JP2007198279A - Composite valve, and blowby gas reducing device of engine equipped with composite valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce channel resistance to the utmost when fluid flows in a forward direction, to prevent a fluid backflow, and to prevent fluid on a downstream side from being led to reversely flow frequently to an upstream side by relieving pressure only when pressure is increased to a predetermined value or more on the downstream side of a channel. <P>SOLUTION: This composite valve has a backflow preventing part which is mounted in a fluid passage 24, does not block a fluid flow when fluid flows in the forward direction from the upstream side of the passage 24 to the downstream side thereof, and blocks the fluid flow when fluid flows in a reverse direction, and a pressure regulating part designed that when pressure on the downstream side of the backflow preventing part is increased to the predetermined value or more, a channel bypassing the backflow preventing part is opened by the pressure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composite valve including a backflow prevention unit and a pressure adjusting unit, and an engine blow-by gas reduction device including the composite valve.

Patent Document 1 discloses a technique related to an engine blow-by gas reduction device including the above-described composite valve.
The blow-by gas reduction device 110 is a device that returns blow-by gas leaked from each cylinder (not shown) of the engine 100 to the crank chamber 100c to the intake device 102, as shown in FIG. 6 (A). The blow-by gas reduction device 110 introduces air that makes the crank chamber 100c of the engine 100 and the surge tank 108 of the intake device 102 communicate with each other, and the upstream side of the throttle valve of the intake pipe 104 and the crank chamber 100c. And a passage 115.
Blow-by gas in the crank chamber 100c of the engine is sucked into the surge tank 108 of the intake device 102 through the blow-by gas reduction passage 113, and is supplied to each cylinder of the engine together with combustion air through the intake manifold 109. In addition, air that has passed through the air cleaner 105 is supplied to the crank chamber 100c of the engine that has become negative pressure due to suction of blow-by gas by the air introduction passage 115. Further, a composite valve 120 having a function as a safety valve when the pressure in the crank chamber 100c rises due to clogging of the blow-by gas reduction passage 113 and a function of suppressing back flow is attached in the middle of the air introduction passage 115. It has been.

As shown in FIG. 6B, the composite valve 120 includes a cylindrical housing 121 and a conical partition plate 123 that partitions the housing 121 into an inlet side and an outlet side. The partition plate 123 is formed with a plurality of openings 125 that allow the inlet chamber 122 and the outlet chamber 124 to communicate with each other at an upper portion and a lower portion, and the upper opening 125 is a first disc-shaped rubber plate from the outlet chamber 124 side. It is blocked by the valve 127. Further, the opening 125 at the lower portion of the partition plate 123 is closed from the inlet chamber 122 side by a second disc-like valve 129 made of rubber.
For this reason, when the air that has passed through the air cleaner 105 is supplied to the crank chamber 100c of the engine through the air introduction passage 115, the air flow is upstream of the rubber-made first disc valve 127 (on the inlet chamber 122 side). , The air passes through the gap between the first disk-shaped valve 127 and the opening 125. Note that the back flow of the fluid from the crank chamber 100c is restricted by the first disc-shaped valve 127 and the second disc valve 129 when the pressure in the crank chamber 100c is low. That is, the composite valve 120 has a function similar to a check valve.
Further, when the pressure in the crank chamber 100c of the engine increases, the fluid flowing out from the crank chamber 100c causes the rubber second disc-shaped valve 129 to be pressed and deformed from the downstream side (the outlet chamber 124 side). The fluid passes through the gap between the second disk-shaped valve 129 and the opening 125. Thereby, the composite valve 120 has a function as a safety valve.

