JP2005230935A - Throttle valve for pneumatic tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throttle valve 20 in which an operation load is not increased even if driven with compressed air in a high-pressure region and by which the regulation of a flow rate of the compressed air can be easily executed. <P>SOLUTION: The throttle valve 20 is composed of a valve housing 22, which forms a main flow passage 24 for supplying the compressed air to an air motor 4, and a sleeve valve 25 which is housed in the valve housing 22 and operated by a valve stem 38 subjected to sliding operation via a throttle lever 21 so as to open/close the main flow passage 24. Both end parts of the sleeve valve 25 are released to the air. An effective cross-sectional area difference part, on which the compressed air acts, is formed between a first seal member 27 for cutting off the main flow passage 24 mounted to the sleeve valve 25 and a second seal member 31 arranged to one end side of the sleeve valve. The sleeve valve 25 is pressed in the direction of closing the main flow passage 24 by the action of the compressed air acting on the effective cross-sectional area difference part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a compressed air tool in which an air motor is rotationally driven by compressed air to perform screw tightening, bolt tightening, or drilling, and in particular, compression for controlling the flow rate of compressed air supplied to an air motor by operating a throttle lever. The present invention relates to a pneumatic tool throttle valve.

  An impact driver that rotates an air motor with compressed air supplied from an air compressor and rotates a driver bit, socket, or drill bit by the rotational force of the air motor to perform screwing, bolting, or drilling. In this tool, the other end of the air hose, one end of which is connected to the compressed air supply source, is connected to the tool, and the compression supplied to the tool through the air hose by operating the throttle lever provided on the tool. Air is supplied to the air motor to rotate the air motor. In such a tool such as a driver, a wrench or a drill, a throttle is provided so that the flow rate of the compressed air supplied to the air motor can be varied according to the operation amount of the throttle lever operated by the hand holding the tool. A valve is configured, and an operator controls the rotation of the air motor while adjusting the pulling operation of the throttle lever to perform screw tightening and drilling operations.

A throttle valve employed in a conventional impact driver or the like is formed at the upper end of the throttle sleeve by operating a large-diameter throttle sleeve upward by a small-diameter throttle rod that is pushed up by an operator operating the throttle knob. The valve body is separated from the valve seat formed on the bush to open the flow path. Compressed air supplied from a compressed air supply source is supplied to the upper surface side of the valve body, and this compressed air acts on the upper surface side of the valve body to press the valve body in the closing direction. . Therefore, a pressing force of compressed air acting on the valve body acts on the throttle knob, and an operation load is increased.
JP-A-11-58265

In addition to the normal pressure tool that is driven by compressed air in the normal pressure range of 10 kg / cm ² or less that has been used conventionally, the high pressure range that is higher than the pressure in the normal pressure range and does not exceed 50 kg / cm ² In recent years, high-pressure dedicated tools driven by compressed air have been used. By driving with such a high-pressure tool, a high-power tool can be formed in a small size and light weight, so workability can be improved. When driving the impact driver with compressed air in the high pressure range, if the mechanism of the throttle valve of the conventional impact driver for normal pressure is used as it is, the high pressure compressed air acts on the end of the valve body of the throttle valve and the throttle The operation load of the throttle knob that operates the rod will increase. For this reason, a tool that adjusts the flow rate of compressed air according to the operation amount of the throttle knob, such as an impact driver, makes it difficult to adjust the subtle operation amount and makes it difficult to work. There is.

  The present invention solves the above-described problems in the prior art, and does not increase the operation load even when driven by compressed air in a high pressure range, so that the amount of compressed air supplied to the air motor can be easily adjusted. It is an object of the present invention to provide a throttle valve.

