JP4726057B2 - gas spring - Google Patents

Description

  The present invention relates to a gas spring used for, for example, a flip-up type rear window or rear door of an automobile or the like, or a smoke exhaust window, and more particularly to a dust seal mounting structure.

  Conventionally, as this type of gas spring, the one shown in Patent Document 1 can be exemplified.

  That is, as shown in FIG. 7, a retainer 12 that abuts the piston 3 inside the cylinder 2 and restricts the maximum extension position, and is integrated with the opening end of the cylinder 2 from the piston 3 at a predetermined distance from the retainer 12. The bearings 9 for guiding the piston rods 4 extending in a fixed manner are respectively fixed.

  A packing 14 is interposed inside the cylinder 2 between the bearing 9 and the retainer 12, and the inner lip 15 of the outer periphery of the packing 14 is used for the inner peripheral surface of the cylinder 2. The inner lip 16 is slidably pressed against the outer peripheral surface of the piston rod 4 using the gas pressure of the cylinder 2.

  Also, in order to prevent external dust from entering the inside of the cylinder 2 from the protruding end side of the piston rod 4 in the cylinder 2 in advance on the cylinder opening side of the bearing 9 (referring to the left side in FIG. 7). The dust seal 10a made of an elastic material having a sealing function is provided so as to overlap with the bearing 9, and these are attached by bending the opening end of the cylinder 2 inward and performing a crimping process 11.

  However, when the dust seal 10 is fixed to the opening end of the cylinder 2 on the projecting end side of the piston 3 so as to overlap with the bearing 9, the dust seal 10 a is formed of an elastic material. When the pressure for 11 is insufficient, the clamping force of the lip 19 of the dust seal 10a against the outer peripheral surface of the piston rod 4 is insufficient. Conversely, when the pressure is excessively applied, the mouth of the lip 19 opens and the original rod as the dust seal 10a is opened. The sealing function cannot be achieved, and dust enters the cylinder 2 from the outside.

  In order to solve such problems, a structure of the dust seal 10 shown in FIG. 8 has been proposed.

  That is, the dust seal 10 has a base 17 made of a ring-shaped disk made of a hard material, and a lip 19 made of an elastic material that performs the original rod seal function in the central portion leaving the crimping portion 18 on the outer peripheral portion of the base 17. It was formed by integrally bonding.

  In this way, even if the tightening force of the caulking process 11 applied to the open end of the cylinder 2 is excessive or insufficient, the base 17 of the dust seal 10 is not deformed. The lip 19 of the dust seal 10 made of elastic material does not deform.

Accordingly, the dust seal 10 is always brought into contact with the piston rod 4 with a predetermined tightening force regardless of the excess or deficiency of the tightening force when the base 17 is subjected to the caulking process 11, and dust is externally introduced into the cylinder 2. Can be prevented from entering.
Japanese Patent Laid-Open No. 2002-115739 (FIGS. 1 and 2)

  The gas spring having the above-described structure is not particularly problematic, but the following problems may be considered.

  That is, this type of gas spring has different scraping performance required for the dust seal depending on the place of use.

  For example, when used as a gas spring for flue gas in buildings where dust etc. are likely to adhere, high dust scraping performance is required, but when used as a gas spring attached to the trunk of an automobile However, the dust scraping performance is not required as in the above building.

  Therefore, even if the gas spring has the same gas pressure and maximum extension length, it is necessary to design and install a dedicated dust seal that has different scraping performance depending on the conditions in which it is used. In the conventional structure that is integrated with the bearing integrally with the bearing, the assembled gas spring is dedicated for a specific purpose, and there is a problem that it is not versatile.

  In addition, even if a gas spring is being used under specific operating conditions, when replacing it with a dust seal with a different scraping performance due to environmental changes or aging of the dust seal, the dust seal is integrated with the bearing in the conventional structure described above. Since it is incorporated in the opening of the cylinder, there is a problem that only the dust seal cannot be easily replaced.

  Accordingly, an object of the present invention is to provide a gas spring having a versatile structure in which the dust seal can be easily changed depending on the conditions of use.

