Engine throttle device
The throttle device fixes the excitation conductor at a predetermined phase angle using a non-magnetic excitation conductor portion with a rotation restricting mechanism, addressing reliability and cost issues in existing technologies.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MIKUNI CORP
- Filing Date
- 2022-02-04
- Publication Date
- 2026-05-26
AI Technical Summary
Existing throttle devices face issues with unreliable phase angle fixation of the excitation conductor, leading to increased manufacturing costs due to injection molding and complex bending processes, and susceptibility to false detections from heat and vibration.
The throttle device incorporates a non-magnetic excitation conductor portion with a cylindrical portion and a rotation restricting hole and projection, fixed via high-spin crimping, to maintain a predetermined phase angle and prevent rotation, eliminating the need for injection molding and complex bending.
This configuration reduces manufacturing costs, enhances reliability by preventing false detections, and ensures consistent sensor output despite heat and vibration.
Smart Images
Figure 0007865742000001 
Figure 0007865742000002 
Figure 0007865742000003
Abstract
Description
Technical Field
[0001] The present invention relates to a throttle device for an engine.
Background Art
[0002] This type of throttle device is configured by disposing a throttle valve in a throttle bore and supporting it so as to be openable and closable by a throttle shaft, and has a function of adjusting the intake air amount of the engine according to the opening and closing of the throttle valve. For this reason, the opening degree of the throttle valve is used as one of the information for properly operating the engine, and the throttle device is provided with a throttle sensor for detecting the throttle opening degree. For example, an inductive throttle sensor fixes an excitation conductor (target) to the end of the throttle shaft, and an excitation conductor (oscillating coil) and a signal detection conductor (receiving coil) are provided on a circuit board disposed opposite thereto.
[0003] A high-frequency signal is input to the excitation conductor to generate an alternating magnetic field, and the magnetic flux of the magnetic field generated in the signal detection conductor changes due to the mutual induction action to generate a voltage. When the phase angle of the excitation conductor changes integrally with the throttle shaft, the mutual induction action is inhibited accordingly. For example, the voltages of a pair of signal detection conductors change in sine and cosine waves with a 120° period, and based on the voltage ratio (arctan), a sensor output proportional to the phase angle of the excitation conductor, that is, the throttle opening degree, is calculated by an arithmetic circuit. As a throttle device provided with such an inductive throttle sensor, for example, the techniques described in Patent Documents 1 and 2 can be cited. In each patent document, the periphery of the throttle shaft and the excitation conductor is configured as described below.
[0004] In the throttle device of Patent Document 1, the excitation conductor is insert-molded into a synthetic resin holder and a nut is fixed, and this nut is used to fasten the holder together with the driven gear for throttle opening and closing to the end of the throttle shaft.
[0005] Furthermore, in the throttle device described in Patent Document 2, the excitation conductor portion is manufactured by bending a metal plate. The cylindrical press-fit portion of the excitation conductor portion is press-fitted into a cylindrical portion formed on the throttle shaft, and the pair of planar fitting portions of the excitation conductor portion elastically clamps the planar portion formed on the throttle shaft, thereby fixing the excitation conductor portion to the end of the throttle shaft. [Prior art documents] [Patent Documents]
[0006] [Patent Document 1] Patent No. 5064370 [Patent Document 2] Patent No. 5193842 [Overview of the project] [Problems that the invention aims to solve]
[0007] However, the technologies described in Patent Documents 1 and 2 had the following drawbacks. In the technology described in Patent Document 1, the holder into which the excitation conductor is inserted is screw-fastened to the end of the throttle shaft, so the excitation conductor cannot be fixed at the desired phase angle with respect to the throttle valve. As a result, the phase angle of the excitation conductor differs even at the same throttle opening. For example, since the sensor output is calculated to increase from 0V with the inflection point of the output voltage of the signal detection conductor as the origin, if the inflection point is within the range of a throttle opening of slightly less than 90°, a sensor output proportional to the throttle opening cannot be obtained.
[0008] Conventionally, it was necessary to perform operational tests on all throttle sensors, and for those where the inflection point was within the throttle opening range, it was necessary to rewrite the parameters of the calculation circuit to correct the origin. In addition, the technology described in Patent Document 1 requires the injection molding of the holder as one of the manufacturing processes because the excitation conductor is inserted into the holder, and all of these factors contributed to increased manufacturing costs.
