Vacuum gate valve

Abstract

This invention provides a vacuum gate valve that prevents the valve body from sliding toward the valve seat and mitigates the impact during valve body operation. [Solution] The valve body 20 connected via a stem 21 is driven in the opening and closing direction by a valve body opening and closing drive unit 3, which is provided with a cylinder mechanism 4 and a cam mechanism 5. The cylinder mechanism 4 has a piston 50 and an extension piston 51, and an air chamber 56 is provided at the top of the cylinder chamber 55. When the extension piston 51 enters the air chamber 56, it compresses the air to increase the resistance when the piston 50 rises, and a vent 65 is provided on the middle side of the extension piston 51, and when this vent 65 enters the air chamber 56, it releases the air in the air chamber 56 to reduce the resistance when the piston 50 rises.

Description

Technical Field

[0001] The present invention relates to a gate valve for vacuum, and more particularly to a gate valve for vacuum used for opening and closing a flow path when carrying in and out wafers, substrates, etc. such as semiconductors, solar cells, and liquid crystals.

Background Art

[0002] In this type of gate valve for vacuum, the valve body is moved in the upward direction and then horizontally with respect to the sealing surface on the body side, thereby preventing the sliding of the valve body with respect to the valve seat surface and suppressing the generation of particles and dust when the valve is closed. There is a known device that attempts to suppress this. In such a so-called two-step operation type gate valve, when the valve body switches from the upward movement to the horizontal movement, there is a device that attempts to suppress the impact on the upper end side due to the upward movement of the valve body.

[0003] As this type of gate valve, for example, Patent Document 1 is disclosed. In this gate valve, an abutting spring is provided that attenuates the braking of the closing unit that drives the valve body in the vertical displacement direction and the horizontal displacement direction. The abutting spring has spring legs, and the upper end side of the raised closing unit abuts against these spring legs, thereby decelerating the speed of the raised closing unit by the abutting spring and attempting to delay or reduce the generated impact.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the gate valve for vacuum having a structure that drives the valve body in a two-step operation of lifting and horizontal movement, in addition to the upward movement of the valve body, when the valve body abuts against the valve seat surface during the horizontal movement of the valve body, there is a possibility of generating an impact.

[0006] In contrast, the gate valve described in Patent Document 1 uses the elastic force of the spring leg of the contact spring to dampen the upward speed of the blocking unit as it rises. Moreover, the elastic force of the spring leg functions only at the moment the upward movement of the blocking unit is complete, and the operating range in which the upward speed of the blocking unit is dampened is narrow.

[0007] Therefore, the above-mentioned contact spring cannot absorb the impact over the wide range of the valve's movement, from the stage when the valve body finishes its upward movement to the stage when it finishes its horizontal movement. In particular, it is difficult to mitigate the impact when the valve body sits on the valve seat surface during horizontal movement, which may cause vibration, noise, or particle generation when the valve is closed. Thus, the inability to adequately absorb the impact during valve movement results in durability problems.

[0008] In addition, after the closure unit contacts the spring leg of the contact spring, the closure unit is decelerated to a nearly constant upward speed by the constant elastic force of this spring leg, and this decelerated upward speed of the valve body does not change even when the closure unit finishes rising. Therefore, it is difficult to sufficiently decelerate the operating speed of the valve body when the closure unit finishes rising, and it is difficult to effectively absorb the impact.

[0009] As described above, the spring leg elastically deforms at a constant rate, and since the deformation rate does not change, it takes time from the moment the closure unit makes contact until the upward movement is completed. This may increase the overall time required for the valve body to open and close.

[0010] Furthermore, since the braking force of the closing unit is dampened by contact with the contact spring, repeated upward and downward movements of the closing unit may cause the contact spring to wear out, reducing its elastic force and potentially making it difficult to adequately mitigate the closing shock.

[0011] The present invention was developed to solve the problems of the past, and its objective is to provide a gate valve that can prevent the valve body from sliding toward the valve seat, and a vacuum gate valve that mitigates the impact during valve body operation. [Means for solving the problem]

[0012] To achieve the above objective, the invention according to claim 1 has a valve body opening / closing drive body that drives a valve body connected via a stem in the opening and closing direction, the valve body opening / closing drive body is provided with a cylinder mechanism that moves the valve body up and down, and a cam mechanism that moves the valve body raised by the cylinder mechanism horizontally to close the valve, the cylinder mechanism has a piston that moves up and down by supplying air to a cylinder chamber provided inside it to raise the valve body to a position where the cam mechanism operates, and an extension piston provided on the tip side of the piston, an air chamber is provided at the top of the cylinder chamber into which the extension piston enters when the piston rises, the air in the air chamber is compressed when the extension piston enters the air chamber to increase the resistance when the piston rises, and a vent is provided on the middle side of the extension piston, which is a cutout of at least a part of the outer diameter side of the extension piston, the air in the air chamber is released from the vent when the vent enters the air chamber to reduce the resistance when the piston rises.

[0013] The invention according to claim 2 is a vacuum gate valve in which a valve body opening / closing drive body is disposed inside a frame-shaped housing body, and a roller is provided in the housing body that contacts the upper part of the valve body opening / closing drive body to restrict its upward position while guiding the valve body horizontally, and when at least the tip side of the extension piston has entered the air chamber, the upper part of the valve body opening / closing drive body contacts the roller and restricts its upward movement.

[0014] The invention according to claim 3 is a vacuum gate valve in which, with the rear end of the extension piston entering the air chamber, the valve body moves horizontally by a cam mechanism to close the valve.

[0015] The invention according to claim 4 is a vacuum gate valve in which the contact state of the upper part of the valve body opening / closing drive unit with the roller is maintained from the time the extension piston starts to enter the air chamber until it exits.

[0016] The invention according to claim 5 is a vacuum gate valve in which an air chamber is provided with a communication hole that communicates with the outside and releases the air inside the air chamber when the extension piston enters the air chamber, thereby adjusting the entry speed of the extension piston.

