JPH0544523A - Starter with built-in rotation sensor - Google Patents

Abstract

PURPOSE:To provide a high precision rotation sensor by means of eliminating processing of an engine block and making it hard to be influenced by leakage flux from a starter coil by making a structure to integrally install the magnetic rotation sensor on a starter. CONSTITUTION:As a rotation sensor 30 is constituted to be integrally installed on the end face 8 of an installation bracket of a starter 1, the rotation sensor 30 is installed simultaneously when the starter 1 is installed on an engine. Accordingly, processing of an engine block is eliminated, and a manday to install the rotation sensor 30 on the engine block is eliminated. Additionally, as a first and a second rotation detection means 33, 35 are constituted to form a magnetic closed circuit, it is possible to increase flux change as a signal even when there is leakage flux from outside and to increase an S/N ratio. Accordingly, it is possible to detect engine rotation in favourable precision.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation sensor for detecting the rotation of an automobile engine, and more particularly to a rotation sensor built-in starter in which a magnetic rotation sensor is integrally attached to a main body of a starter for starting the engine.

[0002]

2. Description of the Related Art A conventional magnetic rotation sensor for an automobile engine has a sensor main body arranged facing a tooth portion of a rotary plate, as described in, for example, Japanese Patent Laid-Open No. 1-321368.
The sensor body consists of a permanent magnet, a core member (iron core) magnetically connected to the permanent magnet, the tip of which is arranged in the vicinity of the teeth of the rotary plate, and a detection coil wound around the core member. I am configuring. In this case, the sensor body is usually fixed to the engine block. Further, the permanent magnet and the core member of the sensor body, and the teeth of the rotating plate and the rotating plate facing the tip of the core member form a magnetic open circuit.

Further, as a structure in which a rotation sensor is attached to a starter, there are those disclosed in Japanese Utility Model Publication No. 57-15978 and Japanese Utility Model Publication No. 60-156458. The rotation sensor disclosed in Japanese Utility Model Laid-Open No. 57-15978 is not for detecting the rotation of the engine, but for detecting the rotation of the pinion and the rotation of the ring gear, respectively, to detect the meshing state of both. is there. Further, no specific reference is made to how to attach the rotation sensor. On the other hand, Shokai 6
The rotation sensor described in Japanese Patent Laid-Open No. 0-156458 detects the rotation of the engine, but is not an electromagnetic type, but includes a projector that emits electromagnetic waves or ultrasonic waves and a receiver that receives the electromagnetic waves or ultrasonic waves. Is adopted.

[0004]

As described above, in the conventional magnetic rotation sensor for an automobile engine, the sensor body is usually fixed to the engine block. Therefore, the engine block is mounted for mounting the sensor body. Need to be processed, and a device to prevent oil leakage is required. In addition, the number of steps required to attach the sensor body to the engine block is required, and adjustment after attachment is also required. Furthermore, since the conventional magnetic rotation sensor forms a magnetic closed circuit, when the starter is started, it is easily affected by the leakage magnetic flux from the starter coil, and there is a problem that the rotation sensor may erroneously detect. It was

Further, since the rotation sensor described in Japanese Utility Model Laid-Open No. 60-156458 is a method of transmitting and receiving electromagnetic waves or ultrasonic waves, there is a problem that the installation position of the projector and the receiver is restricted and it is not practical. there were.

An object of the present invention is to provide a magnetic rotation sensor integrally attached to a starter, which eliminates the need for machining an engine block and is less susceptible to magnetic flux leakage from the starter coil. It is to provide a starter with a built-in rotation sensor.

[0007]

In order to achieve the above object, a starter with a rotation sensor according to the present invention includes a starter for starting an engine by rotating a ring gear directly connected to an output shaft of an automobile engine, and a starter. And an electromagnetic rotation sensor for detecting rotation of the engine, wherein the electromagnetic rotation sensor is formed so as to face different tooth portions of the ring gear at predetermined air gaps. First pole piece, a first iron core magnetically connected to the first pole piece, a permanent magnet interposed between the first iron core and the second pole piece, and a first core wound around the iron core. And a first rotation detecting means composed of a detection coil, and first and second pole pieces, a first iron core and a permanent magnet, and tooth portions of a ring gear facing the first and second pole pieces. as well as In the ring gear is obtained by the structure forming a magnetic closed circuit.

