JP2008309598A - Angle detecting sensor and take-in air amount control device having it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that owing to long size of shorting ring coil (printed conductor), resistance of the shorting ring coil is so large that generated induction current can not be enlarged enough and induction current to a detection coil at a stator side can not be enlarged, so the change in the electromagnetic induction coupling between the electromagnetic coil and the detection coil of the stator is small, as a result, an angle detecting sensor with high precision can not be provided. <P>SOLUTION: In a rotor part, first plural shorting ring coils, each of them is electrically insulated, which are periodically arranged along a rotation direction and a second shorting ring coil, being insulated from the first plural shorting ring coils, of which a part closes to the first plural shorting ring type coils so as to surround the periphery of the rotational axis. As a result, the angle sensor capable of increasing output with high precision can be provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an angle detection sensor that detects a rotation angle of a rotary shaft in a non-contact manner, and also relates to an intake air amount control device for an internal combustion engine equipped with the angle detection sensor.

  This kind of angle detection sensor that detects the rotation angle, such as a steering wheel of an automobile or an intake air amount control device (also called a throttle valve) of an internal combustion engine, detects an electromagnetic coil attached to a stator by rotation of a rotor attached to a rotating shaft. It is known to change the electromagnetic inductive coupling with the coil and detect the rotation angle from the change in the strength (inductance) of the electromagnetic inductive coupling.

European Patent EP159191 US Patent US6236199 JP-T-2001-520368

  In the angle detection sensor described in the prior art documents (Patent Documents 1, 2 and 3), the short ring coil (printed conductor) of the rotor has a long dimension, so the resistance of the short ring coil is large and occurs. The induced current cannot be increased sufficiently. For this reason, the current induced in the detection coil on the stator side cannot be increased, the change in electromagnetic induction coupling between the stator electromagnetic coil and the detection coil is small, and as a result, a highly accurate angle detection sensor cannot be provided. There is.

  Accordingly, an object of the present invention is to obtain this kind of angle detection sensor that can sufficiently obtain the output of the short ring coil and does not deteriorate the detection accuracy of the rotation angle due to insufficient sensitivity.

  The object is to arrange a plurality of first short ring-shaped coils that are electrically insulated from each other on the rotor portion arranged close to the excitation coil of the stator portion at a specific interval in the rotation direction of the rotor, and This is achieved by disposing a second short ring coil that is electrically insulated from the coil and disposed around the rotation axis and at least partially adjacent to the plurality of first short ring coils.

  According to the present invention configured as described above, since the coil length of the short ring coil is shortened and the coil resistance can be greatly reduced, each short ring coil due to the eddy current effect (back electromotive force) due to the excitation field is provided. A decrease in the flowing current is suppressed, and the canceling magnetic field works effectively. As a result, the change in the strength of the electromagnetic inductive coupling can be increased, and the output of the detection coil is increased, so that a highly accurate angle detection sensor can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. First, the prior art described in Patent Document 2 will be described in comparison with an embodiment of the present invention.

  Hereinafter, the angle detection sensor of Patent Document 2 will be described. The overall configuration of the angle detection sensor is as shown in FIG.

  The stator portion includes an excitation coil A5, a plurality of detection coils A6, and a processing circuit A7 formed on the upper surface of the printed circuit board 2. The processing circuit A7 includes an oscillation circuit for causing an alternating current to flow through the exciting coil A5 and an arithmetic processing circuit for calculating the rotation angle of the rotor from the outputs of the plurality of detection coils A6.

  The rotor portion is composed of a printed circuit board A4 that is disposed close to the end surface of the rotation shaft 3 that rotates with respect to the rotation center axis A10 so as to be spaced apart from the stator portion by a predetermined distance and to coincide with the rotation center axis. In the printed circuit board A4, FIG. A one-turn short coil shape A20 (see FIG. 18) described in 6c is formed.

  FIG. 12 shows a top view of the coil pattern of the stator portion. The detection coils A6a, A6b, and A6c are composed of six meandering coils that are repeated at intervals of 60 degrees in the rotation direction inside the excitation coil A5, and each of the detection coils A6a, A6b, and A6c is phase-shifted by 20 degrees. It has a configuration.

  FIG. 13 shows a configuration in which each detection coil A6a, A6b, A6c is developed in a simulated manner in the linear direction. Each detection coil A6a, A6b, A6c is one closed loop which starts from the output ends S1, S2, S3 and returns while crossing so as to form an 8-shaped coil. The closed loop of each detection coil is composed of a combination of six coil regions whose phases are reversed with respect to the cross portion. The six coil regions have the same coil area, and the in-phase and three-phase total coil areas of three in-phase and three in-phase are equal.

  By configuring the detection coil in this way, in the state where there is no influence of the electromagnetic induction coupled rotor (zero rotation), the magnetic field generated by the excitation coil A5 interlinks the closed loops of the detection coils with the same phase and Since cancellation is performed in the reverse phase, the outputs (induced electromotive voltages) of the output terminals S1, S2, and S3 become zero. In addition, electromagnetic induction noise from the outside is similarly canceled and is not affected, so that the structure is strong against external noise.

