JPS6052283B2 - Engine valve clearance automatic adjustment method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic engine valve clearance adjustment method and apparatus.

Conventionally, when adjusting valve clearance on an engine assembly line, it is usually done manually.

This is done by a worker pushing a feeler gauge between the adjustment screw and the valve stem while rotating the camshaft.
Generally, the adjustment screw is tightened, and the operator judges the degree of tightening based on intuition when removing the gap gauge, and adjusts the clearance accordingly. For this reason, even though valve clearance requires high precision because it affects engine performance,
Because it relies on the operator's manual intuition, the adjustment accuracy tends to vary, and problems occur that require a lot of work time and skill.

Moreover, it is extremely difficult to automatically adjust valve clearance while rotating the camshaft. Therefore, the present applicant automatically adjusts the valve clearance with the camshaft stationary based on the fact that adjusting the valve clearance with the camshaft stationary corresponds to adjustment made while the camshaft is rotating. I tried my best. That is, the cam follower of the rocker arm is kept in contact with the base surface of the cam, the once tightened adjusting screw is loosened, and the displacement of the adjusting screw is determined from the state where the valve is seated on the valve seat. The purpose is to use this position change to set the valve clearance. However, in this case, the adjustment screw may be affected by the tension between the adjustment screw, the lock nut, and the threaded part of the rocker arm, or the error in the engagement part between the driver bit that operates the adjustment screw and the adjustment screw. This appears as a fluctuation error in axial displacement, and even a small error makes it impossible to accurately set the valve clearance, which has a large effect on engine performance. In addition, distortion of the rocker arm (which greatly affects valve clearance) requires many adjustment steps to remove this distortion, which tends to complicate automatic valve clearance adjustment.The present invention addresses this point. In view of this, we have developed an automatic engine valve clearance system that detects the displacement of the adjuster screw as a displacement in the direction away from the cam base surface of the cam follower of the rocker arm, and sets the valve clearance by replacing it with the clearance between the cam follower and the cam base surface. The present invention provides an adjustment method and an apparatus for the adjustment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Figures 1 and 2 show an embodiment of the valve clear run automatic adjustment device of the present invention, in which 1 is a machine frame in which a drive unit, which will be described later, is arranged, and a sub-assembly engine is mounted on the lower side of the machine frame 1. A jig 2 for setting the cylinder head 41 is provided. Reference numeral 5 denotes a mount frame that is guided by a guide bar 3 of the machine frame 1 and is moved up and down by an actuator, for example, a cylinder mechanism 4, arranged on the machine frame 1. A drive unit 6 is disposed on the mount frame 5. be.

4a is a rod of the cylinder mechanism 4.

The lowering limit of the drive unit 6 and, therefore, the lowering limit of the gantry frame 5 is regulated by the operation of a limit switch 7.
Reference numeral 10 denotes a rotating shaft that is rotatably and vertically movably supported via a bush 11 on a socket rotating shaft 19, which will be described later.The rotating shaft 10 is coaxial with the valve stem 43 of the cylinder head 41 set in the jig 2 It is arranged so that it is on top.

The upper end of this rotating shaft 10 is a drive unit casing 12.
It is fitted into the connection hole 14a of the output shaft 14 of the deceleration mechanism 13 disposed within the upper end, is connected to be slidable in the vertical direction by engagement of the key 15 and the key groove 16, and is fixed to the upper end of the casing 12. drive device, e.g. pulse motor 1
7, it is rotated in the forward and reverse directions via the deceleration mechanism 13. A driver bit 18 is removably fitted to the lower end of this rotating shaft 10 to engage with the upper end slit of an adjusting screw 47 for adjusting valve clearance screwed onto the tip of the rocker arm 45. Reference numeral 19 denotes a cylindrical socket rotating shaft that is fitted onto the rotating shaft 10, and the socket rotating shaft 19 is a cylindrical socket rotating shaft that is assembled to the casing 12 so as to be slidable in the vertical direction by engaging the key 21 and the keyway 22. a drive device supported by the holder 20 and fixed to the casing 12;
For example, the gear transmission mechanism 24 (consisting of a gear 24a fixed to the output shaft 23a of the DC motor 23 and a gear 24b fixed to the socket rotating shaft 19) is driven by the motor 23.

) for forward rotation. 25 is fixed to the lower end of the socket rotating shaft 19 by a bolt 26 so as to surround the driver bit 18 at the end of the rotating shaft 10, and is fitted into the lock nut 46 of the adjuster screw 47, and its lower end is connected to the rocker arm 45. This is a socket that comes into contact with the lock nut seating surface.

