JP5769556B2 - 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 as a front fork that is provided on the front wheel side of a motorcycle and absorbs vibration.

  There have been various proposals for a hydraulic shock absorber as a front fork that is provided on the front wheel side of a two-wheeled vehicle and absorbs vibrations. For example, in the proposal disclosed in Patent Document 1, the hydraulic shock absorber is the most suitable. It has an oil lock mechanism that alleviates impact during contraction operation.

  That is, in the hydraulic shock absorber disclosed in Patent Document 1, the fork main body composed of the vehicle body side tube and the wheel side tube has a damper set upright, and this damper has an oil lock mechanism.

  And in this hydraulic shock absorber, the oil lock mechanism has an oil lock case at the bottom end portion of the cylinder that is the lower end side member that constitutes the damper, and in the cylinder of the rod that is also the upper end side member that constitutes the damper. An oil lock piece made of a piston nut is provided at the tip as the lower end to be introduced.

  Therefore, in the hydraulic shock absorber disclosed in Patent Document 1, in the damper, the oil lock piece is fitted into the oil lock case at the time of the most contraction operation in the fork main body in which the rod enters the cylinder with a large stroke. become.

  At this time, resistance is generated by the working fluid in the oil lock case passing through the annular gap that appears between the oil lock piece and the oil lock case, and a cushion effect is obtained. The shock during the maximum contraction operation of the shock absorber is alleviated.

JP 2009-41687 A

  However, in the proposal disclosed in Patent Document 1 described above, the impact at the time of the most contraction operation is alleviated by the oil lock mechanism. However, depending on the mode of use, there is a risk that the hydraulic shock absorber may become inoperable. is there.

  That is, in the oil lock mechanism disclosed in Patent Document 1 described above, even if the oil lock piece fitted in the oil lock case is reversed and comes out of the oil lock case, this cannot be realized. Is concerned.

  In other words, the hydraulic shock absorber disclosed in the above-mentioned patent document 1 has a vehicle body weight that is smaller than a motorcycle that is a legally large vehicle or a medium-sized vehicle. And it is said that it is suitable for use on bicycles that run on human power.

  Therefore, in the oil lock mechanism described above, when this is embodied in a hydraulic shock absorber used in a motorcycle or a bicycle, the situation where the oil lock piece fits deeply into the oil lock case, that is, the oil lock It can also be said that it does not cause a situation in which the piece cannot get out of the oil lock case when the piece is reversed.

Therefore, the above oil lock mechanism does not have a configuration that allows the oil lock piece to be reversed after being deeply fitted in the oil lock case. deeply when fitted, the oil lock piece is expressed kuna Ru situation can escape from the oil lock case, there is a fear that the hydraulic shock absorber becomes inoperable.

  An object of the present invention is to provide a hydraulic shock absorber that has been created in view of the above-described present situation and that is not inoperable due to an oil lock mechanism that relieves shock during the most contraction operation.

To achieve the above object, the configuration of a hydraulic shock absorber according to the present invention, a cylinder is a wheel side tube, the lower end-side member by accommodating the working fluid into the disposed within the wheel side tube, the隔成a rod which is the upper end side member is and out freely through the cylinder, the inserted slidably into the cylinder upper chamber and lower chamber in the cylinder while being connected by a piston nut to the rod And a reservoir formed between the wheel side tube and the cylinder, and an oil lock piece comprising an oil lock piece comprising the piston nut and an oil lock case provided at the bottom end of the cylinder. in the hydraulic shock absorber is formed by, the cylinder has a communication hole that communicates the lower chamber and the reservoir, the OY The lock case has a flow path communicating with the reservoir, prevents the working fluid from flowing from the oil lock case to the reservoir through the flow path, and allows the working fluid to flow from the reservoir into the oil lock case. A check valve is provided, and the oil lock case has a sealing means on an inner peripheral side of an opening end portion that forms an opening for introducing the oil lock piece, and the oil lock piece is fitted in the oil lock case. The sealing means traps the working fluid in the oil lock case when the oil lock case is inserted, and prevents the working fluid from flowing into the oil lock case from the lower chamber when the oil lock piece escapes from the oil lock case. Suppose that it is allowed.

