JPS63267154A - Grinding method for cam - Google Patents

Abstract

PURPOSE:To reduce the grinding time of a cam by cutting a cam material by means of the oscillation of an oscillating table with respect to a grinding wheel which is previously positioned on an cutting advancing end and, after that, bringing a master cam into contact with a follower roller. CONSTITUTION:As a starting switch is pressed, a motor 19 is rotated at a low speed and a cam material W supported in the center by a main spindle 33 is rotated at a low speed. After the rotation of the main spindle 33 is started, an oscillating table 14 is oscillated and the cam material W is advanced toward the grinding wheel 3 positioned on a cutting advancing end, to give a rough grinding cutting to the cam material W. When the cam material W is cut up to the rough grinding cutting advancing end, a master cam is brought into contact with a follower roller and, as a result, the oscillating table 14 is oscillated in accordance with the profile of the master cam, to give a creating movement for grinding the cam material W into a required shape to the part between the grinding wheel 3 and the cam material W.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cam grinding method for grinding a cam material into a desired shape by applying profile generating motion and cutting feed between a grinding wheel and a cam material.

Conventionally, in order to grind a cam material, the master cam is brought into contact with the follower roller by the swinging of the oscillator to give the cam material a generating motion, and then the grinding wheel is moved forward toward the cam material to perform the grinding process. However, in this operating process, the grinding wheel is actually involved in grinding only when the grinding wheel advances into the cut, and no grinding is performed when the master cam contacts the follower roller. .

Therefore, when the cam material is cut and moved forward toward the grinding wheel that is moving forward due to the vibration of the shaking table, the follower is brought into contact with the master cam at the same time. No special time is required, and the cam grinding time can be shortened.

On the other hand, when grinding cams, the cam material usually has a speed of 60 to 90 per minute.
When cutting the cam material on the rocking table side as described above, the top part of the cam material is cut many times in a state where the generating mechanism is not yet functioning. Contact with the grinding wheel causes the top part to be locally scraped off, and as a result, the machining allowance after the cam material starts its generating motion becomes uneven, reducing grinding accuracy.Furthermore, while the master cam rotates at high speed, Since it comes into contact with the follower roller, there is a risk of damaging the master cam.

Therefore, the object of the present invention is to cut the cam material by swinging the rocking table against the grinding wheel which has been positioned at the cutting forward end, and then to bring the master cam into contact with the follower roller. The objective is to shorten the cam grinding time.

Furthermore, another object of the present invention is that the cam material is
Set the relative cutting speed of the cam material to the grinding wheel to a value that gives the cutting depth to the rough grinding advance end while rotating,
Therefore, it is possible to prevent a decrease in grinding accuracy due to local grinding of the cam material and to prevent damage to the master cam.

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

In FIG. 1, reference numeral 1 denotes a bed, and a grinding wheel head 2 is slidably placed on this bed 1, and a morph 4
A grinding wheel 3 which is rotationally driven by is rotatably supported. A feed nut 5 is fixed to the bottom surface of the grindstone head 3.
A feed screw 6 is screwed into this. This feed screw 6
is mounted on a shaft on the bed 1, allowing only rotational movement, and its rear end is connected to a drive shaft 9 via a gear train 8.

A pinion 10 is removably fitted to the drive shaft 9 by a clutch mechanism of the circuit, and a cylinder device 1 is fitted to the pinion 1o.
A rack 12 reciprocated by 1 is engaged with the rack 12.

