Throttle device

Abstract

To effectively suppress intrusion of moisture from a portion around a shaft of a motor that moves a valve element for opening / closing a bypass passage of a throttle to a housing of the motor.SOLUTION: A throttle device (1) includes: a body member (2, 50, 60) in which a main passage (7) having a throttle valve (14) and a bypass passage (70) bypassing the throttle valve are formed; a valve element (110) for opening / closing the bypass passage; an actuator (108) that moves the valve element via a shaft (127); a housing (112) disposed in an accommodation part (58) formed in the body member and accommodating the actuator; an insertion hole (125) that is formed in the housing and through which the shaft is inserted; and pressure fluctuation suppression means (200, 68, 210) for suppressing pressure fluctuation of the accommodation part.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present technology relates to a throttle device. [Background technology]

[0002] Vehicles equipped with engines, such as boats, motorcycles, and mopeds, are usually equipped with a throttle device that controls the amount of air intake to the engine. In addition to a main passage (bore) in which a throttle valve is disposed, the throttle device may be provided with a bypass passage that bypasses the throttle valve for idling. The bypass passage is usually provided with a valve for controlling the idling speed.

[0003] [Patent Document 1] Patent Publication No. 2022-167201 [Patent Document 2] JP 2020-060269 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0004] When a valve body that opens and closes a bypass passage is operated by a motor, the area around the shaft protruding from the motor housing may not be completely sealed, in which case humid air may enter and cause rust on motor parts such as the windings. In particular, when the engine is stopped, the engine and motor stop generating heat, which creates negative pressure inside the housing and makes it easy for air to be drawn in, and moisture is likely to condense inside the housing. Furthermore, in the case of a throttle device installed on a ship, there is a very high possibility that air with high humidity and salinity may enter, which can make the rust problem more serious.

[0005] Various methods have been proposed for sealing the shaft protruding from the motor housing. For example, JP 2022-167201 A discloses that the shaft protruding from the coil case is always covered with a bellows-shaped cover to prevent moisture from entering the coil case. However, if a pressure change occurs inside the housing, the bellows is likely to deform significantly and crack, so a sufficient sealing function cannot be expected. Even if the sealing function can be maintained, a powerful motor is required to obtain a large driving force that can overcome the pressure change, which increases costs.

[0006] Japanese Patent Application Publication No. 2020-060269 discloses that a seal member is placed around the shaft that protrudes from the coil case into the flow path, and the valve body is seated on the seal member when the solenoid valve is opened. However, if this structure is applied to a step motor, there is a high possibility that the valve body will lose synchronization before reaching the fully open position, so sufficient sealing function cannot be expected.

[0007] It is therefore desirable to solve at least one of the above problems and effectively prevent moisture from entering the housing from around the shaft of the motor of the throttle device. [Means for solving the problem]

[0008] One aspect is a throttle device comprising a body member in which a main passage having a throttle valve and a bypass passage that bypasses the throttle valve are formed, a valve body that opens and closes the bypass passage, an actuator that moves the valve body via a shaft, a housing that is disposed within an accommodating portion formed in the body member and accommodates the actuator, an insertion hole formed in the housing through which the shaft is inserted, and pressure fluctuation suppression means that suppresses pressure fluctuations in the accommodating portion.

[0009] In some embodiments, the pressure fluctuation suppressing means includes a diaphragm disposed facing the bypass passage.

[0010] In some embodiments, the body member includes a first body member forming the main passage and a second body member forming the accommodating portion, the bypass passage is formed between the first body member and the second body member, the diaphragm is disposed in a reduced-weight portion of the second body member facing the bypass passage, and the pressure fluctuation suppression means includes a communication hole communicating between the reduced-weight portion and the accommodating portion.

[0011] In some embodiments, a sealing member is provided around the insertion hole to contact the valve body or the housing and seal the insertion hole when the valve body moves in the opening direction, the actuator is provided with a step motor, and a stopper member is provided between the valve body and the housing to determine the fully open position of the valve body by abutting against the valve body or the housing, and when the valve body moves in the opening direction, the sealing member contacts the valve body or the housing to seal the insertion hole before the stopper member abuts against the valve body or the housing.

