Patent Description:
<CIT> discloses a hydraulic damper which is provided with a bum stopper. Said bum stopper comprises a bump cap fitted on and fixedly secured to a packing cap which is, in turn, fitted on and fixedly secured to one end of a cylinder main body the damper. Said bum stopper further comprises a bump plate assembly including a bump plate for directly abutting a bump rubber and a plate cap integrally connected to said bump plate.

A bump stopper that absorbs shocks generated during maximum contraction of a shock absorber is also known from <CIT> and <CIT>. The bump stoppers disclosed in <CIT> and <CIT> are mounted on an end of a cylinder body into which a piston rod is movably inserted, or mounted on an end of an outer tube that accommodates a cylinder body. Shocks during maximum contraction of the piston rod are absorbed by the bump stopper and a bump cushion provided to the top end of the piston rod.

The bump stopper disclosed in <CIT> includes the following: a horizontal plate that receives a bump cushion; a folded part that extends downwards from the horizontal plate and is folded; and a communication hole formed in the folded part. An insertion hole into which the piston rod is inserted is provided to the center of the horizontal plate. The folded part is disposed on an end of a cylinder body in a state in which the piston rod is inserted into the insertion hole of the horizontal plate, and the folded part secures a space between the horizontal plate and the cylinder body. Muddy water and dust that have flowed into this space from a gap between the horizontal plate and the piston rod is discharged to the outside of the bump stopper via the communication hole of the folded part.

<CIT> discloses a disc-shaped bump stopper. A protrusion is formed on the bottom surface of the disc-shaped bump stopper. The distal end of the protrusion is welded to a caulked part of an outer tube of a shock absorber, and a space is secured between a flat plate of the bump stopper and the caulked part by the protrusion. Dust that has flowed into this space from a gap between the bump stopper and a piston rod is discharged via a passage formed on the bottom surface of the flat plate. Document <CIT> discloses a bump stopper which is considered the closest prior art.

In the bump stopper disclosed in <CIT>, the folded part is formed by folding a pipe material or a flat plate by press machining. In the folded part, the folding angle is large (about <NUM> degrees), and thus cracks can easily form in the folded part when folding the pipe material or flat plate. Consequently, the manufacturing of such a bump stopper requires advanced technology.

In the bump stopper disclosed in <CIT>, the protrusion is formed by depressing a portion of the top surface of the flat plate. Therefore, the bump stopper can easily be deformed back to its original flat plate shape having no protrusion or recess when the shock absorber contracts to the maximum degree and receives a shock from the bump cushion, and thus the bump stopper may not have sufficient strength.

In this way, the bump stoppers disclosed in <CIT> and <CIT> have a complex shape due to the folded part or the protrusion, and thus these bump stoppers are not only difficult to manufacture but also may not have sufficient strength.

An object of the present invention is to provide a bump stopper that is easy to manufacture and has sufficient strength.

This object is solved according to the present invention by providing a bump stopper for absorbing shocks generated during maximum contraction of a shock absorber in cooperation with a bump cushion, the bump stopper comprising: a cap including a plate-shaped part having a rod hole into which a piston rod of the shock absorber may be inserted, and a cylindrical part configured to receive a portion of a cylinder of the shock absorber; a stopper provided to the plate-shaped part, the stopper being configured to receive the bump cushion; and a collar provided to the plate-shaped part configured so that it opposes the cylinder in an assembled state, wherein the collar comprises a plurality of support parts arranged in a radial manner on the plate-shaped part, the plurality of support parts being configured to support the plate-shaped part, a passage is formed by the cap and the collar, the passage being configured to allow the rod hole to communicate with an outside of the cylindrical part via an inside of the cylindrical part, and the passage is formed between the adjacent support parts.

Embodiments of the present invention will now be explained below referring to the drawings. Herein, a hydraulic shock absorber in which hydraulic oil is used as a working fluid shall be explained, but other fluids such as a working water may also be used as the working fluid.

First, referring to <FIG>, a bump stopper <NUM> according to a first embodiment of the present invention and a shock absorber <NUM> equipped with the bump stopper <NUM> will be explained. The shock absorber <NUM> is provided, for example, between a vehicle body <NUM> and a wheel shaft (not illustrated) of a vehicle, and generates a damping force to suppress vibrations of the vehicle body <NUM>.

