where rattling between the rocker arm and the shaft disappears.

Thereafter, the protrusion amount of the valve 11 measured by the measuring unit 10 is added to the target tappet gap, and the added value is converted into the rotation angle of the adjusting screw.

In the following, a numerical example will be specifically described. In the case where the target tappet gap is 0.05 mm, and the protrusion amount of the valve 11 measured by the measuring unit 10 is 0.1 mm, the return angle (θ) of the adjusting screw 15 is:

θ=(0.05+0.1)÷0.0013888=108°.

Here, 0.0013888 (mm) is the screw feed amount when the adjustment screw 15 is rotated by 1°.

After turning the adjustment screw 15 to adjust the lifter clearance to a set size as described above, the lock nut 16 is tightened to move the adjustment unit 4 and the measurement unit 10 backward, and the adjustment operation of the lifter clearance is completed.

Claims (4)

1. a tappet clearance adjusting method is characterized in that, comprising:

Detect the operation of position of face of the valve face part of the state of taking a seat with determination unit;

By regulation unit rotation adjusting screw, be pressed into valve rod and make valve with the outstanding operation of established amount;

Measure the operation of the overhang of described valve by described determination unit;

The overhang of the valve that described determination unit is measured and tappet clearance addition as target, the value transform that this addition is obtained is the operation of the angle of swing of adjusting screw;

By described regulation unit, adjusting screw is rotated and the operation returned round about with the angle of described conversion.

2. tappet clearance according to claim 1 adjusting method is characterized in that,

Described regulation unit comprises nutting mechanism.

3. tappet clearance regulating device, it is used to implement the described tappet clearance of claim 1 adjusting method, it is characterized in that,

In order to carry out suction side and exhaust side adjustment separately with a regulation unit, described regulation unit is installed on the swing arm.

4. tappet clearance according to claim 3 regulating device is characterized in that,

Described determination unit is arranged on suction side and the exhaust side position separately.

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