JPS6029801B2 - 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.

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

This is done by an operator inserting a feeler gauge between the adjustment screw and the valve stem while turning 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 manual intuition of the operator, the adjustment accuracy tends to vary, and there are other problems such as requiring a lot of work time and skill.

Therefore, in order to automatically adjust the valve clearance,
The methods disclosed in Japanese Patent Application Publication No. 52-50411 and Japanese Patent Application Publication No. 53-46512 were proposed. However, this also has a practical problem when considering the mechanism at the time of opening the valve, which will be described later. Therefore, the applicant proposes to automatically adjust 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. (Japanese Unexamined Patent Publication No. 55-37546)
(see issue). First, the applicant conducted a number of experiments to automatically adjust the valve clearance of an engine and discovered the following. In other words, the locking arm is considerably distorted by the action of the valve set spring when the valve is opened, and this distortion varies considerably between individual locking arms, and the amount of distortion is about 1M sound, which is the tolerance for valve clearance. That's true. Therefore, in order to automatically adjust the valve clearance, loosen the adjust screw that has been tightened once, find the axial displacement of the adjust screw from when the valve is seated on the valve seat, and use this amount of displacement to adjust the valve clearance. When setting, it is necessary to take the above-mentioned phenomenon into consideration.

The present invention has been devised in view of the above, and includes an automatic valve clearance adjustment method and method that detects the relative displacement between the adjust screw and the rocker arm as the axial displacement of the adjust screw and uses this displacement to set the valve clearance. The present invention provides such equipment. Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 4 show an embodiment of the automatic valve clearance adjustment device of the present invention. Reference numeral 1 denotes a machine frame in which a drive unit, which will be described later, is disposed, and a support unit is provided on the underside of the machine frame 1. A jig 2 for setting the cylinder head 50 of the assembled engine is provided. Reference numeral 5 denotes a gantry frame which is guided by a guide bar 3 of the machine frame 1 and moved up and down by an actuator, for example, a cylinder mechanism 4, which is connected to the machine frame 1. A drive unit 6 is disposed on the gantry frame 5.

4a is a rod of the shilling mechanism 4.

A cylinder head 50 is provided on the lower side of the pedestal frame 5 when the drive unit 6 is moved down together with the pedestal frame 5.
A presser 7 is attached to press and hold the cam follower 52 of the rocker arm 51 on the base surface (perfect circular surface) of the cam 53 of the camshaft. This pressure contact 7 is elastically loaded with a spring 9 at the tip of an arm 8 provided on the lower side of the pedestal frame 5, and is connected to a guide pin 10 and a guide rod. The forward and backward movements are guided by the bolt 11, and the cam follower 52 of the rocker arm 51 is brought into pressure contact with the cam 53 by the force of the spring 9 near the lowering limit of the drive unit 6. The lower limit of this drive unit 6,
Therefore, the lower limit of the gantry frame 5 is set by the limit switch 12.
It is regulated by the operation of. Reference numeral 13 denotes a rotary shaft that is rotatably and vertically movably supported via a bush 14 on a socket rotary shaft 22, which will be described later.The rotary shaft 13 is coaxial with the valve stem 57 of the cylinder head 50 set in the jig 2. It is arranged so that it is on top.

The upper end of this rotating shaft 13 is connected to the drive unit casing 15.
It is inserted into the connection hole 17a of the output shaft 17 of the deceleration mechanism 16 disposed in the upper end, and is connected to the upper end of the casing 15 so as to be slidable in the vertical direction by engagement of the key 18 and the keyway 19. Fixed drive, e.g. pulse motor 2
It is rotated forward and backward from the river via a speed reduction mechanism 16. A driver bit 21 is removably attached to the lower end of this rotary shaft 13 and engages with the upper end of the adjusting screw 54 screwed onto the tip of the rocker arm 51 for adjusting the valve clearance. Reference numeral 22 denotes a cylindrical socket rotating shaft extending outboard of the rotating shaft 13, and the socket rotating shaft 22 is a cylindrical socket rotating shaft roughly attached to the casing 15 so as to be slidable vertically by engagement with a key 24 and a keyway 25. A gear transmission mechanism 27 (gear 27a fixed to the output shaft 26a of the DC motor 26, gear 27b fixed to the socket rotating shaft 22) is supported by the holder 23 and is driven by a drive device installed in the casing 15, for example, a DC motor 26. It becomes more.