As shown in <FIG>, the shock absorber <NUM> includes a cylinder <NUM> in which hydraulic oil is sealed, and a piston rod <NUM> inserted into the cylinder <NUM> such that the piston rod <NUM> can move into and out of the cylinder <NUM>. A piston (not illustrated) is slidably accommodated in the cylinder <NUM>, and one end of the piston rod <NUM> is connected to the piston. The inside of the cylinder <NUM> is partitioned by the piston into an extension-side chamber <NUM> and a contraction-side chamber (not illustrated).

The cylinder <NUM> includes the following: an approximately cylindrical tube <NUM>; a rod guide <NUM> provided to one end of the tube <NUM>; and an oil seal <NUM>. The rod guide <NUM> and the oil seal <NUM> are fixed to the tube <NUM> by bending the end of the tube <NUM> toward the inside.

The rod guide <NUM> is formed in an annular shape, and a bush <NUM> is provided to the inner periphery of the rod guide <NUM>. The piston rod <NUM> is slidably supported by the rod guide <NUM> via the bush <NUM>.

The oil seal <NUM> includes an annular base metal 14a, and lips 14b, 14c provided to the inner periphery of the base metal 14a. The lips 14b, 14c are joined to the base metal 14a by vulcanization adhesion.

The lip 14b slidingly contacts the piston rod <NUM>, and prevents hydraulic oil within the cylinder <NUM> from leaking to the outside. The lip 14c slidingly contacts the piston rod <NUM>, and prevents foreign contaminants from flowing into the cylinder <NUM>.

A male screw <NUM> is formed on the other end of the piston rod <NUM>. A nut (not illustrated) threadably engages with the male screw <NUM> in a state in which the male screw <NUM> is inserted into a hole 5a of the vehicle body <NUM>, and thereby the piston rod <NUM> is fixed to the vehicle body <NUM>.

A bottom member (not illustrated) is attached to the other end of the tube <NUM>, and the opening of the tube <NUM> is blocked by the bottom member. A connection part (not illustrated) to be attached to the wheel shaft is provided to the bottom member, and the bottom member (cylinder <NUM>) is connected by the connection part.

The aforementioned piston includes first and second piston passages that allow the extension-side chamber <NUM> to communicate the contraction-side chamber. First and second damping valves are provided respectively to the first and second piston passages.

The first damping valve is opened by a pressure difference between the contraction-side chamber and the extension-side chamber <NUM> during contraction of the shock absorber <NUM>, and thereby the first damping valve opens the first piston passage and applies resistance to the flow of hydraulic oil moving from the contraction-side chamber to the extension-side chamber <NUM> via the first piston passage. The first damping valve closes the first piston passage during extension of the shock absorber <NUM>.

The second damping valve is opened by a pressure difference between the extension-side chamber <NUM> and the contraction-side chamber during extension of the shock absorber <NUM>, and thereby the second damping valve opens the second piston passage and applies resistance to the flow of hydraulic oil moving from the extension-side chamber <NUM> to the contraction-side chamber via the second piston passage. The second damping valve closes the second piston passage during contraction of the shock absorber <NUM>.

In this way, the shock absorber <NUM> generates a damping force in accordance with the extension/contraction operations to suppress vibrations of the vehicle body <NUM>.

The shock absorber <NUM> further includes a bump cushion <NUM> provided to the outer periphery of the piston rod <NUM> between the cylinder <NUM> and the vehicle body <NUM>, and the bump stopper <NUM> attached to the cylinder <NUM>.

The bump cushion <NUM> is made of a contractible material. When the bump cushion <NUM> abuts the bump stopper <NUM> and contracts during contraction of the shock absorber <NUM>, shocks generated by the operation of the shock absorber <NUM> are absorbed. In this way, the bump stopper <NUM> cooperates with the bump cushion <NUM> to absorb shocks generated during maximum contraction of the shock absorber <NUM>.

As shown in <FIG>, the bump stopper <NUM> includes the following: a cap <NUM> that covers the top end side of the cylinder <NUM>; a stopper <NUM> that is supported by the cap <NUM>; and a collar <NUM> that is provided to the inside of the cap <NUM>.

The cap <NUM> is provided with a plate-shaped part <NUM> having a first rod hole <NUM> into which the piston rod <NUM> can be inserted, and a cylindrical part <NUM> which can receive the top end side of the cylinder <NUM>. The first rod hole <NUM> is formed so as to penetrate between a first surface (inner surface) 111a and a second surface (outer surface) 111b of the plate-shaped part <NUM>. Hereinafter, the first rod hole <NUM> will also be referred to simply as the "rod hole <NUM>".

<FIG> are bottom surface views of the collar <NUM>, the cap <NUM>, and the stopper <NUM>, respectively. In <FIG>, the piston rod <NUM> is depicted with dot-dash lines.

