JP2021113594A - Valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve device capable of suppressing submersion of an electric circuit in a casing.
A valve device is for driving a valve body connected to a valve box portion 41 in which a gas flow path containing water vapor flows, a valve body arranged in the gas flow path, and the valve body. A water tank 44 that is airtightly connected to the drive shaft 43 and the valve box portion 41, into which the drive shaft 43 is inserted and stores the electric circuit 56, and a water tank that is connected to the bottom of the casing 44 to store condensed water. A drainage port 63 provided in the water storage tank 62 for discharging condensed water, and a check valve 64 for drainage provided in the drainage port 63 are provided.
[Selection diagram] Fig. 3

Description

The present disclosure relates to a valve device used in a gas passage through which a gas containing water vapor flows.

The EGR (Exhaust Gas Recirculation) valve includes a valve body and a motor for driving the valve body. The valve body is arranged in the EGR passage and the motor is arranged outside the EGR passage.

Japanese Unexamined Patent Publication No. 2004-162609 Japanese Unexamined Patent Publication No. 2013-194547 Japanese Unexamined Patent Publication No. 2019-7388

By the way, engine exhaust gas (hereinafter referred to as exhaust gas) flows in the EGR passage. Further, the air in the casing of the motor repeats thermal expansion and contraction as the motor temperature rises and falls. Therefore, when the air in the casing is thermally shrunk, the exhaust gas in the EGR passage is sucked into the casing of the motor, etc., and then the casing or the like is further cooled to condense the water vapor contained in the exhaust gas into the casing or the like. Condensed water may be generated. Then, when the condensed water is accumulated, the electric circuit in the casing may be submerged.

Further, such condensed water may be generated not only in the EGR valve but also in the whole valve device used in the gas passage through which the gas containing water vapor flows.

Further, in the case of a valve device in which a gearbox is provided between the motor and the valve body and an electric circuit is housed in the casing of the gearbox, condensed water is accumulated in the casing by the same operation as described above, and the inside of the casing is contained. The electrical circuit may be submerged.

Therefore, the present disclosure was conceived in view of such circumstances, and an object thereof is to provide a valve device capable of suppressing submersion of an electric circuit in a casing.

According to one aspect of the present disclosure
The valve box part where the gas flow path through which the gas containing water vapor flows is formed,
A valve body arranged in the gas flow path and
A drive shaft connected to the valve body and for driving the valve body,
A casing that is connected to the valve box portion, the drive shaft is inserted, and the electric circuit is stored.
A water tank connected to the bottom of the casing to store condensed water,
A drainage port provided in the water tank for discharging condensed water,
A check valve for drainage provided at the drainage port and
A valve device is provided that comprises.

Preferably, the drainage port is provided in the lower part of the water storage tank, and the water storage tank is provided with a drainage port cover that covers the drainage port.

Preferably, the water storage tank or the casing is provided with an intake port for taking in outside air, and an intake check valve provided in the intake port.

Preferably, the intake port is provided in the upper part of the water storage tank, and the water storage tank is provided with an intake port cover that covers the intake port.

Preferably, the casing is composed of an outer shell of a motor that drives the valve body, and the drive shaft is composed of a rotation shaft of the motor.

Further, the casing may be composed of an outer shell of a gearbox, and the drive shaft may be composed of a rotation shaft of a gear housed in the casing.

According to the above aspect, it is possible to prevent the electric circuit in the casing from being submerged.

It is a schematic explanatory drawing of an internal combustion engine. It is a schematic top view of the EGR valve. It is an enlarged side sectional view of the main part of the EGR valve which concerns on one Embodiment of this disclosure. It is a schematic rear sectional view of the intake throttle valve which concerns on another embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, each direction of front, rear, left, right, up and down in the embodiment described later refers to each direction of the vehicle. However, each direction in the present embodiment is used for convenience of explanation, and represents a relative positional relationship between the members described later.

FIG. 1 is a schematic explanatory view of an internal combustion engine (engine) 1 according to the present disclosure. The engine 1 is a multi-cylinder compression ignition type internal combustion engine mounted on a vehicle, that is, a diesel engine. The illustrated example shows an in-line 4-cylinder engine, but the cylinder arrangement type, the number of cylinders, and the like of the engine are arbitrary.