[0009] Furthermore, in the technology described in Patent Document 2, the rotation of the throttle shaft is restricted by clamping the flat portion of the throttle shaft with a pair of planar fitting portions of the excitation conductor. However, since this relies on the elasticity of the planar fitting portions, it cannot be said to provide reliable rotation restriction. In addition, the elasticity of the planar fitting portions is not guaranteed to be maintained permanently and may deteriorate due to heat and vibration from the engine to which the throttle device is mounted. There is also a possibility that the planar fitting portions may resonate and break due to vibration. In these cases, the excitation conductor portion cannot be kept at the desired phase angle, and the normal throttle opening detection function cannot be maintained, so there is room for improvement in terms of the reliability of the sensor. In addition, although the technology in Patent Document 2 does not require injection molding of the holder, it is necessary to bend and form the excitation conductor portion, which has a complex shape consisting of a cylindrical press-fit portion and a pair of planar fitting portions, which also contributes to increased manufacturing costs.
[0010] The present invention was made to solve these problems, and its objective is to provide an engine throttle device that can fix the excitation conductor to the throttle valve at a predetermined phase angle, thereby reducing the effort required for writing the calculation circuit, reducing manufacturing costs by eliminating the need for injection molding of the holder supporting the excitation conductor and complex bending of the excitation conductor part, and further improving reliability by preventing false detections caused by heat and vibration. [Means for solving the problem]
[0011] To achieve the above objective, the present invention provides an engine throttle device comprising a throttle valve supported by a throttle shaft within the throttle bore of a throttle body and driven to open and close, an excitation conductor provided at the end of the throttle shaft, and a throttle sensor having a circuit board disposed opposite the excitation conductor and provided with an excitation conductor and a signal detection conductor, wherein the engine throttle device further comprises an excitation conductor portion made of a non-magnetic material and disposed opposite the circuit board, the excitation conductor portion comprising a cylindrical portion along the axis of the throttle shaft, a flat portion extending from the end of the cylindrical portion, a bottom portion opposite the flat portion, and a rotation restricting hole penetrated through the bottom portion, wherein a rotation restricting projection formed at the end of the throttle shaft and the rotation restricting hole of the excitation conductor portion are fitted together, and the rotation restricting projection protrudes into the cylindrical portion of the excitation conductor portion.
[0012] In other embodiments, the planar portion extending from the end of the cylindrical portion of the excitation conductor may extend radially from the end of the cylindrical portion on the circuit board side.
[0013] In other embodiments, the rotation restricting projection may include a fixing portion that restricts the rotation restricting projection from detaching from the rotation restricting hole, and a shaft-side contact surface formed at the end of the throttle shaft and in contact with a sensor-side contact surface formed at the bottom of the excitation conductor portion.
[0014] In other embodiments, the excitation conductor portion may be manufactured by drawing a non-magnetic plate material.
[0015] In other embodiments, the rotation restriction hole and the rotation restriction projection may be shaped in a way other than a single perfect circle to restrict rotation.
[0016] In other embodiments, rotation may be restricted by forming at least one pair of rotation-restricting holes and rotation-restricting protrusions, respectively.
[0017] In another embodiment, the fixing portion may be a crimped portion formed by crimping a rotation-restricting projection.
[0018] As another aspect, the fixing portion may be a welded portion formed by welding the excitation conductor portion to the end portion of the throttle shaft.
[0019] As another aspect, the cylindrical portion may have a cylindrical shape extending while maintaining substantially the same diameter in the axial direction of the throttle shaft.
Advantages of the Invention
[0020] According to the throttle device for an engine of the present invention, the excitation conductor can be fixed to the throttle valve at a desired phase angle, thereby reducing the labor of the writing operation of the arithmetic circuit. In addition, the manufacturing cost can be reduced by eliminating the injection molding of the holder for supporting the excitation conductor and the complicated bending formation of the excitation conductor portion. Furthermore, it is possible to prevent false detection caused by heat and vibration and improve the reliability.
