JPS6368350A - Cam grinder - Google Patents

Abstract

PURPOSE:To correctly work a correct profile by suspending the cutting-in movement midway in the cutting-in course of a grindstone base and measuring the diameter of the base circle of a cam and obtaining the feed quantity on the basis of the difference between the set finishing dimension and the above-described measurement value and feeding the grindstone base on the basis of the feed quantity. CONSTITUTION:After the rough grinding, spark out, and rough grinding, a dimension device 31 is advanced, and spark-out is performed. At this time point, the revolution of a spindle 19 and the advance of a grindstone base 11 are suspended, and the diameter of the base circle of a cam is measured by the dimension device 31, and a measurement signal is input into an NC controller 40. Then, the coordinates at the present position of the grindstone base 11 is converted by the device 40 on the basis of the input signal, and then the dimension device 31 is retreated, and the position counter renewed by the coordinate conversion is read, and then fine and rough grinding, spark- out, finishing grinding, and spark-out are carried out, and work is finished. Therefore, by the correct grinding feed of the rest cut-out portion on the basis of the measured diameter dimension through the stop midway in the course, a correct cam shape can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a cam grinding machine controlled by a numerical control device.

<Prior art> In general, in a cam grinding machine controlled by a numerical control device, the rotational movement of the cam and the grinding wheel head are controlled based on numerical control data programmed in advance in the numerical control device. After rough grinding, coarse grinding, and sparking out of the cam on the camshaft by applying generating motion and cutting motion to Measure and grind until the diameter of the cam's base circle is the finished size.

Conventionally, the cycle for machining a cam on a camshaft using a cam grinder is as shown in Figure 11, in which the cam grinding process is performed in sequence: 1 barqua, 1st grinding, fine rough grinding, and spark out g grinding, and then the cam grinding process. The diameter of the base circle was measured with a sizing device, then finish grinding was performed until a sizing signal was output, and then the shape was adjusted by sparking out.

<Problems to be Solved by the Invention> However, in this conventional method, in the finish grinding shown in FIG. 11, as shown in FIGS. Since we are grinding and measuring the diameter of the cam's base circle using a sizing device at the same time,
As shown in Fig. 13 (al), the sizing signal from the sizing device determines when the diameter A of the base circle of the cam to be actually ground becomes equal to the prespecified cam base circle diameter B. A size signal is generated, but in this case, the half PI!Bl,B2 of the base circle of the cam to be ground is B1=B2, whereas the radius A1 with respect to the true center of the base circle of the cam to be actually ground is .A2 has the problem that A1≠A2, which makes it impossible to accurately measure the base circle diameter of the cam.

Furthermore, in the case of a device that adjusts the shape of the cam by sparking out after the sizing signal is output, Fig. 13 (
As shown in 'b), the circumference of the cam is uniformly shaved off by α, so the diameter A' of the base circle of the actually finished cam is A'
=A-2α, and there is a problem in accuracy that the actual cam shape is smaller than the desired cam shape.

Means for Solving the Problems> The present invention has been made to solve the problems of the conventional art, and as shown in FIG. , a measuring device 2 that measures changes in the diameter or radius of the perfect circular part of the cam during grinding, an α1 constant signal control device 4 that reads signals from the measuring device, and a finished dimension specified by numerical control data. A feed distortion calculation device 5 calculates the feed amount to the finished dimension by subtracting the measured value of the measuring device, and a fixed feed of the grinding wheel head 3 until the perfect circular part of the cam reaches the finished dimension based on the calculation result of the feed distortion calculation device. The present invention is characterized in that it is provided with a quantitative feed control device 6 for controlling.

With the above configuration, the cutting movement of the grinding wheelhead is stopped midway through the cutting movement, the diameter of the base circle of the cam is measured by the measuring device, and 'IJiJ A cam with an accurate cam profile can be machined by subtracting the measured value of the measuring device to find the feed amount to the finished dimension, and then feeding the grindstone head a fixed amount based on this feed amount.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 2, reference numeral 10 indicates a bed of a cam grinding machine, and a grindstone head 11 is placed on this bed so as to be movable forward and backward. A grinding wheel 12 is rotatably supported on a grinding wheel head 11,
This grinding wheel 12 is rotationally driven by a drive motor 13 installed on the grinding wheel head 11 via a belt transmission device 14. The grindstone head 11 is moved forward and backward by a feeding mechanism using a servo motor 15 as a driving source.

Further, a table 16 is placed on the bed 1O so as to be slidable in a direction perpendicular to the advancing and retreating direction of the grindstone head 11, and is indexed by an indexing device in an enclosure. A headstock 17 and a tailstock 18 are mounted and supported on the table 16, and a camshaft W is rotatably supported between the headstock center 20 on the main shaft 19 of the headstock 17 and the tailstock center 21. It is now possible to do so. The main shaft 19 and the camshaft W are integrally driven to rotate by a main shaft drive motor 22 installed on the table 16.

A sizing device 31 equipped with a feeler 30 is installed on the table 16, and as shown in FIG. When the diameter of the base circle is measured, a sizing signal is output to the numerical control device 40.