The engine 1 includes an engine main body 2, an intake passage 3 and an exhaust passage 4 connected to the engine main body 2, and a fuel injection device 5. The engine body 2 includes structural parts such as a cylinder head, a cylinder block, and a crankcase, and movable parts such as a piston, a crankshaft, and a valve housed therein.

The fuel injection device 5 includes a common rail type fuel injection device, and includes a fuel injection valve, that is, an injector 7, provided in each cylinder, and a common rail 8 connected to the injector 7. The injector 7 injects fuel directly into the cylinder 9. The common rail 8 stores the fuel injected from the injector 7 in a high pressure state.

The intake passage 3 is mainly defined by an intake manifold 10 connected to the engine body 2 (particularly a cylinder head) and an intake pipe 11 connected to the upstream end of the intake manifold 10. The intake manifold 10 distributes and supplies the intake air sent from the intake pipe 11 to the intake ports of each cylinder. The intake pipe 11 is provided with an air cleaner 12, a compressor 14C of a turbocharger 14, an intercooler 15, and an electronically controlled intake throttle valve 16 in this order from the upstream side.

The exhaust passage 4 is mainly defined by an exhaust manifold 20 connected to the engine body 2 (particularly a cylinder head) and an exhaust pipe 21 arranged on the downstream side of the exhaust manifold 20. The exhaust manifold 20 collects the exhaust gas sent from the exhaust port of each cylinder. A turbine 14T of a turbocharger 14 is provided between the exhaust pipe 21 or the exhaust manifold 20 and the exhaust pipe 21. An exhaust gas purification device (not shown) is provided in the exhaust pipe 21 on the downstream side of the turbine 14T.

Further, the engine 1 includes a high-pressure EGR device 30 and a low-pressure EGR device 34.

The high-pressure EGR device 30 and the low-pressure EGR device 34 return the exhaust gas in the exhaust passage 4 to the intake passage 3.

The high-pressure EGR device 30 includes a high-pressure EGR passage 31, a high-pressure EGR cooler 32, and a high-pressure EGR valve 33. The high-pressure EGR passage 31 connects the intake manifold 10 and the exhaust manifold 20. The high-pressure EGR cooler 32 is provided in the high-pressure EGR passage 31. The high-pressure EGR valve 33 is provided in the high-pressure EGR passage 31 on the downstream side of the high-pressure EGR cooler 32.

The low-pressure EGR device 34 includes a low-pressure EGR passage 35, a low-pressure EGR cooler 36, and a low-pressure EGR valve 37.

The low-pressure EGR passage 35 connects the exhaust passage 4 on the downstream side of the turbine 14T and the intake passage 3 on the upstream side of the compressor 14C.

The low pressure EGR cooler 36 is provided in the low pressure EGR passage 35. The low-pressure EGR valve 37 is provided in the low-pressure EGR passage 35 on the downstream side of the low-pressure EGR cooler 36.

The high-pressure EGR valve 33 and the low-pressure EGR valve 37 are composed of a valve device 40 (see FIG. 2) having a similar structure. Therefore, the valve device 40 constituting the high-pressure EGR valve 33 will be described below, and the valve device 40 constituting the low-pressure EGR valve 37 will be omitted.

As shown in FIGS. 2 and 3, the valve device 40 constituting the high-pressure EGR valve 33 is a poppet valve. The valve device 40 has a valve box portion 41 in which a passage hole 45 (gas flow path) communicating with the high-pressure EGR passage 31 is formed, a valve body 42 arranged in the passage hole 45, and one end of the valve body 42. It includes a drive shaft 43 that is connected to drive the valve body 42, and a casing 44 that is airtightly connected to the valve box portion 41 and into which the other end of the drive shaft 43 is inserted.

