JP7341917B2 - buffer - Google Patents

Description

The present invention relates to a shock absorber.

A shock absorber includes an outer shell and a piston rod that is movably inserted into the outer shell, and is used, for example, by being incorporated into a suspension of a vehicle, and is used for expansion and contraction in which the piston rod moves in the axial direction with respect to the outer shell. At times, it exerts a damping force to suppress vibrations in the vehicle body and wheels. The shock absorber built into the suspension is constructed by intervening between the vehicle body and the wheels, for example, by a mount that connects the piston rod to the vehicle body and a bracket that connects the outer shell to the knuckle that holds the wheel. equipped.

When the suspension is a double wishbone, the outer shell T is connected to a lower arm that swingably connects the knuckle to the vehicle body, instead of being connected to the knuckle via the bracket B, as shown in Fig. 3. There is.

In addition, when the shock absorber is incorporated into a suspension that suspends a drive wheel, the bracket B needs to avoid the drive shaft and place the outer shell T above the drive shaft. Therefore, the bracket B is configured to include a cylindrical gripping part b1 that grips the lower end of the outer shell T, and a fork b2 that extends bifurcated from the gripping part b1 and into which the drive shaft is inserted.

Therefore, in a shock absorber to which such a bracket B is attached, a bracket attachment portion t1 to which the bracket B is attached is formed below the stopper S attached to the outer periphery of the lower end of the outer shell T (for example, (See Patent Document 1).

In such a conventional shock absorber, a disc-shaped lid member called a lower cap C that closes the lower end of the outer shell T is attached to the lower end of the outer shell T by welding. Specifically, the lower cap C is welded to a small diameter portion t2 formed by reducing the lower end diameter of the outer shell T by one step, and by providing the small diameter portion t2 in this way, the lower end of the outer shell T and the lower The bead formed on the outer periphery of the cap C does not get in the way when the bracket B is inserted from the lower end side. Therefore, the bracket mounting portion t1 is formed at a portion on the lower end side of the outer shell T where there is no change in diameter between the small diameter portion t2 and the stopper S.

Japanese Patent Application Publication No. 2008-82492

The lower cap C may be provided with an injection port for injecting hydraulic oil and gas into the outer shell T after various parts constituting the shock absorber such as valves and cylinders are incorporated therein. . After the hydraulic oil and gas are injected, a plug is inserted into the injection port provided in the lower cap to temporarily seal the outer shell, and a disc-shaped lid W called a washer is projected onto the lower cap C using a welding machine. The outlet of the inlet is closed by welding.

The lower cap C has a disc shape so that the welding machine does not interfere with the welding of the lid W, and is also provided with a convex part c1 that projects downward, and the injection port is located in the convex part c1. It's open . Since the lid W is welded to the convex portion c1 that projects downward from the main body of the lower cap C, it inevitably projects downward from the lower cap C.

The shock absorber configured in this way is incorporated into a double wishbone type suspension using the bracket B mentioned above, but in order to obtain sufficient connection strength against the bending force acting on the bracket B, the gripping portion There are cases where it is desired to increase the length of b1.

In order to increase the length of the gripping part b1, the length of the bracket attachment part t1 on the outer shell T will inevitably become longer. The lid W that protrudes downward is disposed downward by the length of the bracket mounting portion t1, and there is a possibility that the lid W may interfere with the drive shaft.

However, when providing the aforementioned small diameter portion t2 on the outer shell T, the diameter of the outer shell T is rapidly reduced to provide the small diameter portion t2, and the length of the portion between the bracket mounting portion t1 and the small diameter portion t2 is If an attempt is made to shorten the length, the shape changes drastically and problems arise in terms of strength, so it is difficult to shorten the length of the portion t3 between the bracket mounting portion t1 and the small diameter portion t2.

Therefore, the conventional shock absorber has a problem in that even if an attempt is made to ensure the length of the bracket mounting portion t1, interference with vehicle-side components is unavoidable, making it difficult to mount it on a vehicle.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a shock absorber whose bracket attachment portion can be made longer without impairing its mountability on a vehicle.

