JP5852850B2 - damper - Google Patents

Description

  The present invention relates to a damper used in an environment in which an external fluid such as cutting oil is easily scattered.

  As a damper, for example, as in Patent Document 1, there is a damper in which a piston is movably disposed through a piston rod in a fluid chamber of a cylinder filled with a fluid such as silicon oil. In this damper, when the piston rod receives an external force and makes a stroke, a predetermined damper effect can be generated by interlocking the piston in the fluid chamber.

  In such a damper, the outflow of the internal fluid and the intrusion of the external fluid to the fluid chamber are prevented by the seal, and the performance is stabilized.

  However, it is difficult to completely prevent the outflow of these internal fluids and the intrusion of external fluids. For this reason, if the damper is installed in an environment where external fluid such as cutting oil (coolant) is likely to scatter, the external fluid may enter the fluid chamber of the cylinder.

  In this case, the damper causes a so-called oil lock (piston rod lock), and the piston rod does not stroke at all or stops halfway, resulting in damage to the device to be buffered.

JP 2005-188601 A

  The problem to be solved is that the piston rod locks due to the intrusion of external fluid.

In order to prevent the piston rod from being locked due to the intrusion of an external fluid, the present invention communicates a fluid chamber in which a liquid is sealed in a cylinder and the piston is movable via the piston rod, and the inside and outside of the fluid chamber. An opening portion, a movable seal for sealing that is supported to be openable and closable with respect to the opening portion, and a biasing member that biases the movable seal to close the opening portion, The movable seal is a damper that moves against the urging force of the urging member due to an increase in internal pressure of the fluid chamber and opens the opening, and includes a spring recess that houses and holds the urging member, and the opening The section is defined between an outer peripheral surface of the piston rod and an inner peripheral surface on the cylinder side facing the outer peripheral surface of the piston rod, and the movable portion is movable at least partially in the circumferential direction on the inner peripheral surface on the cylinder side. Seal A diameter-enlarged portion that allows the opening to communicate with the spring recess by release movement, and from the opened opening to the spring recess side from the fluid chamber between the diameter-enlarged portion and the movable seal. The most important feature is that the piston rod is allowed to be immersed in the fluid chamber in accordance with the discharge of the liquid to prevent the lock .

  In the present invention, when the internal pressure of the fluid chamber rises, the opening can be opened to discharge the working fluid, and the piston rod can be prevented from being locked even if an external fluid enters the fluid chamber.

(Example 1) which is sectional drawing of a damper. FIG. 2 is an enlarged cross-sectional view of a main part of the damper of FIG. 1 (Example 1). FIG. 2 is a cross-sectional view showing a state in which an increase in internal pressure has occurred in the fluid chamber of the damper of FIG. 1 (Example 1). FIG. 4 is an enlarged cross-sectional view of a main part of the damper of FIG. 3 (Example 1). (Example 2) which is sectional drawing of a damper. (Example 2) which is a side view of the damper of FIG.

  The purpose of preventing the piston rod from being locked due to the intrusion of the external fluid is realized by a structure that allows the fluid in the fluid chamber to escape to the outside in response to an increase in the internal pressure of the fluid chamber.

  Specifically, an opening communicating with the inside and outside of the fluid chamber, a sealing movable seal supported so as to be openable and closable with respect to the opening, and urging the movable seal to close the opening. An urging member, and the movable seal moves against the urging force of the urging member due to an increase in the internal pressure of the fluid chamber to open the opening.

  Preferably, the opening is partitioned between the outer peripheral surface of the piston rod and the inner peripheral surface on the cylinder side facing the outer peripheral surface of the piston rod, and the inner peripheral surface on the cylinder side is movable at least partially in the circumferential direction. A diameter-enlarged portion that communicates with the opening by the opening movement of the seal is provided.

  The cylinder is preferably provided with a dust seal on the end side where the piston rod is pulled out, and the urging member is preferably provided between the dust seal and the movable seal.

