JP4241407B2 - Intermediate position stop cylinder - Google Patents

Description

  The present invention relates to a cylinder (fluid pressure cylinder) as an actuator that operates by a fluid pressure such as pneumatic pressure or hydraulic pressure, and in particular, not only can a piston moving inside the cylinder stop at two positions at both ends of the cylinder. Further, the present invention relates to an intermediate position stop cylinder which can be stopped even at an arbitrarily set intermediate 1 or 2 position.

  In a fluid pressure cylinder, such as a conventional air cylinder, the piston is pushed by the fluid pressure, moves through the cylinder, and arbitrarily stops except when it stops by touching either end of the cylinder. It was not possible to accurately stop the piston, and thus any driven part connected to the piston, at a defined intermediate position. In that sense, it can be said that conventional hydraulic cylinders, in particular air cylinders, are only "two-position stop cylinders". In general, it is often necessary to perform multi-point positioning of 3 or more points in processing equipment, but in such cases, an air cylinder cannot be used. There is a problem that it is necessary to use a servo motor or the like, which increases costs.

  In conventional air cylinders, in addition to both ends of the cylinder, an attempt has been made to incorporate a special brake into the cylinder in order to stop the piston and the driven part connected to it at an arbitrary position between them. Since the stop position by the brake is generally inaccurate, such means are used for limited applications, such as when high accuracy is not required for the stop position, or to prevent falling of the driven part. It was just something that could be done.

  The present invention solves such a problem in the prior art by adding a simple mechanism to the conventional hydraulic cylinder rather than a means with a significant increase in cost as in a servo motor. To provide a low-cost intermediate position stop cylinder that can stop the piston and the driven part connected to it at any one or two positions in between, in addition to the two positions at both ends. It is aimed.

  The present invention provides an intermediate position stop cylinder according to claim 1 in order to solve the above-mentioned problems.

The intermediate position stop cylinder of the present invention is characterized by the use of a three position valve to switch and supply pressurized fluid to two space portions formed on both sides of a piston in a hydraulic cylinder, and its valve spool. Between the driven part of the fluid pressure cylinder and the frame, when the valve spool is always urged to return to the neutral position to equalize the two space parts of the fluid pressure cylinder. In addition, a first spring device that provides a first intermediate position between a return position and an advanced position corresponding to both ends of the fluid pressure cylinder and a second spring device that provides a second intermediate position are provided. There are features.

When the intermediate position stop cylinder of the present invention includes both the first spring device and the second spring device, it can be accurately stopped at any two positions between the return position and the advance position. ing to be referred to as a "4-position stop cylinder".

  The first spring device is provided in the first rod so as to be in contact with the driven portion, and a first rod that is inserted into and supported by a hole formed in the frame and can move in parallel with the piston rod. A first spring that is mounted in a compressed state between the head and the frame and a first stopper that limits the movement range of the first rod can be used.

  The second spring device is attached to the driven portion in parallel with the piston rod, and can move while sliding in the sleeve attached to the frame, and slides on the sleeve. And a second spring mounted in a compressed state between the frame and the spring receiver, and a spring receiver capable of engaging with a head formed at the rear end of the second rod. The second stopper for limiting the movement range of the spring receiver can be configured.

  At least one of the first stopper and the second stopper can be constituted by a male screw portion and a nut screwed thereto. In this case, the stop position can be freely and smoothly changed and set by adjusting the screwing position of the nut on the male screw part.

  Specifically, a three-position valve having a pair of solenoids and a pair of springs at both ends of the valve spool can be used. In this case, both of the pair of springs can be compression springs.

  The intermediate position stop cylinder of the present invention is most suitable when the fluid pressure cylinder is an air cylinder.

  Hereinafter, as a preferred embodiment of the intermediate position stop cylinder of the present invention, a four-position stop air cylinder whose longitudinal cross-sectional configuration is shown in FIG. 1 will be described in detail. FIGS. 2 to 5 show the operating state of the four-position stop cylinder of the embodiment shown in FIG. 1, and correspond to the four stop positions, respectively.

