JP2008203272A - Method of manufacturing throttle opening detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a throttle opening detector capable of accurately detecting throttle opening by accurately fixing a permanent magnet in a resin gear by a smaller number of work manhours. <P>SOLUTION: The throttle opening detector is structured such that the resin gear 9 is connected to a throttle shaft 4 of a throttle valve 3; the permanent magnet is attached to a part of the resin gear 9; and the opening of the throttle valve 3 is detected by detecting the rotation angle of the resin gear 9 based on an output signal from a magnetic sensor 22 arranged on a fixation side by facing the permanent magnet without contacting it. A recessed boss part 9b is formed at the axis position of the resin gear 9, a yoke 20 and the permanent magnet 21 are attached along the inside surface of the boss part 9b, and the resin gear 9 is insert-molded by a synthetic resin by using the yoke 20 and the permanent magnet 21 as inserts. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a throttle opening detection device used in a throttle control device for an internal combustion engine, and more particularly, to detect the throttle opening in a non-contact manner using a permanent magnet, a yoke and a magnetic sensor. Relates to the device.

As a device for detecting the throttle opening of a throttle control device for an internal combustion engine, conventionally, a throttle opening sensor for detecting the rotation angle of a throttle shaft of a throttle valve in a non-contact manner using a permanent magnet and a magnetic sensor facing the permanent magnet. However, it is known from Patent Document 1 below.
JP 2001-132494 A

  A non-contact throttle opening sensor used in this type of throttle control device has a resin gear fixed to the end of the throttle shaft, and an annular permanent magnet divided into two at the boss of the resin gear. Then, a magnetic sensor is arranged in a non-contact manner inside the annular permanent magnet and attached to the fixed side, and the rotation angle of the resin gear is detected as the opening of the throttle valve based on the output signal output from the magnetic sensor. It is configured as follows.

  However, in this type of conventional throttle opening sensor, an annular permanent magnet is fixed by bonding with an adhesive in the recess of the boss portion of the resin gear fixed to the end of the throttle shaft. There are many work steps involved in bonding, and there is a problem that the fixed position of the permanent magnet varies depending on the product.

  In particular, since the outer peripheral portion of an annular permanent magnet is conventionally bonded to the inner peripheral portion of the concave portion of the boss portion with an adhesive, if the adhesive film thickness varies, the inner peripheral portion of the permanent magnet (magnetic The dimensional accuracy of the position (opposite the sensor) deteriorates, causing variations in the output level of the magnetic sensor, which adversely affects the detection accuracy of the throttle opening.

  The present invention solves the above-described problems, and can detect the throttle opening with high accuracy by fixing the permanent magnet in the resin gear with high accuracy and with less work man-hours. An object is to provide an apparatus.

  In order to achieve the above object, a throttle opening detection device according to the present invention has a resin gear coupled to a throttle shaft of a throttle valve, a permanent magnet is attached to a part of the resin gear, and the permanent magnet is not in contact with the fixed side. In a throttle opening detection device that detects the rotation angle of a resin gear based on an output signal from a magnetic sensor arranged oppositely at a position and detects the opening of a throttle valve, a concave boss is formed at the axial center of the resin gear. Part is formed, the yoke and permanent magnet are attached along the inner peripheral surface of the boss part, and the resin gear is insert-molded with the yoke and permanent magnet as an insert, and the yoke is formed into an annular shape by combining the divided arc parts And a permanent magnet is disposed between the divided yoke and the yoke, and the yoke and the permanent magnet are coated with a synthetic resin on the outer peripheral surface, the upper end surface and the lower end surface except for the inner peripheral surface thereof. , The peripheral portion of the boss portion of the resin gear, characterized in that the grooves reach the outer periphery of the yoke and the permanent magnet is formed.

  Further, as in claim 2, the boss portion of the resin gear is insert-molded with a metal member for coupling the throttle shaft as an insert, and a part of the metal member is extended to the outer peripheral portion of the yoke and the permanent magnet. A part of the metal member can be brought into contact with the outer peripheral surface of the permanent magnet.

  In the throttle opening detection device having the above configuration, since the yoke and the permanent magnet are used as inserts, insert molding is performed on the inner peripheral portion of the boss portion when molding the resin gear. Compared to the case of bonding to a resin gear, the number of work steps can be greatly reduced, and the permanent magnet and yoke can be fixed at a predetermined position with high accuracy, thereby detecting the throttle opening with high accuracy. Can do.

