Throttling device for an engine

Abstract

The throttle device of the present application can reduce the space occupied in the axial direction of the throttle valve to achieve compactness. The throttle device includes: a throttle device main body that supports a throttle valve via a throttle valve shaft in a throttle hole; a gear cover that divides a gear housing chamber with the throttle device main body; a gear train that is housed in the gear housing chamber and is composed of at least a driven gear fixed to the throttle valve shaft and a driving gear; a motor that has the driving gear fixed to an output shaft and opens and closes the throttle valve; an intake temperature sensor that is provided on the gear cover, penetrates the gear housing chamber, and has a front end protruding into the throttle hole to detect the intake temperature; and an intake pressure sensor that is provided on the gear cover, penetrates the gear housing chamber via a pressure passage, and detects the intake pressure in the throttle hole. The driven gear is formed with a clearance portion that prevents interference with each sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to a throttle device of an engine. BACKGROUND

[0002] For example, Patent Literature 1 discloses a throttle device for a single-cylinder engine, in which a throttle valve is supported by a throttle valve shaft so as to be openable and closable within a single throttle hole formed in a throttle device main body. The throttle valve shaft protrudes from the throttle hole toward one side, and a recess is integrally formed in the throttle device main body in a manner of surrounding an end portion of the throttle valve shaft, and the recess is closed from the one side by a cover member, thereby dividing a gear housing chamber. A motor is installed at the throttle device main body in a posture in which an output shaft protrudes into the gear housing chamber, and rotation of the output shaft is transmitted to the throttle valve shaft via a gear train, and the amount of intake air flowing within the throttle hole is adjusted according to opening and closing of the throttle valve.

[0003] A sensor unit including an intake air temperature sensor and an intake air pressure sensor is installed at the other side of the throttle device main body, in other words, at the side opposite to the gear housing chamber with the throttle device main body interposed therebetween. In detail, the intake air temperature sensor protrudes from the sensor unit, and a front end thereof protrudes into the throttle hole through the throttle device main body, and detects the temperature of intake air flowing within the throttle hole. Further, a pressure passage is formed at the throttle device main body, and the intake air pressure sensor communicates with the throttle hole via the pressure passage, and detects the pressure of intake air flowing within the interior.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Laid-Open No. 2019-132202 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Such a throttle device is mounted to a vehicle in a state of being installed to an engine, and therefore, in order to prevent interference with auxiliary equipment classes and the like of the engine, compactness is required.

[0009] For example, the throttle device for a single-cylinder engine described in Patent Literature 1 is mounted to a bicycle with a prime mover and the like having a small vehicle body, and in the vicinity thereof, not only auxiliary equipment classes of the engine but also a fuel tank, a vehicle body frame, and the like are provided, and therefore, compactness is particularly required.

[0010] In the throttle device described in Patent Literature 1, in addition to the throttle device main body that functions to regulate the amount of intake air, a gear housing chamber in which a gear train is housed is partitioned on one side of the throttle device main body, and a sensor unit including an intake air temperature sensor and an intake air pressure sensor is attached to the other side. As a result, the space occupied by the entire throttle device in the throttle valve axis direction increases, and therefore a countermeasure for compactness has been required in the past.

[0011] The present application has been made to solve the above problems, and has an object to provide a throttle device of an engine that can reduce the space occupied in the throttle valve axis direction to achieve compactness.

[0012] Technical Solution for Solving Technical Problem

[0013] To achieve the above object, a throttle device of an engine according to the present application includes: a throttle device main body that is formed with a throttle hole that communicates with a cylinder in a state of being attached to an engine, a throttle valve that is supported by a throttle valve shaft to be opened and closed in the throttle hole, and the throttle valve shaft that protrudes from an outer side toward one side; a gear cover that closes an outer side of the throttle device main body from the one side and partitions a gear housing chamber; a gear train that is housed in the gear housing chamber and is constituted at least by a driven gear that is fixed to the throttle valve shaft and a drive gear that transmits rotation to the driven gear; a motor that is attached to the throttle device main body, the drive gear is fixed to an output shaft that protrudes into the gear housing chamber, and the throttle valve is opened and closed via the gear train to regulate the amount of intake air that flows in the throttle hole; an intake air temperature sensor that is provided to the gear cover, protrudes a front end into the throttle hole of the throttle device main body, and detects the temperature of intake air that flows in the throttle hole; and an intake air pressure sensor that is provided to the gear cover, communicates with the throttle hole of the throttle device main body via a pressure passage, and detects the pressure of intake air that flows in the throttle hole, at least either one of the intake air temperature sensor and the pressure passage is disposed at a position overlapping the driven gear in a direction along the throttle valve shaft and is disposed so as to extend toward the throttle hole through the gear housing chamber, a through groove in a circular arc shape is formed in a path along which at least either one of the intake air temperature sensor and the pressure passage relatively moves in conjunction with rotation of the driven gear at the driven gear, and at least either one of the intake air temperature sensor and the pressure passage is inserted into the through groove and is prevented from interfering with the driven gear (Technical Solution 1).

[0014] As other modes, it can also be that an intermediate gear is provided between the drive gear and the driven gear, the intermediate gear is composed of a large-diameter portion that meshes with the drive gear and a small-diameter portion that meshes with the driven gear, and at least either one of the intake temperature sensor and the pressure passage is disposed at a position that avoids an area where the large-diameter portion of the intermediate gear and the driven gear overlap, as viewed in the direction along the throttle shaft (Technical Solution 2).