  More preferably, an indicator is provided that allows the opening movement of the movable seal to be visually recognized from the outside.

  Embodiments of the present invention will be described below with reference to the drawings.

[Damper configuration]
1 is a cross-sectional view of a damper according to Embodiment 1 of the present invention, and FIG. 2 is an enlarged cross-sectional view of a main part of the damper of FIG. 3 is a cross-sectional view showing a state in which an increase in internal pressure has occurred in the fluid chamber of the damper of FIG. 1, and FIG. 4 is an enlarged cross-sectional view of the main part of the damper of FIG.

  As shown in FIGS. 1 and 3, the damper 1 includes a cylinder 3 and a piston 7 disposed in the cylinder 3 via a piston rod 5.

  The cylinder 3 is formed in a cylindrical shape, and one end side thereof is closed by a one end closing member 9. The one-end closing member 9 has a columnar shape that fits into the inner periphery of the cylinder 3, and holds an O-ring 13 that seals between the cylinder 3 and the outer periphery thereof. The one-end closing member 9 is supported by a nut 15 screwed to the inner periphery of the cylinder 3 so as to prevent it from coming off.

  A fluid chamber 17 is defined on one end side of the cylinder 3. In the fluid chamber 17, a working fluid (internal fluid) having viscosity such as silicon oil is enclosed. An inner cylinder 19 is disposed in the fluid chamber 17.

  One end of the inner cylinder 19 is supported on one end side of the cylinder 3 through the one end closing member 9, and the other end of the inner cylinder 19 is in addition to the cylinder 3 through the rod guide 21, the spacer 23, and the other end closing member 25. It is supported on the end side.

  The inner cylinder 19 forms a gap with the inner peripheral surface of the cylinder 3. A first accumulator 27 made of independently foamed rubber or the like is disposed in the gap. The first accumulator 27 communicates with the inner peripheral side of the inner cylinder via the annular flow path 29 of the one end closing member 9. The annular channel 29 is opened and closed by an open / close ball 31.

  On the inner peripheral side of the inner cylinder 19, the piston 7 is disposed so as to be capable of reciprocating, and a pressure chamber 33 and a non-pressure chamber 35 are partitioned. A return spring 37 is disposed between the piston 7 and the one end closing member 9 of the cylinder 3. The return spring 37 urges the piston 7 toward the non-pressure chamber 35 to return it to the initial position.

  One end of the return spring 37 is fitted and supported in a receiving recess 39 provided in the one-end closing member 9, and the other end is fitted and supported on the outer periphery of the protrusion 41 provided on the piston 7. The protrusion 41 is screwed into the inner end of the piston rod 5 that penetrates the piston 7. Thereby, the piston 7 is provided with the protrusion 41 and is fastened and fixed to the inner end of the piston rod 5.

  The outer end of the piston rod 5 is drawn to the outside from the other end side of the cylinder 3. The piston rod 5 is axially movable so as to perform a contraction operation with respect to the cylinder 3. As a result, the piston rod 5 moves the piston 7 in a reciprocating manner while moving in and out of the fluid chamber 17. The axial movement of the piston rod 5 is guided by the rod guide 21.

  The rod guide 21 is formed in a hollow cylindrical shape, and guides the piston rod 5 through the insertion hole 43 in the axial center. A circular recess 45 is formed in the intermediate portion on the outer peripheral side of the rod guide 21. A second accumulator 47 made of closed cell rubber or the like is accommodated and held in the recess 45.

  One end portion 49 of the rod guide 21 is abutted against the other end of the inner cylinder 19, and an outer periphery thereof forms a communication path 51 with the inner periphery of the cylinder 3. The communication path 51 allows the second accumulator 47 to communicate with the first accumulator 27.