Brief Description of the Drawings
[0021] [Figure 1] It is a perspective view showing the throttle device for an engine of an embodiment. [Figure 2] It is an exploded perspective view in which the sensor unit and the excitation conductor portion are removed from the throttle body. [Figure 3] It is a sectional view taken along line III-III of FIG. 1. [Figure 4] It is a perspective view showing the throttle shaft and the excitation conductor portion. [Figure 5] It is an exploded perspective view showing the throttle shaft and the excitation conductor portion. [Figure 6] It is an exploded perspective view of the throttle shaft and the excitation conductor portion viewed from another direction. [Figure 7] It is a sectional view showing the throttle shaft, the excitation conductor portion, and the circuit board. [Figure 8] It is an exploded perspective view corresponding to FIG. 5 showing another example in which the rotation restricting hole and the rotation restricting projection are square. [Figure 9] It is an exploded perspective view corresponding to FIG. 5 showing another example in which the rotation restricting hole and the rotation restricting projection are hexagonal. [Figure 10]This is an exploded perspective view corresponding to Figure 5, showing another example in which a pair of circular rotation-restricting holes and rotation-restricting protrusions are provided. [Figure 11] This is a cross-sectional view corresponding to Figure 7, showing another example in which the detachment of the rotation-restricting projection from the rotation-restricting hole is restricted by spot welding instead of high-spin crimping. [Modes for carrying out the invention]
[0022] The following describes one embodiment of an engine throttle device embodying the present invention.
[0023] 《Throttle device》 The throttle device 1 of this embodiment is installed on a single-cylinder engine, for example, which is used as a power source for driving a two-wheeled vehicle. First, the configuration of the throttle device 1 will be described. Figure 1 is a perspective view showing the throttle device of the engine in this embodiment, Figure 2 is an exploded perspective view with the sensor unit and excitation conductor removed from the throttle body, and Figure 3 is a cross-sectional view taken along line III-III in Figure 1.
[0024] A single throttle bore 2a, which communicates with the inside of an engine cylinder (not shown), is formed through the throttle body 2 of the throttle device 1, and intake air from an air cleaner (not shown) flows through the throttle bore 2a and is supplied to the inside of the engine cylinder. A throttle valve 3 is supported inside the throttle bore 2a so as to be openable and closable by a throttle shaft 4, and a wire drum 5 is attached to one end of the throttle shaft 4.
[0025] Although not shown in the diagram, the vehicle's throttle grip is connected to the wire drum 5 via a throttle wire. In conjunction with the operation of the throttle grip, the throttle shaft 4 rotates together with the wire drum 5 against the biasing force of the return spring 6, opening and closing the throttle valve 3, thereby adjusting the amount of intake air to the engine. Note that 7 in Figure 3 is the idle speed control valve (ISCV) that controls the engine's idle speed.
[0026] For the sake of explanation, the axial direction along the throttle shaft 4 shown in Figure 1 will be referred to as the left-right direction, the direction of intake air flow along the throttle bore 2a will be referred to as the front-rear direction, and the direction perpendicular to these will be referred to as the up-down direction.
[0027] The left side of the throttle shaft 4 protrudes from the throttle body 2, and a circular recess 2b is formed in the throttle body 2, opening to the left with the throttle shaft 4 as the center, and a mounting surface 2c is formed around the circular recess 2b. As described below, a sensor unit 8 is attached to the mounting surface 2c of the throttle body 2, and the sensor unit 8 is equipped with a throttle sensor 10 along with an intake air temperature sensor and an intake pressure sensor (not shown). The configuration of the throttle sensor 10 will be described in particular with regard to this sensor unit 8.
[0028] Sensor Unit 8 The casing 11 of the sensor unit 8 is injection-molded from a synthetic resin material, with a circular cylindrical portion 11a integrally formed on its right side, and a mounting surface 11b formed around the circular cylindrical portion 11a. A pair of bolt holes 11c are drilled through the casing 11, into which bolts 12 are inserted, and these bolts 12 fasten the casing 11 to the throttle body 2. As shown in Figure 3, in this state, the circular cylindrical portion 11a of the casing 11 fits into the circular recess 2b of the throttle body 2, with the left side of the throttle shaft 4 protruding into the recess, and the mounting surface 11b of the casing 11 overlapping the mounting surface 2c of the throttle body 2.
[0029] The casing 11 has a substrate housing section 11d that opens to the left, and a circuit board 13 is placed inside it. A sealing resin 20 is injected and cured into the substrate housing section 11d by mold filling, thereby sealing the circuit board 13 inside the substrate housing section 11d. During the injection molding of the casing 11, an intake air temperature sensor and an intake pressure sensor are embedded in the casing 11 as insert parts.
