JPH0751990B2 - Negative pressure control valve used for wall traveling device - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a negative pressure adjusting valve used for a wall surface traveling device.

[Prior art]

As a pressure regulating valve for adjusting or maintaining the pressure in the closed space, a pressure valve (pressure reducing valve) for keeping the pressure in the container below a certain value or a pressure for adjusting the pressure in the pressure chamber of the aircraft A well-known device for maintaining high pressure, such as a control valve, is known as a device for maintaining negative pressure.
No. 166572 discloses a negative pressure regulating valve. As shown in FIG. 5, the negative pressure adjusting valve includes a valve rod 21 supported so as to be vertically movable, and a negative pressure chamber 23 having a central portion fixed to the valve rod 21 and having a negative pressure inlet 22. A valve capable of opening and closing a valve seat hole 30 provided in a partition wall 29 fixed to the valve rod 21 and defining upper and lower diaphragms 24 and 25 and partitioning the inlet side 27 and the outlet side 28 of the valve box 26. The body 31 and the negative pressure chamber 23
The valve opening is adjusted by changing the negative pressure inside. This negative pressure regulating valve is used in the exhaust system of a glove box in a nuclear facility. On the other hand, various robots are being developed in order to perform extreme work, that is, work under high heat or radiation that is difficult for humans to approach, or to eliminate the danger of work at heights, and one of them is a wall surface traveling device. The wall surface traveling device travels by a crawler provided separately while adsorbing the device to the wall surface by vacuum adsorption, and the key point of the technique is how to secure the vacuum adsorption. The vacuum suction of the wall surface traveling device makes the box closely adhere to the wall surface,
The inside is evacuated to a negative pressure (low vacuum). However, as the vehicle travels, air leaks from the surrounding normal pressure space to the negative pressure space, and the degree of negative pressure (vacuum degree) may decrease. As a countermeasure, it is possible to first increase the capacity of the vacuum exhaust blower. However, this should be avoided because it makes the wall traveling device heavy, and it is desirable that the blower capacity is minimized and the negative pressure is adjusted skillfully with a certain degree of safety. The above-mentioned pressure valve of the high-pressure container and the pressure control valve used for the aircraft are all for keeping the container and the room at a high pressure or at a certain pressure or less, and a constant negative pressure (low vacuum) is set. It cannot be used for the purpose of keeping the value. Fifth
The negative pressure adjustment valve in the figure shows the pressure fluctuation in the negative pressure chamber 23
The diaphragm 24,25 that defines the
Since it is a mechanism for moving 1 up and down, it can be used only when the vertical movement range of the valve body 31 is small, the structure is relatively complicated and heavy, and the responsiveness is slow. Therefore, this pressure regulating valve is not suitable as a negative pressure regulating valve for a wall surface traveling device, which is required to be lightweight and compact and to respond instantly to large pressure fluctuations.

[Problems to be Solved by the Invention]

In view of the current state of the art as described above, the purpose of the present invention is to
It is suitable for use as a negative pressure control valve in a wall traveling device and can be constructed in a lightweight and small size, and has an excellent function of maintaining a constant negative pressure even in a low negative pressure region, and the valve opens instantly in response to a pressure change. It is to provide a negative pressure regulating valve capable of adjusting the degree.

[Means for Solving the Problems]

