JP5774394B2 - Flow control valve - Google Patents

Description

  The present invention relates to a flow control valve that controls the flow rate of a fluid.

  For example, a PCV (Positive Crankcase Ventilation) valve is used as a flow control valve for controlling the flow rate of blow-by gas in a blow-by gas reduction device for an internal combustion engine (engine) in a vehicle such as an automobile (see, for example, Patent Document 1).

A conventional example of a PCV valve will be described. FIG. 11 is a cross-sectional view showing a PCV valve.
As shown in FIG. 11, the PCV valve 1 includes a case 2, a valve body 3, and a coil spring 4. The case 2 is provided with a gas passage 5 extending in the axial direction (left-right direction in FIG. 11). In the gas passage 5, blow-by gas from the upstream side (right side in FIG. 11) flows toward the downstream side (left side in FIG. 11). The valve body 3 is provided in the gas passage 5 so as to be able to advance and retract in the axial direction. A measuring hole 6 a is formed in the middle of the gas passage 5. In addition, a measuring surface 6b is formed on the outer peripheral surface of the front end portion (front end portion) 3a of the valve body 3. The measuring portion 6 is configured by the measuring hole 6a (specifically, the inner peripheral surface) and the measuring surface 6b.

  A guide flange 8 is formed at the rear end portion (the right end portion in FIG. 11) of the valve body 3 so as to project radially outward in a flange shape. The outer peripheral surface of the guide flange 8 is capable of sliding contact with a passage wall surface of the gas passage 5 (specifically, a passage wall surface upstream of the measuring unit 6) 5a. Further, a notch 8 a that allows the passage of blow-by gas is formed on the outer peripheral portion of the guide flange 8. The coil spring 4 is a cylindrical coil spring and is interposed between the guide flange 8 of the valve body 3 and a stepped surface 6c formed on the upstream end surface of the measuring hole 6a. The coil spring 4 urges the valve body 3 in the backward direction (rightward in FIG. 11).

  The PCV valve 1 controls, or measures, the flow rate of the blow-by gas flowing through the gas passage 5 by adjusting the passage cross-sectional area of the metering unit 6 by moving the valve body 3 back and forth. A cushion spring 9 is provided in the passage portion of the gas passage 5 on the downstream side of the measuring hole 6a. The cushion spring 9 is formed of a coil spring and elastically receives the valve body 3 during advance to the most advanced position.

JP-A-2005-240605

  According to the PCV valve 1, the rear end portion of the valve body 3 is supported by the sliding contact of the guide flange 8 with the passage wall surface 5 a of the gas passage 5. Is prevented. Further, the rear end portion (movable side end portion) of the coil spring 4 is locked to the guide flange 8 so that the rear end portion of the valve body 3 is elastically held by the coil spring 4. ing. However, the tip 3a of the valve body 3 is in a free state. For this reason, when an external force is applied to the PCV valve 1, there is a problem that the tip portion 3 a of the valve body 3 tends to swing in the radial direction. This is because the operation stability of the valve body 3 is lowered due to an increase in the radial swing width and the swing speed at the distal end portion 3a of the valve body 3, and the distal end portion 3a of the valve body 3 collides with the inner peripheral surface of the measuring hole 6a. Therefore, it is desired to take measures against the occurrence of the impact force and the hitting sound and the durability due to the wear of the measuring hole 6a and / or the measuring surface 6b.

  The problem to be solved by the present invention is to provide a flow rate control valve capable of preventing radial deflection of the tip of the valve body.

A first invention includes a case provided with a fluid passage, a valve body provided in the fluid passage so as to be movable back and forth in an axial direction, and a coil spring for biasing the valve body in a backward direction, and is provided in the middle of the fluid passage. A flow rate control that controls the flow rate of the fluid by adjusting the passage cross-sectional area of the measurement unit by moving the valve body in the axial direction by forming a measurement unit with the formed measurement hole and the measurement surface formed in the valve body It is a valve, Comprising: A coil spring is interposed between the front-end | tip part of a valve body, and the spring seat part arrange | positioned downstream from the front-end | tip part of the valve body in the fluid passage of a case. According to this configuration, since the tip end portion of the valve body is elastically held by the coil spring, the radial deflection of the tip end portion of the valve body can be prevented. As a result, the radial deflection width and deflection speed at the tip of the valve body are reduced, the operational stability of the valve body is improved, the impact force and sound is reduced by preventing the measurement surface from colliding with the measurement hole, the measurement hole and It is possible to improve durability by preventing wear on the measurement surface.

