JPH04152026A - Direction judging method of valve guide for part press-in device to cylinder head - Google Patents

Abstract

PURPOSE:To assemble a valve guide surely and efficiently without mistaking the press-in direction by advancing a robot hand to the specified position at the specified height, and confirming the reverse direction when the proximity switch of a detecting lever is kept on. CONSTITUTION:A robot hand 1 and the teaching height are set so that a chuck center 0, a wrist rotary shaft 3 provided in the advance direction of the robot hand 1 and the length center of a valve guide 12 are made the same height. Adjustment is made so that a proximity switch 11 is turned off when a contact 10 is thrust into the valve guide 12 by about 0.2-0.3mm. When the valve guide 12 is held in the reverse direction, the robot hand 1 is advanced to the specified position at the specified height, however a gap is generated between the outer periphery of the valve guide 12 and the contact 10 due to different shapes, a detecting lever system 6 is not operated, the proximity switch 11 is kept on, and the reverse direction can be confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve guide for a cylinder head of a four-stroke engine, and more specifically, a method for determining the direction of a valve guide in a device for press-fitting parts into a cylinder head for two or four wheels. Regarding.

(Prior art) For example, a cylinder head a of a four-cycle vehicle as shown in Fig. 3 is provided with intake and exhaust valves b and c, and when the head d contacts a valve seat C, It closes and opens when you move away from it. This valve b,
The reciprocating motion to open and close c is performed by the rotation of a camshaft (not shown), but in order to perform the reciprocating motion without wobbling about the valve axis, valves b and c are usually inserted into a valve guide f having a long shaft 1. The inner circumference of the valve guide f is used as a guide to reciprocate.

The valve guide f is formed into an elongated cylindrical shape and is press-fitted into a hole provided in the cylinder head. Although the shapes are different at the upper and lower ends as shown in the figure, since the same diameter portions are long, there is a risk that the upper and lower ends may be incorrectly assembled into the cylinder head a.

On the other hand, due to the mass production involved in assembling such parts, unmanned assembly systems such as robots are used.

Therefore, in order to distinguish between the upper and lower parts, conventional methods have been to install a discrimination function within the parts feeder, or to measure the outer diameter of the tip because the shape of the tip differs between the upper and lower parts.

(Problem to be solved by the invention) However, if a discrimination function is provided inside the parts feeder, the mechanism will need to be replaced when changing models, and the discrimination function itself will be expensive. To measure this, a new measuring device is required on the line.
This requires a large amount of space and is also expensive.Furthermore, direct measurement using a proximity switch may be considered, but this method is problematic because it may result in incorrect determination.

In view of this, and in order to eliminate the above-mentioned drawbacks, the present invention provides a method for determining the direction of a valve guide in a device for press-fitting parts into a cylinder head, which allows the press-fitting direction to be reliably performed without making a mistake, thereby improving the efficiency of assembly work. This was done for the purpose of achieving this goal.

(Means and effects for solving the problem) In order to achieve the above object, the present invention grips the longitudinal middle part of the valve guide from the parts feeder escape section with a chuck at the tip of the robot hand, and the center of the chuck and the robot hand Set the robot hand and teaching height so that the wrist rotation axis and the center of the length of the valve guide are on the same line, and when the robot hand is advanced to the specified height and position, the detection lever If the proximity switch is turned off, the normal direction is confirmed,
If the switch remains ON, the reverse direction is confirmed, and the valve guide held by the robot hand is reversed and held in the normal direction.

(Example) The present invention will be described below with reference to an example shown in FIGS. 1 and 2.

The method for determining the direction of a valve guide in the apparatus for press-fitting parts into a cylinder head according to the present invention is carried out using the following direction determining device, so first, the device will be explained.

At the tip of the robot hand 1, there is a chuck 2 that can be opened and closed.
2, and when this chuck 2.2 moves toward the center, it can grip an article such as a valve guide at an intermediate position in the longitudinal direction.

Further, the robot hand 1 can rotate around the wrist rotation axis 3 and can move in the direction of the rotation axis 3.

A parts feeder (not shown) is provided in the upper part between the chucks 2, 2, and is adapted to receive parts from this escape section.

Below the chuck 2 there is a support 4 fixed to a base (not shown) with bolts 5 or the like, and a detection lever mechanism 6 is provided on the top of the support 4.

The detection lever mechanism 6 consists of a fixed part 7 and a movable part 8, and a fulcrum 9 is provided between the two so that the movable part 8 can be rotated with respect to the fixed part 7.