A table 13 is placed on the bed 1 so as to be slidable in a direction perpendicular to the reciprocating direction of the grindstone head 2.
A rocking table 14 is supported on the table 3 so as to be swingable around an axis parallel to the sliding direction of the table 13. This 13 moving platform 1
4, as shown in FIG. 2, a bearing body 34 that rotatably supports the main shaft 33 and a circuit tailstock are arranged facing each other, and the cam material W is connected to the center of the main shaft tip and the tailstock. Sen・
Rotation is transmitted to this main shaft 33 from a ball change motor 19 fixed on a gear box 18 via a belt mechanism 20. (See Fig. 1) Reference numeral 35 denotes a headstock fixed on the table 13, and the headstock 35 includes a support 3 that rotatably supports a master cam 36 fitted on the main shaft 33 and a follower roller 37 facing the main shaft 33.
8 is installed. A tension spring 4o is tensioned between the protruding arm 39 protruding from the side surface of the rocking table 14 and the headstock 35, and this tension spring 40 causes the master cam 36 to contact the follower roller 37 on the rocking table 14. A repellent force is applied in the direction of contact. Reference numeral 46 denotes a cylinder device fixed to the headstock 35. For example, by supplying pressure oil to the upper chamber of this cylinder device 46 and lowering the piston rod 47, the rocking table 32 is rotated counterclockwise and the master cam is rotated counterclockwise. 36 is detached from the follower roller 37, and conversely, pressure oil is supplied to the lower chamber of the cylinder device 46 to raise the piston rod 47, so that the rocking table 14 is rotated clockwise by the repulsive force of the tension spring 40. Then, the cam blank W is cut forward with respect to the grinding wheel 3.

The LSI is a proximity switch that detects one revolution of the cam blank W by corresponding to a dog 47 attached to the main shaft 33.

Next, the operation of the above configuration will be explained while explaining the control circuit shown in FIG.

FIG. 4(A) shows the cam material W being centrally supported by the main shaft 33 and immediately before cam grinding is started. In this state, the grinding wheel 3 is already at the forward cutting end P for rough grinding, and The surface of the cam blank W after being ground by the rough grinding allowance ΔA is at a position retreated by L2 from the rough grinding cutting forward end P.

When the start switch 5TART shown in FIG. 3 is pressed, the flip-flop FF2 is set and a low speed rotation command is given to the pole number conversion circuit 50, causing the motor 19 to rotate at a low speed. As a result, the main shaft 33 and the cam blank W centrally supported by the main shaft 33 are rotated at low speed in the direction of the arrow shown in FIG. 4(A). When a signal is output from the delay circuit DC1 after the rotation of the main shaft 33 has started, the flip-flop F
F1 is set, the solenoid of the switching valve VI is energized, and the switching valve ■1 is switched to the position ■.

As a result, pressure oil is supplied to the lower chamber of the cylinder device 46, and the piston rod 47 is raised. As a result, the rocking table 14 is moved clockwise by the repulsive force of the tension spring 40 (
As shown in FIG. 4(B), the cam blank W is moved forward toward the grinding wheel 3 located at the forward end of the cut, giving the cam blank W a rough grinding cut. The relative feed speed of the cam blank W with respect to the grinding wheel 3, that is, the cutting speed for rough grinding, is controlled by a throttle valve 55 provided in the oil passage, so that the cam blank W rotates once as shown in FIG. The speed is set such that the material W is cut to the forward cutting end for rough grinding. Therefore, the top portion of the cam blank W does not come into contact with the grinding wheel 3 many times during this rough grinding feed and be locally removed.

When the cam blank W has been cut to the forward cutting end PI for rough grinding, the master cam 36 and the follower roller 37 come into contact, and as a result, the rocking table 14 is rocked according to the profile of the master cam 36, and the grinding wheel 3 A generating motion is applied between the cam material W and the cam material W to grind the cam material W into a desired shape. At this time, since the main shaft 33 is being rotated at a very low speed as described above, the master cam 36 smoothly contacts the follower roller 37, and there is no risk of damaging the master cam 36.

After the cam material W has been cut to the forward cutting end P for rough grinding, most of the amount to be removed by rough grinding can be removed by rotating the cam material W at least once while making a generating motion. However, in this embodiment, the cam blank W was rotated twice at low speed after the rough grinding cut was started, allowing for some margin.