[0012] Another aspect is a throttle device comprising: a body member in which a main passage having a throttle valve and a bypass passage that bypasses the throttle valve are formed, a valve body that opens and closes the bypass passage, a step motor that moves the valve body via a shaft, a housing that is disposed in an accommodating portion formed in the body member and accommodates the step motor, and an insertion hole formed in the housing through which the shaft is inserted. The throttle device further comprises a seal member disposed around the insertion hole to contact the valve body or the housing and seal the insertion hole when the valve body moves in an opening direction, and a stopper member disposed between the valve body and the housing to determine a fully open position of the valve body by contacting the valve body or the housing, and when the valve body moves in the opening direction, the seal member contacts the valve body or the housing to seal the insertion hole before the stopper member contacts the valve body or the housing. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view of a throttle device according to one embodiment, taken along a plane passing through a center line of a main passage (bore) and a center line of a throttle shaft. [Diagram 2] 2 is a cross-sectional view of the throttle device taken along a plane passing through the centerline of the main passage (bore) and perpendicular to the centerline of the throttle shaft, as viewed from below in FIG. 1. [Diagram 3] FIG. 2 is a perspective view of the throttle device with the IDU body disassembled from the throttle body. [Figure 4] FIG. 2 is a plan view of the throttle body as viewed from above in FIG. [Diagram 5] FIG. 2 is a perspective view of the underside of the IDU body. [Figure 6] 2 is a cross-sectional view of the throttle device taken along a plane passing through the center line of the ISC valve and along a bypass passage. FIG. [Figure 7] FIG. 2 is a perspective view of a step motor and a valve body of the ISC valve. [Figure 8] FIG. 13 is a schematic diagram showing an external pressure change suppression device according to another embodiment. [Figure 9] FIG. 2 is a diagram illustrating the ISC valve when the valve disc is in a closed position. [Figure 10] FIG. 2 is a diagram illustrating the ISC valve when the valve disc moves in the opening direction and comes into contact with the lip seal. [Figure 11] 1 is a diagram illustrating the ISC valve when the valve body comes into contact with the stopper member and reaches the fully open position. FIG. [Figure 12] FIG. 13 shows a lip seal attached to a valve body as another embodiment. [Figure 13] FIG. 13 illustrates an O-ring attached to a motor housing as yet another embodiment. [Figure 14] FIG. 13 shows an O-ring attached to a valve body as yet another embodiment. [Figure 15] FIG. 13 illustrates a resilient bellows attached to a motor housing as yet another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Various embodiments of the present technology will be described below with reference to the drawings.

[0015] Vehicles and transport machines equipped with engines, such as boats (outboard motors and inboard motors), motorcycles, and mopeds, are usually equipped with a throttle device 1 as shown in Fig. 1, which is provided in an intake pipe communicating with the engine and controls the amount of intake air to the engine. The up-down direction in Fig. 1 and Fig. 3 is drawn so as to coincide with the up-down direction of the throttle device 1 mounted on a boat as one embodiment.

[0016] [Throttle body and throttle valve] As shown in Fig. 1, the throttle device 1 has a throttle body 2 made of metal (for example, an aluminum alloy), and the throttle body 2 has a bore forming portion 6 that forms a generally cylindrical main passage 7 (bore) that passes through. The upstream side of the main passage 7 is connected to the atmosphere and can be provided with an air cleaner. The downstream side of the main passage 7 is connected to the engine via an intake piping such as an intake manifold. Air drawn in from the atmosphere passes through the main passage 7 of the throttle device 1 and is taken into the engine.

[0017] As shown in Figures 1 and 2, a butterfly-type disc-shaped throttle valve 14 is disposed inside the main passage 7, and is supported by the throttle shaft 9 to open and close the main passage 7. The throttle valve 14 is fixed to the throttle shaft 9 by a screw 15 or the like. The throttle shaft 9 is rotatably held by the throttle body 2, and crosses the main passage 7 in the diametrical direction. The throttle valve 14 rotates between a closed position (position shown in Figure 2) and an open position (not shown) by the rotation of the throttle shaft 9, and controls the amount of intake air passing through the main passage 7. The throttle shaft 9 is inserted into shaft insertion holes 10, 11 formed in the throttle body 2 on both sides of the throttle valve 14, and is rotatably held by bearings 19, 20. Each shaft insertion hole 10, 11 is sealed by an elastic seal member 12, 13, such as a lip seal, disposed between the throttle shaft 9 and the wall surface of each shaft insertion hole 10, 11.

