JP6540235B2 - Driving machine - Google Patents

Description

  The present invention relates to the structure of a driving machine for driving a fastener member using compressed air (high pressure gas).

  There is known a driving machine which uses compressed air (high pressure gas) as a power source and drives a fastener member (nail, screw or the like) engaged with a plate material such as wood, gypsum board, steel plate or the like. In a nailing machine, an operation is performed to drive a nail in one direction with a strong driving force, and in a screwing machine, a screw is similarly driven for a distance shorter than the total screw length, and then it is rotated and tightened. The action is taken.

  The compressed air can be, for example, one generated by a compressor or the like and stored in a tank. Therefore, in such a driving machine, an air plug provided with an air hose for supplying compressed air is provided, and the driving machine is used in a state where the air hose is mounted on the air plug. In a driving machine, a driver blade is attached to a piston moved by compressed air. The piston is provided inside a cylinder having a cylindrical inner surface and is slidable between a top dead center and a bottom dead center. When a trigger (trigger lever) or the like attached to the driving machine main body is operated, compressed air is introduced into the piston upper chamber, which is a space formed above the piston in the cylinder, and under the piston in the cylinder. The air in the lower piston chamber, which is a space formed on the side, is released to lower the piston and the driver blade, and the lower end of the driver blade drives the fastener member to a predetermined length. In a screw driver, the fastener member is then tightened as the driver blade is rotated by the air motor. After the operation for driving the fastener member in the nailing machine or the fastening operation for the fastener member in the screwing machine is completed, the supply of the compressed air to the piston upper chamber is stopped and the compressed air therein is released, and the piston The piston is raised from the bottom dead center to the top dead center by introducing the compressed air into the lower chamber. Thereafter, the above-described driving operation can be performed again.

  In such a driving machine, the operation of the piston and the air motor described above is performed using compressed air supplied from an air hose (external), and the supplied compressed air is stored in an accumulator chamber provided inside the driving machine. After being stored, it is sent to each part to perform the above operation. In order to control this flow in the above operation, a plurality of valves are provided, and this compressed air is also used in the opening and closing operation of the valves. For example, the on / off operation of supplying compressed air to the piston upper chamber is controlled by the opening and closing operation of the main valve mounted on the cylinder, and the opening and closing operation of the main valve is also performed using the flow of compressed air. In the technology described in Patent Document 1, the opening and closing operation is performed by the vertical movement of the main valve, and the open and closed states of the main valve are the pressure of air in the main valve chamber provided above the main valve. Defined in When compressed air is introduced into the main valve chamber (the pressure in the main valve chamber is high), the main valve is closed at the lower side, and the main valve chamber communicates with the atmosphere (the main valve chamber When the pressure is low, the main valve is opened and opened to introduce compressed air into the piston upper chamber. Therefore, the main valve chamber is made to communicate with the atmosphere (the compressed air flows out from the main valve chamber), the main valve is opened (on operation), and the compressed air flows into the main valve chamber. A trigger valve is used to perform an operation (off operation) to close the switch. The on / off of the trigger valve is controlled by the operator operating a trigger (trigger lever) or the like.

  For example, when performing a continuous striking operation in which the striking operation is repeated at short time intervals, the trigger valve is repeatedly turned on and off at short time intervals, so the response speed of the opening / closing operation of the main valve at this time is fast. It is necessary to In the technology described in Patent Document 1, the response speed of the opening and closing operation of the main valve is enhanced by devising the configuration in which the trigger valve and the main valve chamber are combined, and the consumption of compressed air used at this time Is reduced. Such a configuration makes it possible in particular to perform the continuous striking operation stably.

JP 2005-262381 A

  At the end of one driving operation, after the operation to close the main valve from the open state (operation to stop the supply of compressed air to the piston upper chamber) is performed, the piston moves to the top dead center side. After that, the next driving operation can be performed. Here, particularly in the case of the continuous striking operation, when the timing of the operation of changing the main valve from the open state to the closed state is too fast, before the piston moves to the bottom dead center side, that is, one striking operation. In some cases, the introduction of compressed air to the piston upper chamber may stop before the operation is completely completed, and in this case, the driving operation may not be properly performed.

  In addition, in the screw driving machine, immediately after the driving operation, a tightening operation is performed to drive the air motor to rotate the screw. On the other hand, if the main valve is closed before the piston moves to the bottom dead center side as described above, the start timing of the tightening operation becomes inadequate, and the tightening operation is properly performed. There was a problem that I could not do it.

