Valve unit

Abstract

To effectively remove deposits accumulated on a seating surface of a valve.SOLUTION: A valve unit comprises: a valve capable of translationally moving between a fully closed position and a fully open position, and having a first shaft part; a first biasing member that biases the valve in a first direction to close the valve; a second shaft part that is connectable to the first shaft part; and a lock mechanism that changes between a connected and held state in which the first shaft part and the second shaft part are connected and held in a state in which they can move together, and a released state in which the connection between the first shaft part and the second shaft part is released.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a valve unit.

Background Art

[0002] Patent Document 1 discloses that in an internal combustion engine, when a mixture of air and fuel passes through an intake valve, fuel adheres to the seating surface of the intake valve, and the deposited fuel carbonizes, causing deposits to accumulate on the seating surface of the intake valve.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Thus, when deposits accumulate between the valve seat and the seating surface of the valve, there is a risk of a decrease in the flow rate of the gas flowing between the valve seat and the seating surface, and malfunction of the valve.

[0005] Therefore, an object of the present invention is to provide a valve unit capable of effectively removing deposits deposited on the seating surface of the valve.

Means for Solving the Problems

[0006] To solve the above problems, a valve unit according to an embodiment of the present invention includes a valve that is translatable between a fully closed position and a fully open position and has a first shaft portion, a first biasing member that biases the valve in a first direction to close the valve, a second shaft portion that can be connected to the first shaft portion, A locking mechanism whose state changes between a connection holding state in which the first shaft portion and the second shaft portion are connected and held in a state where they can move integrally, and a release state in which the connection between the first shaft portion and the second shaft portion is released. comprises.

Advantages of the Invention

[0007] According to the present invention, deposits deposited on the seating surface of the valve can be effectively removed.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0009] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. The dimensions, materials, and other specific numerical values shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In addition, in this specification and the drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to omit redundant description, and elements not directly related to the present invention are not shown.

[0010] FIG. 1 is a schematic diagram of an engine system 10 according to this embodiment. The engine system 10 is mounted on, for example, a vehicle 1. As shown in FIG. 1, the engine system 10 includes an engine 100, an intake pipe 200, an exhaust pipe 300, and an EGR device 400.

[0011] The intake pipe 200 and the exhaust pipe 300 are connected to the engine 100. The EGR device 400 is connected to the exhaust pipe 300 and the intake pipe 200, and communicates the inside of the exhaust pipe 300 and the inside of the intake pipe 200 through a bypass path that does not pass through the engine 100. Thereby, the EGR device 400 can return a part of the exhaust gas flowing through the exhaust pipe 300 to the intake pipe 200 as EGR gas.

[0012] The engine 100 is, for example, a horizontally opposed four-cylinder engine. However, it is not limited thereto, and the engine 100 may be an in-line engine, a V-type engine, or the like. A combustion chamber 110 is formed in the engine 100 by a cylinder bore, a cylinder head, and the crown surface of a piston.

[0013] An intake port 120 and an exhaust port 130 are formed in the cylinder head of the engine 100. The intake port 120 and the exhaust port 130 communicate with the combustion chamber 110. The tip of an intake valve 140 is located between the intake port 120 and the combustion chamber 110. The tip of an exhaust valve 150 is located between the exhaust port 130 and the combustion chamber 110.

[0014] In the cam chamber of the engine 100, a cam for the intake valve is provided, and the intake valve 140 is axially moved by the cam for the intake valve. Thereby, the space between the intake port 120 and the combustion chamber 110 is opened and closed.

[0015] Also, in the cam chamber of the engine 100, a cam for the exhaust valve is provided, and the exhaust valve 150 is axially moved by the cam for the exhaust valve. Thereby, the space between the exhaust port 130 and the combustion chamber 110 is opened and closed.

[0016] An intake passage 210 is formed inside the intake pipe 200. The intake passage 210 communicates the external space with the intake port 120. The intake passage 210 guides the air in the external space to the combustion chamber 110 through the intake port 120. Hereinafter, the air flowing through the intake passage 210 is also referred to as intake air. The intake pipe 200 includes an intake manifold 220, a throttle valve 230, and an air cleaner 240.

[0017] The intake manifold 220 distributes the intake air to each intake port 120 of the engine 100. The throttle valve 230 is configured to be able to adjust the amount of intake air introduced into the combustion chamber 110 of the engine 100. The throttle valve 230 is disposed between the intake manifold 220 and the air cleaner 240. The throttle valve 230 is configured to be able to open and close the intake passage 210. The throttle valve 230 is driven by an actuator according to the operation amount of an accelerator pedal (not shown). According to the operation amount of the accelerator pedal, the opening degree of the throttle valve 230 is adjusted. Thereby, the amount of intake air introduced into the engine 100 can be adjusted.