Japanese Patent Laid-Open No. 7-63036

However, in the composite valve 120 described above, when air is supplied to the crank chamber 100c of the engine, the air presses and deforms the first disc-shaped valve 127 made of rubber from the upstream side (the inlet chamber 122 side). Since it is the structure which opens the opening 125, there exists a problem that the pressure loss in the composite valve 120 is large, and air cannot flow easily.
On the contrary, when the pressure in the crank chamber 100c of the engine rises, even when the pressure is relatively low, the second disc valve 129 made of rubber is deformed and the opening 125 is opened. There is a problem that it is frequently returned to the upstream side of the throttle valve 107.

  The present invention has been made to solve the above-mentioned problems, and the technical problem of the present invention is to reduce the flow resistance as much as possible when the fluid flows in the forward direction and to prevent the back flow of the fluid. thing. Furthermore, the pressure is allowed to escape only when the pressure rises above a predetermined value on the downstream side of the flow path, so that the downstream fluid does not flow back to the upstream side frequently.

The above-described problems are solved by the inventions of the claims.
The invention of claim 1 is configured to be attached to a fluid passage, and when the fluid flows in the forward direction from the upstream side to the downstream side of the passage, the fluid flows in the reverse direction without blocking the flow. When the pressure on the downstream side of the backflow prevention unit rises above a predetermined value, a flow path that bypasses the backflow prevention unit is opened by the pressure And a pressure adjusting unit configured.

According to the present invention, when the fluid flows in the forward direction from the upstream side to the downstream side of the flow path, the backflow prevention unit does not block the flow, so that the flow path resistance can be minimized. Further, when the fluid is about to flow in the reverse direction, the flow is blocked, so that the backflow of the fluid can be prevented.
Furthermore, when the pressure on the downstream side of the backflow prevention unit rises above a predetermined value, the pressure adjustment unit is configured to open a flow path that bypasses the backflow prevention unit with the pressure. The bypass flow path does not open when the pressure is less than a predetermined value. For this reason, the fluid on the downstream side does not flow back to the upstream side frequently, and it is possible to ensure the safety of the equipment reliably when necessary.

  According to the invention of claim 2, the backflow prevention unit includes a backflow prevention main body member that closes an opening of a flow passage formed in the housing of the composite valve, a fluid passage formed in the backflow prevention main body member, and a fluid passage therefor The valve body opens the fluid passage when the fluid flows in the forward direction, and the valve body closes the fluid passage when the fluid tries to flow in the reverse direction. And when the backflow prevention body member receives a pressure greater than or equal to a predetermined value from the downstream side, the backflow prevention body member is displaced upstream to open the opening of the flow path. The present invention is characterized in that a flow path that bypasses the backflow prevention unit is allowed to be formed.

According to the invention of claim 3, the valve body of the backflow prevention portion receives a pressing force from the forward direction of the fluid and moves in a direction to open the fluid passage of the backflow prevention main body member, and the pressing force from the reverse direction of the fluid In response, the fluid passage of the backflow prevention main body member is returned to a closed position.
According to the invention of claim 4, the flow path (bypass flow path) that bypasses the back flow prevention portion is closed by pressing the sealing surface of the back flow prevention main body member against the opening edge of the flow path by elastic force. Features. For this reason, the bypass channel can be closed with a constant pressing force.
According to the invention of claim 5, the valve body of the backflow prevention portion is a sphere, the backflow prevention main body member is formed in a disc shape, and a fluid passage is formed in the center of the backflow prevention main body member. To do. Thus, since the valve body is a spherical body, the valve body is easily moved by receiving the force of the fluid. Therefore, a large force is not required when the valve body opens the fluid passage of the backflow prevention main body member. For this reason, even when the fluid gently flows in the forward direction, the fluid passage of the backflow preventing main body member can be easily opened.

