JPS61266839A - Gas spring - Google Patents

Abstract

PURPOSE:To provide desired operating speed by operating a ratchet mechanism disposed in a piston from the outside of a piston rod to vary an orifice interconnecting two chambers. CONSTITUTION:A first cam member 19 is rotatably slidably inserted into a piston 4 and provided on one end with ratchet teeth 23. The first cam member 19 is rotated to open and close a plurality of orifices 15-18 affording communication between both chambers 13, 14. The ratchet teeth 23 is urged by a spring to engage a stopper 27 fixed to the piston 4. Also, a second cam member 30 is provided slidably not to be pivoted so that it disengages the first cam member 19 from the stopper 27 and can rotate said member 19 by a predetermined amount. When the first cam member 19 engages again the stopper 27, it is further rotated to occupy a predetermined position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas spring capable of varying the operating speed of a piston rod.

[Prior art]

For example, a gas spring is attached to the hatchback door of a passenger car. This gas spring is a piston with an orifice formed in the piston and a piston rod protruding outside the cylinder in a cylinder filled with gas.
A piston rod assembly is provided with a slidable piston rod assembly. For example, by attaching one end of the cylinder to the body of a passenger car and attaching the end of the piston rod to the hatchback door, the gas in the cylinder is released when the hatchback door is closed. When compressed and the hatchback door is opened, the pressure of the gas in the cylinder causes a piston rod to protrude from the cylinder, thereby urging the hatchback door to open.

By the way, it is desired that the hatch back door be closed quickly with little resistance, and that the hatch back door be opened slowly with little resistance.

Therefore, conventionally, a one-way valve has been provided in the gas spring to meet the above demand.

[Problem that the invention seeks to solve]

However, in such conventional gas springs, the control direction of the operating speed of the piston rod is limited to one direction, and the operating speed cannot be changed in two stages, for example, due to seasonal temperature changes. This may cause the gas pressure to change, making it impossible to operate the piston rod at the desired speed.

An object of the present invention is to provide a gas spring that eliminates the above-mentioned drawbacks of conventional gas springs.

[Means for solving problems]

In order to achieve the above object, the present invention has the following configuration. That is, in a gas spring in which a piston rod is urged in the axial direction of the cylinder by the pressure of gas sealed in the cylinder, the piston is provided with a plurality of orifice passages having different effective cross-sectional areas and communicating the front and rear chambers of the piston. a first cam member having ratchet teeth formed at one end to select a predetermined orifice passage from among the plurality of orifice passages; A collar is provided that is movable and engages with the ratchet teeth to prevent rotation of the first cam member, and further engages with the ratchet teeth to engage the first cam member and the stopper. A second cam member is provided to be movable in the axial direction of the cylinder for releasing the coupling and rotating the first cam member by a predetermined rotation angle.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 to 8. In FIG. 2, 1 is a gas spring, and a piston/piston rod assembly 3 is slidably fitted into a cylinder 2 of this gas spring 1. Further, gas is sealed inside the cylinder 2.

The piston/piston rod assembly 3 consists of a piston 4 and a piston rod 5, and the piston 4 consists of a head 6 that is tightly fitted into the cylinder 2 and a tail 7 that is formed to have a smaller diameter than the head 6. . The piston 4 also has a maximum diameter portion 8. as shown in FIG. Second large diameter portion9. Medium diameter portion 10.
A central hole consisting of a small diameter portion 11 is formed. A tubular piston rod 5 is tightly fitted into the maximum diameter portion 8 and is attached to the piston 4 by caulking the tail portion 7 of the piston 4. 12 is a seal ring.

Before and after the piston 4 in the cylinder 2, there is a front chamber of 13 degrees and a rear chamber of 1.
4 is formed.

The interior of the inner diameter portion 10 of the piston 4 and the rear chamber 14 are communicated through orifice passages 15, 16, 17, and 18 formed in the piston 4.

The orifice passages 15, 16, 17, 18 are formed at four equal positions in the circumferential direction of the piston 4, and the orifice 15
and the orifice 16 have the same diameter, and are formed to be oriented in one diameter direction of the piston 4, and the orifice 17
The and orifice 18 have the same diameter, which is smaller than the diameter of the orifice 15.16, and are formed in a diametrical direction perpendicular to the orifice 15.16. Note that these orifices 15
16 and 17.18 are formed obliquely to the axis of the cylinder 2, as shown in FIG.

