Air damper

Abstract

Air damper which includes: a tubular cylinder (1) in which both end parts are open and in which a shock tube (5) is formed, a piston (2) moving in the cylinder (1), and a cap (3) closing an end opening (1a) of the cylinder (1), wherein the cylinder (1) has an annular sealing surface (4) formed on a peripheral surface of the one end opening (1a), wherein the cap (3) is mounted on the one end opening (1a) of the cylinder (1) such that it can be moved or deformed along an axial direction of the cylinder (1), wherein the cap (3) is brought into contact with the sealing surface (4) in accordance with a pressure change due to a movement of the piston (2) in the cylinder (1) or is separated from it, and wherein a first opening (14) opens in a base plate (12) of the cap (3), characterized in that: a butt part which is smaller than the diameter of the sealing surface (4) but larger than the diameter of the first opening (14) is present between the cap (3) and the cylinder (1), a second opening (17, 21, 22) having a smaller inlet area than the first opening (14) is defined between the cap (3) and the cylinder (1) during operation of the first opening (14) when a base plate surface (12a) recessed by one step and a distal end part of the shock tube (5) are brought into a complete butting relationship with each other, and the abutment part has a recessed space (6) whose diameter is larger than the first opening (14).

Description

Technical area

[0001] The present invention relates to a cylinder type air damper used, for example, for a glove box in a motor vehicle. State of the art

[0002] An air damper according to the preamble of claim 1 is already known from JP 2000 - 170 816 A. Similar air dampers are also described in EP 1 662 170 A1 and in JP 2006 - 283 877 A.

[0003] Although not specifically shown, this type of conventional air damper includes a tubular cylinder open at both ends, a piston moving within the cylinder, and a cap closing one end opening of the cylinder. In the cylinder, an annular sealing surface is formed on an inner peripheral surface of one end opening. The cap includes a disc-shaped base plate mounted in the one end opening of the cylinder so as to be movable along an axial direction of the cylinder, and an annular sealing flange extending from the base plate and protruding in a radial direction, opening an opening in the base plate (see, for example, Patent Document 1).

[0004] When this air damper is used in a glove box of an automobile, the cylinder is rotatably fixed to an instrument panel, and a distal end portion of a piston rod protruding from the other end portion of the cylinder is rotatably fixed to the glove box. Then, when the glove box is moved in an opening direction, the piston rod is gradually withdrawn from the inside of the cylinder, and the piston rod moves in the same direction as the cylinder. At this time, because the base plate of the cap can move due to a pressure change in the cylinder, so that the sealing flange of the cap comes into close contact with the sealing surface of the cylinder in an optimal manner, it can be ensured that the glove box slowly moves to an open state due to the flow resistance of the air passing through one opening.

[0005] Conversely, when the glove box is moved in a closing direction, the piston rod is gradually pushed into the cylinder due to the movement of the glove box, causing the piston to move in the same direction within the cylinder. However, due to a pressure change within the cylinder, the base plate of the cap moves in a reverse direction through the air within the cylinder, causing the sealing flange to move away from the sealing surface of the cylinder and cause the air to escape from the cylinder to the outside. This promotes the closing of the glove box.

[0006] Patent document 1: JP 2000 - 65 116 A Description of the inventionProblem of the invention

[0007] In the conventional air damper, because the inlet area of the opening does not change when the input load changes, a large difference in the opening speed of the glove box may occur, for example, between a situation in which the air damper is used in a glove box with a heavy object loaded therein and a situation in which the air damper is used in a glove box with a light object loaded therein. Problem solution of the invention

[0008] It is an object of the present invention to solve the above-described problem of the conventional air damper.

[0009] This object is achieved by the air damper according to claim 1. Preferred embodiments are claimed in the dependent claims. Advantage of the invention

[0010] According to claim 1, since the first opening is activated at a low input load and the second opening is activated at a high input load to increase the braking force, the air damper can be controlled so that no large difference is generated in the opening speed of the glove box by the weight of a loaded object.