A sixth aspect of the present invention is an engine blow-by gas reduction device comprising the composite valve according to any one of the first to fifth aspects, wherein the throttle valve downstream side of the intake pipe for supplying combustion air to the engine and the engine A blow-by gas reduction passage that communicates with the crank chamber, an air introduction passage that communicates the throttle valve upstream side of the intake pipe and the crank chamber, and the composite valve has an intake pipe side of the engine as an upstream side. It is attached to the air introduction passage as described above.
For this reason, when air flows in the forward direction from the intake pipe to the crank chamber of the engine, the flow path resistance can be minimized. Further, when the gas tries to flow backward from the crank chamber to the intake pipe side, the flow is blocked, so that the back flow of the fluid can be prevented.
Furthermore, when the pressure on the downstream side (crank chamber) of the backflow prevention unit rises above a predetermined value, the pressure adjustment unit is configured to open a flow path that bypasses the backflow prevention unit with that pressure. The bypass flow path does not open when the pressure in the crank chamber is below a predetermined value. For this reason, the fluid in the crank chamber does not flow back to the upstream side frequently.

  According to the present invention, when the fluid flows in the forward direction from the upstream side to the downstream side of the flow channel, the flow channel resistance can be reduced as much as possible, and the back flow of the fluid can be prevented. Furthermore, when the pressure rises above a predetermined pressure on the downstream side of the flow path, the pressure can be released to the upstream side, so that the safety of the facility can be reliably ensured.

[Embodiment 1]
Hereinafter, based on FIGS. 1-5, the composite valve which concerns on Embodiment 1 of this invention is demonstrated. The composite valve according to the present embodiment is a valve used in a blow-by gas reduction device for an automobile engine. Here, FIG. 1 is a schematic diagram showing a blow-by gas reduction device including a composite valve according to the present embodiment and an intake device of an engine, and FIGS. 2 and 3 are a longitudinal sectional view and a plan view of the composite valve, FIG. Is a graph showing the flow characteristics of the composite valve. FIG. 5 is a schematic view showing a modification of the engine intake device and blow-by gas reduction device.

<About the engine intake device 10>
First, an outline of the engine intake device 10 will be described.
The engine intake device 10 is a device for supplying combustion air to each cylinder (not shown) of the engine 1 and includes an intake pipe 12 that is a passage of combustion air, as shown in FIG. An air cleaner 14, a flow meter 15, and a throttle valve 17 are attached to the intake pipe 12 in order from the upstream side, and an accelerator petal (not shown) in which the valve body 17 v of the throttle valve 17 is installed in the cab of the automobile. It is configured to be linked with the operation of. Further, the intake pipe 12 is provided with a surge tank 18 on the downstream side of the throttle valve 17, and combustion air is supplied to each cylinder by the intake manifold 19 via the surge tank 18.

<About the engine blow-by gas reduction device 20>
Next, the blow-by gas reduction device 20 for the engine will be described.
The blow-by gas reduction device 20 is a device that prevents blow-by gas leaked from each cylinder of the engine 1 into the crank chamber 1c to the intake device 10 to prevent release to the atmosphere. As shown in FIG. 1, the blow-by gas reduction device 20 includes a blow-by gas reduction passage 22 that connects the crank chamber 1 c of the engine 1 and the surge tank 18 of the intake device 10, and the crank chamber 1 c of the engine 1 and the intake pipe 12. An air introduction passage 24 that communicates with the upstream side of the throttle valve is provided.
Here, the throttle valve upstream side of the intake pipe 12 is maintained at a pressure (about 0 KPa) substantially equal to the atmospheric pressure. The pressure in the surge tank 18 is maintained at about −70 KPa when the opening of the throttle valve 17 is almost zero (idling state). As the opening of the throttle valve 17 increases, the atmospheric pressure ( (Approx. 0 KPa). For this reason, the blow-by gas in the crank chamber 1c is easily sucked into the surge tank 18 when the opening of the throttle valve 17 is close to zero (idling state). However, the blow-by gas reduction passage 22 is provided with a flow rate adjusting valve 22f so that the suction amount of the blow-by gas does not change suddenly due to a change in differential pressure between the crank chamber 1c and the surge tank 18.

