JPH0818204B2 - Valve mounting method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a valve assembling method for mounting an intake / exhaust valve on an engine.

[Conventional technology]

During valve assembly work, in which the valve upper seat for supporting the valve spring and mounting the valve on the engine is mounted on the upper end of the valve stem via the split type valve cotter, the engagement protrusion of this valve cotter engages the cotter engagement of the valve stem. It may not fit properly in the groove and may cause an assembly error. Most of such assembling errors are not caused by defective parts, but are caused by misalignment at the time of assembling, incomplete valve cotter division, and the like.

For this reason, conventionally, the valve assembling operation is repeated twice uniformly to reduce the occurrence rate of assembling errors and prevent the productivity from being lowered due to the stop of the assembling line.

[Problems to be solved by the invention]

However, actually, in most valve cotters, the engaging protrusion fits into the cotter engaging groove of the valve stem in one assembling operation, and therefore the second operation is almost unnecessary. Therefore, the conventional valve assembling method has a problem that an unnecessary time cycle is required in the assembling process.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention has a valve cotter which has an annular engaging projection on the inner circumference, is formed in a tapered shape with the outer diameter increasing toward the upper side, and is divided parallel to the axial direction. Is pre-fitted into a tapered hole having the same gradient as the outer diameter of the valve cotter in the valve upper seat arranged above the valve spring, and the valve stem having an annular cotter engaging groove at the upper end is mounted on the valve upper seat. In the valve assembling method, the engaging protrusion of the valve cotter is fitted into the cotter engaging groove of the valve stem by the assembling operation of once inserting the taper hole from below and pulling it back again, and the valve upper seat is attached to the valve stem. During valve assembly operation, the operation of the valve cotter is detected and the valve stem does not rise to the specified position. When the normally occurs, the valve assembly repeats the operation again, when the operation abnormality of the valve cotter persists be repeated a suitable number of times, is characterized by capable of emitting an alarm stop operation.

[Work]

The valve assembling operation when the valve cotter operates normally will be described. The valve upper seat is pressed downward in advance against the urging force of the valve spring. When the valve stem is fitted into the taper hole of the valve upper seat, the upper end of the valve stem is caught by the engaging protrusion to lift the valve cotter. Then, the divided valve cotter moves its outer diameter upward by being guided by the taper hole of the valve upper seat and expands the inner diameter, so that the engagement protrusion is not caught on the upper end of the valve stem, and only the valve stem moves further upward. Move to. Then, when the cotter engaging groove of the valve stem rises above the engaging protrusion of the valve cotter, this valve stem is pulled back this time. Then, when the cotter engagement groove of the valve stem reaches the position of the engagement protrusion of the valve cotter again,
The valve cotter is pulled down together by hooking the engaging projection. Therefore, when the divided valve cotter fits into the tapered hole of the valve upper seat and is fitted again, the engaging projection of the valve cotter fits into the cotter engaging groove, and the downward pullback of the valve stem is restricted. . In this state, when the valve upper seat is released from the pressure and is urged upward by the valve spring, the valve cotter with the engaging projection fitted in the cotter engaging groove of the valve stem has an outer diameter in the tapered hole of the valve upper seat. Since it can be tightened, the valve upper seat can be securely attached to this valve stem. Since the positional relationship between the valve upper seat and the valve stem is relative, for example, the valve upper seat may be pulled up instead of pulling back the valve stem.

Examples of abnormal operation of the valve cotter include, for example, when the upper end of the valve stem catches the engaging projection and lifts the valve cotter, the valve cotter does not split and moves upward while being caught on the upper end of the valve stem, or the valve stem moves upward. When fitted into the taper hole of the seat in a misaligned state, only one of the divided valve cotters may move upward while being hooked on the upper end of the valve stem. In such a case, for example, when the upper end of the valve stem is guided to rise in the seat pressing member that presses the valve upper seat downward, the valve cotter is caught on the upper end of the valve stem and is not guided. Therefore, the operation abnormality of the valve cotter can be detected by checking whether or not the valve stem has risen to a predetermined position. When an abnormal operation of the valve cotter is detected in this way, the valve stub is pulled back once and the valve assembly operation to be fitted into the taper hole of the valve upper seat is repeated to give an opportunity for the valve cotter to operate normally. .

If the valve cotter does not operate normally even after repeating such a valve assembling operation, there is a possibility of defective parts. Therefore, the operation is stopped and an alarm is issued as necessary to notify the operator of the abnormality.

Therefore, according to the valve assembling method of the present invention, as compared with the conventional valve assembling method in which the valve assembling operation is uniformly repeated twice, the occurrence rate of the assembling error can be substantially the same or further reduced. In addition, if no assembly error occurs in the first valve assembly operation, the valve assembly operation is not wastefully repeated.

