JP2830715B2 - Valve clearance adjustment device for engine valve train - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve clearance adjusting device for setting and inspecting a valve clearance of a valve train of an engine.

[0002]

2. Description of the Related Art A valve train of an engine used in an automobile or the like is provided with an intake / exhaust valve provided on a cylinder head, a camshaft for driving the intake / exhaust valve, and the like. For example, in the valve train provided in the cylinder head 1 of the engine shown in FIG.
And the exhaust valve 2b are opened and closed by cams 6a and 6b via rocker arms 4a and 4b. Cams 6a, 6b
Is provided on the camshaft 8. Valves 2a, 2b
Are urged in the valve closing direction by the resilience of the valve spring 10, and each of the valves 2a and 2b is brought into contact with the valve seat 12 by the shank portion 11 when the valve is closed.
The protrusion amounts for a and 4b are regulated. Each valve 2
a and 2b are a stem (valve shaft) 13 and a retainer 1 respectively.
4 is provided.

An adjusting screw 16 for adjusting the valve clearance is provided between the upper end of the stem 13 of each of the valves 2a and 2b and the rocker arms 4a and 4b. 4b is transmitted to the valves 2a and 2b. The adjusting screw 16 is fixed by a lock nut 17. In FIG. 11, a cylinder block 18 is provided below the cylinder head 1, and a piston 19 is accommodated in the cylinder block 18.

In the above valve operating system, the intake and exhaust valves 2a,
In order to open and close the valve 2b with a predetermined lift amount, the valve clearance needs to be within a predetermined numerical range, and the clearance adjustment by the adjusting screw 16 requires high accuracy. Conventionally, such adjustment of the valve clearance is manually performed by an operator using a jig such as a gauge on an engine assembly line.

[0005]

The conventional valve clearance adjustment work requires a lot of trouble and time, and the measurement of the clearance requires not only the skill of the worker but also the variation of the measurement due to the individual difference of the worker. May occur. Therefore, it has been desired to develop a device that can efficiently and accurately adjust the valve clearance in an engine assembly line. Note that JP-A-Hei 3
-206306 JP
Means for detecting the amount of valve lift, and adjusting
Turn the screw and the camshaft
Is described. However, this conventional
The technology uses a micrometer on the underside of the bulb
The valve lift is detected by contacting the
The cylinder head and cylinder block
The actual clearance in the actual machine condition cannot be measured.
No. In other words, appropriate valve clear with the cylinder head alone
Even if a lance is obtained, move the cylinder head to the cylinder
When tightened to the block, the
Lube clearance may be improper. Also
In this conventional technique, when the camshaft makes one rotation,
The camshaft rotation speed is used to detect the total lift of the camshaft.
If the stylus moves too fast, such as when
The balance may not be measured correctly. For this reason
The rotation speed of the motor shaft cannot be increased, clearing
The cycle time of the lance adjustment work becomes slow.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a clearance adjusting apparatus capable of efficiently and accurately adjusting a valve clearance and simultaneously performing a clearance inspection.

[0007]

SUMMARY OF THE INVENTION The present invention, which has been developed to achieve the above object, comprises an intake / exhaust valve, a camshaft for driving these valves, and an adjusting screw for adjusting valve clearance. An apparatus for adjusting a valve clearance of a cylinder head, comprising a probe that is brought into contact with an end face of a retainer provided on the valve, and detecting a displacement amount of the valve in an axial direction; An adjustment bit having a tip end that can be fitted to the adjustment screw and an adjustment screw rotation mechanism having a forward / reverse rotation actuator for rotating the adjustment bit by a predetermined amount; and a lock nut screwed to the adjustment screw. Has a matable socket and an actuator for rotating the socket And a lock nut tightening mechanism, the drive source and a cam shaft for rotating said cam shaft
A camshaft rotation mechanism having rotation angle detection means for detecting a rotation angle of the camshaft;
When rotating the shaft, the rotation angle detection means
Calculating means for inputting the detected rotation angle of the camshaft and obtaining the actual valve clearance based on the valve lift detected by the displacement sensor.

