JP4839175B2 - Air suspension - Google Patents

Description

  The present invention relates to an air suspension, and more particularly to an improvement of an air suspension suitable for use as a shock absorber that is mounted on a front wheel side of a bicycle and absorbs road surface vibrations input to the front wheel.

  There have been various proposals for shock absorbers that are mounted on the front wheel side of the bicycle and absorb road vibrations input to the front wheels. Among them, for example, Patent Document 1 discloses a reaction force made of metal. There is a proposal that it is obtained not by expansion / contraction of the coil spring but by expansion / contraction of air.

  That is, in Patent Document 1, a rod body that is a lower end side member is slidably inserted into a cylinder body that is an upper end side member, and a piston is slidably housed in the cylinder body, and the piston is inserted into the cylinder body. A suspension as a shock absorber is disclosed in which a rod side chamber defined by a piston in the cylinder body is a gas chamber filled with air.

  Therefore, in the suspension disclosed in Patent Document 1, since the rod side chamber defined by the piston in the cylinder body is a gas chamber filled with air, the reaction force is generated when the gas chamber is expanded and contracted. The air spring force is exerted, and since the air chamber portion defined in the piston chamber in the cylinder body is provided, the air spring force that is also a reaction force is exhibited by the expansion and contraction of the air chamber portion.

As a result, in the suspension disclosed in Patent Document 1, the reaction force at the time of extension can be obtained by contraction of air, and the reaction force at the time of contraction can also be obtained by contraction of air instead of a metal coil spring. As a result, the overall weight of the suspension can be reduced, and when this suspension is used as a shock absorber on the front wheel side of the bicycle, the mass on the front wheel side of the bicycle is reduced to improve the handleability of the steering wheel. Will get.
Special table 2001-501155 (see page 12, line 16 to line 26, page 19, line 16 to page 28, line 1, see FIGS. 1 to 5)

  However, the suspension disclosed in the above-mentioned Patent Document 1 has a slight disadvantage because it can reduce the overall weight and is a cylindrical shock absorber. May be pointed out.

  That is, as is the case with conventional well-known shock absorbers, even in the above-described suspension, the reaction force during contraction is the reaction force in the piston side chamber in the cylinder body, but the so-called vehicle body that contracts the suspension. Since it is against the load, it is usually very large compared to the reaction force when the suspension is extended.

  As a result, the above-described suspension has a structure capable of resisting the internal pressure that is a reference for the reaction force in the piston side chamber, and the seal member has high durability that can resist the internal pressure that is the reference for the reaction force in the piston side chamber. There is a problem that it is required to have the property.

  The present invention was created in view of such a current situation, and the object of the present invention is to greatly reduce the durability of the seal member as well as to reduce the overall weight. It is possible to provide an air suspension that is optimal for expecting an improvement in its versatility.

In order to achieve the above object, the means of the present invention includes an outer tube connected to the handle side of a bicycle, a wheel side inner tube inserted in and out of the outer tube, and a slide in the inner tube. A rod housed in the inner tube, and a rod body inserted into the inner tube and connected to the piston, and a rod side chamber defined by the piston in the inner tube And an air suspension for a bicycle having a piston side chamber, a gas chamber defined by the insertion of the inner tube is provided in the outer tube, the rod side chamber is configured as a gas chamber, and the piston side chamber is always in communication with the atmosphere. is, the gas chamber in the outer tube of the inner tube It is characterized in that it has a diameter standard diameter of the internal pressure.
In this case, the cross-sectional area of the gas chamber defined in the outer tube is a value obtained by subtracting the cross-sectional area of the rod body from the cross-sectional area derived from the outer diameter of the inner tube, while the cross-sectional area of the rod body is It is preferable to set it smaller than the cross-sectional area of the inner tube.
Similarly, the rod body has a passage that allows communication between the gas chamber, which is a rod side chamber defined by a piston in the inner tube, and the outside, and a check valve that allows supply of air from the outside is provided in this passage. It is preferable to be made.
Similarly, it is preferable that the outer tube has a passage that allows communication between the gas chamber in the outer tube and the outside, and a check valve that allows supply of air from the outside is provided in this passage.