[0015] As other modes, it can also be that the pressure passage is integrally formed in the gear cover and is tubular, penetrates the gear housing chamber, and opens the front end in the throttle hole via a through hole formed in the throttle device main body (Technical Solution 3).

[0016] As other modes, it can also be that the intake temperature sensor and the pressure passage are respectively disposed at positions that overlap the driven gear, as viewed in the direction along the throttle shaft, and penetrate the gear housing chamber, and through grooves that respectively prevent interference with the intake temperature sensor and the pressure passage are formed at the driven gear (Technical Solution 4).

[0017] As other modes, it can also be that the intake temperature sensor is disposed at a position that is upstream of the throttle valve in the intake flow direction in the throttle hole, and the intake pressure sensor and the pressure passage are disposed at positions that are downstream of the throttle valve in the intake flow direction in the throttle hole (Technical Solution 5).

[0018] As other modes, it can also be that a throttle opening degree sensor that detects the throttle opening degree is provided at a position on the axis of the throttle shaft of the gear cover, and the intake temperature sensor and the intake pressure sensor are disposed at a region around the throttle opening degree sensor on the gear cover (Technical Solution 6).

[0019] As other modes, it can also be that the throttle device main body is formed with a single throttle hole, and is mounted to a single-cylinder engine that is installed as a traveling power source in a straddle-type vehicle (Technical Solution 7).

[0020] The throttle device of the engine according to the present application can achieve compactness by reducing the occupied space in the direction of the throttle axis. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a perspective view of a throttle device of an embodiment.

[0022] Figure 2 is a perspective view of a throttle device main body of the first embodiment with a gear cover removed to show a gear train in a gear housing chamber.

[0023] Figure 3 is a perspective view of the throttle device main body with the gear cover removed to show an inner side surface of the gear cover.

[0024] Figure 4is an exploded perspective view showing the relationship of the motor, gear train, and throttle valve shaft.

[0025] Figure 5 is a view showing the configuration of the gear train and each sensor in the gear housing chamber when the throttle valve is fully closed.

[0026] Figure 6 is a view showing the relationship of the motor, gear train, and throttle valve shaft and the throttle opening sensor, Figure 5 a VI-VI sectional view of Fig.

[0027] Figure 7 is a VII-VII sectional view of Fig. Figure 5 a VII-VII sectional view of Fig.

[0028] Figure 8 is a VIII-VIII sectional view of Fig. Figure 5 a VIII-VIII sectional view of Fig.

[0029] Figure 9 is a view showing the gear train in the gear housing chamber when the throttle valve is fully open.

[0030] Figure 10 is a perspective view showing the gear train in the gear housing chamber when the throttle valve is fully open.

[0031] Figure 11 is a view showing the gear train in the gear housing chamber when the throttle valve is fully closed.

[0032] Figure 12 is a view showing the gear train in the gear housing chamber when the throttle valve is fully open.

[0033] (Symbol Explanation)

[0034] 1 throttle device

[0035] 2 throttle hole

[0036] 3 throttle valve shaft

[0037] 4 throttle valve

[0038] 5 throttle device body

[0039] 6 gear housing chamber

[0040] 7 gear cover

[0041] 8 gear train

[0042] 9 motor

[0043] 9a output shaft

[0044] 16 drive gear

[0045] 17 intermediate gear

[0046] 17a large diameter portion

[0047] 17b small diameter portion

[0048] 18 driven gear

[0049] 21 throttle opening sensor

[0050] 22 intake air temperature sensor

[0051] 23 intake air pressure sensor

[0052] 37 pressure passage

[0053] 39 through hole

[0054] 41 first through groove (avoidance portion)

[0055] 42 second through groove (avoidance portion) DETAILED DESCRIPTION

[0056] Hereinafter, an embodiment in which the present application is embodied as a throttle device for a single cylinder engine mounted on a bicycle with a prime mover as a traveling power source will be described.

[0057] The throttle device 1 is mounted on an engine not shown, and functions to adjust the amount of intake air supplied to the cylinder of the engine in accordance with the throttle operation by the driver. As shown in Figures 1-3 , the throttle device 1 is composed of, as a whole, a throttle device main body 5 in which a throttle valve 4 is supported so as to be opened and closed by a throttle valve shaft 3 in a single throttle hole 2 communicating with the cylinder of the engine, a gear cover 7 which divides a gear housing chamber 6 between the throttle device main body 5, and a motor 9 which transmits the rotation of an output shaft 9a protruding into the gear housing chamber 6 to the throttle valve shaft 3 via a gear train 8 to open and close the throttle valve 4.

[0058] The throttle device 1 of the present embodiment is mounted on a vehicle in the posture shown in Figure 1 . According to this posture, in the following description, the intake air flow passage direction along the axis Cb of the throttle hole 2 will be referred to as the front-rear direction, the throttle valve axis direction along the axis Cth of the throttle valve shaft 3 orthogonal to the front-rear direction will be referred to as the left-right direction, and the gear train direction in which the gear train 8 is arranged orthogonal to both of the above directions will be referred to as the up-down direction. Of course, the mounting posture of the throttle device 1 is not limited to this, and can be changed to various postures.

