Check valve

Abstract

To provide a check valve that maintains smooth opening and closing of the valve body even when condensed water is drawn in, and that can operate stably. [Solution] The check valve 1A comprises a valve body 10 that defines an air passage inside, a valve element 40 disposed inside the valve body 10 and opening and closing the intake port 11 of the air passage, a cap 20 attached to the valve body 10 downstream of the valve element 40 in the air flow direction and having a plurality of through holes 20a formed therein for air to flow through, and a spring 30 provided between the valve element 40 and the cap 20 and biasing the valve element 40 upstream in the air flow direction relative to the valve body 10. The valve element 40 has a conical shape that protrudes upstream from the seal portion S which is the contact portion between the valve body 10 and the valve element 40, and has a plurality of grooves 401 that extend radially downstream from its apex 40t.

Description

Technical Field

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

Background Art

[0002] Conventionally, technologies related to check valves are known. For example, Patent Document 1 describes an EGR valve in which a valve body that communicates or blocks an EGR pipe is housed in a valve case (valve body) provided in the EGR pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Depending on the use environment, a check valve may suck water condensed from the air together with the air. If this condensed water adheres to the contact portion between the valve body and the valve body after staying on the valve body, colliding with the valve body and scattering, and then freezing, the valve body may be difficult to open.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide a check valve that can maintain smooth opening and closing of the valve body and operate stably even in an environment where condensed water can be sucked.

Means for Solving the Problems

[0006] To achieve the above objective, the check valve of the present invention comprises a valve body that defines an air passage inside, a valve element disposed within the valve body and opening and closing an intake port of the air passage, a cap attached to the valve body downstream of the valve element in the air flow direction and having a plurality of through holes formed therein for air to flow through, and an elastic body provided between the valve element and the cap and biasing the valve element upstream of the valve body in the air flow direction, wherein the valve element has a conical shape that protrudes upstream of the seal portion which is the contact portion between the valve body and the valve element, and has a plurality of grooves that extend radially downstream from its apex. [Effects of the Invention]

[0007] According to the check valve of the present invention, it is possible to maintain smooth opening and closing of the valve body even in environments where condensed water can be drawn in, and to operate the check valve stably. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing a brake booster system to which the check valve of the first embodiment is applied. [Figure 2] This is a cross-sectional view showing the closed state of the check valve in the comparative example. [Figure 3] This is a cross-sectional view showing the open state of the check valve in the comparative example. [Figure 4] This is a cross-sectional view showing the closed state of the check valve in the first embodiment. [Figure 5] This is a cross-sectional view showing the open state of the check valve in the first embodiment. [Figure 6] This is a perspective view showing the valve body of the first embodiment. [Figure 7] This is a cross-sectional view showing the closed state of the check valve in the second embodiment. [Figure 8] This is a cross-sectional view showing the state in which the scattering prevention member of the second embodiment has moved. [Figure 9] This is a cross-sectional view showing the closed state of the check valve in the third embodiment. [Figure 10] This is a cross-sectional view showing the state in which the scattering prevention member of the third embodiment has moved. [Modes for carrying out the invention]

[0009] An embodiment of the present invention will be described below with reference to the drawings.

[0010] [First Embodiment] Figure 1 is a schematic diagram showing a brake booster system 100 to which the check valve 1A of the first embodiment is applied. The brake booster system 100 is mounted on a vehicle and uses the power of a camshaft (not shown) of a diesel engine 3 to rotate a vacuum pump 4, and the intake negative pressure from the vacuum pump 4 acts on the brake booster 5. The brake booster 5 assists the force applied to the vehicle's brake pedal by the pressure difference between the intake negative pressure and atmospheric pressure.

[0011] A check valve 1A is positioned between the vacuum pump 4 and the brake booster 5. The check valve 1A is attached to the vacuum pump 4, for example. The check valve 1A includes a valve body 40 that opens and closes the intake port 11 (Figures 4 and 5) of the airflow passage defined in the valve body 10 (Figures 4 and 5) according to the operating state of the vacuum pump 4. When the check valve 1A is in the open state, with the intake port 11 open by the valve body 40, it allows air to flow from the brake booster 5 to the vacuum pump 4, and when the check valve 1A is in the closed state, with the intake port 11 closed by the valve body 40, it blocks the airflow.