  In FIG. 1, reference numeral 1 denotes an air cylinder, which is fixedly attached by a stay 2 to a frame of a target device (not shown) such as some processing apparatus. Therefore, the stay 2 is a part of the frame. A piston 3 is inserted inside the air cylinder 1 so as to be reciprocally slidable in the longitudinal direction while maintaining airtightness, and a piston rod 4 integrated with the piston 3 is located on the left side of the air cylinder 1. It penetrates the end wall 5 and the stay 2 and protrudes to the left. A seal 6 is provided at a portion where the piston rod 4 penetrates the end wall 5 of the air cylinder 1 to maintain airtightness. In this way, the internal space of the air cylinder 1 is divided into a left space 7 and a right space 8 by the piston 3. The left end wall 5 and the right end wall 9 of the air cylinder 1 are formed with recesses 10 and 11 having a radius smaller than that of the piston 3, and pipes 12 and 13 are connected to these recesses 10 and 11. The pipes 12 and 13 extend to a three-position valve 14 described later.

  An arm-like slider 15 extending in the vertical direction is attached to the left end portion of the piston rod 4 of the air cylinder 1. The slider 15 is a part of a driven portion that is driven and positioned by a four-position stop air cylinder including the air cylinder 1 and its accompanying portion. The slider 15 mechanically connects two spring devices provided below the air cylinder 1, that is, the first spring device 16 and the second spring device 17, and the piston rod 4 of the air cylinder 1, and connects them. In addition to being linked together, it is provided for mechanically connecting the piston rod 4 and a processing device (not shown).

  The first spring device 16 includes a rod 18 attached to the slider 15, and the rod 18 is slidably inserted into a hole 23 formed in the stay 2. The rod 18 is supported by the hole 23 so as to be parallel to the piston rod 4 of the air cylinder 1. A coiled compression spring having a predetermined spring constant is mounted as a first spring 19 between a flange-shaped head portion 49 formed at the front end of the rod 18 and the stay 2 so as to fit loosely into the rod 18. ing. In order to apply an initial compressive force of a predetermined magnitude to the first spring 19, a nut 21 is screwed into the male screw part 20 of the rod 18, and the adjusted screwing position of the nut 21 is also the male screw part 20. It is securely held by the lock nut 22 screwed into. In the illustrated embodiment, the rod 18 is supported by the stay 2 that is a part of the frame. However, as a modification, the rod 18 may be supported on the slider 15 side.

  The second spring device 17 includes a long rod 24 attached to the slider 15 at the left end. The rod 24 is also parallel to the piston rod 4 of the air cylinder 1. A part of the rod 24 is slidably inserted into the sleeve 25. The left end of the sleeve 25 is integrally attached to the stay 2. Further, a male screw portion 26 is formed at the right end portion of the sleeve 25, and a spring receiver 27 shaped like a cup is loosely inserted so that the sleeve can freely slide in the longitudinal direction. Yes. In order to adjust the position of the spring receiver 27 and to prevent the spring receiver 27 from slipping rightward from the end of the sleeve 25, a nut 28 is screwed into the male screw portion 26. Reference numeral 29 denotes a lock nut for the nut 28. A coiled compression spring having a predetermined spring constant is mounted as the second spring 30 so as to be loosely fitted to the sleeve 25 between the spring receiver 27 and the stay 2. A flange-shaped head portion 50 that can be engaged with the spring receiver 27 is formed at the rear end portion of the rod 24.

  In order to selectively supply compressed air to the left and right spaces 7 or 8 in the air cylinder 1 or to discharge air from these spaces, a three-position valve 14 for control is connected to the pipes 12 and 13. . As schematically shown in FIG. 1, the three-position valve 14 includes a valve spool 32 that can reciprocate in the left-right direction within the valve cylinder 31. Since compression springs 33 and 34 having equal characteristics are mounted on the left and right ends of the spool 32, the spool 32 is neutral as shown in FIG. 1 by the balance of the compression force of the springs 33 and 34. Always biased towards position. However, in the illustrated embodiment, a pair of compression springs 33 and 34 are used. However, a pair of compression springs 33 and 34 may be used as long as the spool 32 can be directed to the neutral position without necessarily using a pair of compression springs. Or a single coil spring or the like. When one coil spring is used, one end of the coil spring is directly attached to the spool 32, and the other end is attached to one end of the valve cylinder 31, so that both the compression force and the tensile force of the coil spring can be obtained. And when the spool 32 is in the neutral position, these forces are all zero.