[0018] [Throttle lever] As shown in Figure 1, one end of the throttle shaft 9 protrudes from the throttle body 2, and a throttle lever 17 is coupled to this protruding portion. The throttle lever 17 is connected, for example, to a throttle handle operated by the driver via a transmission member such as a cable. A return spring 18 made of a torsion coil spring is interposed between the throttle lever 17 and the throttle body 2. The return spring 18 biases the throttle valve 14 in the closing direction via the throttle lever 17. The rotation of the throttle lever 17 in the closing direction is restricted by a stopper 21 (see Figure 3) fixed to the outside of the throttle body 2.

[0019] [Intake device unit] As shown in Figure 1, the throttle device 1 includes an intake device unit (IDU) 3 that is attached to a throttle body 2. The IDU 3 is a single module formed by assembling devices such as valves and various sensors required for intake control (hereinafter referred to as "intake devices") into a plastic IDU body 50. The IDU body 50 has a connector insertion section 97 into which an external connector is inserted to electrically connect the intake device to an external electronic control unit (ECU). The ECU receives output signals from various detection devices such as sensors and switches, and sends control signals to actuators such as motors.

[0020] As shown in Fig. 3, the throttle body 2 has a flange-shaped IDU coupling portion 26 having a mating surface 26a for coupling the IDU 3. The mating surface 26a is formed, for example, in a direction perpendicular to the throttle shaft 9 (i.e., the rotation axis of the throttle valve 14). The IDU body 50 has a mating surface 50a that is coupled to the mating surface 26a of the IDU coupling portion 26 of the throttle body 2. To enable attachment and detachment of the IDU 3, for example, a plurality of boss portions 44 are formed on the outer periphery of the IDU coupling portion 26 of the throttle body 2, and corresponding boss portions 62 are also formed on the outer periphery of the IDU body 50. The IDU body 50 is coupled to the throttle body 2 by threading a fastening bolt (not shown) passed through an insertion hole 62a of each boss portion 62 of the IDU body 50 into a screw hole 44a of the corresponding boss portion 44 of the throttle body 2.

[0021] The intake device is assembled into a recessed accommodation portion 58 from the opposite side of the mating surface 50a, from the opposite side to the throttle body 2. An IDU cover 60 (see Figures 1 and 6) is joined to the IDU body 50 by an appropriate method such as welding, bonding, bolting, snap fitting, etc., to close the accommodation portion 58 of the IDU body 50 in which the intake device is disposed. The internal space of the IDU 3 is sealed against the outside by selecting an appropriate joining method, or by placing an elastic sealing member between the IDU body 50 and the IDU cover 60 as necessary.

[0022] [Bypass passage] As shown in Fig. 6, by joining the IDU body 50 to the throttle body 2, a bypass passage 70 that bypasses the throttle valve 14 is formed. The bypass passage 70 branches off from the main passage 7 upstream of the throttle valve 14 and merges with the main passage 7 downstream of the throttle valve 14. Specifically, a passage groove 37 (see also Fig. 3) deeply recessed from the mating surface 26a is formed in the IDU joining portion 26 of the throttle body 2. An inlet hole 28 and an outlet hole 30 each penetrate the bore forming portion 6 from the passage groove 37 and open into the wall surface of the main passage 7. This allows a portion of the intake air flowing through the main passage 7 to flow from the inlet hole 28 through the bypass passage 70 and out of the outlet hole 30 into the main passage 7 (see also Figs. 1 and 2).

[0023] [ISC valve] As shown in FIG. 6, the throttle device 1 is provided with an idle speed control (ISC) valve 51 that adjusts the amount of intake air passing through the bypass passage 70. The ISC valve 51 is mainly controlled by the ECU when the engine is idling. The ISC valve 51 is attached to the housing portion 58 of the IDU body 50. The ISC valve 51 includes a valve body 110 that moves linearly between a fully closed position (dashed line in FIG. 6) and a fully open position (solid line) to open and close the bypass passage 70, and an actuator that moves the valve body 110 via a shaft 127. The actuator can be, for example, a step motor 108, but in another embodiment, a motor other than a step motor, such as a DC motor or a brushless motor, can also be used. The throttle body 2 has a valve seat 33 on which the valve body 110 sits at the bottom of the passage groove 37 (the inlet portion of the outlet hole 30). The valve body 110 has a tapered seal surface 133 that faces the valve seat 33.

