JPH0653869U - Check valve - Google Patents

Abstract

(57) [Abstract] [Purpose] Impact noise generated when a check valve, which accommodates a valve seat fitted with a lip valve and a coil spring, is opened and a damper material is placed inside the coil spring to cushion the movement. To decrease. [Structure] A valve seat 2 into which a lip valve 3 is fitted is housed inside a valve case 1 having inlets and outlets 6 and 7. The valve seat 2 has a bottomed tubular shape, a support plate 2c is provided horizontally, and an opening is formed in the bottom wall. The lip valve 3 has an annular shape.
The coil spring 4 is contracted between the valve case 1 and the valve seat 2, and the lip valve 3 closes the inlet 6 of the valve case 1. An elastic damper body 5 is arranged in contact with the inside of the coil spring 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a check valve incorporated in a fuel system of an internal combustion engine to control the internal pressure of a fuel tank.

[0002]

[Prior art]

 In a fuel tank of an internal combustion engine, the stored fuel evaporates inside or the fuel is sucked out during engine operation, causing the internal pressure to constantly fluctuate between pressurized and depressurized states, and the vaporized fuel vapor is released into the atmosphere. The fuel flow to the engine or to the engine is uneven. Therefore, the check valve shown in FIG. 2 is provided in connection with the fuel tank, and the carbon canister is provided in connection with the check valve.

The check valve of FIG. 2 accommodates a valve seat 2 having a lip valve 3 and an umbrella valve 8 mounted in a tubular valve case 1 having an inlet 6 and an outlet 7 on one side and the other side, respectively. The coil spring 4 is contracted between the valve seat 2 and the valve case 1. The valve case 1 is made of synthetic resin, and comprises a cup-shaped body 1b having an outlet 7 in the center of the bottom wall and a cover 1a having a thin disk shape and an inlet 6 in the center thereof. The body 1b has an open end. The cover 1a is fixed to the. The valve seat 2 is composed of an upper seat 2a and a lower seat 2b made of synthetic resin. The upper seat 2a has a bottomed cylindrical shape with an opening at the center of the bottom wall, and the lower seat 2b has a cylindrical shape and has an inner circumference. A support plate 2c having a holding hole for the umbrella-shaped valve 8 in the central portion and a plurality of through holes formed around the hole is integrally formed at approximately the center of the side wall, and the inner peripheral side wall of the upper seat 2a is formed. It is tightly fitted to. The lip valve 3 is an annular member made of an elastic material such as a rubber material. An annular flange portion and an annular recessed groove portion continuous with the flange portion are formed at substantially the center of the outer peripheral side wall. A lip portion 3a having a gradually thinned tip is formed on the portion, and a communication hole is formed on the inner side. The lip valve 3 is fixed by fitting a groove into the opening of the valve seat 2 with the lip 3a outside. Further, on the valve seat 2, the umbrella-shaped valve 8 is fixed to the support plate 2c by inserting the umbrella-shaped valve 8 inwardly into the holding hole. The valve seat 2 in which the lip valve 3 and the umbrella-shaped valve 8 are assembled is a valve seat in which the coil spring 4 is contracted between the support plate 2c and the bottom wall of the body 1b using the inner periphery of the side wall of the lower seat 2b as a guide. It is mounted in the case 1, and the lip portion 3a of the lip valve 3 is pressed against the inner wall of the cover 1a to close the inlet 6. The check valve is used by connecting the inlet 6 with a fuel tank (not shown) through a communication pipe and the outlet 7 with a carbon canister (not shown) through a communication pipe.

This check valve is used when the pressure in the fuel tank rises, for example, when the fuel tank is warmed and the internal fuel evaporates and the internal pressure rises, for example, when the vehicle on which the internal combustion engine is mounted is parked under the scorching sun. The pressure of the fuel vapor is also transmitted to the inlet 6 of the check valve connected to the fuel tank. The pressure of this steam is transmitted from the communication hole of the lip valve 3 to the space defined by the upper seat 2a and the lower seat 2b, overcoming the elastic force of the coil spring 4 to push down the valve seat 2, and the cover 1a. And the lip portion 3a of the lip valve 3 are separated from each other to open the check valve. The steam flowing into the valve case 1 flows down in the case 1 toward the outlet 7, flows from the outlet 7 to the carbon caster, and the internal pressure of the fuel tank is restored to normal pressure.