[0012] In the piping 6 connecting the check valve 1A and the brake booster 5, condensed water W (Figures 2 and 3) may accumulate due to the high temperature and humidity air supplied from the brake booster 5. This condensed water W is then drawn into the check valve 1A along with the air by the intake negative pressure of the vacuum pump 4. In addition, in the brake booster system 100, liquids such as oil 60 (Figure 2) used to lubricate the camshaft of the diesel engine 3 may be sprayed from the downstream side of the check valve 1A via the vacuum pump 4.

[0013] Figure 2 is a cross-sectional view showing the closed state of the comparative example check valve 1B. Figure 3 is a cross-sectional view showing the open state of the comparative example check valve 1B. The comparative example check valve 1B comprises a valve body 210 having an intake port 211 and defining an air passage, a cap 220 having a plurality of through holes 220a formed therein for air to flow through, a spring 230 attached to the cap 220, and a valve body 240 that is biased against the valve body 210 by the spring 230 and opens and closes the intake port 211. The valve body 240 is a cylindrical member, and its upstream surface in the air flow direction extends radially (it has a surface perpendicular to the air flow direction). The valve body 210 and the valve body 240 are sealed together by contact with each other at a sealing portion S200 that extends radially.

[0014] In such a check valve 1B, as shown by the white arrow in Fig. 3, the condensed water W sucked together with air collides with the upstream surface of the valve body 240 and scatters around. At this time, since the upstream surface of the valve body 240 is flat, the condensed water W tends to accumulate. Further, when the condensed water W scatters near the corner 210a of the valve body 210 where an air vortex is likely to occur, the condensed water W may stay within the vortex region. Furthermore, the oil 60 scattered from the downstream adheres to the plurality of through holes 220a of the cap 220, making it difficult for air and condensed water W to escape. As a result, the condensed water W accumulated near the upstream surface of the valve body 240 and near the corner 210a of the valve body 210 may not be sufficiently discharged. As a result, as shown in Fig. 2, after the check valve 1B is closed, condensed water W remains on the upstream surface of the valve body 240, and the freezing of this condensed water W may occur in this state, making it difficult for the valve body 240 to open. Therefore, the check valve 1A has the following configuration in order to maintain the smooth opening and closing operation of the valve body 40.

[0015] (Check valve) Fig. 4 is a cross-sectional view showing the closed state of the check valve 1A of the first embodiment. Fig. 5 is a cross-sectional view showing the open state of the check valve 1A of the first embodiment. Fig. 6 is a perspective view showing the valve body 40 of the first embodiment. The check valve 1A includes a cylindrical valve body 10, a cap 20, a spring (elastic body) 30, a valve body 40, and a scattering prevention member 50. In the following description, the upstream side (the upper side in Fig. 4) in the air flow direction from the brake booster 5 side to the vacuum pump 4 side is referred to as the "upstream side", and the downstream side (the lower side in Fig. 4) in the air flow direction is referred to as the "downstream side". The air flow direction is the axial direction of the valve body 10. It is assumed that the upstream side is located on the upper side in the vertical direction and the downstream side is located on the lower side in the vertical direction. Also, the radial direction of each component of the check valve 1A is uniformly referred to as the "radial direction".

[0016] (Valve body) The valve body 10 is a hollow casing that defines an air flow passage inside. The valve body 10 has an air intake 11 and a housing portion 12. The air intake 11 is a cylindrical portion connected to a pipe 6 (FIG. 1) extending from the brake booster 5. The air intake 11 forms part of the air flow passage. The housing portion 12 is a portion that houses the other components of the check valve 1A and is formed with a larger diameter than the air intake 11. The housing portion 12 has a first housing portion 121, a second housing portion 122, and a third housing portion 123.

