JP2023041392A - valve structure - Google Patents

Abstract

To provide a valve structure which can remove deposits adhering to a valve while suppressing reduction in a flow rate of gas which flows in a passage.SOLUTION: A valve structure 10 comprises: a valve 20 which opens and closes a passage 13 in which gas flows with a valve disc 24 disposed at a tip of a valve stem 22; and a removal member 40 which is attached to a housing 12 which forms the passage 13, makes contact with the valve disc 24 along with movement of the valve 20 in a closing direction, and removes deposits adhering to a surface of the valve disc 24. The removal member 40 is formed in a shape of a plate extending along the valve stem 22, with a tip part 40a that makes contact with the valve disc 24 having a shape conforming to a surface shape of the valve disc 24. The valve 20 is rotated by a rotation mechanism 50 which rotates the valve 20 about the valve stem 22 with the tip part 40a of the removal member 40 in contact therewith.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a valve structure used for adjusting the flow rate of gas flowing through a passage.

An engine of a vehicle such as an automobile is provided with an EGR (exhaust gas recirculation) passage from the viewpoint of improving thermal efficiency. The EGR passage is a passage for recirculating part of the exhaust gas from the exhaust passage to the intake passage, and is provided with a valve for adjusting the amount of recirculated exhaust gas.

Exhaust gas flowing through the EGR passage contains foreign substances such as soot, and these foreign substances accumulate as deposits on the surface of the valve. If the amount of deposited deposits increases, the flow rate characteristics of the exhaust gas will change, leading to a decrease in performance and engine failures.

For example, Patent Literature 1 describes a valve structure in which, in a valve installed in an EGR passage, the shape of a valve seat on which the valve is seated is improved, and deposits on the valve surface are removed by this valve seat. In this valve structure, in a housing forming an EGR passage, an annular valve seat on which a valve disc is seated is arranged coaxially in the axial direction of the valve stem. of valve seats. The first valve seat functions as a deposit removing section, and is formed so that the outer diameter can be expanded and contracted. Contact. The second valve seat functions as an airtight seal, is fixed so that the outer diameter is always constant, and is in close contact with the valve disc in the closed position of the valve.

In the valve structure described in Patent Document 1, while the valve is moving in the closing direction, the valve disc contacts the first valve seat and moves to the valve closing position while expanding the diameter of the first valve seat. do. At this time, deposits adhering to the surface of the valve disc are scraped off and removed by the first valve seat.

JP 2018-123725 A

In the valve structure described above, in order to obtain the effect of removing deposits, it is necessary for the valve to come into contact with the first valve seat, which is the deposit removing member, before the valve reaches the closed valve position. Since the first valve seat is arranged over the entire circumference of the valve disc, the EGR passage is closed when the valve contacts the first valve seat while it is moving in the closing direction.

In order to accurately manage the flow rate of the exhaust gas, the timing at which the EGR passage is closed must coincide with the timing at which the first valve seat comes into contact with the valve. The flow rate is controlled based on the timing at which the valve is in the closed position. Therefore, the conventional valve structure has a problem that the actual flow rate of the exhaust gas is lowered.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a valve structure capable of removing deposits adhering to the valve while suppressing a decrease in the actual gas flow rate.

In order to achieve the above object, one embodiment of the present invention provides a valve that opens and closes a passage through which gas flows by means of a valve disc provided at the tip of a valve stem; a removing member that contacts the valve disc as it moves in the closing direction and removes deposits adhering to the surface of the valve disc, wherein the removing member extends along the valve stem. A plate-like tip portion that contacts the valve disc has a shape that conforms to the surface shape of the valve disc, and the valve is in contact with the tip portion of the removal member, and the valve stem is attached to the valve stem. is rotated by a rotation mechanism that rotates the valve around

Further, in one embodiment of the present invention, in the valve structure, a plate-like member is attached to the housing and has a tip portion contacting the valve to apply a rotational force to the valve, and the removing member It is characterized by being constituted by a plate-shaped member.