[0008]

The cylinder head is fixed at a predetermined position, and the adjusting screw rotating mechanism, the lock nut tightening mechanism and the displacement sensor are located above the valve. Then, the probe of the displacement sensor is brought into contact with the end face of the retainer of the valve. Further, the tip of the adjustment bit is fitted to the adjustment screw. In this state, the adjustment bit is rotated by the adjustment screw rotating mechanism, and the adjustment screw is rotated in a direction to make the clearance zero.
Since the clearance is zero at the moment when the adjusting screw contacts the valve (the moment when the valve is moved), the rotation of the adjustment bit is stopped when the displacement sensor detects even a slight movement of the valve. By doing this. Zero adjustment of the clearance is performed.

When the clearance is zero, the camshaft rotating mechanism rotates the camshaft once, and the displacement sensor detects the amount of displacement of the valve, thereby measuring the valve lift at the time of zero clearance.

Next, a clearance is set between the valve and the adjusting screw by reversing the adjustment bit by the adjusting screw rotating mechanism.
In this case, by determining the pitch of the adjusting screw in advance, the number of rotations of the adjusting screw required to obtain a predetermined clearance is calculated, and the adjustment bit is rotated in reverse by the number of rotations. After that, the lock nut is tightened by the lock nut tightening mechanism to fix the adjustment screw.

After the clearance is set as described above, the camshaft is rotated once again, and the displacement sensor detects the amount of displacement of the valve.
Measure the valve lift amount after setting the clearance. Then, an actual clearance is obtained based on the difference between the valve lift amount when the clearance is zero and the valve lift amount after the clearance is set, and it is determined whether or not the clearance is within a reference range.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. The clearance adjusting device 20 shown in FIG. 2 includes a work supporting device 22 at a lower portion thereof.
The work support device 22 is for holding an assembly of the cylinder head 1 as a work and the cylinder block 18 at a predetermined position. This work is carried into a predetermined position by a transfer mechanism such as a transfer machine.

A crankshaft 24 is housed in the cylinder block 18. In the case of this embodiment, the cylinder block 18 is carried in a state where the rotation angle of the crankshaft 24 is regulated such that the piston of each cylinder is located at the top dead center or the bottom dead center. The cylinder head 1 has intake and exhaust valves 2a and 2b, rocker arms 4a and 4b, a camshaft 8, a valve spring 10 as in the valve train shown in FIG.
And so on.

As shown in FIGS. 1 and 2, the clearance adjusting device 20 has a base 26. A crankshaft rotation mechanism 28 is provided on the base 26. The crankshaft rotation mechanism 28 includes a joint 29 having a shape that can be fitted to the end 24a of the crankshaft 24. The drive source 30 can rotate the crankshaft 24 to a desired angle (for example, 90 °). And can be rotated in the opposite direction by a desired angle (for example, -90 °).

A cam shaft rotating mechanism 32 is provided on the base 26. This camshaft rotation mechanism 3
2 includes a joint portion 33 having a shape that can be fitted to the end 8 a of the camshaft 8, a drive source 34 and a rotation angle detecting means such as a rotary encoder, and the like. The rotation angle can be detected. The detected rotation angle of the camshaft 8 is input to an arithmetic processing unit 60 described later.

An upper structure 40 is provided on the base 26. As shown in FIG. 1, the upper structure 40 is provided with an adjustment / inspection head 41 for an intake valve located on the right side in the figure and an adjustment / inspection head 42 for an exhaust valve located on the left side. These adjustment / inspection heads 41 and 42 can be moved up and down along guide rails 44 and 45, and can be driven up and down by a predetermined stroke by lifting actuators 46 and 47 such as fluid pressure cylinders.

The basic structures of the adjustment / inspection head 41 on the intake side and the adjustment / inspection head 42 on the exhaust side are common to each other. As shown in FIG. 2 as a representative example of the exhaust-side adjustment / inspection head 42, this embodiment apparatus 20 is capable of simultaneously adjusting two valves (in total, four valves) for each of the intake side and the exhaust side. For this purpose, two sets of adjustment / inspection heads 42 are provided on each of the intake side and the exhaust side. These adjustment / inspection heads 42 can be sequentially moved onto the valves of each cylinder by a horizontal feed mechanism (not shown) such as a ball screw and a servomotor provided on the upper structure 40. ing.