The valve box portion 41 is formed in a block shape extending in the front-rear direction. A crank-shaped passage hole 45 is formed at the rear end of the valve box portion 41. The passage hole 45 includes a first side hole portion 46 extending horizontally from the left end of the valve box portion 41 to the central portion in the left-right direction, and a central portion in the left-right direction from the right end of the valve box portion 41 behind the first side hole portion 46. A central hole 47 extending horizontally and extending in the front-rear direction at the center of the valve box 41 in the left-right direction to connect the first side hole 46 and the second side hole 47. A unit 48 is provided. A valve seat 49 for seating the valve body 42, which will be described later, in a liquid-tight manner is provided in the central hole portion 48. Further, a fitting hole 50 for fitting the casing 44, which will be described later, is formed at the front end portion of the valve box portion 41. Further, an insertion hole 51 for inserting the drive shaft 43 is formed in the valve box portion 41 between the fitting hole 50 and the first side hole portion 46. The insertion hole 51 is provided with a sealing member 52 for sealing between the valve box portion 41 and the drive shaft 43. The valve box portion 41 is not limited to this. For example, the passage hole 45 may include a central hole portion 48, and the shape and extension direction of the first side hole portion 46 and the second side hole portion 47 are arbitrary.

The casing 44 is composed of an outer shell of a motor 53 that drives the valve body 42. The drive shaft 43 is composed of a rotation shaft of the motor 53. That is, the casing 44 and the drive shaft 43 are a part of the motor 53.

The motor 53 includes a casing 44, a drive shaft 43, a stator 54, and a rotor 55.

The casing 44 is formed in a cylindrical shape with both ends closed. The rear end portion of the casing 44 is liquid-tightly fitted and connected to the fitting hole 50 of the valve box portion 41. Further, a circuit board (printed circuit board) 56, which is an electric circuit for driving the motor 53, is provided in the casing 44. Specifically, a space S is formed in the casing 44 on the front side of the rotor 55, which will be described later, and the circuit board 56 is arranged upright in the space S. Further, a connector 57 connected to the circuit board 56 is provided on the front end side of the casing 44. A control device (not shown) is connected to the connector 57. That is, a control circuit for driving the motor 53 is formed on the circuit board 56. The motor 53 is not limited to this. The motor 53 may be of another type as long as an electric circuit (not shown) is accommodated in the space S. Further, the electric circuit is not limited to the circuit board 56. For example, the electric circuit may be formed by connecting a semiconductor element or the like with an electric wire or the like. Further, the space S may be formed at another position in the casing 44.

The stator 54 is composed of an electromagnet, and a plurality of stators 54 are provided along the inner peripheral surface of the casing 44.

The rotor 55 is rotatably provided around an axis extending in the front-rear direction at a position surrounded by the stator 54 in the casing 44. The rotor 55 includes an iron core 58 formed in a cylindrical shape and a permanent magnet 59 provided on the outer periphery of the iron core 58. A female screw 60 is formed on the inner peripheral surface of the iron core 58.

Further, the front end portion of the drive shaft 43 is housed in the iron core 58. At the front end of the drive shaft 43, a male screw 61 screwed with the female screw 60 is formed. Further, the drive shaft 43 is spline-engaged (not shown) with the valve box portion 41, and is movable in the axial direction with respect to the valve box portion 41 and cannot rotate. The drive shaft 43 reciprocates in the front-rear direction with respect to the casing 44 when the rotor 55 rotates in the forward or reverse direction. The rotor 55 is provided with a permanent magnet 59, and the stator 54 is composed of an electromagnet, but the present invention is not limited to this. The stator 54 may be composed of a permanent magnet 59, and the rotor 55 may include an electromagnet.

The valve body 42 is formed in a disk shape coaxial with the drive shaft 43, and is provided at the rear end portion of the drive shaft 43. The valve body 42 is separated from the valve seat 49 by moving the drive shaft 43 rearward to open the valve device 40. Further, the valve body 42 is seated on the valve seat 49 by moving the drive shaft 43 forward to close the valve device 40.

By the way, the motor 53 generates heat when driven and is cooled by receiving a running wind. Further, the motor 53 has a structure that is generally sealed so that rainwater, water at the time of car washing, and the like do not enter from the outside. Therefore, when the temperature of the motor 53 drops, the air in the casing 44 contracts and the pressure in the casing 44 drops. Further, exhaust gas including water vapor due to combustion flows through the high-pressure EGR passage 31, and only the seal member 52 prevents the exhaust gas from entering the motor 53. Therefore, when the air in the casing 44 contracts and the pressure in the casing 44 drops, the exhaust gas in the high-pressure EGR passage 31 may pass through the seal member 52 and enter the casing 44. Further, when the exhaust gas that has entered the casing 44 is cooled, condensed water may be generated in the casing 44. Then, the electric substrate in the casing 44 may be submerged due to repeated generation of condensed water.