  FIG. 18 shows FIG. FIG. 19 shows the positional relationship of the one-turn short coil shape A20 of the rotor portion described in 6c as viewed from the top surface of the stator portion and the rotor portion in Patent Document 2. FIG. 19 shows only the detection coil A6a among the detection coils A6a, A6b, A6c on the stator side. The rotor portion in which the one-turn short coil A20 is formed around the rotation center axis 10 rotates.

  A high frequency current A11 from the oscillation circuit in the processing circuit A7 flows counterclockwise in the excitation coil A5, and an excitation field is generated in the excitation coil A5 from the back side to the front side. On the other hand, the counter electromotive force due to the eddy current effect caused by the excitation field of the excitation coil A5 acts on the one-turn short coil A20 of the rotor portion arranged in proximity, and the current A12a flows in the clockwise direction. Accordingly, a magnetic field is generated in a direction canceling the excitation field of the excitation coil A5 in the inner region of the short coil A20.

  As shown in FIG. 19, in the state where the detection coil A6a on the stator side and the short coil A20 on the rotor side partially overlap each other, the in-phase and reverse-phase magnetic fluxes that link the closed loop of the detection coil A6a are unbalanced and detected. An output (inductive electromotive voltage) is generated at the output terminal S1 of the coil A6a. The output changes depending on the overlapping state of the in-phase and anti-phase closed loops of the detection coil A6a and the rotor-side short coil A20 (the difference between the in-phase and anti-phase closed loop areas excluding the short coil region).

  FIG. 14 shows the outputs U1, U2, U3 of the output ends S1, S2, S3 of the detection coils A6a, A6b, A6c on the stator side. The three-phase output is a sine wave with respect to the rotation angle of the rotor, and each output has a phase difference of 20 degrees. By comparing the output values of the outputs U1, U2 and U3 in the processing circuit A7, the rotation angle can be measured in the region of the rotation angle of 60 degrees.

  The angle detection sensor of Patent Document 2 configured as described above has the following problems.

  20 and 21 show the BB ′ cross section and the AA ′ cross section and the magnetic flux density (B) distribution of the angle detection sensor of Patent Document 2 shown in FIG. In the BB ′ cross section of FIG. 20, since the rotor-side short coil A20 is located inside the detection coil A6a region, the canceling magnetic field A14 generated by the short coil A20 does not affect the detection coil A6a region. Only the excitation field A13 from the excitation coil A5 is linked to the detection coil A6a.

  On the other hand, in the AA ′ cross section shown in FIG. 21, since the rotor-side short coil A20 overlaps the detection coil A6a region, the cancel magnetic field A14 generated by the short coil A20 is generated in the detection coil A6a region. The magnetic flux density (B) distribution of the cancellation magnetic field A14 from the excitation field A13 and the short coil A20 from the excitation coil A5 is shown in the lower part of FIG. The magnetic flux density (B) distribution of the excitation field A13 is a solid line A15, the magnetic flux density (B) distribution of the cancellation magnetic field A14 is a broken line A16, and the directions are opposite to each other, but only the absolute value of the intensity is shown.

  As both the excitation field A13 and the cancellation magnetic field A14 move away from the excitation coil A5, the magnetic field strength (magnetic flux density) decreases. The original ideal is that the canceling magnetic field A14 coincides with the excitation field A13 and completely cancels the excitation field A13, so that the interlinkage magnetic flux in the overlapping region of the coil becomes completely zero, and the in-phase from the detection coil A6a The difference is that the negative-phase closed-loop area difference (output) is maximized. However, in the conventional example of Patent Document 2, the cancel magnetic field A14 (broken line A16) is weakened.

  This is because, as shown in FIG. 19, the short coil A20 of one turn is routed around the rotor, so that the coil length is increased and the coil resistance is increased. This is because the current A12a due to) decreases.

  As described above, the angle detection sensor of Patent Document 2 has a problem that the output of the detection coil is not sufficient and the detection accuracy of the rotation angle is deteriorated due to insufficient sensitivity.

  In Patent Document 2, another example of a short coil of a rotor portion as shown in FIG. 22 (FIG. 6d of Patent Document 2) is described. An annular short coil A21 is formed which is electrically connected to the inner periphery of the short coil A20.

  In the coil configured in this manner, the coil resistance is reduced because the short coil A20 and the short coil A21 are connected in parallel. However, the cancellation current due to the eddy current effect (back electromotive force) due to the excitation field of the excitation coil A5 branches into A12c and A12d as shown in FIG. In particular, the cancel current A12c of the short coil A20 in the detection coil region that affects the output decreases by the current A12d branched to the short coil A21, so the cancel effect is weakened and the output decreases.

