Patent Description:
In PTL <NUM>, a hydraulic shock absorber where a push rod is placed through a hollow portion of a hollow rod and a suspension spring is pressurized by the push rod, and further the push rod is moved up and down by an adjuster to adjust a spring load of the suspension spring is disclosed.

PTL <NUM> shows a hydraulic shock absorber in which a vehicle body side tube and a wheel side tube are slidably fitted together, and a damper cylinder is erected from a lower portion of the wheel side tube, and a cap is screwed onto an upper portion of the vehicle body side tube. The adjustment rod is rotatably and axially movably connected to the central hollow part of the cap, and the cap is composed of the main body and the body having a width across flats provided in the lower part of the body. The upper part of the piston rod is fixed, a radial through hole is formed in the middle of the body, and a washer that is movable in the axial direction is inserted into the body through this through hole. The lower end is abutted, and the seat portion protruding on the outer periphery of the washer body is projected outward from the through hole, so that the lower surface of the seat portion carries the upper portion of the suspension spring directly or through a spacer.

PTL <NUM> shows a structure of adjusting a spring load that comprises an adjusting rod locking a spring body with its base end as a fixed end, at its front end as a moving end, and movable forward and backward in the expanding direction of the spring body during turning while being threaded to a rod body inserted through an axial core portion of the spring body or to a supporting member connected to a cylindrical body. The rod body inserted through the axial core portion of the spring body or the cylindrical body is connected to an axial core portion of the supporting member, while the adjusting rod is threaded to a portion offset from the axial core portion of the supporting member.

Depending on the structure of a shock absorber, a suspension spring may not be arranged at a tip end of a hollow rod because a piston is arranged at the tip end of the hollow rod. In this case, it is necessary to arrange the suspension spring outside the hollow rod. A spring load adjusting mechanism described in PTL <NUM> cannot be applied to a structure in which a suspension spring is disposed outside a hollow rod.

An object of the invention is to provide a shock absorber capable of setting a position of a suspension spring with a simple configuration in a configuration in which the suspension spring is arranged outside a hollow rod.

To solve the problem described above, according to an aspect of the invention, there is provided a shock absorber with the features of claim <NUM>. The shock absorber includes a hollow rod, a suspension spring arranged outside the hollow rod, a spring receiver arranged to be displaceable with respect to the hollow rod and receiving a load of the suspension spring, an adjusting screw inserted into one end side of the hollow rod and configured to adjust a position of the suspension spring by restricting movement of the spring receiver to the one end side, and a shaft member which transmits a load received by the spring receiver to the adjusting screw inside the hollow rod, where, on a side surface of the hollow rod, an insertion portion which extends in an axial direction of the hollow rod and into which the shaft member is inserted is provided. The shock absorber further comprises a cylinder arranged outside the suspension spring, a cap member which is disposed in an opening portion on one end side of the cylinder and into which the hollow rod is inserted, and a nut configured to fix the hollow rod to the cap member, wherein the nut is arranged closer to one end side than the spring receiver, wherein the adjusting screw is inserted coaxially with the hollow rod at the one end portion of the hollow rod, wherein screw grooves formed on the outer peripheral surface of the adjusting screw and the inner peripheral surface of the hollow rod are screwed together, so that by rotating the adjusting screw, the adjusting screw can be moved up and down, whereby the shaft member and the spring receiver can be moved up and down.

According to the aspect of the invention, it is possible to provide a shock absorber capable of setting a position of a suspension spring with a simple configuration in a configuration in which the suspension spring is disposed outside a hollow rod.

In the following, a direction from a vehicle body to an axle or an opposite direction may be referred to as an "axial direction". The axial direction is a direction parallel to an x-axis in <FIG> and the like. A direction (arbitrary direction parallel to a y-z plane) perpendicular to the axial direction may be referred to as a "radial direction".

<FIG> is a cross-sectional view illustrating a configuration of a shock absorber <NUM> according to the present embodiment. As illustrated in <FIG>, the shock absorber <NUM> includes an outer tube <NUM> (cylinder), an inner tube <NUM>, and an inner rod <NUM> (hollow rod).