40 distributes pulses to a drive unit 41 that drives the servo motor 15 to control the feeding of the grindstone head 11, distributes pulses to a drive unit 42 that drives the spindle drive motor 22 to control the rotation of the spindle 19, and controls the rotation of the spindle 19. Device 3
This numerical controller 40 mainly controls a central processing unit 43, a memory 44, a pulse distributor 45, an input device 46, and an interface 47. It is configured.

The output of the sizing device 31 that measures the base circle diameter of the cam on the camshaft W is input to the central processing unit 43 via the ink face 47.

A cutting program and profile data for grinding the cam on the camshaft W are inputted by the input device 46 and stored in the memory 44 via the central processing unit 43.

Next, in the above configuration, a cycle for grinding the cam on the camshaft W will be explained based on FIGS. 4 to 9.

First, before machining the camshaft W, the grindstone head 11 is stored in the memory 44 from the input device 46 via the central processing unit 43.
The feed rate F, target finishing diameter D, rotational speed S of the spindle 19, etc., and profile data are stored.

When the program setting operation is completed, the camshaft W is set between the headstock center 20 and the tailstock center 21. When the start button of the circuit is pressed, the cam on the camshaft W is ground according to the cycle shown in FIG.

This cycle is to continuously perform rough grinding to finish grinding of the cam on the camshaft W, and is basically a rough grinding process in which the cam on the camshaft W is grinded with high efficiency to obtain the largest possible machining allowance without causing major damage to the grinding wheel 12. , the uncut portion 130 shown in FIG. 5(a) of the cam side portion generated during this rough grinding.
λ spark out to remove the quench crack layer generated in the rough grinding, spark out to remove the uncut portion 130 of the cam side portion generated in this rough grinding, and the sizing device 31 to remove the cam side. Measurement of the diameter of the base circle, coordinate conversion to convert the coordinates of the current position of the grindstone based on the measurement results, fine rough grinding to remove the quench crack layer generated in the rough grinding, and this fine rough grinding. The process consists of spark-out to remove the residual material 130 on the cam side that is generated, finish grinding to improve the surface roughness and profile accuracy of the cam, and spark-out to remove the residual material 130 on the cam side that is generated in the final grinding. ing.

The above cycle is performed by the numerical controller 40 according to the flow shown in FIG.
It is executed by processing.

Prior to this process, the Canadian program and profile data are read into the central processing unit 43 from the memory 44,
As soon as the start-up button is pressed, rough grinding shown in step 50 in FIG. 6 is started.

FIG. 7 shows the detailed flow of step 50. First, in step 70, the target finishing diameter D1 and feed rate F1 are read from the memory 44, and in step 71, the current position of the grinding wheel head 11 is determined by the current position counter 140 of the central processing unit 43. is counted and stored in the memory 44, and the grindstone head 11
The current position of is read from the memory 44. Next step 72
Then, the value obtained by subtracting the target finishing diameter DI from the content C of the current position counter and dividing by 2 is converted as the depth of cut. Here, since the target finishing diameter D1 and the content C of the current position counter 140 are expressed by the diameter value of the cam base circle, the feed amount of the grindstone head 11 is half of that value. In step 73, the depth of cut per unit angle is calculated, and in step 74, the profile data is calculated as shown in Fig. 5(b).
-■-・Cam top■ of the lift part (■→■-■ part)
→■-・■ is read out in the order, and in step 75 the cutting amount per unit angle is added to this profile data, and in step 76 this data is subjected to pulse distribution processing to the pulse distributor 45, so that the drive units 41 and 42 As a result, the servo motors 15 and 22 are driven, and in step 77 it is determined whether the pulse distribution in step 76 has been completed, and if not, it is waited until the pulse distribution is completed, and in step 78, the profile data is If it has been read to the end, it is determined in step 79 whether the full depth of cut has been completed, and if it has not been completed, the profile data is transferred to the cam base in the next step 80 (Fig. 5 (G)). From inside■-
The process returns to step 74 so that the data can be read out in the order of (1) - (2), and if it has been completed, the next step 51, spark out, is performed.

The next step 51 is a spark out to remove the uncut portion 130 on the side part caused by the rough grinding in step 50.
The details of this step 51 are executed according to the flow shown in FIG. 8, and in step 9o, the profile data is
BL inside cam base ■-■-・cam top ■-■→■
In step 91, the profile data read in step 90 is pulse distributed to the pulse distributor 45 to operate the drive units 41 and 42.
The servomorph 15.22 is driven, and in step 92 it is determined whether the pulse distribution in step 91 has been completed. If not, the process waits until the pulse distribution is completed. In step 93, it is determined whether the profile data has been read to the end. If the camshaft W has been read to the end, it is determined in step 94 that the camshaft W has been rotated the specified number of times, and if the camshaft W has not been rotated the specified number of times, in the next step 95, the profile data is Return to step 9o so that it can be read from the circle ■,
If it has rotated the designated number of times, rough grinding in the next step 52 is performed.

In this step 52, similar to step 50, rough grinding is performed by executing the detailed flow shown in FIG. 7.

Step 53 is performed as shown in FIG.
As shown in a), the sizing device 31, which had been retracted, is moved to the cylinder 4.
It is moved forward by the piston 49 of No. 8.