[0017] The invention according to claim 6 is a vacuum gate valve in which the ventilation portion is a concave portion or groove formed on the outer circumference near the middle portion of the extension piston. [Effects of the Invention]

[0018] According to the invention of claim 1, the valve body opening and closing drive unit equipped with a valve body is a two-stage operation type comprising a cylinder mechanism for raising and lowering the valve body and a cam mechanism for closing the valve body by horizontal movement. This allows for valve opening and closing while preventing the valve body from sliding toward the valve seat when the valve is closed. The cylinder mechanism has a piston and an extension piston at the tip of the piston. When the extension piston enters the air chamber at the top of the cylinder chamber, the air is compressed to increase the resistance when the piston rises, thereby reducing the operating speed of the valve body as the piston rises. This ensures responsiveness during valve body operation and suppresses impact not only during the upward movement of the valve body but also when the valve body contacts the valve seat surface during horizontal movement. In this way, by reliably absorbing impact over a wide operating range from near the end of the upward movement of the valve body to the end of the horizontal movement, durability is improved, vibrations are suppressed, and valve body operation becomes smoother. Furthermore, as the amount the extended piston enters the air chamber increases, the resistance during piston ascent gradually increases. This provides a significant deceleration effect, particularly near the end of the valve's upward movement and the end of its horizontal movement, minimizing the impact at the end of operation, preventing vibration and noise, and avoiding particle generation. On the other hand, since a ventilation section is provided on the intermediate side of the extension piston, with at least a portion of the outer diameter of the extension piston cut out, when this ventilation section passes the air chamber inlet, the air in the air chamber is released to the outside through the ventilation section, reducing the resistance when the piston rises, and allowing the piston to rise and fall faster in this section. As a result, the opening and closing speed of the valve body from the open state to the closed state, or from the closed state to the open state, is also improved, and the valve opening and closing operation can be performed in a short time.

[0019] According to the invention of claim 2, the valve body opening / closing drive body is provided with a frame-shaped housing body on which a roller is provided to guide the valve body opening / closing drive body horizontally to the valve body, while the upper part of the valve body opening / closing drive body abuts against the roller to restrict its upward position. With at least the tip of the extension piston entering the air chamber, the upper part of the valve body opening / closing drive body abuts against the roller to restrict its upward movement, thereby reliably mitigating the impact during the upward movement of the valve body opening / closing drive body and improving durability.

[0020] According to the invention of claim 3, when the rear end of the extension piston enters the air chamber, the valve body moves horizontally by the cam mechanism to close the valve, thereby mitigating the impact during the horizontal movement of the valve body, improving durability, and preventing the generation of particles.

[0021] According to the invention of claim 4, the extension piston is kept in the air chamber from the stage when the valve body, which is particularly prone to impact, finishes its upward movement to the stage when the valve body moves horizontally and finishes its valve closing movement. This cushions the impact within the valve body's opening and closing range through the compression of air by the extension piston.

[0022] According to the invention of claim 5, by releasing air from the air chamber through a communication hole provided in the air chamber, the entry speed of the extension piston can be adjusted, thereby achieving both shock mitigation during valve body elevation and rapid elevation of the valve body. Furthermore, by setting the type of material constituting the inlet of the air chamber according to the temperature used and setting the entry speed of the extension piston according to the characteristics of this material, it is possible to improve the sealing performance and durability of the air chamber inlet.

[0023] According to the invention according to claim 6, the ventilation part provided in the middle part of the extension piston is provided in an appropriate notch shape such as a concave part or a groove part, and the air release speed from the air chamber can be adjusted by adjusting the notch depth and the notch width, and can be set to the desired operating speed of the piston.

Brief Description of the Drawings

[0024] [Figure 1] (a) is a longitudinal sectional view showing the valve opening state of an embodiment of the vacuum gate valve of the present invention. (b) is a partial omitted central longitudinal sectional view of (a). [Figure 2] (a) is a longitudinal sectional view showing the state where the valve body opening / closing driver in FIG. 1(a) has risen. (b) is a partial omitted central longitudinal sectional view of (a). [Figure 3] (a) is a longitudinal sectional view showing the state where the valve body in FIG. 2(a) has horizontally moved to the valve closing position. (b) is a partial omitted central longitudinal sectional view of (a). [Figure 4] (a) is a schematic sectional view showing the state before the extension piston enters the air chamber. (b) is a schematic sectional view showing the start state of the extension piston entering the air chamber. (c) is a schematic sectional view showing the state in the middle of the extension piston entering the air chamber. [Figure 5] (a) is a partially enlarged sectional view showing the vicinity of the roller. (b) is a partially enlarged sectional view showing the vicinity of the seal part of the valve body. [Figure 6] It is a schematic diagram showing the mounting state of the roller block on the stem.

Embodiments for Carrying out the Invention

[0025] Embodiments of the vacuum gate valve according to the present invention will be described in detail based on the drawings. FIG. 1 is a sectional view showing an embodiment of the vacuum gate valve of the present invention, and FIGS. 2 and 3 are sectional views showing the state where the valve body has moved.

[0026] In the figure, the vacuum gate valve according to the present invention (hereinafter referred to as gate valve 1) is used, for example, in a semiconductor manufacturing apparatus as a valve that opens and closes a wafer transport passage leading to a vacuum chamber, in an environment of about 120°C. In the figure, the gate valve 1 comprises a body 2 and a valve body opening / closing drive unit 3. The valve body opening / closing drive unit 3 is mounted so as to be able to move up and down relative to the body 2, and this valve body opening / closing drive unit 3 is equipped with a cylinder mechanism 4 and a cam mechanism 5.

[0027] Body 2 comprises a rectangular body body 10 and a frame-shaped housing 11, with the housing 11 integrally attached to the lower part of the body body 10. The body 10 forms a fluid channel and is provided in a frame shape that can be connected to the wafer transport passage described above. A rectangular slit 12, which is a fluid channel, is formed in the center of the body. A valve seat surface 13 is formed on the outer circumference of the slit 12, and a valve body can be seated on this valve seat surface 13.