  Solenoids (electromagnets) 35 and 36 capable of generating a biasing force larger than the biasing forces of the springs 33 and 34 that are equal to each other correspond to the left and right ends of the valve spool 32 in parallel with the springs 33 and 34. By being switched by a control device (not shown), power is selectively supplied from a power source (not shown) or the power supply is cut off. When one of the left and right solenoids 35 and 36 is supplied with electric power and is electrically energized, the spool 32 is moved to the other solenoid 35 or 36 against the energizing force of the spring 33 or 34 opposed thereto. It can be pressed toward. Accordingly, the valve spool 32 can selectively take a total of three positions, that is, a neutral position as shown in FIG. 1 and a position moved to the right and left. In a state after the spool 32 moves to the right or left, the left air passage portion 37 or the right air passage portion 38 occupies the position where the central air passage portion 39 was located in FIG. The solenoids 35 and 36 should generally be referred to as “drive means” of the valve, and are not necessarily provided in pairs.

  A supply port 40 is opened on the inner surface of the valve cylinder 31, for example, at the lower center in FIG. 1, and is connected by a pipe 42 to a compressed air supply source 41 such as a compressor and a compressed air tank. . Discharge ports 43 and 44 that are open to the atmosphere are opened so that the supply ports 40 are arranged on the left and right sides at a predetermined interval. In addition, two control ports 45 and 46 are opened at predetermined intervals at positions different from the ports 40, 43, 44 on the inner surface of the valve cylinder 31, for example, on the upper side in FIG. 12 and 13 communicate with the left and right spaces 7 and 8 of the air cylinder 1.

  As a preferred embodiment of the intermediate position stop cylinder of the present invention, the four-position stop air cylinder shown in FIG. 1 has such a configuration including the air cylinder 1 and its associated part. Four operating states as shown in FIG. The state shown in FIG. 1 is substantially the same as that shown in FIG.

  FIG. 2 shows a state where the piston 3 of the air cylinder 1 is in a “return position” which is one of four operating states in the four-position stop air cylinder of the embodiment shown in FIG. The fact that the piston 3 takes the return position means that the piston 3 is closest to the right end wall 9 which is the bottom surface of the air cylinder 1, so that the front surface which is the reference surface of the slider 15 is This is the state where it has reached the position of the return end 47 shown in FIG. In this state, the solenoid 35 on the left side of the three-position valve 14 is energized by a command from a control device (not shown), so that the valve spool 32 shown in FIG. 1 is moved to the right end of the movable range against the urging force of the right spring 34. This is realized by moving to a position. As a result, the left air passage portion 37 of the spool 32 comes to the central position of the valve cylinder 31, so that the compressed air supply source 41 communicates with the control port 45 by a passage provided in the left air passage portion 37 of the spool 32. Then, compressed air is supplied to the left space 7 of the air cylinder 1 through the pipe 12 to move the piston 3 to the right, while the air in the right space 8 of the piston 3 is moved to the pipe 13. In addition, the air is discharged into the atmosphere through a passage provided in the air passage portion 37 on the left side of the control port 46 and the spool 32.

  When the piston 3 of the air cylinder 1 takes the return position as shown in FIG. 2, the distance between the slider 15 and the stay 2 becomes the minimum value D <b> 1 by the slider 15 coming to the return end 47. In this state, the first spring 19 constituting the first spring device 16 is compressed most strongly, so that a gap of L1 is generated between the rear end surface of the stay 2 and the nut 21. The second spring 30 constituting the second spring device 17 extends the longest.