The shock absorber <NUM> is an inverted-type shock absorber in which the outer tube <NUM> is disposed on a vehicle body side (one end side) and the inner tube <NUM> is disposed on an axle side (the other end side). Further, the shock absorber according to an aspect of the invention may be an upright-type shock absorber in which the outer tube is disposed on the axle side and the inner tube is disposed on the vehicle body side.

The outer tube <NUM> is a cylindrical member having one end fixed to the vehicle body side and the other end opened to the axle side. The inner tube <NUM> is a cylindrical member having one end fixed to the axle side and the other end opened to the vehicle body side. The inner tube <NUM> is inserted into the outer tube <NUM> from the axle side. A bush <NUM> is provided on an axle-side inner peripheral surface of the outer tube <NUM> and the outer tube <NUM> is slidable with respect to the inner tube <NUM>. Further, an oil seal <NUM> and a dust seal <NUM> are provided at an axle-side end portion of the outer tube <NUM>.

The inner rod <NUM> is a rod which is inserted into an oil chamber cylinder <NUM> (described below) from the vehicle body side and has a piston <NUM> at an axle-side end portion. Specifically, the inner rod <NUM> has a configuration in which a hollow first rod <NUM> located on the vehicle body side and a solid second rod <NUM> located on the axle side are connected. The piston <NUM> is disposed at the axle-side end portion of the second rod <NUM>. Even in a state where the shock absorber <NUM> is most compressed, only the second-rod -<NUM> portion of the inner rod <NUM> is inserted into the oil chamber cylinder <NUM>.

The oil chamber cylinder <NUM> is a cylindrical member disposed coaxially with the inner tube <NUM> and is erected in the inner tube <NUM>. The oil chamber cylinder <NUM> has a double structure in which an inner cylinder 25a and an outer cylinder 25b are arranged coaxially. A rod guide <NUM> through which the inner rod <NUM> passes is provided at the vehicle-body-side end portion of the oil chamber cylinder <NUM>. The piston <NUM> disposed on the axle side of the inner rod <NUM> slides liquid-tightly with respect to the inner cylinder 25a. An oil chamber S is defined by the inner cylinder 25a and the piston <NUM>. The oil chamber S is filled with hydraulic oil.

An attachment member <NUM> for attaching the shock absorber <NUM> to the axle is provided at the axle-side end portions of the inner tube <NUM> and the oil chamber cylinder <NUM>. The attachment member <NUM> is provided with a damping force generator <NUM> and a sub tank <NUM>.

The damping force generator <NUM> generates a damping force by the flow of hydraulic oil generated by the reciprocating motion of the piston <NUM>. A communication hole <NUM> which allows the oil chamber S and the damping force generator <NUM> to communicate with each other is provided in the vicinity of the axle-side end portion of the inner cylinder 25a.

The sub tank <NUM> communicates with the oil chamber S via the damping force generator <NUM> and compensates for the hydraulic oil corresponding to the volume of the inner rod <NUM> entering the inner cylinder 25a.

A suspension spring <NUM> is provided outside the inner rod <NUM>. Specifically, the suspension spring <NUM> is disposed in an annular space between the outer peripheral surface of the outer cylinder 25b outside the inner rod <NUM> and the inner peripheral surface of the inner tube <NUM>. The suspension spring <NUM> is a member for buffering an impact applied to the shock absorber <NUM>. A spring receiver <NUM> which abuts against the axle-side end portion of the suspension spring <NUM> is provided at the axle-side end portion in the inner tube <NUM>.

A spring receiver <NUM> which receives the load of the suspension spring <NUM> is disposed on the vehicle body side of the suspension spring <NUM>. In the embodiment, the spring receiver <NUM> is a cylindrical member into which the first rod <NUM> is inserted. However, the spring receiver <NUM> does not necessarily have a cylindrical shape and may have a shape in which a part of the cylindrical shape is removed, for example. The spring receiver <NUM> has a hole extending in a direction (more preferably, a radial direction perpendicular to the axial direction) intersecting the axial direction through which a pin (shaft member) <NUM> described below passes. The spring load received by the spring receiver <NUM> is transmitted to an adjusting screw <NUM> via the pin <NUM>.