[0059] (throttle device main body 5)

[0060] As shown in Figure 4 , 6A throttle orifice 2 is provided through the main body 5 of the throttle device in the front-rear direction, and a motor housing chamber 10 for housing the motor 9 is integrally formed adjacent to the lower part of the throttle orifice 2. The main body 5 of the throttle device is connected to the intake manifold of the engine via a flange 11 formed at the rear end of the throttle orifice 2 by bolts (not shown). An air filter (not shown) is connected to the front end of the throttle orifice 2. The throttle valve shaft 3 is disposed in the main body 5 of the throttle device through the throttle orifice 2 and is supported by a pair of bearings 12 to be rotatable. Inside the throttle orifice 2, the throttle valve 4 is fixed to the throttle valve shaft 3 by a pair of small screws 13. During engine operation, the throttle valve 4 opens and closes with the rotation of the throttle valve shaft 3 to regulate the amount of intake air flowing in the throttle orifice 2.

[0061] (Gear Reception Chamber 6)

[0062] The throttle valve shaft 3 extends to the right within the throttle device body 5, with its end protruding outward from the right side of the throttle device body 5. A recess 14 opening to the right is formed on the entire right side of the throttle device body 5. The end of the throttle valve shaft 3 is surrounded by the recess 14, and the output shaft 9a of the motor 9 also protrudes into the recess 14. The recess 14 corresponds to the outer surface of the throttle device body of the present invention.

[0063] A gear cover 7 with a left-facing opening is disposed in the recess 14 of the throttling device body 5. The gear cover 7 overlaps with the periphery of the recess 14 via a seal (not shown) and is fastened by four small screws 15. The recess 14 is closed by the gear cover 7, and a gear receiving chamber 6 extending in the vertical direction is divided between the gear cover 7 and the recess 14.

[0064] like Figures 4-6 As shown, a gear train 8 is provided between the output shaft 9a of the motor 9 and the throttle valve shaft 3 within the gear housing 6. The gear train 8 consists of a drive gear 16 fixed to the output shaft 9a of the motor 9, a driven gear 18 fixed to the throttle valve shaft 3, and an intermediate gear 17 located between the drive gear 16 and the driven gear 18. The gears 16-18 are arranged side-by-side in the vertical direction. The intermediate gear 17 is rotatably supported by a gear shaft 19 erected between the throttle device body 5 and the gear cover 7, and integrally forms a large-diameter portion 7a that meshes with the drive gear 16 and a small-diameter portion 17b that meshes with the driven gear 18. Inside the gear housing 6, a return spring 20 is wound around the throttle valve shaft 3. Although not shown, one end of the spring is hooked to the side of the throttle device body 5, and the other end is hooked to the throttle valve shaft 3.

[0065] The throttle valve 4 is urged toward a predetermined opening degree, for example, a fully closed position, and the like by the force of the return spring 20. Further, when the motor 9 is operated, the rotation of the output shaft 9a is transmitted to the large-diameter portion 17a of the intermediate gear 17 while being decelerated, and further transmitted to the driven gear 18 from the small-diameter portion 17b of the intermediate gear 17 while being decelerated, and the throttle valve shaft 3 is rotated against the force of the return spring 20 to open and close the throttle valve 4 as described above.

[0066] In addition, the structure of the gear train 8 is not limited to this, and the number of gears, the arrangement of the gears, and the like can be arbitrarily changed as long as the rotation of the output shaft 9a of the motor 9 is transmitted to the throttle valve shaft 3 while being decelerated.

[0067] As described above, in the throttle device 1 of the present embodiment, in addition to the throttle device main body 5 that originally functions to adjust the intake air amount, the gear housing chamber 6 that houses the gear train 8 for motor driving is provided on the right side thereof, and this is the same as the technology of Patent Document 1. Further, in order to control the engine, the throttle device 1 includes an intake air temperature sensor that detects the temperature of the intake air flowing in the throttle hole 2 and an intake air pressure sensor that detects the pressure of the intake air, and this is also the same as Patent Document 1. Therefore, assuming that each of the sensors is mounted on the left side of the throttle device main body 5, in other words, on the side opposite to the gear housing chamber 6 sandwiching the throttle device main body 5, as described in the "Technical Problem to be Solved by the Invention", there is a problem that the occupied space of the throttle device 1 in the left-right direction increases.

[0068] In view of the above-described problems, the present inventors focused on the gear cover 7 that divides the gear housing chamber 6 from the throttle device main body 5. Such a motor-driven throttle device 1 sometimes includes a throttle opening degree sensor, and in the present embodiment, a magnetic throttle opening degree sensor 21 is housed in the gear housing chamber 6 together with the gear train 8. In order to detect the rotation angle of the throttle valve shaft 3 as the throttle opening degree, the throttle opening degree sensor 21 is arranged at a position on the throttle shaft line Cth in the gear housing chamber 6 in a posture opposite to the driven gear 18 as shown in FIG. 6. Figure 6

[0069] As a result, the throttle opening degree sensor 21 is arranged between the driven gear 18 and the inner side surface of the gear cover 7, and in order to secure the installation space thereof, the gear cover 7 originally has a cross-sectional shape that is separated to the right from the driven gear 18. Therefore, on the gear cover 7, in particular, a dead zone is formed around the throttle opening degree sensor 21, and there is a margin in which the intake air temperature sensor and the intake air pressure sensor can be arranged.