〔Example〕

One embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

This embodiment shows a case where an intake / exhaust valve is mounted on a cylinder head of a reciprocating engine. As shown in FIG. 1, the cylinder head 1 is supported so that the valve stem 3 is vertical in a state where the valve stem 3 of the valve 2 is passed through the intake port or the exhaust port. A valve lifting arm 4 is arranged below the valve 2. The valve push-up arm 4 is operated by the push-up cylinder 5 so as to push up the upper valve 2. Further, the valve lifting arm 4 is provided with a valve lift detector 6 which detects that the valve 2 has been pushed up to a predetermined position. An annular cotter engaging groove 7 is formed in the upper end portion of the valve stem 3 protruding toward the upper end side of the cylinder head 1. A valve spring 8 is fitted on the valve stem 3 protruding toward the upper end of the cylinder head 1. A seat pressing member 10 supported by the robot hand 9 is arranged above the valve stem 3. The sheet pressing member 10 is supported so as to be vertically movable with respect to the robot hand 9, and is biased upward by a pulling spring 11. Above the sheet pressing member 10, a pressing cylinder 12
Is placed, and the pulling spring is
The sheet pressing member 10 can be pushed down against the biasing force of 11. In addition, the robot hand 9 has a pressing cylinder.
A sheet pressing member rise detector 13 is provided which detects that the sheet pressing member 10 has been raised to a predetermined position by the pull-up spring 11 when the pressing release of the sheet 12 is released.
At the lower end of the seat pressing member 10, the valve upper seat 15
Is detachably supported by the clamp arm 14.
The lower surface of the valve upper seat 15 has a valve spring 8
Is a disk shape that supports the upper end of the, and a tapered hole 16 having a diameter that increases toward the top is formed in the center. The valve cotter 17 is previously installed in the taper hole 16 of the valve upper seat 15.
Is fitted. The valve cotter 17 has an annular engagement protrusion 18 on the inner circumference, and is formed in a tapered shape in which the outer diameter has the same gradient as the tapered hole 16 and the diameter increases toward the upper side. Further, the valve cotter 17 is divided into two parallel to the axial direction and can be expanded in the radial direction. A cotter guide hole 19 is formed in the center of the lower end of the seat pressing member 10 in the axial direction, and the diameter is smaller toward the lower end such that the vicinity of the lower end opening is connected to the taper hole 16 of the valve upper seat 15 which is supported downward. Is formed in a tapered shape. A cotter stopper 20 having a hole into which the upper end of the valve stem 3 can be fitted is disposed in the center of the cotter guide hole 19, and the cotter stopper 20 has a hole from the center of the hole. The guide rod 21 projects downward. The guide rod 21 is slidably supported up and down inside the cotter stopper 20 and is urged downward by a push-down spring 22.

A valve assembling method using the apparatus having the above structure will be described when the valve cotter 17 operates normally. First,
The sheet pressing member 10 is pushed down by the pushing cylinder 12. Then, as shown in FIG. 2A, the valve upper seat 15 is pushed down by the seat pushing member 10 and is pushed downward against the biasing force of the valve spring 8. Next, the push-up cylinder 5 is operated to push up the valve 2 with the valve push-up arm 4. Then, the valve upper seat
Since the valve 15 is pushed downward to some extent, the upper end of the valve stem 3 is located at the upper end of the valve stem 3 as shown in FIG. 2 (b) before the valve 2 comes into contact with the valve seat of the intake / exhaust port.
Fit into the taper hole 16 of 15. The upper end of the valve stem 3 fitted in the tapered hole 16 is caught by the engaging protrusion 18 of the valve cotter 17 and pushes up the valve cotter 17. And
As shown in FIG. 2 (c), the valve cotter 17 is guided by the tapered portions of the tapered hole 16 and the cotter guide hole 19 to move upward while being divided into right and left portions, and the cotter stopper 20.
Stops by touching the lower end of. When the valve cotter 17 is divided into the left and right, as shown in FIG.
The tip end of the valve cotter enters between the divided valve cotters 17, enters the cotter stopper 20, and further rises. The guide rod 21 rises in the cotter stopper 20 against the biasing force of the push-down spring 22 as the valve stem 3 rises. In this way, when the valve stem 3 rises to a predetermined position where the cotter engagement groove 7 of the valve stem 3 is located above the engagement protrusion 18 of the valve cotter 17, the valve push-up arm 4 finishes pushing up the valve 2. Then, the pressing cylinder 12 releases the pressing of the sheet pressing member 10. Then, as shown in FIG. 2 (e), the seat pressing member 10 rises and the valve upper seat 15 biased by the valve spring 8 rises along the valve stem 3. When the valve upper seat 15 is raised, the divided valve cotter 17 is also pushed up by the taper surface of the taper hole 16 and ascends along the valve stem 3 while receiving a force in the upward direction and in a direction in which they are aligned with each other. The protrusion 18 is the cotter engagement groove 7.
By fitting into the taper hole 16, it is completely fitted into the taper hole 16 and the left and right sides are surely aligned. Then, the valve upper seat 15 cannot push up the valve cotter 17 any more, and is securely attached to the valve stem 3.

