JPH0749374Y2 - Valve clearance checker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a valve clearance checker.

[Conventional technology]

Conventionally, a valve clearance measuring machine detects an angle of rotation of a cam by an encoder and presets an angle at which the cam top contacts the valve lifter and an angle rotated by 180 ° (the position where the cam bottom comes to the upper part of the valve lifter) from that angle. The valve lift amount at each angle is read by, for example, a length measuring device using a differential transformer.

The valve clearance α is calculated by the formula (1) using the difference X between the cam top and the cam bottom, and α = Y− (A × X + B) (1) where Y: clearance is 0 Valve lift A, B: Measurement system correction coefficient Pass / fail judgment and clearance value are set to 7 segments, for example.
The value was displayed on a numerical display consisting of an LED, etc.
-48807 gazette).

[Problems to be solved by the invention]

However, the above-mentioned conventional valve clearance measuring machine measures the position of the cam top obtained from the product drawing at only one point. Therefore, the machining tolerance of the cam top position is actually ± 0.05 mm, which causes a difference from the measured value at the true cam top position, as well as the camshaft deflection and the camshaft bearing (journal). Despite the tendency or biased error due to the clearance of the cam cap, which is the bearing that supports the bearing of the camshaft, the measurement results are displayed, for example, by a numerical indicator consisting of a 7-segment LED or the like. Since it was carried out in, the amount of information was small, and it was difficult to understand because it was displayed as symbols and so on, and it was not sufficient to obtain a clear and reliable judgment.

The present invention has been made based on such a situation, and an object thereof is to provide a valve clearance checker which can make a clear and reliable determination without error.

[Means for solving problems]

In order to achieve such an objective, in order to measure the distance L ₁ between the cam top and the valve bottom of the workpiece to be measured and the distance L ₂ between the cam bottom and the valve bottom, the cam contactor is fixed at one end and the other end A measuring frame having a valve contactor slidably attached to the valve, a measuring means having one sensor connected to the valve contactor for detecting the amount of movement, and a predetermined measurement centering on the cam top and the cam bottom. Means for limiting the angle range, means for outputting the measurement time range at the center of the cam top and the bottom of the cam by the measurement angle range limiting means, and L ₁ , sampled and measured at fixed time intervals within the measurement time range by the measuring means, A means for calculating the valve clearance of the workpiece to be measured from the maximum value of each L _2, the valve clearance of the workpiece to be measured, and the specified valve clearance standard value And means for displaying the result of comparison with.

[Action]

In this way, a measurement instruction is issued for a range that has a certain spread around the cam top and cam bottom, the valve lift amount within this measurement range is sampled at fixed time intervals, and the maximum value is calculated from this sampled value. Since the valve clearance of the work is calculated and the comparison result with the valve clearance standard value of the master work is displayed, accurate measurement is possible even if the cam top position is displaced due to the machining tolerance of each work. You can get the value.

[Embodiment] An embodiment of the valve clearance checking machine according to the present invention will be described below.

FIG. 1 is a block diagram showing an embodiment of a valve clearance checking machine according to the present invention. In the figure, there is a sensor 6 for measuring the valve lift amount. As the sensor 6, for example, a measuring instrument using a differential transformer is used.
The electric signal from the sensor 6 is converted into a digital signal through the differential transformer amplifier 12, and the CPU 15 through the CPU bus.
It is designed to be input to.

The sensor 6 contacts the valve bottom surface 23 so as to detect the displacement of the valve lifter 5 corresponding to the valve lift amount,
Measuring frame connected to the sliding valve contact 22
The displacement of the valve lifter 5 mounted on 25 is made by the rotating cam 3. The dog 4 is coaxial with the cam 3.
The dog is adapted to determine the measuring range of the cam top and the cam bottom, and the cam top measuring area sensor 1 and the cam bottom measuring area sensor 2 for detecting this range are provided. Proximity switches or the like are used as the sensors 1 and 2. The outputs of the sensors 1 and 2 are passed through an isolation interface 9 for insulating from the outside by using a photo coupler or the like,
Furthermore, it is adapted to be input to the CPU 15 via the CPU bus.

There is also a keyboard 7, which is used to input the standard value of the valve clearance and the set value of the tolerance in the master work, and also has the role of a switch for switching the screen of the CRT 8 which will be described later, and through the keyboard interface 10. Connected to CPU15. The C
RT8 is designed to display each value set value, measurement result and graph that statistically processed valve clearance,
It is connected to the CPU 15 via a CRT interface 11.