  On the other hand, in order to perform the continuous striking operation at a particularly short time interval, it has been required that the start of the striking operation (the operation of opening the main valve from the closed state) be performed promptly. For this reason, in the opening and closing operation of the main valve, the speed of the operation of changing the main valve from the closing state to the opening state is not equal to the speed of the operation of changing the main valve from the opening state to the closing state. Was requested. On the other hand, in the technique described in Patent Document 1, the speed of the operation of opening the main valve from the closing state and the speed of the operation of closing the main valve from the opening state are both equal to each other. When the driving operation is performed at short intervals, the driving operation may not be properly performed.

  That is, in the case of a driving machine driven by compressed air, when the driving operation is repeatedly performed at short intervals, it is difficult to stably perform the driving operation properly.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide an invention which solves the above problems.

The present invention has the following configuration in order to solve the above-mentioned problems.
The driving machine according to the present invention is provided by a pressure storage chamber provided in a housing, in which compressed air is stored, a piston provided movably in the vertical direction in the housing, and the piston in the housing. A piston upper chamber which is a space defined on the upper side of the piston, an open state for supplying compressed air from the pressure accumulation chamber to the piston upper chamber, and compressed air from the pressure accumulation chamber to the piston upper chamber The main valve is set according to the pressure of the air in the main valve chamber provided adjacent to the main valve chamber, and the switching between the open state and the closed state is controlled from the pressure accumulation chamber. A trigger valve for switching between an operation of flowing compressed air into the main valve chamber and an operation of discharging compressed air in the main valve chamber; A driving machine to perform the driving operation of the stopper member by the movement of the lower side of the piston by the compressed air in tons upper chamber is introduced, and the path of the inflow and outflow of compressed air in the main valve chamber A plurality of main valve control passages are provided, and when the main valve is changed from the closed state to the open state, outflow or inflow of compressed air to the main valve chamber is caused through all of the plurality of main valve control passages. When the main valve is switched from the open state to the closed state, the inflow of compressed air to the main valve chamber through the main valve control passage of a part of the plurality of main valve control passages It is characterized in that the outflow is suppressed.
In the driving machine according to the present invention, the part of the main valve control passage is configured to be closed by the main valve when the main valve is brought into the open state.
In the driving machine according to the present invention, a cylinder provided so that the piston slides inside and the piston upper chamber is formed on the piston is provided adjacent to the pressure accumulation chamber, and the main valve In the open state, compressed air is supplied from the pressure accumulation chamber to the piston upper chamber by separating the upper portion of the cylinder from the main valve, and in the closed state, the upper portion of the cylinder and the main valve And the main valve chamber is formed above the main valve in the housing so that the main valve chamber contacts the main valve chamber, and the main valve chamber is closed when the pressure in the main valve chamber is high. It is characterized in that the open state is made when the pressure in the chamber is low.
In the driving machine according to the present invention, the plurality of main valve control passages are connected to different portions in the vertical direction with respect to the main valve chamber, and the part of the main valve control passages is connected to the plurality of main valve controls Among the passages, the main valve control passage is connected below the main valve chamber.
In the driving machine according to the present invention, in the open state, the main valve control passages other than the part of the plurality of main valve control passages communicate with the main valve chamber, and the part of the main valve control passages The space between the valve and the main valve chamber is sealed by an elastic body.
In the driving machine of the present invention, the elastic body is an O-ring attached to the main valve.
The driving machine according to the present invention is provided by a pressure storage chamber provided in a housing, in which compressed air is stored, a piston provided movably in the vertical direction in the housing, and the piston in the housing. A piston upper chamber which is a space defined on the upper side of the piston, an open state for supplying compressed air from the pressure accumulation chamber to the piston upper chamber, and compressed air from the pressure accumulation chamber to the piston upper chamber The main valve is set according to the pressure of the air in the main valve chamber provided adjacent to the main valve chamber, and the switching between the open state and the closed state is controlled from the pressure accumulation chamber. A trigger valve for switching between an operation of flowing compressed air into the main valve chamber and an operation of discharging compressed air in the main valve chamber; It is a driving machine which performs driving operation of a fastener member by movement to the down side of said piston by introducing compressed air into a ton chamber, and when making said main valve said opening state from said closed state The flow passage area of the flow passage of the outflow or inflow of the compressed air to the main valve chamber is the flow of the flow passage of the inflow or outflow of the compressed air to the main valve chamber when the main valve is switched from the open state to the closed state. It is characterized by being larger than the road area.

  Since the present invention is configured as described above, when the driving operation is repeated at short intervals, the driving operation can be stably and properly performed.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the whole structure of the driving machine used as embodiment of this invention. It is sectional drawing (the 1) which shows the state of operation | movement of the main valve in the driving machine used as embodiment of this invention. It is sectional drawing (the 2) which shows the state of operation | movement of the main valve in the driving machine used as embodiment of this invention. It is sectional drawing which shows the structure of the main valve periphery in the modification of the driving machine used as embodiment of this invention.