Next, a case where an abnormality occurs in the operation of the valve cotter 17 will be described. From the state shown in FIG. 2 (b), the valve stem 3
When the upper end of the valve cotter pushes up the valve cotter 17 and the valve cotter 17 is not divided into left and right, as shown in FIG.
At the position where it abuts on the lower end of 20, the valve stem 3 also cannot be further raised with the upper end hooked on the engaging projection 18. Further, even when the valve stem 3 rises in a state where the valve stem 3 of the valve upper seat 15 is misaligned, one of the divided valve cotters 17 is placed at the upper end as shown in FIG. 3 (b). When the valve cotter 17 rises while being hooked, the valve cotter 17 cannot further rise at the position where it abuts on the lower end of the cotter stopper 20. Such abnormal operation of the valve cotter 17 is caused by the valve lift detector 6 when the valve 2 is pushed up by the valve pushing arm 4.
Can be detected by checking whether the valve 2 has risen to a predetermined position. When the valve rise detector 6 detects that the valve 2 has not risen to a predetermined position, the valve push-up arm 4 is once lowered, the guide rod 21 is pushed downward to pull down the valve stem 3, and then the valve push-up is performed again. The operation of pushing up the valve 2 with the arm 4 is repeated. When the valve cotter 17 does not operate normally even if the pushing operation of the valve 2 is repeated in this way, and the valve rising detector 6 detects again that the valve 2 has not risen to a predetermined position, there is a possibility of defective parts. Therefore, the work is stopped and an alarm is issued to notify the operator of the abnormality.

An abnormal operation of the valve cotter 17 is as shown in FIG. 3 (c) when the seat pressing member 1 rises from the state of FIG. 2 (d) and the valve upper seat 15 rises along the valve stem 3. In some cases, the lower end side of the valve cotter 17 may bite into the cotter engaging groove 7 without the engaging protrusion 18 of the valve cotter 17 fitting into the cotter engaging groove 7 of the valve stem 3. In this case, the valve cotter 17 is caught in the cotter engaging groove 7 so that the valve stem 3 is seated by the seat pressing member.
Because the cotter guide hole 19 of the sheet 10 is prevented from coming off, the sheet pressing member 10 is released even if the pressing down by the pressing cylinder 12 is released.
Cannot be raised regardless of the biasing force of the pull-up spring 11. Such an abnormal operation of the valve cotter 17 can be detected by checking whether or not the sheet pressing member rise detector 13 has raised the sheet pressing member 10 to a predetermined position. When the sheet pressing member rise detector 13 detects that the sheet pressing member 10 has not risen to the predetermined position, the pressing cylinder 12 again pushes down the sheet pressing member 10 and the valve pushing arm 4 pushes up the valve 2. . Even if the operation of pushing up the valve 2 is repeated in this way, the valve cotter 17 does not operate normally, and the sheet pressing member rise detector 13 again causes the sheet pressing member 10 to move.
When it is detected that is not raised to the predetermined position,
Since there is a possibility of defective parts, work is stopped and an alarm is issued to notify the operator of the abnormality.

The operation of the control device for controlling the valve assembling method will be described with reference to the flowchart of FIG.

In step 1 (hereinafter, the step is simply referred to as “S”), the robot is first moved forward and the sheet pressing member 10 supported by the robot hand 9 is arranged above the valve 2 inserted in the cylinder head 1. Next, the seat pressing member 10 supporting the valve upper seat 15 at the lower end is pressed down by the pressing cylinder 12 (S2). This sheet pressing member 10
When the valve upper seat 15 is pressed downward against the urging force of the valve spring 8 by pushing down, the valve pushing arm 4 pushes up the valve 2, and the valve cotter 17 is fitted in advance on the upper end of the valve stem 3. Fit into the tapered hole 16 of the valve upper seat 15 (S3).
When the pushing up is completed by this valve pushing arm 4,
The valve rise detector 6 detects whether the valve 2 has risen to a predetermined position (S4). The valve lift detector 6
When it is detected that the valve 2 has not risen to the predetermined position due to an abnormal operation of the valve cotter 17 without being turned on, it is determined whether or not this abnormal detection is the first time (S5).