[0028] The valve body opening / closing drive unit 3 includes a valve body (gate) 20, a stem 21, a stem holder 22, two roller blocks 23, two cam plates 24, and a base plate 25. The valve body 20 is attached to the upper end of the stem 21, and as shown in Figure 5(b), a sealing O-ring 26 is fitted to its primary side. In Figures 1 to 3, a stem holder 22 is fixed to the lower end of the stem 21. The stem holder 22 is shaped like a rectangular parallelepiped with a bottomed mounting hole 22a in its center. The lower end of the stem 21 is inserted into this mounting hole 22a, and the stem 21 is fixed to the stem holder 22 from the bottom side with a fixing bolt 27.

[0029] The two roller blocks 23 are formed from long plate material in a symmetrical shape, and their upper parts are fixed to the sides of the stem holder 22. Two elongated cam grooves 28, as shown in Figure 6, are formed vertically on the outer surface of each roller block 23 at a predetermined interval in the vertical direction. The two cam grooves 28 are formed with a predetermined width that allows the guide roller 31 (described later) to be inserted, and are formed at the same inclination angle, sloping from the lower to the upper part of the roller block 23 from the primary side to the secondary side of the valve body. A plate member 30 for shock absorption is fixed to the upper surface of each roller block 23.

[0030] As shown in Figures 1 to 3, with the above configuration, the valve body 20, stem 21, stem holder 22, and roller block 23 are integrally formed, and in the valve body opening / closing drive unit 3, these are provided so as to be drivable in the vertical direction of the valve body 20 by the cam plate 24.

[0031] Each cam plate 24 is formed from a long plate material, similar to the roller block 23, and is positioned opposite the roller block 23 on the outside, sandwiching them. The lower ends of these cam plates 24 are fixed to the base plate 25, which is the bottom plate of the valve body opening / closing drive unit 3, and are provided to move up and down integrally with the base plate 25.

[0032] Each cam plate 24 is provided with multiple guide rollers 31. In this case, an outer guide roller 32 is provided on the housing body 11 side, which is the outside of the cam plate 24, and an inner guide roller 33 is provided on the stem holder 22 side, which is the inside of the cam plate 24. The outer guide rollers 32 are arranged in a line of three in the vertical direction and are engaged with guide grooves 41, which will be described later, formed in the columnar cylinder portions 40 provided on both sides of the housing body 11. They are provided so as to be able to rotate and move while being guided vertically along these guide grooves 41.

[0033] The inner guide rollers 33 are arranged in a vertical direction in two locations, and these two inner guide rollers 33 are fixed coaxially with the outer guide rollers 32 located on the upper and lower sides of the three outer guide rollers 32 arranged as described above.

[0034] The two inner guide rollers 33 are engaged with the upper and lower cam grooves 28 of the aforementioned roller block 23, and are provided to be rotatable and movable while being guided vertically along these cam grooves 28. In Figure 6, the inner guide rollers 33 shown by solid lines represent the state in which the cam plate 24 is lowered relative to the roller block 23, as shown in Figures 1 and 2, while the inner guide rollers 33 shown by dashed lines represent the state in which the cam plate 24 is raised relative to the roller block 23, as shown in Figure 3. The outer guide roller 32 and the inner guide roller 33 are provided, for example, by cam followers.

[0035] With respect to the cam plate 24, the valve body 20, which is integrated with the roller block 23 via a stem holder 22 through a cam groove 28, is able to move up and down along the shape of the cam groove 28. With respect to the housing body 11, the piston 50 and extension piston 51, described later, are able to move up and down vertically along the shape of the guide groove 41 via a piston rod 52 through a guide groove 41, via the cam plate 24 and a base plate 25 fixed to the cam plate 24.

[0036] A spring 53, made of a coil spring, is installed in a resilient state in the space between the bottom surface of the stem holder 22 and the top surface of the base plate 25. The resilient force of this spring 53 biases the roller block 23 and the stem holder 22, stem 21, and valve body 20 fixed to the roller block 23 in an upward direction relative to the base plate 25, so that when the valve is open, the stem 21 and the base plate 25 are pulled apart from each other. At this time, because the roller block 23 is mounted on the cam plate 24 with the inner guide roller 33 engaged with the cam groove 28, even when the resilient force of the spring 53 is at its maximum, the roller block 23 will rise relative to the cam plate 24 with its range of movement restricted.

[0037] With the above configuration, the stem holder 22's movement is restricted by the left and right roller blocks 23, and these roller blocks 23 are guided by the upper and lower inner guide rollers 33 and the coaxial outer guide roller 32. As a result, the stem holder 22 moves up and down together with the piston rod 52 while receiving the elastic force of the spring 53.

[0038] The cylinder mechanism 4 is located inside the aforementioned housing 11 and includes a piston 50, a piston rod 52, an extension piston 51, a cylinder chamber 55, and an air chamber 56. This cylinder mechanism 4 allows the valve body opening / closing drive unit 3 to move up and down relative to the housing 11.

[0039] The piston rod 52 has its lower end connected to both sides of the cam plate 24 on the base plate 25, and the piston 50 is integrally fixed to its tip. An extension piston 51 is fixed to the tip of the piston 50, and in this configuration, the piston 50 and the extension piston 51 are arranged to operate integrally with the base plate 25 via the piston rod 52.

[0040] The cylinder chamber 55 is located inside the cylinder section 40, and compressed air at, for example, 0.4 to 0.6 MPa is supplied from an external air supply unit (not shown) that is connected to the lower and upper sides of the piston 50 in the cylinder chamber 55.

[0041] An upper frame portion 60 is attached to the upper side of the cylinder portion 40, connecting the cylinder portion 40 to the main body 10. An air chamber 56, smaller in volume than the cylinder chamber 55, is provided on the side of the upper frame portion 60 opposite the cylinder chamber 55, so as to communicate with the cylinder chamber 55. In this way, the air chamber 56 is positioned above the cylinder chamber 55, and the extension piston 51 is provided to enter the air chamber 56 when the piston 50 is raised.