  In order to solve the above problems, a throttle valve of a compressed air tool according to the present invention includes an air motor driven by compressed air, and a throttle valve operated by a compressed lever supplied with compressed air supplied from a compressed air supply source. In the compressed air tool which is supplied to the air motor via the air motor and drives the air motor, the throttle valve forms a main flow path for supplying the compressed air supplied from the compressed air supply source to the air motor. A housing, and a sleeve valve that is accommodated in the valve housing and is operated to open and close the main flow path via a valve stem that is slid by a throttle lever. Both ends of the guide sleeve that slidably accommodates the part An effective cross-sectional area difference in which compressed air acts is formed between a first seal member mounted on a sleeve valve for blocking the main flow path and a second seal member disposed in the guide sleeve. The sleeve valve is pressed in the direction of closing the main flow path by the action of compressed air acting on the effective cross-sectional area difference portion.

  According to a second aspect of the present invention, the end portion of the guide sleeve accommodating one end side of the sleeve valve is opened to the outer surface of the housing, and one end is communicated with the opening on the outer surface of the housing. The other end is formed with a recessed groove that is opened at a portion away from the outer surface of the housing, the outer surface of the housing is covered with a grip cover, and an exhaust passage is formed between the grip cover and the outer surface of the housing. And

  The first seal member and the guide attached to the sleeve valve that opens both ends of the guide sleeve that slidably accommodates both ends of the sleeve valve that opens and closes the main flow path to the atmosphere and that blocks the main flow path An effective cross-sectional area difference in which compressed air acts is formed between the second seal member arranged in the sleeve, and the main flow path is closed by the action of the compressed air acting on the portion of the effective cross-sectional area difference. Since the load acting in the direction of closing the sleeve valve by the compressed air can be set small, the flow rate of the throttle valve by the throttle lever with the tool operated by the high-pressure compressed air can be set. Subtle adjustments can be made easily and workability is improved.

  Further, in the invention of claim 2, the end portion side of the guide sleeve accommodating one end side of the sleeve valve is opened to the outer surface of the housing, and one end is communicated with the opening on the outer surface of the housing. Since the end is formed with a concave groove that is opened at a distant portion of the outer surface of the housing, and the outer surface of the housing is covered by the grip cover, an exhaust passage is formed between the grip cover and the outer surface of the housing. The opening is not closed by the grip cover, one end side of the throttle valve can be reliably opened to the atmosphere, and the operation of the sleeve valve can always be performed lightly.

  An object of the present invention is to open and close the main flow path for the purpose of facilitating adjustment of the amount of compressed air supplied to the air motor without increasing the operation load even when driven by compressed air in a high pressure range. Both ends of the guide sleeve that slidably accommodates both ends of the sleeve valve are opened to the atmosphere, and a first seal member mounted on the sleeve valve for blocking the main flow path and a first seal member disposed in the guide sleeve are disposed. An effective cross-sectional area difference in which compressed air acts between the two seal members is formed, and the sleeve valve is pressed in the direction of closing the main flow path by the action of the compressed air acting on the effective cross-sectional area difference portion. More specific examples will be described below.

  FIG. 1 is a longitudinal side view showing an impact driver as an example of a compressed air tool in which a throttle valve of the present invention is implemented. The impact driver 1 is integrally formed with a handle portion 2 for gripping the impact driver 1 during operation. The housing 3 is formed, and an air motor 4 that is rotationally driven by compressed air supplied into the impact driver 1 is disposed on one end side of the housing 3. The impact mechanism 6 driven by the air motor 4 is accommodated. The output shaft 5 of the air motor 4 is connected to the impact mechanism 6 so as to rotate the impact hammer 7 of the impact mechanism 6, and the impact hammer 7 is driven to rotate via the air motor 4 so that the anvil 8 is hit and the anvil is driven. A shocking rotational force is transmitted to 8. The front end portion of the anvil 8 is disposed so as to protrude outward from the end portion on the other end side of the housing 3, and a chuck portion for detachably attaching a driver bit to the front end portion of the anvil 8. 9 is formed.

  The handle portion 2 is formed in a hollow shape, and an air chamber 10 in which compressed air to be supplied to the air motor 4 is stored and exhausted from the air motor 4 after driving the air motor 4 are inside the hollow portion of the handle portion 2. Exhaust chambers 11 for storing the exhaust air to be stored are formed in parallel. A plug 12 for connecting the impact driver 1 to a socket attached to the other end of the air hose whose one end is connected to a compressed air supply source is attached to the rear end of the air chamber 10. Compressed air is supplied to the air chamber 10 through the plug 12.