  FIG. 11 shows a rotation angle detection sensor of the present invention. The stator portion has the same configuration (indicated by the same reference numerals) as the conventional example of Patent Document 2 shown in FIGS. The rotor portion is composed of a printed circuit board A4 that is disposed close to the end surface of the rotation axis A3 that rotates with respect to the rotation center axis A10 so as to be spaced apart from the stator portion by a predetermined distance so that the rotation center coincides.

  A coil pattern shown in FIG. 10 is formed on the printed circuit board A4. A8a, A8b, A8c, A8d, A8e, A8f are a plurality of first short ring coils that are electrically insulated from each other in the rotation direction at the periphery of the rotor adjacent to the exciting coil. This is a second short ring-shaped coil that is electrically insulated from the short ring-shaped coil, and is formed so that a part thereof is close to the first plurality of short ring-shaped coils and includes the rotation axis A10.

  FIG. 15 shows the positional relationship seen from the top surface of the stator portion and the rotor portion of the present invention. FIG. 15 shows only the detection coil A6a among the detection coils A6a, A6b, A6c on the stator side. The rotor portion in which the first plurality of short ring coils A8a, A8b, A8c, A8d, A8e, A8f and the second short ring coil A9 are formed around the rotation center axis A10 rotates.

  A high frequency current A11 from the oscillation circuit in the processing circuit A7 flows counterclockwise in the excitation coil A5, and an excitation field from the back side to the front side is generated inside the closed loop of the excitation coil A5. On the other hand, the first plurality of short ring-shaped coils A8a, A8b, A8c, A8d, A8e, A8f and the second short ring-shaped coil A9 of the rotor portion arranged close to each other are caused by the excitation field of the excitation coil A5. The counter electromotive force due to the eddy current effect works and currents A12a and A12b flow in the respective short ring coils in the clockwise direction. Accordingly, a magnetic field is generated in the direction of canceling the excitation field of the excitation coil A5 in the closed loop inner region of each short ring coil.

  As shown in FIG. 15, in a state where the detection coil A6a on the stator side and the first plural short ring coils A8a, A8b, A8c, A8d, A8e, A8f on the rotor side partially overlap, the closed loop of the detection coil A6a is formed. An imbalance occurs in the interlinkage magnetic flux, and an induced electromotive voltage (output) is generated at the output terminal S1 of the detection coil A6a. The output is an overlap state of the closed loop of the detection coil A6a and the closed loop of the short ring coils A8a, A8b, A8c, A8d, A8e, A8f on the rotor side (difference in closed loop area between the in-phase and the reverse phase excluding the short ring coil region). It depends on.

  FIG. 14 shows outputs U1, U2, U3 of the output ends S1, S2, S3 of the detection coils A6a, A6b, A6c on the stator side. The three-phase output is a sine wave with respect to the rotation angle of the rotor, and each output has a phase difference of 20 degrees. By comparing the output values of the outputs U1, U2 and U3 in the processing circuit A7, the rotation angle can be measured in the region of the rotation angle of 60 degrees.

  FIG. 16 shows a CC ′ cross section and a magnetic flux density (B) distribution of the angle detection sensor shown in FIG. In the CC ′ cross section shown in FIG. 15, since the first short ring-shaped coil A8e on the rotor side overlaps the region of the detection coil A6a, the canceling magnetic field A14 generated by the short ring-shaped coil A8e is the same as that of the detection coil A6a. Occurs in the closed loop region.

  The magnetic flux density (B) distribution of the excitation field A13 from the excitation coil A5 and the canceling magnetic field A14 by the short ring coil A8e is shown in the lower part of FIG. The magnetic flux density (B) distribution of the excitation field A13 is a solid line A15, the magnetic flux density (B) distribution of the cancellation magnetic field A14 is a broken line A17, the direction is reversed, and only the absolute value of intensity is shown. For comparison, the magnetic flux density (B) distribution of the cancellation magnetic field in the conventional example of Patent Document 2 is shown by a broken line A16.

  Both the excitation field A13 and the cancellation magnetic field A14 decrease in magnetic field strength as they move away from the excitation coil A5. In the embodiment of the present invention, the canceling magnetic field A14 (see the broken line A17) coincides with the excitation field A13 (see the solid line A15) to completely cancel the excitation field A13, so that the interlinkage magnetic flux in the region where the coils overlap is completely obtained. Thus, the closed-loop area difference (output) between the in-phase and anti-phase from the detection coil A6a is maximized. On the other hand, it can be seen that the cancellation magnetic field A14 (see the broken line A16) in the conventional example of Patent Document 2 is weak against the excitation field A13 (see the solid line A15) and cannot be canceled sufficiently.

  Thus, as shown in FIG. 15, the factor of the effect of the present invention is that the first plurality of short ring coils A8a, A8b, A8c, A8d, A8e, A8f are arranged close to the exciting coil A5, and This is because the short ring-shaped coil becomes a closed loop that is subdivided, so that the coil length is shortened and the coil resistance can be greatly reduced. By reducing the coil resistance, a decrease in the current A12a flowing through each short ring coil due to the eddy current effect (back electromotive force) due to the excitation field is suppressed, and the cancel magnetic field A14 (see the broken line A17) works effectively. .