As shown in <FIG>, the rod hole <NUM> is positioned in approximately the center of the plate-shaped part <NUM>. The inner peripheral surface of the rod hole <NUM> includes the following: a plurality of curved surface parts 112a formed in an arc shape; and a plurality of recessed surface parts 112b formed so as to be recessed from the curved surface parts 112a toward the outside of the plate-shaped part <NUM>. Openings 112c which are approximately rectangular shaped are defined by the recessed surface parts 112b.

In the present embodiment, each recessed surface part 112b is formed by three flat surfaces, but each recessed surface part 112b may be formed by a single curved surface. If each recessed surface part 112b is formed by a single curved surface, the openings 112c are defined in an approximately semicircular shape.

The center of each arc-shaped curved surface part 112a is approximately the same, and the curvature radius of each curved surface part 112a is larger than the radius of the piston rod <NUM>. Therefore, in a state in which the bump stopper <NUM> is attached to the cylinder <NUM> (refer to <FIG>), a gap is formed between the inner wall surface of the rod hole <NUM> and the piston rod <NUM>.

As shown in <FIG>, the cylindrical part <NUM> is formed to be continuous with the plate-shaped part <NUM>. In a state in which the cylindrical part <NUM> has received the cylinder <NUM>, the inner surface 111a of the plate-shaped part <NUM> opposes the end surface (oil seal <NUM>) of the cylinder <NUM>.

The cylindrical part <NUM> has a plurality of protrusions <NUM> that protrude toward the inside. The plurality of protrusions <NUM> are formed by depressing the outer peripheral surface of the cylindrical part <NUM>. In a state in which the cylindrical part <NUM> has received the cylinder <NUM>, the plurality of protrusions <NUM> abut the outer peripheral surface of the cylinder <NUM> so as to push open the cylindrical part <NUM>. Therefore, a relatively large force is necessary to pull out the cylinder <NUM> from the cap <NUM>, and the cap <NUM> can be prevented from coming off of the cylinder <NUM>.

The stopper <NUM> is provided to the outer surface 111b of the plate-shaped part <NUM>, and is fixed to the cap <NUM> by projection welding. The bump cushion <NUM> is received and stopped by the stopper <NUM> during contraction of the shock absorber <NUM>.

A circular second rod hole <NUM> is formed in approximately the center of the stopper <NUM> (refer to <FIG>). The bump stopper <NUM> is attached to the cylinder <NUM> in a state in which the piston rod <NUM> is inserted into the second rod hole <NUM>.

The inner peripheral surface of the second rod hole <NUM> of the stopper <NUM> is positioned more toward the inside than the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM>. Therefore, the gap between the stopper <NUM> and the piston rod <NUM> is smaller than the gap between the plate-shaped part <NUM> and the piston rod <NUM>. Thus, regardless of the size of the rod hole <NUM> of the plate-shaped part <NUM>, the bump cushion <NUM> does not readily enter into the gap between the stopper <NUM> and the piston rod <NUM>, and breakage of the bump cushion <NUM> can be prevented.

Since the stopper <NUM> is provided to the outer surface 111b of the plate-shaped part <NUM>, the stopper <NUM> is separated from the oil seal <NUM> in the axial direction of the piston rod <NUM>. Therefore, even if the gap between the stopper <NUM> and the piston rod <NUM> is narrowed, contact between the stopper <NUM> and the oil seal <NUM> (more specifically, the lip 14c) can be prevented.

Since the gap between the plate-shaped part <NUM> and the piston rod <NUM> is larger than the gap between the stopper <NUM> and the piston rod <NUM>, the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM> is separated from the lip 14c in the radial direction of the piston rod <NUM>. Therefore, even if the interval between the plate-shaped part <NUM> and the cylinder <NUM> is narrowed, contact between the plate-shaped part <NUM> and the lip 14c can be prevented.

The collar <NUM> is provided to the inner surface 111a of the plate-shaped part <NUM>, and is fixed to the cap <NUM> by projection welding. In a state in which the bump stopper <NUM> is attached to the cylinder <NUM>, the collar <NUM> opposes the cylinder <NUM> and separates the plate-shaped part <NUM> and the cylinder <NUM>. Therefore, the stopper <NUM> is sufficiently separated from the oil seal <NUM>, and contact between the stopper <NUM> and the oil seal <NUM> can be more reliably prevented.