In order to solve the above-mentioned problems, the shock absorber of the present invention has a cylindrical shape, and has a bracket mounting part into which a bracket for supporting wheels of a vehicle is fitted on the outer periphery of the lower end side , and a lower end below the bracket mounting part. The lower cap includes an outer shell having a reduced diameter portion formed by reducing the diameter , and a lower cap welded to the lower end of the outer shell to close the lower end of the outer shell. a lower cap body having an annular skirt protruding from the outer periphery of the cap toward the side opposite to the outer shell, the mirror part and the skirt part forming a recess; and one of gas and liquid passing through the mirror part into the outer shell. Alternatively, it includes an injection port that enables injection of both, and a lid that is welded to the mirror portion to close the injection port , and the outer periphery of the skirt portion is welded to the lower end of the reduced diameter portion . According to the shock absorber configured in this way, even if the total length of the outer shell is increased, the length from the upper end of the outer shell to the lid can be made equal to the length from the outer shell to the lid of a conventional shock absorber , and Since the welding part of the lower cap can be brought closer to the lower end of the lower cap, it is advantageous in extending the total length of the outer shell, and the total length of the bracket attachment part can be increased more effectively.

Further, the lower end of the skirt portion of the lower cap may protrude below the lower end of the lid, and according to the shock absorber configured in this way, the lid can be completely housed in the recess, and the lid can be protected.

As described above, according to the shock absorber of the present invention, the length of the bracket attachment portion can be increased without impairing mountability on a vehicle.

FIG. 2 is a side view of a shock absorber in one embodiment. FIG. 3 is an enlarged cross-sectional view of the lower end of the shock absorber in one embodiment. FIG. 2 is a side view of a conventional shock absorber.

The present invention will be described below based on the embodiments shown in the figures. As shown in FIGS. 1 and 2, the shock absorber D includes an outer shell 1 that is cylindrical and has a bracket mounting portion 1a on the outer periphery of the lower end side into which a bracket 3 that supports the wheels of a vehicle (not shown) is fitted; The lower cap 2 is welded to the lower end 1b of the outer shell 1 to close the lower end 1b of the outer shell 1, and is connected to a lower arm (not shown) of the vehicle using a bracket 3.

Although not shown in detail, the shock absorber D includes a cylindrical outer shell 1, a lower cap 2 that closes the lower end of the outer shell 1, a cylinder 4 inserted into the outer shell 1, and a cylinder 4 that is movable into the cylinder. It includes a piston rod 5 to be inserted, and a piston connected to the piston rod 5 and inserted into the cylinder 4 to partition the inside of the cylinder 4 into a expansion side chamber and a compression side chamber 6.

The expansion side chamber and the compression side chamber 6 are filled with hydraulic oil. Further, the liquid used in the shock absorber D may be other than hydraulic oil, for example, a liquid such as water or an aqueous solution. The annular gap between the outer shell 1 and the cylinder 4 is used as a reservoir 8, and is filled with hydraulic oil and gas as liquids.

The piston includes an expansion side port and a compression side port that communicate the expansion side chamber and the compression side chamber 6, and a compression side leaf valve and an expansion side leaf valve are stacked on the upper surface and the lower surface of the piston, respectively. The growth-side leaf valve closes the lower end of the growth-side port, and when bent by the pressure of the growth-side chamber, opens the growth-side port and provides resistance to the flow of liquid from the growth-side chamber toward the pressure-side chamber 6. The pressure side leaf valve closes the upper end of the pressure side port, and is bent by the pressure of the pressure side chamber 6 to open the pressure side port and provide resistance to the flow of liquid from the pressure side chamber 6 to the expansion side chamber.

Note that a rod guide that slides on the outer periphery of the piston rod 5 is attached to the upper end of the outer shell 1. Further, a valve case 7 is fitted to the lower end of the cylinder 4, and the cylinder 4 and the valve case 7 are sandwiched between the lower cap 2 welded to the lower end of the outer shell 1 and the rod guide, and the cylinder 4 and the valve case 7 are held together by the lower end of the outer shell 1. Fixed against.

Further, the valve case 7 includes a suction port 7a and a discharge port 7b that communicate the reservoir 8 and the pressure side chamber 6. The upper end of the suction port 7a is closed by an annular check valve 9. When the pressure in the reservoir 8 becomes higher than the pressure in the pressure side chamber 6, the check valve 9 bends to open the suction port 7a and allow liquid to flow from the reservoir 8 to the pressure side chamber 6. Block the flow of liquid towards. The lower end of the discharge port 7b is closed by an annular base valve 10. The base valve 10 is bent by the pressure of the pressure side chamber 6 to open the discharge port 7b and provide resistance to the flow of liquid from the pressure side chamber 6 toward the reservoir 8.

