JP2009127845A - Oil lock structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To desirably relieve shock while assuring desired damping action. <P>SOLUTION: A piston body 4 is stored in a cylinder body 3 which forms a double-rod damper stored in the core part of a fork body comprising a vehicle body side tube 1 and a wheel ring side tube 2. The proximal end of a lower rod body 52 is connected to the piston body, and the distal end thereof projects downward from the bottom end 31b of a cylinder body 3. The lower rod body holds an oil lock piece 6 in a lower oil chamber R2 formed by the piton body 4 in the cylinder body 3 and also holds an oil lock case 7 which fits the oil lock piece 6 to the bottom end 31b of the cylinder body 3 through which the lower rod body 52 extends. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an oil lock structure, and more particularly to an oil lock structure suitable for implementation in a front fork as a hydraulic shock absorber that is mounted on the front wheel side of a motorcycle and absorbs road surface vibrations input to the front wheel while the front wheel is suspended. Regarding improvements.

  As is well known, a double rod type damper, in principle, does not require a so-called reservoir as compared to a single rod type damper, and therefore it can be expected to generate a stable damping force without fear of aeration. .

  There are various proposals for a front fork that incorporates this double rod type damper, but it is important to take measures to alleviate the impact when the front fork is contracted most.

  As a measure for mitigating the impact when the front fork is most contracted, for example, there is a proposal to mitigate the impact by contracting the rubber material. However, in the oil lock structure using the working fluid, the rubber material is contracted when the rubber material is contracted. There is no generation of repulsive force, and the impact can be reduced in a preferable state.

  Therefore, there is a proposal of a front fork provided with this oil lock structure. For example, in the proposal disclosed in Patent Document 1, a cylinder serving as a lower end side member in an upright damper disposed in a front fork is provided. An oil lock structure is provided between the upper end of the body and the rod body that is inserted into the cylinder body so as to be able to appear and retract.

  That is, an oil lock case that is formed in a substantially bottomed cylindrical shape and opens upward is held at the upper end portion of the cylinder body, and the above oil lock is placed on the outer periphery of the rod body that protrudes upward from the upper end portion of the cylinder body. An oil lock piece that fits into the case is held.

  The rod body passes through the shaft core at the bottom of the oil lock case, and a check valve is provided at the bottom to allow inflow of hydraulic oil from outside the oil lock case into the oil lock case. .

Therefore, in this oil lock structure, when the front fork is most contracted and the rod body is immersed in the cylinder body with a large stroke, the oil lock piece held by the rod body is inserted into the oil lock case. Then, the hydraulic oil is trapped in the oil lock case, and the impact at the time of the maximum contraction operation of the front fork is mitigated.
JP 2002-122173 A (see paragraphs 0002 to 0004, FIGS. 3 and 4 in the specification)

  However, the oil lock structure disclosed in Patent Document 1 described above is not necessarily defective in its operation, but there is a possibility that it may be pointed out that there is a slight problem in ensuring the desired impact mitigating action. is there.

  That is, in the above-described front fork, the oil lock case constituting the oil lock structure protrudes upward along the axial direction of the rod body from the upper end portion of the cylinder body. Forming a reservoir in the front fork.

  The reservoir contains a predetermined amount of hydraulic oil and has an air chamber bordered by the oil surface. This air chamber expands and contracts when the front fork expands and contracts, and exhibits an air spring force. Thus, the oil level is likely to be disturbed when the front fork extends and contracts.

  When the oil level is disturbed in the reservoir, air is mixed into the hydraulic oil. When the hydraulic oil enters the oil lock case, the oil lock effect is set by fitting the oil lock piece. There is a problem that the desired impact mitigating action cannot be sufficiently ensured.

  The present invention was devised in view of such a current situation, and the object of the present invention is to ensure desired damping action as well as desired damping action. It is an object of the present invention to provide an oil lock structure that is optimal for expecting improved versatility in the front fork.

