JP4993961B2 - shock absorber - Google Patents

Description

  The present invention relates to a shock absorber that reduces an impact force applied to a moving member when the moving member is stopped, and more particularly to a shock absorber that can be used in a pressurized state atmosphere.

  A shock absorber, ie, a shock absorber, is used to relieve the impact force applied to the moving member when the reciprocating moving member stops at the position of the reciprocating end. For example, when an electronic component or the like is moved by a reciprocating table, the reciprocating table is linearly reciprocated by a pneumatic cylinder. When the reciprocating table is moved to the position of the reciprocating end, the cylinder body is reciprocated. The table will collide and stop. Therefore, a shock absorber may be attached to the cylinder body in order to relieve the impact force applied to the cylinder body by the reciprocating table when stopping the reciprocating member.

As a shock absorber used in such applications, a rod is projected from one end of a cylindrical case so that a reciprocating table as a moving member collides with the rod, and the rod reciprocates while moving backward in the cylindrical case. There is a type that absorbs the impact of the moving table (see Patent Documents 1 and 2). In this type of shock absorber, a coil spring that applies a spring force in the protruding direction to the rod is incorporated in the cylindrical case, and a shock-absorbing liquid such as silicone oil is enclosed. The piston fixed to the rod The rod moves backward in the liquid.
Japanese Utility Model Publication No. 61-55530 Japanese Utility Model Publication No. 62-194946

  FIG. 3 is a view showing a slide table type pneumatic cylinder having a cylinder body 1 and a reciprocating table 3 which is reciprocally mounted on a guide rail 2 provided on the cylinder body 1. In this type of pneumatic cylinder, the reciprocating rod 4 provided in the cylinder body 1 is connected to the reciprocating table 3 via a connecting member 3a, and the reciprocating rod 4 drives the reciprocating table 3. In order to absorb the impact at the stroke end of the reciprocating rod 4 or the reciprocating table 3, shock absorbers 5a and 5b are attached to the cylinder body 1 through brackets 6a and 6b, and the reciprocating table 3 has a shock absorber. A stopper 8 on which the rods 7a and 7b of the 5a and 5b collide is attached.

  When the shock absorbers 5 a and 5 b are attached to the reciprocating table 3, stoppers on which the rods 7 a and 7 b of the shock absorbers 5 a and 5 b collide are attached to the cylinder body 1. In either case, the rods 7a and 7b absorb the shock of the reciprocating table 3 while moving backward in the cylindrical cases of the shock absorbers 5a and 5b.

  As shown in FIG. 3, conventionally, shock absorbers 5a and 5b are provided outside the cylinder to absorb the impact of the reciprocating member. In this case, a metal fitting for mounting the shock absorbers 5a and 5b is provided. It is necessary to secure a space for this outside the cylinder. Also, even if the shock absorber is attached using metal fittings, the cylinder piston shaft and the shock absorber piston shaft are not concentric, so a moment is generated each time an impact is absorbed, and the accuracy of the cylinder device gradually deteriorates. There is a problem that the product life is shortened due to the rattling.

  In addition to the pneumatic cylinder having the piston rod shown in FIG. 3, there are rodless cylinders that do not use the piston rod, and there are a slit type and a magnet type as the rodless cylinder. In the slit type, the piston yoke that connects the piston inside the cylinder and the piston mount outside the cylinder is moved along the slit formed in the cylinder, and the slit is sealed by the inner and outer sealing bands. It is a pneumatic cylinder. The magnet type is a pneumatic cylinder of a type in which a piston inside a cylinder tube and an external slider are connected by magnetic force.