In order to achieve the above object, the present invention provides a retainer that abuts a piston inside a cylinder and restricts the maximum extension position, and a bearing that guides a piston rod to an opening end of the cylinder at a predetermined distance from the retainer. In the gas spring with a packing that prevents the pressure gas inside the cylinder from leaking to the outside by slidingly contacting the piston rod between the retainer and the bearing, the opening of the cylinder is formed. A covering member is provided, a dust seal is provided on the covering member to prevent dust from entering the cylinder by sliding contact with the piston rod, and the retainer caulks the cylinder inwardly from the outside to the cylinder. It is fixed to the cylinder and is opposed to the cylinder caulking groove formed by the caulking process. The inside seal member of the covering member is provided, it is characterized in that it has sealing between the covering member and the cylinder.

According to the present invention, the gas spring can be assembled and divided into the covering member having the dust seal and the cylinder body in which the retainer, the packing and the bearing are mounted in the cylinder. In addition, if a plurality of types of covering members differing only in the performance of the dust seal are prepared, a gas spring having a different performance in the dust seal can be easily manufactured by appropriately combining them.

In addition, even when using a gas spring that is in use, if you want to replace it with a dust seal with different performance, the dust seal is not integrated into the opening of the cylinder integrally with the bearing as in the conventional structure. can do.
Further, since the sealing member provided on the inner peripheral surface of the covering member is fitted in the caulking groove of the cylinder, the inner peripheral surface of the covering member and the outer peripheral surface of the cylinder are sealed. It is possible to reliably prevent water and the like from entering between the outer peripheral surface of the cylinder and the inner peripheral surface of the covering member.

  Hereinafter, an embodiment in which the present invention is embodied in a gas spring used for a back door of an automobile will be described with reference to the drawings.

As shown in FIG. 1, the gas spring 1 a includes a cylinder 2, a retainer 12 that is fixed to the inside of the cylinder 2 and abuts against the piston 3 to restrict its maximum extension position, and maintains a predetermined distance from the retainer 12. The bearing 9 is disposed at the open end of the cylinder 2 (referred to as the left end in FIG. 1) and guides the piston rod 4, and is disposed between the retainer 12 and the bearing 9 so as to be in sliding contact with the piston rod 4. 2 A packing 14 for preventing the pressure gas inside from leaking to the outside and a covering member for covering the opening of the cylinder 2 are provided. Dust enters the cylinder 2 by slidingly contacting the piston rod 4 on the covering member. the dust seal to prevent the provided partition the rod-side gas chamber R and the piston-side gas chamber P inside the cylinder 2 by the piston 3 These gas chamber R, P are communicated with each other through a throttle hole 5 bored piston 3 through.

  And a cover body 13 as a covering member of the present invention provided with a dust seal 10b for preventing dust from entering the cylinder 2.

  More specifically, the piston 3 that slides in the cylinder 2 is fixed to the base end of the piston rod 4 (referred to as the right end in FIG. 1).

A piston seal 3a is mounted on the outer peripheral surface of the piston 3, and the retainer 12 in the cylinder 2 is formed with a fitting groove 12a on the outer peripheral surface, and the cylinder 2 is caulked from the outside to the inside. Thus, the cylinder 2 is fitted into the fitting groove 12a by being deformed into a reduced diameter, and both are fixed.

  A caulking groove 2a is formed on the outer periphery of the cylinder by the caulking process described above, and an O-ring 27 (to be described later) is mounted in the caulking groove 2a.

  The bearing 9 is lightly press-fitted into the opening end of the cylinder 2 and is fixedly positioned and bent by bending the end portion inward and crimping.

  The packing 14 is disposed on the side opposite to the cylinder opening of the bearing 9 (referred to the right side in FIG. 1), and is made of a metal core 14a and an inner peripheral lip 16 formed integrally with the core 14a. And an outer peripheral lip 15.