  In particular, when insert molding a resin gear, if the mold is aligned with a permanent magnet and a yoke set in the mold, for example, the inner periphery and part of the upper surface of the permanent magnet and the yoke are in contact with the mold. The permanent magnet and the lower surface of the yoke are pressed by the mold pin, and in this state, the material is injected into the mold and molded.

  For this reason, the yoke and permanent magnet disposed in the boss part are molded such that a part of the outer peripheral surface, the upper end surface and the lower end surface excluding the inner peripheral surface thereof are covered with synthetic resin, and the boss part of the resin gear A groove reaching the outer peripheral surface of the yoke and the permanent magnet is formed as a trace of the pressing portion of the mold. Therefore, when molding resin resin inserts, the permanent magnet and yoke are pressed precisely in place in the mold as described above, so the permanent magnet and yoke are fixed to the boss of the resin gear with high precision. can do.

  In the throttle opening detecting device, a resin gear is coupled to a throttle shaft of a throttle valve, and a magnetic sensor is disposed on the fixed side in a non-contact manner in a concave boss portion of the resin gear. The gear rotates, and similarly, the permanent magnet and the yoke in the resin gear rotate, and the rotation angle, that is, the opening degree of the throttle valve is detected by the magnetic sensor.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of a throttle control device for an internal combustion engine. In this throttle control device, the throttle shaft 4 is rotated via a gear mechanism by driving a control motor 13, the throttle valve 3 on the shaft is opened and closed, and the throttle opening degree for detecting the opening degree of the throttle valve 3 is detected. It is provided with a detection device. Reference numeral 1 denotes a throttle body. An intake passage 15 is formed inside the throttle body 1, and a butterfly-type rotary throttle valve 3 is disposed so as to open and close the intake passage 15 via a throttle shaft 4. Is done.

  A throttle shaft 4 is fixed at the center of the throttle valve 3, and both ends of the throttle shaft 4 are rotatably supported by a rolling bearing 5 and a metal bearing 16. A substantially cup-shaped spring seat 6 is fixed to the end of the throttle shaft 4 on the side of the rolling bearing 5, a return torsion coil spring 7 is interposed between the spring seat 6 and the throttle body 1, and the throttle valve 3 is urged in the closing direction.

  Further, a rotational drive resin gear 9 for rotating the throttle valve 3 is fitted to the end of the throttle shaft 4, and a small torsion coil spring 8 is interposed between the resin gear 9 and the spring seat 6. ing. A permanent magnet 21 constituting a part of the throttle opening degree detecting device and a yoke 20 constituting a magnetic circuit are integrally fixed to the resin gear 9 by insert molding as follows.

  As shown in FIG. 2, the resin gear 9 has a gear portion 9a formed at a part of the outer peripheral portion, and a concave boss portion 9b formed at the central portion to which the throttle shaft 4 is fixed. A metal plate 17 for connecting the throttle shaft to the bottom is disposed. A rectangular hole 17a is formed in the center of the metal plate 17 so that the end of the throttle shaft 4 is fitted at a predetermined angle. The metal plate 17, the permanent magnet 21, and the yoke 20 are integrally insert-molded when the resin gear 9 is molded, and are fixed and arranged at predetermined positions with high dimensional accuracy.

  As shown in the sectional views of FIGS. 3 and 4, the concave boss portion 9b is formed as a circular cup-shaped concave portion, and a permanent magnet 21 and a yoke 20 as shown in FIG. The yoke 20 is formed in an annular shape divided into two, and the two semicircular arc-shaped yokes 20 are arranged to face each other to form a circle. Further, a prismatic permanent magnet 21 is interposed in a wide portion where both ends of the yokes 20 on both sides are matched.

  That is, as shown in FIG. 5, thick collar portions 20a are formed at both ends of two semicircular arc shaped yokes 20, and a prismatic permanent magnet 21 is sandwiched between the collar portions 20a. Two semi-arc shaped yokes 20 are arranged. At the time of molding the resin gear 9, these two permanent magnets 21 and two yokes 20 are inserted into a predetermined position in the mold together with the metal plate 17, and insert molding is performed. The positioning of the permanent magnet 21 and the yoke 20 in the boss portion 9b is performed with a small number of steps and with high accuracy.