  In the rodless type cylinder, a rubber shock absorbing member is attached to the head cover attached to the end of the cylinder or tube so that the internal piston does not directly collide, and this shock absorbing member absorbs the impact of the piston. Like to do. If the shock absorber is attached to the head cover instead of the rubber shock absorbing member, the shock absorbing effect is increased. In that case, it is necessary to attach the shock absorber to the head cover so that the tip of the shock absorber enters the pressure chamber of the cylinder. With such an installation, there is no need for metal fittings as in the case of external installation, and there is no need for a space for installation, and the piston shaft of the cylinder and the piston shaft of the shock absorber are concentric, so every time an impact is absorbed. There is no moment. However, since the pressurized air in the pressure chamber gradually flows into the shock absorber, there is a problem that the accumulator gradually collapses due to the air and fluid flowing in through the seal and the function of the shock absorber deteriorates. .

  An object of the present invention is to provide a shock absorber that can be mounted so as to enter a pressure chamber.

The shock absorber according to the present invention is a shock absorber that is attached to a fluid pressure device having a pressure chamber with a tip exposed in the pressure chamber, and is installed in the fluid pressure device and is filled with liquid. A cylindrical case in which a chamber is provided and a rod is reciprocally mounted in an axial direction; a piston that is mounted on the rod and moves in the liquid storage chamber; and is mounted in the cylindrical case; A spring member for applying a spring force in a direction in which the tip portion projects from the one end of the cylindrical case into the pressurizing chamber, and an inner seal member that contacts the outer peripheral surface of the rod and seals the liquid in the liquid storage chamber And an outer seal member that contacts the outer peripheral surface of the rod on the outer side in the axial direction of the inner seal member and seals the fluid from the tip end side of the rod into the cylindrical case, Provided Jo case, and having a discharge passage for discharging the outer sealing member and the fluid that has entered the inside of the outer sealing member from said pressure chamber through between said rod to the outside .

  The shock absorber according to the present invention includes the inner case body in which the rod and the spring member are incorporated, and the outer case body in which the inner case body is incorporated and forms the discharge channel between the inner case body and the cylinder. A shape case is formed, and an opening of the discharge channel is formed at an end of the outer case body.

  In the shock absorber of the present invention, the inner seal member is a V-shaped seal member with the pressure side facing inward, and the outer seal member is a V-shaped seal member with the pressure side facing outward. It is characterized by being.

  According to the present invention, the tip end side of the shock absorber is exposed to the pressurizing chamber and the shock absorber is attached to the fluid pressure device. Even if the fluid in the pressurizing chamber enters the shock absorber, it is exposed to the outside through the discharge passage. Since the fluid is discharged, it is possible to prevent the fluid from entering the liquid in the shock absorber from the outside. Thereby, even if the shock absorber is installed in the pressure chamber to which the pressurized fluid is supplied, the durability can be enhanced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a shock absorber according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a pneumatic actuator equipped with the shock absorber shown in FIG.

  The shock absorber 10 has a cylindrical inner case body 11 and an outer case body 12, and the inner case body 11 is incorporated in the outer case body 12, and the cylindrical case 13 is formed by both case bodies 11 and 12. Is formed. A male screw 14 is formed on the outer peripheral surface of the outer case body 12, and the shock absorber 10 is screwed to the pneumatic actuator by the male screw 14.

  The inner case body 11 has a liquid storage chamber 15 formed therein, and the left end portion in FIG. 1 is a tip portion, and the right end portion is a base end portion. A front end portion of the inner case body 11 is opened, and a closing portion 16 is provided at the base end portion. A holder 17 comprising a cylindrical member 17b having flanges 17a provided at both ends is incorporated inside the inner case body 11, and a rod 21 is supported by a rod through hole 18 of the holder 17 so as to be capable of reciprocating in the axial direction. The tip of the rod 21 protrudes outside the cylindrical case 13.

  A piston 22 is attached to the base end portion of the rod 21, and a gap 23 is formed between the outer peripheral surface of the rod 21 and the inner peripheral surface of the piston 22. The rod 21 is integrally provided with a flange portion 24 on the distal end side with respect to the piston 22, and a cylindrical spring receiver 25 is fitted on the proximal end portion side with respect to the piston 22. It moves slightly in the radial direction with respect to the rod 21 and is slightly movable in the axial direction between the flange portion 24 and the flange portion 25a of the spring receiver 25.