If this is the first time that an abnormality has been detected, the valve cotter arm 4 should be returned to pull down the valve 2 once (S6), then return to S3 and perform the operation of pushing up the valve 2 again so that the valve cotter 17 can operate normally. give. If the abnormality is detected for the second time, the operator is notified of the abnormality by stopping the work and issuing an alarm (S7). When the valve rise detector 6 is turned on in S4 and it is detected that the valve 2 has risen to a predetermined position, the pressing by the pressing cylinder 12 is released and the sheet pressing member 10 is pulled up (S8). When the pressing by the pressing cylinder 12 is released, the sheet pressing member rise detector 13 detects whether or not the sheet pressing member 10 has risen to a predetermined position (S9). When it is detected that the sheet pressing member rise detector 13 does not turn on and the sheet pressing member 10 has not risen to a predetermined position due to an abnormal operation of the valve cotter 17, it is determined whether this abnormality detection is the first time. (S10). When the abnormality is detected for the first time, the process returns to S2, the sheet pressing member 10 is pressed down again, and a series of operations is repeated to give the barcotta 17 an opportunity to perform normal operation. When the abnormality is detected for the second time, the operator is notified of the abnormality by shifting to S7, stopping the work, and issuing an alarm. In S9, when the seat pressing member rise detector 13 is turned on and it is detected that the seat pressing member 10 has risen to a predetermined position, the valve cotter 17 operates normally and the valve upper seat 15 is attached to the valve stem 3. Therefore, the robot is retracted (S11) and the valve lifting arm 4 is pulled back (S1).
2) Complete the valve assembly process.

It should be noted that the detection of the abnormality by the valve lift detector 6 in S4 and the abnormality detection by the seat pressing member lift detector 13 in S9 correspond to the step of "detecting the operation of the valve cotter" which is a constituent feature of the present invention. In addition, the step of returning from S5 to S3 to S3 and pressing down the valve 2 again includes the operation of reassembling the valve when the valve stem does not rise to a predetermined position, which is a constituent feature of the present invention. "Repeat". In addition, S5 to S7
The steps up to (1) correspond to the step of "the operation can be stopped and an alarm can be issued when the abnormality of the valve cotter is not resolved even after repeating a proper number of times" which is a constituent feature of the present invention.

〔The invention's effect〕

As described above, the valve assembling method according to the present invention has the annular engaging projection on the inner circumference, is formed in a tapered shape with the outer diameter increasing toward the upper side, and is divided in parallel to the axial direction. The valve cotter is pre-fitted into a tapered hole in the valve upper seat that is located above the valve spring and has the same slope as the outer diameter of the valve cotter. A valve assembly method in which the valve projection is inserted into the tapered hole of the upper seat from the bottom and then pulled back again to fit the engagement protrusion of the valve cotter into the cotter engagement groove of the valve stem and attach the valve arper seat to the valve stem. At the time of the above-mentioned valve assembling operation, the operation of the valve cotter is detected and When an abnormality that does not occur, when the operation abnormality of the valve cotter persists even valve assembly repeats the operation again, repeating appropriate times,
It is a configuration that can stop the operation and issue an alarm.

According to this, since the valve cotter operation is detected and the valve assembly operation is repeated only when there is an abnormality that the valve stem does not rise to the predetermined position, the time cycle is wasted as in the conventional case. And the productivity of valve assembling work is improved.

[Brief description of drawings]

FIGS. 1 to 4 show an embodiment of the present invention. FIG. 1 is a partial sectional front view of a valve assembling apparatus, and FIGS. 2 (a) to (e) show a valve cotter. FIG. 4 is a partial vertical cross-sectional view showing the valve assembling operation in the case of normal operation, and FIGS. 4 is a flowchart showing the operation of a control device for controlling the valve assembling method. 1 is a cylinder head, 2 is a valve, 3 is a valve stem,
6 is a valve lift detector, 7 is a cotter engagement groove, 8 is a valve spring, 10 is a seat pressing member, 13 is a seat pressing member lift detector, 15 is a valve upper seat, 16 is a tapered hole, 17 is a valve cotter, 18 Is an engaging protrusion.

Claims (1)

[Claims] 1. An annular engaging projection is provided on the inner circumference,
The outer diameter is formed in a tapered shape with a larger diameter as it goes upward, and
The valve cotter, which is divided parallel to the axial direction, is pre-fitted into a taper with the same slope as the outer diameter of the valve cotter in the valve upper seat arranged above the valve spring, and an annular cotter engaging groove is formed on the upper end. By inserting the valve stem that you have into the taper hole of the valve upper seat from below and pulling it back again, the engaging protrusion of the valve cotter is fitted into the cotter engaging groove of the valve stem, and the valve stem is attached to the valve upper seat. In the valve assembling method for attaching the valve, when the valve cotter operation is detected during the above valve assembling operation, and the abnormality that the valve stem does not rise to the predetermined position occurs, repeat the valve assembling operation, and If the valve cotter malfunction does not disappear even after repeating this A method of assembling a valve, which can stop and issue an alarm.