  In the conventional example of Patent Document 2 shown in FIG. 21, the cancel current A12a flows only to one end in the vicinity of the excitation coil A5 of the short ring coil 20, but in the present embodiment, as shown in FIG. In addition, the canceling magnetic field A14 (see the broken line A17) works more effectively because it flows in the vicinity of the exciting coil A5 of the short ring coil A8e and both ends of the folded coil portion.

  Further, the second short ring-shaped coil A9 is electrically insulated from the first plurality of short ring-shaped coils, and a part thereof is close to the first plurality of short ring-shaped coils and includes the rotation axis A10. Due to the formation, the cancel current A12b also flows in the second short ring coil A9. Although the cancellation magnetic field tends to decrease as the distance from the excitation coil increases, the cancellation magnetic field A18 is generated particularly in the central axis side region of the detection coil A6a by installing the second short ring coil A9. Further, a canceling effect can be obtained effectively.

  In the embodiment of the present invention configured as described above, the electromagnetic induction coupling rotor can be optimized as compared with the conventional example as described above, so that the output can be increased and a highly accurate angle detection sensor can be provided. .

  As another example, FIG. 17 is electrically insulated from the first plurality of short ring coils A8a, A8b, A8c, A8d, A8e, A8f and the first plurality of short ring coils, and a part thereof is the first. The second short ring-shaped coil 9 formed so as to be close to the plurality of short ring-shaped coils and to include the rotation axis A10 is shown.

  The effect is the same as in the previous embodiment, but the first plurality of short ring coils are further closed on the exciting coil A5 side to form a small closed loop, and the second short ring coil 9 is removed from the ring. The meandering closed loop shape was adopted. For this reason, the first short ring coil having a small area closed loop further reduces the coil resistance, and the canceling effect is effectively obtained. Further, the canceling effect can be more effectively obtained by setting the proximity portions of the first plurality of short ring coils and the second short ring coils as close as possible while ensuring electrical insulation.

  By forming the exciting coil of the stator portion, the plurality of detection coils, and the short ring-shaped coil of the rotor portion by a printed circuit board circuit, a low-cost and highly accurate angle detection sensor can be provided.

  Although the embodiment of the present invention has been described above, in the embodiment, the three-phase output with three detection coils is used, but the configuration of the two-phase output with two detection coils also changes the effect of the present invention. No. Moreover, although the phase difference of each detection coil was 20 degrees, it is good also as another angle relationship. Applying the number and arrangement of the rotor coil patterns of the present invention corresponding to such various detection coils can be easily analogized by those skilled in the art.

  Next, an intake air amount control device (throttle valve) of an internal combustion engine (for example, for a diesel engine) using the rotation shaft angle detection sensor according to the present invention will be described in detail.

  An example of a rotation angle detection device in which the present invention is implemented will be described with reference to FIGS.

  As shown in FIG. 1, a low-cylindrical (cup-shaped) holder 1B made of a resin molded body is attached to the tip of the rotating shaft 1A. A disc 1C made of an insulating material is fixed to the front end surface of the holder 1B by adhesion. An annular recess 1E is formed on the front end surface of the holder 1B. An adhesive is poured into the recess 1E, and the disk 1C is placed thereon and bonded. An excitation conductor 1D, which will be described later, is printed on the surface of the disk 1C (the surface opposite to the bonding surface).

  Grooves extending in the axial direction and ridges extending in the axial direction are alternately formed around the cylindrical portion of the holder 1B, and the grooves and ridges around the holder 1B are formed on the inner peripheral surface of the rotating body 1A. On the other hand, an uneven portion is formed so as to constitute the fitting portion 1K. Both are mating surfaces and may be bonded by an adhesive. Thus, the fitting portion 1K stops around the holder 1B and also functions as positioning.

  The excitation conductor 1D includes a set of three linear portions 1D1 extending radially and arc-shaped portions 1D2 and 1D3 provided so as to connect the inner peripheral side and the outer peripheral side of the adjacent linear portions 1D1. The straight line portions 1D1 are arranged at six positions with an interval of 60 degrees from each other. As a result, as shown in FIG. 2, three closed loop short ring coils (first short rings) are arranged at equal intervals.

  An annular short ring 1D9 (second short ring-shaped coil) is provided on the inner peripheral portion of the three closed loop short ring-shaped coils while maintaining electrical insulation.

  The sensor case 2A is provided with a circular window hole 2B having a diameter slightly larger than the diameter of the holder 1B. A small annular protrusion 2C is formed around the window hole 2B. In the case 2A, a wall portion 2D that forms a space for housing the detection portion around the window hole 2B is formed by resin molding.

  Adhesive 2E is poured into the recess formed by the annular protrusion 2C and the wall 2D. A resin film 2G as shown in FIG. 3 is placed on the adhesive 2E so as to close the annular window hole 2B. Several notches 2G are provided around the resin film 2G, and the adhesive is exposed at this portion.