[0017] The first housing portion 121 extends radially outward as it curves to form a bowl shape and extends downstream from the air intake 11. The second housing portion 122 extends radially outward as it goes downstream from the first housing portion 121. The third housing portion 123 extends from the second housing portion 122 downstream with the same diameter as the lower end of the second housing portion 122 and is connected to the vacuum pump 4. The corner portion that is the boundary between the air intake 11 and the first housing portion 121 forms a first valve seat 14 where the valve body 40 seats (contacts). Also, the inner peripheral surface of the second housing portion 122 forms a second valve seat 15 where the valve body 40 seats (contacts). The second valve seat 15 is formed as a flat surface.

[0018] (Cap) The cap 20 is a disk-shaped member attached to the valve body 10 so as to block the air flow passage downstream of the valve body 40. The cap 20 abuts against the inner peripheral surface of the valve body 10 at its outer peripheral edge. However, a plurality of through holes 20a penetrating from the upstream surface to the downstream surface are formed in the cap 20, and air and condensed water W (FIG. 5) are configured to be able to flow through each through hole 20a. Also, a shaft insertion hole 20b penetrating from the upstream surface to the downstream surface is formed at the radially central portion of the cap 20. A shaft 51 of a splash prevention member 50 described later is inserted into the shaft insertion hole 20b. Note that a disk-shaped protrusion 22 into which the spring 30 is fitted is formed on the upstream surface of the cap 20.

[0019] (Spring) The spring 30 is a coil spring interposed between the cap 20 and the valve body 40. The spring 30 is attached at one end to the upstream surface of the cap 20 and at the other end to the downstream surface of the valve body 40 so that it can expand and contract along the direction of airflow within the valve body 10. The spring 30 biases the valve body 40 upstream, that is, toward the first valve seat 14 and the second valve seat 15 of the valve body 10.

[0020] (valve body) The valve body 40 is a component that opens and closes the intake port 11 inside the valve body 10. The valve body 40 is supported by the cap 20 via a spring 30 and is swingable relative to the valve body 10 in the direction of airflow. The valve body 40 has a conical shape, and as shown in Figure 4, when seated on the first valve seat 14 and the second valve seat 15 of the valve body 10, its apex 40t protrudes upstream of the first valve seat 14.

[0021] The valve body 40 has a first inclined portion 41, a second inclined portion 42, and a third inclined portion 43. The first inclined portion 41 extends radially outward from the apex 40t toward the downstream side. As shown in Figure 4, a portion of the first inclined portion 41 has a part that seats on the first valve seat 14 of the valve body 10. The contact portion between the first inclined portion 41 and the first valve seat 14 forms a first seal portion S1 that seals the space between the valve body 10 and the valve body 40. The first inclined portion 41 is formed such that the inclination angle becomes gentler toward the downstream side from the seating portion 41a (Figure 6) that contacts the first valve seat 14. In addition, the first inclined portion 41 has a plurality of grooves 401 that extend radially from the apex 40t at intervals from each other in the circumferential direction. Each groove 401 is provided to converge at the apex 40t. Furthermore, each groove 401 is provided within the range upstream of the first seal portion S1 (towards the apex 40t).

[0022] The second inclined portion 42 extends further radially outward as it is directed downstream from the first inclined portion 41. The second inclined portion 42 is more gently inclined than the first inclined portion 41. As shown in Figure 6, an annular groove 402 is formed in the second inclined portion 42, which is recessed toward the downstream side. The annular groove 402 extends around the entire circumference of the second inclined portion 42. The annular groove 402 is provided to suppress the rapid and large influx of condensed water W, described later, into the vicinity of the contact area between the valve body 10 and the valve element 40, which forms the second seal portion S2. Therefore, the annular groove 402 is positioned not too far from the second seal portion S2 so that condensed water W can be sufficiently captured upstream of the second seal portion S2. The annular groove 402 may be formed only on a part of the circumferential direction, within a range that allows sufficient capture of condensed water W.