[0030] The intake air temperature sensor and intake pressure sensor are not directly related to the gist of the present invention, so only a brief description will be given. The intake air temperature sensor penetrates the throttle body 2, with its tip protruding into the throttle bore 2a, and detects the temperature of the intake air flowing through it. The intake pressure sensor communicates with the inside of the throttle bore 2a via a communication passage formed in the throttle body 2, and detects the pressure of the intake air acting through the communication passage. The detection signals output from each sensor are input to the circuit board 13.
[0031] The throttle sensor 10 consists of an excitation conductor 14 that functions as a target, an excitation conductor 15 that functions as an oscillation coil, a signal detection conductor 16 that functions as a receiving coil, and an IC 17 that functions as an arithmetic circuit, with the IC 17 mounted on a circuit board 13. As will be described in detail later, the excitation conductor 14 is fixed to the left end of the throttle shaft 4 within the circular cylindrical portion 11a of the casing 11.
[0032] The excitation conductor 15 and the signal detection conductor 16 are formed on both sides of the circuit board 13, and the circuit board 13 faces the excitation conductor portion 14 with an air gap of about 1 to 2 mm between them. When the phase angle of the excitation conductor portion 14 changes together with the throttle shaft 4 in response to the opening and closing operation of the throttle valve 3, the output voltage of the signal detection conductor 16 changes accordingly, and based on this output voltage, the IC 17 calculates a sensor output that is proportional to the throttle opening.
[0033] A connector cylinder portion 19a opening towards the rear is integrally formed in the casing 11. Although not shown, terminals of the circuit board 13 are arranged inside the connector cylinder portion 19a to form the connector 19. The sensor unit 8 is mounted on the vehicle's engine with the throttle device 1 attached, and a harness from an ECU (engine control unit) (not shown) provided in the vehicle is connected to the connector 19. Detection signals for throttle opening, intake air temperature, and intake pressure output from the circuit board 13 are input to the ECU via the connector 19 and harness, and the ECU controls the engine's operating state based on these detection signals.
[0034] Next, the details of the excitation conductor section 14 will be described. Figure 4 is a perspective view showing the throttle shaft and the excitation conductor section 14, Figure 5 is an exploded perspective view, Figure 6 is an exploded perspective view from a different direction, and Figure 7 is a cross-sectional view.
[0035] Shape of the excitation conductor section 14 and the left end of the throttle shaft 4 First, we will describe the shape of the excitation conductor portion 14 and the shape of the left end of the throttle shaft 4 to which it is fixed. The excitation conductor portion 14 is integrally manufactured by pressing a plate material with a thickness of approximately 1 mm made of a non-magnetic material, and consists of a cylindrical portion 14a, a target portion 14b, a bottom portion 14c, a sensor-side contact surface 14d, and a rotation restricting hole 14e. Various materials such as SUS, brass, and aluminum can be arbitrarily selected as the non-magnetic plate material. The target portion 14b corresponds to the "flat portion" of the present invention. The cylindrical portion 14a has a diameter slightly smaller than that of the throttle shaft 4 and extends in the direction of the axis L of the throttle shaft 4 while maintaining this diameter.
[0036] The target section 14b is the part that functions as the target and is formed at the end of the cylindrical section 14a on the circuit board 13 side. More specifically, the target section 14b extends radially around the axis L of the throttle shaft 4 and is divided into planar sections at 120° intervals around the axis L, facing the circuit board 13. When the target section 14b rotates, the mutual induction between the excitation conductor 15 and the signal detection conductor 16 is periodically inhibited, causing the output voltage of the signal detection conductor 16 to change. The shape of the target portion 14b is not limited to the above and can be changed as desired. For example, it may be a shape divided at 180° or 90° intervals around the axis L.
[0037] The bottom portion 14c closes the end of the cylindrical portion 14a on the throttle shaft 4 side. The sensor-side contact surface 14d corresponds to the surface of the bottom portion 14c on the throttle shaft 4 side, and as a result, it has a planar shape facing the throttle shaft 4 side. The rotation restricting hole 14e is located through the bottom portion 14c and has a circular shape with flat sides, centered on the axis L of the throttle shaft 4.
