JPH08121206A - Rotational position detection device for internal combustion engine - Google Patents

Abstract

PURPOSE: To downsize a reduce, and facilitate mounting operation by arranging a magnet pick up in a space surrounded by means of a circular body, and on a front surface of a cylinder head, thereby effectively utilizing a dead space. CONSTITUTION: A signal rotor 4 is rotatably arranged inside a cylinder head 1, and integrated with a back surface of a rotational body mounted on a cam shaft 2 for reciprocating a valve body. A magnet pick up 5 is provided for outputting electric signal according to magnetic flux which is fluctuated when teeth formed on an outer periphery of the signal rotor 4 passes. The magnet pick up 5 is arranged in a space formed while being surrounded by a circular body laid between the crank shaft and a cam pulley 3 at a front surface of the cylinder head 1, in the vicinity of the signal rotor 4. A device can thus be downsized. Unnatural stance of an operator is prevented at the time of mounting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational position detecting device mainly installed in an internal combustion engine for automobiles.

[0002]

2. Description of the Related Art Conventionally, this main rotational position detecting device has a signal rotor attached to a timing pulley attached to one end of the camshaft so as to rotate the camshaft in the cylinder head in response to the rotation of the crankshaft. It is known that a magnet pickup that is integrally mounted and that causes a change in magnetic flux due to passage of a signal rotor is fixed at a position close to the signal rotor so that the entire apparatus becomes compact (for example, an actual Kaihei 3-61503).

[0003]

By the way, in the case where the signal rotor is integrally attached to the timing pulley as described above, the magnet pickup is arranged so that noise due to the influence of the signal rotor is not superimposed on the output waveform of the magnet pickup. It is necessary to move the position of (1) to a position where the magnetic field is not affected by the timing pulley. That is, it is necessary to make the outer diameter of the signal rotor larger than the outer diameter of the timing pulley, or to make the outer diameter of the timing pulley smaller.

However, for example, if the outer diameter of the signal rotor is made large so as not to generate noise,
In the case of a double overhead camshaft (hereinafter referred to as DOHC), it becomes difficult to mount the signal rotor within the camshaft pitch range. In addition, if the signal rotor is made larger, it is necessary to make the structure of the mounting position of the timing pulley such as the head cover larger, which may increase the outer shape of the internal combustion engine.

On the other hand, when the timing pulley has a small diameter,
Although there is a possibility of shortening the life of the stretched timing belt, it is not always preferable in consideration of durability although it enables miniaturization.

[0006] In view of the above situation, the signal rotor is configured to have a tooth for cylinder discrimination and a tooth for top dead center discrimination, and is housed in one housing together with a magnet pickup to form a sensor assembly. It is known that the sensor assembly is formed and connected to the cam shaft through a joint. Since such a sensor assembly is regarded as one functional component when mounted on an internal combustion engine, it has the advantage of being guaranteed as a single sensor in terms of accuracy, but the number of components is large when assembled, and The manufacturing cost tended to increase from the point that they had to be linked together.

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

[0008]

The respective inventions of the present application take the following means in order to achieve such an object. That is, the rotational position detecting device for an internal combustion engine of the invention according to claim 1 of the present application is integrally provided on the back surface of the rotating body that is rotatably provided in the cylinder head and is attached to the cam shaft that reciprocates the valve body. A signal rotor and a magnet pickup that outputs an electric signal according to the magnetic flux that changes when the teeth provided on the outer peripheral portion of the signal rotor pass,
The magnet pickup is on the front of the cylinder head,
The signal rotor is mounted close to the signal rotor in a space surrounded by an annular body stretched between the crankshaft and the rotating body.

Further, the rotational position detecting device for an internal combustion engine according to a second aspect of the present invention is integrally formed on the back surface of the rotating body mounted on the cam shaft rotatably provided in the cylinder head for reciprocating the valve body. And a magnetic pickup that outputs an electric signal according to the magnetic flux that changes when the teeth provided on the outer peripheral portion of the signal rotor pass, and the teeth of the signal rotor are It is characterized in that it is provided so as to project in the centrifugal direction in a parallel state separated from the rotating body in the axial direction.