  The outer peripheral lip 15 is pressed against the inner peripheral surface of the cylinder 2 by utilizing the gas pressure in the cylinder 2 to seal between them, and the inner peripheral lip 16 is similarly applied to the outer peripheral surface of the piston rod 4 on the cylinder 2. It is designed to seal between them by being pressed using the internal gas pressure.

  As shown in FIG. 2, the cover body 13 is formed in a cylindrical shape in which the opening of the cylinder 2 can be press-fitted into the inside, and the dust seal 10 b is formed on a portion of the cylinder 2 facing the protruding end of the piston rod 4. A mounting groove 21 is formed as a mounting portion for mounting, and a retaining portion 22 is formed on the cylinder opening side of the mounting groove 21 to prevent the dust seal 10b from coming off to the cylinder opening side. Yes.

  As shown in FIG. 3, the dust seal 10 b is formed of a base 24 having a rectangular cross section and a dust lip 25 protruding inward from the base 24, and the base 24 is fitted into the mounting groove 21. As a result, the dust seal 10b is fixed to the cover body 13, and the base 24 is brought into contact with the retaining portion 22 so that the dust seal 10b does not come out to the cylinder opening side.

A ring mounting groove 26 is formed on the inner peripheral surface of the cover body 13 that faces the caulking groove 2a, and an O-ring 27 ( see FIG. 1 ) as a seal member is attached to the ring mounting groove 26 . It has been.

  Accordingly, when the cover body 13 with the O-ring 27 attached to the ring attachment groove 26 is inserted into the cylinder 2, the O-ring 27 is attached to the caulking groove 2 a of the cylinder 2, so that the outer peripheral surface of the cylinder 2 And the inner peripheral surface of the cover body 13 are sealed.

  In order to assemble the gas spring 1a configured as described above, first, the retainer 12 is inserted into the cylinder 2 into which the piston 3 and the piston rod 4 are inserted, and the cylinder 2 is crimped from the outside to the inside to reduce the diameter. The cylinder 2 is fitted into the fitting groove 12a by being deformed into a shape, and both are fixed.

  Next, the bearing 9 and the packing 14 are lightly press-fitted into the cylinder 2 in this state, and the cylinder 2 is formed by positioning and fixing them by bending the open end of the cylinder 2 inward and crimping.

  Thereafter, by inserting the cover body 13 into the cylinder body, the gas spring 1a to which the dust seal 10b is attached is formed.

  At this time, the cover body 13 is positioned by the stepped portion 21a of the mounting groove 21 coming into contact with the bent portion 2b at the opening end of the cylinder 2, and the dust seal 10b is formed by the bent portion 2b and the retaining portion 22. As a result, the movement of the piston rod 4 in the axial direction is restricted and the positioning is fixed.

  In the gas spring 1a configured as described above, a plurality of types of gas springs having the same gas pressure and maximum extension length enclosed in the cylinder 2 and different only in the scraping performance of the dust seal 10b are manufactured. If a large number of cylinder bodies are manufactured in advance and a plurality of types of cover bodies 13 differing only in the dust seal 10b are prepared, gas springs having different scraping performance can be easily manufactured by combining them. Is possible.

  Therefore, the problem that there is no versatility as shown in the prior art is solved, and a gas spring having a versatile structure that can easily change the dust seal 10b according to the conditions of use can be provided.

  Further, even when the gas spring 1a in use is to be replaced with a dust seal 10b having a different scraping performance, the dust seal is not integrated into the opening of the cylinder integrally with the bearing as in the conventional structure. Can be easily replaced.

Further, the O-ring 27 provided on the inner peripheral surface of the cover body 13 is mounted in the caulking groove 2a provided to fix the retainer on the inner periphery of the cylinder 2, so that the inner peripheral surface of the cover body 13 and the cylinder 2 Since the outer peripheral surface of the cover 2 is sealed, a groove for mounting the O-ring 27 is not provided separately, and the bearing 9 portion is provided between the outer peripheral surface of the cylinder 2 on the side opposite to the cylinder opening and the inner peripheral surface of the cover body 13. Water and the like can be reliably prevented from entering.