  Therefore, according to the present invention, in the oil lock mechanism, the oil lock piece is composed of a piston nut that connects the piston to the tip end of a rod that is inserted in and out of the cylinder, and the oil lock case is formed at the bottom end of the cylinder. Since the oil lock mechanism is provided between the head end of the cylinder and the base end of the rod that is above or near the base end, the working fluid that functions the oil lock mechanism It is possible to position the position of the fluid surface below the head end portion of the cylinder, and to reduce the amount of working fluid to be accommodated.

  And in this invention, in the oil lock mechanism, since the oil lock piece is composed of a piston nut that connects the piston to the tip of the rod, an oil lock case in the oil lock mechanism is provided at the head end of the cylinder, Therefore, the number of parts can be reduced as compared with the case where the oil lock piece in the oil lock mechanism is provided independently at or near the base end portion of the upper rod.

  Further, in the present invention, in the oil lock mechanism, since the oil lock case has the sealing means on the inner peripheral side portion of the opening end portion that forms the opening for introducing the oil lock piece, the oil lock piece is the oil lock case. When it fits in, the working fluid from the oil lock case passes through the annular gap that appears between the oil lock piece and the sealing means, and at this time, a cushion effect is obtained.

  Further, in the present invention, in the oil lock mechanism, the oil lock case has the sealing means on the inner peripheral side portion of the opening end portion that forms the opening for introducing the oil lock piece. When fitting into the case, the sealing means traps the working fluid in the oil lock case, and the oil lock function is demonstrated so that the oil lock piece does not fit further into the oil lock case. Bottom thrust is avoided.

  Furthermore, in the present invention, when the oil lock piece fitted in the oil lock case comes out of the oil lock case in the oil lock mechanism, the sealing means is the oil of the working fluid from the lower chamber. Since the inflow into the lock case is allowed, it is possible to avoid an inoperable state of the hydraulic shock absorber that prevents the oil lock piece from coming out of the oil lock case.

  As a result, according to the present invention, the hydraulic shock absorber is not brought into an inoperable state by the oil lock mechanism that reduces the impact during the most contracted operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. It is a semi-longitudinal longitudinal cross-sectional view which shows the intermediate part in the hydraulic shock absorber by one Embodiment of this invention. FIG. 3 is a semi-longitudinal longitudinal sectional view showing a lower end side portion of the hydraulic shock absorber shown in FIG. 2.

  The present invention will be described below with reference to the drawings. In the drawings, the hydraulic shock absorber according to the present invention is provided on the front wheel side of a two-wheeled vehicle, and is a front fork that absorbs vibration during traveling. The

  As shown in FIG. 1, the front fork includes a fork main body (not shown) in which a vehicle body side tube 1 serving as an upper end side member and a wheel side tube 2 serving as a lower end side member are connected in a telescopic manner. ).

  Further, the fork main body has a damper (not shown) set upright on the shaft core, and the damper has a damping mechanism (not shown) so as to have a predetermined damping action during the expansion / contraction operation. In addition, an oil lock mechanism (not shown) is provided to alleviate the impact during the most contracted operation.

  Incidentally, in this fork main body, the opening end portion which is the lower end portion of the vehicle body side tube 1 is used as a seal case portion (not shown), and a seal member on the inner peripheral side portion, that is, in the place shown in FIG. The seal 11 and the dust seal 12 are provided. The oil seal 11 prevents the working fluid represented by the hydraulic oil from the inside of the fork main body from leaking out of the fork main body, and the dust adhered to the outer periphery of the wheel side tube 2 by the dust seal 12. Is prevented from entering the inside of the fork main body, that is, the oil seal 11 side.

  In addition, the fork main body has a lower bearing 13 whose inner periphery is in sliding contact with the outer periphery of the wheel side tube 2 on the inner peripheral side portion at the opening end of the vehicle body side tube 1, and the upper end portion of the wheel side tube 2. 1 has an upper bearing 21 (see FIG. 1) whose outer periphery is in sliding contact with the inner periphery of the vehicle body side tube 1, and the concentricity of the wheel side tube 2 with respect to the vehicle body side tube 1 by both bearings 13, 21. And slidability is guaranteed.

