TW201802369A - Gas spring device - Google Patents

Abstract

The present invention reduces the sliding resistance of a push rod part with respect to a piston rod part and thus improves the movability of the push rod part. A push rod part 12 has a valve member 13 that opens and closes a communication path 9 communicating between an upper oil chamber B and a lower oil chamber C formed in a cylinder 2. In the push rod part 12, the lower end of a rod member 14, which is the end opposite from a piston 7, is formed to serve as a cap member 15 and is thus formed of a resin material.

Description

Gas spring device

The present invention relates to a gas spring device suitable for, for example, a backrest angle adjustment mechanism and a height adjustment mechanism provided in a chair, a bed, or the like.

In general, chairs, beds, and the like that can adjust the angle and height of each part according to the physique and posture of the user are known. For example, the backrest angle adjustment mechanism for adjusting the backrest angle of the chair and the height adjustment mechanism for adjusting the height of the seat portion of the chair use a gas spring device.

This gas spring device uses a rotatable external lever to push the end of the push rod portion protruding from the piston rod into the piston rod. Thereby, the valve part provided in the push rod part is opened and closed, and the expansion-contraction size of a piston rod part can be adjusted (for example, refer patent document 1).

[Patent Document 1] Japanese Patent Application Publication No. 2012-13154

However, the gas spring device of Patent Document 1 is configured such that an end portion of a pusher portion protruding from a piston rod uses a rotatable external lever promote. According to this configuration, the outer lever abuts obliquely with respect to the end of the pusher portion, so that a lateral force may be applied to the pusher portion. When a lateral force is applied to the pusher portion, the pusher portion is pressed against the inner peripheral surface of the piston rod portion to increase the sliding resistance, and the operability of the pusher portion may be deteriorated.

The present invention has been developed in view of the problems of the above-mentioned conventional technology, and an object of the present invention is to provide a gas spring device that reduces the sliding resistance of a push rod portion to a piston rod portion to improve the operability of the push rod portion. .

A gas spring device according to the present invention includes a cylinder block, a piston portion, a piston rod portion, a communication path, and a push rod portion. The cylinder block is filled with a pressurized gas inside; the piston portion is slidably inserted into the cylinder body. And the cylinder body is divided into two chambers; one end of the piston rod part is connected to the piston part and the other end extends to the outside of the cylinder body; the communication path is to communicate the two chambers formed in the cylinder body. The pusher portion is provided with a valve portion that opens and closes the communication path; the pusher portion is operated from outside to open the communication path, and the axial length of the piston rod portion with respect to the cylinder can be adjusted, and is characterized in that: Among the aforementioned pusher portions, at least the end portion opposite to the piston portion side is formed using a resin material.

According to the present invention, the sliding resistance of the push rod portion to the piston rod portion can be reduced, and the operability of the push rod portion can be improved.

1‧‧‧ Gas Spring Device

2‧‧‧cylinder block

7,82‧‧‧Piston

8,21,31,41,51,83‧‧‧Piston rod

9‧‧‧ Link Road

10,84‧‧‧Plug-in hole

12,61,71,85‧‧‧Putter

13‧‧‧Valve member (valve part, stem body)

14,33,43,53,62 ‧‧‧ rod members (rod body)

15,34,44,54‧‧‧‧cover member

16‧‧‧External leverage

22,32,42,52‧‧‧Sliding bearings

71A, 85A‧‧‧ Valve

B‧‧‧ Upper side oil chamber

C‧‧‧ Lower side oil chamber

Fig. 1 is a longitudinal sectional view showing a gas spring device according to a first embodiment of the present invention.

2 is a longitudinal sectional view showing an enlarged lower end portion of a piston rod portion and a lower end portion of a push rod portion in FIG. 1.

3 is a longitudinal sectional view of a piston rod portion, a sliding bearing, and a push rod portion according to a second embodiment of the present invention, as viewed from the same position as FIG. 2.

FIG. 4 is a longitudinal cross-sectional view of a push rod portion, a piston rod portion, and the like of a third embodiment of the present invention, viewed from the same position as FIG. 2.

5 is a longitudinal sectional view of a piston rod portion, a sliding bearing, and a push rod portion according to a fourth embodiment of the present invention, as viewed from the same position as FIG. 2.

FIG. 6 is a longitudinal sectional view of a plunger portion, a piston rod portion, and the like according to a fifth embodiment of the present invention, viewed from the same position as FIG. 2.

FIG. 7 is a longitudinal cross-sectional view of a gas spring device including a pusher portion according to a sixth embodiment of the present invention, as viewed from the same position as FIG. 1.

FIG. 8 is a longitudinal cross-sectional view of a gas spring device including a pusher portion according to a seventh embodiment of the present invention, as viewed from the same position as FIG. 1.