  The interior of the liquid storage chamber 15 is partitioned by the piston 22 into a spring chamber 15a on the proximal end side of the inner case body 11 and an accumulator chamber 15b on the distal end side. A compression coil spring 26 is incorporated as a spring member between the spring receiver 25 and the closing portion 16, and the tip of the rod 21 protrudes from the tip of the cylindrical case 13 by the compression coil spring 26. That is, a spring force is applied in the forward direction.

  Silicone oil is sealed in the liquid storage chamber 15 as a shock absorbing liquid L. In order to inject the liquid L into the liquid storage chamber 15, the closed portion 16 is formed with a recess 16 a that opens to the outer end surface thereof, and a liquid injection hole 27 that communicates with the recess 16 a is formed in the closed portion 16. Yes. A set screw 28 is attached to the liquid injection hole 27, and the seal member 29 is fastened to the bottom surface of the recess 16 a by the set screw 28. Therefore, after the liquid L is injected into the inner case body 11, the set screw 28 is screwed to the liquid injection hole 27 and the seal member 29 is fastened to prevent leakage of the liquid L from the liquid injection hole 27. The

  An accumulator 30 is incorporated between the holder 17 and the inner case body 11 in the accumulator chamber 15b. The accumulator 30 is formed of, for example, a closed-cell sponge, and the rod 21 enters the liquid L when the rod 21 moves backward against the spring force. Therefore, the accumulator 30 enters the liquid L from the spring chamber 15a through the gap 23. Shrinkage is caused by the liquid L entering the accumulator chamber 15b. On the other hand, when the rod 21 moves forward, the volume of the spring chamber 15a increases in the rod 21, so that the liquid L in the accumulator chamber 15b flows into the spring chamber 15a and the accumulator 30 expands.

  A rod cover 31 is press-fitted and attached to the tip of the inner case body 11, that is, the opening. The rod cover 31 is positioned between the rod cover 31 and the holder 17 to contact the outer peripheral surface of the rod 21, and the liquid storage chamber. An inner seal member 32 that seals the liquid in 15 and prevents the liquid L from leaking to the outside is disposed. A rod cover 33 is fixed to a front end portion, that is, an opening portion of the outer case body 12 by a retaining ring 34, and an end surface of the rod cover 33 is abutted against an end surface of the rod cover 31. A seal member 35 seals between the outer peripheral surface of the rod cover 33 and the inner peripheral surface of the outer case body 12. An outer seal member 36 that contacts and seals the outer peripheral surface of the rod 21 at an axially outer portion of the rod cover 31 is disposed on the rod cover 33.

  An annular clearance 41 is formed between the inner peripheral surface of the rod cover 31 and the outer peripheral surface of the rod 21, and this clearance 41 is an annular formed on the outer peripheral surface of the rod cover 31 by a radial communication hole 42. Further, the gap 43 communicates with a passage 45 formed between the inner case body 11 and the outer case body 12 through a communication hole 44 formed in the inner case body 11. The passage 45 communicates with a discharge hole 46 formed in the closed portion of the outer case body 12. A discharge flow path is formed by the discharge hole 46 from the communication hole 42 described above, and the fluid that has entered the inside of the outer seal member 36 from between the outer seal member 36 and the rod 21 passes through the discharge flow path to the outside. Discharged.

  Each of the inner seal member 32 and the outer seal member 36 is a V-shaped seal member also called a V-packing, and has inner and outer annular portions, both of which are connected at one end in the axial direction. The end portions are pressure sides that can approach and separate from each other in the radial direction. The outer seal member 36 is arranged with the pressure side facing outward. When pressure is applied from the outside, the pressure side is elastically deformed in a direction away from each other, and the inner annular portion is strongly against the outer peripheral surface of the rod 21. The outer annular portion comes into contact with the inner peripheral surface of the rod cover 33 strongly. Thereby, the outer seal member 36 prevents intrusion of fluid from the outside, but if the pressure of the fluid applied from the outside, that is, air or liquid is high, the intrusion of fluid may not be sufficiently prevented. There is.