  A gap formed between both the bearings 13 and 21 and the vehicle body side tube 1 and the wheel side tube 2 is defined as a lubrication gap S, and a communication hole opened in the wheel side tube 2 in the lubrication gap S. The working fluid from the inside of the wheel side tube 2 flows as a lubricant through 2a (see FIG. 1), thereby ensuring lubricity between the vehicle body side tube 1 and the wheel side tube 2.

  By the way, the fork main body shown in the figure does not have a suspension spring in the air chamber A (see FIG. 1) separated from the reservoir R in the fork main body by the fluid surface O (see FIG. 1) of the working fluid. 1), that is, when the fork main body is in the most extended state, the air pressure that is equal to or higher than the atmospheric pressure is energized in the air chamber A to be urged in the extending direction.

  Therefore, this fork main body does not have a suspension spring as an urging element in the extending direction, which contributes to a reduction in the overall weight of the front fork.

  In the fork main body, the air spring force based on the air pressure in the air chamber A overcomes the contraction operation, and the fork main body expands by the air spring force, and the damper expands and contracts in synchronization with the expansion and contraction operation of the fork main body. .

  Returning to FIG. 1, the fork main body is set to be an inverted type in which the vehicle body side tube 1 is made of a large diameter outer tube and the wheel side tube 2 is made of a small diameter inner tube.

  However, from the point of view of the present invention, although not shown, instead of setting the fork main body in an inverted type, the inner tube is the vehicle body side tube 1 which is the upper end side member, and the outer tube is the lower end side member. The wheel side tube 2 may be set upright.

  Further, as shown in FIG. 3, an axle holder 22 as a bottom member is connected to the lower end portion of the wheel side tube 2, and this axle holder 22 is a bracket for connecting the lower end portion of the fork main body to the axle of the front wheel of the motorcycle. Furthermore, the lower end part of the cylinder 3 which comprises the lower end part in the damper mentioned later is introduced inside.

  At this time, as shown in FIG. 3, a seal holder 23 is sandwiched between the lower end of the wheel side tube 2 and an inner peripheral step (not shown) in the axle holder 22. 2 has a seal 23a adjacent to the inner periphery of the lower end portion and a seal 23b adjacent to the inner periphery of the inner peripheral step portion of the wheel side tube 2 to ensure liquid tightness between the two.

  Although not shown, the vehicle body side tube 1 has a cap member that detachably closes the upper end opening of the vehicle body side tube 1 at the upper end portion, and this cap member constitutes a later-described damper at the shaft core portion. The upper end of the rod 4 is connected.

  Therefore, in this fork body, when the cap member is separated from the upper end of the vehicle body side tube 1, the vehicle body side tube 1 can be lowered, and the rod 4 and the wheel side tube in the damper connected to the cap member. 2 can be exposed, and for example, the amount of working fluid accommodated in the fork body, that is, the height position of the fluid surface O separating the air chamber A can be adjusted. Become.

  On the other hand, as shown in FIG. 1, the damper is installed on the shaft core portion of the wheel-side tube 2, and is provided on the shaft core portion of the vehicle body-side tube 1. A rod 4 that is suspended and serves as an upper end side member, and a tip end side that is the lower end side in the drawing is inserted into the cylinder 3 so as to be freely inserted and removed, and a lower end of the rod 4 that is slidably inserted into the cylinder 3 in the drawing. The cylinder 3 has a piston 5 which is held by a leading end (not shown) as a part and separates the upper chamber R1 and the lower chamber R2.

  At this time, in this invention, a piston nut (not shown) that connects the piston 5 to the tip of the rod 4 constitutes an oil lock piece 61 in the oil lock mechanism 6 described later. It will be described later.

  In this damper, the cylinder 3 has a rod guide 31 at the head end (not shown) which is the upper end in FIG. 1, and the rod guide 31 closes the upper end opening of the cylinder 3. The rod 4 is passed through the shaft core.