Further, in the rotation detecting device for an internal combustion engine of the invention according to claim 3 of the present application, it is integrally provided on the back surface of the rotating body attached to the cam shaft rotatably provided in the cylinder head for reciprocating the valve body. The signal rotor is provided with a magnet pickup that outputs an electric signal according to the magnetic flux that changes when the teeth provided on the outer peripheral portion of the signal rotor pass, and the signal rotor has the number of cylinders of the internal combustion engine. 1 is added to the teeth, and the teeth are provided so as to project in the centrifugal direction in a parallel state in which the teeth are separated from the rotating body in the axial direction of the cylinder head.

[0011]

With the structure of the invention according to claim 1 of the present application, the dead space can be effectively utilized by mounting the magnet pickup in the space surrounded by the annular body. Therefore, the device can be downsized. Further, since the magnet pickup is mounted on the front surface of the cylinder head, the mounting work is facilitated, and in addition, the position adjustment work for the signal rotor is facilitated.

With the structure of the invention according to claim 2 of the present application, the teeth protruding to the outer periphery of the signal rotor are
Between the back of the rotating body and the front of the cylinder head, which becomes a dead space when attaching the rotating body to the camshaft,
It can be arranged in a state of being separated from the rotating body. Therefore, the rotating body can be moved away from the magnet pickup, and the influence of the rotating body on the output signal of the magnet pickup can be suppressed.

Further, with the structure of the invention according to claim 3 of the present application, it is possible to make the outer diameter of the signal rotor large so as to approximate the outer diameter of the rotating body. Therefore, even in the signal rotor in which the teeth for detecting the top dead center are added to the teeth for determining the cylinders corresponding to the number of cylinders of the internal combustion engine, the output signals corresponding to the respective teeth are clearly detected and detected. It becomes possible to do. Moreover, since the signal rotor is integrally provided on the back surface of the rotating body,
The dead space can be effectively used, the structure can be simplified, and the manufacturing cost can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The rotational position detecting device shown in FIG.
Which is mounted on a three-cylinder four-cycle engine of a rotary type and is integrally mounted on a rear surface 3a of a cam pulley 3 which is a rotating body which is rotatably provided in a cylinder head 1 and which is attached to a cam shaft 2 which reciprocally operates a valve which is not shown And a magnet pickup 5 that outputs an electric signal according to the magnetic flux that changes when the teeth 4a provided on the outer peripheral portion of the signal rotor 4 pass.

The cam pulley 3 has a bolt 6 concentrically with the camshaft 2 at the front end of the exhaust-side camshaft 2 whose end projects from the front end of the cylinder head 1 to the outside.
It is fixed by. The cam pulley 3 may be basically the same as one widely known in this field,
The signal rotor 4 can be positioned on the back surface 3a and fixed by bolts 7. That is, the cam pulley 3 has a strip-shaped ring body 3c having a width larger than the thickness of the disc 3b on the outer peripheral portion of the disc 3b so that its surface is perpendicular to the disc 3b. And a ring body 3c are integrally formed. Ring body 3
The c has teeth on its outer peripheral surface that mesh with the timing belt 8. Note that the teeth of the ring body 3c are not shown together with the teeth of the timing belt 8 in order to prevent complication. 3d is a positioning hole,
A positioning pin 2a for determining the position when the cam pulley 3 is attached to the cam shaft 2 is fitted. The positioning pin 2a is planted on the end surface of the camshaft 2.

The signal rotor 4 has a main body portion 4b having a smaller diameter than the cam pulley 3, and tips of teeth 4a integrally formed on the outer peripheral portion of the main body portion 4b are located outside the cam pulley 3. That is, the main body portion 4b has a shape in which the periphery of the disc is bent vertically, and the vertical wall portion 4c thereof is formed.
The outer diameter of is completely accommodated inside the ring body 3c on the back surface 3a of the cam pulley 3. A mounting hole 4d that fits into the boss 3e on the back surface 3a of the cam pulley 3 is provided at the center of the disc portion of the body portion 4b. In addition, the disk portion of the main body portion 4b is provided with a through hole into which a bolt hole 9 for inserting the fixing bolt 7 and a positioning pin 10 are inserted. The height of the vertical wall portion 4c in the main body portion 4b is such that the ring body 3c protruding toward the back surface 3a side.
Is about twice as wide as the width of the ring body 3c, that is, about 1/2 of the height of the ring body 3c is projected from the rear side edge of the ring body 3c so that the teeth 4a are sufficiently separated from the cam pulley 3. Tooth 4
3a is provided with three teeth 4am for cylinder discrimination, which are separated by 240 ° from the center, and one tooth 4an for detecting the top dead center is provided at a predetermined position, corresponding to the number of cylinders. To be These teeth 4a are formed on the outer side in the vertical direction with respect to the vertical wall portion 4c, in other words, protruding in the centrifugal direction of the signal rotor 4 in a parallel state separated from the cam pulley 3 in the axial direction of the cylinder head 1.