  As can be seen from the plan view of FIG. 2 and the cross-sectional views of FIGS. 3 and 4, an annular groove 9 c is formed around the concave boss portion 9 b of the resin gear 9, and the groove 9 c is a boss of the resin gear 9. The permanent magnet 21 embedded in the inner peripheral portion of the portion 9b and part of the outer peripheral portion of the yoke 20 are reached. Similarly, a hole is formed around the boss 9 b on the back surface side (metal plate side) of the resin gear 9, and the hole reaches part of the outer periphery of the permanent magnet 21 and the yoke 20.

  The resin gear 9 having such a shape is molded by injection molding of a synthetic resin using a predetermined mold. At the time of molding, the permanent magnet 21 and the yoke 20 inserted into the mold as inserts are: The inner peripheral surface is pressed by a part of the mold, and the outer peripheral part including the flange part 20a of the yoke 20 is pressed by a part of the mold to be molded. At the time of molding, the upper surfaces of the permanent magnet 21 and the yoke 20 are pressed by a mold, and the lower surfaces are pressed by a mold pin biased by a spring, and insert molding is performed in this state. Then, by performing such insert molding, as shown in FIGS. 2 to 4, the resin rotates around the outer peripheral portion and the upper and lower surfaces of the permanent magnet 21 and the yoke 20 of the molded resin gear 9. The permanent magnet 21 and the yoke 20 are fixed in place by resin.

  Therefore, at the time of injection molding of the resin gear 9, it is insert-molded in a state where the permanent magnet 21 and the yoke 20 are held with high precision in the mold, and the resin gear 9 is a molded product in the boss portion 9b of the resin gear 9. The permanent magnet 21 and the yoke 20 are positioned and fixed and held with high accuracy.

  On the other hand, as shown in FIG. 1, a motor storage portion 1a is formed in the upper portion of the throttle body 1, and a control motor 13 for opening and closing the throttle valve 3 is stored in the motor storage portion 1a. A pinion gear 14 is fixed to the rotation shaft of the control motor 13, and the pinion gear 14 meshes with the large-diameter gear 12 a of the reduction intermediate gear 12. The intermediate gear 12 has a large-diameter gear 12a and a small-diameter gear 12b, and is rotatably supported by a gear shaft 11 that is pivotally supported in the throttle body 1. The resin gear 9 is disposed in mesh with the small-diameter gear 12 b of the intermediate gear 12, and the resin gear 9 is rotated via the intermediate gear 12 by the rotational drive of the control motor 13, so that the throttle gear coaxial with the resin gear 9 is provided. The valve 3 rotates and is controlled to open and close.

  Further, the cover body 2 is fitted on the gear arrangement side of the throttle body 1 so as to cover the portion. The cover body 2 is fitted in an accurate position by fitting a fitting portion provided on the throttle body 1 side with a fitting portion formed corresponding to the fitting portion. At the position corresponding to the concave boss portion 9b of the resin gear 9 inside the cover body 2, a sensor mounting portion 2a protrudes and is formed on the sensor mounting portion 2a, as shown in FIGS. A magnetic sensor 22 is attached.

  The magnetic sensor 22 is configured by using a Hall element, a Hall IC, a magnetoresistive element, and the like, and is disposed at a position on the central axis provided in the sensor mounting portion 2a with its magnetic detection surface facing outward. A voltage signal or the like corresponding to the strength is output. The cover body 2 is integrally formed of synthetic resin together with the sensor mounting portion 2a. At the time of molding, the magnetic sensor 22 can be insert-molded as an insert at the predetermined position as described above.

  By fitting such a cover body 2 at a fixed position of the throttle body 1, the sensor mounting portion 2a is accurately positioned in a non-contact state within the concave boss portion 9b of the resin gear 9. Inserted. In this state, as shown in FIG. 7, the magnetic detection surface of the magnetic sensor 22 is disposed so as to face the permanent magnet 21 positioned on the outer peripheral side and the inner peripheral surface of the yoke 20 in a non-contact manner.