  The cylinder 3 has a spring holder 32 formed in an annular shape between the rod guide 31 and an inner peripheral step (not shown) in the cylinder 3 below the rod guide 31. An extension spring S1 that is arranged and interposed in the rod 4 and a balance spring S2 that is arranged on the outer peripheral side and provided on the inner periphery of the cylinder 3 are suspended.

  Note that the lower end of the extension spring S1 is carried by a spring receiver 41 that is held fixed on the outer periphery of the rod 4 on the lower side, that is, in a snap ring 41a that is fitted to the rod 4 as shown in FIG. It faces the spring receiver 41.

  On the other hand, as shown in FIG. 1, an annular spring sheet 33 is held at the lower end of the balance spring S2, and this spring sheet 33 is placed at the upper end of the lower piston 5, that is, as shown in FIG. Is opposed to a spring stopper 34 carried on a portion constituting a damping mechanism in the piston 5 described later.

  Therefore, when the rod 4 rises in the cylinder 3 with a large stroke and reaches the maximum extension state, the extension spring S1 contracts by the contact of the spring receiver 41 to exert a spring force, and the damper is extended most. Mitigates shock during operation.

  The balance spring S2 is contracted by the contact of the spring stopper 34 to the spring seat 33 and contracts the spring force, that is, the damper, when the rod 4 rises in the cylinder 3 with a large stroke and reaches the maximum extension state. Demonstrate the spring force biased in the direction.

  That is, the illustrated front fork is energized in the extending direction by enclosing a pressure higher than atmospheric pressure in the air chamber A in the reservoir R when the fork main body is in the most extended state, thereby providing a reaction force. Therefore, the reaction force during the contraction operation in the predetermined stroke region from the maximum extension state can be reduced by suppressing the reaction force in the predetermined stroke region in which the fork main body contracts from the maximum extension state by the balance spring S2. It becomes possible.

  By the way, in this damper, the lower end portion of the cylinder 3 is a bottom end portion (not shown), and an oil lock case 62 constituting an oil lock mechanism 6 described later is provided at the bottom end portion.

  The oil lock case 62 closes the lower end opening of the cylinder 3, and in the place shown in FIG. 3, the bottom portion (not shown) of the axle holder 22 passes through the seal 62a and passes through the bottom of the cylinder 3. Screwed to the bottom end.

  Therefore, in the place shown in FIG. 3, although not shown, the oil lock case is in a position to be seated on the bottom portion of the axle holder by tightening the fastening bolt that penetrates the shaft core portion of the bottom portion of the axle holder. This is advantageous in that the number of parts required for fixing the oil lock case 62 can be reduced as compared with the case where it is used.

  A communication hole 3a (see FIGS. 1 and 3) allowing communication between the lower chamber R2 inside the cylinder 3 and the reservoir R outside the cylinder 3 is slightly above the bottom end portion to which the oil lock case 62 in the cylinder 3 is connected. ).

  The communication hole 3a may have a damping action when the working fluid passes through, for example, an orifice, depending on the configuration of a damping mechanism in the piston 5 to be described later, and may not be a noticeable damping action. It may be a hole.

  Therefore, in the cylinder 3 having the communication hole 3a described above, an amount of working fluid corresponding to the rod intrusion volume that becomes redundant in the lower chamber R2 when the damper 5 in which the piston 5 descends in the cylinder 3 is contracted. The outflow to the reservoir R outside the cylinder 3 through the communication hole 3a is allowed.

  In the cylinder 3 having the communication hole 3a, an amount of working fluid corresponding to the rod withdrawal volume integral that is insufficient in the lower chamber R2 when the damper 5 in which the piston 5 moves up in the cylinder 3 is operated. Is allowed to flow into the lower chamber R2, that is, from the reservoir R outside the cylinder 3.

  If the oil lock case 62 is provided at the bottom end portion of the cylinder 3, the replenishment of the working fluid from the reservoir R to the lower chamber R2 is as shown in FIG. 62 may be realized by including the check valve C.