[0070] ​According to the above-described insight, in the present embodiment, the intake air temperature sensor 22 and the intake air pressure sensor 23 are provided together with the throttle opening degree sensor 21 at the gear cover 7, achieving compactness. In order to detect the intake air temperature, it is necessary to extend the intake air temperature sensor 22 from the gear cover 7 toward the throttle device main body 5 side and project the front end thereof into the throttle hole 2. In addition, in order to detect the intake air pressure, it is necessary to communicate the intake air pressure sensor 23 and the throttle hole 2 via the pressure passage 37 described later. Therefore, the above-described intake air temperature sensor 22 and the pressure passage 37 are arranged so as to penetrate the gear housing chamber 6 between the gear cover 7 and the throttle device main body 5, but it is necessary to prevent them from interfering with the gear train 8 housed in the gear housing chamber 6. However, when the positions of the intake air temperature sensor 22 and the pressure passage 37 are changed in order to prevent interference, various disadvantages such as, for example, the respective sensors 22, 23 and the throttle hole 2 being arranged offset from the original appropriate positions, or the throttle device 1 being upsized, etc. can result.

[0071] In view of the new technical problem of preventing interference with the gear train 8 as described above, the present inventors focused on the driven gear 18 connected to the throttle shaft 3. The rotational angles of the respective gears 16 to 18 when the throttle valve 4 is opened and closed between full opening and full closing by rotation transmission accompanying deceleration in the gear train 8 as described above satisfy the relationship of drive gear 16 > intermediate gear 17 > driven gear 18. The rotational angles of the other gears 16, 17 are 360° or more, and in contrast, the rotational angle of the driven gear 18 is less than 90° corresponding to the required opening and closing angle of the butterfly throttle valve 4.

[0072] Therefore, if the avoidance portion is formed in the driven gear 18 in a region slightly wider than 90° centered on the throttle shaft 3, and the intake air temperature sensor 22 and the pressure passage 37 are arranged so as to penetrate the avoidance portion, interference of the driven gear 18 with the intake air temperature sensor 22 and the pressure passage 37 can be prevented on the basis of allowing the driven gear 18 to rotate. If it is the other gears 16, 17 having a rotational angle of 360° or more, interference cannot be prevented by the avoidance portion as described above. In addition, in order to arrange the intake air temperature sensor 22 and the pressure passage 37 so as to penetrate the avoidance portion formed at the driven gear 18, it is desirable to arrange the respective sensors 22, 23 at positions overlapping the driven gear 18 when viewed from the right, i.e., when viewed from the "direction along the throttle shaft" of the present application, since such an arrangement means that the respective sensors 22, 23 are arranged in the periphery of the throttle opening degree sensor 21, and is therefore also preferable from the aspect of effective use of dead space.

[0073] Based on the above insights, in this embodiment, the intake air temperature sensor 22 and the intake air pressure sensor 23 are provided together at the gear cover 7 and the throttle valve opening sensor 21, and a clearance portion is formed at the driven gear 18 to prevent interference with the intake air temperature sensor 22 and the pressure passage 37. As a clearance portion, through slots 41 and 42 are formed in the first embodiment, and a notch 51 is formed in the second embodiment. Before describing each embodiment, the structurally common parts will be described first.

[0074] (The overall structure of gear cover 7)

[0075] like Figure 2 , Figure 3 As shown, the gear cover 7 is manufactured by injection molding of synthetic resin material. The substrate 26, sensors 21-23, and terminals 27 and 28 are embedded in the gear cover 7 through insert molding. Furthermore, although in Figure 2 , Figure 3 The diagram shows the substrate 26 and terminals 27, 28 separated from the gear cover 7, but they are actually embedded in the gear cover 7 during injection molding. This is shown for ease of understanding.

[0076] The substrate 26 is generally quadrilateral, with a total of four terminals 27 connected to one end at the front and extending forward. The other ends of each terminal 27, together with two terminals 28 extending from the motor 9, are arranged together and, after the gear cover 7 is injection molded, are disposed in a terminal receiving portion 29 integrally formed on one side, forming a connector 30. A throttle valve opening sensor 21, an intake air temperature sensor 22, and an intake air pressure sensor 23 are disposed on the left side of the substrate 26. Each sensor 21 to 23 is electrically connected to the terminals 27 via a wiring pattern (not shown) formed on the substrate 26.

[0077] Although not shown in the diagram, when the throttle device 1 is installed in the vehicle body, a vehicle-side connector is connected at connector 30. The throttle device 1 is electrically connected to the ECU installed in the vehicle body via the vehicle-side connector and wiring harness. Furthermore, during engine operation, power is supplied from the ECU to the motor 9 and each of the sensors 21-23 via the wiring harness, vehicle-side connector, terminals 27 and 28, and base plate 26 to enable their operation. The detection signals output from each of the sensors 21-23 are input to the ECU along the reverse path described above. Thus, base plate 26 and terminals 27 and 28 act as relays for power and detection signals between the sensors 21-23, the motor 9, and the ECU. However, the structure is not limited to this and can be modified arbitrarily.