  FIG. 3 shows a state where the piston 3 of the four-position stop air cylinder shown in FIG. 1 is in the “advance position” among the four operating states. The piston 3 takes the forward position when the piston 3 is closest to the left end wall 5 that is the front end surface of the air cylinder 1 and the front surface that is the reference surface of the slider 15 is illustrated in FIG. 3 is a state in which it has reached the position of the forward end 48 shown in FIG. In this state, the solenoid 36 on the right side of the three-position valve 14 is energized according to a command from a control device (not shown) to move the valve spool 32 to the left end position in the movable range against the urging force of the left spring 33. It is realized by. As a result, the air passage portion 38 on the right side of the spool 32 comes to the center position of the valve cylinder 31, so that the compressed air supply source 41 communicates with the control port 46 through the passage provided in the right air passage portion 38 of the spool 32. The compressed air is supplied to the space 8 on the right side of the piston 3 through the pipe 13 to move the piston 3 to the left, while the air in the space 7 on the left side of the piston 3 is moved to the pipe 12 and the control port 45. And is released into the atmosphere through a passage provided in the air passage portion 38 on the right side of the spool 32.

  When the piston 3 takes the forward position in the air cylinder 1, the slider 15 reaches the forward end 48 shown in FIG. 3, and the distance between the slider 15 and the stay 2 becomes the maximum value D4. In this state, the first spring 19 extends the longest, but when the nut 21 screwed into the male screw portion 20 of the rod 18 constituting the first spring device 16 comes into contact with the rear end surface of the stay 2, the rod is further increased. Since the 18 cannot move forward with respect to the nut 21, the first spring 19 supported at the front end by the head 49 at the front end of the rod 18 cannot extend further. In addition, the second spring 30 provided in the second spring device 17 is configured such that the head 50 at the rear end of the rod 24 engages with the spring receiver 27 in order for the slider 15 to move away from the stay 2 to the maximum extent. Then, it is moved forward from the nut 28 by a distance L1. Accordingly, the second spring 30 is compressed.

  The first spring device 16 and the second spring device 17 in the illustrated embodiment show the features of the present invention, but even a conventional air cylinder that does not have such a configuration unique to the present invention has 2 By using a position valve or the like, it is possible to realize substantially only two of the return position and the advance position. However, an arbitrary intermediate position between the return end 47 and the forward end 48, such as a first intermediate position 51 described with reference to FIG. 4 and a second intermediate position 52 described with reference to FIG. In this case, it is impossible to reliably stop the slider 15 and the piston 3 according to the prior art. In the present invention, the first spring device 16, the second spring device 17 and the like are provided, which is possible.

  First, as shown in FIG. 2, the first intermediate position 51 shown in FIG. 4 is moved to the third position by the operation of a control device (not shown) when the slider 15 is at or near the return end 47. This is realized by simultaneously shutting off power to the left and right solenoids 35 and 36 of the valve 14. As a result, the spool 32 of the three-position valve 14 moves to a neutral position as shown in FIG. 1 where the pressing forces of the left and right springs 33 and 34 are balanced, and the central air passage portion 39 of the spool 32 controls the valve cylinder 31. Since the ports 45 and 46 and the discharge ports 43 and 44 are communicated with each other, the left and right spaces 7 and 8 of the piston 3 in the air cylinder 1 are simultaneously communicated with the atmosphere and become atmospheric pressure.

  Since the slider 15 and the stay 2 are close to each other in the state shown in FIG. 2, the head 49 at the front end of the rod 18 in the first spring device 16 is in contact with the slider 15. Since the first spring 19 between the two is compressed, the left end of the first spring 19 presses the slider 15 to the left via the head 49. As a result, the slider 15 moves forward to the left, the nut 21 screwed into the male screw portion 20 of the rod 18 comes into contact with the stay 2, and the rod 18 can no longer move forward. Takes a first intermediate position 51 as shown in FIG.