[0008] Preferably, the electromagnetic rotation sensor faces the second pole piece and the permanent magnet, the magnetic projection protruding on the outer peripheral side of the ring gear, and the magnetic projection with a predetermined air gap. A third pole piece formed as described above, a second iron core interposed between the third pole piece and the permanent magnet, and a second detection coil wound around the second iron core. A second rotation detecting means,
The third pole piece, the second iron core and the permanent magnet, the magnetic projections facing the third and second pole pieces, the tooth portion of the ring gear, and the ring gear form a magnetic closed circuit.

Also, preferably, the first and second pole pieces and the third pole piece are formed so as to face the tooth portion of the ring gear and the magnetic projection piece with an air gap in the radial direction. ..

Further, preferably, the electromagnetic rotation sensor further comprises a curved yoke for magnetically connecting the first and second iron cores and the permanent magnet, and the electromagnetic rotation sensor has the curved yoke meshing with the ring gear. It is attached to the end face of the starter so as to surround the pinion.

[0011]

[Function] Since the mounting position of the starter and the positional relationship of the ring gear are predetermined by integrally mounting the electromagnetic rotation sensor on the starter, if the electromagnetic rotation sensor is mounted on the starter at an appropriate position, the starter The rotation sensor can be attached at the same time as the engine is attached to the engine. Therefore, the processing of the engine block becomes unnecessary, and the labor for attaching the rotation sensor to the engine block becomes unnecessary.

Further, the first rotation detecting means of the electromagnetic rotation sensor is constituted by the teeth of the ring gear facing the first and second pole pieces, the first iron core and the permanent magnet, and the first and second pole pieces. By forming the magnetic closed circuit by the part and its ring gear, even if there is a leakage magnetic flux from the outside, the magnetic flux change as a signal can be increased and the S / N ratio can be increased. Therefore, it is possible to accurately detect the engine speed. The second rotation detecting means includes a second and a third pole piece, a second iron core and a permanent magnet, a tooth portion of the ring gear facing the second and the third pole piece, a magnetic projection piece and the ring gear. The same applies to the case where a closed circuit is formed.

Also, the first and second rotation detecting means are provided.
The crank angle can be detected by facing the different pole pieces of the ring gear to different tooth portions of the ring gear, and the third and second pole pieces of the second rotation detecting means can be used as the tooth portion of the ring gear and the magnetic projection piece. The top dead center can be detected by facing each other, and the crank angle from the top dead center can be detected by using both together.

Further, the ring gear has a variation in dimension in the axial direction, and while the side surface of the ring gear has a relatively large runout when rotating, the variation in dimension in the radial direction is small and there is little runout in the radial direction. .. Therefore, when the first and second pole pieces and the third pole piece are faced to the tooth portion of the ring gear and the magnetic protrusion with an air gap in the axial direction, it is necessary to increase the gap size. As a result, the change in magnetic flux cannot be increased, but by facing the air gap in the radial direction, the size of the gap can be reduced and the change in magnetic flux can be increased. That is S /
The N ratio can be increased.

The first and second iron cores and the permanent magnets are magnetically connected to each other through the curved yoke, and the electromagnetic rotation sensor is attached to the starter end face so that the curved yoke surrounds the starter pinion. The electromagnetic rotation sensor can be easily attached to the starter by effectively utilizing the small space left between the ring gear and the ring gear.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, the starter 1 includes a motor 2, a magnet switch 3, a reduction unit 4 for increasing the torque of the motor 2, a pinion 5, a pinion 5 and a ring gear 9.
It is composed of a pinion biting mechanism portion 6 that is bitten into.
When power is supplied from the (+) terminal 7, the motor 2 is energized via the magnet switch 3 and a current flows through the mounting bracket 8 to the (-) side power supply (chassis). The rotation of the motor 2 rotates the pinion 5, and the pinion 5 meshes with the ring gear 9 to rotate the ring gear 9. The engine is started by the rotation of the ring gear 9.