The negative pressure regulating valve of the present invention forms a closed space I with a box A on a wall surface W, as shown in FIG. 6, and constantly evacuates the inside thereof while at the same time supplying air through the negative pressure regulating valve. 1 and 2 show a negative pressure adjusting valve V which is directly attached to a wall surface traveling device that travels while adsorbing a box on a wall surface by inflowing and keeping the closed space at a substantially constant negative pressure. As shown, the bottom portion of the case 2 having a bottomed tubular body that divides the surrounding positive pressure space and negative pressure space is opened, and a direction in which the flow of air that is annular and flows into the valve is narrowed to this opening A valve seat member 3 having an inclined taper surface and projecting beyond the opening to form an annular valve seat at the tip of the tapered surface, and extending in the axial direction of the tubular body through the opening. , One end of which is provided with a disc-shaped valve body 4 which contacts the valve seat from the outside, and the other end of which is provided. (4) A valve rod having a receiving member is mounted by a guide post 6 which is axially movable and which itself is fixed to a case and has a bearing 7 inside, and the lower portion of which is located in the opening. Coil spring 9 having a diameter which is located near the inner surface of the case between the inside of the case bottom and the spring receiving member.
Is provided to urge the valve rod in the valve closing direction by a compressive force, and the valve body 4 is brought into direct surface contact with the valve seat to form a valve. As shown in FIG. Air flowing in a flow parallel to the axial direction of the body is narrowed by the tapered surface to form a cylindrical flow, passes through the opening, and hits the disc-shaped valve body 4 to change its direction in the radial direction. The valve is opened while the pressure difference between the upstream (positive pressure) side and the downstream (negative pressure) side of the valve is maintained. Maintains a predetermined pressure difference while allowing a certain amount of air to flow in the state corresponding to the vacuum exhaust amount,
When the pressure rise exceeds 0.01 Bar, the valve body 4 is moved by the force of the coil spring 9 due to the pressure rise on the negative pressure side directly acting on the back of the valve body, and the valve is closed. It is characterized in that a predetermined pressure difference is recovered within 0.5 seconds by removing the pressure difference from. The valve seat is usually held by a case and attached to the partition between the ambient pressure side and the negative pressure side, that is, the box of the wall surface traveling device. Depending on the size of the negative pressure to be maintained, the range of fluctuation, the amount of air to be introduced from this positive pressure side to the negative pressure side through this pressure regulating valve, etc. Design appropriately. Needless to say, the area of the ring-shaped air passage formed in the opening 3 of the valve seat member 1 is selected so that the vacuum exhaust amount can maintain a predetermined negative pressure even when the valve is fully opened. Should.

[Action]

As shown in FIG. 6, the space I on the negative pressure side, which is closed from the surroundings in the wall surface traveling device, is in a negative pressure state because air is continuously discharged from the space I by the blower B. At the same time, the pressure regulating valve V is opened, and a certain amount of air from the positive pressure side of the surroundings, that is, an amount of air commensurate with the vacuum exhaust amount required to maintain a predetermined negative pressure in the box body of the wall surface traveling device, is negative. It is flowing into the pressure side. In a steady state, the pressure from the negative pressure side acting on the valve element and the force of the coil spring are in balance with the dynamic pressure of the inflowing air. In order to actuate the valve element immediately in response to a minute change in pressure difference, it is necessary to make the air flow through the valve orderly. Therefore, in the negative pressure regulating valve of the present invention, the inside of the case is formed axially symmetrical, and the diameter of the coil spring is set to a size close to the inner surface of the case to prevent turbulence of the air flow and form an air flow parallel to the axis. , A tapered air flow is passed through the ring-shaped opening as a cylindrical air flow. Further, the air flow is bent at a right angle on the surface of the valve element 4 and is introduced so as to be uniformly distributed in the radial direction between the valve seat and the valve element opened at a small interval. A parallel surface is formed between the valve seat and the valve body that are in surface contact with each other by opening the valve body, and within a certain range, the opening degree, that is, the interval and the change in the pressure difference are proportional. When traveling, for example, if the airtightness is broken by the unevenness of the wall surface causing air to flow and the pressure on the negative pressure side rises, the pressure on the negative pressure side acts directly on the valve body. Moves instantaneously in the closing direction to reduce the valve opening or closes, and the amount of air flowing in through the valve decreases or becomes zero. The pressure increment which this negative pressure regulating valve detects and operates is 0.01 Bar as mentioned above.
Since the blower is continuously operated, the pressure on the negative pressure side drops, and the above-mentioned increase in pressure disappears. If the amount of leaked air decreases due to the improvement of the sealed state, the negative pressure inside the box body is restored and the pressure on the back surface of the valve body 4 decreases, so the valve body 4 opens greatly in proportion to the increase in the pressure difference. If the valve body is opened beyond a certain limit, the proportional relationship between the change in pressure difference and the opening degree of the valve is lost, but the large amount of inflowing air increases the pressure on the negative pressure side and cancels the pressure drop. As described above, in the negative pressure regulating valve of the present invention, if the amount of air discharged from the negative pressure side space is constant, the total amount of air flowing into the negative pressure side space including air leakage is kept constant. Acting, thereby maintaining the pressure on the suction side at a predetermined value. By guiding the valve rod by using a guide having a ball bearing as the guide means, the valve rod can be prevented from being caught due to twisting or bending of the spring due to expansion and contraction, and operation can be performed with good responsiveness.