  The configuration of a driving machine according to an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing the entire configuration of a driving machine 1. The fastener member is driven into a plate or the like placed on the lower side (a member to be fastened) by the driving machine 1, and FIG. 1 shows a cross-sectional view along an axial direction in which the fastener member is driven. . Here, the driving direction is the vertical direction. The up-down direction and the front-rear direction shown in the figure correspond to the direction viewed from the operator during normal operation.

  In this driving machine 1, the driving operation is performed by applying a driving force downward to the fastener member in the substantially cylindrical housing 10 whose central axis is the driving direction (vertical direction). A mechanism is provided. As a power source of this operation, compressed air supplied from the outside is used. In addition, the operation of a valve that controls the flow of compressed air for performing this operation is also performed using this compressed air.

  At the rear of the housing 10, a handle 60 which extends rearward and is held by an operator is fixed. At the rear end (right end in FIG. 1) of the handle 60, an air plug 61 for mounting an air hose (not shown) for supplying compressed air from the outside is fixed. Compressed air supplied via the air plug 61 is stored in a pressure storage chamber 62 provided from the handle 60 to the housing 10, and is flowed to each part in the housing 10 to be used for various operations. A pressure reducing valve may be provided in the air path between the air plug 61 and the pressure accumulation chamber 62 to adjust the pressure of the compressed air supplied from the air hose. In addition, it is necessary to discharge compressed air after being used for operation in the housing 10 to the outside, and an exhaust passage (not shown) serving as a passage for this purpose is also separated from the pressure storage chamber 62 in the handle 60 It is provided. The compressed air having passed through the exhaust passage is exhausted to the outside from an exhaust port provided at the end of the handle 60.

  In the housing 10, a cylinder 11 having a cylindrical inner surface whose central axis is in the vertical direction is provided, in which the piston 12 is provided slidably in the vertical direction between the top dead center and the bottom dead center. Be A driver blade 13 extending in the vertical direction is fixed to the lower surface side of the piston 12, and when the piston 12 moves downward, a lower end of the driver blade 13 causes a stopper member (not shown) to be subjected to a large impact force. It is driven toward the lower side. In FIG. 1, the piston 12 is located at the top dead center. On the other hand, on the lower side of the cylinder 11, a bumper 14 is provided which locks the piston 12 at the bottom dead center during the driving operation and absorbs the impact energy.

  During the driving operation, the lower end portion of the driver blade 13 moves inside the nose 15 projecting downward from the housing 10. On the other hand, a magazine 70 capable of storing a large number of fastener members is fixed to the nose 15, and when the driving operation is performed, one fastener member is loaded from the magazine 70 into the nose 15 one by one. Ru. By moving the driver blade 13 downward from the upper side with the fastener member loaded in the inside of the nose 15, the fastener member is driven downward from the injection port (not shown) at the lower end of the nose 15 Be Further, on the lower end side of the nose 15, a push lever 16 movable in the vertical direction along the nose 15 is mounted. The push lever 16 is biased downward by a spring (not shown), and protrudes downward below the injection port when no external force is applied.

  The driving operation is performed by the piston 12 being driven downward from the top dead center (the state of FIG. 1) by the compressed air. This operation will be described. This operation is started by the operator pulling the trigger (trigger lever) 63 provided on the lower side near the connection portion of the handle 60 with the housing 10 upward, and the push lever 16 moving upward. Here, the push lever 16 moves upward along the nose 15 by bringing the lower end side of the nose 15 into contact with the member to be fastened to which the fastener member should be driven. Therefore, the driver can perform the driving operation by pulling the trigger 63 upward while the operator brings the lower end side of the nose 15 into contact with the member to be fastened. Alternatively, in a state where the operator pulls the trigger 63, the driving operation can be performed by bringing the lower end side of the nose 15 into contact with the member to be fastened. In the latter case, while the operator pulls the trigger 63, the lower end side of the nose 15 is brought into contact with the member to be fastened to perform a continuous striking operation to repeat the operation of striking the fastener member. it can.