[0018] The air cleaner 240 is disposed on the upstream side of the intake air with respect to the throttle valve 230. The air cleaner 240 removes foreign matters flowing from the external space into the intake passage 210. For example, the air cleaner 240 removes foreign matters contained in the air flowing into the intake passage 210. The air from which the foreign matters have been removed by the air cleaner 240 flows through the intake passage 210 and is guided to the combustion chamber 110 of the engine 100.

[0019] The engine 100 is provided with an injector (not shown) and a spark plug (not shown). The injector injects fuel to supply fuel into the combustion chamber 110. The spark plug has its tip disposed in the combustion chamber 110 and ignites the air-fuel mixture supplied into the combustion chamber 110.

[0020] The air-fuel mixture is ignited by the spark plug at a predetermined timing and burned. By such combustion, the piston of the engine 100 reciprocates, and the reciprocating motion is converted into the rotational motion of the crankshaft.

[0021] An exhaust passage 310 is formed inside the exhaust pipe 300. The exhaust passage 310 communicates the exhaust port 130 with the external space. The exhaust gas after combustion generated in the combustion chamber 110 is discharged to the external space through the exhaust port 130 and the exhaust passage 310. The exhaust pipe 300 includes an exhaust manifold 320 and a catalyst 330.

[0022] The exhaust manifold 320 merges the exhaust gases discharged from the plurality of exhaust ports 130. The catalyst 330 is disposed on the downstream side of the exhaust relative to the exhaust manifold 320. The catalyst 330 is, for example, a three-way catalyst and contains platinum (Pt), palladium (Pd), and rhodium (Rh). The catalyst 330 removes hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) in the exhaust gas discharged from the combustion chamber 110.

[0023] The EGR device 400 is provided to reflux a part of the exhaust gas from the exhaust pipe 300 to the intake pipe 200 as EGR gas. The EGR device 400 includes an EGR pipe 410, an EGR cooler 420, and a valve unit 500.

[0024] One end of the EGR pipe 410 is connected to the exhaust pipe 300, and the other end of the EGR pipe 410 is connected to the intake pipe 200. Specifically, one end of the EGR pipe 410 of the present embodiment is connected to the downstream side of the catalyst 330 in the exhaust pipe 300, and the other end of the EGR pipe 410 is connected between the throttle valve 230 and the intake manifold 220 in the intake pipe 200.

[0025] By connecting the EGR pipe 410 to the downstream side of the catalyst 330 in the exhaust pipe 300, the exhaust gas from which hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) have been removed by the catalyst 330 can be introduced as EGR gas. Therefore, when the EGR gas flows through the EGR pipe 410, it is difficult for deposits to be formed in the EGR pipe 410. Note that the pressure of the exhaust gas flowing through the exhaust pipe 300 decreases after the exhaust gas passes through the catalyst 330. That is, the pressure of the exhaust gas flowing through the downstream side of the catalyst 330 in the exhaust pipe 300 is lower than the pressure of the exhaust gas flowing through the upstream side of the catalyst 330 in the exhaust pipe 300. In the EGR pipe 410 of the present embodiment, a part of the exhaust gas after passing through the catalyst 330 and having its pressure reduced is introduced as EGR gas. However, it is not limited to this, and the EGR pipe 410 may be connected to the upstream side of the catalyst 330 in the exhaust pipe 300. Specifically, the EGR pipe 410 may be connected between the exhaust manifold 320 and the catalyst 330 in the exhaust pipe 300.

[0026] An EGR flow path 430 is formed inside the EGR pipe 410, and the EGR flow path 430 communicates the exhaust flow path 310 and the intake flow path 210. The EGR flow path 430 refluxes a part of the EGR gas, which is a part of the exhaust gas generated in the combustion chamber 110, from the exhaust flow path 310 to the intake flow path 210. The EGR gas refluxed to the intake flow path 210 is mixed with the air flowing through the intake flow path 210 and introduced into the combustion chamber 110 of the engine 100. By mixing the air and the EGR gas, the combustion temperature in the combustion chamber 110 can be lowered.

[0027] In this way, by reducing the combustion temperature in the combustion chamber 110 with the EGR gas, the generation of NOx can be suppressed, and the exhaust gas can be improved. Further, by reducing the combustion temperature in the combustion chamber 110 with the EGR gas, the loss due to the cooling of the engine 100 can be reduced, and since the throttle opening increases, the pumping loss can also be suppressed. As a result, the fuel efficiency can be improved.