Therefore, the valve device 40 according to the present embodiment has a water storage tank 62 connected to the bottom of the casing 44 for storing condensed water, a drain port 63 provided in the water storage tank 62 for discharging condensed water, and drainage. It is provided with a drainage check valve 64 provided at the mouth 63. As a result, the condensed water generated in the casing 44 can be discharged to the water storage tank 62 outside the casing 44 while maintaining the airtightness of the casing 44. Then, when the condensed water is accumulated in the water storage tank 62, the condensed water can be discharged from the water storage tank 62 to the outside.

At the bottom of the casing 44, a water channel 65 for guiding the condensed water generated in the space S to the water storage tank 62 is formed. The water channel 65 is formed by being bent in a plurality of stages in a labyrinth-like manner. Further, the inlet 65a of the water channel 65 is formed so as to be displaced in the horizontal direction from directly below the circuit board 56. As a result, the condensed water in the water storage tank 62 is suppressed from jumping into the casing 44 due to vibration or the like, and even if the condensed water in the water storage tank 62 jumps up from the inlet 65a, the condensed water is applied to the circuit board 56. Is suppressed. Further, an inclined surface 66 for guiding condensed water to the inlet 65a of the water channel 65 may be formed at the bottom of the casing 44. The water storage tank 62 is formed so as to extend vertically, and its upper end is liquidtightly connected to the bottom of the casing 44.

The drain port 63 is provided at the lower end of the water storage tank 62. Specifically, the drainage port 63 is formed in a tubular shape, and is provided at the lower end of the peripheral side surface portion of the water storage tank 62 so as to extend rearward. Further, the water storage tank 62 is provided with a drainage port cover 67 that covers the drainage port 63. The drainage port cover 67 is formed so as to cover the drainage port 63 from above, left, right, and rear. The drainage port 63 is formed in a tubular shape extending rearward, but the drainage port 63 is not limited to this. Further, it is preferable that the outlet 63a of the drainage port 63 is directed in the horizontal direction. For example, the outlet 63a of the drainage port 63 may be directed downward. In this case, the drainage port cover 67 may include a portion that covers at least the outlet 63a of the drainage port 63 from below. As a result, rainwater or the like splashed up by the tire is suppressed from directly entering the drain port 63.

The drainage check valve 64 is formed so as to allow a flow in the direction of discharging from the water storage tank 62 and to stop the flow in the direction opposite to the flow. The drainage port cover 67 and the check valve 64 for drainage prevent water flowing down from above during car washing, rainwater splashed up by tires, and the like from entering the water storage tank 62 from the drainage port 63. Further, the drainage check valve 64 is set to open when a preset first set pressure acts from the inside of the water storage tank 62. The first set pressure is set to open when the motor is warmed up and the internal temperature of the motor rises and the internal pressure rises. It is possible to prevent the condensed water from being discharged and accumulated when the condensed water is generated and then warmed up and the internal pressure is increased.

Further, the valve device 40 is provided in the water storage tank 62, and includes an intake port 68 for taking in outside air and an intake check valve 69 provided in the intake port 68.

The intake port 68 is provided in the upper part of the water storage tank 62. Specifically, the intake port 68 is formed in a tubular shape extending forward from the upper part of the water storage tank 62. Further, the water storage tank 62 is provided with an intake port cover 70 that covers the intake port 68. The intake port cover 70 is formed so as to cover the intake port 68 from above, left, right, and front. The intake port 68 is formed in a tubular shape extending forward, but the present invention is not limited to this. Further, it is preferable that the intake port 68 has its inlet 68a directed in the horizontal direction. For example, the inlet 68a of the intake port 68 may be directed upward. In this case, the intake port cover 70 may include a portion that covers the inlet 68a of the intake port 68 from at least above. As a result, it is suppressed that rainfall enters the intake port 68 directly.