) for forward and reverse rotation. 28 is socket rotation axis 2
2, and a driver bit 21 at the end of the rotating shaft 13.
It is a socket that is fixed with a bolt 29 surrounding the adjustment screw 54 and competes with the lock nut 55 of the adjustment screw 54.

Here, since there is a burr in the breakage of the adjustment screw 54 mentioned above, the connection reference plane between the driver bit 21 and the adjustment screw 54 is the beveled end surface 21a of the driver bit 21, and the upper end surface 54 of the adjustment screw 54.
It is set as a. Further, the drive unit 6 itself has the upper side of its casing 15 connected to the stand frame 5 through a ball joint mechanism 30' so that it can swing freely, and the ball line of the valve stem 57, the rotation axis 13, and the socket rotation axis 2.
Even if there is a slight deviation between the marking lines of No. 2 and 2, this deviation is absorbed so that the socket 28 and driver bit 21 can properly engage with the corresponding slots of the lock nut 55 and adjustment screw 54. , the casing 15
The casing 15 is located between the lower end of the frame 1 and the mount frame 1.
A centripetal mechanism 31 having a plurality of springs 32 which elastically support the outer side in the radial direction is arranged to make the above-mentioned engagement more accurate. Furthermore, a plurality of leaf springs 33 are installed between the casing 15 and the pedestal frame 5 in the ball joint mechanism 30 portion, so that the swinging motion of the drive unit 6 is not hindered. Rotation of the unit 6 is suppressed. 3
4 is a detector 36 disposed on the jig 2 side and moved up and down by the cylinder mechanism 35 to measure the displacement of the valve 56 in the chick direction;
is attached to a holder 37 rotatably attached to the socket rotating shaft 22 of the drive unit 6, and the driver bit 21,
A detector that measures the axial displacement of the adjust screw 54 in all directions, specifically, the relative displacement amount between the adjust screw 54 and the lock nut 55, via the rotary shaft 13 and the actuator 38 rotatably attached to the rotary shaft 13. The detection results of these detectors 34 and 36 are sent to counter registers 39 and 40.
It is counted by

The aforementioned detector holder 37 and the actuator 38 are iron-fitted in the slot 15a formed on the side of the casing 15, and the actuator 3
8 and the detector 36 are arranged so that their corresponding positions do not deviate. Since the lock nut 55 is in complete contact with the rocker arm 51, the relative displacement may be detected between the adjustment screw 54 and the rocker arm 51. 41 is a control device that controls the operation of the cylinder mechanisms 4, 35, the pulse motor 20, and the DC motor 26. The control device 41 calculates the detected values of the respective detectors 39, 40, It includes an arithmetic circuit that sends a predetermined activation signal to the motor 26 or a signal that resets the counter registers 39 and 40 to "0".

In FIG. 1, 42 is a set spring for the rotating shaft 13, 43 is a set spring for the socket 28, 44 is a bearing member, 4
5 is a lower limit stopper for the rotating shaft 13, and 58 is a set spring for the valve 56.

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, after properly setting and clamping the cylinder head 50 on the jig 2, when a start button on a control panel (not shown) is turned on, a signal is sent from the control device 41 to the cylinder mechanisms 4 and 35. When the drive unit 6 starts lowering, the detector 34 moves to a predetermined position and waits.

Counter registers 39 and 40 are then reset to "0". At the same time as this drive unit 6 is lowered, the DC motor 2
6 is operated in reverse for a predetermined period of time, and D
The C motor 26 is operated in reverse at a low speed so as to rotate in the direction of loosening the lock nut 55, and as the unit 6 is lowered, the socket 28 engages with the lock nut 55, and the lock nut 55 is loosened once. The reason for performing this operation is to align the temporary tightening of the lock nut, which will be described later, to certain conditions and to stabilize the accuracy of valve clearance adjustment. Here, when the socket 28 and the lock nut 55 are engaged, even if the axis of the valve stem 57 and the pivot line of the socket rotating shaft 22 are slightly deviated, the oscillating motion of the drive unit 6 and the centering motion of the centripetal mechanism 31 are prevented. The core action allows the socket 28 to compete properly with the lock nut 55. Drive unit 6
reaches the predetermined lowering limit position, the mitt switch 12
The downward movement of the cylinder mechanism 4 is stopped by this operation.