  In order to achieve the above-described object, the oil lock structure according to the present invention basically has a double rod type damper mounted on the shaft core portion of the fork main body composed of the vehicle body side tube and the wheel side tube. The cylinder body to be formed is disposed in the wheel side tube, and the upper rod body in the rod body forming the damper is suspended from the vehicle body side tube while penetrating the upper end portion of the main body portion of the cylinder body and is accommodated in the main body portion. The lower rod body in the rod body that is connected to the piston body and is connected to the piston body that is housed in the main body while passing through the lower end of the main body is projected to the lower side of the main body. The lower rod body is located in the lower oil chamber defined by the piston body in the main body, holds the oil lock piece, and passes through the lower rod body. The oil lock case for fitting the oil lock piece to the lower end of the main body is held.

  Therefore, according to the present invention, the oil lock structure is defined by the piston body in the cylinder body of the double rod type damper that is housed in the shaft core portion of the fork main body including the vehicle body side tube and the wheel side tube. Because it is provided in the oil chamber, it does not allow hydraulic oil to enter the oil lock case that constitutes the oil lock structure, and the oil lock piece fits in the oil lock case to achieve a predetermined impact. Mitigation can be achieved.

  Hereinafter, the present invention will be described based on an embodiment shown in FIG. 1 which is a principle diagram and FIG. 2 which is a specific diagram of a main part. An oil lock structure according to the present invention includes a wheel side tube 2 in a vehicle body side tube 1. Is embodied in a front fork in which a double rod type damper is housed in a shaft core portion of a fork main body that is inserted so as to be able to appear and retract.

  The fork main body accommodates a double rod type damper, which will be described later, in the shaft core portion, while the inside is a reservoir chamber R, and an air chamber A (see FIG. 1) bordering on the oil level O (see FIG. 1). This air chamber A exhibits an air spring force when the fork body is contracted.

  In this fork main body, the rod body 5 in the double rod type damper, that is, the upper rod body 51 is suspended from the shaft core portion of the vehicle body side tube 1, and the wheel core tube 2 has a shaft core portion. The cylinder body 3 which forms this double rod type damper is also arranged.

  The upper end of the rod body 5, that is, the upper end of the upper rod body 51 is connected to a cap portion 1 a (see FIG. 1) that closes the upper end opening of the vehicle body side tube 1, and the cylinder body 3 includes a sub cylinder portion 32 described later. It connects with the bottom part 2a (refer FIG. 1) which obstruct | occludes the lower end opening of the wheel side tube 2 via.

  The suspension spring S is shown in the figure and is disposed between the cylinder body 3 and the vehicle body side tube 1, and the spring side forces the wheel side tube 2 out of the vehicle body side tube 1. The fork body is urged in the extending direction.

  On the other hand, the double rod type damper has the cylinder body 3, the piston body 4, and the rod body 5, that is, the upper rod body 51 and the lower rod body 52. An oil lock piece 6 and an oil lock case 7 constituting an oil lock structure are provided.

  If it demonstrates a little, the cylinder body 3 has the main-body part 31 which accommodates the piston body 4 so that sliding is possible, and this body part 31 is provided inside by providing the upper end part 31a and lower end part 31b as a bearing part. The oil chamber space is defined.

  Therefore, in the illustrated front fork, the inside of the main body portion 31 of the cylinder body 3 forming the double rod type damper is not in fear of the occurrence of aeration due to having the reservoir chamber R in principle.

  That is, as is well known, in the single rod type damper, the pressure side oil chamber in the cylinder body communicates with the reservoir chamber outside the cylinder body, and particularly when the hydraulic oil is insufficient in the pressure side oil chamber, it operates from the reservoir chamber. Oil is replenished.

  Therefore, when air is mixed into the hydraulic oil due to the oil level being disturbed in the reservoir chamber, the hydraulic oil mixed with the air flows into the pressure side oil chamber in the cylinder body, and the aeration of the aeration is performed in the pressure side oil chamber. Occurrence is feared.

  However, in the double rod type damper incorporated in the front fork of the present invention, since the hydraulic oil does not reciprocate between the cylinder body 3 and the outside of the cylinder body 3, even if the reservoir chamber R is provided, the aeration of Do not worry about the occurrence.

  By the way, in this cylinder body 3, the sub cylinder part 32 which defines sub oil chamber R3 which makes the front end side of the lower rod body 52 mentioned later exist is connected with the lower end part 31b in the main-body part 31.

  The sub-cylinder portion 32 is erected on the shaft core portion of the wheel side tube 2 while extending from the main body portion 31 to the same diameter, and the opening end serving as the lower end is closed by the bottom portion 2 a of the wheel side tube 2. In addition, the inside is communicated with the outside of the sub-cylinder portion 32, that is, the above-described reservoir chamber R through a communication hole 32a (see FIG. 1) provided at the lower end.