As shown in FIG. 2, the mounting bracket 8 of the starter 1 has a mounting flange 8b having a bolt hole 8a.
, A spigot fitting portion 8c, and an end surface 8d, the spigot fitting portion 8c is inserted into a corresponding fitting portion of an engine block (not shown), and bolts are fixed through the bolt holes 8a to fix the starter. 1 is attached to the engine block. The end surface 8d has a circular ring shape surrounding the pinion 5, and a resin case 31 of the magnetic rotation sensor 30 having a ring shape is fixed to the end surface 8d with a screw 32.

The rotation sensor 30 corresponds to a first rotation detector 33 which outputs a signal corresponding to the tooth portion of the ring gear 9 and a magnetic protrusion 34 which is projected on one tooth side surface of the ring gear 9. It is configured in combination with the second rotation detector 35 that outputs a signal.

The signals output from the first and second rotation detectors 33 and 35 are input to the input / output circuit (I / O) 13a of the engine control unit 13, as shown in FIG. Further, sensors 14 for detecting the engine intake air amount, engine temperature, etc. are provided, and signals from these sensors 14 are similarly input to the input / output circuit (I / O) 13a of the engine control unit 13.

When the power source of the battery 15 is connected to each electric component by the key switch 16, the engine control unit 13 inputs the input signal from the input / output circuit (I / O) 13a to the microcomputer (CPU) 13b. After that, the injection coil 20 of the fuel injection valve 17 is energized to inject fuel. Furthermore, the current of the primary coil of the ignition coil 18 is cut off, and a spark is generated in the ignition plug 19,
Perform the engine stroke.

FIG. 5 is a flow chart showing the outline of the processing contents of the microcomputer (CPU) 13b. Step 10
After detecting the air flow rate and the engine rotation as described above at 1 and 102, the fuel injection amount by the fuel injection valve 17 is calculated at step 103. This calculation is performed by calculating the end timing of fuel injection with the crank angle from the top dead center (TDC). Next, in step 104, the energization time of the injection coil 20 is determined, and the procedure 1
The injection coil 20 is energized so that the fuel injection ends at the crank angle calculated in 03. Also, in step 105, the ignition timing is calculated. This calculation is also calculated by the crank angle from the top dead center. Then, in step 106, the current of the primary coil of the ignition coil 18 is cut off so that ignition is performed at the crank angle.

As described above, both the fuel injection end timing and the ignition timing are controlled by the crank angle from the top dead center.
Therefore, in the engine rotation detection of step 102, the engine rotation is detected as the crank angle from the top dead center based on the signal from the first rotation detector 33 and the signal from the second rotation detector 35. That is, the crank angle at the tooth portion detection signal of the ring gear 9 of the first rotation detecting unit 33, the top dead center is obtained by the detection signal of the magnetic projection piece 34 of the second rotation detector 35.

Next, the details of the first and second rotation detectors 33 and 35 will be described with reference to FIGS. 6 and 7.

In FIG. 6, the first rotation detector 33 is
The first and second pole pieces 41, 42 formed so as to face the different tooth portions 9a, 9b of the ring gear 9 at predetermined radial air gaps 40a, 40b, respectively, and the first pole piece 41 are magnetically coupled. A first iron core 43 that is electrically connected, a permanent magnet 44 that is magnetically connected to the second pole piece 42, and a yoke 45 that magnetically connects the first iron core 43 and the permanent magnet 44. A first detection coil 46 wound around a bobbin 46a on the first iron core 43, and the first pole piece 41, the first iron core 43, the yoke 45,
The permanent magnet 44, the second pole piece 42, the tooth portion 9b of the ring gear facing the second pole piece 42, the ring gear 9, and the tooth portion 9a of the ring gear facing the first pole piece 41 form a magnetic closed circuit. Is formed. The tooth portions 9a and 9b are the first and second pole pieces 4
The magnetic resistance is small at the position shown in the figure facing 1, 42,
The groove between the adjacent tooth portions has the first and second pole pieces 41, 4
The magnetic resistance increases at the position facing 2. Therefore, as the teeth 9a, 9b rotate, the magnetic resistance changes and the magnetic flux changes. This change in magnetic flux is detected as a voltage by the first detection coil 46. Also, the yoke 45
Has a curved shape so as to surround the pinion 5 as shown in FIGS.