In this lowered position, the pressure element 7 presses and fixes the cam follower 52 of the rocker arm 51 on the base surface of the cam 53, and moves the end of the rocker arm 51 on the side of the adjuster screw 54 in the direction away from the end of the valve stem 57. move it to

On the other hand, when the aforementioned timer T has not timed out, the DC motor 26 continues to operate in reverse, and the lock nut 55 is loosened to a predetermined loosening amount. Timer T,
When the time is up, the timer T2 operates to operate the pulse motor 20 in the reverse direction and at a low speed for a predetermined period of time, the pulse motor 20 is operated at a low speed in the reverse direction in the direction of loosening the adjustment screw 54, and the driver bit 21 is operated at a low speed in the reverse direction in the direction of loosening the adjustment screw 54. The adjustment screw 54 is loosened by engaging the upper end slot.

At the same time, the DC motor 26 operates in normal rotation, and the lock nut 5
Temporarily tighten 5 to a predetermined torque, for example, 7k9. This normal rotation operation of the DC motor 26 is controlled by a signal from a torque detector, such as a strain gauge 46, provided on the DC motor 26, and is continued until a specified torque is obtained, and the pulse motor 20 also operates until the timer T2 times out. The adjustment screw 54 is loosened to a predetermined loosening amount. Note that if the adjustment screw and the lock nut screw are manufactured with high precision, the lock nut does not necessarily need to be temporarily tightened, and the lock nut may be held in a loose state so as not to rotate. In this way, temporarily tighten the lock nut 55 and adjust the adjustment screw 5.
By performing the loosening step 4 at the same time, both operations can be performed smoothly with low torque, and the influence of backlash between the lock nut 55 and the adjuster screw 54 is reduced, and the adjuster screw 46 in the next process is
This is to prepare for the tightening. When the above-mentioned temporary tightening of the lock nut 55 is completed and the timer T2 times up, the adjustment screw tightening position of the device is obtained, the cylinder head 50 and the automatic adjustment device are matched, and the first step is started. finish.

Upon completion of the matching, the counter register 39 of the valve-side detector 34 is reset to "0", and a timer T operates the pulse motor 20 in normal rotation and low speed for a predetermined period of time.
3 operates, and the adjustment screw 54 is inserted vertically.

This is a process for creating seating conditions for the valve 56. If the counter register 39 is in a state of "0" after the pulse motor 20 has operated in the normal direction for a predetermined period of time, that is, the valve 56 is properly seated, then the next step is to When the detector 34 detects the displacement of the valve 56 in the bag direction and the counter register 39 counts, that is, the valve 56 is opened, an operation is performed to create a seating condition for the valve 56. . This resets the counter register 39 to "0" again if it has counted. Here, the counter register 39 is the valve 56.
It is assumed that the displacement in the closing direction can also be counted as a "positive" value. At the same time as the counter register 39 is reset to "0", a timer T4 is activated to operate the pulse motor 20 in reverse at a low speed for a predetermined period of time, and the pulse motor 20 is operated in reverse for a predetermined period of time to loosen the adjustment screw 54.

Then, the count display on the counter register 39, that is, “
If it is not "0", the counter register 39 is reset to "0" again, and the pulse motor 20
is operated in reverse, and the above operation is repeated until the counter register 39 becomes "0". When the counter register 39 becomes "0", the counter register 3
9 to count the displacement of the valve 56 in the opening direction and reset it to "0", the timer T3 is operated again, the pulse motor 20 is operated in normal rotation at low speed for a predetermined period of time, and the seating state of the valve 56 is confirmed.