9 is a longitudinal sectional view of a gas spring device including a piston portion, a piston rod portion, and a push rod portion according to an eighth embodiment of the present invention, as viewed from the same position as FIG. 1.

Hereinafter, a case where a gas spring device according to an embodiment of the present invention is applied to a backrest angle adjustment mechanism for adjusting the angle of a chair backrest will be described in detail with reference to the attached drawings. In the embodiment, the case where the mounting ring is arranged on the upper side and the piston rod portion is arranged on the lower side is illustrated, and the structure of each part will be described based on the upper position and the lower position. On the other hand, the gas spring device can also be arranged with the mounting ring on the lower side and the piston rod portion on the upper side, and can also be used in a horizontal position.

1 and 2 show a first embodiment of the present invention. In FIG. 1, a gas spring device 1 according to a first embodiment is configured to elastically support a backrest (not shown) of a chair, and the angle of the backrest can be adjusted. The gas spring device 1 is configured to include a cylinder block 2 described later, a piston portion 7, a piston rod portion 8, a communication path 9, and a push rod portion 12.

The cylinder block 2 is formed as a cylindrical body that constitutes a casing of the gas spring device 1. The upper end of the cylinder block 2 is closed in a gas-liquid-tight manner by a cover 2A. The cover 2A is provided with a mounting ring 3 for mounting the cylinder 2 to a fixing portion (not shown).

On the other hand, the rod guide 4 is caulked and fixed to the lower end side of the cylinder block 2. The rod guide 4 is used to slidably support the piston rod portion 8, and a sealing member 5 is provided on the upper side of the rod guide 4 to hermetically seal the piston rod portion 8 with the piston rod portion 8.

The free piston 6 is located on the upper side of the cylinder block 2 and is slidably inserted into the cylinder block 2. A gas chamber A is defined between the free piston 6 and the cover 2A, and a pressurized gas is sealed in the gas chamber A. In addition, the operating oil is sealed between the lower side of the free piston 6 and the sealing member 5.

The piston portion 7 is provided in the cylinder block 2. The piston portion 7 is formed into a cylindrical shape having a step, for example, by subjecting a metal material to a cutting process or the like. Specifically, the piston portion 7 is configured to include a thick-walled cylindrical partition portion 7A slidably inserted into the cylinder 2 in the axial direction, and a cylindrical shape extending downward from the center of the partition portion 7A.的 轴 部 7B。 The shaft portion 7B. The partition 7A divides the inside of the cylinder block 2 into two chambers: an upper oil chamber B located between the cylinder 2 and the free piston 6 and a lower oil chamber C located between the upper oil chamber B and the sealing member 5.

On the other hand, a small-diameter hole 7C extending in the axial direction to the shaft portion 7B and a large-diameter hole 7D extending in the axial direction are formed at the center of the axis of the partition 7A. Furthermore, a passage portion 7E is formed in the piston portion 7 to communicate the small-diameter hole 7C and the lower oil chamber C. One end of the passage portion 7E located on the inner diameter side of the piston portion 7 is opened to a portion above the small diameter hole 7C, and the other end located on the outer diameter side is opened to the outer peripheral surface of the shaft portion 7B. The small-diameter hole 7C of the piston portion 7 forms a valve seat portion that is opened and closed by a valve member 13 of a pusher portion 12 described later. The small-diameter hole 7C constitutes an insertion hole 10 described later, and the small-diameter hole 7C and the passage portion 7E constitute a communication path 9 described later.

The piston rod portion 8 is formed as a hollow rod-shaped body extending in the axial direction of the cylinder block 2. The piston rod portion 8 is, for example, a cylindrical body having a small diameter and a long shape, which is formed into a small diameter and a long shape by cutting or the like of a metal material. The upper end side of the piston rod portion 8 is a large-diameter hole 7D fixed to the piston portion 7 by caulking and fixed in the cylinder 2, thereby being integrated with the piston portion 7. On the other hand, the lower end side of the piston rod portion 8 extends to the outside of the cylinder block 2 through the seal member 5 and the rod guide 4.

The piston rod portion 8 is formed with a rod hole 8A located at the center of the shaft. Further, the piston rod portion 8 is formed with an enlarged diameter accommodation portion 8B located at an end portion above the rod hole 8A and configured to receive a bearing 11 and the like described later. On the other hand, a screw portion 8C is formed on the lower end side of the piston rod portion 8 for mounting the piston rod portion 8 on another fixing portion (not shown).

The communication path 9 communicates the upper oil chamber B and the lower oil chamber C formed in the cylinder block 2. This communication path 9 is formed by the upper portion of the small-diameter hole 7C of the piston portion 7 and the passage portion 7E.