The movable part 8 consists of a short vertical piece 8a and a relatively long horizontal piece 8b, and a contact 10 is provided at the top end of the vertical piece 8a so that it can be moved in and out by screwing. The end of the horizontal piece 8b is opposed to the proximity switch 11.

When the chucks 2, 2 grip the valve guide 12, the contactor 10 is located at the bottom of the chuck 2 as shown in FIG.
As shown in a) and (b), the valve guide 12 comes into contact with the lower outer diameter of the valve guide 12, and the movement at the contact point is expanded by the lever through the fulcrum 9 and transmitted to the horizontal piece 8b, causing the proximity switch to move. 11.

The proximity switch 11 is connected to a determining device (not shown).

Next, a determination method using this valve guide press-fitting direction determination device will be explained.

The chucks 2, 2 at the tip of the robot hand 1 are fed from the parts feeder and grip the longitudinally intermediate portion of the valve guide 12 from the escape portion.

At this time, the robot hand 1 and the teaching height are set so that the chuck center 0, the wrist rotation axis 3 provided in the advancing direction of the robot hand 1, and the center of the length of the valve guide 12 are the same.

That is, by chucking the center of the length of the valve guide 12, the end portions will be in the same position even when the valve guide 12 is reversed, which simplifies teaching.

Then, the contactor 10 is attached to the valve guide 12 by 0.2
Proximity switch 11 turns OFF when pushed ~0.3mm
Adjust it so that it becomes .

If the valve guide 12 is held in the correct direction, the robot hand 1 moves forward to a specified position at a specified height.

When the outer periphery of the valve guide 12 comes into contact with the contactor 10 as shown in FIG. 2(a), the horizontal piece 8b of the detection lever mechanism 6 is lowered and separated from the proximity switch 11, so that the proximity switch 11 is turned OFF. . Therefore, in this case, since no abnormality is detected, the valve guide 12 is sent to the next process as it is.

Furthermore, even when the valve guide 12 is gripped in the reverse direction, the robot hand 1 moves forward to the specified position at the specified height.

In this case, at a position that satisfies the range of 0.2 to 0.3 shown in the figure, a gap is created between the outer periphery of the valve guide 12 and the contactor 10 due to the difference in shape as shown in FIG. 2(b). Since the detection lever mechanism 6 does not move, the proximity switch 11 remains ON, thus confirming the reverse direction.

As a result, the robot hand 1 moves to a position where there are no interfering objects such as the detection lever mechanism 6, and rotates the wrist rotation shaft 3 by 180@.

Then, by repeating the operation (■) again, it is confirmed that the direction is in the positive direction.

However, if there is no change in the detection lever mechanism 6 (the proximity switch 11 remains ON) even after the second operation (2), the product is handled separately as a different product.

(Effects of the Invention) As explained above, the present invention can easily determine the forward and reverse directions of the valve guide, so even if the model (valve guide thickness, etc.) changes, no setup is required, and
Since the amount of change in detection is expanded by the detection lever mechanism, the ON/OFF operation of the proximity switch is stabilized, and the device itself for carrying out the present invention is simple and can be provided at low cost. Furthermore, even if it is determined that the direction is different, it has excellent effects such as being able to check again simply by reversing the direction.

[Brief explanation of drawings]

FIG. 1 shows the chuck part of the robot hand and the detection lever mechanism part of the parts press-in device to which the present invention is applied, and (a
) is a side view, (b) is a plan view, (C) is a front view of the detection lever mechanism, FIG. 2 is a state diagram of direction discrimination when using the device in FIG. 1, and (a) is a diagram of the direction discrimination state. FIG. 3 is a sectional view showing the relationship between the current cylinder head, intake and exhaust valves, and valve guides. 1... Robot hand, 2... Chuck, 3...
Wrist rotation axis, 4... Support, 5... Bolt, 6...
Detection lever mechanism, 7... Fixed part, 8... Movable part, 8
a... Vertical piece, 8b... Horizontal piece, 9... Fulcrum, 1
0...Contactor, 11...Proximity switch, 12...
valve guide.

Claims (1)

[Claims] Grip the longitudinal middle part of the valve guide from the parts feeder escape part with the chuck at the tip of the robot hand, and hold the robot hand so that the center of the chuck, the wrist rotation axis of the robot hand, and the center of the length of the valve guide are on the same line. When the robot hand is advanced to the specified height and position by setting the robot hand and teaching height, if the proximity switch of the detection lever turns OFF, the normal direction is confirmed, and if the switch remains ON. A method for determining the direction of a valve guide in an apparatus for press-fitting parts into a cylinder head, characterized in that the reverse direction is confirmed and the valve guide gripped by the robot hand inverted is set as the normal direction.