The intake check valve 69 is formed so as to allow a flow in the direction of flowing into the water storage tank 62 and to stop the flow in the direction opposite to the flow. Further, the intake check valve 69 is set to open when the differential pressure when the pressure in the casing 44 is subtracted from the atmospheric pressure becomes larger than the positive second set pressure. Specifically, the second set pressure is set to a value such that the intake check valve 69 does not open when the rainwater or the like splashed up by the tire hits the intake check valve 69. As a result, it is possible to prevent the negative pressure in the casing 44 from becoming excessive while maintaining the airtightness of the casing 44. As a result, it is possible to prevent the exhaust gas in the passage hole 45 from being sucked into the casing 44. Although the intake port 68 is provided in the water storage tank 62, it may be provided in the casing 44.

Next, the operation of this embodiment will be described.

When condensed water is generated in the casing 44, the condensed water is guided to the water channel 65 along the inclined surface 66. The condensed water guided to the water channel 65 flows down to the water tank 62 and is stored in the water tank 62.

When the condensed water collects in the water storage tank 62 and the pressure acting on the drainage check valve 64 becomes equal to or higher than the first set pressure, the drainage check valve 64 opens. It is possible to prevent the condensed water from being discharged and accumulated when the condensed water is generated and then warmed up and the internal pressure is increased.

Further, when the vehicle equipped with the valve device 40 shakes greatly due to traveling on a rough road or the like, the condensed water in the water storage tank 62 may also shake greatly. However, the casing 44 and the water storage tank 62 are connected to each other via a water channel 65 that bends in a plurality of stages in a labyrinth-like manner. Therefore, even if the condensed water in the water storage tank 62 shakes greatly, it is suppressed from jumping into the casing 44. Further, even if the condensed water in the water storage tank 62 jumps up into the casing 44, the inlet 65a of the water channel 65 is formed so as to be displaced in the horizontal direction from directly below the circuit board 56. Therefore, it is possible to prevent the condensed water splashed from the inlet 65a from being applied to the circuit board 56.

Further, when the air in the casing 44 contracts due to the motor 53 being cooled by the traveling wind or the like, the pressure in the casing 44 decreases. Then, when the pressure in the casing 44 becomes lower than the second set pressure with respect to the atmospheric pressure, the intake check valve 69 opens. As a result, the magnitude of the negative pressure inside the casing 44 is kept below the second set pressure, and the exhaust gas in the passage hole 45 can be suppressed from entering the casing 44. Therefore, the generation of condensed water in the casing 44 can be suppressed.

Although the embodiments of the present disclosure have been described in detail above, the present disclosure may also include the following other embodiments.

(1) Although the valve device 40 constituting the EGR valve 33 has been described, the valve device 40 is not limited to the EGR valve. The valve device 40 can be widely applied to a valve in which condensed water may be generated, that is, a valve used in a flow path through which a gas containing water vapor flows.

(2) The casing 44 is composed of the outer shell of the motor 53, and the drive shaft 43 is composed of the rotating shaft of the motor 53, but the present invention is not limited to this. For example, as shown in FIG. 4, the casing 71 is composed of the outer shell of the gearbox 72 in which the circuit board 56 is housed, and the drive shaft 73 is the rotation shaft of the output gear 74 housed in the casing 71. It may be configured. The valve device 75 in this case will be described. The same components as described above are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIGS. 1 and 4, the valve device 75 constitutes the intake throttle valve 16 and is a butterfly valve. The valve device 75 has a valve box portion 76 in which a passage hole (gas flow path) 84 communicating with the intake passage 3 is formed, a valve body 77 arranged in the passage hole 84, and one end of the valve body 77. It includes a drive shaft 73 that is connected to drive the valve body 77, and a casing 71 that is airtightly connected to the valve box portion 76 and into which the other end of the drive shaft 73 is inserted.