The insertion hole 10 is provided so as to penetrate the piston portion 7 and the piston rod portion 8 in the axial direction. The insertion hole 10 is composed of a small-diameter hole 7C of the piston portion 7 and a rod hole 8A of the piston rod portion 8. The insertion hole 10 is for inserting the pusher part 12 mentioned later so that it may move to an axial direction.

The bearing 11 is inserted into the small-diameter hole 7C of the piston portion 7. The bearing 11 is a cylindrical sliding bearing made of a material having self-lubricity. The bearing 11 supports a lower portion of the valve member 13 constituting the push rod portion 12 so as to be movable in the axial direction.

Next, the structure of the putter part 12 which is the 1st Embodiment of the special part of this invention is demonstrated.

The pusher portion 12 allows the communication path 9 to be communicated (open) or blocked (closed) between the upper oil chamber B and the lower oil chamber C by an external operation. The push rod portion 12 is composed of a valve member 13, a rod member 14, and a cover member 15 described later.

The valve member 13 is disposed throughout the small-diameter hole 7C of the piston portion 7 and the rod hole 8A (the enlarged-diameter receiving portion 8B) of the piston rod portion 8. The valve structure Reference numeral 13 constitutes a stem body together with a stem member 14 described later, and constitutes a valve portion. The valve member 13 is formed as a metal rod-shaped body having a step, and is inserted into the center positions of the piston portion 7 and the piston rod portion 8 so as to be movable in the axial direction.

A reduced diameter portion 13A is provided on the valve member 13 on the upper side so as to face the passage portion 7E. The reduced-diameter portion 13A can be brought into liquid-tight sliding contact with the small-diameter hole 7C of the piston portion 7 by making the outer peripheral surfaces of the valve member 13 located above and below the reduced-diameter portion 13A a small-diameter hole. A circular path 13B is formed between 7C. Here, the upper end surface of the valve member 13 receives the pressure in the upper oil chamber B, and is stored in the direction of the arrow a (downward) by the pressure difference between the upper end surface and the end surface under the atmospheric pressure.

In addition, the valve member 13 and the rod member 14 are pushed together (upward) by a predetermined size in the direction of the arrow b, so that the annular passage 13B is communicated with the upper oil chamber B. In this manner, in a state where the upper oil chamber B and the lower oil chamber C are communicated through the annular passage 13B, the piston portion 7 can be freely moved in the axial direction with respect to the cylinder block 2. In this way, the protruding size of the piston rod portion 8 with respect to the cylinder block 2, that is, the angle of the backrest can be adjusted.

The stem member 14 constitutes a stem body together with the valve member 13 and is movably inserted into the insertion hole 10 in the axial direction together with the valve member 13. Like the valve member 13, the rod member 14 is formed as a metal rod-shaped body having a step. The upper end surface of the rod member 14 on the piston portion 7 side is in contact with the lower end surface of the valve member 13.

On the other hand, as shown in FIG. 2, the lower end of the rod member 14 on the side opposite to the piston portion 7 side is straight on the lower side of the segment portion 14A. The diameter is reduced, and this portion becomes the small-diameter shaft portion 14B. The small-diameter shaft portion 14B becomes a pillar for mounting a cover member 15 described later, and is pressed into a mounting hole 15B of the cover member 15.

The cover member 15 is provided at a lower end portion of the rod member 14 on the side opposite to the piston portion 7 side. The cover member 15 prevents lateral displacement (radial displacement) of the lower portion of the pusher portion 12 when the cover member 15 is pushed from the lower side by an external lever 16 to be described later. The cover member 15 is formed into a bottomed cylindrical shape from a resin material such as graphite, polytetrafluoroethylene (PTFE), molybdenum disulfide, or tungsten disulfide, for example, so as to protrude from the piston rod portion 8. Attach to the lever member 14. More specifically, the lower end portion 15A of the lid member 15 has a projectile shape having a convex spherical shape.

The outer diameter size (diameter size) of the cover member 15 is set to be approximately the same as the outer diameter size of the lever member 14, and is preferably a size slightly larger than the outer diameter size of the lever member 14. When the outer diameter of the cover member 15 is larger than the outer diameter of the rod member 14, the cover member 15 made of a resin material having self-lubricity can be made before the metal rod member 14. Contact rod hole 8A.

A mounting hole 15B is formed in the cover member 15 so as to open upward. The small-diameter shaft portion 14B of the rod member 14 is pressed into the mounting hole 15B. Furthermore, since the lower end portion 15A of the cover member 15 has a convex spherical shape, the contact state with the external lever 16 can always be maintained constant.

As shown in FIG. 1, one end portion of the external lever 16 is rotatably attached to the aforementioned other fixing portion through a pin 16A. Therefore, the outer lever 16 uses the pin 16A as a fulcrum and turns the other end portion in the direction of the arrow c. As a result, the pusher portion 12 can be pushed in the direction of arrow b. In this state, the protruding size (amount of expansion and contraction) of the piston rod portion 8 with respect to the cylinder block 2 can be adjusted.