According to the air suspension for a bicycle of the present invention, a gas chamber is defined in the outer tube, a rod side chamber in the inner tube is also defined as a gas chamber, and the piston side chamber in the inner tube is always in communication with the atmosphere. When the gas tube extends, the gas chamber in the inner tube contracts to generate an air reaction force. At the time of contraction, the gas chamber in the outer tube contracts to generate an air reaction force.

Accordingly, since the cross-sectional area in the gas chamber in the outer tube is larger than the cross-sectional area in the piston-side chamber, the cross-sectional area in the outer tube is larger than the internal pressure based on the cross-sectional area in the piston-side chamber when the load from the vehicle body is the same. The internal pressure based on is lower.

As a result, compared to the setting that depends on the piston diameter for the internal pressure during contraction, the setting that depends on the outer diameter of the inner tube can provide a so-called margin for the mechanical structure and the seal member, Durability can be improved, which contributes to reduction of the overall weight.

  The present invention will be described below on the basis of the illustrated embodiment. The air suspension according to the present invention is, as illustrated, a buffer that is mounted on the front wheel side of a bicycle and absorbs road surface vibrations input to the front wheel. It is supposed to be embodied as a container.

  Therefore, this shock absorber will be described. First, in principle, as shown in FIG. 1, the shock absorber has an outer tube 1, an inner tube 2, a piston 3, and a rod body 4.

  The outer tube 1 is an upper end side member in the shock absorber. Specifically, the upper end side is connected to the handle side (not shown) of the bicycle, and the upper end side of the inner tube 2 can be projected and retracted at the lower end side. It is going to be inserted.

  The inner tube 2 is a lower end side member in the shock absorber. Specifically, the lower end side is connected to a wheel side (not shown) in the bicycle, and the upper end side is inserted into the outer tube 1 so as to be able to appear and retract. Thus, the gas chamber A as a room is defined in the outer tube 1.

  The piston 3 is slidably accommodated in the inner tube 2, and in the inner tube 2, a gas chamber B that is a rod side chamber that is an upper side of the piston 3 in the drawing and a lower side of the piston 3 in the drawing. The piston side chamber C communicating with the counter is defined.

  The rod body 4 is suspended from the shaft core portion of the outer tube 1 in a state where the upper end is connected to the shaft core portion of the upper end portion of the outer tube 1, and the lower end side is inserted into the inner tube 2 so as to be able to protrude and retract. The piston 3 is connected to the tip which is the lower end in the figure introduced into the inner tube 2.

  Therefore, in the shock absorber formed as described above, the gas chamber A is defined in the outer tube 1, the gas chamber B is defined in the inner tube 2, and also the inner tube 2. Since the piston-side chamber C defined inside is communicated with the atmosphere, it can contribute to the reduction of the overall weight.

  In this shock absorber, the gas chamber B in the inner tube 2 contracts during expansion to generate an air reaction force, and during the contraction, the gas chamber A in the outer tube 1 contracts to cause air reaction. Will generate power.

  The above is the basic configuration of the shock absorber. First, in the shock absorber, the outer tube 1 has the check valve 1b at the upper end 1a. The check valve 1b Therefore, it is assumed that supplementary supply of air from the outside to the gas chamber A in the outer tube 1 is permitted.

  Next, in this shock absorber, the rod body 4 has a passage 4a that allows communication between the gas chamber B and the outside, and a check valve 4b in the passage 4a. It is assumed that supplementary supply of air from the outside to the gas chamber B is permitted by 4b.

  By the way, in the above-described shock absorber, the gas chamber A in the outer tube 1 is, in principle, formed by setting the outer diameter of the inner tube 2 to the reference diameter of the inner pressure. 1 is obtained by subtracting the cross-sectional area of the rod body 4 from the cross-sectional area derived from the outer diameter of the inner tube 2, so that the internal pressure in the gas chamber A is obtained. Is supposed to be set.