Further, as shown in FIG. 7, the second rotation detector 35 is formed so as to face the magnetic protrusion 34 protruding on the outer peripheral side of the ring gear 9 at a predetermined radial air gap 40c. The third pole piece 50, the second iron core 51 interposed between the third pole piece 50 and the yoke 45, and magnetically connected to the both, and the bobbin 52a on the second iron core 51. A second detection coil 52 wound around the third pole piece 50, a second iron core 51, a yoke 45,
A magnetic closed circuit is formed by the permanent magnet 44, the second pole piece 42, the tooth portion 9b of the ring gear that faces the second pole piece 42, the ring gear 9, and the magnetic protrusion 34 that faces the third pole piece 50. It is configured to do. The magnetic resistance is small at the position where the magnetic protrusion 34 faces the third pole piece 50, and when the magnetic protrusion 34 no longer faces the third pole piece 50, the magnetic resistance increases. As a result, when the ring gear 9 rotates, the magnetic resistance changes,
The magnetic flux changes. This change in magnetic flux causes the second detection coil 52
Is detected as a voltage by.

Since this embodiment is constructed as described above, the following operational effects can be obtained. First, the rotation sensor 3
Since 0 is integrally attached to the end surface 8d of the attachment bracket of the starter 1, the rotation sensor 30 can be attached at the same time when the starter 1 is attached to the engine. Therefore, the processing of the engine block becomes unnecessary, and the man-hours for mounting the rotation sensor 30 on the engine block become unnecessary.

Since the first and second rotation detecting means 33 and 35 of the rotation sensor 30 form a magnetic closed circuit, even if there is a leakage magnetic flux from the outside, the magnetic flux change as a signal is large. It is possible to increase the S / N ratio. Therefore, it is possible to detect the engine rotation with high accuracy.

Further, the ring gear 9 has a variation in dimension in the axial direction, and the side surface of the ring gear has a relatively large deflection during rotation thereof, whereas the variation in dimension in the radial direction is small and the deflection in the radial direction is small. Few. Therefore, if the first and second pole pieces 41, 42 and the third pole piece 50 are made to face the tooth portion of the ring gear 9 and the magnetic projection piece via the air gap in the axial direction, It is necessary to make the gap size large, and the change in magnetic flux cannot be made large. In this embodiment, as described above, the first and second
Pole pieces 41, 42 and a third pole piece 50
Are opposed to the tooth portions 9a, 9b of the ring gear 9 and the magnetic protrusion 34 via the air gaps 40a, 40b, 40c in the radial direction, so that the gap size can be reduced and the magnetic flux change can be increased. Therefore, from this point as well, S / N
It is possible to detect the engine rotation with a large ratio and high accuracy.

Further, in the present embodiment, one rotation sensor 3
The first and second rotation detectors 33 and 35 are incorporated into 0, the crank angle is detected by the first rotation detector 33, and the top dead center is detected by the second rotation detector 35. The crank angle from can be easily detected.

Further, since the first and second iron cores 43, 51 and the permanent magnet 44 are magnetically connected via the curved yoke 45, the rotation sensor 30 is surrounded by the curved yoke 45 so as to surround the starter pinion 5. Can be mounted on the end surface 8d of the mounting bracket of the starter 1, and the rotation sensor 30 can be easily mounted on the starter 1 by effectively utilizing the small space left between the starter 1 and the ring gear 9.

[0031]

According to the present invention, since the rotation sensor is integrally attached to the starter, the rotation sensor can be easily attached and the engine block need not be processed.

Further, since the magnetic closed circuit is formed, the influence of the leakage magnetic flux is reduced and the engine rotation can be detected with high accuracy.

Since the pole piece and the tooth portion of the ring gear or the magnetic projection piece are opposed to each other by the air gap in the radial direction, the gap size can be reduced, and also from this point, it is possible to detect the engine rotation with high accuracy.

Since the first rotation detecting means for detecting the crank angle and the second rotation detecting means for detecting the top dead center are incorporated in one rotation sensor, the crank angle from the top dead center can be easily detected. can do.

Further, since the first and second iron cores and the permanent magnet are magnetically connected via the curved yoke, the rotation sensor can be effectively utilized by effectively utilizing the small space left between the starter and the ring gear. Can be easily attached to the starter.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view of a rotation sensor built-in starter according to an embodiment of the present invention.

FIG. 2 is a front view seen from the direction II-II in FIG.
The rotation sensor unit of FIG. 1 is illustrated in FIG.
The view is from the −I direction.