Further, the drive unit 6 itself is configured such that the upper side of its casing 12 is connected to the stand frame 5 by a ball joint mechanism 27 so that it can swing freely, and the axis of the valve stem 43 and the axes of the rotation shaft 10 and the socket rotation shaft 19 are aligned. Even if there is some misalignment, this misalignment can be absorbed and the socket 25,
The driver bit 18 is designed to be able to properly engage with the corresponding lock nut 46 and the sliding portion of the adjusting screw 47, and the casing 12 is provided between the lower side of the casing 12 and the pedestal frame 1. A centripetal mechanism 28 having a plurality of balance springs 29 which elastically support the outside of 12 in the radial direction is arranged to make the above-mentioned engagement more accurate. Furthermore, a plurality of leaf springs 30 are provided between the casing 12 and the pedestal frame 5 in the ball joint mechanism 27 portion, so that the swinging motion of the drive unit 6 is not hindered. It is designed to suppress rotation. 31 is a detector placed on the jig 2 side and is moved up and down by a cylinder mechanism 32 to measure the axial displacement of the valve; 33 is a mount frame 5;
cam follower 4 of the rocker arm 45.
The detector 33 measures the displacement in the direction away from the cam base 49a surface of 8, and the detector 33 comes into contact with the back surface of the cam follower on the normal line passing through the contact point between the cam follower 48 and the cam base 49a surface at the lowering limit of the gantry frame 5. .

The detection results of these detectors 31 and 33 are counted by counter registers 34 and 35. Reference numeral 36 denotes a control device that controls the operation of the cylinder mechanisms 4, 32, pulse motor 17, and motor 23;
1 and 33, and sends a predetermined operating signal to the pulse motor 17 and DC motor 23, or a signal to reset the counter registers 34 and 35 to ROJ.

In FIG. 1, 37 is a set spring for the rotating shaft 10, 38 is a set spring for the socket rotating shaft 19, and the total spring force of these set springs 37 and 38 is the valve 4
It is set weaker than the set spring 44 force of 2,
The driver bit 18 is inserted in the lowering area of the mount frame 5.
, press the adjusting screw 47 and the free end of the rocker arm 45 toward the valve stem 43 via the socket 25.

39 is a bearing member, and 40 is a lowering limit stopper for the rotating shaft 10.

Next, the manner in which the valve clearance is automatically adjusted by the embodiment apparatus having the above configuration will be explained with reference to the flowchart shown in FIG.

First, the cylinder head 41 is properly set on the jig 2 and clamped.

Then, when a start button on a control panel (not shown) is turned on, a signal is sent from the control device 36 to the cylinder mechanisms 4 and 32, and the drive unit 6 starts lowering, and the detector 31 moves to a predetermined position. Then, the counter register 34 is reset to ROJ. Simultaneously with this lowering of the drive unit 6, the pulse motor 17 operates in normal rotation at a low speed. When the drive unit 6 reaches the lower limit, the socket 2
5 holds the lock nut 46, the driver bit 18 engages with the upper end sliding part of the adjusting screw 47, and screws in the adjusting screw 47, and the tip of the detector 33 hits the back of the cam follower 48. come into contact with When the drive unit 6 reaches a predetermined lowering limit position, the lowering movement of the cylinder mechanism 4 is stopped by the operation of the limit switch 7. Here, when the socket 25 and the lock nut 46 are engaged, the axis of the valve stem 43 and the socket rotation axis 19
Even if the axes of the socket 25 and the
can be properly fitted into the lock nut 46.

On the other hand, when the cylinder head 41 is in a sub-assembled state, the valve clearance varies, and if there is a clearance between the end of the valve stem 43 and the end of the adjusting screw 47, or if there is clearance between the end of the adjusting screw 47,
7 may be tightened and the valve 42 may be slightly open.

If the former valve clearance occurs, the rotating shaft 1
In order to press the free end side of the rocker arm 45 toward the valve stem 43 side by the force of the set spring 37 of 0 and the set spring 38 of the socket rotation shaft 19L, the force of the cam follower 48 and the base surface 49a of the young arm 49 press the free end side of the rocker arm 45 toward the valve stem 43 side. Although the adjustment screw 47 is screwed in by the rotation of the driver bit 18, the valve 42 begins to open against the force of the set spring 44, and the reaction force of the valve set spring 44 acts on the rocker arm 45, thereby opening the cam follower 48. is the cam base surface 4
Close to 9a. In the latter case, the reaction force of the valve set spring 44 is already acting on the rocker arm 45, and the force of the cam follower 48 is pressed against the base surface 49a, and the adjuster screw 47 is screwed in by the rotation of the driver bit 10. Valve 42 will be opened further. By screwing in the adjustment screw 47, when the counter register 34 counts the set value Rmyo, the forward rotation of the pulse motor 17 is stopped, and
The counter register 35 is reset to RO, and the valve 4
2 completely open state is created. This counter register 3
After the ROJ reset in step 5, a signal is sent to the pulse motor 17 again, the pulse motor 17 is operated in reverse at a low speed, and the adjusting screw 47 is relaxed. The valve 42 is seated due to the loosening of the adjustment screw 47, but
The reverse rotation of the pulse motor 17 is continued. As a result, when the valve 42 is seated, the reaction force of the valve set spring 44 on the rocker arm 45 is released, and the free end of the rocker arm 45 is
Although the cam follower 48 and the cam base surface 49a are in contact with each other,
Therefore, the counter register 35 remains uncounted. When the adjusting screw 47 is further loosened from the time when the valve 42 is seated, the rocker arm. Since the free end side of the cam follower 45 is pressed toward the valve stem 43 side by the set springs 37 and 38 as described above, the cam follower 4
8 is displaced away from the cam base surface 49a, and this displaced position is detected by the detector 3'3 and the counter register 35! will be counted. When the counter register 35 counts a predetermined value RQJ, the loosening operation of the adjusting screw 47 due to the low speed reverse operation of the pulse motor 17 is stopped, and the predetermined valve clearance is set as the clearance between the cam follower 48 and the cam base surface 49a. Replaced and set. Note that the predetermined value RQJ
This replaces the gap between the adjuster screw 47 and the valve stem 43, that is, the valve clearance. When the predetermined valve clearance RQJ is formed in this way, the motor 23 is rotated in the normal direction until a specified torque, for example 3 kg.ml, is achieved.
9. The lock nut 46 is fastened through the socket 25 to ensure the valve clearance.

