JP4526862B2 - Hydraulic shock absorber - Google Patents

Description

  The present invention relates to a hydraulic shock absorber, and more particularly to an improvement of a hydraulic shock absorber that is mounted on a front wheel side of a two-wheeled vehicle and serves as a front fork that absorbs road surface vibration.

  There have been various proposals for a hydraulic shock absorber that is mounted on the front wheel side of a two-wheeled vehicle and serves as a front fork that absorbs road vibration. For example, Patent Document 1 discloses an internal pressure in a built-in damper portion. There has been disclosed a proposal to stabilize the damping action in the damper portion while maintaining a constant state.

  That is, according to the proposal disclosed in Patent Document 1, the hydraulic shock absorber has an inverted damper portion through which a rod body, which is a lower member, is inserted into a cylinder body, which is an upper member, so as to be able to protrude and retract. Built in the part.

  The damper portion includes an internal pressure securing means for maintaining the cylinder body in a constant pressure state in an upper end portion which is a bottom end portion of the cylinder body. The internal pressure securing means is a cylinder body in the vertical direction. It has a free piston-like partition member that slides in the axial direction.

  At this time, the piston portion held by the rod body is slidably accommodated in the cylinder body, and a predetermined damping action at the time of so-called extension side operation is realized by a damping valve disposed in the piston portion. It is supposed to.

  The cylinder body also has a base valve portion on the pressure-receiving surface side of the above-mentioned partition wall member, and a predetermined damping action at the time of so-called pressure-side operation is realized by a damping valve arranged in the base valve portion. It is going to be done.

  By the way, the partition member is provided in a so-called liquid-tight state on the outer periphery of the shaft that is suspended from the shaft core portion of the sealing member that closes the upper end of the cylinder body and holds the base valve portion at the lower end portion. The outer periphery is slidably contacted with the inner periphery of the bottom end of the cylinder body in a liquid-tight state.

  The partition member is urged in the downward direction, which is the forward direction by the pressurizing means arranged on the rear side, that is, the spring force of the coil spring, and resists the spring force of the coil spring by the pressure in the cylinder body. Then you can go backwards, that is, rise.

  Further, the partition member prevents the pressure in the cylinder body from coming out to the so-called rear side at the time of lowering and in the vicinity thereof, while the inner periphery is formed on the outer periphery of the shaft at the highest rise. By aiming at the groove, the pressure in the cylinder body is allowed to escape to the rear side.

Therefore, in the hydraulic shock absorber disclosed in Patent Document 1, the pressure in the cylinder body in the damper portion built in the shaft core portion is maintained constant during the expansion and contraction operation. It is possible to realize an appropriate damping action in the vehicle, and for example, it is possible to maintain a good riding comfort in a two-wheeled vehicle mounted on the front wheel side using the hydraulic shock absorber as a front fork.
JP-A-6-147248 (Claims Claims 1, Paragraphs 0005, 0015, 0016, FIG. 2)

  However, in the hydraulic shock absorber disclosed in Patent Document 1 described above, there is a possibility that it is difficult to require a degree of freedom for the damping action in the built-in damper portion.

  In other words, in the damper portion built in the hydraulic shock absorber, the base valve portion is held by the lower end portion of the shaft that is suspended from the upper end that is the bottom end of the cylinder body. In this case, a partition member constituting the internal pressure securing means is interposed.

  Therefore, even if the base valve portion is extracted from the cylinder body by so-called disassembling work, the partition member is also extracted from the cylinder body, and the work is not easy, and there is a concern that the work may be troublesome.

  In addition, in the above proposal, since the base valve portion is arranged in the cylinder body which is the pressure receiving surface side of the partition member, the damping action in the base valve portion is stored in the cylinder body. It depends on the characteristics of the oil.

  Based on this, even when trying to realize tuning based on the rider's preference with the base valve part, tuning dependent on the characteristics of the oil cannot be realized, and therefore the so-called width that can be tuned is narrowed, and accordingly in tuning It will be pointed out that the degree of freedom is low.

  The present invention was devised in view of such a current situation, and the object of the present invention is a built-in damper portion, which can require a degree of freedom in a damping action, and is a two-wheeled vehicle. It is intended to provide a hydraulic shock absorber that is optimally expected to be improved in versatility as a front fork that is mounted on the front wheel side and absorbs road surface vibration.