[0042] An annular sealing member 61 made of V-packing is installed on the inlet side of the air chamber 56, and this sealing member 61 is capable of sealing the tip 51a side and the rear end 51b side of the extension piston 51, which will be described later. The sealing member 61 is preferably made of a rubber material such as nitrile rubber (NBR) when the temperature is 70°C or lower, and preferably made of fluororubber such as polyvinylidene fluoride rubber (FKM) when the temperature is higher than 70°C.

[0043] A communication hole 62 is provided inside the air chamber 56, which connects the air chamber 56 to the outside. The communication hole 62 allows air inside the air chamber 56 to escape when the extension piston 51 enters the air chamber 56, thereby reducing the resistance caused by the air inside the air chamber 56 when the extension piston 51 enters, and making it possible to adjust the entry speed of the extension piston 51.

[0044] The piston 50 is provided to move up and down within the cylinder chamber 55 by supplying air to the cylinder chamber 55, and is provided to be able to raise the valve body 20 to the position in which the cam mechanism 5 operates.

[0045] In Figures 4(a) to 4(c), the tip 51a and rear end 51b of the extension piston 51 are provided with an outer diameter approximately the same as the inner diameter of the sealing member 61 on the inlet side of the air chamber 56. When the tip 51a or rear end 51b of the extension piston 51 enters the air chamber 56, the size of the outer diameters of these tip 51a and rear end 51b compresses the air in the air chamber 56, increasing the resistance when the piston 50 rises.

[0046] The tip portion 51a and the rear portion 51b described above may be provided so as to be slightly smaller in diameter than the inner diameter of the sealing member 61 on the inlet side of the air chamber 56, and a small gap may be provided between them. Furthermore, the extension piston 51 may be formed in a shape that has a tip portion 51a and a ventilation portion 65 (described later) without a rear end portion 51b.

[0047] Chamfered portions 51c are provided on the upper and lower surfaces of the tip portion 51a of the extension piston 51, and on the upper surface of the rear end portion 51b.

[0048] As described above, by providing a chamfered portion 51c on the extension piston 51, when the extension piston 51 enters the air chamber 56, the chamfered portion 51c prevents the tip 51a from catching when it contacts the inner circumference end of the seal member 61, thereby preventing wear of the seal member 61 due to being drawn into the air chamber 56. At the same time, until the tip 51a of the extension piston 51 enters the air chamber 56 (from Figure 4(a) to Figure 4(b)), the tip 51a compresses the air in the air chamber 56, increasing the resistance when the piston 50 rises. This increased resistance slows down the operation (upward movement) of the extension piston 51 until the tip 51a enters the air chamber 56, thereby mitigating the impact that would otherwise occur on the entire gate valve 1.

[0049] On the other hand, when the rear end 51b of the extension piston 51 reaches the seal member 61, the aforementioned chamfered portion 51c on the upper surface of the rear end 51b prevents the rear end 51b from catching when it comes into contact with the inner circumference end of the seal member 61, preventing wear of the seal member 61 due to being drawn into the air chamber 56. At the same time, until the lower surface of the rear end 51b of the extension piston 51 enters the air chamber 56 (from Figure 4(c) until the upper surface of the extension piston 51 contacts the top surface of the air chamber 56 or stops before contacting it), the rear end 51b compresses the air in the air chamber 56, increasing the resistance when the piston 50 rises. This increase in resistance slows down the operation (rising motion) of the extension piston 51 until the lower surface of the rear end 51b enters the air chamber 56, thereby mitigating the impact that would otherwise occur on the entire gate valve 1.

[0050] An air vent 65 is formed in the intermediate portion of the extension piston 51 between its tip 51a and rear end 51b, such that it is cut out to at least a portion of the outer diameter of the tip 51a and rear end 51b. In this embodiment, this air vent 65 is provided by an annular groove. When the intermediate portion of the extension piston 51 is positioned relative to the air chamber 56, the air chamber 56 is in communication with the outside (outside air) through the annular groove 65, which serves as a communication section.

[0051] By providing the ventilation section 65 and communication hole 62 described above, as shown in Figures 4(a) to 4(c), when the extension piston 51 enters the air chamber 56, the air in the air chamber 56 is released to the outside through the ventilation section 65 and communication hole 62, preventing the air in the air chamber 56 from becoming excessively compressed, and reducing the resistance when the piston 50 rises.

[0052] The communication hole 62 described above is the part through which air is released to the outside as a result of the extension piston 51 compressing the air in the air chamber 56. On the other hand, the wider the area of ​​the ventilation section 65, the less resistance the piston 50 experiences when it rises. Therefore, the communication hole 62 and the ventilation section 65 are formed such that the amount of air released from the communication hole 62 is less than the amount of air released from the ventilation section (annular groove) 65. In this way, by always ensuring that the amount of air released from the ventilation section 65 is greater than the amount of air released from the communication hole 62, excessive resistance to the upward movement of the extension piston 51 (piston 50) is prevented.

[0053] Furthermore, in the portion of the extension piston 51 where the ventilation section 65 is provided, the air in the air chamber 56 is continuously released through the ventilation section 65 and the communication hole 62, which reduces the resistance when the extension piston 51, i.e., the piston 50, rises, and increases the upward speed of the piston 50.

[0054] When the length of the extension piston 51 and the cross-sectional shape of the ventilation section 65 remain constant, the elapsed time when the operating speed of the piston 50 is increasing is related to the ratio of the length of the ventilation section 65 to the length of the extension piston 51. The larger this ratio, the shorter the elapsed time when the speed is increasing.