In addition, there is a sequencer 16, and this sequencer 16 and CPU1
Between 5 is an input / output interface 13 for transmitting and receiving signals. Further, it is provided with a memory 14 which temporarily or long-term stores each measurement result and semi-permanently stores a control program of this apparatus.

The operation of the valve clearance checking machine configured as described above will be described below.

The cam 3 is rotated by a drive motor or the like, and the dog 4 provided for each cam 3 and limiting the cam top range or the cam bottom range turns on the cam top measurement area sensor 1 or the cam bottom measurement area sensor 2. During this ON
The output of the sensor 6 for detecting the valve lift amount is passed through the differential transformer amplifier 12 to the memory 14 at a constant sampling cycle.
To remember. FIGS. 2 (1) and 2 (2) respectively show the timing when the cam top measurement area sensor 14 detects the beginning and end of the cam top range. When the cam top measurement area sensor 1 is turned off (FIG. 2 (2)), sampling is stopped, the maximum value of the valve lift amount sampled in that area is calculated, and this value is stored in the memory 14, and Output a measurement complete signal to the sequencer 16.

FIG. 3 (a) is a cam top measurement instruction signal output from the cam top measurement area sensor 1, and shows the lift amount within the drive time from FIG. 2 (1) to FIG. 2 (2). As shown in FIG. 3 (b), the sampling signal is
For example, it is sent every 20 msec. When the output of the cam top measurement area sensor 1 is turned off, as shown in FIG. 3 (c), after the time for calculating the maximum value of the sampled valve lift amount is given, the cam top measurement completion signal is given. Is sent.

Similarly, as shown in FIG. 2 (3), even when the cam bottom measurement area sensor 2 detects the beginning of the cam bottom range, sampling is performed in the process shown in FIG. 2 (4) as described above, After that, the maximum value is calculated.

Such an operation is sequentially performed for each cam, and a series of time series changes thereof is shown in FIG.

FIG. 5 shows the principle of valve clearance measurement. A cam contact 21 is fixed to one end of the measuring frame 25, a valve contact 22 is slidably attached to the other end, and one sensor 6 for detecting the amount of movement is connected to the valve contact 22. Has been done. A clearance adjusting shim 24 is fitted on the valve lifter 5, and the a dimension is the major axis of the cam, and the b dimension is the total length of the valve + valve lifter + shim, both of which are constant values for each workpiece to be measured. In FIG. 5 (A), the cam top is in contact with the cam contactor 21, and the length L ₁ from the position of the cam top to the valve bottom surface 23 at this time is relative to the dimension of the master work. In order to know, the value X ₁ of the sensor 6 for moving amount measurement is read. The sensor 6 is a spacing between the cam contact 21 and the valve contact 22, shown in of FIG. 5 (C), the sum of design values b ₁ of the major axis of the design value a ₁ and the shim + lifters + valve cam It is set so that the reading value when measuring a master work having a length of 0 becomes 0. Further, in FIG. 5B, the cam top is the valve lifter 5
In this case, the length L ₂ from the cam bottom position to the valve bottom surface 23 at this time is shown relative to the master work, and the value X _{2 of the} sensor 6 is read.

If the valve clearance is c in FIG. 5 (A), the following relational expression holds from these measured values.

L ₁ = a + b + c = a ₁ + b ₁ + X ₁ (2) L ₂ = a + b = a ₁ + b ₁ + X ₂ (3) Therefore, the valve clearance c of the workpiece to be measured is c = L ₁ -L ₂ = X ₁ −X ₂ (4) In this way, the cam contactor 21 uses the output value of the sensor 6 when the cam top and the cam bottom are in contact, regardless of the machining tolerance of each workpiece. The valve clearance c of the work can be measured.

The output value of the sensor 6 when the cam top as shown in FIG. 1 is right above is set to the maximum value L _{1 of the} distance between the cam top and the valve bottom surface, and the cam top as shown in FIG. If the output value of the sensor 6 when it is right below is the maximum value L _{2 of the} distance between the cam bottom and the valve bottom surface, the maximum value L _{11 to} L _1n of the cam top and the maximum value L of the cam bottom of each cam _{1 to n} are set. ₂₁ ~ L
_2n is calculated by the CPU 15, and then the valve clearance c _n of each work is calculated according to the following equation (5), and c _n = L _1n −L _2n ……… (5) The result is passed through the CRT interface 11. Display on CRT8. Further, the valve clearance standard value of the master work and the deviation from the intersection, which are input by the operator or the like from the keyboard 7 through the keyboard interface 10 in advance, are displayed in numerical values, a graph, and a pass / fail judgment in accordance with the CRT 8. . At this time, at the same time, the determination result is output to the sequencer 16 via the input / output interface 13.