The blow-by gas introduced into the surge tank 18 by the blow-by gas reduction passage 22 is supplied to each cylinder of the engine 1 through the intake manifold 19 together with the combustion air, where it is burned again.
In addition, air that has passed through the air cleaner 14 is supplied into the crank chamber 1c of the engine 1 that has become negative pressure due to the blow-by gas flowing out through the air introduction passage 24. Further, a composite valve 30 is attached in the middle of the air introduction passage 24. The composite valve 30 has a check valve function that prevents the blow-by gas from flowing backward from the crank chamber 1c side to the intake pipe 12 side, and the pressure in the crank chamber 1c exceeds a predetermined value due to clogging of the blow-by gas reduction passage 22 or the like. It has a safety valve function that opens the flow path when it rises.

<About compound valve 30>
Next, the structure of the composite valve 30 is demonstrated based on FIGS. Here, FIG. 2 (A) and FIG. 3 show the longitudinal cross-sectional views of the composite valve 30, and FIG. 2 (B) shows the BB arrow line view of FIG. 2 (A). FIG. 4 is a graph showing the relationship between the pressure in the crank chamber 1 c of the engine 1 and the flow rate of the composite valve 30.
As shown in FIG. 2 (A) and the like, the composite valve 30 includes a housing 30h including an input side housing piece 32 and an output side housing piece 34. The entry-side housing piece 32 is composed of a small-diameter tube portion 321 and a large-diameter flange portion 322 formed at the shaft end (rear end) of the tube portion 321, and both 321 and 322 are coaxial. Is positioned. The pipe body portion 321 is a portion that becomes an inlet pipe of the composite valve 30 and is connected to the upstream side of the air introduction passage 24 described above. The flange portion 322 has a ring-shaped recess 322h coaxially formed on the rear end side (the side opposite to the tube portion 321), and the ring-shaped recess 322h communicates with the internal passage 321t of the tube portion 321. ing. The inner diameter dimension of the ring-shaped recess 322h in the flange part 322 is set to a value sufficiently larger than the inner diameter dimension of the internal passage 321t of the tube part 321.
Further, a circular groove 322m is formed on the rear end surface 322z of the flange portion 322 so as to surround the ring-shaped recess 322h and coaxially with the recess 322h.

The outlet housing piece 34 is formed in a shape that is substantially symmetrical with the above-described inlet housing piece 32 in the front-rear direction. The outlet housing piece 34 includes a tube portion 341 and a flange portion 342 formed at the shaft end (front end) of the tube portion 341, and both 341 and 342 are positioned coaxially. The tube part 341 is a part that becomes an outlet pipe of the composite valve 30, and is connected to the downstream side of the air introduction passage 24 described above. The flange portion 342 is formed with a ring-shaped recess 342h coaxially on the tip side (opposite to the tube portion 341), and the inner diameter of the ring-shaped recess 342h is the same as that of the recess 322h of the inlet housing piece 32. The value is set equal to the inner diameter. Furthermore, a plurality of linear grooves 342x (see dotted lines) extending in the axial direction are formed in the circumferential direction on the inner peripheral surface of the ring-shaped recess 342h.
A valve body support portion 344 that protrudes in an inner flange shape from the inner peripheral surface 341w of the tube body portion 341 is formed in the tube body portion 341 of the outlet housing piece 34 at a position near the rear end portion. Furthermore, a plurality of linear protrusions 341y extending in the axial direction from the position of the valve body support part 344 to the position of the recess part 342h of the flange part 342 are formed on the inner peripheral surface 341w of the tube part 341 in the circumferential direction. . The linear protrusion 341y is a member that guides a spherical valve body 41, which will be described later, in the axial direction from the position of the valve body support portion 344 to the position of the recess portion 342h of the flange portion 342, and the valve body 41 is in the tube body portion 341. In this state, the gas can pass through the groove-like flow path 341x (see the dotted line) formed between the straight ridges 341y.