In order to achieve the above object, the means of the present invention includes an outer tube, an inner tube slidably fitted to the outer tube, a cylinder body suspended from the upper end of the inner tube, and the outer tube. A rod body that stands up from the lower end and is slidably inserted into the cylinder body via a piston section, a base valve section provided in the cylinder body, and a base valve section that faces the base valve section in the bottom end of the cylinder body. The bottomed cylindrical partition member inserted in a slidable manner, the expansion side chamber and the compression side chamber separated by the piston portion in the cylinder body, and the partition member disposed on the opposite side of the compression side chamber. In the hydraulic shock absorber provided with a coil spring biased in the direction of the pressure side chamber, the cylinder body is opened and closed by the partition member, and the pressure side chamber and the cylinder body outside The forming a communication or blocked causing the communication hole, it is an auxiliary damping portion provided on the end portion of the shaft that is vertically provided from the upper end of the inner tube that is characterized in that inserted into the partition member.
In this case, an accumulator composed of oil and an air chamber above the oil surface of the oil is separated from the back side of the cylinder body facing the compression side chamber by the partition member, and the air chamber contracts when the air chamber contracts. It is preferable that the partition member be subjected to the action of the spring force of the coil spring and the air spring force of the air chamber.
Similarly, the auxiliary damping part is opened and closed in each port, a valve body inserted into the partition member, two ports formed in the valve body and communicating with the accumulator and the oil chamber in the partition member. It is preferable that it is configured by a freely provided damping valve and an extension side check valve.

  Therefore, according to the first aspect of the present invention, since the auxiliary damping portion is disposed inside the partition wall member, when the auxiliary damping portion is extracted from the cylinder body in the so-called disassembling operation, the partition wall member and the cylinder body are also removed. There is no need to remove it from the unit, which makes the work easier.

  Since the auxiliary damping part is disposed in the inner oil of the partition wall member, it can be insulated from the oil stored in the cylinder body, and therefore the damping action in the auxiliary damping part depends on the characteristics of the oil stored inside. It becomes possible to make it.

  In addition, since the base valve portion is disposed on the pressure receiving surface side of the partition wall member, a stable damping action is expected by this base valve portion regardless of whether or not the auxiliary attenuation portion is disposed in the partition wall member. It will be possible.

  In addition, since the base valve portion and the auxiliary damping portion are merged, more effective damping characteristics can be expected.

An embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the hydraulic shock absorber according to the present invention includes an outer tube 1, an inner tube 2 that is slidably fitted to the outer tube 1, and a cylinder body 3 that is suspended from the upper end of the inner tube 2. A rod body 4 erected from the lower end of the outer tube 1 and slidably inserted into the cylinder body 3 via a piston portion 6, a base valve portion 7 provided in the cylinder body 3, and the cylinder A bottomed cylindrical partition member 8 which is slidably inserted into the bottom end portion 3) of the body 3 while facing the base valve portion 7, and is separated by the piston portion 6 in the cylinder body 3. An extension side chamber R1, a pressure side chamber R2, and a coil spring 9 disposed on the opposite side of the pressure side chamber R2 to urge the partition member 8 toward the pressure side chamber R2.
Furthermore, as shown in FIG. 2, in the cylinder body 3 are opened and closed by the partition member 8 to form a communication hole 3c which communicates or blocks the said compression side chamber R2 and the cylinder body 3 outside of the inner tube 2 The auxiliary damping portion 5 provided at the end portion of the shaft 5c suspended from the upper end is inserted into the partition wall member 8.
Further, an accumulator Q consisting of oil and an air chamber A above the oil level O of the oil is separated in the cylinder body 3 by the partition member 8 on the back side facing the pressure side chamber R2. When the chamber A contracts, the partition member 8 receives the action of the spring force of the coil spring 9 and the air spring force of the air chamber A.
The auxiliary damping part 5 includes a valve body 10 inserted into the partition member 8 , two ports formed in the valve body 10 for communicating the accumulator Q and the oil chamber 12 in the separating member 8, Each of the ports is composed of a damping valve 5a and an extension side check valve 5b provided to be freely opened and closed.
This will be described in more detail below.

  As a result, there is a built-in damper part that has a degree of freedom in adjusting the damping action while ensuring a predetermined damping action, and is mounted on the front wheel side of the motorcycle to absorb road surface vibration. Ideal for use as a fork.

  Hereinafter, the present invention will be described based on the illustrated embodiment. The hydraulic shock absorber according to the present invention ensures the reaction force by the internal pressure ensuring means, that is, ensures the internal pressure in the built-in damper portion. For example, it is said that tuning according to the rider's preference is possible.

  Incidentally, although not shown, this hydraulic shock absorber is a front fork that is mounted on the front wheel side of a two-wheeled vehicle and absorbs road surface vibration. In the illustrated embodiment, as shown in FIG. The inner tube 2 as a vehicle body side member is inserted into the outer tube 1 as an upright type telescopic cylinder, and the damper portion is built in the shaft core portion.

