Shock absorber, vehicle, and snowmobile

A shock absorber includes a cylinder and a piston. The piston is configured to partition an internal space of the cylinder into two oil chambers and is capable of sliding in an axial direction of the cylinder. The piston having formed therethrough a communication path configured to bring the two oil chambers into communication with each other. The shock absorber also includes a first rod and a second rod. The first rod extends in a first direction of the axial direction with respect to the piston. The second rod has a diameter larger than a diameter of the first rod, and extends in a second direction of the axial direction, which is opposite to the first direction, with respect to the piston. The shock absorber further includes a rod mounting member, which is provided on the first rod, and a cylinder mounting member, which is provided on the cylinder and arranged as offset from an axis of the cylinder.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese application JP2016-194461 filed on Sep. 30, 2016, the content of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

Description of the Related Art

In general, in a shock absorber for a vehicle, one rod coupled to a piston provided inside a cylinder extends externally from one end portion of the cylinder. Oil filling the cylinder is pressurized by a high-pressure gas, a spring, or the like. With this structure, a force is exerted on the rod in a direction in which the rod projects from the cylinder by a pressure received by the piston from the oil. Specifically, the force generated by a hydraulic pressure is exerted on the shock absorber in an extension direction.

The shock absorber as described above, in which the force generated by the hydraulic pressure is exerted in the extension direction, may not sufficiently absorb a shock received from a ground surface, resulting in a fear of adversely affecting riding comfort of a vehicle. Further, timing of a load shift to an outer wheel or ski is likely to be advanced at cornering, also resulting in the fear of adversely affecting the riding comfort of the vehicle.

To cope with the adverse effect described above, the following is disclosed in Japanese Patent Application Laid-open No. 2010-96347. Specifically, in the shock absorber including a main piston rod provided on one side of the piston and a sub-piston rod provided on another side of the piston, a diameter of the sub-piston rod is set larger than a diameter of the main piston rod to be coupled externally. With this structure, a force is exerted on the main piston rod in a direction in which the main piston rod is accommodated into the cylinder. Specifically, the force generated by the hydraulic pressure is exerted on the shock absorber in a contraction direction.

The shock absorber in which the force generated by the hydraulic pressure is exerted in the contraction direction as described above can solve the problem of the above-mentioned shock absorber in which the force generated by the hydraulic pressure is exerted in the extension direction to improve the riding comfort of the vehicle.

SUMMARY OF THE INVENTION

In the shock absorber, in which the force generated by the hydraulic pressure is exerted in the contraction direction, a movable range is required for the two rods. Therefore, the shock absorber cannot be prevented from being increased in length and size, and has a problem in ease of layout. In the shock absorber disclosed in Japanese Patent Application Laid-open No. 2010-96347, a cylinder tube is formed about twice as long as an interval between a first rod guide and a second rod guide so as to accommodate the sub-piston rod extending from the second rod guide.

In particular, the shock absorber to be applied to a vehicle for running on an irregular ground, such as a recreational off-highway vehicle (ROV) or a snowmobile, is required to ensure an ability to absorb the shock. Thus, it is difficult to reduce a rod length and a cylinder size.

The present application has been made to solve the problems described above, and has an object to provide a shock absorber, a vehicle, and a snowmobile, which are capable of improving ease of layout of the shock absorber in which a force generated by a hydraulic pressure is exerted in a contraction direction.

According to one embodiment of the present application, a shock absorber includes a cylinder and a piston. The piston is configured to partition an internal space of the cylinder into two oil chambers and is capable of sliding in an axial direction of the cylinder. The piston having formed therethrough a communication path configured to bring the two oil chambers into communication with each other. The shock absorber includes a first rod, a first rod guide, a second rod, and a second rod guide. The first rod extends in a first direction of the axial direction with respect to the piston. The first rod passes through the first rod guide and the first rod guide is provided on the cylinder. The second rod has a diameter larger than a diameter of the first rod. The second rod extends in a second direction of the axial direction, which is opposite to the first direction, with respect to the piston. The second rod passes through the second rod guide and the second rod guide is provided on the cylinder. The shock absorber further includes a pressurizing mechanism, a rod mounting member, a cylinder mounting member, and a spring. The pressurizing mechanism is configured to pressurize oil filling the internal space of the cylinder. The rod mounting member is provided on the first rod outside of the cylinder. The cylinder mounting member is provided on the cylinder outside of the cylinder. The spring expands and contracts in accordance with relative movement between the rod mounting member and the cylinder mounting member. The cylinder mounting member is offset from an axis of the cylinder.