  That is, a check valve C that prevents the working fluid from passing from the oil lock case 62 toward the reservoir R, but allows the working fluid from the reservoir R to flow into the oil lock case 62 in the opposite direction. May be provided in the oil lock case 62.

  In this case, even when the communication hole 3a provided in the cylinder 3 is an orifice and restricts the passage of the working fluid, it does not cause a problem of insufficient suction of the working fluid in the lower chamber R2 when the damper is extended. There is an advantage that becomes possible.

  The rod 4 basically only needs to connect the piston 5 slidably inserted into the cylinder 3 to the tip portion which is the lower end portion in FIG. 1. Although it is good, as shown in FIG. 2, you may form with a hollow body, ie, a pipe.

  When the rod 4 is formed of a pipe, it is possible to increase the bending strength while reducing the weight as compared with the case where the rod 4 is formed of a solid body. In particular, as shown in FIG. In addition, the control rod 42 can be disposed inside, and the use of the control rod 42 is advantageous in that the level of the damping action in the damping mechanism can be adjusted.

  Incidentally, in the place shown in FIG. 2, the control rod 42 itself is also made of a pipe, allowing the weight of the control rod 42 to be reduced and improving the bending strength. The valve 43 is disposed in a bypass path L that communicates the lower chamber R2 and the upper chamber R1 in the cylinder 3 with bypassing a later-described damping mechanism.

  2, the bypass L is opened in the lower chamber R2 through a piston nut, which will be described later, and is opened at the shaft core of the tip member 44 constituting the tip of the rod 4. A vertical hole 44a and a lateral hole 44b whose one end is open to the upper chamber R1, and a tip (not shown) at the tip of the control valve 43 is the upper end in the figure of the vertical hole 44a. Present at the end opening.

  Therefore, in this control valve 43, although it is via the control rod 42, when moving in the vertical direction in the figure, the flow rate of the working fluid passing through the bypass L can be somewhat increased, and therefore the damping mechanism The flow rate of the working fluid in can be made somewhat, and the damping action by the damping mechanism can be adjusted in level.

  As shown in FIG. 2, when the control valve 43 is provided in the bypass passage L, the damping action that the control valve 43 adjusts is adjusted by the piston 5 constituting the damping mechanism described later. Attenuating action is achieved by the extension side damping valve 51 or the pressure side damping valve 52.

  As shown in FIG. 1, the piston 5 is slidably inserted into the cylinder 3. As shown in FIG. 2, the piston 5 is interposed in the tip member 44 of the rod 4 and has an upper chamber R 1 and a lower chamber in the cylinder 3. Separated from R2.

  The piston 5 has a damping mechanism that performs a predetermined damping action when the piston 5 slides in the cylinder 3 to allow communication between the upper chamber R1 and the lower chamber R2.

  That is, the damping mechanism in the piston 5 has an expansion side damping valve 51 (see FIG. 2) and a pressure side damping valve 52 as damping means, and the pressure side damping valve 52 is opened in the piston 5 as shown in FIG. It comprises a laminated annular leaf valve that closes the downstream end of the pressure side passage 5a so as to be openable.

  The extension side damping valve 51 is also composed of a laminated annular leaf valve that closes the downstream end of the extension side passage (not shown) of the piston 5 so as to be openable, as shown in FIG.

  The piston 5 is held at the tip of the rod 4 by a piston nut (not shown) that is screwed into a tip screw (not shown) of the tip member 44. At this time, the piston nut is 2 has an oil passage (not shown) that forms an end of the above-described bypass passage L on the lower chamber R2 side.

  By the way, in the present invention, the piston nut constitutes the oil lock piece 61 in the oil lock mechanism 6. Therefore, in this piston nut, the portion to be screwed into the tip screw portion of the tip member 44. Is a nut portion (not shown), and a portion fitted into the oil lock case 62 is a tip portion (not shown), and this tip portion substantially constitutes an oil lock piece.