[0024] The step motor 108 has a motor housing 112, and although not shown, is equipped with a stator having windings and a rotor having magnets inside the motor housing 112. The stator has a resin bobbin for holding the windings. The bobbin is integrally equipped with a terminal support portion 120 that protrudes from an opening provided in the side of the motor housing 112, and the terminal support portion 120 holds a terminal 117 by insert molding (see FIG. 7). The terminal 117 of the step motor 108 is in electrical contact with a terminal plate connected to a terminal of the connector insertion portion 97. A shaft 127 is rotatably supported by the motor housing 112 via a bearing (not shown), and the rotor is coupled to this shaft 127.

[0025] The step motor 108 is fitted into a motor fitting portion 72 (see also FIG. 3) formed in the IDU body 50. An O-ring 63 (see also FIG. 7) is disposed between the motor housing 112 and the wall surface of the motor fitting portion 72. This seals the internal space of the IDU 3 from the bypass passage 70.

[0026] [Screw engagement between screw shaft and nut] As shown in FIG. 6, the shaft 127 protrudes outward from the insertion hole 125 of the motor housing 112, and a threaded shaft portion 129 is formed on the protruding portion. A nut 136 having a threaded hole is press-fitted into the recessed hole 254 of the valve body 110. The threaded shaft portion 129 of the shaft 127 is screwed into the nut 136. The valve body 110 is prevented from rotating while being slidable relative to the IDU body 50 by a combination of a groove 134a (see FIG. 7) extending in the axial direction of the ISC valve 51 and a linear protrusion 76. Specifically, the linear protrusion 76 is formed on the inner peripheral surface of the motor fitting portion 72, and a groove 134a is formed on the outer peripheral surface of the flange portion 134 of the valve body 110 corresponding to the linear protrusion 76. As a result, when the step motor 108 rotates, the valve body 110 moves in the axial direction via the screwing action of the shaft 127 and the nut 136. When the valve body 110 advances, the outlet hole 30 is closed, and when the valve body 110 retreats, the outlet hole 30 is opened.

[0027] In another embodiment (not shown), the actuator of the ISC valve 51 may be an actuator in which the shaft 127 itself moves back and forth to move the valve body 110. For example, an actuator other than a motor, such as a motor having a screw shaft and a nut inside a housing, or an electromagnetic solenoid, may be used.

[0028] [Spring] As shown in FIG. 6, the motor fitting portion 72 has a cylindrical protrusion 74 protruding from the mating surface 50a into the passage groove 37 of the throttle body 2. A circular enlarged portion 32 (see FIG. 3) is formed at the end of the passage groove 37 of the throttle body 2 to receive the protrusion 74 of the motor fitting portion 72. An inwardly extending flange portion 75 is formed at the end of the cylindrical protrusion 74. The valve body 110 protrudes into the passage groove 37 through an opening formed by this inwardly facing flange portion 75. A spring 138 made of a coil spring is interposed between the flange portion 134 of the valve body 110 and the inwardly facing flange portion 75 at the bottom of the motor fitting portion 72. One end of the spring 138 fits into an annular recess 134b formed in an annular shape in the flange portion 134 of the valve body 110.

[0029] [Throttle position sensor] As shown in Fig. 1, the throttle device 1 can also be provided with a throttle position sensor for detecting the orientation (angle) of the throttle valve 14. The throttle position sensor is attached to the housing portion 58 of the IDU body 50. The throttle position sensor is configured to include, for example, a sensor rotor 143 fixed to the end of the throttle shaft 9, and to electrically detect the position of the brush of the sensor rotor 143 using a resistor plate arranged on the surface of the wiring board 55. A through-hole 64 for receiving the end of the throttle shaft 9 is formed in the IDU body 50. In this way, the internal space of the IDU communicates with this throttle body 2, but is sealed from the main passage 7 by the seal member 12 arranged around the throttle shaft 9 as described above.