[0055] Therefore, for example, by increasing the ratio of the length of the ventilation section 65 to the length of the extension piston 51, and decreasing the ratio of the length of the tip section 51a and the rear section 51b, the proportion of elapsed time when the piston 50 speed increases can be increased, and the piston 50 can be moved in the valve closing direction in a short time. On the other hand, by reducing the ratio of the length of the ventilation section 65 to the length of the extended piston 51, and increasing the ratio of the lengths of the tip section 51a and the rear section 51b, the proportion of time elapsed when the piston 50 speed increases is reduced, and the resistance when the piston 50 rises is increased, thereby further mitigating the impact that would otherwise occur in the entire gate valve 1.

[0056] As described above, the ventilation portion 65 is provided by a concave portion or groove formed on the outer circumference of the extension piston 51 near the middle portion, consisting of a constricted annular groove. The annular groove (ventilation portion) 65 may be made narrower if it can withstand the impact received when the extension piston 51 enters the air chamber 56.

[0057] When the extension piston 51 (piston 50) descends, contrary to when it rises, the upper surface of the extension piston 51 is separated from the top surface or near the top surface of the air chamber 56, allowing it to descend, as shown in Figure 4(c). At this time, that is, when moving from the valve closed state to the valve open state, the chamfered portion 51c on the upper surface side of the rear end 51b of the extension piston 51 advances downward from above the seal member 61. On the other hand, the seal member 61 is formed so that its end is inclined toward the direction of the downward movement of the extension piston 51. As a result, when it comes into contact with the chamfered portion 51c of the extension piston 51, wear of the seal member 61 is prevented, and air is gradually drawn into the air chamber 56 from the communication hole 62 until the rear end 51b of the extension piston 51 exits the air chamber 56, thereby increasing the resistance when the piston 50 descends.

[0058] This increase in resistance slows down the operation of the piston 50 in the state shown in Figure 4(c) until the rear end 51b of the extension piston 51 exits the air chamber 56. This reduces the impact on the entire gate valve 1, as well as reducing the sliding between the valve seat surface 13 and the valve body 20, which helps prevent the generation and scattering of dust and other debris.

[0059] As the piston descends from Figure 4(c) to Figure 4(b), the air in the air chamber 56 is released to the outside through the vent 65 and the communication hole 62, preventing the air in the air chamber 56 from becoming compressed and reducing the resistance when the piston 50 descends. In this case, according to the relationship mentioned above, where the amount of air released from the communication hole 62 is less than the amount of air released from the vent (annular groove) 65, outside air is gradually drawn into the air chamber 56 from the communication hole 62 and the vent 65 in accordance with the downward movement of the piston 50. This makes it possible to reduce the resistance when the piston 50 descends at this time.

[0060] Furthermore, while the ventilation portion 65 is positioned against the sealing member 61, air continues to be drawn in from the ventilation portion 65 and the communication hole 62, maintaining a reduced resistance during the downward movement of the piston 50. As a result, the downward speed of the extended piston 51, i.e., the piston 50, increases.

[0061] As mentioned above, the elapsed time when the operating speed of the piston 50 is increasing is related to the ratio of the length of the ventilation section 65 to the length of the extension piston 51, and the larger this ratio, the shorter the elapsed time when the speed is increasing.

[0062] Therefore, for example, by increasing the ratio of the length of the ventilation section 65 to the length of the extension piston 51, and decreasing the ratio of the lengths of the tip section 51a and the rear section 51b, the proportion of elapsed time when the piston 50 speed increases can be increased, allowing the piston 50 to move in the valve opening direction in a short time. On the other hand, by reducing the ratio of the length of the ventilation section 65 to the length of the extended piston 51, and increasing the ratio of the lengths of the tip section 51a and the rear section 51b, the proportion of time elapsed when the piston 50 speed increases is reduced, and the resistance when the piston 50 descends is increased, thereby further mitigating the impact that would otherwise occur in the entire gate valve 1.

[0063] In the state shown in Figure 4(b), after the sealing member 61 has passed through the ventilation section 65, the chamfered portion 51c prevents the tip portion 51a from catching when it comes into contact with the inner circumferential end of the sealing member 61, and prevents wear of the sealing member 61 when the tip portion 51a moves outward from the air chamber 56. In the state from Figure 4(b) to Figure 4(a), until the upper surface of the tip portion 51a exits the air chamber 56, the sealing member 61 either contacts the outer surface of the tip portion 51a so as to block it, or it does not contact it but the space is extremely narrow. The same is true when the outer surface of the rear end portion 51b passes relatively through the sealing member 61.

[0064] As a result of the above operation, when the piston 50 descends, air is gradually drawn into the air chamber 56 through the communication hole 62, increasing the resistance when the piston 50 descends. This increase in resistance slows down the movement (descending movement) of the extension piston 51 until the upper surface of the tip 51a exits the air chamber 56 (from Figure 4(b) to Figure 4(a)), thereby mitigating the impact that would otherwise occur in the entire gate valve 1.

[0065] The cam mechanism 5 is provided between the valve body opening / closing drive unit 3 and the housing body 11, and is configured to operate the valve body 20, which has been raised by the cylinder mechanism 4, to a closed or open state by horizontal movement. In the gate valve 1, the valve body opening / closing drive unit 3 operates via the aforementioned cylinder mechanism 4 and the cam mechanism 5, opening and closing the slit (flow path) 12 of the body 10. In addition to the roller block 23, cam plate 24, guide roller 31, and spring 53 described above, the cam mechanism 5 is equipped with a guide groove 41 and a roller 71.

[0066] The guide grooves 41 are formed by straight grooves oriented vertically near the center of the inside of each cylinder portion 40 on both sides. The outer guide rollers 32 engage with these guide grooves 41, and the valve body opening / closing drive unit 3 is positioned inside the housing 11 while being guided vertically by these grooves.

[0067] The outer guide rollers 32 engage with the guide groove 41 in different ways depending on the vertical movement of the valve body opening / closing drive unit 3. For example, when the valve body opening / closing drive unit 3 is at its highest point, all of the outer guide rollers 32 are engaged with the guide groove 41. On the other hand, when the valve body opening / closing drive unit 3 is at its lowest point, the top two outer guide rollers 32 are engaged with the guide groove 41. In this way, when the valve body opening / closing drive unit 3 is moving up and down, at least two of the outer guide rollers 32 are engaged with the guide groove 41, so that the valve body opening / closing drive unit 3 is always supported at two or more points on the left and right sides, and wobbling is suppressed.

