JP4463489B2 - Steering damper mounting structure for motorcycles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steering damper mounting structure in a motorcycle.
[0002]
[Prior art]
As a mounting structure of a steering damper in a conventional motorcycle, when a vane that divides an oil chamber in a housing into two swings, hydraulic oil flows between the two oil chambers to generate a damping force. A rotary type steering damper having a shaft that supports a vane so as to be swingable with respect to the housing while the base portion is fixedly connected, and a hydraulic control valve that varies a damping force of the rotary type steering damper. It is known that the housing is attached to the steering system and the shaft is attached to the vehicle body frame (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP 2002-302085 A (left column of page 3, FIG. 2, FIG. 3)
[0004]
[Problems to be solved by the invention]
The steering damper mounting structure in the above-described conventional motorcycle has the following problems.
In other words, the rotary type steering damper is mounted above the top bridge, but in reality, the hydraulic control valve provided in the passage connecting the two oil chambers in the housing is driven and controlled for adjusting the damping force. Therefore, it is necessary to provide driving means such as a solenoid. However, while the drive means requires a relatively large arrangement space, the upper position of the top bridge where the rotary type steering damper is arranged is arranged with the fuel tank approaching rearward and an ignition switch forward. Is a very narrow space where various movable parts such as a top bridge and a front fork constituting the steering system are disposed, and such narrow and various movable parts are disposed. There is a problem that it is very difficult to dispose a driving unit that requires a large disposition space at a location.
[0005]
The present invention has been made in view of the above circumstances, and an object of the present invention is to enable automatic placement of drive means that require a relatively large space for driving and controlling a hydraulic control valve for adjusting damping force. An object is to provide a steering damper mounting structure for a motorcycle.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, a steering damper mounting structure in a motorcycle according to claim 1 has two oil chambers (for example, an oil chamber 74a in the embodiment) in a housing (for example, the housing 52 in the embodiment). 74b), the hydraulic oil flows between the two oil chambers when the vane (for example, the vane 75 in the embodiment) swings, generating a damping force, and connecting the base portion of the vane in a fixed state. A rotary steering damper (for example, the steering damper 51 in the embodiment) having a shaft (for example, the shaft 53 in the embodiment) that supports the vane so as to be able to swing, and the rotary steering damper. A hydraulic control valve that varies the damping force (for example, the hydraulic control valve 68 in the embodiment). The housing is attached to either the body frame (for example, the body frame 2 in the embodiment) side or the steering system (for example, the steering system 50 in the embodiment) side, and the shaft is attached to the body frame side or the steering system side. In the mounting structure of a steering damper in a motorcycle in which the housing is disposed above the top bridge (for example, the top bridge 49 in the embodiment), the hydraulic control valve driving means (for example, the linear solenoid 69 in the embodiment) ) Are arranged so as to extend rearward from the housing, and the housing includes a left oil passage (for example, an oil passage 83 in the embodiment) and a right oil passage (for example, respectively) communicating with the left and right oil chambers. For example, the oil passage 84) in the embodiment has the left and right oil chambers. The front side is formed so as to extend further rearward from the rear end of the inner peripheral surface and substantially parallel to each other, and to connect the intermediate portions and the rear end portions of the left oil passage and the right oil passage, respectively. An oil passage (for example, the oil passage 85 in the embodiment) and a rear oil passage (for example, the oil passage 86 in the embodiment) are formed in parallel to each other and orthogonal to the left oil passage and the right oil passage, The intersection of the left oil passage and the front oil passage, the intersection of the left oil passage and the rear oil passage, the intersection of the right oil passage and the front oil passage, the right oil passage and the rear oil passage Check valves (for example, check valves 87 to 90 in the embodiment) are respectively installed at the intersections of the front oil passage and the rear oil passage between the front oil passage and the rear oil passage. ~ side The hydraulic control valve is interposed so as to straddle the oil passage, and a piston that absorbs thermal expansion of hydraulic oil (for example, the free piston 93 in the embodiment) is at a position different from the axial position of the hydraulic control valve, The housing is communicated with the front oil passage through an oil passage extending in the vertical direction (for example, the oil passage 91 in the embodiment), and the piston extends in the front-rear direction above the front oil passage and the rear oil passage. Both the hydraulic control valve and the piston are provided along the front-rear direction in the rear part of the housing, and the front oil passage and the rear oil passage are positioned in the axial direction of the shaft. It said vane and is wrapped, and the piston also, that have the axial position of the shaft is the vane and the lap.