[0011] According to claim 2, the second opening can be simply defined by a groove. If the second opening is defined by a hole, the mold has a needle-like shape. On the other hand, if the second opening is provided in the form of a groove, rib-shaped projections can be simply provided on the mold, so that the diameter of the second opening can be made as small as possible while ensuring the strength of the mold for the second opening.

[0012] According to claim 3, the second opening is defined by the fine concave / convex shapes, so that the strength of the mold can be further increased than when the opening is defined by a hole or a groove.

[0013] According to claim 4, the second opening is defined by the through hole, so that the second opening is hardly subjected to the effect of an abutting attitude of the cap or the cylinder, so that a stable operation of the second opening can be ensured.

[0014] According to claim 1, the air flowing into the recessed space from the first opening moves spirally in the recessed space and flows into the second opening with difficulty, so that the flow resistance and thus the braking force are increased.

[0015] According to claim 5, the through-hole is provided in the lower or side part of the recessed space, so that the through-hole is hardly subjected to the effect of abutting posture of the cap or cylinder, thus ensuring stable operation of the second port. Furthermore, because the second port defined by the second port is easily connected to the first port via the recessed space whose diameter is larger than the first port, the assembly work is simplified. Furthermore, the air flowing into the recessed space from the first port moves spirally and is difficult to flow into the second port, so that the flow resistance and thus the braking force are increased.

[0016] According to claim 6, the groove defining the second opening is formed on the cap, so that a plurality of air dampers having different braking forces can be provided inexpensively for a common cylinder by simply exchanging the caps.

[0017] According to claim 7, the fine concave / convex shapes defining the second opening are formed on the cap, so that a plurality of air dampers having different braking forces can be provided inexpensively for a common cylinder by simply exchanging the caps.

[0018] According to claim 8, the first opening is located on the axis of the cylinder, so that no circumferential alignment of the cap is required when assembling the cap, thus simplifying the assembly work.

[0019] According to claim 9, the cap is formed of a soft material so that the cap can engage the groove or the fine concave / convex shapes and the groove and the fine concave / convex shapes can elastically deform so that the braking force can be changed as needed. Brief description of the drawings Fig. 1 is a partially cutaway front view showing an air damper according to a first embodiment of the invention. Fig. 2 is a main part sectional view of a cylinder. Fig. 3A is a sectional view of a cap; and Fig. 3B is a front view of the cap. Fig. 4 is a main part sectional view showing an assembled state of the air damper. Fig. Figure 5 is a main part sectional view showing a low load state. Fig. 6 is a main part sectional view showing a high load condition. Fig. 7 is a main part sectional view showing a state where air can escape from the air cylinder to the outside. Fig. 8 is a front view of a cap in an air damper according to a second embodiment. Fig. 9 is a main part sectional view showing an air damper according to a third embodiment. Preferred embodiment of the invention

[0020] The invention is based on an air damper comprising: a tubular cylinder open at both ends; a piston moving in the cylinder; and a cap closing one end opening of the cylinder; wherein the cylinder has an annular sealing surface formed on a peripheral surface of one end opening; wherein the cap is mounted on one end opening of the cylinder so as to be capable of moving or deforming along an axial direction of the cylinder to be brought into contact with or released from the sealing surface in accordance with a pressure change due to movement of the piston in the cylinder; wherein a first opening opens in a base plate of the cap; characterized in that a second opening having a smaller inlet area than the first opening is defined between the cap and the cylinder during operation of the first opening.In this configuration, when an input load changes, the first port automatically switches to the second port to provide an appropriate braking force. (First embodiment)

[0021] In the following, the invention is described in detail with reference to various preferred embodiments. As in Fig. 1, an air damper according to a first embodiment comprises a tubular cylinder opening at both end portions, a piston 2 moving in the cylinder 1, and a cap 3 closing one end opening of the cylinder 1.