In one embodiment of the present invention, in the valve structure, the rotating mechanism includes a plurality of ratchet teeth provided along the entire circumference of the valve so as to surround the valve stem, and a ratchet tooth attached to the housing. and a ratchet pawl that engages with the ratchet teeth.

In one embodiment of the present invention, in the valve structure, the removal member is composed of a first leaf spring whose distal end side region is elastically bent, and the ratchet pawl is arranged along the valve stem. The first leaf spring and the second leaf spring are formed at the distal end of a second leaf spring that extends in the direction of the distal end and elastically bends in the distal end side region. It is characterized by bending to.

In one embodiment of the present invention, in the valve structure, the first leaf spring and the second leaf spring are integrally formed.

According to the valve structure according to the present invention, it is possible to remove deposits adhering to the valve while suppressing a decrease in the actual gas flow rate.

1 is a schematic explanatory diagram of an engine to which a valve structure that is an embodiment of the present invention is applied; FIG. Fig. 3 is a schematic diagram of a valve structure; It is an explanatory view showing an open state of the valve. FIG. 4 is an explanatory diagram showing a closed state of a valve; 4 is a cross-sectional view taken along line AA of FIG. 3; FIG. It is explanatory drawing of a ratchet mechanism. FIG. 5 is an explanatory view showing a bent state of a first leaf spring that constitutes the removing member; FIG. 5 is an explanatory view showing a bent state of a second leaf spring that constitutes a ratchet pawl; FIG. 10 is an explanatory diagram showing another example of the removing member;

FIG. 1 is a schematic explanatory diagram of an engine 1 to which a valve structure 10 according to one embodiment of the invention is applied. The engine 1 is mounted on a vehicle such as an automobile, and includes an engine body 2 having a combustion chamber, an intake passage 4, an exhaust passage 6, an EGR (exhaust gas recirculation) passage 8, and a turbocharger 9. . The intake passage 4, the exhaust passage 6 and the EGR passage 8 are formed by an intake pipe, an exhaust pipe and an EGR pipe, respectively. In this embodiment, a valve structure 10 having a deposit removing function is applied to the EGR valve 20 arranged in the EGR passage 8 .

The engine body 2 can be a small engine with a small displacement, a large engine with a large displacement, or the like, and the engine type can be, for example, a horizontally opposed type, an in-line type, a V type, or the like.

The turbocharger 9 is a supercharger including a compressor 9A, a turbine 9B, and the like. The compressor 9A is a centrifugal compressor that compresses fuel air (fresh air) that the engine body 2 takes in. The turbine 9B uses the exhaust energy of the engine 1 to drive the compressor 9A.

The intake passage 4 is a flow passage for fresh air introduced into the engine body 2 . The intake passage 4 is provided with an air cleaner 4A, an air flow meter 4B, a compressor 9A of the turbocharger 9, an intercooler 4C, and a throttle valve 4D in this order from the upstream side. An intake manifold 5</b>A, which is a branch pipe for distributing fresh air to the intake ports of the cylinders of the engine body 2 , is provided at the end of the intake passage 4 on the side of the engine body 2 .

The air cleaner 4A filters outside air sucked into the intake passage 4 to remove dust and the like. The airflow meter 4B detects the flow rate of fresh air passing through the intake passage 10 and transmits it to an engine control unit (hereinafter referred to as "ECU").

The intercooler 4C cools fresh air, which has been pressurized by the compressor 9A and heated to a high temperature, by exchanging heat with, for example, running wind or engine cooling water. The throttle valve 4D opens and closes the intake passage 4 according to an instruction from the EUC to control the flow rate of intake air.

The exhaust passage 6 is a flow passage for the exhaust discharged from the engine body 2 . At the end of the exhaust passage 6 on the side of the engine main body 2, an exhaust manifold 5B, which is a collecting pipe for joining the exhaust gases from the exhaust ports of the cylinders of the engine main body 2, is provided. The exhaust passage 6 is provided with a turbine 9B of the turbocharger 9, an exhaust gas treatment device 6A, and a muffler 6B in this order from the upstream side. Nitrogen oxides (NOx) are removed.