[0038] In this embodiment, the excitation conductor portion 14 is manufactured by a drawing process. Since deep drawing is a well-known technique, only a brief outline of the manufacturing procedure for the excitation conductor portion 14 is described below. First, a plate made of a non-magnetic material is used as a blank, and the blank is sandwiched between a die and a blank holder, which have a die hole corresponding to the diameter of the cylindrical portion 14a. When the blank is pushed into the die hole with a punch shaped to correspond to the cylindrical portion 14a and its bottom portion 14c, the cylindrical portion 14a and the bottom portion 14c are drawn and formed, leaving a flange-shaped blank between the die and the blank holder. Next, the flange-shaped portion is punched out with a press to form the desired three-part shape, and the bottom portion 14c of the cylindrical portion 14a is punched out to create a rotation-restricting hole 14e, thereby completing the excitation conductor portion 14.
[0039] On the other hand, a rotation-restricting projection 4a is formed on the axis L at the left end of the throttle shaft 4, and a flat, annular shaft-side contact surface 4b is formed to surround the rotation-restricting projection 4a. The rotation-restricting projection 4a has a shape that allows it to be fitted snugly into the rotation-restricting hole 14e of the excitation conductor portion 14, that is, a cross-sectional shape with flat sides on both sides of a cylinder. The shape of the rotation-restricting hole 14e and the cross-sectional shape of the rotation-restricting projection 4a correspond to the "shape other than a single perfect circle" of the present invention.
[0040] The left end of the throttle shaft 4 is formed, for example, by machining. This is also a well-known technique, so I will not go into detail, but for example, when turning the outer circumference of the throttle shaft 4, the cylinder that will form the base of the rotation-restricting projection 4a and the shaft-side contact surface 4b are formed. Then, when both sides of the cylinder are machined to be flat, the rotation-restricting projection 4a of the desired shape is formed.
[0041] [Status of the excitation conductor portion 14 fixed to the throttle shaft 4] Next, the state in which the excitation conductor portion 14 is fixed to the throttle shaft 4 will be described. The excitation conductor portion 14 is positioned from the left of the left end of the throttle shaft 4, with the rotation restricting hole 14e fitted into the rotation restricting projection 4a of the throttle shaft 4, and the sensor-side contact surface 14d in contact with the shaft-side contact surface 4b. The fitting of the rotation restricting hole 14e and the rotation restricting projection 4a restricts the rotation of the excitation conductor portion 14 relative to the throttle shaft 4.
[0042] The tip of the rotation-restricting projection 4a is crimped with high-spin crimping and flattened, and the crimped portion 4c formed thereby restricts the detachment of the rotation-restricting projection 4a from the rotation-restricting hole 14e, thereby maintaining the contact state between the sensor-side contact surface 14d and the shaft-side contact surface 4b. As a result, the excitation conductor portion 14 is fixed to the left end of the throttle shaft 4, and the excitation conductor portion 14 is maintained at the desired phase angle with respect to the phase angle of the throttle shaft 4, in other words, the opening degree of the throttle valve 3. High-spin crimping corresponds to the "crimping process" of the present invention, and the crimped portion 4c corresponds to the "fixing portion" of the present invention.
[0043] Comparison with the technologies described in Patent Documents 1 and 2 The throttle device 1 of this embodiment, configured as described above, resolves the problems of the technologies described in Patent Documents 1 and 2, which will be explained in detail below. First, in the technology described in Patent Document 1, it was required to write the calculation contents into the calculation circuit so that a sensor output with a desired relationship to the throttle opening could be obtained. This was because the phase angle of the excitation conductor of the holder screw-fastened to the end of the throttle shaft was not fixed.
[0044] In contrast, in this embodiment, the engagement of the rotation restricting hole 14e and the rotation restricting projection 4a maintains the excitation conductor portion 14 at a predetermined phase angle with respect to the phase angle of the throttle shaft 4. Therefore, by writing a common parameter based on this phase angle to the IC 17, a sensor output proportional to the throttle opening can be obtained for any throttle sensor 10. Consequently, the operational testing of all throttle sensors and the rewriting of the calculation circuit parameters, which were carried out in the technology of Patent Document 1, become unnecessary, thus reducing the manufacturing cost of the throttle sensor 10 and, consequently, the manufacturing cost of the throttle device 1.