Note that, depending on the case, the process may proceed to the next step of normal rotation high-speed operation of the pulse motor without activating the timer T3 again. When the seated state of the valve 56 is obtained, the pulse motor 20 is then operated in high-speed forward rotation, and the adjustment screw 54 is tightened to move the valve stem 57 by a predetermined amount m.
in the opening direction of the valve 56. At this time, by tightening the adjustment screw 54, a reaction force is applied to the rocker arm 51 by the valve set spring 58.
When the rocker arm 51 is in the valve seated state shown in FIG. 2A, the valve stem 57 is moved by the predetermined amount m with the adjusting screw 54 side end being distorted upward by 6 minutes as shown in FIG. 2B. become. This valve stem 5
7, the pulse motor 20
A timer T5 operates to operate the reverse rotation at a low speed for a predetermined period of time.
The pulse motor 20 is reversely operated in the direction of loosening the adjustment screw 54 to eliminate backlash between the driver bit 21 and the shield part of the adjustment screw 54.
At the same time, driver bit 21 and adjustment screw 54
Accurately connect the reference surface with the reference surface in preparation for adjusting the setting clearance in the next process. That is, as shown in FIGS. 3 and 4, the reference surface of the driver bit 21 is the lower end 21a, and the reference surface of the adjustment screw 54 is the upper end surface 54a. However, even though it is a reference plane, its accuracy is not that high. In particular, the accuracy of the upper end surface of the adjustment screw 54 is not high.
In addition, there is play between the sliding part of the adjuster screw 54 and the engaging part of the driver bit 21.
If the direction of rotation changes, the adjustment screw 54 will not rotate by this amount of play, regardless of the rotation of the driver bit. This is affected when fine adjustments such as valve clearance are required. This driver bit 2
1 and the upper end sliding part of the adjusting screw 54 is completed, the count value n (a value slightly changed from the above m) of the counter register 39 of the valve side detector 34 is calculated by the calculation built in the control device 41. At the same time as being stored in the circuit, the count register 40 of the adjusting screw side detector 36 is reset to "0".

Here, the adjusting screw side detector 36
When the counter register 40 is reset to "0", the detector 36 is attached to the socket rotating shaft 22 of the drive unit 6 itself as described above, and detects the amount of relative axial displacement between the socket rotating shaft 22 and the rotating shaft 13. In other words, the axial displacement of the adjustment screw 54 from the seating surface of the lock nut 55 of the rocker arm 51 is detected. Therefore, when the adjustment screw 54 is loosened, the Only the axial displacement of the adjustment screw 54 can be measured without being affected by distortion or the like. When the count register 36 is reset to "0" as described above, the pulse motor 20 is then operated in low speed reverse rotation, the adjustment screw 54 is loosened, and the amount of displacement of the lock nut 55 from the seating surface changes. is counted by the counter register 40.

Therefore, this counter register 40 corresponds to the set clearance Q of the valve 56 and the count value n of the counter register 39.
A predetermined valve clearance Q is set between the end of the valve stem 57 and the lower end of the adjusting screw 54 by loosening the adjusting screw 54 until the sum of . This valve clearance Q is the apparent clearance Q actually formed between the lower end of the adjusting screw 54 and the end of the valve stem 57, as shown in FIG. 2A. is set as the sum of the amount of distortion 6 of the rocker arm 51. In other words, the apparent clearance Q that is actually formed as described above is narrower by the amount of distortion of the rocker arm 51 by 6 than the clearance Q obtained by the difference between the counter registers 39 and 40. Ru. When a predetermined valve clearance Q is formed in this way, the DC motor 26 is then rotated in the normal direction until a specified torque, for example 3 kg, is reached, and the lock nut 5
The final tightening in Step 5 is performed to ensure the valve clearance.

This valve clearance is then sent as a signal from the arithmetic circuit to a display device (not shown) as a difference between the detection values of the adjusting screw side detector 36 and the valve side detector 34, and is displayed on the display device. In addition, in the above, the valve 56
When detecting the seating state, the displacement amount of the valve side detector 34 in all directions is used for detection, but the seating state is detected by measuring the displacement speed of the valve side detector 34 in the hoe direction. In this case, the displacement speed becomes "0" in the seated state. In addition, a pulse motor 20 for driving the aforementioned rotating shaft 13 and a DC motor for driving the socket rotating shaft 22 are provided.
Although the motor 26 is not limited to this, in particular, by controlling the rotation of the rotating shaft 13 with the pulse motor 20, the torque retention property at the time of stopping is good, and since immediate stopping can be performed, adjustment accuracy can be improved. In addition, by controlling the rotation of the socket rotating shaft 22 with the DC motor 26, two states with a large difference in tightening torque, that is, the lock nut 55
It has the advantage of being able to accurately handle both temporary and final tightening.