  From this point of view, the tip of the oil lock piece 61 may be provided with a taper 61a along the axial direction of the cylinder 3 on the outer periphery, as shown in FIG. In view of having the sealing means described later, it may be formed in a substantially cylindrical shape or a cylindrical shape having no conspicuous taper.

  Therefore, in the damper having the cylinder 3, the rod 4 and the piston 5 formed as described above, the working fluid in the upper chamber R1 is expanded on the expansion side damping valve when the piston 5 moves up in the cylinder 3. The gas flows out into the lower chamber R2 through 51, and at this time, a predetermined expansion side damping action is performed by the expansion side damping valve 51.

  At this time, an amount of working fluid corresponding to the rod withdrawal volume that is insufficient in the lower chamber R2 is replenished from the reservoir R via the communication hole 3a, and when the communication hole 3a is an orifice, a damping action on the extension side Is made.

  Further, in this damper, during the contraction operation in which the piston 5 descends in the cylinder 3, the working fluid in the lower chamber R2 flows into the upper chamber R1 through the passage 5a opened in the piston 5, The compression side damping valve 52 performs a predetermined compression side damping action.

  At this time, the working fluid in an amount corresponding to the rod intrusion integral that becomes excessive in the lower chamber R2 flows out to the reservoir R through the communication hole 3a opened in the cylinder 3, and the communication hole 3a is made an orifice. Sometimes, a compression side damping action is performed.

  As shown in FIG. 1, the oil lock mechanism 6 includes an oil lock piece 61 including a piston nut that connects a piston 5 to a tip end of a rod 4 that is removably inserted into the cylinder 3, and a bottom end portion of the cylinder 3. And an oil lock case 62 provided on the front side.

  Therefore, in the oil lock mechanism 6, the oil lock piece 61 is composed of a piston nut, and the oil lock case 62 is provided at the bottom end portion of the cylinder 3. And the position of the fluid surface O (see FIG. 1) in the working fluid that causes the oil lock mechanism 6 to function as compared with the case where it is provided between the base end of the rod 4 and the vicinity of the base end. 3 can be positioned below the head end portion of the head 3, and the amount of the working fluid to be accommodated can be reduced, thereby reducing the weight of the front fork.

  In the oil lock mechanism 6, the oil lock piece 61 is composed of a piston nut that connects the piston 5 to the tip of the rod 4. However, although not shown, an oil lock case in the oil lock mechanism is provided at the head end of the cylinder. Therefore, the piston nut and the oil lock piece are formed as separate parts compared to the case where the oil lock piece in the oil lock mechanism is provided alone at or near the base end of the rod 4 that is on the upper side. Without reducing the number of parts.

  In addition to this, in the oil lock mechanism 6, compared to the case where the oil lock piece is provided at or near the base end of the rod 4, the effective stroke of the rod 4 outside the cylinder 3, that is, There is an advantage that the effective stroke of the rod 4 constituting the damping mechanism in the piston 5 can be greatly increased.

  On the other hand, in the oil lock mechanism 6, the oil lock case 62 has a sealing means (not shown) on an inner peripheral side portion of an opening end portion that forms an opening for introducing the oil lock piece 61.

  The sealing means confines the working fluid in the oil lock case 62 when the oil lock piece 61 comes into the oil lock case 62, and also when the oil lock piece 61 comes out of the oil lock case 62. The hydraulic fluid from the lower chamber R2 is allowed to flow into the oil lock case 62.

  At this time, as shown in FIG. 3, the sealing means includes an annular groove 62b formed on the inner peripheral side portion of the opening end of the oil lock case 62, a radial direction in the annular groove 62b, and an axial direction of the rod 4. An oil seal case 62 is inserted so as to be movable in the axial direction, and has an annular seal 63 that allows the oil lock case 61 to be fitted to the inner peripheral side.

  In this sealing means, the annular seal 63 has a notch that allows communication between the inner peripheral side and the outer peripheral side of the annular seal 63 on the end surface facing the lower chamber R2, that is, the upper end surface in FIG. When the end face opposite to the end face having the passage 63a, that is, the lower end face in FIG. 3 is seated on the inner wall 62c of the annular groove 62b opposite to the lower end face, the annular seal 63 is provided. Communication between the inner peripheral side and the outer peripheral side is prevented.