[0022] As also in Fig. 2, in the cylinder 1, an annular sealing surface 4, which moves into contact with or away from a sealing flange 13 of the cap 3 in response to a pressure change as described below, is formed on an inner peripheral surface of an end opening 1a. In addition, a one-side closed shock tube 5, which projects toward the cap 3 and has an inwardly opening depressed space 6, is formed at a central part of a bottom plate defining the sealing surface 4, while an extension wall 7, which extends outward, is formed contiguously to a peripheral edge of the sealing surface 4. A plurality of locking holes 8 and recessed portions 9 are formed in the extension wall 7. Although not specifically shown, the other end opening of the cylinder 1 is formed in a shape into which a piston rod 10 can be inserted.It should be noted that the sealing surface 4 may also be formed on an outer peripheral surface of one end opening 1a.

[0023] The piston 2 is cast in one piece with the piston rod 10 and is elastically preloaded to one end opening 1a of the cylinder 1 by a preload spring pressure of a compression coil spring 11.

[0024] The cap 3 is cast in one piece from a soft thermoplastic elastomer and comprises, as shown in Fig. 3A and Fig. 3B, a disc-shaped base plate 12 is fixed to the extension wall 7 so as to be movable along an axial direction of the cylinder, and an annular sealing flange 13 extends from the disc-shaped plate 12 and projects radially. A first opening 14 opens in a central part of the base plate 12 to be positioned on an axis of the cylinder 1, while locking parts 15 movably locked in the locking holes 8 and positioning parts 16 locked in the recess parts 9 are formed on a peripheral surface of the disc-shaped base plate 12, so that the sealing flange 13 is moved into contact with or away from the sealing surface 4 of the cylinder 1 by a pressure change associated with the movement of the piston 2 in the cylinder 1.A configuration may also be used in which the cap 3 is fixed to the cylinder 1 in such a way that it cannot be moved, so that the sealing flange 13 is moved into contact with or away from the sealing surface 4 of the cylinder 1 by a pressure change due to the movement of the piston 2 in the cylinder 1.

[0025] Furthermore, as shown in the figure, in the cap 3, a base plate surface 12a facing a distal end portion of the shock tube 5 of the cylinder 1 is recessed by one step. When a large load is applied to the air damper, the base plate surface 12a recessed by one step and the distal end portion of the shock tube 5 abut against each other, thereby forming an abutting portion between the cap 3 and the cylinder 1. Furthermore, a single groove 17 is formed on the base plate surface 12a recessed by one step so as to extend outward in the outer diameter direction of the abutting portion. In the abutting state between the base plate surface 12a recessed by one step and the distal end portion of the shock tube 5, the single groove 7 can be used to define a second port having a smaller inlet area than that of the first port 14.And when no load or only a small load is applied to the air damper, the shock part is provided such that a gap 18 can be formed between the base plate surface 12a recessed by one step and the distal end part of the shock tube 5.

[0026] When the air damper configured as described above is assembled, the compression coil spring 11, the piston rod 10, and the piston 2 are inserted into the cylinder 1 from one end opening 1a, and then the cap 3 is pressed into the extension wall 7, aligning the positioning parts 16 with the recessed parts 9 in the extension wall 7 of the cylinder 1. Then, the locking parts 15 on the cap 3 are movably locked into the locking holes 8 in the extension wall 7, so that the air damper, which is of the one-way type, as shown in Fig. 4 can be easily installed.

[0027] Then, when the air damper is actually used in a glove box of a motor vehicle, the piston rod 10 only needs to be rotatably fixed to the glove box via a mounting hole 20 at a distal end part of the piston rod 10, similar to the conventional air damper when the cylinder 1 is rotatably fixed to the instrument panel via a mounting part 19, which, however, is not specifically shown here.