The gas spring device 1 of the first embodiment is configured as described above, and the operation of the gas spring device 1 will be described next.

The external lever 16 is rotated in the direction of arrow c, and the pusher portion 12 is moved in the direction of arrow b. Thereby, the pusher portion 12 allows the annular passage 13B of the valve member 13 to reach the upper oil chamber B, and allows the upper oil chamber B and the lower oil chamber C to communicate. In this state, since the working oil is freely reciprocated between the upper oil chamber B and the lower oil chamber C, the movement of the piston portion 7 with respect to the cylinder block 2 in the axial direction is free. Therefore, by pushing the cylinder block 2 in the direction of the arrow a, the piston rod portion 8 can be pushed into the cylinder block 2 to be reduced in size. On the other hand, by extending the cylinder block 2 in the direction of the arrow b, the piston rod portion 8 can be extended from the cylinder block 2.

When the extension position of the piston rod portion 8 with respect to the cylinder block 2 is determined, the pushing of the external lever 16 to the push rod portion 12 is released. Thereby, the spaces between the oil chambers B and C are blocked, and the position of the piston rod portion 8 can be fixed.

Here, when the external lever 16 is rotated to push the pusher portion 12, the external lever 16 does not contact the pusher portion 12 at a right angle, and the external lever 16 contacts the pusher at an angle α larger than the right angle. The lower portion of the shaft portion 12. The angle α is, for example, about 145 degrees. In this case, for the pusher portion 12, a lateral force generated by the external lever 16 abutting obliquely, that is, a force that pushes the pusher portion 12 in the radial direction (direction of arrow d). using. Therefore, the rod member 14 constituting the push rod portion 12 is tightly pressed against the inner peripheral surface of the rod hole 8A of the piston rod portion 8. In this way, the sliding resistance when the pusher portion 12 moves in the axial direction increases, and there is a possibility that the pushing operability of the pusher portion 12 is deteriorated.

However, according to the first embodiment, the lower end portion of the rod member 14 having the end portion opposite to the piston portion 7 side of the push rod portion 12 of the valve member 13 is made of a resin member made of a cover member 15. The valve member 13 is formed to open and close a communication path 9 for communicating the upper oil chamber B and the lower oil chamber C formed in the cylinder block 2.

In this way, the resin material forming the cover member 15 is a self-lubricating resin material, which can slide the cover member 15 relative to the external lever 16 and can suppress the sliding resistance caused by the lateral force acting on the push rod portion 12 .

As a result, the sliding resistance of the push rod portion 12 with respect to the piston rod portion 8 becomes small, and scuffing between the piston rod portion 8 and the push rod portion 12 can be prevented, and the operability when the push rod portion 12 is pushed becomes good. .

In addition, the piston portion 7 and the piston rod portion 8 are provided with insertion holes 10 penetrating in the axial direction. Further, the push rod portion 12 includes a rod body having a valve member 13 inserted in the insertion hole 10 so as to be movable in the axial direction, and a side opposite to the piston portion 7 of the rod member 14 constituting the rod body. A cover member 15 made of a resin material is provided at an end portion thereof in a state protruding from the piston rod portion 8. Therefore, when the cover member 15 is worn or damaged, it is easy to replace it with a new cover member 15.

On the other hand, the cover member 15 is configured to be fitted by pressing its mounting hole 15B into the small-diameter shaft portion 14B of the lever member 14. In this way, the cover member 15 can be attached to the lever member 14 with a simple structure.

In addition, since the lower end portion 15A of the end portion of the cover member 15 opposite to the piston side is formed into a convex spherical shape, the contact state of the lower end portion 15A of the cover member 15 with the external lever 16 is always maintained constant. In this way, the positioning operation related to the mounting direction of the cover member 15 can be omitted, and the mounting operation can be simplified. In addition, the cover member 15 can be processed separately, and the convex spherical surface processing can be easily performed, and the cost can be reduced.

The outer diameter size (diameter size) of the cover member 15 is set to be approximately the same size as or slightly larger than the outer diameter size of the rod member 14. In this way, the cover member 15 can be brought into sliding contact with the rod hole 8A, and the push rod portion 12 can be smoothly moved in the insertion hole 10.

Next, Fig. 3 shows a second embodiment of the present invention. A feature of this embodiment is that a sliding bearing is arranged at a portion on the inner peripheral side of the piston rod portion that slides with the push rod portion. In the second embodiment, the same components as those in the first embodiment are assigned the same reference numerals, and descriptions thereof are omitted.