As shown in <FIG> and <FIG>, the collar <NUM> includes: a plurality of support parts <NUM> that support the plate-shaped part <NUM>; and a plurality of connection parts <NUM> that connect adjacent support parts <NUM>. The plurality of support parts <NUM> are integrated by the connections parts <NUM>. In other words, the collar <NUM> is formed as a single member. Therefore, when attaching the collar <NUM> to the cap <NUM>, the collar <NUM> can be easily handled. The same effect is achieved in the second and third embodiments to be explained below.

A circular third rod hole <NUM> is formed in the collar <NUM> by the plurality of support parts <NUM> and the plurality of connection parts <NUM>. The bump stopper <NUM> is attached to the cylinder <NUM> in a state in which the piston rod <NUM> is inserted into the third rod hole <NUM> of the collar <NUM>.

The radius of the third rod hole <NUM> of the collar <NUM> matches the curvature radius of the curved surface parts 112a of the plate-shaped part <NUM>, and the inner peripheral surface of the third rod hole <NUM> and the curved surface parts 112a are continuous without any level differences therebetween. Since the gap between the plate-shaped part <NUM> and the piston rod <NUM> is larger than the gap between the stopper <NUM> and the piston rod <NUM>, the inner peripheral surface of the third rod hole <NUM>, which is continuous with the curved surface parts 112a of the plate-shaped part <NUM> without any level differences therebetween, is sufficiently separated from the lip 14c in the radial direction of the piston rod <NUM>. Therefore, contact between the collar <NUM> and the lip 14c is prevented.

The plurality of support parts <NUM> are arranged in a radial manner between adjacent openings 112c. Thereby, radial-shaped passages <NUM> which communicate with the openings 112c of the rod hole <NUM> are formed between adjacent support parts <NUM>. The passages <NUM> communicate with the outside of the cylindrical part <NUM> via the gap between the outer peripheral surface of the cylinder <NUM> and the inner peripheral surface of the cylindrical part <NUM>.

The "outside of the cylindrical part <NUM>" indicates the spaces excluding the inside of the cylindrical part <NUM>. Specifically, in <FIG>, the "outside of the cylindrical part <NUM>" includes the space to the left side of the left end of the cylindrical part <NUM>, the space to the right side of the right end of the cylindrical part <NUM>, the space on the top side of the top end of the cylindrical part <NUM>, and the space on the bottom side of the bottom end of the cylindrical part <NUM>. In the present embodiment, the passages <NUM> communicate with the space on the bottom side of the bottom end of the cylindrical part <NUM> via the gap between the outer peripheral surface of the cylinder <NUM> and the inner peripheral surface of the cylindrical part <NUM>.

Since the passages <NUM> are formed between adjacent support parts <NUM>, the passage forming portions of the plate-shaped part <NUM> are supported by the support parts <NUM> on both sides, and thus these passage forming portions do not easily deform. Therefore, deformation of the cross-section shape of the passages <NUM> can be prevented, and fluid and dust that have flowed into the cap <NUM> from the rod hole <NUM> of the plate-shaped part <NUM> can be more reliably discharged to the outside of the cap <NUM>.

A flow of air is generated around the bump cushion <NUM> in accordance with the contraction of the bump cushion <NUM>. Due to this flow of air, air and dust may flow into the gap between the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM> and the piston rod <NUM>. Further, liquid, i.e. water, may flow into the gap between the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM> and the piston rod <NUM>.

In the present embodiment, the passages <NUM> allow the rod hole <NUM> of the plate-shaped part <NUM> to communicate with the outside of the cylindrical part <NUM> via the inside of the cylindrical part <NUM>. Therefore, fluid and dust that have flowed into the gap between the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM> and the piston rod <NUM> is discharged to the outside of the cap <NUM> via the openings 112c of the rod hole <NUM> and the passages <NUM>.

The connection parts <NUM> straddle over the openings 112c of the rod hole <NUM> so as to extend more toward the inside in the radial direction than the recessed surface parts 112b. Therefore, the passages <NUM> communicate with the openings 112c of the rod hole <NUM>. Thus, the flow in the passages <NUM> is not blocked by the connection parts <NUM>, and fluid and dust that flow into the cap <NUM> from the rod hole <NUM> can be more reliably discharged to the outside of the cap <NUM>.

The connection parts <NUM> are not depressed relative to the support parts <NUM>, and are formed in a planar shape along the support parts <NUM>. Therefore, the collar <NUM> is simple. In addition, the collar can be produced easily because it is not necessary to consider a gap between the connection parts <NUM> and the stopper <NUM> so as to avoid contact between the connection parts <NUM> and the stopper <NUM>.