[0023] The third inclined portion 43 extends further radially outward as it moves downstream from the second inclined portion 42. A disc-shaped projection 44 into which the spring 30 is fitted is formed on the downstream surface of the valve body 40. The third inclined portion 43 is steeper inclined than the second inclined portion 42. As shown in Figure 4, the third inclined portion 43 is the part that seats on the second valve seat 15 of the valve body 10. The contact portion between the third inclined portion 43 and the second valve seat 15 becomes a second seal portion S2 that seals the space between the valve body 10 and the valve body 40.

[0024] Thus, the check valve 1A is provided with multiple sealing portions S that seal the space between the valve body 10 and the valve element 40. Of the sealing portions S, the first sealing portion S1 is a contact portion at a corner formed on the valve body 10, while the second sealing portion S2 is a planar contact portion. Therefore, the contact area between the valve body 10 and the valve element 40 is smaller for the first sealing portion S1 compared to the second sealing portion S2.

[0025] (Scatter prevention material) The splash prevention member 50 has a shaft 51 and a splash prevention plate (suction member) 52. The shaft 51 is attached to the valve body 40 and extends downstream along the air flow direction, passing inside the spring 30. The shaft 51 is movably inserted through a shaft insertion hole 20b formed in the cap 20 and protrudes downstream of the cap 20. The splash prevention plate 52 is a plate-shaped member attached to the downstream end of the shaft 51 opposite to the valve body 40. The splash prevention plate 52 extends downstream as it moves radially outward from the shaft 51. That is, the splash prevention plate 52 has an umbrella shape. The splash prevention plate 52 is positioned so as to overlap with a plurality of through holes 20a formed in the cap 20 when viewed from the air flow direction. A gap is provided between the splash prevention plate 52 and the inner circumferential surface of the valve body 10 for the flow of air and condensed water W.

[0026] (Check valve operation) The operation of the check valve 1A, configured as described above, will now be explained. When the vacuum pump 4 is not operating, as shown in Figure 4, the spring 30 biases the valve body 40 upstream relative to the valve body 10, causing the first inclined portion 41 to seat on the first valve seat 14 and the third inclined portion 43 to seat on the second valve seat 15. As a result, the space between the valve body 10 and the valve body 40 is sealed, and the intake port 11 is blocked, thereby cutting off communication between the vacuum pump 4 and the brake booster 5.

[0027] On the other hand, when the vacuum pump 4 is operating, as shown in Figure 5, the intake negative pressure from the vacuum pump 4 pulls the valve body 40 and the splash guard plate 52 downstream, causing the valve body 40 to move downstream. At this time, the shaft 51 moves together with the valve body 40, and the splash guard plate 52 also moves downstream, so that the airflow from the multiple through holes 20a is not obstructed by the splash guard member 50. As a result, contact between the valve body 40 and the first valve seat 14 and the second valve seat 15 is released, the intake port 11 opens, and the vacuum pump 4 and the brake booster 5 are connected.

[0028] At this time, as described above, condensed water W (Figure 5) may be drawn into the check valve 1A along with air from inside the piping 6. In contrast, the valve body 40 of the check valve 1A in the first embodiment has a conical shape (conical shape) that protrudes upstream from the seal portion S (first seal portion S1), which is the contact portion between the valve body 10 and the valve body 40, and has a plurality of grooves 401 that extend radially downstream from its apex 40t.

[0029] With this configuration, even if condensed water W collides with the apex 40t of the valve body 40, the condensed water is smoothly guided downstream along the inclined surface from the apex 40t, as shown by the white arrow in Figure 5. Furthermore, the condensed water W can be guided more smoothly along the multiple radially formed grooves 401. Subsequently, the condensed water W flows towards the cap 20 through the gap between the valve body 40 and the inner circumferential surface of the valve body 10, and is discharged from the check valve 1A through the multiple through holes 20a. This prevents the condensed water W from accumulating on the valve body 40 or at the corners of the valve body 10, and suppresses the occurrence of freezing of the seal portion S. Therefore, even in environments where condensed water W can be drawn in, it is possible to maintain smooth opening and closing of the valve body 40 and to operate the check valve 1A stably.