A cylindrical spring collar <NUM> is disposed between the suspension spring <NUM> and the spring receiver <NUM>. The spring collar <NUM> transmits the load of the suspension spring <NUM> to the spring receiver <NUM>. By adjusting the length of the spring collar <NUM>, a suspension spring mechanism suitable for the distance between the spring receiver <NUM> and the axle-side spring receiver <NUM> can be configured without adjusting the length of the suspension spring <NUM>. However, the spring collar <NUM> may be omitted and the suspension spring <NUM> may be disposed over the entirety between the spring receiver <NUM> and the axle-side spring receiver <NUM>.

<FIG> is an enlarged cross-sectional view illustrating the structure in a vicinity of the vehicle-body side end portion of the shock absorber <NUM>. As illustrated in <FIG>, the adjustment screw <NUM> is inserted coaxially with the inner rod <NUM> at the vehicle-body-side end portion of the inner rod <NUM>. Screw grooves (not illustrated) formed on the outer peripheral surface of the adjusting screw <NUM> and the inner peripheral surface of the inner rod <NUM> are screwed together. By rotating the adjusting screw <NUM>, the adjusting screw <NUM> can be moved up and down, whereby the spring collar <NUM> connected to the first rod <NUM> via the pin <NUM> and the spring receiver <NUM> can be moved up and down. Therefore, the load of the suspension spring <NUM> which comes into contact with the spring collar <NUM> can be adjusted.

The adjusting screw <NUM> may be any member as long as it has a function as a general screw. For example, a standard hexagon bolt can be used as the adjusting screw <NUM>. Since standard hexagon bolts are less expensive than dedicated parts, the manufacturing cost of the shock absorber <NUM> can be reduced.

A pair of long holes (insertion portions) <NUM> into which the pin <NUM> is inserted are formed on the side surfaces of the inner rod <NUM>. The long hole <NUM> may be formed by, for example, pressing or other processing methods (such as cutting). The long holes <NUM> are formed at two locations so as to face each other through the axis of the inner rod <NUM>. The pin <NUM> passes through the two long holes <NUM> and is arranged perpendicular to the axial direction of the inner rod <NUM>.

The long hole <NUM> extends in the axial direction of the inner rod <NUM>. Accordingly, the pin <NUM> is movable along the axial direction of the inner rod <NUM> in a state where the pin <NUM> is inserted into the long holes <NUM>. Therefore, the spring receiver <NUM> can be displaced with respect to the inner rod <NUM> by the length of the long hole <NUM>.

Further, the pin <NUM> is in contact with the axle-side end portion of the adjusting screw <NUM> in a state where the pin <NUM> is inserted into the long hole <NUM>. Therefore, the load received by the spring receiver <NUM> is transmitted to the adjusting screw <NUM> via the pin <NUM>. The adjusting screw <NUM> adjusts the position of the vehicle-body-side end portion of the suspension spring <NUM> by restricting the movement of the spring receiver <NUM> to the vehicle body side via the pin <NUM>. The load of the suspension spring <NUM> is adjusted by adjusting the position.

A cap member <NUM> is fitted into the vehicle-body-side end portion of the outer tube <NUM>. The vehicle-body-side end portion of the inner rod <NUM> is inserted into the cap member <NUM>. A relative position of the inner rod <NUM> with respect to the cap member <NUM> is fixed by a nut <NUM>. Further, at least a part on the vehicle body side of the adjusting screw <NUM> is disposed inside the cap member <NUM>.