Further, according to another embodiment of the present application, a vehicle includes the shock absorber.

According to the shock absorber described above, the cylinder mounting member is offset from the axis of the cylinder. Hence, a distance between the rod mounting member and the cylinder mounting member can be reduced while ensuring the movable range of the second rod. In this manner, the ease of layout of the shock absorber can be improved.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described by referencing the appended figures representing embodiments.

FIG. 1is a side view of a snowmobile1according to an embodiment of the present application, andFIG. 2is a front view of the snowmobile1. InFIG. 2, illustration of a front cover9(seeFIG. 1) configured to cover a front part of the snowmobile1is omitted. In the following description, a direction indicated by the arrow Y1is referred to as “forward direction”. A direction indicated by the arrow Y2is referred to as “rearward direction”. A side indicated by the arrow Y1is referred to as “front side” and a side indicated by the arrow Y2is referred to as “rear side” inFIG. 1andFIG. 2. Similarly, a direction indicated by the arrow Z1is referred to as “upward direction”. A direction indicated by the arrow Z2is referred to as “downward direction”. A side indicated by the arrow Z1is referred to as “upper side” and a side indicated by the arrow Z2is referred to as “lower side”. A direction indicated by the arrow X1is referred to as “right-hand direction”. A direction indicated by the arrow X2is referred to as “left-hand direction”. A side indicated by the arrow X1is referred to as “right side” and a side indicated by the arrow X2is referred to as “left side”.

As illustrated inFIG. 2, the snowmobile1includes a right ski41R arranged on the right of a vehicle body frame30and a left ski41L arranged on the left of the vehicle body frame30as grounded portions. The right ski41R is supported by a lower arm42R and an upper arm43R. Similarly, the left ski41L is supported by a lower arm42L and an upper arm43L. The right lower arm42R and the right upper arm43R extend in the right-hand direction from base portions thereof coupled to the vehicle body frame30and are coupled to a knuckle44having a lower end coupled to the right ski41R. The left lower arm42L and the left upper arm43L extend in the left-hand direction from base portions thereof coupled to the vehicle body frame30and are coupled to another knuckle44having a lower end coupled to the left ski41L. The base portions of the arms42R,43R,42L, and43L are coupled to the vehicle body frame30so as to be rotatable. As a result, the skis41R and41L are vertically movable relative to the vehicle body frame30.

The snowmobile1includes shock absorbers50R and50L (hereinafter also collectively referred to as “shock absorbers50”) according to the embodiment. The right shock absorber50R includes a right damper51R and a right spring52R. The left shock absorber50L includes a left damper51L and a left spring52L. One end of each of the dampers51R and51L (hereinafter also collectively referred to as “dampers51”) is coupled to a corresponding one of brackets301provided on the vehicle body frame30, whereas another end of each of the dampers51R and51L is coupled to a corresponding one of brackets421provided on the lower arms42R and42L, respectively. The springs52R and52L (hereinafter also collectively referred to as “springs52”) are, for example, coil springs, and exhibit spring forces in accordance with extension and contraction of the dampers51R and51L. A detailed configuration of each of the shock absorbers50R and50L is described later.

As illustrated inFIG. 1, the snowmobile1includes an engine11and a transmission12as a drive system. The engine11includes a crank case11dconfigured to accommodate a crankshaft (not shown) therein, a cylinder block11bmounted to the crank case11d, and a cylinder head11cmounted to the cylinder block11b. A cylinder is formed inside the cylinder block11b. An intake passage and an exhaust passage being in communication with a combustion chamber of the cylinder are formed inside the cylinder head11c. The crank case11dis positioned on the rear side of the arms42R and43R configured to support the ski41R and the arms42L and43L configured to support the ski41L on a side view of a vehicle body. The cylinder block11band the cylinder head11care arranged so that an axis of the cylinder is inclined rearward with respect to the engine11. A posture of the engine11is not limited to an illustrated example.