[0078] (Throttle valve opening sensor 21)

[0079] like Figure 5 , Figure 6The throttle opening degree sensor 21 is configured by a sensor main body 31 embedded in the gear cover 7 and a magnetic field generating portion 32 provided to the driven gear 18, and is arranged on the throttle axis Cth, as shown. The sensor main body 31 is arranged with six Hall devices 31b between an upper and lower pair of holders 31a, and the terminals 31c of the Hall devices 31b are connected to the substrate 26. The magnetic field generating portion 32 is integrally formed in a ring shape on the right side surface of the driven gear 18 so as to surround the sensor main body 31, and a plurality of magnets 32a are embedded at equal intervals in the circumferential direction.

[0080] Since the principle of the magnetic throttle opening degree sensor 21 is well known, only a general description will be given. When a current flows through the Hall device 31b in the magnetic field generated by the magnet 32a and rotates the magnetic field generating portion 32 together with the throttle shaft 3, a potential difference caused by the Lorentz force is generated at the Hall device 31b according to the rotation angle. The above-mentioned potential difference is converted into an electric signal related to the rotation angle of the throttle shaft 3 and outputted.

[0081] In addition, the throttle opening degree sensor 21 is not limited to the magnetic type, and a member of various principles, such as an inductive sensor, can be used. Since the principle of the above-mentioned sensor is also well known as the magnetic sensor, a detailed description will not be given. For example, a holder including an excitation conductor is fixed to the right side surface of the driven gear 18, and a substrate including an excitation conductor and a signal detection conductor is arranged on the gear cover 7 opposite to the above-mentioned holder. When the driven gear 18 and the throttle shaft 3 rotate together, the excitation conductor on the holder is excited by an alternating current flowing through the excitation conductor of the substrate, and the signal detection conductor of the substrate is excited by the excited current, so as to be converted into an electric signal related to the rotation angle of the throttle shaft 3 and outputted.

[0082] (Intake air temperature sensor 22)

[0083] As Figure 5 , Figure 7As shown, a pair of terminals 33a of the intake air temperature sensor 22 are connected to the substrate 26 and extend to the left, and the sensor main body 33 is supported at the front end thereof. On the inner side surface of the gear cover 7, an elongated rod-shaped seal member 34 extending to the left is integrally formed at the time of injection molding, and the sensor main body 33 and the terminals 33a are embedded in the seal member 34 to constitute the intake air temperature sensor 22. In the state where the gear cover 7 is combined with the throttle device main body 5, the intake air temperature sensor 22 is inserted through the gear housing chamber 6 into a through-hole 35 formed in the throttle device main body 5, and the front end thereof protrudes from a position closer to the front side than the throttle valve 4 in the throttle hole 2. Therefore, the temperature of the intake air flowing in the throttle hole 2 is transmitted to the sensor main body 33 embedded in the front end of the seal member 34. As the intake air temperature sensor 22, for example, a thermistor whose resistance varies with temperature or the like can be used, and the resistance variation is converted into an electric signal related to the intake air temperature and outputted.

[0084] (Intake air pressure sensor 23)

[0085] As shown in Figure 5 , Figure 8 , the sensor main body 36 of the intake air pressure sensor 23 is embedded in the gear cover 7, and the terminals 36a thereof are connected to the substrate 26. On the inner side surface of the gear cover 7, an elongated tube-shaped pressure passage 37 extending to the left is integrally formed at the time of injection molding, and the base end thereof communicates with the intake air pressure sensor 23 via a pressure chamber 38 formed in the gear cover 7, and the front end of the pressure passage 37 is open. In the state where the gear cover 7 is combined with the throttle device main body 5, the pressure passage 37 is inserted through the gear housing chamber 6 into a through-hole 39 formed in the throttle device main body 5, and the front end thereof is opened at a position closer to the rear side than the throttle valve 4 in the throttle hole 2. As a result, the sensor main body 36 of the intake air pressure sensor 23 communicates with the inside of the throttle hole 2 via the pressure chamber 38 and the pressure passage 37, and the pressure of the intake air flowing therein acts on the sensor main body 36.

[0086] As the intake air pressure sensor 23, for example, a semiconductor pressure sensor, a strain gauge pressure sensor, or the like can be used. The principle of the above pressure sensor is well known, and thus a detailed description will not be given, but the semiconductor pressure sensor causes pressure to act on a diaphragm forming surface of a silicon gauge, and converts a resistance variation (piezoresistive effect) resulting from the deflection of the silicon gauge corresponding to the pressure into an electric signal related to the intake air pressure and outputs the same. Further, the strain gauge pressure sensor causes pressure to act on a metal diaphragm having a resistance bridge adhered to the back surface thereof, and converts a voltage variation of the resistance bridge corresponding to the deflection of the metal diaphragm into an electric signal related to the intake air pressure and outputs the same.

[0087] As shown in Figure 5As shown, the intake air temperature sensor 22 is disposed in front of the throttle valve opening degree sensor 21, and the intake air pressure sensor 23 is disposed above and behind the throttle valve opening degree sensor 21. Therefore, the two sensors 22, 23 can be embedded in the gear cover 7 without increasing the thickness of the gear cover 7. As a result, the throttle device 1 includes the throttle valve opening degree sensor 21, the intake air temperature sensor 22, and the intake air pressure sensor 23, which are all disposed in the gear cover 7.