In FIG. 3, the piston rod portion 21 of the second embodiment is substantially the same as the piston rod portion 8 of the first embodiment described above. It is formed as a hollow rod-shaped body made of a metal material, and is formed at the center of its axis. A rod hole 21A and an enlarged-diameter accommodating portion (not shown). Further, a threaded portion 21B is formed on the outer peripheral side of the lower end side of the piston rod portion 21. However, the piston rod portion 21 of the second embodiment is different from the piston rod portion 8 of the first embodiment. This is to increase the diameter of the lower end side of the rod hole 21A to form a bearing receiving portion 21C.

The sliding bearing 22 of the second embodiment is inserted into, for example, press-fitting means such as a portion that slides with the push rod portion 12 on the inner peripheral side of the piston rod portion 21, that is, the bearing housing portion 21C of the piston rod portion 21 . The sliding bearing 22 is formed into a cylindrical shape from, for example, a metal material or a resin material having self-lubricity, and the cover member 15 is slidably supported in the axial direction by its inner peripheral surface.

As described above, the second embodiment configured as described above can also obtain substantially the same effects as the first embodiment. In particular, according to the second embodiment, a sliding bearing 22 having a self-lubricating property is provided at a portion on the inner peripheral side of the piston rod portion 21 that slides with the push rod portion 12. Thereby, the sliding bearing 22 supports the cover member 15 so that it can slide in an axial direction, and the operability of the pusher part 12 can be made more favorable.

Next, Fig. 4 shows a third embodiment of the present invention. A feature of this embodiment is that a sliding bearing is arranged on a portion of the inner peripheral side of the piston rod portion that slides with the push rod portion. In addition, the cover member is screwed to the pusher portion for mounting. In the third embodiment, the same reference numerals are given to the same constituent elements as in the first embodiment described above, and descriptions thereof are omitted.

In FIG. 4, the piston rod portion 31 of the third embodiment is the same as the piston rod portion 21 of the second embodiment, and includes a rod hole 31A, an enlarged diameter receiving portion (not shown), a screw portion 31B, and a bearing. Containment Department 31C. A sliding bearing 32 made of a metal material or a resin material having self-lubricity is inserted into the bearing housing portion 31C.

The rod member 33 according to the third embodiment is substantially the same as the rod member 14 according to the first embodiment, and is a rod-shaped body made of metal and forming a part of the rod body. However, the lever member 33 of the third embodiment is different from the lever member 14 of the first embodiment in that a step portion 33A and a screw shaft 33B are formed at the lower end portion.

The cover member 34 of the third embodiment is substantially the same as the cover member 15 of the first embodiment, and is provided at the lower end portion of the lever member 33. The cover member 34 is formed in a bottomed cylindrical shape from a self-lubricating resin material, and the lower end portion 34A is formed in a convex spherical shape. Furthermore, a mounting hole 34B is formed in the cover member 34 so as to open upward. However, the cover member 34 of the third embodiment is different from the cover member 15 of the first embodiment in that the mounting hole 34B is formed as a screw hole to be screwed with the screw shaft 33B of the lever member 33.

In this way, the third embodiment configured as described above can also obtain substantially the same effects as the first and second embodiments described above. In particular, according to the third embodiment, the cover member 34 can be easily attached to the lever member 33 by screwing the mounting hole 34B formed by the female screw on the screw shaft 33B of the lever member 33. In addition, the cover member 34 can be easily replaced.

Next, Fig. 5 shows a fourth embodiment of the present invention. A feature of this embodiment is that a sliding bearing is arranged on a portion of the inner peripheral side of the piston rod portion that slides with the push rod portion. The pusher portion is configured not to reduce the diameter of the lower end portion, but to attach a cover member to the lower end portion. In the fourth embodiment, the same reference numerals are given to the same constituent elements as those in the first embodiment, and descriptions thereof are omitted.

In FIG. 5, the piston rod portion 41 of the fourth embodiment is substantially the same as the piston rod portion 21 of the second embodiment described above, and includes a rod hole 41A, an enlarged diameter receiving portion (not shown), and a threaded portion 41B. And bearing accommodation 41C. However, the piston rod portion 41 of the fourth embodiment is different from the piston rod portion 21 of the second embodiment in that the bearing housing portion 41C is arranged in order to avoid interference between the sliding bearing 42 and the cover member 44 described below in the axial direction. In the interior. Along with this, a cover insertion hole 41D is formed in the piston rod portion 41 with a diameter larger than that of the rod hole 41A.

The sliding bearing 42 according to the fourth embodiment is similar to the sliding bearing 22 according to the second embodiment, and is made of a metal material or a resin material having self-lubricating properties, and is inserted into a bearing receiving portion 41C of the piston rod portion 41.