A rocker arm retainer 50 is provided below the upper structure 40. This rocker arm presser 50
A rocker arm 4a,
4b can be pressed from above.

As shown in FIG. 1, each of the adjustment / inspection heads 41 and 42 has a displacement sensor 55.
An example of the displacement sensor 55 is a magnescale, and includes a sensor body 56 and a probe 5 extending below the sensor body 56.
7. The probe 57 faces the upper end surface of the retainer 14 as an example of a member on the valve side, and when the adjustment / inspection heads 41 and 42 drop to a predetermined position, the tip end of the probe 57 contacts the upper end surface of the retainer 14. It is supposed to. When the probe 57 is displaced in the axial direction with respect to the sensor main body 56, an electric signal corresponding to the amount of displacement is transmitted to the arithmetic processing unit 60. The arithmetic processing unit 60 uses a microcomputer or the like.

The displacement sensor 55 has a horizontal support shaft 61.
, And is fixed so that the inclination angle of the axis of each displacement sensor 55 matches the inclination angle of the valves 2a and 2b. Therefore, when the direction in which the valves 2a and 2b are lifted and the direction in which the probe 57 moves match,
Even if the valves 2a and 2b are lifted, the contact position of the probe 57 does not change, and the contact can always be reliably made at one point.

The above adjustment / inspection heads 41 and 42 include:
As shown in FIG. 3 representatively of one head 41, an adjusting screw rotating mechanism 70 and a lock nut tightening mechanism 71 are provided. The adjusting screw rotating mechanism 70 is provided with an actuator 7 provided on the base member 72.
5 and an adjustment bit 76 rotated by the actuator 75. The tip of the adjustment bit 76 has a shape (for example, a shape like the tip of a Phillips screwdriver) that can be fitted to the adjustment screw 16. An example of the actuator 75 is an AC servomotor, and N
By the C control, the adjustment bit 76 can be rotated forward and backward by a desired number of rotations.

More specifically, the adjusting screw rotating mechanism 70 includes a driving shaft 79 connected to an output shaft of an actuator 75 via a coupling 78,
A bearing 80 rotatably supporting the drive shaft 79, an intermediate cylinder 81 connected to the lower end of the drive shaft 79, a movable shaft 82 held movably in the axial direction with respect to the intermediate cylinder 81, It is provided with push springs 85 and 86 for urging the shaft 82 downward, an adjustment bit 76 attached to the lower end of the movable shaft 82, and the like.

Therefore, the adjustment bit 76 can be moved vertically relative to the drive shaft 79, and the rotational force of the drive shaft 79 is transmitted to the adjustment bit 76 via the intermediate cylinder 81 and the movable shaft 82. The adjustment screw 16 is located on an extension of the adjustment bit 76.

On the other hand, the lock nut tightening mechanism 71 meshes with an actuator 90 such as an AC servomotor attached to the base member 72, a drive gear 91 provided on an output shaft of the actuator 90, and a drive gear 91. A driven gear 92, a bearing 94 that rotatably supports a shaft 93 of the driven gear 92, a rotating cylinder 95 that rotates integrally with the driven gear 92, and is held movably in the axial direction with respect to the rotating cylinder 95. Cylindrical socket 96 and socket 96
And a pressing spring 97 for urging the rotating cylinder 95 downward. The inner surface of the lower end of the socket 96 is formed in a shape that can be fitted to the lock nut 17.

Therefore, the socket 96 is vertically movable relative to the rotary cylinder 95, and the rotational force of the actuator 90 is transmitted to the socket 96 via the driving gear 91, the driven gear 92, and the rotary cylinder 95. become.