  Incidentally, although not shown, the main body 31 of the cylinder body 3 has a small hole at a position near the upper end 31a, and air mixed into the hydraulic oil in the upper oil chamber R1 through this small hole is stored in the reservoir chamber. You may be allowed to exit R.

  The piston body 4 is slidably accommodated in the main body 31 in the cylinder body 3 and defines an upper oil chamber R1 and a lower oil chamber R2 that do not have a pressure receiving area difference in the main body 31. In addition, an expansion side damping valve 41 and a pressure side damping valve 42 that generate a damping force of a predetermined magnitude while allowing communication between both the oil chambers R1, R2 are provided.

  The rod body 5, that is, the upper rod body 51 and the lower rod body 52 are connected to both ends of the piston body 4, which are upper and lower ends in FIG. The upper end opening or the lower end opening is closed, and the shaft portion of the upper end portion 31a or the lower end portion 31b, which is a bearing portion, is penetrated and protrudes outward in the axial direction of the main body portion 31.

  The upper end of the upper rod 51 in the figure is connected to the vehicle body side tube 1, but the lower end of the lower rod 52 in the figure is the lower end of the main body 31 as described above. It penetrates 31b and protrudes into the sub oil chamber R3 in the sub cylinder part 32.

  The upper end 31a and the lower end 31b of the main body 31 have a bearing member (not shown), and the slidability of the upper rod body 51 and the lower rod body 52 is ensured by this bearing member.

  Since the bearing member allows sliding leakage of the hydraulic oil with respect to the rod body 5, the hydraulic oil mixed with air in the upper oil chamber R1 defined in the main body 31 of the cylinder body 3 is It flows out of the cylinder body 3, that is, into the reservoir chamber R through the inner peripheral side of the bearing member.

  Therefore, in the above-described double rod type damper, when the piston body 4 slides within the main body 31 in the cylinder body 3, both the oil chambers R1, R2 are communicated with each other via the damping valves 41, 42. , A predetermined damping force on each side is generated.

  For this reason, in this front fork, the fork main body expands and contracts while a predetermined damping force is generated on each side by the expansion and contraction operation of the built-in double rod type damper.

  The oil lock piece 6 is formed in an annular shape and is held by an appropriate means on the outer periphery of the lower rod body 52 that faces the lower oil chamber R2 in the main body 31 of the cylinder body 3.

  On the other hand, the oil lock case 7 forming the oil lock structure is held by the lower end portion 31b of the main body portion 31 that penetrates the lower rod body 52, and the oil lock piece 6 is fitted inside.

  The oil lock case 7 is formed in a bottomed cylindrical shape whose upper end is open toward the piston body 4 and the bottom portion 71 (see FIG. 2) of the main body portion 31 of the cylinder body 3. The lower rod body 52 is passed through the shaft core portion while forming the lower end portion 31b.

  Therefore, in the oil lock structure including the oil lock piece 6 and the oil lock case 7, this is in the lower oil chamber R2 defined by the piston body 4 in the cylinder body 1 in the double rod type damper. Since the lower oil chamber can be lengthened by shortening the sub-cylinder portion, the stroke that ensures the operation of the oil lock structure does not reduce the expansion / contraction stroke of the damper. Predetermined impact relaxation can be realized while ensuring a damping action based on a predetermined expansion / contraction stroke in the rod type damper.

  And in this oil lock case 7, since the bottom part 71 forms the lower end part 31b of the main-body part 31 in the cylinder body 3, there exists an advantage which enables reduction of the number of parts in this lower end part 31b.

  By the way, in the front fork shown in FIG. 2, the oil lock piece 6 has a main body 61, a holder 62, and a cushion 63, and the main body 61 is screwed to the lower rod body 52 side of the holder 62. Thus, the cushion 63 is press-fitted into the outer periphery of the lower rod body 52 in a state of being serially connected to the holder 62.

  The main body 61 is sandwiched between the holder 62 and a joint 53 (to be described later) while being interposed with a clearance channel on the outer periphery of the holder 62. A notch passage 61 a that is formed and communicates with the gap channel and the outside of the main body 61 is provided.