[0028] Then, when the glove box is moved in an opening direction, the piston rod 10 is gradually pulled out from the inside of the cylinder 1. Although the cap 3 also tries to move to be pulled into the inside of the cylinder 1 while the piston 2 moves in the same direction in which the piston rod 10 is moved from the inside of the cylinder 1, when a small load is applied to the air damper, the moving speed of the piston 2 becomes slow, so that the negative pressure in the cylinder 1 is not drastically increased. Therefore, the moving distance of the cap 3 is as shown in Fig. 5, the sealing flange 13 of the cap 3 is tightly and completely connected to the sealing surface 4 of the cylinder 1 like a suction button, but the gap 18 is secured between the one-step recessed base plate surface 12a of the cap 3 and the distal end portion of the shock tube 5. This ensures that the glove box moves slowly in the opening direction due to the flow resistance of the air flowing only through the first opening 14 in the base plate 12 of the cap 3.

[0029] However, if the load acting on the air damper is high, such as when a heavy object is loaded into the glove box, the negative pressure in the cylinder 1 increases rapidly and the cap 3 moves as in Fig. 6, so that the one-step recessed base plate surface 12a and the distal end portion of the shock tube 5 are brought into complete abutting relationship with each other. At this time, because the second opening, whose inlet area is smaller than that of the first opening 14, is defined by the groove 17, the opening is automatically switched from the first opening to the second opening, so that the opening speed of the glove box can be controlled in accordance with the air resistance of the air passing through the second opening. In addition, the shock tube 5 functions as a stopper during such automatic switching, whereby the cap 3 can be effectively prevented from falling into the interior of the cylinder 1.

[0030] Furthermore, the air flowing in from the first opening 14 is introduced into the recessed space 6, the diameter of which is larger than the first opening 14 of the shock tube 5 of the cylinder 1, and moves in a spiral manner. Thus, the air thus introduced has difficulty flowing into the second opening, increasing the flow resistance and thus the braking force. The groove 17 formed in the cap 3 allows a variety of air dampers with different braking forces to be inexpensively provided for use in a common cylinder 1 by simply exchanging the caps 3. Furthermore, because the first opening 14 is positioned on the axis of the cylinder 1, no circumferential alignment of the cap 3 is required during assembly, thereby advantageously simplifying the assembly work.And when the groove 17 is formed in the abutment part of the cylinder 1, the cap 3 formed of the soft thermoplastic elastomer engages in the recess, whereby the braking force can be changed according to the requirements.

[0031] In the first embodiment, when the second opening is defined by a hole rather than the groove 17, the mold for forming the hole is needle-shaped. If the needle-shaped mold is too thin, the mold is prone to breakage. On the other hand, when the second opening is defined by the groove 17, only rib-like projections need to be provided on the mold. This not only allows the groove 17 to be easily molded, but also allows the diameter of the second opening to be kept as small as possible while simultaneously ensuring the strength of the mold.

[0032] On the other hand, when the glove box is moved in a closing direction, the piston rod 10 is gradually pushed into the cylinder in response to the movement of the glove box. Although the piston 2 moves in the same direction in the cylinder 1, this time, as in Fig. As shown in Figure 7, the sealing flange 13 of the cap 3 is moved away from the sealing surface 4 of the cylinder 1 by the air accumulated in the cylinder 1 due to a pressure change in the cylinder 1, so that the air accumulated in the cylinder 1 is expelled to the outside. Therefore, the piston 2 can return to its original position without resistance, thereby promoting the closing of the glove compartment.

