JPH0617619A - Method for adjusting tappet clearance - Google Patents

Abstract

PURPOSE:To detect the valve opening timing of a valve with a high accuracy by supplying the compressed gas to an air intake/exhaust port of an engine, inserting and arranging a wind speed sensor to the port, and detecting the valve opening timing of the air intake/exhaust valve from the detected value of the wind speed sensor. CONSTITUTION:An adjust screw 4a is operated by a first driving source 11, and a lock nut 4b is operated by a second driving source 12 to adjust the tappet clearance. The rotation of the adjust screw 4a is detected, and the detected value is received by a controller 13 from an encoder 14. On the other hand, the compressed air from an air source 17 is supplied to an opening surface of the respective port for suction use and for exhaust use through an air supplying head 15, and the signal from the wind speed sensor 20 arranged on the air supplying head 15 is received by the controller 13. The valve opening timing of the valve 2 is detected by the change of this signal. Thus, the valve opening timing is detected with high accuracy, and the adjusting accuracy of the tappet clearance is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the tappet clearance of an engine.

[0002]

2. Description of the Related Art Conventionally, as a method of adjusting tappet clearance, according to Japanese Patent Laid-Open No. 63-266105, an adjusting screw provided in a valve operating mechanism is rotated and sucked while pressure gas is supplied to an intake and exhaust port of an engine. Press the exhaust valve to the open side, measure the pressure change in the port due to valve opening with the pressure sensor, measure the valve opening time, and use the turning position of the adjustment screw as the reference when opening the valve. It is known that the required amount of clearance is obtained by reversing the adjusting screw by a predetermined amount.

[0003]

In the above-mentioned conventional example, the valve opening time is detected based on the pressure change in the port. However, due to the influence of the volume in the port, there is a slight response delay in detecting the pressure change. Since it occurs, it is difficult to detect the valve opening time with high accuracy, and there is a limit in improving the adjustment accuracy of the tappet clearance. The present invention has been made in view of the above points, and an object thereof is to provide a method capable of detecting a valve opening time point with high accuracy and improving the adjustment accuracy of tappet clearance.

[0004]

[Means for Solving the Problems] In order to achieve the above object,
The present invention detects the valve opening time of the valve by pushing the intake / exhaust valve to the open side by the rotation of the adjusting screw provided in the valve operating mechanism of the engine, and uses the turning position of the adjusting screw at the valve opening time as a reference. In the method of adjusting the tappet clearance in which the adjusting screw is rotated in the reverse direction by a predetermined amount, the pressure gas is supplied to the intake and exhaust ports of the engine, and the wind speed sensor is inserted and arranged in the port, and the detected value of the wind speed sensor changes. From the above, the time when the valve is opened is detected.

[0005]

[Operation] When the valve starts to open due to the turning of the adjusting screw, the pressure gas in the port flows toward the valve, and this flow is directly detected by the wind speed sensor installed in the port.
Thus, the valve opening time can be detected with high accuracy from the change in the detection value of the wind speed sensor. Then, the tappet clearance amount can be accurately adjusted to a predetermined value by reversing the adjustment screw by a predetermined amount from the rotational position when the valve is opened.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The illustrated embodiment is a DOHC type engine in which each intake and exhaust valve 2 provided in a cylinder head 1 of an engine is opened and closed by a separate valve operating cam 3 through a rocker arm 4. The present invention is applied to the adjustment of the tappet clearance. Each rocker arm 4
Are supported by seating members 5 on the cylinder head 1 via adjusting screws 4a, respectively.
The tappet clearance is adjusted by rotating a with the lock nut 4b loosened.

In order to adjust the tappet clearance, an operating head 10 which is moved up and down by a cylinder (not shown) is provided above the engine setting place, and the operating head 10 has a first drive including a servomotor. Source 11 and a second drive source 12 composed of a nut runner, etc. are mounted, and while the first drive source 11 operates the adjusting screw 4a via the driver 11a, the second drive source 12 drives the socket 12a on the outer periphery of the driver 11a. The lock nut 4b is operated via the above. Both drive sources 11,
12 is a controller 13 including a microcomputer
The adjustment screw 4
In order to detect the rotation amount of a, the rotary encoder 14 is attached to the first drive source 11, and the signal from the encoder 14 is input to the controller 13.

An air supply head 15 is provided with a packing 16 on the opening surface of each of the intake and exhaust ports 6 of the cylinder head 1.
The air source 1 is attached to the air supply head 15 through the
7 is formed, and the chamber 18 is communicated with the port 6 through the orifice 19, and the air source 1
The compressed air from 7 was supplied to the port 6 via the air supply head 15. Further, the air supply head 15 is provided with a wind speed sensor 20 to be inserted into the port 6, and a signal from the sensor 20 is also input to the controller 13. In the present embodiment, the wind speed sensor 20 is composed of a Pitot tube having a spherical head 20a having a plurality of side pressure holes (not shown), but another anemometer such as a hot wire type may be used.

When adjusting the tappet clearance,
First, compressed air is supplied to the port 6, and in this state, the lock nut 4b is loosened by the second drive source 12, then the adjust screw 4a is rotated by the first drive source 11, and the tail end side of the rocker arm 4 is pulled up and the tip end is pulled up. The side is rocked downward, and the valve 2 is pressed downward to the open side. When the valve 2 starts to open, a flow of air toward the valve 2 is generated in the port 6, and this flow is immediately detected by the wind speed sensor 20 inserted in the port 6, and a signal input from the sensor 20 to the controller 13 is detected. The change detects the valve opening time of the valve 2. Then, the turning position of the adjusting screw 4a at the time of opening the valve is detected based on a signal from the rotary encoder 14, and the adjusting screw 4a is reversely rotated by a predetermined amount stored in the controller 13 in advance based on the turning position. To do. As a result, the tappet clearance is accurately adjusted to a predetermined clearance amount corresponding to the predetermined amount, and finally the lock nut 4b is tightened to finish the adjustment work.

By the way, in a multi-valve engine having a plurality of intake and exhaust valves in one cylinder, when it is necessary to individually adjust the tappet clearance of each valve, as shown in FIG. The air velocity sensor 20 is inserted into each of the plurality of branch passages 6a branching from the to the plurality of valves 2 so that the opening time of each valve 2 can be individually detected by each wind velocity sensor 20.

[0011]

As is apparent from the above description, according to the present invention, the flow of gas generated in the port due to the opening of the valve is directly detected by the wind speed sensor inserted in the port. The valve timing can be detected with high accuracy, and the tappet clearance adjustment accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a cutaway side view of an example of an apparatus used for carrying out the method of the present invention.

FIG. 2 is a plan view showing an arrangement of wind speed sensors in a multi-valve engine.

[Explanation of symbols]

 2 valve 4 lower arm 4a adjusting screw 6 port 10 operating head 12 controller 15 measuring head 17 air source 20 wind speed sensor

Front page continued (72) Inventor Kazuyuki Iwata 1-10 Shinshinayama, Sayama-shi, Saitama Prefecture Honda Engineering Co., Ltd.

Claims (1)

[Claims] 1. An intake / exhaust valve is pressed toward the open side by rotation of an adjust screw provided in a valve mechanism of an engine to detect a valve opening time point of the valve, and a turning position of the adjust screw at the valve open time point is detected. In the method of adjusting the tappet clearance by rotating the adjust screw by a predetermined amount based on the reference, while supplying the pressure gas to the intake and exhaust ports of the engine, the wind speed sensor is inserted and arranged in the port, and the detected value of the wind speed sensor A method for adjusting tappet clearance, characterized in that the opening point of the valve is detected from the change.