[0030] [Pressure sensor] The throttle device 1 may also be provided with a pressure sensor (not shown) for measuring the pressure of the intake air flowing through the main passage 7. The pressure sensor is disposed in the housing portion 58 of the IDU body 50, and is attached to the wiring board 55, for example. As shown in FIG. 5, a through-hole 78 is formed in the bottom surface of the housing portion 58 of the IDU body 50, penetrating to the mating surface 50a, and the main body of the pressure sensor is disposed in this through-hole 78. A seal member (not shown) is disposed between the main body of the pressure sensor and the through-hole 78. As shown in FIG. 1, the throttle body 2 is formed with a communication hole 38 that penetrates from the mating surface 26a through the bore forming portion 6 and opens into the wall surface of the main passage 7 (on the downstream side of the throttle valve 14). The communication hole 38 is communicated with the through-hole 78 through a communication passage 40 (see also FIGS. 3 and 5) that is formed to weave between the IDU body 50 and the throttle body 2. In this way, the detection portion of the pressure sensor is disposed in a space connected to the main passage 7 of the throttle body 2, but because a sealing member is disposed around the main body of the pressure sensor, the internal space of the IDU 3 does not communicate with the main passage 7.

[0031] [Temperature sensor] The throttle device 1 can also be provided with a temperature sensor (not shown) that detects the temperature of the intake air flowing through the main passage 7. The temperature sensor is attached to the housing 58 of the IDU body 50. As shown in FIG. 5, the IDU body 50 is formed with a cylindrical portion 81 with a closed tip that protrudes from the mating surface 50a, and a detection portion of the temperature sensor is inserted into this cylindrical portion 81. As shown in FIGS. 2 and 3, the throttle body 2 is formed with a through hole 42 for inserting the temperature sensor, which penetrates the bore forming portion 6 from the mating surface 26a and opens into the wall surface of the main passage 7 (on the upstream side of the throttle valve 14), and the cylindrical portion 81 of the IDU body 50 is fitted into this through hole 42. In this way, the detection portion of the temperature sensor is located inside the wall surface of the main passage 7, but since the tip of the cylindrical portion 81 is closed, the internal space of the IDU 3 does not communicate with the main passage 7.

[0032] [gasket] As shown in Fig. 6, the mating surface 26a of the throttle body 2 and the mating surface 50a of the IDU body 50 can be sealed with one or more elastic sealing members, such as a gasket 180, formed in a shape that surrounds holes and recesses opening therein. The gasket 180 can be attached, for example, to a fitting groove 90 (see Fig. 5) formed in the IDU body 50. When the IDU body 50 is joined to the throttle body 2 by such a gasket 180, the holes and recesses opening in the mating surface 50a of the IDU body 50 and the mating surface 26a of the throttle body 2 are sealed against the outside of the throttle device 1 or against other holes and recesses.

[0033] [Pressure change suppression means] If the accommodation section 58 of the IDU body 50 is sealed with various sealing members, the pressure inside the motor housing 112 and inside the accommodation section 58 communicating therewith tends to fluctuate due to temperature differences caused by heat generation and radiation, particularly from the step motor 108 of the ISC valve 51. In particular, if negative pressure occurs inside the motor housing 112 and humid air is drawn in, there is a possibility that the components of the step motor 108 will rust. Therefore, the throttle device 1 can be provided with a means for suppressing such pressure changes. To suppress pressure changes, for example, a configuration can be adopted that allows volumetric changes inside the IDU 3 or in the space communicating therewith.

[0034] [Diaphragm and communication hole] As shown in FIG. 6, in one embodiment, the diaphragm 200 can be disposed so as to face the bypass passage 70. The diaphragm 200 is an elastic membrane and can be formed of an elastic material (elastomer). The diaphragm 200 can be disposed, for example, in a recessed portion 68 (see also FIG. 5) formed so as to be recessed from the mating surface 50a of the IDU body 50. The recessed portion 68 is usually provided for the purpose of reducing material costs, and is formed, for example, in an area of ​​the IDU body 50 corresponding to a part of the passage groove 37 of the throttle body 2 (a part excluding the circular expansion portion 32). The diaphragm 200 can be attached, for example, by fixing the outer peripheral frame 202 to the wall surface of the recessed portion 68. The IDU body 50 is formed with a communication hole 210 (or a large communication space) that penetrates from the housing portion 58 to the recessed portion 68. As a result, a small space 220 formed by the recessed portion 68 and the diaphragm 200 communicates with the housing portion 58.