The EGR passage 8 is a passage through which part of the exhaust gas is extracted as EGR gas from between the exhaust manifold 5B and the turbine 9B or from the downstream side of the turbine 9B and introduced into the intake passage 4 . The EGR passage 8 communicates with the intake passage 4 downstream of the throttle valve 4D in the intake passage 4 and upstream of the intake manifold 5A. The EGR passage 8 is provided with an EGR cooler 8A and an EGR valve 20 in this order from the upstream side.

FIG. 2 is a schematic diagram of an EGR valve 20 having the valve structure 10 of this embodiment. In the following description, "EGR valve 20" is also simply called "valve 20". The valve 20 has a valve stem 22 that moves forward and backward in the axial direction, and a valve disc 24 that is connected and fixed to the tip of the valve stem 22 .

The valve structure 10 of this embodiment includes a valve 20, a housing 12 to which the valve 20 is attached, an actuator 19 for driving the valve 20, a removal member 40 for removing deposits, and a rotation mechanism 50 for rotating the valve 20. And prepare. The rotation mechanism 50 includes a ratchet mechanism for restricting the rotation direction of the valve 20 to one direction. Prepare.

The housing 12 has a passage 13 through which EGR gas flows. A gas introduction port 14 is formed on the upstream side of the passage 13 and a gas outflow port 15 is formed on the downstream side thereof. The gas introduction port 14 and the gas outflow port 15 are each connected to the EGR pipe while ensuring airtightness. In the example shown in FIG. 2, the passage 13 is bent in an L shape, and the gas introduction port 14 is formed at the lower end of the housing 12 .

A valve seat 18 is attached to the inner wall of the passageway 13 of the housing 12 on which the valve 20 is seated. The valve seat 18 is formed in an annular shape so as to be in contact with the peripheral portion of the valve disc 24 over the entire circumference.

The valve 20 can be made of, for example, a metal material such as iron-based metal. In this embodiment, the valve 20 is a poppet valve that opens and closes the passage 13 as the valve stem 22 moves forward and backward in the axial direction. Specifically, as shown in FIG. 3, when the valve 20 advances to the gas introduction port 14 side, the valve disk 24 is separated from the valve seat 18 and the passage 13 is opened. On the other hand, as shown in FIG. 4, when the valve 20 is retracted, the valve disk 24 contacts the seal member 18 over the entire circumference, and the passage 13 is closed. In this embodiment, a receiving member 17 that receives the biasing force of a coil spring 16 housed in the hollow portion of the housing 12 is attached to the valve stem 22. The biasing force of the coil spring 16 causes the valve 20 to move in the closing direction. is energized by The proximal end of the valve stem 22 is connected to an actuator 19 incorporated in the housing 12 , and the actuation of this actuator 19 moves the valve 20 in the opening direction against the biasing force of the spring 16 . Also, the valve stem 22 is rotatable around the central axis by means of a bearing member 26, and the valve disc 24 rotates as the valve stem 22 rotates.

The valve 20 is provided with a plurality of ratchet teeth 52 forming a ratchet mechanism. A plurality of ratchet teeth 52 are provided along the entire circumference of the valve 20 so as to surround the valve stem 22 . In this embodiment, as shown in FIGS. 5 and 6, ratchet teeth 52 are annularly formed in the connecting region 28 between the valve stem 22 and the valve disc 24 . Each ratchet tooth 52 protrudes in the axial direction of the valve stem 22 from the upper surface of the valve disc 24 toward the proximal end of the valve stem 22 .

The removing member 40 removes deposits adhering to the valve 20 and is composed of a plate-like member 30 attached to the housing 12 . In FIGS. 2 to 5, the plate member 30 is marked with dots for easy understanding.