This valve clearance is displayed on a display device (not shown) by a signal from the control device 36. In addition, by controlling the rotation of the rotary shaft 10 with the pulse motor 717 as described above, there is an advantage that the torque retention property at the time of stopping is good and that the adjustment accuracy can be improved because immediate stopping can be performed.

As described above, according to the present invention, the adjustment work time can be significantly shortened by completely automating engine valve clearance adjustment, and the valve clearance can be adjusted by pressing the free end of the rocker arm toward the valve stem. Since the clearance is replaced with the clearance between the cam follower and the cam base surface of have an effect.

In addition, as mentioned above, the free end of the rocker arm is pressed toward the valve stem side, and the cam follower part of the rocker arm that comes into contact with the cam detects the displacement in the direction away from the base surface. Valve clearance can be adjusted with high accuracy without any influence of deflection deformation on the free end side of the rocker arm.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory diagram showing one embodiment of the device of the present invention, and FIG.
The figure is an enlarged view showing the mode of valve clearance adjustment, and FIG. 3 is a flowchart of the same embodiment. 1...Machine frame, 2...Jig, 5...
... gantry frame, 6 ... drive unit, 10
... Rotating shaft, 12 ... Casing, 17.
...Pulse motor, 18...Driver bit, 19...Socket rotating shaft, 23...
X motor, 25... Socket, 27... Ball joint mechanism, 28... Centripetal mechanism, 31...
... Valve axial direction displacement detector, 33 ... Cam follower separation direction displacement detector, 34, 35 ... Counter register, 36 ... Control device, 41 ...
・・Cylinder head, 421I01 valve, 431II
1 Valve stem, 44... Valve set spring, 45... Rocker arm, 46... Lock nut, 47... Adjustment screw, 48...
...Cam follower, 49...Cam, 49a.
...Cam base surface.

Claims (1)

[Claims] 1. A step of pressing the free end of the rocker arm toward the valve stem and holding the lock nut of the adjusting screw, and operating the adjusting screw in the tightening direction.
The process involves completely opening the valve, operating the adjusting screw in the loosening direction, detecting the displacement of the cam follower away from the cam base surface with the cam follower part of the rocker arm, and adjusting the valve clearance between the cam follower and the cam base surface. The process of replacing and setting with clearance,
A method for automatically adjusting engine valve clearance, which consists of the process of tightening a lock nut. 2. A machine frame equipped with a jig for fixing the cylinder head of the engine, a drive unit mounted to the machine frame so as to be movable up and down via a stand frame, and a valve axial displacement detection device disposed on the jig. and a cam follower separation direction displacement detection device that is disposed on the mount frame facing the back surface of the cam follower of the rocker arm and abuts against the back surface of the cam follower at the lowering limit of the mount frame to detect displacement of the cam follower in the direction away from the cam base surface. and a control device that has an arithmetic circuit that calculates the detected values of each of the detectors and controls the operation of the drive unit. A rotating shaft that is equipped with a matching driver bit and rotated forward and backward by a drive device, and a socket that fits into the lock nut of the adjusting screw at the lower end and presses the lock nut seating surface of the rocker arm, and is coaxial with the rotating shaft. An engine valve clearance automatic adjustment device comprising a socket rotating shaft rotatably fitted on the outside and rotated forward and backward by a drive device. 3. The drive unit has an upper part of the casing connected to the pedestal frame via a ball joint mechanism so as to be able to swing freely, and a portion of the casing between the outer periphery of the lower part of the casing and the pedestal frame. 3. The automatic valve clearance adjustment device for an engine according to claim 2, further comprising a centripetal mechanism having a plurality of balance springs that elastically support the outer side in the radial direction. 4. The engine according to claim 3, wherein a plurality of leaf springs are attached to the connection portion between the upper side of the casing of the drive unit and the pedestal frame, spanning the upper side of the casing and the pedestal frame. Valve clearance automatic adjustment device. 5. The automatic valve clearance adjustment device for an engine according to any one of claims 2 to 4, wherein the rotating shaft drive device is a pulse motor.