  Therefore, in the main body 61 in the oil lock piece 6, assuming that there is no flow of hydraulic oil on the outer peripheral side of the main body 61, when the oil lock piece 6 is in the rising state illustrated in FIG. Although communication between the upper and lower sides of the main body 61 is blocked and not shown, when the lower body is in a lowered state, the gap passage is opened to allow communication between the upper and lower sides of the main body 61.

  The oil lock case 7 has a bottom portion 71 and a cylindrical portion 72. As described above, the bottom portion 71 forms the lower end portion 31b of the main body portion 31 of the cylinder body 3, and the cylindrical portion 72 is on the inner side. The oil lock piece 6 is allowed to fit the main body 61 and the cushion 63 is allowed to enter.

  In the oil lock case 7, the cylindrical portion 72 also serves as a connecting member for connecting the main body portion 31 and the sub-cylinder portion 32 in the cylinder body 3, and accordingly, a component in the lower end portion 31 b of the cylinder body 3. The score is reduced.

  In the oil lock structure composed of the oil lock piece 6 and the oil lock case 7 formed as described above, when the oil lock piece 6 is fitted into the oil lock case 7, basically, the body 61 The outer periphery is in sliding contact with the inner periphery of the cylindrical portion 72 in the oil lock case 7, and then the lower end of the cushion 63 in the drawing is in contact with the bottom portion 71 in the oil lock case.

  However, as long as the impact mitigating effect can be obtained, the oil lock piece 6 is provided with the main body 61 by omitting the arrangement of the cushion 63, and the main body 61 has a cylindrical portion 72 in the oil lock case 7. The desired impact relaxation may be realized by fitting to.

  By the way, compared to the case of the oil lock structure, when the cushion 63 is cushioned, there is a fear of the occurrence of repulsive force when the cushion 63 contracts, but from the viewpoint of achieving the original purpose of cushioning, Only the cushion 63 may be provided without the main body 61.

  When the front fork is contracted most and the main body 61 of the oil lock piece 6 is fitted into the cylindrical portion 72 of the oil lock case 7, the main body 61 is maintained in the above-described raised state. A locked state appears and predetermined shock relaxation is achieved.

  Further, when the main fork 61 in the oil lock piece 6 comes out of the cylinder portion 72 in the oil lock case 7 by the front fork changing from the most contracted state to the extending operation, the main body 61 is in the lowered state described above. Thus, the hydraulic oil is allowed to flow into the cylindrical portion 72 and the main body 61 is allowed to escape.

  2, in the rod body 5, the upper rod body 51 and the lower rod body 52 are connected by the connecting member 53, and the connecting member 53 is connected to the oil lock piece 6 as described above. The main body 61 is clamped between the holder 62 and the holder 62.

  The connecting member 53 includes a vertical hole 53a that communicates with an opening core 52 of the lower rod body 52, which will be described later, and a lateral hole that communicates with the outside of the connecting member 53 while communicating with the vertical hole 53a. And a hole 53b.

  Further, in FIG. 2, the rod body 5 constituting the double rod type damper, that is, the lower rod body 52 allows the hydraulic oil from the sub oil chamber R3 to pass to the lower oil chamber R2. It has a check valve 8 that prevents backflow.

  That is, the lower rod body 52 is formed of a pipe body so that the inner side becomes the flow path 52a, and the lower end portion penetrates the lower end portion 31b of the main body portion 31 and the lower end is opened to the sub oil chamber R3. The check valve 6 is provided at the lower end.

  The check valve 8 includes a steel ball 81 and a coil spring 82 as shown in the figure. As shown in the figure, the check valve 8 is energized by the coil spring 82 and is cut off when the steel ball 81 is in the forward state. Although not shown, the steel ball 81 is opened when the steel ball 81 overcomes the spring force of the coil spring 82 and moves backward by hydraulic action.

  Therefore, in the double rod type damper having the check valve 8 in the lower rod body 52, when the hydraulic oil tends to be insufficient in the lower oil chamber R2, the hydraulic oil is replenished from the sub oil chamber R3. The

  From this, in the front fork having the double rod type damper in the shaft core portion, the hydraulic oil is supplied to the reservoir chamber R in a state where the double rod type damper is incorporated in the shaft core portion of the fork main body. By injecting and expanding and contracting the fork main body, that is, by performing a pumping operation, the hydraulic oil injected into the reservoir chamber R can be filled in the double rod type damper.