[0028] The EGR cooler 420 is provided in the EGR pipe 410 and cools the EGR gas flowing through the EGR passage 430. However, the EGR cooler 420 is not an essential component, and the EGR cooler 420 may not be provided in the EGR pipe 410. The valve unit 500 is provided in the EGR pipe 410 and opens and closes the EGR passage 430.

[0029] The control device 600 is electrically connected to the valve unit 500 and controls the driving of the valve unit 500.

[0030] The control device 600 includes one or more processors 600a and one or more memories 600b. The processor 600a includes, for example, a CPU (Central Processing Unit). The memory 600b includes, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The ROM is a storage element that stores programs and arithmetic parameters used by the CPU. The RAM is a storage element that temporarily stores data such as variables and parameters used in the processes executed by the CPU.

[0031] FIG. 2 is a block diagram showing an example of the functional configuration of the control device 600 according to the present embodiment. For example, as shown in FIG. 2, the control device 600 includes a drive control unit 610.

[0032] The processor 600a cooperates with the program included in the memory 600b and executes the program included in the memory 600b to realize various processes including the processes described below performed by the drive control unit 610.

[0033] The drive control unit 610 controls the drive of the valve unit 500. Specifically, as will be described in detail later, it controls the EGR valve 510 (see FIG. 3) included in the valve unit 500 to move between the fully closed position and the fully open position. Hereinafter, the detailed structure of the valve unit 500 according to the present embodiment will be described.

[0034] FIG. 3 is a schematic cross-sectional view showing the configuration of the valve unit 500 according to the present embodiment. As shown in FIG. 3, the valve unit 500 includes an EGR valve 510, a connection member 520, an actuator 530, and a locking mechanism 540.

[0035] The EGR valve 510 has a first shaft portion 512 and a valve body 514. Note that FIG. 3 shows the configuration of the valve unit 500 when the EGR valve 510 is in the fully closed position. The first shaft portion 512 penetrates the wall portion of the EGR pipe 410. One end 512a of the first shaft portion 512 is disposed inside the EGR pipe 410, and the other end 512b of the first shaft portion 512 is disposed outside the EGR pipe 410.

[0036] Also, outside the EGR pipe 410, a first regulating member 512c and a second regulating member 512d are provided on the outer peripheral surface of the first shaft portion 512. The first regulating member 512c and the second regulating member 512d are provided between one end 512a and the other end 512b of the first shaft portion 512, and the first regulating member 512c is disposed closer to the other end 512b side than the second regulating member 512d. The first regulating member 512c and the second regulating member 512d are, for example, disk-shaped. The outer diameters of the first regulating member 512c and the second regulating member 512d are larger than the outer diameter of the first shaft portion 512. Also, the outer diameters of the first regulating member 512c and the second regulating member 512d are larger than the inner diameter of the hole in the EGR pipe 410 through which the first shaft portion 512 is inserted.

[0037] The valve body 514 is connected to one end 512a of the first shaft portion 512. The valve body 514 has a seating surface 514a that can contact a valve seat 410a formed on the inner wall of the EGR pipe 410. When the seating surface 514a of the valve body 514 contacts the valve seat 410a, the EGR passage 430 is blocked by the valve body 514 and enters a closed state. Further, when the seating surface 514a of the valve body 514 is separated from the valve seat 410a, the EGR passage 430 is opened from the valve body 514 and enters an open state.

[0038] As shown in FIG. 3, the EGR passage 430 includes an intake-side EGR passage 430a that is on the intake passage 210 side of the valve seat 410a and communicates with the intake passage 210, and an exhaust-side EGR passage 430b that is on the exhaust passage 310 side of the valve seat 410a and communicates with the exhaust passage 310. Here, a state in which the valve body 514 contacts the valve seat 410a and the communication between the intake-side EGR passage 430a and the exhaust-side EGR passage 430b is blocked is referred to as a closed state of the EGR passage 430. Further, a state in which the valve body 514 is separated from the valve seat 410a and the intake-side EGR passage 430a and the exhaust-side EGR passage 430b communicate with each other is referred to as an open state of the EGR passage 430. Further, hereinafter, a position at which the valve body 514 of the EGR valve 510 contacts the valve seat 410a is referred to as a fully closed position of the EGR valve 510.