The transmission12is, for example, a continuously variable transmission, and includes a drive pulley12aconfigured to receive a torque from the crankshaft and a driven pulley12bconfigured to receive the torque from the drive pulley12a. A belt configured to transfer the torque of the drive pulley12ato the driven pulley12bis looped around the drive pulley12aand the driven pulley12b. The drive pulley12ais provided on, for example, an end portion of the crankshaft. The driven pulley12bis provided on, for example, a secondary shaft (not shown) which is positioned on the rear side of the crankshaft and at a higher position than a position of the crankshaft. The transmission12is not necessarily required to be the continuously variable transmission, and may be, for example, a gear type transmission including a gear having a plurality of gear positions.

The snowmobile1includes a track belt drive shaft14provided with a sprocket configured to mesh with a track belt16. The track belt drive shaft14is coupled to the secondary shaft via a belt, a chain, or the like to receive the torque of the engine11through the transmission12. Guide wheels15a,15b, and15c, a slide rail17, a link structure18, and a shock absorber19are arranged inside the track belt16. The guide wheels15a,15b, and15c, and the slide rail17are configured to guide the track belt16. The link structure18and the shock absorber19are provided between the guide wheel15csupported on the vehicle body frame30and the slide rail17. The slide rail17configured to guide the track belt16is vertically movable relative to the vehicle body frame30through the link structure18. The shock absorber19is arranged between the vehicle body frame30and the track belt16.

The snowmobile1has a seat8for a driver to sit in. The seat8is arranged above the track belt16. In front of the seat8, a steering handle21configured to steer the skis41R and41L is arranged. The steering handle21is mounted to a top of a steering column22. The steering column22extends downward and obliquely to the front side from a central portion of the steering handle21. The steering handle21is coupled to the skis41R and41L through intermediation of the steering column22and tie rods45(seeFIG. 2).

The shock absorber50according to the embodiment is now described. The shock absorber50is a shock absorber in which a force generated by a hydraulic pressure is exerted in a contraction direction, as described later.FIG. 3is a front view of the shock absorber50, andFIG. 4is a side view of the shock absorber50.FIG. 5andFIG. 6are sectional views of the shock absorber50when the shock absorber50is cut along the line V-V ofFIG. 4through an axis CA of the cylinder60.FIG. 5is the sectional view for illustrating a state in which the shock absorber50is most extended, whereasFIG. 6is the sectional view for illustrating a state in which the shock absorber50is most contracted.

In the following description, a direction indicated by the arrow Z3and a direction indicated by the arrow Z4which are parallel to the axis CA of the cylinder60are referred to as “upward direction” and “downward direction”, respectively. A side indicated by the arrow Z3and a side indicated by the arrow Z4are referred to as “upper side” and “lower side”, respectively. The upward direction, the downward direction, the upper side, and the lower side for the shock absorber50correspond to the upward direction, the downward direction, the upper side, and the lower side for the snowmobile1, respectively.

The damper51of the shock absorber50includes a cylinder60having a cylindrical shape, a piston65, a first rod (main rod)61, and a second rod (sub-rod)62. The cylinder60is filled with oil. The piston65is slidable in a vertical direction inside the cylinder60. The first rod61extends downward with respect to the piston65. The second rod62extends upward with respect to the piston65. A rod mounting member81mounted to one of two targets of damping is provided on a lower end portion of the first rod61, whereas a cylinder mounting member95mounted to another of the two targets is provided on an upper end portion of the cylinder60. The spring52is expanded and contracted in accordance with relative movement between the rod mounting member81and the cylinder mounting member95.