  Incidentally, the hydraulic oil injected into the reservoir chamber R flows into the lower oil chamber R2 in the cylinder body 3 through the check valve 8 as well as flows into the sub oil chamber R3, and the piston. It also flows into the upper oil chamber R1 via the damping valve 41 of the body 4.

  Until the hydraulic oil flows in, the air occupying the sub oil chamber R3 is accompanied with the check oil 8, the lower oil chamber R2, the pressure side damping valve 42, the upper oil together with the hydraulic oil as the hydraulic oil flows in. It flows out to the reservoir chamber R which is the outside through the chamber R1 and the communication hole 31c.

  In view of the above, in the illustrated front fork, since the lower rod body 52 forming the double rod type damper has the check valve 8, at the end of the completion of the assembly of the front fork, hydraulic oil is introduced into the fork main body. It is possible to fill the main body 31 with the hydraulic oil simply by injecting and expanding and contracting the front fork, that is, by performing a pumping operation. Therefore, troublesome work such as assembling the front fork in the oil tank is not required.

  As described above, the lower rod body 52 in the double rod type damper has the flow path 52a in the axial center portion and the check valve 8 in the lower end portion. Although not shown, sealing plugs may be provided in place of the check valve 8 and shut off from the sub oil chamber R3, or the lower rod body 52 may be formed of a solid body.

  Incidentally, when the lower rod body 52 is a hollow body and the open end is sealed with sealing plugs, the weight of the lower rod body 52 can be reduced and the amount of hydraulic oil flowing into the passage 52a is reduced. This can reduce the overall weight of the front fork.

  In the above description, the case where the front fork is an inverted type in which the vehicle body side tube 1 is the outer tube and the wheel side tube 2 is the inner tube has been taken as an example. Although not shown, it may be an upright type in which the vehicle body side tube 1 is an inner tube and the wheel side tube 2 is an outer tube, and the effects in this case are not different.

It is a figure which shows in principle the front fork which embodies the oil lock structure by one Embodiment of this invention. It is a longitudinal cross-sectional view which partially enlarges and shows the front fork which materialized the oil lock structure by this invention in the double rod type damper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body side tube 1a Cap part 2 Wheel side tube 2a Bottom part 3 Cylinder body 4 Piston body 5 Rod body 6 Oil lock piece 7 Oil lock case 8 Check valve 31 Main body part 31a Upper end part 31b Lower end part 32 Sub cylinder part 51 Upper rod Body 52 Lower rod body 52a Flow path 71 Bottom R2 Lower oil chamber

Claims (4)

A cylinder body that forms a double rod-type damper is disposed on the wheel side tube at the axial center of the fork main body composed of the vehicle body side tube and the wheel side tube, and the upper rod body in the rod body that forms the damper is The lower rod body of the rod body forming the damper is accommodated in the main body portion through the upper end portion of the main body portion of the cylinder body while being suspended from the vehicle body side tube and connected to the piston body in the main body portion. An oil lock is provided in a front fork that extends through the lower end of the main body while protruding from the main body while being connected to the body, and the lower rod body is in a lower oil chamber defined by a piston body in the main body. An oil lock case that holds the piece and fits the oil lock piece to the lower end of the main body that passes through the lower rod body is held. Oil lock structure characterized by comprising a. The oil lock case is formed in a bottomed cylindrical shape whose upper end is open toward the piston body, and the bottom portion penetrates the lower rod body while forming the lower end portion of the main body portion of the cylinder body. Oil lock structure. While the upper end of the upper rod body in the rod body is connected to a cap portion that closes the upper end opening of the vehicle body side tube, the sub cylinder portion is connected to the main body portion at the lower end portion of the main body portion in the cylinder body. The oil lock structure according to claim 1, wherein a lower rod body is inserted through the cylinder portion, and a lower end of the sub cylinder portion is connected to a bottom portion that closes a lower end opening of the wheel side tube. The lower rod body in the rod body has a flow path formed inside, and the lower rod body penetrating the lower end portion of the main body portion in the cylinder body allows the hydraulic oil to flow into the flow path and backflow thereof. The oil lock structure according to claim 1, further comprising a check valve that prevents

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