  On this resin film 2F, a fixed substrate 3 on which excitation conductor portions 3A and 3a and signal detection conductor portions 3B and 3b, which will be described later, are printed is installed, and the periphery thereof is formed by an adhesive 2E exposed around the resin film 2F. Is fixed to the bottom surface of the case 2A together with the resin film 2F.

  The two rectangular window holes 2H provided in the film 2F are for removing bubbles accumulated between the adhesive 2E, the resin film 2F, and the fixed substrate 3. The resin film 2F has an area that covers at least the excitation conductor portion 3a and the signal detection conductor portion 3b printed on the back surface of the fixed substrate, and an adhesive is provided between the fixed substrate 3 and the resin film 2F between the excitation conductor portion 3a, The distance is managed so as not to flow into the signal detection conductor portion 3b. Alternatively, a groove may be provided in the fixed substrate 3 so as to surround the periphery of the exciting conductor portion 3a, and the groove may be covered with the resin film 2F. If comprised in this way, even if an adhesive approachs from between the fixed board | substrate 3 and the resin film 2F, it will become impossible to reach | attain the excitation conductor part 3a.

  The storage space of the case 2A is covered with a cover plate 2J, and the cover plate 2J is blocked from outside air by bonding the cover plate 2J to the case 2 with an adhesive.

  Terminals 3K1-3K4 molded in the case 2A are electrically connected to the fixed substrate 3.

  As shown in FIG. 1, four annular exciting conductors 3A are printed on a fixed substrate 3 which is an insulating substrate. In addition, a plurality of radially extending signal detection conductors 3B are printed. The same excitation conductor 3A and signal detection conductor 3B are also printed on the back side of the fixed substrate 3, and the front and back excitation conductors 3A and signal detection conductors 3B are connected by through holes 3C-3F.

  In this embodiment, a three-phase AC signal that is 120 degrees out of phase is obtained from the signal detection conductor 3B.

  In addition, two sets of the same non-contact type rotation detection device are formed, and are configured to detect a sensor abnormality by comparing each other's signals and to back up each other in the event of an abnormality.

  3L and 3M are microcomputers, which have drive control and signal processing functions for each non-contact type rotation angle detection device.

  One of the terminals 3K1 to 3K4 functions as a power supply terminal (for example, 3K1), one functions as a ground terminal (for example, 3K3), and the remaining two terminals 3K2 and 3K4 function as signal output terminals of the respective angle detection devices. By arranging the ground terminal between the signal terminals, it is possible to prevent the signal terminals from being short-circuited to cause both signals to be in an abnormal state at the same time.

  The microcomputers 3L and 3M supply current from the power supply terminal 3K1 to the exciting conductor 3A, process the three-phase alternating current waveform generated in the signal detecting conductor 3B, and rotate the disk 1C to which the exciting conductor 1D is attached. As a result, the rotation angle of the rotating shaft 1A is detected.

  The operation of the non-contact type inductance rotation angle detection device of the embodiment will be described below.

  It can be considered that the microcomputer 3M basically controls the conductor pattern groups 3A and 3B constituting the first rotation angle detection device formed on the front and back of FIG.

  On the other hand, it may be considered that the microcomputer 3L basically controls the conductor pattern groups 3A and 3B constituting the second rotation angle detecting device formed on the front and back of FIG. Each of the computers 3L and 3M supplies a direct current Ia from the power supply terminal 3K1 to the exciting conductor 3A.

  When a direct current Ia flows through the exciting conductor 3A, a current IA opposite to the current Ia is applied to the outer circumferential arc-shaped conductor 1D3 of the closed loop type first short ring constituting the exciting conductor 1D of the disk 1C facing the exciting conductor 3A. Excited. This excited current IA flows in the direction of the arrow through each closed loop short ring conductor of the excitation conductor ID. The current IR flowing in the radial conductor 1D1 induces a current Ir in the opposite direction to the current IR in the radial conductor portion of the signal detection conductor 3B facing this portion. This current Ir becomes an alternating current. The short ring 1D9 on the annular base provided at the center is the same as the second short ring-shaped coil A9 of FIGS. 10 and 15 of the previous embodiment, and its function is as described in the embodiment.

  Three sets of phase (U, V, W layer) patterns for the first rotation angle detection device and the second rotation angle detection device by means of 36 signal detection conductors 3B on the front and rear 36 arranged radially at equal intervals. These three sets of phase (U, V, W layer) patterns are formed.

  The AC current Ir is an AC current that is 120 degrees out of phase in each of the U, V, and W layers when the disc 1C is in a specific rotation position, for example, a start position (position where the rotation angle is zero).

  When the disc rotates, the phases of these three-phase alternating currents are shifted from each other. The microcomputers 3L and 3M detect this phase shift, and detect how much the disk 1C has rotated from the phase shift.