The rod member 43 according to the fourth embodiment is substantially the same as the rod member 14 according to the first embodiment, and is formed as a metal rod-shaped body having a step, which constitutes a part of the rod body. However, the lever member 33 of the fourth embodiment is different from the lever member 14 of the first embodiment in that a step portion and a small-diameter shaft portion are not formed at the lower end portion.

The cover member 44 of the fourth embodiment is substantially the same as the cover member 15 of the first embodiment, and is provided at the lower end portion of the lever member 43. The cover member 44 is formed in a bottomed cylindrical shape from a resin material having self-lubricity, and the lower end portion 44A is formed in a convex spherical shape. In addition, a mounting hole 44B is formed in the cover member 44 so as to open upward.

However, the cover member 44 of the fourth embodiment is different from the cover member 15 of the first embodiment in that it is different from the cover member 15 of the first embodiment. The cover member 15 is formed to have a larger diameter. Specifically, the inner diameter size of the mounting hole 44B of the cover member 44 is set to a size in which the lever member 33 is inserted. Further, the cover member 44 is inserted into the cover insertion hole 41D of the piston rod portion 41 so as to form a small gap.

In this way, the fourth embodiment configured as described above can also obtain substantially the same functions and effects as those of the foregoing embodiments. In particular, according to the fourth embodiment, by forming the cover member 44 to have a large diameter, the cover member 44 can be attached without performing a step forming process on the lower end portion of the lever member 43. In this way, the processing cost for providing the cover member 44 can be reduced.

Next, Fig. 6 shows a fifth embodiment of the present invention. A feature of this embodiment is that a sliding bearing is arranged on a portion of the inner peripheral side of the piston rod portion that slides with the push rod portion. In addition, the cover member is attached to a pin provided in the pusher portion and is attached. In the fifth embodiment, the same components as those in the first embodiment are assigned the same reference numerals, and descriptions thereof are omitted.

In FIG. 6, the piston rod portion 51 of the fifth embodiment is similar to the piston rod portion 21 of the second embodiment described above, and includes a rod hole 51A, an enlarged diameter receiving portion (not shown), a threaded portion 51B, and Bearing housing 51C. A sliding bearing 52 made of a self-lubricating metal material or resin material is inserted into the bearing accommodating portion 51C.

The rod member 53 according to the fifth embodiment is substantially the same as the rod member 14 according to the first embodiment, and is formed as a metal rod-shaped body having a step, which constitutes a part of the rod body. Further, a step portion 53A and a small-diameter shaft portion 53B are provided at the lower end portion of the lever member 53. However, the fifth embodiment The lever member 53 is different from the lever member 14 of the first embodiment in that an engagement pin 53C is provided on the small-diameter shaft portion 53B so as to protrude outward in the radial direction.

The cover member 54 of the fifth embodiment is substantially the same as the cover member 15 of the first embodiment, and is provided at the lower end portion of the lever member 53. The cover member 54 is formed in a bottomed cylindrical shape from a resin material having self-lubricity, and the lower end portion 54A is formed in a convex spherical shape. Furthermore, a mounting hole 54B is formed in the cover member 54 so as to open upward. However, the cover member 54 according to the fifth embodiment is different from the cover member 15 according to the first embodiment in that the inner peripheral surface of the mounting hole 54B is formed with a latch that engages with the engaging pin 53C of the lever member 53.合 槽 54C.

Here, the engaging groove 54C of the cover member 54 is a substantially L-shaped groove formed so as to extend from the opening end of the mounting hole 54B in the axial direction and bent in the circumferential direction. Therefore, the cover member 54 is such that the small-diameter shaft portion 53B is inserted into the mounting hole 54B so that the engaging pin 53C of the rod member 53 enters along the engaging groove 54C. Spin. In this way, the engaging groove 54C of the lid member 54 and the engaging pin 53C of the lever member 53 can be engaged, and the lid member 54 can be attached to the lever member 53 in a state of preventing the lid member 54 from being separated.

In this way, the fifth embodiment configured as described above can also obtain substantially the same effects as those of the foregoing embodiments. In particular, according to the fifth embodiment, the cover member 54 can be easily attached to the lever member 53 by engaging the engaging pin 53C of the lever member 53 in the engaging groove 54C of the lid member 54. In addition, the cover member 54 can be easily replaced.

Next, Fig. 7 shows a sixth embodiment of the present invention. A feature of this embodiment is that the lever member of the putter portion is formed of a resin material. In the sixth embodiment, the same components as those in the first embodiment are assigned the same reference numerals, and descriptions thereof are omitted.

In FIG. 7, the pusher portion 61 of the sixth embodiment is composed of a valve member 13 described in the first embodiment and a rod member 62 described later.

