JP3260638B2 - Processing method of camshaft based on signal rotor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of processing a camshaft based on a signal rotor when, for example, a signal rotor for a cam position sensor is mounted on the camshaft.

[0002]

2. Description of the Related Art In recent years, an engine adopting a variable valve timing mechanism for the purpose of improving the output and idle stability of an engine by changing a valve timing and a valve lift according to a load state of the engine. Is being developed. In the variable valve timing mechanism, it is necessary to provide a signal rotor for the cam sensor on the camshaft in order to detect the cam position. in this case,
In order to process the signal rotor on the camshaft, dedicated equipment is required for the processing. Also, instead of processing the camshaft, for example,
As disclosed in Japanese Patent Application Publication No. 3 (1993) -3, there is also known an apparatus in which a signal rotor is formed using a camshaft driving pulley.

[0003]

However, when processing the above-described camshaft, a large amount of cost is required to prepare dedicated processing equipment, which increases the manufacturing cost. On the other hand, for example, when a delivery pipe or the like is arranged near the cylinder head, such as a fuel injection system, if a cam sensor is arranged so as not to interfere with the delivery pipe, the cam sensor may be located at a rear end portion of the cam shaft. . By the way, at the rear end of the camshaft, there is provided a reference hole indicating a reference position for processing the camshaft. When the signal rotor of the cam sensor is provided at such a rear end, if the reference hole is deleted or covered, it may not be possible to perform later cam processing or attachment to the cylinder head. Therefore, in order to machine such a camshaft, a dedicated facility is required, which may increase the production cost.

An object of the present invention is to solve such a problem.

[0005]

In order to achieve the above object, the present invention takes the following measures. In other words, the method for processing a camshaft based on the signal rotor according to the present invention cuts the end of the camshaft so that the camshaft can be used also as the one without the signal rotor and the cam processing equipment can be shared. A positioning groove is provided at a predetermined position of the cut end, and a signal rotor having processing reference means is mounted through the positioning groove. Therefore,
Since the cam can be processed based on the processing reference means of the signal rotor, the need for dedicated processing equipment is eliminated, and an increase in cost can be suppressed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is based on a signal rotor in which a signal rotor of a cam sensor is mounted at an end of a camshaft of a multi-cylinder engine, and the camshaft can be machined based on the mounted signal rotor. A camshaft machining method according to claim 1, wherein the end of the camshaft having the machining reference means is cut to a predetermined diameter, and cut based on a type discriminating projection provided on the camshaft with a predetermined inter-journal setting. A positioning groove for the signal rotor is provided at the end, and a signal rotor provided with processing reference means on the surface is press-fitted to be mounted at a predetermined position on the end via the positioning groove. This is a method for processing a camshaft based on a signal rotor.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In a double overhead camshaft (DOHC) engine equipped with a variable valve timing mechanism, a cam sensor 1 shown in FIG. 1 is provided on a rear side of a cylinder head 2 in order to avoid interference with a delivery pipe for supplying fuel to a fuel injection valve. It is to be attached to.
In this embodiment, an intake camshaft 3 and a cam sensor 1 in a three-cylinder engine will be described. The cam sensor 1 includes a signal rotor 11 mounted by press-fitting on a rear end portion 3a which is an end portion of the intake camshaft 3;
An electromagnetic pickup 12 fitted into the cylinder head 2. The cylinder head 2 has a mounting hole 2a at the rear end side for mounting the electromagnetic pickup 12. In FIG. 6, reference numeral 2b denotes a bearing portion of the intake camshaft 3, and 2c denotes a valve hole for an intake valve.

The intake camshaft 3 for press-fitting the signal rotor 11 is also used as an engine without a variable valve timing mechanism. Before machining for the signal rotor 11, as shown in FIGS. The rear end 3a has a flange 3b which is larger than the shaft diameter R. In the rear end face of the flange 3b, a machining reference hole 4 is formed as machining reference means for cam machining of the intake camshaft 3. In addition, a type determining projection 3e for setting a gap between the second journal 3c and the third journal 3d, which is a predetermined journal, is integrally provided on a shaft portion between the second journal 3c and the third journal 3d. is there. The type determining projection 3e is provided so as to form a predetermined angle, for example, 82.42 ° around the axis with the reference machining hole 4.