  In order to perform this operation, a trigger valve 20 operated by the movement of the trigger 63 and the push lever 16 as described above is provided on the top of the trigger 63. In the housing 10, a main valve 30 whose opening and closing operation is controlled by the trigger valve 20 is provided at the upper part of the cylinder 11. In the open state of the main valve 30 (the state in which the main valve 30 moves upward in FIG. 1), compressed air flows from the pressure accumulation chamber 62 around the cylinder 11 through the upper portion of the cylinder 11 to the upper side of the piston 12 in the cylinder 11 Is introduced into the piston upper chamber 11A which is a space of Since the O-ring 12A is mounted around the piston 12, the airtightness between the piston lower chamber 11B and the piston upper chamber 11A, which is the space under the piston 12 in the cylinder 11, is secured. On the other hand, when the main valve 30 is closed (the main valve 30 is moved downward), the main valve 30 seals the space between the piston upper chamber 11A and the pressure accumulation chamber 62. The operation of the main valve 30 is determined by the pressure in the main valve chamber 10A provided on the upper side of the main valve 30 in the housing 10, that is, whether or not compressed air is introduced into the main valve chamber 10A. When the trigger valve 20 is turned on, the main valve chamber 10A is in communication with the atmosphere, and the compressed air therein is discharged. On the other hand, when the trigger valve 20 is off, the main valve chamber 10A communicates with the pressure accumulation chamber 62, and compressed air is supplied to the main valve chamber 10A. The flow of such compressed air is performed via the main valve control passage 21 which causes the main valve chamber 10A and the trigger valve 20 to communicate with each other. As described later, the main valve control passage 21 is branched into two, that is, a first main valve control passage 21A and a second main valve control passage 21B on the side of the main valve chamber 10A.

  The driving operation is started by switching the trigger valve 20 from the off state to the on state. When the piston 12 descends during the driving operation, the air in the piston lower chamber 11B flows to the return air chamber 10B formed around the cylinder 11 on the lower side of the cylinder 11, and the piston 12 moves to the bottom dead center Thus, the fastener member is driven. Thereafter, the trigger 63 is returned downward, or the push lever 16 is moved downward to turn off the trigger valve 20, whereby the main valve 30 is closed, and the compressed air to the piston upper chamber 11A is obtained. Supply stops. Thereafter, the compressed air stored in the return air chamber 10B flows to the piston lower chamber 11B and the compressed air in the piston upper chamber 11A is discharged, so that the piston 12 moves to the top dead center again. Thereafter, when the trigger valve 20 is turned on again, the driving operation is performed again.

  The above configuration is the same as that of the driving machine described in Patent Document 1. However, this driving machine 1 is characterized in control of the open / close state of the main valve 30 by the trigger valve 20. Below, this point is explained.

  2 and 3 show the structure relating to the main valve 30 in the driving machine 1 when the main valve 30 is closed (FIG. 2 (a), and transition from the closed state to the open state (FIG. 2 (b)), 3 (c) and at the time of transition from the open state to the closed state (FIG. 3 (d)), in which the periphery of the main valve 30 in FIG. Here, as shown in FIG. 1, the main valve control passage 21 for communicating the trigger valve 20 with the main valve chamber 10A is the first main valve control passage on the main valve chamber 10A side. The first main valve control passage 21A and the second main valve control passage 21B are shown in FIGS.

  As shown in FIG. 2 (a), the main valve 30 has a main valve main body 31 which has a substantially cylindrical shape corresponding to the cylinder 11 and is provided above the cylinder 11, and around the cylinder 11 (FIG. A pressure accumulation chamber 62 is provided on the left and right sides in a). At the lower end of the main valve main body 31, a main valve rubber 32 which is mounted so as to be able to seal the upper end of the cylinder 11 and which is elastically deformable is mounted. In FIG. 2A, since the main valve 30 is located on the lower side and the main valve rubber 32 seals the upper end of the cylinder 11, the piston upper chamber 11A and the pressure accumulation chamber 62 are not communicated. 2A and the like, a cross section taken along the central axis X of the cylinder 11 is shown, and the piston 20 and the main valve 30 have symmetrical shapes around the central axis X.

  The main valve 30 is a housing such that the main valve chamber 10A is formed between the main valve chamber defining portion 101, which is a part of the upper side of the housing 10 in the state of FIG. 10 will be installed. The volume of the main valve chamber 10A fluctuates depending on the position of the main valve 30 in the vertical direction. The first main valve control passage 21A and the second main valve control passage 21B are connected to places of different heights in the main valve chamber 10A (main valve chamber defining portion 101), and the first main valve control passage 21A is The first main valve control passage connection portion 101A and the second main valve control passage 21B located on the upper side are connected to the main valve chamber defining portion 101 at the second main valve control passage connection portion 101B located on the lower side. ing. The first main valve control passage connection portion 101A is provided near the top of the main valve chamber 10A.

  Further, an O-ring 33A is mounted on the inner peripheral side of the main valve main body 31, and O-rings 33B (upper side) and 33C (lower side) are mounted on the outer peripheral side, thereby forming the main valve body 31 and the main valve chamber. The portion between the portion 101 and the portion 101 is sealed. The O-rings 33A, 33B, 33C are made of an elastic material, and each of the O-rings 33A, 33B, 33C winds the main valve body 31 around the central axis X. Therefore, the flow of the compressed air of the main valve chamber 10A through the portions other than the first main valve control passage 21A and the second main valve control passage 21B communicated with the main valve chamber 10A is suppressed, and the main valve chamber 10A is The compressed air (pressure) is controlled using the first main valve control passage 21A and the second main valve control passage 21B.