[0035] In another embodiment not shown, the diaphragm can be disposed so as to face the main passage 7. In this case, the diaphragm can also be attached by fixing its peripheral portion to the surrounding structure by an appropriate method such as gluing or welding. Also, communication holes penetrating the IDU body 50 and the throttle body 2 are appropriately provided. In short, it is sufficient that the space communicating with the main passage 7 and the bypass passage 70 and the space communicating with the accommodation portion 58 are partially partitioned by the diaphragm.

[0036] In another embodiment (not shown), a diaphragm may be disposed to partition the storage section 58 closed by the IDU cover 60, and the space in which the motor housing 112 is not disposed may be connected to the outside (atmosphere) through a communication hole. In yet another embodiment (not shown), a part of the IDU body 50 or IDU cover 60 that forms the storage section 58 may be formed of a diaphragm. In this last embodiment, the communication hole is not necessary.

[0037] [External pressure change suppression device] As shown in Fig. 8, in another embodiment, a volume-variable container 230 that communicates with the storage section 58 of the IDU body 50 can be provided outside the IDU body 50. An example of such a container is a container having an expandable structure such as a bellows 232. Such a volume-variable container can be connected to a hole penetrating the IDU body 50 by a connecting pipe 234, or can be a container that directly covers the hole penetrating the IDU body 50.

[0038] [Stopper and elastic seal] As shown in Figs. 9 to 11, an elastic seal member is disposed around the insertion hole 125 through which the shaft 127 of the motor housing 112 is inserted, contacting the valve body 110 to seal the insertion hole 125 when the valve body 110 moves in the opening direction (upward in the figures). The elastic seal member is, for example, annular or cylindrical. The elastic seal member can be, for example, a lip seal 300 made of an elastic material (elastomer). A stopper member 302 is provided between the valve body 110 and the motor housing 112, which contacts the valve body 110 to determine the fully open position of the valve body 110. When the valve body 110 moves in the opening direction, the lip seal 300 contacts the valve body 110 before the stopper member 302 contacts the valve body 110 to seal the periphery of the insertion hole 125 (Fig. 10). The stopper member 302 has rigidity, while the lip seal 300 has low rigidity in terms of material or structure. The stopper member 302 may be in the form of a ring, or may be in the form of a plurality of point-like or arc-like stopper members that are discretely arranged around the insertion hole 125. As another embodiment, a lip seal 304 may be attached to the valve body 110, as shown in FIG.

[0039] 13 to 15, in another embodiment, the elastic seal member can be in the form of, for example, O-rings 306, 308 formed from an elastic material, or bellows (elastic bellows) 310 formed from an elastic material. In this case, too, the elastic seal member can be attached to motor housing 112 like O-ring 306 in Fig. 13, or can be attached to valve body 110 like O-ring 308 in Fig. 14. Although not shown, a stopper member may be formed on valve body 110 instead of motor housing 112.

[0040] The lip seal 300 does not seal when the valve body 110 is in the closed position, and only when the valve body 110 moves in the opening direction and comes into contact with the lip seal 300 does it perform its sealing function. However, since the valve body 110 is held in the fully open position when the engine is stopped, even if the heat generated by the step motor 108 subsides and the motor housing 112 becomes negative pressure, the periphery of the insertion hole 125 is sealed, and moist air is not drawn into the motor housing 112. If the shaft is always covered with a bellows regardless of the position of the valve body 110, when the pressure inside the sealed housing fluctuates, the bellows is also loaded through the gap around the insertion hole 125, and there is a high possibility that cracks will occur. Even if the bellows does not crack, the step motor 108 needs to be powerful to overcome pressure changes and move the valve body 110, which increases costs. However, when the diaphragm 200 as described above is provided, it is possible to omit the stopper member 302, but it is more effective to provide the stopper member 302 as well. Conversely, when the stopper member 302 is provided, it is possible to omit the diaphragm 200, but it is more effective to also provide the diaphragm 200.