[0030] Furthermore, the valve body 10 has a housing section 12 (first housing section 121 and second housing section 122) that accommodates the valve element 40, and the housing section 12 widens radially outward as it moves downstream from the intake port 11 in the direction of air flow. With this configuration, even if condensed water W is scattered and adheres to the inner circumferential surface of the housing section 12, as shown by the arc-shaped arrow in Figure 5, the condensed water W is smoothly guided downstream along the inclined inner circumferential surface, and its accumulation can be suppressed more effectively. Note that the housing section 12 may also have a shape that widens flatly radially outward from the intake port 11, similar to the check valve 1B of the comparative example.

[0031] Furthermore, multiple sealing portions S are provided between the valve body 10 and the valve element 40. This configuration ensures airtightness across the entire sealing portion S while reducing the contact area of ​​each individual sealing portion S compared to a configuration with only one sealing portion S. As a result, even if condensate W freezes at any of the sealing portions S, the force pulling the valve element 40 downstream makes it easier to remove the frozen portion.

[0032] Furthermore, the seal portion S includes a first seal portion S1 and a second seal portion S2 located downstream of the first seal portion S1 in the airflow direction. The contact area between the valve body 10 and the valve element 40 in the first seal portion S1 is set to be smaller than the contact area in the second seal portion S2. In this way, by making the first seal portion S1, which is located further upstream and is therefore more likely to accumulate condensate W and thus more likely to freeze, smaller than the second seal portion S2, even if freezing occurs in the first seal portion S1, the force pulling the valve element 40 downstream makes it easier to remove the frozen portion. Note that only one seal portion S may be provided in the check valve 1A as long as airtightness can be ensured. Also, three or more seal portions S may be provided as long as ease of removal in the event of freezing can be ensured.

[0033] Furthermore, the valve body 40 has an annular groove 402 extending circumferentially between the first seal portion S1 and the second seal portion S2. With this configuration, as shown by the white arrow in Figure 5, a portion of the condensed water W flowing along the upstream surface of the valve body 40 can be captured by the annular groove 402. As a result, it is possible to suppress the influx and accumulation of a large amount of condensed water W in a short time near the contact portion between the valve body 10 forming the second seal portion S2 and the valve body 40, thereby suppressing the occurrence of freezing in the second seal portion S2. At least a portion of the condensed water W captured by the annular groove 402 flows downstream when the valve body 40 opens. Note that the annular groove 402 may be omitted from the valve body 40.

[0034] Furthermore, the multiple grooves 401 are provided upstream of the seal portion S (first seal portion S1) in the airflow direction. This configuration prevents the sealing of the seal portion S (first seal portion S1) from being obstructed by the multiple grooves 401. However, it is preferable that the multiple grooves 401 extend to a position close to the first seal portion S1 so that the condensed water W can be guided downstream as smoothly as possible.

[0035] Furthermore, as described above, oil 60 that lubricates the camshaft of the diesel engine 3 may be scattered from the downstream side of the check valve 1A. In response to this, the check valve 1A of the first embodiment is equipped with a splash prevention plate 52 that is positioned downstream of the cap 20 in the airflow direction and overlaps with a plurality of through holes 20a when viewed from the airflow direction.

[0036] With this configuration, as shown in Figures 4 and 5, the splash-proof plate 52 catches the oil 60 splashing from the downstream side of the check valve 1A, suppressing the adhesion of the oil 60 to the multiple through holes 20a formed in the cap 20. As a result, the flow of air and condensed water W in the multiple through holes 20a can be maintained in good condition. Therefore, even in environments where liquids such as oil 60 are splashed from the downstream side, the smooth opening and closing of the valve body 40 can be maintained, and the check valve 1A can be operated stably.

[0037] Furthermore, the splash guard plate 52 extends downstream in the airflow direction as it moves radially outward. In this way, the umbrella shape of the splash guard plate 52 can more effectively suppress the oil 60 splashing from the downstream side toward the cap 20 side. In addition, condensed water W flowing from the upstream side is less likely to accumulate on the splash guard plate 52. Moreover, air can easily escape downstream around the splash guard plate 52, which suppresses the splash guard plate 52 from becoming a resistance to the operation of the valve body 40 due to intake negative pressure.