According to a second invention, in the first invention, a drum-shaped coil spring is used as the coil spring. According to this configuration, since the axial middle portion of the drum-shaped coil spring is reduced in diameter, the contact of the coil spring with the case is reduced, and changes in flow rate due to wear and frictional resistance due to the contact are prevented. can do.

According to a third invention, in the first invention, a conical coil spring is used as the coil spring. According to this configuration, since the diameter of the conical coil spring is reduced from one end side to the other end side, the contact of the coil spring with the case is reduced, and the flow rate due to the increase in wear and frictional resistance due to the contact is reduced. Changes can be prevented.

In a fourth invention according to any one of the first to third inventions, the valve body is formed with a plurality of guide ribs that are in sliding contact with the inner peripheral surface of the measuring hole and project radially. According to this structure, the center part of a valve body is supported by the sliding contact of each guide rib with respect to the internal peripheral surface of a measurement hole, and the radial shake of the center part of a valve body can be prevented.

According to a fifth invention, in any one of the first to fourth inventions, the valve body is formed with a flange-shaped guide flange that is in sliding contact with the passage wall surface upstream of the measuring portion in the fluid passage. Yes. According to this configuration, the back end portion of the valve body is supported by the sliding contact of the guide flange with the passage wall surface on the upstream side in the fluid passage, thereby preventing radial deflection of the rear end portion of the valve body. it can.

A sixth invention is a PCV valve used in the blow-by gas reduction device for an internal combustion engine in any one of the first to fifth inventions . According to this configuration, vibration in the radial direction of the tip of the valve body in the PCV valve can be prevented.

It is sectional drawing which shows the PCV valve | bulb concerning Embodiment 1. FIG. It is a front view which shows a PCV valve | bulb. It is a block diagram which shows a blow-by gas reduction apparatus. It is sectional drawing which shows the PCV valve | bulb concerning Embodiment 2. FIG. It is sectional drawing which shows the PCV valve | bulb concerning Embodiment 3. FIG. It is sectional drawing which shows the PCV valve | bulb concerning Embodiment 4. It is sectional drawing which shows the PCV valve | bulb concerning Embodiment 5. FIG. It is a front view which shows a PCV valve | bulb. It is sectional drawing which shows the PCV valve | bulb concerning Embodiment 6. FIG. It is a front view which shows a PCV valve | bulb. It is sectional drawing which shows the PCV valve | bulb concerning a prior art example.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[Embodiment 1]
The first embodiment will be described. In Embodiment 1, the PCV valve used for the blow-by gas reduction apparatus of an internal combustion engine is illustrated as a flow control valve. For convenience of explanation, the PCV valve will be explained after explaining an example of the blow-by gas reducing device. FIG. 3 is a block diagram showing the blow-by gas reduction device.
As shown in FIG. 3, the blow-by gas reduction device 10 introduces blow-by gas that has leaked into the crankcase 15 of the cylinder block 14 from the combustion chamber of the engine body 13 of the engine 12, which is an internal combustion engine, into the intake manifold 20. This is a system for burning again in the combustion chamber.

  The engine body 13 includes the cylinder block 14, an oil pan 16 fastened to the lower surface side of the crankcase 15, a cylinder head 17 fastened to the upper surface side of the cylinder block 14, and an upper surface side of the cylinder head 17. The cylinder head cover 18 is fastened. The engine body 13 obtains driving force through a process such as intake, compression, explosion, and exhaust. Further, blow-by gas is generated in the engine main body 13, that is, in the crankcase 15 and in the cylinder head cover 18 communicating with the crankcase 15 as combustion occurs in the combustion chamber (not shown) of the engine main body 13. . Further, the inside of the cylinder head cover 18 and the inside of the crankcase 15 into which blow-by gas flows corresponds to “inside of the engine body” in this specification.