[0007]
In this invention, the housing of the steering damper is disposed above the top bridge, and the drive means of the hydraulic control valve is disposed so as to extend rearward from the housing. Thus, the drive means does not protrude upward or downward from the housing, and the vertical height of the steering damper is pressed to avoid interference between the steering damper and the movable member near the top bridge.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
A steering damper mounting structure in a motorcycle according to the present invention will be described below with reference to the drawings. In the description, descriptions of directions such as front and rear and left and right are based on the vehicle body.
[0009]
As shown in FIG. 1, a motorcycle 1 is provided with a vehicle body frame 2 substantially in the center, and a head pipe 3 provided at the front end of the vehicle body frame 2 has a front fork 5 that supports the front wheels 4 via a steering stem 6. And can be steered. From the head pipe 3 of the vehicle body frame 2, a main frame 7 is provided so as to be divided into left and right and extend obliquely rearward and downward, and then extend downward via a bent portion. A pivot portion 8 is provided at a substantially central front end portion of the portion extending downward from the main frame 7, and the pivot portion 8 supports a rear fork 10 that supports the rear wheel 9 in a swingable manner. Further, a slightly rear portion of the portion supported by the pivot portion 8 of the rear fork 10 is connected to the main frame 7 via the rear cushion 11 and the link portion 12.
[0010]
A seat frame 13 is connected to the rear of the main frame 7. A fuel tank 14 is disposed above the main frame 7, and an engine body 15 of a water-cooled parallel four-cylinder engine is disposed below the main frame 7. An engine hanger 16 extends downward from the front part of the main frame 7, and the engine hanger 16 supports the engine body 15 together with other mounting parts for supporting the engine body provided on the main frame 7.
[0011]
A driver's seat 17 and a passenger's pillion seat 18 are respectively supported by the seat frame 13 behind the fuel tank 14. A driver step 19 is attached to the rear portion of the pivot portion 8 of the vehicle body frame 2, and a passenger step 20 is attached to the lower portion of the seat frame 13. Further, a pair of left and right handles 21, 21 are attached to the upper end portion of the front fork 5 via a top bridge 49.
The front part of the motorcycle 1 is covered with a front cowl 25 and the periphery of the seat frame 13 is covered with a rear cowl 26. A retractable side stand 27 is disposed at the lower left side of the body frame 2, and the side stand 27 supports the vehicle body of the motorcycle 1 in an upright state inclined to the left side.
[0012]
A brake caliper 28 is attached to the lower end of the front fork 5, and a brake rotor 29 corresponding to the brake caliper 28 is attached to the front wheel 4 to constitute a front brake device 30. A front fender 31 that covers the upper portion of the front wheel 4 is attached to the lower end of the front fork 5.
A rear sprocket 32 is attached to the left side of the rear wheel 9 so as to rotate integrally with the rear wheel 9, and a drive chain 34 is connected to the rear sprocket 32 and a drive sprocket 33 disposed on the left side of the rear portion of the engine body 15. The driving force of the engine body 15 is transmitted to the rear wheel 9 by being hung around. A front rear fender 35 that covers the upper front side of the rear wheel 9 is attached to the upper part of the rear fork 10, and a rear fender 36 that covers the upper rear side of the rear wheel 9 is attached to the lower part of the rear cowl 26. The rear frame 10 is provided with a rear brake device having the same configuration as the front brake device 30 of the front wheel 4.
[0013]
The cylinder body 40 of the engine body 15 is disposed on the crankcase 41 in a slightly tilted state. A throttle body 42 corresponding to each cylinder is connected to a rear portion of the cylinder body 40, and each throttle body 42 is connected to an air cleaner case 43 disposed between the main frame 7 and the fuel tank 14. An exhaust pipe 44 corresponding to each cylinder is connected to the front portion of the cylinder body 40. The exhaust pipe 44 extends forward from the front wall 45 of the cylinder body 40 and then curves downward, and extends to the rear of the engine body 15 through the front and lower sides of the crankcase 41.