That is, at the same time that the flip-flop FFI is set and the cutting advance of the grinding wheel 3 is started, the gate AC;2 is opened, and the Q signal from the approach switch LSI, that is, the number of rotations of the main shaft 33 is counted by the counter 51. . After the cutting of the grinding wheel 3 and the cam material W starts, the main shaft 33 rotates twice, and when the rough grinding is completed, the comparator 52
The flip-flop FF2 is reset by the same signal, and at the same time, the flip-flop FF3 is set. As a result, a high speed rotation command is given to the pole number switching circuit 5o, and the motor 19 rotates the main shaft 33 at a speed of 90 rotations per minute. Then, when the main shaft 33 and the cam blank W rotate three more times and the count value of the counter 51 reaches 5, a signal is output from the comparator 53 and the flip-flop FFI is reset, and as a result, the solenoid of the switching valve Vl becomes inactive. and the switching valve VI is switched to the position (■). As a result, spark-out grinding of the cam blank W is completed, and the cam blank W is retreated rearward.

For grinding the cam material W having a plurality of cam parts, so-called two-step grinding is adopted in which all the cam parts are first roughly ground, and then the metal cam parts are finely ground. This explains the operation of the rough grinding process.When performing rough grinding afterwards, the cam material is moved forward by the rough grinding allowance using the rough grinding feeder of the circuit, rather than causing the cam material to make creative movements. The material W can be easily precisely ground.

As described above, in the cam grinding method of the present invention, the grinding wheel, which has been positioned in advance at the cutting forward end, makes a cut in the material by swinging the rocking table, and at the same time, the master cam is brought into contact with the follower roller. Since the cam grinding method is designed to perform ε, the cam grinding time is shorter than that of conventional cam grinding methods, enabling efficient cam grinding, and the configuration of the control device that moves the grinding wheel back and forth is also simple. .

Further, in the present invention, cam grinding is performed by setting the relative cutting speed of the cam material to the grinding wheel to a value such that the cutting speed is given to the rough grinding forward end during one rotation of the cam element. This prevents local grinding of only the top part of the cam material and prevents damage to the master cam.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of a cam grinder that implements the cam grinding method of the present invention, FIG. 2 is an enlarged cross-sectional view of the headstock shown in FIG. 1, and FIG. 3 is shown in FIG. 1. A control circuit diagram for performing rough grinding of a cam material with a cam grinder, Fig. 4 is an explanatory diagram showing the relationship between the grinding wheel and the cam material in the cam grinding method of the present invention, and Fig. 5 shows the relationship between the grinding wheel and the cam material. FIG. 3 is a diagram showing changes in position and rotational speed of the main shaft. 1... Bed, 2... Grinding wheel, 3... Grinding wheel, 6
...Feed screw, 11...Cylinder device, 14...
Rocking table, 19...Ball change motor, 33...
Main shaft, 36... Master cam, 37... Follower roller, 46... Cylinder device, 50... Pole number switching circuit, 51... Counter, 52.53... Comparator, FF
I, FF2. FF3...Flip-flop circuit, LS
I...Proximity switch, W...Cam material.

Claims (2)

[Claims] (1) A cam blank is rotatably supported on a rocking table, and a master cam provided on the same axis as the cam blank and a follower roller in contact with the master cam give the cam blank a generating motion, and the cam blank In a cam grinding method in which a relative cutting feed is applied between a grinding wheel and a grinding wheel to grind a cam material to a desired dimension, the grinding wheel is stopped at the forward cutting end where a predetermined cutting is made into the cam material, and then the The cam material is ground by the grinding wheel by swinging the shaking table toward the grinding wheel, and then the master cam and the follower roller are brought into contact with each other to start grinding the cam material by copying. Cam grinding method. (2) The cutting speed of the cam blank relative to the grinding wheel due to the swinging of the rocking table is set to a value at which the cam blank is cut to the cutting forward end before the cam blank rotates once, so that the cam blank is roughened. A cam grinding method according to claim 1, characterized in that a grinding process is performed.