  The two signal currents of the first and second rotation angle detection device signals input from the signal detection conductor 3B to the microcomputers 3L and 3M basically have the same value. The microcomputers 3L and 3M process the same signal current, and output signal voltages having the same amount of change and opposite slopes from the signal terminals 3K1 to 3K4. This signal is a signal proportional to the rotation angle of the disk. The external device that has received this signal monitors both signals to determine whether the first and second rotation angle detection devices are normal. If either indicates an abnormality, the remaining detection device signal is used as the control signal.

  Next, an example in which the non-contact rotation angle detection device is applied to a motor-driven throttle valve (throttle valve) control device for a diesel engine will be specifically described with reference to FIGS.

  FIG. 4 is a main sectional view thereof, and FIGS. 5 to 9 are exploded perspective views for explaining the detailed structure.

  The configuration of the motor-driven throttle valve control device will be described below.

  An intake passage 1 (hereinafter referred to as a bore) and a motor housing 20A for housing the motor 20 are molded together in an aluminum die cast throttle valve assembly (hereinafter referred to as a throttle body) 6.

  A metal rotating shaft (hereinafter referred to as a throttle shaft) 3 is disposed on the throttle body 6 along one diameter line of the bore 1. Both ends of the throttle shaft 3 are fitted and fixed to the inner rings of the ball bearings 9 and 10. The outer rings of the ball bearings 9 and 10 are press-fitted and fixed to bearing boss portions 7 and 8 provided on the throttle body 6.

  Thus, the throttle shaft 3 is rotatably supported with respect to the throttle body 6. A throttle valve (hereinafter referred to as a throttle valve) 2 made of a metal disc is inserted into the throttle shaft 3 and is inserted into a slit provided in the throttle shaft 3 and fixed to the throttle shaft 3 with screws 4 and 5. .

  Thus, when the throttle shaft 3 rotates, the throttle valve 2 rotates, and as a result, the cross-sectional area of the intake passage changes and the intake air flow rate to the engine is controlled.

  The motor housing 20A is formed substantially parallel to the throttle shaft 3, and the motor 20 composed of a brush type DC motor is inserted into the motor housing 20A, and the flange of the bracket 20B of the motor 20 is inserted into the side wall 6A of the throttle body 6. The part is fixed by screwing with a screw 21.

  The opening of the bearing boss 8 is sealed with a cap 11, and a seal ring 12 is arranged between the throttle shaft 3 and the inner wall of the bearing boss 9 on the bearing boss 9 side to constitute a shaft seal. Configured to remain confidential.

  As a result, air leakage from the bearing portion or grease for lubricating the bearing is prevented from leaking into the outside air or into a sensor chamber to be described later.

  A metal gear 22 having the smallest number of teeth is fixed to the end of the rotating shaft of the motor 20. A reduction gear mechanism and a spring mechanism for rotationally driving the throttle shaft 3 are collectively arranged on the side surface of the throttle body where the gear 22 is provided. These mechanisms are covered with a resin cover (hereinafter referred to as a gear cover) fixed to the side surface of the throttle body 6. The so-called gear storage chamber 30 covered with the gear cover is provided with the inductance-type non-contact type rotation angle detection device (hereinafter referred to as a throttle sensor) described with reference to FIGS. The angle, and consequently the opening of the throttle valve 2, is detected.

  In the motor-driven throttle valve control device to which the above-described rotation angle detection device is applied, chemical substances such as nitrogen and moisture leaking from the shaft seal 12 to the gear storage chamber 30, adhesion of grease, gear wear powder, etc. In particular, the signal detection conductor and the excitation conductor of the throttle sensor can be protected.

  A throttle gear 13 is fixed to the end of the throttle shaft 3 on the gear storage chamber 30 side. The throttle gear 13 includes a metal plate 14 and a resin gear portion 15 formed by resin molding on the metal plate 14. A cup-shaped recess is provided at the center of the metal plate 14, and a gear-forming flange is provided at the open end of the recess. A resin material gear portion 15 is molded on the flange portion by resin molding.

  The metal plate 14 has a hole in the center of the recess. A screw groove is formed around the tip of the throttle shaft 3. The metal plate 14 is fixed to the throttle shaft 3 by inserting the tip of the throttle shaft 3 into the hole of the concave portion of the metal plate 14 and screwing the nut 17 into the screw portion. Thus, the metal plate 14 and the resin gear portion 15 molded there rotate integrally with the throttle shaft 3.

  A return spring 16 formed of a string-wound spring is sandwiched between the back surface of the throttle gear 13 and the side surface of the throttle body 6 while being compressed in the axial direction. As a result, the throttle shaft 3 is always subjected to a preload in the right direction in FIG. 4, thereby suppressing the shakiness in the axial direction due to the gap of the ball bearing.

  One side of the return spring 16 surrounds the periphery of the bearing boss 7, and its tip is engaged with a notch formed in the throttle body 6, so that the end cannot rotate in the rotational direction. The other end surrounds the cup-shaped portion of the metal plate 14, and its tip is locked in a hole formed in the metal plate 14, so that this end portion cannot rotate in the rotation direction.