[0014]
The steering stem 6, the top bridge 49 disposed parallel to the bottom bridge above the bottom bridge of the steering stem 6, the handle 21, and the like constitute a steering system 50 for steering the front wheels 4. A steering damper 51 is interposed between the steering system 50 and the vehicle body frame 2 (see FIGS. 2 and 3).
[0015]
The steering damper 51 is for reducing the deflection of the handle 21 due to kickback or the like during a disturbance, and there are usually two types, a rod type and a rotary type. Here, the rotary type is excellent in terms of compactness. The steering damper 51 is used.
[0016]
As shown in FIG. 2, the steering damper 51 includes a housing 52 and a shaft 53 that protrudes outward through the upper and lower surfaces of the housing 52. The housing 52 is attached to a mounting portion 3 a provided integrally with the head pipe 3 and extending rearward via a bracket 54. On the other hand, the shaft 53 is attached so that the lower end portion thereof is spline-fitted to the upper end portion of the steering stem 6, for example, and rotates integrally with the steering stem 6.
[0017]
The housing 52 of the steering damper 51 is attached so as to be positioned above the top bridge 49 via the bracket 54 and so as to extend further rearward while partially overlapping with the top bridge 49 in plan view. A linear solenoid 69, which is an example of a drive unit that drives and controls the hydraulic control valve 68, is disposed on the rear end surface of the housing 52 so as to extend rearward from the housing 52. Has been.
[0018]
A concave portion 14 a is formed in the front portion of the fuel tank 14 in order to avoid interference with the steering damper 51 and the bracket 54. In FIG. 2, reference numeral 70 denotes an ignition switch arranged in front of the head pipe.
[0019]
As shown in FIGS. 4 to 7, the housing 52 of the steering damper 51 includes a body 71 and a cap 72. A fan-shaped recess 73 is formed on the upper surface of the body 71, and the recess 73 is covered with a cap 72 to form an oil chamber 74. The oil chamber 74 is divided into two oil chambers 74 a and 74 b by the vane 75. As shown in FIG. 5, the base portion 75a of the vane 75 is formed in a cylindrical shape, and the shaft 53 is fixed to the cylindrical portion so as to rotate integrally with the vane 75 through fixing means such as spline fitting. Connected in state. The vane 75 is supported by the shaft 53 so as to be swingable with respect to the housing 52.
[0020]
Grooves 75b are formed in the upper end portion, the lower end portion, and the rear end portion of the vane 75 facing the inner peripheral surface of the oil chamber 74 so as to be continuous with them, and these grooves 75b are matched to the shape of the groove 75b. A sealing member 76 formed in a U-shape is fitted. Here, the groove 75b and the seal member 76 do not reach the shaft 53 but are formed or fitted to the front thereof.
[0021]
Sealing washers 77a and 77b are fitted to the outer periphery of the shaft 53 so as to contact the upper and lower surface portions of the base portion 75a of the vane 75, and part of the outer periphery of the upper and lower sealing washers 77a and 77b. Is in contact with the seal member 76. In other words, the two oil chambers 74a and 74b defined in the housing 52 are held in a liquid-tight state by the seal member 76 and the seal washers 77a and 77b, and are also held in a liquid-tight state with respect to the shaft 53. Is done.
[0022]
A circlip 78, a washer 79, and a seal member 80 are fitted into the outer peripheral portion of the shaft 53 that penetrates the cap 72 in order from the upper side. A bush 81 and a seal member 82 are fitted into the outer peripheral portion of the shaft passing through the body 71 in order from the upper side.
[0023]
As shown in FIGS. 5 and 7, the body 71 of the housing 52 has oil passages 83 and 84 communicating with the left and right oil chambers 74a and 74b, respectively, from the rear end of the inner peripheral surface of these oil chambers 74a and 74b. Further, they are formed so as to extend rearward and substantially parallel to each other. The oil passages 85 and 86 are parallel to each other and orthogonal to the oil passages 83 and 84 so as to connect the intermediate portions of the oil passages 83 and 84 and the rear ends of the oil passages 83 and 84, respectively. Is formed. Check valves are provided at the intersection of the oil passage 83 and the oil passage 85, the intersection of the oil passage 84 and the oil passage 85, the intersection of the oil passage 83 and the oil passage 86, and the intersection of the oil passage 84 and the oil passage 86, respectively. 87, 88, 89, and 90 are interposed, respectively. A hydraulic control valve 68 is interposed between the oil passage 85 and the oil passage 86 so as to straddle the oil passages.