[0038] Furthermore, the check valve 1A is further equipped with a shaft 51 extending downstream from the valve body 40 along the airflow direction, and the cap 20 has a shaft insertion hole 20b through which the shaft 51 is inserted, and the splash guard 52 is attached to the end of the shaft 51 opposite to the valve body 40. With this configuration, the splash guard 52 moves together with the valve body 40 connected by the shaft 51. Therefore, as shown in Figure 4, when the valve body 40 is in the closed state, the splash guard 52 is positioned close to the cap 20, thereby more reliably suppressing the adhesion of oil 60 to the multiple through holes 20a. On the other hand, as shown in Figure 5, when the valve body 40 is in the open state, the splash guard 52 is sufficiently far from the cap 20, so that the airflow is not obstructed and the splash guard 52 does not become a resistance. Note that the splash guard 50 does not have to move together with the valve body 40, and may be directly attached to the valve body 10, for example, as long as it does not obstruct the flow of air or condensed water W.

[0039] [Second Embodiment] Figure 7 is a cross-sectional view showing the closed state of the check valve in the second embodiment. Figure 8 is a cross-sectional view showing the state in which the splash prevention member in the second embodiment has moved. The check valve 1C in the second embodiment is equipped with a splash prevention member 50C instead of the splash prevention member 50 in the first embodiment.

[0040] The scattering prevention member 50C includes a shaft 51C, a scattering prevention plate (attracted member) 52C, a spring receiving portion 53C, and a spring (second elastic body) 54C. The shaft 51C extends downstream from the valve body 40, as in the first embodiment, and is inserted through the shaft insertion hole 20b of the cap 20. The shaft 51C is also inserted through the scattering prevention plate 52C and protrudes downstream of the scattering prevention plate 52C. The spring receiving portion 53C is attached to the downstream end of the shaft 51C. The spring 54C biases the scattering prevention plate 52C toward the valve body 40. Specifically, one end of the spring 54C is attached to the upstream surface of the spring receiving portion 53C, and the other end is attached to the downstream surface of the scattering prevention plate 52C. The elastic modulus of spring 54C is set to a size that allows it to be compressed by the intake negative pressure acting on the anti-scattering plate 52C.

[0041] The shatterproof plate 52C is a disc-shaped member that is arranged to overlap with the multiple through holes 20a of the cap 20 along the direction of airflow. The shatterproof plate 52C is supported by a spring receiving portion 53C via a spring 54C. A shaft insertion hole 52b is formed in the radial center of the shatterproof plate 52C through which the shaft 51C is inserted. A flange portion 52f is also formed on the edge of the shatterproof plate 52C, into which the spring 54C is fitted.

[0042] As shown in Figure 7, when the vacuum pump 4 is not operating, the splash guard plate 52C is biased upstream by the spring 54C and is supported to swing freely downstream of the cap 20. When the vacuum pump 4 is activated from this state and the intake negative pressure acting on the splash guard plate 52C exceeds the biasing force of the spring 54C, the splash guard plate 52C moves downstream, as shown in Figure 8. Compared to when the spring 54C is not present, the splash guard plate 52C can be separated from the cap 20C, and the resistance caused by the splash guard plate 52C can be suppressed more effectively. Also, when the valve body 40 moves downstream against the biasing force of the spring 30 due to the action of the intake negative pressure, the intake port 11 opens.

[0043] Here, let's assume that freezing occurs in at least one of the first seal portion S1 and the second seal portion S2, and the valve body 40 does not move immediately. In this case, as shown in Figure 8, when the spring 54C is fully compressed, the impact caused by the movement of the splash guard plate 52C acts on the spring receiving portion 53C. This impact is transmitted to the valve body 40 via the shaft 51C, and a force acts on the first seal portion S1 and the second seal portion S2 in a direction that peels off the freezing. As a result, the freezing in the first seal portion S1 and the second seal portion S2 can be broken up, making it possible to smoothly open the valve body 40 and stably operate the check valve 1C.