  A communication hole 53 that communicates between the communication path 51 and the insertion hole 43 is formed in one end portion 49 of the rod guide 21. Accordingly, the first and second accumulators 27 and 47 communicate with the non-pressure chamber 35 through the communication passage 51, the communication hole 53, and the insertion hole 43 of the rod guide 21. Thereby, the inside of the fluid chamber 17 can absorb the volume change due to the protrusion and withdrawal of the piston rod 5 and the volume change of the working fluid.

  As shown in FIGS. 1 and 2, a movable seal 59 composed of an O-ring 57 and a U packing is supported on the other end 55 of the rod guide 21. The O-ring 57 and the movable seal 59 partition the fluid chamber 17 with the one end closing member 9 of the cylinder 3.

  The O-ring 57 is held in the outer peripheral recess 61 of the other end 55 to seal between the rod guide 21 and the cylinder 3. The movable seal 59 is held in the seal recess 63 on the inner periphery of the other end 55 to seal between the rod guide 21 and the piston rod 5.

  The seal recess 63 communicates with the non-pressure chamber 35 through the insertion hole 43 of the rod guide 21 and constitutes an opening 65 that communicates the inside and outside of the fluid chamber 17. Specifically, the opening 65 is defined by an outer peripheral surface 67 of the piston rod 5 and an inner peripheral surface 69 (an inner peripheral surface on the cylinder 3 side) of the seal recess 63 facing the outer peripheral surface 67. The movable portion 59 is closed by fitting the opening 65 to prevent the working fluid from flowing out of the fluid chamber 17.

  The movable seal 59 is supported on the outer periphery of the piston rod 5 so as to be movable in the axial direction. That is, the movable seal 59 is supported as a movable seal so as to be openable and closable with respect to the opening 65. The movable seal 59 is urged toward the opening 65 by a coil spring 73 as an urging member via a support plate 71 on the back side. Thereby, the movable seal 59 is kept in the fitted state to the opening 65. Accordingly, the coil spring 73 is configured to urge the movable seal 59 to close the opening 65.

  As shown in FIGS. 3 and 4, the movable seal 59 opens and moves to the counter fluid chamber side against the urging force of the coil spring 73 due to an increase in the internal pressure of the fluid chamber 17. The increase in the internal pressure of the fluid chamber 17 occurs when the volume of the working fluid exceeds the absorption amount of the first and second accumulators 27 and 47. When the movable seal 59 is located in the spring recess 75 on the spacer 23 side as a whole by this opening movement, the opening 65 is opened.

  As shown in FIGS. 1 and 2, the spacer 23 is formed in a hollow cylindrical shape, and the piston rod 5 is inserted through the insertion hole 77 in the axial center portion. One end side of the spacer 23 is abutted against the other end portion 55 of the piston rod 5. A spring recess 75 is provided on the inner periphery on one end side of the spacer 23.

  The spring recess 75 accommodates and holds a coil spring 73 that biases the movable seal 59. The spring recess 75 is formed to have substantially the same diameter as the seal recess 63 of the rod guide 21 and communicates with the seal recess 63. For this reason, the inner peripheral surface 79 of the spring recess 75 is an inner peripheral surface on the cylinder 3 side facing the outer peripheral surface 67 of the piston rod 5 together with the inner peripheral surface 69 of the seal recess 63.

  On the inner circumferential surface 79 of the spring recess 75, at least a part in the circumferential direction is provided with an enlarged diameter portion 81 that communicates with the opening 65 by the opening movement of the movable seal 59 along the axial direction. The enlarged diameter portion 81 of the present embodiment is formed in a groove shape and provided in a plurality in the circumferential direction. However, the enlarged diameter portion can also be provided in a circular shape over the entire circumferential direction.

  The axial dimension of the enlarged diameter portion 81 is set larger than that of the movable seal 59. As a result, the enlarged diameter portion 81 can communicate with both axial sides when the movable seal 59 is positioned in the spring recess 75 as shown in FIGS. 3 and 4.

  As shown in FIGS. 1 and 2, the other end closing member 25 is abutted against the other end side of the spacer 23, and the other end closing member 25 is connected to the other end of the cylinder 3 by a plate-like cap 83 and a snap ring 85. It is supported on the side.