[0045] Furthermore, the technology described in Patent Document 1 requires an injection molding process to support the excitation conductor, and the technology described in Patent Document 2 requires a bending process to form the excitation conductor portion, both of which contribute to increased manufacturing costs. In contrast, in this embodiment, the excitation conductor portion 14 is formed by drawing, so it can be manufactured by a simple operation as illustrated above. In addition, fixing to the throttle shaft 4 can be completed by simply fitting the rotation restricting hole 14e of the excitation conductor portion 14 into the rotation restricting projection 4a and performing high-spin crimping, and these factors also contribute to reducing manufacturing costs.
[0046] This point will be explained in more detail. In the direction of the axis L of the throttle shaft 4, the following conditions are required for the positional relationship between the circuit board 13, the target unit 14b, and the throttle shaft 4. It is desirable that the circuit board 13 and the target unit 14b be positioned as close together as possible while preventing contact between them. The further the target unit 14b is from the excitation conductor 15 on the circuit board 13, the stronger the AC magnetic field of the excitation conductor 15 needs to be to obtain a normal mutual induction effect. This is because it would lead to problems such as an increase in the power consumption of the excitation conductor 15 and an increase in noise affecting peripheral equipment.
[0047] Furthermore, it is desirable to position the circuit board 13 and the throttle shaft 4 as far apart as possible. This is because if the throttle shaft 4, which is made of magnetic material, approaches the circuit board 13, the alternating magnetic field generated by the excitation conductor 15 will be affected, causing detection errors. As a result, it is necessary to satisfy the conflicting conditions of reducing dimension A1 in Figure 7 to bring the target portion 14b closer to the circuit board 13, and increasing dimension A2 to move the throttle shaft 4 further away.
[0048] Although the holder in Patent Document 1 not only supports the excited conductor but also plays a role in separating the excited conductor from the end of the throttle shaft, as mentioned above, the manufacturing of the holder is a factor that increases costs.
[0049] In contrast, in the excitation conductor section 14 of this embodiment, the target section 14b and the sensor-side contact surface 14d are spaced apart in the direction of the axis L of the throttle shaft 4 via the cylindrical section 14a. The sensor-side contact surface 14d is fixed to the left end of the throttle shaft 4, and the target section 14b faces the circuit board 13 via an air gap. As a result, the target section 14b is close to the circuit board 13, eliminating the need to excessively strengthen the AC magnetic field of the excitation conductor 15. Furthermore, since the throttle shaft 4, made of magnetic material, is spaced apart from the circuit board 13, the influence of the AC magnetic field on the excitation conductor 15 can be prevented. In other words, since the cylindrical section 14a of the excitation conductor section 14 performs the function of the holder in Patent Document 1, it is possible to prevent the increase in manufacturing costs caused by the production of the holder.
[0050] In this embodiment, the rotation-restricting projection 4a of the throttle shaft 4 is made to protrude into the cylindrical portion 14a of the excitation conductor portion 14 in order to perform high-spin crimping, so the throttle shaft 4 is closer to the circuit board 13 by the amount of this protrusion. However, since the length of the cylindrical portion 14a in the axial direction L is set taking into account the protrusion of this rotation-restricting projection 4a, it is possible to reliably prevent the influence of the AC magnetic field on the excitation conductor 15.
[0051] Furthermore, in the technology described in Patent Document 2, the excitation conductor portion is restricted from rotating relative to the throttle shaft, thereby determining the phase angle. However, as described above, the complex shape of the excitation conductor portion contributes to increased costs. In contrast, the excitation conductor portion 14 of this embodiment has a simple shape, connecting the target portion 14b and the sensor-side contact surface 14d via a cylindrical portion 14a, and therefore, drawing can be applied to its manufacture. Drawing allows for the manufacture of an excitation conductor portion 14 of the desired shape from a single sheet of material, and the cylindrical portion 14a is formed simultaneously with other parts such as the target portion 14b. As a result, the manufacturing process is simpler compared to the excitation conductor portion of Patent Document 2, preventing increased manufacturing costs.