  When magnetism is applied by the permanent magnets 21 on both sides, for example, when an N pole is generated in the upper yoke 20 and an S pole is generated in the lower yoke 20, a sensor arranged in a circular shape including two semicircular arc shaped yokes 20 is combined. A magnetic path that flows from the yoke to the yoke through the magnetic detection surfaces on both sides of the magnetic sensor 22 is formed in the magnetic sensor 22 in the mounting portion 2a. The strength of the magnetic field flowing in the magnetic path crossing between the yokes varies depending on the angle of the magnetic sensor 22 with respect to the yoke 20 and the permanent magnet 21. The output voltage of the magnetic sensor 22 changes according to the strength of the detected magnetic field, and a voltage signal indicating the rotation angle of the resin gear 9, that is, the throttle valve 3 is output.

  The throttle opening degree detecting device includes such a permanent magnet 21, a yoke 20, and a magnetic sensor 22. The magnetic sensor 22 is on the fixed side, and the angle of the rotating resin gear 9, that is, the opening degree of the throttle valve 3 is determined. , Detected from the output signal of the magnetic sensor 22. The output side of the magnetic sensor 22 is connected to a detection circuit and an engine control controller provided outside through a terminal portion (not shown) provided in the cover body 2.

  For example, when the driver depresses an accelerator pedal, the throttle opening is detected by an accelerator opening sensor, and the opening signal is sent to an engine control controller. The engine control controller outputs a drive signal corresponding to the accelerator opening signal, that is, a drive signal to the control motor 13 so that the opening of the throttle valve 3 becomes an opening corresponding to the accelerator opening. The control motor 13 rotates.

  The rotation of the control motor 13 is transmitted to the intermediate gear 12 via the pinion gear 14, and the rotation of the intermediate gear 12 causes the resin gear 9 to rotate via the large diameter gear 12a and the small diameter gear 12b. As a result, the throttle shaft and the throttle valve 3 are rotated by a predetermined rotation angle against the biasing force of the torsion coil spring 7, and the throttle valve 3 is held at that angle in the intake passage 15.

  At this time, the magnetic sensor 22 of the throttle opening detection device outputs a detection signal corresponding to the rotation angle of the resin gear 9, that is, the opening of the throttle valve 3, and the controller for engine control uses this signal as a throttle opening signal. Input and used for calculating the fuel injection amount of the engine.

  As described above, the permanent magnet 21 and the yoke 20 constituting the throttle opening detecting device are disposed at fixed positions in the mold as inserts when the resin gear 9 is injection-molded, and are integrally insert-molded. Thus, compared with the case where the permanent magnet 21 and the yoke 20 are bonded to a predetermined position using an adhesive, the number of work steps can be reduced, and the productivity can be improved and the manufacturing cost can be reduced by reducing the number of steps.

  Further, the permanent magnet 21 and the yoke 20 are molded by injecting resin into the mold in a state where the permanent magnet 21 and the yoke 20 are accurately positioned by a part of the mold or a mold pin from the inner peripheral surface side. The accuracy of the position of the permanent magnet 21 and the yoke 20 in the resin gear 9 is less compared with the case of bonding with a conventional adhesive and is highly accurate. Therefore, the opening degree of the throttle valve can be detected with high accuracy.

  8 to 12 show a resin gear 39 or the like according to another embodiment. Instead of the metal plate 17, a substantially cup-shaped metal member 37 is embedded in the resin gear 39 in this example for coupling the throttle shaft. The same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In other words, the throttle shaft coupling metal member 37 is insert-molded in the boss portion 39 a of the resin gear 39. A gear portion 39a similar to the above is formed in a part of the resin gear 39, and the yoke 20 and the permanent magnet 21 are arranged in an annular shape by insert molding on the inner peripheral portion of the boss portion 39a formed in a circular concave shape. And fixed. As shown in FIGS. 8 to 10, the metal member 37 is formed in a substantially cup shape, a rectangular hole 37 a for shaft coupling is formed at the bottom, and openings 37 c are formed at two locations on both sides of the bottom. An annular portion is formed above the opening 37c, and the annular portion extends to the outer periphery of the yoke 20 and the permanent magnet 21 fixed to the inner periphery of the boss portion 39a. The opening 37c is an opening for pressing and supporting the permanent magnet 21 with a mold pin or the like from the lower side when the resin gear 39 is insert-molded using the metal member 37 as an insert.