  The cylinder head cover 18 is provided with a fresh air inlet 18a and a blow-by gas outlet 18b. One end (downstream end) of the fresh air introduction passage 30 communicates with the fresh air introduction port 18a. One end (upstream end) of the blowby gas passage 36 is communicated with the blowby gas outlet 18b. The fresh air inlet 18 a and / or the blow-by gas outlet 18 b can be provided in the crankcase 15 instead of the cylinder head cover 18.

  One end (downstream end) of the intake manifold 20 is communicated with the cylinder head 17. The intake manifold 20 includes a surge tank 21. An air cleaner 25 communicates with the other end (upstream end) of the intake manifold 20 via a throttle body 24 and an intake pipe 23. The throttle body 24 includes a throttle valve 24a. The throttle valve 24a is connected to, for example, an accelerator pedal (not shown), and is opened and closed according to the depression amount (operation amount) of the pedal. The air cleaner 25 introduces air so-called fresh air, and has a built-in filter element 26 for filtering the fresh air. The air cleaner 25, the intake pipe 23, the throttle body 24, and the intake manifold 20 form a series of intake passages 27 for introducing fresh air, that is, intake air into the combustion chamber of the engine body 13. In the intake passage 27, a passage portion upstream of the throttle valve 24a is referred to as an upstream intake passage portion 27a, and a passage portion downstream of the throttle valve 24a is referred to as a downstream intake passage portion 27b.

  A fresh air inlet 29 is formed in the intake pipe 23. The fresh air inlet 29 communicates with the other end (upstream end) of the fresh air introduction passage 30. The fresh air introduction passage 30 is provided with a backflow prevention valve 32. The backflow prevention valve 32 allows the flow of so-called fresh air (see arrow Y1 in FIG. 3) from the upstream intake passage portion 27a into the crankcase 15 and flows in the reverse direction, that is, backflow. (See arrow Y3 in FIG. 3). The surge tank 21 has a blow-by gas inlet 34 formed therein. The blow-by gas introduction port 34 communicates with the other end (downstream end) of the blow-by gas passage 36.

  Next, the operation of the blowby gas reduction device 10 will be described. When the engine 12 is light and medium load, the throttle valve 24a is almost fully closed. For this reason, a negative pressure (a negative pressure that increases toward the vacuum side) greater than that of the upstream intake passage portion 27a is generated in the intake passage portion 27b on the downstream side of the intake passage 27. Therefore, the blow-by gas in the engine body 13 is introduced into the intake passage portion 27b on the downstream side through the blow-by gas passage 36 (see arrow Y2 in FIG. 3). At this time, the flow rate of blow-by gas flowing through the blow-by gas passage 36 is controlled by a PCV valve 40 (described later).

  Further, as the blow-by gas is introduced into the intake passage portion 27b on the downstream side from the engine body 13 through the blow-by gas passage 36, the backflow prevention valve 32 is opened. Thus, fresh air in the intake passage portion 27a upstream of the intake passage 27 is introduced into the engine body 13 through the fresh air introduction passage 30 (see arrow Y1 in FIG. 3). Then, the fresh air introduced into the engine body 13 is introduced into the downstream intake passage portion 27b through the blow-by gas passage 36 together with the blow-by gas (see arrow Y2 in FIG. 3). As described above, the inside of the engine body 13 is scavenged.

  Further, when the engine 12 is at a high load, the opening degree of the throttle valve 24a becomes large. Therefore, the pressure in the intake passage portion 27b on the downstream side of the intake passage 27 approaches the atmospheric pressure. Therefore, the blow-by gas in the engine main body 13 becomes difficult to be introduced into the intake passage portion 27b on the downstream side, and the pressure in the engine main body 13 also approaches atmospheric pressure. For this reason, the flow rate of fresh air introduced into the engine body 13 from the upstream intake passage portion 27a through the fresh air introduction passage 30 is also reduced. Further, by closing the check valve 32, the back flow of blow-by gas from the engine body 13 to the fresh air introduction passage 30 (see arrow Y3 in FIG. 3) is prevented.