  Since the present embodiment relates to a diesel throttle valve control device, the initial position of the throttle valve 2, that is, the throttle valve 2 is set to the initial position when the motor 20 is powered off, and the given opening position is the fully open position. It is.

  For this reason, the return spring 16 is preloaded in the rotational direction so that the throttle valve 2 maintains the fully open position when the motor 20 is not energized.

  Between the gear 22 attached to the rotating shaft of the motor 20 and the gear 25 fixed to the throttle shaft 3, an intermediate is rotatably supported by a metal shaft 24 press-fitted to the side surface of the throttle body 6. The gear 23 is engaged. The intermediate gear 23 includes a large-diameter gear 23A that meshes with the gear 22 and a small-diameter gear 23B that meshes with the throttle gear 13. Both gears are integrally molded by resin molding. These gears 22, 23A, 23B, and 15 constitute a two-stage reduction gear mechanism.

  Thus, the rotation of the motor 20 is transmitted to the throttle shaft 3 through this reduction gear mechanism.

  These speed reduction mechanism and spring mechanism are covered with a gear cover 25 made of a resin material. A groove into which the seal member 32 is inserted is formed at the opening end side periphery of the gear cover 25. When the gear cover 25 is put on the throttle body 6 with the seal member 32 mounted in the groove, the seal member 32 is inserted. Is in close contact with the end face of the frame around the gear housing chamber 30 formed on the side surface of the throttle body 6 to shield the gear housing chamber 30 from the outside air. In this state, the gear cover 25 is fixed to the throttle body 6 with six screws 26.

  The rotation angle detection device, that is, the throttle sensor formed between the reduction gear mechanism configured as described above and the gear cover that covers the reduction gear mechanism will be specifically described below.

  The outer periphery of the cylindrical portion of the resin holder 19 is fixed to the inner peripheral portion of the cup-shaped portion of the throttle gear 13 in the uneven fitting state described above. A disc 18A on which a conductive plate 18 is printed is attached to the flat portion at the tip of the resin holder 19 by adhesion.

  Therefore, when the motor 20 rotates and the throttle valve 2 rotates, the conductive plate 18 also rotates integrally.

  A fixed substrate 27 of the throttle sensor is fixed to the gear cover 25 at a position facing the conductive plate 18 with a film (hereinafter referred to as a thin resin plate) 28 interposed therebetween.

  When a substrate on which the electronic components of the sensor are mounted is disposed in the gear housing chamber 30, the gear housing chamber 30 is exposed to dew condensation caused by wear powder of mechanical components such as gears and air expansion and compression of the gear housing chamber 30.

Furthermore, considering that an electronically controlled throttle body is installed in a diesel engine, sulfur-based chemical substances such as SO ₂ (sulfur dioxide) and S ₈ (sulfur) pass from the bore 1 through the bearing 9 and the seal ring 12 part. There is a possibility that the conductor of the fixed substrate 27 may corrode due to sulfide flowing into the gear storage chamber 30.

  Therefore, in this embodiment, in order to solve the above-described problem, a thin resin plate 28 is provided on the gear cover 25 as shown in FIGS. 4 and 5 to block the substrate mounting space 31 from the gear housing chamber 30.

  A fixed substrate 27 is mounted thereon, and the substrate mounting portion space 31 is covered with a resin cover 29 to shut off the outside air, so that the fixed substrate 27 is airtight with respect to the gear storage chamber 30 and the outside air. It can arrange | position to the space 31 and can overcome the said subject.

  In addition, the gear housing chamber 30 and the substrate mounting portion space 31 are blocked by the thin resin plate 28, so that the clearance between the conductor 18 and the fixed substrate 27 that affects the accuracy of the non-contact type rotational angle detector is larger than necessary. Since the structure does not have to be provided, the tolerance of parts related to the thrust dimension can be made rough, and as a result, a small and inexpensive electronically controlled throttle body can be provided.

  Here, the return spring 16 has a function of pushing the conductive plate 18 to a position close to the thin resin plate 28 and holding the conductive plate 18 so as not to rattle more than necessary in the axial direction. As a result, a small clearance between the conductive plate 18 and the fixed substrate 27 can be maintained over a long period of time, so that it is possible to maintain the accuracy of the non-contact type rotational angle detection device.

  The best mode of the joining structure of the thin resin plate 28 and the fixed substrate 27 by the adhesive is the same as that described with reference to FIGS.

  FIG. 9 shows a plan view of the gear storage chamber 30. The gear storage chamber 30 is partitioned by the frame 6F to which the gear cover 29 is fixed. Six screw holes for screwing the gear cover 29 can be seen inside the frame 6F. 6P1-6P3 are positioning walls for the gear cover 29, and the positioning projections of the gear cover 29 are locked to the three walls, so that the conductor of the fixed substrate 27 is positioned as the rotation-side conductor and is required. A signal within an allowable range can be output. The fully open stopper 13A mechanically determines the initial position (that is, fully open position) of the throttle gear 13, and is constituted by a protrusion formed integrally with the side wall of the throttle body.