Also, the small diameter portion 11 of the center hole of the piston 4. A first cam member 19 is rotatably fitted into the middle diameter portion 10 . This first cam member 19 has a cylindrical portion 20 and a flange portion 21.
The flange portion 21 has parallel side surfaces 21a, 21a spaced at the same interval as the outer diameter of the cylindrical portion 20, and arcuate surfaces 21b, 21b that are slidably and rotatably fitted into the middle diameter portion 10, and has a center portion. It has a protrusion 22 on. The cylindrical portion 20 is slidably and rotatably fitted into the small diameter portion 11, and ratchet teeth 23 are formed on the distal end surface of the cylindrical portion 20 at four equal positions in the circumferential direction.

A ring-shaped spring seat 25 having a fluid passage 24 in the center is fitted into and fixed to the second large diameter portion 9 of the piston 4 . A spring 26 is provided between one first cam member and the spring seat 25 to bias the first cam member 19 toward the piston rod.

Furthermore, grooves are formed in the diametrical direction at the end of the piston rod 5 on the first cam member side, and stoppers 27 and 27 are formed in these grooves.
is buried. The stopper 27 has teeth 2 that prevent rotation of the first cam member 19 when engaged with the ratchet teeth 23.
It has an engaging portion consisting of 7a.

Further, a second cam member 30 having an operating rod 29 is inserted into the piston rod 5 so as to be positioned on the axis of the cylinder 2 and movable in the axial direction of the cylinder 2 . Second
A ratchet tooth 32 that engages with the ratchet tooth 23 of the first cam member 19 is provided on the distal end surface of the head 31 of the cam member 30.
are formed at four equal positions in the circumferential direction. The tooth width of the ratchet teeth 32 is as shown in FIG.
The tooth width is slightly larger than 1/2 of the tooth width of the nine ratchet teeth 23. Note that the tooth width m27a of the stopper 27 is equal to the ratchet tooth 2 of the first cam member 19, as shown in the figure.
It is said to be approximately 1/2 of the tooth width of No. 3.

Further, a collar 33 is provided at a portion of the operating rod 29 near the head 31. A groove 34 is formed on the outer periphery of the head 31 along its axial direction, and a key-shaped groove 34 is provided in the groove 34 at a predetermined location on the inner peripheral surface of the inner hole of the piston rod 5 so as to face the groove 34. A rotation stopper 35 is fitted, thereby preventing rotation of the second cam member 30. Further, a spring 36 is provided between the collar 33 and the rotation stopper 35 for biasing the second cam member 30 away from the first cam member 19.

Next, the operation of the gas spring configured as described above will be explained.

As shown in FIG. 6, in a state where m27a of the stopper 27 is engaged with the ratchet teeth 23 of the first cam member 19, the operating rod 29 is moved toward the first cam member 19,
The ratchet teeth 32 of the second cam member 30 are engaged with the ratchet teeth 23 .

At this time, as shown in FIG. 4, the first cam member closes the orifice passage 15,16 and opens the orifice passage 17,18.

Next, the second cam member 30 is further inserted into the first cam member 1.
When pushed toward one side, as shown in FIG. 7, the ratchet teeth 23 are pushed by the non-rotating ratchet teeth 32, and the first cam member 19 is separated from the stopper 27 in the direction indicated by the dotted arrow A in the figure. Rotate 90 degrees to Therefore, at this time,
As shown in FIG. 5, the first cam member 19 opens orifice 15.16 and closes orifice 17.18. If the gas spring 1 is operated in this state, the resistance of the gas passing through the orifice will be lower than in the states shown in FIGS. 6 and 4, so the operating speed will be faster.

Next, operate the operating rod 29 to move the second cam member 30.
When moved in the direction away from the first cam member 19,
As shown in FIG. 8, the first cam member 19 is pushed toward the second cam member 30 by the force of the spring 26, and the stopper 27
It engages with the teeth 27a of the cam member 30 and moves toward the second cam member 30 while rotating in the direction of the arrow B shown in the same figure, and when it rotates 90 degrees, the rotation is blocked by the stopper 27, and as shown in FIGS. 1 and 4. The state shown in FIG. 1 is reached, with orifice 15.16 being closed and orifice 17.18 being open. Therefore, if the gas spring 1 is operated in this state, the resistance of the fluid passing through the orifice will be greater than in the states shown in FIGS. 7 and 5, and the operating speed will be slower.