[0024]
Here, the check valves 87, 88, 89, 90 have the same configuration. The check valve 87 will be described as an example. The valve body 87a is provided with a valve seat 87b and accommodates a ball 87c. The ball 87c is urged with an appropriate pressing force by a spring 87d so as to contact the valve seat 87b. Has been. According to the check valve 87, although the flow of the fluid in the direction separating the ball 87c from the valve seat 87b is permitted against the urging force of the spring 87d, the fluid in the direction flowing in from the side of the check valve 87 is allowed. The flow is blocked. Here, the check valve 87 allows the flow of hydraulic oil from the oil passage 85 to the oil passage 83 side, but blocks the flow of hydraulic oil in the reverse direction. The check valve 88 allows the flow of hydraulic oil from the oil passage 85 to the oil passage 84 side, but blocks the flow of hydraulic oil in the reverse direction. The check valve 89 allows the flow of hydraulic oil from the oil passage 83 to the oil passage 86 side, but blocks the flow of hydraulic oil in the reverse direction. Further, the check valve 90 allows the flow of hydraulic oil from the oil passage 84 to the oil passage 86 side, but blocks the flow of hydraulic oil in the reverse direction.
[0025]
As shown in FIG. 7, the hydraulic control valve 68 changes the damping force of the steering damper 51. The hydraulic control valve 68 is provided with a valve seat 68b on a valve body 68a and a poppet 68c so as to face the valve seat 68b. The poppet 68c is biased with an appropriate pressing force by a spring 68d interposed between the bottom spring seat of the poppet 68c and the bottom surface of the valve hole so as to abut against the valve seat 68b. The poppet 68 is formed with a through hole 68e laterally so that hydraulic oil flows into the poppet 68. The front end of the push rod 68f is in contact with the center of the rear end surface of the poppet 68c facing the valve seat 68b, and the rear end of the push rod 68f is connected to the linear solenoid 69. Then, the poppet 68c is pressed and adjusted so that the head of the poppet 68c is separated from the valve seat 68c against the biasing force of the spring 68d by an excitation operation of the linear solenoid 69 or the like.
[0026]
In other words, according to the hydraulic control valve 68, the poppet 68c has the pressure difference between the left and right oil chambers 74a and 74b in the housing 52 communicating with the space between the head and the bottom, the biasing force of the spring 68d, and the push rod 68f. The position is determined by the exciting force of the linear solenoid 69, and the resultant force of the poppet pressing force based on the differential pressure between the left and right oil chambers 74a and 74b and the exciting force of the linear solenoid 69 is weaker than the biasing force of the spring 68d. The poppet 68c contacts the valve seat 68b and the hydraulic control valve 68 is closed, and the resultant force of the poppet pressing force based on the differential pressure between the left and right oil chambers 74a and 74b and the exciting force of the linear solenoid 69 is a spring. When the urging force of 68d is exceeded, the poppet 68c is separated from the valve seat 68b, and the hydraulic control valve 68 is opened. . A predetermined damping force is obtained when the hydraulic oil passes through a gap between the valve seat 68b and the poppet 68c of the hydraulic control valve 68.
The linear solenoid 69 is controlled by a control unit (not shown) so that a smaller excitation force is exerted when the vehicle speed or the vehicle body acceleration is increased.
[0027]
As shown in FIGS. 5 and 7, the oil passage 85 is communicated with the free piston 93 via an oil passage 91 extending in the vertical direction in the housing. The free piston 93 includes a cylinder 93a formed integrally with the body 71, a piston 93c that defines a storage portion 93b for storing hydraulic oil in a front portion of the cylinder 93a, and the piston 93c toward the storage portion 93b. A spring 93d for biasing is provided. In this free piston 93, when the hydraulic oil filled in the closed space composed of the oil chambers 74a, 74b and the oil passages 83, 84, etc. communicating between the oil chambers expands or contracts due to a temperature change. As the piston 93c moves, the capacity of the storage portion 93b changes, and absorbs thermal expansion and the like of the hydraulic oil.
[0028]
Next, the operation of the steering damper mounting structure in the motorcycle having the above-described configuration will be described.