The cylinder60includes a cylinder tube64having a cylindrical shape, a first rod guide70, and a second rod guide75. The first rod guide70is provided on a lower end portion of the cylinder tube64and is configured to allow the first rod61to pass therethrough. The second rod guide75is provided on an upper end portion of the cylinder tube64and is configured to allow the second rod62to pass therethrough. The first rod guide70is fitted into the lower end portion of the cylinder tube64. The first rod guide70includes a guide main body71having an approximately hollow cylindrical shape, a lid body72, an oil seal73, and a rubber member74. The lid body72is positioned below the guide main body71. The oil seal73is provided between the first rod61and the guide main body71. The rubber member74is mounted to a top of the guide main body71. The lid body72is configured to close a lower end opening of the cylinder tube64and is fixed to the guide main body71with a screw. The rubber member74comes into abutment against a stopper66described later when the shock absorber50is most extended (seeFIG. 5).

The second rod guide75is fitted into a cap member90mounted to the upper end portion of the cylinder tube64and is arranged to close an upper end opening of the cylinder tube64. The second rod guide75includes a guide main body76having an approximately hollow cylindrical shape, a plate member77having an annular shape, an oil seal78, and a plate member79having an annular shape. The plate member77is positioned above the guide main body76. The oil seal78is provided between the second rod62and the guide main body76. The plate member79is mounted to a lower portion of the guide main body76. The plate member79comes into abutment against a stopper67described later when the shock absorber50is most contracted (seeFIG. 6). An outer diameter of the lower portion of the guide main body76is smaller than a diameter of the upper end opening of the cylinder tube64. A gap759is formed between the upper end of the cylinder tube64and the second rod guide75. A space inside the cylinder60is brought into communication with a pressurizing mechanism100described later through the gap759.

The piston65is slidable in the vertical direction being an axial direction of the cylinder60between the first rod guide70and the second rod guide75inside the cylinder tube64. The piston65partitions a space inside the cylinder tube64between the first rod guide70and the second rod guide75, which is filled with oil, into a first oil chamber60A and a second oil chamber60B. The first oil chamber60A is a space between the piston65and the first rod guide70, whereas the second oil chamber60B is a space between the piston65and the second rod guide75.

Further, communication paths65aconfigured to bring the first oil chamber60A and the second oil chamber60B into communication with each other are formed in the piston65. When the shock absorber50is extended, specifically, when the piston65is moved downward, the oil is moved from the first oil chamber60A into the second oil chamber60B through the communication paths65a. On the other hand, when the shock absorber50is contracted, specifically, when the piston65is moved upward, the oil is moved from the second oil chamber60B into the first oil chamber60A through the communication paths65a. By the movement of the oil through the communication paths65aas described above, a damping force is generated.

The first rod61extends below the piston65, whereas the second rod62having a larger diameter than that of the first rod61extends above the piston65. The first rod61extends downward from the piston65and passes through the first oil chamber60A to slidably pass through the first rod guide70to project externally from the cylinder60. A portion of the first rod61, which projects externally from the cylinder60, becomes longer as the piston65is moved downward, whereas a portion of the first rod61, which is accommodated in the cylinder60, becomes longer as the piston65is moved upward.

Meanwhile, the second rod62extends upward from the piston65and passes through the second oil chamber60B to slidably pass through the second rod guide75. When the piston65is positioned above a lowermost position (seeFIG. 5), the second rod62projects from the second rod guide75to outside of the cylinder60. A portion of the second rod62, which is accommodated in the cylinder60, becomes longer as the piston65is moved downward, whereas a portion of the second rod62, which projects externally from the cylinder60, becomes longer as the piston65is moved upward. The cap member90has a cylinder portion93having a cylindrical shape. The cylinder portion93is formed above a main body portion91which is configured to accommodate the second rod guide75therein and is mounted to the upper end portion of the cylinder tube64, and has a through hole93apassing in the vertical direction. The second rod62passes through the through hole93aof the cylinder portion93to project externally from the cylinder60and also from the cap member90.

The stopper66having an annular plate shape is provided at a position slightly down away from the piston65. The stopper66comes into abutment against the rubber member74of the first rod guide70when the shock absorber50is most extended, specifically, when the piston65is positioned at the lowermost position (seeFIG. 5). Further, the stopper67having an annular plate shape is also provided at a position slightly up away from the piston65. The stopper67comes into abutment with the plate member79of the second rod guide75when the shock absorber50is most contracted, specifically, when the piston65is positioned at an uppermost position (seeFIG. 6).