  The blow-by gas passage 36 is provided with a PCV valve 40 as a flow rate control valve for controlling the flow rate of blow-by gas. The PCV valve 40 controls or measures the flow rate of the blowby gas in accordance with the differential pressure between the upstream pressure and the downstream pressure of the blowby gas, thereby preventing a sudden change in the flow rate of the blowby gas due to a sudden change in the differential pressure.

Next, the PCV valve 40 will be described. FIG. 1 is a sectional view showing a PCV valve, and FIG. 2 is a front view of the same. For convenience of explanation, the left side of FIG. 1 is the front side, and the right side is the rear side.
As shown in FIG. 1, the case 42 of the PCV valve 40 is made of, for example, resin and is formed in a hollow cylindrical shape. The hollow portion in the case 42 is a gas passage 50 extending in the axial direction (left-right direction in FIG. 1). Further, the rear end portion (right end portion in FIG. 1) of the case 42 is connected to a passage portion on the upstream side of the blow-by gas passage 36 (see FIG. 3). Further, the front end portion (left end portion in FIG. 1) of the case 42 is connected to a passage portion on the downstream side of the blow-by gas passage 36. Further, the rear end portion of the case 42 may be connected to the blow-by gas outlet 18b (see FIG. 3) of the cylinder head cover 18. Therefore, the blow-by gas that is a fluid flows through the gas passage 50. The gas passage 50 corresponds to a “fluid passage” in this specification.

  The case 42 is configured by joining a pair of front and rear case halves 42a and 42b that are divided into two in the axial direction (front-rear direction). A valve seat portion 43 that protrudes radially inward in a flange shape is formed concentrically at the rear end portion of the front case half 42a. In addition, a hollow cylindrical upstream wall surface 45 is formed in the rear case half 42 b, that is, on the gas inflow side (right side in FIG. 1) of the gas passage 50. The inside of the passage wall surface 45 on the upstream side is the passage portion 52 on the upstream side. A hollow cylindrical downstream wall surface 47 is formed in front of the valve seat 43 of the front case half 42a, that is, on the gas outflow side (left side in FIG. 1). The inside of the passage wall surface 47 on the downstream side is a passage portion 54 on the downstream side. Further, the hollow hole in the valve seat portion 43 is a measuring hole 53 that allows the upstream passage portion 52 and the downstream passage portion 54 to communicate with each other. Further, a throttle wall portion 48 is formed concentrically at the rear end portion of the rear case half 42b so as to protrude in a radially inward direction from the upstream passage wall surface 45 in a flange shape. The circular hollow hole in the throttle wall 48 serves as an inlet 51 for the gas passage 50 (specifically, the upstream passage portion 52).

  In the case 42, that is, in the gas passage 50, the valve body 60 is disposed so as to be movable back and forth in the axial direction (left and right direction in FIG. 1), that is, movable in the axial direction. The valve body 60 is made of, for example, a resin and mainly includes a valve main body 61 formed in a substantially cylindrical shape. A distal end portion (front end portion) 66 of the valve main body portion 61 is formed in a tapered shape, and is inserted from the upstream passage portion 52 of the gas passage 50 toward the downstream passage portion 54 via the measuring hole 53. ing. A stepped tapered measuring surface 62 is formed concentrically on the outer peripheral surface of the valve body 61 corresponding to the measuring hole 53. Further, the measuring portion 70 is configured by the measuring hole 53 (specifically, the inner peripheral surface) and the measuring surface 62 of the valve body 60. Therefore, as the valve body 60 moves backward (moves to the right in FIG. 1), the effective opening area of the measuring portion 70, that is, the passage cross-sectional area is increased. Conversely, as the valve body 60 moves forward (moves to the left in FIG. 1), the passage cross-sectional area of the measuring portion 70 is reduced. The valve body 60 corresponds to the “valve body” in this specification.