[0088] The above is a portion common to the first embodiment and the second embodiment, and the characteristic portion of the first embodiment will be described next.

[0089] (First Embodiment)

[0090] As shown in Figs. 1 and 2, the throttle device 1 according to the first embodiment includes a throttle valve 4, a throttle valve opening degree sensor 21, an intake air temperature sensor 22, an intake air pressure sensor 23, and a gear cover 7. Figure 2 、 Figure 5 、 Figure 9 As shown, the driven gear 18 is circular with the throttle valve axis Cth as the center, and teeth are formed on the outer periphery thereof only in a region slightly wider than 90° in which the small-diameter portion 17b of the intermediate gear 17 is engaged. Therefore, the intake air temperature sensor 22 and the intake air pressure sensor 23, which are disposed on the gear cover 7 as described above, overlap the driven gear 18 when viewed from the right, and the pressure passages 37 of the intake air temperature sensor 22 and the intake air pressure sensor 23 interfere with the driven gear 18 when passing through the gear housing chamber 6. Therefore, to prevent interference, the first through groove 41 for the intake air temperature sensor 22 and the second through groove 42 for the pressure passages 37 are formed in the driven gear 18.

[0091] Briefly, each of the through grooves 41, 42 is formed along a path in which the intake air temperature sensor 22 and the pressure passages 37 relatively move in conjunction with the rotation of the driven gear 18. In detail, the driven gear 18 is circular with the throttle valve axis Cth as the center, and the first through groove 41 and the second through groove 42 are formed along a circular arc-shaped path in which the intake air temperature sensor 22 and the pressure passages 37 relatively move in conjunction with the rotation of the driven gear 18. Figure 5 As shown, the driven gear 18 rotates clockwise to reach one end of the stroke when the throttle valve 4 is fully closed, and rotates counterclockwise to reach the other end of the stroke when the throttle valve 4 is fully open. Figure 9 As shown, the driven gear 18 rotates clockwise to reach one end of the stroke when the throttle valve 4 is fully closed, and rotates counterclockwise to reach the other end of the stroke when the throttle valve 4 is fully open.

[0092] As a result, each through-slot 41 and 42 is an arc with a length of approximately 90° centered on the throttle valve axis Cth. A small gap is always maintained between its inner circumference and the intake air temperature sensor 22 and pressure passage 37, regardless of the rotation angle of the driven gear 18. Therefore, when the throttle valve 4 is opened and closed by the motor 9, the driven gear 18 rotates without interfering with the intake air temperature sensor 22 and pressure passage 37, thus fulfilling its rotational transmission function without any problems.

[0093] like Figure 5 As shown, the driven gear 18 is circular, with a magnetic field generating section 32 for the throttle valve opening sensor 21 formed at its center. Therefore, the area on the driven gear 18 where the first through groove 41 and the second through groove 42 can be formed is limited to the annular area surrounding the magnetic field generating section 32. By making each through groove 41, 42 arc-shaped, the limited area on the driven gear 18 can be effectively utilized, and interference with the intake air temperature sensor 22 and the pressure passage 37 can be reliably prevented.

[0094] In this embodiment, since the intake air temperature sensor 22 and the pressure passage 37 are arranged with the same diameter and at equal distances from the throttle valve axis Cth, the width and radius of curvature of the first through groove 41 and the second through groove 42 are set to be the same, but this is not a limitation. When the outer diameters of the intake air temperature sensor 22 and the pressure passage 37 and their distances from the throttle valve axis Cth are different, the shapes of the first through groove 41 and the second through groove 42 can also be set separately with corresponding widths and radii of curvature. Furthermore, as described above, the arc-shaped first through groove 41 and the second through groove 42 are reasonable shapes, but this is not a limitation, and shapes other than arc-shaped can also be used.

[0095] The interference prevention achieved by the through slots 41 and 42 as described above means that the slots can be arbitrarily determined without being limited by the presence of the driven gear 18. Figure 5 The positions of the intake air temperature sensor 22 and the pressure passage 37 are shown when viewed from the right. Since the position of the intake air pressure sensor 23 is also determined corresponding to the position of the pressure passage 37, in other words, the positions of the intake air temperature sensor 22 and the intake air pressure sensor 23 on the gear cover 7 can be determined without being limited by the presence of the driven gear 18. Therefore, based on... Figure 5 As described, the intake air temperature sensor 22 and intake air pressure sensor 23 can be positioned appropriately on the gear cover 7 by utilizing the dead zone around the throttle valve opening sensor 21. Thus, three sensors, including the throttle valve opening sensor 21, are concentrated on the gear cover 7 with almost no increase in thickness.

[0096] In the throttling device of Patent Document 1, a gear housing chamber is provided on one side of the throttling device body, and a sensor unit consisting of an intake air temperature sensor and an intake air pressure sensor is provided on the other side. However, in this embodiment, the function of the aforementioned sensor unit is achieved by the gear cover 7. As a result, in this embodiment, the space occupied by the throttling device 1 in the left-right direction can be reduced by an amount equivalent to the left-right thickness of the sensor unit, thereby achieving compactness.