On the other hand, the inner seal member 32 is arranged with the pressure side facing inward. Accordingly, the pressure side is elastically deformed in a direction away from each other by the liquid L inside, the inner annular portion is in strong contact with the outer peripheral surface of the rod 21, and the outer annular portion is strongly against the inner peripheral surface of the inner case body 11. Since the inner seal member 32 is in contact with the inner seal member 32, the liquid L is prevented from leaking to the outside, and when the high pressure fluid pressure is applied to the inner seal member 32 from the outside, the inner seal member 32 cannot prevent the intrusion.

  Even if the outer seal member 36 cannot prevent intrusion and fluid enters the internal gap 41 from the outside via the outer seal member 36, the gap 41 communicates with the outside via the discharge hole 46. Therefore, it is prevented from entering the inside through the inner seal member 32. When such a discharge hole 46 is not provided, the high pressure fluid from the outside that could not be prevented from entering by the outer seal member 36 cannot be prevented from entering even by the inner seal member 32, and the high pressure fluid cannot be prevented from entering. However, in the present invention, the outer seal member is disposed on the outer side in the axial direction of the inner seal member 32. However, in the present invention, the function of the shock absorber is lowered. By providing the discharge passage communicated between them, the external fluid that could not be prevented from entering by the outer seal member 36 is released to the atmosphere through the discharge passage. The function of the shock absorber is not deteriorated without entering the liquid storage chamber 15 or the accumulator 30.

  FIG. 2 is a cross-sectional view showing an example of a pneumatic operating device to which the shock absorber 10 is attached. This pneumatic driving device is a rodless having a cylinder tube 50 made of a round pipe and head covers 51 and 52 fixed to both ends thereof. This is a pneumatic cylinder of the type, MRC series magnet type rodless cylinder manufactured by KOGANEI Corporation. A piston 54 having a magnet 53 is mounted in the cylinder tube 50 so as to be capable of reciprocating in the axial direction. The cylinder 54 is partitioned into two pneumatic chambers 55 and 56 by the piston 54. The head cover 51 is formed with a supply / discharge port 51 a communicating with the pneumatic chamber 55, and the head cover 52 is formed with a supply / discharge port 52 a communicating with the pneumatic chamber 56.

  A slider 58 having a magnet 57 corresponding to the piston 54 is fitted to the outside of the cylinder tube 50. The slider 58 is coupled to the piston 54 by magnetic force, and follows the piston 54 in the axial direction. Moving. Accordingly, when pressurized air is supplied from the supply / discharge port 51a into the pneumatic chamber 55 and the air in the pneumatic chamber 56 is discharged from the supply / discharge port 52a, the piston 54 is driven to the position of the right stroke end in FIG. The slider 58 is also driven by the piston 54 through the magnetic force to the position of the right stroke end. Conversely, when pressurized air is supplied from the supply / discharge port 52a into the pneumatic chamber 56 and the air in the pneumatic chamber 55 is discharged from the supply / discharge port 51a, the piston 54 reaches the left stroke end position as shown in FIG. The slider 58 is also driven to the stroke end position shown in the drawing.

  The shock absorbers 10 shown in FIG. 1 are attached to the head covers 51 and 52, respectively. Each of the shock absorbers 10 is screwed to the head covers 51 and 52 at the portion of the male screw 14 formed on the outer case body 12, and is fastened to the head covers 51 and 52 by a nut 61. The front end surface of the shock absorber 10 enters. A seal member 62 is provided between the nut 61 and the head covers 51 and 52 in order to prevent air leakage from the pneumatic chambers 55 and 56.

  FIG. 2 shows a state in which the piston 54 has moved to the position of the left stroke end. The rod 21 of the shock absorber 10 attached to the right head cover 52 protrudes to the forward limit position and is attached to the left head cover 51. The rod 21 of the shock absorber 10 is in a state of being pushed down by the piston 54 that is in contact with the opening end surface of the cylindrical case 13 of the shock absorber 10.