  Further, in the main valve chamber 10A, a main valve spring 34 which is a spring configured to wind the main valve main body 31 is provided. The upper end of the main valve spring 34 is engaged with the inner surface of the upper main valve chamber defining part 101 in the main valve chamber 10A, and the lower end of the main valve spring 34 is engaged with the lower main valve body 31 in the main valve chamber 10A. It is stopped. Therefore, the main valve 30 (main valve main body 31) is biased by the main valve spring 34 to the lower side, that is, to the side where the main valve 30 is closed.

  On the other hand, in a state in which the compressed air is introduced into the main valve chamber 10A, the main valve 30 receives a downward pressure from the compressed air in the main valve chamber 10A. In addition, the main valve 30 also receives upward pressure from the compressed air in the pressure accumulation chamber 62 through the main valve rubber 32. Further, the downward elastic force applied to the main valve 30 by the main valve spring 34 is smaller than the upward pressure received by the compressed air in the pressure accumulation chamber 62 through the main valve rubber 32. It is set.

  In the state shown in FIG. 2A, the O ring 33B mounted on the upper side of the outer periphery of the main valve body 31 is closer than the second main valve control passage connection portion 101B which is the lower inlet of compressed air to the main valve chamber 10A. It is located further down. Therefore, the first main valve control passage connection portion 101A and the second main valve control passage connection portion 101B both communicate with the main valve chamber 10A. Therefore, compressed air can be supplied from the trigger valve 20 into the main valve chamber 10A via both the first main valve control passage 21A and the second main valve control passage 21B. Thereby, the high pressure in the main valve chamber 10A can be maintained. Further, in the state of FIG. 2A in which the compressed air is introduced into the main valve chamber 10A, the main valve 30 is biased to the lower side, that is, the side to be closed, so the main valve chamber 10A The closed state is maintained as long as the internal pressure is maintained, and the piston 12 does not move from the top dead center.

  On the other hand, FIG. 2 (b) shows a state immediately after the trigger valve 20 is turned on. In this case, the main valve control passage 21 (the first main valve control passage 21A, the second main valve control passage 21B) is switched by the trigger valve 20 so as to communicate with the atmosphere. Therefore, the compressed air in the main valve chamber 10A is discharged through the first main valve control passage 21A and the second main valve control passage 21B, and the pressure in the main valve chamber 10A is reduced. Here, since the elastic force of the main valve spring 34 is smaller than the upward pressure that the main valve 30 receives by the compressed air in the pressure accumulation chamber 62 via the main valve rubber 32, the main valve 30 rises. Thereby, a gap is formed between the main valve rubber 32 and the upper end portion of the cylinder 11, and compressed air is introduced from the pressure accumulation chamber 62 to the piston upper chamber 11A through the gap, and the piston 12 is lowered by the pressure. Do. Thus, the driving operation is started. In the state of FIG. 2 (b), the state immediately after the main valve 30 has started to rise is shown.

  FIG. 3C shows a state in which the main valve 30 is further raised and positioned at the top (fully open state). In this case, since the upper end portion of the main valve body 31 is locked to the inner surface of the upper main valve chamber defining portion 101 in the main valve chamber 10A, the main valve 30 is positioned at the top. For this reason, in FIG. 3C, the main valve 30 is shown in a fully opened state, and in this state, compressed air is introduced into the piston upper chamber 11A at a large flow rate.

  In this state, since the main valve 30 is further raised above the state shown in FIG. 2B, the upper O ring 33B is an outlet below the compressed air with respect to the main valve chamber 10A. It moves above the main valve control passage connection part 101B. Therefore, in this state, the lower second main valve control passage connection portion 101 B is closed by the main valve main body 31. Thus, the state in which the main valve 30 is fully open is maintained until the driving operation is finished (the piston 12 moves to the bottom dead center).

  FIG. 3D shows a state immediately after the trigger valve 20 is turned off again after the piston 12 has moved to the bottom dead center. In this case, in order to supply the compressed air to the main valve chamber 10A, the compressed air is supplied to the main valve control passage 21. The compressed air is branched and supplied to both the first main valve control passage 21A and the second main valve control passage 21B. In this state, as described above, the lower second main valve control passage connection portion Since the block 101B is closed, the second main valve control passage 21B does not function as a path for supplying compressed air to the main valve chamber 10A. Therefore, compressed air is supplied into the main valve chamber 10A only through the first main valve control passage 21A and the first main valve control passage connection portion 101A located on the upper side.

  As a result, the pressure in the main valve chamber 10A increases to lower the main valve 30, and finally, as in FIG. 2A, the main valve 30 is fully closed, and the piston upper chamber 10A is The supply of compressed air is stopped. As described above, in this state, since the main valve 30 moves downward, the lower second main valve control passage connection portion 101B and the main valve chamber 10A communicate again, and the first main valve control passage 21A, Compressed air is supplied to the main valve chamber 10A from both of the second main valve control passages 21B.