As shown in FIG. 2 (B), the valve body support portion 344 has a circular opening 344c at the center, and a tapered surface 344t (see FIG. 2 (A)) on which the valve body 41 fits on the periphery of the circular opening 344c. Is formed. In addition, a substantially fan-shaped opening 344s communicating with the groove-like flow path 341x formed between the respective linear protrusions 341y is formed in the peripheral portion of the valve body support portion 344 by the same number as the groove-like flow paths 341x. Has been.
Further, a thin cylindrical portion 342e is formed on the outer peripheral edge of the front end surface 342f of the flange portion 342 of the outlet housing piece 34. Here, the diameter of the cylindrical portion 342 e is set to a value equal to the diameter of the circular groove 322 m of the entry-side housing piece 32. The cylindrical portion 342e of the outlet housing piece 34 is fitted into the circular groove 322m of the inlet housing piece 32, and the front end surface 342f of the flange portion 342 of the outlet housing piece 34 is located behind the flange portion 322 of the inlet housing piece 32. The housing 30h is completed while being in surface contact with the end face 322z.

In the housing 30h, a substantially disc-shaped backflow prevention main body member 43 is axially displaceable in a space S formed by the recess 322h of the entrance housing piece 32 and the recess 342h of the exit housing piece 34. It is stored. The backflow prevention main body member 43 includes a disk part 435 and a short pipe part 437 that protrudes axially forward (rightward in FIG. 2A) from the center of the disk part 435, and the short pipe part. A fluid passage 438 is formed so as to penetrate from 437 to the disk portion 435. The disk portion 435 of the backflow prevention main body member 43 is formed with a seal surface 435s that contacts the bottom surface 342b of the recess 342h of the outlet housing piece 34 and closes each of the groove-shaped channels 341x described above from the axial direction. . Further, a tapered surface 435t is formed on the seal surface 435s so that the spherical valve body 41 abuts on the peripheral portion of the fluid passage 438.
The spherical valve body 41 is housed in the tube body portion 341 of the outlet housing piece 34, and the position of the valve body support portion 344 of the tube body portion 341 (see FIG. 2A, two-dot chain line). To a position (see a solid line in FIG. 2A) that contacts the tapered surface 435t of the disk portion 435 of the backflow prevention main body member 43.
Further, around the short pipe portion 437 of the backflow prevention main body member 43, the backflow prevention main body member 43 is pressed rearward (leftward in FIG. 2A) so that the seal surface 435s of the disk portion 435 is disposed on the outlet housing. A coil spring 47 is mounted so as to contact the bottom surface 342b of the concave portion 342h of the piece 34.

<Operation of Compound Valve 30>
Next, the operation of the composite valve 30 will be described.
When fluid flows from the inlet to the outlet (forward direction) with respect to the composite valve 30, the fluid that has flowed into the internal passage 321t of the tube body portion 321 flows into the fluid passage 438 of the backflow prevention main body member 43, The valve body 41 is pressed. As a result, the valve body 41 moves rearward (in the direction of the valve body support portion 344) while rotating, and moves away from the tapered surface 435t of the disk portion 435 of the backflow prevention main body member 43. As a result, the fluid passage 438 of the backflow prevention main body member 43 is opened, and the fluid flows from the fluid passage 438 to the groove of the tube portion 341 of the outlet housing piece 34 as shown by the two-dot chain line in FIG. The flow path 341x and the substantially fan-shaped opening 344s of the valve body support portion 344, and flows out from the outlet of the composite valve 30.
Further, when the fluid tries to flow backward, the fluid that flows in from the outlet of the composite valve 30 through the circular opening 344c of the valve body support 344 presses the valve body 41 forward (rightward in FIG. 2A), The valve body 41 comes into contact with the tapered surface 435t of the disk portion 435 of the backflow prevention main body member 43 (see the solid line in FIG. 2A). As a result, the fluid passage 438 of the backflow prevention main body member 43 is closed. Further, in this state, the seal surface 435 s of the disk portion 435 of the backflow prevention main body member 43 is pressed against the bottom surface 342 b of the recess 342 h of the outlet housing piece 34 by the spring force of the coil spring 47. As a result, the groove-shaped flow path 341x of the tube portion 341 of the outlet housing piece 34 is closed.
That is, since the fluid passage 438 of the backflow prevention main body member 43 is closed and the groove-like flow path 341x of the tube portion 341 of the outlet housing piece 34 is closed, the fluid backflow is prevented. Thus, the backflow prevention main body member 43, the fluid passage 438, the valve body 41, and the like correspond to the backflow prevention unit of the present invention.