[0039] The connecting member 520 has a main body 522 and a spring 524. The main body 522 connects the outer surface of the EGR pipe 410 and the actuator 530. The main body 522 has a through hole 522a, a first recessed portion 522b, and a second recessed portion 522c. The main body 522 has a substantially cylindrical shape. The first recessed portion 522b is recessed from the lower end surface to the upper end surface of the main body 522. The second recessed portion 522c is recessed from the upper end surface to the lower end surface of the main body 522. The first recessed portion 522b and the second recessed portion 522c are, for example, cylindrical recesses. The inner diameter of the first recessed portion 522b is smaller than the inner diameter of the second recessed portion 522c. However, the present invention is not limited thereto, and the inner diameter of the first recessed portion 522b may be equal to or larger than the inner diameter of the second recessed portion 522c. The first recessed portion 522b and the second recessed portion 522c are communicated with each other by the through hole 522a. The first shaft portion 512 of the EGR valve 510 is inserted into the through hole 522a. The through hole 522a is formed between the first recessed portion 522b and the second recessed portion 522c.

[0040] A circular opening of the first recessed portion 522b is formed on the lower end surface of the main body 522. When the lower end surface of the main body 522 is connected to the outer surface of the EGR pipe 410, the circular opening of the first recessed portion 522b is closed by the outer surface of the EGR pipe 410. A spring 524 as a first biasing member is disposed inside the first recessed portion 522b. Further, a first restricting member 512c and a second restricting member 512d of the first shaft portion 512 are disposed inside the first recessed portion 522b. The inner diameter of the first recessed portion 522b is larger than the outer diameters of the first restricting member 512c and the second restricting member 512d. The first recessed portion 522b functions as a housing portion for housing the spring 524, the first restricting member 512c, and the second restricting member 512d. Further, the actuator 530 is fitted into the second recessed portion 522c. The second recessed portion 522c functions as a housing portion for housing a part of the actuator 530. In this way, the lower end surface of the main body 522 of the connecting member 520 is connected to the EGR pipe 410, and the second recessed portion 522c is closed by the actuator 530. Therefore, the EGR gas flowing through the EGR passage 430 is less likely to leak from the connection portion between the lower end surface of the main body 522 and the EGR pipe 410, and the connection portion between the second recessed portion 522c and the actuator 530.

[0041] One end of the spring 524 abuts against the outer surface of the EGR pipe 410, and the other end of the spring 524 abuts against the first regulating member 512c. Thereby, the spring 524 biases the first regulating member 512c in a direction away from the outer surface of the EGR pipe 410. The first regulating member 512c is connected to the first shaft portion 512, and the first shaft portion 512 is connected to the valve body 514. Therefore, the EGR valve 510 including the first regulating member 512c, the first shaft portion 512, and the valve body 514 is biased by the biasing force of the spring 524. In the present embodiment, the spring 524 biases the EGR valve 510 in a first direction R1 in which the EGR valve 510 closes toward the fully closed position. The first direction R1 is the upward direction in FIG. 3. The first regulating member 512c restricts the movement of the other end of the spring 524.

[0042] The first regulating member 512c is configured not to abut against the bottom surface of the first recessed portion 522b within the first recessed portion 522b. The first regulating member 512c is disposed at a position separated from the bottom surface of the first recessed portion 522b in the fully closed position of the EGR valve 510. That is, the first regulating member 512c is non-contact with the bottom surface of the first recessed portion 522b in the fully closed position of the EGR valve 510. Further, the second regulating member 512d is configured to be able to abut against the outer surface of the EGR pipe 410 within the first recessed portion 522b.

[0043] When the EGR valve 510 moves in the first direction R1 by the biasing force of the spring 524 and the seating surface 514a of the valve body 514 abuts against the valve seat 410a, the position of the EGR valve 510 becomes the fully closed position. On the contrary, when the EGR valve 510 moves in a second direction R2 opposite to the first direction R1 against the biasing force of the spring 524 and the second regulating member 512d abuts against the outer surface of the EGR pipe 410, the position of the EGR valve 510 becomes the fully open position. The second direction R2 is the downward direction in FIG. 3. The EGR valve 510 is configured to be translatable between the fully closed position and the fully open position.

[0044] The actuator 530 has a main body 532 and a second shaft portion 534. The main body 532 houses the second shaft portion 534. The second shaft portion 534 is configured to be connectable to the first shaft portion 512. In the present embodiment, the second shaft portion 534 is not coaxial with the first shaft portion 512. The axes of the first shaft portion 512 and the second shaft portion 534 are parallel to each other. However, the present invention is not limited to this, and the second shaft portion 534 may be coaxial with the first shaft portion 512.

[0045] The state of the locking mechanism 540 changes between a connection holding state in which the first shaft portion 512 and the second shaft portion 534 are connected and held in a state where they can move integrally, and a release state in which the connection between the first shaft portion 512 and the second shaft portion 534 is released.