More specifically, an upper end portion of the first rod61passes through the piston65to be located above the piston65so as to be forced into a lower end portion of the second rod62having a larger diameter than that of the first rod61. The stopper66is fitted over an outer periphery of the first rod61to be opposed to a lower surface of the piston65.

Meanwhile, the stopper67is fitted over an outer periphery of the first rod61to be opposed to an upper surface of the piston65to come into abutment against a lower surface of the second rod62. Further, a sub-communication path61aconfigured to bring the communication paths65aof the piston65and the first oil chamber60A into communication with each other is formed in the first rod61. A needle valve612configured to adjust an opening degree of the sub-communication path61ato increase or decrease the damping force is accommodated inside the first rod61.

The damper51of the shock absorber50further includes the pressurizing mechanism100configured to pressurize the oil filling a space inside the cylinder60. The pressurizing mechanism100includes a cylinder101having a cylindrical shape and a piston102. The cylinder101has the vertical direction as an axial direction. The piston102is slidable in the vertical direction inside the cylinder101. The piston102partitions a space inside the cylinder101into a gas chamber100A and an oil chamber100B. The gas chamber100A is filled with a high-pressure gas, whereas the oil chamber100B is in communication with the cylinder60and is filled with the oil. The pressurizing mechanism100is mounted to the cap member90mounted to the upper end portion of the cylinder tube64.

More specifically, the cap member90includes a pressurizing-mechanism mounting portion92extending radially from the main body portion91mounted to the upper end portion of the cylinder tube64. The pressurizing mechanism100is coupled to a lower surface of the pressurizing-mechanism mounting portion92. A communication path92aconfigured to bring the cylinder60of the damper51and the cylinder101of the pressurizing mechanism100into communication with each other is formed in the pressurizing-mechanism mounting portion92. The communication path92ais brought into communication with the space inside the cylinder60through the gap759formed between the upper end of the cylinder tube64and the second rod guide75. A pressure applied to the oil in the oil chamber100B from the piston102through the high-pressure gas enclosed within the gas chamber100A of the cylinder101is transferred to the oil inside the cylinder60of the damper51through the communication path92aformed in the pressurizing-mechanism mounting portion92.

In the shock absorber50of this embodiment, the second rod62positioned on the upper side is formed to have a larger diameter than that of the first rod61positioned on the lower side, as described above. In this case, the force generated by the hydraulic pressure is exerted upward at a boundary portion between the first rod61and the second rod62. In this embodiment, the stopper67is arranged at the boundary between the first rod61and the second rod62. An area of an upper pressure-receiving surface of the stopper67is smaller than an area of a lower pressure-receiving surface of the stopper67. Hence, the force generated by the hydraulic pressure is exerted upward on the stopper67. As a result, the force generated by the hydraulic pressure is exerted upward, specifically, in a direction in which the first rod61is accommodated into the cylinder60even when the first rod61is coupled to the stopper67and the like. In this manner, the force generated by the hydraulic pressure is exerted on the shock absorber50in a contraction direction. A member arranged at the boundary between the first rod61and the second rod62is not limited to the stopper67, and may be the piston65or the stopper66.

Further, the force generated by the hydraulic pressure is exerted upward on the stopper67, the first rod61coupled thereto, and the like, as described above. Thus, when the shock absorber50is contracted to move the first rod61upward, the piston102of the pressurizing mechanism100is also moved upward, that is, in a direction in which the oil is pressurized (seeFIG. 6). On the contrary, when the shock absorber50is extended to move the first rod61downward, the piston102of the pressurizing mechanism100is also moved downward (seeFIG. 5).

A rod-end coupling member80which extends in the vertical direction is mounted to the lower end portion of the first rod61. Specifically, the lower end portion of the first rod61is forced into an upper end portion of the rod-end coupling member80. The rod mounting member81is mounted to a lower end portion of the rod-end coupling member80. A through hole81apassing in a front-and-rear direction is formed in the rod mounting member81.

A flange portion82is provided on an upper end portion of the rod-end coupling member80. A spring seat83is provided on the flange portion82. A spring seat69is provided on a middle portion of the cylinder tube64. The spring52is supported between the spring seat69provided on the cylinder tube64and the spring seat83provided on the rod-end coupling member80. The spring52is arranged along the axis CA of the cylinder60to surround the cylinder60and the first rod61.