  Thus, when the first spring device 16 is operating effectively, the distance between the slider 15 and the stay 2 is narrow, so the head 50 at the rear end of the rod 24 in the second spring device 17 is located rearward. Therefore, the compression force of the second spring 30 is received by the nut 28 and does not appear outside. Therefore, the operation of the second spring device 17 is invalid. When the slider 15 is pushed by the compression force of the first spring 19 and moves to the first intermediate position 51, the distance between the slider 15 and the stay 2 becomes the first intermediate value D2. The magnitude of the first intermediate value D2 and the first intermediate position 51 can be freely set and changed by adjusting the screwing position of the nut 21 on the rod 18 of the first spring device 16.

  Next, as illustrated in FIG. 3, the second intermediate position 52 shown in FIG. 5 is 3 by the operation of a control device (not shown) in a state where the slider 15 is at or near the forward end 48. This is realized by simultaneously shutting off power to the left and right solenoids 35 and 36 of the position valve 14. As a result, the spool 32 of the three-position valve 14 moves to a central position as shown in FIG. 1 where the pressing forces of the left and right springs 33 and 34 are balanced, and the central air passage portion 39 of the spool 32 controls the valve cylinder 31. Since the ports 45 and 46 and the discharge ports 43 and 44 are communicated with each other, the left and right spaces 7 and 8 of the air cylinder 1 are simultaneously communicated with the atmosphere and become atmospheric pressure.

  In the state shown in FIG. 3, the slider 15 and the stay 2 are largely separated from each other, so that the head 50 at the rear end of the rod 24 in the second spring device 17 is located relatively forward, and the spring receiver 27. The second spring 30 is compressed by the force transmitted from the slider 15 via the head 50 of the rod 24 and the spring receiver 27. In this state, both the left and right spaces 7 or 8 of the piston 3 of the air cylinder 1 are at atmospheric pressure, so that the slider 15 is moved by the urging force when the compressed second spring 30 is extended, and the rear end of the spring receiver 27 and the rod 24. Then, it is moved rearwardly through the head 50 and takes a second intermediate position 52 as shown in FIG.

  Thus, while the second spring device 17 is operating, the distance between the slider 15 and the stay 2 is increased, and the rod 18 in the first spring device 16 is advanced by the nut 21 engaged with the stay 2. Since the head 49 of the front end of the rod 18 is not engaged with the slider 15 because it is blocked, the urging force of the first spring 19 is received by the nut 21 and does not appear outside. Therefore, the operation of the first spring device 16 is invalid. When the slider 15 moves to the second intermediate position 52 shown in FIG. 5, the distance between the slider 15 and the stay 2 becomes the second intermediate value D3. The magnitude of the second intermediate value D3 and the second intermediate position 52 are freely set and changed by adjusting the screwing position of the nut 28 on the male screw part 26 of the rod 24 in the second spring device 17. be able to.

  In the illustrated embodiment, a first spring device 16 and a second spring device 17 are attached to the air cylinder 1 and the compressed air is supplied or discharged via the three-position valve 14. In addition to the return position as shown in FIG. 2 and the forward position as shown in FIG. 3, the piston 3 and the slider 15 have a first intermediate position as shown in FIG. 4 as an arbitrary position between them. Then, the second intermediate position as shown in FIG. 5 can be selectively and accurately taken. Therefore, since the air cylinder 1 can be used as a four-position stop air cylinder by adding a simple configuration, the four-position stop air cylinder can be provided at a low cost. Moreover, the first intermediate value D2 and the second intermediate value D3 can be set and changed easily and freely simply by adjusting the screwing position of the nut 21 in the first spring device 16 or the nut 28 in the second spring device 17. be able to.

  In the illustrated embodiment, the nut 21 that is screwed to the male screw portion 20 of the rod 18 in the first spring device 16 and the nut 28 that is screwed to the male screw portion 26 of the sleeve 25 in the second spring device 17 are both shown in the illustrated embodiment. Is used as a stopper for adjusting the degree of compression of the first spring 19 and the second spring 30. In the present invention, these stoppers are connected to the male screw portions 20, 26 as in the illustrated embodiment. Since it is not necessary to configure the nuts 21 and 28 which are female screws, it is possible to use an adjustable locking mechanism instead of the screw mechanism as a stopper.