The flow passage cross-section of the passages <NUM> is larger than the flow passage cross-section in the gap between the stopper <NUM> and the piston rod <NUM>. Therefore, fluid and dust that have flowed into the passages <NUM> from this gap do not easily stagnate within the passages <NUM>. Thus, fluid and dust that have flowed into the cap <NUM> from the rod hole <NUM> can be more reliably discharged to the outside of the cap <NUM>.

In the present embodiment, since the passages <NUM> that allow the rod hole <NUM> to communicate with the outside of the cap <NUM> are formed by the cap <NUM> and the collar <NUM>, it is not necessary to form the cap <NUM> in a complex shape. Therefore, the bump stopper <NUM> can be formed easily and reductions in the strength of the bump stopper <NUM> can be prevented.

<FIG> is a bottom view illustrating a bump stopper <NUM> according to an alternative embodiment of the present embodiment. As shown in <FIG>, the circular rod hole <NUM> is formed in the plate-shaped part <NUM>. Further, the collar <NUM> does not include portions corresponding to the connection parts <NUM> (refer to <FIG> and <FIG>), and the plurality of support parts <NUM> are separated from each other. In this bump stopper <NUM> as well, the passages <NUM> are formed by the collar <NUM> and the cap <NUM>. Therefore, the bump stopper <NUM> can be formed easily and reductions in the strength of the bump stopper <NUM> can be prevented.

In the bump stopper <NUM>, since the plurality of support parts <NUM> are separated from each other, there are no members such as the connection parts <NUM> between adjacent support parts <NUM>, and thus the width of the passages <NUM> is expanded. Therefore, flow resistance in the passages <NUM> can be reduced, and fluid and dust that have flowed into the cap <NUM> from the rod hole <NUM> can be more reliably discharged to the outside of the cap <NUM>.

Next, the operation of the shock absorber <NUM> will be explained. Since the bump stopper <NUM> cooperates with the bump cushion <NUM> to absorb shocks only when the shock absorber <NUM> contracts, herein, only the contraction operation of the shock absorber <NUM> will be explained.

When the shock absorber <NUM> contracts, the bump cushion <NUM> abuts the bump stopper <NUM> (refer to <FIG>). Shocks generated during maximum contraction of the shock absorber <NUM> are absorbed by the contraction of the bump cushion <NUM>.

A flow of air is generated around the bump cushion <NUM> in accordance with the contraction of the bump cushion <NUM>. At this time, fluid and dust flow into the gap between the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM> and the piston rod <NUM>.

Fluid and dust that have flowed into the gap between the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM> and the piston rod <NUM> is discharged to the outside of the cap <NUM> via the passages <NUM> (the passages indicated by the arrow mark in <FIG>). Therefore, increases in the pressure within the cap <NUM> and accumulations of dust within the cap <NUM> can be prevented.

Next, referring to <FIG>, a bump stopper <NUM> according to a second embodiment of the present invention will be explained. Constituent elements which are the same as those in the first embodiment will be assigned the same reference numerals, and explanations thereof will be omitted.

<FIG> is a cross-section view of a shock absorber <NUM> provided with the bump stopper <NUM>. <FIG> is a bottom view of the bump stopper <NUM>. <FIG> is a cross-section view along line IX-IX shown in <FIG>.

The bump stopper <NUM> includes the following: the cap <NUM>; the stopper <NUM>; and a collar <NUM> provided to the inside of the cap <NUM>. The collar <NUM> includes a plurality of support parts <NUM>, and a plurality of connection parts <NUM> which connect adjacent support parts <NUM>.

The connection parts <NUM> are depressed in the axial direction of the piston rod <NUM> relative to the support parts <NUM> so that the connection parts <NUM> enter into the rod hole <NUM>. Specifically, as shown in <FIG>, each connection part <NUM> includes base parts 232a formed to be continuous with the support parts <NUM>, and a middle part 232b formed to be continuous with the base parts 232a. The base parts 232a are bent toward the stopper <NUM>, and the middle part 232b contacts the stopper <NUM>.

In the embodiment shown in <FIG>, the thickness of the connection parts <NUM> is approximately equal to the thickness of the support parts <NUM>, and the depression of the connection parts <NUM> is formed by bending the base parts 232a. Therefore, the connection parts protrude in the axial direction of the piston rod <NUM> relative to the support parts <NUM>.

The depression of the connection parts <NUM> may be formed without bending the base parts 232a. For example, the depression may be formed by making the thickness of the connection parts <NUM> less than the thickness of the support parts <NUM>.