The plate member 30 includes a base portion 31 fitted in a groove formed in the housing 12, a holding portion 32 extending from the base portion 31 toward the passage 13, a first bent portion 34 extending from the holding portion 32, and and a second bent portion 36 . As shown in FIGS. 3 to 5, the first bent portion 34 and the second bent portion 36 have a large plate width on the tip side of the plate-like member 30 due to the slits 35 formed in the plate-like member 30. It is a region separated into a wide region and a narrow region having a narrow plate width. The first bent portion 34 is a wide area formed radially outwardly of the bulb 20 , and the second bent portion 36 is a narrowed area formed radially inwardly of the bulb 20 . The plate-like member 30 can be made of, for example, a metallic material such as iron-based metal.

The first bent portion 34 and the second bent portion 36 respectively form a first leaf spring and a second leaf spring elastically bent with respect to the holding portion 32 . 7 and 8 show the bent state of the first leaf spring and the bent state of the second leaf spring, respectively. The first leaf spring and the second leaf spring are integrally formed via a holding portion 32, and as shown in FIGS. Bend in the opposite direction.

The removing member 40 is composed of the base portion 31 , the holding portion 32 and the first bending portion 34 of the plate-like member 30 . In this embodiment, one removal member 40 is provided for the valve 20 , and this removal member 40 is arranged outside the bend of the passage 13 with respect to the valve 20 . As shown in FIG. 3 , the removing member 40 is formed in a plate-like shape extending along the valve stem 22 by the plate-like member 30 , and the tip portion 40 a of the removing member 40 extends along the surface shape of the valve disc 24 . have a shape. In this embodiment, the tip portion 40 a is formed in an inclined shape along the umbrella shape of the upper surface of the valve disc 24 .

The first bent portion 34 of the removal member 40 is spaced apart from the valve disc 24 when the valve 20 is in the open position, as shown in FIG. The tip 40a of the removal member 40 contacts the valve disc 24 before the valve reaches the closed position.

The base portion 31 , the holding portion 32 and the second bending portion 36 (that is, the second plate spring) of the plate-like member 30 constitute a rotating mechanism 50 that imparts a rotating force to the valve 20 . A ratchet pawl 54 is formed at the tip of the second bent portion 36 .

As shown in FIG. 6 , the ratchet pawl 54 has a contact surface with the ratchet teeth 54 formed on an inclined surface along the tooth surfaces of the ratchet teeth 54 . The ratchet pawl 54 engages with the ratchet teeth 54 provided on the valve 22 to restrict the rotational direction of the valve 20 to one direction. In this embodiment, the valve 20 rotates about the valve stem 22 in the direction of arrow R in FIG. Regulate the direction of rotation so that it does not rotate in the same direction. In order to improve durability and wear resistance, the ratchet pawl 54 can be coated on its surface or made of a material having a higher strength than the plate member 30 .

In this embodiment, when the valve 20 is in the open position, the ratchet pawl 54 is disengaged from the ratchet teeth 52 and engaged with the ratchet teeth 52 while the valve 20 is moving in the closing direction. The length of the second leaf spring is set so as to After the ratchet pawl 54 is engaged, the valve 20 further moves in the closing direction so that the second bending portion 36 is elastically bent while imparting a rotational force to the valve 20 . The length of the second leaf spring may be adjusted so that the valve 20 is always engaged with the ratchet teeth 52 .

The operation of the valve structure 10 described above will now be described.

As shown in FIG. 3, when the valve 20 is in the open position, the tip 40a of the removal member 40, which is the first leaf spring, is separated from the valve disc 24. As shown in FIG. Also, the ratchet pawl 54 provided at the tip of the second leaf spring is separated from the ratchet teeth 52 and is in a non-engaged state. Side portions of the holding portion 32 and the second bent portion 36 of the plate-like member 30 constituting the second leaf spring are in contact with the peripheral surface of the valve stem 22 .

As the valve 20 moves in the closed direction from the open position, the ratchet pawl 54 engages the ratchet teeth 52 and the tip 40a of the removal member 40 contacts the valve disc 24 during the movement of the valve 20 .