  Each shock absorber 10 shown in FIG. 2 is attached to the head covers 51 and 52 with the tip portions from which the rod 21 protrudes exposed to the pneumatic chambers 55 and 56. When compressed air in each of the pneumatic chambers 55 and 56 enters the inside of the shock absorber from between the outer seal member 36 and the rod 21, the gap 41 between the rod 21 and the rod cover 31 communicates with the discharge hole 46. Therefore, the inflow air is discharged from the discharge hole 46. This prevents the inflow air from entering the inside of the shock absorber liquid L, and prevents the fluid from entering the inside even when the rod 21 is exposed to a pressurized atmosphere. Durability can be improved.

  The shock absorber 10 is attached to a magnet type rodless cylinder in the case shown in FIG. 2, but a shock absorber can also be attached to an end cap of a slit type rodless cylinder. Further, even in a single acting cylinder in which the rod is reciprocated, the shock absorber 10 can be attached to the head cap on the side opposite to the protruding side of the rod. In that case, it is possible to prevent the compressed air in the pneumatic chamber from entering the liquid L inside the shock absorber by mounting the tip of the shock absorber 10 in communication with the pneumatic chamber. Similarly, when the shock absorber is used in a fluid pressure device in a state where the tip side of the shock absorber is exposed to a pressurized fluid such as pressurized air, the shock absorber 10 is affected by the pressurized fluid. And can absorb the impact force.

  In the shock absorber 10 shown in FIG. 1, the cylindrical case 13 is formed by the inner case body 11 and the outer case body 12, but the cylindrical case may be formed by a member in which these are integrated. In that case, an exhaust passage is formed inside the cylindrical case.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the shock absorber type is not limited to the illustrated type, and the present invention can be applied to any type of shock absorber that is filled with liquid and absorbs shock by moving the liquid. can do.

It is sectional drawing which shows the shock absorber which is one embodiment of this invention. It is sectional drawing which shows the pneumatic actuator with which the shock absorber shown by FIG. 1 was mounted | worn. It is a perspective view showing a slide table type pneumatic cylinder having a cylinder body and a reciprocating table.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shock absorber 11 Inner case body 12 Outer case body 13 Cylindrical case 15 Liquid storage chamber 15a Spring chamber 15b Accumulator chamber 17 Holder 21 Rod 22 Piston
26 compression coil spring 30 accumulator 32 inner seal member 36 outer seal member 45 passage (discharge passage)
46 Discharge hole

Claims (3)

A shock absorber attached to a fluid pressure device having a pressurizing chamber with its tip exposed to the pressurizing chamber,
A cylindrical case attached to the fluid pressure device, provided with a liquid storage chamber filled with liquid , and mounted with a rod reciprocally movable in an axial direction;
A piston mounted on the rod and moving in the liquid chamber;
A spring member that is mounted in the cylindrical case and applies a spring force in a direction that causes the tip of the rod to protrude from one end of the cylindrical case into the pressurizing chamber ;
An inner seal member that contacts the outer peripheral surface of the rod and seals the liquid in the liquid storage chamber;
An outer seal member that contacts the outer peripheral surface of the rod on the axially outer side of the inner seal member, and seals fluid from the tip end side of the rod into the cylindrical case;
A discharge passage provided in the cylindrical case and for discharging the fluid that has entered the inside of the outer seal member from the pressurizing chamber through the space between the outer seal member and the rod; Shock absorber.
  The shock absorber according to claim 1, comprising: an inner case body in which the rod and the spring member are incorporated; and an outer case body in which the inner case body is incorporated to form the discharge flow path between the inner case body. A shock absorber characterized by forming the cylindrical case and forming an opening of the discharge channel at an end of the outer case body.   3. The shock absorber according to claim 1 or 2, wherein the inner seal member is a V-shaped seal member with the pressure side facing inward, and the outer seal member has a V-shaped cross section with the pressure side facing outward. A shock absorber characterized by being a seal member.

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