【Example】

Embodiments of the negative pressure regulating valve of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view of an embodiment of a low pressure negative pressure regulating valve of the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a bottom view. As shown in these figures, this negative pressure adjusting valve for low pressure includes a valve seat member 1, a case 2 having a bottomed cylindrical body for holding the valve seat member 1, and an opening 3 of the valve seat member 1 from the negative pressure side. A flat disc-shaped valve body 4 to be opened and closed, a valve rod 5 having the valve body 4 attached to one end, a ball bearing 7 for guiding the valve rod 5 axially with respect to the valve seat member 1, and a valve seat member 1 to the case 2 Fixed to the guide post 6 having a space for accommodating the ball bearing 7,
The coil spring 9 surrounds the portion of the guide post 6 that houses the ball bearing, and biases the valve body 4 toward the valve seat via the valve rod 5. The coil spring 9 has a spring receiving member 8 at one end on the upper end of the valve rod 5.
, And the other end is fixed to the guide post 6,
The valve body 4 is in close contact with the valve seat by the compressive force acting there. The valve body 4 is attached by a nut 11 to a guide bolt 10 (integrated with the valve rod 5) provided on the valve rod 5. The case 2 is mounted on the positive pressure side O via a seal 13 to the partition wall member 12 whose upper end flange section divides the positive pressure side O and the negative pressure side I from each other. A cover 14 is attached to the upper surface of the flange portion of the case 2. In this configuration, when the air on the negative pressure side I is continuously discharged at a constant rate by the vacuum generator B of the wall surface traveling device shown in FIG. 6, the valve is on the negative pressure side as shown in FIG. It is opened at an opening that maintains the pressure of I constant, and air flows in from the positive pressure side O at a constant rate through the path indicated by the arrow in the figure. As described above, the width of the valve opening is such that even at the maximum opening of the valve body, a negative pressure sufficient to keep the wall surface traveling device adsorbed on the wall surface can be formed. There is nothing to do. In the normal state, the force of the coil spring 9 acting on the valve element 4 and the negative pressure are balanced, and the pressure on the negative pressure side I is maintained at a predetermined value. As mentioned above, the pressure on the suction side I or some cause,
For example, due to movement of the wall surface traveling device or riding on an obstacle, air leaks from between the negative pressure seal S and the wall surface W into the inside of the box A, the pressure on the negative pressure side I rises, and the pressure difference becomes small. Then, the equilibrium state collapses, the pressure behind the valve body rises, the valve body 4 approaches the valve seat, the flow rate of the air flowing through the valve decreases, and the vacuum generator I sucks the negative pressure side I. Pressure decreases and returns to the pressure before fluctuation. When the pressure on the negative pressure side I falls for some reason, the pressure on the back surface of the valve body decreases, the valve body 4 separates from the valve seat, and the flow rate of air passing through the valve increases, so that the pressure on the negative pressure side I reaches a predetermined value. Restoring to, as already mentioned. Since the pressure on the negative pressure side I acts directly from behind the valve body 4, that is, directly on the surface on the negative pressure side, the movement of the valve body is rapid, and the changed negative pressure instantaneously returns to a predetermined value. When the valve body 4 moves up and down, the coil spring 9 works to keep the valve rod 5 perpendicular to the surface of the valve seat, so that the valve body 4 can be smoothly moved up and down. In this way, in order to keep the pressure value on the negative pressure side I at a desired value even in spite of slight pressure fluctuations, the spring constant of the compression spring 9 and the valve seat member 1, the valve body 4 and particularly the valve seat 1 are kept constant. It is necessary to appropriately design the size of the opening 3 and the like. As described above, the size of the opening 3 is determined by the minimum negative pressure to be maintained on the negative pressure side. The flat disc-shaped valve body 4 preferably has a diameter 1.5 times or more the diameter of the opening. This corresponds to a diameter difference of 10 mm or more in the negative pressure regulating valve used for the wall surface traveling device that is currently being prototyped. With such a size of the valve body, the static pressure of the negative pressure side space can act directly behind the valve body without generating a vortex of the air flow behind it. The spring constant may be selected so that the amount of opening of the valve body, that is, the displacement position of the spring is about 1.0 mm due to the force generated according to the area of the opening 3 with respect to the pressure change of 0.01 Bar. With a proper design, the negative pressure regulating valve of the present invention has a desired negative pressure with a restoration time of 0.5 seconds or less even when the pressure change due to leaked air is 0.01 Bar or less at a low negative pressure of about 0.7 to 1.0 Bar. The pressure can be maintained. The pattern is shown in FIG. 7 in comparison with the conventional valve. INDUSTRIAL APPLICABILITY The negative pressure regulating valve of the present invention is particularly useful when it is used in a wall surface traveling device that directly cools exhaust air as a cooling medium for a blower. That is, in the normal case where the vehicle is running on a smooth surface, the valve is opened to allow air to flow because the seal with the wall surface of the negative pressure space is good, and it is possible to secure the air volume necessary for cooling the blower, and Therefore, when an air leak occurs, the valve is closed instantly to prevent the pressure from rising and prevent the wall surface traveling device from falling. At this time, the supply of the cooling air is stopped for a short time, but the valve is opened soon and the circulation of the air is restarted, so that there is substantially no influence on the cooling.