[0005]

[Problems to be solved by the device]

 By the way, in the above check valve, in order to prevent the steam from the inlet from directly flowing to the lip of the lip valve and pushing the lip open when the valve is opened, the steam introduced from the inlet is introduced into the valve seat. It is once drawn in and led to the lip part again, but when the valve is opened, the steam that has entered the space inside the valve seat and the steam that has entered from the inlet merge at the lip part to form a turbulent flow and form a cover. Flowing through the gap. Due to this turbulent flow, the steam pressure constantly changes near the inlet, and the force that presses the valve seat due to the steam flow and the elastic force of the coil spring that biases the valve seat toward the cover side against this pressing force. Are balanced and become unstable, and the valve seat vibrates in the valve case, resulting in a striking sound that strikes the lip valve fixed to the valve seat and the inner wall of the cover.

[0006]

[Means for Solving the Problems]

 According to the present invention, a tubular valve case having an inlet and an outlet has a bottomed tubular shape, a support plate is provided laterally on the inner periphery of a side wall, and an opening is provided in the bottom wall to fit an annular lip valve into the opening. In a check valve in which a valve seat is housed and a coil spring is compressed between the valve seat and the valve case to close the inlet with a lip valve, a columnar damper body with elasticity that is inscribed in the coil spring is installed. It regulates unnecessary movement of the valve seat.

[0007]

[Action]

 As the internal pressure of the fuel tank rises, the vapor pressure is transmitted to the valve seat and the check valve is pushed down. At this time, turbulence occurs in the steam flow near the inlet and the lip of the lip valve, and the steam pressure constantly fluctuates, and the steam pressure also fluctuates due to the steam flowing into the check valve. Due to both of these pressure fluctuations, the coil spring expands and contracts in the check valve so that the steam pressure pressing the valve seat and the elastic force of the coil spring are balanced, and the valve seat vibrates.

However, since the damper body is arranged so as to be inscribed in the coil spring, the coil panel expands and contracts, but is in contact with the damper body, and the vibration frequency decreases due to the frictional force with the damper body. Further, since the damper body also has elasticity, it expands and contracts with the coil spring, and the amplitude of vibration is reduced. Vibration is suppressed by these and the impact sound is reduced.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to FIG. The check valve of the present invention has the same basic structure as the conventional check valve shown in FIG. Therefore, in FIG. 1, the same configurations as those in FIG.

The check valve shown in FIG. 1 includes a valve case 1, a valve seat 2, a lip valve 3, an umbrella valve 8, a coil spring 4 and a damper body 5, and a lip valve 3 and an umbrella valve are provided in a valve case 1. The coil spring 4 is housed in the valve seat 2 to which the valve 8 is attached, the coil spring 4 is contracted between the valve seat 2 and the valve case 1, and the damper body 5 is arranged inside the coil spring 4. The valve case 1 is made of synthetic resin such as polyamide and comprises a cup-shaped body 1b and a thin disk-shaped cover 1a. The body 1b is integrally provided with a pipe-shaped outlet 7 in the center of the bottom wall so that the outlet 7 lies sideways. The outlet 7 communicates with the inside of the body 1b. The cover 1a is integrally provided with a pipe-shaped inlet 6 in the center thereof, and the outer peripheral edge is fitted and fixed to the open end of the body 1b. The inlet 1a and the outlet 1b communicate with each other via the valve case 1.

The valve seat 2 includes an upper seat 2a and a lower seat 2b made of synthetic resin such as polyacetal. The upper sheet 2a has a cylindrical shape with a bottom and an opening is provided at the center of the bottom wall, and the lower sheet 2b has a cylindrical shape, and a holding hole is provided at the center of the inner peripheral side wall and the holding hole is centered. The support plate 2c having a plurality of through holes is integrally provided on the circumference. The lower sheet 2b is airtightly fitted to the inner peripheral side wall of the upper sheet 2a. The lip valve 3 is an annular one made of a rubber material, and is formed by extending an annular brim portion substantially at the center of the outer peripheral side wall and further forming an annular concave groove portion continuous with the collar portion. A lip portion 3a is formed at the end portion so as to gradually become thinner toward the tip, and a communication hole is formed inside. The lip valve 3 is fixed by fitting a concave groove portion into the opening peripheral edge of the valve sheet 2 with the lip portion 3a outside. On the valve seat 2, the umbrella-shaped valve 8 is further fixed to the support plate 2c by inserting the neck portion into the holding hole with the umbrella portion facing the opening. The valve seat 2 in which the lip valve 3 and the umbrella-shaped valve 8 are assembled has a coil spring 4 in the valve case 1 between the support plate 2c and the bottom wall of the body 1b using the inner circumference of the side wall of the lower seat 2b as a guide. It is arranged in a contracted state. The valve seat 2 is pressed by the coil spring 4, and the lip portion 3a of the lip valve 3 is pressed against the inner wall of the cover 1a to close the inlet 6. Inside the coil spring 4, a columnar damper material 5 that is inscribed in the coil spring 4 and is shorter than the free length of the coil spring 4 is disposed. As the damper material 5, a rubber material or a urethane foam material having air permeability and elasticity, for example, including continuous air bubbles inside is used. In the above embodiment, the valve seat 2 in which the umbrella-shaped valve 8 is attached to the support plate 2c of the lower seat 2b and the opening is closed is shown, but the support plate of the lower seat is not provided with an opening or an umbrella-shaped valve. The plate may be a flat plate-shaped blind plate. Similar to the conventional check valves, these check valves are used by connecting the inlet 6 to the fuel tank through a communication pipe such as a rubber hose and connecting the outlet 7 to a carbon canister through a communication pipe.