  In addition, since the protruding end of the piston rod 4 of the cylinder 2 is covered with the dust seal 10b, it is possible to prevent the bent portion 2b of the opening end of the cylinder 2 and the bearing 9 from being exposed to the outside, and the appearance is improved. Intrusion of foreign matter into the part can be reliably prevented.

  In addition, this invention is not limited to the said embodiment, For example, it can also be changed as follows.

  1) In the present embodiment, the inner peripheral surface of the cover body 13 is directly press-fitted into the cylinder 2, but the present invention is not limited to this, and as shown in FIG. A plurality of press-fitting allowances 28 may be provided on the peripheral surface to improve the press-fitting strength.

  2) An inclined surface 29 as shown in FIG. 5 may be provided on the inner peripheral surface of the cover body 13 at the end opposite to the cylinder opening. If it carries out like this, the attachment property of the O-ring 27 with respect to the said attachment groove | channel 21 can be improved.

  3) In this embodiment, the length of the cover body 13 on the side opposite to the cylinder opening is set longer than that of the O-ring 27. However, the length is not limited to this, and as shown in FIG. The length may be set to approximately the same length as 27. In this way, it is possible to prevent water or the like from entering and accumulating between the outer peripheral surface of the cylinder 2 on the side opposite to the cylinder opening than the O-ring 27 and the inner peripheral surface of the cover body 13.

  4) In this embodiment, the O-ring 27 is provided on the inner peripheral surface of the cover body 13, but this is not always necessary, and the O-ring 27 is improved by improving the assembly accuracy of the cover body 13 and the cylinder 2. It may be unnecessary.

It is sectional drawing which shows the opening part side as a principal part of the gas spring which shows one embodiment of this invention. It is sectional drawing which shows the cover body of FIG. It is sectional drawing which shows the dust seal | sticker of FIG. 1, and shows only an upper side from a centerline. It is sectional drawing which shows the example of this invention, and shows the state which cut | disconnected the cover body shown in FIG. 2 in the direction orthogonal to a paper surface. It is sectional drawing of the cover body which shows another example of this invention. It is sectional drawing which shows the other example of this invention and shows the opening part side as a principal part of a gas spring. It is sectional drawing which shows the prior art of this invention and shows the opening part side as a principal part of a gas spring. It is sectional drawing which shows the other conventional example of this invention, and shows the opening part side as a principal part of a gas spring.

Explanation of symbols

2 Cylinder 2a Clamping groove 3 Piston 4 Piston rod 9 Bearing 10b Dust seal 12 Retainer 13 Cover body (covering member)
14 Packing 22 Mounting groove (Mounting part)
26 ring mounting groove
27 O-ring (seal member)

Claims (4)

A retainer that abuts the piston and regulates the maximum extension position inside the cylinder, and a bearing that guides the piston rod to the opening end of the cylinder at a predetermined distance from the retainer are fixed, respectively. In the gas spring having a packing that prevents the pressure gas inside the cylinder from leaking to the outside by slidingly contacting the piston rod, a covering member that covers the opening of the cylinder is provided, and the piston is attached to the covering member. A dust seal is provided that slides into contact with the rod and prevents dust from entering the cylinder, and the retainer is fixed to the cylinder by crimping the cylinder from the outside to the inside. A sealing member is provided inside the covering member facing the caulking groove of the formed cylinder, Gas spring, characterized in that a seal between the covering member and the cylinder.   The cover member is a cover body formed in a cylindrical shape, and an attachment portion for attaching the dust seal is formed in a portion of the cylinder facing the protruding end of the piston rod, and the dust seal is attached to the attachment portion. The gas spring according to 1. The gas spring according to claim 1 or 2, wherein a plurality of press-fitting allowances are provided inside the covering member, and the covering member is press-fitted and fixed to the cylinder through the press-fitting allowances . The ring mounting groove is formed in the inner peripheral surface which becomes an anti-cylinder opening end side of the said covering member , The seal member was provided in this ring mounting groove, and it sealed between the covering member and the cylinder. Gas spring.

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