[0052] In particular, the cylindrical portion 14a of the excitation conductor portion 14 in this embodiment is cylindrical in shape, extending in the axial direction L of the throttle shaft 4 while maintaining a substantially constant diameter. The sensor-side contact surface 14d at the right end of the cylindrical portion 14a requires a certain area for contact with the axial-side contact surface 4b of the throttle shaft 4, and it is desirable to reduce the inner diameter of the target portion 14b at the left end of the cylindrical portion 14a in order to secure an area that can inhibit mutual induction. On the other hand, in order for the drawing process to work, the left end of the cylindrical portion 14a cannot have a smaller diameter than the right end. If the cylindrical portion 14a has a substantially constant diameter in the axial direction L, an excitation conductor portion 14 with a shape suitable for any condition can be manufactured by drawing.
[0053] However, the excitation conductor portion 14 of the present invention is not limited to being manufactured by deep drawing, and may be manufactured by other processing techniques, such as machining. Even in this case, the excitation conductor portion 14 can be easily manufactured because of its simple shape.
[0054] On the other hand, in the technology described in Patent Document 2, the planar portion of the throttle shaft is sandwiched between a pair of planar fitting portions to restrict the rotation of the excitation conductor portion. However, this relies on the elasticity of the planar fitting portions, and there is a possibility that the elasticity may deteriorate due to heat or vibration, or that the planar fitting portions may resonate and break when subjected to vibration.
[0055] In contrast, the excitation conductor portion 14 of this embodiment restricts the rotation of the excitation conductor portion 14 by fitting the rotation restricting hole 14e with the rotation restricting projection 4a, and the crimping portion 4c restricts the detachment of the rotation restricting projection 4a from the rotation restricting hole 14e. With this connection structure, deterioration and resonance do not occur even when subjected to heat and vibration, so the excitation conductor portion 14 can be reliably maintained at the desired phase angle with respect to the phase angle of the throttle shaft 4. As a result, erroneous detection of throttle opening can be prevented, and the reliability of the sensor can be improved.
[0056] The embodiments of the present invention are not limited to this embodiment. For example, in the above embodiment, it is embodied in a throttle sensor 10 of a throttle device 1 equipped with a single throttle bore 2a mounted on a single-cylinder two-wheeled vehicle, but the target vehicle and type of throttle device 1 are not limited thereto, and for example, it may be applied to a four-wheeled vehicle. Alternatively, it may be applied to small two-wheeled vehicles such as scooters and mopeds, larger two-wheeled vehicles, or saddle-type vehicles such as ATVs (All Terrain Vehicles) such as four-wheeled buggies. Furthermore, it may be applied to throttle devices of engines used for purposes other than as a power source for driving, for example, generator engines. Moreover, it may be applied to multi-throttle devices equipped with multiple throttle bores.
[0057] Furthermore, although the above embodiment is embodied in a throttle device 1 that mechanically opens and closes the throttle valve 3 via a throttle wire in response to the operation of the throttle grip, it is not limited to this. For example, it may be embodied in an electronically controlled throttle device that drives the opening and closing of the throttle valve by a motor.
[0058] Furthermore, in the above embodiment, an intake air temperature sensor and an intake pressure sensor were provided in addition to the throttle sensor 10 as sensors, but this is not the only option. For example, only the throttle sensor 10 may be provided, or other sensors may be added. In the above embodiment, the rotation restricting hole 14e is made into a circular hole with flat sides, and the rotation restricting projection 4a is made into a cylindrical shape with flat sides, and the rotation restricting conductor portion 14 is restricted from rotating by fitting them together. However, rotation can be restricted with any shape other than a single perfect circle. For example, as shown in Figure 8, a square rotation restricting hole 21 may be fitted with a rotation restricting projection 22 with a square cross-section, or as shown in Figure 9, a hexagonal rotation restricting hole 31 may be fitted with a rotation restricting projection 32 with a hexagonal cross-section.
[0059] Furthermore, multiple rotation-restricting holes and multiple rotation-restricting protrusions may be fitted together, in which case rotation restriction is possible even with a perfectly circular cross-section. For example, as shown in Figure 10, a pair of perfectly circular rotation-restricting holes 41 may be provided through the bottom 14c of the excitation conductor portion 14, and a pair of rotation-restricting protrusions 42 with a perfectly circular cross-section may be formed at the left end of the throttle shaft 4, and these may be fitted together.