[0097] In particular, the throttling device 1 of this embodiment is installed on a bicycle with a small frame and a prime mover, and is surrounded not only by auxiliary equipment for the engine, but also by a fuel tank, frame, etc. Therefore, if the throttling device 1 is not sufficiently compact, there may be situations where countermeasures on the frame side are needed to prevent interference, but such adverse situations can be prevented. In addition, since no component equivalent to the gear unit in Patent Document 1 is required, the number of parts can be reduced and the overall structure of the throttling device 1 can be simplified, which is a major reason for reducing manufacturing costs.

[0098] Furthermore, changes in the positions of the intake air temperature sensor 22 and the pressure passage 37 also affect the configuration of the throttle orifice 2. However, since it is not necessary to change its position, the throttle orifice 2 can be kept in its original suitable position on the throttle device 1. In addition, the interference prevention achieved by the aforementioned through slots 41 and 42 also has the following effect: based on the proper placement of the intake air temperature sensor 22 and the intake air pressure sensor 23, the driven gear 18 can be configured without being restricted by the positions of the aforementioned components 22 and 23. As a result, the structure of the gear train 8 can be further freely designed, such as the number and arrangement of gears. Based on the above main reasons, the overall design freedom of the throttle device 1 can also be improved.

[0099] On the other hand, such as Figure 5 As shown, in this embodiment, in order to achieve the desired reduction ratio by the gear train 8, an intermediate gear 17 is provided between the drive gear 16 and the driven gear 18. Therefore, when viewed from the right, the large diameter portion 17a of the intermediate gear 17 partially overlaps with the driven gear 18. Furthermore, an intake air temperature sensor 22 and a pressure passage 37 are arranged at a position avoiding the aforementioned overlapping area. With the configuration described above, the intake air temperature sensor 22 and the pressure passage 37 pass through the gear housing 6 without being obstructed by the intermediate gear 17, and interference with the driven gear 18 can be prevented by forming through slots 41 and 42.

[0100] Furthermore, as is well known, the intake air temperature requires the intake air immediately after entering the throttle orifice 2, in other words, the intake air upstream of the throttle valve 4, to be measured. Therefore, the front end of the intake air temperature sensor 22 needs to protrude upstream of the throttle valve 4 within the throttle orifice 2. Additionally, the intake air pressure requires the intake air that generates negative pressure via the throttle valve 4, in other words, the intake air downstream of the throttle valve 4, to be measured. Therefore, the pressure passage 37 needs to open downstream of the throttle valve 4 within the throttle orifice 2.

[0101] In this embodiment, according to the aforementioned positional requirements, the intake air temperature sensor 22 is positioned upstream of the throttle valve 4, and the intake air pressure sensor 23 and pressure passage 37 are positioned downstream of the throttle valve 4. With this configuration, the intake air temperature sensor 22 and pressure passage 37 are arranged in a simple straight line extending to the left from the gear cover 7, and the through holes 35 and 39 of the throttle device body 5 through which the aforementioned components 22 and 37 are inserted also function without problems in a straight line shape. As a result, other effects such as simplifying the structure of the gear cover 7 and the throttle device body 5 can also be achieved.

[0102] Furthermore, in this embodiment, a pressure passage 37 is integrally formed at the gear cover 7. To connect the intake pressure sensor 23 on the gear cover 7 side and the throttling orifice 2 on the throttling device body 5 side via the pressure passage 37, the pressure passage 37 can be integrally extended to the right from the throttling device body 5 and connected to the intake pressure sensor 23, but the connection needs to be airtightly maintained using an O-ring or similar device. Because it is integrally formed with the gear cover 7, it functions as a passage simply by opening the front end of the pressure passage 37 within the throttling orifice 2; therefore, this also contributes to simplifying the structure of the throttling device 1.

[0103] (Second Implementation)

[0104] The difference from the first embodiment is that a notch 51 is formed at the driven gear 18 to replace the first through groove 41 and the second through groove 42. Therefore, the difference will be described in detail.

[0105] like Figures 10-12 As shown, in the driven gear 18 of this embodiment, a notch 51 is formed by cutting away the area without teeth within the outer periphery of a circle centered on the throttle valve axis Cth. The notch 51 is shaped to include the path through which the intake air temperature sensor 22 and the pressure passage 37 move relative to each other as the driven gear 18 rotates, and more specifically, it is a fan shape of more than 180° centered on the throttle valve axis Cth. The intake air temperature sensor 22 and the pressure passage 37 are disposed within the notch 51.

[0106] Thus, a slight gap is always formed between the notch 51 and the intake temperature sensor 22 and the pressure passage 37, regardless of the rotational angle of the driven gear 18. Therefore, when the throttle valve 4 is opened and closed by the drive motor 9, the driven gear 18 rotates without interfering with the intake temperature sensor 22 and the pressure passage 37, and functions as a rotation transmission without any problem.

[0107] In addition, the shape of the notch 51 is not limited to the sector shape as described above, and can be arbitrarily changed as long as interference is prevented.

[0108] Although not described repeatedly, all the effects described in the first embodiment can be achieved according to the present embodiment. For example, by providing the notch 51 as a sector shape, as with the circular-arc-shaped through grooves 41, 42 of the first embodiment, the limited area on the driven gear 18 can be effectively utilized to prevent interference.