【The invention's effect】

As described above, the negative pressure regulating valve of the present invention is a pressure regulating valve that keeps the pressure constant while introducing air into the negative pressure space to be formed, which is lightweight, has a simple structure, and can be configured compactly, Even in the negative pressure region, the pressure change on the negative pressure side can be accurately adjusted by instantaneously reacting to the pressure change. Therefore,
It is possible to maintain adsorption to the wall surface of the wall surface traveling device that could not be realized with the conventional pressure control valve, which is useful for practical application of the wall surface traveling device with improved performance. By guiding the valve rod using the ball bearing, the valve can be moved smoothly without the spring being twisted or bent, and the reliability and responsiveness can be further improved. In particular, when a blower of the direct cooling type is used, the amount of gas discharged from the negative pressure side is almost constant and can be effectively used.

[Brief description of drawings]

FIG. 1 is a partial longitudinal sectional view showing an embodiment of the negative pressure regulating valve of the present invention, FIG. 2 is a plan view, and FIG. 3 is a bottom view. FIG. 4 is an explanatory view corresponding to FIG. 1, showing the operating principle of the negative pressure regulating valve. FIG. 5 is a vertical cross-sectional view showing an example of a conventional negative pressure regulating valve. FIG. 6 is a conceptual sectional view of a wall surface traveling device using the negative pressure regulating valve of the present invention. FIG. 7 is an explanatory diagram showing the time required to recover the degree of vacuum by the negative pressure adjusting valve of the present invention in comparison with the conventional valve. DESCRIPTION OF SYMBOLS 1 ... Valve seat member, 2 ... Case, 3 ... Opening part, 4 ... Valve body, 5
... valve rod 6 ... guide post, 7 ... ball bearing, 8 ... spring receiving member, 9 ... spring A ... box, B ... vacuum generator, S ... negative pressure seal, W ... wall surface O ... positive pressure side, I ... negative Pressure side

Claims (1)

[Claims] 1. A box body is formed by forming a closed space with a box body on a wall surface, while constantly evacuating the inside thereof, while allowing air to flow in through a negative pressure adjusting valve to maintain a negative pressure in the closed space. In a negative pressure control valve used in a wall surface traveling device that travels while adsorbing the air on a wall surface, the bottom of a case having a bottomed cylindrical body that divides the surrounding positive pressure space and negative pressure space is opened, and this opening And a valve seat member that has an annular tapered surface that is inclined in the direction of restricting the flow of air flowing into the valve and that projects beyond the opening to form an annular valve seat at the end of the tapered surface. , A valve rod extending through the opening in the axial direction of the tubular body, having at one end a disc-shaped valve body that contacts the valve seat from the outside and at the other end with a spring receiving member, Allows movement, itself fixed to the case and bearing inside It has a cylindrical shape and its lower part is attached by a guide post located inside the opening to enable opening and closing of the valve, and a coil spring with a diameter located near the inner surface of the case is provided between the inside of the bottom of the case and the spring receiving member. The valve rod is biased in the valve closing direction by a compressive force, the valve body is brought into surface contact with the valve seat to form a valve, and the inflowing air flows in a flow parallel to the axial direction of the tubular body. It is configured so that it is narrowed by the tapered surface to form a cylindrical flow, passes through the opening portion, hits the disc-shaped valve element, changes its direction in the radial direction, and is uniformly dispersed and flows into the closed space. However, while a constant pressure difference is maintained between the upstream (positive pressure) side and the downstream (negative pressure) side of the valve, a certain amount of air corresponding to the vacuum exhaust amount flows while the valve is open. To maintain the specified pressure difference while allowing air to leak into the enclosed space. When the pressure rise exceeds 0.01 Bar due to the pressure rise on the negative pressure side that acts directly behind the valve body, the valve body is moved by the force of the coil spring and the valve closes, and the air equivalent to the leakage amount from the closed space is closed. A negative pressure regulating valve, which is configured to recover a predetermined pressure difference within 0.5 seconds by eliminating the negative pressure.