The rod member 62 of the sixth embodiment is formed as a rod-shaped body made of, for example, a resin material having self-lubricity. The rod member 62 is disposed so as to be movable in the axial direction within the rod hole 8A of the piston rod portion 8. The upper end surface of the stem member 62 is in contact with the lower end surface of the valve member 13. On the other hand, the lower end side of the lever member 62 protrudes from the lever hole 8A, and the lower end portion 62A is formed in a convex spherical shape. The lower end portion 62A is in contact with the external lever 16.

In this manner, the sixth embodiment configured as described above can also obtain substantially the same effects as those of the aforementioned embodiments. In particular, according to the sixth embodiment, the rod member 62 composed of a self-lubricating resin material can slide smoothly with respect to the piston rod portion 8, and the push rod portion 61 can operate well. In addition, the number of parts can be reduced.

Next, Fig. 8 shows a seventh embodiment of the present invention. A feature of this embodiment is that the entire length of the push rod portion from the end portion opposite to the piston portion side to the end portion on the piston portion side is formed of a resin material. In the seventh embodiment, the same components as those in the first embodiment are assigned the same reference numerals, and descriptions thereof are omitted.

In FIG. 8, the putter portion 71 of the seventh embodiment is in the slave position. The entire length from the end portion on the upper side opposite to the piston portion 7 side to the end portion on the lower side of the piston portion 7 side, that is, the entire length through the insertion hole 10 is formed as a single member. The pusher portion 71 is formed into a rod-shaped body having a step, for example, from a resin material having self-lubricity. The upper portion of the pusher portion 71 is a valve portion 71A that opens and closes the communication path 9 in the small-diameter hole 7C of the piston portion 7. On the other hand, the lower end portion 71B of the pusher portion 71 protrudes from the insertion hole 10 into a convex spherical shape, and abuts against the external lever 16.

In this manner, the seventh embodiment configured as described above can also obtain substantially the same functions and effects as those of the foregoing embodiments. In particular, according to the seventh embodiment, the entire length of the pusher portion 71 from the end portion on the side opposite to the piston portion 7 to the end portion on the piston portion 7 side is formed of a resin material. Therefore, the push rod portion 71 can be slid smoothly with respect to the piston rod portion 8 to improve the operability. In addition, the number of parts can be further reduced.

Next, Fig. 9 shows an eighth embodiment of the present invention. This embodiment is characterized in that the piston portion and the piston rod portion are formed as a single member, and the entire length of the push rod portion is formed of a resin material. In the eighth embodiment, the same components as those in the first embodiment are assigned the same reference numerals, and descriptions thereof are omitted.

In FIG. 9, the piston-rod member 81 of the eighth embodiment is formed of a piston portion 82 and a piston rod portion 83. The piston-rod member 81 is formed integrally with the piston portion 82 and the piston rod portion 83, for example, by using a sintered metal body.

The piston-rod member 81 is provided with a piston portion 82 and a piston Through-hole 84 of the rod portion 83. A passage portion 82A is formed in the piston portion 82 so as to communicate with the insertion hole 84. Further, a threaded portion 83A is formed at a lower portion of the piston rod portion 83 for attaching the piston rod portion 83 to another fixing portion (not shown).

The overall length of the pusher portion 85 of the eighth embodiment from the end portion on the upper side opposite to the piston portion 82 side to the end portion on the lower side of the piston portion 82 side, that is, the entire penetration hole 84 The length is formed as a single member. The pusher portion 85 is formed into a rod-shaped body having a step, for example, from a resin material having self-lubricity. The upper part of the pusher part 85 becomes the valve part 85A. On the other hand, the lower end portion 85B of the pusher portion 85 protrudes from the insertion hole 84 and is formed into a convex spherical shape, and abuts against the external lever 16.

In this way, the eighth embodiment configured as described above can also obtain substantially the same effects as those of the aforementioned embodiments. In particular, according to the eighth embodiment, the piston portion 82 and the piston rod portion 83 are formed into a single piston-rod member 81 using a sintering process. In this way, the number of parts can be reduced and assembly workability and the like can be improved. In addition, the integrally formed piston-rod member 81 can reduce the axial dimension, so that the overall length of the gas spring device 1 can be shortened.

The entire length of the pusher portion 85 from the end portion on the side opposite to the piston portion 82 to the end portion on the piston portion 82 side is formed of a resin material. Therefore, the pusher portion 85 can be slid smoothly in the insertion hole 84 to improve the operability. In addition, the number of parts can be reduced.

Also in each embodiment, the gas spring device 1 is described as an example. Used in the case of a backrest angle adjustment mechanism for adjusting the angle of the backrest of a chair. However, the present invention is not limited to this. For example, the gas spring device 1 may be configured to use a height adjustment mechanism for adjusting the height of the seat portion of the chair. The gas spring device 1 can also be used in a bed or the like other than a chair.