  As shown in detail in FIG. 2, the plug 12 is formed in a plug shape exclusively for high pressure used in a compressed air supply system in a high pressure region. In conventional high-pressure plugs used in tools such as compressed air-operated nailers that have a large capacity air chamber that stores high-pressure compressed air inside, a reverse flow occurs when the air hose is removed. The hole at the tip is formed small and radially so that the compressed air in the air chamber is ejected radially from the tip of the plug. For this reason, in the case of a tool that is operated in a state in which air is always flowed, such as an air motor, this hole acts as a throttle and becomes a flow resistance of the compressed air, and the pressure of the compressed air immediately before the air motor 4 Decreases and the output decreases.

  According to the present embodiment, as shown in FIG. 3A, a supply port 14a having a large hole for allowing compressed air to flow through the tip 14 of the plug 12 and a supply port 14b having a small diameter formed on the outer periphery of the tip 14 are formed. As a result, the effective area through which the high-pressure compressed air flows is increased. As a result, the flow rate of the compressed air through the plug 12 increases, and the pressure of the compressed air immediately before the air motor 4 can be maintained high, so that the output of the air motor 4 does not decrease. Furthermore, as shown in FIG. 3B, a radial slit 15 may be formed at the tip 14 of the plug 12 to increase the opening area of the supply port in the tip direction. Thus, by improving the supply performance of the high-pressure compressed air through the plug 12, the tightening time per screw can be shortened, and as a result, the air consumption when tightening the screw is reduced. Followability is improved. Since the impact driver 1 is not formed with a large air chamber like a nail driver, the plug 12 can be removed from the hose even if the large-area supply ports 14a and 15 directed toward the distal end of the plug 12 are formed. In this case, since the amount of compressed air ejected from the tip 14 of the plug 12 is small, the blowing sound does not increase.

  The compressed air that has actuated the air motor 4 is exhausted to the atmosphere through an exhaust chamber 11 and an exhaust portion 13 formed at the rear end of the handle portion 2. As shown in detail in FIG. 4, an exhaust filter is formed in the exhaust portion 13 to reduce the flow rate of the compressed air exhausted to the atmosphere and prevent the dust and wood chips on the work site from being blown up. The exhaust filter is constituted by a filter case 16 formed in a cylindrical shape and a filter material 17 accommodated in the filter case 16. When high-pressure compressed air is used, the amount of compressed air discharged from the exhaust section 13 to the atmosphere increases. Therefore, the filter device used in the conventional normal pressure tool is used to reduce the exhaust flow rate. Also, the opening area of the exhaust port 18 formed in the filter case 16 is formed large. Further, as shown in FIG. 5, the filter material 17 is formed by winding a fine wire mesh in a spiral shape and accommodating the filter material in a cylindrical shape in a cylindrical filter case 16 to constitute an exhaust filter. Since the wire mesh is wound and used as the filter material 17 in this way, it is necessary to dispose the wire mesh on the inner peripheral surface of the filter case 16 in order to prevent the filter material 17 from being blown out from the exhaust port 18. Cost reduction is possible.

  Reference numeral 19 in FIG. 1 indicates that the compressed air in the air chamber 10 is supplied to the atmosphere when the pressure of the compressed air in the air chamber 10 supplied from the compressed air supply source becomes higher than the pressure for driving the impact driver 1. It is a relief valve for discharging and preventing the pressure in the air chamber 10 from becoming higher than a predetermined driving pressure.