  When the notch end portion of the throttle gear 13 abuts on this protrusion, the throttle shaft 3 cannot rotate beyond the fully open position.

  The fully closed stopper 13B regulates the fully closed position of the throttle shaft 3. When the opposite end 13C of the throttle gear 13 collides with the fully closed stopper 13B at the fully closed position, the throttle shaft 3 moves beyond the fully closed position. Stop spinning. Thereby, the maximum value of the position in the rotation direction of the fixed conductor (excitation conductor 18) fixed to the end of the throttle shaft 3 is determined.

  The outputs of the signal detection conductors (corresponding to those indicated by reference numeral 1C in FIG. 2) at the positions of these stoppers indicate fully closed and fully opened values. 20B indicates a motor bracket, and 20F indicates a flange portion of the motor bracket 20B.

The principal part expanded sectional view of an inductance type non-contact-type rotation angle detection apparatus. The principal part disassembled perspective view of an inductance type non-contact-type rotation angle detection device. FIG. 4 is an enlarged plan view of main components of an inductance-type non-contact rotation angle detection device. Sectional drawing of the motor drive type throttle valve control apparatus used for a diesel engine vehicle. The disassembled perspective view of the gear cover of the motor-driven throttle valve control apparatus used for a diesel engine vehicle. 1 is an external perspective view of a motor-driven throttle valve control device used for a diesel engine vehicle. The perspective view which removed the gear cover of the motor drive type throttle valve control apparatus used for a diesel engine vehicle. The throttle body side exploded perspective view of the motor-driven throttle valve control apparatus used for a diesel engine vehicle. The top view of the gear storage chamber of the motor-driven throttle valve control apparatus used for a diesel engine vehicle. The rotor part coil pattern top view of the angle detection sensor of this invention. The assembly drawing of the angle detection sensor of this invention. The top view of the coil pattern of a stator part. The schematic plan view of the coil pattern of a stator part. The output signal waveform diagram from an angle detection sensor. The coil pattern top view of the rotor part and stator part of this invention. Effect explanatory drawing of the angle detection sensor of this invention. The rotor part coil pattern top view which is another Example. The rotor part coil pattern top view of a prior art example. The coil pattern top view of the rotor part and stator part of a prior art example. Explanatory drawing of the angle detection sensor of a prior art example. Explanatory drawing of the angle detection sensor of a prior art example. The rotor part coil pattern top view of a prior art example.

Explanation of symbols

A1 Angle detection sensor A2 Stator printed circuit board A3 Rotating body A4 Printed circuit board A5 Excitation coil A6, A6a, A6b, A6c Detection coil A7 Processing circuit A8a, A8b, A8c, A8d, A8e, A8f First short ring coil A9 Second short ring coil A10 Rotation center axis A11 Excitation coil current direction A12a, A12b, A12c, A12d Short ring coil current direction A13 Excitation coil magnetic field direction A14, A18 Short ring coil magnetic field direction A15, A16, A17 Magnetic flux density distribution curve A20, A21 Short ring coil

Claims (4)

A stator unit having an excitation coil to which a periodic alternating voltage is applied and a plurality of detection coils arranged at predetermined positions in the excitation coil;
It is attached to a rotating shaft that rotates relative to the stator portion, is disposed in a non-contact state in the vicinity of the excitation coil and the plurality of detection coils of the stator portion, and rotates relative to the stator portion. And a rotor part for changing the strength of electromagnetic induction coupling between the coils,
In an angle detection sensor comprising a processing circuit for detecting a relative rotation angle of the rotor portion with respect to the stator portion from output signals of the plurality of detection coils based on a change in strength of the electromagnetic inductive coupling,
In the rotor part,
A plurality of first short ring-shaped coils that are electrically insulated from each other are arranged at specific intervals in the rotation direction of the rotor on the rotor portion that is arranged close to the exciting coil of the stator portion,
The only second short ring coil that is electrically insulated from the plurality of first short ring coils and at least partially close to the plurality of first short ring coils is disposed around the rotation axis. An angle detection sensor.   2. The angle detection sensor according to claim 1, wherein the excitation coil of the stator portion, the plurality of detection coils, and the short ring-shaped coil of the rotor portion are each configured by a printed circuit board circuit. An angle detection sensor. The first short ring-shaped coil is composed of a plurality of closed-loop short ring coils that are subdivided,
The angle is characterized in that the only second short ring-shaped coil is arranged in the first short ring-shaped coil, and is composed of a closed loop type short ring-shaped coil portion in which annular or uneven portions are alternately formed. Detection sensor. The rotating shaft on which the first short ring-shaped coil and the second short ring-shaped coil are formed crosses an intake passage formed in a throttle body;
A rotating throttle valve is fixed to the rotating shaft in the intake passage,
The amount of air flowing through the intake passage is adjusted by the rotation of the throttle valve,
The air flow rate control device for an internal combustion engine comprising the angle detection sensor according to claim 1, wherein the stator portion is provided on a cover portion that covers the rotor portion.

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