In addition to the effects achieved by the bump stopper <NUM> according to the first embodiment, the bump stopper <NUM> also achieves the following effects.

Since the connection parts <NUM> are depressed, passages <NUM> are formed linearly along the end surface of the cylinder <NUM> (surface of the oil seal <NUM>) between the connection parts <NUM> and the cylinder <NUM> as shown in <FIG>. Therefore, flow resistance in the passages <NUM> can be reduced, and fluid and dust that have flowed into the cap <NUM> from the rod hole <NUM> can be more reliably discharged to the outside of the cap <NUM>. The same effects are also achieved in the third embodiment to be explained below.

The connection parts <NUM> do not have to contact the stopper <NUM>. Further, the connection parts <NUM> may contact the inner wall surface of the rod hole <NUM>.

The operation of the shock absorber <NUM> is basically the same as that of the shock absorber <NUM>, and thus an explanation thereof will be omitted herein.

Next, referring to <FIG> and <FIG>, a bump stopper <NUM> according to a third embodiment of the present invention will be explained. Constituent elements which are the same as those in the first and second embodiments will be assigned the same reference numerals, and explanations thereof will be omitted.

<FIG> is a cross-section view of a shock absorber <NUM> provided with the bump stopper <NUM>. <FIG> is a bottom view of the bump stopper <NUM>.

The bump stopper <NUM> includes: a cap <NUM>; the stopper <NUM>; and a collar <NUM> provided to the inside of the cap <NUM>. A circular rod hole <NUM> is formed in a plate-shaped part <NUM> of the cap <NUM>. The piston rod <NUM> can be inserted into the rod hole <NUM>.

A connection part <NUM> of the collar <NUM> is positioned more toward the inside in the radial direction than the circular inner peripheral surface of the rod hole <NUM>. In addition, the connection part <NUM> is formed to be depressed relative to the support parts <NUM>.

If the connection parts <NUM> are depressed so as to fit into the openings 112c as shown in <FIG>, a raised part S of the depression is formed in the flow passage cross-section of the passages <NUM>. The passages <NUM> are narrowed by an amount equivalent to the raised part S.

In the present embodiment, since the connection part <NUM> is positioned more toward the inside in the radial direction than the circular inner peripheral surface of the rod hole <NUM>, there is no raised part of the depression in the flow passage cross-section of the passages <NUM>, and the width of the passages <NUM> is expanded. Therefore, flow resistance in the passages <NUM> can be reduced, and fluid and dust that have flowed into the cap <NUM> from the rod hole <NUM> can be more reliably discharged to the outside of the cap.

The connection part <NUM> of the collar <NUM> is formed in an annular shape and includes a third rod hole <NUM>. The piston rod <NUM> can be inserted into the third rod hole <NUM>. The plurality of support parts <NUM> are disposed on the outer periphery of the annular connection part <NUM>. The collar <NUM> is fixed to the cap <NUM> by joining the connection part <NUM> and the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM>.

The connection part <NUM> is disposed within the rod hole <NUM> of the plate-shaped part <NUM>. Therefore, the connection part <NUM> is not covered by the cap <NUM>. Thus, when the collar <NUM> is fixed to the cap <NUM>, the connection part <NUM> can be seen from the outside of the cap <NUM>, and the connection part <NUM> can be easily joined to the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM>.

The connection part <NUM> may or may not contact the stopper <NUM>.

In addition to the effects achieved by the bump stoppers <NUM> and <NUM> according to the first and second embodiments, the bump stopper <NUM> also achieves the following effects.

Since the connection part <NUM> is not covered by the cap <NUM>, when the collar <NUM> is fixed to the cap <NUM>, the connection part <NUM> can be seen from the outside of the cap <NUM>, and the connection part <NUM> can be easily joined to the inner peripheral surface of the rod hole <NUM> of the plate-shaped part <NUM>.

The operation of the shock absorber <NUM> is basically the same as that of the shock absorber <NUM>, and thus an explanation thereof will be omitted herein.

The constitution, operation, and effects of the embodiments of the present invention will now be summarized below.