  Therefore, in this oil lock mechanism 6, the oil lock case 62 has sealing means on the inner peripheral side of the opening end portion that forms the opening for introducing the oil lock piece 61. When the oil lock case 62 is fitted, the working fluid from the oil lock case 62 passes through the annular gap that appears between the oil lock piece 61 and the sealing means. can get.

  In this oil lock mechanism 6, since the oil lock case 62 has a sealing means on the inner peripheral side of the opening end portion that forms the opening through which the oil lock piece 61 is introduced, the oil lock piece 61 is placed in the oil lock case 62. The sealing means traps the working fluid in the oil lock case 62 when fitting into the oil lock case 62, and the oil lock function is exerted so that the oil lock piece 61 does not fit further into the oil lock case 62. A bottom butt is avoided in the front fork.

  Further, in this oil lock mechanism 6, when the oil lock piece 61 fitted in the oil lock case 62 comes out of the oil lock case 62, the sealing means is separated from the side wall 62c of the annular groove 62b. Since the inflow of the working fluid from the lower chamber R2 into the oil lock case 62 is allowed, it is possible to avoid a damper that prevents the oil lock piece 61 from coming out of the oil lock case 62, that is, an inoperable state of the front fork. .

  Incidentally, in the oil lock mechanism 6 described above, the oil lock piece 61 has a sealing means that is held on the inner peripheral side of the opening end of the oil lock case 62, and an annular seal 63 that constitutes this sealing means. Since the cushion effect is obtained when the oil lock piece 61 comes into sliding contact with the oil lock piece 61, compared to the case where the cushion effect can be obtained by directly fitting the oil lock piece 61 into the oil lock case 62. Even if there is a so-called error in the radial direction between the oil lock piece 61 and the oil lock case 62, there is an advantage that a predetermined cushion effect can be exhibited.

  As described above, in the front fork according to the present invention, the fork main body accommodates the working fluid therein and serves as the lower end side member, and the upper end side member is inserted into the cylinder 3 so as to freely enter and exit. And a piston 5 connected to the rod 4 by a piston nut and slidably inserted into the cylinder 3 to separate the upper chamber R1 and the lower chamber R2 into the cylinder 3. Therefore, a predetermined damping action can be performed by the damping mechanism when the damper is extended or contracted.

  In the front fork according to the present invention, the oil lock piece 61 constituting the oil lock mechanism 6 in the damper is composed of a piston nut that connects the piston 5 to the tip of the rod 4 that is removably inserted into the cylinder 3. Since the oil lock case 62 is provided at the bottom end portion of the cylinder 3, the oil lock mechanism 6 can alleviate the impact by the oil lock mechanism 6 when the damper is fully contracted, and the oil lock mechanism is connected to the head end portion of the cylinder 3. The position of the fluid surface O in the working fluid that causes the oil lock mechanism 6 to function is higher than the position of the head end of the cylinder 3 as compared with the case where it is provided between the base end of the rod 4 and the vicinity of the base end. It is possible to position it downward, and the amount of working fluid that can be stored can be reduced. Kicking enables mitigation of weight, also because oil lock piece 61 is formed of a piston nut, it is possible to reduce the number of parts.

  On the other hand, in the front fork according to the present invention, the oil lock case 62 constituting the oil lock mechanism 6 has sealing means on the inner peripheral side portion of the opening end portion that forms an opening for introducing the oil lock piece 61. When the oil lock piece 61 is fitted in the oil lock case 62, the sealing means confines the working fluid in the oil lock case 62. Therefore, an annular gap that appears between the oil lock piece 61 and the seal means is removed from the oil lock case 61. The working fluid from inside 62 passes, and at this time, a cushion effect is obtained.

  In the front fork according to the present invention, when the oil lock piece 61 is fitted into the oil lock case 62, the sealing means confines the working fluid in the oil lock case 62, and the oil lock function is exerted so that the oil lock piece is exhibited. No more 61 fits into the oil lock case 62, and the bottom of the hydraulic shock absorber is avoided.