  Thereafter, the compressed air stored in the return air chamber 10B in FIG. 1 flows to the piston lower chamber 11B, and the compressed air in the piston upper chamber 11A is discharged and the piston 12 moves again to the top dead center side. It becomes the state of 2 (a). The configuration in which compressed air flows from the return air chamber 10B to the lower piston chamber 11B and from the upper piston chamber 11A to the atmosphere is the same as that described in Patent Document 1, for example, and the present invention is essentially Description is omitted because it is irrelevant.

  In the above operation, when the main valve 30 is opened from the closed state (when transitioning from FIG. 2A to FIG. 2B), the compressed air in the main valve chamber 10A is discharged. As a path, both of the first main valve control passage 21A and the second main valve control passage 21B were used. By this, it is possible to increase the speed at which the compressed air in the main valve chamber 10A flows out (for example, the flow rate of air per second). That is, the response speed at the time of opening the main valve 30 from the closed state can be increased.

  On the other hand, when the main valve 30 is switched from the open state to the closed state (when transitioning from FIG. 3 (c) to FIG. 3 (d)), as a path for supplying compressed air into the main valve chamber 10A, Only the first main valve control passage 21A is used, and the second main valve control passage 21B is not used. For this reason, the inflow rate of compressed air (for example, the inflow of air per second) into the main valve chamber 10A is limited to a value determined by the first main valve control passage 21A, and at least compression into the main valve chamber 10A is performed. The flow rate is reduced compared to the inflow speed when both the first main valve control passage 21A and the second main valve control passage 21B are used as a path for supplying air. That is, the response speed when the main valve 30 is closed from the open state can be limited.

  Here, when both of the first main valve control passage 21A and the second main valve control passage 21B are used as a path for supplying compressed air into the main valve chamber 10A, the inflow velocity of the compressed air is the first main valve control It is determined by the cross sectional area of the passage 21A and the second main valve control passage 21B, and both the first main valve control passage 21A and the second main valve control passage 21B are used as a passage for discharging the compressed air in the main valve chamber 10A. Is equivalent to the outflow rate of compressed air. Therefore, in the above configuration, the outflow velocity of the compressed air to the main valve chamber 10A when the main valve 30 is opened from the closed state is the main valve chamber when the main valve 30 is closed from the open state It becomes larger than the inflow velocity of compressed air to 10A.

  Therefore, with the above configuration, the response speed at the time of opening the main valve 30 from the closed state is increased to improve the response at the start of the striking operation, and the timing at which the main valve 30 is closed from the open state Can be suppressed, for example, the main valve 30 can not be closed before the driving operation is completed. Thereby, for example, the continuous striking operation can be stably performed.

  Further, the above configuration branches the main valve control passage 21 into two, the first main valve control passage 21A and the second main valve control passage 21B on the main valve chamber 10A side, and these are connected to the main valve chamber 10A This is realized by providing the first main valve control passage connection portion 101A and the second main valve control passage connection portion 101B, which are portions, at different locations along the moving direction (vertical direction) of the main valve 30. For this reason, the driving machine 1 having the above-described function can be manufactured at low cost.

  In the above configuration, the inner diameters (the cross-sectional areas in the direction in which the compressed air flows) of the first main valve control passage 21A and the second main valve control passage 21B do not have to be equal. The flow rate of compressed air from the main valve chamber 10A when the main valve 30 is opened from the closed state by adjusting each inner diameter, and the main valve when the main valve 30 is closed from the open state The ratio to the inflow velocity of the compressed air into the chamber 10A can be adjusted. Thus, it is possible to adjust the ratio of the response speed when the main valve 30 is opened from the closed state to the response speed when the main valve 30 is closed from the open state. For example, the response speed when the main valve 30 is switched from the closed state to the open state can be increased when the main valve 30 is switched from the open state to the closed state by relatively increasing the inner diameter of the second main valve control passage 21B. The ratio to response speed can be larger.

  The same function as the above can also be realized by a main valve having another structure. Here, in order to speed up the response speed when the main valve is opened from the closed state, for example, the sliding resistance when the main valve slides on the inner surface of the main valve chamber defining portion 101 is reduced. Is valid. In addition, in order to stably perform the above operation, it is required to ensure the airtightness (sealability) of the main valve chamber 10A, and in the above example, the airtightness is an O-ring 33A which is an elastic body. , 33B, 33C. Other configurations can be used to enhance this tightness. The air tightness is also related to the air tightness to the second main valve control passage 21B when the second main valve control passage connection portion 101B is closed when the main valve is in the open state.