[0068] The roller 71, like the guide roller 31, is a cam follower and is positioned on the upper frame portion 60 of the housing body 11 where it contacts the plate member 30 provided on the upper side of the valve body opening / closing drive unit 3 when it is raised. When the valve body opening / closing drive unit 3 is raised by the cylinder mechanism 4, the maximum height of the valve body 20 is restricted by contact with the roller 71. Furthermore, the roller 71 has the function of guiding the valve body 20 in the horizontal direction while restricting the upward position of the valve body opening / closing drive unit 3.

[0069] In this case, with at least the tip 51a of the extension piston 51 entering the air chamber 56, the upper plate member 30 of the valve body opening / closing drive unit 3 is in contact with the roller 71, as shown in Figure 5(b), and is configured to restrict its upward movement. In other words, when the valve body opening / closing drive unit 3 rises due to the cylinder mechanism 4 and its upper part (plate member 30) contacts the roller 71, the tip 51a of the extension piston 51 is in a state just before entering the seal member 61 on the inlet side of the air chamber 56. That is, the tip 51a of the extension piston 51 enters the air chamber 56 from the state where the upper part of the valve body opening / closing drive unit 3 is in contact with the roller 71.

[0070] Furthermore, even when the rear end 51b of the extension piston 51 enters the air chamber 56, the upper part of the valve body opening / closing drive unit 3 remains in contact with the roller 71. With the rear end 51b of the extension piston 51 in this state entering the air chamber 56, the valve body 20 moves horizontally, which is the opening / closing direction, by the cam mechanism 5, and the valve closes.

[0071] As described above, the contact state of the upper part of the valve body opening / closing drive unit 3 with the roller 71 is maintained from the time the extension piston 51 starts to enter the air chamber 56 until it exits. In other words, the contact state of the upper part of the valve body opening / closing drive unit 3 with the roller 71 is maintained during the operation from just before the valve body opening / closing drive unit 3 switches from the lifting operation by the cylinder mechanism 4 to the horizontal operation by the cam mechanism 5 until the valve body 20 is closed by the cam mechanism 5.

[0072] The valve body opening / closing drive unit 3 is positioned inside the housing body 11 in the structure described above. When air is supplied to the air chamber 56 and the piston 50 moves up and down, causing the base plate 25 and the cam plate 24 to move up and down together via the piston rod 52, the valve body opening / closing drive unit 3 moves up and down as guided by the guide groove 41 via the engagement of the inner guide roller 33 with the cam groove 28 and the engagement of the outer guide roller 32 with the guide groove 41, thereby causing the valve body 20 to move up and down together with it.

[0073] In the gate valve 1 shown in Figure 1, when the valve is open, the spring 53 becomes elastically biased, and the upper and lower inner guide rollers 33 engage with the lower end of the cam groove 28, causing the roller block 23 to rise while its upward position is restricted relative to the cam plate 24.

[0074] On the other hand, in Figure 3, when the gate valve 1 is closed, a force is applied to the roller block 23 in a direction that causes the cam plate 24 to rise. As a result, the spring 53 is compressed and deformed, and the upper and lower inner guide rollers 33 engage with the upper end of the cam groove 28, causing the roller block 23 to descend with its lower position restricted relative to the cam plate 24.

[0075] Furthermore, the gate valve 1 of the present invention has a valve body opening / closing drive unit 3, and the valve body opening / closing drive unit 3 is equipped with a cylinder mechanism 4 for raising and lowering the valve body 20, and a cam mechanism 5 for horizontally moving the valve body 20 that has been raised by the cylinder mechanism 4, and the cylinder mechanism 4 is equipped with a piston 50 and the aforementioned extension piston 51, so it is also possible to provide it with various configurations other than the internal structure described above.

[0076] The ventilation portion 65 is formed in the middle of the extension piston 51 and can be any shape other than a concave or grooved portion, as long as it allows air in the air chamber 56 to escape when the extension piston 51 enters. It can also be provided in various forms other than a notched shape.

[0077] The outer guide rollers 32 of the cam plate 24 are provided at three locations in the vertical direction, but they may also be provided at only two locations, top and bottom.

[0078] Next, the operation and function of the vacuum gate valve of the present invention in the above embodiment will be described. First, we will describe the operation of gate valve 1 when it changes from the open state shown in Figure 1 to the closed state. In the valve open state shown in Figure 1, the valve body opening / closing drive unit 3 is shown in a lowered position relative to the housing body 11. At this time, the piston 50 is in the lowered position, and the piston rod 52, base plate 25, and cam plate 24, which are integrated with the piston 50, are also in a lowered position. As a result, the inner guide roller 33 mounted on the cam plate 24 is locked to the bottom side of the cam groove 28, as shown by the solid line in Figure 6. This locking of the inner guide roller 33 to the cam groove 28 causes the roller block 23, stem holder 22, stem 21, and valve body 20 fixed to the stem 21 to also lower, opening the slit 12 and opening the valve.

[0079] From this state, when air is supplied to the lower side of the piston 50 in the cylinder chamber 55 and pressurized, the piston 50 rises due to this air pressure, and the base plate 25 fixed to the piston rod 52 also rises. At this time, the stem 21, which is integrated with the stem holder 22, is pushed up relative to the base plate 25 by the elastic force of the spring 53, so the stem holder 22 and the stem 21, as well as the valve body 20 and roller block 23 attached to the stem 21, rise together. In this case, because the inner guide roller 33 is engaged with the cam groove 28, as the roller block 23 rises, the outer guide roller 32 is guided by the guide groove 41 and the cam plate 24 also rises.