[0044] [Third Embodiment] Figure 9 is a cross-sectional view showing the closed state of the check valve of the third embodiment. Figure 10 is a cross-sectional view showing the state in which the splash prevention member of the third embodiment has moved. The check valve 1D of the third embodiment is equipped with a valve body 40D in place of the valve body 40 of the first embodiment, and a splash prevention member 50D in place of the splash prevention member 50.

[0045] The valve body 40D has an internal space 40a that houses a portion of the components of the splash-proof member 50D. A shaft insertion hole 40b that penetrates the protruding portion 44 of the valve body 40D is connected to the internal space 40a. A communication passage 40c is also connected to the internal space 40a. The communication passage 40c extends from the upstream surface of the valve body 40D, specifically from the portion located between the first seal portion S1 and the second seal portion S2. It is preferable that the communication passage 40c be formed at a position away from the first seal portion S1, that is, close to the second seal portion S2, in order to more reliably maintain airtightness between the valve body 10 and the valve body 40D.

[0046] The scattering prevention member 50D includes a shaft 51D, a scattering prevention plate (attracted member) 52, a spring receiving portion 53D, and a spring (second elastic body) 54D. The shaft 51D extends downstream through the shaft insertion hole 20b of the cap 20, and the scattering prevention plate 52 is attached to its downstream end. On the other hand, the upstream end of the shaft 51D is inserted into the internal space 40a of the valve body 40D via the shaft insertion hole 40b, and the spring receiving portion 53D is attached thereto. One end of the spring 54D is attached to the downstream surface of the internal space 40a of the valve body 40D, and the other end is attached to the downstream surface of the spring receiving portion 53D. As a result, the spring 54D is positioned between the shaft 51D and the valve body 40, and by biasing the spring receiving portion 53D upstream, it biases the scattering prevention plate 52 toward the valve body 40D via the shaft 51D. The elastic modulus of the spring 54D is set to a size that allows it to be compressed by the intake negative pressure acting on the anti-scattering plate 52.

[0047] As shown in Figure 9, when the vacuum pump 4 is not operating, the splash guard plate 52 remains biased upstream by the spring 54D, similar to the second embodiment. When the vacuum pump 4 is activated from this state and the intake negative pressure acting on the splash guard plate 52D exceeds the biasing force of the spring 54D, the shaft 51 and the splash guard plate 52 move downstream, as shown in Figure 10. Also, when the valve body 40D moves downstream against the biasing force of the spring 30 due to the intake negative pressure, the intake port 11 opens.

[0048] Here, we assume that freezing has occurred in at least one of the first seal portion S1 and the second seal portion S2, and the valve body 40D does not move immediately. In this case, as shown in Figure 10, when the spring 54D is fully contracted, the impact caused by the movement of the anti-scattering plate 52 is transmitted to the valve body 40D via the spring 54D, and a force acts on the first seal portion S1 and the second seal portion S2 in a direction that peels off the freezing. As a result, the freezing in the first seal portion S1 and the second seal portion S2 can be broken up, making it possible to smoothly open the valve body 40D and stably operate the check valve 1B.

[0049] Furthermore, as shown in Figure 10, a portion of the condensed water W flows into the internal space 40a of the valve body 40D through the communication passage 40c. When this condensed water W freezes in the internal space 40a, ice forms between the spring support portion 53D and the wall surface of the internal space 40a and between the spring 54D, making it difficult for the spring 54D to undergo elastic deformation. As a result, the force with which the splash guard plate 52 pulls the valve body 40 downstream due to the intake negative pressure is not weakened by the biasing force of the spring 54D. This ensures that a downstream force acts on the valve body 40, making it easier to remove the frozen material from the first seal portion S1 and the second seal portion S2.