  The structure of the modification of the above-mentioned driving machine 1 in consideration of these points will be described. FIG. 4 (a) is a cross-sectional view showing a structure of the first modification, corresponding to FIG. 3 (c). The upper O-ring 33B is not attached to the main valve body 41 of the main valve 40 used here. Also in this case, since the lower O-ring 33C and the inner O-ring 33A are provided in the same manner as the structure of FIG. 2, the airtightness of the main valve chamber 10A is secured. In this case, since the O-ring 33B is not provided, the space between the lower second main valve control passage connection portion 101B and the upper main valve chamber 10A is not sealed, and the second main valve control passage 21B is interposed. The flow of compressed air to the main valve chamber 10A is not completely shut off. However, if the gap between the outer peripheral surface of the main valve main body 41 and the inner surface of the main valve chamber defining portion 101 is small, the flow rate of the compressed air flowing through this gap is the upper first main valve control passage connection portion 101A. It can be negligibly small compared to the flow rate flowing through it. Therefore, the same effect as described above is obtained.

  In this case, the number of O-rings, which is a resistance when the main valve 40 slides on the inner surface of the main valve chamber defining part 101, is smaller than in the configuration of FIGS. Can be performed more smoothly, and the response speed at the time of switching from the closed state to the open state can be further improved. Moreover, since the structure of the main valve 40 can be made simpler and the number of parts can be reduced, the driving machine can be made cheaper.

  FIG. 4B is a cross-sectional view similarly showing the configuration of the second modified example. An O-ring 33A is provided on the inner side of the main valve body 51 of the main valve 50 used in this case, as in the configuration of FIG. However, no O-ring is provided on the outside of the main valve main body 51, and instead, a rubber ring (elastic member) 52 having a larger spread in the vertical direction than the O-ring is attached to the outer periphery of the main valve main body 51 ing. This structure is equivalent to the structure in which the O-ring 33B and the O-ring 33C in the structure of FIG. 2 are vertically connected. In this case, the air tightness of the main valve chamber 10A and the air tightness to the second main valve control passage 21B when the main valve 50 is in the open state are enhanced by the rubber ring 52 than the structure of FIG. The same is true for the reduction in the number of parts.

  In addition, when the main valve is opened (the main valve is on the upper side), only the second main valve control passage connection portion 101B (the second main valve control passage 21B) is closed by the main valve main body. If it is, the main valve of another structure can be used.

  In the above configuration, the main valve 30 is in the closed state when it is located on the lower side and in the open state when it is located on the upper side, but the correspondence relationship between the position of the main valve and the closed state, the open state is The setting can be made appropriately according to the configuration of the driving machine, for example, the configuration of the cylinder and the main valve. It is apparent that a configuration similar to that described above is possible, even if this setting is different from that described above.

  In the above example, the main valve 30 is closed when the pressure in the main valve chamber 10A is high, and is opened when the pressure in the main valve chamber 10A is low. The correspondence relationship between the state and the open state can be appropriately set according to the configuration of the driving machine. In the above example, the outflow speed of the compressed air from the main valve chamber when the main valve is opened from the closed state is the inflow of the compressed air into the main valve chamber when the main valve is closed from the open state It was faster than speed. On the other hand, conversely to the above, when the pressure in the main valve chamber is low, the valve is closed, and when it is high, the valve is opened. If the inflow velocity of the compressed air is set to be larger than the outflow velocity of the compressed air from the main valve chamber when the main valve is closed from the open state, the same effect is achieved. Also in this case, one of the main valve control passages may be connected to a portion closed by the main valve when the main valve is in the open state.

  Further, in the above example, when the main valve control passage 21 is branched into two and the main valve 30 is opened, one of the connection points to the main valve chamber 10A (second main valve control passage The connection portion 101B) is configured to be closed. However, the main valve control passage may be branched into three or more, and one of the connection points may be closed when the main valve is opened. Alternatively, all connection points other than one of the connection points may be closed. With this setting, as in the case of adjusting the inner diameters of the first main valve control passage 21A and the second main valve control passage 21B described above, the response speed when the main valve is opened from the closed state, and the main valve The ratio of the response speed at the time of switching from the open state to the closed state can be adjusted.

  Further, in the above configuration, when the main valve control passage 21 is branched and the number of passages after branched used as compressed air passages is changed from the closed state to the open state, from the open state to the closed state It was configured to switch between cases. Varying the number of passages used is equivalent to changing the passage cross-sectional area of the passage (the cross-sectional area perpendicular to the direction in which the compressed air flows). Therefore, even if the flow passage cross-sectional area in the case of changing from the closed state to the open state is larger than the flow passage cross-sectional area in the case of changing from the open state to the closed state by another method, the same applies. Play an effect.