[0046] FIG. 4 is a schematic cross-sectional view showing the configuration of the locking mechanism 540 according to the present embodiment. In FIG. 4, in order to explain the configuration of the locking mechanism 540 in an easy-to-understand manner, the gap between the engaging portion 544 and the engaged portion 542 is shown larger than the actual size. As shown in FIG. 4, the locking mechanism 540 includes an engaged portion 542, an engaging portion 544, and a spring 546. The spring 546 in the present embodiment is a compression coil spring as a second biasing member that biases the engaging portion 544 toward the engaged portion 542.

[0047] The engaged portion 542 is provided at the end portion on the other end 512b side of the first shaft portion 512. In the present embodiment, the engaged portion 542 is a hemispherical recess formed in the first shaft portion 512. The engaging portion 544 and the spring 546 are provided at the end portion on the one end 534a side of the second shaft portion 534. In the present embodiment, a cylindrical recess 534b is formed in the one end 534a of the second shaft portion 534. The recess 534b is recessed radially from the outer surface of the second shaft portion 534. The engaging portion 544 and the spring 546 are disposed in the recess 534b of the second shaft portion 534. In the example shown in FIG. 4, in the radial direction of the first shaft portion 512 and the second shaft portion 534, the recess 534b faces the engaged portion 542.

[0048] The engaging portion 544 is a spherical ball and is configured to be engageable with the engaged portion 542. The spring 546 biases the engaging portion 544 toward the engaged portion 542. The engaging portion 544 is configured to be movable in the central axis direction of the recessed portion 534b by the biasing force of the spring 546. The central axis direction of the recessed portion 534b is a direction orthogonal to the central axis of the second shaft portion 534. The recessed portion 534b guides the engaging portion 544 in its central axis direction. FIG. 4 shows a state in which the engaging portion 544 and the engaged portion 542 are engaged.

[0049] In this embodiment, an example will be described in which the engaged portion 542 is provided on the first shaft portion 512, and the recessed portion 534b, the engaging portion 544, and the spring 546 are provided on the second shaft portion 534. However, the present invention is not limited to this. For example, the engaged portion 542 may be provided on the second shaft portion 534, and the recessed portion 534b, the engaging portion 544, and the spring 546 may be provided on the first shaft portion 512.

[0050] That is, the engaged portion 542 may be provided on one of the first shaft portion 512 and the second shaft portion 534, and the engaging portion 544 and the spring 546 may be configured to be provided on the other of the first shaft portion 512 and the second shaft portion 534.

[0051] In a state where the engaged portion 542 and the engaging portion 544 are engaged, the spring 546 biases the engaging portion 544 toward the engaged portion 542, so that the first shaft portion 512 and the second shaft portion 534 are connected and maintained in a state where they can move integrally, which is a connection holding state. On the other hand, in a state where the engaged portion 542 and the engaging portion 544 are not engaged, the connection between the first shaft portion 512 and the second shaft portion 534 is released, which is a release state.

[0052] FIG. 5 is a schematic cross-sectional view showing the configuration of the valve unit 500 when the EGR valve 510 according to this embodiment is in the fully open position. As shown in FIGS. 3 and 5, when moving the EGR valve 510 from the fully closed position to the fully open position, the actuator 530 drives the second shaft portion 534 in the second direction R2, which is downward in FIG. 5, in the central axis direction of the second shaft portion 534.

[0053] The locking mechanism 540 integrally moves the first shaft portion 512 and the second shaft portion 534 in the second direction R2 while maintaining the connection holding state. When the first shaft portion 512 moves in the second direction R2, the second restricting member 512d abuts against the outer surface of the EGR pipe 410, and the EGR valve 510 reaches the fully open position. In a state where the second restricting member 512d is in contact with the outer surface of the EGR pipe 410, the second restricting member 512d restricts the movement of the EGR valve 510 in the second direction R2. Therefore, the EGR valve 510 does not open beyond the fully open position.

[0054] In the state shown in FIG. 5, when the EGR gas passes between the seating surface 514a of the EGR valve 510 and the valve seat 410a, deposits may adhere to the seating surface 514a and the valve seat 410a, and deposits may accumulate between the seating surface 514a and the valve seat 410a. When deposits accumulate between the seating surface 514a and the valve seat 410a, there is a risk of a decrease in the flow rate of the gas flowing between the seating surface 514a and the valve seat 410a and a malfunction of the valve unit 500.

[0055] Therefore, in the present embodiment, at the fully open position of the EGR valve 510, the locking mechanism 540 is changed from the connection holding state to the released state. As a result, the first shaft portion 512 of the EGR valve 510 moves from the fully open position to the fully closed position by the biasing force of the spring 524, and the seating surface 514a and the valve seat 410a can be collided with each other. By the energy of this collision, the deposits accumulated between the seating surface 514a and the valve seat 410a can be removed.