In the shock absorber D, when the piston rod 5 moves upward with respect to the outer shell 1 during expansion, the leaf valve on the expansion side acts against the flow of liquid moving from the expansion side chamber compressed by the piston to the pressure side chamber 6 expanding. Generates a damping force that provides resistance and prevents elongation. When the shock absorber D is extended, the check valve 9 is opened and hydraulic oil is supplied from the reservoir 8 to the pressure side chamber 6 via the suction port 7a, and the volume of the piston rod 5 withdrawn from the cylinder 4 is compensated for. On the other hand, during contraction when the piston rod 5 moves downward with respect to the outer shell 1, the shock absorber D acts as a leaf valve on the pressure side for the flow of liquid that moves from the pressure side chamber 6 compressed by the piston to the expansion side chamber expanded. provides resistance. Further, when the shock absorber D is contracted, the base valve 10 is opened and the hydraulic oil is discharged from the pressure side chamber 6 to the reservoir 8 via the discharge port 7b, and the volume of the piston rod 5 entering the cylinder 4 is compensated for. Therefore, when the shock absorber D is contracted, the leaf valve on the pressure side and the base valve 10 generate a damping force that prevents the contraction. Note that the pressure-side leaf valve stacked on the piston may be a check valve, in which case the pressure-side damping force is generated only by the base valve 10.

The shock absorber D described above is a so-called double-tube type shock absorber, but a piston is brought into sliding contact with the inner periphery of the outer shell 1, and the inside of the outer shell 1 is partitioned into a growth side chamber and a compression side chamber by the piston. It may be a so-called monocylindrical shock absorber.

As shown in FIGS. 1 and 2, a C-shaped stopper 11 is welded to the outer periphery of the lower end of the outer shell 1, and the bracket 3 is attached to the outer periphery of the outer shell 1 below the stopper 11. A bracket mounting portion 1a whose outer diameter does not change is provided. The stopper 11 includes a C-shaped main body 11a that fits around the outer periphery of the outer shell 1, and a guide piece 11b that projects in the radial direction from the terminal end of the main body 11a and extends below the main body 11a. The guide piece 11b is used for positioning the bracket 3, which will be described later.

A recess 1c is provided in the bracket mounting portion 1a of the outer shell 1 along the horizontal direction. The recessed portion 1c has an arcuate concave shape when viewed from the horizontal direction.

The diameter of the area below the bracket attachment part 1a of the outer shell 1 is reduced so that the bead 12 produced when the lower cap 2 is welded to the lower end 1b of the outer shell 1 does not interfere with the attachment of the bracket 3. 1d is formed.

The bracket 3 includes a split C-shaped holding part 3a that holds the bracket mounting part 1a of the outer shell 1, and a hole (not shown) provided at one end of the holding part 3a and through which a bolt 13 is inserted. a bolt receiving part 3b, a nut part 3c provided at the other end of the holding part 3a and facing the bolt receiving part 3b, and a bifurcated fork part 3d formed by a pair of arms extending downward from the holding part 3a. It is equipped with As described above, in this embodiment, the bracket 3 is a so-called fork bracket.

The bracket 3 configured in this manner is attached to the outer shell 1 in the following manner. First, the lower end of the outer shell 1 is inserted into the holding part 3a from below the outer shell 1, the upper end of the holding part 3a is brought into contact with the lower end of the stopper 11, and the guide piece 11b is inserted into the holding part 3a. Insert within Wariuchi. Then, although the holding part 3a of the bracket 3 is only allowed to rotate slightly in the circumferential direction by the guide piece 11b, its upward movement relative to the outer shell 1 is restricted by the main body 11a of the stopper 11, and the outer shell It is positioned on the outer periphery of the bracket mounting portion 1a of No. 1. Then, when the bolt 13 is inserted into the hole of the bolt receiving part 3b and then screwed into the nut part 3c, both ends of the holding part 3a are drawn together by the screwing of the bolt 13, and the holding part 3a has a reduced diameter. Then, grip the bracket mounting portion 1a of the outer shell 1 with strong tension. In addition, the bolt 13 is attached to the outer shell 1 together with the bracket 3 while being inserted into a recess 1c provided in the outer shell 1, which prevents the bracket 3 from coming off from the outer shell 1 and preventing the bracket 3 from coming off in the circumferential direction. The bracket 3 is firmly fixed to the outer shell 1.