In the present embodiments, the bump stopper <NUM>, <NUM>, <NUM>, <NUM> absorbs shocks generated during maximum contraction of the shock absorber <NUM>, <NUM>, <NUM> in cooperation with the bump cushion <NUM>. The bump stopper <NUM>, <NUM>, <NUM>, <NUM> includes the following: the cap <NUM>, <NUM> provided with the plate-shaped part <NUM>, <NUM> having the rod hole <NUM>, <NUM> into which the piston rod <NUM> of the shock absorber <NUM>, <NUM>, <NUM> inserted, and the cylindrical part <NUM> configured to receive a portion of the cylinder <NUM> of the shock absorber <NUM>, <NUM>, <NUM>; the stopper <NUM> provided to the plate-shaped part <NUM>, <NUM> and configured to receive the bump cushion <NUM>; and the collar <NUM>, <NUM>, <NUM> provided to the plate-shaped part <NUM>, <NUM> opposing the cylinder <NUM>.

In the above constitution, since the collar <NUM>, <NUM>, <NUM> is provided to the plate-shaped part <NUM>, <NUM> opposing the cylinder <NUM>, it is not necessary to form the cap <NUM>, <NUM> in a complex shape. Therefore, the bump stopper <NUM>, <NUM>, <NUM>, <NUM> which is easy to manufacture and has sufficient strength can be provided.

In the present embodiments, in the bump stopper <NUM>, <NUM>, <NUM>, <NUM>, the collar <NUM>, <NUM>, <NUM> includes the plurality of support parts <NUM> arranged in a radial manner on the plate-shaped part <NUM>, <NUM> and configured to support the plate-shaped part <NUM>, <NUM>, and the passages <NUM>, <NUM>, <NUM> which is configured to allow the rod hole <NUM>, <NUM> to communicate with the outside of the cap <NUM>, <NUM> via the inside of the cylindrical part <NUM>, are formed by the cap <NUM>, <NUM> and the collar <NUM>, <NUM>, <NUM>. The passages <NUM>, <NUM>, <NUM> are formed between adjacent support parts <NUM>.

In the above constitution, since the passages <NUM>, <NUM>, <NUM> are formed between adjacent support parts <NUM>, the passage forming portions of the plate-shaped part <NUM>, <NUM> are supported by the support parts <NUM> on both sides, and thus these passage forming portions do not easily deform. Therefore, deformation of the cross-section shape of the passages <NUM>, <NUM>, <NUM> can be prevented, and fluid and dust that have flowed into the cap <NUM>, <NUM> from the rod hole <NUM>, <NUM> can be more reliably discharged to the outside of the cap <NUM>, <NUM>.

In the present embodiments, in the bump stopper <NUM>, <NUM>, <NUM>, the collar <NUM>, <NUM>, <NUM> further includes the connection parts <NUM>, <NUM>, <NUM> that connect adjacent support parts <NUM>.

In the above constitution, since the connection parts <NUM>, <NUM>, <NUM> connect adjacent support parts <NUM>, the plurality of support parts <NUM> are integrated by the connection parts <NUM>, <NUM>, <NUM>. Thus, the collar <NUM>, <NUM>, <NUM> can be easily handled.

In the present embodiments, in the bump stopper <NUM>, the rod hole <NUM> has the openings 112c, and the connection parts <NUM> are positioned more toward the inside in the radial direction than the inner peripheral surface of the openings 112c and are formed in a planar shape along the support parts <NUM>.

In the above constitution, since the connection parts <NUM> are formed in a planar shape along the support parts <NUM>, the collar <NUM> is simple. In addition, the collar <NUM> can be produced easily because it is not necessary to produce the collar <NUM> in consideration of a gap between the connection parts <NUM> and the stopper <NUM> so as to avoid contact between the connection parts <NUM> and the stopper <NUM>.

In the present embodiments, in the bump stopper <NUM>, the rod hole <NUM> has the openings 112c, and the connection parts <NUM> are positioned more toward the inside in the radial direction than the inner peripheral surface of the openings 112c and are formed to be depressed relative to the support parts <NUM>.

In the above constitution, since the connection parts <NUM> are formed to be depressed relative to the support parts <NUM>, the passages <NUM> are formed linearly along the end surface of the cylinder <NUM>. Therefore, flow resistance in the passages <NUM> can be reduced, and fluid and dust that have flowed into the cap <NUM> from the rod hole <NUM> can be more reliably discharged to the outside of the cap <NUM>.

In the present embodiments, in the bump stopper <NUM>, the rod hole <NUM> is circular, and the connection part <NUM> is positioned more toward the inside in the radial direction than the circular inner peripheral surface of the rod hole <NUM> and is formed to be depressed relative to the support parts <NUM>.

In the above constitution, since the connection part <NUM> is positioned more toward the inside in the radial direction than the circular inner peripheral surface of the rod hole <NUM>, there is no raised part of the depression in the flow passage cross-section of the passages <NUM>, and the width of the passages <NUM> is expanded. Therefore, flow resistance in the passages <NUM> can be reduced, and fluid and dust that have flowed into the cap <NUM> from the rod hole <NUM> can be more reliably discharged to the outside of the cap <NUM>.