<FIG> is a view illustrating a state where the cap member <NUM> is viewed from the vehicle body side. As illustrated in <FIG> and <FIG>, the cap member <NUM> includes a cap body <NUM> and an operation portion <NUM> which rotates the adjusting screw <NUM>. The operation unit <NUM> may be a member which includes, for example, a fitting portion which fits with, for example, the head of the adjusting screw <NUM> on the axle side and is rotatable relative to the cap body <NUM> around the axis of the adjusting screw <NUM>. The operation portion <NUM> includes a plurality of protrusions 13a on the surface on the vehicle body side. The operation portion <NUM> is rotated with respect to the cap body <NUM> by fitting a tool for rotating the operation portion <NUM> into the protrusion 13a and rotating the tool. By this operation, the adjusting screw <NUM> rotates and moves up and down in the axial direction.

The cap member <NUM> does not necessarily include the operation portion <NUM>. For example, the cap member <NUM> may include a window portion which exposes the head of the adjusting screw <NUM> to the outside and may be configured to be directly accessible to the adjusting screw <NUM>.

<FIG> is a cross-sectional view illustrating a state where the outer tube <NUM> is removed from the shock absorber <NUM>. The description will be continued with reference to <FIG> and <FIG>. In the embodiment, the nut <NUM> is disposed further on the vehicle body side than the spring receiver <NUM>. Therefore, as illustrated in <FIG>, access to the nut <NUM> is not hindered by the spring receiver <NUM> and the spring collar <NUM>. Therefore, as illustrated in <FIG>, the nut <NUM> can be easily accessed without compressing the suspension spring <NUM> by simply removing the outer tube <NUM>. The adjusting screw <NUM> and the cap member <NUM> can be removed from the inner rod <NUM> by removing the nut <NUM>.

<FIG> is a cross-sectional view illustrating a state where the adjusting screw <NUM> and the cap member <NUM> are removed from the shock absorber <NUM> in a state illustrated in <FIG>. The description will be continued with reference to <FIG> and <FIG>. As illustrated in <FIG>, in the shock absorber <NUM>, the long hole <NUM> has a contour closed on the vehicle body side. That is, a dead end which restricts the movement of the pin <NUM> toward the vehicle body is formed in the long hole <NUM>. Therefore, it is possible to prevent the pin <NUM>, the spring receiver <NUM>, and the spring collar <NUM> from jumping out due to the reaction force of the suspension spring <NUM> when the adjusting screw <NUM> is removed in the process of disassembling the shock absorber <NUM>.

In the embodiment, the pin <NUM> is detachable from the spring receiver <NUM>. When the pin <NUM> is detached (withdrawn) from the spring receiver <NUM>, the movement of the spring receiver <NUM> toward the vehicle body side is not limited to the adjusting screw <NUM>. In this case, not only the spring receiver <NUM> but also the suspension spring <NUM> can be moved to the vehicle body side in the same manner. Therefore, in the shock absorber <NUM> in the state illustrated in <FIG>, the suspension spring <NUM> can be removed by a simple operation of pulling out the pin <NUM> from the spring receiver <NUM>.

Thus, the shock absorber <NUM> is easier to disassemble than the shock absorber of the related art. In particular, when the shock absorber <NUM> is applied to a motorcycle used for a race or the like, the frequency of replacing the suspension spring <NUM> is higher than that applied to a general vehicle, and thus easy to disassemble is very important. Therefore, the shock absorber <NUM> can be suitably used for a motorcycle used for a race or the like.

As described above, the shock absorber <NUM> includes the inner rod <NUM>, the suspension spring <NUM> disposed outside the inner rod <NUM>, the spring receiver <NUM> which is disposed so as to be displaceable with respect to the inner rod <NUM> and receives the load of the suspension spring <NUM>, the adjusting screw <NUM> which is inserted into one end side of the inner rod <NUM> and adjusts the position of the suspension spring <NUM> by restricting the movement of the spring receiver <NUM> to the vehicle body side, and the pin <NUM> which transmits the load received by the spring receiver <NUM> to the adjusting screw <NUM> inside the inner rod <NUM>. The inner rod <NUM> has the long hole <NUM> which extends in the axial direction of the inner rod <NUM> and into which the pin <NUM> is inserted.