As shown in FIG. 2, the lower cap 2 includes a disk-shaped mirror portion 20a and an annular skirt portion 20b that protrudes downward in FIG. 2 from the outer periphery of the mirror portion 20a on the side opposite to the outer shell. 20a and a skirt portion 20b forming a recess 20c; an inlet 21 that penetrates the mirror portion 20a and allows gas and liquid to be injected into the outer shell 1; and a lid 22 that closes the injection port 21.

The mirror portion 20a includes a convex portion 20d projecting downward in a spherical shape at the center of the lower end, and also includes a fitting recess 20e into which the valve case 7 is fitted at the upper end in FIG. 2, which is the outer shell side end. The injection port 21 opens from the convex portion 20d, passes through the mirror portion 20a, communicates with the fitting recess 20e, and communicates the inside of the outer shell 1 with the outside of the buffer D.

The skirt portion 20b protrudes downward in an annular shape along the outer periphery of the mirror portion 20a. In other words, the skirt portion 20b is formed to surround the entire outer circumference of the mirror portion 20a. The height from the lower end of the skirt portion 20b to the lower surface of the mirror portion 20a is equal to or greater than the total height of the convex portion 20d plus the height of the lid 22 welded to the convex portion 20d. The skirt portion 20b is tall and protrudes below the lower end of the lid 22. A disc-shaped recess 20c is formed inside the skirt portion 20b and below the mirror portion 20a, and the entire lid 22 is completely accommodated in the recess 20c. Note that by setting the height from the lower end of the skirt portion 20b to the lower surface of the mirror portion 20a to be greater than or equal to the above-mentioned total height, a portion of the lid 22 may protrude downward from the lower end of the skirt portion 20b due to dimensional errors or processing reasons. Even so, the amount of protrusion of the lid 22 can be minimized.

The lower cap 2 configured in this manner is fitted to the inner periphery of the lower end 1b of the outer shell 1 with only the skirt portion 20b protruding from the lower end 1b of the outer shell 1, and then the skirt portion 20b and the outer shell 1 are fitted together. The lower end 1b of is welded over the entire circumference. A welded bead 12 is formed between the outer periphery of the skirt portion 20b and the lower surface of the lower end 1b of the outer shell 1, and a reduced diameter portion 1d is provided closer to the lower end 1b than the bracket attachment portion 1a of the outer shell 1. The outer diameter of the bead 12 is smaller than the inner diameter of the holding part 3a of the bracket 3, so that it does not interfere with the mounting of the bracket 3.

In this way, the lower cap 2 is attached to the lower end 1b of the outer shell 1, and all parts such as the cylinder 4, piston rod 5, piston, valve case, valves, rod guide, etc. that make up the shock absorber D are attached to the outer shell 1. Assemble. When the mechanical parts of the shock absorber D are assembled in this way, hydraulic oil and gas are injected from the injection port, and the reservoir 8 is filled with gas and hydraulic oil, and the expansion side chamber and the compression side chamber 6 are is filled with hydraulic oil. In addition, when the shock absorber D is a single cylinder type shock absorber, since an air chamber is formed at the lower end of the shock absorber, only gas is injected from the injection port 21. Further, depending on the configuration of the buffer D, the injection port 21 may not be used for injecting gas but only for injecting liquid.

After the hydraulic oil and gas are injected into the buffer D, a plug 23 is fitted into the injection port 21 to temporarily seal the injection port 21. After temporarily sealing the injection port 21 with the plug 23, the lid 22 is placed on the convex portion 20d of the lower cap 2, and the open end of the injection port 21 is covered with the lid 22. Then, when the lid 22 is fixed to the lower cap body 20 by projection welding to the convex portion 20d using a welding machine (not shown), the injection port 21 is completely closed and the inside of the outer shell 1 is sealed.

In the shock absorber D of this embodiment, the lower cap 2 includes a recess 20c , and by providing the recess 20c, the lower end of the lid 22 that closes the injection port 21 protrudes downward from the lower end of the lower cap 2. The amount of protrusion can be reduced. In the case of this embodiment, the lid 22 is completely accommodated in the recess 20c, so the amount of protrusion is zero.