  A guide flange 63 is formed concentrically at the rear end portion (right end portion in FIG. 1) of the valve main body portion 61 so as to protrude radially outward. The outer peripheral surface of the guide flange 63 is capable of sliding contact with the passage wall surface 45 on the upstream side of the rear case half 42b. Further, an appropriate number (three are shown in FIG. 2) of notches 64 that allow the passage of blow-by gas is formed on the outer periphery of the guide flange 63. Further, the guide flange 63 abuts against the throttle wall 48 of the rear case half 42 b in the case 42 at the last retracted position of the valve body 60.

  As shown in FIGS. 1 and 2, a stepped portion 67 located on the distal end side (front side) of the measuring surface 62 is formed on the base side (right side in FIG. 1) of the distal end portion 66 of the valve main body 61. Has been. Further, a plurality of rib-shaped spring guides 56 (three are shown in FIG. 2) projecting radially are formed on the passage wall surface 47 on the downstream side. Each spring guide 56 extends linearly in the axial direction of the downstream passage wall surface 47. Further, the inner end surface of each spring guide 56 is formed by a cross-sectional arc-shaped surface having an inner diameter slightly larger than the outer diameter of a coil spring 72 (described later), and serves as a guide surface for the coil spring 72. Further, the inner end surface of each spring guide 56 is formed by a cross-sectional arc-shaped surface having the same or substantially the same inner diameter as the inner diameter of the measuring hole 53. A protruding spring seat portion 57 projects from the inner end surface of the front end portion of each spring guide 56.

  As shown in FIG. 1, a coil spring 72 is interposed between the case half 42 a on the front side of the case 42 and the valve body 60 in the passage portion 54 on the downstream side of the gas passage 50. . A cylindrical coil spring is used for the coil spring 72. Further, the rear end portion of the coil spring 72 (specifically, the end winding portion 72 a at the movable side end portion) is locked to the stepped portion 67 of the valve body 60. The end winding portion 72 a is reduced in diameter so as to correspond to the outer diameter of the stepped portion 67 of the valve body 60, and is fitted to the stepped portion 67. The front end portion of the coil spring 72 (specifically, the end winding portion of the fixed side end portion) is locked to the spring seat portion 57 of each spring guide 56. The coil spring 72 always urges the valve body 60 in the backward direction (rightward in FIG. 1), that is, in the direction in which the passage sectional area of the measuring unit 70 increases. Each spring guide 56 prevents the coil spring 72 from being displaced in the radial direction, bent and deformed.

  Next, the operation of the PCV valve 40 will be described. When the passage portion 54 on the downstream side of the passage portion 52 on the upstream side of the gas passage 50 in the case 42 becomes a low pressure (negative pressure), the blow-by gas flows into the passage portion 52 on the upstream side from the inlet 51, It flows out through the measurement hole 53 and the passage portion 54 on the downstream side. At this time, the valve body 60 moves forward and backward (in the axial direction) according to the differential pressure between the upstream pressure of the upstream passage portion 52 and the downstream pressure of the downstream passage portion 54 (including the biasing force of the coil spring 72). Move to). Thereby, the flow rate of the blow-by gas flowing through the gas passage 50 is controlled, that is, measured. Specifically, when the upstream pressure is larger than the downstream pressure and the differential pressure between the upstream pressure and the downstream pressure is large, the valve body 60 is moved forward against the urging force of the coil spring 72, so that the measuring unit Since the passage cross-sectional area of 70 is reduced, the flow rate of blow-by gas is reduced. Further, when the differential pressure between the upstream pressure and the downstream pressure is reduced, the valve body 60 is retracted by the urging force of the coil spring 72, whereby the passage cross-sectional area of the measuring unit 70 is increased. The flow rate increases. As described above, the flow rate of the blow-by gas flowing through the gas passage 50 is controlled by increasing or decreasing the passage cross-sectional area of the measuring unit 70.

  According to the PCV valve 40 described above, since the distal end portion 66 of the valve body 60 is elastically held by the coil spring 72, the radial deflection of the distal end portion 66 of the valve body 60 can be prevented. As a result, the radial swing width and swing speed at the tip 66 of the valve body 60 are reduced, the operational stability of the valve body 60 is improved, and the impact force and sound of the impact are reduced by preventing the measurement surface 62 from colliding with the measurement hole 53. Reduction, improvement of durability by preventing wear of the measurement hole 53 and / or the measurement surface 62 can be achieved.