In the present embodiments, in the bump stopper <NUM>, the connection part <NUM> is formed in an annular shape and is disposed within the rod hole <NUM> of the plate-shaped part <NUM>.

In the above constitution, since the annular connection part <NUM> is disposed within the rod hole <NUM>, the connection part <NUM> is not covered by the cap <NUM>. Thus, when the collar <NUM> is fixed to the cap <NUM>, the connection part <NUM> can be seen from the outside of the cap <NUM>, and the connection part <NUM> can be easily joined to the inner wall surface of the rod hole <NUM>.

In the present embodiments, in the bump stopper <NUM>, the plurality of support parts <NUM> are separated from each other.

In the above constitution, since the plurality of support parts <NUM> are separated from each other, there are no members such as the connection parts <NUM> between adjacent support parts <NUM>, and thus the width of the passages <NUM> is expanded. Therefore, flow resistance in the passages <NUM> can be reduced, and fluid and dust that have flowed into the cap <NUM> from the rod hole <NUM> can be more reliably discharged to the outside of the cap <NUM>.

In the present embodiments, the bump stopper <NUM>, <NUM>, <NUM>, <NUM> is characterized in that the inner peripheral surface of the stopper <NUM> is positioned more toward the inside in the radial direction than the inner peripheral surface of the rod hole <NUM>, <NUM> of the plate-shaped part <NUM>, <NUM>.

In the above constitution, since the inner peripheral surface of the stopper <NUM> is positioned more toward the inside than the inner peripheral surface of the rod hole <NUM>, <NUM>, of the plate-shaped part <NUM>, <NUM>, the gap between the stopper <NUM> and the piston rod <NUM> is smaller than the gap between the inner peripheral surface of the rod hole <NUM>, <NUM> and the piston rod <NUM>. Thus, regardless of the size of the rod hole <NUM>, <NUM>, the bump cushion <NUM> does not readily enter into the gap between the stopper <NUM> and the piston rod <NUM>, and breakage of the bump cushion <NUM> can be prevented.

In the present embodiments, the shock absorber <NUM>, <NUM>, <NUM> is characterized by including the bump stopper <NUM>, <NUM>, <NUM>, <NUM> described above and the piston rod <NUM> inserted into the rod hole <NUM>, <NUM>, wherein the flow passage cross-section of the passages <NUM>, <NUM>, <NUM> is larger than the flow passage cross-section in the gap between the stopper <NUM> and the piston rod <NUM>.

Claim 1:
A bump stopper (<NUM>, <NUM>, <NUM>, <NUM>) for absorbing shocks generated during maximum contraction of a shock absorber (<NUM>, <NUM>, <NUM>) in cooperation with a bump cushion (<NUM>), the bump stopper (<NUM>, <NUM>, <NUM>, <NUM>) comprising:
a cap (<NUM>, <NUM>) including a plate-shaped part (<NUM>, <NUM>) having a rod hole (<NUM>, <NUM>) into which a piston rod (<NUM>) of the shock absorber (<NUM>, <NUM>, <NUM>) may be inserted, and a cylindrical part (<NUM>) configured to receive a portion of a cylinder (<NUM>) of the shock absorber (<NUM>, <NUM>, <NUM>); a stopper (<NUM>) provided to the plate-shaped part (<NUM>, <NUM>), the stopper (<NUM>) being configured to receive the bump cushion (<NUM>); and
a collar (<NUM>, <NUM>, <NUM>) provided to the plate-shaped part (<NUM>, <NUM>) configured so that it opposes the cylinder (<NUM>) in an assembled state,
wherein
the collar (<NUM>, <NUM>, <NUM>) comprises a plurality of support parts (<NUM>) arranged in a radial manner on the plate-shaped part (<NUM>, <NUM>), the plurality of support parts (<NUM>) being configured to support the plate-shaped part (<NUM>, <NUM>),
a passage (<NUM>, <NUM>, <NUM>) is formed by the cap (<NUM>, <NUM>) and the collar (<NUM>, <NUM>, <NUM>), the passage (<NUM>, <NUM>, <NUM>) being configured to allow the rod hole (<NUM>, <NUM>) to communicate with an outside of the cylindrical part (<NUM>) via an inside of the cylindrical part (<NUM>), and
the passage (<NUM>, <NUM>, <NUM>) is formed between the adjacent support parts (<NUM>).