  Moreover, although the above-mentioned example was the driving machine which drives in a fastener member, the same structure should be applied to a screw driving machine as long as the main valve which controls the flow of compressed air is similarly used. You can also. Also in this case, if the timing at which the main valve changes from the open state to the closed state is too fast, the timing of the tightening operation performed after the driving operation deviates from the optimal timing, and the appropriate tightening operation can not be performed. Therefore, according to the above configuration, the screwing operation can be stably performed even in the screwing machine.

DESCRIPTION OF SYMBOLS 1 driving machine 10 housing 10A main valve chamber 10B return air chamber 11 cylinder 11A piston upper chamber 11B piston lower chamber 12 piston 12A O ring 13 driver blade 14 bumper 15 nose 16 push lever 20 trigger valve 21 main valve control passage 21A 1st Main valve control passage (main valve control passage)
21 B 2nd main valve control passage (main valve control passage)
30, 40, 50 Main valve 31, 41, 51 Main valve body (main valve)
32 Main valve rubber (main valve)
33A, 33B, 33C O-ring (elastic body)
34 Main valve spring 52 Rubber ring (elastic body)
60 handle 61 air plug 62 pressure accumulation chamber 63 trigger (trigger lever)
70 magazine 101 main valve chamber defining portion 101A first main valve control passage connecting portion 101B second main valve control passage connecting portion

Claims (7)

An accumulator chamber provided in the housing and having compressed air stored therein;
A piston movably provided in the vertical direction in the housing;
A piston upper chamber which is a space defined by the piston and formed on the upper side of the piston in the housing;
An open state in which compressed air is supplied from the pressure accumulation chamber to the piston upper chamber and a closed state in which the flow of compressed air from the pressure accumulation chamber to the piston upper chamber is set are set. A main valve whose switching is controlled according to the pressure of the air in the adjacent main valve chamber,
A trigger valve that switches between an operation of flowing compressed air from the pressure accumulation chamber into the main valve chamber and an operation of flowing out compressed air in the main valve chamber;
A driving device for driving a fastener member by moving downward of the piston by introducing compressed air into the upper chamber of the piston;
A plurality of main valve control passages are provided as paths of inflow and outflow of compressed air in the main valve chamber;
When the main valve is changed from the closed state to the open state, compressed air flows or flows into the main valve chamber through all of the plurality of main valve control passages.
When the main valve is switched from the open state to the closed state, inflow or outflow of compressed air to or from the main valve chamber via the main valve control passage of a part of the plurality of main valve control passages is suppressed A driving machine characterized in that it is configured . The driving machine according to claim 1 , wherein the part of the main valve control passage is closed by the main valve when the main valve is in the open state. A cylinder is provided adjacent to the pressure accumulation chamber, the cylinder being provided so that the piston slides inside and the piston upper chamber is formed on the piston,
The main valve supplies compressed air from the pressure accumulation chamber to the piston upper chamber by separating the upper portion of the cylinder and the main valve in the open state, and in the closed state, the main valve and the upper portion of the cylinder It is provided at the top of the cylinder so that it abuts on the main valve,
The main valve chamber is formed in the housing above the main valve.
The driving machine according to claim 2 , wherein the closed state is set when the pressure in the main valve chamber is high, and the open state is set when the pressure in the main valve chamber is low. The plurality of main valve control passages are connected to the main valve chamber at different points in the vertical direction,
The strike according to claim 3 , wherein the part of the main valve control passage is the main valve control passage connected below the main valve chamber among a plurality of the main valve control passages. Machine. In the open state, the main valve control passages other than the part among the plurality of main valve control passages communicate with the main valve chamber, and between the part of the main valve control passages and the main valve chamber The driving tool according to claim 4 , wherein the at least one elastic member is sealed with an elastic body. The driving machine according to claim 5 , wherein the elastic body is an O-ring attached to the main valve. An accumulator chamber provided in the housing and having compressed air stored therein;
A piston movably provided in the vertical direction in the housing;
A piston upper chamber which is a space defined by the piston and formed on the upper side of the piston in the housing;
An open state in which compressed air is supplied from the pressure accumulation chamber to the piston upper chamber and a closed state in which the flow of compressed air from the pressure accumulation chamber to the piston upper chamber is set are set. A main valve whose switching is controlled according to the pressure of the air in the adjacent main valve chamber,
A trigger valve that switches between an operation of flowing compressed air from the pressure accumulation chamber into the main valve chamber and an operation of flowing out compressed air in the main valve chamber;
A driving device for driving a fastener member by moving downward of the piston by introducing compressed air into the upper chamber of the piston;
The flow passage area of the flow path of the outflow or inflow of the compressed air to the main valve chamber when the main valve is changed from the closed state to the open state corresponds to when the main valve is changed from the open state to the closed state A driving tool characterized in that it is larger than a flow passage area of a flow passage of compressed air to or from the main valve chamber.

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