[0080] In Figure 2, when the upper part of the roller block 23 contacts the roller 71, the upward movement of the roller block 23 stops, and the valve body 20 rises to a position opposite the slit 12. At this time, the upper surface of the plate member 30 provided on the upper surface of the roller block 23 contacts the roller 71, which mitigates the impact when the roller block 23 rises and stops, and also provides noise reduction, while the operation of the valve body opening / closing drive unit 3 stops.

[0081] In this case, the roller block 23 and stem holder 22 are restrained in the left-right direction by the engagement of the outer guide rollers 32 with the guide groove 41, through the cam groove 28 of the roller block 23, the upper and lower inner guide rollers 33, and the upper and lower outer guide rollers 32 which are coaxial with the inner guide rollers 33. In addition, the stem holder 22 and the roller block 23 are pressed against the bottom of the cam groove 28 of the roller block 23 by the elastic biasing force of the spring 53, so that their vertical positional relationship with the cam plate 24 remains approximately constant.

[0082] As described above, the stem holder 22 and roller block 23 rise while their positions are restricted in the vertical and horizontal directions, allowing the valve body 20, which is fixed to the stem holder 22 via the stem 21, to rise while preventing rattling in the vertical and horizontal directions.

[0083] During the intermediate stages of the upward movement of the valve body opening / closing drive unit 3, the plate member 30 contacts the roller 71 to restrict its upward movement when at least the tip 51a side of the extension piston 51 has entered the air chamber 56. Since the tip 51a side has an outer diameter approximately the same as the inner diameter of the sealing member 61 at the inlet of the air chamber 56, when the extension piston 51 begins to enter the air chamber 56, its tip 51a side tightly seals against the inner circumference of the sealing member 61, closing the inlet side of the air chamber 56. Therefore, as the tip 51a enters the air chamber 56, the compression ratio of the air in the air chamber 56 by the extension piston 51 increases, and the resistance increases proportionally as the piston 50 rises.

[0084] In this way, the entry of the extension piston 51 into the air chamber 56 compresses the air in the air chamber 56, which activates the damping function of the cylinder mechanism 4. This reduces the upward speed of the valve body opening / closing drive unit 3, causing the upper part of the valve body opening / closing drive unit 3 to contact the roller 71. Subsequently, this upward movement by the cylinder mechanism 4 can be converted into a horizontal movement by the cam mechanism 5, thus reliably mitigating shocks during operation.

[0085] In Figure 2, with the roller block 23 (plate member 30) in contact with the roller 71, when the lower side of the piston 50 is further pressurized with air, this air pressure causes the piston rod 52 and the cam plate 24 fixed to the base plate 25 to rise further, while the base plate 25 compresses the spring 53.

[0086] In this case, a ventilation portion 65, which is made up of a concave groove with at least a part of the outer diameter cut out, is provided in the middle of the extension piston 51. As the piston rises with the middle portion reaching the position of the seal member 61, the compressed air in the air chamber 56 is released to the outside from the inlet side through the ventilation portion 65. Therefore, compared to when the tip portion 51a rises above the seal member 61, the resistance due to the air in the air chamber 56 is greatly reduced, and in the section where the ventilation portion 65 passes above the seal member 61, the upward speed of the piston 50 accelerates and the upward time is shortened.

[0087] Furthermore, in Figure 3, as the inner guide roller 33 rises in the cam groove 28, the cam groove 28 is inclined from the lower part to the upper part of the roller block 23 from the primary side (left side) to the secondary side (right side) of the valve body, as shown in Figure 6, so the inner guide roller 33 rises vertically. At this time, the roller block 23 moves towards the primary side (left side) as the roller slides along the plate member 30, guided by the cam groove 28.

[0088] The rear end 51b of the extension piston 51 has an outer diameter that is approximately the same as the inner diameter of the sealing member 61 at the inlet of the air chamber 56. Therefore, when this rear end 51b enters the air chamber 56, it tightly seals against the inner circumference of the sealing member 61, closing the inlet side of the air chamber 56. In this case, as the amount of entry of the rear end 51b into the air chamber 56 increases, the compressibility of the air in the air chamber 56 tends to increase. However, air in the air chamber 56 escapes to the outside through the communication hole 62, preventing a sudden decrease in the upward speed of the piston 50 while maintaining a damping function.

[0089] As described above, the outer diameters of the tip 51a and rear end 51b of the extension piston 51 are such that they increase the resistance when the piston 50 rises when the piston is in the raised position. Therefore, when the piston 50 rises and the tip 51a or rear end 51b of the extension piston 51 enters the air chamber 56, the upward speed of the piston 50 decreases, mitigating the impact. In particular, when the rear end 51b enters the air chamber 56, the vent 65 accelerates the upward speed, shortening the upward speed of the piston 50, while gradually decreasing its upward speed. This effectively dampens the impact caused by the valve body 20 moving to contact the valve seat surface 13 from the opposite direction.

[0090] When the extension piston 51 described above enters the air chamber 56, the upward thrust of the cam plate 24 is converted into a horizontal driving force for the roller block 23. The stem holder 22, stem 21, and valve body 20 move to the primary side (left side) along with the roller block 23, and the O-ring 26 provided on the valve body 20 is pressed against the valve seat surface 13 and seated, resulting in a closed seal state. When the O-ring 26 contacts the valve seat surface 13, its elastic force also mitigates the impact when the valve body 20 seats, improving durability. In addition, it improves dust resistance, reliably preventing the generation of particles. When the valve is closed as shown in Figure 3, the inner guide roller 33 is locked to the upper side of the cam groove 28 of the roller block 23, as shown by the dashed line in Figure 6.

[0091] Next, to change the valve from the closed state in Figure 3 to the open state, air is supplied to the upper side of the piston 50 in the cylinder chamber 55 to pressurize it. As a result, the base plate 25 and the cam plate 24 begin to descend via the piston rod 52, and in the opposite direction to the valve closing operation described above, the inner guide roller 33 provided on the cam plate 24 descends vertically, and guided by the cam groove 28, the roller block 23 moves to the secondary side (right side). Along with this, the stem 21 and valve body 20 also move to the secondary side (right side), and the O-ring 26 separates from the valve seat surface 13.