Therefore, one end of the cylinder 2 of the gas spring 1 equipped with a one-way valve is attached to the body of the passenger car, and the end of the piston rod 5 is attached to the hatchback door, and the operating rod 29 is operated according to the season. By switching the selection of the orifice to be opened, the hatchback door can always be opened and closed at a desired opening and closing speed even if the temperature changes depending on the season.

Further, in the above embodiment, an example was described in which the gas spring of this invention is applied to open and close the hatchback door of a passenger car, but the invention is not limited to this, and for example, it can be applied to a pillar of a doorway etc. via a hinge so that it can be opened and closed freely. Alternatively, the tip of the piston rod of the gas spring 1 may be rotatably attached to the attached door, and one end of the cylinder 2 of the gas spring 1 may be rotatably attached to a predetermined location of the frame around the door via a mounting member. good.

In this way, if the gas spring 1 of the present invention is applied to a door that opens via a hinge such as an entrance/exit, even if the ambient temperature changes depending on the season, the operating rod 2 can be adjusted according to the season as described above.
By operating 9 and switching the selection of the orifice to be released, a desired door opening/closing speed can always be obtained. Further, even in the same season, the operation rod 29 can be automatically set so that the operating speed of the gas spring 1 is faster when opening the door and slower when closing the door. For example, even in this case, the door can be opened and closed at a desired speed.

Further, in each of the above embodiments, the first cam member 19,
Four ratchet teeth 23 on each second cam member 30
．． 32, and by operating the operating rod 29 to select one type of orifice with a diameter of two sizes, large or small, the operating speed of the gas spring is switched to two stages; however, the operation speed of the gas spring is not limited to this. The number of orifices with different diameters formed in the piston 4 and the first. By increasing the number of ratchet teeth 23.32 formed on the second cam member 19.30, the operating speed of the gas spring can be switched to two or more stages.

In addition, by appropriately changing the shape of the seven flange portions 21 of the first cam member 19, it is possible to create either a state in which the orifices formed in the piston 4 are opened by the flange portions 21 or a state in which all of these orifices are closed. If you switch all the orifices to the closed state, you can lock the operation of the gas spring, which is very convenient.

〔Effect of the invention〕

By operating the operating rod, the effective cross-sectional area of the multiple orifices formed in the piston can be changed, so the operating speed of the gas spring can be changed.
This allows the operating speed of the gas spring to be changed in response to changes in the temperature of the environment. Therefore, when the gas spring of the present invention is applied to opening and closing a door, it is particularly effective because the opening and closing speed can be changed between when opening and closing the door.

[Brief explanation of the drawing]

1 to 8 show an embodiment of the present invention. FIG. 1 is a vertical sectional view of the main part, FIG. 2 is a partially cutaway vertical sectional view, and FIG. 4 is a sectional view taken along line IV-■ in FIG. 1, and FIG. 5 is a sectional view similar to FIG. 4 when the first cam member is pressed by the second cam member. cross section,
6 to 8 are views showing the positional relationship between the ratchet teeth of the first cam member, the second cam member, and the stopper. DESCRIPTION OF SYMBOLS 1... Gas spring, 2... Cylinder, 4... Piston, 5... Piston rod, 13... Front chamber, 14... ...Rear chamber, 15, 16.17.18... Orifice passage, 19...-First cam member, 23.32...
... Ratchet tooth, 27 ... Stopper, 30
...Second cam member.

Claims (1)

[Claims] In a gas spring in which a piston rod is urged in the axial direction of the cylinder by the pressure of gas sealed in the cylinder, the piston is provided with a plurality of orifice passages having different effective cross-sectional areas and communicating the front and rear chambers of the piston, In order to select a predetermined orifice passage among the plurality of orifice passages, a first cam member having ratchet teeth formed at one end is rotatable about the axial direction of the cylinder and freely movable in the axial direction. a stopper that engages with the ratchet teeth to prevent rotation of the first cam member; further engages with the ratchet teeth to disengage the first cam member from the stopper;
A gas spring characterized in that a second cam member that rotates the first cam member by a predetermined rotation angle is provided movably in the axial direction of the cylinder.