When the valve 20 moves further in the closing direction, the second bent portion 36 of the second leaf spring bends with respect to the holding portion 32 as shown in FIG. forces act. Due to the biasing force of this second leaf spring and the regulation of the rotation direction by the ratchet mechanism, the valve 20 rotates in the direction of arrow R in FIG. 8 during movement in the closing direction. At this time, as shown in FIG. 7, the first bent portion 34 of the removing member 40 is bent in the opposite direction to the second bent portion 36 while the tip portion 40a is in contact with the upper surface of the valve disc 24. bends into As the valve 20 rotates while the tip 40 a of the removing member 40 is in contact with the valve disc 24 , the deposit adhering to the surface of the valve disc 24 is removed by the tip 40 a of the removing member 40 . scraped off and removed. In addition, deposits adhering to the peripheral surface of the valve stem 22 are also scraped off by the plate-shaped member 30 by rotating the valve stem 22 with the side portion of the plate-shaped member 30 in contact with the peripheral surface of the valve stem 22 . removed.

As shown in FIG. 4, when the valve 20 is moved to the closed position, the valve disc 24 is in close contact with the valve seat 18 to form an airtight seal.

As described above, in the valve structure 10 of the present embodiment, the distal end portion 40 of the removing member 40 comes into contact with the valve 20 as the valve 20 is moved to close, and the deposit adhering to the valve disc 24 can be removed. . The removing member 40 is formed in the shape of a thin plate extending in the axial and radial directions of the valve 20, and contacts only a part of the valve disk 24 in the circumferential direction, not the entire circumference. Even after 40 contacts valve 20, EGR gas flows through passage 13 until valve 20 moves to the closed position. As a result, even when the flow rate of EGR gas is managed based on the valve closing timing, it is possible to prevent the actual flow rate of EGR gas from decreasing due to contact with the removing member 40 .

Also, the plate-like member 30 constituting the removing member 40 and the rotating mechanism 50 contacts the valve 20 at the first bent portion 34 and the second bent portion 36 as the valve 20 moves in the closing direction. At this time, since the bent portions 34 and 36 are flexibly bent by receiving the force from the valve 20, the movement of the valve 20 in the closing direction is not hindered.

Also, the first bent portion 34 forming the removing member 40 bends in the direction opposite to the second bent portion 36 forming the second leaf spring, thereby the first bent portion 34 abuts at an acute angle with respect to the direction of rotation of the valve 20, so deposits can be effectively removed.

In addition, since the rotation direction of the valve 20 is restricted to one direction by the ratchet mechanism, it is possible to prevent the valve 20 from rotating forward or backward due to the urging force received from the plate member 30. can. As a result, deposits adhering to the entire circumference of the valve 20 can be efficiently removed.

In addition, since the first leaf spring that constitutes the removal member 40 and the second leaf spring that rotates the valve 20 are composed of one plate-shaped member 30, the number of members and the cost are not increased. The structure can be simplified by suppressing it.

The removing member 40 may have a structure in which an abutting member made of an elastic material such as rubber is attached to the tip portion 40a. In such a case, the abutting member improves the deposit removing effect. can do.

It should be noted that the ratchet mechanism is optional and valve structure 10 may be structured without the second leaf spring forming ratchet teeth 52 and ratchet pawl 54 . In this case, the valve 20 rotates in the bending direction of the first bending portion 34 (that is, the direction opposite to the R direction in FIG. 6) by the biasing force received from the removing member 40, which is the first leaf spring.

Further, as the rotating mechanism for rotating the valve 20, a motor for rotating the valve 20 may be used instead of the second plate spring. A motor may be incorporated within the housing 12 .

Next, another embodiment of the removing member 40 will be described with reference to FIG. In the embodiment shown in FIG. 9, the same reference numerals are given to the same configurations as in the above-described embodiment. In the embodiment shown in FIG. 9, the removal member 40 is attached to the plate-like member 30 formed of a flat plate material having no bent portion, and to the base end portion of the plate-like member 30 . and a biasing member 46 that applies a biasing force to the . The plate member 30 extends along the axial direction of the valve stem 20 and is installed so that the plate surface is inclined with respect to the axial direction. In the example shown in FIG. 9, the upper end side of the plate-like member 30 (the side to which the biasing member 46 is attached) is the front side of the paper, and the lower end side of the plate-like member 30 (the side in contact with the valve disc 20) is the back side of the paper. It is slanted so that it is on the side. The distal end portion of the plate member 30 , that is, the distal end portion 40 a of the removing member 40 is formed in a shape that conforms to the surface shape of the valve disc 20 . The biasing member 46 may be, for example, a coil spring having one end fixed to the housing 12 , and is arranged so as to bias the plate-like member 30 toward the distal end side of the valve stem 20 in the axial direction. 12 is attached.