This series of operations is performed every time a work arrives, and the resulting valve clearance value for each valve and its pass / fail are stored in memory in a time series, and when an operator or the like wants to check the finish tendency of the work, etc. , Can be displayed on CRT8. In this case, the horizontal axis shows the work No. (the newest one is 1, and the numbers increase from left to right), and the vertical axis shows the valve clearance value (green inside tolerance, red outside tolerance, for example). Is displayed) and is plotted with, for example, a "*" mark.

In addition, the difference between the valve clearance value and the standard value of each valve input in advance from the keyboard is output to the shim selector in the previous step as a correction value for each valve.

As described above, according to the valve clearance checker described above, the cam top and the cam bottom of the cam are within a predetermined range (for example, ± 15 from the cam top and the cam bottom in the product drawing).
The maximum value in the range (° range) is used as the valve lift amount.Therefore, the error due to the deviation of the measurement position caused by the machining tolerance of the cam for each work is eliminated, and the camshaft deflection, the cam cap oil clearance, etc. It is possible to detect the tendency and bias of the measured values and improve the measurement accuracy.

In addition, various product-specific specified values, tolerances, etc. can be arbitrarily set with the keyboard using these as parameters, so they may be diverted to another product production line or changed. Also, it becomes possible to easily cope with the problem in an extremely short time.

Also, for example, statistical processing of the past several hundred units can be performed, and the results can be displayed on the CRT, so that changes in the process can be understood and equipment failure or product failure can be prevented in advance.

Furthermore, since the measured valve clearance values of the products are averaged in units of a certain number of units and the difference from the specified value is output in the process, it is possible to perform correction so as to always approach the standard value.

[Effect of device]

As is clear from the above description, according to the valve clearance checker of the present invention, the sampling range can be limited by only detecting the dog shape corresponding to the cam measurement range by the sensor, and therefore the measurement skip may occur. It is possible to inexpensively provide a highly reliable measurement system that does not have any problems.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a valve clearance checking machine according to the present invention, and FIGS. 2 (1) to (4) are
FIG. 3 is a block diagram showing an embodiment of a valve clearance detecting mechanism according to the present invention, FIG. 3 is a diagram showing timings of signals which can be taken out by the mechanism shown in FIG. 2, and FIG. FIGS. 5 (A), 5 (B) and 5 (C) showing the timing of signals are diagrams showing the principle of valve clearance measurement according to the present invention. 1 ... Cam top measurement area sensor, 2 ... Cam bottom measurement area sensor, 3 ... Cam, 4 ... Dog, 5 ... Valve lifter, 6 ... Sensor, 7 ... Keyboard, 8 ... CR
T, 16 …… Sequencer, 21 …… Cam contact, 22 …… Valve contact, 23 …… Valve bottom, 24 …… Sim, 25 …… Measuring frame.

Continued Front Page (72) Inventor Hidetoshi Takano 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (56) References JP 60-262007 (JP, A) JP 55-144701 (JP, A) JP-A-53-149059 (JP, A) JP-A-53-38348 (JP, A) Actually opened 61-155714 (JP, U) Actually opened 58-47114 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A cam contactor is fixed at one end and a valve contactor is provided at the other end to measure a distance L ₁ between a cam top and a valve bottom surface of a workpiece to be measured and a distance L ₂ between a cam bottom and a valve bottom surface. Measuring means provided with a slidably mounted measuring frame and one sensor connected to the valve contactor to detect the amount of movement thereof, and a predetermined measuring angle range is limited around the cam top and cam bottom. Means for outputting the measurement time range of the center of the cam top and the cam bottom by the measurement angle range limiting means, and L ₁ , L ₂ sampled and measured at fixed time intervals within the measurement time range by the measurement means. A means for calculating the valve clearance of the workpiece to be measured from each maximum value, and the result of comparison between the valve clearance of the workpiece to be measured and a predetermined valve clearance standard value. And a means for displaying the valve clearance check machine.