[0033] In the first embodiment, the second opening consists of a combination of the groove 17 and the recessed space 6, but the second opening can also be formed without the recessed space 6. In this case, the groove 17 must be directly connected to the first opening 14 and therefore extend to an outer diameter side of the abutting part. Therefore, the groove 17 is preferably formed on the cap 3 rather than on the cylinder 1, because in this case, the assembly accuracy does not need to be controlled. (Second embodiment)

[0034] An air damper according to a second embodiment will be described below. The air damper according to the second embodiment corresponds to that of the first embodiment in terms of its basic features and is based on the configuration of the first embodiment. The air damper of the second embodiment differs from that of the first embodiment in the Fig. 8, in which fine concave / convex shapes 21 are continuously formed over the entire one-step recessed base plate surface 12a of the cap 3, so that in a state where the one-step recessed base plate surface 12a of the cap 3 abuts against a distal end portion of a shock tube 5, a second opening can be defined by the fine concave / convex shapes 21 instead of the groove 17 of the first embodiment. Of course, the inlet area of the second opening defined by the fine concave / convex shapes 21 is smaller than that of the first opening 14.

[0035] In the second embodiment, when a small load is applied to the air damper, the moving distance of the cap 3 also becomes small, and in a state where a gap 18 between the one-step recessed base plate surface 12a of the cap 3 and a distal end part of the shock tube 5 is sufficiently secured, the sealing flange 13 of the cap is closely and completely connected to a sealing surface 4 of the cylinder 1, thereby ensuring a slow movement of the glove box in an opening direction.

[0036] When the load acting on the air damper is high, such as when a heavy object is loaded into the glove box, the cap 3 moves widely within the cylinder 1, bringing the one-step recessed base plate surface 12a into full abutment with the distal end portion of the shock tube 5, and the second opening, whose inlet area is smaller than that of the first opening 14, is defined by the fine concave / convex shapes 21. Then, the first opening is automatically switched to the second opening, so that the opening speed of the glove box can be controlled as required by the flow resistance of the air passing through the second opening.

[0037] Also in the second embodiment, similar to the first embodiment, the air flowing in from the first port 14 is introduced into the recessed space 6 of the shock tube 5 of the cylinder 1, so that it moves spirally and flows into the second port with difficulty, thereby increasing the flow resistance and improving the braking force. Furthermore, because the fine concave / convex shapes 21 are formed on the cap 3, a plurality of air dampers with different braking forces can be provided for a common cylinder 1 at low cost by simply replacing the caps 3. On the other hand, when the fine concave / convex shapes 21 are formed on the shock part of the cylinder 1, the soft cap 3 formed of a soft thermoplastic elastomer can engage with the fine concave / convex shapes 21, so that the braking force can be changed as needed.

[0038] In the second embodiment, a configuration is used in which the second opening is defined by the fine concave / convex shapes 21, wherein the fine concave / convex shapes 21 used as the second opening can be molded more easily than a hole or a groove 17, and the diameter of the second opening can be made as small as possible while ensuring the strength of the mold. (Third embodiment)

[0039] An air damper according to a third embodiment will be described below. In the air dampers of the first and second embodiments, the second opening is formed on the cap 3. In the third embodiment, as in Fig.As shown in Fig. 9, a through-hole 22 connected to the interior of a cylinder 1 is formed at a lower or side portion of a shock tube 5, so that a second opening can be defined by this through-hole 22 instead of the groove 17 in the first embodiment or the fine concave / convex shapes 21 in the second embodiment when the one-step recessed base plate surface 12a of the cap 3 and the distal end portion of the shock tube 5 are brought into abutting relationship. Of course, the inlet area of the second opening defined by the through-hole 22 is smaller than that of the first opening 14.

[0040] And in the third embodiment, when a small load is applied to the air damper, the moving distance of the cap 3 becomes small, so that in a state where a gap 18 is secured between the one-step recessed base plate surface 12a and the distal end part of the shock tube 5, the sealing flange 13 of the cap is closely and completely connected to the sealing surface 4 of the cylinder 1, thereby ensuring that the glove box moves slowly in the opening direction.

[0041] When the load acting on the air damper is high, such as when a heavy object is loaded into the glove box, the cap 3 moves widely within the cylinder 1, thereby bringing the one-step recessed base plate surface 12a into full abutment with the distal end portion of the shock tube 5, with the inlet area of the second opening defined by the through-hole 22 being smaller than that of the first opening 14. Then, the first opening is automatically switched to the second opening, so that the opening speed of the glove box can be controlled as required by the flow resistance of the air passing through the second opening.