[0092] In this case, the stem holder 22 and the roller block 23 are pressed against the upper part of the cam groove 28 of the roller block 23 by the elastic force of the spring 53, so that the vertical positional relationship with the cam plate 24 remains approximately constant. In addition, the roller block 23 and stem holder 22 are restrained in the left-right direction by the engagement of the outer guide rollers 32 with the guide grooves 41, through the cam grooves 28 of the roller block 23, the upper and lower inner guide rollers 33, and the upper and lower outer guide rollers 32.

[0093] As a result, when the cam plate 24 descends, a downward force acts from the inner guide roller 33 to the roller block 23. However, because the spring 53 exerts an upward force on the stem holder 22, the valve body 20 moves horizontally relative to the valve seat surface 13. Therefore, particle generation is suppressed even when the valve body 20 separates.

[0094] Next, in the opposite motion to the valve opening operation described above, the piston 50 descends, along with the piston rod 52 and the base plate 25. At this time, the inner guide roller 33 moves downward in the cam groove 28, causing the cam plate 24 to descend.

[0095] As the cam plate 24 descends, the inner guide roller 33 engages with the bottom of the cam groove in Figure 6. This engagement of the inner guide roller 33 causes the valve body 20, along with the roller block 23, stem holder 22, and stem 21, to move to the secondary side (right side), resulting in the valve open state shown in Figure 1.

[0096] According to the gate valve 1 of the above embodiment of the present invention, by supplying air into the cylinder chamber 55, the valve body 20 is moved vertically and horizontally in a two-stage operation by the cylinder mechanism 4 and the cam mechanism 5, and the valve body 20 can be opened and closed while suppressing sliding with the valve seat surface 13.

[0097] In this case, since an extension piston 51 is provided on the piston 50, the lifting and lowering speed of the valve body 20 can be adjusted via this extension piston 51, improving responsiveness to air supply and smoothly switching between vertical and horizontal movement of the valve body 20, thereby improving the overall durability of the gate valve 1. For example, it can withstand repeated opening and closing operations of about 3 million times. When the valve body 20 approaches and separates from the valve seat surface 13, the movement of the valve body 20 can be further decelerated, reliably preventing the generation of particles and dust.

[0098] When the tip 51a of the extension piston 51 enters the air chamber 56, it mainly exerts a buffering force during the vertical movement of the valve body 20 by the cylinder mechanism 4, and when the rear end 51b of the extension piston 51 enters the air chamber 56, it mainly exerts a buffering force during the horizontal movement of the valve body 20 by the cam mechanism 5. In this way, it is possible to prevent the occurrence of shocks over a wide range of motion from near the end of the vertical movement of the valve body 20 to the opening and closing operation by horizontal movement.

[0099] The ventilation section 65 in the middle of the extension piston 51 shortens the time it takes for the piston 50 to move up and down when passing through the inlet side of the air chamber 56, thus enabling the gate valve 1 to open and close in a short time and allowing for rapid opening and closing control. As described above, the compression of air by the entry of the extension piston 51 into the air chamber 56 dampens the braking force during the lifting and lowering operation of the valve body opening / closing drive unit 3. This prevents wear on the internal components and eliminates the risk of a decrease in the damping function due to this braking.

[0100] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention as described in the claims of the present invention. [Explanation of symbols]

[0101] 1 Gate valve 3. Valve body opening / closing drive unit 4-cylinder mechanism 5 Cam mechanism 11 Housing Body 20 valve body 21 Stem 50 pistons 51 Extension piston 51a Tip 51b Rear end 55 Cylinder Chamber 56 Air chamber 62 Communication hole 65 Annular groove (ventilation section) 71 Laura

Claims

1. The valve body has a valve body opening / closing drive unit that drives a valve body connected via a stem in the opening and closing direction, and this valve body opening / closing drive unit is provided with a cylinder mechanism that moves the valve body up and down, and a cam mechanism that moves the valve body raised by the cylinder mechanism to a horizontal position to close the valve, and the cylinder mechanism has a piston that moves up and down by supplying air to a cylinder chamber provided inside it to raise the valve body to a position where the cam mechanism operates, and an extension piston provided on the tip side of the piston, An air chamber is provided at the top of the cylinder chamber, into which the extension piston enters when the piston rises. As the extension piston enters the air chamber, it compresses the air inside the air chamber, thereby increasing the resistance when the piston rises. The extension piston is provided with a ventilation section on the intermediate side, which is a cutout of at least a portion of the outer diameter side of the extension piston. A vacuum gate valve characterized in that, when the vent portion enters the air chamber, it releases the air in the air chamber from the vent portion, thereby reducing the resistance when the piston rises.

2. The valve body opening / closing drive unit is arranged inside a frame-shaped housing, and the housing is provided with a roller that contacts the upper part of the valve body opening / closing drive unit to restrict its upward position while guiding the valve body horizontally. The vacuum gate valve according to claim 1, wherein, with at least the tip of the extension piston entering the air chamber, the upper part of the valve body opening / closing drive unit contacts the roller and restricts its upward movement.

3. The vacuum gate valve according to claim 2, wherein the valve body moves horizontally by the cam mechanism when the rear end of the extension piston enters the air chamber, thereby closing the valve.

4. The vacuum gate valve according to claim 2 or 3, wherein the contact state of the upper part of the valve body opening / closing drive unit with the roller is maintained from the time the extension piston starts to enter the air chamber until it exits.

5. The vacuum gate valve according to claim 1, wherein the air chamber is provided with a communication hole that communicates with the outside to release the air inside the air chamber when the extension piston enters the air chamber and adjusts the entry speed of the extension piston.

6. The vacuum gate valve according to claim 1, wherein the ventilation portion is a concave portion or groove formed on the outer circumference near the middle portion of the extension piston.

Images