  A throttle valve 20 for supplying compressed air supplied into the air chamber 10 to the air motor 4 is formed at the base portion of the handle portion 2 and is rotatably supported by the base portion of the handle portion 2. The throttle lever 21 is operated by the finger of the hand holding the handle portion 2 so that the throttle valve 20 is operated to supply compressed air to the air motor 4 to rotate the air motor 4. As shown in FIGS. 1 and 6, the throttle valve 20 includes a hollow valve housing 22 that is disposed so as to penetrate the exhaust chamber 11 of the handle portion 2 and reach the air chamber 10 at the tip end portion. An opening 23 is formed on the outer peripheral wall of the upper portion of the valve housing 22 so that the hollow space of the valve housing 22 communicates with the air chamber 10. The compressed air in the air chamber 10 is formed downstream of the opening 23. Is formed through the hollow of the valve housing 22 to be supplied to the air motor 4.

  A hollow sleeve valve 25 that opens and closes the main flow path 24 is accommodated in the hollow of the valve housing 22, and a flange portion 26 having an enlarged outer diameter is integrated in the middle portion of the sleeve valve 25. A first O-ring 27 as a first seal member attached to the base portion of the flange portion 26 is fitted into the main channel 24 of the valve housing 22, whereby the main channel 24. Is closed and the first O-ring 27 deviates from the main flow path 24, thereby opening the main flow path 24 and supplying compressed air to the air motor 4 through the hollow space of the valve housing 22. The sleeve valve 25 is urged in a direction in which the first O-ring 27 is fitted into the main flow path 24 by a spring 28 acting on the flange portion 26. The sleeve valve 25 is actuated by engaging the flange 26 with a shoulder 29 formed on the upstream side of the main flow path 24 with the first O-ring 27 fitted in the main flow path 24. The position is determined.

  A second O-ring 29 as a seal member is mounted on the outer peripheral surface on the left end side of the sleeve valve 25 in the figure, and the second O-ring 29 is disposed in the hollow guide sleeve 30 disposed in the valve housing 22. The sleeve valve 22 is slidably accommodated, and a third O-ring 31 as a second seal member is mounted on the right end side of the sleeve valve 22 in the figure, and the third O-ring 31 is attached to the end of the valve housing 22. Is slidably accommodated in a guide sleeve 32 held by the housing 3. The inner diameters of the guide sleeves 30 and 32 that house both ends of the sleeve valve 25 are formed to be the same, and therefore the outer diameters of the second O-ring 29 and the third O-ring 31 are formed to be the same. Further, the end portions of the guide sleeves 30 and 32 that accommodate both ends of the sleeve valve 25 are open to the atmosphere so that the compressed air does not act on both ends of the sleeve valve 25.

  Further, an opening 33 is formed in the peripheral wall in the vicinity of the flange portion 26 formed in the sleeve valve 25 so as to communicate between the hollow inside of the sleeve valve 25 formed hollow and the air chamber 10. A sub-flow path 34 that is formed in a tapered shape that allows the air chamber 10 to communicate with the inside of the sleeve valve 25 is formed. A ball valve 36 biased by a spring 35 is disposed in the tapered sub-channel 34, and the ball valve 36 is in close contact with the back of the sub-channel 34 formed in a taper shape. As a result, the compressed air from the air chamber 10 is blocked from flowing into the hollow of the sleeve valve 25. Further, when the ball valve 36 is separated from the inner portion of the sub-flow path 34 against the urging force of the spring 35, compressed air enters the sleeve valve 25 and is formed on the peripheral wall of the sleeve valve 25. The air motor 4 is supplied via the opening 37. The clearance between the ball valve 36 and the inner peripheral surface of the sub-channel 34 increases as the ball valve 36 moves from the back of the sub-channel 34 formed in a tapered shape to the right in the figure, and the ball valve 36 is compressed accordingly. The flow rate of air flowing to the air motor 4 is changed.