[0056] The drive control unit 610 executes a deposit removal process, for example, when turning off the ignition of the vehicle 1. The deposit removal process is a process of moving the EGR valve 510 to the fully open position, changing the locking mechanism 540 from the connection holding state to the released state in a state where the position of the EGR valve 510 is at the fully open position, and removing the accumulated deposits.

[0057] FIG. 6 is a schematic cross-sectional view of a valve unit 500 showing a released state of a lock mechanism 540 according to the present embodiment. As shown in FIGS. 5 and 6, at the fully open position of the EGR valve 510, the actuator 530 further drives the second shaft portion 534 in the central axis direction of the second shaft portion 534 in the downward second direction R2 in FIG. 6.

[0058] FIG. 7 is a schematic enlarged cross-sectional view showing the configuration of the lock mechanism 540 shown in FIG. 6. When the second shaft portion 534 is driven in the second direction R2 as shown in FIG. 6 from the connection holding state of the lock mechanism 540 shown in FIG. 4, the first shaft portion 512 and the second shaft portion 534 move relatively in the central axis direction as shown in FIG. 7. Along with the relative movement of the first shaft portion 512 and the second shaft portion 534, the engaging portion 544 moves along the hemispherical inner peripheral surface of the engaged portion 542 and is pushed out to the outer peripheral surface side of the first shaft portion 512. At this time, the spring 546 is compressed by the pushed-out engaging portion 544. Thus, when the engaging portion 544 is detached from the hemispherical inner peripheral surface of the engaged portion 542, the engagement between the engaged portion 542 and the engaging portion 544 is released. When the engagement between the engaged portion 542 and the engaging portion 544 is released, the connection between the first shaft portion 512 and the second shaft portion 534 is released. Further, the engaging portion 544 is pressed against the outer peripheral surface of the first shaft portion 512 by the biasing force of the spring 546 and slides on the outer peripheral surface of the first shaft portion 512 in a state of being in contact with the first shaft portion 512.

[0059] FIG. 8 is a schematic cross-sectional view of the valve unit 500 showing a state where the seating surface 514a of the EGR valve 510 collides with the valve seat 410a by the biasing force of the spring 524 according to the present embodiment. As shown in FIG. 8, since the connection between the first shaft portion 512 and the second shaft portion 534 is released when the lock mechanism 540 is in the released state, the first shaft portion 512 can move in the central axis direction regardless of the movement of the second shaft portion 534.

[0060] And since the spring 524 biases the first regulating member 512c in a direction separating it from the outer surface of the EGR pipe 410, the first regulating member 512c moves in the first direction R1 separating it from the outer surface of the EGR pipe 410.

[0061] As the first regulating member 512c moves, the EGR valve 510 moves in the first direction R1 from the fully open position toward the fully closed position, and the seating surface 514a and the valve seat 410a collide at the fully closed position. Due to the energy of this collision, deposits accumulated between the seating surface 514a and the valve seat 410a are removed.

[0062] In a state where the seating surface 514a and the valve seat 410a are in contact, the fully closed position of the EGR valve 510 is maintained by the biasing force of the spring 524. Also at this time, the locking mechanism 540 is in the released state.

[0063] In a state where the EGR valve 510 is in the fully closed position shown in FIG. 8, the actuator 530 drives the second shaft portion 534 in the first direction R1, which is the upward direction in FIG. 8, in the central axis direction of the second shaft portion 534. At this time, since the connection between the first shaft portion 512 and the second shaft portion 534 is released, only the second shaft portion 534 moves in the first direction R1 without the first shaft portion 512 moving in the central axis direction.

[0064] As the second shaft portion 534 moves in the first direction R1, the engaging portion 544 of the locking mechanism 540 moves in the first direction R1 together with the second shaft portion 534 while sliding on the outer peripheral surface of the first shaft portion 512. When the second shaft portion 534 moves in the first direction R1, as shown in FIGS. 3 and 4, the engaging portion 544 reaches a position where it engages with the engaged portion 542 of the first shaft portion 512, and due to the biasing force of the spring 546, the engaged portion 542 and the engaging portion 544 engage again. When the engaged portion 542 and the engaging portion 544 engage, the locking mechanism 540 changes from the released state to the connection holding state.