The magnet pickup 5 is on the front surface of the cylinder head 1 and on a crankshaft (not shown).
The signal rotor 4 is mounted in the space S surrounded by the timing belt 8 which is an annular body stretched between the signal rotor 4 and the cam pulley 3. This magnet pickup 5 has an L shape when viewed from the side,
A coil portion 5a containing a pickup coil extends vertically upward from the base portion 5b. Foundation part 5b
Has a substantially cylindrical shape, a positioning pin 5c is integrally formed at the end on the coil portion 5a side, and a wiring connector portion 5d is formed at the other end.
The connector portion 5d is adapted to project outward from the recess 11a of the timing belt cover 11 when the magnet pickup 5 is attached to the cylinder head 1 and the timing belt cover 11 is attached. Further, when the base portion 5b is viewed from the front, the mounting arm 5e extends laterally.
The magnet pickup 5 can be fixed by inserting a bolt 12 into a bolt hole (not shown) provided in e and screwing it into the cylinder head 1.

In such a structure, first, the signal rotor 4 is fixed to the back surface 3a of the cam pulley 3 with the bolt 7. In this case, the cam pulley 3 and the signal rotor 4 can be quickly aligned with the positioning pin 10. The cam pulley 3 to which the signal rotor 4 is integrally attached is provided with a positioning pin 2 for the cam shaft 2.
A is inserted into the positioning hole 3d for positioning, and the bolt 6 is tightened to be fixed to the camshaft 2. In this state, the signal rotor 4 is located in the dead space Sd between the back surface 3a of the cam pulley 3 and the front surface of the cylinder head 1, as shown in FIG. That is, the main body portion 4 b and the teeth 4 a of the signal rotor 4 are connected to the end portion of the cam shaft 2 to which the cam pulley 3 is attached and the cylinder head 1.
The bearing portion 1a is enclosed in a dead space Sd formed between the rear side of the cam pulley 3 and the front surface of the cylinder head 1.

Therefore, the mounting position of the cam pulley 3 does not move in the front direction of the cylinder head 1 by mounting it on the cam pulley 3, and the same position as in the conventional case can be secured. Further, the substantial outer diameter of the signal rotor 4, in other words, its main body portion 4b excluding the tooth 4a portion
Since the outer diameter of is smaller than that of the cam pulley 3, it can be accommodated within the camshaft pitch P. As a result,
The included angle of the camshaft 2 can be reduced, and the engine performance is not adversely affected. On the other hand, tooth 4
Since the outer diameter of a is slightly larger than the outer diameter of the cam pulley 3, the overall size can be reduced, and the accuracy of the output signal is in addition to the teeth 4am for cylinder discrimination, and the accuracy of the output signal is for detecting the top dead center. Even though the tooth 4an is provided, it can be held with high accuracy.

Next, the magnet pickup 5 is attached so as to correspond to the signal rotor 4. That is, in the magnet pickup 5, the positioning pin 5c formed at the front end is inserted into the mounting hole of the cylinder head 1, and the mounting arm 5e is fixed to the front surface of the cylinder head 1 with the bolt 12. This magnet pickup 5
The mounting position of is a space S surrounded by the timing belt 8 on the front surface of the cylinder head 1 when viewed from the front, and is a dead space as in the case of the signal rotor 4. Further, at this mounting position, there is no obstacle on the front side until the timing belt cover 11 is mounted, and it is possible to work from the front of the cylinder head 1, which facilitates the mounting work. Moreover, since the magnet pickup 5 has a shape in which the mounting arm 5e extends to the side of the base portion 5b, positioning is easy and the mounting work can be shortened. In addition, the connector portion 5d of the magnet pickup 5 is provided with the timing belt cover 1 when the timing belt cover 11 is attached.
Since it protrudes to the outside of 1, the electric connection work between the magnet pickup 5 and the outside can be easily performed without removing the timing belt cover 11, and wiring for electric connection from the timing belt cover 11 due to vibration or the like. It is possible to prevent partial damage at the drawing position of or in the vicinity thereof.