In step 54, as in step 51, the eighth
By executing the flow shown in the figure, spark-out is performed. When this spark-out is completed, the pulse distribution process has been completed, and the rotation of the main shaft 19 and the advancement of the grinding wheel head 11 have stopped. Inside the base of the grinding wheel 12 and cam at this time.

The positional relationship of the feeler 30 of the sizing device 31 is shown in Fig. 3(b).
It looks like this.

In step 55, when the base circle diameter of the cam at the time when step 54 is completed, the sizing device 30 sends sizing signals (IP, 2P, 3P,
4P, 5P) are set by +20μ, +40μ, +60μ, +80μ, +100 from a certain reference value φD, respectively.
μ is set in advance so that the measured value is + from the reference value φD.
If the sizing signal 3P of 60 μ is output, the sizing device 3
A signal from 1 to 11100 is output to the numerical control device 40. This signal is then input to the central processing unit 43 of the numerical control device 40 via the ink face 47.

Next, in step 56, it is determined which signal among IP to 5P the signal read in step 55 is. For example, if the sizing signal 3P is the same as in step 55, this sizing signal 3P is output. The range of setting values set in advance for
A process of adding the median value of 60μ to +40μ to the reference value is performed, and this value is updated to the content C of the current position counter 140, thereby completing the coordinate transformation.

This process is performed by executing the flow shown in FIG. 10 in the arithmetic processing unit 43. Step 100-1
Step 05 determines whether the signal output from the sizing device 31 is one of the preset sizing signals 1P to 5P, and in steps 106 to 110, the sizing signals IP to 5 are set to the target reference value φD.
The median value (αl
−α5) is added. Next, in step 111, the content C of the current position counter 140 is updated by using this added value as a position signal indicating the current position of the grindstone head 11.

In the next step 57, the sizing device 31 is moved back.

In step 58, fine rough grinding is performed by executing the same flow shown in FIG. 7 as in step 50, except that the content C of the current position counter updated by the coordinate transformation in step 56 is read out.

In step 59, spark-out is performed by executing the same flow shown in FIG. 8 as in step 51.

In step 60, finish grinding is performed by executing the process shown in FIG. 7, which is similar to step 58.

In step 61, spark-out is performed each time the flow shown in FIG. 3 similar to step 51 is executed.

The cam on the camshaft is ground by the above steps.

Here, in each step of the fine rough grinding and finish grinding, the diameter dimension measured in the mid-stop state is used as a reference to accurately grind and feed the remaining portion, so that the cam accurately matches the target finish dimension. Can grind cams of any shape.

<Effects of the Invention> As described above, in the present invention, the diameter of the cam base circle after rough grinding and spark out of the cam on the camshaft and spark out is measured by a sizing device,
The coordinates were exchanged from the diameter of the measured cam base circle to the coordinates indicating the feed amount of the grinding wheel head to the finishing dimension of the cam base circle diameter, and this coordinate exchanged value was updated to the current position counter indicating the current position of the grinding wheel head. Compared to methods that perform finish grinding while measuring the diameter of the cam base circle, it has the feature of improving the accuracy of the cam shape. Furthermore, the present invention has the feature that it is possible to prevent the cam shape from becoming smaller than what is actually being ground.

In addition, as a ripple effect, the precision of cam shapes has improved, which has resulted in improvements in the precision of camshafts used in engine camshafts.
Since accurate valve opening and closing can be achieved, fuel efficiency can be improved.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing the configuration of the present invention, FIG. 3 is a diagram showing a state in which the diameter of the cam base circle is measured by a sizing device, FIG. 4 is a diagram showing the grinding cycle of the present invention, and FIG. a) is a diagram showing the uncut portion of the cam, Figure 5(b) is a diagram showing the order of reading the profile data, Figure 6 is the flow of Figure 4, and Figure 7 is rough grinding, coarse grinding, and fine rough grinding. , Finish grinding flow, Part 8
The figure shows the flow of spark out, Figure 9 shows the output signal of the sizing device, Figure 10 shows the flow of coordinate conversion, Figure 11 shows the conventional grinding cycle, and Figures 12 and 13 show the conventional cam base. A diagram showing a state in which the diameter of a circle is measured. 1.40... Numerical control device, 2... Measuring device, 3.
11... Grindstone head, 15.22... Servo motor, 3
0... Feeler, 31... Sizing device, W... Camshaft.

Claims (1)

[Claims] In a cam grinding machine that grinds a cam on a camshaft by giving a rotational motion to a camshaft and generating motion and cutting motion to a grindstone head based on numerical control data programmed in advance in a numerical control device, A measuring device that stops the cutting motion midway through the cutting motion and measures a change in the diameter or radius of the circular portion of the cam due to the grinding process, and a measurement signal control device that reads the signal of the measuring device. a feed amount calculation device that calculates the feed amount to the finished dimension by subtracting the measured value of the measuring device from the finished dimension specified by the numerical control data; A cam grinding machine equipped with a constant feed control device that controls the constant feed of the grinding wheel head until the perfect circle part reaches the finished size.