[0065] Thus, the valve unit 500 of the present embodiment has a locking mechanism 540 whose state changes between the above-described connection holding state and the release state. Thereby, while the deposit removal process is not executed, by setting the locking mechanism 540 to the connection holding state, the EGR valve 510 can be moved between the fully closed position and the fully open position. Further, when the deposit removal process is executed, by setting the locking mechanism 540 to the release state, the seating surface 514a and the valve seat 410a collide due to the biasing force of the spring 524, and the deposited deposit can be removed.

[0066] Further, the locking mechanism 540 of the present embodiment includes an engaged portion 542, an engaging portion 544, and a spring 546. In the connection holding state, the engaging portion 544 engages with the engaged portion 542 in a state biased by the spring 546. Thereby, the locking mechanism 540 can be changed between the connection holding state and the release state only by driving the second shaft portion 534. For example, compared with the case where the locking mechanism 540 is driven by a hydraulic or electromagnetic drive device, it can be configured simply.

[0067] Further, the valve unit 500 of the present embodiment includes an actuator 530 as a drive mechanism that moves the second shaft portion 534 in the moving direction of the EGR valve 510. Thereby, without requiring a complicated mechanism, by simply moving the second shaft portion 534 in the moving direction of the EGR valve 510, the driving between the fully closed position and the fully open position of the EGR valve 510 and the transition of the locking mechanism 540 from the connection holding state to the release state can be performed.

[0068] In addition, the valve unit 500 of the present embodiment includes a second restricting member 512d that restricts the movement of the EGR valve 510 in the second direction R2 to further open the EGR valve 510 at the fully open position of the EGR valve 510. In the present embodiment, with the lock mechanism 540 in the connected and held state, the actuator 530 moves the second shaft portion 534 in the second direction R2 to move the EGR valve 510 to the fully open position. Then, thereafter, by further moving the second shaft portion 534 in the second direction R2, the state of the lock mechanism 540 is changed from the connected and held state to the released state. By having the second restricting member 512d, the second shaft portion 534 can be further moved in the second direction R2 while the EGR valve 510 is held at the fully open position. As a result, the lock mechanism 540 can be easily changed to the released state at the fully open position of the EGR valve 510.

[0069] Further, the valve unit 500 of the present embodiment releases the connection between the first shaft portion 512 and the second shaft portion 534 by changing the lock mechanism 540 from the connected and held state to the released state with the EGR valve 510 open. Then, the EGR valve 510 is moved in the first direction R1 by the biasing force of the spring 524 so that the seating surface 514a collides with the valve seat 410a. In the released state of the lock mechanism 540, by moving the EGR valve 510 in the first direction R1 by the biasing force of the spring 524, the seating surface 514a and the valve seat 410a can be made to collide without requiring an additional configuration.

[0070] FIG. 9 is a schematic cross-sectional view showing a lock mechanism 1540 according to a modified example. In FIG. 9, in order to explain the configuration of the lock mechanism 1540 more clearly, the gap between the engaging portion 1544 and the engaged portion 542 is shown larger than the actual size. For components that are substantially the same as those of the valve unit 500 in the above-described embodiment, the same reference numerals are given and the description thereof is omitted. In the lock mechanism 1540 of the modified example, an engaging portion 1544 and a spring 1546 are provided in place of the engaging portion 544 and the spring 546 in the above-described embodiment. Further, the lock mechanism 1540 of the modified example includes a hydraulic pump 1550 and an oil passage 1560, which is different from the above-described embodiment. Hereinafter, the details of the lock mechanism 1540 in the modified example will be described.

[0071] As shown in FIG. 9, the lock mechanism 1540 of the modified example includes an engaged portion 542, an engaging portion 1544, a spring 1546, a hydraulic pump 1550, and an oil passage 1560. The configuration of the engaged portion 542 is as described in the above-described embodiment. In the example shown in FIG. 9, the left side of the engaging portion 1544 has a hemispherical shape, and the right side of the engaging portion 1544 has a cylindrical shape. That is, the engaging portion 1544 of the modified example has a shape in which a hemispherical shape and a cylindrical shape are combined. The left side of the engaging portion 1544 is configured to be engageable with the engaged portion 542. Further, the outer diameter of the cylindrical shape of the engaging portion 1544 is substantially equal to the inner diameter of the recessed portion 534b. That is, the gap between the recessed portion 534b and the engaging portion 544 is set to be as small as possible so that the oil flowing through the oil passage 1560 is difficult to leak. Further, the spring 1546 of the modified example biases the engaging portion 1544 in a direction away from the engaged portion 542. That is, the spring 1546 is a tension coil spring that pulls the engaging portion 1544.