[0041] By rotating the step motor 108 in the open direction while the valve body 110 is in contact with the stopper member 302 to cause a step-out, the ISC valve 51 can be initialized with the fully open position of the valve body 110 as a reference. If the stopper member 302 is not present and the fully open position is held by only an elastic seal member such as a rubber sheet, the following problems may occur. First, if the elastic material of the elastic seal member is hard (has a large elastic modulus), the elastic seal member will hardly follow even if the step motor 108 steps out, and the sealing function may not be exerted. In order to move the valve body 110 to the fully open position without being defeated by the elastic seal member, for example, the step motor 108 needs to be made strong, which increases the cost. Conversely, if the elastic material of the elastic seal member is soft, when the valve body remains in the fully open position for a long time when the engine is stopped, the elastic seal member will be held in a greatly deformed state, and the material will become worn out and lose its restoring force. In contrast, by defining the fully open position with stopper member 302 as in the above embodiment, even if the elastic seal member is made sufficiently soft in the form of lip seal 300 or the like, lip seal 300 is not compressed to its limit and does not become worn out. Also, when initializing ISC valve 51 at the fully open position, even if valve element 110 returns slightly in the closing direction due to loss of synchronization, lip seal 300 follows and does not lose its sealing function.

[0042] Although various embodiments have been described above, the present technology is not limited to these embodiments, and various modifications, improvements, additions, and omissions can be made by those skilled in the art. [Explanation of symbols]

[0043] 1 Throttle device 2 Throttle body 6 Bore forming part 7 Main passage (bore) 9 Throttle shaft 12, 13 Elastic sealing member 14 Throttle valve 26 IDU coupling part 26a Mating surface 28 Entrance hole 30 exit hole 33 Valve seat 37 Passage groove 42 Through hole 50 IDU Body 50a mating surface 51 ISC valve 58 Storage unit 60 IDU Cover 68 Meat Stealing Department 70 Bypass Passage 72 Motor fitting part 75 Flange part 108 Step Motor 110 Valve body 112 Motor housing 125 Insertion hole 127 Shaft 129 Screw shaft 133 Sealing surface 136 Nut 138 Spring 180 Gasket 200 Diaphragm 202 Outer frame 210 Communication hole 220 Space 230 Container 232 Bellows 234 Connecting Pipe 300, 304 Lip seal 302 Stopper member 306, 308 O-ring 310 Bellows

Claims

1. A throttle device, comprising: a body member in which a main passage having a throttle valve and a bypass passage that bypasses the throttle valve are formed; a valve body that opens and closes the bypass passage; an actuator that moves the valve body via a shaft; a housing that is disposed in a receiving portion formed in the body member and receives the actuator; an insertion hole formed in the housing and through which the shaft is inserted; a pressure fluctuation suppressing means for suppressing pressure fluctuations in the accommodation portion.

2. 2. The throttle device of claim 1, The pressure fluctuation suppressing means is a throttle device having a diaphragm disposed facing the bypass passage.

3. The throttle device of claim 2, The body member includes a first body member forming the main passage and a second body member forming the accommodation portion, the bypass passage is formed between the first body member and the second body member, and the diaphragm is disposed in a recessed portion of the second body member facing the bypass passage, The pressure fluctuation suppressing means is a throttle device having a communication hole that communicates between the recessed portion and the housing portion.

4. 2. The throttle device of claim 1, a seal member is provided around the insertion hole to come into contact with the valve body or the housing when the valve body moves in an opening direction to seal the insertion hole; the actuator comprises a stepper motor; a stopper member is provided between the valve body and the housing, the stopper member being adapted to come into contact with the valve body or the housing to determine a fully open position of the valve body; a throttle device in which, when the valve body moves in an opening direction, the seal member comes into contact with the valve body or the housing to seal the insertion hole before the stopper member comes into contact with the valve body or the housing.

5. A throttle device, comprising: a body member in which a main passage having a throttle valve and a bypass passage that bypasses the throttle valve are formed; a valve body that opens and closes the bypass passage; a step motor that moves the valve body via a shaft; a housing that is disposed in a receiving portion formed in the body member and that receives the step motor; an insertion hole formed in the housing and through which the shaft is inserted; a seal member disposed around the insertion hole and contacting the valve body or the housing when the valve body moves in an opening direction to seal the insertion hole; a stopper member is provided between the valve body and the housing, the stopper member being adapted to abut against the valve body or the housing to determine a fully open position of the valve body; a throttle device in which, when the valve body moves in an opening direction, the seal member comes into contact with the valve body or the housing to seal the insertion hole before the stopper member comes into contact with the valve body or the housing.

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