  The other end closing member 25 is formed in a hollow cylindrical shape, and the piston rod 5 is inserted through the insertion hole 87 in the axial center. The other end closing member 25 is sealed from the cylinder 3 by holding an O-ring 91 on the outer periphery thereof.

The inner periphery of the other end closing member 25 is sealed between the piston rod 5 by holding a dust seal 95 as a dust seal in the recess 93. Therefore, in this embodiment, the coil spring 73 is provided between the movable seal 59 and the dust seal 95. The dust seal 95 is directed in the opposite direction to the movable seal 59 held by the rod guide 21 and prevents intrusion of external fluid.
[Damper operation]
When the outer end of the piston rod 5 receives an external force from the object to be buffered, the damper 1 strokes the piston rod 5 into the cylinder 3 by contraction movement as shown in FIGS. 3 and 4 show the time when the internal pressure of the fluid chamber 17 increases, the movable seal 59 is in an open state. However, during normal operation, the movable seal 59 is in a closed state.

  With this stroke, the piston rod 5 moves the piston 7 in the axial direction in conjunction with the pressure chamber 33 while immersing in the fluid chamber 17.

  When the piston 7 moves, the working fluid moves to the non-pressure chamber 35 side through the space between the inner cylinder 19 in the cylinder 3 and the piston 7, and a predetermined damper effect can be exhibited. At this time, in the damper 1, the volume change in the fluid chamber 17 due to the immersion of the piston rod 5 and the volume change of the working fluid due to thermal expansion are absorbed by the first and second accumulators 27, 47, and the piston rod 5 is reliably Can be stroked.

  On the other hand, when the external force is buffered by the damper effect, the piston 7 moves back in the axial direction toward the non-pressure chamber 35 by the biasing force of the return spring 37. In response to this, the piston rod 5 is pulled out from the fluid chamber 17 in the extending direction with respect to the cylinder 3.

  At this time, the working fluid circulates from the first and second accumulators 27 and 47 to the pressure chamber 33 side via the annular flow path 29 of the one-end closing member 9.

  Thus, in the damper 1, the piston rod 5 can be reliably stroked to exhibit a predetermined damper effect.

  When the damper 1 is used in an environment in which an external fluid such as cutting oil (coolant) is likely to scatter, the external fluid may enter the internal fluid chamber 17. In this case, the volume of the working fluid in the fluid chamber 17 is increased by the amount of the external fluid. The increase in the volume of the working fluid can be absorbed to some extent by the first and second accumulators 27 and 47.

  However, when the external fluid enters beyond the amount of absorption of the accumulators 27 and 47, it becomes impossible to absorb the volume change due to the immersion into the fluid chamber 17 during the contraction stroke of the piston rod 5. As a result, an increase in internal pressure corresponding to a volume change that cannot be absorbed occurs in the fluid chamber 17.

  The damper 1 of the present embodiment allows the working fluid in the fluid chamber 17 to escape to the outside in response to the increase in internal pressure.

  That is, in the damper 1, as shown in FIGS. 3 and 4, when the internal pressure rises in the fluid chamber 17 due to the immersion of the piston rod 5, the working fluid in the fluid chamber 17 is transferred to the working fluid in the fluid chamber 17 through the insertion hole 43 of the rod guide 21. Pressed. By this pressing, the movable seal 59 moves open from the opening 65 of the seal recess 63 toward the detachment direction against the urging force of the coil spring 73.

  Thereafter, when the piston rod 5 is fully immersed and is completely removed from the opening 65, the movable seal 59 is located in the spring recess 75 on the spacer 23 side as a whole. At this time, the opening 65 is opened by communication with the enlarged diameter portion 81 of the spring recess 75, that is, by internal and external communication with the movable seal 59 via the enlarged diameter portion 81.