In this way, since the amount by which the lid 22 protrudes downward from the lower end of the lower cap 2 is reduced, the entire length of the outer shell 1 is extended compared to the conventional shock absorber, and the lower cap 2 is welded to the lower end 1b of the outer shell 1. However, since the amount of protrusion of the lid 22 is reduced, the length from the upper end of the outer shell 1 to the lid 22 can be made equal to the length from the outer shell T to the lid W of a conventional shock absorber. In other words, in the conventional shock absorber, as shown in FIG. 3, there was an unnecessary length L2 between the welded part of the lower cap C and the lower end of the lid W. However, as shown in FIG. In the shock absorber D of the form, since the recess 20c is provided in the lower cap 2, the length L1 between the welded portion and the lower end of the lid 22 is shortened. Therefore, even if the total length of the outer shell 1 is increased by that amount, the length from the upper end of the outer shell 1 to the lid 22 can be made equal to the length from the outer shell T to the lid W of a conventional shock absorber. Then, the overall length of the bracket attachment portion 1a can be increased by an amount corresponding to the increased overall length of the outer shell 1, and the strength of connection of the bracket 3 to the outer shell 1 can be improved. Furthermore, even if the total length of the outer shell 1 is longer than the outer shell T of a conventional shock absorber, the length from the upper end of the outer shell 1 to the lid 22 is the same as the length from the outer shell T to the lid W of a conventional shock absorber. Since they can be made the same, there is no fear that the lid 22 will interfere with the drive shaft even if the shock absorber D is incorporated into a double wishbone type suspension (not shown).

As described above, the shock absorber D of the present embodiment includes an outer shell 1 which is cylindrical and has a bracket mounting portion 1a on the outer periphery of the lower end side into which a bracket 3 for supporting wheels of a vehicle is fitted, and a lower end of the outer shell 1. 1b to close the lower end 1b of the outer shell 1, the lower cap 2 includes a disk-shaped mirror portion 20a and an annular skirt portion protruding from the outer periphery of the mirror portion 20a toward the side opposite to the outer shell. 20b, and a mirror portion 20a and a skirt portion 20b form a concave portion 20c; gas and hydraulic oil (liquid) can be injected into the outer shell 1 through the mirror portion 20a; A lid 22 is welded to the mirror portion 20a to close the injection port 21. According to the shock absorber D configured in this way, even if the total length of the outer shell 1 is increased, the length from the upper end of the outer shell 1 to the lid 22 is the same as the length from the outer shell T to the lid W of a conventional shock absorber. Therefore, the length of the bracket mounting portion 1a can be increased without impairing mountability on a vehicle.

Further, in the shock absorber D of the present embodiment, the lower end of the skirt portion 20b of the lower cap 2 protrudes below the lower end of the lid 22, so that the lid 22 can be completely accommodated in the recess 20c. can be protected.

Furthermore, in the shock absorber D of this embodiment, since the outer periphery of the skirt portion 20b of the lower cap 2 is welded to the lower end 1b of the outer shell 1, the welded part of the lower cap 2 can be brought close to the lower end of the lower cap 2. This is advantageous in extending the total length of the outer shell 1, and the total length of the bracket attachment portion 1a can be increased more effectively.

In the shock absorber D of this embodiment, the bracket 3 is a fork bracket, and the shock absorber D is connected to the lower arm of the suspension. It may extend from a knuckle rotatably holding a wheel as shown in FIG.

Although the preferred embodiments of the present invention have been described in detail above, modifications, variations, and changes can be made without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1... Outer shell, 1a... Bracket attachment part, 1b... Lower end of outer shell, 2... Lower cap, 3... Bracket, 20... Lower cap body, 20a... Mirror Part, 20b... Skirt part, 20c... Recessed part, 21... Inlet, 22... Lid

Claims (2)

An outer shell that is cylindrical and has a bracket mounting part into which a bracket for supporting wheels of a vehicle is fitted on the outer periphery of the lower end side , and a reduced diameter part formed by reducing the diameter of the lower end below the bracket mounting part. and,
a lower cap welded to the lower end of the outer shell to close the lower end of the outer shell;
The lower cap includes a lower cap body including a disc-shaped mirror portion and an annular skirt portion protruding from the outer periphery of the mirror portion toward a side opposite to the outer shell, and the mirror portion and the skirt portion form a recessed portion. , having an injection port that penetrates the mirror section and allows one or both of gas and liquid to be injected into the outer shell, and a lid that is welded to the mirror section and closes the injection port,
The outer periphery of the skirt portion is welded to the lower end of the reduced diameter portion.
A buffer characterized by: The shock absorber according to claim 1, wherein a lower end of the skirt portion projects further downward than a lower end of the lid.