The valve box portion 76 includes an intake pipe portion 78 extending in the front-rear direction and a shaft accommodating portion 79 extending from the center of the intake pipe portion 78 in the front-rear direction to the left. The intake pipe portion 78 is formed in a tubular shape and defines a passage hole 84. The shaft accommodating portion 79 is formed in a tubular shape, and the base end is connected to the intake pipe portion 78 and the tip end is connected to the casing 71. A drive shaft 73, which will be described later, is penetrated and accommodated in the shaft accommodating portion 79 in the left-right direction. Further, in the shaft accommodating portion 79, a bearing (not shown) that rotatably supports the drive shaft 73 is provided, and a seal member for sealing between the valve box portion 76 and the drive shaft 73 (FIG. Not shown) is provided.

The valve body 77 is formed in a disk shape having an outer diameter substantially the same as the inner diameter of the intake pipe portion 78. The drive shaft 73 is formed so as to extend in the left-right direction. The right end portion of the drive shaft 73 is arranged in the intake pipe portion 78 and intersects the central axis x of the intake pipe portion 78. A valve body 77 is attached to the right end of the drive shaft 73 with its center positioned on the central shaft x. The valve body 77 closes the intake pipe portion 78 so that the opening degree can be adjusted by rotating the drive shaft 73. Further, the left end portion of the drive shaft 73 extends into the casing 71 described later. An output gear 74 is integrally provided at the left end of the drive shaft 73.

The casing 71 is composed of the outer shell of the gearbox 72. The gearbox 72 includes a casing 71, an output gear 74, an intermediate gear 80, an input gear 81, and a motor 82. The casing 71 is formed in a vertically long box shape. The casing 71 is integrally provided at the left end of the shaft accommodating portion 79. The output gear 74 is housed in the casing 71. The motor 82 is integrally provided in the casing 71 above the drive shaft 73. The rotating shaft 83 of the motor 82 extends into the casing 71. The input gear 81 is composed of a pinion gear and is provided on the rotating shaft 83 of the motor 82. The input gear 81 is housed in the casing 71. The intermediate gear 80 is rotatably provided in the casing 71, and transmits the rotational driving force of the input gear 81 to the output gear 74. Further, the circuit board 56 is stored in the casing 71.

A water storage tank 62 is provided at the bottom of the casing 71, and a water channel 65 for guiding the condensed water generated in the casing to the water storage tank 62 is formed. Further, the water storage tank 62 is provided with a drain port 63, a drain port cover 67, an intake port 68, and an intake port cover 70. Further, the drain port 63 is provided with a check valve 64 for drainage. The intake port 68 is provided with an intake check valve 69.

As described above, even if the casing 71 is composed of the outer shell of the gearbox 72 and the drive shaft 73 is composed of the rotating shaft of the output gear 74 housed in the casing 71, the circuit in the casing 71 is formed. It is possible to prevent or suppress the substrate 56 from being submerged in water.

31 High-pressure EGR passage (gas passage)
40 Valve device 41 Valve box 42 Valve body 43 Drive shaft 44 Casing 56 Circuit board (electric circuit)
62 Water tank 63 Drainage port 64 Check valve for drainage

Claims (6)

The valve box part where the gas flow path through which the gas containing water vapor flows is formed,
A valve body arranged in the gas flow path and
A drive shaft connected to the valve body and for driving the valve body,
A casing that is connected to the valve box portion, the drive shaft is inserted, and the electric circuit is stored.
A water tank connected to the bottom of the casing to store condensed water,
A drainage port provided in the water tank for discharging condensed water,
A check valve for drainage provided at the drainage port and
A valve device characterized by being equipped with. The drainage port is provided at the bottom of the water tank and is provided.
The valve device according to claim 1, wherein the water storage tank is provided with a drainage port cover that covers the drainage port. An intake port provided in the water tank or the casing for taking in outside air, and
The valve device according to claim 1 or 2, further comprising an intake check valve provided at the intake port. The intake port is provided in the upper part of the water tank.
The valve device according to claim 3, wherein the water storage tank is provided with an intake port cover that covers the intake port. The casing is composed of an outer shell of a motor that drives the valve body.
The valve device according to any one of claims 1 to 4, wherein the drive shaft is composed of a rotating shaft of the motor. The casing is composed of the outer shell of the gearbox.
The valve device according to any one of claims 1 to 4, wherein the drive shaft includes a rotation shaft of a gear housed in the casing.

Images