The signal rotor 11 is an annular flat plate having a signal projection 11a protruding on the outer periphery. In the case of this embodiment, since it is a three-cylinder engine, three are provided at an angle of 120 °. In order to position the signal rotor 11, a key projection 11b that fits into the key groove 5 serving as a positioning groove provided on the intake camshaft 3 is provided on the inner periphery of the signal rotor 11 so as to face the signal projection 11a. I have. Further, a machining reference hole 11c, which is a machining reference means in place of the machining reference hole 4 which disappears by cutting, is formed in an intermediate portion between the key projection 11b and the signal projection 11a. The processing reference hole 11c is provided at a position corresponding to the position of the processing reference hole 4 that has disappeared by cutting when the signal rotor 11 is pressed into the rear end 3a of the intake camshaft 3. In addition, this processing reference hole 11c is
It may be a concave hole which does not penetrate the member.

The rear end of the intake camshaft 3 is formed by first cutting and removing the entire flange 3b, and further cutting the outer diameter of the fuel pump cam 3f in the front end direction, and cutting the rear end. The outer diameter of the portion 3a is made substantially equal to the inner diameter of the signal rotor 11. As a result, a rear end 3aa having a diameter smaller than the outer diameter of the journal portion of the intake camshaft 3 is formed at the rear end 3a. By this cutting, the processing reference hole 4 disappears. Next, the type discrimination projection 3 is attached to the cut rear end 3aa.
The key groove 5 is formed based on e. In the case of this embodiment, since the processing reference hole 11c is provided in the radial direction of the key projection 11b of the signal rotor 11, the key groove 5 is formed at a position away from the type discrimination projection 3e by the predetermined angle.
This position is a position facing the straight line of the position where the machining reference hole 4 was located before cutting.

After the machining of the rear end 3a of the intake camshaft 3 is completed as described above, the key projection 11b of the signal rotor 11 is aligned with the key groove 5, and the signal rotor 11 is connected to the intake camshaft 3. Press in.
When the press-fitting is completed, a machining reference hole 11 provided in the signal rotor 11 is formed in the rear end 3a of the intake camshaft 3.
c appears at the same position as the machining reference hole 4 existing before machining. Therefore, the subsequent cam machining of the intake camshaft 3 is performed with reference to the machining reference hole 11c. As a result, the facility required for cam processing need not be dedicated to the intake camshaft 3 for the variable valve timing mechanism, and processing can be performed at the same facility as the normal intake camshaft 3.

As described above, the intake camshaft 3 can be used both for an engine equipped with a variable valve timing mechanism and for an engine not equipped with a variable valve timing mechanism, and no special facility is required for cam processing. Therefore, the manufacturing cost can be reduced. Further, the rear end 3a is cut into a small diameter by cutting according to the inner peripheral diameter of the signal rotor 11, and the cut rear end 3a is cut.
Since only the key groove 5 is provided in the position a, the processing can be minimized.

The present invention is not limited to the embodiment described above, but may be applied to an exhaust camshaft. In addition, the configuration of each unit is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0014]

As described above, according to the present invention, since a dedicated facility for processing is not required, the camshaft can be processed at low cost. Therefore, the manufacturing cost can be reduced. Further, since the camshaft to which the signal rotor is attached can be processed in the same manner as the camshaft without the signal rotor attached, both can be used as the camshaft, and an increase in manufacturing cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is an enlarged perspective view showing a main part of an embodiment of the present invention.

FIG. 2 is a side view of the intake camshaft of the embodiment.

FIG. 3 is a rear view of the intake camshaft of the embodiment.

FIG. 4 is a side view of a main part showing a shape after processing of a rear end portion of the intake camshaft according to the embodiment.

FIG. 5 is a rear view showing, in a partial cross section, a state in which a processed intake camshaft is set on the cylinder head of the embodiment.

FIG. 6 is a plan view of the cylinder head of the embodiment, with a part thereof omitted;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cam sensor 3 ... Intake camshaft 3a ... Rear end 3e ... Type discrimination protrusion 4 ... Processing reference hole 5 ... Key groove 11 ... Signal rotor 11c ... Processing reference hole

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B23B 5/18 B23P 21/00 303 F01L 1/04

Claims (1)

(57) [Claims] A camshaft is mounted on an end of a camshaft of a multi-cylinder engine, and a signal rotor of a cam sensor is mounted, and the camshaft is processed based on the mounted signal rotor. A method comprising: cutting an end of a camshaft having a machining reference means to a predetermined diameter; and providing a signal to said end cut based on a type discriminating projection provided on a camshaft with a predetermined inter-journal setting. A camshaft based on a signal rotor, wherein a positioning groove for the rotor is provided, and a signal rotor provided with processing reference means is press-fitted to be mounted at a predetermined position on the end portion via the positioning groove. Processing method.