JPS6250268B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cam piece grinding method for a camshaft, which sequentially grinds a plurality of cam pieces provided in a valve train camshaft of an engine or other camshafts.

The applicant of the present application previously proposed a method of starting grinding from the base circular portion of the cam piece as an efficient method for grinding the cam piece. In order to apply this method to the grinding of the cam pieces of the camshaft, an instruction means is provided for instructing the rotational phase of the camshaft corresponding to the grinding start position of each cam piece provided in the camshaft according to the grinding order, and the instruction means The camshaft is stopped and ready at the specified rotational phase,
It has also been considered that each cam piece starts grinding from a predetermined grinding start position, that is, from the base circle, but in this case, there is a phase difference between the cam piece that has completed grinding and the cam piece that will be ground next. In some cases, it may be necessary to rotate the camshaft more than 180 degrees to a predetermined standby phase indicated by the indicating means after grinding is completed, which can be a major problem in improving productivity. I was getting used to it.

The present invention has been proposed in view of the above problems, and includes sequentially grinding a plurality of cam pieces provided on a camshaft, and changing the rotational phase of the camshaft corresponding to the grinding start position of each cam piece in accordance with the grinding order. An instructing means is provided to instruct the cam shaft to stop and wait at a rotational phase instructed by the instructing means prior to grinding each of the cam pieces, so that each of the cam pieces starts grinding from a predetermined grinding start position. In the apparatus, a discriminating means is provided for discriminating whether the shortest direction between the rotational phase of the camshaft and the rotational phase indicated by the indicating means is forward or reverse, and the camshaft is controlled by the indicating means. A method for grinding a cam piece of a camshaft, characterized in that when the cam piece is rotated to a designated rotational phase, the cam piece is rotated in a direction determined by the determining means.

Next, one example of implementing the present invention will be explained with reference to attached drawings.

In the drawing, reference numeral 1 denotes a known rocking cradle equipped with a centering shaft 2 at one end and a workpiece rotation shaft 3 at the other end, and between the two shafts 2 and 3, a plurality of cam pieces 4, which are workpieces, are arranged.
The camshaft 5 equipped with
is moved to a grinding position facing the circumferential surface of one of the cam pieces 4, and then the cradle 1 is swung toward the grinding wheel 6. Grinding is performed, and after completion of grinding to a predetermined depth at the grinding start position, the camshaft 5 is rotated by the work rotation shaft 3, and the cam piece 4 is ground over the entire circumference while the cradle 1 is oscillated by a master cam (not shown). After grinding is completed, move the grindstone 6,
The above operations are repeated to sequentially grind each cam piece 4.

In the drawings, reference numeral 7 indicates an instruction means for instructing the rotational phase of the camshaft 5 corresponding to the grinding start position of each cam piece 4 in the base circular portion 4a according to the grinding order. The means 7 uses a signal from a limit switch 9, which moves in conjunction with the movement of the rotary grindstone 6, on a cam plate 8 having irregularities corresponding to the arrangement of the cam pieces 4 to determine the number from one end of the cam piece 4 to be cut next. Counter 10 for detecting something
and a storage device 11 for reading out the rotational phase of the camshaft 5 that corresponds to the signal from the counter 10 among the rotational phases of the camshaft 5 stored in advance for each cam piece 4. The instruction signal and the signal from the rotational phase detector 12 of the camshaft 5 interlocked with the work rotation shaft 3 are input to the control circuit 14 of the drive motor 13 of the work rotation shaft 3, and the camshaft 5 is operated according to the instruction signal. The rotation phase is rotated to a predetermined rotation phase and stopped at the rotation phase.

Although the above is not particularly different from what was described above, according to the present invention, the direction of the shortcut between the rotational phase of the camshaft 5 and the rotational phase indicated by the indicating means 7 is forward or reverse. A discriminating means 15 for discriminating is provided, and when the camshaft 5 is rotated to the rotational phase indicated by the indicating means 7 as described above, the camshaft 5 is rotated in the direction determined by the discriminating means 15.

That is, as shown in FIG. 2, when the angular difference between the rotational phase a of the camshaft 5 and the rotational phase b indicated by the indicating means 7 is α in the forward direction and β in the reverse direction, α<β. The servo control circuit 1 determines whether α>β, and outputs a forward rotation signal in the former case and a reverse rotation signal in the latter case.
4, and the camshaft 5 is rotated to a designated predetermined rotational phase, that is, a phase in which the base circular portion 4a of the cam piece 4 to be ground next is opposed to the rotary grindstone 6, and cutting is started from the base circular portion 4a. The rotation was made to take a shortcut.

What is shown in FIGS. 3 and 4 is a bail circular portion 4 which is a cutting start position of each cam piece 4 with an axial gap on a shaft 16 that is interlocked with the work rotation shaft 3.
A protrusion 17 is formed at a position in the circumferential direction corresponding to a, and this constitutes the indicating means 7, and is a cam that moves axially on the shaft 16 in conjunction with the movement of the rotary grindstone 6 and performs the next grinding. The first limit switch 18 is set at the axial position where the protrusion 17 corresponding to the cam piece 4 is formed, so that when the camshaft 5 rotates prior to grinding the cam piece 4, when the switch 18 comes into contact with the protrusion 17, the rotation is stopped. Further, a discrimination groove 19 is formed in the shaft 16 adjacent to each projection 17 in the axial direction and extends over half the circumference of the shaft 16, and a second limit switch is provided in parallel with this and the first limit switch 18. 20 constitutes a discriminating means 15, and the second limit switch 20 is connected to the discriminating groove 1.
If the camshaft 5 exists in the rotational phase inserted into the shaft 9, the camshaft 5 is given normal rotation, and otherwise it is given reverse rotation.

As described above, according to the present invention, when the camshaft is rotated to a predetermined rotation phase instructed by the instruction means prior to grinding each cam piece so that each cam piece starts cutting from a predetermined grinding start position, The determining means determines whether the direction of a shortcut to the predetermined rotational phase is forward or reverse, and the camshaft is rotated in the determined direction, so that the camshaft is always rotated in the shortest direction. This has the effect of shortening time and improving productivity.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an example of the device used to carry out the present invention, Fig. 2 is a diagram explaining its operation, and Fig. 3 is a diagram illustrating its operation.
The figure is a perspective view of a modified example of the apparatus used for carrying out the present invention, and FIG. 4 is a cutaway sectional view of the main part thereof. 4...Cam piece, 5...Camshaft, 7...Instruction means, 15...Discrimination means.

Claims (1)

[Claims] 1. A plurality of cam pieces provided in a camshaft are sequentially ground, and prior to grinding each cam piece, an instruction means is provided for instructing the rotational phase of the camshaft corresponding to the grinding start position of each cam piece in accordance with the grinding order. The camshaft is stopped at a rotational phase indicated by the indicating means, and the cam pieces start grinding from a predetermined grinding start position, wherein the rotational phase of the camshaft and the rotational phase indicated by the indicating means are controlled. A discriminating means is provided for discriminating whether the direction of the shortcut between the rotational phase indicated by the indicating means is forward or reverse, and when the camshaft is rotated to the rotational phase indicated by the indicating means, the direction determined by the discriminating means is A method for grinding a cam piece of a camshaft, characterized in that the cam piece is rotated in a direction.