[0109] The description of the embodiments has been completed, but the modes of the present application are not limited to the above-described embodiments. For example, although the throttle device 1 including a single throttle hole 2 mounted on a bicycle with a prime mover is embodied in the above-described embodiments, the use and the form of the throttle device 1 are not limited thereto. The present application can be applied to all kinds of riding vehicles in which a rider rides in a manner of straddling a saddle, and as such riding vehicles, there are not only two-wheeled vehicles (bicycles with a prime mover and the like) provided with a small displacement engine, such as a scooter and a moped, but also two-wheeled vehicles (automatic two-wheeled vehicles and the like) provided with a larger displacement engine or an ATV (All Terrain Vehicle) and the like. Therefore, the engine mounted on the above-described various vehicles as a traveling power source can be taken as an object, and the throttle device of the present application can be arbitrarily applied. In addition, the throttle device of the present application can be applied to an engine used for a use other than a traveling power source, such as an engine for a generator and the like. In addition, a multi-throttle device including a plurality of throttle holes can be embodied.

[0110] In addition, in the above-described embodiments, three kinds of sensors, the throttle opening degree sensor 21, the intake temperature sensor 22, and the intake pressure sensor 23 are included, but for example, the throttle opening degree sensor 21 can be omitted according to a request from engine control or the like. In addition, it is not necessary to respectively arrange the intake temperature sensor 22 and the pressure passage 37 through the gear housing chamber 6, and it is not necessary to form the avoidance portions 41, 42, 51 corresponding to them at the driven gear 18. For example, either one of the intake temperature sensor 22 and the pressure passage 37 can be arranged so as not to pass through the gear housing chamber 6, and can reach the throttle hole 2 from the gear cover 7 to the throttle device main body 5 along a path that bypasses the gear housing chamber 6. In this case, the avoidance portions 41, 42, 51 for preventing interference with either one are not needed.

[0111] Further, in the above-described embodiment, the gear train 8 is provided with the drive gear 16, the intermediate gear 17, and the driven gear 18, but the structure of the gear train 8 is not limited thereto, and the number of gears, the arrangement, and the like can be changed.

Claims

1. A throttling device for an engine, characterized in that, include: The throttle body has a throttle orifice that communicates with the cylinder when installed in the engine. A throttle valve is supported in the throttle orifice by a throttle valve shaft so that it can be opened and closed, and the throttle valve shaft protrudes from the outer side toward one side. A gear cover that closes the outer side of the throttling device body from one side and divides out a gear receiving chamber; A gear train, housed within the gear housing chamber, and consisting of at least a driven gear fixed to the throttle valve shaft and a drive gear that transmits rotation to the driven gear, and disposed between the gear cover and the throttle device body in the direction along the throttle valve shaft; A motor is mounted on the main body of the throttling device, and the drive gear is fixed at the output shaft protruding into the gear receiving chamber. The motor opens and closes the throttling valve via the gear train to regulate the amount of intake air flowing in the throttling orifice. An intake air temperature sensor is disposed on the gear cover and its front end protrudes into the throttling orifice of the throttling device body to detect the temperature of the intake air flowing in the throttling orifice. as well as An intake pressure sensor is disposed on the gear cover and communicates with the throttling orifice of the throttling device body via a pressure passage to detect the pressure of the intake air flowing within the throttling orifice. At least one of the intake air temperature sensor and the pressure passage is configured to overlap with the driven gear when viewed from the direction along the throttle valve axis, and extends through the gear housing chamber toward the throttle orifice. At the driven gear, an arc-shaped through groove is formed along the path of relative movement of at least one of the intake air temperature sensor and the pressure passage as the driven gear rotates. At least one of the intake air temperature sensor and the pressure passage is inserted into the through slot to prevent interference with the driven gear.

2. The throttling device for the engine as described in claim 1, characterized in that, An intermediate gear is provided between the driving gear and the driven gear. This intermediate gear consists of a large-diameter portion that meshes with the driving gear and a small-diameter portion that meshes with the driven gear. Viewed from the direction along the throttle valve axis, at least one of the intake air temperature sensor and the pressure passage is positioned to avoid the area where the large diameter portion of the intermediate gear overlaps with the driven gear.

3. The throttling device for the engine as described in claim 1, characterized in that, The pressure passage is integrally formed on the gear cover and is tubular, passing through the gear receiving chamber and opening at the front end in the throttling hole through a through hole formed in the body of the throttling device.

4. The throttling device for the engine as described in claim 1, characterized in that, The intake air temperature sensor and the pressure passage are respectively positioned at locations overlapping the driven gear when viewed from along the throttle valve axis, and both extend through the gear housing chamber. The driven gear has through slots formed to prevent interference with the intake air temperature sensor and the pressure passage, respectively.

5. The throttling device for the engine as described in claim 4, characterized in that, The intake air temperature sensor is positioned upstream of the throttle valve in the intake air flow direction, relative to the throttle valve within the throttle orifice. The intake pressure sensor and the pressure passage are positioned downstream of the throttle valve in the intake flow direction, relative to the throttle valve within the throttle orifice.

6. The throttling device for the engine as described in claim 1, characterized in that, The gear cover is equipped with a throttle valve opening sensor at a position on the axis of the throttle valve shaft to detect the throttle valve opening. The intake air temperature sensor and the intake air pressure sensor are disposed in the area surrounding the throttle valve opening sensor on the gear cover.

7. The throttling device for the engine as described in claim 1, characterized in that, The throttling device has a single throttling orifice and is installed on a single-cylinder engine, which is used as a power source for riding in a vehicle.

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