As the gas spring device based on the embodiment described above, for example, the following aspects can be considered.

As a first aspect of the gas spring device, a cylinder body, a piston portion, a piston rod portion, a communication path, and a pusher portion are provided. The cylinder body is filled with a pressurized gas inside, and the piston portion is slidably inserted. The cylinder body is divided into two chambers; one end of the piston rod portion is connected to the piston portion, and the other end extends to the outside of the cylinder body; the communication path is the aforementioned 2 formed in the cylinder body. The push rod portion is provided with a valve portion that opens and closes the communication path; the push rod portion is operated from outside to open the communication path, and the axial length of the piston rod portion with respect to the cylinder can be adjusted, The feature is that at least the end portion on the opposite side of the plunger portion from the piston portion side is formed using a resin material.

As a second aspect, in the first aspect, a sliding bearing is arranged at a position on the inner peripheral side of the piston rod portion that slides with the push rod portion.

As a third aspect, in the first aspect, the piston portion and the piston rod portion are provided with an insertion hole penetrating in the axial direction, and the push rod portion includes: movably inserted into the insertion hole in the axial direction. A rod body having a through hole and having the valve portion, and on the side of the rod body and the piston portion, A cover member made of a resin material is provided at an end portion on the opposite side so as to protrude from the piston rod portion.

As a fourth aspect, in the first aspect, the entire length of the pusher portion from the end portion on the side opposite to the piston portion side to the end portion on the piston portion side is formed of a resin material.

As a fifth aspect, in the third aspect, an end portion of the cover member has a convex spherical shape.

As a sixth aspect, in the third to fourth aspects, the outer diameter of the cover member is set to be the same as or slightly larger than the outer diameter of the rod body.

As a seventh aspect, in the third aspect, the piston portion and the piston rod portion are formed of a single member.

1‧‧‧ Gas Spring Device

2‧‧‧cylinder block

2A‧‧‧ Cover

3‧‧‧Mounting ring

4‧‧‧ Rod Guide

5‧‧‧sealing member

6‧‧‧ free piston

7‧‧‧Piston

7A‧‧‧ Division

7B‧‧‧Shaft

7C‧‧‧Small diameter hole

7D‧‧‧Large diameter hole

7E‧‧‧Access Department

8‧‧‧Piston rod

8A‧‧‧ Rod hole

8B‧‧‧Expansion Containment Department

8C‧‧‧Thread

9‧‧‧ Link Road

10‧‧‧Plug-in hole

11‧‧‧bearing

12‧‧‧Putter

13‧‧‧Valve member (valve part, stem body)

13A‧‧‧ Reduced diameter

13B‧‧‧Circle

14‧‧‧ Rod member (rod body)

14A‧‧‧section

14B‧‧‧Mounting holes

15‧‧‧ cover member

15A‧‧‧ lower end

15B‧‧‧Mounting hole

16‧‧‧External leverage

16A‧‧‧pin

A‧‧‧Gas chamber

B‧‧‧ Upper side oil chamber

C‧‧‧ Lower side oil chamber

Claims (7)

A gas spring device includes a cylinder body, a piston portion, a piston rod portion, a communication path, and a push rod portion. The cylinder body is filled with a pressurized gas inside; the piston portion is slidably inserted into the cylinder body, and The cylinder body is divided into two chambers; one end of the piston rod part is connected to the piston part and the other end extends to the outside of the cylinder body; the communication path communicates the two chambers formed in the cylinder body; the The pusher portion includes a valve portion that opens and closes the communication path. The pusher portion is operated from outside to open the communication path, and the axial length of the piston rod portion with respect to the cylinder can be adjusted. Among the pusher portions, at least the end portion opposite to the piston portion side is formed using a resin material. The gas spring device according to claim 1, wherein a sliding bearing is disposed on a portion of the inner peripheral side of the piston rod portion that slides with the push rod portion. The gas spring device according to claim 1 or 2, wherein the piston portion and the piston rod portion are provided with insertion holes penetrating in the axial direction, and the push rod portion includes: movably inserted in the axial direction and inserted in the axial direction A stem body having a valve portion inserted through the hole, and A cover member made of a resin material is provided at an end portion of the rod body opposite to the piston portion side in a state protruding from the piston rod portion. The gas spring device according to claim 1 or 2, wherein the entire length of the push rod portion from the end portion on the side opposite to the piston portion side to the end portion on the piston portion side is formed of a resin material. The gas spring device according to claim 3, wherein an end portion of the cover member has a convex spherical shape. The gas spring device according to claim 3 or 4, wherein the outer diameter size of the cover member is set to be the same as or slightly larger than the outer diameter size of the rod body. The gas spring device according to claim 3, wherein the piston portion and the piston rod portion are formed of a single member.