  From the opening 65 thus opened, the working fluid (mixed fluid with the external fluid) in the fluid chamber 17 is discharged to the outside through the enlarged diameter portion 81 as shown by the arrow in FIG. Depending on the discharge, immersion into the fluid chamber 17 is allowed.

  Therefore, in the damper 1 of the present embodiment, even if an external fluid enters the fluid chamber 17, the piston rod 5 is prevented from being locked (oil lock), and damage to a device to be buffered can be suppressed. .

The working fluid discharged from the fluid chamber 17 is appropriately discharged out of the cylinder 3 through the dust seal 95 oriented in the intrusion prevention direction. In addition, after the working fluid is discharged, the movable seal 59 closes the opening 65 again by the biasing force of the coil spring 73.
[Effect of Example 1]
The damper 1 of the present embodiment includes a fluid chamber 17 in which a working fluid is sealed in a cylinder 3 and the piston 7 is movably disposed via a piston rod 5, and an opening 65 that communicates the inside and outside of the fluid chamber 17. , A sealing movable seal 59 supported so as to be openable and closable with respect to the opening 65, and a coil spring 73 that urges the movable seal 59 to close the opening 65. When the internal pressure of the fluid chamber 17 rises, it moves against the urging force of the coil spring 73 to open the opening 65.

  Therefore, in the damper 1, the working fluid can be discharged by opening the opening 65 when the internal pressure of the fluid chamber 17 rises, and oil lock can be prevented even if an external fluid enters the fluid chamber 17. As a result, the damper 1 can suppress damage to a device to be buffered.

  The opening 65 is defined between an outer peripheral surface 67 of the piston rod 5 and an inner peripheral surface 69 on the cylinder 3 side facing the outer peripheral surface 67 of the piston rod 5, and the inner peripheral surface 69 on the cylinder 3 side is at least A diameter-expanded portion 81 that communicates with the opening 65 by the opening movement of the movable seal 59 is provided in a part of the circumferential direction.

  Therefore, in the damper 1, the opening 65 can be easily and reliably opened via the enlarged diameter portion 81 only by moving the movable seal 59 to be opened by increasing the internal pressure.

  In the damper 1 of this embodiment, the fluid chamber 17 is provided on one end side of the cylinder 3, the piston rod 5 is drawn out from the other end side of the cylinder 3, and the other end side of the cylinder 3 is between the piston rod 5. An interposed dust seal 95 is provided, and a coil spring 73 is provided between the movable seal 59 and the dust seal 95.

  For this reason, in this embodiment, the coil spring 73 can be arranged without difficulty, and the movable seal 59 can be reliably opened and closed.

  In addition, in this embodiment, the spring recess 75 is provided in the inner periphery of the spacer 23 interposed between the rod guide 21 and the other end closing member 25, and the coil spring 73 is accommodated in the spring recess 75. By utilizing the inner peripheral side of 23, an increase in size as a whole can be suppressed while the coil spring 73 is disposed.

  In the present embodiment, since the enlarged diameter portion 81 is also provided in the spring recess 75, it is not necessary to directly process the inner periphery of the cylinder 3, and the existing cylinder 3 can be used.

  The damper 1 of this embodiment includes first and second accumulators 27 and 47 that communicate with the fluid chamber 17 and absorb the volume change in the fluid chamber 17 and the volume change of the working fluid, and the movable seal 59 is the first. When the volume of the working fluid exceeds the amount of absorption of the second accumulators 27 and 47, the opening 65 is opened due to an increase in the internal pressure of the fluid chamber 17.

  Therefore, the damper 1 can reliably prevent oil lock when the external fluid enters the fluid chamber 17 while stabilizing the performance by the first and second accumulators 27 and 47.

  5 is a cross-sectional view of a damper according to Embodiment 2 of the present invention, and FIG. 6 is a side view of the damper of FIG. In this embodiment, since the basic configuration is the same as that of the first embodiment, the same reference numerals are used for the corresponding parts, or redundant descriptions are omitted using the same reference numerals.