The pressure of the fuel vapor is transmitted from the inlet 6 of the check valve through the lip valve 3 into the valve sheet 2, and the valve seat 2 is pushed down against the pressing force of the coil spring 4, and the lip portion 3a of the lip valve is pushed. And the cover 1a are separated, and the check valve is opened. At this time, in the vicinity of the inlet 6 and the lip portion 3a, the steam flow from the inlet 6 side directly to the gap between the lip portion 3a and the cover 1a and the steam flowing into the valve seat 2 are supported by the support plate 2c. It collides with the flow again toward the inlet 6 side, and a turbulent flow occurs and the vapor pressure fluctuates. Next, the steam flows into the valve case 1 having a low pressure. The vapor pressure also fluctuates due to this vapor flow. The valve seat 2 moves and vibrates so that the vapor pressure that presses the valve seat 2 and the force of the coil spring 4 that biases the valve seat 2 toward the cover side are balanced.

However, the damper body 5 in contact with the coil spring 4 rubs against the expansion and contraction of the coil spring 4 and delays its movement, thereby reducing the frequency. Further, the damper body 5 is pressed by the valve seat 2 and a part of the outer peripheral surface of the coil spring 4 bulges between the windings and is pressed from above by the windings, or is narrowed between the windings and extended together with the coil spring 4. In combination with the elastic force of the coil spring 4, the coil spring 4 resists the pressing force of the steam and reduces the amplitude of vibration. Therefore, the vibrations are suppressed by these reaction forces, and the impact sound is reduced.

In the check valve provided with the umbrella-shaped valve 8, when the internal pressure of the fuel tank falls below the normal pressure, a negative pressure is transmitted to the valve seat 2 and the umbrella portion of the umbrella-shaped valve 8 is lifted. Negative pressure is transmitted to the case 1, and the air sucked from the carbon canister is sucked from the outlet 7 and flown into the inlet 6 side. Although the damper body 5 is arranged close to the support plate 2c of the valve seat 2, it has air permeability and does not cause a flow injury.

[0015]

[Effect of device]

 As described above, according to the present invention, the support plate is provided laterally on the inner circumference of the peripheral wall, and the annular lip valve is fitted into the opening of the bottomed cylindrical valve seat having the opening on the bottom wall. It is housed in a tubular valve case with a coil spring, the coil spring is contracted between the valve seat and valve case, and the inlet is closed by a lip valve. Since the damper body with elasticity is installed, the coil spring and the outer peripheral surface of the damper body rub against the vibration of the valve seat to serve as a cushioning material to reduce the number of times of expansion and contraction of the coil spring, and also the cylindrical damper body. It expands and contracts in the axial direction and receives the vibration of the valve seat together with the coil spring, and reduces the amplitude of the vibration, reducing the impact noise that occurs when the valve case and the lip valve collide.

[Brief description of drawings]

FIG. 1 is a sectional view of a check valve of the present invention.

FIG. 2 is a sectional view of a conventional check valve.

[Explanation of symbols]

 1 valve case 2 valve seat 2c support plate 3 lip valve 4 coil spring 5 damper body

Claims (1)

[Scope of utility model registration request] 1. A tubular valve case provided with an inlet and an outlet, having a bottomed tubular shape, a support plate provided laterally on an inner periphery of a side wall, and an opening provided in the bottom wall, and an annular lip valve fitted in the opening. In a check valve that accommodates a valve seat to be attached and a coil spring is contracted between the valve seat and the valve case and the inlet is closed by a lip valve, an elastic cylindrical damper body is inscribed in the coil spring. Check valve installed.