  A valve stem 38 for operating the sleeve valve 25 and the ball valve 36 is slidably disposed in the hollow of the sleeve valve 25. The left end side of the valve stem 38 in the figure protrudes from the end of the valve housing 22 and is disposed so as to face the throttle lever 21. The valve stem 38 is slid by rotating the throttle lever 21. It can be operated. The right end of the valve stem 38 in the figure is arranged to face the ball valve 36, and when the valve stem 38 is slid by a predetermined stroke by operating the throttle lever 21, the ball stem is pushed by the tip of the valve stem. The valve 36 is operated so as to be separated from the inner part of the sub flow path 34. Further, a flange 39 having a large outer diameter is formed on the left end side of the valve stem 38 in the figure, and when the valve stem 38 is further slid by operating the throttle lever 21, the flange 39 Engages with the end face of the sleeve valve 25 and slides the sleeve valve 25 in the right direction in the drawing to cause the first O-ring 27 blocking the main flow path 24 to deviate from the main flow path 24. The main flow path 24 is opened.

  The diameter of the first O-ring 27 is slightly larger than the diameters of the second O-ring 29 and the third O-ring 31, and an effective cross-sectional area where compressed air acts between the first O-ring 27 and both the O-rings 29, 31. Forming a difference. Accordingly, the compressed air that has entered between the first O-ring 27 and the third O-ring 31 of the sleeve valve 25 through the opening 23 formed in the valve housing 22 acts on the effective cross-sectional area difference portion so that the sleeve valve 25 is effectively cut off. The main flow path 24 is pushed in the closing direction by the area difference. As a result, the load when the sleeve valve 25 is opened by the valve stem 38 can be reduced.

  A right end in the figure of the guide sleeve 32 that slidably accommodates one end side of the sleeve valve 25 is opened on the outer surface of the housing 3, and the outer surface of the housing 3 is continuous with this opening. A concave groove 40 is formed, and a ventilation path is formed between the housing 3 and a rubber grip cover 41 mounted so as to cover the outer surface of the housing 3. The end portion of the air passage formed by the concave groove is continued to the portion where the grip cover 41 is not attached, and thereby, one end side of the sleeve valve 25 is closed by the grip cover 41 attached to the outer surface of the housing. Therefore, it is possible to prevent the operation load of the sleeve valve from becoming heavy.

  Hereinafter, the operating state of the throttle valve will be described with reference to FIGS. As shown in FIG. 6, when the throttle lever 21 is not operated, the compressed air supplied to the sleeve valve 25 through the opening 23 formed in the valve housing 22 is the first O-ring 27 and the third O-ring 31. Between the first O-ring 27 and the third O-ring 31 and the compression air pressure acting on the effective cross-sectional area difference between the first O-ring 27 and the third O-ring 31 and the spring 28 pressing and urging the sleeve valve 25. The first O-ring 27 of the sleeve valve 25 is fitted into the main flow path 24 by the biasing force, and the main flow path 24 is closed. Compressed air also acts on the ball valve 36, and the ball valve 36 is fitted in the back of the sub-flow path 34 formed in a tapered shape by the action of the compressed air and the urging force of the spring 25. The flow path 34 is closed.

  When the throttle lever 21 is rotated by the finger of the hand holding the handle portion 2 and the valve stem 38 is slid, the valve stem 38 is slid rightward in the drawing as shown in FIG. Then, the tip end of the valve stem 38 abuts on the ball valve 36 and the ball valve 36 is pressed by the compressed air acting on the ball valve 36 and the biasing force of the spring 35 pressing and biasing the ball valve 36. Against this, the sub-channel 34 is opened away from the back of the tapered sub-channel 34. As a result, compressed air supplied to the air chamber 10 through the plug 12 flows into the hollow of the sleeve valve 25 formed in a hollow shape, and an opening 37 formed in the peripheral wall of the sleeve valve 25 is formed. Then, the air motor 4 is supplied to the air motor 4 via the supply path 42 and is driven to rotate.