  At this time, in the present invention, the damper portion is set to be an inverted type in which the rod body 4 that is the lower member is inserted into the cylinder body 3 that is the upper member so as to be able to protrude and retract. In the hydraulic shock absorber according to the present invention, the auxiliary damping portion 5 is provided in the bottom end portion 3a which is the upper end portion in FIG.

  And in this damper part, while the cylinder body 3 was suspended by the axial center part of the inner tube 2, the rod body 4 stood at the axial center part of the outer tube 1, and was distribute | arranged among both The suspension spring is biased in the extending direction.

  Incidentally, from the point of view of the present invention, as long as the damper portion is set in an inverted type, the above-described telescopic cylinder is replaced with an upright type in which the outer tube 1 is a wheel side tube, Although not shown, it is needless to say that an inverted type in which the outer tube 1 is a vehicle body side tube may be used.

  On the other hand, in the damper portion, in the cylinder body 3, a piston portion 6 held at the tip which is the upper end of the rod body 4 in FIG. 1 is defined as a compression side chamber R2 which is the upper side of the piston portion 6 in FIG. 1 as well as an extension side chamber R1 which is the lower side of the piston portion 6 in FIG. 1, and an extension side damping valve (not shown). The communication between the extension side chamber R1 and the compression side chamber R2 is allowed.

  Further, in the damper portion according to the present invention, as shown in FIG. 2, it is assumed that a base valve portion 7 is disposed inside the end portion of the cylinder body 3 on the bottom end portion 3a side. It is assumed that a predetermined pressure-side damping force is generated by the pressure-side damping valve 7b arranged in parallel with the pressure-side check valve 7a disposed in the portion 7.

  Therefore, in the above-described damper portion, a predetermined extension side damping force is generated by the extension side damping valve disposed in the piston portion 6 when the rod body 4 extends and retracts with respect to the cylinder body 3. At the same time, a predetermined compression side damping force is generated by the compression side damping valve 7 b disposed in the base valve portion 7.

  By the way, as shown in FIG. 2, the internal pressure guarantee means has a partition member 8 that is slidably received in the bottom end portion 3a of the cylinder body 3, and this partition member 8 is a cylinder. The bottom end portion 3a of the body 3 is defined as a pressure receiving surface side that is the piston portion 6 side in the cylinder body 3, that is, the above-described base valve portion 7 side and a rear side that is the opposite side.

  At this time, seal members 8a and 8b that are in sliding contact with the inner periphery of the bottom end 3a of the cylinder body 3 in a liquid-tight state are interposed on the outer periphery of the upper and lower ends of the partition member 8.

  Incidentally, in the present invention, as will be described later, since the auxiliary damping portion 5 is disposed inside the partition wall member 8, the rods for holding the auxiliary damping portion 5 are shafts of the partition wall member 8. Do not penetrate the core.

  Then, the partition member 8 is retracted so as to rise in FIG. 2, and when the lower end position is finally retracted to the position indicated by symbol H in FIG. 2, the pressure receiving surface side of the partition member 8, that is, The pressure in the pressure side chamber R2 on the base valve portion 7 side accommodated in the cylinder body 3 is released to the outside of the cylinder body 3 to maintain the pressure in the cylinder body 3 in a constant state.

  At this time, as shown in the figure, the position indicated by the reference numeral H is the inner periphery of the bottom end portion 3a in the cylinder body 3 that is behind the position indicated by the reference numeral H, that is, the upper side in FIG. When the lower end of the partition member 8 is aimed at the expanded inner peripheral portion 3b, the inner peripheral portion where the pressure on the pressure receiving surface side of the partition member 8 is expanded. 3b and the communication hole 3c drilled in the inner peripheral portion 3b are released to the outside of the cylinder body 3.

  On the other hand, the partition member 8 is lowered in FIG. 2 by the pressurizing means arranged behind the partition member 8 in FIG. 2, ie, by the spring force of the coil spring 9 in the drawing. In addition to being advanced, the pressure in the pressure side chamber R2 in the cylinder body 3 is retracted to rise in FIG. 2 against the spring force of the coil spring 9 as the pressurizing means.

  At this time, as shown in the figure, the partition member 8 is lifted in FIG. 2 assuming that the back side of the partition member 8 is formed in an accumulator structure having an air chamber A with the oil level O as a boundary. When retreating, it is assumed that an air spring force is generated by the contraction of the air chamber A.

  Therefore, in the internal pressure ensuring means described above, the pressurizing means disposed behind the partition wall member 8 is composed of the coil spring 9 and the air chamber A. Therefore, the partition wall member 8 has a spring force in the coil spring 9. The air spring force in the air chamber A is affected.