When the steering wheel 21 is turned to the left side during traveling, for example, the top bridge 49 and the steering stem 6 rotate in the same direction integrally with the steering wheel 21, and the movement of the steering stem 6 is transmitted to the shaft 53. The shaft 53 also rotates in the counterclockwise direction of the clock hand in FIG. 7, and the vane 75 rotates in the same direction ((A) in FIG. 7). Along with this, the pressure of the hydraulic oil filled in the oil chamber 74b becomes narrower and the hydraulic oil in the oil chamber 74b increases, and the hydraulic oil in the oil chamber 74b is separated from the vane 75 and the inner peripheral surface defining the oil chamber 74. It moves directly to the oil chamber 74a on the other side through a gap between them. Thus, although some hydraulic oil moves directly between the oil chambers 74a and 74b, when the pressure of the hydraulic oil in the oil chamber 74b that is still narrow becomes high, this hydraulic oil is indicated by a solid line arrow in FIG. As shown, the oil passage 84 and the check valve 90 are passed to the oil passage 86 and from there to the pressure control valve 68.
[0029]
In the pressure control valve 68, the poppet 68c is normally in contact with the valve seat 68b by the urging force of the spring 68d and is in a closed state. For example, the poppet 68c remains closed even when a slight hydraulic pressure is applied from the oil chamber 74b side. If the resultant force of the pressing force based on the differential pressure between the left and right oil chambers 74a and 74b and the exciting force of the linear solenoid 69 exceeds the biasing force of the spring 68d, the poppet 68c is separated from the valve seat 68b. Then, the hydraulic control valve 68 is opened. At this time, the hydraulic oil in the oil passage 86 passes through the gap between the valve seat 68b and the poppet 68c of the hydraulic control valve 68 and reaches the oil passage 85, from which the check valve 87 and the oil passage 83 are further passed. It leads to the oil chamber 74a on the left side (see solid line arrow in FIG. 7). Thus, the resistance when the hydraulic oil passes through the pressure control valve 68 or the like generates a damping force and acts on the handle 21. That is, it becomes a resistance force when the handle 21 is cut, and acts as a resistance force against the instantaneous rotational force acting on the handle 21.
[0030]
The above description is for turning the handle 21 to the left, but the same is true for turning the handle 21 to the right. In addition, the flow of the hydraulic oil in this case is shown by a broken line arrow in FIG.
[0031]
The linear solenoid 69 is controlled by the vehicle speed and the vehicle body acceleration. For example, the linear solenoid 69 is controlled by a control unit (not shown) so that the excitation force is weakened when the vehicle speed increases or the vehicle body acceleration increases. Accordingly, at this time, the valve opening timing of the hydraulic control valve 68 is delayed, and the valve opening is reduced by the amount that the excitation force is weakened even after the valve is opened, and a larger damping force is exhibited. That is, the higher the vehicle speed and the higher the acceleration, the higher the damping force.
[0032]
Therefore, when traveling at low speed or low acceleration, the handleability can be emphasized and the handle 21 can be turned with a relatively light force. However, when traveling at high speed or high acceleration, a high damping force can be applied when turning the handle 21. As a result, the occurrence of the kickback phenomenon can be reduced.
[0033]
In the control of the steering damper 51, when the temperature of the hydraulic oil filled in the oil chamber 74 and the oil passages 83, 84,... When the piston 93c of the free piston 93 moves in the cylinder 93a, the capacity change of the hydraulic oil is absorbed.
[0034]
In the above-described embodiment, the housing 52 of the steering damper 51 is disposed above the top bridge 49, and the linear solenoid 69 that constitutes the drive means of the hydraulic control valve 68 is extended rearward from the housing 52. Since the linear solenoid 69 does not protrude upward or downward from the housing 52, the height of the steering damper 51 can be suppressed, so that the steering damper 51 does not protrude upward from the steering system near the top bridge 49. Can be placed.
[0035]
In the steering damper 51, since the oil passages 83 are formed in one stage in the housing 52, the height of the housing 52 can be reduced compared with the case where the oil passages are formed in two stages, and the linear solenoid Combined with the configuration in which 69 is arranged to extend rearward from the housing 52, the height of the steering damper 51 can be further reduced.
[0036]
The above embodiment is merely an example of the present invention, and the design can be changed as appropriate without departing from the gist of the invention as necessary.