However, when the pressure on the downstream side rises from this state and the pressure exceeds a predetermined value, the fluid causes the valve body 41 and the backflow prevention main body member 43 to become the spring force of the coil spring 47 as shown in FIG. Displace it upstream (forward). As a result, the seal surface 435 s of the disk portion 435 of the backflow prevention main body member 43 is separated from the bottom surface 342 b of the concave portion 342 h of the outlet housing piece 34, and the groove-like channel 341 x of the tube portion 341 of the outlet housing piece 34 is opened. . Then, the downstream fluid flows into the space S of the housing 30h via the groove-shaped channel 341x (see arrow). Further, the fluid that has flowed into the space S bypasses the backflow prevention main body member 43 through the linear groove 342x formed in the inner peripheral surface of the recess 342h of the outlet housing piece 34, and flows out upstream.
That is, the seal surface 435s of the backflow prevention main body member 43, the bottom surface 342b of the recess 342h of the outlet housing piece 34, the groove-like flow path 341x, the straight groove 342x, and the like correspond to the pressure adjusting portion of the present invention, and the coil spring 47 It corresponds to the elastic body of the present invention. Furthermore, the groove-shaped flow path 341x, the straight groove 342x, and the like correspond to a flow path (bypass flow path) that bypasses the backflow prevention unit of the present invention.

<Operation of Engine Blow-by Gas Reduction Device 20>
Next, the operation of the engine blow-by gas reduction device 20 will be described.
For example, when the engine 1 is close to idling, as described above, the pressure in the surge tank 18 has a value close to about −70 KPa, so the blow-by gas in the crank chamber 1 c of the engine 1 is blow-by gas reduction passage 22. Is sucked into the surge tank 18. And the inside of the crank chamber 1c of the engine 1 becomes a negative pressure. For this reason, the air that has passed through the air cleaner 14 is supplied into the crank chamber 1 c of the engine 1 by the air introduction passage 24. That is, air flows through the composite valve 30 in the direction from the inlet to the outlet (forward direction). At this time, air flows into the fluid passage 438 of the backflow prevention main body member 43 and presses the valve body 41. As a result, the valve body 41 moves rearward, the fluid passage 438 is opened, and the air passes from the fluid passage 438 to the groove-like flow path 341x of the tube portion 341 of the outlet housing piece 34 and the valve body support portion. It passes through the substantially sector-shaped opening 344 s 344 and flows out from the outlet of the composite valve 30.
FIG. 4 is a graph showing the characteristics of the composite valve 30, where the horizontal axis represents the pressure in the crank chamber 1 c and the vertical axis represents the gas flow rate flowing through the composite valve 30. That is, the composite valve 30 can flow air in the forward direction (from upstream to downstream) while the crank chamber 1c of the engine 1 is in a negative pressure (see characteristic I).