  Further, at the time of the insert molding, as shown in FIG. 12, a part of the annular portion is brought into contact with the outer surface of the yoke 20 and the permanent magnet 21 as a pressing portion 37 b, and by the pressing portion 37 b of the metal member 37, Positional displacement between the yoke 20 and the permanent magnet 21 during insert molding is prevented. That is, during injection molding of the resin gear 39, the inserted yoke 20 and the permanent magnet 21 are likely to be displaced outward due to linear expansion of the resin material, but the pressing portion 37b of the metal member 37 is the outer peripheral portion of the yoke 20 and the permanent magnet 21. It is possible to prevent the positional deviation between the yoke 20 and the permanent magnet 21 in the boss portion 39a.

  As described above, according to the throttle opening detection device of the present invention, the resin gear is insert-molded so that the yoke and the permanent magnet are used as inserts at the inner peripheral portion of the boss portion at the time of molding. Compared to the case where a permanent magnet is bonded to a resin gear using an adhesive as in the past, the number of work steps can be greatly reduced, and the permanent magnet and yoke can be fixed at a predetermined position with high accuracy without variation in position. This makes it possible to detect the throttle opening with high accuracy.

  Also, by resin molding the resin gear, the outer peripheral surface, the upper end surface, and a part of the lower end surface of the yoke and permanent magnet other than the inner peripheral surface of the boss portion are covered with a synthetic resin, and the resin gear is formed. Since the groove reaching the outer peripheral surface of the yoke and the permanent magnet is formed in the peripheral portion of the boss portion of the mold, when the resin gear is insert-molded, when the mold is matched with the permanent magnet and the yoke set in the mold, for example, The inner periphery and part of the upper surface of the permanent magnet and yoke are pressed against the mold, and the lower surface of the permanent magnet and yoke are pressed by the mold pin. In this state, the material is injected into the mold. Can be molded. Therefore, at the time of insert molding of the resin gear, the permanent magnet and the yoke are accurately pressed at a fixed position of the mold, and the permanent magnet and the yoke can be fixed to the boss portion of the resin gear with high accuracy.

It is sectional drawing of the throttle control apparatus which shows one Embodiment of this invention. 3 is a plan view of a resin gear 9. FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is IV-IV sectional drawing of FIG. 2 is a perspective view of a permanent magnet 21 and a yoke 20. FIG. It is a perspective view of the magnetic sensor with which the cover body side sensor mounting part 2a was mounted | worn. It is a top view of the sensor mounting part 2a and the resin gear 9. It is a top view of the metal member 37 for axis | shaft coupling of other embodiment. 4 is a sectional view of the metal member 37. FIG. 4 is a bottom view of the metal member 37. FIG. It is sectional drawing of the resin gear 39 using the metal member. It is sectional drawing of the resin gear 39 using the metal member.

Explanation of symbols

1-throttle body 3-throttle valve 4-throttle shaft 9-resin gear 9a-tooth portion 9b-boss portion 9c-groove 20-yoke 21-permanent magnet 22-magnetic sensor

Claims (2)

A resin gear is coupled to the throttle shaft of the throttle valve, a permanent magnet is attached to a part of the resin gear, and based on an output signal from a magnetic sensor arranged on the fixed side so as to face the permanent magnet in a non-contact manner, In a throttle opening detection device for detecting the rotation angle of the resin gear and detecting the opening of the throttle valve,
A concave boss is formed at the axial center of the resin gear, and a yoke and a permanent magnet are attached along the inner peripheral surface of the boss. The resin gear is insert-molded using the yoke and the permanent magnet as an insert. The yoke is formed in an annular shape by combining the divided arc portions, and a permanent magnet is arranged between the divided yoke and the yoke, and the yoke and the permanent magnet have an outer periphery excluding an inner peripheral surface thereof. The throttle opening is characterized in that a part of the surface, the upper end surface and the lower end surface are covered with a synthetic resin, and a groove reaching the outer peripheral surface of the yoke and the permanent magnet is formed in a peripheral portion of the boss portion of the resin gear. Degree detection device.   A metal member for coupling the throttle shaft is insert-molded in the boss portion of the resin gear, and a part of the metal member is extended to the outer peripheral portion of the yoke and the permanent magnet. The throttle opening degree detecting device according to claim 1, wherein a part of the metal member is in contact.

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