An adjuster84configured to adjust the damping force is provided on a middle portion of the rod-end coupling member80. The adjuster84radially moves an adjusting element841provided inside the rod-end coupling member80to vertically move an inner rod611provided inside the first rod61. Along with the vertical movement of the inner rod611, the needle valve612arranged above the inner rod611is also vertically moved. As a result, an opening degree of the sub-communication path61ais adjusted by the needle valve612.

The cylinder mounting member95is provided on the cap member90mounted to the upper end portion of the cylinder tube64. A through hole95apassing in the front-and-rear direction is formed in the cylinder mounting member95. The through hole81aformed in the rod mounting member81and the through hole95aformed in the cylinder mounting member95are oriented in the same direction to enable rocking of the shock absorber50.

The cylinder mounting member95is arranged as offset from the axis CA of the cylinder60. In other words, the cylinder mounting member95is provided on a radially outer side of the cylinder60with respect to the axis CA of the cylinder60. Specifically, the cylinder mounting member95is provided on the radially outer side of the cylinder60as compared to the second rod62so as not to interfere with the second rod62. Further, the cylinder mounting member95is arranged on the radially outer side of the cylinder60as compared to the cylinder60.

Further, the cylinder mounting member95is arranged below a position FE of the upper end of the second rod62when the shock absorber50is most contracted (seeFIG. 6). Further, the cylinder mounting member95is arranged below a center position HE of the second rod62in the vertical direction when the shock absorber50is most contracted. Meanwhile, the cylinder mounting member95is arranged above the second rod guide75that is provided on the upper end portion of the cylinder60. Further, the cylinder mounting member95is arranged above the upper end of the second rod62when the shock absorber50is most extended (seeFIG. 5).

Further, the cylinder mounting member95is offset from the axis CA of the cylinder60in a direction opposite to a side to which the pressurizing mechanism100is provided. Further, the cylinder mounting member95is provided at a position away from the cylinder portion93of the cap member90in the radial direction. The cap member90has a support portion94extending radially from the cylinder portion93. The cylinder mounting member95is provided on a distal end portion of the support portion94. The cylinder mounting member95is provided below an upper end of the cylinder portion93.

Still further, the axis CA of the cylinder60and an axis BB passing through the through hole95ain the cylinder mounting member95are skew lines not intersecting with each other or being parallel to each other in a three-dimensional space. Specifically, the axis CA of the cylinder60and the axis BB passing through the through hole95aof the cylinder mounting member95are radially away from each other, and thus do not intersect with each other. Further, the axis CA of the cylinder60extends in the vertical direction, whereas the axis BB passing through the through hole95aof the cylinder mounting member95extends in the front-and-rear direction. Therefore, the axis CA and the axis BB are not parallel to each other either.

As illustrated inFIG. 2, the rod mounting member81of the shock absorber50is coupled to the bracket421and provided on each of the lower arms42R and42L of the snowmobile1. Meanwhile, the cylinder mounting member95of the shock absorber50is coupled to each of the brackets301and provided on the vehicle body frame30of the snowmobile1. In this case, the cylinder mounting member95is positioned on an inner side of the cylinder60in a vehicle width direction. On the contrary thereto, the cylinder mounting member95may be positioned on an outer side of the cylinder60in the vehicle width direction. The target member to which the rod mounting member81is coupled and the target member to which the cylinder mounting member95is coupled may be interchanged. Specifically, the rod mounting member81may be coupled to a corresponding one of the brackets301and positioned on an upper side, whereas the cylinder mounting member95may be coupled to a corresponding one of the brackets421and positioned on a lower side.

FIG. 2illustrates a state in which the right ski41R is subjected to a larger reaction force from a snow surface than a reaction force to which the left ski41L is subjected so that the right shock absorber50R is more contracted than the left shock absorber50L. Therefore, the second rod62projects externally from the cap member90of the right shock absorber50R.