  Therefore, in this shock absorber, when the inner tube 2 is immersed in the outer tube 1, an internal pressure based on the annular cross-sectional area a is generated.

  In other words, the shock absorber of this kind contracts when a so-called vehicle body load is applied, and the load at this time is so large that it cannot be compared with the load when the shock absorber extends. This is the rule of thumb.

  Incidentally, the internal pressure of the gas chamber B at the time of expansion of the shock absorber shown in the figure is a reference value obtained by subtracting the cross-sectional area of the rod body 4 from the cross-sectional area of the piston 3 in the annular cross-sectional area indicated by b in FIG. Is set.

  On the other hand, in this shock absorber, assuming that the piston side chamber C defined by the accommodation of the piston 4 in the inner tube 2 is a closed gas chamber, the piston side chamber when the shock absorber contracts. The internal pressure of C is set to the reference value of the cross-sectional area of the piston 3, that is, the cross-sectional area having a circular shape indicated by the symbol c in FIG.

  On the other hand, in the present invention, the internal pressure generated when the shock absorber contracts is assumed to be the internal pressure in the gas chamber A in the outer tube 1, and at this time, the annular break indicated by the symbol a in the drawing is used. The area becomes the reference area as described above.

  Therefore, in this shock absorber, as long as the cross-sectional area of the rod body 4 is set so as not to exceed the cross-sectional area of the inner tube 2, the cross-sectional area c of the piston-side chamber C in the gas chamber A in the outer tube. Since the cross-sectional area a becomes larger, it can be said that the internal pressure based on the cross-sectional area a is lower than the internal pressure based on the cross-sectional area c when the load from the vehicle body acting on the shock absorber is the same.

  As a result, in this shock absorber, the inner pressure at the time of contraction is compared with a setting that depends on the diameter of the piston 3, and compared with the case where the same mechanical structure and seal member are employed, the outer pressure of the inner tube 2 is increased. It can be said that the setting depending on the diameter makes it possible to give a so-called margin to the mechanical structure and the seal member, and to improve the durability.

  FIG. 2 to FIG. 4 show an example in the case where the above-described shock absorber is specifically formed. Hereinafter, this will be described a little, but first, as shown in FIG. An inner tube 2 as a lower end side member is inserted in the outer tube 1 as an upper end side member so as to be able to protrude and retract. At this time, a bearing member 21 is interposed on the outer periphery of the upper end portion 2c of the inner tube 2. Thus, the outer periphery of the bearing member is brought into sliding contact with the inner periphery of the outer tube 1.

  In this shock absorber, a head cap member 22 is screwed to the inner periphery of the upper end portion 2 c of the inner tube 2, and the upper end opening of the inner tube 2 is closed by the head cap member 22.

  Further, the head cap member 22 has the rod body 4 penetrated through the shaft core portion. At this time, the head cap member 22 has a bush member 23 and a seal member 24 that are in sliding contact with the outer periphery of the rod body 4 at the shaft core portion. It is said.

  On the other hand, the piston 3 housed in the inner tube 2 has a piston ring 31 and a piston seal 32 on the outer periphery, and the outer periphery of the piston ring 31 and the piston seal 32 is the inner periphery of the inner tube 2. It is supposed to be in sliding contact.

  The piston 3 is connected to the tip end of the rod body 4 by being screwed to the tip thread portion 4c which is the lower end portion of the rod body 4 in the figure. At this time, the passage 4a is formed. The lower end opening of the through-hole 4d is closed at the shaft core portion of the rod body 4 to be closed.

  The rod body 4 has a communication hole 4e that allows communication between the through hole 4d in the shaft core portion that is the passage 4a and the gas chamber B that is the rod side chamber in the inner tube 2, and the check valve 4b is interposed therebetween. It is supposed that supplementary supply of air from the outside to the gas chamber B is made possible.

  On the other hand, as shown in FIG. 3, an upper end cap member 11 is screwed to the inner periphery of the upper end portion 1 c of the outer tube 1, and the upper end opening of the outer tube 1 is closed by the upper end cap member 11. .