The load of the suspension spring <NUM> received by the spring receiver <NUM> is transmitted via the pin <NUM> to the adjusting screw <NUM> inserted into the vehicle body side of the inner rod <NUM>. The pin <NUM> is fixed by being inserted into the long hole <NUM> formed on the side surface of the inner rod <NUM> and the adjusting screw <NUM> and the pin <NUM> are in contact with each other inside the inner rod <NUM>. Further, the long hole <NUM> extends in the axial direction of the inner rod <NUM> and the pin <NUM> is movable in the axial direction along the long hole <NUM>. Therefore, the position of the spring receiver <NUM> can be adjusted by moving the pin <NUM> in the axial direction by the adjusting screw <NUM>, and as a result, the position of the suspension spring <NUM> can be set. Thus, even in the configuration in which the suspension spring <NUM> is disposed outside the inner rod <NUM>, the position of the suspension spring <NUM> can be set with a simple configuration. Thereby, the spring load can be adjusted.

In the shock absorber <NUM>, the long hole <NUM> is an opening portion having a closed contour. By making the long hole <NUM> into a shape having a closed contour instead of a notch groove, a dead end which restricts the movement of the pin <NUM> is formed on the vehicle body side. This dead end can prevent the pin <NUM>, the spring receiver <NUM>, and the suspension spring <NUM> from jumping out of the shock absorber <NUM> even when the load by the adjusting screw <NUM> is removed.

The shock absorber <NUM> includes the outer tube <NUM> arranged outside the suspension spring <NUM>, the cap member <NUM> which is disposed in the opening portion on the vehicle body side of the outer tube <NUM> and into which the inner rod <NUM> is inserted, and the nut <NUM> for fixing the inner rod <NUM> to the cap member <NUM>. The nut <NUM> is arranged further on the vehicle body side than the spring receiver <NUM>.

Since the nut <NUM> which fixes the inner rod <NUM> to the cap member <NUM> is arranged further on the vehicle body side than the spring receiver <NUM>, the suspension spring <NUM> which abuts on the spring receiver <NUM> does not hinder the access to the nut <NUM>. Therefore, the suspension spring <NUM> can be easily exchanged.

The shock absorber <NUM> further includes the spring collar <NUM> disposed between the spring receiver <NUM> and the suspension spring <NUM>.

By adjusting the length of the spring collar <NUM>, the suspension spring mechanism suitable for the distance between the spring receiver <NUM> and the axle-side spring receiver <NUM> can be realized without adjusting the length of the suspension spring <NUM>. Further, by disposing the nut <NUM> closer to the vehicle body side than the spring receiver <NUM>, it is possible to prevent the access to the nut <NUM> from being hindered by the spring collar <NUM>.

In the shock absorber <NUM>, the pin <NUM> can be detachable from the spring receiver <NUM>. Therefore, since the movement restriction of the spring receiver <NUM> toward the vehicle body side can be released by a simple operation of pulling out the pin <NUM> from the spring receiver <NUM>, the suspension spring <NUM> can be easily replaced.

Further, in the shock absorber <NUM>, at least a part of the vehicle body side of the adjusting screw <NUM> is disposed inside the cap member <NUM> and the cap member <NUM> includes the operation portion <NUM> which rotates the adjusting screw <NUM>. Therefore, the initial load of the suspension spring <NUM> can be easily set by adjusting the position of the adjusting screw <NUM> by the operation portion <NUM>.

Another embodiment of the invention will be described below.

<FIG> is a cross-sectional view illustrating the configuration of a shock absorber <NUM> according to the embodiment. The shock absorber <NUM> is different from the shock absorber <NUM> in that the inner rod <NUM> has a notch portion <NUM> instead of the long hole <NUM>. The notch portion <NUM> extends in the axial direction of the inner rod <NUM>, similarly to the long hole <NUM>. On the other hand, the notch portion <NUM> is different from the long hole <NUM> in that the vehicle body side is not closed.