[0042] Also in the third embodiment, similarly to the first embodiment, the air flowing in from the first port 14 is introduced into a recessed space 6 of the shock tube 5 of the cylinder 1 and moves spirally, so that the air hardly flows into the second port, thereby increasing the flow resistance and improving the braking force. Furthermore, in the third embodiment, because the through-hole 22 is formed not on the cap 3 but on a lower or side part of the shock tube 5, the second port is hardly subjected to the effects of the attitudes of the cap 3 and the cylinder 1 abutting against each other, thus ensuring stable operation. Industrial applicability

[0043] Because the air damper according to the invention can change the braking force in accordance with a change in the input load to provide an appropriate braking force corresponding to a high input load of the air damper, a satisfactory result is obtained when the air damper is applied to a glove box in a motor vehicle or the like. Explanation of reference symbols 1 cylinder 1a an end opening 2 pistons 3 caps 4 Sealing surface 5 Shock tube 6 recessed space 7 Extension wall 8 locking hole 9 Excerpt 10 Piston rod 11 Compression coil spring 12 Base plate 12a Base plate surface recessed by one step 13 Sealing flange 14 first opening 15 Locking part 16 Positioning part 17 grooves 18 gap 19 Assembly part 20 mounting holes 21 fine concave / convex shape 22 through hole 23 Outer diameter of the joint part

Claims

[1] Air damper, which includes: a tubular cylinder (1) in which both end parts are open and in which a shock tube (5) is formed, a piston (2) moving in the cylinder (1), and a cap (3) closing an end opening (1a) of the cylinder (1), wherein the cylinder (1) has an annular sealing surface (4) formed on a peripheral surface of the one end opening (1a), wherein the cap (3) is mounted on the one end opening (1a) of the cylinder (1) such that it can be moved or deformed along an axial direction of the cylinder (1), wherein the cap (3) is brought into contact with the sealing surface (4) in accordance with a pressure change due to a movement of the piston (2) in the cylinder (1) or is separated from it, and wherein a first opening (14) opens in a base plate (12) of the cap (3), characterized by , that: a butt part which is smaller than the diameter of the sealing surface (4) but larger than the diameter of the first opening (14) is present between the cap (3) and the cylinder (1), a second opening (17, 21, 22) having a smaller inlet area than the first opening (14) is defined between the cap (3) and the cylinder (1) during operation of the first opening (14) when a base plate surface (12a) recessed by one step and a distal end part of the shock tube (5) are brought into a complete butting relationship with each other, and the abutment part has a recessed space (6) whose diameter is larger than the first opening (14). [2] Air damper according to claim 1, characterized by , that: a groove (17) is formed on an abutting surface of the abutting part and extends in an outer diameter direction of the abutting part, and the second opening (17) is defined by the groove (17). [3] Air damper according to claim 1, characterized by , that: fine concave / convex shapes (21) are formed on an abutting surface of the abutting part, and the second opening (21) is defined by the fine concave / convex shapes (21). [4] Air damper according to claim 1, characterized by , that: a through hole (22) connected to the interior of the cylinder (1) is formed in the impact part, and the second opening (22) is defined by the through hole (22). [5] Air damper according to claim 4, characterized by , that: the through hole (22) is formed in a lower or lateral part of the recessed space (6). [6] Air damper according to claim 2, characterized by , that: the groove (17) is formed on the cap (3). [7] Air damper according to claim 3, characterized by , that: the fine concave / convex shapes (21) are formed on the cap (3). [8] Air damper according to one of claims 1 to 7, characterized by , that: the first opening (14) is positioned on an axis of the cylinder (1). [9] Air damper according to one of claims 2 or 3, characterized by , that: the cap (3) is made of a soft material.

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