  The upper end cap member 11 has the upper end portion 4f of the rod body 4 screwed to the shaft core portion. At this time, a loosening prevention nut 41 is screwed to the upper end portion 4f of the rod body 4. At the same time, the bump cushion 42 is interposed under the use of the holder 43 in the lower part near the upper end 4f.

  The upper end cap member 11 has rubber bodies 12 and 13 that constitute the check valves 1b and 4b (see FIG. 1), and communication holes 11a and 11b that constitute the passages 1a and 4a (see FIG. 1). It is said to have.

  Therefore, in the check valve including the rubber bodies 12 and 13 and the communication holes 11a and 11b, an injection jig having a so-called injection needle structure is used, that is, through the communication holes 11a and 11b. The rubber bodies 12 and 13 are penetrated by the tool, and air from the outside, for example, air from the air can be supplied to the gas chamber A.

  In the outer tube 1 having the above-described check valve, that is, the upper end cap member 11 having the communication holes 11a and 11b, for example, a dust cap 14 is fitted as shown in a virtual diagram in the figure. It would be nice to be done.

  Further, as shown in FIG. 4, the inner tube 2 has a bottom member 25 screwed to the lower end portion 2c, and the communication hole 2b (see FIG. 1) described above is formed in the shaft core portion of the bottom member 25. The communication hole 25a is provided.

  Incidentally, although not shown, the bottom member 25 is often provided with various brackets for pivotally mounting the shock absorber on the front wheel of the bicycle.

  In the above description, the air suspension of the present invention has been described as being suitable for use as a shock absorber mounted on the front wheel side of a bicycle. However, from the point of view of the present invention, the basic concept of this air suspension is automatic. Of course, it may be embodied in a front fork that is a shock absorber mounted on the front wheel side of the two-wheeled vehicle, and in that case, the effect of the present invention can be exhibited.

It is a longitudinal cross-sectional view which shows the air suspension by this invention in principle. It is a partial front longitudinal cross-sectional view which cuts and shows the principal part of the air suspension by one Embodiment of this invention. It is a figure which shows the upper end part of the air suspension of FIG. 2 similarly to FIG. It is a figure which shows the lower end part of the air suspension of FIG. 2 similarly to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer tube 1a, 4a Passage | path 2b, 4b Check valve 2 Inner tube 3 Piston 4 Rod body 6 Rubber body which comprises a check valve A Gas chamber in an outer tube B Gas chamber which is a rod side chamber C Piston side chamber a The disconnection of the gas chamber A area

Claims (4)

An outer tube connected to the handle side of a bicycle, a wheel-side inner tube inserted in and out of the outer tube, a piston slidably disposed in the inner tube, and a shaft core portion of the outer tube A bicycle air suspension comprising: a rod body that is suspended in the inner tube and connected to the piston; and a rod side chamber and a piston side chamber defined by the piston in the inner tube. A gas chamber defined by the insertion of the inner tube is provided in the outer tube, the rod side chamber is configured as a gas chamber and the piston side chamber is always in communication with the atmosphere, and the gas chamber in the outer tube is connected to the inner tube. self characterized in that the outer diameter of the standard diameter of the internal pressure of the Air suspension for the car. The cross-sectional area of the gas chamber defined in the outer tube is a value obtained by subtracting the cross-sectional area of the rod body from the cross-sectional area derived from the outer diameter of the inner tube. The bicycle air suspension according to claim 1 , wherein the suspension is set smaller than a cross-sectional area. The rod body has a passage that allows communication between the gas chamber, which is a rod side chamber defined by a piston, in the inner tube and the outside, and a check valve that allows supply of air from the outside is provided in this passage. The bicycle air suspension according to claim 1 or 2 . And having a passage the outer tube to permit communication between the gas chamber and the outside of the outer tube, to claim 1, 2 or 3 a check valve that allows the air supply from outside to the passage is disposed Bicycle air suspension as described .

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