  As a result, in the internal pressure guarantee means according to the present invention, the pressure on the back side of the partition wall member 8 can be ensured, while compared with the partition wall member disclosed in Patent Document 1 described above, This simplifies the configuration and makes it possible to reduce component costs.

  By the way, in the accumulator structure that constitutes the pressurizing means described above, the air spring force can be adjusted in level by adjusting the internal pressure in the chamber having the air chamber A by external operation. Of course, as long as that is the case, tuning to adjust the air spring force according to the rider's preference is possible.

  By the way, in the present invention, it is assumed that the auxiliary damping portion 5 is disposed in the inner oil of the partition wall member 8 described above, and at this time, the partition wall member 8 is cylinder-shaped as described above while being formed into a bottomed cylindrical shape. 3 is accommodated inside the bottom end 3a.

  The auxiliary attenuating portion 5 defines the inside of the partition member 8 in the partition member 8 that is a so-called pressure-receiving surface side, and the back side that is the opposite side, that is, the chamber side in the accumulator structure described above. The communication between the pressure receiving surface side and the rear side is allowed under the arrangement of the damping valve 5a and the extension side check valve 5b.

  At this time, the auxiliary attenuating portion 5 is a shaft that is present in a fixed state inside the partition wall member 8, that is, in the drawing, a view of the shaft 5c that is suspended from the shaft core portion of the inner tube 2 that is the vehicle body side tube. In this case, it is assumed that it is connected to the tip portion which is the lower end portion, so to speak, it is connected to the cylinder body 3 side in a fixed state to permit relative movement with the partition wall member 8.

  Therefore, in the auxiliary attenuating portion 5 disposed inside the partition member 8, the oil stored inside the partition member 8 is different in characteristics from the oil stored in the cylinder body 3. Thus, tuning according to the rider's preference can be realized by the auxiliary attenuation unit 5, so that the so-called width that can be tuned is widened, and the degree of freedom in tuning is increased.

  As described above, in the formed hydraulic shock absorber, when the internal pressure in the cylinder body 3 constituting the damper portion becomes abnormally high, this is released to the outside of the cylinder body 3. That is, the oil is returned into the cylinder body 3 through the head end portion of the cylinder body 3, that is, the opening end portion that causes the rod body 4 to protrude and retract, by repeatedly extending and retracting the damper portion. The oil shortage will not be a concern.

It is a figure which shows in principle the hydraulic shock absorber by this invention. It is a fragmentary longitudinal cross-sectional view which expands and shows the principal part in the hydraulic shock absorber of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Cylinder body 4 Rod body 5 Auxiliary damping part 5c Shaft 6 Piston part 7 Base valve part 8 Bulkhead member 9 Coil spring which is a pressurizing means A Air chamber which constitutes a chamber O Oil surface

Claims (4)

An outer tube (1), an inner tube (2) slidably fitted to the outer tube (1), a cylinder body (3) suspended from the upper end of the inner tube (2), and the outer tube A rod body (4) which is erected from the lower end of (1) and is slidably inserted into the cylinder body (3) via a piston section (6), and a base valve section provided in the cylinder body (3) (7), a bottomed cylindrical partition wall member (8) that is slidably inserted into the bottom end (3a) of the cylinder body (3) while facing the base valve portion (7), An expansion side chamber (R1) and a pressure side chamber (R2) separated by the piston portion (6) in the cylinder body (3), and a partition member (8) disposed on the opposite side of the pressure side chamber (R2). ) Is biased toward the compression side chamber (R2). In the hydraulic shock absorber provided with a communication hole (not shown), the cylinder body (3) is opened and closed by the partition member (8) to communicate or block the pressure side chamber (R2) and the outside of the cylinder body (3). 3c), and an auxiliary damping part (5) provided at the end of the shaft (5c) suspended from the upper end of the inner tube (2) is inserted into the partition member (8). Hydraulic shock absorber. An accumulator comprising oil in the cylinder body (3) behind the partition member (8) facing the pressure side chamber (R2) and an air chamber (A) above the oil level (O) of the oil. (Q) is separated, and when the air chamber (A) contracts, the partition member (8) is subjected to the action of the spring force of the coil spring (9) and the air spring force of the air chamber (A). The hydraulic shock absorber according to claim 1. The auxiliary damping part (5) is formed in the valve body (10) inserted into the partition member (8 ) and the oil in the accumulator (Q) and the separating member (8) formed in the valve body (10). The hydraulic shock absorber according to claim 2, comprising two ports communicating with the chamber (12), and a damping valve (5a) and an extension check valve (5b) provided in the respective ports so as to be opened and closed. vessel. The hydraulic shock absorber according to claim 2 or 3 , wherein a characteristic of the oil stored in the cylinder body (3) is different from a characteristic of the oil stored in the partition member (8).

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