Next, the clearance adjusting device 2 having the above configuration
The operation of 0 will be described with reference to the flowcharts of FIGS. In step S1, an assembly of the cylinder head 1 and the cylinder block 18 as a work is carried into the clearance adjustment device 20 and held at a predetermined position. In the work to be carried in, since the piston of each cylinder is located at the top dead center or the bottom dead center, step S2 is performed to lower the piston at the top dead center to some extent.
, The crankshaft 24 is rotated 90 ° by the crankshaft rotation mechanism 28. In step S3, the camshaft 8
Is rotated by 360 °, the movable parts such as the camshaft 8 and the valves 2a and 2b are adapted.

In step S4, it is determined whether or not the clearance adjustment of all valves has been completed. Until the clearance adjustment of all valves is completed, the clearance adjustment step S5 shown in FIG. A clearance setting and a clearance inspection are performed for each valve. Since the intake valve 2a and the exhaust valve 2b perform substantially the same clearance adjustment operation, the intake valve 2a will be described below.

First, in step S10, after the adjustment / inspection head 41 is positioned on a desired valve 2a,
In step S11, the adjustment / inspection head 41 and the rocker arm presser 50 are lowered. Then, as shown in FIG. 6, the tip of the probe 57 of the displacement sensor 55 is connected to the valve 2.
a and the adjusting bit 7
6 is fitted to the adjusting screw 16 and the socket 96 is fitted to the lock nut 17. Further, the rocker arm 4a is pressed by the rocker arm presser 50. Note that the lock nut 17 is loosened in advance. Also,
Preferably provided in advance appropriate clearance C ₀ between the valve 2a and the adjustment screw 16.

In step S12, the adjusting screw 76 is rotated clockwise by the adjusting screw rotating mechanism 70, whereby the adjusting screw 16 is advanced in the direction of zero clearance. in this case,
As shown in FIG.
Since the clearance becomes zero at the moment of contact with the end face a, the rotation of the adjustment bit 76 is stopped when the displacement sensor 55 detects that the valve 2a has slightly moved. By doing so, zero adjustment of the clearance is performed.

Next, the rocker arm presser 50 is raised in step S13 to make the rocker arm 4a rotatable. Then, in step S14, the camshaft 8 is rotated by the camshaft rotating mechanism 32 to 360 degrees.
By rotating the valve 2 at the same time, the displacement amount of the valve 2a is detected by the displacement sensor 55 and input to the arithmetic processing unit 60, whereby the valve lift amount at zero clearance is measured. After that, the rocker arm presser 50 is lowered again in step S15.

Next, in step S16, the adjustment bit 76 is rotated counterclockwise by a predetermined number of revolutions by the adjusting screw rotating mechanism 70, whereby
The adjustment screw 16 is screwed in a direction away from the valve 2a, setting a predetermined clearance C ₁ as shown in FIG. The setting of the clearance C ₁ is obtained by obtaining the pitch of the adjusting screw 16 in advance.
Previously calculated rotational speed necessary to obtain a predetermined clearance C ₁ from the time of clearance zero (rotation angle), sets the desired clearance C ₁ and this by the rotation angle amount by rotating the adjustment bit 76.

After setting the above clearance C ₁ ,
In step S17, the lock nut 17 is tightened by rotating the socket 96 by the lock nut tightening mechanism 71 as shown in FIG. The adjusting screw 16 is fixed by an adjusting bit 76. As a result, the adjusting screw 16 is
7 fix to the rocker arm 4a. after that,
In step S18, the rocker arm presser 50 is raised again.

Then, in step S19, the camshaft 8 is again rotated by the camshaft rotating mechanism 32 into 360.
While rotating the valve, the displacement amount of the valve 2a is detected by the displacement sensor 55 and input to the arithmetic processing unit 60 to measure the valve lift amount after the clearance is set.

As shown in FIG. 10, the valve lift amount L ₂ (step S19) after the clearance is set is smaller than the valve lift amount L ₁ (step S14) when the clearance is zero. Become smaller. Therefore, in this embodiment, in step S20,
Obtains the actual clearance based on the difference of the above L ₁ and L _2, it is judged whether the the clearance is within the reference range, and displays to the operator such as through the result display device.

When the clearance is within the reference range, it is determined that there is no abnormality (OK). On the other hand, when the clearance is outside the reference range, there is an abnormality (NG)
And take appropriate measures such as resetting the clearance. After the inspection, step S2
In step 1, the adjustment / inspection head 41 is raised.