  The valve body 60 is formed with a flange-shaped guide flange 63 that is in sliding contact with the passage wall surface 45 upstream of the measuring portion 70 in the gas passage 50. Accordingly, the rear end portion of the valve body 60 is supported by the sliding contact of the guide flange 63 with the upstream passage wall surface 45 in the gas passage 50, thereby preventing radial deflection of the rear end portion of the valve body 60. be able to.

  Further, the PCV valve 40 is used in the blow-by gas reduction device 10 (see FIG. 3) of the internal combustion engine. Therefore, vibration in the radial direction of the tip portion 66 of the valve body 60 in the PCV valve 40 can be prevented.

[Embodiment 2]
Embodiment 2 will be described. Since the embodiment after this embodiment is a modification of the first embodiment, the changed portion will be described, and a duplicate description will be omitted. FIG. 4 is a cross-sectional view showing the PCV valve.
As shown in FIG. 4, in this embodiment, the valve body 61 of the valve body 60 in the first embodiment (see FIG. 1) is in sliding contact with the inner peripheral surface of the measuring hole 53 and radially. A plurality of (for example, three) guide ribs 68 projecting are formed. Each guide rib 68 extends in the axial direction of the valve body 60. Accordingly, the central portion of the valve body 60 is supported by the sliding contact of the guide ribs 68 with the inner peripheral surface of the measuring hole 53, whereby the radial deflection of the central portion of the valve body 60 can be prevented.

[Embodiment 3]
A third embodiment will be described. This embodiment is a modification of the first embodiment. FIG. 5 is a cross-sectional view showing the PCV valve.
As shown in FIG. 5, this embodiment uses a drum-shaped coil spring 74 instead of the coil spring 72 in the first embodiment (see FIG. 1). Accordingly, since the intermediate portion in the axial direction of the drum-shaped coil spring 74 is reduced in diameter, the contact of the coil spring 74 with the inner end surface (guide surface) of each spring guide 56 of the case 42 is reduced, and the contact It is possible to prevent a change in flow rate due to an increase in wear and frictional resistance. The end winding part 74 a at the rear end of the coil spring 74 is reduced in diameter so as to correspond to the outer diameter of the stepped part 67 of the valve body 60, and is fitted to the stepped part 67.

[Embodiment 4]
A fourth embodiment will be described. This embodiment is a modification of the first embodiment. FIG. 6 is a cross-sectional view showing a PCV valve.
As shown in FIG. 6, in this embodiment, a conical coil spring 76 is used instead of the coil spring 72 in the first embodiment (see FIG. 1). Accordingly, since the diameter of the conical coil spring 76 is reduced from one end side (front end side) to the other end side (rear end side), the inner end surface (guide surface) of each spring guide 56 of the case 42 is reduced. The contact of the coil spring 76 can be reduced, and the change in flow rate due to wear and frictional resistance due to the contact can be prevented. The end winding portion 76 a at the rear end of the coil spring 76 corresponds to the outer diameter of the stepped portion 67 of the valve body 60 and is fitted to the stepped portion 67.

[Embodiment 5]
Embodiment 5 will be described. This embodiment is a modification of the first embodiment. FIG. 7 is a sectional view showing the PCV valve, and FIG. 8 is a front view of the same.
As shown in FIGS. 7 and 8, in this embodiment, the plurality of rib-shaped spring guides 56 in the first embodiment (see FIGS. 1 and 2) are changed to cylindrical spring guides. . That is, the passage wall surface 47 on the downstream side of the case 42 is formed with an inner diameter slightly larger than the outer diameter of the coil spring 72. A peripheral wall portion having a passage wall surface 47 on the downstream side is set to the spring guide 80. For this reason, the passage wall surface 47 on the downstream side also serves as the guide surface of the coil spring 72. Further, a spring seat portion 81 that protrudes radially inward in a flange shape is formed concentrically at the front end portion of the spring guide 80. A hollow hole in the spring seat portion 81 serves as an outlet of the gas passage 50 (specifically, the downstream passage portion 54). Further, the coil spring 72 in the present embodiment can be replaced with the drum-shaped coil spring 74 (see FIG. 5) in the third embodiment or the conical coil spring 76 (see FIG. 6) in the fourth embodiment.