  In the illustrated embodiment, the four-position stop air cylinder is provided with both the first spring device 16 and the second spring device 17, but the present invention provides the first spring device 16 and the second spring device. 17 is not an essential requirement, and there may be a case where only one of the first spring device 16 and the second spring device 17 is provided. Operates as

  Although the illustrated embodiment relates to an air cylinder, the present invention is generally applicable to a hydraulic cylinder since the same concept can be applied to a hydraulic cylinder. Further, the present invention can be used in various fields of machines such as processing devices and machine tools for various materials that conventionally require expensive position control devices such as servo motors.

It is a longitudinal cross-sectional view which shows the structure of an Example. It is a longitudinal cross-sectional view which shows the state in a return position. It is a longitudinal cross-sectional view which shows the state in an advance position. It is a longitudinal cross-sectional view which shows the state in a 1st intermediate position. It is a longitudinal cross-sectional view which shows the state in a 2nd intermediate position.

Explanation of symbols

1 ... Air cylinder 2 ... Stay (part of frame)
14 ... 3 position valve 15 ... Slider (driven part)
16 ... 1st spring device 17 ... 2nd spring device 18, 24 ... Rod 19 ... 1st spring 21, 28 ... Nut (stopper)
27 ... Spring receiver 30 ... Second spring 33, 34 ... Spring 35, 36 ... Solenoid (driving means)
37 ... Air passage portion 38 on the left side of the valve spool ... Air passage portion 39 on the right side of the valve spool ... Air passage portion 41 in the center of the valve spool ... Supply air sources 43, 44 ... Discharge ports 45, 46 ... Control port 47 ... return end 48 ... forward end 51 ... first intermediate position 52 ... second intermediate position

Claims (5)

A hydraulic cylinder attached to the frame;
A piston that divides the internal space of the fluid pressure cylinder into two space portions and reciprocates as the two space portions expand and contract;
A three-position valve comprising a valve spool having three fluid passage portions for switching and supplying pressurized fluid to the two space portions;
At least one drive means provided for reciprocating the valve spool of the three-position valve;
And a valve spool of the three-position valve is moved to the neutral position when the driving means of the valve is not energized, by communicating the fluid passage portion into two spatial portion of the cylinder in the neutral position, the At least one spring engaged with the valve spool to equalize the two space portions of the cylinder;
A driven part connected to the piston by a piston rod and positioned;
A first spring device provided between the driven portion and the frame and capable of arbitrarily giving a first intermediate position between a return position and an advanced position with respect to the driven portion;
A second spring equipment capable of providing a second intermediate position anywhere between a forward position and a return position relative to the driven portion provided between the frame and the driven portion,
The equipped,
The first spring device is inserted and supported in a hole formed in the frame and can move in parallel with the piston rod, and the first spring device can come into contact with the driven portion. A first spring mounted in a compressed state between a head provided on the rod and the frame; and a first stopper for limiting a movement range of the first rod; and
On the sleeve, the second spring device is attached to the driven part in parallel with the piston rod and can move while sliding in a sleeve attached to the frame; A spring receiver capable of moving while sliding and engaging with a head formed at a rear end of the second rod; and a spring receiver mounted in a compressed state between the frame and the spring receiver. An intermediate position stop cylinder comprising: a second spring; and a second stopper for limiting a moving range of the spring receiver . 2. The intermediate position stop cylinder according to claim 1 , wherein at least one of the stoppers includes a male screw portion and a nut screwed therein. The intermediate position stop cylinder according to claim 1 or 2 , wherein the valve spool of the three-position valve includes a pair of solenoids and a pair of springs at both ends thereof. 4. The intermediate position stop cylinder according to claim 3 , wherein both of the pair of springs are compression springs. The intermediate position stop cylinder according to any one of claims 1 to 4 , wherein the fluid pressure cylinder is an air cylinder.

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