FIG. 3 is a front view of a rotation sensor.

FIG. 4 is a diagram showing an entire system for performing engine control by a signal from a rotation sensor shown in FIG.

5 is a flowchart of software for engine control performed by the system shown in FIG.

FIG. 6 is a configuration diagram of a first rotation detector incorporated in a rotation sensor.

FIG. 7 is a configuration diagram of a second rotation detector incorporated in the rotation sensor.

[Explanation of symbols]

 1 Starter 8 Mounting Bracket 8d End Surface 9 Ring Gear 9a, 9b Tooth Part 30 Rotation Sensor 33 First Rotation Detector 34 Magnetic Protrusion 35 Second Rotation Detector 40a, 40b, 40c Air Gap 41 First Pole Piece 42 Second pole piece 43 First iron core 44 Permanent magnet 45 Yoke 46 Detection coil 50 Third pole piece 51 Second iron core 52 Detection coil

Front page continuation (72) Inventor Masayuki Shizuka 2520 Takaba, Katsuta-shi, Ibaraki, Sawa Plant, Hitachi Ltd. (72) Inventor Shigeru Yumiyama 2520, Takaba, Katsuta-shi, Ibaraki Hitachi Sawa, Ltd. in the factory

Claims (6)

[Claims] 1. A starter for starting an engine by rotating a ring gear directly connected to an output shaft of an automobile engine, and an electromagnetic rotation sensor attached integrally to the starter for detecting rotation of the engine. The electromagnetic rotation sensor is magnetically connected to the first and second pole pieces, which are formed to face different tooth portions of the ring gear at predetermined air gaps. First rotation composed of a first iron core, a permanent magnet interposed between the first iron core and the second pole piece, and a first detection coil wound around the iron core. A magnetic closed circuit is formed by the detecting means, and the first and second pole pieces, the first iron core and the permanent magnet, the tooth portion of the ring gear facing the first and second pole pieces, and the ring gear. A starter with a built-in rotation sensor. 2. The starter with built-in rotation sensor according to claim 1, wherein the first and second pole pieces are formed so as to face a tooth portion of the ring gear with an air gap in a radial direction. A starter with a built-in rotation sensor. 3. The starter with a built-in rotation sensor according to claim 1, wherein the electromagnetic rotation sensor includes the second pole piece and a permanent magnet, and a magnetic protrusion that protrudes from an outer peripheral side portion of the ring gear. A third pole piece formed to face the magnetic protrusion with a predetermined air gap, and a second pole piece interposed between the third pole piece and the permanent magnet.
A second rotation detecting means including a second detection coil wound around the second iron core, the second and third pole pieces, the second iron core and a permanent magnet, Third
A starter with a built-in rotation sensor, characterized in that a magnetic closed circuit is formed by the magnetic protrusion and the tooth portion of the ring gear facing the second pole piece and the ring gear. 4. The starter with a built-in rotation sensor according to claim 3, wherein the first and second pole pieces and the third pole piece are arranged in a radial direction with respect to a tooth portion of the ring gear and a magnetic projection piece. A starter with a built-in rotation sensor, which is formed so as to face each other with a gap. 5. The starter with a built-in rotation sensor according to claim 1, wherein the electromagnetic rotation sensor further includes a curved yoke that magnetically connects the first and second iron cores to the permanent magnet. A starter with a built-in rotation sensor, wherein the electromagnetic rotation sensor is attached to an end surface of the starter so that the curved yoke surrounds a pinion that meshes with the ring gear. 6. A starter for rotating a ring gear directly connected to an output shaft of an automobile engine to start the engine, and an electromagnetic rotation sensor attached to the starter to detect rotation of the engine. The rotation sensor includes first and first magnetic protrusions that are provided on the outer peripheral side of the ring gear and face the magnetic protrusion and the tooth portion of the ring gear with predetermined gaps. Two pole pieces, an iron core magnetically connected to the first pole piece, a permanent magnet interposed between the iron core and the second pole piece, and a detection coil wound around the iron core. The rotation detecting means is provided, and the first and second pole pieces, the iron core and the permanent magnet, the magnetic projections facing the first and second pole pieces, the tooth portions of the ring gear, and the magnets of the ring gear. A starter with a built-in rotation sensor, which forms an air-closed circuit.