[0072] The hydraulic pump 1550 supplies oil to the oil passage 1560. The oil passage 1560 is formed to extend in the axial direction of the second shaft portion 534. One end of the oil passage 1560 is connected to the hydraulic pump 1550, and the other end of the oil passage 1560 is connected to the recessed portion 534b. By applying a hydraulic pressure equal to or higher than a predetermined pressure to the oil passage 1560, the hydraulic pump 1550 can move the engaging portion 1544 toward the engaged portion 542 against the biasing force of the spring 1546. On the other hand, by applying a hydraulic pressure lower than the predetermined pressure to the oil passage 1560 by the hydraulic pump 1550, the engaging portion 1544 can be moved in a direction away from the engaged portion 542 by the biasing force of the spring 1546.

[0073] Further, when a hydraulic pressure equal to or higher than a predetermined pressure is applied by the hydraulic pump 1550 in a state where the engaged portion 542 and the engaging portion 544 are engaged, the lock mechanism 1540 enters a connection holding state in which the first shaft portion 512 and the second shaft portion 534 are connected and can move integrally.

[0074] On the other hand, when the hydraulic pressure in the oil passage 1560 is reduced to less than the predetermined pressure by the hydraulic pump 1550 and the engagement between the engaged portion 542 and the engaging portion 544 is released, the lock mechanism 1540 enters a release state in which the connection between the first shaft portion 512 and the second shaft portion 534 is released.

[0075] Also in this modification, the state of the lock mechanism 1540 is configured to be changeable between the above-described connection holding state and the release state. Therefore, similar to the above-described embodiment, in the contact holding state, the EGR valve 510 can be moved between the fully closed position and the fully open position, and in the release state, the deposit accumulated between the seating surface 514a and the valve seat 410a can be removed.

[0076] As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings. Needless to say, the present invention is not limited to such embodiments. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention.

[0077] In the above-described embodiments and modified examples, an example in which the second shaft portion 534 is applied to the drive shaft of the actuator 530 has been described. However, the present invention is not limited to this, and the second shaft portion 534 may be applied to a shaft other than the drive shaft of the actuator 530, such as a shaft connected to the drive shaft of the actuator 530 via another member.

[0078] In the above-described embodiments and modified examples, an example in which the valve unit 500 is applied to the EGR valve 510 has been described. However, the present invention is not limited to this, and the valve unit 500 may be a valve unit applied to a valve other than the EGR valve 510, such as an intake valve 140 or an exhaust valve 150.

Explanation of Reference Numerals

[0079] 10 Engine system 100 Engine 200 Intake pipe 300 Exhaust pipe 400 EGR device 410 EGR pipe 410a Valve seat 430 EGR flow path 500 Valve unit 510 EGR valve 512 First shaft portion 512c First restricting member 512d Second restricting member 514 Valve body 514a Seating surface 520 Connecting member 522 Body 524 Spring 530 Actuator 532 Body 534 Second shaft portion 540 Lock mechanism 542 Engaged portion 544 Engaging portion 546 Spring 600 Control device 610 Drive control unit 1540 Lock mechanism 1544 Engagement part 1546 Spring 1550 Hydraulic pump 1560 Oil passage

Claims

1. a valve that is translationally movable between a fully closed position and a fully open position and has a first stem; A first biasing member biases the valve in a first direction to close the valve; A second shaft portion connectable to the first shaft portion; a lock mechanism that changes between a connected and held state in which the first shaft portion and the second shaft portion are connected and held in a state in which they can move together, and a released state in which the connection between the first shaft portion and the second shaft portion is released; A valve unit comprising:

2. The locking mechanism includes: an engaged portion provided on one of the first shaft portion and the second shaft portion; an engaging portion provided on the other of the first shaft portion and the second shaft portion and capable of engaging with the engaged portion; a second biasing member provided on the other of the first shaft portion and the second shaft portion and biasing the engaging portion toward the engaged portion; Equipped with The valve unit according to claim 1 , wherein in the connected and held state, the engaging portion engages with the engaged portion while being biased by the second biasing member.

3. A drive mechanism that moves the second shaft portion in the valve movement direction. The valve unit according to claim 2 , comprising:

4. a restricting member that restricts movement of the valve in a second direction to open the valve at the fully open position; When the state of the locking mechanism is the connected and held state, the drive mechanism moves the second shaft portion in the second direction to move the valve to the fully open position, and then, by further moving the second shaft portion in the second direction, the state of the locking mechanism changes from the connected and held state to the released state. The valve unit according to claim 3.

5. When the state of the locking mechanism changes from the connected and held state to the released state while the valve is open, the connection between the first shaft portion and the second shaft portion is released, and the valve is moved in the first direction by the biasing force of the first biasing member. The valve unit according to any one of claims 1 to 4.

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