In the shock absorber <NUM>, the spring receiver <NUM> can be removed from the inner rod <NUM> by removing the nut <NUM> without pulling out the pin <NUM> from the spring receiver <NUM>. Therefore, according to the shock absorber <NUM>, compared with the shock absorber <NUM>, the time required for replacement of the suspension spring <NUM> can be shortened. In addition, it is easier to form the notch portion <NUM> in the inner rod <NUM> than to form the long hole <NUM>. In the shock absorber <NUM>, the pin <NUM> and the spring receiver <NUM> may be formed integrally without making the pin <NUM> detachable from the spring receiver <NUM>.

Such a shock absorber <NUM> can set the load of the suspension spring <NUM> with a simple configuration, similarly to the shock absorber <NUM>.

<FIG> is a side view of a spring receiver <NUM> according to the embodiment. <FIG> is a cross-sectional view taken along the line A-A in <FIG>.

The spring receiver <NUM> is a member which can be used in place of the spring receiver <NUM> in the shock absorber <NUM> or <NUM> described above. The spring receiver <NUM> has a shape in which a part of the cylindrical shape is removed. Specifically, as illustrated in <FIG>, the spring receiver <NUM> has an insertion portion 44a extending in the axial direction. The first rod <NUM> is inserted into the insertion portion 44a. In addition, the insertion portion 44a is not a through hole having a closed contour. In the cross section (the cross section illustrated in <FIG>) when the insertion portion 44a is cut along a plane perpendicular to the axial direction, a part of the contour of the insertion portion 44a is opened. This open portion is formed over the entire axial direction of the spring receiver <NUM>, as illustrated in <FIG>.

Therefore, when the spring receiver <NUM> is removed from the inner rod <NUM>, if the pin <NUM> is pulled out from the spring receiver <NUM>, the spring receiver <NUM> can be removed in the radial direction without removing the nut <NUM>. Therefore, when the shock absorber <NUM> or <NUM> includes the spring receiver <NUM>, the time required to replace the suspension spring <NUM> can be shortened as compared with a case where the shock receiver <NUM> or <NUM> includes the spring receiver <NUM>.

Claim 1:
A shock absorber (<NUM>, <NUM>), comprising:
a hollow rod (<NUM>);
a suspension spring (<NUM>) arranged outside the hollow rod (<NUM>);
a spring receiver (<NUM>, <NUM>) arranged to be displaceable with respect to the hollow rod (<NUM>) and receiving a load of the suspension spring (<NUM>);
an adjusting screw (<NUM>) inserted into one end side of the hollow rod (<NUM>) and configured to adjust a position of the suspension spring (<NUM>) by restricting movement of the spring receiver (<NUM>, <NUM>) to the one end side; and
a shaft member (<NUM>) which transmits a load received by the spring receiver (<NUM>, <NUM>) to the adjusting screw (<NUM>) inside the hollow rod (<NUM>), wherein
an insertion portion (<NUM>, <NUM>) which extends in an axial direction of the hollow rod (<NUM>) and into which the shaft member (<NUM>) is inserted is provided on a side surface of the hollow rod (<NUM>),
a cylinder (<NUM>) arranged outside the suspension spring (<NUM>), characterized in that the shock absorber further comprises:
a cap member (<NUM>) which is disposed in an opening portion on one end side of the cylinder (<NUM>) and into which the hollow rod (<NUM>) is inserted; and
a nut (<NUM>) configured to fix the hollow rod (<NUM>) to the cap member (<NUM>), wherein the nut (<NUM>) is arranged closer to one end side than the spring receiver (<NUM>, <NUM>),
wherein the adjusting screw (<NUM>) is inserted coaxially with the hollow rod (<NUM>) at the one end portion of the hollow rod (<NUM>), wherein screw grooves formed on the outer peripheral surface of the adjusting screw (<NUM>) and the inner peripheral surface of the hollow rod (<NUM>) are screwed together, so that by rotating the adjusting screw (<NUM>), the adjusting screw (<NUM>) can be moved up and down, whereby the shaft member (<NUM>) and the spring receiver (<NUM>) can be moved up and down.