In this embodiment described above, the cylinder mounting member95is arranged as offset from the axis CA of the cylinder60, as illustrated inFIG. 3,FIG. 5, andFIG. 6. More specifically, the cylinder mounting member95is arranged on the radially outer side of the cylinder60as compared to the second rod62, and also is arranged on the radially outer side of the cylinder60as compared to the cylinder60. With this arrangement, the degree of freedom of the position of the cylinder mounting member95along the axial direction (vertical direction) of the cylinder60can be increased while ensuring a movable range of the second rod62.

Further, in this embodiment, the cylinder mounting member95is arranged as located on an axially inner (lower) side of an outer (upper) axial end of the second rod62when the shock absorber50is most contracted, as illustrated inFIG. 6. With this arrangement, an interval between the rod mounting member81and the cylinder mounting member95can be reduced as compared to a case without the above-mentioned characteristic.

Still further, in this embodiment, the cylinder mounting member95is arranged on an axially outer (upper) side of the second rod guide75, as illustrated inFIG. 5andFIG. 6. With this arrangement, an increase in angle formed between a straight line connecting the rod mounting member81and the cylinder mounting member95and the axis CA of the cylinder60can be suppressed as compared to the case without the above-mentioned characteristic. Further, the cylinder mounting member95can be arranged closer to the second rod62. As a result, a stress, exerted on the support portion94configured to support the cylinder mounting member95in a cantilever fashion, can be reduced.

Still further, in this embodiment, the cylinder mounting member95is provided on the radially outer side of the cylinder60with respect to the cylinder portion93of the cap member90mounted to the end portion of the cylinder tube64, as illustrated inFIG. 5andFIG. 6. With this arrangement, a length of the supporting portion94configured to support the cylinder mounting member95in a cantilever fashion can be reduced as compared to the case without the above-mentioned characteristic. Thus, strength against the stress exerted on the supporting portion94can be improved.

Still further, in this embodiment, the axis CA of the cylinder60and the axis BB passing through the through hole95aformed in the cylinder mounting member95are skew lines not intersecting with each other or being parallel to each other, as illustrated inFIG. 5andFIG. 6. With this arrangement, disturbance of the movable range of the second rod62by a target to be coupled such as the bracket to which the cylinder mounting member95is coupled and a coupling member such as a bolt used for coupling can be suppressed as compared to the case without the above-mentioned characteristic.

Still further, in this embodiment, the second rod guide75is provided on the end portion of the cylinder tube64, and the second rod62projects from the second rod guide75to outside of the cylinder tube64, as illustrated inFIG. 5andFIG. 6. With this arrangement, a length of the cylinder tube64can be reduced as compared to the case without the above-mentioned characteristic, which can eventually reduce a total length of the shock absorber50.

Still further, in this embodiment, the pressurizing mechanism100is arranged outside of the cylinder tube64, as illustrated inFIG. 5andFIG. 6. With this arrangement, the length of the cylinder tube64can be reduced as compared to the case without the above-mentioned characteristic, which can eventually reduce the total length of the shock absorber50.

Still further, in this embodiment, the cylinder mounting member95is provided on the side opposite to the side to which the pressurizing member100is provided, with respect to the axis CA of the cylinder60, as illustrated inFIG. 5andFIG. 6. With this arrangement, inhibition of the coupling of the cylinder mounting member95by the pressurizing mechanism100can be suppressed to improve ease of layout of the shock absorber50as compared to the case without the above-mentioned characteristic.

Still further, in this embodiment, the spring52is arranged as inclined with respect to the straight line connecting the rod mounting member81and the cylinder mounting member95along the axis CA of the cylinder60, as illustrated inFIG. 5andFIG. 6. With this arrangement, a spring force of the spring52can be more directly exhibited for the extension and contraction of the damper51.

The arrangement of the spring52is not limited to the above-mentioned case. As in a modification example illustrated inFIG. 7, the spring52may be arranged as inclined with respect to the axis CA of the cylinder60. In this modification example, an upper spring seat691provided on the cylinder tube64is formed to extend in an offset direction of the cylinder mounting member95, whereas a lower spring seat831provided on the rod-end coupling member80is formed to extend in a direction opposite to the offset direction. The spring52is arranged along a straight line CL connecting the rod mounting member81and the cylinder mounting member95when the piston65is located in the middle of the cylinder60, for example, when the shock absorber50is compressed by about ⅓ from a most extended state. With this arrangement, a bending force applied to the first rod61as a result of the compression of the spring52can be reduced.