[0050] In addition, when the condensate in the internal space 40a is broken up by the force pulling the anti-scattering plate 52 downstream due to the intake negative pressure, the anti-scattering plate 52 moves rapidly downstream, and the impact is transmitted to the frozen areas of the first seal section S1 and the second seal section S2 as described above. In this way, by freezing the area around the spring 54D, the above impact can be effectively generated, making it possible to break up the frozen areas of the first seal section S1 and the second seal section S2. The condensed water W in the internal space 40a is discharged downstream through the gap between the shaft insertion hole 40b and the shaft 51D.

[0051] Furthermore, the configurations of the second embodiment and the third embodiment may be used in combination. That is, in the check valve 1C equipped with the splash prevention member 50C of the second embodiment, the valve body 40 may be replaced with a valve body 40D, a spring receiving portion 53D may be provided at the upstream end of the shaft 51C and placed in the internal space 40a of the valve body 40D, and a spring 54D may be placed between the spring receiving portion 53D and the valve body 40D.

[0052] This concludes the description of the embodiments, but the aspects of the present invention are not limited to these embodiments. For example, in the first to third embodiments, the upstream side in the air flow direction (axial direction) was positioned vertically upward and the downstream side vertically downward, but the orientation of the check valves 1A, 1C, and 1D is not limited to this. The orientation of the check valves 1A, 1C, and 1D may be such that the axial direction is inclined at a predetermined angle with respect to the vertical, within the range in which the effects of each embodiment can be obtained. Furthermore, in the first to third embodiments, the example of the check valves 1A, 1C, and 1D being applied to a brake booster system 100 was described, but the present invention may be applied to systems other than the brake booster system 100. [Explanation of Symbols]

[0053] 1A, 1B, 1C, 1D Check valves 10,210 Valve Body 11, 211 Intake port 12 Storage Unit 121 First Detention Unit 122 Second Detention Unit 123 Third Detention Unit 14. First valve seat 15. Second valve seat 20,220 caps 20a, 220a through hole 20b, 40b, 52b shaft insertion holes 30,230 Spring (Elastic Body) 40, 40D, 240 valve body 40a Interior space 40c communication path 40t peak 41 1st slope part 42 2nd slope part 43 Third slope 401 Groove 402 Annular groove 50, 50C, 50D Shatterproof material 51, 51C, 51D shafts 52, 52C Scattering prevention plate (suctioned member) 52f Flange section 53C, 53D Spring support section 54C, 54D Springs (Second Elastic Body) 60 Oil (liquid) 100 Brake Booster System S, S200 seal section S1 First seal section S2 Second seal section W Condensed water

Claims

1. A valve body that defines an airflow passage inside, A valve body is disposed within the valve body and opens and closes the intake port of the air passage, A cap is attached to the valve body downstream of the valve body in the airflow direction, and has multiple through holes formed therein for air to flow through. An elastic body is provided between the valve body and the cap, and biases the valve body toward the upstream side in the airflow direction relative to the valve body, Equipped with, The valve body has a conical shape that protrudes upstream from the sealing portion which is the contact portion between the valve body and the valve body, and has a plurality of grooves that extend radially downstream from its apex.

2. The valve body has a housing portion for housing the valve element, The aforementioned housing extends radially outward as it moves downstream from the intake port, The check valve according to claim 1.

3. The check valve according to claim 1, wherein a plurality of sealing portions are provided.

4. The sealing portion includes a first sealing portion and a second sealing portion located downstream of the first sealing portion. The contact area between the valve body and the valve element in the first seal portion is set to be smaller than the contact area in the second seal portion. The check valve according to claim 3.

5. The check valve according to claim 4, wherein the valve body has an annular groove extending circumferentially between the first sealing portion and the second sealing portion.

6. The check valve according to claim 1, wherein the plurality of grooves are provided upstream of the sealing portion.

7. A shaft extending downstream from the valve body along the airflow direction, A member to be attracted is provided at the end of the shaft opposite to the valve body, A second elastic body provided between the shaft and the member to be attracted, and between the valve body and the shaft, A check valve according to any one of claims 1 to 6, further comprising:

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