For example, in the above-described embodiment, the housing 52 of the steering damper 51 is attached to the vehicle body frame 2 side, and the shaft 53 is attached to the steering system 50. Conversely, the housing 52 of the steering damper 51 is attached to the steering system. 50, the shaft 53 may be attached to the body frame 2 side.
[0037]
In the above-described embodiment, the housing 52 of the steering damper 51 is attached to the head pipe 3. However, the housing 52 may be attached directly to the rear extension portion of the vehicle body frame 2 extending rearward from the head pipe 3 or via a stay. Good.
In the above-described embodiment, the linear solenoid 69 is used as the drive means for the hydraulic control valve 68. However, the present invention is not limited to this, and a drive means using hydraulic pressure or the like may be used.
[0038]
【The invention's effect】
As described above in detail, according to the steering damper mounting structure in the motorcycle of the present invention, the housing of the steering damper is disposed above the top bridge, and the drive means of the hydraulic control valve extends rearward from the housing. Even if the drive means for driving the hydraulic control valve is relatively large, the drive means is arranged by pressing the height of the steering damper without the drive means protruding upward or downward from the housing. can do. Further, the drive means does not protrude downward or upward from the housing, and therefore it is possible to avoid the drive means from interfering with a movable member attached to a handle or the like near the top bridge.
[Brief description of the drawings]
FIG. 1 is a side view of a motorcycle showing an embodiment of the present invention.
FIG. 2 is a side view, partly in section, showing a steering damper mounting structure in the same motorcycle.
FIG. 3 is a plan view showing a steering damper mounting structure in the same motorcycle.
FIG. 4 is a plan view of a steering damper.
FIG. 5 is a longitudinal sectional view of a steering damper.
6 is a view taken in the direction of arrow Z in FIG.
FIG. 7 is a cross-sectional view of a part of the housing of the steering damper.
[Explanation of symbols]
1 ... motorcycle, 2 ... body frame,
3 ... head pipe, 6 ... steering stem,
14 ... Fuel tank, 21 ... Handle,
49 ... Top bridge, 50 ... Steering system 51 ... Steering damper, 52 ... Housing,
54 ... Bracket, 68 ... Hydraulic control valve,
69 ... Linear solenoid (drive means), 74 (74a, 74b) ... Oil chamber,
75 ... Vane, 93 ... Free piston.

Claims (1)

When the vane which divides the oil chamber in the housing into two is oscillated, the hydraulic oil flows between the two oil chambers to generate a damping force, and the housing is connected to the base of the vane while being fixedly connected. A rotary steering damper having a shaft for swingably supporting the vane, and a hydraulic control valve for changing the damping force of the rotary steering damper, the housing being mounted on the vehicle body frame side And a steering damper mounting structure in a motorcycle in which the shaft is attached to the other of the vehicle body frame side and the steering system side, and the housing is disposed above the top bridge.
The drive means of the hydraulic control valve is arranged to extend rearward from the housing,
In the housing, a left oil passage and a right oil passage communicating with the left and right oil chambers are formed so as to extend further rearward from the rear ends of the inner peripheral surfaces of the left and right oil chambers and to be substantially parallel to each other. In addition, the front oil passage and the rear oil passage are parallel to each other and are connected to the left oil passage and the right oil passage so that the intermediate portions and the rear end portions of the left oil passage and the right oil passage are connected to each other. It is formed to be orthogonal,
The intersection of the left oil passage and the front oil passage, the intersection of the left oil passage and the rear oil passage, the intersection of the right oil passage and the front oil passage, the right oil passage and the rear oil passage Check valves are installed at each intersection of
The hydraulic control valve is interposed between the front oil passage and the rear oil passage so as to straddle the front oil passage and the rear oil passage,
A piston that absorbs thermal expansion of hydraulic oil is at a position different from the axial position of the hydraulic control valve, and is communicated with the front oil passage through an oil passage that extends in the vertical direction in the housing.
The piston is disposed along the front-rear direction above the front oil passage and the rear oil passage ,
Both the hydraulic control valve and the piston are provided along the front-rear direction at the rear of the housing;
The front oil passage and the rear oil passage, the axial position of the shaft is the vane and the lap, and the piston also a feature that you have the axial position of the shaft is the vane and a lap Structure of a steering damper in a motorcycle.

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