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 clearance can be set to a value that takes into account rocker arm distortion, etc., and the adjustment screw The relative displacement of the rocker arm is detected as the axial displacement of the adjust screw in all directions, and the clearance is adjusted by adjusting the axial displacement of the adjust screw in all directions, so the pitch error of the screw does not appear as a clearance error, resulting in extremely high precision. The clearance can be adjusted, and its practical effects are great.

[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.
Figures A and B are enlarged views showing valve clearance adjustment modes;
FIG. 3 is an enlarged view showing the relationship between the driver bit and the adjustment screw, FIG. 4 is a sectional view taken along line AA in FIG. 3, and FIG. 5 is a flowchart of the same embodiment. 1...Machine frame, 2...Jig, 5...
... mount frame, 6... drive unit, 7.
... Pressure contact, 13 ... Rotating shaft, 20 ...
...Pulse motor, 21...Driver bit, 22...Socket rotating shaft, 26...
DC motor, 28...Socket, 30...
... Ball joint mechanism, 31 ... Centripetal mechanism, 33 ... Stopping mechanism, 34 ... Valve axial displacement detector, 36 ... Adjustment Screw axial displacement detector, 39, 40... Counter register, 41... Control device, 50...
...Cylinder head, 51...Rotsuka arm,
52... force muffler, 53... force, 54... adjustment screw, 55... lock nut, 56...
...Valve, 57...Valve stem. Figure 3 Figure 4 Figure 1 Figure 2 (A) Figure 2 (B) Figure 5

Claims (1)

[Claims] 1. A step of press-contacting and holding the cam follower of the locking arm against the base surface of the cam and holding the lock nut of the adjusting screw, and operating the adjusting screw to detect the axial displacement of the valve. a step of seating the valve on the valve seat, a step of operating the adjusting screw and displacing the valve appropriately in the axial direction to associate the adjusting screw with the valve, and a step of associating the adjusting screw with the valve. The process of setting a predetermined valve clearance based on the detected value of the axial displacement detector and the detected value of the axial displacement detector that detects the relative displacement between the adjuster screw and the locker arm, and the process of tightening the lock nut with a predetermined torque. An automatic engine valve clearance adjustment method consisting of a tightening process. 2. The automatic valve clearance adjustment method for an engine according to claim 1, wherein the step of holding the lock nut of the adjustment screw is a step of temporarily tightening the lock nut. 3. The automatic valve clearance adjustment method for an engine according to claim 2, wherein the temporary tightening step is performed at the same time as the adjustment screw loosening operation. 4 The process of associating the adjustment screw and the valve is
The automatic valve clearance adjustment method for an engine according to any one of claims 1 to 3, comprising two steps of forward rotation and reverse rotation of an adjusting screw. 5 A machine frame equipped with a jig for fixing the cylinder head of the engine, a drive unit mounted on 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. an adjusting screw axial displacement detector disposed in the drive unit to detect relative displacement between the adjusting screw and the rocker arm; and an arithmetic circuit for calculating detection values of each of the detectors. The drive unit includes a pressure contact that presses the cam follower of the rocker arm against the base surface of the cam at its lower limit, and a pressure contact that engages the upper end of the adjusting screw at the lower end. A rotary shaft that is rotated forward and backward by the drive device and that transmits the axial displacement of the adjusting screw to its detector, and a rotating shaft that holds the adjusting screw axial displacement detector and has an adjusting screw at the lower end. The socket is provided with a socket that fits into the lock nut of the strike screw, and a socket rotating shaft that is externally fitted coaxially to the rotating shaft so as to be rotatable and slidable in the axial direction, and that is rotated in forward and reverse directions by a drive device. Engine valve clearance automatic adjustment device. 6. The drive unit has an upper part connected to the pedestal frame so as to be able to swing freely, and a centripetal mechanism equipped with a plurality of balance springs is attached between the outer periphery of the lower part and the pedestal frame. Claim No. 5 consisting of
Automatic valve clearance adjustment device for the engine described in Section 1. 7. The automatic valve clearance adjustment device for an engine according to claim 6, wherein a rotation prevention mechanism comprising a plurality of leaf springs is attached to the connecting portion between the upper side of the drive unit and the gantry frame. 8. The engine valve clearance automatic adjustment device according to any one of claims 5 to 7, wherein the rotating shaft drive device is a pulse motor. 9. The automatic valve clearance adjustment device for an engine according to any one of claims 5 to 8, wherein the drive device for the socket rotating shaft is a DC motor.