In the embodiment shown in FIG. 9, the leaf spring 56 on which the tip ratchet pawl 54 is formed is formed separately from the plate-like member 30 that constitutes the removing member 40 . The plate spring 56 has a bent portion that is elastically bent at a region on the tip side that engages with the ratchet teeth 52 , and the valve 20 rotates due to the biasing force received from the plate spring 56 .

In this embodiment, while the valve 20 is moving from the valve closed position to the valve open position, the ratchet pawl 54 formed at the tip of the leaf spring 56 engages with the ratchet teeth 52 to move the valve 20 to the position indicated by the arrow. A biasing force is applied to rotate in the R direction. The plate-like member 30 that constitutes the removing member 40 has a distal end portion 40a separated from the valve disc 24 when the valve 20 is in the open position, and the valve 30 is opened as the valve 20 moves in the closing direction. contact the disk 24; By rotating the valve 20 while the tip portion 40a is in contact with the valve disc 24, the deposit adhering to the valve disc 24 is scraped off and removed by the tip portion 40a. The plate member 30 is elastically supported by the biasing member 46, and the biasing member 46 contracts as the valve 20 moves in the closing direction. do not have.

In addition, in the embodiment shown in FIG. 9, the ratchet mechanism is an option, and a structure without it is also possible. In this case, the valve 20 receives the biasing force of the biasing member 46 and rotates in the direction opposite to the R direction.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

For example, in the above-described embodiment, the valve structure 10 is applied to the EGR valve 20 installed in the EGR passage 8, but the scope of application is not limited to this, and can be applied to valves in general to which foreign matter such as soot adheres to the surface. It is possible to

Further, for example, the number of removing members 40 is not limited to one, and a plurality of removing members 40 may be installed at intervals in the circumferential direction of the valve disc 24 .

Reference Signs List 1 engine 4 intake passage 6 exhaust passage 8 EGR passage 10 valve structure 12 housing 13 passage 20 EGR valve 30 plate member 32 holding portion 34 first bent portion 36 second bent portion 40 removing member 50 rotating mechanism 52 ratchet teeth 54 ratchet pawl

Claims (5)

a valve that opens and closes a passage through which gas flows by means of a valve disk provided at the tip of the valve stem;
a removing member that is attached to the housing that forms the passage, contacts the valve disc as the valve moves in the closing direction, and removes deposits adhering to the surface of the valve disc. ,
The removal member is formed in a plate shape extending along the valve stem, and a tip portion that contacts the valve disc has a shape that conforms to the surface shape of the valve disc,
A valve structure, wherein the valve is rotated by a rotating mechanism that rotates the valve about the valve stem while the tip portion of the removing member is in contact with the valve. a plate-like member attached to the housing and having a distal end contacting the valve to impart a rotational force to the valve;
2. The valve structure according to claim 1, wherein said removing member is composed of said plate-like member. The rotating mechanism is
a plurality of ratchet teeth provided along the entire circumference of the valve so as to surround the valve stem;
3. A valve structure according to claim 1 or 2, comprising a ratchet pawl attached to said housing and engaging said ratchet teeth. The removal member is composed of a first leaf spring elastically bent at a region on the tip side,
The ratchet pawl is formed at the distal end of a second leaf spring that extends along the valve stem and has a distal end side region that is elastically bent,
4. The valve structure according to claim 3, wherein the first leaf spring and the second leaf spring are bent in opposite directions at the tip side regions thereof. 5. The valve structure according to claim 4, wherein said first leaf spring and said second leaf spring are integrally formed.

Images