Further, looking at the positional relationship among the signal rotor 4, the magnet pickup 5, and the cam pulley 3 attached in this way, the teeth 4a of the signal rotor 4 have the teeth 4a in the axial direction of the cam shaft 2 and the cam pulley 3.
Since it is separated from the trailing edge surface of the cam pulley 3, the trailing edge surface of the cam pulley 3 does not enter into the magnetic field Mf (indicated by the dotted line hatching in FIG. 1) Mf for signal detection of the magnet pickup 5. Therefore, the magnetic pickup 5
Noise is not superimposed on the output signal output from
Cylinder discrimination and top dead center detection are facilitated, and the configuration of the signal processing circuit therefor can be simplified.

The invention of the present application is not limited to the embodiments described above. For example, the rotating body may be a timing sprocket in addition to the cam pulley 3. In this case, a timing chain is used as the annular body.

The signal rotor 4 is caulked,
It may be integrally provided on the back surface of the cam pulley. Alternatively, the signal rotor 4 may be integrally formed on the back surface of the cam pulley by sintering, casting, or the like. Further, in the above embodiment, the teeth 4 of the signal rotor 4 are
Although a has been described as a in which 1 is added to the number of cylinders, one tooth for detecting the top dead center may be formed.

In addition, the configuration of each part is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0026]

As described in detail above, the invention according to claim 1 of the present application uses a space surrounded by an annular body and having a substantially low utility value, that is, a so-called dead space. The device can be downsized. Further, since the space is formed in the front surface of the cylinder head, the mounting work and the position adjustment work for the signal rotor can be performed from the front of the cylinder head, and the work in an unreasonable posture is prevented. it can.

Further, in the invention according to claim 2 of the present application, the signal rotor is attached to the back surface of the rotating body, and the teeth of the signal rotor are provided between the back surface of the rotating body and the front surface of the cylinder head from the rotating body. Since the magnetic pickups are located apart from each other, the magnetic pickup can generate an original signal due to the passage of the teeth without being affected by the rotating body.

Further, in the invention according to claim 3 of the present application, as described above in detail, the outer diameter of the signal rotor can be made large so as to be close to the outer diameter of the rotating body.
Even if the number of teeth is the number of cylinders plus one, the output signals corresponding to the respective teeth can be clearly distinguished and detected. Moreover, since the signal rotor is integrally provided on the back surface of the rotating body, the unusable space can be effectively used, and the structure can be simplified and the manufacturing cost can be kept low.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a front view showing an enlarged main part of the embodiment.

FIG. 3 is a plan view showing an enlarged main part of the embodiment.

FIG. 4 is a rear view of the cam pulley to which the signal rotor of the embodiment is attached.

[Explanation of symbols]

 1 ... Cylinder head 2 ... Cam shaft 3 ... Cam pulley 3a ... Rear surface 4 ... Signal rotor 4a ... Tooth 5 ... Magnet pickup 8 ... Timing belt

Claims (3)

[Claims] 1. A signal rotor integrally provided on a back surface of a rotating body mounted on a cam shaft rotatably provided in a cylinder head for reciprocating a valve body, and teeth provided on an outer peripheral portion of the signal rotor. It comprises a magnetic pickup that outputs an electric signal according to the magnetic flux that changes when it passes, and the magnetic pickup is in front of the cylinder head.
A rotary position detecting device for an internal combustion engine, which is mounted close to a signal rotor in a space formed by being surrounded by an annular body stretched between a crankshaft and a rotating body. 2. A signal rotor integrally provided on a back surface of a rotating body mounted on a cam shaft rotatably provided in a cylinder head for reciprocating a valve body, and teeth provided on an outer peripheral portion of the signal rotor. It is equipped with a magnet pickup that outputs an electric signal according to the magnetic flux that changes when it passes, and the teeth of the signal rotor are provided so as to project in the centrifugal direction in a parallel state separated from the rotating body in the axial direction of the cylinder head. A rotational position detecting device for an internal combustion engine, comprising: 3. A signal rotor integrally provided on a back surface of a rotating body mounted on a cam shaft rotatably provided in a cylinder head for reciprocating a valve body, and teeth provided on an outer peripheral portion of the signal rotor. And a magnetic pickup that outputs an electric signal according to the magnetic flux that changes when passing through, and the signal rotor has a number of teeth obtained by adding 1 to the number of cylinders of the internal combustion engine. Is provided so as to project in the centrifugal direction in a parallel state in which it is spaced apart from the rotating body in the axial direction of the cylinder head, and the rotational position detecting apparatus for an internal combustion engine.