On the other hand, when the throttle valve 17 is opened and the engine 1 becomes a high load, the pressure in the surge tank 18 rises and approaches atmospheric pressure. For this reason, the blow-by gas in the crank chamber 1c of the engine 1 becomes difficult to be sucked into the surge tank 18 via the blow-by gas reduction passage 22, and the pressure in the crank chamber 1c becomes close to the atmospheric pressure. For this reason, the flow rate of air supplied to the crank chamber 1c through the air introduction passage 24 (the flow rate of air flowing in the forward direction through the composite valve 30) decreases (see characteristic II).
For example, when the pressure in the crank chamber 1c of the engine 1 becomes positive due to clogging of the blow-by gas reduction passage 22 or a reduction in the opening area, the gas or the like (fluid) in the crank chamber 1c passes through the air introduction passage 24. It tries to flow backward to the intake pipe 12 side. However, the fluid flowing in from the outlet of the composite valve 30 presses the valve body 41 forward (upstream direction), whereby the valve body 41 closes the fluid passage 438 of the backflow prevention main body member 43. Further, the seal surface 435 s of the disk portion 435 of the backflow prevention main body member 43 is pressed against the bottom surface 342 b of the concave portion 342 h of the outlet housing piece 34 by the spring force of the coil spring 47, so that the groove-like flow path 341 x of the tube portion 341 Is blocked. For this reason, the back flow of the fluid is prevented (see characteristic III).
However, when the pressure in the crank chamber 1c of the engine 1 rises above a predetermined value, the valve body 41 and the backflow prevention main body member 43 are moved upstream (frontward) against the spring force of the coil spring 47 by the fluid pressure. Displace. As a result, the seal surface 435 s of the disk portion 435 of the backflow prevention main body member 43 is separated from the bottom surface 342 b of the concave portion 342 h of the outlet housing piece 34, and the groove-like channel 341 x of the tube portion 341 is opened. Then, the downstream fluid flows into the space S of the housing 30h via the groove-shaped flow path 341x, bypasses the backflow prevention main body member 43 through the linear groove 342x, and escapes upstream (characteristic IV). reference). Thereby, trouble of the engine 1 is avoided.

<Advantages of the composite valve 30 according to this embodiment>
According to the composite valve 30 according to the present invention, the backflow prevention unit (the valve body 41, the backflow prevention main body member 43, etc.) does not block the flow when the fluid flows in the forward direction. it can. Further, when the fluid is about to flow in the reverse direction, the flow is blocked, so that the backflow of the fluid can be prevented.
Furthermore, when the pressure on the downstream side of the backflow prevention unit rises above a predetermined value, the pressure adjustment unit (backflow prevention main body member 43, coil spring 47, etc.) bypasses the backflow prevention unit with the pressure ( Since the groove-like flow path 341x of the tube body portion 341 is configured to open, the bypass flow path does not open when the downstream pressure is equal to or lower than a predetermined value. For this reason, the fluid on the downstream side does not flow back to the upstream side frequently, and the safety of the equipment can be ensured reliably when necessary.
In addition, since the peripheral edge of the backflow prevention main body member 43 is pressed against the opening edge of the groove-like flow path 341x by elastic force, the flow path (bypass flow path) that bypasses the backflow prevention section is closed, so that a constant push The bypass channel can be closed with pressure.
Moreover, since the valve body 41 is a spherical body, the valve body 41 is easily moved by receiving the force of the fluid. Therefore, when the valve body 41 opens the fluid passage 438 of the backflow prevention main body member 43, a large force is not required. For this reason, even when the fluid gently flows in the forward direction, the fluid passage 438 of the backflow preventing main body member 43 can be easily opened.

<Example of change>
In the present embodiment, the blow-by gas reduction device 20 including the composite valve 30 in which the backflow prevention unit and the pressure adjustment unit are integrated is illustrated. However, as illustrated in FIG. 5, the composite valve 30 is connected to the check valve 51 and the pressure. It is also possible to divide into the regulating valve 52. That is, when the pressure in the crank chamber 1c of the engine 1 is negative or slightly positive (characteristic I, characteristic II, characteristic III), the check valve 51 is operated, and the gas in the crank chamber 1c, etc. Prevent backflow of (fluid). When the pressure in the crank chamber 1c rises above a predetermined value (characteristic IV), the pressure adjustment valve 52 operates in a direction to open the flow path. This makes it possible to add a pressure adjustment valve 52 later to the existing blow-by gas reduction device 20 having only the check valve 51 and to take safety measures.
Further, in the present embodiment, an example in which the composite valve 30 is provided in the middle of the air introduction passage 24 of the blow-by gas reduction device 20 is shown, but the composite valve 30 can be provided in a device other than the blow-by gas reduction device 20. .