  As shown in FIGS. 5 and 6, the damper 1 </ b> A of the present embodiment includes an indicator 97 that makes it possible to visually recognize the opening movement of the movable seal 59.

  That is, the indicator 97 includes a window portion 99 provided in the cylinder 3A so that the inside can be visually recognized. The window 99 is configured by, for example, fitting a glass plate into a through hole that penetrates the inner and outer circumferences of the cylinder 3. This window part 99 is formed in the shape of a long hole along the axial direction. On the inner peripheral side of the window portion 99, a through hole 101 penetrating the inner and outer periphery is formed in the spring recess 75A of the spacer 23A.

  In the damper 1 </ b> A, when the movable seal 59 opens and moves against the urging force of the coil spring 73, it faces the window portion 99 of the indicator 97.

  For this reason, in the damper 1A of the present embodiment, the intrusion of the external fluid into the fluid chamber 17 can be visually recognized from the outside through the opening movement of the movable seal 59. As a result, in the present embodiment, maintenance, replacement, etc. can be promoted, and damage to the device to be buffered can be more reliably suppressed.

In addition, also in the present embodiment, the same effects as those of the first embodiment can be obtained.
[Others]
As mentioned above, although the Example of this invention was described, this invention is not limited to this, Various design changes are possible.

  For example, although the U packing is used as the movable seal in the first embodiment, other seals such as an X ring and an O ring can be used. This also applies to the dust seal.

  Further, an elastic body other than the coil spring can be used as the urging member.

  The accumulator can be a free piston. In this case, by restricting the maximum movement amount of the free piston, it is possible to cause the movable seal 59 to perform an opening movement due to an increase in the internal pressure of the fluid chamber.

1 damper 3 cylinder 5 piston rod 7 piston 27 first accumulator 47 second accumulator 59 movable seal 65 opening 67 outer peripheral surface (piston rod)
69 Inner peripheral surface (cylinder side)
73 Coil spring (biasing member)
81 Expanded portion 95 Dust seal 97 Indicator 99 Window

Claims (4)

A fluid chamber in which a liquid is enclosed in a cylinder and the piston is movably disposed via a piston rod;
An opening communicating the inside and outside of the fluid chamber;
The enclosing movable seal supported so as to be openable and closable with respect to the opening;
A biasing member that biases the movable seal to close the opening,
The movable seal is a damper that moves against an urging force of the urging member due to an increase in internal pressure of the fluid chamber and opens the opening ,
A spring recess for receiving and holding the biasing member;
The opening is defined between an outer peripheral surface of the piston rod and an inner peripheral surface on the cylinder side facing the outer peripheral surface of the piston rod,
On the inner circumferential surface on the cylinder side, at least part of the circumferential direction is provided with a diameter-enlarged portion that causes the opening to communicate with the spring recess by opening movement of the movable seal ,
The piston rod is allowed to enter the fluid chamber in response to the discharge of liquid from the fluid chamber to the spring recess side through the gap between the enlarged diameter portion and the movable seal from the opened opening. Prevent locks,
A damper characterized by that. The damper according to claim 1 , wherein
The fluid chamber is provided on one end side of the cylinder,
The piston rod is pulled out from the other end side of the cylinder,
The other end side of the cylinder includes a dust seal interposed between the piston rod,
The biasing member is provided between the dust seal and the movable seal.
A damper characterized by that. The damper according to claim 1 or 2 ,
The cylinder includes a window portion that allows the inside to be visually confirmed,
The movable seal faces the window portion by movement against the biasing force of the biasing member.
A damper characterized by that. A damper according to any one of claim 1 to 3
An accumulator that communicates with the fluid chamber and absorbs a volume change in the fluid chamber and a volume change of the liquid ;
The movable seal performs the opening by increasing the internal pressure of the fluid chamber when the volume of the liquid exceeds the absorption amount of the accumulator.
A damper characterized by that.

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