In the case of the cylinder head 1 for a four-cylinder, 16-valve engine as in this embodiment, the above-described clearance adjustment step S5 is repeated four times for each cylinder, and when the clearance adjustment for all valves is completed, the step is repeated. S
In step 6, the crankshaft 24 is rotated by -90 ° to return it to the same piston position as when the work is carried in, and then the work is carried out in step S7.

[0037]

According to the present invention, the valve lift is measured.
The displacement sensor is located outside the cylinder head.
Since the movement of the end face of the
The clearance between the adjustment screw and the valve can be set in the actual machine with the head and cylinder block assembled, and it is also efficient and accurate to determine whether the actual clearance after setting the clearance is appropriate Ru can be done. Also, a camshaft rotation mechanism according to the present invention.
Is provided with a drive source and a rotation angle detecting means, and is provided with a camshaft.
The cam output by this rotation angle detection means when rotating
The signal about the shaft rotation angle and the bar output by the displacement sensor
Whether to input the lift lift signal to the calculation means
Of the camshaft rotation angle.
Measurement of camshaft
Measurement failure component due to probe jumping during rotation
Can be processed by arithmetic means.
Cycle time by increasing the camshaft rotation speed.
This has a great effect on improving work efficiency and reliability of inspection accuracy, such as shortening .

[Brief description of the drawings]

FIG. 1 is a front view showing a part of a clearance adjusting device according to an embodiment of the present invention.

FIG. 2 is a side view of the device shown in FIG.

FIG. 3 is a sectional view showing a part of an adjustment / inspection head of the apparatus shown in FIG. 1;

FIG. 4 is a flowchart showing an outline of a working process by the apparatus of FIG. 1;

FIG. 5 is a flowchart showing a clearance adjustment step in FIG. 4;

FIG. 6 is a side view showing, in partial cross section, a state before clearance adjustment by the apparatus of FIG. 1;

FIG. 7 is a side view showing, in a partial cross section, a state at the time of zero clearance adjustment by the apparatus of FIG. 1;

FIG. 8 is a side view showing a state in which a clearance is set by the apparatus of FIG. 1 in a partial cross section.

9 is a side view showing a state in which a lock nut is tightened by the device of FIG. 1 in a partial cross section.

FIG. 10 is a diagram showing a relationship between a camshaft rotation angle and a valve lift.

FIG. 11 is a sectional view of a part of a cylinder head and a cylinder block showing a valve train.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylinder head 2a, 2b ... Valve 8 ... Camshaft 16 ... Adjust screw 17 ... Lock nut 20 ... Clearance adjustment device 32 ... Camshaft rotation mechanism 41, 42 ... Adjustment / inspection head 50 ... Rocker arm press 55 ... Displacement sensor 57 ... Probe 60: Arithmetic processing unit (arithmetic means) 70: Adjust screw rotating mechanism 71: Lock nut tightening mechanism 75: Actuator 76: Adjustment bit 90: Actuator 96: Socket

Claims (1)

(57) [Claims] An apparatus for adjusting valve clearance of a cylinder head having an intake / exhaust valve, a cam shaft for driving these valves, and an adjusting screw for adjusting valve clearance, A displacement sensor having a probe that is brought into contact with an end face of a retainer provided on the valve and detecting an axial displacement of the valve; an adjustment bit having a tip end that can be fitted to the adjustment screw; and the adjustment bit An adjusting screw rotating mechanism having an actuator capable of rotating forward and backward for rotating the adjusting screw by a predetermined amount, a socket capable of being fitted to a lock nut screwed to the adjusting screw, and a lock nut tightening having an actuator rotating the socket. Mechanism for rotating the camshaft. Drive source and cam for
A camshaft rotation mechanism having rotation angle detection means for detecting a rotation angle of the shaft; and a camshaft rotated by the camshaft rotation mechanism.
Cam detected by the rotation angle detecting means when
And a calculating means for inputting a rotation angle of the shaft and obtaining an actual valve clearance based on a valve lift amount detected by the displacement sensor.