It is a schematic diagram showing the blow-by gas reduction apparatus provided with the compound valve concerning Embodiment 1 of the present invention, and an engine intake device. It is the longitudinal cross-sectional view (A figure) of a composite valve, and a top view (BB view figure (B figure) of A figure). It is a longitudinal cross-sectional view of a composite valve. It is a graph showing the flow characteristic of a compound valve. It is a schematic diagram showing the example of a change of an engine intake device and a blow-by gas reduction device. It is the schematic diagram (A figure) showing the blow-by gas reduction apparatus provided with the conventional composite valve, and the engine intake device, and the longitudinal cross-sectional view (B figure) of the said composite valve.

Explanation of symbols

20 Blow-by gas reduction device 22 Blow-by gas reduction passage 24 Air introduction passage 30 Composite valve 41 Valve body (backflow prevention part)
43 Backflow prevention body member (backflow prevention part, pressure adjustment part)
47 Coil spring (pressure adjusting part, elastic body)
438 Fluid passage 341x Groove channel (bypass channel)
342x Straight groove (Bypass channel)
342b Bottom of recess (pressure adjustment part)
435s Seal surface (pressure adjustment part)

Claims (6)

When the fluid tries to flow in the reverse direction without blocking the flow when the fluid flows in the forward direction from the upstream side to the downstream side of the passage in the configuration attached to the fluid passage, A backflow prevention unit that blocks
A pressure adjusting unit configured to open a flow path that bypasses the backflow prevention unit when the pressure on the downstream side of the backflow prevention unit rises above a predetermined value; and
A composite valve characterized by comprising: The composite valve according to claim 1,
The backflow prevention unit includes a backflow prevention main body member that closes an opening of a flow path formed in the housing of the composite valve, a fluid passage formed in the backflow prevention main body member, and a valve body that opens and closes the fluid passage. The valve body opens the fluid passage when the fluid flows in the forward direction, and the valve body closes the fluid passage when the fluid tries to flow in the reverse direction,
When the backflow prevention main body member receives a pressure of a predetermined value or more from the downstream side, the backflow prevention main body member displaces to the upstream side to open the opening of the flow path, A composite valve characterized in that it is configured to allow a flow path to bypass the flow path to be formed. The composite valve according to claim 2,
The valve body of the backflow prevention unit receives a pressing force from the forward direction of the fluid and moves in a direction to open the fluid passage of the backflow prevention body member, and receives the pressing force from the reverse direction of the fluid to receive the backflow prevention body. A composite valve which is returned to a position where a fluid passage of a member is closed. A composite valve according to claim 2 or claim 3,
A composite valve characterized in that the flow path bypassing the backflow prevention portion is closed by pressing the sealing surface of the backflow prevention main body member against the opening edge of the flow path by elastic force. A composite valve according to any one of claims 2 to 4,
The valve body of the backflow prevention part is a sphere, the backflow prevention body member is formed in a disc shape, and a fluid passage is formed in the center of the backflow prevention body member. An engine blow-by gas reduction device comprising the composite valve according to claim 1,
A blow-by gas reduction passage communicating the throttle valve downstream side of the intake pipe for supplying combustion air to the engine and the crank chamber of the engine;
An air introduction passage communicating the throttle valve upstream side of the intake pipe and the crank chamber;
The blow-by gas reduction device for an engine, wherein the composite valve is attached to the air introduction passage so that an intake pipe side of the engine is an upstream side.

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