  As shown in FIG. 8, the moving position of the ball valve 36 via the valve stem 38 can be adjusted by adjusting the amount of rotation of the throttle lever 21 to adjust, thereby forming a taper shape. The air flow area formed between the inner peripheral surface of the sub flow path 34 and the outer peripheral surface of the ball valve 36 is variably adjusted, the amount of air supplied to the air motor 4 is adjusted, and the rotation speed of the air motor 4 can be adjusted as appropriate. During the adjustment operation of the ball valve 36 as described above, the compressed air only acts on the valve stem 38 having a small diameter, so that the throttle lever 21 has a pressing force of the compressed air acting on the valve stem 38 and the ball valve 36. Only the urging force of the spring 35 urging the air motor 4 can be used, and the rotation of the air motor 4 can be adjusted and operated via the throttle lever 21 with a light acting force.

  When the throttle lever 21 is further rotated, as shown in FIG. 9, the valve stem 21 is further slid rightward in the figure, and the flange 39 formed on the outer periphery of the valve stem 21 is the left end of the sleeve valve 25. The sleeve valve 25 together with the valve stem 21 is moved rightward in the figure. As the sleeve valve 25 is slid and moved in this manner, the first O-ring 27 deviates from the main flow path 24 formed in the valve housing 22 and the main flow path 24 is opened. The air is supplied to the outer peripheral surface side of the sleeve valve 25 via the main flow path 24 and supplied to the air motor 4 so that the air motor 4 is driven to rotate. The sleeve valve 25 has an effective cross-sectional area difference between a first O-ring 27 that closes the main flow path 24 and a third O-ring 31 that is attached to the right end of the sleeve valve 25. Pressure is acting on the sleeve valve 25 in the direction in which the first O-ring 27 closes the main flow path 24 by the pressure of the compressed air acting between the O-rings, but this effective cross-sectional area difference is formed small. Therefore, even when high-pressure compressed air acts, the load for opening the sleeve valve 25 by the throttle lever 21 via the valve stem 38 is small. Therefore, the operation of the throttle valve 20 via the throttle lever 21 can be performed easily.

1 is a longitudinal side view of an impact driver according to an embodiment of the present invention. Detailed sectional view showing the air plug (A) And (b) is a perspective view which shows the edge part of the plug of a different shape, respectively. Detailed sectional view showing the exhaust section Perspective view showing the exhaust filter Detailed sectional view of the throttle valve portion in the impact driver of FIG. Vertical side view of the same throttle valve as FIG. 6 showing the operating state with the ball valve opened Vertical side view of the same throttle valve as in FIG. 6 showing the operating state with the ball valve opened more widely A longitudinal side view of the same throttle valve as in FIG. 6 showing an operating state in which the main flow path is opened by operating the sleeve valve

Explanation of symbols

1 Impact driver (compressed air tool)
20 Throttle valve 21 Throttle lever 22 Valve housing 24 Main flow path 25 Sleeve valve 27 First O-ring (first seal member)
31 3rd O-ring (second seal member)
34 Sub-flow path 36 Ball valve 38 Valve stem

Claims (2)

  A compression system that includes an air motor driven by compressed air and that supplies compressed air supplied from a compressed air supply source to the air motor via a throttle valve operated via a throttle lever to drive the air motor. In the pneumatic tool, the throttle valve is housed in the valve housing that forms a main flow path for supplying compressed air supplied from a compressed air supply source to an air motor, and is slid by a throttle lever. The sleeve is operated to open and close the main flow path via a valve stem that is operated, and both ends of the guide sleeve that slidably accommodates both ends of the sleeve valve are exposed to the atmosphere. A sleeve valve that opens and shuts off the main flow path. An effective cross-sectional area difference in which compressed air acts is formed between the attached first seal member and the second seal member disposed in the guide sleeve, and the action of the compressed air acting on the portion of the effective cross-sectional area difference A throttle valve for a compressed air tool, wherein a sleeve valve is pressed in a direction to close the main flow path. An end portion side of the guide sleeve accommodating one end side of the sleeve valve is opened to the outer surface of the housing, one end is communicated with the outer surface of the housing and the other end is separated from the outer surface of the housing. 2. The compression according to claim 1, wherein a concave groove opened in the portion is formed, the outer surface of the housing is covered with a grip cover, and an exhaust passage is formed between the grip cover and the outer surface of the housing. Pneumatic tool throttle valve.

Images