  Further, in the front fork according to the present invention, when the sealing means comes out of the oil lock case 62 from the oil lock piece 61, the working fluid flows into the oil lock case 62 from the lower chamber R2 in the cylinder 3. Therefore, it is possible to avoid an inoperable state of the hydraulic shock absorber that prevents the oil lock piece from coming out of the oil lock case.

  In the above description, the oil lock case 62 constituting the oil lock mechanism 6 is a separate part and is connected to the bottom end of the cylinder 3. Instead, for example, although not shown, The bottom end of the cylinder 3 may be an oil lock case. In this case, the oil lock piece 61 constituting the oil lock mechanism 6 in the present invention connects the piston 3 to the tip of the rod 4. The piston nut is advantageous in that it allows for further parts reduction in addition to enabling so-called parts reduction.

DESCRIPTION OF SYMBOLS 1 Car body side tube 2 Wheel side tube 2a, 3a Communication hole 3 Cylinder 4 Rod 5 Piston 5a Pressure side passage 6 Oil lock mechanism 11 Oil seal 12 Dust seal 13 Lower bearing 21 Upper bearing 22 Axle holder 23 Seal holder 23a, 23b Seal 31 Rod guide 32 Spring holder 33 Spring seat 34 Spring stopper 41 Spring receiver 41a Snap ring 42 Control rod 43 Control valve 44 Tip member 44a Vertical hole 44b Horizontal hole 51 Extension side damping valve 52 Pressure side damping valve 61 Oil lock piece 61a taper 62 Oil lock case made of piston nut 62a Seal 62b Annular groove 62c constituting the sealing means 62c Inner wall 63 Annular seal constituting the sealing means 63a Passage A Air chamber O Fluid surface R On the reservoir R1 Direction chamber R2 Lower chamber S Lubrication gap S1 Stretch spring S2 Balance spring

Claims (3)

And the wheel side tube, a cylinder that is being brought to the lower end side member accommodating a working fluid into the disposed within the wheel side tube, and a rod that is the upper end side member is inserted freely and out to the cylinder, the rod A piston that is slidably inserted into the cylinder and that separates the upper chamber and the lower chamber, and a reservoir formed between the wheel side tube and the cylinder. A hydraulic shock absorber comprising an oil lock piece comprising an oil lock piece comprising the piston nut and an oil lock case provided at the bottom end of the cylinder;
The cylinder has a communication hole for communicating the lower chamber and the reservoir,
The oil lock case has a flow path communicating with the reservoir, prevents the working fluid from flowing from the oil lock case to the reservoir through the flow path, and flows the working fluid from the reservoir into the oil lock case. Provide a check valve that allows
The oil lock case has sealing means on an inner peripheral side portion of an opening end portion that forms an opening for introducing the oil lock piece;
When the oil lock piece fits in the oil lock case, the sealing means traps the working fluid in the oil lock case, and when the oil lock piece escapes from the oil lock case, A hydraulic shock absorber, wherein a working fluid is allowed to flow into the oil lock case. And the annular groove forming the sealing means on the inner peripheral side of the opening end portion of the oil lock case movably in the axial direction of the oil lock case formed to the axial direction of the radial direction and the rod in the annular groove An annular seal that is inserted and allows the oil lock case to be fitted into the inner periphery,
The end surfaces of the annular seal is located on the side opposite to the end face having the passageway and having a passageway to allow communication between the inner and outer peripheries of the annular seal on the end face opposite to the lower chamber is opposed to the end face hydraulic shock absorber according to claim 1 obtained by blocking the communication between the inner and outer peripheries of the annular seal when seated on the inner wall of the annular groove.   The cylinder is erected on a shaft core portion of a wheel side tube which is a lower end side member, and the rod is telescopically connected to the wheel side tube and is suspended from a shaft core portion of a vehicle body side tube which is an upper end side member. The hydraulic shock absorber according to claim 1 or 2, wherein the hydraulic shock absorber is provided.

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