Further, as in a modification example illustrated inFIG. 8, the spring52may be arranged as offset from the axis CA of the cylinder60. In this modification example, the spring52is offset to the same direction in which the cylinder mounting member95is offset with respect to the axis CA of the cylinder60, while being arranged along the axis CA of the cylinder60. A spring seat693provided on the cylinder tube64and a spring seat833provided on the rod-end coupling member80are formed to extend in the offset direction of the cylinder mounting member95. With this arrangement, the bending force applied to the first rod61as a result of the compression of the spring52can be reduced as in the embodiment described above.

Still further, in this embodiment, the rod mounting members81of the shock absorbers50are mounted to the lower arms42R and42L of the snowmobile1, respectively, whereas the cylinder mounting members95of the shock absorbers50are mounted to the vehicle body frame30of the snowmobile1, as illustrated inFIG. 2. With this configuration, the second rods62project upward. Thus, it is not necessary to take a clearance between each of the second rods62and the ground surface into consideration.

Still further, in this embodiment, each of the cylinder mounting members95is positioned on the inner side of the cylinder60in the vehicle width direction, as illustrated inFIG. 2. Specifically, the cylinder mounting members95are offset in a direction toward the vehicle body. With this arrangement, interference between the vehicle body frame30to which the cylinder mounting members95are mounted and the cylinders60can be suppressed to improve the ease of layout of the shock absorber50.

The shock absorber according to the present application is not limited to the embodiment described above. For example, as disclosed in Japanese Patent Application Laid-open No. 2010-96347, the length of the cylinder tube may be set long and the second rod guide may be provided in the middle of the cylinder tube so that the second rod (sub-rod) is movable only on the inner side of the cylinder tube. Further, as disclosed in Japanese Patent Application Laid-open No. 2010-96347, the pressurizing mechanism including the spring may be provided on the inner side of the cylinder tube. Further, the shock absorber according to the embodiment may be applied to the shock absorber19(seeFIG. 1) arranged inside of the track belt16.

A modification example in which the shock absorber according to the embodiment is applied to a vehicle for running on an irregular ground is now described. In the following description, configuration elements common to those of the above-mentioned embodiment are denoted by the same reference symbols, and detailed description thereof is herein omitted.

FIG. 9is a front view of a vehicle200, andFIG. 10is a front view of a vehicle300, to each of which the above-mentioned shock absorbers50R and50L are applied. The vehicle200illustrated inFIG. 9is a saddle type four-wheeled vehicle called an “all-terrain vehicle (ATV)”, which includes a steering bar201. The vehicle300illustrated inFIG. 10is a four-wheeled vehicle called a “recreational off-highway vehicle (ROV)”, which includes a plurality of seats308arranged in the vehicle width direction and a steering wheel309.

As illustrated inFIG. 9andFIG. 10, each of the vehicles200and300has front wheels46R and46L arranged on both the right and left of the front part of the vehicle body frame30as grounded portions. The right front wheel46R is supported by the lower arm42R and the upper arm43R, whereas the left front wheel46L is supported by the lower arm42L and the upper arm43L. The base portions of the arms42R,43R,42L, and43L are coupled to the vehicle body frame30to be rotatable. As a result, the front wheels46R and46L are vertically movable relative to the vehicle body frame30.

Each of the vehicles200and300includes the shock absorbers50R and50L. The shock absorber50R includes the damper51R and the spring52R, whereas the shock absorber50L includes the damper51L and the spring52L. The rod mounting members81provided on lower portions of the shock absorbers50R and50L are coupled to the brackets421provided on the lower arms42R and42L in the vehicle200and are coupled to the brackets421provided on the upper arms43R and43L in the vehicle300. Meanwhile, the cylinder mounting members95provided on the upper portions of the shock absorbers50are coupled to the brackets301provided on the vehicle body frame30. The shock absorbers50R and50L are used not only to suspend the front wheels46R and46L but may also be used to suspend rear wheels (not shown).