[Embodiment 6]
Embodiment 6 will be described. This embodiment is a modification of the fifth embodiment. FIG. 9 is a sectional view showing the PCV valve, and FIG. 10 is a front view of the same.
As shown in FIGS. 9 and 10, the present embodiment is a spring in which the spring seat portion 81 in the fifth embodiment (see FIGS. 7 and 8) is formed separately from the case half 42 a on the front side of the case 42. The sheet member 83 is changed. That is, the spring seat member 83 is formed in an annular shape, and is attached to the front end portion of the passage wall surface 47 on the downstream side of the case 42 through attachment means such as press fitting, adhesion, and welding. The spring seat member 83 corresponds to a “spring seat portion” in this specification. Further, the coil spring 72 in the present embodiment can be replaced with the drum-shaped coil spring 74 (see FIG. 5) in the third embodiment or the conical coil spring 76 (see FIG. 6) in the fourth embodiment.

  The present invention is not limited to the above-described embodiment, and modifications can be made without departing from the gist of the present invention. For example, the present invention can be applied not only to the PCV valve 40 but also to a flow control valve that controls the flow rate of fluid other than blow-by gas. In the above embodiment, the valve seat portion 43 having the measuring hole 53 is formed in the case 42 (in the above embodiment, the front case half 42a). However, the valve seat 43 is formed separately from the case 42 and has the measuring hole. The sheet member may be assembled to the case 42. For example, the valve seat member can be sandwiched between the case halves 42a and 42b, or can be attached to the front case halves 42a through attachment means such as press-fitting, bonding, and welding.

10 ... Blow-by gas reduction device 12 ... Engine (internal combustion engine)
40 ... PCV valve (flow control valve)
42 ... Case 50 ... Gas passage (fluid passage)
53 ... Measuring hole 57 ... Spring seat part 60 ... Valve body (valve body)
62 ... Measuring surface 63 ... Guide flange 66 ... Tip 68 ... Guide rib 70 ... Measuring unit 72 ... Coil spring (cylindrical coil spring)
74 ... Coil spring (Drum-shaped coil spring)
76 ... Coil spring (conical coil spring)
81 ... Spring seat part 83 ... Spring seat member (spring seat part)

Claims (7)

A case with a fluid passage;
A valve body provided in the fluid passage so as to be movable back and forth in the axial direction;
A coil spring for urging the valve body in the backward direction,
A measuring part is constituted by a measuring hole formed in the middle of the fluid passage and a measuring surface formed in the valve body,
A flow rate control valve that controls a flow rate of fluid by adjusting a passage cross-sectional area of the metering unit by movement of the valve body in an axial direction;
The coil spring is interposed between a tip end portion of the valve body and a spring seat portion disposed downstream of the tip end portion of the valve body in the fluid passage of the case ,
The flow control valve according to claim 1, wherein an end of the coil spring on the valve body side is fitted to a tip of the valve body . The flow control valve according to claim 1,
A stepped portion is formed at the tip of the valve body,
A flow rate control valve characterized in that the end winding portion on the valve element side of the coil spring has a reduced diameter and is fitted to a stepped portion . The flow control valve according to claim 1 or 2 ,
A flow rate control valve using a drum-shaped coil spring as the coil spring. The flow control valve according to claim 1 or 2 ,
A flow rate control valve using a conical coil spring as the coil spring. The flow control valve according to any one of claims 1 to 4 ,
The flow rate control valve according to claim 1, wherein the valve body is formed with a plurality of guide ribs that are in sliding contact with the inner peripheral surface of the measuring hole and project radially. A flow control valve according to any one of claims 1 to 5 ,
The flow rate control valve according to claim 1, wherein a flange-shaped guide flange is formed on the valve body so as to be in sliding contact with a passage wall surface on the upstream side of the measuring portion in the fluid passage. The flow control valve according to any one of claims 1 to 6 ,
A flow control valve, which is a PCV valve used in a blow-by gas reduction device for an internal combustion engine.

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