[0060] In the above embodiment, a crimped portion 4c is formed as a fixed portion by high-spin crimping to prevent the rotation restricting projection 4a from detaching from the rotation restricting hole 14e. However, other methods may be applied if detachment prevention is possible. For example, as shown in Figure 11, the axial contact surface 4b of the throttle shaft 4 and the bottom portion 14c of the excitation conductor portion 14 may be joined by spot welding, and detachment may be prevented by the spot welded portion 51 formed thereby. In this case, the spot welded portion 51 corresponds to the "fixed portion" of the present invention.
[0061] Furthermore, in Figure 11, the rotation restricting hole 14e and the rotation restricting projection 4a are offset from the axis L of the throttle shaft 4 in order to secure space for spot welding on the bottom portion 14c. However, since no problem arises as long as the excitation conductor portion 14 can be fixed in the normal position on the axis L, the rotation restricting hole 14e and the rotation restricting projection 4a, which are offset from the axis L in this manner, are also included in the invention.
[0062] On the other hand, as described above, in the above embodiment, a unique effect is obtained by making the cylindrical portion 14a of the excitation conductor portion 14 a cylindrical shape with substantially the same diameter, but it is not limited to this. For example, in the other example shown in Figure 11, the cylindrical portion 14a may be shaped to widen towards the circuit board 13 in order to facilitate insertion of the spot welding electrode into the cylindrical portion 14a. [Explanation of Symbols]
[0063] 1. Throttle device 2 Throttle Body 2a Throttle bore 3. Throttle valve 4 Throttle shaft 4a, 22, 32, 42 Rotation restricting protrusions 4b Shaft side contact surface 4c Crimping part (fastening part) 10 Throttle Sensor 13 Circuit board 14 Excited Conductor Section 14a Cylinder part 14b Target section (flat section) 14c bottom 14d Sensor-side contact surface 14e, 21, 31, 41 Rotation regulating holes 15 Excitation Conductor 16 Signal detection conductor 17 IC 51 Welded joint (fixed joint)
Claims
1. In an engine throttle device comprising a throttle valve supported by a throttle shaft within the throttle bore of a throttle body and driven to open and close, an excitation conductor provided at the end of the throttle shaft, and a throttle sensor having a circuit board disposed opposite the excitation conductor and provided with an excitation conductor and a signal detection conductor, It further comprises an excitation conductor portion formed of a non-magnetic material and arranged opposite to the circuit board, The excitation conductor portion comprises a cylindrical portion along the axis of the throttle shaft, a flat portion extending from the end of the cylindrical portion, a bottom portion facing the flat portion, and a rotation restricting hole provided through the bottom portion. The rotation-restricting projection formed at the end of the throttle shaft and the rotation-restricting hole of the excitation conductor are fitted together, and the rotation-restricting projection protrudes into the cylindrical portion of the excitation conductor. An engine throttle device characterized by the following:
2. The throttle device for an engine according to claim 1, characterized in that the planar portion extending from the end of the cylindrical portion of the excitation conductor portion extends radially from the end of the cylindrical portion on the circuit board side.
3. The rotation-restricting projection includes a fixing portion that restricts the rotation-restricting projection from detaching from the rotation-restricting hole, The throttle device for an engine according to claim 1, comprising: a shaft-side contact surface formed at the end of the throttle shaft and in contact with a sensor-side contact surface formed at the bottom of the excitation conductor portion.
4. The excitation conductor portion is manufactured by drawing a non-magnetic plate material. The throttle device for an engine according to feature 1.
5. The rotation-restricting hole and the rotation-restricting projection are restricted from rotating by having a shape other than a single perfect circle. The throttle device for an engine according to feature 1 or 4.
6. The rotation restricting holes and rotation restricting protrusions are formed in pairs, respectively, thereby restricting rotation. The throttle device for an engine according to feature 1 or 4.
7. The fixing portion is a crimped portion formed by crimping the rotation-restricting projection. The throttle device for an engine according to feature 3.
8. The aforementioned fixing portion is a welded portion formed by welding the excitation conductor portion to the end of the throttle shaft. The throttle device for an engine according to feature 3.
9. The cylindrical portion has a cylindrical shape that extends in the axial direction of the throttle shaft while maintaining substantially the same diameter. The throttle device for an engine according to any one of claims 1 to 8, characterized by the features described herein.